microsoft word 13. baj-234sc_revised.docx short communication bangladesh agron. j. 2016, 19(1): 109-113 comparative growth performances of tea saplings raised in the poly and gunny bags m. m. rana1*, s. m. a. hossain2, m. i. hossain3, m. s. huq4 and m. m. rahman5 1senior scientific officer, agronomy division. 2chief scientific officer, crop production department. 3principal scientific officer, botany division. 4farm supervisor, agronomy division. 5senior field assistant, botany division. *corresponding author: ranabtri@yahoo.com key words: tea, sapling, growth, poly bag, jute bag. polythene or poly bags (plastic bags) are widely used for raising young plants in the nursery which are cheap, light weight, extremely durable and widely available. plastic bags are principally used to raise tea saplings/seedlings in the nursery. the drawback of the plastic bags made the planters think to find out alternate eco-friendly materials for raising tea saplings. jute fiber, which comes from a plant called jute (corchorus spp.) is mostly consisting of cellulose, is 100% bio-degradable and recyclable and thus environmentally friendly (fao, 2015). jute has gained an advantage as being an eco-friendly option instead of poly and paper bags. poly bags are non-biodegradable and manufacturing paper bags requires large quantities of wood. jute has none of these problems but higher cost is a setback for it. some other disadvantages of jute may include a decreased strength when wet, and also becomes subject to microbial attack in humid climates. for tree nurseries in general, physiological quality criteria are prioritized for seedling establishment after planting (villar-salvador et al., 2004). though the effect of different management practices (e.g., pot size, substrate, fertilizer supply, and planting density) are reported to greatly affect the physiological quality of tree nursery seedlings (ahmad et al., 2012) effect of potting materials (materials to support the plant growth medium) specially the effect of jute bags on seedling growth is scarcely reported. considering the above facts an attempt has been made in the nursery of bangladesh tea research institute to observe the growth performances of tea saplings raised in the poly and gunny (jute) bags as well as the durability of both types of bags to investigate the potential of the gunny bags to be used in the nursery for raising tea saplings. the experiment was conducted at the main farm nursery of bangladesh tea research institute (btri), srimangal, moulvibazar from january 2005 to january 2006. sixty uniform sized saplings (rooted cuttings) were planted both in poly and gunny bags in each month from january to august in 2005. both types of bags were of the same size (15 cm  23 cm) and contained same plant growth medium i.e. soil. a randomized complete block design with three replications was used in this study where each replicate consisted of 20 bags with one sapling per bag. intercultural operations like watering, manuring, weeding, pest control, and shading were done as and when necessary. data on plant growth parameters were collected on january 2006. therefore, at the time of data collection, the saplings planted in january, february, march, april, may, june, july and august were of 12, 11, 10, 9, 8, 7, 6 and 5 months old, respectively. fifteen plants were selected randomly from each plot to collect data on different parameters under study. all the data were collected separately according to the planting months. the physiological growth parameters studied included plant height, base diameter, number of primary branches and total number of leaves. the fragility (%) of the bags was also roughly noted down based on the visual observation and applied mechanical stress by hand. data were analyzed and means were compared by duncan’s multiple range test (dmrt), using the statistical package mstat (russell, 1994). 110 rana et al. a large variations were observed in the plant height due to the type of bag used (i.e. poly or gunny) to support the plant growth medium and it was observed that gunny bags favored plant growth compared to the poly bags (table 1). heights of the saplings planted in different months were different but the height of the saplings raised in the gunny bags were always higher than the poly bags. the height differences were significant in the saplings planted on january, february, march, june and july. table 1. effect of different types of bag and planting time on the plant height of tea saplings plant height (cm) treatment january february march april may june july august jute bag (t1) 36.00 a 31.40 a 28.20 a 16.20 28.20 29.60 a 19.00 a 15.40 poly bag (t2) 31.40 b 25.80 b 23.60 b 15.40 27.00 27.00 b 14.80 b 15.00 level of significance 0.01 0.01 0.01 ns ns 0.01 0.01 ns cv (%) 9.80 9.25 10.06 31.96 7.82 8.00 13.25 18.84 in a column, figures without letter do not differ significantly by dmrt (p>0.05). base diameter of the saplings planted in january to july were also found higher when raised in the gunny bags than the poly bags and in case of february the differences in diameter were significant (table 2). saplings planted in august showed opposite trend and significantly higher base diameter was obtained when raised in the poly bags. table 2. effect of different types of bag and planting date on the base diameter of tea saplings base diameter (mm) treatment january februar y march april may june july august jute bag (t1) 37.80 38.00 a 34.80 26.20 34.60 32.60 25.80 22.40 b poly bag (t2) 36.00 34.40 b 34.40 24.00 35.00 32.40 25.20 24.40 a level of significance ns 0.01 ns ns ns ns ns 0.05 cv (%) 8.61 8.15 8.91 14.13 8.75 9.51 9.63 11.85 in a column, figures without letter do not differ significantly by dmrt (p>0.05). average numbers of leaves per plant were higher in the saplings raised in the gunny bags than those in the poly bags in most of the planted months, and the differences were significant in the months of february, march, april and july (table 3). similar in base diameter, opposite trend was also observed in the saplings planted in august, and the number of leaves per plant was higher in the saplings raised in the poly bags than those in the gunny bags, though the difference was not significant. table 3. effect of different types of bag on the number of leaves of tea saplings planted different month 111 comparative growth performances of tea saplings raised in the poly and gunny bags number of leaves per sapling treatment januar y februar y march april may june july august jute bag (t1) 12.80 14.40 a 10.60 a 8.40 a 11.60 10.60 8.40 a 7.20 poly bag (t2) 11.60 9.60 b 9.40 b 5.80 b 10.40 11.00 7.00 b 7.40 level of significance ns 0.01 0.05 0.01 ns ns 0.01 ns cv (%) 18.84 17.90 14.78 34.09 17.45 16.93 15.83 20.38 in a column, figures without letter do not differ significantly by dmrt. ns: not significant (p>0.05). no specific trend was obtained due to the use of different types of bags on the generation of primary branches from the tea saplings. among the data, 25% data showed gunny bags favored the generation of primary branches, 25% data showed poly bags favored the generation of primary branches and rest of the data showed non-significant (table 4). therefore, no conclusion could be drawn to understand which type of bag favored the generation of primary branches, and requires further investigation. table 4. effect of different types of bag and planting time on the number of primary branches of tea saplings number of primary branches per sapling treatment january februar y march april may june july august jute bag (t1) 0.13 b 0.60 a 0.13 0.27 0.47 a 0.13 0.07 b 0.13 poly bag (t2) 0.47 a 0.20 b 0.27 0.07 0.13 b 0.33 0.40 a 0.13 level of significance 0.05 0.05 ns ns 0.05 ns 0.05 ns cv (%) 147.29 115.73 204.12 222.97 147.29 182.31 172.45 263.90 in a column, figures without letter do not differ significantly by dmrt (p>0.05). it was observed that the differences in fragility (%) between the poly and gunny bags were significant in all of the planted months (table 5). the fragility of the gunny bags after 6-7 months of planting were so much higher (>33-53%) that the tea saplings may probably be damaged severely during transportation due to the breakage of ‘pindi’ (ball of earth with root system). after the same period (6-7 months) of planting, poly bags showed very low fragility (<4-6%). after 11-12 months of planting, poly bags showed less than 15-18% fragility whereas, the gunny bags after that period were found completely damaged (> 9497% fragility). table 5. flimsiness of the bags (% damage) after different periods of use 112 rana et al. bag damaged (%) treatment january (12 m) februar y (11 m) march (10 m) april (9 m) may (8 m) june (7 m) july (6 m) august (5 m) jute bag (t1) 97.73 a 94.80 a 90.13 a 81.20 a 71.73 a 53.40 a 33.93 a 20.60 a poly bag (t2) 17.40 b 14.87 b 11.93 b 10.20 b 8.27 b 5.80 b 3.53 b 1.87 b level of significance 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 cv (%) 3.69 4.60 4.03 6.95 9.23 11.63 11.35 16.60 in a column, figures bearing dissimilar letters differ significantly. m=months after planting. significant variations in the growth characteristics of the tea saplings raised in the poly and gunny bags. almost all of the studied characters including plant height, base diameter, and number of leaves were found higher in the saplings raised in the gunny bags than those in the poly bags with few exceptions. better growth of the saplings raised in the gunny bags is probably due to the fact that gunny bags provided better aeration to keep the soil granulated that facilitated better root growth. from the weather data of the experimental site it was observed that rainfall started to decline from october and the next two months were rainless with low relative humidity (%). this suggests that poly bags might have helped to preserve more soil moisture than the gunny bags in the next dry spells, and as the root system was not so well developed the condition favored the saplings raised in the poly bags. considering the durability of the bags, it was observed that after about 11-12 months of planting, the gunny bags were completely spoiled but the poly bags were still tolerable to transfer the saplings to the field. as tea saplings/seedlings are required to maintain in the nursery for about 9-12 months and in most of the cases the matured saplings are transported a far away from the nursery, the durability of the bags is considered to be the key issue for determining their potential to be used as a supporting material for the plant growth medium. as the jute bags showed a high degree of fragility after a 6-7 months period of usage, this excludes the possibility of using gunny bags in the tea nursery. this finding urges further research to extend the durability of the gunny bags up to a year to help the planters in raising high quality tea seedling/sapling in the nursery in an eco-friendly manner. based on the study it may be concluded that gunny bag favors the growth of the tea saplings than the poly bag in raising tea sapling in the nursery. however, as tea saplings/seedlings are required to maintain in the nursery for about 9-12 months, low durability (high fragility) of the gunny bags was identified as the key issue that excludes the possibility of using gunny bags in the tea nursery. references ahmed, s. u. 2005. impact of banning polythene bags on floods of dhaka city by applying cvm and remote sensing. environmental health perspectives. 111: 1471-1474. fao. 2015. future fibres: jute. in: food and agriculture organization of the united nations. http://www.fao.org/economic/futurefibres/fibres/jute/en/. accessed 24 october 2015 russell, o. f. 1994. mstat–c v. 2.1 (a computer based data analysis software). crop and soil science department, michigan state university, usa. 113 comparative growth performances of tea saplings raised in the poly and gunny bags villar-salvador, p., r. planelles, e. enrı´ıquez and j. pe˜nuelas rubira. 2004. nursery cultivation regimes, plant functional attributes, and field performance relationships in the mediterranean oak quercus ilex l. for. ecol. manage. 196: 257-266. table 1. weather data of the experimental site for the year 2005 temperature (oc) month mean maximum mean minimum rainfall (mm) rh (%) january 24.97 9.76 0 67.32 february 28.94 14.44 71 58.26 march 30.46 19.29 161 67.33 april 32.80 21.09 239 68.11 may 31.28 21.37 613 77.27 june 33.40 25.40 277 77.68 july 31.98 25.07 357 81.31 august 32.29 25.24 277 80.24 september 32.97 24.75 310 79.92 october 31.75 22.97 109 97.47 november 29.59 15.80 0 73.93 december 28.03 11.96 0 68.99 microsoft word 8. baj-294_revised bangladesh agron. j. 2018, 21(1): 77-81 influence of inorganic and organic fertilizers on growth and yield of soybean a. mamia1*, a.k.m.r. amin1, t.s. roy1 and g. m. faruk2 1 department of agronomy sher-e-bangla agricultural university, dhaka-1207,bangladesh 2deputy secretary, ministry of health and family welfare *corresponding author, e-mail:mamiamoli@gmail.com (received: 14 december 2017, accepted: 06 october 2018) keywords: soybean, growth, yield, fertilizer, biofertilizer, poultry litter, vermicompost abstract the experiment was executed at the agronomy researchfield of sher-e-bangla agricultural university, dhaka-1207, during the period from november, 2015 to march, 2016 to study the effects of fertilizer management of different combinations of inorganic and organic fertilizers on growth, yield attributes and yield of soybean (var. bari soybean 6). the treatment combinations weret0= control, t1= fertilization at recommended fertilizer dose (rfd urea 50 kg ha-1, tsp 150 kg ha-1, mop 100 kgha-1, gypsum 80 kg ha-1 and boron 500 kg ha-1), t2= bio-fertilizer + 50% rfd, t3= biofertilizer + 75% rfd, t4= mixed fertilizer + 50% rfd, t5= mixed fertilizer + 75% rfd, t6= vermi-compost + 50% rfd, t7= vermicompost + 75% rfd, t8= poultry litter + 50% rfd and t9= poultry litter + 75% rfd. results indicated that application of fertilizer at recommended dose, vermi-compost + 75% rfd and poultry litter + 75% rfd produced higher grain yield 2053, 2073 and 2166 kg ha-1, respectively over control. it was also observed thatconsidering the sustainable yield and environment friendly,poultry litter + 75% rfd (t9) and vermi-compost + 75% rfd (t7) couldbe promising for soybean cultivation. introduction proper fertilization is one of the major factors to gain higher yield but injudicious application of inorganic fertilizers without organic supplements causes environmental pollution, damaging soil physical, chemical and biological properties. soybean (glycine max l. merrill) is one of the most economic and nutritious crop in the world with high protein content, excellent source of both oil and protein supplement (mondal et al., 2002). in bangladesh soybean is mostly used as poultry and fish feed. its demand is increasing with the increases of poultry and fish industries. in bangladesh area coverage of soyabean is 60,893 ha and the annual production is 112,024 tons with an averageyield is 1.83 t ha-1 (faostat, 2014) which is very low to meet the increasing demand. therefore, a huge quantity of soyabean is importing every year at the cost of substantial amount of hard currency. use of organic manure alone or in combination of chemical will help to improve physio-chemical properties of soils providing a good substrate for the growth of microorganisms maintaining a favorable nutritional balance.one such strategy to maintain soil fertility for sustainable production of soyabean is through judicious use of fertilizers provided to be responsible for higher yield and with reduced fertilizer pollution (bobde et al., 1998) coupled with organic resources to achieve sustainability in production, where the use of organic manures alone is not sufficient (prasad, 1996). it has also been brought out that the use of organic manures in integration with fertilizers meets the needof micronutrients of soybean (joshi et al., 2000). some symbiotic n2 fixing rhizobium stains fix atmospheric nitrogen (n) in the nodules and show an antagonistic effect against soil borne pathogens (ganesan et al., 2007) and thus it enriches the soil fertility (mahabal, 1986).b. 78 mamia et al. japonicum can fix about 300 kg ha-1 year-1 in symbiosis with soyabean (keser and li, 1992). vermi-compost contains most nutrients in the available forms such as nitrates, phosphates, exchangeable calcium and soluble potassium that have vital role for plants (arancon et al., 2005). applications of vermicompost or poultry litter singly or in combination with other inorganic fertilizerhave been proved effective to enhance growth and yield of soybean (javed and panwar, 2013; chiezey and odunze, 2009). trails with poultry litter on the performance of soyabean are few. as such the present study was undertaken to investigate the effects of different combinations of inorganic and organic fertilizers on growth performances, yield attributes and yield of soybean. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university (sau). it is situated at 23074' north latitude. the land was medium high and soil texture was silty clay with ph 6.1.the treatments of the experiment were as follows: t0: control (without fertilizer),t1: recommended fertilizer dose (rfd), t2: bio-fertilizer + 50% rfd , t3: biofertilizer + 75% rfd, t4: mixed fertilizer + 50% rfd, t5: mixed fertilizer + 75% rfd, t6: vermi-compost + 50% rfd, t7: vermi-compost + 75% rfd, t8: poultry litter + 50% rfd and t9: poultry litter + 75% rfd. the experiment was laid out in randomized complete block design with 3 replications. the size of unit plot was 3m×2m. distance maintained between replication and plots were 1.0m and 0.75m, respectively. well rotten poultry litter and vermicompost were applied @ 10 and 2 t ha-1, respectively before final land preparation according to treatment. the recommended inorganic fertilizer dose used for soybean was 50-150-100-80-0.5 kg ha-1 as urea, tsp, mp, gypsum and boric acid, respectively. full amount of all fertilizers as per treatment applied during final land preparation as basal dose. seeds of the var, bari soybean-6 was sown on 25 november, 2015 in lines distance of 30 cm and plant to plant 5-6 cm. a light irrigation was given before sowing seed. first, second and third irrigation was given on 20, 35 and 56 days after sowing. the crop was protected from insects and ants through the application of babiston 250wp on seed line. at different stages of crop growth (30, 45, 60, 75 das and at harvest), the height of five randomly selected plants from each plot were collected and sampled and data on plant height, dry weight of plant as well as yield contributing characters were recorded. the crop was harvested on 15 may, 2016. grain yield was adjusted to 12% moisture content. the obtained data for different characters were statistically analyzed with the computer based software mstat-c and the difference among treatment means were estimated by the least significant difference (lsd) test at 5% level of probability (gomez and gomez, 1984). results and discussion plant height of soybean varied significantly at 30, 45, 60, 75 das and at harvest for different combinations of inorganic and organic fertilizer (table 1). results of plant height showed increasing trend with the increases of growth stages and the highest increase was found at harvest. on the other hand, combination of fertilizers applied plots increased plant height over control for all sampling dates. different combinations of inorganic and organic fertilizers showed significant variation for dry weight plant-1 at 30, 45, 60, 75 das and at harvest (table 2). result revealed that dry matter weight increased significantly with inorganic and organic fertilizers combination treatment over control. among the combinations. treatment t1 showed maximum dry weight followed by t9 than other combinations for all sampling dates.this might be due to optimum and continuous supply and availability of nutrients through organic source which help in better uptake of nutrient that ultimately enhancing cell division and thereby increased all the growth attributes. these findings are in accordance with the results of patil and udmale (2016).the maximum seed yield was recorded from t9 (2166 kg ha-1), which was influence of inorganic and organic fertilizers 79 statistically at par with t7 and t1, respectively for 2073 and 2053 kg ha-1). on the other hand, the lowest yield was found in t0 (1185 kg ha-1). the result revealed that treatment t9, t7 and t1 produced 82.78%, 74.94% and 73.25% higher yield over control (t0). the maximum grain yield might be attributed to maximum dry matter weight plant-1, number of pods plant-1, seeds plant-1 and 100seed weight. this might be due to adequate supply of nutrient element at the right time from organic and inorganic sources which helped optimum dry matter partitioning from the source to sink during reproductive stage of plant consequently increase the seed yield of soybean. the result corroborates with the findings of falodun et al. (2015). table 1. effect of inorganic and organic fertilizerson plant height of soybean at different days after sowing treatment plant height (cm) at different days after sowing 30 45 60 75 at harvest t0 20.73 b 33.07 b 40.21 b 48.13 d 45.80 b t1 21.57 ab 40.83 a 52.55 a 54.80 ab 52.72 a t2 21.13 ab 39.20 a 48.87 a 50.73 b-d 49.05 ab t3 21.15 ab 37.80 a 49.48 a 51.07 b-d 47.80 ab t4 20.55 b 37.73 a 50.62 a 51.27 b-d 47.52 ab t5 21.27 ab 39.40 a 49.97 a 54.13 a-c 51.03 ab t6 21.54 ab 39.27 a 51.29 a 52.27 a-d 50.37 ab t7 20.35 b 39.67 a 52.15 a 55.53 a 51.83 a t8 21.20 ab 37.87 a 51.47 a 49.93 cd 47.85 ab t9 23.23 a 39.47 a 51.79 a 52.27 a-d 51.60 a lsd (0.05) 2.33 4.43 3.87 4.21 5.43 cv (%) 6.39 6.72 4.53 4.72 6.39 table 3. effect of organic and inorganic fertilizers on dry weight plant-1 of soybean at different days after sowing treatments dry weight plant-1 (g) at different days after sowing 30 45 60 75 at harvest t0 0.27 c 1.33 f 3.20 e 4.67 f 5.33 f t1 0.43 b 2.22 a 5.33 a 7.17 ab 9.21 a t2 0.43 b 1.45 f 3.77 c-e 4.87 ef 5.67 f t3 0.42 b 1.78 c-e 3.33 de 5.50 d-f 6.83 de t4 0.46 ab 1.69 de 4.16 bc 6.53 bc 6.67 e t5 0.42 b 1.86 b-d 4.67 ab 6.53 bc 8.17 bc t6 0.50 a 1.56 ef 4.00 b-d 5.62 c-e 7.15 de t7 0.41 b 2.06 ab 5.00 a 6.17 cd 8.83 ab t8 0.30 c 1.56 ef 4.22 bc 6.07 cd 7.53 cd t9 0.42 b 2.01 a-c 5.15 a 7.53 a 8.93 ab lsd (0.05) 0.05 0.24 0.69 0.95 0.80 cv (%) 7.99 8.13 9.46 9.11 6.27 table 4. effect of organic and inorganic fertilizers on pods plant-1, seeds pod-1, pod length, 1000-seed weight, grain yield and stover yield of soybean treatment pods plant-1 (no.) seeds pod-1 (no.) pod length (cm) 1000-seed wt. (g) seed yield (kg ha-1) stover yield (kg ha -1) t0 19.00 d 2.17 bc 3.290 b 10.45 1185 d 1552 c t1 26.20 a 2.63 a 3.850 a 11.74 2053 a 2464 a t2 19.73 cd 2.43 a-c 3.727 ab 10.53 1511 c 1777 bc t3 19.80 b-d 2.40 a-c 3.740 ab 10.66 1624 bc 1814 b t4 20.60 b-d 2.47 ab 3.673 ab 10.14 1610 bc 1828 b t5 20.80 b-d 2.57 a 3.810 a 10.79 1786 b 1951 b t6 22.07 b-d 2.45 ab 3.680 ab 10.88 1694 bc 1904 b 80 mamia et al. t7 23.13 ab 2.08 c 3.750 ab 11.36 2073 a 2278 a t8 22.60 bc 2.57 a 3.780 a 10.97 1768 b 1977 b t9 26.47 a 2.67 a 3.847 a 11.65 2166 a 2372 a lsd (0.05) 3.35 0.36 0.48 ns 221.80 254.30 cv (%) 8.86 8.72 7.58 8.54 7.4 6.21 here, t0= control, t1= fertilizer at recommended dose (rfdurea: 50 kg ha-1, tsp: 150 kg ha-1, mp: 100 kg ha-1, gypsum: 80 kg ha-1 and boron: 500 g ha-1), t2= biofertilizer + 50% rfd, t3= biofertilizer + 75% rfd, t4= mixed fertilizer + 50% rfd, t5= mixed fertilizer + 75% rfd, t6= vermicompost + 50% rfd, t7= vermicompost + 75% rfd, t8= poultry litter + 50% rfd and t9= poultry litter + 75% rfd. the maximum stover yield was observed in t1 (2464 kg ha-1), which was statistically at par with t9 and t7 (2372 and 2278 kg ha-1, respectively). again the lowest stover yield was recorded fromt0 (1552 kg ha-1) which was statistically at par with t2 (1777 kg ha-1). the result agrees with the findings of khaim et al. (2013). dikshit and khatik (2008) observed that application of organic and inorganic fertilizers increased the stover yield of soybean. conclusion it may be concluded from the present study that inorganic fertilizer at recommended dose, vermicomost + 75% rfd and poultry litter + 75% rfd showed the better performance on growth and yield contributing characters of soybean. but considering the yield and sound environment, vermicomost + 75% rfd and poultry litter + 75% rfd could be used instead of inorganic fertilizer without significantly yield reduction. poultry litter + 75% rfd and vermicomost + 75% rfd may be environment friendly management for higher soybean yield. references arancon, n.q., c.a. edwards, p. bierman, metzger, j.d. and c. lucht. 2005. effects of vermicompost produced from cattle manure, food waste and paper waste on the growth and yield of peppers in the field. pedobiologia. 49: 297-306. bobde,g.n., r.m. deshpande, d.m. khandalker. and v.l. turankar. 1998. nutrient management of soybean. indian j. agron. 43: 390-392. chiezey, u.f. and a.c. odunze. 2009. soybean response to application of poultry manure and phosphorus fertilizer in the sub-humid savanna of nigeria. j. ecol. nat. environ. 1(2): 2531. falodun, e.j., j.o. ehigiator. and s.a. ogedegbe. 2015. growth and yield response of soyabean (glycine max merr.) to organic and inorganic fertilizer in edo rainforest of nigeria. american j. plant sci. 6: 3293-3297. fao stat. 2014. available at http://faostat.fao.org/. ganesan, s., k.r. ganesh. and r. sekar. 2007. integrated management of stem rot disease arachis hypogaeal using rhizobium and trichoderma harzianum. biores. technol. 2:396-403. gomez, k. a. and a.a. gomez. 1984. statistical procedure for agricultural research (2nd edn.). intl. rice res. inst. a willey. intl. sci. pub. pp. 28-192. javed, s. and a. panwar. 2013. effect of biofertilizer, vermicompost and chemical fertilizer on different biochemical parameters of glycine max and vigna mungo. recent res. sci. technol.5: 40-44. joshi, o.p., s.d. billore. and a. ramesh. 2000. integrated micronutrient management in soybean. j. oilseed res. 17: 370-372. influence of inorganic and organic fertilizers 81 keser, h. h. and f. li. 1992. potential for increasing biological nitrogen fixation in soybean. plant soil. 141: 131-135. khaim, s., m.a.h. chowdhury. and b.k. saha. 2013. organic and inorganic fertilization on the yield and quality of soybean. j. bangladesh agril. univ. 11(1): 23-28. mahabal, r.1986. high yielding varieties of crops. all indian co-coordinated barley improvement project, iari regional station kamal (haryana). p. 641. patil, h.m. and k.b. udmale. 2016. response of different organic inputs on growth and yield of soybean on inceptisol. scholarly j. agril. sci.6(5): 139-144. prasad, r. 1996. cropping systems and sustainability of agriculture. indian farming.46:39-45. bangladesh agron. j. 2014, 17(1): 89-94 variations in salinity tolerance of selected mango rootstocks r. k. roy1, m. robbani2, m. ali2, s. k. bhowal3*, a. n. m. erfan4 1& 4m.s. student in horticulture, patuakhali science and technology university, bangladesh 2professor, department of horticulture, patuakhali science and technology university, bangladesh 3scientific officer (agronomy), on-farm research division, bangladesh agricultural research ins., noakhali, bangladesh *corresponding author: shamal.bau@gmail.com key words: mango rootstock, salinity tolerance abstract an experiment was conducted at the germplasm centre, department of horticulture, patuakhali science and technology university (pstu) during the period from july 2011 to march 2013 to study the performance of selected mango rootstocks in the saline area in bangladesh. the experiment consisted of four mango rootstock lines collected from rangpur, dumki, khulna and kuakata, and five salinity treatments namely control (0 dsm-1), low (4 dsm-1), medium (6 dsm-1), high (8 dsm-1) and very high (10 dsm-1). a two factor experiment was conducted in a randomized complete block design (factorial) with four replications. results revealed that rootstock line and salinity levels had significant influences on various crop characters viz. length of rootstocks, diameter of rootstocks, number of leaves and percent rootstocks success and survivability. in case of rootstocks, the longest rootstock length (41.38 cm), highest number of leaves (37.58) and survivability (71.73%) were recorded in rangpur line. in case of salinity treatments, rootstock diameter (16.09 mm), number of leaves/graft (36.47) and survivability (67.37%) were recorded in low salinity treatment. interaction of rootstock lines and different salinity treatments showed significant variation on the length and diameter of rootstocks at 120 dat. the maximum diameter of rootstock (17.63 mm) was recorded in high (8 dsm-1) salinity treatment in rootstock line of kuakata, followed by the same stages of rootstock lines of khulna (17.56 mm). the longest rootstock (46.75 cm) was recorded in control treatment (0 dsm-1) with rootstock line of rangpur followed by the same stages of rootstock (41.75 cm) with medium salinity treatment (6 dsm-1). rangpur rootstock line performed best from 0-8 dsm-1 salinity. the overall salinity tolerance was graded as follows: rangpur rootstock line > dumki rootstock line > kuakata rootstock line > khulna rootstock line. introduction mango (mangifera indica l.) is one of the most popular and commercially important fruits in bangladesh which is known as the “king of tropical fruits”. it belongs to the family anacardiaceae which is believed to have originated in the eastern india, assam, burma or in the malayan region (mukherjee, 1997). it has been cultivated in this sub-continent from 4000 years ago (candole, 1984). mango is grown in wide geographical area particularly in india, pakistan, brazil, mexico, the philippines, indonesia, thailand and srilanka. in bangladesh mangoes are grown everywhere, but the commercial and good quality grafted mangoes grown in the north-western districts and unknown varieties (seedling mangoes) are grown in the south eastern and other part of the country (bhuyan, 1995). mango ranks third among the tropical fruits grown in the world with the total production of 28848 thousand metric tons (fao, 2002). in bangladesh it ranks first in terms of area and third in production. it occupies an area of about 51.01 thousand hectares, with the production of 243 thousand metric tons of fruits (bbs, 2004). in bangladesh, a general decreasing trend in area and production of mango is observing during 1994-95 to 2003-04 (bbs, 2004). because, about 90% existing mango plants are raised from seeds which are mostly tall in nature with a large canopy (hossain, 1994). thus, it is difficult to incorporate tall and large sized mango varieties in limited area. these are the major reasons of diminishing mango production area. mailto:shamal.bau@gmail.com 90 roy et al. the other reasons behind this are lack of suitable variety (sarder et al., 1995), unavailability of suitable planting materials etc. grafted mango plants are true-to-type, require less area and start bearing earlier than the plants raised from seed. now a day’s using of epicotyle grafting in mango is a practice with good success for rapid multiplication of mango. at present, scion with the same polythene strip is used for graft joint. but research findings on these aspects in bangladesh are very limited or scanty. various factors influence the success and survivability of mango graft, viz. time of operation, grafting method, defoliation period of scion, maturity of stock and scion, wrapping technique of scion, leaf retention on rootstock and variety etc. among these, physiological maturity of stock and scion wood are very important factors for higher success, survivability and growth of grafts (kains and mc question, 1958; brahmachare et al., 1999). the information or research work with mango in saline area of southern belt is very limited. mango production is hampered due to restricted growth of the plant, root expansion hampered, low success and survivability due to high salinity. considering the above facts the present research work was undertaken to study the salinity tolerance of selected mango rootstocks. materials and methods the experiment was conducted at the germplasm centre, department of horticulture, patuakhali science and technology university (pstu), during the period from july 2011 to march 2013. the experimental area was situated under the sub-tropical monsoon climate, which is characterized by high temperature and heavy rainfall during the months of july to september and scantly rainfall associated with moderate low temperature during the rest period of the year. the soil of the experimental area was silty loam in texture belonging to the gangas flood plain of aez 13 having non-calcareous dark grey flood plain soil. the selected area was a medium high land. it was fertile, well drained and slightly acidic with the ph varying from 5.5 to 6.8 (barc, 1989). the experiment consisted of two factors i.e. factor-a: four type of mango rootstocks viz. r1 = rangpur line, r2 = khulna line, r3 = dumki line, r4 = kuakata line and factor-b: five level of soil salinity viz. s0 = control (0 dsm-1), s1 = low (4 dsm-1), s2=medium (6 dsm-1), s3 = high (8 dsm-1), s4 = very high (10 dsm-1). a two factor experiment was conducted in a factorial randomized complete block design with four replications. healthy and heavy stones of mango fruits of unknown cultivars were collected and placed in a bucket of water. only those stones that sunk and touched the bottom of bucket (containing water) were selected. about 1000 stones were selected for this process, which were uniform in size and shape. the stones were placed in polybags containing a mixture of soil and cowdung at the ratio of 1:1. one stone was placed in one polybag. after placing the seeds were germinated within 15 to 30 days. the experimental pots were made by earthen, containing 2-3 aeration holes at bottom for removal of excess water. total 480 experimental pots were filled by soil; well decompose cowdung, sand & small pitches of broken stones at the ratio of 1:1:1:1. nearly one and a half year mango rootstocks collected from four different types of mango cultivar which were raised in polybags previously & transplanted to the experimental pots. the healthy, vigorous, uniform in size and growth, pest and disease free rootstocks was selected for the experiment. pots containing healthy and uniform size rootstocks were raised in each rootstock line. intercultural operations like irrigation, weeding, application of fertilizer, spraying of insecticides and fungicide were given whenever needed for the good health of stock plant. four different rootstock lines were collected from rangpur, dumki, kuakata and khulna region. at first rootstocks were separated from different types of rootstock by their proper identity through individual tagging. four rootstock lines were arranged according to their identical number for properly data collection as well as performance review of different rootstock lines. all necessary measures were adopted to make the pot free from weeds and create a favorable environment to ensure proper growth and development of grafted plants. weeding and mulching were done whenever necessary during the period of investigation. the channels, made around each pot were connected to the main drain for rapid removal of excess rain water. proper shades were provided with the help of bamboo and coconut leaf until the grafts were in good condition in growth. sometimes the shade was removed to 91 salinity tolerance of mango rootstocks expose the plant to the direct sunlight for their proper growth. as a preventive measure against insect, pest and disease, spraying with insecticide and fungicides were done following a routine schedule. for this, diazinon and diathane m-45 @ 2ml liter-1 of water were applied at 7-10 days interval from 2-3 weeks after grafting and continued up to the last date of recording final data. the means of all the treatments were calculated and compared by least significant difference (lsd) test at 5% level of probability (gomez and gomez, 1984). results and discussion effect of rootstock significant variation was noticed in the growth of rootstocks from 30 to 120 days after transplanting (table 1). at 30 das, rangpur and khulna rootstock was similar and higher than the rest. similar trend was recorded at 60 dat and 90 dat. there was trend to increase length with the advancement of days. the longest length of rootstock was found in rangpur rootstock line (41.38 cm) while the shortest length of rootstock found in kuakata rootstock line (34.25 cm) at 120 days after transplanting. significant variation was also noticed in the number of new leaves from 30 to 120 days after transplanting (table 1). number of leaves showed maximum at khulna line followed by rangpur at 30 dat. similar trend was found at 60 and 90 dat but there were no significant difference at 90 and 120 dat. after initial success, the rootstocks were observed for 120 days, some rootstock died during this period. at the end of 120 days, the percentage of rootstock survival was recorded and the percentage of rootstock survival was presented in table 1. the highest rootstock survival (71.73%) was obtained from rangpur rootstock line while other rootstock survivability among the lines were similar. table 1. main effect of rootstock lines on the length of rootstocks, leaves number and rootstock survivability at different days after transplanting rootstock line rootstock length (cm) no. of leaves rootstock survivability at 120 dat (%) 30 days 60 days 90 days 120 days 30 days 60 days 90 days 120 days rangpur 39.50a 40.10a 40.53a 41.38a 22.38ab 24.85ab 31.77 37.58 71.73a dumki 32.95b 33.40b 33.78b 34.63b 15.99b 19.80b 24.27 27.02 60.90b khulna 36.67a 36.97ab 37.28ab 37.97ab 25.33a 28.35a 31.52 33.70 57.39b kuakata 32.90b 33.25b 33.58b 34.25b 16.05b 18.42b 25.08 28.40 56.73b lsd(0.05) 3.57 3.74 3.72 3.74 8.014 8.24 ns ns 4.89 cv (%) 7.18 7.42 7.31 7.20 28.71 25.75 26.85 23.91 5.66 effect of salinity significant variation was found among different salinity treatments in the present experiment (table 2). there was no significant difference in salinity treatment at 30 dat except very high salinity level. similar trend was followed upto 120 dat. but maximum length of rootstock (39.72 cm) was recorded at high salinity level while shortest rootstock (33.81 cm) was observed in very high (10 dsm-1) salinity treatment at 120 dat (table 2). very high salinity treatment lowered the water potential of the roots, and this caused quick reductions in growth rate along with a suite of metabolic changes identical to those caused by water stress. the effect of salinity treatments on the diameter of rootstocks has been shown in the fig. 1. significant variation was found different salinity treatments. after 120 dat, high salinity treatments was found maximum diameter of rootstock (16.09 mm) while the lowest diameter of rootstock in very high (10 dsm-1) salinity treatment (13.52 mm) (fig. 1). significant variation was found different salinity treatments on the rootstock survivability in the experiment but number of leaves plant-1 was not significantly influenced by salinity treatment. rootstock survivability (%) was minimum at low level of 92 roy et al. salinity followed by control. srivastava et al. (1989) also reported that increases the salinity treatment decreases the rate of survivability of mango. table 2. main effect salinity treatment on the length of rootstocks, leaves number and rootstock survivability at different days after transplanting salinity treatment rootstock length (cm) no. of leaves rootstock survivability (%) 30 days 60 days 90 days 120 days 30 days 60 days 90 days 120 days control 34.91ab 35.59ab 35.91ab 36.78ab 19.44 23.22 28.78 32.81 64.77ab low 36.97a 37.34a 37.72a 38.47a 20.56 24.09 33.09 36.47 67.37a medium 35.06ab 35.44ab 35.91ab 36.50ab 17.59 20.56 25.69 28.66 60.69bc high 38.13a 38.59a 38.91a 39.72a 21.61 24.72 28.06 31.25 59.64c very high 32.47b 32.69b 33.00b 33.81b 20.47 21.69 25.19 29.19 55.97c lsd(0.05) 3.57 3.74 3.72 3.74 ns ns ns ns 4.89 cv (%) 7.18 7.42 7.31 7.20 28.71 25.75 26.85 23.91 5.66 control= 0 dsm-1, low= 4dsm-1, medium = 6 dsm-1, high =8 dsm-1, very high =10dsm-1 fig. 1. effect of salinity treatments on the diameter of rootstocks at different days after transplanting interaction effect of rootstocks and salinity interaction of rootstock lines and different salinity treatments showed significant variation on the length of rootstocks at 120 dat (fig. 2). the periodical data showed that more increase in length of rootstocks recorded at 120 dat. the longest rootstock (46.75 cm) was recorded when control salinity treatment (0 dsm-1) with rootstock line of rangpur followed by the same stages of rootstock (41.75 cm) with medium salinity treatment (6 dsm-1). the shortest rootstock (29.88 cm) was recorded in the rootstock line of kuakata with very high salinity (10 dsm-1) treatment (fig. 2). 93 salinity tolerance of mango rootstocks fig. 2. interaction of rootstocks and salinity treatments on the rootstock length at different dat interaction of rootstock lines and salinity treatment had significant influence on the diameter of rootstock at 120 dat (fig. 3). there was trend to increase rootstock diameter with the advancement of days 30 to 120 dat. the maximum diameter of rootstock (17.63 mm) was recorded in high (8 dsm-1) salinity treatment into the rootstock line of kuakata, followed by the same stages of rootstock lines of khulna (17.56 mm) with high salinity treatment (fig. 3). the minimum diameter (12.38 mm) of rootstock line of dumki was recorded with very high (10 dsm-1) salinity treatment. fig. 3. interaction of rootstocks and salinity treatments on the diameter of rootstock at different dat references barc. 1989. fertilizer recommendation guide. bangladesh agriculture research concil, new airport road, farmgate, dhaka-1207. pp.11-41. bbs. 2004. monthly statistical bulletin, bangladesh bureau of statistics, statistics division, ministry of planning, government of the people’s republic of bangladesh. dhaka, p.49. brahmachari, v. s., a. r. singh and r. c. bishwas. 1999. effect of period of defoliation of scion and age of rootstock on success of epicotyl grafting in mango (mangifera indica l.) cv. amrapali. orissa j. hort. 27: 1-4. 94 roy et al. bhuyan, m. a. j. 1995. mango. in: fruit production manual, horticulture research and development project, dae-padc. p.197. candole, a. d. 1984. origin of cultivated plants. vegal paul trench and co., london pp.1-67. fao. 2002. production yearbook. statistical series no. 163. food and agriculture organization, rome, italy, p.182. hossain, a. k. m. a. 1994. production technology of mango. horticulture research centre, bari, joydebpur, gazipur. l22p. kains, m. g. and m. mcquestion. 1958. propagation of plants. grage judd publishing company, inc., new york. p.225. mukherjee, k. u. 1997. introduction: botany and importance. in: the mango: botany, production and uses. 1st edition (r. & litz ed.), cab international, wallingford, uk. pp.1-19. sarder, p. k., d. guha and m. a. uddin. 1995. assessment of introduced mango germplasm under bangladesh condition. annual report on mango improvement, regional horticulture research station, bari, nawabganj-6300, bangladesh. p.10. srivastava, k. c., n. p. singh, m. s. rajput, g. c. sinha and b. lai. 1989. performance of mango plants raised by different methods. acta hort. 231: 209297. chapter iv bangladesh agron. j. 2015, 18(2): 1-8 influence of nitrogen and phosphorus on yield and seed quality of french bean s.s.kakon1, md. s.u. bhuiyan2 and s.m. a. hossain2 1agronomy division, bangladesh agricultural research institute, gazipur-1701 2department of agronomy, bangladesh agricultural university, mymensingh-2200 corresponding author: kakonbari@gmail.com key words: french bean, pod set, yield and seed quality abstract the experiment was conducted at the research field of agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur during rabi (winter) season of 2010-11 to 2011-12 to determine the optimum rate of nitrogen and phosphorus fertilizer on yield and seed quality of french bean. a randomized complete block design was followed with ten treatment combinations such as n0p0, n0 p44, n50 p44, n100 p44, n150 p44, n200 p44, n150p0, n150p22, n150p33 and n150p55. number of pods and yield of french bean were significantly increased with the increase in n (150) and p (44) kg ha--1. averaged over the years, maximum number of pod (9.45 plant-1) and seed yield (1563.33 kg ha-1) were obtained when n and p were applied at the rate of 150 and 44 kg ha-1, respectively while lowest yield to n0p0 treatment in both the years. the treatment (n150p44 kg ha-1) gave the highest seed yield which was 51.4 and 54.30% higher than the control. quality in terms of germination percentage and vigour index of harvested seed was also significantly influenced by higher doses of n and p while the lowest seed quality from plants that received no fertilizer in both the years. introduction french bean (phaseolus vulgaris l.) is a dual purpose crop grown as a pulse and vegetable crop. its dry seeds are very nutritious containing about 24.9% protein, 60.1% carbohydrate, fat, thiamin, riboflavin, ca, fe and niacin as well as fibre (pierce, 1987; rashid, 1999 including leguminous crop like french bean could improved cropping system as well as improve soil fertility. recently cultivation of french bean is gaining popularity in bangladesh because of its high nutritive value, good taste and wide range of use and also export purpose. but its yield is low compared to other french bean producing countries of the world due to lack of improved cultivars, balanced nutrition and cultural practices. unlike other pulses, french bean is inefficient in symbiotic nitrogen fixation (ali and lal, 1992) as it lacks nodulation due to the absence of nod gene regulator (kushwaha, 1994). as nodulation is poor in french bean, it requires more n and p for root development, nodulation and better plant growth (ssali and keya, 1986). phosphorus not only enhances the root growth but also promotes early plant maturity (mullins et al., 1996). reddy et al. (2010) also reported that increased nitrogen levels from 75 to 150 kg ha-1 improved the yield attributes and seed yield (520 kg ha-1) over 125, 100, 75 kg n ha-1, respectively. padrit et al. (1996) found that phosphorus application to the seed crop of peas had improved seed vigour. rao et al., (1983) observed that plants deficient in phosphorus produce seeds having slower germination than normal seed. french bean seed yield and quality can be enhanced by adopting improved agronomic practices, particularly by applying balanced nutrition to the crop. the present investigation was, therefore, carried out to determine the 2 kakon et al. optimum level of nitrogen and phosphorus fertilizer for exploiting the yield potential and seed quality of french bean. materials and methods the experiment was conducted at agronomy research field of bangladesh agricultural research institute (bari), gazipur, bangladesh during november to april during 2010-11 and 2011-12. the experiment site was located chhiata series under agro-ecological zone28 (aez-28) of 23059' n and 90024' e. the rainfall during the experimental period was 42.0 mm in the first year and 189 mm in the second year. the soil of the experimental field was loamy in texture, low in organic matter (1.27%), acidic in nature with ph (6.1) and contained very low amount of total nitrogen (0.067%), phosphorus (9.6%), sulphur (12%), zinc (2 meq 100g -1) and medium amount of potassium (0.18 meq 100g -1). the experiment was laid out in a randomized complete block design (rcbd) with three replications. the unit plot size was 4.8 m × 3.0 m. there were ten treatment combinations such as n0p0, n0 p44, n50 p44, n100 p44, n150 p44, n200 p44, n150p0, n150p22, n150p33 and n150p55. the source of n was urea and that of p was triple super phosphate. other fertilizers were muriate of potash, gypsum and zinc sulphate, respectively. the total amount of tsp, muriate of potash, gypsum, zinc sulphate and 50% of urea were mixed with the soil during final land preparation and the rest urea was top dressed at 35 days after sowing (das). the seeds of french bean var. bari jharsheem-1 were sown on 25 november, 2010 and 2011, respectively. seeds were treated with vitavax and sown continuously in 30 cm apart with plant distance 15 cm. weeding was done at 25 and 40 das. for uniform germination, a light irrigation was given by sprinkler method after sowing of seeds. three irrigations were given at 25, 40 and 60 das. the yield component data were collected from 10 randomly selected plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise and seeds were separated from the pods manually. the standard germination test was conducted following ista, 1996 rules. seed vigour index was calculated by multiplying percent and seedling length. the protein content was calculated by multiplying the nitrogen content (%) in seeds by 6.25. data on all the parameters were analyzed statistically with the help of a computer package programme mstat -c and means were separated using dmrt. results and discussion yield and yield contributing characters the effects of n and p fertilizer application on yield and yield contributing characters of french bean in both the years (table 1). plant receiving more nitrogen prolonged duration to complete vegetative growth, which resulted longer time of flowering, as similar to kaisar et al. (2007). the number of flowers plant-1 and pods plant-1 significantly increased with the increasing levels of n. plants treated with 200 kg n ha-1 produced maximum number of flowers plant-1 followed by 150 kg n ha-1. plants grown in p treated plots recorded significantly higher number of flowers plant-1 over control. plants treated with 150 kg n ha-1 produced maximum number of pods plant-1 which was statistically similar to 100 kg n. number of pods plant-1 increased due to sufficient supply of n for better growth of plant which might have led to higher photosynthesis and the development of higher number of pod bearing branches (reddy et al., 2010; prajapati et al., 2003). percentage of abscission was slightly reduced by the application of n and p but the variations were not consistent with the level of n and p application in both the years (table 1). saha (2003) reported that plants supplied with adequate mineral n had a greater flower number but less pod set. 3 influence of nitrogen and phosphorus on yield and seed quality of french bean the maximum seed size was observed in the plants grown with 150 kg n ha-1 which was statistically similar to 100 and 200 kg n ha-1 . application of 44 kg p gave the highest 100seed weight which was at par with that of 22 and 55 kg p ha-1 while smallest seeds from control plot. averaged over the years significantly the highest seed yield was recorded in 150 kg n and 44 p kg ha-1 due to higher number of pods plant-1 and 100-seed weight. the increase in yield might be due to increased availability of nitrogen and phosphorus, causing accelerated photosynthetic rate leading to more production of carbohydrates and improvement in growth and yield attributes. these results agree with the findings of singh, 2000; and reddy et al., 2010. further increase of n and p fertilizers tended to decrease the seed yield there was positive linear relationship between pods plant-1 and seed yield (fig.1 and 2) indicating that 97 and 96% of total variation in seed yield of french bean could be explained by the linear function in pods plant-1 in both the years. application of n fertilizer generally increased seed yield over n control but the yield response was not linear. likewise increase in seed yield was observed up to 44 p kg ha-1 and further increment seed yield was not increased due to the over growth of the plants. from the regression analysis it is observed that seed yield was related with the n and p levels following a quadratic relationship (fig. 3 and 4) averaged over years. from the quadratic regression, y= -0.026 n2 + 9.33n + 684.7, it is estimated that 178 kg n ha-1 is optimum dose for getting maximum seed yield of french bean. srinivas and naik (1990) reported optimum dose to be 125.6 kg ha-1 for french bean production while nitrogen was applied up to 160 kg ha-1 in their field trial. the response of seed yield to phosphorus was quadratic in nature and from the regression equation, y= -0.141p2 + 13.81p + 1356, the estimated optimum levels for getting maximum seed yield was 48.97 kg p ha-1. seed yield was positively correlated with growth parameters and yield contributing characters viz., total dry matter production plant-1 at harvest (0.953), number of pods plant-1 (0.986) and 100-seed weight (0. 981). table 1. seed yield and yield components of french bean as affected by levels of nitrogen and phosphorus fertilizer during 2010-11 and 2011-12 flowers plant-1 (no.) pod plant-1 (no.) 100-seed weight (g) seed yield (kg ha-1) treatments 2010-11 2011-12 2010-11 2011-12 2010-11 2011-12 2010-11 2011-12 n0p0 24.67e 26.67f 4.59e 4.72e 18.74c 17.93d 682.16f 673.02e n0 p44 27.67e 32.00d-f 5.17de 5.13e 19.17c 19.29cd 750.12ef 723.58e n50 p44 34.17d 35.33c-e 6.33c-e 5.82de 21.15b 20.51bc 956.79de 981.98d n100 p44 38.17 bc 41.00bc 8.08a-c 7.87a-c 23.06a 22.73ab 1375.12a-c 1413.15a-c n150 p44 41.33 ab 45.03ab 9.28a 9.62a 23.38a 23.14a 1543.33a 1583.33a n200 p44 44.33a 50.00a 9.07a 9.23ab 21.83ab 22.13ab 1451.67ab 1479.63ab n150p0 25.67e 30.43ef 6.68b-d 7.06cd 21.12b 20.87a-c 1158.27cd 1206.36c n150p22 35.67cd 38.40b-d 7.53a-c 7.62bc 22.41ab 22.07ab 1259.75bc 1314.38bc n150p33 38.33bc 41.33bc 8.50ab 8.71a-c 22.76a 22.20ab 1495.00ab 1536.90ab n150p55 41.00ab 43.87ab 8.35ab 8.62a-c 22.16ab 21.83ab 1420.00a-c 1460.00ab cv (%) 4.65 6.83 10.13 9.31 2.89 4.51 8.88 7.25 ns = not significant, cv = co efficient of variation. in a column, figures having common letter(s) do not differ significantly at 1% level by dmrt 4 kakon et al. fig.1 relationship between pods plant -1 (no.) and seed yield as affected by nitrogen level averaged over years. y = 185.38x 175.61 r 2 = 0.9729 0 200 400 600 800 1000 1200 1400 1600 1800 0.00 2.00 4.00 6.00 8.00 10.00 no. of pods plant -1 se ed y ie ld k g ha -1 5 influence of nitrogen and phosphorus on yield and seed quality of french bean 6 kakon et al. seed quality the highest germination was obtained in plants which received n150p44 kg ha-1 while the lowest seed germination from plants that received no fertilizer. application of n rates exerted a continuous significant increase in the percent germination up to 150 kg n ha-1 over 50 and 100 kg n ha-1. beyond this decreased germination (%) received 200 n kg ha-1. phosphorus exerted a significant influence on seed germination up to 22 kg ha-1 over control (table 2). significant increase in seed quality parameters was due to increase in 100seed weight which in turn might have supplied adequate food reserves during germination and resulting in exhibiting of higher seedling vigour. vigour index the best quality in respect of seedling vigour index was recorded with t 200 n but at par to 150 kg n ha-1 while control plot produced the lowest seedling vigour index. similar results were reported by saha (2003). the maximum seedling vigour indexes were recorded from 55 kg p ha-1 and it was at par with that of 22 kg and 33 kg p ha-1. table 2. effects of different levels of nitrogen and phosphorus fertilizers on seed quality of french bean during 2010-11 and 2011-12 germination (%) vigour index protein (%)n and p levels 2010-11 2011-12 2010-11 2011-12 2010-11 2011-12 n0p0 88.0b 81.00e 2192.63e 1872.00d 20.77e 21.02d n0 p44 90.5ab 84.33de 2364.52c-e 2003.80cd 21.25de 21.54cd n50 p44 92.5ab 89.67b-d 2572.85b-d 2192.13bc 22.08cd 22.40b-d n100 p44 95.17a 92.33a-c 2785.92b 2310.23b 22.94a-c 23.17a-c n150 p44 95.5a 96.58a 3120.02a 2678.27a 23.65a 23.85ab n200 p44 93.2ab 95.33ab 3150.53a 2860.27a 23.96a 24.04a n150p0 88.83b 86.67c-e 2256.73de 2061.77b-d 22.71bc 22.75a-c n150p22 90.33ab 90.00b-d 2527.55b-d 2168.10bc 22.83a-c 23.23a-c n150p33 92.5ab 90.67a-c 2636.58bc 2321.27b 23.19ab 23.38ab n150p55 91.27ab 94.8ab 3125.57a 2739.25a 22.96ab 23.56a-c cv (%) 2.21 2.73 5.12 5.28 1.59 2.92 cv = co efficient of variation. in a column, figures having common letter (s) do not differ significantly at 1% level by dmrt protein content of seed significantly higher protein content of seed was gained by applying 200 kg n which was statistical similar to 150 kg ha-1 n. these results are in agreement with (singh et al., 2001) in soybean. however, when the plants grown without added n and p fertilizer produced the lowest protein content in seeds. protein content significantly increased with increasing p fertilization 6.90 and 3.74 % higher protein content was recorded with 44 kg p compared to 22 and 33 kg pha-1, respectively. this might also be due to enhanced rate of bacterial nodulation (ssali and keya, 1986) and nitrogen fixation. conclusion two years result revealed that the application of n and p fertilizer up to150 and 44 kg ha1 exerted significantly positive effects on french bean in terms of seed yield and quality in joydebpur area. references 7 influence of nitrogen and phosphorus on yield and seed quality of french bean ali, m and s. lal. 1992 technology for rajmash cultivation in plain. indian farming 42:2526 ista. 1996. international rules for seed testing. seed sci. and technol. 24 (supppl.) 335 337 pp. kaisar, m. o., s. zaman, a. k. m. s. hoque, s. m. l. rahman and m. m. zaman. 2007. effect of nitrogen and phosphorus on growth, yield and profitability of french bean. bangadesh j. prod. sci. technol. 5(2): 373-376. kushwaha, b. l. 1994. response of french bean (phaseolus vulgaris l.) to nitrogen application in north indian plains. indian j. agron. 39: 34-37. mullins, g. l., b. f. hajek and c.w. wood. 1996. phosphorus in agriculture. bull. no.2. dept. of agronomy and soils, auburn, usa. padrit, j., j. g. hampton., m. j. hill and b. r. watkin. 1996. the effect of nitrogen and phosphorus supply to the mother plant on seed vigour in garden pea (pisum sativum l.) cv. pania. j. appl. seed prod. 14: 41-45. pierce,l. c. 1987. legumes in: vegetable: characters, production and marketing. john wiley and sons, new york. pp 561-567. prajapati, m. p. and b. m. patel. 2003. effects of integrated weed management and nitrogen levels of weed and productivity of french bean under north gujarat conditions. legume res. 26(2) 79-84. rao, b. r., s. p. singh and e.v.s. rao. 1983. nitrogen, potassium and phosphorus studies in pyrethrum (chrysanthemum cinerariifolium l.). j. agric. sci., 100: 509-511. rashid, m. m. 1999. sabji biggan. in bangla. 2nd ed., rashid publishing house, dhaka. pp. 396 -399. reddy, m., malla. padmaja, b. reddy and r. ram. 2010. response of french bean to irrigation schedules and nitrogen levels in talangana region of andhra pradesh. j. food legumes. 23(1): 38-40. saha, r. r. 2003. physiological aspects of yield and seed quality of mungbean (vigna radiata (l) wilczek ph.d. thesis, department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur. singh, r.v. 2000. response of french bean (phaseolus vulgaries l.) to plant, spacing and nitrogen, phosphorus fertilization. indian j. hort. 57: 338-341. srinivas, k. and l. b. naik 1990. growth, yield and nitrogen uptake in vegetable french bean (phaseolus vulgaris l.) as influenced by nitrogen and phosphorus fertilization. haryana j. hort. sci. 19 (1-2): 160-167. ssali, h. and s. o. keya. 1986. the effect of phosphorus and nitrogen fertilizer level on nodulation, growth and dinitrogen fixation of three bean cultivars. trop. agric. 63:105-109. tanaka, a., j. yamaguchi, s. miura and h. tamaru.1984. comparison of fertilizer nitrogen efficiency among field crops. soil sci. plant nutr. 30 (2): 199-208. veeresh, n. k. 2003. response of french bean (phaseolus vulgaris l.) to fertilizer levels in northern transitional zone of karnataka. m.sc. (agri.) thesis, university of agricultural science, dharwad. 8 kakon et al. vinod, r. p., s. acharya, s. ganesh, v. rajput, p . acharya and g. singh. 1999. effect of dates of sowing and graded doses of nitrogen on growth and yield of french bean cv. contender in eastern u. p. orissa j. hort. 27 (2): 39-42. wolfe, d. w., d.w. henderson, t. c. hsiao and a. alvino. 1988. interactive water and nitrogen effects of senescence of maize ii. photosynthesis and longevity of individual leaves. agron. j. 80: 865-870. bangladesh agron. j. 2014, 17(1): 81-88 effect of spacing on p and zn uptake of local t. aman rice varieties in khulna area s. parvin1, m. m. islam2, m. k. mondal3, k. g. quddus2 and a. m. mahmud4 1lecturer, agriculture studies, govt. bangabandhu college, rupsha, khulna 2professor, agrotechnology discipline, khulna university, khulna 3collaborative research scientist, irri, dhaka, bangladesh 4ngo focal person, dak diye jai corresponding author: parvin.shahanaz96@gmail.com key words: t. aman, spacing, phosphorus, zinc abstract a field experiment was conducted at the agronomy field of khulna university, khulna during t. aman season to evaluate the effects of spacing on nutrient content and total uptake of phosphorus and zinc by grain and straw of traditional rice of khulna region. the experiment was laid out in split-plot design with three replications assigning three varieties viz., jotai, bashfulbalam, ranisalute and three spacings viz., 30 cm x 30 cm, 40 cm x 40 cm and 50 cm x 50 cm. the variety was assigned in main plot and spacing in sub plot. the plot was fertilized with 40-50-35-5 kg of urea-tsp-mop and zns04 ha-1 respectively. the results indicated that the single effect of variety and spacing on p and zn content in grain and straw varied significantly while the straw p content was found insignificant. the interaction effect of variety and spacing on p and zn content was found significant in all the treatments. the highest p and zn content of grain was found from the variety ranisalute at 50 cm x 50 cm (v3s1) but in straw from ranisalute x 40 cm×40 cm (v3s2) and bashfulbalam x 30 cm × 30cm (v2s1), respectively. the total uptake of p and zn was found the highest from jotai variety at 30 cm x 30 cm spacing. from the interaction it showed that the highest p and zn uptake was found from jotai x 30 cm × 30 cm (v1s1) and the lowest from ranisalute x 50 cm x 50 cm (v3s3). the study indicated that though wider spacings of 40 cm x 40 cm and 50 cm x 50 cm increased the number of tillers hill-1 and nutrient uptake but it cannot increase the nutrient uptake and grain yield ha-1. so, 30 cm x 30 cm spacing showed positive relationship on nutrient uptake than 40 cm x 40 cm and 50 cm x 50 cm spacing. introduction rice is the staple food of bangladesh. it contributes about 90% of food grains and covers about 80% of total cropped area of the country. it provides about 70% of the calories consumed by 160 million people of bangladesh (ais, 2008). in order to increase the yield of rice plants the availability and uptake of proper and judicious use of fertilizers containing major and micronutrient is very important. the practice of intensive cropping with modern varieties causes a marked depletion of inherent nutrient reserve in soils of bangladesh. consequently in addition to n, p and k deficiencies, some other nutrient such as zn, s and b deficiencies are being observed in many parts of the country (haque and jahiruddin, 1994). fertilizer is the most important input for rice production. for the best yield of rice plant along with nitrogen requirements, phosphorus and zinc is also needed. the application of p and zn can play important role in grain setting, increased grain yield and nutrient concentration of rice. phosphorus is important for the growth, reproduction, yield and quality of rice crop. tillering of rice plant is positively co-related with phosphorus. it also promotes root development and elongation capability of rice plant (hossain et al., 2009). zinc deficiency has been detected as the third major nutritional problem for bangladesh soil next to n and p limiting the growth of wetland rice. in some places of bangladesh yield loss due to zn deficiency 82 parvin et al. ranged from 10-18%. zinc plays an important role in many physiological functions of plants. planting densities exceed an optimum level competition among plants for macro and micro nutrients becomes severe consequently the plant growth stunted and grain yield decreases. the number of tillers per square meter is increased with the improvement of rice production (islam, 2001). however, scanty information is available about the effect of spacing on the uptake of nutrients particularly p and zn on rice. therefore, the present study was conducted to find out the effect of spacing on the uptake and content of p and zn of local t. aman rice varieties of khulna area. materials and methods the experiment was conducted in the field of agro technology discipline at khulna university during t. aman season. the soil was characterized by medium textured silty loam having ph value 7.5 and organic matter 3.80%. before raising seeds in the nursery, seeds were water soaked for 24 hours and these were kept in jute bags in dark conditions. after sprouting, the seeds were sown in wet seed bed. thirty days old seedlings were uprooted carefully from the nursery and transplanted as single seedling hill-1 on the well puddled experimental plots. three popular t. aman rice varieties viz, jotai (v1), bashfulbalam (v2) and ranisalute (v3) were selected for the study. the varieties were planted in three different spacings viz, 30 cm x 30 cm (s1), 40 cm x 40 cm (s2), and 50 cm x 50 cm (s3). the variety was assigned in main plot and spacing in sub plot. the plot size was 4.0 m x 2.5 m. the land was fertilized with 40-50-35-5 kg of ureatsp-mop-znso4 ha-1 respectively. the full dose of fertilizers and half of urea was applied as basal dose during final land preparation and the remaining half of urea was applied in two splits at active tillering and during panicle initiation stage. grain yield and straw yield were recorded from whole plot basis leaving boarder lines. grain yield was adjusted at 14% moisture content. in order to conduct chemical analysis during harvest five representative samples of grain and straw from each sub plot were collected. the collected samples were analysed and phosphorus (p) was determined by spectrophotometer and zinc (zn) by atomic absorption spectrophotometer. the data was analyzed following standard statistical procedures (gomez and gomez, 1984) using a computer operated program mstatc. results and discussion p concentration phosphorus content in grain differed significantly due to the main effect of variety and spacing but it was found insignificant in straw (table 1). it was ranged from 0.102% to 0.116% in grain and 0.030% to 0.032% in straw from the effect of varieties and 0.107% to 0.113% in grain and 0.028% to 0.032% in spacings. among three varieties the maximum p content of grain (0.116%) was found from ranisalute variety which was followed by bashfulbalm (0.115%) and jotai (0.102%). the content of p was found samilar (0.113%) in 50 cm x 50 cm and 30 cm x 30 cm spacing which was followed by 40 cm x 40 cm spacing in straw (0.107%). the grain content of p was higher compared to straw content of that in all treatments which supports the findings of yoshida (1981) that contents of phosphorus (p) is generally higher in the panicles than in the straw (leaves and culm). table 1. effect of variety and spacing on p and zn content of grain and straw treatments p (%) zn (ppm) grain straw grain straw v1 (jotai) v2 (bashfulbalam) v3 (ranisalute) 0.102 0.115 0.116 0.032 0.031 0.030 26.17 36.94 37.61 37.33 40.17 34.28 83 spacing effect on p and zn content of local t. aman rice varieties level of significance 0.01 ns 0.01 0.01 lsd(0.01) 0.06899 1.220 2.821 s1 (30 cm x 30 cm) s2 (40 cm x 40 cm) s3 (50 cm x 50 cm) 0.113 0.107 0.113 0.032 0.032 0.028 32.11 32.72 35.89 39.50 37.44 34.83 level of significance 0.05 ns 0.01 0.01 lsd(0.01) 0.06899 1.220 2.821 cv (%) 7.00 24.51 1.67 3.47 interaction effect of variety x spacing was found statistically significant in both grain and straw (table 2). it was ranged from 0.095% to 0.0128% in grain and 0.025% to 0.037% in straw. the highest grain content (0.128%) was found from v3s3 and the lowest (0.095%) from jotai x 30 cm x 30 cm (v1s1). in straw the highest p content (0.037%) was found from ranisalute x 40 cm x 40 cm (v3s2) and the lowest (0.025%) from both ranisalute x 50 cm x 50 cm (v3s3) and bashfulbalam x 40 cm x 40 cm (v2s2). zn concentration zn concentration in grain and straw was significantly affected by the main effect of variety and spacing. among three varieties the grain zn content was found the maximum (37.61 ppm) from jotai which was followed by bashfulbalam (36.94 ppm) and ranisalute (26.17 ppm). but in straw zn content was found the highest (40.17 ppm) from bashfulbalam and the lowest (34.28 ppm) from ranisalute. the highest zn content (35.89 ppm) was found from 50 cm x 50 cm and the lowest (26.17 ppm) from 30 cm x 30 cm spacing. in straw the highest zn content (37.44 ppm) was found from 40 cm x 40 cm and the lowest (34.83 ppm) from 50 cm x 50 cm spacing (table 2). interaction effect of variety x spacing was found statistically significant in both grain and straw zn content ranged from 24.67 ppm to 41.00 ppm in grain and 32.00 ppm to 43.33 ppm in straw (table 2). the highest (41.00 ppm) and the lowest (24.67 ppm) zn content in grain was obtained from ranisalute x 50 cm x 50 cm (v3s3) and jotai x 30cm x 30cm (v1s1), respectively. the straw content of zn was higher compared to grain content that confirms the findings of yoshida (1981). the highest (43.33 ppm) and the lowest (32.00 ppm) straw zn content was obtained from bashfulbalam x 30 cm x 30 cm (v2s1) and ranisalute x 50 cm x 50 cm (v3s3), respectively. phosphorus uptake the interaction effect of variety x spacing on p uptake was shown in figure 1, 3 and 5. it was observed that variety jotai uptake the highest p than bashfulbalam and ranisalute (fig. 1, 3 and 5). the spacing 30 cm x 30 cm uptake the highest p than 40 cm x 40 cm and 50 cm x 50 cm. though wider spacing enhanced nutrient uptake but the highest grain yield was obtained from 30 cm x 30 cm spacing as a result the total uptake of p was obtained from 30 cm x 30 cm spacing. actually wider spacing promoted more tillering than lower spacing but tiller number per square meter is important for total uptake of nutrient than tillers hill-1 (islam, 2001). the interaction of jotai x 30 cm x 30 cm (v1s1) uptake the highest p (4.85 kg ha-1) and the lowest (3.0 kg ha-1) was found from ranisalute x 50 cm x 50 cm (v3s3) interactions. table 2. effect of variety x spacing interaction on p and zn content of grain and straw interaction (variety x spacing) p (%) zn (ppm) grain straw grain straw v1s1 0.108 0.32 24.67 42.17 v1s2 0.102 0.35 26.83 35.17 v1s3 0.950 0.28 27.00 34.67 v2s1 0.115 0.35 36.83 43.33 v2s2 0.115 0.25 34.33 39.33 v2s3 0.115 0.32 39.67 37.83 v3s1 0.115 0.28 34.83 33.00 84 parvin et al. v3s2 0.103 0.37 37.00 37.83 v3s3 0.128 0.25 41.00 32.00 lsd(0.01) 0.07 ns 1.22 2.82 cv (%) 7.00 24.51 1.67 3.47 v1 = jotai, v2=bashfulbalam, v3=ranisalute s1 = 30cm x 30cm, s2=40cm x 40cm, s3=50cm x 50cm zinc uptake the interaction effect of variety x spacing on zn uptake was shown in figure 2, 4 and 6. it was observed that variety jotai uptake the highest zn than bashfulbalam and ranisalute (fig. 2, 4 and 6). the spacing 30 cm x 30 cm uptake the highest zn than 40 cm x 40 cm and 50 cm x 50 cm. though wider spacing enhanced nutrient uptake but the highest yield was obtained from 30 cm x 30 cm spacing. the interaction of jotai x 30 cm x 30 cm (v1s1) uptake the highest zn (0.273 kg ha-1) and the lowest (0.156 kg ha-1) was found from ranisalute x 50 cm x 50 cm (v3s3). fig. 1. phosphorus uptake by jotai variety in three spacings fig. 2. zinc uptake by jotai variety in three spacings 85 spacing effect on p and zn content of local t. aman rice varieties fig. 3. phosphorus uptake by bashfulbalam variety in three spacing fig. 4. zinc uptake by bashfulbalam variety in three spacing fig. 5. phosphorus uptake by ranisalute variety in three spacing 86 parvin et al. fig. 6. zinc uptake by ranisalute variety in three spacing nutrient status of soil nutrient status of the experimental soil before planting and after harvest was shown in table 3. before planting the nutrient n, p, k, zn and s content of soil was 0.207%, 7.15 ppm, 0.36 meq. 100 g-1 soil, 0.46 ppm and 129.53 ppm, respectively. after harvest the n, p, k, zn and s content of soil were 0.250%, 4.17 ppm, 0.27 m.eq/100 g soil, 0.883 ppm and 218.38 ppm, respectively. recovery of p and zn was obtained from basal application of 50 kg p2o5 ha-1 and 30 kg znso4 ha-1. in the experimental plot the deficiency of p and zn was present before planting and different level of p and zn fertilizer was not applied in the treatment that’s why apparent recovery of these two nutrients was smaller than field experiments. the results indicated that added elements (p and zn) might have residual effect on the succeeding crop (jahiruddin et al., 1994). table 3. some important properties of the experimental soils parameters before planting after harvest texture silty loam silty loam ph 7.5 7.6 e.c 7.77 ds m-1 8.87ds m-1 organic matter 3.80% 5.17% total n 0.207% 0.25% exchangeable k 0.36 meq. 100 g-1 soil 0.27 meq. 100 g-1 soil exchangeable ca 27.50 meq. 100 g-1 soil 38.17 meq. 100 g-1 soil exchangeable mg 5.75 meq. 100 g-1 soil 7.78 meq. 100 g-1 soil available p 7.15 ppm 4.17 ppm total zn 0.46 ppm 0.883 ppm available s 129.53 ppm 218.38 ppm conclusion 87 spacing effect on p and zn content of local t. aman rice varieties the overall results of the present study showed that the single and interaction effect of variety and spacing showed significant influence on phosphorus and zinc content in grain and straw but the straw phosphorus content was insignificant from the single effect of variety and spacing. the uptake of phosphorus and zinc was found the highest in closer spacing than wider spacing. the number of tillers square meter-1 was more in closer spacing 30 cm x 30 cm than wider spacing 40 cm x 40 cm and 50 cm x 50 cm. so, it can be the concluded that the uptake of nutrient depends on number of tillers square meter-1 than number of tillers hill-1. references ais (agricultural information service). 2008. krishi dairy. agric. int. ser. dhaka. pp.20-22. brri (bangladesh rice research institute). 1989. annual internal review for 1989. bangladesh rice res. inst. gazipur-1701. pp.169-171. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. intl. rice res. inst. los banos, laguna, philippines. pp.97-116. haque, m. s. and m. jahirruddin. 1994. effect of single and multiple application of sulphur and zinc in a continuous rice cropping pattern. indian j. agric. res. 28(1): 9-14. hossain, m. b., m. jahiruddin, m. r. h. loppert, g. m. panaullah, m. r. islam and j. m. duxbury. 2009. the effects of iron plaque and phosphorus on yield and arsenic accumulation in rice. j. plant soil. 317: 167-176. islam, m. 2001. enhancement of and yield of boro rice through modification of sri (system of rice intensification) technique in terms of fertilizer management, spacing and seedling age. m. sc. thesis, dept. of agronomy. bau, mymensingh. jahiruddin, m., m. n. islam, m. a. hashem and m. r. islam. 1994. influence of sulphur, zinc and boron on yield and nutrient uptake of br2 rice. progress. agric. 59(1): 61-67. rahman, k. m. m., m. a. k. chowdhury, f. sharmeen, a. sarkar, m. a. hye and g. c. biswas. 2011. effect of zinc and phosphorus on yield of oryza sativa (cv.br-11). bangladesh res. pub. j. 4 (5): 351-358. yoshida, s. 1981. fundamentals of rice crop science. the intl. rice res. inst. los banos, laguna, philippines. bangladesh agron. j. 2014, 17(1): 73-80 allelopathic effect of brassica on weed control and yield of wheat p. k. biswas, m. m. morshed, m. j. ullah and i. j. irin dept. of agronomy, sher-e-bangla agricultural university, dhaka corresponding author: parimalbiswas@hotmail.com key words: allelopathy, weed control, rapeseed/mustard, wheat abstract the experiment was conducted at the agronomy farm of sher-e-bangla agricultural university to identify the allelopathic effect of brassica species along with their incorporation methods to control weeds in wheat field. the experiment was assigned in a split-plot design where three cultivated brassica spp. were in the main plot and five different ways of green brassica biomass inclusion were in the sub-plot. brassica crops were uprooted at 30 days after sowing (das) and incorporated to the soil @ 0.5 kg m-2 as per treatment. wheat seeds were sown on december 04, 2007 using 20 cm line to line distance. weeds e.g., amaranthus spinosus, a. viridis, lindernia procumbens, heliotropium indicum, polygonum hydropiper, celosis argentina, ageratum conyzoides, brassica kaber and digitaria ischaemum were not found in the wheat field. significantly the highest weed dry matter (1.72 g m-2) was found in brassica juncea plots at 30 das but in brassica napus field (1.44 g m-2) at 50 das. the lowest weed dry matter at 30 das (0.89 g m-2) was recorded with total incorporation of brassica biomass to the soil but 50% incorporation and 50% spreading at 50 das. the brassica biomass spreading above ground, mixed with soil and 50% spreading + 50% mixed with soil resulted positively compared to other ways of biomass incorporation. the highest grain yield (3.83 t ha-1) of wheat was given by brassica juncea when spreaded on the above ground soil. introduction wheat (triticum aestivum l.) is the most important cereal crop in the world as well as in bangladesh that provides about 20% of total food calories. weed is the natural enemy of wheat that reduces its yield if not properly controlled. the yield reduction of wheat by weed is reported to be 20 30% (turk and tawaha, 2002) and 150% by peterson (1965). some crops are specially useful because they have the ability to suppress other plants that attempt to grow around to them. allelopathy refers to a plant's ability to chemically inhibit the growth of other plants. rapeseed and mustard are reported the most useful allelopathic cover crop that reduced total weed biomass in soybean by 40 49% (krishnan et al., 1998). weed suppression is effective when crop residues left undisturbed on the soil surface but the effect is lost when tilled into the soil (sheila, 1986). putnam et al. (1983) reported that weeds that were reduced by rye mulch included ragweed (43%), pigweed (95%) and common purslane (100%). worsham (1991) and schilling et al. (1986) reported 68-80% reduction of broadleaf weeds by rye. yenish and worsham (1993) also reported highest weed control by rye application. anon. (1993) reported allelopathic effect of rapeseed and showed 90% reduction of yellow nutsedge on sweet potatoes. boydston and hang (1995) reported that all members of the mustard family (brassicaceae) contain mustard oils that inhibit plant growth and seed germination. the concentration of allelopathic mustard oils varies with species and variety of mustard. sullivan (2003) reported that crop residues when left on the soil surface, can be expected to reduce weed emergence by 75 to 90% and when decomposed, weed suppression effect also declined. an attempt was therefore, undertaken to study the allelopathic effect of rapeseed and mustard in controlling weeds in wheat. mailto:parimalbiswas@hotmail.com 74 biswas et al. materials and methods the experiment was conducted at the agronomy farm of sher-e-bangla agricultural university, dhaka 1207, during the period from november 2007 to march 2008 in a silty clay loam soil having low organic matter (0.82%) and slightly acidic soil (ph 5.47-5.63). three brassica varieties one from campestris (bari sarisha-15), one from juncea (bari sarisha-11) and the other from napus (bari sarisha-13) species were sown on november 02, 2007. the crop was fertilized with 180-100-180-60-10-5 kgha-1 of urea, tsp, mop, gypsum, boric acid and zinc oxide, respectively of which half of urea and the full amount of other fertilizers applied as basal dose. as the crops were uprooted, no additional urea fertilizer was applied. weeding, mulching and thinning were done at 20 das (days after seeding). the brassica crop was uprooted at 30 das and the land was then ploughed and cross ploughed, leveled and fertilized as per recommendation of wheat. the experiment was laid out in split-plot design with three replications. three brassica species was assigned in the main plot and six different ways of biomass incorporation (no biomass application, biomass spreading above the ground, biomass mixed with soil, biomass spreading in lines and 50% biomass as spreading + 50% biomass as mixed with soil) in the sub plot. the wheat variety shatabdi (bari gom21) was sown on 04 december, 2007 maintaining 20 cm line distance. one third urea and the full amount of other fertilizers were applied as basal and the rest urea in two equal splits at cri stage and before flowering stage. all the intercultural operations were done as and when necessary. weed data was recorded on 30 and 50 das. the yield and other data were recorded using standard procedure. the collected data were analyzed and the mean differences evaluated by least significant difference test (lsd). results and discussion weed species twelve weed species belongs to 7 families were found infested in the experimental field of which cyperous rotundus, cynodon dactylon, eleusine indica, digitaria sanguinalis, chenopodium album were found with major population whereas 9 weeds had been found unavailable in wheat field but available to the surrounding areas. the name and family of the weeds are shown in table 1. the results showed that brassica biomass had allelopathic effect to suppress some weed species in wheat field. anon. (1993) also reported the suppressive nature of rapeseed to control weeds in sweet potatoes. weed density and weight inclusion of different brassica biomass had no significant variations on weed population in wheat field at 30 and 50 das but the methods of biomass incorporation resulted significant differences of weed population at 30 das though no variation was observed at 50 das (table 2). the lowest number of weed population (15.33 m-2) was found in b4 (spreading in lines) that was similar to b2 (spreading above ground) and b5 (50% spreading + 50% mixed with soil). sullivan (2003) reported the highest suppressive effect of crop residues when left on the surface than decomposed to the soil. uremis et al. (2009) reported the allelopathic potential of residues of some brassica species suppressed johnsongrass. the result was also in agreement with the findings of boydston (2008) who reported that brassicaceae cover crops suppress weeds due to allelopathic substances released during degradation of the cover crop residues. table 1. local name, common name, scientific name, and family of weeds unavailable in brassica biomass treated plots local name common name scientific name family weeds available in the experimental plot mutha nut sedge cyperus rotundus cyperaceae chapra goose grass eleusine indica gramineae 75 allelopathic effect of brassica on wheat local name common name scientific name family durba bermuda grass cynodon dactylon gramineae anguli ghas scrab grass digitaria sanguinalis gramineae bon mosur wild lentil vicia stiva leguminosae choto shama jungle rice echinochloa colonum gramineae bathua lambsquarter chenopodium album chenopodiaceae tita begun tita begun solanum torvum solanaceae chatidhara flat cyperus cyperus compresus cyperaceae shetodron leucas leucas aspera labiatae malancha alligator weed alternanthera philoxeroides amaranthaceae bon china torpado grass panicum repens gramineae weeds unavailable in the experimental plot but available to the adjacent area khet papri khet papri lindernia procumbens scrophulariaceae hati shur wild heliotrop heliotropium indicum boraginaceae kata notae spiny pig weed amaranthus spinosus amaranthaceae shak notae pig weed amaranthus viridis amaranthaceae bish katali smart weed polygonum hydropiper polygonaceae shet morog white cock’s comb celosia argentina amaranthaceae chagla gacha goat weed ageratum conyzoides compositae bon sarisha wild mustard brassica kaber cruciferae choto anguli smooth scrab grass digitaria ishchamaemum gramineae the highest weed dry weight (1.72 g m-2) was recorded in juncea plots as compared to brassica campestris (1.16 g m-2) and brassica napus (1.16 g m-2) at 30 das but at 50 das brassica napus treated plots showed the highest weed dry weight (1.44 g m-2) and the brassica juncea showed the lowest weed dry weight (0.96 g m-2) that was similar to brassica campestris (1.08 g m-2) treated plots (table 2). the different ways of biomass incorporation showed significant variations in weed dry weight at 30 das and 50 das and for both the situation the control (no brassica biomass incorporation) plots had the highest weed dry weight and b2 at 30 das and b5 at 50 das showed the lowest weed dry weight (table 2). cheema et al. (2008) reported that inclusion of allelopathic crops in rotation systems for weed suppression by early post-emergence application of the mixture of sorghum, sunflower, brassica or mulberry water extracts suppressed total weed dry weight. the interaction of brassica species and ways of biomass incorporation showed significant variations of weed population in wheat field at 30 das and at 50 das (table 3). the highest weed population (37.33 m-2) was recorded in s2b1 plots at 30 das. the lowest weed population (13.67 m-2) was observed in s3b4 at 30 das and in s1b3 (8.67 m-2) at 50 das. the lowest weed dry weight (0.74 g m-2) was found in s3b2 at 30 das and in s1b5 (0.51 g m-2) at 50 das. table 2. weed density and weight of wheat as affected by brassica biomass and methods of incorporation treatments weed density (no. m-2) weed dry weight (g m-2) 30 das 50 das 30 das 50 das brassica species: s1 s2 s3 lsd(0.05) incorporation methods: 17.67 25.60 22.47 ns 14.07 20.20 18.80 ns 1.16 1.72 1.16 0.350 1.08 0.96 1.44 0.208 76 biswas et al. b1 b2 b3 b4 b5 lsd(0.05) 26.78 17.78 26.89 15.33 22.78 9.390 17.78 20.11 20.89 16.56 13.11 ns 1.49 0.89 1.59 1.11 1.65 0.534 1.66 1.10 1.31 0.93 0.80 0.491 s1 = b. campestris s2 = b. juncea s3 = b. napus; b1 = no biomass b2 = spreading above ground b3 = mixed with soil b4 = spreading in lines b5 = 50% spreading + 50% mixed with soil table 3. weed density and weight in wheat as affected by interaction of brassica biomass and methods of incorporation treatments weed density (no. m-2) weed dry weight (g m-2) 30 das 50 das 30 das 50 das s1 b1 s1 b2 s1 b3 s1 b4 s1 b5 s2 b1 s2 b2 s2 b3 s2 b4 s2 b5 s3 b1 s3 b2 s3 b3 s3 b4 s3 b5 lsd(0.05) 17.00 15.67 15.33 17.67 22.67 37.33 21.33 36.67 14.67 18.00 26.00 16.33 28.67 13.67 27.67 16.325 19.33 17.67 8.67 15.67 9.00 22.00 29.67 14.00 19.00 16.33 12.00 13.00 40.00 15.00 14.00 22.252 0.91 1.01 0.93 1.13 1.80 2.31 0.92 2.68 1.26 1.44 1.26 0.74 1.16 0.93 1.72 0.925 1.78 1.31 1.01 0.78 0.51 1.71 1.03 0.47 0.99 0.61 1.48 0.95 2.46 1.04 1.29 0.845 s1 = b. campestris s2 = b. juncea s3 = b. napus; b1 = no biomass b2 = spreading above ground b3 = mixed with soil b4 = spreading in lines b5 = 50% spreading + 50% mixed with soil wheat yield and other crop characters incorporation of brassica juncea biomass to the wheat field showed the maximum 1000-grain weight of wheat (42.13 g) that statistically similar to brassica napus but the lowest grain weight in brassica campestris biomass incorporation. mansoor et al. (2004) stated that water extracts of sorghum, eucalyptus and acacia were significantly affected 1000-grain weight of mungbean. the highest harvest index (48.47%) was given by brassica campestris biomass incorporation that similar to brassica juncea and the lowest in brassica napus (table 4). table 4. effect of brassica spp. and ways of biomass incorporation on yield and other crop characters of wheat treatments plant height (cm) filled grains spike-1 (no.) 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) 77 allelopathic effect of brassica on wheat brassica species: s1 s2 s3 lsd(0.05) incorporation methods: b1 b2 b3 b4 b5 lsd(0.05) 84.15 82.53 84.19 ns 81.74 86.08 84.83 79.96 85.50 2.340 41.32 39.63 45.12 ns 38.95 43.08 44.32 40.62 43.16 3.491 37.07 42.13 40.38 2.883 39.56 40.84 43.63 37.18 38.30 3.790 3.43 3.52 3.32 ns 3.54 3.46 3.32 3.37 3.43 ns 3.64 3.84 3.73 ns 3.85 3.76 3.84 3.66 3.56 ns 48.47 47.60 47.27 1.012 47.78 48.11 46.22 47.78 49.00 0.972 s1 = b. campestris s2 = b. juncea s3 = b. napus; b1 = no biomass b2 = spreading above ground b3 = mixed with soil b4 = spreading in lines b5 = 50% spreading + 50% mixed with soil the tallest plant (86.08 cm) was recorded from b2 (spreading above ground) that similar to b5 and b3 but b4 produced the shortest plant height (79.96 cm). the maximum number of filled grains spike-1 (44.32) was recorded from b3 (mixed with soil) that similar to b5 (50% spreading + 50% mixed with soil), b2 (spreading above the ground) and b4 (spreading in line) while the minimum (38.95) was found in b1 (control) plot (table 4). b3 treatment showed the highest 1000-grain weight (43.63 g) that similar to b2 whereas b4 gave the lowest grain weight (37.18 g) that similar to b5, b2 and b1. the highest harvest index (49.00%) was recorded from b5 that similar to b2, b1 and b4 while the lowest (46.22%) in b3. the combined effect of brassica species and different incorporation methods significantly effect the grain yield and other studied crop characters of wheat where s2b2 (brassica juncea spreading above ground) showed the highest grain yield (3.83 t ha-1), straw yield (4.17 t ha-1), superior plant height (85.90 cm) and 1000-grain weight (43.93 g) whereas the lowest grain yield (3.06 t ha-1) was found in s3b2 (brassica napus spreading above ground). baker and bhowmik (2001) reported that application of imported residues was found more effective in yield enhancement of vegetable cropping systems. the s3b5 (brassica napus with 50% spreading + 50% mixed with soil) had the maximum number of filled grains spike-1 (47.24) and the minimum (35.87) in s1b4 (table 5). table 5. interaction effect of brassica spp. and ways of biomass incorporation on yield and other crop characters of wheat treatments plant height (cm) filled grains spike-1 (no.) 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) 78 biswas et al. s1 b1 s1 b2 s1 b3 s1 b4 s1 b5 s2 b1 s2 b2 s2 b3 s2 b4 s2 b5 s3 b1 s3 b2 s3 b3 s3 b4 s3 b5 lsd(0.05) 83.20 83.00 88.00 81.13 85.40 79.80 85.90 84.67 79.60 83.07 82.63 89.33 81.83 79.13 88.03 4.156 38.91 44.67 46.40 35.87 40.73 36.07 37.51 43.15 39.76 40.88 41.24 46.19 42.58 46.03 46.69 6.047 38.65 34.97 39.81 33.09 38.49 40.72 43.93 48.77 39.40 37.11 38.67 42.35 42.02 38.52 38.43 6.564 3.61 3.50 3.39 3.39 3.28 3.33 3.83 3.33 3.34 3.75 3.67 3.06 3.23 3.38 3.28 0.612 3.44 3.72 3.95 3.64 3.44 3.83 4.17 3.89 3.69 3.61 4.27 3.40 3.70 3.66 3.61 0.733 51.00 48.67 46.00 48.00 48.67 46.33 47.67 46.00 47.33 51.67 46.00 48.00 46.67 48.00 47.67 1.684 s1 = b. campestris s2 = b. juncea s3 = b. napus; b1 = no biomass b2 = spreading above ground b3 = mixed with soil b4 = spreading in lines b5 = 50% spreading + 50% mixed with soil conclusion irrespective of three studied species, brassica crop has significant role to suppress weed in wheat field. the nature of weed suppression varied among the incorporation methods. the higher grain yield of wheat was found with the incorporation of brassica juncea biomass as spreading above ground. it is necessary to isolate the allelochemical in brassica for implementing such eco-friendly method of weed control. acknowledgement the financial support of saures (sher-e-bangla agricultural university research system) to conduct the research is gratefully acknowledged. references anonymous. 1993. sweet potato plants vs. weeds. hortideas. january. p.8. baker, a. v. and p. c. bhowmik. 2001. weed control with crop residues in vegetable cropping systems. j. crop prod. 4: 163-183. boydston, r. 2008. the use of mustard cover crops in potato rotations. 5th world congress on allelopathy. the saratoga hilton, saratoga springs, new york, usa from 21-25 september, 2008. p.58. boydston, r. and a. hang. 1995. rapeseed green manure crop suppresses weeds in potato. weed technol. 9: 669-675. cheema, z. a., a. khaliq and m. n. mushtaq. 2008. current allelopathic research in pakistan-some implications. 5th world congress on allelopathy. the saratoga hilton, saratoga springs, new york, usa from 21-25 september, 2008. p.83. krishnan, g., d. l. holshouser and s. j. nissen. 1998. weed control in soybean (glycine max) with green manure crops. weed technol. 12: 97-102. mansoor, m., h. k. ahmad, h. khan and m. yaqoob. 2004. development of economical weed management strategies for mungbean (vigna radiata l. wilczek.). pak. j. weed sci. res. 10: 151-156. 79 allelopathic effect of brassica on wheat peterson, r. f. 1965. wheat. interscience publishers, inc. new york. p.256. putnam, a. r., j. defrank and j. p. barnes. 1983. exploitation of allelopathy for weed control in annual and perennial cropping systems. j. chem. ecol. 9: 1001-1010. schilling, d. g., a. d. worsham and d. a. danehower. 1986. influence of mulch, tillage, and diphenamid on weed control, yield, and quality in no-till flue-cured tobacco. weed sci. 34: 738-744. sheila, d. 1986. update: suppressing weeds with allelopathic mulches. the ipm practitioner. april. pp.1-4. sullivan, p. 2003. principles of sustainable weed management for croplands. attra publication #ip039. turk, m. a. and a. r. m. tawaha. 2002. effect of sowing rates and weed control methods on winter wheat under mediterranean environment. pakistan j. agron. 16: 461-464. uremis, i., m. arslan, a. uludag and m. k. sangun. 2009. allelopathic potentials of residues of 6 brassica species on johnsongrass (sorghum halepense l. pers.). african biotech. 8: 3497-3501. worsham, a. d. 1991. allelopathic cover crops to reduce herbicide input. proceedings of the southern weed science society. 44th annual. volume 44. pp.58-69. yenish, j. p. and a. d. worsham. 1993. replacing herbicides with herbage: potential use for cover crops in notillage. pp.37-42. in: p.k. bollich, (ed.) proceedings of the southern conservation tillage conference for sustainable agriculture. monroe, la. june 15-17. 80 biswas et al. bangladesh agron. j. 2015, 18(2): 71-78 physiological basis of water stress tolerance in soybean k. k. sarkar1, m. a. mannan1*, m. m. haque1 and j. u. ahmed2 1department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh. 3department of crop botany, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 *corresponding author: mannanbsmrau@yahoo.com key words: physiology, water stress, tolerance, soybean abstract an experiment was conducted to study the effects of water stress on physiological parameters associated to drought tolerance in soybean at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh during january to april, 2015. four soybean genotypes namely i) bu soybean 1 ii) binasoybean 1 iii) galarsum and iv) bari soybean 5 were grown in two watering regimes viz. control (80% of the field capacity) and water stress (50% of the field capacity). genotypic variability was found in water stress tolerance in soybean. highest accumulation of leaf proline, sugar and water content and lower accumulation of malondialdehyde were found in binasoybean 1 compared to other genotypes. lowest yield reduction was found in binasoybean 1. binasoybean 1 showed relatively higher drought tolerance whereas bari soybean 5 was found susceptible to yield. it was found that higher water stress tolerance in binasoybean 1 was associated with better water relations and higher accumulation of sugar and proline and lower accumulation of malondialdehyde content in leaf. introduction water deficit is the most severe abiotic stress limiting plant growth and crop production (moussa, 2011; rohbakhsh, 2013). with the change in global climate, the soil moisture balance and available moisture in soil is going to change and the frequency of regional drought will increase (fuhrer, 2003). water deficit induces several morphological, physiological, biochemical and molecular responses in several crop plants, which would help them to adapt to such limiting environmental conditions (arora et al., 2002). mechanisms of drought tolerance, especially at low water stress, involve processes at the cellular level, the most important being osmotic adjustment and protection of the membrane system. in order to keep osmotic balance, specific types of organic molecules (such as soluble sugars, proline etc) are accumulated in the cytoplasm. those compounds protect plants against stresses by cellular adjustment through the protection of membranes integrity and enzymes stability (farooq et al., 2009). so, aim of the research work was to analyze the changes of physiological parameters those are associated with drought tolerance in soybean under water stress materials and methods the experiment was conducted at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh. four soybean genotypes namely i) bu soybean 1 ii) binasoybean 1 iii) galarsum and iv) bari soybean 5 were grown in plastic pots of diameter (24 cm) x height (30 cm) during january to april, 2015. the soil used in the pot was clay loam in texture and poor fertility status. the ph of the soil was 7.1, organic carbon 0.60%, total n 0.05%, available p 0.08 mg/100 g dry soil, exchangeable k 0.33 cmolc kg-1 dry soil and cec 14.58 cmolc kg-1 dry soil. compost (1/4 th of the soil volume) and 0.27-0.28-0.20 g of urea, triple super phosphate and muriate of potash per pot for supplying n, p2o5 and k2o, respectively were 72 sarkar et al. incorporated uniformly into the soil. the compost was from cow dung which contained 0.8% n, 0.6% p2o5 and 1.0% k2o on dry weight basis. ten bold seeds were sown in each plastic pot containing about 12 kg air dried soil. after seedling establishment, six uniform and healthy plants were allowed to grow in each pot. two watering regimes of the plants viz. control (80% of the field capacity) and water stress (50% of the field capacity) were maintained from at 1st trifoliate growth stage i. e., 14 days after sowing upto maturity. the experiment was designed at factorial completely randomized (crd) with three replications. relative water content, proline, total sugar and malondialdehyde (mda) content of leaf were recorded at 15, 30 and 45 days after water stress. the uppermost fully developed leaves were collected from each plant and the relative water content (rwc), proline, malondialdehyde (mda) and total sugar were measured according to schonfeld et al.(1988), bates et al. (1973), health & packer (1968) and somogyi (1952), respectively. normal management practices were applied for all treatments. at maturity two plants were collected from each pot. data on number of pod/plant, number of seed/pod, 100 seed weight and seed yield/plant were recorded. seed yield per plant was adjusted at 14% moisture content. the recorded data were statistically analyzed and the treatment means were compared by least significance difference (lsd) test (gomez & gomez, 1984) results and discussion relative water content the effect of water stress on relative water content (rwc) of the genotypes varied significantly at 15, 30, 45 days after drought imposition (table 1). the rwc both in control and water stress condition was recorded highest in binasoybean 1, while the lowest in bu soybean 1 at 15 days after drought imposition. relative (per cent of control) water content of the genotypes ranged from 93.01 to 95.25% at water stress. highest relative water content was obtained from binasoybean1 (95.25%), followed by galarsum (94.81%) and bu soybean 1 (94.05%) while lowest in bari soybean 5 (93.01%). the reduction of the rwc due to water stress was lower in binasoybean 1 (4.75%), while that was higher in bari soybean 5 (6.99%). at 30 days, the rwc both in control and water stress was recorded highest in binasoybean 1, while the lowest in bu soybean 1. relative (per cent of control) water content of the genotypes at different growth stages ranged from 85.36to 92.18% at water stress. highest relative water content was obtained from binasoybean 1 (92.18%), followed by galarsum (89.82%) and bu soybean 1 (86.19%) and lowest in bari soybean 5 (85.36%). the reduction of the rwc due to water stress was lower in binasoybean 1 (7.82%), while higher in bari soybean 5 (14.6%). at 45 days, the rwc both in control and water stress condition was recorded highest in galarsum and binasoybean 1, respectively, while the lowest in binasoybean 1 and bu soybean 1, respectively. relative water content of the genotypes ranged from 68.28 to 92.97% at water stress. highest relative water content was obtained from binasoybean 1 (92.97%), followed by galarsum (85.17%) and bu soybean 1 (69.11%) and lowest in bari soybean 5 (68.28%). the reduction of the rwc due to water stress was lower in binasoybean 1 (7.03%), while that was higher in bari soybean 5 (31.72%). the reduction in leaf water was provoked by the water deficiency in soil, in which the water stress simulated artificially in this experiment cause as direct consequence changes in leaf relative water content reported as verslues et al. (2006). velu and palanisami (2002) also reported that water stress significantly reduced relative water content of the plant. table 1.relative water content (rwc %) of soybean genotypes as affected by water stress at different days after water stress (daws) 15 daws 30 daws 45 dawsgenotypes control water stress control water stress control water stress bu soybean 1 87.37 82.17 (94.05) 78.05 67.27 (86.19) 81.31 56.19 (69.11) 73 physiological basis of water stress tolerance in soybean binasoybean 1 90.37 86.08 (95.25) 82.38 75.94 (92.18) 77.37 71.93 (92.97) galarsum 90.02 85.35 (94.81) 80.83 72.60 (89.82) 82.79 70.51 (85.17) bari soybean 5 88.88 82.67 (93.01) 79.90 68.20 (85.36) 82.64 56.43 (68.28) lsd (0.05) 5.53 7.30 9.20 cv (%) 3.68 5.51 7.20 values in parenthesis indicate % values of control proline content the effect of water stress on proline content of the genotypes varied significantly at 15, 30 and 45 days after drought imposition (table 2). at 15 days, the highest proline content in control condition was in bari soybean 5 and water stress in binasoybean 1, while the lowest was in bu soybean. relative (per cent of control) proline content of the genotypes ranged from 108.82 to 144.02% under water stress. highest relative proline content was obtained from binasoybean 1 (144.02%), followed by galarsum (119.97%) and bu soybean 1 (110.73%) and it was lowest in bari soybean 5 (108.82%). the increase of proline content due to water stress was higher in binasoybean 1 (144.02%), while that was lower in bari soybean 5 (108.82%). at 30 days, the proline content both in control and water stress was recorded highest in galarsum and binasoybean 1, respectively, while the lowest was in bu soybean1. relative (per cent of control) proline content of the genotypes ranged from 148.46 to 355.18% at water stress. highest relative proline content was obtained from binaoybean 1 (355.18%), followed by bu soybean 1 (201.92%) and galarsum (198.50%) and it was lowest in barisoybean 5 (148.46%). the increase of the proline content due to water stress was higher in binasoybean 1, while that was lower in bari soybean 5. at 45 days, the proline content at water stress was recorded highest in binasoybean 1. relative (per cent of control) proline content of the genotypes ranged from 96.12to 186.66% under water stress. highest relative proline content was obtained from binasoybean 1 (186.66%), followed by bari soybean 5 (116.37%) and bu soybean 1 (105.93%) and lowest in galarsum (96.12%). the increase of the proline content due to water stress was higher in binasoybean 1, while that was lower in galarsum. the proline accumulation is a metabolic response characteristic of plants under abiotic stresses, it being showed the increase in this experiment because the free proline work as osmotic adjustor that reduce the negative effects provoked in the plants under adverse conditions (kishor et al.,1995), besides promote higher resistance in cells under these circumstances (zhu and xiong, 2002). the proline is synthesized from glutamate and ornitine, in which the production of this organic solute, under conditions of the water shortage, occur at major part from glutamate (delauney and verma, 1993). table 2. leaf proline content (mg g-1 fresh weight) of soybean genotypes as affected by water stress at different days after water stress (daws) 15 daws 30 daws 45 dawsgenotypes cont rol water stress control water stress control water stress bu soybean 1 1.77 1.96 (110.73) 1.04 2.10 (201.92) 1.18 1.25 (105.93) binasoybean 1 1.84 2.65 (144.02) 1.27 4.51 (355.18) 0.90 1.68 (186.66) galarsum 1.88 2.25 2.00 3.97 1.29 1.24 74 sarkar et al. (119.97) (198.50) (96.12) bari soybean 5 2.04 2.22 (108.82) 1.96 2.91 (148.46) 1.16 1.35 (116.37) lsd (0.05) 0.59 2.94 0.56 cv (%) 16.33 11.59 12.56 values in parenthesis indicate % values of control malondialdehyde (mda) content the malondialdehyde (mda) content of the genotypes was significantly affected by drought at 15 days after water stress (table 3). the malondialdehyde (mda) content in control was highest in galarsum, while the lowest in bari soybean 5. relative (per cent of control) mda content of the genotypes ranged from 116.21 to 140.86% at water stress. highest relative mda content was obtained from bu soybean 1 (140.86%), followed by bari soybean 5 (137.23%) and galarsum (120.71%) and lowest in binasoybean 1 (116.21%). the increase of mda content due to water stress was higher in bu soybean 1, while that was lower in binasoybean 1. at 30 days after drought imposition, the mda content under water stress was recorded highest in bari soybean 5, while the lowest was in binasoybean 1. relative (per cent of control) mda content of the genotypes ranged from 125.26to 149.69% at 50% field capacity. highest relative mda content was obtained from bari soybean 5 (149.69%), followed by galarsum (142.91%) and bu soybean 1 (134.04%) and lowest in binasoybean 1 (125.26%). the increase of mda content due to water stress was higher in bari soybean 5, while that was lower in binasoybean 1. at 45 days, the mda content was recorded highest in bu soybean 1, while the lowest in bari soybean 5. relative (per cent of control) mda content of the genotypes ranged from 111.78to 121.94%. the maximum relative mda content was obtained from bari soybean 5 (121.94%), followed by galarsum (117.73%) and binasoybean 1 (111.86%) and it was lowest in bu soybean 1 (111.78%). the increase of mda content due to water stress was higher in bari soybean 5, while lower in bu soybean 1. the relative mda content was significantly higher in water stress condition than control in all the genotypes in the present investigation, the lower relative values of mda in binasoybean 1 indicate that at cellular level this genotype is better equipped with efficient free radical quenching system that offers protection against oxidative stress. total sugar content the effect of water stress on total sugar content varied significantly at 15 days after drought imposition (table 4). the total sugar content in control condition was higher in bari soybean 5 while the lowest in binasoybean 1. relative sugar content (per cent of control) of the genotypes ranged from 104.15 to 136.03% at water stress condition. table 3. malondialdehyde (mda) (nmol g-1fresh weight) content of soybean genotypes as affected by water stress at different days after water stress (daws) 15 daws 30 daws 45 dawsgenotypes control water stress control water stress control water stress bu soybean 1 11.50 16.20 (140.86) 18.65 25.00 (134.04) 49.65 55.50 (111.78) binasoybean 1 13.20 15.34 (116.21) 19.95 24.99 (125.26) 44.92 50.25 (111.86) galarsum 14.00 16.90 (120.71) 18.55 26.51 (142.91) 43.59 51.32 (117.73) bari soybean 5 11.20 15.37 (137.23) 19.36 28.98 (149.69) 40.28 49.12 (121.94) lsd (0.05) 4.12 ns 8.84 cv (%) 11.21 10.56 8.55 values in parenthesis indicate % values of control 75 physiological basis of water stress tolerance in soybean the maximum relative total sugar content was obtained from binasoybean 1 (136.03%), followed by galarsum (131.74%) and bu soybean 1 (105.65%) and lowest in bari soybean 5 (104.15%). at 30 days, the sugar content in control condition was recorded highest in bu soybean 1, while the lowest in binaoybean 1. relative (per cent of control) sugar content of the genotypes ranged from 116.69 to 193.44.11% at water stress condition. highest relative total sugar content was obtained from binasoybean 1 (193.44%), followed by galarsum (188.62%) and bu soybean 1 (123.81%) and lowest in bari soybean 5 (116.69%). the increase of the sugar content due to water stress was higher in the binaoybean 1, while lower in bari soybean 5 (116.58%). the effect of water stress was not significant at 30 days after drought imposition. at 45 days after, the sugar content in control condition was recorded highest in galarsum, while the lowestin binasoybean 1. relative sugar content of the genotypes ranged from 117.63 to 136.46% at water stress while while binasoybean 1 (136.46%), followed by galarsum (124.01%) and bu soybean 1 (122.36%) and lowest in bari soybean 5 (117.63%). . the total soluble sugars content in soybean leaves significantly increased under drought stress. these results are in accordance with abass and mohamed (2011) who reported that the drought condition caused significant increase in the soluble sugars content in shoot of common bean plants. table 4. total sugar content (mg g-1 fresh weight) of soybean genotypes as affected by water stress at different days after water stress (daws) 15 daws 30 daws 45 dawsgenotypes control water stress control water stress control water stress bu soybean 1 43.12 45.57 (105.65) 42.11 52.14 (123.81) 67.51 82.79 (122.63) binasoybean 1 37.75 51.35 (136.03) 24.40 47.20 (193.44) 65.39 89.23 (136.46) galarsum 38.72 51.00 (131.74) 26.64 50.25 (188.62) 79.19 98.21 (124.01) bari soybean 5 44.96 46.83 (104.15) 33.85 39.50 (116.69) 75.24 88.52 (117.63) lsd0.05 10.93 ns 36.20 cv (%) 10.27 12.10 15.04 values in parenthesis indicate % values of control number of pod the highest number of pod/plant under control was recorded in galarsum (81.67) and the lowest in bu soybean 1 (57.33). on the other hand, under water stress condition binasoybean 1 produced the highest number of pod/plant (43.67) and the lowestin bari soybean 5 (26). relative number of pod / plant of the genotypes ranged from 34.06to 65.27% at water deficit condition. the maximum relative number of pod / plant was obtained from binasoybean 1 (65.27%), followed by bu soybean 1 (64.53%) and galarsum (38.36%) and lowest in bari soybean 5 (34.06%). the significant reduction in number of harvested pod/plant under water stress may be attributed to the abscission of the reproductive structures. ziska and hall (1983) and gwathmey and hall (1992) reported similar results. number of seed the highest number of seed/pod under control was recorded from bu soybean 1 (2.03) and the lowest in bina soybean 1 (1.99). on the other hand, under water stress condition binasoybean 1 produced the highest number of seed/pod (1.89) and the lowest from bari soybean 5 (1.59). relative (percent of control) number of seed/pod of the genotypes ranged from 78.71 to 94.97% at water deficit condition. highest relative number of seed/pod was obtained from oybean 1 (94.97%), followed by 76 sarkar et al. bu soybean 1 (90.15%) and galarsum (81.19%) and lowest in bari soybean 5 (78.71%). the reduction in number of seed/pod and seed size under water stress treatments may be attributed to the limitation of dry matter partitioning to the reproductive sink or even seed formation factors as has been reported by turk et al. (1980). 100-seed weight the highest seed weight both under control and water stress condition was recorded in binasoybean 1 (11.76 g and 10.26 g) and the lowest in bari soybean 5 (11.21 g and 7.11 g). relative weight of 100 -seeds of the genotypes ranged from 63.43 to 87.24% at water deficit condition. highest relative weight of 100seeds was obtained from binasoybean 1 (87.24%), followed by galarsum (86.79%) and bu soybean 1 (67.01%) and lowest in bari soybean 5 (63.43%). table 5. seed yield and yield contributing parameters of soybean genotypes as affected by water stress number of pod / plant number of seed / pod 100-seed weight (g) seed yield (g/plant)genotypes control water stress control water stress control water stress control water stress bu soybean 1 57.33 37.00 (64.53) 2.03 1.83 (90.15) 11.55 7.74 (67.01) 13.07 5.41 (41.39) bina soybean 1 71.67 46.78 (65.27) 1.99 1.89 (94.97) 11.76 10.26 (87.24) 15.54 6.52 (41.96) galarsum 81.67 31.33 (38.36) 2.02 1.64 (81.19) 11.66 10.12 (86.79) 17.28 5.56 (32.18) bari soybean 5 76.33 26.00 (34.06) 2.02 1.59 (78.71) 11.21 7.11 (63.43) 15.67 4.59 (29.29) lsd (0.05) 10.56 0.24 1.14 2.28 cv(%) 11.74 7.57 6.44 12.64 values in parenthesis indicate % of control seed yield the highest yield under control condition was recorded in galarsum (17.28 g) and the lowest in bu soybean 1(13.07 g). on the other hand, under water stress condition binasoybean 1 produced the highest yield (6.52 g) and the lowest in bari soybean 5 (4.59 g). highest relative yield was obtained from binasoybean 1 (41.96%), followed by bu soybean 1 (41.39%) and galarsum (32.18%) and lowest in bari soybean 5 (29.29%). the reduction of the yield per plant due to water stress was lower in binasoybean 1 (58.04%), while higher in bari soybean 5 (70.71%). drought stress in soybean reduced total seed yield and the branch seed yield (frederick et al., 2001). in the present study, the reduction in seed yield under water stress was associated with number of pods per plant, number of seeds per pod and seed weight. conclusion soybean var. binasoybean 1 showed relatively higher water stress tolerance in respect of yield compare to other genotypes . higher water content, proline and sugar accumulation in leaf as well as lower accumulation of malondialdehyde (mda) contributed to the higher drought tolerance in binasoybean 1 compare to other genotypes. acknowledgement 77 physiological basis of water stress tolerance in soybean the research was carried out with the financial support of research management committee (rmc), bsmrau. references abass, s. m. and h. i. mohamed. 2011. alleviation of adverse effects of drought stress on common bean (phaseolus vulgaris l.) by exogenous application of hydrogen peroxide. bangladesh j. bot. 40 (1): 75-83. arora, a., r. k. sairam and g. c. srivastava. 2002. oxidative stress and antioxidative systems in plants. curr. sci. 82: 1227-1238. bates, l. s., r. p. waldren and l. d. teare. 1973. rapid determination of free proline for water-stress studies. short communication. plant and soil. 39 (1): 205-207. delauney, a. j. and d. p. s. verma. 1993. proline biosynthesis and osmoregulation in plants. plant j. 4(2): 215-223 farooq, m., a. wahid, n. kobayashi, d. fujita, and s. m. a. basra, 2009. plant drought stress: effects, mechanisms and management. agronomy for sustainable development. 29: 185-212. frederick, j. r., c. r. camp and p. j. bauer. 2001. drought-stress effects on branch and mainstem seed yield and yield components of determinate soybean. crop sci. 759-763. fuhrer, j. 2003. agroecosystem responses to combinations of elevated co2, ozone, and global climate change. agric. ecosyst. environ. 97: 1-20. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research (2nd edition). international rice research institute. john willey and sons, inc. singapore, pp. 139-240. gwathmey, c. o. and a. e. hall. 1992. adaptation to mid-season drought of cowpea genotypes with contrasting senescence traits. crop sci. 32: 773-778. heath, r. l. and l. packer. 1968. photoperoxidation in isolated chloroplasts. i. kinetics and stoichiometry of fatty acid peroxidation. arch biochem bioph. 125: 189-198. kishor, p. b. k., z. hong, g. miao, c. a. a. hu and d. p. s. verma. 1995. over expression of 1pyrroline-5carboxylate synthetase increases proline over production and confers osmotolerancein transgenic plants. plant physiol. 108(4): 1387-1394. moussa, h. r. 2011. low dose of gamma irradiation enhanced drought tolerance in soybean. acta agron hung. 59: 1-12. rohbakhsh, h. 2013. alleviating adverse effects of water stress on growth and yield of forage sorghum by potassium application. advances environ biol. 7(1): 40-46. schonfeld , m. a., r. c. johnson, b. f. carver and d. w. mornhinweg. 1988. water relations in winter wheat as drought resistant indicator. crop sci. 28: 526-531. somogyi, h. 1952. notes on sugar determination. j. biol. chem. 195: 19-23. turk, k. j. and a. e. hall. 1980. drought adaptation of cowpea. iv: influence of drought on water use and relation with growth and seed yield. agron. j. 72: 440-448. velu, g. and k. palanisami. 2002. impact of moisture stress on growth and yield of sunflower. madras agric. j. 88 (10-12): 660-665. verslues, p. e., m. agarwal, s. katiyar-agarwal, j. zhu and i. k. zhu. 2006. methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status. the plant j. 45(4): 523-539. 78 sarkar et al. zhu, j. k. and l. xiong. 2002. molecularand genetic aspects of plant responses to osmotic stress. plant cell and environ. 25(2): 131-139. ziska, l. h. and a. e. hall. 1983. seed yields and water use of cowpea (vigna unguiculata [l.] walp.) subjected to planned-water deficit irrigation. irrig. sci. 3: 237-245. impacts of environmental change and management practices on phonological events and yield of mustard at different sowing dates bangladesh agron. j. 2015, 18(2): 45-52 impact of sowing date induced temperature and management practices on development events and yield of mustard m.s.a. khan and m.a. aziz agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh corresponding author: shawquatshahadat@yahoo.com key words: brassica spp., temperature, growing degree days, productivity abstract the experiment was conducted at the research field of the agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur, during rabi season of 2014-2015 to find out the relationship between different development events of mustard crop and sowing dates induced temperature as well as to minimize the yield reduction of the crop by adopting appropriate management practices. the mustard var. bari sarisha-15 was sown on 06, 25 november and 14 december 2014. crop accumulated lower growing degree days (gdd) i.e., 72.15, 521.10 and 1070 to 1154 °c were observed for the events of emergence, 50 % flowering and maturity on 14 december sowing. late sown plants took minimum time from flowering to maturity (36 days) due to increased temperature and high variability in both maximum and minimum temperature. the highest seed yield (1569 kg ha-1) was recorded from 06 november sowing with high management practices while the lowest seed yield (435 kg ha-1) from 14 december sowing with low management practices. at high management practices the crop yielded 1183 kg ha-1 at 14 december sowing. yield reduction at late sowing condition was reduced to some extent with high management practices. the seed yield reductions at 14 december sowing as compared to high management practices at 06 november sowing were 72, 43 and 25% under low, medium and high management, respectively. introduction agriculture is one of the most vulnerable sectors to the climate change impact in bangladesh. climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity (ipcc, 2007). ipcc reported that the area averaged annual mean warming will be around 3°c in the decade of 2050s and around 5°c in the decade of 2080s over land part of asiatic region. this change may alter the geographical distribution and growing season of agricultural crops (porter, 2005). among the different climatic factors temperature adversely affects crops especially winter crops in bangladesh. mustard is one of the major oil seed crops in bangladesh. its grows in temperature between 10°c and 30°c, but the optimum temperature for growth of brassica napus and brassica rapa species is about 20°c (thomas, 1984). in bangladesh, it is grown under different environmental situations such as timely or late sown, with or without fertilizer and rainfed or irrigated conditions. it is mostly grown after t. aman rice in rice based cropping pattern. since, mustard is grown in winter season and winter is becoming shorter due to climate change, the growth of the crop may be affected by the climate change . high temperature in brassica enhanced plant development and caused flower abortion with significant loss in seed yield (rao et al., 1992). most of the cultivated soils have growth limiting problems associated with mineral-nutrient deficiencies (cakmak, 2002). nitrogen fertilization has been reported to mitigate the adverse effects of abiotic stress (waraich et al., 2011). on the other hand potassium plays a crucial role in survival of crop plants under 46 khan et al. environmental stress conditions (munns, 2005). however, it is necessary to determine the relationship between different development events of the crop and the prevailing temperature for the development of appropriate management option to minimize the yield reduction. therefore, this study was done to analyze the impacts of sowing date induced temperature and management practices on development events and yield of mustard. materials and methods the experiment was conducted at the research field of the agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur, during rabi season of 20142015. the location of the experimental site is situated at about 230 59´ north latitude, 900 24´ east longitudes and an altitude of 8.4 m above sea level. the soil was silty clay in texture with ph of 6.5. the experiment was laid out in a split-plot design with three replications. the sowing dates were: i. 06 november (timely), ii. 25 november (late) and iii. 14 december (too late); while the management practices were: i. low: 60-15-30-10 kg npks/ha, no irrigation, no weeding, no pesticide. ii. medium: 80-25-60-20 kg npks/ha, one weeding at 21 dae, two irrigations at rosset and flowering stages & spraying pesticides, and iii. high: 120-35-90-30 kg npks/ha, one weeding at 21 dae, two irrigations at rosset and flowering stages, & spraying pesticides. the sowing dates were assigned in the main plots and management practices in sub-plots. the mustard var. bari sarisha-15 was used as a test crop. seeds were sown in lines with maintaining 30 cm row to row spacing. half of urea and full doses of other fertilizers were applied at the time of final land preparation. the remaining half of urea was top dressed at vegetative and flowering stage followed by irrigation. in case of low management, all fertilizers were applied at the time of final land preparation. insecticide and fungicide were sprayed in the respective treatment plots. admire 200sl @ 1 ml/liter of water was sprayed at 20 and 35 dae to control jassids and white flies. rovral-50 wp @ 2 g/liter of water was sprayed at 30 and 45 dae to control alternaria diseases. daily temperatures were recorded for computing required growing degree days (gdd) for different stages. gdd were computed by using daily normal maximum air temperature, minimum air temperature, mean air temperature and considering base temperature of 5º c for mustard (singh et al., 2014). the sum of degree days for the completion of different development stage of mustard were obtained by using the following formula (kumar et al., 2008); accumulated gdd (º c day) = summation (daily mean air temperature in º c – base temperature of mustard). at flowering stage, plant samples were collected from an area of one square meter of all treatments and different plant parts of the collected samples were separated and then oven dried at 70 ºc for 4 days to measure the dry weight. at harvest, yield contributing characters were recorded from selected five plants and yield data were recorded by harvesting one square meter area. data were analyzed by mstat-c and means were compared using least significant difference (lsd). results and discussion days for development events total number of days required for different development events of mustard grown under different sowing dates and management practices are presented in table 1. all developmental events varied due to variations in sowing dates and management practices. the events of emergence, first flowering and 50% flowering did not differ by management practices but differed by sowing dates. the crop sowm on 25 november took maximum days (6) for emergence and the minimum days (4 days) on 06 november 2014 december sowing took maximum days (34 ) for first flowering and 50% flowering (38 days), whereas crop 47 impact of sowing date induced temperature and management sown on 06 november took minimum days (29) for first flowering and 50% flowering (35 days). the days for maturity varied by sowing date and management practices. sown on 06 november took maximum days (80 to 83), while that of 14 december took the minimum days for maturity (74 to 78). crop with low management practices took minimum days for maturity while medium and high management practices took maximum days. the minimum day (74) for maturity was found in plants of 14 december sowing at low management practices. plants developed from both the medium and high management practices took similar days for maturity at each sowing date. table 1. total number of days required for different developmental events of mustard grown at different sowing dates under different management practices treatments developmental events sowing dates management emergence first flowering 50% flowering maturity low 4 29 35 80 medium 4 29 35 83 06 nov. high 4 29 35 83 low 6 33 39 79 medium 6 33 39 83 25 nov. high 6 33 39 83 low 5 34 38 74 medium 5 34 38 78 14 dec. high 5 34 38 78 temperatures and development events both maximum and minimum temperatures were higher at 06 november sowing that reduced the number of days for emergence and first flowering (table 2). the higher maximum temperatures for emergence and flowering were 33.0 ± 0.94 °c and 29.0 ± 1.80 °c and minimum were 21.9 ± 2.35 °c and 16.1 ± 2.20 °c, respectively. table 2. prevailing temperature during different development events of mustard grown at different sowing dates under different management practices during rabi season, 2014-2015 maximum temperature (°c) minimum temperature (°c)developmental events sowing dates range mean ± sd range mean ± sd 06 november 32.2 34.0 33.0 ± 0.94 19.5 25.0 21.9 ± 2.35 25 november 26.5 28.8 27.5 ± 0.72 13.6 15.0 14.3 ± 0.57 sowing to emergence 14 december 20.7 27.8 24.4 ± 2.82 13.0 17.0 14.5 ± 2.06 06 november 26.5 34.0 29.0 ± 1.80 13.6 21.2 16.1 ± 2.20 25 november 15.6 28.8 24.5 ± 3.54 11.0 17.0 13.7 ± 1.94 emergence to first flowering 14 december 15.6 30.0 24.8 ± 3.26 9.8 19.7 13.0 ± 3.07 06 november 22.3 28.8 24.9 ± 2.98 12.5 17.0 15.0 ± 1.96 25 november 21.2 29.4 24.5 ± 2.45 11.0 19.2 12.1 ± 1.99 first flowering to 50% flowering 14 december 15.5 26.7 19.4 ± 5.09 12.0 15.3 13.0 ± 1.54 06 november 15.5 30.0 24.3 ± 3.52 9.8 19.7 13.2 ± 2.65 25 november 15.5 30.0 29.6 ± 2.39 9.8 19.7 15.7 ± 3.05 50 % flowering to maturity 14 december 20.5 33.0 27.6 ± 2.45 10.0 21.0 14.1 ± 3.28 due to high variability in maximum temperature (range: 15.5 – 26.7 °c, mean: 19.4 ± 5.09 °c) 14 december sowing took minimum days from first flowering to 50 % flowering. from 50% flowering to maturity, temperatures were lower at 06 november sowing (max.) that increased the number of days for maturity. average maximum and minimum temperatures for 50% flowering to maturity were higher in 25 november sowing than 14 december 48 khan et al. sowing. the maximum and minimum temperatures ranged from 15.5 – 30.0 °c and 9.8 – 19.7 °c for 25 november sowing and 20.5 – 33.0 °c and 10.0 – 21.0 °c 14 december sowing, respectively. the high variability in both maximum and minimum temperature induced by 14 december sowing enhanced maturity of the mustard crop (fig. 1). 0 5 10 15 20 25 30 35 14 33 5 14 33 9 14 34 3 14 34 7 14 35 1 14 35 5 14 35 9 14 36 3 15 00 1 15 00 5 15 00 9 15 01 3 15 01 7 15 02 1 15 02 5 15 02 9 15 03 3 15 03 7 15 04 1 15 04 5 15 04 9 15 05 3 15 05 7 t em pe ra tu re ( °c ) julian days min max flowering 14343 14362 15016 09 dec 28 dec 17 jan fig. 1. prevailing temperature from flowering to maturity of mustard grown at different sowing dates (arrows indicate starting of flowering for different sowing dates). growing degree days for development events the accumulated growing degree days (gdd) required for different development events of mustard varied under different sowing dates and management practices (table 3). among the different dates of sowing, 06 november sowing accumulated maximum gdd of 89.70, 591.35 and 665.25 °c for the events of emergence, first flowering and 50% flowering, respectively. the minimum accumulated gdd of 72.15 and 521.10 °c were observed for the events of emergence and 50% flowering at 14 december sowing, respectively. for maturity stage of the mustard plants, the maximum accumulated gdd (1284.35 to 1323.65°c) was recorded on 06 november sowing and the minimum (1070.20 to 1154.20°c) on 14 december sowing. the gdd also varied under different management practices of mustard at maturity. the minimum gdd was observed for maturity under low management practices at all dates of sowing. total dry matter total dry matter production at flowering and their distribution in different plant parts under different sowing dates and management practices (fig. 2). the highest total dry matter (93 g m-2) was recorded in plants of 06 november sowing with high management, which was identical with medium management practices at the same date of sowing. the lowest total dry matter (9 g m-2) was recorded at 14 december sowing with low management practices. table 3. accumulated growing degree days (°c) for different developmental events of mustard grown at different sowing dates under different management during rabi season, 2014-2015 treatments developmental events sowing dates management emergence first flowering 50% flowering maturity 49 impact of sowing date induced temperature and management low 89.70 591.35 665.25 1284.35 medium 89.70 591.35 665.25 1323.65 06 nov. high 89.70 591.35 665.25 1323.65 low 95.45 475.45 564.50 1115.90 medium 95.45 475.45 564.50 1172.55 25 nov. high 95.45 475.45 564.50 1172.55 low 72.15 476.3 521.10 1070.20 medium 72.15 476.3 521.10 1154.20 14 dec. high 72.15 476.3 521.10 1154.20 0 20 40 60 80 100 low medium high low medium high low medium high d ry m at te r (g m -2 ) management practices stem leaf flower c a a d bcbc d d b 06 nov 25 nov 14 dec fig. 2. dry matter production at flowering and their distribution in different plant parts under different management practices at different sowing dates under low management practices the total dry matter produced from 25 november and 14 december sowing was identical. the highest dry matter accumulation in stem (52 g m-2), leaf (31.6 g m-2) and flower (9.6 g m-2) was recorded at 06 november sowing with high management practices and the lowest dry matter in stem (4.4 g m-2), leaf (3.6 g m-2) and flower (1.2 g m-2) at 14 december sowing with low management practice. it might be due to prevailing high temperature at flowering stage that increased photo-respiration and reduced net photosynthesis resulted in lower dry matter production (sage and sharkey, 1987). wellmanaged plants grown at late and high temperature showed higher dry matter production than poor managed one probably due to higher balanced between photorespiration loss and production of photosynthates. yield and yield attributes plant populations, plant height, number of branches plant-1, number of siliqua plant-1, seeds siliqua-1, 100-seed weight and seed yield of mustard showed significant difference in different sowing dates and management practices (table 4). the highest population (70 plant m-2) was recorded from 14 december sowing with low management practices and the lowest (52 plant m-2) from 06 november sowing with same management practices. the tallest plant was recorded from 06 november sowing with high management practices (108.20 cm), which was identical with medium management practices at the same date of sowing (99.50 cm) and high management practices at 25 november sowing (101.60cm). the minimum plant was recorded from 14 december sowing with low management practices (69.93 cm). significantly the highest number of branches was recorded from 06 november sowing with high management practices (8 plant-1). the lowest branches were recorded at 25 november sowing with low management practices. sown on 06 november sowing with high management practices also produced the maximum number of siliqua (84 plant-1) which was followed by medium management practices at the same date of sowing (70 plant-1) and 50 khan et al. high management practices at 25 november sowing (67 plant-1). the lowest number of siliqua was recorded from 14 december sowing with low management practices (19 plant-1). high temperature at flowering and siliqua formation stages enhanced flower and siliqua abscissions that reduced the number of siliqua (sinaki et al., 2007). the maximum reduction in siliqua at 14 december sowing could be due to floral sterility caused by high temperature (morrison and stewart, 2002). seed yield of mustard varied significantly under different sowing dates and management practices. the maximum seed yield also recorded from 06 november sowing with high management (1569 kg ha-1) which was identical with high management practices at 25 november sowing (1534 kg ha-1). the lowest seed yield was obtained from 14 december sowing with low management practices (435 kg ha-1) whereas at high management practices crop yielded 1183 kg ha-1. high temperature during reproductive phase is a primary constraint to its production. the lower seed yield at 14 december sowing might be due to prevailing high temperature (fig. 1) during flowering to maturity. the results are in agreement with the findings of rao et al. (1992). seed yield reduction of mustard varied from timely sowing to different sowing dates under different management (table 4). table 4. yield contributing characters and yield of mustard grown at different sowing dates under different management practices during rabi season, 2014-2015 treatments sowing dates management plant population (m-2) plant height (cm) branches plant-1 (no.) siliqua plant-1 (no.) seeds siliqua-1 (no.) 100seed wt (g) seed yield (kg ha1) 06 nov. low 52 77.33 3.8 26.0 19 0.29 620 medium 56 99.50 6.4 70.0 20 0.30 1245 high 52 108.2 7.8 83.8 24 0.31 1569 25 nov. low 67 72.20 1.3 20.3 20 0.29 583 medium 61 94.07 5.2 43.7 23 0.30 1060 high 59 101.6 5.5 67.4 23 0.31 1534 14 dec. low 70 69.93 2.5 18.9 18 0.29 435 medium 61 77.40 3.9 34.3 21 0.31 889 high 63 83.27 4.5 55.7 21 0.31 1183 lsd (0.05) 6.05 10.37 0.70 13.35 ns ns 155.5 cv (%) 5.68 6.69 8.62 16.07 7.90 5.31 8.63 seed yield reductions at 14 december sowing compared to 06 november sowing under low, medium and high management practices were 30, 29 and 25%, respectively. the seed yield reductions were 72, 43 and 25% under low, medium and high management at 14 december sowing, respectively compared to high management practices at 06 november sowing. better seed yield in well-managed plants at 14 december sowing could be due to higher accumulation of compatible osmolytes which might helped to increase water retention in plants for better stomata regulation and increased photosynthesis. conclusion from the above findings, it may be concluded that mustard crop is vulnerable to sowing dates induced temperature variability. developmental events were badly affected due to late sowing of seeds on 14 december. yield reduction may be reduced to some extent through 51 impact of sowing date induced temperature and management adopting high management practices. the highest seed yield (1569 kg ha-1) was recorded from 06 november sowing with high management practices while the lowest seed yield (435 kg ha-1) from 14 december sowing with low management practices. at high management practices the crop yielded 1183 kg ha-1 at 14 december sowing. yield reduction at late sowing condition was reduced to some extent with high management practices. references aggarwal, p. k., 2003. impact of climate change on indian agriculture. plant biology, 30, pp.189198. angadi, s. v., h. w. cutforth, b. g. mcconkey and y. gan. 2003. yield adjustment by canola grown at different plant populations under semiarid conditions. crop science. 43: 13581366. bbs (bangladesh bureau of statistics). 2013. statistical yearbook of bangladesh. bangladesh bureau of statistics, statistics division, ministry of planning, govt. people’s republic of bangladesh. cakmak, i. 2002. plant nutrition research: priorities to meet human needs for food in sustainable ways. plant soil. 247: 3-24. ipcc, 2007. climate change 2007. impacts, adaptation and vulnerability. working group ii contribution to fourth assessment report of the intergovernmental panel on climate change. m.parry, o.canziani, j.palutikof, p.v.d.linden and c.hanson, eds., cambridge university presss, cambridge, pp.1-976. kalra, n., p. k. aggarwal, s. chander, h. pathak, r. choudhary, a. choudhary, s. mukesh, h. k. rai, u. a. soni, s. anil, m. jolly, u. k. singh, a. owrs and m. z. hussain, 2003. impacts of climate change on agriculture. climate change and india: vulnerability assessment and adaptation. in: shukla, p. r., s. k. sharma, n. h. ravindranath, a. garg and s. bhattacharya, eds., orient longman private ltd., hyderabad, pp.193-226. kumar, a., v. pandey, a. m. shekh and m. kumar. 2008. growth and yield response of soybean (glycine max l.) in relation to temperature, photoperiod and sunshine duration at anand, gujarat, india. am-euras. j. agron., 1(2): 45-50. morrison, m. j. and d. w. stewart. 2002. heat stress during flowering in summer brassica. crop science. 42: 797-803. munns, r. 2005. genes and salt tolerance: bringing them together. tansley review. new phytol. 645-656. porter, j. r. 2005. rising temperatures are likely to reduce crop yields. nature: 436, 174. radin , j. w. and m. a. matthews. 1989. water transport properties of cortical cells in roots of nitrogen and phosphorus deficient cotton seedlings. plant physiol. 89: 264-268. rao, g. u., a. jain and k. t. shivanna. 1992. effect of high temperature stress on brassica pollen: viability, germination and ability to set fruits and seeds. ann. bot. 69: 193-198. sage, r. f. and t. d. sharkey. 1987. the effect of temperature on the occurrence of o2 and co2 insensitive photosynthesis in field grown plants. plant physiol. 84: 658-664. sinaki, j. m., e. majidi heravan, a. h. shirani rad, g. nour mohammadi and h. zarei. 2007. the effects of water deficit during growth stages of canola (brassica napus l.). amercaneurasian journal of agricultural and environmental sciences. 2(4): 417-422. 52 khan et al. singh, m. p., lallu and n. b. singh. 2014. thermal requirement of indian mustard (brassica juncea) at different phonological stages under late sown condition. indian j. plant physiol. 19(3): 238-243. thomas, p. 1984. canola growers’ manual. canola council of canada. 301-433. main st., winnipeg. canada. waraich, e. a., r. ahmad, m. ashraf, y. saifullah and m. ahmad. 2011. improving agricultural water use efficiency by nutrient management in crop plants. acta agriculturae scandinavica, section bsoil & plant sci. 61(4): 291-304 bangladesh agron. j. 2014, 17(1): 59-66 source-sink manipulation and population density effects on fodder and grain yield of hybrid maize shah-al-emran, k. m. s. haque, q. a. khaliq and m. y. miah1 department of agronomy,1 department of soil science, bangabandhu sheikh mujibur rahman agricultural university, gazipur1706, bangladesh corresponding author: s.emran@cgiar.com key words: source-sink, fodder, hybrid maize and bcr abstract an experiment was carried out in the field laboratory at the bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh, during rabi season of 2009-2010. planting material was maize var. bari hybrid maize 7.three levels of population density (66667, 83333 and 111111 plants ha-1) and four source-sink manipulation, viz. removed all leaf blades below the lower most cob, removed tassel and all leaf blades below the lower most cob, removed all leaf blades except those adjacent to cob and no clipping, were imposed at silking stage. during crop growth, removal of all leaf blades below the cob showed less adverse effect on grain yield and yield parameters and the leaves so removed can be used as green fodder. removal of tassel and all leaf blades except those adjacent to cob showed adverse effect on grain yield and yield parameters. complete defoliation severely reduced grains on cob. the highest gross return and benefit cost ratio (bcr) was obtained from the treatment having 1,11,111 plants ha-1 with no clipping while the lowest from the treatment with removal of all leaf blades excluding those adjacent to cob in 66667 plants ha-1. in case of dual purpose, 1,11,111 plants ha-1 with removal of tassel and all leaf blades below the lower most cob gave the highest gross return but 66667 plants ha-1 with removal of all leaf blades below the lower most cob gave the highest bcr (1.78) introduction maize (zea mays) is a major crop used as food, feed, fuel and a source of carbohydrate, oil, protein and fiber. dry-matter production and grain yield are limited by the source–sink affiliation of crop assimilates and the end nutrient availability in the grain is expected to be constrained by the sink capacity as well as by the contribution of source (zhang et al., 2012).various ways of leaf clipping have influences on dry matter accumulation and grain yield. it was reported that tassel clipping two days after silking, generally increases the grain yield at 6.7 percent more than the control due to increased grain weight (wang, 1996). leaf clipping of upper three leaves at 2 and 16days after tasseling, decreases grain yield by 24 and 9 percent, respectively (wang, 1996). when leaf clipping done at the primary stage of grain development, the grain yield decrease would arise due to increased grain number (wang, 1996). leaf clipping at early season significantly reduces both the stem length and leaf area; however, it did not have any effect on leaf emergence. also, leaf clipping at early season decreased soluble grain carbohydrate in order to devote the carbohydrates for vegetative growth and reduce sucrose sources (prioul and dugue, 1992). it was noticed that when the defoliation was severe and its time was closer to silking stage, forage yield and soluble sugars decreased greatly (burton, 2004). the effect of leaf defoliation on canopy photosynthesis and changing the sink and source carbohydrates showed that soluble sugars in plants with leaf clipped (control, above ear leaf clipping, below ear leaf clipping and full leaf clipping at flowering stage) was different (egile, 2000). it was observed that full leaf clipping treatment made the most decrement of canopy photosynthesis and changing the sink and source carbohydrates and the percentage of soluble sugar in different parts of plant such as grains (egile, 2000). the grains of plants which had limitation on their sinks were not able to use possible carbohydrates (burton, 2004). cultivar and leaf clipping treatments had significant effects on grain yield, 60 emran et al. globulin, glutenin, prolamine, albumin and soluble carbohydrates. the grain yield is mostly observed in above ear leaf clipping treatment which is followed by ear leaf clipping and below ear leaf defoliation. grain yield is a function of dry mass production and harvest index. yield is mostly related with its dry matter production ability. for a genotype, generally the higher the dry matter accumulation, the greater is the yield under favorable condition. however, there is little information on the interaction between leaf clipping and planting density to grain and fodder yield of maize. this study was undertaken to elucidate the effect of different levels of leaf clipping and population density on grain yield and yield attributing characters and green fodder yield of maize. materials and methods a field experiment was conducted in research field of bangabandhu sheikh mujibur rahman agricultural university (latitude: 24° 09' n., longitude: 90° 25’ e., and 8.4 meters above sea level) in winter 2009-10, to study the relations between source-sink manipulation and population density in corn plants. the soil of the experimental site was silty clay loam (clay of 35.6%, sand of 17.2%, and silt of 47.2%) with ph 5.6, and organic carbon of 0.65%. the experiment was conducted in a randomized complete block design with three replications. a total of three population densities viz. 66,667 (75 cm x 20 cm), 83,333 (60 cm x 20 cm) and 1,11111 (60 cm x 15 cm) plants ha-1 and four leaf & tassel clippings were used in this experiment. among the clipping treatments, no clipping was treated as control (c1), with other three levels, i.e. removal of all leaf blades below the lowermost cob (c2), removal of tassel and all leaf blades below the lowermost cob (c3) and removal of all leaf blades except those adjacent to cob (c4). the seeds of bari hybrid maize-7 were planted by maintaining different population density, as mentioned above, and clipping treatments were applied during silking stage of plant growth. the sourcesink manipulation treatments were imposed by removing the designated source organs with scissors after silking stage. leaf area was measured, at 7 days intervals throughout the growth period by an automatic leaf area meter immediately after leaf clipping. three plants were randomly collected from each unit plot and all the green leaves were taken for measuring leaf area by a leaf area meter (model amm-8, hayashi dehnko co. ltd., tokyo, japan). leaf area index was calculated by using the following formula collected been haveleaves thefrom where area ground leaves allof arealeaf of thesum lai = the data on yields and yield contributing characters of maize varieties and soil parameters were statistically analyzed by “mstatc” software to examine the significant variation of the results due to different treatments. the treatment means were compared by lsd at 5% level of significance. results and discussion cob length cob length varied significantly among the plant population grown at different densities and clipping levels (table 1). length of cob decreased significantly with the increasing level of population density. the plants grown at the lower density (66667 plants ha-1) produced the longest cob (154.7 mm) where leaf blades were removed below the lower most cobs. however, no significant reduction was recorded in cob length in other clipping treatment in same density. in contrast, the lowest cob length (119.3 mm) was 61 sourch-sink manipulation and population density of hybrid maize found in plants grown at 1,11,111 plants ha-1 and removed the tassel and all leaf blades below the lowermost cob. similar finding was reported by osorio (1976), loesch et al. (1976) and rathore et al. (1976). cob diameter the data pertaining to cob diameter as influenced by plant density, levels of defoliation and their interactions are presented in table 1. significant differences in cob diameter were noticed due to plant density and levels of defoliation. maximum cob diameter (46.36 mm) was recorded in treatments where all leaf blades below the lowermost cob were removed with 66,667 plants ha-1. however, minimum cob diameter (39.04 mm) was recorded in 1,11,111 plants ha-1 where tassel and all leaf blades below the lowermost cob were removed. number of grains per cob significant variations were observed in number of grains per cob in all plant densities and clipping levels (table 1). however, increasing level of clipping decreased the number of grains per cob. a gradual reduction in number of grains per cob with increasing the level of clipping was observed. among the treatments, the highest number of grains per cob (406) was recorded at the density of 66,667 plants ha-1 with no clipping (c1). however, no significant difference in grain numbers was found in other clipping treatments except 66667 plants ha-1. on the other hand, the lowest grains per cob were found in 1,11,111 plants ha-1with removal of all leaf blades except those adjacent to cob. statistically similar result was also found in removal of tassel and all leaf blades below the lower most cobs. in 83,333 plants ha-1, clipping treatments gave statistically similar result except removal of all leaf blades except those adjacent to cob which gave lower grains per cob than other clipping treatments. similar finding was reported by rathore et al. (1976). 100-grain weight 100 grain weight of maize was subjective to different density levels (table 1). however, increasing level of clipping decreased the 100-grain weight, even, within same density level. a gradual reduction in 100grain weight per treatment with the increasing level of clipping was also observed among the plant densities. it was recorded that tested hybrid maize produced the highest 100-grain weight (28.79 g) in 83333 plants ha-1 with no clipping (d2c1). however, the lowest 100-grain weight (24.49 g) was found in same density with removal of all leaf blades except those adjacent to cob. grain yield grain yield is the product of number of plant ha-1, cobs plant-1, grains cob-1 and individual grain weight. clipping treatment, at all density levels, there was a large impact on grain yield of maize (table 1) revealed that the grain yield significantly increased with the increasing level of density and decreased due to clipping. grain yield increased up to 7.9 t ha-1 in 1,11,111 plants ha-1 with no clipping (d3c1) and thereafter decreased with the interaction in density and clipping levels. except 1,11,111 plants ha-1 with no clipping and those three, all treatment was statistically similar. only 83333 plants ha-1 with removal of all leaf blades except those adjacent to cob, 1,11,111 plants ha-1 with removal of all leaf blades except those adjacent to cob and 66667 plants ha-1 with removal of all leaf blades except those adjacent to cob produced less than 5.21 t ha-1 grain where all other treatments produced more than 5.9 t ha-1 grain yield with a central tendency of 6.5 t ha-1 grain yield. furthermore, the yield increment was mainly owing to improvement in yield attributing characters at higher leaf present. in 1,111,11 plants ha-1 with no clipping, lai was significantly highest and the number of plant as well as cob ha-1 showed same result. increased grain yield under increasing level of leaf present might have increased in photosynthetic capacity due to increase in photosynthetic leaf surface, chlorophyll content, leaf longevity and partitioning of more accumulated dry mass from source to sink, favorable growth and nutrient uptake resulted hence produced higher grain yield. plants grew healthy and produced long size of cobs with bold 62 emran et al. and heavy grains in 66667 plants ha-1density. the results of present study can be favorably compared with those of hassen (2003), zewdu (2003), li-xiangjun et al. (2005) and chaudhary et al. (2005). narayanaswamy et al. (1994) and simeonov and tsankova (1990) also reported similar result. in contrast, vivas et al. (1988) reported that plant density was not a critical factor in determining maize yield. table 1. yield attributes of three population densities grown under four different clipping levels treatment combination cob length (mm) cob diameter (mm) grains cob-1 (no.) 100-grain weight (g) grain yield (t ha-1) harvest index (%) d1c1 152.5 45.91 406.0 28.56 6.572 45.75 d1c2 154.7 46.36 401.2 27.90 6.232 54.18 d1c3 148.9 45.89 371.5 27.70 5.927 51.50 d1c4 141.1 43.67 304.3 25.46 4.238 39.66 d2c1 141.6 43.99 331.2 28.79 6.486 44.17 d2c2 135.1 42.98 302.9 27.48 6.149 50.79 d2c3 134.8 44.48 308.5 28.05 6.323 59.14 d2c4 132.1 42.58 280.3 24.49 4.695 44.73 d3c1 131.3 43.30 314.3 28.41 7.906 48.06 d3c2 123.3 40.25 272.1 27.13 6.478 51.06 d3c3 119.3 39.04 213.9 25.90 6.536 52.03 d3c4 120.9 39.66 195.6 26.45 5.206 48.97 lsd(0.05) 11.13 2.314 45.37 1.604 0.9473 8.288 cv (%) 4.82 3.16 8.69 3.48 9.23 9.95 d1 = (75 cm x 20 cm ), 66667 plants ha-1 c1 = control (no clipping was done) d2 = (60 cm x 20 cm ), 83333 plants ha-1 c2 = removal of all leaf blades below the lowermost cob d3 = (60 cm x 15 cm ), 111111 plants ha-1 c3 = removal of tassel and all leaf blades below the lowermost cob c4 = removal of all leaf blades except those adjacent to cob the price of maize grain and fodder: tk. kg-1 12.50 and 2.5 harvest index the ratio of economic yield to biological yield is termed as harvest index. the highest harvest index (59.14%) was found in 83,333 plants ha-1 with removal of tassel and all leaf blades below the lower most cob treatment (table 2). the lowest hi (39.66%) was recorded in 66667 plants ha-1 with removal of all leaf blades except those adjacent to cob treatment with no clipping, 83333 plants ha-1. correlation analysis relationship between plant density and dependent variables correlation analysis evinces that cob length (r = -0.82), cob diameter (r = -0.745), number of grain per cob (r = -0.74), grain weight per cob (r = -0.67), total dry matter content (r = -0.69), light transmission rate before clipping (r = -0.685) had negative and significant (1%) relationship with crop density but none of the parameters exhibits significant positive relationship with crop density (table 2). this may be due to the struggle created by plant density. closer planting creates competition for nutrients and all other growth factors. grain yield showed affirmative but insignificant relationship with plant density might be that the number of cob increases with number of plant. the finding is consistent with the findings of osorio (1976), rathore et al. (1976), hsu and huang (1984) and loesch et al. (1976). relationship between leaf clipping and dependent variables 63 sourch-sink manipulation and population density of hybrid maize the computed pearson’s product moment correlation co-efficient at 5% level of probability implies that number of grain per cob (r = -0.48), grain weight per cob (r = -0.55), 100-grain weight (r = -0.71), grain yield (r = -0.71), total dry matter production (r = -0.67) and leaf area index (r = -0.91) maintained negative significant relationship with leaf clipping (table 2). the results confirms with the results of previous findings of zelitch (1982), chaudhary et al. (2005) and hassen (2003). the reason behind such type of relationship might be due to the fact that leaf clipping increases light transmission ratio and total photosynthetic activity may be reduced. on the other hand light transmission rate after clipping (r = 0.8) maintained positive significant relationship with leaf clipping. table 2. relationship between plant components with different treatment variables as influenced by leaf clipping and plant density cob length cob diameter no. of grain cob-1 grain wt. cob-1 100 grain wt. grain yield fodder yield total dry matter leaf area index light transmission ratio density -.823** -.745** -.742** -.674** -.116 .300 .243 -.686** .161 -.075 clipping -.305 -.306 -.482** -.549** -.710** -.713** .905** -.672** -.905** .805** cob length 1 .901** .897** .883** .387* .177 -.479** .787** .148 -.167 cob diameter 1 .869** .844** .421* .240 -.512** .735** .168 -.203 no.of grain cob-1 1 .907** .397* .297 -.643** .843** .311 -.353* grain wt. cob-1 1 .584** .485** -.703** .879** .401* -.532** 100 grain wt. 1 .588** -.696** .611** .645** -.687** grain yield 1 -.654** .322 .723** -.753** fodder yield 1 -.799** -.866** .773** total dry matter 1 .581** -.495** leaf area index 1 -.702** light transmission ratio 1 *indicates significant at 5% level ;**indicates significant at 1% level economic analysis the highest gross return and benefit cost ratio (bcr) was obtained from the treatment having 1,11,111 plants ha-1 with no clipping (tk. 98819 ha-1, bcr 1.78) while the lowest from the treatment with removal of all leaf blades except those adjacent to cob in 66,667 plants ha-1 (tk. 63604 ha-1, bcr 1.22) (table 3). in case of dual purpose,1,11,111 plants ha-1 with removal of tassel and all leaf blades below the lowermost cob gave the highest gross return (tk. 89520 ha-1) but 66667 plants ha-1 with removal of all leaf blades below the lowermost cob gave the highest bcr (1.6). table 3. yield and return of maize var.bari hybridmaize-7 production in three population densities grown under four different clipping levels treatment combination cost (tk.) fodder yield (t ha-1) grain yield (t ha-1) return from fodder (tk*) return from grain (tk.) gross return (tk.) bcr d1c1 50387 0.00 6.57 0.00 82147 82147 1.63 d1c2 51657 1.905 6.23 4763 77894 82657 1.6 d1c3 52005 1.905 5.93 4763 74086 78849 1.52 d1c4 52145 4.250 4.24 10627 52978 63605 1.22 d2c1 52434 0.00 6.49 0.00 81080 81080 1.55 d2c2 53755 2.397 6.15 5992 76862 82854 1.54 64 emran et al. d2c3 54342 2.397 6.32 5992 79033 85025 1.56 d2c4 54501 4.627 4.69 11567 58686 70253 1.29 d3c1 55489 0.00 7.91 0.00 98820 98820 1.78 d3c2 56338 3.127 6.48 7817 80976 88793 1.57 d3c3 56867 3.127 6.54 7817 81704 89521 1.57 d3c4 57265 6.258 5.21 15644 65080 80724 1.41 lsd(0.05) 0.9473 11840 0.2 cv (%) 9.23 8.53 7.87 d1 = (75 cm x 20 cm), 66667 plants ha-1 c1 = control (no clipping was done) d2 = (60 cm x 20 cm), 83333 plants ha-1 c2 = removal of all leaf blades below the lowermost cob d3 = (60 cm x 15 cm), 111111 plants ha-1 c3= removal of tassel and all leaf blades below the lowermost cob c4 = removal of all leaf blades except those adjacent to cob *75tk = 1 usd (approximately) conclusion grain yield increased up to 20% if no clipping was done with 1,11,111 plants ha-1, however, with the same density and removal of all leaf blades produced the highest fodder yield. the highest grain yield loss (35.5 %) was observed in 66,667 plants ha-1 with removal of all leaf blades, except those adjacent to cob. the highest gross return and bcr was obtained from 1,11,111 plants ha-1 with no clipping (tk. 98820 ha-1 and 1.78) and the lowest from 66667 plants ha-1 with removal of all leaf blades except those are adjacent to cob (tk. 63605 ha-1 and 1.22). in case of both grain and fodder yield, the combination of 1,11,111 plants ha-1 with removal of tassel and all leaf blades below the lowermost cob gave the highest gross return (tk. 89521 ha-1) but 66,667 plants ha-1 with removal of all leaf blades below the lowermost cob gave the highest bcr (1.6). references ahmad, n. and f. c. muhammad. 1999. plant density effect on yield and quality of maize seed. j. agric. res. 37 (1): 25-29. barthakur, b. c., s. nath and p. k. purkayastha. 1975. effect of dates of sowing, rates of nitrogen and planting densities on grain yield of hybrid maize ganga 11. indian j. agron. 20(3): 257-259. burton, w. j. 2004. effects of defoliation on seed protein concentration in normal and high protein lines of soybean. crop sci. 72: 131139. chaudhary, a. n., m. i. latif, haroon, m. ur-rasheed and g. jilani. 2005, profitability increase in maize production through fertilizer management and defoliation under rain fed cropping. int. j. of bio.and biotech., 2(4): 1007-1012. desiderio, e., l. cuocolo, g. mariani and m. monotti. 1989. effects of sowing date and plant density on yields of maize of different maturity groups. (in italian). informatore-agrario. 45(14): 57-69. egile, d. b. 2000. variation in leaf starch and sink limitations during seed filling in soybean. crop sci. 39: 1361-1368. hassen, h. 2003. effect of defoliation on yield components of maize and under sown forage. agri. topica, 18(1/2): 5-7. 65 sourch-sink manipulation and population density of hybrid maize hsu, a. n. and s.c. huang. 1984. effects of plant density on yield and agronomic characteristics of maize in spring and autumn cropping seasons. bull. taichung district agril. improv. sta. pub. no. 9. pp.13-21. kolcar, f. and z. videnovic. 1988. effect of time of planting and plant density on the grain yield of some zp hybrid of maize fao maturity group 200. arhiv-za-poljopri-vredne-nauke (yugoslavia) 49 (176): 309-320. li-xiangjun, s. anpinginanaga, a. e. enejj and a. m. ali. 2005. mechanisms promoting recovery from defoliation in determinate and indeterminate soybean cultivar. j. food agric. env.3(3/4):178-183. loesch, p. j. j., c.f. stark and m. s. zuber. 1976. effects of plant density on the quality of cobs used for corn cob pipes. crop sci. 16(5): 706-709. madhavan, m. v., s. shanmuegasundaram and s. p. palaniappar. 1986. effect of population on physiological growth parameters of pigeon pea genotypes in sole and inter cropped stand with sorghum co. 22. j. agron. crop sci. 157(1): 43-61. mostert, a. j. and j. n. marais. 1982. the effect of detasselling on the yield of irrigated maize. crop prod. 11: 163-167. mrityunjoy, b., i. m. ahmed, m. asaduzzaman and w. sultana. 2008. performance of intercropping grain maize with triticale and grasspea as forage crops. intl. j. sustain. crop prod. 3(6): 34-37. narayanaswamy, m. r., v. veerabadran, c. joyanthi and c. chinnuswammy. 1994. plant density and nutrient management for rainfed maize in red soil. madras agril. j. 81(5): 248-251. osorio, f.o. 1976. population effects on yield and other characteristics of maize in the e-1 zamorano valley, honduras. field crop abst. 33(2): 126-1980. rathore, d. m., k. singh and b. p. singh. 1976. effect of nitrogen and plant population on the yield attributes of maize. indian j. agric. res. 10(2): 79-82. sabir, m. r., s. a. h. shah, m. a. shahzad and i. ahmed. 2001. effect of plant population on yield and yield components of maize. j. agric. res. 39(2): 125-129. sawhney, j. s., s. s. bhinder, m. s. sidhu and r. s. narang. 1989. agronomic practices for higher productivity in winter maize. indian j. agron. 34(1): 24-26. simenov, n. and g. tsankova. 1990. effect of fertilizers and plant density on yield of maize hybrids with two years. (in bularian). rasteniev’dni-nauki 27(8): 14-18. sufian, m. a. and m. z. abedin. 1985. effect of plant population and plants per hill on the growth and yield of sweet corn. bangladesh j. agri. 10(2): 17-22. tano, f., m. r. mannino and f. aiello. 1987. row spacing and plant density of grain maize (part two). (in italian). informatore-agrario. 43(26): 59-61. vasic, g., krzic. and d. budimirovic. 1988. effect of late planting on maize yield under irrigation. savremenapoljoprivreda (yugoslavia) 36(11-12): 506-516. vivas, h., r. moresco and s. gambaudo. 1988. effects of nitrogen and plant density on maize production in eastern argentina. turrialba 38(2): 127-131. wang, o. q. 1996. effects of altered source sink ratio on canopy photosynthetic rate and yield of maize. photosynthetica. 32: 271-267. wipo. 2006. improved grain quality through altered expression of seed proteins. pub. no.: wo/2006/071219. http://www.wipo.int/pctdb/en/ zelitch, i. 1982. the close relation between net photosynthesis and crop yield. bio-sci. 32: 796-802. zewdu, t. 2003. effect of defoliation and intercropping with forage legumes on maize yield and forage production. trop. sci. 43(4): 204-207. http://www.wipo.int/pctdb/en/ 66 emran et al. microsoft word 8. baj-228_revised.docx bangladesh agron. j. 2016, 19(1): 59-66 yield of inbred and hybrid rice as affected by clonal tillers of successive generation p. k. hore1*, p. k. biswas1, a. k. m. r. amin1, raziuddin2, m. s. mahmud3 s. m. mohsin4 1 department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2scientific officer, regional agricultural research station, bari, rahamatpur, barishal, bangladesh 3research associate, collection, evaluation and introduction of white maize for human consumption in bangladesh, sher-e-bangla agricultural university, dhaka, bangladesh 4department of plant pathology, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author: shuvosau@gmail.com key words: yield, clonal tillers, rice key words: inbred, hybrid, clonal tillers, yield abstract a field experiment was conducted at the agronomy field, sher-e-bangla agricultural university, dhaka from november 2012 to july 2013. experiment consisted of two factors, viz. (i) varietybrri dhan29 (v1) and brri hybrid dhan2 (v2), and (ii) planting materialsnursery seedlings (n), first generation clonal tillers (c1) collected from n, second generation clonal tillers (c2) collected from c1, third generation clonal tillers (c3) collected from c2 and fourth generation clonal tillers (c4) collected from c3, following split-plot design with three replications. results revealed that despite higher (161.29) number of filled grains as obtained from brri dhan29 while lower (139.31) from brri hybrid dhan2, and maximum weight of 1000-grains (26.50 g) from hybrid variety and the minimum from the inbred one (19.70 g), the grain yield was not varied significantly. among the planting materials nursery seedlings gave the maximum (9.23 t ha-1) grain yield that followed by first generation clonal tillers (7.44 t ha-1), and second generation clonal tillers (6.57 t ha-1). the third and fourth generation clonal tillers also produced around 3 t ha-1 grain yield. the maximum grain yield (9.6 t ha-1) was observed from the combination of nursery seedlings with brri hybrid dhan2 which is statistically similar to the combination of same planting material with brri dhan29 (8.86 t ha-1). the first and second generation clonal tillers of both the varieties produced more than 6.0 t ha-1 grain yield. therefore, clonal tillers can be used as planting materials for both hybrid and inbred rice cultivation in case of scarce supply of nursery seedlings. introduction bangladesh is the fourth highest rice (oryza sativa l.) producing country in the world (fao, 2013). about 76.71% of the total cropped area was planted with rice in 2012-13. total rice production in bangladesh was about 10.59 million tons in 1971 when the country’s population was only about 70.88 million. however, the country is now producing about 34.00 million tons to feed her 149.69 million people (mondal and choudhury, 2014). rice yield therefore, needs to be increased from the present 2.74 to 3.74 t ha-1 (brri, 2011) but there is a little scope to increase rice area. moreover, the arable land is decreasing at the rate of 1% per annum (bbs, 2011). in such situation, there is no other alternative rather than development and adoption of yield enhancing technologies. to get higher productivity, hybrid rice is an important option which contribute 20-30% yield advantage over inbred varieties (julfiquar et al., 2009). hossain et al. (2003) reported that hybrid rice has the potentiality to increase 15-20% yield but it costs about 19% higher compared to inbred rice of which seed cost is the prime issue. among different groups of rice, boro season covers 60 hore et al. about 43.57% of total rice area which contributes 61.33% of the total rice production (bbs, 2008), but this rice production is affected by various biotic and abiotic constraints. damage of seedling in the seedbed due to cold has been identified as a constraint. in this perspective separation of tillers from rice plants could escape cold damage and replanting of the separated tillers to the new rice fields may be vital alternatives for growing boro rice (mamun et al., 2012). the detached tillers can be used as seedling, especially during scarcity of seedlings after flood or any other natural hazards (biswas, 2001). it is possible to transplant the separated tillers in the prepared main field those have the potentiality to produce yield as main crop (debnath, 2010). beside this, use of rice clonal tillers might be an option for maximum yield and reduce seed cost especially hybrid rice (debnath, 2010). as hybrid rice seeds are costly and scarce, successful use of their clonal tillers can help to reduce seed cost as well as expansion of hybrid rice cultivation area in bangladesh. on the other hand, the potentiality of inbred clonal tillers is reported by many researchers (biswas, 2001; biswas and saloke, 2001; parveen et al., 2008; hossain et al., 2011; sarkar et al., 2011; alim and sheuly, 2012). therefore, the present study with an inbred and a hybrid variety of boro rice was undertaken to compare the yield performance of the crop grown from their inbred and hybrid clonal tillers of successive generation and nursery seedlings. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka-1207 during the period from december 2012 to july 2013. the experimental area was situated at 2377n latitude and 9033e longitude at an altitude of 8.6 meter above sea level (anon., 2004) belongs to the agro-ecological zone of “the modhupur tract”, aez-28 (anon., 1988). the experiment was comprised of variety (v1 = brri dhan29 and v2 = brri hybrid dhan2) and planting materials (n= nursery seedlings, c1 = first generation clonal tillers collected from, c2 = second generation clonal tillers collected from c1, c3 = third generation clonal tillers collected from c2 and c4 = fourth generation clonal tillers collected from c3 ). the experiment was laid in a split-plot design with three replications having variety in the main plots and planting materials in the sub-plots. the size of unit plot was 5.0 m by 2.0 m. seeds were sown on the seedbed on november 12, 2013 for raising nursery seedlings. 33 days old nursery seedlings were uprooted carefully on december 15, 2012 and were kept in soft mud in shade. the seedlings were then transplanted with 25 cm × 15 cm spacing on the well-puddled plots. two sub-plots in each main plot was transplanted with nursery seedlings of which the entire hills of one plot was uprooted and splitted for using as first generation clonal tilletrs. the separated tillers were then re-transplanted as per treatment having one clonal tiller per hill on 30 january, 2013. second generation (c2) clonal tillers were separated from c1 plants at 30 dat and the separated tillers were then re-transplanted as per treatment having one clonal tiller hill-1 on 2 march, 2013. third generation (c3) clonal tillers were separated from c2 plants as earlier at 25 dat and the separated tillers were then re-transplanted as per treatment having one clonal tiller per hill on 27 march, 2013. lastly the fourth generation (c4) clonal tillers were separated from c3 plants at 20 dat and the separated tillers were then re-transplanted as per treatment having one clonal tiller hill-1 on 17 april, 2013. before re-transplanting, the individual plots were spaded properly for well puddle and an extra dose of urea (one third of basal) was top dressed after seven days of re-transplanting on uprooted plots and entire basal dose for newly transplanted plots. maturity of crop was determined when 90% of the grains become golden yellow in color. the harvesting of brri dhan29 was done on may 12; jun 3; jun 14; jul 1, 2013 for nursery seedlings (n) and first generation clonal tiller (c1); second generation clonal tiller (c2); third generation clonal tiller (c3) and fourth generation 61 yield of inbred and hybrid rice as affected by clonal tillers of successive generation clonal tiller (c4), respectively and the harvesting of brri hybrid dhan2 was done on may 4; may 21; jun 14; jul 1, 2013 for nursery seedlings (n) and first generation clonal tiller (c1); second generation clonal tiller (c2); third generation clonal tiller (c3) and fourth generation clonal tiller (c4), respectively. the grains were cleaned and sun dried to moisture content of about 12%. straw was also sun dried properly. finally grain and straw yields plot-1 were recorded and converted to t ha-1. all the data collected on different parameters were statistically analyzed and the mean differences were adjudged by least significant difference (lsd) test at 5 % level of significance (gomez and gomez, 1984). results and discussion effect of variety among yield contributing characters related to grain yield. panicle length, filled and unfilled grains panicle-1, and weight of 1000-grain were significantly influenced by the variety (table 1). the highest (26.79 cm) and lowest (22.77 cm) panicle length were obtained from brri dhan29 and brri hybrid dhan2, respectively. ahmed (2010) also observed maximum panicle length in brri dhan29 than hybrid variety and debnath (2012) found the highest panicle length in brri dhan29 and lowest in brri hybrid dhan2 among other varieties. the number of filled grains panicle-1 differed significantly for variation of the variety. higher number of filled grains panicle-1 (161.29) was found from inbred variety brri dhan29 and lower number of filled grains panicle-1 (139.31) from brri hybrid dhan2. higher number of unfilled grains panicle-1 (51.53) was found from inbred variety brri dhan29 and lower number of unfilled grains panicle-1 (8.52) from brri hybrid dhan2. this finding similar with debnath (2010) who found the highest number of unfilled grains panicle-1 from the inbred variety brri dhan29 than hybrid variety brri hybrid dhan2 though obaidullah (2007) observed the highest number of unfilled grains panicle-1 in the hybrid variety and the lowest in the inbred variety. the maximum (26.50 g) weight of 1000-grains was obtained from brri hybrid dhan2 and the minimum (19.70 g) weight from brri dhan29. the result supports the findings of obaidullah (2007), ashrafuzzaman (2006) and debnath (2010) who found the highest weight of 1000-grains in hybrid variety than the inbred variety brri dhan29. table 1. effect of variety on yield and other crop characters related to yield of two rice varieties treatments effective tillers (no. m-2) ineffective tillers (no. m-2) panicle length (cm) filled grains panicle-1 (no.) unfilled grains panicle-1 (no.) 1000grains weight (g) grain yield (t ha1) straw yield (t ha-1) harvest index (%) v1 234.27 24.99 26.79a 161.29a 51.53a 19.70b 6.05 5.59 52.26 v2 218.59 18.66 22.77b 139.31b 8.52b 26.50a 6.01 5.5 51.48 lsd (0.05) ns ns 0.591 7.978 15.150 0.486 ns ns ns cv (%) 23.87 52.98 1.54 3.38 32.11 1.34 5.08 7.80 4.27 v1 = brri dhan29, v2 = brri hybrid dhan2 effect of planting material yield and other characters such as ineffective tillers m-2, panicle length, filled and unfilled grains panicle-1, and weight of 1000-grains were significantly influenced by the planting 62 hore et al. material (table 2). the maximum (33.44) ineffective tillers m-2 was obtained from c1 which was statistically similar with nursery seedlings n (30.80) and the lowest (12.32) number in c4 which was statistically similar with c3 (15.84) and c2 (16.72). debnath (2012) also observed highest ineffective tillers m-2 in nursery seedlings compared to clonal tillers though ahmed (2010) found higher ineffective tillers m-2 in clonal tillers compared to nursery seedlings. the maximum (25.72 cm) panicle length was observed from c1 which was statistically similar with c2 (25.67 cm) and nursery seedlings (24.88 cm), and the lowest (23.72 cm) from c4 which was statistically similar with c3 (23.92 cm) and nursery seedlings (24.88 cm). paul (1999) and rahman (2001) found that nursery seedlings gave the longest panicles compared to the clonally propagated tillers. the maximum (171.60) number of filled grains panicle-1 was observed in c1 which was statistically similar with c2 (168.60) and the lowest (128.20) number in c4 which was statistically similar with c3 (139.80). the maximum (42.65) number of unfilled grains panicle-1 was observed in c1 which was statistically similar with c4 (37.83) and the lowest (19.75) number from c3 which was statistically similar with c2 (21.60) and nursery seedlings (28.30). the maximum 1000-grains weight (24.62 g) was obtained from c1 which was statistically similar with nursery seedlings (24.40 g) and the lowest (21.60 g) from c4 which was statistically similar with c3 (22.37 g). the highest (9.23 t ha-1) grain yield was obtained from the nursery seedlings (n) and the lowest (2.97 t ha-1) in c3. the yield reduction of clonal tillers than nursery seedlings was 19.39, 28.82, 67.827 and 57.62% for c1, c2, c3 and c4, respectively. the reduction of yield in clonal tillers compared to nursery seedlings might be due to the removal of tillers from the mother plant (murthy et al., 1991). the highest (8.27 t ha-1) straw yield was obtained from the nursery seedlings (n) and the lowest (2.82 t ha-1) in c3. debnath (2012), obaidullah (2007) and ahmed (2007) also found higher grain and straw yield in nursery seedlings than clonal tillers of first generation. table 2. effect of planting material on yield and other crop characters related to yield of two rice varieties treatments effectiv e tillers (no. m2) ineffective tillers (no. m-2) panicle length (cm) filled grains panicle-1 (no.) unfilled grains panicle-1 (no.) 1000grains weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) n 224.4 30.80a 24.88b 143.30b 28.30bc 24.40a 9.23a 8.26a 52.73 c1 237.6 33.44a 25.72a 171.60a 42.65a 24.62a 7.44b 6.87b 52.06 c2 214.7 16.72b 25.67a 168.60a 21.60c 22.53b 6.57c 6.07c 52.03 c3 208.6 15.84b 23.92b 139.80bc 19.75c 22.37bc 2.97e 2.82e 51.34 c4 246.9 12.32b 23.72b 128.20c 37.83ab 21.60c 3.91d 3.69d 51.20 lsd (0.05) ns 12.370 1.216 14.258 12.617 0.780 0.59 0.63 ns cv (%) 20.28 46.33 4.01 7.75 34.33 2.75 8.09 9.27 5.44 n = nursery seedlings, c1 = first generation clonal tillers collected from n, c2 = second generation clonal tillers collected from c1, c3 = third generation clonal tillers collected from c2, c4 =fourth generation clonal tillers collected from c3, ns = not significant interaction effect of variety and planting material yield and all other crop characters related to yield was significantly influenced by the interaction effect of variety and planting material (table 3). the maximum number of effective tillers m-2 (260.5) was observed in c1 of the inbred variety (v1) which was statistically similar with c2 (253.4), n (241.1) c4 (231.5), and c3 (184.8) of the inbred variety 63 yield of inbred and hybrid rice as affected by clonal tillers of successive generation (v1) and c3 (232.3), c1 (214.7) and n (207.7) of the hybrid variety (v2). lower number of effective tillers m-2 (176.0) was obtained from c2 of the hybrid variety (v2) which was statistically similar with c3 (184.8), c4 (231.5), n (241.1), c2 (253.4) and of the inbred variety (v1) and c3 (232.3), c1 (214.7) and n (207.7) of the hybrid variety (v2). debnath (2012) also observed combination of clonal tiller with brri dhan29 produce more effective tillers m-2 than combination with nursery seedlings of the same variety. the maximum (44.00) number of ineffective tillers m-2 was observed in nursery seedlings of the inbred variety (v1) which was statistically similar with c1 (33.44) of the same variety and c1 (33.40) of the hybrid variety (v2). the lowest number (8.80) of ineffective tillers m-2 was obtained from c4 of the hybrid variety (v2) which was statistically similar with c2 (12.30), c4 (15.84), and c3 (19.36) of the inbred variety (v1) and c3 (12.32), n (17.6) and c2 (21.12) of the hybrid variety (v2). debnath (2010) also found the highest ineffective tillers m-2 in combination of nursery seedlings with brri hybrid dhan2. the highest (25.72 cm) panicle length was observed in c4 (28.57 cm) of the inbred variety (v1) and the lowest ((18.87 cm) in c4 of the hybrid variety (v2). table 3. interaction effect of variety and planting material on yield and other crop characters of two rice varieties treatment s effective tillers (no. m-2) ineffective tillers (no. m-2) panicle length (cm) filled grains panicle-1 (no.) unfilled grains panicle-1 (no.) 1000grains weight (g) grain yield (t ha-1) straw yield (t ha1) harvest index (%) v1n 241.1ab 44.00a 26.20bc 139.7c 47.67bc 21.13c 8.86a 8.38a 51.46ab v1c1 260.5a 33.44ab 26.67b 166.6ab 77.00a 21.19c 7.23b 7.04b 50.76ab v1c2 253.4ab 12.32c 26.47bc 170.4a 36.90c 19.07d 6.22c 5.44c 53.22ab v1c3 184.8ab 19.36bc 26.03bc 145.7c 31.23c 19.20d 3.39e 2.94e 53.77ab v1c4 231.5ab 15.84c 28.57a 184.0a 64.87ab 17.89e 4.55d 4.16d 52.10ab v2n 207.7ab 17.60bc 23.57d 146.8bc 8.933d 27.66a 9.60a 8.18a 54.00a v2c1 214.7ab 33.44ab 24.77cd 176.6a 8.300d 28.05a 7.67b 6.71b 53.36ab v2c2 176.0b 21.12bc 24.87cd 166.8ab 6.300d 25.98b 6.94c 6.72b 50.83ab v2c3 232.3ab 12.32c 21.80e 133.9c 8.267d 25.53b 2.57e 2.70e 48.90b v2c4 262.2a 8.80c 18.87f 72.43d 10.80d 25.30b 3.28e 3.22e 50.31ab lsd (0.05) 79.5 17.5 1.72 20.17 17.84 1.1 0.8444 0.891 4.88 cv (%) 20.28 46.33 4.01 7.75 34.33 2.75 8.09 9.27 5.44 v1 = brri dhan29, v2 = brri hybrid dhan2 , n = nursery seedlings, c1 = first generation clonal tillers collected from n, c2 = second generation clonal tillers collected from c1, c3 = third generation clonal tillers collected from c2, c4 =fourth generation clonal tillers collected from c3 the maximum (184.90) number of filled grains panicle-1 was observed in c4 of the inbred variety (v1) which was statistically similar with c2 (170.40) and with c1 (166.60) of the inbred variety (v1) while lowest (72.43) from c4 of the hybrid variety (v2). higher (77.00) number of unfilled grains panicle-1 was observed in c1 of the inbred variety (v1) which was statistically similar with c4 (64.87) of the inbred variety (v1). the lowest (6.30) number of unfilled grains panicle-1 was obtained from c2 of the hybrid variety (v2) which was statistically similar with c3 (8.26), c1 (8.30), n (8.93) and c4 (10.80) of the hybrid variety (v2). debnath (2010) also observed similar result. the maximum 1000-grains 928.05g) was obtained from c1 of the hybrid variety (v2) which was statistically similar with nursery seedlings (27.66 g) of the hybrid variety (v2) and the lowest ((17.89 g)) from c4 of the inbred variety (v1). among the treatments, the maximum (9.60 t ha-1) grain yield was observed in nursery seedlings of the 64 hore et al. hybrid variety (v2), which was statistically similar with nursery seedlings (8.86 t ha-1) of the inbred variety (v1). the lowest (2.57 t ha-1) grain yield was observed in c3 of the hybrid variety (v2) which was statistically similar with c4 (3.28 t ha-1) of the same variety (v2), and with c3 (3.39 t ha-1) of the inbred variety (v1). higher straw yield (8.36 t ha-1) was observed in nursery seedlings (n) of the inbred variety (v1), which was statistically similar with nursery seedlings (8.18 t ha-1) of the hybrid variety (v2). the lowest straw (2.70 t ha-1) yield was observed in c3 of the hybrid variety (v2) which was statistically similar with c3 (2.94 t ha-1) of the inbred variety (v1) and c4 (3.22 t ha-1) of the hybrid variety (v2). conclusion the results of the experiment revealed that the yield of rice was identical between the inbred variety brri dhan29 and hybrid variety brri hybrid dhan2 though the crop grown from nursery seedlings produced the highest yield over that from the clonal tillers of successive generations. the highest grain yield and harvest index (9.60 t ha-1 and 54.00%, respectively) were observed from nursery seedlings of brri hybrid dhan2 and the lowest from third generation clonal tillers of brri hybrid dhan2 (2.57 t ha-1 and 48.90%, respectively). so the clonal tillers can be used up to second generation with little sacrifice of yield irrespective of inbred and hybrid rice. references ahmed, q. n. and p. k. biswas. 2010. different cultivation methods of paddy: new scopes for bangladesh, a comparative study of different cultivation methods on inbred and hybrid rice. vdm verlag dr. muller aktiengesellschaft & co. kg, dudweiler landstr. 99, 66123 saarbrucken, germany. ahmed, q. n., p. k. biswas and m. h. ali. 2007. influence of cultivation methods on the yield of inbred and hybrid rice. bangladesh j. agric. 32(2): 65-70. alim, m. a. and m. s. sheuly. 2012. effect of time of tiller separation on grain growth and seed yield of transplant aman rice. j. sci. found. 10(1): 12-19. anonymous. 1988. the year book of production. fao, rome, italy. anonymous. 2004. annual internal review for 2000-2001. effect of seedling throwing on the grain yield of wart land rice compared to other planting methods. crop soil water management program, agron. division, brri, gazipur. ashrafuzzaman, m. 2006. influence of tiller separation days on yield and yield attributes of inbred and hybrid rice. m.s. thesis. dept. of agron., sau, dhaka. babiker, f. s. h. 1986. the effect of zinc sulphate levels on rice growth and productivity. alexandria j. agril. res. 31(2): 480-481. bari, s. m. w. 2004. effect of method of planting and weeding on the yield and yield contributing characters of aman rice cv. brri dhan 32. m. s. thesis. dept. of agron., bau, mymensingh. bbs (bangladesh bureau of statistics). 2008. statistical yearbook of bangladesh for 2008. bbs (bangladesh bureau of statistics). 2011. statistical yearbook of bangladesh for 2011. 65 yield of inbred and hybrid rice as affected by clonal tillers of successive generation biswas, p. k. 2001. tiller dynamics and yield of parent and clonal plant of transplanted rice. doctoral dissertation. school of environment, resources and development, ait, thailand. biswas, p. k., and v. m. salokhe. 2001. effects of planting date, intensity of tiller separation and plant density on the yield of transplanted rice. j. agril. sci. camb. 137(3): 279-287. brri, 2011. bangladesh rice knowledge bank. internet edition. http://www.knowledgebankbrri.org/riceinban.php. accessed in december, 2011. debnath, a. 2010. influence of planting material and variety on yield of boro rice. m.s. thesis. dept. of agron., sau, dhaka. debnath, a., p. k. biswas, m. s. a. sardar and a. rahman. 2012. influence of mother and clonal tillers on yield and performance of inbred and hybrid boro rice. bangladesh agron. j. 15(1): 1-7. donald, c. m. 1963. competition among crops and pasture plants. adv. agron. 15: 11-18. fao (food and agriculture organization). 2013. fao statistics. internet edition. http://faostat.fao.org/site/339/default.aspx. accessed in october, 2013. gardner, f. p., r. b. pearce and r. l. mistechell. 1985. physiology of crop plants. iowa state univ. press, powa. p. 66. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. 2nd edn. intl. rice res. inst., john wiley and sons. new york. pp. 1-340. hossain, m. a., m. a. r. sarkar and s. k. paul. 2011. growth analysis of late transplant aman rice (cv. br23) raised from tiller seedlings. libyan agric. res. cen. j. intl. 2(6): 265-273. hossain, m., a. janaiah and m. husain. 2003. hybrid rice in bangladesh-farm level performance. economic and political weekly, june 21. irri. 2013. internet edition. http://irri.org/our-impact/increase-food-security. accessed in august, 2013. julfiquar, a. w., s. s. virmani., m. m. haque., m. a. mazid and m. m. kamal. 2009. hybrid rice in bangladesh: opportunities and challenges. rice research for food security and poverty allevation. proc. int. rice research conference. main, m. a. 2006. influence of planting material and planting methods on yield and yield attributes of inbred and hybrid rice. m.s. thesis. dept. of agron., sau, dhaka. mamun, m. a. a., r. shultana., b. c. roy., m. m. rana., a. parvez and a. j. mridha. 2012. effect of transplanting with separated tillers and planting time on the performance of boro rice. bangladesh agron. j. 15(2): 83-88. mondal, m. r. i. and d. a. choudhury. 2014. agronomic visions for sustainable food security. keynote paper presented at the 13th biennial conference of the bangladesh society of agronomy. pp. 26-29. murthy, p. s. s., p. j. r. reddy and s. s. r. prasad. 1991. effect of grain yield of shoot removal at different stage of aman rice crop growth. intl. rice res. newsl. 16(3): 10. obaidullah, m. 2007. influence of clonal tiller age on growth and yield of aman rice varieties. m.s. thesis. dept. of agron., sau, dhaka. parveen, s., m. p. anwar., s. m. a. hossain., l. h. abru and t. yeasmin. 2008. yield ability of tillers separated from t. aman rice cv. brri dhan41. j. agrofor. environ. 2(2): 171-175. 66 hore et al. paul, s. k. 1999. effect of row management and tiller separation on the growth and yield of transplant aman rice. m.s. thesis. dept. of agron., bau, mymensingh, bangladesh. rahman, m. s. 2001. effect of tiller plantation on the performance of transplant aman rice. m.s. thesis. dept. of agron., bau, mymensingh, bangladesh. sarkar, m. a. r., m. a. hossain and s. k. paul. 2011. effect of row arrangement, age of tiller seedling and number of tiller seedlings per hill on performance of transplant aman rice. j. agric. sci. 6(2): 59-68. bangladesh agron. j. 2016, 19(2): 95-103 residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops assessed by bioassay technique taslima zahan1*, md. moshiur rahman2 and mahfuza begum2 1bangladesh agricultural research institute, gazipur, bangladesh 2bangladesh agricultural university, mymensingh, bangladesh *corresponding author: taslimazahan_tzp@yahoo.com key words: herbicide, herbicide residue, rice, unpuddled transplanting abstract the residual effect of eight herbicides (pendimethalin, pyrazosulfuron-ethyl, butachlor, pretilachlor, orthosulfamuron, acetochlor + bensulfuron methyl, butachlor + propanil and 2,4-d amine) was applied in unpuddled transplanted aman rice in aa weedy and a hand weeded controls, was evaluated for succeeding crops viz. wheat, lentil and sunflower by following bioassay technique. a study was conducted at bangladesh agricultural university, mymensingh from november 2013 to january 2014 after harvest of unpuddled transplanted aman rice. all herbicides were imposed as weed management practice of unpuddled transplanted aman rice during july to august 2013. the experiment was laid out in a randomized complete block design (rcbd) with three replications. as a consequence, the residual effect of those herbicides on the succeeding wheat, lentil and sunflower crops was evaluated in term of germination, leaf chlorophyll content, seedling shoot length and dry matter. the results showed that seedling germination of all these succeeding crops in the herbicide treated plots did not differ significantly from those of weedy and hand weeded control plots. moreover, leaf chlorophyll content, seedling shoot length and dry matter of wheat, lentil and sunflower were not adversely affected by any of the herbicide treatments imposed in aman rice. it was concluded that herbicides used in unpuddled transplanted aman rice had no residual effect on the germination and leaf chlorophyll content, seedling shoot length and dry matter of the succeeding wheat, lentil and sunflower crops. introduction increasing labor crisis and high wage of labor encourages farmers to use herbicides for weed control in rice. several researches demonstrated that some herbicides can be accumulated in soil (machado-neto and victoria-filho, 1995; heeney et al., 1981) and some herbicides may not be accumulated but their residues might be present in the soil (tworkoski et al., 2000). if residue of herbicide may persist in the soil, the vigor of the non-target species and the succeeding crops can be reduced (houge and neilsen, 1988). wyk and reinhardt (2001) found excessive amount of imazethapyr residue caused injury to corn grown after soybean. moreover, janki et al. (2015) and hernandez-sevillano (2001) reported that few sulfonylurea herbicide residues in soil can affect rotational crops even at low concentrations. but, farmers usually use herbicides without knowing or testing the residual effect of herbicides on the succeeding crops. moreover no research has been done in bangladesh on the residual effect of herbicides on the succeeding crops. generally, a soil chemical test or bioassay can be used to determine the presence of herbicides in the soil (hager and nordby, 2007). however, chemical analysis is costly, and therefore a bioassay can be conducted to predict the presence of herbicides in soil which will be more feasible. although a bioassay does not measure the amount of herbicide residue present in the soil, but it 96 zahan et al. may indicate whether or not enough residue is present in soil to injure a sensitive succeeding crop. the bioassay can be carried out in pot trial by collecting the soil from the herbicide applied field or by in-situ trial in the micro-plots which is more convenient and more representative to express the residual effect of herbicides in the field situation. therefore, a bioassay study had conducted in the field after harvesting of unpuddled transplanted aman rice to evaluate the residual effect of rice herbicides on the succeeding crops. materials and methods the study was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh from november 2013 to march 2014. the experimental site is located at 24°75/ n latitude and 90°50/ e longitude in the south-west part of old brahmaputra under the agro-ecological zone old brahmaputra floodplain (aez-9) belonging to non-calcareous dark grey floodplain soil. the experimental field was a well drained medium high land with sandy clay loam soil texture (sand-50.0%, silt23.4% and clay-26.6%) having a ph of 6.8. the climate of the experimental area was under the subtropical region and characterized by high temperature, high relative humidity and heavy rainfall with occasional gusty winds during the kharif season (april to september) and scanty rainfall associated with moderately low temperature during rabi season (october to april). weather information regarding monthly average maximum and minimum air temperature and monthly total rainfall prevailed at the experimental site during the study period is presented in fig. 1. fig.1. monthly average maximum and minimum air temperature and total rainfall of the experimental site during june 2013 to may 2014 (source: weather yard, department of irrigation and water management, bau, mymensingh) the study was conducted by following bioassay method to evaluate the residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops, such as wheat, lentil and sunflower. each of these crops was sown in the same plots after harvesting of unpuddled transplanted aman rice. in unpuddled transplanted aman rice, 4 pre-emergence herbicides, 1 early postand 3 post-emergence herbicides were applied in combinations of 18 herbicide treatments along with a weedy and a weed free control viz, t1=weedy control, t2= weed free (4 hand weeding), t3=pendimethalin followed by (fb) hand weeding (hw) at 25 days after transplanting (dat), t4=pyrazosulfuron-ethyl fb hw at 25 dat, t5=butachlor fb hw at 25 dat, t6=pretilachlor fb hw at 25 dat, t7=pendimethalin fb 0 5 10 15 20 25 30 35 40 jun e'1 3 jul y'1 3 aug ust '13 sep tem ber'1 3 octo ber'1 3 nov em ber'1 3 dece mber '13 jan uary '13 feb rua ry' 13 marc h'1 3 apri l'13 may '13 a ir t em pe ra tu re (o c ) 0 50 100 150 200 250 300 350 t ot al r ai nf al l ( m m ) max. temp. min. temp. rainfall 97 residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops (acetochlor + bensulfuron methyl), t8=pyrazosulfuronethyl fb (acetochlor + bensulfuron methyl), t9=butachlor fb (acetochlor + bensulfuron methyl), t10=pretilachlor fb (acetochlor + bensulfuron methyl), t11 =pendimethalin fb orthosulfamuron fb (butachlor + propanil), t12=pyrazosulfuron-ethyl fb orthosulfamuron fb (butachlor + propanil), t13=butachlor fb orthosulfamuron fb (butachlor + propanil), t14=pretilachlor fb orthosulfamuron fb (butachlor+propanil), t15= pendimethalin fb orthosulfamuron fb 2,4-d amine, t16=pyrazosulfuron-ethyl fb orthosulfamuron fb 2,4-d amine, t17=butachlor fb orthosulfamuron fb 2,4-d amine and t18= pretilachlor fb orthosulfamuron fb 2,4-d amine. the experiment was set up in a randomized complete block design (rcbd) with three replications. unit plot size was 3 m x 4 m. all herbicides were applied in unpuddled transplanted aman rice at their recommended rate (table 1) from 25 july to 16 august 2013 (pendimethalin, pyrazosulfuron-ethyl, pretilachlor and butachlor were applied at 3 days after rice transplanting (dat), orthosulfamuron at 15 dat, acetochlor + bensulfuron methyl, butachlor+propanil and 2,4-d amine at 25 dat). table 1. application rate of herbicides and name of their chemical group which were applied in unpuddled transplanted aman rice during 2013 name of herbicide chemical group of herbicide rate of application pendimethalin dinitroaniline 2.50 l ha-1 pyrazosulfuron-ethyl sulfonylurea 150 g ha-1 butachlor chloroacetamide 25 kg ha-1 pretilachlor chloroacetamide 1.0 l ha-1 orthosulfamuron sulfonylurea 150 g ha-1 (acetochlor+bensulfuron methyl) chloroacetamide+sulfonylurea 0.74 kg ha-1 (butachlor+propanil) chloroacetamide+amide 1.0 l ha-1 2,4-d amine phenoxy-carboxylic-acid 2.25 l ha-1 aman rice was harvested on 04 november 2013 and after harvesting, pre-planting knockdown herbicide glyphosate @ 2.25 l ha-1 was applied on 16 november 2013 to kill the existing weeds of the field. then wheat, lentil and sunflower were grown in 1m x 1m micro-plots within each of the main plots on 26 november 2013. before seeding, micro-plots were prepared through required number of spading and other earth work and then the land was fertilized by phosphorus, potassium and sulphur @ 32, 25, 17 kg ha-1, respectively in the form of triple super phosphate, muriate of potash and gypsum, respectively. nitrogen fertilizer was applied @ 46 kg ha-1 into two installments at 0 and 15 days after sowing of wheat, lentil and sunflower in the form of urea. 100 seeds of wheat (var. bari gom-26), lentil (var. barimasur-6) and sunflower (var. bari surjomukhi-2) were sown in each of the micro-plots by dibbling. the crop was monitored frequently from date of sowing and data were collected from each of the micro-plots up to 25 days after sowing (das). germination of the three crops was counted from 5 das to 25 das. seedling shoot length was measured from the base (ground level) of the randomly selected five plants to the tip of the longest leaf. these plants were uprooted and cleaned with distilled water; oven dried at 70o c for 48 hrs and then shoot dry matter was recorded. in case of leaf chlorophyll content, data were taken from two spots of the young, tender leaf of randomly selected five plants from each micro-plot by spad meter and the 98 zahan et al. average value was taken. the collected data were analyzed statistically and means were compared by dmrt using mstat-c. results and discussion germination percentage table 2 showed that herbicides used in unpuddled transplanted aman rice had no significant effect on germination of wheat, lentil and sunflower. previous studies also reported that germination of succeeding crops did not significantly affected by herbicides applied in onion (rathod et al., 2014) and in groundnut (vaghasia and nadiyadhara, 2013). in another study, khokhar and charak (2011) also reported that herbicides applied in wheat had no significant effect on germination of the three tested succeeding crops viz., maize, green gram and cucumber. the reason might be the complete degradation of those used herbicides in the soil or might be the presence of those herbicides below the detectable level that might not adversely affect the germination of the succeeding crops. several studies agreed that residues of most of the herbicides that were used in the present study persisted below of the detectable limit in the soil within 30-120 days after application (sireesha et al., 2012; naveen et al., 2012; dharumarajan et al., 2011). table 2. residual effect of herbicides used in unpuddled transplanted aman rice on germination of wheat, lentil and sunflower during 2013 treatments germination (%) wheat lentil sunflower t1= weedy 87 71 86 t2= weed free by hand weeding (hw) 90 73 92 t3= pendimethalin fb hw 92 74 90 t4= pyrazosulfuron-ethyl fb hw 90 76 88 t5= butachlor fb hw 93 70 92 t6= pretilachlor fb hw 91 70 87 t7= pendimethalin fb (acetochlor + bensulfuron methyl) 88 75 87 t8= pyrazosulfuron-ethyl fb (acetochlor + bensulfuron methyl) 89 77 88 t9= butachlor fb (acetochlor + bensulfuron methyl) 92 74 90 t10= pretilachlor fb (acetochlor + bensulfuron methyl) 89 73 86 t11= pendimethalin fb orthosulfamuron fb (butachlor + propanil) 87 71 84 t12= pyrazosulfuron-ethyl fb orthosulfamuron fb (butachlor + propanil) 91 75 83 t13= butachlor fb orthosulfamuron fb (butachlor + propanil) 89 72 86 t14= pretilachlor fb orthosulfamuron fb (butachlor + propanil) 86 73 90 t15= pendimethalin fb orthosulfamuron fb 2,4-d amine 86 72 85 t16= pyrazosulfuron-ethyl fb orthosulfamuron fb 2,4-d amine 91 74 89 t17= butachlor fb orthosulfamuron fb 2,4-d amine 93 71 94 t18= pretilachlor fb orthosulfamuron fb 2,4-d amine 92 71 89 level of significance ns ns ns 99 residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops cv (%) 3.79 6.76 4.82 ns = not significant, fb = followed by, hw = hand weeding, cv = co-efficient of variance leaf chlorophyll content (spad value) in case of spad values of leaves of wheat, lentil and sunflower at 25 days after sowing (das), no significant difference was found among herbicides applied in unpuddled transplanted aman rice (table 3). though no literature was found on effect of herbicide residue on leaf chlorophyll content of the succeeding crops, but so many reports are available that claimed that herbicide residue had no adverse effect on growth and yield of the succeeding crops (parthipan et al., 2013; sangeetha et al., 2012). despite the fact that the concentration of herbicide residue decrease exponentially with time and less than 1% of the initial concentration of herbicide applied in summer persist in the following winter (tworkoski et al., 2000), so there will be no chance to get affected the succeeding winter crops by herbicide residues of summer rice. table 3. residual effect of herbicides used in unpuddled transplanted aman rice on leaf chlorophyll content (spad value) of wheat, lentil and sunflower at 25 days after sowing during 2013 treatments spad value wheat lentil sunflower t1= weedy 42.50 21.07 31.27 t2= weed free by hand weeding (hw) 44.13 19.13 33.23 t3= pendimethalin fb hw 45.10 21.57 33.43 t4= pyrazosulfuron-ethyl fb hw 46.80 19.37 34.90 t5= butachlor fb hw 43.90 18.10 35.43 t6= pretilachlor fb hw 43.83 20.67 35.90 t7= pendimethalin fb (acetochlor + bensulfuron methyl) 46.07 23.93 33.47 t8= pyrazosulfuron-ethyl fb (acetochlor + bensulfuron methyl) 45.40 19.27 33.17 t9= butachlor fb (acetochlor + bensulfuron methyl) 45.80 22.37 32.97 t10= pretilachlor fb (acetochlor + bensulfuron methyl) 44.33 18.23 32.10 t11= pendimethalin fb orthosulfamuron fb (butachlor + propanil) 44.97 20.43 33.03 t12= pyrazosulfuron-ethyl fb orthosulfamuron fb (butachlor + propanil) 45.20 19.73 31.80 t13= butachlor fb orthosulfamuron fb (butachlor+propanil) 43.93 22.53 32.00 t14= pretilachlor fb orthosulfamuron fb (butachlor+propanil) 47.67 22.37 31.83 t15= pendimethalin fb orthosulfamuron fb 2,4-d amine 46.10 22.87 34.20 t16= pyrazosulfuron-ethyl fb orthosulfamuron fb 2,4d amine 44.47 23.43 33.80 t17= butachlor fb orthosulfamuron fb 2,4-d amine 44.00 24.50 35.67 t18= pretilachlor fb orthosulfamuron fb 2,4-d amine 45.43 22.80 32.57 level of significance ns ns ns cv (%) 4.53 11.13 5.74 100 zahan et al. ns = not significant, fb = followed by, hw = hand weeding, cv = co-efficient of variance shoot length (cm) table 4 demonstrated that herbicides applied in unpuddled transplanted aman rice had no significant effect on shoot length of wheat, lentil and sunflower at 25 das. this result is in agreement with sangeetha et al. (2012), bahrampor and ziveh (2013) and yadav et al. (2015) that no significant difference was found in shoot length of the succeeding crops with herbicides applied in the previous crop. but in some studies, plant height or dry or fresh weight was found to be sensitive to sulfonylurea herbicide (stork and hannah, 1996; vicari et al., 1994; junnila et al., 1994). table 4. residual effect of herbicides used in unpuddled transplanted aman rice on shoot length of wheat, lentil and sunflower at 25 days after sowing during 2013 treatments shoot length (cm) wheat lentil sunflower t1= weedy 88.1 6.41 16.0 t2= weed free by hand weeding (hw) 84.4 5.54 17.7 t3= pendimethalin fb hw 90.5 6.17 17.2 t4= pyrazosulfuron-ethyl fb hw 89.7 6.41 17.1 t5= butachlor fb hw 85.9 6.30 16.3 t6= pretilachlor fb hw 85.5 5.95 17.7 t7= pendimethalin fb (acetochlor+bensulfuron methyl) 90.1 6.52 16.3 t8= pyrazosulfuron-ethyl fb (acetochlor+bensulfuron methyl) 85.5 6.01 15.3 t9= butachlor fb (acetochlor+bensulfuron methyl) 87.9 6.34 16.7 t10= pretilachlor fb (acetochlor+bensulfuron methyl) 90.0 5.53 16.4 t11= pendimethalin fb orthosulfamuron fb (butachlor+propanil) 87.9 4.75 15.8 t12= pyrazosulfuron-ethyl fb orthosulfamuron fb (butachlor+propanil) 90.5 6.30 18.8 t13= butachlor fb orthosulfamuron fb (butachlor+propanil) 91.0 6.22 18.8 t14= pretilachlor fb orthosulfamuron fb (butachlor+propanil) 86.1 5.87 16.7 t15= pendimethalin fb orthosulfamuron fb 2,4-d amine 85.9 5.67 15.9 t16= pyrazosulfuron-ethyl fb orthosulfamuron fb 2,4-d amine 91.4 5.95 16.1 t17= butachlor fb orthosulfamuron fb 2,4-d amine 88.9 5.23 17.0 t18= pretilachlor fb orthosulfamuron fb 2,4-d amine 86.6 6.24 18.6 level of significance ns ns ns cv (%) 2.74 11.80 8.27 ns = not significant, fb = followed by, hw = hand weeding, cv = co-efficient of variance dry matter production the results demonstrated that dry matter productions (g m-2) of wheat and lentil were not significantly varied with herbicides applied in unpuddled transplanted aman rice. while dry matter of sunflower significantly differed with herbicides, but reduction in dry matter production of sunflower was not observed (table 5). therefore, results expressed that herbicides applied in rice had no adverse effect on the succeeding 101 residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops wheat, lentil and sunflower crops. similar result also reported by rathod et al. (2014) and bahrampor and ziveh (2013) that dry matter production of the succeeding crops was not adversely affected by herbicide residue. yadav and bhullar (2014) also found that herbicides applied in soybean had no significant effect on dry matter accumulation of the succeeding crops (wheat, barley, spinach, pea, raya, canola and sugarbeet) because of the complete degradation of herbicides used in the previous crops. table 5. residual effect of herbicides used in unpuddled transplanted aman rice on dry matter of wheat, lentil and sunflower at 25 days after sowing during 2013 treatments crop dry matter (g m-2) wheat lentil sunflower t1= weedy 9.40 2.76 21.58 ab t2= weed free 11.47 2.78 20.94 b t3= pendimethalin fb hw 9.71 2.58 24.22 ab t4= pyrazosulfuron-ethyl fb hw 12.15 3.28 26.61 a t5= butachlor fb hw 11.33 2.78 21.32 ab t6= pretilachlor fb hw 10.08 2.95 21.15 b t7= pendimethalin fb (acetochlor+bensulfuron methyl) 9.85 2.97 24.83 ab t8= pyrazosulfuron-ethyl fb (acetochlor + bensulfuron methyl) 11.36 2.77 24.38 ab t9= butachlor fb (acetochlor+bensulfuron methyl) 10.67 3.19 24.36 ab t10= pretilachlor fb (acetochlor+bensulfuron methyl) 10.12 2.87 21.06 b t11= pendimethalin fb orthosulfamuron fb (butachlor+propanil) 10.39 2.37 23.47 ab t12= pyrazosulfuron-ethyl fb orthosulfamuron fb (butachlor+propanil) 11.12 3.32 26.29 ab t13= butachlor fb orthosulfamuron fb (butachlor+propanil) 11.00 2.94 22.97 ab t14= pretilachlor fb orthosulfamuron fb (butachlor+propanil) 10.30 2.35 22.91 ab t15= pendimethalin fb orthosulfamuron fb 2,4-d amine 11.51 3.08 24.41 ab t16= pyrazosulfuron-ethyl fb orthosulfamuron fb 2,4-d amine 11.93 2.65 26.67 a t17= butachlor fb orthosulfamuron fb 2,4-d amine 11.75 2.77 26.10 ab t18= pretilachlor fb orthosulfamuron fb 2,4-d amine 9.72 3.87 24.01 ab level of significance ns ns * cv (%) 11.28 14.40 7.43 in a column, figures with similar letters are not significantly different (as per dmrt) ns = not significant, * = significant at 5% level of significance, fb = followed by, hw = hand weeding, cv = co-efficient of variance conclusion the results revealed that herbicides applied in unpuddled transplanted aman rice had no adverse effect on germination, leaf chlorophyll content, shoot length and dry matter of wheat, lentil and sunflower. therefore, the study concluded that herbicides 102 zahan et al. applied in unpuddled transplanted aman rice had no residual effect on the succeeding crops. however, it is strictly advised to apply herbicide at the recommended rate by following proper rules and regulations. acknowledgements this study was the part of the phd research of the senior author and the author would like to acknowledge aciar (project lwr/2010/080) for funding the research project and providing a scholarship by dr. richard w. bell, murdoch university. references bahrampor, t. and p. s. ziveh. 2013. effects of residue sulfonylurea herbicides on wheat. intl. j. agron. plant prod. 4(10): 2707-2713. dharumarajan, s., r. sankar and s. arun. 2011. persistence and dissipation of pretilachlor in soil, plant and water of coastal rice ecosystem. indian j. weed sci. 43(3&4): 199-202. hager, a. g. and d. nordby. 2007. herbicide persistence and how to test for reside in soil. in: illinois agricultural pest management handbook. pp. 343-350. heeney, h. b., v. warren and s. u. khan. 1981. effects of annual repeat applications of simazine, diuron, terbacil, and dichlorbenil in a mature apple orchard. canadian j. plant sci. 61: 325-329. hernandez-sevillano, e., m. villarroya, j. l. alonso-prados and j. m. garcia-baudin. 2001. bioassay to detect mon-37500 and triasulfuron residues in soil. weed technol. 15: 447-452. houge, e. j. and g. h. neilsen. 1988. effects of excessive annual applications of ternacil, diuron, simazine and dichlobenil on vigor, yield and cation nutrition of young apple trees. canadian j. plant sci. 68: 843-850. janki, p., n. sharma, c. chinnusamy, n. sakthivel and c. nithya. 2015. herbicide residues and their management strategies. indian j. weed sci. 47(3): 329-344. junnila, s., h. heinonen-tanski, l. r. ervi ő and p. laitinen. 1994. phytotoxic persistence and microbiological effects of chlorsulfuron and metsulfuron in finnish soils. weed res. 34: 431-423. khokhar, a. k. and a. s. charak. 2011. bio-efficacy of herbicides against complex weed flora in wheat and their residual effects on succeeding crops. j. crop weed. 7(2): 164-167. machado-neto, j. g. and r. victoria-filho. 1995. dissipation of herbicide residues in the soil of a citrus orchard (citrus sinensis l. osbeck) after the ninth consecutive annual application. bull. environ. cont. toxic. 55: 303-308. naveen, d. v., r. c. gowdaand and b. mamatha. 2012. field studies on persistence of pyrazosulfuron-ethyl in soil, ground water and residues in transplanted rice. asian j. soil sci. 7: 8-12. parthipan, t., v. ravi, e. subramania and t. ramesh. 2013. integrated weed management on growth and yield of transplanted rice and its residual effect on succeeding black gram. agron. j. 12(2): 99-103. rathod, a. d., r. m. solanki, j. m. modhavadia and d. r. padamani. 2014. efficacy of preand post-emergence herbicides in onion and their carry over effect on the succeeding crops. ann. agric. res. n. seri. 35(2): 209-216. sangeetha, c., c. chinnusamy and n. k. prabhakaran. 2012. efficacy of imazethapyr 103 residual effect of herbicides applied in unpuddled transplanted aman rice on the succeeding crops productivity of soybean and its residual effect on succeeding crops. indian j. weed sci. 44(2): 135-138. sireesha, a., p. c. rao, p. v. rao, g. swapna and c. s. ramalakshmi. 2012. residues of pendimethalin and oxyfluorfen in radish and their persistence in soil. j. crop weed. 8(2): 120-125. stork, p. and m. c. hannah. 1996. a bioassay method for formulation testing and residue studies of sulfonylurea herbicides. weed res. 36: 271-278. towrkoski, t. j., w. v. welker and g. d. vass. 2000. soil residues following repeat applications of diuron, simazine, and terbacil. weed technol. 14(1): 191-196. vaghasia, p. m. and m.v. nadiyadhara. 2013. effect of post-emergence herbicides in groundnut and its residual effect on succeeding crops. intl. j. fores. crop improve. 4(2): 54-58. vicari, a., p. catizone and r.l. zimdahl. 1994. persistence and movility of chlorsulfuron and metsulfuron under different soil and climatic conditions. weed res. 34: 147-155. wyk, l. j. v. and c. f. reinhadt. 2001. a bioassay technique detects imazethapyr leaching and liming-dependent activity. weed technol. 15: 1-6. yadav, p. p. i., e. k. syriac, t. george and s. mathew. 2015. studies on harvest time residue of pyrazosulfuron ethyl, a new generation herbicide, in transplanted rice in the entisol of vellayani, south kerala. intl. j. agric. sci. vet. med. 3(3): 49-54. yadav, r. and m. s. bhullar. 2014. residual effects of soybean herbicides on the succeeding winter crops. indian j. weed sci. 46(3): 305-307. bangladesh agron. j. 2014, 17(1): 11-22 effect of planting arrangements on productivity of cotton + mungbean intercropping systems m. f. a. i. tabib1, m. a. karim2, m. m. haque2, q. a. khaliq2 and a. r. m. solaiman2 1 deputy director, cotton development board, dhaka region, dhaka. 2 professor, bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur. corresponding author: tabibfai@gmail.com key words: spatial arrangement, cotton, mungbean, intercropping abstract an experiment was conducted at the cotton research farm, sreepur, gazipur during 2009-10 growing season to maximize the benefit of cotton + mungbean intercropping system through appropriate planting arrangement of component crops in the system. performance of eight different planting arrangements, such as 1, 2, 3 and 4 rows of mungbean in between single row of cotton and 4, 5, 6 and 7 rows of mungbean in between paired row cotton ware compared against their sole cropping. intercropping and mungbean density reduced individual yield of cotton and mungbean compared to their sole cropping but increased equivalent yield of both cotton and mungbean. the highest seed cotton (2951 kg ha-1) and mungbean (3373 kg ha-1) equivalent yield was recorded from the paired row cotton +4-row mungbean. the land equivalent ratio of the same combination indicated 31% yield advantage over sole cropping. the same plating arrangement also recorded the highest gross return (tk. 118039 ha-1), gross margin (tk. 60220 ha-1) and bcr (2.04). thus, the panting arrangement of paired row cotton and 4 rows of mungbean could be grown for higher productivity and economic return in the system. introduction cotton is an industrial crop as well as cash crop to the farmer’s in bangladesh. the area and production of cotton in the country are limited compared to its annual demand of 4.2 million bales in 2011 (anon., 2011; adams et al., 2011). to meet the demand vertical expansion is the appropriate option rather than horizontal one from the limited land resources of the country. intercropping is the proven option of vertical expansion of cotton that can help to ensure both subsistence and disposable income to the farmers (singh and jodha, 1990). long duration with initially slow growing cotton and short duration fast maturing mungbean appeared to be the most compatible companion crops in the intercropping system (rao, 1991) and also been proved to be productive and economic in the tropical countries (sayampol and changsalak, 1997). the overall productivity in terms of cotton equivalent yield was generally higher in intercropping system than that in sole stand (maitra et al., 2000).the productivity and efficiency of intercropping system depends, to a large extent, on the nature and extent of plant competition (harper, 1977) and the spatial arrangement and densities of the component crops (nataranjan, 1990). aasim et al. (2008) revealed that paired row cotton seemed well compared to single row cultivation for easy harvesting and handling of intercrop without any damage to the base crop cotton. mungbean (vigna radiata) is a short duration crop that matures at around 60-70 days, which could be fitted well in cotton + mungbean intercropping system. however, it is necessary to determine the optimum population of mungbean as a companion crop to minimize competition with the main cotton crop. this experiment was therefore, undertaken to determine the appropriate planting arrangement of both cotton and mungbean in order to achieve maximum productivity and economic return from cotton + mungbean intercropping system. materials and methods 12 tabib et al. the experiment was conducted at the cotton research farm, sreepur, gazipur during 2009-10 growing season. the site was high land and located in the centre of madhupur tract of agro-ecological zone (aez)-28. the soil of the experimental site belongs to the salna series and is classified as shallow redbrown terrace type which falls under the order inceptisols of soil taxonomy (anon., 1988; brammer, 1996). experiment was laid out in randomized complete block design (rcbd) with three replications. the unit plot size was 5.4 m x 4.5 m. eight different plating arrangements of cotton and mungbean were compared with paired row and single row sole cotton and sole mungbean. cotton population was 100% of sole cropping in all arrangements but mungbean population was 28, 44, 56, 67, 78, 83 and 111% of sole mungbean. cotton var. cb-10 and mungbean var. bumung-4 were used for the experiment. single row cotton + 1-row mungbean single row cotton + 2-row mungbean single row cotton + 3-row mungbean single row cotton + 4 -row mungbean paired row cotton + 4-row mungbean paired row cotton + 5-row mungbean paired row cotton + 6-row mungbean paired row cotton + 7-row mungbean legend: cotton mungbean fig. 1. sketch of the different spatial arrangements of cotton and mungbean all the treatments except sole mungbean was fertilized with 23-34-17.5-18-4.60-2.2-1.90 kg of n p k s zn b and mg ha-1, respectively as urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate, borax and magnesium sulphate. additional three top dressing of 23 kg n each and 22.5-30-17.5 kg k were applied at 20, 40 and 60 days after sowing (anon., 2009). sole mungbean was fertilized at the rate of 23-17-18 kg of n p k ha-1, respectively. liming was done 25 days before sowing by using dolochun camg (co3)2 at the rate of 2 tons ha-1 while 5 tons of cowdung ha-1 was incorporated with the soil at the time of final land preparation. both cotton and mungbean were sown on 21 july 2009. cotton and 13 productivity of cotton+mungbean intercropping systems mungbean seeds were soaked into water for 3 hours just before sowing. the mungbean seeds were treated with vitavex-200 at the rate of 3g kg-1 and cotton seed with gaucho at the rate of 5g kg-1. three seeds of cotton and 3-4 seeds of mungbean per hill were hand planted in dibbling method. cotton took 5-7 days and mungbean took 3-5 days to emergence. immediately after sowing light irrigation was given to ensure uniform crop emergence. subsequent irrigation was also provided to avoid any moisture stress. two times weeding, eight times insecticide spraying, two times hand picking of bollworm larvae were performed to keep the field free from pest. mature mungbean pods were harvested at 55 and 65 das and mature seed cotton in three installments at 150, 165 and 180 das. data on agronomic traits of cotton and qualitative characters of cotton including fibre length, fibre strength, micronaire and ginning out turn was also recorded. lint and seed yield was recorded after separation of seed and lint from seed cotton by using ‘lummus 20saw’ ginning machine. fibre length, fibre strength and micronaire were measured by using fibrograph instrument, pressly meter and micronaire testing instruments, respectively. data on yield and yield components of mungbean was measured at harvest from randomly selected plants. the productivity of cotton + mungbean intercropping system was assessed by land equivalent ratio (ler), monetary advantage index (mai) and equivalent yield of cotton and mungbean by using the standard formula as well as cost and benefit analysis was also calculated. the data were analyzed statistically and means were separated by least significance difference (lsd) test at 5% level of significance (gomez and gamez, 1984). the formula used for different parameters are given below. seed index = weight of 100-seed lint index = weight of lint x seed index weight of seed harvest index (hi%) = grain yield x 100 total biological yield gross return (tk. ha-1) = total yield (kg ha-1) × unit market price (tk. kg-1) gross margin (tk. ha-1) = gross returntotal variable cost ginning outturn (%) = weight of lint x 100 weight of seed cotton land equivalent ratio (ler) = intercrop yield of cotton + intercrop yield of mungbean sole crop yield of cotton sole crop yield of mungbean monetary advantage index (mai) = value of combined intercrop x (ler-1) ler seed cotton equivalent yield = intercrop yield of seed cotton (kg ha-1) + intercrop yield of mungbean (kg ha-1) × selling price of mungbean selling price of seed cotton (tk) mungbean equivalent yield = intercrop yield of mungbean (kg ha-1) + intercrop yield of seed cotton (kg ha-1) × selling price of seed cotton selling price of mungbean (tk) 14 tabib et al. benefit cost ratio (bcr) = gross return / total variable cost results and discussion yield components and seed cotton yield number of sympods and monopods plant-1 in cotton number of sympods and monopods plant-1 varied with the variation in spatial arrangement of cotton and mungbean in intercropping systems (table 1). cotton under single row sole cropping produced the highest number of sympods plant-1 (17.97) but lowest number of monopods plant-1 (0.73), which was significantly different from intercropping treatments. sympods plant-1 was decreased with increased in mungbean row number in between cotton rows and the lowest number of sympods plant-1 (8.67) was in single row cotton+4-row mungbean arrangement (t7). but monopods plant-1 was increased with the increasing competition between component crops under intercropping systems and the highest was observed in single row cotton + 4-row mungbean arrangement (t7). higher number of branches plant-1 in sole cotton was also reported by oad et al. (2007) under cotton + pigeaon pea intercropping system and mahatale et al. (2008) in cotton based intercropping system. number of bolls plant-1 and single boll weight in cotton cotton yield was determined by the number of bolls plant-1 and single boll weight, which was significantly differed by the spatial arrangements of cotton and mungbean under cotton + mungbean intercropping systems (table 1). cotton under single row sole cropping produced the highest number of bolls plant-1 (28.73) and single boll weight (6.24 g) compared to other intercropping treatments. the spatial arrangement of densely populated and closer spacing produced lower number of bolls plant-1 and single boll weight. the lowest number of bolls plant-1 (14.60) and single boll weight (5.00 g) was recorded from single row cotton + 4-row mungbean (t7). higher number of bolls plant-1 under sole cropping was also reported by oad et al. (2007) and reduced bolls weight from densely populated cotton was reported by junior et al. (2003). seed cotton yield seed cotton yield is considered as economic yield, which is the function of number of bolls palnt-1 and single boll weight although it was considerably influenced by the variations in spatial arrangements of cotton and mungbean under cotton + mungbean intercropping systems (table 1). the maximum seed cotton yield (2885 kg ha-1) was recorded in single row sole cotton (t1) followed by paired row sole cotton (t2). intercropping reduced the seed cotton yield by 2.43 to 30.16%. this yield reduction was occurred due to the competition for growth resources between component crops under intercropping systems. under intercropping conditions, the highest seed cotton yield was recorded from the treatment of paired row cotton + 4-row mungbean (t8) and the lowest (2015 kg ha-1) single row cotton + 4-row mungbean arrangement (t7). the reduction in seed cotton yield due to growing intercrops in association with cotton was also reported by sanjay et al. (2003), basavarajappa et al. (2003) and khan et al. (2001). table 1. seed yield and yield components of cotton as influenced by different planting arrangements of cotton and mungbean in intercropping systems treatments no. of sympods plant-1 no. of monopods plant-1 no. of bolls plant-1 single boll weight (g) seed cotton yield (kg ha-1) t1 17.97 0.733 28.73 6.237 2885 t2 16.87 0.900 25.27 6.187 2639 t4 16.33 1.267 23.50 5.940 2543 15 productivity of cotton+mungbean intercropping systems t5 15.43 1.533 20.70 5.800 2520 t6 10.07 2.133 18.33 5.163 2280 t7 8.667 2.500 14.60 5.000 2015 t8 16.43 1.267 23.83 6.047 2575 t9 15.50 1.433 23.07 5.917 2460 t10 12.97 1.667 20.65 5.560 2343 t11 11.20 1.967 19.20 5.467 2292 lsd (0.05) 1.07 0.23 1.77 0.196 132.80 cv (%) 4.40 8.59 4.73 2.01 3.16 t1=sole single row cotton, t2= sole paired row cotton, t4= single row cotton+1-row mungbean, t5= single row cotton+2-row mungbean, t6= single row cotton+3-row mungbean, t7= single row cotton+4-row mungbean, t8= paired row cotton+4-row mungbean, t9= paired row cotton+5-row mungbean, t10= paired row cotton+6-row mungbean, t11= paired row cotton+7-row mungbean. yield and yield components of mungbean number of pods plant-1, single pod weight, number of seeds pod-1 and 1000-seed weight is an important attribute of yield in grain legumes. these attributes are varied significantly with the variations in spatial arrangements of cotton and mungbean (table 2). mungbean under sole cropping (t3) recorded the highest number of pods plant-1 (26.27), single pod weight (0.70 g), number of seeds pod-1 (12.93) and 1000-seed weight (43.70 g). all the yield components were reduced with increasing mungbean density in closer spatial arrangements under intercropping systems. the lowest number of pods plant-1 (15.40), single pod weight (0.48 g), number of seeds pod-1 (10.43) and 1000-seed weight (34.88 g) was recorded from the treatment of single row cotton+4-row mungbean (t7). similar result of the highest number of pods plant-1, seeds pod-1 and 1000-seed weight from sole cropping compared to intercropped mungbean was reported by khan et al. (2012). harvest index in mungbean variations in spatial arrangements of cotton and mungbean in intercropping systems significantly affected the harvest index of mungbean (table 2). the highest harvest index (33.64%) was found in sole cropping while lowest harvest index (16.72%) was recorded from the single row cotton + 4-row mungbean (t7). bhatti et al. (2008) reported a higher harvest index in sole mungbean than the intercropped mungbean. seed yield seed yield in mungbean was found to be varied with the variations in spatial arrangements of cotton and mungbean in intercropping systems (table 2). sole cropping of mungbean showed superiority in seed yield (1322 kg ha-1), which was significantly different from other treatments due to the highest number of pods plant-1, single pod weight, seed pod-1, 1000-seed weight and plant population. under intercropping condition the highest seed yield was found in paired row cotton + 7-row mungbean (t11). crop competition in densely populated spatial arrangement reduces seed yield in mungbean and the lowest seed yield (301.7 kg ha-1) was recorded from the treatment of single row cotton + 1-row mungbean (t4). onuh et al. (2011) recorded the highest seed yield from the sole mungbean compared to the intercrop mungbean. table 2. seed yield and yield components of mungbean as influenced by different spatial planting arrangements of cotton and mungbean intercropping systems treatments no. of pods plant1 single pod weight (g) no. of seeds pod-1 1000-seed weight (g) harvest index (%) seed yield (kg ha-1 ) t3 26.27 0.700 12.93 43.70 33.64 1322.0 16 tabib et al. t4 23.60 0.583 12.37 41.28 21.87 301.7 t5 19.87 0.576 11.47 38.70 23.05 453.0 t6 16.80 0.503 11.23 35.85 20.13 566.0 t7 15.40 0.483 10.43 34.88 16.72 526.7 t8 23.67 0.620 12.47 41.36 29.55 441.0 t9 21.53 0.580 11.77 39.73 21.12 472.0 t10 19.07 0.556 11.40 38.51 20.17 519.0 t11 18.40 0.530 11.27 37.90 20.80 571.0 lsd (0.05) 2.05 0.017 0.59 1.92 3.66 76.21 cv (%) 5.78 3.76 2.92 2.84 9.18 7.66 t3= sole mungbean, t4= single row cotton+1-row mungbean, t5= single row cotton+2-row mungbean, t6= single row cotton+3row mungbean, t7= single row cotton+4-row mungbean, t8= paired row cotton+4-row mungbean, t9= paired row cotton+5-row mungbean, t10= paired row cotton+6-row mungbean, t11= paired row cotton+7-row mungbean. gin and fibre quality of cotton gin properties gin properties of cotton was determined by got, seed index and lint index and these properties were significantly varied with the variations in spatial arrangements of cotton and mungbean in intercropping systems (table 3). cotton under sole cropping showed better performance in got (38.07%), seed index (10.67g) and lint index (6.81g). the spatial arrangement of single row cotton + 4-row mungbean (t7) was found lowest got (30.12%), seed index (7.87g) and lint index (3.52g) of cotton. the reasons for that reduction may be due to the intercropping and spatial arrangements. fibre quality of cotton fibre length, strength and micronaire are the measure of fibre quality of cotton and which was significantly affected by the different spatial arrangements of cotton and mungbean in intercropping systems (table 3). cotton under sole cropping showed better in fibre length (2.81 cm), fibre strength (84.92) and micronaire value (4.53) compared to intercrop. the lowest fibre length (2.60 cm), poor strength and low micronaire were measured in cotton under single row cotton+4-row mungbean (t7). the result indicated that the increase in plant density, decreasing the fibre length, strength and micronaire in cotton. table 3. gin and fibre quality of cotton as influenced by different spatial arrangements of cotton and mungbean under intercropping systems treatments got (%) seed index (g) lint index (g) fibre length (cm) fibre strength (psi) micronaire value t1 38.07 10.67 6.810 2.81 84.92 4.533 t2 37.76 10.50 6.580 2.80 84.60 4.433 t4 35.11 10.11 5.680 2.72 83.69 4.400 t5 33.57 9.757 5.130 2.66 83.09 4.400 t6 31.98 8.407 4.063 2.62 82.78 4.100 t7 30.41 7.867 3.523 2.60 82.73 4.067 t8 36.24 10.15 6.053 2.73 84.23 4.433 t9 34.19 9.817 5.303 2.70 83.50 4.400 t10 30.12 9.607 4.297 2.65 82.92 4.367 17 productivity of cotton+mungbean intercropping systems t11 32.78 9.563 4.797 2.64 82.87 4.267 lsd(0.05) 2.86 0.597 0.80 0.15 1.86 0.31 cv% 4.91 3.61 8.94 3.39 1.30 4.90 t1=sole single row cotton, t2= sole paired row cotton, t4= single row cotton+1-row mungbean, t5= single row cotton+2-row mungbean, t6= single row cotton+3-row mungbean, t7= single row cotton+4-row mungbean, t8= paired row cotton+4-row mungbean, t9= paired row cotton+5-row mungbean, t10= paired row cotton+6-row mungbean, t11= paired row cotton+7-row mungbean assessment of intercrop productivity land equivalent ratio the land equivalent ratio (ler) is the main index of intercropping advantage and intercrop productivity. the ler varied significantly due to the variations in spatial arrangements of cotton and mungbean in intercropping systems (table 4). the highest ler (1.31) was recorded in paired row cotton + 4-row mungbean (t8) and the lowest (1.10) from single row cotton+4-row mungbean (t7). yield advantages in intercropping system over sole cropping was also reported by eskandari (2012), das et al. (2012) and islam et al. (2004). equivalent yield intercrop productivity was evaluated by the equivalent yield of the component crops. the highest seed cotton (2951 kg ha-1) and mungbean equivalent yield (3373 kg ha-1) was achieved from the treatment of paired row cotton + 4-row mungbean (t8) and the lowest seed cotton (2475 kg ha-1) and mungbean (2829 kg ha-1) from single row cotton + 4-row mungbean (t7). the result indicated a definite yield and intercropping advantage with paired row cotton+4-row mungbean in intercropping systems. islam et al. (2004) also found the highest maize equivalent yield from maize paired row plus four rows of bushbean combination in maize + bushbean intercropping system. higher equivalent yield under intercropping situation than that of sole crops was also reported by patel et al. (2010), das et al. (2012) and ali et al. (2007). monetary advantage index another productivity indices monetary advantage index (mai) significantly varied due to the variations in spatial arrangements of cotton and mungbean in intercropping systems (table 4). the highest mai (27670) was calculated from the treatment of paired row cotton + 4-row mungbean (t8) and the lowest mai (8931) was found in single row cotton + 4-row mungbean (t7). the result indicated that paired row cotton is advantageous over single row in intercropping situation and 4-row mungbean in between paired row cotton performed the best in terms of mai. aasim et al. (2008) also revealed that positive monetary index obtained from intercropping cotton with cowpea and sorghum. table 4. land equivalent ratio (ler), equivalent yield of cotton and mungbean and monetary advantage index (mai) as influenced by different spatial arrangements in intercropping systems treatments ler seed cotton equivalent yield kg ha-1 mungbean equivalent yield kg ha-1 mai t1 1.00 2885 3297 t2 1.00 2639 3016 t3 1.00 1156 1322 t4 1.11 2807 3208 11030 t5 1.22 2916 3333 20800 t6 1.22 2776 3172 20010 t7 1.10 2475 2829 8931 18 tabib et al. t8 1.31 2951 3373 27670 t9 1.29 2857 3265 25290 t10 1.28 2797 3197 24550 t11 1.30 2791 3190 25790 lsd(0.05) 0.05 145.40 166.20 5825 cv% 2.70 3.23 3.23 16.22 t4= single row cotton+1-row mungbean, t5= single row cotton+2-row mungbean, t6= single row cotton+3-row mungbean, t7= single row cotton+4-row mungbean, t8= paired row cotton+4-row mungbean, t9= paired row cotton+5-row mungbean, t10= paired row cotton+6-row mungbean, t11= paired row cotton+7-row mungbean. market price (tk kg-1): seed cotton-40/-, mungbean-35/ economic evaluation monetary advantages obtained from different spatial arrangements of cotton and mungbean in intercropping systems varied significantly (table 5). higher values of gross return (tk.118039 ha-1), gross margin (tk.60220 ha-1) and bcr (2.04) obtained from paired row cotton + 4-row mungbean (t8) than the sole cropping. under intercropping systems, single row cotton + 4-row mungbean (t7) showed lower values of gross return (tk. 88270 ha-1), gross margin (tk. 26930 ha-1) and bcr (1.44). the result of the present study was supported by the findings of sankaranarayanan et al. (2010) in cotton with vegetables and legumes and bhatt et al. (2010) in cotton + sesame intercropping system. higher economic returns from intercropping compared to monocropping was also reported by macuacua and santos (2007). table 5. total cost, gross return, gross margin and benefit cost ratio (bcr) as influenced by different spatial arrangements of cotton and mungbean in intercropping systems treatments total cost (tk. ha-1) gross return (tk. ha-1 ) gross margin (tk. ha-1) benefit cost ratio t1 59830 115407 55570 1.93 t2 57380 105576 48190 1.84 t3 26100 46258 20150 1.77 t4 59840 112277 52440 1.87 t5 60370 116655 56290 1.93 t6 60840 111022 50180 1.82 t7 61340 88270 26930 1.44 t8 57810 118039 60220 2.04 t9 58390 114269 55880 1.96 t10 58560 111889 53330 1.90 t11 58750 111652 52900 1.90 lsd (0.05) 502.2 11010 10930 0.1942 t1=sole single row cotton, t2= sole paired row cotton, t3= sole mungbean, t4= single row cotton+1-row mungbean, t5= single row cotton+2-row mungbean, t6= single row cotton+3-row mungbean, t7= single row cotton+4-row mungbean, t8= paired row cotton+4-row mungbean, t9= paired row cotton+5-row mungbean, t10= paired row cotton+6-row mungbean, t11= paired row cotton+7-row mungbean. market price (tk kg-1): seed cotton40/-, mungbean35/ conclusion 19 productivity of cotton+mungbean intercropping systems based on the results of the present experiment it was concluded that paired row cotton + 4-row mungbean was the best combination in relation to ler, equivalent yield, monetary advantage index, economic returns and benefit cost ratio. references adams, g., s. boyd and m. huffman. 2011. economic outlook for us cotton 2011. national cotton council of america. p.70. aasim, m., m. u. ejaz and a. karim. 2008. yield and competition indices of intercropping cotton (gossypium hirsutum l.) using different planting patterns. tarim bilimleri dergisi, 14: 326-333. ali, m. o., m. j. alam, m. s. alam, m. a. islam and m. shahin-uz-zaman. 2007. study on mixed cropping mungbean with sesame at different seeding rates. int. j. sustain. crop prod. 2: 74-77. anonymous. 2011. directors report, bangladesh textile mills association (btma), url: http://www.btmadhaka.com anonymous. 2009. tula utpadon kormosuchi. cotton development board. khamarbari, farmgate, dhaka. pp.45-50. anonymous.1988. land resources appraisal for agril. dev. rep. 2. agroecological regions of bangladesh, fao, rome. basavarajappa, r, a. s. prabhakar and s. i. halikatti. 2003. foxtail millet (setaria italica l.) based intercropping systems under shallow alfisols. karnataka j. agril sci. 16: 514-518. bhatt, b. k., s. k. dixit and v. b. darji. 2010. monetary evaluation of sesame based intercropping systems. indian j. agril. res. 44: 146-149. bhatti, i. h., r. ahmad, a. jabbar, z. a. virk and m. aslam. 2008. agro-economic performance of mungbean intercropped in sesame under different planting patterns. pak. j. agri. sci. 45: 25-28. brammer, h. 1996. the geography of soils of bangladesh, university pub. ltd., dhaka das, a. k., q. a. khaliq and m. l. haider. 2012. efficiency of wheat-lentil and wheat-chickpea intercropping systems at different planting configurations. int. j. sustain. crop prod. 7: 25-33. eskandari, h. 2012. yield and quality of forage produced in intercropping of maize (zea mays) with cowpea (vigna sinensis) and mungbean (vigna radiata) as double cropped. j. basic. appl. sci. res. 2: 93-97. gomez , k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. 2nd edn. john willey and sons. inc. new york. pp.304-307. harper, j. l. 1977. population biology of plants. academic press. new york. islam, m. n., m. m. haque and a. hamid. 2004. spatial arrangement and population density effects on productivity of maize-bushbean intercropping systems. bangladesh j. agril. res. 29: 467-474. junior, e. f., n. m. d. silva, l. h. carvalho, n. bortoletto, j. c. sabino and d. bolonhezi. 2003. types of growth regulator application, planting densities and nitrogen levels for the cotton cultivar iac 22. bragantia. 62: 227-233. khan, m. a., k. naveed, k. ali, b. ahmad and s. jan. 2012. impact of mungbean-maize intercropping on growth and yield of mungbean. pak. j. weed sci. res.18: 191-200. khan, m. b, m. akhtar and a. khaliq. 2001. effect of planting patterns and different intercropping systems on the productivity of cotton (gossypium hirsutum l.) under irrigated conditions of faisalabad. intl. j. agric. biol. 3: 432-435. 20 tabib et al. mahatale, p. v., u. v. mahadkar and y. v. manatale. 2008. studies on planting pattern, intercropping and fertilizer levels on growth and yield attributes of irrigated cotton (cv.phule-492). ann. plant physiol. 22: 192-195. macuacua, r. c. f. and l. santos. 2007. evaluation of a cotton-pigeon pea strip-intercropping system in morrumbala district (mozambique). 8th african crop science society conference, el-minia, egypt. 27-31-october-2007. pp.231-232. maitra, s., d. c. ghosh, g. sounda, p. k. jana and d. k. roy. 2000. productivity, competition and economics of intercropping legumes in finger millet (eleusine coracana) at different fertility levels. indian j. agric. sci. 70: 824–828. nataranjan, m. 1990. statistical analysis of intercropping experiments designed to address basic research issue. in: s. r. waddington, a. f. e. palmer, and o. t. edje (eds), proceedings of a workshop on research methods for cereal/legume intercropping in eastern and southern africa, 23-27 jan 1989, at lilongwe, malawi, pp.68-73. oad, f. c., m. h. siddiqui and u. a. buriro. 2007. agronomic and economic interference between cotton (gossypium hirsutum l.) and pigeon pea (cajanus cajan l.) j. agron. 6: 199-203. onuh, m. o., n. c. ohazurike and a. ijezie. 2011. effects of mungbean/melon/maize intercrop on the growth and yield of mungbean (vigna radiata (l.) wilczek) cultivated in owerri rainforest area. world j. agril sci. 7: 161-165. patel, j. g., m. h. patel, v. kumar and v. m. patel. 2010. possibilities of intercropping in g. cot. hy. 10 under irrigated condition. j. cotton res. dev. 24: 160-163. rao, v. p. 1991. a study on intercropping of cotton with grain legumes under rainfed conditions. j. res. , andra pradesh agric.univ. 19: 73-74. sankaranarayanan, k., c. s. praharaj, p. nalayini, k. k. bandyopadhyay and n. gopalakrishnan. 2010. legume as companion crop for cotton . j. cotton res. dev. 24: 115-126. sanjay, m. t., v. b. nadagouda, b. t. pujari, a. naranagouda and somshekar. 2003. intercropping in short duration compact cotton anjali. crop res. hisar. 26: 224-230. sayampol, n. and s. changsalak. 1997. add peanut to corn-cotton relay cropping system. kasetsart j. nat. sci. 31: 23-29. singh, r. p. and n. s. jodha. 1990. determinants of intercropping in the semi-arid tropics (progress report). economics group resource management program, icrisat, patancheru, andhra pradesh, india. report no. 95. p.14. 21 productivity of cotton+mungbean intercropping systems bangladesh agron. j. 2016, 19(2): 11-20 system productivity of potato + maize intercropping as affected by sowing date a.a.begum1, m.s.u.bhuiya2, s.m.a. hossain2, amina khatun3, s.k. das4and m.y. sarker5 1agronomy division, bari, 2 department of agronomy, bau, 3 rfs division, brri, 4bangladesh betar, dhaka and 5bjri, dhaka *corresponding author: luckyshamol6869@gmail.com key word: sowing date, shading, lai, dm, cgr, equivalent yield, potato, maize, intercropping abstract the experiment was conducted at agronomy research field, bangladesh agricultural research institute (bari), gazipur during 2009-2010 to find out suitable sowing time of maize in potato + maize intercropping for maximum yield and economic return. treatments of the experiment were: t1= simultaneous sowing (ss) of potato and hybrid maize (hm), t2= ss of potato and composite maize (cm), t3= hm sown 10 days after potato planting (dapp), t4= cm sown 10 dapp, t5= hm sown 20 dapp, t6= cm sown 20 dapp, t7= hm sown 30 dapp, t8= cm sown 30 dapp, t9= hm sown 40 dapp, t10 = cm sown 40 dapp, t11= sole potato, t12= sole hm and t13= sole cm. the result revealed that sole potato and maize produced the highest yield, lai, tdm and cgr. the hm showed better performance than cm. the highest equivalent yield and monetary return indicated that potato + hm sown 30 dapp intercropping was the most productive and profitable. introduction intercropping is an important tool for getting higher productivity per unit area of land and it improves the food security (mahfuza et al., 2012). intercropping system becomes productive and economical only when it is done properly by selecting compatible crops (begum et al., 2010), by shifting the period of peak demand for growth resources through changing the time of sowing of the component crops (santalla et al., 1999) and when their component crops differ in photosynthetic pathway, growth habit, growth duration and demand for growth resources (islam et al., 2007). potato and maize may be grown as intercrop as they have different photosynthetic pathway, growth habit, growth duration and demand for growth resources. potato is now becoming an important food for ensuring food security in bangladesh. conversely, maize (zea mays l.) is the third most important food grain for human after rice and wheat. maize in bangladesh is becoming an important crop in the rice-based cropping pattern. in recent years maize is gaining popularity among the farmers mainly due to high yield, more economic return and versatile uses. sowing of component crops in different times is an important agronomic approach in intercropping systems but has not been extensively studied. intercropping of 20-35 days after the planting of potato can bring very high profit, providing 20-21 t ha-1 maize equivalent yield within five months (cimmyt office in bangladesh, 2006). however, information relating sowing time of potato and maize in an intercropping system is very scarce. so, to understand the nature and extent of competition and complementarities of component crops, the experiment was undertaken to find out suitable sowing date of maize in potato maize intercropping for getting higher yield and economic return. mailto:luckyshamol6869@gmail.com 12 begum et al. materials and methods the experiment was conducted at the agronomy research field of bari, gazipur during the rabi season of 2009-2010. the soil of the experimental field was chhiata clay loam having ph 6.49, organic matter 1.08%, total n 0.034(%), potassium 0.18 meq/100g soil, phosphorus 13.5 ppm, sulphur 14.5 ppm, zinc 1.13 ppm and boron 0.21 ppm. maximum and minimum temperatures ranged from 24.11 to 35.13 and 11.21 to 25.450c, respectively, during the study period. average monthly rainfall for this period was 45.00 mm where maximum rainfall was recorded 228.00 mm and minimum 8.00 mm. thirteen treatments were as follows: t1= simultaneous sowing (ss) of potato and hybrid maize (hm), t2= ss of potato and composite maize (cm), t3= hm sown 10 days after potato planting (dapp), t4= cm sown 10 dapp, t5= hm sown 20 dapp, t6= cm sown 20 dapp, t7= hm sown 30 dapp, t8= cm sown 30 dapp, t9= hm sown 40 dapp, t10= cm sown 40 dapp, t11= sole potato, t12= sole hm and t13= sole cm. the experiment was laid out in randomized complete block design with three replications. the size of a unit plot was 6.0 m  5.0 m. potato var. bari alu-8 (cardinal) and maize var. bari hybrid maize-7 and bari maize-7 (composite) were used in the experiment. potato was planted on 20 november 2009. sole potato and sole maize were also planted on the same date. potato was planted with 60 cm × 25 cm spacing in sole and 75 cm  20 cm spacing in intercrop situation. maize was sown in 75 cm  20 cm spacing both in sole and intercrop situation. in intercrop treatments, one row of maize accommodated in between two rows of potato. for sole potato, sole hybrid maize and sole composite maize fertilizers were applied @ n180p40k180s20zn6b1.2, n260p72k148s48zn4b2 and n160p50k100s40zn4b2 kg/ha, respectively (barc, 2005). for intercrop fertilizers were applied @ n320p73k170s50zn6b2 kg/ha (akhteruzzaman et al., 2008). the source of n, p, k, s, zn and b was urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate and boric acid, respectively. in case of sole potato, half amount of urea, mop and the whole amount of tsp, gypsum, zinc sulphate and boric acid were applied at the time of final land preparation. remaining amount of urea and mop were applied at 30 days after planting (dap). for sole maize, one-third of urea and whole amount of other fertilizers were applied at the time of final land preparation. remaining amount of urea was applied in two equal splits as side dressing at 30 and 55 days after sowing (das). in case of intercrop, onethird (1/3) urea and of all other fertilizers were applied as basal. onethird urea and rest of all other fertilizers were side dressed at 30 dap of potato and rest of urea was side dressed just after potato harvest followed by irrigation. four irrigations were given during the cropping period. first irrigation was given after potato planting, second at 30 dapp, third at 55 dapp and lastly at 95 dapp (just after potato harvest). fungicide (dithane m-45) was sprayed at every 10-day intervals beginning from 25 to 70 dap for preventing potato disease. shading (%) was computed by converting photo synthetically active radiation (par) and measured by par ceptometer (model – lp-80, accu par, decagon, usa) at 60, 68, 76, 84 and 92 dapp at around 11:30 a.m. to 13:00 p.m. par was calculated using the following equation and expressed in percentage (ahmed et al., 2010): 100 incpar partincpar int(%)par    where, par int = intercepted par, par inc = incident par and part = transmitted par shading (%) on underneath crop, par int (%) by upper storied crop 13 system productivity of potato + maize intercropping as affected by sowing date plants were sampled at 15 day intervals from 30 days to maturity for potato and 20 day intervals from 30 to 130 days after sowing for maize and green leaf area was measured by an automatic leaf area meter (model: li-300, usa). plant materials were oven dried at 700c to a constant weight and dry weight taken. crop growth rate of the component crops was computed by using the following equation (gardner et al., 1985): crop growth rate (cgr) = (w2-w1) / (t2-t1) where, w = weight of dry matter unit-1 area and t = time (days) and the subscripts 1 and 2 indicate measurements at time t1 and t2, respectively. potato was harvested on 24 february 2010 (95 dap) and maize was harvested at 132-146 das. yield of both crops were taken from whole plot. potato equivalent yield was computed by converting yield of intercrops on the basis of prevailing market price of individual crop following the formula of bandyopadhyay (1984) as given below: potato equivalent yield = yip + (yim  pm) / pp where, yip = yield of intercrop potato, yim = yield of intercrop maize, pp = market price of potato and pm = market price of maize. collected data of both the crops were analyzed statistically and the means were adjudged using dmrt. economic analysis was also done considering local market price of harvested crops. results and discussion plant shading (%) shading given by maize plants on underneath potato crops over time differed significantly at all the time intervals (fig. 1). shading increased progressively up to potato harvest. the highest shading (80%) was observed in t1 (simultaneous sowing) at 90 dap (days after planting) and the lowest shading in t9 (52%) followed by t10 (when maize sown 40 dapp), t7 & t8 (maize sown 30 dapp). similar trend was observed at all the intervals. shading (2070%) was occurred by maize canopy on underneath potato crop during tuber bulking period (40-80 dap) when maize was sown simultaneous with potato and 10 or 20 dap of potato. on the other hand, 040 % shading given by maize canopy during tuber bulking period (40-80 dap) when maize was sown 30 and 40 dapp and tuber bulking could start before shading given by maize plant and the degree of shading from 40 dap onward was not exceed over 40 % and more than 60 % of the total incoming solar radiation transmitting through the maize canopy which was sufficient for continued rapid tuber bulking. the result revealed that planting date of maize intercropped with potato, maize sown on 30 days after planting of potato is suitable for intercropping. maize grain yield was drastically reduced might be due to hot temperature at later growth stage. ifenkwe and odurukwe (1990) reported that potato yields increased with delayed sowing in association with maize while maize yields decreased as its sowing date was delayed. functional relationship between shading occurred by maize plant and tuber yield of potato indicated that tuber yield was negatively correlated to shading occurred by maize canopy in potato maize intercropping system (fig. 2). the functional relationship suggested that 93% (r2=0.928) of the variation in yield of potato could be explained from the variation in shading. on an average, yield of potato could be decreased at the rate of 0.311 t ha-1 with an increase in 1% of shading. 14 begum et al. leaf area index of potato and maize leaf area development in intercropped potato and maize are presented in figs. 3 and 4. the lai in potato and maize varied significantly in all the intervals up to harvest. the lai increased sharply with the advancement of time up to 60 dap in potato and 110 das in maize and thereafter decreased might be due to leaves senescence. the highest lai (2.60) was observed in t11 (sole potato) at 60 dap. lais of potato were similar in monoculture as well as when maize was intercropped with potato 30 and 40 dapp and markedly differed when maize was intercropped simultaneous, 10 and 20 dapp. 0 10 20 30 40 50 60 70 80 90 30 40 50 60 70 80 90 s h a d in g (% ) days after planting fig. 1 shading (%) on potato by maize canopy in potato + maize intercropping systern over days after planting of potato ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp y = -0.3116x + 28.138 r² = 0.9285 0 5 10 15 20 25 0 20 40 60 y ie ld o f p o ta to (t h a -1 ) shading (%) fig. 2 functional relationship between shading ocurred by maize plant and tuber yield of potato in potato maize intercropping 15 system productivity of potato + maize intercropping as affected by sowing date more or less similar result was observed by islam (2002). lai of maize was highest in monoculture which was closer to the lai of maize grown simultaneously. but lai of maize reduced considerably when it was sown 10, 20, 30 and 40 dapp. similar result was reported by watiki et al. (1993) when cowpea was grown in association with maize. in all treatments the lai of hybrid maize were higher than those of composite maize. it might be due to varietal character (alam, 2003) due to different lai in different varieties of maize. total dry matter of potato and maize total dry matter (tdm) of intercropped potato and maize increased progressively over time and there was significantly difference in the pattern of biomass accumulation at different sowing date of maize (fig. 5 and 6). tdm increased sharply up to 60 dap and 110 das in potato and maize, respectively, and then increased slowly up to harvest. sole potato produced higher tdm than any other intercropped potato. intercropped potato faced different levels of shading from different sowing dates of maize and subsequently accumulated lower dry matter (kephart et al., 1992). the higher tdm of maize was found in monoculture and simultaneous sown with potato did not differ markedly but sharp difference occurred when maize was sown 10, 20, 30 and 40 dapp. total dry matter accumulation in pure stand maize and earlier sown were higher than those sown in later and the lowest dry matter was found when maize was sown 40 dapp. earlier sowing of maize showed better competitiveness of nutrients over late sown maize and reduced dry matter of late intercropped maize. the tdm of potato and maize was found positively correlated with tuber yield (r = 0.99) and grain yield (r = 0.67), respectively. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 30 45 60 75 harvest l a i day after planting fig. 3. lai of potato in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp 0.0 1.0 2.0 3.0 4.0 5.0 30 50 70 90 110 harvest l a i days after sowing fig. 4. lai of maize in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp 16 begum et al. crop growth rate of potato and maize crop growth rate of potato increased sharply up to 60 dap and thereafter declined rapidly till harvest. crop growth rate of intercropped potato with maize sown at 30 and 40 days after potato planting were similar to that of sole potato. but it was significantly lower when maize was sown simultaneously or 10 and 20 dapp. it might be due to reduction of leaf area and lower light availability to underneath potato canopy. demagante and zaag (1988a) reported that early shading (planting on wards) had a strong detrimental effect on tuber bulking rate with more shad. irrespective of sowing date, cgr of maize (both varieties) increased progressively with time and reached peak at 110 das then declined till harvest in monoculture. similar result was found by alom (2007) and the earlier sowing of maize (simultaneous, 10 and 20 days after potato planting) reached peak at 110 das and delayed sown maize (30 and 40 dapp) reached peak at 70-90 das. earlier attainment of peak in dry matter accumulation in plant at late sown maize might be due to shortening of growth period with increase of temperature at later growth stage. there was a trend for higher cgr in sole cropping compared to the intercropped due to less competition among the plants for growth resources like nutrient, air, moisture, solar radiation etc. kumar et al. (2000) also reported similar results. the cgr of potato and maize was found positively correlated with tuber yield (r = 0.98) and grain yield (r = 0.68), respectively. 0 200 400 600 800 1000 30 45 60 75 harvest t d m (g m -2 ) day after planting fig. 5. tdm of potato in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp hm sown 30 dapp cm sown 30 dapp hm sown 40 dapp cm sown 40 dapp sole potato 0 500 1000 1500 2000 2500 3000 30 50 70 90 110 harvest t d m (g m -2 ) days after sowing fig. 6. tdm maize in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp hm sown 30 dapp 17 system productivity of potato + maize intercropping as affected by sowing date yield and yield components of potato yield and yield components of potato were significantly affected in potato + maize intercropping (table 1). significant variation was observed in number of stems m-2, number of tubers hill-1, tuber weight hill-1 and tuber yield. the maximum number of stems m-2 was observed in sole potato (t11) which was statistically similar with maize sown after 30 and 40 days of potato planting (t7, t8, t9 and t10) and the lowest in potato + hm sown simultaneously (t1). similar trend was observed in number of tubers hill-1, tuber weight hill-1 and tuber yield. the maximum tuber yield of potato was recorded in sole potato (22.50 t ha-1) which was statistically similar with maize sown after 30 and 40 days of potato planting and it might be due to the early– bulging period of tuber which was shading free and cooling effect of shading during later growth stage of potato which favoured tuber bulging for longer period and ultimately increased tuber yield in maize sown 30 and 40 dapp. kuruppuarachchi (1990) also observed similar results in potato + maize intercropping. he reported that higher tuber yield where maize was sown delayed after potato planting. maize sown simultaneously with potato gave the lowest tuber yield which was statistically similar with maize sown 10 dapp. it might be due to lower light transmission during the tuber bulging period which reduced tuber yield. tuber yield in different treatments were attributed to the cumulative effect of yield components. table 1. yield and yield components of potato in potato maize intercropping as affected by sowing date of maize treatments hills m-2 (no.) stems m-2 (no.) tubers hill-1 (no.) tubers wt. hill-1 (g) tuber yield (t ha-1) t1= ss of potato & hm 6.00 20.00d 5.50c 301.88d 13.10c t2= ss of potato & cm 6.20 20.00d 5.55c 301.25d 13.15c t3= hm sown 10 dapp 6.40 23.30c 5.93bc 335.12c 14.20bc t4= cm sown 10 dapp 6.40 23.33c 6.07bc 336.75c 14.50b t5= hm sown 20 6.40 26.00b 6.20b 347.50c 15.50b 0 5 10 15 20 25 30 30-45 45-60 60-75 75-harvest c g r (g m -2 d -1 ) days after planting fig. 7. cgr of potato in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp 0 10 20 30 40 50 30-50 50-70 70-90 90-110 110harvest c g r (g m -2 d -1 ) days after sowing fig. 8. cgr of maize in potato + maize intercropping ss of potato & hm ss of potato & cm hm sown 10 dapp cm sown 10 dapp hm sown 20 dapp cm sown 20 dapp 18 begum et al. dapp t6= cm sown 20 dapp 6.50 26.18b 6.30b 348.75c 15.80b t7= hm sown 30 dapp 6.50 31.55a 8.40a 495.75b 21.50a t8= cm sown 30 dapp 6.70 31.66a 8.45a 495.72b 21.50a t9= hm sown 40 dapp 6.70 32.00a 8.50a 501.10b 21.50a t10= cm sown 40 dapp 6.70 32.66a 8.60a 501.12b 21.60a t11= sole potato 6.70 33.33a 8.80a 535.70a 22.50a level of significance ns 0.01 0.01 0.01 0.01 cv (%) 4.05 3.42 3.61 3.45 4.70 in a column figures having common letter (s) do not differ significantly as per dmrt yield and yield components of maize yield and yield components viz., number of cobs m-2, number of grains cob-1, 1000grain weight and grain yield of maize were influenced significantly under different intercropping (table 2). the maximum cobs m-2 (6.13) was recorded in t12 (sole hybrid maize) which was followed by t1. the lowest number of cobs m -2 (5.33) was recorded in cm sown 40 dapp. there was no significant variation observed when maize was intercropped with potato but it reduced gradually with delayed sown of maize. it might be due to lower number of maize population. in delayed sown maize, germination of maize was affected and seedlings growth was hampered due to heavy shade of potato canopy. as a result, poor growth as well as lower number of cobs m-2 was observed. similar result was observed by zaag and demagante, 1990. number of cobs m-2 of maize was found positively correlated with grain yield (r = 0.94). the highest number of grains cob-1 and 1000-grain weight were observed in sole hybrid maize which was statistically different from all other treatments (table 2). in general, the highest number of grains cob-1 was observed in monoculture due to the plants having more space, light and nutrient in sole cropping (moula et al., 2000). on the other hand, it was decreased in intercropped situation depending upon the sowing times (table 2). number of grains cob-1 gradually reduced with delaying sown of maize. it might be associated with intense competition for growth resources and high temperature at later growth stage (islam, 2002). grain yield of maize almost resembled to its yield contributing characters observed sown at different dates with potato (table 2). the maximum grain yield (11.26 t ha-1) was observed in sole hybrid maize which was statistically at par with hybrid maize simultaneous sowing with potato. it showed that hybrid maize and respective intercrops were higher yielder which might be due to cumulative effect of better yield attributes. on the other hand, composite maize and respective intercrops were lower yielder might be due to poor yield attributes. higher yield of maize was observed in monoculture compared to respective intercropped might be due to no intercrop competition for light, nutrients, moisture and space. yield of maize was gradually decreased with delaying sowing due to hot temperature that shortening the growth period at later stage. ifenkwe and odurukwe (1990) also reported that potato yields increased with delay sowing in association with maize while maize yields decreased as its sowing date was delayed. table 2. grain yield and yield components of maize in potato +maize intercropping as affected by sowing date of maize treatments cobs m-2 (no.) grains cob-1 (no.) 1000-grain wt.(g) grain yield (t ha-1) 19 system productivity of potato + maize intercropping as affected by sowing date t1= ss of potato & hm 5.97a 535.18b 347.53ab 9.43ab t2= ss of potato & cm 5.45c 398.87de 346.90ab 6.00de t3= hm sown 10 dapp 5.92a 500.40bc 342.25b 9.07b t4= cm sown 10 dapp 5.45c 380.91de 340.63b 5.60de t5= hm sown 20 dapp 5.92a 483.53bc 335.50b 8.57bc t6= cm sown 20 dapp 5.40c 371.67e 332.63b 5.36e t7= hm sown 30 dapp 5.87a 470.53bc 327.65b 8.17bc t8= cm sown 30 dapp 5.35c 355.20e 324.72b 5.00e t9= hm sown 40 dapp 5.81ab 450.58cd 320.04b 6.75cde t10= cm sown 40 dapp 5.33c 345.25e 319.15b 4.70e t12= sole hm 6.13a 610.20a 376.77a 11.26a t13= sole cm 5.50bc 500.00bc 350.33ab 7.50bcd level of significance 0.01 0.01 0.01 0.01 cv (%) 2.54 6.82 4.26 12.37 in a column figures having common letter (s) do not differ significantly as per dmrt intercrop efficiency potato equivalent yield (pey) and economic performance of potato + maize intercropping have been presented in table 3. intercrop productivity was evaluated by equivalent yield (bandyopadhyay, 1984). the highest pey (31.30 t ha-1) was observed when hybrid maize sown at 30 dapp. monetary advantage was estimated following shah et al. (1991). the highest gross return (tk. 426925 ha-1), gross margin (tk. 282680 ha-1) and benefit cost ratio (2.79) were observed in the same treatment t7 (hm sown 30 dapp). table 3. equivalent yield and economic performance of the component crops in potato maize intercropping as affected by sowing date of maize treatments potato equivalent yield (t ha-1) gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio t1 24.47 244700 112322 132378 2.18 t2 20.30 203000 112322 90678 1.81 t3 25.08 250800 112322 138478 2.23 t4 20.92 209200 112322 96878 1.86 t5 25.78 258800 112322 146478 2.30 t6 22.23 222300 112322 109978 1.98 t7 31.30 313000 112322 200678 2.79 t8 27.50 275000 112322 162678 2.45 t9 29.60 296000 112322 183678 2.64 t10 27.24 272400 112322 160078 2.43 t11 22.50 225000 97943 127057 2.30 t12 13.51 135100 62020 73080 2.18 t13 9.00 90000 57690 32310 1.56 market price (tk. kg-1): potato 10, maize 12. conclusion hybrid maize sown 30 days after potato planting was found the most productive and profitable intercropping system for getting higher potato equivalent yield and monetary advantage without affecting the main crop yield. 20 begum et al. references ahmed, f., m. n. islam, m. t. rahman, m. a. jahan and m. s. a. khan. 2010. leaf area index, radiation interception, dry matter production and grain yield of hybrid maize as influenced by plant spacing. bangladesh agron. j. 13(1&2): 51-58. alam, m. z. 2003. influence of planting dates and nitrogen levels on growth, grain yield and nitrogen utilization of barley. phd dissertation, crop physiology laboratory, dept. botany, rajshahi univ., bangladesh. alom, m. s. 2007. performances of different hybrid maize (zea mays l.) varieties under intercropping systems with groundnut (arachis hypogaea l.) and mungbean (vigna radiata l.). phd thesis, dept. of botany, rajshahi univ., rajshahi, bangladesh. akhteruzzaman, m., m. n. islam, b. l. nag and m. t. rahman. 2008. productivity of potato-hybrid maize intercropping under different fertilizer levels. eco-friendly agril. j. 1(5): 300-303. bandyopadhyay, s. n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph.d. dissertation, indian agril. res. inst., new delhi. barc (bangladesh agricultural research council). 2005. fertilizer recommendation guide. bangladesh agril. res. coun. (barc), farmgate, dhaka-1215. pp.73-99. begum, s., m. n. islam, m. t. rahman, j. a. chowdhury and m. i. haque. 2010. suitability study of different chilli varieties for intercropping with sweet gourd. j. expt. bios. 1(2): 1-4. cimmyt office in bangladesh. 2006. maize whole family training. in: food security in bangladesh: improving wheat, maize and papaya production and impacts of arsenic contamination. project annual report for 2005-2006. pp. 31-44. demagante, a. l. and v. p. zaag. 1988. the response of potato (solanum spp.) to photoperiod and light intensity under high temperatures. potato res. 31: 73-83. gardner, f. p., r. b. pearce and r. l. mitchell (eds.). 1985. growth and development. physiology of crop plants. lowa state univ. press, ames, usa. pp.187-208. ifenkwe, o. p. and s. o. odurukwe. 1990. potato/maize intercropping in the jos plateau of nigeria. field crops res. 25: 73-82. islam, m. n. 2002. competitive interference and productivity in maize-bushbean intercropping system. ph.d. dissertation, dept. agron., bangabandhu sheikh mujibur rahman agril. univ., gazipur, bangladesh. islam, m. n., m. a. hossain, m. s. a. khan, b. l. nag, m. a. i. sarker, m. t. rahman and i. m. ahmed. 2007. fertilizer management in hybrid maizesweet potato intercropping systems. bangladesh j. crop sci. 18(1): 89-94. kephart, k. d., d. r. buxton and s. e. taylor. 1992. growth of c3 and c4 perennial grasses in reduced irradiance. crop sci. 32: 1033-1038. kumar, c. a., s. kumar, g. p. srivastava and s. kumar. 2000. production potential and fertilizer economy in winter maize + potato based intercropping system. orissa j. hort. 28(1): 51-55. kuruppuarachchi, d. s. p. 1990. intercropped potato (solanum spp.): effect of shade on growth and tuber yield in the northwestern recosol belt of sri lanka. field crops res. 25: 61-72. mahfuza, s. n., m. n. islam, a. hannan, m. akhteruzzaman, and s. begum. 2012. intercropping 21 system productivity of potato + maize intercropping as affected by sowing date different vegetables and spices with pointed gourd. j. expt. biosci. 3(1): 77-82. moula, m. g., s. begum, m. a. rahman and m. a. quayyum. 2000. effect of row spacing and nitrogen levels on the yield and yield attributes of maize. bangladesh j. agril. sci. 27: 5-6. santalla, m., p. a. casquero, a.m. de ron. 1999. yield and yield components from intercropping improved bush bean cultivars with maize. agron. crop sci. 183: 263-269. shah, n. h., p. k. koul, b. a. khanday and d. kachrov. 1991. production potential and monetary advantage index of maize intercropped with different grain legumes. indian j. agron. 36(1): 23-28. watiki, j. m., s. fukai, j. a. banda and b. a. keating. 1993. radiation interception and growth of maize/cowpea intercrop as affected by maize plant density and cowpea cultivar. field crops res. 35: 123-133. zaag, v. p. and a .l. demagante. 1990. potato (solanum spp.) in an isohyperthermic environment. v. intercropping with maize. field crops res. 25: 157-170. accumulation of silicon and minerals in rice grain during the grain filling period bangladesh agron. j. 2016, 19(2): 125-137 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling tahmid hossain ansari1, kozo iwasaki2, tetsushi yoshida2, yoshinori yamamoto2 and akira miyazaki2 bangladesh rice research institute, gazipur 1701, bangladesh. 2faculty of agriculture, kochi university, japan 783-8502 *corresponding author: tahmidhansari@yahoo.com key words: rice cultivar, rice hull, brown rice, grain filling, silicon, nutrient elements abstract rice varieties tadukan (indica), nanjing 11(indica), nipponbare (japonica) and arborio (javanica) were tested to find out the content and accumulation pattern of si in the hull and brown rice during the grain filling periodand the changes in the weight or the contents of n, p, k, ca and mg both in the hull and brown rice. the largest increment in the hull weight during heading to maturity was observed for arborio. the content of si in the hull and brown rice increased gradually until 30 days after heading. at maturity, the amount of si in the brown rice was one twentieth of the hull, irrespective of the cultivars. during the gfp, the increment of si content was highest in arborio among the cultivars, and the increase of si content in the hull of was more remarkable than that of si concentration. furthermore, si concentration in the hull of tadukan was comparable to arborio, despite the low si content. these results suggested that the high amount of si in the hull of arborio was accomplished by the high number of silica cells on the large grain surface rather than the increased deposition of si in each silica cell. both the content and concentration of n and p in the hull decreased until maturity and twas negatively related to the accumulation of si in the hull. in brown rice, the content of these elements increased with time although the changes in concentrations were slight andmost pronounced in arborio. therefore, it was supposed that the heavy accumulation of si in the hull was the cause of enhanced accumulation of other elements in the brown rice. in addition, observation of si distribution on the abaxial surface of lemma by electron-probe x-ray microanalysis revealed heavy deposition of si on the dentate protuberances of the hull, which was supposed to be one of the reasons for different hull weight among the cultivars. introduction silicon (si) has been recognized as an agronomical essential element for increasing and/or sustaining the rice production (takahashi et al., 1990; epstein, 1994; savant et al., 1997; hassanuzzaman et al., 2014). adequate supply of si has been reported to induce resistance/tolerance in the rice plant to biotic and abiotic stress (okuda and takahashi, 1965; yamauchi and winslaw, 1987; hossain et al., 1999; ma, 2004; ma and yamaji, 2006; hassanuzzaman et al., 2014). also, several researchers have shown the improvement of physiological characteristics and increase of dry matter production by si application in rice (ma et al., 1989; liang et al., 1994). at the reproductive growth stage, si can increase the number of spikelets on the secondary branch, the ripening percentage, and the weight of grains (seo and ota, 1983; nhan et al., 2012). mizuno (1987) reported that the hulls of poor quality milky-white grains are generally low in si content, which is directly proportional to the si content in the straw. according to inanaga et al. (2002), si may positively 126 ansai et al. affect the cell division and formation of cell walls in the spikelet before heading. these studies indicate that si plays an important role in hull formation which in turn influences grain quality. besides the above mentioned physiological importance, si in the rice hull has been attracting the attention as an environmentally friendly soil amendment. since large amounts of si absorbed by the rice plants are deposited as amorphous sio2 mainly in the leaves and hulls, their utilization as soil amendments is effective for plant si recycling (hashim et al., 1996; savant et al., 1997). therefore, the determination of si concentrations in the hulls of various rice cultivars would give valuable information for the utilization of rice hulls. silicon regulation on other mineral nutrient uptake indicated that si fertilization made soil phophorus (p) more available, potassium (k) uptake improved and a better absorption of nitrogen (n) and calcium (ca) to plants (eneji et al., 2008; mali and aiery, 2008a, 2008b). in this study, the content and accumulation pattern of si in the hulls and brown rice during the grain filling period of several cultivars, and compared their relations to the changes in the weight and in the contents of other mineral elements in the hulls and brown rice. furthermore, the differences in morphological structure and si distribution on the abaxial surface of the rice hull of different cultivars were examined by electron-probe x-ray microanalysis. materials and methods plant material and sampling a field experiment was conducted in 2001 at a paddy field of grey lowland soil (typic endoaquepts) in faculty of agriculture, kochi university, japan. the surface soil (0-15 cm) with characteristics of ph (h2o, 1:2.5 w/v), 5.40; ec, 0.072 ds m -1; total n, 1.17 g kg-1; total c, 12.7 g kg-1; exchangeable cations ca, 2.87 cmolc kg -1; mg, 0.38 cmolc kg -1; k, 0.26 cmolc kg -1; and cec, 7.67 cmolc kg -1. basal fertilizer was supplied at the rate of 100 kg n, 100 kg p2o5, and 100 kg k2o ha -1 by using a coated slow release fertilizer (e-80, 140 d-type, kumiai, co. ltd.). using nh4cl, additional 20 kg n ha -1 was also applied with the slow release fertilizer. silicate fertilizers were not incorporated in the field throughout the cultivation. four rice (oryza sativa l.) cultivars tadukan (indica), nanjing 11 (indica), nipponbare (japonica), and arborio (javanica) were selected. grain characteristics of the above mentioned cultivars are shown in table 1. two seedlings of 19 days old of each cultivar per hill were transplanted with spacing was 30 cm × 15 cm.other cultural conditions were conventional ones. plots of each cultivar were arranged following the randomized block design with two replications. table i. characteristics of grains of different cultivars. cultivar ecospecies/ grain size length width thickness volume type (mm) tadukan indica small 11.79 c 2.64 a 1.87 a 24.73 a nanjing 11 indica medium 10.43 b 3.87 b 2.39 b 30.46 c nipponbare japonica medium 9.05 a 4.13 c 2.47 b 28.20 b arborio javanica large 12.28 d 4.87 d 2.58 c 47.08 d all the means for each parameter are average of 50 seeds. 127 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling means in a column do not differ significantly for the same letter by dmrt at 5%. measurement of seeds was done by vedio micrometer (vm-30, olympus co. ltd.). ten panicles of equal size were collected from different spots in each plot at heading, 10 days after heading (dah), 20 dah, 30 dah and at maturity. all of the grains from panicles in each plot were mixed and composite samples were obtained. all of the spotted, distorted or abnormal seeds were discarded from the samples. in every composite sample, each grain was separated into a hull and a brown rice, and their dry weights were recorded. the contents of si and other mineral elements in the samples were determined by using an inductively coupled plasma atomic spectrometry (icp-aes, shimadzu icps 1000iv) after fusion with lithium metaborate (goto and ninaki, 1991), unless otherwise stated. potassium and mg were determined by using atomic absorption spectrometer (shimadzu aa-610s), and n was determined according to the kjeldhal method. electron probe x-ray microanalysis (epma) of lemma inflorescence bract lemma and palea was dissected from the mature seeds at maturity. lemma was then cut along the length. prepared lemma was fixed to aluminum disks with adhesive and was coated with a carbon layer approximately 30nm thick using a vacuum evaporator (jeol, jee-400). analysis was carried out using a wavelength dispersive type electron probe x-ray microanalyzer (jeol, jxa-8600mx). the analysis of si on the abaxial surface around the tip area of the hull were conducted at an accelerating voltage of 15 kv, a sample current of 5~10-8a, and with a beam diameter of 5 ƒêm. the x-ray spectrometer was peaked for the first order silicon kƒƒ line (0.7126 nm), using a thallium acid phthalate (tap) diffracting crystal. the detection of si was performed by x-ray distribution mapping with stage scanning mode. morphological observation was performed using the secondary electron scanning microscope (sem) image at a sample current of 2~10-9a. least significant difference (lsd) for the comparison of any pair of the data were analysed. results and discussion dry weights of hull and brown rice among four cultivars, the largest increase in the hull weight was observed for arborio and the increment was 2.5 mg, while the increases in other three cultivars were less than 1.5 mg (fig. 1). at the same sampling time, the hull weight was maximum in arborio, followed by nanjing 11, nipponbare and tadukan. the difference of the hull weight between arborio and nanjing 11 was larger than the other three cultivars. from 10 dah to the maturity, the weight of the brown rice of arborio increased from 7.5 to 35 mg, which was the largest increase among four cultivars, while the increment in the weight of the brown rice of other three cultivars was less than 15 mg (fig. 1b). at every sampling time, the maximum dry weight among the cultivars was observed for arborio, followed by nipponbare, nanjing 11, and tadukan, except for the sampling at 10 dah but no significant difference was observed among four cultivars. due to the significant weight increase in the brown rice of arborio during the late stage of the grain filling period, the difference in the weight of the brown rice between arborio and the other three cultivars was remarkable especially at 30 128 ansai et al. dah and at maturity. contents and concentrations of si and other elements in hull the lowest content of si per hull was found at heading in all the cultivars (fig. 2). the content increased gradually up to 30 dah and then remained almost no change. this tendency was most remarkable for arborio which accumulated 0.35 mg of si in the hull during the period from heading to 30 dah, while other three cultivars accumulated less than 0.20 mg si. as a result, si content per hull at every sampling time was highest in arborio and no significant difference was found among the other three cultivars. on the other hand, si concentrations in the hulls of nanjing 11 and nipponbare increased significantly from heading to 20 dah and those of tadukan and arborio continued significant increasing until 30 dah (table 2). different from the si content per hull, the remarkable difference in si concentration between arborio and the other three cultivars was not observed, although the si concentrations of tadukan and arborio were higher than those of nanjing 11 and nipponbare at every sampling time. table 2. concentrations of si and other elements in the hulls during the grain filling period. element cultivar heading 10 dah 20 dah 30 dah maturity g/kg dry weight si tadukan 29.94 47.91 62.04 73.74 72.71 nanjing 11 23.81 44.27 51.98 54.48 62.58 nipponbare 25.33 37.73 52.38 59.55 62.68 arborio 33.88 53.66 65.69 77.64 71 .57 lsd(0.05) 7.65 n tadukan 11.3 6.99 5.02 4.18 3.99 nanjing 11 9.93 5.21 4.64 3.5 3.26 nipponbare 9.74 5.94 4.32 3.76 3.49 arborio 11.31 7.29 5.471 4.4 4.04 lsd(0.05) 0.96 p tadukan 1.65 1.00 0.68 0.43 0.25 nanjing 11 1.66 0.85 0.6 0.36 0.23 nipponbare 1.34 0.87 0.45 0.26 0.14 arborio 1.8 1.08 0.78 0.63 0.28 lsd(0.0s) 0.11 k tadukan 6.85 6.97 5.04 2.7 1.14 nanjing 11 6.64 5.29 5.22 5.0 2.4 nipponbare 5.3 5.67 9.77 4.7 3.72 arborio 8.95 7.03 7.48 6.19 4.72 lsd(0.0s) 1.42 ca tadukan 1.37 1.4 1.48 1.6 1.01 nanjing 11 1.19 1.39 1.41 1.37 1.45 nipponbare 1.11 0.88 1.08 1.43 1.16 arborio 1.95 2.04 2.16 2.2 1.72 lsd(0.0s) 1.42 mg tadukan 1.02 0.88 0.79 0.65 0.62 nanjing 11 1.09 0.75 0.62 0.45 0.46 nipponbare 0.84 0.59 0.29 0.22 0.23 129 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling arborio 1.2 0.91 0.71 0.59 0.52 lsd(0.0s) 0.11 contrary to the accumulation pattern of si, the contents and the concentrations of n and p in the hull were highest at heading and gradually decreased until maturity in all of the cultivars (fig. 2 and table 2). the drastic decreases in the contents of these elements were observed for arborio and nanjin 11 within 10 dah. from heading to maturity, the largest decrease in the content of n and p was recorded for arborio, followed by nanjin 11. although the contents and the concentrations of mg and k decreased in the same tendency with n and p, those of mg showed almost no change after 30 dah. in the case of k, the decrease was found clearly only during the late stage of grain filling period. the content and the concentration of ca increased until 30 dah and then decreased, except for nanjin 11 where they continued increasing gradually until maturity. the increase in the ca content until 30 dah was more pronounced in arborio than in the other three cultivars. on the other hand, the contents of the examined elements were always highest in arborio at the same sampling time, and no clear difference was observed among other three cultivars, except for the mg content of nipponbare which was significantly lower than the other cultivars after 20 dah. the concentrations of the examined elements were also highest in arborio except for mg concentrations after 20 dah. however, except for ca, the differences in the concentrations between arborio and the other three cultivars were not so large compared with those in their contents. contents and concentrations of si and other elements in brown rice the lowest content of si per brown rice was found at heading and it increased gradually until maturity in all the cultivars (fig. 3). this tendency was most remarkable for arborio which accumulated 0.02 mg of si in the brown rice until maturity, while the other three cultivars accumulated less than 0.005 mg si. irrespective of the cultivars, the si content in the brown rice at maturity was less than one twentieth of that in the hull. at every sampling time, si content per brown rice was highest in arborio and no significant difference was found among the other three cultivars. different from the si content per brown rice, only a slight increase was observed for the si concentrations in the brown rice of all the cultivars (table 3). further, the remarkable difference in the si concentration between arborio and the other three cultivars was not observed, and tadukan showed the highest si concentration at maturity. contrary to the decreasing pattern in the hulls, the contents of n, p, k, ca, and mg in the brown rice were lowest at heading and gradually increased until maturity, except for nipponbare (fig. 3 and table 3). in the case of nipponbare, slight decreases were observed between 30 dah and at maturity. from heading to maturity, the largest increase in the content of these elements was recorded for arborio and the smallest was for tadukan. the n concentration in the brown rice was almost in the similar level from 10 dah to maturity. although the large fluctuations were not observed for the concentrations of p and mg as well as n, slight increases were found for the p concentrations between 10 and 20 dah except for nipponbare, and for the mg concentrations between 20 and 30 dah of tadukan and nipponbare. in the case of k and ca, the concentrations decreased steeply between 10 and 20 dah and then very slightly until maturity. at the same sampling time, the contents of the examined elements were always highest in arborio, followed by nanjing 11 or nipponbare, and were lowest in tadukan. however, the differences between arborio 130 ansai et al. and the other three cultivars were more remarkable compared with those among the other three cultivars, especially at the late stage of the grain filling period. while the concentrations of n, p, and k were also highest in arborio, those of ca and mg were highest in tadukan at every sampling time. table 3. concentrations of si and other elements in brown rice during the grain filling period. element cultivar 10 dah 20 dah 30 dah maturity g/kg dry weight si tadukan 0.46 0.46 0.53 0.64 nanjing 11 0.36 0.41 0.42 0.47 nipponbare 0.33 0.32 0.38 0.57 arborio 0.43 0.43 0.54 0.58 lsd(0.05) 0.14 n tadukan 13.1 14.4 14.5 14.8 nanjing 11 13.55 14.95 15.75 14.6 nipponbare 11.75 12.25 13.2 12.7 arborio 16.15 16.5 17 16.55 lsd(0.05) 2.06 p tadukan 2.77 3.2 3.39 3.42 nanjing 11 3.1 3.73 3.83 3.79 nipponbare 2.5 2.52 2.94 2.62 arborio 3.39 3.86 3.95 3.87 lsd(0.05) 0.39 k tadukan 3.99 2.92 2.97 2.83 nanjing 1l 5.05 3.92 3.77 3.41 nipponbare 4.96 2.82 2.68 2.34 arborio 6 4.05 3.95 3.61 lsd(0.05) 0.39 ca tadukan 0.3 0.23 0.22 0.22 nanjing 11 0.26 0.21 0.2 0.19 nipponbare 0.27 0.16 0.16 0.15 arborio 0.26 0.17 0.17 0.15 lsd(0.05) 0.04 mg tadukan 1.19 1.19 1.38 1.45 nanjing 11 1.55 1.53 1.59 1.63 nipponbare 1.23 1.18 1.36 1.22 arborio 1.43 1.39 1.43 1.33 lsd(0.05) 0.17 morphological characteristics and si distribution on hull by using sem, the existence of trichomes and dentate protuberances arranged regularly in rows paralleled with longitudinal axis was confirmed on the outer surface 131 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling around the tip area of the hull for all of the cultivars. the number of trichomes was higher in arborio and nanjing 11, followed by tadukan and nipponbare (plate 1). the length of trichomes was longer in arborio, medium in nanjing 11 and short in tadukan. mapping of si on the outer surface of the lemma revealed heavy deposition of si on the dentate protuberances on the abaxial surface of hull, and relatively a few amounts of si were present in the trichomes. it is well known that large amounts of si absorbed by the rice plants are deposited mainly in the leaves and hulls. yoshida et al. (1962) estimated the average amounts of si in the rice hull and in the leaf sheath as 7.1% and 4.7%, respectively. the same authors reported that heavy deposition of silicon in the inflorescence bracts/husk especially on the abaxial surface was evident (yoshida et al. 1962). furthermore, electron probe microanalysis of lemma and palea of rice has revealed heavy deposition of si associated with the abaxial surface (soni and parry, 1973; balasta et al. 1989; hodson and sangstar, 1989). consistent with these previous reports, our study showed that the amount of accumulated si was much higher in the hull than in the brown rice irrespective of the cultivars of different grain size and that the accumulation pattern was similar both in the hull and in the brown rice. by the analysis of si distribution by epma and sem images, it was also confirmed for all of the cultivars that si was heavily deposited on the dentate rectangular protuberances in the abaxial surface of the hull. however, the difference in the amount of the deposited si among the cultivars was not found clearly. on the other hand, the higher amount of si was detected on the dentate rectangular protuberances than in the trichomes although soni and perry (1973) reported that a considerable amount of silicon existed in the trichomes. it seemed necessary to conduct qualitative analysis by epma in order to evaluate the amounts of si properly. the results of present study indicated that the si content and concentration in the hull of arborio (javanica type) were significantly higher than those of indicia and japonica type. these different amounts of deposition of si on the abaxial surface of the hull among the cultivars were supposed to be one of the reasons for the different weight of hull in each cultivar. the increase of si content in the hull of arborio during the grain filling period was more remarkable than that of si concentration. furthermore, the si concentration of the hull of tadukan (indica type) was comparable to that of arborio, despite the low si content. taking into consideration of these facts, the high amount of si in the hull of arborio might be accomplished by the high number of silica cells on the large grain surface rather than the increased deposition of si in each silica cell. in addition, sem image of the hull surface of arborio revealed the number and the length of the trichome were higher than those of the other cultivars. most of the absorbed si by plants remains in the apoplast and is deposited after water evaporation at the termini of the transpiration stream (epstein, 1994; marschner, 1995). since the trichomes have a large surface area, the translocation and the accumulation of si in the hull of arborio might be enhanced after water evaporation compared with the other cultivars with less or short trichomes. in the present study, it was indicated that, except for ca, both of the content and concentration of all the macro elements in the hull decreased until maturity, and this tendency was negatively related to the accumulation of si in the hull. contrary to these decrements, the content of these elements in the brown rice increased with time although the changes in the concentrations were slight except that the concentrations of k and ca decreased at early stage of the grain filling period. these results 132 ansai et al. suggested that the heavy accumulation of si in the hull was the cause of the enhanced accumulation of the other elements in the brown rice. lu et al. (2013) reported the elemental distribution of ca was more in hull (63.8%) than brown rice (36.2%) and this was vice versa for k (67.9% for brown rice). they also showed that the local distribution of k was highly concentrated in the embryo and ca was preferentially the results of this study indicated that the decreases of the n and p contents in the hull and the increase of these elements were most remarkable for arborio. as mentioned already, the highest content and the concentration of si in the hull was observed for this cultivar throughout the grain filling period. therefore, it was supposed that lower transpiration caused by the heavy accumulation of si on the hull enhanced the translocation of the other elements into the brown rice. in addition, the ca concentration in the hull of arborio was significantly higher than that of the other cultivars throughout the grain filling period, and that in the brown rice was lower. these results suggest that some of the accumulated si by arborio were co-precipitated with ca in the hull. conclusion in summary, the present study indicated that the amount of si in the hull of arborio was higher than that of tadukan, nanjing 11 and nipponbare. the results also suggested that the hull with the high accumulation of si might enhance the translocation of other elements such as n and p from the hull into the brown rice. further, the different amounts of deposition of si on the abaxial surface of the hull among the cultivars were supposed to be one of the reasons for different weight of the hull in each cultivar. the fact that the hull of the javanica type arborio showed high si content and concentration could be utilized for the production of soil amendments with high si contents, and could help to breed high yielding rice cultivars. acknowledgements the study was carried out under the mext (monbukagakusho) scholarship, japan. kochi university, japan provided the research facilities and bangladesh rice research institute (brri) granted the study leave to conduct the experiment. references balasta, m. l. f. c., c. m. perez, b. o. juliano and c. p. villareal. 1989. effects of silica level on some properties of oryza sativa straw and hull. can. j. bot. 67: 2356-2363. eneji, a. e., s. inanaga, s. muranaka, j. li, t. hattori, p. an and w. tsuji. 2008. growth and nutrient use in four grasses under drought stress as mediated by silicon fertilizers. j. plant nutr. 31: 355-365. epstein, e. 1994. the anomaly of silicon in plant biology. proc. natl. acad. sci. usa, 91: 11-17. hasanuzzaman, m., k. nahar. and m. fujita. 2014. silicon and selenium: two vital trace elements that confer abiotic stress tolerance to plants. emerging technologies and management of crop stress tolerance: biological techniques-1, pp. 377-422 (http://www.sciencedirect.com/science/article/pii/b9780128008768000163) http://www.sciencedirect.com/science/article/pii/b9780128008768000163 133 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling hashim, a. b., h. aminuddin and k. b. siva. 1996. nutrient content of rice husk ash of some malaysian rice varieties. pertanika j. trop. agric. sci. 19(1): 77-80. hodson, m. j. and a. g. sangstar. 1989. silica deposition in the inflorescence bracts of wheat (triticum aestivum). ii. x-ray microanalysis and backscattered electron imaging. can. j. bot. 67: 281-287. hossain, k. a., t. horiuchi and s. miyagawa. 1999. effects of powdered rice chaff application on the si and n absorption, lodging resistance and yield in rice plants (oryza sativa l.). plant prod. sci. 2: 159-164. islam, a. and r. shaha. 1969. effects of silicon on the chemical composition of rice plants. plant soil. 30: 446-458. lu, l., s. tian, h. liao, j. zhang, x. yang and j. m. labavitch. 2013. analysis of metal element distribution in rice (oryza sativa l.) seeds and relocation during germination based on x-ray flourescene imaging of zn, fe, k, ca and mn. plos one. 8(2): e57360. inanaga, s., y. higuchi and n. chishaki. 2002. effect of silicon application on reproductive growth of rice plant. soil sci. plant nutr. 48: 341-345. liang, y. c., t. s. ma, f. j. li and y. j. feng. 1994. silicon availability and response of rice and wheat to silicon in calcareous soils. commun. soil sci. plant anal. 25: 2285-2297. ma, j. f. 2004. role of silicon in enhancing the resistance of plants to biotic and abiotic stresses. soil sci. plant nutr. 30: 417-425. ma, j. f. and n. yamaji. 2006. silicon uptake and accumulation in higher plants. trends plant sci. 11: 392-397. ma, j. f., k. nishimura and e. takahashi. 1989. effect of silicon on the growth of rice plant at different growth stages. soil sci. plant nutr. 35: 347-356. mali, m. and n. c. aery. 2008a. influence of silicon on growth, relative water contents and uptake of silicon, calcium and potassium in wheat grown in nutrient solution. j. plant nutr. 31:1867-1876. mali, m. and n. c. aery. 2008b. silicon effects on nodule growth, dry matter production, and mineral nutrition of cowpea (vigna unguiculata). j. plant nutr. soil sci. 171: 835–840. marschner, h. 1995. silicon. in: mineral nutrition of higher plants, 2nd edn., academic press, london, pp. 417-435. mizuno, n. 1987. effects of silica on hull weight and ripening of rice plants. j. plant nutr. 10: 21-59. nhan, p. p., n. t. dong, h. t. nhan and n. t. m. chi. 2012. effect of orymaxsl and siliysolms on growth and yield of mtl560 rice. world appl. sci. j. 19(5): 704709. okuda, a. and e. takahashi. 1965.the role of silicon. in: the mineral nutrition of the rice plant, john hopkins press, baltimore, md, pp. 126-146. savant, n. k., g. h. snyder and l. e. datnoff. 1997. silicon management and sustainable rice production. adv. agron. 58: 151-199. seo, s. w. and y. ota. 1983. role of hull in the ripening of rice plant. vii. effect of supplying of silica and potassium during reproductive growth stage on the form 134 ansai et al. and function of hulls. nippon sakumotsu gakkai kiji. 52: 73-79 (in japanese). soni, s. l. and d. w. parry. 1973. electron probe microanalysis of silicon deposition in the inflorescence bracts of the rice plant (oryza sativa). am. j. bot. 60: 111-116. takahashi, e., j. f. ma and y. miyake. 1990. the possibility of silicon as an essential element for higher plant. comment agric. food chem. 2: 99-122. yamauchi, m. and m. d. winslaw. 1987. silica reduces disease on upland rice in a high rainfall area. int. rice res. newslett, 12: 22-23. yoshida, s., y. ohnishi and k. kitagishi. 1962. chemical forms, mobility, and deposition of silicon in rice plant. soil sci. plant nutr. 8: 15-21. 135 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling fig. 1. dry weight of a hull (a) and a brown rice (b) of different cultivars at different 136 ansai et al. days after heading (dah). bar indicates the lsdvalue for crop-stage × variety at 5%. 137 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling fig 2. contents of si and other elements in the hull of different cultivars during grain filling period. bar indicates the lsd (0.05) value for crop-stage × variety. 138 ansai et al. fig. 3. contents of si and other elements in the brown rice of different cultivars during grain filling period. bar indicates the lsd(0.05)value for crop-stage × 139 status of nutrient elements in rice grain in relation to silicon accumulation pattern during grain filling variety. plate 1. secondary electron images (left side) and corresponding x-ray distribution of si (right side) on the adaxial surface of the hulls (lemma) of different cultivars, 140 ansai et al. (a) tadukan (b) nanjing 11 (c) nipponbare and (d) arborio. microsoft word 12. baj-233_revised.docx bangladesh agron. j. 2016, 19(1): 99-108 performance of soybean under different levels of phosphorus and potassium m. khanam1, m.s. islam2, m.h. ali2, imtiaz faruk chowdhury3 and *s.m. masum3 department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh *corresponding author’s: smmasum607@yahoo.com key words: soybean, nodule, oil legume, phosphorus, potassium abstract a field experiment was conducted at the sher-e-bangla agricultural university farm, dhaka, bangladesh during december 2013 to april 2014 to evaluate the effect of phosphorus (p0: 0 kg tsp ha-1, p1: 100 kg tsp ha-1, p2: 175 kg tsp ha-1, p3: 250 kg tsp ha-1) and potassium (k0: 0 kg mop, k1: 60 kg mop ha-1, k2: 120 kg mop ha-1, k3: 180 kg mop ha-1), and their combinations on growth and yield of soybean (glycine max). number of nodules plant-1, number of filled pods plant-1, number of seeds pod-1, 1000-seed weight, seed yield, biological yield and harvest index increased significantly up to 175 kg ha-1 tsp. on the other hand, numbers of nodules plant-1, number of filled pods plant-1, length of pod, number of seeds pod-1, 1000-seed weight, seed yield, stover yield and biological yield were enhanced significantly up to 120 kg ha-1 mop. the treatment of combined phosphorus @ 175 kg ha-1 and potassium @ 120 kg mop ha-1 depicted the highest number of filled pods plant-1 (63.00), length of pod (3.16 cm), number of seeds pod-1 (3.11) vis a vis the highest (3.67 t ha-1) seed yield. thus, the combined application of 175 kg ha-1 tsp and 120 kg ha-1 mop could be the optimum for getting maximum yield of soybean. introduction soybean (glycine max l. merril), the most important oil seed crop in the world, belongs to the family fabaceae, under sub family faboideae provides vegetable protein for millions of people and ingredients for hundreds of chemical products. it has been classified more as an oil seed crop than as a pulse (devi et al., 2012). it is also known as an important grain legume of the world and a new prospective crop for bangladesh (rahman et al., 2011). bangladesh has to import 1.8 million tonnes of soybean cooking oil in each year at the cost of more than 1.5 billion usd and soybean meal with about 25.51 million usd per year (quaiyum et al., 2015). recently the soybean production area is increasing and in the year 2013 it reached to above 61000 ha (chowdhury et al., 2014). the world average yield of soybean is about 3 t ha-1 while it is only 1.2 t ha-1 in bangladesh (saic, 2007). this is mainly due to use of low yield potential varieties and poor agronomic management practices. however, there is a scope for improvement of this yield through judicious application of chemical fertilizers. it is reported that bangladesh could meet 40 percent of its soybean oil demand by producing soybean locally (anon, 2009). plants require phosphorus for growth throughout their life cycle, especially during the early stages of growth and development. in soybeans, the demand for p is the greatest during pod and seed development where more than 60% of p ends up in the pods and seeds (usherwood, 1998). its uptake and utilization by soybean is essential for ensuring proper nodule formation and improving yield and quality of the crop (anon, 2004). very high soil phosphate depressed seed protein and oil content, while yield would be low if available phosphorus was less than 30 kg p ha-1 (daff, 2010). the most important phosphorus 100 khanam et al. sources in arable soils are chemical fertilizers, though 75 to 90 percent of the phosphorus is fixed with iron, calcium and aluminums in soil (turan et al., 2006). therefore, the use of phosphate solubilizing bacteria is essential to solve the problem. it has been proven that p increases weight and number of root nodules and also can enhance the pod yield (jones et al., 1977). different reports revealed that the increase in soybean yield could not be expected when soil p concentration prevailed above 20 mg kg-1 (webb et al., 1992; borges and mallarino, 2003). potassium (k) has also an important role in regulating the water loss of plants thus help to prevent plant from necrosis. it serves as an activator of enzymes used in photosynthesis and respiration, helps to build cellulose and aids in photosynthesis by the formation of a chlorophyll precursor and finally results in quality fruits (nziguheba et al., 1998). the relatively large amounts of k is required for high yielding soybean. soybean has been found to respond to various level of k under different agroclimatic-situations (silva and bohnen, 1991). the deficiency of k at any time during the growing season of soybean reduced its pod yields; whereas, application of k fertilizers increased the number of nodules, and weight of nodules, and the number of pods plant-1 (jhones et al., 1977). despite voluminous works done at home and abroad, more research is needed to specify the amount of phosphorus and potassium for exploiting the maximum productivity of soybean, which is rather a new but promising crop in bangladesh. the purpose of the present study was to determine the optimum level of phosphorus and potash fertilizer as well as their combination for the maximum growth and yield performance of soybean. materials and methods the field experiment was conducted at research field of agronomy department, sher-ebangla agricultural university, dhaka (tejgaon series under aez no. 28) during the period december 2013 to april 2014. the experimental site was located at 23º77' n latitude and 90o3' e longitudes with an elevation of 4.0 meter from the sea level. temperature during the cropping period ranged between 17.0ºc to 26.9ºc, the humidity 58.66% to 80.25% with 10.5-11.0 hours day length and a very little rainfall was recorded. the soil (% sand 26, % silt 45, % clay 29, textural class: silty-clay, ph 5.6, % organic carbon 0.45, % n 0.03, p 20.00 ppm, k 0.10 me 100 g soil-1, and s 45 ppm) of experimental plots was slightly acidic in reaction with low (0.78%) organic matter content. the variety of soybean bari soybean-6 was used in this trial. the experiment consisted two factors with four different levels of each, such as phosphorus (p0: 0 kg tsp ha-1 = 0 kg p ha-1, p1: 100 kg tsp ha-1 = 43 kg p ha-1, p2: 175 kg tsp ha-1 = 75.25 kg p ha-1, p3: 250 kg tsp ha-1 = 107.5 kg p ha-1) and potassium (k0: 0 kg mop ha-1 = 0 kg k ha-1, k1: 60 kg mop ha-1 = 49.8 kg k ha-1, k2: 120 kg mop ha-1 = 99.6 kg k ha-1, k3: 180 kg mop ha-1 = 149.4 kg k ha-1) which was laid out in a split plot design with three replications. the fertilizer nutrients were applied in the form of urea, tsp, mop and gypsum. the size of unit plot was 2 m × 2 m and total numbers of plots were 48. the main plot received the phosphate fertilizer treatments and potassium fertilization treatments were placed in the sub plots. the applied doses of urea (60 kg ha-1) and gypsum (115 kg ha-1) as per recommended dose (frg, 2012) were applied all plots of the experimental field. triple superphosphate and muriate of potash were applied as per treatment. one-third of urea and all other fertilizers were applied at the time of final land preparation and the rest of urea was applied in two splits on 20 days after sowing (das) and 40 das. the seeds of soybean were sown on 28 december 2013 maintaining 30 cm lineline distance. the thinning operation was done for ensuring the exact plant populations. all other recommended agronomic practices were followed (bari 2013). regular observations 101 performance of soybean under different levels of phosphorus and potassium were made to see the growth stages of the crop. total nodules number was counted at 30, 60 and 90 das. three plants were collected randomly from the inner rows of each plot and counted nodule number then averaged them to have number of nodules plant-1. maturity of the crop was determined when 95% of the pods become brown in color. harvesting was done on 29 april, 2014. three sample plants were collected from each plot before harvesting for taking yield attributes data. the plants of central 1 m2 area were harvested by placing quadrates for recording yield data. the data collected on different parameters were statistically analyzed to obtain the level of significance by using mstat-c computer package program. the significant differences among the treatment means were compared by duncan’s multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). results and discussions number of nodules per plant the nodule numbers plant-1 of soybean varied significantly due to the different levels of p application at various das (fig. 1a). the treatment with tsp 175 kg ha-1 under p levels gave the maximum number of nodules (4.72, 9.99 and 4.11) at the sampling dates of 30, 60 and 90 das, respectively than the other p levels. islam et al. (2004) reported that the number of nodules plant-1 increased from 45 to 80 das and thereafter it decreased. the positive effect of p application on nodule number was confirmed by tsvetkova and georgiew (2003). the findings revealed that nodule number decreased by almost 50% in p deficient plants. rotaru (2010) reported that the nodulation process responded significantly with application of supplementary p nutrition. number of nodules plant-1 of soybean varied significantly also due to the different levels of k application at different das (fig. 1b). among k treatments 120 kg mop ha-1 gave the maximum number of nodules (11.44 and 5.42) at the sampling dates of 60 and 90 das, respectively. at 30 das, the maximum number of nodules plant-1 (4.81) was obtained from 180 kg ha-1 of mop. combined effect of different levels of p and k on number of nodules plant-1 was also significant at different das (table 1). p0: 0 kg tsp ha-1, p1: 100 kg tsp ha-1, p2: 175 kg tsp ha-1, p3: 250 kgtsp ha-1;k0: 0 kg mop, k1: 60 kg mop ha-1, k2: 120 kg mop ha-1, k3: 180 kg mop ha-1 fig. 1a-b. effect of p and k levels on number of nodules plant-1 of soybean at different das. at 30 das, maximum number of nodules (6.44) was recorded from the combination of 175 kg tsp ha-1 and 180 kg mop ha-1. at 60 das, maximum number of nodules (13.22) was a b 102 khanam et al. obtained from the combination of 100 kg ha-1 of tsp and 120 kg ha-1 of mop. at 90 das, maximum number of nodules (7.11) was recorded from the combination of 100 kg tsp ha-1 and 120 kg mp ha-1. these results showed that application of both p and k fertilizer individually increased nodulation with more response to k than p. maximum response was obtained when both elements were added together. jones et al., (1977) also reported that either p or k applied alone increased the number of nodules per plant and per unit volume of soil. applied k increased the number of nodules, total and individual weight of nodules per plant more than p, but more response was found when both p and k were applied in combination. table 1. combined effect of p and k on number of nodules plant-1 of soybean at different das number of nodules plant-1 at different das treatment combinations 30 60 90 p0k0 2.11 g 3.67e 1.44 f p0k1 2.78 fg 6.22 c-e 2.78 d-f p0k2 3.33 e-g 11.11 a-d 4.22 b-d p0k3 3.78 d-f 7.89 a-e 2.78 d-f p1k0 2.78 fg 6.44 b-e 1.33 f p1k1 3.56 d-f 10.00 a-d 3.56 c-e p1k2 4.89 b-d 13.22 a 7.11 a p1k3 3.45 e-g 12.11 ab 1.78 f p2k0 3.11e-g 5.67 de 2.89 d-f p2k1 4.11 c-f 12.00 a-c 4.11 b-d p2k2 5.22 a-c 11.67 a-c 5.33 b p2k3 6.44 a 10.67a-d 4.11 b-d p3k0 3.44 e-g 5.33 de 2.11 ef p3k1 4.33 b-e 7.89 a-e 2.99 d-f p3k2 5.22 a-c 9.78 a-d 5.00 bc p3k3 5.56 ab 6.67 b-e 2.56 d-f se 0.42 1.72 0.50 cv% 18.16 33.02 25.79 in a column means having similar letter (s) are statistically similar and those having dissimilar letter (s) differ significantly by dmrt at 0.05 level of probability number of filled pods per plant the number of filled pods plant-1 was the highest with 175 kg ha-1of tsp, which was significantly highest to that of other treatments (table 2). the maximum number of pods plant-1 of soybean (51.14) was recorded from 175 kg ha-1 tsp. the results are in agreement with the findings of singh and bajpai (1990) who reported that the number of pods plant-1 increased with increase of phosphorus rate up to a certain limit and then decreased. different levels of k-fertilizers also significantly influenced the number of filled pods plant-1 (table 2). the maximum number of pods plant-1 of soybean (53.92) was recorded from 120 kg ha-1of mop. ali et al. (1996) also reported that number of pods plant-1 was influenced significantly by potassium application. combined effect of p and k fertilizers application had significant effect on filled pods plant-1 of soybean. the highest number of pods (63.00) was recorded from 175 kg ha-1 of tsp along with 120 kg ha-1 of mop. the present results are agreed with the findings of xiang et al. (2012) who observed that combination of p& k 103 performance of soybean under different levels of phosphorus and potassium indicated that increasing amount of k application from 0 to 112.5 kg ha-1 increase pods plant1. similar trend was also observed at the rate 0 to 17 kg ha-1 of p application. pod length (cm) the effect of phosphorus on length of pods was non-significant (table 2). sardana and verma (1987) were also found the same results. whereas, the effect of potassium on length of soybean pod showed significant variation. the highest pod length (3.09 cm) was recorded from 120 kg mop ha-1. length of pod was also non-significant in combined application of p and k. shehu et al. (2010) found that combination of p and k showed non-significant effect on sesame pod length. number of seeds per pod number of seeds pod-1 of soybean showed significant variation due to different levels of phosphorus fertilization rate (table 2). the highest numbers of seeds pod-1 (2.98) was recorded with 175 kg ha-1 of tsp. hernandez and cuevas (2003) also reported significant high numbers of seeds pod-1 when 100 kg p2o5 ha-1 was applied and it was minimum in phosphorus untreated plot. these results confirmed the findings of tomar et al. (2004) who observed that significant differences in number of seeds pod-1 when different levels of phosphorus were applied. numbers of seeds pod-1 also significantly affected by various levels k fertilizer. the maximum numbers of seeds pod-1 of soybean (2.50) was recorded from 120 kg ha-1of mop. the application of k not only enhanced the availability of other nutrient but also increased the transportation of photosynthates; which might be the main reason for increase in number of seeds. different levels of p and k fertilizers in combination affected significantly the seeds pod-1 of soybean. the maximum seeds pod-1 of soybean (3.11) was recorded with combined application of tsp and mop at 175 kg ha-1 and 120 kg ha-1, respectively. weight of 1000-seed different levels of p had significant effect on 1000-seed weight of soybean (table 2). the heaviest 1000-seed weight (106.2 g) was obtained with 175 kg ha-1of tsp. similar trend of results was reported by devi et al. (2012), who observed a significant variation in 1000-seed weight at different phosphorus levels. significant variations in 1000-seed weight were also noted due to potassium levels. the application of 120 kg mop ha-1 resulted in maximum 1000-seed weight. these results are in agreement with dixit et al. (2011) who reported that the weight of 1000-seed significantly increased with the application of k fertilizer. the combination of p and k had also significant effect on 1000-seed weight of soybean. the maximum 1000-seed weight (109.1 g) was harvested with the combined application of tsp and mop@175 and 120 kg ha-1, respectively. seed yield (t ha-1) the highest soybean seed yield (3.01 t ha-1) was produced when the crop was fertilized with 175 kg ha-1of tsp (table 2). the result is in agreement with those of pauline et al. (2010), and aise et al. (2011) who reported a similar findings on seed yield of soybean under the condition of the proper p application. the decrease in seed yield at the lowest and highest p application was most likely due to the fact that the growth and development of soybean was influenced by nutrient deficiency or nutrition surplus (xiang et al., 2012. seed yield of soybean varied significantly with different levels of k fertilizer application (table 2). the maximum yield of soybean (3.16 t ha-1) was recorded from the k treatment of 120 kg mop ha-1 . deshmukh et al. (1994) obtained the highest soybean yield with an application of 60 kg k2o ha-1 at amravati and 90 kg k2o ha-1 at akola in 104 khanam et al. maharashtra state, india. more conclusive results on yield responses of soybean were obtained in experimentation magen (1997) where the yield was increased up to 100 kg k2o ha-1. the lowest seed yield of soybean was recorded from experimental plot where 0 kg of tsp and mop fertilizers was applied, that might due to the lowest performance of yield attributes under same treatment. table 2. effect of phosphorus and potassium and their combinations on yield and yield attributes of soybean. treat ments filled pods plant-1 length of pod (cm) no. of seeds pod-1 1000seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) levels of phosphorus fertilizer p0 39.34 b 2.99 1.71 c 101.5 c 2.06 c 2.94 a 5.00 b 40.94 c p1 49.83 a 3.03 2.41 b 105.3 ab 2.59ab 2.97 a 5.55ab 46.85ab p2 51.14 a 3.05 2.98 a 106.2 a 3.01 a 3.21 a 6.22 a 48.54 a p3 43.17 ab 3.01 2.38 b 103.6 b 2.49bc 3.13 a 5.62ab 43.38 bc se 3.33 ns 0.07 0.58 0.15 0.17 0.27 1.57 levels of potassium fertilizer k0 35.79 c 2.96 b 2.26 b 101.2 c 2.11 c 2.58 c 4.68 c 44.57 a k1 50.90 ab 3.02 ab 2.37 ab 104.9 ab 2.62 b 3.13 b 5.76 b 45.38 a k2 53.92 a 3.09 a 2.50 a 106.4 a 3.16 a 3.72 a 6.88 a 45.87 a k3 42.87 bc 3.01 ab 2.35 ab 104.1 b 2.25 bc 2.82 bc 5.077 bc 43.89 a se 3.33 0.04 0.07 0.58 0.15 0.17 0.27 1.57 phosphorus × potassium p0k0 32.15 c 2.92 1.62 f 96.56 f 1.78 e 2.64 bc 4.41 e 40.42 ab p0k1 40.59ac 3.02 1.71 f 103.8 b-e 2.14 c-e 2.92 a-c 5.06 de 42.19 ab p0k2 46.48ac 3.03 1.85 ef 104.2 b-e 2.45 b-e 3.28 a-c 5.73 b-e 43.05 ab p0k3 38.15bc 3.02 1.67 f 101.6 e 1.88 e 2.93 a-c 4.81 de 38.09 b p1k0 35.56bc 2.98 2.33 d 102.4 de 2.18 c-e 2.28 c 4.46 e 48.87 ab p1k1 54.8a-c 3.04 2.39 cd 105.8 a-d 2.74 a-e 3.16 a-c 5.90 b-e 46.57 ab p1k2 56.78ab 3.05 2.55 b-d 107.5 ab 3.09 a-d 4.02 a 7.12 ab 43.45 ab p1k3 52.1a-c 3.03 2.38 cd 105.3 b-e 2.33 c-e 2.41 c 4.74 de 48.50 ab p2k0 37.11bc 2.99 2.84 a-c 103.6 b-e 2.49 b-e 2.62 bc 5.11 de 48.67 ab p2k1 61.11 a 3.02 2.93 ab 106.8 a-c 3.13 a-c 3.39 a-c 6.52 a-d 47.90 ab p2k2 63.00 a 3.16 3.11 a 109.1 a 3.67 a 4.01 a 7.69 a 48.20 ab p2k3 43.3a-c 2.99 3.04 a 105.3 b-e 2.72 a-e 2.82 bc 5.54 b-e 49.38 a p3k0 38.33bc 2.92 2.23 de 102.4 de 1.97 e 2.78 bc 4.75 de 40.31 ab p3k1 47.0a-c 3.01 2.47 b-d 103.3 c-e 2.48 b-e 3.07 a-c 5.55 b-e 44.84 ab p3k2 49.4a-c 3.11 2.50 b-d 104.9 b-e 3.42 ab 3.56 ab 6.98 a-c 48.79 ab p3k3 37.89bc 2.98 2.32 d 104.0 b-e 2.08 de 3.13 a-c 5.21 c-e 39.58 ab se  6.66 ns 0.14 1.159 0.31 0.33 0.54 3.13 cv (%) 25.14 4.46 10.52 1.93 20.83 18.76 16.73 12.09 in a column means having similar letter (s) are statistically similar and those having dissimilar letter (s) differ significantly by dmrt at 0.05 level of probability p0: 0 kg tsp ha-1, p1: 100 kg tsp ha-1, p2: 175 kg tsp ha-1, p3: 250 kg tsp ha-1; k0: 0 kg mop, k1: 60 kg mop ha-1, k2: 120 kg mop ha-1, k3: 180 kg mop ha-1 similar findings were discussed by mengel and kirkby (1980) who clearly indicated that k is known as one of the nutrients which are closely involved in metabolic processes and improved yield. the highest yield (3.67 t ha-1) was recorded with the combination of 175 kg tsp ha-1 and 120 kg mop ha-1. these increased in seed yield was associated with more number of pods plant-1, seeds pod-1 and/or 1000-seed weight. 105 performance of soybean under different levels of phosphorus and potassium stover yield (t ha-1) there was a non-significant difference of stover yield of soybean with various p fertilizer levels. the present results corroborated with ali et al. (2013) who reported that p had nonsignificant effect on stover yield of soybean. however, stover yield varied significantly with application of different levels of k fertilizer. the maximum (3.72 t ha-1) stover yield was recorded from 120 mop ha-1. similar findings were observed by jahan et al. (2009). though, combined effect of p and k application had also significant effect on stover yield of soybean but the highest yield (4.02 t ha-1) was recorded from the combination of 100 and 120 kg ha-1 of tsp and mop, respectively. biological yield (t ha-1) of soybean biological yield of soybean varied significantly with different level of p and k application (table 2).the maximum biological yield of soybean (6.22 t ha-1) was recorded from 175 kg tsp ha-1 treatment; while, the maximum biological yield (6.88t ha-1) was recorded in 120 kg mop ha-1). finally, the highest biological yield (7.69 t ha-1) was recorded from the combination of 175 kg tsp ha-1 and 120 kg mop ha-1 . generally biological yield increased with the increasing doses of p and k fertilizer application along with other recommended applied fertilizer. these results are similar to findings of munir and mcneilly (1987) who reported that increasing rates of p and k increased the biological yield. harvest index (%) harvest index of soybean varied significantly with different level of p application but nonsignificant with different level of k application (table 2). the maximum hi of soybean (48.54%) was recorded from 175 kg ha-1 of tsp. the present result is consistent with the findings of malik et al. (2006) who found that hi varied significantly due to different levels of phosphorus. combined effect of p and k application had also significant effect on harvest index of soybean. the highest hi (49.38%) was recorded from the combination of 175 and 120 kg ha-1of tsp and mop, respectively. conclusion from the results of this experiment it may be concluded that the application of p and k fertilizers influenced nodule formation, yield attributes and seed yield of soybean. although p and k played an important role on the yield of soybean, the application of their excess amount however acted negatively. the application of 175 kg ha-1 tsp and 120 kg ha-1 mop was found to be the most appropriate levels of p and k for maximum productivity of soybean. references aise, d., s. erdal, a. hasan and m. ahment. 2011. effects of different water, phosphorus and magnesium doses on the quality and yield factors of soybean (glycine max l.) in harran plain conditions. int. j. phys. sci. 6(6): 1484-1495. ali, a., m. a. malik, r. ahmad and t. s. atif. 1996. response of mungbean to potassium fertilizer. pak. j. agric. sci. 33(1-4): 44-45. ali, r., m. a. kader, a. k. hasan, f. t. zohra and s. uddin. 2013. yield performance of soybean as influenced by phosphorus. j. agrofor. environ. 7(1): 45-48. 106 khanam et al. anonymous. 2009. bright prospect for soybean farming in bangladesh. available at: http://www.thedailystar.net/news-detail-114970. anonymus. 2004. manitoba soil fertility guidelines. potassium manitoba agriculture, food and rural initiatives. bari (bangladesh agricultural research institute). 2013. krishi projokti hatboi (in bangla) 6th ed. gazipur, bangladesh. pp. 269-271. available at: http://www.bari.gov.bd/ borges, r., and a. p. mallarino. 2003. broadcast and deep-band placement of phosphorus and potassium for soybean managed with ridge tillage. soil sci. soc. am. j. 67:1920-1927. chowdhury, m. m. u., i. s. m. farhad, s. k. bhowel, s.k. bowmik and a.k. choudhury. 2014. fertilizer management for maximizing soybean (glycine max l.) production in char lands of bangladesh. the agriculturists. 12(2): 98-102. daff. 2010. soybeans production guideline. department of agriculture, forestry and fisheries, rsa, dpp. available at: daff.gov.za. deshmukh, v. n., r. p. rangacharya, s. s. rewatkar and b. u. solanke. 1994. response of soybean to phosphorus and potassium application in vertisol. j. potash res. 10(4): 332337. devi, k. n., l. n. k. singh, t. s. devi, h. n. devi, t. b. singh, k. k. singh and w. m. singh. 2012. response of soybean [glycine max (l.) merrill] to sources and levels of phosphorus. j. agril. sci. 4 (6): 1916-9752. dixit, a. k., d. s. tomar, a. saxena and s. k. kaushik. 2011. assessment of potassium nutrition in soybean for higher sustainable yield in medium black soils of central india. int. potash inst. 26: 1-11. frg. 2012. fertilizer recommendation guide. bangladesh agricultural research council (barc), farmgate, dhaka-1215, bangladesh. p. 274. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research (2nd ed.). international rice research institute. jhon wiley and sons, inc. singapore. pp. 139-240. hernandez, m. and f. cuevas. 2003. the effect of inoculating with arbuscular mycorrhiza and brady rhizobium strains on soybean (glycine max (l.) merrill) crop development. cultivos tropicales. 24(2): 19-21. islam, m. k., m. a. a. mondal, m. a. mannaf, m. a. h. talukder and m. m. karim. 2004. effects of variety, inoculums and phosphorus on the performance of soybean breeder seed production center, agric. res. stat., debigonj, panchagar, bangladesh. pakistan j. biol. sci. 7(12): 2072-2077. jahan, s. a., m. a. alim, m. m. hasan, u. k. kabiraj and m. b. hossain. 2009. effect of potassium levels on the growth, yield and yield attributes of lentil. intl. j. sustain. crop prod. 4(6): 1-6. jones, g. d., j. a. lutz and t. j. smith. 1977. effects on phosphorus and potassium on soybean nodules and seed yield. agron. j. 69: 1003-1006. magen, h. 1997. ipi activity in india – summary report for 1993-1997: results from field experimentation and description of promotional activity, october 1997. international potash institute, pp 33. malik, m. a., m. a. cheema, h. z. khan and m. a. wahid. 2006. growth and yield response of soybean (glycine max l.) to seed inoculation and varying phosphorus levels. j. agric. res. 44(1): 47-53. 107 performance of soybean under different levels of phosphorus and potassium mengel, k. and e. a. kirkby. 1980. potassium in crop production. advances in agronomy. 33:59-110. munir, m. and t. mcneilly. 1987. dry matter accumulation, height and seed yield in spring and summer rape as affected by fertilizers and spacing. pakistan. j. agric. res. 8: 143-149. nziguheba, g., c. a. palm, r. j. buresh and p.c. smithson. 1998. soil phosphorus fractions and adsorption as affected by organic and inorganic sources. plant and soil. 198: 159168. pauline, m. m., b. o. o. john, j. o. o. jude, w. anthony and h. john. 2010. effect of phosphorus fertilizer rates on growth and yield of three soybean (glycine max) cultivars in limpopo province. afr. j. agric. res. 5(19): 2653-2660. quaiyum, a., s. g. nahar, m.r. ubaidullah, m. m. hasan and m. a. latif. 2015. analysis of assistance to edible oil manufacturing industry and examining export possibilities. bangladesh j. tariff trade. 1(2): 06-28. rahman, m. m., m. m. hossain, m. p. anwar and a. s. juraimi. 2011. plant density influence on yield and nutritional quality of soybean seed. asian j. plant sci. 10(2): 125-132. rotaru, v. 2010. the effect of phosphorus application on soybean plants under suboptimal moisture condition. inst. genetics plant physio. moldovan academy of sciences. republic of moldova. saic. 2007. saarc agricultural statistics of 2006-07. saarc agricultural information center, farmgate, dhaka-1215, bangladesh. p. 23. sardana, h. r. and s. verma. 1987. combined effect of insecticide and fertilizers on the growth and yield of mungbean (vigna radiata l wilczek). indian j. entom. 49(1): 64-68. shehu, h. e., j. d. kwari and m. k. sandabe. 2010. nitrogen, phosphorus and potassium nutrition of sesame (sesamum indicum) in mubi, nigeria. new york sci. j. 3(12): 21-27. silva, j. and j. s. bohnen. 1991. application of n, k and s and their relation with yield and level of n, no3 and k in seed of peas in the green house. soil fert. abst. 54: 3409. singh, v. j. and r. p. bajpai. 1990. effect of phosphorus and potash on the growth and yield of rainfed soybean. indian j. agron. 35(3): 310-311. tomar, s. s., r. singh and h. p. singh. 2004. response of phosphorus, sulphur and rhizobium inoculation on growth, yield and quality of soybean (glycine max. l.). progr. agric. 4(1): 72-73. tsvetkova, g. e. and g. i. georgiew. 2003. effect of phosphorus nutrition on the nodulation, nitrogen fixation and nutrient use efficiency of bradyrhizobium japonicum soybean (glycine max l.) symbiosis. bulg. j. plant physio. special issue: 331-335. turan, m., n. ataoglu and f. sahin. 2006. evaluation of the capacity of phosphate solubilizing bacteria and fungi on different forms of phosphorus in liquid culture. j. sustain. agri. 28:99-108. usherwood, n. r. 1998. nutrient management for top-profit soybeans. www.ppi-ppic.org. (verified 2/15/14). webb, j. r., a. p. mallarino and a. m. blackmer. 1992. effects of residual and annually applied phosphorus on soil test values and yields of corn and soybean. j. prod. agric. 5:148152. 108 khanam et al. xiang, d. b., t. w. yong, w. y. yang, y. wan, w. z. gong, l. cui and t. lei. 2012. effect of phosphorus and potassium nutrition on growth and yield of soybean in relay strip intercropping system. sci. res. essays. 7(3): 342-351. microsoft word 2. baj-216_revised.docx bangladesh agron. j. 2016, 19(1): 11-17 effect of genotype and density on the productivity of mungbean r. yeasmin1, m. a. karim1*, m.m. haque1 and m. a. b. mia2 1department of agronomy, 2department of crop botany bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh corresponding author: akarim1506@yahoo.com keywords: grain legume, spacing, yield, light interception abstract an investigation was carried out at the experimental field of the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur during september to november 2014 to evaluate the productivity of three mungbean genotypes, viz., gk-24 (g1), gk-63 (g2) and bu mug 4 (g3) under four plant spacing (densities) such as i) 15 cm x 10 cm= 66 plants m-2 (d1), ii) 20 cm x 10 cm= 50 plants m-2 (d2), iii) 25 cm x 10 cm= 40 plants m-2 (d3) and iv) 30 cm x 10 cm=33 plants m-2 (d4). the experiment was conducted in a factorial randomized complete block design with three replications. a wide variation among the genotypes was observed in relation to light transmission, yield, and yield contributing characters. at 30 cm x 10 cm spacing (d4) the highest light transmission ratio (ltr) was observed in g1 genotype (57.92) and the lowest ltr value in g2 genotype (46.92). among the three genotypes, g1 produced the highest seed yield (1094 kg ha-1). but highest seed number pod-1 was found in d2 (11.61) while maximum pods plant-1 (11.08) was in d4 treatment followed by d3 (10.59). among the four plant densities, treatment d3 showed the highest 1000-seed weight (50.30 g). the highest seed yield (1114 kg ha1) was recorded in the treatment d4. among the interaction, the highest number of seeds pod-1 (12.20) was found in the treatment d1g3, though the highest number of pods plant-1(12.03) was in treatment d4g1 but the1000-seed weight was the highest (51.92 g) in d3g1. the highest seed yield (1230 kg ha-1) was recorded from treatment d4g1. the result showed that gk 24 genotype performed the best in all respects of yield and yield attributes at 30 cm x 10 cm spacing compared to other treatments. introduction mungbean (vignaradiata l. wilczek), belongs to the family leguminosae, is an important pulse crop. it ranks fourth in production and first in respect of area of pulses cultivation in bangladesh (bbs, 2013). as a leguminous crop it fixes atmospheric nitrogen and improves soil productivity. the yield of such an important crop in the field is very low in comparison to its potential productivity due to adverse effect of environment as well as management factors. environment plays a vital role in mungbean productivity as reported by allard (1990) and eisemann, et al. (1990). mungbean is cultivated either in late winter in southern part or in summer season in most of the other parts of bangladesh. recently developed short duration mungbean varieties could be successfully cultivated in wheat-rice cropping system without affecting cropping pattern after harvesting of wheat and before the transplantation of rice. mungbean has been expanded to the southwestern districts of bangladesh, mostly in the aman rice – wheat – mungbean or aman rice – vegetables / potato – mungbean cropping 12 yeasmin et al. patterns and also mungbean in rice-rice or rice-wheat system in northern districts. plant density may vary with genotype, time of sowing, growing conditions and other environmental factors. the optimum plant population can be maintained by using adequate seed rate so obtaining high yields; optimum seed rate should be used. in bangladesh, planting density of 30 cm x 10 cm gave higher yield of mungbean than 20 cm x 20 cm or 40 cm x 30 cm planting density (sarkar et al., 2004). high variation in growth, phenology, yield attributes and grain yield among mungbean genotypes was observed by yimram et al. (2009). sultana (2014) noticed a significant variation in 1000-seed weight, growth duration and productivity of the genotypes. based on the yield performance and short growth duration of mungbean genotypes, some of them have been selected. however, their management options have to be identified before making them available for cultivation by the farmers. therefore, this study was planned to determine yield performance of three selected mungbean genotypes at different plant densities. materials and methods the experiment was carried out at the experimental field of bangabandhu sheikh mujibur rahman agricultural university, gazipur during september to november 2014. the experimental site is located at the centre of madhupur tract (24° 09 n latitude and 90° 26' e longitude) having an elevation of 8.2 m from sea level. the soil type of the experimental field belongs to the shallow red brown terrace type under salna series of madhupur tract of agro ecological zone (aez) 28. the experiment was carried out in a factorial rcbd design. the genotypes were: i) gk-24 (g1), ii) ii) gk-63 and iii) bu mug 4. and the density (spacing) were: i) 15 cm x 10 cm= 66 plants m-2 (d1), ii) 20 cm x 10 cm= 50 plants m-2 (d2) iii) 25 cm x 10 cm= 40 plants m-2 (d3), and iv) 30 cm x 10 cm=33 plants m-2 (d4). the unit plot size was 3m x 1m. at physiological maturity, dry pods were harvested at different days after sowing (das) for different genotypes. the harvesting was started from 63 das for g2 and continued up to 70 das for g3.data on different morphological parameters including seed yield and yield contributing characters were recorded following standard methods. light transmission ratio (ltr) was calculated by the following formula i ltr = -------- i0 where, i = light intensity at the bottom of the crop i0= light intensity at the top of crop results and discussion plant height at 15 cm x 10 cm spacing, genotype gk 24 and bu mug 4 were statistically similar in plant height (fig. 1). the longest plant was observed in g3 (56.90 cm), where gk 63 produced the shortest plant (47.62 cm). at 20 cm x 10 cm spacing, the highest plant height was observed in g3 (56.58 cm) and the lowest in g2 (42.67 cm). at 25 cm x 10 cm spacing, the tallest plant was observed in g3 and the shortest plant in g2 (46.82 cm). at 30 cm x 10 cm spacing, the highest plant height was observed in g1 (53.51 cm) and lowest in g2 (48.59 cm). plant height is an important morphological character of crop plant that showed positive correlation with seed yield of mungbean (rubio et al., 2004). 13 effect of genotype and density on the productivity of mungbean fig.1. variation in plant height of three mungbean genotypes grown at different plant spacing. g1: gk 24, g2: gk 63, g3: bu mug 4, d1:15 cm x 10 cm, d2: 20 cm x 10 cm, d3: 25cm x 10 cm and d4: 30 cm x 10 cm number of branch plant-1 the maximum number of branch plant-1 was found from the widest density d4, compared to closer one (fig. 2). the number of branch per plant was decreased with the increase of plant density in the order of 30>25>20>15 cm. gupta (1998) also found the similar type of findings in mustard. fig. 2. variation in branch no. plant-1 of three mungbean grown at different plant spacing. g1: gk 24, g2: gk 63, g3: bu mug 4, d1:15 cm x 10 cm, d2: 20 cm x 10 cm, d3: 25cm x 10 cm and d4: 30 cm x 10 cm light interception through canopy at 15 cm x 10 cm spacing, the light transmission ratio (ltr) was the highest (27.95) in gk 24 and the lowest (14.93) in bu mug 4. at 20 cm x 10 cm spacing, the highest ltr value 14 yeasmin et al. (37.93) was observed in g1, while the lowest (32.00) in g3. at 25 cm x 10 cm, highest ltr value (41.34) was observed in g1 and the lowest (36.14) in g3. at 30 cm x 10 cm spacing, the highest ltr value (57.92) in g1 genotype, while the lowest ltr value (46.42) was observed in g2 (fig. 3). it was obvious that with the decrease in plant population, the light transmission ratio was increased. at d4, plant density the mungbean plants received optimum light at the lower canopy probably due to optimum plant spacing and minimum mutual shading. fig. 3. variation in light transmission ration (ltr) of three mungbean genotypes rown at different plant spacing. g1: gk 24, g2: gk 63, g3: bu mug 4, d1:15 cm x 10 cm, d2: 20 cm x 10 cm, d3: 25cm x 10 cm and d4: 30 cm x 10 cm effect of genotypes on yield and yield components the genotypes showed variation in producing grain yield and yield contributing characters (table 1). the maximum number of seeds pod-1 (11.77) was in g3 followed by g1 (11.63) while g2 had the lowest seeds pod-1 (11.14). in case of no. of pods plant-1, g3 produced the highest (10.48) and g2 the lowest (9.24). 1000-seed weight was maximum (50.15 g) in g1 followed by g2 (49.48 g). among the three mungbean genotypes, g1 produced the maximum seed yield (1094 kg ha-1) followed by g3. the highest seed yield in g1 was mostly associated with 1000-seed weight and number of pods plant-1. g2 produced the lowest seed yield (945 kg ha-1), which was due to the lowest number of pods plant-1 and seeds pod-1. table 1. effect of genotypes on seed yield and yield contributing characters of mungbean genotypes genotype no. of seed pod-1 no. of pods plant-1 1000seed wt. (gm) seed yield (kg ha-1) 15 effect of genotype and density on the productivity of mungbean g1 11.63 10.48 50.15 1093.70 g2 11.14 9.24 49.48 944.90 g3 11.77 9.59 46.98 1031.80 cv (%) 3.81 9.90 3.20 2.68 lsd (0.05) 0.37 0.82 1.33 23.20 here, g1: gk 24, g2: gk 63 and g3: bu mug 4 effect of plant spacing on yield and yield components plant spacing did not affect significantly the number of seeds pod-1, though the maximum seed number pod-1 was found in d2 (11.61) followed by d3 (11.60), and the lowest number (11.31) in d4 treatment (table 2). no. of pods plant-1 was recorded maximum (11.08) in d4 treatment followed by d3 (10.59); while the lowest number of pods plant-1(7.88) in treatment d1. plant spacing also influenced significantly the 1000-seed weight of mungbean. the treatment d3 showed the highest 1000-seed weight (50.30 g), while d1 showed the lowest (46.13g). the maximum seed yield (1114 kg ha-1) was recorded in the treatment d4 followed by d3 (1059 kg ha-1) while seed yield lowest (931.9 kg ha-1) in d1 treatment. the highest seed yield in d3 treatment was attributed mostly due to the highest number of pods plant-1. probably the specific plant spacing ensured optimum natural resources for plant productivity and thus produced the highest seed yield per hectare. table 2. effect of density on seed yield and yield contributing characters of mungbean genotypes density no. of seed pod-1 no. of pods plant-1 1000seed wt. (gm) seed yield (kg ha-1) d1 11.52 7.88 46.13 931.90 d2 11.61 9.54 49.23 988.10 d3 11.60 10.59 50.30 1059.80 d4 11.31 11.08 49.82 1114.10 cv (%) 3.81 9.90 3.20 2.68 lsd (0.05) 0.43 0.95 1.53 26.79 d1:15 cm x 10 cm, d2: 20 cm x 10 cm, d3: 25cm x 10 cm and d4: 30 cm x 10 cm genotype and density interaction effects on yield and yield components interaction of mungbean genotypes and density influenced significantly on seed yield and yield contributing characters (table 3). the maximum number of seeds pod-1 (12.20) was found in the treatment d1g3, which was followed by d2g3 (12.10). the lowest number of seeds pod-1(10.60) was observed in the treatment d1g2. higher number of pods plant1(12.03) was recorded in treatment d4g1 followed by d3g1. contrary, the lowest number of pods plant-1(7.21) was recorded in the treatment d1g3. 1000-seed weight was significantly affected by the interaction of genotypes and plant spacing. the maximum 1000-seed weight (51.92 g) was recorded in the treatment d3g1, which was followed by d4g1 and d4g2. the minimum 1000-seed weight (45.36 g) was recorded in d1g3 treatment followed by d1g2 treatment. the highest seed yield (1230 kg ha-1) was recorded from d4g1, which was followed by d3g1 (1134 kg ha-1) while lowest seed yield was recorded from the d1g2 (859 kg ha-1) followed by the treatment d2g2. the highest seed yield in d4g1 was attributed due to combined effect of number of pods plant-1 and 1000-seed weight. 16 yeasmin et al. table 3. interaction effect of genotype and density on seed yield and yield contributing characters of mungbean genotypes interaction no. of seed pod-1 no. of pods plant-1 1000seed wt. (gm) seed yield (kg ha-1) d1g1 11.77 8.49 47.24 991.50 d1g2 10.60 7.93 45.79 859.10 d1g3 12.20 7.21 45.36 944.90 d2g1 11.50 10.22 49.92 1020.00 d2g2 11.23 8.65 49.87 921.40 d2g3 12.10 9.74 47.91 1022.90 d3g1 11.60 11.18 51.92 1133.50 d3g2 11.40 10.04 50.91 994.50 d3g3 11.80 10.54 48.06 1051.40 d4g1 11.63 12.03 51.51 1230.00 d4g2 11.33 10.33 51.36 1004.60 d4g3 10.97 10.87 46.58 1107.90 cv (%) 3.81 9.90 3.20 2.68 lsd (0.05) 0.74 1.64 2.65 46.39 g1: gk 24, g2: gk 63, g3: bu mug 4, d1:15 cm x 10 cm, d2: 20 cm x 10 cm, d3: 25cm x 10 cm and d4: 30 cm x 10 cm conclusion considering the results of this study it could be concluded that genotype, gk 24 yielded higher than gk 63 and bu mug4, but 30 cm x 10 cm spacing was found the most suitable one among the tested four spacing. overall, gk 24 genotype performed better in all respects of yield and yield attributes at 30 cm x 10 cm spacing. references allard, m. and m. a. q. sheikh. 1990. variability and correlation studies in summer mungbean (vigna radiata l.). bangladesh agric. 12: 63-67. bbs. 2013. statistical yearbook of bangladesh. bangladesh bureau of statistics. vol. 2, no. 2. eisemann, l. t. 1990. the physiological basis of crop yield. in: l. t. evans (ed.). crop physiology-some case histories. cambridge university press, cambridge. pp. 345. gupta, v. s. 1998. crop improvement.vol. 1. physiological attributes. oxford and ibh, new delhi. pp. 131-142. rubio, j., j. i. cubero, l. m. suso and f. flores. 2004. biplot analysis of trait relation of white lupin in spain. euphytica. 135: 217-224. sarkar, a. r., h. kabir, m. begum and a. salam, 2004. yield performance of mungbean as affected by planting date, variety and plant density. j. agron. 3: 18-24. sultana, s. 2014. genotype environment interaction in quality seed production of mungbean. m. s. thesis. seed science and technology unit, bsmrau. 17 effect of genotype and density on the productivity of mungbean yimram, t., p. somta and p. srinives. 2009. genetic variation in cultivated mungbean germplasm and its implication in breeding for high yield. field crops res. 112: 260-266. grain development of wheat in 2010-12 bangladesh agron. j. 2016, 19(2): 79-85 grain growth of wheat under prevailing air temperature m.a.k. mian1, m.r. islam2, j. hossain2 and m.a.aziz1 agronomy division, bari, joydebpur1 and rars, ishwardi2 bangladesh agricultural research institute, joydebpur, gazipur 1701 key words: phenological duration, grain growth, wheat, air temperature abstract an experiment was conducted at the regional agricultural research station, ishwardi, pabna in two consecutive years of 2010-2011 and 2011-2012 to quantify the effect of temperature on phenological duration and grain growth of wheat. temperature variation was created by changing sowing date (15 november=s1, 30 november=s2, 15 december=s3 and 30 december=s4). results revealed that reproductive phase was more sensitive to high temperature as compared to vegetative phase of wheat. reproductive phase reduced from 54 to 37 days in 2010-2011 and from 64 to 34 days in 2011-2012 as influenced by higher air temperature under late sowing. duration of reproductive phase was strongly and negatively correlated with mean air temperature (r=-0.64 to -0.96 at p<0.01). maximum grain growth (49.1250.18 mg grain-1) was recorded at 55 days after anthesis in 30 november sowing in both the years. grain growth was negatively correlated (r=-0.80 at p<0.01) with mean air temperature during grain growth period. grain yield was the highest (4560-6080 kg ha-1) in 30 november sowing, afterwards it reduced in both the years. grain yield was negatively correlated (r=-0.70 at p<0.01) with mean air temperature of grain growth period. rising of air temperature at grain filling stage subjected to reduced grain yield of wheat. effect of temperature on grain yield of wheat can be explained about 88% by the function of y= -14910+ 2069x-52.67x2 (r² = 0.88). rising of one degree (oc) temperature above optimum (19.64 0c) grain yield reduced @ 53 kg ha-1 (0.98%). introduction wheat is an important cereal crop in bangladesh covering an area of 436814 ha with an annual production of 1347926 metric tons (bbs, 2016). wheat is winter season crop in bangladesh. but winter is becoming shorter due to climate change and global warming. it is estimated that temperature would be increased about 1.4°c by 2050 and 2.4°c by 2100 in bangladesh (oecd, 2003). therefore, wheat production may be reduced. as the global warming, temperature has significant effect on crop production. due to global warming, environmental scientists have given research emphasis on temperature effect and other weather elements. bangladesh has experienced climate changed effect due to global warming (karim, 2015). winter is coming shorter and temperature is rising in winter affecting the winter crops in bangladesh (mian et al., 2016). wheat requires different temperatures at different stages of plant growth and development. the optimum temperature for wheat ranges from 20° to 25° c. temperature above 30 0c at grain filling stage leads the crop to forced maturity and retards grain formation resulting yield loss (uddin et al., 2015). rising of air temperature in later part of winter affects the grain development and reduces grain growth resulting lower yield of wheat (bari, 2016). sometimes, farmers cannot sow wheat timely due to excess soil moisture or standing crop of t. aman rice in the field. consequently, delay sowing of wheat frequently subjects to high 80 mian et al. temperature stress in grain filling stage. on this account, farmers harvest lower yield of wheat (bari, 2016). temperature is the single most important climatic factor that affects the growth and development of crop plant (mian et al., 2013). it also influences the other different physiological process of the crop plant. temperature affects root and shoot growth, nutrient uptake, water absorption, photosynthesis, respiration, transpiration, translocation of photosynthate and other metabolic functions in the plant system (ali and sarker, 2016). high temperature affects phenology, growth and yield of wheat (chakrabarti et al. 2013). different planting time and year to year temperature variation would affect the grain growth and grain yield of wheat. the present study was undertaken to quantify the effect of temperature on phenology and grain growth of wheat under late sown irrigated condition. materials and methods the experiment was conducted at the regional agricultural research station, ishurdi, pabna during the rabi season of 2010-2011 and 2011-2012. the experiment was laid out in a rcb design with four replications. unit plot size was 6 m × 5 m. soil texture of the experimental site was sandy loam. wheat var. bari gom-26 was used as test crop in the experiment. the treatment was 15 november= s1, 30 november= s2, 15 december= s3 and 30 december= s4. the crop was fertilized with 80-35-5520-1.2 kg ha−1 of n-p-k-s-b. all nutrients including 2/3 of n were applied as basal. rest of 1/3 of n was top dressed at cri stage. three irrigations were applied at cri, booting and grain filling stages. weed control was done at 25 days after emergence by spading in between rows. no disease and insect control is needed. data on duration of phenological phases, grain weight at 5 days interval starting from 20 days after anthesis, grain yield, and daily air temperature were recorded. air temperature was calculated on the basis average of daily maximum and minimum temperature. crop was harvested on 25 march, 1 april, 2 april and 4 april respectively in 2011 and on 15 march, 22 march, 28 march and 7 april, respectively in 2012. data were analyzed and presented in tables and figures. optimum temperature was estimated using the functional model as below (mian et al., 2011). y=a + bxcx2 y=grain yield of wheat (dependent variable) a=intercept (constant) x=mean air temperature (independent variable) b and c are the rates of change of grain yield due to change of air temperature optimum temperature for maximum grain yield of wheat (yw)= (-b)/2c results and discussion effect of sowing date and air temperature on phenological duration phenological duration is changed due to change of sowing date (table 1). duration of vegetative phase was found maximum (68 days) in 30 november sowing but minimum (34-37 days) in 30 december sowing in both the years. duration of reproductive was longer (54-64) in 15 november sowing; afterwards it decreased chronologically with the shortest (34-37 days) in 30 december sowing. field duration was exhibited higher (112-122 days) in earlier sowing as compared to later sowing. similar results also have been reported by ali and sarker (2016). phenological duration showed negative correlation with air temperature (table 2). duration of reproductive phase showed strong and negative correlation (r=-0.64 to -0.96 at p< 0.01) with air temperature in both the years. field duration also exhibited strong and negative correlation (r=-0.82 to -0.93 at p< 0.01) with air temperature in 2010-2011 and 2011-2012. correlation 81 grain growth of wheat under prevailing air temperature between duration of vegetative phase and air temperature was very weak but negative (table 2). the results are in agreement with the findings of others (wheeler et al., 1996 and mian et al., 2013). effect of sowing date and air temperature on grain growth effect of sowing date on grain growth has been presented in fig.1 and fig.2. sowing in 15-30 november exhibited higher trend of grain growth in both the years (fig. 1 and fig. 26) as compared to later sowing. grain growth was maximum (49.12-50.18 mg grain-1) in 30 november sowing followed by 15 november sowing while the lowest in 30 december sowing in both the years. grain growth showed negative and strong correlation (r=0.80 at p<0.01) with air temperature (table 2). the results indicated that grain growth reduced due to higher temperature in late sown condition of wheat. similar results also have been described by khan and aziz (2015), and (uddin et al., 2015). effect of sowing date and air temperature on grain yield grain yield was the highest (4560-6080 kg ha-1) in 30 november sowing and the lowest in 30 december sowing in both the years (table 4). the results expressed that grain yield reduced in later sowing as compared earlier sowing. grain yield showed negative and strong correlation (r= -0.71 to -0.79 at p<0.01) with air temperature (table 4). the results revealed that rising of air temperature at later sowing reduced grain growth resulting poorer grain yield of wheat. the results are in agreement with the reports of bari (2014) and bari (2016). effect of temperature on grain yield of wheat can be explained about 88% by the function of y=-14910+ 2069x -52.67x2 (r² = 0.88) (fig. 3). by using the function it was estimated that rising of one degree (oc) temperature above optimum (19.64 0c) grain yield reduced @ 53 kg ha-1 (0.98%). similar results also have been described by chakrabarti et al. (2013). conclusion reproductive phase as well as field duration of wheat would be reduced as influenced by air temperature at later sowing (after 30 november). grain growth was higher in 30 november sowing and it was negatively correlated (r=-0.80 at p<0.01) with mean air temperature. rising of one degree (oc) temperature above optimum (19.64 0c) grain yield would be reduced @ 53 kg ha-1 (0.98%). table 1. phenological duration of wheat under different sowing dates (2010-2011 and 2011-2012) year sowing date vegetative phase (days) reproductive phase (days) field duration (days) 2010-2011 15 november 58 54 112 30 november 68 45 113 15 december 63 39 102 30 december 56 37 93 2011-2012 15 november 56 64 122 30 november 68 45 114 15 december 65 38 105 30 december 64 34 98 mean 62 45 107 stdev 5 10 10 82 mian et al. table 2. effect of air temperature on phenological duration of wheat (2010-11and 2011-2012) year correlation between correlation co-efficient (r) 2010-2011 duration of vegetative phase and air temperature -0.26ns duration of reproductive phase and air temperature -0.96** field duration of and air temperature -0.93** 2011-2012 duration of vegetative phase and air temperature -0.14ns duration of reproductive phase and air temperature -0.64** field duration of and air temperature -0.82** ** indicates significant at 0.01 level of probability, ns = not significant table 3. effect of air temperature on grain growth of wheat (2010-2011 and 20112012) year sowing date air temperature 0c (reproductive phase) grain wt. (mg grain-1) correlation co-efficient (r) 2010-2011 15 november 18.60 48.22 -0.74** 30 november 22.86 50.18 15 december 24.09 42.57 30 december 25.14 39.21 2011-2012 15 november 20.16 47.50 -0.69** 30 november 23.17 49.12 15 december 24.42 42.45 30 december 26.42 39.24 mean 23.11 44.81 -0.80** std 2.59 4.46 combined of 2010-2011 and 20112012 ** indicates significant at 0.01 level of probability table 4. effect of air temperature on grain yield of wheat (2010-2011 and 20112012) year sowing date air temperature 0c (reproductive phase) grain yield (kg ha-1) correlation co-efficient (r) 2010-2011 15 november 18.60 5920 -0.79** 30 november 22.86 6080 83 grain growth of wheat under prevailing air temperature 15 december 24.09 4380 30 december 25.14 3580 2011-2012 15 november 20.16 4200 -0.71** 30 november 23.17 4560 15 december 24.42 4040 30 december 26.42 3000 mean 23.11 4470 -0.70** std 2.59 1064 combined of 2010-2011 and 20112012 ** indicates significant at 0.01 level of probability fig. 1. grain growth of wheat as affected by different dates of sowing (s1 =15 november, s2= 30 november, s3=15 december and s4=30 december) in 2010-2011 84 mian et al. fig. 2. grain growth of wheat as affected by different dates of sowing (s1 =15 november, s2= 30 november, s3=15 december and s4=30 december) in 2011-2012 fig. 3. functional relationship between air temperature and grain yield of wheat reference y = 14910+ 2069x -52.67x2 r² = 0.88 y ie ld (k g/ ha ) mean air temperature (oc) 85 grain growth of wheat under prevailing air temperature ali, m. z. and m. a. i. sarker. 2016. effect of sowing time based temperature variation on growth, yield and seed quality of gardenpea. in: unfavourable ecosystem. crop production under high temperature and drought stress. agronomy division, bangladesh agril. res. int. gazipur 1701. pp. 1-7. bari (bangladesh agricultural research institute). 2014. interaction effect of different locations, dates of sowing and genotypes on yield contributing characters and yield of wheat. in: annual report. wheat res. centre. bangladesh agril. res. int. nashipur, dinajpur. pp. 115-116. bari (bangladesh agricultural research institute). 2016. development of yield model of modern wheat varieties under late sown heat stress environment. in: annual report. wheat res. centre. bangladesh agril. res. int. nashipur, dinajpur. pp. 110-119. bbs (bangladesh bureu statistics). 2016. yearbook of agril. statistics-2015. bangladesh bur. stat. ministry of planning. govt. people’s republic of bangladesh. pp.7881. chakrabarti, b., s. d. singh, v. kumar, r. c. harit and s. misra. 2013. growth and yield response of wheat and chickpea crops under high temperature. indian j. plant physiol. 18: 7-14. karim, m. a. 2015. the challenge of increasing climate variability to climate smart agriculture in bangladesh. in: souvenir, 14th confer. bangladesh soci. agronomy. bangladesh agril. res. council. farmgate dhaka 1215. pp. 25-36. khan, m. s. a and m. a. aziz. 2015. impact of sowing date induced temperature and management practices on development events and yield of mustard. bangladesh agron. j. 18(2): 45-52. mian, m. a. k., m. r. islam, j. hossain, m. s. alam. 2011. estimation of nutrient level of mustard in charland. bangladesh agron. j. 14 (1-2): 27-32. mian, m. a. k., m. r. islam, j. hossain and m. s. alam. 2013. assessing agroclimatological model of summer mungbean. in: international confer. on crop management in changing climate. univ. faisalabad. pakistan. p. 135. mian, m. a. k., m. r. islam and j. hossain. 2016. sowing time and air temperature: a functional yield model of lentil. bull. inst. trop. agr. kyushu univ. 39: 53-64. oecd (the organization for economic co-operation and development). 2003. rising food prices: causes and consequences. 9 p. available online: http://www.oecd.org/dataoecd/54/42/ 40847088.pdf [accessed on the 20 january 2009]. uddin, r., m. s. islam, m. j. ullah, p. k. hore and s. k. paul. 2015. grain growth and yield of wheat as influenced by variety and sowing date. bangladesh agron. j. 18(2): 97-104 wheeler, t. r., t. d. hong, r. h. ellis, g. r. batts, j. i. l. morison and p. hadley. 1996. the duration and rate of grain growth, and harvest index, of wheat (triticum aestivum l.) in response to temperature and co2. j. exp. bot47: 623630. http://link.springer.com/article/10.1007/s40502-013-0002-6#author-details-1 http://link.springer.com/article/10.1007/s40502-013-0002-6#author-details-2 http://link.springer.com/article/10.1007/s40502-013-0002-6#author-details-3 http://link.springer.com/article/10.1007/s40502-013-0002-6#author-details-4 http://link.springer.com/article/10.1007/s40502-013-0002-6#author-details-5 86 mian et al. reference ali, m. z. and m. a. i. sarker. 2016. effect of sowing time based temperature variation on growth, yield and seed quality of gardenpea. in: unfavourable ecosystem. crop production under high temperature and drought stress. agronomy division, banglades... bari (bangladesh agricultural research institute). 2014. interaction effect of different locations, dates of sowing and genotypes on yield contributing characters and yield of wheat. in: annual report. wheat res. centre. bangladesh agril. res. int. na... bari (bangladesh agricultural research institute). 2016. development of yield model of modern wheat varieties under late sown heat stress environment. in: annual report. wheat res. centre. bangladesh agril. res. int. nashipur, dinajpur. pp. 110-119. bbs (bangladesh bureu statistics). 2016. yearbook of agril. statistics-2015. bangladesh bur. stat. ministry of planning. govt. people’s republic of bangladesh. pp.78-81. chakrabarti, b., s. d. singh, v. kumar, r. c. harit and s. misra. 2013. growth and yield response of wheat and chickpea crops under high temperature. indian j. plant physiol. 18: 7-14. 3 bangladesh agron. j. 2015, 18(1): 53-57 effect of drying method on quality of soybean seed m. r. ali1, m. m. rahman2, m. s. rahman3, m. m. hossain1 and m. asaduzzaman1 1regional agricultural research station, bari, jamalpur, 2professor, department of agronomy, bau, mymensingh, 3upazila agriculture officer, dae, gopalpur, tangail key words: soybean, seed moisture, drying condition, viability, germination index abstract the experiment was conducted at the seed laboratory, regional agricultural research station, bari, jamalpur in 2010 with a view to study the effect of drying method on soybean seed germination and seedling vigour. eight drying condition viz., i) cemented floor ii) tripale upon cemented floor iii) bamboo chatai upon cemented floor, iv) cloth upon cemented floor, v) earthen floor, vi) tripale upon earthen floor, vii) bamboo chatai upon earthen floor and viii) cloth upon earthen floor were included in the experimental treatment variables with three replications using a completely randomized design. seed moisture content (%), germination (%), germination index, and seedling dry weight (g) were recorded at 50, 100, 150 and 200 days after storage (das). the highest germination percentage, germination index and seedling dry matter was obtained from tripale over cemented floor followed by bamboo chatai over cemented floor, tripale over earthen floor and bamboo chatai over earthen floor. the lowest germination percentage, germination index and seedling dry matter was obtained from cemented floor. introduction soybean (glycine max [l.] is the world’s most important grain legume crop in terms of total production and international trade. soybean seed contains 36-47% protein and 15-25% oil, 20-26% carbohydrate (rahman, 2001). it is rich in calcium (208 mg 100-1 g), iron (11.5 mg 100-1 g), carotene (426.0µg 100-1 g), phosphorus and thiamine including vitamins a, b, c and d (alam and rahman, 2005). the demand of soybean is increasing for making different food products for human consumption as well as feed for poultry and fish in bangladesh. soybean meal is the most important and high valued ingredient for poultry and fish feed as it is the only vegetable protein with a near complete balance of essential amino acids needed in higher animal nutrition (hari, 2000). now-a-days the demand of soybean in the feed industry has been increased. the average yield of soybean in bangladesh is low, only 1. t ha-1 (bbs 2009). the area under the crop has been increased currently to around 0,000 ha which produced about 59,000 t (krishi projukti hatboi, 2014). but the climate and soil of bangladesh are congenial for soybean production and it can widely be grown across bangladesh. the farmers of noakhali and lakshmipur districts have now become very much interested in soybean cultivation (39,137 ha and production 53383 t) since the demand of soybean has been increased recently in the domestic market mainly as poultry feed (bbs 2009). but the shortage of quality seed supply in planting time is a major problem to the production and expansion of soybean. the seed available in the market is often of poor quality in respect of health, germination and vigor. this is because soybean seed loses its viability within a very short time in storage under ambient conditions (singh et al., 1989, woodruff, 1998). manipulation of storage environment could help to improve or maintain seed quality. the present study was 54 ali et al. therefore, undertaken with a view to find out the effect of different sun drying methods on soybean seed quality. materials and methods an experiment was conducted at seed laboratory of regional agricultural research station, jamalpur during the period from may to december 2010 with a view to study the effect of different sun drying methods on soybean seed quality. soybean var. shohag (pb1) collected from bangladesh agricultural research institute (bari), joydebpur, gazipur was sown at regional agricultural research station farm, jamalpur with proper agronomic management. the crop was harvested at full maturity. after proper processing and cleaning the seed was dried in the sun to about 8% seed moisture content (smc) following the condition specified viz., i) cemented floor ii) tripale upon cemented floor iii) bamboo chatai upon cemented floor, iv) cloth upon cemented floor, v) earthen floor, vi) tripale upon earthen floor, vii) bamboo chatai upon earthen floor and viii) cloth upon earthen floor. the experiment was arranged in a completely randomized design with three replicates. the seed was tested for different quality parameters at 50, 100, 150 and 200 days after storage (das). the seeds were kept in the polythene bag (0.05mm thickness) under ambient room condition (23-32 °c). the quality parameters tested were seed moisture content, germination percentage, germination index, and seedling dry matter. seed moisture content: moisture content of seed was measured using high constant temperature oven dry method following ista rules (ista, 2003). about 5-8g of soybean seeds were placed in an aluminum dish and dried in oven at 130°c for 2 hours (until constant weight achieved). after that the samples were cooled in a desecrator and weighed. germination percent: germination test of seed was done in the sand-petridis method using sterilized sand. randomly collected 50 seeds in three replicates per bag were used in the test. the sand was moistened to 60% water holding capacity before placing it on the petridish. seed germination was counted at 8 days after placing the seed. the number of normal seedlings, abnormal seedlings and dead seeds were recorded and germination percentage was counted as per ista rules (ista, 2003). germination index (gi): germination index of seed was estimated from counting of the number of germinating seed each day up to 8 days of setting the test using the formula given by association of official seed analysts (rahman et al., 2010). gi = countfinaltodays countfinalatseedlingofno countsttodays countstatseedlingofno . 1 1. seedling dry matter: the normal seedlings from each germination lot were collected, washed with running tap water and surface dried. the seedlings were then dried in the oven at 70°c for 72 hours (until constant weight reached) and the weight expressed seedling-1 basis. field emergence: at the end of the storage period (200 das), randomly selected 100 seeds from each seed lot in three replications were sown in the well prepared field. the number of seedlings emerged each day were counted up to 15 days after sowing. data analysis was done statistically and the means were compared by duncan’s multiple range test (gomez and gomez, 1984). 55 effect of drying method on quality of soybean seed results and discussion seed moisture content the effect of drying condition on moisture content of soybean seed at each of the observation dates during the storage period was statistically significant. it was found that the seed moisture content increased with the increases of storage period. the moisture content was higher for the cemented floor drying method than other drying method. the seed moisture content for cemented floor were 8.55, 9.10, 9.59 and 10.31%, respectively at 50, 100, 150 and 200 days after storage. those values on tripale over cemented floor were 8.05, 8.40, 8.62 and 9.02%, respectively and it was statistically lowest compared to other drying condition (table1). similar result was observed by nautiyal and joshi, 1991. table 1. effect of drying condition on moisture content of soybean seed at different days after storage in 2010 drying condition seed moisture content (%) 50 das 100 das 150 das 200 das cemented floor 8.55a 9.1a 9.59a 10.31a tripale over cemented floor 8.05c 8.4c 8.62b 9.02b bamboo chatai over cemented floor 8.15b 8.84b 9.45a 10.14a cloth over cemented floor 8.15b 8.93ab 9.56a 10.13a earthen floor 8.25b 8.82b 9.35a 10.22a tripale over earthen floor 8.25b 8.93ab 9.54a 10.28a bamboo chatai over earthen floor 8.11c 8.83b 9.46a 10.21a cloth over earthen floor 8.30ab 9.00ab 9.42a 10.19a cv (%) 4.17 7.33 6.47 5.26 das= days after storing, cv= coefficient of variance, in a column, figures having similar letter(s) do not differ significantly germination percentage the effect of drying condition on germination percentage of soybean seed was statistically significant at each of the observation dates during storage period. it was found that the germination percentage decreased with the length of storage period. the decrease was higher for cemented floor drying condition than other drying condition. the present study revealed that seeds dried on tripale over a cemented floor showed the highest germination performance while those seeds dried on cemented floor showed the lowest germination percentage. the germination percentage on tripale over cemented floor were 94.0, 90.0, 88.0 and 86.0%, respectively at 50, 100, 150 and 200 das and it was statistically similar with other drying method except cemented floor, on cloth over cemented floor and earthen floor drying condition while those values for cemented floor were 80.0, 74.0, 68.0 and 60.0%, respectively (table 2). this result is in agreement with the findings of bhatt (2004) who reported that soybean seed should not be spread on the cemented floor directly as the heat generated from the surface reduces the viability of the seed. field emergence the effect of drying condition on field emergence of soybean seed was statistically significant. the field emergence was evaluated at 200 das. the highest field emergence (84%) was obtained on tripale over cemented floor and it was statistically similar to drying on bamboo chatai over cemented floor, tripale over earthen floor and bamboo chatai over earthen floor, respectively. the lowest germination (56%) was recorded from cemented floor drying condition (table 2). 56 ali et al. table 2. effect of drying condition on germination of soybean seed at different days after storage in 2010 drying condition germination (%) field emergence at 200 das 50 das 100 das 150 das 200 das cemented floor 80c (61.30) 74c (57.29) 68c (53.71) 60d 48.99) 56d (46.75) tripale over cemented floor 94a (73.72) 90a (69.41) 88a (67.44) 86a (65.93) 84a (64.18) bamboo chatai over cemented floor 92ab (71.05) 90 a (69.27) 86a (65.93) 84ab (64.18) 82ab (62.62) cloth over cemented floor 90ab (69.27) 85b (65.02) 80b (61.21) 74c (57.29) 70c (54.83) earthen floor 88b (68.05) 84b (64.18) 80b (61.26) 78bc (60.08) 76bc (58.63) tripale over earthen floor 92ab (71.86) 90a (69.09) 86a (66.65) 82ab (62.62) 80ab (61.67) bamboo chatai over earthen floor 92ab (71.31) 90a (69.16) 84ab (64.18) 80bc (61.21) 78ab (59.89) cloth over earthen floor 90ab (69.60) 88a (67.44) 84ab (64.18) 80bc (61.21) 76bc (58.63) cv (%) 2.54 1.37 2.33 2.64 2.82 das= days after storing, cv= coefficient of variance, a figures in parenthesis indicates the arc sine transformed value, in a column, figures having similar letter(s) do not differ significantly germination index the effect of drying condition on germination index was statistically significant at each of the observation dates during the storage period in 2010. it was found that the germination index decreased with the length of storage period. the decrease was higher for cemented floor drying condition than other drying condition. the germination index of soybean seed drying on tripale over cemented floor were 28.84, 26.60, 24.65 and 21.76, respectively at 50, 100, 150 and 200 das and these values were the highest and statistically similar to other drying method except cemented floor, cloth over cemented floor and earthen floor drying condition while those values for cemented floor were 22.73, 20.80, 16.63 and 13.48, respectively (table 3). table 3. effect of drying condition on germination index of soybean seed at different das in 2010 drying method germination index 50 das 100 das 150 das 200 das cemented floor 22.73b 20.80c 16.63c 13.48c tripale over cemented floor 28.84a 26.60a 24.65a 21.76a bamboo chatai over cemented floor 28.41a 26.27a 24.41a 21.10a cloth over cemented floor 23.59b 21.06c 19.26bc 17.50b earthen floor 24.14b 22.68bc 20.95ab 18.05b tripale over earthen floor 28.37a 26.74a 24.01a 21.43a bamboo chatai over earthen floor 27.04a 25.14ab 24.02a 21.50a cloth over earthen floor 26.15a 24.81ab 22.03ab 19.71ab cv (%) 9.71 4.51 6.27 6.70 das= days after storing, cv= coefficient of variance, in a column, figures having similar letter(s) do not differ significantly 57 effect of drying method on quality of soybean seed seedling dry matter the effect of drying condition on seedling dry matter of soybean seedling was statistically significant at each of the observation dates during the storage period in 2010. it was found that the seedling dry matter decreased with the length of storage period. the decrease was higher for cemented floor drying condition than other drying conditions. the seedling dry matter of soybean drying on tripale over cemented floor were 0.118, 0.116, 0.115 and 0.114 g seedling-1, respectively at 50, 100, 150 and 200 das and it was statistically similar to other drying conditions except cemented floor, cloth over cemented floor, earthen floor, bamboo chatai over earthen floor and cloth over earthen floor drying condition while those values for cemented floor were 0.092, 0.090, 0.080 and 0.070 g seedling-1, respectively (table 4). table 4. effect of drying condition on dry matter of soybean seedling at different days after storage in 2010 drying condition seedling dry matter (g seedling-1) 50 das 100 das 150 das 200 das cemented floor 0.092c 0.090c 0.08c 0.070c tripale over cemented floor 0.118a 0.116a 0.115a 0.114a bamboo chatai over cemented floor 0.116a 0.115a 0.113a 0.112a cloth over cemented floor 0.105b 0.102b 0.095b 0.096b earthen floor 0.096c 0.095c 0.092b 0.092b tripale over earthen floor 0.116a 0.114a 0.111a 0.109a bamboo chatai over earthen floor 0.101b 0.100b 0.099b 0.097b cloth over earthen floor 0.103b 0.101b 0.096b 0.093b cv (%) 6.99 6.38 8.49 7.66 das= days after storing, cv= coefficient of variance, in a column, figures having similar letter(s) do not differ significantly conclusion the study concludes that soybean seeds could be sun dried on tripale upon a cemented floor to 8% smc (seed moisture content) for storing to maintain high seed quality. references gomez, k. a. and a.a. gomez. 1984. statistical procedures for agricultural research 2nd edn. john willy and sons., new york. pp. 97-111. hari b. k. 2004. biochemistry and molecular biology of soybean seed storage protein. j. new seeds. 2(3): 342-350. hossain m. 2007. effect of field environment on growth, seed yield and quality of soybean. ph. d thesis. dept. agron. bangladesh agril univ., mymensingh. pp. 108-115. ista, 2003. international rules for seed testing, 2003. zurich, switzerland, ista. krishi projukti hatboi. 2014. krishi projukti hatboi khondo-1 (6th edition). bangladesh agricultural research institute (bari), joydebpur, gazipur p. 264. nautiyal, p.c. and y. c. joshi. 1991. storage of rabi/summer groundnut (arachis hypogea l.) with calcium cloride for prolonged seed viability and vigour. trop. sci., 31: 21-26. singh, s. r., k. o. rachie and k. e. dashiell. 1989. groundnut for tropics: research, production and utilization. jhon wiley and sons. chichester, england. pp. 122-129. bangladesh agron. j. 2017, 20 (1): 57-65 suitability evaluation of crop manager for boro rice production m. m. alam1*, m. a. ali2, m. a. rahman2, m. s. hossain2 and m. s. rahman3 1department of agronomy, shahid akber ali science and technology college, thakurgaon. 2department of agronomy, hajee mohammad danesh science and technology university 3department of agricultural chemistry, hajee mohammad danesh science and technology university corresponding author, e-mail: sagor_hstu@yahoo.com key words: crop manager, fertilizers, variety, yield, boro season abstract the experiment was conducted at a farmer’s field, nashipur, dinajpur during the period from january to june, 2014 during the boro season. there were three fertilizer treatments: f1: fertilizer recommended by farmers practice (fp), f2: fertilizer recommended by nutrient management (nm) and f3: fertilizer recommended by srdi. the variety brri dhan28 was used as the test crop for the experiment. it may be concluded that nutrient management recommended fertilizer dose performed better than recommended fertilizer dose by srdi and farmers practiced. so, it may be inferred that increase the crop yield in boro season farmers could apply n, p, k and s at the rate of 238, 60, 60 and 20 kg ha-1, respectively as nutrient manager compared to that of recommended doze. introduction rice (oryza sativa l) is one of the most extensively cultivated cereal crops for more than 50% of the world`s population. it is the second highest consumed cereal in the world after wheat (kumari et al., 2014). among the rice growing countries, bangladesh ranks fourth in respect of both area and production in the world (bbs, 2015).rice is intensively cultivated in bangladesh covering about 74% of arable land (ais, 2001). in bangladesh, there are three rice growing seasons viz. aus, aman, and boro. bangladesh produced around 19.1 million tons of rice from boro, 13.02 million tons from aman and 2.6 million tons from aus in 2014-15 (bbs, 2015). rice production area is decreasing due to human population pressures. therefore, attempts should be made to increase the yield per unit area by proper nutrient management, which is the most effective means to achieve the goal. the use of fertilizer has been progressively increasing and this trend is likely to continue in future if the nation desires to produce more agricultural products to meet the increasing demand. the continuous and unbalanced use of the chemical fertilizers under intensive cropping systems has been considered to be the main cause for declining crop yield and environmental degradation. nitrogen, phosphorus, potassium, zinc and sulfur are nutrient elements most commonly applied by rice farmers. but these inorganic fertilizers do not usually match the requirement of crops. in general, farmers apply higher rates of nitrogen (n), phosphorus (p) and, potassium (k). this higher application of n, p and k is often responsible for low yields and poor crop quality because optimum application of n, p and k is beneficial on physiological and biochemical requirements in plant growth. for boro rice production, nitrogen is the key nutrient required in the largest quantities. rice plants require a large amount of nitrogen at the early and mid-tillering stage to maximize the number of panicles (datta, 1981). phosphorus is the second major nutrient for plants and adequate phosphorus enhances many mailto:sagor_hstu@yahoo.com 58 alam et al. aspects of plant physiology, including the fundamental processes of photosynthesis, n-fixation, flowering, fruiting and maturation (wilson et al., 1998). about 41% of the soils of bangladesh contained p below the critical level (portch and islam 1984). potassium is the third major nutrient for plant and is necessary for several basic physiological functions, such as synthesis of protein and starch, normal cell division and growth. sulphur plays a unique role in plant metabolism and its main function is constituent of amino acids, biotin, vit b, and coenzyme a. zinc is important for chlorophyll synthesis, auxin formation, activation of dehydrogenase enzyme, stabilization of ribosomal fractions of plants. nutrient deficiencies can be corrected by the judicious application of chemical fertilizers. farmers do not apply uniform fertilizers in all plots of a national map unit due to different productivity level, but they desire uniform yield from all plots. however, farmers have their own conceptions about soil fertility and considered the factors that favor crop performance, such as plot size, location, previous fertilizer use, weed infestation and pest infestation (saleque et al., 2008). in most cases farmers use excess and imbalance fertilizer doses thus soil fertility as well as soil quality are degrading significantly. on the other hand, sustainable farming systems require soil fertility status to be maintained at a level that supports satisfactory plant growth while minimizing nutrient loss to the environment (betteridge et al., 2008).nutrient manager for rice is a computer-based decision support tool, enabling the rapid development of fertilizer guidelines for specific rice fields. it contains questions, which can be quickly answered with existing knowledge of farmers and technicians. after answering the questions, a printable fertilizer guideline is provided. the present investigation was, therefore, undertaken to evaluate the performance of nutrient manager on the yield and yield contributing characters of boro rice. materials and methods the experiment was conducted at a farmer’s field, nashipur, dinajpur during the period from january to june, 2014 during the boro season. the experimental field is a medium high land having sandy loam soil with ph 5.97. there were three fertilizer treatments: f1: farmers practice (fp), f2: fertilizer recommended by nutrient manager (nm) by fertilizer (238-60-6020 n p k s kg ha-1) and f3: fertilizer recommended by srdi (304, 39, 102, 86 and 4 n p k s kg ha-1. the variety brri dhan28 was used as the test crop. the experiment was laid out in a randomized complete block design (rcbd) with four (4) replications. all the treatments were randomly allocated to the experimental plots within each block. layout of the experiment was done maintaining plot to plot distance 75 cm and replication to replication distance 1.0 m. the total numbers of plots were 12 and the size of unit plot was 10 m2 (4.0 m x 2.5 m). rice seedlings were transplanted at 35 days after sowing with a spacing of 25 cm x 15 cm at two seedlings hill-1 on 13 february 2014. various intercultural operations were done for maintaining the normal growth and development of the crop. harvest maturity of the rice field was determined when 90% of the grains became golden yellow in color. five hills (excluding border hills) were selected randomly from each unit plot and collected by uprooting prior to harvesting for recording data on yield components and yield. the grain yields were recorded from each plot and moisture percentage reading was taken by moisture meter and grain weight was adjusted at 14% moisture. data were statistically analyzed and the significance of mean differences was adjudged by the duncan's multiple range test (dmrt) with the help of a computer package (mstatc) program (gomez and gomez, 1984). 59 suitability evaluation of crop manager for boro rice production results and discussion plant height: the results showed that plant height of brri dhan28 was not significantly affected by the different treatments (table 1). plant height varied from 89.50 cm in f3 treatment to 93.50 cm in f2 treatment. the tallest plant (93.50 cm) was recorded in the treatment f2 (recommended by nm) and the shortest plant (89.50 cm) was obtained in the treatment f3 (recommended by srdi). it might be due to smaller increase of all the fertilizers, which did not affect the growth and development of plants remarkably. number of total tillers hill-1: it was observed that the number of total tillers was significantly influenced by different fertilizer treatments at 1% level of probability (table 1). the highest number of total tillers hill-1 (18.50) was produced by the fertilizer dose recommended by nutrient manager (nm) which was followed by the fertilizer dose recommended by farmers practice (17.50) and the lowest number of total tillers hill-1(14.75) was found from the fertilizer dose recommended by srdi. these results are well supported with the findings of parvez et al. (2008) who found increased number of total tillers hill-1 with the increased use of fertilizers. number of effective tillers hill-1: there was a significant effect of different fertilizer treatments on the production of effective tillers hill-1 of rice plants (table 1). the number of tillers hill-1 due to different treatments varied from 13.38 to 17.13. the highest number of effective tillers hill-1 (17.13) was found in the treatment f2 (recommended by nm) which was statistically similar to the treatment f1 (recommended by fp). it might be due to smaller change of all the fertilizers from recommended rates. the minimum number of tillers hill-1 (13.38) was found in the treatment f3 (recommended by srdi). similar results were also obtained by balakrisnan and natarajaratnan (1986). panicle length: the length of panicle of brri dhan28 was significantly influenced by the application of fertilizers at 1% level of probability (table 1). the highest panicle length (27.25 cm) was found in f2 (recommended by nm). the lowest panicle length (22.13 cm) was observed in the treatment f3 (recommended by srdi) which was statistically similar to the treatment f1 (recommended by fp). these results are in agreement with rahman et al. (2009) who found increased panicle length with the application of different fertilizer dozes. number of total spikelets panicle-1: result showed that number of total spikelets panicle-1 of brri dhan28 responded significantly to different fertilizer treatments (table 1). the total number of spikelets panicle-1 varied from 122.50 to 141.00. the highest number of spikelets panicle-1 (141.00) was obtained from the treatment f2 (recommended by nm) which was statistically similar with respect to spikelets panicle-1 to the treatment f1 (recommended by fp). the lowest number of spikelets panicle-1 (122.50) was obtained from the treatment f3 (recommended by srdi). these results were supported by the findings of mondal et al. (1990) and halder et al. (2000). number of filled grains panicle-1: results presented in the table 1 showed a significant effect of various rates fertilizer supplied from respective fertilizers on the number of filled grains panicle-1 of rrri dhan28. the number of filled grains panicle-1 of different treatments ranged from 109.75 to 127.50. the highest number of filled grains panicle-1 (127.50) was found in the treatment f2 (recommended by nm) which was statistically similar to the treatments f1 (recommended by fp). it might be due to smaller reduction of all the fertilizers from 60 alam et al. recommended rates, which did not affect the growth and development of plants remarkably. the lowest number of filled grains panicle-1 (109.75) was found in the treatment f3 (recommended by srdi). these results support the findings of rahman et al. (2009) who found increased number of filled grains panicle-1. number of sterile spikelets panicle-1: the variation in the number of sterile spikelets panicle-1 due to different fertilizer treatments was significant at 5% level of significance (table 1). the results indicated that the number of sterile spikelets panicle-1 varied from 12.50 to 17.25. the highest number of sterile spikelets panicle-1 (17.25) was produced by the treatments f1 (recommended by fp). the lowest number of sterile spikelets panicle-1 (12.50) was produced by the treatment f3 (recommended by srdi) which was statistically similar to the treatments f2 (recommended by nm). weight of 1000 grains (g): it was observed that 1000 grain weight of brri dhan28 was significantly influenced (p < 0.01) by the application of different fertilizer levels. the 1000-grain weight ranged from 22.42 g to 23.72 g. the highest 1000-grain weight (23.72 g) was recorded from the treatments f2 (recommended by nm) which was statistically similar to the treatments f1 (recommended by fp) while the lowest 1000-grain weight (22.42 g) was obtained in the treatment f3 (recommended by srdi). similar results were reported by rahman et al. (2009) and parvez et al. (2008). moisture content (%): the moisture content of brri dhan28 was not changed by the different fertilizer doses. the moisture content ranged from 22.22% to 23.30%. the highest moisture content (23.30%) was obtained by the treatments f3 (recommended by srdi) and the lowest moisture content (22.22%) was produced by the treatment treatments f2 (recommended by nm). grain yield (tha-1): results showed that the grain yield of brri dhan28 responded significantly to the different fertilizer treatments (table 1). the grain yield due to various treatments ranged from 6.10 to 7.52 t ha-1. the highest grain yield (7.52 t ha-1) was obtained in the treatments f2 (recommended by nm). it might be due to higher number of tillers as well as panicles hill-1, higher number of grain per panicle, highest thousand grain-weight and higher harvest index in compared to that of f1 and f3 treatments. the lowest grain yield (6.10 t ha-1) was obtained in the treatments f3 (recommended by srdi) which was statistically similar to the treatments f1 (recommended by fp). it was due to the lowest number of tillers as well as panicles per hill and lowest number of grains per panicle. khan et al. (2007) reported that grain yield was significantly increased due to application of different chemical fertilizers. these results are also in agreement with the findings of rani et al. (2001), rahman et al. (2009) and parvez et al. (2008). straw yield (tha-1): straw yields varied significantly with different treatments. the yields of straw ranged from 10.00 to 11.02 t ha-1 (table 1). the highest straw yield (11.02 t ha-1) was obtained from the treatment f2 (recommended by nm) and the lowest value (10.00 t ha-1) with treatment f3 (recommended by srdi) which was statistically similar to the treatment f1 (recommended by fp). the treatments may be ranked in the order of f2>f1>f3 in terms of straw yield. rahman et al. (2009) reported that the application of urea-n in combination with other chemical fertilizers increased the straw yields of rice. 61 suitability evaluation of crop manager for boro rice production biological yield: the biological yield obtained from different treatments ranged from 16.10 to 18.54 t ha-1. the highest biological yield (18.54 t ha-1) was recorded in the treatments f2 (recommended by nm) which was statistically similar to the treatments f1 (recommended by fp). the lowest biological yield (16.10 t ha-1) was obtained in the treatments f3 (recommended by srdi) which was statistically similar to the treatments f1 (recommended by fp). this result was in agreement with rahman et al. (2009). harvest index (%): harvest index of brri dhan28 was significantly influenced by the different fertilizer levels (table 1). the highest harvest index (40.56%) was obtained from the treatments f2 (recommended by nm) and the lowest harvest index (37.89%) was obtained in the treatments f3 (recommended by srdi). nutrient content in rice grain and straw: the n content in rice grain and straw was significantly influenced by the application of various rates of fertilizers (fig.1).the highest n content in grain (1.392%) and straw (0.845% ) was observed in the treatments f2 (recommended by nm) and the lowest n content of grain (1.301%) and straw (0.721% ) was noted in the treatments f3 (recommended by srdi).the results revealed that n content in rice grain was higher than that of straw. a significant increase in n content in rice grain and straw due to the application of fertilizers has been reported by many investigators (bhaskaram and krisna, 2009). results in fig. 2 indicated that phosphorus content in the grain of brri dhan28 varied significantly due to different fertilizer treatments. the highest p content in grain (0.273%) and straw ((0.128%)) was found in f2 (recommended by nm) and the lowest value (0.222%) and (0.097%) in grain and straw was noted in the treatments f1 (recommended by fp). application of different fertilizer doses showed more pronounced effect in increasing the p content in rice grain and straw. an increase in p content both in rice grain and straw due to the application chemical fertilizers was reported by many investigators (parvez et al., 2008). similar results were also obtained by kadu et al. (1991). the potassium content both in grain and straw of brri dhan28 was significantly influenced due to application of various level fertilizers (fig.3). the highest k content in rice grain (0.284%) and straw (0.502%) were recorded in the treatment f2 (recommended by nm) and the lowest k content in grain (0.258%) and straw (0.395%) was recorded in the treatments f3 (recommended by srdi). the k content in straw was much higher than that in grain. these results are in agreement with singh et al. (2001) who revealed that k content in grain and straw was increased due to application of different chemical fertilizers. the results were also in agreement with the findings of bahmaniar and mashaee (2010). the sulphur content both in grain and straw of brri dhan28 was significantly influenced by the combined use of different dose fertilizers (fig.4). the highest s content of grain (0.171%) and straw (0.089%) was obtained in the treatments f2 (recommended by nm) and the lowest value of grain (0.148%) and straw (0.077 %) was noted in the treatments f3 (recommended by srdi). chandel et al. (2003) reported that application of sulphur from inorganic fertilizers increased the s content both in grain and straw of rice. conclusion from the above findings it may be concluded that nutrient manager fertilizer dose performed better than recommended fertilizer dose by srdi and farmers practiced.. so, it may be inferred that increase the crop yield in boro season then apply n, p, k and s at the rate of 238 kg, 60 kg, 60 kg and 20 kg ha-1, respectively compared to that of recommended doze. 62 alam et al. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 f1 = recommended by farmers practice f2 = recommended by nutrient manager f3 = recommended by srdi n it r o g e n % grain straw 0 0.1 0.2 0.3 f1 = recommended by farmers practice f2 = recommended by nutrient manager f3 = recommended by srdi p h o sp h o r u s % table 1. effects of different rates of fertilizer on the yield contributing characters and yield of rice var. brri dhan28 treatment plant height (cm) effective tillers hill-1 panicle length (cm) total spikelets panicle-1 (no.) filled grains panicle-1 (no.) sterile spikelets panicle-1 (no.) 1000 grain weight (g) grain yield (tha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) f1 = farmers practice 90.50 16.25a 23.13b 130.75ab 112.00ab 17.25a 23.20a 6.82b 10.75ab 17.57ab 38.82b f2 = nutrient manager 93.50 17.13a 27.25a 141.00a 127.50a 13.50b 23.72a 7.52a 11.02a 18.54a 40.56a f3 = srdi 89.50 13.38b 22.13b 122.50b 109.75b 12.50b 22.42b 6.10b 10.00b 16.10b 37.89c cv (%) 3.58 7.58 7.55 5.01 7.90 21.90 1.88 3.66 6.45 5.04 3.46 in a column, the treatment means having similar letter(s) do not differ significantly by dmrt fig. 1. effects of different rates of fertilizer on n content fig. 2. effects of different rates of fertilizer on p content in grain and straw of rice var. brri dhan28 in grain and straw of rice var. brri dhan28 63 suitability evaluation of crop manager for boro rice production 0 0.1 0.2 f1 = recommended by farmers practice f2 = recommended by nutrient manager f3 = recommended by srdi s u lp h u r % fig. 2. effects of different rates of fertilizer on k content fig. 2. effects of different rates of fertilizer on s content in grain and straw of var. brri dhan28 in grain and straw of var. brri dhan28 64 alam et al. references ais. 2001.krishi diary. agricultural information service, khamarbari, new airport road, farmgate, dhaka, bangladesh. pp. 20-22. bahmaniar, m. a. and mashaee, s. s. 2010. influences of nitrogen and potassium top dressing on yield and yield component as well as their accumulation in rice. african j. biotech. 9 (18): 2648-2653. balakrishnan, k. and natarajaratnan, n. 1986. effect of zn supplement on yield and components in certain rice varieties. madras agric. j. 73 (10): 598-600. bbs, (bangladesh bureau of statistics). 2015. estimates of boro rice (husked), 2014-15. pp. 1-6. betteridge, k., schnug, e. and haneklaus, s. 2008. will site specific nutrient management live up to expectation? agric. forestry res. 4(58): 283–294. bhaskaram, u. and krisna, d. 2009.effect of organic farming on soil fertility, yield and quality of crops in the tropics. 16th international plant nutrition colloquium 2009, sacramento, california, p. 89-90. chandel, r. s., singh, k., singh, a. k. and sudhakar, p. c. 2003. effect of sulphur nutrition in rice (oriza sativa l.) and mustard (brassica junceal. czern and coss) grown in sequence. indian physiol. 8(2): 155-159. datta, s. k. 1981. principles and practices of rice production. international rice research institute. los banos, philippines. p 349. gomez, k. a. and gomez, a.a. 1984.statistical procedure for agricultural research. intl. rice res. inst. john wiley and sons, new york. pp. 139-240. halder, k. p., chowdhury, m. j. u. and ahmed, n. 2000.effect of planting methods and nitrogen rates on the yield and yield components of ausrice grown under rained condition at the coastal area of bangladesh.bangladesh j. argil. sci. 27 (1): 59-64. kadu, p. b., bhoyar, v. s. and thakare, r. s. 1991. effect of npk-fym blended manurial mixtures on performance of rice. j. soil crop. 1 (2): 172-174. khan, m. u., qasim, m. and khan, i. u. qasim, m. and khan, i. u. 2007.effect of integrated nutrient management on crop yields in rice-wheat cropping system.sarhad.j. of agril. 23 (4): 1019-1025. kumari, p., g. c. mishra, a. k. pant, g. shukla and s. n. kujur.2014. comparison of forecasting ability of different statistical models for productivity of rice (oryza sativa l.) in india.the ecoscan. 8(3-4): 193-198. mondal, s. s., joyaram, d. and pradhan, b. k. 1990.effect of fertilizer and farmyard manure on the yield components of rice (oryza sativa l.). environ. eco. 8 (1): 223-226. parvez, m. s., islam m. r., begum, m. s., rahman, m. s. and abedin miah, m. j. 2008.integrated use of manure and fertilizers for maximizing the yield of brri dhan30. j. bangladesh soc. agric. sci. technol., 5(1&2): 257-260. portch, s. and islam, m. s. 1984 nutrient status of some of the more important agricultural soils of bangladesh. in “proceedings of international symposium on soil test crop response studies”, bangladesh agricultural research council and soil science society of bangladesh, pp. 97-106. 65 suitability evaluation of crop manager for boro rice production rahman, m. s. islam, m. r. rahman, m. m. and hossain, m. i. 2009. effect of cowdung, poultry manure and urea-n on the yield and nutrient uptake of bbri dhan29.bangladesh res. pub. j. 2(2): 552-558. rani, r., srivastava, o. p and rani, r. 2001.effect of integration of organics with fertilizer n on rice and n uptake.fertilizer news. 46(9): 63-65. saleque m. a., uddin m. k., ferdous a. k. m and rashid m. h. 2008.use of farmers’ empirical knowledge to delineate soil fertility-management zones and improved nutrient-management for lowland rice.commu. soil sci. plant anal, 39:25–45. wilson c. e., bollich p. k. and norman, r. j. 1998. nitrogen application timing effects on nitrogen efficiency of dry-seeded rice. soil sci. soc. am. j. 62: 959-964. bangladesh agron. j. 2016, 19(2): 71-77 effect of low cost drip tape irrigation system on yield and economics of sweet corn h. a. archana1*, n. asoka raja2, r. mahesh3 and r. kalpana4 * department of agronomy, tamil nadu agricultural university, coimbatore, 641003, tamil nadu, india *corresponding author: nancyarchu@gmail.com keywords: drip tape, sweet corn, pan evaporation, yield abstract a study was conducted to determine the effect of low cost drip tape irrigation system on yield and economics of sweet corn in comparison to conventional inline drip irrigation and surface irrigation systems during 2013-14 at coimbatore, india. the treatment comprises of two drip irrigation systems with three irrigation levels viz., 75, 100 and 125% of pan evaporation (pe) from class a pan evaporimeter. plant height, fresh cob length, girth, number of kernels per cob and single fresh cob weight and yield were higher at 125% pe in conventional in line drip irrigation system and it was statistically at par with drip irrigation at 125% pe in low cost drip tape irrigation system. water saving was 36, 49 and 62% at 125, 100 and 75% pe, respectively under conventional in line drip irrigation system and drip tape irrigation system as against the surface irrigation. the cost of low cost drip tape system was 68% lower than the conventional inline drip system. the results of the research indicated that based on net income, b:c ratio and gm/tmv ratio, adoption of low cost drip tape irrigation system at 125% pe was found to be best for small and marginal farmers with substantial yield and income compared to conventional inline drip system. introduction sweet corn is cultivated as a popular vegetable and ranks second in farm values and fourth in commercial values among all commercial crops in india. the productivity potential of sweet corn is higher than that of wheat and nutritive value is superior to rice on account of which it will no longer be considered a ‘coarse grain’ but a ‘nutritious grain’ (batra, 2002). technological innovations are to be exploited to achieve the objective of higher productivity and better water use efficiency. it is possible to achieve optimum quality and quantity of crop production per unit area if a proper irrigation method is applied along with other agronomic practices. adoption of modern irrigation techniques need to be emphasized to increase water use efficiency. drip irrigation is the most effective way to convey water and nutrients directly to plants and not only save water but also increases yields of vegetable crops (tiwari et al., 2003). because drip irrigation is capable of applying small amounts of water where it is needed and to apply it with a high degree of uniformity and frequently, these features make it potentially much more efficient than other irrigation methods (el-hendawy et al., 2008). adoption of drip irrigation might help in raising the irrigated area, productivity of crops and water use efficiency (sivanappan, 2004). drip irrigation has the potential for improving two of the most common contributing factors to n leaching (i.e) over fertilization and over irrigation. irrigation application can be reduced by 50 to 80 % with drip irrigation compared to surface and overhead sprinkler irrigation (locascio et al., 1989). mailto:nancyarchu@gmail.com 72 archana et al. the development of low-cost drip tape irrigation system, an irrigation method that is suited for small fields, would help in saving irrigation water over conventional drip systems. therefore this study was undertaken to find out the efficient drip irrigation system at an affordable cost for higher yield and economics of sweetcorn. materials and methods this study was conducted during 2013-14 at farmer’s field, pudhupalayam, tamil nadu, india. the experimental field is located at coimbatore (altitude: 426.7 m: 11°83' n and 76°71’e) in the western zone of tamil nadu. the texture of the experimental field was sandy clay loam. field capacity of the soil was 23.15% (dry basis), permanent wilting point was 11.73% and bulk density of the soil was 1.61 g/cm3. the air temperatures were all above 19°c while the relative humidity was below 91% during experiment period. fig 1. layout of the experimental field the quantity of water applied once in two days through drip was calculated by using the following formula; volume of irrigation (v) = (2 days cpe × kp × kc × wp × a) er where, v is the volume of water required in litres, cpe is the cumulative pan evaporation for two days (mm), kp is the pan factor (0.8), kc is the crop factors, a is the area (m2), wp is the wetted percentage (80%), er is the effective rainfall (mm). hybrid sweet corn variety (zea mays l. saccharata), sugar 75, was used as the test crop. the experiment was laid out in a randomized block design with three replications. the treatment comprises of two drip irrigation systems with three irrigation levels viz., 75, 100 and 125% of evaporation from a class a pan evaporimeter. the treatments were t1, t2 and t3drip irrigation at 125, 100 and 75% pe with drip tape system, respectively and t4, t5 and t6drip irrigation at 73 effect of low cost drip tape irrigation system on yield and economics of sweet corn 125,100 and 75% pe with conventional inline drip system, respectively and t7 surface irrigation (5 cm depth) at 0.8 iw/cpe ratio. the experimental field was thoroughly ploughed using tractor drawn tiller and then properly leveled. after leveling the field ridges and furrows were formed 75 cm apart to accommodate surface irrigated (furrow) crop. broad beds were formed in the dimension of 120 cm width, 30 cm furrow and 15 cm height. buffer channels were formed to control the lateral seepage of water from one plot to another plot. the plot size was 6 m × 3.6 m (fig. 1.). the water source from bore well was pumped through 7.5 hp motor and it was conveyed to the main field using 63 mm od pvc pipes after filtering through disc filter. from the main line, sub mains of 40 mm diameter pvc pipes were connected. drip tape lateral of 16 mm od (250 micron wall thickness of seamless tube) was fixed in the sub mains with a lateral spacing of 150 cm. similar to drip tape, conventional in line drip system was laid at 150 cm spacing. one lateral was placed in every paired row. the conventional in line drip lateral has 40 cm emitter spacing with 4 lph discharge, whereas, drip tape lateral had emitting point spaced 45 cm apart with a discharge rate of 8 litre per hour (lph) at 1 kg cm-2. flow from sub main to laterals was regulated with a provision of 16 mm tap in order to regulate the irrigation scheduling and the laterals were closed with end cap. after installation trial run was conducted to assess the uniformity coefficient of the system. crop factor (kc) for various growth stages of sweet corn crop stage duration (days) kc value initial 20 0.40 crop development 30 0.80 mid season 40 1.15 late season 10 0.70 (fao, 1991) the total water use inclusive of effective rainfall in furrow irrigation was 429 mm whereas it was 274 mm at 125% pe, 220 mm at 100% pe and 165 mm at 75% pe under both conventional in line as well as drip tape system. the data obtained from the experiments were analysed with anova and lsd tests using agres statistical analysis software package. results and discussion number of kernels green cob-1 (50.00 and 48.84%) was higher in both conventional drip system and drip tape system over surface irrigation. brahma bhatt (2012) stated that the marked improvement in yield attributes could be ascribed to overall improvement in vigour and crop growth, as reflected by improved dry matter accumulation, cgr, lai and stem diameter. any stress imposed during this period greatly affects kernel set. andrade et al. (1999) demonstrated that a limited partitioning of dry matter to reproductive tissues during the critical period (silking) results in low numbers of kernel set. green cob yield of 19.88 t ha-1 was observed higher in irrigation at 125% pe with conventional inline drip system (t4) which was comparable to irrigation at 125% pe with drip tape system (t1) (19.74 t ha -1) followed by drip irrigation at 100% pe in both conventional inline drip irrigation (t5) (17.68 t ha -1) and drip tape system (t2) (17.21 t ha-1). significantly lower green cob yield was recorded in surface irrigation at 5 cm depth with 0.8 iw/cpe ratio (t7) (13.56 t ha -1) (table 1.). this was in concordance with findings of bozkurt et al. (2011) showing that the corn grain yield 74 archana et al. was significantly increased by the irrigation level. highest yield, averaging 10.4 t ha-1 was registered under drip irrigation at 120 % of evaporation from a class a pan. karam et al. (2003) reported that grain yield was reduced by 37 % under water stress conditions. this reduction was due to a decline of 18 % kernel weight and 10 % in kernel number as a response to water deficit. drip irrigation scheduled at 125 % pe registered significantly higher green fodder yield in both conventional inline drip system (22.93 t ha-1) and drip tape system (22.58 t ha-1), which was 32.54 and 30.52 % more than surface irrigation, respectively. the increase in green fodder yield was mainly due to significant increase in dry matter accumulation in leaf and stem and total dry matter production of plant. the present findings are in accordance with viswanatha et al. (2000), who reported the maximum stover yield by drip irrigation scheduled at 0.8 epan over 0.4 and 0.6 epan on red sandy loam soil of bangalore. sharana basava et al. (2012) reported that significant increase in green cob yield at 120 % epan followed by 100% epan levels over 80 and 60%. table 1. effect of drip tape and conventional inline drip irrigation system on yield of sweet corn treatments no. of kernels cob-1 green cob yield (t ha-1) green fodder yield (t ha-1) t1 di at 125 % pe with drip tape system 680.67 19.74 22.58 t2 di at 100 % pe with drip tape system 589.47 17.21 20.97 t3 di at 75 % pe with drip tape system 528.67 15.34 18.97 t4 di at 125 % pe with conventional inline drip system 686.00 19.88 22.93 t5 di at 100 % pe with conventional inline drip system 600.43 17.68 21.52 t6 di at 75% pe with conventional inline drip system 543.33 15.59 19.18 t7 surface irrigation at 0.8 iw/cpe 457.33 13.56 17.30 sed 27.25 0.74 0.87 cd (p = 0.05) 59.37 1.61 1.90 di drip irrigation it is a well known fact that under reduced moisture (stress) condition all the growth factors are affected adversely to a great extent. this was evident from the significant reduction in plant height and number of leaves with surface irrigation as compared to drip irrigation scheduled at 100 % pe. this was the consequence of higher relative plant water content in drip irrigation scheduled at 100 % pe over surface irrigation. the reduction in dry matter production was due to relative moisture stress in the surface irrigation (hariguchi, 1986). the total water requirement under both conventional inline drip and drip tape system was 274.42, 219.54 and 164.65 mm at 125, 100 and 75 % pe respectively which leads to water saving of 36.02, 48.81 and 61.61 % compared to surface irrigation. the water saving under drip irrigation was due to low application rate at frequent intervals matching the actual crop water needs at various stages. under drip irrigation, 75 effect of low cost drip tape irrigation system on yield and economics of sweet corn only a portion of the soil surface around the crop was wetted whereas under surface irrigation the entire field was wetted. under drip irrigation, irrigation was practiced frequently once in two days due to which the soil moisture was always maintained closer to the field capacity. higher plant height of 241.40 cm was found in conventional inline drip system at 125 % pe. this was comparable with drip irrigation at 125 % pe with drip tape system with plant height of 238.10 cm. surface irrigation at 5 cm depth (0.8 iw/cpe ratio) recorded significantly lower plant height of 184.09 cm (table 2). higher frequency of irrigation and increased availability of soil moisture under drip irrigation might have led to effective absorption and utilization of available nutrients and better proliferation of roots resulting in quick canopy growth (ayotamuno, 2007). the highest increase in vegetative growth in this treatment might be due to the availability of soil moisture at optimum level (pattanaik et al., 2003) and application of sufficient nutrients in a readily available form that would have accelerated the production of growth regulators such as auxins (iaa) and cytokinins which in turn stimulated the action of cell elongation and cell division and resulted in increased plant height (anitta fanish and muthukrishnan, 2011). table 2. effect of drip tape and conventional inline drip irrigation system on yield parameters of sweet corn treatments plant height (cm) fresh cob length (cm) fresh cob girth (cm) fresh cob weight (g) t1 di at 125% pe with drip tape system 238.10 21.29 18.37 432.17 t2 di at 100% pe with drip tape system 219.28 19.59 16.87 387.31 t3 di at 75% pe with drip tape system 192.29 17.56 15.41 345.09 t4 di at 125% pe with conventional inline drip system 241.40 22.20 18.81 446.63 t5 di at 100% pe with conventional inline drip system 225.95 20.16 16.89 397.77 t6 di at 75% pe with conventional inline drip system 198.16 17.73 15.50 350.88 t7 surface irrigation at 0.8 iw/cpe 184.09 16.13 14.66 305.17 sed 8.74 0.80 0.69 15.90 cd (p = 0.05) 19.03 1.74 1.49 34.64 di drip irrigation drip irrigation treatments had significant influence on yield parameters. drip irrigation at 125% pe with conventional inline drip system has registered significantly higher fresh cob length, girth and fresh single cob weight of 22.20 cm, 18.81cm and 446.63 g, respectively which were comparable with drip irrigation at 125% pe with drip tape system (fresh cob length-21.29 cm, fresh cob girth-18.37 cm and single fresh cob weight-432.17g). significantly lower fresh cob length, girth and fresh cob weight (16.13, 14.66 and 305.17 g, respectively) were noticed under surface irrigation treatment. ear length decreased with increasing water deficiency. single fresh ear weight values decreased under deficit irrigation (oktem, 2008). eck (1985) stated that water deficiency at grain filling period reduces kernel weight per ear values. the potential yield of maize is determined by kernel weight, it is a certainty that shortage of water stress 76 archana et al. reduces grain yield by reducing kernel weight per ear (kirtok, 1998). karam et al. (2003) reported that grain yield reduced to 37 % under water stress conditions. drip irrigation scheduled at 125 % pe recorded higher net returns in both drip tape system and conventional inline drip system over surface irrigation (fig. 2). this is attributed to higher sweet corn fresh cob yield in this treatment. highest b:c ratio of 3.74 and 3.35 was registered in drip irrigation at 125 % pe in both drip tape and conventional inline drip system respectively. surface irrigation recorded lower b: c ratio of 3.27. drip irrigation at 125 % pe with drip tape system had the highest net returns per total variable cost (2.28) compared to other treatments. this result was similar with findings of maisiri et al. (2005) findings. low cost drip system with granular fertilizer gave the highest gross margin to total variable cost (gm/tvc) ratio of 2.47. this was followed by low cost drip with fertigation with a gm/tvc ratio of 2.37 and the least ratio was found in low cost drip with no fertilizer treatment. fig.2. economics of drip tape and conventional inline drip irrigation systems in sweet corn cultivation. 1 usd = rs. 67.00 conclusion the cost of the drip tape is cheaper when compared to conventional inline drip system. hence this is highly affordable for small and marginal farmers who cannot make higher investment for conventional inline drip system. besides cheaper cost & drip tape system has water saving benefits and distribution uniformity equivalent with that of conventional inline drip system. hence drip tape system is technically feasible and economically viable for substantial yield and income of the small and marginal farmers. references andrade, f. h., c. vega, s. uhart, a. cirilo, m. cantarero and m. valentinuz. 1999. kernel number determination in maize. crop sci. 39: 453-459. b :c r at io r s /h a cost of cultivation ( rs/ha) gross return ( rs/ha) net return ( rs/ha) b: c ratio 77 effect of low cost drip tape irrigation system on yield and economics of sweet corn anitta fanish, s. and p. muthukrishnan. 2011. effect of drip fertigation and intercropping on growth, yield and water use efficiency of maize (zea mays l.). madras agric. j. 98 (7-9): 238-242. ayotamuno, j. m., k. zuofa, o. a. sunday and b. r. kogbara. 2007. response of maize and cucumber intercrop to soil moisture control through irrigation and mulching during the dry season in nigeria. african j. biotechnol 6 (5): 509-515. batra, s. k. 2002. sweet corn: india shift focus to value added maize. press trust of india news letter. bozkurt, s., a. yazar and g. s. mansuroglu. 2011. effects of different drip irrigation levels on yield and some agronomic characteristics of raised bed planted corn. african j. agric. res. 6(23): 5291-5300. brahma bhatt. 2012. response of sweet corn (zea mays l. saccharata sturt) to sulphur and zinc fertilization. res. crops. 13(2): 760. el-hendawy, a. essam abd el-lattief, s. mohamed ahmed and urs schmidhalter. 2008. irrigation rate and plant density effects on yield and water use efficiency of dripirrigated corn. agric. water manage. 95: 836 -844. hariguchi, t. 1986. effect of water deficiency on water potential and protein content of leaves. bulletin of the faculty of agriculture, kagoshma univ. 36: 77-81. karam, f., j. breidy, c. stephan and j. rouphael. 2003. evapotranspiration, yield and water use efficiency of drip irrigated corn in the bekaa valley of lebanon. agric. water manage. 63(2): 125-137. locascio, s. j., s. m. olson and f. m. rhoads. 1989. water quantity and time of n and k application for trickle-irrigated tomatoes. j. amer. soc. hort. sci. 114: 265-268. maisiri, n., a. senzanje, j. rockstrom and s. j. twomlow. 2005. on farm evaluation of the effect of low cost drip irrigation on water and crop productivity compared to conventional surface irrigation system. phys chem earth. 30: 783–791. oktem, a., m. simsek and a. g. oktem. 2003. deficit irrigation effects on sweet corn (zea mays var. saccharata sturt) with drip irrigation system in a semi-arid region. i. water–yield relationship. agric. water manage. 61: 63-74. pattanaik, s. k., n. n. sahu, p. c. pradhan and m. k. mohanty. 2003. response of banana to drip irrigation under different irrigation designs. j. agric. eng. 40(3): 29-34. sharana basava, k. b., suneetha devi, y. sivalakshmi and p. surendra babu. 2012. response of sweet corn hybrid to dripfertigation. j. res. angrau., 40 (4): 101. sivanappan, k. 2004. irrigation and rainwater management for improving water use efficiency and production in cotton crop. in: proceeding of international symposium on “strategies for sustainable cotton production. a global vision” 23 25th november, uas, dharwad, karnataka. tiwari, k. n., r. m. singh and p. k. mal. 2003. effect of drip irrigation on yield of cabbage (brassica oleracea l. var. capitata) under mulch and non-mulch conditions. agric. water manag., 58: 19-28. viswanatha, g. b., b. k. ramachandrappa and h. v. nanjappa. 2000. effect of drip irrigation and method of planting on root and shoot biomass, tasseling silking interval, yield and economics sweet corn (zea mays cv. saccharata). mysore j. agric. sci., 34: 134 141. 78 archana et al. jute (corchorus olitorius l bangladesh agron. j. 2016, 19(2): 29-38 changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizers s. m. mahbub ali1*, m. moynul haque2, m. shahadat hossain3, m. m. hussain4 and m. n. islam5 1planing, training & communication division, bangladesh jute research institute, dhaka 2department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur 3agronomy division, bangladesh jute research institute, dhaka 4grs division, bangladesh jute research institute, dhaka 5pest management division, bangladesh jute research institute, dhaka *corresponding author: mahbubali70@gmail.com keywords: jute seed, nitrogen, phosphorus, chemical changes abstract the study was conducted to determine the effect of nitrogen (n) and phosphorus (p) fertilizer on the physio-chemical changes in composition of jute seed under applied n and p tossa jute (s.n.) cv. o-9897 was grown at five levels of nitrogen (0, 30, 60, 90 and 120 kg n ha-1) and five levels phosphorus (0, 10, 20, 30, 40 kg p ha-1) in late sown condition as seed crop. after harvesting seeds were categorized in to five groups viz. low vigour, medium low vigour, medium vigour, medium high vigour and high vigour which were used for analyzing the chemical composition of jute seed. results revealed that the chemical composition of jute seed was changed under applied nutrient where combination of 120 kg n ha-1and 40 kg p ha-1 gave the highest soluble protein, soluble sugar and ash content while the lowest soluble protein, soluble sugar and ash content and the highest free amino acid and oil content were estimated from the treatment with no nitrogen and no phosphorus fertilizer. introduction jute (corchorus sp.) is the second most important fibre crop after cotton in the world and the main cash crop of bangladesh on an average 9.00-10.00 lakh tons (44-55 lakh bale) of jute fibre was produced annually from an average area of 4.50–5.00 lakh ha of land in bangladesh (bbs, 2012). but the area and production was increased significantly from 2010-2011 and onwards. on an average 75-80 lakh bale jute fibre is produced from 7.00-7.50 lakh ha. of land from 2010-11 and onwards due to developing more conscious about environment and stepping forward to the natural fibre by escaping from the perilous impact of synthetic fibre to the environment. as a result demand of jute fibre is being increased in the recent years both in home and abroad. bangladesh requires about 5000-5500 t of jute seeds every year of which nearly about 12-15% is produced and distributed by the bangladesh agricultural development corporation and the rest of the seeds are solely produced and utilized by the farmers (saha, 2011). traditionally jute seed is produced from fibre crop where seed is sown in the month of march-april and a small portion of crop is kept for seeds at the corner of the field after the harvest of fibre crop. as jute is a short day crop (kundu et al., 1959), it remains in vegetative phase upto october, the seed crop faces many natural hazards in long staying in the field and produces poor quality seeds (hossain et al., 1994). this problem, however, solved by adopting the late sown technology of jute seed production where seed is sown in late condition during the month of august-september aiming entirely for seed purpose. jute seed produced in late sown condition showed unique both in quantity and mailto:mahbubali70@gmail.com 30 mahbub et al. qualitative attributes (hossain et al., 1994). plant nutrients have tremendous influence on yield and quality of jute seed (bhttacharjee et al., 2000). chemical composition of seed is basically determined by genetic factors and variation in species specifically (gadgil et al., 1989). however, chemical composition of seed is influenced to some extent by environmental factors and cultural practices. nitrogen and phosphorus fertilization affect seed yield and physio-chemical characteristics of seed, which may have a major impact on metabolism and subsequent seedling vigour after germination (sam et al., 1982). gradual increase in the level of npk fertilization exerted beneficial effect on growth components, seed yield and seed vigour (bhattacharjee et al., 2000). in jute seeds, the nature of relationship between applied n and protein content, protein content and seed quality yet to be established. chemical composition of jute seed is determined sporadically. gadgil et al., (1989) determined chemical composition of jute seeds of some olitorius and capsularis cultivars and found 11-16% oil content, 16-20% protein and 5-6% ash content. begum (1997) investigated with two cultivars and four other accessions of olitorius jute seed and found 12-13% soluble sugar, 9.50-11.50% lignin, 9-10% hemicelluloses, 14-15% oil content and 9-11% protein. however, the influence of n and p fertilizer on the chemical composition of jute seed and subsequent seed quality has not been investigated elsewhere. therefore, the present study was conducted aiming to determine the chemical composition of jute seed, to assess the changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizer and to find out the relationship between chemical composition and seed quality of jute. materials and methods the experiment was conducted at bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh during september 2007 to january 2008. the climate of the experimental site is sub-tropical in nature having very little rainfall in the mid october and mid november with gradual fall in temperature from last week of october. tossa jute variety o-9897 was used for this experiment. five levels of nitrogen (0, 30, 60, 90 and 120 kg n ha-1) and five levels of phosphorus (0, 10, 20, 30, 40 kg p ha-1) were used as experimental variables. nitrogen was used in the form of urea and phosphorus in the form of triple super phosphate. other fertilizers 20 kg k ha-1 as murate of potash and sulphur 20 kg s ha -1 as gypsum were used as recommended dose. the design was rcbd with three replications. the unit plot size was 3m x 2.5m. all other cultural practices were maintained according to recommendation. after properly collected dried seeds stored in plastic airtight container for determination of its qualitative parameters and chemical composition at three month of seed storage. quality of freshly harvested jute seeds were assessed by germination test, speed of germination, seedling evaluation test, mean days to germination, seedling vigour index, electrical conductivity test, accelerated ageing test as per following procedures. jute seeds were categorized into five groups viz. low vigour, medium low vigour, medium vigour, medium high vigour and high vigour representing n0p0, n30p10, n60p20, n90p30 and n120 p40, respectively applied in the field. seeds harvested from these treatment combinations were used for analyzing the chemical composition of jute seed. the seeds were ground with the help of a mini grinding mill and this grounded seed samples were used to determine the chemical composition of seed. the chemical composition of jute seed viz. total soluble protein, total free amino acid, total soluble sugar, oil content and ash content were measured using the following methodology. total soluble protein estimation 31 changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizers seed extracts were prepared according to kalpana and madhava (1997) and the total soluble proteins were estimated according to lowry et al. (1951). preparation of standard curve protein (bovine serum albumin) the technical grade of bovine serum albumin was used to prepare standard curve of protein. standard protein (bovine serum albumin) solution of different concentration (0, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 mg/20 ml) were prepared. following the above procedure, the optical density of that protein solution of known concentration were measured at 660 µm wave length by a spectrophotometer and standard curve were prepared from protein concentration against the optical density found. the standard curve of total soluble protein is shown in fig. 1. fig. 1. standard curve of total soluble protein determination total free amino acid estimation total free amino acids were estimated according to the method of moor and stein (1948). preparation of standard curve of amino acid (l-serine) the technical grade of l-serine was used to prepare standard curve of amino acid. standard amino acid (l-serine) solution of different concentration (0, 0.50, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0 mg/20 ml) were prepared. fig. 2. standard curve of total free amino acid determination y = 0.0161x + 0.0915 r2 = 0.9812 0.00 0.20 0.40 0.60 0.80 1.00 0 10 20 30 40 50 60 y = 0.0734x + 0.039 r2 = 0.98 0.00 0.10 0.20 0.30 0.40 0.50 0.0 1.0 2.0 3.0 4.0 5.0 6.0 protein concentration (mg/20ml) o p ti ca l de n si ty at 6 6 0 µm amino acid concentration (mg/20ml) o p ti ca l de n si ty at 5 7 0 µm 32 mahbub et al. following the above procedure, the optical density of that amino acid solution of known concentration were measured at 570 µm wave length by a spectrophotometer and standard curve were prepared of amino acid concentration against the optical density found. the standard curve of total free amino acid is shown in fig. 2. total soluble sugar estimation soluble sugar content in the seeds were quantified following anthrone-sulphuric acid method described by shirlaw and glchrist (1967). preparation of standard curve of sugar (glucose) the technical grade glucose was used to prepare standard curve of sugar. standard sugar (glucose) solution of different concentration (0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75 and 3.00 mg/5 ml) were prepared. following the above procedure, the optical density of that soluble sugar solution of known concentration were measured at 630 µm wave length by a spectrophotometer and standard curve were prepared of sugar concentration against the optical density found. the standard curve of total soluble sugar is shown in fig. 3. fig. 3. standard curve of total soluble sugar determination ash content estimation the ash content of jute seed was determined by heating the oven-dry seeds at 5750c in a muffle furnace until the ash weight were constant (five to six hours) according to gadgil et al. (1989). oil content estimation the oil percentage was estimated gadgil et al. (1989) from moisture-free seed meal by solvent extraction using other petroleum ether (boiling point 600c to 800c) in a soxhlet apparatus for eight hours. the meal was pre-dried (600c; 24 hours) two grams of meal was used for the estimation of oil. no further oil was recovered from the residue after eight hours of refluxing. statistical analysis all data were subjected to statistical analysis by analysis of variance (anova) (gomez and gomez, 1984). microsoft excel and mstat software programs were used and y = 0.0662x + 0.0908 r2 = 0.9736 0.00 0.20 0.40 0.60 0.80 1.00 0.0 5.0 10.0 15.0 sugar concentration (mg/20ml) o p ti ca l de n si ty at 6 3 0 µm 33 changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizers the means were compared according to least significant difference (lsd) test. functional relationships among the parameters were established through correlation and regression analysis. results and discussion freshly harvested jute seeds obtained from different doses of nitrogen and phosphorus fertilizers were analyzed to estimate its chemical composition viz. soluble protein, free amino acid, soluble sugar, oil content and ash content. the influence of nitrogen and phosphorus and fertilizers on the chemical composition of jute seed are described below. soluble protein total soluble protein of freshly harvested jute seed influenced significantly by applied nitrogen and phosphorus fertilizers (table 1). total soluble protein increased with the increase of the levels of n and p fertilization. total soluble protein ranged from 196.30 mg g-1 (19.63%) to 224.90 mg g-1 (22.49%) which is an agreement with the findings of gadgil et al. (1989) who found 16-20% protein in jute seeds. the highest total soluble protein (224.90 mg g-1) was estimated from the seeds harvested from 120 kg n ha-1 and 40 kg p ha-1 followed by the treatments 90 kg n ha-1 and 30 kg p ha-1. the lowest total soluble protein (196.30 mg g-1) was found from the seeds with no n and p fertilizers. chakravorty and singh (1979) also observed that seed protein content increased in cotton seed with increasing n rates. this was because of increased n rates increased n content and subsequently protein content in seeds. as nitrogen is essential component of proteins and related to amino acids, it governs considerable degree in the utilization of nutrients including p (brady, 1984). abdel bagi et al. (2002) conducted an experiment with roselle (hibiscus sabdariffa var. sabdariffa l.) and reported that nitrogen and phosphorus fertilizers increase the seed protein content which has important implications on seed quality. in present study, there is also positive correlation between the total soluble protein content and germination percentage of jute seed (fig. 4). table 1. effect of nitrogen and phosphorus fertilizer on total soluble protein of tossa jute seed treatment combination total soluble protein (mg g -1) percentage n0 p0 196.30 d 19.63 n30 p10 201.30 cd 20.13 n60 p20 201.90 c 20.19 n90 p30 206.30 b 20.63 n120 p40 224.90 a 22.49 lsd (0.05) 1.02 cv (%) 1.30 means followed by common letter are not significantly different at 0.05 levels by lsd. 34 mahbub et al. fig. 4. relationship between total soluble protein and germination percentage obtained from different level of nitrogen and phosphorus fertilizers free amino acid total free amino acid of tossa jute seed significantly influenced by the different levels of nitrogen and phosphorus fertilizers (table 2). in general higher amount of free amino acid was found from the seeds obtained from the treatment with lower level of n and p fertilization and it decreased with the increasing level of n and p fertilizers. the highest total free amino acid (20.99 mg g-1) was estimated from the seeds with no n and p fertilizers and the lowest amino acid content (15.62 mg g -1) was found from the seeds of the treatments with 120 kg n and 40 kg p ha-1. if table 1 and table 2 are compared, then it may be seen that free amino acid content was decreased with the increase of total soluble protein. fig. 5 illustrated the similar scenario that amino acid decreased with the increase of protein in jute seed. tsai et al. (1992) reported that protein content increased from applied nitrogen which was accompanied by an increase in the amount of zein present in the endosperm. increase in zein content in endosperm reduces the lysine and tryptophan concentrations, thus reducing the total free amino acid. verma et al. (1999) reported that plants take up nitrogen preferably as ammonia and then convert it into glutamine and glutamic acid. these two amino acids act as nitrogen donors for the proline and arginine biosynthesis which reduced the free amino acid and maintained essential amino acid contents in the seed. table 2. effect of nitrogen and phosphorus fertilizer on total free amino acid content of tossa jute seed treatment combination total free amino acid (mg g -1) percentage n0 p0 20.99 a 2.10 n30 p10 18.81 b 1.88 n60 p20 19.08 bc 1.91 n90 p30 17.17 d 1.72 n120 p40 15.62 e 1.56 lsd (0.05) 0.776 cv (%) 2.57 means followed by common letter are not significantly different at 0.05 level by lsd. y = 0.0239x + 93.691 r = 0.729 97.50 98.00 98.50 99.00 99.50 100.00 190 195 200 205 210 215 220 225 230 total soluble protein (mg g-1) g er m in at io n (% ) 35 changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizers fig. 5. relationship between total soluble protein and total free amino acid obtained from different level of nitrogen and phosphorus fertilizers. soluble sugar total soluble sugar of tossa jute seed influenced profoundly by the application of nitrogen and phosphorus fertilizers (table 3). total soluble sugar increased with the increase of the levels of n and p fertilization and it increased from 11.34 to 12.70%. this agrees well to begum (1997) who found 12-13% soluble sugar from tossa jute seed. the highest total soluble sugar (121.70 mg g-1) was estimated from seeds of the treatments with 120 kg n ha-1 and 40 kg p ha-1 and it was lowest (113.40 mg g-1) in the treatment without nutrient. in this regard achakzai and kayani (2002) reported that total soluble sugar significantly increased with added nitrogen fertilizer in soybean seed. presence of soluble sugar in seed has great implication on seed quality as there is positive correlation between the total soluble sugar content and germination percentage of jute seed (fig. 6) which indicated that higher the amount of soluble sugar higher the germination percentage. table 3. nitrogen and phosphorus fertilizer effects on the total soluble sugar content of tossa jute seed. treatment combination total soluble sugar (mg g -1) percentage n0 p0 113.40 e 11.34 n30 p10 115.60 d 11.56 n60 p20 117.90 c 11.79 n90 p30 119.00 b 11.90 n120 p40 121.70 a 12.70 lsd (0.05) 0.26 cv (%) 1.14 means followed by common letter are not significantly different at 0.05 levels by lsd. y = -0.1482x + 49.101 r = 0.979 15 17 19 21 23 25 190 195 200 205 210 215 220 225 230 t o ta l fr ee am in o ac id (m g g1 ) total soluble protein (mg g-1) 36 mahbub et al. fig. 6. relationship between total soluble sugar and germination percentage obtained from different level of nitrogen and phosphorus fertilizers. oil content oil content of tossa jute seed was also significantly influenced by the different levels of n and p fertilization which ranged from 13.74% to 15.60%. gadgil et al. (1989) found 11-16% and begum (1997) found 14-15% oil content in tossa jute seed which is almost an agreement with the findings of present study. increased level of n and p fertilization decreased seed oil content but it was inconsistent (table 4). the highest oil content (15.60%) was found from the seeds with no n and p fertilizers and the lowest oil content (13.74%) was found from seeds of the treatment with 120 kg n and 40 kg p ha-1. several investigators observed that nitrogen and phosphorus fertilization affect seed oil content differently in different field crops (ref.). cotton seed oil content decreased with the increase of n fertilization (sam et al., 1982) and p fertilization (chakravorty and sing, 1979). ash content ash content of jute seed varied from 6.12 to 7.24% due to applied n and p fertilization (table 4). the highest ash content (7.24%) was found from the seeds harvested from the treatment with 120 kg n ha-1 and 40 kg p ha-1 and it was lowest (6.12%) in seeds with no fertilization. other treatments contributed intermediate amount of ash content in jute seeds. table 4. effect of nitrogen and phosphorus fertilizer on the oil and ash content of tossa jute seed treatment combination oil ( % ) ash ( % ) n0 p0 15.60 a 6.12 c n30 p10 14.50 c 6.73 b n60 p20 14.95 b 6.75 b n90 p30 14.35 d 6.76 b n120 p40 13.74 e 7.24 a lsd (0.05) 0.07 0.05 cv (%) 1.34 1.38 y = 0.1248x + 84.023 r = 0.860 97.00 97.50 98.00 98.50 99.00 99.50 100.00 113 114 115 116 117 118 119 120 total soluble sugar (mg g-1) g er m in at io n (% ) 37 changes in chemical composition of jute seed as influenced by nitrogen and phosphorus fertilizers means followed by common letter are not significantly different at 0.05 levels by lsd. the amount of ash in jute seed found in present study however differed to that of gadgil et al. (1989) who reported only 5% ash in jute seeds. higher amount of ash content in seeds of present study might be associated with the increase in thousand seed weight due to applied nutrients as there is positive relationship between thousand seed weight and ash content in jute seed (fig. 7). fig. 7. relationship between seed weight and ash content obtained from different level of nitrogen and phosphorus fertilizers. conclusion from the study it could be concluded that the chemical composition of jute seed was changed due to applied nutrients, where seeds produced with120 kg n ha-1 and 40 kg p ha-1 gave the highest soluble protein, soluble sugar and ash content while lowest in free amino acid and oil content. on the other hand, these results affected inversely on seed germination and seed vigour when the treatments had no nitrogen and phosphorus fertilizer. references abdel bagi, a. a., t. e. m. hago and f. e. g. ahmed. 2002. chemical composition of roselle (hibiscus sabdariffa var. sabdariffa l.) as affected by genotype and itrogen, phosphorus and sulphur fertilization. u. of k. j. agric. sci. 10: 1-15. achakzai, a. k. k. and s. a. kayani. 2002. effect of fertilizer, inoculation and sowing time on chemical composition of field grown soybean seeds. asian j. plant sci. 1: 618-621. bbs (bangladesh bureu of statistics). 2012. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning, government of the peoples republic of bangladesh. begum, s. 1997. physiological and biochemical studies on the low temperature tolerance in tossa jute (corchorus olitorius l.). unpublish ph.d. thesis, department of botany, university of dhaka. bangladesh. y = 2.9505x + 0.0125 r = 0.894 6.00 6.20 6.40 6.60 6.80 7.00 7.20 7.40 2.10 2.15 2.20 2.25 2.30 2.35 2.40 2.45 2.50 a sh co n te n t (% ) thousand seed weight (g) 38 mahbub et al. bhattacharjee, a. k., b. n. mittra and p. c. mittra. 2000. seed agronomy of jute. ii. production and quality of corchorus olitorius seed as influenced by nutrient management. seed sci. technol. 28:141-154. brady, n. c. 1984. the nature and properties of soils (9th ed.) mcmillan publishing co. inc. usa. chakravorty, s. c. and s. singh. 1979. effect of fertilizes (npk) on seed weight, protein content and oil composition of cotton (g. hirsutum). indian agric. 23: 165-171. gadgil, j. d., k. n. susseelan, r. mitra, d. c. joshua and c. r. bhatia. 1989. chemical composition of seed and electrophoretic pattern of seed storage protein of jute corchorus olitorius and corchorus capsularius. seed sci. technol. 17:499506. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. second edn. john wiley and sons. inc. new york. pp.304-307. hossain, m. a., s. a. mannan, m. k. sultana and a. l. khandakar. 1994. survey on the constraints of quality jute seed at farm level. ministry of agriculture, agricultural support service project. gob/world bank/oda seed technological research team, bangladesh jute res. inst. dhaka. p. 25. kalpana, r and k. v. madhava rao. 1997. protein metabolism of seeds of pigeon pea cultivars during accelerated ageing. seed sci. technol. 25: 271-179. kundu, b. c., k. c. basak and p. b. sarker. 1959. jute in india. the indian central jute committee. pp. 74-136. lowry, o. h., n. r. j. rosebrough, a. l. farr and r. j. randail. 1951. protein measurement with the folin phenol reagent. j. biol. chem. 193: 265-275. moor, s. and w. h. stein. 1948. photometric ninhydrin method for use in the chromatography of amino acid. j. biol. chem. 176: 367-387. saha, c. k. 2011. jute seed management in bangladesh. international seminar on strengthening of collaboration for jute, kenaf and allied fibres research and development (held during june 8-9, 2011). international jute study group (ijsg). pp. 92-97. sam. m. j., s. n. bhola, y. s. yadav and a. prasad. 1982. response of cotton hybrids to nitrogen and phosphorus. indian j. agron. 27: 13-17. shirlaw, d. w. and d. w. grlchrist. 1967. a practical course in agricultural chemistry. pergamon pub. london, u. k. pp. 122-130. tsai, c. y, i. dweikat, d. m. huber and h. l. warren. 1992. interrelationship of nitrogen nutrition with maize (zea mays) grain yield, nitrogen use efficiency and grain quality. j. sci. food agric. 58: 1–8. verma, d. p. s. and c. s. zhang. 1999. regulation of proline and arginine biosynthesis in plants. in plant amino acids: biochemistry and biotechnology. new york. pp. 249-265. bbs (bangladesh bureu of statistics). 2012. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning, government of the peoples republic of bangladesh. long-term bed planting trial for enhancing sustainable crop production in drought prone areas bangladesh agron. j. 2014, 17(1): 23-32 long-term bed planting effect on stabilizing productivity of rice and wheat in a drought prone area of bangladesh m. ilias hossain1, m. i. hossain2, m. r. i mondal3, m. k. sultan4, m. gathala5 and t. p tiwary5 1 senior scientific officer (agronomy), 2principal scientific officer (agril. engg.), 3director general and 4 director (research) of bangladesh agricultural research institute, gazipur and 5cropping system agronomists, cimmyt bangladesh corresponding author: iliasrwrc@gmail.com key words: bed planting, cropping system, productivity, sustainable, drought abstract the systems productivity, soil fertility and n use efficiency were evaluated in a drought area of rajshahi under five n fertilizer levels (0, 40, 80, 100 and 120 % n of the recommended dose, two straw retention (sr) (0 and 30%) and two tillage options [raised bed and conventional tillage (ct)] in a long term bed planting experiment with rice-wheat (rw) systems. the findings revealed that the permanent raised beds (prb) with 30% straw retention had the highest productivity for all the three crops in the sequence. within each n rate the total system (ricewheat-mungbean) productivity was higher with 30% sr on prb and the least in ct with 0 % sr. at 80 % of recommended fertilizer n rate, mean annual system productivity was 12.8 t ha-1 for prb with 30% sr, 11.2 t ha-1 with prb on 0% sr and 10.3 t ha-1 with ct without straw. n uptake and use efficiency increased with increasing n levels with bed planting up to 120% n application (120 kg n ha-1) in wheat, both 100% (80 kg n ha-1) in rice and (20 kgn ha-1 ) in mungbean for all the years. system productivity in n unfertilized plots increased when straw was retained. the results suggest that n fertilizer rates can be reduced when straw is retained. soil organic matter in surface soil layers of the prb had increased by 0.72% after eight years (8 ricewheat-mungbean crop cycles) with 30% sr. it may be inferred that straw retention is an important component of soil management and may have long term positive impacts on soil quality compared with conventional tillage with 0 % sr. the combination of prb with nutrients and residues retained appeared to be a very promising technology for sustainable intensification of rw systems in the drought prone area of bangladesh. introduction land degradation and soil fertility declining are among the main causes of the stagnation and fall of agricultural productivity in many tropical countries including those with intensive irrigated cropping systems. approximately 85% of the area planted with intensive rice-wheat (rw) sequential cropping is found in the indo-gangetic plain (igp) of south asia in india, pakistan, nepal and bangladesh (timsina and connor, 2001). rice is transplanted in flat fields are typically ponded for long periods or continuously from transplanting until shortly before harvest. this negatively affects soil properties for the following non-puddle crop (hobbs ad giri, 1998). wheat is then planted in these structurally disturbed soils, often after many tillage operations to get the prepared the seedbed or increasingly, with little soil disturbance using zero-till seed drills. a change from growing crops on the flat to raised beds offers more effective control of irrigation water and drainage. this may be particularly beneficial for non-rice crops grown in rotation with rice, allowing better rainwater management during the monsoon season for rice. connor et al. (2003) suggested that permanent raised beds might offer the farmers further significant advantages related to increased opportunities for crop diversification, mechanical weeding and placement of fertilizers, relay cropping and inter-cropping, and reduced tillage and water saving. there are also indications that crop yields from beds can be further increased by using higher rates of n fertilizer and later irrigation because of the reduced risk of lodging (sayre and ramos, 1997). raised beds are increasingly used in many developed and developing countries in mechanized agriculture but have been 24 hossain et al. introduced only recently in bangladesh, with the aim of improving system productivity (talukder et al., 2002). inclusion of grain legumes in the dry-wet transition of rice-wheat cropping system as a third crop may be the other option of increasing cropping intensity, soil fertility and productivity of the system. although the non rice season across the rice-wheat area is characterized with low rainfall, heavy pre-monsoonal rain can have disastrous effects on the third crop, such as maize or mungbean grown after wheat or before rice, both during establishment and grain filling causing water logging (timsina and connor, 2001; quayyum et al., 2002). due to lack of crop establishment technique and temporary water logging at reproductive stage, inclusion of a grain legume like mungbean in rice-wheat cropping system very often faces problem. bed planting may be a solution of this problem because raised beds not only facilitates irrigation but also drainage and therein lays their potential to increase the productivity of crops other than rice in the system. growing leguminous crops in a cropping system is beneficial not only for economic products but also for soil amelioration (singh et al., 1993). the common practice of rice in puddle soils destroys the soil physical structure that has implications for the following wheat crop (hobbs et al., 2000). crop residues are an important source of soil organic matter vital for the sustainability of agricultural ecosystems. about 25% of n and p, 50% of s and 75% of k uptake by cereal crops is retained in crop residues, making them valuable nutrient sources (singh, 2003). however, straw retention is not a common practice in the rw systems of bangladesh. wheat and rice straw are usually removed from fields for use as cattle feed and thatching material for houses or for fuel, leaving little for incorporation into the soil. as a result, soil organic matter levels have declined in these cropping systems, and optimization of nutrient uptake and absorption efficiency. in a study talukder et al. (2002) found that n use efficiency was the highest in permanent raised beds, giving higher yields than a conventional system. limon-ortega et al. (2000) observed that permanent beds with straw retention had the highest mean wheat grain yields (5.57 t ha-1), n use efficiency (28.2 kg grain kg-1 of n supply) and total n uptake (133 kg ha-1), with positive implications for soil health. thus, management of crop residues and beds, along with efficient n fertilization strategies are new farming practices that can increase and maintain yields from the intensive rw system in bangladesh. therefore, this study was undertaken in a drought prone area in north-western part at rajshahi to evaluate the system productivity, soil fertility and n use efficiency of intensive wheat-mungbean-rice crops sequence tested on permanent raised bed (prb) compared to conventionally tilled systems. materials and methods wheat (triticum aestivum)mungbean (vigna radiata)monsoon rice (oryza sativa) cropping pattern was followed for 8 times, at the regional wheat research centre, shyampur, rajshahi, bangladesh (24o3'n, 88041e, 18 m above sea level). the site has a subtropical climate and is located in agro ecological zone 1 (old himalayan piedmont plains) on flood-free high land, with course-textured, highly permeable soil (barc, 1997). the area receives 1,757 mm mean annual rainfall, about 97% of which occurs from may to september. total rainfall was the highest during the mungbean season and the lowest in the wheat season in all years (table 1). the trial involved a three-crop sequence i.e., rice-wheat-mungbean (rwm) planted on raised beds and conventional. rice was transplanted (one 25-day-old seedlings per hill) with spacing 30 cm x 15 cm in late july and harvested in late november by hand. wheat was seeded with 100 and 120 kg seed ha-1 for beds and conventional, respectively, in late november and harvested in late march. after harvest of wheat, mungbean were planted in march with seeding rate of 35 kg ha-1 in early april and harvested in mid july for both beds and conventional. the trial was originally established as a prb experiment with two straw management practices (main plots-30% straw retention (sr) and 0% sr) and five n levels (subplots 0, 40, 80, 100 and 120% of recommended). the area of each subplot was 15 m2 (5m x 3m). the 25 bed planting effect of rice and wheat in drought prone area experiment consisted of 20 subplots with four tillage/straw treatments (30% sr + prb, 30% sr + ctp, 0% sr + prb and 0% sr + ctp) and five n levels (0, 40, 80, 100 and 120% of recommended) with three replication. after planting the wheat or rice, straw from the preceding cereal crops was returned as a mulch into the plot from which it had been removed at harvest. after harvesting and threshing, the rice and wheat straw were returned without chopping as standing way. the width of the beds was 60 cm (furrow to furrow) and the depth of the furrows on average was 15 cm. two rows of wheat (var. shatabdi) or rice (var. brri dhan 49) with a spacing of 30 cm, were planted by hand sowing on the beds, two rows of rice on the beds, mungbean (var. bari mungbean-6) was sown by bed former in the furrows between the beds. the mungbean was harvested about 60 days after sowing (das). in ctp, wheat, rice and mungbean were planted in 20 cm, 30 x 15 cm and 30 cm in continuous rows. a basal dose of p (20, 22 and 26 kg ha-1) from triple super phosphate, k (15, 35 and 33 kg ha-1) from muriate of potash and s (10, 11 and 20 kg ha-1) from gypsum was applied to mungbean, rice and wheat, respectively. in rice the entire amount of pks was broadcasted before transplanting and mulching on both prb and ctp. for ctp the fertilizer was broadcast before tillage as is the usual practice. the recommended rate of n (80 kg ha-1for rice, 100 kg ha-1 for wheat and 20 kg ha-1 for mungbean) was applied as urea. for mungbean all n was applied before seeding. with ctp, n was broadcast, while with beds it was banded on top of the soil between two rows in three equal installments 15, 30 and 45 days after transplanting, while wheat, two-thirds of the n was applied before seeding and the remaining onethird at crown root initiation (cri). sufficient irrigation water was applied to fill the furrows between the raised beds. total system productivity total system productivity (tsp) was calculated using the method of tanaka (1983). based on the composition of harvested organs for mungbean and their conversion efficiencies, the equivalent yields for various crops can be calculated (tanaka, 1983). total system productivity (tsp) for each treatment was calculated as the total annual productivity (or the annual total of economic yield of the individual crops) based on equivalent yields. estimation of nitrogen uptake the result was expressed in percentage. n-uptake by grain and straw also were calculated by the following formulae: n-uptake by grain (kg ha-1) = total n (%) in grain x grain yield (kg ha-1) 100 n-uptake by straw (kg ha-1) = total n (%) in straw x straw yield (kg ha-1) 100 different measures of nitrogen use efficiency the different measures of n-use efficiencies; physiological efficiency (pe), fertilizer recovery efficiency (re), and agronomic efficiency (ae) were calculated as described by dobermann and fairhurst (2000). total n uptake as used in this term referred to n uptake by above ground biomass (grain and straw) only recovery efficiency (re) of added n was calculated as: re (%) = total n uptake (kg n ha-1) of the treatment total n uptake (kg n ha-1) of the control x 100 [1] applied n (kg n ha-1) of the treatment physiological efficiency (pe) of added n was calculated as: pe(kg grain kg -1 n uptake) = grain yield (kg ha-1) of the treatment – grain yield (kg ha-1) of the control [2] total n uptake (kg n ha-1) of the treatment – total n uptake (kg n ha-1) of the control 26 hossain et al. agronomic efficiency (ae) of added n was calculated as: ae(kg grain kg -1 n applied)= grain yield (kg ha -1) of the treatment – grain yield (kg ha -1) of the control [3] applied n (kg n ha -1) of the treatment statistical analysis of data the data were analyzed statistically following computer package mstat and the significance of mean differences was adjusted by duncan’s multiple range test. results and discussion total system productivity (tsp) tsp increased by 12-15% with 30% straw retention with prb (12 t ha-1yr-1) compared with ctp with 0% straw retention (fig. 1). for all crops the highest system yields obtained in prb + 30% sr. yields on prb consistently increased significantly as sr increased from 0% to 30. the lower system productivity with 0% sr with ctp was associated with reduced crop growth. similar observations were made by singh et al. (2003) in mexico. fig. 2 presents the system yields of different tillage options and n levels (means of three years), illustrating that tsp increased significantly by 11 % in rice and 14 % in mungbean with increasing n levels up to 100 %; and by 16 % in wheat up to 120 % n. for all crops the highest system productivity occurred in prb with 120 % n (120 kg n ha-1 in wheat) and 80 % n both in rice and mungbean (80 kg n ha-1 in rice, 20 kg n ha-1 in mungbean). yields tended to be lower with lower nitrogen levels for all crops. similar observations were made by yadvinder et al. (2006) in india. averaged over the years, prb + 30 % sr with 100 % n gave a 17 % increase in wheat yield over prb + 0 % sr at the same n rate, but there was no significant mungbean yield increase with additional n with 30% sr. however, yield of prb + 30% sr with 120% n was significantly higher than prb + 0 % sr with 100% n in wheat. average rice yield on prb + 30% sr with 50% n was significantly higher than with 0 % sr at the same n rate, and there was no further yield increase at higher n rates. rice yield declined with 30 % sr at the two highest n rates, mostly due to lodging. 0 2 4 6 8 10 12 14 bed x 0% straw conv x 0% straw bed x 30% straw conv x30% straw tillage options x straw levels to ta l s ys te m s pr od uc tiv ity (t /h a) rice wheat mungbean 0 2 4 6 8 10 12 14 bed x0% n conv x0% n bed x40 %n conv x40 %n bed x80 %n conv x80 %n bed x10 0%n conv x10 0% n bed x12 0%n bed x12 0%n tillage optionsx n levels to ta l s ys te m p ro du ct iv ity (t/ ha ) rice wheat mungbean fig 1. total system productivity under tillage options and straw levels in rice-wheatmungbean system fig. 2. total system productivity under tillage options nitrogen levels in rice-wheatmungbean systems lower system productivity also occurred from 0% n with ct due to less n uptake and use efficiency. yields tended to be lower in differences of nitrogen levels for all crops. similar observations were made 27 bed planting effect of rice and wheat in drought prone area by yadvinder et al. (2006) in india. yields tended to be lower in differences at four n levels in wheat, at three n levels in rice and at two lowest n levels in mungbean (fig. 2). averaged over the 7 years, prb + 30% sr with 100 % n gave 17 % increased in wheat yield over prb + 0 % sr at the same n rate (fig. 2). however, yield of prb + 30% sr with 120% n was significantly higher than prb + 0% sr with 100% n. average rice yield on prb + 30% sr with 50% n was significantly higher than with 0% sr at the same n rate, and there was no further yield increase at higher n rates, rice yield declined with 30% sr at the two highest n rates, mostly due to lodging. maximum average wheat grain yield was obtained on prb from 120 % n with 30 % sr and after 7 years yield was similar when 80 % n with 30% straw retention (fig. 2). these yield increases with straw retention are probably due to suppression of soil evaporation, less weeds and more efficient use of fertilizers. limon-ortega et al. (2000) reported that permanent beds both wheat and maize yields when grown with higher rates of n fertilizer. rice yield was comparatively low under the ctp system due to water logging and the resultant acute weed stress (poor crop growth could not compete as well with weeds) in early as well as late growth stages. variability in wheat yields in bangladesh is mostly the result of the high temperature that can occur during the grain filling phase, especially for late-sown crops (midmore et al., 1984). nitrogen uptake and use efficiency 0 20 40 60 80 100 120 140 160 0 40 80 100 120 applied n levels (% recommondation) n up tak e ( kg /ha ) bed + 0%sr conv + 0%sr bed + 30%sr conv + 30%sr fig. 3. total nitrogen uptake under tillage options, straw and nitrogen levels in ricewheat-mungbean systems total n uptake increased with increasing up to 120 % and it was similar as 80 % in all crops. the increased n uptake was 31% in rice, 25 % in wheat and 19 % in mungbean over conventional (fig. 3). retention of straw resulted in increased n uptake in both n fertilized and zero n plots. nitrogen uptake was significantly (p<0.5) influenced by straw retention and n level. in prb + 30% sr plots, total n uptake by rice was maximum at 50-100 % by rice, 80-120 % by wheat and 50-100 % by mungbean. in contrast, in both prb and ctp without straw retention, there was a consistent trend for increasing n uptake up to 120 % n rate in all crops. limon-ortega et al. (2000) also observed that permanent beds with straw retention gave the highest wheat grain yields (5057 t ha-1), n use efficiency (28.2 kg grain kg-1 of n supply) and total n uptake (133 kg ha-1). yield in n unfertilized rice, wheat and mungbean increased when straw was retained and this appeared to be due to an increased uptake of n. fertilizer use efficiency may be increased by implementing permanent bed management in addition to reducing weed and crop lodging problems. n use efficiency (calculated pe, ae and re) decreased as n rate increased in all treatments (table 1). at the lowest n rate there was a consistent trend for higher ae on prb with 30 % sr and 0 % sr. there was a consistent trend for higher pe on prb as the amount of sr increased from 0 to 100% across all crops. similar observations were made by yadvinder et al. (2004). they reported that ae was significantly higher in straw retained + green manure cultivated treatments than other treatments for wheat. n uptake helps the decomposition of retained straw, resulting in a higher uptake of nutrients and more efficient use of water. n use efficiencies increases rice life 3-5 days. table 1. nitrogen use efficiency of rice, wheat and mungbean (2004-12) as influenced by straw retention, 28 hossain et al. tillage and n level at rajshahi, bangladesh. treatments ae (kg grain kg-1n applied) pe (kg grain kg-1n uptake) re (%) rice wheat mungbean rice wheat mungbean rice wheat mungbean 30 % sr + prb n0 64.5 44.5 49.5 n50 49.3 33.5 16.5 53.4 33.5 36.8 95.4 96.8 112.7 n100 41.2 24.3 10.6 45.8 26.2 32.3 89.8 81.7 106.3 n150 23.5 18.5 6.7 41.4 25.7 25.3 66.2 64.7 95.7 n200 20.2 14.5 3.9 38.2 23.4 22.4 50.9 45.2 77.6 0 % sr + prb n0 58.3 39.5 43.5 n50 42.3 28.3 12.8 49.8 29.5 31.5 87.8 84.5 95.3 n100 34.5 21.5 9.7 41.5 22.4 27.3 78.6 74.6 87.3 n150 21.3 14.3 6.3 38.9 18.5 22.5 58.6 62.5 82.1 n200 18.5 10.5 3.2 29.6 11.5 18.3 42.5 53.2 63.2 30 % sr + ctp n0 59.6 44.5 44.5 n50 45.3 29.5 14.5 50.2 34.2 32.4 90.2 87.3 98.6 n100 38.5 22.3 10.2 43.2 25.3 28.3 82.3 77.3 89.3 n150 25.4 19.3 6.4 37.8 22.3 23.2 60.5 65.3 82.5 n200 20.3 12.4 3.4 30.5 13.5 19.7 44.5 53.4 68.5 0 % sr + ctp n0 52.3 45.3 57.6 n50 38.7 24.1 12.6 49.6 33.7 43.5 82.7 81.3 97.2 n100 33.4 20.4 9.6 42.2 27.9 34.5 71.4 71.2 81.4 n150 19.2 16.2 6.4 37.5 26.8 30.9 48.9 59.6 71.6 n200 14.7 9.9 2.6 33.2 24.8 24.3 39.2 44.3 58.5 prb = permanent raised beds, sr = straw retention; ctp = conventional tillage practice soil organic matter (som) after 8 years (2004-12), retention of straw from all three crops in the zero-till prb system had increased the soil organic matter by 0.72% (table 2). while some of the increase may have been due to formation of the beds from topsoil, the change in organic c increased as the rate of residue retention increased from 100%, indicating that straw retention also affected organic c on the beds. 30% sr with prb, p, k and zn availability increased. at low n levels (0 and 50% of recommended) there appeared to be a slight decline in soil organic c. after 8 years of ctp without residues, soil organic c had decreased by a few percent at all n rates and there was a consistent trend for a large decline at lower n rate. the increase in soil organic c with 30% sr at 50-150% n was almost double that with 0 % n. kumar and goh (2000) reported that, in the longer term, residues and untilled roots from crops can contribute to the formation of som. after the seven rwm crop cycles, the soil color had darkened, presumably due to the build-up of organic matter in the topsoil (fig. 4). table 2. chemical properties changes in soil for 30% straw from 2004-2012 bed x 0 % straw bed x 0 % straw conv. x 0% straw bed x 30% straw conv. x 30% straw ph 8.2 8.3 7.7 7.9 om (%) 1.06 1.06 1.78 1.24 total n (%) 0.11 0.12 0.09 0.11 p (mg g-1 soil) 15.12 14.5 19.87 16.75 k ml (eq 100 g-1 soil) 0.37 0.39 0.48 0.43 29 bed planting effect of rice and wheat in drought prone area s (mg g-1 soil) 17.25 24.2 15.85 21.27 zn (mg g-1 soil) 0.23 0.12 0.37 0.17 b (mg g-1 soil) 0.31 0.21 0.35 0.24 ec (ds m-1) 0.97 1.24 0.92 1.17 table 3. soil chemical properties changes for 30 % straw retention after eight years characteristics initial final difference ph (1:2.5 in water) 8.3 8.0 0.3 organic matter (%) 1.10 1.82 + 0.72 total n (%) 0.12 0.09 0.03 exch. k (ml eq 100g-1 soil) 0.26 0.48 + 0.22 avail. p (mg g-1 soil) 24.5 52.5 + 38.0 avail. s (mg g-1 soil) 25.6 38.9 + 13.3 avail. zn (mg g-1 soil) 0.84 6.13 + 5.29 avail. b (mg g-1 soil) 0.19 0.37 + 0.18 ca (ml eq 100g-1 soil) 18.22 21.24 + 3.02 mg (ml eq 100g-1 soil) 5.05 6.17 + 1.12 fe (mg g-1 soil) 76.4 63.5 12.9 mn (mg g-1 soil) 22.9 12.7 10.2 economic evaluation of conservation agriculture (ca) for economic evaluation, considered 20 farmers for permanent bed and 25 farmers for new bed in both the cases. from table 4, observed that total 25% cost saved of t. aman rice production in prb and 17% cost saved in new bed over farmers practice as well as more than double net return from both permanent and new bed system over farmers practice (fp). it also observed that economically higher return from both prb (28%) and new beds (34%) than fp. however, ca is more economically viable than fp. table 4. economic performance of ca for t aman rice in 2010-12 from farmers factors permanent (n=20) new (n=25) bed fp change bed fp change tillage / land preparation 250 480 -47% 480 480 seed 140 200 -30% 140 200 -30% fertilizer & pest management 650 780 -16% 650 780 -16% irrigation 450 760 -40% 480 760 -36% weeding 395 550 26% 420 550 -23% harvest 510 560 -9% 520 560 -7% threshing 230 200 230 200 total costs 2625 3530 -25% 2920 3530 -17% yield (kg bigha-1) 760 590 28% 795 590 34% value @ tk 10 kg-1 7600 5900 28% 7950 5900 34% net return 4975 2370 2605 (2.1x) 5030 2370 2660 (2.12x) conclusion retention of 30% crop residues together with zero-till permanent bed system offers an important soil restorative management strategy likely to have a long-term positive impact on soil quality and crop productivity in intensive rice-wheat-mungbean (rwm) cropping systems in bangladesh. besides, residual straw and roots added more organic matter and nutrients into the soils under prb, resulting in increased nutrient uptake by the crops. crop productivity on beds with 30 % straw retention increased by 30 hossain et al. 11% for rice, 17% for wheat and 21% for mungbean at 100% n rates over a 7 year cycle of the rwm cropping pattern compared with 0 % sr+ prb at the same n rate. yield in n unfertilized rice, wheat and mungbean increased when straw was retained and this appeared to be due to an increased uptake of n. retention of crop residues as a mulch reduced moisture depletion and increased som content over relatively short periods of time. fertilizer use efficiency may be increased by implementing permanent bed management in addition to reducing weed and crop lodging problems. permanent raised beds would also help ameliorate the adverse effects of tillage on soil structure, which might lead to water logging under excess water conditions and hamper establishment, growth and development of most crops including mungbean. the use of prb reduces the overall cost of production and long turnaround time. thus, results showed that prb with straw retention could help to intensify rw systems to rwm systems under high degrees of management as such further on-farm adaptive trial with farmers is needed to verify the technology. acknowledgement we acknowledge the international wheat and maize improvement centre (cimmyt) for financial support for conducting this study. references gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research (second edition).john wiley & sons, inc., irri, philippines, 680p. govaerts b, k. d. sayre and j. deckers. 2006. towards minimum data sets for soil quality assessment. the case of zero-tillage wheat/maize rotations in the highland of mexico. soil till. res. 87: 163-174. gupta, r. k., r. k. naresh, p. r. hobbs and j. k. ladha. 2002. adopting conservation agriculture in ricewheat systems of the indo-gangetic plainsnew opportunities for saving on water. paper presented at the "water wise rice production workshop", 5-10 april 2002, irri, philippines. hobbs, p. r and r. k gupta. 2000. ‘soil and crop management practices for enhanced productivity of the ricewheat cropping system in the sichuan province of china’. rice-wheat consortium paper series 9. (rwc, new delhi, india). ippc. 2007. fourth assessment report of the intergovernmental panel on climate change: the impacts, adaptation and vulnerability. cambridge university press, united kingdom and new york, ny, usa. kataki, p. k. 2001. the rice-wheat cropping system in south: trends, constraints and productivitya prologue, j. crop prod. 3: 1-26. kumar, k. and k. m. goh. 2000. crop residue management, effects on soil quality, soil nitrogen dynamics, crop yield and nitrogen recovery. adv. agron. 68: 197-319. lauren, j. g., j. m. duxbury, m. i. hossain, g. sah, a. s. m. h. m. talukder and c. a. meisner. 2006. permanent raised bed cultivation improves nitrogen and water use in rice-wheat cropping systems of south asia. 18th world science congress, usa. limon-ortega, a. l., k. d. sayre and c. a. francis. 2000a. wheat nitrogen use efficiency in a bed planting system in northwest mexico. agron. j. 92: 303-308. limon-ortega, a., k. d. sayre and c. a. francis. 2000b. wheat and maize yields in response to straw management and nitrogen under a bed planting system. agron. j. 92: 295-302. quayyum, m. a., j. timsina, m. a. h. s. jahan, r. a. begum and d. j. connor. 2002. grain yield and system productivity for wheat-mungbean-rice and wheat-maize rice sequences in northern bangladesh. thai j. agric. sci. 35: 51-62. 31 bed planting effect of rice and wheat in drought prone area rwc-cimmyt. 2003. addressing resource conservation issues in rice-wheat systems of south asia: a resource book. (rwc-cimmyt, new delhi, india). sayre, k. d., a. limon, and b. govaerts. 2005. experiences with permanent bed planting systems. in: roth, c. h., fischer, r. a., meisner, c. a. (eds.). evaluation and performance of permanent raised bed cropping systems in asia, australia and mexico, proceedings of a workshop, griffith, australia, 1-3 march 2005. aciar proceedings no. 121, pp.12-25. singh, y. 2003. crop residue management in rice-wheat system. 2003. in: addressing resource conservation issues in rice-wheat consortium for the indo-gangetic plains. cimmyt, new delhi, india, p.153. singh, h., and k. p. singh. 1995. effect of plant residue and fertilizer on grain yield of dryland rice under reduced tillage cultivation. soil till. res. 34: 115–125. tanaka, a. 1983. physiological aspects of productivity in field crops. in: potential productivity of field crops under different environments. irri, los banos, philippines, pp.61-80. talukder, a. s. m. h. m., c. a. meisner, m. j. kabir, a. b. s. hossain and m. harun-ur-rashid. 2004. productivity of multi-crops sown on permanent raised beds in the tropics. in: new direction for a diverse planet: handbook and abstracts for the 4th international crop science congress, brisbane, australia, 26 september 01 october 2004, p.173. talukder, a. s. m. h. m., m. a. sufian and c. a. meisner. 2002. rice, wheat and mungbean yields in response to n levels and management under a bed planting system. in: proceedings published in the 17th world congress of soil science, bangkok, thailand, v. 1, symposium no. 11, p.351. timsina, j. and d. j. connor. 2001. productivity and management of rice–wheat cropping systems: issues and challenges. field crops res. 69: 93-132. witt, c., k. g. cassman, d, c. olk, u. biker, s. p. liboon, m. i. samson and j. c. g. ottow. 2000. crop rotation and residue management effects on carbon sequestration, nitrogen cycling and productivity of irrigated rice systems. plant soil. 225: 263-278. yadvinder, s., s. bijay, and j. timsina. 2005. crop residue management for nutrient cycling and improving soil productivity in rice-based cropping systems in the tropics. adv. agron. 85: 269-407. yadvinder, s., s. bijay, j. k. ladha, c. s. khind and t. s. kera. 2006. effects of residue decomposition on productivity and soil fertility in rice-wheat rotation. soil sci. soc. amer. j. 68: 851-864. m. ilias hossain1, m. i. hossain2, m. r. i mondal3, m. k. sultan4, m. gathala5 and t. p tiwary5 key words: bed planting, cropping system, productivity, sustainable, drought microsoft word 1. baj-209_revised.docx bangladesh agron. j. 2016, 19(1): 1-10 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods of usg and prilled urea application m.k.a. bhuiyan1*, l. nahar1, m.m. mahbub1, r.shultana1, m.a.j. mridha1, m.a. rahman2 and m. kamruzzaman2 1agronomy division,2fmpht division, bangladesh rice research institute, gazipur, bangladesh corresponding author: bhuiyan072003@yahoo.com key words: usg and prilled urea applicator, nitrogen use efficiencies, brri dhan28 and brri dhan29 abstract an experiment was conducted at the bangladesh rice research institute (brri), gazipur during boro season of 2013-14 and 2014-15 to find out the nitrogen use efficiency and yield of boro rice var. brri dhan28 and brri dhan29 under four n management practices such as application of prilled urea using prilled urea applicator, application of usg (2.7gm) using usg applicator, broadcasting of prilled urea following three splits and a control (without urea). the experimental design was rcbd replicated thrice. brri dhan29 with urea broadcasted plots produced higher grain yield (7.38t ha-1) followed by brri dhan29 with usg application (6.65 t ha-1). hand broadcasting with urea fertilizer showed 15.38.5and 2.5, 9.89% higher grain yield than machine application of prilled urea and usg in brri dhan28 and brri dhan29, respectively. grain yield showed a significant quadratic response to n fertilization and significant linear response with total dry matter production in both the varieties. higher total n was uptake from urea broadcasted plots in brri dhan29 followed by urea broadcasted from brri dhan28. brri dhan29 with prilled urea applicator and brri dhan29 with usg treatment uptake intermediate nitrogen. n uptake in grain and total n uptake had a significant linear and quadratic response to n treatment in brri dhan28 and brri dhan29. nitrogen use efficiency was higher in brri dhan29 compared to brri dhan28. economic analysis showed that rice var. brri dhan28 and brri dhan29 with urea broadcast had the highest gross return of tk.145145.00 and tk. 158310.00 ha-1, respectively. however, the maximum cost (tk. 151131) was involved for brri dhan29 with urea broadcasting, while the minimum with no urea fertilizer application for both the varieties. the highest marginal rate of return (mrr) (tk.1146) was recorded from brri dhan28 with usg application using brri applicator. introduction nitrogen loss processes are due to ammonia volatilization, denitrification, runoff, seepage and leaching which can be improve nitrogen use efficiency for rice production. deep placement of nitrogen fertilizer into the anaerobic soil zone is a recognized effective method to reduce its volatilization loss from rice field. urea in the form of usg (urea super granule) has been proved to be superior to granular urea in all aspects. instead of normal does of 247 kg granular urea, only 160 kg ha-1 of usg was required (35% less) even to increase 20% rice yield (hoque et. al., 2013). depending on agro-climate and nitrogen use, deep-placed usg can save urea fertilizer up to 65% with a 33% increase in grain yields, and up to 50% with 15 to 20% yield increase over the same amount of split-applied nitrogen as prilled urea 2 bhuiyan et al. (fatema-tuz-zohra et al. 2013). it is reported that usg placement at 6-10 cm depth in wet land rice field can save 30% nitrogen compared to broadcasted prilled urea. hand placement of usg of 1.8 g to 2.7 g sizes into flood soil resulted in less loss of nitrogen, higher nitrogen recovery and higher yield than conventional nitrogen application method (hoque et al., 2013). usg is presently applied manually. it is placed at a depth of 8 to 10 cm of the soil at the center of 4 consecutive hills of 2 adjacent rows, which is labor intensive, cumbersome and very slow method, i.e. 0.07 to 0.12 ha/workday. unfortunately, farmers have not been able to be benefited from these findings, primarily because they have no suitable fertilizer placement equipment. recently brri has developed a prilled urea applicator, by which the fertilizer can be placed in a reduced zone of soil and saved about 30-35% without sacrificing grain yield. brri prilled urea applicator was designed and developed by considering plant spacing of 20 cm x 20 cm. it is also handy and work efficient. this study was therefore designed to analyze nitrogen use efficiency and yield performance of two popular boro rice varieties, brri dhan28 and brri dhan29, as affected by different sources of nitrogen and its application methods. materials and methods experimental site and soil the present study was conducted at the experimental field of bangladesh rice research institute (brri), gazipur situated at 23059´33´´ n and 90024´19´´ e at an elevation of 8.4 m from the mean sea level, and is characterized by sub-tropical climate. the soil of the field was clay loam of shallow brown terrace under madhupur tract (aez 28), the experimental field classified as a chhiata clay loam, hyperthermic vertic endoaquept. the chemical properties of the soil are presented in table 1. the soil of the experimental plot was neutral acidic in nature (ph =6.3) and poor in fertility status. the experiment was conducted at brri farm, gazipur during boro season of 2013-14 and 2014-15 to find out nues and response of brri dhan28 and brri dhan29 under four n management practices such as i) urea application by prilled urea applicator ii) usg (2.7 g) application by usg applicator, iii) hand broadcasting of prilled urea with three splits and iv) control (without urea). the experiment was conducted in factorial rcbd design with three replications. unit plot size was 6m x 4.8 m transplanted with 20cm x 20 cm spacing. brri recommended managements were followed for raising seedlings and for other intercultural operations. fertilizer tsp, mop, gypsum and zinc sulphate were added as basal. prilled urea and usg (2.7 g) by prilled urea applicator and usg applicator were applied 3 days after planting. prilled urea top dress were completed in three equal splits, at 15, 35 and 55 dat. thirtyeight -days old seedlings were transplanting on 16th and 18th august in 2013-14 and 2014-15, respectively. grain and straw samples were collected from each plot, oven dried at 65 °c and grains was measured by the standard micro-kjeldahl procedure (bremner and mulvaney, 1982). n uptake in grain and straw were calculated by following formulae. 100 )ha (kg yieldgrain grain in n %)ha (kg grain by uptake nitrogen -1 1  100 )ha (kg dstraw yiel straw in n %)ha (kgstraw by uptake nitrogen -1 1  3 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods agronomic efficiency, physiological efficiency, agro-physiological efficiency, apparent recovery efficiency, and utilization efficiency are calculated by using the formulas described by fageria et al. (1997); fageria and baligar (2001). data on yield and yield components were recorded at maturity. economic analysis was done to determine the efficiency of different treatments following the procedure of marginal rate of return (mrr) by cimmyt (1988). in a combined analysis of data, the interaction of year, n levels, and varieties was nonsignificant so, pooled analyses was done and means were compared by lsd test. results and discussion yield and yield character and total dry matter nitrogen and varieties showed insignificant effect on plant height, the individual effect of n on plant height was significant (p<0.01). in brri dhan28, usg treated plot produced the highest plant height, whereas urea broadcasting produced in brri dhan29. brri dhan29 produced higher panicle/m2 compared to brri dhan28where maximum panicle was produced by urea hand broadcasting treatment (358) followed by n application by prilled urea applicator (320). in brri dhan28 the maximum panicle was produced by urea hand broadcasting (298) followed by usg (288). thousand grain weight showed insignificant effect on nitrogen and variety interaction. brri dhan29 produced the highest grain yield (7.38t ha-1) in urea hand broadcasting plots followed by n application of usg applicator. in brri dhan28, similar results were observed. the lowest grain yield was observed from control plots in both varieties. figure 1 (a) showed grain yield showed a significant quadratic response to n fertilization in both the varieties. regression analysis showed highest grain yield of brri dhan28 and brri dhan29 was obtained with urea hand broadcasting treatment (124 kg n ha-1). singh et al. (1998) reported that maximum average grain yield 7.7 t ha-1 of lowland rice genotypes was obtained at 150 to 200 kg n ha−1. the relationship of grain yield with total dry matter yield showed highly significant and linear (figure 1 b). fageria and baligar (2001) reported that grain yield in lowland rice increased significantly and quadratically with increasing dry matter weight. grain harvest index (ghi) and n harvest index (nhi) individual effect of n and varieties on ghi was significant but their interaction was not significant. grain harvest index varied from 0.40 to 0.52 with an average value of 0.48 in brri dhan28 and 0.42 to 0.54 with an average value of 0.50 in brri dhan29 (table 4). figure 2 showed the kiniry et al. (2001) reported that the ghi varied greatly among cultivars, locations, seasons, and ecosystems, ranging from 0.35 to 0.62, indicating the importance of this variable for yield stimulation. nitrogen harvest index (nhi) showed insignificant in n and varieties but significant in interaction (table 5). the nhi values varied from 0.65 to 0.67, with an average value of 0.67 for brri dhan28 and from 0.64 to 0.88, with an average value of 0.66 for brri dhan29. fageria and barbosa filho (2001) reported that nhi values varied from 0.44 to 0.66 in lowland rice depending on genotypes. nitrogen concentration (%) and uptake in grain and straw 4 bhuiyan et al. the nitrogen and variety interactions in relation to grain n concentration (%) were not significant in brri dhan28 and brri dhan29 (table 5). but higher grain n was absorbed in brri dhan29 compared to brri dhan28. in brri dhan29 urea hand broadcasted plot observed higher grain n% followed by usg treated plots. but in brri dhan28 usg treated plots accumulated higher grain n% followed by urea hand broadcasted plots. in both the varieties urea hand broadcasted plots accumulated highest straw n. brri dhan29 accumulated average highest total n(1.58%) compared to n accumulated from brri dhan29 (1.54%) while control plot produced the lowest n%. n uptake in grain was highest in urea broadcasted plots (79.72 kg ha-1) followed by prilled urea applicator plots in brri dhan29 (table 5). but in brri dhan28 highest grain n was uptake from usg treated plots (71.63 kg ha-1) followed by urea hand broadcasted plots. in brri dhan29 maximum straw n was uptake from urea hand broadcasted plots followed by plots from prilled urea applicator plots. in brri dhan28 highest straw n was uptake from urea hand broadcasted plots followed by usg plots. highest total n was uptake from urea broadcasted plots in brri dhan29 followed by urea broadcasted plots from brri dhan28. n uptake in grain and total n uptake had a significant linear and quadratic response to n treatment from different sources in brri dhan28 and brri dhan29 (figure 3a, 3b). n uptake in grain also had a quadric relationship in brri dhan28 and in brri dhan29 (figure 3b). in both the varieties grain yield was significantly and linearly related with n uptake in grain (r2 = 0.96 and 0.99 for brri dhan29 and brri dhan28) and with total n uptake (r2 = 0.990and 0.999 for brri dhan29 and brri dhna28), respectively) (figure 3a and b), indicating that, in most cases, higher grain yield would be due to higher n uptake. likewise, an increase of the total n uptake implied an increase on the total dry matter production in both the varieties (figure 3c). almost 94.4 and 99.1% of the variation in total dry matter production was explained by n uptake in brri dhan29 and brri dhan28, respectively. pamela et al. (2009) reported n uptake in grain and total n uptake had a significant quadratic response to n fertilization but total n uptake increased significantly and linearly with n levels. nitrogen use efficiencies (nues) effect of n treatment on nues was significant in ae, pe, ue and pfp. the highest ae (49) was observed in brri dhan28 with n application from usg by usg applicator. the lowest ae (31) was found from brri dhan28 with n application from urea broadcasting. the highest pe (128) was observed in brri dhan29 with n application from usg by usg applicator while lowers with n application by broadcasting with three splits. the highest ape (84) was observed in brri dhan29 with n application from usg by usg applicator. the lowest ape was found from brri dhan29 and brri dhan28 with n application by broadcasting with three splits. singh et al. (1998) reported an agrophysiological efficiency of about 64 kg grain per kg of n uptake and agronomic efficiency of 37 kg grain per kg of n applied in 20 lowland rice genotypes. usg application by usg applicator and brri dhan28 produced the value (83) where as brri dhan28 with prilled urea applicator and usg with brri dhan29 found the lower recovery efficiency. the highest ue (108) was produced from brri dhan29 x usg application by usg applicator and the lowest from brri dhan29 urea broadcasted following three splits. pfp was highest in brri dhan29 x usg (89) application by usg applicator followed by brri dhan28 x usg (84) application by usg applicator treatment. the lowest pfp was observed from urea broadcasting in three splits in both brri dhan28 and brri dhan29. on average nitrogen use efficiencies was higher in brri dhan29 compared to brri dhan28. 5 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods economic analysis economics analysis was shown in tables 6, 7 and 8. table 6 indicated that the urea broadcasting with three splits with brri dhan29 showed the maximum gross return followed by urea broadcasting in brri dhan28. cost dominance analyses (table 7) showed that cost was highest (tk. 150831) for the treatment prilled urea broadcasting with brri dhan29 and lowest for control plots of both the varieties.. from table 8, it was observed that the treatment brri dhan28× prilled urea broadcasting and brri dhan28×prilled urea applicator were found cost dominated, where cost is more but gross margin is less than that of other treatments. the treatment brri dhan28 following usg application by usg applicator showed the highest mrr (tk.1146) and was more profitable than other n treatments as a result interaction of brri dhan28 x usg application by usg applicator was more profitable than other n management treatments. conclusion the findings of the study indicated that even though the highest grain yield was recorded from pu application by three splits, the nue was higher in brri dhan28 × usg application plots. usg application by applicator in both brri dhan28 and brri dhan29 saved 40% nitrogen with intermediate grain yield. economic analysis by mrr (marginal rate of return) indicated that brri dhan28 x usg application by usg applicator had the highest mmr (1144.86) over other treatments. however, some practical limitations related to accurate calibration and mechanical sophistication need to be resolved to improve further the efficiency of the applicator. table 1. initial soil chemical properties at 0-15 cm soil depth in the experimental plot soil properties value se (±) soil ph 6.3 0.19 organic matter 2.05% 0.27 total n content 0.09% 0.005 available phosphorus (p) 11.14 mg kg –1 (0.5 m nahco3 extracted) 0.094 exchangeable potassium (k) 0.18 meq/100 g soil (neutral 1.0 n nh4oac extracted) 0.018 available sulfur (s) 22 mg kg –1 [ca(h2po4)2 extracted] 1.76 available zinc (zn) 2.85 mg kg –1 (0.01n hcl extracted) 0.08 table 2. effect of varieties and nitrogen management on plant height, yield and yield contributing characters during boro season. brri, gazipur nitrogen management n rate (kg ha-1 plant height panicle m-2 grains panicle-1 1000 grain grain yield 6 bhuiyan et al. (n) (cm) weight (t ha-1) brri dhan28 control 0 87.54 207 75 20.61 2.59 pua 87 98.67 248 85 21.61 5.47 usg 75 102.12 288 87 23.24 6.30 pub 124 99.75 298 91 22.09 6.46 avg. 97.02 260 84 21.88 5.21 brri dhan29 control 0 92.70 205 76 21.27 3.11 pua 87 102.75 320 92 22.07 6.75 usg 75 99.06 317 89 21.79 6.65 pub 124 102.96 358 98 22.66 7.38 avg. 99.36 300 89 21.94 5.97 lsd(0.05) for n 5.45 10.61 4.32 ns 0.29 lsd(0.05) for v ns 7.50 3.05 ns 0.21 lsd(0.05) for n×v ns 15.00 ns ns 0.41 cv (%) 4.5 3.1 4.0 4.6 4.2 control= no urea, pua= prilled urea applicator, usg= urea super granule pub= urea broadcasting table 3. grain harvest index (ghi) and n harvest index (nhi) of brri dhan28 and brri dhan29 as influenced by n fertilization from different source and method of application grain harvest index n harvest index n source n rate kg ha-1 brri dhan28 brri dhan29 brri dhan28 brri dhan29 control 0 0.40 0.42 0.65 0.68 pua 87 0.51 0.52 0.67 0.65 usg 75 0.50 0.54 0.69 0.65 pub 124 0.52 0.53 0.66 0.64 average 0.48 0.50 0.67 0.66 lsd(0.05) for n 0.22 ns lsd(0.05) for v 0.16 ns lsd(0.05) for n×v ns 0.35 cv (%) 3.7 3.0 table 4. effect of varieties and nitrogen management on n (%) and uptake during boro season at brri, gazipur nitrogen (%) nitrogen uptake (kg ha-1) n management (n) n rate grain straw total grain straw total brri dhan28 control 0 0.84 0.46 1.31 22.14 18.02 40.16 7 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods pua 87 1.06 0.51 1.58 60.81 26.82 87.63 usg 75 1.12 0.50 1.63 71.84 30.41 102.26 pub 124 1.08 0.55 1.64 71.63 35.19 106.83 avg. 1.02 0.51 1.54 56.60 27.61 84.22 brri dhan29 control 0 0.91 0.42 1.33 29.85 18.02 47.87 pua 87 1.07 0.58 1.65 67.73 35.52 103.24 usg 75 1.03 0.54 1.57 61.56 28.11 89.67 pub 124 1.13 0.64 1.77 79.72 42.39 122.09 avg. 1.03 0.54 1.58 59.71 31.01 90.72 lsd(0.05) for n ns 0.43 0.10 8.37 4.35 9.74 lsd(0.05) for v ns 0.30 ns ns 3.07 ns lsd(0.05) for n×v ns 0.61 ns ns 6.15 13.77 cv (%) 6.9 6.6 5.2 11.60 12.0 9.0 table 5. n use efficiencies of different n sources and method of application in variety and nitrogen interaction during boro 2014 at brri, gazipur nitrogen use efficiencies n manage ment n rate ae (kg ha-1) pe (kg ha-1) ape (kg ha-1) are (%) ue (kg ha1) pfp (kg ha-1) brri dhan28 pua 87 33 102 67 55 72 63 usg 75 49 106 60 83 63 84 pub 124 31 95 58 54 56 52 avg. 38 101 62 64 64 66 brri dhan29 pua 75 42 110 65 64 71 78 usg 124 47 128 84 56 108 89 pub 0 34 91 58 60 53 60 avg. 41 110 69 60 77 76 lsd(0.05) for n 5.10 15.72 ns ns 24.69 3.70 lsd(0.05) for v ns ns ns ns ns 2.02 lsd(0.05) for n×v ns ns ns 19.56 ns 5.24 cv (%) 10.0 11.6 18.3 17.4 27.2 2.8 ns= not significant at the 0.05 probability level. ae= agronomic efficiency, pe= physiological efficiency, ape= agro-physiological efficiency, are= apparent recovery efficiency, ue= utilization efficiency, pfp= partial factor productivity table 6. cost return analysis of variety and management variety × n management treatment variable cost (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) brri dhan28×n0 0 65956 65956 brri dhan28×pua 4990 126676 121686 8 bhuiyan et al. brri dhan28×usg 4782 140860 136078 brri dhan28×pub 7438 145145 137707 brri dhan29×n0 0 81270 81270 brri dhan29×pua 4823 141195 136372 brri dhan29×usg 4900 141696 136796 brri dhan29×pub 7479 158310 150831 table 7. cost dominated treatment (variety x n fertilizer) gross margin (tk. ha-1) treatments variable cost (tk. ha-1) cost dominated treatment 150831 brri dhan29× pub 7479 137707 brri dhan28× pub 7438 * 136796 brri dhan29×usg 4900 136372 brri dhan29×pua 4823 136078 brri dhan28×usg 4782 121686 brri dhan28×pua 4990 * 81270 brri dhan29×n0 0 65956 brri dhan28×n0 0 table 8. marginal rate of return of the applied (variety x n fertilizer) gross margin (tk. ha-1) treatments variable cost (tk. ha-1) marginal variable cost (tk ha-1) marginal gross margin (tk. ha-1) marginal rate of return 151131 brri dhan29× pub 7479 2579 14035 544 136806 brri dhan29×usg 4900 77 424 551 136335 brri dhan29×pua 4823 41 294 717 136218 brri dhan28×usg 4782 4782 54808 1146 81470 brri dhan29×n0 0 15314 66083 brri dhan28×n0 0 9 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods fig.1. relationship between grain yield and n rate obtained from different sources (fig. 1a) and total dry matter and grain yield of rice varieties brri dhan28 and brri han29 (fig. 1b), ∗∗ significant at the 0.05 probability level fig. 2. relationship between harvest index and grain yield 10 bhuiyan et al. fig. 3. relationships between (a) grain n uptake and grain yield, (b) total n uptake and grain yield, and (c) total n uptake and total dry matter production of rice varieties brri dhan28 and brri dhan29. ∗∗ significant at the 0.05 probability level references bremner, j. m. and c. s. mulvaney. 1982. total nitrogen. in: a. l. page, r. h. miller, d. r. keeny (eds.). methods of soil analysis. american society of agronomy and soil science society of america, madison, usa. pp. 1119-1123. cimmyt. 1988. from agronomic data to farmer recommendations: an economics training manual. completely revised edition. centro internacional de mejoramiento de maize y trigo (cimmyt), mexico d.f., mexico. fageria, n. k., v. c. baligar and c. a. jones. 1997. growth and mineral nutrition of field crops. 2nd ed.; marcel dekker, inc.: new york. fageria, n. k. and v. c. baligar. 2001. lowland rice response to nitrogen fertilization. commun. soil sci. plant 32: 1405-1429. 11 yield response and nitrogen use efficiency of boro rice varieties as affected by different methods fageria, n. k. and m. p. barbosa filho. 2001. nitrogen use efficiency in lowland rice genotypes. commun. soil sci. plant 32: 2079-2090. fatema-tuz-zohra, r. ali, m. salim and m. a. kader. 2013. effect of urea super granules on the performance of transplant aman rice. j. agrofor. environ. 7(1): 49-52. hoque, m. a., m. wohab, a. m. hossain, k. k. saha and m. s. hassan. 2013. improvement and evaluation of bari usg applicator. agric. eng. int.: cigr j. 15(2): 87-94. kiniry, j. r., g. mccauley, y. xie and j. g. arnold. 2001. rice parameters describing crop performance of four u. s. cultivars. agron. j. 93: 1354-1361. pamela, a., c. bonomelli and f. meza. 2009. nitrogen application in irrigated rice grown in mediterranean conditions: effects on grain yield, dry matter production, nitrogen uptake, and nitrogen use efficiency. j. plant nutr. 32: 1574-1593. singh, u., j. k. ladha, e. g. castillo, g. punzalan, a. irol-padre and m. duqueza. 1998. genotypic variation in nitrogen use efficiency in medium and long duration rice. field crops res. 58: 35-53. bangladesh agron. j. 2015, 18(2): 31-38 midday drop of relative leaf water content to drought tolerance in soybean j.a. chowdhury1, m.a.karim2, q. a. khaliq2, m.s.a. khan1, s. k. paul1 and a.u. ahmed3 1agronomy division, bangladesh agricultural research institute, gazipur-1701 2department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 3plant pathology division, bangladesh agricultural research institute, gazipur-1701 corresponding author: jasminedaisy.bari@gmail.com key words: relative water content, midday drop of rwc, soybean abstract an experiment was conducted in a venylhouse of bangabandhu sheikh mujibur rahman agricultural university during september to december 2012 to determine the effect of midday drop of relative water content (rwc) on drought tolerance of soybean genotypes. four soybean genotypes viz. shohag, bari soybean-6, bd2331 and bgm2026 were used in the study. plants were grown in pots under stress and control condition. a marked difference in rwc between morning and midday was observed both in stressed and control plants. bari soybean-6 showed higher rwc than rest of the genotypes and bgm2026 showed the lowest at all growth stages. the reduced rwc of bari soybean-6 under water stress at vegetative, flowering and pod developing stages were 11.35, 13.52 and 15.04% at 1.00 pm as compared to control, respectively. the reduced rwc of bgm2026 at vegetative, flowering and pod developing stages were 18.99, 20.64 and 23.05% at 1.00 pm, respectively. in stressed plants, midday drop of relative water content was minimal in bari soybean-6 (8.97%) and maximum in bgm2026 (17.89%) at 1.00 pm. under water stress condition bari soybean-6 gave the highest seed yield (5.23 g plant-1) and bgm2026 the lowest (3.21 g plant-1) which might be attributed to the drastic reduction in 100-seed weight of rwc in the variety bgm2026 due to the significant reduction in rwc in this variety. considering the midday drop of rwc and seed yield, it may be concluded that bgm2026 is susceptible and bari soybean-6 is drought tolerant among the genotypes. introduction soybean is an important grain legume. it plays an important role in supplying protein and oil needed by humans. water deficit adversely affects many physiological processes related to water use efficiency in soybean, thus leading to a decrease in plant productivity (hamayun et al., 2010). water stress has been found to decrease leaf water potential, relative water content and exudation rate and also to influence leaf anatomical characteristics and photosynthetic parameters (omae et al., 2005; omae et al., 2007). so, there is a general consensus that water economy is very critical to plant growth and development. the drought stress mainly causes lowering in some agronomic traits of soybean such as pod setting ratio, early pod abscission and finally leads to lower productivity (suzuki et al., 2001; tsukaguchi et al., 2003). among several methods used to characterize internal plant water status under drought conditions, relative water content (rwc) is an integrative indicator (parsons and howe, 1984), and was used successfully to identify drought resistance in french bean (rosales-serna et al., 2004; and mustard (mondal and paul, 1992). cultivars with a smaller midday drop in leaf water content set more pods than the cultivars showing a larger midday drop in leaf water content (omae et al., 2004; omae et al., 2005). during plant development, drought stress significantly reduced rwc values from 88 to 45% (siddique et al., 1999). soybean yield enhancement requires selection of tolerant and compatible cultivar in dry climate and low water environment (maleki et al., 2013). therefore, the present experiment was undertaken to determine the effect of midday drop of relative water content (rwc) on drought tolerance of soybean genotypes. 32 chowdhury et al. materials and methods a pot experiment was conducted in a vinyl house at bangabandhu sheikh mujibur rahman agricultural university during september to december 2012. three relatively water stress tolerant (shohag, bari soybean-6 and bd2331) and one susceptible (bgm2026) genotype selected from the previous experiment were used in this study to determine the effect of midday drop of relative water content (rwc) on drought tolerance of soybean genotypes at vegetative, flowering and pod development stages. seeds of tolerant genotypes and susceptible genotypes were sown in plastic pots, 30 cm in height and 24 cm inner diameter. the soil of the pot was filled with mixture of soil and cowdung at a ratio of 4:1. pot contained 12.0 kg of soil which was equivalent to 9 kg oven dry soil with 28% moisture at field capacity (fc). soil used in the pot was sandy loam. the soil of the pot was fertilized uniformly with 24-30-60-15 kg npks per hectare, respectively. six seeds pot-1 were sown on 3 september, 2012. after seedling establishment two uniform and healthy plants pot-1 were allowed to grow. drought stress (water stress; 50% water of the fc) and non-stress (control) treatments were applied at 21 days after emergence (dae) and maintained throughout the growing seasonthe pots were arranged in a completely randomized design (factorial) with four replications. general management practices were applied for all the treatments equally. relative water content, midday drop of relative water content, yield contributing characters and yields were recorded. rwc and midday drop of rwc were measured by following methods. relative water content (rwc) of leaves was measured at vegetative, flowering and pod development stages of each genotype at 8:00 am and 1:00 pm. fully developed 3rd leaf from the top was used for rwc measurement. immediately after cutting, leaves were sealed within plastic bags and kept in ice box and quickly transferred to the laboratory. the fresh weight of leaves from each treatment was recorded just after removal. turgid weight (tw) was obtained after soaking leaves in distilled water in beakers for 24 hours at room temperature (about 20ºc) and under low light condition of the laboratory. after soaking, leaves were quickly and carefully blotted dried with tissue paper in preparation for determining turgid weight. dry weight (dw) of the leaf was obtained after oven drying the leaf samples for 72 hour at 70ºc. rwc was calculated using the formula of schonfeld et al. (1988): rwc (%) = (fw – dw) / (tw – dw) x 100 where, fw = fresh weight, dw = dry weight, tw = turgid weight midday drop of rwc: the difference of rwc at mid-day (1:00 pm) to that in the morning (8:00 am) was calculated for mid-day drop of rwc. the data were analyzed by mstat-c statistical package program and treatments means were compared by least significant difference (lsd) test (gomez and gomez, 1983). functional relationships among different parameters as affected by water stress were established through correlation and regression analyses by using excel program. results and discussion relative water content rwc values of four genotypes at three different stages are shown in figs 1, 2 and 3. water stress significantly reduced rwc at two sampling times (8:00 am and 1:00 pm) across the genotypes at different growth stages in all the four soybean genotypes studied. at 8.00 am, rwc of water stressed plants of shohag decreased by 9.47, 9.99 and 12.26%, bari soybean-6 decreased by 8.92, 9.96 and 11.78%, bd2331 decreased by 8.79, 10.32 and 13.16%, and bgm2026 decreased by 13.74, 14.17 and 16.04% from control plants at vegetative, flowering and pod development stages, respectively. at 1.00 pm, rwc of water stressed plants decreased by 11.99, 13.74 and 15.29% in shohag, 11.35, 33 midday drop of relative leaf water content to drought tolerance in soybean 13.52 and 15.04% in bari soybean-6, 10.8, 14.9 and 16.04 % in bd2331 and 18.99, 20.64 and 23.05 % in bgm2026 at vegetative, flowering and pod development stages, respectively. plants grown under water stress conditions showed a lower rwc than those grown under non stress conditions. relative water content was higher in the morning, while decreased at noon. several researchers reported that rwc of different crops was the highest in the morning and thereafter gradually decreased (pual and aman, 2000; omae et al., 2005. bari soybean-6 had higher rwc than the rest of genotypes whereas genotype bgm2026 had the lowest rwc at all the three growth stages under both non-stress and stress condition. the rwc of all the genotypes fell at noon, possibly due to higher evaporation resulting from increased temperature and light intensity. midday drop of relative water content the water stress reasonably affected the mid-day drop of rwc (fig. 1-3). the difference of rwc between watered and water stressed plants was clear in the midday drop of rwc of the genotypes. in both watered and drought-stressed plant it was minimal in bari soybean-6 and the greatest in bgm2026. irrespective of genotypes, the higher value was recorded in the plants under water stress at all the growth stages. the midday drops of rwc at non-stressed plants were 4.49, 4.86 and 6.08 % in shohag, 4.03, 5.06 and 5.47 % in bari soybean-6, 4.72, 5.70 and 8.38 % in bd2331 and 5.43, 7.93 and 10.42 % in bgm2026 at vegetative, flowering and pod development stages, respectively. in water stressed plants the midday drops of rwc were 7.10, 8.83 and 9.33 % in shohag, 6.59, 8.46 and 8.97 % in bari soybean-6, 6.82, 8.92 and 11.41 % in bd2331and 11.19, 14.87 and 17.89 % in bgm2026 at vegetative, flowering and pod development stages, respectively. in well watered plants, the mid-day drop of rwc was minimal in bari soybean-6 at vegetative and pod development stage while in shohag at flowering stage under water-stressed plants, it was minimal in bari soybean-6 followed by shohag and bd2331 irrespective of growth stages. the maximum rwc was recorded in bgm2026 under both the water regimes. omae et al. (2005) reported that tolerant cultivars had the lowest mid-day drop of rwc as compared to susceptible cultivars. they suggested that mid-day drop of rwc might be used as a screening marker for drought tolerance of phaseolus vulgaris. 34 chowdhury et al. fig. 1. relative water content (rwc) and mid-day drop of rwc in soybean genotypes under non-stress and water stress conditions at vegetative stage. vertical bar represent lsd value at 5% level of significant. fig. 2. relative water content (rwc) and mid-day drop of rwc in soybean genotypes under nonstress and water stress conditions at flowering stage. vertical bar represent lsd value at 5% level of significant. fig. 3. relative water content (rwc) and mid-day drop of rwc in soybean genotypes under nonstress and water stress conditions at pod development stage. 35 midday drop of relative leaf water content to drought tolerance in soybean vertical bar represent lsd value at 5% level of significant. yield components and seed yield moisture levels affected significantly the yield and yield contributing characters of soybean genotypes. water stress significantly reduced the number of pod plant-1 of all the genotypes studied (table 1). the maximum t pods plant-1 was found in bgm2026 (69.18) followed by bari soybean-6 (54.41), shohag (51.85) and the lowest in bd2331 (51.18) under non-stress condition. on the contrary, the number of pods plant-1 was the maximum in bari soybean-6 (29.37), followed by shohag (27.92), bd2331 (25.34) and the lowest in bgm2026 (21.34) under water stress situation. the genotype bgm2026 was the most affected genotype by the water stress with 69.51% reduction of pods plant-1; whereas,46% in bari soybean-6,. shohag and bd2331 showed 46.15 and 50.48% , respectively. cultivars showing a smaller mid-day drop in leaf water content set more pods than the cultivars showing a large mid-day drop in leaf water content (omae et al., 2004). water stress also significantly reduced seeds number pod-1 of all the soybean genotypes studied (table 1). genotype bgm2026 produced significantly highest seeds number pod-1 under non-stress condition and the lowest under stress condition. shohag produced the highest number of seeds pod-1 under stress condition. this character was reduced by water stress in bgm2026 by 19.45% but in shohag it was only 5.02%. hundred seed weight was significantly decreased by the water stress in all the genotypes (table 2). the highest seed weight was found in bari soybean-6 and the lowest in bgm2026 in both the conditions. reductions in 100-seed weight ranged from 3.11 to 15.97% under water stress conditions compared to the non-stressed conditions. the reduction of 100-seed weight was the highest in the genotypes bgm2026 (15.97%). the result is in consistent with other studies, which indicated that water stress drastically reduced the number of pods plant-1 as compared to 100-seed weight (lizana et al., 2006 and nun-ez-barrios et al., 2005). crop yield is mainly a function of various components such as number of pods plant-1, number of seeds pod-1 and seed size. thus, the seed yield was reduced drastically as a consequence of reduced pods plant-1, seeds pod-1 and 100-seed weight. seed yield ranged from 8.69 to 10.32 g plant-1 and 3.21 to 5.23g plant-1 under non-stress and water stress condition (table 2), respectively. among the genotypes the highest seed yield was recorded from bari soybean-6 and the lowest from bd2331 under non-stress condition. under water stress condition bari soybean-6 gave the highest yield (5.23 g plant-1) and bgm2026 the lowest (3.21 g plant-1). yield reduction was ranged from 49.32 to 68 46%. the highest reduction (68.46%) in seed yield was observed in bgm2026 and the reduction of shohag, bari soybean-6 and bd2331 showed 50, 49.32 and 50.58%, respectively. table. 1. pod number plant-1and seed number pod-1 of soybean genotypes under nonstress and water stress conditions pod plant-1 (no.) seeds pod-1 (no.) genotypes nonstress water stress % reduction nonstress water stress % reduction shohag 51. 85 27.92 46.15 2.09 2.08 5.02 bari soybean-6 54.41 29.37 46 2.12 1.92 9.43 bd2331 51.18 25.34 50.48 2.1 1.85 11.9 bgm2026 69.18 21.34 69.15 2.21 1.78 19.45 s ** ** g 4.73 0.05 lsd(0.05) s x g 6.69 0.07 cv (%) 9.24 3.28 s=stress, g=genotypes, **significant at 1% level 36 chowdhury et al. number of seeds pod-1 and weight of 100-seed also played an important role in lowering the seed yield. reduction in the seed yield by water stress was also reported for soybean (liu et al., 2003) and phaseolus vulgaris (choudhury 2009; islam et al., 2004; omae et al., 2005; lizana et al., 2006). table 2. hundred seed weight and seed yield plant-1 of soybean genotypes under non-stress and water stress conditions 100-seed weight (g) seed yield plant-1 (g) genotypes non-stress water stress reduction (%) nonstress water stress reduction (%) shohag 13.94 13.06 6.31 9.4 4.7 50 bari soybean-6 14.13 13.69 3.11 10.32 5.23 49.32 bd2331 13.61 12.69 6.75 8.69 4.29 50.58 bgm2026 7.01 5.89 15.97 10.18 3.21 68.46 s * ** g 0.97 ns lsd(0.05) s x g ns ns cv (%) 6.73 1.92 s=stress, g=genotypes, ns=not significant, *significant at 5% level, **significant at 1% level the mid-day drop of rwc negatively correlated with seed yield plant-1 and number of pods plant-1 (figs. 1 and 2). simple linear regression between midday drop of rwc and seed yield suggested that the genotype with a smaller mid-day drop of rwc produced a larger number of pods plant-1 and consequently had higher yield as compared to others. fig. 1. functional relationship between mid-day drop of relative water content (rwc) with number of pod plant-1 37 midday drop of relative leaf water content to drought tolerance in soybean y = -0.531x + 12.32 r² = 0.544 0 2 4 6 8 10 12 0 5 10 15 20 se ed y ie ld p la nt -1 (g ) midday drop of rwc (%) fig. 2. functional relationship between mid-day drop of relative water content (rwc) with seed yield plant-1 conclusion considering the midday drop of relative water content, yield contributing characters and seed yield it may be concluded that among the genotypes bari soybean-6, shohag and bd2331 were drought tolerant and bgm26026 was susceptible. references aguirre, j. f., l. p. j. ruiz, j. kohashi-shibata, c. trejo-lopez and j. a. acosta-gallegos. 1999. morphological observations in the leaf surface of phaseolus vulgaris l. and their possible relationship to stomotal response. ann. rep. bean improv. coop. 42: 75-76. choudhury, a. k. 2009. water stress tolerance of french bean (phaseolus vulgaris l.). ph. d. dissertation. department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur-1706. bangladesh. hamayun m., s. a. khan, z. k. shinwari, a. l. khan, n. ahmed, and i. j. lee. 2010. effect of poly ethylene glycol induced drought stress on physio-hormonal attributes of soybean. pak. j. bot. 42: 977-986. iannucci, a., a. rascio, m. russo, n. d. fonzo and p. martineiello. 2000. physiological responses to water stress following a conditioning period in berseem clover. plant soil 223: 217-227. lizana, c., m. wentworth, j. p. mart-ynez, d. villegas, r. meneses, e. h. murchic, c. pastenses, b. lercari, p. vernieri, p. horton and m. pinto. 2006. differential adaptation of two varieties of common been to abiotic stress. i. effects of drought on yield and photosynthesis. j. expt. bot. 57: 685-697. maleki a., a. naderi, r. naseri, a. fathi, s. bahamin and r. maleki. 2013. physiological performance of soybean cultivars under drought stress. bulletin of environment, pharmacology and life science. 2: 38-44. mondal, r. k. and n. k. paul. 1992. effect of irrigation on growth and some physiological characters of mustard (brassica juncea l.). bangladesh j. agric. res. 17: 29-36. nun-ez-barrios, a., g. hoogenboom, and d. c. nesmith. 2005. drought stress and the distribution of vegetative and reproductive traits of bean cultivar. sci. agric. (piracicaba, braz). 62: 18-22. 38 chowdhury et al. omae, h., a. kumar, y. egawa, k. kashiwaba and m. shono. 2004. leaf water status of two snap bean (phaseolus vulgarid l.) cultivars differing in tolerance to high temperature sress. jpn. j. trop. agric. 48: 5-6. omae, h., a. kumar, k. kashiwaba and m. shono. 2007. assessing drought tolerance of snap bean (phaseolus vulgaris) from genotypic differences in leaf water relations, shoot growth and photosynthetic parameters. plant prod. sci. 10: 28-35. omae, h., a. kumar, y. egawa, k. kashiwaba and m. shono. 2005. midday drop of leaf water content to drought tolerance in snap bean (phaseolus vulgarid l.). plant prod. sci. 8: 465-467. paul, n. k. and r. aman. 2000. genotypic variation in physiological characters and grain yield of wheat under low soil moistures. ann. bangladesh agric. 10: 195-201. parsons, l. r. and t. k. howe. 1984. effects of water stress on the water relatins of phaseolus vulgaris and the drought resistant phaseolus acutifolius. physiol. plant. 60: 197-202. rosales-serna, r., j. kohashi-shibata, j. a. acosta-gallegos, c. trejo-lopez, j. ortiz-cerceres and j. d. kelly. 2004. biomas distribution, maturity acceleration and yield in drought-stressed common bean cultivars. field crops res. 85: 203-2011. schonfeld, m. a., r. c. johnson, b. f. carver, d.w. mornhinweg. 1988. water relations in winter wheat as drought resistance indicators. crop sci. 28: 526-531. siddique, m. r. b., a. hamid, and m. s. islam. 1999. drought stress effects on photosynthetic rate and leaf gas exchange of wheat. bot. bull. acad. sci. 40: 141-145. suzuki, k., t. tsukaguchi, h. takeda and y. egawa. 2001. decrease of pollen stainability of snap bean at high temperatures and relationship to heat tolerance. j. amer. scos. hort. sci. 126: 571-574. tsukaguchi, t., y. kawamitsu, h. takeda, k. suzuki and y. egawa. 2003. water status of flower buds and leaves as affected by temperature in heat-tolerant and heat-sensitive cultivars of snap bean (phaseolus vulgaris l.). plant prod. sci. 6: 24-27. bangladesh agron. j. 2015, 18(1): 99-111 effect of poultry manure incorporated with nitrogenous and sulfur fertilizer on the growth, yield, chlorophyll and nutrient contents of rice var. brri dhan33 d. sarker1, s.mazumder2, s.kundu3, f.akter4, and s.k.paul5 1department of agricultural chemistry, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2sher-e-bangla nagar adorsha mohila college, dhaka-1207, bangladesh 3planning and evaluation division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh 4planning and evaluation division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh 5agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. key word: poultry manure, nitrogen, sulfur, rice var. brri dhan33. abstract the experiment was conducted in the farm of sher-e-bangla agricultural university, dhaka, bangladesh during the period from august to december 2012 to study the effect of various combinations of organic manure and inorganic fertilizer on the growth, yield, chlorophyll and nutrient content of rice var. brri dhan33. the treatment consists of t1: 100% inorganic fertilizer (recommended dose) + 5 ton poultry manure (pm) /ha , t2: 75 % n of recommended dose + 5 ton pm /ha, t3: 50 % n of recommended dose + 5 ton pm /ha, t4: 25 % n of recommended dose + 5 ton pm /ha, t5: 75 % s of recommended dose + 5 ton pm /ha, t6: 50 % s of recommended dose + 5 ton pm /ha, t7: 25 % s of recommended dose + 5 ton pm /ha, t8: 100% inorganic fertilizer and t9: 5 ton pm /ha. significant variation was found in growth and yield parameters as well as in chlorophyll content and nutrient content of aman rice. the most of the growth parameters ( plant height, leaf length and diameter, leaf number and total tiller plant-1) results were found better in 100% inorganic fertilizer + 5 ton pm ha-1 which was statistically similar with 75 % of recommended dose of s + 5 ton pm ha-1, 75 % of recommended dose of n + 5 ton pm ha-1and followed by 50 % of recommended dose of s + 5 ton pm ha-1,respectively while the lowest from 5 ton/ha pm treatment. on the other hand, significantly higher chlorophyll “a”, “b” and total chlorophyll content were recorded in 100% inorganic fertilizer + 5 ton pm ha1and it was closely followed by 75 % of recommended dose of n + 5 ton pm ha-1 and lowest in 5 ton pm ha-1. number of effective tillers plant-1, panicle length, number of rachis plant-1, filled grain plant-1 and fresh weight of plant were highest in 100% inorganic fertilizer + 5 ton pm /ha and it was either statistically similar or closely followed by 75 % of recommended dose of s + 5 ton pm ha-1. higher grain yield (4.18 t ha-1) was recorded in t1 which was statistically similar with t5 (4.13 t ha-1) whereas lowest grain yield (3.67 t ha-1) was from sole pm. similarly, n content in grain and n, k content in straw were also showed similar trend. s content in grain and p, s content in straw were higher in 75 % of recommended dose of s + 5 ton pm /ha compared to other fertilizer treatments. lowest n and s content in grain and n, p, k, s content in straw were found from the treatment using poultry manure only. introduction rice is intensively cultivated in bangladesh covering about 80% of arable land. rice alone constitutes 95% of the food grain production in bangladesh. unfortunately, the yield of rice is low considering the other rice growing countries like south korea and japan where the average yield is 7.00 and 6.22 t ha-1, respectively (fao, 1999. a suitable combination of 100 sarker et al. organic and inorganic sources of nutrients is necessary for sustainable agriculture that can ensure food production with high quality. nambiar (1991) views that integrated use of organic manure and chemical fertilizers would be quite promising not only in providing greater stability in production, but also in maintaining better soil fertility. meelu and singh (1991) showed that 4 t ha-1 poultry manure along with 60 kg n/ha as urea produce grain yield of crop similar to that with 120 kg n/ha as urea alone. depleted soil fertility is a major constrain to higher crop production in bangladesh. applications of both chemical and organic fertilizers need to be applied for the improvement of soil physical properties and supply of essential plant nutrients for higher yield. (sarvanan et al., 1987).rice is very responsive to n fertilization and high yield potential of modern varieties cannot be realized without n supply to the plant during the entire growing season. nitrogen has quickest and remarkable effect on cereals production (brady, 1999). sulphur, one of the most important nutrients for all plants and animals, is considered as the fourth major nutrient after nitrogen, phosphorous and potassium for agricultural crop production. it is involved in chlorophyll formation, activation of enzymes and is a part of vitamins biotin and thiamine (b1) (hegde and sudhakara babu, 2007). poultry manure is superior to the other farmyard manure as a source of nitrogen supply. all the nitrogen in poultry manure is not in available from initially. hence, soils treated with poultry manure are less susceptible to nitrogen leaching since the vegetables grown utilize nitrate as they are produced (maynard, 1984). considering the above facts, the experiment was under taken to find out the response of pm along with chemical fertilizers for rice var. brri dhan33. materials and methods the experiment was conducted in the farm of sher-e-bangla agricultural university, dhaka1207, bangladesh during the period from august to december 2012. the experimental area is located at 23.41' n and 90.22' e latitude and at an altitude of 8.6 m from the sea level. the soil of the experimental field belongs to the tejgaon series under the agro-ecological zone, madhupur tract (aez28) and the general soil type is deep red brown terrace soils. the experiment was laid out in randomized complete block design (rcbd) with three replications. rice var. brri dhan33 was used in the experiment. the treatments were: t1=100% inorganic fertilizer (recommended dose) + 5 ton poultry manure/ha, t2=75 % n of the recommended dose + 5 ton poultry manure/ha, t3= 50 % n of the recommended dose + 5 ton poultry manure/ha, t4= 25 % n of the recommended dose + 5 ton poultry manure/ha, t5: 75 % s of the recommended dose + 5 ton poultry manure/ha, t6: 50 % s of the recommended dose + 5 ton poultry manure/ha, t7: 25 % s of the recommended dose + 5 ton poultry manure/ha, t8: 100% inorganic fertilizer, t9: 5 ton poultry manure/ha. the amounts of n, p, k, s and zn fertilizers required per plot were calculated as per the treatments. poultry manure was used @ rate of 5 ton/ha and was applied before four days of final land preparation. forty days old seedlings of brri dhan33 were transplanted on 21st august, 2012. all other intercultural operation was done as per requirement. the crop was harvested at full maturity when 80-90% on 27 december, 2012. the data collected on different parameters were statistically and the mean differences among the treatments were compared by duncan’s multiple range test (dmrt) test at 5% level of significance. nitrogen was determined by micro kjeldahl method (jackson, 1973). amount of chlorophyll were calculated using the following equations/ formula (witham, 1986): chlorophyll a (mg/g) = [12.7 (od663) 2.69 (od645)] v/1000w chlorophyll b (mg/g) = [22.9 (od645) 4.68 (od663)] v/1000w chlorophyll a+b (mg/g) = [20.2(od645) – 8.02 (od663)] v/1000w 101 effect of poultry manure incorporated with n and s fertilizer on the growth of rice where, od = optical density regarding of the chlorophyll extract at the specific indicated wavelength (645 and 663nm) v = final volume of the 80% acetone chlorophyll extract (ml) w = fresh weight in gram of the tissue extracted results and discussion the results of different growth parameters, chlorophyll contents, yield attributes, yield and nutrient concentrations in the straw and grains of rice were found significant and summarized below plant height the data on plant height of rice at different growth stages as influenced by organic and inorganic fertilizers are presented in fig.1.the plant height at 30 days after transplanting (dat) differed significantly due to different treatments where higher plant height (59.4 cm) was recorded in t1 and it was statistically similar with t5 ( 57.6 cm) and t8 (57.6 cm). lowest plant height at 30 dat (48.4 cm) was found from t9. the plant height at 60 days after transplanting (dat) also differed significantly due to different treatment where maximum plant height (103.6 cm) was recorded in t5 and it was closely followed by t1 (100.1 cm) and t2 (99.5 cm). lowest plant height at 60 dat (91.4 cm) was found from the treatment using sole poultry manure. at harvest, plant height also showed significant where maximum plant height (104.6 cm) was recorded in t5 and it was closely followed by t1 (102.2 cm) and t2 (101.0 cm). lowest plant height at harvest (93.2 cm) was found from the treatment using sole poultry manure. the results showed that combination of organic and inorganic fertilizers significantly increased the plant height than sole use of inorganic fertilizer and then that of organic manure. combination of organic and inorganic fertilizers was found better by umanah et al. (2003) in upland rice and channabasavanna (2003) in wetland rice than only inorganic fertilizers. fig. 1(a). effect of different combinations of organic and inorganic fertilizer on plant height of brri dhan33 (30 dat) 102 sarker et al. fig. 1(b). effect of different combinations of organic and inorganic fertilizer on plant height of brri dhan33 (60 dat) fig. 1(c). effect of different combinations of organic and inorganic fertilizer on plant height of brri dhan33 (at harvest) number of leaves the data on number of leaves plant-1 of rice at different growth stages as influenced by organic and inorganic fertilizers fig. 4 (a, b & c). the number of leaves plant-1 at 30, 60 dat and at harvest differed significantly due to different treatments. significantly higher number of leaves plant-1 (4.1) was recorded in t1 which was statistically similar to t2 (3.9). lowest number of leaves plant-1 at harvest (3.41) was found from the treatment using only poultry manure .combination of organic and inorganic fertilizers significantly increased the number of leaves plant-1 than sole. ndaeyo et al. (2008) showed that higher npk (15:15:15) fertilizer significantly increased number of leaves. 103 effect of poultry manure incorporated with n and s fertilizer on the growth of rice fig. 2(a). effect of different combinations of organic and inorganic fertilizer on number of leaves plant-1 of brri dhan33 (30 dat) fig. 2(b). effect of different combinations of organic and inorganic fertilizer on number of leaves plant-1 of brri dhan33 (60 dat) 104 sarker et al. fig. 2 (c). effect of different combinations of organic and inorganic fertilizer on number of leaves plant-1 of brri dhan33 (at harvest) number of effective and non-effective tillers at harvest the data on number of effective and non-effective tillers tillers plant-1 of rice at harvest as influenced by organic and inorganic fertilizers in fig. 6 (a & b). the highest number of effective tillers plant-1 (18) was recorded in t1 while lowest number of effective tillers plant-1 at harvest (12) using sole poultry manure .the number of non-effective tillers plant-1 at harvest also differed significantly due to different treatments. highest number of non-effective tillers plant-1 (5) was recorded in t8 and lowest number at harvest (2) from the treatment using t5 .combination of organic and inorganic fertilizers significantly increased the number of effective and decreased the number of non-effective tillers plant-1 than sole use of inorganic fertilizer and than that of organic manure. amin et al. (2004) found that increased fertilizer dose of npk increase number of total tillers plant-1. fig. 3(a). effect of different combinations of organic and inorganic fertilizer on number of effective tillers plant-1 of brri dhan33 105 effect of poultry manure incorporated with n and s fertilizer on the growth of rice fig. 3(b). effect of different combinations of organic and inorganic fertilizer on number of noneffective tillers plant-1 of brri dhan33 number of filled grain per plant significantly higher number of filled grain plant-1 (170) was recorded in t1 (100% inorganic fertilizer + 5 ton poultry manure/ha) and it was closely followed by t5 (169) and t2 (168). lowest number of filled grain plant-1(153) was found from the treatment using sole poultry manure (fig. 4.9). fig. 4. effect of different combinations of organic and inorganic fertilizer on number of filled grain plant-1 of brri dhan33 number of unfilled grain per plant the number of unfilled grain plant-1 differed significantly due to different combinations of organic and inorganic fertilizer (fig. 10). significantly lower number of unfilled grain plant-1 (39) was recorded in t1 and it was closely followed by t5 (41). highest number of unfilled grain plant-1 (47) was found from the treatment using sole poultry manure. 106 sarker et al. fig. 5. effect of different combinations of organic and inorganic fertilizer on number of unfilled grain plant-1 of brri dhan33 grain yield the higher grain yield (4.18 t ha-1) was recorded in t1 where lowest grain yield (3.67 t ha-1) was found from the treatment using sole poultry manure (figure 12). sarker et al. (2001) observed that application of nitrogen increased grain and straw yields significantly. fig. 6. effect of different combinations of organic and inorganic fertilizer on grain yield (t ha-1) of rice var. brri dhan33 chlorophyll content (mg g-1 fresh weight of leaf) the data on chlorophyll content (“a”, “b” and total) of rice at different growth stages as influenced by organic and inorganic fertilizers in table 1 a, b). the chlorophyll “a” content at different growth stages (45, 60 and 75 dat) differed significantly due to different treatments. significantly higher chlorophyll “a” (2.838, 1.592 and 0.61mg g-1 fresh weight of leaf respectively) was recorded in t1 while lowest chlorophyll “a” content from the treatment using sole poultry manure. significantly higher chlorophyll “b” (2.905, 2.358 and 0.351 mg g-1 fresh weight of leaf respectively) was recorded in t1 (100% inorganic fertilizer + 5 ton pm /ha). 107 effect of poultry manure incorporated with n and s fertilizer on the growth of rice table 1(a). effect of different combinations of organic and inorganic fertilizer on chlorophyll content of rice var. brri dhan33 treatments chlorophyll a (mg g-1 fresh weight of leaf) chlorophyll b(mg g-1 fresh weight of leaf) 45 dat 60 dat 75 dat 45 dat 60 dat 75 dat t1 2.838 a 1.592 a 0.61 a 2.905 a 2.358 a 0.351 a t2 2.532 b 1.428 b 0.466 bc 2.496 bc 1.808 c 0.328 a-c t3 2.458 bc 1.407 bc 0.452 bc 2.48 bc 1.504 d 0.246 a-c t4 2.406 b-d 1.383 bc 0.405 c 1.945 d 1.23 e 0.21 c t5 2.427 b-d 1.438 b 0.535ab 2.341 c 1.749 c 0.299 a-c t6 2.397 b-d 1.381 bc 0.534 ab 1.783 d 1.563 d 0.267 a-c t7 2.318 cd 1.374 bc 0.432 bc 1.571 e 1.474 d 0.266 a-c t8 2.339 cd 1.378 bc 0.401 c 2.435 bc 1.76 c 0.299 a-c t9 2.301 d 1.311 c 0.369 c 1.402 e 1.219 e 0.226 bc lsd0.05 0.1394 0.1061 0.1153 0.1781 0.1394 0.1104 cv % 3.01 2.54 1.987 3.25 1.69 5.13 table 1(b). effect of different combinations of organic and inorganic fertilizer on chlorophyll content (total) of rice var. brri dhan33 treatments total chlorophyll (mg g-1 fresh weight of leaf) 45 das 60 das 75 das t1 5.382 a 3.797 a 0.961 a t2 5.028 b 3.236 b 0.794 a-c t3 4.938 bc 2.911 cd 0.698 bc t4 4.351 d 2.613 e 0.615 bc t5 4.768 c 3.247 b 0.834 ab t6 4.18 d 2.944 cd 0.801 a-c t7 3.889 e 2.848 d 0.698 bc t8 4.774 c 3.138 bc 0.7 bc t9 3.703 f 2.53 e 0.595 c lsd (0.05 ) 0.17 0.23 0.19 cv (%) 3.57 2.91 3.39 n content in grain n content in grain (%) differed significantly among the different combinations of organic and inorganic fertilizer (figure 13). significantly higher n content in grain (1.28%) was recorded in t1 and lowest n content in grain (1.10%) from the treatment using poultry manure only. s content in grain (%) significantly higher s content (0.47%) was recorded in t5 and lowest s content (0.183%) was found from the treatment using poultry manure only (fig. 14). bari et al. (2013) was also found that nutrient content in grain increased while organic manure combined with inorganic fertilizers. 108 sarker et al. fig.7. effect of different combinations of organic and inorganic fertilizer on n content in grain (%) of brri dhan33 fig. 8. effect of different combinations of organic and inorganic fertilizer on s content in grain (%) of brri dhan33 n content in straw (%) n content in straw (%) differed significantly among the different combinations of organic and inorganic fertilizer (figure 4.15). significantly higher n content (0.351%) was recorded in t1 which was closely followed by t5 (0.334%). lowest n content (0.286%) was found from the treatment using poultry manure only. these results have the conformity with the results of bari et al. (2013). fig. 9. effect of different combinations of organic and inorganic fertilizer on n content in straw (%) of brri dhan33 109 effect of poultry manure incorporated with n and s fertilizer on the growth of rice p content in straw (%) p content in straw (%) differed insignificantly among the different combinations of organic and inorganic fertilizer (figure 16). though higher p content (0.213%) was recorded in t5 which was closely followed by t1 (0.195%). lowest p content (0.146%) was found from the treatment using poultry manure only. these results agree with the results of bari et al. (2013). fig. 10. effect of different combinations of organic and inorganic fertilizer on p content in straw (%) of brri dhan33 k content in straw (%) k content in straw (%) differed significantly among the different combinations of organic and inorganic fertilizer (figure 4.17 and appendix xi). significantly higher k content (1.8 %) was recorded in t2 which was closely followed by t5 (1.63%). better results were also given by t3 and t6 both of which gave 1.47% k in straw. lowest k content (1.15%) was found from the treatment using poultry manure only. these results have the conformity with the results of bari et al. (2013). fig. 11. effect of different combinations of organic and inorganic fertilizer on k content in straw (%) of brri dhan33 s content in straw (%) s content in straw (%) differed significantly among the different combinations of organic and inorganic fertilizer (fig. 18). significantly higher s content in straw (0.293%) was recorded in 110 sarker et al. t5 and lowest s content in straw (0.149 %) was found from the treatment using poultry manure only. these results have the conformity with the results of bari et al. (2013). fig. 12. effect of different combinations of organic and inorganic fertilizer on s content in straw (%) of brri dhan33 conclusion significant variation was found in growth and yield parameters as well as in chlorophyll content and nutrient content of aman rice due to the various combinations of organic and inorganic fertilizers. the treatment of 100% inorganic fertilizer + 5 ton poultry manure /ha could give the maximum growth, yield, chlorophyll and nutrient contents of rice var. brri dhan33. references amin, m., m.a. khan, e.a. khan, e. a. and m. ramzan. 2004. effect of increased plant density and fertilizer dose on the yield of rice variety ir-6. j. res. sci. 15(1), 09-16. bari, a.s.m.f., m a. khan, s. sultana, m. hasanuzzaman, n. sultana. 2013. effect of various inorganic fertilizer and manure with different water managements on yield and yield attributes of boro rice. j. expt. biosci. 4 (2): 1-6. brady, n. c. 1999. the nature and properties of soils. prentice hall of india pvt. ltd. delhi. channabasavanna, a. s. 2003. efficient utilization of poultry manure with inorganic fertilizer in wet land rice. j. maharashtra agric. univer. 27(3): 237-238. fao (food and agricultural organization). (1999). yearbook of production, fao statistics division. 605-607. hegde, d. m. and s. n. sudhakara babu. 2007. correcting sulphur deficiencies in soils and crops. indian j. fert. 3(1): 65-79. jackson, m l. 1973. soil chemical analysis. prentice-hall of india, pvt. ltd.. pp. 326-338. maynard, a.a. 1984. sustained vegetable production for three years using composted animal manures. j. am. soc. horti. sci. 94(3): 88-96. meelu, o. p. and yadvinder singh. 1991. integrated use of fertilizers and organic manure for higher returns. prog. fmg. punjab agric. univ. 27: 3-4. 111 effect of poultry manure incorporated with n and s fertilizer on the growth of rice nambiar, k. k. m. 1991. long-term fertility effects on wheat productivity. in wheat for the nontraditional warm areas, saunders d.a. ed., cimmyt. pp 516-521. ndaeyo, n.u., k.u. iboko, g. i. harry, and s. o. edem. (2008). growth and yield performances of some upland rice (oryza sativa l.) cultivars as influenced by varied rates of npk (15:15:15) fertilizer on an ultisol. j. trop. agric. food. env. ext. 7 (3): 249 – 255. russell df (1986) mstat-c pakage programme. crop and soil science department, michigan univ, usa. sadaphal, m. n., a. dayanand and t. singh. 1981. relative efficieny of different grades of urea and nitrogen rates for rice. indian j. agron. 26 (4): 428-431. saha, p.k., m.a. saleque, g.m. panaullah, and m.a. mazid miah. (2004). comparison of the fertilizer recommendation models for low land rice. bangladesh j. soil sci. 30 (1-2): 31-37. sarker, a. b. s., n. kojims and amano, y. 2001. effect of nitrogen rates on japonica and indica rice under irrigated ecosystem. bangladesh j. sci. and tenhol. 3(1): 49-58. sarvanan, a., v. velu, and k.m. ramanath, 1987. effect of combined application of bioorganic and chemical fertilizers on physical properties, nitrogen transformation and yield of rice in submerged soils. oryza: 1-6. singh, c. s. and u. n. singh. 2002. effect of nitrogen and sulphur nutrition on growth and yield of rice (oryza sativa l.) cultivars. res. crops. 3(3): 645-646. bangladesh agron. j. 2015, 18(1): 27-36 effect of irrigation and mulching on growth and yield of ginger m.a. islam1, m.a. rahim2 and t.m.t. iqbal3 1spices research center, bari, bogra; 2bau, department of horticulture, mymensingh 3department of horticulture, hstu, dinajpur key words: ginger, irrigation, mulching abstract a field experiment was conducted at the spices research center, bari, bogra, bangladesh during 2009-10 to determine the impact of irrigation and suitability of mulch materials on the growth and yield of ginger. the experiment was laid out in the randomized complete block design (rcbd) with three replications. the treatments comprising of two factors viz., two irrigation (i1: irrigation in dry period and i2: control i.e. no irrigation and three mulching material (m0: control (no mulch) m1: water hyacinth and m2: rice straw). treatment revealed that i1: (irrigation in dry period) showed that early emergence, highest plant height, number of leaves/plant, number of tillers/plant with maximum weight of primary and secondary rhizome, highest dry matter % and weight of old mother rhizome t ha-1. the highest yield of rhizome (21.19 t ha-1) was obtained from i1: (irrigation in dry period). among the mulch treatments, the highest rhizome yield (22.51 t ha-1) was obtained from m2 (ricer straw mulch). the combined effect of i1m2 (irrigation in dry period with rice straw mulch) produced the highest rhizome yield (25.07 t ha-1). introduction ginger (zingiber officinale rosc.) is an important spice crop in bangladesh. it is valued for its diversified uses in various drinks, medicines and culinary purposes (pruthi, 1998). beside the varietal factor, the yield of ginger can be increased with the adoption of improved agronomic practices, like irrigation and suitable mulch materials. mulch and irrigation are the two important aspects of ginger production. generally, farmers depend on unpredicted rainfall, which results in late planting. in the early season, soil remains dry, and therefore irrigation at the early stage is needed for ginger growth. the crop is affected by weed except when mulching and adequate weed control measures are taken during the early the stage of growth. generally, ginger is cultivated under the rainfed conditions in bangladesh. as irrigation facilities are inadequate and early monsoon rain is not certain, conservation of residual soil moisture by artificial means is be very useful for the plants in maximizing the growth and production of the crop. artificial mulches like water hyacinth and rice straw can be used to serve this purpose. mulch conserves soil moisture and protects sprouting of seed materials from excessive heat and desiccation (onwueme, 1978). application of mulch soon after planting is beneficial for the culture of some root and tuber crops (awal et al., 1978; jha et al., and 1986). mulched plot gives higher yield than non-mulched plot (nick et al., 1969; mannan and rashid, 1983). since soil moisture becomes a limiting factor for emergence and early growth of ginger, the use of mulch may be beneficial. irrigation and mulch play an important role to increase the yield potential of ginger. ginger is generally cultivated in kharif season in bangladesh. irrigation facilities are inadequate and the early monsoon rain is also uncertain. thus irrigation and 28 islam et al. mulching may be the most important factors of ginger production. so, this experiment was undertaken to investigate the effects of irrigation and mulching on the growth and yield of ginger. materials and methods the experiment was conducted at the research farm of the spices research centre, bari, bogra, during the period from april 2009 to january 2010. it has sub-tropical climate with an average annual rainfall of 237.13 mm. the soil was tista polal tract, having a ph value of 5.86.6. the experiment was laid out in a randomized complete block design (rcbd) with three replications. healthy ginger rhizome var. bari ada-1 was used for planting material. two irrigation levels viz., i1 (irrigation in dry period: 7days before planting and 60 days after planting) and i2 (no irrigation) were consisted as the first factor and three mulching materials viz., m0 (control), m1 (water hyacinth) and m2 (rice straw) were considered as the second factor. planting was done on the 1st april, 2009. the crop was fertilized with cowdung, urea, tsp, mp and gypsum at 5 ton, 304, 267, 233 and 111 kg ha-1, respectively. total cowdung was applied at the time of general land preparation and the entire quantity of tsp, gypsum and half of mp was applied during the final land preparation. half of the urea was applied 50 days after planting and the remaining mp and urea were applied in two equal splits at 80 and 110 days after planting. earthing up was done at 60, 90 and 110 days after planting. the data on different growth parameters were recorded from randomly of 10 selected plants of each plot 15 days interval at 50, 65, 80, 110, 125, 140 and 155 days after planting. yield and yield contributing characters were collected at harvesting time. the ist irrigation was applied 7 days before planting and the 2nd irrigation after 60 dap (days after planting). irrigation was done at the level of critical point indicated by moisture meter (delta t england). irrigation water applied twice 80 mm each time. irrigation water was applied twice at 7 days before planting and at 60 days after planting. the discharge of water through hose pipe (diameter 2.5 cm) was calibrated before application. the discharge of water through this pipe was 20 mm pipe per minute. the mulch materials were covering with the 4 cm thickness. water hyacinth and rice straw mulch were placed before the rhizomes started to emerge. a second mulch was added at 60 days after planting as the first one was washed away by rain, wind and irrigation water. rice straw and water hyacinth were applied at 2.0 and 2.5 kg/m2; respectively. the soil samples were taken from each plot at 0-10 cm depth before each irrigation. the samples were weighed and oven dried at 1000 c for 24 hours. the collected data were analyzed statistically and adjusted with least significance (lsd) at 5% level of probability. results and discussion soil moisture content soil moisture at the field capacity of the experimental plot was 25.4%. at the beginning, application of mulch in non-irrigated or irrigated plot conserved more moisture compared to non-mulch + no-irrigation plot. at this time, rice straw mulch + no-irrigation conserved about 1.8% more moisture than water hyacinth + no-irrigation treatment. similarly rice straw mulch + irrigation conserved about 1.14% more moisture than water hyacinth + irrigation treatment. irrigation applied after two months of planting showed that moisture content in rice straw mulch + irrigation conserved more moisture compared to water hyacinth + irrigation and nomulch + irrigation treatments (table 1). at this time, rice straw mulch + irrigation conserved 29 effect of irrigation and mulching on growth and yield of ginger about 1.01% more moisture than water hyacinth + irrigation treatment. the highest soil moisture was found in irrigation + rice straw mulch (19.35% in before planting and 8.65% in two months after planting) while the lowest moisture control treatment (17.0 %) before planting and 6.5% in two months after planting) (table 1). the rice straw mulch possibly conserved more soil moisture and suppressed weeds (table 1), which helped plant growth and deposition of more food materials. similar result was also reported by ghosh et al. (2007) who observed the maximum yield per plant from the plants under the paddy straw mulch. the influence of mulching treatment was found significant on the rhizome yield. table 1. residual soil moisture contents of the experimental plots at 10 cm depth at the beginning and two months after planting the crop treatment combination moisture content at the beginning (%) moisture content after 2 month of planting (%) moisture at field capacity (%) control + no irrigation 17.00 6.50 25.4 water hyacinth + no irrigation 17.80 7.10 rice straw + no irrigation 18.00 8.13 control + irrigation in dry period 17.22 6.85 water hyacinth + irrigation in dry period 18.21 7.64 rice straw + irrigation in dry period 19.35 8.65 plant height was significantly influenced by irrigation. the highest plant (71.66 cm) was obtained from the treatment i1 (irrigation in dry period) and the lowest (60.45 cm) in i2 (control) treatment at the 125 dap (fig. 1). the better result in i1 may be due to conserved soil moisture that favored rapid plant growth. this finding agrees with pawar, 1990; and singh et al., 2000. mulch had significant influence on plant height. the tallest plant (74.29 cm) was found in the treatment m2 (rice straw mulch) while the lowest (57.30 cm) in m0 (control) treatment at 125 dap (fig.2). 20 30 40 50 60 70 80 50 65 80 95 110 125 140 155 days after planting p la n t h e ig h t (c m ) i1( irrigation in dry period) i2( no irrigation) 20 30 40 50 60 70 80 50 65 80 95 110 125 140 155 days after planting p la n t h e ig h t (c m ) m0(no mulch) m1(water hyacinth) m2(rice straw) fig. 1. main effects of irrigation on the plant height of ginger. vertical bars represent lsd at 5% level of probability fig. 2. main effects of mulching on the plant height of ginger. vertical bars represent lsd at 5% level of probability after 125 dap, plant height decreased gradually due to senescence of leaves. it might be due to mulching which had reduced the evaporation of soil moisture, weed growth and conserved moisture from rainfall during the early stage of plant growth. similar result was also reported by mohanthy et al. (1991), chandra et al. (2001) and ghosh et al. (2007). 30 islam et al. the combined effect of irrigation and mulching on plant height was significant from 50 to 155 dap. the tallest plant (79.76 cm) was recorded from i1m2 (irrigation in dry period with rice straw mulch) and the shortest plant (50.87 cm) from i2m0 (control) at 125 dap (table 4). possible due to irrigation with rice straw mulching reduced soil temperature, conserved soil moisture, minimize the evaporation loss and enhances root growth and water use efficiency. so, plant was vigorous and rapid growth. this finding agreed with the finding of zaman et al. (2002) and mishra and mishra (1982). the numbers of leaves per plant were counted at different growth stages and interval of 15 days at 50, 65, 80, 95, 110, 125, 140 and 155 dap. a significant variation was observed for numbers of leaves per plant at those stages and interval. the highest number of leaves (106.28) was recorded from i1 (irrigation in dry period) and the lowest (88.77) in the i2 (control) treatment at 125 dap (fig. 3). irrigation increased soil moisture content by plants resulting enhanced growth of plants. this finding agrees with pawar (1990) and singh et al. (2000). in case of mulch, the maximum number of leaves (129.28) was recorded from m2 (rice straw) while the minimum (70.55) was recorded from m0 (control) treatment at 125 dap (fig. 4). 0 20 40 60 80 100 120 50 65 80 95 110 125 140 155 days after planting n u m b e r o f le a v e s p e r p la n t i1( irrigation in dry period) i2( no irrigation) 0 20 40 60 80 100 120 140 50 65 80 95 110 125 140 155 days after planting n u m b e r o f le a v e s p e r p la n t m0(no mulch) m1(water hyacinth) m2(rice straw) fig. 3. main effects of irrigation on the number of leaves per plant of ginger. vertical bars represent lsd at 5% level of probability fig.4. main effects of mulching on the number of leaves per plant of ginger. vertical bars represent lsd at 5% level of probability almost similar trend regarding number of leaves per plant was obtained by ghosh et al. (2007). in case of combined effect the highest number of leaves (141.80) was counted in the i1m2 (irrigation in dry period with rice straw mulch) while the lowest (62.10) was obtained from i2m0 (control) treatment combinations at 125 dap (table 4). it might be due to that irrigation supplied water and mulch conserved moisture in the soil to some extend which was used by the plants to promote more number of leaves per plants ghosh (1996) obtained higher number of leaves per plant from rice straw mulch. the number of tillers per plant was counted at different growth stage at an interval of 15 days viz. 50, 65, 80, 95, 110, 125, 140 and 155 dap. the highest number of tillers per plant (12.25) was obtained from i1 treatment while the lowest number of tillers per plant (9.96) was obtained from i2 (control) treatment at 125 dap (fig. 5). it might be due to soil moisture that created favorable environment to absorb nutrients resulting more number of tillers per plant. this finding agrees with those of pawar (1990) and singh et al. (2000). in case of mulch, the maximum number of tillers per plant (13.91) was found in m2 (rice straw mulch) and the lowest 31 effect of irrigation and mulching on growth and yield of ginger (9.23) from m0 (control) treatment at 125 dap (fig. 6). possibly mulch conserved t soil moisture in the soil to some extent which helped to produce more number of tillers per plant. ghosh et al. (2007) and ghosh (1996) reported that application of straw mulch produced maximum number of tillers per plant. 0 5 10 15 20 50 65 80 95 110 125 140 155 days after planting n u m b e r o f ti ll e rs p e r p la n t i1( irrigation in dry period) i2( no irrigation) 0 2 4 6 8 10 12 14 16 50 65 80 95 110 125 140 155 days after planting n u m b e r o f ti ll e rs p e r p la n t m0(no mulch) m1(water hyacinth) m2(rice straw) fig.5. main effects of irrigation on the number of tillers per plant of ginger. vertical bars represent lsd at 5% level of probability fig.6. main effects of mulch on the number of tillers per plant of ginger. vertical bars represent lsd at 5% level of probability irrigation treatments had a significant effect on 80% emergence of seed rhizome (table 2). the i1 treatment (irrigation in dry period) required the minimum time (27 days) to complete 80% emergence while it was maximum (45.33 days) in i2 (control) treatment. similar result was also reported by pawar, 1990 and singh et al., 2000. the weight of primary and secondary rhizome varied significantly due to irrigation, mulching and their combination. different irrigation treatments had significant effect on the weight of primary and secondary rhizome per plant. the i1 (irrigation in dry period) treatment showed the highest yield/plant (268.07 g and 60.80 g) of primary and secondary rhizome respectively. the lowest yield (215.81 g and 51.30 g) primary and secondary rhizome/plant was recorded from i2 (control) treatment respectively (table 2). this might be due to suitable soil moisture which enhanced rapid growth using the initial reserve food material. different mulching treatments had significant effect on the weight of primary and secondary rhizome per plant. the maximum weight of primary rhizome (281.85 g)/plant was found from m2 (rice straw mulch) and the lowest (197.17 g)/plant was obtained from m0 (control) treatment (table 3). similar trend of result was obtained in case of secondary rhizome per plant where the maximum weight of secondary rhizome per plant was found from m2 (68.44 g)/plant and the lowest from m0 (45.89 g) /plant (table 3). the maximum weight of primary and secondary rhizome per plant in m2 (rice straw mulch) might be due to more soil moisture conserved by this treatment. the weight of primary and secondary rhizome significantly increased due to combined effect of mulching and irrigation treatment. the maximum weight of primary rhizome (308.94 g)/plant was recorded from i1m2 (irrigation in dry period with rice straw mulch) while the lowest (169.33 g) /plant was obtained from i2m0 (control) treatment combination (table 4). the maximum weight of secondary rhizome (75.0g)/plant was recorded from i1m2 (irrigation in dry period + rice straw mulch) while the lowest (45.00 g) /plant was obtained from i2m0 (control) treatment combination (table 4). irrigation + rice straw mulch applied plot showed vigorous plants compared to water hyacinth + irrigation and control treatment, which helped in greater deposition accumulation of assimilates 32 islam et al. to the primary and secondary rhizomes. as a consequence it produced maximum weight of primary and secondary rhizome per plant. the dry matter of rhizome varied significantly due to irrigation, mulching and their combined effects. the maximum dry matter of rhizome 23.38% and 23.82% was found from i1 (irrigation in dry period) and m2 (rice straw mulch), respectively and the minimum 21.50% and 21.00% was from i2 (control) and m0 (control), respectively (table 2 & 3). in respect of combined effect of irrigation and mulching, it was observed that i1m2 (irrigation in dry period with rice straw mulch) produced the highest (24.63%) dry matter of rhizome. it might be due to higher vegetative growth and more accumulation of photosynthates. i2m0 (control) gave the lowest (20%) dry matter of rhizome (table 4). weight of old mother rhizome was significantly influenced by irrigation, mulching and their combination. the maximum (2.55 t ha-1 and 2.63 t ha-1) old mother rhizome was recorded from i1 (irrigation in dry period) and m2 (rice straw mulch) treatment, respectively. this finding is similar to ghosh (1996) that reported the highest weight of old mother rhizomes was obtained from the rice straw mulch treatment. it might be happened due to the fact that the i1 treatment and m2 rice straw mulch conserved more soil moisture which caused more weight of old mother rhizomes. the minimum weight was (1.88 t ha-1 and 1.80 t ha-1) from i2 (control) and m0 (control), treatment respectively (table 2 & 3). the combined effect of irrigation and mulching significantly influenced the weight of old mother rhizomes. the highest weight (3.0 t ha-1) was obtained from the i1m2 and the lowest (1.5 t ha-1) was obtained from the i2m0 (control) treatment combination (table 4). significant difference in yield (t ha-1) was observed by the effect of irrigation, mulching and their combination. the maximum yield of 198.74 g/plant, 12.72 kg /plot and 21.19 t ha-1 were obtained from i1 (irrigation in dry period) treatment respectively and the lowest 158.15 g/plant 10.12 kg/plot and 16.87 t ha-1 recorded from i2 (control) treatment (table 2). the irrigation treatment (i1) possibly produced more number of leaves per plant, which helped in higher photosynthates and ultimately resulted accumulation of more food material. this finding agrees with the findings of pawar (1990) and singh et al. (2000) who stated that the adequate irrigation increased rhizome yield per hectare. beside this, highest yield (211.05 g/plant) was found from m2 treatment (rice straw mulch) and the lowest (153.61 g/plant) from m0 (control) treatment (table 3). the rice straw mulch possibly conserved more soil moisture and suppressed weeds (table 1), which helped plant growth and deposition of more food materials. similar result was also reported by ghosh et al. (2007) who observed the maximum yield per plant from the plants under the paddy straw mulch. the influence of mulching treatment was found significant on the rhizome yield. the height rhizome yield (13.50 kg/plot) was recorded from m2 (rice straw mulch) while the lowest yield (9.83 kg/plot) was found from m0 (control) treatment. similarly different mulching treatments showed significant effect on the rhizome yield t ha-1 of ginger. the maximum rhizome yield (22.51 t ha-1) was found from m2 treatment and the lowest (16.38 t ha-1) from m0 treatment (table 3). it might be due to rice straw mulch conserved more soil moisture (table 1) and suppressed weeds, which helped produce more number of leaves per plant, enhanced plant growth, deposited of more food material and finally gave more yield. similar results were also found by mishra and mishra (1982), ghosh (1996), and ghosh et al., 2007). the combined effect irrigation and mulching was found significant on the rhizome yield per plot and yield per hectare. the maximum rhizome yield (15.04 kg/plot) was recorded from i1m2 and the minimum (8.86 kg/plot) was found from i2m0 treatment (table 4). similarly the maximum yield of rhizome (25.07 t ha-1) was obtained from i1m2 while the lowest (14.76 t ha-1) was 33 effect of irrigation and mulching on growth and yield of ginger found from i2m0 treatment combination (table 4). the treatment i1m2 was observed better as irrigation and straw mulch conserved more soil moisture and suppressed weed growth. so, crop growth was better with the maximum number of leaves per plant, which helped in photosynthesis and ultimately resulted maximum rhizome yield per hectare. this finding was in agreement with those of pawar (1990) and singh et al. (2000). they reported that irrigation with mulching produced the highest yield of rhizomes per hectare. table 2. effect of irrigation on the growth and yield of ginger treatment emergence (%) at dap wt. of primary rhizomes/plant (g) wt. of secondary rhizomes/ plant (g) dry matter (%) weight of old mother rhizomes (t ha-1) rhizome yield (t ha-1) 20 40 60 80 i1 18.00 21.33 23.33 27.00 268.07 60.80 23.38 2.55 21.19 i2 24.33 30.00 36.67 45.33 215.81 51.30 21.50 1.88 16.87 lsd (0.05) 3.31 3.74 4.59 3.81 5.08 5.95 0.57 0.39 3.87 cv (%) 10.53 9.83 10.31 7.10 1.42 7.17 1.73 11.89 13.75 i1: irrigation in dry period, i2: no irrigation, dap: days after planting table 3. effect of mulching on the growth and yield of ginger treatment emergence (%) at dap wt. of primary rhizomes/plant (g) wt. of secondary rhizomes/ plant (g) dry matter (%) weight of old mother rhizomes (t ha-1) rhizome yield (t ha-1) 20 40 60 80 m0 25.5 31.00 35.00 39.50 197.17 45.89 21.00 1.80 16.38 m1 20.5 25.00 29.50 36.00 246.80 53.82 22.50 2.23 18.20 m2 17.5 21.00 25.5 33.00 281.85 68.44 23.82 2.63 22.51 lsd (0.05) 2.87 3.25 3.98 3.31 4.41 5.17 0. 50 0.34 3.37 cv (%) 10.53 9.83 10.31 7.10 1.42 7.17 1.73 11.89 13.75 m0: no mulch, m1: water hyacinth, m2: rice straw, dap: days after planting on the other hand mulch had significant effect on 80% emergence. it was observed that the plants under m2 (rice straw mulch) took the minimum (33.0 days) to complete 80% emergence while it was maximum (39.5 days) in case of m0 (control) treatment (table 3). mulch conserved more soil moisture which enhanced quicker emergence than control treatment. this finding agrees with the finding of kumar et al. (1973) who observed that mulching enhanced early emergence. different mulching treatments had significant effect on the weight of primary and secondary rhizome per plant. the maximum weight of primary rhizome (281.85 g)/plant was found from m2 (rice straw mulch) and the lowest (197.17 g)/plant was obtained from m0 (control) treatment (table 3). similar trend of result was obtained in case of secondary rhizome per plant where the maximum weight of secondary rhizome per plant was found from m2 (68.44 g)/plant and the lowest from m0 (45.89 g) /plant (table 3). beside this, highest yield (211.05 g/plant) was found from m2 treatment (rice straw mulch) and the lowest (153.61 g/plant) from m0 (control) treatment (table 3). the height rhizome yield (13.50 kg/plot) was recorded from m2 (rice straw mulch) while the lowest yield (9.83 kg/plot) was found from m0 (control) treatment. similarly different mulching treatments showed significant effect on the 34 islam et al. rhizome yield t ha-1 of ginger. the maximum rhizome yield (22.51 t ha-1) was found from m2 treatment and the lowest (16.38 t ha-1) from m0 treatment (table 3). it might be due to rice straw mulch conserved more soil moisture and suppressed weeds, which helped produce more number of leaves per plant, enhanced plant growth, deposited of more food material and finally gave more yield. similar results were also found by mishra and mishra (1982), ghosh (1996), and ghosh et al., 2007). table 4. combined effect of irrigation and mulching on the growth and yield of ginger treatment plant height (cm) at different days after planting no. of leaves/plant at different days after planting 50 65 80 95 110 125 140 155 50 65 80 95 110 125 140 155 i1m0 37.93 45.40 50.33 53.00 60.93 63.73 51.80 45.93 24.77 34.80 41.63 59.53 68.53 79.00 62.80 43.17 i1m1 48.62 53.81 59.65 63.43 68.27 71.49 61.73 51.87 36.22 42.74 63.87 75.23 83.92 98.05 74.62 58.53 i1m2 53.77 63.09 67.77 71.87 76.07 79.76 70.47 61.17 49.49 62.55 71.17 98.68 122.95 141.80 110.14 92.00 i2m0 30.66 37.25 41.95 44.93 46.30 50.87 43.30 30.57 20.53 30.40 37.27 49.40 57,33 62.10 54.88 35.80 i2m1 40.60 46.87 49.81 51.43 56.44 61.67 52.06 44.42 33.60 41.70 56.17 63.00 78.07 87.43 72.33 60.38 i2m2 46.72 51.89 55.30 62.14 65.72 68.82 59.28 54.38 37.02 49.89 63.60 78.04 91.73 116.76 85.27 77.33 cv (%) 8.89 7.78 7.11 7.57 6.42 6.35 6.86 8.91 6.10 5.18 4.32 6.53 5.34 3.76 4.72 5.87 table 4. (contd.) treatment no. of tillers/plant at different days after planting emergence (%) wt. of primary rhizomes/ plant (g) wt. of secondary rhizomes/ plant (g) dry matter (%) weight of old mother rhizomes (t ha-1) rhizome yield (t ha1) 50 65 80 95 110 125 140 155 20 40 60 80 i1m0 3.53 4.14 5.02 6.47 7.73 10.13 7.43 5.73 21.0 24.0 26.0 30.0 225.00 46.78 22.00 2.10 18.00 i1m1 4.91 6.18 6.37 8.57 9.86 11.84 8.28 7.01 18.0 22.0 24.0 27.0 270.26 60.62 23.5 2.56 20.51 i1m2 7.06 8.60 10.88 12.10 14.17 15.97 11.98 9.59 15.0 18.0 20.0 24.0 308.94 75.00 24.63 3.00 25.07 i2m0 2.83 3.67 4.68 5.37 6.47 8.33 6.23 4.30 30.0 38.0 44.0 49.0 169.33 45.00 20.0 1.50 14.76 i2m1 4.43 4.50 5.33 6.40 8.47 9.69 7.53 5.19 23.0 28.0 35.0 45.0 223.34 47.02 21.50 1.90 15.89 i2m2 5.37 6.37 7.51 8.30 10.50 11.85 9.17 6.89 20.0 24.0 31.0 42.0 254.75 61.87 23.0 2.25 19.95 lsd (0.05) 0.87 0.87 1.23 1.27 1.38 0.89 2.34 1.64 4.06 4.59 5.63 4.67 6.23 7.31 0.71 0.48 4.76 cv (%) 10.21 8.61 10.23 8.88 7.97 4.31 15.22 13.98 10.53 9.83 10.31 7.10 1.42 7.17 1.73 11.89 13.75 i1: irrigation in dry period, i2: no irrigation, m0: no mulch, m1: water hyacinth mulch, m2: rice straw mulch, dap: days after planting in case of combined effect the, maximum (49.0 days) were recorded in i2m0 (control) treatment while the minimum (24.0 days) were required in i1m2 (irrigation in dry period with rice straw mulch) treatment combination (table 4). it might be due to the fact that irrigation and mulching conserved soil moisture, reduced soil temperature, minimized the evaporation loss, and enhanced root growth. this finding agrees with those of chowdhury and prihar (1974), pawar (1990) and ghosh et al. (2007). the combined effect of irrigation and mulching on plant height was significant from 50 to 155 dap. the tallest plant (79.76 cm) was recorded from i1m2 (irrigation in dry period with rice straw mulch) and the shortest plant (50.87 cm) from i2m0 (control) at 125 dap (table 4). it might be possible due to irrigation with rice straw mulching reduced soil temperature, conserved soil moisture, minimize the evaporation loss and enhances root growth and water use efficiency. so, plant was vigorous and rapid growth. this finding agreed with the finding of zaman et al. (2002) and mishra and mishra (1982). almost similar trend regarding number of leaves per plant was obtained by ghosh et al. (2007). in case of combined effect the highest number of leaves (141.80) was counted in the i1m2 (irrigation in 35 effect of irrigation and mulching on growth and yield of ginger dry period with rice straw mulch) while the lowest (62.10) was obtained from i2m0 (control) treatment combinations at 125 dap (table 4). it might be due to that irrigation supplied water and mulch conserved moisture in the soil to some extend which was used by the plants to promote more number of leaves per plants ghosh (1996) obtained higher number of leaves per plant from rice straw mulch. the maximum weight of primary and secondary rhizome per plant in m2 (rice straw mulch) might be due to more soil moisture conserved by this treatment. the weight of primary and secondary rhizome significantly increased due to combined effect of mulching and irrigation treatment. the maximum weight of primary rhizome (308.94 g)/plant was recorded from i1m2 (irrigation in dry period with rice straw mulch) while the lowest (169.33 g) /plant was obtained from i2m0 (control) treatment combination (table 4). the maximum weight of secondary rhizome (75.0g)/plant was recorded from i1m2 (irrigation in dry period + rice straw mulch) while the lowest (45.00 g)/plant was obtained from i2m0 (control) treatment combination (table 4). irrigation + rice straw mulch applied plot showed vigorous plants compared to water hyacinth + irrigation and control treatment, which helped in greater deposition accumulation of assimilates to the primary and secondary rhizomes. as a consequence it produced maximum weight of primary and secondary rhizome per plant. in respect of combined effect of irrigation and mulching, it was observed that i1m2 (irrigation in dry period with rice straw mulch) produced the highest (24.63%) dry matter of rhizome. it might be due to higher vegetative growth and more accumulation of photosynthates. i2m0 (control) gave the lowest (20%) dry matter of rhizome (table 4). the combined effect of irrigation and mulching significantly influenced the weight of old mother rhizomes. the highest weight (3.0 t ha-1) was obtained from the i1m2 and the lowest (1.5 t ha-1) was obtained from the i2m0 (control) treatment combination (table 4). the combined effect irrigation and mulching was found significant on the rhizome yield per hectare. the maximum rhizome yield (15.04 kg/plot) was recorded from i1m2 and the minimum (8.86 kg/plot) was found from i2m0 treatment (table 4). similarly the maximum yield of rhizome (25.07 t ha-1) was obtained from i1m2 while the lowest (14.76 t ha-1) was found from i2m0 treatment combination (table 4). the treatment i1m2 was observed better as irrigation and straw mulch conserved more soil moisture and suppressed weed growth. so, crop growth was better with the maximum number of leaves per plant, which helped in photosynthesis and ultimately resulted in maximum rhizome yield per hectare. this finding was in agreement with those of pawar (1990) and singh et al. (2000). they reported that irrigation with mulching produced the highest yield of rhizomes per hectare. the combined effect of irrigation and mulching was significant to influence the number of tillers per plant. the highest number of tillers per plant (15.97) was counted from i1m2 and the lowest (8.33) from i2m0 (control) treatment combination at 125 dap (table 4). this might be due to i1m2 irrigation and mulch reduced soil temperature fluctuation, minimized evaporation loss, conserved soil moisture, enhanced root growth and produced more number of tillers per plant. almost similar trend in number of tillers per plant was obtained by ghosh (1996). ghosh (2007) reported that plants with rice straw mulch produced maximum number of tillers per plant followed by water hyacinth. conclusion the study concluded that the rhizome yield of ginger was significantly affected by the irrigation, mulching and their combined effects. the growth and yield attributes of ginger rhizome were increased when irrigation as applied irrigation in dry period (7 days before planting and 60 days after planting). mulching also influenced the growth and yield of ginger rhizome. the rice straw mulch gave the highest yield of ginger rhizome. however, irrigation in dry period with rice 36 islam et al. straw mulch resulted in the highest rhizome yield per unit area. further investigation is needed in suggested for different agro-ecological region of bangladesh in order to confirm the present findings. references awal, m. a., m. m. hossain and m. m. rashid. 1978. the effect of methode of seed bed preparation, mulching and intertillage on the growth and yield of mukhi kachu (colocasia esculenta var. globulifera). bangladesh hort. 6(1-2): 9-13. chandra, r., g. sheo, r. chandra and s. goving. 2001. effect of mulching on yield of ginger. j. spices aromatic crops 10(1): 13-16. chowdhury, m. r and s. s. prihar. 1974. root development and growth response of corn following mulching. cultivation and inter row compaction. agron. j. 66: 350-355. ghosh, d. k., j. k. hoer, a. bandopadhyay, n. chattopadhyay and s. s. roy. 2007. effect of spacing and rhizome size on yield of turmeric grown as intercrope in coconut plantation. seminar heald on bidhan chandra krishi, viswavidyalaya mohanpur 741252, nadia, west bengal, india. ghosh. k. s. 1996. effect of spacing and mulching on the growth and yield of ginger (zingiber officinale rosc.). m. s. thesis. department of horticulture, bau, mymensingh, pp. 38. jha, r.c., k.r. maurya and r.d. pandey. 1986. influence of mulching on the yield of ginger in bihar. indian cocoa arecanut spices j. 9(4):87-90. kumar, c. r. m., r. c. mandal and k. d. singh. 1973. effect of mulching and plant density on growth, yield and quality of amorphophallus. indian j. agron., 18(1): 62-66. mannan, m.a. and m. m. rashid. 1983. effect of spacing and mulching on the yield and profitability of pancha mukhi kachu. bangladesh j. agril. res. 8(2): 70-73. mishra, s. and s. s. mishra. 1982. effect of mulching and weedicides on growth and fresh rhizome yield of ginger. annual conference of indian society of weed science, 1982 (undated) 33. mohanthy, d. c., y. n. serma and b. s. panda. 1991. effect of mulch materials and intercrops on the yield of turmeric under rain fed conditions. indian cocoa arecanut spices j. 15(1): 811. nick, j., j. e. moody and j. h. lillard. 1969. effect of number of tillage and mulch on soil water and plant growth. agron. j. 61(15): 719-721. onwueme, i. c. 1978. the tropical tuber crops. john wiley and sons, chichester, pp. 199-227. pawar, h. k. 1990. use of plastic as a mulch in scheduling of irrigation to ginger in semiarid climate. proceedings of the 11th international congress on the use of plastics in agriculture, new delhi, india, 26th february2nd march. e.99e.109. pruthi, j. s. 1998. spices and condiments. nation book trust, new delhi, pp. 147-152. singh, j. p., prasad, u. k. and h. singh. 2000. effect of irrigation and drainage requirement on water-use efficiency and yield pure (crops turmeric) and maize based inter crops. indian j. agril. sci. 70(2): 65-68. zaman, m. m., a. s. m. h. masum, n. u. ahmed, m. a. salam and m. h. rahman. 2002. effect of tillage and mulch on the growth and yield of ginger in the hilly area. online j. biol. sci. 2(2): 121-123. on-farm evalution of production potential and economics of mustard-rice based improved cropping system bangladesh agron. j. 2016, 19(2): 87-94 on-farm assessment of system productivity of wheatjute-t. aman rice cropping pattern in sylhet region m.i. nazrul ofrd, bangladesh agricultural research institute (bari), bangladesh. *corresponding author: mi_nazrul@yahoo.com key words: agronomic performance, land use efficiency, production potential, sustainable yield index abstract the study was conducted to determine the yield and economic performance of two cropping patterns viz. ip: improved pattern (wheat jute t. aman) + improved management practice and fp: farmer’s pattern (fallow t. aus t. aman) + management practice. the experiment was laid out in a randomized complete block design with six dispersed replications at farmer’s field in sylhet region during two consecutive years of 2013-14 and 2014-15. two years means data showed that the pattern with improved management practices provided 31% higher yield of t. aman rice and also contributed more rice equivalent yield compared to farmers practice. sustainable yield index, production efficiency, and land use efficiency were the maximum with wheatjutet. aman cropping system. similarly, highest mean gross margin and benefit cost ratio were attained in improved pattern. it was concluded that farmers of sylhet region might follow wheat (var. bari gom-26) jute (var. cvl-1) t. aman (var. binadhan-7) cropping system in medium high land for higher productivity and profitability. introduction fallow t. aus t. aman rice and boro fallow t. aman rice etc. are the important and popular cropping pattern in hobiganj of sylhet region. farmers mostly cultivate rice under rainfed condition and thus , transplanting of t. aus depends on the onset of rainfall. the delayed transplantation of t. aus causes late cultivation and harvesting of t. aman rice. due to late harvesting of t. aman, all rabi crops are not possible to be grown. the soils under cropping pattern of these areas are generally heavy clay loams to clays and the top soil quickly becomes dry and hard after the harvest of t. aman crop. more than 40% land remains fallow for a long time (december-may) after the harvest of t. aman due to moisture stress (up to kharif-i) in eastern surma-kushiyara floodplain (aez-20) and northern and eastern piedmont plain (aez-22). farmers of the mentioned areas wait for cultivating t. aus rice following the existing cropping pattern (fallow t. aus t. aman) under rainfed condition. but the weather data of study areas revealed that rainfall starts here in february and prevails up to november in each year that offers an excellent opportunity for the production of short duration crop. bari has been developed more than 27 wheat varieties with high yield potential and good quality. among the bari released wheat varieties, bari gom-24, bari gom-25, bari gom-26, bari gom-27 and bari gom-28 have been popularized in different areas of the country and farmers are adopting the varieties rapidly. in order to increase production, wheat can be cultivated before jute under wheat jute t. aman rice based cropping pattern instead of existing fallow t. aus t. aman cropping pattern in aez-20 of bangladesh. a number of reports on different cropping pattern are available in bangladesh and india that indicate that an additional crop 88 m.i. nazrul could be introduced without much changes or replacing the existing ones for considerable increases of productivity as well as profitability of the farmers (wahhab and azad, 1981; azad et al. 1982; malavia et al. 1986; soni and kaur, 1984; khan et al., 2005 and nazrul, et al. 2013). but, little efforts have been made for on-farm evaluation of the improved technologies of wheat-jute-t. aman rice cropping pattern in sylhet area. the present study was therefore, initiated to find out the agroeconomic feasibility of an improved package of technologies over the farmers existing practices. materials and methods on-farm trials were carried with out in farmer’s field under eastern surma kushiyara floodplain (aez-20) which is located in between 23°58' and 24°16' north latitudes and in between 91°16' and 91°25' east longitudes of bangladesh, during two consecutive years 2013-14 and 2014-15. this trial was conducted to with two cropping patterns viz. ip: improved pattern (wheat jute t. aman) and fp: farmer’s pattern (fallow t. aus t. aman) through inclusion of modern high yielding varieties of jute, t. aman rice as well as wheat and improved management practices for crop production. annual monthly total rainfall 3821 mm was during the period 2014-15. average maximum and minimum temperature was 31.34 and was 14.720c, respectively (fig.1). the soil was clay loam with low organic matter content (1.30%) and soil ph was ranged 5.3-6.2 acidic in nature. the status of n, p, k, s, b and zn was very low, low, low, very low and medium, respectively. the experimental design was a randomized complete block with six dispersed replications with plot size of 500 m2.one plot was under the improved pattern and the other farmer’s pattern. in the improved pattern, wheat var. bari gom-26 was introduced against fallow period. the var. cvl-1 of jute and binadhan-7 of t. aman rice was introduced instead of br26 and brri dhan33, respectively. the agronomic practices and cultural operation for crop production under improved and farmer’s practices are presented in table 1. all field operation and management practices of both farmer’s and improved pattern were closely monitored and the data were recorded for agro-economic performance. the yield differences between the practices were statistically analyzed by‘t’ test. agronomic performance viz. land use efficiency, production efficiency, rice equivalent yield and sustainable yield index of cropping patterns were calculated by the following formula: land use efficiency: land use efficiency is worked out by taking total duration of individual crop in a sequence divided by 365 days (tomer and tiwari, 1990). it is calculated by following formula. land use efficiency = d1 + d2 + d3 × 100 365 where d 1 , d 2 and d 3 the duration of 1 st , 2 nd and 3 rd crops of the pattern. production efficiency: production efficiency values in terms of kg.ha-1day-1 were calculated by total production in a cropping sequence divided by total duration of crops in that sequence (tomer and tiwari. 1990). production efficiency = y1 + y2 + y3 d1 + d2 + d3 89 on-farm assessment of system productivity of wheat-jute-t. aman rice cropping pattern in sylhet region where, y1= yield of 1 st crop and d1= duration of 1 st crop of the pattern y2= yield of 2 nd crop and d2= duration of 2 nd crop of the pattern y3= yield of 3 rd crop and d3= duration of 3 rd crop of the pattern sustainable yield index: sustainable yield index (syi) was worked out by the following formula suggest by krishna and reddy (1997). sustainable yield index (syi) = ymeansd × 100 ymax where, ymean: estimated mean yield of a practice over years; sd: estimated standard deviation; ymax: observed maximum yield in the experiment over the years. rice equivalent yield (rey): for comparison between crop sequences, the yield of all crops was converted into rice equivalent on the basis of prevailing market price of individual crop (verma and modgal, 1983; bandyopadhyay, 1984). the economic indices like gross and net returns and benefit cost ration were also calculated on the basis of prevailing market price of the produces. rice equivalent yield (t ha-1) = yield of individual crop × market price of that crop market price of rice for economic evaluation of two different cropping sequences averaged data of two crop cycles were used. the gross cost of cultivation of different crops was calculated on the basis of different operations performed and materials used for raising the crops. gross margin, gross return and total cost of cultivation of the component crops were calculated as well as benefit cost ratio (bcr) as per following formula. benefit cost ratio (bcr) = gross return (tk. ha-1) total variable cost of cultivation (tk. ha-1) fig. 1. month wise total rainfall (mm) and temperature during study period 2013-15 in srimangal, moulvibazar. results and discussion 90 m.i. nazrul grain/fiber yield of the cropping patterns improved pattern required 288-309 days against 181-190 days due to inclusion of jute instead of t. aus rice in the pattern, but can be easily fitted before t. aman rice (table 1). yield of t. aman rice in the improved pattern was higher due to change of variety with improved production technologies (table 2). similar results were also obtained by nazrul et al. (2013), khan et al. (2006), khan et al. (2005) and hossain and wahhab (1992). in both years, farmers’ pattern gave lower grain yield of rice due to imbalance use of fertilizers and more plant population. the rice variety, binadhan-7 in improved pattern performed better than brri dhan33 in farmers’ practices due to use of balance fertilizer and modern technology. by-product yield of the cropping patterns the improved cropping pattern produced higher amount of total by-product yield (12.95 t/ha) than the by-product yield of the crops of the farmers’ pattern (9.07 t ha-1). the by-product yield of improved pattern was higher due to introduction and change of variety with improved technologies for the component crops. in both years it was revealed that the component crops wheat and jute of improved pattern produced valuable by-product. on the contrary, farmers are not able to sale by-product (rice straw) in the local market; whereas, the by-products of wheat and jute crops were valuable and high demand in the local market. rice equivalent yield also contributed more rice equivalent yield compared to farmers practice. the mean rice equivalent yield revealed that improved cropping pattern produced higher rice equivalent yield (13.51 t ha-1) over farmers’ traditional (7.29 t ha-1) cropping pattern (table 3). on an average, the rice equivalent and t. aman rice yield in improved pattern increased by 23.88 and 8.39%, respectively over the crops of the farmers’ practices (fp). inclusion of high yielding new varieties and crops with improved management practices in the improved pattern increased the t. aman rice equivalent yield. it was also due to higher price of components crops in the improved pattern. lower rice equivalent yield was obtained in the farmer’s pattern due to variety and traditional management practices. production efficiency maximum production efficiency was obtained from improved pattern in each year of 2013-2014 and 2014-15 (table 3). the higher production efficiency of improved cropping pattern might be due to introduction of new and or modern varieties and management practices. in conversely, the lowest production efficiency was observed in farmers’ pattern where modern management practices were absent. mean production efficiency (44.08) in terms of kg-1ha-1day was higher in improved pattern and lower (38.36) in farmers’ pattern. similar trend were noted by nazrul et al. (2013), khan et al. (2006), khan et al. (2005) and krishna and reddy (1997). land use efficiency land use efficiency is the effective use of land in a cropping year, which mostly depends on crop duration. the average land-use efficiency indicated that improved pattern used the land for 81% period of the year, whereas farmer’s pattern used the land for 50.69% period of the year. this higher land use efficiency in improved pattern is due to cultivation of wheat as component crop in fallow period. table 1. management practices of improved vsfarmer’s existing cropping pattern during 2013-15 91 on-farm assessment of system productivity of wheat-jute-t. aman rice cropping pattern in sylhet region parameters cropping pattern index farmer’s pattern (fp) improved pattern (ip) 2013-14 2014-15 2013-14 2014-15 variety c1 fallow fallow bari gom26 bari gom26 c2 br26 br26 cvl-1 cvl-1 c3 brri dhan33 brri dhan33 binadhan-7 binadhan-7 date of sowing/ transplanting c1 fallow fallow 20-25 nov 21-24 nov c2 10-15 may 10-15 may 4-7 april 4-8 april c3 12-15 august 12-14 august 5-10 august 5-10 august seed rate (kg ha-1) c1 fallow fallow 120 120 c2 30-35 30-35 7 7 c3 28-30 28-30 20-25 20-25 planting method c1 fallow fallow line line c2 line line line line c3 line line line line spacing (cm) c1 fallow fallow 30 cm in line 30 cm in line c2 20 × 10 20 × 10 20 cm in line 20 cm in line c3 20 × 15 20 × 15 20 × 15 20 × 15 fertilizer dose (npkszn, kg ha-1) c1 fallow fallow 120-30-6015-1 120-30-6015-1 c2 83-20-40-5-1 83-20-40-5-1 110-15-40-80.5 110-15-40-80.5 c3 92-24-60-80.5 92-24-60-80.5 115-35-40-40.5 115-35-40-40.5 fertilizer application method c1 fallow fallow all pkszn & ½ n as basal and rest n at 21 and 45dap all pkszn & ½ n as basal and rest n at 21 and 45dap c2 all pks used as basal during final land preparation. n used in 2 equal splits at 15-20 dat and another one in 35-40 dat. all pks used as basal during final land preparation. n 2 used in 2 equal splits at 1520 dat and another one in 35-40 dat. half of nitrogen and all other fertilizers applied as basal during final land preparation. remaining nitrogen was top dressed at 40-45 das under moist soil condition half of nitrogen and all other fertilizers applied as basal during final land preparation. remaining nitrogen was top dressed at 40-45 das under moist soil condition c3 all pks used as basal during final land preparation. n used in 2 equal splits all pks used as basal during final land preparation. n 2 used in 2 equal all pkszn used as basal and n used in 3 equal splits, the first one after 15dat, all pkszn used as basal and n 2 used in 3 equal splits, the first one after 15 dat, 92 m.i. nazrul parameters cropping pattern index farmer’s pattern (fp) improved pattern (ip) 2013-14 2014-15 2013-14 2014-15 at 15-20 dat and another one in 35-40 dat. splits at 1520 dat and another one in 35-40 dat. second one at 35-40 dat and third one at 5-7 days before panicle initiation stage. second one at 35-40 dat and third one at 5-7 days before panicle initiation stage. weeding (no.) c1 fallow fallow 1 1 c2 2 2 2 2 c3 1 1 2 2 irrigation/rainfed c1 fallow fallow 2-3 2-3 c2 rainfed rainfed rainfed rainfed c3 rainfed rainfed rainfed rainfed insect-pest control c1 fallow fallow ipm ipm c2 chemical chemical ipm ipm c3 chemical chemical ipm ipm harvest time (date) c1 fallow fallow 17-20 march 17-20 march c2 10-15 aug 10-15 aug 25-28 july 25-23 july c3 15-20 nov 15-20 nov 10-16 nov 10-15 nov field duration (days) c1 98-105 98-105 c2 85-90 85-90 100-108 100-108 c3 96-100 96-100 90-96 90-96 c1: fallow/wheat; c2: t. aus/jute, c3: t. aman; ipm: integrated pest management table 2. productivity of improved and farmer’s existing patterns during 2013-15. years cropping patterns grain/fiber yield (t ha-1) by product yield (t ha-1) fallow/ wheat t.aus/ jute t. aman wheat t. aus/ jute t. aman 2013-14 ip 3.83 2.31 4.13a 4.74 3.53 4.70 fp 3.92 3.75b 4.46 4.80 2014-15 ip 3.61 2.26 3.88a 4.76 3.34 4.85 fp 3.85 3.64a 4.38 4.51 mean ip 3.72 2.29 4.01a 4.75 3.43 4.77 fp 3.89 3.70b 4.42 4.65 fp = farmer’s pattern, ip = improved pattern. price of rice seed =26.00 tk. kg-1; wheat seed = 35.00 tk. kg-1; jute seed = 75.00 tk. kg-1; urea = 20.00 tk. kg-1; tsp =22.00 tk. kg-1; mop = 15.00 tk. kg-1. among field operations, the cost of plowing was taken as tk. 10 decimal-1, labour cost of tk. 300 man-1day-1. gross returns included income from sale of main and by-products (tk. ka-1) of all crops; price of t. aus rice = 19.00 tk. kg-1; t. aman rice = 20.50 tk. kg-1; jute fiber = 40.00 tk. kg-1; wheat straw/haulm= 1.00 tk. kg-1 and jute stick =5.00 tk. kg-1. sustainable yield index the values of sustainable yield index (syi) as a measure of sustainability of the system which was high in the improved cropping system over farmer’s practices (table 4). it was revealed from the experimental results that between two different cropping systems wheat-jute-t. aman rice recorded the highest syi of 76.41% followed by fallow-t. aus-t. aman rice (66.10%). it indicates that cropping system involving wheat in fallow period and jute instead of t. aus rice recorded higher syi compared to 93 on-farm assessment of system productivity of wheat-jute-t. aman rice cropping pattern in sylhet region fallow-rice based crop sequences. the results are in agreement with the findings of nazrul et al. (2013) and ram et al., (2012). this indicated that improved pattern is therefore, more stable than farmer’s pattern. wheat and jute are providing special advantage regarding utilization of fallow land and improving soil health, respectively. cost benefit analysis between two crop sequences, the improved cropping pattern showed its superiority over farmers’ existing pattern during two consecutive years of cropping. on an average, gross return of the improved pattern was tk.276955 ha-1 which was more than 85% higher than farmers’ pattern of tk. 149445 ha-1 (table 4). the production cost of the improved pattern (tk. 131457 ha-1) was higher than farmers’ pattern (tk. 85261 ha-1) due to introduction of wheat in fallow and cost of fertilizer and other inputs. the gross margin was substantially higher in the improved pattern (tk.145601 ha-1) than farmers’ pattern (tk. 64184 ha-1). inclusion of wheat and jute in these cropping systems besides, increasing the system productivity fetched higher market price thereby, increasing the gross margin. as a result, 126% additional gross margin was achieved by adding 54% additional cost in the improved pattern. returns per taka invested were highest for wheat-jute-t. aman rice (2.11) over the farmer’s pattern (1.75). table 3. rice equivalent yield, production efficiency, land use efficiency and sustainable yield index of improved and farmers patterns during 2013-15 years cropping patterns rice equivalent yield (t ha-1) production efficiency (kg ha-1 day-1) land use efficiency (%) sustainable yield index (%) 2013-14 ip 13.83 44.90 84.38 73.69 fp 7.38 38.84 52.05 67.26 2014-15 ip 13.20 43.27 78.91 79.12 fp 7.20 37.89 49.32 64.94 mean ip 13.51 44.08 81.65 76.41 fp 7.29 38.36 50.69 66.10 table 4. cost benefit analysis of improved and farmer’s existing cropping pattern during 2013-15 years cropping patterns gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr 2013-14 ip 283515 131957 151558 2.15 fp 1512900 85761 65529 1.76 2014-15 ip 270600 130957 139643 2.07 fp 147600 84761 62839 1.74 mean ip 276955 131457 145601 2.11 fp 149445 85261 64184 1.75 conclusion wheat jute t. aman rice cropping system was found more productive, sustainable, land-use efficient, and remunerative than the existing farmers cultivated patterns under eastern surma-kushiyara floodplain (aez-20) of bangladesh. . therefore, farmers of aez-20 could follow the wheat (var. bari gom-26) jute (var. cvl-1) t. aman 94 m.i. nazrul (var. binadhan-7) rice cropping system for higher system productivity and profitability in medium high land. acknowledgements authors are gratefully acknowledged bangladesh agricultural research institute, gazipur and metrological department, srimangal, moulvibazar for providing financial help and logistic support and weather data, respectively. thanks are resume who contributed compile and editing of the paper. references ahasan, m. n., m. a. m. chowdhury and d. a. quadir. 2010. variability and trends of summer monsoon rainfall over bangladesh. j. hydroly. and metor. 7(1): 1-16 alam, q. m., m. n. islam, a. k. m. h. haque and t. k. khudu. 1998. economic profitability of growing mustard/potato as an additional crop between two rice crops in bogora district of bangladesh. bangladesh j. agril. res. 23(4): 717-730. azad, a. k., f. a. h. talukdar, m. a. wahhab and m. a. khan. 1993. progress and prospect of jute based cropping systems research in bangladesh. proc. expert cons. jute and kenaf improvement: pp. 244-267. bbs (bangladesh bureau of statistics) 2001. year book of agricultural statistics of bangladesh. bangladesh bureau of statistics. 22nd edition, december 2003. hossain, m. a. and m. a. wahhab. 1992. demonstration-cum-assessment of recommended and farmer’s technologies in jute cultivation. abs. of research. argil. res. on jute, bangladesh jute research institute: p. 250. khan, m. a. h., m. a. quayyum, m. i. nazrul, n. sultana and m. r. a. mollah. 2005. on-farm evaluation of production potential and economics of mustard-rice based improved cropping system. j. socio. res. dev. 2(1): 37-42. krishna, a and k.a. reddy. 1997. production potential and economics of different rice (oryza sativa) based cropping system in andhra pradesh. india j. argil. sci. 67(12): 551-553. malavia, d. d., m. p. singh, m. m. vyas, j. c. patel and k. k. kalaria. 1986. production potential and economic feasibility of different crop sequences. indian j. argon. 31(1): 75-78. nazrul, m. i., shaheb, m. r., khan, m. a. h. and khan, a. s. m. m. r. 2013. onfarm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16(2): 41-50. ram, a. jat, r. a. dungrani, m. k. arvadia and kanwar l sahrawat. 2012. diversification of rice (oryza sativa l.) based cropping systems for higher productivity, resource-use efficiency and economic returns in south gujarat of india. arch. of agron.and soil sci. 58(6): 561-572. soni, p. n and r. kaur. 1984. studies on production potential of different cropping systems. indian j. agron. 29 (3): 367-78. tomer, s. s and a. s. tiwari. 1990. production potential and economics of different crop sequences. indian j. of agron. 35 (1, 2): 30-35. verma, s. p and s. c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9 (2): 89-92. bangladesh agron. j. 2015, 18(1): 113-119 optimization of herbicide teana 9ec dose for controlling weeds in brinjal s.k.paul1, s.mazumder2, t.a.mujahidi3, s.k.roy4 and s.kundu5 1agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh 2sher-e-bangla nagar adorsha mohila college, dhaka-1207, bangladesh 3plant breeding division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh 4department of genetics and plant breeding, sher-e-bangla agricultural university, dhaka-1207, bangladesh 5planning and evaluation division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. key words: herbicide, weed management, brinjal abstract an experiment was conducted at the research field of agronomy division, bangladesh agricultural research institute, joydebpur, gazipur during the rabi season of 20132014 to find out the optimum dose of herbicide (teana 9 ec) to control weeds in brinjal field for getting higher yield. six treatments, viz.: (i) teana 9 ec @ 750 ml ha-1 spraying on 15 das and 45 das, (ii) teana 9ec @1000 ml ha-1 spraying on 15 das and 45 das, (iii) teana 9ec @ 1250 ml ha-1 spraying on 15 das and 45 das, (iv) teana 9ec @ 1500 ml ha-1 spraying on 15 das and 45 das, (v) two hand weddings, and (vi) no weeding (control) were used in the experiment. among the weed species, bathua (chenopdium album), durba (cynodon dactylon), anguli (digitaria sanguinalis), helencha (jussiaea repens), hatishur (heliotropium indicum), shama (echinochola crusgalli), swetlomy (gnaphalium japonicum), mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (eleusine indica), bon masur (vicia sativa) were found dominant in wheat field. the result showed that the highest dry weight of weeds at 30 and 60 das were 12.24 and 24.12 gm-2 in control plot, whereas the lowest weed dry weight was observed in two hand weedings. the maximum weed control efficiency over control both at 30 and 60 das were 79.41 and 74.32%, respectively in the treatment with two hand weedings. the highest number of fruits plant-1, single fruit weight (g), fruit length (cm) and yield (t ha-1) was found in the treatment having two hand weedings and the lowest in no weeding (control). though the weed control efficiency (wce) was the highest in the treatment with two hand weedings due to higher labor cost but the maximum benefit cost ratio was the highest when teana 9ec @ 1500 ml/ha was sprayed two times on 15 and 45 das. introduction in crop production there are many causes of yield loss, of which weed is one of the most important one which also deteriorates the quality of crops (hasanuzzaman et al., 2007). weeds cause enormous losses to crops even more than other pests worldwide. oerke and dehne (1997) found that weeds cause around 33% of total crop loss in asia and other countries. on an average, 37.3% of crop produce is damaged by weeds in bangladesh (karim et al., 1998) that valued approximately tk. 59665.7 million (karim, 2008). production losses in bangladesh due to weeds as 33.2% in food crops, 41.3% in cereals, 31.9% in pulses, 40.8% in oilseed crops, 34.2% in fibre crops and 40.3% in rice (paul et al., 2015). hossain et al. (2012a) reported that the eighteen different weed species of which ten majors were observed much more serious to the crop. 114 paul et al. brinjal (solanum melongena l.) is one of the most important, widely and round the year cultivated popular vegetable crop in bangladesh. it grows well in winter season. but it can be grown in all seasons. though it is grown well year round, but weed decreases the yield drastically. there are many factors responsible for low yield, of which weed reduces its yield if not properly controlled (hasanuzzaman et al., 2008).crop management practices play an important role in crop production of which weed control is an important task which involves a lot of production cost due to unavailability of human labor in the world as well as bangladesh. as a result the alternate way to control weeds by the use of herbicide is gradually increased. the excess use of herbicide to control weeds is hazardous for health and causes environmental pollution. but lower doses cannot control the weeds properly. so, determination of optimum doses of herbicide is essential. the herbicides namely, teana 9ec is a selective herbicide and effective for control of most broad leaf and sedge weeds in brinjal field. it is assumed that teana 9ec may provide more effective, economic and easier solution for weed management in brinjal in comparison to manual weeding. considering the above facts, the trial was undertaken to determine the optimum doses of herbicide (teana 9ec) on weed control and subsequent growth and yield of brinjal. materials and methods the experiment was conducted at the agronomy research field of bangladesh agricultural research institute, gazipur during the period from november 2013 to may 2014. the land was medium high and the soil was clay loam in texture. six treatments viz., (i) teana 9ec @ 750 ml ha-1 spraying at 15 das (days after sowing) das and 45 das, (ii) teana 9ec @ 1000 ml ha-1spraying at 15 das and 45 das, (iii) teana 9ec @ 1250 ml ha-1spraying at 15 das and 45 das, (iv) teana 9ec @ 1500 ml ha-1spraying at 15 das and 45 das, (v) two hand weedings and (vi) no weeding were in the study. the unit plot size was 3m x 4m. the brinjal plant was transplanted on 26 november 2013. the brinjal field was fertilized with 80-60-4020 kg np2o5k2o -s ha-1. three irrigations were given at 21, 55 and 75 das. brinjal (cv. bari begun 10) seedlings were transplanted maintaining 75cm x 60 cm spacing. herbicides were sprayed with a knapsack sprayer as per treatment and all other operations were done as and when required. weed samples were collected at 30 and 60 das. data on yield components were taken and analyzed statistically using mstat-c program. the relative density (rd) and weed control efficiency (wec) were calculated by the following formula. relative density (rd) = 100 of weeds no. total species weedspecificof no weed control efficiency (wec) = 100 plot controlof wt.dry plot specificof wt.dry-plot controlof wt.dry results and discussion major weeds flora were found in the experiment plots i.e. bathua (chenopdium album), durba (cynodon dactylon), anguli (digitaria sanguinalis), helencha (jussiaea repens), hatishur (heliotropium indicum), shama (echinochola crus-galli), swetlomy (gnaphalium japonicum), mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (eleusine indica), bon masur (vcia sativa) (table 1). no. of weeds and relative density of 115 optimization of herbicide teana 9ec dose for controlling weeds in brinjal weeds were found maximum from sps. shama in all treatments except two hand weeding where maximum from weed species helencha (table 1). table 1. weed infestation in wheat field at 30 and 60 das during the 20132014 treatment weeds species no. of weeds / m2 relative density (%) local name scientific name 30 das 60 das 30 das 60 das t1= teana 9ec @ 750 ml ha-1 spraying at 15 and 45 das bathua chenopdium album (l.) 2 6 2.74 5.77 durba cynodon dactylon 14 17 19.18 13.46 anguli digitariasa nguinalis 3 6 4.11 5.77 helencha jussiaea repens 3 7 4.11 6.73 hatishur heliotropium indicum 1 3 1.37 2.88 shama echinochola crus-galli 25 32 34.24 30.77 bangchora 3 4 4.11 3.84 swelomy gnaphalium japonicum 0 1 0 0.96 mutha cyperus rotundus 3 7 4.11 6.73 shaknote amaranthus viridis 1 2 1.37 1.92 gaicha paspalum commersonii 2 1 2.74 0.96 chapra eleusine indica 16 18 21.92 17.31 bon masur vicia sativa 2 1.92 total 73 104 100 100 t2 = teana 9ec @ 1000 ml ha-1 spraying at 15 and 45 das bathua chenopdium album (l.) 1 2 2.13 2.78 durba cynodon dactylon 5 9 10.64 12.50 anguli digitaria sanguinalis 0 3 0 4.17 helencha jussiae arepens 6 12 12.76 16.67 hatishur heliotropium indicum 0 3 0 4.17 shama echinochola crus-galli 12 9 25.53 12.50 bangchora 0 2 0 2.98 swetlomy gnaphaliumj aponicum 5 7 9.6 8.86 mutha cyperus rotundus 11 14 18.41 19.64 shaknote amaranthus viridis 3 7 5.38 9.92 gaicha paspalum comersonii 1 3 2.13 4.37 chapra eleusine indica 6 4 12.76 6.11 bon masur vicia sativa 2 4 4.26 5.55 total 52 79 100 100 t3 = teana 9ec @ 1250 mlha-1spraying at 15 das and 45 das bathua chenopdium album (l.) 6 8 13.95 15.68 durba cynodon dactylon 5 6 11.65 11.76 anguli digitaria sanguinalis 2 3 4.65 5.89 helencha jussiae arepens 2 2 4.65 3.92 hatishur heliotropiu mindicum 2 3 4.65 5.89 shama echinochola crus-galli 10 8 23.25 15.68 bangchora 4 7 9.30 13.72 swetlomy gnaphalium japonicum 1 2 2.27 3.84 mutha cyperus rotundus 2 3 4.65 5.89 shaknote amaranthus viridis 3 3 6.98 5.89 gaicha paspalum commersonii 1 2.27 chapra eleusine indica 8 8 18.60 15.68 bon masur vicia sativa 1 3 2.32 5.89 total 45 54 100 100 t4 = teana 9ec @ 1500 mlha-1spraying bathua chenopdium album (l.) 1 2 4.55 6.90 durba cynodon dactylon 1 3 4.55 10.34 116 paul et al. treatment weeds species no. of weeds / m2 relative density (%) local name scientific name 30 das 60 das 30 das 60 das at 15 das and 45 das anguli digitaria sanguinalis 1 3 4.55 10.34 helencha jussiaea repens 5 3 22.72 10.34 hatishur heliotropium indicum 2 6.90 shama echinochola crus-galli 3 5 13.63 17.24 bangchora 1 4.55 swetlomy gnaphaliumj aponicum 2 6.90 mutha cyperus rotundus 6 5 27.27 17.24 shaknote amaranthus viridis 4 18.18 gaicha paspalum commersonii 2 6.90 chapra eleusine indica 5 17.24 bon masur vicia sativa 1 2 4.55 6.90 total 25 30 100 100 t5 = two hand weeding bathua chenopdium album (l.) 1 3 3.57 9.67 durba cynodon dactylon 1 2 3.57 6.45 anguli digitaria sanguinalis 1 1 3.57 3.22 helencha jussiaea repens 11 8 39.29 25.82 hatishur heliotropium indicum 1 2 3.57 6.45 shama echinochola crus-galli 1 3.22 bangchora 4 3 14.29 9.68 swetlomy gnaphalium japonicum 1 2 3.57 6.45 mutha cyperus rotundus 3 9.68 shaknote amaranthus viridis 4 14.29 gaicha paspalum commersonii 1 3.57 chapra eleusine indica 2 6 7.14 19.36 bon masur vicia sativa 1 3.57 total 28 31 100 100 t6 = no weeding bathua chenopdium album (l.) 7 9 6.14 5.45 durba cynodon dactylon 7 9 6.14 6.36 anguli digitaria sanguinalis 10 15 8.77 14.55 helencha jussiaea repens 6 8 5.26 7.28 hatishur heliotropium indicum 4 8 3.51 6.36 shama echinochola crus-galli 31 26 27.19 22.73 bangchora 14 2 12.29 1.81 swetlomy gnaphalium japonicum 1 2 0.88 1.81 mutha cyperus rotundus 8 12 7.01 10.91 shaknote amaranthus viridis 6 8 5.26 7.28 gaicha paspalum commersonii 2 2 1.75 0.91 chapra eleusine indica 12 10 10.54 10 bon masur vicia sativa 6 8 5.26 6.36 total 114 119 100 100 dry weights of weeds were significantly influenced by different weeding methods (table 2). the highest dry weight of weeds at 30 and 60 das were 12.24 and 24.12 gm-2 in control plot where lowest in two hand weedings. the maximum weed control efficiency over control both at 30 and 60 das were 79.41 and 74.32%, respectively in treatment two hand weedings. though the weed control efficiency (wce) was highest in two hand weedings but due to higher cost of labor, the maximum benefit cost ratio was highest in teana 9ec @ 1500 ml ha-1 spraying at 15 and 45 das. results were in agreement with hossain et al. (2012a), hossain et al. (2012b) and islam (2014). 117 optimization of herbicide teana 9ec dose for controlling weeds in brinjal table 2. dry weight and weed control efficiency in brinjal field at 30 and 60 das as affected by different doses of teana 9 ec treatments at 30 das at 60 das dry weight of weeds m-2 (g) weed control efficiency (%) dry weight of weeds m-2 (g) weed control efficiency (%) t1 = teana 9ec @ 750 ml ha-1spraying at 15 and 45 das 8.72 28.76 18.39 16.86 t2= teana 9ec @ 1000 ml ha-1spraying at 15 and 45 das 5.64 53.92 12.24 44.66 t3 = teana 9ec @ 1250 ml ha-1spraying at 15 and 45 das 3.12 74.51 7.76 64.91 t4 = teana 9ec @ 1500 ml ha-1spraying at 15 and 45 das 2.88 76.47 6.57 70.29 t5 = two hand weedings 2.52 79.41 5.68 74.32 t6 = no weeding 12.24 22.12 the maximum number of fruits plant-1, single fruit weight (g), fruit length (cm), yield (t ha-1) was found in two hand weedings followed by t4 and t3 treatment and lowest in no weeding. there was trend to increase yield with the increase of herbicides dose upto 1250 ml ha-1 (table 3). hossain (2013) reported that due to improper weed management crop losses occur from 3080%. in cereals and vegetables, hand weeding and use of mechanical weeder are often used, but now a day’s use of herbicides are expanding quickly due to labour shortage and commercialization. two hand weeding showed higher gross return but higher cost was involved in the treatment (table 4). as a result higher gross return was incurred from treatment t4 with higher benefit cost ratio (1.26). so, sustainable weed management is very much effective for friendly-environment and biodiversity (control). table 3. fruit yield and yield contributing characters of brinjal as affected by different weed management practices treatment fruit plant-1 (no.) single fruit weight (g) fruit length (cm) fruit yield (t ha-1) t1 = teana 9ec @ 750 ml ha-1 spraying at 15 and 45 das 11.05 86.48 24.09 14.56 t2 = teana 9ec @ 1000 ml ha1spraying at 15 and 45 das 14. 99 86.49 24.81 24.25 t3 = teana 9ec @ 1250 ml ha-1 spraying at 15 and 45 das 16.85 86.88 24.92 27.52 t4 = teana 9ec @ 1500 ml ha1spraying at 15 and 45 das 16.87 86.89 24.93 27.51 t5 = two hand weedings 17.36 87.53 24.91 28.47 t6 = no weeding 5.85 86.11 24.65 8.31 lsd (0.05) 0.59 2.66 0.16 1.28 cv (%) 1.79 1.61 0.33 2.37 118 paul et al. table 4. cost and benefit analysis of brinjal as influenced by different weed control management practice treatments gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 = teana 9ec @ 750 ml ha1spraying at 15 and 45 das 107,000 92,300 14,700 1.16 t2= teana 9ec @ 1000 ml ha1spraying at 15 and 45 das 111,000 92,500 18,500 1.20 t3 = teana 9ec @ 1250 ml ha1spraying at 15 and 45 das 114,400 92,700 21,700 1.23 t4 = teana 9ec @ 1500 ml ha-1 spraying at 15 and 45 das 116,600 92,900 23,700 1.26 t5 = two hand weedings 118,300 95,000 23,300 1.24 t6 = no weeding 95,000 89,900 5,100 1.06 conclusion from the above findings it may be concluded that teana 9ec herbicide could be effectively control weeds of brinjal. though the weed control efficiency (wce) was the maximum in the treatment with two hand weedings but involved higher labor cost as such, the maximum benefit cost ratio was obtained from herbicides teana 9ec @ 1500 ml/ha sprayed two times as on 15 and 45 das. references hasanuzzaman, m., k. nahar and m.r. karim. 2007. effectiveness of different weed control methods on the performance of transplanted rice. pak. j. weed sci. res. 13: 17-25. hossain, m. s., m. m.islam, a.t.m. m.alam, i.ahmed and m.j. alam. 2012b. species identification, density evaluation and green weight of weeds in deshi jute (corchoruscapsularisl.) growing areas of bangladesh. bangladesh j. weed sci. 3 (1&2): 47-52. hossain, m. s., m. m.islam, i. ahmed, a.t.m.m.alamand m.s. h. bhuiyan. 2012a. identification of species, density evaluation and green weight of weeds in tossa jute (corchorusolitoriusl.) growing areas of bangladesh. bangladesh j. weed sci. 3 (1&2): 1924. hossain, s.t. 2013. weed in bangladesh: issues and challenges. (key note paper), souvenir, 4thconference of weed science society of bangladesh, held on 03 may 2013 at bangladesh agril. res. council. pp. 22-28. http://www.ejournalofscience.org/download_april14_pdf_4.php islam, m. m. 2014. research advances of jute field weeds in bangladesh: a review. arpn j. sci. technol. 4(4): 254-268. karim, s. m. r. 2008. weeds and their impacts on biosecurity, environment and food security. key note paper of 1st national conference and seminar on weeds and food security, 8 november: 5-18. http://www.ejournalofscience.org/archive_april_2014.php 119 optimization of herbicide teana 9ec dose for controlling weeds in brinjal karim, s.m.r., t.m.t. iqbal and n. islam.1998. relative yields of crops and crop losses due to weed competition in bangladesh. pakistan j. sci. ind. res. 41(6): 318-324. oerke, e.c. and h.w. dehne.1997. global crop production and the efficiency of crop protection: current situations and future trends. european j. plant pathol. 103(3): 203-215. paul, s.k., t.a.mujahidi., m. h. khan., s.k. roy. and m.m. rahman. 2015. determination of the optimum doses of herbicide (teana 9ec) to control weeds in wheat field. bangladesh j. weed sci. 4 & 5:93-99. microsoft word 7. baj-226_revised.docx bangladesh agron. j. 2016, 19(1): 49-57 integrated approach for liming and fertilizer application on yield of cabbage and cauliflower in acidic soil of sylhet m. i. nazrul* and m. r. shaheb on-farm research division (ofrd), bangladesh agricultural research institute (bari), sylhet, bangladesh *corresponding authors: mi_nazrul@yahoo.com key words: acid soil, benefit cost ratio, cabbage, cauliflower, liming, dolomite abstract an experiment was conducted at farming system research and development (fsrd) site, jalalpur and multi location testing (mlt) sites, moulvibazar and zokigonj during 2013-2015 to study the effect of liming and fertilizers levels on the yield of cabbage and cauliflower in acidic soil of sylhet. trials were laid out in a factorial randomized block design with six dispersed replications. the treatments of fertilizer managements were m1: soil test based (stb) recommended fertilizer and m2: fertilizer dose practiced by the farmers (fp) and the level of limes were l1:0 t ha-1; l2: 1 t ha-1 and l3: 2 t ha-1. results revealed that yields of cabbage and cauliflower responded significantly to fertilizer doses, levels of lime, and their combinations in all the locations. soil test based fertilizer rate (m1-n201, p63, k65, s23, zn0.5 for cabbage and m1-n157, p57, k116, s20, zn0.5 kg ha-1 for cauliflower) gave the maximum head and curd yields of cabbage and cauliflower, respectively. the levels of lime at the rate 2 t ha-1 (l3) provided the highest yields of cabbage and cauliflower in all locations. dolomite lime @ 2 t ha-1 in combination with recommended fertilizer (m1l3) gave the highest yields and maximum economic returns of cabbage and cauliflower in all locations. however, it was identical with 1 t ha-1 of dolomite lime of similar dose of fertilizer nutrients. therefore, application of lime at the rate 1 t ha-1 with stb recommended fertilizer management (m1) could be enough for profitable economic returns for cultivating cabbage and cauliflower in strongly acidic soil in sylhet. introduction acidification of soils is an important challenge for some areas of bangladesh because of their adverse effects on soil fertility, crop production and food security. at present more than 30 per cent lands of this country have acidity constraint for crop production which is either very strongly acidic (ph < 4.5), strongly acidic (ph 4.5-5.5) or slightly acidic (ph 5.5-6.5) (frg, 2012). the sylhet regions are mostly under the agro-ecological zone 20 (eastern surma kushiyara floodplain) and the soils of this region are strongly acidic. the climate of this region is suitable for potato, tomato, cabbage, aroids and other vegetable production (nazrul and shaheb. 2014; nazrul et al., 2013a; nazrul et al., 2013b; shaheb et al., 2012; sarker, et al., 2012). in addition, agriculture is the only economic activity of most small farmers in this region. but strong soil acidity is an important factor that adversely affecting crop production. use of liming materials to correct the soil acidity is an important aspect of soil management practice. thus, lime application improved crop yields by eliminating the production constraints and favoring the production factors related to nutrient availability (shaheb et al., 2014; rahman et al., 2013; rahman et al., 2005). cabbage (brassica oleracea var. capitata) and cauliflower (brassica oleracea var. botrytis) are cole vegetables crops which are grown better in ph 6.06.8 (knott 1962), but eastern surma kushiyara 50 nazrul et al. floodplain soil is non-calcareous grey which have low ph (<5) so, liming is needed to increase ph for better performance of the crops. liming raises soil ph and reduces the toxic effect of al, fe and mn and increases the availability of p, mo, ca, and mg (bodruzzaman, 2010; frg, 2012). several other reports (mongia et al., 1998; rahman et al., 2000; rahman et al., 2002, and rahman et al., 2004) also suggest that liming eliminated the toxic effect of aluminum and manganese and increased the availability of several plant nutrients, such as ca, mg, p, n, and mo. numerous researches have confirmed the positive impact of liming on yield of some crops (rastija et al., 2010; shaheb et al., 2014; rahman et al., 2013; rahman et al., 2005). at present, farmers in this area use agricultural lime or dolomite in different quantities to correct the soil acidity. but, initial high cost involvement in liming practice makes exploring the benefit of liming difficult for the marginal growers. the experiments were therefore, designed to find out the suitable levels of dolomite lime and fertilizer management options for better yield of cabbage and cauliflower in acidic soils under the aez 20 of sylhet region. materials and methods an experiment was conducted under farmer’s fields located at fsrd site, jalalpur and mlt sites, moulvibazar and zokigonj during 2013-2015 to study the effect of lime and fertilizer on the yield of cabbage and cauliflower in acidic soil of sylhet. the study area lays 24070' n latitude and 91067' e longitude under the surma‐kusiyara floodplain of bangladesh. before starting the experiment, initial soil samples were collected from each farmer’s field and analyzed in the laboratory of soil resource and development institute, sylhet. type of experimental soil is non-calcareous grey with low organic matter content (1.29%), low soil ph (4.2-5.1), very low total n (0.06%), low content of p (8.59µg/g soil), k (0.13meq/100g soil) and s (9.14 µg/g soil) where as zn (1.22 µg/g soil) and b (0.48 µg/g soil) medium and optimum, respectively. trials were laid out in a factorial randomized block design with six dispersed replications where 2 fertilizer managements levels were m1soil test based (stb) recommended fertilizer and m2fertilizer dose practiced by the farmers (fp) and 3 level of limes viz., l10 t ha-1, l21 t ha-1 and l32 t ha-1 as treatment variables. the dolomite lime (cao = 30 %, mgo = 22% and co2= 48%) was applied 15-20 days before planting with spread method on the top of the soil and then incorporate with the soil depth at 25 cm by plough. the crops wise fertilizers nutrients n p k s zn (cabbage m1: 201-63-6523-0.5, m2: 220-70-70-40-0 and cauliflower m1: 157-57-116-20-0.5, m2: 170-43-136-0-0 kg ha-1) were calculated as per the initial nutrient status of the experimental soil and average fertilizer doses practiced by 25 farmers. fertilizers were applied in the form of urea, tsp, mop, gypsum and zinc sulphate, respectively. half of urea and all other fertilizers were applied and mixed with soil at the time of final land preparation. rest urea was top dressed at 25 days after transplanting. seedlings of cabbage (var. atlas-70) and cauliflower (var. canditcharm) at the age of 30 days were planted on a plot size of 5 m x 4 m with plant spacing of 60 cm x 40 cm. the crops were harvested 80-95 days after planting (dap). twice irrigations one of each at 25 days interval from the transplant of seedlings; one weeding at 20 dap; two sprayings of secure fungicide @ 1.5ml-1 of water for controlling blight of crops. all intercultural operations were done as when necessary. the head and curd yield of cabbage and cauliflower were recorded from 10 randomly selected plants from each plot and yield of crops were recorded from whole plot basis at harvest. the recorded data were statistically analyzed and mean values were separated by least significant difference test (lsd). all types of variable costs of production were recorded and cost-benefit analysis was carried out (heady and dhillon, 1988). 51 integrated approach for liming and fertilizer application on yield of cabbage and cauliflower results and discussions location: jalalpur head yield of cabbage: results revealed that significant response was found on fertilizer management and application of lime and their interactions on the head and curd yields of cabbage and cauliflower respectively. the average maximum head yield of cabbage (65.01 t ha-1) was recorded in soil test based (stb) (m1) compared to fertilizer dose of the farmers (m2). the maximum head yield (66.22 t ha-1) of cabbage was found in 2 t ha-1 of dolomite (l3) that was followed by 1 t ha-1 (l2) of dolomite lime. khandakhar et al., (2004) also reported that @2 t ha-1 of ca (oh)2 along with 100 kg k ha-1 is recommended for potato cultivation under strongly acidic soil. whole non-liming treatment produced the lowest yield (56.04 t ha-1) of cabbage. the results revealed that combined effect of stb and 2 t ha-1 of dolomite lime (m1l3) provided the maximum average head yield of cabbage (70.90 tha-1) that was statistically followed by m1l2 with yield of 66.49 t ha-1(table 1). table 1. effect of fertilizer management and levels of liming on the head and curd yield of cabbage and cauliflowerat jalalpur, sylhet (2013-2015) head yield (t ha-1) curd yield (t ha-1) treatments 2013-2014 2014-2015 average 2013-2014 2014-2015 average a. fertilizer management m1 67.71 62.30 65.01 44.39 60.40 52.4 m2 62.24 54.69 58.47 43.88 49.08 46.48 cv (%) 2.53 8.87 5.70 4.33 12.97 8.65 b. level of liming l1 58.46 53.61 56.04 40.90 53.93 47.42 l2 67.16 58.75 62.96 43.59 53.71 48.65 l3 69.31 63.12 66.22 47.92 56.57 52.25 cv (%) 2.53 8.87 5.7 4.33 12.97 8.65 lsd (0.05) 2.48 7.82 5.15 5.81 ns 5.81 fertilizer management × level of liming m1l1 59.55 55.67 57.61 40.25 59.26 49.76 m1l2 70.50 62.48 66.49 43.25 58.32 50.79 m1l3 73.07 68.73 70.9 49.66 63.61 56.64 m2l1 57.37 51.55 54.46 41.55 48.61 45.08 m2l2 63.83 55.02 59.43 43.93 49.10 46.52 m2l3 65.54 57.50 61.52 46.17 49.52 47.85 cv (%) 2.53 8.87 5.7 4.33 12.97 8.65 lsd (0.05) 2.48 7.82 5.15 2.88 10.70 6.79 m1: soil test based (stb) recommended fertilizer and m2: fertilizer dose practiced by farmers (fp) and level of limes l1: 0 t ha-1, l2: 1 t ha-1 and l3: 2 t ha-1 curd yield of cauliflower: the stb fertilizer dose (m1) provided higher curd yield of cauliflower (52.40 tha-1) as compared to yield of the farmers (m2). considering the application of lime doses, the highest average curd yield (52.25 t ha-1) of cauliflower was found in 2 t ha-1 of dolomite lime (l3) that was followed by l2 (48.65 t ha-1). but, the lowest 52 nazrul et al. yield (47.42 t ha-1) was observed in l1 (zero liming). application of dolomite could increase soil ph from 4.9 to 5.4 with increase ca and mg stock in the soil (oliveira et al., 2003; thompson and kelly 1957). the situation made cauliflower to perform good vegetative growth because it is sensitive on ph level and high dose of mg reported by thompson and kelly (1957). the combined application of stband 2 t ha-1 of dolomite lime (m1l3) gave the maximum curd yield of cauliflower (56.64 t ha-1) which was statistically identical to m1l2 (50.79 t ha-1). however, the lowest curd yield (45.08 t ha-1) of cauliflower was produced by the treatment combination of m2l1 (table 1). cost and return analysis: the gross return, total cost and net return of different combinations are presented in table 2. from the cost benefit analysis, it was exhibited that maximum gross return (tk. 567200 and tk. 566400 ha-1) and net return (tk. 385777 and tk. 401067 ha-1) was obtained from the combination of m1l3 for cabbage and cauliflower, respectively. the lowest values of the same economic parameters were observed in combination of m2l1 (table 2). the economic analysis also revealed that the highest values (3.13 and 3.43) of benefit cost ratio (bcr) were obtained in case of both vegetables under the same treatment (m1l3). table 2. cost and return analysis of fertilizer management with levels of limes on the yield of cabbage and cauliflower at jalalpur in sylhet (2013-2015) cabbage cauliflower treatments gr (tk.ha-1) tc (tk.ha-1) ( gm (tk.ha-1) bcr gr (tk.ha-1) tc (tk.ha-1) gm (tk.ha-1) bcr m1l1 460880 172123 288757 2.68 497600 156033 341567 3.19 m1l2 531920 177023 354897 3.00 507900 160933 346967 3.16 m1l3 567200 181423 385777 3.13 566400 165333 401067 3.43 m2l1 435680 166268 269412 2.62 450800 153638 297162 2.93 m2l2 475440 171168 304272 2.78 465200 158538 306662 2.93 m2l3 492160 175568 316592 2.80 478500 162938 315562 2.94 gr: gross return (tk.ha-1), tc: total cost (tk.ha-1) and gr: gross margin (tk.ha-1) price of input and output (tk.kg-1): dolomite lime5.00, urea-20.00, tsp-22.00, mop-15.00, cowdung-1.00, cabbage-8.00, cauliflower-10.00 location: zokigonj it was observed that the doses of fertilizer management and dolomite levels and their interactions on the head and curd yield of cabbage and cauliflower were influenced significantly.(table 3). head yield of cabbage: the average head yield (66.58 t ha-1) of cabbage with stb fertilizer dose t was higher than cabbage fertilized with farmer’s practices. among the dolomite levels, 2 tha-1 (l3) contributed the maximum head yield (68.05 t ha-1) of cabbage which was statistically identical to 1 t ha-1 (l2) of dolomite. non liming treatment (l1) produced the lowest average head yield of cabbage (60.84 t ha-1). it was found that combination of stb recommended fertilizer management and 2 t ha-1 of dolomite limes (m1l3) gave the maximum head yield of cabbage (71.25 tha-1) that was statistically followed by m1l2 with yield of 65.92 t ha-1.it was reported that liming material increases the cation exchange 53 integrated approach for liming and fertilizer application on yield of cabbage and cauliflower capacity of soil and also increase nutrient content such as p and k (kisic et al., 2004b). it was assumed that application of dolomite lime increase soil ph; which helps to improve nutrients for the vegetables resulted increased the growth and yield of cabbage. curd yield of cauliflower: the average higher curd yield of cauliflower (49.42 t ha-1) was recorded in stb recommended fertilizer (m1) compared to farmers practice (m2). on the contrary, significantly higher curd yield (50.83 t ha-1) of cauliflower was produced by l3 compared to l2 and without lime. results of combined application of stb recommended fertilizer management and 2 t ha-1 of dolomite showed that the highest curd yield of cauliflower (54.90 t ha-1) was recorded that was statistically followed by m1l2 (47.93 t ha-1). however, the treatment combination (m2l1) was provided the lowest curd yield (40.69 t ha-1) of cauliflower (table 3). table 3. effect of fertilizer management and level of liming on the head and curd yield of cabbage and cauliflower, respectively at zokigonj in acidic soil of sylhet (20132015) head yield curd yield treatment s 2013-2014 2014-2015 average 2013-2014 2014-2015 average a. fertilizer management m1 63.72 69.44 66.58 50.03 48.81 49.42 m2 60.61 62.44 61.525 43.64 43.14 43.39 cv (%) 1.80 8.24 5.02 8.91 2.67 5.79 b. level of liming l1 60.00 61.67 60.84 43.90 42.22 43.06 l2 62.58 64.00 63.29 46.33 44.33 45.33 l3 63.92 72.17 68.05 50.28 51.38 50.83 cv (%) 1.80 8.24 5.02 8.91 2.67 5.79 lsd (0.05%) ns 9.89 9.89 ns 2.23 2.23 fertilizer management × level of liming m1l1 61.17 64.00 62.59 46.43 44.43 45.43 m1l2 63.50 68.33 65.92 49.33 46.53 47.93 m1l3 66.50 76.00 71.25 54.33 55.47 54.90 m2l1 58.83 59.33 59.08 41.37 40.00 40.69 m2l2 61.67 59.67 60.67 43.33 42.13 42.73 m2l3 61.33 68.33 64.83 46.23 47.30 46.77 cv (%) 1.80 8.24 5.02 8.91 2.67 5.79 lsd (0.05%) 2.04 9.89 5.965 7.59 2.23 4.91 m1: soil test based (stb) recommended fertilizer and m2: fertilizer dose practiced by farmers (fp) and level of limes l1: 0 t ha-1, l2: 1 t ha-1 and l3: 2 t ha-1 cost and return analysis : dolomite, 2 t ha-1 with fertilizer nutrients n201, p63, k65, s23, zn0.5 and n157, p57, k116, s20, zn0.5 kg ha-1 was contributed the highest net returns (tk. 426577 and tk. 383667 ha-1) from cabbage and cauluflower, respectively (table 4). fertilizer package practiced by the farmers without lime application provided lowest economic profit of both vegetables. 54 nazrul et al. table 4. cost and return analysis of fertilizer management with levels of limes on the yield of cabbage and cauliflower at zokigonj, sylhet (2013-2015) cabbage cauliflower treatments gr (tk.ha-1) tc (tk.ha-1) gm (tk.ha-1) bcr gr (tk.ha-1) tc (tk.ha-1) gm (tk.ha-1) bcr m1l1 500720 172123 328597 2.91 454300 156033 298267 2.91 m1l2 527360 177023 350337 2.98 479300 160933 318367 2.98 m1l3 570000 181423 388577 3.14 549000 165333 383667 3.32 m2l1 472640 166268 306372 2.84 406900 153638 253262 2.65 m2l2 485360 171168 314192 2.84 427300 158538 268762 2.70 m2l3 518640 175568 343072 2.95 467700 162938 304762 2.87 gr: gross return (tk.ha-1), tc: total cost (tk.ha-1) and gm: gross margin (tk.ha-1) price of input and output (tk.kg-1): dolomite lime5.00, urea-20.00, tsp-22.00, mop-15.00, cowdung-1.00, cabbage-8.00, cauliflower-10.00 location: moulvibazar head yield of cabbage: fertilizer application affected head yield of cabbage where maximum head yield (62.89 t ha-1) was produced by stb fertilizer management (m1) compared to farmers dose (m2). the head yield of cabbage was increased by increasing the rates of limewhere 2 tha-1 produced higher yield than the other rate of lime and no liming. the stb recommended fertilizer management with 2 t ha-1 of dolomite lime (m1l3) produced maximum head yield (65.49 t ha-1) that was followed by m1l2 (64.88 t ha-1), while the lowest head yield (51.59 t ha1) was gained in the treatment combination of m2l1 (table 5). sultana et al., (2009) reported that the grain yield of wheat was increased due to application of 2.0 t ha-1 lime at low soil ph (> 6.0). curd yield of cauliflower: it was observed that the effect of fertilizer management on the curd yield of cauliflower was significant. the higher curd yield (45.31t ha-1) was recorded in stb recommended fertilizer management (m1) compared to farmers dose (m2) (39.33 tha-1) although yields were non-significant. the level of dolomite, 2 t ha-1 (l3) gave the maximum curd yield (45.67 t ha-1) which was statistically followed by 1 t ha-1 (l2) of dolomite lime. on the contrary, the lowest curd yield (39.57 t ha-1) of cauliflower was observed in without lime (l1).the interacxtion result showed that the maximum average curd yield (48.88 t ha-1) was recorded in m1l3 that was statistically followed by m1l2 (44.56 t ha-1)while lowest yield (36.66 t ha-1) from farmers practice without dolomite.(table 5). table 5. effect of fertilizer management and level of liming on the head and curd yield of cabbage and cauliflower, respectively at moulvibazar in acidic soil of sylhet (20132015) head yield curd yield treatment s 2013-2014 2014-2015 average 2013-2014 2014-2015 average a. fertilizer management 55 integrated approach for liming and fertilizer application on yield of cabbage and cauliflower m1 66.16 59.62 62.89 50.00 40.61 45.31 m2 57.52 53.70 55.61 46.40 32.25 39.33 cv (%) 6.48 3.34 4.91 5.85 8.73 7.29 b. level of liming l1 56.31 53.57 54.94 45.38 33.75 39.57 l2 65.13 56.17 60.65 47.67 35.77 41.72 l3 64.07 60.23 62.15 51.55 39.76 45.67 cv (%) 6.48 3.34 4.91 5.85 8.73 7.29 lsd (0.05%) 7.29 3.45 5.37 ns ns ns fertilizer management × level of liming m1l1 59.81 56.78 58.30 46.45 38.47 42.46 m1l2 60.27 59.48 59.88 49.43 39.69 44.56 m1l3 68.38 62.59 65.49 54.10 43.65 48.88 m2l1 52.81 50.37 51.59 44.30 29.02 36.66 m2l2 59.98 52.85 56.42 45.90 31.85 38.88 m2l3 59.76 57.87 58.82 49.00 35.87 42.44 cv (%) 6.48 3.34 4.91 5.85 8.73 7.29 lsd (0.05%) 7.29 3.45 5.37 5.13 5.78 5.455 m1: soil test based (stb) recommended fertilizer and m2: fertilizer dose practiced by farmers (fp) and level of limes l1: 0 t ha-1, l2: 1 t ha-1 and l3: 2 t ha-1 cost and return analysis : the cost benefit analysis exhibited that maximum gross return (tk. 523920 and tk. 488800 ha-1) and net return (tk. 342497 and tk. 323467 ha-1) was obtained from the treatment combination of stb recommended fertilizer management with dolomite 2 t ha-1 (m1l3) with higher benefit cost ratios (2.89 and 2.96) for cabbage and cauliflower, respectively. however, the treatment combinations without lime (m1l1, m2l1) contribute lower economic returns (table 6). table 6. cost and return analysis of fertilizer management with levels of lime on the cultivation of cabbage and cauliflower at moulvibazar, sylhet (2013-2015) cabbage cauliflower treatments gr (tk.ha-1) tc (tk.ha-1) gm (tk.ha-1) bcr gr (tk.ha-1) tc (tk.ha-1) ( gm (tk.ha-1) bcr m1l1 466400 172123 294277 2.71 424600 156033 268567 2.72 m1l2 519040 177023 342017 2.93 445600 160933 284667 2.77 m1l3 523920 181423 342497 2.89 488800 165333 323467 2.96 m2l1 412720 166268 246452 2.48 366600 153638 212962 2.39 m2l2 435360 171168 264192 2.54 388800 158538 230262 2.45 m2l3 470560 175568 294992 2.68 424400 162938 261462 2.60 gr: gross return (tk.ha-1), tc: total cost (tk.ha-1) and gm: gross margin(tk.ha-1) price of input and output (tk.kg-1): dolomite lime5.00, urea-20.00, tsp-22.00, mop-15.00, cowdung-1.00, cabbage-8.00, cauliflower-10.00 conclusion the results revealed that the maximum head yield of cabbage and curd yield of cauliflower was obtained with the application of stb recommended fertilizer (n201, p63, k65, s23, zn0.5 for cabbage and n157, p57, k116, s20, zn0.5 kg ha-1 for cauliflower). liming at the rate 2 t ha-1 supported for the highest yields of cabbage and cauliflower in both the years in all the locations but identical to that of 1 t ha-1of dolomite lime with similar dose of fertilizers therefore, application of lime at the rate 1 t ha-1 with recommended fertilizer might be 56 nazrul et al. effective for economic productivity of both the cabbage and cauliflower in the acidic soils of the greater sylhet region. references bodruzzaman, m. 2010. lime requirement of acid soils for sustainable crop production. ph. d. thesis. bau, mymensingh, bangladesh. p. 310. frg. 2012. fertilizer recommendation guide, bangladesh agriculture research council (barc), farmgate, dhaka 1215. p. 274. heady, e. o. and j. l. dillon. 1988. agricultural production functions. kalyani publishers. new delhi, india. khandakhar, s. m. a. t., m. m. rahman, m. j. uddin, s. a. k. u. khan and k. g. quddus. 2004. effect of lime and potassium on potato yield in acid soil. pak. j. biol. sci., 7(3): 380383. kisic i., b. ferdo, m. mesic, a. butaroc and z. vadic. 2004b. the effect of fertilization and liming on some soil chemical properties of eutric gleysol. agric. cosnspec. sci. 69(2-3): 43-49. knott, j. e. 1962. hand book for vegetable grower. john wiley & sons, inc. new york. meda a. r., m. a. pavan, m. e. cassiolato and m. miyazawa. 2002. dolomite lime’s reaction applied on the surface of a sandy soil of the northwest parana, brazil. braz. arch. biol. technol. 45(2): 219-222. mongia, a. d., n. t. singh, l. n. mandal and a. guha. 1998. effect of liming, superphosphate and rock phosphate application to rice on the yield and uptake of nutrients on acid sulphate soils. j. indian soc. soil sci. 46: 61-66. nazrul, m i., m. r. shaheb and j. u. sarker. 2013a. performance of bari released aroid varieties in surma kushiyara flood plain soil. bangladesh agron. j. 16 (1):39-44. nazrul, m. i. and m. r. shaheb. 2014. performance of sweet gourd as relay with transplanted aman rice under rainfed ecosystem in sylhet region. bangladesh agron. j. 17(2): 47-53. nazrul, m. i., m. r. shaheb, m. a. h. khan and a. s. m. m. r. khan. 2013b. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16 (2): 41-50. oliveira, p. p. a., a. e. boaretto, p. c. o. trivelin, w. s. de oliveira and m. corsi. 2003. liming and fertilization to restore degraded brachiaria decumbens pastures grown on an entisol. sci. agric. 60(1): 125-131. rahman, m. a., c. a. meisner, j. m. duxbury, j. lauren and a. b. s. hossain. 2002: integrated approach of liming and nutrient management to improve the productivity of acidic soil within a rice-wheat cropping system. poster no.773, symposium no. 05, 17th world congress of soil science. 14-21 august 2002. bangkok, thailand. rahman, m. a., j. chikushi, j. g. lauren, j. m. duxbury and c. a. meisner. 2004: liming and nutrient management for sustainable productivity of acidic alluvial soils under rice-wheat cropping system in bangladesh. proc. 6th international symposium on plant-soil interaction at low ph. pp. 304-305. august 1-5, 2004. sendai, japan. organized by international steering committee on soil-plant interaction at low ph. rahman, m. a., j. chikushi, j. g. lauren, j. m. duxbury, c. a. meisner, and e. yasunaga. 2005. chemical control of soil environment by lime and nutrients to improve the productivity of 57 integrated approach for liming and fertilizer application on yield of cabbage and cauliflower acidic alluvial soils under rice-wheat cropping system. environ. control biol. 43(4): 259266. rahman, m. a., m. bodruzzaman, a. j. m. s. karim, m. a. razzaque and c. a. meisner. 2000. effect of lime and phosphorus on soil ph, available p in soil and yield of wheat in acid soil of dinajpur. ann. bangladesh agric. 10(2):125-131. rahman, m. a., n. c. d. barma, m. h. sarker, m. m. r. sarker and m. i. nazrul. 2013. adaptability of wheat varieties in strongly acidic soils of sylhet. bangladesh j. agric. res. 38(1): 97-104. rastija, m., d. šimić and a. lalić. 2010. impacts of liming with dolomite on maize, wheat and barley yields. novenytermeles 59(suppl.): 65-68. sarker, m. m. r., m. r. shaheb and m. i. nazrul. 2012. urea super granule: a good source of nitrogen on growth yield and profitability of cabbage in sylhet. j. environ. sci. natural resources. 5(1): 295-299. shaheb, m. r., m. i. nazrul and m. a. rahman. 2014. production potential and economics of wheat as influenced by liming in north eastern region of bangladesh. asian j. agric. biol. 2(2): 152-160. shaheb, m. r., m. i. nazrul and m. h. sarker. 2012. performance of tomato varieties as affected by different planting dates in the north-eastern region of bangladesh. bangladesh agron. j. 15(2): 53-58. sultana, b. s., m. m. mian, m. r. islam, m. m. rahman, b. c. sarker and m. s. zoha. 2009. effect of liming on soil properties, yield and nutrient uptake by wheat. world environ. 4(1): 39-47. thompson, h. c. and w. c. kelly. 1957. vegetable crops. mcgraw-hill book co., new york. p. 611. microsoft word 10. baj-232_revised.docx bangladesh agron. j. 2016, 19(1): 81-86 effect of variety and seed rate on yield performance of mungbean under strip tillage system md. moshiur rahman1, taslima zahan2*, ms ali1, m begum1 and rw bell3 1bangladesh agricultural university, mymensingh, bangladesh 2bangladesh agricultural research institute, gazipur, bangladesh 3murdoch university, australia *corresponding author: taslimazahan_tzp@yahoo.com key words: seed rate, minimum tillage system, mungbean, machine seeding abstract a study was conducted at bangladesh agricultural university, mymensingh during march-june, 2013 to evaluate the performance of mungbean varieties and to determine the optimum seed rate under strip tillage system. three mungbean varieties (bari mung-6, binamung-5 and binamung-8) were tested against five seeding rates (20, 25, 30, 35 and 40 kg ha-1). the experiment was laid out in splitplot design with three replications. the study revealed that variety and seed rate had significant effect on plant population, pods plant-1, pod length, seeds pod-1, seed yield and stover yield of mungbean. the highest seed yield was obtained from bina mung-5 at 35 kg seed ha-1 while the highest stover yield was obtained from 40 kg seed ha-1. for bari mung-6 and binamung-8, 35 kg seed ha-1 also provided higher seed yield than other seeding rates. nevertheless, the lowest seed and stover yields were obtained from bina mung-8 with 20 kg seed ha-1. therefore, the study concluded that machine seeding of mungbean at 35 kg seed ha-1 ensure optimum seed yield for tested varieties under strip tillage system and cultivation of bina mung5 at 35 kg seed ha-1 can produce the maximum seed yield under this system. introduction mungbean (vigna radiata l.) is one of the most important pulse crops of bangladesh. the total production of mungbean in bangladesh was 32,000 metric tons from an area of 39,285 ha of land with average yield about 0.81 t ha-1 during 2013-14 (bbs, 2016). the crop has already been transformed from a marginal to major crop for its additional benefits like enhancing soil fertility, improving rural household income, employment opportunities, diversifying diets and increasing nutritional security (shanmugasundaram et al., 2009). the short-growth duration variety of mungbean is well fitted in rice-based cropping systems of asia. but our country is facing an acute shortage of mungbean due to low yield of 654.4 kg ha-1 (moa, 2012) and less production area. the reasons of low yield may be lack of high yielding varieties and some agronomicmanagement practices.generally mungbean is cultivated with conventional tillage that requires considerable fuel, labour and time. besides conventional tillage leads to soil erosion resulting soil fertility depletion. on the other hand, strip tillage offers potential to reduce soil erosion though a narrow strip of about six inches wide and four to eight inches deep is made in a single pass that helps to conserve soil moisture and consequently ensures similar soil temperature to conventional tillage systems (nowatzki et al., 2011; endres and hendrickson, 2010). seeding of mungbean in a strip by a machine reduces use of fuel and production cost by reducing the number of field passes and additionally, fertilizer can be applied at the same time of seeding with same machine. seed rate is one of the most important factors to achieve satisfactory yield. due to different seed size and weight, seed rate often may vary with mungbean varieties which significantly 82 rahman et al. influence yield of mungbean (taj et al., 2003). for machine seeding, it is important to adjust appropriate seed rate of mungbean for different varieties under strip tillage system. therefore, the study was taken to examine the performance of mungbean varieties under strip tillage system and to determine the optimum seeding rate for those varieties to obtain maximum yield. materials and methods the study was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh from march to june 2013. the experimental site is located at 24o75´ n latitude and 90o50´ e longitude in the south-west part of brahmaputra at an elevation of 18 m above the sea level. the site belongs to non-calcareous dark grey floodplain soil under the agro-ecological zone old brahmaputra floodplain “aez-9” (undp and fao, 1988). the experimental field was well drained medium high land with silt loam soil in texture having soil ph of 6.8. the organic matter content of the experimental field was 1.3%. the climate of the experimental site was under the subtropical region characterized by high temperature, high relatively humidity and heavy rainfall with occasional gusty winds during the experimental period. climate data during the study period were presented in table 1. three promising mungbean varieties viz. bari mung-6, binamung-5 and bina mung-8 were evaluated against five seed rates (20, 25, 30, 35 and 40 kg ha-1) in a split-plot design with three replications. seeds of three mungbean varieties were sown in the experimental field by a two wheel tractor machine named versatile multi-crop planter (vmp) maintaining the seed rates as per experimental specification. before one week of sowing the seeds, the preplanting herbicide roundup® (glyphosate) was applied in the whole field @ 75 ml/10 l water. seeds of mungbean were inoculated by rhizobial bio-fertilizer @ 100 g kg-1 of seeds just before sowing. di-ammonium phosphate (dap) and muriate of potash (mp) were applied to supply of phosphorus and potassium @ 80 and 40 kg ha-1, respectively during along with sowing seed on 27 march 2013 by vmp. seeds were placed by vmp at about 3-4 cm depth from the soil surface apart from 30 cm to row distance. number of weed population was counted randomly selected 2 spots of 1 m2 area. after counting, weeds were cut at the level of ground, cleaned with fresh water and dried in oven at 60o c for 72 hours. at maturity, pods were harvested from 02 june to 23 june, 2013. the data on number of plants m-2, plant height, total number of pods plant-1, pod length, number of seeds pod-1 were recorded from randomly selected five plants from outside of the harvested area. collected data were analysed and means were compared by duncan’s multiple range test (dmrt) using statistical program mstat-c. table 1. monthly record of air temperature, rainfall and relative humidity of the experimental site during march to june 2013 average air temperature (oc) months max. min. mean total rainfall (mm) average relative humidity (%) march’13 31.9 19.6 25.6 21.0 73.9 april’13 32.5 22.5 27.5 68.2 77.2 may’13 30.4 23.9 27.2 282.9 84.5 june’13 33.1 26.5 29.8 236.2 82.1 source: weather yard, department of irrigation and water management, bau, mymensingh results and discussions 83 effect of variety and seed rate on yield performance of mungbean under strip tillage system plant population plant population of mungbean at 20 days after sowing (das) was significantly affected by variety, seed rate and their interaction (figure 1a, 1b and 2). among the three varieties, the highest number of plant population (70.80) was obtained from bina mung-5 while the lowest value (39.93) from bari mung-6. in case of five seed rates, the highest number of plant population (89.78) was observed in 40 kg seed ha-1 seed rate whereas the lowest number of plant population (23.78) from 20 kg seed ha-1 .from the interaction, the highest number of plant population was found from bina mung-5 seeding at 40 kg ha-1 rate and the lowest number of plant population was counted from bari mung-6 at 20 kg seed ha-1 therefore, the study results indicated that plant population of mungbean increased with increasing seed rate. dainavizadeh and mehranzadeh (2013) also agreed that plant population increased significantly with increasing seed rate of mungbean. fig. 1. effect of (a) variety and (b) seed rate on plant population at 20 days after sowing of mungbean under strip tillage system yield and yield contributing characters yield contributing characters like number of pods plant-1, pod length, number of seeds pod-1 and 1000-seed weight were significantly affected by variety and seed rate of mungbean as well as seed and stover yields (table 2 and 3). the highest number of pods plant-1 (40.73), pod length (8.08 cm), seed yield (888.17 kg ha-1) and stover yield (1874.25 kg ha-1) were obtained from bina mung-5. whilst, the highest number of seeds pod-1 (9.68) and 1000-seed weight (37.14) were obtained from bari mung-6. in case of seed rate, the highest number of pods plant-1 (40.3) was counted from 20 kg seed ha-1 and the lowest value (33.0) from 40 kg seed ha-1. this might be happened due to the variation in number of plant population. low plant population may influence to produce more pods plant-1 and therefore, the inverse result can be found in case of high plant population of mungbean. similar results reported by taj et al. (2003) and mackenzie (1985) that number of pods per plant decreased in mungbean with increasing number of plant population. on the other hand, the highest pod length (8.46 cm), number of seeds pod-1 (9.68), 1000-grain weight (35.13 g) and seed yield (807.31 kg ha-1) were recorded from 35 kg seed ha-1.similar results were also found in 40 kg seed ha-1.these results are in contrast with taj et al. (2003) who found that the number of seeds pod-1 and 1000-seed weight decreased with increasing seed rate. the highest stover yield was obtained from 40 kg seed ha-1 that might be due to highest plant population at 40 kg seed ha-1. however, the maximum seed yield was obtained from 35 kg seed ha-1 (807.31 kg ha1) which was closely followed by 40 kg seed ha-1 (806.52 kg ha1). jahan and hamid (2004) a) b) 84 rahman et al. also reported that significant variation in number of pods palnt-1 and seeds pod-1 due to difference in population density caused the variation in seed yield. fig. 2. interaction effect of variety and seed rate on plant population at 20 das mungbean under strip tillage system table 2. effect of variety on yield and yield contributing characters of mungbean under strip tillage system variety number of pods plant-1 pod length (cm) number of seeds pod1 1000seed wt. (g) seed yield (kg ha-1) stover yield (kg ha-1) barimung-6 34.53 b 7.96 b 9.68 a 37.14 a 506.56 b 1026.00 b bina mung-5 40.73 a 8.08 a 9.61 a 32.20 b 888.17 a 1874.25 a bina mung-8 35.20 b 7.75 c 7.716 b 31.02 c 429.80 c 890.55 c lsd(0.05 ) 2.63 0.11 0.34 1.88 15.77 30.60 cv (%) 2.96 1.58 3.03 1.78 4.87 3.18 in a column figures with same letters do not differ significantly whereas figures with dissimilar letters differ significantly (as per dmrt). in case of interaction effect of variety and seed rate, number of pods plant-1, pod length, number seeds pod-1, seed yield and stover yield of mungbean were also significantly varied with treatments except 1000-grain weight (table 4). the highest number of pods plant-1 (44.0) was counted from bina mung-5 at 20 kg ha-1 but, the highest pod length (8.79 cm) with higher number of seeds pod-1 were obtained from bina mung-5 sowing at 35 kg seed ha-1 resulting the highest seed yield (1215.35 kg ha-1). while the highest stover yield (2506.12 kg ha-1) was found from bina mung-5 at 40 kg seed ha-1 because of having the highest number of plant population. in case of bari mung-6, 35 kg seed ha-1 also produced higher seed yield compare to other seed rates because of producing the highest number of seeds pod-1 (10.8). therefore, the results showed that bari mung-6, bina mung-5 and bina mung-8 gave their highest seed yield at 35 kg seed ha-1 but all varieties produced highest stover yield at 40 kg seed ha-1. singh et al. (2003), hasan (2004) and chowdhury (1999) also reported that seed yield of mungbean increased with increasing seed rate up to certain levels and thereafter decreased. on the other hand, all varieties gave the lowest yield (seed and stover) at 20 kg seed ha-1 and resulted less number of plant populations as a result the less number of seeds were produced per pods with the short pod length. 85 effect of variety and seed rate on yield performance of mungbean under strip tillage system table 3. effect of seed rate on yield and yield contributing characters of mungbean under strip tillage system seed rate (kg ha-1) number of pods plant-1 pod length (cm) number of seeds pod-1 1000seed wt. (g) seed yield (kg ha-1) stover yield (kg ha1) 20 40.33 a 7.35 e 7.72 d 31.72 b 316.90 d 807.00 e 25 38.22 ab 7.66 d 8.60 c 32.7 ab 501.90 c 1094.16 d 30 37.00 ab 7.86 c 8.82 bc 33.62 ab 608.12 b 1225.07 c 35 35.56 bc 8.46 a 9.68 a 35.13 a 807.31 a 1440.00 b 40 33.00 c 8.31 b 9.25 ab 34.13 ab 806.52 a 1751.00 a lsd(0.05 ) 3.39 0.14 0.44 2.43 20.36 39.51 cv (%) 2.96 1.58 3.03 1.78 4.87 3.18 in a column figures with same letters do not differ significantly whereas figures with dissimilar letters differ significantly (as per dmrt). conclusion the study results expressed that among the three mungbean varieties, the performance of bina mung-5 was superior as it produced the highest seed yield at 35 kg seed ha-1. in case of bari mung-6 and bina mung-8, 35 kg seed ha-1 also helped to obtain their maximum seed yield. the study also expressed that seeding rate more than 35 kg ha-1 increased stover yield but decreased seed yield where bina mung-8 at 20 kg seed ha-1 produced the lowest seed and stover yield in this system. table 4. interaction effect of variety and seed rate on yield and yield contributing characters of mungbean under strip tillage system variety × seed rate (kg ha-1) number of pods plant-1 pod length (cm) number of seeds pod-1 1000-seed wt. (g) seed yield (kg ha-1) stover yield (kg ha-1) 20 38.3 de 7.52 g 8.2 de 35.16 191.15 k 430.47 k 25 35.7 fg 7.75 fg 9.5 c 36.14 389.74 i 854.80 h 30 34.0 gh 8.00 de 9.8 bc 37.47 521.70 g 1072.34 g 35 33.7 h 8.33 b 10.8 a 39.19 730.12 e 1324.17 f bari mung-6 40 31.0 j 8.19 bcd 10.1 b 37.74 700.30 e 1449.34 e 20 44.0 a 7.28 h 8.7 d 30.56 460.63 h 1307.05 f 25 42.3 ab 7.70 g 9.5 c 31.14 787.08 d 1663.49 d 30 41.3bc 7.94 ef 9.7 bc 32.16 876.30 c 1769.87 c 35 39.7 cd 8.79 a 10.2 b 34.00 1215.35 a 2124.21 b bina mung-5 40 36.3 f 8.69 a 10.0 b 33.15 1102.41 b 2506.12 a 20 38.7 d 7.26 h 6.3 h 29.44 299.20 j 683.70 j 25 36.7 ef 7.53 g 6.8 g 30.73 329.10 j 765.10 i 30 35.7 fg 7.64 g 7.0 g 31.24 426.43 hi 832.95 h 35 33.3 hi 8.26 bc 7.6 f 32.19 619.36 f 873.30 h bina mung-8 40 31.7 ij 8.04 cde 8.1 e 31.50 475.07 gh 1297.48 f lsd (0.050 1.84 0.21 0.45 1.00 49.95 67.68 cv (%) 2.96 1.58 3.03 1.78 4.87 3.18 in a column figures with same letters do not differ significantly (as per dmrt). references bbs. 2016. statistical year book bangladesh 2014. p: 113. 86 rahman et al. bonari, e., and m. macchia. 1975. effect of plant density on yield of bean (vicia faba) minor, spacing back. indian j. plant physiol. 204: 119-121. chowdury, a. s. 1999. effect of seed rate and weeding regime on the yield and yield contributing characters of summer mungbean. ms thesis, dept. of agron., bau, mymensingh. p: 38. dainavizadeh, p. and m. mehranzadeh. 2013. effect of seed rate on growth, yield components and yield of mungbean growth under irrigated conditions in the north of khuzestan. int. j. agric. crop sci. 5(20): 2359-2364. endres, g. and p. hendrickson. 2010. row crop performance with tillage systems and placement of fertilizer. in: carrington research extension center annual report. vol. 15.v hasan, s. m. m. 2004. effect of seed rate on the yield and quality of mungbean. ms thesis, dept. of agron., bau, mymensingh. p: 39. jahan, m. s. and a. hamid. 2004. effect of population density and planting configuration on dry matter allocation and yield of mungbean (vigna radiate (l.) wilczek). pakistan j. biol. sci. 7(9): 1493-1498. mackenzie, d. r. and t. d. lious. 1985. response of mungbean and soybean (glycine max l mirr) to increasing plant density. am. society hort. sci. 100: 579-583. moa (ministry of agriculture). 2012. hand book of agricultural statistics. ministry of agriculture, government of people’s republic bangladesh, dhaka. p. 27. nowatzki, j., g. endres, j. dejong-hughes and d. aakre. 2011. strip till for field crop protection. available at: www.ag.ndsu.edu shanmugasundaram, s., j. d. h. keatinge and j. hughes. 2009. counting on beans: mungbean improvement in asia. in: spielman d. j., and r. pandya-lorch (eds.) millions fed: proven successes in agricultural development, ifpri, washington dc. singh, g., h. s. sekhon, j. s. sandhu, s. j. singh, r. k. gumber and a. s. randhawa. 2003. effect of location and seed rate on three genotypes of mungbean. trop sci 43: 116-120. taj, f. h., m. arif and k. m. kakar. 2003. effect of seed rates on mungbean varieties under dryland conditions. int. j. agric. biol. 5(1): 160-161. undp and fao. 1988. agro-ecological region of bangladesh. land resources appraisal of bangladesh for agricultural development. united nations development programme and food and agricultural organization. bgd/81/035, tech. rep. n2, fao and undp. pp: 212-221. intercropping different vegetables and spices with pointed gourd bangladesh agron. j. 2015, 18(1): 7-12 efficiency of intercropping vegetables and spices relayed with pointed gourd m. r. islam1, m. a. k. mian2, s. n. mahfuza3, j. hossain4 and a. hannan5 1senior scientific officer, agronomy division, rars, bari, ishurdi, pabna, bangladesh 2principle scientific officer, regional agricultural research station ishurdi, pabna, bangladesh 3scientific officer, agronomy division, bari, joydebpur, gazipur 4scientific officer, agronomy division, regional agricultural research station ishurdi, pabna, bangladesh 5senior scientific officer, bari, joydebpur, gazipur, bangladesh key words: intercropping, relay, vegetables, spices, pointed gourd abstract an intercropping experiment was conducted at the regional agricultural research station, bari, ishurdi, pabna during 2007-2008 and 2008-2009 to find out the suitable intercrop combination for increasing total productivity and returns. seven treatments, viz. sole pointed gourd, two times lalshak + two rows turmeric in between pointed gourd lines, two times spinach + two rows turmeric in between pointed gourd lines, one time bushbean + two rows turmeric in between pointed gourd lines, two times lalshak + two rows ginger in between pointed gourd lines, two times spinach + two rows ginger in between pointed gourd lines and one time bushbean + two rows ginger in between pointed gourd lines were compared. all the intercropping combinations were higher in terms of pointed gourd equivalent yield, gross return, gross margin and benefit cost ratio (bcr) over sole crops. the highest pointed gourd equivalent yield (105.92 t ha-1) and gross return (tk. 2118480 ha-1) was found from two times spinach + two rows ginger in between pointed gourd lines combination. the land equivalent ratio was observed highest (2.29) in same combination which was similar to one time bushbean + two rows ginger in between pointed gourd lines combination. one time bushbean + two rows ginger in between pointed gourd lines combination gave the highest monetary returns in respect of gross margin (tk.1623333 ha-1) and bcr (4.19). the increases in total productivity in terms of pointed gourd equivalent yields were 53.72-128.62 t ha-1 in intercrop combination compared to base crop. introduction intercropping is a system that might be increase total production and profitability per unit area per time per inputs without affecting the production of the sole crops (islam et al., 2013). pointed gourd (trichosanthes dioica) is an important vegetables crop of bangladesh. it is cultivated round the years in about 10020 hectares of land throughout the country (bbs, 2011). adoption of pointed gourd by cultivators poses a threat to some traditionally grown crops like turmeric, ginger and some extent leafy vegetable, bushbean etc. due to its high market value. pointed gourd is a long duration (8-10 month) wide spaced crop with slow growth in early stages. so, there is a scope to grow the high values vegetables (red amaranth, spinach, bushbean) as intercrop at early growth stage and relayed a shade loving crop like turmeric and ginger without hampered pointed gourd production. vegetables and spices may be grown as intercrop and relay crop with pointed gourd as they have different growth habit, growth duration and demand for growth resources. turmeric and ginger can be cultivated in 8 islam et al. shady places as they are shade loving crop (haque and hossain, 1985; joyachandran et al., 1991). as such the experiment was therefore, undertaken to find out the suitable intercrop combination for increasing total productivity and returns with short duration vegetables crop with pointed gourd. materials and methods the experiment was conducted at the regional agricultural research station, bari, ishurdi, pabna during 2007-2008 and 2008-2009 to find out the suitable intercrop combination for increasing total productivity and return. the treatments were t1= sole pointed gourd, t2= two times lalshak + two rows turmeric in between pointed gourd lines, t3= two times spinach + two rows turmeric in between pointed gourd lines, t4= one time bushbean + two rows turmeric in between pointed gourd lines, t5= two times lalshak + two rows ginger in between pointed gourd lines, t6= two times spinach + two rows ginger in between pointed gourd lines and t7= one time bushbean + two rows ginger in between pointed gourd lines. the experiment was conducted in a randomized block design with three replicatons. the unit plot size was 6.0 m 1.25 m. pointed gourd spacing was maintained as 1m 1m. pointed gourd, lalsak (red amaranth), spinach and bushbean were planted / sown on 2 and 7 december 2007 and 2008, respectively. lalshak and spinach were sown for second time after harvesting of first sowing. turmeric and ginger were relayed in between two pointed gourd lines on 16 and 28 march 2008 and 2009, respectively after harvesting of vegetables (second time) and bushbean maintaining 50 cm 25 cm spacing. pointed gourd was harvested from 1st may, 2008 to 30 october, 2008 and 5 may 2009 to 28 october 2009 respectively. lalshak (red amaranth) and spinach were harvested on 26-28 das and 35-40 das respectively, in both sowing times. turmeric and ginger was harvested on 7 and 10 december 2008 and 2009, respectively. the seed rate of lalshak (red amaranth), spinach, bushbean, turmeric and ginger were 2, 20, 120, 2000 kg ha-1, respectively. pointed gourd var. bari potol-1, red amaranth var. bari lalshak1, local var. of spinach, turmeric var. shinduri and local var. of ginger were used in the experiment. trelly size was 6.0 m x 1.30 m (12 plants / trelly). during pointed gourd planting, 4.0 kg cowdung and 50 g tsp were applied in each pit. urea and muriate of potash were applied at the rate of 25 g in each pit with three equal installments at 20, 60 and 90 dae. lalshak was fertilized @ 108-24-40-6 kg ha-1 of n-p-k-s, respectively. half of n and full amount of other nutrients were applied as basal dose and rest n was applied at 20 das. second sown lalshak was fertilized with 54 kg ha-1 of n as basal and 54 kg ha-1 as top dressed at 20 das. spinach was fertilized with 10 t ha-1 of cd + 92-15-38 kg ha-1 of n-p-k. half n and full amount of other nutrients were incorporated as basal. rest n was top dressed at 15 das. second sown spinach was fertilized with 46 kg ha-1 of n as basal and 46 kg ha-1 was top dressed at 15 das. bushbean was fertilized with 120-40-60-12-3 kg ha-1 of n-p-k-s-zn. half n and full amount of other nutrient was given as basal and rest n was top dressed at 30 das. for ginger, 160-60-160-20-4 kg ha-1 of n-p-k-s-zn and for turmeric, 160-48-140-20-4 kg ha-1 of n-p-k-s-zn was applied. half n and full amount of other nutrients were incorporated as basal both for ginger and turmeric. rest n for ginger was top dressed at 42 das and for turmeric at 80 das. plots were kept weed free for whole growing period. irrigation and other intercultural operation were done as and when required. data on yield and yield attributes were taken and analyzed statistically. equivalent yield, gross return, gross margin and bcr were calculated. pointed gourd equivalent yield (pey) was calculated as follows: 9 efficiency of intercropping vegetables and spices relayed with pointed gourd pey = yield of intercrop pointed gourd + gourd pointedof price pi yi yi = intercropsof yield (vegetables/spices) pi = intercropof price (vegetables/spices) land equivalent ratio (ler) values were determined from the yield data of the crops according to mian (2008). ler = ryp + ryi = p p sy iy sy eycc p p where, ryp= relative yield of pointed gourd (main crop) ryi= relative yield of intercrops (vegetables and spices) piy = intercrop yield of pointed gourd psy = sole crop yield of pointed gourd peycc = pointed gourd equivalent yield of component crops {(component crop yield in intercrop × price of component crop)/price of pointed gourd}. results and discussion yield and yield contributing characters of pointed gourd there was no significant difference in yield and yield attributes of pointed gourd due to intercropping of vegetables/spices (table 1). the number of fruits plant-1 was statistically similar in different treatment combinations and it ranged from 79.70 to 91.00. the maximum number of fruits plant-1 was obtained in sole pointed gourd (91.00) while number of fruits plant-1 was recorded in two times spinach + two rows turmeric in between pointed gourd lines . the maximum fruit weight plant-1 was recorded in sole pointed gourd but it did not vary significantly due to intercropping. fruit weight ranged from 3.37 to 4.11 kg plant-1 in different treatment combinations. the maximum fruit yield (46.33 t ha-1) was obtained from sole pointed gourd which was at par with other intercropped combinations. among the intercropped combinations, the highest pointed gourd yield (45.08 t ha-1) was recorded in two times lalshak + two rows turmeric in between pointed gourd lines intercropped combination. the lowest pointed gourd yield (43.18 t ha-1) was found in two times spinach + two rows turmeric in between pointed gourd lines combination. table 1. yield contributing characters and yield of pointed gourd (pooled of 2007-08 and 2008-09) treatments fruits plant-1 (no.) fruit weight plant-1 (kg) fruit yield (t ha-1) t1 91.00 4.11 46.33 t2 83.51 3.74 45.08 t3 79.70 3.45 43.18 t4 84.70 3.87 43.31 t5 83.45 3.66 44.84 t6 79.76 3.47 44.67 t7 83.83 3.37 44.10 lsd(0.05) ns ns ns cv(%) 8.93 11.97 5.19 cv =coefficient variance, lsd=least significant difference, ns = not significant 10 islam et al. component crop yield on an average of two years result showed that the yield of lalshak (red amaranth), spinach, bushbean, turmeric and ginger under intercrops were ranged 11.76-12.10, 11.59-11.74, 9.38-10.05, 21.09-22.85 and 16.81-18.07 t ha-1, respectively (table 2). it was revealed that, among the vegetables, lalshak (red amatanth) showed higher yield (11.76-12.10 t ha-1) in intercropping system followed by spinach (11.59-11.74 t ha-1). similarly, between the spices crops turmeric showed higher yield (21.09-22.85 t ha-1) than ginger (16.81-18.07 t ha-1) in intercropping. joyachandran et al. (1991) reported from india that higher fresh ginger and turmeric yield was obtained in intercropping situation than sole crop due to shady condition than those in open sunlight. the result was in agreement with the findings of bendall and duly (1988). similar findings were also observed in the experiment where ginger / turmeric yield was found higher in intercropping combination just because ginger / turmeric was grown under partial supports (paulose, 1973 and ahmed et al. 1998). table 2. yield of component crops with pointed gourd under intercropping vegetables and spices relayed with pointed gourd inter cropping system (pooled of 2007-08 and 2008-09) treatments lalshak (two times) (t ha-1) spinach (two times) (t ha-1) bushbean (t ha-1) turmeric (t ha-1) ginger (t ha-1) t1 t2 12.10 21.13 t3 11.59 21.09 t4 10.05 22.85 t5 11.76 16.81 t6 11.74 18.07 t7 9.38 17.47 t1= sole pointed gourd, t2= two times lalshak + two rows turmeric in between pointed gourd lines, t3= two times spinach + two rows turmeric in between pointed gourd lines, t4= one time bushbean + two rows turmeric in between pointed gourd lines, t5= two times lalshak + two rows ginger in between pointed gourd lines, t6= two times spinach + two rows ginger in between pointed gourd lines, t7= one time bushbean + two rows ginger in between pointed gourd lines pointed gourd equivalent yield (pey) the produced all the component crops were converted into pointed gourd equivalent yield on the basis of existing market price for determine comparative efficiency of different treatment combinations. pointed gourd equivalent yield was referred to total productivity. pointed gourd equivalent yields were higher in all the intercrops (71.22-105.92 t ha-1) than the sole crop of pointed gourd (46.33 t ha-1) (table 3). the maximum pointed gourd equivalent yield (105.92 t ha-1) was recorded in two times spinach + two rows ginger in between pointed gourd lines combination which was followed by one time bushbean + two rows ginger in between pointed gourd lines combination (105.89 t ha-1).the total productivity increase of 53.72-128.62 percent over sole pointed gourd where two times spinach + two rows ginger in between the pointed gourd lines combination increased the highest total productivity (128.62%). 11 efficiency of intercropping vegetables and spices relayed with pointed gourd land equivalent ratio (ler) the land equivalent ratio (ler) in all the intercropping system was efficient having ler values more than 1.0 (table 3). ler of different crop combination ranged from 1.54 to 2.29 indicating 54-129% yield advantage by intercropping. the maximum ler value (2.29) was found from two times spinach + two rows ginger and one time bushbean + two rows ginger in between two rows of pointed gourd combination. table 3. pointed gourd equivalent yield (pey) and land equivalent ratio (ler) under intercropping vegetables and spices relayed with pointed gourd cropping system (pooled of 2007-08 and 2008-09) treatments pey (t ha-1) ler % increase of total productivity t1 46.33 1.00 t2 73.47 1.59 58.57 t3 71.22 1.54 53.72 t4 76.21 1.64 64.49 t5 102.33 2.21 120.87 t6 105.92 2.29 128.62 t7 105.89 2.29 128.55 economics intercrop combination had showed higher economic return than sole crop (table 4). the highest gross return (tk. 2118480 ha-1) was found from two times spinach + two rows ginger in between pointed gourd lines combination. one time bushbean + two rows ginger in between pointed gourd lines combinations gave the highest gross margin (tk. 1623333 ha-1) and bcr (4.19) followed by two times spinach + two rows ginger in between pointed gourd lines combination. among the intercrops, the lowest gross return (tk.1424480 ha-1), gross margin (tk. 994990 ha-1) and bcr (3.32) were obtained from two times spinach + two rows turmeric in between pointed gourd lines combination. sole crop of pointed gourd gave the lowest gross return (tk. 926600 ha-1), gross margin (tk. 597454 ha-1) and bcr (2.82). the results indicated that intercropping was highly productive and profitable as compared to sole stand. table 4. economics of intercropping vegetables and spices relayed with pointed gourd cropping system (pooled of 2007-08 and 2008-09) treatments gross return (tk.ha-1) total cost (tk.ha-1) gross margin (tk.ha-1) bcr t1 926600 329146 597454 2.82 t2 1469400 418878 1050522 3.51 t3 1424480 429490 994990 3.32 t4 1524200 398846 1125354 3.70 t5 2046520 514499 1532021 3.98 t6 2118480 525111 1593369 4.03 t7 2117800 494467 1623333 4.19 market price: pointed gourd: tk.20.00 kg-1, lalshak: tk.12.00 kg-1, spinach: tk.12.00 kg-1, bushbean: tk.15.00 kg-1, turmeric: tk.20.00 kg-1, ginger: tk.60.00 kg-1 12 islam et al. conclusion the result revealed that the maximum monetary returns in respect of gross margin (tk. 1623333 ha-1) and bcr (4.19) could be obtained with one time bushbean + two rows ginger in between pointed gourd lines combinations. therefore, farmers should be interested to grow pointed gourd at wider spacing (1m x 1m) intercropped with vegetables and relayed of spices instead of monoculture of pointed gourd. references ahmed, n. u., m. m. rahman, m. m. hoque and a. k. m. amzad hossain. 1998. effect of seed size and spacing on the yield of ginger. bangladesh hort. 16(2): 50-52. bangladesh bureau of statistics (bbs). 2011. statistical year book of bangladesh. statistics division, ministry of planning, government of the peoples republic of bangladesh, dhaka. bendall, r. l. and r. a. duly. 1988. ginger growing in the nambour area, queens land, quarterly rev. agril. econ. 19: 86-96. haque, m. m. and s. m. m. hossain. 1985. spice and root crops in the context of homestead garden in bangladesh. workshop proceedings, present status and future prospects of research on root and spice crops. barc, p 51. islam, m. r., m. a. k. main, n. ara and m. f. hossain. 2013. intercropping lentil and turmeric relayed with pointed gourd. bangladesh j. agric. environ. 9(1): 33-37. joyachandran, b. k., m. m. bai, m. a. salam, m. k. mannan and k. p. mathew. 1991. performance of ginger under shade and open condition. indian coca, arecanut and spices j. (2): 40-42. mian, m. a. k. 2008. performance of maize oriented cropping patterns under different nutrient management. ph. d. dissertation. dept. agron. bangladesh agril. univ., mymensingh. pp. 31-137. paulose, t. t. 1973. ginger cultivation in india, proceedings of the conference on spice 10-14 april, 1972. tropical products institute, london. microsoft word final.doc � �������� ��� �������������������������� ���� �!"#�$#����"%�&���� �!"#�$#����"%�&���� �!"#�$#����"%�&���� �!"#�$#����"%�&�' �$�!���(�'��#��)��' �$�!���(�'��#��)��' �$�!���(�'��#��)��' �$�!���(�'��#��)��#�(�'�� ��#�(�'�� ��#�(�'�� ��#�(�'�� � *�'(�)#�$&� �#�)*�'(�)#�$&� �#�)*�'(�)#�$&� �#�)*�'(�)#�$&� �#�)���� ���� )��'��*�+,�)��'��*�+,�)��'��*�+,�)��'��*�+,�������$���-.� ��$���-.� ��$���-.� ��$���-.� ������/�����*��0 ����/�����*��0 ����/�����*��0 ����/�����*��0 ��1111����0��0�23 0��0�23 0��0�23 0��0�23 ������/���/���/���/�����/��� ��4/��� ��4/��� ��4/��� ��45555���� ��1�6�5)73��.3837�"8837� ���� 37,�., ���'� �� 7 �).�.3������'���9�43���� �/�)� .,���.�������2��� ,�) �3�/�:32, �'� 4����� 37,�., ���;�3<� 3.=� �� 3 .��.�! �8� � �� �>� .4��.��8�*� .37,�., ���) � ������������� 37,�., ���;�3<� 3.=� 9� � >���3����,. � ���=,2�� ���4=?=� ���7�4� 0�=�@� � ��0�=�@� � ��0�=�@� � ��0�=�@� � ��&� ����>���� � <� .3���.34���<� 3�.=� ���� �2 . �7.�2 . �7.�2 . �7.�2 . �7.���� ���� ��83�����a>� 34��.�@� �7� 3����,.��.� . ���a>� 34��.��� 83�����8� �>� .4��.��8�&���.37 � ���� !���.� � ���3��� �8� �����2��� ,� ) �3� /,:32, � '� 4��� �� 37,�., ��� ;�3<� 3.=�� )������&�b3>, ��, 3���$�<�42� ������. �,� ��> 3�����c�.��83����,.�. ��>� 8� 4��7�� �8� �388� ��.� >��� <� 3�.3� � �.� �388� ��.� � <� .3��� .34��� # �� . ��.4��. � 7�� 3 .��� �8� .@�� 8�7.� ��@ 37 �@� ��8�, � � <� .3���.34� ����������c������������= ��8.� � �@3�������� 3a� <� 3�.3� � �8� �� ����>��� ��!)��/�.� � ,.3���� �!)��/�.� � ,.3���� �!)��/�.� � ,.3�1�� ��'��/�.� � ,.3������'��/�.� � ,.3�1�������7���@ 3.����# ���a>� 34��.�@� ���3���,.� 3���� ����43b���7�4>��.��2��7-��� 3���@3. �. ��� �>�37�.3�� ��# ��4�a34,4�>���=3���� �������.� �����@� ��2.�3����8 �4���'��/�.� � ,.3��� � <� .3����.������= ��8.� � �@3��� @ 37 �@� � .�.3 .37���=� 343�� �.���!)��/�.� � ,.3���� � <� .3����.������= ��8.� � �@3��� ���� ��7��� @ 3.�� �.� �4�� � <� .3��� ��.�� ���� ,>� 3� � .�� . �� � .� �8� . �� . ��.4��.� 7�423��.3����# �� ��@� .� >��� =3���� �5��5� .� �����@� � > ��,7��� 2=���'��/�.� � ,.3��� � <� .3����.������= ��8.� � �@3������� ���� ��. ��,7.3����. ��,7.3����. ��,7.3����. ��,7.3������ ���� !��� �!3 ,4� �.3<,4� >�� *� .�� ��� 3 � @������� -��@����� � � �� <���.�2��� ���� ���� �8� . �� 34>� .��.� ���,4� � 3���������� �� �.� 3 � ��� ���,��� � 2�7��, � >���.� �8� 8�43�=� ���,43�� ��� �<3��� ���, � !3 ,4� ���� 4� .�=� � �@�� 8� � � ���� >�� � ���� ��� �� # �� ���, � 3�7�,�� � d��� >�73� �� # �� /��3.� ������ ��3����@� .� ������7��. ���� 3�������. 3�>3�� �<��2���� 3��37�.���� �7��.� ��8� 3. � � 3�3��� %� � �� ���3���>, >� � �� >�� �4�=�2�� 7�� 383��� � � �� ����>�� � �����3 �>�� ��� ��>� >�� � ���� ��@� >�� � � ,�� � >�� ��� &� ���� >��� <� 3�.3� � �<�� 4��. � � � @ 3�-���� ��� �� # �� � ����>�� �����344�., �� ��� �� �� 37 �3��<3.�43������ �<����2����7����43����73��7�4>� 3.3���� /� ��<� �� �4�� 34>� .��.� 43�� �� � ,7 � � � 7��73,4�� > � > � , � ���� 3 ��� � �� > � ��.� 3�� �2,����.�+,��.3.3� �3��>�� �@ 37 �� ����7-3���3��7� ��� ��# ��7 �>�2�7�4� �>�>,�� �8� �3. � 3� � �,. 3.3<�� <��,����������� .� .��� �.� 7��.�3� ��5�15e�> �.�3�������5e� .� 7 ������e� ,�� ����d� ��5e�8�.��������e�43�� �� ��/�-� �<����c�1���# ��34>� .��7���8�>���� ���<���.�2���7 �>� � � � >�=� 3�7 �� ��� 3�� 4��=� 7�,�. 3� � �8� . �� @� ���� �.� ��� . 3 �� � � 8�, . � 3�� . �� @� ��@3��� > ��,7.3��� �4���� . �� � �3�� ���,4� � �%� 3��.���� �c����� # �� 4�:� � � ���� >��� > ��,73��� 7�,�. 3� � �8� . �� @� ��� � �� ���3��� 9 3���� ;)��� % ��7��� ;0�� ��=>.�� *,��� =�� �.��=�� !�-3 .���� ��>�������# �3������ ����������� ��.�> � ��.�>��� 3 �� �@��3����<� =� 4����� ����8�������� �� �������,���> ��,7.3��� 3 � �2�,.�c�����4�. 37� .�� � ���)�����5���# ���<� ����� =� ����=3���� 3 � ���=����5�.� ����@ 37 �3 �4,7 ���@� �� �7�4>� ���.���. � �>���� �@3���7�,�. 3� � ,7 �� �;)�� 1�c��.� ���� ���������cc�������% ��7��1��1�.� ���� �/�-� �<����c�1���# �� ��@�=3���� 3 �4�3��=� �,�� .�� . �� , �� �8� ��@� =3���3��� 7,�.3<� � ���� ��7-� �8� ����� +,��3.=� ��� � ���� 7,�., ��� > �7.37� �� *� <� .3���.34����.� 43�� �. ���,. 3��.�7��.��. ����� ��8��38��3�� ��� ��8�>����*� <� .3���.34��3 � ��� *�+,���.����� -��@�� .�� �88�7.� ���� � �@. � ���� ��<���>4��.� � � 3.� > �<�3� � ,��� � �388� ��.� 7���3.3�� � 3�� . �� > �7� ��8� ������<���>4��.�� ����������� � <���.�2���>��� 3 �� �@���, 3���7���� >� 3��� 3�� . �� @3�.� � �� ��� �<3��� <� =� � .� �, �23�3.=�� # , � .34�� �8� � <� .3��� 3 � �� <� =� 34>� .��.� 8�7.� � @ 37 � 3�8�,��7� �=3���� � ��.�=��*� <� .3����8�>�� �2�=����� �2�8� �� 3. ��>.34,4�>� 3���7�, � � ��,7.3���3��+,��3.=� ����=3�����$�@�����=�. ���<� ����> ��,7.3����8�83����>���3���������� � � � 2���� � � .37���=� ��,7��� �,�� .�� 3�. ��,7.3��� �8� *�(� '37�� ���� @ ��.�� # , � . �� 7�>�� �8� 3. � > ��,7.3���� �83����7 �>� � ��� ���=�2�����343.����"��. ���. � � ����. � ��3 ��� � .�����8��88� �� ��� <���.�2��� 3�� �, � 7�,�. =�� & ���� >��� 7��� 2�� 7�� 3�� ��� � � <���.�2��� 7 �>� � � 3.� ����� 4���� �� �� ��8����������7����� ��2��� �@��@3. �,.�7�4>�.3.3���@3. �7� ����7 �> ��;��� �8 �b��� 7���3.3���. ��<���.�2���7���2��, ���. �,� �,.�. ��=�� ��*�@�<� ��3.�3 ���7� � =�.����.� 43��� . �� �>> �> 3�.�� � <� .3��� .34�� .�� �� , �� ���� +,��3.=� ����4�a34,4� > ��,7.3<3.=�� *��7�� . �� > � ��.� .,�=�@� �,��� .�-���.���<��,�.��. ��>� 8� 4��7���8��388� ��.�>���<� 3�.3� � � <� .����.� �388� ��.��.34� ������ ���� /�.� 3�� �����/�. /�.� 3�� �����/�. /�.� 3�� �����/�. /�.� 3�� �����/�. �� �� �� �� ���� ���� ��83�����a>� 34��.�@� �7� 3����,.��.�. ���a>� 34��.�83�����8� �>� .4��.��8�&���.37 �����!���.� � ���3����8������2��� ,�) �3�/,:32, �'� 4����� 37,�., ���;�3<� 3.=��)������&�b3>, ��, 3��� $�<�42� ������.���> 3�����c��# ���a>� 34��.�@� ���3���,.�3����'����43b���9�4>��.�����7-� � 3��� �'9� �� �<3��� .@�� 8�7.� � @3. � . ��� �>�37�.3�� �� # �� ,�3.� >��.� 3b�� @� � �4� a� �4� 4�3�.�3�3����3���.���3���1��74�����>���.�.��>���.����74��# ���a>� 34��.���2��7�@� �� �>� �.��� 2=���d�4��# ��>��. �@� �� �3 ���2=����74�8� �> �>� �3 3��.3����# ��. ��.4��. �3�7�,���%�7.� ���� *� <� .3���.34�f�*�g1�. ����,� =h��c����� �= ��8.� �)�@3�����*�g�c. �%�2 ,� =h�c����� �)��� *1g�c. �%�2 ,� =h�c��c�� �)���*�g� .�/� 7 h�c������ �)������%�7.� ����(� 3�.=f�(�g��!)�� /�.� � ,.3����(�g��!)��/�.� � ,.3����(1g��!)��/�.� � ,.3�1��(�g���'��/�.� � ,.3����(5g� ��'�� /�.� � ,.3�1�� (dg� ��7��� @ 3.��� # �� �a>� 34��.��� �3�� @� � @���� > �>� ��� 2=� ���>� >��,� 3���@3. � . �7.� � 8����@��� � �@3��� ���� ����� 3��� ,>� .�� �� ����� .3�. �� # �� �a>� 34��.��� >��. �@� ��,�38� 4�=�8� .3�3b���@3. �7�@��,����?��8����.� ������; ����?��8�����-�� ������#)!��?� �8��d��-�� ���������/�!��?��8�����-�� ������# ��.�.���7�@��,����#)!��/�!������i��, ���@� �� �>>�3����, 3���. ��83���������> �>� �.3�������. �� � .��8�. ��, ���@� ��.�>�� � ���3��. ��>��.�3�� .@��3� .���4��. ��# ��83 .�3� .���4��.�@� �.�>�� � ����.��������. �� �7����@� ��.������= ��8.� � �@3����)��� �@� �� �@��?���1� ��� � 3����� ���$�<�42� ���� 3�� 8, �@ �4�3�.�3�3��� . �� �@� >�73����8�1��74�����>���.�.��>���.� >�73������74��# 3��3���@� �������8.� ��������5���= ��8� �4� ���7�� 8� � -��>3��� �� 3 ��� >���.� ��� 3.=�� # ���@���3���@� �� ����� �8.� � �5�� 1�� ���� �5� ��= � �8� �4� ���7�� 2=� ���� .�� �<�3�� 7�4>�.3.3��� 2�.@���� . �� >���. � ���� @��� �� ! �>� � 3 3��.3���@� � ����� � � ����@ ���� #��� >���. �@� �� ����4�=� ���7.��� 8 �4� ��7 � >��.� 8� � ��.�� 7����7.3������=3����7 � �7.� 3 .37 �����>�� �@� ��7����7.��� 8 �4�. �� >�73837�>��.��.� . �� >�73837� � <� .3��� .34�� �77� �3��� .�� . �� . ��.4��.�� %� � ���� > ��,7.3���@ ���� >���. � @� �� � <� .��� 8 �4���7 �>��.� �77� �3��� .�� . �� . ��.4��.���8.� � � <� .3��� . ��>���� . �� ��� �@� �� �4�<��� ���� �>� �.���2=� ���������� ���� '� ,�. ����� 3 7, 3��'� ,�. ����� 3 7, 3��'� ,�. ����� 3 7, 3��'� ,�. ����� 3 7, 3������ ���� ��.� �7.3����88�7. ����=3��������=3����7��. 32,.3���7 � �7.� ��8��� ����>����.� �7.3����88�7. ����=3��������=3����7��. 32,.3���7 � �7.� ��8��� ����>����.� �7.3����88�7. ����=3��������=3����7��. 32,.3���7 � �7.� ��8��� ����>����.� �7.3����88�7. ����=3��������=3����7��. 32,.3���7 � �7.� ��8��� ����>������ �= �.��5�e�8��@� 3�� �= �.��5�e�8��@� 3�� �= �.��5�e�8��@� 3�� �= �.��5�e�8��@� 3���� # ��3�.� �7.3����8�<� 3�.=����� � <� .3���.34��� 3��3837��.�=�3�8�,��7���. ����= ��8�5�e�8��@� 3��� �8�. ��7 �>��#�2�������# ��. ��.4��. �*�(���*�(5��*�(���*�(5��*1(���*�(������*�(5� �@��� �1� �3�����8�&� ����!����.�(� 3���*� <� .3��� �.� ���� 5�e� 8��@� 3��� �.� 15� ��= � @ 37 � @� � . ��43�34,4� ���� 3.� @� � .�.3 .37���=� 3���.37��� .�� ���� . �� . ��.4��. ��a7�>.�*�(���*�(d��*�(���*�(d��*1(���*1(d��*�(������*�(d��(d�<� 3�.=�.��-�. �� ����� .� >� 3��� �d�� ��= �� @3. � . �� 7�423��.3��� �8� ���� . �� � <� .3��� .34��� (� 23. -33� ��cd��� �>� .��� . �.� . �� �, �.3��� �8� . �� >� 3��� 8 �4� �� 43��.3��� .�� 8��@� 3��� �8� . �� �4�� <� 3�.3� � <� 3���8 �4����.�������= �3���388� ��.�=�� ��� ���� $,42� ��8�2 ��7 � �>���.$,42� ��8�2 ��7 � �>���.$,42� ��8�2 ��7 � �>���.$,42� ��8�2 ��7 � �>���.������������ '�4� -�2��� <� 3�.3��� @� � 8�,��� 3�� . �� �,42� � �8� 2 ��7 � � >���.��� �4���� . �� . ��.4��. � 7�423��.3��� �8� � <� .3��� .34�� ���� <� 3�.3� � �#�2��� ���� /�a34,4� �,42� � �8� 2 ��7 � � ������ >���.���� @� � �7� ���� 3�� *�(1� @ 37 � @� � 3��3837��.�=� 3� � � . ��� �. � � 7�423��.3�� �� # �� ��@� .� �,42� � �8� 2 ��7 � � ������ >���.���� @� � �2.�3���� 8 �4� . �� . ��.4��.� *�(�� @ 37 � @� � .�.3 .37���=� 343�� �.��. ��.4��. �*�(������*�(������ ���� !���.� �3� !���.� �3� !���.� �3� !���.� �3� .��74�.��74�.��74�.��74����� !���.� �3� .� �8� �388� ��.� <� 3�.3� � �8� >��� @� � 3��3837��.�=� 3�.� �7.��� @3. � � <� .3��� .34�������� �#�2��� ���� # �� <� 3�.=� (1�@� � . �� .���� .� ��d�5�� 74� >���.���� �.� � <� .3��� .34��*1�@ 37 �@� � .�.3 .37���=� 343�� �.��*�(1��# �� � .� .�>���.��������74�>���.����@� �8�,���3��*�(������3.�@� � .�.3 .37���=� 343�� �.��*�(���*�(������*1(��� ���� #�2��� ��� ��.� �7.3��� �88�7.� �8� <� 3�.=� ���� � <� .3��� .34�� ��� ��= � .�� 5�e� 8��@� 3��������������� �,42� ��8�2 ��7 � �>� �>���.�����>���.� �3� .��8�>��� # ��.4��. � �= �.��5�e�8��@� 3��� $,42� ��8�2 ��7 � �>���.��� !���.� �3� .��74�� *�� (�� 15���7� ������ �����:� (�� �����7� ������ 1��c1 3� (1� 5����27� ��552� d����7� (�� dd����� ���58�� �d������� (5� 15���7� ��1�7��� �����8� � (d� d������ ��157�� 5���1��8� � *�� (�� 15���7� ������� ����1:� (�� �����7� ��1�7�� 1��c���3� (1� 5����27� ������ �����2� (�� dd����� ����7��� 51��57��� (5� 15���7� ����7� ���1c8�3� (d� d������ ��1c7�� 5c���7�� *1� � (�� 15���7� �����8� �����:� (�� �����7� ��1�7��� 1��55 3� (1� �c�1127� ��157�� �d�5��� (�� d�����2� ����7��� 55�d�7�� (5� 15�117� ��1d7�� 1������3� (d� d������ ��1�7�� 5c���7�� *�� � (�� 15���7� ��1�7�� �����:� (�� �����7� ����7��� 15�d�3� (1� 5����27� ����7� ���d��2� (�� dd����� ������� 51��17��� (5� 15���7� ��1�7��� 1��15 3� (d� d������ ��1�7��� 55�c17�� %�<��,�� ����jj� d�c�jj� ����jj� 9(��e�� �d��d� ���d� c���� *�g1�. ����,� =h�c����� �= ��8.� �)�@3�����*�g�c. �%�2 ,� =h�c����� �)���*1g�c. �%�2 ,� =h�c��c�� �)���*�g� .� /� 7 h�c������ �)���(�g�!)��/�.� � ,.3����(�g�!)��/�.� � ,.3����(1g�!)��/�.� � ,.3�1��(�g��'��/�.� � ,.3� ���(5g��'��/�.� � ,.3�1��(dg��7���@ 3.���� /��� �3����7��,4��8����@���2=� �4����..� � ��� ����.� 3��3837��.�=��388� ��.��.���e���<����8� 3��3837��7���� ��� *�+,���.����� !�������. ��44�>��!�������. ��44�>��!�������. ��44�>��!�������. ��44�>������������������ !��� ����. � �8� >��� <� 3�.3� � <� 3��� 3��3837��.�=� @3. � �388� ��.� � <� .3��� .34� � �#�2��� ���� # �� ����� .� >��� �d1�d�� 44� >������ @� � �2 � <��� 3�� . �� . ��.4��.�� *1(d�� @ 37 � @� � .�.3 .37���=� 3���.37��� .�� ���� . �� . ��.4��. � �a7�>.� *�(��� *�(d�� *1(��� *�(�� ���� *�(1�� # �� ��@� .� >��� ����. �����5��44�>������@� ��2 � <���@3. �. ��. ��.4��.��*�(���� ���� !���!���!���!���2 ���. ��44�>��2 ���. ��44�>��2 ���. ��44�>��2 ���. ��44�>������������������ # �� 3�.� �7.3��� �88�7.� �8� <� 3�.=� ���� � <� .3��� .34�����>��� 2 ���. �@� � 3��3837��.� �#�2������� # ��. ��.4��.��*�(��> ��,7���. ��@3�� .�>�����1��d�44�>������@ 37 �@� � .�.3 .37���=� 343�� � .������. ��. ��.4��. ��a7�>.�*�(���*�(d��*�(1��*�(���*�(d��*1(1��*1(���*1(d��*�(1��*�(�� ����*�(d�� # �� �� �@� .� >��� �c��1�44� >������ @� � �2.�3���� 2=� . ��.4��.�*�(1�@ 37 � @� � .�.3 .37���=� 343�� �.��. ��.4��. �*�(d��*�(1��*�(d�����*1(1�� � !���@�3� .����>��!���@�3� .����>��!���@�3� .����>��!���@�3� .����>������������������ # ��>���@�3� .���>�����<� 3���� ��.�=�8� ��388� ��.�<� 3�.3� ��8�>����.��388� ��.� � <� .3�����<�� � �#�2�������# ��4�a34,4�>���@�3� .�����1���>������@� �> ��,7���2=�. ��. ��.4��.��*�(5�@ 37 � @� � .�.3 .37���=� ,>� 3� �.��. ��. ��.4��. �*�(���*�(���*�(1��*�(���*�(5��*�(d��*�(���*�(��� *�(��� *�(1� ���� *�(��� # 3 � 43� .� 2�� �,�� .�� 7�423��.3��� *�(5� �7�3<��� 7�4>� �.3<��=� �>.34,4�.34��8� �> �>� �=�� �@3��������3����.�� 3����,.�<� =�4,7 ����<3 ��4��.���8�7.� �. �.� ,3.��� . �� ����.37� >�.��.3��� .�� 2�� �a>��3.��� 8� � >���@�3� .�� # ��@��. � � > �<�3���� �, 3��� . 3 � .34��@� �>� �> �8�<� �2���8� �. ��4�a34,4�<���.�.3<��� �@. ��8�>���.����������.��> ��,7.3��� �8� 3� � �> �.� =�. �.37�> ��,7. �@ 37 � � ,�.�3��4�a34,4�>������@�3� .��# ����@� .�>���@�3� .� ��������>������@� ��2.�3����2=�*�(1��8�. ��7 �>��# � ��83��3�� �� �� ,>>� .���2=�)�7 ����.����� ����1��� � $,42� ��8�>�� �>���.$,42� ��8�>�� �>���.$,42� ��8�>�� �>���.$,42� ��8�>�� �>���.������������ $,42� ��8�>�� �>���.��� 3 ��� ����� 34>� .��.� 8�7.� ��4���� . ��=3���� 7��. 32,.3���7 � �7.� ���� 3��3837��.� 3�.� �7.3����88�7.� 8� ��,42� ��8�>�� �>� �>���.�@� ��2 � <��� �#�2�������# �� 3� � .� �,42� � �8� >�� � �5���� >���.���� @� � > ��,7��� 2=� . �� . ��.4��.�� *�(�� @ 37 � @� � .�.3 .37���=� 343�� � .�� *�(1�� *�(��� *�(��� *�(1�� *�(d�� *1(��� *1(1� ���� *�(�� �8� >���� # �� 43�34,4� �,42� ��8�>�� ��1����>���>���.���� �@���2=�. ��.4��.�*�(��� � $,42� ��8� ��� �>��$,42� ��8� ��� �>��$,42� ��8� ��� �>��$,42� ��8� ��� �>�������������� ��.� �7.3����88�7.��8�<� 3�.=����� � <� .3���.34��>��=����� 3��3837��.� ��������,42� ��8� ��� �>��� ���8�>���.����#�2���1���# ��4�a34,4��,42� ��8� ��� �>������d�1���@� � �7� ����3��*�(��@ 37 � @� � .�.3 .37���=� 343�� �.��*�(���*�(���*�(1��*�(5��*�(d��*1(���*1(���*1(d��*�(������*�(d� . ��.4��. ��# ��43�34,4��,42� ��8� ��� � �1����>������ �7� �����.� . �� . ��.4��.�*�(���# �� 43�34,4��,42� ��8� ��� �>�����3��*�(��43� .�2���,��.��. ����7-��8�> �>� �.34��.��� �@����� ,�8�<� �2�����<3 ��4��.���7���3.3����� ���� !���=3�������>���.!���=3�������>���.!���=3�������>���.!���=3�������>���.���������������� !��� =3����>���.���@� � 3��3837��.�=� 3�8�,��7���2=� . �� 3�.� �7.3��� �88�7.� �8� <� 3�.=����� � <� .3��� .34�� �8� . �� 7 �>� �#�2��� 1��� # �� . ��.4��.��*�(�� > ��,7��� . ��4�a34,4�>��� =3���� ������� �� >���.����@� � .�.3 .37���=� ,>� 3� �.��. �� � .��8�. ��.4��. ��8�>����# 3 �43� .�2���,��.��>���. ��8� *�� � <� .3��� .34�� �7�3<��� 7�4>� �.3<��=� 8�<� �2��� ��<3 ��4��.� ���� �>.34,4� .34�� 8� � <���.�.3<��� �@. ��8�>���.�@ 37 ������.��8� 4�.3����8� 3� � �> �.� =�. �.37�> ��,7. � � ,�.���3�� �5� �3�����8�&� ����!����.�(� 3���*� <� .3��� �.� ���� 3� � �>���=3����>���.����# ����@� .�>���=3��������5����>������> ��,7���2=�. ��. ��.4��.��*�(��� # � ��83��3�� �� �� ,>>� .���2=�)�7 ����.���������1������9 ��� ������!��3 �..=���cc������� � #�2��� ��� ��.� �7.3��� �88�7.� �8� <� 3�.=� ���� � <� .3��� .34�� ��� >��� ����. �� >��� 2 ���. ����������������� >���=3���������,42� ��8�>�� ��8�>��� # ��.4��. � !�������. � �44�>������ !���2 ���. � �44�>������ !���@�3� .� ���>������ $,42� ��8� >�� �>���.��� *�� (�� ���5��� ��������� 1��c��8� 1�c17��� (�� 5��51���� ����1���� 1�112�8� ��1�2��� (1� ��������� ���d1���� 1��17�8� ��51���� (�� 5c������� ��������� 1��52�8� 1����� (5� 5c�1c��7� ��������� 1�����8� 1������ (d� �5��d2��� c����� � 1���7�8� 1�c17��� � *�� (�� 51������� ����c��7� 1��1���� ��5����� (�� 5���d���� ����5�2� 1��1��8� ������7� (1� 5�������� �����8� � 1�d1���� ��c1��7� (�� d���d�2� ���c�7��� ���5�2� 5����� (5� 5���d���� ����c��7� ���1�� ����7��� (d� 5���d���� ������� � 1������� 5��d�2� *1� � (�� �����7�� ������2� 1�d����� ��1c2��� (�� 5��d����� ���15��7� 1�����8� �������� (1� ���5����� c����� � 1�15��8� ��d����� (�� 5c�d���7� ����1���� 1�5����� ���52��� (5� 5c�cd��7� �������7� 1�d����� ���52��� (d� d1�d��� ���5�2�8� 1�d1���� ���d2��� *�� � (�� �1���7�� ���1���7� ��c��8� ����2��� (�� ��������� �1��d�� 1�����8� ��d����� (1� �1��57�� c��1 � ����8� ��1�2��� (�� 5d�5d���� ���552�8� 1�����8� 1�c17��� (5� 51��d���� ������2� 1�c1��7� ����7��� (d� ���15���� ���c17��� 1�15��8� 1�c57��� %�<��,�� ���5jj� ��d�jj� ���cj� ����j� 9(��e�� �d���� d�5�� ������ ������ *�g1�. ����,� =h�c����� �= ��8.� �)�@3�����*�g�c. �%�2 ,� =h�c����� �)���*1g�c. �%�2 ,� =h�c��c�� �)���*�g� .� /� 7 h�c� ����� �)��� (�g�!)�� /�.� � ,.3���� (�g�!)�� /�.� � ,.3���� (1g�!)�� /�.� � ,.3�1�� (�g��'�� /�.� ����� ,.3����(5g��'��/�.� � ,.3�1��(dg��7���@ 3.���� /��� �3����7��,4��8����@���2=� �4����..� � ��� ����.� 3��3837��.�=��388� ��.��.���� �5�e���<����8� 3��3837��7���� ���� !���=3�����.!���=3�����.!���=3�����.!���=3�����.���� � � � ����������������� # �� 3�.� �7.3��� �88�7.� �8� <� 3�.=� ���� � <� .3��� .34�� ��� >��� =3���� >� � �7.� �� @� � 3��3837��.� �#�2��� 1��� # ��4�a34,4� >��� =3���� ������� .� ����� @� � �2.�3���� 8 �4� . ��.4��.� *�(�� �8� >��� @ 37 �@� � .�.3 .37���=� 343�� � .��*�(������*�(d����� ,>� 3� � .�� . �� � .� �8� . �� . ��.4��. ��8� >���� # �� ��@� .� >��� =3���� �5��5� .� �����@� � > ��,7��� 2=� . ��.4��.�*�(���# � �� 83��3�� � � �� ,>>� .���2=�)�7 ����.���������1������9 ��� ������!��3 �..=���cc������� ���� )����=3����>��)����=3����>��)����=3����>��)����=3����>������������������������������ # � ��@� ��� 3��3837��.�3�.� �7.3����4����. ��. ��.4��.�7�423��.3���3�� �7� �3���. ��@�3� .��8� ��� � >����� �#�2��� ���� # �� 4�a34,4� ���� =3���� >����� ���1�� �� >������ @� � �2.�3���� 2=� . �� . ��.4��.�*�(���*�(������*�(��@ 37 �@� �� .�.3 .37���=� ,>� 3� �.��. ��. ��.4��. �*�(���*�(1�� �d� *�+,���.����� *�(5��*�(d��*1(1��*�(1��*�(���*�(5�����*�(d��# ����@� .� ����=3����>�������������>������ @� ��2.�3����8 �4�*�(1�� ���� #�2��� 1�� ��.� �7.3��� �88�7.� �8� <� 3�.=� ���� � <� .3��� .34�� ��� �,42� � �8� ��� � >����� ���� >���������������� =3�����8�>��� # ��.4��. � $,42� ��8� ��� �>����� !���=3�������>���.���� !���=3�����.� ����� *�� (�� 1����� ����5:-� d���8� � (�� ��1�2��� ���d� � ��1�7� � (1� ����2��� �1��13:� d�5��� � (�� 5����2� ���5��� 5��5 � (5� 1���7�� ���5�-� 5���� � (d� ��512��� ���5�3�-� d��d�� � � *�� (�� ���52��� ����d7�� ��512��� (�� 5����2� �����2� c����2� (1� 5����2� �����7� ��c�27� (�� d�1��� ������� ������� (5� �������� �d�1c��� ���c2��� (d� d����� �c��12� c����2� *1� � (�� ����2��� �5�c����� ��d�2��� (�� 5�����7� �d��1��8� ����2�8� (1� ��5�2��� �5�d��� � ����2��� (�� 5�����7� ����c � ��1c7��� (5� ����2��� �5���� � ��557��� (d� ��c���7� ����c � ��1c7��� *�� � (�� 1�c�2��� ����13�-� d��d�� � (�� ���52��� ���5� � ����7� � (1� ����2��� ����53�-� d����� � (�� 5��d�2� ����c-� 5�c5� � (5� 1�c12��� �5��18� � d��57� � (d� ���5���� �1���3� d�d��� � %�<��,�� ��1�jj� ����djj� ��d�jj� 9(��e�� ������ ����� ��5�� *�g1�. ����,� =h�c����� �= ��8.� �)�@3�����*�g�c. �%�2 ,� =h�c����� �)���*1g�c. �%�2 ,� =h�c��c�� �)���*�g� .� /� 7 h�c� ����� �)��� (�g�!)�� /�.� � ,.3���� (�g�!)�� /�.� � ,.3���� (1g�!)�� /�.� � ,.3�1�� (�g��'�� /�.� ����� ,.3����(5g��'��/�.� � ,.3�1��(dg��7���@ 3.���� /��� �3����7��,4��8����@���2=� �4����..� � ��� ����.� 3��3837��.�=��388� ��.��.���e���<����8� 3��3837��7���� ���� ���� )����=3����>���.)����=3����>���.)����=3����>���.)����=3����>���.���������������������������� # �� 3�.� �7.3����4����<� 3�.3� ����� � <� .3��� .34����� . �� ����=3�������>���.���@� � 8�,��� .��2�� 3��3837��.� �#�2�������# ��7�423��.3���*�(��> ��,7���. ��4�a34,4� ����=3������� ��������>���.���� �8�>���@ 37 �@� � .�.3 .37���=� ,>� 3� �.��. �� � .��8�. ��. ��.4��. ��8�. ��7 �>��# 3 �43� .�2���,�� .��>���. ��8�*�� �7�3<���7�4>� �.3<��=� 8�<� �2�����<3 ��4��.������>.34,4�.34�� 8� �<���.�.3<�� � �@. � �8�>���.�@ 37 � ���� � .�� 8� 4�.3����8� 3� � �> �.� =�. �.37�> ��,7. � � ,�.��� 3�� 3� � � ����=3�������>���.����# ����@� .�=3�����8� ��� ���������>���.����@� ��2.�3����8 �4�. ��.4��.�*�(5����� ���� ���� ���� ��� �3�����8�&� ����!����.�(� 3���*� <� .3��� �.� ���� �������������������� ����@�3� .���� ����@�3� .���� ����@�3� .���� ����@�3� .�������� # �, ���� ����@�3� .�@� � 8�,��� 3��3837��.��4����. ��. ��.4��.�7�423��.3����8�<� 3�.3� ����� � <� .3��� .34�� �8� . �� 7 �>� �#�2��� ����*�@�<� �� . �� ����� ����@�3� .� 8�,��� 3�7 �� ��� ,>� .�� 1��������8 �4�. ��. ��.4��.�*�(��@ 37 �@� � .�.3 .37���=� 343�� �.��*�(d��*1(������*�(������ ,>� 3� � .�� . �� � .� �8� . �� . ��.4��. �� # �� ��@� .� . �, ���� ����@�3� .�@� � 8 �4� . ��.4��.�� *�(1�����*�(5�����3.�@� ����������� � )����=3�����.� �)����=3�����.� �)����=3�����.� �)����=3�����.� ����������������� ��.� �7.3����88�7.� 3��3837��.�=� 3�8�,��7���. �� ����=3�����8�>��� �#�2�������# �� 3� � .� ����=3���� ������ .� �����@� ��2.�3���� 3�� . ��.4��.��*�(������ 3.�@� � .�.3 .37���=� 343�� � .�� . �� . ��.4��. �� *�(���*�(5� ����*�(d� ���� ,>� 3� � .�� . �� � .� �8� . �� . ��.4��. �� # �� ��@� .� ���� =3����@� � ����d�.� �����2=�. ��. ��.4��.��*�(5��8�>������� ���� #�2���������.� �7.3����88�7.��8�<� 3�.=����� � <� .3���.34���������� ����@�3� .����� ����=3�����8� >��� �# ��.4��. � )����=3����>����� ���� )����=3����>���.��� ���� ����� ����@�3� .� ���� )�����3���� �.� ����� *�� (�� ���52��� ��5���8� � ��5���8� � ��5� �-� (�� �������� �d����2��� �d����2��� ������ � (1� ���d��� ������3:� ������3:� ���58�3� (�� ���c���� �1�������� �1�������� ����:-� (5� ���52��� �c���� �:� �c���� �:� ���d-� (d� ����2��� �������� � �������� � ��5d��:� *�� (�� ��1��� �5����2��� �5����2��� 1���2��� (�� ��1��� 1������� 1������� 1�d��2� (1� ������7� ��1�1���:� ��1�1���:� 1�1�2��� (�� ��1d�� �d5���27� �d5���27� ������ (5� ��1��2� ��������:� ��������:� 1����� (d� ��1��2� �������2� �������2� 1�5c��7� *1� � (�� ���5��7� �1�������� �1�������� ��cc���� (�� ��1��2� �������2� �������2� 1�1�2��� (1� ���52��� �c���� �:� �c���� �:� ��c��� � (�� ���5��7� �5����2��� �5����2��� 1������� (5� �������� �c���� �:� �c���� �:� ��d�8�3� (d� �������� ������7�8� ������7�8� ����8�3� *�� � (�� ��1��� ��5���8� � ��5���8� � ��5���-� (�� �������� ��5����2� ��5����2� 1��57�8� (1� ������ ������:� ������:� ���� �-� (�� ����7��� ������8�3� ������8�3� 1�����8� (5� ���5��� �������:� �������:� ��1�3�-� (d� ���52��� ������8�3� ������8�3� ��5� �-� %�<��,�� ����j� ���5�jj� ���djj� 1���jj� 9(��e�� ����� ��5d� ����� ��5�� *�g1�. ����,� =h�c����� �= ��8.� �)�@3�����*�g�c. �%�2 ,� =h�c����� �)���*1g�c. �%�2 ,� =h�c��c�� �)���*�g� .� /� 7 h�c������ �)���(�g�!)��/�.� � ,.3����(�g�!)��/�.� � ,.3����(1g�!)��/�.� � ,.3�1��(�g��'��/�.� � ,.3� ���(5g��'��/�.� � ,.3�1��(dg��7���@ 3.���� /��� �3����7��,4��8����@���2=� �4����..� � ��� ����.� 3��3837��.�=��388� ��.��.���� �5�e���<����8� 3��3837��7���� � ��� *�+,���.����� #�2���5��! �<�3�3���.�4>� �., ��� ���.3<�� ,43�3.=����� �3�8�����, 3���. ��� �@3���>� 3����8�!��� �, 3���������c� /��. � �3 �#�4>� �., �� �k9�� *,43�3.=� �e�� '�3�8���� �44�� /�a�� /3��� �<��� $�<�42� h��� �d��� �1��� �5��� ����� �15��� �7�42� h��� ����� �c��� ���d� ����� ������ ���,� =��c� �c�c� ���d� ����� ����� ��c�d� %�2 ,� =��c� ���5� ����� �c��� �5��� �d��1� /� 7 ��c� �d��� �1�5� ����� �1�d� ��5��� �> 3���c� 1���� ���d� ����� �d��� ������ � 9��7�, 3��9��7�, 3��9��7�, 3��9��7�, 3��� � ���� � . ��<� 3�.3� ��8��� ����>��� ��!)��/�.� � ,.3���� �!)��/�.� � ,.3���� �!)��/�.� � ,.3�1�� ��'�� /�.� � ,.3���� ��'�� /�.� � ,.3�1� ���� ��7��� @ 3.��� �@��� 2�..� � >� 8� 4��7�� 8� � � <� .3��� �.� c. � %�2 ,� =h�c� ���� �)�� 3�� 7� �� �8� >��� =3���� ���� ���� =3����� )��� 3.� 7��� 2�� 7��7�,����. �.��. � �� 3a�<� 3�.3� � �,���2�� �@�����$�<�42� �������� � <� .����.���� �)�.�� �2.�3�� 3� � �>������� ����=3��������� ���� '�8� ��7� '�8� ��7� '�8� ��7� '�8� ��7� ���� � �����=4�, ���cc���;�3.���).�.� � �>� .4��.��8��� 37,�., ���$�.3������� 37,�., ��� .�.3 .37 � � <37��� �� 37,�., ��� ).�.3 .37 � ��� ��� ;)��� �93.��� 8 �4� �� �� /�� )��� l�� l�� &�� ��� ���� ��� !�� /77���,4���cc���! ��,73���(���.�2���9 �> ����.� .�.��>,2����7���� ���3.3������d��� ��)�� ���5�� � ��� � 2��-� �8� �� 37,�., ��� ).�.3 .37 � �8� �������� �� �������� � �, ��,� �8� ).�.3 .37 ��� ).�.3 .37 � 3<3 3����/3�3 . =��8�!����3����&�<� �4��.��8�. ��!��>��h �'�>,2�37��8��������� � >�d1�� 9 ��� ��� '�� ���� '�� !��3 �..=�� �cc��� %�7.� � �88�7.3��� � �@. � ���� � <� .� 3���a� 3�� >��� �!3 ,4�� �.3<,4�����<� 3�.3� ��388� 3���3��.34���8�8��@� 3�������4�., 3.=������� ����9 �>�)73������1��� ��c��15�� %� 3��.���� !�� �c���� %�� �3������ ����= 3 � �8� �4�� +,��3.�.3<�� . �3. � 3�� �� ���� >���� ��� �, .�� �� .��������������� �� 37��)73������cc������ /�-� �<���'��0��*���c�1��# ��>����"a��3���! � �><.���.���$�@� �� 3��>��d��� )�7 ����9��!���/��!������<��!��0��0�.3=� ��0��)��:��<������(��!��0���,:3������1���88�7.��8� � <� .� .34����� ����+,��3.=�3��>����%� 4��)73�����������d��dd�� (� 23. -33��$��/���cd��� ��3.3���4�.� 3��� 8� � 2 ���3��� 8� � 8���� � 3��'� .�<� �3 . 37.��!,2�37�.3����8� . �� /� 7�@� 3 . 37.�9�443..���0�4 �4����/� 7�@��>>���5������ microsoft word final.doc � �������� ��� �������������������������� ������� ��!"�#�$#%�&�#'$�(� #��)��!�*� *+�#��� ��������� ��!"�#�$#%�&�#'$�(� #��)��!�*� *+�#��� ��������� ��!"�#�$#%�&�#'$�(� #��)��!�*� *+�#��� ��������� ��!"�#�$#%�&�#'$�(� #��)��!�*� *+�#��� ������ ���� � * �*$����� * �*$����� * �*$����� * �*$�����**$�� ���**$�� ���**$�� ���**$�� ���,���,���,���,������ ���� ���+��+� -.����+��+� -.����+��+� -.����+��+� -.�������+��(����/��+��(����/��+��(����/��+��(����/������0��%��1.��. ��0��%��1.��. ��0��%��1.��. ��0��%��1.��. 2222��������'��!� 3/�����'��!� 3/�����'��!� 3/�����'��!� 3/��������� �&�3���4-��5�! �6� /��������7�2! �6� � ���� �5�8 �����9�&/ 8/4�/����0 .����:�/3� /59� �"�85. � ��%�35�������;��� .����������0 .����� �� � 4���/����.5 � ���--� -.����<=�-�/��8�-� 0�9�>� � ��0�9�>� � ��0�9�>� � ��0�9�>� � ���� �� /8���������4���5/���-�5 ����4�/ ��� �>�� /����� �>�� �>�� ����-��5��9/���� � �; 5 �85�; 5 �85�; 5 �85�; 5 �85���� ���� �� 6/���� �?4� /-��5� >� � 8���.85��� �5� 5 �� �� �5�8 �����9� �/���� "�;� �5� 9� �6� 0 .���� :�/3� /59� �. /��� 5 �� ;� �� �� ��� 5�� �3��.�5�� 5 �� �66�85� �6� 4���5/��� ��� /59� ��� 5 �� 4� 6� -��8���6� /8�� 3� /�59��**$�� ���,��� ���?4� /-��5� �8�/3��� 5>��3�� 5 ��5-��5 �� > /8 �>� ���/3/����/�5��5>���/ 5/�85�4�55� � ��� /����� �>�����4�/ ��� �>��� �� /����� �>� ���6�. �5 ��5-��5 �����4�/ ��� �>� ����/� 5�5 ��5-��5 ��!���5/������ /5/� �>� ���������� ��� ���� ��� /�� � -���� � �� �?4� /-��5� >� � � ������ /�� �� ����-/@��� 8�-4��5�� ;��8a� �� /����*��&��>/5 �5 ��� �4�/8�5/�� ��'5���� ��-�����-��5�4 �85/8� �>� ��6����>���/�� �/ /���8 �4 ��*� .�5 � �3������5 �5�8�� � � 4�8/���4 ��.8��� /� � �9/��� �> � ����� /�� � -���4 ��.8���5 ��-� 5� ���,��5� ������> /8 �>� � 5�5/ 5/8���9� /-/�� �>/5 � 5 �5��6���� /�� ��� -���� !�/ ��� �>� 4���5/��� �>��� ;�55� � 4� 6� -��8�� 5 ��� /����� �>� 4���5/���� !���5� �/� 5�� � �/� � 4��/8������ 5� /��� 4/a���5 � 4��/8������ ������ �/��>�/� 5�� � �/�� 9/����>� �� 6�.���;�55� �/��4�/ ��� �>�4���5/����!�/ ��� �>�4���5/����5��� 4�8/����6��2<�8-�b��<�8-�� �����8-��/��� �>�5�� �>��/ 5��8��/ �2<�8-�7��<�8-����� /��� 5�� /����/ 5��8��/ ����8-c� 6�.���5 �� /� � 5�� �/��9/�������,��5� ���������5 ����>� 5�9/�������d��5� �����>� �6�.���/�� /����� �>�. /����� 4�8/����6��<�8-����<�8-��� � $�5 ��.85/���5 ��.85/���5 ��.85/���5 ��.85/������ ���� */8��/ �5 ��-� 5�/-4� 5��5�8� ����8 �4�/��5 ��>� ����$5� / �5 �� 5�4���6����6� ��;�.5�<��e��6�5 �� >� ��f �4�4.��5/������������ �/ �5 ��6�. 5 ��� �� 5�4 ��.8� �����8�� .-� ��6� /8��/��5 ��>� ��� >/5 �������.���4 ��.85/��� ���/���6 �-����5�����-/��/���5�� ��*/8���88.4/� �������e��6�5�5��� 8 �44���� ��� /��> /8 �;� �� /8�� / � 8.�5/3�5��� /�������� ��a � �� � ��� /��������2��� �� �3� ���� 5�5���4 ��.85/����6� /8�� /���������� � / ��,���,� ��a �-�5��� ��$'�����������-4� ���>/5 �-/�� /?5/� �� �������� � � � ��-� 5� ��.;���� /5 � 4 ��.85/��� �. /��� 5 �� 4� 5� 5 ��� ��8��� � ���� 5 �� � �>5 � /�� 4 ��.85/��� 8�-��-�/��9� 6 �-� �����8�5/��� �6� ����� 6 �-� 5 ��/5/����� 5�� /� � 9/���/��� -��� ��3� /�5/� ��)(g ���+��� ��3� /�5/� ��5�4 � ��5�8�3� �d��2�e��6�;� ���2����e��6��. ����� <�e� �6� 5 �� 4���5��� �-��� /8�� � ��� �+/� � ���� )�-/��� �ddd�� ���� �������� � � � �55�/���� ��� �9� ��6� .66/8/��89� /�� 6����� �� -��� 5� � 5/-�5�� �h�-���� �dd��� .��� 5 � 5 �5� 5�� 6���� 5 �� � �>/���4�4.��5/����5 ����-����6� � /8��/���������� �>�.��� �3��5��;��/�8 �� ���;9��3� �,��e� �3��� /�� 5 �� ��?5���� 9�� �����4 ��.8�� 5 �� �i./ ��� i.��5/59� �6� ���/5/����� 6����� 9/����-. 5� ;�� /�8 �� ���5 �.� �/�8 �� /���5 �5�4� �� ���� ��� -��5� 5 / � 8 �������� /8�� 8/��5/ 5 � �3�� ;���� >� a/��� 5�� ��3���4� ��>� 5�8 �/i.� � �-���� 5 �-���� / ����.-;� ��6�4���5�4�4.��5/���4� �.�/5�� ��� � �4 �6�.���/�6�.��8������ �/��9/�����6� /8���$ ��-���d,����� ��4���5���� /59�/�6�.��8� ����6�� ���/���?��8 �4�� �>5 � �5�����5�� /-/��5/��� �5��� 4�8/6/8����6�� ����4 �5� 9�5 � / �� � 4/ �5/�������.�5/-�5��9�9/����� 45/-.-�4���5/������ /59� ���;�� � 5 �� /8�� 4���5� 5�� � �>� 4 �4� �9� ;�5 � /�� /5 � �� /��� ���� .��� � �.��� 4� 5 � ;9� .5/�/@/��� -�?/-.-� ��/��5���� �9�� 4�8������>�5� �> /8 �.�5/-�5��9����� �5��;�� 5�8 �4�4 ��.85/����+/� � �,� +� -.���5����� �5�������dd����$����� ��9�4�4.��5��� /8��6/��� �5 ��/�5 ���� 4�8/6/8�8�-4�5/5/���;�5>����5 ��4���5 �/ � /� �> /8 � �-�5/-� � � .�5 �/����>� �� �/��9/����� ��5 ��8��5 � 9�� 4� ��9�4�4.��5���6/��� �>/5 � >/��� 4�8/��� ����� 5�� .��8���-/8� .5/�/@�5/��� �6� 4�8��� 4 �6. �� � �>5 ��6�>��� � ����4� 5 � ���� ��.85/����6�� �/��9/����.�/5�� ������� � � �� ���;���� �3� ��� 5.�/� ����5 ��9/��������� /59� ���5/�� /4��j/���9�����)��5 ���d�d��. /��� ��>/���3� /�59��6�8 �4 ��;.5�5 ��8��8�45��6��45/-.-�4�4.��5/������ /59�6� �-�?/-.-�9/���� � � ��5�9�5�;����6/�. ����.5��&.�8�����d,����$��8��5 � 5�5��5 ���� �/� �4 �4� /5/���5 �5�8�� � � 4�8/��� /�8 �� � � /�5 �� �� 4�8/6/8�8�-4�5/5/��������66�85 �� �/��9/���� ��**$���dd�������i.��/59� �0� /-��5� ������dd����'�3� ��� 5.�/� � �3������5 �5�8�� � � 4�8/���/�8 �� � �� �/��9/�����$ ��-��5�������dd���� )�>�3� �� 5 � �� / � �� 5 / �� 8 ���� �6� 5 �.� 5�> /8 � ��3�8�5��� 5 �5� � �/�� 9/���� / � .��66�85��� ;9� 4���5� ��� /59� ���� .; �-��/9��� ���� !����/�44���� �dd���� �� �.-;� � �6� �4� 5 � ���.�8�� �5� ����� �d,d�� �� �� /��/8�5��� �� 8. 3/�/��� � ���5/�� /4� ;�5>����4���5�4�4.��5/������ /59� ���� /8�� � �/�� 9/�����:��� �5 �� 4���5���8���/5/����� �/��9/����4��5��.� � �;����6�.���5�� ��8 �>/5 ��<�5������ 4���5 �-�����a/5����d,����j� a �8���.85����5��**$������9-�. ���dd��� .��� 5���5 �5�>/5 /���� ������6����5�����4���5�-����� �/��9/����/�8 �� ���>/5 �5 ��/�8 �� ���6�4���5���� /59�/ � 4�85/3�� �6�3� /�5/� �� ��8 �3� /�59� � �8� 5�/��5/��� �4 ��.8/���8�4�8/59��������i.�5���.-;� ��6��66�85/3��5/��� �4� �.�/5� � ���5 �5��?� 5 ��� ����/��4 ��.8/���4��/8�� ����� 4/a���5 �����.�5/-�5��9�� �/��9/�����+/��� ��5������ �dd���� 45/-.-��.-;� ��6� 5/��� �4� � .�/5� � ��� / � ��4 � �i./ /5�� 6� � �;5�/�/���-�?/-.-�9/���� 5 �5� /�8 �� � � >/5 � /�8 �� ��� �.-;� � �6� 4��/8�� � 4� � .�/5� � ��� ��**$�� �dd<��� )/� � � 9/���� 4�5��5/����6� 9; /�� /8��/ �4 /-� /�9��55 /;.5���5��4 �6. ���5/��� /���� �� ����.-;� ��6�4��/8�� ����� /� � � 4/a���5���� /59��$5�/ �� .-���5 �5��**$� ���,�-�9��� ��9/���� /� � �/6� /� � ��.-;� ��6� 4��/8�� �4� �.�/5�� ���>/5 �-� ��� ��i./3����5��6�����6/����� 4/a���5 �4� �4��/8�� �� ���� . ���� :��� �5 ���;�3��8/ 8.5��8� ��/5�>� �6��5���8� � 9�5���?�-/���5 ���66�85��6�4���5/������ /59���� 5 �� 4� 6� -��8�� �6� �**$� � ���,� >/5 � 5 �� �;k�85/3� � �6� �; � 3/��� 5 �� � �>5 � ���� 9/���� 4� 6� -��8���6��**$�� ����,� /8���5��� ������6��/66� ��5�4�4.��5/������ /5/� ������6/��/����.5� 5 �� �45/-.-� 4�4.��5/��� ��� /59� ���� 4���5/��� 8��6/�. �5/��� �6� /8�� 3� /�59� �**$� � ����,� 6� � ;�55� �� �>5 ����� /� � �9/��������� ���� +�5� /�� �����+�5 �� +�5� /�� �����+�5 �� +�5� /�� �����+�5 �� +�5� /�� �����+�5 �� ���� ���� ��6/�����?4� /-��5�>� �8���.85����5�5 ���� �5�8 �����9��/����"�;� �5� 9��6�0 .����:�/3� /59�� 0 .�����. /���5 ��;� �� �� ����6����<��� �� �/��>� �8 � �85� /@���;9� /�59����-�5�?5. �� �3/��� 4)�3��.���6�<���� �� ���?4� /-��5�>� �8�-4 / ����6� 5>��3��5 ��5-��5 �> /8 �>� ���/3/���� /�5�� 5>���/ 5/�85�4�55� ��l� /����� �>�����4�/ ��� �>��� �� /����� �>� ���6�. �5 ��5-��5 ����<�8-��� ���8-����� /�� �-������<�8-����<�8-����� /�� �-������<�8-������8-����� /�� �-����7��<�8-����<� 8-����� /�� �-��������!�/ ��� �>� ����/� 5�5 ��5-��5 ���2<�8-�b��<�8-�������8-����� /�� �-����� �2<�8-�b��<�8-�����<�8-����� /�� �-������2<�8-�b��<�8-�������8-����� /�� �-������2<�8-�b��<� 8-�����<�8-����� /�� �-������2��8-�b����8-�������8-����� /�� �-������2��8-�b����8-�����<�8-� ���� /�� �-������2��8-�b����8-�������8-����� /�� �-����7��2��8-�b����8-�����<�8-����� /�� �-����� � �� �?4� /-��5� >� � ��/�� �.5� /�� �� *����-/@��� ��-4��5�� ���8a� &� /��� �*��&�� >/5 � 2� �4�/8�5/�� ��� ��.�/5�4��5� /@��>� �����-�����<�-��!��5�5��4��5��/ 5��8��>� ����<�-�����;��8a�5�� ;��8a��/ 5��8��>� ���-��� �� ����/�� ��6� /8��3� /�59��**$� ���,�>� �� ����5 �� 4���5����5�5 �� �����6������9 ��5 �� 4���5/���5>�� ����/�� �/����8 � /����*�>�5�� �>����� /���5�� /����/ 5��8��>� �� -�/�5�/�����88� �/���5��5 ��5 ��5-��5��� ���?4� /-��5���4��5 �>� ��6� 5/�/@���>/5 �,���<������� �������<�a�� �����6�#��!��0��'�����h��� � 4�85/3��9�� ���5 / ���� ���6�. �������6.����� ���6��5 � � 6� 5/�/@� �>� ���44�/���� �;� ����5�5 ��5/-���6�6/���������4 �4� �5/�������5 � �.� �9�/�8� 4� �5��� �d� !���5/���&�� /59��66�85 ������ ��*/8�� /�5�� 5 �� �/��� � �� �-�/�/��� 5>�� 5 / �� �6� . ��� >� � 5�4� � � ��� /�� 5>�� �i.��� /� 5���-��5 �� �5� 4��/8���/�/5/�5/��� 5�����������5 � ��5��85/3��5/��� /��� 5�����% �>5 �4� �-�5� ��6�5 ���?4� /-��5� >� � 5.�/���8�� /�� /���4���5� �/� 5���.-;� ��6�5/��� ��� 9�-�55� ��88.-.��5/���7�8 �4�� �>5 � �5������9/����7�9/����8��5 /;.5/���8 � �85� �>� �� 5.�/���8�� /�� /���4���5� �/� 5���.-;� ��6� 5/��� �7�4��/8�� �� ����5 ��6�4��/8���� � �/�� �.-;� �4� �4��/8���������� �/��>�/� 5�� � �/�� 9/����� 5 �>�9/����� ;/����/8��� 9/���� ���� � 3� 5� /���?��� �� 8 �4 �>� �� � 3� 5��� �5� 6.���-�5. /59�> ��� d�e��6�5 �� ��� �5. �����������9����>�/��8��� ��� ��� �/������ 5 �>�9/����>� ����k. 5���5����e� -�/ 5. ����3����1.��5/5�5/3����5��>� �� .;k�85���5������9 / ��6�g� /��8����# g�������-��� ��6� 5 ��5 ��5-��5 �>� ��8�-4� ���. /���&.�8��f �+.�5/4���*������� 5��&+*����%�-�@�����%�-�@�� �d,���� ���� *� .�5 �����&/ 8. /��*� .�5 �����&/ 8. /��*� .�5 �����&/ 8. /��*� .�5 �����&/ 8. /������ ���� !���5� �/� 5� /�8 �� ���4 �� � /3��9� ��8 /���-�?/-.-�� �4��a� ��/������!���5� �/� 5� /�8 �� ��� ��-� 5� �?4����5/���9� .4� 5�� <2� &��� �6��>� /���� / � 4�85/3�� �6� 5 ��5-��5 �� 5 � ��65� � /5� ��� �9� ��8 �����4��5��.��g� /�5/���/��4���5� �/� 5�>� ��; � 3����-����5 ��5 ��5-��5 ��$5�>� ��; � 3��� 5 �5� >/�� � 4�8/��� /�8 �� ��� 4���5� �/� 5� > /8 � >� � �;3/�. � �' � � �5� ����� �dd�c� h��� � ���� +/ �� /���dd,���$5�>� ��� �� ����5 �5�4�/ ��� �>�4���5/���4� 6� -���>����5 ��� /����� �>�4���5/���� !���5/���4�55� ���2<�8-�b��<�8-�m���<�8-� �3/������ /�� �-��� �>��� /� � � �/� 5�5 ���5 �5��6� �<�8-������8-����� /�� �-������ � � �/������!���5� �/� 5��3� �5/-��� ��66�85���;9�4���5/������ /59� ��� +� -.���5����� � �� /� � 5� 4���5� �/� 5� ���,��� 8-�� �5� -�5. /59� >� � 6�.��� /�� �� 4�/ ��� �>� 4���5/��� >/5 � �� 4�8/����6��2<�8-�b�<�8-�����<�8-� �3/������ /�� �-�������5 ����>� 5�4���5� �/� 5�>� �6�.���/�� /����� �>�4���5/����6��<�8-������8-� 4�8/������� /�� �-����� �/��� �4 ��.85/���>� ��66�85���-� a���9�;9�4���5/������ /59���/��� ��.-;� � /������ 5 �� 5 ��5-��5 � /�8 �� ��� ��-� 5� �?4����5/���9� .4� 5�� <2� &��� ��/��� ��� /���� 6��>� /��� 5/-��� $5� >� � �>�� 5 �5� /� � �4���5/������ /59�4 ��.8��� /� � ��.-;� ��6�5/��� �-����� �-�<2�&�����>� � ���� � 4� ��8�/���/��5/��� ��.-;� �>� ���5/8���> /8 ����/�� ��8 �����4��5��.�6 �-��,�&���������>� � �� #.-;� ��6�5/��� �-���>� �6�.���5��;�� /� � �/�� /����� �>�5 ���4�/ ��� �>��$�� /����� �>�4�55� �� �<�8-������8-� 4�8/��� �>��� /� � �5/��� �5 ���5 �5�/��4�/ ��� �>��� � ��� ��� ��� ��� ��� ��� �� �� ��� ���� � � �� ��� �� � � �� ���������� �� ��� �� �� �� ���������� ������������� �������!"�#���$��%����$�& �������!"�#���$��%����$�& �������!"�#���$��%����$�& �������!"�#���$��%����$�& '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� '����(��!"�#��� $��)����$�&�%����$� ���� �/�������/��� ��9��-/8 ��3� �5/-��� ��66�85���;9�4���5/������ /59� � �� � .�5��� ����>����>/5 �)� �����dd����+/��� ��5�������dd��� �4� 5���5 �5�5 ���.-;� ��6��85/3�� 5/��� ���8�/����.�5/�� ��8 /�����8�� 5��5�5/��� ���� /59�;9� ���/���> /8 �>� ��� ���44� ��5�/��5 �� 4 � ��5� 5.�9�� $��5 ��4 � ��5� 5.�9�/5�>� ��; � 3���5 �5�5 �� /����� �>�4� 6� -���>����5 ���4�/ ��� �>��!���5/��� 4�55� ��5 �5�/�8�.�� ���� /�� �-����� ��4� 6� -���>����5 ������ /�� �-����5�-�5. /59��� �� /� � 5� 5/��� �-���>� �6�.���/���� /����� �>�4���5/���>/5 ��� 4�8/����6��<�8-������8-� �3/������ /�� ���� ��� !���5/���&�� /59��66�85 ������ ��*/8�� -��� ���� 5 �� ��>� 5� 5/��� �-���>� � 6�.��� /�� 4�/ ��� �>� 4�8/��� �6� �2<� 8-�b�<� 8-���� �<� 8-� �3/������ /�� �-����� & 9�-�55� � �&+���88.-.��5/���>� � �8� �����5��<���9 � /�5� 3��� 5� 5/����5�2,�&��� ��/���2��� $5� /�8 �� ��� >/5 � /�8 �� /��� 4���5� ��� /59� ���� 5 / � 4 ���-���� >� � 4 �3/�. �9� ��-�� 5 �5��� ;9� -��9� >� a� � ����.a�� �� �dd,c� �� ���� �d,,c� *� /��� �dd,c� *� -���� �dd���� $�� 4�/ ��� �>� 4���5/���4�55� ����2��8-�b����8-�������8-� �>��� /� � �3��.� ��6�� 9�-�55� �5/��� � 3� 5�� � �/���2����5���� 9�-�55� �4 ��.85/���� ��66�85���;9�4���5/������ /59� $�8 �� ���4���5���� /59�/�8 �� ���8 �4�� �>5 � �5����%*���. /����� �9� 5����> /8 �5 ���� ��.���9� ��8 �� �������5 / � � .�5��� ���>����>/5 �5 �5��6�+/� �����)�-/����ddd���� � �� ��>� 5� 4��/8�� � -��� >� � 6�.��� /�� 4�/ ��� �>� �3/��� ��� /�� � -��� > /8 � /�8 �� ��� .4� 5�� 4���5/��� ��� /59� �6� ��� /�� �-��� /�� /����� �>�� � �� /� � 5� �<������ 4��/8�� �-���>� � 6�.��� /�� /����� �>� 4�8/����<�8-����<�8-�������� ��6�.��� /� � 5�>/5 ���2<�8-�b��<�8-�������8-���2�� 8-�b����8-�������8-� 4�8/���� � 4�85/3��9��� ����>� 5���22����4��/8�� �-���>� �6�.���/��4�/ ��� �>� 4�8/����6����2��8-�b����8-�����<�8-����;������� � ��� +� -.���5����� ��� � �� �� �� �� �� �� � �� �� ���� � � �� ���������� * + , � ����������������������� �������!"�#���$��%����$�& �������!"�#���$��%����$�& �������!"�#���$��%����$�& �������!"�#���$��%����$�& '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� '����(��!"�#���$��)����$�&�%����$� � �/������� �4�� �>5 � �5����%*��� ��66�85���;9�4���5/������ /59�� '/����� �>�4���5/��� �>��� ����� �4��/8��� 5 �����.;��� �>����� 5 / �>� ��;3/�. �� � 5 �� /����� �>�4���5/��� ���-� ��4�4.��5/��� �"/�.���d,������� /�� �-����� �� �>��� ����� �4��/8�� � 5 ��� ��� /�� �-���� � �5� / �� /� � � 4��/8��� ����5 � ����22� 8-��>� � 6�.��� /�� /����� �>� 4���5/��� �5� �� 4�8/��� �6� �<� 8-��� �<� 8-� ���� 5 �� ��>� 5� 4��/8��� ����5 � ����,�� 8-�� 6�.����� /�� 4�/ ��� �>� 4���5/����5��� 4�8/����6��2<�8-�b��<�8-�������8-�� � � �2� !���5/���&�� /59��66�85 ������ ��*/8�� ��;������!���5/������ /59��66�85 ����4���5�8 � �85� ��9/��������9/�����55 /;.5� ��6� /8��3� /�59��**$� � ���,� � ��5-��5 � !��/8�� � -��� !��/8��� ����5 � �8-�� % �/�� �.-;� � 4��/8����� '5� /��� 4/a���5 � 4��/8����� ������ �/�� >�/� 5�� ���� % �/�� 9/����� �5� ����� '5 �>� 9/����� �5� ����� )� 3� 5� $���?� �e�� ��� <������ ����2;8� ��<��k� ,,���� �d�,�8� �����;� ���d�� 2��,�� ��� ������� ���22;8� �<<�d � d������ �����;8� ���2�;8� <���;8� ������ �2� ��������� �����;8� ����d6� ��d���� ������;8� 2���28� <���;8� 2<�,2� ��� �d2��8�� ���22�� �d2��8� ��d�d�� ����2�;8� ��d��8� ��d��8� 2��2�� �<� �d2�2�;� ���,�8� ����,�� ������� �d���8� ��,��� ��,��;� ���22� ��� ������;8� �����;8� �,��,�� �2���6� �d�,,8� ��2d�;� <���;8� ����2� ��� 222�2;8�� ����2�;8� �,��d�� ����d8� ����;8� 2��<�;8� <�2�;8� ������ �,� �<��,8�� �2�;8� �d���;� �,����� �2�d<�� 2���;8� ��,�8� ����<� �d� �d��;� ���,�;8� �<���/� ����26� ���<�;8� �����;� ��2��;8� ����,� ���� 2�<������ ������;8� �<��� � �����6� ���,�;8� 2��d�;8� ��2<�;8� 2����� ���� 2��;8�� �2����;� �d,��;� ������� �����;8� 2���;8� <���;8� 2��2�� ���� �22���� ���,��;8� 22��,�� �����;� ������;� ��d,8� ��dd8� 2����� "�3����6� /��/6/8��8�� ���<� ����� ����� ����� ����� ���<� ���<� #'� �g��e�� ���dd� 2��<� ����� ��,�� ��d�� ����<� ������ ���d�� � �/�. � � ;�� /��� ��55� � �� /�� 8�--��� ��� ��5� �/66� � /��/6/8��5�9�� > � �� � 6/�. � � >/5 � �/ /-/�� � ��55� � ���/66� � /��/6/8��5�9�� � '/����� �>��'/����� �>��'/����� �>��'/����� �>������ ���n��<�8-������8-����� /�� �-���� � ���n��<�8-����<�8-����� /�� �� �2�n��<�8-������8-����� /�� �-���� ���n��<�8-����<�8-����� /�� �-���� � � � � !�/ ��� �>�!�/ ��� �>�!�/ ��� �>�!�/ ��� �>����� �<�n���2<�8-�b��<�8-�������8-����� /�� �-����� ���n���2<�8-�b��<�8-�����<�8-����� /�� �-����� ���n���2<�8-�b��<�8-�������8-����� /�� �-����� �,�n���2<�8-�b��<�8-�����<�8-����� /�� �-���� �d�n���2��8-�b����8-�������8-����� /�� �-���� ����n��2��8-�b����8-�����<�8-����� /�� �-���� ����n��2��8-�b����8-�������8-����� /�� �-���� ����n��2��8-�b����8-�����<�8-����� /�� �-���� � !�/ ��� �>� ���-� ��� �/�����4��/8���5 ��� /����� �>����� /�� �-��� ���-� ��� �/� �5 ������ /�� � -���> /8 �-�9�;���55 /;.5���5��5 ������5/3�� ���5/�� /4�;�5>����� �/���.-;� �����4�4.��5/��� ��� /59��� �� /� � 5�� �/���.-;� �4��/8������22��,��>� �6�.���/��4�/ ��� �>��5��� 4�8/����6��2�� 8-�b����8-��m��<�8-�����5 ����>� 5����<����>� �6�.���/�� /����� �>�4���5/����5��� 4�8/����6��<� 8-������8-����;�������� �� �� �� �-/� 5�;���.��5��5 �5�8�-4�5/5/���6� �� �>5 � � �. 8� �>� � -� ��/��8�� � � 4�8/�����5�5 �� �-��5/-��� /-/��5��4 ��.85/���� �>����� �5 �� ��8�5/���>� ��� �� 4�� �/���3� �8 �>���� 5��� ��h��� �����+/ �� /���dd,��� '5� /��� 4/a���5 �4��/8�����>� � /� � �/���� �4���5/������ /59�5 ��5-��5 ���� 5� � .�5�>� �6�.���/�� 4�/ ��� �>�4���5/��� ������� /�� �-��� ��� /��/6/8��5�9�-� �� 5� /��� 4/a���5 � 5 ������ /�� �-���� )/� � ���,����� 5� /��� 4/a���5 �4��/8�����>� �6�.���/��4�/ ��� �>�4���5/����5��� 4�8/����6���2<�8-� b��<�8-�����<�8-�����5 ����>� 5���������>� �6�.���/���� ��4�/ ��� �>�4���5/����5��� 4�8/����6� �2<�8-�b��<�8-�������8-�� � �. ����� �/��>�/� 5���8 �� ���>/5 ���8 �� /��� 4�8/���> /8 �-�9�;���55 /;.5���5��5 ��� ��5� � 8�-4�5/5/����.��5�� /� � �4�4.��5/������ /59�� �5 ��8�� �i.��8���6���8 �� ��� 4�8/����' � ��5� ������dd��������5������������j�����5�������������� �� /� � 5�� �/��>�/� 5���2�d<����>� �6�.��� ��� +� -.���5����� /��4�/ ��� �>�4���5/����5��� 4�8/����6� �2<�8-�b��<�8-�����<�8-����� 5 �� ��>� 5�� �/��>�/� 5� ��d�����>� ��� ��6�.���/��4�/ ��� �>��5��� 4�8/����6��2<�8-�b��<�8-�������8-�� !�/ ��� �>�4� 6� -���;�55� � 5 ��� /����� �>� �>/��� /� � � ���� 9/��� � ������� /�� �-��� �� �� 4� 6� -���;�55� �5 ������ /�� �-����� �� /� � 5�� �/��9/�������,��5� �����>� � �8� �������;������/�� 4�/ ��� �>��5��� 4�8/����6���2<�8-�b��<�8-�������8-�������>� 5�� �/��9/�������d���>� �/�� /����� �>� 4���5/��� �5� �� 4�8/��� �6� �<� 8-� �� �<� 8-�� � �� ��>� 5� 9/���� �6� 5 / � 5 ��5-��5� -/� 5� ;�� �55 /;.5��� 5�� /5 � ��>� � �.-;� � �6� 5/��� � -���� 4��/8�� � -��� ���;��� ���� � /-/��5�� 5 �� ��8�5/��� 5�>� � �� �/� �>� �4 �;�;�9�4�� � 5�/��5 / �5 ��5-��5�� �8�-4� ���5���5 � ��$5�>� ��� ���3/���5� 6 �-��� �/� � �4� 5 ���**$���dd���5 �5�8�� � � 4�8/����/3� �-� ��9/����5 ���>/�� � 4�8/����%.45�� ����' � -���dd�c�+�������5�������dd��������� '5 �>� 9/���� /�8 �� ��� >/5 � /�8 �� /��� 4���5/��� ��� /59� > /8 � / � �;3/�. � � � /�8 �� ��� 4���5/��� ��� /59�/�8 �� � � 5 �>��$ ��-��5������dd����� �� /� � 5� 5 �>�9/��������d�5� �����>� � �8� ����/�� /����� �>��5��� 4�8/����6��<�8-������8-������� ��6�.��� /� � 5�/�� 4�8/����2<�8-�b��<�8-���� ���8-�� �2��8-�b���� 8-�� �����8-�� �2��8-�b����8-�� ���<�8-�� � 4�85/3��9��� �� ��>� 5�>� � �8� ����/��4�/ ��� �>��5��� 4�8/����6���2<�8-�b��<�8-�����<�8-�� )� 3� 5�/���?��/����5�6����>���9� ��.�� �5 ����������� /��/6/8��5��/66� ��8��>� ���5��;5�/�����.�� 5�� 3� /�5/��� /�� 4���5/��� ��� /5/� �� �.5� �.� �9� /5� 8�.��� ;�� � .-��� 5 �5� /�8 �� /��� 4�4.��5/��� ��� /59���8 �� ��� � 3� 5�/���?��� �� /� � 5� � 3� 5�/���?������2��>� �6�.���/��4�/ ��� �>��5��� 4�8/����6� �2<�8-�b��<�8-�����<�8-� �3/������ /�� �-�������5 ����>� 5� � 3� 5� /���?��2<�,2�� >� �6�.���/�� /������5��� 4�8/����6��<�8-������8-� �3/������ /�� �-����� � �-�5 ��6/��/�� ��6�5 ��4 � ��5� 5.�9�/5�-/� 5�;���8��8�.����5 �5�4�/ ��� �>�4���5/����6��2<�8-� b��<� 8-���� ��� 8-� 4�8/��� ���� /�� �-���� 6�.��� 5 �� ;� 5� 4���5/���4�55� �� �6� /8�� 3� /�59��**$� � ���,� /8��/��5� ��6�4 ��.8/���5 �� /� � 5�� �/��9/�������,��5� ������ � *�6� ��8� *�6� ��8� *�6� ��8� *�6� ��8� ���� ���� �$'�� ������ o0 / /� &/� 9f�� �� /8.�5. ��� $�6� -�5/��� '� 3/8��� 0 �-� ;� /�� �� -��5��� & �a��� �������� �� �a/5��� 0�� �d,��� '5.�/� � ��� 8�-4�5/5/��� ���� 8�-4�� �5/��� �6� 8 �4� 4���5 �� �66�85 � �6� 4�8/��� ��� � �>5 �� ��� ��6� /8���'8/��*� �����8���� /8���0�;��:�/3�����4�����<������������ �����'���p��j�����h��p/�������'��p/��������� � -��5��6�. /���'*$�>/5 � .4� � 9; /�� /8��3� /�59� "/���9�.4�/�d��$���� � -��5 ��6�5 ��'9 5�-��6�*/8��$�5�� /6/8�5/����! �8��$�5������6��'��9��� � /�����4 /�������������44�������2�� ����9-�. �� �dd��� �**$� ���.��� *�4� 5� 6� � �dd��� �������� � */8�� *� �� $� 5��� ��9��;4. �� �������� �� ���� .; �-��/9����!������'��!����/�44�����dd����66�85��6� /� ���� /59�4�4.��5/�������6� 5/�/@� � �5�� �6�� �>5 �����9/�����6� ��>����� /8�� � 9@�� �5/3���� $��/�������� ����2��� .44��-��5�������2� q*/8���; 5���������������dd2r�� �**$� ��������� � */8�� *� �� 8 � $� 5/5.5���� �dd��� �� .�/a� & ��� � � � � �$�� �������� �5 � ����� �������� �*/8��*� ��$� 5����9��;4. ��%�@/4. ��44�������� �**$���������� �*/8��*� �� 8 �$� 5/5.5�����dd�����.���*�4� 5�6� ��dd����������� �*/8��*� ��$� 5�� ��9��;4. ��%�@/4. ���������� ��44�����2��� �**$� ��������� � */8�� *� �� 8 � $� 5/5.5���� �dd<�� �� .�/a� & ��� � � � � �$�� �������� �5 � � �3/ ���� ������������� �*/8��*� ��$� 5����9��;4. ��%�@/4. ��44�2�2��� �<� !���5/���&�� /59��66�85 ������ ��*/8�� ��.�8���!������0�����0��+����� �.� ������&�����+� ?���d,d��*/8��9/��������4���5�9/����3� /�;/�/59� � 4�� ��5���i./�/ 5��5� 4�8/����� �4�'8/���d����<���d�� &.�8����j��%���d,���!���5/���4�55� � ����� �9;����9/������ �4�'8/������<,��<,,�� %�-�@��0���������������%�-�@���d,���'5�5/ 5/8���! �8��. ��6� ��� /8.�5. ���*� �� 8 ��$�5���*/8��*� �� $� 5���� ��j/���9�����'�� ��#�>�(� a��4�2���� %.45������0������*��'��' � -����dd����66�85��6�4���5� 4�8/�������6� 5/�/59���3������� �/��9/�����6��� �9� -��/.-�/��/8�� /8��� 9@�� �5/3��"����$��/�������� ����2���'.44��-��5�����2���<�� )� ����+���dd�����-4�5/5/3��;� �3/�. ��6�6�. � /8�� � 9@�� �5/3��"�������594� �� �>��/��-/?5. ��� ��� .�4.;�/ ��� +�� '8�� ������ � � / � .;-/55��� 5�� �������� � �� /��� :�/3��� +9-�� /�� �� 4����� $ ��-��������+������d,���*�3/�>��6��� ���-/8� � �� 8 ���� /8������/5 �6. 5 � � 5 �5��9����3���� ���� *� ���������� ��������d�� $ ��-��+��'���+�����*��'� a� ��+��'��*� -�������+��+. ������'������& �����dd����66�85��6�4���5� 4�4.��5/��� ��� /59� ��� 5 �� 4���5� �. � /8�� .��� � 5/����9� 6������� 8���/5/�� �� �������� � ��� �� /���'8/����������2�d�2<2� �� ���� +�� '�� �d,,�� ����-�5 9�� *� �. 8�� ����8�5/��� ���� (/���� /�� +.�;����� �66�85� �6� 4�4.��5/��� ��� /59� ���� 4���5/��� 8��6/�. �5/���� +�'� � � / � /�� �� ���-9�� $� 5/5.5�� �6� !� 5� ��.�5�� '5.�/� �/���� /8.�5. ���%�@/4. ��44�����d�� 0� /-��+�����������/��"����/��'����/�����+� -���������+�k/�������������a5 � ���dd����66�85��6�4���5� ��� /59���� /8��� �/��i.��/59��$�5���*/8��*� ��#�> ��������������q*/8���; 5���dd2�����2����,r� "/�.�����+���d,����66�85��6� 4�8/�������6� 5/�/@� ���3�� ����8 ���� ��6��� �594��/�� /8�������� /8��� �8�� � /���������������� +������� +�� ���� +�� ��� *� -����� ��� ��� � �>� . 9� ���� '�� ��� '/��/i.��� �dd��� (/���� �6� -��� �� / /��5��� /8��3� /�5/� �.��� ��/66� ��5�4�4.��5/����9��-/8 �/���������� ���������� �*/8����� ��������<d����� +/� ��+��)���+�����0� /-���+��'��*� -�������+��'��$ ��-���dd���!� 6� -��8���6�#/@� �/��-.5��5 � .��� � �>� 4�8/�� ���������� ����� �/�/���&�3��2�����2��2��� +/� ��+���������)�-/����ddd�� $-4�85��6��� /8.�5. ��� � �� 8 � /���������� � �� �4 ������� � 5 9��� !�4� �4 � ��5����5�>� a �4����o� �� 6� ��6��� /8.�5. �����8 �����/� f� �����5��������� � �� /���*� ����.�8/���& �a����.����,��d�� +/��� ���������������)/�������'��*��*�;� 5 ���dd���!���5�4�4.��5/����66�85 ����� �>5 �����9/����/��>�5� � ������ /8������������,2������d���d��� *� -����+��)���dd���$�6�.��8���6�/ /��5/�������4���5/������ /59����� �>5 ����� ����9/����/����/;��� 4������ 4���� +�'� � � / � /�� �� ���-9�� $� 5/5.5�� �6� !� 5� ��.�5�� '5.�/� � /�� �� /8.�5. ��� %�@/4. ��44�����<��� *� /�������dd,��!�4.��5/������ /59� ���� �. 8�� /�a�-��/4.��5/����66�85��6� � �-���+�'�� � / � /�� �� ���-9��$� 5/5.5���6�!� 5� ��.�5��'5.�/� �/���� /8.�5. ���%�@/4. ��44��d����� ' � ��#��)���+��0��0. .��������0 �-��9��������'�����/���dd����66�85��6� 4�8/������� ����/��� /����� ���5 �� 4���5��� /8��.��� ���5�� �>��8���/5/����$��/�������� ����2������������<�� ' � �����"������)��0 ����������*��%�-� 5����dd����66�85��6� �-��8.�5. ���4 �85/8� ���� 5 ��9/���� 8�-4����5 �����9/�����6��*�2� /8��/��� 9� �� ������������ �*/8�����������������,��,��� ��� +� -.���5����� ���.a�� ��+�����+���dd,��!���5/������ /59��66�85 ����4 ��.85/3/59��6���������-��� ��3� /�5/� ��6� /8�� /�� ���5/��� 5�� 8���49� 5 .85. �� ���� �/� 5� /�5� 8�45/���� ! �&� &/ � 5�5/���� �����;��� .� ' �/a �+.k/;. �*� -����� /���:�/3���%�@/4. ���������� ��44�2d��2�� j�����'���j�������&���/���������&�/�����(��h;.��������! 9 /����/8���8 � �85� / 5/8 ����� /� �9/���� 5�8 �/i.� �>/5 �'*$�*/8��� $���� � -��5 ��6� 5 ��'9 5�-��6�*/8�� $�5�� /6/8�5/����! �8�� $�5��� ���6��'��9���� /�����4 /�������������44����������� j/���9��*����� ���� '�����)��5 �� �d�d��� �� i.��5/5�5/3�� ���5/�� /4� ;�5>����4���5� 4�4.��5/�� � ���� 8 �4�9/�������3���� ���������,��2���� h�-����'��+��)���dd����. ��5� 5�5. �����4 � 4�85 �6� � �/�6���6����� �/��4 ��.85/���/���������� �� �������� �*/8��*� ��$� 5��!.;��#���<��4�<��� h��� ��+��*���������+/ �� /���dd,��!���5�4�4.��5/�������4���5/���4�55� ���66�85 ����9/��������9/���� 8�-4����5 ��6� /8��� 9@�� �5/3��"���/��$ 6� ��������� /���'8/��#�5��*� �. ��������������� critical period of weed competition in transplant aus rice cv bangladesh agron. j. 2014, 17(1): 95-102 critical period of weed competition in transplant aus rice cv. brri dhan27 under non-saline agro-ecosystem m. t. rahman, s. ahmed, n. j. lipi, m. h. rashid and m. i. hoque1 department of agronomy, patuakhali science and technology university, patuakhali, bangladesh, 1department of environmental science, bangladesh agricultural university, mymensingh, bangladesh corresponding author: trahman302@gmail.com key words: critical period, weed competition, transplant aus, brri dhan27 abstract a study was conducted to determine the critical period of weed competition in transplant aus rice for var. brri dhan27. among the treatments, weed free condition, competition of weed for first 10, 20, 30, 40, 50, 60 and 70 days and weed free later on, unweeded condition, one weeding at 20 days after transplanting and one weeding at 40 days after transplanting, the unweeded control plots showed the poor performance result in case of maximum parameters where grain yield was reduced the highest percentage (38.54%). on the basis of cost benefit ratio it was observed that the critical period of crop weed competition extended up to 30 days after transplanting of aus var. brri dhan27. introduction rice is one of the most important staple foods for more than half of the world’s population (irri, 2006) and influences the livelihoods and economies of several billion people. in asia, more than 80% of the people live on rice, and their primary food security is entirely dependent on the volume of rice produced in this part of the world (kabir, 2006). it is estimated that 40% of more rice production will be required by 2030 to satisfy growing demand with no increases in cropping areas (khush, 2005). weeds are at present the major biotic constraint to increase rice production world wide (zhang, 1996). about 33% of this loses are caused due to weeds alone (mukherjee and singh, 2005). the yield losses due to uncontrolled weed growth in lowland and upland rice ranged from 12 to 81% (chopra and chopra, 2003; mukherjee and singh, 2005). normally the loss in rice yield ranges between 15-20% yet in severe cases the yield losses can be more than 50% depending upon the species and intensity of weeds (brri, 2006). to develop a comprehensive control program for the weed, it is important to know its critical period of competition in transplant rice. the critical period of weed competition depends on several factors like species of weed, life time duration of crops, climatic factors, crop species, environmental factors etc. critical period of weed control is an integral part of integrated weed management (iwm) and can be considered the first step to design weed control strategy (anonymous, 2003). in general critical period of crop weed competition is throughout in direct seeding situation and in transplanted it vary from 15 to 45 days (singh and bhan, 1988). the most critical period for competition between rice and weeds is when the rice is in the vegetative phase and the yield components of rice are being differentiated (mukherjee and singh, 2003). though critical period of weed–crop competition is an important component of weed management technology package for any crop but for aus variety brri dhan27 it has not been investigated to find out the critical period of weed competition in transplant aus rice cv. brri dhan27. materials and methods 96 rahman et al. the study was conducted at the field laboratory of the department of agronomy, patuakhali science and technology university, patuakhali during the period of april to august 2012. geographically, the patuakhali science and technology university is situated at 20°20″ n latitude and 90°20″ e longitude. it belongs to the agro ecological zone (aez)-13 named ganges tidal flood plain. the experimental site was about 1.5 m above the sea level. the field of the experimental site was characterized by non calcareous grey floodplain soil with silty clays. it was well drained and medium high. the soil was mildly alkaline, non-saline, loam in texture and having soil ph ranges from 5.50 to 6.50. organic matter content was low (1.1%) (srdi, 2005). the experiment was laid out in a randomized complete block design with three replications and eleven treatments as: t1 = weed free condition, t2 = competition of weed for first 10 days and weed free later on, t3 = competition of weed for first 20 days and weed free later on, t4 = competition of weed for first 30 days and weed free later on, t5 = competition of weed for first 40 days and weed free later on, t6 = competition of weed for first 50 days and weed free later on, t7 = competition of weed for first 60 days and weed free later on, t8 = competition of weed for first 70 days and weed free later on, t9 = unweeded condition, t10 = one weeding at 20 days after transplanting (dat) and t11 = one weeding at 40 dat. the area of a unit plot was 4 m × 2.5 m. the sprouted seeds were sown in the prepared seed beds on 5th april, 2012. the seedlings were transplanted in the main field @ 2 seedlings hill-1 with 20cm × 15 cm spacing on 30th april, 2012. fertilizers were applied @ 168 g urea, 60 g tsp, 30 g mop, 17 g gypsum and 5 g znso4 to the plots. the whole amount of fertilizers except n was applied before final land preparation. urea was top dressed @ 56 g in three equal splits at 15, 30 and 45 days after transplanting. proper crop protection measures were taken during the entire course of crop production. weeds were collected at every 10 days interval according to the treatments mentioned. number of weed plant of each species in the unit plot was counted with the help of a plant counter. the intensity of infestation of each species of weed was calculated as the number of weed stands per unit area divided by the number of hills per unit area. three weed sample plot1 were collected at the time of weeding. the plant counter was placed at random in the unit plot and all the weeds within each 1 m2 were uprooted, dried first in the sun and thereafter, 24 hours in an electric oven maintaining a constant 1050 c. after drying weeds weight of each sample was measured and expressed in g m-2. three weed sample plot-1 were collected at the time of harvesting. the crop of all plots was harvested on 3 july 2012. crop and yield contributing were also recorded. results and discussion seven species of weeds under four different families were found in the experimental field. three species belonged to the family cyperaceae, two from gramineae and one from each of onagraceae and pontederiaceae (table 1). among those weed species, cyperus difformis l., jussiaea decurrens (watt.) dc. cynodon dactylon (l.) pers. were predominated, and constituted about 84% of the total weed vegetation. only cyperus difformis l. constituted 63.82 percent of total weed infestation and it was followed by jussiaea decurrens (watt.) dc. (11.40 percent). in total 14.26 weeds competed against one hill of rice of which 10.16 belonged to the family cyperaceae, 1.88 belonged to the gramineae family and rest small portion was belonging to other two family. thirteen types of weeds were found in direct seeded and transplanted aus rice as affected by method of planting and weeding regime by sarker et al. (2002). individually the highest intensity of weed infestation (9.09 hill-1) was recorded in cyperus difformis l. fimbristylis miliacea (l.) vahl. showed the lowest intensity and numerically it was only 0.38 weeds hill-1. jussiaea decurrens (watt.) dc. and cynodon dactylon (l.) pers. was produced in an intensity of 1.63 and 1.22 weeds hill-1. in case of weed population per square meter space total 456 weeds were found m-2 and the highest and lowest number of weeds belonged to the family cyperus difformis l. and fimbristylis miliacea (l.) vahl. respectively as percent of total weed vegetation and intensity of weed infestation at weeding. in a study ahmed et al. (1986) found that the principal weeds were monochlora vaginalis, scirpus mucrontus and cyperus iria in case of br3 cultivation in aus season. in another study in case of direct seeded upland rice cultivation cyperus rotundus and echinochloa crusgalli 97 critical period of weed competition in transplant aus rice was the principal weed (mamun et al., 1986). mercado (1979) found that competition of echinochloa crusgalli was found to be the highest at a density of 20 plants m-2 within the critical period of crop-weed competition. this difference might be due to climatic change, varietal change and other cultural management. table 1. infested weed species and their population in transplant aus rice cv. brri dhan27 name of weeds family weed populatio n m-2 % of total weed intensity of weed (hill-1) local name english name scientific name sobuj nakful green flatsedge cyperus difformis l. cyperaceae 291 63.82 9.09 pani morich winged water primorse jussiaea decurrens (watt.) dc. onagraceae 52 11.40 1.63 durba bermuda grass cynodon dactylon (l.) pers. gramineae 39 8.55 1.22 chechra bog bulrush scirpus mucronatus l. cyperaceae 22 4.82 0.69 chela sheand grass parapholis incurve l. gramineae 21 4.61 0.66 soto panikochu pickerel weed monochria vaginalis (burm. f.) presl. potedariaceae 19 4.17 0.59 joina globe fringerush fimbristylis miliacea (l.) vahl. cyperaceae 12 2.63 0.38 the weed population increased gradually from the competition of weed for first 10 to 60 days and weed free later on. the highest (598.00) weed population was found in t7 (competition of weed for first 60 days and weed free later on) and the lowest one (77.00) was found in t2 ( for first 10 days and weed free later on). during harvesting time no weed was found in the experimental plot as the plots were kept weed free after every weeding treatment (table 2). the highest (498.30) number of weeds were found in the plots which were kept unweeded (t9) and the lowest (288.70) was found in t11 (one weeding at 40 dat). all the treatments had significant effect on weeds dry weight m-2 at weeding. treatment t7 produced the highest (254.20 g) weeds dry weight at weeding whereas t2 produced the lowest (6.54 g). the treatments t9 and t10 gave the highest (204.20 g) and the lowest (144.30 g) dry weight of weeds. similar result was found by sarker et al. (2002). on average 33.8% weed dry weight was reduced due to competition from aus rice (karim, 2000). table 2. effect of duration of weed competition on the population and dry matter production of weeds in cultivation of transplant aus rice cv. brri dhan27 treatments weeds population (m-2) weeds dry weight (m-2) at weeding at harvest at weeding at harvest t1 0.00j 0.00d 0.00 i 0.00d t2 77.00 i 0.00d 6.54h 0.00d t3 152.00h 0.00d 7.69h 0.00d t4 218.00g 0.00d 51.84f 0.00d t5 361.00d 0.00d 147.30e 0.00d 98 rahman et al. t6 415.00b 0.00d 168.60b 0.00 d t7 598.00a 0.00d 254.20a 0.00d t8 398.00c 0.00d 162.90c 0.00d t9 0.00 j 498.30a 0.00 i 204.20a t10 287.00f 311.70b 48.31g 144.30c t11 332.00e 288.70c 158.40d 165.20b lsd(0.05) 0.69 1.55 3.19 2.94 different treatments had significant effect on the plant height of transplant aus rice cv. brri dhan27. numerically the plots which were kept weed free for whole the cultivation period (t1) gave the highest (138.8 cm) plant height and it was followed (136.1 cm) by 10 days for weed competition. on the other hand, the plots which were allowed for competition of weed for first 60 and 70 days; and the plots which were weeded only once at 40 days after transplanting (dat) gave the lower plant height than others (fig. 1). perera et al. (1992) and sultana (2000) also found similar reduction on rice plant height due to competition of e. crusgalli. fig. 1. effect of duration of weed competition on plant height of transplant aus rice cv. brri dhan27 (lsd(0.05) = 4.67) all the plots except those were kept unweeded (t9) for the entire cultivation period showed statistically at par in terms of panicle length. treatments t1 to t4 produced higher panicle length than others where the longest (24.14 cm) panicle was produced where kept weed free throughout the cropping period (t1). the plots in which first weeding were done after 40, 50, 60 and 70 days after transplanting and unweeded throughout the cropping period gave lower number of total tillers than others (table 3). table 3. effect of duration of weed competition on the yield contributing characters of transplant aus rice cv. brri dhan27 treatments panicle length (cm) total tillers hill-1 (no.) filled grains panicle-1 (no.) unfilled grains panicle-1 (no.) 1000-grain weight (g) t1 24.14a 11.09a 108.0a 16.72a 31.55a t2 23.90ab 10.75a 104.7ab 14.46b 31.55a t3 23.77abc 10.82a 101.4bc 10.56d 31.58a t4 23.10bcd 9.557b 98.13c 14.60b 31.22ab t5 22.84cde 8.837c 98.54c 9.493e 31.54a t6 22.61def 8.820c 92.11d 16.49a 31.00abc 99 critical period of weed competition in transplant aus rice t7 22.24def 8.297cd 84.40e 10.46d 30.77bcd t8 21.65f 8.543cd 78.31f 12.25c 30.46cd t9 19.14g 8.003d 74.42g 14.26b 30.15d t10 22.04ef 9.647b 84.84e 7.710f 30.73bcd t11 21.90ef 9.650b 86.75e 14.60b 30.53cd lsd(0.05) 1.01 0.65 3.56 0.64 0.66 the plots which were kept weed free throughout the whole cultivation period, and the plots in which first weeding were done at 10, 20, and 30 dat i.e. t1 to t4 gave statistically higher number (9.865–10.37) of effective tillers (fig. 2). fig. 2. effect of critical period of rice weeds competition on effective tillers hill1 of transplant aus rice cv. brri dhan27 (lsd(0.05) = 0.80) the highest (108.00) number of filled grains panicle-1 was recorded from the plots which were kept weed free for the total cropping duration. plots which were weeded for the first time at 20 dat and kept weed free for later on (t3) showed the highest 1000grain weight (31.58 g). the plots which were weeded only once at 20 and 40 dat (t10 and t11) showed similar effect (3.29 and 3. 28 t ha-1) in terms of grain yield of brri dhan27. percent grain yield reduction was increased with the increasing of weed competition period and it reached to the highest as 34.54% in unweeded control plots. in case of one weeding, weeding at 20 and 40 days after transplanting reduced the grain yield of about 17% of that of the weeded control plots. weed free plots and the plots in which the competition of weed were allowed for first 10, 20, 30 days and kept weed free for later on gave higher yield than others. grain yield of t. aus rice cv. brri dhan27 was significantly affected by the treatments of weeding. the plots which were kept weed free from transplanting to harvesting gave the highest (3.97 t ha-1) grain yield and it was followed (3.94 t ha-1) by t2 .the unwedded plots gave the lowest (2.44 t ha-1) yield and it was followed by treatments (table 4). when weed infestation is increased, the rice plants deprive from nutrient and other environmental components. as a result, the long time weed infested plot showed lower performance than short time weed infestation. table 4. effect of duration of weed competition on the yield of transplant aus rice cv. brri dhan27 treatments grain yield straw yield t ha-1 % reduction t ha-1 % reduction t1 3.97 a 3.22 ab t2 3.94 a 0.76 3.36 a -4.25 100 rahman et al. t3 3.90 a 1.76 3.22 ab 0.00 t4 3.89 ab 2.02 3.09 ab 4.04 t5 3.76 b 5.29 2.86 bc 11.18 t6 3.50 c 11.84 2.65 cd 17.70 t7 3.05 e 23.17 2.53 cd 21.43 t8 2.49 f 37.28 2.34 d 27.33 t9 2.44 f 38.54 2.42 d 24.84 t10 3.29 d 17.13 2.65 cd 17.70 t11 3.28 d 17.38 2.57 cd 20.19 lsd(0.05) 0.13 0.42 weed population and their dry weight was increasing with the increasing of weed competition duration and weed removal delayed up to 60 days after transplanting and decreased thereafter. it might be due to death of some older weeds and thinning of newly germinated weeds. unweeded control plots showed the poor result in case of maximum parameter where the grain yield reduced in the highest percentage (38.54%). in case of grain and straw yield the plots which were allowed for 10 days weed competition (t2) showed the highest performance. treatment t2 gave better plant height (136.1), panicle length (23.90) and effective tillers hill-1 (10.13). on the other hand the plots in which competition of weed was allowed for first 20 days showed better performance in terms of total tillers hill-1 (10.82). in case of grain yield t1 (control), t2 (competition of weed for 10 days), t3 (competition of weed for 20 days) and t4 (competition of weed for 30 days) gave same and higher (3.89 – 3. 97 t ha-1) yield than others. conclusion the result obtained from the study showed that the percentage of grain yield reduction with the increasing of crop weed competition was negligible up to 30 days competition. so, crop weed competition for first 30 days could be a critical period in transplant aus rice cv. brri dhan27. references ahmed, s., a. mamun, a. m. a. islam and s. m. a. hossain. 1986. critical period of weed competition in transplanted aus rice. agric. rev. 27: 247257. ahmed, s. and a. majid. 1977. effect of weed control duration on paddy yield of different varieties. j. agric. res. 15: 293-298. anonymous. 2003. principles of weed management. international rice research institute, p.o. box.983. manila, philippines. p.113. baloch, m. s., i. u. awan, s. a. jatoi, i. hussain and b. u. khan. 2000. evaluation of seeding densities in broadcast wet seeded rice. j. pure appl. sci. 19: 63-65. brri (bangladesh rice research institute). 2006. weed identification and management in rice. bangladesh rice res. inst. joydebpur, gazipur, bangladesh. pp.101-113. burnside, o. c., m. l. wiens, b. j. holder, s. weisberg, e. a. ristau, m. m. johnson and j. h. cameron. 1998. critical period for weed control in dry beans (phaseolus vulgaris). weed sci. 46: 301-306. chopra, n. k. and n. chopra. 2003. weed management strategy in rice a review. indian j. weed sci. 35: 27-29. 101 critical period of weed competition in transplant aus rice garrity, d. p., m. morillion and k. moody. 1992. differential weed suppression ability in upland rice cultivars. agron. j. 84: 586-591. irri (international rice research institute). 2006. bringing hope, improving lives: strategic plan 2007–2015. manila, philippines. p.61. jennings, p. r. and r. c. aquino. 1968. studies on weed competition in rice. ii. the mechanism of competition among phenotypes. evolution. 22: 529-542. johnson, d. e. 2002. weed management in small holder rice production in the tropics. chatham, kent, uk: natural resources institute, university of greenwich. kabir, h. 2006. adaptation and adoption of the system of rice intensification in myanmar using the farmer field school (ffs) approach. available: http://ciifad.cornell.edu/sri/theses/kabirthesis. pdf. karim, s. m. r. 2000. competitive ability of three grass weeds grown in upland direct-seeded rice in bangladesh. pakistan j. agric. res. 16: 24-27. khush, g. s. 2005. what it will take to feed 5.0 billion rice consumers in 2030. plant mol. biol. 59: 1-6. mamun, a. a., s. ahmad and a. u. sarker. 1986. critical period of crop weed competition in direct-seeded aus rice. bangladesh j. agric. sci. 13: 61-66. mercado, b. l. 1979. introduction to weed science. southeast asian regional center for graduate study and research in agriculture, laguna, philippines. p.292. mukherjee, d. and r. p. singh. 2003. in: proc. biennial conf. of indian soc. weed sci. held at pant nagar from 12-14, march, p.11. mukherjee, d. and r. p. singh. 2005. weed management strategy in rice. indian j. agron. 50: 194-196. perera, k. k., p. g. ayres and h. p. m. gunasena. 1992. root growth and the relative importance of root and shoot competition in the interactions between rice (oryza sativa) and e. crusgalli. weed res. 32: 6776. sarker, m. y., m. m, hossain, m. k. hasan, m. a. h. khan, m. r. amin and f. begum. 2002. weed infestation in direct seeded and transplanted aus rice as affected by method of planting and weeding regime. j. biol. sci. 2: 652-655. singh, o. p. and v. m. bhan. 1988. chemical weed control in lowland transplanted rice under puddle condition. indian j. weed sci. 18: 244-249. srdi (soil resource development institute). 2005. upozilla nirdeshika: dumki (in bengali). 2nd edn. dhaka, bangladesh. pp.7-87. sultana, r. 2000. competitive ability of wet seeded boro rice against e. crusgalli and e. colonum. m. s. thesis bau, mymensingh, bangladesh. pp. 36-50. zhang, ze-pu. 1996. weed management in transplanted rice. in: b. a. auld and k. u. kim (eds.) weed management in rice. fao plant production and protection paper 139. food and agriculture organization of the united nations, rome, italy. http://ciifad.cornell.edu/sri/theses/kabirthesis http://ascidatabase.com/author.php?author=m.y.%20sarker&last= http://ascidatabase.com/author.php?author=m.%20mosaddeque%20hossain&last= http://ascidatabase.com/author.php?author=m.k.%20hasan&last= http://ascidatabase.com/author.php?author=m.a.h.%20khan&last= http://ascidatabase.com/author.php?author=m.r.%20amin&last= http://ascidatabase.com/author.php?author=f.%20begum&last= microsoft word final.doc � �������� ��� �������������������������� ��� !"�#�"��$�"%&$! %!" �'(���")($*!%��%�+!((&$&,%���� !"�#�"��$�"%&$! %!" �'(���")($*!%��%�+!((&$&,%���� !"�#�"��$�"%&$! %!" �'(���")($*!%��%�+!((&$&,%���� !"�#�"��$�"%&$! %!" �'(���")($*!%��%�+!((&$&,%� ��$-& %!,.�%!/& ��$-& %!,.�%!/& ��$-& %!,.�%!/& ��$-& %!,.�%!/& ���� ���� !�����! 0�!�����! 0�!�����! 0�!�����! 0�������/�������12���/�������12���/�������12���/�������12�������������/��.��$�33��0/��.��$�33��0/��.��$�33��0/��.��$�33��0���������������)���0 4� �������)���0 4� �������)���0 4� �������)���0 4� 5555���� �� 0 6��6�% ����&�27�60���'8807� ��/�609 �����+ �:��� �� �8� � ��+�;� 6<��6��8��� 6072�62 ����*��/=<�� 0�� �� 5� �8� � ��+�;� 6<��6��8��� ���<=�� �*��+ �:�� "� � ;���0����26 � ��0 �6�6��>�<�0��7�<� )�=�4� � �)�=�4� � �)�=�4� � �)�=�4� � ��� = 07���7 � �76� 0 607 �� � ?� 60���60<���9�7:8 206� � � �3 6 �76�3 6 �76�3 6 �76�3 6 �76���� ���� ��� �@;� 0<��6� 4� � 7���276��� �6� 6 �� ��7:8 206� $� �� 7 � � �9�76�� �� 6072�62 �� 8� <� �8� �������� ��� 072�62 ���*�0?� 06=��/=<�� 0�� ��2 0���6 ��;� 0���8 �<�+�7�<3� ������ 6���2�=����5�406 �6 ���39�760?� �6����6� <0���6 ��; = 07���7 � �76� 0 607 ��8�6 ���6=;� � �8� 9�7:8 206� �6� �088� ��6� � ?� 60��� 60<�� ?0 � �� ?0 � � �;; �; 0�6�� 60<�� �8� � ?� 6� �8� 6 �<�� � = 07��� 7 � �76� 0 607 ��8� 6 ��� 6=;� � 0��07�6��� 6 �6� 32�3�4�0� 6� �a����7 �� ������� 0��� 4�0� 6��a��0�7 �� ����6���6� � 6��� ��8� � ?� 60����% ��32�3��8�. 0���4� �?� =� �86��6��� �=� � ?� 60��� 6���� 326� 80 <� �6� ��6�� � ?� 60���� % �� ��03��� ;� 60��� 4� � 8�2��� 6�� 3�� 6 �� 0� � 6��b���ba��0��<0�� � ?� 60���60<������+� � ��6=;����?��6 ��<�@0<2<��bb���a��� % �� 8 206 � �8� ��6�� � ?� 60��� 60<�� ��� ?0?0;� �2 � ����� &� �=� ����<0�� � ?� 60��� 60<� � 4� ��8�2���6��3��3�66� �0������6 ���6=;� ��8���7:8 206�����. 0���4� �8�2���6��3�� 2;� 0� �� � � !�6 ��2760��!�6 ��2760��!�6 ��2760��!�6 ��2760������ � ��7:8 206� �� 6�7� ;�2 � �6� �; =���2 �#�<��� 0 � 6 ����60����� 8 206��8��������� ��% ��; ��2760��� �8� 9�7:8 206� 0���������� �4� � ��c����b� 6�� � 8 �<� ��� � ��� �8� cc��cb� �76� � � ��� �� ���5��� ��7:8 206�<�=�7��6 0326��6��6 ���26 060����8�6 ��;��;���� ��� �2 7���8�<0�� �� ��?06�<0� ��7��702<�� 0 ���� � �"� �6����� 6 0�<0������� 2�� ��67��*� 0;�� 9�7:8 206� � ��� �<� :�3�=� 0<0�� � 6�@62 �� 6�� 7 07:���� <�:0��� 9�7:8 206� ��� �@7�����6� ?���6� 0��� 23 60626�� 8� � <��6�� !�� 8�76�� 9�7:8 206� 0 � �<�60<� � �8� ��� 6�� � � d?���6�3��� <��6e�� )�<��2��0�� ���cc�� �;� 6��� 6 �6�� 3�0��� 7 � � ;���0��6�������<� 6�=� ����; �;���6���6 �� 9�7:8 206� � � 0��2<� �3��� 6=;� �7�� 0�� 0���6 ��8 206� 7 � �76� 0 607 ��088� 0���0����� 06=��8� ;0:� ����6 �� 0����3�� 0��� �306�� 0f��� �;���120�06=��8�8 206� ����;� 0����8�<�62 06=����12������5��0���6080���6 ���6=;� ��8�9�7:8 206� 27 �� �) �9���. 0������� +� � �������=<�2 � ������� 0���6080��� 6 �6� 6 �� 6�@62 ���8� 32�3� 3�7�<�� 7 0 ;=�4 ��� 6 �� 8 206 � � ?� 6��� 0�� ��6� � ;� 6� �8� �� ���� ����=<�2 � ������� 4� :��� 406 � ; = 07�� 7 �<07��� 7 � �76� 0 607 � �8� . 0��� 6=;�� �6� 6 ��� �088� ��6� � ?� 60��� 60<� � ���� �;� 6��� 6 �6� ; = 07��� 7 � �76� 0 607 � 27 �� �4�0� 6��8�8 206��32�3�� ���� �7 0 �� 0�������6 �0 �;� 7��6����4� ��?� 0����6� �088� ��6� � ?� 60��� 60<��� -0?0;� 06=� 4� �� 8�2��� 0� � 6� 0�� ��6�� � ?� 60��� ��f���� ������� &� �=� � ?� 60��� 60<�� ��� ��� ?0?0;� �2 � ����� ��12�� ����5�� �;� 6��� 6 �6� 6 �� ;� 7��6���� �8� 0��� 0�7 �� ���406 �����=��8� � ?� 60����4 0���32�3�;� 7��6���� �4���6 �� �?� ��6 ���������=<�2 � ����b�� 8�2���. 0��� 7��6�0�� 0� � 6� �2<3� � �8� 32�3� ;� � 8 206� ���� 0��� ;� 7��6� 4� � 0� � 6� 0�� ) �9���% � �8� ��6 ��; � ��6�6 0���4� �2��� 6�:���6��80����26�6 ���;; �; 0�6��60<���8� � ?� 60��� 8� �6 ���6=;� �����; = 07���7 � �76� 0 607 ��8�9�7:8 206��6��088� ��6� � ?� 60����� � ��� ! 0���6����� /�6� 0�� �/�6� 0�� �/�6� 0�� �/�6� 0�� ��������/�6 �� ���/�6 �� ���/�6 �� ���/�6 �� ���� � % ���@;� 0<��6�4� �7� 0����26�8 �<������6���2�=����5��% ���6=;� ��8�9�7:8 206�4� �� ���76��� 8 �<���7:8 206�$� �� 7 �� �9�76��6� 6 ���� 6072�62 ��(� <��8��������� ��� 072�62 ���*�0?� 06=�� /=<�� 0�� �� % �� ���76��� ;���6 � 4� �� 6 ��� 6=;� � ��<��=� ) �9��� . 0��� ���� +� � �� ���� � ?� 6��� �6� �088� ��6� 60<� � ��<��=� �� �=� � ?� 60���� <0�� � ?� 60��� ���� ��6�� � ?� 60���� % �� ���76���;���6 � �?��3����� �4�����<��02<� 0� �������8������ � <�;26 ��8�����;��0�� �0��6 �76� �8� �������� �� % �� �0�� 4� � ���=� ���<=� �?0��� ;�� c�c�� % �� 62�=� 4� � 7���276��� 0�� �� ����<0f��� 7�<;��6�� 3��7:� �� 0���406 � 6 ��� �;�07�60�� �� %0<�� ���� 6=;� � � ?��� � � �088� ��6� 8�76� ��% 2 �6 � ��4� ��6 ���60<� ��8� � ?� 60�������6 ���6=;� ��8�9�7:8 206��/�62 ��9�7:8 206 � 4� ��7����76��� 8 �<� 6 ��;���6�����:�;6��6� �<30��6� 6�<;� �62 �� 8� � 82 6 � � 62�=������= 0 �4� � ����� 0�� 6 �� ��3� �6� =��8� 6 ��+�;� 6<��6��8�(����%�7 �����=�����$2 ��� !��2 6 =���������� � �� 072�62 ���*�0?� 06=��/=��� 0�� ���=�2 0����088� ��6�;� �<�6� �; = 07���7 � �76� 0 607 �4� �� 62�0����% ��7����76�����6��4� ������=f��� 6�60 607���=�������92 6���406 ���� 6� 0��0807��6��088� ��7�� 6� 6��# +���6�ba������a���?����8�; �3�30�06=�� ���� $� 2�6�$� 2�6�$� 2�6�$� 2�6��������+0 72 0�����+0 72 0�����+0 72 0�����+0 72 0������ ���� % �� � 2�6����6 �� 62�=��8� 0f�������6 �@�40�6 �@�70 72<; � ��7���� �;������4�0� 6��8�6 ��6 ��� 6=;� � 9�7:8 206� �6��088� ��6� � ?� 60��� 60<� �� �� �4�� 0��%�3�� �����������<���� 6 ���088� ��6� � ?� 60��� 60<� �� <0�� � ?� 60��� 8 206� ��?�� <�@0<2<� �?� ���� 8 206� ����6 � �bb�c�7<� @� 40��� 5���b7<�@� 70 72<8� ��7�� �5���7<��4 0��� 06�4� �<0�0<2<��6� �� �=� � ?� 60��� ����) �9�� 6=;�� ��?�� <�@0<2<� 8 206� 4�0� 6� ������:��� �6� <0�� � ?� 60��� 4 0��� <0�0<2<� ����5�:��� �6� �� �=� � ?� 60��� 0��+� � ���% �� 0� � 6� 0f��4� �b5���7<�������7<����������7<��36�0���� 8 �<� . 0���8����4���3=�+� � ������) �9���% ��; � ��6� � 2�6�4� ��7�� ��6��6 ��80��0�� ��8�� �60���6� ���� ���bb������/�4 =� � ���b5��4 �� �;� 6��� 6 �6� 6 �� 8 206 � 6��3�����5�� 6�������7<� ��������� �b����6��b����7<�40������ �0��������12��������� 6�6���6 �6�6 ��<��������6 ������0�<�6� ��8� 8 206 � 4� �� 5��c� ���� ����7<�� % �� 0�6� �760��� �88�76� ��� 0��0807��6� � ;�� ��� /�4 =� ���b5�� <��60�����6 �6��?� ����4�0� 6��8�8 206� ���� �8 �<���b��:��6�������:��� % �� � ;�� �� 8� � �� � � 4�0� 6� �8� 8 206 � �6� 6 �� ��6�� �� ��� <0� 6� 3�� �2�� 6�� ��7:� �8� ���12�6�� 2;;�=��8��26 0��6 � 0�7��;���6 �<0� 6�3���@ �2 6����8�6 �0 �8����3�7�2 ���8���?���;<��6��8��� �=� �� ��� 8 206 �� ����=<�2 � �������4 �� �;� 6��� 6 �6� 8 206 � �8�<0�� � ?� 60��� 60<��4� �� �� �� � 4 0���6 � ��0����6�� �� ���4� �� <���� �� � % �� 0� � 6��2<3� � ���c������8�32�3 �4� ��36�0���� 8 �<��� �=� � ?� 60��� 60<�� 0��. 0��� ������� 4 0��� 06�4� �<0�0<2<� ����������6� ��6�� � ?� 60��� 0��) �9�� ��b��� �%�3�������������% ��; � ��6� � 2�6� � � 0<0�� 06=�406 ��� �0��������12����������% �=�8�2���6 �6�6 ���2<3� ��8�32�3�?� 0��� 8 �<�5��6����b��% �� 0f���8�32�3�4� �8�2���6 �� 0� � 6� �����7<�@�����7<���6�<0�� � ?� 60��� 60<��4 0��� 06�4� �<0�0<2<� �b���7<�@�5�5�7<���6� �� �=� � ?� 60��� �%�3�������% ��� ��6� �32�3� ����6 � ���� �0�<�6� � 4� � 8�2��� 0�� ) �9�� �c��c7<� @� ��5�7<�� 7�<;� ��� 6�� . 0��� �b�c�7<� @� 5��c7<���� �60���6��������bb�� �;� 6���6 �6�6 ��32�3� 0f��0 ����b��6��c�5b7<�@���c��6��5���7<�� �� �0��������12��������� �;� 6���6 �6�6 �� 0f���8�32�3�4� ������6����b7<�@���c��6��b��7<��� � � � � = 07 �� �" � � 76 � 0 607 � �8 �� �7 :8 2 06� � % �3 �� �� �� / �0 �� �8 8� 76 �� 8� � ? � 60� �� 60< �� �� �6 � �; = 0 7� ��7 � � 76 � 0 607 � �8 �9� 7: 8 20 6� � � ?� 6 0� �� 60< �� ( 20 6� 0f �� �7 < �� ( 20 6� 4 6�� :� � � 2� 3� 0 f� � �# �@ �+ �� 4 6�� �8 �� �� �� �0 3� �� ;� 6 0� �� �: �� � 4 6� �� 8�� �0 3� �� ;� 6 0� �� �: �� � a �� 2� 3� a �$ 0� �� a � �� �� a � 0? 0; � �2 � a � $ �7 0 � , �� �� 8� 32 �3 �; � � 8 20 6� , �� �� 8� � �� � ;� � 8 20 6� # �� �6 � g 0� 6 � " 0 7 2< 8� � �7 �� $ 0� �� $ �7 0 � � 2� 3� �� �� & � �= � � 5� �� � � �� �� � � �� �� � � �� b� � b �� � �@ �5 �5 �� � �b �� � �� �� � �� �� � �5 �� � �� 5� � 5 �� �� � � �� 5� � � �� �� � �� �� � �c �� � � 5� / 0� � b b� c� � 5 �� �b � � c� �c � � b� �c � � �� �@ �� �� �� � �� c� � �5 �� � �� �� � �� �� b �� �� � 5 �� 5� � � �� �� � �� �� � �c �� � bb �� � � �c # �6 �� � �� �� � � �� c� � c �� �� � � 5� b5 � b �5 � �@ �5 �� �� c �5 5� � �� �� � �� �� � �� �� 5 c� 5� � � c� �� � � �� �� � �� �� � � �� �� � �� �� � � �� # + �b a � � �� �� � �c �� � �� �� � �� �� c �� � � �c c� � �� �� � �b b� � �� �� � �� �� � �� b� � �� �� � �� � � �� c� � �� 5� � �� � # + �� a � � �5 5� 5 �� �� c �� �� � �b �� � �� �� � �� �� � �� c� � �5 �� � �� c� c �b �� b �� �� c �b �� � �� �� � �5 �� � b� b� b �� � # �? �� �� 8� 0 �� 080 7� �7 �� hh � hh � hh � hh � hh � hh � hh � hh � hh � h� hh � hh � hh � hh � hh � hh � % �3 �� �� �� / �0 �� �8 8� 76 �� 8� 6= ;� �� �� 6 �� ; = 07 �� �7 � � 76 � 0 607 � �8 �9� 7: 8 20 6� % =; �� ( 20 6� 0f �� �7 < �� ( 20 6� 4 6� �: �� � 2� 3� 0 f� � �# �@ �+ �� g 6� �� 8� �� �� �� 03 �� �; � 60� �� �: �� � g 6� �� 8� �� 03 �� � ;� 6 0� �� �) �� � a � � 2� 3� a �$ � a � �� �� a � 0? 0; � �2 � a � $ �7 0 � , �� �� 8� 32 �3 �; � � 8 20 6� , �� �� 8� � �� � ;� � 8 20 6� # �� �6 � g 0� 6 � " 0 7 2< 8� � �7 �� $ 0� �� $ �7 0 � � 2� 3� �� �� ) � 9� � b �� �� � � �� �� � � �� �� � � �� �� � b �� � �@ �5 �5 �� c �5 �� � �5 �� b �� �� � �� �� 5 c� b� � � �� �b � � �� �� � �� 55 � � �� �� � b� �� � � �b �� � . 0 �� � b 5� �� � � �� �� � � �� �� � � 5� �� � � �� � �@ �� �� �� b �� �� � �� �� c �5 b� � �5 �� � b� c� � 5 c� �� � � �5 5� � �� �� � �� 5� � �� �� � � 5� �� � + � � � � � �� �� � � c� b5 � c �� �� � � �� 5� � b �5 � �@ �5 �� �� � �� 5� � �� c� b �� �� � �� �� � b� 5� � 5 �� �� � � �� �� � �� 55 � � �b �� � b� �� � � �5 �b � # + �b a � � �5 �� 5 �c �� � � �� �� � �c �� � �c c� � �� �� � �� b� � �� �� � �� �� � �� b� � �� �� � � �� b� � �� 5� � � �� � # + �� a � c �� b� 5 �� �� � � � �� �� � �� �� � �� c� � �5 �� � �� c� c �b �� b �� �� � �� �� � � �5 �� � b� b� � b �� � # �? �� �� 8� 0 �� 080 7� �7 �� hh � hh � hh � � hh � hh � hh � h� hh � h� hh � hh � � hh � hh � hh � % � �6 < �� 6 � g �0 � 6� �8 �8 2 06� ( 20 6� 0f �� �7 < �� , �� �8 � 32 �3 i � 8 20 6� g �0 � 6� �8 �3 2� 3 i� 8 20 6�� :� �� , �� �8 � � �� i � 8 20 6� g 6� �� 8� � 7 0 � �: �� g �0 � 6� �8 � � �� � �: �� � g 6� �� 8� � 7 0 � �: �� � g �0 � 6� �8 � 0� �� �: �� � � 2� 3� 0 f� � 0? 0; � �2 � �a �� � 2� 3� a � �� �� a � $ �7 0 � a � $ 0� �� a � �� �� 6 � g 0� �� 70 7 2< 8 � �� 7� � # �� �6 � �0 �< �6 � � & � �= � ) � 9� � � �� �� � � �� �� � � �� �� � c �� c� � � �� �� �� 5 �� 5� � 55 �5 5� � �� �� � �� �� b �� �� b �c �� 5 �� c� � �� �� 5 5� �� � � �� �� � � �� �� � b� �� . 0 �� � � �� �c � � �� 55 � � c� �� � � �� �� � � �b �c �� b �c �� � b� �5 5� � �� �� � �� c� 5 �� �� b �� �� 5 �c �� � �� �� � �� c� � � �� �� � � �� � 5 �� �c + � � � � � �� �� � � �� �� � � c� c� � c b� 55 � � �5 �c �� � �� �� � �� �5 5� � �� b� � �� �� � �� 5� � �� c� � �b 5� � �� �� � �� bc � � �� �c � � �5 � � �� c� / 0� � ) � 9� � � b� �� � b �� �� � � �� �� � � �� 55 � � �� �c �� c �c 5� � �� �c �� � �� c� � �� �� b �c c� � �b 5� � �� �� b �� �� � 5� �b � � �b c� � �� �5 5 c� �b . 0 �� � � b� �� c� c �� 55 � 5 �� �� � � �� 55 � � �� �c �� � �b �� � 5� �� �� � �� b� � �b �� � �� �� � �c �� � �� �� � �� �� b 5� �c � � �� �� � �� b � �� b� + � � � � � �� �� � � �� c� � 5 �� 55 � � �� c� � � �c �� �� � �� 5� � �� �� �� � �� �� � �� �� 5 �� �� c �� 5� b �� �� � �� 55 � b �� �� � � �� �� � �� b � �� �b # �6 �� ) � 9� � � b� �c � b 5� 55 � � 5� �� � c �� c� � � �� �� �� b �5 5� � �� �c �� � �� �� � �� �� � �� 5� c �c 5� � �5 �� b �� �� � 5 5� �� � � �� �� � �b � b �� �� . 0 �� � � �� �c � � �� c� � � c� 55 � � b� 55 � � c� �� �� � �� �� � �c �� �� � �� 5� � �� c� c �� �� 5 �� �� 5 �� 5� � �� c� � 5 �� b� � � �� 5� � �c b � �� �c + � � � � � �� �� � 5 �� c� � � �� c� � c �� c� � � 5c �5 5� � �b �� � �� �5 5� � �� �� � �� �� 5 �� c� b �5 �� 5 �� �� � �� c� � � �� �� � � �� c� � � �� 5� 5 c� �� # + � ba � � � �� �� � �c �� � �c c� � �� c� � �� c� � � �c b� � �5 b� � �� �� � �� �� � �� c� � �� �� � �� �� � b� b� � � �� �� � �� �� � �c b � �c b # + �� a � � � �c �� � �� �� � c �� �� � �� cb � � �� �� � � �� �� � �� �� � � �� �� � �� �� � �b �� � �c �� � �c c� � �� �� � � �� �� � � �� b� � �� � � �� 5b # �� �8 � 0� � � hh � hh � hh � hh � hh � hh � h� h� hh � hh � hh � hh � hh � hh � hh � hh � hh � ��� ! 0���6����� % �� 0��0807��6� 0�6� �760��� 3�64���� � ?� 60��� 60<�� ���� 6=;�� �8� 9�7:8 206� 0��07�6��� 6 �6� <0�� � ?� 60���60<��0��� �70�60���406 �) �9��6=;���@� 6���<�@0<2<��88�76�0��; ��270��� 0� � �32�3� ����6 ����c�7<������<0�0<2<��5���7<��406 �6 ��7�<30��60����8�+� � ��406 ��� �=� � ?� 60��� 60<���%�3���5���% �� � 2�6��8�32�3�4�0� 6�����4���6 �6�<0�� � ?� 60��� ���7�<;� �60?��=�� ��6� � 32�3� 4�0� 6� ���c�:��� 406 � . 0��� 6 ��� 6 �6� �8� ��6�� ���� �����:��� �%�3������ % �� 32�3� 4�0� 6� �8� 9�7:8 206� �� �� ?� 0��� �<���� 6 ��� 6=;� �� . 0��� 6=;�� ���<�@0<2<� 32�3� 4�0� 6� �c�5b:��� 4 0��� <0�0<2<�0��) �9�� �b���:���� ����4�0� 6��8� 9�7:8 206��6��088� ��6� � ?� 60���60<� �� �� �4��0�� %�3�� � ��� % ��<�@0<2<� ���� 4�0� 6� ���5:��� 4� � �36�0���� 8 �<� . 0��� ���� <0�0<2<� ����:��� 8 �<�) �9������0���� �=� � ?� 60���8 206���?��<�@0<2<����5�:����?� ���� ����4�0� 6�8����4���3=� ��6�� � ?� 60��� �����:�������<0�� � ?� 60��� 8 206� �����:����% �� 0�6� �760����88�76 ��8� � ?� 60��� 60<�� ���� 6=;�� 0�� � ;�76� �8� ����4�0� 6� 8�2��� 6�� 3�� 0��0807��6� �%�3��� 5��� % �� � 2�6 � ��� 6 �� �2<3� ��8� ��� �;� �8 206� �4���6 �6�6 ��. 0���; ��27���<�@0<2<��2<3� ��8� ��� ���5������ 8����4���3=�) �9�����b���������+� � �����5�b����% ���?� �����8��5��������c������������c�� ��� �;� �8 206�4� �8�2���0���� �=��<0��������6�� � ?� 60���60<� � � ;�760?��=��!�6� �760���3�64���� � ?� 60���60<� �����6=;��4� �8�2���6��3�� 0��0807��6��%�3���5��� ) �9��6=;��; ��27���<�@0<2<��?� ���� �7 0 �4�0� 6����5�:���4 0���06�4� �<0�0<2<�0��+� � �� ����c:����'��6 ���6 � � �����<0�� � ?� 60���60<�� ���<�@0<2<�4�0� 6��8� �7 0 ����b�:���4 07 � 4� � 0��0807��6�=� �088� ��6� 8 �<� ��6�� ����b:��������� �=� �����:��� � ?� 60����% ��; � ��6� � 2�6 � 4� �� 2;;� 6��� 3=� 6 �� 80��0�� � �8� ����=<�2 � ������� 4 �� �;� 6��� 6 �6� ) �9�� ; ��27��� <�@0<2<� �?� ���� �7 0 � 4�0� 6� 4 0��� 06� 4� � <0�0<2<� 0�� +� � ��� #�6�� � ?� 60��� 60<�� ; ��27���<�@0<2<��?� ���� 0���4�0� 6� �c�55:���4 07 �4� � 0��0807��6�=� �088� ��6� 8 �<��� �0� � ���� �%�3��� ���� % �� 4�0� 6� �8� 0��� �� �� ?� 0��� 0��0807��6�=� �<���� 6 ��� 6=;� �� ) �9�� ��� 6 �� <�@0<2<��?� ���� 0���4�0� 6��c�5�:���4 0���6 ��<0�0<2<�4� �8�2���0��+� � ������5:����% �� ; � ��6� � 2�6� 4� �� ?� =� 7�� �� 6�� 6 �� 80��0�� � �8� ����=<�2 � ����b�� 4 �� �;� 6��� 6 �6� : �9�� 7��6�0���� <�@0<2<� 4�0� 6� �8� 0��� ���� <0�0<2<� �36�0���� 8 �<� . 0���� ����=<�2 � ������� <��60����� 6 �6� <0�� � ?� 60��� ; ��27��� 5���:�� �8� 0��� 4 0��� 06� 4� � ��5�:�� �6� 6 �� �� �=� � ?� 60��� 60<��� % �� 0�6� �760��� �88�76� 3�64���� � ?� 60��� 60<�� ���� 6=;�� �� �� 8�2��� 6�� 3�� 0��0807��6���� ?� 60���60<�� ��� 0��0807��6� 0�8�2��7�����6 ��;� 7��6�����8�?0?0;� �2 � �����% �� <�@0<2<� �2<3� � �8� ?0?0;� �2 � ���� ������a�� 4� � 8�2��� 3=� ��6�� � ?� 60��� 60<�� 4 0��� �� �=� � ?� 60��� 60<�� ��� ��� ?0?0;� �2 � ���� �%�3��� 5��� ) �9�� ���� +� � �� ; ��27��� <�@0<2<� �?� ���� ?0?0;� �2 � ��� � ����55a�� 4 0��� 06� 4� � <0�0<2<� 0�� . 0��� �%�3��� ���� % �� � 2�6 � 2;;� 6��� 3=� 6 �� 80��0�� ��8���303� ����5�� �����f��� ������������=<�2 � ������� �;� 6��� 6 �� <�@0<2<�;� 7��6�����8�?0?0;� �2 � ����4� ��36�0����3=���6�� � ?� 60����! ��<�����5���3 � ?��� 6 �6� : �9�� 7��6�0�� 5��ba� ?0?0;� �2 � ���� 4 � �� � � . 0��� 7��6�0�� ���=� ��a�� % �� 0�6� �760��� �88�76�3�64���� � ?� 60���60<������6=;� ��� ��8�2��� 0��0807��6� � ;�� ��� % �� 32�3� ;� 7��6����4� � 8�2��� 6 �� 0� � 6� �b����a�� �6�<0�� � ?� 60��� 60<�� 8����4��� 3=� ��6�� �5c�5�a�� �%�3��� ��� 326� ���� ;� 7��6���� 4� � 8�2��� 0� � 6� ������a�� �6� �� �=� � ?� 60��� 60<�� �%�3������������ � ��; ��27���<�@0<2<������a���%�3������� 0��0807��6�?� 0�60����� ��; � ��6�0�� 6 ���6=;� ��8�9�7:8 206��% ��6=;��. 0�����b�c�a��; ��27���<�@0<2<��?� ����;� 7��6�����8�32�3� 8����4���3=�+� � ����b�5�a������) �9���5c�b�a���% �� � 2�6 �4� ��?� =�7�� ��6��6 ��80��0�� ��8� � �60���6��������bb�������2 ����?�����c����% �=��36�0�����b���6�������;� 7��6�32�3�0��6 ��8 206�� % �� 0�6� �760��� �88�76� �8� � ?� 60��� 60<�� ���� 6=;�� 4� � 8�2��� 6�� 3�� 0��0807��6� �%�3��� 5��� % �� � 2�6��8� ���� 62�=��� ����406 �6 ��80��0�� ��8�� �60���6��������bb��6 �6� ����4�0� 6��<�2�60��� 6�����b�;� 7��6��8�6�6���4�0� 6��8�8 206�4 07 �0 �1206�� 0<0�� �6��6 ��6=;��. 0�������+� � ���! ��<� ����5�� 6�6��� 6 �6�) �9�� 6=;�� 7��6�0����b�cb�;� 7��6� �8� ���� ����. 0��� 6=;�� 7��6�0��������� ;� 7��6��% �� 0�6� �760���4� �� 8�2��� 6��3�� 0��0807��6��% ��<�@0<2<�;� 7��6�����8� �7 0 �4� � 8�2����6�<0�� � ?� 60���60<��4 07 �4� �8����4���3=��� �=�������6�� � ?� 60���60<���'��6 ���6 � � ����<�@0<2<�;� 7��6���������a���8� �7 0 �4� �8�2���8 �<�) �9��6=;������<0�0<2<�����5a�� �5� � = 07���" � �76� 0 607 ��8���7:8 206� 8 �<� . 0��� ?� 0�6=� 4 07 � 4� � �� ���� 406 � 6 �� 80��0�� � �8� �� �0�� ����c�� 4 �� �39� ?��� 6��� �088� ��6� 6=;�� 9�7:8 206� ���� 8�2��� �?� ���� �7 0 � 6�� 3�� ���ca�� % �� 0�6� �760��� 0�� � ;�76� �8� ;� 7��6��8� �7 0 �4� � 0��0807��6� �%�3���5��� !6�4� ��3 � ?��� 6 �6� 6 �� 0���;� 7��6����4� � 8�2��� <�@0<2<� ��b���a�� �6� ��6�� � ?� 60��� 60<�� 4 0��� 06� 4� � <0�0<2<� �6� <0�� � ?� 60��� 60<�� �5��5�a���% ��;� 7��6�����8� 0����� ��?� 0����<����6 ���6=;���8�9�7:8 206��) �9��; 2�27���6 �� 0� � 6� ;� 7��6���� �����ba�� �8� 0��� 4 07 � 4� � 8����4��� 3=� . 0��� �5c���a�� ���� +� � �� �5����a���% ��; � ��6� � 2�6 �4� ��?� =�7�� ��6��6 ��80��0�� ��8�����=<�2 ������������� �60�� �6��������bb����� �0������c���3 � ?���6 �6� 0���7��6��6 ��8�6 ��9�7:8 206��8�6���6=;� �4� ��0��6 �� �����8 �<��c���a�6���c���a��% ��0�6� �760���3�64���� � ?� 60���60<������6=;��4� ��8�2���6�� 3�� 0��0807��6�� ���� "��7�2 0��"��7�2 0��"��7�2 0��"��7�2 0������ ���� �� ������6 �� � 2�6 �06�<0� 6�3��7��7�2����6 �6�<0�������� �=� � ?� 60���60<� �4� ��3�66� �8� �6 �� 9�7:8 206�326���6�� � ?� 60���60<��4� ���6��� 0 �3���� �6 ��12��06=��8�8 206 ���6� 0� �6� �406 �60<��� � $�8� ��7� $�8� ��7� $�8� ��7� $�8� ��7� ���� ���� ����=<�2 �� ���b�� �� 62�=� ��� 6 �� ; = 07��7 �<07��� 7 � �76� 0 607 � �8� 6 ��� 6=;�� �8� 9�7:8 206� �6� �088� ��6� 6��� ��8� 0;��0��������2 0��� 6� �����6��088� ��6�7���060����/� 7������6 � 0 ��+�;6�� �8��� 6072�62 ����������� ��� 072�62 ���*�0?� 06=��/=<�� 0�� ��c;�� ����=<�2 ������� 62�=� ��� 6 �� ; = 07��7 �<07��� 7 � �76� 0 607 � �8� 9�7:8 206� �6� �088� ��6� � ?� 60��� 60<��� /� 7������� 6 � 0 �� +�;6�� �8� �� 6072�62 ��� �������� � �� 072�62 ��� *�0?� 06=�� /=<�� 0�� ��b�;�� �f�������)������� 62�0� ����8�� ���30����=��;�66� ���8�8 206 �6�����12��06=��8�8 2060 �3� ���0���088� ��6� �760���� �8� 9�7:8 206� ;���6 �� /� 7�� ������ 6 � 0 �� +�;6�� �8� �� 6072�62 ��� ��*�� /=<�� 0�� �� ;;�������� �� �� ���5�� ��� � 3��:� �8� �� 072�62 ��� 6�60 607 � �8� �������� �� �������� � �2 ��2� �8� 6�60 607 �� 6�60 607 �+0?0 0����/0�0 6 =��8������0���.�?� �<��6��8�6 �����;�� �$�;23�07��8���������� �� ;;�������� � �60������ ���"�� �� 0���;;������.��#������bb��"�<;� 060��������26 060?��?��2���8�9�7:8 206��!������� �� 07�� 70���b�����5��5c�� ��303�����(�����5��-0?0;� =�0��� 6�7� ;2 � �6� �; =��2 �#�<��/= � �������� 07�� 70����������������� ��12���/��������5��"����760��������?��2�60����8��088� ��6�9�7:8 206�7���� ��8��������� ����*�$� �� � �������������b�� �� �0���/�����������12��������� 62�0� ����; = 07��� 7 � �76� 0 60� ��8� 9�7:8 206���������� ��� 6�� b���������� �� �0���/�����c�� 62�0� ����6 ��; = 07���7 � �76� 0 607 ������26 060?��?��2���8�9�7:8 206��� 6�7� ;�2 � �6� �; =��2 �#�<���/�� 7��������6 � 0 ��+�;� 6<��6��8��� 6072�62 �����*��/=<�� 0�� �bb;�� ! ��<��/��'�����5�� 62�0� ���� ������ <0��60������� ����0���/� ; ����0� ��8�9�7:8 206��� 6�7� ;�2 � �6� �; =���2 �� 0�� ���60��� 6�� � �46 �� /�� 7�� 6 � 0 �� +�;6�� �8� " �;� ��6��=�� ��*�� /=<�� 0�� ��;;����5��� )�<��2��0������ ��/�� ��cc�� j� � ��� �" � � �0�� ��������� )�<�2��,� � �� ��� (���90<;2 ���2 0��� & 6�����+ �:���;;���������� ��� ! 0���6����� /�4 =�������b5��/0 7�������2 �% �;07������� 23�6 �;07���(�� 0���( 206 ���2���60����bc��*�0?���8�(���� ����&@6�� � ?���.�0�� ?0�����;;����5���� �2 ����?��� ���g����c���% �;07���" �; ��+07�6=����� ����#���<�� ��. ��������"���#6����#������ ����/� ��4��;;�5���55c�� � � � � � microsoft word 4. baj-220_revised.docx bangladesh agron. j. 2016, 19(1): 29-36 effect of sowing time based temperature variations on growth, yield and seed quality of garden pea m. z. ali1, m. a. aziz1, m. a. i. sarker1, s. mazumder2, s. k. paul1*, t. a. mujahidi3 m. s. a. khan1 and m. s. bhuiyan1 1agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. 2sher-e-bangla nagar adarsha mohila college, dhaka-1207 3scientific officer, plant breeding division, bangladesh agril. res. institute, joydebpur, gazipur-1701, bangladesh *corresponding author: santosh87dhaka@gmail.com key words: temperature, gardenpea, phenology, growth, yield, seed quality abstract a field experiment was conducted at the research field of agronomy division, bari, joydebpur, gazipur and ars, burirhat, rangpur to evaluate crop growth, yield and seed quality of garden pea in prevailing temperature at different sowing dates (10 november, 20 november, 30 november, 10 december, 20 december and 30 december). sowing date based temperature variations significantly affected the crop growth, tdm production, yield and seed quality of bari motorshuti-3. plants with november 20-30 sowing performed the best in respect of yield and yield contributing characters. however, with the delayed in sowing dates, the temperatures at the later growth phases were increased, while the grain growth duration, grain yield and grain quality decreased substantially. results revealed that november 20-30 would be the optimum time of sowing for maximum yield with quality seed production of garden pea in bangladesh. introduction the garden pea is grown mainly for young pod to get tender green seeds as vegetable. the mature seeds can be used for preparing dal or chatpati. the crop has gained popularity for its short growth duration and high nutritive value. green pods are rich in vitamins, protein and minerals. besides, a huge amount of garden pea is consumed as soup. garden pea can play an important role to over come our national protein deficit. its demand especially to the urban people is increasing day by day. garden pea is a cool loving crop. it grows well in winter and partly moist climatic condition. an increase in temperature above 20 °c decreases the yield and quality of immature seeds. temperature above 30 °c is harmful for garden pea (sousa-majer et al., 2004). temperature is an important environmental factor that affects the growth of plants in several ways, from root growth, nutrient uptake, and water absorption from the soil, to photosynthesis, respiration, and translocation of photosynthate. sowing at proper time allows sufficient growth and development of a crop to obtain a satisfactory yield because high temperature is one of the major environmental stresses that affect plant growth and development (boyer, 1982). high temperature affects a host of physiological processes, the most relevant of which are respiration, photosynthesis, photosynthate translocation and membrane composition and stability as a result the crop yield decrease (sing, 2006). it was reported that different environmental conditions, especially temperature due to different sowing time provide variable in crop growth, development and yield stability (pandey et al., 1981). so, it is necessary to study the crop growth behaviors in changing climatic condition for future requirement. therefore, the 30 ali et al. present experiment was conducted to evaluate the crop growth pattern, yield and seed quality under different temperature resulted from different sowing time. materials and methods the trial was conducted at the research field of agronomy division, bari, joydebpur, gazipur and ars, burirhat, rangpur during rabi season of 2011-2012 to find out the crop growth pattern, yield and seed quality under different temperature resulted from different sowing time. six sowing dates (10 november, 20 november, 30 november, 10 december, 20 december and 30 december) were evaluated in rcb design with 3 replications. the unit plot size was 3 m x 4 m. garden pea var. bari motorshuti-3 was used in the experiment. fertilizers @ n60p28k40s12 kg/ha were applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and zinc sulphate, respectively. all fertilizers were applied as basal. intercultural operations such as weeding, thinning and irrigations were done as and when required. for dry matter estimation and crop growth analysis, 5 plants were sampled at 5 days interval up to maturity. the collected samples were dried component-wise in an oven at 70 °c for 72 hours. the yield component data was taken from 10 randomly selected plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise. the collected data were analyzed statistically and the means were adjusted following lsd test. seed protein content was analyzed by neo infrared analyzer (nir) (da 7200 diode array analyzer). following ista (1999) rules seed quality such as moisture (%) content, seed germination (%) and vigor index (abdul-baki and anderson, 1973) were recorded by the following formulae: % moisture content = 100 x m m m m 12 32   where, m1 = weight in grams of the container and its cover, m2 = weight in grams of the container, its cover and garden pea seed before drying, and m3 = weight in grams of the container, cover and garden pea seed after drying seed germination (%) = 100 x testedseed total germinated seedof no. vigor index (vi) = average seedling dry weight (g) x seed germination (%) leaf area index (lai) = )(m2/m area ground arealeaf 2 results and discussion phenology and crop growth duration was influenced by prevailing temperature variations. november 30 sowing took maximum dura++tion for crop growth (84 days) followed by 20 november (83 days) and 10 november (81 days) and it was 77, 74 and 70 days for 10 december, 20 december and 30 december sowing, respectively. the reasons for variation in growth duration might be due to variation in day/night temperature and increased in temperature at the later sowing curtailed the crop growth duration (table 1a and 1b). 31 effect of sowing time based temperature variations on growth, yield and seed quality of garden pea table 1a. crop phenology and growth duration of gardenpea (bari motorshuti-3) as affected by sowing dates sowing dates emergence (days ) avg. min. tem. 0c at emergenc e stage avg. max. tem. 0c at emergenc e stage duration of vegetativ e stage (days) avg. min. tem. 0c at the vegetativ e stage avg. max. tem. 0c at the vegetativ e stage days to1st flower initiation 10 november 6 19.18 30.92 26 17.40 28.60 27 20 november 6 17.47 29.27 27 15.36 27.02 28 30 november 6 13.58 28.47 26 13.64 25.74 27 10 december 6 15.82 25.75 25 12.81 27.16 26 20 december 6 11.4 25.05 24 12.86 27.53 25 30 december 6 12.3 24.35 22 9.85 22.73 23 table 1b. crop phenology and growth duration of gardenpea (bari motorshuti-3) as affected by sowing dates sowing dates grain growth duration (days) avg. min. tem. 0c in grain growth stage avg. max. tem. 0c in grain growth stage crop growth duration (days) avg. min. tem. 0c in total crop growth duration avg. max. tem. 0c in total crop growth duration 10 november 48 11.96 24.24 81 14.26 25.37 20 november 49 11.05 24.50 83 12.41 25.66 30 november 51 11.13 24.03 84 12.30 25.31 10 december 45 12.16 26.98 77 12.59 26.22 20 december 43 13.17 27.34 74 12.91 26.48 30 december 41 14.16 28.61 70 12.97 26.94 grain growth duration of 30 november, 20 november and 10 november sowings were longer due to low temperatures (min. 11.05 11.13 °c and max 24.03 24.24 °c) prevailed at those time that might prolonged the grain growth period (48-51 days). on the contrary, 30 december and 20 december and 10 december sowings received high temperatures (min. 12.1614.16 °c and max 26.9828.61 °++c) that shorten the grain growth period of bari motorshuti-3 (41-45 days). similar results were observed by gardner (1985), savin and nicolas (1996) who reported that high temperature reduced the length of reproductive period. leaf area index (lai) varied at different sowing dates. lai increased up to 40 dae and thereafter decreased in all the sowing dates (fig.1). irrespective of sowing dates, maximum lai was recorded in 30 november sowing followed by 20 november and 10 november sowings. higher lai indicates better leaf area expansion, which might helped in solar 32 ali et al. radiation interception and efficient utilization of light for more dry matter production. the lowest lai was recorded in 30 december followed by 20 december sowing. fig. 1. effect of sowing dates on leaf area index of bari motorshuti-3 total dry matter (tdm) production increased gradually with the advancement of growth at different sowing dates (fig. 2). tdm of 30 november sowing was higher which was more or less similar with 20 november and 10 november sowing. low temperatures might favor the growth of early sowing (30 november, 20 november and 10 november) that caused higher tdm production. the lowest tdm was found in 30 december sowing followed by 20 december and 10 december sowings. fig. 2. total dry matter of garden pea var. bari motorshuti-3 as influenced by different sowing dates crop growth rate increased up to 40-55 days after emergence of crop then it decreased in all the sowing dates (fig. 3). higher cgr up to 40-55 dae might be due to higher lai. at the later stages of crop growth, declined in cgr caused by mutual shading and leaf senescence which might reduced the photosynthetic efficiency and ultimately reduced the dry matter accumulation rate. similar findings were also observed with different crop species by friend et al. (1962), wall and cartwright (1974), stern and kirby. (1979). 33 effect of sowing time based temperature variations on growth, yield and seed quality of garden pea fig. 3. effect of sowing dates on the crop growth rate of garden pea var. bari motorshuti-3 significant differences were found in plant height, pods/plant, seeds/pod, 1000-seed weight and seed yield/ha due to variation of sowing dates at joydebpur and rangpur (table 2a and 2b). significantly the tallest plant (56.63 cm at joydebpur and 46.3 cm at rangpur), maximum number of pods/plant (17.47 at joydebpur and 15.7, rangpur), seeds/pod (4.47 at joydebpur and 6.0 at rangpur) and highest 1000-seed weights (255.19g at joydebpur) were recorded in 30 november sowing. december 30 sowing gave the shortest plant (36.53 cm at joydebpur and 37.0 cm at rangpur), minimum number of pods/plant (12.19 at joydebpur and 9.3 at rangpur), and seeds/pod (2.91 at joydebpur and 4.0 at rangpur) and lowest 1000-seed weight (203.07g at joydebpur). table 2a. effect of sowing dates on yield components and seed yield of bari motorshuti-3 at bari, joydebpur, gazipur sowing dates plant height (cm) pods/plant (no.) seeds/pod (no.) 1000-seeds/ weight (g) seed yield (t/ha) 10 november 51.97 13.67 4.21 222.14 2.90 20 november 50.63 15.89 4.21 245.16 3.56 30 november 56.63 17.47 4.47 255.19 3.66 10 december 42.63 13.01 3.01 220.22 2.36 20 december 37.33 12.44 3.71 215.66 2.27 30 december 36.53 12.19 2.91 203.07 1.19 lsd(0.05) 5.053 0.91 0.57 10.77 0.38 34 ali et al. cv (%) 6.04 3.55 8.32 2.61 7.78 table 2b. effect of sowing dates on yield components and seed yield of bari motorshuti-3 at ars, burirhat, rangpur sowing dates plant height (cm) pods/plant (no.) seeds/pod (no.) seed yield (t/ha) 10 november 42.0 13.3 4.7 1.98 20 november 45.0 15.7 6.0 2.43 30 november 46.3 15.7 5.3 2.36 10 december 45.7 14.0 4.7 2.03 20 december 39.7 11.0 4.3 1.68 30 december 37.0 9.3 4.0 1.58 lsd(0.05) 5.16 1.10 0.94 0.25 cv (%) 6.66 5.05 8.85 6.91 november 30 sowing received lower day/night temperature that causes longer crop growth duration specially the grain growth period and ultimately more tdm production and translocation of tdm to pods/plant, seeds/pod and 1000-seed weight. on the other hand, 30 december sowing received higher day/night temperature that hastens forced maturity and reduced tdm production and translocation to the yield components. similar results were recorded by peterson and loomis (1949) in kentucky bluegrass, gardner and loomis (1953) in orchard grass, lindsey and peterson (1964) in poa pratensis l. fig.4. maximum and minimum temperature during garden pea (bari motorshuti-3) growing period (2011-2012) at bari, joydebpur, gazipur. 35 effect of sowing time based temperature variations on growth, yield and seed quality of garden pea fig. 4. maximum and minimum temperature during gardenpea (bari motorshuti-3) growing period (2011-2012) at ars, burirhat, rangpur. seed yield is the function of pods/plant, seeds/pod and 1000-seed weight. date of sowing significantly influenced the seed yield/ha of garden pea. november 30 sowing produced the highest seed yield (3.66 t/ha at joydebpur and 2.43 t/ha at rangpur) which was statistically similar with 20 november sowing at both the location. the lowest seed yield (1.19 t/ha at joydebpur and 1.58 t/ha at rangpur) was obtained in 30 december sowing and it was identical with 20 december sowing at the both location joydebpur and rangpur. the highest seed yield at 30 november might be due to maximum number of pods/plant and seeds/pod and highest 1000-seeds weight. this study indicated that raise in temperature reduced the grain growth duration resulted in yield reduction, which is in agreement with the findings of mohanty et al. (2001), bosswell (1926), kruger (1973) and silim et al. (1985). seed quality character also affected significantly due to different dates of sowing. at joydebpur, significantly the lowest moisture content (12.10%), higher germination percentage (97%), maximum vigor index (2.52) and highest protein content (26.51%) was recorded in 30 november sowing. the highest moisture content (12.64%), lower germination percentage (91.33%), minimum vigor index (1.65) and lowest protein content (25.70%) was recorded in 10 december sowing (table 3). table 3. effect of sowing dates on seed quality characters of bari motorshuti-3 sowing dates moisture content (%) germination (%) average seedling dry weight (g) vigor index protein content (%) 10 november 12.43 93.33 0.019 1.79 25.85 20 november 12.38 95.00 0.023 2.19 26.24 30 november 12.10 97.00 0.026 2.52 26.51 10 december 12.49 93.67 0.018 1.69 25.08 20 december 12.59 92.33 0.018 1.66 24.21 30 december 12.64 91.33 0.018 1.64 22.70 lsd(0.05) 0.02 3.28 0.002 0.25 0.41 cv (%) 0.12 1.92 6.60 7.28 0.90 conclusion from this study it might be concluded that november 20-30 would be optimum time of sowing for maximum seed yield and quality seed of garden pea. references abdul-baki, a. a. and j. d. anderson. 1973. vigor determination in soybean seed by multiple criteria. j. crop. sci. 13: 630-633. boswell, v. r. 1926. the influence of temperature upon the growth and yield of garden peas. proceedings of the american soc. hort. sci. 23: 162-168. boyer, j. s. 1982. plant productivity and environmental, science 218: 443-448. 36 ali et al. friend, d. j. c., v. a. helson and j. e. fisher. 1962. leaf growth in marquis wheat, as regulated by temperature, light intensity and day length. can. j. bot. 40: 1299-1310. gardner, f. p. and w. e. loomis. 1953. floral induction and development in orchard grass. plant physiol. 28: 201-217. gardner, f. p., r. b. pearce and r. l. mithchel. 1985. physiology of field crops. the iowa state univ. press, iowa. 50010: 156-186. ista. 1999. international rules for seed testing. seed science and technology. international seed testing association, zurich, switzerland. 27:155-199. kruger, s. n. 1973. effect of time of planting on the seasonal yield of pisum sativum l. qld. j. agric. anim. sci. 30: 25-38. lindsey, k. e. and m. l. peterson. 1964. floral induction and development in poa pratensis l. crop. sci. 4: 540-544. mohanty, s. k., b. baisakih., u. k. dikshit and b. bhol. 2001. kalamung, a promising local mungbean cultivar. environ. ecol. 16(1): 222-223. pandey, b. p., s. k. sirvastava and r. s. lal. 1981. genotype and environment interaction in lentil. lens. 8: 14-17. peterson, m. l. and w. e. loomis. 1949. effect of photoperiod and temperature on growth flowering of kentucky bluegrass. plant physiol. 24: 31-43. savin, r. and m. e. nicolas. 1996. effect of short periods of drought and high temperature on grain growth and starch accumulation of two malting barley cultivars. aust. j. plant physiol. 23: 201-210. silim, s. n., p. d. hebblethwaite and m. c. heath. 1985. comparison of the effects of autum and spring sowing date on growth and yield of combining peas (pisum sativum l). j. agric. sci. 104: 35-46. sing, b. d. 2006. breeding for resistance to temperature stress. plant breeding principle and methods. new delhi, india. 7: 510-511. sousa-majer. m. j., turner. n. c., d. c. hardle., l. r. morton., l. morton and j. v. thomas. 2004. response to water deficit and high temperature of transgenic peas (pisum sativum l.). j. exp. bot. 55(396): 497-505. stern, w. r. and e. j. m. kirby. 1979. primordium initiation at the shoot apex in four contrasting varieties of spring wheat in response to sowing date. j. agric. sci. 93: 203-215. wall, p. c. and p. m. cartwright. 1974. effects of photoperiod, temperature and vernalization on the phenology and spikelet numbers of spring wheats. ann. appl. biol. 76: 299-309. microsoft word 3. baj-218_revised.docx bangladesh agron. j. 2016, 19(1): 19-28 photosynthesis, dry matter partitioning and yield variation in sesame genotypes m. akter1, q. a. khaliq1, m. r. islam1 and j. u. ahmed2 1department of agronomy, 2department of crop botany bangabandhu sheikh mujibur rahman agriculturaluniversity,gazipur-1706 corrosponding author: aktermunny026@gmai.com key words: photosynthetic rate, light interception, dry matter partitioning, seed and oil yield, sesame abstract an experiment was conducted at the research field of bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 from march to june 2014 to evaluate growth and yield performance of sesame genotypes. five sesame genotypes i.e. db-6992, bd-6995, bd-7001, bd-7011 and hathazari-4 were used in the study. the genotypes significantly differed in photosynthetic rate, dry matter partitioning and seed yield. the earliest genotype was hathazari-4 and the latest was bd-7011. the highest stem dry weight, leaf dry weight, capsule dry weight, leaf area index, light interception, photosynthetic rate were recorded in genotype hathazari-4. the number of capsules plant-1 and the number of seeds capsule-1 were also highest in the genotype hathazari-4, while the lowest was being noticed in the genotype bd7001. weight of 1000-seed was the maximum in genotype bd-6992 and the minimum in the genotype bd7011. the highest seed yield (3.52 tha-1) was recorded in the genotype hathazari-4 and the lowest in the genotypes bd-6992 followed by bd-7001. the highest oil content (41.39%) was recorded in the genotype bd-6992 and the lowest (39.72%) in the genotype hathazari-4 but the highest oil yield (1.53 t ha-1) was recorded in the genotype hathazari-4. it may be concluded that the sesame genotype hathazari-4 may be cultivated for higher seed yield and oil production. introduction sesame (sesamum indicum l.), known as “til” in bangladesh, belongs to the family pedaliaceae. average sesame yield in bangladesh is about ha-1. currently, about 33275 hectares of land are under sesame cultivation and annual production is about 29,965 m tons (bbs, 2012). in bangladesh it is grown in almost all districts but grows well in greater khulna, faridpur, pabna, barisal, rajshahi, jessore, comilla, dhaka, rangpur, sylhet, and mymensingh districts. sesame is cultivated in both kharif i and kharif ii seasons, but twothird of sesame is produced in kharif i season. sesame needs a constant high temperature ranging from 26 to 300c for optimum growth. sesame requires a minimum of 300–400 mm rainfall (carlsson et al., 2008). sesame seeds contain 38-54% oil, 18-20% protein, 567 kcal energy, 26.04 g carbohydrates, 5 g water, 131 mg calcium, 7.78 mg iron etc. in 100 g of seed (banglapedia, 2012). the oil is utilized for the manufacture of soap, insecticide and paint (vaughan, 2000). the seed is used in making various food items like bread, cakes, pastry, khaja, biscuits, etc. sesame produces no seed or a very low seed yield if it is grown under unfavorable environmental conditions (pham et al., 2010). another major cause of poor yield of sesame is low yielding cultivars. the yield ability of sesame crop is determined by many yield components, all of which are substantially influenced by environmental conditions and agronomic practices 20 akter et al. (caliscan, 2004). it is important to understand yield potential and the improvement in partitioning of photosynthetic products. photosynthesis is considered as the most important physiological process that governs the growth and yield of crops. photosynthesis process of sesame varied over a wide range of genetical and environmental conditions (ojima et al., 1969). information relating to photosynthetic rate, dry matter partitioning and yield variation in sesame is very limited. therefore, the present study was undertaken to identify the best sesame genotypes based on photosynthetic rate, dry matter partitioning and yield. materials and methods the experiment was conducted at the field research site of the bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 from march, 2014 to june, 2014. it is located in madhupur tract under agro ecological zone (aez) 28. the soil of the experimental site is silty clay in topsoil and silty clay loam in subsoil. the site is situated in the sub-tropical region characterized by heavy rainfall during monsoon at the months from march to june and scanty rainfall in the rest of the months of the year. the five selected sesame genotypes were bd-6992, bd-6995, bd-7001, bd-7011 and hathazari-4. the land preparation was done well by repeated ploughing and cross-ploughing with a tractor drawn disc plough and then harrowed. the experiment was laid out in a randomized complete block design (rcbd) with four replications. the unit plot size was 1.2m × 1.5m. all the treatment plots were fertilized with 43.4, 23, 40.5, 18, 2 and 0.8 kg of n p k s zn and b ha-1, respectively as urea, triple super phosphate, muriate of potash, gypsum and borax (barc, 2012). total amount of triple super phosphate, muriate of potash and gypsum fertilizers were applied plot wise during final land preparation before sowing. 2/3 (43.4 kg) nitrogen as basal and all the fertilizers were applied by broadcasting and mixed thoroughly with soil. onethird (21.6 kg) n was top dressed at 20 days after emergence (dae). sesame seeds at the rate of 3.5 kg ha-1 were sown in line by hand on 3 march, 2014. sesame took 3-4 days to emergence. pre-sowing irrigation was given to ensure the maximum germination percentage. subsequent irrigation was also provided to avoid moisture stress. three times weeding and mulching, two times insecticides spraying were performed to keep the field free from pests. data on agronomic traits regarding on phenological and morphological characters of sesame including days to first flowering, days to maturity, plant height, number of leaves per plant, leaf area index, dry weight of leaves per plant, dry weight of stem per plant were recorded. data on yield and yield contributing characters were measured from randomly selected plants. leaf area index (lai) and light interception (li) were measured by using standard formulae. the formulae used for different parametrs are given below. leaf area index (lai) = plant by occupied area ground arealeaf light transmission ratio (ltr) = 100 io i  where, io = photosynthetically active radiation on the top of the canopy, i = photosynthetically active radiation on the base of the canopy. light interception (li %) = 100 (%) ltr (%) dry weight of leaves per plant = plantsof number (g) weight dryleaf 21 photosynthesis, dry matter partitioning and yield variation in sesame genotypes dry weight of stem per plant = plantsof number (g) weight dryleaf oil content (percent) = 100 samplesof weight (g) extracted oilof weight  oil yield was determined as follows: oil yield (t ha-1) = (%)content oil yieldgrain the collected data were analyzed statistically and the mean differences were adjusted by least significance difference (lsd) test at a significance level of 0.05 (gomez and gomez, 1986). results and discussion phenology there was variation among the genotypes in relation to flowering. table 1 showed that days required for first flowering of sesame genotypes varied from 26 to 32 days and 50% flowering from 43 to 51 days. the genotype hathazari-4 flowered within 34 days while bd7001 took 41 days for flowering. other genotypes such as bd-6992, bd-6995 and bd-7011 also took longer time for flowering. four sesame genotypes required intermediate time for flowering ranging from 35 to 41 days. among the genotypes the hathazari-4 flowered and matured earlier than other genotypes. table 1. phenological events of five sesame genotypes days to genotypes 1st flowering 50% flowering maturity bd-6992 32 41 85 bd-6995 30 40 83 bd-7001 31 41 83 bd-7011 30 41 85 hathazari-4 26 34 76 lsd (0.05) 0.64 0.64 1.14 cv (%) 1.39 1.06 0.90 morpho-physiological characters plant height the sesame genotypes differed significantly in height at all stages of their growth but not at initial stage. irrespective of genotypes, the height of sesame plants increased rapidly at the early stages of growth and rate of progression in height was slow at the later stages (table 2). the genotypes attained their peak height at maturity. plant height ranged between 124.7 cm and 137.3 cm. hathazari-4 produced the tallest plants (137.3cm) and bd-6992 the shortest (124.7 cm). all genotypes attained their peak height at 85 days after emergence (dae) . plant height is an important morphological character of crop that showed positive correlation with seed yield of sesame although it may be reversed in other circumstances (rubio et al., 2004). 22 akter et al. number of leaves per plant table 2 shows the number of leaves in sesame genotypes throughout the crop duration. in sesame plant, the highest number of leaves per plant (35.3) was found in the genotype hathazari-4. number of leaves per plant increased during early growth stages of sesame and decreased later due to leaf senescence. leaves play a major role in synthesis and translocation of photo-assimilates to the seeds and affect grain yield. a strong relationship exists between lai and number of leaves per plant i.e. more number of leaves per plant ensures increased canopy cover and increased photosynthetic activity (saipan et al. 2010). table 2. variation in plant height and leaf number over time in five sesame genotypes plant height (cm) leaf number genotypes 20dae 40dae 60dae 85dae 20 dae 40 dae 60 dae bd-6992 32.47 101.20 123.00 124.70 8.65 26.70 18.35 bd-6995 32.47 103.50 133.01 134.40 8.35 23.00 18.35 bd-7001 33.88 102.10 129.20 130.60 8.80 27.90 21.35 bd-7011 33.92 112.20 129.70 131.20 9.00 26.00 20.05 hathazari-4 33.17 114.60 136.30 137.30 10.55 35.30 25.95 lsd (0.05) ns 6 8 8 1.42 5.32 5.04 cv (%) 7.69 4.66 4.47 4.44 10.13 12.43 14.90 ns = non-significant leaf area indices table 3 shows the lai of sesame genotypes throughout the crop duration. lai increased progressively from early growth stages of sesame and attained peak at 40 dae and then decreased gradually. the genotypes differed in lai at all the sampling dates. among the genotypes hathazari-4 had the highest lai in all sampling dates. leaf area index is most important for interception of light and photosynthesis. the more lai caused more photosynthesis and produced more dry matter. the initial increase of lai in sesame is associated with the higher number of leaves per plant and higher photosynthetic leaf surface area. the decline in lai after attaining the peak might be due to senescence of leaves from the base of the stem approaching upward. leaf area index and activity per unit leaf area are components of field photosynthetic performance (de costa and shanmugathasan, 2002). table 3. variation in leaf area and leaf area index over time in five sesame genotypes leaf area per plant (cm2) leaf area index genotypes 20 dae 40 dae 60 dae 20dae 40dae 60 dae bd-6992 227.9 819.1 705.4 0.57 2.05 1.76 bd-6995 239.7 845.1 715.3 0.59 2.12 1.79 bd-7001 200.3 848.8 730.9 0.50 1.87 1.80 bd-7011 205.3 746.9 719.4 0.51 2.12 1.83 hathazari-4 316.1 1246 889.1 0.79 3.11 2.22 lsd (0.05) 67.50 210.1 56.47 0.17 0.53 ns cv (%) 18.42 15.23 15.36 18.36 15.26 0.53 ns = non-significant light interception interception of light at capsule initiation stage of sesame genotype is presented in table 4. in hathazari-4 the maximum amount of light was intercepted at capsule initiation stage. from the table 4 it is revealed that light penetration through the canopy is genotype dependent. the genotypes bd-7001 transmitted more portion of radiation to ground level in comparison 23 photosynthesis, dry matter partitioning and yield variation in sesame genotypes to hathazari-4 indicating that canopy of bd-7001 is less efficient in light interception. the genotype hathazari-4 intercepted highest amount of light at capsule initiation stage which was 95.00%. the more the lai, greater was the light interception. the lowest light interception was 87.21% in the genotype bd-7001. this was attributed to lower lai. the amount of light intercepted by a canopy is a function of lai. maximizing light interception during seed formation is required for maximum yield. light capture is highly affected by canopy size, and the amount of par intercepted by crops along the season is commonly related to crop growth and grain yield (singer, 2001). table 4. variation in light interception at capsule initiation stage in sesame genotypes genotypes light interception at capsule initiation stage (%) bd-6992 93.02 bd-6995 94.63 bd-7001 87.21 bd-7011 92.49 hathazari-4 95.00 lsd (0.05) ns cv (%) 3.94 photosynthesis growth, dry matter production and yield depend almost entirely on photosynthesis of crop plants. photosynthesis depends on the leaf area development and the extent of light intercepted by the canopy. variation in leaf photosynthesis was low at the capsule development stage in five sesame genotypes (table 5). higher leaf photosynthetic rate was recorded in the genotype hathazari-4 (28.87µmolm-2s-1) but it was not significant compared to the sesame genotypes. the amount of photosynthate is a function of total leaf area and solar radiation intercepted by the crop canopies. differences in photosynthetic rate among crop varieties are important for understanding the plant capacity to produce economic yield (islam et al., 1994). intercellular co2 concentration there was no significant difference in intercellular co2 concentration (ci) in sesame leaves due to genotypic variation and it ranged from 222.9 to 239.9 ppm at capsule initiation stage (table 5). the lowest intercellular co2 (222.9 ppm) was observed in the genotype hathazari-4 and the highest (239.9 ppm) in the genotype bd-7001. higher intercellular co2 concentration might have been due to slower photosynthetic rates of leaves (hasan, 1993). stomatal conductance stomatal conductance was positively correlated to the photosynthetic rates of sesame. at capsule initiation stage, the highest stomatal conductance (0.80 cms-1) was recorded from the genotype hathazari-4. this apparently was due to faster rate of intercellular co2 utilization compared to the rate of co2 uptake through stomata in this genotype. table 5. variation in photosynthetic rate, stomatal conductance and intercellular co2 concentration at capsule initiation stage in five sesame genotypes genotypes photosynthetic rate (µmolm-2 s-1) stomatal conductance (cms-1) intercellular co2 concentration (ppm) 24 akter et al. bd-6992 27.98 0.59 238.3 db-6995 27.49 0.56 233.1 db-7001 27.40 0.54 239.9 bd-7011 27.09 0.62 234.1 hathazari-4 28.87 0.80 222.9 lsd (0.05) ns ns ns cv (%) 6.28 0.25 5.36 ns = non-significant spad value the spad value is closely correlated with leaf chlorophyll content. chlorophyll is a basic component for photosynthesis. higher the leaf chlorophyll content, faster is the photosynthesis. at early stage of plant leaf chlorophyll concentration was lower. with the advancement of crop growth, chlorophyll content of leaf increased at a parabolic shape reaching peak at around 50dae and then declined. the highest spad value (48.15) was obtained at 40 dae in the genotype bd-6995 and lowest (42.95) in the genotype bd-7011 (table 6). the variation observed in spad value among the genotypes might be due to difference in genetic constituents and environmental effect. reduction in spad value in later stage due to maturity of leaves and leaf senescence has already occurred in reproductive stage. table 6. variation in spad value over time in five selected sesame genotypes spad genotypes 20dae 30dae 40dae 50dae 60dae bd-6992 36.20 42.15 45.28 41.08 35.70 bd-6995 34.45 43.50 48.15 43.08 34.95 bd-7001 37.25 41.88 46.65 43.03 35.45 bd-7011 33.72 41.50 42.95 40.20 34.22 hathazari-4 41.95 45.28 47.6 43.70 39.00 lsd (0.05) 3.45 3.22 4.80 4.48 3.50 cv (%) 6.10 4.87 6.75 6.89 6.28 dry matter partitioning leaf dry weight dry matter partitioning into leaf increased linearly up to a certain period and then gradually decreased regardless of genotypes (figure 1). regardless of genotypes, the accumulation of dry matter in leaf increased over time reaching a peak at around 60 dae in sesame genotypes. at the attainment of peaks, leaf dry weights were 4.73g plant-1 (bd-6992), 4.12 g plant-1 (bd-6995), 4.31gplant-1 (bd-7001), 4.78g plant-1 (7011) and 6.15g plant-1 (hathazari4) in sesame genotypes, respectively. the maximum leaf dry weight was recorded in the genotype hathazari-4 (6.15g plant-1). the genotypes showed significant differences in dry matter accumulation in leaf in all sampling periods. the leaf dry weight decreased after the attainment of the peak in all the genotypes. this decrease in leaf dry weight might be due to translocation of assimilates from leaves to reproductive organs. leaf dry weight increased with increase in leaf size and chlorophyll content, delayed maturity time and increased vegetative growth period as stated by (haruna et al., 2011). 25 photosynthesis, dry matter partitioning and yield variation in sesame genotypes fig. 1. vatiation in leaf dry matter accumulation over time in sesame genotypes. vertical bars indicate lsd (0.05). stem dry matter dry matter accumulation in stem as a result of stem elongation and stored photosynthates showed a significant variation in sesame genotypes over time as shown in figure 2. the stem dry weight increased slowly up to 20dae and continued to increase till maturity. the highest stem dry weight was obtained at 60 dae which was 9g plant -1, 9.6 g plant-1, 9.1 g plant-1,9.46 g plant-1 and 11g plant-1 in bd-6992, bd-6995, bd-7001, bd-7011 and hathazari-4, respectively. the dry weight of stem declined after the attainment of the peak in all the genotypes. there was slight decrease in stem dry weight at final harvest. this might be due to continuous supply of current assimilates for the development of grains. fig. 2. variation in stem dry matter accumulation over time in sesame genotypes. vertical bars indicate lsd (0.05). capsule dry matter figure 3 shows that the accumulation of dry matter in capsule was less at the beginning and it increased rapidly later on. dry matter accumulation in capsule started earlier in hathazari4. capsule dry weight continued to increase till maturity. the genotypes showed significant differences in capsule dry weight in 40 dae and 85 dae. capsule dry weight ranged from 26 akter et al. 9.7 g plant-1 (hathazari-4) to 6.98 g plant-1 (bd-7011). the highest contribution to total dry weight per plant was made by capsule dry weight per plant. the highest contribution of capsule to the total dry weight could be attributed to the fact that at flowering, most of the assimilation was partitioned to the sink (capsule). this continued until physiological maturity is attained. (haruna et al., 2011). fig. 3. variation in capsule dry matter accumulation over time in sesame genotypes. vertical bars indicate lsd (0.05). yield components of sesame number of capsules per plant there was significant variation in the number of capsules per plant in sesame genotypes (table 7). the highest number of capsules plant-l (63.65) was obtained in the genotypes hathazari-4 and the lowest number of capsules plant-l (38.40) in genotypes bd-7001. number of seeds per capsule the highest number of seeds capsule-l (77) was obtained in genotype hathazari-4. the lowest number of seeds capsule-l (59.83) was obtained in genotype bd-7001which was statistically different. delay in harvesting reduced the number of seeds capsule-l (mondal et al., 2004). thousand seed weight the 1000-grain weight did not vary significantly in the genotypes (table 7). the 1000-grain weight varied from 2.93g to 3.40 g. the highest 1000-grain weight (3.40 g) was recorded in the genotype-bd 6992 and the lowest (2.93 g) in the genotype-bd 7011. the direct effects of 1000-seed weight on seed yield were low and positive. (yadava et al., 1983). seed yield seed yield of five sesame genotypes ranged from 1.83 to 3.52 t ha-1 (table 7). the highest seed yield (3.52 t ha-1) was found in the genotype, hathazari-4 and the lowest (1.82 t ha-1) in the genotypes bd-6992 and bd-7001. oil content in seed 27 photosynthesis, dry matter partitioning and yield variation in sesame genotypes genotypic variation in seed oil content of sesame is shown in table 7. percentage of oil in seeds varied slightly among the genotypes. the seed oil contents were 41.39% in the genotype bd-6992, 39.73% in bd-6995, 40.26% in bd-7001, 41.2% in bd-7011 and 39.72% in the genotype hathazari-4. the highest oil yield was obtained from the genotype hathazari-4 (151.99 tha-1) and the lowest (73.27 tha-1) from bd-7000. table 7. yield component and seed yield, oil content in seeds and oil yield in five selected sesame genotypes genotypes capsules plant-1 seed capsule-1 1000-seed weight (g) seed yield (tha-1) seed oil content (%) seed oil yield (tha-1) bd-6992 47.1 67.15 3.40 1.83 41.39 0.753 bd-6995 44.08 67.63 2.94 2.02 39.73 0.803 bd-7001 38.4 59.83 3.30 1.82 40.26 0.733 bd-7011 45.78 70.07 2.94 2.51 41.20 1.04 hathazari-4 63.65 77.00 3.38 3.52 39.72 1.53 lsd (0.05) 5.00 9.53 ns 0.48 0.62 0.29 cv(%) 6.80 8.89 5.44 13.37 .99 13.23 ns = non-significant conclusion genotypic variability in terms of photosynthetic rate, dry matter partitioning, seed and oil yield was found in five sesame genotypes. based on the present study it could be concluded that sesame genotype hathazari-4 showed the best performance in terms of photosynthetic rate, dry matter partitioning, seed yield and oil yield. references banglapedia. 2012. available from: www.banglapedia.org/ht/s_0249.htm barc (bangladesh agricultural research council). 2012. fertilizer recommendation guide2012. farmgate, new airport road, dhaka 1215. pp. 106. bbs (bangladesh bureau of statistics). 2012. statistical year book of bangladesh. 2012. bangladesh bureau of statistics, statics division, ministry of planning, government of people's republic of bangladesh, dhaka. pp. 91. caliscan, s., m. arstan, h. atiogle and n. isler. 2004. effect of planting method and plant population on growth and yield of sesame (sesamum indicum l) in a mediterranean type of environment. asia j. plant sci. 3(5): 610-613. carlsson, a. s., n. p. chanana, s. gudu, m. c. suh and b. a. were. 2008. sesame. in: c. kole and t. c. hall (eds.). compendium of transgenic crop planttransgenic oilseed crops. wiley-blackwell. pp. 227-246. de costa and k. n. shanmugathasan. 2002. physiology of yield determination of soybean (glycine max l.) under different irrigation regimes in the sub-humid zone of sri lanka. field crops res. 75: 23-35. gomez k. a. and a. a. gomez. 1986. statistical procedures for agricultural research. john wiley and sons, new york, usa. pp. 680. 28 akter et al. haruna, i. m., s. m. maunde and s. yahuza. 2011. growth and calyx yield of roselle (hibiscus sabdariffa l.) as affected by poultry manure and nitrogen fertilizer rates in the southern guinea savanna of nigeria. can. j. pure appl. sci. 5(1): 1345-1348. hasan, m. s. 1993. genotypic variation in yield of blackgram (vigna mungo l. hepper) in relation to morphological and physiological characters. an unpublished m.s. thesis, submitted to the dept. of agronomy, ipsa,gazipur-1703. islam, m. t. 1994. ecophysiological studies on photosynthesis and dry matter production in mungbean. ph.d. dissertation, kyushu university, fukuoka, japan. mondal, m. m. a., r. k. dutta and m. a. islam. 2004. yield performance of some elite mungbean mutant in the northern region of bangladesh. bangladesh j. nuclear arric. 19: 32-35. ojima, m., r. kawashima and k. mikoshiba. 1969. studies on the seed production of soybean. vii. the ability of photosynthesis in f1 and f2 generations. crop sci. soc. japan proc. 38: 693. pham, d. t., t. t. d. nguyen, a. s. carlsson and m. t. bui. 2010. morphological evaluation of sesame (sesamum indicum l.) varieties from different origins. aust. j. crop sci. 4(7): 498-504. rubio, j., j. i. cubero, l. m. martin, m. j. suso and f. flores. 2004. biplot analysis of trait relation of white lupin in spain. euphytica 135: 217-224. sanipan, c., k. d. animesh, s. aditi, s. sonali, p. rita, m. susmita and d. ananya. 2010. traits influencing yield in sesame (sesamum indicum l.) and multilocational trials of yield parameters in some desirable plant types. indian j. sci. technol. 3: 163-166. singer, j. w. 2001. soybean light interception and yield response to row spacing and biomass removal. crop sci. 41: 424-429. vaughan, j. g. 2000. the structure and utilization of oil seed, 1st ed. chapman and hall ltd., london. pp. 201. yadava, t. p., p. kumar and a. k. yadava. 1983. association of yield with some quality attributes in indian mustard. indian j. agric. sci. 53: 685-686. microsoft word final.doc � �������� ��� �������������������������� �� !"#$%&%$'��(!�)# ( *%#+� ,�*%-)!�%($)�#� ��%(.� ,��� !"#$%&%$'��(!�)# ( *%#+� ,�*%-)!�%($)�#� ��%(.� ,��� !"#$%&%$'��(!�)# ( *%#+� ,�*%-)!�%($)�#� ��%(.� ,��� !"#$%&%$'��(!�)# ( *%#+� ,�*%-)!�%($)�#� ��%(.� ,� � $�$ �/%$0� $0)��+0 �$�!"��$% (�&).)$��1)+� $�$ �/%$0� $0)��+0 �$�!"��$% (�&).)$��1)+� $�$ �/%$0� $0)��+0 �$�!"��$% (�&).)$��1)+� $�$ �/%$0� $0)��+0 �$�!"��$% (�&).)$��1)+�������� ������������������������ *�����+ � �2*�����+ � �2*�����+ � �2*�����+ � �2��������*��%��(�3 4�����*��%��(�3 4�����*��%��(�3 4�����*��%��(�3 4����� +��5� �+65��75856� 8856� �� ��,� 9��� �� 6 �!5:5 5����� �������� ��� 564�74 ����� �� 6 �%� 75747������%���+;� �7��������������� �� #� � <�����6���47 � �� 9 �; ��=2� 5>;� ���6�9� ?�;�@� � �?�;�@� � �?�;�@� � �?�;�@� � ��*5a���5�7� 6 �<<5�����b45:����7�;5�����< �857�25�57;��2���857�6� 7� �75�� ���� �2 7 �67�2 7 �67�2 7 �67�2 7 �67���� ���� *5a���6 �<<5��� � �< �:���7��2����4 �84���<< ��6 �7��9�a59535���7 ��6 �<�< ��4675:57;�� (�@� �� ��;�� <�:� 7;� ����:5�75��� �8� � �4 6�� <�� � 8� 9� � 5 � ��� 59<� 7��7� 5 4�� 5�� �������� ����� ��6���95a���6 �<<5��� ; 7�9�6���2�� ��<84��7��8���� �64 57;�� �@����� � 7�� ��46�� <�:� 7;�� $ �� �a<� 59��7�@� � 6� 5��� �47� �7�*�4�:52�3� � ���� +;� �7� �5 7 567 � �4 5��� �������� ���� �������� 7�� 85��� �47� 7 �� �� ���956� <� 8� 9��6�� �8� 95a��� 5�7� 6 �<<5����8�<�7�7��@57 ��588� ��7� � 7��4 �75���:���7�2�� �6 �<�����7��5�6 �� ��7 �� 6 �<<5��� 5�7�� 57;� ���� < �857�25�57;� �8� 7 �� 8� 9� � 5�� +;� �7� ��5���� $ �� 7 5��� @� � 6���467��� 8����@5��� �#�� �� 5��� @57 � 5a� �5 <� ��� �<�56�75�� �� $ � �� @� �� 85:�� 7 ��79��7 ��$��� ����<�7�7�� ����c���$���<�7�7�� ����c��d�24 �2���� �e�c���$���<�7�7�� ����c��d��� ����<����e�c���$���<�7�7������c��d� ��5 ��e�c������$e��<�7�7������c��d� 24 �2���� ��ec��d��� ����<��� ��ec��d� ��5 ����c��4 ��� 5�� 7 �� 7 5������ 4�7 � �:������ 7 �7� 7 �� 5� � 7� �b45:����7� ;5��� � �8� <�7�7�� ������ ���� �e���� 7� ���� @� �� �6� ���� 5�� <�7�7������c��d� ��5 ��e�c��95a���5�7� 6 �<<5��� ; 7�9�8 �9�*�4�:52�3� �����+;� �7�� � <�675:��;��#� 7�2���857�����; 5 ��� ��� �@���7 �7�� 5� � 7�� � � �74 � �$f����������� ������e������������7� �74 � �$f�����e������������g���������2���856�2���857�6� 7� �75�� ��e�� ���� ����� @� �� �6� ���� 5�� 7 �� �9�� 7 ��79��7� 6�925��75��� 5�� 2�7 � ��6�75�� �� � <�675:��;�� +��� ���c� <�7�7�� @57 � e�c� ��5 � 5�7� 6 �<<5��� ; 7�9� 9�;� 2�� �6�99������� �< �857�2���95a���5�7� 6 �<<5��� ; 7�9�5��+;� �7� ��5���� � %�7 ��4675��%�7 ��4675��%�7 ��4675��%�7 ��4675������ ���� %�7� 6 �<<5��� 5 � ��� ��65��7� ���� 7 ��575����� �� ���956� < �6756�� � � 2���� �6���53��� � � �� <�7��75���;�2�8577���7�6 �����;�7��5�6 �� ��6 �<�< ��4675����4��7��57 � 42 7��75���;5������:��7���� 7 ��� ���� 6 �<<5���� %�7� 6 �<<5��� � � �:� ��� ��:��7��� � �:� � 9���64�74 ��� 46 � � � �� ��6�9��7��8��88565��7�4 ���8���:5 ��9��7���8�67� ���������5� 7���47 5��7������ �5��9�5 74 ������� ��2�4 �� ��46� �7 ����:� ���88�67��8�:� 5�4 �25�756������25�756� 7 � ��< �:5�� ��5:� 57;��8�8����� ���� �7� �9� ��5�6�9����88� �5� 4 ��6�����5� 7�6 �<�8�5�4 ��� 5� � � �74 ������7�7���< ��4675:57;� <� � 4�57� � ��� �*� ���� ����/5���;�� ��g�h��f����� ����i4�;;49�� ��g���� +� f� � �7� ���� ������� 4��� 7���7 �7�9�53��� �@��� �5�7� 6 �<�@57 � � 7��4 �75���:���7�2�� ��5f�� ����9� ��7 ��24 � 2���������� ����<���9�;�2��< �857�2���7 ��� ����9�53���+�:� ��� 74�5� � �:���� ��2���� �@��� 7 �7� 5�7� 6 �<<5��� ; 7�9� < �:5��� 5� � � < ��4675:57;� ���� ����� �b45:����7� �75�� 7 ��� ���� 6 �<� �0� �5�������� 5������h��� �f��7����������h���33�b4���7����������h����9��7��������g��������9� �7� ����� ������� +466� 84�� 5�7� 6 �<<5��� ; 7�9� �5:� � 5� � � 6� � �74 ��� 7�7��� < ��4675��� <� � �67� ��� ���� �5:� 585� � < ��4675��� ; 7�9� 7 ��� ���� 6 �<<5��� �'� �6f�� ������ ���� < �:5�� � � ��7� � � �4 6� � 4 �� �88565��6;� ���7 56f� ���� *������ ������� $ �� <���7��� �4 � �$�� �4 �� 56�� �� $ �� <���7��� �9��� �$�� �9���� 56�� �� ,����@� 6 �<<5��� <�77� �� 5 � 7 �� 9�j� � 64�74 ��� < �6756�� 5�� +;� �7� ��5���� ,� 9� � 64�75:�7�� 56�� 6 �<� 9�5��;� 5�� �5�8��� 6���575���� $ �� �5� � 4��� � 7 � �� 6 �<<5���<�77� ��� �� �� ������ ���;� ��:;��6��;����9 �7��6��; �����7 ��7�<� �5��b456f�;�2�6�9� � ��� + � �2��7����� � ;����� � ���87� � 7 �� � :� 7��8�$���9���6 �<��+�����:� 7�� ��� 5�� 7 ���� 7 ��� 7� �� ��5����8� �������� � �9�5� �8����@��4 5���7 �� �25� �� ����4��7����6f��8�9�5 74 ��5�� �5���� ��7�7�� 5 ���9� 7� 59<� 7��7�:���7�2���6 �<� 5���������� ��.��� ���;��<�7�7�� 5 �� �@��� ��� ���� 6 �<� ���� �9�� 8� 9� � � �@� <�7�7�� � �95a��� 6 �<� 594�7����4 �;�@57 � �7 � � 6 �< � 5�� +;� �7� ��5����%��7 5 � ; 7�9��<�7�7��5 �� �@��� ���9�5��6 �<�����7 ���7 � �6 �< ��5f�� ��5 ��24 �2����� �� ����<����6 5��5��76��� ��� �@��� �95a���5�7� 6 �<<5����8�<�7�7���6 5��5��94 7� ��� ��5 ��24 � 2����� �� ���� <��� �76�� 5�� �5��� �@5���9�7 ���� �47�� < �<� � �75�� �8� 6�9<����7� 6 �< � 5���� 7 �� �<75949� ���5��� �75�� 8� � �� 466� 84�� 5�7� �95a��� 6 �<<5��� ; 7�9� 5 � ��7� 8����@���@ 56 � � � � ��7��88�67����< ��4675:57;��8�6�9<����7�6 �< ��0�@�:� �� 5��< �67565���7 �5 ��@�� ; 7�9 �7 �� 8� 9� ��8�+;� �7� �:��2����8�65����588� ��7�< �2��9 �5�� ���75���7��95a���5�7� 6 �<<5���< �6756� � �5f�� <���75��� ���9�7 ;�� ���75:�� �@5���� ���5��� �75��� 759�� �8� 6�9<��5��� 6 �< � 8� � ��775��� 9�a5949�2���857� �76��&� ;� 8�@� 74�5� �� ���95a��� 5�7� 6 �<<5��� �8� <�7�7��@57 � � 7� �4 �75��� :���7�2�� � �:��2���� �<� 7����%��:5�@��7 ��< � ��7�7 5���@� ��� 5�����7�� 74�;�7 ��8�� 525�57;����� �� ���6���956� <� 8� 9��6�� �8� 95a��� 5�7� 6 �<<5��� �8� <�7�7�� @57 � �588� ��7� � 7� �4 �75��� :���7�2�� �6 �<�5��+;� �7�� � *�7� 5�� �����*�7 �� *�7� 5�� �����*�7 �� *�7� 5�� �����*�7 �� *�7� 5�� �����*�7 �� ���� ���� $ �� �a<� 59��7�@� � 6� 5��� �47� �7�94�75��6�75��� 7� 75��� �*1$�� 57���*�4��:52�3� � ���� 8� 95��� ; 7�9� � �� 6 � ���� ��:���<9��7� �,+�!�� 57��� �����<4 �� +�47 � +4 9��� +;� �7� �4 5��� 7 �� 7@�� 6�� �6475:��;�� ��8����������������������$ ��7 5���@� �6���467���5���� ����953���6�9<��7�� 2��6f� ��#��� �� 5��� @57 � 5a� ����� �5 <� ��� �<�56�75�� �� ,5:�� 7 ��79��7 � :53�� $��� ���� <�7�7�� ����c��� $��� <�7�7�� ����c�� d� 24 � 2���� �e�c��� $��� <�7�7�� ����c�� d� �� ���� <��� �e�c��� $��� <�7�7������c��d� ��5 ��e�c������$e��<�7�7������c��d�24 �2������ec��d��� ����<�����ec��d� ��5 ����c��@� ��4 ���5��7 5 �7 5����$ ��4�57�<��7� 53��@� ���9���$ ��85:��;�� ��8�@��7 � ���7�� �:������7 �7�7 �� 5� � 7��9�4�7��8��:� ����9��7 �;� �5�8�����664 �5���4���8����@���2;��4�4 7�� �4�;�����*�;��@ � �� � ��@� 7��9�4�7��8� �5�8�����664 � 5�����4� ;� 8����@���2;�!�6�92� ����� ,�2 4� ;����5�8���� 5�6 �� � � � ��4���;� 8 �9� 7 ��9��7 � �8� ���4� ;� 7�� �4��� ���� 7 �����6 �� � �� �:� ����9�a5949�����95�5949�7�9<� �74 ��@� �����������@� �������#�� � <�675:��;��,5������ $ �� ��� ��8�<�7�7���:� ��!5�9��7��@� �� �@�����������!�6�92� �5��������������(�:�92� � 5��������7�2�7 ���6�75�� �@57 �9�5�7�5�5��� <�65����8����69k��e69��+��� ��8�7 ���7 � �6 �< � :53��� ��5 ��:� �����%�*4�������24 �2�������6���������� ����<�������%�*�7� 475����@� �� �@�� �66� �5��� 7�� �6�99������ ���� �7�� ����� ��; � �87� � �@5��� �8� <�7�7�� 4 5��� 84 �@� l� ���� � 5����� 9�7 ��� 5�� �5�� �� ,� 75�53� � @� �� �<<�5��� � � <� � �5�� 7� 7� 2� 5 � ���� 7 � �� @� �� (�e����?��+��m�����5�� 7 ��8� 9��8�" ����$+���*����.;< 49��m5�6�+4�< �7�������� 56��65��� � <�675:��;��$@��5 5��75�� �������6 ��7������; ��87� � �@5����8�<�7�7���!�+�������e�!�+h����� @���5����7����!�+h�7 ��� < �;5�� ��8���: ���84��565���>��9��1����8�@�7� �8� �6��7 ���5�����7�� 2�5� 7��8�<�7�7��������6 ��7��e��ee������e�!�+�� � <�675:��;�@� ���5:���������7 � �5�7� 64�74 ��� �<� �75�� �@� �������� �@ �����6� � ;�����5 �@� � � :� 7����������e�,�2 4� ;������e���� ���4� ;�5����������������� � <�675:��;���4 �2���������� ����<���@� �� � :� 7�������e���� ,�2 4� ;��������������4� ;� 5����������������� � <�675:��;�� �� 7 ���7 � � �����<�7�7��@� � � :� 7�������g��������,�2 4� ;�5����������������� � <�675:��;��'5�����8�5��5:5�4���6 �<�@� � 6��:� 7��� 5�7��<�7�7�� �b45:����7� ;5������� 7 �� 2� 5 � �8� 7 ��< �:�5�5���9� f�7�< 56�� �8� 5��5:5�4��� 6 �<����<75���7 ��8����@5���8� 94����+5�� ��7���������������� � � ��� %�7� 6 �<<5����8���7�7��@57 �+ � 7�!4 �75���&���7�2�� � � / � ��� � ' <�n�'5�����8� ������7�7���7 ����� � '5a�n�'5�����8�5�7� 6 �<�oap��7 ������ � �<�n�+���5���< 56���8�<�7�7�� � �a�n�+���5���< 56���8�5�7� 6 �<�oap� � $ �� ���75:��;5����@� ��27�5����2;��5:5�5���7 ��5�7� 6 �<�;5�����8���6 �<�@57 �7 �� � <�675:�� ���� 6 �<� ;5���� �8� 7 �7� 6 �<� 7 �7� @� � ���<7��� 8 �9� !�@57� ���� &���� � �� � � ����e�� ���� 6��� 2�� �66�4�7���2;�7 ��8����@5���8� 94����� � � � !�7�����;5����6��7 52475���6 � �67� �@� �� �6� ����8 �9���� ����9�;� ���67���<���7 �8 �9���6 � <��7�����;5�����8�6 �< �@� �� �6� ����8 �9�@ ����<��7�2� 5 ��7� � :� 7��$ �� �6� ������7��@� �� 7�75 756���;� ����;3��� ���� 9���� :��4� � @� �� �<� �7��� 2;� 1+!� 8����@5��� .�9�3� ���� .�9�3� ���g��������7;<� ��8�:� 5�2���6� 7 ��8�< ��4675���@� �� �6� ��������6� 7�����2���857�����; 5 �@57 � � <�67�7����7� �74 ��@� �6� 5����47�7���:��4�7��7 ��< �857�25�57;��8��588� ��7�7 ��79��7 ��8�95a��� 5�7� 6 �<<5��� ; 7�9 �� ���� �� 4�7 �����!5 64 5���� 4�7 �����!5 64 5���� 4�7 �����!5 64 5���� 4�7 �����!5 64 5������ ���� *1$� 57��*�4�:52�3� *1$� 57��*�4�:52�3� *1$� 57��*�4�:52�3� *1$� 57��*�4�:52�3� ���� $@��;�� � � 4�7 � �:������7 �7�<�7�7��742� �����5�7� 6 �< �;5����@� �� 5��5856��7�;�5�8�4��6����4�� 7��95a���5�7� 6 �<<5����8�<�7�7��@57 �24 �2������� ����<������� ��5 ��$�2��������%����������� 7 �� 5� � 7�742� �;5�����8�<�7�7���������7� �����@� � �6� ����5�� ����<�7�7����� 4�7 �5��56�7���7 �7� 7 ��� ����<���;5�����8�24 �2�������ge�7� �����@� � �6� ���� 5� � �5��<�7�7������c��d�24 �2���� �e�c�� 5�7� 6 �<<5��� ; 7�9�7 ���95a��� 5�7� 6 �<<5��� ��8�<�7�7�� ����c��d�24 �2���� ��ec��d� �� ����<�����ec��d� ��5 ����c��7 ��79��7��+5��5856��7�:� 5�75�� �@� ���� ���2 � :����9����7 �� 7 ��79��7 ��8�95a���6 �<<5������ 7 ��;5��� ��8� �� ����<������� ��5 ��$ ��� ����<��� ;5�����8� �� ����<����e�g��7� �����@� �8�4��� 5� � �5��<�7�7������c��d��� ����<����e�c��5�7� 6 �<<5��� 7 ��79��7�7 ���95a���5�7� 6 �<<5�����8�<�7�7������c��d�24 �2������ec��d��� ����<�����ec��d� ��5 ����c���05� � �;5�����8� ��5 ��������7� �����@� � �6� ����5��<�7�7������c��d� ��5 ��e�c�� 5�7� 6 �<<5���7 ���<�7�7������c��d�24 �2������ec��d��� ����<�����ec��d� ��5 ����c��95a��� 5�7� 6 �<<5��� ; 7�9��$ �� 5� � �;5��� ��8�24 �2������� ����<������� ��5 �95� 7�2���4��7��7 �� 5� � � �75�� �8� <���7� <�<4��75��� 5�� 7 �5 � 5����� � �65�75�� � @57 � <�7�7�� 7 ��� 95a��� 6 �<<5��� ��7���7 � ��8�7 � ��:���7�2�� �@57 �<�7�7��� ��7 ���7 � � �����5�����������;5�����8�<�7�7���24 �2������� ����<������� ��5 �@� �� �@�� 5��5856��7� :� 5�75�� � �9���� 7 �� 7 ��79��7 � �8�95a��� 6 �<<5��� �$�2��� ���� $ ��9�a5949� 742� � ;5�����8�<�7�7���������7� �����@� ��27�5����5�� ����<�7�7������c��@ 56 �@� � 7�75 756���;�5���756��� @57 �<�7�7������c��d��� ����<����e�c���$ ��5�7� 6 �<�;5��� ��8�24 2���������� ����<�����e�� ���������7� ����@� ���27�5����5��<�7�7������c��d�24 �2�����e�c������<�7�7������c��d��� ���� <����e�c��5�7� 6 �<<5���7 ��79��7 �� � <�675:��;�7 �7�@� �� 5� � �7 ���7 �7��8�<�7�7������c��d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 � ���c�� 95a��� 6 �<<5��� 7 ��79��7�� � 15f�@5 ��� 5� � � 5�7� 6 �<� ;5���� �8� ��5 � �����e� 7� ����� @� � �6� ���� 5�� <�7�7�� ����c�� d� ��5 � �e�c�� 5�7� 6 �<<5��� ; 7�9� 6�9<� ��� 7�� <�7�7�� ����c�� d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 ����c��95a���5�7� 6 �<<5����� ��� + � �2��7����� $�2������'5�����8�<�7�7���5�7� 6 �< ���b45:����7����� ���75:��;5�����8�<�7�7��� ��88�67���2;�95a��� 5�7� 6 �<<5���@57 ��7 � �:���7�2�� ��7�*�4�:52�3� ������������ $ ��79��7 � ��7�7���7� ����� %�7� 6 �< ��7� ����� ��7�7��;5���� ����� ��� ����� ��� *���� ����� ��� ����� ��� *���� )b45:����7� �7 ����� ����75:��� ��7�7�� ��������c�� ������ ������ ������ �� �� �� � � ��7�7������c��d��4 � 2�����e�c�� �g���� �g��e� �g�g�� ��ge� ��e�� ���g� ������ ��ge� ��7�7������c��d�� .� ����<����e�c�� ������ ������ �g��e� e�g�� ����� ����� ������ ��g�� ��7�7������c��d�� ���5 ��e�c��� �g���� �g���� �g���� ������ ����e� ������ ������ ��g�� ��7�7������c��d��4 � 2������ec��d�.� ���� <�����ec��d�� ���5 ����c�� ������ � ������ ����e� �� ����� ���e� ���g�� �� ��g�� ����� g�g�� �� ����� ��e�� ���g� ���e�� ����� 1+!����e�� ����� ����� ����� �� �� �� � � #&��c�� ������ ���e�� ����� �� �� �� �� �� q� 56���8��47<47��$f��� 56���8��47<47��$f��� 56���8��47<47��$f��� 56���8��47<47��$f��?�?�?�?��������������������7�7������ ��������. ����<����8��4 �2��������.� ����<�������������5 �g� � �� 4�7 � �:������ 7 �7� 7 ��9���� ;5���� �8� <�7�7�� @� � �2 � :��� 9�a5949� ������� 7� ����� 5�� ���� <�7�7�� ����c�� 8����@��� 2;� <�7�7�� ����c�� d� 24 � 2���� �e�c�� 5�7� 6 �<<5��� ; 7�9� ��g�g�� 7���� ������$ ��9����5�7� 6 �<�;5��� ��8�24 �2��������g�7� �������� ����<���������7� ���������� ��5 � ������� 7� ����� � @� �� �6� ���� 5� � � 5�� <�7�7�� ����c�� d� 24 � 2���� �e�c��� <�7�7�� ����c�� d� �� ���� <��� �e�c�� ���� <�7�7�� ����c�� d� ��5 � �e�c�� 5�7� 6 �<<5��� ; 7�9�� � <�675:��;�� $ �� ��@� � ;5��� � �8� 7 � �� 5�7� 6 �< � ;5���� ���������e����������g� 7� �����@� �� �66�4�7��� 5��<�7�7�� ����c��d�24 �2������ec��d��� ����<�����ec��d� ��5 ����c��95a���6 �<<5���7 ��79��7��$ �� ��@� �;5��� �5��95a���6 �<<5����8�8�4 �6 �< �95� 7�2���4��7��7 ����@� �<� 6��7�����8�7 ��<���7� <�<4��75�� �� 5� � � 6�9<�7575��� �9���� 7 �� <���7 � 8� � �47 5��7 ��@�7� �� �5� 7� ���� �7 � � ��74 ��� � �4 6� ���� 4�7 � 5��56�7���7 �7� 7 �� 5� � 7�<�7�7���b45:����7�;5���� �������7� �����@� �8�4��� 5�� <�7�7������c��d� ��5 ��e�c��5�7� 6 �<<5��� ; 7�9�7 �7�@� �8����@���2;�<�7�7������c��d�24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 � ���c��95a��� 6 �<<5��� 7 ��79��7� @ � �� 7 �� <�7�7�� �b45:����7� ;5���� @� � ���e�� 7� ���� �$�2��� ���� 0�@�:� �� 7 �� ��@� 7� <�7�7�� �b45:����7� ;5���� @� � �64 ��� 5�� ���� <�7�7�� ����c�� 7 ��79��7� ���� 57� @� � ���;� ������ 7� ����� $ �� � 4�7 � � �� 5�� �� ��9��7�@57 �+� f� ��7����� �������@ �� �<� 7���7 �7����� 7 �� 5�7� 6 �<�6�925��75�� ��8�9�53�� 5�7� 6 �<� @57 � � 7� �4 �75��� :���7�2�� � �5f�� ��� �9� ��7 �� 24 � 2���� ���� �� ���� <��� @� �� < �:5���� 5� � � 9�53�� �b45:����7� ;5���� 7 ��� ���� 9�53�� 6 �<<5���� ����75:�� ;5���� ��7� 95�� � 6�9<�7575:�� �25�57;� �8� 6�9<����7� 6 �< � 5�� 5�7� 6 �<<5��� ; 7�9��. ��7� � :��4���8� ���75:�� ;5���� �@���9� ��6�9<�7575:���25�57;� 5�� 5�7� 6 �<� 574�75��� 7�� 57 �9���64�74 �� ��4 f5@��7�������������� 0�@�:� �� 7 �� ���75:�� ;5��� � �8� <�7�7�� @� �� ��ge�� ��g��� ��g�� ���� ����� @ ��� <�7�7�� @� � 5�7� 6 �<<���@57 �24 �2������� ����<������� ��5 �� � <�675:��;� �$�2�������$ 5 � 5��56�7� � 7 �7� <�7�7��;5����@� � ��46���2;��e���������������c��8� ���� 6 �<�@ ��� 57�@� � 5�7� 6 �<<���@57 � 24 � 2����� �� ���� <��� ���� ��5 �� � <�675:��;�� $ �� ��@� � ���75:�� ;5���� �8� <�7�7�� 5�� 5�7� 6 �<<5���5��56�7���7 �7�7 ��6 �<�8�6���6�9<�7575���8� � <�6����47 5��7 ���5� 7�����@�7� �@57 � �7 � �:���7�2�� ��$ ��85��5�� �� ��5���� ��9��7�@57 �7 �7��8�+5�� �������������� 9������������ ���� ,+�!� 57�������<4 ��+�47 �+4 9���+;� �7,+�!� 57�������<4 ��+�47 �+4 9���+;� �7,+�!� 57�������<4 ��+�47 �+4 9���+;� �7,+�!� 57�������<4 ��+�47 �+4 9���+;� �7���� �� 4�7 � �2 � :��� 7 �7� 742� � ;5���� �8� <�7�7�� ���� 5�7� 6 �< �@� �� 5��5856��7�;� 5�8�4��6��� �4�� 7�� 95a���5�7� 6 �<<5���@57 �24 �2������� ����<������� ��5 �� � ����6 �<<5����$�2�������%������� ��� %�7� 6 �<<5����8���7�7��@57 �+ � 7�!4 �75���&���7�2�� � ���� 7 ��9�a5949�742� �;5�����8�<�7�7�� �������7� �����@� � �6� ���� 5�� ����<�7�7�� ����c��7 �7� @� � 8����@��� 2;� <�7�7�� ����c�� d� 24 � 2���� �e�c�� 5�7� 6 �<<5��� ����g�� 7� ����� 7 ��79��7�� ��7@����7 ��7 ��79��7 ��7 ��9�a5949�� ����<���;5�����8�24 �2�������g��7� �����@� � �6� ���� 5��<�7�7������c��d�24 �2�����e�c��5�7� 6 �<<5���7 ����95a���5�7� 6 �<<5����8�<�7�7������c�� d�24 �2������ec��d��� ����<�����ec��d� ��5 ����c��7 ��79��7��+5��5856��7�;� 5� � �� ����<��� ;5���� �8� �� ���� <��� �e�e�� 7� ����� @� � �6� ���� 5�� <�7�7�� ����c�� d� �� ���� <��� �e�c�� 5�7� 6 �<<5���7 ��79��7�7 ���95a���5�7� 6 �<<5����8�<�7�7������c��d�24 �2������ec��d��� ���� <�����ec��d� ��5 ����c���/ 5����5��6� ���8� ��5 �� 5� � �;5�����������7� �����@� � �9� f���5�� <�7�7�� ��5 �5�7� 6 �<<5���7 ���<�7�7������c��d�24 �2������ec��d��� ����<�����ec��d� ��5 � ���c��95a���5�7� 6 �<<5���7 ��79��7��$�2�������� � $�2������'5�����8�<�7�7���5�7� 6 �< ���b45:����7����� ���75:��;5�����8�<�7�7��� ��88�67���2;�95a��� 5�7� 6 �<<5���@57 ��7 � �:���7�2�� ��7�+;� �7����������� $ ��79��7 � � � � ��7�7���7� ����� %�7� 6 �< ��7� ����� ��7�7��;5���� ����� ��� ����� ��� *���� ����� ��� ����� ��� *���� )b45:����7� �7� ����� ����75:�� ��7�7�� ��������c�� ������ ������ ������ �� �� �� � � ��7�7������c��d��4 � 2�����e�c�� ���g�� ����g� ������ ��g�� ��e�� ����� ������ ��g�� ��7�7������c��d�.� ���� <����e�c�� ���e�� ������ �g��e� e�e�� ����� ��e�� �e��e� ��g�� ��7�7������c��d����5 � �e�c��� �g���� ������ ������ ������ ������ ���� g� �e���� ���g� ��7�7������c��d�� �4 �2�����ec��d�� .� ����<�����ec��d�� ���5 ����c�� ������ ������ ���e�� �� ����� ����� ����g� �� ����� ������ ����� �� ����� ����� ������ ������ ����� 1+!����e�� ��e�� ���e� ����� �� �� �� �� �� #&��c�� e�e�� ����� ���e� �� �� �� �� �� q� 56���8��47<47��$f��?�q� 56���8��47<47��$f��?�q� 56���8��47<47��$f��?�q� 56���8��47<47��$f��?��������������������7�7������ ��������. ����<����8��4 �2��������.� ����<�������������5 �g� � �� 7 ��6��7 � ;�� 5����������� 7 �� 5� � 7� 742� �;5�����8�<�7�7�� ������� 7� �����@� ��27�5����2;� <�7�7�� ���� ����c�� 7 �7�@� ��� �� 8����@���2;�<�7�7�� ����c��d�24 �2���� �e�c�� 5�7� 6 �<<5��� �����g� 7� ����� 7 ��79��7�� $ �� ��@� 7� 742� � ;5���� �8� <�7�7�� ������� 7� ����� @� � 8�4��� 5��95a��� 5�7� 6 �<<5��� �8� <�7�7�� ����c�� d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 � ���c�� 7 ��79��7�� !4 5��� �������� 5�� 7 5 � ��6�75���� 7 �� � 4�7 � �2 � :��� 7 �7� 7 �� 5�7� 6 �<� ;5��� � ���� ;5�����77 5247� ��8�24 �2������� ����<������� ��5 ��588� ��� 5��5856��7�;��9����7 ��7 ��79��7 � �$�2�������0�@�:� �� 7 ��9�a5949�� ����<���;5���� ���e�� 7� ������8�24 �2����@� � �6� ���� 5�� <�7�7�� ����c�� d� 24 � 2���� �e�c�� 5�7� 6 �<<5��� 7 ��� <�7�7�� ����c�� d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec��d� ��5 � ���c��95a��� 5�7� 6 �<<5��� 7 ��79��7�� +5��5856��7�;�� 7 �� � ���� <��� ;5���� ������ 7� ����� �8� �� ���� <��� @� � �27�5���� 5� � � 5�� <�7�7�� ����c�� d� �� ���� <��� �e�c�� 5�7� 6 �<<5��� ; 7�9� 7 ��� 7 �7� �8� <�7�7�� ����c�� d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 ����c��95a���5�7� 6 �<<5���7 ��79��7���47��5��6� ���8� ��5 ��7 �� 5� � �;5�����������7� ����� @� ���756��� 5��<�7�7�� ����c�� 5�7� 6 �<<���@57 � ��5 � �e�c��7 ���<�7�7�� ����c��d�24 �2���� ��ec��d��� ����<��� ��ec��d� ��5 � ���c��95a��� 5�7� 6 �<<5���7 ��79��7��,4 7 � 9� ��� � 4�7 � 5��56�7��� 7 �7� 7 ��9����;5�����8�<�7�7���8���������������������@� � 7 ��9�a5949� ������� 7��� �����5�� ����<�7�7������c��8����@���2;�<�7�7������c��d�24 �2�����e�c��5�7� 6 �<<5��� ; 7�9� �������7� ������$�2�������$ ��9����5�7� 6 �<�;5�����8�24 �2����������7� �������� ����<������e��7� ��������� ��5 ������g�7� �����@� �� �6� ���� 5� � �5��<�7�7������c��d�24 �2�����e�c���<�7�7�� ����c�� d� �� ���� <��� �e�c�� ���� <�7�7�� ����c�� d� ��5 � �e�c�� 5�7� 6 �<<5��� ; 7�9�� ��� + � �2��7����� � <�675:��;�� $ �� ��@� � ;5��� � �8� 7 � �� 5�7� 6 �< � 5��95a��� 6 �<<5��� ; 7�9 � ������� ����� ���� ������7� �����@� �� �6� ����5��<�7�7������c��d�24 �2������ec��d��� ����<�����ec��d� ��5 � ���c��95a��� 5�7� 6 �<<5��� 7 ��79��7��$ 5 �95� 7� 2�� �4�� 7�� 7 �� ��@� �<� 6��7�����8� 7 ��<���7� <�<4��75�� �7 �7� � 4�7 �5����@� ��492� ��8�742� �����<�� �<� �<���7�������@� ��492� ��8� ��5 � <� �4�57�� ���� 5� � �6�9<�7575����9����7 ��<���7 �8� ��47 5��7 ��@�7� �� �5� 7������7 � ���74 ��� � �4 6� ���� �� 6 � � 4�7 � �:������7 �7�7 �� 5� � 7��b45:����7�;5�����8�<�7�7����e����7� �����@� � �9� f���5��<�7�7������c��d� ��5 ��e�c��5�7� 6 �<<5��� ; 7�9�7 �7�@� � 7�75 756���;�8����@���2;� <�7�7�� ����c�� d� 24 � 2���� ��ec�� d� �� ���� <��� ��ec�� d� ��5 � ���c�� 95a��� 5�7� 6 �<<5��� 7 ��79��7� @ � �� 7 �� <�7�7�� �b45:����7� ;5���� @� � ������ 7� ���� �$�2������� 0�@�:� �� 7 �� ��@� 7� <�7�7�� �b45:����7� ;5���� @� � ��5���� 5�� <�7�7�� ����c�� ���� �$��� 7 ��79��7� ������� 7� ������ $ �� 85��5�� ��8�7 �� 74�;�� ��5���� ��9��7�@57 �*4 �99���������������+���9��7�������������� +74�;��8� ���75:��;5����5��+;� �7� �:������7 �7�7 �� ���75:��;5��� ��8�<�7�7��@� ����g�����g������g�� �����@ ���<�7�7��@� �5�7� 6 �<<���@57 �24 �2������� ����<������� ��5 �� � <�675:��;��$�2��� ���� $ 5 � < �:5�� � 7 �7� <�7�7��@� � ��46��� 2;� ���� �g�� ��� ������c� �8� ���� 6 �<�@ ��� 57�@� � 5�7� 6 �<<��� @57 � 24 � 2����� �� ���� <��� ���� ��5 �� � <�675:��;�� $ �� ��@� � ���75:�� ;5���� �8� <�7�7�� 5�� 5�7� 6 �<<5��� ; 7�9� 5��56�7��� 7 �7� 7 �� 6 �<� 8�6��� 6�9<�7575��� 8� � <�6��� �47 5��7 �� �5� 7�����@�7� �@57 �:���7�2�� ��$ �� 85��5�� �� �� 5���� ���� ��9��7�@57 � 7 �7��8�+5�� � �������� �� 9��������������+� f� ��7�������������%�����575����:� ;��577����588� ��6��@� ��2 � :���2�7@���� 7 ����6�75�� ��0�@�:� ��57�@� �8�4���7 �7�7 ��<�7�7���b45:����7�;5����@� � 5� � �5��+;� �7�������� 7� �����7 ���7 �7��8�*�4�:52�3� �����e��7� ������$�2�������������� � � � � �� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � ! " � # $ % � " & � ' � � � � � � ( ) ) * � � � � � � � � � � � � � � + � ) � , ( % � , �, * + �� � �& � '� � � � � � � . � + � ) � , � ' � � + � ) � , � ,5��� ��� *��7 �;� �:� ���� 7�7��� �5�8���� �99��� 9�a5949� ���� 95�5949� 7�9<� �74 � ��4 5���<� 5����8�����������5��+;� �7� ���� #� 7�����2���857�����; 5 #� 7�����2���857�����; 5 #� 7�����2���857�����; 5 #� 7�����2���857�����; 5 ���� #� 7� 2���857� ����; 5 � �8� 7 �� <�7�7�� 9���� �b45:����7� ;5���� �8� �������� ���� �������� 5�� *�4�:52�3� � �:������ 7 �7� 7 �� � � � �74 �� �.��� �$f�� ���������� ���� ��7� �74 �� �(��� �$f�� ���e�����������2���857�6� 7� �75����#������e���@� �� �6� ����5��<�7�7������c��5�7� 6 �<<���@57 �� ��5 � �e�c�� 5�7� 6 �<<5��� ; 7�9� �$�2��� ��� ���� 7 5 � @� � 8����@��� 2;� 7 �� 7 ��79��7� �8� <�7�7�� ����c��95a���5�7� 6 �<<���@57 �24 �2������ec��d��� ����<�����ec��d� ��5 ����c���.���(�� �����#��@� ��$f�����e���������$f���������e����������� � <�675:��;���+595�� �7 ��� �@� ���� �� ��756���5��+;� �7���6�75���@ � ��7 �� 5� � 7�� � � �74 ���$f��e���������7� �74 ���$f�����g������ �e� %�7� 6 �<<5����8���7�7��@57 �+ � 7�!4 �75���&���7�2�� � �����#���������@� ��8�4���5��<�7�7������c��5�7� 6 �<<���@57 � ��5 ��e�c��8����@���2;�<�7�7�� ����c��95a���5�7� 6 �<<���@57 �24 �2������ec����� ����<�����ec������ ��5 ����c��7 ��79��7� �$�2�������%�7� � 75���;��7 ����@� 7�� � �������7� �74 ��r��#��@� ��8�4���5�� ����<�7�7���7�2�7 � *�4�:52�3� � ���� �����<4 � ��6�75�� �� $ 4 �� ���5��� 6�925��75��� �8� ���c� <�7�7�� 5�7� 6 �<<��� @57 �e�c� ��5 �5 �< �857�2���95a���5�7� 6 �<<5��� ; 7�9�7 �7�5 �< �:5����7 �� 5� � 7��b45:����7� ;5�����9���7� ;���:��7���������#���� � $�2��� ��� #� 7� ���� 2���857� ����; 5 � �8� 95a��� 5�7� 6 �<<5��� �8� <�7�7�� @57 � �7 � � :���7�2�� � �7� *�4�:52�3� �����+;� �7���������� $ ��79��7 � *�4�:52�3� � +;� �7� .�� �$f�� ����� $#� �$f�� ����� (�� �$f�� ����� �#�� .�� �$f�� ����� $#� �$f�� ����� (�� �$f�� ����� �#�� ��7�7�� ��������c�� ����e�� ��e���� ����e�� ����� ���ge�� ��e���� ��g�e�� ����� ��7�7������c��d��4 � 2�����e�c�� ������� ��g���� �e����� ����� ����e�� ��g���� �eg�e�� ���e� ��7�7������c��d� .� ����<����e�c�� ����e�� ���e��� �e��e�� ����� �e�e��� ���e��� ������� ����� ��7�7������c��d� ���5 ��e�c��� ������� ��e���� ��e���� ��e�� �e����� ��e���� ��g���� ����� ��7�7������c��d��4 � 2������ec��d�.� ���� <�����ec�d�����5 � ���c�� ��e���� �����e� �����e� ����� ������� �����e� ��g��e� ��g�� q.��. � � �74 ���$#�$�7���6� 7��(��(�7� �74 ����#������857�6� 7� �75��� � 56���8�5�<47��$f��f����� � 56���8��47<47��$f��f����� ��7�7�� ���������� ��7�7������ ������� �4 �2��������.� ����<��� ������� . ����<����8��4 �2��������� ���5 � ��������� . ����<����8�.� ����<������ " ������ ���5 �g� $+����� � * ���e� � .;< 49���� � m5�6�+4�< �7������ � � #��6�4 5��#��6�4 5��#��6�4 5��#��6�4 5������ ���� , �9�7 ���2�:�� � 4�7�57�9�;�2��6��6�4����7 �7� ���5���6�925��75����8����c�<�7�7��@57 �e�c� ��5 �95� 7� 2��< �857�2���95a��� 5�7� 6 �<<5��� ; 7�9� 7 �7� �88� � 7 �� 5� � �<�7�7�� �b45:����7� ;5�����9���7� ;���:��7�����8�7 ��8� 9� �����7 �7��� ������ �7���5:� 585���:���7�2�� �< ��4675��� � �@����� �5�6 �� ���6 �<<5���5�7�� 57;��� ���� ��8� ��6� ��8� ��6� ��8� ��6� ��8� ��6� ���� �f������*��)������*�����i4�;;49����g���)88�67��8� 5�7� 6 �<<5���94��2�����2��6f� �9�� �;2����� 6�@<��������� �4���47�@57 �9�53����������� ������ 5����� ��������������� ���9��*��+���*��(��% ��9�����1��(�����*��*��0�@���� �����*�����0� �5���������%�7� 6 �<<5������75�� @57 � 94f 5f�6 4� �#����6� 5�� � 64���7��� �7� �588� ��7� <���75��� ; 7�9 �� �������� � ��� �� 5��� �� ������������������ ��� + � �2��7����� ���9��*��+���(��?����4��� ����*�����i4�;;49�����g���� 8� 9��6�� �8� ;2 5��9�53�� �m���9�; �1��� 4��� �5�7� 6 �<<5��� ; 7�9 �@57 �94��2�����&5���� ��5�7��1���5���588� ��7�<���75���9�7 �� �� +���#������ 5�����������g��� �� �f��(��#���+��*�����0� �5���%��% ��9�����(��%��� 4;����������%�7� 6 �<<5���@ ��7�@57 �� �4���47� �7�:� 5�2���<���7�<�<4��75����������� ������ 5����� ���������������e�� !�@57��#��$������������&���� ��� � �����e��#�9<�7575���2�7@���� � 2����<���7 ��(�7 ������� 56�� +65��������������� .�9�3�?���������������.�9�3����g���+7�75 756���< �6��4 � �8� ��� 564�74 ����� �� 6 ������������� �� /5��;�����+�� ��(�@�'� f��<������� 0� �5���*������������?��*������� 5��������)88�67��8�5�7� 6 �<<5���� �4���47�@57 ��� �56��7�:� ;5��� <���7�<�<4��75�����:�� ���������� �0� 7������r����������� �4 f5@�����)��� ���0��0��59�����!��,��+��9����������#�9<�7575:�� �25�57;� 5��95a74 � � �8� 9���� � �5�� 6� ��� ��# �<�+65�������e������� *� ����� ��� ��� ����/��/5���;�� ��g��� ���5�75��� 5�7� 6�<75��� ���� � �@7 � 5�� ��� 5�7� 6 �<� �8� <�� �� 95���7l� �4���47��,5����# �< ��� �������������� *4 �99���� +�� $�� ������ )6���956 � �8� % 5��7��� � 5 � ,� 95��� 5�� *����� . � ������ '�2�� 7�7��� (5�� 5��� �� *�+6�� !5 � 7�75��� �4�<42�5 ����� !�<� 79��7� �8� �� 564�74 ��� )6���956 � ���� )a7�� 5����,�64�7;��8��� 564�74 ���"�5:� 57;��8�*�5�4�4 5���� ��� 7�7��� ��7 56f��!��#������*��1��*������������+74�;����7 ��<� 8� 9��6���8�6 �<����49��4��� �9���64�74 �� ����5�7� 6 �<�6�925��75����+5a7 ����4���*�53��!�:���<9��7�/� f �<��(�<���� �� 9����*�����������#�9<� �75:��<� 8� 9��6���8�5�7� 6 �<<5���5��<4� �������5�� ��� �@57 � �5�8��� @ ��7��$ 575649��� 75:49��5���������� ��%��5�������� ������������e���e�g�� ��33�b4���*������+����85b433�9����*��*����33�3��*�������5�����*��*�����$��4f�� ��������+74�;���� 7 �� 5�7� 6 �<<5��� � �4���47� @57 � 6 5��5� �7� �588� ��7� <���7� <�<4��75�� �� �������� � ��� �� 5��� �� ���������������� +���9��������'������&��?@�� ��������� %���3� �����������+74�;���� ���75:��< �857�25�57;��8� �������� 95a��� 6 �<<5��� ��7� < 5 � � �9���� 9��� ���� � 5 5��75��� 8� 9� � 5�� 7 �� 0���j5��(�4 4� /�7���� ��8�(� 7 �� 7� ��(5�� 5���.��2����� ������� 5����5����+65����������������� +� f� ��"��?���+��!�;��+��?4��4�����*������@���������� ��8� 9� 74�;���� 5�7� 6 �<<5����8� ;2 5�� 9�53��@57 � � 7��4 �75���:���7�2�� ������������� ��� 5���"�5:�������������� +5�� ��#��&������?��+5�� �����&��+��# �4 ��������������75:��<� 8� 9��6���8�<5����<�������7;<��5�� �������� 56��5�7� 6 �<� ; 7�9 ��%�7����5����<���(�@ �������������� +5�� �����&�� ������� ��4675��� <�7��75��� ���� �6���956 � �8� :���7�2�� �@57 � �5�8��� f ��� %��5��� ��� 0� 7��e�������������� '� �6f�� ��� '�� ������ # �< � ���� 6 �<<5��� <�77� �� �8� 7 �� +�:����� ��5��� �8� (5�� 5��� $ �� ?��4��� 574�75���� ��<� � < � ��7��� �7� 7 �� 5�7� ��75����� 5�7� 6 �<<5��� @� f �<�� ���4� ;�� ������� ������%#�%+$��0;�� �2����%��5��� microsoft word final.doc � �������� ��� �������������������������� ���� !��"#�$%&'#��(��!&� �)��%& %&*�+"#&����%*&#���� !��"#�$%&'#��(��!&� �)��%& %&*�+"#&����%*&#���� !��"#�$%&'#��(��!&� �)��%& %&*�+"#&����%*&#���� !��"#�$%&'#��(��!&� �)��%& %&*�+"#&����%*&#�������� ���� �&#�*$* &,�&#�*$* &,�&#�*$* &,�&#�*$* &,���� ���� ,��%��!� �-�,��%��!� �-�,��%��!� �-�,��%��!� �-�������,�����%��,�������,�����%��,�������,�����%��,�������,�����%��,�����������������"��.��#���� /�"��.��#���� /�"��.��#���� /�"��.��#���� /�0000��,�����!�1-/��,�����!�1-/��,�����!�1-/��,�����!�1-/������������,�����% ��/����,�����% ��/����,�����% ��/����,�����% ��/2222�������� �*��-� �*3-��4-5-3��55-3� �2*3-��4-5-3��55-3� �����-������ ��4��� �� 3 �.��4 ������%����6 � -� �#�34� ����� ������������ ��� -37�47 ����� �� 3 �%� 4-474�����8��9:7 ����;-:7 � 0. -�5�*3-��4-5-3��55-3� ��*��-� �*3-��4-5-3��55-3� ��� ��4��� �� 3 �.��4 �����;-:7 �<�#-��6:7 � .� � :���-����74 � ��-�-� = 3>�/�-��3�/� � ?�8�=� � ��?�8�=� � ��?�8�=� � ��?�8�=� � ��� �=4 ��8-�����= ��4�@� -�4-� �� ����9��� 8 4�/���� ���� �9 4 �34�9 4 �34�9 4 �34�9 4 �34���� ���� ��4=��8�� ��a:� -/��4�=� �3���734����7 -�����9-� �� ����5�������0��������0�����4� 4 �� ���-����� � ��4� �� �� 3 � .��4 �� ����.��� �������� � �� -37�47 ��� �� �� 3 � %� 4-474�����6 � -����3��4�8� ���� ��� -a�@� -�4-� ��-1��* �4�9�-���-6�8��b ��-:�����%���/� �2�� ���%� ��/� ��� ���� ���%� ��/� ��� =� �� �@��7�4��� 7��� � ���� 9��� 8 4�/� -�� ����/-;���3�/:��4��9��31��� -���=-4 � 4 ��� �:�-3�4-�� �� ��@� -�4-� �=� ���@��7�4��� 5� � 8-����� ���� 8-���� 3�/:����4 �=-4 � �/��: ������-3��� ����: 8 -����-3��� :� �/�4� �� ���55�34 ��5� ����9��� 8 4�/��@� � 4=��8�� �=� �� -��-5-3��4� 5� ����� 4 ��:� �/�4� �� �� -� � 4�/����8-�����@� �4-������/�4 �����/����4 ��4� 4���@� -�4-� ��=� �: ��73���98� @� -�4-� � ���%� ��/� ��� ���� * �4�9�-� 5����=��� 98� ���%� ��/� ��� ���� �-6�8� @� -�4-� �� � �� @� -�4-� � : ��73��� �45�34� 8� 8-��� � -�� ���� 9���/�4 �� �� �� ��=� 4� 8-���� � @� -�4-� �=� ��b ��-:��������%���/��2��.�� -�� -���4 ���@� ����� �=4 ��8-���������4 � � 3 � �34� � �5� 4 ��� @� -�4-� � �-1�� ���%� ��/� ���� * �4�9�-� ���� �-6�8� �@�� 9���� : �@-�����8� ���34����4���6 � -� ��-���� �=����� �-��= ��4�� �=-���� �� �-���������� ���� ���� %�4 ��734-��%�4 ��734-��%�4 ��734-��%�4 ��734-������ ���� ����/����5� ��5����: ��734-���-���������� ��-�3 �� -�����8�98���8�4��5����4 ��-�3 �� -��� :�:7��4-���-��4 ��3��4�a4��5����3 �� -���3 �:�������7��4��3�� 4 734��5� ����� �7 -��������4 � � -�5 � 4 7347 ���*�����=� -4� � 4 �� 4-/����/���� 4�� 3 �����74� 7-4�9���@� -�48��5�3� ���������4 � � /�6� �3 �: �����4�3 �����8�4��/��4�4 ��5������/�����,� 4��5�4 ��3� �����:7� �������4 � �3 �: � �@�� 4 ��-4-�����8� 9���� :���4��� �54� � 4 ��� :��7� -��� 5����=��� 98� ����� -��� = -3 � � ��=�� ��9� -�7 ��4-/��3�� 7/-��������� ��3� 4�8��*-�� �����0��� ��5� /� �� ��5�3-���4 �79���4��3� 8� �74� �� -37�47 ��� �:� �4-��� �7�� 4�� ��9� � � 4���� � :�3-���8� -�� 4 �� :-31� :� -���� -������ : �34-3� � 3��4 -974�� � ��4�8� 4�� 4 �� ��9� � 3� 4� -����8�3 �:�: ��734-��� 8 4�/� � 7�4-��� -�� ��=� ��3���/-3� �47 � ��'-/����4�������������(� /� �-��%���������4-3�b��-� ��%�b���5�%��-��� ��8�4�4��� �=�/�-;�� 7��� � �� ��79��� ���4-��� 8 4�/� �-4 � � ��� 4 �� 5��4� � � ���� 9�� �� ��4 �7� � 4 � �� � �� 3�//��� : �34-3� � -�� /��8� =� 4� �� 3�7�4 -� � ��7:4�� �4� ����� ������� ���73��� � � 3�� � @�4-��� 4-������ � ��-�-��� /� �� �44��4-��� -�� �3��4� 8�� � =-4 � -�3 �� -��� 3��3� � � �9�74� ��47 ��� � �7 3�� ��� ���4-���� %�4�� -@�� 4-������ 8 4�/ � � 7�4� -�� -�3 �� ��� �-�� 3�/:�34-��� ���� ��3 �� ��� �-�� � ���-3�/�44� ��*-�� ��4���������2������9-��-@� -48����.�.%,,$ �����0���*79� �-��3�/:�34-��� �7�� 4�� �:��4��� 4-������ ���� � 4�� ��73��� =�4� � ���� �74 -��4� 7 �� �55-3-��38� ����� =��� ���� �� =�/-�����0���� .�� � @�4-���4-������: �34-3� �� 73 �� �;� ������/-�-/7/�4-�������/�8�9��-�4 ��73���4���55 �4�4 �� : ��734-��� 3� 4� ���� �4 � � 3�� 4 �-�4 � � �3-�4��� =-4 � ��@��/��4� ���� �3-���3���/-3� 3���-4-�� �������9���:���4-����5�/�-;�� ��: ��3 -�@�������:���4�� 4�9� /��4��-�3 �� � �-�:74� �55-3-��38��-�3 �� � �8-��� �������:�� �7:��@��7� �5� �����79������4-��� 8 4�/���-44��4������������� ��� !� �-���4����� ���a:� -/��4�=� �4 � �5� ��7��� 4�1���4�� ���34�4 �� 7-4�9���@� -�4-� �7��� � ����9��� 8 4�/� -��� �7� 4�: ����� ���� ���� ,�4� -�� �����,�4 �� ,�4� -�� �����,�4 �� ,�4� -�� �����,�4 �� ,�4� -�� �����,�4 �� ���� ���� �� 4 -��� =� � 3���734��� =-4 � �3��4�8� ���� ��� -a� = ��4� @� -�4-� � �4� 4 �� ���-����� � ��4� �� �� 3 � .��4 ��� ���%�� ��6 � -� -�� ������0� ���� ���0����� �� �a:� -/��4� =� � ��-�� �74� -�� ����/-;���3�/:��4��9��31��� -���=-4 �4 ��� �:�-3�4-�� ��*��� �=� �� �=��98�9���:���4� �=-4 � �2�/�4� ������a�����/�=-���=-4 �c� �= �5� � -a�@� -�4-� ���/��8�* �4�9�-��b ��-:���-6�8�����%���/� �2��������������� ��4��� �� 3 �.��4 �� �3�//������/�����/��4�: �34-3� �=� ��5����=���4�� ��� 4 �� 3 �:�=-4 � -��4-��� ���� �4 � � : �34-3� ��#�4��=� �� �3� ���� ��� �-55� ��4� �� ���/-3� :� �/�4� �� �=����� �: ������-3�������: 8 -����-3���3 � �34� 4-3 ���4�/�47 -48��5�7 � �= �=-4 � ��/� ����� :��4� -;�� =� �� � @� 4��� 4�� � 4-/�4�� � �-�� 8-���� �a: � ��� � � 4��� :� � �34� ��� �� 3����34��� ��4��=� �� ����8;���=-4 �. �:�*4�4�,����� ����/��� �=� �� 3�/:� ��� 98�,* � �.� /��������/�;�������/�;���dc����� ���� �� 7�4 �����#37 -���� 7�4 �����#37 -���� 7�4 �����#37 -���� 7�4 �����#37 -������ � � �=4 �:� �/�4� � �=4 �:� �/�4� � �=4 �:� �/�4� � �=4 �:� �/�4� ���� b ������-3��� ��4�� �5� -a� @� -�4-� � 7��� � ���� 9��� 8 4�/ � � �� : � ��4��� -�� �9��� ��� �� 7�4 � �@������ 4 �4� * �4�9�-� ���� ���%� ��/� ��� =� �� ��0� ��8 � ����8��� �@� � �4 � � @� -�4-� � 7��� � ����9��� 8 4�/ ��#�8 �4�� ���-������4 � �����: 8 -����-3���/�47 -48�=� ��0�����8 ��� �-� �-�� b ��-:�����%���/��2��������%���/����@� -�4-� �7��� � ����9��� 8 4�/��@� �* �4�9�-���-6�8� �������%���/����@� -�4-� ���(-����8� ����9��� 8 4�/ � -��-5-3��4�8�-�5�7��3���4 ��3 �:�� �=4 � �7 �4-������� � � � 7�4 �* �4�9�-���-6�8��������%���/����@� -�4-� �=� �� ����� � 3 �:��7 �4-��� �������0���8 ��3�/:� ���4��b ��-:�����%���/��2��������%���/�������2�������8 ����/���� 4 �� -a� @� -�4-� �� * �4�9�-� 4��1� /�a-/7/� 4-/�� �5� 9��4-����2� ��8 ��� ���-��� ���� ��8 �� ���� ��4 � � ��d� ��8 �� 5����=��� 98����%���/���� �����-6�8� ���� 4 � �� @� -�4-� � �������/�a-/7/� 4-/�� 5� �/�47 -48� ���0���8 ���,�a-/7/�9��4-��� 4-/��=� � �� �� 5�7��� 5 �/�* �4�9�-� @� -�48� 98� ��71�� � �4� ���� �������� �� �� �� �/-� 4�9���7�� 4��* �4�9�-���-6�8��������%���/����=� �� -� �8� �� -4-@��7��� � ����9��� 8 4�/ �=-4 ���4�/� ��9� �� ��55�34����� � �9������� �=4 �:� �/�4� ��5�= ��4�@� -�4-� �7��� � ����9��� 8 4�/ � )� -�4-� � #�8 �4�� 9��4-��� #�8 �4�� ���-��� #�8 �4����4 � � #�8 �4��: 8 -����-3��� /�47 -48� * �4�9�-� �2� ��� �d� ��0� �-6�8� ��� ��� ��� ���� b ��-:� �0� �0� ��� ��2� ���%���/��2� �0� ��� ��� ���� ���%���/���� �0� ��� ��� ���� ���%���/���� �2� �2� �d� ���� '*#�����2�� ����� ����� ����� ���0� .)��e�� ���� ��0� ���� ��c� � �4���� 8�/�44� �-�3 �� ���:f��2���=-4 �-�3 �� ���4 ���7 �4-���7:�4��� �-��5-��-��� 4�����/�������� 4 ��@� -�4-� �7��� � ����9��� 8 4�/ �����4 ��� ��=�8���3 �� ��� �(-�������,�a-/7/�� 8�/�44� � : ��734-���=� � -� � �-��* �4�9�-���-6�8��������%���/����@� -�4-� ��7��4��-4 �� �=4 ��7 �4-��� ������4 �/� ��9� �� ��55�34�����/-�-/7/�-�����%���/��2�����b ��-:�@� -�4-� ��7��4��-4 ����5� ��� 3��3������/747��� ��-������@�� 4 ��4������������5�7���/�a-/7/�� 8�/�44� �-��� �-��5-��-��� �0� $-�����5�� ��4�+��� ����������*8 4�/� 4���� 5 �/� /747��� ��-��� ����48:� � 7��� � ���� 9��� 8 4�/ �� '��5� � ��� -���a� -�3 �� ��� �:f������=-4 � -�3 �� ��� 4 �� �7 �4-���7:� 4�� 9��4-��� 4���� ���� 4 � �� �54� � ��3 �� ���7:� 4�� ��4�� � �-��5-��-��� 4�����,�a-/7/����5�� ���-���a�=� �5�7���5 �/����%���/�����* �4�9�-������-6�8� @� -�4-� ��7��4��-4 ������ ��7 �4-����������5� ��� 3��3������/-�-/7/�=� �b ��-:��������%���/� �2��������@� -�4-� ��(-�������!�99 ������7:4���������5�7���/�a-/7/����5�� ���-���a�-������� � �7 �4-���@� -�4-� �5 �/�9���:���4-��� 8 4�/�� � � ��� ��� ��� ��� ���� ���� ���� ���� ���� ���� ��� ����� � �� ���� �� ����� �� � �� ����� �� ��� ��� �������������� �� � ��� �� ! � � � � ����� ��� �� ����������� ����������� ����������� " "#$ % %#$ #$ & &#$ ' ��� ����� ���� � ����� �� � �� ����� �� �������� ����� � ��(���� �) � �����*�� �+�, � ���)������� $ )������� . )������� / � (-������ #,����@� -�4-� �7��� ���� 8 4�/ ���������(-������'�%����@� -�4-� �7��� ���� 8 4�/� ���� ��:�44� ���5� 3 �:�� �=4 � �4�� �=��� 4 �� -/-�� � 4 ���� -�� ���� 4 �� @� -�4-� � 7��� � ���� 9��� 8 4�/ � �(-��� 0��� �� 3 �:� � �=4 � �4�� �� :f��0��� -��-5-3��4�8� -�5�7��3��� 98� 4 �� : ������-3��� 4�����5�= ��4�@� -�4-� �7��� � ����9��� 8 4�/ �� ��3 �:�� �=4 � �4��� ��7���8�-�3 �� ���7:�4�� 9��4-���4�� ���-��� 4�����54� � �=-���-������4 ��@� -�4-� �����-4���3�-����5 �/� ���-���4��/�47 -48�� ?�4�1-� ������� 5�7��� /�a-/7/� 3 �:� � �=4 � �4�� -�� 9��4-��� 4�� ���-��� 4���� ���� ��=� � -�� : 8 -����-3��� 4���� 5 �/�9���:���4-��� 8 4�/������ ���8��4� ��4� �� �=4 � 4����� ����3�-����.��� 3�7 ��� 98� /747��� ��-��� ���� ���5� ��� 3��3�� ��73� � 4 �� : �4� 8�4 �4-3� �55-3-��38� ���� 7�4-/�4��8� ��73� � 4 �� � 8� /�44� � �337/7��4-��� �4�� �5� �� 3 �:�� '�7 ��� �4� ���� ������� 5�7��� /-�-/7/�3 �:�� �=4 � �4�� -��: 8 -����-3���/�47 -48� 4����7��� � ����9��� 8 4�/ ��,�a-/7/� 3 �:�� �=4 � �4��=� �5�7���5 �/�9��4-���4�� ���-��� 4��������-4�=� �7:���=��4�����38����4 � 4���� �54� � ���-��� 4���� -4�=� � 4 ��� ��3 �� -��� 7:� 4�� ��4�� � �-�� 5-��-��� 4����� *-/-�� � 5-��-�� � =� �� �� �� ��4� 98� ��71�� � �4� ���� �������� �� -� � 4� 3 �:� � �=4 � �4��=� � 5�7��� 5 �/����%� ��/� ���� * �4�9�-� ���� �-6�8� @� -�4-� � ���� ��=� 4� =� � ���%� ��/� �2� ���� b ��-:� @� -�4-� �� � �7��� 3�@� ���� -�3 �� �� =-4 � -�3 �� ��� 7:� 4�� 9��4-��� 4���� ���� 4 ��� ��3 �� -��� 7:� 4�� ��4�� � �-��5-��-��� 4�����,�a-/7/�� �7���3�@� ����=� ��� ��5�7���5 �/����%���/��������%���/� ��������-6�8�@� -�4-� �����/-�-/7/�=� �b ��-:��������%���/��2�@� -�4-� ��(-��������g7�887/� �4������������5�7�����/�a-/7/�� �7���3�@� ����5 �/��-6�8�@� -�48��@� �b ��-:�@� -�48�� � ���� � " " '" ." 0" %"" % " %" ��) � " ��) � &" ��) � � ��� � ��� �� � � �) ��� (�( �� ��� ���������(���� � � ��1 ! � � � � ����� ��� �� ����������� ����������� ����������� � (-���0��.������= ��4�@� -�4-� �7��� ���� 8 4�/ ���(-�������.��e�����@� -�4-� �7��� ���� 8 4�/ � ��� !� �-���4����� � �-��8-��������8-����3�/:����4 � �-��8-��������8-����3�/:����4 � �-��8-��������8-����3�/:����4 � �-��8-��������8-����3�/:����4 ���� � �-��8-�����4 ��37/7��4-@���55�34��5� :-1��/����� �-� � :-1�������������� �-��=�-� 4���@� ���� 4=�� 8�� � 8-���� ���� 8-���� 3�/:����4 � ��4�� =� �� �=�� -�� �9��� ��� ����� 9��� -��-5-3��4�8� -�5�7��3��� ��� � �-�� 8-���� ���� 8-���� �44 -974� � 7��� � �-55� ��4�= ��4� ����48:� � 5 �/� 4=�� 8�� � ��4��� ��/�a-/7/�� �-��8-����=� �5�7���������4� �����5 �/����%���/����@� -�4-� �����-4�=� � �4�:� �=-4 ����%���/���� ���2�� 4� ������* �4�9�-� ���20� 4� ����������-6�8� ����2� 4� �����@� -�48�� � �-��8-����=� � -� � ��7�� 4�� -� � �8-�����44 -974� ��� �=4 �:� �/�4� �����/� ��4-��� -������� 9� �� � �55�34�� ��71�� � �4� ���� ������� 5�7���/� �� 8-���� 5 �/�* �4�9�-� @� -�48� 7��� � ���� 9��� 8 4�/�� �4 � � @� -�4-� � : ��73��� 5�=� � 8-��� � �7�� 4�� ��=� � 8-���� 3�/:����4 � ���� � �=4 � :� �/�4� �� ��/-�-/7/�8-���� ������ 4� �����=� � 5�7��� 5 �/�b ��-:�@� -�48��7�� 4�� ��=� � 8-���� 3�/:����4 ������� �4-��� -����,-�-/7/�� �-��8-����=� ��� ��5�7���98� ��71�� ��4������������5 �/� : ��-:�@� -�48�7��� �9���:���4-��� 8 4�/��$-����3�/:����4 �=� �� -��-5-3��4�8�-�5�7��3����/���� 4 ��@� -�4-� �7��� � ����9��� 8 4�/��,�a-/7/� :-1��/����0d���=� �5�7���5 �/����%���/���� @� -�48� 5����=���98��-6�8� �02d������* �4�9�-� �020��@� -�4-� ��,�a-/7/� :-1�� ����4 � ������3/��� :-1���4� :-1���� ����0�� ����� �-� � :-1���� ����0�� 5�7��� 5 �/����%���/���� @� -�48� 5����=���98� * �4�9�-������-6�8�@� -�4-� �� ��71�� ��4������������5�7���/� �� :-1������4 �� :-1���4� :-1�������� � �-� � :-1���� 5 �/�* �4�9�-� �����-6�8� @� -�4-� ��,-�-/7/� :-1�� �0�d��� :-1�� ����4 � �d���� ���� � �-� � :-1���� ����� �94�-���� 5 �/� : ��-:� @� -�48�� ��71�� � �4� ���� ������� 5�7��� -/-�� � 5-��-�� � 5 �/�4 ���a:� -/��4 �7��� � ����9��� 8 4�/�� � �9������&55�34��5� �3��4�8� ���� ���= ��4�@� -�4-� ����8-����<�8-�����44 -974� �7��� � ����9��� 8 4�/� )� -�4-� � *:-1�� /��� *:-1������4 � �3/�� *:-1���4� :-1���� � �-� � :-1���� ��� ���� �@����8�� � 8-�����4� ����� * �4�9�-� 020� d�0� �d�c� ���0� ���0� ��20� �-6�8� 02d� ���0� �d��� ����� ����� ���2� b ��-:� 0�d� d��� �c�0� ����� ����� ����� ���%���/��2� 002� ����� �c��� ����� ���0� ����� ���%���/���� 0��� ���0� �c�d� ���0� 2��0� ��2�� ���%���/���� 0d�� ����� ���0� ���0� �2��� ����� '*#����2�� ���d�� ���2� 0���� c���� ����� ��2�� .)��e�� ���2� ����� ����� d��� d��� ���� � .��3�7 -��.��3�7 -��.��3�7 -��.��3�7 -������ ���� �� ��� ��� 4 �� �@� ���� :� 5� /��3�� �5� 9�4 � : ������-3��� ���� 8-���� ���� 8-���� �44 -974� � ��� -a� = ��4� @� -�4-� �� -4� =� � 3��3�7���� � 4 �4� * �4�9�-�� �-6�8�� ���%� ��/� ��� ���� ���%� ��/����� :� 5� /���4 ��9� 4�7��� � ����9���3���-4-�������4 ���4 � � �����b ��-:��������%���/��2� =� ��4 ����� 4�:� 5� /� �7��� � ����9��� 8 4�/��� ���� �31��=�����/��4�31��=�����/��4�31��=�����/��4�31��=�����/��4���� ���� ��� � �� @� 8� :��� ��� 4�� �31��=������ %�4� ��4-����� ,�-;�� ���� � ��4� %/: �@�/��4� .��4 �� �.%,,$ ���������� �5� �4 ��3� �-���3��:� �4-�������5-���3-���� 4��3��� ���� ���� ���� �2� $-�����5�� ��4�+��� ����������*8 4�/� ��5� ��3� ��5� ��3� ��5� ��3� ��5� ��3� ���� ���� ���� =����b��?����������� =�/-�����0������:���4-��� 8 4�/�5� �-�3 �� -����74 -��4 �����=�4� �7 �� �55-3-��38��5�= ��4�� �=�����%�3�:4���� 8:-3�+ 4�3 �:4���%��-�������� -���*3-��0��c������� �2�� ��/�;�� ?�� ��� ���� ��� ��� ��/�;�� �dc��� *4�44-3��� b �3��7 � � 5� � �� -37�47 ��� �� �� 3 � � �3���� ��-4-������� ���-��8�<�*�� ��%�3���%��%��b -�-::-�� ���c�:�� ��@�� 4 �� ���� ?�� #�� *�8 �� ���� ��� #�31� �� ������ �=� � � /-�-/7/� ��4�� �4 � 5� � �-�� h7��-48� � � /��4�� �� 3� ���5� ;� ��4-������= ��4i/�-;�� �4�4-�� � -�� 4 �� -� ������5�,�a-3���*�-�� -�������� �c�����0������ �7:4������?������?��"� � ��b�����!�99 ��������?��'�� ������������:4-���.�� � @�4-����� -37�47 �� -���-3��� ��4�*8 4�/ ��5�4 ��%���������4-3�b��-� ��"�=��::� 47�-4-� �5� �*�@-��������4� ��� b�:� �: � ��4��� �4� 4 �� j��4� �����-3��b ��734-����� 1 �:j��2������: -�� ������ %��%�� b -�-::-�� �� !�99 ��b������������?���7:4���������k*�-������. �:�,�����/��4�b �34-3� �5� �&� ��3���b ��734-@-48��5� 4 �� �-3��� ��4�. �::-��� *8 4�/� -�� 4 �� *-3 7��� b �@-�3�� �5�. -��l�� �-3��� ��4�.�� � 4-7/� b�:� �*� -� �d�����.��"�=�#�� -��%��-���� ?�4�1-��b��?�������� �� -3��= ��4�3 �::-��� 8 4�/�-��*�74 �� ��� ��.�� 4 �-�4 �����b ��734-@-48�� ��b ����7������. �:�b ����0�������� '�7 ��������������,��#7a97 8���,��%��!� �-�������*� ������*��,��!��,�� ��71�� �����.�����,��� �� ������ b� /����4� ���� 9��� 37�4-@�4-��� -/: �@� � �-4 ����� ���� =�4� � 7 �� -�� -3��= ��4� 3 �::-��� 8 4�/ ��5��*�74 �� -����c4 ��� ���*3-��3��.��� � ��+*��� '-/���� ��� ���� ?�� #�� *�8 �� ���� .�� ��� ( ��3�� ������ � ��4� ���� /�-;�� 8-��� � -�� � :�� �� 4����������� 4 �=�/�����/��4������-4 �����7��� ���9���:���4-��� 8 4�/���� �������d����d2�0���� g7�887/��,��������� -/ -����,�����!��*���� �������������7/�����#�����.���� ��������� �-��8-���� ���� 8 4�/� : ��734-@-48� 5� � = ��4�/7��9���� -3�� ���� = ��4�/�-;�� -3�� �h7��3� � -�� �� 4 � ���������� �� �-������ -3��*3-��02�����2������ ��.�.%,,$ �� ���0�� ��� � -��� �� �7 3�� .�� � @�4-��� % 7� � -�� �-3��� ��4� *8 4�/ � �5� *�74 � � -������� �7 3�����1����.�.%,,$ ��"�=�#�� -��%��-��� *-�� �� $�� ���0��. �:��� -�7��/�����/��4� -�� -3��= ��4� 8 4�/�� ���0�� %��� ��� � -����� �7 3�� .�� � @�4-���% 7� �-���-3��� ��4�.�� � 4-7/�5� �4 ��%���������4-3�b��-� ��.%,,$ ��"�=� #�� -��%��-���:��20�� *-�� �� $��� ��� *-�� � ���� ��� -/ -���� ���2�� . �:� � -�7�� /�����/��4� 5� � �74 -��4� 383�-��� ���� -/: �@-��� �-�� : ��734-@-48� -�� -3��9� ��� 3 �::-��� 8 4�/ � -�� 4 �� 4 �:-3 �� ��@���� ���� c2�� ��d������ ��71�� �����*��,��!��,���.�����,��� ��,�����?�9���������*��!� �-�������,��!� 7��7 ��� -��� ������ b ��734-@-48� �5�/7�4-�3 �: � �=�� ��� :� /����4� ���� 9�� � -�� 4 �� 4 �:-3 �� %��� "�=� #�34-��� 5� � �� #-@� �� b����4�� !���9��1� ���� �9 4 �34 � 5� � 4 �� �4 � %�4� ��4-����� . �:� *3-��3��.��� � ��� 9������7 4 ��-������*�:4�/9� ������34�9� �������:���0�� ��71�� �����*��,��!��,���,�����*75-�������.�����,��� ���������-3���= ��4�����/7��9����8-��� � -�� � :�� �� 4�� "� ��@�� � ���� /�����/��4� 7��� � �� 9��� :���4-��� 8 4�/�� %��� b �3���-�� � :79� ��� -�� 4 ����4 ��� ���.��� � ��5�*�-��*3-��3�������1�1�� �-�����@����*8/:� -7/� ��������:�02���� ��� !� �-���4����� �-44��.���?�����.� /����#��.����1��+���-1� �� � *��b�� '-9�����,�� %�� *�/ ��� ���� ��� .������44�=�� ������ . �:� �4�4-��� ���� � -�7�� /�����/��4� �55�34 � ��� 3� 9��� �h7� 4 �4-���� �-4 ����� 383�-�������: ��734-@-48��5�-��4��� -3�� 8 4�/ ��b���4�*�-�����2����0���c�� � bangladesh agron. j. 2015, 18(1): 65-70 salt induced changes in dry matter accumulation and yield of mustard (brassica juncea) m. m. zaman1, m. a. mannan2 and s. c. samanta3 1regional training coordinator, usaid agriculture extension project, jessore 2department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 3department of agronomy, patuakhali science and technology university, patuakhali-8602 corresponding author: mannanbsmrau@yahoo.com keywords: m ustard, salinity, irrigation water, dry matter, seed yield abstract the experiment was laid down to identify mustard [brassica juncea (l.) czern & coss] genotype tolerant to soil salinity in relation to shoot and total dry matter (root+shoot) plant-1, number of siliqua plant -1, number of seed siliqua-1, 1000-seed weight and seed yield plant-1. four genotypes (bd 9080, bari sarisha16, bd 9109 and bd 9107) were evaluated at three levels of nacl salinity, viz. 0 (normal), 50 and 100 mm. all of the mustard genotypes showed decreasing trend with respect to all of the above mentioned crop parameters with salinity over normal water and thee decreasing rate of the parameters was higher with the increasing salinity levels. among the genotypes, bd 9080 showed the best performance with respect to above mentioned characters at all levels of salinity, while bd 9107 performed the poorest. thus, genotype bd 9080 proved to be more tolerant to salinity than other genotypes. introduction mustard (brassica spp.) is one of the most important oilseed crops throughout the world after soybean and groundnut (fao, 2004). among the oilseed crops grown in bangladesh mustard holds the first position in terms of both total cultivation area and production and that was 2,52,227 ha and 2,46,000 tons, respectively (bbs, 2012). in bangladesh about 1.5 million ha of coastal land is affected by different degrees of salinity. most of the southern districts of the country are under saline zones which cover an area of 25-30% of the total cultivable land (srdi, 2012). salinity reduces growth and yield of non-halophyte by decreasing the availability of water to the roots due to the osmotic effect of external salt and by creating toxic effects of excessive salt accumulation within the plant. salinity occurs through natural or human induced activities that result in the accumulation of soluble salt in soil and the problem of soil salinity expected to boost in future with the progress of desertification process and greenhouse effect. mustard (brassica juncea) is a glycophytes, which often experiences saline stress as it is grown extensively in the arid and semi-arid regions of the world (singh et al., 2001). hence, it becomes necessary to examine the underlying processes involved in salt tolerance in mustard plants. while screening some cultivars of b. juncea, hayat et al. (2011) categorized cv. varuna as salt tolerant and cv. rohini as salt sensitive and attributed this differential salt tolerance to salt-induced changes in fresh and dry biomass. though soil salinity is the most dominant factors limiting crop production in the saline areas of bangladesh during dry season, salt tolerant mustard crop can bring substantial changes in the agricultural practices in that problem soils. taking this into consideration, the present study was undertaken to examine the salt-induced modulation in the dry matter accumulation and yield in salt-tolerant and salt sensitive mustard genotypes. mailto:mannanbsmrau@yahoo.com 66 zaman et al. materials and methods an experiment was conducted in earthen pots of 24 cm in diameter and 30 cm in height in net house under semi controlled environment (inside plastic house) and natural light in the department of agronomy, patuakhali science and technology university, patuakhali, bangladesh during rabi 2011-12. each pot was filled with mixture of 12 kg air-dried soil, compost (25% of the soil volume) and 0.35-0.38-0.22 g of urea, tsp and mop. ten uniform bold seeds of four mustard genotypes viz.bd 9080, bari sarisha16, bd 9109 and bd 9107 were sown at first week of october 2011. the soil used in experiment was clay loam in texture having ph 6.9, ece0.33 ds/m, esp 8.2 per cent, cec 16.69 cmolc kg-1 dry soil and organic carbon 0.55 per cent. after seedling establishment, five uniform and healthy plants were allowed to grow. intercultural operations, weeding and pest control measures were taken properly when necessary. at autotrophic stage, sufficient quantities of salt solution were applied in treated pot. salt solution was prepared artificially by dissolving calculated amount of commercially available nacl with tap water to make 50 and 100 mm nacl solution which electrical conductivity (ec) were equivalent to 5 and 10 ds/m, respectively. to avoid salt stress shock, the salt solution was applied with an increment of 25 mm in every alternate day till respective concentrations were attained. plants in control group were irrigated with tap water (normal). the salt solutions were applied till harvest. the experiment carried out in completely randomized design with four replications. the observations on shoot and total dry matter per plant, number of siliqua per plant, number of seeds per siliqua, 1000-seed weight and seed yield per plant were recorded. the data recorded for different parameters were statistically analyzed using mstat-c computer program and mean differences were adjusted by lsd technique (gomez and gomez, 1984). results and discussion shoot dry matter per plant shoot dry weight of all mustard genotypes was affected by both salinity levels significantly. reduction in shoot dry weight due to salinity was lower in genotype bd 9080, whereas that was higher in bd 9107. the shoot dry weight was reduced by 37% in genotype bd 9080 and by about 59% in bd 9107 at 100 mm nacl salinity (fig. 1). shoot dry matter reduction was more than 50% in other genotypes under higher salinity level. shoot dry matter was also significantly affected at 50 mm nacl salinity level. compared to other genotypes studied, genotype bd 9080 was less affected by 50 mm nacl salinity stress. in respect of shoot dry matter production under saline environment, genotype bd 9080 showed higher salt tolerance than the other genotypes. reduction in shoot dry weight due to salinity as compared to control was reported earlier by ghuge et al. (2011) in two brassica juncea cultivars and raziuddin et al. (2011) brassica napus (cultivar abasin) and brassica juncea (cultivar nifa-raya). it was reported that salt stress caused low photosynthesis (pn) which was associated with a low demand for photosynthate in the sink (sultana et al., 1999). the less reduction in photosynthesis of tolerant genotypes at high salt concentration than susceptible group might have contributed to maintain better growth through shoot dry matter production in the genotype bd 9080 than the bd 9107. 67 salt induced in dma and yield of mustard total dry matter per plant both 50 mm and 100 mm nacl salinity affected significantly the total dry matter production in all the mustard genotypes studied. total dry matter reduction due to salinity was lower at 50 mm salinity level than that at 100 mm nacl level. salinity induced differences in total dry matter production among the genotypes were caused by the differences in the reduction of root, leaf, and stem dry matter over their control (data not present). the minimum reduction in total dry matter was noticed in genotype bd 9080 (36%), whereas the maximum (59%) was in genotype bd 9107 (fig. 2). the dry matter reduction in bari sarisha16 and genotype bd 9109 was in between this minimum and maximum range. the total dry matter in bd 9080 was less affected even at high salinity level, which could be attributed to more efficient production of leaf, stem and root dry matter. thus, dry weight per plant was adversely affected by increasing levels of salinity. reduction in total dry matter accumulation under saline condition was also reported by neelam et al. (2010) and shamsul et al. (2011) in indian mustard (brassica juncea) and memon et al. (2010) in brassica campestris l. number of siliqua plant-1 number of siliquae reduced significantly with each increase in salinity level. the reduction was higher at 100 mm nacl salinity compared to that at 50 mm nacl. the reduction in siliqua per plant at 50 mm nacl ranged from 5% to 35%. however, at 100 mm nacl genotype bd 9107 produced only 42% siliqua of the control. the production of siliqua per plant at 100 mm nacl reduced to a great extent and ranged from 12% (in genotype bd 9080) to 58% (in genotype bd 9107) (table 1). negative effect of salinity on number of siliqua per plant of indian mustard [brassica juncea (l.) czern & coss] was also observed by kripa et al. (2011). number of seeds siliqua-1 salinity also reduced the average number of seeds per siliqua significantly in all the mustard genotypes studied (table 1). the number of seeds per siliqua was affected a little by 50 mm nacl salinity in most of the genotypes, except genotype bd 9107. under 100 mm nacl salt stress, the highest relative seed number per siliqua was produced by the genotype bd 9080 (74%), followed by bari sarisha 16 (63%) and bd 9109 (45%) and the lowest by genotype 68 zaman et al. bd 9107 (33%). these results corroborate to the findings of omae et al. (2005) and ahmad (2010). thousand seed weight (gm) 1000-seed weight showed significant reduction with increase in salinity level in all the mustard genotypes studied. at 50 mm nacl salinity level, 1000-seed weight ranged from 2.12 g to 3.02 g, whereas at 100 mm nacl that was from 1.77 g to 2.87 g (table 2). relative grain weight was the highest in genotype bd 9080 (86 %), followed by bari sarisha16 (76 %) and bd 9109 (72 %), and it was the lowest in genotype bd 9107 (51 %) at 100 mm nacl. a remarkable reduction in the size of seeds was observed at 100 mm nacl in all the genotypes. it might be attributed to disturbed absorption of moisture and nutrients, limited formation of photosynthates and their lesser translocation towards seeds resulting reduction in seed weight. table 1. number of siliqua per plant and number of seeds per siliqua of four mustard genotypes as affected by nacl salinity genotypes number of siliqua plant-1 number of seeds siliqua-1 nacl (mm) nacl (mm) 0 50 100 0 50 100 bd 9080 82.25 78.50 (95) 72.00 (88) 16.25 15.00 (92) 12.00 (74) bari sarisha16 185.50 167.25 (90) 151.50 (82) 10.00 8.00 (80) 6.25 (63) bd 9109 71.25 62.75 (88) 50.75 (71) 29.75 18.00 (61) 13.50 (45) bd 9107 82.50 54.25 (65) 34.75 (42) 21.25 13.25 (45) 7.00 (33) lsd (0.01) 6.84 4.31 cv (%) 3.88 15.61 values presented in parentheses indicate per cent values to the control. in genotype bd 9080, relative seed weight was higher with compared to other genotypes which indicated that this genotype was more capable to partition more dry matter into the seeds than that of other genotypes, especially at higher level of salinity. seed yield an inverse relationship was found between salinity levels and seed yield in mustard. seed yield was reduced by salinity in all the mustard genotypes studied and the decreasing rate was higher with the increasing level of salinity. seed yield of different genotypes ranged from 4.43 to 6.00 g plant-1 under normal condition and that from 2.96 to 5.61 and 2.49 to 5.24 g plant-1 under 50 mm and 100 mm nacl saline conditions, respectively (table 2). the highest relative seed yield plant-1 was found in genotype bd 9080 at both the salinity levels and the lowest was in genotype bd 9107. most of the yield contributing traits is less affected under 100 mm nacl stress in genotype bd 9080. so yield difference of 50 mm and 100 mm nacl is very near of this genotype. the highest relative number of siliqua plant-1 and individual seed weight in genotype bd 9080 mostly contributed to the highest relative seed yield of this genotype. 69 salt induced in dma and yield of mustard table 2. 1000-seed weight and seed yield plant-1 of four mustard genotypes as affected by nacl salinity genotypes 1000-seed weight (g) seed yield (g) plant-1 nacl (mm) nacl (mm) 0 50 100 0 50 100 bd 9080 3.33 3.02 (91) 2.87 (86) 6.00 5.61 (93) 5.24 (87) bari sarisha16 3.75 3.01 (80) 2.85 (76) 4.43 3.71 (83) 3.22 (72) bd 9109 3.65 2.70 (74) 2.63 (72) 5.38 4.22 (78) 3.26 (60) bd 9107 3.45 2.12 (61) 1.77 (51) 5.66 2.96 (52) 2.49 (43) lsd (0.01) 0.76 0.37 cv (%) 12.97 4.26 values presented in parentheses indicate per cent values to the control. this finding supported by kripa et al. (2011).the poor seed yield under saline environment was attributed to salt induced shrinkage and even complete damage of chloroplast, decrease in photosynthates in the phloem and water deficiency in the growing region (flowers et al, 1991). according to ashraf et al. (1999) the reduction in seed yield may also be due to decreasing assimilates production associated with decreased plant size and yield. the correlation matrix between the yield attributes of mustard subjected to salinity (table 3) showed that seed yield plant-1 was strongly associated with the shoot mass plant-1 (r = 0.829**), number of siliqua plant-1 (r = 0.904**) and number of seed siliqua-1 (r = 0.981**). there were a weak relation between yield and 1000-seed weight (0.538*). weight of 1000-seed (r = 0.344*), number of siliqua plant-1 (r =0.532*) and number of seed siliqua-1 (r = 0.349*) were positively related to shoot mass plant-1. correlation coefficient analysis showed that among those components number of siliqua plant-1 had the maximum direct contribution to yield and number of seed siliqua-1 and individual seed weight were the dominant contributors to seed yield. table 3. correlation coefficient (r) among the shoot mass and yield attributes of mustard subjected to salinity characters shoot mass plant-1 number of siliqua plant-1 number of seeds siliqua-1 1000seed weight (gm) yield plant1 shoot mass per plant 0.532 * 0.349 * 0.344 * 0.829 ** number of siliqua per plant 0.669 ** 0.524 ns 0.904 ** number of seeds per siliqua 0.304 ns 0.981 ** 1000-seed weight 0.538 * ** correlation is significant at the 0.01 level (2-tailed). * correlation is significant at the 0.05 level (2-tailed). ns non significant 70 zaman et al. references ahmad, b. 2010. effects of salinity on yield and component characters in canola (brassica napus l.) cultivars. not. sci. biol. 2 (1): 81-83. ashraf, m. y., r. a. waheed, a. bhatti, s. a. baig and z. aslam. 1999. salt tolerance potential in different brassica species: growth studies. p. 119-125. in: harndy, a., h. lieth, m. todorovic and m. moscheuko. (eds.) halophyte use in different climates ii.backhuy pubs. leiden, the netherlands. bbs (bangladesh bureau of statistics) 2012. agriculture wing, statistical pocket book of bangladesh, planning division, ministry of planning, government of bangladesh. fao (food and agricultural organization of the united nations) 2004. terrastat database. at: <http://www.fao.org/ag/agl/agll/terrastat/>. flowers, t. j., m. a. hajibagheri and a. r. yeo. 1991. ion accumulation in the cell walls of rice plants growing under saline conditions: evidence for the oertli hypothesis. plant cell environ. 14:319–325. gomez, a. a. and a. a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. pp. 20-215. hayat, s., b. a. mir, a. s. wani, s. a. hasan, m. irfan and a. ahmad. 2011. screening of salttolerant genotypes of brassica juncea based on photosynthetic attributes. j. plant interact. 6: 53-60. kripa, s., s. k. s. parihar, k. kuldeep,d. kant and k. arun. 2011. relative salt tolerance of indian mustard (brassica juncea) genotypes in relation to germination, growth and seed yield. j. oilseed brassica. 2(2): 76-82. neelam, s., g. dipti and k. navjyot. 2010. effect of induced salinity stress on growth and yield of indian mustard (brassica juncea). environ. ecol. 28 (2): 967-968. omae, h., a. kumar, y. egawa, k. kshiwaba and m. shono.2005. genotypic differences in plant water status and relationship with reproductive responses in snap bean (phaseolus vulgaris l.) during water stress. jpn. j. trop. agric. 49: 1-7. raziuddin, f., h. ghulam, m. akmal, s. s. shah, m. fida,. m. shafi, b. jehan and w. zhou. 2011. effects of cadmium and salinity on growth and photosynthesis arameters of brassica species. pak. j. bot. 43 (1): 333-340. shamsul, h., b. a. mir, a. s. wani, s. a. hasan, i. mohd, and a. aqil. 2011. screening of salttolerant genotypes of brassica juncea based on photosynthetic attributes j. plant interactions. 6 (1): 53-60. singh, h., b. p. singh and h. prasad. 2001. weed management in brassica species. indian j. agron. 46: 533-537. srdi. 2012. saline soils of bangladesh. soil resources and development institute. ministry of agriculture, farmgate, dhaka-1215. sultana, n. t., t. ikeda and r. itoh, 1999. effect of nacl salinity on photosynthesis and dry matter accumulation in developing rice grains. environ. and experiment. bot. 42: 211-220. bangladesh agron. j. 2017, 20 (1): 1-5 performance of mustard varieties in haor area of bangladesh z ahmed1 and m a kashem2 1farm productivity improvement project, sylhet agricultural university 2department of soil science, sylhet agricultural university, sylhet-3100 corresponding author, e-mail: duafroza@gmail.com key words: mustard, variety and haor areas abstract a varietal trial of mustard was conducted at noagaon village of dekhar haor areas of south sunamganj upazila of sunamganj district, during november 2015 to march 2016, to find out the suitable mustard variety/varieties. a total of five varieties viz. badc 1, sau sarisha-3, bari sarisha-11, bari sarisha-14 and bari sarisha-15 were tested in the farmer’s field. the experiment was carried out in a randomized complete block design with three replications. significant differences were found among the mustard varieties for number of branches plant-1, number of capsules plant-1, capsule length, 1000-seed weight and seed yield. the mustard var. bari sarisha-11 produced the highest number of branches plant-1, number of capsules plant-1, 1000-seed weight resulting the highest seed yield (1.64 t ha-1), followed by bari sarisha-15 (1.47 t ha-1). the seed yield of bari sarisha-11 and bari sarisha-15 was not differed significantly, but the growth duration of bari sarisha-15 was shorter than the others. introduction mustard (brassica sp.) is one of the most important oilseed crops throughout the world after soybean (fao, 2014). among the oilseed crops grown in bangladesh, mustard holds the first position in terms of area and production as of 2,94,737 ha and 1,94,000 tons, respectively (bbs 2013). mustard seeds contain 40-45% oil and 20-25% protein. mustard is not only a rich source of energy (about 9 kcal g-1), but also rich in fat soluble vitamins like a, d, e and k. the oil production is low compared to our demand. for this reason every year a large amount of oil and oil seeds are imported in our country. increasing production of mustard may be one of the way to minimize demand supply gap of edible oil in the country. production of mustard can be increased by bringing more lands of haor areas under mustard cultivation. haor with their unique hydro-ecological characteristics are large bowl shaped floodplain depressions that remains flooded from late may to october. in haor areas of north-eastern districts of our country mostly one crop i.e. boro rice is widely cultivated. due to flash flood and existence of water for long time it is almost difficult to cultivate more than one crop in that area. after receding of flood water from the comparatively high land of haor areas, there is a greater possibility of growing short duration mustard in this adverse ecosystem and a portion of monocropped land can be brought under double-cropped area. hence, the experiment was done to find out the suitable mustard variety/varieties for increasing productivity in the haor areas of sunamganj district. 2 z ahmed and m a kashem materials and methods the research work was conducted in the haor areas of south sunamganj upazila of sunamganj district, during the period of november 2015 to march 2016. the soil of the experimental area was silt-loam in texture. the experimental fields were medium high land with well drained condition. five mustard varieties viz. badc 1, sau sarisha-3, bari sarisha-11, bari sarisha-14 and bari sarisha-15 were used as test crops. the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 6.5 m x 2.5 m. fertilizers were applied at the rate of 115-34-43-27 kg ha-1 of npks in the form of urea, triple super phosphate, muriate of potash and gypsum, respectively. one half of n and full quantity of other fertilizers were applied as basal during the final land preparation. the remaining n was top dressed at 30 days after seed sowing (das). seeds of different mustard varieties were sown on 15 november 2015 as broadcast method at the rate of 7 kg seeds ha-1. different types of weeds were controlled manually and removed from the field on 7 to 10 december 2015. the crop was irrigated at 35 das. malathion 57 ec @ 2 ml/l water was sprayed to control aphids at the time of flowering. the crop was harvested plot wise when 90% capsules were matured. the varieties badc 1, sau sarisha-3, bari sarisha-14 and bari sarisha-15 were harvested on 24, 14, 5 and 6 february 2016, respectively, while bari sarisha-11 was harvested on 9 march 2016. data on plant height, branches plant-1, capsules plant-1, capsule length, seeds capsule-1, weight of 1000seeds, seed yield, stover yield and biological yield were recorded and harvest index was calculated. data were analyzed by using mstat-c computer program and means were compared by duncan’s multiple range test (dmrt) technique (gomez and gomez, 1984). results and discussion year round weather pattern of noagaon village at noagaon of south sunamganj upazila, august was found as the warmest month of the year. the average temperature in august was 28.20 c. the lowest average temperature in the year occured in january when it was around 18.20 c. the driest month of noagaon was in december with 6 mm and 703 mm of rain in june. table 1. temperature, rainfall and flooding depth pattern around the year at noagaon name of the month temperature 0c rainfall (mm) flooding depth (m) minimum maximum average january 11.5 25.0 18.2 13 0 february 13.6 27.4 20.5 23 0 march 17.8 31.1 24.4 93 0 april 21.5 32.1 26.8 253 2.5 may 23.0 31.3 27.1 485 4.5 june 24.6 30.9 27.7 703 6.5 july 25.2 31.1 28.1 634 7.0 august 25.2 31.3 28.2 521 6.5 september 25.0 31.4 28.2 394 5.0 october 22.6 30.6 26.6 201 2.0 november 17.8 28.6 23.2 27 0.5 december 13.2 25.9 19.5 6 0 3 performance of mustard varieties in haor area of bangladesh the highest 7.0 m flood water remained in the month of july whereas from november to march no standing water prevailed in the basin like haor areas when different crops can be cultivated. effect of variety on yield components of mustard all the varieties were significantly differed in respect of plant height and other yield contributing characters except branches plant-1. the maximum plant height was observed in bari sarisha-11 (126.33 cm) followed by badc 1 (101.06 cm). but plant height was obtained from badc 1, sau sarisha-3 and bari sarisha-15 was statistically identical which was 101.06 cm, 99.65 cm and 95.23 cm, respectively. the shortest plant (83.84 cm) was found in bari sarisha-14 (table 2). these results are supported by islam et. al. (2011). bari sarisha-11 produced the maximum number of branches (5.0) plant-1 followed by bari sarisha-15 (4.93). but all the varieties did not differ significantly in case of number of branches plant-1 (table 2). bari sarisha-11 produced significantly the highest number of capsules plant-1 (147.53). badc 1 and bari sarisha-15 produced the statistically similar number of capsules plant-1 which is 98.96 and 97.96, respectively. the lowest number of capsules (80.16) plant-1 was produced by sau sarisha-3 which is statistically similar to bari sarisha-14 (table 2). number of capsules plant-1 is a genetically control trait but it can be changed by management manipulation like number of plants per unit area along with fertilizer application rate. bari sarisha-11 produced profuse branch which bears more capsules than other varieties. this result is in agreement with the findings of islam et al. (2013). bari sarisha-15 produced the longest capsule (5.06 cm) followed by bari sarisha-14 (4.96 cm) but both are statistically similar. capsule length found from sau sarisha-3, bari sarisha-11 and badc 1 were statistically identical which were 4.65 cm, 4.54 cm and 4.45 cm, respectively and hence the shortest value for capsule length was from badc 1 (table 2). the trial varieties produced significantly different seeds capsule-1 and the maximum number of seeds (22.93) capsule-1 was produced by bari sarisha-14 which is statistically similar to bari sarisha-15 (21.44). table 2. effect of variety on plant height and different yield components of mustard variety plant height (cm) branches plant-1 (no.) capsules plant-1 (no.) capsule length (cm) seeds capsule-1 (no.) 1000seed wt (g) badc 1 101.06 b 4.73 a 98.96 b 4.45 b 9.71 d 2.16 b sau sarisha-3 95.23 b 4.83 a 80.16 c 4.65 ab 17.32 b 2.50 ab bari sarisha-11 126.33 a 5.00 a 147.53 a 4.54 b 12.89 c 3.00 a bari sarisha-14 83.84 c 4.76 a 82.00 c 4.96 a 22.93 a 2.16 b bari sarisha-15 99.65 b 4.93 a 97.96 b 5.06 a 21.44 a 2.50 ab lsd (0.05) 8.10 ns 9.51 0.40 1.86 0.69 cv(%) 2.92 4.86 3.43 4.52 4.04 18.69 in a column, figures having common letters (s) do not differ significantly the number of seeds capsule-1 produced by sau sarisha-3, bari sarisha-11 and badc 1 was 17.32, 12.89 and 9.71, respectively are statistically different to the highest value (table 2). in terms of 1000-seed weight trial varieties showed significant difference and the highest 1000seed weight (3.0 g) was found in bari sarisha-11. 1000-seed weight in case of both sau 4 z ahmed and m a kashem sarisha-3 and bari sarisha-15 was 2.5 g. the lowest value (2.16 g) for this parameter was found in badc 1 and bari sarisha-14 varieties (table 2). effect of variety on yield of mustard the seeds of the tried varieties were sown at the same date but the plants were harvested in different dates. bari sarisha-14 was found to be the shortest in crop duration (82 days) followed by bari sarisha-15 (83 days). the duration of sau sarisha-3, badc 1 and bari sarisha-11 were 91, 101 and 115 days, respectively (table 3). the maximum seed yield was found from bari sarisha-11 (1.64 t ha-1) followed by bari sarisha-15 (1.47 t ha-1) but the difference was statistically insignificant. the seed yield found from sau sarisha-3 and badc 1 was statistically similar which were 1.22 and 1.19 t ha-1, respectively. the lowest seed yield (1.01 t ha-1) was obtained from the shortest duration variety bari sarisha-14 (table 3). bari sarisha-11 produced the highest number of branches plant-1, number of capsules plant-1, 1000-seed weight resulted the highest seed yield. this difference in seed yield was probably due to the difference in genetic potential of the varieties, which might have contributed toward the final yield. bari sarisha-11 produced the maximum stover weight (3.85 t ha-1) than that of other varieties (table 3) but all of them did not differ significantly. the maximum biological yield (5.49 t ha-1) was found from bari sarisha-11 followed by bari sarisha-15 (4.93 t ha-1) but both are statistically similar. biological yield found from sau sarisha-3 and badc 1 were 4.41 and 4.3 t ha-1, respectively which are statistically identical. the lowest biological yield (3.41 t ha-1) was found from bari sarisha-14 followed bt badc-1 (table 3). it might be due to higher plant height and long crop duration possessed by bari sarisha-11. bari sarisha-11 exhibited the highest value (29.96%) of harvest index followed by bari sarisha-15 (29.84%) and barisarisha-14 (29.75%). these results of varietal difference were in agreement with some works of minir and mcneilly (1986). table 3. crop duration and yield of different mustard varieties variety crop duration (days) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) badc 1 101 1.19 b 3.11 a 4.3 b 27.76 b sau sarisha-3 91 1.22 b 3.19 a 4.41 b 27.67 b bari sarisha-11 115 1.64 a 3.85 a 5.49 a 29.96 a bari sarisha-14 82 1.01 c 2.4 a 3.41 c 29.75 a bari sarisha-15 83 1.47 a 3.46 a 4.93 ab 29.84 a lsd (0.05) 0.17 ns 0.66 1.17 cv (%) 5.05 5.73 5.38 1.48 in a column, figures having common letters (s) do not differ significantly conclusion the result of this trial revealed that the maximum seed yield (1.64 t ha-1) was produced by the mustard var. bari sarisha-11, which was statistically similar to bari sarisha-15 (1.47 t ha-1). 5 performance of mustard varieties in haor area of bangladesh bari sarisha-15 is also a short duration variety compared to bari sarisha-11 and the short duration is an important factor for selecting variety/varieties for haor areas. references bbs (bangladesh bureau of statistics) 2013. agriculture wing, statistical pocket book of bangladesh, planning division, ministry of planning, government of bangladesh. fao (food and agriculture organization of the united nations) 2014. terrastat database. at:http://www.fao.org/agl//agll/terrastat/. gomez, a. a. and a. a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. pp. 20-215. islam, m. n., m. s. rahman, f. ahmed, m. s. alom and m. akhteruzzaman. 2013. performance of different hyv mustard varieties with sugarcane (saccharum officinarum) as intercrop in framers’ fields. bangladesh j. agril. res. 38(2): 211-217. islam, m. n., f. ahmed, m. s. a. khan and w. sultana. 2011. varietal trial of hyv mustard at newly developed charland. in charland research 2007-2010, agronomy division, bangladesh agricultural research institute, joydebpur, gazipur. pp. 01-04. minir, m. and t. mcneilly. 1986. variation in yield and yield components in six varieties of spring oilseed rape. pakistan j. agric. res. 7: 21-27. http://www.fao.org/agl/agll/terrastat/ microsoft word final.doc � �������� �� ������������� �� ������������� �� ������������� �� ��������� ���� �������������������������������� �!"#!�� $%%$�&�'%�()*��(+�),$%%$�&�'%�()*��(+�),$%%$�&�'%�()*��(+�),$%%$�&�'%�()*��(+�),�(&�$-&.��&$+�)/.',01($'2����0+�'(���(&�$-&.��&$+�)/.',01($'2����0+�'(���(&�$-&.��&$+�)/.',01($'2����0+�'(���(&�$-&.��&$+�)/.',01($'2����0+�'(�� /0$,+�'%�/0$,+�'%�/0$,+�'%�/0$,+�'%���������������������.0�$�.0�$�.0�$�.0�$����� ���� ������������3��3�� 3��3�� 3��3�� 3��3�� ������3���3���3���3�����4�����4�����4�����4�����������0���0���0���0�����%�����5�� �6%�����5�� �6%�����5�� �6%�����5�� �67777��3���3���3���3�����������������4��3�����4��3�����4��3�����4��3�����������������3�����3�����3�����3�����(��4�8 �(��4�8 �(��4�8 �(��4�8 ��������� ��������� �� �� �������� �� ����������������������������������� ���� �������� ��� ����� �������������� � �������� ���� �! �"�����������#����$%���� � �&���'� (������� &� ��������)��������*$%+�����'���� � .� �� �'�69�� ����:��,��� ��� ���� ���;��� <�����<�������������&��� 6������<� �� �� ��� ��5� �������������� ����� ���������� �� �����5���� � ������� ��=��������� ��;������ ���*���������>����� �5����� ���� �:������6��������?�����?�����?�7������"�??�����#������;� ��:��6��0..0���������+��;�;�� � �����<� ���5� ���������� ��������� �� <������9��� � �� ���� ���� � ;��� ���� ��� �2�1�� ��� ��� ����� ��� 5���� ��� �� ����������� ����<<� ��� 6��3�����6����������!@!����2�1���8 ��������6����#�� ���;;�� ����������� �� ��� 5����� ���:������� 5������� � �<� �� �;;�� ������ �<� )2� ��8 ����� �5�� ��� ������ �;���� �;;�� ������� ��� �������������<� ����(�������� a����:����������;6�������� ��� �������� �����������8 �������������<�� ������������� � b ������ �<�<�����5����b ����������������� ���������b6� ��� ����;��� ������a����:������� ���b���;;����� ������������� �<� ��������;� �� ����������;�; ��������<�b���<� ���� � ��b����������;�� ����;����� ����� ���5���� ).4� ��� ������ �� ��� ��� �� ��8 ��� ��� ����� 5�� �� ��� �c��� ���� <�� � <� ���� ���� ������ ��� ���� ������������ ��� ��=�� ��� :����������;6�������� �� � ���� 0�� ������d������� �� ���b�� ���� ��� �� ��� 5������ ��9�� <������ ��� 5���� ��� ��� ������ ������ ��;��� 0�� ����� �� ������� ���� � b��� �<� � ��������� ��;��������������������� ���� ��������������5������� ��� � ��b����� ��:��6��3�� � �����������7��<� ���������� ��������6����������<� ����6��� �������5����).4�5������ ��;�������5���� "�d��..0��� � ������������<�<������9���<����� ���&����<���������;��������� �6�5��� ������=��� �������:�� ���� �����<<� � 6��<�).4���� ������������ ����� ;������� ��������� � ������������<� <������9���� �����������b������ ������������ ��;�� ��<������c;��� ����5��� ��� ����������������� 6������� ��<������<�����#�#����������� �� ���� 2��:�����6�� +��=�#����� � ����� ���� ;������ <�� � (�:� b���� ����� ��� 3�6�� ���7�� &��� :�����6� ���� ��� ����� �c;��� ���� 5��� �..0� �����!�� &��� �c;��� ���� 5��� ����� � �� ��� �� .���� �9��� �� ;�������� =�+������ �.��+��5���� ������ ��;�� ��������&��������� �5��:�� ����� �����:�9���&��e� �������� ����()*�<������9�����&��e�(�����������<������9����&7�e�(��;���;��� ��<������9����&��e�(�� ;������ �<������9����&"�e�"�d��� � ������������<����� ���� ��������"�d�).4��<� ���:��������� &?�e�"�d��� � ������������<�;���;��� ��<������9�������"�d�).4��<� ���:���������&��e�"�d� �� � ������������<�;������ �<������9�������"�d�).4��<� ���:���������&@�e�"�d��� � ������ ����� �<� ()*� <������9��� ���� "�d� ).4� �<� ��� :�������� ;��;����� b6� ���� �� ).4� ��� ��� ������ �<� 5������� &!� e� ���d� �� � ������ ����� �<� ()*� <������9���� &��� e� ���d� ).4� �<� ��� :�������� ;��;�����b6����� ��).4�������� ���<�5�������&���e������� ����� ;������� ����;������������&���e� ���� �� ���� � ;��� ���� ���� ;��� �� ������ ���� "�d� ).4� �<� ��� :��������� .� � ������ ����� �<� <������9���<���b������ �����2�����&�)��3�)��16;� �����f�� �� �;�����g������!�������?������ ���=����#�������;� ��:��6��2����� ;������� ����5�����;;�����g��?�=��(���#�������<������9����5���� �;;������ �����<����������;��;���������c �;�� �����5�� ��5����;;���������������8 ����;�����������7�� ����"��+�&��%�������;;�� �������<�).4�������������������� ����������� �����;;������2����� ;��� ���� ����5����;�� ���������� �������<�<� ���������<��5����h� ������5��������+�&��&����6���6����� ����������5���� ;����������������;��������������<��������+� � b�������������������:�������5��� ��������3�6��������7� �� ���6� <�� ��� ��;��������� ���� ���� ���������5��������69����������� !?� 3�� �������� ���� ��<<���� ��� � ���� ���� ����� ����� 5���� � ;����� b6� + � ��i�� 3 ���;��� .����� &���� �1� �9�����1� �9���!@���� �����<� ���� :��������� 5��� �b���:��� ��� ��� �� �<� �<<� ��:�� �������� ����#��� ���#�<<� ��:�� �������� ����#��� ;��� �����������<������������� �<��������������������#������5�������&�b�������0��5����b���:������������ ����������@�7"��� b����<��<<� ��:��������������#��5����b���:���<�� ���������� ����&���5����������� ���5��� �� ����� ���� �<� ������� j;����� b �� � 5��� �������� ���6� �� ����� 5���� ������ ����� ����� �c �;�� &���&��� �c� �;��� ����������5���;��� ���<�� �&�������&!�;��� ���������5���������7� �� �� &��� �������� ��������� � b��� �<� <������ ������� ;��� ��j� ;��� ��� 5��� �� ������ <�� � &��� 5����� ��������&���;��� �������������������!���� b����<� �<�������������;��� ���j�;��� ����&�����5��� ��� ��<������ ������ �b���:��� ��� ����#� ������ 5������� &��� �������� ������ 6����� � �?�?�� �� ��#��� � 5��� �b���:���5����� ����� ;������� ������������;���������������"�d�).4��<� ���:���������b6�!@�"�d� ��������� ��������&�������b6�7"��7d�<�� ��������d��� � ������������<�()*�<������9�����&!���� �;;�� ������ �<� "�d� �� � ������ ����� �<� ()*� <������9��� ���� "�d� ).4� �<� ��� :�������� �&@�� �� �������������6������<��� ��b6����7�d������ ��������&�����*�b��������������!���3�� ������������@�� �����..0����������;������������;;�� �������<�2�1�;��� ������������ ��������6����������;������� ����� � &��� �������� ����5� 6����� ���!�� �� ��#��� 5��� ;��� ��� b6� ���� ����� ���� &��� 5�� �� 5��� �������� ���6��� �����5����&��5���������������� �����5������ ������������5�6������ ���� &�b������$<<� ���<���<<������<������9�������������).4����6����� � ;��������<�b������ ��:�����..0� �����!� &���� ����� $<<� ��:�� �������� ����#�� ������ (��� �<<� ��:�� ������������#�� ������ )��� ��� ������� � �� %������������� ;��� ��#�� 2�<������ ������� ;��� ��#�� ����# ������ 5������ ���� 1����� 6����� ����#��� ����5� 6����� ����#��� &������������ �7��7�b� "�?���� �������b� ��"�?���� ���!���� ������ �� 7�7"��� �����b� &�� �7�77�b� ��@���b� ���!���b� ����?��b#�� ���"��b#�� ���@��b#�� 7�@���� ?�@@�b� &7� ����7�b� "�?���� �������b� ��?���� �� ���@��b#�� ���@��b#�� 7��"��� �����b� &�� �7�?��b� "�����b� ����?��b� ����"��b#�� ����"� �� �������b� 7�@���� ���!�b� &"� ������b� ������b� ���?��b� ����?��b#�� ����"�b#�� �������b� 7��@��� �����b� &?� �7�@��b� ������b� ���?!��b� ��@����b � ���?��b� ����7��� ��"���� �����b� &�� ���77�b� ������b� �7��"��� ����?��b#�� ������b#�� ����?�b#�� ��?���� ���"�b� &@� ���@"�b� ��"7��b� ���"!�b� ��@�@��b� ���!?�b#�� �7�����# � ������� ?�?��b� &!� �7����b� ��?���b� ����7�b� ��@����b � ���7@�b� ���!��b#�� ��@�� �� ?��!�b� &��� �7�?"�b� "�"7��� ���?��b� ��!�7��b� ����@�b � ���@7�b#�� ?����b� ?�@7�b� &��� �"��7�b� "�7���� �������b� ��@����b � ������ �� ����@��� "�7!� � ���"�b� &��� �@�7"��� 7�����b� ���!���b� ��������� !�@!���� �7�"���#�� ?�?���� ��!���� �>��d�� �7���� ���!7� ?�"�� ���@� "��@� ��?@� ?�!7� ����� &��e�������������()*�<������9�����&��e�(�����������<������9����&7�e�(��;���;��� ��<������9����&��e�(��;������ �<������9���� &"� e� "�d� �� � ������ ����� �<� ���� ���� ���� ���� "�d� ).4� �<� ��� :��������� &?� e� "�d� �� � ������ ����� �<� ;���;��� ��<������9�������"�d�).4��<� ���:���������&��e�"�d��� � ������������<�;������ �<������9�������"�d�).4� �<� ���:���������&@�e�"�d��� � ������������<�()*�<������9�������"�d�).4��<� ���:���������&!�e����d��� � ������ ������<�()*�<������9����&���e����d�).4��<� ���:���������&���e������� ����� ;������� ����;������������&���e������� ���� � ;������� ����;���������������"�d�).4��<� ���:������������ � %�� ������b�:����� ���� ��� ���b�� �� � ����������;;�� �������<������� ����� ;������� ����;����� ����������"�d�).4��<� ���:�������� �����b ���������������������6��������������� ������� ���� ���� ���� !�� $<<� ���<�()*�����;�����$c��� ����)6�������� ��� ������/������<������.� �� .�<���� ��.�<���� ��.�<���� ��.�<���� ������ ���� �..0� ������������.� ��.����� �� 0����� �������������� ���.�;���� <����!!!#�����������������.� �� .����� ��0����� ������6��b; ���1�9�; ���;��7@��� 1� �9�� *�� ��� ���� ��� ��� 1� �9�� �!@��� + � ��k�� 3 ���;��� .����� &����� �������� ��� )�� �� ���� <��� ���� �� ���� .����� ��� ���� $����� �� a���6� 0����#� ��� �� ) b�� ������� ����� a���6� ���� ������ (�5�/��=��;;����#��"�� 0..0� �0������������� .� �� .����� �� 0����� ����� ������ a����� .� �� �������� ��� l���; jj�� ������� �������� @�@�j5���j����6;������� m� *�b����3��4���3�����.�����=����������*��3�����4�����5�� �6�����!��$<<� ���<� ����� ;������� ����� ;������� ��������;� ���6� �� ����������6������<������;������ ����� ��:������������������������� �������2��:������ ��"!#�?7�� 3�� �����3���3��4����������3�����2���������@��1��5�������6������<��5��&��� ����� ��:������������ �<<� ����b6����������� b�������#������ ����� ;������ ������������ ���� ���� �����������n��� � "�#"@��� 3�� �����3���3��3���=��3�����4��3�������3��4��4�8 ������f���=���������7�� 0�<� �� ���<�;����� �c��� ����;6�������� ��� �����������;�������� ����� ������$c;������� ������� �7�#7��� 3�����6�� ��� *��� ��� )�� ���=��:����� ���� ��� ������ ���� �� �!@!�� (�������� b���� ��� �� ����� ��� �� �� ������"�(#��b����� ����� ;������� ������������ ��� �����7��� ���!#����� � � � � microsoft word final.doc � �������� ��� �������������������������� ��� �! �"#����#$%��� �! �"#����#$%��� �! �"#����#$%��� �! �"#����#$%�! �""&'(�"�))$ �""&'(�"�))$ �""&'(�"�))$ �""&'(�"�))$ '�#)�%&$#��� �&'! $�#&'(� '�#)�%&$#��� �&'! $�#&'(� '�#)�%&$#��� �&'! $�#&'(� '�#)�%&$#��� �&'! $�#&'(� ! �""&'(�&')$'#&)*��'%�" �%�!)&+&)*�&'� ��#,�,&� $(&�'�! �""&'(�&')$'#&)*��'%�" �%�!)&+&)*�&'� ��#,�,&� $(&�'�! �""&'(�&')$'#&)*��'%�" �%�!)&+&)*�&'� ��#,�,&� $(&�'�! �""&'(�&')$'#&)*��'%�" �%�!)&+&)*�&'� ��#,�,&� $(&�'����� �������� �����'(-�%$#,�����'(-�%$#,�����'(-�%$#,�����'(-�%$#,���� ���� &��,� �.�&��,� �.�&��,� �.�&��,� �.��������/�� ��&��/��������/�� ��&��/��������/�� ��&��/��������/�� ��&��/�����������/�����& ��0��/�����& ��0��/�����& ��0��/�����& ��01111��/������2.2��/������2.2��/������2.2��/������2.2���������#��/��/�� ��3 �������#��/��/�� ��3 �������#��/��/�� ��3 �������#��/��/�� ��3 ��������������������40����������40����������40����������40�������� �#��.� �#5.��6.7.5��77.5� �1�#5.��6.7.5��77.5� �� ��.�����8 ��6� � �� 5 �!��6 ����� &�� �9 � .� �%. �56� �(��� �����! .�7�#5.��6.7.5��77.5� ���" .�5.:���#5.��6.7.5��77.5� ���" .�5.:���#5.��6.7.5��77.5� �� �������� ��� .54�64 ��� � �� 5 �&� 6.646�����;��<:4 ��(�2.:4 � !� � :���.����46 � ��.�.� = 5>�0�.��5�0� 3�;�=� � �3�;�=� � �3�;�=� � �3�;�=� � �������4 �5 �: ��5 �::.���.�6�� .6;��: ��456.?.6;�� .5���@4.?����6�;.�������� ���� �< 6 �56�< 6 �56�< 6 �56�< 6 �56���� ���� �� 7.���� 6 .��� =� � 5���456��� �6� 6 �� ��.����� 8 ��6� � �� 5 � !��6 �� �7� �������� � �� .54�64 ��� � �� 5 � &� 6.646�� ��� &��� �9 � .� 6�� 64�;� 6 �� 5�0:� �6.?�� �� ���0.5� :� 7� 0��5�������5���0.5� �64 ���7�7�4 �5 �: �<� ���5 �::.���:�66� � ��) ��5 �::.��� :�66� � �=� �� � � 7����= ��!"�a�) �� :���6����0��� .5�� �5?���.��� �����b/4 6� �� �5?�� �� &�#� . ����b�� �� .5���5?��� &�� ���c��b�) �� :���6����4 � .5���5?��"� .9��d�!"�a� )���0��� .5�b"�6�6�� �5?��%.�0��6�b�� �� .5�b)��4 � .5�d�!"1a)���0��� .5�b/4 6� �� �5?���� &�#� . ����b/4��<���� �5?���� &�/4������b)���4 � .5������!"��a�)���0��� .5�b�����=b�� �� .5�b�����=� �!��6 ����� ) �� � 4�6 � �=��� 6 �6� 7�4 � 5 �: � 5�4��� <�� � �=�� 455� 74��;������76� ����6 � �.���� �@4��5��.��6 ��7.����=.6 �6 ���5 �: �:�66� � ��� ) �� .� � 6� .5�� �@4.?����6� ;.���� � $*�� ������ 6� ���� =� � �<6�.���� 7 �0� 6 �� 5 �::.��� :�66� �� !"�� �)�� �0��� .5�b"�6�6�b�� �� .5�b)��4 � .5��� ���� .6� =� � 7����=��� <;� !"�� ��c��e�� ���� !"1� �����1�� �4 .��� ���� ;�� � 5 �: � 5;5���� ) �� .� � 6� � � � 0� �.�� )f�� ��ccc�� ���� =� � �� �� �<6�.���� 7 �0� !"�� � 7����=��� <;� !"1� �)f�� �111��� ������ ) �� .� � 6�/�! ��������=� � �=�?� ���<6�.����7 �0�6 ��5 �::.���:�66� ��!"1��)���0��b /4 6� �b�/4��<���b)���4 ������ �������?� ����;.����:� 7� 0��5����5���0.5�<���7.6����� 5�.0�6.5� .64�6.����7� �9 � .� ��.��� .6�0�;�<��5��5�4����6 �6�!"1�=� � 6 ��<� 6�:�66� �� 6 ����6 � �� ���� &�6 ��456.��&�6 ��456.��&�6 ��456.��&�6 ��456.������ ���� �������� �. ������ ��;�:�:4��6�������c�:� � @��f0���5�4�6 ;�=.6 ����� ����7����������� @�f0� �����:�:4��6.�����7��<�46���e�0.��.���=.6 ����.�5 �� .��� �6���7���1�g�:� �;�� ����#����������6� : � ��6�6�6���54�6.?�<��������. �c���0.��.��� �56� ��= .5 �. ���5 �� .����6�6 �� �6���7��<�46��g�:� � ;�� ��) � ��. �?� ;��.66��� 5�:��7� �.�5 �� .���54�6.?�6��������6 �4� �6 � ��. �����0:��� 5�:��7� � .�5 �� .���5 �::.���.�6�� .6;�7 �0�6 ��: � ��6��e�g�6�����g��<;�.�5� :� �6.��� � 6��4 �6.��� 5 �: �� �.f�� 04 6� ��� :�6�6��� 04��<���� ���� �4 � .5�� .�� 6 �� .5�� <� ��� 5 �::.��� :�66� � �� #4 6�.��<��� 5 �:� : ��456.��� .�� �������� � 6 �4� � .0: �?�0��6� �7� 5 �::.��� :�66� �� .�� .5�� <� ��� 5 �::.��� ; 6�0� . � ��� ���� � � .�5 �� .���;� .0:� 6��6� .�� ��6.����� . 4� � 45 � � � 7���� �54 .6;��:�?� 6;�����?.�6.�������5 ��6.����7�9�<��::� 64�.6;���2.2����� � 0������������) ��0�.�� 5 �������� �7� 6 �� ��=� 0.�����.40� . � 6�� .�5 �� �� :� � 4�.6� ;.���� <;� �6� ��� 6� ��g� 6 �4� � 0��.:4��6.���6 ���.0.6�������� � �4 5���&��6 . � ��� ���6 ��5 ������� �7� �6 ���� ���0. 6 �� ��6�� 4��� 6���� 5 �:� : ��456.��� : �<��0 � ���� : �5� � � 6�� ��?���:� 6 �� <� 6� =�; � �7� : ��456.��� 6�5 �����.� �7� �6 ��0�����0��6��7�: �<��0 ����� 4 6�.��<���: ��456.����&��5� ���7�: ��456.��� �� ���0;�� 6� ��6.��� .� � ;.���� 6 �4� � .� � 5 �::.��� .�6�� .6;� ���� : ��456.?.6;� . � 6 �� 0� 6� ���.5��� =�;� 6�� �. �� 6 �� 6�6��� : ��456.���� ,�=�?� �� .�� � �� � 6�� : ��45�� 0� �� 7���� =.6 .�� �� �.0.6���� ����6=��0� 6�.0:� 6��6��:6.�� �6��<�����:6���� ��.��6��.�5 �� ��6 ��5 �::.���.�6�� .6;� ��� ,� �.���6����� <;�: ��45.���6 ���� ��0� ��5 �: ��?� �6 �� �0��:.�5���7������.����;�� ������..��6��.�5 �� ��6 �� : ��456.����77.5.��5;��7�6 ��.��.?.�4���5 �:�<;�4 .����:6.040�0�����0��6�: �56.5� ��� �.� ��� � ����:4� � � � �� 6 �� .0:� 6��6� � �4:� �7� 5 �: �= .5 � � ��0� 6�;� � �=�� .�� �<.� �=.�6� �� �� ���.���������� ��) ��� �� ��7��.� ��� �����:4� � �.�� �<.� �� ���� ����5 �� .���<�5�4 ���7� .�5 �� .��� 54�6.?�6.��� �7� . .��6��� <� �� .5�� �8� �<� �6� ����� ������� �5��6�;�� =.6 � 6 �� ��?���:0��6��7� � 6��4 �6.��� .5���5 �: ��.f��04 6� ���:�6�6������:4� � �5���<���55�00���6��� .�� 7�4 � 5 �: � <� ��� 5 �::.��� :�66� �� .�� �� �0�� :.�5�� �7� ����� .�� �� ;�� �� �:� ����04 6� �� : ��456.���5���<��.�5 �� ���<;������g����;� �:��5.���6 ��.6.�����?� .�6;�<;� .� �;.���.��� � 6� �4 �6.��� ��� �� �.f���� &� #� . ����� ������ &� #� . ����� .�� 6 �� �h. 6.��� .5�� <� ��� 5 �::.��� ; 6�0��$�.� ��6�������ec����"4� � �� ��.� � ��6�;�.0:� 6��6�� �.�����40��5 �: �.���������� �7� � 6 �. �.0:� 6��5��� ��7�����7��������.�� �.��.0: �?�0��6�: �5� ���/�������6�������������) �;�� �� ���� ���;�� �=��=.6 �46�� ��.66���7� 6.�.2� � .�5��6 �;�5���0��6���0�9� �:� 6.����7�6 �. ��.6 ����� �@4. �0��6�<;� ;0<.�6.5�7.h�6.����7��60� : � .5��.6 �����.��6 �� �.���& ��0���ee����'�?� 6 ��� �� :4� � � 4::�;��� 4< 6��6.����0�4�6��7��.6 �����6��6 �� 455���.����������40��5 �: �� �=��.�� .5�� <� ��� 5 �::.��� ; 6�0� � �5 .�� ���� �<� 6 �� �e��d�� ��=�6� �6� ����� �ec�d�34 62� �6� ����� �ec�d� # � 0������" � �����eee���� ����4<6���;�� :�6��6.��� ���:6.��� �7� 04 6� ��� 04��<���� ���� :�6�6�� .�� )�� �0��������=��� �� �����=� 5 �::.��� ; 6�0� =�4��� .�5 �� �� 5 �:� : ��456.?.6;�� ���� �6�� �0:��;0��6� ���� < .��� ���.6.����� .�5�0�� 7� � 6 �� 4 ��� :�� � <;� 46.�.2.��� 7����=� ���� 4��� �4 ��� ���� � �7� 6 �� 5�4�6 ;�� ,�=�?� �� 6 �� <���7.6� �7� .�5� :� �6.��� �7� �h6 �� 5 �: � .�� 6 �� .5�� <� ��� 5 �::.��� :�66� �� =.��� �� ���;���:��� ����6 �� ���56.����7� 4.6�<���5 �:�?� .�6.� ��������:6.����7��:: �: .�6���� ���0.5� : �56.5� ��) ��: � ��6��h:� .0��6�=� �6 � �7� ���4��� 6�f���6�� 64�;�6 ���5���0.5�7�� .<.�.6;��7� � �=.���7�4 �5 �: �.����;�� �.����:.�5���7������<;�.�5� :� �6.���04 6� ���:�6�6���04��<�������� �4 � .5��.��6 ���h. 6.����6=��� �6 ���5 �: �<� ����:�66� ���� ���� /�6� .�� �����/�6 �� /�6� .�� �����/�6 �� /�6� .�� �����/�6 �� /�6� .�� �����/�6 �� ���� ���� ) �� 7.���� �h:� .0��6� =� � 5���456��� �6� 6 �� ��.����� 8 ��6� � �� 5 � !��6 �� �8 !�� �7�� �������� � �� .54�64 ��� � �� 5 � &� 6.646�� ��� &��� �9 � .� ��$i� ���� �4 .��� ��������1� ��4�;� �����6 �4� ��4������1���#�.������; . � �:� 6��7�6 ��7.����. �: � ��6���.��)�<��������4 �5 �::.��� :�66� � �=� ��� �7����= �� � !"��a�)���0���b�/4 6� ��b��� ��b�)���4 � !"��a�)���0���b�"�6�6��b��� ��b)���4 � !"1�a�)���0���b�/4 6� ��b�/4��<����b)���4 � !"��a�)���0���b������=�b��� ��b������=��5��6 ���� � )�<������&�.6.��� �.��: �:� 6.� ��7�6 ���h:� .0��6���7.�����7� 8 !���� &�� �9 � .��4 .���������1�� #�0:��� :,� �/��g�� )�6��� '��g�� 3� "� #� i�� �� 0�@���������� �.�� j������ �.�� +��4�� ��c� ����� ����� ����� ��� �1�1� ����� ����� ! .6.5�����?��� �������� �� ����� ����� ��� ����� ����� ����� &�6� : �6�6.��� #�.� 6�;� ��f��.������ +� ;� ��=� +� ;� ��=� /��.40� -�=� �:6.040� +� ;� ��=� +� ;� ��=� � ) ���h:� .0��6�=� ���.���46�.���� ����0.2���!�0:��6�����5f�� !����� .���=.6 ��� �:�.5�6.�� �� ) ��4�.6�:��6� .2��=� ��0�h��0��) �� :���6����0����)��0���� .5��=� �� �=���4 .���6 ��3 � .7�&&� ��� ��4 �! �: ��� ���! �::.���"�66� ��� �� ��� ���� .6� =� � 6 �� 7. 6� 5 �:� �7� 6 �� �@4��5��� �� 6.�.2� � 0�����0��6� ���� .�6� 54�64 ��� �:� �6.�� ��.f��=���.����04�5 .����65��=� ��������55� �.���6�� � 0����6���������c����#����.�� � =� ��� �=��.�� ���<���.���� �:� �6��:��6�������; ����� ����.����7��.��� �����=� �6 �� :���6��� =.6 ���50�h���50� :�5.����������4�;��������)��0��� .5��=� � � ?� 6����������56�<� �������� .5��=� � � ?� 6����6�1��50� �.� 6� 7 �0� �.�� 4 7�5������ �0�.�.���:� 6��7� 6 �� .5��:���6�=� � .�5� :� �6��� =.6 � �.��� ( �.�� ���� 6 �=� ;.��� � =� �� 6�f��� 7 �0�= ���� :��6�� � � :� � 6 ��60��6� :�6�6��=� � � �=���4 .��� �<.� �� ������ 6.�.2� �0�����0��6����� .�6� 54�64 ����:� �6.�� � �.f�� =���.���� 04�5 .��� �65�� =� �� ����� �55� �.��� 6�� 3�<. � ���� ,�@4�� �������� "�6�6�� 64<� � �5?�� %.�0��6�� =� �� :���6��� =.6 � ��� 50� h� ��� 50� :�5.��� ��� ��� �56�<� �� ������ "�6�6�� =� � � ?� 6������������4� ;�.��6 �� �0��;�� ��)4<� �����7��.������?� �� ;��=�.� 6�=� ��6�f���7 �0� 6 ��= ����:��6��/4 6� ��=� �� �=���4 .��� �<.� �� ������ 6.�.2� �0�����0��6�����.�6� 54�64 ��� �:� �6.�� � �.f�� =���.���� 04�5 .��� �65�� =� �� ����� �55� �.��� 6�� /������ ����8� �<� �������� �� &�#� . ����������� &�#� . �����=� ��:���6���=.6 �1��50�h���50� :�5.����������56�<� �� ������ �� &� #� . ����� =� � � ?� 6��� ��� ��� ���4� ;�� ���1� = .��� �� &� #� . ����� =� � � ?� 6������������4� ;�����1��#����;.�������� 6 �=�;.����=� ��6�f���7 �0�6 ��= ����:��6��� /4��<����=� �� �=���4 .���3 � .7�&� �� ������ 6.�.2� �0�����0��6�����.�6� 54�64 ����:� �6.�� � =� �� ����� �55� �.��� 6�� �72��� �6� ���� ����c��� /4��<���� �5?�� �� &� 04������ =� � �=�� ��� ��� ��< 4� ;�����1��/4��<����=� � � ?� 6����������: .������1��#����;.��������<.�0� �=�.� 6��7� 04��<���� =� �� 6�f��� 7 �0� 6 �� ��6. �� :��6�� �76� � � ?� 6.��� �7� :�� �� 04��<���� :���6 � =� �� .�5� :� �6���.�6��6 �� �.����� ��=� �6 ��6 . ��5 �:��7�6 �� �@4��5����� 6.�.2� �0�����0��6����� .�6� 54�64 ��� �:� �6.�� � =� �� ����� �55� �.��� 6�� ,�@4�� �6� ���� �������� ) . 6;� 7.?�� ��; � ���� ����.�� ��7�� &�� ���c�=� ��6 �� :���6���=.6 ���50�h���50� :�5.������������4� ;�����1� .��!"�d�������4� ;�����1�.��!"������������4� ;�����1�.��!"����� �� .5��=� � � ?� 6��������� /�;�����/�;�k����/�;�����1�.��!"���!"������!"��� � :�56.?��;� .5��=� � � ?� 6����6�1��50� �.� 6�7 �0� �.�� 4 7�5������6 �� �0�.�.���:� 6��7�6 �� .5��:���6�=� �.�5� :� �6���=.6 � �.���( �.�� ;.�������� 6 �=�;.����=� ��6�f���7 �0�6 ��= ����:��6��) �� :���6����4 ��)��4 �� .5��=� �6 ��7�4 6 � 5 �:� �7� 6 �� �@4��5��� �� 6.�.2� � 0�����0��6� ���� .�6� 54�64 ��� �:� �6.�� � �.f�� =���.���� 04�5 .�����65��=� ��������55� �.���6��,�@4���6�������������)=��6;���;������ ����.�� ��7�"� .9�� =� ��6 �� :���6���=.6 ���50�h���50� :�5.���������/�;�<�6 �.��!"������!"�������������: .�� .��!"1�.��6 �� �0��;�� ��)���4 �=� � � ?� 6����������4�;�.��!"�d��1��4�;�.��!"���������4�;�.�� !"1�� .5��=� � � ?� 6����6�1��50� �.� 6�7 �0� �.�� 4 7�5������ �0�.�.���:� 6��7�6 �� .5��:���6� =� �.�5� :� �6���=.6 � �.���( �.��;.�������� 6 �=�;.����=� ��6�f���7 �0�= ����:��6�� ���� #6�6. 6.5�������; . ��7���6�#6�6. 6.5�������; . ��7���6�#6�6. 6.5�������; . ��7���6�#6�6. 6.5�������; . ��7���6����� � /#)�)�!�����/.5 � �76�$h5�������%/ )�=� ��4 ���6��0�� 4 ��6 ��?� .�6.����7�0������6���7� 6 ��60��6 ��) ��60��6�0��� �=� ��5�0:� ����6�"���������) ����6��=� ������;2��� 6�6. 6.5���;� 7����=.��� 5�0:46� � :�5f���� /#)�)!�� ���� 6 �� ��6�� =� �� 6�6. 6.5���;� ����;2��� 7����=.��� 6 �� �'�+��6�5 �.@4������6 �� .��.7.5��5���7�0�����.77� ��5� �=� ���94 6���<;�%4�5��l �/4�6.:��� �����)� 6� � � 4�6 �����%. 54 � 4�6 �����%. 54 � 4�6 �����%. 54 � 4�6 �����%. 54 .�� .�� .�� .�� ���� ���� � 4�6 � 7 �0�)�<����� �?������ 6 �6�� �.������ 6 �=�;.��� ��7�)���0��� .5��=� �����1�k����� 6���� ������ �.������ 6 �=�;.��� ��7�04 6� ����� &�#� . ������=� �������6� ����k�1����6� ������ �.�� ���� 6 �=�;.��� ��7��� �� .5��=� �������k������6� �������� �.������ 6 �=�;.��� ��7�)���4 �=� �� 1�c��k������ 6� ����� � :�56.?��;� .��5� ���7�5 �::.���:�66� ����� &��5� ���7�5 �::.���:�66� ����� �c� ,� �.���6����� � �.�� ���� 6 �=� ;.��� � �7� )�� �0���=� �� ��� �e� 6� ���k������ 6� ����� 64<� � ;.���� �7� :�6�6��=� � �e��c� 6� ������� 6 �=�;.����=� ������ 6� ������ �.������ 6 �=�;.��� ��7��� �� .5��=� ����c��k� ���c�6� �������� �.������ 6 �=��7�)���4 � .5��=� ��1�e��6� ���k������6� ����� � :�56.?��;��&��5� �� �7�5 �::.���:�66� ��1��� �.������ 6 �=�;.��� ��7�)���0��� .5��=� �����1�k������6� ������ �.������ 6 �=� ;.��� � �7�04 6� �� ��� &� #� . ������=� �� ���c�k�1���� 6� ����� ���� ���� 6 �=� ;.��� � �7� 04��<����=� ��������6� ���k������6� �������� �.������ 6 �=�;.��� ��7�)���4 � .5��=� ��1�c��k� ���e� 6� ����� � :�56.?��;��8 � �� �� .��5� ���7� �5 �::.���:�66� ����� �.������ 6 �=�;.��� ��7�)�� �0���=� �����c�k����c�6� �������� �.������ 6 �=�;.��� ��7��� �� .5��=� �������k�c����6� ����� � :�56.?��;�� � )�<������"� 7� 0��5���7��.77� ��6�5 �: �4��� �7�4 �5 �::.���:�66� � ��4 .���������1��6� 8 !�� �� &�� �9 � .� ! �:� !�::.���:�66� ���� !�::.���:�66� ���� )��0��� /4 6� �� �� �� )��4 � )��0��� "�6�6�� �� �� )��4 � +� .�6;� �.��� ����� �� &� #� . ����� � &� �� ���c� "� .9�� �.��� ����� %.�0��6� � &� � ���c� "� .9�� #�=.��m� ) �� :���6. �����6�� ��m�m��� ��m��m��� ��m�m�1� ��m�m�1� ��m�m��� ��m��m��� ��m�m�1� ��m�m�1� ! �:� �4 �6.��� e�� c1� ���� ��� e�� ce� ��1� �e� ,� ?� 6.��� ��6�� ��m��m��� ��m�m�1� ��m�m�1� ��m�m�1� ��m��m��� ��m�m�1� ��m�m�1� �1m�m�1� ( �.��*.���� �6� ����� ���1� ����� ����� 1�c�� ���e� �e��c� ��c�� 1�e�� #6 �=�;.���� �6� ����� ����� 1���� ����� ����� ����� ����� ���c� ����� $*� ���1� ��1�� ���c� 1��1� ���e� �1���� ��ce� 1��e� -#%������� ����� ���c�� ���1�� ������ ������ ������ ������ ������ !+��g�� ����� ����� ����� ����� c���� ����� ����� ����� � !��6.�4�6.��� ! �:� !�::.���:�66� ��1� !�::.���:�66� ���� )��0��� /4 6� �� /4��� <���� )��4 � )��0��� �����=� �� �� �����=� +� .�6;� �.��� ����� �� &� #� . ����� �� &� /4����� "� .9�� �.��� ����� �� � &� � ����c� �� #�=.��m� ) �� :���6. �����6�� ��m�m��� ��m��m��� �m�m�1� ��m�m�1� ��m�m��� �� ��m�m� 1� �� ! �:� �4 �6.��� e�� c�� ��� ��� e�� �� ���� �� ,� ?� 6.��� ��6�� ��m��m��� ��m�m�1� ��m�m�1� �m�m�1� ��m��m��� �� ��m�m� 1� �� ( �.��*.���� �6m ��� ���1� ���c� ������ 1�c�� ���c� �� ����� �� #6 �=�;.���� �6m ��� ����� 1���� ����� ���e� ���c� �� c���� �� $*� ���1� ����� ����� 1��1� ���c� �� ����� �� -#%������� ������ ������ ��1��� ����1� ������ � ������ � !+�g�� 1���� ����� ����� e���� ����� � ����� � � �e� ��4 �! �: ��� ���! �::.���"�66� ��� )�6���: ��456.?.6;��7��.77� ��6�5 �::.��� �@4��5� �=� ���6� 0.����<;� .5���@4.?����6�;.����� $*�� = .5 �=� �5��54��6��� 7 �0�;.�����7�5�0:����6� 5 �: �� .5���@4.?����6�;.����=� ��.77� ��6�4��� � �.77� ��6� 5 �::.��� �@4��5�� �)�<���1���) �� .� � 6� $*� ������� 6� �����=� � �5� ���� 7 �0� 6 �� 5 �::.��� �@4��5��)���0���b�"�6�6��b��� ��b�)��4 ��= .5 �=� �7����=���<;�)���0���b�/4 6� �� b��� ��b�)���4 ���c��e�6� ������) ����=� 6� $*������1�6� �����=� ��<6�.����7 �0�6 ��5 �::.��� �@4��5��)���0���b������=�b��� ��b������=��&�5�4 .����7�04 6� ���4 .��� �<.� �� ���.��!"������ !"1� .�5 �� ��� $*� ����� 6�� ���1�g� 5�0:� ��� 6�� 7� 0� l � :�66� ��!"������ 6 �� �6 � � ����� .�5�4 .����7�:�6�6��.��!"��.�5 �� ��� $*��1����g��4 .���������1��� ���� $5���0.5�����; . $5���0.5�����; . $5���0.5�����; . $5���0.5�����; . ���� $5���0.5 ��7� ; 6�0�: ��456.?.6;��7� 7�4 � 5 �::.��� �@4��5� � �=��� .��)�<���1� �?������ 6 �6� 6 �� � � � �64 �� =� � �.77� ��6� 7� � �.77� ��6� 5 �::.��� :�66� � �� ) �� .� � 6� � � � �64 �� �)f�� 1c�1��� �����=� � �5� ����7 �0��)���0���b�:�6�6��b��� ��b�)���4 �5 �::.���:�66� ����7����=��� <;�)���0���b�/4 6� ��b��� ��b�)���4 �5 �::.���:�66� ����)f�����1��� ������)���0���b�/4 6� �� b�/4��<����b�)���4 �5 �::.���:�66� ��1��)f��������� ������)���0���b������=�b��� ��b������=� 5 �::.���:�66� ������?��6 ����=� 6�� � � �64 ���)f��������� ������)�6���?� .�<���5� 6�=� ���=� � .��5 �::.���:�66� ��1��)f�����11�� �����7����=���<;�5 �::.���:�66� ����)f������1�� ������) �� .� � 6�6�6���?� .�<���5� 6��)f���1���c� ���=� � �5� ����7 �0�5 �::.���:�66� ��������0.� 6�<�� �4��6�� .� � � ����5� 6��7�:�6�6���) �� .� � 6�� � �0� �.��=� ��<6�.����7 �0�5 �::.���:�66� �� �� �)f����ccc�� ����� 7����=���<;�5 �::.���:�66� �1� �)f���111��� ������5 �::.���:�66� ��� �)f�� ���e��� ������! �::.���:�66� ������?��6 ����=� 6�� � �0� �.���)f����1�c� ������) �� .� � 6� 0� �.����<���7.6�5� 6� �6.����/�! ��=� �7�4���.��5 �::.���:�66� ��1��������7����=���<;�5 �::.��� :�66� �� �� �������� 5 �::.��� :�66� �� �� ����1��� �� 0� l � :�66� �� �5��6 ���� !"�� ��?�� 6 �� ��=� 6� /�! ���������4 .�������;�� �5 �: �:� .���� � )�<��� 1�� .5�� �@4.?����6� ;.����� 5� 6� ���� �64 �� �7� 7�4 � 5 �::.��� :�66� � � �4 .��� ������1� �6� 8 !���� &�� �9 � .� "�66� �� $*� �6� ����� ( � � �64 �� �)f�� ����� +� .�<���5� 6� �)f�� ����� ( � �0� �.�� �)f�� ����� /�! � !"�� �c��e� ���1��� ����1�m�� ���e��m�� ����� !"�� ������ 1c�1��� �1���cm�� ��ccc�m�� ���1� !"1� ����1� ������� ����1�m�� �111��m�� ����� !"�� ����1� ������� ����1�m�� ��1�cm�� ����� � " .5���)��0���)f����f�����/4 6� ���)f����f�����/4��<�����)f����f������� ���)f������f�����"�6�6���)f����f��������4 �� )f��1����f���� � !��5�4 .��!��5�4 .��!��5�4 .��!��5�4 .������ ���� � �0�6 �� � 4�6��7�6 �� 64�;��.6�0�;�<��5��5�4����6 �6�7�4 �5 �: �<� ���6 ���5 �::.���:�66� � � 45 � � � � !"�a� ) �� :���6��� �0��� .5�� ��.��� ����b/4 6� �� ��� &� #� . ������ b� �� �� .5�� �� &�� ���c��b�) �� :���6����4 � .5���"� .9��d�!"��a�)���0��� .5��b�"�6�6���%.�0��6�b��� �� .5�b)���4 � .5�d�!"1�a�)���0��� .5��b�/4 6� ����� &�#� . ������b�/4��<������� &�04������b )���4 � .5��� ���� ���0.5���;� 7�� .<��������5���0.5���;�: �7.6�<���5�0:� ���6��6 ���h. 6.����)�� �0���b������=�b��� ��b������=�:�66� ���,�=�?� ��!"1�=� �7�4���6 ��0� 6�: �7.6�<��������%4�� 6��� �=.����7�7�4 �5 �: �.����;�� �.��6 �� �0��:.�5���7������5 �::.���.�6�� .6;�����: ��456.?.6;� =.���<��.�5 �� ����0� ���0:��;0��6��::� 64�.6;�7� �0��������7�0������<� �=.���<��5 ��6������� �6� 6 �� �0��6.0���4��6�� .�5 �� ���: ��456.����7� .5���:�6�6���04 6� ������04��<����6 ��7���� �����46 .6.����� �54 .6;�=.���<��� 5� 6�.����7� �6 ��7� 0� �����6 ����6.���� ���= ����� ��� ,� �.���6����� �7� ��5� � �7� ��5� � �7� ��5� � �7� ��5� ����� ���� �72����/������/�������f� �����,�0.���/��������.������/��/��,�@4������c���������� ��/4������ � ! � �� #6 ���6 �.��� �7� "4� � � k� �.� ���� � �� 5 � : �� �00�� .�� �������� �� �� &�� (�2.:4 �� � ��=�6�� &��"��#������#.�� ������!��#��#� �7���ec���$77�56��7�=.�6� � ���40� �����.6 ������5���0;� ����: ��456.?.6;��7� 455���.���5� ��� ��$h:6���� .5�������������� �2.2��/������������3��/��,�� � 0����������%�?���:0��6��7���6� ��6��! �::.���"�66� ��7� �!�� 6��� #��.��� �7� �������� � ���.� 6� �� 0� � $h. 6.��� )�� �0���� �����=�� �����=� "�66� ��� ���4��� � �� 5 � �:� 6������������� ���0;�%.?. .������������ ��� .54�64 ��� � �� 5 �&� 6.646��� (�2.:4 ��::���e������ ��#���������� ��4 ��4��7�#6�6. 6.5 ���������#6�6. 6.5���*�� <��f��7��������� ���������� ��4 ��4� �7�#6�6. 6.5 ��/.�. 6 ;��7�"����.����% �f����������� �� $�.� ��#��/���/��#��,� �.������#��#.f�� ��/������ 0�������/��/�� ��3� .0���ec���&���6.7.5�6.����7� 5�� 6 �.�6 � 6�� :4� �� : ��456.��� =.6 � :�5.��� �7� ��5�� 6�� : � ��6� 7� 0.��� ; 6�0 �� ���4��� �:� 6��7�6 ���� .54�64 ���$5���0.5 �%.?. .������ &����;��<:4 ��:���� ,�@4��� ��� 3�� (�� /�� '��� /�� 3�� �� � ��� /�� #�� & ��0� ���� /�� ��� 3 � �0�� ������ /��� �� .5�� !4�6.?�6.������6 ���.6.������������ � .5�� � �� 5 �&� 6.646���(�2.:4 ������� & ��0��#���ee���#�.���46 .��6� 6�64 ��77�56.���: ��456.?.6;��7�:4� � � .�� 6 ��0�9� �����:�6��6.���:4� �� � �=.��� � �� �� &��� ��?��5� � .�� "4� � � � �� 5 � .�� �������� �� " �5���.�� � �7� 6 �� ���� ��6.����� =� f �:� ��� :4� � �� �4��� ��c�� �ece�� �� &�� (�2.:4 �� "4<�. ��� <;� &! &#�)�� "�6��5 � 4����� ��" ��� �����1����&��.��� 3�<. � 3�� ,�� ���� /�� i�� ,�@4��� ������ ��4� ! � � � �� 4�.f� 3���f�= ��� �/��� �� " ��456.��� )�5 �����;��7�"�6�6����� 6���.6.����)! !���� &��(�2.:4 ���������� �� 34 62��-��)���-��+���������)�� ��"�5f������ ��(��,��76���ec���! �:� �6�6.�� �7� ��77.5.��6��.6 ����� 4 ��� .�� ,45f�� �%��� ����� '.6 ����� .�� ! �:� " ��456.���� ::��e��1���� �#��!##�� ###��� /��. ���� /�������/�� �� &�� ����/�����8� �<�� ������ " ��456.��� 6�5 �����;� �7� �.�5 �: �� �.� ���� � �� 5 � !��6 ����� &����;��<:4 ��(�2.:4 ������� /�������/�� �� &���/�� #�� & ��0��/����� ���� ;� � ����/��/�� � 0���� ������3 . .� " �94f6.�,�6<�.� �,���<��f� ��� �� ��6�5 �����;��� �6 � ��.6.���� �������� � �� .54�64 ��� � �� 5 � &� 6.646��� (�2.:4 ������� �5 .���3���������-��/�� �<� 6 ���e����( �.�����40� ��7�6 ����=������6 �:.5 ����?���� ����������� �1��� � 0����/��#���/�����#�66� ��'�����40�����/�� ��,;�� �����c������6��3 . .�" �94f6.�"� .5 .6;�� �������� �&� 6.646���7�'45��� ��� .54�64 ���/;0�� .�� �� # � 0��� #�� '�� ���� �� " � ���� �eee�� $77�56 � �7� � <��.�� � ���� 0��4 .��� ���� 04��<���� � .�4�� .�5� :� �6.��� �7� : ��456.?.6;� ���� �.6 ����� 4:6�f�� �7� �� .5��= ��6� 5 �::.��� ; 6�0�� �.� � �4 5��)�5 �������������������� 8� �<��/������/�� ��&��/��������/������f<� ��/��#�����0���/������ 0��������������0�������� #6�64 � �7� �.�5 �:� : ��456.��� .�� �������� �� �.� ���� � �� 5 � !��6 ��� �� &�� ��;��<:4 �� (�2.:4 ������� microsoft word 1 bangladesh agron. j. 2017, 20(2): 1-9 sitesitesitesite----specific nutrient management for irrigated ricespecific nutrient management for irrigated ricespecific nutrient management for irrigated ricespecific nutrient management for irrigated rice in in in in south central region of bangladeshsouth central region of bangladeshsouth central region of bangladeshsouth central region of bangladesh m. a. a. mamunm. a. a. mamunm. a. a. mamunm. a. a. mamun1*1*1*1*, , , , s. a. islams. a. islams. a. islams. a. islam2222, , , , mmmm. s. s. s. s.... islamislamislamislam2222, , , , a. j. mridhaa. j. mridhaa. j. mridhaa. j. mridha2222 and mand mand mand m.... aaaa.... salequesalequesalequesaleque2222 1bangabandhu sheikh mujibur rahman agricultural university, gazipur 1706, bangladesh 2bangladesh rice research institute, gazipur 1701, bangladesh *corresponding author, e-mail: aamamunbrri@yahoo.com (received: received: received: received: 16 november 2016, accepted: accepted: accepted: accepted: 9 december 2017) keykeykeykey wwwwords:ords:ords:ords: irrigated rice, nutrient omission, optimum yield, ssnm abstractabstractabstractabstract a site-specific nutrient management (ssnm) field trial was conducted for irrigated rice using five fertilizer treatments: i) omission of n, ii) omission of p, iii) omission of k, iv) npk and v) farmers’ practice (fp). substantial variation in the native n, p, and k supply was found among farmers’ fields. the indigenous soil k produced 4.5 to 5.0 t ha-1 but native p and n gave only rice yield of 3.5 to 4.0 t ha-1. the highest grain yield (6.0 to 7.5 t ha-1) was obtained from balanced fertilization, followed by fp (4.0 to 5.0 t ha-1).the optimal grain yield at faridpur was obtained by using n, p and k at 135, 8 and 49 kg ha-1; 139, 9 and 42 kg ha-1; and 140, 10 and 43 kg ha-1 for high, medium and low land rice, respectively. however, for gopalgonj district fertilizer doses of n, p and k were 140, 11 and 38 kg ha-1; 142, 10 and 42 kg ha-1; and 138, 10 and 49 kg ha-1; and for madaripur district, 126, 8 and 46 kg ha-1; 120, 7 and 38 kg ha-1; and 99, 6 and 27 kg ha-1 for high, medium and low land rice, respectively. these predicted fertilizer doses increase farmers’ income and protect environment from pollution. introductionintroductionintroductionintroduction fertilizer is one of the most important inputs and successful production of boro rice depends on fertilizer management. fertilizer accounts for about 20 percent of input costs in rice production the biggest cost after labor (clayton, 2010). for modern rice varieties, bangladesh agricultural research council (barc) has published a fertilizer recommendation guide and bangladesh rice research institute (brri) adhunik dhaner chas booklet (frg, 2012; brri, 2013). to ensure that essential plant nutrients are provided in optimal amounts and readily available during crop growth, site-specific nutrient management (ssnm) was developed by the international rice research institute (irri, 2008). in ssnm, the plant’s need for n, p or k fertilizer is determined from the gap between the supplies of a nutrient from indigenous sources, as measured via a nutrient omission plot, and the demand of the rice crop for that nutrient, as estimated from the total nutrient required by the crop to achieve a yield target for average climatic conditions. so, ssnm is a low tech, plant need based approach for optimally applying nitrogen, phosphorus and potassium fertilizers to rice when they are needed (irri, 2007). the purpose of this research was to recognize spatial variability in soil fertility depending on response of indigenous nutrient elements and calculate the amount of fertilizer correctly for developing site-specific nutrient management package for rice production in low ganges river floodplain of bangladesh. 2 mamun et al. materials and mmaterials and mmaterials and mmaterials and methodsethodsethodsethods farmers’ participatory ssnm experiment was conducted on 72 farmers’ fields in low ganges river floodplain of agro ecological zone (aez) -12 of bangladesh. the common cropping pattern was boro (january to may) fallow – t.aman (july to november). soils of the region are silt loams and silty clay loams on the ridges and silty clay loam to heavy clays on lower sites. five fertilizer treatments, i.e., nitrogen omission (pk), phosphorus omission (nk), potassium omission (np), balanced fertilizer (npk) and farmers’ practice (fp) were used (table 1) table 1. description of experimental treatments no. treatment applied nutrients description 1. nitrogen omission (-n) pk pk-based fertilizer recommendation 2. phosphorus omission (-p) nk nk-based fertilizer recommendation 3. potassium omission (-k) np np-based fertilizer recommendation 4. balance fertilizer (npk) npk npk-based fertilizer recommendation 5. farmers’ practice npk farmers’ own fertilizer practice two sites (site-i and site-ii) within each district (faridpur, gopalgonj and madaripur) were selected for trial. from six sites, four farmers (each farmer represented one replication) were selected from each of high, medium or low land. so, selected numbers of farmer were 24 (12 from site-i and 12 from site-ii) from each district. the experimental design was split-split plot (mentioned main and sub plot) with four replications. farmers cultivated brri dhan29 in faridpur and gopalgonj but brri dhan28 in madaripur district. the age of seedlings for transplanting varied from 40 to 55 days. transplanting time ranged from mid-january to last week of february. blanket doses of other nutrients were included in all treatments to prevent deficiencies other than nitrogen (n), phosphorus (p), or potassium (k). in this trial, n, p and k were used at 147, 20 and 50 kg ha-1 in the form of urea, triple super phosphate (tsp) and muriate of potash (mop). the tsp and mop were applied during final land preparation but urea was top-dressed in three splits (15, 30 and 50 days after transplanting). intercultural operation and irrigations were similar in all locations. monitoring was done through frequent field visits and keeping close contact with respective farmers during the crop-growing period. calculation of optimum fertilizer ratescalculation of optimum fertilizer ratescalculation of optimum fertilizer ratescalculation of optimum fertilizer rates optimum n, p and k doses were calculated following driessen (1996): n = [(ynpk – ypk)/ nu] × 18 [1] p = [(ynpk – ynk)/ pu] × 2.5 [2] k = [(ynpk –ynp)/ ku] × 20 [3] where, ynpk = yield in npk plots, ypk = yield in n omission plot, ynk = yield in p omission plot, ynp = yield in k omission plot, nu =n-use efficiency (40%), pu = p-use efficiency (60%), and ku = k-use efficiency (80%) (brri, 2004). grain yield was harvested at maturity and was adjusted to 14% moisture content [gmk-303rs (g-won hitech co., ltd, korea)] was used. crop data were analyzed using the cropstat 7.2 software (irri, 2015). 3 site-specific nutrient management for irrigated rice results and results and results and results and ddddiscussioniscussioniscussioniscussion grain yieldgrain yieldgrain yieldgrain yield faridpurfaridpurfaridpurfaridpur grain yield of rice on different land types (l) was not statistically significantly different. similar grain yield was obtained from high, medium and low lands. the individual effect of site (s) as well as that of l × s interaction on yield was statistically significant. the highest grain yield was recorded from low land in site-i. the grain yield was the highest in medium land at site-ii (table 2). effect of fertilizer management (f) was statistically significant on grain yield. the highest grain yield was obtained from balanced fertilization (npk) that produced about 6-.5 t ha-1. in fertilizer omission plots, the highest grain yield was recorded from potassium omission (-k), followed by phosphorus omission plot (-p) but statistically similar yields. the potassium and phosphorus omission plots yielded 4.65 and 4.43 t ha-1, respectively. the lowest yield was obtained from nitrogen omission plot (-n) that produced 3.38 t ha-1. however, the l × f, s × f and l × s × f interactions were not statistically significant in relation to grain yield (table 2). on high land, highest yield was recorded from npk-treated plots, followed by farmers’ practice. in nutrient omission plots, the highest yield was obtained from np (-k) plot. table 2. rice yield as affected by different nutrient management practices at farmers’ field at faridpur district treatments grain yield (t ha-1) high land medium land low land mean site-i site-ii mean site-i site-ii mean site-i site-ii mean n (pk) 3.50 3.23 3.36 3.30 3.17 3.24 3.92 3.00 3.47 3.38 p (nk) 4.29 4.44 4.37 4.55 4.69 4.62 4.42 4.19 4.30 4.43 k (np) 4.55 4.24 4.40 4.46 4.93 4.70 5.08 4.64 4.86 4.65 npk 6.40 6.31 6.36 6.40 7.15 6.78 6.94 6.23 6.58 6.58 fp 5.59 4.77 5.19 5.44 5.16 5.31 5.61 4.98 5.29 5.26 mean 4.86 4.60 4.83 5.02 5.19 4.61 cv (%) 10.4 lsd (0.05) land (l) ns site (s) 0.19 l × s 0.34 fertilizer (f) 0.31 ns = not significant, fp = farmers’ practice gopalgonjgopalgonjgopalgonjgopalgonj grain yield was not statistically influenced by the individual effect of site (s) and land type (l) as well as by l × s interaction (table 3). statistically similar grain yield was obtained from both sites in all land types. again, higher grain yield was obtained from high land than from medium land. on the other hand, effect of fertilizer management (f) was statistically significant on grain yield. the highest grain yield was obtained from npk, followed by farmers’ practice. the highest grain yield was recorded from potassium omission plots (-k), followed by phosphorus 4 mamun et al. omission plots (-p). these two treatments produced statistically similar yields. around 3.37 t ha-1 yields were recorded from -n plots, whereas more than 4.0 t ha-1 yields was recorded from -p and -k plots. however, the l × f, s × f and l × s × f interaction effects were not statistically significant in relation to grain yield (table 3). irrespective of land type, highest grain yield was recorded from balanced fertilizer (npk)-treated plots. in missing-nutrient plots, the highest yield was obtained from potassium omission (-k) plots, followed by phosphorus omission (-p) plots. the lowest yield was recorded from nitrogen omission (-n) plots in all cases (table 3). table 3. rice yield as affected by different nutrient management practices at farmers' field at gopalgonj district treatments grain yield (t ha-1) high land medium land low land mean site-i site-ii mean site-i site-ii mean site-i site-ii mean n (pk) 3.48 3.60 3.54 3.44 3.29 3.37 3.25 3.11 3.18 3.37 p (nk) 4.58 4.57 4.58 4.66 4.05 4.36 4.50 4.18 4.34 4.43 k (np) 4.70 4.82 4.77 4.50 4.81 4.66 5.19 4.26 4.73 4.72 npk 7.31 6.87 7.10 6.76 6.74 6.75 6.63 6.72 6.68 6.85 fp 5.09 5.38 5.24 5.22 5.33 5.28 5.16 5.50 5.33 5.29 mean 5.04 5.05 4.91 4.84 4.95 4.76 cv (%) 9.6 lsd(0.05) land (l) ns site (s) ns l × s ns fertilizer (f) 0.26 ns = not significant, fp = farmers’ practice madaripurmadaripurmadaripurmadaripur the effect of land type (l) on grain yield was not significant but site (s) effect was significant. the l × s interaction was not statistically significant for grain yield (table 4). the highest grain yield was obtained from site-i in all land types. more than 4.5 t ha-1 grain yields were recorded from site-i but less than 4.0 t ha-1 from site-ii. effect of fertilizer management (f) on grain yield was statistically significant. the highest grain yield was obtained from balanced fertilization (npk), which produced more than 5.5 t ha-1. in nutrient omission plots, the highest grain yield from potassium omission plots (-k) was followed by phosphorus omission plots (-p). both the treatments produced more than 4.0 t ha-1. around 3.0 t ha-1 yields were recorded from -n plots, whereas more than 4.0 t ha-1 yield was recorded from -p and -k plots. the l × f, s × f and l × s × f interaction effects were statistically significant for grain yield. the highest yield was obtained from balanced fertilizer in all land types, followed by fp. in fertilizer omission plots, the highest yield was obtained from -k, followed by -p plots. in high land, highest yield was obtained from npk fertilizer that yielded 7.08 and 4.84 t ha-1 at site-i and ii, respectively. potassium omission plots produced the second highest yield in high land, followed by -p plots. in medium and low lands, highest yield was recorded from npk plots. around 6.0 t ha-1 grain yield was obtained from npk fertilizer and 4.5 -5.0 t ha-1 from -k plot. the lowest yield was recorded from nitrogen omission plots (-n) in all cases. this trend was also true for low land. 5 site-specific nutrient management for irrigated rice table 4. rice yield as affected by different nutrient management practices at farmers' field at madaripur district treatments grain yield (t ha-1) high land medium land low land mean site-i site-ii mean site-i site-ii mean site-i site-ii mean n (pk) 3.26 3.02 3.15 3.34 2.71 3.03 3.58 2.97 3.27 3.15 p (nk) 4.32 3.74 4.03 4.17 3.65 3.91 4.44 3.85 4.15 4.03 k (np) 4.56 3.72 4.14 4.84 3.54 4.19 4.87 3.91 4.39 4.25 npk 7.08 4.84 5.96 6.29 5.08 5.69 5.97 5.00 5.48 5.71 fp 5.07 4.14 4.61 5.56 4.18 4.87 4.49 4.07 4.28 4.59 mean 4.87 3.89 4.86 3.83 4.67 3.96 cv (%) 10.3 lsd(0.05) land (l) ns site (s) 0.14 l × s ns fertilizer (f) 0.22 l × f 0.39 s × f 0.32 l × s × f 0.55 ns = not significant, fp = farmers’ practice the npk treatment produced the highest grain yield at all locations. the balanced fertilizer treatment plots gave 95, 49, 42 and 25% higher grain yield at faridpur (table 2); 103, 55, 45 and 29% at gopalgonj (table 3) and 81, 42, 34 and 24% at madaripur (table 4) than omission of n (pk), p (nk), k (np) and fp, respectively. the highest grain yield was obtained to balanced fertilization (optimum n, p and k) that produced more tillers and number of panicles per square meter and highest thousandgrain-weight as compared with pk, nk, and np treatments. pham et al. (1999) reported that more balanced fertilization increased n-uptake and n-use efficiencies. nath et al. (2012) was also found that npk fertilizer-treated plots gave higher grain yield due to more panicles m-2 and thousand grain weight compared with omission of n, p and k-treated plots. among omission plots, the highest grain yield was recorded from k omission plots. the response of soil native potassium was mentionable (4.5 to 5.0 t ha-1) and thus in k omission treatment; yield was the second highest (tables 2 to 4). so, the response of soil native potassium was better than phosphorus and nitrogen omission plot. nath et al. (2012) also reported that the response of soil native potassium was remarkable and produced yield similar to that of npk-treated plots. to produce one ton of rice, 20 kg k ha-1 is required (dobermann and white, 1999). the plots without application of p fertilizer gave lower grain yield than npk and k omission plots. phosphorus promotes tillering, root development, early flowering and ripening. to produce one ton of rice grain, 2.5 kg p ha-1 is required (dobermann and white, 1999). lower grain yield in p-omission plots might be as a result of production of minimum 6 mamun et al. number of panicles m-2 and less grains panicle-1. the n omission plots produced the lowest grain yield, which was around 3.0 t ha-1. insufficient n supply did not meet the crop demand for other nutrients, such as p, k and other microand secondary nutrients. to produce one ton of rice, 18 kg n ha-1 is required (dobermann and white, 1999). brri dhan29, a long duration variety, produced around 6.0 t ha-1 at faridpur and gopalgonj (tables 2 to 4). in contrast to, brri dhan28, a short duration variety, yielded around 5.0 t ha-1 at madaripur (tables 2 to 4). response of initial soil nutrient to grain yieldresponse of initial soil nutrient to grain yieldresponse of initial soil nutrient to grain yieldresponse of initial soil nutrient to grain yield the relationship between initial soil n and grain yield in n omission plots (pk) was significant (p<0.00) and positive at all locations. so, with the increases of soil n, regression analysis showed increased grain yield in missing-n plots (fig 1). the relationships between soil n and yield of n omission plots were: faridpur : grain yield = 11.103 soil n + 2.2157, r2 = 0.4993** gopalgonj : grain yield = 10.269 soil n + 2.2207, r2 = 0.3976** madaripur : grain yield = 16.574 soil n + 1.378, r2 = 0.522** for phosphorus omission plots, a significant and positive relationship was obtained between soil p and yield of p missing plot (p<0.01). regression analysis demonstrated increased grain yield was obtained with increases in soil p (fig 2). the relationships between yield and soil p were: faridpur : yield = 0.0994 soil p + 3.7441, r2 = 0.4216** gopalgonj : yield = 0.0624 soil p + 3.5376, r2 = 0.3553** madaripur : yield = 0.0731 soil p + 3.3352, r2 = 0.3968** the grain yield response in k omission plots was statistically significant. with increases in soil k, regression analysis showed increased grain yield (fig 3). the relationships between yield responses with soil k were: faridpur : yield = 11.305 soil k + 2.035, r2 = 0.5243** gopalgonj : yield = 5.5439 soil k + 3.3888, r2 = 0.3507** madaripur : yield = 26.162 soil k + 0.8939, r2 = 0.5464**. all the b values were significant (p<0.01). fig. 1. relationship between grain yield in nutrient omission plot and indigenous soil n supply during boro season ** = significant at 1% level. yield = 11.103 soil n + 2.2157 r 2 = 0.4993** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 0.05 0.1 0.15 0.2 initial soil n (%) g ra in y ie ld ( t h a -1 ) yield = 10.269 soil n + 2.2207 r2 = 0.3976** 0.0 1.0 2.0 3.0 4.0 5.0 0 0.05 0.1 0.15 0.2 initial soil n (%) g ra in y ie ld ( t h a -1 ) yield = 16.574 soil n + 1.378 r2 = 0.522** 0.0 1.0 2.0 3.0 4.0 5.0 0 0.05 0.1 0.15 initial soil n (%) g ra in y ie ld ( t h a -1 ) faridpur gopalgonj madaripur 7 site-specific nutrient management for irrigated rice fig. 2. relationship between grain yield in nutrient omission plot and indigenous soil p supply during boro season ** = significant at 1% level. fig. 3. relationship between grain yield in nutrient omission plot and indigenous soil k supply during boro season ** = significant at 1% level. calculation of optimum fertilizer dosescalculation of optimum fertilizer dosescalculation of optimum fertilizer dosescalculation of optimum fertilizer doses using formulae 1, 2 and 3, optimum fertilizer doses were calculated for cultivating boro rice. the calculated doses of n, p and k were 135, 8 and 49 kg ha-1; 139, 9 and 42 kg ha-1; and 140, 10 and 43 kg ha-1 for high, medium and low land, respectively, at faridpur (table 5). the required fertilizer doses of n, p and k were 140, 11 and 38 kg ha-1; 142, 10 and 42 kg ha-1; and 138, 10 and 49 kg ha-1 for high, medium and low land, respectively, at gopalgonj. the calculated optimum n, p and k dose were 126, 8 and 46 kg ha-1; 120, 7 and 38 kg ha-1; and 99, 6 and 27 kg ha-1 for high, medium and low land, respectively, at madaripur. the calculated doses of n, p and k were lower than applied fertilizer doses at all locations. however, the differences were more prominent in madaripur than that of faridpur and gopalgonj. this might be due to cultivation of brri dhan28 (short-duration) at madaripur but brri dhan29 (long-duration) at faridpur and gopalgonj districts. however, calculated n and k doses were higher (10 to 20 kg ha-1) than farmers’ practice but p was lower (table 5). moreover, farmers’ application of fertilizer was not sufficient for proper plant growth and yield. imbalanced fertilization during boro rice cultivation depletes soil nutrients, leading to a decline in production. therefore, using ssnm fertilizer management practice, farmers could get more profit and also reduce environmental pollution. yield = 0.0994 soil p + 3.7441 r2 = 0.4216** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 5 10 15 20 initial soil p (µg g-1) g ra in y ie ld ( t h a -1 ) yield = 0.0731 soil p + 3.3352 r2 = 0.3968** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 5 10 15 20 initial soil p (µg g-1) g ra in y ie ld ( t h a -1 ) yield = 11.305 soil k + 2.035 r2 = 0.5243** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 0 0.1 0.2 0.3 0.4 initial soil k (meq 100g-1) g ra in y ie ld ( t h a -1 ) yield = 5.5439 soil k + 3.3888 r2 = 0.3507** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 0 0.1 0.2 0.3 0.4 initial soil k (meq 100g-1) g ra in y ie ld ( t h a -1 ) yield = 26.162 soil k + 0.8939 r2 = 0.5464** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 0.05 0.1 0.15 0.2 initial soil k (meq 100g-1) g ra in y ie ld ( t h a -1 ) yield = 0.0624 soil p + 3.5376 r 2 = 0.3553** 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 10 20 30 initial soil p (µg g-1 ) g ra in y ie ld ( t h a )-1 1 faridpur gopalgonj madaripur faridpur gopalgonj madaripur 8 mamun et al. table 5. calculated optimum doses of nutrients under various soil types during boro season nutrients amount of nutrients (kg ha-1) high land medium high land low land faridpur applied to be applied† fp to be applied† fp to be applied† fp n 147 135 105 139 112 140 136 p 20 8 20 9 30 10 40 k 50 49 27 42 25 43 30 gopalgonj n 147 140 151 142 120 138 153 p 20 11 24 10 21 10 32 k 50 38 28 42 27 49 35 madaripur n 147 126 143 120 126 99 130 p 20 8 26 7 31 6 27 k 50 46 25 38 35 27 32 †calculated optimum amount of npk, fp = farmers’ practice conclusionconclusionconclusionconclusion depending on the response of grain yield to the indigenous soil nutrients, it could be concluded that rice soils of faridpur, gopalgonj and madaripur showed spatial variability in availability of n, p and k. however, nitrogen and phosphorus were the most limiting nutrients to increased grain yield in the experimental sites. for optimum grain yield of boro rice, recommendation for farmers of faridpur could be use of n, p and k at 135, 8 and 49 kg ha-1; 139, 9 and 42 kg ha-1; and 140, 10 and 43 kg ha-1 for high, medium and low land, respectively. however, required fertilizer doses of n, p and k were 140, 11 and 38 kg ha-1; 142, 10 and 42 kg ha-1; and 138, 10 and 49 kg ha-1 at gopalgonj; and 126, 8 and 46 kg ha-1; 120, 7 and 38 kg ha-1; and 99, 6 and 27 kg ha-1 at madaripur for high, medium and low land, respectively. a mentionable portion of fertilizer can be saved through adopting site-specific nutrient management (ssnm) technology which can ensure efficient use of nutrients. acknowledgementsacknowledgementsacknowledgementsacknowledgements this research was supported by usaid funded extension of cereal system initiative for south asia (csisa) in bangladesh project of international rice research institute (irri). the authors are grateful to the farmers of singria and khapura of faridpur; podderer char and gobra of gopalgonj; char doulath khan and char doulath khan south of madaripur district for their patience and excellent cooperation through-out the on-farm experiments. 9 site-specific nutrient management for irrigated rice referencesreferencesreferencesreferences brri. 2004. bangladesh rice research institute. soil science division, bangladesh rice research institute internal review report for 2003-2004. pp. 25-27. brri. 2013. bangladesh rice research institute. “adhunik dhaner chash,” 17th edition, pp.10– 72. clayton, s. 2010. “50 years of rice science for a better world – and it’s just the start!” rice today, irri. dobermann, a. and p. f. white. 1999. strategies for nutrient-management in irrigated and rainfed lowland rice systems. nut. cycl. agro-ecosystem 53: 1-18. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka 1215, pp. 01-02. irri. 2007. international rice research institute. site-specific nutrient management [online]. available at www.irri.org/irrc/ssnm. irri. 2015. international rice research institute. http://cropstat-for-windows. software.informer.com/7.2/ irri. 2008. international rice research institute. http://www.knowledgebank.irri.org /ericeproduction/iv.4_ssnm.htm nath, d., f. haque, m. s. islam and m. a. saleque. 2012. farmers’ participatory site specific nutrient management in ganges tidal floodplain soil for high yielding boro rice international conference on environment, agriculture and food sciences (iceafs'2012) august 11-12, in phuket, thailand. bangladesh agron. j. 2015, 18(2): 15-21 effect of sowing date of sweet corn on potato + sweet corn intercropping system a.a. begum, m.n. islam, s.s. kakon, m.a.h.m. kamal1, m.a. aziz and s.k. paul agronomy division, bangladesh agricultural research institute, gazipur agronomy division, rars, burirhat, rangpur corresponding author: luckyshamol6869@gmail.com key words: sowing date, light availability, intercropping, potato equivalent yield, ler, potato and sweet corn abstract an experiment was conducted at the agronomy research field of bangladesh agricultural research institute (bari), joydebpur, gazipur and at regional agricultural research station, burirhat, rangpur during rabi season of 2013-14 and 2014-15 to find out optimum sowing date of sweet corn in potato + sweet corn intercropping system for getting maximum yield and economic return. six treatments viz., simultaneous sowing of potato and sweet corn, sweet corn sown at 10 days after potato planting (dapp), sweet corn sown 20 dapp, sweet corn sown 30 dapp, sole potato and sole sweet corn were tested in this study. sweet corn sown at 20 dpp produced the highest potato equivalent yield (joydebpur: 41.41 t ha-1 in 2013-14 and 42.22 t ha-1 in 2014-15 and rangpur: 42.29 t ha-1 in 2013-14 and 42.52 t ha-1 in 2014-15). the highest gross return at joydebpur tk. 431050 ha-1 and at rangpur tk. 436248 ha-1, gross margin at joydebpur tk. 286805 ha-1 and at rangpur tk. 271985 ha-1 and benefit cost ratio at joydebpur 2.99 and at rangpur 3.01 were observed over the years in the same treatment. in this treatment, tuber yield was reduced 3.4-4.1% in joydebpur and 7.8-8.4% in rangpur due to intercropping. the result indicated that sweet corn sown 20 dapp might be suitable intercrop combination for getting maximum yield and economic return. introduction population in bangladesh is increasing at an alarming rate that demands more food. intercropping system is one of the important approaches of cropping systems by which production can be increased substantially. intercropping system becomes productive and economic only when it is done properly by selecting compatible crops (santalla et al., 2001), by shifting the period of peak demand for growth resources through changing the time of sowing of the component crops (santalla et al., 1999). potato (solanum tuberosum l.) is the third important vegetable crop in bangladesh in respect of area and production (fao, 2008). the area under potato is increasing rapidly and the farmers are gradually adopting it as a cash crop. sweet corn is a unique crop because of its versatile use and low cost per unit production. it is a good source of vitamin c and vitamin a (chrispher et al., 1996) in the human diet either as a fresh or processed product. in addition, sweet corn plants can be used as a green forage crop. the climatic condition in bangladesh is suitable for corn cultivation round the year. but there is a problem in increasing area under sweet corn in the country as it has to compete with a number of crops particularly in the dry season (rabi season). however, the area and production of sweet corn can be increased if it is included as an intercrop with potato. sowing of component crops at different times is an important agronomic approach in intercropping systems for increasing total productivity. but appropriate sowing time of sweet corn as intercropped with potato has not been extensively studied in bangladesh. hence, to find out suitable sowing date of sweet corn as intercropped with potato, this experiment was undertaken for getting maximum yield and economic return. materials and methods 16 begum et al. the experiment was conducted at the agronomy research field of bangladesh agricultural research institute (bari), joydebpur, gazipur and regional agricultural research station, burirhat, rangpur during rabi season of 2013-14 and 2014-15. six treatments viz., simultaneous sowing of potato and sweet corn, sweet corn sown at 10 days after potato planting (dapp), sweet corn sown at 20 dapp, sweet corn sown at 30 dapp, sole potato and sole sweet corn were tested. the experiment was laid out in randomized complete block design with three replications. the unit plot size was 6.0 m × 5.0 m. the potato var. bari alu-7 (diamant) and sweet corn var. bari sweet corn-1 was used. potato in all the treatments was planted on 24 november 2013 and 17 november 2014 at joydebpur and on 20 november 2013 and 17 november 2014 at burirhat. sweet corn was sown according to the treatments. sole sweet corn was sown on the date of potato planting. potato was planted with 60 cm × 25 cm spacing in sole and 75 cm × 20 cm spacing in intercrop situation. sweet corn was sown with 75 cm × 20 cm spacing both in sole and intercrop situation. in intercrop treatments, one row of sweet corn was accommodated in between two rows of potato. for sole potato and sole sweet corn fertilizers were applied @ n180 p40 k180 s20 zn6 b1.2 and n160 p50 k100 s40 zn4 b2 kg ha-1, respectively (frg, 2012). for intercrop fertilizers were applied @ n320 p73 k170 s50 zn6 b2 kg ha-1. the source of n, p, k, s, zn and b was urea, tsp, mop, gypsum, zinc sulphate and boric acid, respectively. in case of sole potato, half amount of urea and mop and the whole amount of tsp, gypsum, zinc sulphate and boric acid were applied at the time of final land preparation. remaining 1/2 amount of urea and mop were applied at 30 days after sowing (das). for sole sweet corn, one-third of urea and whole amount of other fertilizers were applied at the time of final land preparation. remaining 2/3 amount of urea was applied in two equal splits as side dressing at 30 and 55 days after sowing (das). in case of intercrop, onethird urea and of all other fertilizers were applied as basal. one-third urea and rest of all other fertilizers were side dressed at 30 dap of potato and rest of urea was side dressed just after potato harvest followed by irrigation. irrigation and other intercultural operations were done as and when required. fungicide (dithane m-45) was sprayed at every 10-day intervals beginning from 25 to 70 dap for preventing disease of potato. all data were taken at harvesting. potato was harvested at 90 dap at both the location yearwise. sweet corn was harvested at 115-120 das in both locations. light availability was measured by par ceptometer (model – lp-80, accu par, decagon, usa). economic analysis was also done. potato equivalent yield was computed based on prevailing market price of both the crops by the following formula of bandyopadhyay (1984) as given below: potato equivalent yield = yip + (yisc  psc)/pp where, yip = yield of intercrop potato, yisc = yield of intercrop sweet corn, pp = market price of potato and psc = market price of sweet corn. results and discussion light availability irrespective of treatments, availability of light on potato canopy was almost 100% at earlier growth stage of potato i.e. 30 dapp and it decreased with the increase of shade produced by sweet corn. among treatments, light availability on potato canopy was more in the treatment where sweet corn was sown 30 dapp throughout growing period and minimum in treatment where potato and sweet corn was planted on same date. it indicated that light availability on potato canopy throughout the crop period, increased with the delay sowing of sweet corn compared to simultaneous sowing (fig.1). 17 effect of sowing date of sweet corn on potato + sweet corn intercropping system fig. 1. light availability on potato plant in potato + sweet corn intercropping at joydebpur effect on tuber yield and yield components of potato yield and yield components of potato were significantly affected in potato/sweet corn intercropping systems in both locations (table 1 & 2). the highest number of tubers/hill of potato was observed where sweet corn sown at 30 dapp followed by sole potato and sweet corn sown 20 dapp and the lowest in potato and sweet corn sown simultaneously at joydebpur location. similar trend was observed in tuber weight/hill. but at rangpur, significantly the highest number of tuber/hill and weight of tuber hill-1 were recorded in sole potato. these parameters were reduced with earlier planting of sweet corn in between two potato rows in both locations and years. the lower values of those parameters might be due to the shading effect of sweet corn plants as well as inter specific competition. at joydebpur, the results indicated that potato yield was higher than sole potato when sweet corn sown 30 days after potato planting followed by sole potato in both the years (25.00 t ha-1 in 2013-14 and 26.31 t ha-1 in 2014-15). it might be for lower temperature due to shading during later growth stage of potato which favoured tuber bulging for longer period and ultimately increased tuber yield when sweet corn sown 30 days after potato planting. kuruppuarachchi (1990) also observed similar results in potato + maize intercropping. he reported that higher tuber yield was recorded where corn sown 14 days after potato planting. on the contrary, the highest tuber yield (28.84 t ha-1 and 29.25 t ha-1 in 2013-14 and 2014-15, respectively) was observed in sole potato at rangpur. tuber yield in sole potato was statistically identical with the treatment where sweet corn sown 30 days after potato planting in 2014-15. corn sown simultaneously with potato gave the lowest tuber yield was observed in both locations. it might be due to less availability of light on potato canopy during tuber bulging period which reduced tuber yield (fig.1). tuber yield in different treatments were attributed to the cumulative effect of yield components viz., number of stems/hill, number of tuber hill-1 and tuber weight hill-1. table 1. yield and yield components of potato in potato + sweet corn intercropping under different sowing date of sweet corn in rabi season at joydebpur tubers hill-1 (no.) tuber wt. hil-1l (g) tuber yield (t ha-1) yield increase/decrease over sole potato (%) sweet corn planting (days after potato) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 same time 7.0 8.5 363.12 409.20 19.32 20.01 21.8 21.3 18 begum et al. 10 days 7.1 9.3 375.12 437.87 21.36 23.12 13.6 9.1 20 days 7.8 9.6 416.17 464.53 23.71 24.58 4.1 3.4 30 days 9.0 11.3 440.10 538.00 25.00 26.31 + 1.1 + 3.4 sole potato 8.5 10.8 431.15 492.40 24.72 25.44 lsd(0.05) 1.34 0.80 38.82 38.44 3.01 3.10 cv (%) 6.19 2.97 3.50 3.00 4.81 4.74 (-) indicates yield decrease, (+) indicates yield increase table 2. yield and yield components of potato in potato + sweet corn intercropping under different sowing date of sweet corn in rabi season at rangpur tuber hill-1 (no) tuber hill-1 (g) tuber yield (t ha-1) yield increase/decrease over sole potato (%) sweet corn planting (days after potato) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 same time 7.59 8.01 336.79 338.24 21.12 22.45 26.8 23.2 10 days 8.48 8.87 376.61 381.15 24.21 23.72 16.0 18.9 20 days 8.52 9.27 423.46 432.43 26.43 26.96 8.4 7.8 30 days 8.71 9.51 432.72 451.40 26.56 27.15 7.9 3.1 sole potato 8.77 10.17 460.18 469.82 28.84 29.25 lsd (0.05) 0.69 0.85 23.27 29.35 2.06 2.48 cv (%) 4.51 4.94 3.15 3.76 4.47 5.10 (-) indicates yield decrease, (+) indicates yield increase effect on yield and yield components of sweet corn number of cobs m-2, weight of single cob with husk, yield of cob with husk of sweet corn and green fodder yields were influenced significantly under different intercropping systems (table 3 & 4). the number of cobs per unit area in all the treatments was similar except sweet corn sown 30 days after potato planting in both locations. the lowest number of cobs m-2 (5.57 in 2013-14 and 5.50 in 201415 at joydebpur and at rangpur 5.49 in 2013-14 and 5.51 in 2014-15) in sweet corn sown 30 days after potato planting was found might be due to lower number of maize population per unit area. in this treatment, germination of sweet corn was affected and seedlings growth was hampered due to heavy shading produced by potato canopy that resulted poor growth and less number of cobs m-2. similar result was reported by zaag and demagante (1990). the highest single cob weight was observed in sole corn in both year and the locations which might be due to wider spacing which helped to provide more light and nutrients to crop plants. the maximum cob yield (with husk) was found in sole sweet corn in both locations (17.21 t ha-1 in 2013-14 and 17.10 t ha-1 in 2014-15 at joydebpur and at rangpur, 15.08 t ha-1 in 2013-14 and 14.76 t ha-1 in 2014-15) and it was statistically similar with potato + sweet corn sown simultaneously at joydebpur. the lowest cob yield in sweet corn sown 30 days after potato planting in both locations might be due to cumulative effect of lower yield contributing characters. similar trend was observed in case of green fodder yield. yield of cobs gradually decreased with delay in sowing time of sweet corn owing to shorter growth duration and higher temperature at later growth stages. islam (2002) also reported similar results in maize + bush bean intercropping system. ifenkwe and odurukwe (1990) reported that potato yields increased with delay sowing in association with maize while maize yields decreased as its sowing date was delayed. table 3. yield and yield components of sweet corn in potato+ sweet corn intercropping under different sowing dates of sweet corn in rabi season at joydebpur sweet corn planting (days after cobs m-2 (no.) single cob weight with husk (g) yield of cob with husk (t ha-1) green fodder yield (t ha-1) 19 effect of sowing date of sweet corn on potato + sweet corn intercropping system potato) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 same time 6.66 6.66 303.1 295.0 16.76 16.67 29.63 29.50 10 days 6.59 6.60 268.0 272.0 15.47 15.50 27.98 28.33 20 days 6.54 6.59 257.0 261.0 14.75 14.70 25.65 25.95 30 days 5.57 5.50 238.9 251.0 11.99 11.50 21.33 20.10 sole sweet corn 6.66 6.66 349.8 310.0 17.21 17.10 32.10 31.50 lsd(0.05) 0.48 0.71 73.12 24.24 2.71 1.50 5.35 3.32 cv (%) 2.77 4.04 9.42 3.19 6.49 3.63 7.14 4.47 table 4. yield and yield components of sweet corn in potato+ sweet corn intercropping under different sowing dates of sweet corn in rabi season at rangpur cobs m-2 (no) single cob weight (g) yield of cob with husk (t ha-1) green fodder yield (t ha-1) sweet corn planting (days after potato) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 same time 6.65 6.66 205.17 201.97 13.55 13.42 27.67 28.02 10 days 6.61 6.62 202.51 197.88 13.37 13.25 26.53 26.83 20 days 6.58 6.60 195.56 196.12 13.22 12.97 24.18 24.45 30 days 5.49 5.51 177.38 171.45 11.36 11.18 18.30 18.60 sole sweet corn 6.65 6.67 248.29 239.89 15.08 14.76 29.70 30.00 lsd (0.05) 0.69 0.65 15.22 23.50 0.96 1.42 4.99 6.10 cv (%) 3.96 3.72 4.06 6.19 3.97 7.77 10.49 12.60 intercrop efficiency potato equivalent yield (pey) and land equivalent ratio (ler) of potato + sweet corn intercropping systems are presented in table 5. pey of all the intercropping was higher than sole cropping indicating higher productivity of intercropping than sole cropping. the highest pey (joydebpur: 41.41 t ha-1 in 2013-14, 42.22 t ha-1in 2014-15 and rangpur: 42.29 t ha-1in 2013-14, 42.52 t ha-1 in 2014-15) and ler (joydebpur: 1.82 in 2013-14, 1.83 in 2014-15 and rangpur: 1.80 in both the year) were observed in sweet corn sown 20 days after potato planting. cimmyt in bangladesh (2005 and 2006) reported that intercropping maize at 20-35 days after the planting of potato can bring very high profit, providing 20-21 tha-1maize equivalent yield within five months. hybrid maize sown after 2025 days of potato planting gave 31.50-32.80 t ha-1 potato equivalent yield (islam et al., 2010). begum (2015) found 25.78-31.30 t ha-1 also when hybrid maize intercropped with potato at 20-30 days after potato planting. economic performance the economic performance of intercropping system is presented in table 6. the highest gross return at joydebpur tk. 431050 ha-1 and at rangpur tk. 436248 ha-1, gross margin at joydebpur tk. 286805 ha-1 and at rangpur tk. 271985 ha-1 and benefit cost ratio at joydebpur 2.99 and at rangpur 3.01 were observed average over two years in sweet corn sown 20 days after potato planting. islam et al. (2010) reported that hybrid maize sown after 20-25 days of potato planting gave 4.00-4.23 benefit cost ratio. it was also observed that the highest gross return tk. 258800-313000 ha-1, gross margin tk. 146478-200678 ha-1 and benefit cost ratio 2.30-2.79. table 5. potato equivalent yield and land equivalent ratio of potato + sweet corn intercropping under different sowing dates of sweet corn in rabi season at joydebpur and rangpur joydebpur rangpursweet corn planting (days after potato equivalent yield (t ha-1) ler potato equivalent yield (t ha-1) ler 20 begum et al. potato) 201314 201415 201314 201415 2013-14 2014-15 201314 2014-15 same time 39.43 40.01 1.76 1.76 37.38 38.55 1.63 1.68 10 days 39.92 41.72 1.76 1.82 40.25 39.62 1.73 1.71 20 days 41.41 42.22 1.82 1.83 42.29 42.52 1.80 1.80 30 days 39.39 40.11 1.71 1.71 40.19 40.57 1.67 1.69 sole potato 24.71 25.44 1.00 1.00 28.84 29.15 1.00 1.00 sole sweet corn 20.65 20.52 1.00 1.00 18.10 17.71 1.00 1.00 market price (tk kg-1): potato = 10, sweet corn = 12, fodder = 0.50 table 6. economic analysis of potato + sweet corn intercropping under different sowing dates of sweet corn in rabi season at joydebpur and rangpur average over the years gross return (tk ha-1) total cost of production (tk ha-1) gross margin (tk ha-1) bcrsweet corn planting (days after potato) joydebpur rangpur joydebpur rangpur joydebpur rangpur joydebpur rangpur same time 411993 393613 144245 145150 267748 228458 2.86 2.71 10 days 422288 412710 144245 145150 278043 247853 2.93 2.84 20 days 431050 436248 144245 145150 286805 271985 2.99 3.01 30 days 407848 413015 144245 145150 263603 249428 2.83 2.85 sole potato 250750 289950 128266 127250 122484 162700 1.96 2.28 sole sweet corn 213885 193965 104279 100250 109606 105690 2.05 1.94 market price (tk kg-1): potato = 10, sweet corn = 12, fodder = 0.50 conclusion two years results revealed that sowing of sweet corn 20 days after potato planting might be agronomically feasible and economically profitable for sweet corn and potato intercropping system as compared to sole sweet corn in both the location in addition fodder yield could be possible from sweet corn plant to mitigate the livestock feed to some extent. reference bandyopadhyay, s. n. 1984. nitrogen and water relations in grain sorghum legume intercropping systems, phd thesis, indian agril. res. inst., new delhi. begum, a. a. 2015: performance of potato maize intercropping as affected by sowing date, row arrangement and fertilizer management, phd thesis, dept. agron., bangladesh agril. univ., mymensingh, bangladesh. pp. 79-82. chrispher, r., r. dowswell, l. paliwal and p. c. ronald 1996. maize in the third world. steven a. breth, series editor. westview press inc.colrado usa. p. 23. cimmyt office in bangladesh 2005. maize whole family training. in: food security in bangladesh: improving wheat, maize and papaya production and impacts of arsenic contamination. project annual report for 2004-2005. pp. 45-66. 21 effect of sowing date of sweet corn on potato + sweet corn intercropping system cimmyt office in bangladesh 2006. maize whole family training. in: food security in bangladesh: improving wheat, maize and papaya production and impacts of arsenic contamination. project annual report for 2005-2006. pp. 31-44. fao 2008. food and agriculture organization of the united nations, production 2007-2008 year book of the potato, fao, rome, italy. pp. 85-100. frg 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), new airport road, farmgate, dhaka 1215. pp 92-110. ifenkwe, o. p. and s. o. odurukwe 1990. potato/maize intercropping in the jos plateau of nigeria. field crops res. 25: 73-82. islam, m. n. 2002. competitive interference and productivity in maize-bushbean intercropping system, phd thesis, dept. agron., bangabandhu sheikh mujibur rahman agril. univ., gazipur, bangladesh. islam, m. n., f. ahmed and m. a. hossain. 2010. intercropping technologies 2000-2009. agronomy division, bangladesh agricultural research institute, joydebpur, gazipur 1701, bangladesh. pp. 13-15. kuruppuarachchi, d. s. p. 1990. intercropped potato (solanum spp.). effect of shade on growth and tuber yield in the northwestern recosol belt of sri lanka. field crops res. 25: 61-72. santalla, m., a. p. rodino, p. a. casquero and a. m. de ron 2001. interactions of bush bean intercropped with field and sweet maize. european j. agron. 15: 185-196. santalla, m., p. a. casquero and a. m. de ron 1999. yield and yield components from intercropping improved bush bean cultivars with maize. agron. crop sci. 183: 263-269. zaag, v. p. and a. l. demagante 1990. potato (solanum spp.) in an isohyperthermic environment. v. intercropping with maize. field crops res. 25: 157-170. yield performance of lentil influenced by genotype and inoculant interaction bangladesh agron. j. 2014, 17(1): 41-46 performance of lentil varities as influenced by different rhizobium innoculations m. a. haque1, p. bala2 and a. k. azad2 1lecturer, lakhpur shimulia college, narosindhi 2ph.d. fellow, hajee mohammad danesh science & technology university, dinajpur. corresponding author: kbdpronay@yahoo.com key words: yield, inoculation, lentil abstract a field experiment was conducted at the farm of bangladesh agricultural university, mymensingh during november 2009 to march 2010 to study the response of three lentil varieties (viz., bari masur-1, bari masur-2 and bari masur-3) to rhizobium inoculations to yield. there were three rhizobium inoculants (rhizobium strain bina l4, rhizobium strain tal 640, and mixed culture) with uninoculated control and urea @ 50 kg ha-1. phosphorus and potassium @ 26 kg p ha-1from tsp and 33 kg k ha-1 from mp were used as basal. it was observed that rhizobium inoculation alone increased plant height, grain yield and crop residues yield of plant significantly compared to uninoculated control. local inoculants bina l4 performed better than the exotic culture tal 640 in respect of yield. 50 kg urea ha-1 also recorded better results than control but not superior to any of the inoculation treatments. the highest seed (1,565 kg ha-1) and crop residue yields (3,303 kg ha-1) were recorded from the lentil variety barimasur-3 inoculated with mixed culture. introduction lentil (lens culinaris medik) is one of the most important pulse crops grown in bangladesh. it belongs to the sub-family papilionaceae under the family leguminosae. in bangladesh, it is popularly known as masur. lentil grain contains 25% protein, 0.7% fat, and 59% carbohydrate (afzal et al., 1999). the lentil crop covers 33.33 percent of the total area of pulse in the country (bbs, 2012). total production of lentil in bangladesh, during 2010-2011 was 228568 tons from an area of 180574 hectare with an average yield of 1.2657 t ha-1 (bbs, 2012). pulses are considered as the poor man’s meat as they are the cheapest source of protein for the underprivileged people who cannot afford to buy animal proteins (gowda and kaul, 1982). the stover of the plants together with husk popularly known as bhushi is highly protein concentrated feed for cattle, horse, pig and sheep (tomar et al., 2000). lentil being a legume crop can fix atmospheric nitrogen through root nodules by rhizobium bacteria, which may reduce the pressure of nitrogenous fertilizer application to the crop. it is evident that pulse included in the cropping pattern helped to increase the organic matter in the soil (islam, 1988). seed inoculation with appropriate rhizobium sp is recommended to improve legume growth. they can reduce nitrogenous fertilizer use and protect environment. response to rhizobium inoculation to lentil depends on the soil type, crop cultivars and effectiveness of rhizobium strains. research work on contribution of rhizobium inoculation on growth and yield of lentil is, however, scanty in this country. the selection of strain of rhizobia particularly adapted to specific host plant is important. judicious matching of rhizobium stains with host plants and prudent use of large viable inocula prepared with these organisms is the only way to attain maximum nitrogen fixation and yields of leguminous crops. keeping these in view, the investigation was undertaken to evaluate the effectiveness of three rhizobium inoculants to lentil varieties in respect of yield. materials and methods 42 haque el al. a field experiment was conducted during the winter (rabi) seasons of 2009 -2010 at the farm of the department of soil science, bangladesh agricultural university, mymensingh. the land was situated to the north east side of the farm and situated at latitude of 24.75 ºn and a longitude of 90.50º e. the initial soil sample of the experimental field was collected and analyzed following standard procedures in the laboratory and presented in table 1. table 1. initial soil nutrient status of the experimental field constituents ph oc (%) om (%) total n (%) available p (ppm) exchangeable k (me 100 g-1 soil) ca mg cec experimental field 6.7 1.085 1.875 0.089 11.95 0.12 0.12 3.95 18.50 critical level 2.0 0.1 0.8 14 0.2 14 3.1 0.12 the experiment was laid out in split-plot design having four replications with 3 lentil varieties in main plots and 5 inoculation (no inoculation, bina l4 as a local rhizobium strain, tal 640 as an exotic rhizobium strain, bina l4 and tal 640 as mixed culture and urea at the rate of 50 kg/ha in sub plots the recommended dose of 26 kg p, 33 kg k was applied as basal. the land was prepared by ploughing and crossploughing with the country plough followed by laddering uniformly. fresh seeds of lentil were dipped in the respective culture broth of 5 days growth for two and half an hours. the seeds were dried in shade. the inoculated seeds of three inoculation treatments were randomly placed in the 5 unit plots of each main plot with spacing of 30 cm using 50 kg seed ha-1 sowing at 22 november, 2009 and harvested at 12 march, 2010. the harvested area of each plot was 4m x 2.5m. the crop was raised following recommended agronomic practices. data on plant height from each plot 5 randomly selected plants were carefully measured and their mean values were determined. the yields were taken plot-wise by harvesting of each plot and then it was converted to hectare basis. the collected data were analyzed statistically using the analysis of variance technique with the help of computer package mstat and mean differences were adjudged by duncan's multiple ranged test (dmrt) (gomez and gomez, 1984). results and discussion plant height the effect of inoculation on plant height (cm), grain yield (kg ha-1), crop residues yield (kg ha-1) and percent yield increase over control are presented in table 2 and table 3. effect of rhizobium inoculation the results showed that the mixedculture gave the highest plant height (11.49 cm) at 40 days of sowing, the percent increase over uninoculated control being 8.8. at 60 days of sowing binal 4 gave highest plants height (18.03 cm) and percent increases over control being 16. at 80 days of sowing recorded the highest plant height (28.32 cm), percent increase over control being 15.26. the maximum plant height (34.30 cm) was produced by mixed culture at 95 days of sowing, which was statistically superior to other treatments. gwal et al. (1995) reported that the rhizobium inoculants when applied resulted in the tallest plants and more branches/plant than the control. similar results were obtained by maurya and sanoria (1986) in chickpea. varietal response at vegetative stage (40 days of sowing), the maximum plant height was produced by the variety bari masur-3 (11.12 cm) followed by barimasur-1 (11.09 cm) and bari masur-2 (10.93 cm). variety bari masur-3 gave tallest plant (16.92 cm) at 60 days of sowing, which was statistically superior to all other varieties. at 80 days of sowing, variety bari masur-2 gave the maximum plant height (27.54 cm) which was statistically similar with bari masur-3 (27.40 cm) but significantly higher than bari masur1 (fig. 2). variety bari masur-3 gave the maximum plant height (33.26 cm) at 95 days of sowing which was statistically similar with bari masur-2 (32.83 cm) but significantly higher than bari masur-1 (31.23 cm) the above results are in agreement with the findings of sattar et al. (1995) who found that 43 rhizobium innoculation in lentil seed inoculation with bradyrhizobium increased plant height of five chickpea cultivars. similar results were obtained by fakir et al. (1988) in pigeonpea. table 2. effect of rhizobium inoculation and variety on seed and hay yield of lentil factor seed yield (kg ha-1) crop residue (kg ha-1) yield increase over control (%) inoculant no inoculated 894d 1,870c rhizobium strain bina l 4 1,163b 2,537b 35.67 rhizobium strain tal 640 1,114b 2,520b 34.76 mixed inoculation 1,309a 2,965a 58.56 urea @50 kg n/ha(u50) 960c 1,915c 2.41 ** ** variety barimasur-1 944c 2,199b barimasur-2 1,044b 2,404ab barimasur-3 1,276a 2,482a ** * in a column, figures having common letter(s) do not differ significantly and those having different letter(s) differ significantly at 5 %(*) and 1% (**) level of significance. table 3. the interaction effect of rhizobium inoculation and variety on plant height, grain yield and hay yield of lentil rhizobium× variety interaction plant height (cm) seed yield (kg ha-1) crop residue (kg ha-1) 40 days 60 days 80 days** 95 days * * v1r0 10.63 15.55 20.95h 30.95 799i 1,784e v1rl 11.25 17.50 26.50fg 30.00 1,004e 2,334d v1re 11.10 16.70 25.95g 30.05 979fg 2,309d v1rm 11.45 16.40 27.15c-f 33.90 1,118de 2,722bc v1u50 11.00 15.75 26.10g 31.25 821hi 845e v2r0 10.07 15.35 26.65cfg 31.00 858hi 1,954e v2rl 11.10 18.00 27.75bcd 33.90 1,107de 2,600c v2re 11.18 16.55 27.85bcd 33.20 1,106de 2,600c v2rm 11.45 16.80 28.70ab 34.00 1,243c 2,869b v2u50 10.85 15.45 26.75efg 32.75 906gh 1,995e v3r0 10.98 15.60 26.10g 31.80 1,023ef 1,872e v3rl 11.45 18.60 28.00bc 33.00 1,379b 2,675bc v3re 11.25 17.05 27.55cde 33.55 1,256c 2,651bc v3rm 11.57 17.30 29.10a 35.00 1,565a 3,303a v3u50 10.35 16.05 26.25fg 32.95 1,154d 1,906e cv (%) 5.80 2.79 4.18 5.65 6.35 in a column, figures having common letter(s) do not differ significantly and those having different letter(s) differ significantly at 5 %(*) and 1% (*) level of significance. r0= uninoculated v1= bari masur-1 rl= rhizobium strain bina l4 v2 =bari masur-2 re= rhizobium strain tal 640 v3 =bari masur-3 rm= mixed culture of bina l4 and tal 640 u50 = urea @ 50 kg n ha-1 44 haque el al. 0 10 20 30 40 pl an t h ei gh t (c m ) no inoculated binal 4 tal640 mixed u50 inoculant plant height 40das 60das 80das 95das figure 1. effect of rhizobium inoculation (upper) on plant height of lentil plant height 0 5 10 15 20 25 30 35 40 60 80 95 days after sowing pl an t h ei gh t( cm ) bari masur-1 bari masur-2 bari masur-3 figure 2. effect of variety on plant height of lentil interaction of rhizobium and variety at 40 days of sowing the highest plant height (11.57 cm) was obtained by the treatment bari masur-3 x mixed culture (v3rm), followed by interaction treatment v3rl, v3re, v2rm, v2re, v2rl v1rm, v1rl, v1re, v1 u50 (bari masur-1 × urea @ 50 kg ha-1) and v3 r0 (barimasur-3 × uninoculated control) which was statistically similar (table 1). the highest plant height (18.60 cm) was produced by the interaction of v3rl at 60 days of sowing. the association v3rm, recorded the highest plant height (29.10 cm) at 80 days of sowing which was statistically superior to all other interaction treatments. the association v3rm, recorded the highest plant height (35.00 cm) at 95 days of sowing which was statistically superior to all other interaction treatments. the above results are supported with the findings of some investigators. lee and yun (1989) reported on soybean when inoculated with rhizobium stains increased plant height over uninoculated control. similar results were obtained by sattar and ahmed (1995) in mungbean. seed yield 45 rhizobium innoculation in lentil significant positive effect of rhizobium inoculation on seed yield of lentil over noninoculated control was observed (table 2 & table 3). the mixed culture inoculation produced the highest seed yield (1,309 kg ha-1), which was statistically superior to all other treatments, the percent increases (46%) over uninoculated control.. bremer et al. (1990) reported that the rhizobium increased seed yield of lentil by up 135%. namedo et al. (1996) also observed that inoculation increased lentil seed yield by 17.5-23.2% compared with no inoculation. barimasur-3 recorded the highest grain yield (1,276 kg ha-1), which was statistically superior to both varieties. the highest grain yield (1,565 kg ha-1) was recorded from the combination of bari masur-3 with mixed inoculation (v3rm0), which was statistically superior to all other treatments(table 3). similar results were observed by dziamba and miroslaw (1994) in lentil. crop residue the highest crop residue (2,965 kg ha-1) was recorded in mixed culture, which was significantly superior to all other treatments. it was higher than uninoculated control by 59%. the above results indicated that there was significant beneficial effect of inoculation on crop residue compared to uninoculated control. similar results were also obtained by podder et al. (1989) in lentil. the highest crop residue (2,482 kg ha1) was obtained by the variety bari masur-3, which was statistically superior to bari masur-1 (2,199 kg ha-1) but similar to bari masur-2 (2,404 kg ha-1). similar results were found by islam and afandi (1980) in lentil. the interaction of v3rm recorded the highest crop residue (3,303 kg ha-1), which was significantly superior to all other treatments. the above results are similar with that of bhuiya et al. (1986). correlation the relationship between total number of nodules at 60 days of sowing and grain yield has been found out. the correlation coefficient (r = 0.6425) was found significant at 1% level of probability. the relation was positive i.e. increase in nodule number results in an increase in the seed yield of lentil. the statistical relationship between total number of nodules at 60 days and crop residues has been calculated and found positive the correlation coefficient (r = 0.858) was highly significant. the statistical relationship between nodule dry weight at 60 days and seed yield has been found positively correlated. the correlation coefficient (r = 0.665) was highly significant. the statistical relationship between total number of nodules at 60 days and crop residues has been found positively correlated. the correlation coefficient (r = 0.858) was highly significant. the statistical relationship b nodule dry weight at 60 days and crop residues has been positively correlated. the correlation coefficient (r = 0.900) was highly significant. the statistical relationship between grain yield and hay yield has been found positively correlated. the correlation coefficient (r = 0.775) was highly significant. conclusion the present investigation suggested that lentil genotype bari masur-3 produced highest seed yield and crop residue. rhizobium strain bina l4 and tal 640 were effective items in term of yield. a significant and positive correlation was observed between nodule number and nodule weight, crop residues and seed yield; nodule weight, crop residue and seed yield. further study is necessary to draw a definite conclusion. references afzal, m. a., m. a. bakr and m. l. rahman. 1999. lentil cultivation in bangladesh. lentil, blackgram and mungbean development pilot project, pulses research station, bari, gazipur-1701. 46 haque el al. bbs. 2012. yearbook of agricultural statistics of bangladesh. bangladesh bureau of statistics, ministry of planning, government of the people’s republic of bangladesh, dhaka. bhuiya, z. h., m. r. islam, m. j. uddin and m. s. hoque.1986. performance of some rhizobium inoculations on blackgram (vigna mungo). bangladesh j. agric. 11(4): 55-63. bremer, e., c. kessel, l. nelson, r. j. rennie, d. a. rennie and c. van-kessel. 1990. selection of rhizobium leguminosarum strains for lentil (lens culinaris) under growth room and field conditions. plant soil. 121(1): 47-56. dziamba, s. and h. microslaw.1994. effect of inoculating lentil seeds with rhizobium strains on yield. biuletyn instytutu hodowli-i aklimatyzacji roslin. no. 189, 85-90:11. fakir, m. s. a., a. a. a. mushi and s. m. m. alam. 1998. effects of rhizobium inoculation, nitrogen and phosphorus on yield contributing characters of soybean. bangladesh j. agril. sci. 15(2): 211-215. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agric. res. 2nd edn. john willey and sons. new york. pp.207-215. gowda, c. l. l. and a. k. kaul. 1982. pulses in bangladesh, bari publication. 6 (1): 27-29. gwal, h. b., r. j. tiwari and d. k. gupta. 1995. fertilizer management of lentil under rainfed conditions in madhya prodesh. lens newsl. 22(1-2): 11-12. islam, r. and f. afandi. 1980. response of lentil cultivars to of rhizobium inoculation and nitrogen fertilization. lens. 7: 50-51. islam, m. s. 1988. nutrient status of bangladesh soils. annual report for 1988. bangladesh agril. res. inst., gazipur, bangladesh. pp.82-85. lee, h. s. and s. h. yun. 1989. studies on the response of rhizobium inoculation and nitrogen concentration on growth and yield of soybean cultivars. korean j. crop sci. 34(4): 400-407. maurya, b. r. and c. l. sanoria. 1986. beneficial effects of coinoculating chickpea seed with rhizobium , azotobacter and pseudomonas . indian j. agric. sci. 56(6): 463-466. namdeo, s. l., s. c. gupta and r. k. joshi. 1996. influence of rhizobial inoculation on nodulation and yield of lentil genotypes under rain fed conditions. lens newsletter. 23(1& 2): 24-26. podder, a. k., m. a. sattar and g. marshed. 1989. performance studies of some isolated native rhizobial inocula on the production and nodulation of lentil with or without nitrogen fertilizer. proc. 6 th natl. bot. conf., jan. 18-19. abs. no. 43, p.23. podder, a. k. 1994. performance of single and mixed rhizobial inoculafor nodulation and growth of lentil. lens newsl. 21 (1): 39-40. sattar m. a., m. a. quader and s. k. a. danso. 1995. nodulation, nitrogen fixation and yield of chickpea as influenced by host cultivar and bradyrhizobium stain differences. soil biol. biochem. 27 (4/5): 725727. sattar, m. a. and s. u. ahmed. 1995. response of mungbean (vigna radiata l. wilczek) to inoculation with bradyrhizobium as affected by phosphorus levels. proc. intl. cong. comm. iv. pp.419-423. tomar, s. k., p. tripathi and a. l. rajput. 2000. effect of genotype, seeding method and diammonium phosphate on yield and protein and nutrient uptake of lentil (lens culinaris l. medik). indian j. agron. 45 (1): 148-152. table: effect of nitrogen management in some drought tolerant rice varieties in aman season bangladesh agron. j. 2015, 18(2): 9-14 response of nerica rice to nitrogen fertilization r. shultana1*, m. a. a. mamun2, l. naher1, m. k. a. bhuiyan1 and a. j. mridha1 1agronomy division, bangladesh rice research institute, gazipur-1701 2department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706. *corresponding author: rakiba_83@yahoo.com key words: nerica, nitrogen fertilizer, nitrogen use efficiency, yield abstract an experiment was conducted during t. aman season, 2014 at the agronomy research field, bangladesh rice research institute, gazipur to determine the optimum rate of nitrogen fertilizer for higher yield in nerica rice. the experiment comprised of three rice varieties viz. nerica1, nerica10 and brri dhan57; and five nitrogen levels viz. 0, 23, 46, 69 and 92 kg ha-1. the rice var. brri dhan57 with 69 and 92 kg n ha-1 produced significantly identical with higher panicles m-2. but nerica1 and nerica10 produced higher number of panicles with 46 and 69 kg n ha-1, respectively. however, brri dhan57 with 46 kg n ha-1 produced highest grains panicle-1 but nerica1 and nerica10 produced higher number of grains panicle-1 with 23 kg n ha-1. the highest percentage of sterility was recorded in nerica10 with 69 kg n ha-1. the regression analysis gave the optimum dose of nitrogen for nerica1, nerica10 and brri dhan57 which were 69.25, 74.25 and 85.75 kg n ha-1, respectively. introduction rice (oryza sativa l.) is the most extensively cultivated cereal crop in bangladesh, which covers about 74% of the total cropped area (bbs, 2013). in respect of area and production of rice, bangladesh ranks fourth following china, india and indonesia (fao, 2014). the area, production and yield of rice in the country are 11.42 million ha, 33.85 million tons and 2.96 t ha-1, respectively (bbs, 2013). previous studies revealed that proper use of fertilizer can increase the yield and improve the quality of rice significantly (awan et al., 2003; ahmed et al., 2005; oikeh et al., 2008). nerica1 and nerica10 is a new rice variety in bangladesh which is short duration as well as drought tolerant. development of proper fertilizer management strategy is one of the most important agronomic practices for its successful adoption in bangladesh, especially in the drought prone areas. among the agronomic practices, management of nitrogenous fertilizer plays the most important role for augmenting the rice yield. okeleye and kehinde (2009) reported that application of 30 kg n in nerica1 enhanced the number of tillers by 10% only at 21 days after transplanting (dat) compared to zero-n. these results were also supported by adigbo and okeleye (2006) and oikeh et al. (2008). therefore, judicious dose of nitrogen fertilizer in aman rice cv. nerica1 and nerica10 is necessary under bangladesh condition. the present study was therefore conducted to determine the optimum rate of nitrogen fertilizer for getting higher yield in nerica1 and nerica10 varieties and compare with brridhan 57. materials and method a field experiment was conducted during t. aman season 2014 at the agronomy research field, bangladesh rice research institute, gazipur. the experiment was laid out in a randomized complete block design (rcbd) with three replications. plot size was 4m  3m. the experiment comprised of 10 shultana et al. three rice varieties viz. nerica1, nerica10 and brri dhan57; and five nitrogen levels viz. 0, 23, 46, 69 and 92 kg ha-1. triple super phosphates, muriate of potash, gypsum and zinc sulphate were applied at 70-60-50-5 kg ha-1. the whole dose of triple superphosphate, muriate of potash, gypsum, zinc sulphate and one third of nitrogen were applied at the time of sowing. the remaining doses of nitrogen were applied in two splits at tillering and panicle initiation. data on yield and yield component were recorded at harvest and mean differences were depicted by multiple comparison test (gomez and gomez, 1984) using the statistical program mstat-c (russell, 1986). nitrogen use efficiency the efficiency of applied n was assessed using the following indices (dobermann and fairhurst, 2000). a. agronomic efficiency (ae) agronomic efficiency is the kg grain yield increase kg-1 n applied. often used as nitrogen use efficiency (nue). aen = (gy+ n – gy0 n) / fn where, aen = agronomic efficiency of n; gy+ n = grain yield due to addition of fn; gy0 n = grain yield without addition of n; fn = amount of n applied (kg ha-1). b. partial factor productivity (pfp) partial factor productivity is the kg grain yield kg-1 n applied. pfpn = gy+ n / fn where, pfpn = partial factor productivity of n; gy+ n = grain yield due to addition of fn; fn = amount of n applied (kg ha-1). results and discussion yield components among the yield components, panicles m-2 and sterility (%) showed significant effect with different rates of fertilizer. brri dhan57 with nitrogen rate 69 and 92 kg ha-1 produced panicles m-2 which was 202 and 203 respectively significantly higher and statistically similar. the highest number of panicles m-2 was found from nerica1 and nerica10 with 46 and 69 kg n ha-1, respectively. nitrogen rates did not show any significant effect on grains panicle-1. however, brri dhan57 with 46kg n produced highest grains panicle-1 (151). besides nerica1 and nerica10 with 23kg n/ha produced 68 and 79 grains/panicles, respectively. increase in grain yield for application of n was mainly due to improvement in yield components i.e. number of effective tillers and grains panicle-1. thousand grain weight did not significantly influenced by n level in cultivated rice varieties. however, numerically maximum 1000-grain weight was recorded from nerica1 with 69 kg n ha-1. the highest sterility percent was recorded in nerica10 with 69 kg n ha-1 (43.40%). in contrary the lowest sterility percent (22.37%) from brri dhan57 with 0 kg n ha-1 (table 1). table 1. effect of nitrogen fertilizer on yield components of three rice varieties n added (kg ha-1) panicles m-2 grains panicle-1 1000grain weight (g) sterility (%) nerica1 0 121g 52 26.90 33.57 a-e 23 115h 68 27.23 27.90 cde 46 146d 65 25.47 34.77 a-d 69 135e 73 28.90 25.87 cde 92 132ef 75 28.63 29.47 cde 11 response of nerica rice to nitrogen fertilization nerica10 0 131ef 68 24.13 32.70 a-e 23 127fg 79 25.13 30.93 b-e 46 143d 77 22.83 28.87 cde 69 150d 76 24.90 43.40 a 92 147d 74 25.26 42.10 ab brri dhan57 0 176b 129 18.73 22.37 e 23 167c 133 18.47 24.43 de 46 178b 151 18.57 24.30 de 69 202a 144 17.83 27.80 cde 92 203a 141 18.33 28.77 cde cv (%) 2.52 17.68 6.42 19.87 ** and * indicates significant at 1 and 5% level, ns = not significant and similar letters within the column did not differ significantly by dmrt grain yield the variety brri dhan57 with 69 kg n ha-1 produced higher yield (4.16 t ha-1) which was 53.50% higher than control plot. besides nerica1 and nerica10 did not show response with different levels of nitrogen. nerica1 with 69 kg n ha-1 produced 128.21% higher yield than 0 kg n treated plot which was statistically similar with 92 kg n ha-1, produced 127.35% higher yield than control plot. uddin et al. (2013) reported that nerica1 produced the highest grain yield (2.96 t ha-1) with 80 kg n ha-1. 0.0 0.8 1.6 2.4 3.2 4.0 4.8 0 23 46 69 92 n added (kg n ha -1 ) g ra in y ie ld (t h a-1 ) nerica 1 nerica 10 brri dhan57 fig. 1. effect of different n doses on grain yield of nerica rice. furthermore, nerica10 with 69 kg n/ha produced 127.35% higher yield than control plot which was statistically similar with 92 kg n/ha, produced 100% higher yield than control plot. it revealed that brri dhan57 responded higher with increased rate of nitrogen fertilizer but nerica1 and nerica10 have lower response with nitrogen fertilizer. kisetu et al. (2013) stated from different reports that very low response of nerica4 rice cultivar to various n levels in different parts of tanzania. straw yield brri dhan57 with 69 kg n ha-1 produced the highest straw yield (4.20 t ha-1) whereas nerica1 and nerica10 produced straw yield of 4.20 and 3.33 t ha-1 with 46 kg n ha-1 (fig. 2). irshad et al. (2000) stated that n application increased straw yield over the absolute control. 12 shultana et al. 0 0.8 1.6 2.4 3.2 4 4.8 0 23 46 69 92 n added (kg n ha -1 ) st ra w y ie ld (t h a-1 ) nerica 1 nerica 10 brri dhan57 fig. 2. effect of different n doses on straw yield of nerica rice calculation of optimum nitrogen doses for nerica rice the regression line clearly indicated the relationship among three varieties with different rates of nitrogen fertilizer. moreover, calculation for optimum nitrogen rates for three different rice varieties depicts that for getting higher yield in brri dhan57 it requires 85.75 kg n ha-1. however, nerica 1 could gave higher yield at 69.25 kg n ha-1 and nerica 10 with 74.25 kg n ha-1 but grain yield is much lower than brridhan 57 (fig. 3) agronomic use efficiency and partial factor productivity the rice var. brri dhan57 with fertilizer rates 46 kg n ha-1 showed higher agronomic use efficiency (24.5). besides, the lowest (14.6) was found in brri dhan57 with 92 kg n ha-1. in case of nerica1 variety the highest agronomic use efficiency (21.7) was found in 69 kg n ha-1. however, nerica10 showed higher agronomic use efficiency at 46 kg n ha-1 (21.3). on the other hand, the var. brri dhan57 with fertilizer rates 0 kg n ha-1 showed higher partial factor productivity (137.6) among three varieties whereas nerica1 and nerica10 showed lowest with higher rates of nitrogen level (table 2). 13 response of nerica rice to nitrogen fertilization brri dhan57: y = -0.0002x2 + 0.0343x + 2.64, r2 = 0.9723** nerica 10: y = -0.0002x2 + 0.0277x + 1.2891, r2 = 0.958** nerica 1: y = -0.0002x2 + 0.0297x + 1.1539, r2 = 0.9809 0.0 0.8 1.6 2.4 3.2 4.0 4.8 0 20 40 60 80 100 n added (kg n ha-1) g ra in y ie ld (t h a-1 ) nerica 1 nerica 10 brri dhan57 fig. 3. calculation of optimum nitrogen fertilizer dose for nerica rice table 2. agronomic use efficiency and partial factor productivity of nerica rice agronomic use efficiency (aue) (kg grain per kg n applied) partial factor productivity (pfp) (kg grain per kg n applied) n applied (kg ha-1) nerica1 nerica10 brri dhan57 nerica 1 nerica 10 brri dhan57 23 6.5 13.0 20.0 57.3 72.5 137.6 46 20.8 21.3 24.5 46.2 51.0 83.3 69 21.7 18.5 21.0 38.6 38.3 60.2 92 16.2 13.8 14.6 28.9 28.6 44.1 conclusion it could be concluded that rice var. brridhan 57 showed higher grain yield with 85 n kg/ha whereas nerica1 and nerica10 with 69.25 and 74.25 kg n ha-1 during t. aman season but this two variety gave much lower grain yield than the former one. references adigbo, s. o. and k. a. okeleye. 2006. green manuring and nitrogen fertilization effects on soil chemical properties, agronomic traits and grain yield of upland rice. moor j. agric. res. 7(1): 18.ahmed, m., m. m. islam and s. k. paul. 2005. effect of nitrogen on yield and other plant characters of local t. aman rice, var. jatai. j. agric. biol. sci. 1: 158-161. awan, k. h., a. m. ranjha, s. m. mehdi, m. sarfraz and g. hassam. 2003. response of rice line pb-95 to different npk levels. j. bio. sci. 3: 157-166. bbs (bangladesh bureau of statistics). 2013. monthly statistical bulletin of rice news on 8 december, 2011. statistics division, ministry of planning, government people’s republic of bangladesh, dhaka. p. 65. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. 2nd ed., john wiley and sons, new york. pp. 202-215. 14 shultana et al. irshad, a., g. abbas and a. khaliq. 2000. effect of different nitrogen application techniques on the yield and yield components of fine rice. int. j. agric. biol. 2(3): 239–241. kisetu, e., j. kasian and z. s. mtakimwa. 2013. determination of urea-n levels application to nerica4 cultivar of rice (oryza sativa l.) grown on soils of dakawa-morogoro, tanzania. a. int. j. of agric. sci. 1(6): 73-80. oikeh, s., s. diatta and t. tsuboi. 2008. soil fertility and nerica rice nutrition. in: somado ea, guei rg, keya so (eds) nerica: the new rice for africa compendium. africa rice centre, cotonou, benin, pp. 75–82. okeleye, k. a. and d. t. kehinde. 2009. influence of legume/rice sequence and nitrogen on nerica rice in rainfed upland and lowland ecologies of west africa. the proceedings of the international plant nutrition colloquium xvi, department of plant sciences, uc davis. university of agriculture, abeokuta, nigeria. russell, d. f. 1986. mstat-c computer based data analysis software).crop and soil science department, michigan state university, usa. uddin, s., m. a. r. sarkar and m. m. rahma. 2013. effect of nitrogen and potassium on yield of dry direct seeded rice cv. nerica1 in aus season. int. j. agron. plant prod. 4(1): 69–75. bangladesh agron. j. 2015, 18(2): 39-44 response of t. aman and boro rice to residue retention under strip tillage m. m. hossain1*, m. begum1, m.m. rahman1 and a. hashem2 1department of agronomy, bangladesh agricultural university 2department of agriculture and food, western australia *corresponding author and e-mail address: mmhshakil@yahoo.com key words: unpuddled transplanting, conventional tillage, strip tillage, residue retention abstract an on-farm research was conducted at gouripur upazila under mymensingh district of bangladesh during aman and boro season in 2013-14 to evaluate the performance of unpuddled rice cultivation. the rice var. hybrid krishan2 in aman and brri dhan28 in boro season were transplanted by two tillage practices viz., conventional tillage (ct) and strip tillage (st) and two levels of crop residue i.e, no residue (r0) and 50% residue (r50). the experiment was designed in a randomized complete block design with four replications. st yielded higher grains in aman season (5.67 t ha-1) and also in boro season (4.70 t ha-1) which were 9 and 13% higher compared to ct. higher grain yield in st leading to 26% higher bcr in aman and 23% higher in boro compared to ct. retention of 50% residue increased by 5% yield in aman and by 4% yield in boro compared to no residue which contributed to 9% higher bcr in both aman and boro. st combine with 50% residue retention yielded the highest grain yield in both of aman (5.97 t ha-1) and boro season (4.81t ha-1) which attributed to obtain the highest bcr in aman (3.08) and boro (2.78). introduction most of the farmers in the asian continent cultivate rice (oryza sativa l.) seedlings by transplanting in puddled soil for easy crop establishment (singh et al., 2014). lands are prepared by single or two passes in dry condition followed by exposure to sun for a couple of days. then after inundation, final land is prepared by ploughing, cross ploughing and laddering in standing water. however, this traditional puddling method is labour, fuel, time and capital consuming (islam et al., 2014). nowadays most of tillage operations for puddling soil in bangladesh are done by power tiller (haque et al. 2008; miah et al., 2002). puddling is detrimental to soil physical conditions (hobbs and morris, 1996) through destroying soil aggregates, breaking capillary pores, and dispersing the soils (gupta et al., 2003). cloddy soil structure with less soil moisture and inadequate seed-soil contact resulted from the puddling (sharma et al., 1995) makes land preparation difficult for the following winter crops (islam et al. 2014). puddled rice transplanting consumes about 20-40 % of total water required for raising crop (singh et al., 2014) and it also promotes the formation of hard pan (bhuiyan et al., 1995), reduces soil organic carbon at double rate, and decreases soil fertility (grace, 2003), has losses of irrigation water (sayre and hobbs, 2003), and damages the ecological environment (grace, 2003). adoption of minimum tillage may be a very good alternative to puddled transplanting as it is using widely for many crops around the world (singh et al., 2014). this technology has potentials to allow saving in labour, energy, water and time during rice establishment (piggin et al., 2002). compared to conventional tillage, 25-26% water could be saved by strip tillage under unpuddled system (islam et al., 2012). crop residues of cultivated crops are a significant factor for crop production through their effects on soil physical, chemical and biological functions as well as water and soil quality and increase crop yield (kumar and goh, 2000). residue practice maintains soil micro-organisms and microbial activity which can also lead to weed suppression by the biological agents leading to increase crop yield (kennedy, 1999). considerable research work has been done on puddle transplanting, but there is alimited information on unpuddled rice transplanting under bangladesh 40 hossain et al. condition. therefore, the present study was conducted to examine the performance of rice to unpuddled transplanting system with the retention of crop residues. materials and methods the experiment was conducted at farmer’s field of durbacahra, guipure, mymensingh, bangladesh (the latitude of 24.750 n and the longitude of 90.500 e) during aman (july-mid november) and boro (mid november-june) season in 2013-14. this experimental area belongs to the old brahmaputra floodplain which is characterized by dark grey non calcareous alluvium soils and these soils are mostly sandy loam under sonatala series (brammer, 1996). climatic (rainfall and thermal condition) data were collected from the nearest weather station and are presented in figure 1. 0 50 100 150 200 250 300 350 400 0 5 10 15 20 25 30 35 40 r a in fa ll ,m m t em p er a tu re ,0c month rainfa ll max temp min temp fig.1. monthly temperature and rainfall distribution pattern in gouripur during the cropping season of 2013-14 [source: department of irrigation and water management, faculty of agricultural engineering and technology, bangladesh agricultural university, mymensingh] the treatments were: (i) ipuddled condition conventional tillage (ct) and (ii) unpuddled condition strip tillage (st) and two levels of crop residue viz., no residue (r0) and 50% residue (r50). the treatments were laid out in randomized complete block design with four replications using unit plots of 9 m × 5 m. in tillage practice, ct consisted of two passes primary tillage by two wheeler tractor (2 wt) and exposed to sun for two days followed by inundating whole plot and puddling by 2wt with two passes to complete land preparation. st was done by versatile strip tillage planter (vstp) in single pass operation before inundating the field. three days before st, pre-plant glyphosate (roundup) was applied @ 75 ml / 10 l water. after st, the land was inundated with 3-5 cm standing water one day before transplanting operation for making the land soft enough to transplant seedlings (islam et al., 2014). twenty-five days old seedlings of rice var. hybrid krishan2 for aman season, and 40 days old seedlings of brri dhan28 for boro season were transplanted. fertilizers were applied according to the recommendation of brri (2014). a spacing of 25 cm × 15 cm was maintained for both ct and st with 2 or 3 seedlings hill-1. the crops were harvested at maturity from 3m × 3m each and then data were recorded. grain yields were adjusted to 14% moisture content. data were subjected to anova using mstat-c and means separated by duncan's multiple range test. results and discussions effect of tillage practice on yield contributing characters and yield of rice 41 response of t. aman and boro rice to residue retention under strip tillage yield contributing characters of rice were significantly affected due to different tillage practice except the plant height, panicle length, and thousand grain weight (table 1). the highest numbers of effective tillesr m-2 and numbers of fertile grains panicle-1, and the lowest numbers of non-effective tillesr m-2 and numbers of sterile grains panicle-1 were recorded from the st compared to ct which attributed to higher yield (9% higher in aman and 13% higher in boro) for st (table 1). on the other hand, unpuddled rice transplanting by following st produced higher bcr (around 25% in aman and 23% higher in boro compared to ct (table 1). table 1. effect of tillage practice on yield contributing characters and yield of rice tillage practice plant height (cm) effective tillers m-2 (no) non effective tillers m-2 (no) panicle length (cm) fertile grains panicle-1 (no) sterile grains panicle-1 (no) 1000grain weight (gm) grain yield (t ha-1) benefit cost ratio aman season ct 110.42 209b 71a 24 139b 47a 30 5.18a 1.76b st 109.99 261a 44b 25 157a 29b 31 5.67b 2.21a lsd (0.05) ns 1.37 12.41 ns 5.48 2.55 0.41 0.22 0.13 cv (%) 2.74 12.67 11.71 2.40 3.47 2.27 1.32 0.34 4.72 boro season ct 107.32 361b 77a 23.92 111b 35a 21.91 4.17b 2.16b st 105.60 382a 47b 24.39 132a 16b 23.00 4.70a 2.67a lsd (0.05) ns 4.60 3.00 ns 8.29 2.90 ns 0.09 0.03 cv (%) 4.60 1.20 5.68 3.84 5.14 8.88 6.83 2.10 1.24 in a column, figure with similar letter do not differ significantly whereas dissimilar letter differ significantly. ct= conventional tillage, st= strip tillage, effect of residue retention on yield contributing characters and yield of rice retention of 50% residue improved the numbers of effective tiller m-2 and the numbers of fertile grain panicle-1 while declined the numbers of non-effective tiller m-2 and the numbers of sterile grain panicle-1, compared to no residue in both aman and boro season (table 2). higher residue level yielded around 5% higher grains of hybrid krishan2 and 4% higher grains of brri dhan28 rice which attributed to earned 9% higher bcr in both aman and boro season (table 2). table 2. effect residue level on yield contributing characters and yield of rice residue level plant height (cm) effective tillers m-2 (no) non effective tillers m-2 (no) panicle length (cm) fertile grains panicle-1 (no) sterile grains panicle-1 (no) 1000 grain weight (gm) grain yield (t ha-1) benefit cost ratio aman season r0 110.60 236b 53 24.59 148b 33a 31.70b 5.50b 2.61b r50 109.52 265a 40 24.51 157a 29b 32.06a 5.76a 2.86a lsd (0.05) ns 0.79 ns 0.31 3.16 1.47 0.23 0.13 0.75 cv (%) 2.74 12.67 11.71 2.40 3.47 2.27 1.32 0.34 4.72 42 hossain et al. boro season r0 104.90 373b 58b 24.39 100a 22a 22.71 4.52b 2.48b r50 106.37 385a 46a 24.25 121e 17b 22.93 4.70a 2.69a lsd (0.05) ns 2.65 1.73 ns 4.78 1.67 ns 0.05 0.018 cv (%) 4.60 1.20 5.68 3.84 5.14 8.88 6.83 2.10 1.24 in a column, figure with similar letter do not differ significantly whereas dissimilar letter differ significantly. r0= no residue, r50= 50% residue, combination effect of tillage practice and residue level on yield contributing characters and yield of rice combination between tillage practice and residue level exerted significant effect on all the plant characters except plant height, panicle length and weight of thousand grain in both aman and boro season (table 3). st retained 50% residue produced the highest number of effective tillers m-2, and number of fertile grains panicle-1, and the lowest numbers of non-effective tiller m-2 and number of sterile grains panicle-1 for both in aman and boro season. ct or st with residue yielded the higher values of these parameters compared to no residues. st with residue yielded the highest grain yield leading to the highest bcr while ct without residue yielded the lowest grain yield consequently the lowest bcr both in aman and boro season. table 3. combination effect of tillage practice and residue level on yield contributing characters and yield of rice tillage practice residue level plant height (cm) effective tillers m-2 (no) non effective tillers m-2 (no) panicle length (cm) fertile grains panicle1 (no) sterile grains panicle-1 (no) 1000 grain weight (gm) grain yield (t ha-1) benefit cost ratio aman season r0 109.30 207cd 78d 24.20 119d 53a 28.50 5.17cd 1.63cct r50 111.55 211 c 63c 24.60 140c 43b 31.28 5.20c 1.76c r0 110.87 241b 49b 24.67 154b 29c 30.84 5.57b 2.76bst r50 109.12 280a 35a 24.50 160a 26c 31.37 5.97a 3.08a lsd (0.05) ns 1.95 10.88 ns 5.76 3.60 ns 0.32 0.18 cv (%) 2.74 12.67 11.71 2.40 3.47 2.27 1.32 0.34 4.72 boro season r0 108.35 359 84a 24.35 100c 41a 21.60 4.12d 2.08dct r50 106.30 363 70b 24.50 121b 30b 22.23 4.24c 2.24c r0 104.21 376 53c 24.40 129ab 18c 22.93 4.60b 2.56bst r50 106.38 388 41d 24.20 139a 15c 23.07 4.81a 2.78a lsd (0.05) ns 6.50 4.25 ns 11.72 4.11 ns 0.13 0.045 cv (%) 4.60 1.20 5.68 3.84 5.14 8.88 6.83 2.10 1.24 in a column, figure with similar letter do not differ significantly whereas dissimilar letter differs significantly. ct= conventional tillage, st= strip tillage, r0= no residue, r50= 50% residue the higher rice yields in st obtained in this study are in the conformity with results of mahajan et al. (2002) and heatherly et al. (1994) residue converts to mineralized nutrients which causes sufficient crop growth and facilitates higher yield over no residue (shrivastav, 2014 and dahal, 2014). straw for controlling weeds in different crops have been suggested by devasinghe et al. (2011). residues prevents weed growth and supplies organic matter for heterotrophic n fixing microorganisms, which could be utilized by succeeding crops consequently results the higher yield (mendoza and samson, 1999; patnaik, 1978). conclusion 43 response of t. aman and boro rice to residue retention under strip tillage considering the rice grain yield and bcr, it may be concluded that, unpuddled rice transplantation may be a good alternative to existing conventional practice. farmers are likely to be benefited with the adoption of unpuddled system with the retention of crop residues in the field. references bhuiyan, s. i., m. a. sattar, and d. f. tabbal. 1995. wet seeded rice: water use efficiency and productivity and constraints to wider adoption. in moody (ed) constraints, opportunities and innovations for wet seeded rice, los banos (phillipines): irri. pp: 143-55. brammer, h. 1996. the geography of the soils of bangladesh. university press limited, dhaka, bangladesh. devasinghe, d. a. u. d., k. p. premarathne and u. r. sangakkara. 2011. weed management by rice straw mulching in direct seeded lowland rice (oryza sativa l.). tropical agric. res. 22 (3): 263 272. grace, p. r. 2003. rice-wheat system and climatic change. addressing resource conservation issues in rice-wheat systems of south asia: a resource book. rice-wheat consortium for the indo-gangetic plains. international maize and wheat improvement center, new delhi, pp. 63-67 gupta, r. k., p. r. hobbs, l. harrington and j. k. ladha. 2003. rice-wheat system: problem analysis and strategic entry points, addressing resource conservation issues in rice-wheat systems of south asia: a resource book, rice-wheat consortium for the indo-gangetic plains international maize and wheat improvement centre, new delhi, pp.16-23. haque, m. e., m. i. hossain, m. a. wohab, k. d. sayre, r. w. bell and j. timsina. 2008. agricultural mechanization in bangladesh and conservation agriculture: the opportunities, priorities, practices and possibilities. forth international conference of conservation agriculture. february 2009, new delhi, india. heatherly, l. g., c. d. elmore and s. r. spurlock, 1994. effect of irrigation and weed control treatment on and net return from soybean (glycine max l.). weed technol. 8: 69-76. hobbs, p. and m. morris 1996. meeting south asia’s future food requirement from rice-wheat cropping systems: issues facing researchers in the post-green revolution era. nrg paper 96-01 mexico, d.f., cimmyt. islam, a. k. m. s., m. m. hossain and m. a., saleque. 2014. effect of unpuddled transplanting on the growth and yield of dry season rice (oryza sativa l.) in high barind tract. the agriculturists. 12(2): 91-97. islam, a. k. m. s., m. m. hossain, m. a. saleque, m. a. rahman, b. karmakar and m. e. haque. 2012. effect of minimum tillage on soil properties, crop growth and yield of aman rice in drought prone northwest bangladesh. bangladesh agron. j. 15(1): 43-51. kennedy, a. c. 1999. soil microorganisms for weed management. j. crop prod. 2: 123–138. kumar, k. and k. m. goh. 2000. crop residues and management practices: effects on soil quality, soil nitrogen dynamics, crop yield and nitrogen recovery. adv. agron. 68: 198–279. mahajan, g., l. s. brar and u. s. walia. 2002. phalaris minor response in wheat in relation to planting dates, tillage and herbicides. indian j. weed sci. 34: 213-215. mendoza, t. c. and r. samson. 1999. strategies to avoid crop residue burning in the philippine context. in: international conference of “frostbite and sun burns” canadian international initiatives toward mitigating climate change hosted by internation program (ip) of the camadia environmental network (cen) and the salvadorn center for appropriate technology (cesta) held on 24 april–may 2. p.13. 44 hossain et al. miah, m. a. m., m. s. islam and m. t. h. miah. 2002. socio-economic impacts of farm mechanization on the livelihoods of rural labourers in bangladesh. j. farm econ. 12: 147-162. patnaik, s. 1978. natural sources of nutrients in rice soils. in soil and rice. p. 501–20. irri, los banos, laguna, philippines. piggin, c. m., c. o. gracia and j. d. janiya. 2002. establishment of irrigated rice under zero and conventional tillage system in the philippines. in proc. int. workshop on herbicide resistance management and zero tillage in rice-wheat system. march 4-6, hisar, india, 190-95. sayre, k. d. and p. hoobs. 2003. raised bed system of cultivation for irrigated production condition bed planting course, cimmyt, mexico. sharma, p. k., k. t. ingram and d. harnpichitvitaya. 1995. subsoil compaction to improve water use efficiency and yields of rainfed lowland rice in coarse–textured soils. soil and tillage res. 36: 33–44. shrivastav, n. 2014. weed dynamics and productivity of spring maize under different tillage and weed management methods. m.sc. ag. thesis, tribhuvan university, department of agronomy, iaas, rampur, chitwan, nepal. singh, a., r. kumar and j. s. kang. 2014. tillage system, crop residues and nitrogen to improve the productivity of direct seeded rice and transplanted rice. curr. agri. res. j. 2(1): 14-29. bangladesh agron. j. 2014, 17(1): 33-40 yield performance of lentil as a mixed crop with rapeseed m. s. islam1, m. a. islam1*, m. a. begum2, m. maniruzzaman1 and m. a. u. alam1 1on farm research division, bangladesh agricultural research institute, agricultural research station, pabna, 2department of agronomy, bangladesh agricultural university, mymensingh, *corresponding author: amin_bau@yahoo.com key words: lentil, lentil equivalent yield, mixed cropping, rapeseed abstract mixed crop cultivation of lentil and rapeseed could be a promising technology for yield maximization. the field experiment was carried out at multilocation testing site, kashinathpur, pabna during the rabi season of 2011-12 and 2012-13 to verify the performance of rapeseed as mixed crop with lentil at different seeding ratios. the treatment comprises for the experiment were t1: sole lentil (100%), t2: sole rapeseed (100%), t3: lentil (100%) + rapeseed (10%), t4: lentil (100%) + rapeseed (20%), t5: lentil (100%) + rapeseed (30%) and t6 :farmers’ practice :lentil (100%) + rapeseed (15%). the highest lentil equivalent yield (2.22 t ha-1 in and 2.48 ) and maximum land equivalent ratios (1.27 and 1.28) were observed in t4 treatment in 2011-12 and 2012-13, respectively.. it was noted that all the mixed cropping systems produced higher equivalent yield and ler than that of their corresponding sole crops. . cost and return analysis showed that the highest net return (tk. 127774 ha-1) was found in t4 treatment while sole rapeseed gave the lowest net return (tk. 60540 ha-1). net return was always higher under mixed cropping system than that of sole cropping. the highest benefit cost ratio 3.48 was recorded from lentil (100%) + rapeseed (20%) where as the minimum (1.39) from soli rapeseed.. introduction lentil (lens culinaris) is one of the important pulse crops, which ranks the first position regarding area and production in bangladesh (bbs, 2010). it is one of the most important sources of protein both as food and feed. it also produces more stable yield and can be grown with minimum care. lentil is generally grown as sole crop but it can also be grown as mixed or intercrop with maize, mustard, wheat, barley etc. on the other hand, mustard (brassica spp.) is an important oil crop, which also ranks first position among the oil crops in bangladesh (bbs, 2010). mixed cropping is the agricultural practice of cultivating two or more crops in the same piece of land at the same time (ofori and stern, 1987; anil et al., 1998). it offers effective weed suppression, pest and disease control, and use of soil resources under organic farming systems (bulson et al., 1997; theunissen, 1997; jensen et al., 2005). an ideal intercropping or mixed cropping system should aim to i) produce higher yields per unit area through better use of natural resources, minimizing the incidence of insect pests, diseases weeds and improving the nitrogen economy in legume associations, ii) offer greater stability and crop insurance in production under aberrant weather condition, iii) meet the domestic need of farmers and animal iv) provide an equitable distribution of farm resources (ali, 1990). so, this trial was planned to evaluate the technological feasibility and economic validity of mixed cropping lentil with rapeseed at different seeding rates of rapeseed. materials and methods the experiment was carried out at mlt site, kashinathpur, pabna in the rabi season of 2011-12 and 2012-13. the soils of the experimental areas belong to the high ganges river flood plain under aez-11. mailto:amin_bau@yahoo.com 34 islam et al. the soils of the experimental plots were sandy clayey loam in texture. the experiment was laid out in randomized complete block (rcb) design with six dispersed replications. it was consisted with six treatments as follows: t1: sole lentil (100% lentil), t2: sole rapeseed (100 % rapeseed), t3: lentil (100%) + rapeseed (10%), t4: lentil (100%) + rapeseed (20%), t5: lentil (100%) + rapeseed (30%) and t6: lentil (100%) + rapeseed (15%). seed rate 30 kg ha-1 for lentil and 10 kg ha-1 for rapeseed was considered for crop, respectively. to obtain 10, 15, 20, 30% rapeseed, amount of seed mixed with lentil was calculated as 1, 1.5, 2.0 and 3.0 kg ha-1. the calculated amounts of rapeseed were mixed with 30 kg of lentil seeds separately for achieving different treatment combinations (i.e. t3, t6, t4 and t5 treatments). seeds of lentil (barimasur7) and rapeseed (barisarisha14) were sown on 10th to17th november in 2011 and 2nd to 5th november in 2012 as broadcast. the unit plot size was 7.5m x 4m. the lands were fertilized with 19, 16, 20, 7, 1.5 and 1.5 kg n-p-k-s-zn-b ha-1 respectively for sole lentil and mixed cropping and 115, 34, 43, 27, 2.5 and 2.5 kg n-p-k-s-zn-b ha-1 for sole rapeseed. all the fertilizers of entire amount was applied during final land preparation as basal except t2 (sole rapeseed) as one third urea was applied as top dress at about 30 das on 20th to 22nd december, 2011 and 2nd to 5th december, 2012. the treatments were evaluated in terms of land equivalent ratio (ler) using the following formula of willey (1981). ler = ------------------------------------ + ------------------------------------- also, rapeseed yields were converted into lentil equivalent yield as per anjeneyula et al. (1982). lentil yield equivalent y = ----------- where, yl = yield of lentil, pl and pm = market prices of lentil and rapeseed, respectively. the recorded data were statistically analyzed following gomez and gomez (1984). all types of variable production cost are recorded to find out the benefit cost ratio (bcr). results and discussion yield and yield attributes of lentil the results revealed that most of the yield attributes of lentil were significantly influenced due to mixed cropping with rapeseed except plant population (table 1). higher plant height (48.10 cm in 2011-12 and 50.63 cm in 2012-13) was obtained from t1 treatment followed by t3. the maximum number of pod plant-1 (57.18 in 2011-12 and 46.55 in 2012-13) was recorded in t1 which was statistically identical to t3, t4 and t6 treatments and the lowest number of pod plant-1 from t5 treatment. pods plant-1, number of seeds pod-1 was found significant in all the treatment combination in 2011-12 but statistical similarity in 2012-13 except t5 treatment. in 2011-12 cropping season, 1000seed weight was statistically similar in t1, t3, t4 and t6 but numerically higher 1000 seed weight (18.55g) was obtained from t3 and the lower (17.87g) from t5 treatment where as in 2012-13 while maximum in t1 (18.91 g) followed by t3 (18.33 g), t4 (18.32 g) and t6 (18.23 g) and the lowest (17.26 g) in t5 treatment. t1 treatment produced the highest seed yield (1.90 t ha-1) in 2011-12 and 2.04 t ha-1 in 2012-13. the maximum seed yield in t1 might be due to cumulative effect of yield contributing characters i.e. number of pod plant-1, number of seeds pod-1 and 1000seed weight. yield of intercropped lentil yield of solecropped lentil yield of intercropped rapeseed yield of solecropped rapeseed yl x pl pm 35 mixed cropping of lentil with rapeseed table 1. seed yield and yield attributes of lentil as a mixed crop with rapeseed treatments plant height (cm) plant population m-2 number of pods plant-1 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 t1 48.10 50.63 119.96 126.1 57.18 46.55 t3 42.93 45.19 114.57 124.1 53.80 45.78 t4 42.29 44.52 118.48 123.1 48.56 45.70 t5 39.16 41.22 110.70 121.2 39.44 43.84 t6 40.36 42.48 114.97 122.2 51.33 44.42 lsd(0.05) 2.512 0.643 ns ns 11.74 0.198 cv (%) 3.99 6.26 10.33 4.25 12.66 6.8 table 1. (continued) treatments number of seeds pod-1 1000seed weight (g) seed yield (t ha-1) 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 t1 1.68 1.65 18.32 18.91 1.90 2.04 t3 1.75 1.65 18.55 18.33 1.73 1.91 t4 1.72 1.65 18.25 18.32 1.80 1.91 t5 1.67 1.55 17.87 17.26 1.57 1.59 t6 1.70 1.65 18.53 18.23 1.78 1.82 lsd(0.05) 0.053 0.038 0.241 0.107 0.038 0.174 cv (%) 2.47 2.89 3.69 2.50 7.10 5.60 yield and yield attributes of rapeseed data as presented in the table 2 revealed that yield and yield contributing characters of rapeseed were differed significantly different. there was an increasing trend of plant population with the increase of seed ratio in all the treatments. the maximum plant population (84.94 and 99.40) was observed in t2 treatment followed by t5 and the lowest plant population (10.40 and 22.21) from t3 treatment in 2011-12 and 2012-13,respectively. the maximum number of siliqua plant-1 (45.00) were found in t3 which was statistically similar to t6, t4 and t5 and the minimum (30.43) from t2 treatment during 2011-12. similar trend was observed in 2012-13. in 2011-12, the highest number of seeds siliqua-1 (32.34) was obtained from t4 followed by t6 as well as the lowest (29.83) was recorded from t2. more or less similar results were recorded in 2012-13. from two years result showed that there was no significant difference among the treatment regarding 1000seeds weight (g) but numerically higher 1000seeds weight (2.93 g in 2011-12 and 2.79 g in 2012-13) was observed in t3 followed by t2 and t6 but the lower (2.75 g in 201112 and 2.73 g in 2012-13) from t5 treatment. the maximum seed yields 1.65 t ha-1 and 2.12 t ha-1 were obtained in t2 followed by t5 due to higher plant population where as the minimum seed yield (0.50 t ha1 in 2011-12 and 0.55 t ha-1 in 2012-13) was obtained from t3 treatment, which were statistically similar to t6. table 2. seed yield and yield attributes of rapeseed as a mixed crop with lentil treatments plant height (cm) plant population m-2 no. of siliquae plant-1 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 t2 74.71 82.64 84.94 99.40 30.43 30.48 t3 78.16 86.46 10.40 22.21 45.00 34.50 36 islam et al. t4 76.13 84.22 20.94 30.80 39.63 33.92 t5 72.72 80.44 33.37 39.20 37.50 31.14 t6 78.42 83.44 16.33 26.01 41.73 33.68 lsd(0.05) 0.975 2.19 2.776 2.257 9.357 2.063 cv (%) 7.63 6.45 5.77 6.87 12.89 5.70 table 2. (continued) treatments no. of seeds siliqua-1 1000-seed weight (g) seed yield (t ha-1) 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 t2 29.83 28.66 2.90 2.77 1.65 2.12 t3 30.67 29.98 2.93 2.79 0.50 0.55 t4 32.34 28.38 2.77 2.76 0.53 0.72 t5 30.20 27.64 2.75 2.73 0.62 0.82 t6 30.90 29.92 2.80 2.77 0.50 0.63 lsd(0.05) 0.059 1.668 ns 0.042 0.059 0.261 cv (%) 5.11 4.30 7.72 3.65 6.29 12.08 lentil equivalent yield and land equivalent ratio (ler) data presented in the table 3 revealed that the equivalent yield of lentil was differed from each other among the treatments in both the consecutive years. the maximum lentil equivalent yield (2.22 t ha-1) was obtained from t4 followed by t6 and t3 and the lowest lentil (1.30 t ha-1) in t2 treatment in 201112. similar trends were observed in 2011-12. the highest lentil equivalent yield (2.48 t ha-1) was obtained from t4 followed by t6 and t3 and the lowest lentil equivalent yield (1.67 t ha-1) was recorded in t2 treatment. it was noted that all the mixed cropping system produced higher equivalent yield than that of their corresponding sole crops. results from both the years indicated that t4 treatment was found higher yield advantageous as well as profitable over other treatments. similar observations in different mixed/intercropping systems were reported by other authors (ali et al., 2007, patra et al., 2000; islam et al., 2008 and alom et al., 2008). the maximum land equivalent ratio (ler) 1.27 and 1.28 were observed in 2011-12 and 2012-13, respectively from the t4 treatment followed by t6 . it is noted that all the mixed cropping systems showed higher ler than sole crop. it could be said that a farmer may increase his land use efficiency by 27 to 28% from mixed cropping systems from growing one hectare of land than that of their traditional sole crops cultivation. the results are in agreement with that of santalla et al. (2001), basak et al. (2006), razzaque et al. (2007) and alom et al. (2008). table 3. lentil equivalent yield and land equivalent ratio (ler) of mixed cropping entil with rapeseed treatments 2011-12 2012-13 seed yield (t ha-1) lentil equivalent yield (t ha-1) ler seed yield (t ha-1) lentil equivalent yield (t ha-1) ler lentil rapeseed lentil rapeseed t1 1.90 1.90 1.00 2.04 2.04 1.00 t2 0.00 1.65 1.30 1.00 2.12 1.67 1.00 t3 1.73 0.50 2.13 1.21 1.91 0.55 2.34 1.20 t4 1.80 0.53 2.22 1.27 1.91 0.72 2.48 1.28 t5 1.57 0.62 2.05 1.20 1.59 0.82 2.23 1.17 t6 1.78 0.50 2.18 1.24 1.82 0.63 2.32 1.19 cost benefit analysis 37 mixed cropping of lentil with rapeseed data of cost and return analysis (average of two years) are presented in the table 4. it showed that the highest gross return (tk.164500 ha-1) and net return (tk.127774 ha-1) were found maximum in t4 followed by t6 and t3 while sole rapeseed produced the lowest gross return (tk.103950 ha-1) as well as net return (tk.60540 ha-1). the cost of cultivation was found higher in sole rapeseed cultivation as it required more fertilizers, irrigation and labour costs than that of lentil cultivation. net return was higher than mixed cropping system than that of sole cropping. many investigators also reported higher net return in mixed/intercropping systems than sole crop (quayyum and maniruzzaman, 1995; sarker and pal, 2004; basak et al., 2006; razzaque et al., 2007; pyare et al., 2008 and alom et al., 2008). the highest benefit cost ratio (3.48) was recorded from t4 where as the minimum bcr (1.39) from t2 treatment. table 4. cost and return analysis obtained from the experimentation (average of two years) treatments lentil equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) net return (tk. ha-1) benefit cost ratio (bcr) t1 1.97 137900 36464 101436 2.78 t2 1.49 103950 43410 60540 1.39 t3 2.24 156450 36595 119855 3.28 t4 2.35 164500 36726 127774 3.48 t5 2.14 149800 36857 112943 3.06 t6 2.25 157500 36661 120840 3.30 price of input (tk. kg-1) price of output (tk. kg-1) seed 110 lentil grain 70.0 urea 20.0 rapeseed 55.0 tsp 24.0 mop 15.0 gypsum 10.0 znso4 130.0 boric acid 130.0 conclusion lentil equivalent yield was increased with the increase in percent of rapeseed up to 20% with 100% lentil and thereafter it declined with further increment in seeds. all the mixed crop combinations showed higher gross return as well as net return than the respective sole crops. considering the yield and return it can be concluded that treatment t4 viz. 100% lentil with 20% rapeseed (30 kg lentil with 2.0 kg rapeseed per hectare) was the most profitable one compared to other treatments when grown as mixed crop. furthermore, mixed cropping was found more profitable than the sole. references ali, m. 1990. pigeonpea: cropping systems. the pegionpea cab international icrisat, patancheru, a.p. 502324, india. pp.281-282. ali, m. o., m. j. alam, m. s. alam, m. a. islam and m. shahin-uz-zaman. 2007. study on mixed cropping mungbean with sesame at different seeding rates. intl. j. sustain. crop prod. 2: 74-77. 38 islam et al. alom, m. s., n. k. paul, and m. a. quayyum. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean (vigna radiata l.) in different planting methods. saarc j. agri. 6: 73-82. altieri, m. a. 1999. the ecological role of biodiversity in agroecosystems. agric. ecosys. environ.74 : 19-31. altieri, m. a., d. k. letourneau and j. r. davis. 1983. developing sustainable agroecosystems. biosci. 33: 45-49. anil, l., j. park, r. h. phipps and f. a. miller. 1998. temperate intercropping of cereals for forage: a review of the potential for growth and utilization with particular reference to the uk. grass forage sci 53: 301-317. anjeneyula, v. r., s. p. singh and m. ali. 1982. effect of competition free period and technique and pattern of pearl millet planting in growth and yield of mungbean and total productivity in solid pearl millet and pearl millet/mungbean intercropping systems. indian j. agron. 27: 219-226. bangladesh bureau of statistics (bbs). 2010. yearbook of agricultural statistics of bangladesh. reproduction, documentation and publication wing, bbs, secretariat, dhaka. basak, n. c., s. m. a. hossain, i. islam and n. i. bhuiyan. 2006. intercropping wheat with groundnut at variable plant population bangladesh j. agril. res. 31: 207-215. bulson, h. a. j., r.w. snaydon and c. e. stopes. 1997. effects of plant density on intercropped wheat and filed beans in an organic farming system. j agr. sci 128: 59-71. chowdhury, s. l. 1981. recent studies in intercropping systems on proceedings of the india-some thoughts, some results. in: proceed. intl. workshop intercrop., 10-13 january, 1979 icrisat, patancheru, a.p. 502324, india. pp.299-305. gomez, k. a. and a. a. gomez. 1984. statistical proc. agric. res. (2nd edition), jhon willey and sons, new york. islam, m. n. and m. akteruzzaman. 2008. survey on multiple cropping systems in farmers field. in: annual research report 2007-08, agronomy division, bari, joydebpur, gazipur. pp.44-48. jensen, e. s., h. hauggaard-nielsen, j. kinane, m. k. andersen and b. jornsgaard. 2005. intercropping – the practical application of diversity, competition and facilitation in arable organic cropping systems. in: kopke u, niggli u, neuhoff d, lockeretz w, willer h (eds) researching sustainable systems 2005. proceedings of the first scientific conference of the international society of organic agricultural research (isofar), bonn, germany, 2005, pp.22-25. jackson, l. e., u. pascual and t. hodgkin. 2007. utilizing and conserving agrobiodiversity in agricultural landscapes. agro. eco. env. 121: 196-210. mcgilchrist, c. a. and b. r. trenbath. 1971. a revised analysis of plant competition experiments. biometrics 27: 659-671. malézieux, e., y. crozat, c. dupraz, m. laurans, d. makowski, h. ozier-lafontaine, b. rapidel, s. tourdonnet and m. valantin-morison. 2009. mixing plant species in cropping systems: concepts, tools and models. a review. agron. sustain. dev. 29: 43-62. ofori, f. and w. r. stern. 1987. cereal-legume intercropping systems. adv. agron. 41: 41-90. patra, b. c., b. k. mandal and a. l. padhi. 2000. production potential of winter maize (zea mays l.) based intercropping systems. indian j. agric. sci. 70: 2003-2006. pyare, r., k. prasad, s. kumar, r. k.tiwari and t. c. sonkar. 2008. production potential and economics of lentil (lens esculenta) and mustard (brassica juncea) in mixed and intercropping system. plant archives 8(1). pp.233-236. quayyum, m. a. and a. f. m. maniruzzaman. 1995. effect of maize (zea mays l.) and rice (oryza sativa) with blackgram (phaseolus mungo). indian j. agron. 40(1): 20-25. http://www.cabdirect.org/search.html?q=au%3a%22sarvind+kumar%22 http://www.cabdirect.org/search.html?q=au%3a%22sonkar%2c+t.+c.%22 http://www.cabdirect.org/search.html?q=do%3a%22plant+archives%22 http://www.cabdirect.org/search.html?q=do%3a%22plant+archives%22 39 mixed cropping of lentil with rapeseed razzaque, m. a., s. rafiquzzaman, m. m. m. bazzaz, a. ali and m. m. r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agril. res. 32(1): 3743. santalla, m., a. p. rodino, p. a. casquero and a. m. de ron. 2001. interactions of bush bean intercropped with field and sweet maize. european j. agron. 15: 185-196. sarkar, r. k. and p. k. pal. 2004. effect of intercropping rice (oryza sativa) with groundnut (arachis hypogaea) and pigeonpea (cajanas cajan) under different row orientations on rainfed uplands. indian j. agron. 49(3): 147-150. scherr, s. j. and j. a. mcneely. 2008. biodiversity conservation and agricultural sustainability: towards a new paradigm of ‘ecoagriculture’ landscapes. phil. trans. r. 363: 477-494. thrupp, l. a. 2002. linking agricultural biodiversity and food security: the valuable role of agrobiodiversity for sustainable agriculture. intl. aff. 76: 283-297. theunissen, j. 1997. intercropping in field vegetables as an approach to sustainable horticulture. outlook agr. 26: 9599. willey, r. w. 1981. a scientific approach to intercropping research. in: proc. intl. workshop intercrop. 10-13 january, 1979, icrisat, patancheru, a.p. 502324, india. pp.4-14. willey, r. w. and m. r. rao. 1981. a competitive ratio for quantifying competition between intercrops. expt. agric. 16: 117-125. 40 islam et al. salinity bangladesh agron. j. 2016, 19(2): 21-27 dry matter production and seed yield of soybean as affected by post-flowering salinity and water stress m.s.a. khan1, j.a. chowdhury1, m.a. razzaque2, m.z. ali1, s.k. paul1 and m.a. aziz1 1agronomy division, bangladesh agricultural research institute (bari), gazipur-1701 2training and communication wing, bari, gazipur-1701 corresponding author: shawquatshahadat@yahoo.com key words: salinity stress, water stress, post-flowering, soybean abstract the experiment was conducted in a vinyl house of the agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur, during rabi season of 2015-2016 to evaluate the sensitivity of different post-flowering growth stages of soybean to salinity (100 mm nacl) and water stress (70% depletion of available water) imposed at 4th to 6th, 6th to 8th, 8th to 10th and 10th to 12th weeks after emergence. shoot dry weight was found more sensitive to salt and water stress than root dry weight at all the post flowering growth stages. the highest relative shoot dry weight (91.47%) and relative root dry weight (95.58%) were recorded from salt and water stressed plants, respectively when both the treatments imposed at 4th to 6th weeks after emergence. the highest seed yield (10.47 g plant-1 ) was obtained from the control treatment followed by that (8.68 g plant-1) under salt stress treatment imposed at 10th to 12th weeks after emergence. contrary, the lowest seed yield of 0.69 g plant-1 was obtained from the salt stress treatment imposed at 4th to 6th weeks after emergence. among the stages, 4th to 6th weeks after emergence of soybean was found the most sensitive to salt stress in relation to seed yield reduction. the salt stress imposed at 6th to 8th weeks after emergence was also found damaging for seed yield production. introduction soil salinity and water stresses are the dominant abiotic stresses that limiting crop production after t. aman rice in the southern region. soybean (glycine max l.) is one of the most economic and nutritious crop in the world with high protein content (mondal et al., 2002). in bangladesh it is mostly used as poultry and fish feed. with the expanding of poultry and fish industries the demand of soybean has been increased manifold. to meet the demand a huge quantity of soybean is importing every year at the cost of substantial amount of hard currency. the cultivation area of soybean has also been increased simultaneously. however, the soybean cultivation is mostly concentrated in the coastal southern area, specifically in the greater noakhali district. the coverage area is increasing day by day and in the year of 2013 it reached above to an area of 61,000 ha (chowdhury et al., 2014).this crop is often grown after t. aman and the sowing of seeds is made by midjanuary. since, the soybean seed sowing is done in late rabi season near the coastal belt, the crop often exposed to soil salinity and water stress at the terminal stages of crop, and these stresses become severe at particular post flowering growth stages. under both saline and water shortage conditions, the plants face difficulty in smooth uptake of water for the decreasing soil osmotic potential. plants are unable to maintain metabolic activities, especially the turgidity of cell for normal growth under salt or water stress conditions, and that finally resulted yield reduction (khan et al., 2016). salinity or water shortage decreased pod number in pea (duzdemir et al., mailto:shawquatshahadat@yahoo.com 22 khan et al. 2009) and soybean (chowdhury et al., 2015). soybean is classified as a moderately salt sensitive crop (katerji et al., 2003) and denoted as sensitive to drought stress, especially at the early reproductive stage (westgate and peterson, 1993). despite a large number of studies conducted on the soybean response to salinity and water stress (khan et al., 2016; katerji et al., 2003; westgate and peterson, 1993), the dry matter production and yield response of the crop to salt or water stress imposed at different post-flowering growth stages are scarcely studied. therefore, this study was initiated to find out the sensitivity of different post-flowering growth stages of soybean to salinity and water stresses. materials and methods the experiment was conducted in a polythene house of the agronomy division at bangladesh agricultural research institute (bari), joydebpur, gazipur during rabi season of 2015. soybean var. bari soybean-6 was used for testing salt and water stress tolerance at different post flowering growth stages. seeds were washed several times with tap water for surface cleaning and then sown in soil medium on 26 january 2015 in plastic pots having 30 cm in height and 24 cm inner diameter. each pot contained 12 kg air dried sandy loam soil. chemical fertilizers of 0.30 g urea, 0.90 g tsp, 0.60 g mop and 0.60 g gypsum per pot were also incorporated into the soil before sowing. the pots were watered daily for easy germination. soybean plants were emerged on 01 february, 2015. after the emergence and establishment, two uniform healthy seedlings per pot were allowed to grow for four weeks (28 dae) in equal environment. after four weeks of emergence, all the growing plants in pots were imposed to the treatments. the treatments were; (t1) control, (t2) salt stress as irrigated the plants with 100 mm nacl solution at 4 th to 6th weeks after emergence, (t3) water shortage (irrigated with 70% depletion of available soil water when wilting sign developed) at 4th to 6th weeks after emergence, (t4) salt stress as irrigated with 100 mm nacl at 6 th to 8th weeks after emergence, (t5) water shortage at 6th to 8th weeks after emergence, (t6) salt stress as irrigated with 100 m m nacl at 8th to 10th weeks after emergence, (t7) water shortage at 8th to 10th weeks after emergence, (t8) salt stress as irrigated with 100 mm nacl at 10th to 12th weeks after emergence and (t9) water shortage at 10th to 12th weeks after emergence. the control group of plants was irrigated with tap water only. to induce salt stress, the pots were irrigated five times with 500 ml salt solution for 14 days by maintained an interval of two days. the experiment was arranged in completely randomized design (crd) with 8 replications. admire 200sl @ 1 ml/liter of water was sprayed at 10 and 25 dae to control jassids and white flies. ripcord 10 ec @ 1 ml/liter of water was sprayed at 45 and 60 dae to control leaf roller and pod borer. after the completion of the treatments imposition plant samples were collected from 4 replications and remaining 4 were allowed to grow up to maturity with irrigated fresh water. shoot and root parts of the collected plant samples were separated and then oven dried at 70ºc for 4 days to measure the dry weight. yield and yield contributing characters of the soybean plants under different treatments were recorded from the remaining pots after maturity. data were analyzed by mstat-c program and the treatment means were compared by using least significant difference (lsd). results and discussion shoot and root dry weight shoot dry weight of soybean plants was remarkably reduced by salinity and water stress at different post flowering growth stages (fig. 1). when the salt and water 23 dry matter production and seed yield of soybean as affected by post-flowering salinity and water stress stress applied during at the 4th to 6th weeks after emergence, the shoot dry weight under salt stress (3.97 g plant-1) and water stress (3.76 g plant-1) differed noticeably from the control treatment (4.34 g plant-1). shoot dry weight under salt (7.36 g plant1) and water stress (7.24 g plant-1) was identical but significantly differed from the control (11.98 g plant-1) at 6th to 8th weeks after emergence. similar result was also observed at 8th to 10th weeks after emergence. significantly the lowest shoot dry weight (12.06 g plant-1) was recorded from water stress when salt and water stress imposed during 10th to 12th weeks after emergence. shoot dry weight under salt stress (17.90 g plant-1) was identical with control (20.10 g plant-1) during 10th to 12th weeks after emergence. shoot dry weight of soybean was affected more in water stress than salt water stress at all post flowering stages. application of salt water increased soil salinity; at a given level reduced the soil water potential but probably did not reduce water flow to the roots. root cortical cells can osmotically adjust to some extent allowing water to move into the root. therefore, shoot dry weight of soybean was presumably affected more in water stress than salt water stress condition. fig.1. dry matter production in root and shoot at different post flowering stages of soybean under salt and water stress condition. the finding is in agreement with that of meiri (1984) that the metric potential preferentially affected the shoot growth of bean more than did the osmotic potential. similar result was also reported by khan et al. (2016) in soybean. shoot dry weight was found more sensitive to salt and water stress than root dry weight at all post flowering growth stages (fig. 1). root dry weight slightly decreased under salt and water stress at all the growth stages. the reduction in root dry weight of soybean due to salt and water stress was also reported by khan et al. (2014). under salt and water stress conditions, cell expansion is reduced due to low turgor, resulting in growth reduction. among the stresses, root dry weight decreased more in salt stress than water stress at 4th to 6th weeks, 6th to 8th weeks and 8th to 10th weeks after emergence. it might be due to sodium ionic damage on cell membrane and organelles. however, at 10th to 12th weeks after emergence, root dry weight decreased 4th to 6th weeks after emergence 6th to 8th weeks after emergence 8th to 10th week after emergence 10th to 12th week after 24 khan et al. more in water stress treatment (2.62 g plant-1) than salt stress treatment (3.01g plant1). the response was probably due to translocation of food reserve to the sink at seed production stage. chowdhury et al. (2015) also reported more reduction in root dry weight in soybean genotypes at pod filling stage as compared to vegetative stage under water stress condition. relative shoot and root dry weight the relative shoot and root dry weight drastically reduced under salt and water stresses imposed at all the post flowering growth stages (fig. 2). relative shoot dry weight significantly differed from control when salt and water stress were imposed. the highest relative shoot dry weight (91.47%) recorded from the salt stress imposed during 4th to 6th weeks after emergence which was identical with water stress at the same growth period (86.64%) and salt stress during 10th to 12th weeks after emergence (89.05%). the lowest relative shoot dry weight recorded from the water stress treatment (59.90%) during 10th to 12th weeks after emergence. relative root dry weight significantly differed from control when salt and water stress imposed at the post flowering growth stages. the highest relative root dry weight (95.58%) was recorded from water stress during 4th to 6th (s1) weeks after emergence, which was identical with salt stress at the same period (93.37%). the lowest relative root dry weight was recorded from water stress (69.87%) at 10th to 12th weeks after emergence. the reduction in relative shoot and root dry weight might be due to water shortage and sodium ionic damage. khan et al. (2014) also reported that relative shoot and root dry weight decreased significantly in soybean genotype under salt and water stress condition due to water shortage and sodium ionic damage. here, s1= 4th to 6th weeks after emergence, s2= 6th to 8th weeks after emergence, s3= 8th to 10th weeks after emergence and s4= 10th to 12th weeks after emergence. fig. 2. changes of root and shoot dry matter production at different post flowering stages of soybean under salt and water stress condition. yield attributes and yield yield contributing characters and seed yield of soybean plant under salt and water stress are presented in table 1. salt stress and water stress imposed at the post flowering growth stages significantly reduced number of filled pods, 100-seed weight, seed yield and days to maturity. the highest number of filled pods was obtained from control (53 plant-1) which was identical with water stress imposed during 6th to 8th (49 plant-1) and 8th to 10th (48 plant-1) weeks after emergence, and salt stress during 10th to 12th weeks after emergence (49 plant-1). the least number of pods was recorded from salt stress imposed at the post flowering growth stage of 4th to 6th weeks after 25 dry matter production and seed yield of soybean as affected by post-flowering salinity and water stress emergence (4 plant-1). number of unfilled pod was significantly differed between the salt stress and water stress treatments. the highest number of unfilled pod (16 plant-1) was recorded from water stress treatment of 10th to 12th weeks after emergence and the lowest recorded from salt stress during 8th to 10th (4 plant-1) weeks after emergence. table 1. yield contributing characters and seed yield of soybean under salt and water stress at different post-flowering growth stages treatment filled pods plant-1 (no.) unfilled pods plant-1 (no.) 100 seed weight (g) seed yield (g plant-1) days to maturity yield reduction (%) control 53.0 10.0 10.62 10.47 111 salt stress at s1 3.7 6.3 5.77 0.69 92 93.41 water stress s1 42.0 8.0 10.52 7.81 109 25.41 salt stress at s2 39.7 13.7 7.95 5.35 94 48.90 water stress at s2 49.3 8.0 9.74 7.48 108 28.56 salt stress at s3 43.0 4.3 7.79 7.75 95 25.98 water stress at s3 47.7 7.0 8.97 7.55 106 27.89 salt stress at s4 48.7 11.3 8.49 8.68 100 17.10 water stress at s4 45.0 16.0 7.29 8.09 103 22.73 lsd (0.01) 7.12 4.52 0.88 1.26 2.44 cv (%) 9.95 17.78 5.92 10.29 1.38 here, s1= 4th to 6th weeks after emergence, s2= 6th to 8th weeks after emergence, s3= 8th to 10th weeks after emergence and s4= 10th to 12th weeks after emergence. yield reduction of the respective treatments was measured as compared to the yield of the control treatment. it is well known that plants are unable to uptake water freely either in saline or water stress conditions due to decreasing osmotic potential of soil. water stress possibly reduced pollen fertility, increased pod abortion and reduced pod filling in soybean that resulted in decreased number of filled pods (khan et al., 2016; duzdemir et al., 2009). the maximum 100-seed weight of 10.62 g was obtained from control which was identical to water stress during 4th to 6th weeks after emergence (10.52 g) and 6th to 8th weeks after emergence (9.74 g). the lowest seed weight of 5.77 g was obtained from salt stress imposed during 4th to 6th weeks after emergence. salinity and water stress enhanced pod maturity that shortened the pod development period resulted in shriveled grain (ghassemigolezani et al., 2009; mannan et al., 2013; khan et al., 2016).the maximum seed yield of 10.47 g plant1 was obtained from control followed by seed yield under salt stress imposed during 10th to 12th weeks after emergence (8.68 g plant-1). the lowest seed yield of 0.69 g plant-1 was obtained from salt stress imposed at 4th to 6th weeks after emergence. the findings may be ascribed due to the fact that salt residual effect was prevailing in the soil from flowering to maturity and the plants had to uptake toxic sodium for longer period. the reduction in seed yield may be due to an increased uptake of toxic sodium that accumulated in cells and become toxic to the plant. nacl readily dissolved in water solvent yielded toxic na+ that may absorbed into root tissues and transport throughout plant organs, leading to toxic ion damage, osmotic stress and nutritional imbalance (cha-um et al., 2007; siringam et al., 2009) resulting low seed yield. the control plant took maximum days to maturity (111 days) which was followed by the plant under water stress imposed during 4th to 6th (109 days). the 26 khan et al. plant under salt stress imposed during 4th to 6th weeks after emergence took minimum days to maturity (92 days). the minimum yield reduction was observed when salt stress was imposed during 10th to 12th weeks after emergence (17.10%) which was followed by water stress treatment (22.73%) at the same stage of growth. the highest seed yield reduction was recorded in salt stress treatment imposed during 4th to 6th after emergence (93.41%) followed by salt stress imposed during 6th to 8th weeks after emergence (48.90%). the minimum reduction in seed yield at the later stage of growth might be due to pod setting and filling before water shortage happened due to salt and water stresses. conclusion from the above findings, it may be concluded that 4th to 6th weeks after emergence of soybean was the most sensitive postflowering growth stage to salt for seed yield. the salt stress imposed during 6th to 8th weeks after emergence was also much damaging for seed yield of soybean. seed yield reduction was minimum both in salt and water stress treatments imposed during 10th to 12th weeks after emergence. references cha-um, s., p. vejchasarn and c. kirdmanee. 2007. an effective defensive response in thai aromatic rice varieties (oryza sativa l. spp. indica) to salinity. j. crop sci. biotechnol. 10: 257-264. chowdhury, j. a., m. a. karim, q. a. khaliq, a. r. m. solaiman and j. u. ahmed. 2015. genotypic variations in growth, yield and yield components of soybean genotypes under drought stress conditions. bangladesh j. agril. res. 40(4): 537550. chowdhury, m. m. u., i. s. farhad, s. k. bhowal, s. k. bhowmik, and a. k. choudhury. 2014. fertilizer management for maximizing soybean (glycine max l.) production in charlands of bangladesh. the agriculturists 12(2): 98-102. duzdemir, o., a. kurunc and a. unlukara. 2009. response of pea (pisum sativum) to salinity and irrigation water regime. bulgarian j. agril. sci. 15(5): 400-409. ghassemi-golezani, k. m. taifeh-noori, s. oustan and m. moghaddam. 2009. response of soybean cultivars to salinity stress. j. food agric. environ. 7(2): 401-404. katerji, n., j. w. van hoorn, a. hamdy and m. mastrorilli. 2003. salinity effect on crop development and yield, analysis of salt tolerance according to several classification methods. agric. water manage.. 62: 37-66. khan, m. s. a., m. a. karim and m. m. haque. 2014. genotypic differences in growth and ions accumulation in soybean under nacl salinity and water stress conditions. bangladesh agron j. 17(1): 47-57 khan, m. s. a., m. a. karim, m. m. haque, m. m. islam, a. j. m. s. karim and m. a. k. mian. 2016. influence of salt and water stress on growth and yield of soybean genotypes. pertanika j. trop. agric. sci. 39(2): 167-180. mannan, m. a., m. a. karim, m. m. haque, q. a. khaliq, h. higuchi and e. nawata. 2013. response of soybean to salinity: ii. growth and yield of some selected genotypes. trop. agr. develop. vol. 57(1): 31-40. meiri, a. 1984. plant response to salinity: experimental methodology and application to the field. in: i. shainberg and j. shalhevet (eds.) soil salinity under irrigation. springer verlag, new york. pp. 284-297. 27 dry matter production and seed yield of soybean as affected by post-flowering salinity and water stress mondal, m. r. i., m. a. wahab, m. s. alam, m. m. u. ahmed and f. begum. 2002. leaflet of bari soybean 5. orc, bari, joyderbpur, gazipur. siringam, k., n. juntawong, s. cha-um and c. kirdmanee. 2009. relationships between sodium ion accumulation and physiological characteristics in rice (oryza sativa l. spp. indica) seedlings grown under iso-osmotic salinity stress. pak. j. bot. 41: 1837-1850. westgate, m. e., and c. m. peterson. 1993. flower and pod development in water– deficient soybean (glycine max l. merr.). j. exp. bot. 44: 109-117. microsoft word final.doc � �������� ��� �������������������������� ��� !�"�#$��! �%&��'�(!)�*��%���+�,�&-'.�'��#%�+�#'�*���� !�"�#$��! �%&��'�(!)�*��%���+�,�&-'.�'��#%�+�#'�*���� !�"�#$��! �%&��'�(!)�*��%���+�,�&-'.�'��#%�+�#'�*���� !�"�#$��! �%&��'�(!)�*��%���+�,�&-'.�'��#%�+�#'�*� �"�#��-$��)#*�����-# �*��$!%,%'�"�-#�%,+.�'���(-!#�"�#��-$��)#*�����-# �*��$!%,%'�"�-#�%,+.�'���(-!#�"�#��-$��)#*�����-# �*��$!%,%'�"�-#�%,+.�'���(-!#�"�#��-$��)#*�����-# �*��$!%,%'�"�-#�%,+.�'���(-!#���� ���� "��-��#�/ 0�"��-��#�/ 0�"��-��#�/ 0�"��-��#�/ 0�������������"�����% � �1����"�����% � �1����"�����% � �1����"�����% � �1�������� %%!��! �*�����-��%2� �3������ $� � 4�����5���03 � ��678��/ 0�92� ���5�6�������� :�2;� � �:�2;� � �:�2;� � �:�2;� � ������2�5 �447���� ����5 �447����4 ��0537<732��4 �=73�17�732�� ;��3���0 �� ���� �1 3 �53��1 3 �53��1 3 �53��1 3 �53����� ���� ' 7 � 30�2�;� �5� 7����03� 3���<��0�3�� 3 ���5���675�1���=73 ��=� ;��3���0 �� ���2�;73 � 3 �� 4���3����6��� 75��0��� � =� 6� > � =7����5���737����3� � 67���%2 3�6��� �� 5 ����� *�<���46��3� � %�*�� 73��� �����40 � ����"0�37� +�5�37��� '� 37��� �"+'�� 73��� ?�@7���a� �=� %2� �3� ��7��� �0 7������������� ���������������' �� 3 ��36��3� 5�617��37�� �'���'�� �6��� 75��b� ;��3���0 ���<� ��"���7@����'���'���6��� 75��b� ;��3���0 ���<� ��.�37 4� ��� ��5����'���%;��3���0 ���<� ��"���7@��� �����'���%;��3���0 ���<� ��.�37 4� ��� ��������'��� '�� �6��� 75�� ���� �<� �� �7��� ������ ;� � 6�7�3�7����� ' �� 30�2� ;� � 1� ��� 7�� �� ����67/���5�64��3��1��5@���$����� 7���;73 � 7c��7 4� ��� �4�75�37�� ���� 0�3 �7��3� 6 � �=�3 ��5 �4 �27����� 75���d07<����3�27������ � � �30 ��������3� �30 ��;73 �1���=73�5� 3� �37�� �;��� 7� � �7�� ;��3���0 ��b�3 �� 4���3����6��� 75�� ���2�5 �447��� 2 3�6��%��� ;��3� ��0 ��� ���2���;73 ��3 �� 4���3����6��� 75��5�0���1������5���675���2�<7�1���3�5 �����2�� 7� 3�����=� ����5 �447����=� ��1� 3�037�7/�37����=�=����;������;73 � � 7�0��� �7��6�7 30 ��7�� %2� �3� ��7����� ���� -�3 ��0537��-�3 ��0537��-�3 ��0537��-�3 ��0537������ ���� ' ��<� 3�� �� ��=�%0 6��:0 72� �� ��������7�� �7��7��%2� �3� ��7����=���?����� �6�7��=����;�7�� ��5 �2�� ��0 7��� �17� �� ����0��3����5@��=�7 7��37���=�57�737� ���%�7��6�7 30 ����� ���;��d075@�2� �=3� � � <� 3��=�'���6��� 75������5�� �d0��3�2�3 ������� �6�7� �=����;�=� ��� 01 3��37���4� 7����=� �1�03�����6��3 �� �#�/ 0���3������������� -3� 7 ������� ���4 �5375���=�3 ��=� 6� �3��� �;�<� 7�0 � ;7�3� �5 �4 �7��3 ��=7�����=3� �3 �� � <� 3��=�3 �� 4���3����6��� 75��3 �0� �3 �� � 7�0���6�7 30 �� 7 �7����d0�3��=� �4 �4� �� �;3 ��=�3 ��4���3 ��' �� ���2�5 �447���;73 ��3 � �5 �4 ��7@����3 2 0 �� �4� �����60 3� ���4�3�3�������3 � �<���3�1�� �� ��4 �<7�7���6� �� �60�� �37���3��3 ��=� 6� � 7� 3���� �=� ���� 5 �4 � �(043�� ���� � �;675@�� ������� -3� 7 � �� �� �� 0 7��� 3 �� �� 67��37��� 12� 037�7/7���3 ���c7 37��� � 7�0��� �7��6�7 30 ������3���<�7��37�������4� �37�� ��0 7���5 �4�� �;7����-3� � 06�� 3 �3� 05 � ���2� 5 �447��� 2 3�6� 5��� 7�5 �� �� 3 �� 043�@�� ���� 0 �� �==757��52� �=� 7�403 � 1�5�0 �� �=� � �;7��� �=� 3;�� 5 �4 � 7�� � �7==� ��3� 376� �� %;��3� ��0 �� �$050 173�� 6� 5 �3��� 7 � �� 4 �67 7��� <���3�1��� 7�� �������� � ; 75 � 5��� 1�� � �;�� 7�� ;����� �7���� =� 37��� �7� � ;73 � 4.� 1�3;����e��� ����e���� ' �� 4064@7�� � � �� 7� � 5��3��3� �=� <73�67��*� � �;���� � �67�� �� � �7@�� 5�44� �� 7 �������4 � 4 � 0 �� ����;�'�� �0 �'���6��� 75�� 7 � 3 ����67���3� 5 �447���4�33� �� 7�� 3 7 � ��7��� 0��� � �7�=��� 5���737��� 7�� 6��706� 7� ����� 3�� ��;����� � �� � �=� %0 6��:0 2� �� ����4��7���'�� �0 � 75�� 7 � 1�7�����4��������� �7�=���� ����0 0���2� 3 �� 4���37��� 7 � ����� 7�� �� �2� "�2��' 7 �����2���3 �� 4���3�37����=��0 � 75��� �64� ���3 ��376��2�50�37<�37����=� 01 �d0��3�'�� �6��� 75������ � 0�37�������2� �;7����=� �17�5 �4 ��-��%2� �3��=� 6� �=�57���4 �1��6 �;73 �3 �� 50�37<�37����=� ;��3���0 ��� 4�57���2�����2��� �;7����=� ��� �� ����7�� �� 3�1�7 6��3�7��3 ��=7���� ������5@��=�7 7��37���=�57�737� ��35��-3�7 ���3���3 �3�3 � ��'���6��� 75��50�37<�3���� �� �7��6��706� 7� �����5���1���� 7�2�1 �0� 3�0��� � ���2�50�37<�37���;73 � ;��3���0 ��;73 �67�7606�6�7 30 �� � 0�37��� 7�� 7�5 �� �� �=� 3�3��� 4 ��0537<732� ;73 � 67�7606� 5� 3�� %��� 3 � �� 7 � ��� �44� 30�732� 3�� �f� #�/ 0���3����� 50�37<�3�� ;��3���0 ��� � ���2�5 �4� 7��'���6��� 75�� =7�����&73 � 3 7 �<7�;�� 3 ��4 � ��3� 30�2� � � 1������ 7����� 3�� �<��0�3�� 3 �� �5���675� 1���=73 � �=� ;��3� ��0 �� ���2�;73 � 3 �� 4���3��� �6��� 75��0��� ���?����7��%2� �3� ��7���� ���� "�3� 7�� �����"�3 �� "�3� 7�� �����"�3 �� "�3� 7�� �����"�3 �� "�3� 7�� �����"�3 �� ���� ���� ' 7 ��c4� 76��3�;� �5� 7����03�0��� �=� 6� > �=7����5���737�� ��3� � 67���%2 3�6��� �� 5 ����� *�<���46��3� � %�*�� 73��� �����40 � ���� "0�37� +�5�37��� '� 37��� �"+'�� 73��� ?�@7���a� �=� %2� �3� ��7����0 7����������������������������' �� 3 ��36��3� 5�617��37�� �;� �� � �'���'���6��� 75�b ;��3���0 �� �<� ��"���7@����'���'���6��� 75�b ;��3���0 �� �<� ��.�37 4� ��� ��5����'���%;��3� ��0 �� �<� ��"���7@��� �����'���%;��3���0 �� �<� ��.�37 4� ��� ��������'���'���6��� 75�� ���� �<� �� �7��� ������� ' �� 30�2� ;� � 1� ��� 7�� �� ����67/��� 5�64��3�� 1��5@� ��$��� �� 7��� ;73 � 7c� �7 4� ��� �4�75�37�� ��' �� ����7�� � �=� '�� �6��� 75��;� �� 3 �� 4���3��� ����������0�0 3� ���� � <� 3��� ��� ������ #�<�61� � 7�� ��5 � 2�� �� "��3 �2� �<� ���� 6�c7606� ���� 67�7606� 3�64� �30 � ����� �7�=������3��� ��4 � ��3����7�� 7������' �� ;��3���0 �� ��� �;� �� �;�������� ��2 �1�=� �� � <� 3��=�'���6��� 75��12�6�@7��� ��4�5������g"���>�;73 �6�7�3�7�7���3 ���7 3��5�� 7 ���6�h���6��' ���3��=7<�� ��� ��=� ;��3���0 ���=���5 �<� 7�32�;� �� �;��7����5 �"����� � ���2� ����f�!53�1� �3����#�<�61� �7��'���6��� 75��=7�����; 7��� ;��3���0 �� ����;� � �;���������f� #�<�61� ��=3� � � <� 3��=�'���6��� 75���' �� 7/���=� 3 ��"����;� ����56�c����56� h����56�� � 37�7/� � ;� �� �44�7��� 9� f���������f����� ���� ���������������� :�� ���� �=� #�:%?��� =� � ;��3���0 ������'���6��� 75��7��3 ��=� 6��=�) ����'%���"����(24 06��?7�5� 0�4 �3�������� 75� �57��� � 4�537<��2� � �(�� ������� $�;� �0��� �� 3� ���� ;� � �44�7��� =� � ;��3� ��0 ���"�3 �� � �=� =� 37�7/� � �44�75�37��� ;� �� 6�7�3�7���� � � 4� � �(� ������� ���� "������ �3� ���� �������� ' �� �c� 4 � �6����3 �4�������;73 �4�7 ���1�73�;� �0 ���=� �5��3 ���7���3 ��= 073�=�2��"���3 7������$�9� �6�b+�����'7�3�����$�9��6�b+�;� ���44�7����3����7�3� <����=�������2 �=� �5��3 ���7���1��3������� 4�;�� 2�67���;�� � 4�537<��2���44 �c76�3��f�����73� ��=�;�3� �4� �473�3;75����;��@�12�;�3� 7��� ;� �6�7�3�7����3���� 0 ��1�33� �� �;3 �����= 0737����=�4064@7���.����4���7��37���;� ������7�� �6��5� � � =� �6� ��= 0737����' �� ;��3���0 � �;� �� � <� 3���= �6���� �1 0� 2�3������4 7��� ,7�����=�7��7<7�0���5 �4�;� �5��<� 3���7�3���d07<����3�27�������3 ��1� 7 ��=�3 ��4 �<�7�7���6� @�3� 4 75���=�7��7<7�0���5 �4��%7�� ��3�������ii�j�����2���������7���ii����� � �75���d07<����3�27�����3 �����k�, �l��,7 �h�� �b� � � & � ��� , �k�,7�����=� ����3 �� 4���3����6��� 75���3� ����� ,7 �k�,7�����=� ;��3���0 ��� � ���2��3� ������ � �k�%���7���4 75���=� 75����� � �k�%���7���4 75���=� ;��3���0 ��� � ' �� �7��6�7 30 ��;� �6��73� ���12�� �<76�3 75���3� 67��37���7�������2�7�3� <�� ��3�����56���� ���56�������56�����������56���43 ��' �� �7�� �64�� �;� ��5����53���;73 ��� 5 �;��0�0 �= �6� 3 �� �c4� 76��3��� 4��3 � ���� 403� 7�� ��067�06�504 � ���� �=3� � 3�@7��� = � �;�7� 3�� �64�� �;� �� @�43� 7�� 3���� 3 � 6�� 3�37 375���2� 5��3 �������<��� =� �� 27�����3� ��� 3���� �64�� �;� ��5����53��� = �6���5 � 4�3 ������<� ��� ��=� 3 � ��;� ��0 ����' �� �7��6�7 30 ��5��3��3�;� �6�� 0 ���12� =����;7���� �<76�3 75�6�3 �������5@���ie���� ' �� �5� ���� ��3�� ;� �� 3�37 375���2� ����2/��� ���� 6���� <��0� � ;� �� �4� �3��� 12� +%*� 3� 3� =����;7���(�6�/� ����(�6�/� ��if�������� 324� ��=� 5� 3 � �=� 4 ��0537���;� �� �5� ���� ���� 5� 3� 1���=73�����2 7 �;73 � � 4�53�3����3� �30 ��;� �5� 7����03�3���<��0�3��3 ��4 �=73�17�732��=��7==� ��3� ���2�5 �447���3 ��36��3�5�617��37�� ��� �i� %;��3�(�0 ��� �����2�;73 �' �� 4���3����6����75��� �� 0�3 �����*7 50 7���� 0�3 �����*7 50 7���� 0�3 �����*7 50 7���� 0�3 �����*7 50 7������ ���� ' ��3;��2�� ��<� ����27�����=� ;��3���0 ������ 75��� �7���3�"+'� 73���?�@7���a����� %�*� 73��� �����40 � ��5�37�� � � � 1���� �;�� 7�� '�1��� �� m� ��� � 4�537<��2�� ' ��� 2�� � ������������ �<� ����6�c7606�����67�7606�3�64� �30 ������3�3��� �7�=����7��%2� �3�� ��4 � ��3���7�� 7����� �6�3 ��� �4 �73�;� ��1 � <���3 �3�3 ���<� ����6�c7606�����67�7606�3�64� �30 � �;� ��7�� 3 ��6��3 ��=�!53�1� ��������0� 2�� � 4�537<��2��' ��6�c7606� �7�=���� �5� ���� 7���0������� ��6� 3� ��� �7�=���� ;� � =�0��� 7�� ���0� 2� 3�� �1 0� 2� ; 7��� 7��#�<�61� � 3��*�5�61� �� �� <� 2� 6���� �6�0�3��=�4 �57473�37����1 � <����6�0�37��� a0 3�1���;����66��.�;�<� �� 7�� � 3��=� 3 �� 6��3 � 3�3��� �7�=���� ;� � ������ = �6� ����66� 3�� a0 3� 1���;� f���66��*0 7��� 3 �� 4� 7��� �=� �c4� 76��3 �� 3�1�7 6��3� �;����� �47����5 �� ��7�� �7��6�7 30 ���3�3 �� �5���������56���43 � 3 �0� �3 ��7�737���6�7 30 ����<���;� � 7� ��f��in�� 7������1���' ��7�737��� �7��6�7 30 �� �;����� 7� ���<���7��������2� �04�3��3 ��=7 3�=�;�;��@ ��=�#�<�61� �7����5 �2�� ��103���5 �� ��;73 �3 �� 7�5 �� 7��� �=� 376��� ' �� 6�7 30 �� 5��3��3 � �=� ������ 56� ���� ������ 56� ��2� � �7�� ��3� �;� �44 �57�1���<� 7�37�� �; ���5�64� ���3��3 ��3�4���2� �7��1�3 �3 ��2�� �� 7������1��� � '�1��� ���( �7�� 27���� �=� '�� �6��� 75�� ���� ;��3� ��0 �� 7�� ���2� 5 �447��� 2 3�6� �3�"+'� 73��� ?�@7���a����������� ' ��36��3 � ?�@7���a� �75���d07<����3�� 27�����3� �����%;��3���0 ���3� ����� '���6��� 75���3� ����� �������� �������� �<� ���� �������� �������� �<� ����� � '�� ����e� ������ �i���� ��ei� ���i� ����� �f���� '�� ����i� ���f�� ����e� ����� ��fe� ��f�� �f�f�� '�� �e��e� ������ ���f�� �� �� �� ������ '�� �f���� ������ �e�ff� �� �� �� ���ee� '�� �� �� �� ��ff� ��i�� ��i�� ��i�� +%*�����n�� ��i�� ����� ����� ����� ����� ����� �� $o��n�� e���� ��ff� ���i� ����� ����� ��fi� �� '���'���6��� 75�b ;��3���0 ���<� ��"���7@����'���'���6��� 75�b ;��3���0 ���<� ��.�37 4� �����5����'���%;��3���0 ���<� �� "���7@��� �����'���%;��3���0 �� �<� ��.�37 4� ��� ��������'���'���6��� 75�� ���� �<� ���7��� ������� p� 75�� �'@��@������ �'�� �6�����e�������� ;��3���0 �������� � � '�1������( �7��27�����=�'���6��� 75������ ;��3���0 ��7�� ���2��=� ;��3���0 ��;73 �'���6��� 75�� 5 �447��� 2 3�6��3� %�*� 73��������40 ����������� ' ��36��3 � �����40 � �75���d07��27���� �3� �����%;��3���0 ���3� ����� '���6��� 75���3� ����� �������� �������� �<� ���� �������� �������� �<� ���� � '�� ������ �i���� ���if� ��e�� ����� ��ef� �i���� '�� ������ ������ ������ ����� ����� ����� ������ '�� �i���� ������ �f��e� �� �� �� ������ '�� �f���� ���fe� �e�if� �� �� �� ������ '�� �� �� �� ��i�� ��i�� ��i�� ��i�� +%*�����n�� ����� ���f� ��i�� ����� ����� ����� �� $o��n�� e���� ���i� ��i�� ���e� ����� ���e� �� '���'���6��� 75�b ;��3���0 ���<� ��"���7@����'���'���6��� 75�b ;��3���0 ���<� ��.�37 4� �����5����'���%;��3���0 ���<� �� "���7@��� �����'���%;��3���0 �� �<� ��.�37 4� ��� ��������'���'���6��� 75�� ���� �<� ���7��� ������ pp� 75���=��03403� �'@������ @�������'���6��� 75����e�������� ;��3���0 �������� ��� #�/ 0���3����� �������� ���� ��� ���� � ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� �� ��� ��� �� ��� !"� # $ %�" &�'������())* � � �� �� �� �� �� �� +�)�, (%� ,�-,* + ����&�'����� ��.�+�)�, �'��+�)�, � 7��� ��� ���0��� 6��3 �2� 3�3��� �7�=���� �66�� ���� 3�64� �30 �� �0 7��� 3 �� 4� 7��� ����������7��%2� �3� � � ���� 7��� ���� ' �� 7�737��� �7��6�7 30 �� 4� 5��3� �3� =�0 � �7==� ��3� ��<�� � �=� ��43 � �=� 3 �� �c4� 76��3��� 73���0 7���!53�1� �3��#�<�61� ������� � ��� %;��3�(�0 ��� �����2�;73 �' �� 4���3����6����75��� ���� 7��� �1�� ' �� 7�737��� �7��6�7 30 �� 4� 5��3� �3� =�0 � �7==� ��3� ��<�� � �=� ��43 � �=� 3 �� �c4� 76��3��� 73���0 7���!53�1� �3��#�<�61� ������� �� � +�5�37����"+'�%73���?�@7���a+�5�37����"+'�%73���?�@7���a+�5�37����"+'�%73���?�@7���a+�5�37����"+'�%73���?�@7���a���� -3�;� ��1 � <���3 �3� 3�37 375���2��7==� ��3�27��� ��=� ;��3���0 ������'���6��� 75��;� ��=�0��� 7�� 1�3 �2�� ��' ���<� ���� 7� � �= 073�27�����=� ;��3���0 �������e�3� �����;� � �5� ����7��'���'�� �6��� 75�b ;��3� ��0 �� �<� �� .�37 4� �� ��5���� =����;��� 12� '�� �'�� �6��� 75�b ;��3� ��0 �� <� �� "���7@����; 7��� 3 �� ��;� 3� 27���� ����f�� 3� ����� 7��5� ���=� 21 7��<� 7�32� �"���7@���� ��� ����5 �4�� ��3;����3 ��3;��3� 3��� ;��3���0 ��<� 7�37� ����5��������.�37 4� ���4 ��05��� 7� � �= 073�27����7�� 1�3 � ���� ���� ���2� 50�37<�37���;73 �'�� �6��� 75���' 7 � � 0�3� 7��75�3��� 3 �3� 3 �� ��5��� <� 7�32� 7 � 6� �����43���� ��55�76�37/��� 3 ��� 3 �3��=� 21 7��<� 7�32� �"���7@��� 7��?�@7���a� ��5�37����!�� 3 �� 5��3 � 2��3 �� 7� � �� �7��27�����=�'���6��� 75��;� � �5� ����= �6� 75��� � ����5 �4�7��1�3 �3 �� 2�� ��-��5� ���=� ���2�5 �447�����733����� �27�����=�'���6��� 75��67� 3�1���0��3�� 7���67 7����0 7��� 3 ��4 �4� �37����=�473 �=� � ;��3���0 ���.�;�<� ��3 �� 7� � 3� 75���d07<����3�27������f�f��3� ����� ;� � �5� ���� 7�� '�� =����;��� 12� '�� ��f���� 3� ������ %;��3� ��0 �� 4� =� 6��� 1�33� � 3 ��� ���� 5 �447��� 2 3�6�� -3�67� 3� 1�� �0�� 3�� �� �2� �;7��� �=� ;��3� ��0 �� � � ���2�;73 � '�� �6��� 75��� ; 75 �4 �<7����<� 2�5�����7���675 �5�76�3��;73 �037�7/7���4 �������� � 7�0��� �7��6�7 30 �� 3 ��� ��3�� �;7���� � +�5�37���� %�*� 73��������40 +�5�37���� %�*� 73��������40 +�5�37���� %�*� 73��������40 +�5�37���� %�*� 73��������40 ���� ' �� � 0�3 ��=�3;��5�� �5037<��2�� � �<����3 �3� ���2�5 �447��� 2 3�6�4 �<7����3 �� 7� � �= 073� 27�����=� ;��3���0 �� �3 � � 3 ��� ���� 5 �4��c5�43� 75���' ���<� ���� 7� � � = 073� 27�����=� ;��3� ��0 �� ������� 3� ����� ;� � 4 ��05��� 12� '�� �'�� �6��� 75�b ;��3� ��0 �� �<� �� .�37 4� �� ��5���� =����;���12�'���'���6��� 75�b ;��3���0 ��<� ��"���7@����; 7���3 ����;� 3�27������e�if�3� �����12� '���%;��3���0 ��<� ��.�37 4� ��� � ������-��3 �� ����5 �447��� 2 3�6 ��3 �� 21 7��<� 7�32�"���7@�� 4� =� 6��� 1�33� � ���� 4 ��05��� 7� � � = 073� 27���� ��f��e� 3� ����� 7�� �����40 �� ' 7 �67� 3� 1�� 3 �� �==�53��=��7==� ��3� �7������675 ��5�76�375�<� 7�37��� 7�� ��5�37���3�� ��5�37��� 7��%2� �3� ��7���� ��03� 3 �� ����5 �447��� 2 3�6��'����=�'���6��� 75��4 ��05��� 7� � �� �7��27��� �3 ��� ���2�7��1�3 �3 �� 2�� �������;73 ��<� ����27�����=���i��3� ���� �'�1�������!��3 ��5��3 � 2�� ���2�5 �447��� 2 3�6� ��� #�/ 0���3����� 4 ��05��� �7� 3�2��� �27�����=�'���6��� 75���-3�67� 3�1���0��3��3 ��� ���037�7/���=� �6�@7���473�� � 6���� =� � ���2� 50�37<�37��� �=� ;��3� ��0 ��� ' �� �<� ��� � �=� 75�� �d07<����3� 27���� ;� �� �� �� 6�c7606� 7�� '�� ��i���� 3� ������ <� 2� 5�� �� 3�� '�� ��f�f�� 3� ������.�;�<� �� 3 �� 7� � � 27���� �=� ;��3���0 �� 7�� ���2�67� 3�1���0�� 3�� 3 ��6�c7606�037�7/�37����=� �7��6�7 30 ��� �;���� � ��� �2� �;7����=� ����� � $� 3����� �30 ������2 7 $� 3����� �30 ������2 7 $� 3����� �30 ������2 7 $� 3����� �30 ������2 7 ���� $� 3� 1���=73� ����2 7 � �=� ;��3� ��0 �� ���2� ;73 � '�� �6��� 75�� ;� � 4 � ��3��� 7�� '�1��� ��� -3� 7 � �<������ 3 �3� 3 �� 7� � 3�� � � �30 �� �'@��������� ����� ������3� �30 �� �'@��f����� �����;� � �13�7����12�'���'���6��� 75�b ;��3���0 ��<� ��.�37 4� ����5����; 75 ��� ��4 �<7���� 7� � 3��$�� ��������=����;���12�'����������' 7 �<� 7�37����550 ����0��3��27��� ��7==� ��5� ��=� ;��3���0 ������ '���6��� 75���' ����;� 3�� � � �30 ���'@��e��e�� �����������3� �30 ���'@�����fi� ������ �;���� � ���;� ��$���������;� ���7����= �6�3 ��'���'���6��� 75��� � ������� � '�1�������75���d07<����3�27�����$� 3����� �30 ������2 7 ��=�3 ��36��3 � ;��3���0 ��;73 �'���6��� 75��� � ���2�5 �447��� 2 3�6�7��%2� �3����������� ' ��36��3 � �<� �����75�� �d0��,7���� �3� ����� ( � � �30 �� �'@�� ����� '�3���5� 3� �'@�� ����� #�3� �30 �� �'@�� ����� �$�� '���'���6��b ;��3���0 ��<� ��"���7@��� �f�f�� ����f�� �����e� �ee���� ����� '���'���6��b ;��3���0 ���<� �� .�37 4� ����5���� �i���� ������� ���ife� �f����� ����� '���%;��3���0 ��<� ��"���7@�� ����� ������ �ii���� ������� if��e� ��i�� '���%;��3���0 ��<� ��.�37 4� �� ����� ������ ������� i����� ��e�f�� ���i� '���'���6��� 75�� ����� ��i�� e��e�� ������ ���fi� ����� p� 75���=�7�403������03403��'@�@����� �'@b"b*�2���) �������'%������"�������4��0� 7���'@�����17� �������1�0 ������ ;��3���0 �� �������b����� 75�� ����������� 75������ ������e�������� ;��3���0 ���������4� 37 7������i����� � $��5�0 7��$��5�0 7��$��5�0 7��$��5�0 7������ ���� �6�3 ���1�<��=7��7���73�6�2�1��5��5�0�����3 �3�3 ��3 ��36��3�5�617��37���'���6��� 75�b ;��3� ��0 �� �<� �� .�37 4� �� ��5���� ���2� 4� =� 6��� 1�33� � ���� 4 ��05��� 6�c7606� �6�0�3� �=� 75�� �d07<����3�27����;73 � 7� � ��$�� ��������; 75 �;� � =����;���12�'�� �'���6��� 75�b ;��3���0 �� �<� ��"���7@�� 21 7�����$� 3�1���=73�����2 7 � �<������3 �3�3 �� 7� � 3�� � � �30 ���'@��������� �� ���������3� �30 ���'@��f����� �����;� ��13�7����12�'���'���6��� 75�b ;��3���0 ��<� ��.�37 4� �� ��5����� ' � �=� ��� 5�� 7�� 7��� 27����� � � � �30 �� ���� �$��� 3 �� ���2� 5 �447��� �=� ;��3� ��0 �� ;73 �'���6��� 75��;� �=�0���4 ��0537<������� �<7�1��� =� �037�7/7���=����;� ���� �0��� � 3 ��%0 6�� :0 72� �� ��������7�� �7��7��%2� �3� ��7���� ���� ��=� ��5� ��=� ��5� ��=� ��5� ��=� ��5� ���� ���� ���5@��$������ie���"�3 �� ��=�%�7������2 7 ���� 3�-�� 2 75�������67�� ����75���4 �4� 37� ���6� 75��� %�57�32��=��� ���62��"��7 ����&7 5�� 7���)%��� �(�� ������ � 37�7/� � ��5�66����37��� (07���� �������� � �� 750�30 ��� �� �� 5 � $�0�57�� ����$��� � 6��3���* �@�����������4�� (�6�/�:����� ����������(�6�/�� �if��� %3�37 375��� � �5��0 � � =� ��� 750�30 ��� �� �� 5 �� ���� ����� �� ��&7��2�����%�� ��#�;�,� @��4��i���� ��� %;��3�(�0 ��� �����2�;73 �' �� 4���3����6����75��� (043���%������"��:��� �;675@��������%5�4���=�� �;7�����3 2 0 ��������37��7�� ���2�5 �447��� 2 3�6 � �=3� � 75��7��&� 3���������-��7���+�3 2 0 �+�3 2 7 6�#�; ������� "�������"�����-���"��%����6��"��������� 072����"��"���� 6����"��%�����6�����"��.��.���� 6���� ������ : 7 7� � �a0@37� .�31�7� �.���1��@� ��� �� ��3�5 �����2��� �3 � ����� �������� � �� 750�30 ����� �� 5 �-� 37303���(�/740 ��������������� ��� #�/ 0���"��-��"�����% � �1�����:��$ �;� 0 2��������)��%� @� ��������%�7��"�7 30 ��"��73� 7���7��'�� �6����75��.� <� 3��� ����;�+����)��� �%0 6��:0 7� �� ��������7���=�%2� �3���������� � �� ��������e�������i�ee�� ����2��'��,������(��.��%������7���ii���� 7�574�� ��=��� ���62��:��2��7��01�7 � ��#�;�*�� 7����� �����-��7�������� %7�� ��$��o������:��%7�� �����o��%��$ �0 �����ii�������37<��4� =� 6��5���=�47�����4�������324��7�� �������� 75��7�3� 5 �4� 2 3�6 ��-�3����7����4���#�; ��������i����� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � genotypic differences in soybean in relation to growth and ions accumulation under nacl salinity and water stress conditions bangladesh agron. j. 2014, 17(1): 47-58 genotypic differences in growth and ions accumulation in soybean under nacl salinity and water stress conditions m. s. a. khan1, m. a. karim2 and m. m. haque2 1agronomy division, bari 2department of agronomy, bsmrau corresponding author: shawquatshahadat@yahoo.com key words: salt and water stress, dry matter production, ions accumulation abstract salt and water stress tolerance of the seven soybean genotypes viz. bari soybean 6, bd 2329, bd 2342, ags 95, bgh 02026, galarsum and bd 2331 were evaluated for their performance at 0 and 100 mm nacl under well watered & water stress (watering with 70% depletion of available water at wilting) conditions at the banghabandhu sheikh mujibur rahman agricultural university, salna, gazipur. the results indicated that all the growth parameters like plant height, shoot dry weight, root dry weight and dry matter distribution in different plant parts of the genotypes sharply decreased when the plants were exposed to water stress, salt stress and, combined salt and water stress conditions. among the genotypes reduction in dry matter production was the least in galarsum and bd 2331 in both the salt stress and, the combined salt and water stress conditions. these genotypes also accumulated lower amount of na+ and higher amount of k+ in leaf tissues under salt stress and, combined salt and water stress environments as compared to others. introduction soybean is classified as a moderately salt-tolerant crop and the yield will be reduced when soil salinity exceeds 5 ds m-1 (maas and hoffman, 1977). high levels of salts in the soil can often cause serious limitations to crop production. raptan et al. (2001) found that salinity decreased root, stem and leaf dry weights, and reduced plant height of mungbean plants. the adverse effect of salinity on plant is dependent on salt concentration in the substrate, duration of exposure to salinity and stages of plant growth (blum, 1988; maas and poss, 1989; gill, 1990). it is well known that salinity harms crop growth. plants under high saline conditions cannot always absorb sufficient water for metabolic activities or maintain turgidity because of the low osmotic potential in the growth media. at the same time, plants absorb damaging amounts of na and cl (blum, 1988; greenway and munns, 1980; karim et al., 1992). na+ is the primary cause of ion specific damage, resulting due to a range of disorders in enzyme activation and protein synthesis (tester and davenport, 2003). therefore, exclusion of na+ at root level and maintenance of high k+ at shoot level are vital for the plants to grow under saline conditions (munns et al., 2000; tester and davenport, 2003). it is very common in the arid and semi-arid regions that when the crop growth season progresses, the precipitation decreases, and temperature and evapo-transpiration increase, resulting in rising salt concentration in the soil solution (abdulrahman and williams, 1981). thus, salt and water stress prevails at the same time in the dry seasons, which very often add extra harm on plant growth (karim et al., 1993). normally, salinity stress produces high osmotic potential in the soil solution (hayward and spurr, 1943), whereas water stress impairs soil moisture transmission due to matric potential (gingrich and russell, 1957). however, the adverse effects of both salt and water stress are primarily due to the restriction of water uptake by the roots (karim et al., 1993). the response of soybean to salinity stress depends both on genotypes and environmental conditions (ghassemi-golezani et al., 2009). 48 khan et al. in the coastal area of bangladesh, soil salinity increases during dry period (march – may) due to lack of rainfall. thus, salinity and drought exist together during that particular period. it is well known that salinity exerts more deleterious effects on plant growth when drought prevails along with salinity. therefore, this study was undertaken to analyze the growth and mineral ions accumulation pattern in some soybean genotypes. materials and methods the experiment was conducted in a plastic house of the department of agronomy at banghabandhu sheikh mujibur rahman agricultural university (bsmrau), salna, gazipur, bangladesh. seven genotypes (bari soybean 6, bd 2329, bd 2342, ags 95, bgh 02026, galarsum and bd 2331) of soybean including barisoybean 6 were used for testing their salt and water stress tolerance. selected genotypes were denoted as moderately salt tolerant (khan, 2013). seeds were washed several times in the tap water for surface cleaning then sown in the soil medium on january 13, 2011 in plastic pots having 30 cm in height and 24 cm inner diameter. each pot contained 12 kg air dried sandy loam soil. chemical fertilizers of 0.30 g urea, 0.90 g tsp, 0.60 g mop and 0.60 g gypsum per pot were also incorporated into the soil before sowing. the pots were watered daily for easy germination. after the emergence and establishment, three uniform healthy seedlings per pot were allowed to grow for three weeks (21 dae) in equal environment. after three weeks of emergence, all the genotypes were divided into 6 groups. the treatment groups were; control (t1), water shortage (irrigated with 70% depletion of available soil water when wilting sign developed) from 21 dae (t2), 50 mm nacl irrigated from 21 dae (t3), 50 mm nacl irrigated from 21 dae + water shortage from 35 dae (t4), 100 mm nacl irrigated from 21 dae dae (t5) and 100 mm nacl + water shortage from 35 dae (t6). the control groups of plants were irrigated with tap water only. the experiment was arranged in two factors completely randomized design (crd) with 8 replications. plant samples were collected in 42 dae and different plant parts were separated and then oven dried at 70 ºc for 4 days to measure the dry weight. dried leaves were finely ground and the samples were dry-ashed at 500 ºc for 8 hours and then digested with concentrated hydrochloric acid. na and k concentrations were determined by a flame spectrophotometer. data were analyzed by mstat-c program and the treatment means were compared by using least significant difference (lsd). results and discussion plant height plant height of soybean genotypes significantly decreased under water stress, salt stress and their combination (fig. 1). under only water stress condition, significantly the tallest plant recorded in bari soybean 6 and the shortest in bd 2331 genotype. plant height was affected more in combined salt and water stress conditions than only in salt stress conditions in both the salinity levels (50 and 100 mm nacl), though the reduction was higher at higher salinity levels. at higher salinity (100 mm nacl), the tallest plant was recorded in ags 95 (26.13 cm) followed by bd 2342 (25.63 cm) and the shortest in galarsum (22.47 cm). at higher salinity (100 mm nacl) combined with water stress condition, the tallest plant recorded in bd 2342 (25.23 cm) followed by bgh02026 (25.13 cm), while the shortest in bd 2329 (20.10 cm). the reduction of plant height was also more in higher salinity both in only salt stress and, combined salt and water stress conditions (fig. 2). at higher salinity, the maximum relative plant height was recorded in bd 2331 (97.70%) followed by ags 95 (95.82 %) and the lowest in bd 2329 (75.95 %). but at higher salinity combined with water stress condition, the highest relative plant height recorded in ags 95 (87.28 %) followed by galarsum (86.84 %) and the lowest relative plant height in bd 2329 (67.75%). salt stress and water deficit significantly affected the plant height of soybean which is in agreement with ozturk et al. (2004); sari and ceylan (2002). osmotic potential of soil decreased due to salt water, and matric potential decreased due to water shortage in soil, which made interruption in water 49 genotypic differences in soybean under nacl salinity and water stress uptake by the plant resulting in reduction of shoot growth, is commonly expressed by stunted shoot growth. genotypic difference in the reduction of plant height due to salinity were also reported earlier by aziz et al. (2005); sultana et al. (2009) and padder et al. (2012) in mungbean, mannan et al. (2012) in soybean. 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes pl an t h ei gh t ( cm ) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws here, cont = control, ws = water stress, mm = nacl concentration. fig.1. plant height of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae 0 20 40 60 80 100 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes re la tiv e he ig ht (% ) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws here, cont = control, ws = water stress, mm = nacl concentration. fig. 2. relative plant height of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae shoot dry weight shoot dry weight of soybean genotypes sharply decreased when plants were exposed to water stress, salt stress and, combined salt and water stress (fig. 3). under only water stress conditions, bd 2342 produced the highest shoot dry weight (1.94 g) followed by bari soybean 6 (1.87 g), and the least recorded in bd 2331 (1.03 g). shoot dry weight was affected more in the combined salt and water stress conditions than only in the salt stress in both the salinity levels (50 and 100 mm nacl). but the reduction was higher in higher salinity levels. at higher salinity (100 mm nacl), the highest shoot dry weight recorded in bd 2342 (1.89 g) followed by bari soybean 6 (1.75 g) and the lowest in bgh 02026 (1.18 g). at the higher salinity combined with water stress condition, the highest shoot dry weight recorded in by bari soybean 50 khan et al. 6 (1.64 g), which was followed by bd 2342 (1.63 g) and the lowest recorded in bgh 02026 (1.18 g). the relative shoot dry weight of soybean reduced in water stress, salt stress and, combined salt and water stress conditions (fig. 4). under only water stress condition, the highest relative shoot dry weight recorded in bari soybean 6 (77.5 %) followed by galarsum (76.7 %) and the lowest in ags 95 (39.7 %). the relative shoot dry weight was reduced more in the combined salt and water stress conditions than only salt stress in both the salinity levels. at higher salinity (100 mm nacl), the highest relative shoot dry weight was recorded in galarsum (79.9 %) followed by bd 2331 (77.9 %) and the lowest in bd 2329 (50.2 %). but at higher salinity combined with water stress condition, the highest relative shoot dry weight wasrecorded in galarsum (68.4 %) followed by bari soybean 6 (68.0 %) and the lowest recorded in bd 2329 (44.1%). 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes sh oo t d ry we igh t (g /pl an t) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws here, cont = control, ws = water stress, mm = nacl concentration. fig. 3. shoot dry weight of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae 0.0 20.0 40.0 60.0 80.0 100.0 120.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes re lat ive sh oo t d ry we igh t (% ) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws here, cont = control, ws = water stress, mm = nacl concentration. fig. 4. relative shoot dry weight of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae wang et al. (2011) also reported that total biomass, shoot biomass, leaf biomass decreased significantly in saltcedar (tamarix chinensis) seedlings due to water scarcity under salt and water stress condition. under only water stress, when soil dries up, the matric potential decreases, therefore increases the resistance of water flow to the roots in a non-linear fashion (homaee et al., 2002). application of salt water increases in soil salinity. at given salt water content, the soil water potential reduces but does not reduce water flow to the roots. root cortical cells can osmotic ally adjust to some extent allowing water to readily move into the root. therefore, shoot dry weight of soybean was affected more in combined salt and water stress conditions than only in salt stress conditions. the finding is also in agreement with the findings of meiri (1984) that the matric potential preferentially affected the shoot growth of bean more than did the osmotic potential. 51 genotypic differences in soybean under nacl salinity and water stress under salt stress condition, cell expansion is reduced due to low turgor, beside these excess sodium ion damages cell membrane and organelles, resulting in plant growth reduction. the reduction in shoot dry weight due to salinity was reported by karim et al. (1993) in triticale, khan et al. (1997) in rice, aziz et al. (2005) in mungbean, waheed et al. (2006) in pigeonpea, jamil et al. (2007) in sugarbeet, sultana et al. (2009) in mungbean, chookhampaeng (2011) in pepper plant and mannan et al. (2012) in soybean. root dry weight root dry weight of soybean genotypes decreased under water stress, salt stress and, combined salt and water stress condition (fig. 5). under water stress, the highest root dry weight (0.30 g) was recorded in bgh02026 and the lowest (0.10 g) in bd 2342. root dry weight affected more in combined salt and water stress than only in salt stress in both the salinity levels (50 and 100 mm nacl). at higher level of salinity, the highest root dry weight (0.31 g)was recorded in both bd 2342 and bd 2331, and the lowest in bgh02026 (0.21 g). at higher level of salinity combined with water stress condition, the highest root dry weight (0.24 g) was recorded in both bd 2342 and ags 95 genotypes, and the lowest in bd 2331(0.19 g). the relative root dry weight reduced in water stress, salt stress and, combined salt and water stress conditions (fig. 6). the relative root dry weight was reduced more in combined salt and water stress conditions than only salt stress in both the salinity levels (50 and 100 mm nacl). at higher level of salt stress condition, the highest relative root dry weight recorded in galarsum (88.4 %) which was followed by bd 2331 (74.6 %) and the lowest recorded in bd 2329 (49.4%). at higher level of salt combined with water stress condition, the highest root dry weight also recorded in galarsum (69.8 %), which was followed by bgh02026 (61.1%) and the lowest recorded in bd 2329 (42.4 %). 0.00 0.10 0.20 0.30 0.40 0.50 0.60 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes ro ot d ry w eig ht (g /p lan t) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws here, cont = control, ws = water stress, mm = nacl concentration. fig. 5. root dry weight of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae 0.0 20.0 40.0 60.0 80.0 100.0 120.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 soybean genotypes re la tiv e ro ot d ry w ei gh t ( % ) cont ws 50mm nacl 50mm+ws 100mm nacl 100mm+ws 52 khan et al. here, cont = control, ws = water stress, mm = nacl concentration. fig. 6. relative root dry weight of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae under salt and water stress condition, cell expansion is reduced due to low turgor, beside these excess sodium ion damages cell membrane and organelles, resulting in reduction of root growth. wang et al (2011) reported that root biomass decreased significantly in tamarisk seedlings due to water severity under salt and water stress condition. decreased in radical dry weight of mungbean under salinity and water stress was also reported by padder et al. (2012). the reduction in root dry weight due to salinity were reported by aziz et al. (2005); sultana et al. (2009) in mungbean, waheed et al. (2006) in pigeonpea, jamil et al. (2007) in sugarbeet and chookhampaeng (2011) in pepper plant. dry matter distribution dry matter distribution in different plant parts of soybean genotypes as affected by water stress, salt stress and, combined salt and water stress condition is presented in fig. 7. all plant parts were reduced by stresses. under water stress, the highest stem in bari soybean 6 (0.77 g), petiole (0.25 g) and leaves (0.95 g) in bd 2342 were recorded while the lowest stem (0.36 g), petiole (0.14 g) and leaves (0.53 g) were recorded in bd 2331. all plant parts reduced more in all genotypes in the combined salt and water stress than only in the salt stress in both the salinity levels (50 mm and 100 mm nacl). but the reduction was more in leaves than stem and petiole. at higher salinity, the highest leaves dry weight recorded in bd 2342 (0.93 g), which was followed by bd 2329 (0.92 g) and the lowest recorded in bgh02026 (0.71 g). but at higher level of salinity combined with water stress condition, the highest leaves dry weight recorded in bd 2329 (0.81 g) and the lowest (0.59 g) in bgh 02026. under water stress condition, cell expansion of leaf is reduced due to low turgor, which is controlled by the processes related to cellular water uptake and cell wall extension (cramer and bowman, 1993). therefore, leaf area was decreased resulted in decreased leaves dry weight under salt and water stress condition. long term exposure to salinity lead to premature leaf senescence; and thus reduced the photosynthetic area (cramer et al., 1991) in soybean plants. the highest reduction of leaf dry weight in the genotype bgh02026 at 100 mm nacl salinity might be due to high salt load in the leaf. the salt that exceeds the capacity of compartmentation in the cell vacuoles of leaf causing salt to build up in the cytoplasm to toxic levels (munns, 2002; munns et al., 2006). the reduction in leaf dry weight due to salinity was reported by karim et al. (1993) in triticale, khan et al. (1997) in rice, aziz et al. (2005) in mungbean and mannan et al. (2013) in soybean. 0.0 1.0 2.0 3.0 4.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 genotypes d ry m at te r ( g/ pl an t) stem petiol leaf pods control water stress 53 genotypic differences in soybean under nacl salinity and water stress 0.0 1.0 2.0 3.0 4.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 genotypes d ry m at te r ( g/ pl an t) stem petiol leaf pods 0.0 1.0 2.0 3.0 4.0 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 bari soy 6 bd 2329 bd 2342 ags 95 bgh02026 galarsum bd 2331 genotypes d ry m at te r ( g/ pl an t) stem petiol leaf pods here, cont = control, ws = water stress, mm = nacl concentration fig. 7. dry matter accumulation in different plant parts of soybean genotypes as affected by salinity and water stress, and their combination at 42 dae sodium accumulation sodium (na) uptake in leaf tissue (%) of soybean genotypes was significantly affected by water stress, salt stress and, combined salt and water stress condition (table 1). the accumulation of na was lower in leaves of all the genotypes under water stress than control. significantly the lowest na content was found in bd 2329 (0.072 %), which was identical with bari soybean 6 (0.091 %) in only water stress treatment. the accumulation of na was more in the salt stress than in the combined salt and water stress conditions in both the salinity levels (50 and 100 mm nacl). results reveal that concentration of na increased with increasing salinity levels. genotypic differences were also observed in na accumulation. at higher level of salt stress (100 mm nacl), galarsum (0.223%) accumulated significantly the lowest concentration of na, which was identical by the accumulation of bd 2331 (0.226 %) and the highest was accumulated by bgh 02026 (0.495%). at higher level of salinity combined with water stress condition, galarsum (0.173%) was also accumulated lower amounts of na which was at par with the accumulation of bd 2331 (0.182%) and the highest in ags 95 (0.330 %).the results are in agreement with the earlier reports that tolerant genotypes accumulate lower amount of na than the salt sensitive ones (karim et al., 1992; khan et al., 1997; ahmadi et al., 2009; mannan et al., 2013). kao et al. (2006) also reported that differences among soybean species in leaf accumulation of na+ might be responsible for the differential sensitivity to nacl treatments. plant responses to salt and water stress have much in common phenomenon. salinity leads to many metabolic changes identical to those caused by water stress, and there are still salt-specific effects. accumulation of na+ in leaves results in necrosis and premature leaf senescence (munns, 2002). 50 mm nacl 50 mm nacl + ws 100 mm nacl 100 mm nacl + ws 54 khan et al. table 1. sodium (na) uptake in leaf tissue (%) of soybean genotypes as affected by salinity and water stress genotypes control water stress (ws) 50 mm nacl 50 mm nacl + ws 100 mm nacl 100 mm nacl + ws bari soy-6 0.136 0.091 0.319 0.179 0.390 0.226 bd 2329 0.083 0.072 0.275 0.195 0.330 0.198 bd 2342 0.143 0.121 0.283 0.217 0.358 0.303 ags 95 0.162 0.094 0.286 0.239 0.385 0.330 bgh 02026 0.165 0.143 0.413 0.253 0.495 0.292 galarsum 0.132 0.105 0.160 0.138 0.223 0.173 bd 2331 0.105 0.094 0.162 0.143 0.226 0.181 lsd(0.01) 0.022 cv (%) 4.98 potassium accumulation accumulation of potassium (k) in leaf tissue (%) of soybean genotypes was also affected by water stress, salt stress and, combined salt and water stress condition (table 2). the accumulation of k was higher in leaves under water stress than control. under only water stress treatment, significantly the highest k content was found in bd 2331 (2.52 %), which was identical by the accumulation of bd 2342 (2.42 %) and the lowest in ags 95 (1.96 %). the accumulation of k was more in the combined salt and water stress than in the salt stress conditions in both the salinity levels (50 and 100 mm nacl) in all the genotypes, except bari soybean 6 and bgh 02026. the accumulation of k decreased with increasing salinity levels. at higher level of salt stress (100 mm nacl), galarsum (1.75 %) accumulated significantly the highest amounts of k which was identical by the accumulation of ags 95 (1.70 %), bd 2331 (1.70 %) and bari soybean 6 (1.65 %). the least amount of k was accumulated by bd 2342 (1.55 %) at this level of salinity. at higher level of salinity combined with water stress condition, galarsum (1.80 %) also accumulated significantly the highest amounts of k, which was identical by the accumulation of bd 2331 (1.75 %), ags 95 (1.75 %) and bd 2329 (1.70 %), while bgh 02026 (1.34 %) accumulated the least.under water stress as well as under salt stress conditions, k plays an important role in osmoregulation, and stress tolerant genotypes accumulate higher amounts of k than susceptible ones (blum, 1988; qadar, 1988). here, soybean genotype galarsum accumulated higher amount of k in leaves than others under the salt and water stress conditions. a greater degree of salt tolerance in plants was found to be associated with a more efficient system for selective uptake of k over na (neill et al., 2002). the selective uptake of k in contrast to na is considered as one of the important physiological mechanisms contributing to salt tolerance in many plant species (poustini and siosemardeh, 2004). there was a negative relationship between na and k concentration in leaves. similar results had been observed by khan et al. (1997) and goudarzi and pakniyat (2008). table 2. potassium (k) uptake in leaf tissue (%) of soybean genotypes as affected by salinity and water stress genotypes control water stress (ws) 50 mm nacl 50 mm nacl + ws 100 mm nacl 100 mm nacl + ws bari soy-6 1.96 2.16 2.06 1.56 1.65 1.44 bd 2329 2.06 2.37 1.96 2.11 1.56 1.70 bd 2342 2.37 2.42 1.75 1.96 1.55 1.65 ags 95 1.75 1.96 1.80 1.85 1.70 1.75 bgh 02026 2.16 2.22 2.01 2.06 1.56 1.34 galarsum 1.85 2.16 1.96 2.06 1.75 1.80 bd 2331 1.70 2.52 2.16 2.16 1.70 1.75 55 genotypic differences in soybean under nacl salinity and water stress lsd(0.01) 0.15 cv (%) 3.74 conclusion the results of this study indicated that all the growth characters of the soybean genotypes sharply decreased when plants were exposed to water stress, salt stress and, combined salt and water stress conditions. variation in salt and water stress tolerance of soybean genotypes was obvious. among the genotypes, reduction in dry matter production was least in galarsum and bd 2331 in both salt and, combined salt and water stress conditions. these genotypes also accumulated lower amount of na and higher amount of k in leaf tissues under the salt stress and, the combined salt and water stress environments as compared to others. references abdulrahman, f. s. and g. s. williams iii. 1981. temperature and salinity regulation of growth and gas exchange of salicornia fruticosa (l.) l. oecologia. 48: 346-352. ahmadi, a., y. emam and m. pessarakli. 2009. response of various cultivars of wheat and maize to salinity stress. j. food agri. environ. 7: 123-128. aziz, m. a., m. a. karim, m. a. hamid, q. a. khalique and m. hossain. 2005. salt tolerance in mungbean: growth and yield response of some selected mungbean genotypes to nacl salinity. bangladesh j. agric. res. 30: 529-535. blum, a. 1988. salinity resistance. in: plant breeding for stress environments. crc press, florida. pp. 163179. chookhampaeng, s. 2011. the effect of salt stress on growth, chlorophyll content proline content and antioxidative enzymes of pepper (capsicum annuum l.) seedling. european j. sci. res. 49(1): 103109. cramer g. r. 1991. kinetics of maize leaf elongation. ii. responses of a sodium excluding cultivar and a na including cultivar to varying na/ca salinity. j. expt. bot. 43: 857–864. cramer g. r. and d. c. bowman. 1993. cell elongation control under stress conditions. in: handbook of plant and crop stress, m. pessarakli (ed.). marcel dekker, new york, pp.303-319. ghassemi-golezani, k. m. taifeh-noori, sh. oustan and m. moghaddam. 2009. response of soybean cultivars to salinity stress. j. food, agric.environ.7(2): 401-404. gill, k. s. 1990. effect of saline irrigation at various growth stages on growth, yield attributes and ionic accumulation pattern in green gram (phaseolus radiatus). indian j. agric. sci. 54: 210-212. gingrich, j. r. and m. b. russell. 1957. a comparison of effects of soil moisture tension and osmotic stress on root growth. soil sci. 84: 185-194. goudarzi, m. and h. pakniyat. 2008. evaluation of wheat cultivars under salinity stress based on some agronomic and physiological traits. j. agri. soc. sci.1: 35-38. greenway, h. and r. munns. 1980. mechanisms of salt tolerance in nonhalophytes. ann. rev.plant physiol. 31: 149-190. hayward, h. e. and w. b. spurr. 1943. effects of osmotic concentration of substrate on the entry of water into corn roots. bot. gaz. 105: 152-164. homaee, m., r. a. feddes and c. dirksen. 2002. a macroscopic water extraction model for nonuniform transient salinity and water stress. soil sci. soc. am. j., 66: 1764-1772. 56 khan et al. jamil, m., s. rehman and e. s. rha. 2007. salinity effect on plant growth, psii photochemistry and chlorophyll content in sugar beet (beta vulgaris l.) and cabbage (brassica oleraces capitata l.). pak. j. bot., 39(3): 753-760. kao, w., t. t. tyng, c. t. hung and n. s. chen. 2006. response of three glycine species to salt stress. environ. expt. bot. 56: 120-125. karim, m. a., e. nawata and s. shigenaga. 1992. dry matter production and distribution of mineral ions in different parts of the plant in hexaploid triticale. japanese j.crop sci. 61: 439-446. karim, m. a., e. nawata and s. shigenaga. 1993. effects of salinity and water stress on growth, yield and physiological characteristics in hexaploid triticale. japanese j.trop. agr. 37(1): 46-52. khan, m. s. a., a. hamid, a. b. m. salahuddin, a. quasem and m. a. karim. 1997. effect of sodium chloride on growth, photosunthesis and mineral ions accumulation of different types of rice (oryza sativa l.). j. agron.crop sci. 179: 149-161. khan, m. s. a. 2013. evaluation of soybean genotypes in relation to yield performance, salinity and drought tolerance. ph.d. dissertation. department of agronomy. bangabandhu sheikh mujibur rahman agricultural university. salna. gazipur-1703. maas, e. v. and g. j. hoffman. 1977. crop salt tolerancecurrent assessment. j. irrig. drain. div. asce. 103 (2): 115-134. maas, e.v. and poss, j.v. 1989. salt sensitivity of cowpea at various growth stages. irrig. sci. 10: 313-320. mannan, m. a., m. a. karim, m. m. haque, q. a. khaliq, h. higuchi and e. nawata. 2012. response of soybean to salinity: i. genotypic variations in salt tolerance at the vegetative stage. trop. agr. develop. 56(4): 117-122. mannan, m. a., m. a. karim, m. m. haque, q. a. khaliq, h. higuchi and e. nawata. 2013. response of soybean to salinity: ii. growth and yield of some selected genotypes. trop. agr. develop. 57(1): 3140. mannan, m. a., m. a. karim, m. m. haque, q. a. khaliq, h. higuchi and e. nawata. 2013. response of soybean to salinity: iii. water status and accumulation of mineral ions. trop. agr. develop. 57(1): 41-48. meiri, a. 1984. plant response to salinity: experimental methodology and application to the field. p. 284–297. in i. shainberg and j. shalhevet (eds.) soil salinity under rrigation. springer verlag, new york. munns r., r. a. james and a. läuchli. 2006. approaches to increasing the salt tolerance of wheat and other cereals. j. expt. bot. 57: 1025–1043. munns, r. 2002. comparative physiology of salt and water stress. plant cell environ. 25: 239–250. munns, r., r.a. hare, r. a. james and g. j. rebetzke. 2000. genetic variation for improving the salt resistance of durum wheat. aust. j. agric. res., 51: 69-74. neill, s., r. desikan, and j. hancock. 2002. hydrogen peroxide signalling. curr. opin. plant biol. 5: 388-395. ozturk, a., a. unlukara, a. ipek and b. gurbuz. 2004. effects of salt stress and water deficit on plant growth and essential oil content of lemon balm (melissa officinalis). pak. j. bot., 36(4): 787-792. padder, m. b, r. yadav and r. m. agarwal. 2012. effect of salinity and water stress in mungbean (vigna radiata) l. wilczek var. hum_1. plant sci. feed 2(9): 130-134. poustini, k. and a. siosemardeh. 2004. ion distribution in wheat cultivars in response to salinity stress. field crops res. 85: 12533. qadar, a. 1988. potassium status of the rice shoot as an index for salt tolerance. ind. j. plant physiol. 31: 388393. raptan, p. k., a. hamid, q. a. khaliq, a. r. m. solaiman, j. u. ahmed and m. a. karim. 2001. salinity tolerance of blackgram and mungbean: i. dry matter accumulation in different plant parts. korean j. crop sci. 46: 380-386. 57 genotypic differences in soybean under nacl salinity and water stress sari, a. o. and a. ceylan. 2002. yield characteristics and essential oil composition of lemon balm (melissa officinalis l.) grown in the aegean region in turkey. tr. j. agric. forestry, 26(4): 217-224. sultana, m. s., m. a. karim, f. hossain, m. a. halim and m. t. hossain. 2009. effect of salinity on growth and yield of two mungbean varieties differing in salinity tolerance. bangladesh j. life sci. 21(2): 4752. tester, m. and r. davenport. 2003. na+ resistance and na+ transport in higher plants. ann. bot. 91: 1-25. waheed, a., i. a. hafiz, g. qadir, g. murtaza, t. mahmood and m. ashraf. 2006. effect of salinity on germination, growth, yield, ionic balance and solute composition of pigeon pea (cajanus cajan l. millsp). pakistan j. bot. 38(4): 1103-1117. wang, wei, r. wang, y. yuan, n. du and w. guo. 2011. effects of salt and water stress on plant biomass and photosynthetic characteristics of tamarisk (tamarix chinensis lour.) seedlings. afr. j. biotechnol. 10(78): 17981-89. microsoft word final.doc � �������� ��� �������������������������� ���� �!"#$���� �!"#$���� �!"#$���� �!"#$����#%#%#%#%����!"���&���$'�(��$!"$&�)*)!�+�#%� (��$'�,-#()�!"���&���$'�(��$!"$&�)*)!�+�#%� (��$'�,-#()�!"���&���$'�(��$!"$&�)*)!�+�#%� (��$'�,-#()�!"���&���$'�(��$!"$&�)*)!�+�#%� (��$'�,-#()� ' -"$&�'-*�)��)#$' -"$&�'-*�)��)#$' -"$&�'-*�)��)#$' -"$&�'-*�)��)#$���� � .��+��/�.��+��/�.��+��/�.��+��/������� � �� � �� � �� � ������&��$��.� ����&��$��.� ����&��$��.� ����&��$��.� ����������� ������ ������ ������ �����)� 0� )� 0� )� 0� )� 0� ������%��-� �1����%��-� �1����%��-� �1����%��-� �1��������������"�� ��2�����"�� ��2�����"�� ��2�����"�� ��2��������� ��)��2� � 32��42523�#5523� ��#��%� 1�-� �� 3 �'262 2������������ ��� 237�47 ���-� �� 3 �"� 42474����������� � �)32��42523�#5523� ��#��%� 1�-� �� 3 �'262 2������������ ��� 237�47 ���-� �� 3 �"� 42474����������� � �'2 �34� ��!�8�,�92������-"��&�:2;7 ���������� � �)��2� �)32��42523�#5523� ��)�2��-� �7 3� �'�6���;1��4�"� 42474����������� � ,� � ;�����3���74 � ��<� � ��<��2=>� ���3�1� /�>�9� � ��/�>�9� � ��/�>�9� � ��/�>�9� � ��!2�������;���42��� > 4�1��7;�����3 �;� ���� �< 4 �34�< 4 �34�< 4 �34�< 4 �34���� ���� ;����� 3 �; � 37�426�42��� 2�� 4 �� �74 � 3��4 ��� 3�� 4��� � ��� �5��������� � 2 � �2124��� �7�� 4�� ��6>�4�?47 ��� �2��924 � ��4�� �3� 2����5�5�����9�4� ������� �>�5�� �5�����<>� ��6>� �2�5����� ! ��; � ��4� 47�>�9� ��� 2�����4��52����74�42������ �@72 �1��4����� 724�<���;���42��� > 4�1� 5� � 7;����� 3 �; ��� $71<� � �5� 42������ �49�� 4�� 5�7 � ;� � �� 9� � �6��7�4��� ������ 924 � 49�� ;���42��� > 4�1 �62:���<�������5��4�;���42��� > 4�1 �7 2���5�7 �3 �; � �20���4�1�4���)����71� �>3�;� 2371� ����� < 2�a��� �)�� 1��������� ����� <244� � ��7 �� �+�1� �23�� 3 � ��42�� ���� ���� 37371<� � �,73712 � �4267 �����! �� 3 �; � �9��� 4 �4� 2�3 �� ��� 5 724� >2����924 � 2�3 �� 2��� �71<� � �5� 42������ 2�� <�4 � ;���42��� > 4�1���74� <��� ;���42��� > 4�1� ; ��73��� 2� � � 5 724� >2�����< 2�a���b�����4� �����4�1�4��cd����4� �����<244� ��7 ������c�4� ��������37371<� ���d�c� 4� ����� 4 ��� 5��4�;���42��� > 4�1�����4 � ��<���;���42��� ��;��� 4��� 3�;��3 �;���1����<>� �� �>� ��6>� �2�5����2������3 �; ����� ���� "�4 ��7342��"�4 ��7342��"�4 ��7342��"�4 ��7342������ ���� �������� � � ���4 �;23���1�� ����3�21�4���# ���23�1�44� �3��4��4�2�� �2��2 ���;�����4������ �� 3�21�423�3���242�� �����2 ��255237�4�4��3�� � 6���4��� 2� ���6���2��4 �;23������� 7<4 �;23���3���242�� � �� 72>�����c�e���-,�����d����3����23���3���242�� ������4�5�6� �; �34232���17�42;���3 �;;2���� � �3 2�62��� 2� � >2��� �� %� 1� � � �92��� 7;����� 3 �; � 2 02��� 3�21�4�� 6��� 2� � 6� >� �54��� � �� 5 7 4 �4��� 924 � 3 �;� 5�2�7 �� �7�� 4�� 2�7���42���� ��9� 3 �;;2��� 2�4�� 24>� �337 � �7�� 4�� 42���� 7<1� ���3���5�3 �;;���������7 2���1�� ���������>�2�� �2��� >2���; �3� ����30��5�2 2��42���2�� � >� �� ��������� �>�42����9�4� �1����4 ��42�����3� > 4�1�2��4 �� �74 � �� ��2����5��������� � �� �; ��73426��924 � ��� 4� �26� 2523�42����5� 3 �;;2����( ��7342��� �5� 6���4�<�� � ���� 5 724 � 2 � 4 �� ��� 4����4��!���1��� � 6� 4�� ��4��9�4� � �3�����3��>� �2������ �2��1�2 47 ����;��4��� �;2��>��� �� ( �6�2� �; �<��1�5� �6���4�<���; ��7342����"��4 2 �� ����54� �!���1��� � 6� 4�6���4�<���37�426�42��� 2 �6� >��255237�4�<�3�7 ���5� �2��1�2 47 �� 2� ��4�� ��� � 7�4�4 2 �421��2 ���4� 724�<���5� �6���4�<��� ����f7230�& �92���% 724 ��f&%��37�426�42�����54� �4 �4� �2��1�2 47 ��2 ���3 �� 2�����>�<>���>����� �4�1�47 24>� 4����24g ���1�����<>� ��6>� �2�5���������� �>�5�7 �5�����4 �7� �42���� 7 �� ��7 2��� ;� 4�1�� ����� >� �� ����� !2������924 �;���42��� > 4�1 �3�7���<���������;42���4��2�3 �� ��>2��� �<>�5� 1� �2��4 �� �74 � �� ��2��� �5� �������� � �7 2��� ;� 4�1�� ���� � >� �� ���� !2������ ���� ;���42��� > 4�1 � 5�32�24�4�� � �2����� ���� �� �42��� 2�� ���� �2�� 4>;� � 9 23 � ��73� � ����2��� �4�� ; �1�4� � �;2�� ��4� ��6���;1��4� �+7 �� �� �������h�4� � � 6� 42��� 4�3 �2@7� � �3 2�6��� 4 �7� � �255� ��4� 42������ > 4�1 �9�7��� ��;�2��1�2 47 ��3�� � 6�42����4 7 �21; �62���� �94 �����>2�����5�4�1�4�� ��� !2����������;���42��� > 4�1�2 ���; �3423��9 23 �3 ���� �4 �� �2��; �;� 42� ����62 ��1��4�����3 �;� ; ��7342����!2������4�3 �2@7� �� ��7 ���2��� �� �4��; �62���������� ����<���� ��4���6���;1��4�� ��� �� � ��4����� 9���� 3��4 ��� ���� 1������ 3 �;� � 2�7� �� ��6��2��� 4 �� 7 5�3�� 5� � 7�25� 1� 2 2��42��� ���� 2�3� ;� �42����5�1��7 � �����5� 42�2:� ��,�<�������c���� ! �� � �� 3 ��55� 4���� � 2�7����55�34��5�42������924 �;���42��� > 4�1���� 7< �@7��4�3 �;�>2��� ��5� �255� ��4�6���4�<�� �����5 724 � �6����4�<���� �;� 4����! � �5� ���4 ��; � ��4� 47�>�9� �2�242�4��� 4�� �6��7�4�� 4 �� �55�3426�� ���� �55232��4� 42������ > 4�1� 5� � � �92��� 7;����� 3 �; � �7 2��� ;� 4� 1�� ����� >� �� ���2��4 �� �74 � �� ��2����5��������� �� ���� +�4� 2�� �����+�4 �� +�4� 2�� �����+�4 �� +�4� 2�� �����+�4 �� +�4� 2�� �����+�4 �� ���� ���� ! �� 47�>�9� �3���734����4�(�47�0 ��2� ��� ����i����$����i�����������'7102����i�d��$����i���� ���� (�47�0 ��2� �2 4 234� ���� � ���0 �4 2� ��� � ���i���� $�� ��i���� ���� � ���0 �4 2� �2 4 234� 2�� 4 �� �74 � ��3�� 4��� ��2����5��������� �7��� �5� 1� j�52����3���242����7 2���4 ��� >� �� �����54� � 9�4� �� ��� 23�� � 6� 4�� �5� �����������! �� �?;� 21��4�9� � ��2���74� �4� ����12:��� 3�1;��4�� <��30� �� 2��� �-,�'��924 � 49�� 5�34� � �62��� 2?� �2 ;� ��� �;�23�42�� � ����� 5� 1� j � 52����9� � 3�� 2�� ���� ����� �;�23�42����2��4 ����255� ��4���3�42�� ��%�34� ��e�4 ���42������ > 4�1�2����49�� ;� ��4 ���;� �����5�7 �;� �9� �������924 �3�7�4 >�;��7� �5����92���3 � �;� �����5�34� ��e� 49��4>;� ��5�;���42���1�4 ���2����<���;���42�������5��4�;���42����! ��7�24�;��4� 2:��9� �c1���d1�� ! ���?;� 21��4�9� � �;��4���924 �5�7 �3 �; ���1��>�� 4�1�4�� ���-"�4�1�4�������< 2�a��� ���-"� <��7������ <244� � ��7 �� �!2��� ���� 37371<� � �$�������� ������ ! �� �?;� 21��4��� ;��4 � 9� �� 5� 42�2:���5����92���4 ��/ 2 2�( �a7042�.�4<�2����-"���������! ��5� 42�2:� � �4��5� �< 2�a���9� ����d� 0�� ����$��d��0�� ����(���c��0�� ����/�����0�� ����)��������4� ���,�9�7����4�1�4��9� ������ 0�� ����$�����0�� ����(������0�� ����/�����0�� ����)��������4� ���,�9�7����<244� ���7 ��9� �� bd�0�� ����$�����0�� ����(�����0�� ����/���d�0�� ����)������0�� ����k��������4� ���,�9�7������� 37371<� �9� ��d��0�� ����$�����0�� ����(�����0�� ����/��b�0�� �����>; 71������0�� ����k������ d� 4��� ���,�9�7���� ! 2 4>� ��> � ���� ����2�� � �5� 4 �� 3 �; � 9� �� 4 �� ;���4��� ��� ��� 4�� ��� '�3�1<� ������5� �4�1�4������< 2�a�����244� ��7 ������37371<� � ����9� �� �9���2 �34�>��54� � ; �;� ��� 4 �� <��� 2��e� � 4� 9��0� �5� ���7� >� ������ +� 0�4�<��� 2;��2��� 5 724 � �5� 4�1�4�� 9� �� � 6� 4���5 �1��d�%�< 7� >�4���c�+� 3 �������� 2�a��� � 6� 42���9� ������5 �1����+� 3 �4�� ����; 2���������244� ���7 ��9� � 4� 4�������d�'�)�����37371<� �9� ��d�d��'�)���%� 42�2:� � �;;�23�42��� 1�4 ��� ���� �4 � � �� ���123� ; �3423� � 9� �� ����� � � ;� � / 2 2� ( �a7042� .�4<�2� ���-"��������������� ���123�������62 ��1��4�����4��9� �� �3� ����3� �57��>��)�2��1�2 47 ����4�� 9� �� �3� �����4������> �2�4� 6����6� �4 ���?;� 21��4���;� 2����� ���� -� 7�4 �����'2 37 2��-� 7�4 �����'2 37 2��-� 7�4 �����'2 37 2��-� 7�4 �����'2 37 2������ ���� �55�34��5�42���������< 2�a���55�34��5�42���������< 2�a���55�34��5�42���������< 2�a���55�34��5�42���������< 2�a��� *2��������>2�����44 2<74� ��5�< 2�a����55�34���<>�42������ > 4�1 �9� �� �9��2��!�<������! �� 2� � 4� �71<� ��5�5 724 �;���4���9� �5�7���2����;� � ��5�42����������24�9� �2�3 �� ���924 �2�3 �� 2���4 �� �71<� � �5� 42������� ���2�� 2��262�7��� 5 724� 9�2� 4� 9� � 2� � 4� 2�� �� ;� � � �5� 42������ ���� 24� 9� � ��3 �� ���924 ���3 �� 2���4 ���71<� ��5�42�������"4�12� 4�<���7��4��5 724� 2:���%2����>�4 �� 2� � 4� 5 724� >2����9� � �<4�2���� 5 �1� �� ;� � � �5� 42������ �b����� 4� ����� 5����9��� <>� �� ;� � � �5� 42������ �����d�4� ������ � �55�34��5�;���42��� > 4�1 ����< 2�a���55�34��5�;���42��� > 4�1 ����< 2�a���55�34��5�;���42��� > 4�1 ����< 2�a���55�34��5�;���42��� > 4�1 ����< 2�a������ (���42��� > 4�1�9� � 4�42 423���>����� 2��2523��4�2��>2������������>2����3��4 2<742���4 �24 ��!�<������� (���42���2��<��� > 4�1�9� ��< � 6���2�� 2� � �2������3� � �4 ���;���42���2��5��4� > 4�1 ��"4�12� 4� ��� !2����������(���42���)> 4�1��5� ;�����, �; �� <�� �7�� 4�� <�44� �1�����1��4� ���� 3�� � 6��� ; �������� �2�� 1�2 47 �� ���� 24 � � 3�;�� 4 �� 42���� 7 ��������� �>� �2�5����� � 5�7 �5������(���42��� 2��<���; ��73��� 2� � � 5 724�>2���� �������4� ����� ������9� �2��5��4�;���42��� > 4�1��������4� ������� � "�4� �342����55�34��5�42������924 �;���42��� > 4�1����< 2�a��"�4� �342����55�34��5�42������924 �;���42��� > 4�1����< 2�a��"�4� �342����55�34��5�42������924 �;���42��� > 4�1����< 2�a��"�4� �342����55�34��5�42������924 �;���42��� > 4�1����< 2�a������ ! ��2�4� �342����55�34��5�42������924 �;���42��� > 4�1�9� �; � ��4���2��4�<������$71<� ��5�5 724 � ;���4���6� 2��� 2��2523��4�>��1�����255� ��4�42������ > 4�1��! �� 2� � 4��71<� ��5�5 724 �;���4���9� � 5�7���2����;� � ��5�42����������24�9� ���3 �� ���9 ��� 2�3 �� ���2��42������ > 4�1��$����5�5 724 � ;���4�������2��262�7���5 724�9�2� 4�9� ��4 ��1� 4�624���3 � �34� �5� �3��4 2<742���5 724�>2�����% �1� 4 2 � ;�2�4� �5� 62�9�1�?2171��71<� � �5� 5 724 � ;� � ;���4� ��6�� 1���� 2:�� ���� ��9� 4� �71<� � �5� 5 724 �;� �;���4���6��<2�� 2:��5 724 ��! �� 2� � 4�2��262�7���5 724�9�2� 4�9� ��< � 6���2������;� ��5� 42������2��<�4 �<�������5��4�;���42���1�4 �� ��! �� 2� � 4�5 724�>2�����b�����4� �����9� �5�7���2���� ;� � ��5�42������924 �<�����?4�4����;� � ��5�42������2��5��4�;���42��� > 4�1��b���b�4� ������% �1� 4 ��2�4� �342���24�9� �3��� �4 �4�9 ���42������;� � �2�3 �� ���924 �;���42���2��<���4 ���5 724�>2���� 2�3 �� ����! ����9� 4�5 724�>2������ ���< � 6���2����;� � �42������2��<�4 �;���42��� > 4�1��� � !�<������������*2��������>2�����44 2<74� ��5�< 2�a���� ��55�34���<>��255� ��4�42������; �3423� �� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� ��;� � ��5�42������ ������ ���c�� ������ ��;� � ��5�42������ �d���� �c���� ����d� ��;� � ��5�42������ ���b�� bd�bb� b����� �)'����d�� ���b� ����� b��d� ���� !�<���������*2��������>2�����44 2<74� ��5�< 2�a���� ��55�34���<>��255� ��4�;���42��� > 4�1�� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2��<��� �b���� �d���� ������ (���42���2��5��4� > 4�1� �d���� ���cc� ������ !�4� 4� $)� $)� $)� � !�<��������� "�4� �342����5�;���42��� > 4�1����� 42������; �3423� ���� 4 ��>2��������>2�����44 2<74� ��5� < 2�a��� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2�� <��� ��;� � ��5�42������ ������ ������ ������ ��;� � ��5�42������ �d���� ������ ���db� ��;� � ��5�42������ ������ ���bb� b����� (���42���2�� 5��4� > 4�1� ��;� � ��5�42������ ������ ������ ���c�� ��;� � ��5�42������ �d���� ���bb� �b���� ��;� � ��5�42������ ������ b��bb� b���b� �)'����d�� ����� ����� ����� ,���l�� b�b�� ����� ��d�� � �55�34��5�42���������4�1�4��55�34��5�42���������4�1�4��55�34��5�42���������4�1�4��55�34��5�42���������4�1�4�� *2��������>2�����44 2<74� ��5�4�1�4���55�34���<>�42������ > 4�1 �9� �� �9��2��!�<������! �� 2� � 4� �71<� ��5�5 724 �;���4���9� �5�7���2����;� � ��5�42����������24�9� ���3 �� ���924 ���3 �� 2���4 �� �71<� ��5�42����������2��2��262�7���5 724�9�2� 4�9� � 2� � 4�2����;� � ��5�42����������24�9� � �1�� ��� �� � ��4����� 4�� 4 �� �� ;� � � �5� 42������� %2����>� 4 �� 2� � 4� 5 724� >2����9� � �<4�2���� 5 �1� �� ;� � � �5� 42������ �c��d��4� �����5����9���<>���;� � ��5�42�������d���b�4� ������ � �55�34��5�;���42��� �55�34��5�;���42��� �55�34��5�;���42��� �55�34��5�;���42��� > 4�1 ����4�1�4�> 4�1 ����4�1�4�> 4�1 ����4�1�4�> 4�1 ����4�1�4����� (���42��� > 4�1�9� � 4�42 423���>����� 2��2523��4�2��>2������������>2����3��4 2<742���4 �24 ��!�<���d��� (���42���2��<��� > 4�1�9� ��< � 6���2�� 2� � �2������3� � �4 ���;���42���2��5��4� > 4�1 ��"4�12� 4� <�� �7�� 4�� <�44� �1�����1��4� ���� 3�� � 6��� ; �������� �2�� 1�2 47 �� ���� 24 � � 3�;�� 4 �� 42���� 7 ��������� �>� �2�5����� � 5�7 �5������(���42��� 2��<���; ��73��� 2� � � 5 724�>2���� �d�����4� ����� ������9� �2��5��4�;���42��� > 4�1��d�����4� ������� � "�4� �342����55�34��5�42������924 �;���42��� > 4�"�4� �342����55�34��5�42������924 �;���42��� > 4�"�4� �342����55�34��5�42������924 �;���42��� > 4�"�4� �342����55�34��5�42������924 �;���42��� > 4�1����4�1�4�1����4�1�4�1����4�1�4�1����4�1�4����� ! ��2�4� �342����55�34��5�42������924 �;���42��� > 4�1�9� �; � ��4���2��!�<���b��$71<� ��5�5 724 � ;���4���6� 2��� 2��2523��4�>��1�����255� ��4�42������ > 4�1��! �� 2� � 4��71<� ��5�5 724 �;���4���9� � 5�7���2����;� � ��5�42����������24�9� ���3 �� ���9 �����3 �� ���2��42������ > 4�1�2��<�4 �5��4����� <���;���42��� > 4�1��$����5�5 724 �;���4�������2��262�7���5 724�9�2� 4�9� ��4 ��1� 4�624���3 � �34� � 5� �3��4 2<742���5 724�>2�����% �1�4 2 �;�2�4��5�62�9�1�?2171��71<� ��5�5 724 �;���4�����6�� 1���� 2:��������9� 4��71<� ��5�5 724 �;���4�����6��<2�� 2:��5 724 ��! �� 2� � 4�2��262�7���5 724�9�2� 4�9� � �< � 6��� 2�� ���� ;� � �5� 42������ 2�� <�4 � <��� ���� 5��4� ;���42��� > 4�1 �� ! �� 2� � 4� 5 724� >2���� �cd����4� �����9� �5�7���2����;� � ��5�42������924 �<�����?4�4����;� � ��5�42������2��5��4�;���42��� > 4�1�����bb�4� ������% �1�4 �� 2�4� �342��� 24�9� �3��� � 4 �4�9 ���42������;� � � 2�3 �� ���924 � ;���42���2��<���4 ���5 724�>2����2�3 �� ����! ����9� 4�5 724�>2������ ���< � 6���2����;� � �42������2�� <�4 �<�������5��4�;���42��� > 4������ ���� !�<���������*2��������>2�����44 2<74� ��5�4�1�4��� ��55�34���<>��255� ��4�42������; �3423� �� ! ��41��4 � $����5�5 724 �;���4��� "��262�7���5 724�94������ % 724�>2�����4� ����� ��;� � ��5�42������ ���c�� ���d�� ������ ��;� � ��5�42������ ������ �c���� d���b� ��;� � ��5�42������ ���bb� ������ c��d�� �)'����d�� ��bc� d���� b�c�� ���� !�<���d�����*2��������>2�����44 2<74� ��5�4�1�4��� ��55�34���<>��255� ��4�;���42��� > 4�1�� ! ��41��4 � $����5�5 724 �;���4��� "��262�7���5 724�94������ % 724�>2�����4� ����� (���42���2��<��� ������ �b�bb� d����� (���42���2��5��4� > 4�1� �c���� ������ d����� !�4� 4� $)� $)� $)� ���� !�<���b����� "�4� �342����5�;���42��� > 4�1����� 42������; �3423� ���� 4 ��>2��������>2�����44 2<74� ��5� 4�1�4�� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2�� <��� ��;� � ��5�42������ ������ ������ �b���� ��;� � ��5�42������ �d���� �c�bb� bd�bb� ��;� � ��5�42������ ���bb� ������ cd���� (���42���2�� 5��4� > 4�1� ��;� � ��5�42������ ���bb� ���bb� ������ ��;� � ��5�42������ ������ �c���� d��bb� ��;� � ��5�42������ �d�bb� �d�bb� ���bb� �)'����d�� ��c�� ����� ����� ,���l�� ��d�� ������ d���� ��� !2����������(���42���)> 4�1��5� ;�����, �; �� �55�34��5�42���������<244� ���7 ��55�34��5�42���������<244� ���7 ��55�34��5�42���������<244� ���7 ��55�34��5�42���������<244� ���7 �� �55�34��5�42������; �3423� ����4 ��>2�����5�<244� ���7 ��9� �; � ��4���2��!�<������!2������; �3423� � � �� ���� �5� 4 ��1� 4� 21;� 4��4� ;� 4 � �5�1�����1��4� ; �3423� � ���� 24� 3��4 2<74� � 4�� 4 �� >2������ ! � ��9� ���� 2��2523��4��255� ��3�� 2���71<� ��5� 5 724 �;� �;���4�����2��� 2��262�7��� 5 724�9�2� 4� 9� � 2� � 4�2����;� � ��5�42������������9� 4�2����;� � ��5�42�������-��� �2���>2����24�9� �5�7��� 4 �4�9 �����;� � ��5� 42������9� �7 ��� 4 ���1�?2171� 5 724�>2���� �����d� 4� �����9� � 5�7������� ��9� 4� 2�� �� ;� � � �5� 42������ �����d� 4� ������ -�� ��� 12� 4� <�� <� 2��� 4 �4� 1�?2171� 42������ �4�2���� 1�2 47 �� 2�� 4 �� �2�� ���� 3 �;� 3��� 7 626�� 5� � ����� � ;� 2���� 9 23 � 9� � 7�421�4��>� ; ��73���1�?2171�5 724�>2����� � �55�34��5�;���42��� > 4�1����<244� ���7 ��55�34��5�;���42��� > 4�1����<244� ���7 ��55�34��5�;���42��� > 4�1����<244� ���7 ��55�34��5�;���42��� > 4�1����<244� ���7 ����� �55�34��5�;���42��� > 4�1 ����4 ��>2�����5�<244� ���7 ��9� �; � ��4��� 2��!�<���c��! � ��9� ���� 2��2523��4��255� ��3��2�������5�5 724 �;���4�������2��262�7���5 724�9�2� 4��(���42���2��<���; ��73��� 2� � � 5 724� >2���� ����c�� 4� ����� ���� ��9� � 2�� 5��4� ;���42��� > 4�1� ������� 4� ������ "4�9� � �7�� 4�� �71<� ��5�5 724 �;���4���� 2��262�7���5 724�9�2� 4��� �� 2� � �2��<���;���42��� > 4�1�����4 � �<��� ;���42��� > 4�1 � 3�� � 6��� ; �������� �2�� 1�2 47 �� ���� 24 � � 3�;�� 4 �� 42���� 7 ��� ���� �� �>� �2�5����� �5�7 �5������� ���� "�4� �342����55�34��5�42������924 �;���42��� > 4�1����<244� ���7 �"�4� �342����55�34��5�42������924 �;���42��� > 4�1����<244� ���7 �"�4� �342����55�34��5�42������924 �;���42��� > 4�1����<244� ���7 �"�4� �342����55�34��5�42������924 �;���42��� > 4�1����<244� ���7 ����� "�4� �342����55�34��5� 42������; �3423� �����;���42��� > 4�1�9� �; � ��4��� 2��!�<������$71<� ��5� 5 724 �;���4���6� 2��� 2��2523��4�>��1�����255� ��4� 42������ > 4�1��.2� � 4��71<� ��5� 5 724 �;���4��� 9� �5�7���2������;� � ��5�42����������24�9� ���3 �� ���9 ���2�3 �� ���2��42������ > 4�1�2��<�4 � <�������5��4�;���42��� > 4�1��$����5�5 724 �;���4�������2��262�7���5 724�9�2� 4�9� ��4 ��1� 4�624��� 3 � �34� �5� �3��4 2<742���5 724�>2�����% �1�4 2 �;�2�4��5�62�9�1�?2171��71<� ��5�5 724 �;���4��� ��6�� 1���� 2:��������9� 4��71<� ��5�5 724 �;���4�����6��<2�� 2:��5 724 ��! �� 2� � 4�2��262�7���5 724� 9�2� 4� 9� � �< � 6��� 2�� �� ;� � � �5� 42������ 2�� <�4 � <��� ���� 5��4� ;���42��� > 4�1�� % �1� 4 �� 2�4� �342���24�9� �3��� �4 �4� 2� � 4�5 724�>2��������c�4� �����9� �5�7���2����;� � ��5�42������924 � <���;���42��� > 4�1��! �� �3���� 2� � 4� 5 724�>2���� ��c�d�4� �����9� ��<4�2����5 �1�;���42��� 2�� 5��4� > 4�1�924 ���;� � ��5�42�������%��4�;���42���924 ���;� � ��5�42��������6��4 ����9� 4�5 724�>2���� ������4� ��������9�>2����2����;� � ��5�42������9� �; �<�<�>��7��4����9�1�2 47 ��3��4��4��5�4 �� �2�� 9 23 �3�7 � ��� �>� 2;��2���������924 � 1���� � 2:���5�5 724 ��7�421�4��>���9� �>2��������2���2��3� �� �5�<���;���42��� > 4�1�;���4� 7 626�� 2��1��>���> ��7�� 4��� 3�;2����� �>� 5�7 � 5������ � �2�5����� h � �� �� ;���42��� 2�� 5��4� > 4�1�;���4� ��1����9 ��� �� �>� �2�5���� �337 � 4 �4� 2 � ��4� � 4���� �5� � 6� 4�2��+� 3 �4���; 2���� � �55�34��5�42���������37371<� �55�34��5�42���������37371<� �55�34��5�42���������37371<� �55�34��5�42���������37371<� � �55�34��5�42������; �3423� ����4 ��>2�����5�37371<� �9� �; � ��4���2��!�<�������!2������; �3423� � � �������5� 4 ��;� 4 ��5�1�����1��4�; �3423� ����� 24�3��4 2<74� � 4�� 4 ��>2�����$71<� ��5� 5 724 � ;���4����2��262�7���5 724�9�2� 4�9� � 2� � 4�2����;� � ��5�42����������24�9� ���9� 4�2����;� � ��5� 42�������$��� 2��2523��4� 6� 2�42���9� � �< � 6��� 2�� 2��262�7��� 5 724�9�2� 4��-��� �2��� >2���� 24�9� � 5�7���4 �4�9 �����;� � ��5� 42������9� �7 ���4 ���1�?2171�5 724�>2���� ������4� �����9� �5�7��� ���� ��9� 4� 2�� �� ;� � � �5� 42������ ������ 4� ������ -�� ���12� 4� <�� <� 2��� 4 �4�1�?2171� 42������ �4�2���� 1�2 47 �� 2�� 4 �� �2�� ���� 3 �;� 3��� 7 626�� 5� � ����� � ;� 2���� 9 23 � 9� � 7�421�4��>� ; ��73���1�?2171�5 724�>2����� � � � ��� �� � ��4����� !�<���������*2��������>2�����44 2<74� ��5�<244� ���7 ��� ��55�34���<>��255� ��4�42������; �3423� �� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� ��;� � ��5�42������ ���d�� ��c�d�� ����d� ��;� � ��5�42������ ���c�� �����d� ���d�� ��;� � ��5�42������ ���b�� ����c�� ����d� �)'����d�� $)� b���� d�b�� ���� !�<���c�����*2��������>2�����44 2<74� ��5�<244� ��7 ��� ��55�34���<>��255� ��4�;���42��� > 4�1�� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2��<��� ���b�� ����d�� ���c�� (���42���2��5��4� > 4�1� ������ ������� ������ !�4� 4� $)� $)� m� ! ��1����>2������ ��+n������)'n���b���$n���9� � 2��2523��4�>�� ��4� �4 ���:� ���4���nd�d���49��4�2��;n������; �62�2��� �62���3�� 4 �4� 4 ��<���;���42��� 2 ��55�3426�� 2�� 2�3 �� �� 5 724�>2��������dl�,�� "���<�74�1����5 724�>2���� 2�3 �� �� 2 � ���d��� ������ � !�<��������� "�4� �342����5�;���42��� > 4�1����� 42������; �3423� ���� 4 ��>2��������>2�����44 2<74� ��5� <244� ���7 �� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94������ % 724�>2���� �4� ����� (���42���2�� <��� ��;� � ��5�42������ ������ ������ �d��� ��;� � ��5�42������ ������ ������ ����� ��;� � ��5�42������ ������ ������ ���c� (���42���2�� 5��4� > 4�1� ��;� � ��5�42������ ���d�� ��c��� ����� ��;� � ��5�42������ ���b�� ����d� ���b� ��;� � ��5�42������ ������ ������ �c�d� �)'����d�� ���b� ����� ����� ,���l�� d���� ����� ���� ���� �55�34��5�;���42��� > 4�1����37371<� �55�34��5�;���42��� > 4�1����37371<� �55�34��5�;���42��� > 4�1����37371<� �55�34��5�;���42��� > 4�1����37371<� � �55�34��5�;���42��� > 4�1 ���� 4 ��>2�����5�37371<� �9� �; � ��4��� 2��!�<�������! � ��9� ���� 2��2523��4��255� ��3�� 2�������5� 5 724 �;���4����(���42��� 2��<���; ��73��� 2� � � 5 724�>2���� ����d� 4���� ����� ���� ��9� � 2�� 5��4� ;���42��� > 4�1�� "4� 9� � �7�� 4�� �71<� � �5� 5 724 � ;���4���� 2��262�7��� 5 724� 9�2� 4��� �� 2� � � 2��<���;���42��� > 4�1�����4 � �<���;���42��� > 4�1 � 3�� � 6���; �������� �2��1�2 47 ������24 �� 3�;��4 ��42���� 7 ��������� �>� �2�5����� �5�7 �5������� ���� "�4� �342����55�34��5�42������; �3423� �����;���42��� > 4�1����37371<� �"�4� �342����55�34��5�42������; �3423� �����;���42��� > 4�1����37371<� �"�4� �342����55�34��5�42������; �3423� �����;���42��� > 4�1����37371<� �"�4� �342����55�34��5�42������; �3423� �����;���42��� > 4�1����37371<� ����� "�4� �342����55�34��5�42������; �3423� �����;���42��� > 4�1�9� �; � ��4���2��!�<�������$71<� ��5� 5 724 � ;���4��� 6� 2��� 2��2523��4�>� �1���� �255� ��4� 42������ > 4�1�� ! �� 2� � 4� �71<� � �5� 5 724 � ;���4���9� �5�7���2����;� � ��5�42����������24�9� ���3 �� ���924 ���3 �� ���2��42������ > 4�1�2�� <�4 �;���42��� > 4�1��! �� 2� � 4�2��262�7���5 724�9�2� 4�9� ��< � 6���2������;� � ��5�42������2�� <�4 �<�������5��4�;���42��� > 4�1��! �� 2�4� �342����55�34� �9���4 �4� 2� � 4� 5 724�>2���� ��d�c�4� �����9� �5�7���2����;� � ��5�42������924 �<���;���42��� > 4�1��! ����?4�5 724�>2��������c�4� ����� 9� ��<4�2����5 �1�;���42���2��5��4� > 4�1�924 ���;� � ��5�42������5����9���<>���;� � ��5�42������ 924 �;���42���2��<��� > 4�1��%��4�;���42���924 ���;� � ��5�42��������6��4 ����9� 4�5 724�>2���������� 4� ������7��4����9�1�2 47 ��3��4��4��5�4 �� �2��9 23 �3�7 � ��� �>� 2;��2���������924 � 1���� � 2:�� �d� !2����������(���42���)> 4�1��5� ;�����, �; �� �5�5 724 ��7�421�4��>���9� �>2�����"��3� ���5�<���;���42��� > 4�1�;���4 � 7 626��2��1��>���> ��7��4�� � 3�;2��� �� �>� 5�7 � 5������ � �2�5����9 � �� �� ;���42��� 2�� 5��4� ;���4� ��1����9 ����� �>� �2�5���� �337 ���4� � 4�����5� � 6� 4�2��+� 3 �4���; 2���% �1�4 ��;�2�4��5�62�9�5 724� � 6� 4�2�������421�� ����24� ��; �4��2�3 �� ���5 724�>2������ ���� !�<����������*2��������>2�����44 2<74� ��5�37371<� �� ��55�34���<>��255� ��4�42������; �3423� �� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� ��;� � ��5�42������ ����� �����b� ����� ��;� � ��5�42������ d���� ������� ����� ��;� � ��5�42������ c���� ��d�c�� ����� �)'����d�� ����� $)� ���c� ���� !�<����������*2��������>2�����44 2<74� ��5�37371<� �� ��55�34���<>��255� ��4�;���42��� > 4�1�� ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2��<��� b���� �����b� ���d� (���42���2��5��4� > 4�1� d���� ������� �c��� !�4� 4� $)� m� m� � ! ��1���� 2��262�7��� 5 724�9�2� 4� �� � �+n�����)'n�������$n���9� � 2��2523��4�>�� ��4� � 4 ���:� ��� 4���nc�b��� 49��4�2�� ;n������; �62�2����62���3��4 �4�4 ��<���;���42���2 ��55�3426��2��2�3 �� ��2��262�7���5 724�9�2� 4�����dl�,��"���<�74�1���� 2��262�7���5 724�9�2� 4�2�3 �� ��2 �������������� � ! �� 1���� 5 724� >2���� �� � �+n��b��� )'n������� $n��� 9� � 2��2523��4�>� � ��4� � 4 ��� :� ��� 4���nd��b��49��4�2��;n������; �62�2����62���3��4 �4�4 ��<���;���42���2 ��55�3426��2��2�3 �� ��5 724� >2��������dl�,��"���<�74�1����5 724�>2����2�3 �� ��2 ����b��������� � !�<����������"�4� �342����5�;���42��� > 4�1�����42������; �3423� ����4 ��>2��������>2�����44 2<74� ��5� 37371<� � ! ��41��4 � $����5�5 724 � ;���4��� "��262�7���5 724�94�� ���� % 724�>2���� �4� ����� (���42���2�� <��� ��;� � ��5�42������ ��cc� ����d�� �d�d� ��;� � ��5�42������ d���� ����b�� ����� ��;� � ��5�42������ c�bb� ��b���� �d�c� (���42���2�� 5��4� > 4�1� ��;� � ��5�42������ ��bb� �������� ����� ��;� � ��5�42������ d���� ������� �c�b� ��;� � ��5�42������ c���� ��d��d� ���c� �)'����d�� ��c�� ����� ���d� ,���l�� ��cd� ������ ����� ���� �55�34 ��5�42��������� �2��1�2 47 ��55�34 ��5�42��������� �2��1�2 47 ��55�34 ��5�42��������� �2��1�2 47 ��55�34 ��5�42��������� �2��1�2 47 ����� ! �� �2��1�2 47 ��3��4��4�2� 2��2523��4�>�2�5�7��3����7��4���255� ��4�42����������;���42���1�4 �� � �%2��� ���� "�� 4 ��9 ���� � �92��� �� ���� 4 ��1�?2171� �2��1�2 47 ��9� � ��4��� ��� 5�7 � ;� � �5� 42������ > 4�1� 5����9���<>� 4 ������� 49��;� ��5� 42������ > 4�1���347���>� �2��1�2 47 ��� ��7���>� ��3 �� ��� 924 � 421��� ���2��� 2�� �� 4� �1;�2���� 4 � �� 9� � ��� 2��2523��4� �255� ��3�� �1���� 4 �� 42������ 4 ��41��4 � �7�� 4�� ��6>� �2�5���� 2�� 4 �� 1��4 � �5� +� 3 � ������ )�2�� 1�2 47 �� 3��4��4� 3 �������7��4��42������; �3423� ����� 2� � �1�2 47 ��3��4��4�9� ��< � 6���2��5�7 �;� ��5�42������ ; �3423�� �4�9 ���� � �92��� �� ����5� 4�1�4��� < 2�a���� <244� � ��7 �� ���� 37371<� �� ! � �� � 7�4 � �b� �� � ��4����� 9� �� 212�� �4������ 2��4����������������� �44��4������������ 4�4���4 �4� �2��1�2 47 ��3��4��4 �� �� 7< 4��42���>� 2� � �924 �3 2 ���;��92���4 ���12�2171�42������� � � ����'�4�'�4�'�4�'�4��������� %2������)�2��1�2 47 ��3��4��4��l���4��255� ��4�42����������;���42���1�4 ��� � ,������4����� ������� �;� 4��� 4 �4����;� 42������ 2�3 �� �� 4 �� �2��;� � 24>�����1��2;7��4�� 7 5�3�� �7� �� � 4�� 21; �6��9�4� � 2�4�0���+� � <��� ����, �7� 7 >� ����c���� ���< � 6��� 4 �4� ���;� 42������ ��3 �� ��� �2�� <7�0� ��� 24>� ����;���4 �42��� � 2 4��3�� 7;� 4�� 4 �� 42����� ��;4 ���� 31����� ��3�7 ���� ��4�� �94 �1� ��2��4 �����;� � �2����>� �����2�3 �� ��9�4� � ���2���3�;�324>�� � ,��3�7 2��,��3�7 2��,��3�7 2��,��3�7 2������ ���� �<�6�� 4 �� 47�>�� 24� 2 � ��4��� 4 �4� 3��� � 4 �4� �54� � !�� �1��� � 6� 4� 2�� 1��271� 2� � ����� 5� � � �92���7;�����3 �; ��7 2���� >� �� ���<���;���42��� > 4�1�924 �����;� � ��5�42������2 �4 ��<� 4� 1�4 ��� ���� 24 � � 3�;2��� 4 �� 42���� 7 ���� � �� �>� 5�� � 5������ �! ��1�?2171� �2��1�2 47 ��9� � ��4��������;� � ��5�42������ > 4�1�5����9���<>���������;� � �42������ > 4�1��!9��;� � � > 4�1� �9�����9�1�2 47 ��3��4��4��5�4 �� �2��9 23 �3�7 � ��� �>� 2;��2���������924 � 1���� �5 724� 2:�� 7�421�4��>���9� �>2������ � �30��9�����1��4�30��9�����1��4�30��9�����1��4�30��9�����1��4���� ���� ! �� � �� 3 �9� �3� 2����74�924 �4 ��52���32��� 7;;� 4��5�/ 2 2�&�<� ����%�7���42����/&%��� �������� ��� 237�47 ���-� �� 3 �,�7�32�����-,���' �0����������� �� ���� -�5� ��3� -�5� ��3� -�5� ��3� -�5� ��3� ���� ���� ��-,� ��������� � �� 237�47 ��� -� �� 3 � ,�7�32���� ���d�� %� 42�2:� � -�3�11����42��� &72������d�� ��-,��)�2� �(7<���$����d���������� ��� 2��-� �,�7�32���%� 1��4���' �0��� ��-"� ��������� � �� 237�47 ��� -� �� 3 � "� 42474���� ������ / 2 2� ( �a7042� .�4� ��2�� d4 � ��242���� �������� ��� 237�47 ���-� �� 3 �"� 42474���&�:2;7 ��������������� �� ��� !2����������(���42���)> 4�1��5� ;�����, �; �� � �44��-���/�����/ � ������ �)��� � ����������55�34��5� 42����������17�3 2������ >2�����5� 3� �� 2�� 4 �� 7<1��4����7 �2�5��� ��2����5�(7�a�<��"��2���"�4�������� 23���2����b����bo��c�� ���� 2�� ����+��+�::��32�2�� $�� )2�6� 4 2��+�� (���2�2��+�� �� <�52� 2��+�� �� 2�� ����+�� )�442��� ������ �55�34 ��5� �255� ��4� �2�� 42������ > 4�1 ���� �2�� ; > 23��� 3 � �34� 2 423 � ���� 3 �;� >2�����(�;� � ; � ��4����4�4 ��� ��,�����7 �;)�3�� ����(���6�� �26� 24>���<����(���6���"4��>���c���� )�;4�1<� �������� � 72>�� k��.����c��# ���23�1�44� � 4�47 � ����� ���23� �3>3�2��� 2���������� � �2� ��-� ��,�� � 6�� -�3>3���������������� ,�������������/��(��,��-����'��%��*7����(�����&�� ����)��!��) 2�26� ����&��'��)124 �������������9���� ������ )�2�� 1�����1��4� �;42�� � 5� � ��52 ��� 2�� 4 �� �12�� 2�� 4 �;23 �� ���7��� ���� ;� ���2��� 3 �;�; ��7342����)�2��!2������-� ��������d��d��� ,�<����� ��c��� �55�34� �5� 42������ ��� �2�� ; > 23��� ; �;� 42� ���� &2� ��� )�2�� '�;4�� ! �� %��� ��� �26� 24>��5�-2�� ����'��) ��(� 4������ ���� �:2��� +� � <����)�����+��-��, �7� 7 >�����c���55�34��5����;�42���������� �94 �����>2�����5�1�2:��7��� � 9�4� � 4 � �3���242����4��255� ��4�; > 2����23��� 4��� ����3�7 ��4�?47 ��� �2� �����"��2���)�3�� )�2��)32���b��dd��db��� +7 �� �� .�� ������ +2�� ��� �74 242��� �5� .2� � � ;���4 �� "� 42474�� �5� ;���4� �74 242���� �26� 24>� �5� .� �� �21��%��� ���-�;7<�23��5�&� 1��>��3���123�( � ��;;���b���d�� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � short communication bangladesh agron. j. 2015, 18(2): 105-109 waterlogging tolerance of soybean r. ara1, m. a. mannan1*, q. a. khaliq1 and m. m. uddin miah2 1department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh 2department of agroforestry and environmental, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding author: mannanbsmrau@yahoo.com key words: soybean, water logging tolerance, dry matter accumulation and yield. soybean (glycine max l.) is one of the most important oil crops and rich in protein which have various uses for human food. water logging induced several physiological disturbances in growth, dry matter, photosynthesis and pod formation that resulted in lower yield (solaiman et al., 2007; pociecha et al., 2008; celik and turhan, 2011; hasanuzzaman et al. 2016). waterlogging reduced seed yield primarily by reducing the number of pods per plant and pod setting (ahmad et al., 2003; ahmed et al., 2002). linkemer et al. (1998) identified some vegetative stages sensitive to waterlogging as well as some reproductive stages. soybean germplasms display a spectrum of waterlogging tolerance capability. the degree of flooding tolerance of soybean germplasms varies with the developmental stages. the present study was, therefore undertaken to evaluate the effect of excess water on dry matter accumulation and yield of soybean. a field experiment was carried out at the agronomy field, bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur during december, 2013 to april 2014. the treatments were four soybean genotypes viz. i) ags 313 ii) g 00351 iii) bd soybean 4 (bangladesh soybean 4) iv) g 00197 and three waterlogging i) control (no waterlogging) ii) waterlogging at r1 (blooming) stage iii) waterlogging at r4 (full pod) stages for one week. these four genotypes were screened out from 50 soybean genotypes at early stage waterlogging on the basis of relative shoot dry matter accumulation. the experiment was laid out in splitplot design with three replications where waterlogging treatments were assigned in main plot and four soybean genotypes to sub-plots. waterlogging plot area was surrounded by polythene anchored into the ground and extending 30 cm above the ground to hold water. seed of each soybean genotypes was sown in december 2013 maintaining 30 cm line to line and 5 cm plant to plant distance. after sowing of seeds, light irrigation was given to ensure uniform germination of seeds. control plots were irrigated at 30 and 50 das (days after sowing) all over the growing period. waterlogging treated plots were irrigated at blooming and full pod stages. water level of the each flooding treatments was maintained at 2.5 to 5.0 cm above ground every alternate day during the 7-day period. the plots were kept weed free. the experimental area was fertilized with 50, 160, 110, 100, 8 kg ha-1 urea, tsp, mop, gypsum and boron, respectively. the entire amount of tsp, mop, gypsum, boron and half of urea were applied as basal dose. rest urea was applied before flowering. necessary plant protection measures were taken to maintain optimum growth of the plants. at maturity five plants were randomly selected and plants were segmented into leaf, stem and roots and oven dried for 72 hours at 70o c. the observations on t dry matter per plant (including root), and yield attributes were recorded. seed yield was adjusted to 12% moisture content. the data recorded on different parameters were statistically analyzed and the differences between the treatments means were compared by lsd test (gomez and gomez, 1984). 106 ara et al. shoot dry weight of all soybean genotypes were significantly affected by waterlogging (fig. 1). reduction was higher when plant was subjected to waterlogging at r4 stage than r1 stage. the highest relative shoot dry matter (69.35%) was accumulated by genotype ags 313, while g00351 and bd soybean-4 produced only 66.97 and 65.29 %, respectively and the lowest (54.21%) in genotype g00197 (54.21%) at r4 stage of flooding. a similar trend in shoot growth was found when flooding treatment was imposed at r1 stage. the reduction in shoot dry matter is probably due to reduction in shoot length and branching. tolerant genotypes with vigorous shoot and root growth were better able to tolerate transient waterlogging (hartley et al., 1993). reduction in total dry matter (dm) production and the variation in dm production among genotypes due to waterlogging are in fig. 2. both r1 and r4 stages of waterlogging affected significantly the total dry matter production in all the soybean genotypes. total dry matter reduction due to waterlogging was lower at r4 stage than that at r1 stage. waterlogging induced differences in total dry matter production among the genotypes were caused by the differences in the reduction of root, leaf and stem dry matter than control. the minimum reduction in total dry matter was noticed in genotype ags 313 (31.05%), whereas the maximum (45.43%) in g00197 (fig. 2). the dry matter reduction in g00351 and bd soybean 4 were (34%) and (35%), respectively. the total dry matter in genotype ags 313 was less affected even at r1 stage waterlogging, which could be attributed to more efficient production of leaf, stem, and root dry matter. waterlogging generally reduced the growth of plant components resulting in low total dry weight (tdw). tolerant genotypes had more dry matter because they were lesser affected by waterlogging. the tolerant genotypes maintained greater root, shoot and leaf dry matter under waterlogging than the sensitive cultivars. waterlogging reduced significantly number of pods per plant compared to that in control in all the four soybean genotypes. the reduction was smaller at r1 stage waterlogging compared to that at r4 stage. in control treatment, bangladesh soybean 4 produced the highest number of pods per plant (85.86) while waterlogging treatment was imposed at r1 and at r4 stage was 66 and 53, respectively (table 1). the highest relative pods number per plant produced by genotype ags 313 which was 90.86 % at r1 stage and 84.78% at r4 stage of waterlogging. the highest relative pods per plant in genotype ags 313 might have attributed to a lower reduction in shoot dry matter as well as total dry matter. waterlogging 107 waterlogging tolerance of soybean also reduced the average number of seeds per pod significantly in all the soybean genotypes studied (table 1). the number of seeds per pod was affected a little by r1 stage flooding in all the genotypes. under r4 stage flooding, the highest relative seeds number per pod was produced by the genotype ags 313 (72.04%), followed by g 00351 (66.47%), bd soybean 4 (64.82%) and the lowest by g 00197 (59.25 %). the highest seeds number per pod in genotype ags 313 was probably due to the lowest reduction in pollen fertility due to waterlogging as reported by omae et al. (2005). waterlogging induced reduction in seeds per pod was higher at later stage waterlogging as reported by umaharan et al. (1997) and zhou and lin (1995). seed weight decreased significantly at r1 stage flooding, which further decreased at r4 stage (table 2). at r1 stage flooding, 100-seed weight ranged from 7.91 to 17.93g, whereas at r4 stage waterlogging from 5.81 g to 17.89 g. relative grain weight was the highest in ags 313 (87.06%), followed by g 00351 (82.25%) and bd soybean 4 (72.10%), and lowest in g 00197 (71.55%) at r4 stage waterlogging. a remarkable reduction in the size of seeds was observed at r4 stage water logging in all the genotypes. table 1. number of pods plant-1 and number of seeds pod-1 of four selected soybean genotypes as affected by waterlogging number of pods plant-1 number of seeds pod-1genotypes control flooding at r1 stage flooding at r4 stage control flooding at r1 stage flooding at r4 stage ags 313 28.46 25.86 (90.86) 24.13 (84.78) 1.86 1.52 (81.72) 1.34 (72.04) g 00351 20.53 17.06 (83.09) 12.93 (62.98) 1.73 1.32 (76.30) 1.15 (66.47) bd soybean 4 85.86 65.66 (76.47) 53.35 (62.21) 1.99 1.46 (73.33) 1.29 (64.82) g 00197 53.26 34.86 (65.45) 25.25 (47.40) 1.89 1.22 (64.45) 1.12 (59.25) lsd (0.05) 8.55 0.32 cv (%) 13.20 11.42 values in parenthesis indicates per cent of control seed yield was reduced by waterlogging in all the soybean genotypes studied and the decreasing rate was higher in r4 stage than r1 stage. seed yield of different genotypes ranged from 1.69 to 2.70 t ha-1 under normal conditions and that from 1.10 to 2.09 and 0.80 to 2.84 t ha-1 respectively under r1 and r4 stage flooding conditions. (table 2). the highest relative seed yield was found in genotype ags 313 at both the waterlogging stages and the lowest was genotype g 00197. the highest relative pod number per plant and individual seed weight in genotype ags 313 mostly contributed to the highest relative seed yield of this genotype. waterlogging reduced seed yield primarily by reducing the number of pod per plant and pod setting. the yield of soybean subjected to wet conditions at the vegetative growth stage may be reduced by 17–43% (oosterhuis et al., 1990; scott et al., 1990). genotypic sensitivity to waterlogging could be related to the level of endogenous plant hormones, which increase dropping of flowers and/or the loss of pod setting, as also observed in other crops (lakitan et al., 1992; umaharan et al., 1997) 108 ara et al. table 2. 100-seed weight and grain yield (t ha-1) of four selected soybean genotypes as affected by waterlogging 100 -seed weight (g) seed yield (t ha-1)genotypes control flooding at r1 stage flooding at r4 stage control flooding at r1 stage flooding at r4 stage ags 313 18.25 17.93 (98.24) 15.89 (87.06) 2.70 2.09 (77.40) 1.84 (68.14) g 00351 12.35 12.08 (97.81) 10.19 (82.25) 2.54 1.73 (68.11) 1.50 (59.05) bd soybean 4 7.60 7.30 (96.05) 5.48 (72.10) 2.28 1.50 (65.78) 1.12 (49.12) g 00197 8.12 7.91 (97.41) 5.81 (71.55) 1.69 1.10 (65.08) 0.80 (47.33) lsd (0.05) 0.92 0.36 cv (%) 14.77 12.17 values in parenthesis indicates per cent of control based on the study it may be concluded that waterlogged affects adversely the dry matter accumulation and yield of soybean plants and the reduction was higher at full pod stage flooding than in blooming stage flooding. the genotype ags 313 showed higher waterlogging tolerance while genotype g00197 was susceptible in terms of dry matter accumulation and yield performance. acknowledgement we are grateful to research management committee (rmc), bangabandhu sheikh mujibur rahman agricultural university for funding the research work. references ahmad, r., m. ikraam, e. ullah and a. mahmood. 2003. influence of different fertilizer levels on the growth and productivity of three mungbean cultivars. int. j. agric. biol. 5:335–338. ahmed, s., h. higuchi, e. nawata and t. sakuratani. 2002. effects on exogenous aba and ethylene application and waterlogging on photosynthesis in mungbean (vigna radiata l.cv. wilczak). j. trop. agric. 46:166–174. celik, g. and e. turhan. 2011. genotypic variation in growth and physiological responses of common bean (phaseolus vulgaris l.) seedlings to flooding. afr. j. biotechnol. 10:7372– 7380. gomez, a. a. and a. a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. pp.20-2015 hartley, r., r. lawn and d. byth. 1993. genotypic variation in growth and seed yield of soybean (glycine max l. merr.) in saturated soil culture. aust. j. agric. res. 44:689–702. hasanuzzaman, m., k. nahar, a, rahman, j.a. mahmud, m.s. hossain and m. fujita (2016) soybean production and environmental stresses. in: miransari m. (ed) environmental stresses in soybean production: soybean production, volume 2. academic press/elsevier inc., new york. usa. isbn: 978-0-12-801535-3 109 waterlogging tolerance of soybean lakitan, b., d. b. wolfe and r. w. zobel. 1992. flooding affects snap bean yield and genotypic variation in leaf gas exchange and root growth response. j. amer. soc. hort. sci. 117:711–716. linkemer, g., j. e. board and m. e. musgrave. 1998. waterlogging effects on growth and yield components in late-planted soybean. crop sci. 38:1576-1584. omae, h. a., y. kumar, k. egawa, kshiwaba and m. shono. 2005. genotypic differences in plant water status and relationship with reproductive responses in snapbean (phaseolus vulgaris l.) during water stress. jpn. j. trop. agric. 49: 1-7. oosterhuis, d. m., h. d. scott, r. e. hampton and s. d. wullschleger. 1990. physiological response of two soybean (glycine max l. merr.) cultivars to short-term flooding. environ. exp. bot. 30:85-92. pociecha, e., j. koscielniak and w.filek. 2008. effect of root flooding and stage of development on the growth and photosynthesis of field bean (vicia faba l. minor) acta physiol plant. 30:529–535. scott, h. d., j. de angulo, l. s. wood and d. j. pitts. 1990. influence of temporary flooding at three growth stages on soybean growth on a clayey soil. j. plant nutr. 13:1045-1071. solaiman, z., t. d. colmer, s. p. loss, b. d. thomson, and k. h. m. siddique. 2007. growth responses of cool-season grain legumes to transient water logging. aust j agric res. 58:406–412. zhou, w. and x. lin. 1995. effects of waterlogging at different growth stages on physiological characteristics and seed yield of winter rape (brassica napus l.) field crops res. 44:103–110. bangladesh agron. j. 2015, 18(1): 1-5 effect of sowing dates on the yield of sunflower bulbul ahmed1, mousumi sultana2, jesmin zaman3, santos kumar paul4, md. mokhlesur rahman5, md. rezaul islam6 and falguni majumdar7 1plant physiology division, bari, joydebpur, gazipur; 2tuber research sub-center, bari, seujgari, bogra 3department of agricultural extension, khamar bari, dhaka; 4agronomy division, bari, joydebpur, gazipur 5department of environmental science, jahangir nagor university, dhaka 6larsen chemical industries, dhaka and; 7department of agricultural extension, khamar bari, dhaka key words: sowing dates, yield and sunflower abstract the experiment was carried out at agronomy research field of bangladesh agricultural research institute (bari), joydebpur, gazipur and regional agricultural research station, hathazari, chittagong to find out optimum sowing date of sunflower during rabi season 2012-13. the sunflower var. bari surjomukhi-2 was used. five sowing dates; 10 november, 20 november, 30 november, 10 december and 20 december were tested. it was revealed that yield and yield attributes of sunflower were significantly influenced by sowing dates. the maximum plant height (172.13 cm), head diameter (18.33), weight of seed / per head (66 g), 1000seed weight (68 g) and yield (2.5 t ha−1) were obtained from 20 november sowing. the lowest yield (1.83 t ha−1) was obtained from 20 december sowing. the 20 november sowing received the higher duration for maturity (127 days), first flowering (57 days) and seed formation (20 days) while 20 december sowing showed shorter duration for maturity, first flowering and seed formation of 119, 54 and 14 days respectively. it was concluded that the 20 november sowing would be the optimum time of sowing for achieving maximum yield of sunflower. introduction sunflower (helianthus annuus l.) is one of the most important oil crop occupying the fourth place in the world, grown on 22 m ha in the world and producing about 33 million tons of sunflower seeds harvested around the world (fao, 2009). the sunflower is grown in the southern part of the country in a very limited scale. though its production is decreased due to increasing the rice area; it has bright future as the cropping intensity increasing day by day. in order to reduce the oil import, it is needed to increase oil seed production in our country. there are evidence that the sowing time has significant effect on the both seed yields and oil contents of sunflower under varying climatic conditions (johnson and jellum, 1972). sowing dates have also been found to greatly influence vegetative (emergence to first flowering time) and reproductive growth stages (flowering to pod maturity time) of crops (akther et al., 2013). when emergence rate for each sowing date was calculated using a common base temperature they were found to be well correlated with rate of change of day length. time of sowing determines time of flowering and it has great influence on dry matter accumulation, seed set and seed yield (sofield, 1977). to increase yield and its stability, it is necessary to take into consideration to determine the optimum sowing date for achieving higher yield of sunflower. 2 ahmed et al. materials and method the experiment was conducted at agronomy research field of bangladesh agricultural research institute (bari), joydebpur, gazipur and regional agricultural research station, hathazari, chittagong during the period from november 2012 to march 2013. four sowing dates viz. 20 november, 30 november, 10 december, and 20 december) were included in the study. the experiment was laid out in a rcb design with three replications. the soil was silty clay loam in texture belonging chhiata series (aez-28) of grey terrace soil having low organic matter (0.97%) and deficient in total nitrogen (0.056%), available phosphorus (12 ppm), exchangeable potassium (0.17 meq/100 g soil) and available sulpher (10 ppm). the var. bari surjamukhi-2 was used in this experiment. unit plot size was 5 m x 4.5 m. seeds of sunflower were sown in line with spacing of 50 cm x 25 cm. the experimental plots were fertilized by n92 k75 p40 s30 zn4 b1 kg/ha in the form of urea, triple super phosphate, muriate of potash, gypsum and zinc sulphate respectively. half of nitrogen and all of the fertilizers were applied at the time of final land preparation. rest half of nitrogen was applied in two equal splits at 2025 and 40-45 days after sowing (das). weeding, irrigation, earthling up and other intercultural operations were done as and when required. varying date of growth level, number of plant/ m2, plant height (cm), number of leaf/plant, leaf area/plant, head diameter (cm), no. of seed / head, thousand seed weight (g) and yield data was recorded. collected data were statistically analyzed by mstat-c and means were adjudged by lsd test. results and discussion joydebpur in joydebpur from the figure 1, it was found that at the first deca-day, the highest temperature was higher above 25 °c and the rainfall was highest 35 mm. there was no rainfall from the 2nd deca-day of november to till 1st deca-day of february. the temperature of that time was also reduced and as a result the plant growth was hampered due to low miosture of the soil. alter the 2nd deca day of january the temperature was increasing day by day and in the 2nd deca day of february it rainless than 5 mm. during the crop reproductive stages, in the 1st deca-day it was found that the temperature was increasing and in the 2nd deca day it was found the rainfall was 30 mm. the lowest temperature (10°c) was found in 1 st deca-day in january and eventually temperature the rainfall also reduced or not found. notwithstanding during the maturity period at the 2nd deca-day of apri, l the temperature was rised near to 35º c and the rainfall showed the highest. the shape of this function also describes temperature effects on most biological functions, including plant growth and development. the thermal dependence of the apparent reaction rate for selected enzymes may indicate the optimal thermal range for a plant. for crop plants, the thermal kinetic window (tkw) is generally established as a result of thermally induced lipid phase changes, rubisco activity and the starch synthesis pathway in leaves and reproductive organs (burke, 1990). the identification of tkws for different species can aid in the interpretation of the differential temperature stress responses for crop growth and development among species (burke, 1990). 3 effect of sowing dates on the yield of sunflower fig 1: deca-day minimum and maximum temperature and rainfall during rabi season of 2012-13 0 5 10 15 20 25 30 35 40 n o v 1 -1 0 n o v 1 1 -2 0 n o v 2 1 -3 0 d e c 1 -1 0 d e c 1 1 -2 0 d e c 2 1 -3 1 j a n 1 -1 0 j a n 1 1 -2 0 j a n 2 1 -3 0 f e b 1 -1 0 f e b 1 1 -2 0 f e b 2 1 -2 8 m a r 1 -1 0 m a r 1 1 -2 0 m a r 2 1 -3 1 a p r 1 -1 0 a p r 1 1 -2 0 a p r 2 1 -3 1 times t e m p e ra tu re 0 10 20 30 40 50 60 70 80 rainfall rainfall min temp max temp fig. 1: deca-day minimum and maximum temperature and rainfall during rabi season of 2012-2013 (source: bari weather center, 2012-13) it revealed from the table 1 that sunflower sown at 20 november sowing received the highest time (127 das) for maturity while lower at 20 december sowing (119 das). for seed formation 20 november sowing took the maximum days (20) whereas 20 december sowing took the minimum days (14). it might be due to the lower temperature from late december to mid january and at this time the vegetative growth was hampered due to low temperature and foggy weather condition. plants of 20 november sowing took the maximum time (57 days) for first flowering following 30 november sowing (56 days) and 20 december sowing received the minimum 54 days for first flowering. it might be due to increasing temperature from mid february to mid march. to complete the vegetative growth 20 november sowing received the minimum 46 days while the maximum 56 days was found at 20 december sowing. results revealed that late sown crop flowered earlier than those of early sown crop (table 1) which might be due to the fact that higher temperature reduced vegetative growth and enhanced flowering (summer et al., 1985, nihal 2010). similar trend was observed in 50% flowering as well as crop maturity. late sown crop matured about 7-10 days earlier than that of early sown crop. this was obvious as high temperatures increase rate of plant development (entz and fowler, 1991) and reduced length of the reproductive period (angadi et al., 2000). table 1. effect of sowing dates on the vegetative growth, first flowering, seed formation, and crop duration in sunflower, rabi season 2012-13 dates of sowing vegetative growth (days) 1st flowering (days) seed formation (days) crop growth duration (days) 10 november 20 november 46 57 20 127 30 november 55 56 14 126 10 december 55 56 15 123 20 december 56 54 14 119 4 ahmed et al. number of plant/m2, plant height, number of leaf/plant, head diameter, weight of seed per head, thousand of seed weight (g) and seed yields (t ha−1) were significantly influenced by sowing dates (table 2) except leaf area, number of seeds / head and plants/ m2. it also revealed that the highest plant height (172.13 cm) was found in november 20 sowing while the lowest (166.33 cm) in december 20 sowing. the highest head diameter (18.33 cm) was found in november 20 sowing while the lowest head diameter (13 cm) was in december 20 sowing. however, november 20 sowing showed the maximum number of seed/ head (935.33). the maximum weight of seed was found at november 20 sowing (66 g).the maximum weight of thousand seed was found at november 20 sowing (68 g) but statistically similar with november 30 sowing (64 gm). the maximum seed yield (2.5 t ha−1) was found with november 20 sowing followed by the november 30 sowing (1.83 t ha−1). seed yield generally decreased with delayed sowing which might be attributed to the decrease in yield components (siddique et al., 2002). reproductive development of many crop species may also be damaged by heat stroke imposing plants produce no flowers or set less number of grains with reduced size. table 2. effect of different sowing dates on the yield and yield attributes of sunflower sowing dates plants /m2 plant height (cm) number of leaf/plant (1st flowering) leaf area /plant head diameter (cm) no. of seeds/ head weight of seeds per head (g) 1000 seeds weight (g) seed yield (t ha−1) november 10 november 20 5.6 172.13 23.33 259.33 18.33 935 66 68 2.5 november 30 6.0 161.26 25.66 240.33 14.33 795 51 64 2.0 december 10 5.3 177.26 25.33 286.33 13.33 885 50 59 2.2 december 20 5.2 166.33 20 236.33 13 750 50 52 1.83 lsd (0.05) 0.85 17.85 7.80 ns 1.6 ns 10.29 6.87 0.56 cv (%) 9.75 6.84 21.47 18.46 7.06 9.54 12.33 7.36 17.17 table 3. effect of different sowing dates on the seed yield and yield attributes of sunflower date of sowing dry matter (kg) plant height (cm) head size (cm) no. of filled seeds/ head no. of unfilled seed/ head 1000 seed wt (g) seed yield (t ha−1) november 10 0.41 137.8 16.57 125.6 440.0 82.11 0.51 november 20 0.56 157.0 15.30 382.7 433.8 75.10 1.16 november 30 0.35 146.4 17.20 445.1 231.7 63.47 1.04 december 10 0.38 145.8 14.77 405.4 263.4 62.39 0.71 december 20 0.43 163.1 14.60 380.0 187.4 62.27 0.76 lsd (0.05 ) 0.14 ns 16.05 ns ns 13.93 0.25 cv (%) 18.4 6.23 16.05 23.94 24.80 10.72 16.45 hathazari, chittagong significant variation was observed due to varying sowing date in dry matter, head size, thousand seed weight, seed weight /plot, and yield (table 3).the highest dry matter (0.56 kg), 5 effect of sowing dates on the yield of sunflower plant height (157 cm) and seed weight per plant (32.33 g) was found with november 20 sowing while the lowest dry matter (0.43 kg), plant height (137.8 cm) and seed weight/ plant (10.63 g) was found with november 10 sowing. there was no significant identical difference in plant height obtained with november 20 and december 20 sowing. maximum number of unfilled seed (440.0) was received with november 20 sowing and lowest (187.4) with december 20 sowing. the highest thousand seed weight (82.11 g) was recorded in november 10 sowing and lowest (62.27 g) was recorded with december 20 sowing. the highest yield per plot (2.62 kg) and yield (1.16 t ha−1) was reordered in november 20 sowing, whereas the lowest yield (0.51 kg ha−1) was recorded in november 10 sowing. conclusion from the result it revealed that november 20 sowing would be the optimum sowing date for better seed yield of sunflower. references angadi, s. v., h. w. cutforth, p. r miller, b. g. mcconkey, entz m. h. s. a. brandt and k.m. volkmar. 2000. response of three brassica species to high temperature stress during reproductive growth. canadian j. plant sci. 80: 693-701. burke, j.j. 1990. high temperature stress and adaptation in crops. in: stress response in plants: adaptation and acclimation mechanisms. r.g. alscher and j.r. cummings (eds.). wiley, new york. pp. 295-309. entz, m. h. and d. b. fowler. 1991. agronomic performance of winter versus spring wheat. agron. j. 83: 527-532. nihal, k. 2010. response of lentil (lens culinaris medik.) to sowing date and timing of nitrogen application. j. food. agric. environ. 8 (2): 422-426. jonhson, b. j. and m.d. jellum. 1972. effect of planting date on sunflower yield, oil and plant characteristics. agron j. 64 (6): 747 siddique, a. b., d. wright and s.m.m. ali. (2002). effect of sowing dateson the phenology, seed yield and yield components of peas. online biol. sci. 2(5):300-303 sofield, k., l.t evans, m.g. cook and f. wardlaw. 1977. factors influencing the rate and duration of grain filling in wheat. aust. j. plant. physiol. 4:785-797 summer, f., r. j., e.h. roberts, w. erskine and r. h. killis. 1985. effects of temperature and photoperiod and flowering in lentils (lens culinaris medic.). ann. bot. 56(5): 659-671. microsoft word 8 bangladesh agron. j. 2017, 20(2): 75-80 performance performance performance performance of of of of system of rice intensificationsystem of rice intensificationsystem of rice intensificationsystem of rice intensification with with with with conventional method of rice cultivationconventional method of rice cultivationconventional method of rice cultivationconventional method of rice cultivation a. p. mondol, p. k. biswasa. p. mondol, p. k. biswasa. p. mondol, p. k. biswasa. p. mondol, p. k. biswas**** and m. s. islamand m. s. islamand m. s. islamand m. s. islam department of agronomy, sher-e-bangla agricultural university, dhaka1207 *corresponding author, e-mail: parimalbiswas@hotmail.com (received:received:received:received: 20 june 2017, accepted: accepted: accepted: accepted: 23 august 2017) key words: key words: key words: key words: sri, conventional method, boro season, rice varieties abstractabstractabstractabstract a field experiment was conducted in sher-e-bangla agricultural university research field of bangladesh during december 2012 to may 2013. this experiment was tested for two planting method consisting cm planting method (p1) and system of rice intensification (sri) planting method (p2) against five rice (oryza sativa) varieties named br 16 (v1), brri dhan29 (v2), brri dhan50 (v3), brri hybrid dhan2 (v4) and heera 4 (v5). the experiment was laid out in split-plot design with three replications. all yield parameters showed the highest for sri with higher effective tillers hill-1 (41.13), longer panicle (28.15 cm), higher total grains panicle-1 (216.89), number of filled grains panicle-1 (166.82) as a result 10.17and 12.5% higher grain yield and straw yield, respectively were observed in sri than the conventional method. introductionintroductionintroductionintroduction most of the asian countries accept rice as their staple food. asian countries cover near about 75% of the world’s rice supply (cabangon et al., 2002). sri is a rice cultivation method developed in madagascar which increase rice productivity with reducing the external inputs like fertilizers and herbicides (thakur et al., 2009 and vermeule, 2009). sustainable rice production would be possible by increasing yields on the same piece of land reducing the input like water, chemicals, fertilizers and labor (bouman et al., 2005; mati and nyamai, 2009). sri consists of some principles including transplanting of younger seedlings (< 15 days) at wider spacing in square grid pattern, only one seedling hill-1, water management with alternate wetting and drying, mechanical weeding and use of organic compost fertilizer instead of chemical fertilizer (stoop et al., 2002). use of younger seedlings, wider spacing and a single seedling hill-1 facilitate the utilization of the resource to develop stronger individual plants in the rice field. younger seedling in transplantation provide a longer vegetative growth period and single seedling reduce the competition and help to minimize the shading effect of lower leaves, as such lower leaves remain photosynthetically active for longer time and root activity remain higher for longer period as the supply of oxygen and carbohydrate to the root is increased (horie et al., 2005). supply of cytokinin to the lower leaves increase due to higher root activity, delay the senescence and help to maintain photosynthetic efficiency at the letter stage that result higher yield compared to cm (san-oh et al., 2006). but as awd is practiced in sri, it enhanced the supply of oxygen to the root zone that reducing the arenchyma and causing stronger, healthier root system to maximize the nutrient uptake (stoop et al., 2002). besides, the number of productive tiller is higher in sri (217%) over the cm (krishna et al., 2008). as such, the experiment was conducted to find out the proper method of sowing of rice in sri and compare to conventional method. 76 mondol et al. materials materials materials materials aaaand methodsnd methodsnd methodsnd methods this experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka-1207 with three inbreed rice varieties viz., br16, brri dhan29, brri dhan50 and two hybrid var. brri hybrid dhan4 and heera4 in two planting system(sri and cm). the experiment was accomplished in a split-plot design with three replications. a 34 day old seedlings were transplanted maintaining spacing 25 cm × 15 cm in cm with two seedlings hill1, where for sri, 16 day old seedlings with one seedlings hill-1. the unit plot size was 5m × 2.4m maintaining 30 cm × 30 cm spacing. two hand weddings were done for conventional plots, first at 16 days after transplanting followed by second at 15 days after first weeding. in sri plots, two hand rakings were done after hair line crack developed in the plots. in sri plots, alternate wetting and drying (awd) was practiced and in conventional plots continues flood irrigation was applied as per need of plants. the 46 % n containing urea was top-dressed in three equal installments at the rate of 260 kg ha-1 and 266 kg ha-1 for inbreed and hybrid, respectively. the first one after seedling recovery, second at vegetation stage and another at 7 days before panicle initiation. triple super phosphate (tsp), muriate of potash (mop), gypsum and zinc sulphate, (100, 120, 110 and 10 kg ha-1 ) for the inbreed varieties and 125, 120, 110, 15 kg ha-1 for the hybrid was applied as basal. all other intercultural operations were done as and when necessary. plants were infested with rice stem borer (scirphophaga incertolus) and leaf hopper (nephotettix nigropictus) to some extent which were successfully controlled by applying diazinone @ 10 ml/10 liter of water for 5 decimal lands and by furadan 5 g at the rate of 10 kg/ha. the grains were cleaned and sun dried to a moisture content of 14%. straw was also sun dried properly. the collected data were analyzed by using mstat-c package and the mean differences were adjusted by lsd test. results results results results aaaand discussionnd discussionnd discussionnd discussion number of effective and ineffective tillers hillnumber of effective and ineffective tillers hillnumber of effective and ineffective tillers hillnumber of effective and ineffective tillers hill----1111 the highest number of effective tillers hill-1 was produced in the planting method of sri than the conventional method (table 1) which was 250.04% higher than conventional method. among the variety, highest no. of effective tiller/plant was obtained from br16 (v1 ). in interaction showed that the variety br16 with sri gave highest tillers / plant than th other treatment. krishna et al. (2008) was also found 217% higher number of effective tillers in sri than cm. these might be due to use of tinny seedlings, wider spacing and efficient use of nutrients from the soil as the root system was well developed in sri. thakur et al. (2011) reported 38.5% increases in root length of sri over cm. wider spacing offered less interplant completion for resources. on the other hand, in sri seedlings are transplanted at two leaves stage (at third phyllochron), first tillering start at the fourth phyllochron (katayama,1951) that covers 40% of total tillering and get a chance of profuse tillering. as in cm transplanting is done after third phyllochron lead to a bigger loss in total tillers. ginigaddara and ranamukhaarachchi (2011) also supported that younger seedlings had ability to produce higher number of tillers hill-1 than older one. number of ineffective tillers hill-1 was higher in sri than the cm. this might be due to higher number of tertiary tillers in sri and most of the tertiary tillers inactive for production. 77 performance of system of rice intensification with conventional panicle lengthpanicle lengthpanicle lengthpanicle length sri produced significantly longer panicle (28.15 cm) than the cm (25.77 cm). panicle was 9.25% longer in sri than the conventional system (table 1). the v2 produced the longest panicle in sri (30.53 cm) that was followed by v5 (29.12 cm) in sri while v3 (23.52 cm) produced the shortest panicle in cm (table 1). among the interactions, p2v2 produced the longest panicle but all the five varieties produced longer panicle in sri than cm. biswas et al. (2013); thakur et al. (2011) and latif et al. (2005) also revealed the similar findings of higher panicle length in sri . longer panicle of sri might be due to higher dry matter accumulation in the plant, higher photosynthetic rate and better utilization of the nutrients. integration of limited irrigation and mechanical weeding in sri, increase the aeration by dissolving oxygen from the irrigation water enhancing the root: shoot ratio (uphoff and randriamiharisoa, 2002). total number of grains panicletotal number of grains panicletotal number of grains panicletotal number of grains panicle----1111 the higher number of grains panicle-1 was produced in the planting method of sri (216.89) than the cm (172.58). which was 25.67% higher in sri (table 1). each of the five varieties, v1, v2, v3, v4 and v5 produced 17.19, 25.63, 37.31, 22.24 and 26.25% higher grains panicle-1 in sri than cm (table 1). thakur et al. (2011) also agreed that sri produced higher number of total grains panicle-1 than standard management practice. bozorgi et al. (2011) suggested that wider spacing gave maximum number of grains panicle-1. filled filled filled filled grains paniclegrains paniclegrains paniclegrains panicle----1111 sri (166.82) produced significantly higher number of filled grains panicle-1 than the cm (124.41) (table 1) which was 34.09% higher in sri than the cm. maximum number of filled grains panicle-1 were produced by v5 (186.37) that was statistically similar with v2 (166.80), v3 (172.23) and v4 (182.97) in sri planting system followed by v2 (157.70) and v5 (133.77) in cm and minimum number of grains panicle-1 by v3 (92.37) in cm. these result reveled that sri produced higher filled grains panicle-1 than cm in respect of variety. higher number of filled grins panice-1 in sri might be due to maximum utilization of solar radiation, availability of nutrients on the root zone and better uptake of nutrients by the developed root system and long lasting lower leaves of each of the hill as photosynthetically active. ali et al. (2013) observed higher number of filled grain panicle-1 from 15 day old seedling with intermittent irrigation, which was two important principle of sri, than 30 day old seedling with continuous flooded plot. thakur et al. (2011) also obtained the similar result of filled grain panicle-1 in sri. weight of 1000weight of 1000weight of 1000weight of 1000--- grainsgrainsgrainsgrains the higher weight of 1000-grains (25.60 g) was obtained from cm and lower (24.13 g) from sri (table 1). the v5 produced maximum 1000grains weight in cm that was followed by v5 (29.24 g) in sri and v4 (28.64 g) in cm. minimum 1000grains weight was recorded for v3 (19.83 g) in cm that was statistically similar with v2 (20.67 g) and v3 (19.69 g) in sri (table 1). mannan et al. (2009) also opined that heavier grain weight was found in early planted crop and grain weight decreased with the delayed transplanting. grain yieldgrain yieldgrain yieldgrain yield sri produced significantly higher (10.17%) yield (9.10 t ha-1) than cm (8.26 t ha-1) (table 1). the v1, v2, v3, v4 and v5 produced 14.29, 8.31, 8.57, 10.22 and 9.70% higher grain yield in sri than the cm with the respective varieties (table 1). in sri, plant received longer growth duration as it was transplanted in very tiny stage whereas in cm transplanted in old aged with shorter time. due to longer vegetative growth, tiller production was higher in sri than cm that 78 mondol et al. ultimately leads to lower yield in cm. on the other hand, number of effective tillers hill-1, panicle length, number of total grains panicle-1, number of filled grains panicle-1 was higher in sri than cm which might be the reason of higher yield in sri. ginigaddara and ranamukhaarachchi (2011) assured that the transplanting with younger seedlings in water saving rice production system produced more effective tillers hill-1, filled grains plant-1, panicle length compared to cm. suganthi et al. (2003) suggested that delayed transplanting significantly reduced the number of productive tiller which reduced the grain yield. better yielding performance of sri might be due to higher net photosynthetic rate of the fully expanded leaves at mid-tillering and improved utilization of photosynthates in the grain-filling stage (song et al., 2013). krishna et al. (2008) also observed that sri produced 15.65% higher grain yield over traditional method. straw yieldstraw yieldstraw yieldstraw yield higher straw yield was produced in the planting method of sri (9.48 tha-1) than conventional method (8.85 tha-1) (table 1). the 12.19% higher straw yield was produced in sri than conventional method. among the interaction, v4 (10.02 t ha -1) produced maximum straw yield in sri that was statistically similar for v2 in sri (9.80 t ha -1) and cm (9.53 t ha-1) followed by v5 (9.36 t ha -1) in sri. the minimum straw yield was produced in cm by v3 (8.38 t ha -1) which was statistically similar for v1 (8.64 t ha -1), v4 (8.83 t ha -1) and v5 (8.85 t ha -1) in cm. the higher straw yield might be due to higher amount of biomass production in extended vegetative growth period than the late transplanting in cm (mannan et al., 2009). das (2003) found 39 and 12% higher straw yield in sri compared to the field practice. table 1. effect of planting method on yield contributing character of inbred and hybrid rice treatments effective tillers (no. hill-1) ineffective tillers (no. hill-1) panicle length (cm) total grains panicle-1 (no.) filled grains panicle-1 (no.) unfilled grains panicle1 (no.) 1000grains weight (g) grain yield (t ha-1) straw yield (t ha-1) p1 11.75b 4.33b 25.77b 172.58b 124.41b 48.17 25.60a 8.26b 8.85b p2 41.13a 11.60a 28.15a 216.89a 166.82a 50.07 24.13b 9.10a 9.48a lsd (0.05) 2.267 5.359 0.4 15.98 9.751 ns 0.889 0.619 0.25 v1 33.43a 6.67b 26.38 b 163.60c 123.30c 40.25b 25.97b 8.10d 8.87c v2 27.77c 4.17b 29.05a 229.40a 162.25a 67.10a 21.42c 8.64abc 9.67a v3 30.13b 6.00b 25.24c 173.00bc 132.30bc 40.70b 19.76d 8.52bc 8.75c v4 22.57d 7.83b 25.94bc 189.20b 150.17ab 39.05b 27.25b 9.16a 9.42ab v5 18.30e 15.17a 28.20a 218.60a 160.07a 58.48a 29.91a 8.97ab 9.11bc lsd (0.05) 2.169 4.897 0.8783 18.99 18.546 11.794 1.303 0.41 0.4596 p1v1 14.40e 3.67cd 25.72e 150.60ef 120.87d 29.73c 26.77c 7.56f 8.64ef p1v2 11.67ef 0.67d 27.57c 203.30c 157.70bc 45.60b 22.16d 8.30de 9.53abc p1v3 14.33e 8.00bc 23.52f 145.80f 92.37e 53.47b 19.83e 8.17e 8.38f p1v4 9.47f 3.67cd 24.77e 170.10ef 117.37de 52.73b 28.64b 8.71cde 8.83def p1v5 8.87f 5.67bcd 27.27c 193.10d 133.77cd 59.30b 30.58a 8.56cde 8.85def p2v1 52.47a 9.67bc 27.04c 176.50d 125.73d 50.77b 25.17c 8.64cde 9.10cde p2v2 43.87b 7.67bc 30.53a 255.40a 166.80ab 88.60a 20.67e 8.99bc 9.80ab p2v3 45.93b 4.00cd 26.96d 200.20c 172.23ab 27.93c 19.69e 8.87bcd 9.12cde p2v4 35.67c 12.00b 27.11c 208.30b 182.97ab 25.37c 25.86c 9.60a 10.02a p2v5 27.73d 24.67a 29.12b 244.00 a 186.37a 57.67b 29.24b 9.39ab 9.36bcd lsd (0.05) 3.067 6.925 1.242 26.85 26.228 16.679 1.861 0.58 0.65 p1 = conventional method, p2 = sri, v1 = br 16, v2 = brri dhan29, v3 = brri dhan50, v4 = brri hybrid dhan2, and v5 = heera 4 79 performance of system of rice intensification with conventional conclusionconclusionconclusionconclusion the present study showed that rice cultivation adopting sri (single seedling hill-1 and wide spacing) produced 10.17 % higher yield over the conventional method. moreover, in sri technique as very tiny seedlings was used that could be maintained easily in dapog seedbed and ready for transplanting in short time where it require 20 to 25 more in conventional method. besides, awd in sri was a water saving method with higher benefit. acknowledgementacknowledgementacknowledgementacknowledgement the authors are very thankful to bangladesh academy of science (bas) for providing the financial support to complete the research work. referencesreferencesreferencesreferences ali, m. s., m. a. hasan, s. sikder, m. r. islam and m. h. r. hafiz, 2013. effect of seedling age and water management on the performance of boro rice (oryza sativa l.) variety. the agriculturists. 11(2): 28-37. biswas, p. k., tohiduzzaman and t. s. roy, 2013. screening of rice varieties responsive to system of rice intensification (sri) in boro season. bangladesh agron. j. 16(1): 51-60. bouman, b. a., s. peng, a. r. castañeda and r. m. visperas, 2005. yield and water use of irrigated tropical aerobic rice systems. agric. water mngt. 74: 87-105. bozorgi, h. r., a. faraji, r. k. danesh, a. keshavarz, e. azarpour and f. tarighi, 2011. effect of plant density on yield and yield components of rice. world appl. sci. j. 12 (11): 20532057. cabangon, r. j., t. p. tuong and n. b. abdullah, 2002. comparing water input and water productivity of transplanted and direct-seeded rice production systems. agric. water mngt. 57: 11-31. das, l. 2003. varification and refinement of the system of rice intensification in selected areas of bangladesh. trial monitoring report. saef development group. ginigaddara s. g. a. and s. l. ranamukhaarachchi, 2011. study of age of seedlings at transplanting on growth dynamics and yield of rice under alternating flooding and suspension of irrigation of water management. recent res. sci. technol. 3(3): 76-88. horie, t., t. shiraiwa, k. homma, k. katsura, y. maeda and h. yoshida, 2005. can yields of lowland rice resume the increases that they showed in the 1980s? plant production science. 8: 251-272. katayama, t. 1951. ine mugi no bungetsu kenkyu (studies on tillering in rice, wheat and barley). yokendo publishing, tokyo, japan. krishna, a., n. k. biradarpatil, k. manjappa and b. b. channappagoudar, 2008. evaluation of system of rice intensification cultivation, seedling age and spacing on seed yield and quality in samba masuhri (bpt-5204) rice. karnataka j. agri. sci. 21(1): 20-25. latif, m. a., m. r. islama, m. y. alia and m. a. salequeb, 2005. validation of the system of rice intensification (sri) in bangladesh. field crops res. 93 (2-3): 281-292. 80 mondol et al. mannan, m. a., bhuiya, m. s. u., hossain, s. m. a. and akhand, m. i. m. (2009). study on phenology and yielding ability of basmati fine rice genotypes as influenced by planting date in aman season. bangladesh j. agril. res. 34(3): 373-384. mati, b. m. and m. nyamai, 2009. promoting the system of rice intensification in kenya: growing more with less water: an information brochure used for training on sri in mwea. http://www.imawesa.net/publications/training manuals/imawesa training manual5-sri notes. san-oh, y., t. sugiyama, d. yoshhita, t. ookawa, and t. hirasawa, 2006. the effect of planting pattern on the rate of photosynthesis and related process during ripening in rice plants. field crops res. 96: 113-124. song, c., z. xi, w. dangying, x. chunmei and z. xifu, 2013. influence of the improved system of rice intensification (sri) on rice yield, yield components and tillering characteristics under different rice establishment methods. plant prod. sci. 16(2): 191-198. stoop, w. a., n. uphoff, and a. kassam, 2002. a review of agricultural research issue raised by the system of rice intensification (sri) from madagascar: opportunities for improving system for resource poor farmers. agric syst. 71:249-274. suganthi, m., p. subbian and s. marimuthu, 2003. optimization of time of planting and nitrogen levels to hybrid rice (adtrh. madras agric. j. 339340. thakur, a. k., n. uphoff and e. antony, 2009. an assessment of physiological effects of system or rice intensification (sri) practices compared with recommended rice cultivation practices in india. expl agric 46: 77–98. thakur, a. k., s. rath, d. u. patil and a. kumar, 2011. effects on rice plant morphology and physiology of water and associated management practices of the system of rice intensification and their implications for crop performance. paddy water env. 9: 13–24. uphoff, n. and r. randriamiharisoa, 2002. reducing water use in irrigated rice production with the madagascar system of rice intensification (sri). in: bouman et al. (eds.). water-wise rice production (pp. 71-87). los baños: international rice research institute (irri). vermeule, m. 2009. more from less, from less to more. scaling up: dissemination of a rice cultivation technique. farming matters. amsterfoort, the netherlands p.3. bangladesh agron bangladesh agron. j. 2015, 18(1): 89-98 growth, yield and quality of wheat varities as affected by different levels of nitrogen h. mondal1, s. mazumder2, s. k. roy3, t. a. mujahidi4 and s. k. paul5 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2sher-e-bangla nagar adorsha mohila college, dhaka-1207, bangladesh, 3department of genetics and plant breeding, sher-e-bangla agricultural university, dhaka-1207, bangladesh 4plant breeding division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh 5agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. e-mail: kbdhimangshu88@gmail.com key words: wheat variety, nitrogen, protein, grain quality abstract a field experiment was conducted at the experimental field of sher-e-bangla agricultural university, dhaka, bangladesh during november 2012 to march 2013 to evaluate the response of three (3) wheat varieties viz., bari gom23, bari gom24 and bari gom25 under four levels of nitrogen fertilizer i.e, 75, 100, 125 and 150 kg n ha-1. the experiment was laid out in randomized complete block design (rcbd) with three replications. results showed that plant height, number of leaves plant-1, leaf length and dry matter content were significantly affected due to varieties and/or nitrogen levels. grains ear-1, number of fertile grains plant-1, 1000-grain weight, grain yield and harvest index were also significantly influenced by varieties and/or nitrogen levels. the value of all parameters studied in this experiment increased with increasing nitrogen levels up to 125 kg n ha-1 and thereafter decreased with fertilizer increasing level. combination results showed that bari gom-24 with application of 125 kg n ha-1 gave the maximum grain yield (4.71 t ha-1), harvest index (49.37 %) and protein content (10.88%). introduction wheat (triticum aestivum l.) is the first important cereal crop throughout the world and second in bangladesh. it is the leading cereal crop which ranks first both in area (21,360 thousand hectares) and production (5,76,317 thousand metric ton) of the world (fao, 2014). it is a staple food for about one billion in as many as 43 countries and provides about 205 of total food calories. it contains carbohydrate (78.1%), protein (14.7%), minerals (2.1%), fat (2.1%) and considerable proportion of vitamins (jahan. 2014). wheat is cool-loving crop and adopted for cultivation in regions with cooler climatic conditions whereas bangladesh lies in the warmer part of the world, however wheat is grown in the winter or cold season in bangladesh from november to march. although wheat is cultivated in a large area (0.453 million ha) in bangladesh but the average yield (3.03 t ha−1) of wheat is very low. the low yield of wheat may be due to various factors such as lack of varieties, good quality seed, untimely seedling, low fertilization, seed rate, sowing techniques etc. balanced fertilization and better cultural practices are needed for obtaining higher yield of wheat. nitrogen is one of the basic elements required for obtaining higher wheat yield. it is largely used in the synthesis of protein, chlorophyll and other vital compounds which are attributed to all physiological and biochemical processes of plants. the response to n fertilization varies according to location, climate, crops and their varieties, type and characteristics of the soil, rate, time of fertilizer application and its placement (mengel and kirkby, 1978). unlike the other major plant nutrient elements, nitrogen is the 90 mondal et al. most limiting one in most of the soils of bangladesh for sustenance of optimum plant growth. therefore, this nutrient is mostly added extraneously in order to supplement their deficiencies in soil for successful crop production. but the addition of nitrogen beyond optimum level affects plant performance adversely. on the other hand, nitrogen either as nitrate or ammonium form is very unstable in soil in its natural cycle. it is reported that split application of nitrogen is better than singles application for increasing yield of wheat (gravelle et al., 1989). top dressing and split application of nitrogen fertilizers at critical crop growth stages of wheat are now emphasized (singh, 1988) as it is more beneficial than applying as single dose at sowing (randhawa et al., 1976). however, the yield response varies with number of split and time of nitrogen application. hence, it would be a good effort to develop an effective schedule for nitrogen management for wheat crop by the way of quantity split and time of application. besides this, the quality of wheat is directly related to protein content. high grain protein level in wheat is an important consideration for human nutrition but the varieties grown in the country are of low to medium protein content (warsthorn, 1988). high grain quality required a steady nutrient supply. many authors have found that most of the nitrogen uptakement by wheat plants occur before anthesis (dhugga and waines, 1989; frank et al., 1989). hence, the application of nitrogenous fertilizer is important for increasing grain protein content of wheat. in bangladesh, very little research work has been done on the effect of nitrogen application on wheat grain protein content and to acknowledge no work seems to have been reported on its relation with grain yield, as regards of in view of the limited information on the aforesaid problems a study was therefore, undertaken to determine the response of wheat variety as influenced by different levels of nitrogen. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka-1207, during the period from november 2012 to march 2013. the experimental area is located at 23.41' n and 90.22' e latitude and at an altitude of 8.6 m from the sea level. the soil of the experimental field belongs to the tejgaon series under the agroecological zone, madhupur tract (aez28) and the general soil type is deep red brown terrace soils. the experiment was laid out in randomized complete block design (rcbd) with factorial arrangement and three replications. there are two sets of treatments in the experiment. factor a: variety (3), v1 = bari gom-23 (bijoy), v2 = bari gom-24 (prodip), v3 = bari gom-25 and factor b: nitrogen levels (4) n1 = 75 kg n ha-1, n2 = 100 kg n ha-1 , n3 = 125 kg n ha-1, n4 = 150 kg n ha-1. there were 12 treatment combinations. seeds were sown continuously in line on 19 november, 2012. the line to line distance was maintained at 20 cm. the form of n fertilizer was granular urea. the experimental plots were fertilized with p, k, s and b at the rate of 26-50-20-1 kg ha-1, respectively in the form of triple superphosphate (tsp), muriate of potash (mop), gypsum and boric acid, accordingly during final land preparation as basal dose. the fertilizer does was according to soil test basis. here k application was high than p to improve the grain quality. one third of nitrogenous fertilizer was incorporated in the soil at the time of final land preparation according to treatments. the remaining amount of nitrogenous fertilizer was applied as top dressing in two split doses at crown root initiation stage (20 das) and prior to spike initiation stage (55 das). two times weeding were done manually at 25 and 45 das. two irrigations were applied at the time of crown root initiation stage (20 das) and booting stage (55 das). excess water was drained out from the field. all other intercultural operations were done as per requirement. the crop was harvested on march 18, 2013. the necessary data were collected from ten selected plants from each plot in the field at 30 days interval and at harvest, and dry matter weight of plant was collected at 30 days interval from 91 growth, yield and quality of wheat varities as affected by different levels of nitrogen the sub-samples of 5 plants plot-1 uprooting from 2nd line and were oven dried until a constant level. final yield data were collected from undisturbed middle three rows in the center. the data obtained for different characters were statistically analyzed following the analysis of variance techniques by using mstat-c computer package programme. the significant differences among the treatment means were compared by least significant difference (lsd) at 5% level of probability (gomez and gomez, 1984). results and discussion plant height significant variation was recorded for plant height of wheat due to varieties at 90 das (table 1). the tallest plants were observed from v2, while the shortest plants were found in v1.on the other hand, due to nitrogen plant height of wheat varied significantly at 90 das. at 90 das, the tallest plants were observed from n3 and the shortest plants were found in n1. significant differences were also recorded for the interaction effect of varieties and nitrogen on plant height of wheat at 90 das. at 90 das, the tallest plants were observed from v2n3 and the shortest) plants were found in v1n1. similar results were found by (randhawa et al., 1976). table 1. effect of variety, nitrogen rate and their combination on plant height of wheat treatment plant height (cm) at 30 das 60 das 90 das variety v1 30.58 c 61.33 c 90.79 c v2 37.17 a 69.14 a 95.85 a v3 33.72 b 65.39 b 93.05 b lsd(0.05) 3.063 3.050 2.604 nitrogen level n1 35.33 63.37 d 89.17 d n2 34.89 66.61 c 92.15 c n3 38.33 72.78 a 98.77 a n4 36.33 69.70 b 95.20 b lsd(0.05) ns 3.063 2.945 variety x nitrogen level v1n1 22.67 h 57.78 i 82.18 g v1n2 32.67 f 60.89 h 92.14 ef v1n3 32.67 f 65.45 e 93.18 de v1n4 33.33 e 63.00 g 91.76 f v2n1 34.67 d 68.33 c 93.17 de v2n2 40.67 b 67.55 d 96.04 b v2n3 42.00 a 72.45 a 99.85 a v2n4 34.33 d 70.22 b 94.12 d v3n1 38.67 c 67.67 d 92.14 ef v3n2 31.67 g 67.22 de 95.41 c v3n3 32.67 f 63.00 g 93.74 d v3n4 32.67 f 63.89 f 93.43 d lsd(0.05) 0.126 0.341 1.208 cv (%) 7.59 4.32 5.94 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25, n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha-1. 92 mondal et al. number of leaves per plant statistically significant differences were recorded for number of leaves plant-1 of wheat due to different varieties. at 90 das, the maximum number of leaves plant-1 was found from v2 and the minimum number of leaves plant-1 was observed from v1 (table 2). different nitrogen levels were significantly affect on number of leaves plant-1 of wheat at 90 das and the highest (number of leaves plant-1 was recorded from n3 whereas, the lowest number of leaves plant-1 was found from n1 (table 2). significant variation was also recorded due to combined effect of varieties and different nitrogen levels in terms of number of leaves plant-1 of wheat at 90 das and the maximum number of leaves plant-1 was observed from v2n3 whereas, the lowest number of leaves plant-1 was found from v1n1. table 2. effect of variety, nitrogen rate and their combination on number of leaves plant-1 of wheat treatment number of leaves plant-1 at 30 das 60 das 90 das variety v1 3.03 c 3.08 c 3.11 c v2 5.03 a 5.14 a 5.17 a v3 4.08 b 4.09 b 4.22 b lsd(0.05) 0.4421 0.2172 0.1709 nitrogen level n1 3.11 c 3.56 d 4.00 d n2 4.01 b 4.40 b 4.62 b n3 5.00 a 5.11 a 5.15 a n4 4.03 b 4.07 c 4.15 c lsd(0.05) 0.8270 0.1930 0.2895 variety x nitrogen level v1n1 2.67 j 3.00 f 3.02 i v1n2 3.00 i 3.l1 e 3.21 g v1n3 3.34 g 3.11 e 3.20 g v1n4 3.11 h 3.11 e 3.11 h v2n1 4.64 d 5.04 b 5.11 c v2n2 5.20 b 5.05 b 5.22 b v2n3 5.31 a 5.35 a 5.45 a v2n4 4.97 c 5.05 b 5.11 c v3n1 4.05 f 4.11 c 4.11 e v3n2 4.05 f 4.11 c 4.00 f v3n3 4.16 e 4.00 d 4.11 e v3n4 4.15 e 4.11 c 4.33 d lsd(0.05) 0.043 0.045 0.041 cv (%) 2.49 5.93 3.20 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25, n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha-1. 93 growth, yield and quality of wheat varities as affected by different levels of nitrogen leaf length (cm) statistically significant differences were recorded for leaf length due to different wheat varieties and different level of nitrogenous fertilizer and also for the combination of variety and different nitrogen rate at 90 das (table 3). the highest leaf length was found from v2 and the lowest leaf length was observed from v1 while due to the application of different dose of nitrogen the highest leaf length were observed from n3 whereas, the shortest leaf length was found from n1 and due to the combined effect of varieties and nitrogen the maximum leaf length were observed from v2n3 whereas, the lowest were found from v1n1. table 3. effect of variety, nitrogen rate and their combination on leaf length of wheat treatment leaf length (cm) at 30 das 60 das 90 das variety v1 19.96 c 26.24 c 28.43 c v2 23.72a 30.25 a 31.22 a v3 21.53 b 28.33 b 30.03 b lsd(0.05) 1.209 1.844 1.111 nitrogen level n1 21.82 c 26.92 c 27.13 c n2 23.20 b 28.52 b 29.44 b n3 24.30 a 29.92 a 31.44 a n4 23.04 b 28.55 b 29.22 b lsd(0.05) 1.076 1.273 1.630 variety x nitrogen level v1n1 17.06 j 25.67 i 26.71 h v1n2 20.11 h 27.33 f 28.52 f v1n3 21.45 f 28.22 e 29.84 d v1n4 21.11g 26.22 g 27.29 g v2n1 22.78 c 31.11 b 31.90 b v2n2 24.22 b 28.78 d 29.26 d v2n3 24.78 a 32.33 a 32.51 a v2n4 21.89 e 31.00 b 31.11 c v3n1 22.56 c 28.22 e 28.45 f v3n2 22.22 d 27.00 f 29.23 e v3n3 17.89 i 29.55 c 31.73 b v3n4 21.00 g 29.11 c 30.71 c lsd(0.05) 0.418 0.688 0.223 cv (%) 7.49 7.03 3.40 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25, n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha-1. dry matter content (g plant-1) significant differences were recorded for dry matter content in plant of wheat due to different varieties and nitrogen levels, and also due to their combination effect at 90 das (table 4). the maximum total dry matter in wheat plant were recorded from v2, whereas the lowest were in 94 mondal et al. v1 on the other hand at 90 das, the highest dry matter in plant were recorded from n3, whereas the lowest were found in n1. in case of combination effect the highest dry matter were observed from v2n3, whereas the lowest were found in v1n1. table 4. effect of variety, nitrogen rate and their combination on weight of dry matter (g plant-1) of wheat treatment dry matter (g plant-1) at 30 das 60 das 90 das variety v1 2.04 c 9.33 c 12.79 c v2 3.98 a 12.14 a 17.85 a v3 2.79 b 10.39 b 14.05 b lsd(0.05) 0.103 1.050 1.627 nitrogen level n1 2.33 d 7.37 d 13.17 d n2 2.89 c 9.31 c 14.15 c n3 4.33 a 11.78 a 17.77 a n4 3.33 b 10.60 b 15.20 b lsd(0.05) 0.037 1.089 1.945 variety x nitrogen level v1n1 1.75 i 8.56 i 10.38 j v1n2 2.01h 9.19 g 11.39 i v1n3 2.04 h 10.38 e 15.20 e v1n4 2.34 gh 9.20 g 13.79 g v2n1 2.77ef 10.27 e 15.70 e v2n2 3.59 c 11.39 e 17.49 c v2n3 4.98 a 14.04 a 19.49 a v2n4 3.74 b 13.09 b 18.67 b v3n1 2.37 g 8.97 h 11.99 h v3n2 2.79 ef 9.59 f 14.30 f v3n3 3.04 d 12.03 c 16.59 d v3n4 2.85 e 10.99 d 13.29 g lsd(0.05) 0.028 0.292 0.638 cv (%) 1.94 1.20 1.38 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25, n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha grains ear-1 number of grains ear-1 was significantly influenced by varieties, different nitrogen rate and also their combination (table 5). the maximum grains ear-1 (17.47) in wheat plant was recorded from v2, whereas the minimum (16.17) were found in v1. due to different nitrogen fertilizer application the maximum (17.60) grains ear-1 in wheat plant was recorded from n3, whereas the minimum (16.29) were found in n1. in case of combination effect the highest (18.24) grains ear-1 was observed from v2n3, whereas the lowest (15.57) were found in v1n1 95 growth, yield and quality of wheat varities as affected by different levels of nitrogen number of fertile grains plant-1 variation in fertile grains plant-1 among the studied varieties was statistically significant (table 5). the highest (54.69) number of fertile grains plant-1 was observed in v2 whereas, the lowest (45.55) was v1. results also showed that number of fertile grains plant-1 increased with increasing nitrogen levels and thereafter decreased by gradually increased the nitrogen levels. the highest (52.85) number of fertile grains plant-1 was recorded at n3 whereas, the lowest (48.63) was n1. the interaction effect of variety and nitrogen levels in relation to number of fertile grains plant-1 gave the highest (59.67) number of fertile grains plant-1 was observed in v2n3 and the lowest (40.33) was recorded in v1n1. number of unfertile grains plant-1 variation in number of unfertile grains plant-1 among the studied varieties was statistically significant (table 5). the highest (7.36) number of unfertile grains plant -1 was observed in v1 whereas, the lowest (3.00) was recorded in v2. from table 5 it is also observed that unfertile grains plant-1 decreased with increasing nitrogen and thereafter increased by gradually increased the nitrogen levels. the highest (6.45) unfertile grains plant-1 was observed n1 and the lowest (5.63) number of unfertile grains plant -1 was recorded in n3. the interaction effect of different variety and nitrogen levels in relation to number of unfertile grains plant -1 was also statistically significant. the highest (7.89) number of unfertile grains plant -1 was observed in v1n1 and the lowest (2.05) was recorded in v2n3. 1000-grain weight a significant difference in 1000-grain weight was also observed in studied varieties of wheat. the highest (54.95 g) 1000-grain weight was recorded in v2. in contrast, the lowest (50.91 g) 1000-grain weight was recorded in v1. genotypic variation in 1000-grain weight was also observed by many researchers in wheat (ghosh et al., 1991; bisht et al., 1999; hassan, 2006; chowdhury, 2008) that also conformity with the present experimental result. the highest (53.92 g) 1000-grain weight was recorded in n3 whereas, the lowest (49.82 g) 1000-grain weight was recorded in n1. in case of combination, the highest 1000-grain weight was recorded in v2n3 (57.60 g) whereas, the lowest (48.97 g) 1000-grain weight was recorded in v1n1. grain yield (t ha-1) variety had significant effect on grain yield of wheat (table 5). the highest (4.61 t ha-1) grain yield was recorded in v2 whereas; the lowest (3.45 t ha-1) was recorded from v1. nitrogen had also significant effect on grain of wheat. results showed that grain yield increased with increasing nitrogen rate and thereafter decreased by gradually increased the nitrogen. the highest (4.77 t ha-1) grain yield was recorded in n3 whereas, the lowest (3.20 t ha-1) were recorded from n1. the interaction effect of variety and nitrogen on grain yield was significantly differ. in case of unit area, v2n3 produced the highest (4.71 t ha-1) grain yield. in the interaction effect, v1n1 was produced the lowest (3.23 t ha-1) grain yield. straw yields (t ha-1) the straw yield showed significant differences among the studied varieties (table 5). bari gom23 produced the highest (5.92 t ha-1) straw yield. on the other hand, bari gom-24 produced the lowest straw yield (5.02 t ha-1). on the other hand the highest (6.03 t ha-1) straw yield was 96 mondal et al. recorded in n1 whereas, the lowest (4.83 t ha-1) was recorded in n3. the interaction effect of variety and nitrogen in relation to straw yield was also significant. the highest (6.11 t ha-1) straw yield was observed in v1n1 and the lowest (4.83 t ha-1) was recorded in v2n3. harvest index (%) variation in harvest index among the studied varieties was statistically significant (table 5). the highest (47.87 %) hi was recorded in bari gom-24 whereas, the lowest (36.82 %) harvest index was observed in bari gom-23. on the other hand in case of nitrogen rate the highest (49.68 %) hi recorded in n3 whereas, the lowest (34.67 %) harvest index was observed in n1. the interaction effect of variety and nitrogen in relation to hi was also statistically significant. results showed that the highest (49.37%) hi was found in v2n3 and the lowest in v1n1 (34.58 %) due to the combination of variety and nitrogen dose. table 5. effect of variety, nitrogen rate and their combination on yields and yield components of wheat treatment grains ear-1 no. of fertile grains plant-1 no. of unfertile grains plant-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) variety v1 16.17 c 45.55 c 7.36 a 50.91 c 3.45 c 5.92 a 36.82 c v2 17.47 a 54.69 a 3.00 c 54.95 a 4.61 a 5.02 c 47.87 a v3 16.88 b 49.83 b 5.89 b 52.47 b 4.00 b 5.32 b 42.92 b lsd(0.05) 0.4941 3.994 1.488 1.529 0.5271 0.2798 3.945 nitrogen level n1 16.29 d 48.63 c 6.45 a 49.82 d 3.20 d 6.03 a 34.67 d n2 16.81 c 51.89 b 6.37 b 51.59 c 4.10 c 5.67 b 41.97 c n3 17.60 a 52.85 a 5.63 d 53.92 a 4.77 a 4.83 d 49.68 a n4 17.20 b 52.07 b 5.89 c 52.90 b 4.40 b 5.24 c 45.64 b lsd(0.05) 0.2390 0.627 0.079 0.943 0.2703 0.3378 2.849 variety x nitrogen level v1n1 15.57 i 40.33 j 7.89 a 48.97 j 3.23 j 6.11 a 34.58 j v1n2 17.22 d 51.78 e 7.11 b 52.55 e 3.53 i 5.39 f 39.57 f v1n3 16.15 f 43.33 i 7.11 b 49.90 i 3.32 g 5.84 c 36.25 h v1n4 15.81 f-h 45.44 h 7.11 b 50.00 h 3.76 h 5.91 b 38.88 g v2n1 16.74 e 53.55 cd 2.89 g 56.84 b 4.66 b 5.61 e 45.38 c v2n2 17.13 d 54.00 b 4.33 e 53.20 d 4.46 d 4.95 h 47.39 b v2n3 17.75 bc 59.67 a 2.05 h 57.60 a 4.71 a 4.83 j 49.37 a v2n4 18.24 a 52.55 d 3.00 f 52.59 e 4.01 f 4.90 i 45.00 c v3n1 17.58 c 49.44 f 6.22 c 50.93 g 4.39 e 5.80 c 43.08 d v3n2 16.07 f 49.89 f 5.11 d 51.57 f 4.58 c 5.78 d 43.08 d v3n3 17.95 b 53.78 c 6.00 c 53.82 c 3.30 g 5.73 d 35.48 i v3n4 15.90 fg 46.55 g 5.78 c 53.37 d 3.81 g 5.19 h 42.33 e lsd(0.05) 0.288 0.988 0.575 0.557 0.054 0.060 1.03 cv (%) 3.74 2.09 5.40 4.03 9.47 7.29 5.40 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25, n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha 97 growth, yield and quality of wheat varities as affected by different levels of nitrogen protein content (%) variation in protein (%) among the studied varieties was statistically significant (figure 1). the highest protein content was recorded in bari gom-24 (10.64 %) whereas, the lowest protein content was observed in bari gom-23 (9.82 %) v1= bari gom-23, v2=bari gom-24 and v3=bari gom-25. fig. 1. effect of varieties on protein (%) of wheat (lsd0.05 = 0.0045) n1=75 kg n ha-1, n2 = 100 kg n ha-1, n3 -= 125 kg n ha-1and n4 = 150 kg n ha-1. fig.2. effect of nitrogen on protein (%) of wheat (lsd0.05 = 0.0072) the effect of nitrogen on protein (%) was statistically significant (figure 2). result revealed that the highest (10.27 %) protein content recorded in n3 whereas, the lowest (10.11 %) protein was observed in n1. the combination effect of variety and nitrogen in relation to protein (%) was also statistically significant (table 6). results showed that the highest (10.88 %) protein was recorded in v2n3 and the lowest (9.53 %) was in v1n1 . table 6. combination effect of varieties and nitrogen on protein (%) of wheat treatments protein (%) v1n1 9.53 e v1n2 10.05 c v1n3 10.54 b v1n4 9.85 de v2n1 10.05 c v2n2 10.62 b v2n3 10.88 a v2n4 10.04 c v3n1 9.89 c-e v3n2 9.81 e v3n3 10.02 cd v3n4 10.52 b lsd(0.05) 0.1713 cv (%) 4.38 in a column means having similar letter (s) are statistically similar and those having dissimilar letter(s) differ significantly by lsd at 0.05 levels of probability v1–bari gom-23, v2–bari gom-24 and v3–bari gom-25 n1–75 kg n ha-1, n2 100 kg n ha-1, n3 125 kg n ha-1and n4 150 kg n ha-1. 98 mondal et al. conclusion based on the results of the study it can be concluded that cultivating bari gom-24 coupled with application of 125 kg n ha-1 will be a promising practice for good yield also for higher protein content of wheat. however, to reach a specific conclusion and recommendation, more research work on different varieties and rate of nitrogen should be done over different agroecological zones. references bisht, p. s., p. c. pandey and p.lal. 1999. plant population requirement of wheat in the tarai region of uttar pradesh, india. int. rice res. notes. 24: 38. chowdhury, a. h. 2008. effect of row spacing on morpho-physiological characters and yield of wheat. m. s thesis, dept. crop bot., bangladesh agric. univ., mymensingh. dhugga, s. c. and d. s. waines 1989. evaluation of fertilizer and seed rate in wheat (triticum aestivum l.) under different tillage condition after transplanting rice (oryza saliva). indian j. agril. sci.70: 574-576. fao 2014. statistic yearbook. food and agriculture organization, rome, italy.79: 23-34. frank, n. g., s. c. dhugga and i. n. frolov 1989. the role of sowing depth in the formation of spring wheat yield.sibirskii vest selskokhozy aistvennoi nsuki 1:3-6. ghosh, b. c., c. v. raghavain and m. k. jana, 1991. effect of spacing and nitrogen on growth and yield of wheat. indian j. agron. 36: 227-230. gomez, k. a. and a. a. gomez 1984. statistical procedure for agricultural research. second edn. intl. rice res. inst., john wiley and sons. new york. pp. 1-340. gravelle, a. s. m. h. m., a. sufian, , j. m. dxbury, j. g. lauren, and c. a. meinser 1989. effect of tillage options and seed rate on grain yield of wheat. j. subtrop. agric. res. dev.2(3): 57-62. hassan, m. m. 2006. effect of row spacing and weeding regime on the growth and yield of wheat. m. s. thesis, dept. agron., bangladesh agril. univ., mymensingh. p. 42. jahan, m. a. h. s.. 2014.effect of different weed control methods in wheat. research report of wheat research centre.42-46. mengel, j. k. and y. k. m. a. kirkby. 1978. effect of sowing density on yield, yield components and grain quality in new spring wheat lines and varieties. biuletynlnstutui hodowli.44 (1 & 4): 185-236. peterson, r. f. 1965. wheat. int. sci. pub. inc., new york. p.258. randhawa, s. s., i., b. pandey, and s. s. mishra, 1976. effect of organic manure, fertilizer level and seed rate on yield and quality of late sown wheat (triticum aestivum l). indian j. agron. 44(4): 754-759. razzaque, m. a. and a. b. s.hossain. 1990. the wheat development programme in bangladesh.wheat for the non traditional warm areas. proc: intl. conf. cimmyt. mexico. pp. 44-54. singh, c. s. and u. n. singh. 2002. effect of nitrogen and sulphur nutrition on growth and yield of rice (oryza sativa l.) cultivars. res. crops. 3(3): 645-646. warsthorn, r. 1988. comparative performance of different-sized grain derived from wheat seed. am. j. wheat res. 63(5): 241-249. phenological performance in relation to yield of wheat genotypes“baw 1051, baw 1120 and baw 1141 were evaluated under normal and heat stress environments bangladesh agron. j. 2015, 18(1): 13-25 effect of terminal high temperature imposed by late sowing on phenological traits of wheat m. ilias hossain1, m.r.i mondal2, m. j. islam3, m a hakim4 and m.k. sultan5 1senior scientific officer (agronomy), 3scientist officer, regional wheat research centre, bari, rajshahi 2director general, 5director (research), bangladesh agricultural research institute, gazipur 4senior scientific officer, wheat research centre, bari, dinajpur corresponding author e-mail: iliasrwrc@gmail.com key words: sowing dates, wheat genotypes, temperature, phenological traits & yield abstract phenological performance in relation to yield of wheat genotypes; bari gom 26, baw 1051, bari gom 27 and bari gom 28 were evaluated under normal and heat stress environments. one irrigated timely sowing (its) and three irrigated late sowings (ils) were imposed to provide terminal high temperature over the tested genotypes. the its was november 25 and three ils were december 10, december 25 and january 10. in heat stress condition, the genotypes phased a significant level of high temperature stress which affected on phenological stage and yield compared to its. in its situation, days to anthesis and booting decreased in heat stress condition regardless the cultivars. the phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower grain yield as compared to normal condition. in heat stress situations (dec 10–jan 10), the average grain yield was reduced by12.8 39.8 % in bari gom 26, 14.4-29.7% in baw 1051, 11.5-26.5% in bari gom 27 and 17.4-25.6 % in bari gom 28 in both the season. it was also observed that grain yield was found to be reduced by about 7.7-15.4% in bari gom 26, 9.4-15.7 % in baw 1051, 9.4-12.4% in bari gom 27 and 9.7-12.0% in bari gom 28 from its for each 1°c rise in average mean air temperature during booting to maturity. on the other hand, reduction percent were less for the new varieties. grain yield reduction was about 1.4 2.65% in bari gom 28, 0.1-6.7 % in bari gom 27 and 1.7-6.0% in baw 1051. introduction developing heat tolerant wheat variety is a demand of the hour in bangladesh due to global warming or climate change. it is known to all that wheat seed sowing optimum time is from 15 november to 30 november in the country whether in northern part of bangladesh is up to 7 december due to cool weather compared to that of other parts of the country. generally, the farmer of the country cultivates wheat in winter season after harvesting of t. aman rice. but due to adverse weather farmers cannot transplant t. aman rice timely, ultimately harvests delayed. so, it is not possible for farmers to sow wheat seed timely. most of the farmers sow wheat seed on december, even in later i.e in january. late sowing wheat genotypes faced high temperature. as a result, heat stress due to late sowing beyond certain limits lowers the grain yield significantly. researchers have pointed out that wheat yield is considerably affected by sowing date (chio et al., 1992; liszewski, 1999; michiyama et al., 1998; pecio and wielgo, 1999). in fact, due to variation of sowing date the ambient temperature vary widely which affects the phenology of any crop plant. temperature is a modifying factor in all stages including germination, tillering, booting, ear emergence, anthesis and maturity since it can 14 hossain et al. influence the rate of water supply and other substrate necessary for growth (wanjura and buxtor, 1972). under the high temperature, the wheat crop completes its life cycle much faster than under normal temperature conditions (fischer, 1985). plant responses to high temperature vary with plant species, variety and phenological stages. reproductive processes are markedly affected by high temperatures in most plants, which ultimately affect fertilization and post-fertilization processes leading to reduced crop yield (wahid et al., 2007). thus, for crop production under high temperatures, it is important to know the developmental stages and plant processes that are most sensitive to heat stress as well as whether high day or high night temperatures are more injurious. in such context, wheat research centre, bari is supposed to develop high yielding wheat variety (hyv) considering their suitability in the existing cropping systems or environment. accordingly, wrc developed some suitable variety (s) having heat tolerant which can be grown after harvest of t. aman. as plant responses to high temperature vary with plant species, variety, location and phenological stages, it is essential to observe the performance of the promising or advanced genotypes of wheat in respect of phonological traits. considering the views in mind, the trial was undertaken to find out heat tolerant suitable variety (s) of wheat with its suitable sowing times in adverse climate condition with higher yield. materials and methods the experiment was carried out in the rabi season of 2012-13 and 2013-14 in research field of regional wheat research centre, rajshahi of bangladesh agricultural research institute. the soil of the experimental field of rajshahi belongs to aez # 11 characterized by flood free highland, fine in texture (sandy loam and silty loam) and poor in organic matter content. the experiment was laid out in split-plot design with 3 replications. three wheat varieties and one advanced genotypes (v1: bari gom 26, v2: baw 1051, v3: bari gom 27 and v4: bari gom 28) and bari gom 26 was used as test crop. one irrigated timely sowing (its) and three irrigated late sowings (ils) were imposed to provide terminal high temperature over the tested genotypes. the ils was nov 25 (d1) three ils of were dec 10 (d2), dec 25 and jan 10 (d4), respectively. sowing times were accommodated in main-plot and the test genotypes were assigned to sub-plot. the unit plot size was 4 m x 5 m. temperature (0c) imposed (10-day's average of minimum, maximum and its mean) during sowing to physiological maturity of wheat genotypes sowing in different times (d) at is presented in appendix-1 and average temperature imposed on growth stages of wheat genotypes (v) by sowing times (d) is presented in appendix 2. after well preparation of land, seeds @ 120 kg ha-1 of each variety / lines were sown continuously in lines 20 cm apart. each of the plots was fertilized @ 120-27-50-20-1-5000 kg ha-1 n-p-k-s-b-cd. cowdung was applied during land preparation. the source of n, p, k, s and b were urea, tsp, mop, gypsum and boric acid, respectively. all of tsp, mop, gypsum and boric acid; and two-third of urea were used as basal during final land preparation. rest urea was applied as top-dress at cri stage followed by irrigation. three irrigations were provided (one at cri stage, one early booting stage and one at initiation in grain filling). the plot was kept weed free up to 30 days. no plant protection measures taken to control insects and diseases. each of genotypes was harvested after its maturity. data on days to booting, heading, anthesis, physiological maturity, yield and yield contributing characters were recorded and the grain yield was adjusted at 12% moisture level. recorded data were analyzed statistically and the means were tested by the lsd at 5% level. 15 effect of terminal high temperature imposed by late sowing on phenological traits of wheat results and discussion the results of studied characters have been presented in the tables 1 to 9. findings of each character are discussed below: booting stage in irrigated timely sowings (its) all the genotypes phased their booting stage between 63-68 days. after timely sowing i.e. in late, the days of all genotypes decreased gradually. in late sowing conditions increased temperature (appendix 2) resulted in less time to attain booting stage. similar result was also observed by nahar, k. et al. (2010). among the variety, bari gom 28 looks significantly less time. in late sowing conditions, took average 5.0 -13.3% fewer days than timely sowing. bari gom 28, bari gom 27 and baw 1051 required 4.8-11.1%, 3.0-7.6% and 4.6-9.2% less days respectively than timely sowing. that is, the new varieties needed fewer days to attain booting stage as compared to bari gom 26. it indicated that, the bari gom 28 and bari gom 27 possess more heat tolerance. table 1. effect of terminal high temperature on days to booting of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 64 63 (1.56) 62 (3.12) 55 (14.1) 61 66 64 (1.72) 60 (4.23) 52 (13.8) 60 v2 63 62 (1.58) 60 (4.76) 54 (14.2) 59.7 64 62 (1.77) 59 (5.22) 51 (15.2) 59 v3 67 65 (2.98) 63 (5.97) 57 (14.9) 63 68 65 (3.21) 61 (6.14) 55 (16.7) 62.3 v4 64 63 (1.56) 60 (6.25) 56 (12.5) 60.7 65 62 (1.68) 58 (5.98) 51 (13.8) 59 mean-d 64.5 63.2 (2.01) 61.2 (5.11) 55.5 (13.9) 65.7 63.2 (2.09) 59.5 (5.39) 52.2 (14.8) year ls lsd(0.05) cv (%) d v dxvl dxvc d v dxvl dxvc d v dxvl dxvc 2012-13 ** ** ** ** 4.14 2.52 2.47 2.47 2.30 2.30 2.30 2.30 2013-14 ** ** ** ** 1.17 1.06 2.12 2.12 2.10 2.24 .2.24 2.24 figure in the parenthesis indicates decrease day in % over its heading stage like booting stage, high temperature imposed by sowing times influenced on heading of all the genotypes at both the years. in its all the genotypes phased their heading stage between 6772 days (table 2). after its, days to heading of all genotypes were decreased gradually. this is might be due to higher temperature prevailed in ils (table 2). nahar, k. et al. (2010) also observed the similar result. among the genotypes, bari gom 28 took significantly less time in all sowing times. new wheat varieties, bari gom 28, bari gom 27, bari gom 26 and baw 1051 required 1.9-10.8%, 2.4-9.3% and 0.0-8.7% less days respectively than timely sowing. these results implied that the performance in respect of heat tolerance of advanced genotypes were as in order of bari gom 28 > bari gom 27 > baw 1051>bari gom 26 16 hossain et al. table 2. effect of terminal high temperature on days to heading of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 71 70 (1.40) 65 (8.45) 60 (15.4) 66.5 72 69 (1.68) 64 (7.84) 58 (14.8) 65.7 v2 71 70 (1.40) 64 (9.85) 58 (18.30) 65.7 70 68 (1.65) 63 (8.52) 57 (16.2) 64.5 v3 74 72 (2.77) 66 (10.81) 62 (16.2) 68.5 75 73 (3.10) 65 (9.97) 60 (14.8) 68.2 v4 71 69 (2.81) 64 (9.85) 59 (16.9) 65.7 70 68 (2.97) 63 (8.87) 57 (15.2) 64.5 mean-d 71.7 70.2 64.5 59.7 71.3 69.5 63.7 58 year lsd(0.05) cv (%) d v d x vl vxvc d v dxvl dxvc 2012-13 5.13 2.12 2.09 1.77 1.77 1.77 1.77 1.77 2013-14 1.74 1.37 2.75 2.75 2.65 2.48 2.48 2.48 figure in the parenthesis indicates decrease day in % over its anthesis under high temperature conditions, earlier heading is advantageous in the retention of more green leaves at anthesis, leading to a smaller reduction in yield. growth chamber and greenhouse studies suggest that high temperature is most deleterious when flowers are first visible and sensitivity continues for 10-15 days. among the reproductive phases fertilization (13 days after anthesis) is one of the most sensitive stages to high temperature in various plants. in the present experiment, terminal high temperature imposed by sowing times had significant influence on days to anthesis of tested wheat genotypes. there was also significant variation among the genotypes to attain anthesis. of the tested genotypes bari gom 28 took less time (74 days) to reach the anthesis stage as compared to other genotypes in irrigated timely sowing (its). after its, days required to anthesis of all the genotypes decreased gradually. in irrigated late sowing (ils) conditions, bari gom 28 required the shortest duration and other two advanced genotypes needed longer duration in each location to reach the anthesis stage. in the high temperature stress condition, the days to anthesis reduced by 6.7-14.7% in bari gom 28, 1.3-10.7 % in bari gom 27 and 2.7-9.5% in baw 1051. ubaidullah et al. (2006) reported the same findings and observed that generally late sowing imposed negative effects on all the traits except bari gom 28. these results implied that in case anthesis the performance in respect of heat tolerance of tested genotypes were as in order of bari gom 28> bari gom 27 > baw 1051>bari gom 26 17 effect of terminal high temperature imposed by late sowing on phenological traits of wheat table 3. effect of terminal high temperature on days to anthesis of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 79 78 (1.26) 75 (5.06) 72 (8.86) 76 77 76 (1.67) 74 (6.63) 70 (10.8) 74.2 v2 75 74 (1.33) 67 (10.67) 64 (14.67) 70 76 75 (1.59) 68 (11.4) 63 (15.2) 70.5 v3 78 77 (1.28) 67 (14.10) 64 (17.9) 71.5 79 77 (1.32) 67 (14.2) 64 (18.5) 71.7 v4 74 75 (1.31) 66 (13.10) 64 (15.78) 70.2 74 75 (1.62) 66 (13.8) 63 (16.2) 69.5 meand 77.7 75.2 (3.21) 68.7 (11.58) 63.5 (18.27) 77.2 75.7 (1.55) 69 (11.5) 65 (15.1) year lsd(0.05) cv (%) d v d xvl d xvc d v d x vl dxvc 2012-13 5.13 2.12 2.09 2.09 1.77 1.77 1.77 1.77 2013-14 1.74 1.37 2.75 2.75 2.65 2.48 2.48 2.48 figure in the parenthesis indicates decrease day in % over its physiological maturity it is generally known that the duration of maturity of any crop is reduced by stress condition. high temperature in the post anthesis period shortens the duration of grain-filling (wiegand and cuellar, 1981). in our study, terminal high temperature imposed by sowing times had also considerable influence on days to physiological maturity of tested wheat genotypes. there was also significant variation among the genotypes to attain maturity. in irrigated timely sowing conditions (its), bari gom 27 took significantly the highest time for physiological maturation (108 days) and which was followed by & baw 1051 (106 days) while it was the lowest in bari gom 28. bari gom 28 also took the lowest days (106 days) among other two advanced genotypes (105 days) for maturation (table 4). after its, days required to maturity of all the genotypes decreased gradually. in irrigated late sowing (ils) conditions, bari gom 28 required the shortest duration and other two advanced genotypes needed longer duration to attain physiological maturity. in this experiment, in respect of sowing times and genotypes the temperature during the physiological maturing period was 24.4-25.8°c in case of its, and it was 23.3-29.2°c in ils conditions. in late sowings, temperatures prevailed higher during physiological maturity stage of wheat than its. in this condition, the days to maturity reduced by 0.9-12.6% in bari gom 28, 1.0-9.5 % in bari gom 27 and 1.9-12.4% in baw 1051. that is why, due to higher temperature all the tested genotypes matured earlier in ils condition as compared to its. there is a similarity between the result of the present study and that of ubaidullah et al. (2006) and nahar et al. (2010). these results implied that in case maturity the performance in respect of heat tolerance of tested genotypes were as in order of bari gom 28> baw 1051 > bari gom 26> bari gom 27. 18 hossain et al. table 4. effect of terminal high temperature on days to physiological maturity of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 107 104 (2.80) 95 (11.2) 83 (22.4) 97.2 106 104 (2.78) 94 (12.1) 82 (21.8) 96.5 v2 106 103 (2.83) 94 (11.32) 83 (21.69) 96.5 105 103 (2.97) 93 (11.9) 81 (22.3) 95.5 v3 108 104 (3.70) 96 (11.1) 85 (21.2) 98.2 109 105 (3.52) 95 (10.8) 84 (19.8) 98.2 v4 106 103 (2.83) 95 (10.3) 84 (20.7) 97 107 104 (2.4) 94 (11.3) 82 (21.3) 96.7 mean -d 106. 7 103.5 (2.99) 95 (10.96) 83.7 (21.5) 106. 7 104 (2.91) 94 (11.5) 82.2 (21.3) year lsd(0.05) cv (%) d v dxvl dxvc d v dxvl dxvc 2012-13 5.43 3.12 2.12 2.12 1.21 1.21 1.21 1.21 2013-14 1.24 0.72 1.24 1.24 3.03 1.07 1.07 1.07 plant height effect of terminal high temperature imposed by sowing times on plant height at maturity was statistically significantamong the tested genotypes and also interaction effect between sowing times and genotypes (table 5). baw 1120 and baw 1051 produced numerically the taller plants (99 cm) while bari gom 28 produced the shortest plant (93.7 cm) in its condition. in ils conditions, maximum plant height (94.5 cm) was recorded from bari gom 27 followed by bari gom 28 (94.3 cm) and baw 1051 (91.8 cm) sowing on dec 10. in case of dec 25 sowing, baw 1051 and bari gom 27 produced the plant of same height (93.5 cm) and bari gom 28 gave the shortest plant (92.5 cm). in the late sowing on jan 10, baw 1051 gave the maximum plant (94.8 cm) followed by bari gom 27 (93 cm) while bari gom 28 resulted shortest plant height (92.7 cm). these results implied that performance of advanced genotypes in respect of taller plant height was in order of bari gom 26 ≥ bari gom 27> bari gom 28>baw 1051. table 5. effect of terminal high temperature on plant height (cm) of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 109.8 102.7 96.2 82.2 97.7 110.1 106.4 95.8 83.2 98.8 v2 103.7 97.8 96.4 81.4 94.8 105.4 102.3 95.4 82.3 96.3 v3 103.1 102.2 97.2 79.2 95.5 105.2 103.4 96.7 80.5 96.1 v4 103.1 100.4 98.5 81.1 95.8 104.8 102.3 99.7 81.7 97.1 meand 104.9 100.7 97.1 80.9 106.3 103.6 96.9 81.9 year lsd(0.05) cv (%) d v dxvl dxvc d v dxvl dxvc 2012-13 7.79 1.79 4.60 4.60 2.82 2.82 2.82 2.82 2013-14 3.03 2.62 2.49 2.49 1.77 1.54 1.54 1.54 figure in the parenthesis indicates decrease day in % over its 19 effect of terminal high temperature imposed by late sowing on phenological traits of wheat spike density spike density is one the important yield contributing factor for wheat. it may be varied due to different stress situation. in this study, both the main effect of terminal high temperature forced by sowing times and genotypes was significant on spike density in each location. interaction effect between sowing time and genotypes was significant. spike density decreased with the delay in sowings (table 6). the genotype bari gom 28 produced second highest number (380) of spike m-2 and the value was statistically identical to the value (351) noted from baw 1051. in the latest sowing of jan 10, the advanced genotypes produced higher spikes per unit area than the released variety, bari gom 26. that is, among the advanced genotypes, bari gom 27 and bari gom 28 performed better both in its and ils condition. on the other hand, the same two genotypes performed better in ils condition. table 6. effect of terminal high temperature on spike density (number m-2) of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 meanv its ils its ils v1 388 341 319 299 336.7 362 324 314 311 327.7 v2 372 349 319 306 336.5 342 329 322 317 327.5 v3 458 423 348 299 382 412 419 398 402 407.7 v4 456 348 315 306 356.2 398 351 319 302 342.5 mean-d 418.5 365.2 325.2 302.5 389.7 355.7 338.2 333 year lsd(0.05) cv (%) d v d x vl d x vc d v dxvl dxvc 2012-13 21.45 21.45 11.42 11.42 7.04 9.96 11.65 11.65 2013-14 27.10 15.40 51.25 50.71 8.69 8.69 8.39 8.39 figure in the parenthesis indicates decrease day in % over its grains spike-1 number of grains spike-1 is also one of the major criteria to influence grain yield of wheat. heat stress, singly or in combination with drought, it is common constraint during anthesis and grain filling stages in many cereal crops of temperate region (nahar et al., 2010). in this study, terminal high temperature imposed by late sowings had significant effect on number of grains spike-1 (table 7). on the other hand, interaction effect between sowing times and genotypes was significant. the significant interaction effect between sowing times and genotypes indicated that tested genotypes performed differently in different sowing times. here, baw 1051 produced numerically the maximum number of grains (48.3) spike-1 from the late sowing of dec 10. statistically identical numbers of grain spike-1 were also recorded from timely sowing of nov 30 and late sowings of dec 25 and january 10. this implied that, this genotype could be sown in timely sowing time and even very late i.e. up to jan 1 for getting higher number of grain spike-1. high temperature prevailed in reproductive stage due to late sowing could not affect grain formation indicating that this genotype could be identified as a good heat tolerant genotype, if data is authentic. next minimum numbers of grain (48.0) spike-1 was recorded from bari gom 28 in late sowing of dec 10 and it was identical to the number noted from the delayed sowing of jan 10. on the contrary, late sowing dec 25 and timely sowing nov 25 of the same genotype produced e significantly minimum numbers of grains. during reproductive stage, the mean temperature was higher (in late sowing conditions (20.9-29.0 0c for dec 10 sowing, 22.5-29.4 0c for dec 25 sowing and 24.0-28.0 0c for jan sowing) than timely 20 hossain et al. sowing (17.0 -25.7 0c). the data on temperature and result in respect of grain spike-1 might be inconsistent. table 7. effect of terminal high temperature on grains spike-1 of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 meanv its ils its ils v1 51.0 54.3 49.0 40.3 48.6 50 52.3 49.2 41.2 48.1 v2 49.0 57.3 42.0 40.0 47.1 50.3 55.3 43.2 39.2 47.0 v3 43.3 38.0 41.0 44.3 41.6 46.5 48.3 42.2 44.4 45.3 v4 45.6 48.3 41.6 44.6 45.0 46.5 49.2 43.8 41.2 45.1 mean-d 47.2 49.4 43.4 42.3 48.3 51.2 44.6 41.5 year lsd(0.05) cv (%) d v dxvl dxvc d v dxvl dxvc 2012-13 2.19 4.50 5.67 5.67 14.19 10.12 10.12 10.12 2013-14 1.46 1.95 3.90 3.90 3.96 6.27 6.27 6.27 figure in the parenthesis indicates decrease day in % over its thousand grain weight (tgw) like number of grains spike-1, tgw was also influenced by the terminal high temperature imposed sowing times (averaged over genotypes) and genotypes (averaged over sowing times. interaction effect between genotypes and sowing times was significant (table 8). tgw averaged over genotypes also decreased with delay in sowing. the maximum tgw of 48.4 g was recorded from irrigated timely sowing (nov 30) and it was statistically identical to the weight noted from late sowings of dec 15-30. last sowing (jan 15) resulted in the minimum tgw (23.3 g). here, bari gom 28 succeeded to generate significantly the maximum tgw. other genotypes performed similarly. this result implied that, all the tested genotypes were found to be better for normal and late sowings up to dec 30. all the genotypes also resulted in lower tgw in late sowings of dec 25 and jan 10. on the contrary, higher tgw was noted from nov 25 and dec 10 sowings. table 8. effect of terminal high temperature on tgw (g) of wheat genotypes (v) imposed by late sowing times (d) at rajshahi during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 44.6 36.6 32.0 29.3 35.6 45.3 44.8 33.8 30.4 38.5 v2 43.0 37.0 34.3 34.0 39.5 44.7 43.5 34.2 32.4 38.7 v3 35.0 30.6 23.3 23.3 28.1 38.5 37.9 29.5 24.3 32.5 v4 49.0 39.3 34.0 35.0 39.3 48.7 45.5 35.2 33.4 40.7 mean-d 45.2 42.2 32.8 30.4 44.3 42.9 33.1 30.0 year lsd(0.05) cv (%) d v d x vl d x vc d v dxvl dxvc 2012-13 5.45 3.04 8.81 8.81 10.18 14.19 14.19 14.19 2013-14 2.04 2.48 4.96 4.96 4.95 7.15 7.15 7.15 figure in the parenthesis indicates decrease day in % over its 21 effect of terminal high temperature imposed by late sowing on phenological traits of wheat grain yield interaction between of terminal high temperature imposed by sowing times and genotypes wheat had significant effect on grain yield (table 9). this meant that grain yield of each genotype was different in each sowing times. in irrigated timely sowing conditions (its), all the genotypes resulted in significantly higher grain yield and thereafter yield decreased with the delay of sowing times. that is, yield recorded from its was significantly higher than all sowings of ils conditions. under ils conditions, the advanced genotype baw 1141 generated significantly the highest grain yield (5.31 t ha-1). this yield was statistically identical to the yield noted from other advanced genotypes. just after 15days of its, (dec 10) there was no significant yield variation among the genotypes but after 15 days (dec 25) significant yield variation among the genotypes. in this sowing, yield reduction of the genotypes bari gom 26, baw 1051, bari gom 27 and bari gom 28 was 26.3%, 22.8%, 18.9% and 21.3%, respectively as compared to its condition. in late sowing of jan 10, bari gom 28 also produced significantly the highest yield (3.65 t ha-1). other two advanced genotypes performed identically resulting in a yield more than 2 t ha-1. at that time percent of yield reduction was remarkable and it was 39.8%, 29.7%, 26.4% and 25.6.2 % in bari gom 26, baw 1051, bari gom 27 and bari gom 28, respectively. considering the yield performance, the variety bari gom 28 performed better than other genotypes in all sowing times though there was significant yield reduction over timely sowing. this line produced more than 4.18 tha-1 grain yield up to dec 25 sowing and it also produced 3.65 tha1 grain yield in january 10 sowing. this indicates that among the tested genotypes, it is better in heat stress condition. in late sowing conditions (dec 25 –jan 10), the grain yield was reduced by12.8-38.8% in bari gom 26, 14.4-30.2% in baw 1051, 11.5-26.4% in bari gom 27 and 17.4-25.6% in bari gom 28. table 9. effect of terminal high temperature on grain yield (t ha-1) of wheat genotypes (v) imposed by late sowing times (d) during 2012-13 and 2013-14 v 2012-13 2013-14 d1 d2 d3 d4 mean v d1 d2 d3 d4 mean v its ils its ils v1 5.15 5.16 (0.97) 4.50 (12.6) 2.78 (46.0) 4.39 5.23 5.09 (2.67) 4.42 (13.1) 2.93 (33.7) 4.41 v2 4.75 4.66 (1.89) 3.56 (12.4) 2.61 (34.5) 4.24 4.57 4.42 (3.28) 3.69 (16.5) 2.77 (24.9) 3.86 v3 4.47 4.25 (4.92) 3.83 (14.3) 2.68 (40.0) 3.81 4.41 4.32 (2.04) 3.94 (8.79) 3.43 (12.9) 4.02 v4 5.36 5.08 (5.22) 4.25 (20.7) 3.75 (30.0) 4.61 5.27 5.04 (4.36) 4.11 (18.4) 3.57 (13.8) 4.47 meand 4.93 4.78 (3.24) 4.18 (15.21) 3.15 (36.10) 4.87 4.71 (3.08) 4.04 (14.1) 3.17 (21.3) year lsd(0.05) cv (%) d v d x vl d x vc d v d xvl dxvc 2012-13 0.78 3.03 0.77 0.77 9.34 10.18 10.18 10.18 2013-14 0.47 0.14 0.29 0.29 10.21 9.13 9.13 9.13 figure in the parenthesis indicates decrease day in % over its 22 hossain et al. table 10. yield of wheat genotypes (v) decrease in percentage over irrigated timely sowing condition (tis) for 10c rise in average mean temperature from booting to maturity at rajshahi during 2012-13 and 2013-14 genotypes 2012-13 2013-14 d1 d2 d3 d4 d1 d2 d3 d4 its ils its ils v1 1.1 7.3 14.2 1.3 8.2 16.7 v2 1.7 8.3 12.5 2.1 10.5 18.9 v3 3.9 9.3 12.7 4.1 9.5 12.2 v4 4.8 9.6 10.6 3.5 9.8 13.4 it was also observed that that grain yield was found to be reduced by about by 7.7-15.4% in bari gom 26, 9.4-15.7 % in baw 1051, 9.4-12.4% in bari gom 27 and 9.7-12.0% in bari gom 28 from irrigated timely sowing condition (its) for each 1°c rise in average mean air temperature during booting to maturity in both the season (table 10). on the other hand, reduction percent were less for the advanced lines and new varieties. grain yield reduction was about (-) 1.4-2.65% in bari gom 28, 0.1-6.7 % in bari gom 27 and 1.7-6.0% in baw 1051. conclusion from the above study, it can be concluded that terminal high temperature imposed by late sowing significantly changes the studied phenology of advanced genotypes and the yield. generally due to high temperature stress the stages of life cycle reduce their duration or length. the performance of all genotypes is better in all respect in irrigated timely sowings as compared to irrigated late sowings conditions. the advanced variety bari gom 28 is the best performing one in heat stress condition as the deviation of phenological stages reduced by the lowest percentage and the yield is the highest among all the varieties. bari gom 27 could take place after bari gom 28 followed by baw 1051. references chio, b. h., k. y. park and r. k. park. 1992. a study of cultural methods for summer buckwheat sown in spring. korean j. crop sci. 37:149-154. fischer, r. a. 1985. physiological limitations to producing wheat in semi-tropical and tropical environments and possible criteria. in: r. c. villareal and a. r. klatt (eds.), wheats for more tropical environments p.209-230. cimmyt, maxico, d. f. liszewski, m. 1999. response of buckwheat to early planting depending on weather conditions. folia-universitatis agriculturae stetinensis. agricultura 79:139-141. michiyama, h., a. fukui and h. hayashi. 1998. differences in the progression of successive flowering between summer and autumn ecotype cultivars in common buckwheat (fagopyrum esculentum moench). japan j. crop sci. 64:498-504. nahar, k., k. u. ahamed and m. fujita. 2010. phenological variation and its relations with yield in several wheat (triticunm aestivum l.) cultivars under normal and late sowing mediated heat stress condition. not. sci. biol. 2(3):51-56. pecio, a. and b. wielgo. 1999. buckwheat yielding and structure of plant and canopy dependent of sowing time. frag. agron. 16:5-17. 23 effect of terminal high temperature imposed by late sowing on phenological traits of wheat wahid, a., s. gelani, m. ashraf and m. r. foolad. 2007. heat tolerance in plants: an overview. environ. exp. bot. 61:199-223. wanjura, d. f. and d. r. buxtor. 1972. hypocotyle and radicle elongation of cotton as affected by soil environment. agron. j. 64:431-435. wiegand, c. l. and j. a. cuellar. 1981. duration of grain filling and kernel weight of wheat as affected by temperature. crop sci. 21:95-101. ubaidullah, t., m. raziuddin, s. hafeezullah, a. ali and w. nassimi. 2006. screening of wheat (triticum aestivium l.) genotypes for some important traits against natural terminal heat stress. pak. j. biol. sci. 9:2069-2075. 24 hossain et al. appendix 1.temperature (0c) imposed (10-day's average of minimum, maximum and its mean) during sowing to physiological maturity of wheat genotypes sowing in different times (d) in 2012-13 and 2013-14 2012-2013 10-days (#) minimum maximum mean d1 d2 d3 d4 d1 d2 d3 d4 d1 d2 d3 d4 1 14.8 11.9 12.5 10.7 28.5 21.9 25.2 22.6 21.7 16.9 18.8 16.7 2 15.6 9.2 13.4 9.9 24.7 20.5 23.2 23.7 20.2 14.8 18.3 16.8 3 9.2 12.9 10.0 10.2 20.3 25.3 22.7 26.7 14.7 19.0 16.4 18.5 4 12.5 12.8 9.1 12.8 25.2 22.9 24.9 27.2 18.8 17.8 17.0 19.9 5 13.4 10.0 10.8 12.9 23.2 22.8 26.6 30. 18.3 16.5 18.7 21.7 6 10.1 9.2 13.4 15.3 22.7 25.1 28.8 32.9 16.4 17.2 21.1 24.1 7 9.1 10.9 13.6 16.3 24.9 26.7 31.6 31.8 17.0 18.8 22.6 24.1 8 10.8 13.9 16.5 19.1 26.6 29.4 32.8 35.5 18.7 13.9 24.7 27.3 9 13.4 13.4 18.4 21.1 28.8 31.6 33.0 34.7 21.1 22.5 25.7 27.8 10 13.6 16.9 20.7 31.6 32.6 37.2 22.6 24.7 28.8 11 16.7 21.3 33.7 35.4 25.3 25.9 2013-2014 10-days (#) minimum maximum mean d1 d2 d3 d4 d1 d2 d3 d4 d1 d2 d3 d4 01 11.6 13.9 9.6 9.0 27.2 24.1 22.3 24.1 19.4 19.0 16.0 18.5 02 25.2 10.8 8.1 9.0 25.2 18.3 20.2 23.3 19.1 14.5 14.1 16.1 03 12.2 9.8 10.9 12.6 20.6 22.5 25.4 27.2 16.4 16.1 18.1 19.9 04 9.6 8.18 8.8 12.9 22.3 23.1 23.9 26.5 16.0 15.6 16.4 19.7 05 8.1 9.4 12.7 14.3 20.2 23.4 27.8 29.6 14.1 16.4 20.2 21.3 06 10.9 11.8 13.9 15.3 25.4 27.4 26.5 31.9 18.1 19.6 20.2 23.6 07 8.8 13.1 17.6 19.0 23.1 26.3 33.8 34.2 16.4 19.7 25.7 26.6 08 12.7 14.4 14.5 20.0 27.8 28.8 30.7 35.3 20.2 21.0 22.0 27.7 09 13.9 16.7 19.1 20.5 26.5 31.8 34.3 37.9 20.2 23.4 26.7 29.2 10 17.6 18.9 20.5 23.5 33.8 34.1 36.1 36.7 25.7 26.5 28.3 30.1 11 14.5 19.6 21.9 22.9 30.7 35.2 39.0 34.3 22.0 27.4 30.5 28.6 12 19.1 20.6 22.2 22.8 34.3 37.5 33.4 34.5 26.7 29.0 27.8 28.6 13 20.0 23.3 36.7 37.1 28.3 30.2 14 21.9 22.7 39.0 34.1 30.5 28.4 15 22.2 33.4 27. appendix 2. average temperature imposed on growth stages of wheat genotypes (v) by sowing times (d) in 2012-13 and 2013-14 booting 2012-13 v sowing time its irrigated late sowing (ils) d1 d2 d3 d4 min max mean min max mean min max mean min max mean v1 9.5 24.3 16.9 8.4 24.3 16.4 16.0 33.0 24.5 16.2 32.6 24.4 v2 9.1 25.0 17.1 8.0 25.5 16.8 14.6 32.0 23.3 15.8 32.5 24.2 v3 9.5 25.4 17.5 13.4 29.0 21.2 13.4 30.7 22.1 17.3 34.0 25.7 v4 9.4 24.7 17.0 8.5 26.2 17.3 14.2 32.4 23.3 16.4 32.5 24.4 25 effect of terminal high temperature imposed by late sowing on phenological traits of wheat v sowing time its irrigated late sowing (ils) d1 d2 d3 d4 min max mean min max mean min max mean min max mean booting 2013-14 v1 10.69 23.43 17.06 10.8 23.38 17.08 10.9 24.69 17.81 11.72 26.36 18.9 v2 10.30 23.30 17.05 10.96 23.69 17.33 10.78 24.50 17.64 11.8 26.46 19.11 v3 10.61 23.48 17.05 10.9 23.52 17.12 11.17 25.17 18.08 12.01 26.80 19.40 v4 10.69 23.43 17.06 10.8 23.38 17.08 10.9 24.69 17.81 11.8 26.69 19.30 heading 2012-13 v1 9.6 26.5 18.1 18.4 29.4 23.9 14.5 31.5 23.0 17.7 29.0 23.4 v2 8.5 25.4 17.0 12.4 29.3 20.9 13.2 31.2 22.2 15.0 30.6 22.8 v3 11.0 24.5 17.7 16.5 30.2 23.4 11.4 29.2 20.3 18.2 32.2 25.2 v4 10.6 24.7 17.6 15.5 29.8 22.6 12.3 30.5 21.4 16.7 31.4 24.1 heading 2013-14 v1 10.68 23.64 17.16 11.09 23.67 17.38 11.11 24.99 18.05 12.22 27.13 19.68 v2 10.68 23.64 17.16 11.09 23.67 17.38 11.24 25.27 18.16 12.07 26.90 19.38 v3 10.76 23.87 17.31 11.11 23.75 17.43 11.17 25.15 18.15 12.43 27.38 19.81 v4 10.68 23.64 17.16 17.73 24.00 17.59 11.24 25.27 18.16 12.13 26.99 19.46 anthesis 2012-13 v1 10.2 28.0 19.1 10.7 28.4 19.6 13.7 32.6 23.2 15.0 32.8 23.9 v2 12.5 28.0 20.2 13.4 30.7 22.1 15.6 34.4 25.0 20.3 31.5 25.9 v3 8.5 25.4 17.0 12.4 29.3 20.9 13.0 32.0 22.5 17.5 30.5 24.0 v4 8.2 24.9 16.5 12.9 30.4 21.6 13.7 32.4 23.0 17.9 31.2 24.5 anthesis 2013-14 v1 10.89 24.06 17.48 11.35 24.14 17.67 11.67 25.92 18.72 13.3 28.2 20.7 v2 10.82 23.95 17.39 11.18 23.75 17.46 11.23 25.20 18.13 12.6 27.5 19.9 v3 10.9 24.01 17.46 11.28 24.06 17.59 11.23 25.20 18.13 12.6 27.5 19.9 v4 10.85 23.98 17.42 11.2 23.86 17.53 11.19 25.13 18.08 12.6 27.5 19.9 maturity 2012-13 v1 18.6 33.0 25.8 22.4 36.0 29.2 21.4 35.3 28.4 23.3 35.0 29.2 v2 16.2 32.6 24.4 13.7 32.8 23.3 22.6 38.4 30.5 21.5 36.4 29.0 v3 17.3 34.0 25.7 21.4 36.6 29.0 20.5 38.3 29.4 19.5 35.6 27.6 v4 17.2 34.2 25.3 21.1 33.2 27.1 21.2 37.5 29.3 19.3 34.2 26.7 maturity 2013-14 v1 11.89 25.57 18.68 13.02 26.37 19.81 13.46 28.06 20.70 14.5 29.5 22.0 v2 11.84 25.48 18.61 12.74 26.30 19.46 13.36 27.97 20.61 14.5 29.5 22.0 v3 12.05 25.66 18.75 13.02 26.37 19.81 13.53 28.17 20.82 14.5 29.6 22.1 v4 11.84 25.48 18.61 13.02 26.37 19.81 13.46 28.06 20.70 14.5 29.5 22.0 its: irrigated timely sowing, d1: nov 25, d2: dec 10, d3: dec 25 and d4: jan 10 response of wheat (triticum aestivum) to sowing time and nitrogen in high barind tract bangladesh agron. j. 2014, 17(1): 103-106 short communication effet of plant spacing and depth of usg placement on yield of boro rice s. das1, a. k. chaki2, n. sobhan1, m. m. hossain3 and h. m. arshad4 1scientific officer, soil science division, bangladesh institute of nuclear agriculture, mymensingh 2scientific officer, on-farm research division, bangladesh agricultural research institute, gazipur 3assistant manager, category and procurement, aci limited, dhaka 4assistant director, farm division, badc, dattanagar, jhenaidah corresponding author: dasshilpi84@yahoo.com the farmers have to produce maximum rice from minimum land by adopting improved agronomic practices. spacing of transplanting and depth of placement of urea super granules (usg) can play a significant role in increasing yield of rice. the plant to plant and row to row distances determine the plant population per unit area. plant spacing has a direct effect on the yield of rice. the tillering habit and production of spikelets and panicles plant-1 depends on the spacing of transplanting which is responsible for variation in yield of rice. the plant spacing influences the availability of sunlight, leaf area index (lai), nutrient to the plant and also photosynthesis and respiration. nitrogen is an essential element which influences the vegetative growth, seed development, yield and quality of rice. the loss of nitrogen is a problem for rice cultivation in this country. modified urea fertilizers like usg, sylph coated urea etc. are designed to control one or more types of nitrogen loss to which ordinary urea is commonly susceptible. the superiority of usg, a slow releasing nitrogenous fertilizer, over conventional form of urea providing a steady supply of available nitrogen throughout the growing period of the crop. it may be important to know the optimum depth of placement of urea supper granules on the growth, development and yield of boro rice. an increase in the yield of boro rice can be expected if appropriate combination of spacing and depth of placement of urea supper granules is used. the present study was, therefore, undertaken with the objectives to study the response of spacing of transplanting and depth of placement of urea super granules (usg) on the yield of boro rice. the experiment was conducted at the agronomy research field, bangladesh agricultural university (bau), mymensingh in the boro season during 2008-2009. it belongs to the non-calcareous dark grey flood plain soil under the agro-ecological region of the old brahmaputra floodplain. the experimental field was medium high with moderate drained condition. the land was silty loam in texture having a soil ph 6.42, and moderate in organic matter content. the experiment was laid out in a two factor randomized complete block design (rcbd) with three replications. the experiment comprised of two spacing of transplanting viz; 20 cm x 20 cm and 20 cm x 25 cm and three depths of placement of urea super granules viz; 6cm, 8cm and 10cm. the sprouted seeds of brri dhan29 were sown in the nursery bed on 02 december 2008. phosphorus @ 120 kg ha-1 as triple super phosphate, potassium @ 60 kg ha-1 as muriate of potash, sulphur @ 40 kg ha-1 as gypsum and zinc @ 10 kg ha-1 as zinc sulphate were applied as a blanket dose in all the plots. a 2.7 g urea supper granule was applied at depths of 6 cm, 8 cm and 10 cm at the centre of four hills of two adjacent rows at 10 days after transplanting (dat). thirty five days old seedlings were transplanted on the well puddled experimental plots on 06 january 2009. the collected data were compiled and tabulated for statistical analysis and means were adjudged by duncans multiple range test (gomez and gomez, 1984). number of effective tillers hill-1, number of grains panicle-1, grain yield and straw yield of boro rice was significantly influenced by spacing of transplanting (table 1). the higher number of effective tillers hill-1 (13.37) was obtained from 20 cm x 25 cm spacing than (12.87) 20 cm x 20 cm. the result revealed that 20 cm x 25 cm spacing of transplanting had the greatest opportunity to produce more number of effective tillers hill-1. it might be due to the fact that wider spacing of transplanting provided enough nutrients, light and air which played vital role in producing more effective tillers hill-1 . the results are in agreement with the findings of haque (2002). the higher number of grains panicle-1 (115.84) was obtained from 20 cm x 104 das et al. 25 cm spacing of transplanting than from 20 cm x 20 cm spacing of transplanting (114.74). this result was in agreement with that of sarker et al. (2002). depth of placement of urea super granules showed a significant response on all the yield and yield contributing characters except panicle length and weight of thousand grains (table 2). the highest number of effective tillers hill-1 (16.39) was obtained from 8 cm depth of placement of usg and the lowest number (11.39)from 10 cm which followed by 6 cm. the highest number of grains panicle-1 (126.77) was found in 8 cm depth of placement of usg and the lowest (107.94) in 6 cm. continuous availability of nitrogen at 8 cm depth of placement of usg might enhance grain formation and development which eventually resulted in increased number of grains panicle-1. the highest grain yield (5.08 t ha-1) was found in 8 cm depth of placement of usg and the lowest one (3.73 t ha-1 in 6 cm depth. eight centimeter depth of placement of usg produced the highest number of effective tillers hill-1 and number of grains panicle-1 and ultimately gave the highest grain yield. the highest straw yield (6.18 t ha-1) was obtained from 8 cm depth of placement of usg and the lowest (5.33 t ha-1) from 6 cm depth. similar trend was followed in harvest index. table 1. response of plant spacing on different crop characters, yield components and yield of boro rice spacing of transplanting plant height (cm) no. of effective tillers hill-1 panicle length (cm) no. of grains panicle-1 weight of 1000 grains (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) s1 96.45 12.87 21.92 114.74 21.75 4.46 5.70 43.63 s2 98.06 13.37 21.67 115.84 21.21 4.24 5.58 43.01 s(χ ) 0.42 0.18 0.20 0.61 0.12 0.04 0.04 0.28 cv(%) 4.41 7.23 4.14 3.57 10.01 5.77 7.47 4.53 table 2. response of depth of placement of urea super granules on different crop characters, yield components and yield of boro rice depth of usg 4 hills-1 plant height (cm) no. of effective tillers hill-1 panicle length (cm) no. of grains panicle-1 weight of 1000 grains (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) d1 94.56c 11.49b 21.43 107.94c 21.54 3.73c 5.33b 41.01 d2 101.04a 16.39a 21.98 126.77a 21.25 5.08a 6.18a 45.13 d3 96.17b 11.39b 21.98 111.15b 21.66 4.23b 5.41b 43.82 s(χ ) 0.52 0.22 0.25 0.75 0.14 0.04 0.05 0.34 cv (%) 4.41 7.23 4.14 1.68 10.01 3.57 7.47 4.53 the effect of interaction of spacing of transplanting and depth of placement of urea super granules showed significant variation in respect of plant height, number of effective tillers hill-1, number of grains panicle-1 and grain yield except panicle length, weight of thousand grains and straw yield (table 3). the highest number of effective tillers hill-1 (16.80) was obtained from 20 cm x 25 cm spacing of transplanting x 8 cm depth of placement of usg and the lowest one (10.39) from 20 cm x 25 cm spacing of transplanting of 6 cm depth. similar trend was followed in case of no. of grains panicle-1. from table 3, it is evident that the highest grain yield (5.30 t ha-1) was obtained from 20 cm x 20 cm spacing of transplanting x 8 cm depth of placement of usg, while the lowest one (3.68 t ha-1) from 20 cm x 20 cm. it is evident that the highest straw yield (5.82) was found in the interaction of 20 cm x 25 cm spacing of transplanting and 2.7 g usg (68 kg n ha-1) and the lowest (5.16 t ha-1) 20 cm x 25 cm spacing of transplanting x 1.8 g usg (46 kg n ha-1). 105 spacing and usg placement on yield of boro rice table 3. response of interaction of spacing of transplanting and depth of urea super granules placement on different crop characters, yield components and yield of boro rice interaction (s x d) plant height (cm) no. of effective tillers hill-1 panicle length (cm) no. of grains panicle-1 weight of 1000 grains (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) s1×d1 92.30c 12.59b 21.23 105.82c 21.61 3.68e 5.32 40.67 s1×d2 100.45a 15.97a 22.10 127.04a 21.59 5.30a 6.32 45.60 s1×d3 96.59b 10.05c 22.43 111.36b 22.06 4.40c 5.45 44.63 s2×d1 96.82b 10.39c 21.63 110.07b 21.47 3.79e 5.34 41.36 s2×d2 101.63a 16.80a 21.86 126.50a 20.91 4.86b 6.04 44.67 s2×d3 95.74b 12.92b 21.53 110.95b 21.25 4.06d 5.36 43.01 sχ 0.73 0.32 0.35 1.06 0.20 0.06 0.07 0.48 cv (%) 4.41 5.14 4.14 3.57 10.01 5.77 7.47 4.53 s1= 20 cm x 20 cm, s2= 20 cm x 25 cm d1= 6 cm, d2= 8 cm, d3= 10 cm in a column, figures with same letters or without letters do not differ significantly whereas figures with dissimilar letter differ significantly as per dmrt. based on the results of the study it can be concluded that the spacing of transplanting of 20 cm x 20 cm in combination with 8 cm depth of placement of usg is the best for obtaining higher yield of boro rice under the agro-ecological conditions of present study. references gomez, k. a. and a. a. gomez. 1984. duncan's multiple range test. statistical procedures for agricultural research. 2nd edn., a wiley inter-science publication, john wiley and sons, new york. pp.202-215. haque, d. e. 2002. effect of madagascar technique of younger seedling and wider spacing on the growth and yield of boro rice. m.s. thesis, dept. agron., bangladesh agril. univ., mymensingh. pp.28-71. sarker, g., m. rahman, r. hasan and s. c. roy. 2002. system of rice intensification: yield and economic potential in boro rice at different location of bangladesh. life-nopest-ii project, care, bangladesh. pp.1-5. performance of soybean varieties in hilly areas bangladesh agron. j. 2014, 17(1): 107-108 short communication performance of soybean varieties in hilly areas m. shaheenuzzamn, a. biswas, m. m. karim and m. k. islam agronomy division, bangladesh agricultural research institute, joydebpur, gazipur corresponding author: shaheenuzzamn@gmail.com key words: hill agriculture, protein and vegetable oil, soybean soybean (glycine max l. merr.) is a leguminous crop and a good source of protein and vegetable oil. it can play a vital role in balancing the protein deficiency of our diet (mondal and wahhab, 2001; rahman, 2003). at present, the domestic oilseed production of bangladesh is 0.63 million tons, which gives only 0.20 million tons of edible oil and can meet 25-30% requirement (hossain and rahman, 2008). to fulfill the requirement, bangladesh is to import 1.20 million tons of edible oil annually at a cost of nearly tk. 40 billions. there is a possibility of producing 1.6-1.8 million tons of soybeans from 0.7 million hectares of char land and from other seasonal fellow land in bangladesh as well hill region in chittagong hill tract. so, the present experiment has been undertaken to evaluate the performance of soybean varieties in respect of maturity period, seed yield and yield contributing characters at three different locations of cht zone for the development of soil condition as well as increase productivity of oil crops. the experiment was conducted at hill valley of hill agricultural research station, ramgarh, khagrachari during kharif-2 season of 2011-12 and 2012-13. the soil of this hill area belongs to aez 27 and the soil bears acidic soil. three different soybean varieties (shohag, bari soybean-5 and bari soybean-6) were included in the experiment. the trial was laid out in a randomized complete block design with five replications. the unit plot size was 3 m x 3 m. seeds of soybean (shohag, bari soybean-5 and bari soybean-6) were sowing according to treatment with the spacing of 30 cm x 30 cm. lime was applied due to minimize the acidity effect. fertilizers at the rate of 60-175-120-115 kg ha-1 as urea, triple super phosphate (tsp) muriate of potash (mop) and gypsum respectively along with 10 ton cowdung. all fertilizers were applied as basal during final land preparation. weeding, irrigation and insecticides were sprayed as and when required to maintain an optimum growth condition for the crop. it was harvested after 95 days after sowing when the pods were turned to yellowish color and leaves were fallen down. plant height, number of branches plant-1, number of pods plant-1, number of seeds plant-1, weight of seeds plant-1, 1000-seed weight and yield (t ha-1) were recorded. the collected data were analyzed statistically and means were separated using lsd test at 5% level of significance. the result showed that there were significant differences observed among the tested soybean varieties, i.e., plant height (cm), no. of branch plant-1, no. of pod plant-1, no. of seed pod-1, weight of seeds plant-1 (g), 1000-seed wt. (g) and yield (tha-1). the soybean var. bari soyabean-6 was recorded the highest plant height 60.00 and 61.50 cm among the varieties and the lowest 57.35 and 55.76 cm by shohag in 2011-12 and 2-12-13, respectively. the highest number of pods plant-1 (14.00 and 13.66) was found in bari soybean-6 in both the years. the highest numbers of seeds pod-1 (2.68 and 2.48) were recorded from the variety shohag while bari soyabean-5 recorded the lowest number of seeds pod-1 (2.47) during 2011-12 and bari soyabean-6 (2.16) during 2012-13. the highest weight of seeds plant-1 (8.77 g and 7.92 g) was recorded in shohag in both years and the lowest weight of seeds plant-1 (6.45 g and 5.58 g) were from bari soybean-6. the highest 1000-seed weight (90.00 g and 89.00 g) were recorded from bari soybean-5 and the lowest 1000-seed weight from bari soyabean-6. the highest seed yield of 0.58 and 0.55 t ha-1 was recorded from bari soybean-6 that followed by shohag (0.52 and 0.50 t ha-1) and the lowest yield (0.48 t ha-1 and 0.46 t ha-1) from bari soybean-5 for both the cropping years. although average yield of bari released varieties is 1.5-2 t ha-1 but in the hilly region, all the varieties were produced lower yield. it might be due to prevailing lower temperature during growing season. 108 shaheenuzzamn et al. beside this, lack of irrigation of water facilities in cht region which caused drought condition might be another limitation. table 1. different characters of soybean varieties in hilly region of ramgarh, khagrachari, 2011-12 and 2012-13 varieties plant height (cm) no. of branches plant-1 no. of pods plant-1 no. of seeds pod-1 201112 201213 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 shohag 57.35 55.76 2.00 1.60 13.50 12.94 2.58 2.48 bari soybean-5 58.66 59.42 1.95 2.16 12.75 13.42 2.47 2.36 bari soybean-6 60.00 61.50 2.43 2.28 14.00 13.66 2.56 2.16 lsd(0.05) 3.5 3.76 6.75 0.49 3.07 2.08 0.7 0.16 cv (%) 4.7 5.3 10.9 15.9 9.0 10.8 7.8 6.8 table 2. yield and yield contributing characters of soybean varieties in hilly region of ramgarh, khagrachari, 2011-12 and 2012-13 varieties wt. of seeds plant-1 (g) 1000-seed wt (g) seed yield (t ha-1) 2011-12 2012-13 2011-12 2012-13 2011-12 2012-13 shohag 8.77 7.92 89.90 88.60 0.52 0.50 bari soybean-5 7.50 7.24 90.00 89.00 0.48 0.46 bari soybean-6 6.45 5.58 87.35 88.40 0.58 0.55 lsd(0.05) 2.10 1.10 4.9 5.78 0.28 0.14 cv (%) 3.5 5.4 7.8 8.2 25.09 30.6 results of the present study indicated that soybean bari soybean-6 would be suitable for cultivation in hill region but more trial is needed the variety in the hilly region. references hossain, m. d. and m. a. rahman. 2008. toil beez fasal utpadan briddhir somosya o tar somadhaner loskhe bari udbhabita projukti somuha. in: krishi projukti manual, m. nazim uddin, m. ahmed, m. s. alam, r. u. shamim, s. ullah and k. m. salahuddin (eds), bangladesh agril. res. inst., joydebpur, gazipur. pp.39-43. mondal, m. r. i. and m. a. wahhab. 2001. production technology of crops. oil seed research center, bangladesh agril. res. inst., joydebpur, gazipur. pp.1-10. rahman, l. 2003. studies on the development of varieties, production technology, food and fish feed uses of soybean in bangladesh (bau-usda soybean project bg-ars 107).p.6. microsoft word 13 bangladesh agron. j. 2017, 20(2): 115-122 effect of manureseffect of manureseffect of manureseffect of manures with with with with fertilizers on yield and yield fertilizers on yield and yield fertilizers on yield and yield fertilizers on yield and yield traits of mungbean (traits of mungbean (traits of mungbean (traits of mungbean (vigna radiata vigna radiata vigna radiata vigna radiata l.)l.)l.)l.) m. e. hossainm. e. hossainm. e. hossainm. e. hossain andandandand m. s. islamm. s. islamm. s. islamm. s. islam**** department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, e-mail: (received:received:received:received: 14 december 2017, accepted:accepted:accepted:accepted: 17 january 2018) keywords:keywords:keywords:keywords: bari mung-6, vermicompost, 1000-seed weight and seed yield. abstractabstractabstractabstract an experiment was carried out at the agronomy field of sher-e-bangla agricultural university, dhaka during the period from march to june 2015 (kharif-i season) to find out the effect of different manures along with inorganic fertilizers on yield and yield traits of mungbean varieties. the experiment consisted of two factors: factor a: five levels of manures along with inorganic fertilizers [ t0 = control (no fertilizer or manure), t1 = recommended dose of fertilizer (r) (45 kg urea ha -1 + 100 kg tsp ha-1 + 58 kg mop ha-1), t2 = r + cowdung (3 t ha -1), t3 = r + poultry manure (2 t ha -1), t4 = r + vermicompost (2.5 t ha-1)] and factor b: two mungbean varieties; (v1 = bari mung 5 and v2 = bari mung 6). the experiment was laid out in splitplot design with three replications. the effect of manures along with recommended inorganic fertilizers on yield and yield traits were found significant. the maximum grain yield (1.53 t ha-1) and maximum stover yield (1.88 t ha-1) was recorded from t4 treatment. mungbean variety had also significant influence on yield and yield traits. the maximum seed yield (1.58 t ha-1) was obtained from var. bari mung 6) but maximum stover yield (1.91 t ha-1) was obtained from var. bari mung 5). the combined effects of manures along with recommended inorganic fertilizers and variety were found statically significant on yield and yield traits. the maximum seed yield (2.01 t ha-1) and maximum stover yield (2.61 t ha-1) was recorded from t4v2. there were positive correlations of seed yield with different yield components. it was comparatively stronger correlations in bari mung 5 and weaker in bari mung 6. so, var. bari mung 6 performed the best result with the application of vermi-compost @ 2.5 t ha-1 with recommended dose of fertilizer. introductionintroductionintroductionintroduction mungbean (vigna radiata l.) is an important short duration, drought tolerant pulse crop which is also commonly known as “green gram”. it has an edge over other pulses because of its high nutritive value, digestibility and non-flatulent behavior. average yield of mungbean in bangladesh is very low, which is primarily due to lack of proper methods of cultivation, poor crop stand, imbalanced fertilization, poor plant protection measures and lack of high yielding varieties. the low yield of mungbean besides other factors may partially be due to lack of knowledge about nutrition and modern production technology (hassan, 1997). moreover, lack of attention on fertilizer use is also hampered the lowering of mungbean yields (mansoor, 2007). variety plays an important role in producing high yield of mungbean because different varieties responded differently for their genotypic characters. very recently, with the introduction of some high yielding varieties viz., bari mung-6 and bari mung-5 increasing attention is being paid to the cultivation of this crop in order to mitigate the alarmingly protein shortage in the diet of our people. mungbean is highly responsive to fertilizers and manures. it 116 hossain & islam has a marked response to nitrogen (n), phosphorus (p) and potassium (k). these nutrients play a key role in plant physiological process. cowdung has relatively less n than some other manure, so it can be added directly to the soil without damaging plants. poultry manure is an excellent source of organic fertilizer which is rich in micro and macronutrients. poultry manure also improves nutrient status in soil and at the same time may reduce soil pollution, which developed from the continuous use of chemical fertilizer. vermi-composting is the processing of organic wastes with earthworms. during this process, elements like n, p, k, and ca present in the waste are released and converted, through microbial activity, into forms more soluble and available to plants than those present in the original waste (edwards and burrows, 1988). phosphorus plays a remarkable role in plant physiological processes. it is an essential constituent of majority of enzymes which are of great importance in the transformation of energy in carbohydrate metabolism in different types of plants and is closely related in cell division and seed development. potassium, as a plant nutrient, is becoming increasingly important in bangladesh and a good crop response to k is being reported from many parts of the country. pulse crops showed yield benefits from k application and also improved k supply enhances biological n fixation and protein content of pulse seed (srinivasarao et al., 2003). considering the above facts, the present investigation aimed to find out the optimum doses of manures and inorganic fertilizers for maximizing the yield and yield contributing characters of two selected mungbean varieties. materials and mmaterials and mmaterials and mmaterials and methodsethodsethodsethods the experiment was carried out at the agronomy field of sher-e-bangla agricultural university (sau), dhaka. the experimental site is situated at 23o77' north latitude and 90o30' east longitude. the elevation of the experimental site is 8.0 m above the sea level. the area belongs to the agro-ecological zone -28: (madhupur tract). mungbean var. bari mung-5 (v1) and bari mung-6 (v2) were used in the study. the experiment was laid out in splitplot design with three replications. the experiment consisted of two factors: factor a: five levels of manures and inorganic fertilizers; [t0 = control (no fertilizer or manure) t1 = recommended dose of fertilizer (r) (45 kg urea ha-1 + 100 kg tsp ha-1 + 58 kg mop ha-1), t2 = r + cowdung (3 t ha-1), t3 = r + poultry manure (2 t ha -1), t4 = r + vermi-compost (2.5 t ha -1)] and factor b: two mungbean varieties; (v1 = bari mung 5 and v2 = bari mung 6). the experimental land was opened with a power tiller and subsequently ploughed twice followed by laddering. weeds, stubbles and crop residues were removed. except urea, all manures (cowdung, poultry manure and vermi-compost) were applied along with tsp, mop, gypsum, zinc sulphate and boric acid as per treatments during the final land preparation. the urea was applied at two intervals. first half was applied during final land preparation and rest was applied at 25 das followed by light irrigation. mungbean seeds were sown on 01 march, 2015. healthy seeds of mungbean @ 35 kg ha-1 were sown by hand as uniformly as possible in furrows. seeds were sown in the afternoon and immediately covered with soil to avoid sunlight. line to line distance was maintained 30 cm. gap filling, weeding, application of irrigation water and plant protection measures were taken properly when needed. data on number of pods plant-1, pods length (cm), number of seeds pod-1, 1000-grain weight, seed yield (t ha-1), stover yield (t ha-1), biological yield (t ha-1) and harvest index (%) were recorded and were statistically analyzed following the analysis of variance by using mstat-c computer package program and the treatment means were compared by least significant difference (lsd) test at 5% level of probability. 117 effect of manures with fertilizers on yield and yield traits of mungbean results and dresults and dresults and dresults and discussioniscussioniscussioniscussion effect of manureseffect of manureseffect of manureseffect of manures along with recommended inorganic fertilizersalong with recommended inorganic fertilizersalong with recommended inorganic fertilizersalong with recommended inorganic fertilizers the effect of manures along with recommended inorganic fertilizers on number of pods plant-1, pod length, number of seeds pod-1 and 1000seed weight were found significant (table 1). the maximum pods plant-1 (12.65), pod length (9.36 cm), seeds pod-1 (9.61) and 1000seed weight (37.19 g) were found in t4 [recommended dose of fertilizer + vermicompost (2.5 t ha-1)], which were statistically similar to t3 (regarding pods plant -1), t3 and t2 (regarding pod length and 1000seed weight) and, t3, t2 and t1 (regarding seeds pod -1). the lowest pods plant-1 (9.83), pod length (8.08 cm), seeds pod-1 (8.17) and 1000seed weight (34.32 g) were found in control , which were statistically similar to t1 and t2 (regarding pods plant -1) and t1 (regarding pod length and 1000seed weight) whereas significantly different from all other treatments (regarding seeds pod-1) (table 1). with the increasing rate of vermi-compost, increased number of pods plant-1 were also observed by ashraf et al. (2003), aruna and narsa (1999), mastan et al. (1999), kalita (1989) and reddy et al. (1990); number of seeds pod-1 and 1000-seed weight by channaveerswami (2005), rajkhowa et al. (2002), chinnamuthu and venkatakrishnan (2001) and patil (1998). yields and harvest index of mungbean were also significantly influenced by manures along with recommended inorganic fertilizers (table 1). the treatment t4 (recommended dose of fertilizer + vermicompost 2.5 t ha -1) produced the maximum stover yield (1.88 t ha-1), seed yield (1.53 t ha-1), biological yield (3.41 t ha-1) and harvest index (44.86%), which were statistically similar to t3 for stover yield (1,87 t ha -1), seed yield (1.46 t ha-1) and biological yield (3.33 t ha-1) whereas significantly different from all the other treatments for harvest index. the control treatment produced the lowest stover yield (1.46 t ha-1), seed yield (1,04 t ha-1), biological yield (2.50 t ha-1) and harvest index (41.61%). the values regarding these parameters recorded from t1 and t2 were statistically similar (table 4). similar results were also reported by oad and buriro (2005) in mungbean, roy and singh (2006) in malt barley and aruna and narsa (1999) in soybean regarding seed yield. the positive effect of vermi-compost along with recommended inorganic fertilizers might be due to their ability to improve soil physical properties, which provide favourable soil health and conditions and thereby increased the yield contributing parameters and yield. table 1. effect of manures along with recommended inorganic fertilizers on yield attributes, yield and harvest index of mungbean treatment pods plant-1 (no.) pod length (cm) seeds pod-1 (no.) 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) t0 9.83 b 8.08 b 8.17 b 34.32 b 1.04 c 1.46 c 2.50 c 41.60 d t1 10.68 b 8.43 b 8.88 a 35.28 b 1.27 b 1.60 b 2.87 b 44.25 b t2 10.74 b 8.91 a 9.34 a 35.77 a 1.30 b 1.65 b 2.95 b 44.06 b t3 12.01 a 9.03 a 9.15 a 35.90 a 1.46 a 1.87 a 3.33 a 43.84 c t4 12.65 a 9.36 a 9.61 a 37.19 a 1.53 a 1.88 a 3.41 a 44.86 a lsd (0.05) 1.74 0.79 0.94 1.84 0.22 0.27 0.33 0.46 cv (%) 13.05 9.47 10.12 15.71 7.21 11.58 8.75 3.81 in a column, means with same letter (s) are not significantly different by lsd at 5% level of significance t0: control (no fertilizer or manure), t1: recommended dose of fertilizer (45 kg urea ha -1 + 100 kg tsp ha-1 + 58 kg mop ha-1), t2: recommended dose of fertilizer + cowdung (3 t ha -1), t3: recommended dose of fertilizer + poultry manure (2 t ha-1), and t4: recommended dose of fertilizer + vermi-compost (2.5 t ha-1) 118 hossain & islam effect of varietyeffect of varietyeffect of varietyeffect of variety mungbean variety had significant influence on number of pods plant-1, pod length, seeds pod-1, 1000-seed weight and stover yield, seed yield, harvest index (table 2). the var. bari mung 6 produced higher pods plant-1 (11.80), pod length (8.64 cm), seeds pod-1 (9.18), 1000seed weight (36.30 g), seed yield (1.58 t ha-1) and harvest index (52.14%) whereas lower stover yield (1.45 t ha-1) compared to var. bari mung 5 of which values for corresponding parameters were 10.41, 7.65 cm, 8.16, 35.07, 1.29 t ha-1, 40.31% and 1.91 t ha-1, respectively. the var. bari mung 5 (3.20 t ha-1) and bari mung 6 (3.03 t ha-1) was produced the statistically similar biological yield (table 3). table 2. effect of variety on yield attributes, yield and harvest index of mungbean treatment pods plant-1 (no.) pod length (cm) seeds pod-1 (no.) 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) v1 10.41 b 7.65 b 8.16 b 35.07 b 1.29 b 1.91 a 3.20 a 40.31 b v2 11.80 a 8.64 a 9.18 a 36.30 a 1.58 a 1.45 b 3.03 a 52.14 a lsd (0.05) 1.10 0.50 0.59 1.16 0.14 0.16 ns 3.37 cv (%) 12.39 7.54 8.45 16.58 12.79 12.75 8.46 4.04 in a column, means with same letter (s) are not significantly different by lsd at 5% level of significance v1: bari mung 5, v2: bari mung 6 combined effect combined effect combined effect combined effect of manures along with recommended inorganic of manures along with recommended inorganic of manures along with recommended inorganic of manures along with recommended inorganic fertilizers and varietyfertilizers and varietyfertilizers and varietyfertilizers and variety the combined effects of manures along with recommended inorganic fertilizers and variety were found significant on pods plant-1, pod length, seeds pod-1, 1000seed weight and stover yield, seed yield, biological yield and harvest index (table 3). combination of t2v2 (combination of recommended dose of fertilizer + cowdung @3 t ha-1 and bari mung 6) produced the maximum pod length (9.50 cm), seeds pod-1(10.23), 1000seed weight (38.55 g) and were statistically identical to that of t3v1, t4v1, t0v2, t1v2, t3v2 and t4v2 for pod length; that of t1v1, t2v1,t4v1,t0v2,t3v2, t4v2 for seeds pod -1 and that of t3v1, t4v1 and t4v2 for 1000seed weight. whereas, the lowest values these parameters were found in t0v1 ( combination of no fertilizers and bari mung 5) and were statistically similar to that of t0v2, t1v2 and t2v2 for pods plant-1, that of all the combinations except t2v2, t3v2 and t4v2 for seeds pod -1 and except t2v2 for 100seed weight. on the other hand, the combination of t4v2 (combination of recommended dose of fertilizer + vermicompost @ 2.5 t ha-1 and bari mung 6) produced the highest pods plant-1 (12.78), stover yield (2.61 t ha-1), seed yield (2.01 t ha-1) and biological yield (4.62 t ha-1) and were statically identical to all other treatment combinations except t0v1 for pods plant-1, significantly different from all other treatment combinations for stover yield and biological yield and except t4v1 for seed yield. the combination of t1v2 (combination of no fertilizers with bari mung 6) produced the highest harvest index (56.83%) and was significantly different from that of all other combinations. the combination of t0v1 produced the lowest values for these parameters (table 3). these results are also inconformity with the findings of channaveerswami (2005), patil (1998), abbas et al. (2011), rajkhowa et al. (2002), chinnamuthu and venkatakrishnan (2001), kumar et al. (2002). effect of manures with fertilizers on yield table 3. combined effect of manures along with recommended inorganic fertilizers and variety on yield attributes, yields and harvest index treat ment pods plant-1 (no.) pod length (cm) seeds pod (no.) t0v1 9.19 b 7.93 b 8.01 c t1v1 11.66 a 7.96 b 9.15 a t2v1 12.35 a 8.00 b 8.99 a t3v1 12.34 a 8.93 ab 8.60 bc t4v1 12.31 a 8.81 ab 9.32 a t0v2 10.46 ab 8.73 ab 8.99 a t1v2 11.33 ab 8.56 ab 8.61 bc t2v2 11.05 ab 9.50 a 10.23 a t3v2 12.53 a 9.03 ab 9.74 ab t4v2 12.78 a 9.01 ab 10.08 a lsd (0.05) 2.46 1.11 1.32 cv (%) 12.39 7.54 8.45 in a column, means with same letter (s) are not significantly different by lsd at 5% level of significance t0: control (no fertilizer or manure), t1: recommended dose of fertilizer (45 kg urea ha ha-1 + 58 kg mop ha-1), t2: recommended dose of fertilizer + cowdung (3 t ha dose of fertilizer + moultry manure (2 t ha ha-1) functional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield components there were positive correlations of seed yield with the different yield components. it was comparatively stronger in bari mung 5 and weaker in bari mung 6. the r for pods plant-1 and seed yield in bari mung 5 0.429 [figure 1 (b)]; for seeds pod-1 and seed yield in bari mung 6 0.3967 [figure 2 (b)] mung 5 0.6738 [figure 3(a)] and in bari mung 6 0.1319 [figure 3 (b)]. (a) fig. 1. relationship between pod plant 6 (b) 119 n yield and yield traits of mungbean combined effect of manures along with recommended inorganic fertilizers and variety yields and harvest index of mungbean seeds pod-1 (no.) 1000seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) 8.01 c 35.08 b 1.05 d 1.23 d 2.28 e 46.05 c 9.15 a-c 35.76 b 1.17 d 1.78 bc 2.95 b 39.66 g 8.99 a-c 35.83 b 1.34 cd 1.77 bc 3.11 cd 43.09 f 8.60 bc 36.50 ab 1.29 cd 1.49 cd 2.78 de 46.41 c 9.32 a-c 36.67 ab 1.74 ab 2.13 b 3.87 b 44.96 d 8.99 a-c 35.59 b 1.17 d 1.25 d 2.42 e 48.35 bc 8.61 bc 35.60 b 1.54 bc 1.17 d 2.71 de 56.83 a 10.23 a 38.55 a 1.61 bc 1.77 bc 3.38 c 47.63 b 9.74 ab 35.31 b 1.65 bc 1.61 c 3.26 c 50.61 b 10.08 a 36.96 ab 2.01 a 2.61 a 4.62 a 43.51 ef 1.32 2.61 0.31 0.41 0.47 3.22 8.45 16.58 12.79 12.75 8.46 4.04 in a column, means with same letter (s) are not significantly different by lsd at 5% level of significance recommended dose of fertilizer (45 kg urea ha-1 + 100 kg tsp : recommended dose of fertilizer + cowdung (3 t ha-1), t3: recommende anure (2 t ha-1), t4: recommended dose of fertilizer + vermicompost (2.5 t functional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield componentsfunctional relationship between seed yield and different yield components there were positive correlations of seed yield with the different yield components. it was comparatively stronger in bari mung 5 and weaker in bari mung 6. the r2 value was found and seed yield in bari mung 5 was 0.7547 [figure 1(a)] and bari mung 6 and seed yield in bari mung 5 0.5078 [figure 2(a)] [figure 2 (b)], and for 1000seed weight and seed yield in bari mung 5 0.6738 [figure 3(a)] and in bari mung 6 0.1319 [figure 3 (b)]. (a) (b) 1. relationship between pod plant-1 and seed yield of bari mung 5 (a) and bari mung y = 0.1256x 0.1356 r² = 0.429 0 0.5 1 1.5 2 0 5 10 15 s e e d y ie ld ( t h a -1 ) pod plant-1 119 combined effect of manures along with recommended inorganic fertilizers and variety harvest index (%) 46.05 c-e 39.66 g 43.09 f 46.41 c-e 44.96 d-f 48.35 bc 56.83 a 47.63 b-d 50.61 b 43.51 ef 3.22 4.04 in a column, means with same letter (s) are not significantly different by lsd at 5% level of significance + 100 kg tsp : recommended (2.5 t there were positive correlations of seed yield with the different yield components. it was found and bari mung 6 and seed weight and seed yield in bari (a) and bari mung 15 120 hossain & islam (a) fig. 2. relationship between seed pod mung 6 (b) (a) fig. 3. relationship between 1000-seed weight and seed yield of bari mung 5 bari mung 6 (b) based on the result of the present study it was found that performed the highest seed yield (2.01 t inorganic fertilizer (45 kg urea ha-1 + 100 kg tsp ha at the rate of 2.5 t ha-1 for mungbean production in inorganic fertilizer (45 kg urea ha-1 + 100 kg tsp ha at the rate of 2.5 t ha-1 performed the best result for acknowledgementacknowledgementacknowledgementacknowledgement the authors are very much thankful to ministry of science and t republic of bangladesh, for nst fellowship during 2015 (a) (b) 2. relationship between seed pod -1 and seed yield of bari mung 5 (a) and bari (a) (b) seed weight and seed yield of bari mung 5 (a) and conclusionconclusionconclusionconclusion based on the result of the present study it was found that mungbean var. bari mungbean 6 yield (2.01 t ha-1) with the application of recommended dose of + 100 kg tsp ha-1 + 58 kg mop ha-1) and vermi-compost for mungbean production in kharif –i season. the cumulative effect of + 100 kg tsp ha-1 + 58 kg mop ha-1) and vermi-compost performed the best result for var. bari mung 6 than bari mung 5. acknowledgementacknowledgementacknowledgementacknowledgement ful to ministry of science and technology, the people’s republic of bangladesh, for nst fellowship during 2015-2016. (a) and bari (a) and bari mungbean 6 ) with the application of recommended dose of compost the cumulative effect of compost bari mung 6 than bari mung 5. echnology, the people’s 121 effect of manures with fertilizers on yield and yield traits of mungbean referencesreferencesreferencesreferences abbas, g., aslam, m. ullah, a. malik, z. abbas, m. ali and f. hussain, 2011. potassium sulfate effects on growth and yield of mungbean (vigna radiata l.) under arid climate. int. j. agric. appl. sci. 3 (2): 12-14 aruna, p. and r. s. narsa, 1999. response of soybean (glycine max) to conjunctive use of organic and inorganic sources of nitrogen. indian j. agric. sci. 69 (5): 382 – 383. ashraf, m., m. mueen-ud-din and n. h. warrick, 2003. production efficiency of mungbean (vigna radiata l.) as affected by seed inoculation and npk application. intl. j. agric. biol. 5(2): 179-180. channaveerswami, a. s. 2005. studies on integrated nutrient management and planting methods on seed yield and quality of groundnut. ph.d. thesis, univ. agric. sci., dharwad, karnataka (india). chinnamuthu, c. r. and venkatakrishnan. 2001. effect of integrating inorganic fertilizer with vermicompost and vescular arbuscular mycorrhizae (vam) on the productivity of sunflower. madras agric. j. 88 (7-9): 424 – 427. edwards, c. a. and i. burrows. 1988. the potential of earthworms composts as plant growth media. in: edward, c.a. and neuhauser, e.f. eds., earthworms in waste and environmental management, spb academic publishing, the hague, 2132. hassan, r., 1997. growth and yield response of mungbean to different seed rates and levels of phosphorus. m.sc. thesis, agron. dept., university of agriculture faisalabad, pakistan. kalita, m. m. 1989. effect of phosphorus and growth regulator on mungbean (vigna radiata). indian. j. agron. 34 (2): 236-237. kumar, s., g. r. choudhary and a. c. chaudhari, 2002. effects of nitrogen and biofertilizers on the yield and quality of coriander (coriandrum sativum l.). ann. agr. res. 23 (4): 634-637. mansoor, m. 2007. evaluation of various agronomic management practices for increased productivity of mungbean (vigna radiata l. wilszek). ph.d thesis, department of agronomy, faculty of agriculture, gomal university, d. i. khan. mastan, s. c., s. n. reddy, t. m. m. reddy, m. shaik and s. mohammad, 1999. productivity potential of rice-sunflower-mungbean cropping system as influenced by rational use of phosphorus. indian. j. agron. 44 (2): 232-236. oad, f. c. and u. a. buriro, 2005. influence of different npk levels on the growth of mungbean. crop res. hisar. 50: 40 – 42. patil, b. s., 1998. studies on integrated nutrient management in summer groundnut (arachis hyphogea l.). m. sc. (agri). thesis, univ. agric. sci., dharwad, karnataka (india). rajkhowa, d. j., m. saikia, and k. m. rajkhowa, 2002. effect of vermicompost with and without fertilizer on greengram. legume res. 25 (4): 295-296. reddy, s. n., b. g. singh and i. v. s. rao, 1990. an analysis of dry matter production, growth and yield in mungbean and blackgram with phosphate fertilizer. j. m. maharashtra agril. univ. 15 (2): 189-191. 122 hossain & islam roy, d. k. and singh, 2006, effect of level and time of nitrogen application with and without vermicompost on yield, yield attributes and quality of malt barley (hordeum vulgare). indian j. agron. 51 (1): 40 – 42. srinivasarao, c., a. masood, a. n. ganeshamurthy and k. k. singh. 2003. potassium requirements of pulse crops. better crops int. 17(1): 8 –11. chapter i bangladesh agron. j. 2015, 18(1): 71-80 growth and yield performance of tidal local aman rice as influenced by usg application at non tidal condition s. m. s. abedin1, m. a. mannan1, m. a. a. mamun1,*, g. k. m. m. rahman1 and a. j. mridha2 1bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 2bangladesh rice research institute, gazipur-1701 *corresponding author: aamamunbrri@yahoo.com key words: grain yield, local aman, tidal area, urea super granule abstract an experiment was carried out at research field of bangladesh rice research institute, gazipur to evaluate the performance of tidal local aman rice as influenced by urea super granule (usg) at non-tidal condition. four tidal local aman varieties such as sadamota, razashail, kutiagoni and kalagura were used as planting materials. nitrogen was applied as usg (1.8g) at 10 days after transplanting (dat), 25 dat, before panicle initiation (bpi) stage (date of pi stage of these 4 varieties were identified from previous experience) and no nitrogen (control). the experiment was laid out in a splitplot design where varieties in main plot and usg in sub-plot with three replications. varietals response was significant on plant height, effective tillers hill-1, grains panicle-1 and grain yield. all the yield and yield components were influenced significantly by the time of usg application. higher dry matter was produced by all the varieties when usg was applied at early growth stage (10 to 25 dat) but crop lodges at milking stage due to more vegetative growth resulting increases sterility, decreases grain fertility and yield. on the other hand, when usg was applied at bpi stage grain fertility and yield were increased. the highest grain yield (3.51 t ha-1) was recorded from kalagura when usg applied before panicle initiation stage. so, application of usg at bpi stage in local aman rice in non-tidal condition increased yield resulting higher gross and net return in all varieties. introduction sustainable rice production is a great challenge for the rice grower under climate change condition. low productive tidal submergence ecosystem is one of the major unfavorable agroecological situations in bangladesh (hossain et al., 2002). more than 1.0 million ha of greater barisal and patuakhali districts are inundated up to the range of 6-90 cm for about 4-5 months from june to october (brri, 2004). aman season (june to november) is one of the major crops growing seasons and farmers cultivate local varieties. high yielding varieties cannot survive under tidal ecosystem. locally popular traditional varieties like lothor, lalpyka, kutiagoni, mutha, razashail, sada pajam, lal chikon, sada chikon sada muta, lal muta and moulata etc. are resistant and perform better in tidal areas. due to tidal water movement, farmers do not apply fertilizer in aman season. it is often impossible to follow recommended practices of nutrient management like nitrogen (n) fertilizer because there is a high risk of surface n losses to tidal water. so, the yield of cultivated local rice varieties is low and it is because of low n concentration in the leaf canopy during grain filling period, early senescence of leaves and low rates of photosynthesis (cassman et al., 1995). the increase in amount of n at the booting stage may provide sufficient n to rice plants during the late filling stage. high plant n content delays leaf senescence and therefore increases photosynthetic duration (makino, 72 abedin et al. 2011). the application of n fertilizer has been reported to have a great effect on filling of grain (juan et al., 2006). it has been reported that the amount and time of nitrogen application had tremendous effects on filling and dry matter accumulation in rice (mnzava, 2002). moreover, nitrogen application at pi stage through deep placement of usg (udp) may escape vegetative growth and this may increase the number of grains panicle-1 and better grain filling. increased application of n fertilizer at flowering stage found to increase the yield of rice (cassman et al., 1994). usually, urea super granule (usg) is placed to the rice field at 8-10 days after transplanting that helps to vigorous vegetative growth (ranjith et al., 2008). little research has been done on usg deep placement in local rice varieties in tidal areas of bangladesh. under the above circumstances, the study was undertaken to evaluate the performance of local aman rice varieties in respect of yield and nitrogen use efficiency and to find out suitable time of nitrogen application in local aman rice in agro-climate condition of gazipur. materials and methods the experiment was carried out at agronomy field of bangladesh rice research institute, gazipur during the aman season, 2014. the soil of brri farm was clay loam of shallow brown terrace under madhupur tract (aez 28), with ph 6.2 and low in organic matter (1.2%).the experimental field was ploughed with the help of power tiller followed by laddering to get a well puddled condition. a blanket dose of 16, 35, 10 and 1.8 kg ha-1 of p, k, s and zn were applied as triple super phosphate, muriate of potash, gypsum and zinc sulphate, respectively at final land preparation. the treatments were, factor a: local aman varieties, i. sadamota, ii. razashail, iii. kutiagoni and iv. kalagura; factor b: time of usg (1.8g) application at i. 10 dat, ii. 25dat, iii. before panicle initiation (bpi) stage and iv. no nitrogen (control).the experiment was laid out in split-plot design assisning varieties in main plot and usg in sub-plot with three replications.thirty-days-old seedlings were transplanted maintaining 30 cm 30 cm spacing on 7th august, 2014. intercultural operation like gap filling was done on 15th august, 2014. two hand weeding was done on 22nd august and 10th september, 2014. irrigation water was applied as and when necessary. data on tillering dynamics, spad value, dry matter production, yield and yield components were recorded following standard procedure. grain yield was adjusted to 14% moisture content. agronomic efficiency, partial factor productivity and grain yield efficiency index were calculated using following formulae. i. agronomic efficiency (ae) aen = (gy+ n – gy0 n) / fn where, aen = agronomic efficiency of n; gy+ n = grain yield due to addition of fn; gy0 n = grain yield without addition of n; fn = amount of n applied (kg ha-1). ii. partial factor productivity (pfp) pfpn = gy+ n / fn where, pfpn = partial factor productivity of n; gy+ n = grain yield due to addition of fn; fn = amount of n applied (kg ha-1). iii. grain yield efficiency index (gyei) gyei = plot control in varietiesallfor yieldgrain average plot control in yieldgrain x plot applied n in varietiesallfor yieldgrain average plot applied n in yieldgrain data gathered on different parameters were statistically analyzed and the mean different among the treatments were compared by least significance difference (lsd) test at 5% level of significance. 73 growth and yield performance of tidal local aman rice by usg results and discussion tiller production (no. hill-1) tiller production varied in cultivated varieties due to usg application at different times (table 1). in general, the number of tillers per hill increases with the advance of time upto certain period. maximum number of tillers was recorded at 40 to 60 dat from almost all the studying varieties irrespective of time of usg application. the lowest number of tillers was recorded with var. kalagura from control plot and the highest from var. razashail when usg was applied at bpi at 20 dat of crop. at 40 dat, there was no significant difference among the varieties in case of tiller production. at 60 dat, the highest number of tillers per hill was recorded when usg applied at bpi in var. kalagura. at 80 dat, highest number of tillers was found from var. sada mota and kutiagoni when usg applied at bpi. at 80 dat, the lowest number of tillers was recorded from the var. razashail when usg applied at early crop growth stage (10 dat). number of tillers per hill is most important component of yield. the decrease in tiller number was attributed to the death of some tillers as a result of their failure in competition for light and nutrients (fageria et al., 1997). more number of tillers might be due to the more availability of nitrogen that played a vital role in cell division. table 1. variation of tiller/hill production due to interaction of variety and time of usg application at different days after transplanting (dat) of rice time of usg application variety sada mota razashail kutiagoni kalagura 20 dat 10 dat 6 7 7 6 25 dat 6 6 7 6 bpi 7 8 6 7 control 6 7 7 5 lsd (0.05 ) ns cv (%) 16.3 40 dat 10 dat 20 20 19 19 25 dat 19 20 20 19 bpi 21 21 21 21 control 18 19 19 18 lsd (0.05 ) ns cv (%) 13.2 60 dat 10 dat 18 20 17 21 25 dat 20 21 19 22 bpi 21 22 20 23 control 19 19 16 18 lsd (0.05 ) ns cv (%) 12.6 80 dat 10 dat 16 15 17 17 25 dat 20 17 20 19 bpi 21 19 21 20 cont 14 16 16 15 lsd (0.05 ) ns cv (%) 15.7 bpi = before panicle initiation stage 74 abedin et al. spad values the interaction effect of variety and time of usg application on spad value was not significant at 20 dat (table 2). the highest spad value was recorded with var. razashail during application of usg at bpi stage and lowest from kalagura when usg applied during 10 dat and 20 dat of rice. at 40 dat, the highest spad value (43.23) was demonstrated from kalagura from usg application at 10 dat. the interaction between the variety and the time of usg application was not significant at 40 and 80 dat. at 60 dat, the highest spad value (43.33) was recorded from kalagura with usg application at 25 dat and the lowest (32.93) from the control plot with sada mota when usg applied at 10 dat. the var. sada mota gave the lowest spad value and the highest spad value from kalagura when usg applied at 25 dat and 80 dat. hassan et al. (2009) reported that spad value and nitrogen content showed significant differences under variable nutrient levels and time of urea application. table 2. variation of spad values due to interaction of variety and time of usg application at different days after transplanting (dat) of rice time of usg application variety sada mota razashail kutiagoni kalagura 20 dat 10 dat 36.40 36.19 35.56 32.53 25 dat 34.95 34.21 35.26 34.13 bpi 35.94 36.76 36.86 34.20 control 35.08 35.14 36.16 33.60 lsd (0.05) ns cv (%) 4.8 40 dat 10 dat 39.30 40.87 39.73 43.23 25 dat 40.33 42.17 39.67 42.27 bpi 38.67 40.20 43.20 40.33 control 39.93 40.90 41.83 39.67 lsd0.05 ns cv (%) 7.0 60 dat 10 dat 36.73 37.23 35.67 35.63 25 dat 34.43 36.73 36.70 37.33 bpi 36.83 34.80 35.03 35.67 control 32.93 35.10 34.23 34.80 lsd (0.05 ) 2.74 cv (%) 4.6 80 dat 10 dat 33.23 33.40 33.67 36.50 25 dat 31.13 31.97 33.53 39.30 bpi 33.90 32.13 36.77 36.93 control 34.20 31.33 35.23 36.40 lsd (0.05 ) ns cv (%) 7.1 bpi = before panicle initiation stage dry matter production at flowering stage (g m-2) the interaction between variety and time of usg application was not significant statistically for dry matter production dat (table 3). application of usg at 25 dat produced higher leaf blade dry matter in kalagure (230.96 g m-2) followed by sada mota (228.85 g m-2). the lowest 75 growth and yield performance of tidal local aman rice by usg dry matter was obtained from razsahil when usg applied at 10 dat. on the other hand, sada mota gave maximum leaf sheath dry matter (256. 52 g m-2) when usg applied at 25 dat. stem dry matter was maximum in kalagura in usg application at 25 dat and bpi stage. the var. kutiagoni produced maximum panicle dry matter when usg applied at 25 dat. the total dry matter was maximum when usg applied at 25 dat in kalagura (833.61 g m-1) followed by sada mota (826.90 g m-1) (table 3). the lowest dry matter was obtained from razashail in control plot. crop attributes such as leaf area index and shoot dry matter were dependent on the applied nitrogen level applied and time of application. the higher growth resulting from increased nitrogen application could be attributed to the effects of nitrogen on cell division and elongation, synthesis of amino acids as well as its impact on some physiological processes favoring growth. dry matter production exhibited a greater response to late-season application of n (fageria and baligar, 2001). table 3. interaction of variety and time of usg application on dry matter production (g m-2) at flowering stage time of usg application variety dry matter (g m-2) sada mota razashail kutiagoni kalagura leaf blade 10 dat 186.77 86.11 181.15 205.10 25 dat 228.85 113.80 108.85 230.96 bpi 162.73 92.57 126.23 221.23 control 159.82 99.50 104.68 180.59 lsd (0.05 ) ns cv (%) 21.2 leaf sheath 10 dat 205.70 77.82 140.48 236.03 25 dat 256.52 72.64 158.38 223.31 bpi 203.12 91.15 133.03 224.36 control 171.01 82.65 112.36 199.88 lsd (0.05 ) ns cv (%) 25.2 stem 10 dat 178.92 135.88 187.86 219.47 25 dat 221.60 199.14 177.46 271.68 bpi 218.24 150.52 143.14 271.86 control 151.51 129.75 136.48 220.63 lsd (0.05 ) ns cv (%) 20.5 panicles 10 dat 102.65 95.85 141.62 116.75 25 dat 146.93 117.79 180.23 107.64 bpi 136.23 118.96 197.58 113.50 control 129.23 83.324 155.10 115.11 lsd (0.05 ) ns cv (%) 18.7 total 10 dat 674.06 395.66 669.38 777.37 25 dat 826.90 503.38 677.32 833.61 bpi 754.96 453.21 606.50 790.96 control 611.28 395.13 509.55 716.23 lsd (0.05 ) ns cv (%) 15.4 bpi = before panicle initiation stage 76 abedin et al. crop lodging at milking stage 0 10 20 30 40 50 60 70 10 dat 25 dat bpi control time of usg application l o d g in g a t m ilk in g s ta g e ( % ) sadamota razashail kutiagoni kalagura fig. 1. variation of crop lodging at milking stage due to interaction of variety and time of usg application all varieties were lodged at milking stage. the lodging was the maximum when usg applied at 10 and 25 dat but more than 40 % plant lodged at 10 and 25 dat but less than 20% plant lodged when usg applied at bpi stage (fig. 1). yield and yield contributing characters variation of 1000 grain weight, grains panicle-1, panicle m-2, grain yield was not statistically significant (table 4) due to interaction of variety and time of usg application. numerically, 25 dat of sada mota gave the highest 1000-grain weight (33.20g) followed by the bpi of sada mota (32.29) whereas lowest from the control plot of var. kutiagoni. the number of grains per panicle varied from 83 to 135 where maximum number of grains per panicle (135) was found from kutiagoni at 10 dat followed by kutiagoni at bpi but var. kalagura and 10 dat combinations showed the least number of grains per panicle (83). the maximum number of panicle per m-2 (201) was recorded from kalagura at 10 dat followed by kalagura 25 dat (193) whereas lowest from control plot of var. kutiagoni (112). the number of panicles per unit area depends on environmental conditions during tiller bud initiation and subsequent development stages. grain yield varied from 2.23 to 4.02 t ha-1 where bpi of var. kalagura gave the maximum yield (4.02 t ha-1) followed by bpi of sada mota (3.90 t ha-1). control plot of razashail yielded the lowest grain yield (2.23 t ha-1). the variation in grain yield with nitrogen fertilization varied from 66 to 93% depending on genotypes (fageria et al., 2004). it was found that application of nitrogen improves various crop parameters like 1000grain weight, more productive tillers and grain yield thus resulting in higher yields (chaturvedi, 2005). agronomic efficiency agronomic efficiency was significantly varied due to interaction of variety and time of usg application (table 5). agronomic efficiency varied from 20.88 to 49.75.the maximum agronomic efficiency (49.75) was recorded from kalagura during bpi stage followed by agronomic efficiency (44.03) kutiagoni at bpi while the lowest agronomic efficiency (20.88) 77 growth and yield performance of tidal local aman rice by usg from sada mota during 10 dat (table 5). agronomic efficiency in low land rice in the tropics to be in the range of 15 to 25 kg grain produced per kg of applied n (yoshida, 1981). table 4. interaction of variety and time of usg application on yield and yield components of rice time of usg application variety 1000-grain weight (g) sada mota razashail kutiagoni kalagura 10 dat 29.58 25.83 26.71 30.35 25 dat 33.20 24.17 29.28 27.23 bpi 32.29 26.36 27.51 27.27 control 30.40 25.04 23.75 26.20 lsd (0.05 ) ns cv (%) 9.2 no of grains panicle-1 10 dat 105 97 135 83 25 dat 96 86 102 97 bpi 113 91 126 117 control 95 85 106 94 lsd (0.05 ) ns cv (%) 15.3 no of panicle m-2 10 dat 129 182 148 201 25 dat 142 175 163 193 bpi 152 150 154 190 control 125 125 112 140 lsd (0.05) ns cv (%) 12.7 grain yield (t ha-1) 10dat 3.39 3.36 3.18 3.75 25 dat 3.67 3.32 3.60 3.69 bpi 3.90 2.97 3.79 4.02 control 2.78 2.23 2.51 2.57 lsd (0.05 ) ns cv (%) 7.5 dat = days after transplanting, bpi = before panicle initiation stage, table 5. variation of agronomic efficiency due to interaction of variety and time of usg application time of usg application variety agronomic efficiency sada mota razashail kutiagoni kalagura average 10 dat 20.88 38.81 23.00 40.46 30.78 25 dat 30.57 37.34 37.48 38.34 35.93 bpi 38.44 25.36 44.03 49.75 39.39 average 29.96 33.84 34.84 42.85 lsd (0.05 ) variety (v) 8.86 treatments (t) ns `v t 15.36 cv (%) 25.1 dat = days after transplanting, bpi = before panicle initiation stage, 78 abedin et al. partial factor productivity the partial factor productivity was the highest with kalagura variety when usg applied bpi and the lowest from razashail when usg applied at 10 dat (table 6). matsuo et al. (1995) reported that the partial factor productivity for rice straw is high in the early growth stages and reaches the peak more quickly if more n is provided. matsuo et al. (1995) also reported that the extent of nitrogen’s contribution to rice yield correspond to the development of the growth pattern of the rice plant. table 6. effect of time of urea super granule application on partial factor productivity of rice. time of usg application variety partial factor productivity sada mota razashail kutiagoni kalagura average 10 dat 116.67 115.71 109.46 129.07 117.74 25 dat 126.38 114.29 123.95 126.95 122.89 bpi 134.20 102.30 130.42 138.35 126.35 average 125.77 110.78 121.30 131.46 lsd (0.05 ) variety (v) 8.86 treatments (t) ns v t 15.35 cv (%) 7.3 dat = days after transplanting, bpi = before panicle initiation stage, cost and return from the application of usg at different time cost for applying usg was varied from tk. 4075.0 to tk. 4425.0 ha-1 (table 7). at the time of usg application during 10dat, it required 7 labors @ tk. 350.0 day-1and 65.0 kg usg @ tk.25 kg-1 and the total cost was tk. 4075.0 ha-1. at 25dat and bpi one additional labor was needed. so, the cost was tk. 4425.0 ha-1 during 25dat and bpi. but there was no cost in control plot for usg application. the highest gross return was obtained from bpi by tk.73110.0 ha-1followed by 25 dat and 10 dat. the lowest gross return tk. 52660.0 ha-1 was found from control plot.net return of 10dat, 25dat and bpi was tk. 64505.0, tk. 66965.0 and tk. 68685.0 ha-1, respectively. the highest profit over control was tk. 16025.0 ha-1 from bpi followed by 25 dat and 10 dat. table 7. cost and return from the application of usg at different time items time of usg application 10 dat 25 dat bpi control amount of urea (kg. ha-1) 65 65 65 0 cost of urea (tk. ha-1) 1625.00 1625.00 1625.00 0.00 labor needed for fertilizer application (man-day) 7 8 8 0.00 labor cost (tk. ha-1) 2450.00 2800.00 2800.00 0.00 total cost (tk. ha-1) 4075.00 4425.00 4425.00 0.00 grain yield (tha-1) 3.42 3.57 3.67 2.52 return from yield (tk. ha-1) 58140.00 60690.00 62390.00 42840.00 straw yield (tha-1) 5.22 5.35 5.36 4.91 return from straw (tk. ha-1) 10440.00 10700.00 10720.00 9820.00 gross return (tk. ha-1) 68580.00 71390.00 73110.00 52660.00 net return (tk. ha-1) 64505.00 66965.00 68685.00 52660.00 profit over control (tk. ha-1) 11845.00 14305.00 16025.00 cost of urea = tk. 25.00 kg-1, labor cost = tk. 350.00 man-day-1, paddy price = tk.17.00 kg-1, straw price = tk. 2.00 kg-1. 79 growth and yield performance of tidal local aman rice by usg cost and return from different local aman varieties total cost was the same for four varieties that was tk. 4075.0 ha-1. the highest gross return was obtained from kalagura by tk. 72870.0 ha-1followed by sada mota and kutiagoni (table 8). the lowest gross return by tk. 58050.0 ha-1 was found from razashail. net return of different varieties varied from tk. 53975.0 ha-1 to tk. 68795.0 ha-1. the highest net return was obtained from kalagura by tk. 68795.0 ha-1 followed by sada mota and kutiagoni. the lowest net return by tk. 53975.0 ha-1 was found from razashail (table 8). inspite of the same cost the net return was highest in case of kalagura because of its higher yield. table 8. cost and return from different local aman vareties items variety sada mota razashail kutiagoni kalagura amount of urea (kg. ha-1) 65 65 65 65 cost of urea (tk. ha-1) 1625.00 1625.00 1625.00 1625.00 labor needed for fertilizer application (man-day) 7 7 7 7 labor cost (tk. ha-1) 2450.00 2450.00 2450.00 2450.00 total cost (tk. ha-1) 4075.00 4075.00 4075.00 4075.00 grain yield (tha-1) 3.43 2.97 3.27 3.51 return from yield (tk. ha-1) 58310.00 50490.00 55590.00 59670.00 straw yield (tha-1) 5.59 3.78 4.87 6.60 return from straw (tk. ha-1) 11180.00 7560.00 9740.00 13200.00 gross return (tk. ha-1) 69490.00 58050.00 65330.00 72870.00 net return (tk. ha-1) 65415.00 53975.00 61255.00 68795.00 cost of urea = tk. 25.00 kg-1, labor cost = tk. 350.00 man-day-1, paddy price = tk.17.00 kg-1, straw price = tk. 2.00 kg-1. selection of n efficient varieties the highest grain yield efficiency index (gyei) was obtained from the variety kalagura (table 9). the gyei value of kalagura is 1.10 followed by sada mota (1.01). the grain yield efficiency index of cultivated varieties razashail and kutiagono were 0.80 and 0.99, respectively. table 9. grain yield efficiency index local aman varieties varieties yield in n treated plot average yield in control plot average gyei sada mota 3.65 3.55 2.50 2.52 1.01 razashail 3.22 2.23 0.80 kutiagoni 3.52 2.51 0.99 kalagura 3.82 2.57 1.10 gyei: grain yield efficiency index conclusion from the findings of this experiment it may be concluded that the var. kalagura was found most efficient varieties in respect of yield and nitrogen use efficiency. application of n through usg before panicle initial stage increased grain fertility and yield. so, application of usg before panicle initiation stage might be recommended for increased yield and higher net return in cultivating local aman rice varieties. 80 abedin et al. references brri (bangladesh rice research institute). 2004: annual report 2003-2004. brri, gazipur-1701. pp. 37-39. cassman, k.g., s.k. de datta, d.c.olk, j.m. alcantara, m.i. samson, j. p. descalsota and m.a. dizon.1995. yield decline and nitrogen economy of long-term experiments on continuous, irrigated rice systems in the tropics. pages: 181-222 in: soil management: experimental basis for sustainability and environmental quality. r. lal and b. a. stewart, eds. lewis/crc: boca raton, fl. chaturvedi, i. 2005.effect of nitrogen fertilizers on growth, yield and quality of hybrid rice. j. central european agric. 6:611-618. fageria, n. k, a. b. santos and v. c. baligar. 1997. phosphorus soil test calibration for lowland rice on an inceptisol. agron. j. 89: 737-742. fageria, n.k. and v.c. baligar. 2001. lowland rice response to nitrogen fertilization. communications in soil science and plant analysis. 32:1405-1429. fageria, n. k., m. p. barbosa filho, l. f. stone and c. m. guimaraes. 2004. phosphorus nutritionof upland rice. in: phophorus in brazilian agriculture, t. yamada and s. r. s. abdalla, eds., 401-418. piracicaba, sao paulo, brazil: brazilian potassium and phosphate institute. hassan, m. s., a. khair, m. m. haque, a. k. azad, a. hamid. 2009. genotypic variation in traditional rice varieties for chlorophyll content, spad value and nitrogen use efficiency. bangladesh j. agril. res. 34(3): 505-515. hossain, m. a., b. c. roy, s. s. haque, m. a. i. khan, a. w. julfiquar. 2002. potentiality of hybrid rice in the south central region of bangladesh. hybrid rice in bangladesh, progress and future strategies. bangladesh rice research institute, pp: 51-52. juan, c., w. zhong, c. gang and m. yi-wei. 2006. effects of nitrogen fertilizer treatments on filling and respiratory rate of caryopsis in rice. rice science. 13: 199-204. makino, a. 2011. photosynthesis, grain yield, and nitrogen utilization in rice and wheat. plant physiol. 155: 125–129. mnzava, m. m. w. 2002. nitrogen absorption rate at different growth stages in relation to grain production of lowland rice. ph d thesis, los banos, philippines: university of philippines. ranjith, s., t. dunn, d. wornes and k. bechaz. 2008. timing of nitrogen applications for rice. irec farmers’ newsletter, no. 177, summer 2007-08. yoshida, s. 1981. fundamentals of rice crop science. irri, los banos. philippines. p. 269. microsoft word final.doc � �������� ��� �������������������������� ���� �!�"#�� ����� �!�"#�� ����� �!�"#�� ����� �!�"#�� ��������$���$���$���$����%�&�' ��%%�&�' ��%%�&�' ��%%�&�' ��%����()*()*()*()*�������'$#�+ ����'$#�+ ����'$#�+ ����'$#�+ �����$"$"$"$"�������� � � � � � � � � �����$#���$�'%�$#���$�'%�$#���$�'%�$#���$�'%���� ���� !������� �,��!������� �,��!������� �,��!������� �,��������!��!���� ,����!��!���� ,����!��!���� ,����!��!���� ,��������!��!��(��-���!��!��(��-���!��!��(��-���!��!��(��-�....��!��� ,����!��� ,����!��� ,����!��� ,��������������)����/����)����/����)����/����)����/0000���� ��10)2-��3-4-2� 44-2� ��)��-� �)2-��3-4-2� 44-2� ��.� -�2-5���)2-��3-4-2� 44-2� �� ��%�����$��+����-������� ��)2-��3-4-2� 44-2� ��&� 3�6 �3���� 3�%-7-�������$��*�8-59 ��� #� � 5���-����93 � ���4 �3����-�:�,�-��2�,���� ;�/�<� � �;�/�<� � �;�/�<� � �;�/�<� � ��()*��55�-2�3� ��6� �� -2�� ���� �6 3 �23�6 3 �23�6 3 �23�6 3 �23���� ���� �� 3 -���<� � 2���923��� �3� 3 �� �)�%� -3��� ������� ����!'+� -3���* �3�-��� +����-�� �9 -��� ������������������.�3��3� 3�3 ��5� 4� ,��2���4�3 �����$���7���5���()*��55�-2�3� � -�� 6� �� -2�� ���� 3�� 4-��� �93� 3 �� �2���,-2� 5� 4� ,��2�� �4� 3 ��()*� �55�-2�3� � -�� 3 �� 4� ,� =� 4-����� + �� ���$� ��7���5��� ()*� �55�-2�3� � <� � 3� 3��� ���-� 3� 3 �� ()*� �55�-2�3-��� 6/� ���� ���� 3 �� 2��7��3-����� ,�3 ��� �4� � ��9�� � 9 ��� �55�-2�3-���� + �� �7� ���� -� � �� �-��/-��������0�3� �������������3� ������4�3<��/�� �<� ���63�-����4 �,� 3 ��5��3��4�()*��55�-2�3-���<-3 ����$��55�-2�3� �-��3 ��6�3 ���2�3-�� �� � 5�23-7��/���+ �� -� � 3�� � � �39 ����������+>�� ����1����?��+>�� ���������� � �,� �-���@�.�@�+>�� ��������@��@��+>�� ������9 -���������������������.�<� ���63�-���� 4 �,� 3 ��5��3 � 3 ��3��� <-3 � ()*� 6/� ���$� �55�-2�3� � �3� 3 �� �)�%� -3�� ������� ����!'+� -3�� * �3�-���� � 5�23-7��/�� �-���� �44-2-��2/� �4� ���$� ()*� �55�-2�3� � ���� ���� �55�-2�3-��� <� � ������� � ��� ���� ������ � ���� � 5�23-7��/�� ���$� ()*� �55�-2�3� � �7��� 3-,�� ���@0a� 2�,5� ���3��3 �3��4� �����55�-2�3-����4�()*��-��6� �� -2��4-�����$3��� �� �7�����6� �2� 3� ���-� 3� 3 �� ()*� �55�-2�3-��� 6/� ���� ���� ��92� � ..a� 9 ��� �7� � 3 �� � ��9�� � 9 ��� �55�-2�3-���-��2��7��3-�����,�3 ����� � $�3 ��923-��$�3 ��923-��$�3 ��923-��$�3 ��923-������ ���� ( ��� � 3 �� ,�-�� �9 2� � �4� "� 4� 3-�-8� �� "-3 ����� � ��� -,5� 3��3� �93 -��3� ���,��3� 4� � -2�� 5 ��923-����$3���������-����2 ������7� /�2 �5�-���� ���b9��3-3/���,����3 ��4� 3-�-8� ��3 ��9 �� �44-2-��2/� �4� �-3 �����9 � 4� 3-�-8� � � ��<� 3� �9�� 3�� -3 � 7� -�9 � �� � �� "� �� � 5 �2� � � � �� �,,��-��7���3-�-8�3-�������-3 -4-2�3-���� 9��44�� ��5��������2 -�������,��/��3 � �<�/ �� ��/���� �0a��4�3 ��3�3����55�-���"�4� 3-�-8� �2���6�� �2�-7���6/�3 �� -2��5���3�����$���������+ ����<���7��� �4�"�9 ���6/� -2��5���3������ ���/�2�9 ���-3 � 9����� � �-��3 �� �-�c<�3� c5���3�2�,5��d� / 3�,�� + �� ��39 �� ���� ��� ��� �4� �� � ��5���� 95��� �-�� ���� 2�-,�3-2� 2���-3-�� �� �-3 �����9 � 4� 3-�-8� � ���� 4�����<�3� �,�����,��3�5 �23-2� ��!��/��44� 3 � �7��6����,���� 3�� -,5 �7�� 4� 3-�-8� �9 �� �44-2�2/� -�� ��<����� -2�� 5 ��923-���� �,���� 3 �,� �55�-2�3-��� �4� 9 ��� 95� � � ��9��� �()*�� � 3 ����/�2�� -�� ���3��6�����-,5� 3��3���3� ��3-7��3 �3�-�2 �� ��3 ���44-2-��2/��4�"��6�93�����0a� ������ ��-�2 �� ��3 ��/-����6/��0���a�����$���������()*���7��..���a� -� � �� �-��/-����3 ��� 5 -�����9 ������� �7���.�?��>��9 ��� ����< -2 �<� �.��.�a� ��<� � 3 ������$� �2�,,������ �3���e�b9���3���������.����( ���-��3 ��4� ,��4�()*��( ���)95� �* ��9���� � �6����5 �7���3��6�� 95� -� �3��5 -�����9 ���-������� 5�23 ��$3���55�-���-��3 �� -2��4-�������/�4� �����3-,���43� ���3����� ��/ ��4�5���3�3-����4� ����-�� �����-3�2��3 -693� �4� �3 ��< ����� �<-���5� -����4� -2���� %��5� 5��2�,��3� �4�()*� -�� 3 �� ��3� 8���� �� ��2��� 3 �� 4� 3-�-8� � 9 �� �44-2-��2/� �4� -2��< -2 � �44� ��� ��7��,��3��� ���� �2���,-2� 6���4-3 � �$���$�� ������� %�5���-��� ��� �� �� 2�-,�3�� ���� �-3 �����9 ������5�5��2���()*�2��� �7���4�9 ���4� 3-�-8� ��4�95�3��@0a�<-3 �����7� �����4�..a� ����-�2 �� ��� �-��/-��� �95�3��0�a�<-3 �����7� �����4��0a�3����a��7� �3 �� �,���,�9�3��4� ��� �� �,����3����� 5�-3��55�-����-3 ������ �5 -�����9 ����� 5�2-���/�-��3 ����<� � ������4��-3 ����� �3� ��)�7��3����� )3��������??����e����5��2�,��3��4�9 ��� 95� �� ��9��3� ��4���.�� -8��-�3�� �-���4�4�����<�3� � � � � 9�3���-���� ��� ��4�"��� ��3� �"� �2�7� /����� -� � �/-����3 ���3 ��2��7��3-�����"��55�-2�3-��� ,�3 ���� (�4� 39��3��/�� 4� ,� � �7�� ��3� 6���� �6��� 3�� �d3 �23� 6���4-3� 4 �,� 3 � �� 4-��-�� �� 5 -,� -�/�� 6�2�9 ��� 3 �/� �7�� ��� 9-3�6��� 4� 3-�-8� � 5��2�,��3� �b9-5,��3�� %��5� 5��2�,��3� 6/� ���� �b9� �,� ����6� �����2� 3 ��()*��55�-2�3-���6/� ����� ��6� �-�3�� -7������7� /� ��<� -���������3������� �c<� >��/��)�7��3��3�������??����+�� ��7��3 ��5 �6��,�-�����5�5��2�,��3��4� 9 �����!�����-��� -���%-7-����4����$� � ���7���5������()*��55�-2�3� �4� �59����� -2��4-���� < -2 ���-� 3�-��<�-� 3��?�>������� �b9� ����/���3�����0� �9 �4� �����6���()*��55�-2�3-��� �f� �6��3���������������� ,�!�2 -�� /������� 3 � 7� 3�� �2� ����-��� -�����!����%-7-����4� ���$��� ��,��-4-���3 ��()*��55�-2�3� �4� �7� -�6��� �<� 5�2-��������0�2,�� ��92���<�-� 3�4 �,� ?�3��@�>��< -2 �4-����2�5�2-3/������44-2-��2/�<� �����.?� �� ���������a��e�b9���3���������.6���� + ���55�-2�3� ����� �,� ��3� 3 �-��4� ,� =�4-����2���-3-����+ �3 -���<� �9��� 3�>���3��3� 3�3 �� 4-���� 5� 4� ,��2�� �4� 3 �� ()*� �55�-2�3� � ��7���5��� �3� ���$� ���� 3�� 4-��� �93� 3 �� �2���,-2� 5� 4� ,��2���4�3 ���55�-2�3� �� ���� !�3� -�� �����!�3 �� !�3� -�� �����!�3 �� !�3� -�� �����!�3 �� !�3� -�� �����!�3 �� ���� ���� + ��3 -���<� �2���923����3�3 ���)�%� -3��������������3 ��!'+� -3��* �3�-���+����-���9 -�������� �������������.�3��3� 3�3 ��5� 4� ,��2���4�3 �����$���7���5���()*��55�-2�3� �-��6� �� -2��-�� 3 �� 4� ,� =� 4-����� $3�<� � ��-���93� -���#���� -���<-3 � -d��5� ��� �5�-2�3-�� � �4� ,� ���+ ��� 3 ��3,��3 � <� �� 7-8�� +�g� ()*� �55�-2�3-��� ��7���5��� 6/� ���$� ()*� �55�-2�3� �� +�g� ()*� �55�-2�3-���6/� ��������+.g�� -�����9 ����55�-2�3-���-��2��7��3-�����,�3 ����+ ��9�-3�5��3� -8�� <� ���,�d���,�����5���3� 5�2-���<� ��02,�d��02,��$��2��7��3-����� / 3�,��� ��9�� �9 ���<� � �55�-��� :� �@�� >�� ���� -�� 3<�� -� 3���,��3 � � � 3�5� � � � < � �� 3<��3 �� �3� �.� ��/ � �43� � 3 �� 5���3-��� �%�+������ � 3�����3 ���3�.0�%�+��f -���� �2�,,�������� ���4�9 ���4� �6� �� -2�� � � ()*� ���0� >�� ����� ..a� �� � 3 ��� 3 �� �2�,,������ 5 -����� 9 ���� <� � �55�-��� 6/� 3 �� �55�-2�3� � ��2�� �3� ��%�+�� 3 � � 4� 3-�-8� � <� �� �55�-��� � � �2�,,����3-��� -�� 6�3 � 3 �� 3<�� 3 ��3,��3 ��+ �� -2��7� -�3/����$�� ���?�<� �9 ���� �3 ��5���3-���,�3� -����+ �� -2�� ����-�� � <� �� 3 �� 5���3��� �9 -��� ����0� ���9� /�� ����� ���������� ��6 9� /�� ���.� �3� 3 �� �)�%� -3��� ������� �����9 -����@�.�� ���9� /���������������@���6 9� /�����.��3� 3 ��!'+� -3��* �3�-��� � 5�23-7��/�� $�3� 29�39 ��� �5� �3-�� � 92 � � � <���-���� ��5� 4-��-���� -��3-���� ��� �� ���� �3 � � 5� 3�,�����,��3 �<� �� ����� � � ����< ��� ��2� � /�� + �� 2 �5�<� � � 7� 3��� �9 -��� ����0� !�/���������������0��9�������.��3� 3 ���)�%� -3���������������9 -���.����!�/����������� ����@� !�/�� ���.� �3� 3 �� !'+� -3�� * �3�-��� + �� ��3�� ��� �-44� ��3� 5���3� 2 � �23� � ���� /-���� 2�,5����3�<� �� �2� ����5��3�<������<� ������/8��� 3�33-2���/�9 -���# �5�)3�3�5�2>������ ���� �� 9�3 �����%29 -���� 9�3 �����%29 -���� 9�3 �����%29 -���� 9�3 �����%29 -������ ���� h-��������/-�����33 -693� �<� �� -��-4-2��3�/� -�4�9��2���6/� 3 ��9 ����55�-2�3-���,�3 ��� �+�6����� ���� ���� + �� ����� 3� � 5���3 � � �?.�0�� 2,� ���� ?.��@� 2,�� <� �� �6 � 7��� -�� 3 �� 5��3� �4� ()*� �55�-2�3-���<-3 ����$��55�-2�3� �����3 �� � 3� 3��5���3 ����?�..�2,�����?��@��2,��<� ��4�9��� -�� � ��9�� � 9 ��� -�� 2��7��3-����� ,�3 ��� �3� 3 �� �)�%� -3�� ������� ���� !'+� -3�� * �3�-��� � 5�23-7��/��+ ��,�d-,9,� 4-������ �-� ��9,6� �5��-2����� ���.�@��������.�.���<� ���63�-���� 4 �,� 3 �� 5��3� �4� ()*� �55�-2�3-��� <-3 � ���$� �55�-2�3� �� < -��� 3 �� 5��3� <-3 � � ��9�� � 9 ��� -�� 2��7��3-�����,�3 ���5 �7-����,-�-,9,��9,6� ��4�� �-� �5��-2������?0��.�������.��?���3�6�3 � 3 ����2�3-�� ��)-��-4-2��3�/�3 �� -� � 3������� �-��<�-� 3�����?.����������@�����<� �� �2� ���� 4 �,� 3 �� 5��3� �4� ()*� �55�-2�3-��� <-3 � ���$� �55�-2�3� �� < -��� 3 �� 5��3� <-3 � � ��9�� � 9 ��� -�� �?� �� 4� ,��2���4�()*��55�-2�3� � 2��7��3-�����,�3 ���5 �7-����,-�-,9,��9,6� ��4������� �-� �<�-� 3� ����@����������������� �3�6�3 �3 ����2�3-�� �� � 5�23-7��/��+ �� -� � 3��7� ����� �-��/-��������0�3� �������������3� ����� <� ���63�-����4 �,�3 ��5��3��4�()*��55�-2�3-���<-3 ����$��55�-2�3� ������7� ������<� 3�/-���� �@���� 3� ���� ����@���� 3� �����<� �� -�� 3 ��5��3� �4� � ��9�� � 9 ��� -�� 2��7��3-�����,�3 ��� �3� 3 �� �)�%� -3�� ������� ���� �3� 3 �� !'+� -3�� * �3�-��� � 5�23-7��/�� � � 3 �� �9,6� � �4� 4-����� � �-� � 5��-2����� ���� ������ �-� � <�-� 3� <� �� -� � � -�� 3 �� 5��3� �4� ()*� �55�-2�3-��� <-3 � ���$� �55�-2�3� ��3 �� -� � �/-�����63�-����-��3 �3� / 3�,��i9 3-4-����$��2� 3����� �39 ������/ ��+�6���.� ��������3 �� -� � 3�� � � �39 �������������+>�� ������������?�����+>�� ���������� � �,� �-�� �@�.�@���� +>�� ���� ���� @��@����� +>�� ����� <� �� �63�-���� 4 �,� 3 �� 3 ��3,��3� �4� ()*� �55�-2�3-��� <-3 � ���$� �55�-2�3� � �3� 3 �� �)�%� -3�� ������� ���� �3� 3 �� !'+� -3�� * �3�-��� � 5�23-7��/��+ ����<� 3�� � � �39 ������0������+>�� ����������.�.�����+>�� ���������� � � ,� �-�� ��00�.���� +>�� ���� ���� �.��0���� +>�� ����� <� �� �63�-���� 4 �,� 3 �� 5��3 � < � �� � ��9�� �9 ���<� ��55�-���-��2��7��3-�����,�3 ����3�3 ��6�3 ���2�3-�� ��� � +�6������h-����5� 4� ,��2���4��� �� -2������$�� ���?��� �-�4�9��2���6/����$�()*��55�-2�3� �������� �3�3 ���)�%� -3�����������+����-���9 -���������������������.� + ��3,��3 � ��( ����55�-2�3-���,�3 ���� ����3� �-� 3�� �2,�� �-����� � �-� � 5��-2����� ������ ������ � �-�� <3������ * �-��/-�����3� ����� )3 �<� /-����� �3� ���������� �.� ����� ��� �7� ���� +�g�()*��55�-2�3-���<-3 ������ ����������$��55�-2�3� � ?.�0�� ��.�@�� ���?.� @���� ���0� ���0� ��..� +�g�()*��55�-2�3-���6/�� ������� ���� ?����� ����@.� ����.� @�@�� ���0� @�?�� ���@� +.g�* ��9�� �9 ���<-3 � �������2��7��3-�����,�3 ��� �?�..� ?0��.� ���@�� 0��?� @�.�� @���� @�0�� ')%����0����� ��..� ���0� ����� ����� ��.�� �� ����� #&��a����� ����� .���� ����� 0���� .���� �� ��0�� � � +�6�����h-����5� 4� ,��2���4��� �� -2������$�� ���?��� �-�4�9��2���6/����$�()*��55�-2�3� ��3� 3 ��!'+� -3��* �3�-���+����-���9 -���������������������.� + ��3,��3 �� �( ����55�-2�3-���,�3 ���� ����3� �-� 3�� �2,�� �-����� � �-� � 5��-2����� ������ ����� � �-�� <3�� ����� * �-��/-�����3� ����� )3 �<� /-����� �3� ����� ����� �.� ����� ��� �7� ���� +�g�()*��55�-2�3-���<-3 �� ����������$��55�-2�3� � ?.��@� ��.�.�� ���@�� @�?@� ����� ����� ����� +�g�()*��55�-2�3-���6/�� ������� ���� ?.��?� �����.� ������ @���� ���0� @�?.� ����� +.g�* ��9�� �9 ���<-3 � �������2��7��3-�����,�3 ��� ?��@�� ��.��?� ������ @���� 0�?.� @���� @�@�� ')%����0����� ��0�� 0�.�� ����� ����� ����� �� ��@.� #&��a����� ��.�� .���� .�0�� 0���� .���� �� ����� ��� �� �,����3����� +�6���.��#� 3����� �39 ������/ ��4��� �� -2������$�� ���?��5 ��923-���� �-�4�9��2���6/����$� ()*��55�-2�3� ��3�3 ���)�%� -3����������+����-���9 -���������.� + ��3,��3 �� �( ����55�-2�3-���,�3 ���� * � � �39 �� �+>�� ����� +�3���7� -�6���2� 3� �+>�� ����� * � �,� �-�� �+>�� ����� +�g�()*��55�-2�3-���<-3 ����$�� ��������55�-2�3� � ������� 0@�@�� @�.�@� +�g�()*��55�-2�3-���6/� ���� ���.��� 0?0��� 0��.@� +.g�* ��9�� �9 ���-��2��7��3-������ �������!�3 ��� ���0��� 0�?@�� �00�.� � +�6������#� 3����� �39 ������/ ��4��� �� -2������$�� ���?��5 ��923-���� �-�4�9��2���6/����$� ()*��55�-2�3� ��3�3 ��!'+� -3��* �3�-���+����-���9 -���������.� + ��3,��3 � �( ����55�-2�3-���,�3 ���� * � � �39 �� �+>�� ����� +�3���7� -�6���2� 3� �+>�� ����� * � �,� �-�� �+>�� ����� +�g�()*��55�-2�3-���<-3 ����$�� ��������55�-2�3� � ����?�� 0���@� @��@�� +�g�()*��55�-2�3-���6/� ���� ����?�� @���0� 0@?@0� +.g�* ��9�� �9 ���-��2��7��3-������ �������,�3 ��� ��.�.�� 0?@�0� �.��0� ���� (�-3�5 -2���+>�(�-3�5 -2���+>�(�-3�5 -2���+>�(�-3�5 -2���+>�����>>>>����������������������-2��g��0������-2�� 3 �<�g����( ���g��������+)��g��������!���g��0�����*/5 9,� g��������j-�2� 9�5 �3��g�������������� -2��2-�g�0����� � �� 4� ,��2���4�()*��55�-2�3� �� �<��-��+�6���0���7� �����5� �3-���3-,������4-����2�5�2-3/� �4�()*��55�-2�3� �<� �����0� � ������������� �� ���� � +�6���0���� 4� ,��2���4�()*��55�-2�3� ��3� ��%�����$��+����-���9 -���������������������.� �� �,�3� �� '�2�3-�� � �)�%� -3��������� !'+� -3��* �3�-�� !���� ()*��55�-2�3� �� 5� �3-���3-,��c � ����� ���0� ���0� ���0� �-����2�5�2-3/�c� �� ���� ������ ������ ����� e�����55�-2�3-���� 5� �3-���3-,��c � ����� .@��@� .��.�� .@�?�� �-����2�5�2-3/�c� �� ���� ������� ����@�� ������ #�,5� ���� +-,�� �7����7� � �����55�-2�3-���c�a���g���@0� � �� #��2�9 -��#��2�9 -��#��2�9 -��#��2�9 -������ ���� � �,�3<��/�� � 39�/��������������������.��-3�,�/�6��2��2�9����3 �3�2 �5 �<-3 �()*��55�-��� <-3 ����$�()*��55�-2�3� � �����6�93��@a�� -� � �/-����3 ���3 �3�<-3 ��� ��9�� �9 ����55�-2�3-��� �� ���$� ��7���5��� ()*� �55�-2�3� � 2��� �7�� 3-,�� ����@0a�� ���� ��6� � 2� 3� ���-� 3� 3 �� ()*� �55�-2�3-���6/� �����$3��� �� ��92���..a�9 ����7� �3 ��� ��9�� �9 ����55�-2�3-���-��2��7��3-����� ,�3 ���� + � �55�-2�3� � 9 �� � 7� /� -,5��� ���� �� /� ���� 3 9 � 3 �� �55�-2�3� � <-��� 6�� 5�59�� � �,���� 3 �� 4� ,� ���/� 6/� ��/��+ � �4� ��� 3 �� 3�2 �����/�,�/�6�� �2�,,������ � ��d3�� -��� ,� ����4� �9 -����3 ���55�-2�3� �-���� ��� 2������ ��� �� 4� ,��2���4�()*��55�-2�3� � ��4� ��2� ��4� ��2� ��4� ��2� ��4� ��2� ���� ���� ���$���������� ��-2���� �� 2 �$� 3-393����������$,5�23��4�'##�����()*���� -2��5 ��923-���-�� �,�� ���23��� � �� �� ���9��� �� �� 2 � ��7-�<� �5� 3�� �� -29�39 ��� �2���,-2 �%-7-���� �������� ��-2���� �� 2 �$� 3-393���*�8-59 ��55�������� ���$� ��������� ��-2���� �� 2 � $� 3-393���� ������ k�� 9�->�% ��� �# � l��������-�&� -�������� �������� ��-2���� �� 2 �$� 3-393���*�8-59 �������55��@�@��� e�b9���!������!�� )��e� �-���!��!����-� ����!����� �� ,���� ���.��� �7��9�3-��� �4� �-44� ��3� ,�3 �� � �4� 9 ��� �55�-2�3� � ���� <���� 2��3 ��� ,�� 9 � � 4� � ,�d-,-8-��� �� �� -2�� 5 ��923-7-3/���������� ��� ��������@���������� e�b9���!���!�����f� �6���!�����e� �-���;��;��)� ������!��)��e� �������.6��$,5 �7�,��3� �����7��9�3-����4����$�()*��55�-2�3� ���� -2�������$�3���#$*������0�������?��� $���$�����������9�����5� 3�����.������� $�3� ��3-�������������-2/��� �� 2 � $� 3-393�� �$���$��� f� -��3����%#��()���5����� )�7��3��"��;�������������)3��������??���%��5�5��2�,��3��4�9 ��� 95� �� ��9�� �-��3 �� 5���3��� -2���� -�2-5�� �����5 �23-2� ��"93 -��3�#/2�-���-���� ��2� / ����0��������.�� )�7��3��"��;������)�� ��>-��2�����%��*� 2-���)��)��% �����������; �� ���)�����# �7��������;�� )��������??����� ���,-2�5� 4� ,��2���4�9 ���6 -b9�33���55�-2�3� �-��3 �� 5���3��� -2��� "93 -��3�#/2�-���-���� ��2� / ���.�������.?������ f� �6�����!���!�����e�b9���!��$��e� �-������!��)��e� �-���������k���$�*93-�( ���5 �/��� i��3 � � >� i�5 ����-� �� 6�6� � l�� ������-� &� -���� �� ,� !�2 -�� /� ���� �� 3 � 7� 3� � �2� � ���-��� -��� %�5� 3,��3�� �������� � �� -29�39 ��� �� �� 2 � $� 3-393��� *�8-59 � ������ � � � � � � � � � � � � � � � bangladesh agron. j. 2016, 19(2): 51-60 yield response of soybean (glycine max l.) genotypes to water deficit stress afsana mimi1, m. a. mannan1*, q. a. khaliq1 and m. a. baset mia2 1department of agronomy, 2department of crop botany bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh. *corresponding author: mannanbsmrau@yahoo.com key words: soybean, water stress, seed yield abstract an experiment was carried out at research field of agronomy, department of bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur from december 2013 to april 2014. four soybean genotypes viz. i) g 00022 ii) galarsum iii) bari soybean-5 and iv) g 00197 were grown in the field to evaluate the effects of water deficit stress on dry matter accumulation and yield. plants were subjected to water stress that is irrigation was withdrawn at blooming stage (r1) and full pod (r4 stages up to maturity. dry matter accumulation, yield and yield components were reduced by the soil water deficit stress and reduction was higher at r1 stage than r4 stage of water stress. among the genotypes, g 00022 showed the highest tolerance, while g 00197 was highly susceptible in all the water stress conditions. it was found that higher water deficit stress tolerance in g 00022 was associated with higher accumulation of leaf, stem, root and total dry matter under water stress condition. introduction soybean (glycine max l.) is the world’s most important grain legume crop in terms of total production, consumption and international trade. the oil which is 20% of the seed is high in essential fatty acids and devoid of cholesterol and constitutes more than 50% of the world’s edible vegetable oil in trade (ogundipe and weingartner, 1992). it is an important grain legume because of its high protein (35%), and nitrogen fixing ability (17-127 kg n ha-1 year-1) (messina, 1997). soybean is inherently more stress tolerant (singh et al., 2003) than other legume crops but it still suffers considerable damage due to drought stresses in different regions where rainfall is scanty or irregular and irrigation facility is unavailable like north western region of bangladesh. water stress is an abnormal condition where there is a lack of sufficient water to meet the normal needs of agriculture which causes drought hazards ultimately. bangladesh is at higher risk from droughts and faces unpredictable water stress due to inadequate and uneven rainfall. so, selection of water deficit stress tolerant crop cultivar among the available genotypes and their introduction to water stressed area or drought prone areas may become a worthy effort to utilize these lands of bangladesh. low intake of proteins and fats results in malnutrition, and is therefore, soybean can be considered a functional food crop for the people of developing countries like bangladesh and might be a worthy effort to utilize drought prone north western regions of bangladesh to meet up the country’s food and nutritional deficits. so, the aim of the present study was to identify relatively water deficit stress tolerant soybean genotypes for drought prone areas of bangladesh. mailto:mannanbsmrau@yahoo.com 52 mimi et al. materials and methods the experiment was conducted in the agronomy field of bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur from december, 2013 to april, 2014. the soil is characterized by silty-clay with ph value of 6.5. four soybean genotypes g00022, galarsum, bari soybean 5 and g00197 were used in this experiment which was screen out from 50 genotypes at seedling stage water deficit stress condition in previous experiment. the plot was first opened by moldboard plough. subsequently, it was prepared by deep and cross ploughing and harrowing followed by laddering. the unit plot size was (1.5 m x 2.0 m). the manures and fertilizers were applied as recommended by mandal et al. (2011). cowdung and all other chemical fertilizer + 1/2 urea were applied as basal. rest of urea was applied at 25 days after sowing. during sowing, firstly seeds were treated with provex-200 @ 2.0 g kg-1 seed for an hour before sowing. the seeds were covered with pulverized soil just after sowing and gently pressed with hand and light watering was done in the line just to supply sufficient moisture need for quick germination. three different treatments were applied(i) control: irrigation plot, (ii) water deficit stress 1: irrigation was withdrawn at r1 (beginning flowering) stage up to maturity and (iii) water deficit stress 2: irrigation was withdrawn at r4 (full pod) stage up to maturity. the experiment was laid down in split plot design with 3 replications. the crop was protected from the attack of insect pests by spraying of darsban 20 ec @ 5.0 ml l-1 of water and disease was controlled by applying dithane m-45 @ 2.0 g l-1 of water at the base of the plants. at maturity, five plants from each plot were collected and sampled and data on dry weight of leaf, stem, root, total dry weight, as well as yield and yield contributing characters were recorded. seed yield was adjusted to 12% moisture content. grain yield was recorded on the basis of total harvested seeds plot-1 and was expressed the grain yield in t ha-1. the data recorded on different parameters were statistically analyzed with the help of mstat-c program and the difference between the treatments means were compared by lsd test (gomez and gomez, 1984). results and discussion leaf dry matter significant genotypic variation in leaf dry matter accumulation was noticed under water deficit stress conditions (figure 1). leaf dry weight was decreased due to water deficit stress in all the genotypes studied and decreasing rate was higher when plants were subjected to water stress at r1 stage than r4 stage. but in both stages of r1 and r4, g00022 maintained highest relative leaf dry weights which are 77.7 and 81.1%, respectively. at r4 stage under water deficit stress condition, highest relative leaf dry weight was found in genotype g00022 (81.1%) and it was lowest in g00197 (51.4%). compare to water stress at r4 stage, a significant reduction in leaf dry matter in r1 stage between genotypes was observed (fig. 1). compared to control plant a minimum reduction in leaf dry matter was recorded at r1 stage in g 00022 (22.3%), whereas the maximum reduction was recorded in g00197 (54.1%). water deficit stimulates leaf abscission as drought stress has been reported to induce production of ethylene in a variety of species (kacperska and kubacka-zebalska, 1989). though the resulting decrease in leaf area is one of the mechanisms of moderating water loss from the crop canopy and averting excessive drought induced injury to the plant; this may lead to a decrease in leaf dry matter production due to reduction in photosynthetically active leaf area (vurayai et al., 2011). the genotype g00022 through its capacity of minimum reduction in leaf dry matter actually maintained better photosynthetic tissue under water stress conditions. 53 yield response of soybean (glycine max l.) genotypes to water deficit stress fig. 1. relative leaf dry weight of four selected soybean genotypes as affected by water deficit stress stem dry matter water deficit stress significantly decreased stem dry matter accumulation in all the soybean genotypes at both r1 and r4 stages stress (fig. 2) and the reduction was higher at r1 stage. the different genotypes showed different relative values (compared to control) of stem dry mass under water deficit stress conditions. at r1 stage water stress g 00022 produced the highest (57.61%) stem dry mass at maturity, while g00197, bari soybean 5 and galarsum produced only 47.20, 38.31 and 35.58% stem dry matter, respectively (fig. 2). stem dry mass reduction was the lowest in g00022 among the genotypes. in addition to reduced node m-2, drought stress during the flowering period retards early ovary expansion because of reduced photosynthetic supply (liu et al., 2004). the period from 10 days before r1 to 10 days after r1 is the critical period. on the other hand, frederick et al. (2001) stated that drought stress treatment had no effect on branch number per m2 measured at flowering but had a large effect on the final number of branches formed. this disagreement may be due to the different environmental conditions and the different soybean cultivars used in the experiments. fig. 2. relative stem dry weight of four selected soybean genotypes as affected by water deficit stress 54 mimi et al. root dry matter root dry matter was also significantly reduced by water deficit stress at r1 and r4 stages in all soybean genotypes (fig. 3) and reduction was higher at r4 stage of water stress compared to r1 stage of water stress. the highest relative root dry matter (73.56%) was produced by genotype g 00022 and the lowest (40.11%) in g00197 at r4 stage of water stress. root growth of other genotypes under water deficit stress conditions was more than 50% at r1 stage of water stress (fig. 3). the reduction in root dry matter is probably due to reduction in dry matter of both tap root and adventitious root as a result of a reduction in root length and branching. the better root growth under water deficit condition can be considered as the capacity of the genotype g 00022 to combat the immediate adverse effect of water stress and presumably contributed to higher shoot growth under the stress conditions. silvius et al. (1977) found a decreased dry weight of roots and shoots in response to drought imposed during both vegetative and reproductive stages of soybean. fig. 3. relative root dry weight of four selected soybean genotypes as affected by water deficit stress total dry matter total dry matter production is decreased with increasing soil moisture deficits. both r1 and r4 stages of water deficit affected significantly the total dry matter production in all the soybean genotypes studied. total dry matter reduction due to water deficit stress was higher at r1 stage than that at r4 stage (fig. 4). de costa and shanmugathasan (2002) reported that maximum total biomass increased significantly with the number of stages irrigated, with irrigation during the vegetative stages having the highest positive effect and found that water stress significantly decreased the total dry matter production. lisar et al. (2012) reported that the impacts of water deficit stress in crop plants can reduce productivity by 50% in various parts of the world. water stress induced differences in total dry matter production among the genotypes were caused by the differences in the reduction of root, leaf and stem dry matter over their control. the dry matter reduction in moderately tolerant and moderately susceptible genotypes was in between this minimum and maximum range. the total dry matter in genotype g 00022 was less affected even at r1 stage water stress, which could be attributed to more efficient production of leaf, stem, and root dry matter. water stress generally reduced the growth of plant components resulting in lesser total dry weight (tdw). abo el-khier et al. (1994) found that water stress 55 yield response of soybean (glycine max l.) genotypes to water deficit stress decreased significantly plant height, number of leaves and branches, total leaf area and dry weight of shoots per plant of soybean cultivars. fig. 4. relative total dry weight of four selected soybean genotypes as affected by water deficit stress number of pod water deficit stress significantly reduced the number of pods plant-1 compared to that in control in all the four soybean genotypes studied. the reduction was small at r4 stage of water stress compared to that at r1 stage. the reduction in pods plant -1 at r4 stage ranged from 15% to 41%. in control treatment, bari soybean 5 produced the highest pods plant-1 (61.20). however, at r1 stage of water stress treatment bari soybean 5 produced only 50% pod of the control. the production of pods plant-1 at r1 stage of water stress reduced to a great extent and ranged from 22% in genotype g 00022 and 51% in bari soybean 5 (table 1). a similar result was obtained by ball et al. (2000). in a previous study, it was also reported that deficit irrigation at r2 stage reduced seed yield by 4%, while deficit irrigation at the r5 stage reduced seed yield by 28%, in comparison to the control (non-stressed) (karam et al., 2005). the highest relative number of pod in g 00022 might have attributed to a lower reduction in leaf dry matter as well as shoot dry matter of this genotype. water deficit at flowering stage has more effect on the yield through affecting the pod number decrease. water stress reduced number of pods plant-1 which would reduce the yield sharply. number of seed water deficit stress also reduced the average number of seed pod-1 significantly in all the soybean genotypes studied (table 1). the number of seeds pod-1 was less affected by water deficit at r4 stage in all the genotypes. the maximum relative seed number pod-1 was produced by the genotype g00022 (94%), followed by galarsum (91%) and bari soybean 5 (76%) and the lowest by g00197 (74%) at r1 stage. the highest seed number pod-1 in genotype g00022 was probably is due to the lowest reduction in pollen fertility due to drought stress as reported by omae et al. (2005). withdrawing of irrigation at r1 (omit irrigation at the onset of flowering stage) had the lowest one. 56 mimi et al. table 1. number of pod plant-1 and number of seed pod-1 of four selected soybean genotypes genotypes as affected by water deficit stress genotypes number of pods plant-1 number of seeds pod-1 treatments treatments control water stress at r1 stage water stress at r4 stage control water stress at r1 stage water stress at r4 stage g00022 23.733 18.600 (78.37%) 20.333 (85.67%) 1.867 1.750 (93.73%) 1.807 (96.79%) galarsum 53.267 31.400 (58.95%) 39.667 (74.74%) 1.730 1.583 (91.50%) 1.633 (94.39%) bari soybean 5 61.200 30.333 (49.56%) 36.133 (59.04%) 1.997 1.523 (76.26%) 1.663 (83.27%) g 00197 37.933 27.533 (72.58%) 29.867 (78.74%) 1.897 1.407 (74.17%) 1.537 (81.02%) lsd (0.05) 15.90 0.23 cv (%) 27.13 7.93 values in the parenthesis per cent of control 100seed weight exercising water deficit stress in grain– filling stage had a high effect on 100– seed weight plant-1, resulting decrease in this yield component. shortening of grain–filling period due to water stress and decrease of transferring assimilates in to grains due to water stress as two major reasons for reduction of soybean grain weight. water stress imposed on soybeans throughout the growing stages reduces vegetative growth and affects flowering and yield. seed weight decreased significantly at r4 stage water stress, which further decreased at r1 stage water stress (table 2). enormous variation in 100seed weight was also existed among genotypes. at r1 stage drought, 100 seed weight ranged from 3.63 g to 10.58 g, whereas at r4 stage drought that was from 3.93 g to 12.50 g. relative grain weight was the highest in g00022 (83 %), followed by galarsum (67%) and bari soybean 5 (45%), and it was the lowest in genotype g 00197 (43%) at r1 stage water stress. a remarkable reduction in the size of seeds was observed at r4 stage water stress in all the genotypes. in genotype g00022, relative seed weight was higher with compared to other genotypes which indicated that this genotype was more capable to partition more dry matter into the seeds than that of other genotypes, especially at water deficit stress. water deficit stress during reproductive development often decreases the seed size in soybean due to a shortening in the length of the seed filling period, rather than reduced seed growth rate reported by meckel et. al. (1984). grain yield grain yield was reduced by water deficit conditions in all the soybean genotypes studied and the decreasing rate was higher in r1 stage than r4 stage. highest yield was found in g00022 (65%) and lowest in g00197 (39%) at r1 stage. g00022 showed also highest yield at r4 stage (76%) and lowest in g00197 (58%). grain yield of different genotypes ranged from 1.65 to 3.09 t ha-1 under normal conditions and that from 0.64 to 1.76 and 0.96 to 2.13 t ha-1 under r1 and r4 stage water stress conditions, respectively (table 2). the highest relative seed yield was found in genotype g00022 at both the water deficit stress stages and the lowest were in g00197. the highest relative pod number plant-1 and individual seed weight in genotype g00022 mostly contributed to the highest relative seed yield of this 57 yield response of soybean (glycine max l.) genotypes to water deficit stress genotype. higher yield in tolerant genotype g00022 resulted with increases in the number of pods, higher rate of photosynthesis under water stress (palta et al., 2010). the higher number pods in tolerant cultivars was probably due to greater availability of the source to the reproductive sinks. quick recovery of photosynthesis and leaf growth in tolerant genotypes might also have resulted in small reduction of seed yield. there are significant differences in the tolerance of plants to drought stress depending upon intensity and duration of stress, plant species and the stage of development (sing et al., 2012). water stress causes a series of physiological, biochemical and morphological responses of crops, which finally results in low yield of green gram (malik et al., 2006). table 2. 100seed weight and seed yield of four selected soybean genotypes as affected by water deficit stress genotypes 100seed weight (g) seed yield (t ha-1) control water stress at r1 stage water stress at r4 stage control water stress at r1 stage water stress at r4 stage g00022 12.633 10.533 (83.38%) 12.400 (98.16%) 2.240 1.460 (65.18%) 1.707 (76.21%) galarsum 9.967 6.700 (67.29%) 9.167 (91.97%) 3.097 1.761 (56.86%) 2.056 (66.39%) bari soybean-5 12.233 5.500 (44.96%) 5.867 (47.96%) 3.022 1.764 (58.37%) 2.135 (70.65%) g 00197 7.867 3.367 (42.80%) 3.933 (49.99%) 1.654 0.648 (39.18%) 0.966 (58.40%) lsd (0.05) 1.62 0.18 cv (%) 11.13 18.51 values in the parenthesis per cent of control harvest index a significant genotypic variation in harvest index was noticed under water deficit stress conditions (fig. 1). harvest index was decreased due to water stress in all the genotypes studied and decreasing rate was higher when plants were subjected to water stress at r1 stage than r4 stage. at r1 stage water stress condition, highest relative harvest index was found in genotype g00022 (59%) and it was lowest in g00197 (48%). compare to water stress at r4 stage, a significant reduction in harvest index in r1 stage among genotypes was observed. according to kobraei et al. (2011) the relationship between grain yield and components yield (number of pod, number of grain pod-1 and plant-1) is positively and significant, therefore, decreasing these components may be reason for reducing grain yield and biological yield. this result is agreement with the results of daneshian et al. (2010) and kobraei et al. (2011) about the soybean responses to drought stress in terms of these traits. compare to well water condition; water stress caused reduction in harvest index by 12.7% in wheat genotypes as described by bayoumi et al. (2008). austin (1994) suggested that high harvest index may be due to improved tolerance to drought by making the plants much shorter along with enhancing the supply of nutrients to developing grains. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3656181/#cr41 58 mimi et al. fig. 5. relative harvest index of four selected soybean genotypes as affected by water deficit stress conclusions from the above findings it may be concluded that genotypic variability was found in adaptation of soybean plant to water stress. water stress affects adversely on dry matter accumulation and yield of soybean genotypes and the growth reduction was larger at r1 (blooming) stage drought compared to r4 (pod filling) stage drought. genotype g 00022 showed a higher water deficit stress tolerance while g 00197 was susceptible genotype in terms of both dry weight and yield performance references abo el-khier, m. s., s. a. kandil and b. b. mekki. 1994. physiological response of two cultivars grown under water stress conditions as affected by ccc treatment. egypt. j. physiol. sci. 81(1): 179 -200. austin, r. b. 1994. plant breeding opportunities. in: physiology and determination of crop yield. madison, usa: am. soc. agron. pp. 567-586. ball, r. a., l. c. purcell and e. d. vories. 2000. short-season soybean yield compensation in response to population and water regime. crop sci. 40: 1070 1078. bayoumi, t. y., m. h. eid and e.m. metwali. 2008. application of physiological and biochemical indices as a screening technique for drought tolerance in wheat genotypes. african j. biotech. 7:2341-2352. daneshian, j., p. jonoubi and d. tari-barari. 2010. investigation of water deficit stress on agronomical traits of soybean cultivars in temperature climate. int. j. agril. biol. sci. 1(2):75-82. de costa, w. a. j. m. and k. n. shanmugathasan. 2002. physiology of yield determination of soybean (glycine max l. merr.) under different irrigation regimes in the sub-humid zone of sri lanka. field crops res. 75(1): 23-35. 59 yield response of soybean (glycine max l.) genotypes to water deficit stress frederick, j. r., c. r. camp and p. j. bauer. 2001. drought-stress effects on branch and main stem seed yield and yield components of determinate soybean. crop sci. 41: 759-763. gomez, a. a. and a. a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. pp. 20-2015. kacperska, a. and m. kubacka-zebalska. 1989. formation of stress ethylene depends both on acc synthesis and on the activity of free radical generating system. physiol. plant. 77: 231-237. karam, f., r. masaad, t. sfeir, o. mounzer and y. rouphael. 2005. evapotranspiration and seed yield of field grown soybean under deficit irrigation conditions. agric. water manag.75: 226-244. kobraei, s., a. etminan, r. mohammadi and s. kobraei. 2011. effects of drought stress on yield and yield components of soybean. ann. biol. res. 2(5): 504-509. lisar, s. y. s., r. motafakkerazad, m. m. hossain and i. m. m. rahman. 2012. water stress in plants: causes, effects and responses. in: rahman, i. m. m. and hasegawa, h. water stress, in tech, croatia. pp. 1-14. liu, f., c. r. jensen and m. n. andersen. 2004. drought stress effect on carbohydrate concentration in soybean leaves and pods during early reproductive development: its implication in altering pod set. field crops res. 86: 1-13. malik, a., f. hassan, a. waheed, g. qadir and r. asghar. 2006. interactive effects of irrigation and phosphorus on green gram (vigna radiata l.). pak. j. bot. 38 (4): 1119-1126. mandal, m. r. i., m. s. islam, m. a. j. bhuiya, m. m. rahman and m. s. alam. 2011. krishi projukti hatboi (handbook on agro-technology). 5th edition. bangladesh agricultural research institute, gazipur-1706, bangladesh. meckel, l., d. b. egli, r. e. phillips, d. radcliffe and j. e. leggett. 1984. effect of moisture stress on seed growth in soybean. agron. j. 76: 647-650. messina, m. 1997. soy foods: their role in disease prevention and treatment. in liu, k. (ed). soybeans: chemistry, technology and utilization. chapman and hall, new york, pp. 442-466. ogundipe, h. o. and k. weingartner, 1992. effect of the addition of soybean on the nutritional status of selected traditional nigerian foods. tropic. oilseeds j. 1: 6773. omae, h., a. kumar, y. egawa, k. kshiwaba and m. shono. 2005. genotypic differences in plant water status and relationship with reproductive responses in snapbean (phaseolus vulgaris l.) during water stress. jpn. j. trop. agric. 49: 1-7. palta, j. a., a. ganjeali, n. c. turner and k. h. m. siddique. 2010. effects of transient subsurface waterlogging on root growth, plant biomass and yield of chickpea. agric. water manag. 97: 1469-1476. silvius, j. e., r. r. johnson and d. b. peters. 1977. effects of water stress on carbon assimilation and distribution in soybean plants at different stages of development. crop sci. 17: 713-816. singh, b. b., p. hartmann, c. fatokun, m. tamo, s. tarawali and r. ortiz. 2003. recent progress on cowpea improvement. chron. hortic. 43: 8-12. singh, s., a. k. gupta and n. kaur. 2012. differential responses of antioxidative defence system to long-term field drought in wheat (triticum aestivum l.) genotypes differing in drought tolerance. j. agron. crop sci. 198(3): 185-195. 60 mimi et al. vurayai, r., v. emongor and b. moseki. 2011. effect of water stress imposed at different growth and development stages on morphological traits and yield of bambara groundnuts (vigna subterranean l. verdc). am. j. plant physiol. 6(1): 17-27. bangladesh agron. j. 2015, 18(1): 81-88 salicylic acid and gibberelic acid ameliorates the adverse effects of salinity on chickpea m. i. hossain1, m. a. mannan2* and m. a. karim3 1assistant director, badc, bangladesh; 2 &3 department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh. *corresponding author: mannanbsmrau@yahoo.com key words: salicylic acid, gibberelic acid, ameliorates adverse effects, salinity and chickpea abstract a pot experiment was carried out under semi-controlled environmental condition in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh during december 2012 through march 2013 aiming to alleviate the salinity stress effects on chickpea using salicylic acid (sa) and gibberelic acid (ga3). chickpea variety bari chola-5 was used in the experiment. salt solution was prepared by adding tap water in sea water to make 5, 7.5 and 10 ds m-1 salinity level. plants were irrigated with 5, 7.5 and 10 dsm-1 concentrations of saline water from 14th days after sowing (das) to maturity (100 das) and control plants were irrigated with tap water. different concentration of sa (200 ppm and 400 ppm) and ga3 (10 ppm and 20 ppm) were applied as foliar spray once in a week from 20 das to flowering stage. the data for chlorophyll content in leaf and water relation traits such as relative water content (rwc) and water retention capacity (wrc) were measured 7 days after foliar spray of plant growth regulators at flowering stage. total dry weight (root+shoot), yield and yield contributing characters were measured at maturity. results indicated that salinity decreased total dry weight, chlorophyll content, relative water content, water retention capacity and yield of chickpea. foliar application of sa and ga3 at different doses under different salinity conditions had the positive effects related to mitigation of salinity stress effect but low concentration i.e., sa and ga3 @ 200 ppm and 10 ppm, respectively were found to alleviate the adverse effects significantly on the above parameters at low salinity condition (5 dsm-1). introduction the reduction in plant growth exposed to saline environments could be due to either the effects of specific ions on metabolism or adverse water relations (kaya et al., 2009). different strategies are being employed to maximize plant growth under saline conditions. one of them is to produce salt tolerant genotypes of different crops. attempts to improve tolerance to salinity through conventional plant breeding methods are time consuming, laborious and dependent on existing genetic variability. an alternative approach for coping with salinity could, therefore, be an exogenous application of growth regulators which diminish salinity effect in plant to a tolerable level. plant growth regulators like salicylic acid (sa) and gibberelic acid (ga3) are recognized endogenous regulator of plant metabolism, which mainly involved in biotic and abiotic stress (aydin and nalbantoglu, 2011). exogenous sa could regulate the activities of antioxidant enzymes and increase plant tolerance to abiotic stresses (he et al., 2002; erasalan et al., 2007). gibberelic acid regulates growth and development to the plants and to be helpful in enhancing growth of development of wheat and rice under saline conditions (schwechheimer, 2008). maggio et al. (2010) reported that ga3 treatment in tomato reduced stomatal resistance and enhanced plant water use at low salinity. mailto:mannanbsmrau@yahoo.com 82 hossain et al. chickpea (cicer arietinum l.) is an annual grain legume or “pulse crop” that is known as „chola‟ in bangladesh is mainly used for human consumption as well as for animal feeds. chickpea seeds contain 21% protein, 5.6% fat, 60% carbohydrate, and are rich in minerals and vitamins. chickpea is a salt-sensitive crop, and yields are seriously reduced by salinity (manchanda and sharma, 1990). the information regarding the action of salicylic acid and gibberelic acid in enhancing salt tolerance and growth of chickpea is not enough for making any concrete recommendation to the end-users. a very limited works have been carried out regarding the use of growth regulators like sa and ga3 on chickpea varieties in relation to salinity tolerance in bangladesh. therefore, the present study was undertaken to evaluate the effects of sa and ga3 to enhance salinity tolerance of chickpea. materials and methods a pot experiment was conducted under semi-controlled environmental condition in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur during from december 2012 to march 2013. the soil used in the experiment was clay loam in texture with neutral in nature and poor fertility status. chickpea variety bari chola 5 was used in the experiment. ten seeds were sown in each plastic pots of 24 cm (diameter) x 30 cm (height) in size filled with soil inside plastic house under natural light. compost (25% of the soil volume) and 0.27-0.28-0.20 g of urea, triple super phosphate and muriate of potash per pot for supplying n, p2o5 and k2o, respectively were incorporated uniformly into the soil. the compost was made mostly from cow dung which contained 0.8% n, 0.6% p2o5 and 1.0% k2o on dry weight basis. after seedling establishment, five uniform and healthy plants were allowed to grow in each pot. weeding and pest control measures were taken for proper growth of plants. salt solution was prepared by adding tap water in sea water to make 5, 7.5 and 10 dsm-1 salinity level. plants were irrigated with these 5, 7.5 and 10 dsm-1 concentrates saline water from 14th days after sowing (das) to maturity (100 das) and control plants were irrigated with tap water. different concentration of sa and ga3 were applied as foliar spray once in a week from 20 das to flowering stage. the treatments of the experiment were: i. control (non saline condition) ii. 5 dsm-1 salinity iii. 7.5 dsm-1salinity iv. 10 dsm-1 salinity v. 5 dsm-1 salinity + 200 ppm sa vi. 7.5 dsm-1 salinity + 200 ppm sa vii. 10 dsm-1 salinity + 200 ppm sa viii. 5 dsm-1 salinity + 400 ppm sa ix. 7.5 dsm-1 salinity + 400 ppm sa x. 10 dsm-1 salinity + 400 ppm sa xi. 5 dsm-1 salinity + 10 ppm ga3 xii. 7.5 dsm-1 salinity + 10 ppm ga3 xiii. 10 dsm-1 salinity + 10 ppm ga3 xiv. 5 dsm-1 salinity + 20 ppm ga3 xv. 7.5 dsm-1 salinity + 20 ppm ga3 and xvi. 10 ds m-1 salinity + 20 ppm ga3. the data for chlorophyll content and water relation traits in leaf such as relative water content (rwc) and water retention capacity (wrc) were recorded 7 days after foliar spray of sa and ga3 at flowering stage. chlorophyll content was estimated from the fully expanded uppermost leaf samples using the method described by witham et al. (1986). to measure the relative water content (rwc), fresh weight of the collected leaves sample was measured immediately. thereafter, the leaves were immersed in distilled water for 24 hours at room temperature in the dark. these leaves were weighed to record the turgid (saturated) weight after excess water was removed, by gently wiping the leaves with a paper towel. the leaves were then dried in an oven for 48 hours at 72 0c to determine their dry weight. the values of the fresh, turgid and dry weights of the leaves were used to calculate rwc = (fw– dw) / (tw-dw) x 100, where, fw = fresh weight of the leaf, dw = dry weight of the leaf, tw = turgid weight of the leaf. water retention capacity is the ratio of the turgid weight and dry weight of a leaf. after the harvest both treated and controlled plants were segmented into 83 salicylic acid and gibberelic acid of salinity on chickpea different components (root, stem, leaf). the segmented parts were then oven dried for 72 hours and the dry weights were recorded. total dry weight of both treated and control plant were estimated by summing up the dry weight of root, stem and leaf. pods were collected from the plant and data were recorded on number of pod plant-1, number of seed pod-1, 100 seed weight and seed yield plant-1 in case of both treated as well as control plants in each pot. the data recorded on different parameters were statistically analyzed with the help of mstat-c program. means were compared to adjust the difference in plant performance under growth regulators treatments experiencing both salinity and control conditions by least significant different test (gomez and gomez, 1984). results and discussion total dry weight dry matter accumulation was decreased significantly with an increasing salinity levels. it was found that control plant produced highest total dry matter (17.94 g plant-1) and under 5 dsm-1 saline condition it was (14.68 g plant-1). minimum total dry weight was found at 10 dsm-1 saline condition (12.48 g plant-1), which was only 69% of the control (fig. 1). total dry weight increased when foliage was sprayed with sa and ga3 at different rates under salinity stress. 16.00 g plant-1 dry matter was obtained when plant was sprayed with sa @ 200 ppm, followed by 15.40 g plant-1 when plant was sprayed with ga3 @ 10 ppm under 5 dsm-1 salt treated plants. when plant was sprayed with sa @ 400 ppm and ga3 @ 20 ppm total dry matter plant-1 was found 14.8g and 14.49 g, respectively under the same (5 dsm-1) salinity condition. at 10 dsm-1 saline condition when plant was sprayed with sa @ 200 ppm and ga3 @ 10 ppm, dry matter production was 12.79 g and 13.29 g plant-1, respectively. on the other hand, when plant was sprayed with sa @ 400 ppm and ga3 @ 20 ppm dry matter production was 12.5 g and 12.91 g plant-1, respectively under the same (10 dsm-1) salinity stress. lower doses of sa and ga3 show remarkable effect on dry matter production under saline condition. simillar results also reported by yildirim et al. (2008) and hussien et al. (2007) who reported that exogenous application of sa ameliorated the negative effect of salt stress on dry weight of plants. our results are in agreement with the findings of ashraf et al. (2002) who that ga3 in salt stressed plants showed an increased photosynthetic capacitya vital factor for higher dry matter synthesis. ** * * 84 hossain et al. relative water content relative water content was low under saline conditions compared to control (fig. 2). control plant maintained highest rwc (85%). under saline condition, rwc% decreased and decreasing rate was higher with increasing salinity levels. at 5, 7.5 and 10 dsm-1 salinity conditions rwc were 80%, 76% and 68%, respectively. however, foliar application of sa and ga3 increased the rwc under different salinity conditions. when plant was sprayed with sa @ 200 ppm and ga3 @ 10 ppm rwc was 83% and 80%, respectively under 5 dsm-1 salinity condition. at 10 dsm-1 saline condition when plant was sprayed with sa @ 200 ppm and ga3 @ 10 ppm, rwc was 69% and 68%, respectively. on the other hand, when plant was sprayed with sa @ 400 ppm and ga3 @ 20 ppm rwc was 66 and 67%, respectively under the same salinity (10 dsm-1) stress. so rwc increasing rate was lower when plant was sprayed with higher doses of sa and ga3. the results are in close conformity of the fact that sa potentially generates a wide array of metabolic responses in plants and also affects plant water relations (hayat et al., 2010). water retention capacity water retention capacity is the ratio of the turgid weight and dry weight of a tissue. control plants (non saline condition) maintained the maximum wrc (about 7.0) than the saline treated plants and it was gradually decreased with the increased salinity level. under 10 ds/m salinity level it was 3.8. sa and ga3 enhance the salinity tolerance and increase the water retention capacity (fig. 3) and increasing rate was higher when plant was sprayed with 200 ppm sa and 10 ppm ga3 under 5 ds/m saline condition. ahmad et al. (2009) reported in their study that application of ga3 counteracted the adverse effects of nacl salinity on relative water content. ** * 85 salicylic acid and gibberelic acid of salinity on chickpea chlorophyll content chlorophyll in chickpea leaf decreased as the salinity level increased and maximum reduction was observed at the highest salinity level (10dsm-1). maximum chlorophyll content was recorded in plants grown under normal condition (fig.4). the foliar application of sa and ga3 increased the chlorophyll level in salt treated plant but increasing rate was higher when plant was sprayed with lower doses of sa and ga3. the superior effects on chlorophyll content were recorded under the treatments of sa and ga3 at concentration of 200 ppm and 10 ppm, respectively under lower salinity level (5 dsm-1). ghai et al. (2002) reported that the application of sa to the foliage of brassica napus improved the chlorophyll content under salinity stress. an increase in chlorophyll content with ga3 was also reported earlier by hayat et al. (2001). ** ** * * * * * 86 hossain et al. yield and yield contributing characters number of pod pod number decreased with increasing salinity level. lowest pod number (16.08) was found in plant irrigated with 10 dsm−1, which was 47% of the control plant (table 1). however, pod number increased when plant was sprayed with sa and ga3 under saline condition. when plant was sprayed with sa @ 200 ppm under 5, 7.5 and 10 dsm-1 saline water treated plant; number of pod was produced by chickpea 31, 21 and 16 which were 93%, 63% and 49%, respectively compared to control. but it was 80%, 67% and 53%, respectively when plant was sprayed with sa @ 400 ppm. on the other hand, when plant was sprayed with ga3 @ 10 ppm under 5, 7.5 and 10 dsm-1 saline water treated plant; number of pods per plant was produced by chickpea 30, 22 and 19 which were 89%, 66% and 55%, respectively of the control. but it was 81%, 64% and 50%, respectively when plant was sprayed with ga3 @ 20 ppm. it is revealed that high concentration of sa and ga3 did not show significant ameliorative effect of salinity stress in chickpea in respect of number of pod. 100-seed weight the highest seed weight per plant was found in non saline condition (24.88 g). seed weight decreased when plant was irrigated with sea water and decreasing rate was higher with increasing salinity level. lowest weight obtained 3.47 g, which was 14% of the control when plant was irrigated with 10 dsm-1 saline water (table 1). however, seed weight increased when plant was sprayed with sa and ga3 under saline condition. when foliage was sprayed with sa @ 200 ppm under 5, 7.5 and 10 dsm-1 saline water irrigated plant; 100 seed weight was produced by chickpea 18.76 g, 4.71 g and 2.52 g which were 75%, 19% and 10%, respectively compared to control. but it was 69%, 22% and 14%, respectively when plant was sprayed with sa @ 400 ppm. on the other hand, when plant was sprayed with ga3 @ 10 ppm under 5, 7.5 and 10 dsm-1 saline water irrigated plant; 100 seed weight was 17.30 g, 5.61 g and 3.63 g which were 69%, 21% and 18%, respectively of the control. but it was 73%, 22% and 14%, respectively when plant was sprayed with ga3 @ 20 ppm. it is clear that high concentration of sa and ga3 did not show significant ameliorative effect of salinity stress in chickpea in relation to seed weight. seed yield the highest amount of seed yield per plant was obtained from the control plants (6.34 g). seed yield decreased when plant was irrigated with sea water and decreasing rate was higher with increasing salinity level. lowest yield obtained 1.37 g, which was 21% of the control when plant was irrigated with 10 dsm-1 saline water (table 1). however, seed yield was significantly increased when plant was sprayed with sa and ga3 under saline condition. when foliage was sprayed with sa @ 200 ppm under 5, 7.5 and 10 dsm-1 saline water irrigated plant; seed yield was produced by chickpea 5.82 g, 2.23 g and 1.87 g which were 92%, 35% and 20%, respectively compared to control. but it was 81%, 37% and 18%, respectively when plant was sprayed with sa @ 400 ppm. on the other hand, when plant was sprayed with ga3 @ 10 ppm under 5, 7.5 and 10 dsm-1 saline water irrigated plant; seed yield per plant was 5.65 g, 2.0 g and 1.28 g which were 89%, 31% and 20%, respectively of the control. but it was 89%, 25% and 19%, respectively when plant was sprayed with ga3 @ 20 ppm. it could be stated that the beneficial effect of sa on improving yield may be due to the translocation of more photo assimilates to the seeds. these results may be due to the role of salicylic acid in enhancing some physiological and biochemical aspects under stressful conditions (maity and bera, 2009). 87 salicylic acid and gibberelic acid of salinity on chickpea table 1. effects of plant growth regulators on seed yield and yield contributing characters of chickpea under salinity stress treatments number of pod/plant 100-seed weight (g) seed yield/ plant (g) control (non saline) 33.73 24.88 6.34 5 dsm-1 salinity 26.99 (80.01)* 16.93 (68.04) 4.75 (74.92) 7.5 dsm-1 salinity 21.50 (63.74) 5.25 (21.10) 2.34 (36.90) 10 dsm-1 salinity 16.08 (47.67) 3.47 (13.94) 1.37 (21.60) 5 dsm-1 salinity+200 ppm sa 31.63 (93.77) 18.76 (75.40) 5.82 (91.79) 7.5 dsm-1 salinity+200 ppm sa 21.47 (63.65) 4.71 (18.93) 2.23 (35.17) 10 dsm-1 salinity+200 ppm sa 16.40 (48.61) 2.52 (10.12) 1.27 (20.03) 5 dsm-1 salinity+400 ppm sa 27.21 (80.67) 17.30 (69.53) 5.17 (81.54) 7.5 dsm-1 salinity+400 ppm sa 22.88 (67.83) 5.61 (22.54) 2.38 (37.53) 10 dsm-1 salinity+400 ppm sa 17.92 (53.12) 3.63 (14.59) 1.14 (17.98) 5 dsm-1 salinity+10 ppm ga3 30.00 (88.94) 17.09 (68.68) 5.65 (89.11) 7.5 dsm-1 salinity+10 ppm ga3 22.46 (66.58) 5.30 (21.30) 2.00 (31.54) 10 dsm-1 salinity+10 ppm ga3 19.77 (58.61) 4.42 (17.76) 1.28 (20.18) 5 dsm-1 salinity+20 ppm ga3 27.46 (81.41) 18.13 (72.86) 5.03 (79.33) 7.5 dsm-1 salinity+20 ppm ga3 21.78 (64.57) 5.62 (22.58) 1.62 (25.55) 10 dsm-1 salinity+20 ppm ga3 16.90 (50.10) 3.60 (14.46) 1.20 (18.92) lsd (0.01) 6.75 2.81 0.75 cv% 14.00 13.73 11.65 *per cent of control conclusion from the results it was concluded that salinity decreased dry matter production, chlorophyll content, water relation traits and yield of chickpea. foliar application of sa and ga3 @ 200 ppm and 10ppm, respectively alleviated the adverse effects of salinity at low level (5 dsm-1). sa and ga3 at high concentration did not show appreciable performance to alleviate the adverse effect of salinity at high saline conditions. therefore, nacl induced reduction in the plant growth and yield of chickpea could be mitigated by exogenous application of plant growth regulators as sa and ga3 at low concentration under low salinity stress. acknowledgement we are grateful to the research management committee, bangabandhu sheikh mujibur rahman agricultural university, bangladesh for funding the study. 88 hossain et al. references ahmad, p., c. a. jelell, m. m. azooz, and g. nabi. 2009. generation of ros and non enzymatic anti-oxidants during abiotic stress in plants. bot. res. int. 2: 11-20. ashraf, m. y., k. akhtar, g. sarwar and m. ashraf. 2002. evaluation of arid and semi-arid ecotypes of guar (cyamopsis tetragonoloba l.) for salinity (nacl) tolerance. arid environ. 52: 473-482. aydin, b. and b. nalbantoglu. 2011. effects of cold and salicylic acid treatments on nitrate reductase activity in spinach leaves. turk. j. biol. 35: 443-448. eraslan, f., a. gunes, a. inal, m. alpaslan, e. g. bagci, n. cicek. 2007. salicylic acid induced changes on some physiological parameters symptomatic for oxidative stress and mineral nutrition on maize (zea mays l.) grown under salinity. j. plant physiol. 164: 728-736. ghai, n., r. c. setia and n. setia. 2002. effects of peclobutrazol and salicylic acid on chlorophyll content, hill activity and yield components in brassica napus. phytomorphology. 52: 82-87. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agriculture research, 2nded, new york: john wiley. hayat, q., s. hayat, m. irfan and a. ahmad. 2010. effect of exogenous salicylic acid under changing environment: a review. environ. exp. bot. 68(1): 14-25. hayat, s., a. ahmad and m. mobin. 2001. carbonic anhydrase, photosynthesis and seed yield in mustard plants treated with phytohormones. photosynthetica. 39: 111-114. he y. l., y. l. liu, q. chen and a. h. bian. 2002. thermo tolerance related to antioxidation induced by salicylic acid and heat hardening in tall fescue seedlings. j. plant physiol. mol. biol. 28: 89-95. hussein, m., m. l. k. balbaa and m. s. gaballah. 2007. salicylic acid and salinity effects on growth of maize plants. res. j. agri. biol. sci. 3: 321-328. kaya, c., a. l. tuna and i. yokas. 2009. the role of plant hormones in plants under salinity stress. springer, new york. p. 145. maggio, a., n. barbieri, d. raimondi and s. pascale. 2010. contrasting effects of ga3 treatments on tomato plants exposed to increasing salinity. j. plant growth regul. 29: 63-70. maity, u. and a. k. bera. 2009. effect of exogenous application of brassinolide and salicylic acid on certain physiological and biochemical aspects of gram green (vigna radiatal. wilcrek). indian j. agric. res. 43: 194-199. manchanda, h. r., and s. k. sharma.1990. tolerance of chloride and sulfate salinity in chickpea (cicer arietinum). j. agric. sci. 113: 407-410. schwechheimer, c. 2008. understanding gibberellic acid signaling – are we there yet? curr. opin. plant biol. 11:9–15. witham, h., d. f. blades and r. h. devin.1986. exercise in plant physiology (2nd edition). pws publishers, boston, usa. pp. 128-131. yildirim, e., m. turanand i. guvenc. 2008. effect of foliar salicylic acid applications on growth, chlorophyll and mineral content of cucumber (cucumis sativus l.) grown under salt stress. j. plant nutr. 31: 593-612. microsoft word 15. baj-306_revised bangladesh agron. j. 2017, 21(1): 131-141 effect of seed moisture content and storage container on seed viability and vigour of soybean m. r. ali1, m. m. rahman2, m. a. wadud2, a. h. f. fahim1 and m. s. nahar1 1spices research centre, bari, shibganj, bogura 2department of agronomy, bangladesh agricultural university, mymensingh 1spices research centre, bari, shibganj, bogura *corresponding author, e-mail: rajabag68@yahoo.com (received: 13 august 2018, accepted: 16 september 2018) keywords: soybean, seed moisture, storage container, viability, vigour abstract soybean (glycine max) seed loses its viability in the storage which causes shortage in supply of quality seed and consequently hinders the expansion of soybean cultivation in bangladesh.losses of seed viability of soybean (glycine max) in traditional storage is very common in the tropical environment. an experiment was conducted at the seed laboratory, regional agricultural research station, bangladesh agricultural research institute (bari), jamalpur in 2011 and 2012 to find out the effect of seed moisture content and types of storage container on soybean seed germination and seedling vigour. in 2011, soybean seed having 94% initial germination was stored at 8, 10 and 12% moisture levels but in 2012 seeds having 96% initial germination was stored at 6, 8, 10 and 12% initial moisture levels in four different types of storage containers viz., polythene bag, plastic pot, tin can and glass jar. weredays after storage ().the experiment was arranged in a factorial completely randomized design with three replications. in 2011, high germination of soybean seed (77-85%) was retained at 200 das for those stored at 8% initial seed moisture content (smc) in any of the containers. germination index and seedling dry matter decreased with increased initial seed moisture content irrespective of storage containers used. tin preserved higher seed moisture contents of 9.93, 11.71 and 14.15% for seed stored at 8%, 10% and 12% initial seed moisture content, respectively. in 2012, 80-94% seed germination was retained at 200 das for those stored at 6% initial smc in any of the containers. the germination declined to a range between 75.0 and 91.3% within 200 das at 8% initial smc while those stored at 12% smc showed rapid germination loss and the value showed down to between 9.3 and 22.0%. vigour index and seedling dry matter decreased with increased initial seed moisture content irrespective of storage containers used. tin also seeds stored in tin container showed the higher final seed moisture contents irrespective of initial seed moisture content. introduction seed is a living entry and is subjected to various stresses which affect the quality. in storage, the viability and vigour of the seeds not only vary from genera to genera and variety to variety, but it is also regulated by many physico-chemical factors like moisture content, atmospheric relative humidity, temperature, initial seed quality, physical and chemical composition of seed, gaseous exchange, storage structure, packaging materials, etc. in order to prevent the quantitative and qualitative losses due to several biotic and abiotic factors during storage, several methods are being adopted, such as seed treatment with suitable chemicals or plant products and storing in safe containers, besides sanitation of the storage place. to combat these factors effectively, 132 ali et al. storing the seeds in vapour proof containers like polythene bag, aluminum foils, tins or any sealed containers is found to be more useful in maintaining the desired quality of seeds for longer period, unlike those stored in moisture pervious containers like cloth bag and gunny bag. arunnandhy and senanayaka (1991) reported that the soybean seeds can be kept with high germination and vigour for more than one year when stored in sealed containers. storage containers or packaging materials are considered as one of the most important factors influencing longevity of seeds in storage. many factors determine the longevity of seeds during storage. these includes seed moisture content, temperature, relative humidity, initial viability, stage of maturity at harvest, storage gas and initial moisture content of seed entering into storage (tatipata, 2009). the farmers depend on their previous harvest for seeds and accordingly they preserve some portion of their harvest by indigenous methods. generally low cost and easily available materials like earthen jar, coalter coated earthen jar, biscuit tin, kerosene tin, metal dram, gunny bag, polythene bag, dole, cow dung coated dole etc. are used as storage containers (hossain, 1978). the farmers have different types of storage containers in order to protect the seed from moisture absorption and insect infestation. storage container had significant effect on moisture content of wheat seed at different observation date of storing (rahman et al., 2010). seeds packed in polythene maintained high viability with time due to minimized moisture fluctuation and consequently produced more vigorous seedlings compared with those from seeds stored in jute or cloth bags which had little protection against moisture fluctuation (karim et al., 2005). starchy seeds above 12% moisture and oily seeds above 9% moisture should not be packed in moisture resistant containers. if seed could be packaged in moisture proof containers so that the relative humidity of the air around the seed remains low, then the seed equilibrium moisture remains low and the seed maintains its viability and vigour for a longer time (poonam et al., 2001; agha et al., 2004). the physical properties and storage potential of seed were influenced to a very large extent by moisture content and the relative humidity of the atmosphere surrounding the seed (kong et al., 2008). poor storage conditions greatly affect seed vigor (simic et al., 2007). clay pots and gunny bags showed an increase in moisture content and sharp decline seed viability within a year of storage than air tight tin cans and air tight glass jar (naznin, 2005). in sealed containers, dry seeds can not absorb moisture from the external atmosphere (karim et al., 2005). krishnappa et al. (2002) found that groundnut seed stored in polyvinyl bag at 7% moisture content should the highest germination. reports are also available that polythene bags can be used as moisture proof container (alam and rahman, 2005). adequate dried seeds in sealed containers usually live longer at a given temperature than similar seeds in open containers. soybean seeds stored in moisture proof containers retain high viability than those in moisture permeable containers (tatipata, 2009). use of proper storage container to maintain the quality of farmers stored seed and preserving the seed viability should be an important consideration to reduce seed loss and increase crop yield (samajpati et al., 1978). in view of the above facts, the present study was undertaken to determine appropriate moisture content for seed storage and storage container for reducing the loss of soybean seed viability. . materials and methods an experiment was conducted at regional agricultural research station farm, jamalpur during the period from may to december 2011 and 2012 with a view to study the effect of storage container and initial seed moisture content on germination and vigour of soybean seed. soybean variety shohag (pb1) collected from bangladesh agricultural research institute (bari), joydebpur, gazipur. the crop was grown with proper agronomic management. the crop was harvested at full maturity and after proper processing, cleaning and drying the seed was stored in polythene bags until used for experimentation. the seed was dried in the sun on a triple set on the cemented floor to about 8% seed moisture content (smc) in the 1st year and 6.5% smc in effect o seed moisture content and storage container 133 the 2nd year. just before final storage the seed was re-hydrated at 70% rh for required period of time to obtain target moisture content of 8, 10 and 12% for the 1st year and 6.50, 8, 10 and 12% for 2nd year. four types of storage containers viz., polythene bag, plastic pot, tin can and glass jar were used in the experiment. the seed (500 g) was stored in the respective containers on 14 may 2011 and 18 may 2012 respectively. each container was completely filled with seed as per experimental specification and then made air tight. the experiment was arranged in a factorial completely randomized design with three replicates. the seed was tested for different quality parameters at 40, 80, 120, 160 and 200 days after storage (das). the containers were kept in the laboratory under ambient room condition. the quality parameters tested were seed moisture content, germination percentage, vigour index, and seedling dry matter. seed moisture content was measured using high constant temperature oven dry method following ista rules (1999). about 5-8g of seeds were taken in the aluminum dish and dried in the oven at 130 oc for 2 hours (until constant weight reached). then the moisture content was calculated as follows: w1-w moisture content (%) = ----------100 w1-w2 where, w = weight of blank aluminum dish with lid w1 = weight of seed plus aluminum dish with lid before drying w2 = weight of seed plus aluminum dish with lid after drying germination percentage germination test was done in sand culture method. two third of a plastic dish (20 cm diameter and 15 cm deep) was filled with sterilized sand having 60% water holding capacity. randomly collected 100 seeds from each container were placed into the sand for the germination test. the germination dishes were placed in the germination cabinet and seedling evaluation was done at 8 days after placing the test. the number of normal seedlings per dish was regarded as the germination percentage. germination index (gi) germination index of seed was estimated from the seed set in the germination test by calculating the germination index following the formula below given by association of official seed analysts. the number of seedling was counted at each day at the same time from the day after seed set until the last count was made. the seedling emerged each day having plumule length of 2 cm or more was considered as germinated. germination index = lcountdaystofina ntatfinalcouofseedlingno stcountdaysto stcountatofseedlingno . 1 1.  seedling dry matter the normal seedlings from each germination dish was collected and washed with running tap water and surface dried. then the seedling was dried in the oven at 70 oc temperature for 48 hours (until constant weight reached). data analysis was done statistically following the analysis of variance (anova) technique and the means were compared by duncan’s multiple range test (gomez and gomez, 1984). results and discussion seed moisture content (smc) 134 ali et al. storage container and initial seed moisture content had significant effect on final seed moisture content of soybean seed at 40, 80, 120, 160 and 200 das in 2011 and 2012 (table 1). in 2011, the lowest seed moisture content of seeds stored in glass jar at 8% initial smc were 8.08, 8.21, 8.31, 8.51 and 8.73% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 1.00, 2.63, 3.87, 6.37 and 9.12% while the highest seed moisture content was observed from those seeds stored in metallic can at 12% initial smc were 12.64, 13.08, 13.51, 13.87 and 14.15% at 40, 80, 120, 160 and 200 das, respectively and % moisture increased 5.33, 9.00, 12.58, 15.58 and 17.92% (table 1). this result are in agreement with the findings of naznin (2005) who reported that air tight tin can showed an increase in moisture content and sharp decline seed viability within a year of storage than air tight glass jar. in 2012, the lowest seed moisture content of seeds stored in glass jar at 6% initial smc were 6.57, 6.61, 6.83, 7.12 and 7.38% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 0.87, 1.83, 5.50, 10.33 and 14.67% while the highest seed moisture content was observed from those seeds stored in metallic can at 12% initial smc were 12.40, 12.66, 13.02, 13.45 and 13.85% at 40, 80, 120, 160 and 200 das, respectively and % moisture increased 3.33, 5.50, 8.05, 12.08 and 15.42% (table 1). germination percentage storage container and initial seed moisture content had significant effect on final seed moisture content of soybean seed at 40, 80, 120, 160 and 200 das in 2011 and 2012 (table 1). in 2011, the lowest seed moisture content of seeds stored in glass jar at 8% initial smc were 8.08, 8.21, 8.31, 8.51 and 8.73% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 1.00, 2.63, 3.87, 6.37 and 9.125% while the highest seed moisture content was observed from those seeds stored in metalic can at 12% initial smc were 12.64, 13.08, 13.51, 13.87 and 14.15% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 5.33, 9.00, 12.58, 15.58 and 17.92% (table 2). this result are in agreement with the findings of naznin (2005) who reported that air tight tin can showed an increase in moisture content and sharp decline seed viability within a year of storage than air tight glass jar. in 2012, the lowest seed moisture content of seeds stored in glass jar at 6% initial smc were 6.57, 6.61, 6.83, 7.12 and 7.38% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 0.87, 1.83, 5.50, 10.33 and 14.67% while the highest seed moisture content was observed from those seeds stored in metalic can at 12% initial smc were 12.40, 12.66, 13.02, 13.45 and 13.85% at 40, 80, 120, 160 and 200 das, respectively and percent moisture increased 3.33, 5.50, 8.05, 12.08 and 15.42% (table 2). germination index the interaction effect of initial seed moisture content and storage container on germination index was statistically significant at each of the observation dates during the storage period both in 2011 and 2012. the interaction of glass jars with 8% initial smc showed higher germination index than metallic can container with 12% initial smc at each of the observation dates for both the years. in 2011, the germination index of seeds kept in glass jar with 8% initial smc were 25.41, 21.26, 17.53, 14.15 and 10.44 at 40, 80, 120, 160 and 200 das, respectively and it was statistically similar to 8% initial smc in polythene bag and plastic pot at each of the observation dates and those seeds stored in metatlic can container with 12% smc were 2.11 and 0.09 at 40 and 80 das, respectively. those seeds stored in metallic can, plastic pot and polythene bag with 12% initial smc completely lost viability at 120 das and no seedling was found (table 3). in 2012, the germination index of seeds kept in glass jar with 6% initial smc were 30.69, 29.22, 25.32, 21.76 and 12.58 at 40, 80, 120, 160 and 200 das, respectively and it was statistically similar to those seeds stored in polythene bag and plastic pot with 6% and 8% initial smc. the corresponding values for seeds stored in metallic can container with 12% initial smc were 20.85, 16.49, 10.48, 3.61 and 0.60 at 40, 80, 120, 160 and 200 das, respectively (table 3). effect o seed moisture content and storage container 135 seedling dry matter the interaction of initial seed moisture content and storage container had significant effect of on seedling dry matter at each of the observation dates during the storage in 2011 and 2012. the interaction effect of glass jar with 8% initial smc showed higher seedling dry matter than metalic can container with 12% initial smc at each of the observation dates for both the years. in 2011, the seedling dry matter of seeds in glass jar with 8% initial smc were 0.127, 0.124, 0.122, 0.117 and 0.112 g seedling-1 at 40, 80, 120, 160 and 200 das while those values for seeds stored in metallic can container with 12% initial smc were 0.078 and 0.076 g seedling-1 at 40 and 80 das, respectively. seeds with 12% initial smc stored in metalic can, plastic pot and polythene bag completely lost viability at 120 das and no seedling was found (table 4). in 2012, the seedling dry matter of seeds in glass jar with 6% smc were 0.116, 0.112, 0.108, 0.106 and 0.101 g seedling-1 at 40, 80, 120, 160 and 200 das while those values for seeds stored in metallic can container with 12% initial smc were 0.086, 0.084, 0.080 and 0.077 g seedling-1 at 40, 80, 120 and 160 das, respectively and it was statistically at par to plastic pot and polythene bag with 12% initial smc. those seeds stored in metalic can, polythene bag and plastic pot with 12% initial smc completely lost viability at 200 das and no seedling emergence was found (table 4). 136 ali et al. table 1. interaction effect of initial seed moisture content and storage container on final seed moisture content of soybean seed at different days after storage (das) storage in 2011 and 2012 initial smc × container seed moisture content (%) 2011 2012 40 das 80 das 120 das 160 das 200 das 40 das 80 das 120 das 160 das 200 das m1c1 6.58d 6.72i 6.89l 7.29e 7.85gh m1c2 6.59d 6.75i 6.99k 7.32e 7.78gh m1c3 6.68d 6.93h 7.25j 7.77de 8.23fg m1c4 6.57d 6.61j 6.83m 7.12e 7.38h m2c1 8.15g 8.42h 8.58h 8.87j 9.12j 8.14c 8.44h 8.66h 8.87d-e 9.09e m2c2 8.15g 8.30i 8.46h 8.70k 8.92k 8.11c 8.24g 8.36i 8.49cde 8.80e m2c3 8.33f 8.73g 9.18g 9.46i 9.93i 8.19c 8.42f 8.84g 9.14b-e 9.69d m2c4 8.08g 8.21i 8.31h 8.51l 8.73l 8.10c 8.22g 8.35i 8.50cde 8.70ef m3c1 10.20e 10.46e 10.77e 11.06f 11.42f 10.39b 10.60d 10.92d 11.24ab 11.64b m3c2 10.14e 10.38ef 10.63ef 10.94g 11.25g 10.34bb 10.56d 10.78e 11.12ab 11.59b m3c3 10.49d 10.75d 11.33g 11.34e 11.71e 10.31b 10.57d 10.89d 11.23ab 11.77b m3c4 10.07e 10.32f 10.42f 10.61h 10.90h 10.21b 10.32e 10.45f 10.61bc 10.90c m4 c1 12.27b 12.61b 12.86b 13.11b 13.40b 12.38a 12.5b8 12.92b 13.31bcd 13.67a m4 c2 12.20bc 12.43c 12.75b 12.90c 13.14c 12.35a 12.46c 12.80c 13.15a 13.62a m4 c3 12.64a 13.08a 13.51a 13.87a 14.15a 12.40a 12.66a 13.02a 13.45a 13.85a m4 c4 12.11c 12.34c 12.45c 12.62d 12.83d 12.33a 12.56b 12.79c 13.10a 13.51a cv (%) 6.79 5.70 4.45 8.49 7.51 5.93 7.40 6.27 4.20 7.71 in a column, values having similar letter(s) do not differ significantly by dmrt note:c1= polythene bag, c2= plastic pot, c3= metalic can, c4= glass jar, m1= 6.5 mc, m2= 8% smc, m3=10% smc, m4= 12% smc effect o seed moisture content and storage container 137 table 2. interaction effect of initial seed moisture content and storage container on germination and field emergence of soybean seed at different das in 2011 and 2012 initial smc ×container germination (%) 2011 2012 40 das 80 das 120 das 160 das 200 das 40 das 80 das 120 das 160 das 200 das m1c1 94.7abc 93.3a-e 92.7ab 90.7abc 90.0a m1c2 97.3a 96.0ab 93.3ab 92.7ab 91.3a m1c3 91.3a-d 90.0b-e 88.0bc 85.3bc 80.0b m1c4 97.3a 96.7a 96.0a 95.3a 94.0a m2c1 89.7ab 88.0ab 86.0ab 83.3ab 80.0ab 94.00abc 94.7abc 93.3ab 91.33abc 90.3a m2c2 90.0ab 89.0a 87.0ab 84.7ab 82.3ab 94.7abc 94.0a-d 92.7ab 92.0abc 90.7a m2c3 86.0ab 84.3abc 81.0bcd 79.3bc 77.3bc 88.7cd 88.0de 85.3c 84.7c 75.0b m2c4 91.7a 90.7a 89.0a 87.0a 85.0a 95.3ab 94.0a-d 93.3ab 92.7ab 91.3a m3c1 84.3b 78.7c 55.0d 71.0d 68.0d 88.7cd 91.3a-e 69.33d 55.3de 44.7c m3c2 85.3b 81.3bc 76.7cd 74.0cd 72.7cd 94.0abc 88.7cde 65.3de 47.3f 42.0c m3c3 75.7c 70.3d 63.3e 58.3e 52.7e 88.7cd 87.3e 50.0f 48.7cf 46.7c m3c4 87.3ab 84.7abc 82.3bc 83.3ab 78.3b 91.3a-d 90. 7a-e 59.3e 57.3d 54.0c m4 c1 24.7f 6.7f 0.0g 0.0g 0.0g 86.0d 72.0fg 52.0f 26.0g 10.7d m4 c2 37.3e 9.3f 0.0g 0.0g 0.0g 88.7cd 72.7f 50.0f 24.7g 10.0d m4 c3 19.3g 2.7f 0.0g 0.0g 0.0g 75.0fg 66.0g 40.0g 16.7h 9.3d m4 c4 58.3d 46.7e 37.0f 29.0f 21.0f 89.3bcd 70.7fg 41.3g 24.0gh 22.0d cv (%) 4.46 6.58 6.12 6.25 6.16 4.82 5.27 5.29 7.08 9.76 das= days after sowing, in a column, values having similar letter(s) do not differ significantly by dmrt note: c1= polythene bag, c2= plastic pot, c3= metallic can, c4= glass jar, m1= 6% smc, m2= 8% smc, m3=10% smc, m4=12%smc 138 ali et al. table 3. interaction effect of initial seed moisture content and storage container on germination index of soybean seed at das storage in 2011 and 2012 initial smc ×container germination index 2011 2012 40 das 80 das 120 das 160 das 200 das 40 das 80 das 120 das 160 das 200 das m1c1 29.01abc 28.95a 24.29ab 21.44a 12.05a m1c2 29.74abc 28.98a 21.52a-d 19.85ab 11.88a m1c3 28.11a-e 26.41bc 18.04d-h 15.73cd 9.27b m1c4 30.69a 29.22a 25.32a 21.76a 12.58a m2c1 25.22a 20.75ab 16.13ab 13.27b 9.89ab 28.34a-d 27.15ab 21.43a-d 20.25ab 10.12ab m2c2 24.41a 22.00a 16.95ab 13.78ab 10.23a 28.92a-d 28.55a 20.67a-f 18.27a 10.56a m2c3 23.35ab 20.25ab 15.21b 11.46c 9.13b 26.50cde 23.21d 16.64e-h 15.79cd 8.57b m2c4 25.41a 21.26ab 17.53a 14.15a 10.44a 29.28ab 28.69a 23.00abc 21.60a 10.30ab m3c1 22.80ab 17.00c 11.40c 8.62e 7.48c 25.85de 24.13d 20.41d-g 13.27de 4.05cde m3c2 23.12ab 17.41c 12.05c 8.90e 7.58c 27.92b-e 23.90d 19.40c-h 10.70ef 3.58cde m3c3 20.70b 14.35d 7.64d 6.23f 5.62d 27.90b-e 20.62e 11.63ij 8.43fg 5.57bcd m3c4 23.48a 19.43b 12.92c 9.66d 8.23c 29.23ab 25.01cd 21.07a-e 13.27de 5.64bcd m4 c1 6.04d 0.64f 0.00f 0.00f 0.00f 21.84df 19.84e 15.83ghi 8.75f 0.94de m4 c2 6.01d 0.67f 0.00f 0.00f 0.00f 25.54e 19.72e 15.07hij 5.57gh 095e m4 c3 2.11e 0.09f 0.00f 0.00f 0.00f 20.85b-e 16.49f 10.48j 3.61h 0.60e m4 c4 10.44c 9.83e 4.39e 2.50g 2.31e 27.04b-e 19.18e 16.13f-i 9.80f 8.01abc cv (%) 8.60 8.60 6.34 5.46 8.34 5.57 5.11 7.76 8.04 6.04 das= days after sowing, in a column, values having similar letter(s) do not differ significantly by dmrt note: c1= polythene bag, c2= plastic pot, c3= metalic can, c4= glass jar, m1= 6% smc, m2= 8% smc, m3=10% smc, m4= 12% smc effect o seed moisture content and storage container 139 table 4. interaction effect of initial seed moisture content and storage container on seedling dry matter (g) of soybean at different das during storage in 2011 and 2012 initial smc ×container seedling dry matter (g seedling-1) 2011 2012 40 das 80 das 120 das 160 das 200 das 40 das 80 das 120 das 160 das 200 das m1c1 0.113b 0.111a 0.104ab 0.098d 0.093c m1c2 0.114ab 0.107b 0.105a 0.103bc 0.099b m1c3 0.095b 0.106b 0.101abc 0.092e 0.086d m1c4 0.116a 0.112a 0.108a 0.106a 0.101a m2c1 0.112b 0.111c 0.108c 0.104c 0.099c 0.112b 0.110ab 0.100a-d 0.086f 0.055f m2c2 0.123a 0.119b 0.116b 0.122b 0.106b 0.109b 0.104c 0.104ab 0.101c 0.088cd m2c3 0.104c 0.107d 0.103d 0.099d 0.093d 0.094b 0.106b 0.098a-d 0.091e 0.084e m2c4 0.127a 0.124a 0.122a 0.117a 0.112a 0.111b 0.106b 0.101abc 0.100c 0.098b m3c1 0.102c 0.101e 0.098e 0.093e 0.087e 0.104b 0.100cd 0.087bcd 0.085f 0.054f m3c2 0.114b 0.111c 0.108c 0.103c 0.097c 0.107b 0.103c 0.087bcd 0.087f 0.081e m3c3 0.096d 0.094f 0.091f 0.086f 0.079f 0.086c 0.104c 0.097a-d 0.090e m3c4 0.116b 0.113c 0.110c 0.106c 0.100c 0.110b 0.103c 0.100a-d 0.098c 0.095c m4 c1 0.081g 0.080h 0.000h 0.000h 0.000h 0.100b 0.099d 0.084cd 0.084f m4 c2 0.084ef 0.082h 0.000h 0.000h 0.000h 0.092b 0.096e 0.084d 0.083f m4 c3 0.078g 0.076c 0.000h 0.000h 0.000h 0.086c 0.084e 0.080d 0.077g m4 c4 0.088e 0.086g 0.082g 0.076g 0.065g 0.109b 0.103c 0.092a-d 0.097d 0.084e sign. level ** ** ** ** ** ** ** ** ** ** cv (%) 4.86 6.00 7.60 8.61 5.91 6.92 7.04 8.63 5.73 8.09 das= days after sowing, in a column, values having similar letter(s) do not differ significantly note: c1= polythene bag, c2= plastic pot, c3= metallic can, c4= glass jar, m1= 6% seed moisture content (smc), m2= 8% smc, m3=10% smc, m4= 12% smc, 140 ali et al. conclusion it is concluded that seeds stored in polythene bag or plastic container showed the germination performance similar to those in glass jar. thus, the study revealed that soybean seed can be stored in polythene bag or plastic pot after drying to 6 to 8% smc for retaining high viability. reference agha, s. k., z. h. malik, m. hatam and g. h. jamro. 2004. emergence of healthy seedlings of soybeans as influenced by seed storage containers. pakistan j. biol. sci. 7(1): 42-44. alam, m. m. and m. m. rahman. 2005. effect of seed moisture content and thickness of polythene bag on germination and vigour on soybean seed. bangladesh seed sci. technol. 9(1& 2): 3338. arulnandhy, v. and y. d. a. senanayaka, 1991. changes in viability, vigour and chemical composition of soybean seeds stored under the humid tropical conditions. legume res. 14(3):135-140. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research 2nd edn. john willy and sons., new york. pp. 97-111. hossain, s. m. a. 1978. storage environment of seeds. in: lecture on seed production and certification. gti, bangladesh agric. univ. mymensingh. pp. 87-92. ista (international seed testing association). 1999. international rules for seed testing, 1999. supplement to seed science and technology. 27: 27-32. karim, m. r., m. a. rahim and g. a. fakir. 2005. effect of storage containers on seed quality of onion. bangladesh j. seed sci. technol. 9(1&2): 27-31. kong, f., s. k. c. chang, z. liu and l. a. wilson. 2008. change of soybean quality during storage as related to soyamilk and tofu making. j. food sci. 73(3): 134-144. krishnappa, a. p., i. a. adeyemi and o. a. olorunda. 2002. effect of processing conditions and packaging material on the quality attributes of groundnut. j. sci. food agric. 82: 1465-1472. naznin, h. a., m. s. monjil, m. a. kashem, m. r. islam and j. hossain. 2005. quality of wheat seeds stored in different containers. bangladesh j. seed sci. technol. 9(1&2): 15-18. poonam s., n. tewari, p. k. katiyar, t. das and c.p. vaish. 2001. storability of soybean (glycine max merr.) seeds in different containers under ambient conditions. progres. agric. 1(1): 9093. rahman, m. m., b. hagidok, m. m. masood and m. n. islam. 2010. effect of storage container and relative humidity on the quality of wheat seed. bangladesh j. seed sci. technol. 14(1&2): 89-94. samajpati, j. n., m. s. rahman and t. c. choudhury. 1978. comparative study of low cost grain storage structure for domestic use in bangladesh. research report. department of agricultural engineering. bangladesh agricultural university, mymensingh. p. 72. simic, b., r. popovic, a. sudaric, v. rozman, t. kalinovic and j. cosic. 2007. influence of storage condition on seed oil content of maize, soybean and sunflower. agriculturae conspectus scientificus poljoprivredna znanstvena smotra. 72(3): 211-213. tatipata, a. 2009. effect of seed moisture content packaging and storage period on microchondria inner membrane of soybean seed. j. agric. technol. 5(1): 51-54. microsoft word final.doc �������� ��� ������������������������� ��� !"#$%$#&��'���#�#����� !"#$%$#&��'���#�#����� !"#$%$#&��'���#�#����� !"#$%$#&��'���#�#����������(&��$ �)�$*+��+,�&�"����$-.�(&��$ �)�$*+��+,�&�"����$-.�(&��$ �)�$*+��+,�&�"����$-.�(&��$ �)�$*+��+,�&�"����$-.� /&/#+)��/�$-',!+-"+ ��&�'+�#$,$*+�� �/+/&/#+)��/�$-',!+-"+ ��&�'+�#$,$*+�� �/+/&/#+)��/�$-',!+-"+ ��&�'+�#$,$*+�� �/+/&/#+)��/�$-',!+-"+ ��&�'+�#$,$*+�� �/+���� ���� ������������0000��������))))��������////��������(�12�(�12�(�12�(�12�������)��)��)��)��������----��������$ ��3$ ��3$ ��3$ ��3������)��)��)��)��������((((��������(� �4�(� �4�(� �4�(� �4�������������)����)����)����)��������������������((((��������0 ��0 ��0 ��0 ���������� �� 4�546���/54��74845��8845� ����/�����$��"�34������� 4�546���/54��74845��8845� ���� ���39� 4:4 4�������$��.�;462 �� �/��4� �/54��74845��8845� ���'� �����$��"�34������/54��74845��8845� ����/�����$��"�34���� "� � 6���4����27 � ���92<�� ���39=9� ���5�3� 0�9�>� � 0�9�>� � 0�9�>� � 0�9�>� � ����7�7���3�4;��� ���9�5 �664����8� 74�4;� ��� �� � �< 7 �5�< 7 �5�< 7 �5�< 7 �57777���� ���� # ���?6� 43��7�>� �5���257����7� � �� 5 �84�����8��� 452�72 ����� �� 5 �/7�74�������$�� "�34�����2 4���-�:�3<� ������7���2��������>47 ���:4�>�7��84����27��5���345�8� 74�4;� � �� ��8� �6�7�7��� 9< 4��3�4;�� ���9�5 �664��� 9 7�3��# ��6�7�7��:� 4�79����$���2������� 7 ��3�4;��:� 4�79����$�(9< 4��)�4;����>� ��2 ����/�:���8� 74�4;� �5�3<4��74�� �:4;��#�@� '� 3� �8� 74�4;� ��� ���8�6�7�7���'' ���a�>47 �27����474�����8� 74�4;� �8� �3�4;���b�')��� #�@� '' �� a� ���c� -� �8� �5�33������ 8� 74�4;� � �� �� �8� 9< 4�� 3�4;�� ��' )��� #�@� '' �� a� ���c�-�d� �ec� �7 � � �8� �' )�� #�@� '' �� a� ���c�-�d� e�c� �7 � � �8� �' )��#e@���5�33������ 8� 74�4;� � �� �� �8� 6�7�7�� ��' ���a���c�-��8��' )��#f@� �' ��a���c�-�d��ec��7 � ��8��' )�����#�@��' ��a���c�-�d�e�c��7 � ��8� �' )�>� ��7� 7������6�7�7�� 9< 4��3�4;�� ���9�5 �664��� 9 7�3��'� 3� g �8� 74�4;� ��� �� 8� �6�7�7��>� �e����f������h�� ����-�0����5�33������8� 74�4;� ��� ��8� �6�7�7������ 9< 4�� 3�4;�� >� � ��i�����������f����� h�� ���� -�0/*��� ���� �ee�ee��������f��� h� ���� -�0/*���� � 6�574:��9�� # �� 4� � 7� 6�7�7�� �124:����7� 94���� ����i�� 7� ����� ���� � � � �72 �� ���e��f���#h�� �����>� �� �<7�4���� 8 �3�#�� 7 ��73��7���27� 7 ��3�?4323� � � � 3� �4�� �#h�� �������e� #h�� ����� >� � 8�2��� 8 �3� 7 ��73��7� #�� ���� 7 �� 4� � 7� <���847� 5� 7� �74�� �������>� ��< � :��� 4��#e�> 45 �>� �5�� �� 7��#�� ����f������#f� ������ �# �� � 2�7 � �:������ 7 �7� �5�33������ 8� 74�4;� � �� �� �8� 6�7�7�� ���� ���c� -� 8 �3� �5�33������8� 74�4;� ��� ���8� 9< 4��3�4;��34� 7�<��2 ���8� �6�7�7�� 9< 4��3�4;�� ���9� 5 �664��� 9 7�3�8� ���774��� 4� � ��5���345� �72 ���7�"�34���� ��4���� ���� $�7 ��2574��$�7 ��2574��$�7 ��2574��$�7 ��2574������ ���� ��7�7�� 4 � �� 72<� � 5 �6� �:4���6�7��74��� 94�����8��e��e� 7� ���� 4���������� ��(9< 4��3�4;�� 4 � �� 5� ���� 5 �6�>47 � 5�6�5479� �8� 6 ��254��� �<�27� i���� 7� ���� �8� � �4�� 94����� ��7 � 7 �� 5 �6 � �:�� �4:� 484���2 � �������>4��� ������8�6 ��2574���� ��� 4���2 �5�2�7 9����7�7������3�4;��3�9�<�� � �>��� � ���9�5 �6�� �7 �9� �:���488� ��7�� �>7 � �<47������ �>7 ��2 �74������7�7��3�4;�� ���9� 5 �664��� 4 � �� 9 7�3� 4�� > 45 � 3�4;�� 4 � �>�� �87� � �77�4�4��� 7 �� �6 ��2574:�� 7���� � � <�8� �� 3�72 479��8�6�7�7���# 4 � ���9�5 �664���6 �5745�� 4 ���5�33�������6�62�� �6 �5745�� 4���488� ��7� ��5�74���4���2 �5�2�7 9��# ��>4�� �6���7� 6�54����8� 9< 4��3�4;��6 �:4�� �8�54�479��8��7 � �5 �6 � 8� � � �>4��� � � 4�7� � � � ���9� 5 �664��� >47 � 47� �� 3��� �7� ����� ������� '� 3� � 4�� �3�� � ��� 6 �5745��7 4 � 9 7�3�7���:�4���� �9�8������ �>����� �� �2� 7��# �9� �>�3�4;������e���9 �<�8� �� 6�7�7�� � :� 7� � 2�74��� 4� � � � �4�� 94���� 5�36� ��� 7�� 3�4;�� �>�� �87� � 6�7�7�� � :� 7�� )� ��:� �� 8� 74�4;� � �66�45�74��� 4 � ��� �674��� 8� � 4�5 �� 4��� 6 ��2574:479� �8� 6�7�7�� 9< 4��3�4;�� ���9�5 �664����� ��48��595����8�6�7�7������ 9< 4��3�4;��4 ��488� ��7�� ��7 ��8� 74�4;� � �124 �3��7� ����47 �3�����3��7�6 �5745� ��� ��:� 9���$ ��3��7�������������)� 7��8�7 ��8� 3� ��8�7 � ��� �� � 2 �� � 4�2���8� 74�4;� �4��6�7�7��<27�7 �9������7�2 ����9�8� 74�4;� �� ����9��477����3�2�7��8�-�8� 74�4;� � 8� � 3�4;�� 2��� � ���9� 5 �664��� 9 7�3��)� ��:� �� 6�47� �66�45�74��� �8� 8� 74�4;� � 7�� 5�36����7� 5 �6 �4�5 �� ���7�7���6 ��2574:479�� �>����� �8� 74�4;� �2 ���88454��59�7 �2� � ��254������5 4����� � ��� (�12���7����� �8� �27 4��7 � �.4��� ���� � 3���� ��iej� "� �77�� �7� ����� ������� (�>�:� �� �47� �72 � � ��� �4��� �5���345� 8� 74�4;� � 3�����3��7� 8� � 6�7�7�� 9< 4�� 3�4;�� ���9� 5 �664��� 9 7�3� � �� 3���� �� # � �8� ���7 ���?6� 43��7�>� �5���257���7��84����27��5���345�8� 74�4;� ��� ������3�����3��7� 6 �5745� �8� �6�7�7�� 9< 4��3�4;��� � ���9�5 �664��� 9 7�3��� � )�7� 4�� �����)�7 �� )�7� 4�� �����)�7 �� )�7� 4�� �����)�7 �� )�7� 4�� �����)�7 �� ���� ���� # ���?6� 43��7�>� �5���257����7� � �� 5 �84�����8��� 452�72 ����� �� 5 �/7�74�������$��"�34���� �2 4���-�:�3<� � ����� 7�� �2��� ������ # �� �?6� 43��7�>� � ��4�� �27� 4�� ����34;��� 5�36��7�� <��5h��� 4���>47 �7 ��� �6�45�74�� ���# ��2�47�6��7� 4;��>� ��3�?��3��$��5� ���8�6�7�7���7 �� �>� 7�� �>��4 7��5��>� �f�53�����6���7�7��6���7��4 7��5��>� ��e53���/�:���7 ��73��7 ���3��9�#�@� '� 3� � 8� 74�4;� ��� ���8�6�7�7�� �'' ���a�>47 �27����474����� 8� 74�4;� � 8� �3�4;�� �b�')����#�@� '' ��a����c�-��8� �5�33������8� 74�4;� ��� ���8� 9< 4��3�4;����' )���#�@�'' ��a����c�-� d��ec��7 � ��8��' )��#�@�'' ��a����c�-�d�e�c��7 � ��8��' )��#e@���5�33������ 8� 74�4;� � �� �� �8� 6�7�7�� ��' ���a���c�-��8��' )�� #f@��' ��a���c�-�d��ec��7 � � �8� �' )�����#�@��' ��a���c�-�d�e�c��7 � ��8��' )��'' �@�'� 3� �'� 74�4;� � � ���8� ��7�7��@�e����f������h�� �����8�-�0��'' )@�'� 3� �'� 74�4;� � � ���8� 9< 4��3�4;��@������ h�� �����8�-�0���' �@���5�33������'� 74�4;� � � ���8���7�7��@���i�����������f�����h�h�� ����-�0/*�����' )@���5�33������'� 74�4;� � � ���8�)�4;��@��ee�ee��������f���h�� ���� -�0/*����# ��72<� ��8�6�7�7��:� 4�79����$���2���>� ��6���7���������-�:�3<� ��������# �� 8� 74�4;� � >� �� �66�4��� �55� �4��� 7�� 7 �� 7 ��73��7 �� ��2�4���� 4 4��74��� ���� �7 � � 4�7� 52�72 ��� �6� �74�� � >� �� ����� � � ���� > ��� ��5� � 9�� $� �57454��� ���34 ��� >� � 6 �9��� �� 743� �� <��4��4���8 �3��e���9 ��87� �6���74��� � �����7��:� 9������9 � 4�7� :����'2��454��� � 4�7 ����)� �e��>� � 6 �9����7���� ���8� �6 �:��74����8��4 �� ������/�52 ��>� � 6 �9����7�����e������f�� ��9 � �87� � 6���74��� 8� � 6 �7�574��� �8� �4 �� ��� ���� ��5� � 9� ��7�� >� �� 7�h��� �7� 7 �� 6� 4��� �8� � :� 74����$��6�7�7��� ��8��8�-����������7 � �8� 74�4;� �>� ���66�4���� �<� ������ 7��3�2�7��8�-� >� �7�6�� � ����7������9 ��87� �6�7�7��6���74������7�7��>� � � :� 7����7������9 ��87� �6���74��� ����e�'�< 2� 9��������(9< 4��)�4;��:� 4�79����$�(9< 4��)�4;����>� � �>�� 4�� <�7>���� 7>�� 6�7�7�� �> ��87� ������9 ��8�6�7�7��6���74�������f�'�< 2� 9��������# �� ��� ��8�3�4;��>� �� 7 ��7���>47 ���:4 74��=�����,���8� �5��7 ���4���8��7����� ��7� �7��4 �� ���# ��4� �57454��� � <��� ����+"�=���e�3��,���>� � 6 �9����7��87� �����7 ���743� ��7�7 �� �7���8�e�3��,���8� �5��7 ���4��� 527>� 3��# �� �>�7�� �>��4 7��5��>� �f�53����� ����7�� �����4 7��5��>� ���53�� � 6�574:��9�� $��3�4;��� ��8��8�-����������7 � �8� 74�4;� �>� ���66�4���k2 7��87� �6�7�7�� � :� 74������ 7�-�>� � 7�6�� � ����87� ������9 ��8�3�4;�� �>4�����)�4;��>� � � :� 7�������2����������������� �/��� &4����5�36����7 ��8�6�7�7������3�4;��>� ��7�h���8 �3� ����3�9� ���57������6���7 �8 �3���5 � 6��7��&4��� ��8�<�7 �7 ��5 �6 �>� ��7�h���8 �3�> ����6��7��+124:����7�94��� �>� ��5�3627���2 4��� 7 �� 8� 32����8�����9�6�� �9�� ���i���� �7�����94���� ����94���� 5�36����7 ��8�<�7 � 7 ��5 �6 � >� �� ����9;��� 7�74 745���9� ���� 7 ��3��� �>� �� ��k2�����2 4���,/ � 7� 7������847�� 5� 7� ����9 4 � >� ��� �������� ���� �� 2�7 ����� 4 52 4���� 2�7 ����� 4 52 4���� 2�7 ����� 4 52 4���� 2�7 ����� 4 52 4������ ��7�7���7�7���7�7���7�7����� /4��4845��7��488� ��5� �>� ���< � :���4��94��������94����5��7 4<274���5 � �57� ��8�6�7�7���3���� 7 �� 7 ��73��7 � �#�<��� ���� # �� 4� � 7� 6���7� �4� 7� �f�� 53�� >� � �5� ���� 8 �3� #��� 7 �7� >� � 7�74 745���9� 434�� � 7�� #�� �f���� 53�� ���� #�� �e���� 53��� )�?4323� ������ ���� 34�4323� ���i�� �23<� ��8�72<� �6� �6���7�>� ���<7�4����8 �3�#���#������#f� � 6�574:��9�> � ��� �#������#�� >� � 7�74 745���9� 4���745���>47 �#e�����#���# �� 4� � 7�>�4� 7��8�72<� �6� �6���7� �f�i�e�����>� � �< � :���4��#��> 45 �>� � 7�74 745���9� 434�� �7��#���e�i�ff��������#���e���e���������7 ����>� 7� 8 �3�#�� ���e��f����� �# �� 4� � 7� 72<� �94���� ������ 7� �����>� ��<7�4���� 8 �3�7 �� 7 ��73��7�#�� ��� ��7�7��(9< 4��)�4;������9�" �664���� 7 �7�>� � 7�74 745���9� 434�� �7��#���������7� ������#���������7� ������#e���e�e��7� ���������#f���e��� 7� ���������7 ����>� 7��������7� �����8 �3�#���#���5 4�:�� 4� �72<� �12��479�47�4 � �5�33������7�� 8� 74�4;���� �>47 ��47 ���������7��4�5 �� ��6 � 6 � 2 �����6�7� 423�8� 74�4;� � �7� ��%� ��������� ���42�4��������*�h�47������i���< � :���7 �7��8�34�� ���8� 74�4;� ��7 ��3� 7��88�574:��>� ��8�2��� 7�� <�� 7 �� 6 � 6 � 2 � ���� 6�7� 423� 5�3<4��74�� �>47 � �47 ����� 8� 74�4;� �� 2��� � 7 �� �88�57� �8� > 45 �7 ��94��� �4�5 �� ���<9�������c�� � #�<������+88�57��8� 8� 74�4;� � �� �����94�������� 94���� �77 4<274���5 � �57� � �8�6�7�7���7� � �� 5 �������������� 84�����8���/��"�34�����2 4���7 �� �<4���������� '� 74�4;� ��� �� ����7� �4� 7� �53�� #2<� � 6���7��� ������ #2<� �>7���� 6���7��� ���� #2<� � 94���� �7� ����� #���'' ��a�b�')� f���� ����� f�i�e�� ������ #���'' ��a����c-��8��' )� f���� ����� e�i�ff� ������ #���'' ��a����c-�d��ec��7 � ��8��' )� e���� i�f�� e���e�� ������ #���'' ��a����c-�d�e�c��7 � ��8��' )� e���� i���� �����f� �e��f� #e���' ��a����c-��8��' )� e���� ����� e�e�if� �e�e�� #f���' ��a����c-�d��ec��7 � ��8��' )� e��i� ��i�� �i����� �e���� #����' ��a����c-�d�e�c��7 � ��8��' )� e���� ����� ��e��f� ������ ,/ ����e�� ����� ����� �f���� ����� "%��c�� ����� i���� ���f�� ��e�� '' �@� '� 3� � '� 74�4;� � � �� �8� ��7�7�� @� e����f������ h�� ���� �8� -�0��b�')@� >47 �27� ���474����� 8� 74�4;� � 8� � 3�4;��� �' �@� ��5�33������ '� 74�4;� � � �� �8� ��7�7�� @� ��i�����������f����� h�� ���� -�0/*���� �' )@� ��5�33������'� 74�4;� � � ���8�)�4;��@��ee�ee��������f���h�� ����-�0/*��� � (9< 4��3�4;�(9< 4��3�4;�(9< 4��3�4;�(9< 4��3�4;����� . �4�� 94��� � ���� 94���� 5�36����7 � �8� 9< 4�� 3�4;�� �4�� ��7� �488� � 8� � �488� ��7� 8� 74�4;� � 3�����3��7�6 �5745� ��#�<�������(�>�:� ��7 �� 4� � 7�5�< �3��� �������>� �8�2���8 �3�#������ 7 ����>� 7��������>� �8�2���8 �3�#f��# �� 4� � 7�� �4� �5�<����e�i��f��>� �8�2���8 �3�#������ 7 ����>� 7���ei�����>� �8�2���4��#���# �� 4� � 7�7 �2 ����� �4��>�4� 7���ii����>� �8�2���4��#e� ����7 ����>� 7���������4��#���# �� 4� � 7�� �4��94��������e��7� �����>� ��< � :���8 �3�#��> 45 � >� �8����>���<9�#���#e��#���#���#f�����7 ����>� 7�����f�7� �����>� �8�2���8 �3�#���"� �77���7����� ��������� �� �6� 7��� 4� � �� �4��94�����8�5� ���2��7�� 6�47��66�45�74����8�8� 74�4;� ��# 4 � � 2�7�>� � 266� 7���<9�7 ��84��4�� ��8�" �����7������������� � #�<������+88�57��8�8� 74�4;� ��� �����&4��������94����5�36����7 ��8� 9< 4��3�4;��4��6�7�7�� 9< 4�� 3�4;�� ���9�5 �664����7�"�34�����2 4���7 �� �<4����������� '� 74�4;� ��� �� "�< �3��� ������ . �4� �5�<��� ������ �����/���� >7������ . �4��94���� �7� ����� #���'' ��a�b�')� ����� e����f� �i����� ����� #���'' ��a����c-��8��' )� ����� �ei���� ������� ��if� #���'' ��a����c-�d��ec��7 � ��8��' )� ����� e������ ��f���� ���e�� #���'' ��a����c-�d�e�c��7 � ��8��' )� ����� e�e�e�� ������� ������ #e���' ��a����c-��8��' )� ����� e������ �ii���� ������ #f���' ��a����c-�d��ec��7 � ��8��' )� ����� ������� ��e���� ���e� #����' ��a����c-�d�e�c��7 � ��8��' )� ����� e�i��f� ������� ���f� ,/ ����e�� -/� -/� -/� -/� "%��c�� ��i�� ����� f���� ������ '' �@� '� 3� � '� 74�4;� � � �� �8� ��7�7�� @� e����f������ h�� ���� �8� -�0��b�')@� >47 �27� ���474����� 8� 74�4;� � 8� � 3�4;��� �' �@� ��5�33������ '� 74�4;� � � �� �8� ��7�7�� @� ��i�����������f����� h�� ���� -�0/*���� �' )@� ��5�33������'� 74�4;� � � ���8�)�4;��@��ee�ee��������f���h�� ����-�0/*��� ��� (�12���7����� ��7�7���124:����7��7�7���124:����7��7�7���124:����7��7�7���124:����7����94���94���94���94������� ��7�7�� �124:����7� 94���� ����<���847�5� 7� ����9 � � � ��6 � ��7��� 4��#�<������# �� 4� � 7� 6�7�7�� �124:����7�94��������i�7� �����>� � �5� ����8 �3�#������7 ����>� 7�8 �3�#���������7� ������# �� 7 ��73��7�#����:��7 �� 4� � 7�� � � �72 �����e��f���#h�� �����7 �7�>� �8����>���<9�#���#���#e�� #��� #f� ���� 7 �� ��>� 7� ���ii�fi�� #h�� ����� � 8 �3� #��� # �� 5� 7� �8� 52�74:�74��� >� � 3�?4323� ���f��i��� #h�� ����� 4�� #�� ���� 34�4323� ����e����� #h�� ����� 4�� #e�� # �� 5� 7� �8� 6 ��2574��� 3�4��9� 4�5 �� ���>47 � 7 �� 4�5 �� �� �8� 8� 74�4;� � 5� 7� � �>���� � � 4�:��:�3��7� �8�3� �� ��<�2 � 8� � 3�����3��7�6 �5745� ��# �� 4� � 7�� � �3� �4����������e�#h�� �����>� ��<7�4����8 �3�#������ 7 ����>� 7� ����������#h�� �����8 �3�#����)�?4323�<���847�5� 7� �74���������>� ��5 4�:���8 �3� #e�� > 45 � >� � 8����>��� <9� #��� #f�� #��� #��� #�� ���� 34�4323� ���e��� 8 �3� #�� 7 ��73��7�� �h 7� 2;;�3��� �7� ���� ����i�� �� �� �<7�4���� 3� �� <���847� 8 �3� 4�7� 5 �664��� �2�� 7�� k2�454�2 � �66�45�74����8�8� 74�4;� �� � #�<��� ��� ��7�7�� �124:����7� 94���� ��+&�� ���� <���847�5� 7� ����9 4 � �8� 6�7�7�� 9< 4�� 3�4;�� ���9� 5 �664���2��� ��488� ��7�8� 74�4;� �3�����3��7��7�"�34�����2 4���7 �� �<4��������� '� 74�4;� ��� �� �+&� �7 ����� . � � �72 �� �#h�� ����� "� 7��8� 52�74:�74��� �#h�� ����� . � � 3� �4�� �#h�� ����� �"�� #���'' ��a�b�')� ������ �����ii�� ���f�i�e� �������e� ���f� #���'' ��a����c-��8��' )� �f�if� ��������� ��e��ife� ��i���ee� ��i�� #���'' ��a����c-�d��ec��7 � ��8��' )� ���i�� ��e��f��� ��f��ii�� ��������� ���e� #���'' ��a����c-�d�e�c��7 � ��8��' )� �e��i� ���e��f�� ��f��i��� ��e��if�� ��e�� #e���' ��a����c-��8��' )� �e�e�� ���f����� ���e����� ��������� ����� #f���' ��a����c-�d��ec��7 � ��8��' )� �e��e� �����i��� ������fe� ��i����e� ����� #����' ��a����c-�d�e�c��7 � ��8��' )� ������ ��ii�fi�� ���e��i�� ��������� ��f�� )� h�7�6 45���#h��h��������7�7����l������)�4;����l��� '' �@� '� 3� � '� 74�4;� � � �� �8� ��7�7�� @� e����f������ h�� ���� �8� -�0��b�')@� >47 �27� ���474����� 8� 74�4;� � 8� � 3�4;��� �' �@� ��5�33������ '� 74�4;� � � �� �8� ��7�7�� @� ��i�����������f����� h�� ���� -�0/*���� �' )@� ��5�33������'� 74�4;� � � ���8�)�4;��@��ee�ee��������f���h�� ����-�0/*��� ���� "��5�2 4��"��5�2 4��"��5�2 4��"��5�2 4������ ���� �� ������7 ��6 � ��7� 72�9��47�3�9�<��5��5�2����7 �7� �5�33������8� 74�4;� ��� ���8�6�7�7������ ���c�-�8 �3� �5�33������8� 74�4;� ��� ���8� 9< 4��3�4;��5�2���<��2 ���8� �6�7�7�� 9< 4��3�4;�� ���9�5 �664��� 9 7�3�8� ���774��� 4� � ��5���345� �72 ������� ���� ��8� ��5���8� ��5���8� ��5���8� ��5� ���� ���� � 3���� '���)��-�� $ ��3��)��#���� 3����)����� �� ��� ����)�� /�����0 ���� ������ ,��8� � ��� 4���?�� ��4�74��� 4�7� 5�674���� � 9� 3�77� � 6 ��2574��� ���� � �4�� 94���� �8� 9< 4�� 3�4;�� � � 4�8�2��5���<9�6���7� 6�54������������ ��� ������������d�����e��ei����� �h 7� 2;;�3����)���)��-��$ ��3�����,��-�������)��#���� 3�������i��� ��2574:479��8�6�7�7�� 9< 4�� 3�4;�� ���9�5 �664���2��� ��488� ��7�8� 74�4;� ���:�� ��+5��8 4����9��� 4��������e������������ ����9�6�� 9�9�� /��-�� ��i���-47 ����� ����>�7� � ���74�� � 4�� � �4�� � � 23����23�� 4�7� 5 �664��� 9 7�3 ��� �� �� 4 � 7�74����$��4����� 452�72 ����� �� 5 �$� 74727���-�>� �� 4�� ���42�4�����������%��*�h�47������i��# ���88�57��8�34�� �������� ���45�8� 74�4;� ����6�7�7��72<� �94���� �����m2��479��,�7:4�������� �����-������,,!�����i�� ��� ��7�7��(9< 4��)�4;������9�" �664���� "� �77���"������"������� ������ 4�h�>��"���47������/����:4��7���'��"�����%4�4 ���+��������%��� 2 52���� ������-47 �����8� 74�4;� � 6�47��66�45�74���8� �5� ��4�����74��� 255� 4���7��<��5h���7 ��/54��74�� �� 45����e������e���ee��� " �����/������(��"��,���� ��(��/5� 4 < 45h�����'��+��#���� :�9����������7�7�� �/����23�72<� � 23�� 4�7� 5 �66���>47 �3�4;���*���3�9 ��4��7 ��+� 7� ��(4�� ��8�-�6������6��� �����# �6����� 45�� �e������f����e�� .4����)������������� 3������ie��+88�57��8� 6�47��66�45�74����8��47 �����2 �8� 74�4;� ����7 ��94��������� &4����5�36����7 ��8�> ��7����h4 7�������� 45���� ��f�����if�ii�� $ ��3��)��-���)���h 7� 2;;�3���������)��/�����3�����������/6�47��66�45�74����8�4�� ���45�8� 74�4;� �4�� 6�7�7���/����23�72<� � 23������� 9< 4��3�4;���*���3�9 �,���4�7� 5 �664��� 9 7�3���������� � ����� 4����� ���i����������e��� %� ��$��������/6�47��47 ������66�45�74���4��6�7�7����88�57 ��8��55232��74����47 ���������� 9�3�77� �4�� 7 ��5 �6��������7 �� �4���47 �����<2���7����2 ������ 45��/54����������� � � � � � � � � � � � � � � � � � � � � � � � � microsoft word final.doc �������� ��� ������������������������ ���� �!"��!#!�#�$��%& �#�'�'(�)�!"�#�$����� �!"��!#!�#�$��%& �#�'�'(�)�!"�#�$����� �!"��!#!�#�$��%& �#�'�'(�)�!"�#�$����� �!"��!#!�#�$��%& �#�'�'(�)�!"�#�$������&(�&'�"�$�(�!&�*�(+��&(�&'�"�$�(�!&�*�(+��&(�&'�"�$�(�!&�*�(+��&(�&'�"�$�(�!&�*�(+� �""�#�&(�*�(�#�#�,�)�'��& �)�&%#���'(�(%' �""�#�&(�*�(�#�#�,�)�'��& �)�&%#���'(�(%' �""�#�&(�*�(�#�#�,�)�'��& �)�&%#���'(�(%' �""�#�&(�*�(�#�#�,�)�'��& �)�&%#���'(�(%'���� ���� ���� )�����#� -��)�����#� -��)�����#� -��)�����#� -��������.��/���0 1� ��.��/���0 1� ��.��/���0 1� ��.��/���0 1� ���������/��)��#���-0������/��)��#���-0������/��)��#���-0������/��)��#���-0����������������2� ���������2� ���������2� ���������2� ��3333���� ��� ���-0 4���#�$��� 056�46 ��#� �� 5 ����� �7���8-��4�$��4 �����# $���,�9086 ���. �:� � �� �8� 4-��4��:� �� ���-;��'�%��3'��0� �'�54� �'8�50��0 4���#�$���65�40���. �� �-����.���)� �< ��0�� �<��� $� � 8���0����64 � ��=6�:0<� � � -��>? �5���4� /�;�1� � �/�;�1� � �/�;�1� � �/�;�1� � ��1�4� � ��0-���-��6 ��� 4�46 ��;0����8� :� -��5���'#����� � �? 4 �54�? 4 �54�? 4 �54�? 4 �54���� ���� �� :0���� �@8� 0-��4� 1� � 5� 0��� �64� �4� 4 �� �� ���-;� "0����� ' � ���������� �� 056�46 ��� %�07� 04;�� �<��: �-� �5�-?� �������4��)�;�������4�� 46�;� 4 ��;0�����:��� �� 05�� 6��� � ; 4�-��:� 05��0�4�� 0:05�40����'#���104 ��0::� ��4�1�4� � ��0-� �����-��6 ��� 4�46 �� ( �� �@8� 0-��4� 5�� 0 4��� �:� 41�� :�54� � � � 4 ��� 1�4� � ��0-�� 709��� 1�4� ������� 5���040����*���� �46 �4���5���040����*���������4� ��4��1�4������ ;�5���040����*3��0��4 �� -�0��8��4 ������ 0@�-��6 ������:� 40�09� �5�-?0��40�� �709���5�1�6������a��"����5�-8� 4� ���a��"����5 �-05���:� 40�09� ����a��"3���b�a�5 �-05���:� 40�09� �c��ba�5�-8� 4�c��ba� 5�1�6����"����b�a�5 �-05���:� 40�09� �c�b�a�5�1�6����"b������b�a�5 �-05���:� 40�09� �c� b�a�5�-8� 4��"d��0��4 �� 6?�8��4 ��*�4� � ��0-�� ��� 0��0:05��4��::�54����;0��������;0���� 5�-8����4 ��@5�84��6-?� ��:��::�5407��40��� �-����:0������ �0� �8��05������1�0� 4��:������ � �0�� ���� � 7� 4� 0���@�� ( �� 0� � 4� � �0�� ;0���� �b���� 4� ����� 1� � �?4�0���� : �-� 4 �� 1�4� ������� 5���040��� 4 �4� 1� � 4�40 405���;� 0-0�� � 104 � �46 �4��� 5���040��� �b�de��� 1 � �� ����4� ��4��1�4������ ;���* ����7��4 ����1� 4�� �0��;0�������3d�4� ������)��6 ��� 4�46 � �� �� 0��0:05��4�;� 0�:�6��5��� ;0���� �44 0?64� � �@5�84� ������ �0� � 1�0� 4�� ( �� 5�-?0��40����:�5 �-05���:� 40�09� ��5�1�6�������5�-8� 4� �1���4 ��?� 4�8� :� -��5�� 5�-8� ��� 4�� �4 � �-��6 ��� 4�46 �� ( �� 0� � 4� � �0�� ;0���� �b���� 4� ����� 1� � �?4�0���� : �-�5 �-05���:� 40�09� �b�a�c�5�1�6����ba�c�5�-8� 4��ba�����4 ����1� 4�� �0��;0���� ������4� �����1� ��?4�0����: �-�5�-8� 4����a��( �� 0� � 4��6-?� ��:��::�5407�� 40��� � 0����� �33����� 1� � �?4�0���� : �-� 5�-8� 4� ���a�� $ �-05��� :� 40�09� � b�a� c� 5�1�6��� �ba�c�5�-8� 4��ba� �1���4 �� 0� � 4� � 7� 4�0���@���d���a������5� ���:�0�4� �540��� �::�54� �:� 1�4� � ��0-�� ���� -��6 ��� 4�46 � 4 �� 0� � 4� � �0�� ;0���� 1� � �? � 7��� 0�� 5 �-05���:� 40�09� �b�a�c�5�1�6����ba�c�5�-8� 4��ba��:� �46 �4���5���040����d����4� ������� � ��4 ��6540����4 ��6540����4 ��6540����4 ��6540������ ���� #05�� 0 � 4 �� :� �-� 4� 4�8��� :���� :� �-� �� 4 ���b�a� �:� 4 ��1� ��f � 8�86��40��� �( �<6 � �4� ����� �������( � �� 0 � ���681� �� 0:4� 0����-���� :� � 05��1� ��10����6�� 4��8�86��40��� 0�5 �� ������ 6 ?��09�40���� � � 8��8��� 5 ����� 4 �0 � :���� �?04 � �)0 ��� ���e��� ����0��� 4�� 0� � ��:� 8 05� �� ��41���� ���d� ���� ������ �7� ���� 1� ��� 8 05� � :� � 05�� � �1� ?;� ���a�� 5�-8� ��� 4�� 1 ��4� 1 05 �0�5 �� ���?;��3da��5� ��?;���ba������ �;?��� �?;����a��"�!����������?�64��ba��:� 4 �� 4�4��� 5 �88��� � ��� ���� -� �� 4 ��� ��a� �:� 4 �� 4�4��� 0 0��4��� � ��� 0 � 8���4��� 4�� 05�� 0�� �������� � �+� �0�� ���� �?�� ���3�����-� 4� ���� �:� 4 �� �3�-0��0��� :� -� :�-0�0� � � �1� 05��� �4� 8 �70�� ���� �;���a��:���40������-8��;-��4����a��:� 6 ����-8��;-��4����?�64�����da��:�4�4��� 5��� 0�� 688�;�����dda��:�8 �4�0��0�4�<� ��:�����7� ����8� ���0��4 ��5�6�4 ;��+� �0������ �?�� ���3g�, ���:0�������� �1�0�����ee�g� �;��4�������eed���#05�� �54� �5��4 0?64� ����� ��:��:�4 �� �� 056�46 ���, .��������� 0@4 ��:�4 ����40�����0�5�-��0���������� ��+� �0����������( 6 �� 05�� 8��; ���704��� ����0��4 ���07��0 �����:�4 ��8��8����(��?���?���4��-��4�4 ��1� ��f �:������-����?;� ���b�� 04� 0 �� 40-�4���4 �4� 05��8 ��6540��� � � 4�� 0�5 �� �����?���;�?;�d�a��"��� 0�����������64� �� #� -����4����� 4 � �� 0 � �044��� 5�8�� 4�� 0�5 �� �� 4 �� � ��� 6��� � 05�� 8 ��6540���104 � 4 �� 56 ��4� 8 �5405� � 4 �4� 0�7��7�� 0� � 8 ��6540��� 5� 4 � �:� :� 40�09� � ���� 8 �4�5407�� 5 �-05�� � �'0��7��� 0�� ���d��� ( 6 �� 0���7�407��1�; � :� � ��650��� 0�864 � �0<��1�4� �� 5 �-05�� �� :� 40�09� � ���� ��?� �1 0��� 0�5 �� 0��� ;0��� ���� 4 �� �-��80�5���:� ���������� 4��?��864� 0��8��5�� 4���� 6 �� 6 4�0��?��� 05��8 ��6540��� ���6-����4���������b���� ( ��'; 4�-��:�#05����4�� 0:05�40����'#�����::� �����88� 46�04;�4��0-8 �7��:���� �56 04;�4 �6� � 0�5 �� ��� 05��8 ��6540704;�?;�5 ���0���4 ��-�����-��4��:�8���4 �� �0���1�4� ������64 0��4 �1 0��� ��650��� �@4� ���� 0�864 � �0<�� :� 40�09� � ���� � ?050�� � ��� <���� �� ����g� ( �<6 � �4� ����� ���eg� %8 �::�����3g�h� -�6�������e���( �� ; 4�-�8 �8� � � 4 ��6 ���:� 0������7� ;�;�6��� ����0�� � 104 � 10�� � 8�50���� 0�4� -044��4� 1�440��� ���� � ;0���� 6 �� �:� �� -�5 ��05��� 1���� � 1 05 � �� �� �� �4� � 4 �� �0��� ���� �� ��5��� �0�� � ���05� -�44� � �%8 �::� ���� /� �-�� ���e��� '#�� 0 � �� 4�5 �0i6��4 �4�0 ��� �4��:�8 �5405� ������� �4��:�8 0�508�� � �4 � �4 ���� ���j4�5 �����;�8�5<���k� �%8 �::���������'#��0 ���4���4�5 �����;��0<��4 �� �����:� 0� �;0���0���7� 0�40� �� ��0<����5 �-05��� :� 40�09� � � � 0� �54050���� �4� 0 � �� ; 4�-� :� � -����0��� 8���4 �� �0��� 1�4� � � � �64 0��4� 4���4 � � 0�� -646���;�?���:050���1�; �� 5 ��40��� ;�� �0� � ���6���0l���ee3���*04 �'#���-�����-��4�8 �5405� � 5��4 ��� � � -��0:;� 4 �� -05 ���70 ��-��4� �� 4 �4� �@0 40��� ����405� 8�4��40�� � 5��� ?�� -� �� :6��;� �@8 � ������� ���09����( ��-� 4��?70�6 ���7��4����: �-�'#���88�� �4��?��4 ��;0����0�5 �� ��0�� :� -� f�:0����104 �64���;���1� ��� �� �5 �-05�������-�5 ��05���0�864 ��'4��8��4���������������� 4 �4�0 � �8� 4���4��?��: �-�b�a�4�����a��%8 �::�����b���� (��0�5 �� ��i6��04;�;0�����:� 05��0���������� �04�0 ���5� � ;�4��0-8 �7���64 0��4�-�����-��4��:� 05�� :0�����. �8� �640�09�40����:� �0::� ��4� �6 5� ��:� �64 0��4 � 0�� 5��4�@4� �:� 5 �8� �0��8 ��6540704;� -6 4�?���@8�� ��� :� � 6 4�0�0��� 4 ��8 ��6540704;��( �� �6 5� ��:��64 0��4� :� �5 �8 �� ���64 0��4� � � 7��0�� �0���� ���05�����0�� ���05�:� 40�09� ��&�����:�4 �� �6 5� �� ��5�-8��4������4 � �:� ��� �������0 � 6::050��4�4�� 6 4�0�� �0��:� 40�04;�����8 ��6540704;��$�-?0��40����:�� ���05�����5 �-05��� :� 40�09� �0 �?�0��� 4 � �����1�����;���4�� 4�?�0 ���4 �4�4 ���88�05�40����:��0::� ��4�:� 40�09� ����� -��6 � � 0�:�6��5�� 4 �� 8 ; 05��� ���� 5 �-05��� 8 �8� 40� � �:� �0�� ���� �� ��5�� 4 �� ?0����05��� �5407040� ���88�05�40����:�?�4 �5 �-05�������� ���05�:� 40�09� � 0 ��������:� �4 ��0-8 �7�-��4��:� �0��8 ; 05���8 �8� 40� �����i605<� 688�;��:�� ��40���8���4��64 0��4 �:� � 0� � �;0����� �1����� �4�� <��8�4 �� �0��8 ; 05���8 �8� 40� �� �7� ;��=����4����������g�'0�� �����'0�� �����������5�6 ���:� 4 � ��7� 0�?��� 0�:� -�40��f ��?�64� 4 ���::�54��:�-��6 ��� 4�46 ����;0�����:��� �� 05�������4�0���� 46�;�1� � 6��� 4�<��� 4�� 0���40:05�40��� �:� '#�� �::�5407��� � 0�� � 8�54� �:� :� 40�09� �-�����-��4� ����;0����0�5 �� ��� � )�4� 0�� �)�4� 0�� �)�4� 0�� �)�4� 0�� ��������)�4 �� ���)�4 �� ���)�4 �� ���)�4 �� ���� � ( �� �@8� 0-��4�1� � 5���654��� 4�� 46�;� 4 �� �840-6-� :� 40�09� � ����1�4� �-�����-��4� 0�� '#�� 5��5�84�:� ��840-6-�;0����0�� 05���6 0���4 ��8� 0���: �-� �5�-?� �������4��)�;��������4�4 �� �� ���-;� :0����� ' � ���������� �� 056�46 ��� %�07� 04;�� �<�������� �������� �� ( �� �0�� ?����� �4��(�=�����'� 0� �6��� ��� ���5����05���9�����:�( ��j)�� 686 �( �54k����2�����( �� �0���:�4 �� 04��?����� �4��4 ������ ��� �0��4;8���' ����1�#���� �1��(� �5��'�0� �6��� �(�=����� '� 0� ��(�8� �0� �1� ��5��;����-�0��4�@46 �����07��� �;�104 �5�--���:0���4��-��06-��0 40�54��� <� ;����10 � ? �1�� -�44�� �� '�0�� 8+� ������ : �-� d���d�b� ���� ��� � ���05� -�44� � ���ea�� ( �� �@8� 0-��4� 1� � ��0�� �64� 0�� �� 8�04�8��4� �� 0��� 104 � 4 ��� �8�05�40�� � �70��� 41�� :�54� � 0���� "�54� ����( ���4;8���:�1�4� � ��0-��709��*�m�*�4� ��������( ����7����:�1�4� �0����5 �8�4�1� � -�0�4�0�����4��?�64�b�5-��?�7��4 �� �0�� 6 :�5��4 �6� �64�4 ��� �10���8� 0����:�4 ��5 �8�6�40�� ��� � -�46 04;�� � 0��40��� 1� � 5 ��6���� �4� �� ��;� 0�4� 7�� � 4� 40��� �� ��; � �:4� � 4 �� 8���40��� � �(���.��4 �1� ���i6088���104 �� �0�����0 0��40��� ; 4�-�:� �5��40�6�6 �:�����0 0��40����68�4�� b�d�5-���84 �� 4 �6� �64� 4 �� 05��� �10��� �� ������*�m�'�46 �4��� �1�4� �1� � �88�0��� =6 4� 4�� 3� �0�����:��� ��#05��%��� �'; 4�-��:�#05����4�� 0:05�40���� �46 �4��4 �� �0���104 �64�:������4 �6� �64�4 ��� �10���8� 0����:�4 ��5 �8��"� �-�0�4�0�0���:0���� 5�8�504;�� 8� 0��05� 0 0��40��� 1� � �88�0��� 4�� -�0�4�0�� 4 �� �0�� �4� �?�64� :0���� 5�8�504;� : �-� 4 �� 8���40��� 4�� -�46 04;�� .��4 � 1� �� 1�4� ��� �7� ;� ��;� 0�� 4 �� -� �0��� ?;� 8 0�<�0������ *3m� ��4� ��4��1�4������ ;����4� ��4��1�4������ ;���* ��0 ���1�4� �-�����-��4� ; 4�-�1 � �� 05�� :0��� �� ����4�<�84�5��40�6�6 �;� 6?-� ����?64�� ������1���4��� ;� 0�4� -044��4�;��6 0���4 �� 05�� � �10��� 4����� ��4� -044��4� 0 0��40��� 1� � 5 ��6���� �4� ��� ��;� 0�4� 7�� � 4� 40��� �� ��; � �:4� � 4 �� 8���40��� � �(�� 68� 4��-�46 04;��*�4� � ��7���1� �-�0�4�0���� �?�64� b� 5-� �?�7�� �6 0��� 4 �� 1�440���8� 0����*�4� ���7���1� �� 0���0�� 65 �����7���4 �4� �0 �0���5 �5< �1� ����7���8�0��4 ��:0����� ���� "�54� ���� 0@� 4;8�� �:� :� 40�09� � -�����-��4� 709�� "�m� $�1�6��� ���a� �( �� ���54��� 8��4 � 1� ���88�0���104 �������<�� ����5�1�6����( ����40 ���-�6�4��:�5�1��6���1� ��88�0���� �?� ��� �� ���4�:0���� �����8 �8� �40������"�m�$�-8� 4����a��( ��������<�� ����5�-8� 4�1� ��88�0��� 4��4 �� ���54���8��4 ��( ����40 ���-�6�4��:�5�-8� 4�1� ��� ���88�0���� �?� ����� ���4�:0��������� 8 �8� �40������"3m�$ �-05���:� 40�09� ����a��( ���@8� 0-��4���8��4 �1� ��:� 40�09���104 ��eb��eb�� db������������<�� ����% ����('.��)!.��,;8 6-����� 90�5� 6�8 �4��� � 8�5407��;��( �� ��40 �� �-�6�4 ��:�4 08��� 68� �8 � 8 �4���-6 0�4���:�8�4� ���;8 6-�����90�5� 6�8 �4��1� ���88�0���� � ?� ��� �� �� �4� :0���� ����� 8 �8� �40���� % ��� 1� � 4�8�� � ��� 0�� :�6 � �i6��� 0� 4���-��4 �� "0 4� 0� 4���-��4�1� �������:4� � ����0��� �5�7� ;�����4 �� � 4�4 ���0� 4���-��4 �1� ��������4������; � 0�4� 7������"�m�$ �-05���:� 40�09� �b�a�c�5�1�6����ba�c�5�-8� 4��ba��"bm�$ �-05���:� 40�09� � b�a�c�5�1�6���b�a��"dm�$ �-05���:� 40�09� �b�a�c�5�-8� 4�b�a���##��� ���b�1� �6 ���� � 8���4�-�4� 0����'��� �1� �� �1��0��4 ��8� 4�?���4 �; ���� �5�-?� �����������( �������; ����� ����0�� �1� ��68 ��4���: �-�4 ��4 �; �����4 �� 8���4���������6� ;�����������( ��4 �; �1� �� ? �6� 4� 4�� 4 ��-�0�� :0�������� ����0�� �1� ��8���4��� 0�� 4 ��8 �8� ���8��4� =6 4��:4� �68 ��40���� ( �� 8�50���1� �-�0�4�0����8���4�4��8���4�3��5-����� �1�4�� �1�3��5-�� �4�����;0�����44 0?64� � 1� ���4� -0���� : �-� ����-�;� ���54��� :07�� 0�� ��:� ��5 �8��4� ����� �0�� ���� 4 �1�;0��� �1� �� �5� ����: �-�4 ��0��� � �1 ����70���?� �� ��0�� ��4� � 7� 4� 4�����d�-��� �� �5 �8��:���5 �8��4� 1� �� �8� �4��;� � 7� 4����?6�������4����������4 ���? �6� 4�4��4 ��4 � 0���:��� �:� � �5� �0��� � �0������ 4 �1�;0�����( � 0���1� ������6 0���8�����4 � � ��( ��� �0� �1� ��5����������� 6�� � 0���4����-�0 46 ��5��4��4��:���a��'4 �1�1� ��� �� 6��� 0���8 �8� �;��"0����;�� �0������ 4 �1� ;0��� �1� ����4� -0��������5��7� 4���4��4��� ���������4 ��5����54�����4��1� ������;9���:����10��� 4 ������; 0 ��:�7� 0��5�� ��&!h���4�5 �0i6��6 0��� �##�'(�(�8�5<��������4 ��-�����0::� ��5�� 1� ����=6 4���?;��' �4�5 �0i6���,�-�9�����,�-�9���e����� � #� 6�4 ����� 0 56 0��#� 6�4 ����� 0 56 0��#� 6�4 ����� 0 56 0��#� 6�4 ����� 0 56 0������ � ( ���6-?� ��:��::�5407��40��� � 0������:0������ �0� �8��05������������ �0��1�0� 4����� � 7� 4�0���@� 1� ����4� 0��0:05��4�;� 0�:�6��5���?;�1�4� � ��0-���( ���6-� 05���-�@0-6-��6-?� ��:��::�5407�� 40��� � 0����� �3��b���1� � �07��� ?;�*�� 5���040���� :0����� � �0� �8��05����� ��b�d��� 0��*�� 5���040���� ������ �0� �1�0� 4�����d3���0��*������ � 7� 4�0���@���d��da��0��*��5���040����(�?�������'4��8� ����b��:�6��� 0� � � � 7� 4�0���@�0��'#��5�-8� 0���4 ��5��7��40�����-�4 ����4 �6� ���� 0 ��� ����3�� :�6�������0::� ��5�� :� � 4 �� �-���( ��4�4����6-?� ��:�� �0� �8��05�����1� � 0��0:05��4�;� 0�:�6��5���?;�1�4� � ��0-���( �� 0� � 4��6-?� ��:�� �0� �8��05����� �ed�����1� ��?4�0���� : �-� *�� 5���040��� 4�40 405���;� 0-0�� � 104 �*�� 5���040��� ���� 4 �� ��1� 4� �6-?� � �:� � �0� � 8��05����� ����e��� 1� � �?4�0���� : �-�*3� 5���040���� ( 0 � � 6�4� 1� � 0-0�� � 104 � ��6-���� �4� ���� ����b���� ( �� 0� � 4� � �0�� ;0���� �b���� 4� �����1� � �?4�0���� : �-� 4 ��*�� 5���040��� 4 �4�1� � 4�40 405���;� 0-0�� � 104 �*�� 5���040��� ���� 4 �� ��1� 4� ���3d� 4� ����� 1� � : �-�*3� 5���040���� ��6-��� ���� (6����������� 6��� 4���4 �4�4 � ��0 ��� ��6540���0��4 ��� �0��;0����0����4� ��4��1�440�������� ;0��� 1 ���5�-8� ���104 � 05��� �1��104 � 4���0���1�4� ��( �� 0� � 4� 4 �1�;0���� �d����4� �����1� � �?4�0���� : �-� 4 ��*�� 5���040��� 4 �4�1� � 4�40 405���;� 0-0�� �104 �*�� 5���040��� ���� 4 �� ��1� 4� �� #� -����4����� �b����4� �����1� �: �-�*3�5���040����( �� 0� � 4�?0����05���;0�����������4� �����1� �:�6���: �-� *��5���040�������4 ����1� 4�?0����05���;0�����e�be�4� �����1� �:�6���: �-�*3�5���040���� � (�?��� ��� ��:�6��5�� �:� 1�4� � ��0-�� ��� �0::� ��4� ;0���� 5��4 0?640��� 5 � �54� � �:� �� �� 05�� 4 �� 8���4���0��'#�� ( ��4-��4 � �::�5407�� 40��� ����� 0����� (�4��� � �0� � 8��05����� �&���� "0����� � �0� � 8��05����� �&���� ������ � �0�� 1�0� 4� ���� , �0�� ;0���� �4� ����� '4 �1� ;0���� �4� ����� �0����05��� ;0���� �4� ����� +� 7� 4� 0���@� �a�� *�� �d�e�� ed����� �b�d�� ���b�� b����� d����� ������� �d���� *�� 3��b�� eb����� ������ ���d3� b�de�� d�db�� ���33�� �d��d� *3� ������ ���e�?� ����d� ������ ��3d?� b���?� e�be?� �b�bb� �' ����b�� &'� �����d� &'� &'� ��3�3� ���b�� ����e� &'� $h��a�� �d���� ���be� d���� b�3d� ���d� ��e�� ����� ����� *��m�*�4� ��������*��m�'�46 �4����*3�m���4� ��4��1�4������ ;�����&'m�&�4�'0��0:05��4�� � )��6 ��� 4�46 � 0��0:05��4�;�0�:�6��5���4 ���6-?� ��:��::�5407��40��� � 0������( �� 0� � 4��6-?� ��:� �::�5407�� 40��� � 0����� �33����� 1� � �?4�0���� : �-� "��1 05 � 1� � 4�40 405���;� 0-0�� � 104 � "��� ( �� ��1� 4��::�5407��40��� � 0�������b�����1� ��?4�0����: �-�"d�4 �4�1� � 4�40 405���;� 0-0�� �104 �"3����� "b��+� �����4����� �������5���654�������@8� 0-��4�4���7��6�4��4 ���::05�5;��:��0::� ��4�� ���05� -��6 ������0�� ���05�:� 40�09� ����� �5� ����-�@0-6-��6-?� ��:��::�5407��40��� � 0�����: �-�4 �� 4 ��4-��4� �:� ��a� &./'� c� ���� 4� -��6 �� ����� ( �� 0� � 4� �6-?� � �:� 4�4��� � �0� � 8��05����� �����e���1� ��?4�0����: �-�"3�����4 ����1� 4��6-?� ��:�� �0� �8��05�������d�����1� � �5� ���� : �-�"��4 �4�1� � 0-0�� �4��"���( �� 0� � 4��6-?� ��:�:0������ �0� �8��05�������������1� ��?4�0���� : �-�"��4 �4� 0-0�� �4��4 ��"3�����"������4 ����1� 4��6-?� ��:�:0������ �0� �8��05������db�b���1� � �?4�0���� : �-� "b� �(�?��� ���� �� 6�0�� ����b�� �8� 4��� 4 �4� : �i6��4� 5�-?0���� �88�05�40��� �:� 5�1�6��� 8�6 � 0�� ���05� :� 40�09� � �4� � 0�5 �� ��� 8 ��6540��� : �-� 655� 07�� :0����� � �0� ����� 8��05������( � ��1� ���� 0��0:05��4��::�54��-����4 ���0::� ��4�-��6 ��� 4�46 �0�� � 8�54��:�1�0� 4� �:������� �0� �4 �6� �4 ���6-� 05���;�-�@0-6-������� �0� �1�0� 4� �����3���1� ��? � 7����4� "�� ���� 4 �� -0�0-6-� �������� 0�� "3�� )��6 ��� 4�46 � � � 0��0:05��4� �::�54� ��� � �0�� ;0����� "�� 8 ��65��� 0��0:05��4�;�4 �� 0� � 4�� �0��;0�����b����4� �����4 �4�1� � 4�40 405���;� 0-0�� �4��"3��( �� ��1� 4� ������ 4� ������ �0��;0����1� � : �-�"�� 4 �4�1� � 0-0�� �104 �"������ � � ����3���� �0� � 4�4��� 4 �4� �0� �104 � 0� �:� 40�04;�0�:�6��5��4 ��� �0��;0������ � (�?��� ��� ��:�6��5�� �:� -��6 ��� 4�46 � ��� �0::� ��4� ;0���� 5��4 0?640��� 5 � �54� � �:� �� �� 05�� 4 �� 8���4���0��'#�� ( ��4-��4 � �::�5407�� 40��� ����� 0����� (�4��� � �0� � 8��05����� �&���� "0����� � �0� � 8��05����� �&���� ������ � �0�� 1�0� 4� ���� , �0�� ;0���� �4� ����� '4 �1� ;0���� �4� ����� �0����05��� ;0���� �4� ����� +� 7� 4� 0���@� �a�� "�� 3�����?� �����5� ������� ������ ����5� b��35� ����35� �d����?� "�� 33����� �d���?5� �����?5� ����3� ����5� b��35� ����d5� �d�3��?� "3� �d���5�� ����e��� ������?5� ������ b����� d����� ���bd�� �b�e��?� "� �e�e�?5� eb��3?� �e����?� ���b�� b����� d�d��?� ������� �d����� "b� �b����� e����?� db�b�5� ���3�� b�3d?� d��d?� ���d�?� �d����?� "d� �b����� �e�e�?� dd�e35� ���b3� b���?� d�dd�?� �����?� ����d?� �' ����b�� 3�bd3� e�3e�� �����e� &'� ��3bb� ���d3� ��b��� ��be�� $h��a�� �3���� ���d�� �d���� 3���� ����� ����� b��3� b���� "��m�$�1�6��� ����a��� "��m�$�-8� 4� ����a��� "3�m�$ �-05��� :� 40�09� � ����a��� "��m�$ �-05��� :� 40�09� � �b�a��c� $�1�6�����ba��c�$�-8� 4���ba���"b�m�$ �-05���:� 40�09� ��b�a��c�$�1�6����b�a���"d�m�$ �-05���:� 40�09� ��b�a��c� 5�-8� 4��b�a������&'m�&�4� 0��0:05��4� b� �0�����:��� ��#05��%��� �'; 4�-��:�#05����4�� 0:05�40���� � � ����3�� :�6��� 4 �4� ;0�����:� ?� �� 05��1� � 0��0:05��4�;� 0�:�6��5���?;�� ���05�-�44� �� 5�40��� �@5 ����� 5�8�504;�� �04 ������8 � 8 � 6 � ����8�4� 06-��( �� 0� � 4� 4 �1�;0���� �d���� 4� ����� 1� ��?4�0����: �-�"3�4 �4�1� � 0-0�� �104 �"������"d��( ��8 �?�?��� �� �� ��:�0�5 �� ��� 4 �1� ;0���� 0�� 4 ��"3�-0� 4�?���6�� 4�� 0� � � 4�4����6-?� ��:� 40��� �-������� 4���� �8���4 ��( �� ��1� 4� 4 �1�;0�����b��3�4� �����1� ��?4�0����: �-�"������"���+� �0������ �?�����3��1� �:�6�����1� 4� 4 �1� ;0���� 0�� 5��7��40�����-�4 ��� 4 ��� '#�� :� � �##�� � ��3�� 7� 0�4;�� ( �� 0� � 4� ?0����05��� ;0���� ����bd� 4� ����� 1� � :�6��� : �-� "3�1 05 �1� � 0-0�� � 104 � "��� ( �� ��1� 4� ?0����05��� ;0���� �����3�4� �����1� �:�6���: �-�"��4 �4�1� � 4�40 405���;� 0-0�� �104 �"���( �� 0� � 4� � 7� 4�0���@� ��d���a��1� �:�6���: �-�5 �-05���"��4 �4�1� � 0-0�� �104 ������4 � �4 ��4-��4 �����4 ����1� 4� �����da��1� �: �-�"d���� ( ���6-?� ��:��::�5407��40��� � 0�����1� � 0��0:05��4�;�0�:�6��5���?;�4 ��0�4� �540����::�54��:�1�4� � ��0-������-��6 ��� 4�46 ��( ��-�@0-6-��6-?� ��:��::�5407��40��� � 0�������������1� ��?4�0���� : �-�*�"�� 1 05 � 1� � 0-0�� � 104 � *�"��� *�"��� *�"��� *�"b�� *�"d�� *3"�� ���� *3"��� ( �� ��1� 4��6-?� ��:��::�5407��40��� � 0���������b3��1� ��?4�0����: �-�*�"d��(�?���3��� ���� (�?��� 3�� ��4� �540��� �::�54� �:� 1�4� � ��0-�� ���� -��6 ��� 4�46 � ��� �0::� ��4� ;0���� 5��4 0?640��� 5 � �54� ��:��� �� 05��4 �� 8���4���0��'#�� ( ��4-��4 � �::�5407�� 40��� ����� 0����� (�4���� �0� � 8��05����� �&���� "0����� � �0� � 8��05����� �&���� ������ � �0�� 1�0� 4� ���� , �0�� ;0���� �4� ����� '4 �1� ;0���� �4� ����� �0����05��� ;0���� �4� ����� +� 7� 4� 0���@� �a�� *�"�� 3�������� ed�b3?��� ������� ����3�?� b������ d��b5��� �����5��� ������� *�"�� 3��d��� e3���?��� dd���?5� ������?� ��ee:� � b�db�� � ���d��� � �d��e�� *�"3� �b������� ��b�d��� ���d���5� ����3�?� d��e�� d��3?��� ����3?5� �d��e�� *�"�� ��������� ��3�����5� �b�d��?� ���b��?� d���5�� ���d��5� �3���?5� �b�be�� *�"b� �����:�� eb�e3?�:� d����?5� ����3�?� d��d��5� d���?��� �3���?� ������� *�"d ���b3�� �d��� 0� db�e3?5� ������?� b������� ��b3�?� ����3?5� ���eb�� *�"�� �����?��� �e���:�0� ����3�?� ���b��?� ��de��0� b�d�:� � ���b�:� � �d�e��� *�"�� 33�b3�?� �����5� � �3�e3��5� ������� ��ee:� � b��3�: � ���e����� ���d��� *�"3� �����?��� ����b3�?� ���b3��5� ���d��?� d���?��� ���3�?� �3�d3�?� �b��d�� *�"�� 33�33�?� ����d���5� �b�33�?� ����3�?� d����?� ������ ���b3�� �d��b�� *�"b� 3�������� ���b35� � d������5� ������?� b���5��� d�3e5�:� ���d���� ������?� *�"d� �e������� �������?� d����?5� ����3�?� b���5��� ������5� �����?5� �b�3b�?� *3"� 3������5� d3��30� �3�d��?� ������?� 3���<� ����0� ��d3=� ������?� *3"�� 3��e3�?� ���d���0� �������5� ���b3�?� 3�eb=<� ��e� 0� ��e�0� ���d��?� *3"3� �b������� ee���?��� ���d���5� �����?� b�bb��:� d��3��:� �������� �b��e�� *3"�� �����?�:� ���33�� � d��d���5� ����3�?� ����0=� b��b� � e��3 0� ���e��� *3"b� ��������� ���b35� � d����5� ����3�?� ���b �=� b�be:� � ������ � ���d3�?� *3"d� �d���5��� ��������� d����?5� ���3��?� ��d���=� b��b:� � ����3� � �b����� �' ����b�� d����� �d��d�� �e��ee� ���3e� ��d�b� ����3� ������ ���e�� $h��a�� ���e�� ���d�� �d���� 3���� ����� ����� b��3� b���� *��m�*�4� ��������*��m�'�46 �4����*3�m���4� ��4��1�4������ ;��"��m�$�1�6�������a���"��m�$�-8� 4�����a���"3�m�$ �-05���:� 40�09� � ����a���"��m�$ �-05���:� 40�09� ��b�a��c�$�1�6�����ba��c�$�-8� 4���ba���"b�m�$ �-05���:� 40�09� ��b�a��c�$�1�6����b�a������"d�m� $ �-05���:� 40�09� ��b�a��c�5�-8� 4��b�a�� � ( �� 0� � 4����b�d����6-?� ��:�� �0� �8��05�����1� ��?4�0����: �-�*�"3� 4�40 405���;� 0-0�� �104 � *�"���*�"3��*�"������*�"d��( ����1� 4��d3��3���6-?� ��:�� �0� �8��05�����1� ��?4�0����: �-� *3"��1 05 �1� � 0-0�� �104 �*�"d��*�"������*3"���( �� 0� � 4��6-?� ��:�:0������ �0� �8��05��� �� �������� 1� � �?4�0���� : �-� 4 �� *�"�� :����1��� ?;� *�"3�� *�"��� *�"��� *�"��� *�"3�� *�"��� *�"b��*3"���*3"���*3"3�����*3"���( �� ��1� 4��6-?� ��:� :0������ �0� �8��05����� �d������1� � �?4�0���� : �-�*3"b�� ( �� 0� � 4� 1�0� 4� �:� ������ �0� � ������� ��� 1� � �?4�0���� : �-�*�"�� d� #� -����4����� 1 05 � 1� � 0-0�� � 104 � ���� �4 � � 0�4� �540��� �::�54� �:� 1�4� � ��0-�� ����-��6 ��� 4�46 � �@5�84� *3"3��( ����1� 4�1�0� 4��:������� �0� �����������1� ��?4�0����: �-�*3"3�1 05 �1� � 0-0�� �4�� 4 �� ���� �4 � � 0�4� �540��� �::�54� �:�1�4� � ��0-�� ����-��6 ��� 4�46 � �@5�84�*�"��� ( �� 0� � 4� � �0�� ;0���� 1� � �? � 7��� 0��*�"�� �d���� 4� ����� 1 05 � 1� � 0-0�� � 104 �*�"3� ����*�"b����� ( �� ��1� 4�;0�����3����4� �����1� ��? � 7���0��*3"��4 �4� 0-0�� �104 �*3"���( �� 0� � 4� 4 �1�;0���� �����4� �����1� � �5� ����0��*�"�� 0-0�� �104 �*�"���*�"d��*�"3�����*�"d��( ����1� 4� 4 �1� ;0���� ������4� �����1� �:�6��� 0��*3"��1 05 �1� � 4�40 405���;� 0���405���104 �*3"����<?� � ������� :�6��� 0� � 4� 4 �1� ;0���� 0�� 4 �� 5�-?0��40��� �:� 0�? ��� 7� 0�4;� ���� �b� ��;� ���� ����0�� �� ( �� 0� � 4� ?0����05��� ;0���� ����b3� 4� ����� 1� � �5� ���� 0�� *�"�� 0-0�� � 104 � *�"3�� ( �� ��1� 4� ?0����05��� ;0���� ���d3� 4� ����� 1� � :�6��� 0�� *3"��� ��6-��� ���� (�6��� ������� :�6��� 0� � 4� ?0����05��� ;0���� 0�� 5�-?0��40��� �:� 4 �� 5 �-05��� :� 40�09� � ���� �46 �4��� 5���040���� ( �� 0� � 4� � 7� 4� 0���@�������a��1� � �5� ����0��*�"b�4 �4�:����1���?;������4 � �4 ��4-��4 ��( ����1� 4� � 7� 4�0���@�����d�a��1� �:�6���0��*3"��� � $��5�6 0��$��5�6 0��$��5�6 0��$��5�6 0������ ���� �� ������4 �� � 6�4 ��:�4 ��8 � ��4� 46�;�04�5���?��5��5�6����4 �4�4 �� 0� � 4�;0����1� ��? � 7��� 0�� 1�4� ������� 5���040��� ���� 4 �4� 1� � 4�40 405���;� 0-0�� � 104 � �46 �4��� 5���040���� ( �� 5 �8 � 104 �5 �-05��� :� 40�09� �b�a�c�5�1��6����ba�c�5�-8� 4��ba� �1���4 �� 0� � �;0���� 4 �4� 0 � 0-0�� �4��5 �-05���:� 40�09� ����a�?64�-� ��: 0����;�:� �4 ����70 ��-��4�4 ���5 �-05���:� 40�09� � ���a�� � �5<��1�����-��4�5<��1�����-��4�5<��1�����-��4�5<��1�����-��4���� ���� ( �� �64 � � � �� � �4�:6�� 4�� 4 �� �������� ��5���-;� �:� '50��5� � :� � 4 �� :0���50��� 688� 4� 4�� 5���654�4 �� 46�;�� ���� #�:� ��5� #�:� ��5� #�:� ��5� #�:� ��5� ���� � �<?� ��)��/�� ������#� 8�� �� �:� ;? 0�� ���� 0�? ��� 05�� 7� 0�40� � 4�� �0::� ��4� ����0�� � ��� � 6��� � ; 4�-��:� 05�� 0�4�� 0:05�40��� 0��4 �� 8���4��-��� �� ����)��'��( � 0 �� �84���� �������%�� );-�� 0�� �� �� 0 ����������3��&64 0��4�6 ���::050��5;������64 0��4�684�<��0��5��7��40���������0�4�� 07���'#��� 05�� 56�407�40��� ; 4�� 0��)����� 5� ��&�� � :0���� � �:4� �:�)� 4� n � 4 � 0 �� �8� 4-��4� �:�$ �8� ���� '�0�� '50��5� �� $� ����� %�07� 04;�� �4 �5��� &��� o 448�pp500:���5� �������6p 0p4 � � p-���=���04 � 0 �8�:q�� �� 6�0���)��&�����b����:�6��5���:�0�� ���05�:� 40�09� �����5�1�6������4 ��� �14 �;0��������i6��04;��:� �0��� ���b�� )'� ( � 0 �� �8� 4-��4� �:� �� 056�46 ��� $ �-0 4 ;�� �������� � �� 056�46 ��� %�07� 04;��);-�� 0�� �� �� <���� �� �� ������ '#��� 4 �� '; 4�-� �:� #05�� ��4�� 0:05�40���� �� � 5��� ?�� -� ��� �$+!� �7���8�� &�4� ����������� ��6-�����������'��.��������#��$� 4����������#��)��h0 8� � �����b���0��������1�4� �6 ���:�0 0��4��� 4 �805����� �?05� 05�� ; 4���� 05��*�4� �)�������������b�� ��6-����������)������(��.��(�6����������"0����*�4� �)�����-��4�4��'�7��*�4� �����0�5 �� ��04 � 8 ��6540704;�0��0 0��4��� 05����� 05��*�4� �)������e�����3��� �� �0�����:��� ��#05��%��� �'; 4�-��:�#05����4�� 0:05�40���� � ��������3��h� 0:05�40������� �:0��-��4��:� 4 ��'; 4�-��:�#05�� ��4�� 0:05�40��� 0�� ���54���� �� ��:� �������� �� ( 0��� )��04� 0��� #�8� 4�� '��"� �7���8-��4� , �68�� o 448�pp500:���5� �������6p 0p5�6�4 0� p?������� p?���8�4: �8�8�:q�� �7� ;��=���� ,�� +��� ,�� +�� +�� �0�� ���� ��� ��<90���� ������ �::�54� �:� -6�0508��� 5�-8� 4� 0�� 5�-?0��40���104 �5 �-05��� :� 40�09� �����-��6 ������ �14 �����;0�����:�1 ��4���� 0���'50�� (�5 ��������������������� �;��)��)���)��&��)0� ������������)6 4�:0� ����)��+� �0����eed��#05��8 ��6540��� 5�� 4 �0�4 � 0�� �������� �� �-8�05�40��� :� � :6 4 � � � �� 5 � 8 0� 040� �� ���� #05�� #� �� 5 � 0��� 0��� . �� � � ����. 0� 040� ��$�����4� ��40����������##��. 0��080�� �� "��� 0���&��/���������0����8 ; 0����;��:� 05������.���4��&64 ��3�����3���e�� "�!� �"���� ������ 056�46 ��! ���09�40����� ������*� ��� :���� 046�40���� 4 �� "�!� :���� 8 05�� 0���@�� o111�:���� �p1� ��:��� 046�40��p��pd�eq�� ,�-�9�� /�� ��� ���� ��� ��� ,�-�9�� �e���� '4�40 405��� . �5��6 � � :� � �� 056�46 ��� #� �� 5 �� ���� ����� �� ��*0��;�����'�� ��&�1��� <��$ 05 � 4� ��� 0 ?�����(� ��4���'0���8� ��8�d���� , ���:0�����'��)������&��,�� �1�0�����ee�����4 ��6540�������!7� 70�1������'6 4�0��?0�04;��:�#05��0�� 4 ��,��?���"����'; 4�-��&��,�� �1�0����'��)��, ���:0��������/��'��"0 � ����� ���� +� �����)���������(��)���' �6��� ������/��.�6���)��'������ 60;����������'��)��2�?�� �������� �::05�5;��:��0::� ��4�� ���05�-��6 � �����0�� ���05�:� 40�09� ����4 ��;0��������;0�����44 0?64� � �:�?� �� 05���( ���� 056�46 0 4 ��e��r����������b�� +� �0���)������%��/�� �?�����3���0?� ��09�40����:� 05�� �54� ��$����������� �104 4���� ��0����� 5�-8�4040��s� .� 4� � 8�8� � 8 � ��4��� �4� .�(##�� 5�--6�05�40��� :�0 � ���3� ���� �4� �4��� ' � �4���� �<������6���������� +� �0���)��2��������.� :� -��5���:��##��� ��3��0��4 ��'#������5��7��40�����-�4 �� �����4 �0 � 4�5 �����;�-0@� ��)��'��( � 0 �� �84���:��� �������%��);-�� 0�� ��88�������� ��6���0��� +�� �ee3�� ��� ; 4�-�� ��� 09056�46 �� 0�4�� 07��-����5 ��� ( �8056�46 �� �� 6 �� ��� ���� ���� ������ )0 ���������e��'; 4�-��:� 05�� 0�4�� 0:05�40��� �'#������i6� 4� :� � 0�4� �5407�� 50��5�� 4��-040��4�� 4 �� 5�0-�4�� 5 ����� 76��� �?0�04;�� � 0��� �� 40464�� �:� (�5 �����;�� �� 056�46 ��� ; 4�� ���� ���0��� 0��g�'5 �����:���70 ��-��4������<�<��( �0������ �!.�$��:��'� 0� ���� 4 ���70 ���� '50��d�������������� '0��7��� 0�� .�� ���d�� ( ��040����� ���� '#�� -�4 �� � �:� 8���;� 56�407�40���� �� 5�-8� �407�� �5���-05� ����; 0 �� )� 4� � �:� '50��5�� 4 � 0 � 6?-044��� 4�� 4 �� %�07� 04;� �:� �� 056�46 ��� '50��5� �� �8� 4-��4��:��� 056�46 ����5���-05 �� � 1���b����b�� '0�� ��$��.���������'��'��'0�� ��������'46�0� ����4 ��� �14 �����;0����8� �-�4� ��:�1 ��4��( 04056-� �� 4076-�����4��6 ������� �6����?� ���5�-8� 4��88�05�40����)�� � ��� 0��������������������� ����� '4��8��*������&��%8 �::��������/� �-���������� �70�1��:��� 056�46 ��� � �� 5 �0 6� � �0 ���?;�4 �� '; 4�-��:�#05�� ��4�� 0:05�40��� �'#��� : �-�)����� 5� ��!88� 46�040� � :� � 0-8 �70��� :� -0��� ; 4��:� � � �6 5��8�� �:� -� ���� 0���'; �����3�����e������� '4��8��*��������b��( ��'; 4�-��:�#05����4�� 0:05�40����'#����#� 6�4 �: �-��@8�� �4� ;�:0���� � �� 5 � 0���7� ;�$�� 4��#� �� 5 ����� �����8 � 8�54 �:� ����84�40���4���07� ��8 ��6540��� ; 4���:� � �6 5��8�� �:� -� ��*� 4��: 05���#05�� �7���8-��4�� �50�40����*�# ��������.��bb��� ��6�<l���7� ;�$�� 4��o 448�pp500:���5� �������6p 0p 4��81� ���b�8�:q�� �� #� -����4����� ( �<6 �� ��� /��� '�� #�4 �� �� %�� .�40�� ���� ��� /6-� �� ������ �::�54 � ��� 05�� 8���4� -� 8 ����;� ���� 8 ; 0����;� �:� 1�4� � ���� � �50�4��� -�����-��4� 8 �5405� � �:� 4 �� '; 4�-� �:� #05�� ��4�� 0:05�40��� �'#������� 4 �0 � 0-8�05�40�� � :� �5 �8�8� :� -��5���.���;�*�4� ���7��e���3t ���� ( �<6 �����/���&��%8 �::����������4��;�����e������ � -��4��:�8 ; 0����05����::�54 ��:�'; 4�-��:� #05����4�� 0:05�40��� �'#���8 �5405� �5�-8� ���104 � �5�--������ 05��56�407�40���8 �5405� � 0�� ���0�������@84���� 05���d��������e��� %8 �::�� &�� ���3��+0� � � ;0��� � 104 � :�1� � �@4� ���� 0�864 s� ( �� ; 4�-� �:� 05�� 0�4�� 0:05�40��� ���� 8�4��40���5��4 0?640�� �4���� 056�46 ��� 6 4�0��?0�04;����4�������� 05��'6 4�����3��b��� %8 �::�� &�� ������ * �4� 0 � ?�0��� ��� ���� �?�64� ; 4�-� �:� 05�� 0�4�� 0:05�40��� 0�� 5 0��� ���� �4 � � 5�6�4 0� s��� ��5����05���.� 8�5407� �:� �'6 4�0��?��� �7���8-��4�'�-0�� �'� 0� ��$� ����� %�07� 04;���b�'�84��� %8 �::�� &�� ���b�� �� ��5����05���;� �6��� �� 056�46 ��� ; 4��� $��� 4 �;� 8 �70��� :� � 4 �� 1� ��f � � �10��� 8�86��40�� s� ( �� ���?��� :���� r� 8 ��654� 5 �0���;��-05 �� 0���7�40�� �� 5��:�054 �� 4 �4��0� �� �64 5 � � ( �8��4���� !54�� ����3�� +� �� �0-�� o111�4 �8��4�����p���bp� �? 4 �54 p�0�< p68 �::u �<?i�ii�8�:q�� %8 �::�� &�� ���� ��� /� �-�� ���e�� $� �� 46�;�� '; 4�-� �:� #05�� ��4�� 0:05�40��� �'#���� 0�� �� 056�46 ��� 4�5 �����0� � :� � ��7���80��� 5�6�4 0� �� "0���� �8� 4�� ����@� 3�� �6 �8���� (�5 �����;� � � -��4�, �68��/� � 6 ���,� -��;�� h� -�6����)�����e��)� ��: �-��� ��: �-��� �4��-� ���'5��0���68�� 0 �-0��40����:��� 05��56�407�40��� 4�5 �0i6���"� -0���)�44� ���4� :�� 4��4 ��&�4 � ���� ��8�3�� � � � microsoft word 11. baj-235_revised.docx bangladesh agron. j. 2016, 19(1): 87-97 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice sadia masrufa, anisur rahman, md. hasanuzzaman, taufika islam anee, md. hazrat ali and mirza hasanuzzaman* department of agronomy, faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author: mhzsauag@yahoo.com key words: seedling hardening, hybrid rice, seedling storage, transplanted rice abstract short term hardening before transplanting may enhance the defence mechanism of rice seedlings against any stress during their establishment and contribute d to enhanced growth and yield. thus, this study was conducted involving one local inbred (pajam), one popular high yielding (brri dhan53) and one hybrid (brri hybrid dhan4) rice variety. the experiment was laid out in randomized complete block design with two factors. seedlings were transplanted directly to the main field as a control treatment and/or subjected to four different hardenings like seedlings storage in shade, open field under sunlight, float in water and cold air in refrigerator before transplantation. hybrid variety out yielded both the local and inbred varieties due to their highest effective tillers, longer panicle length and 1000-grain weight. pre-hardening of seedlings in open field under sunlight conditions enhanced the yield attributes and ultimate yield of rice compare to others. the best combination was pre-hardening seedlings in open field conditions with hybrid cultivar regarding to the yield attributes and final yields. it is suggested that hybrid variety and prehardening of seedlings before transplantation to the main field could be increase the rice yield productions. introduction rice (oryza sativa l.) is extensively grown in all seasons of bangladesh viz., aus, aman and boro, which covers more than 78.16% of the total cultivated area (bbs, 2014). rice is grown under 11.385 million hectares of land with a production of 34.452 million tonnes, including aman alone in 5.53 million hectares but with a production of only 13.03 million tonnes (dae, 2014). proper planting and management practices are the most effective means for increasing yield of aman rice at farmer’s level using inbred and hybrid varieties (alauddin, 2004). though the yield of rice in bangladesh has generally increased, it is still much lower than the genetic potential yield. however, the genetic potentiality may not be achieved due to various environmental and socio-economic conditions. this unexpected environmental conditions cause serious damage to the rice seedlings in the nursery beds and in the freshly transplanted fields. in that case, uprooting them from nursery beds can be a possible solution but it may cause loss of the vigority of seedling. as a result, aman rice cannot meet the increasing demand in the market. crop damage due to early or late flood is very common in bangladesh. in flood prone areas, farmers cannot re-transplant the affected land due to unavailability of seedlings. in this case seedlings are often stored under different conditions. in many reports storage of seedlings under adverse condition showed higher vigority and yield performance under field condition. 88 rahman et al. seed and seedlings both undergo these conditions which are termed as priming and hardening, respectively. the underlying mechanism(s) how seedling hardening can enhance the growth and productivity of transplanted crops may be their cross-adaptation process. seedlings that undergone hardening increased their total sugar and α-amylase activity and exhibited earlier initiation of protein, rna, and dna synthetic activity. consequently, when the seedling is set for establishment, cellular events are much advanced (farooq et al. 2005). considering the above facts, it is hypothesized that the short-term adverse condition of seedling just before transplanting may induce the up regulation of defence mechanisms in plants which would be active during the subsequent episodes after transplantation to provide healthy plants with better productivity of rice seedlings. thus a detailed study with an inbred and a hybrid variety with some pre planting hardening of seedling treatment were undertaken to investigate the effect of seedling hardening on the performance of aman rice as well as to compare the relative performance of local, high yielding variety (hyv) and hybrid rice under different hardening treatment. materials and methods the field experiment was conducted at the agronomy field of sher-e-bangla agricultural university under the agro-ecological zone of modhupur tract, aez-28. geographically the experimental are is located at 2377n latitude and 9033e longitude at an altitude of 8.6 meter above sea level. the farm belongs to the shallow red brown terrace soils. the soils were clay loam in texture with ph 5.4 to5.6 and 0.82% organic carbon. seeds of three rice genotypes (oriza sativa l. cv. brri dhan53, brri hybriddhan4, and pajam) were obtained from bangladesh rice research institute, gazipur, bangladesh. seedlings were grown at raised seedbed for 25 days. seedlings were uprooted the seedbed and tied in bundle and kept in different place for pre-hardening according to the treatments before transplanting to the main field. seedlings were pre-hardened by the following treatments viz. t1 = direct transplanting (control), t2 = storage in shade (seedlings kept in shade for 48 h), t3 =storage in open field (seedlings placed at normal condition under sunlight for 48 h), t4 = storage in water (seedlings float in water for 48 h) and t5 =storage in cool air (seedlings kept in cold temperature at 4°c in refrigerator for 24 h). the experiment was laid out in randomized complete block design (rcbd) including two factors with three replications. a basal dose of fertilizer with p2o5, k2o, z and s was supplied in the form of triple super phosphate, murate of potash, zinc sulphate and gypsum. urea was top-dressed in three equal instalments at land preparation, 30, and 50 days after transplanting. two seedlings were transplanted in each hill maintain 25 × 15 cm on the well puddle experimental plots. intercultural operations were done whenever necessary. the yield contributing characters such as number of effective and non-effective tillers hill-1, number of grains panicle-1, panicle length and 1000-grain weight were recorded from plant samples. three square meters at center of each plot was harvested, dried, threshed and adjusted 12% moisture content to estimate the grain yield. harvest index was calculated by the following equation harvest index (%) = (grain yield/biological yield) × 100. 89 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice the recorded data were subjected to statistical analysis. analysis of variance was done following two factor split plot design with the help of computer package xlstat 2014 and mean separation done by lsd at 5% level of significance. results and discussion genotypic differences on yield contributing attributes and yield significant variation was found among the varieties regarding to the effective and noneffective tiller hill-1, panicle length, filled and unfilled grains panical-1, 1000-grain weight. according to the figure 1-6, brri hybriddhan4 produced significantly the highest effective tiller (12.07), lowest non-effective tiller (0.98), longer (26.23 cm) panicle, highest filled grain (129.50) and unfilled grain (334.25) and highest 1000-grain weight (25.19 g). in contrast, pajam produced the lowest effective tiller (6.48), highest non-effective tiller (2.54), shortest panicle length (22.77 cm), lowest unfilled grain (13.77), lowest 1000 grain weight (17.83 g) whereas lowest filled grain (90.19) from brri dhan53. grain yield, straw yield, biological yield and harvest index varied significantly in different varieties (figure 7-10). the highest grain yield (7.01 t ha-1) was recorded by brri hybriddhan4 which is 58 and 54% higher than brri dhan53 and pajam, respectively. straw yield was found in a sequence of brri hybriddhan4 > brri dhan53 > pajam. brri hybriddhan4 produced 42% more straw yield than pajam. hybrid variety brri hybriddhan4 produced twice total biological yield as much as pajam. d b a c b 0 2 4 6 8 10 12 direct transplanting storage in shed storage in open field storage in water storage in cool air n o. o f e ff ec ti ve ti lle rs h ill ꟷ1 fig.1. effect of variety, pre-hardening of seedlings and their interactions on effective tillers hill-1 of rice. data labelled with different letters are significantly different at p<0.05. 90 rahman et al. c a a b a 0.00 0.50 1.00 1.50 2.00 2.50 direct transplanting storage in shed storage in open field storage in water storage in cool air n o. o f e ff ec tiv e til le rs h ill ꟷ1 fig. 2. effect of variety, pre-hardening of seedlings and their interactions on non-effective tiller hill-1 of rice. data labelled with different case letters are significantly different at p<0.05. fig. 3 effect of variety, pre-hardening of seedlings and their interactions on panicle length of rice. data labelled with different letters are significantly different at p<0.05 influence of pre-hardening of seedling on yield attributes and yields 91 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice yield attributes were significantly influenced by the pre-planting hardening (figure 1-6). preplanting hardening under open air conditions influenced the yield attributes mostly than others compare to direct transplanting to field after uprooting the seedling from seedbed. the highest effective (9.81) and non-effective tiller (2.04), the longest panicle length (26.42 cm), the highest filled (125.48) and unfilled grain (26.06) and the highest 1000grain weight (23.38 g) were found from pre-planting hardening of seedling under open field storage conditions followed by storage in cool air conditions. direct transplanting of seedling after uprooting from seedbed influenced to produce lowest effective (7.32) and non-effective tiller (1.36), the shortest (21.12 cm) panicle length, the lowest filled and unfilled grain (94.86 and 18.73, respectively) and the lowest 1000grain weight (20.64 g) than other treatments. grain yield straw yield, biological yield and harvest index also influenced significantly by different pre-hardening treatments (figure 7-10). open field pre-hardening seedlings contributed to produce the highest grain yield (4.85 t ha-1) and straw yield (4.87 t ha-1) which is 20 and 18% higher than the direct transplanting after uprooting the seedlings from seedbed. the highest biological yield (9.72 t ha-1) was obtained from the storage in open field seedlings. open field seedlings produced the highest grain yield and straw yield which resulted in the highest biological yield. the highest harvest index (50.32%) was obtained from the condition of storage in cool air seedling which was statistically at par with storage in water (49.45 %) and storage in open air condition. the lowest harvest index (47.53%) was found from direct transplanting seedlings which were statistically similar with storage in shading condition (47.80%). fig.4. effect of variety, pre-hardening of seedlings and their interactions on filled grain panicle-1 of rice. data labelled with different letters are significantly different at p<0.05. 92 rahman et al. fig. 5. effect of variety, pre-hardening of seedlings and their interactions on unfilled grains panicle-1 of rice. data labelled with different letters are significantly different at p<0.05. interaction effect of pre-hardening treatments and rice genotypes interaction effect of rice genotypes and different seedling pre-hardening treatments differed significantly in yield attributing characteristics and different yield parameters (figure 7-10). the best combination was observed by the interaction of brri hybriddhan4 with seedling pre-hardening under open field storage conditions which contributed to improve all yield contributing characteristics except non-effective tiller. the combination of pajam and open field stored seedling produced more non-effective tillers. on the other hand, the lowest filled grain (75.13) was found by the interaction effect of brri dhan53 with without pre-hardening seedlings which was statistically similar with seedling storage in water with pajam variety and storage in open field and cool air treatment with brri dhan53. the lowest 1000-grain weight (15.03 g) was found with the interaction effect of pajam with direct transplanting after uprooting from the seedbed. 93 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice fig. 6. effect of variety, pre-hardening of seedlings and their interactions on 1000grain weight of rice. data labelled with different letters are significantly different at p<0.05. fig. 7. effect of variety, pre-hardening of seedlings and their interactions on grain yield of rice. data labelled with different letters are significantly different at p<0.05. 94 rahman et al. fig. 8. effect of variety, pre-hardening of seedlings and their interactions on straw yield of rice. data labelled with different letters are significantly different at p<0.05. fig. 9. effect of variety, pre-hardening of seedlings and their interactions on biological yield of rice. data labelled with different letters are significantly different at p<0.05. the maximum grain yield (7.26 t ha-1) and straw yield (6.77 t ha-1) were recorded from the interaction of brri hybriddhan4 and open field storage treatment condition which was statistically similar with brri hybriddhan4 and storage in cool air treatment. biological yield is the combination of grain and straw yield. the maximum harvest index (56.18%) was observed in direct transplanting seedlings of the hybrid variety, which was statistically similar with storage in water (55.57%), storage in shade (54.43%), and directs transplanting (53.95%) and storage in cool air treatment of hybrid variety. 95 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice fig. 10. effect of variety, pre-hardening of seedlings and their interactions on harvest index of rice. data labelled with different letters are significantly different at p<0.05 several pre-hardening of seedling were adapted in three rice genotypes (hybrid, inbred and local) to evaluate the varietal difference and the influence of pre-hardening of seedling on different yield contributing attributes and yields for convenient rice productions. as shown above, some of them had good predicting values and could be recommended as a good approach under unwanted situations of rice transplanting, while others showed little effect on rice productions. the possible reasons for these differences are discussed below. hybrid varieties out-yielded the inbred hybrid rice varieties exhibited higher yield and yield attributes over inbred varieties due to their inherent characteristics. hybrid varieties have 15-30% more yield potentiality over the inbred varieties which is the outcome of some agronomical and physiological mechanisms (julfiquar et al., 2002 and peng et al., 1999). hybrid rice varieties have more photosynthesis capacity because of containing higher amount of chlorophyll in their leaf (tang et al., 2010). in addition, flag leaf of hybrid rice contained more chlorophyll than the inbred rice genotypes which contributed to increase the photosynthesis capacity during panicle initiation (haque et al., 2015). higher photosynthesis potentiality of hybrid varieties attributed to accumulate higher amount of dry matter. the ultimate effect of accumulation of dry matter is to increase tiller number and vigorous growth over the inbred varieties. it has been suggested that accumulation of higher amount of dry matter before heading stage triggers the translocation of assimilated to the grain filling resulting higher number of filled grain, 1000-grain weight and ultimate yields over the modern and/or inbred varieties (laza et al., 2003). grain yield of rice depends on the source-sink relationship (zhao et al., 2006). hybrid varieties have efficient capacity to supply assimilates to the grain from the source and the capacity of the 96 rahman et al. sink to receive it fixes the higher yield than the inbred varieties (haque et al., 2015). the number of unfilled grain increased in brri hybriddhan4 than the two inbred varieties. it could be happened due to high temperature during growing season. researcher indicated that pollen sterility increased in hybrid varieties over 33ºc (chakrabarti et al., 2010). in the other hand, relatively high temperature impaired slow rate of translocation of assimilated from source to sink ultimately causes higher unfilled grain in hybrid rice than inbred (haque et al., 2015). pre-hardening of seedling influences for more rice production than direct transplanting seedlings pre-hardening under different conditions enhanced the yield and its attributes over direct transplanting of rice uprooted from seedbed before transplanting. it can be explained by the fact that under hardening conditions some physiological and biochemical changes might be happened in the seedlings for acclimatization under unwanted environmental conditions. at less stressful conditions like low temperature, short-term drought exposure often induces a variety of biochemical, physiological and enzymatic change in plant, which can result in an acclimation response. low temperatures induce a number of adjustments in cellular components, including the extent of unsaturated fatty acids, the composition of glycerolipids, changes in protein and carbohydrate composition and increase accumulation of sucrose and other simple sugars, proline that contributes to the stabilization of membrane (mahajan and tuteja, 2003). it has been investigated that that short period of chilling effectively enhances the proline accumulation in plants (habibi et al., 2011). proline is one of the main components of defense mechanism of the plant. the accumulation of proline has a great role in protecting protein structure, redox regulation, osmotic adjustment, reactive oxygen species scavenging, and storing nitrogen and carbon for future use under less stressful conditions (mattioni et al. 1997). proline accumulation occurs in plant organs under any abiotic stress at a certain level and acts as a signal/regulatory compound which facilitates various physiological or molecular processes resulting increase the tolerance level of any kind of stress (parveen et al., 2013). pre-hardening seedlings storage under open air condition for 48 h and 4°c low temperature conditions might be induces short-term drought and old stress which helps to accumulation of compatible solutes like proline, sucrose and quaternary ammonium derivatives. short-term stresses induction might be enhanced tolerance level of seedlings and helps to quick recovery in the main field and established growth, production of dry matter and tiller number during growth periods. more accumulation of dry matter by more photosynthesis contributes to improve yield attributing characteristics during reproductive stage of crop by the effect of source-sink relationship. the ultimate effect of increasing all yield contributing characteristics causes more yields. on the other hand, direct transplanting seedlings after immediate uprooted from seedbed take more time to establish in the field due to their root injury which affect their grow and yield. conclusion in summary, hybrid variety brri hybriddhan4 over-yielded the modern and local inbred varieties (brri dhan53 and pajam) due to higher yield attributing characters. pre-hardening seedlings under open air for 48 h triggered the ultimate yield advantage over direct transplanting after uprooting from the seedbed. references 97 pre-planting hardening-induced variability in yield attributes and yield of inbreed and hybrid rice alauddin, m. h. 2004. effect of methods of transplanting and seedlings per hill on the growth and yield of transplant aman rice cv. brri dhan39. m. s. thesis. dept. of agron., bau, maymensingh, bangladesh. bbs (bangladesh bureau of statistics). 2014. yearbook of agricultural statistics, 2014. chakrabarti, b., p. k. aggarwal, s. d. singh, s. nagarajan and h. pathak. 2010. impact of high temperature on pollen germination and spikelet sterility in rice: comparison between basmati and non-basmati varieties. crop past. sci. 61(5): 363-368. farooq, m., s. m. a. basra and n. ahmad. 2005. rice seed priming. intl. rice res. notes. 30(2): 45-47. habibi, f., h. normahamadi, a. sharifabad, eivazi and m. heravan. 2011. effect of cold stress on cell membrane stability, chlorophyll a and b contain and proline accumulation in wheat (triticum aiestivum l.) variety. afr. j. agric. res. 6: 5854-5859. haque, m. m., h. r. pramanik, j. k. biswas, k. m. iftekharuddaula and m. hasanuzzaman. 2015. comparative performance of hybrid and elite inbred rice varieties with respect to their source-sink relationship. sci. world j. doi: 10.1155/2015/326802 julfiquar, w., m. j. hasan, a. k. azad and a. m. nurunnab. 2002. research and development of hybrid rice in bangladesh. in: hybrid rice in bangladesh: progress and future strategies. bangladesh rice research institute, gazipur, bangladesh. pp. 9-19. laza, m. r. c., s. peng, s. akita and h. saka. 2003. contribution of biomass partitioning and translocation to grain yield under sub optimum growing conditions in irrigated rice. plant prod. sci. 6(1): 28-35. mahajan, s. and n. tuteja. 2005. cold, salinity and drought stresses: an overview. arch. biochem. biophys. 444: 139-158. mattioni, c., n. g. lacerenze, a. troccoli, a. m. deleonardis and n. difonzo. 1997. water and salt stress-induced alterations in proline metabolism of triticum durum seedlings. physiol. plant. 101: 787-792. peng, s., k. g. cassman, s. s. virmani, j. sheehy and g. s. khush. 1999. yield potential trends of tropical rice since the release of ir8 and the challenge of increasing rice yield potential. crop sci. 39(6): 1552–1559. perveen, s., i. s. kamran, j. mehmood, m. ijaz, r. shafiq, a. k. murad and j. muhammad. 2013. low temperature stress induced changes in biochemical parameters, protein banding pattern and expression of zat12 and myb genes in rice seedling. j. stress physiol. biochem. 9(4): 193-206. rajshekar, c. b. and a. lafta. 1996. cell-well changes and cell tension in response to cold acclimation and exogenous abscisic acid in leaves and cell culture. plant physiol. 111: 605-611. tang, w. b., g. l. zhang and y. h. xiao. 2010. physiological and biochemical characteristicsin flag leaves of the c liangyou series of rice hybrid combinations at late growth stages. rice sci. 17(4): 319-325. zhao, b. h., p. wang, h. x. zhang, q. s. zhu and j. c. yang. 2006. source-sink and grain filling characteristics of two-line hybrid rice yangliangyou 6. rice sci. 13: 34-42. bangladesh agron. j. 2014, 17(1): 67-72 foliar and soil fertilization effect on seed yield and protein content of soybean m. a. mannan department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh corresponding author: mannanbsmrau@yahoo.com key words: soybean, yield, protein content, foliar and soil fertilization abstract a field experiment was carried out at agronomy farm of patuakhali science and technology university, dumki, patuakhali, from december 2011 to march 2012, to study the effects of nutrient foliar spray on soybean growth, yield and protein content. soybean variety shohag was used as the test crop. n, npk, npks and npkmg were sprayed and applied in the soil at vegetative and pod filling stages. soil fertilizations were done as recommended dose, and no soil and foliar fertilization were considered as control. plants were sprayed at the rate of 100 mg/l of water corresponding to each nutrient. the experimental design was a split plot with three replications. result indicated that nutrient foliar spray, either singly or in combination, enhanced the growth and yield of the soybean as well as protein content in soybean seed, at the two growth stages compared to soil fertilization. however, spraying nutrients during pod filling stage was better than vegetative spraying stage in all characters studied. the highest amount of protein content in soybean seed and grain yield were obtained by spraying npkmg. introduction soybean (glycine max (l) merr.) belongs to leguminous family ranked as a top oilseed crop, which provides approximately 50% edible oil of the world (akparobi, 2009). it has been recognized as an ancient crop plant since the origin of agriculture (jandong et al., 2011). due to the large amount of macro and micro nutrients, it has been considered as a nutritious food for human needs, livestock, industrial and medicinal purposes (akparobi, 2009). soybean seed consists of 18 to 25% oil and 30 to 50% protein. protein of soybean seed contains amino acids required for human nutrition and livestock (raei et al., 2008). salwa et al. (2011) stated that soybean is a crop that compensates shortage of oil and protein of other crops. furthermore, it is a good source for high energy, protein and essential nutrients to human and animals. a successful initiative to introduce soybean in bangladesh was taken in the beginning of the eighties. at present soybean is not extracted in our country for oil because of lacking industrial facilities and is consumed as food products (soya-milk, soya-meat, soya-flour etc.) and ingredients of animals and poultry feed. usually, more than 95 % of the total population of bangladesh cannot afford protein rich food like fish, meat, egg, milk etc. due to higher price and low production. so, as supplement of low cost protein, soybean should be cultivated in more areas which can help to alleviate protein calorie malnutrition of cereal based diet in bangladesh. for optimum plant growth, nutrients must be balanced or in other words the soil must have nutrients that are needed for plants (chen, 2006). biological n2 fixation and mineral soil or nitrogen fertilizer are the main source of meeting the nitrogen (n) requirement of high-yielding soybean (salvagiottiet et al., 2008). the mineral nutrition of crops can be supplemented with fertilizer application to soils or foliage (mallarino et al., 2001). fertilization with n, phosphorus (p), potassium (k) and other nutrients can affect yield and many physiological processes, which in turn could influence grain yield and protein concentration (haq and mallarino, 2005). foliar spraying is a new method for crop feeding, which nutrients in form of liquid are used into leaves (nasiri et al., 2010). foliar application of nutrient elements is more beneficial than soil application. since application rates are lesser as compared to soil application, mailto:mannanbsmrau@yahoo.com 68 m. a. mannan and crop reacts to nutrient application immediately (zayed et al., 2011). soybean higher yield and quality as well as its oil could be be obtained by foliar spray of nutrient elements (vahedi, 2011). arif et al. (2006) found that based on soil properties, foliar spraying could be effective 6 to 20 times as compared to soil application. foliar application could be an advantage for crop growth (seifinadergholi et al., 2011). the objective of this study was therefore to assess the effect of foliar nutrient spray singly or in combinations before flowering and pod filling stages, on the growth, yield and seed quality of soybean. materials and methods the field experiment was carried out at agronomy farm of patuakhali science and technology university, dumki, patuakhali, from december 2011 to march 2012 to determine the effects of foliar spray of nutrients on the growth, yield and protein content of soybean seed. before planting, soil samples were collected from experimental area at 0-30 cm depth. the results of soil analysis were shown in table 1. the soybean variety used was shohag. the experimental design was splitplot having 4 m x 2.5 m plot size with three replications. table 1. physical and chemical properties of experimental soil soil properties value soil texture clay silt (%) 28.2 clay (%) 68.5 sand (%) 3.3 organic matter (%) 1.6 ph 6.2 electrical conductivity (ds m-1) 1.45 n (%) 0.66 p (ppm) 5.60 k (ppm) 5.31 zinc (mg kg-1) 1.09 iron (mg kg-1) 2.76 manganese (mg kg-1) 2.00 each block (replicate) was divided into main plots where growth stages (vegetative and pod filling) and six subplots to which nutrients were foliarly applied as exclusively n, npk, npks and npkmg at the rate of 100 mg litre-1 of each nutrient were randomly assigned. soil fertilizations were done as recommended dose and no soil and foliar fertilization in control plot. nitrogen was derived from urea, phosphorus from sodium dihydrogen orthophosphate (na2h2po4.2h2o), potassium from potassium chloride (kcl), sulphur from gypsum (caso4) and magnesium from hydrated magnesium chloride (mgcl2.6h2o). planting of seeds was done on 03 december, 2011 maintain spacing 30 cm x 5 cm. weeding was done at 2 and 6 weeks after sowing (was). plants were sprayed at vegetative (4 weeks after sowing) and pod filling (8 weeks after sowing) stages as per treatment. ten selected plants were used to take the data from each plot of each replication. data were recorded for grain yield, plant height, dry weight of different plant parts, number of pods plant-1, number of seeds pod-1 and 100 grain weight. the nitrogen concentration in seeds was measured with micro-kjeldahl method as described by peach and tracey (1956) and the seed protein content was determined by multiplying the nitrogen percentage and protein factor using the formula, protein percentage = nitrogen percentage x 5.71 (breese, 1931). data collected were analyzed using mstatc program. the means differences among the treatments were compared by least significance difference test (lsd). 69 foliar and soil fertilization effect on soybean results and discussion effects of foliar spray on plant height and dry matter production the data presented in table 2 showed that the foliar application of essential mineral nutrients, either singly or in combinations, was consistently beneficial to soybean growth and development. similarly, foliar spray during the vegetative and pod filling stages, also enhanced the performance of soybean. this result agreed with the work of tayo (1981). table 2. effects of foliar spray on plant height and dry matter production of soybean interaction of growth stages and nutrients plant height (cm) number of branches plant-1 stem dry weight (g) leaf dry weight (g) total dry weight (g) v x control 39.92 3.00 9.40 15.51 24.94 v x n 41.05 4.11 10.49 16.47 26.96 v x npk 44.24 5.11 9.86 19.16 29.02 v x npks 44.61 5.33 11.12 20.43 31.55 v x npkmg 46.92 7.38 11.95 21.63 33.58 v x r 43.72 4.35 9.89 16.95 26.84 p x control 41.85 3.67 10.09 18.89 28.98 p x n 42.45 5.00 11.02 20.10 31.12 p x npk 42.97 6.00 12.71 20.95 33.66 p x npks 43.51 7.67 13.59 21.79 35.38 p x npkmg 44.85 8.68 14.97 23.47 38.44 p x r 42.26 5.86 10.51 21.54 32.05 lsd(0.05) 8.29 1.53 2.54 15.50 16.39 cv (%) 10.24 9.49 10.17 12.35 13.37 vvegetative stage, p – pod filling stage, control (no soil and foliar fertilization), nfoliar spray with single n, npkfoliar spray with npk, npks foliar spray with npks, npkmg foliar spray with npkmg, r recommended fertilizer dose (1/2 n and full pk basal dose in soil + ½ n top dressing) plant sprayed with different nutrient combination generally had significantly higher plant height, higher number of branches, leaf dry weight, stem dry weight and total dry weight than control plants. plant spraying with npkmg produced the tallest plant with the highest total dry matter production in both the spraying stages. this could be that mg is important in chlorophyll formation, resulting in higher photosynthesis and higher leaf growth. stimulated photosynthetic activity and synthesis of chloroplast and protein which might have resulted in higher dry matter production as reported in soybean crop (mishra and agrawal, 1994). spraying during the pod filing growth stage led to plants with higher plant height, branches plant-1, stem dry weight, leaf dry weight and total dry weight than that of spraying during vegetative stage. this was probably due to the fact that all plants had reached the peak of vegetative growth before spraying was done. the fact that spraying during the pod filling growth stage would be ultimately better than spraying at vegetative stage, since the former plants had significantly higher values of all the parameter studied. yield attributes and protein of seed number of pods: number of pods plant-1 is an important yield component in soybean and all the foliar spray treatments viz., n, npk, npks and npkmg increased the number of pods plant-1 at both growth stages (table 3). the foliage applied nitrogen and phosphorus at the vegetative stage might have effectively absorbed and translocated to the pods resulting in more number of pods plant-1. the results obtained by solaiappan et al. (2002) in redgram are concomitant to the present finding. foliar spray of these nutrients at pod filling stage of crop growth might have caused efficient translocation of 70 m. a. mannan photosynthates from source to sink. however, sprayed with npkmg during the pod filling stages of growth was higher and significantly different from those plants sprayed during at vegetative stage of growth. the foliar application of nutrients through npkmg at pod filling stage might have reduced flower drops. this might have significantly increased the number of pods plant-1 as reported by ganapaty et al. (2008). number of seed pod-1 and seed index: foliar application of essential nutrients during vegetative and pod filling stages of crop growth significantly influenced the number of seed pod-1 and 100-seed weight (table 3). this might be due to better absorption of nutrients applied through foliage leading to better activity of functional root nodules resulting in more dry matter production. this could have lead to more flower production and subsequently pod formation and other yield attributes. the increased 100-seed weight might be attributed to increased mobilization of metabolites to the reproductive sinks. furthermore, plants sprayed with npkmg during pod filling stage had significantly the highest number of pods plant-1 and 100-seed weight in respect of sprayed at vegetative stage. table 3. effects of foliar spray on yield, yield contributing characters and protein % of soybean interaction of growth stages and nutrients pods number per plant seed number per pod 100-seed weight (g) grain yield m-2 (g) protein (%) v x control 83.67 2.06 4.83 155.10 21.33 v x n 85.70 2.23 6.01 164.34 25.00 v x npk 85.38 2.50 7.92 170.09 30.00 v x npks 87.00 2.60 8.39 171.37 31.10 v x npkmg 90.33 3.00 10.0 182.74 35.67 v x r 84.65 2.33 5.66 169.05 27.45 p x control 85.09 2.30 6.85 148.40 21.00 p x n 86.00 2.56 7.63 165.07 26.00 p x npk 87.67 2.73 8.19 173.75 29.33 p x npks 88.49 2.83 9.24 174.60 33.00 p x npkmg 92.67 3.13 12.52 187.20 37.33 p x r 86.55 2.46 7.03 169.30 27.33 lsd(0.05) 2.01 0.35 2.06 10.47 3.69 cv (%) 1.64 5.93 9.31 3.80 5.09 vvegetative stage, p – pod filling stage, control (no soil and foliar fertilization), nfoliar spray with single n, npkfoliar spray with npk, npks foliar spray with npks, npkmg foliar spray with npkmg, r recommended fertilizer dose (1/2 n and full pk basal dose in soil + ½ n top dressing) grain yield and protein (%) in seed: interaction effects of foliar application of different nutrients and growth stages had significant variations in grain yield and protein content (table 3). plant sprayed with npkmg during vegetative and pod filling stages shown a better performance in grain yield and yield contributing attributes and protein % compared with other treatment combinations. foliar spraying during the pod filling stage was more effective than during vegetative stage in all the parameters studied, probably because nutrients applied during pod filling were readily used for photosynthesis and assimilates quickly mobilized for grain filing and protein accumulation in grain. the increased yield might be due to enhanced yield attributes like number of pods plant-1, number of seeds pod-1, 100-seed weight due to increased uptake of nutrients by soybean by effective translocation of nutrients from sink to reproductive area of crop. spraying with npkmg during pod filling stage enhanced yield and protein content of soybean, compared with other nutrient combinations. this agreed with the work of ashour and thallooth (1983). in conclusion, it appears that nutrient spraying enhanced soybean growth, development, yield and protein content and 71 foliar and soil fertilization effect on soybean spraying in the pod filling stage is better than spraying during vegetative stage. as for the nutrient combinations, npkmg appear to give the highest yield and protein content of soybean. acknowledgement the author is grateful to the faculty of higher studies, patuakhali science and technology university, patuakhali for funding this study. references akparobi, s. o. 2009. evaluation of six cultivars of soybean under the soil of rainforest agro-ecological zones of nigeria. middle-east j. sci. res. 4(1): 06-09. available online at: http://idosi.org/mejsr/mejsr4(1)/2.pdf. arif, m., m. a. chohan, s. ali, r. gul and s. khan. 2006. response of wheat to foliar application of nutrients. j. agric. biol. sci. 1(4). available online at: http://www.arpnjournals.com/jabs/ research_papers/jabs_1106_36.pdf. ashour, n. i. and a. t. thalloth. 1983. effects of soil and foliar application of n during pod development and yield of soybean (glycine max, (l) merill) plants. field crops res. 6: 261-266. breese, j. 1931. factors for converting percentage of nitrogen in foods and feeds into percentages of protein. united statesd.partment of agriculture washington, p.22. chen, j. 2006. the combined use of chemical and organic fertilizer and/or biofertilizer for crop growth and soil fertility. taipei food fert. technol. bull., 17: 1-9. ganapaty, m., g. baradban and n. ramesh. 2008. effect of foliar nutrition on reproductive efficiency and grain yield of rice fallow pulses. legume res. 31: 142-144. haq, m. u. and a. p. mallarino. 2005. respones of soybean grain oil and protein concentrations to foliar and soil fertilization. agron. j. 97: 910918. http://www.academicjournals.org/jmpr/pdf/pdf2010/4sept/nasiri%20 et% 20al.pdf. jandong, e. a, m. i. uguru and b. c. oyiga. 2011. determination of yield stability of seven soybean (glycine max) genotypes across diverse soil ph levels using gge biplot analysis. j. appl. biosci. 43: 29242941. mallarino, a. p., m. u. haq, d. wittry and m. bermudez. 2001. variation in soybean response to early season foliar fertilization among and within fields. agron. j. 93: 1220-1226. available online at: https://www.soils.org/publications/aj/pdfs/93/6/1220. mishra, a. k. and h. p. agarwal. 1994. effect of sulphur on growth, yield, protein and oil content of soybean. j. oilseeds res. 11: 99-102. nasiri y., s. zehtab-salmasi, s. nasrullahzadeh, n. najafi and k. ghassemigolezani. 2010. effects of foliar application of micronutrients (fe and zn) on flower yield and essential oil of chamomile (matricaria chamomilla l.). j. med. plants res. 4(17): 1733-1737. peach k. and m. v. tracey. 1956. modern methods of plant analysis. springer-verlag, berlin. raei. e., m. sedghi and r. sayed sharifi. 2008. effect of bradirizobium inoculation, application of nitrogen and weeding on growth and seed filling rate in soybean. j. agric. technol. 12(43): 91-81. salvagiottiet, f., k. g. cassman, j. e. specht, d. t. walters, a. wiss and a. dobermann. 2008. nitrogen uptake, fixation and response to fertilizer n in soybean: a review. field crop res. 108: 1-13. http://idosi.org/mejsr/mejsr4(1)/2.pdf http://www.arpnjournals.com/jabs/research_papers/jabs_1106_36.pdf http://www.arpnjournals.com/jabs/research_papers/jabs_1106_36.pdf http://www.academicjournals.org/jmpr/pdf/pdf2010/4sept/nasiri https://www.soils.org/publications/aj/pdfs/93/6/1220 72 m. a. mannan salwa, a. i. e., m. b. taha and m. a. m. abdalla. 2011. amendment of soil fertility and augmentation of the quantity and quality of soybean crop by using phosphorus and micronutrients. intl. j. acad. res. 3(2): part 3. available online at: http://www.ijar.lit.az/pdf/10/2011(10-127).pdf. seifinadergholi, m., m. yarnia and f. rahimzade khoei. 2011. effect of zinc and manganese and their application method on yield and yield components of common bean (phaseolus vulgaris l. cv. khomein). middle-east j. sci. res. 8(5): 859-865. solaiappan, d., v. k. paulpandi and n. chellaiah. 2002. effect of graded levels of phosphorus and foliar fertilization on short duration redgram in rainfed vertisol. madras agric. j. 87: 451-454. tayo, t. o. 1981. studies on the effects of foiar spray of nutrients on the performance of cowpea (vigna unguiculata (l) walp). j. agril. sci. camb. cult. sci., cambridge, 96: 375-388. vahedi, a. 2011. the effects of micronutrient application on soybean seed yield and on seed oil and protein content. j. am. sci. 7(6). available online at: http://www.jofamericanscience.org/ journals/amsci/0706/110_5746am0706_672_677.pdf. zayed, b. a., a. k. m. salem and h. m. el sharkawy. 2011. effect of different micronutrient treatments on rice (oryza sativa l.) growth and yield under saline soil conditions. world j. agric. sci. 7(2): 179184. available online at: http://www.idosi.org/wjas/wjas7 (2)/12.pdf. http://www.ijar.lit.az/pdf/10/2011(10-127).pdf http://www.jofamericanscience.org/journals/amsci/ http://www.jofamericanscience.org/journals/amsci/ alleviation of adverse effect of drought stress on soybean (glycine max bangladesh agron. j. 2016, 19(2): 61-69 alleviation of adverse effect of drought stress on soybean (glycine max. l.) by using poultry litter biochar m. a. mannan1*, e. halder1, m. a. karim1 and j. u. ahmed2 1department of agronomy, 2department of crop botany bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding author: mannanbsmrau@yahoo.com key words: biochar, alleviation, drought, tolerance, soybean abstract the experiment was conducted under controlled condition at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, bangladesh from january to april 2015 to clarify the mechanism that might be involved in the ameliorating effects of poultry litter biochar on soybean plants grown under water deficit stress. the treatments were (i) water regimes (well watered and 40% field capacity) and (ii) biochar (0, 25, 50 and 100 t ha-1). results indicated that water deficit stress induced reduction in growth, leaf water and chlorophyll content and yield of soybean plant compared with those of the unstressed plants. on the other hand, water deficit stress led to increases in proline content. the improvement of drought tolerance resulted from biochar application were accompanied with improved water and proline accumulation as well as less degradation of chlorophyll in leaf was observed. these results clearly demonstrate that harmful effect of drought could reduce on plant height, leaf water and chlorophyll contents and yield of soybean. consequently, application of poultry litter biochar is a good strategy to effectively solve the seasonal drought stress problem in dry lands. introduction drought is the most severe abiotic stress factor limiting plant growth and crop production (moussa, 2011; rohbakhsh, 2013). drought stress is characterized by reduction of water content, diminished leaf water potential and turgor loss, closure of stomata and decrease in cell enlargement and growth. severe water stress may result in the arrest of photosynthesis, disturbance of metabolism and finally the death of plant (jaleel et al., 2008). drought stress inhibits cell enlargement more than cell division. it reduces plant growth by affecting various physiological and biochemical processes, such as photosynthesis, respiration, translocation, ion uptake, carbohydrates, nutrient metabolism and growth promoters (farooq et al., 2008). it affects both elongation and expansion growth (anjum et al., 2003; bhatt & rao, 2005; kusaka et al., 2005; shao et al., 2008) which ultimately affects the yield of plants. biochar is pyrolysed organic material intended for use as a soil amendment to sustainably sequester c and concurrently improve soil function, while avoiding any adverse effects, on both the short and long terms (lehmann and joseph, 2009). in recent years, application of ‘biochar’ has been increasingly discussed as a mitigation strategy for sequestering recalcitrant carbon into agricultural soils, which can, at the same time, improve soil fertility (glaser et al., 2002; lehmann, 2006). experimental evidence so far shows that incorporation of biochar to soil enhanced soil water-holding capacity (asai et al., 2009; laird et al., 2010; karhu et al., 2011), improved soil water permeability (asai et al., 2009), improved saturated hydraulic conductivity (shc) (asai et al., 2009), reduced soil strength (chan et al., 2007, 2008; busscher et al., 2010), modification in soil bulk density (ρb) (laird et al., 2010) and modified mailto:mannanbsmrau@yahoo.com 62 mannan et al. aggregate stability (busscher et al., 2010; peng et al., 2011). due to its physical properties, bc help increase water holding capacity and reduces nutrient leaching. biochar is very porous which increases adsorption properties allowing a greater retention of water and nutrients in the soil solution (adams et al., 2013). one greenhouse study found that the water holding capacity nearly doubled when 15% poultry litter bc by weight was added to 9 kg of sandy loam soil. the ability to retain a relatively large quantity of water aids plant growth when under water stress. in another greenhouse study, artiola et al. (2012) was found that soil amended with 2% and 4% bc by weight (15 kg of loamy sand used) had higher yields than control plants after undergoing water stress. biochar can be an important tool to increase food security and cropland diversity in areas with severely depleted soils, scarce organic resources, and drought prone areas. the addition of biochar to sandy soil changes soil characteristics such as its texture and porosity. hypothetically, finer textured soils (after biochar addition) in arid climates should be associated with more negative plant and soil water potentials during drought, inducing a greater resistance of xylem to cavitation, and shallower root systems than coarse soils. the aim of this study was to investigate the poultry litter biochar effects on growth, physiology and yield of soybean plant under well water and low water availability. materials and methods the experiment was carried out at bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh from january to april 2015. the semi controlled polythene house pot experiment was designed as a completely randomized experiment with 4 replicates, with sufficient (well watered) or reduced water (40% field capacity) supply and 0 (control), 25, 50 and 100 t ha-1 poultry litter biochar application rates. the soil was a sandy loam with ph (6.93), total n (0.07%), available p (0.08 mg 100 g-1), exchangeable k (0.79 cmolc kg -1 dry soil), available s (10 ppm), organic carbon (0.61%), cec (13.05 cmolc kg -1 dry soil) and ec 0.4 ds m-1. the pots were made from commercial polyethylene pipes with three draining holes at bottom. each of the 24 pots (inner diameter 24 cm, height 30 cm) was filled with air-dried soil or soil and biochar mixture. for biochar treatments, 122, 244 and 488 g dry biochar were added per pot and thoroughly mixed with the soil, equivalent to 25, 50 and 100 t biochar ha-1, respectively. thus, the soil surface in the biochar-amended pots was 4-7 cm higher than in the control pots. the biochar had been produced from poultry litter by pyrolysis in biochar stove. the average residence time was 5 hours and the temperature range was 300-3500c. fifteen (15) kg dry poultry litter was pyrolysed each time and produced 3.5 kg biochar on an average. the ph, total nitrogen and available phosphorus of biochar were 6.93, 1.65% and 31.81 ppm, respectively. exchangeable k (meq 100 g-1 biochar), ca (meq 100 g-1 biochar), mg (meq 100 g-1 biochar) and sulphur (ppm) were 3.6, 10.08, 2.75 and 870.70, respectively. the water holding capacity (whc) of the soilbiochar mixtures was determined by submerging the entire pots for 24 h, and subsequent draining for another 24 h and it was about 28% moisture at field capacity (fc). k-value was determined to calculate the weight of the air-dried soil or soil biochar mixture at 100% field capacity. weight of each individual empty pot was measured. amount of the air dried soil and soil and biochar mixture of each individual pot was measured by deducting the weight of the empty pot. then oven dry weight of this soil was measured by multiplying the k-value. weight of the air dried soil and soil biochar mixture at 100% field capacity was measured. then amount of water at 80% field capacity and 40 % field capacity of that soil and soil biochar mixture was measured. then pot weight was measured at 80% field capacity and 40% field capacity. ten seeds of soybean var. bari soybean-6 were sown into each pot. after 14 days, 63 alleviation of adverse effect of drought stress on soybean (glycine max. l.) by using poultry litter biochar when seedlings had trifoliate stage six uniform and healthy plants were kept. the amount of water at 80% and 40% fc were chosen as “well watered” and “drought stress” treatment, respectively. however, since plants showed severe wilting symptoms, the “drought stress” treatment was adjusted to 40% fc. afterwards, the pots were weighed every 1 to 2 days, the respective water loss was recorded, and water was applied to achieve the desired target 80 % and 40 % of the fc. data on plant height, relative water, proline, chlorophyll a, chlorophyll b and total chlorophyll contents in leaf, pod plant-1, seed pod-1, 100seed weight and yield plant-1 were recorded. the data recorded on different parameters were statistically analyzed with the help of mstat-c program and the difference between the treatments means were compared by lsd test (gomez and gomez, 1984). results and discussions plant height: results in fig.1 showed that drought stress decreased plant height significantly as compared with well watered plants. plant height reduction was 20.35% due to water stress when no biochar was applied in soil. this finding is in agreement with the results of nielsen and nelson (1998) and shenkut and brick (2003) who reported on depression of plant height as a result of severe influence from environmental factors such as water stress. application of biochar in soil caused significant increases in plant height as compared with drought stressed plants and well watered plants. plant height increased significantly by application of poultry litter biochar in soil both in well water and water stress conditions compare to no biochar condition. under water stress condition plant height increased 3.30%, 6.07% and 4.03% by application of biochar 25, 50 and 100 t ha-1, respectively compared to without biochar treatment. hogan (2011) observed that biochar usually has the potential of activating soil micro organisms and increasing the water retention capacity of the soil thereby increasing photosynthetic rate and consequent increase in height of plants. fig. 1. effect of poultry litter biochar on plant height under well watered and drought conditions. bars indicates lsd at 5% level. relative water content limited soil water always significantly impacted the plant physiological parameters 64 mannan et al. including the relative water content. drought stress reduced relative water content by 7.32% in soybean leaf (fig. 2). this result is in agreement with siddique et al. (2001) and they found that water-stressed wheat and rice plants had lower relative water content than non-stressed ones. however, biochar addition supported the plants at both water regimes. relative water content increased by addition of biochar both in well water and water stress conditions. in well water condition relative water content increased 3.83, 5.25 and 3.51 % and in water stress condition it was 4.35, 6.81 and 4.92 % by addition of biochar 25, 50 and 100 t ha−1, respectively. in line with the findings of gaskin et al. (2010), biochar addition also increased the overall accumulation of osmotic active substances such as k+ in the plant tissues, likely due to its large cation content, leading to an improved plant water uptake which ultimately increased water content in leaf. fig. 2. effects of poultry litter biochar on relative water content under well watered and drought conditions. bars indicates lsd at 5% level. chlorophyll content drought stress caused significant decrease in chlorophyll a, b and total photosynthetic pigments in leaves of soybean plant as compared with control plants (table 1). similar results are reported by ladjal et al. (2000); younis et al. (2000) and terzi et al. (2010) in some soybean species and this pigment were sensitive to increasing environmental stress. the decrease in these pigments may have resulted from a decrease in leaf water status in the soybean. abass and mohamed (2011) who reported that photosynthetic pigments contents in leaves of common bean plants were highly significantly decreased with increasing the level of drought stress. the reduction in chlorophyll content under drought stress has been considered a typical symptom of oxidative stress and may be the result of pigment photo-oxidation and chlorophyll degradation. the decrease in the photosynthetic activity under drought stress may be due to stomatal or non-stomatal mechanisms. stomata closure is one of the first responses to drought stress which result in declined rate of photosynthesis. the drought induced reduction in the chlorophyll content could be attributed to loss of chloroplast membranes, excessive swelling, and distortion of the lamellae vesiculation and the appearance of lipid droplets. addition of biochar in soil increased chlorophyll content under well water and stress conditions although it was not significant in case of chlorophyll a and total chlorophylls. in well water condition total chlorophyll content increased by 3.31, 3.12, 1.56 % and water stress condition it was 7.25, 29, 17 % when biochar application rate was 25, 50 and 100 t ha-1, respectively. highest increased of chlorophyll content was found under water stress condition when soil was 65 alleviation of adverse effect of drought stress on soybean (glycine max. l.) by using poultry litter biochar treated with biochar @ 50 t ha-1. lehmann et al (2006) reported that application of biochar in triticum aestivum l not only improve the availability of nutrients but also promote vegetative growth by improving the photosynthetic pigments chlorophyll (a, b and total) under stressed condition. table 1. effects of poultry litter biochar on chlorophyll a, chlorophyll b and total chlorophyll under well water and drought conditions treatments chlorophyll a (mg/g fresh wt. leaf) chlorophyll b (mg/g fresh wt. leaf) total chlorophyll (mg/g fresh wt. leaf) well water 40 % fc well water 40 % fc well water 40 % fc no biochar 1.97 1.46 0.59 0.46 2.56 1.92 biochar (25 t ha-1) 2.01 1.56 0.65 0.51 2.66 2.07 biochar (50 t ha-1) 2.02 1.78 0.86 0.67 2.88 2.45 biochar (100 t ha 1) 1.98 1.70 0.70 0.56 2.68 2.26 lsd (0.05) cv (%) ns 8.6 0.26 10.1 ns 11.3 proline content the proline content in leaf of soybean plants significantly increased under drought stress (fig.3). these results are in accordance with abass and mohamed (2011) who reported that the drought condition caused significant increase in the proline and soluble sugars content in shoot of common bean plants. in addition, the proline content significantly increased in leaf of soybean plants when the soil was treated with the different doses of biochar as compared with drought stressed plants and control plants. fig. 3. effects of poultry litter biochar on proline content under well watered and drought conditions. bars indicate lsd at 5% level. 66 mannan et al. in well watered condition proline content increased by 14.81 and 25.92 % when biochar was applied as 25 and 50 t ha-1, respectively compare to no biochar application. on the other hands it was 22.58 and 38.70 % compare to no biochar application when biochar was applied at the same doses under drought condition. but in case of biochar dose 100 t ha-1 does not follow the same increasing trend both water regimes. in this respect, the protection of soybean plants against drought stress by application of biochar is believed to be caused indirectly as a result of its effect on proline accumulation which play a protective role as scavenges of ros, resulted in improved adaptation ability and growth of plants under drought conditions (türkan and demiral, 2009). also, proline can act as a signaling molecule to modulate mitochondrial functions, influence cell proliferation or cell death and trigger specific gene expression, which can be essential for plant recovery from stress (szabados and savoure, 2010). seed yield and yield attributes water deficit stress decreased number of pod significantly compared to well watered condition (table 2). application of biochar increased pod number under well watered and water deficit conditions. in well watered condition, maximum number of pod/plant was obtained (42.67), when biochar was applied @ 50 t ha-1, followed by biochar rate 25 and 100 t ha-1 and it was lowest in no biochar application. on the other hand, in water deficit condition maximum number of pod/plant was obtained (26.67), when biochar was applied @ 50 t ha-1, followed by biochar 100 and 25 t ha-1 and it was lowest in no biochar application. a positive effect of biochar under water stress condition was found in case of number of seed/plant, seed weight as well as seed yield of soybean. highest seed yield was obtained when biochar was applied @ 50 t ha-1 under water stress condition. drought stress in soybean reduced total seed yield reported by frederick et al. (2001). biochar can increase the cation exchange capacity of soils (liang et al., 2006), soil ph (vaccari et al., 2011), and water holding capacity (laird et al., 2010), which would improve nutrient and water availability in the soils and thereby improve growing conditions for plants. some other studies have found increased aboveand below-ground biomass with biochar addition (kammann et al., 2011; vaccari et al., 2011) as well as increased plant height and leaf area (graber et al., 2010) which ultimately helps to increase grain yield of crops. table 2. effect of poultry litter biochar on seed yield and yield components under water deficit stress treatments number of pod plant-1 number of seed pod-1 100seed weight (g) seed yield plant1 (g) well water 40 % fc well water 40 % fc well water 40 % fc well water 40 % fc no biochar 38.67 19.67 1.53 1.85 10.77 10.12 5.36 3.74 biochar (25 t ha-1) 41.33 18.67 2.11 1.39 9.87 12.12 8.62 3.88 biochar (50 t ha-1) 42.67 26.67 1.71 1.65 12.2 12.92 8.81 4.77 biochar (100 t ha1) 41.00 20.33 2.15 1.25 11.92 10.35 10.46 2.63 lsd (0.05) 8.21 0.52 ns 2.71 cv (%) 9.6 10.9 8.8 7.5 conclusions from the results of this experiment it may be concluded that biochar application in 67 alleviation of adverse effect of drought stress on soybean (glycine max. l.) by using poultry litter biochar soil can be beneficial to mitigate drought stress effect. it was found that a biochar dose 50 t ha-1 showed higher performance compared to the other doses. references abass, s. m. and h. i. mohamed. 2011. alleviation of adverse effects of drought stress on common bean (phaseolus vulgarisl.) by exogenous application of hydrogen peroxide. bangladesh j. bot. 41: 75-83. adams, m. m. benjamin, t. j. emery, n. c. s. j. brouder , and k. d. gibson.2013. the effect of biochar on native and invasive prairie plant species. invasive plant sciand manag-. 6: 197-207. anjum, f., m. yaseen, e.rasool, a. wahid and s. anjum. 2003. water stress in barley (hordeum vulgare l.). i. effect on morphological characters. pak j. agric. sci. 40: 43-44. artiola, j. f., c. rasmussen and r. freitas. 2012. effects of a biocharamended alkaline soil on the growth of romaine lettuce and bermudagrass. soil sci. 177: 561-570. asai, h., b. k. samson, h. m. stephan, k. songyikhangsuthor, k. homma, y. kiyono, y. inoue, t. shiraiwa and t. horie. 2009. biochar amendment techniques for upland rice production in northern laos:1. soil physical properties, leaf spad and grain yield. field crops res.111: 81-84. bhatt, r. m. and n. k. rao. 2005. influence of pod load response of okra to water stress. indian j. plant physiol. 10: 54-59. busscher, w. j., j. m. novak, d. e. evans, d. w. watts, m. a. s. niandou and m. ahmedna. 2010. influence of pecan biochar on physical properties of anorfolk loamy sand. soil sci.175: 10-14. chan, k. y., l. vanzwieten, i. meszaros, a. downie and s. joseph 2007. agronomic values of green waste biochar as a soil amendment. aust. j. soil res. 45: 629634. farooq, m., t. aziz, s. m. a. basra, m. a. cheema and h. rehamn. 2008. chilling tolerance in hybrid maize induced by seed priming with salicylic acid, j. agron. crop sci. 194: 161–168. frederick, j. r., c. r. camp and p. j. bauer. 2001. drought-stress effects on branch and main stem seed yield and yield components of determinate soybean, crop sci. 41:759-763. gaskin, j. w., r. a. speir, k. harris, k. c. das, r. d. morris, l. a. lee and d. s. fisher. 2010. effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status, and yield. agron. j. 102: 623-633. glaser, b., j. lehmann and w. zech. 2002. ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review. biol. fertil. soils. 35: 219-230. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research, international rice research institute, john wiley and sons, newyork, chickester, brisbane,toronto, singapore. pp. 139-240. 68 mannan et al. graber, e. r., y. m. harel and m. kolton. 2010. biochar impact on development and productivity of pepper and tomato grown in fertigated soil less media. plant soil. 337: 481496. hogan, m. c. 2011. “respiration”. encyclopedia of earth.eds. mark mcginley and c. j. clevel and. national council for science and the environment. washington, d. c. jaleel, c. a., p. manivannan, g. m. a. lakshmanan, m. gomathinayagam and r. panneerselvam. 2008. alterations in morphological parameters and photosynthetic pigment responses of catharanthus roseus under soil water deficits. colloids surf. b. biointerfaces. 61: 298-303. kammann, c., s. linsel, j. gößling and h. w. koyro. 2011. influence of biocharon drought tolerance of chenopodium quinoa willd and on soil-plantrelations. plant soil. 345: 195-210. karhu, k., t. mattila, i. bergström and k. regina. 2011. biochar addition to agricultural soil increased ch4 uptake and water holding capacity-results from a short-term pilot field study. agric. ecosyst. environ. 140: 309-313. kusaka, m., m. ohta and t. fujimura. 2005. contribution of inorganic components to osmotic adjustment and leaf folding for drought tolerance in pearl millet. physiol. plant. 125: 474-489. ladjal, m., d. epron and m. ducrey. 2000. effects of drought preconditioning on thermotolerance of photosystem ii and susceptibility of photosynthesis to heat stress in cedar seedlings. tree. physiol. 20: 1235-1241. laird, d. a., p. fleming, d. d. davis, r. horton, b. q. wang and d. l. karlen. 2010. impact of biochar amendments on the quality of a typical midwestern agricultural soil. geoderma. 158: 443-449. lehmann, j. 2006. biochar sequestration in terrestrial ecosystems: a review. mitig. adapt. strateg. glob. chang.11: 403–427. lehmann, j., j. gaunt and m. rondon. 2006. biochar sequestration in terrestrial ecosystems–a review. mitigation and adaptation strategies for global change. 11(2): 403-427. lehmann, j. and s. joseph. 2009. biochar for environmental management: an introduction. in: j. lehmann and s. joseph (eds) biochar for environmental management, science and technology. earthscan. london. pp. 1-12. liang, b., j. lehmann, d. solomon, j. kinyangi, j. grossman, b. o"neill, j o. skjemstad, j. thies, f. j. luizao, j. petersen and e. g. neves. 2006. black carbon increases cation exchange capacity insoils. soil. sci. soc. am. j. 70: 719– 1730. moussa, h. r. 2011. low dose of gamma irradiation enhanced drought tolerance in soybean. acta. agro. hung. 59: 1-12. nielsen, d. c. and n. o. nelson. 1998. black bean sensitivity to water stress at various growth stage. crop. sci. 38: 422-427. peng, x., l. l. ye, c. h. wang. h. zhou and b. sun. 2011. temperature and duration dependent rice straw-derived biochar: characteristics and its effects on soil properties of anultisolin southern china. soil tillage res. 112: 159-166. rohbakhsh, h. 2013. alleviating adverse effects of water stress on growth and yield of forage sorghum by potassium application. adv. environ. biol. 7(1): 40-46. shao, h. b., l. y. chu, c. a. jaleel and c. x. zhao. 2008. water deficit stress induced anatomical changes in higher plants. cr. biol. 331: 215-225. shenkut, a. a. and m. a. brick. 2003. traits components in common bean associated http://www.eoearth.org/article/respiration?topic=74360 http://www.eoearth.org/article/respiration?topic=74360 69 alleviation of adverse effect of drought stress on soybean (glycine max. l.) by using poultry litter biochar 2 with dry edible bean (phaseolus vulgaris l.) productivity under diverse soil moisture environments. euphytica. 133: 339-347. siddique, m. r. b., a. hamid and m. s. islam. 2001. drought stress effects on water relations of wheat. bot. bull. acad.sinica.41: 35-39. szabados, l. and a. savouré. 2010. proline: a multifunctional amino acid. trends. plant. sci. 15: 89-97. terzi, r., a. sa ğlam, n. kutlu, h. nar and a of soil drought stress on photochemical efficiency of photosystem ii and anti-oxidant enzyme activities of phaseolus vulgaris cultivars. turk. j. bot. 34: 1-10. türkan, i. and t. demiral. 2009. recent developments in understanding salinity tolerance. environ. exp. bot. 67: 2-9. vaccari, f. p., s. baronti and e. lugato. 2011. biochar a sastrategy to sequester carbon and increase yield in durum wheat. eur. j. agron. 34: 231-238. witham, f. h., d. f. blaydes and r. m. devlin. 1986. chlorophyll absorption spectrum and quantitative determinations. in. exercise in plant physiology. second edition. boston. pp. 128-131. younis, m. e., o. a. el-shahaby, s. a. abo-hamedand a. h. ibrahim. 2000. effects of water stress on growth, pigments and 14co assimilation in three sorghum cultivars. j. agron. crop. sci. 185: 73-82. bangladesh agron. j. 2015, 18(2): 89-95 improving yield of transplanted aman and boro rice through tegra package of cultivation m.a.kader1*, m.s.r. mia1, m.a. kafi1, m. s. hossain2 and n. islam1 1department of agronomy, bau, mymensingh 2department of agronomy and haor agriculture, sylhet agricultural university, sylhet corresponding author: abdul.kader@bau.edu.bd key words: tegra; mechanical transplanting; rice yield gap; preventive plant protection abstract the study investigated the yield performance of transplant aman rice cv. brri dhan49 and boro rice cv. brri dhan29 under improved package of cultivation (tegra) as compared to farmers’ practice. tegra is a rice farming practice which includes use of quality seeds and healthy seedlings, transplanting with rice transplanter, use of herbicide, use of balanced fertilization and micronutrients, and preventive plant protection measures. the study during transplant aman season included two treatments on rice cultivation method viz. tegra package and farmers’ practice while in boro rice four treatments viz. tegra package, farmers’ practice with high inputs, farmers’ practice with medium inputs and farmers’ practice with low inputs. the yield and plant characters of both transplant aman and boro rice were significantly influenced by the tegra package of cultivation as compared to farmers’ practice. tegra package of cultivation as compared to farmers’ practice increased the grain yield by 18.3% in transplant aman rice and by 80% in boro rice with less cost of production as compared to farmers’ practice, which eventually resulted 23% increase in gross return and 400% in net return. as a result, the benefit cost ratio of tegra package was much higher (1.35 and 2.20 during transplant aman rice and boro rice, respectively) compared to that of farmers’ practice (1.07 and 1.30). introduction rice is the most important staple food in bangladesh covering more than 80% of the food grains consumed in the country. currently, 11.47 m hectares of land is occupied with rice cultivation having an annual production of about 34.36 million tons with an average yield of about 3.0 t ha-1 (brri, 2015a). on an average, the yield of the most popular transplant aman rice varieties ranges from 5.0 to 6.5 tha-1, (brri 2015b). however, the grain yield of 7.78 tha-1 of the variety brri dhan49 was also reported at filed level (kamruzzaman, 2014). the lower average yield of rice in the country is mainly due to inefficient management practices used by the farmers such as use of poor quality seeds, less care of seedlings in the nursery bed, manual transplanting, use of imbalanced fertilization, i improper weed and pest management practices etc recently, a package of rice cultivation, known as tegra, has been developed. the package is comprised of use of high quality rice seeds, raising of seedlings with special care in tray, use of tender seedlings for transplanting using mechanical transplanter, application of herbicides, balanced fertilization and preventive crop protection measures. the availability of labor became very scarce with high wages of labor, manual transplantingleading to reduced profits to farmers. it has been reported that transplanting takes about 250-300 man-hours/ha which is roughly 25 percent of the total labor requirement of the crop (singh et al. 1985).. mechanical transplanting has become popular in many countries due to its multidimensional advantages. the tegra package is 90 kader et al. expected to give at least 20% more yield to the farmers as compared to their own practice. therefore, the present study was conducted to evaluate the growth and yield performance of transplant aman rice cv. brri dhan49 and boro rice cv. brri dhan29 under tegra package of cultivation and compare with farmers practices. materials and methods the study was conducted at the agronomy field laboratory, bangladesh agricultural university (bau), mymensingh during the transplant aman season (july to november) in 2014 and boro season (december to june) in 2014-15 to ascertain the yield performance of transplant aman rice cv. brri dhan49 and boro rice cv. brri dhan29 under tegra package of cultivation as compared to farmers’ practices. the study during transplant aman season included two treatments on rice cultivation method viz. tegra package and farmers’ practice, while during boro season the experiment composed of four treatments on rice cultivation methods viz. tegra package of cultivation, farmers’ practice with high inputs, farmers’ practice with medium inputs and farmers’ practice with low inputs. the major features of the agronomic practices followed in tegra package and farmers’ practices are given in tables 1-3. to know about the farmers’ practice for transplant aman and boro rice cultivation, a questionnaire was prepared and collected from 20 farmers selected randomly from the village boira, mymensingh sadar, mymensingh and their cultivation practices such as seed collection, seedling raising technique, age of seedlings during transplanting, fertilizing dose and crop protection measures were noted. the experiments were laid out in a randomized complete block design (rcbd) with five replications with the unit plot size 10 m x 12 m to facilitate the use of rice transplanter. table 1. major features of agronomic practices for transplant aman rice cv. bbri dhan49 under tegra package and farmers’ practice cultivation practices tegra farmers’ practice quality of seeds foundation seed from bangladesh agricultural development corporation (badc) farmers’ own seed method of raising seedling tray method conventional method in nursery age of seedling (days) 18 27 method of transplanting transplanter manual spacing of transplanting 30cm x 14cm 25cm x 15cm crop protection advanced care as per the protocol care taken as and when necessary fertilizer dose* kgha-1 urea 185 200 tsp 120 120 mop 85 80 gypsum 70 45 91 improving yield of transplanted aman and boro rice through tegra package of cultivation table 2. major features of agronomic practices for boro rice cv. bbri dhan29 under tegra package and farmers’ practice cultivation practices tegra package farmers’ practice with high inputs farmers’ practice with medium inputs farmers’ practice with low inputs quality of seeds foundation seed from badc farmers’ own seed farmers’ own seed farmers’ own seed method of raising seedling tray method conventional method conventional method conventional method age of seedling (days) 30 45 45 45 method of transplanting transplanter manual manual manual spacing of transplanting 30 cm x 14 cm 25 cm x 15 cm 25 cm x 15 cm 25 cm x 15 cm crop protection advance care as per the protocol as and when necessary as and when necessary as and when necessary fertilizer dose* kgha-1 urea 296.4 393 280 167 tsp 103.74 130 104 72 mop (mop) 111.15 36 26 16 gypsum 59.28 112 82 56 * under tegra package grozin (zn fertilizer) @7.5 kg ha-1, boron @ 2.5 kg ha-1, megma (mg fertilizer) @ 15 kg ha-1 and thiovit ( fungicide) 7.5 kg ha-1 were applied. table 3. the protocol of plant protection measures taken in in transplant aman and boro rice under tegra package of cultivation riffit (preemergence herbicide) + lesar (systemic herbicide) (3-7 days of land preparation) 1st urea and thiovit (fungicide) (10-15 dat) virtako (insecticid e) (15-20 dat) 2nd urea and land drying (25-30 dat) 3rd urea, mop and virtako (insecticide ) (35-40 dat) amistertop (fungicide) (50-55 dat) score (fungicide ) (55-60 dat) plenum (insecticid e) (65-70 dat) amistertop (fungicide) + filia (fungicide) (70-75 dat), if diseases seen for tegra package, the seedlings were grown in tray with growing media of soil, ash and compost mixture (fig.1a) and seedlings were transplanted using mechanical transplanter with 30 cm x 16 cm spacing (fig. 1b). growing of seedlings in the media is required for machine transplanting of the seedlings for farmers’ practice, seeds were collected from the farmers and the seedlings were transplated manually with 25 cm x 15 cm spacing followed by the farmers. . intercultural operations like gap filling, irrigations etc. were done as and when necessary. at crop maturity data on yield contributing characters were collected. then grain yield was converted at 14% moisture and straws sun dried properly and then weighed. data collected on different parameters were statistically analyzed using software,(mstat) and mean comparisons were made by duncan’s multiple range test (gomez and gomez, 1984). 92 kader et al. fig.1 seedlings grown with special care in tray (a) and transplanting with rice transplanter (b) results and discussion yield and yield contributing characters of transplant aman rice cv. brri dhan49 the effect of tegra package of cultivation was not significant in panicle length, grain numbers panicle-1 , grain and straw yields (table 4). the superior growth parameters of the crop under tegra package of cultivation was reflected in terms of number of total tillers m2, number of effective tillers m-2 and 1000-grain weight (g). tegra package of cultivation produced significantly taller plant (103.8), higher number of total tillers hill-1 (429.35), effective tillers hill-1 (353.91) and 1000-grain weight (19.70 g) as compared to farmers’ practice. grain, straw and biological yields (grain yield + straw yield) of transplant aman rice cv. brri dhan49 under tegra package of cultivation were 5.88, 9.84 and 14.72, respectively as compared to farmers practice of 4.97, 6.24 and 11.21, respectively. the results revealed that the grain yield of rice cv. brri dhan49 increased by 18.3% under tegra package of cultivation as compared to farmers’ practice whereas straw yield increased by 57.69% .the higher grain and straw yields obtained under tegra package of cultivation as compared to farmers’ practice might be combined positive influence of all component technologies such as use of foundation seeds, better care of seedlings in the nursery, use of younger seedlings, better control of weeds and other pests, and use of balanced fertilization. ali et al. (1992) also reported superior yield performance of rice with younger seedlings. profitability of transplant aman rice cv. brri dhan49 as compared to farmers’ practice tegra package reduces the production cost of transplant aman rice by more than tk. 3000 as compared to the farmers’ practice (table 5). this higher production cost under farmers’ practice might be because of traditional way of transplanting and weeding requires more number of labors. thus the results reveal that tegra package of cultivation was not only superior in terms of yield but also incurred less cost of production as compared to farmers’ practices, besides increase in gross return (23%) and net return (400%) as compared to farmers’ practice (table 5). as a result, the benefit cost ratio of tegra package was higher (1.70) compared to that of farmers’ practice. yield and yield contributing characters of boro rice cv. brri dhan29 tegra package of cultivation method had significant effect in respect of yield and all yield contributing characters of boro rice. the result showed that among the four cultivation methods used in tegra package where produced the highest number of total tillers m-2, number of effective tillers m-2 and 1000 -grain weight (g) but farmers’ practice with high a b 93 improving yield of transplanted aman and boro rice through tegra package of cultivation inputs did not give better results in yield components. the superior growth and yield parameters, adoption of tegra package produced the highest grain yield (10.89 t ha-1) and straw yield (12.43 t ha-1). on the other hand, farmers’ practice with high inputs produced the lowest grain yield (6.17 t ha-1). the results reveal that tegra package of cultivation increased grain yield of boro rice cv. brri dhan29 by 80% as compared to farmers’ practices in general (average of farmers’ practice with high , medium and low input). the increase of straw yield of the crop under tegra package of cultivation was 38.73% from that of farmers’ practice with medium input. it is very clear from the results that tegra package of cultivation was much superior in producing grain and straw yield of boro rice cv. bbri dhan29 as compared to any of the three farmers’ practices.. among the treatments on farmers practices, medium input was better than that of high t and low input. profitability of boro rice cultivation under tegra package of cultivation as compared to farmers’ practices the production cost of boro rice cv. brri dhan29 under tegra package of cultivation was lower of taka 9000 and 4000 as compared to farmers’ practice with high and medium inputs, respectively. however, the production cost of the crop under tegra package of cultivation was a little higher than that of farmers’ practice with low inputs. the traditional way of transplanting and weeding under farmers’ practice required increased labor cost as compared to tegra package of cultivation. eventually, tegra package of cultivation produced the highest gross and net return as compared to the other farmers’ practices. the bcr of tegra package of cultivation was 2.20 which was only 1.18 under farmers’ practice with high input. similar results were also found by singh et al. (2005) who stated that the mechanical transplanting was most cost-effective providing maximum benefit cost ratio. conclusion from the results of the study it could be concluded that tegra package of rice cultivation is advantageous in terms of yield and cost of production of both transplant aman and boro rice under bangladesh context. the technology might play a very vital role in increasing rice production in the country if it is adopted at farmers’ level successfully at large scale and therefore requires more research in this area. table 4. yield and yield contributing characters of transplant aman rice cv. brri dhan49 as influenced by tegra package of cultivation and farmers’ practice treatments no. of total tillers m-2 no. of effective tillers m-2 no. of noneffective tillers m-2 no. of grains panicle-1 no. of sterile spikelet panicle-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1 ) tegra 429.35 a 353.91 a 78.06b 128.5 b 15.77 b 19.70 a 5.88 a 9.84 a 15.72a farmers’ practice 396.02 b 335.79 b 90.61a 134.7 a 20.90 a 17.60 b 4.97 b 6.24 b 11.21b lsd(0.05) 13.13 8.10 5.20 4.42 2.38 1.19 0.52 0.51 1.59 cv (%) 1.81 1.34 3.51 1.93 7.38 3.65 5.48 3.65 4.43 table 5. cost of production of transplant aman rice cv. brri dhan49 under tegra package of cultivation and farmers’ practice treatment total cost (tk ha-1) gross return (tk ha-1) net return (tk ha-1) benefit cost ratio (bcr) 94 kader et al. tegra package 121354.75 163680 43325.25 1.35 farmer’ practice 124645.50 133030 8384.50 1.07 table 6. yield and yield contributing characters of boro rice cv. brri dhan29 as influenced by tegra package of cultivation and farmers’ practices treatment no. of total tillers m-2 no. of effective tillers m-2 no. of noneffective tillers m-2 panicle length (cm) number of grains panicle-1 number of sterile sikelets panicle-1 1000grain weight (g) grain yield (tha-1) straw yield (tha-1) biological yield (t ha-1) tegra package 664.02 a 639.50 a 24.51 d 22.97a 137.9a 18.03a 22.24a 10.89a 12.435a 23.32a farmers’ practice (high input) 558.53 b 492.61 b 65.39 a 21.05c 106.6b 23.56b 21.09b 6.17c 7.927c 14.09c farmers’ practice (medium input) 549.83 b 504.19 b 45.25 c 21.71a 121.9b 20.23a 20.51b 6.88b 8.960c 15.84b farmers’ practice (low input) 541.52 b 499.44 b 39.08 b 20.91 b117.3c 18.93c 20.76b 6.39bc 8.125b 14.51c lsd(0.05) 36.85 36.65 6.78 0.501 5.13 1.33 1.18 1.09 0.257 1.25 cv (%) 4.04 4.34 9.79 1.49 3.02 4.79 3.54 6.96 2.56 5.06 table 7. cost of production of boro rice cv. bbri dhan29 under tegra package of cultivation and farmers’ practices treatments total cost (tkha-1) gross return (tk ha-1) net return (tk ha-1) benefit cost ratio (bcr) tegra method 124198.5 275340 151141.5 2.20 farmers’practice (high input) 133939.14 157764 23824.86 1.18 farmers’ practice (medium input) 128283.63 176160 45635.75 1.37 farmers’ practice (low input) 121126.49 163220 42093.51 1.34 reference ali, m. y., m. m. rahman and m. m. rahman. 1992. effect of seedling age and transplanting time on late planted aman rice. bangladesh j. train. develop. 5(2):75-89. brri, 2015a. rice database: rice area, production and yield in bangladesh. http://www.brri.gov.bd/site/page/f6e878c8-ceac-402d-9bed-6fb29a787428/ricedatabase_29 december 2015. brri, 2015b. modern rice cultivation (in bnagla) 18th edition. bangladesh rice research institute, gazipur 1701. pp. 7-10. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. 2nd. ed. john wiley and sons, new york. pp. 97-111. kamruzzaman, m. 2014. effects of invinsa on the yield of transplant aman rice cv. brri dhan49 under different dates of transplanting. m s thesis. department of agronomy, bangladesh agricultural university, mymensingh. p.40. 95 improving yield of transplanted aman and boro rice through tegra package of cultivation singh, g., t. r. sharma and c. w. bockhop. 1985, field performance evaluation of a manual rice transplanter. j. agric. engg. res. 32: 259-268. singh, k. k., a. s. jat, and s. k. sharma. 2005. improving productivity and profitability of rice (oryza sativa)-wheat (triticum aestivum) cropping system through tillage and planting management. the indian j. agril. sci. 75(7): 396-399. bangladesh agron. j. 2016, 19(2): 1-10 variations of growth parameters in some aromatic rice verities under salt stress md. habibur rahman1, md. abu naim1, md. abdul matin1, taufika islam anee1, md. amzad hossain2 and mirza hasanuzzaman1* 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2subtropical field science center, university of the ryukyus, 1 senbaru, nishihara city, okinawa 903-0213, japan *corresponding author: mhzsauag@yahoo.com key words: abiotic stress, growth, irrigated rice, nacl, salinity abstract a pot experiment with six aman rice varieties viz. brri dhan34, brri dhan38, binadhan-9, binadhan-13, kalijira and rajbhogh was conducted at the experimental shed of the department of agronomy, sher-e bangla agricultural university, dhaka during the period of junedecember, 2014 to investigate the effect of salinity on the growth, physiology and yield of some aromatic rice under different salt stress conditions. the experiment was carried out with five salt stress treatments viz. control (without salt), s25 (25 mm nacl), s50 (50 mm nacl), s75 (75 mm nacl) and s100 (100 mm nacl). salt stress significantly reduced the plant height, tiller hill-1 and leaves hill-1 of these varieties at all growth duration. among the varieties binadhan-9 and brri dhan38 performed better under saline condition. on the other hand, local variety kalijira did not perform well under saline condition. introduction soil salinity is a widespread environmental problem that has been found to affect over 77 million hectares or about 5% of the arable land worldwide (wang et al., 2001; athar and ashraf, 2009). due to climate change this salt affected areas are increasing day by day and assumed to affect 50% of cultivable land by the midth of 21st century (mahajan and tuteja, 2005). salinity is a major threat to crop productivity in the southern and south-western parts of bangladesh, where it is developed due to frequent flood by sea water of the bay of bengal. in bangladesh out of 2.85 million hectares of the coastal and off-shore areas about 0.833 million hectares are arable lands, which constitute about 52.8 percent of the net cultivable area in 13 districts (karim et al., 1990). introduction of irrigation with saline waters in those areas is another possible reason of the increasing content of salinity. salinity has adverse effects on plant growth and productivity. according to bray et al. (2000) salt stress can account for up to 50% yield reduction of the major crops. the nature of damage by salt stress is very complex as it causes both osmotic stress and ionic toxicity (hasanuzzaman et al., 2013). plants can respond and adapt to salt stress by altering their cellular metabolism and invoking various defense mechanisms (ghosh et al., 2011). the survival of plants under this stress condition depends on their abilities to perceive the stimulus, generate and transmit a signal, and initiate various physiological and biochemical changes (tanou et al., 2009; el-shabrawi et al., 2010). irrigated rice is well suited to control and even mitigate soil salinity (wopereis et al., 1998). but rice is a salt-sensitive crop and yield losses due to salinity can be substantial (asch et al., 1997). 2 rahman et al. aromatic rice varieties have gained significant market shares in the global rice trade. as a result, efforts are being undertaken in many countries to increase the production of this type of rice. there are evidences showing that the aromatic quality of these rice varieties varies depending upon the areas and locality of the rice cultivation (bradbury et al. 2008; hossain et al. 2008; nagarajan et al. 2010). considering the above mentioned perspectives, the present study was undertaken to investigate the effect of salinity on the growth performance of some aromatic rice varieties in relation to hyv ones. materials and methods the experiment was conducted at the experimental shed of the department of agronomy, sher-e-bangla agricultural university, dhaka (23.770155° n, 90.374358° e) during the period june-december, 2014. the soil of the experimental area belongs to the modhupur tract (aez no. 28). it was a medium high land with non-calcarious dark grey soil. the ph value of the soil was 5.6. six aromatic rice varieties including four hyvs and two lacal varieties were used in this experiment. the hyvs are: brri dhan34, brri dhan38, binadhan-9 and binadhan-13; and the local variities are: kalijira and rajbhogh. the experiment was laid out in a factorial randomized completely block design (rcbd) with three replications. there were 90 pots all together replication with the given factors. the salinity treatments were applied on 30 days after transplanting (dat), 45 dat, 60 dat and 75 dat. there were five salinity levels including control. salinity was induced by adding respected amount commercial nacl salt to the soil/pot as water dissolved solution. the salinity levels were c (fresh water), s25 (25 mm nacl), s50 (50 mm nacl), s75 (75 mm nacl) and s100 (100 mm nacl). seeds were soaked for 48 h and then washed thoroughly in fresh water and incubated for sprouting. the sprouted seeds were sown in the wet seedbed. the experimental pots were fertilized with 250, 110, 140, and 50 kg ha-1 n, p2o5, k2o, and s applied in the form of urea, triple super phosphate, murate of potash, and gypsum respectively. one-third of urea and the whole amount of other fertilizers were incorporated with soil at final pot preparation before sowing. rest of the nitrogen were applied in two equal splits one at 30 dat and second at 45 dat. thirty-day-old seedlings were uprooted carefully from the seedbed and transplanted in the respective pots at the rate of single seedling hill-1. all intercultural operations were done as per recommendation. the data obtained for different parameters was statistically analyzed following computer based software xlstat 2014 (addinsoft, 2016) and mean separation was done by least significant difference test (lsd) at 5% level of significance. results and discussion plant height plant height of different varieties was measured at different growing period (table 1). the highest plant height was found in brri dhan38 at all growth duration except 90 dat (97.98 cm at 30 dat, 108.41 cm at 45 dat, 110.51 cm at 60 dat and 113.71 cm). however, highest plant height also observed in brri dhan34 at 75 dat (112.33 cm) and at 90 dat (119.05 cm); in rajbhog at 30 dat (97.98 cm). the plant height of brri dhan34 at 90 dat and rajbhog at 60, 75, and 90 dat were statistically similar. this result was supported by hossain and sikdar (2009). plant height differed significantly at different salinity treatments (table 1). it was significantly greater at control than the other salinity levels. at 30 dat, plant height 3 variations of growth parameters in some aromatic rice verities under salt stress was the maximum at control (93.10 cm) which was statistically similar to that of 25 mm salinity (90.53 cm). the mimimum plant height (82.42 cm) was recorded at 100 mm salinity which was statistically similar to that of 75 mm (86.16 cm) salinity. the decreasing trends of the plant height were found with increasing salinity at 45 d and 90 dat. gradual decrease in plant height might be due to the nutrient unavailability caused by increased salinity or the inhibition of cell division or cell enlargement. salinity has direct effect in plant height. choi et al. (2003) observed that the plant height decreased in the 0.5% saline water in the soil. table 1. effect of variety and salinity level on plant height of rice at different days after transplanting variety plant height (cm) 30 dat 45 dat 60 dat 75 dat 90 dat brri dhan34 87.59bc 98.95bc 104.82bc 112.33a 119.05a brri dhan38 97.98a 108.41a 110.51a 113.71a 118.31ab binadhan-9 88.79bc 98.77bc 104.19bc 111.00a 113.91bc binadhan-13 85.56 c 95.90 c 100.32c 105.69b 110.27c kalijira 77.84d 87.20d 92.55d 99.41c 103.16 d rajbhogh 97.98a 101.88 b 108.77ab 109.34ab 117.85ab lsd (0.05) 4.18 4.90 5.11 5.06 5.01 salinity level c 93.10a 103.11a 108.85a 114.49a 119.38a s25 90.53ab 100.94a 105.6a 111.24a 116.28ab s50 89.02bc 98.73ab 104.27ab 110.35a 113.97bc s75 86.16cd 96.41bc 100.93bc 103.66 b 111.46cd s100 82.42d 93.41c 97.96c 103.16b 107.70d lsd (0.05) 3.82 4.48 4.68 4.63 4.58 cv (%) 6.49 6.81 6.77 6.39 6.04 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd. the combined effect of salinity and varieties on plant height was significant at p≤0.05 (table 2). plant height generally decreased w ith the increasing level of salinity. in interaction effects plant height was highest at control plants of brri dhan38 and lowest at 100 mm salinity levels of kalijira variety. similar results were recorded by khandakar and alim (2004). chen et al. (1989) reported that plant height seriously decreased by salinity. tillers hill-1 there was a significant variation found in number of tillers hill-1 due to varietal variation (table 3). the highest number of tillers hill-1 was found at 30 dat (4.76), at 75 dat (25.27) and at harvest (20.51) in case of binadhan-9; at 45 dat (10.13) and at 60 dat (16.03) in case of brri dhan38 and at 45 dat (10.03) in case of binadhan-13. however, the lowest number of tillers hill-1 observed at 30 dat (3.61) in brri dhan34; at 45 dat (7.14), 60 dat (12.59), 90 dat (13.47) and harvest (12.02) in kalijira; at 75 dat (18.66) in binadhan-13. 4 rahman et al. table 2. the combined effects of salinty and aman rice varieties on plant height at different days after trasplanting variety salinity treatment plant height (cm) 30 dat 45 dat 60 dat 75 dat 90 dat brri dhan34 c 93.07a-g 103.07abc 109.83a-f 114.43a-e 122.73abc s25 89.90c-h 100.63bc 106.50a-f 112.67a-f 122.07abc s50 89.13 c-h 99.13bcd 106.13a-f 112.43a-f 119.73a-e s75 83.80g-k 96.40cde 101.87d-i 111.60a-f 118.30a-e s100 82.07 h-l 95.53c-f 99.77 f-j 110.50a-g 112.40c-i brri dhan38 c 101.90a 112.00a 116.73a 118.10a 124.50a s25 101.00ab 112.30a 113.70ab 118.10a 120.60a-d s50 97.60abc 107.63ab 111.27a-e 116.53abc 117.30a-f s75 96.63a-d 105.77abc 106.53a-f 109.50a-h 115.30a-g s100 92.80a-g 104.33abc 104.30 b-g 106.23b-i 113.83a-h binadhan-9 c 91.80b-g 101.90abc 107.03a-f 114.73a-d 118.40a-e s25 89.17c-h 99.37bcd 104.37b-g 114.93a-d 118.20a-e s50 88.83c-h 98.40bcd 104.60 b-g 114.34a-e 116.53a-f s75 88.43c-h 98.47bcd 103.90b-h 106.53b-i 109.50d-j s100 85.73f-j 95.73c-f 101.07d-i 104.47d-i 106.90f-k binadhan13 c 90.43c-h 100.40bc 106.07a-f 116.97ab 116.03a-g s25 89.67c-h 99.63bc 103.70c-h 103.20e-i 113.83a-h s50 86.8e-i 97.33b-e 100.40e-j 110.23a-g 110.00d-j s75 85.47f-j 95.33c-g 98.90f-k 98.53hij 108.97e-j s100 75.43kl 86.80e-h 92.53h-k 99.53g-j 102.53ijk kalijira c 85.70f-j 95.43c-g 100.83e-j 108.50a-h 105.27g-k s25 78.10 i-l 88.50d-h 93.17h-k 105.23c-i 102.97h-k s50 77.30j-l 85.03fgh 91.80ijk 95.87ij 99.60jk s75 74.77kl 84.53gh 89.4jk 90.97j 102.97h-k s100 73.27l 82.50 h 87.50k 96.47ij 97.47 k rajbhogh c 95.73a-e 105.83abc 112.60abc 114.23a-e 124.13ab s25 95.37a-e 105.23abc 112.30a-d 113.20a-e 117.70a-f s50 94.40a-f 104.83abc 111.40 a-e 112.67a-f 117.27 a-f s75 87.87d-h 97.93bcd 104.97b-f 104.83 d-i 117.07a-f s100 85.23f-j 95.5c-f 102.57b-i 101.77f-j 113.07b-i lsd (0.05) 9.36 10.96 11.44 11.33 11.22 cv (%) 6.49 6.81 6.77 6.39 6.04 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd. 5 variations of growth parameters in some aromatic rice verities under salt stress table 3. effect of variety and salinity level on number of tillers hill-1 of rice at different days after transplanting variety number of tillers hill-1 30 dat 45 dat 60 dat 75 dat 90 dat at harvest brri dhan34 3.61e 7.52c 14.22c 20.02d 16.28d 15.36d brri dhan38 4.76c 10.13a 16.03a 21.78c 17.56c 17.38c binadhan-9 5.52a 9.51b 15.11b 25.27a 20.69a 20.51a binadhan-13 5.14b 10.03a 13.68c 18.66e 14.91e 14.07e kalijira 3.98d 7.14d 12.59d 23.54b 13.47f 12.02f rajbhogh 4.70c 9.57b 13.96c 20.02d 18.37b 19.31b lsd (0.05) 0.20 0.41 0.65 0.77 0.73 0.67 salinity level c 7.34a 14.52a 20.21a 26.64a 21.45a 19.54a s25 6.32b 11.98b 18.37b 24.76b 19.53b 18.29b s50 4.61c 8.96c 13.98c 20.58c 17.03c 16.41c s75 2.98d 5.66d 10.50d 17.52d 14.21d 14.78d s100 1.83e 3.79e 8.27e 14.60e 12.17e 13.20e lsd (0.05) 0.19 0.38 0.59 0.71 0.66 0.61 cv (%) 6.21 6.38 6.25 5.11 5.92 5.62 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd. application of salt decreased the number of tillers hill-1 of rice varieties (table 3). it was significantly greater at the control than in other salinity levels. the highest number of tillers hill-1 was recorded in control at all growing period (7.34 at 30 dat, 14.52 at 45 dat, 20.21 at 60 dat, 26.64 at 75 dat, 21.45 at 90 dat and 19.54 at harvest. with the increasing salinity levels the number of tillers hill-1 drastically reduced. so, the lowest number of tillers hill-1 found in 100 mm salinity level at all growth periods. it was observed that number of productive tillers hill-1 decreased with increase in salinity levels (heenan and lewin, 1998 and hasamuzzaman et al., 2009). the interaction effect of salinity levels and cultivars in relation to the number of tillers hill-1 was found significant (p ≤ 0.05) (table 4) at all growing periods. the highest number of tillers hill-1 was obtained from binadhan-9 at control condition with the increase of growing period (8.33 at 30 dat, 17.30 at 45 dat, 22.43 at 60 dat, 31.55 at 75 dat, 25.17 at 90 dat and 23.02 at harvest. but sometimes brri dhan38 at 30 dat and binadhan-13 at 30 dat obtained highest tillers hill-1. the lowest number of tillers hill-1 was obtained from kalijira at 100 mm salt treatment with the increase of growing period (1.17 at 30 dat, 3.11 at 45 dat, 7.51 at 60 dat, 10.43 at 75 dat, 8.45 at 90 dat and 8.29 at harvest). islam et al. (2007) also reported that increasing salinity levels negatively affects the number of tillers hill-1. 6 rahman et al. table 4. the combined effects of salinty and aman rice varieties on no. of tillers hill1 at different days after trasplanting variety salinity treatment number of tillers hill-1 30 dat 45 dat 60 dat 75 dat 90 dat at harvest brri dhan34 c 6.16c 13.30c 20.63b 25.85de 20.52de 18.97cd s25 5.28d 10.37efg 18.64cd 23.13f 18.98ef 16.33gh s50 3.15f 6.57j 13.45fg 19.8hi 17.183ghi 15.22hi s75 2.30g 4.04lm 11.40hi 17.50 j 13.43lm 13.43jkl s100 1.16h 3.25lmn 7.00k 13.70k 11.30no 12.88jkl brri dhan38 c 8.00a 14.70b 20.54b 27.92bc 22.40bc 20.32bc s25 7.08b 13.40c 19.50bc 25.63e 19.66ef 18.46def s50 5.11d 10.39ef 17.26de 21.80fg 18.46fg 17.52defg s75 2.26g 7.02j 12.28gh 18.61ij 14.56kl 16.22gh s100 1.33h 5.16k 10.59ij 14.95k 12.73mn 14.37ij binadhan-9 c 8.33a 17.30a 22.43a 31.55a 25.517a 23.02a s25 7.01b 11.54d 19.72bc 29.32b 23.63b 22.53a s50 5.18d 9.45ghi 13.57fg 25.51e 19.51ef 20.85b s75 4.05e 5.18k 10.37ij 22.53f 18.22f-i 18.88cde s100 3.04f 4.08l 9.46j 17.44j 16.60ij 17.29fg binadhan13 c 8.29a 14.69b 20.23b 23.37f 18.55fg 17.21fg s25 7.17b 13.39c 17.52de 22.40f 16.82hij 16.66gh s50 5.12d 9.44hi 13.55fg 19.47hi 15.41jk 13.76ijk s75 3.10f 8.54i 9.56j 14.72k 13.31lm 12.37kl s100 2.05g 4.08l 7.53k 13.35k 10.50o 10.34m kalijira c 6.13c 11.58d 17.71de 22.40f 18.67g 15.22hi s25 5.27d 9.57fgh 16.53e 20.54gh 16.65ij 14.13ij s50 5.10d 7.45j 11.47hi 13.49k 13.22lm 12.07l s75 2.28g 4.03lm 9.72j 11.40l 10.36o 10.33m s100 1.17h 3.11mn 7.51k 10.43l 8.45p 8.29n rajbhogh c 7.17b 15.40b 19.73bc 28.73bc 23.08bc 22.49a s25 6.21c 13.67c 18.28cd 27.55cd 21.46cd 21.60ab s50 4.00e 10.50e 14.60f 23.33f 18.43fgh 19.01cd s75 3.90e 5.18k 9.66j 20.40gh 15.41jk 17.45efg s100 2.25g 3.06n 7.54k 17.72j 13.48lm 16.02gh lsd (0.05) 0.46 0.93 1.45 1.73 1.63 1.51 cv (%) 6.21 6.38 6.25 5.11 5.92 5.62 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd number of leaves hill-1 number of leaves of different rice varieties differed significantly due to salinity (table 5). brri dhan34 produced the highest number of leaves at all growth duration except 7 variations of growth parameters in some aromatic rice verities under salt stress 30 dat (155.03 at 45 dat, 163.62 at 60 dat, 145.18 at 75 dat and 122.65 at 90 dat). however, the lowest number of leaves was recorded in binadhan-9 at 30 dat (77.09), at 45 dat (91.83) and in binadhan-13 at 75 dat (94.57), at 90 dat (94.32). table 5. effect of variety and salinity level on number of leaves hill-1 of rice at different days after transplanting variety number of leaves hill-1 30 dat 45 dat 60 dat 75 dat 90 dat brri dhan34 111.84b 155.03a 163.62a 145.18a 143.08a brri dhan38 116.95a 133.65b 147.66b 122.47c 122.65b binadhan-9 77.09 e 91.83e 118.63d 107.97d 116.92b binadhan-13 85.15d 116.05d 126.76c 94.57e 94.32c kalijira 92.35c 122.55c 113.62d 94.46e 99.31c rajbhogh 92.15c 112.97d 153.95b 136.30b 137.46a lsd (0.05) 4.88 6.04 7.04 6.19 6.22 salinity level c 114.64a 156.40a 183.22a 159.84a 156.92a s25 105.30b 136.75b 158.83b 135.33b 135.80b s50 95.24 c 120.29c 138.96c 116.96c 118.26c s75 86.86d 89.17d 114.37d 92.68d 100.67d s100 77.56 e 107.46e 91.47e 79.33e 83.14e lsd (0.05) 4.45 5.52 6.43 5.65 5.68 cv (%) 6.97 6.78 7.02 7.26 7.16 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd. different salinity treatments affected the number of leaves hill-1 significantly throughout the growing period. salinity treatment reduced the number of leaves hill-1 compared to control (table 5). the highest number of leaves recorded at control from the beginning to end (114.64 at 30 dat, 156.40 at 45 dat, 183.22 at 60 dat, 159.84 at 75 dat and 156.92 at 90 dat). with the increase of salinity level the number of leaves hill-1 reduced. the lowest number of leaves hill-1 observed in 100 mm saline condition at all growing period. this result showed that number of leaves hill-1 decreased gradually with the increasing salinity levels. similar results were reported by dabnath (2003). sharp decreases in number of leaves hill-1 was observed in response to salt stress, compared to the control at 30, 45, 60, 75 and 90 dat for six aman rice varieties (table 6). the highest number of leaves hill-1 was recorded in brri dhan34 at all dat(127.81 at 30 dat, 194.74 at 45 dat, 205.01 at 60 dat, 183.06 at 75 dat and 184.08 at 90 dat) during control condition. but after the application of salt at different concentrations, the number of leaves hill-1 was reduced. kalijira showed lowest number of leaves hill-1 at 100 mm saline condition (70.85 at 45 dat, 68.57 at 60 dat, 55.02 at 75 dat and 62.28 at 90 dat) which were similar in case of binadhan-13 at 100 mm saline codition during 45 dat and in case of binadhan-9 at 100mm saline during 75 dat. this results are supported by alamgir and ali (2006). 8 rahman et al. table 6. the combined effects of salinty and aman rice varieties on number of leaves hill-1 at different days after trasplanting variety salinity treatment number of leaves hill-1 30 dat 45 dat 60 dat 75 dat 90 dat brri dhan34 c 127.81a 194.74a 205.01a 183.06a 184.08a s25 125.59a 147.57cd 172.60bc 161.33bc 163.94b s50 108.12cd 147.23cd 166.36bc 148.25cd 137.36de s75 104.72c-f 144.06cd 163.71cd 121.34e 130.63efg s100 92.95g-k 141.54de 110.41jk 111.94e 99.41j brri dhan38 c 131.79a 175.87b 178.91bc 165.23b 156.25bc s25 127.44a 140.44de 178.00bc 145.44d 153.54bc s50 121.58ab 128.66ef 173.28bc 142.17d 147.13cd s75 114.21bc 122.83ef 113.68ijk 86.90fg 84.24k s100 89.72h-l 100.44i-l 94.43lm 72.61h 72.09klm binadhan-9 c 86.59i-m 128.45ef 164.19cd 162.42b 161.72b s25 83.74j-n 108.15hij 145.84ef 117.16e 122.36fgh s50 83.32k-n 95.92jkl 124.43g-j 109.52e 117.68f-i s75 66.15pq 64.25m 87.89mn 78.92gh 113.73lm s100 65.64pq 62.36m 70.79o 71.80h 69.10ef binadhan13 c 122.87ab 145.69cd 181.34b 142.39d 131.23ij s25 94.27f-j 140.18de 150.44de 115.55e 106.08kl s50 78.23mno 115.75fgh 119.65h-k 87.46fg 79.50k s75 67.67opq 109.53ghi 104.40kl 78.93gh 79.71l s100 62.72q 69.10m 77.95no 48.50i 75.11klm kalijira c 105.72cde 157.06c 170.20bc 139.30d 146.71cd s25 99.96defgh 145.42cd 134.74e-h 112.86e 117.07ghi s50 96.20efghi 128.21ef 111.17ijk 93.07f 99.28j s75 85.03j-n 111.23ghi 83.43mno 72.07h 71.20kl s100 74.83nop 70.85m 68.57o 55.02i 62.28m rajbhogh c 113.05bc 136.57de 199.69a 166.61b 161.52m s25 100.83d-g 138.71de 171.36bc 159.62bc 151.81b s50 83.97j-n 105.97h-k 138.89efg 121.27e 128.63bc s75 83.38j-n 92.88l 133.14fgh 117.92e 124.51efg s100 79.52lmn 90.72k 126.67ghi 116.09e 120.83e-h lsd (0.05) 10.92 13.53 15.76 13.86 13.93 cv (%) 6.97 6.78 7.02 7.26 7.16 values in a column with different letters are significantly different at p ≤ 0.05 applying lsd conclusion despite rice var. brri dhan38 produced the tallest plant under control conditions where binadhan-9 showed the maximum number of tillers hill-1 and brri dhan34 highest number of leaves hill-1 at all the treatments. the overall growth performance of binadhan-9 and brri dhan38 was better under saline conditions than the other varieties. moreover, hyvs showed better growth performance than local varieties under salt stress conditions. 9 variations of growth parameters in some aromatic rice verities under salt stress references addinsoft, 2016. xlstat v. 2016.04.32525: data analysis and statistics software for microsoft excel. addinsoft; paris, france. alamgir, a. n. m. and m. y. ali. 2006. effects of nacl salinity on leaf characters and physiological growth attributes of different genotypes of rice (oryza sativa l.). bangladesh j. bot. 35(2): 99-107. asch, f., m. dingkuhn and k. dörffling. 1997. physiological stresses of irrigated rice caused by soil salinity in the sahel. in: k. m. miezan, m. c. s. wopereis, m. dingkuhn, j. deckers and t. f. randolph (eds.). irrigated rice in the sahel: prospects for sustainable development. west africa rice development association, bp 2551, bouake 01, côted’ivoire. pp. 247-273. athar, h. r. and m. ashraf. 2009. strategies for crop improvement against salt and water stress: an overview. in: m. ashraf, m. ozturk, h. r. athar (eds.). salinity and water stress: improving crop efficiency. springer, the netherlands. pp. 1-16. bradbury, l. m. t., s. a. gillies, d. j. brushett, d. l. e. waters and r. j. henry. 2008. inactivation of an aminoaldehyde dehydrogenase is responsible for fragrance in rice. plant mol. biol. 68: 439-449. bray, e. a., j. bailey-serres and e. weretilnyk. 2000. responses to abiotic stress. in: b. buchanan, w. gruissem, r. jones (eds.). biochemistry and molecular biology of plants. american society of plant physiology, rockville. pp. 1158-1203. chen, t., k. h. kreeb, h. richter and t. m. kirckicy. 1989. combined effect of drought and salt stress on growth hydration and pigment composition in gossipium hirsutum l. structural and functional response to environment stress: water shortage. spb academic publishing. pp. 165-177. choi, w. y., k. s. lee, j. c. ko, s. y. choi and d. h. choi. 2003. critical saline concentration of soil and water for rice cultivation on a reclaimed saline soil. korean j. crop sci. 48:238-242. dabnathh, s. c. 2003. effect of salinity on growth and yield in three mustard genotypes. ms thesis, department of crop botany, bangladesh agril. univ., mymensingh. el-shabrawi h., b. kumar, t. kaul, m. k. reddy, s. l. singla-pareek and s. k. sopory. 2010. redox homeostasis, antioxidant defense, and methylglyoxal detoxification as markers for salt tolerancein pokkali rice. protoplasma 245: 85-96. ghosh, n., m. k. adak, p. d. ghosh, s. gupta, d. n. s. gupta and c. mandal. 2011. differential responses of two rice varieties to salt stress. plant biotechnol. rep. 5: 89-103. hasanuzzaman, m., k. nahar and m. fujita. 2013. plant response to salt stress and role of exogenous protectants to mitigate salt-induced damages. in: p. ahmad, m. m. azooz and m. n. v. prasad (eds.). ecophysiology and responses of plants under salt stress. springer, new york. pp. 25-87. hasanuzzaman, m., m. fujita, m. n. islam, k. u. ahamed and k. nahar. 2009. performance of four irrigated rice varieties under different levels of salinity stress. int. j. integr. biol. 6(2): 85-89. heenan, d. p. and l. g. lewin. 1998. salinity tolerance in rice varieties at different growth stages. aust. j. exp. agric. 28(3): 343-349. hossain, m. f. and m. s. i. sikdar. 2009. performance of aromatic rice varieties under different transplanting date in aman season. j. agrofor. environ. 3(1): 41-44. http://www.sciencedirect.com/science/article/pii/s0378429010000419#bib4 http://www.sciencedirect.com/science/article/pii/s0378429010000419#bib4 10 rahman et al. hossain, m. b., m. o. islam and m. hasanuzzaman. 2008. influence of different nitrogen levels on the performance of four aromatic ricevarieties. int. j. agri. biol. 10: 693–6. islam, m. z., m. a. baset mia, m. r. islam and a. akter. 2007. effect of different saline levels on growth and yield attributes to mutant rice. j. soil nat. 1(2): 18-22. karim, z., s. g. hussain and m. ahmed. 1990. salinity problems and crop intensification in the coastal regions of bangladesh. barc, soil publ. 3(3):3-6. khandker, s. and a. m. alim. 2004. annual report 2004-2005. bangladesh jute research institute (bjri), dhaka, bangladesh. p.50. mahajan, s. and n. tuteja. 2005. cold, salinity and drought stresses: an overview. arch. biochem. biophys. 444: 139-158. nagarajan, s., s. v. k. jagadish, a. s. hari prasad, a. k. thomar, a. anand, m. pal and p. k. agarwal. 2010. local climate affects growth, yield and grain quality of aromatic and non-aromatic rice in northwestern india. agric. ecosys. environ. 138: 274-281. tanou, g., c. job, l. rajjou, e. arc, m. belghzi, g. diamantidis, a. molassiotis and d. job. 2009. proteomics reveal the overlapping roles of hydrogen peroxide and nitric oxide in the acclimation of citrus plants to salinity. plant j. 60: 795-804. wang, w., b. vinocur, o. shoseyour and a. altman. 2001. biotechnology of plant osmotic stress tolerance: physiological and molecular considerations. acta hortic. 590: 286-292. wopereis, m. c. s., j. ceuppens, b. boivin, a. m. ndiaye and a. kane. 1998. preserving soil quality under irrigation in the senegal river valley. nethreland j. agril. sci. 46: 97-107. microsoft word 9. baj-231_revised.docx bangladesh agron. j. 2016, 19(1): 67-79 effect of balanced fertilization in puddled rice on the productivity of lentil in rice-fallow system under zero tillage p.k. bandyopadhyay1*, k.c. singh1, k. mondal1, r. nath2, n. kumar3 and s.s. singh3 1dept. of agril. chemistry and soil sci., bidhan chandra krishi viswavidyalaya, mohanpur, nadia, west bengal, india 2department of agronomy, bidhan chandra krishi viswavidyalaya, mohanpur, nadia, west bengal, india 3indian institute of pulse research, kanpur-208024, india *corresponding author: pkb_bckv@rediffmail.com key words: stubble residues, mulch, moisture stress, leaf relative water content, water use efficiency abstract lentil (lens culinaris medik) predominantly grows under rainfed conditions under residual soil moisture in most of the rice-fallows in india with low productivity. imbalanced npk (n1), recommended dose of npk (n2) and recommended npk + 10 t ha-1 fym (n3) were applied in kharif rice (var. iet 4786) through consecutive three years (2011-2013). two lentil varieties viz. asha (b-77) and subrata (wbl-58) were sown after rice under zero tillage conditions keeping standing residues and mulch through utilizing residual moisture and nutrients. zero tillage with straw mulch (zt-m) in both lentil varieties conserved 12-20% more water than residue removal (zt) and 7-10% more than standing residue (zt-h), respectively. during flowering (60 das) surface soil (0-5 cm) of zt attained 0.8 mpa as compared to 0.2 and 0.1 mpa for zt-h and zt-m, respectively. soils with n3 stored more water and depleted lesser than n2 and n1 which produced higher biomass, leaf relative water content (rwc) and chlorophyll content. soil thermal variation in zt-m tends to proliferate root and nutrient uptake that increased 19 and 14% more yield and 25 and 15% more water use efficiency (wue) than zt-h and zt. both subrata and asha performed well under zero tillage conditions. zero tillage and nutrient management had an effect on soil microbial biomass carbon (smbc) and dehydrogenase activity as zt < zt-h < zt-m and n3 > n2 > n1. proper technology with application of zero tillage may explore the possibility of growing lentil crops in rice fallows during postrainy season utilizing carry-over soil moisture and residual soil fertility. introduction lentil is an annual, most promising cool season grain legume in india, ranks first in the world in respect of production, accounting for approximately 27% of the world’s production with a national average productivity of 1000 kg ha-1 under rainfed conditions. in west bengal, lentil occupies an area of 0.065 m ha area with a productivity of 763 kg ha-1 (fao, 2010), grows under rainfed conditions on residual soil moisture during pre winter (from late november to early december) and faces soil moisture deficit and high temperature at reproductive growth stage (gupta and bhowmick, 2005). however, information on actual moisture needs and time and intensity of stress occurs using post-rainy season crops with residual soil moisture in rice fallows are very scarce. if ploughing is done after harvest of rice to remove stubbles, sowing of lentil is delayed which in turn produce water deficit conditions and that leads to abortion of flowers and young pods and prevents seed filling (lal et al., 1988; materne and reddy, 2007). nevertheless, all physiological processes in plants are directly affected by water availability (sarker et al., 2005). the key objective is to tap residual soil moisture and leftover fertility of previous crop by the succeeding lentil crop. if balanced fertilization is done 68 bandyopadhyay et al. in rainfed puddled rice and crop residues are retained on the soil surface in combination with suitable planting techniques of lentil, it may alleviate terminal drought condition in crops by conserving soil moisture and bring overall improvement in resource management (ghosh et al., 2010). no till or zero tillage is an important component of conservation agriculture to produce crops at low cost with profound effect on natural resources such as water and soil (gangwar et al., 2006). this system is very effective in minimizing soil and crop residue disturbance, controlling soil evaporation, minimizing erosion losses, sequestering carbon in soil and reducing energy needs (kumar et al., 2011). therefore, in the present study, the objective was to evaluate the effect of balanced fertilization in puddled rice on moisture storage, stress, microbial diversity and productivity of lentil in rice-fallow cultivated under zero tillage with residue management. materials and methods experimental site and treatments imposed field experiments were conducted in 2011-12 to 2013-14 in rice fallow area after short duration (120 days) kharif rice (var. iet 4786) with lentil (var. b-77, asha and wbl-58, subrata) under zero tillage in nadia district of west bengal (22.99˚n, 88.43˚e, 13 m msl). the climate is hot, humid subtropics with an average annual rainfall of approximately 1470 mm and mean annual minimum and maximum temperatures of 18 and 35 ºc, respectively. on average, 35 mm scattered rainfall occurs during november to march and 11 to 25 ºc temperatures (min. and max.) and 50-57% rh prevail at the pick growth period (table 1). the soil is hyperthermic (aeric haplaquept, us soil taxonomy, soil survey staff, 2003) and clay loam in texture (table 2), neutral in ph, medium to high in bulk density with low organic matter contents. three different nutrient managements were applied for ricei) farmers’ practice (n1, 40:20:20 as n: p2o5 k2o), ii) recommended dose of n:p2o5:k2o = 80:40:40 (n2) and iii) recommended dose of n:p2o5:k2o = 80:40:40 + 10 t ha-1 fym (n3), respectively. the rice crop was transplanted on 21st july with seedling age 21 days in rows and was harvested on 1st week of november in 2011, 2012 and 2013, respectively. seven days after harvesting of rice, the land was used for lentil cultivation under zero tillage system. no fertilizer was applied for lentil, however, 2% dap was sprayed at vegetative stage (30 days old). the experiment was laid out in factorial strip plot design with three residue management labels and three replications with the individual plot size being 5 m × 4 m. three residue management under zero tillage assigned were: (i) zero tillage with residue removal (zt): seeds were sown @ 30 kg ha-1 by drilling 65 mm with hand hoe in between two rice stubbles (6-8 cm height) of equal spacing. (ii) zero tillage with tall stubble residue (zt-h): seeds were sown @ 30 kg ha-1 by drilling 65 mm with hand hoe in between two rice stubbles (20 cm height) of equal spacing. (iii) zero tillage with residue removal but straw mulching (zt-m): seeds were sown @ 30 kg ha-1 by drilling 65 mm with hand hoe in between two rice stubbles (6-8 cm height) of equal spacing then application of surface straw mulch to cover the land. stubble cutting height of 6-8 and 20 cm stubble left 0.20 and 0.35 kg m-2 (~2.0 and 3.5 t ha-1) residue that retained in the lentil field under zt and zt-h systems. on the other hand, 0.45 kg m-2 (~4.5 t ha-1) rice straw mulch was applied (zt-m) on 0.20 kg m-2 (~2.0 t ha-1) residue left by normal cutting height (6-8 cm). 69 effect of balanced fertilization in puddled rice on the productivity of lentil table 1. meteorological parameters during rice-lentil cropping system (pooled data of 20112012 to 2013-2014) temperature (oc) month max min rainfall (mm) rh (%) evapo-transpiration rate (mm d-1) bright sunshine hour july 32.7 26.4 198.7 79.6 2.4 4.8 august 32.0 26.2 388.2 81.5 2.1 4.3 september 32.8 25.9 268.5 77.7 2.2 5.0 october 32.6 23.5 112.8 66.7 2.2 6.8 november 29.8 17.3 9.4 55.7 1.5 7.3 december 25.9 12.5 2.4 58.4 1.0 5.9 january 24.2 11.1 2.5 57.4 1.1 5.6 february 28.8 12.7 9.5 50.3 1.5 6.2 march 32.8 17.5 10.9 47.1 2.7 8.2 table 2. physical properties of soil of the experimental soils soil depth (cm) soil properties 0-5 5-10 10-20 20-30 30-40 40-60 sand (%) 35 35 33 35 31 38 silt (%) 28 28 29 27 27 26 clay (%) 37 37 38 38 42 36 textural class clay loam bulk density (g cm-3) 1.42 1.51 1.60 1.65 1.70 1.73 whc (%) 68 67 64 62 60 60 saturated hydraulic conductivity (cm h-1) 0.12 0.12 0.07 0.03 0.01 0.01 soil moisture content (%) at fc and wp 34, 15 34, 15 31, 12 28, 12 28, 12 28, 12 soil moisture studies soil moisture measurement was done by using core sampler of 4 cm in diameter and a length of 3 cm for the surface soil (0-5 cm) and by a pr2/6 profile probe soil moisture meter for 5-10, 10-20, 20-30, 30-40 and 40-60 cm depths at 7 days interval in three years. the periodic stress coefficient ks was determined as stated by allen et al. (1998) using soil moisture depletion study. the actual water use (awu) throughout the growing season of lentil was computed using the water balance relationship as: ...... (1) where, dr = soil moisture depletion in the root zone (40 cm) from sowing to the end of the season (mm); p = effective precipitation in the crop growth season (mm), collected from the nearby meteorological observatory. plant parameters the relative water content (rwc) of leaves was estimated at vegetative [30 days after sowing (das), flowering (60 das) and pod formation (90 das) stages by the method of barrs and weatherly (1962) by using the following equation: 70 bandyopadhyay et al. 100 dwtw dwfwrwc     ...... (2) where, tw = turgid weight, dw = dry weight and fw = fresh weight of leaves. maximum above ground dry biomass was measured at vegetative, flowering and at pod formation stages. yield and water use efficiency the lentil crops were harvested manually by uprooting at grain maturity stage (15% moisture content) on the second week of march. the water use efficiency (wue, kg ha-1 mm-1) was calculated using lentil seed yield in relation to actual water used from sowing to harvesting as: used water total yieldseed flentilwue  ...... (3) all statistical analyses were performed using ibm, spss v. 20.0 (spss inc. chicago, il, usa) for windows. nutrients and residue effects on measured variables were performed by analysis of variance (anova) through the general linear model (glm) using factorial strip plot design. results and discussion soil moisture dynamics temporal soil moisture distribution throughout the profile indicated a decrease in trend from sowing to harvesting under different residues and nutrient management practices (fig. 1). no significant variations of spatial and temporal moisture content were observed in plots with asha (b-77) and subrata (wbl-58). results showed that treatments with zt-m dried slower than zt-h and zt, respectively, however, no significant variations were observed under residual effect of nutrient management in rice. the rate of diminution soil moisture with time was more in surface (0-5 cm) soils of zt compared to zt-h and zt-m (fig. 1) indicating more evaporation loss as the exposed soil is venerable to evaporation (kar and kumar, 2009). during initiation of flowering the depletion was observed more in zt and less in zt-m; more in n1 as compared to n2 and n3 treatments, however, no differences among asha and subrata in tillage and nutrients management was observed. the distribution of moisture content of 1m profile with depth and time during the lentil growth period (fig. 1) shows that at any suction value, the volumetric moisture retention is the lowest at the surface and is the highest at the bottom most layer of the soil profile. it was also evidenced that a hydraulic gradient existed upward in the root zone indicating an upward capillary flux might have occurred from deeper soil layers. however, a reduction in soil moisture at 20-30 cm layer forming neckline (fig. 1), signifies mechanical impediment that might restricts upward contribution. the critical soil moisture, worked out from water availability decreased with increasing depth with a mean value of 22%. at surface soil (0-5 cm), zero tillage with straw mulch (zt-m) conserved 3-8% higher amount of moisture as compared to zero tillage with residue (zt-h) or without (zt) (data not shown). there was a sharp fall in soil moisture storage from vegetative to pod formation stages (table 3). zero tillage controls the stored soil moisture significantly at the trend of zt-m > zt-h > zt. residue with zt-m and zt-h stored 12-20% and 4-13% more water than zt. nonetheless, zt-m stored 7-10% more than zt-h, respectively. favourable hydrothermal 71 effect of balanced fertilization in puddled rice on the productivity of lentil regime due to mulching encouraged root growth and thus enhanced utilization of conserved soil moisture by rainfed crops (acharya and sharma, 1994). soil fertility levels also modified soil moisture storage significantly as n3 > n2 > n1 where n3 and n2 stored 9-16% and 4-13% more moisture than n1. soils under variety asha (b-77) stored significantly higher soil moisture (6-11%) as compared to subrata (wbl-58). the actual water used by lentil crop in the root zone (0-40 cm) was significantly affected by zero tillage where zt > zt-h > zt-m, amounting 19.5, 18.8 and 18.7 cm, respectively (table 4). on average, 19.0 cm water was actually used by lentil crop under zero tillage systems. the finding is in close agreement with 18.5 cm (tuti et al., 2012) in humid tropical and sub-tropical climate. lower profile water change (depletion) under lentil in zt-m was due to less or no evaporation from soil surface throughout the growing period as compared to zt-h and zt, respectively (table 4). the lentil crop received 12.9 mm mean effective precipitation during the cropping seasons. an artificial barrier with straw and standing stubbles may help for slow and steady entry of water and thus may reduce drainage loss. nutrient management in rice also significantly affected the actual water use as n1 > n2 > n3 indicating the effect of continuous application of fym on soil moisture dynamics. 72 bandyopadhyay et al. fig. 1. distribution of moisture within soil profile at critical growth periods under different nutrient and residue management practices (pooled data of three years with var. asha) table 3. soil moisture storage (cm) at critical stages under different nutrient and residue management practices asha subrata mean residue v f pf v f pf v f pf zt 8.79 7.43 5.78 8.12 6.68 4.65 8.46 7.05 5.21 zt-h 9.50 7.61 6.28 8.38 7.02 5.72 8.94 7.32 6.00 zt-m 9.70 8.11 6.69 9.53 8.06 6.40 9.61 8.08 6.54 mean 9.33 7.72 6.25 8.68 7.25 5.59 9.00 7.48 5.92 nutrient v f pf v f pf v f pf n1 8.83 7.08 5.91 8.21 6.36 5.38 8.52 6.72 5.64 n2 9.23 7.76 6.15 8.49 7.40 5.63 8.86 7.58 5.89 n3 9.93 8.31 6.69 9.33 8.00 5.76 9.63 8.16 6.23 mean 9.33 7.72 6.25 8.68 7.25 5.59 9.00 7.48 5.92 source lsd (0.05) nutrient 0.217 residue 0.238 variety 0.145 stage 0.258 residue*var 1.234 n1 = 40:20:20 as n:p2o5: k2o, n2 = recommended n:p2o5: k2o = 80:40:40, n3 = n2 + 10 t ha-1 fym, fym = farmyard manure, zt = zero tillage with residue removal, zt-h = zero tillage with tall stubble height, zt-m = zero tillage with residue removal but with straw mulch, v= vegetative stage, f= flowering stage, pf= pod formation stage. table 4. total water used of lentils (cm) under different nutrient and residue management practices asha subrata mean residue/ tillage d (cm) p (cm) w (cm) d (cm) p (cm) w (cm) d (cm) p (cm) w (cm) zt 6.90 12.90 19.70 6.40 12.90 19.20 6.65 12.90 19.45 zt-h 5.90 12.90 18.80 6.00 12.90 18.90 5.95 12.90 18.85 zt-m 5.70 12.90 18.60 6.00 12.90 18.90 5.85 12.90 18.75 mean 6.17 12.90 19.03 6.13 12.90 19.00 6.15 12.90 19.02 nutrient d (cm) p (cm) w (cm) d (cm) p (cm) w (cm) d (cm) p (cm) w (cm) n1 6.58 12.90 19.40 6.77 12.90 19.60 6.68 12.90 19.50 n2 6.28 12.90 19.10 6.17 12.90 19.10 6.23 12.90 19.10 n3 5.65 12.90 18.60 5.46 12.90 18.30 5.56 12.90 18.45 mean 6.17 12.90 19.03 6.13 12.90 19.00 6.15 12.90 19.02 source lsd (0.05) nutrient 0.277 residue 0.338 residue*variety 3.086 n1 = 40:20:20 as n:p2o5: k2o, n2 = recommended n:p2o5: k2o = 80:40:40, n3 = n2 + 10 t ha-1 fym, fym = farmyard manure, zt = zero tillage with residue removal, zt-h = zero tillage with tall stubble 73 effect of balanced fertilization in puddled rice on the productivity of lentil height, zt-m = zero tillage with residue removal but with straw mulch, d= depletion, p= precipitation, w= water used. plant growth parameters leaf relative water content (rwc) is of the best growth/biochemical indices revealing the stress intensity (alizade, 2002). the rwc increased from vegetative to pod formation stages under all the treatments (fig. 2). the rwc ranged from 62-65% during vegetative to 72-78% during flowering to 75-87% at pod formation stage for residue and nutrient management practices and it was significantly (p < 0.05) higher in zt-h and zt-m throughout the growth period as compared to zt. at pod formation stage, zt-h and zt-m treatments significantly (p < 0.05) increased 12-15% higher rwc than zt. on the other hand, rwc in n3 and n2 were 2-7% higher than n1. results thus indicated that where there were more moisture (plots with applied mulch and residue retention), the plants were turgid and succulent producing higher rwc compared to residue removal with low amount of moisture (fig. 2). both varieties had no significant effect on rwc at different growth periods. 74 bandyopadhyay et al. fig. 2. relative water content under different nutrient and residue management practices zero tillage with straw mulching had maximum dry biomass compared to zt-h and zt treatments at flowering and pod formation stages (fig. 3). zt-h and zt-m produced 21 and 63% higher biomass as compared to zt, and zt-m produced 35% higher biomass than zth. on the other hand, n3 had 41% higher biomass than n2 and 57% higher than n1, respectively (fig. 3). asha (b-77) produced only 6% higher biomass than subrata (wbl-58). root:shoot ratio decreased with the advancement of crop growth (fig. 4) indicating less root proliferation in zero tillage condition. zt produced higher root-shoot compared to zt-h and zt-m may be due to increase of root system in cracks developed under moisture stress (bandyopadhyay, 2014). fig. 3. dry biomass under different nutrient and residue management practices 75 effect of balanced fertilization in puddled rice on the productivity of lentil fig. 4. root: shoot ratio under different nutrient and residue management practices fig. 5. soil drying out pattern under zero tillage (zt) with stubble height (zt-h) and with mulch (zt-m) soil properties soil drying pattern of zt-m was slower than zt-h and zt at surface (0-5 cm) and subsurface (5-20 cm) soil layers (fig. 5) throughout the growth period. during initiation of flowering (60 das) zt achieved 0.8 mpa tension as compared to 0.2 and 0.1 mpa for zt-h and zt-m, respectively. results thus showed that the drying out pattern during flowering to pod formation stage may be modified by keeping straw mulching (zt-m) or tall stubble height (zt-h). the intensity of stress faced by lentil, under zero tillage is depicted in fig. 6. at the beginning of the growing season (10 das), lentil in zero tillage showed the values of ks = 1, i.e., the soil water deficit was less than the readily available water of the root zone. during flowering stage, lentil with residue removal (zt) experienced more than 20% stress 76 bandyopadhyay et al. and it increased gradually. the diminution of ks values may be attributed to the increase in water depletion at the root zone through the removal of water by evapotranspiration that induced stress condition (bandyopadhyay and mallick, 2003). the ks values of the soil to 40 cm rooting depth reached below a value of 0.5 and 0.8 (fig. 6) at pod formation stage (100 d) with zt and zt-h, however, stress starts in zt-m after 105 d when the pod matured. a steep decrease with prolonged lower ks values of zt indicates a more stressed condition than zt-h (fig. 6). thus, zero tillage reduced the intensity of stress. zero tillage and nutrient management had an effect on soil microbial biomass carbon (smbc) and soil dehydrogenase activity (fig. 7). mulch treatment (zt-m) produced more smbc and dehydrogenase as compared to residue removal (zt) and low fertility (n1). asha (b-77) and subrata (wbl-58) had no significant effect on smbc and dehydrogenase activity. fig. 6. soil water stress coefficients under different residue management practices fig. 7. microbial biomass c and soil dehydrogenase activity under different nutrient and residue management practices yield and water use efficiency 77 effect of balanced fertilization in puddled rice on the productivity of lentil pooled data of yield for three years indicated that the yield was significantly affected by zero tillage and nutrient management as zt-m > zt-h > zt and n3 > n2 > n1 (table 5). zt-m (22.1 q ha-1) produced 19.0 and 14.5% more yield than zt (17.9 q ha-1) zt-h (18.9 q ha-1). n3 (20.9 q ha-1) produced 7 to 11% more than n2 and n1, respectively. there was no significant variation in yield between variety (19.2 and 20.1 q ha-1). tripathi and singh (1987), singh and verma (1996) in north india found the highest yield of 22.9 and 18.4 q ha-1 using different varieties. zt-m significantly produced 15 and 25% higher water use efficiency (wue) as compared to zt-h (21.7 kg ha-1mm-1) and zt (19.1 kg ha-1mm-1). nutrient management with n3 improved wue @14 to 21% as compared to n2 and n1. the achieved wue values of lentil in our study were within the range as described by singh et al. (2010). zero tillage with straw mulching modified soil temperature and kept minimal diurnal variation which tends to proliferate root and nutrient uptake that increased yield and wue. table 5. seed yield of lentil under different nutrient and residue management practices n1 n2 n3 overall variety/ treatment zt zt-h ztm mean zt zth ztm mean zt zth ztm mean zt zth ztm mean asha (b-77) 16.5 17.7 20.9 18.4 17.4 18.4 21.1 19.0 17.8 19.7 23.5 20.3 17.2 18.6 21.8 19.2 subrata (wbl58) 17.5 18.4 20.7 18.9 18.5 19.2 21.6 19.8 19.9 20.1 24.6 21.5 18.7 19.2 22.3 20.1 mean 17.0 18.1 20.8 18.6 17.9 18.8 21.4 19.4 18.9 19.9 24.1 20.9 17.9 18.9 22.1 19.6 source lsd (0.05) nutrient 1.20 residue 1.56 n1 = 40:20:20 as n:p2o5: k2o, n2 = recommended n:p2o5: k2o = 80:40:40, n3 = n2 + 10 t ha-1 fym, fym = farmyard manure, zt = zero tillage with residue removal, zt-h = zero tillage with tall stubble height, zt-m = zero tillage with residue removal but with straw mulch. table 6. water use efficiency as affected by different nutrient and residue management practices n1 n2 n3 overall variety/ treatment zt zth ztm mean zt zth ztm mean zt zth ztm mean zt zth ztm mea n asha (b-77) 16.1 19.6 23.2 19.6 18 20.6 24 20.9 19 23.6 30.2 24.3 17.7 21.3 25.8 21.6 subrata (wbl-58) 17.2 19.6 22.3 19.7 20 23 23.8 22.3 24.1 24 29.7 25.9 20.4 22.2 25.3 22.6 mean 16.7 19.6 22.8 19.7 19.0 21.8 23.9 21.6 21.6 23.8 30.0 25.1 19.1 21.7 25.5 22.1 source lsd (0.05) nutrient 3.807 residue 2.239 n1 = 40:20:20 as n:p2o5: k2o, n2 = recommended n:p2o5: k2o = 80:40:40, n3 = n2 + 10 t ha-1 fym, fym = farmyard manure, zt = zero tillage with residue removal, zt-h = zero tillage with tall stubble height, zt-m = zero tillage with residue removal but with straw mulch. conclusions 78 bandyopadhyay et al. zero tillage with straw mulch (zt-m) in both lentil varieties conserved 12-20% more water than residue removal (zt) and 7-10% more than standing residue (zt-h), respectively. depletion was more in residue removal (zt), followed by standing residue (zt-h) and mulch (zt-m) that could influence soil drying through increasing soil stress and resistance. zt-m and application of balanced fertilizer with fym (n3) produced higher biomass, rwc and improved soil microbial diversity. mulch maintained soil temperature and water movement for growth and rooting in zero tillage system that produced 19 and 14% more yield and 25 and 15% more wue than zt-h and zt, respectively. zero tillage reduced the intensity of stress. both lentil var. asha (b-77) and subrata (wbl-58) performed well under zero tillage system in this region. balanced fertilization in rice cultivation and zero tillage with straw mulching or keeping tall stubbles height may be an efficient use of existing natural resources for mitigating soil moisture stress and could sustain lentil productivity above national average. acknowledgements the financial support of the national agricultural science fund (nasf), indian council of agricultural research (icar), new delhi, for conducting the research is thankfully acknowledged. references acharya, c. l. and p. d. sharma. 1994. tillage and mulch effect on soil physical environment, root growth, nutrient uptake and yield of maize and wheat on an alfisol in north-west india. soil till. res. 32: 291-302. alizade., a. 2002. soil, water and plants relationship. 3rd ed. emam reza university press, mashhad, iran. p. 353. allen, r. g., l. s. pereira, d. raes and m. smith. 1998. crop evapotranspirationguidelines for computing crop water requirements, irrigation and drain, paper no. 56. fao, rome, italy. p. 300. bandyopadhyay, p. k. 2014. root distribution pattern of pulses in response to water availability. in: resource conservation technology in pulses. p. k. ghosh, m. s narendra kumar, venkatesh, k. k. hazra and n. nadarajan (eds.). scientific publishers, india. pp. 512520. bandyopadhyay, p. k. and s. mallick. 2003. actual evapotranspiration and crop coefficients of wheat (triticum aestivum) under varying moisture levels of humid tropical canal command area. agric. water manage. 59: 33-47. barrs, h. d. and p. e. weatherly. 1962. a re examination of relative turgidity for estimating water deficit in leaves. aust. j. biol. sci. 15: 413-428. fao, 2010. faostat statistical database of the united nations food and agriculture organization (fao), rome, italy. gangwar, k. s., k. k. singh, s. k. sharma and o. k. tomar. 2006. alternative tillage and crop residue management in wheat after rice in sandy loam soils of indo-gangatic plains. soil till. res. 88: 242-252. ghosh, p. k., a. das, r. saha, k. enboklang, a. k. tripathi, g. c. munda and s. v. ngachan. 2010. conservation agriculture towards achieving food security in north east india. curr. sci. 99: 915-921. 79 effect of balanced fertilization in puddled rice on the productivity of lentil gupta, s. and m. k. bhowmick. 2005. scope of growing lathyrus and lentil in relay cropping systems after rice in west bengal, india. lathyrus lathyrism newsletter. 4: 28-33. kar, g. and a. kumar. 2009. evaluation of post-rainy season crops with residual soil moisture and different tillage methods in rice fallow of eastern india. agric. water manage. 96: 931–938. kumar, s., r. g. singh, c. piggin, a. haddad, s. ahmed and raj kumar. 2011. no-till lentil: an option for profitable harvest in dry areas. grain legumes. 57: 39-42. lal, m., p. c. gupta and r.k. pandey. 1988. response of lentil to different irrigation schedules. lens newsleter. 15: 20-23. materne, m. and a. a. reddy. 2007. commercial cultivation and profitability of lentil. in: lentil: an ancient crop for modern times. yadav s. s., d. mcneil, p. c. stevenson (eds.). springer, dordrecht, the netherlands. pp. 173-186. pratibha, g., k. g. pillai, v. satyanarayan and m. m. hussain. 1996. tillage systems for production of black gram (vigna mungo) succeeding rice crops. legume res. 19: 23-28. sarker, b. c., m. hara and m. uemura. 2005. proline synthesis, physiological responses and biomass, yield of eggplants during and after repetitive soil moisture stress. sci. hort. 103: 387-402. singh, n. b. and k. k. verma. 1996. response of lentil genotypes to spacing in flood prone area. indian j. agron. 41(4): 657-658. singh, r., d. k. kundu and k. k. bandyopadhyay. 2010. enhancing agricultural productivity through enhanced water use efficiency. j. agric. phy. 10: 1-15. soil survey staff. 2003. keys to soil taxonomy. 9th edn. usda-nrcs. us government printing office, washington, dc. tripathi, n. c. and n. p. singh. 1987. response of lentil cultivars to spacing and seeding rate. indian j. agron. 32(1): 1-3. tuti, m. d., d. mahanta, b. l. mina, r. bhattacharya, j. k. bisht and j. c. bhatt. 2012. performance of lentil (lens culinaris) and toria (brassica campestris) intercropping with wheat (triticum aestivum) under rainfed conditions of north-west himala 80 bandyopadhyay et al. 1 bangladesh agron. j. 2016, 19(2): 139-143 productivity improvement ofpremium quality ricethrough fertilizer management in the haor areas m.a. aziz and m.a. kashem department of soil science, shylhet agricultural university, shylhet 3100, bangladesh corresponding author: aziz soil @ yahoo.com key words: productivity, premium quality rice, fertilizer management, haor areas abstract the experiment was conducted at the farmers’ fields of two villages namely bahadurpur and noagaonat sadar upazilla and daskin sunamganj, respectively under dekhar haor of sunamganj district during the period from november, 2015 to may 2016 to find out the effect of variety and fertilizer on the, yield and yield contributing characters of premium quality rice in haor area. two varieties (brri dhan50 and brri dhan63) and three fertilizer treatments (farmers’ practice, frg and soil test based fertilizers) were included in the experiment. the experiment was laid out in a factorial randomized complete block design (rcbd) with three dispersed replications. tillers hill-1 was significantly affected due to different varieties at 60, 75, 90 dat (days after trasplnting) and at harvest but significantly varied due to different fertilizers application at 30 and 60 dat interaction at 45 and 60 dat. the maximum grain and straw yield of 3.86 and 5.67 t ha–1, respectively was produced from the brri dhan63. though the grain yield was identical but lower yield in the stb and maximum in farmers’ practice due to higher fertilizer. practices. introduction rice grain is categorized into coarse, medium and fine with different colors based on physical properties. in bangladesh, a number of fine rice and premium quality rice are grown by the farmers. some of them have special characteristics for their aroma. such common varieties / cultivars are chinisagar, basmati, badshabhog, brri dhan34, br5, kalizira, tulsimla, brri dhan37, brri dhan38, brri dhan50, bina dhan12 and bina dhan15. fine rice is mainly used by the people in the preparation of palatable dishes and sold at a higher price in the market due to its special characters for aroma and acceptability. bangladesh has already exported fine rice in different countries with small quantity but bright prospect for export of this fine rice to earn foreign exchange. the grain yield of fine rice is lower than that of coarse and medium rice. the reason for low yield is mainly associated with lack of improved varieties and judicious fertilizer management especially of organic fertilizer and inorganic fertilizer. selection of a potential variety, planting in appropriate method and application of optimum amount of nutrient elements can play an important role to increase yield. however, fine rice is grown well under low levels of inputs. most of the fine rice varieties are grown as t. aman season due to their photosensitivity character. some premium quality rice like, brri dhan50, brri dhan63 are cultivated in bangladesh during boro season.. due to high organic matter in haor, the quality of premium quality rice rice may be superior from other region. after receding of water, plant should be planted earlier so that they can avoid flash flood. among the management practices, application of nitrogen fertilizer and variety are the important ones in this context the trial was conducted to find out suitable variety and optimum fertilizer for premium rice of haor areas. 140 aziz et al. materials and methods the experiment was conducted at the farmers’ fields of two villages namely bahadurpur and noagaon at sadar upazilla and daskin at sunamganjunder dekhar haor of sunamganj district during the period from november, 2015 to may 2016. two varietiesv1= brri dhan50 and v2= brri dhan63 and three fertilizer treatmentsf1= farmers’ practice (180-42-42 kg/ha of urea-tsp-mop), f2= ferilizer recommendatio guide ’12 based on fertilizers dose (300-112-127-75-11 kg/ha of urea-tsp-mopcas04-zns04) and f3= soil test based fertilizers (265-175-134-35-4 kg/ha of urea-tspmop-cas04-zns04) were included in the experiment.the initial soil properties of the experimental sites are presented in table 1. soil texture, ph, organic matter, available p and s, zn and exchangeable k, were determined following standard methods (black, 1965; jackson, 1962; walkley and black, 1935; olsen et al., 1954 and page et al., 1982). the experiment was laid out in a factorial randomized complete block design (rcbd) with three dispersed replications. seeds were sown in seedbed on 28 november 2015. seedlings were transplanted on 4-5 january 2016 at 25 cm × 15 cm spacing. urea was applied as top dressing in three equal splits at 15, 30 and 45 days after transplanting.. two hand weddings were done where first weeding at 25 days after transplanting followed by second weeding after first weeding at 45 days. standing water was maintained 2-3 cm in the field throughout the growing period. five hills were tagged for counting the tillers and measuring the plant height. harvesting was done on 21-22 april 2016. ten hills were collected from each plot to record the yield contributing characters. the grain and straw yields were recorded. the data were analyzed and mean separation was done by dmrt. table 1.chemical characteristics of the initial soil of the experimental site constituents characteristics soil ph 4.9 organic matter(%) 1.7 total nitrogen (%) 0.11 exchangeable k (milimol 100 g-1 soil) 0.15 available p (µg g-1 soil) 1.00 available s (µg g-1 soil) 27 available zn (µg g-1 soil) 0.3 results and discussion plant height of brri dhan50 was significantly higher than brri dhan63 at 15 dat (table 2). plant height was also varied significantly due to different fertilizer application at 45 dat and at harvest and their interaction at 15 dat. the maximum plant height was produced for application of stb fertilizer at 15 dat (23.30 cm), 45 dat (53.21 cm) and at harvest (88.50cm) while lower height from farmers dose. there was trend to increase height with advancement of date of transplanting upto 90 dat and then slightly decrease at harvest. the number of tillers hill-1 of brri dhan50 was significantly higher than brri dhan63 at 60 dat (15.91), 75 dat (16.84), 90 dat (16.65) and at harvest (15.57) (table 3). number of tillers hill-1 was significantly varied due to application of different fertilizer doses at 30 and 60 dat. the highest number of tillers hill-1(15.90) was produced due to soil test based fertilizers (table 3). number of tillers hill-1 was significantly varied due to variety and fertilizer interaction at 45 and 60 141 productivity improvement of premium quality rice through fertilizer management in the haor areas dat. number of effective tillers hill-1 and number of grains panicle-1 was not significant due to variety, different fertilizer doses and their interaction. number of sterile spikelets panicle-1 of brri dhan63 was significantly higher than brri dhan50 but not significantly varied due to different fertilizer doses and its interaction. tillers/hill increased with advancement of days and declined at harvest. panicle length was varied significantly due to variety where brridhan50 showed higher than brridhan 63. the 1000grains weight was not varied significantly due to variety and different fertilizer doses but significant variation was observed in interaction where brridhan 50 with soil test based fertilizer showed higher grain weight. grain and straw yield was not significantly influenced by varieties, fertilizer doses and in their interaction. though insignificant but higher grain yield was obtained from brridhan 50 with farmers fertilizer dose followed by soil test based fertilizer dose. it is interesting to note that stb fertilizer dose showed lower yield as well as frg with much higher dose than farmers practices failed to show higher yield. table 2. effect of variety and fertilizers on plant height of premium quality rice at different days after transplanting treatment plant height (cm) 15 dat 30 dat 45 dat 60 dat 75 dat 90 dat at harvest variety brridhan50 22.83 33.66 51.01 69.78 78.53 88.46 85.96 brridhan63 20.86 32.83 52.52 70.06 77.70 90.63 85.76 level of significance ** ns ns ns ns ns ns fertilizer level f1 21.10 33.50 50.03 69.90 76.95 86.25 81.20 f2 21.15 32.55 52.05 68.95 78.60 90.60 87.90 f3 23.30 33.70 53.21 70.93 78.80 91.80 88.50 level of significance * ns * ns ns ns ** variety x fertilizer v1f1 23.40 35.30 49.90 68.10 75.40 85.10 82.40 v1f2 22.40 32.30 52.20 70.40 80.00 88.00 88.30 v1f3 22.70 33.40 50.93 70.86 80.20 92.30 87.20 v2f1 18.80 31.70 50.16 71.70 78.50 87.40 80.00 v2f2 19.90 32.80 51.90 67.50 77.20 93.20 87.50 v2f3 23.90 34.00 55.50 71.00 77.40 91.30 89.80 level of significance ** ns ns ns ns ns ns ** = significant at 1 % level of provability; * = significant at 5 % level of provability, ns= non-significant v1 = brri dhan50 v2 = brri dhan63 f1= farmers’ practice (180-42-42 kgha -1 of urea-tsp-mop) f2= fertilizer recommendation guide (300-112-127-75-11 kgha -1 of urea-tsp-mop-cas04zns04), f3= soil test based (265-175-134-35-4 kgha -1 of urea-tsp-mop-cas04-zns04). table 3. effect of variety and fertilizers on the tiller production of modern boro fine rice at different days after transplanting treatment tillers hill-1(no.) 15 dat 30 dat 45 dat 60 dat 75 dat 90 dat at harvest 142 aziz et al. variety brridhan50 3.03 6.10 12.13 15.91 16.84 16.65 15.57 brridhan63 2.76 5.66 11.66 13.63 15.41 15.17 14.48 level of significance ns ns ns ** * ** * fertilizer f1 2.65 5.25 11.20 13.36 15.36 15.45 14.40 f2 2.95 6.65 12.35 15.05 16.50 16.20 14.95 f3 3.10 5.75 12.15 15.90 16.51 16.10 15.75 level of significance ns * ns ** ns ns ns variety x fertilizer v1f1 2.40 5.10 11.40 13.80 16.10 16.40 15.00 v1f2 3.40 7.20 13.80 17.33 17.90 17.50 15.83 v1f3 3.30 6.00 11.20 16.60 16.53 16.06 15.90 v2f1 2.90 5.40 11.00 12.93 14.63 14.50 13.80 v2f2 2.50 6.10 10.90 12.76 15.10 14.90 14.06 v2f3 2.90 5.50 13.10 15.20 16.50 16.13 15.60 level of significance ns ns ** ** ns ns ns ** = significant at 1 % level of provability; * = significant at 5 % level of provability, ns= non-significant v1 = brri dhan50 v2 = brri dhan63 f1= farmers’ practice (180-42-42 kgha -1 of urea-tsp-mop) f2= fertilizer recommendation guide (300-112-127-75-11 kgha -1 of urea-tsp-mop-cas04zns04), f3= soil test based (265-175-134-35-4 kgha -1 of urea-tsp-mop-cas04-zns04). table 4. effect of variety and fertilizers on the yield and yield contributing characters of modern boro fine rice treatment effective tillers hill1 (no.) grains panicle-1 (no.) sterile spikelets panicle-1 (no.) panicle length (cm) 1000 grain weight (g) grain yield (tha-1) straw yield (t ha-1) variety brridhan50 14.65 108.70 10.16 21.34 19.87 3.25 5.58 brridhan63 13.84 110.74 11.96 19.76 19.71 3.86 5.67 level of significance ns ns * ** ns ns ns fertilizer f1 13.71 105.61 11.10 20.75 19.28 3.64 5.43 f2 14.21 114.55 11.25 20.60 20.25 3.59 5.54 f3 14.81 109.00 10.85 20.31 19.85 3.44 5.91 level of significance ns ns ns ns ns ns ns variety x fertilizer v1f1 14.20 104.10 9.30 21.03 17.73 3.15 4.95 v1f2 14.96 114.60 10.70 21.80 20.60 3.18 5.74 v1f3 14.80 107.40 10.50 21.20 21.30 3.42 6.06 v2f1 13.23 107.12 12.90 20.46 20.83 4.14 5.91 v2f2 13.46 114.50 11.80 19.40 19.90 4.00 5.34 v2f3 14.83 110.60 11.20 19.43 18.40 3.46 5.76 level of significance ns ns ns ns * ns ns ** = significant at 1 % level of provability; * = significant at 5 % level of provability, ns= non-significant v1 = brri dhan50 v2 = brri dhan63 f1= farmers’ practice (180-42-42 kg ha -1 of urea-tsp-mop) f2= fertilizer recommendation guide (300-112-127-75-11 kg ha -1 of urea-tsp-mop-cas04zns04), f3= soil test based (265-175-134-35-4 kg ha -1 of urea-tsp-mop-cas04-zns04). conclusion the result of the experiment revealed that the higher grain and straw yield of 3.86 and 5.67 t ha–1, respectively was produced from the brri dhan63. soil test based fertilizer dose failed to show higher yield than farmer practice. besides, frg with high 143 productivity improvement of premium quality rice through fertilizer management in the haor areas fertilizer dose did not increase yield in both the varieties. though slightly higher grain yield was obtained from brridhan 63 with farmers practice with the use of affordable fertilizer dose and as such farmers of haor areas are very much concerned about use of fertilizer dose (180-42-42 kg ha-1 of urea-tsp-mop ). acknowledgement we are thankful acknowledge for the financial support rendered by krisihi gobesona foundation under the project of farm productivity improvement in the haor areas through integrated farming system approach. references black, c.a. 1965. methods of soil analysis. part i and ii. amer. soc. agron. inc. pub., madison. usa. jackson, m.l. 1962. soil chemical analysis. constable and co. ltd. london. olsen s.r., c.v. cole, f.s. watanable and l.a. dean. 1954. estimation of available phosphorus in soils by extraction with sodium carbonate u.s. dept. agr. (circ.) pp.929. page, a.l., r.h. miller and d.r. keeney. 1982. methods of soil analysis part 2. 2nd ed. am. soc. agron. increased. madison. wisconsin, usa. pradhan, s.b. 1992. status of fertilizer use in developing countries of asia and the pasific region. proc. of reg. fadinap seminar. chiang mai. thailand. pp37-47. walkley, a. and a.i. black. 1935. an examination of the degtijaref method for determining soil organic matter and a proposed modification of the chromic acid titration method. soil sci., 37: 29-38. m.a. aziz and m.a. kashem department of soil science, shylhet agricultural university, shylhet 3100, bangladesh corresponding author: aziz soil @ yahoo.com key words: productivity, premium quality rice, fertilizer management, haor areas abstract the experiment was conducted at the farmers’ fields of two villages namely bahadurpur and noagaonat sadar upazilla and daskin sunamganj, respectively under dekhar haor of sunamganj district during the period from november, 2015 to may 2016 to find out... introduction materials and methods results and discussion the result of the experiment revealed that the higher grain and straw yield of 3.86 and 5.67 t ha–1, respectively was produced from the brri dhan63. soil test based fertilizer dose failed to show higher yield than farmer practice. besides, frg with hi... we are thankful acknowledge for the financial support rendered by krisihi gobesona foundation under the project of farm productivity improvement in the haor areas through integrated farming system approach. bangladesh agron. j. 2019, 22(2): 1-10 on-farm evaluation of improved pattern through inclusion of mustard in fallow period preceding t. aus-t. aman rice cropping in sylhet region *m.i. nazrul1 1pso, bangladesh agricultural research institute (bari), gazipur-1701. *corresponding e-mail: mi_nazrul@yahoo.com (received: 13 december 2019, accepted: 23 december 2019) keywords: rice based cropping pattern, land use efficiency, production efficiency, sustainableyield index, fallow land utilization abstract the study was conducted at the farmer’s field in sylhet under aez 20 during three consecutive years 2016-17, 2017-18 and 2018-19 to determine the productivity and profitability of cropping patterns viz. ip: improved pattern (mustard-t. aus-t. aman rice) by introducing high yielding varieties and improved management practices and fp: farmer’s pattern (fallow-t. aus-t. aman rice). the experiment was laid out in randomized complete block design with six dispersed replications. results showed that the improved pattern with management practices provided 6.88 and 22.84 % higher grain yield of t. aus and t. aman rice, respectively; also contributed higher mean rice equivalent yield (9.44 t ha-1) compared to farmer’s pattern.sustainable yield index (0.36), production efficiency (39.75 kg ha-1day-1), and land use efficiency (75.98 %) were maximum in mustard-t. aust. aman rice cropping system on an average. similarly, the highest mean gross margin (tk.1,12,425 ha-1) with benefit cost ratio (2.13) was obtained from improved pattern. three years results revealed that 24% extra cost provides an ample scope of considerable improvement of the productivity with the inclusion of mustard before t. aus rice in improved pattern. introduction in sylhet region, mainly fallow t. aus t. aman rice cropping pattern is widely followed by farmers under rainfed condition. transplantation of aus rice is being dependent on rainfall, which sown during early monsoon (early may). this delayed transplantation of t. aus rice that causes late cultivation and harvesting of t. aman rice, which hampered timely cultivation of rabi crops. the soils under these cropping pattern areas are generally heavy silty clay loams to clays and the top soil quickly becomes dry and hard after the harvest of t. aman rice. in eastern surma kushiara floodplain of sylhet region, a vast area remains fallow for a long time after the harvest of t. aman rice due to moisture stress up to next season for cultivation of t. aus rice following the existing cropping pattern (fallow-t. aus-t. aman rice). however, the yields of rice are very low compared to other regions of the country. generally, rainfall starts in february and prevails up to november in each year that offers an excellent opportunity for the production of short duration pulse and oilseed crops before t. aus rice. shaheb etal.(2012) reported that mustard varieties can be grown well in fallow land of sylhet where var. bari sarisha-14 and bari sarisha-17 could be more suitable and produced higher seed yield. to enhance the crop production through utilization of fallow land in sylhet region, the potato-rice and chickpearice based cropping patterns have been developed (nazrul et al., 2013; nazrul and shaheb, 2012; shaheb et al., 2011). 8 m. i. nazrul a number of reports on different cropping pattern are available in bangladesh that an additional crop could be introduced without much changes or replacing the existing ones for considerable increases of productivity as well as profitability of the farmers (azad et al. 1992; khan et al., 2005 and nazrul et al., 2013, kamrozzaman et al., 2015). but, little effort has been made for on-farm evaluation of the improved technologies of mustard-t. aus-t. aman rice cropping pattern in sylhet area. the present study was therefore, initiated to determine productivity and economic feasibility of an improved package of technologies over the farmer’s existing practices. materials and methods the study was carried out during three consecutive years 2016-17, 2017-18 and 2018-19 at farmer’s field, sylhet (24o54'n latitudes and 91o58' e longitude) located in agro ecological zone (aez)-20; under eastern surma kushiyara floodplain. this trial was conducted to derive the economic consequences of two cropping patterns viz. ip: improved pattern (mustard-t. aus rice-t. aman rice) and fp: farmer’s pattern (fallow-t. aus rice-t. aman rice) through incorporation of high yielding varieties with improved management practices. annual monthly total rainfalls, along with maximum and minimum average temperatures during the study period are presented in figure 1. the highest amount of average monthly rainfall occurred in june followed by july and may, whereas lowest amount of rainfall occurred in january followed by november and december. rainfall increases gradually from the month of january to june and then decreases. the crops received 4295, 5045 and 3575 mm total rainfall during crop season of 2016-17, 2017-18 and 2018-19, respectively. the monthly maximum air temperature of 35.80, 37.00 and 38.30oc and minimum of 10.30, 10.30 and 8.00oc during the crop season of 2016-17, 2017-18 and 2018-19, respectively. the soil was clay loam with low organic matter content (1.63%) and soil ph was ranged 4.1-5.63 acidic in nature. the initial status of n (0.07%), p (7.59 µg/soil), k (0.18 meq/100g soil), s (10.80 µg/soil), b (0.34 µg/soil) and zn (1.27 µg/soil) was very low, low, low, low, medium and medium, respectively. the trial was laid out in randomized complete block design with six dispersed replications. two plots of 500 m2 were selected for each replication. one plot was under the improved pattern and the other farmer’s pattern. in the improved pattern, mustard var. bari sarisha-14 was introduced against fallow period. t. aus rice var. brri dhan65 and t. aman rice var. brri dhan57 was introduced instead of br-26 and brri dhan33, respectively. the agronomic parameters and cultural operation for crop production under improved and farmer’s practices are presented in table 1. all field operation and management practices of both farmer’s and improved pattern were closely monitored and the data were recorded for agro-economic performance. the differences between mean was compared by t-test. agronomic performance viz. land use efficiency, production efficiency, rice equivalent yield and sustainable yield index of cropping patterns were calculated. land use efficiency is worked out by taking total duration of individual crop in a sequence divided by 365 days (tomer and tiwari, 1990). it is calculated by following formula: land use efficiency = d1 + d2 + d3 x 100 365 where d1, d2and d3the duration of first, secondand third crops of the pattern. production efficiency: production efficiency values in terms of kg.ha-1day-1were calculated by total production in a cropping sequence divided by total duration of crops in that sequence (tomer and tiwari. 1990). production efficiency = y1 + y2 + y3 (kg ha-1day-1) d1 + d2 + d3 on-farm evaluation of improved pattern through inclusion of mustard 9 where, y1: yield of first crop; and d1: duration of firstcrop of the pattern; y2: yield of secondcrop and d2: duration of second crop of the pattern; y3: yield of third crop and d3: duration of third crop of the pattern. sustainable yield index (syi):the yield data from two different cropping systems was processed and interpreted in terms of syi. the syi of individual treatment in each year of experimentation was calculated following the equation suggested by singh et al. (1990). sustainable yield index = (ytσ) ym where, yt is mean yield of respective treatment, σ is the standard deviation (sd) and ym is the maximum yield obtained under a set of management practices in any of the treatment and any of year in a given experiment.it indicates that sustainability in production over a period of time even though crop has high yields may or may not give sustainable yield index. sustainability depends upon variation in the yield during crop period; if during the initial period yield is very low and hereafterit reached very high, as here variation is more from starting period to last, there is more yield but less sustainability and if crop yield variation is less from the beginning to the end there may be higher or lower yield but syi would be higher. rice equivalent yield: for comparison between crop sequences, the yield of all crops was converted into rice equivalent yield (rey) on the basis of prevailing market price of individual crop (verma and modgal, 1983). rice equivalent yield (t ha-1) = yield of individual crop x market price of that crop market price of rice the economic indices like gross and net returns and benefit cost ratio were also calculated on the basis of prevailing market price of the produces. for economic evaluation of two different cropping sequences averaged data of two crop cycles were used. the gross cost of cultivation of different crops was calculated on the basis of different operations performed and materials used for raising the crops. benefit cost ratio (bcr) was also calculated by the following formula: benefit cost ratio (bcr) = gross return (tk. ha-1) total (variable) cost of cultivation(tk. ha-1) 8 m. i. nazrul fig.1. average of three years monthly total rainfall (mm), maximum and minimum air temperatures during study period (source: metrological department, sylhet). results and discussion yield of rice and mustard: in rice, the average yield of t. aus and t. aman was varied from 3.20 4.43 t ha-1. in mustard, the variety bari sarisha-14 was produced 1.19 t ha-1 of seed yield in cp2 whereas lands remain fallow in cp1 at that period. the variety of t. aus and t. aman rice was given higher grain yields under the pattern cp2 it might be due to use of improved rice variety. the highest average yield of t. aus (3.43 tha-1) and t. aman (4.40 tha-1) rice was provided by cp2(table 1). t. aman rice equivalent yield: the total productivity of the cropping sequence was ascertained by the rice equivalent yield (rey) it was calculated from the yields of component crops. rey was varied under different cropping sequence. in average of two years revealed that the highest rey (9.37 t ha-1) was recorded from cp2 as compared to cp1 (6.46 t ha-1). inclusion of mustard and modern variety of t. aus and t. aman rice in cp2 increased rey 45.00% as compared to cp1. 0 5 10 15 20 25 30 35 40 0 500 1000 1500 2000 2500 3000 jan. feb. mar. apr. may jun. jul. aug. sep. oct. nov. dec. total rainfall (mm) maximum tem. (0c) minimum tem. (0c) ra in fa ll (m m ) te m pe ra tu re (o c ) on-farm evaluation of improved pattern through inclusion of mustard 9 table 1. agronomic practices of improved (mustard t. aus-t. aman rice) and farmer’s existing (fallow-t. aus-t. aman rice) cropping patterns during 2016-19 parameters cropping pattern index farmer’s pattern (fp) improved pattern (ip) 2016-17 2017-18 2018-19 2016-17 2017-18 2018-19 variety c1 fallow fallow fallow bari sarisha-14 bari sarisha-14 bari sarisha-14 c2 br-26 br-26 br-26 brri dhan65 brri dhan65 brri dhan65 c3 brri dhan33 brri dhan33 brri dhan33 brri dhan57 brri dhan57 brri dhan57 date of sowing/ transplant c1 fallow fallow fallow 20-25 nov 20-25 nov 20-25 nov c2 10-15 may 10-15 may 10-15 may 10-15 may 10-15 may 10-15 may c3 12-15 aug 12-15 aug 12-15 aug 12-15 aug 12-15 aug 12-15 aug seed rate (kgha-1) c1 fallow fallow fallow 6-7 6-7 6-7 c2 35-40 35-40 35-40 25-30 25-30 25-30 c3 30-35 30-35 30-35 25-30 25-30 25-30 planting method c1 fallow fallow fallow broadcast broadcast broadcast c2 line line line line line line c3 line line line line line line spacing (cm) (rowhill) c1 fallow fallow fallow c2 2010 2010 2010 2515 2515 2515 c3 2015 2015 2015 2515 2515 2515 fertilizer dose (kgha1) (npkszn) c1 fallow fallow fallow 92-27-40-12-1.0 23-20-17-15-1.0 23-20-17-15-1.0 c2 83-20-40-5-1 83-20-40-5-1 83-20-40-5-1 75-15-30-6-0.6 75-15-30-6-0.6 75-15-30-6-0.6 c3 92-24-60-8-0.5 92-24-60-8-0.5 92-24-60-8-0.5 90-10-35-8-1.0 90-10-35-8-1.0 90-10-35-8-1.0 fertilizer application method c1 fallow fallow fallow half n and all other fertilizer nutrients applied as basal; remaining n top dressed at flowering half n and all other fertilizer nutrients applied as basal; remaining n top dressed at flowering half n and all other fertilizer nutrients applied as basal; remaining n top dressed at flowering c2 all pks used as basal during final land preparation. nused in 2 equal splits at 15-20 dat and another one in 35-40 dat. all pks used as basal during final land preparation. nused in 2 equal splits at 15-20 dat and another one in 35-40 dat. all pks used as basal during final land preparation. n2used in 2 equal splits at 15-20 dat and another one in 35-40 dat. half of nitrogen and all other fertilizers applied as basal during final land preparation. remaining nitrogen was top dressed at 40-45 das under moist soil condition half of nitrogen and all other fertilizers applied as basal during final land preparation. remaining nitrogen was top dressed at 40-45 das under moist soil condition half of nitrogen and all other fertilizers applied as basal during final land preparation. remaining nitrogen was top dressed at 40-45 das under moist soil condition c3 all pks used as basal all pks used as basal all pks used as basal all pkszn used as basal all pkszn used as basal all pkszn used as basal 8 m. i. nazrul parameters cropping pattern index farmer’s pattern (fp) improved pattern (ip) 2016-17 2017-18 2018-19 2016-17 2017-18 2018-19 during final land preparation. nused in 2 equal splits at 15-20 dat and another one in 35-40 dat. during final land preparation. nused in 2 equal splits at 15-20 dat and another one in 35-40 dat. during final land preparation. nused in 2 equal splits at 15-20 dat and another one in 35-40 dat. and n used in 3 equal splits, the first one after 15dat, second one at 35-40 dat and third one at 5-7 days beforepanicle initiation and nused in 3 equal splits, the first one after 15 dat, second one at 35-40 dat and third one at 5-7 days before panicle initiation and n used in 3 equal splits, the first one after 15dat, second one at 35-40 dat and third one at 5-7 days before panicle initiation weeding (no.) c1 fallow fallow fallow 0 0 0 c2 2 2 2 2 2 2 c3 1 1 1 2 2 2 irrigation/r ainfed c1 fallow fallow fallow rainfed rainfed rainfed c2 rainfed rainfed rainfed rainfed rainfed rainfed c3 rainfed rainfed rainfed rainfed rainfed rainfed insect-pest control c1 fallow fallow fallow ipm ipm ipm c2 chemical chemical chemical ipm ipm ipm c3 chemical chemical chemical ipm ipm ipm harvest time (date) c1 fallow fallow fallow 20-28 feb. 20-28 feb. 20-28 feb. c2 10-15 aug 10-15 aug 10-15 aug 28-30 july 28-30 july 28-30 july c3 10-16 dec 10-16 dec 10-15 dec 15-20 nov 15-20 nov 15-20 nov field duration (days) c1 fallow fallow fallow 75-80 75-80 75-80 c2 105-110 105-110 105-110 95-100 95-100 95-100 c3 112-115 112-115 105-115 100-105 100-105 100-105 total duration (days) 217-225 217-225 210-225 270-285 270-285 270-285 c1: fallow/mustard; c2: t. aus; c3: t. aman rice; ipm: integrated pest management grain/seed yield of the cropping patterns improved pattern took 270-285 days against 217-225 days due to inclusion of mustard the pattern. this indicates that mustard could easily be grown or fitted before t. aus rice. the grain yield of rice was significantly higher in the improved pattern as compared to farmers existing pattern during individual years and mean data (table 2). variation in the yield of rice as evident in the improved pattern might be due to change of variety with improved production technologies. similar results were also obtained by nazrul et al. (2013) and khan et al. (2005) in case of rice based cropping sequences. in all the years, farmers’ pattern gave lower grain yield of rice due to imbalance use of fertilizers and traditional management practices. on the contrary, the yield of t. aus and t. aman rice was higher in improved pattern due to insertion of high yielding modern rice varieties. during experimentations in year of 2017-18, the rice bug was found in t. aman rice field at panicle formation to flowering. but it was successfully controlled by applying chlorpyrifos insecticide (dursban 20 ec @ 20 ml in 10 liters of water for 5 decimal areas). the rice variety, brri dhan65 and brri dhan57 in improved pattern performed better than br-26 and brri dhan33 in farmers’ practices due to higher yield potential of the variety. by-product yield of the cropping patterns the improved cropping pattern produced higher amount of total by-product yield (9.06 tha-1) than the by-product yield of the crops (8.74 t ha-1) of the farmers’ pattern (table 2). the by-product yield of improved pattern was higher due to introduction and change of variety with improved technologies for the component crops. in all the years, mustard contributed valuable by-product. on the contrary, on-farm evaluation of improved pattern through inclusion of mustard 9 farmers are not able to sale by-product (rice straw) in the local market; whereas, the by-product of mustard has been used as fuel by the farmers. table 2. productivity of improved (mustard-t. aus-t. aman) and farmer’s existing (fallow-t. aus-t. aman) cropping patterns during 2016-19 years cropping patterns seed/grain yield (t ha-1) by product yield (t ha-1) fallow/mustard t. aus t. aman fallow/mustard t. aus t. aman 2016-17 fp 3.20 3.64 4.25 4.68 ip 1.19 3.42 4.43 3.19 4.32 4.75 2017-18 fp 3.17 3.60 4.20 4.56 ip 0.96 3.43 4.36 3.00 4.35 4.72 2018-19 fp 3.22 3.54 4.14 4.35 ip 1.20 3.40 4.44 3.21 4.35 4.70 mean fp 3.20 3.59 4.21 4.53 ip 1.12 3.42 4.41 3.13 4.34 4.72 rice equivalent yield the component crops of mustard-t. aus-t. aman rice cropping pattern under improved practices (ip) gave higher t. aman rice equivalent yields against grain yield as well as by-product in all the years. the mean rice equivalent yield under improved cropping pattern also produced higher rice equivalent yield over farmers’ traditional cropping pattern (table 3). on an average, the t. aman rice equivalent yield in improved pattern increased 47% over the crops under farmers’ practices. inclusion of high yielding new crop varieties with improved management practices increased the higher t. aman rice equivalent yield. it was also due to higher price of components crops in the improved pattern. lower rice equivalent yield was obtained in the farmers’ pattern probably due to variety and traditional management practices. production efficiency maximum production efficiency was obtained from improved pattern during individual years and also means data (table 3). the higher production efficiency of improved cropping pattern might be due to inclusion of a new or modern varieties and management practices. in conversely, the lowest production efficiency was observed in farmers’ pattern where crop remained in the field for shorter time and yields were also lower, leading to lower production per day. mean production efficiency (39.75 kg ha-1day-1) was higher in improved pattern and lower (30.18 kg ha-1day-1) in farmers’ pattern. similar trend were noted by nazrul et al. (2013) and khan et al. (2005) in case of improved cropping sequences. land use efficiency land use efficiency is the effective use of land in a cropping year, which mostly depends on crop duration. the average land-use efficiency indicated that improved pattern used the land for 75.98% period of the year, whereas farmer’s pattern used the land for 60.55% period of the year (table 3). the land use efficiency was higher in improved pattern due to cultivation of mustard as additional crop in fallow period. sustainable yield index the sustainable yield index (syi) of farmer’s and improved cropping pattern is presented in table 3. the values of sustainable yield index as a measure of sustainability of the system which was high in the improved cropping system (0.34-0.37) over farmer’s practices (0.18). the results showed that between two different cropping systems mustard-t. aus-t. aman rice recorded the highest mean syi of 0.36 followed by fallow-t. aus-t. aman rice (0.18). so, cropping system including mustard in fallow period and modern varieties of t. aus and t. aman rice recorded higher syi compared to fallow-rice based crop sequences. the results are in agreement with the findings of nazrul et al. (2017); nazrul et 8 m. i. nazrul al. (2013) and ram et al. (2012). this indicated that improved pattern is therefore, more stable than farmer’s pattern. mustard is providing special advantage regarding utilization of mustard straw as fuel instead of cow dung. table 3. rice equivalent yield, production efficiency, land use efficiency and sustainable yield index of improved and farmers patterns at farmer’s field during 2016-19 years cropping patterns rice (t. aman) equivalent yield (tha-1) production efficiency (kg ha-1day-1) land use efficiency (%) sustainable yield index (syi) 2016-17 fp 6.48 30.40 59.45 0.18 ip 9.59 40.18 73.97 0.37 2017-18 fp 6.42 30.09 60.55 0.18 ip 9.12 38.89 75.90 0.34 2018-19 fp 6.40 30.04 61.64 0.18 ip 9.59 40.18 78.08 0.37 mean fp 6.43 30.18 60.55 0.18 ip 9.43 39.75 75.98 0.36 economic between two crop sequences, the improved cropping pattern showed its superiority over farmers’ existing pattern during three consecutive years of cropping season. on an average, gross return of the improved pattern was tk. 212175 ha-1 which was more than 47% higher than farmers’ pattern of tk. 144675 ha-1 (table 4). the production cost of the improved pattern (tk. 99750 ha-1) was higher than farmers’ pattern (tk. 80761 ha-1) due to introduction of mustard in fallow period, cost of fertilizer and other inputs. the gross margin was substantially higher in the improved pattern (tk. 112425 ha-1) than farmers’ pattern (tk. 63914 ha-1). inclusion of mustard and improved varieties of rice in these cropping systems, increasing the system productivity fetched higher market price; thereby, increasing the gross margin. the 76 % additional gross margin was achieved by adding 24 % additional cost in the improved pattern. returns per taka invested were highest for mustard-t. aus-t. aman rice (2.13) over the farmers’ pattern (1.79). table 4. cost benefit analysis of improved and farmer’s existing cropping pattern at farmer’s field (average of three years). years cropping patterns gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr 2016-17 fp 145800 80761 65039 1.81 ip 215775 99750 116025 2.16 2017-18 fp 144450 80761 63689 1.79 ip 205200 99750 105450 2.06 2018-19 fp 144000 80761 63239 1.78 ip 215775 99750 116025 2.16 mean fp 144675 80761 63914 1.79 ip 212175 99750 112425 2.13 notefp: farmer’s pattern, ip: improved patter; the costs (tk. kg-1): rice seed (32.00), mustard seed (90.00), and, urea (20.00), tsp (22.00) and mop (15.00); among field operations, the cost of plowing was taken as tk. 10 decimal-1, labour cost of tk. 350m-1 day-1. gross returns included income from sale of main and by-products (tk. ka-1) of all crops; t. aus rice (20.00), t. aman rice (22.50), mustard (40.00), rice straw (0.50), mustard stover (1.00). on-farm evaluation of improved pattern through inclusion of mustard 9 conclusion three years study revealed that mustard-t. aus-t. aman rice cropping system is more productive, sustainable and remunerative for medium high land under eastern surma kushiyara floodplain (aez 20). so, farmers of commanding area could follow mustard (var. bari sarisha-14)-t. aus (var. brri dhan65)-t. aman rice (var. brri dhan57) cropping pattern for higher productivity and profitability as well as mustard straw can be utilized as fuel instead of cow dung. acknowledgements authors are gratefully acknowledged bangladesh agricultural research institute, gazipur and metrological department, sylhet for providing financial help and logistic support and weather data, respectively. thanks to others who contributed in editing and compiling the manuscript. references azad, a.k., f.a.h. talukdar, m.a. wahhab and m.a. khan. 1992. progress and prospect of jute based cropping systems research in bangladesh. proc. expert cons. jute and kenaf improvement: pp.244-267. kamrozzaman, m.m., m.a.h. khan, s. ahmed and a.f.m.r. quddus. 2015. on-farm evaluation of production potential and economics of wheat-jute-t. aman rice-based cropping system. j. bangladesh agril. univ. 13(1): 93–100. khan, m.a.h., m.a. quayyum, m.i. nazrul, n. sultana and m.r.a. mollah. 2005. on-farm evaluation of production potential and economics of mustard-rice based improved cropping system. j. socio. res. dev. 2(1): 37-42. nazrul, m.i. and m.r. shaheb. 2012. potato-t. aus-t. aman: an improve and sustainable cropping pattern for fallow land utilization of sylhet. published by on-farm research division, bangladesh agricultural research institute (bari), sylhet-3100. p.24. nazrul, m.i., m.k. hasan and m.r.i. mondal. 2017. production potential and economics of mung bean in rice based cropping pattern in sylhet region under aez 20. bangladesh j. agril. res. 42(3):413424. nazrul, m.i., m.r. shaheb, m.a.h. khan and a.s.m.m.r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh j. agril. res. 16(2): 41-50. ram, a.j., r.a. dungrani, m.k. arvadia and k.l. sahrawat. 2012. diversification of rice (oryza sativa l.) based cropping systems for higher productivity, resource-use efficiency and economic returns in south gujarat of india. archives agron. soil sci. 58(6): 561-572. shaheb, m.r, m.i. nazrul, a.k. chowdhury, m.m.r sarker, a.s.m. khan and j.u. sarker. 2011. chick pea-t. aust. aman: a prosperous and improved cropping pattern for sylhet region. published by onfarm research division, bangladesh agricultural research institute (bari), sylhet-3100. p.13. shaheb, m.r., m.i. nazrul and m. ali.2012. performance of mustard varieties for fallow land utilization in sylhet region. bangladesh agron. j. 15(2): 47-52. singh, r.p., s.k. das, u.m.b. rao andm.n. reddy. 1990. towards sustainable dryland agriculture practices, bulletin, crida, hyderabad, india. tomer, s.s and a.s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35(1, 2): 30-35. verma, s.p and s.c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2): 89-92. bangladesh agron. j. 2016, 19(2): 105-114 physiological changes of wheat varieties under water deficit condition t. tasmina1, a. r. khan2*, a. karim3, n. akter2 and r. islam1 1ms student, 2, 3department of agronomy bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 *corresponding author: arifkhanbsmrau@gmail.com key words: physiology, derivations, wheat, water shortage abstract the experiment was carried out at the research field of the department of agronomy of bangabandhu sheikh mujibur rahman agricultural university, gazipur during november 2014 to march 2015 to assess and evaluate the physiological derivations of wheat varieties under water deficit condition. the experiment was laid out in a split plot design comprising two water regimes (irrigated or control and water stress) in main plot and three wheat varieties (bari gom 25, bari gom 26 and sourav) in sub-plot with four replications. surface irrigation was applied into the irrigated plots in total growing season but it was applied in water stress plots up to 21 days after sowing after that irrigation was stopped in water stress plots. it was revealed that studied parameters were significantly influenced by water regimes, variety and their interaction. the xylem exudation rate, light interception, spad value, leaf water potential, relative water content, water retention capacity was higher in irrigated condition where canopy temperature, water uptake capacity, water saturation deficit higher in water stress condition.the wheat var. bari gom 26 showed the highest par, spad value, leaf water potential, relative water content, water retention capacity where bari gom 25 exhibit lowest under water deficit condition. on the other hand, bari gom 25 showd the highest canopy temperature, water uptake capacity and water saturation deficit in water deficit condition. therefore, considering the physiological performance and other characters bari gom 26 could be considered preferably for water shortage condition followed by sourav where bari gom 25 was susceptible one. introduction wheat (triticum aestivum) is world’s most widely cultivated food crop and the second important cereal crop in bangladesh. it provides 21% of the food calories for more than 4.5 billion peoples in 94 countries of the world (braun et al., 2010). wheat is grown in rabi season from october to march which is characterized by very low or no rainfall in bangladesh. most of the farmers grow wheat with irrigation but due to scarcity of water or very low or no rainfall affects the plant growth and productivity (khaliq et al., 1999). water is necessary for plant growth of different metabolic activities but drought causes disorders at morphological, physiological, biochemical and molecular levels (saeedipour, 2012). a physiological approach would be the most attractive way to develop new varieties (araus et al., 2008). morphological studies have been conducted in bangladesh to identify drought tolerance wheat varieties for higher wheat production and a major challenge for wheat breeders for several decades. in order to identify suitable varieties for drought prone areas, the mechanisms on water stress tolerance has to be better understood. however, more intensive study is required to understand the mechanisms of drought tolerance of wheat. as such, the present research was conducted to study the physiological changes of wheat varieties under water shortage condition. 106 tasmina et al. materials and methods the experiment was carried out at the research field of the department of agronomy of bangabandhu sheikh mujibur rahman agricultural university, gazipur during november 2014 to march 2015. the experimental site is mixed with some imported alluvium soil from nearby flood plain and acidic in nature. the soil of the experimental field is belonging to sanla series representing shallow red-brown trace soil type. the climate of the experimental site is subtropical and characterized by scanty rainfall associated with moderately low temperature (21 to 240c) and plenty of sunshine during rabi season (october to march). the experiment was laid out in a split plot design comprising two water regimes (irrigated or control and water stress or water deficit) in main plot and three wheat varieties (bari gom 25, bari gom 26 and sourav) in sub-plot with four replications. after well preparation of land, seeds of @120 kg ha-1 were sown in 20 cm line sowing method on 23 november 2014. n-p-k-s @ 100-60-40-20 kg ha-1, respectively was applied in the form of urea, triple super phosphate, muriate of potash and gypsum. total amount of triple super phosphate, muriate of potash and gypsum were applied during final land preparation. urea was given in two splits, first split of urea was applied during final land preparation and the rest top dressed at 21 das. intercultural operations such as weeding, thinning, gap filling and netting were done when as required. in case of water shortage plots, surface irrigation was applied up to 21 das then it was stopped. data on soil plant analysis development (spad) value, measurement of xylem exudation rate, canopy temperature, light interception, leaf water potential, relative water content, water saturation, retention and uptake capacity were recorded by following procedure: spad value was taken from middle portion of the fully developed flag leaf of the tagged plants with minolta chlorophyll meter (model: spad-502, minolta co. ltd., japan). xylem exudation rate was measured at anthesis stage using following formulae (weight of wheat + sap) (weight of wheat ) xylem exudation rate = ------------------------------------------------------------- time (hr) canopy temperature was measured with an infra-red thermometer and measurements were made within 2 hours of solar noon, and in a south-facing direction to minimize sun angle effects as suggested by turner et al. (1986). light interception (li) at the crop canopy was measured at booting, anthesis, grain filling and physiological maturity stages with a sunfleck ceptometer (decagdn deviceinc., usa) using the following formula i light transmission ratio (ltr) = ----------------------×100 and li % = 100 ltr io where, io=photosynthetically active radiation on the top of the canopy and i= photosynthetically active radiation at the base of the canopy leaf water potential was measured fully expanded flag leaf at booting and anthesis stages using a pressure chamber designed by scholander et al. (1965). relative water content (rwc) was measured at booting, anthesis and grain filling stages. turgid weight (tw) was obtained after soaking leaves in distilled water in beakers for 24 hours at room temperature about (200c) and under the low light condition of the laboratory. dry weight (dw) of the leaf was obtained after oven drying the leaf 107 physiological changes of wheat varieties under water deficit condition samples for 72 hour at 700c. rwc was calculated according to schonfeld et al. (1988): rwc (%) = [(fw-dw)/ (tw-dw)] ×100. measurement of water saturation deficit (wsd), water retention capacity (wrc) and water uptake capacity (wuc) were calculated as follow by sangakkara et al. (1996): wsd (%) = (tw-fw)/ (tw-dw) × 100, wrc = tw/dw and wuc = (tw-fw)/dw where, fw = fresh weight (mg), dw= dry weight (mg), tw = turgid weight (mg) the collection of data was analyzed statistically and the treatment means were adjudged by lsd test (gomez and gomez, 1984) by package program statistix10. results and discussion spad value was used to ascertain the onset of senescence and chlorophyll content of leaf over time. according to manivannan et al. (2007) chlorophyll is one of the major components of chloroplasts for photosynthesis which increases biomass production and grain yield (pandey and singh, 2010). the spad value recorded from 0 days after anthesis (daa) to 28 daa under control and water deficit conditions in three wheat varieties shown in figure 1. fig. 1. spad values of wheat varieties under water deficit condition the spad value progressively increased up to 12 daa under control and water deficit conditions then it was decreased in all varieties except bari gom 25 where it decreases after 8 daa. this might be due to forced senescence of leaf irrespective of varieties. at 12 daa, the highest spad value was recorded in bari gom 26 under both control (57.13) and water deficit (49.53) condition. the lowest spad value was recorded in sourav (54.45) under control condition but under water deficit condition bari gom 25 (42.16) showed the lowest value. water deficits enhanced the senescence by accelerating loss of leaf chlorophyll and soluble proteins and the loss was more in sensitive one than tolerant one (saeedipour, 2012). declined chlorophyll content from 13 to 15% in water-stressed wheat compared with well watered plants (nikolaeva et al., 2010). chlorophyll synthesis was inhibited under water deficit conditions. so, with the decreases of chlorophyll content spad value also decreases. 108 tasmina et al. xylem exudation rate is known as the flow of sap through the cut end of a stem against the gravitational forces. the exudation rate varied both control and water stress condition irrespective of varieties shown in figure 2. fig. 2. xylem exudation rates of wheat varieties under water deficit condition the highest exudation rate was recorded in the var. sourav (33 mg h-1 and 25 mg h-1) which was followed by the var. bari gom 26 (25 mg h-1 and 21 mg h-1), while the var. bari gom 25 (23 mg h-1 and 15 mg h-1) had the lowest exudation rate under both control and water deficit condition. the highest percent of reduction under water stress condition occurred in bari gom 25 and the lowest in bari gom 26. the results agreed with those obtained by baque (2006) who reported that exudation rate is higher in control and lower in moisture stress of wheat. canopy temperature varied significantly among the varieties due to water stress at anthesis stages. the highest canopy temperature under control condition was recorded in sourav (30.830c) which was followed by bari gom 26 (27.730c) and the lowest in bari gom 25 (26.230c) but in water deficit condition the highest canopy temperature was recorded in bari gom 25 (34.380c) which was followed by sourav (32.730c) and the lowest in bari gom 26 (29.090c) (fig. 3). fig. 3. canopy temperatures of wheat varieties under water deficit condition the canopy temperature in wheat varieties increased under water stress condition. this might have occurred due to increased respiration and decreased transpiration as a 0 10 20 30 40 control water stress % reduction e xu da tio n r ate (m g.h -1 ) bari gom 25 bari gom 26 sourav 109 physiological changes of wheat varieties under water deficit condition result of stomatal closure. similar findings reported by siddique et al. (2000) who reported that leaf temperature in drought stressed wheat plant was higher than in well-watered plants at both vegetative and anthesis stages. light interception or interception of photosynthetically active radiation (par) at booting, anthesis, grain filling and physiological maturity stage in wheat canopy under variable water regimes varied significantly shown in figure 4. fig. 4. intercepted par of wheat varieties under water deficit condition under control condition the highest amount of light interception was recorded in bari gom 26 at booting (44.92%) and physiological maturity stage (52.86%) but at anthesis (67.06%) and grain filling (63.60%) stages showed the highest in sourav. incase of water stress, the highest light interception was found in bari gom 26 at booting (34.89%), anthesis (42.45%), grain filling (45.04%) and physiological maturity stage (44.42%). at all the growth stages, the lowest light interception was recorded in bari gom 25 under both conditions. however the highest reduction under water deficit stress was recorded in bari gom 25 while the lowest reduction in bari gom 26 at all the growth stages. canopy radiation interception generally increased throughout the growing season due to increased leaf area. since the leaves temporarily wilted or rolled under the water stress, the radiation interception ability led to being decreased, as observed in the field. similar results obtained by moayedi et al., 2011 and qamar et al., 2011 that accumulated radiation interception was significantly decreased by limited irrigation than frequently irrigated crop plants. leaf water potential (lwp) is considered to be a reliable parameter for quantifying plant water stress response. the leaf water potential is a prominent character that can be selected for improving drought tolerance of different crops (nayyar et al., 2006). the leaf water potential was significantly influenced and decreased markedly in the studied varieties due to water stress at booting and anthesis stages (table 1). table 1. leaf water potential of wheat varieties under water deficit condition wheat variety leaf water potential (-mpa) booting stage anthesis stage in te rc ep te d lig h t (% ) 110 tasmina et al. control water stress % reduction control water stress % reduction bari gom 25 0.74 1.07 30.84 0.75 1.58 52.53 bari gom 26 0.73 0.82 10.97 0.75 1.01 25.74 sourav 0.74 0.9 17.78 0.76 1.19 36.13 cv (%) 4.71, 6.19 8.11, 9.75 lsd (0.05) 0.03 0.067 the highest leaf water potential was recorded in bari gom 26 in booting (-0.73 mpa and -0.82 mpa) and anthesis stages (-0.75 mpa and -1.01 mpa) under both control and water deficit condition, respectively. the lowest leaf water potential was recorded in bari gom 25 in booting stage (-0.74 mpa) but sourav showed the lowest value in anthesis stages (-0.76 mpa) under control condition. in case of water stress condition bari gom 25 (-1.07 mpa and -1.58 mpa) showed the lowest result both at booting and anthesis stages. however, the reduction percent of leaf water potential under water stress was higher in bari gom 25 and lower in bari gom 26. the changes in water potential in wheat might be due to change in osmotic pressure i.e., the osmotic components of water. siddique et al. (2000) reported that drought stress reduced the leaf water potential from -0.63 mpa in control plant and 2.00 mpa in stressed plants. the results obtained in this study were consistent with the result of subrahmanyam et al. (2006) who reported that water deficit stress caused a significant difference in leaf water potential in the tolerant and susceptible genotypes of wheat. relative water content (rwc) indicates that the water status of cells has a significant association with yield and stress tolerance (almeselmani et al., 2012). it is considered a measure of plant water status, reflecting the metabolic activity in tisshues and used as a most meaningful index for dehydration tolerance (anjum et al., 2011). the rwc of flag leaf in studied varieties was measured at booting, anthesis and grain filling stages under water regimes (table 2). table 2. relative water content (%) of wheat varieties under water deficit condition wheat variety booting stage anthesis stage grain filling stage control water stress % reduction control water stress % reduction control water stress % reduction bari gom 25 94.41 83.17 11.97 89.51 76.72 14.29 78.81 60.71 22.97 bari gom 26 96.41 90.15 6.49 87.80 86.27 1.74 78.08 71.94 7.87 sourav 96.93 88.08 9.13 84.71 82.79 2.26 76.62 68.75 10.27 cv(% 3.63, 1.52 6.67, 5.35 5.27, 7.32 lsd(0.05) 4.83 9.13 8.19 the highest relative water content under irrigated condition was observed in sourav (96.93%) at booting stage but during anthesis and grain filling stage bari gom 25 (89.51% and 78.81%) showed the highest value respectively. however bari gom 26 exhibits the highest relative water content at all the stages under water stress condition. the highest reduction occurred in bari gom 25 and the lowest in bari gom 26 at all observed stages under water deficit condition. these results are in 111 physiological changes of wheat varieties under water deficit condition accordance with the findings of farooq et al., 2009 and jaleel et al., 2008 that water deficit in different crop growth stages in different wheat varieties significantly decreased relative water contents. water uptake capacity (wuc) at booting, anthesis and grain filling stage in wheat varieties under variable water regimes varied significantly shown in table 3. table 3. water uptake capacity of wheat varieties under water deficit condition wheat variety booting stage anthesis stage grain filling stage control water stress % increase control water stress % increase control water stress % increase bari gom 25 0.09 0.18 50.50 0.68 1.25 46.00 0.76 1.39 45.14 bari gom 26 0.08 0.11 22.28 0.65 0.80 18.75 0.69 0.90 23.27 sourav 0.09 0.14 35.07 0.63 0.88 28.00 0.86 1.17 26.23 cv(%0 9.61, 21.96 10.95, 22.65 30.65, 24.62 lsd(0.05) 0.04 0.26 0.48 the highest wuc was observed in bari gom 25 at booting (0.09 and 0.18) and anthesis (0.68 and 1.25) stages where it was lowest in bari gom 26 at booting (0.08 and 0.11) and anthesis (0.63 and 0.88) both under control and water stress condition, respectively. at grain filling stage sourav (0.86) showed the highest value and bari gom 26 (0.69) exhibit the lowest value under irrigated condition where bari gom 25(1.39) obtained the highest value and it was lowest in bari gom 26(0.90) under water stress condition. the highest increases in water uptake capacity under water stress occurred in bari gom 25 and the lowest in bari gom 26 at all observed stages. the instantaneous water uptake capacity significantly increased under water stress as compared to the irrigated at studied stages. an increase wuc under water deficit condition was also reported by abbad et al., 2004. similar results were also described by choudhury (2009) and mahmud (2012) that the tolerance varieties possessed the lowest wuc under water stress compared to other varieties. plants grow under high moisture regimes maintain a higher water retention capacity (wrc) which might be due to lower destruction of plant tissues by moisture deficit (sangakkara et al., 1996). wrc was decreased markedly in the studied varieties due to water stress at booting, anthesis and grain filling stages (table 4). table 4. water retention capacity of wheat varieties under water deficit condition wheat variety booting stage anthesis stage grain filling stage control water stress % reduction control water stress % reduction control water stress % reduction bari gom 25 4.15 3.50 15.68 4.87 3.58 26.50 4.74 3.31 30.17 bari gom 26 4.22 4.06 3.81 4.71 4.46 5.27 4.52 4.21 6.76 sourav 4.61 4.32 6.43 4.87 4.42 9.14 4.76 4.18 12.30 cv(%) 7.03, 5.54 13.86, 9.85 7.18, 5.97 lsd(0.05) 0.47 0.95 0.50 112 tasmina et al. the highest wrc was observed in sourav (4.61, 4.87 and 4.76) where it was lowest in bari gom 25 (3.50, 3.58 and 3.31) at booting, anthesis and grain filling stages respectively under irrigated condition. on the other hand, sourav showed the highest (4.32) at booting stage and bari gom 26 showed the highest (4.46 and 4.21) result at anthesis and grain filling stages where bari gom 25 showed the lowest (3.50, 3.58 and 3.31) result at booting, anthesis and grain filling stages under water stress condition. the highest reduction in wrc under water stress occurred in bari gom 25 and the lowest in bari gom 26 at all the studied stages. in the present study, bari gom 26 and sourav showed the lowest reduction in wrc, and thus an indication of their tolerence to drought. similar findings in wrc were reported by choudhury (2009) in french bean and martinez et al. (2007) in phaseolus vulgaris. water saturation deficit (wsd) is the deviation of water content from the leaf compared to the saturation level of that leaf at a particular situation. a higher water saturation deficit indicates that the plants are subjected to a greater degree of water deficit. the present investigation showed a significant difference in wsd in wheat flag leaf at booting, anthesis and grain filling stage under variable water regimes. water deficit significantly increased the wsd in wheat flag leaf irrespective of varieties. regardless of the stages, the lowest wsd was obtained in control plants than stressed ones in all the varieties (table 5). table 5. water saturation deficit (%) of wheat varieties under water deficit condition wheat variety booting stage anthesis stage grain filling stage control water stress % increase control water stress % increase control water stress % increase bari gom 25 13.35 45.04 70.36 16.99 108.20 84.30 18.60 146.54a 87.31 bari gom 26 16.15 19.81 18.47 22.09 29.98 26.34 25.15 38.06c 33.92 sourav 22.11 30.52 27.56 27.60 44.37 37.80 29.86 54.02b 44.72 cv(%) 9.65, 10.16 11.42, 15.21 9.63, 10.95 lsd(0.05) 4.31 9.91 9.53 the highest wsd was observed in sourav (22.11, 27.60 and 29.86 %) where it was lowest in bari gom 25 (13.35, 16.99 and 18.60 %) at booting, anthesis and grain filling stages under irrigated condition, respectively. bari gom 25 showed the highest (45.04, 108.20 and 146.54 %) result and bari gom 26 showed the lowest (19.81, 29.98 and 38.06 %) result at booting, anthesis and grain filling stages under water stress condition. however, the highest increases in water saturation deficit under water stress occurred in bari gom 25 and the lowest in bari gom 26 at all the studied stages. the increasing trend of wsd under water deficit condition was also reported by baque et al. (2006); islam (2008); mahmud (2012) and choudhury (2009). conclusion from the study, it can be concluded that water stress significantly influenced the physiological performance of wheat varieties. the performance of all varieties is better in all respect in irrigated as compared to water stress condition. the variety bari gom 26 is the best performing one under water deficit condition. the wheat var. 113 physiological changes of wheat varieties under water deficit condition sourav could take place after bari gom 26. bari gom 25 was affected more and shows the lowest result under water deficit condition. reference abbad, h., s. e. jaafari, j. bort and j. l. araus. 2004. comparison of flag leaf and ear photosynthesis with grain yield of durum wheat under various water conditions and genotypes. agronomie. 24: 19-28. almeselmani, m., a. saud, k. al-zubi, f. abdullah, f. hareri, m. nassan, m. a. ammar and o. kanbar. 2012. physiological performance of different durum wheat varieties grown under rainfed condition. global j. of sci. frontier res. 12: 55-63. anjum, s., a. anjum, x. xie, l. wang, m. f. saleem, c. man and w. lei. 2011 morphological, physiological and biochemical responses of plants to drought stress. afr. j. agri. res. 6 (9): 2026-2032. araus, j. l., m. p. salfer, c. royo and m. d. serett. 2008. breeding for yield potential and stress adaptation in cereals. critical rev. in plant sci. 27: 377-412. baque, m. a., m. a. karim, a. hamid and h. tetsushi. 2006. effect of fertilizer potassium on growth, yield and nutrient uptake of wheat (triticum aestivum) under water stress conditions. south pacific stud. 27: 25-36. braun, h. j., g. atlin and t. payne. 2010. multilocation testing as a tool to identify plant response to global climate change. in: reynolds mp, ed. climate change and crop production. wallingford, uk: cabi publishers. pp. 115-113. choudhury, a. k. 2009. water stress tolerance of french bean (phaseolus vulgaris l.), ph.d. dissertation. department of agronomy. bangabandhu sheikh mujibur rahaman agricultural university, gazipur, bangladesh. dey, n. c., m. s. alam, a. k. sajjan, m a. bhuiyan, l. ghose, y. ibaraki and f. karim. 2011. assessing environmental and health impact of drought in the northwest bangladesh, j. environ. sci. natur. resour., 4(2): 89-97, 2011. farooq, m., a. wahid, n. kobayashi, d. fujita and s. m. a. basra. 2009. plant drought stress: effects, mechanisms and management. agron. sustain. dev. 29: 185-212. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. int. rice res. inst. john wiley and sons, new york. pp. 139-240. islam, m. s. 2008. water stress tolerance of mungbean [vigna radiata (l.) wilczek] genotypes as influenced by plant growth regulators. a ph. d. dissertation, dept. of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh. jahan, m. a. h. s. 2014. effect of different weed control methods in wheat. research report of wheat research center. pp. 42-46. jaleel, c. a., r. gopi, b. sanker, m. gomathinayagam and r. panneerselvam. 2008. differential responses in water use efficiency in two varieties of catharanthus roseus under drought stress. comp. rend. biol. 331: 42-47. khaliq, i., s. a. h. shah, m. ahsan and m. khalid. 1999. evaluation of spring wheat (triticum aestivum l.) for drought field conditions: a morphological study. pak. j. biol. sci. 2(3):1006-1009. mahmud, a. a. 2012. improvement of drought tolerant potato variety. a ph. d. dissertation. dept. of horticulture, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh. 114 tasmina et al. manivannan, p., c. a. jaleel, b. sanker, a. kishorekumar, r. somassundaram, g. m alagu lakshmanan and r. panneerselvam. 2007. growth, biochemical modifications and praline metabolism in helianthus annuus l. as induced by drought stress. colloids surf. bionierfaces. 59: 141-149. martinez, j. p., h. silva, j. f. ledent and m. pinto. 2007. effect of drought stress on the osmotic adjustment, cell wall elasticity and cell volume of six cultivars of common beans (phaseolus vulgaris l.). eur. j. agron. 26: 30-38. moayedi, a. a., a. n. boyce, s. s. barakbah and m. kafi. 2011. water deficit-induced changes on growth parameters and radiation use efficiency of promising durum wheat genotypes. j. food agric. environ. 9: 563565. nayyar, h., s. kaur, s. singh and h. d. upadhyaya. 2006. differential sensitivity of desi (small-seeded) and kabuli (large-seeded) chickpea genotypes to water stress during seed filling: effects on accumulation of seed reserves and yield. j. sci. food agr. 86: 2076-2082. nikolaeva, m. k., s. n. maevskaya, a. g. shugaev and n. g bukhov. 2010. effect of drought on chlorophyll content and antioxidant enzyme activities in leaves of three wheat cultivars varying in productivity. russ. j. plant physol. 57: 87-95. pandey, r. m. and r. singh. 2010. genetic studies for biochemical and quantitative characters in grain amaranth (amaranthus hypochondriacus l.). plant omics j. 3(4): 129-134. qamar, r., m. ehsanullah, g. munir, mustafa and a. ghafar. 2011. effect of irrigation scheduling on growth, radiation use efficiency and yield of wheat. j. food, agric. environ. 9 (1): 563-565. saeedipour, s. 2012. effect of post-anthesis water deficit on yield and some physiological parameters on two wheat cultivars. afr. j. agric. res. 7: 3446-3452. sangakkara, h. r., u. a. hartwig and j. nosberger. 1996. response of root branching and shoot water potential of phaeseolus valgaris l. to soil moisture and fertilizer potassium. j. agron. crop sci. 177: 165-173. scholander, p. f., h. j. hammel, a. bradstreet and e. a. hemmingsen. 1965. sap pressure in vascular plants. sci. 148: 339-346. schonfeld, m. a., r. c. johnson, b. f. carver and d. w. mornhinweg. 1988. water relations in winter wheat as drought resistance indicator. crop sci. 28: 526-531. siddique, b. m. r., a. hamid and m. s. islam. 2000. drought stress effect on water relation of wheat. bot. bull. aca. 41: 35-39. singh, g. and h. chaudhary. 2006. selection parameters and yield enhancement of wheat (tritium aestivum l.) under different moisture stress condition. asian j. plant sci. 5: 894-898. subrahmanyam, d., n. subash, a. haris and a. k. sikka. 2006. influence of water stress on leaf photosynthetic characteristics in wheat cultivars differing in their susceptibility to drought. photosynthetica. 44(1): 125-129. turner, n. c., j. c. o’toole, r. t. cruz. 1986. response of seven diverse rice cultivars to water deficits. ii. osmotic adjustment, leaf elasticity, leaf extension, leaf death, stomatal conductance and photosynthesis. field crops res. 13: 273-286. bangladesh agron. j. 2018, 21(2): 45-48 effect of planting method on mustard boro inter mixed cropping system s. k. bhowal1*, m. h. hossain2, a. k. m. s. haque 3, a. s. m. m. r. khan4 1scientific officer, onfarm research division, bangladesh agricultural research institute, cumilla, bangladesh 2principal scientific officer, ofrd, bangladesh agricultural research institute, cumilla, bangladesh 3chief scientific officer, farm division, bangladesh agricultural research institute, gazipur, bangladesh 4chief scientific officer, onfarm research division, bangladesh agricultural research institute, gazipur, bangladesh *correspondng, e-mail: shamal.bau@gmail.com (received: 13 february 2019, accepted: 14 march 2019) key words: planting method, mustard boro intercropping, cost and return analysis, bcr abstract a field experiment was carried out at multi location testing (mlt) site, debiddar and chandpur during rabi season of 2015-16 to find out the suitable boro rice planting method with cost and return of inter mixed cropping system in cumilla region. the treatment combinations used were t1 : boro rice (broadcast) + mustard, t2 : boro rice (line sowing) + mustard, t3 : sole mustard, t4 : sole boro rice. results revealed that all the mixed cropping combinations showed superior in terms of gross return, gross margin and rice equivalent yield (rey) than sole cropping. the highest rice equivalent yield (8.52 t ha-1) was found in the treatment combination of boro rice line sowing + mustard. from the cost and return analysis it was observed that the combination of boro rice line sowing with mustard (t2) gave the highest gross return (tk. 127800 ha -1) and gross margin (tk. 77400 ha-1) where sole crop of mustard (t3) gave the lowest gross return (tk. 65120 ha-1) and gross margin (tk. 21450 ha-1) which indicated the advantage of mixed cropping over the sole. introduction mixed cropping of mustard with boro rice is a popular practice in some areas (about 3700 ha) of cumilla and chandpur districts to utilize the residual moisture especially in low lying areas (dae, 2016). the direct seeding of boro rice (oryza sativa) + mustard (brassica campestris) as mixed crop innovative practice is explored by the farmers under aez 19, 22 and 30 (hossain et. al, 2015). this practice is gradually increasing at low laying areas of cumilla region, where only boro rice is being cultivating in whole year. at first farmers’ sowing rice seeds in broadcast method and hereafter they sow mustard seeds. mostly farmers are practicing direct seeded boro rice (var. brri dhan29) as mixed crop with mustard (tori 7) by broadcast method with traditional crop management practices. farmers of these area used different ratio of mustard seeds with 100 % boro rice. most of the farmer’s sowed mustard and boro rice in broadcasting method instead of line sowing. that’s why, intercultural operations like weeding and fertilizer application etc. sometimes makes a problem which resulted low grain yield of rice. so, this experiment was undertaken as a location specific problem oriented program to find out the suitable rice planting method in mustard boro mixed cropping system with cost and return in cumilla region. material and methods 48 bhowal et al. the experiment was carried out at mlt site, debiddar and chandpur during rabi season of 2015-16 to find out the suitable rice planting method in mustardboro inter mixed cropping system with cost and return in cumilla region. the soils of the experimental areas belong to the aezs 19, 22 and 30 (frg, 2012). the soils of the experimental plots were clay loam in texture. the experiment was laid out in randomized complete block design with five dispersed replications. it was consisted with four treatments as follows: t1 : boro rice (broadcast) + mustard, t2 : boro rice (line sowing) + mustard, t3 : sole mustard, t4 : sole boro rice. according to the treatments, seeds of mustard (var. bari sarisha-14) and boro rice (var. brri dhan58) were broadcasted and line sown on 09-11 november 2015 @ 8 and 40 kg ha-1, respectively. the unit plot size was 100 m2. the lands were fertilized with 18.43, 16, 20, 7, 1.43 and 1.36 kg n-p-k-s-zn and b ha-1, respectively. 2/3rds urea and total amount of other fertilizers were applied during final land preparation as basal and rest 1/3rd urea was applied as top dress at 30 days after broadcasting (bari, 2014). plant protection measure and all other management practices were done for mustard and boro rice as and when necessary. mustard was harvested on 04-06 february 2016, whereas boro rice on 24-26 april, 2016. data on the different crop parameters were collected from the 10 randomly selected sample plants and then average was taken which was further analyzed by software program statistix10. rice equivalent yield (rey) and economic analysis were calculated to ascertain the efficiency of intercropping. rice equivalent yield was calculated by converting yield of mixed crops to the yield of rice on the basis of prevailing market prices of individual crops. results and discussions yield and yield attributes of mustard yield attributes and yield of mustard in mustard boro inter mixed cropping situation are presented in the table 1. results indicated that plant populations of mustard were varied with the variation of planting system among the treatments. plant height of bari sarisha-14 showed statistically no significant difference among the treatments in mustard boro intercropping system. it was revealed that the higher number of pods plant-1 (50.78) was recorded in t3 (sole mustard) and lowest number of pods plant-1 (43) was obtained from t1 (boro rice broadcasting + mustard). the highest number of seeds pod-1 (26.50) was recorded in t3 treatment and lowest number of seeds pod-1 (23.60) was recorded in the treatment t1 which was statistically identical with t2. table 1. yields attributes and yield of mustard as a inter mixed crop with boro rice at muradnagar, cumilla and hatila, hajigonj, chandpur, 2015-16 treatments plant population m-2 (no.) plant height (cm) pods plant-1 (no.) seeds pod-1 (no.) seed yield (t ha-1) t1 88.54 99.08 43.00 23.60 1.52 t2 94.14 94.44 47.98 23.72 1.60 t3 97.48 95.84 50.78 26.50 1.64 t4 00 00 00 00 00 lsd (0.05) 6.968 ns 6.629 2.04 0.167 cv % 12.40 6.07 13.57 9.70 10.21 t1 = boro rice (broadcasting) + mustard, t2 = boro rice (line sowing) + mustard, t3 = sole mustard, t4 = sole boro rice effect of planting method on mustard boro 47 seed yield of mustard was higher (1.64 t ha-1) in t3 (sole mustard) followed by t2 (boro rice line sowing + mustard) and the lowest (1.52 t ha -1) was obtained from t1 (boro rice broadcasting + mustard). the seed yield of mustard decreased with the increasing of rice population in the mixed cropped situation might be due to competition for soil nutrients and less light interception between the main and the intercrops compared to sole cropping of mustard. similar relationship in mixed cropping situation was also found by bhowal et al. 2014. yield and yield attributes of boro rice the result indicated that most of the yield attributes of boro rice were significantly influenced due to mixed cropping with mustard (table 2) except plant height, panicle length and number of seeds per panicle. results revealed that plant populations of rice were varied with the variation of planting system among the treatments. the higher number of tiller hill-1 (12.66) was recorded in t4 (sole boro rice) which was statistically identical to t2 and the lower number of tiller hill-1 (10.53) from t1 (boro rice broadcasting + mustard). the highest grain yield of boro was recorded in sole situation t4 (5.16 t ha-1) might be due to cumulative effect of yield contributing characters of boro rice. the lowest grain yield was recorded in the treatment t1 (4.40 t ha -1) where boro rice var. brri dhan58 were broadcasted with mustard. table 2. yield attributes and grain yield of boro rice as a inter mixed crop with mustard at muradnagar, cumilla and hatila, chandpur, 2015-16 treatments plant population m-2 plant height (cm) tiller hill-1 (no.) length of penical (cm) seed penical-1 (no.) grain yield (t ha-1) t1 38.33 84.73 10.53 23.00 220.87 4.40 t2 33.20 87.36 11.06 23.16 223.80 4.79 t3 00 00 00 00 00 00 t4 35.00 84.80 12.66 23.41 224.00 5.16 lsd (0.05) 2.79 ns 3.270 ns ns 0.365 cv % 6.66 0.90 14.51 2.05 2.76 11.46 t1 = boro rice (broadcasting) + mustard, t2 = boro rice (line sowing) + mustard, t3 = sole mustard, t4 = sole boro rice rice equivalent yield (rey) and cost and return analysis rey and cost and return of mustard boro inter mixed cropping system are presented in the table 3. gross return as well as gross margin was found higher in mixed crop cultivation in comparison to sole cropping of mustard and boro rice. from cost and return analysis, it was documented that t2 treatment (boro rice line sowing + mustard) made the highest gross margin tk. 53250 ha1 followed by t1 (tk. 46620 ha -1). table 3. cost and return analysis of mustard boro mixed cropping system at muradnagar, cumilla and hatila, chandpur, 2015-16 treatments rey (t ha-1) total cost ( tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) bcr t1 7.94 72480 119100 46620 1.64 t2 8.52 74550 127800 53250 1.71 t3 3.82 35540 57300 21760 1.61 t4 5.16 56250 77400 21150 1.36 t1 = boro rice (broadcasting) + mustard, t2 = boro rice (line sowing) + mustard, t3 = sole mustard, t4 = sole boro rice, unit price of mustard tk. 35/kg, rice tk. 15/kg, rey= rice equivalent yield 48 bhowal et al. the lower gross margin (tk. 21150 ha-1 and tk. 21760 ha-1) was obtained from sole practices of t3 and t4 respectively. some of research findings also documented higher gross margin or net return in mixed or intercropping system than sole crop (sarker and pal, 2004; razzaque et. al., 2007; alam et. al., 2008). the finding of the research result also supports the findings of farhad et. al. (2014) who reported that intercropping is more profitable than the sole cropping and reduces the risk of mono cropping. farmers’ opinion the farmers obtained more yield and benefit from mustard boro rice as inter mixed cropping (boro rice in line sowing with mustard) than the sole cropping. conclusion considering the yield and economic return it can be concluded that boro rice in line sowing with mustard is the most profitable when grown as mixed crop and risk of cultivation of mono crop can be reduced by mixed cropping. references alom, m. s., paul, n. k., quayyum, m. a. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean in different planting methods. saarc j. agri. 6: 73-82. bari (bangladesh agricultural research institute). 2014. annual research report, on farm research division, gazipur, bangladesh. 276 p. bhowal, s. k, m. m. u. chowdhury, m. s. bhuiyan, a. h. m. a. faisal, i. s. m. farhad and s.k. bhowmik. 2014. yield and yield attributes of lentil (lens esculenta) as a mixed crop with mustard (brassica campestris). sci. agri. 8 (2), 2014: 76-79© psci publications dae (department of agricultural extension). 2016. annual extension report. presented in the regional research-extension review and program planning workshop. khamarbari, cumilla, bangladesh frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka-1215. 274p farhad ism, chowdhury mmu, bhowal sk, choudhury ak, khan asmmr. 2014. chilli – garlic intercropping system in coastal saline area. app. sci. report.psci publications.2 (2): 47-50. hossain, m. h., s. k. bhowal, s. r. haque, m. k. hasan and a. s. m. m. r. khan, 2015, production technology of mustard-boro mixed cropping (bengali booklet). on-farm research division, bari, gazipur, bangladesh. 10p razzaque, m. a., rafiguzzaman, s., bazzaz, m. m. m., ali, a., talukdar, m. m. r. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agril. res. 32 (1): 37-43. statistix 10, analytical software. 2105 miller landing rd. tallahassee fl 32312. usa. email to support@statistix.com sarkar, r. k., pal, p. k. 2004. effect of intercropping rice (oryza sativa) with groundnut (arachis hypogea) and pigeonpea (cajanas cajan) under different row orientations on rainfed uplands. indian j. agron. 49 (3): 147-150. bangladesh agron. j. 2015, 18(2): 65-69 on-farm study on intercropping of hybrid maize with different short duration vegetables in the charland of tangail m. a. rahaman1, m. m. rahman 1, s. roy1, m. ahmed2 and m. s. bhuyan3 1ofrd, bari, tangail 2vertebrate pest division, bari, gazipur and 3agronomy division, bari, gazipur keywords: intercropping, maize (zia mays), vegetables, yield, cost-benefit abstract an experiment was conducted in charland at the multi location testing (mlt) site bhuapur, tangail during 2012-13 and 2013-14 under aez-8 to find out the suitable intercropping system of hybrid maize with different short duration vegetables with economic return. the experiment was laid out in rcb design with six dispersed (six farmers’ field) replications. the hybrid maize (ver. bari hybrid maize-7), potato (diamant), spinach (local), red amaranth (bari lalsak-1), radish (bari mula-1) were used as the planting materials. five treatment combinations viz. t1= sole maize, t2= 100% maize (maize paired row) + potato (var. diamant), t3= 100% maize (maize paired row) + spinach (var. local), t4= 100% maize (maize paired row) + red amaranth (var. bari lalshak-1) and t5= 100% maize (maize paired row) + radish (var. bari mula-1) were studied. maize grain yield in intercropped combination varied from 5.59-7.62 t ha-1. but the highest grain yield (8.17 t ha-1) was obtained from sole maize. maize equivalent yields in the intercrops situation ranged from 11.39-19.68 t ha-1 where highest maize equivalent yield 19.68 t ha-1 was recorded from the treatment t3 (100 % maize + spinach). the same combinations also gave highest gross return (tk. 373930 ha-1) and gross margin (tk. 258585 ha-1) as well as benefit cost ratio (3.24). though highest grain yield was recorded from sole maize but equivalent yield and economic return was much lower than the treatment t3. introduction the area under charland is estimated to be about 0.83 million ha in bangladesh. in tangail district the total charland area is 16,736 ha (dae, 2014). the soil of charland is structure less with poor fertility. farmers used mostly local varieties of crops including boro rice under low management condition. intercropping increases total productivity through efficient utilization of land, labour and growth resources (ahmed et al., 2006). greater productivity in intercropping system is commonly achieved by minimizing interspecific competition and maximizing complementary use of growth resources (islam, 2002). inter-specific competition may be minimized through judicious choice of crops (santalla et al., 2001). usually plants differing in growth duration, height, rooting systems and nutrient requirements are considered to grow together in intercropping systems (reddy and willey, 1981). at present maize is a very popular and multi uses cereal crop. besides, the climate of bangladesh is suitable for maize cultivation. the rate of seed germination and seedling growth of maize are very slow in winter season due to prevailing low temperature. farmers grow maize as a sole crop at the charland area of bhuapur, tangail. in that area fodder for livestock and poultry feed is acute problem. every year a huge amount of maize grain is required as feed and fodder for poultry and livestock sector and most of them imported. 66 rahaman et al. maize is a long duration crop which takes about five months so, short duration vegetable crops like red amaranth, radish, spinach, potato could be grown in between maize rows at early stages to get quick return. vegetable are the main component of human food that supplies proteins, carbohydrates, fats, vitamins and minerals. at present vegetable production is much less than the requirement. however, there is a limited scope for bringing additional land for vegetable cultivation. so, alternate option is to grow vegetables per unit area through intercropping system. hence, this experiment was designed to study the feasibility and agro-economic performance of maize intercropping with different short duration vegetable crops. materials and methods the experiment was conducted at mlt site bhuapur, tangail during rabi season of two consecutive years of 2012-13 and 2013-14 under aez#8. the experiment was laid out in a randomized complete block design with six dispersed (six farmers’ field) replications. five treatment combinations viz. t1= sole maize, t2= 100 % maize (maize paired row) + potato (var. diamant), t3= 100 % maize (maize paired row) + spinach (var. local), t4= 100 % maize (maize paired row) + red amaranth (var. bari lalshak-1) and t5= 100 % maize (maize paired row) + radish (var. bari mula-1) were studied. the unit plot size was 8 m × 5 m. three rows (45 cm x 20 cm) of potato, spinach (broadcast), red amaranth (broadcast) and four rows (30 cm x 10 cm) of radish were sown in between paired rows of maize (maize paired row spacing was 150 cm, line to line spacing 37.5 cm and plant to plant 25 cm). the spacing for sole and intercropping maize was 75 cm × 25 cm. maize, potato, spinach, red amaranth and radish seeds were sown during 20-27 november, 2012 and 25-30 november, 2013. fertilizers were applied @ 255-55-140-40-6-2 kg ha-1 n-p-k-s-zn-b for maize. 1/3 n and full amount of other fertilizers were applied as basal. rest n was applied in maize rows as top dress in two equal splits at 30 and 60 days after sowing (das). subsequently three irrigations were applied at 20, 30 and 60 das. earthling up was done at 30 days after planting potato. two hand weeding were done at 20 and 35 das to keep the crop weed free. the main crop (maize) was harvested from 23 april to 2 may, 2013 and 15-20 april, 2014. the intercropped vegetables such as potato, spinach, red amaranth and radish were harvested at 90-94, 31-42, 27-41 and 50-66 das, respectively in both cropping season. yield component data of crops were collected prior to harvest from each plot. data of two years were analyzed statistically and mean comparison was done by lsd test. the relative yield was obtained by dividing the intercrop yield of a crop with the respective sole crop yield of that crop using the formula (dewit and vander bergh, 1965). the relative yield of a crop = maize equivalent yield was calculated by converting the yield of red amaranth, radish, spinach, potatointo the yield of maize on the basis of prevailing market price using the formula of anjaneyulu et al. (1982). benefit cost analysis were also done. maize equivalent yield (for vegetables) = ym= yield of maize, pm= sales price of maize, yint = yield of intercrop (potato, spinach, red amaranth and radish). results and discussion 67 on-farm study on intercropping of hybrid maize effect on yield and yield components of maize yield and yield contributing characters of intercropped maize were statistically significant (table 1). the highest plant height 189.60 cm was recorded from sole maize and the lowest plant height 148.27 was obtained from maize + radish intercropping combination. the highest number of grains cob-1 502.93 was recorded from sole maize plot and the lowest number of grains cob-1 371.60 was found in maize + radish intercropping combination. the same trend was observed in case of 1000grain weight and it was ranged from 291.70324.60 g in different treatments. the highest 1000grain weight 324.60 g was recorded from sole maize and the lowest 1000grain weight 291.70 was obtained from maize + radish intercropping combination. the highest grain yield (8.17 t ha-1) was recorded from sole maize, which could be due to higher no. of grains cob-1 and 1000 grain weight. the grain yield of maize in intercropped combination varied from 5.59-7.62 t ha-1. the yield data indicated that due crop competition in intercropping yield loss of maize was observed. effect of intercrops the intercrop yield of potato, spinach, red amaranth and radish were influenced significantly by different intercropping combinations (table 2). the highest vegetable yield was recorded from radish in maize + radish intercropping combination (22.03 t ha-1) followed by spinach combination (19.65 t ha-1). the lowest yield was obtained from red amaranth in maize + red amaranth intercropping combination (7.40 t ha-1). relative yield relative yield determines competitive ability of component crops in intercropping system. greater value of relative yield showed more competitive ability in intercrop situation compared to its monoculture (juskiw et al., 2000). the relative yields of maize were 0.93, 0.89, and 0.89 and 0.68 when maize was intercropped with potato, spinach, red amaranth and radish, respectively (table 2). this indicates that maize yield was reduced by 6.73%, 11.02%, 11.38% and 31.58% as compared to sole crop when it was intercropped with potato, spinach, red amaranth and radish, respectively. it indicates that potato yield was adversely affected and less by growing radish. the lower relative yield of maize in intercropping indicated that the crop faced competition for space, nutrients, light, and water. the findings are in agreement with that of hossain et al. (2015). maize equivalent yield all the intercropped combinations showed higher maize equivalent yield than sole maize in all cases. among the treatments, the highest maize equivalent yield (19.68 t ha-1) was obtained from maize + spinach intercrop combination (table 2). the lowest maize equivalent yield (11.39 t ha-1) was obtained from maize + radish intercrop combination. although maize yield was 6.73, 11.02, 11.38 and 31.58 % lower than sole crop when it was intercropped with potato, spinach, red amaranth and radish. but maize equivalent yield from maize + potato, maize + spinach, maize + red amaranth and maize + radish intercrop combination showed 77.92, 140.89, 45.72 and 39.36 % higher yield advantage over the sole maize respectively. this result showed that maize + spinach was the best intercrop combination in respect of total yield advantage. cost return analysis an analysis on cost and return of intercropping maize with different short duration vegetables has been presented in table 3. higher gross return was obtained from all intercrop combinations than sole crop. among the combinations, the highest gross return (tk. 37390. 68 rahaman et al. ha-1) was obtained from maize + spinach intercropping system, which was 140.89 % higher than sole maize (tk. 155230. ha-1). among the intercrop combinations the lowest gross return (tk. 216335 ha-1) was found form maize + radish intercrop. almost similar trend was followed in case of gross margin. the highest benefit-cost ratio (3.24) was recorded from maize + spinach combination due to yield and economic advantage but maize + potato can be grown through potato yield reduced substantially. table 1. yield and yield contributing characters of maize and yield of vegetables under intercropping situation in charland bhuapur, tangail maize grain yield (t ha-1) vegetable yield (t ha-1) treatmen t plant height (cm) grains cob-1 (no.) 1000grain wt. (g) 2012-13 2013-14 mean 2012-13 2013-14 mean t1 189.60 502.93 324.60 8.11 8.23 8.17 t2 183.93 484.45 319.07 7.51 7.73 7.62 13.48 12.80 13.14 t3 171.65 483.83 312.62 6.97 7.57 7.27 21.02 18.28 19.65 t4 173.47 478.02 311.73 7.24 7.23 7.24 7.92 6.87 7.40 t5 148.27 371.60 291.70 5.11 6.07 5.59 21.32 22.73 22.03 lsd (0.05) 11.27 17.49 4.65 0.18 0.35 0.45 1.17 cv (%) 5.40 3.10 1.20 2.08 3.90 2.93 8.00 t1= sole crop of maize (100% maize) t2= 100% maize (maize paired row) + potato (diamant) t3= 100% maize (maize paired row) + spinach t4= 100% maize (maize paired row) + red amaranth (bari lalshak-1) t5= 100% maize (maize paired row) + radish (bari mula-1) table 2. maize grain yield, vegetable yield, maize relative and equivalent yield influenced by intercropping with vegetables at bhuapur, tangail treatment maize grain yield (t ha-1) vegetable yield (t ha-1) relative yield of maize maize equivalent yield (t ha-1) t1 8.17 8.17 t2 7.62 13.14 0.93 14.54 t3 7.27 19.65 0.89 19.68 t4 7.24 7.40 0.89 11.91 t5 5.59 22.03 0.68 11.39 table 3. cost and return analysis of maize intercropping with vegetables at bhuapur, tangail treatment gross return (tk. ha-1) cost of production (tk. ha-1) gross margin (tk. ha-1) benefit-cost ratio (bcr) t1 155230 84350 70880 1.84 t2 276180 121650 154530 2.27 t3 373930 115345 258585 3.24 t4 226205 112170 114035 2.02 t5 216335 109575 106760 1.97 price (tk. kg-1): maize=19/-, potato = 10/-, spinach = 12/-, red amaranth = 12/and radish = 5/farmers’ opinion: maize with short duration intercrops (potato, spinach, red amaranth and radish) was observed as a profitable practice in char land area. as such they can earn extra income easily without hampering the main crop (maize) yield and can help to meet up the vegetable requirement of the family of char land area where acute problems of vegetables. 69 on-farm study on intercropping of hybrid maize conclusion from the results, it revealed that maize grown as intercrop with short duration vegetables like potato, spinach, red amaranth and radish may be profitable than sole maize. all of the intercrop combinations are agronomically and economically viable than sole cropping. but, he results suggested that the possibility of obtaining a reasonably good yield and profitable economic return from intercropping maize with spinach in char land area of bhuapur, tangail. references ahmed, f., m. a. rahman, m. a. h. s. jahan, m. ahmed and m. a. khayer. 2006. effect of different planting systems in maize/spinach-red amaranth intercropping. bangaldesh j. agric. and environ. 2(2): 69-76. anjaneyulu, v. r., s. p. singh and m. pal. 1982. effect of competition free period and technique and pattern of pearmillet planting on growth and yield of mungbean and total productivity in solid pearlmillet and pearlmillet and pearlmillet/mungbean intercropping system. indian j. agron.27(3):219-226). dae. 2014. area and production of major crops and major cropping pattern of tangail district. department of agricultural extension (dae), tangail, bangladesh. may 2014. dewit, c. t. and j. p. vander bergh. 1965. competition between herbage plants. neth. j. agric. sci. 13: 212-221. hossain, m. h., s. k. bhowal and a. s. m. m. r. khan. 2015. intercropping system of maize with different winter vegetables. malays. j. med. boil. res. 2: 153-156. isalm, m. n. 2002. competitive interference and productivity in maize-bushbean intercropping system. a phd. dissertation, dept. of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur. juskiw, p. e., j. h. helim and d. f. salman. 2000. competitive ability in mixtures of small grain cereals. crop sci. 40: 159-164. reddy, m. s and r. w. willey. 1981. growth and resource use studies in an intercrop of pearl millet/groundnut. field crops res. 4: 13-24. santalla, m., a. p. rodino, p. a. casquero and a. m. de ron. 2001. interactions of bushbean intercropped with field and sweet maize. european j. agron. 15: 185-196. bangladesh agron. j. 2015, 18(1): 37-48 performance of prilled urea and urea super granules on the growth and yield of wheat l. nahar1, m. h. ali2, s. m. masum2, m. m. mahbub3 and s. r. haque4 1scientific officer, agronomy division, bangladesh rice research institute, gazipur-1701 2department of agronomy, sher-e-bangla agricultural university, dhaka-1207 3scientific officer, agronomy division, bangladesh rice research institute, gazipur-1701 4scientific officer, bangladesh agricultural research institute, gazipur-1701 key words: prilled urea, urea super granules, growth and yield, wheat abstract an experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka-1207 during the period from november 2011 to march 2012 to evaluate the performance of prilled urea and urea super granules (usg) on the growth and yield of wheat varieties. the experiment comprised of four wheat varieties viz., bari gom 21, bari gom 24, bari gom 25 and bari gom 26, and five nitrogen (n) levels viz., control (no nitrogen), 84 kg ha-1 n from usg, and 30, 50 and 70 kg n ha-1 from prilled urea i.e., 67, 112 and 155 kg urea ha-1. the experiment was laid out in a split-plot design with three replications where wheat varieties were placed in the main plot and nitrogenous fertilizers in sub-plots. experimental results indicated that different varieties had the significant effect on plant height, number of tillers and dry weight plant-1, and number of grains spike-1, grain and straw yield, and harvest index. the variety bari gom 24 produced the highest grain yield (2.49 t ha-1) that mainly attributed by the maximum number of spikes plant-1, number of grains spike-1 and 1000-grain weight. among the different nitrogenous fertilizers 84 kg n ha-1 from usg (1.8 g) gave the highest grain yield (2.69 t ha-1) due to the maximum number of spikes plant-1, maximum number of grains spike-1 and 1000-grain weight. the variety bari gom 24 produced the highest grain yield (2.80 t ha-1) with 80 kg n ha-1 from usg application. introduction wheat (triticum aestivum l.) is ranked first both in acreage and production among cereal crops in the world but second most important stable food crop in bangladesh.. scarcity of food may become a chronic problem in future. to mitigate the food shortages, measures should be taken to increase the total food production. so, the yield of wheat will be needed to increase to boost up its production wheat cultivation is easier and requires less time and irrigation than other alternative crops like boro rice, legumes and potato; additionally it needs low cultivation cost. the crop is grown under different environmental conditions ranging from humid to arid, sub tropical to temperate zone (saari, 1998). the area under wheat cultivation during 2007-2008 was about 5.59 lakh hectares producing 9.76 lakh tons of wheat with an average yield of 1.75 ton per hectare (bbs, 2008). however, wheat production has generally stagnated due to high cost of production and low level of technology (onsongo, 2003). proper using techniques and doses of fertilizers are mostly important for better growth for any crops. among the fertilizers, n plays a vital role in producing higher grain yield. . rate of n application has a great influence on growth, development and yield of wheat. wheat yield increases with the increase of nitrogenous fertilizer (singh et al., 1986). grain yield of wheat increases with increasing n level up to 120 kg ha-1 (malik, 1981 and sarker et al., 1997). prilled urea is a fast releasing 38 nahal et al. nitrogenous fertilizer which is usually broadcast in splits, that causes considerable loss as ammonia volatilization, immobilization, denitrification and surface run off etc. on the other hand, deep placement of slow releasing nitrogenous fertilizer such as usg reduces loss as well as increases its use efficiency in dry land rabi crops (islam et.al., 2011). proper application of usg can increase yields and fertilizer-n utilization of wheat and simultaneously decrease n losses compared to equivalent use of prill (khalil et al., 2011). therefore, the present experiment was conducted tofind out the effect of prilled urea and usg on the growth and yield of wheat as well asfind out the optimum dose of nitrogenous fertilizer for the variety materials and methods the experiment was carried out at the agronomy field, sher-e-bangla agricultural university, dhaka-1207 during the period of 14 november 2011 to 15 march 2012. the soil of the experimental site was clay loam belonging to the aez 28 (madhupur tract). the selected plot was medium high land. and above flood level soil samples from 0-15 cm depth were collected from experimental plot. details of the soil analysis have been shown in table 1. table 1. chemical properties of soil in the study area soil characteristics analytical value ph 5.47-5.63 organic matter (%) 2.01 total n (%) 0.20 available p 22 ppm exchangeable k 0.42 meq/100 g soil the experiment comprised of wheat varieties and n levels, and was laid out in a split-plot design with three replications. four wheat varieties viz., bari gom 21 (v1), bari gom 24 (v2), bari gom 25 (v3) and bari gom 26 (v4) were assigned to the main plots, while five n levels viz., control (no nitrogenous fertilizer) (n0), 84 kg n ha-1 from usg (n1), 30 kg n ha-1 from prilled urea (n2), 50 kg n ha-1 from prilled urea (n3) and 70 kg n ha-1 from prilled urea (n4) were assigned to the sub-plots. usg (two pieces 0.9 g each) was placed i.e., 50 and 20 cm distance in rows and plants, respectively. the unit plot size was 3m 3 m. the land was prepared with power tiller on 12 november 2011. a blanket dose of manures and fertilizers were applied @ 3,000-30-10-24-5 kg ha-1 cowdung-nitrogen-tsp-mop-gypsum (frg, 2005). the whole amount of tsp, mop, gypsum and two-third of prilled urea (except for control treatment) were incorporated in each plot at the time of final land preparation. rest one-third of prilled urea was applied at crown root initiation (cri) stage i.e., 21 days after sowing (das). usg was applied only once at a time into the field at cri stage after irrigation. at a good tilth condition, furrows were made 25 cm apart with hand rakes for sowing. before sowing, seeds were treated with provax 200 @ 2.5 g powder for 1 kg seed. seeds were sown continuously in lines on 14 november 2011 @ 125 kg ha-1. after sowing, the seeds were covered with soil and lightly pressed by hand. intercultural operations were done to ensure normal growth of the crop. three irrigations were applied at 21, 45 and 62 das i.e., at cri stage, heading stage and grain filling stage, respectively. weeding was done twice at 20 and 40 das. during the irrigation care was taken so that water could not flow from one plot to another or overflow the boundary of the plot. the varieties bari gom 21, 24, 25 and 26 were harvested on 04 march, 28 february, 28 february and 01 march 2012, respectively at physiological maturity. 39 performance of prilled urea and usg on the growth and yield of wheat prior to harvest, five hills from each plot were selected randomly (excluding border hills) to collect the data on plant characters, yield attributes and yield. biological yield was calculated from the following formula. biological yield (t ha-1) = grain yield (t ha-1) + straw yield (t ha-1). harvest index was calculated as the ratio of economic yield (grain yield) to biological yield and expressed in terms of percentage. it was calculated by using the following formula (donald, 1963). harvest index (%) = x 100 the collected data on each plot were statistically analyzed and mean difference among the treatments were tested with the least significant difference (lsd) at 5 % level of significance. results and discussion effect of variety the effect of variety on plant height was significant at all sampling dates such as 15, 30, 45, 60, 75, 90 das and at harvest (fig. 1). the variety bari gom 21 produced the tallest plants (94.9, 97.9 and 99.4 cm at 75, 90 das and at harvest, respectively) which was superior to all other varieties. but at 15, 30, 45 and 60 das the variety bari gom 25 produced the maximum plant height (33.1, 36.5, 56.9 and 88.2 cm, respectively) which was statistically similar to the variety bari gom 26 at 30 das. on the other hand, the variety bari gom 21 was shorter than other varieties from 15 das to at 60 but it was observed that at 75, 90 das and at harvest the variety bari gom 24 produced the shorter plants (90.3, 91.9 and 91.9 cm, respectively). the results obtained from the present study were conformity with the findings of tariq (2010), rahman et al. (2009). the result revealed that the effect of variety on number of tillers plant-1 was significant at all sampling dates (fig. 2). the variety bari gom 24 produced the maximum number of tillers plant-1 (2.9, 3.5, 3.5, 4.3, 4.9, 4.9 and 4.6 at 15, 30, 45, 60, 75, 90 das and at harvest, respectively) which was statistically similar with the variety bari gom 21 at 30, 45, 75 das and at harvest. results also showed that the variety bari ghom 26 was statistically similar to the variety bari gom 24 at 15, 30 and 60 das. on the other hand, the variety bari gom 21 produced the minimum number of tillers plant-1 at 15 das (2.53) but at 30, 45, 60, 75, 90 das and at harvest the variety bari gom 25 produced the minimum (2.91, 3.07, 4.07, 4.78, 4.35 and 4.36, respectively) which was identical to the variety bari gom 26 at 45 das and at harvest. the results obtained from the present study were similar to the findings of nadim et al. (2012), hussain et al. (2010) and tariq (2010). significant variation was observed in dry weight plant-1 at all sampling dates (fig. 3). results indicated that at 30 das, variety had no significant effect but at 60, 90 das and at harvest and the variety bari gom 24 produced significantly higher dry weight plant-1 (6.34, 15.48 and 18.19 g, respectively). results also showed that the variety bari gom 25 produced the lowest dry weight plant-1 at 30, 60, 90 das and at harvest (5.8, 13.8 and 16.9 g, respectively) which was statistically similar to the variety bari gom 21 and bari gom 26 at the time of harvest. grain yield biological yield 40 nahal et al. v1= bari gom 21, v2= bari gom 24, v3= bari gom 25 and v4= bari gom 26 fig. 1. plant height as influenced by four improved varieties of wheat at different growth stages during november’ 2011 to march’ 2012. lsd(0.05)= 0.72, 0.58, 0.78, 0.80, 0.68, 0.80 and 0.82 at 15, 30, 45, 60, 75 das and at harvest, respectively. v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26 fig. 2. tiller number per hill as influenced by four improved varieties of wheat at different growth stages during november’ 2011 to march’ 2012. lsd(0.05)= 0.35, 0.37, 0.31, 0.13, 0.12, 0.08 and 0.11 at 15, 30, 45, 60, 75, 90 das and at harvest, respectively. v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26 fig. 3. dry weight plant-1 as influenced by four improved wheat varieties during to november’ 2011 to march’ 2012. lsd(0.05)= ns, 0.24, 0.32 and 0.28 at 30, 60, 90 das and at harvest, respectively 41 performance of prilled urea and usg on the growth and yield of wheat number of spikelets spike-1 was significantly influenced by different varieties (table 2). the highest number of spikelets spike-1 was found in variety bari gom 24 and the lowest in bari gom 25. similar results were found by nadim et al. (2012), hussain et al. (2001) and rahman (2009). number of grains spike-1 was significantly influenced by different varieties where highest number of grains spike-1 (37.10) was found in bari ghom 24and the lowest number of grains spike-1 (33.50) in bari gom 25 (table 2). the results were similar with the findings of rahman et al. (2009), and sikder et al. (2001). weight of 1000 grains was significantly influenced by different varieties where highest 1000-grain weight (58.66 g) was found in bari gom 25 and the lowest weight (52.68 g) in bari gom 21. grain yield was significantly influenced by different varieties and the highest grain yield (2.49 t ha-1) was found in bari gom 24) which was statistically similar to bari ghom 26. on the other hand the lowest grain yield (2.28 t ha-1) was found in bari ghom 25 which was statistically similar to bari gom 21. straw yield was significantly influenced by different varieties and maximum straw yield (3.57 t ha-1) was found in bari gom 21 which was statistically similar to bari gom 24 and bari ghom 25. on the other hand the lowest straw yield (3.53 t ha-1) was found in bari ghom 26). similar result was found by hussain et al. (2010). results showed that the maximum harvest index (41.08%) was found in bari gom 24 which was statistically similar to bari ghom 26 and the lowest (39.00%) in bari gom 25 but similar to bari gom 21. table 2. yield and yield contributing parameters and harvest index of wheat as influenced by variety variety number of spikelets spike-1 number of grains spike-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) v1 16.66 36.15 52.68 2.32 3.57 39.29 v2 17.23 37.10 58.11 2.49 3.55 41.08 v3 15.72 33.50 58.66 2.28 3.55 39.00 v4 16.61 36.30 56.31 2.43 3.53 40.69 lsd (0.05 ) 0.29 0.64 0.321 0.096 0.033 1.213 cv (%) 6.34 4.60 6.78 10.4 9.56 9.20 v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26 effect of n level and source of n the plant height differed significantly among the different nitrogenous fertilizer at all sampling dates (fig. 4). the tallest plant was found in 100 kg n ha-1 from prilled urea (at all sampling dates (32.9, 36.3, 54.3, 88.0, 92.5, 95.6 and 94.9 cm at 15, 30, 45, 60, 75, 90 das and at harvest, respectively). on the other hand, the shorter plant was found in control (n0) treatment throughout the growing season but at 15 das, the shortest plant was found in 120 kg n ha-1 from prilled urea (n4). the result obtained from the present study was conformity with the findings of rahman (2005) and akter (2005). significant variation was observed on number of tillers plant-1 in case of different forms of n application in the field (fig. 5). it was found that the maximum number of tillers plant-1 was found in 80 kg n ha-1 from usg (n1) at all sampling dates which was statistically similar to n4 at 60, 75 das and at harvest. on the other hand, the lowest number of tillers plant-1 (2.41, 2.89, 3.00, 3.94, 4.55, 3.76 and 3.41 at 15, 30, 45, 60, 75, 90 das and at harvest, respectively) was found in control which was statistically similar to 80 kg n ha-1 from prilled urea at 75 das and to n3 at 60 das. significant variation was observed on dry weight plant-1 in case of different forms of nitrogenous fertilizer 42 nahal et al. application in the field (fig. 6). it was found that the highest dry weight plant-1 was found in n1 treatment at all sampling dates (0.62, 7.40, 17.64 and 20.40 g at 30, 60, 90 das and at harvest, respectively). on the other hand, the minimum dry weight plant-1 (0.21, 4.11, 9.61 and 10.80 g at 30, 60, 90 das and at harvest, respectively) was found in control. n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 30 kg n ha-1 from prilled urea, n3 = 50 kg n ha-1 from prilled urea and n4= 70 kg n ha-1 from prilled urea fig. 4. plant height as influenced by urea super granules (usg) and prilled urea on growth of improved wheat varieties from november’ 2011 to march’ 2012. lsd(0.05)= 0.66, 0.54, 0.73, 0.86, 0.71, 0.83 and 0.88 at 15, 30, 45, 60, 75, 90 das and at harvest, respectively n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 30 kg n ha-1 from prilled urea, n3 = 50 kg n ha-1 from prilled urea and n4= 70 kg n ha-1 from prilled urea fig. 5: effect on number of tillers plant-1 as influenced by urea super granules (usg) and prilled urea on growth of improved wheat varieties from november’ 2011 to march’ 2012. lsd(0.05)= 0.29, 0.32, 0.34, 0.13, 0.23, 0.091 and 0.24 at 15, 30, 45, 60, 75, 90 das and at harvest, respectively 43 performance of prilled urea and usg on the growth and yield of wheat n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 30 kg n ha-1 from prilled urea, n3 = 50 kg n ha-1 from prilled urea and n4= 70 kg n ha-1 from prilled urea fig. 6. dry weight plant-1 as influenced by urea super granules (usg) and prilled urea on growth of improved wheat varieties from november’ 2011 to march’ 2012. lsd(0.05)= 0.069, 0.27, 0.35, and 0.31 at 30, 60, 90das and at harvest, respectively significant variation was observed in number of spikelets spike-1 in case of different forms of n application (table 3). the highest number of total spikelets spike-1 (20.63, 1.05 and 21.76, respectively) were achieved from usg application and the lowest number of total spikelets spike-1 (9.43, 4.70 and 13.89, respectively) was found in n0 (control). similar results were found by hossain et al. (2005) and mozumder (2001). significant variation was observed on number of grains spike-1 and the highest number of grains spike-1 (44.05) was achieved from usg application. on the other hand, the lowest number of grains spike-1 (24.86) was found in n0 (control). significant variation was observed on 1000-grain weight in case of different forms of n application where the highest 1000-grain weight (64.66 g) was achieved from usg application and the lowest 1000-grain weight (45.26 g) was found in n0 (control). significant variation was observed on grain yield in case of different forms of n application where highest grain yield (2.69 t ha-1) was achieved from usg application with 80/84 kg ha-1. on the other hand, the lowest grain yield (1.97 t ha-1) was found in n0 (control). the results obtained from the present study was conformity with the findings of rahman (2005), akter (2005) and yadav et al. (2005). the maximum straw yield (3.59 t ha-1) was achieved from usg which was statistically similar to 80-120 kg n ha-1 from prilled urea while the lowest straw yield (3.43 t ha1) was found in n0 (control). the highest harvest index (43.96%) was achieved from usg application and the lowest harvest index (35.69%) was found in n0 (control). interaction effect of variety and nitrogen the plant height differed significantly due to the interaction effect of variety and different nitrogenous fertilizer at all sampling dates (table 4). results showed that the maximum plant height was obtained from v3n3 at 15, 30, 45 and 60 das (34.5, 40.7, 59.3 and 90.1, respectively) which was statistically similar to v2n3 and v3n0 at 15 and 60 das and v3n4 at 60 das. but at 75, 90 das and at harvest the tallest plant was obtained from v1n3 (98.2, 100.4 and 100.7 cm, respectively). on the other hand the shortest plant (30.0 cm) was obtained from v2n4 combination at 15 das, but at 30, 45 and 60 das, the shortest plant 44 nahal et al. inv1n0 combination and at 75, 90 das and at harvest, the shortest plant was obtained fromv2n0 combination. table 3. yield and yield contributing parameters and harvest index of wheat varieties as influenced by prilled urea and usg treatments number of spikelets spike-1 number of grains spike-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) n level and source of n n0 9.43 24.9 45.3 1.9 3.43 35.7 n1 20.6 44.0 64.7 2.7 3.60 43.9 n2 17.8 36.5 56.8 2.4 3.60 40.2 n3 17.5 36.5 57.9 2.3 3.60 39.2 n4 17.4 36.7 57.6 2.5 3.60 41.0 lsd (0.05 ) 0.31 1.23 0.32 0.11 0.03 1.06 cv (%) 8.87 10.2 5.90 11.0 8.51 7.10 n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 30 kg n ha-1 from prilled urea, n3 = 50 kg n ha-1 from prilled urea and n4= 70 kg n ha-1 from prilled urea table 4. plant height of wheat varieties as influenced by interaction of variety and prilled urea or urea super granules (usg) at different dates from november 2011 to march 2012 interaction (variety x nitrogen) plant height (cm) at different days after sowing 15 30 45 60 75 90 at harvest v1n0 32.3 32.6 47.2 82.2 95.2 95.9 93.6 v1n1 31.1 34.1 49.3 84.6 94.1 97.4 96.9 v1n2 31.0 36.7 52.3 86.2 95.0 97.2 96.6 v1n3 30.3 34.6 47.8 87.5 98.2 100.4 100.0 v1n4 32.5 35.3 52.5 85.4 92.3 98.83 97.8 v2n0 32.4 35.8 57.7 86.1 86.8 86.5 85.8 v2n1 33.9 36.2 51.8 88.2 93.3 95.6 92.3 v2n2 30.9 35.4 53.8 85.8 89.7 91.3 91.1 v2n3 34.5 34.7 54.4 89.8 89.8 92.2 91.4 v2n4 30.0 32.9 54.4 86.0 91.9 94.3 92.3 v3n0 34.4 36.8 48.1 89.6 91.5 91.9 96.2 v3n1 30.6 33.4 56.9 86.0 89.4 92.7 93.7 v3n2 34.3 37.0 52.5 85.1 90.4 93.2 92.2 v3n3 34.5 40.7 59.3 90.1 91.8 95.7 92.9 v3n4 31.5 36.2 54.6 89.9 91.2 92.2 91.1 v4n0 32.2 35.7 55.4 85.6 89.5 90.3 91.2 v4n1 32.0 34.5 57.1 85.6 90.6 91.9 92.5 v4n2 31.1 35.2 58.7 84.8 93.8 96.7 92.3 v4n3 32.8 35.5 56.4 84.7 93.3 94.1 99.2 v4n4 33.2 39.1 54.9 87.2 88.3 90.8 92.8 lsd (0.05 ) 0.35 0.57 1.64 1.00 1.31 1.38 1.40 cv (%) 8.17 10.4 10.5 7.12 8.33 9.00 9.44 v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26; n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 30 kg n ha-1from prilled urea, n3 = 50 kg n-1 from prilled and n4= 70 kg n ha-1 from prilled urea 45 performance of prilled urea and usg on the growth and yield of wheat number of tillers plant-1 was significantly influenced by the interaction of variety and nitrogenous fertilizer at different das (table 5). results showed that the maximum number of tillers plant-1 was obtained from v2n1 at 15, 30, 45, 60, 75, 90 das and at harvest (3.5, 4.0, 4.4, 4.8, 5.4, 5.8 and 5.8, respectively) which was statistically similar with v4n2 and v4n3 at 30 das and 75 das, respectively. on the other hand the minimum number of tillers plant-1 at 15, 30, 45, 60, 75, 90 das and at harvest was observed as 2.3, 2.6, 2.7, 3.4, 4.3, 3.5 and 3.3, respectively, with v3n0 which was statistically similar to v1n0 at 15 and 60 das. table 5. number of tillers plant-1 as influenced by interaction of variety and prilled urea or urea super granules (usg) during the period from november’ 2011 to march’ 2012 interaction (variety x nitrogen) number of tillers plant-1 at different days after sowing 15 30 45 60 75 90 at harvest v1n0 2.3 2.9 3.2 3.6 4.8 4.1 3.6 v1n1 3.1 3.7 3.4 3.9 4.7 4.9 4.9 v1n2 2.9 3.4 3.0 4.3 4.8 4.1 3.8 v1n3 2.5 3.4 3.3 3.9 4.7 4.5 4.6 v1n4 3.0 3.7 3.9 4.6 4.6 4.8 4.8 v2n0 2.4 2.9 3.1 4.1 4.9 3.9 3.4 v2n1 3.5 4.0 4.4 4.8 5.4 5.8 5.8 v2n2 2.6 3.3 3.7 4.4 5.2 4.9 4.8 v2n3 2.8 2.8 3.1 3.8 5.1 4.8 4.7 v2n4 2.3 2.7 3.6 4.4 5.1 5.2 5.1 v3n0 2.3 2.6 2.7 3.4 4.3 3.4 3.3 v3n1 2.7 3.7 3.2 4.1 4.7 4.7 5.0 v3n2 3.1 2.9 4.0 4.4 4.9 4.5 4.5 v3n3 3.1 3.5 3.2 4.2 4.9 4.3 4.2 v3n4 2.9 3.1 3.1 3.9 4.8 4.6 4.6 v4n0 2.6 3.2 2.9 4.2 4.7 3.5 3.4 v4n1 2.8 3.2 2.8 4.2 4.7 5.1 5.3 v4n2 3.3 4.0 3.8 4.3 5.2 4.8 4.7 v4n3 2.3 3.3 3.2 4.3 5.4 4.9 4.0 v4n4 2.5 3.1 2.8 4.5 4.9 4.67 4.5 lsd0.05 0.20 0.22 0.21 0.18 0.23 0.14 0.23 cv (%) 10.1 15.2 16.1 13.2 11.1 10.4 10.2 v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26; n0 = control (no nitrogen), n1 = 80 kg n ha-1 from usg, n2 = 80 kg n ha-1 from prilled urea, n3 = 100 kg n ha-1 from prilled urea and n4= 120 kg n ha-1 from prilled urea dry weight plant-1 was significantly influenced by interaction of variety and n at different das (table 6). results showed that the highest dry weight plant-1 was obtained from v2n1 at 30, 60, 90 das and at harvest (0.64, 7.73, 18.8 and 21.2 g respectively) which was statistically similar with v1n1, v3n1 and v4n1 at 30 das, but at 60, 90 das and at harvest. on the other hand the lowest dry weight plant-1 at 30, 60, 90 das and at harvest was observed as 0.20, 3.88, 8.83 and 10.36 g respectively with v3n0. the highest number of spikelets spike-1 was found the treatment combination of v2n1 and the lowest number of spikelets spike-1 9.27 in v1n0. number of grains spike-1 was significantly influenced by interaction of variety and n, where the highest number of grains spike-1 (46.3) was found the treatment combination of v2n1. on the other hand, the lowest number of grains spike-1 (22.90) was observed in v1n0 . 46 nahal et al. table 6. dry weight plant-1 as influenced by interaction of variety and prilled urea or urea super granules (usg) from november’ 2011 to march’ 2012 interaction (variety x nitrogen) dry weight plant-1 (g) at different days after sowing 30 60 90 at harvest v1n0 0.20 4.1 9.8 11.2 v1n1 0.63 7.3 17.0 20.2 v1n2 0.55 6.5 15.6 16.7 v1n3 0.45 6.4 16.7 19.4 v1n4 0.53 6.2 17.3 18.2 v2n0 0.23 4.4 9.9 10.7 v2n1 0.64 7.7 18.8 21.2 v2n2 0.42 6.4 16.6 18.4 v2n3 0.46 6.9 17.3 19.9 v2n4 0.47 6.8 15.9 20.7 v3n0 0.20 3.8 8.8 10.4 v3n1 0.61 7.3 17.0 19.3 v3n2 0.46 6.2 13.8 16.6 v3n3 0.48 6.2 14.2 17.6 v3n4 0.52 6.1 14.3 19.7 v4n0 0.22 4.1 9.9 10.9 v4n1 0.61 7.2 17.7 20.7 v4n2 0.47 5.6 16.1 18.0 v4n3 0.46 5.7 14.2 17.9 v4n4 0.53 6.4 15.9 17.3 lsd0.05 0.07 0.3 0.5 0.35 cv (%) 10.3 12.8 9.7 10.3 v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26; n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 80 kg n ha-1 from prilled urea, n3 = 100 kg n ha-1 from prilled urea and n4= 120 kg n ha-1 from prilled urea weight of 1000 -grains was significantly influenced by interaction of variety and n (table 7). the highest 1000-grain weight (64.85 g) was found in the treatment combination of v3n1 which was statistically similar to v1n1, v2n1 and v4n1. on the other hand, the lowest 1000grain weight (38.13 g) was observed in v1n0. grain yield was significantly influenced by interaction of variety and n (table 7). results showed that the maximum grain yield (2.80 t ha1) was found in the treatment combination v2n1 which was statistically similar to v4n1 and v2n4 while lower grain yield (1.97 t ha-1) was observed with v3n0 and v4n0 which was statistically similar to v1n0 and v2n0. the maximum straw yield (3.67 t ha-1) was found in v2n3 which was statistically similar to v3n4 and v4n1. on the other hand the lowest straw yield (3.36 t ha-1) was observed in v2n0 which was statistically similar to v2n0 and v4n0the maximum harvest index (45.39%) was found with the treatment combination v2n1 which was statistically similar to v4n1 while lowest harvest index (34.98%) was observed in v3n0 which was statistically similar to v4n0. 47 performance of prilled urea and usg on the growth and yield of wheat table 7. yield and yield contributing parameters and harvest index of wheat as influenced by variety and prilled urea or urea super granules (usg) interaction (variety x nitrogen) number of spikelets spike-1 number of grains spike-1 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) v1n0 9.2 22.90 38.13 2.03 3.52 36.32 v1n1 20.1 43.68 64.75 2.53 3.55 41.88 v1n2 18.2 38.33 53.83 2.47 3.60 40.64 v1n3 17.7 37.68 54.62 2.12 3.57 37.22 v1n4 18.0 38.18 52.07 2.45 3.61 40.42 v2n0 9.4 23.87 48.95 2.02 3.36 36.16 v2n1 22.3 46.34 64.38 2.80 3.56 45.39 v2n2 17.9 36.51 56.11 2.30 3.61 38.94 v2n3 18.0 37.94 59.59 2.37 3.67 39.18 v2n4 18.4 40.66 61.51 2.70 3.42 44.13 v3n0 9.3 24.44 50.87 1.97 3.42 34.98 v3n1 19.0 41.14 64.85 2.63 3.61 43.51 v3n2 16.7 33.42 59.04 2.23 3.54 38.68 v3n3 16.9 34.32 57.64 2.17 3.53 38.05 v3n4 16.7 34.01 60.89 2.38 3.66 39.45 v4n0 9.8 28.24 43.08 1.97 3.39 35.32 v4n1 21.1 45.04 64.66 2.78 3.65 45.07 v4n2 18.2 37.86 58.15 2.63 3.56 42.53 v4n3 17.4 36.18 59.61 2.62 3.53 42.35 v4n4 16.5 34.14 56.06 2.42 3.61 40.13 lsd0.05 0.49 1.040 1.80 0.104 0.05 0.72 cv (%) 8.8 10.16 5.90 11.09 8.51 7.10 v1 = bari gom 21, v2 = bari gom 24, v3 = bari gom 25 and v4 = bari gom 26; n0 = control (no nitrogen), n1 = 84 kg n ha-1 from usg, n2 = 80 kg n ha-1 from prilled urea, n3 = 100 kg n ha-1 from prilled urea and n4= 120 kg n ha-1 from prilled urea conclusion the results of the experiment revealed that the variety bari gom 24 gave the maximum grain yield that was similar to the variety bari gom 26. so, both the varieties may be recommended for wheat cultivation for obtaining the maximum yield. among the different nitrogenous fertilizer, the highest grain yield was obtained from 84 kg n ha-1 from urea super granules (usg). among the interaction effect the combination of 84 kg n ha-1 from usg along with the variety bari gom 24 performed best in case of grain yield that was statistically similar to the variety bari gom 26. therefore, wheat variety bari gom 24 and bari gom 26 could perform better with 84 kg n ha-1 from usg. references akter, h. 2005. yield and seed quality of wheat cultivars as influenced by fertilizer nitrogen level under rainfed and irrigated conditions. m. sc. thesis, dept. of agronomy, bangladesh agril. univ., mymensingh. bbs (bangladesh bureau of statistics). 2008. statistical year book of bangladesh. statistics division, ministry of planning. government of the peoples of bangladesh. 48 nahal et al. donald, c.m. 1963. competition among crop and pasture plants. adv. agron.15:1-118. frg (fertilizer recommendation guide). 2005, bangladesh agricultural research council, farmgate, dhaka-1215. hossain, k. i., c. a. meisner, j, m. duxbury, j. g. lauren, m. m. rahman, m. m. meer and m. h. rashid. 2005. use of raised beds for increasing wheat production in rice-wheat cropping systems. bed planting course, cimmyt. mexico. indian j. agron. 40(4): 51-511. khalil, m. i., u. schmidhalter, r. gutser, and h. heuwinkel. 2011. comparative efficacy of urea fertilization via supergranules versus prills on nitrogen distribution, yield response and nitrogen use efficiency of spring wheat. j. plant nutr. 34(6):779-797. mozumder, a. s. m. m. h. 2001. effect of different seed rates and levels of nitrogen on the performance of shourav variety of wheat m. sc. thesis, dept. of agronomy, banagladesh agril. univ., mymensingh. nadim, m. a., i. u. awan, m. s. baloch, e. a. khan, k. naveed and m. a. khan. 2012. response of wheat (triticum aestivum l.) to different micronutrients and their application methods. j. animal plant sci. 22(1):113-119. onsongo, m. 2003. kenya grain and feed wheat uptake. usda global agriculture information network. gainreport # ke3011. rahman, a.m. 2009. growth and yield components of wheat genotypes exposed to high temperature stress under control environment. bangladesh j. agril. res. 34: 361-372. rahman, m. i. 2005. yield and quality of wheat as influenced by nitrogen sulphr and boron under irrigated and rainfed conditions. m. sc. thesis, dept. of agronomy. bangladesh agril. univ., mymensingh. rahman, m.m., a. hossain, m.a. hakim, m.r. kabir and m.m.r. shah. 2009. performance of wheat genotypes under optimum and late sowing condition. int. j. sustain. crop prod. 4(6): 34-39. saari, f. 1998. leaf blight diseases and associated soil born fungal pathogens of wheat in south and south east asia. cimmyt. pp. 37-51. sarker, m. a. z., m. g. miah, a. hamid, j. haider and a. hashem. 1997. effect of nitrogen level and duration of weed competition on weed biomass, yield and yield attributes of wheat. ann. bangladesh agric. 7(1): 1-7. sikder, s. j. u. ahmed and t. hossain. 2001. heat tolerance and relative yield performance of wheat varieties under late seeded conditions. bangladesh. indian j. agric. res. 35(3): 141-148. singh, g. r. singh and k. purashhttam. 1986. response of wheat (triticum aestivum) to nitrogen, phosphorus and potassium fertilization, indian j. agron. 41(1): 157-159. tariq, m. t. 2010. evaluation of two wheat genotypes performance under drought conditions at different growth stages. department of agronomy, university of agriculture, faisalabad, pakistan. yadav, d. s., r. p. shukla, sushant and b. kumer. 2005. effect of zero tillage and nitrogen level on wheat (triticum aestivum) after rice (oryza sativa). indian j. agron. 50(1): 52-53. bangladesh agron. j. 2017, 20 (1): 77-83 integrated nutrient management on soybean in a coastal charland of bangladesh i. s. m. farhad1*, m. a. rahman2, e. jahan3, m. g. azam4 and n.r.khan5 1 soil science division, bari, gazipur, bangladesh 2department of agronomy, sau, dhaka, bangladesh 3department of agricultural chemistry, sau, dhaka, bangladesh 4rars, bari, hathazari, chittagong, bangladesh 5department of agriculture extension, manikganj, bangladesh *corresponding author, e-mail: farhadsau@gmail.com key words: cost and return, soybean nodulation, yield abstract a field experiment was conducted at char jangalia under mlt site, laxmipur, a coastal district of southern bangladesh, during rabi season of 2015-16 to evaluate the effect of integrated nutrient management on growth and yield performance of soybean (var. glycine max l.). six treatment combinations, viz. t1= control, t2= farmers practice (25-15 kg np ha-1, t3= 100% recommended dose (30-25-55 kg np ha-1, k), t4= 50 % recommended dose + 1.5 t ha-1 vermi compost, t5= 50 % recommended dose + 5 t ha-1compost and t6=50 % recommended dose + 1.2 kg ha-1 bio fertilizer were tested. the experiment was laid out in randomized complete block design with 3 replications. there were significant differences among the different treatment combinations in terms of yield and yield contributing characters. integrated nutrient management with application of 50% of the recommended doses of urea, tsp, mop, and biofertilizer (bradyrhizobium) at the rate of 1.2 kg ha-1 significantly increased most of the parameters, such as the plant height, number of nodule per plant, pods per plant, seeds per pod and seed yield. the highest seed yield (2.93 t ha-1) was recorded from t6 while the lowest seed yield (1.83 t ha-1) was obtained from t1. the highest gross return (tk.117200 ha-1) and gross margin (tk. 71840 ha-1) was obtained from t6, whereas the lowest gross return (tk. 70400 ha-1) and gross margin (tk.27880 ha-1) was obtained from t1. the overall results indicated that the application of integrated nutrient management of a combination of bio fertilizer with 50% n-p-k (1512.5-27.5 kg ha-1) of the recommended dose produced the maximum nodulation and seed yield of soybean in the southern coastal char land. introduction soybean (glycine max l.) is a good source of oil, protein, unsaturated fatty acids, minerals like ca and p including vitamins a, b and d (rahman, 1982). according to kaul and das (1986) it contains 40-45 % protein, 18-20 % edible oil, 24-26 % carbohydrate and a good amount of vitamins moreover, soybean being a leguminous crop has the ability to fix atmospheric nitrogen (n) through root nodule bacteria (bradyrhizobium japonicum) and thus it enriches the soil fertility. soybean is popular and economic mono oil seed crop in laxmipur, a coastal district of southern bangladesh. in laxmipur district, the total soybean cultivation area is about 45 thousands hectares (chowdhury et al., 2013). until recently the cultivation of soybean was 78 farhad et al. concentrated only in greater noakhali area, though the cultivation has been expanded dramatically from only 5000 ha in 2005 (satter et al., 2005) to 61000 ha in the districts of bhola, patuakhali, faridpur, and even in the northern bangladesh (chowdhury et al., 2013). the expansion of cultivation about the high nutrient status of soybean as a human food is increasing in bangladesh (mannan et al., 2012). the average yield of soybean in the world is about 3.0 t ha-1, while in bangladesh it is only 1.2 t ha-1 (saic, 2007). farmers of this coastal area generally grow local variety of soybean without or injudicious application of fertilizer. for this reason, the yield of soybean in this region is much below than that of potential yield level. experimental evidences revealed that the crop was highly responsive to different fertilizers and the yield could be increased remarkably through judicious fertilization (bari, 1988; mohamed, 1984; roy and singh, 1986; kazi et al., 2002). integrated nutrient management practices applied for soybean contributes to sustainable growth of yield and quality, influences soil health and reduces environmental risks. use of organic manures with optimum rate of fertilizers under intensive farming system increased the turnover of nutrients in the soil plant system. the organic manures along with bio fertilizers help in reducing the dose of inorganic fertilizer, which in turn reduces the cost of cultivation and help in improving the soil health. therefore, this study was undertaken to analyze the effect of integrated nutrient management on nodulation, growth and yield of soybean in the southern coastal char land of bangladesh. materials and methods a field experiment was conducted during rabi season of 2015-2016 at char jangalia multilocation trial (mlt) site, laxmipur district of southern coastal bangladesh, which is under young meghna estuarine floodplain called agro ecological zone 18 to evaluate the effect of integrated nutrient management on soybean. before conducting the experiment, initial composite soil samples at 0-15 cm soil depth over 10 spots were collected from the experimental plots and were analyzed in the laboratory following standard methods. the initial soil analysis values are presented in table 1. the experiment was laid out in randomized complete block design with 3 replications. the unit plot size was 4m × 3m. soybean var. bari soybean-5 variety was used as the test crop in this experiment. treatments were : t1 = control, t 2= farmers practice (25-15 kg ha-1 of n-p, survey of 20 farmers), t3= 100% recommended dose (30-25-55 kg ha-1 of n-p-k, frg, 2012), t4 = 50 % recommended dose + 1.5 t ha-1 vermicompost, t5 = 50 % recommended dose + 5 t ha-1compost and t6 = 50 % recommended dose + 1.2 kg ha-1 biofertilizer. seeds were taken in small polythene bags equal in weight for each pot and mixed with molasses @ 20g molasses kg-1seeds. for each inoculation separate plastic bag was used and care was taken to avoid contamination of the inoculated and non-inoculated seeds. then the inoculum (binasb-4) was mixed with the seeds @ 20 g kg-1 seeds for the treatment t6. the seeds were sown @ 60 kg ha-1 on18 january 2016 in line with the spacing of 30 cm x 10 cm. two irrigations were done during the crop duration. first irrigation was applied after 20 to 25 days of sowing before flowering and second irrigation at pod formation stage. different intercultural operations and plant protection measures were taken as and when necessary to raise healthy crops. the crop was harvested on 20 april, 2016. three (03) plants were randomly selected from each plot and carefully 79 integrated nutrient management on soybean in a coastal charland of bangladesh uprooted to study the nodule number. soil from the root was removed carefully and the nodules were separated and counted at 30 das, 60 das and at harvest. data were collected on an individual plant basis from ten (10) randomly selected plants of each plot in such a way that the border effect was avoided for high precision. plant height and number of branches plant-1were recorded during harvest. number of pods plant-1, number of seeds pod-1 and 100seed weight were recorded after harvesting of the crop. plot yield was recorded and then converted to t ha-1. analysis of variance and comparison of means were calculated separately with statistical package mstat-c programme (gomez and gomez, 1984). the means were compared using the least significance difference (lsd) test. the functional form of the linear relationship between a dependent variable y and an independent variable x was calculated according to equation given by gomez and gomez, (1984). x represents the amount of change in y for each unit change in x. table 1. chemical properties of initial soil (0 -15 cm depth) of the experimental field at char jangalia, mlt site, laxmipur during rabi season of 2015-16 sample ph ec oc om total n k ca mg p s zn b ds m-1 (%) (%) (%) meq/100 g soil µg g-1 soil average 6.7 1.58 0.9 1.54 0.08 0.11 5.0 2.3 9 46 1.95 0.66 critical level 0.12 0.12 2.0 0.5 10 10 0.6 0.2 interpretation neutral non saline low low very low low optimum very high low very high high high ec = electrical conductivity, oc = organic carbon, om = organic matter results and discussions the soil of the experimental site was neutral in reaction having ph 6.7 and non-saline (table 1). the organic matter was low (1.5%) and total n content was very low (0.08%). available k and p were below the critical level but available s, ca, mg, zn and b were exist in satisfactory level. number of nodules plant-1 the inoculation of bradyrhizobium and chemical fertilization had a significant effect on total number of nodules plant-1 at different days after sowing (table 2). results indicated that the highest number of nodules plant-1 was observed in the treatment t6 (76.3) at 60 days after sowing which was significantly different from other treatments. the lowest number of nodule plant-1 (21.3) was recorded from control treatment (t1). the results further revealed that integrated use of bradyrhizobium and 50% chemical fertilizers (n-p-k) substantially increased the nodules number compared to other treatments. . the nodule number of plant was gradually decreased after 60 das till harvesting in all the treatments. the lowest number of nodule was recorded at harvesting stage in all the treatments, presumably due to root senescence during ripening stage of the crop. the reason of the maximum nodulation in inoculated plants was probably due to the fact that bradyrhizobium aids in nodulation. these results comply with that of egamberdiyeva et al. (2004) who observed significantly higher number of nodules produced in inoculated plants compared with uninoculated one. 80 farhad et al. table 2. effect of integrated nutrient management on nodules per plant at different days after sowing (das) of soybean var. bari soybean-5 at char jangalia, laxmipur during 2015-16 treatments number of nodules per plant 30 das 60 das at harvesting stage t1 = control 6.5 21.3 1.4 t2 = farmers practice (25-15 kg ha-1 of n-p) 8.1 32.5 2.5 t3 = 100% recommended dose 11.2 41.1 2.7 t4 = 50 % recommended dose + 1.5 t ha-1 vermicompost 14.5 59.8 4.1 t5 = 50 % recommended dose + 5 t ha-1 compost 14.2 54.2 3.5 t6 = 50 % recommended dose + 1.2 kg ha-1 biofertilizer 23.7 76.3 5.2 lsd (0.05) 2.28 6.96 1.20 cv (%) 9.8 8.2 11.2 recommended dose: 30-25-55 kg ha-1 of n-p-k according to frg, 2012 growth, yield and yield contributing characters plant height of soybean responded significantly to the integrated use of bio fertilizer (bradyrhizobium) and chemical fertilizers, n-p-k (table 3). the maximum plant height was observed in the treatment t6 (67.2 cm) followed by the treatment t4 (64.4 cm) and the lowest in the control treatment (48.3 cm). the result was similar to the findings of singh and rai (2005) who observed that the integrated use of chemical fertilizers and bio-fertilizer increased plant height significantly in soybean. the maximum number of branches plant-1 (3.3) was observed in t6 treatment which was statistically identical with t4 and t5 treatment, whereas the lowest number of branches plant-1 (2.2) in t1 (control) treatment. pods plant-1 and seeds pod-1 was significantly influenced by the integrated use of bradyrhizobium with 50% of the recommended dose of chemical fertilizers (table 3). maximum number of pods plant-1 (48.4) and seeds pod-1 (2.25) was recorded in the treatment t6 followed by the treatment t4. the minimum pods plant-1 (34.3) and seeds pod-1 (1.93) was in t1. the result related to pods plant-1 was similar to the finding of tomar et al.(2004), who observed that soybean plants treated with bradyrhizobium inoculants significantly increased the number of pods plant-1. on the other hand, seeds pod-1 was similar to the study of jain and trivedi ( 2005) who reported that the soybean plants treated with bradyrhizobium alone or in combination with different levels of chemical fertilizers gave highest number of seeds pod-1. the maximum pod length (3.33cm) was observed in t6 treatment which was statistically significant with all other treatments. the maximum 100seed weight (12.4g) was recorded in t6 treatment which was statistically at par with t3, t4 and t5 treatments, while the lowest 100 seed weight (11.7g) was in t1 treatment. seed yield was significantly influenced by the integrated use of bradyrhizobium with or without organic and inorganic fertilizers. the seed yield varied from 1.83 to 2.93 t ha-1 in the different 81 integrated nutrient management on soybean in a coastal charland of bangladesh treatments. the maximum seed yield (2.93 t ha-1) was observed by the application of bradyrhizobium with 50% of the recommended dose of chemical fertilizers (n-p-k) followed by the treatment t4 (2.78 t ha-1). the lowest seed yield (1.83 t ha-1) was recorded in the uninoculated treatment (control plot). table 3. effect of integrated nutrient management on yield and yield contributing characters of soybean var. bari soybean-5 at char jangalia, laxmipur during 2015-16 treatments plant height (cm) branches plant-1 (no.) pods plant-1 (no.) pod length (cm) seeds pod-1 (no.) 100seeds weight (g) seed yield (t ha-1) t1 48.3 d 2.2 d 34.3 d 3.06 c 1.93 c 11.7 b 1.76e t2 54.5 c 2.5 c 37.6 c 3.10 c 1.98 c 11.8 b 2.15 d t3 59.1 b 2.9 b 44.5 b 3.11 c 2.11 b 12.2 a 2.57 c t4 64.4 a 3.1 a 47.1 ab 3.18 b 2.18 ab 12.3 a 2.78 b t5 63.7 a 3.1 a 45.7 b 3.18 b 2.16 ab 12.2 a 2.71 bc t6 67.2 a 3.3 a 48.4 a 3.33 a 2.25 a 12.4 a 2.93 a lsd (0.05) 3.54 0.21 2.53 0.05 0.109 0.37 0.14 cv (%) 4.48 5.27 6.43 2.40 5.87 1.79 7.25 t1 = control, t2 = farmers practice, t3 = 100% rec. dose (frg, 2012), t4 = 50 % rec. dose + 1.5 t ha-1 vermicompost, t5 = 50 % rec. dose + 5 t ha-1 compost, t6 = 50 % rec. dose + 1.2 kg ha1biofertilizer from the simple regression (table 4) it was found that the regression co-efficients for plant height, branches plant-1, pods plant-1, pod length, seeds pod-1 and 100seeds weight were positively significant with yield indicating that increase in the values of these characters would increase the yield of the crop. in case of plant height, if 1.0 unit of plant height were increased then yield would be increased by 0.06 unit. similarly, in case of branches plant-1, pods plant-1, pod length, seeds pod-1 and 100 seeds weight yield would be increased by 1.05 units, 0.078 unit, 2.80 units, 3.54 units and 1.54 units, respectively. table 4. simple regression between yield and yield contributing characters plant characters intercept (a) slope (b) plant height -1.2038 0.0619** branches plant-1 -0.523 1.0549** pods plant-1 -0.854 0.0777** pod length -9.5495 2.8079* seeds pod-1 -4.9438 3.5339** 100 seeds weight -16.09 1.535** *= significant at 5% level **= significant at 1% level cost and return analysis from the cost and return analysis, the maximum gross return and gross margin tk.117200 ha-1 and tk.71840ha-1 , respectively were recorded from the treatment t6 which was 50 % recommended dose (n-p-k) + 1.2 kg ha-1biofertilizer. the lowest gross return and gross margin of tk.70400 ha-1 and tk.27880 ha-1, respectively were obtained from the control treatment (table 5). 82 farhad et al. table 5. cost and return analysis of bari soybean-5 as influenced by integrated nutrient management at char jangalia, laxmipur during 2015-16 treatments gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) t1 70400 42520 27880 t2 86000 45926 40074 t3 102800 47960 54840 t4 111200 65740 45460 t5 108400 63240 45160 t6 117200 45360 71840 input and output price per kg: soybean seed = tk. 60, urea = tk. 16, tsp = tk. 22, mop = tk. 15, vermicompost = tk. 15, compost = tk. 4, bio-fertilizer = tk.100 and soybean = tk. 40. conclusion based on the results, it may be concluded that integrated nutrient management of bio-fertilizer (bradyrhizobium) along with 50% of the recommended dose of chemical fertilizers (n-p-k) was more effective than other fertilizer management packages in producing seed yield and economic return of soybean cultivation in the char areas under young meghna estuarine floodplain soil (aez 18f) of bangladesh. references bangladesh agricultural research council (barc). 2012. fertilizer recommendation guide. new airport road, farmgate, dhaka.pp.85-96. bangladesh agriculture research institute (bari). 2006. krishi projukti hatboi (in bangla). 4th ed., bangladesh agricultural researchinstitute, gazipur, bangladesh. pp. 209-211. chowdhury, m. m. u., m. j. u. sarker., a.k. choudhury.,i.s.m. farhad., s.k. bhowal, and k. m. f. hossain. 2013. soybean cultivation in coastal area of noakhali. on-farm research division, bangladesh agricultural research institute, gazipur, bangladesh. p.1. egamberdiyeva, d., d. qarshieva and k. davranov. 2004. the use of bradyrhizobiumto enhance growth and yield of soybean in calcareous soil in uzbekistan. j. plant growth regul.23: 5457. gomez, a. k. and a. a. gomez. 1984. statistical procedure for agricultural research. international rice research institute. john willy and sons., singapore.p. 680. hoque, m.s. and m.a. hashem. 1994. field evalution of some promising bradyrhizobium inoculants on soybean and groundnut at different locations. bangladesh agricultural university, research program, 8: 118-122. jain, p.c. and s.k. trivedi. 2005. response of soybean (glycine max l. merrill) to phosphorus and biofertilizers. legume res. 28 : 30-33. kaul, a. k. and m. l. das. 1986. oilseeds in bangladesh. bangladesh canada agriculture sector team, ministry of agriculture, government of the people’s republic of bangladesh, dhaka, p. 324. file:///f:/review/4723-17157-1-pb.pdf%23page=1 file:///f:/review/4723-17157-1-pb.pdf%23page=1 83 integrated nutrient management on soybean in a coastal charland of bangladesh kazi, b. r., f.c. oad and a. lakho. 2002. effect of irrigation frequencies on growth and yield of soybean. pakistan j. appl sci., 2: 661-662. mannan, m. a., m. a. karim, m. m. haque, q. a. khaliq, h. higuchi and e. nawata. 2012. response of soybean to salinity: i. genotypic varistions in salt tolernce at the vegetative stage. trop. agr. develop. 56: 117-122. mohamed, s.a. 1984. effect of irrigation water and fertilization on yield and water use efficiency of corn plants in fayoum governorate, moshtohor, egypt. ann. agril. sci 20:221-235. rahman, l. 1982. cultivation of soybean and its uses. city press, dhaka. pp. 5-7. roy, r. k. and k. s. p. singh.2005. response of popcorn (zea mays) to plant population and nitrogen. indian j. of agron.31: 87-92. saic. 2007. saarc agricultural statistics of 2006-07. saarc agricultural information centre, farmgate, dhaka-1215. p. 23. satter, m.a., m. rahman and m.s. alam. 2005. krishi projucti hatboi. bangladesh agricultural research institute, gazipur1701, bangladesh, p. 155. singh, r. and r.k. rai. 2005. yield attributes, yield and quality of soybean as influenced by integrated nutrient management. indian j. agron. 49: 271-274. tomar, s.s., r. singh and p.s. singh. 2004. response of phosphorus, sulphur and rhizobium inoculation on growth, yield and quality of soybean (glycine max l.). progress in agril. sci. 4: 72-73. bangladesh agron. j. 2018, 21(2): 7-11 suitabilityof different winter vegetables with sweet gourd s.s. kakon1*, j.a. chowdhury1, m.m. bazzaz2, m.m. alam3 , a.a. begum 1, m. a. aziz1 1agronomy division, bangladesh agricultural research institute, joydebpur gazipur 1701, bangladesh 2 agricultural research station, rajbari, dinajpur 3regional agricultural research station, hathazari, chittagong *corresponding author, e-mail: kakonbari@gmail.com (received: 14 september 2017, accepted: 11 april 2019) abstract the experiment was conducted at joydebpur and rajbari farm of bangladesh agricultural research institute during two successive rabi seasons (2014-16) to find out the suitable vegetable for intercropping with sweet gourd for higher productivity and economic return. six intercrop combinations of sweet gourd and vegetables viz., t1 = sole sweet gourd, t2 = sweet gourd (2 m x 2 m) + cabbage (50 cm x 50 cm), t3 = sweet gourd (2m x 2m) + cauliflower (50 cm x 50 cm), t4 = sweet gourd (2 m x 2 m) + radish (20 cm x 25 cm), t5 = sweet gourd (2 m x 2 m) + lettuce (50 cm x 50 cm), t6 = sweet gourd (2 m x 2 m) + tomato (50 cm x 50 cm) were tested at joydebpur and rajbari. the highest mean sweet gourd yield (31.37 t ha-1 at joydebpur and 34.54 t ha-1 at rajbari) was recorded in sole sweet gourd over the years. the highest mean vegetable yield (42.87 t ha-1 at joydebpur and 61.40 t ha-1 at rajbari) was recorded in sweet gourd + cabbage combination. maximum mean sweet gourd equivalent (sey) yield (72.55 t ha-1), highest gross return (tk. 362775 ha-1 and bcr (2.98) were recorded in sweet gourd + cabbage combination over the years at joydebpur. the maximum mean sey (79.38 t ha-1), highest gross return (tk. 396905 ha-1) and bcr (3.25) were recorded in sweet gourd + cauliflower combination at rajbari. two year results revealed that sweet gourd + cabbage and cauliflower might be suitable intercrop combination for getting maximum yield and economic return. introduction bangladesh is a small country but food demand is high due to high rate of population growth. in order to produce more food within a limited area, one of the most important options is to increase the cropping intensity producing two or more crops over the same piece of land. vegetables are the main component of human food that supplies proteins, carbohydrates, fats, vitamins and minerals. our vegetable production is much less than the requirement. however, limited scope of bringing additional land for vegetable production, demands intervention of growing more vegetables per unit area and time i.e., intercropping. while intercropping is widely practiced with cereals, the benefits of intercropping vegetables both from our economic and dietary aspects have been largely ignored. intercropping of legume vegetables with other vegetables may increase vegetable consumption and develop soil fertility through symbiotic nitrogen fixation (willey, 1979) intercropping is one of the cropping strategies that have been recognized to improve the food security situation and incomes for the farmers (mahfuza, 2012). about:blank 8 kakon et al. intercropping also helps to reduce weed populations, insect pest infestation and risk of complete crop failure (amede, 2001; islam et al., 2013). intercropping system becomes more productive and profitable when it is done properly by selecting compatible crops (begum et al., 2010) and increasing vegetable productivity (rashid, 1987). sweet gourd is an important vegetable sown with wide spacing, and may be grown in both rabi and kharif season. different winter vegetables (cabbage, cauliflower, radish, lettuce and tomato) may be grown in association with sweet gourd. however, some farmers of panchagar and khulna districts have been practicing sweet gourd intercropping with tomato and cauliflower instead of sole cropping. different farmers use different winter vegetables for intercropping with sweet gourd. this experiment was conducted to select suitable vegetables for intercropping with sweet gourd. materials and methods the experiment was conducted at the research field of agronomy division, bari, joydebpur, gazipur and ars, rajbari during rabi seasons of 2014-15 and 201516. six intercrop combinations of sweet gourd and winter vegetables viz., t1= sole sweet gourd, t2= sweet gourd (2m x 2m) + cabbage (50 cm x 50 cm), t3 = sweet gourd (2m x 2m) + cauliflower (50 cm x 50 cm), t4 = sweet gourd (2m x 2m) + radish (20 cm x 25 cm), t5 = sweet gourd (2m x 2m) + lettuce (50 cm x 50 cm), t6 = sweet gourd (2m x 2m) + tomato (50 cm x 50 cm) were tested the experiment was laid out in a rcb design with 3 replications. the unit plot size was 4 m x 4 m. sweet gourd var. bari misti kumra-2, cabbage var. bari badhacopy-1, cauliflower var. bari fulcopy-1, tomato var. bari tomato-2, lettuce var. bari lettuce-1 and radish var. bari mula-1 were used. seeds of radish were sown on 25 november at joydebpur and twenty five days old seedlings of cabbage, cauliflower, lettuce and tomato were transplanted on the same day in both the years. on the other hand, at rajbari, seeds of radish were sown on 25 november 2014 and 09 november 2015 and twenty five days old seedlings of cabbage, cauliflower, lettuce and tomato were transplanted on the same day in both the years. thirty days old seedlings of sweet gourd were transplanted on 12 december 2014 and 19 november 2015. thirty days old seedlings of sweet gourd were transplanted on 10 december in both the years at joydebpur and different winter vegetables were planted in line according to the treatments at 15 days before transplanting of sweet gourd seedlings. fertilizers @ 80-36-100-24-2-2 kg ha-1 npksznb + cd: 10 t ha-1 were applied in sole sweet gourd chemical fertilizers were used in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid. fertilizers @ 100-50.5-90.5-18-2.3 kg ha-1 npksznb + cd: 10 t ha-1 were applied in vegetables. organic manure and chemical fertilizers were applied at the final land preparation, while urea and mop were top dressed in two equal splits at 15 and 35 dat of winter vegetables. all chemical fertilizer along with organic manure was applied in pit 7 days before transplanting of winter vegetables and sweet gourd seedlings. at joydebpur sweet gourd harvesting was started from 93 dat and four harvesting was done up to 1 -5 april 2015 and 2016. cabbage and cauliflower was harvested two times (55 and 70 dat). lettuce was harvested at 35 dat and tomato was harvested four times at 85, 90, 93 and 100 dat in both the years. on the other hand, at rajbari, sweet gourd harvesting was started from 105 dat and harvesting was done four times. cauliflower was harvested three times (59, 68 and 74 dat). lettuce was harvested at 45 and 55 dat and tomato was harvested five times at 91, 98, 105, 112, 119, and 126 dat in both the years. intercultural operations like watering, weeding and pest control suitability of different winter vegetables with sweet gourd were done as and when required. yields of both the crops were taken from whole plot. collected data of all crops were analyzed statistically and the means were adjudged using lsd test at 5% level. benefitcost analysis was also done. sweet gourd equivalent yield was computed using the formula of bandyopadhaya (1984). sweet gourd equivalent yield (sey) (kg ha-1) = sg p .p.yi vegveg yisg + where, yi sg = sweet gourd yield (kg ha-1) in intercropping. yiv eg. = veg. yield (kg ha-1) in intercropping psg = price of sweet gourd (kg ha-1) pveg. = price of vegetable (kg ha-1) results and discussion yield and yield component of sweet gourd number of fruits plant-1 and fruit yield of sweet gourd were significantly affected by the treatments (table 1) in both the years. the maximum number of fruits/plant (8.83 in 2014-15 and 6.57 in 2015-16 at joydebpur and 6.3 in 2014-15 and 3.33 in 2015-16 at rajbari) were obtained from sole sweet gourd treatment but at par to other treatment except t6 which produced lowest fruits plant-1. similar trend was followed in case of single fruit weight. the maximum fruit yield (35.89 and 26.84 t ha-1 at joydebpur and 33.87 and 35.21 t ha-1 at rajbari) were obtained from sole sweet gourd and the lowest (16.33 and 19.71 t ha-1 at joydebpur and 7.64 and 8.01 t ha-1 at rajbari) in sweet gourd + tomato in 2014-15 and 2015-16, respectively. at joydebpur, sweet gourd yield was lower in 2015-16 than 1st year due to heavy rainfall at flowering stage which produced lower photosynthetic rate caused lower yield. the higher yield in sole crop might be due to the utilization of wider space and less competition for natural resources. ali et al. (2003) also reported similar result. among the intercropped treatments, t5 treatment (sweet gourd + lettuce) produced higher fruit yield (35.54, 25.73 t ha-1 at joydebpur) might be due to early harvesting of lettuce and less competition of different growth resources. on the other hand, at rajbari t4 treatment produced slightly higher fruit yield (29.63 and 31.82 t ha -1) of sweet gourd in both the years. in pooled analysis, friut yield showed maximum in sole situation (table 2) table 1. fruit yield and yield components of sweet gourd in sole intercropping system in rabi seasons of 2014-15 and 2015-16 at joydebpur and rajbari vegetables fruits plant-1 (no.) single fruit wt. (kg) fruit yield (t ha-1) joydebpur rajbari joydebpur rajbari joydebpur rajbari 201415 201516 201415 201516 201415 201516 201415 201516 201415 201516 201415 201516 t1 8.83 6.57 6.3 3.33 1.95 1.84 2.02 4.30 35.89 26.84 33.87 35.21 t2 8.33 6.37 5.7 1.96 1.94 1.75 1.89 3.22 34.62 24.76 17.02 15.77 t3 8.20 6.24 5.9 2.30 1.81 1.75 1.97 4.20 33.04 21.84 20.96 22.01 t4 8.53 6.51 5.7 3.00 1.91 1.79 1.99 4.24 34.35 24.50 29.63 31.82 t5 8.63 6.40 5.5 2.95 1.87 1.81 1.87 3.18 35.54 25.73 29.47 24.37 t6 5.57 3.83 3.6 1.75 1.35 1.57 1.51 3.12 16.33 19.71 7.64 8.01 lsd(0.05) 1.56 1.10 1.33 0.71 0.19 0.141 0.17 0.64 3.41 3.23 3.67 3.37 cv (%) 8.9 10.06 4.44 8.02 5.79 4.26 6.07 9.05 5.93 7.42 8.80 8.10 8 kakon et al. t1 = sweet gourd (2 m x 2 m), t2 = sweet gourd (2 m x 2 m) + cabbage (50 cm x 50 cm), t3 = sweet gourd (2 m x 2 m) + cauliflower (50 cm x 50 cm), t4 = sweet gourd (2 m x 2 m) + radish (20 cm x 10 cm), t5 = sweet gourd (2 m x 2 m) + lettuce (50 cm x 50 cm), t6 = sweet gourd (2 m x 2 m) + tomato (50 cm x 50 cm) winter vegetables the highest cabbage yield (38.32 and 47.42 t ha-1 at joydebpur and 58.31 and 64.49 t ha-1 at rajbari) was recorded in sweet gourd + cabbage combination and the lowest yield (10.59 and 10.84 t ha-1 at joydebpur) in t5 treatment in both the years. whereas, at rajbari, the lowest lettuce yield 12.49 and 13.21 t ha-1 were recorded from sweet gourd + lettuce and sweet gourd + radish combination in 2014-15 and 2015-16, respectively. intercrop efficiency sweet gourd equivalent yield and benefit cost analysis of sole and intercropping are presented in table 3. sweet gourd equivalent yields (sey) in all intercropping systems were higher than sole sweet gourd (35.89 t ha-1) indicating higher productivity of intercropping systems. similar results were mentioned by alom et al. (2013). among the intercropping systems, maximum sey was 72.55 t ha-1 was recorded in sweet gourd + cabbage combination which was followed by sweet gourd + cauliflower combination (69.99 t ha-1) at joydebpur. higher sey in these combinations might be contributed by combined effect of both the components. maximum gross return (tk. 362775 ha-1) was recorded in sweet gourd + cabbage combination which was close to sweet gourd + cauliflower combination. this treatment showed the highest bcr (2.98) which was also close to sweet gourd + radish combination (2.90) at joydebpur. this result is in agreement with the finding of islam et al. (2013). at rajbari, the highest sey (79.38 t ha-1) and gross return (tk. 396905 ha-1) was recorded in sweet gourd + cauliflower combination which was close to sweet gourd + cabbage combination. this treatment showed the highest mean bcr (3.25). table 2. yield of different winter vegetables with sweet gourd (mean), sweet gourd equivalent yield (sey) and cost and return analysis (average of two years) at joydebpur and rajbari treatment fruit yield (t ha-1) vegetable (t ha-1) sey (t ha-1) cost of cultivation (tk ha-1) gross return (tk ha-1) bcr joy. raj. joy. raj. joy. raj. joy. raj. joy. raj. joy. raj. t1 31. 37 34. 54 31. 37 34. 54 112 500 110 000 156 825 172 700 1.41 1.57 t2 29. 69 16. 40 42. 87 61. 40 72. 55 77. 80 121 700 120 700 362 775 388 975 2.98 3.22 t3 27. 44 21. 49 21. 28 36. 19 69. 99 79. 38 122 000 122 000 349 950 396 905 2.84 3.25 t4 29. 43 30. 73 38. 76 19. 82 68. 18 62. 43 123 315 117 500 340 900 312 145 2.90 2.66 t5 30. 64 26. 42 10. 72 14. 38 56. 36 49. 43 115 825 115 000 281 775 247 140 2.44 2.15 t6 18. 02 7.8 3 35. 05 40. 62 66. 65 48. 44 126 105 125 000 333 250 242 200 2.65 1.94 t1 = sole sweet gourd t2 = sweet gourd (2 m x 2 m) + cabbage (50 cm x 50 cm), t3 = sweet gourd (2 m x 2 m) + cauliflower (50 cm x 50 cm), t4 = sweet gourd (2 m x 2 m) + radish (20 cm x 10 cm), t5 = sweet gourd (2 m x 2 m) + lettuce (50 cm x 50 cm), t6 = sweet gourd (2 m x 2 m) + tomato (50 cm x 50 cm), sey= sweet gourd equivalent yield market price (tk kg-1): sweet gourd5/-, cabbage5/-, cauliflower10/-, radish10/-, lettuce12/and tomato5/at joydebpur, sweet gourd-5/-, cabbage5/-, cauliflower8/-, radish8/-, lettuce -8/and tomato5/at rajbari suitability of different winter vegetables with sweet gourd conclusion the overall results indicated that among the intercrop combinations sweet gourd (2 m x 2 m) + cabbage / cauliflower (50 cm x 50 cm) combination was found suitable for total productivity and economic return at rajbari but at joydebpur sweet gourd (2 m x 2 m) + cabbage / raddish was found viable.. references ali, m. y., m. s. islam, a. k. m. m. rahman, m. m. hossain and m. m. haque. 2003. economic performance of tomato intercropping with vegetables. bangladesh j. agril. res. 28(4): 619-623. alom, m. s., b. l. nag, m. n. islam, f. ahmed and s. akther 2013. performance of different crop species with pointed gourd (trichosanthes dioica roxb.) bangladesh j. agril. res. 38(3): 523-529. amede, t. and y. nigatu. 2001. interaction of components of sweetpotato-maize intercropping under the semi-arid conditions of the rift-valley, ethiopia. tropical agriculture. 78(1): 1-7. begum, s., m. n. islam, m. t. rahman, j. a. chowdhury. and m. i. haque. 2010. suitability study of different chili varieties for intercropping with sweet gourd. j. exp. biosci. 1(2): 1-4. bandyopadhyay, s. n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. islam, m. n., m. s. rahman, f. ahmed, m. s. alom and m. akhteruzzaman. 2013. performance of different hyv mustard varieties with sugarcane (sacchaarum officinarum) as intercrop in farmers’ fields. bangladesh j. agril. res. 38(1): 137-143. mahfuza, s. n., m. n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping of different vegetables and spices with pointed gourd. j. exp. biosci. 3(1):77-82. rashid, m. a. 1987. effect of intercropping cabbage and batisak at varying plant population levels. m.sc. (ag.) thesis, department of horticulture, bau, mymensingh. bangladesh agron. j. 2015, 18(2): 23-29 performance of hybrid maize varieties as influenced by irrigation levels m. s. bhuiyan1, m. s. r. bhuiyan2, t. p. tiwari3, m. a. rahaman4 s. k. bhowal5, r. uddin6 and s. k. paul1 1agronomy division, bari, gazipur, bangladesh 2department of genetics and plant breeding, sau, dhaka, bangladesh 3cimmyt-bangladesh, dhaka, bangladesh 4ofrd, bari, tangail, bangladesh; 5ofrd, bari, comilla, bangladesh 6rars, bari, barisal, bangladesh corresponding author’s: sawkatsarfuddin@gmail.com key words: hybrid maize, irrigation levels, water saving abstract the present piece of research work was carried out at the field of sher-e-bangla agricultural university, dhaka-1207, from december 2010 to may 2011 to determine optimum irrigation levels for the hybrid maize varieties. there were four hybrid maize varieties: v1 (bari hybrid maize-5), v2 (pacific 60), v3 (nk 40) and v4 (ajanta) and three levels of irrigation: i1 = two irrigations at 25 and 50 das, i2 = three irrigations at 25, 50 and 75 das and i3 = four irrigations at 25, 50, 75 and 100 das, respectively. almost all the plant and yield contributing characters showed significant variation except days to 6 leaf stage and days to bud initiation stage. the maximum yields were recorded in v1i3 (7.92 t ha-1) which was statistically identical to v4i3 (7.83 t ha-1), v2i3 (7.45 t ha-1), v1i2 (7.40 t ha-1), v2i2 (6.87 t ha-1) and v4i2 (6.80 t ha-1), respectively. the highest benefit cost ratio (bcr) was observed (2.37) in both v1i3 and v1i2 treatment combination. moreover, total average water saving in one hectare land for maize cultivation by adopting i2 irrigation treatment over i3 is 4,49,837 gallons. among the treatment combinations, v1i3 (bari hybrid maize-5 with three irrigations at 25, 50 and 75 das) was the suitable combination in terms of grain yield and economic return for maize cultivation. introduction maize (zea mays l.) is considered as the third cereal crop in bangladesh after rice and wheat. its position is the first among the cereals in terms of yield, but area and production ranks third after rice and wheat. it covers about 4,09,000 acres of land producing 10,18,000 tons of grains in 2010-11 (bbs, 2011) in bangladesh. hybrid maize cultivation area has increased at the rate of about 20-25% per year since nineties. now-a-days, there are many government and non government organizations are working for increasing maize production in bangladesh. besides, bangladesh agricultural research institute (bari) has released eleven promising hybrid maize varieties. variety plays an important role in producing high yield and good quality maize. different varieties respond differently to input supply, cultivation practices and prevailing environment etc. during the growing season. higher yield up to 9-11 t ha-1 can be obtained using hybrid seeds, balanced fertilizers and better management practices (mondal et al., 2014). the average yield of maize in bangladesh is rather low compared with leading maize growing countries of the world. availability as well as the cost of management of irrigation water is one of the most expensive inputs for maize cultivation. moreover, at present, the farmers are facing the problem of getting available irrigation water and may be acute in future because of the lowering water table day by day. proper growth and development of maize needs 24 bhuiyan et al. favorable soil moisture up to its root zone. limited water supply during the growing season results in soil and plant water deficits and reduces maize yields (gordon, et al., 1995; patel et al., 2006). irrigation scheduling is necessary for the most effective use of valuable water for optimizing maize production. proper water management reduces irrigation cost. so,for proper growth and development of hybrid maize, appropriate irrigation scheduling is needed (lafound et al., 1992; arshad et al., 1995). improper scheduling of irrigation results not only in wastage of water but decrease the crop growth and in yield. in these circumstances, a research work was undertaken to find out the suitable maize hybrid variety (s) with lower water requirement and to find out the best irrigation management practices for higher economic return. materials and methods the study was conducted at the experimental farm of sher-e-bangla agricultural university, dhaka-1207, during december 2010 to may 2011. the location of the experimental site was situated at 230 77' n latitude and 900 3' e longitudes with an elevation of 8.6 meter from the sea level. the experimental site wassituated in the subtropical zone. the soil of the experimental site belongs to madhupur tract of agro ecological zone (aez-28) (fao, 1988). the soil was clay loam in texture and olive gray with common fine to medium distinct dark yellowish brown mottles. the ph was 5.47 to 5.63. the organic matter and k content of the soil is low but status of cec and p is medium (barc, 2005). the experiment was set up in a split plot design with three replications where variety (v1= bari hybrid maize-5, v2= pacific-60, v3= nk-40 and v4= ajanta) in main plot and irrigation level (i1 =two irrigations at 25 and 50 das, i2 = three irrigations at 25, 50 and 75 das and i3 = four irrigations at 25, 50, 75 and 100 das, respectively) in sub-plot. irrigation have been applied to reach the soil moisture upto field capacity so no infiltrations have been occurred. the dosages of fertilizer (512-275-200-222-14-6 kg/ha urea-tsp-mop-gypsum-znso4-boric acid) were applied according to frg, 2005, barc. seeds were sown by hand at 75 cm apart line to line and 25 cm plant to plant. post sowing light irrigation was given for proper germination of seeds. two weedings were done at 24 and 49 days after sowing (das) and two thinning were done also at 24 and 49 das, keeping one plant per hill. the mixture of diazinon 60 ec @ 2 ml/l and ripcord 10 ec @ 1 ml/l of water was applied to control leaf cutting caterpillar at 6-8 leaf stage for two times, seven days interval. the water requirement for maize cultivation is determined by measuring the soil moisture. the depth or water requirement can be determined by the following equation irrigation depth, fc (%) mci (%) d = -------------------------x ρ x d ---------------------------(1) 100 where, d= depth of water to be applied (cm), fc= field capacity of the soil (%), mci= moisture content of the soil at the time of irrigation (%), ρ = bulk density of the soil (gm / cc), d= root zone depth (cm) the collected data were statistically analyzed using mstat-c statistical programme with least significant difference (lsd) by gomez and gomez (1984). results and discussion interaction effects of variety and irrigation levels on plant characters of hybrid maize 25 performance of hybrid maize varieties as influenced by irrigation levels interaction effect of variety and irrigation levels varied significantly except days to 6 leaf stage and days to bud initiation stage (table 1). all the combinations took 44-46 days to open the first 6 –leaf stage. the maximum days (82) were needed in v4i1 in 12 leaf stage and while other combination took almost similar days (76-77). the variation on days to bud initiation was insignificant while days to tassel emergence t range maximum and minimum days (87 and 83). days to tassel flowering were observed in different treatment combination from 86 to 89 days. silk emerged just after the tassel flowering which also varied significantly, while the maximum days (90) in v2i3, v3i1 and v3i3 and the minimum days (88). days to pollen shedding were statistically significant where v3i3 needed the maximum day (92) while the minimum days (89) in v1i3. nizam-uddin et al., (2010) and malik et al., (2010) supported the above findings and stated that; cultivars differed significantly for all parameters. interaction effects of variety and irrigation levels on yield and yield contributing characters of hybrid maize interaction effect of different variety and irrigation levels treatment on yield and yield contributing characters of hybrid maize shown in table 2. plant height increases with increase the number of irrigation among all the varieties. cob height showed almost the same trend of result found from the plant height. the nearest cob (66 cm) from the ground was found from v3i1 and the farthest cob (97 cm) in v1i3. the longest distance (85 cm) was found in v1i2 followed by v4i3 (83cm) and v1i3 (81 cm) whereas the shortest in v4i1 (60 cm) followed by v3i1 (61 cm) and v1i1 (64 cm). number of cobs increased with the application of irrigation water. among the variety, the maximum number of cobs (1.2) were found in v2 and v4 followed by v1 (1.17) in i3 irrigation treatment. the highest cob length (16.7 cm) was found from v1i3 while the lowest cob length (13.3 cm) from v2i1 and v4i1. the grain weight per cob in the treatment combination v4i2, v1i2 and v2i2, were 142, 141 and 139, respectively followed by v3i3 (140 g). 1000-grains weight increased with the number of application of irrigation water. however, the maximum 1000-grain weight was recorded in the treatment combination v3i3 which was statistically identical with v3i2 v4i3 v4i2 and v1i3. the grain yield of different treatment combination varied significantly where the highest grain yields was obtained in four irrigation (i3) and the lowest in two irrigation (i1) in all the variety. a gradual increasing trend was observed in every variety with the increase of irrigation level. therefore, it is evident that, irrigation has a great effect on hybrid maize yield regardless of variety. among the treatment combination, variety v3 with all the irrigation levels gave the lowest yield, even its highest yield (6.22 t ha-1) in i3 was statistically at par with the i2 irrigation level of other varieties. the lowest yields (4.89, 5.01, 5.53 and 5.65 t ha1 , respectively) were recorded with i1 irrigation level in v3, v4, v1, and v2 , respectively. the yield increased in v1 from i1 to i2 was 34% and i2 to i3 7%, in v2 from i1 to i2 was 21% and i2 to i3 8%, in v3 from i1 to i2 was 24% and i2 to i3 2% and in v4 from i1 to i2 was 35% and i2 to i3 15%, respectively. it was also observed that, incase of v1 the yield in i2 was better than the yield of other varieties in i2 irrigation. aziz et al., (2011) observed that, among the varieties bari hybrid maize-5 produced maximum grain yield. islam and mian (2004) showed that, varieties had significant variation on yield and yield contributing characters. biological yield of different treatment combination also varied significantly. the highest biological yield was obtained from v1i3 while lowest from v1i1. irrigation water utilization and economic analysis of different treatment combinations the average irrigation water used in i1 was 1209725 gallons ha-1 with the average grain yield of 5.27 t/ha whereas in i3, 2079587 gallons ha-1 with the grain yield of 7.36 t ha-1. in i2, moderate yield of 6.79 t ha-1 was observed with 1629750 gallons ha-1 irrigation water which 26 bhuiyan et al. was statistically identical to i3. moreover, 4, 49,837 gallons of water can be saved by using i2 irrigation treatment without reducing significant quantity of grain yield. among the varieties v1 gave the highest yield (7.40 t ha-1) with i2 treatment therefore, the treatment combination of v1i2 gave higher yield with moderate level of irrigation water (table 3). in i3 irrigation treatment higher amount water was used but yield was not statistically different from i2. total average water saving in one hectare of land for maize cultivation by adopting i2 irrigation treatment over i3 irrigation treatment was (20,79,587 – 16,29,750) = 4,49,837 gallons. therefore, i2 irrigation treatment was optimum irrigation practices for maize cultivation considering yields and water saving aspect. cost benefit analysis effect of variety and irrigation combination on cost and economic benefit of the hybrid maize production has shown in table 4. the highest total variable cost (tk. 69028/ha) was observed in the i3 treatment and the lowest total variable cost (tk. 59028/ha) in i1 treatment with all the varieties. the increment of cost (tk. 4500/ha) and (tk. 5500/ha) was found in i2 from i1 and i3 from i2, respectively. the highest human labor cost (tk. 10500/ha) was found in i3 irrigation treatment followed by i2 (tk. 10000/ha) and i1 (tk. 9500/ha), respectively. one time higher irrigation level increased the cost tk. 1000 ha. the highest irrigation cost (tk. 17000/ha) was observed in the i3 treatment whereas the lowest irrigation cost (tk. 10000/ha) was observed in i1 treatment. the highest gross return (tk. 163870/ha) was found in v1i3 treatment combination which was similar to v4i3 (tk.161115/ha) and the lowest gross return (tk. 100710/ha) was in v3i1. the highest net return (tk. 94842/ha) was found in v1i3 t which was followed by v4i3 (tk. 92087/ha) treatment combination. the lowest net return was found in v3i1 (tk. 41682/ha). the highest benefit cost ratio (bcr) 2.37 was observed in v1i2 and v1i3 treatment combination with three and four irrigations. the lowest bcr (1.71) was observed in v3i1 treatment combination followed by v4i1 (1.74) and v1i1 (1.90), respectively. therefore, it was observed that i2 irrigation treatment produced almost similar returns and benefit cost ratio with i3 irrigation level. moreover, a huge quantity of irrigation water can be saved by utilizing i2 instead of i3 irrigation level. so, i2 irrigation treatment was the most effective treatment because yields and yield contributing characters of maize were very much similar with i3 irrigation treatment. in i1 irrigation treatment maize yields was lower with lower yield contributing characters. two, three and four irrigation increased yields by an additional 16.9, 6.7 and 4.3% respectively. water savings can be achieved by applying two or three irrigations which should increase yield without significantly reducing yield compared to four irrigations. pandey et al. (2000) observed that yield reduction (22.6 26.4%) were found with deficit irrigation and this was associated with decrease in kernel number and weight. karim et al., (2010) found that the coefficient of human labour, land preparation, irrigation, urea and borax have significantly impact on gross return. table 1. interaction effect of variety and irrigation on different plant characters of hybrid maize treatment combination days to 6 leaf days to 12 leaf days to bud initiation days to tassel emergenc days to tassel flowering days to silk emergenc days to pollen shedding 27 performance of hybrid maize varieties as influenced by irrigation levels e e v1i1 44 78 83 83 87 89 90 v1i2 45 76 82 85 88 89 90 v1i3 47 78 84 86 87 88 89 v2i1 44 77 82 84 87 89 90 v2i2 45 78 85 87 88 89 91 v2i3 46 76 82 86 88 90 90 v3i1 44 78 84 85 89 90 90 v3i2 46 79 84 86 87 89 90 v3i3 45 78 85 87 89 90 92 v4i1 45 82 83 83 87 89 90 v4i2 46 79 81 84 86 88 90 v4i3 47 77 82 85 87 89 90 lsd (0.05) ns 3.96 ns 2.78 2.11 1.97 1.46 cv (%) 2.70 3.00 2.57 1.93 1.43 1.30 0.96 table 2. interaction effect of variety and irrigation on yield and yield contributing characters of hybrid maize treatment combination plant height (cm) cob height (cm) cob length (cm) grain weight / cob (g) 1000grain weight (g) grain yield (t/ha) biologica l yield (t/ha) v1i1 142 77 13.7 116 268 5.53 9.02 v1i2 170 84 15.0 131 290 6.60 12.14 v1i3 178 97 16.7 156 318 8.44 18.86 v2i1 149 81 13.3 119 297 5.95 10.00 v2i2 163 89 13.7 139 303 6.87 11.23 v2i3 170 92 15.3 145 309 7.94 15.22 v3i1 127 66 13.7 103 284 4.89 10.71 v3i2 156 80 15.0 127 339 6.11 13.20 v3i3 163 91 15.3 140 340 6.63 16.53 v4i1 141 82 13.3 102 270 5.01 10.98 v4i2 159 91 14.7 142 319 6.8 13.99 v4i3 179 96 15.7 150 335 8.35 16.86 lsd (0.05) 10.3 7.43 0.60 10.8 19.9 0.74 1.72 cv (%) 7.76 10.3 4.83 9.76 7.69 13.40 15.30 v1= bari hybrid maize-5, v2= pacific-60, v3= nk-40 and v4= ajanta i1 =two irrigations at 25 and 50 das, i2 = three irrigations at 25, 50 and 75 das and i3 = four irrigations at 25, 50, 75 and 100 das table 3. total average irrigation water applied in different treatment combination maize yield treatment combination total average water used (cm) total irrigation water used (gallons/ha) grain yield (t/ha) 28 bhuiyan et al. i1v1 45.8 1213700 5.53 i1v2 46.3 1226950 5.65 i1v3 46.3 1226950 4.89 i1v4 44.2 1171300 5.01 i2v1 61.5 1629750 7.40 i2v2 61.4 1627100 6.87 i2v3 62.6 1658900 6.11 i2v4 60.5 1603250 6.80 i3v1 80.9 2143850 7.92 i3v2 78.4 2090850 7.45 i3v3 76.7 2032550 6.22 i3v4 77.4 2051100 7.83 v1= bari hybrid maize-5, v2= pacific-60, v3= nk-40 and v4= ajanta i1 =two irrigations at 25 and 50 das, i2 = three irrigations at 25, 50 and 75 das and i3 = four irrigations at 25, 50, 75 and 100 das table 4. effect of variety and irrigation on cost and economic benefit treatment combinationcost items v1i1 v1i2 v1i3 v2i1 v2i2 v2i3 v3i1 v3i2 v3i3 v4i1 v4i2 v4i3 h. labors (tk./ha)* 9500 10000 10500 9500 10000 10500 9500 10000 10500 9500 10000 10500 fuel (tk./ha) 3000 4000 5000 3000 4000 5000 3000 4000 5000 3000 4000 5000 manure (tk./ha) 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 10000 urea (tk./ha) 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 tsp (tk./ha) 9612 9612 9612 9612 9612 9612 9612 9612 9612 9612 9612 9612 mp (tk./ha) 10656 10656 10656 10656 10656 10656 10656 10656 10656 10656 10656 10656 gypsum (tk./ha) 660 660 660 660 660 660 660 660 660 660 660 660 boric acid (tk./ha) 600 600 600 600 600 600 600 600 600 600 600 600 irrigation (tk./ha) 10000 13000 17000 10000 13000 17000 10000 13000 17000 10000 13000 17000 seeds (tk./ha) 3000 3000 3000 3000 3000 3000 3000 3000 3000 3000 3000 3000 tvc (tk./ha)# 59028 63528 69028 59028 63528 69028 59028 63528 69028 59028 63528 69028 gross return (tk./ha) 112345 150370 163870 115175 139580 152885 100710 125690 129555 103185 139595 161115 net return (tk./ha) 53317 86842 94842 56147 76052 83857 41682 62162 60527 44154 76067 92087 benefit cost ratio 1.90 2.37 2.37 1.95 2.19 2.21 1.71 1.98 1.88 1.74 2.19 2.33 a) maize =20.00 tk./kg b) labor = 250 tk./day *h. labors= human labors, #tvc=total variable cost conclusion from the above findings, it may be concluded that, all the selected hybrid maize varieties viz., bari hybrid maize-5, pacific-60 and ajanta except nk-40 gave higher benefits in three irrigation levels at 25 , 50 and 75 days after seeding (das). but it may be noted that, maize 29 performance of hybrid maize varieties as influenced by irrigation levels variety (bari hybrid maize-5 with three irrigation levels at 25, 50 and 75 das was the best in terms of grain yield and return among all the treatment combination. references arshad, m. a., gill, k. s. and s. coy. 1995. barley, canola, and weed growth with decreasing tillage in a cold, semiarid climate. agron. j. 87: 4-55. aziz, m. a., a. k. m. m. rahman, r. chakma, m. ahmed and a. f. m. s. ahsan. 2011. performance of bari hybrid maize varieties in the hilly areas of bangladesh. j. expt. biosci. 2(2): 25-28. barc (bangladesh agricultural research council). 2005. fertilizer recommendation guide, 2005. bangladesh agril. res. council, farmgate, new airport road, dhaka. p. 15. bbs (bangladesh bureau of statistics). 2011. statistcal yearbook of bangladesh, statistics division, ministry of planning, govt. peoples repub. bangladesh. p. 207. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. a wiley int. sci. publ. john wiley and sons. new york, brisbane, singapore. pp. 139-240. gordon, w. b., r. j. raney and l. r. stone. 1995. irrigation management practice for corn production in north central kansas. j. soil water conserve. 50(4): 395-398. islam, a. k. m. a. and m. a. k. mian. 2004. comparative performance of ten hybrid maize (zea mays l.). bangladesh j. plant. breed. genet. 17(2): 09-14. karim, m. r., m. moniruzzaman and q. m. alam. (2010). economics of hybrid maize production in some selected areas of bangladesh. bangladesh j. agril. res. 35(1): 83-93. lafoud, g. p., h. loeppky and d. a. derksen. 1992. the effect of tillage systems and crop rotations on soil water conservation, seedling establishment and crop yield. can. j. plant sci. 72: 103-115. malik, h. n, i. ara, m. naeem, m. hussain, m. h. munawwar and m. yousaf. 2010. comparison of open pollinated varieties and newly developed hybrids for yield and yield contributing traits in maize. pakistan j. agril. res. 23(1/2): 37-41. mondal, m. r. i., m. k. sultan, s. nur, m. j. u. sarkar, m. s. alam and m. h. h. rahman. 2014. krishi projukti hatboi (handbook on agro-technology), 6 th edition. bangladesh agricultural research institute, gazipur 1701, bangladesh. nizamuddin, m. qasimand m. hussain. 2010. comparative study of agronomic parameters in synthetic maize varieties. j. agril. res., lahore. 48(1): 53-57. patel, j. b., v. j. patel and j. r. patel. 2006. influence of different methods of irrigation and nitrogen levels on crop growth rate and yield of maize (zea mays l.). ind. j. crop sci., 1(1-2): 175-177. microsoft word 6. baj-225_revised.docx bangladesh agron. j. 2016, 19(1): 45-48 hybrid maize and chilli intercropping in the hilly areas of bandarban m. ahmed1, s. ishtiaque1*, m. m. r. sarker1, a s m m r khan1, a. k. choudhury1, m. k. hasan1 f. hossain1, s. k. paul2 and m. u. islam3 1 on-farm research division, bangladesh agricultural research institute (bari), gazipur-1701 2 agronomy division, bangladesh agricultural research institute (bari), gazipur-1701 3 oil seed research center, bangladesh agricultural research institute (bari), gazipur-1701 *corresponding author: sheikh11ishtiaque@gmail.com keywords: intercropping, hill farming, multiple cropping, yield abstract the experiment was conducted at farmers’ field of on-farm research division (ofrd), bandarban during rabi season of 2014-15 to find out suitable combination of hybrid maize and chilli intercropping system to increase system productivity and economic return. the experimental design was randomized complete block (rcb) design with six dispersed replications. the maize var. bari hybrid maize-9 and chilli (local) were used in the experiment. two intercropping combinations viz., maize single row (100 cm x 25 cm) + 2 rows chilli (50 cm x 40 cm) and maize single row (150 cm x 25 cm) + 3 rows chilli (50 cm x 40 cm) were evaluated against their sole crops. the highest gross return (tk. 435040 ha-1), net return (tk. 366290 ha-1) and benefit cost ratio (6.33) were recorded in maize single row (150 cm x 25cm) + 3 rows chilli (50 cm x 40 cm) combination. cob yield of hybrid maize and green fruit yield of chilli were the highest in the respective sole crops. the results revealed that maize single row (150 cm x 25 cm) + 3 rows chilli (50 cm x 40 cm) combination might be suitable and economically profitable for the hilly areas. introduction intercropping is a traditional practice in bangladesh. maize (zea mays), the third most important cereal crop of the world, is an important dual purpose crop used in human diet and animal feed. maize has the potential to supply large amounts of energy-rich forage for animal diets, and its fodder can safely be fed at all stages of growth. the cultivation of two or more crop species simultaneously in the same field during a growing season is known as intercropping (ofori and stern, 1987). it has many advantages over sole cropping which provides an efficient utilization of environmental resources, reduces risk to the cost of production, provides greater financial stability for farmers, decreases pest damages, suppresses weeds growth more than monocultures, improves soil fertility through nitrogen increasing to the system and improves forage yield and quality (francis et al., 1976). intercropping is a crop management system involving the growing of two or more dissimilar crops in distinct row combinations simultaneously on the same land area. intercropping involves crop intensification in respect to both time and space dimensions (ahlawat and sharma, 2002). chilli is one of the major spices crop in bangladesh cultivated in 2, 40,000 acres of land (both winter and summer) with a production of 1, 26, 000 metric ton (bbs, 2012). the review of research work done so far indicated that growth of chilli as intercrops is more beneficial than growing chilli in many situations (aravazhi et al., 1997; natara jan, 1992; sadashiv, 2004). intercropping increases total productivity through efficient growth resources. inter-specific competition may be minimized through judicious choice of crops (santalla et. al., 2001). several short duration and short stature crop like chilli may be grown 46 ahmed et al. in association with hybrid maize. incident light may be increased on below storey crop by changing planting geometry of hybrid maize. this experiment was conducted to find out suitable planting systems of hybrid maize and chilli intercropping system for higher productivity and economic return. materials and methods the experiment was conducted at hilly areas of bandarban during rabi season of 2014-15. the hybrid maize (var. bari hybrid maize 9) and chilli local were used in this intercropping experiment. the treatment combinations were t1= sole maize (60 cm x 20 cm), t2= sole chilli (50 cm x 40 cm), t3= single row maize (150 cm x 25 cm) + 3 rows chilli (50 cm x 40 cm) and t4= single row maize (100 cm x 25 cm) + 2 rows chilli (50 cm x 40cm). the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 4 m x 3 m. seeds of maize and chilli were sown on november 25-30, 2014. sole hybrid maize was fertilized with 250-55-l10-40-4-2 kg ha-1 n p k s zn b, while sole chilli was grown with 120-80 -120-20-4 kg ha-1 n p k s zn and intercrop was grown with 370-55-110-40-4-2 kg, n-p-k-s-zn-b ha-1, respectively. for sole maize the full amount of p k s zn b and 1/2 n were applied as basal in the form of triple super phosphate, muriate of potash, gypsum, zinc sulphate, boric acid and urea, respectively. the remaining n was top dressed at 30 days after sowing (das). chilli, 1/2 n and all other fertilizers were applied as basal. the rest amount of n was top dressed in three splits at 25, 50 and 70 dat. on the other hand in case of intercrop l/3 n and all other fertilizers were applied as basal. the rest amount of n was top dressed in three splits at 25, 50 and 70 dat. irrigation was given after sowing / planting for proper establishment of crops. subsequently three irrigations were applied at 30, 60 and 90 dat. two hand weedings were done at 20 and 40 dat to keep the crops reasonably weed free. green cob of maize was harvested at 135 and 142 das (5 and 12 april, 2015) and chilli was harvested at 112, 130 and l52 dat. maize equivalent yield was calculated by converting the yield of intercrops to the yield of maize on the basis of prevailing market prices of individual crops. economic analysis on the basis of net monetary return was performed to evaluate the intercropping system. maize equivalent yield was calculated as: maize equivalent yield (mey) = (tk./kg) maizeof price )(tk./ha intercropof ×price ha) (kg/ intercropof yield  the gross return, cost of cultivation, gross margin, and net return was computed from different treatments on the basis of prevailing market price of maize grain, groundnut pod and both the crop-straw and biomass. benefit cost ratio (bcr) of different treatments was computed as follows: bcr = (tk./ha) productionof cost total (tk./ha) retrungross data of both the crops were analyzed statistically and the means were adjudged by using lsd test. results and discussion effect on maize: plant population, cob weight with husk, yield of green cob with husk, green fodder yield and grain yields per hectare of hybrid maize were influenced significantly due to intercropping with chilli under different planting systems (table 1). weight of single cob was more in sole maize (387 g). among intercrop treatments, maximum single cob weight was recorded in t4 (312 g). the highest cob yield was found in sole maize (17.58 t ha-1). among 47 hybrid maize and chilli intercropping in the hilly areas of bandarban intercrop treatments, the highest cob yield was obtained from t4 (14.25 t ha-1). the lowest cob yield was recorded in t3 (12.64 t ha-1) due to mainly for minimum number of cobs / plot. similar to green cob yield, the highest green fodder yield was recorded in sole maize (36.57 t ha-1). in intercrop situation, higher green fodder yield was obtained from t4 (29.53 t ha-1). highest grain yield was found 9.63 t ha-1 in case of sole maize cultivation. effect on chilli: fruit yield and other yield attributes of chili were significantly affected by the maize + chili intercropping systems (table 2). the highest number of fruits / plant was obtained from the treatment t4 (312). the lowest number of fruits / plant was obtained from t2 (283). the maximum fruit weight/plant was obtained from the treatment t4 (472.58 g) and the lowest from t2 (392.37 g). significantly the highest fruit yield (9.52 t ha-1) was observed in t2 while the lowest from t4 (5.43 t ha-1). variation in fruit yield ha-1 of chilli might be influenced by the plant population in the intercropping systems. fruit yield increased with the increase of plant population. intercrop efficiency: green cob yield, fodder yield, green chilli yield and economic study of hybrid maize + chilli intercropping system are presented in table 1, 2 & 3. total yield in terms of cob yield (12.64 t ha-1), fodder yield (26.64 t ha-1), and green chilli yield (7.96 t ha-1) were lower than sole maize or sole chilli. among intercropping systems, higher cob yield, fodder yield was obtained from t4 due to higher cob yield (14.25 t ha-1) but in case of green chilli yield 5.43 t ha-1 which is lower than other intercrops. so, among intercropping systems t3 combination is more suitable than others due to higher gross return (tk. 435040 ha-1), net return (tk. 366290 ha-1) and benefit cost ratio (6.33) as compared to other combination. table 1. yield and yield components of hybrid maize in maize +chilli intercropping under different planting systems treatment plants m-2 (no.) cob weight with husk (g) yield of green cob with husk (t ha-1) green fodder yield (t ha-1) grain yield (t ha-1) t1 6.67 387 17.58 36.57 9.63 t3 2.67 285 12.64 26.64 6.48 t4 4.00 312 14.25 29.53 7.56 lsd (0.05) 2.48 2.89 0.97 0.94 2.02 cv (%) 5.76 8.53 4.57 5.78 7.94 table 2. yield and yield components of chilli in maize + chilli intercropping system treatment plants m-2 (no.) fruit plant-1 (no.) fruit weight plant-1 (g) fruit yield (t ha-1) t2 4.38 283 392.37 9.52 t3 3.27 296 425.14 7.96 t4 2.68 312 472.58 5.43 lsd (0.05) 3.48 12.57 14.67 2.44 cv (%) 6.81 5.64 7.61 5.14 table 3. benefit cost ratio analysis of maize-chilli intercropping under different planting systems 48 ahmed et al. treatment mey % increased mey over sole maize maize grain yield (t ha-1) chilli fruit yield (t ha-1) gross return (tk. ha-1) total cost of production (tk. ha-1) gross margin (tk. ha-1) bcr t1 9.63 9.63 173340 66750 106590 2.60 t2 21.16 (+)120 9.52 380800 63750 317050 5.97 t3 24.17 (+)151 6.48 7.96 435040 68750 366290 6.33 t4 19.63 (+)104 7.56 5.43 353280 68750 284530 5.14 meg : maize equivalant yield t1 : sole maize (60 cm x 20 cm), t2 : sole chilli (50 cm x 40 cm), t3: single row maize (150 cm x 25cm) + 3 rows chilli (50 cm x 40 cm), t4: single row maize (100 cm x 25 cm) + 2 rows chilli (50 cm x 40 cm) local market price (tk. kg-1): maize grain =18/-, chilli= 40/ conclusion the result revealed that single row maize (150 cm x 25cm) + 3 rows chilli (50cm x 40cm) combination had higher equivalent yield and economic return than sole crop of maize and chilli. so, this combination might be suitable for improving crop productivity and economic return in the hilly areas. references ahlawat, i. p. s. and r. p. sharma. 2002. agronomic terminology. indian society of agronomy, division of agronomy, indian agricultural research institute, new delhi, india. aravazhi e., s. natarajan and s. thambaraj. 1997. economics of intercropping in chilli. south indian hort. 45: 139-194. bbs (bangladesh bureau of statistics). 2012. agricultural statistical yearbook of bangladesh, 2014. francis, c. a., c. a. flor and s. r. temple. 1976. adapting varieties for intercropping systems in the tropics. in: papendick r. i., p. a. sanches and g. b. triplett. (eds.). multiple cropping. special publication number 27. pp. 235-253. madison. american society of agronomy. natarajan, s. 1992. effect of intercrops on chilli (capsicum annum l.) under semi dry conditions. south indian hort. 40: 273-276. ofori, f. and w. r. stern. 1987. cereal-legume intercropping systems. adv. agron. 41: 41-90. sadashiv, b. 2004. production potential of hybrid cotton (gossypium hirsutum) based vegetable intercropping systems under irrigation. m.s thesis, university of agricultural sciences, dharwad, india. santalla, m., a. p. rodino, p. a. casquero and a. m. de ron (2001). interactions of bush bean intercropping with field and sweet maize. european j. agron.15: 185-196. introduction bangladesh agron. j. 2015, 18(1): 59-63 evaluation of n efficiency using prilled urea and urea super granules in t. aman rice j hussain1, m salim2, *m a siddique3, m khatun4 and s islam5 1harvestplus-bangladesh, barisal; 2department of agronomy, bangladesh agricultural university, mymensingh 3genetic resources and seed division, bangladesh rice research institute, gazipur 4janata bank limited, barisal; 5bangladesh agricultural development corporation, mymensingh *corresponding author: mabs198401@yahoo.com key words: nitrogen use efficiency, prilled urea, urea super granule, transplant aman rice abstract an experiment was conducted at the experimental field of department of agronomy, bangladesh agricultural university, mymensingh, during june to december 2007 to evaluate the nitrogen use efficiency of transplant aman rice using prilled urea (pu) and urea super granule (usg). three rice varieties (br11, brri dhan30 and brri dhan39) were compared at three doses of nitrogen, i.e., pu@125 kg n ha-1, usg @170 kg n ha-1 and usg @ 70 kg n ha-1 in a randomized complete block (rcb) design with three replications. usg each weighing 1 g and 2.6 g were placed manually at the depth of 8-10 cm in the middle of four hills in alternate rows at 12 days after transplanting and pu applied in split applications. the rice var. br11 at usg @70 kg n ha-1 has produced the maximum grain yield (4.75 t ha-1) which was statistically identical to brri dhan30 at usg @ 70 kg n ha-1 (1 g pellet-1). the highest nitrogen use efficiency, partial factor productivity and marginal rate of return (1966%) were recorded from the treatment of br11 at usg @ 70 kg n ha-1. introduction farmers of bangladesh generally apply nitrogenous fertilizers in several split applications and the efficiency of applied nitrogen uptake by the rice plant ranges between 25 and 35% (singh and yadav, 1985). the applied nitrogen is lost due to leaching, surface run-off, nh3 volatilization, denitrification and other processes; consequently n fertilizer use efficiency decreases. there are different types of nitrogenous fertilizers available in bangladesh. urea super granules (usg) are one of them and urea super granule that can be applied to the root zone of the rice plants at 8-10 cm depth of soil (reduced zone of rice soil), which can save 30% nitrogen compared to prilled urea. it increases absorption rate, improves soil health and ultimately increases rice yield (savant et al., 1991). deep placement of usg effectively increases n use efficiency (31.7%) compared to conventionally applied prilled urea (jaiswal and singh, 2001). therefore, it is essential to evaluate the response of high yielding rice varieties such as to different levels of urea super granules. materials and methods the experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh during aman season, 2007. the three high yielding rice varieties namely, br11 (v1), brri dhan30 (v2), brri dhan39 (v3) and three sources of nitrogen namely prilled urea at the rate of 125 kg n ha-1 (n1), one pellet of usg (weight 2.6 g) per 4 hills 170 kg n ha-1 (n2), one pellet of usg (weight 1 g) per 4 hills 70 kg n ha-1 (n3) were 60 hussain et al. laid out in a factorial randomized complete block design (rcbd) with three replicates. the unit plot size was 10 m2 (4.0 m x 2.5 m). at the time of final land preparation, 51.25 kg triple super phosphate (tsp), 60 kg muriate of potash (mp), 33.75 kg gypsum and 5 kg zinc sulphate ha-1 were applied. nitrogen was applied according to the treatments. thirtydayold seedlings were transplanted at the rate of 3 seedlings hill-1 on the well-puddled plots on 13th august 2007 maintaining 25 cm x 15 cm spacing. after 12 days of transplanting, one pellet of different sizes (2.6 g and 1 g) usg as a source of nitrogen were placed manually in the root zone at 8-10 cm depth at the centre of four hills of two adjacent rows. appropriate plant protection measures and management practices were followed throughout the growing period.. the grain yield was adjusted to 14% moisture content. the agronomic efficiency of nitrogen (aen) was calculated as additional grain yield over the control per kilogram n applied with the following formula: aen (kg grain kg-1 n applied) = plot fertilized n in napplicatio fertilizer nof quantity plot control in yieldgrain -plot fertilized n in yieldgrain the partial factor productivity of nitrogen (pfp-n) was calculated with the following formula: pfp-n = )ha (kg n appliedof amount )ha (kg yieldgrain total 1-1 marginal rate of return (mrr) was calculated for the treatment xi as marginal gross margin of xi marginal cost that vary of xi data were analyzed and were separated according to duncan’s multiple range test (dmrt). results and discussion interaction between variety and nitrogen level was significant for number of tiller, panicle, grains per panicle and sterile spikelets per panicle. there was no significant difference in plant height (table 1). the results are in agreement with the findings of rahman (2003) who observed that different levels of usg did not affect the plant height. the variety br11 grown with 70 kg n ha-1 as usg produced the highest number of tillers/ sq. meter (408.8) and the lowest from brri dhan39 with pu (table 1). the higher number of tillers resulted at 70 kg n ha-1 as usg might be due to increased availability of nitrogen that played a vital role in cell division. the results differ with the findings of hasan (2007) who recorded the increased number of tiller/sq.m with the increased n level as usg. table 1. effect of interaction between variety and source of nitrogen on crop characters of t. aman rice. variety x nitrogen plant height (cm) tillers no./sq.meter panicle no./sq. meter v1n1 97.03 347.47b 230.93c v1n2 95.86 288.00d 152.27d v1n3 99.66 408.8a 304.8a v2n1 97.30 284.27d 172.27d v2n2 95.60 336.00bc 236.27c v2n3 97.80 360.8b 284.27b v3n1 101.23 270.13d 163.47d v3n2 99.66 321.6c 197.33cd v3n3 102.23 344.00b 228.27c cv (%) 2.58 6.85 4.60 in a column, figures with same letter or without letter do not differ significantly as per dmrt v1 = br11, v2 = brri dhan30, v3 = brri dhan39,n1 = 125 kg n ha-1 (pu/no pellet of usg), n2 = usg (170 kg n ha-1), n3 = usg (70 kg n ha-1) mrr= 61 evaluation of n efficiency using prilled urea and urea super granules in t.aman rice interaction between variety and nitrogen was found significant in panicles/ sq.meter where the highest number of panicle/sq.meter (304.8) was from br11 at 70 kg n ha-1 as usg while lowest panicles (152.27) was produced by same variety at 170 kg n ha-1 as usg. application of n fertilizers significantly increased the number of grains per panicle where variety br11 at 70 kg n ha-1 as usg produced highest number of grains per panicle (148.9) while lowest number of grains per panicle (101.95) from the brri dhan30 at pu. availability of more nitrogen from usg during grain formation and development that contributed to higher number of grains per panicle. these results are in agreement with the findings of thakur (1991). the interaction between variety and dose of nitrogen on number of sterile spikelets per panicle was significant where brri dhan39 produced the highest number of sterile spikelets per panicle (35.90) when n was applied in the form of prilled urea while the variety brri dhan30 at 70 kg n ha-1 as usg produced the lowest number of sterile spikelets per panicle (14.3). application of nitrogen had no significant effect on the 1000-grain weight (table 2). the results are in agreement with the findings of hasan (2007) who also observed that the different levels of usg did not affect the 1000-grain weight. grain yield was not significantly influenced by the interaction between variety and nitrogen dose but maximum grain yield (4.75 t ha-1) was recorded in br11 with usg @ 70 kg n ha-1 and the lowest (3.25 t ha-1) in brri dhan30 with pu. it was also noted that all the rice varieties responded in the same way to the different nitrogen doses. similar trend was followed in case of straw yield and harvest index. harvest index ranged from 44.07 to 48.39% (table 2). table 2. effect of interaction between variety and nitrogen source on yield contributing characters and yield of t. aman rice. variety x nitrogen grains panicle-1 (no.) sterile spikelets panicle-1 (no.) 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) v1n1 140.91b 23.78bc 24.82 3.58 4.16 46.26 v1n2 126.55c 25.77b 24.52 3.83 4.83 44.23 v1n3 148.89a 21.00c 24.98 4.75 5.08 48.39 v2n1 101.95e 15.39d 21.39 3.25 4.08 44.28 v2n2 114.77d 21.10c 21.91 3.33 4.25 44.07 v2n3 132.06c 14.33d 22.29 4.08 4.83 45.84 v3n1 130.17c 35.90a 24.07 3.41 3.91 46.62 v3n2 142.21ab 27.20b 24.37 3.5 4.33 44.58 v3n3 147.64ab 23.88bc 24.35 3.91 4.58 46.18 cv (%) 3.21 8.37 1.14 6.94 8.36 5.07 in a column, figures with same letter or without letter do not differ significantly as per dmrt. two n use efficiency indicators were used i.e. agronomic efficiency of n (aen) and partial factor productivity of n (pfp-n). from table 3, it was evident that when n was applied as usg at 170 kg n ha-1, grain yield was less and agronomic efficiency of n (aen) was found minimum (1.47, 0.47 and 0.52 kg grain / kg n respectively) for all varieties while when n was applied at 70 kg n ha-1 as usg 62 hussain et al. aen were found maximum (16.71, 11.86 and 7.14 kg grain/kg n, with all varieties (br11, brri dhan30 and brri dhan39 respectively). the results are in agreement with the findings of siddika (2007) who observed that, n use efficiency was higher with usg as compared to prilled urea. table 3. effect of n (pu, usg) on grain yield, aen, and pfpn management techniques treatments applied n as urea (kg ha-1) grain yield ( t ha-1) agronomic efficiency of n (aen) partial factor productivity of n (pfp-n) v1n1 125 3.58 00 28.64 v1n2 170 3.83 1.47 22.53 v1n3 70 4.75 16.71 67.86 v2n1 125 3.25 0 26.0 v2n2 170 3.33 0.47 19.59 v2n3 70 4.08 11.86 58.29 v3n1 125 3.41 00 27.28 v3n2 170 3.50 0.52 20.59 v3n3 70 3.91 7.14 55.86 it was also observed that when n was applied as usg at 170 kg n ha-1 poor performance in respect of partial factor productivity of n (pfp-n) were 22.53, 19.59 and 20.59, with rice varieties br11, brri dhan30 and brri dhan39 respectively. however, with the use of usg at 70 kg n ha-1 pfp-n was recorded to be highest in all varieties (67.86, 58.29 and 55.86 respectively). the prilled urea performed the lowest in respect of pfp-n. dominance analysis: six treatments v3n3, v2n3, v3n1, v2n1, v3n2 and v1n2 were found cost dominated, where cost is more but gross margin is less than that of many other treatments (table 4) table 4. dominance analysis gross margin treatment variable cost (tk.ha-1) cost dominance 68253 v3n3 2127 * 71313 v2n3 2127 * 83373 v1n3 2127 58125 v3n1 3255 * 55245 v2n1 3255 * 61185 v1n1 3255 57835 v3n2 5165 * 54775 v2n2 5165 * 63775 v1n2 5165 marginal analysis: the marginal analysis of undominated cost of treatments is shown in table 5. the treatment v1n3 showed the highest mrr (1966%) indicating that the fertilizer 70 kg n ( usg) dose if applied in br11 production during t. aman season gives the highest marginal rate of return. 63 evaluation of n efficiency using prilled urea and urea super granules in t.aman rice table 5. marginal analysis of undominated fertilizer response data gross margin treatment variable cost (tk.ha-1) marginal cost (tk.ha-1) marginal gross margin (tk.ha-1) marginal rate of return (mrr) (%) 83373 v1n3 2126 1128.4 22188.4 1966 61185 v1n1 3255 1909.6 2590.4 136 63775 v1n2 5164 0 0 0 according to the results of the present study maximum utilization of n is possible with the application of proper dose of n as usg. if the dose of n as usg is higher, yield is reduced. it can be concluded that, usg at 70 kg n ha-1 can be used to achieve better nitrogen use efficiency and higher yields than pu with high yielding rice varieties. conclusion from all treatment combinations it is clear that usg @ 70 kg n ha-1 produced more grain yield compared with usg @170 kg n ha-1 and prilled urea. nitrogen use efficiency, partial factor productivity and marginal rate of return to capital were highest at usg @ 70 kg n ha-1 compared to usg @ 170 kg n ha-1 and prilled urea. so, the present n fertilizer recommendation of usg would be 70 kg n ha-1 to optimize yield, rate of return and n use efficiency of rice varieties br11, brri dhan30 and brri dhan39. references hasan, s.m. 2007. effect of level of urea supergranules on the performance of t. aman rice. m. sc. ag. thesis in agronomy, bau, mymensingh. jaiswal, v.p. and g.r. singh. 2001. performance of urea supergranule and prilled urea under different planting methods in irrigated rice (oryza sativa). indian j. of agric. sci. 71 (3):187-189. rahman, m.a. 2003. effect of levels of urea supergranules and depth of placement on the growth and yield of transplant aman rice. ms (ag.) thesis, dept. agron., bangladesh agril, univ., mymensingh. 100 p. savant, n.k., s.s. dhane and s.c. talashikar. 1991. fertilizer news. intl. fert. dev. centre. muscle, shoals, alabama, usa. 36(3): 19-25. siddika, n. 2007. effect of nitrogen management with prilled urea, urea supergranule and leaf color chart on the performance of transplant aman rice (cv., brri dhan41). m.s. ag. thesis in agronomy, bau, mymensingh. singh, m. and d.s. yadav. 1985. nitrogen use efficiency in rice. fert. newsl. 32: 1723. thakur, r.b. 1991. relative efficiency of prilled urea and modified urea fertilizer on rainfed low land rice. indian j. agron. 36 (1): 87-90. bangladesh agron. j. 2018, 21(2): 13-18 system productivity of wheatsesame-t. aman rice cropping pattern as influenced by varietal replacement m. maniruzzaman1*, m. robiul alam1, m. s. islam1, m. z. islam1 and m. a. islam2 1on-farm research division, bangladesh agricultural research institute, pabna 2on-farm research division, bangladesh agricultural research institute, shampur, rajshahi *corresponding author, e-mail: maniruzzaman.bari@yahoo.com (received: 21 december 2017, accepted: 25 january 2018) keywords: sustainable yield index, production efficiency, land use efficiency, rice equivalent yield abstract the study was carried out at multi location testing site, sujanagar, pabna during two consecutive years of 2011-12 and 2012-13 growing season to assess the performance of the pattern with newly released crop varieties against the existing one usually practiced by the farmers with traditional varieties in order to increase yield and economic return. the experiment was laid out in a randomized complete block design with six dispersed replications at farmer’s field. in improved pattern (ip) bari gom-26, bari til-4 and binadhan-7 variety were used for wheat, sesame and t. aman rice, respectively. on the contrary in existing pattern (ep) farmers usually use bari gom-21, local (char shira) and sharna cultivar for wheat, sesame and t. aman rice, respectively. the mean yield was recorded 4.66, 1.34 and 4.79 t ha-1 from wheat (bari gom-26), sesame (bari til-4) and t. aman (binadhan-7) respectively from the improved cropping pattern whereas average yield 3.81, 0.98 and 4.58 t ha-1 was obtained from wheat (bari gom-21), sesame (local) and t. aman (sharna), respectively from the existing pattern. two years mean data also showed that improved pattern provided about 18% higher rey compared to existing pattern. sustainable yield index and production efficiency were also found maximum with improved cropping pattern. similarly, maximum gross margin and benefit cost ratio were obtained from improved cropping pattern. introduction the major cropping pattern in bangladesh agriculture mostly consist of rice based cereal crops. cropping pattern is the yearly sequence, temporal and spatial arrangement of crops in a given crop field. a cropping pattern on an area largely depends on some factors like climate, type of soil, rainfall, agricultural technology, irrigation facilities, different inputs, marketing, transport facilities and growth of agro-industries (neena, 1998; gadge, 2003). an effective cropping pattern ensures the best efficiency of land, labor, fertilizer, irrigation water and other inputs (harwood, 1974). wheat-sesame-t. aman rice is one of the most popular and important cropping pattern in pabna region. but total productivity from this cropping patter is very much low. the causes of lower yield of the crops under wheat-sesame-t. aman rice are mainly because the farmers’ of that locality use old traditional varies of wheat, sesame and t. aman rice. those old traditional crop varieties are low yield potential, insect and disease susceptible. the farmers harvest poor yield from about:blank 14 maniruzzaman et al. local and old varieties that can be increased manifold by introducing high yielding modern varieties (alam and rahman, 2006; basak et al., 2007). therefore, the study was undertaken to assist the farmers in the drought prone areas to increase their income using proper cropping pattern with modern high yielding crop varieties. materials and methods the study was carried out at multi location testing site, sujanagar, pabna during two consecutive years of 2011-12 and 2012-13 growing season to assess the performance of the pattern with newly released crop varieties against the existing one usually practiced by the farmers with traditional varieties in order to increase yield and economic return. high yielding modern varieties of wheat, sesame and t. aman were advised to be included in place of traditional local varieties usually cultivated by farmers. wheat (bari gom-26), sesame (bari til-4) and t. aman (binadhan-7) were selected for inclusion in the improved pattern against wheat (bari gom-21), local sesame (charshira) and sharna as t. aman used to be cultivated by the farmers in their traditional existing cropping pattern. the experiment was laid out in a randomized complete block design with six dispersed replications at farmer’s field. the agronomic practices and cultural operation of crop production under improved and existing cropping patterns are presented in table 1. all field operation and management practices were closely monitored. yield and other relevant data were recorded carefully to make a comparison between the improved and existing pattern regarding yield and economic return. agronomic performance viz. production efficiency, rice equivalent yield (rey) and sustainable yield index (syi) of cropping patterns were calculated by the following formula: production efficiency production efficiency values in terms of kg ha-1 day-1 were calculated by total production in a cropping sequence divided by total duration of crops in that sequence (tomer and tiwari. 1990). production efficiency 321 321 ddd yyy ++ ++ = where, y1= yield of 1st crop and d1= duration of 1st crop of the pattern y2= yield of 2nd crop and d2= duration of 2nd crop of the pattern y3= yield of 3rd crop and d3= duration of 3rd crop of the pattern sustainable yield index (syi) sustainable yield index was worked out by the following formula suggested by krishna and reddy (1997). sustainable yield index (syi) 100 max × − = y sdymean where, y mean: estimated mean yield of a practice over years; sd: estimated standard deviation; y max: observed maximum yield in the experiment over the years. rice equivalent yield (rey) for comparison between crop sequences, the yield of all crops was converted into rice equivalent on the basis of prevailing market price of individual crop (verma and mongal, 1983). the economic indices like gross return and net system productivity of wheatsesame-t. aman rice cropping pattern 15 return and benefit cost ratio were also calculated on the basis of prevailing market price of the produces. rice equivalent yield = for economic evaluation of two different cropping sequences averaged data of two crop cycles were used. the gross cost of cultivation of different crops was calculated on the basis of different operations performed and materials used for raising the crops. gross margin, gross return and total cost of cultivation of the crops were calculated as well as benefit cost ratio (bcr) as per following formula: benefit cost ratio (bcr) = gross return (tk. ha-1)/ total variable cost (tk. ha-1) table 1. management practices of improved and existing cropping pattern parameters crops improved pattern (ip) existing pattern (ep) variety wheat bari gom-26 bari gom-21 sesame bari til-4 local charshira t. aman binadhan-7 sharna sowing/transplanting time wheat 30 november to 5 december sesame 16 to 24 april t. aman 7 to 13 august planting method wheat line sowing broadcasting sesame line sowing broadcasting t. aman line sowing line sowing fertilizer dose (n-p-k-s-zn-b kg ha1) wheat 83-28-20-20-3-2.5 sesame 48-27-23-18-0-0 t. aman 69-22-35-11-3.6-1.4 weeding (no) wheat 1 1 sesame 1 1 t. aman 2 2 irrigation/rainfed wheat 2 2 sesame rainfed rainfed t. aman 2 2 harvesting time wheat 17 to 25 march 20 to 28 march sesame 18 to 28 july 14 to 23 july t. aman 2 to 10 november 20 to 26 november field duration (days) wheat 108-112 111-115 sesame 94-96 90-92 t. aman 88-92 106-110 results and discussion grain and straw yield of the pattern grain and straw yield of wheat, sesame and t. aman rice of both the cropping patterns are presented in table 2. it was observed that wheat, sesame and t. aman rice under improved cropping pattern perform significantly higher than that of existing cropping pattern in both the year. in case of wheat the mean grain yield of bari gom-26 (4.66 t ha-1) was found higher than bari gom-21 (3.81 t ha-1). the seed yield of bari til-4 (1.34 t ha-1) was also found higher than local sesame cultivar (0.98 t ha-1). in case of t. aman rice yield of binadhan-7 (4.79 t ha-1) was found higher compare to local cultivar sharna (4.58 t ha-1). similar trend was found in case of straw yield except t. aman rice where local cultiver sharna provided higher straw yield compared to binadhan-7. in both the 14 maniruzzaman et al. year improved pattern performed better than the existing cropping pattern. this might be due to use of high yielding modern crop varieties in improved cropping pattern. on the contrary the verities used in existing cropping pattern are low yielder, insect and disease susceptible. this result was supported by the results of nazrul (2016), nazrul et al. (2013), khan et al. (2005) and hossain and wahhab (1992) table 2. grain and straw yield of different crops obtained from improved pattern (ip) and existing pattern (ep) during 2011 to 2013 years cropping patterns grain yield (t ha-1) straw yield (t ha-1) wheat sesame t. aman wheat sesame t. aman 2011-12 ip 4.56 1.36 4.81 5.54 4.8 6.5 ep 3.87 1.0 4.65 4.5 3.0 6.86 t value 28.327 12.198 2.701 26.501 12.198 -4.309 level of significance ** ** * ** ** ** 2012-13 ip 4.75 1.32 4.76 5.69 4.6 6.25 ep 3.75 0.95 4.5 4.3 2.75 6.66 t value 387.29 24.222 71.204 380.67 270.81 -44.041 level of significance ** ** ** ** ** ** mean ip 4.66 1.34 4.79 5.62 4.7 6.38 ep 3.81 0.98 4.58 4.43 2.88 6.76 ip = improved pattern, ep = existing pattern. * = significance at 5 % level and ** = significance at 1 % level rice equivalent yield rice equivalent yield of improved cropping pattern was found higher compared to existing cropping pattern in both the years (table 3). the mean rice equivalent yield 14.24 t ha-1 was obtained from improved pattern which was about 18% higher than existing pattern. this higher rice equivalent yield was might be due to inclusion of high yielding modern varieties in improved cropping pattern. production efficiency higher production efficiency was found from improved cropping pattern in both the year as compared to existing cropping pattern (table 3). the mean production efficiency of 38.56 kg ha-1 day-1 was obtained from improved pattern which was about 26% higher than existing pattern. this higher production efficiency was might be due to higher yield of modern varieties in improved cropping pattern. similar results were also observed by nazrul (2016), nazrul et al. (2013) and khan et al. (2005). sustainable yield index maximum sustainable index was also found from improved cropping pattern in both the years as compared to existing cropping pattern (table 3). the mean sustainable yield index (68.25%) was obtained from improved pattern which was about 41% higher than existing pattern. table 3. rice equivalent yield, production efficiency and sustainable yield index obtained from improved pattern (ip) and existing pattern (ep) during 2011 to 2013 years cropping patterns rice equivalent yield (t ha-1) production efficiency (kg ha-1 day-1) sustainable yield index (%) 2011-12 ip 14.22 48.53 70.95 system productivity of wheatsesame-t. aman rice cropping pattern 15 ep 12.25 39.26 48.71 2012-13 ip 14.26 48.67 66.01 ep 11.81 37.85 47.84 mean ip 14.24 48.60 68.25 ep 12.03 38.56 48.28 % increase over ep 18.37 26.04 41.36 ip = improved pattern, ep = existing pattern, price: of rice = 18 tk. kg-1; wheat = 20 tk. kg-1; mustard = 45 tk. kg-1 cost and return analysis between two cropping patterns, the improved pattern provided more profit over existing pattern during two consecutive cropping years (table 4). the mean gross return obtained from improved pattern (tk. 2,56,320 ha-1) was higher than that of existing cropping pattern (tk. 2,16,540 ha-1). higher gross margin was obtained from improved cropping pattern which was tk. 13,94,465 ha-1 against total variable cost of tk. 1,21,855 ha-1 whereas existing pattern provided lower gross margin which was tk. 97,090 ha-1 against total variable cost of tk. 1,19,450 ha-1. maximum bcr was also recorder from improved pattern (2.10) and minimum from existing pattern (1.81). table 4. cost and return of improved and existing cropping pattern during 2011 to 2013 years cropping patterns gross return (tk. ha-1) total variable cost (tk. ha1) gross margin (tk. ha-1) bcr 2011-12 ip 255960 121230 134730 2.11 ep 220500 118850 101650 1.85 2012-13 ip 256680 122480 134200 2.10 ep 212580 120050 92530 1.77 mean ip 256320 121855 134465 2.10 ep 216540 119450 97090 1.81 ip = improved pattern, ep = existing pattern. price of rice seed = 18 tk. kg-1; wheat seed= 20 tk. kg-1; mustard seed= 45 tk. kg-1 and all straw = 1 tk. kg-1 conclusion wheat-sesame-t. aman rice is one of the major cropping patterns in pabna region. this pattern could be more productive, sustainable and profitable if farmer cultivated modern high yielding varieties of wheat, sesame and t. aman rice. therefore, the farmers of this locality should cultivate bari gom-26, bari til-4 and binadhan-7 instead of bari gom-21, local charshira sesame and local cultiver sharna in their wheat-sesame-t. aman rice cropping pattern for higher system productivity and profitability. references alam, m. m. and m. m. rahman. 2006. effect of row spacing on seed yield of five varieties of rapeseed. bangladesh j. crop sci. 17(1): 163-168. 14 maniruzzaman et al. basak, n. c., j. c, pandit and m. h. khurram. 2007. on-farm evaluation of three mustard varieties under different fertilizer packages. bangladesh j. sci. ind. res. 42(3): 335-340. gadge, s. s. 2003. influence of changes in cropping pattern on farmers’ economic status. indian j. ext. edu. 39(1 and 2): 99-101. harwood, r.r. 1974. resource utilization approach to cropping system improvement. international workshop on farming systems, 18-21 november 1974, icrisat, hydarabad, india. hossain, m. a. and m. a. wahhab. 1992. demonstration cum assessment of recommended and farmer’s technologies in jute cultivation. abs. of research. agril. res. on jute, bangladesh jute research institute: p. 250. khan, m. a., m. a. quayyum, m. i. nazrul, n. sultana and m. r. a. mollah. 2005. on-farm evaluation of production potential and economics of mustardrice based improved cropping system. j. socio. res. dev. 2(1): 37-42. krishna, a. and k. a. reddy. 1997. production potential and economics of rice based cropping system in andhra pradesh. indian j. agril. sci. 67(12): 551553. nazrul, m. i. 2016. on-farm assessment of system productivity of wheatjutet. aman rice cropping pattern in sylhet region. bangladesh agron. j. 19(2): 8794. nazrul, m. i., m. r. shaheb, m. a. h. khan and a. s. m. m. r. khan. 2013. on-farm evaluation of production potential and economic returns of potatorice based improved cropping system. bangladesh agron. j. 16(2): 51-50. neena, d. 1998. interstate variation in cropping pattern in india. indian j. regi. sci. 30(2): 57-69. tomer, s. s. and a. s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35(1, 2): 30-35. verma, s. p. and s. c. mongal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2): 89-92. bangladesh agron. j. 2015, 18(2): 53-63 effect of nitrogen on weed infestation and performance of boro rice under two selected herbicides m. m. morshed1, m. n. bari1, q. a. khaliq1 and m. s. alam2 1department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 2department of soil science, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 corresponding author: manjur.morshed69@gmail.com abstract a field experiment was conducted at the experimental farm of bangabandhu sheikh mujibur rahman agricultural university (bsmrau), salna, gazipur from november 2013 to may 2014 to determine the effect of nitrogen and herbicide on weed infestation and performance of boro rice (cv. brridhan28). five nitrogen doses i.e. 0 , 50.6 , 101.2 , 151.8 and 202.4 kg ha-1 under selected pre-emergence and post-emergence herbicides along with one weed free and control (unweeded) treatment were imposed in the experiment. nine weed species was found to dominate in the experimental plots where scirpus maritimus l. showed the maximum visual abundance (58%) followed by leersia hexandra sw., paspalam distichum l. and fimbristylis miliacea l. post-emergence herbicide contributed to higher control efficiency than that in pre-emergence herbicide. post-emergence herbicide without receiving nitrogen showed the highest weed control efficiency (97.39) at 60 days after transplanting. treatment receiving n @ 200.4 kg ha-1 under post-emergence herbicide showed the highest number of tiller per hill (13.00), total dry matter (1568.6 g m-2), panicles per hill (10.60), filled grains per panicle (125.20) and grain yield (6.46 t/ha). n-dose 151.8 kg ha-1 under postemergence herbicide contributed to the second highest grain yield (6.41 t ha-1) with the highest benefit cost ratio of 1.60 but 50.6 kg n ha-1 under post-emergence herbicide showed the maximum nitrogen use efficiency of 0.49. the study revealed that nitrogen dose up to 151.8 kg ha-1 might be increased above the recommended dose under coverage of a suitable post-emergence herbicide for profitable rice production. introduction the area and production of total rice in bangladesh is about 11.35 million hectares and 31.98 mmt, respectively where boro rice contributes to the production of 18.06 mmt. however, the average yield of rice is low (4.34 t ha-1) in bangladesh (brri, 2011) compared to other rice growing countries. weed is one of the most important pests causing reduction of grain yield by 70-80% in aus rice, 3040% transplanted aman rice and 22-36% in boro rice (brri, 2009). hence, proper weed management practices are essential to obtain better yields in transplanted rice. in bangladesh, the traditional methods of weed control practices involve huge labour and at the same time it is tedious, time consuming and expensive. a wide range of pre and post emergence herbicides such as butachlor, pretilachlor, oxadiazone, pyrazosulfuron-ethyl, ethoxysulfuron either alone or supplemented with hand weeding have been found to be useful for weed management in transplanted paddy (mamun, 2011). nitrogen is a major essential plant nutrient and key input for increasing crop yield (dastan et al., 2012). however, both weed and rice plants compete for nitrogen and in a weed infested field weeds uptake n more rapidly than rice plant, particularly at high nitrogen levels (nyarko and de datta., 1993). it was found that, growth and seed production of e. crussgalli increases with increases in nitrogen rate resulting lesser nitrogen availability to the rice plants (chauhan and abugho, 2013). therefore, proper herbicide and dose of nitrogen fertilizer are both critical factors for efficacy in weed management as well as growth and productivity of rice. effects of these two factorial effects were observed individually on rice but information on the combined effect of weed control and nitrogen dose on weed infestation behavior and productivity of transplanted wetland rice are scanty under 54 morshed et al. bangladesh context. with this consideration, the present study was undertaken to determine the effect of nitrogen on weed infestation behavior, to evaluate the growth and yield of boro rice as well as to find out suitable combination of dose of nitrogen and herbicide for effective weed management and productivity of boro rice. materials and methods a field experiment was conducted at the experimental farm of the bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur under wet land condition from november to may, 2013-2014. the soil of the experimental site was silty clay of shallow red brown terrace type under salna series of madhupur tract in the agro ecological zone (aez) 28. the experimental site is situated in a sub-tropical climatic zone, characterized by heavy rainfall during the months from may to september and scanty rainfall during rest of the year. boro rice variety brridhan28 was used as test crop. two herbicides; pretilachlor (pre-emergence at 5 dat) & pyrazosulfuran-ethyl (postemergence at 15 dat) were used in the experiment. there are 12 treatments such as t1 = pretilachlor @ 1l ha-1 + nitrogen @ 0 kg ha-1, t2 = pretilachlor @ 1l ha-1 + nitrogen @ 50.6 kg ha-1, t3= pretilachlor @ 1l ha-1 + nitrogen @ 101.2 kg ha-1), t4= pretilachlor @ 1l ha-1 + nitrogen @ 151.8 kg ha-1), t5= pretilachlor@ 1l ha-1 + nitrogen @ 202.4 kg ha-1, t6 = pyrazosulfuron-ethyl @ 150g ha-1 + nitrogen @ 0 kg ha-1, t7= pyrazosulfuron-ethyl @ 150 g ha-1 + nitrogen @ 50.6 kg ha-1, t8= pyrazosulfuron-ethyl @ 150g ha-1 + nitrogen @ 101.2 kg ha-1, t9= pyrazosulfuron-ethyl @ 150g ha-1 + nitrogen @ 151.8 kg ha-1, t10= pyrazosulfuron-ethyl @ 150g ha-1 + nitrogen @ 202.4 kg ha-1, t11= control (unweeded + without nitrogen), t12= weed free (with recommended dose of n). the experiment was laid out in a randomized complete block design (rcbd) with three replications. a fertilizer dose of 77-80-55-5 kg of triple super phosphate, muriate of potash, gypsum and zinc sulfate respectively was applied in the experimental field (brri, 1999). the whole amount of fertilizers was applied as basal dose during final land preparation. urea was top-dressed in three equal installments at 20, 40 and 60 days after transplanting (dat), respectively. forty days old seedlings were uprooted from the seedbed on january 14, 2014. transplanting was done with one seedling in each hill at a spacing of 20 x 15 cm on the same day. intercultural operations such as irrigation, pest management and other necessary cultural operations were done accordingly. the crop under weed free treatment was kept weed free by continuing weeding operations every week. plant samplings were done at 15 days interval starting from 30 dat until maturity. data on different growth parameters, yield components and yield were collected. at each sampling data were recorded on the following parameters: leaf area index (lai) was measured from 30dat at 15 days interval with leaf area meter (model aam-7 hayashi denko co. tokyo, japan). leaf area index was then calculated by using the following formula as shown below: lai= leaf area for 5 hills (cm2) / land area occupied by 5 hills (cm2) crop growth rate was calculated using the following formula, cgr= ga-1 {(w2-w1) / (t2-t1)} g m-2day-1 w1= total dry weight at time t1 (g) w2= total dry weight at time t2 (g) t1= initial time (day) t2= final time (day) ga= ground area (m2) total nitrogen (tn) content was determined by micro-kjeldahl method (bremner and mulvaney, 1982) using this formula, % n of grain or straw= (t b) x n x 1.401 x s-1 x 100 t = sample titration value (ml) of standard h2so4 s = weight of soil sample in g 55 effect of nitrogen on weed infestation of boro rice under selected herbicides b = blank titration value (ml) of standard h2so4 n = strength of h2so4. nitrogen use efficiency (nue) was calculated by following formula, (olson and swallow, 1984) nue = (nuna–nuno) / nr nuna = nitrogen uptake (kg ha-1) by grain with addition of nutrient nuno = nitrogen uptake (kg ha-1) by grain without addition of nutrient nr = rate of added nutrient (kg ha-1). visual abundance of weeds was calculated through direct eye observation of standing weeds in the experimental plots at 60 dat. the scores were used as 4 = high; 3 = medium; 2 = low; 1 = very low/negligible. weed control efficiency was calculated with the following formula: weed control efficiency (wce) = {(dmc – dmt) / dmc} x 100 dmc = weed dry matter in unweeded treatment dmt = weed dry matter in weed control treatment crop was harvested at well-matured stage on the date of 14 may 2014. at maturity, five plants were harvested from each plot to record data on yield components and the plants from an area of 2.4 m2 was harvested on grain and straw yields. the data were compiled and tabulated with the help of the computer package statistix 10 and the means were separated through least significance difference (lsd) test. results and discussion considerable effects of dose of nitrogen and weed control treatments on weed infestation, weed control, crop growth and yield performance of boro rice cv. brridhan28 were observed and discussed below: weed species nine different weed species belonging to five families of which seven annuals and two perennials were found among the treatments, the most abundant weed species found was scirpus maritimus l. contributing to 58% of total weed species being followed by leersia hexandra sw. (12%) and paspalam distichum l. (9%). other important weeds were fimbristylis miliaceae l. and cyperus difformis l. the maximum average weed abundance (12%) was found in t4 treatment receiving pre-emergence herbicide along with 151.8 kg of n ha-1. in general, weed abundance increased with increase in n dose. it might be due to availability of nitrogen in soil that favoured luxuriant growth of weeds. however, post-emergence herbicide application (t6-t10) contributed to lesser abundance of weeds than those in pre-emergence one. weed control efficiency (wce) wce varied significantly due to dose of nitrogen and herbicide application. wce was inversely proportional to weed biomass, i.e. the lower the weed biomass, the higher the wce. wce increased steadily irrespective of nitrogen dose and herbicide application up to 60 dat and then decreased (fig. 1). herbicides had significant effect on wce. at 60 dat, plots treated with post-emergence herbicide showed higher wce than those with pre-emergence one. it might be due to that, the duration between application of post-emergence herbicide (15 dat) and canopy closure by rice plants allowing lesser avenue for weeds to germinate and stand establishment, which did not occur in case of pre-emergence herbicide applied at 5 dat. 56 morshed et al. fig. 1. effect of n dose and herbicide on weed control efficiency in boro rice field crop growth and development tiller dynamics: tiller growth continued up to 75 dat then decreased gradually in all the treatments probably due to mortality of ineffective tillers at later stages. at 75 dat when tiller number reached its peak, the maximum number of tillers hill-1 (17.00) was found in t10 treatment receiving 202.4 kg of n ha-1 under coverage of post-emergence herbicide, while the least (10.20) in t1 treatment without n under pre-emergence herbicide (fig. 2). data indicated that, increasing n-dose enhanced tiller production, particularly at 75 dat (table 1). however, the rate of increase was more prominent under post-emergence than under pre-emergence one. after 75 dat and onwards, tiller number started to decline until maturity in all the treatments. it might be due to that tillers that were produced at later stages did not get much light for photosynthesis, which hampered their growth and development leading to mortality. at harvest tiller number was also the highest in t10 treatment, which was being followed by t9, t5 and t4 treatments in descending order (table 1). tiller mortality rate was measured as the percent change of tiller number from the period of peak tiller growth to harvest (table 1). the treatment t7 showed the maximum tiller mortality rate (28.18%) which is followed by t10 (23.53%) and t9 (18.54%) under post emergence herbicide. among the treatments under pre-emergence herbicide, t4 showed maximum tiller mortality rate (15.21%) which is followed by t5 (11.93%) and t1 (11.77%), while the least (5.89%) was found in t3 under pre emergence herbicide next to unweeded (control) treatment. in general, treatments under pre emergence herbicides incurred lower mortality rate than that in treatments under post-emergence herbicides. 57 effect of nitrogen on weed infestation of boro rice under selected herbicides fig. 2. effect of n dose and herbicide on tiller dynamics in boro rice table 1. tiller mortality rate as affected by different nitrogen doses under two selective herbicides tiller hill-1treatment 75 dat harvest % change (75 dat to harvest) t1(h1n1) 10.2 9 -11.77 t2(h1n2) 11.6 10.33 -10.95 t3(h1n3) 12.4 11.67 -5.89 t4(h1n4) 14 11.87 -15.21 t5(h1n5) 14 12.33 -11.93 t6(h2n1) 11.07 9.07 -18.07 t7(h2n2) 13.27 9.53 -28.18 t8(h2n3) 13.53 11.67 -13.75 t9(h2n4) 15.8 12.87 -18.54 t10(h2n5) 17 13 -23.53 t11(cont) 8.33 7.93 -4.80 t12(wf) 13 11.2 -13.85 cv (%) 4.15 5.4 lsd0.05 0.90 2.55 leaf area index (lai): lai sharply increased up to 75 dat, and then declined steadily irrespective of treatment. nitrogen doses had significant effect on lai (fig. 3). among the treatments, t10 (h2n5) contributed to the highest lai whereas control (t11) treatment showed the lowest lai throughout the sampling periods. at 75 dat, , the maximum lai (3.887) was found in t10 treatment (202.4 kg n ha-1 ) under coverage of post emergence herbicide. other than control treatment, the lowest lai (1.828) was noticed in t1 treatment during the same period. data indicated that treatments receiving higher doses of n particularly under post emergence herbicide contributed to higher lai. this result was in accordance with the earlier findings of rahman et al. (2007). 58 morshed et al. fig. 3. effect of n dose and herbicide on leaf area index in boro rice total dry matter (tdm) production tdm production was significantly influenced by nitrogen dose associated with selected herbicides (fig. 4). at the harvest, t10 produced the maximum tdm of 1568.6 g m-2 which was followed by 1490.2 g m-2 in t9 treatment and 1335.3 g m-2 in t12 treatment (weed free). similar trend was found in case of pre-emergence herbicide treated plots. it might be due to that higher nitrogen dose enhanced higher vegetative growth and carbohydrate assimilation in the crop plants. azarpour et al. (2014), azarpour et al. (2011) and bannayan et al. (2005) reported similar results about changes of dry weight under nitrogen fertilizer application. fig. 4. effect of n dose and herbicide on total dry matter production in boro rice apart from control treatment, the lowest tdm (1018 g m-2 ) was produced in t1 treatment under preemergence herbicide. this reduction in tdm might be due to lower weed control efficiency in this treatment increased nutrient competition with rice crop and lower nitrogen availability for crop growth. yield performance of boro rice the maximum grain yield of 6.46 t ha-1 was recorded in t10 treatment which was followed by 6.41 t ha-1 in t9 and 6.34 t ha-1 in t5 (table 2). the highest grain yield in t10 treatment was the cumulative effect of the highest tiller hill-1 (13.00), panicle hill-1 (10.60) and number of filled grains panicle-1 59 effect of nitrogen on weed infestation of boro rice under selected herbicides (125.20). data indicated that post emergence herbicide treated plots performed better in terms of yield contributing characters as well as grain yield compared to those under pre-emergence herbicide treatment (table 2; table 3). it might be due to that, rice plants under coverage of post-emergence herbicide responded well to increasing doses of n, thus resulting higher tillering, higher panicle growth as well as higher number of fertile grains panicle. the positive relationship between tiller and panicle production was also stronger under post-emergence herbicide than in pre-emergence one (fig. 5). however, the benefits were more prominent under post-emergence herbicide than under preemergence one (table 2; table 3). particularly, grain filling process was more favourably influenced by n-dose when it occurred under post-emergence herbicide coverage (fig. 6). table 2. effect of nitrogen dose on yield performance in boro rice under two selective herbicides treatme nt tillers/ hill panicles/ hill filled grains/ panicle unfilled grain / panicle 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) hi t1 (h1n1) 9.00 f 6.73 e 100.73 d 3.77 b 22.53 c 3.03 d 3.54 e 0.47 a t2 (h1n2) 10.33 de 7.27 de 116.27 c 4.17 b 23.55 ab 5.30 b 5.53 cd 0.49 a t3 (h1n3) 11.67 bc 8.00 cd 116.77 bc 5.10 a 23.61 ab 5.87 ab 6.10 bc 0.49 a t4 (h1n4) 11.87 bc 8.80 bc 122.40 abc 5.17a 23.08 abc 6.10 a 6.37 bc 0.49 a t5 (h1n5) 12.33 ab 10.33 a 124.37 a 5.30 a 23.85 a 6.34 a 7.60 a 0.46 ab t6 (h2n1) 9.07 f 7.07 de 121.27 abc 3.47 bc 22.58 c 3.19 d 4.47 de 0.42 b t7 (h2n2) 9.53 ef 7.27 de 122.17 abc 4.17 b 22.80 bc 5.35 b 5.57 cd 0.49 a t8 (h2n3) 11.67 bc 9.60 ab 123.57 abc 5.23 a 23.52 ab 5.82 ab 5.85 bc 0.50 a t9 (h2n4) 12.87 a 10.07 a 123.67 ab 5.20 a 23.66 ab 6.41 a 6.79 ab 0.49 a t10 (h2n5) 13.00 a 10.60 a 125.20 a 5.67 a 23.83 a 6.46 a 6.91 ab 0.48 a t11 (cont) 7.93 g 7.33 de 75.70 e 2.87 c 23.56 ab 1.78 e 2.06 f 0.47 a t12 (wf) 11.20 cd 9.67 ab 120.17 abc 4.17 b 23.26 abc 4.52 c 4.63 de 0.49 a cv (%) 5.40 8.27 3.73 9.16 2.36 8.64 7.29 5.74 lsd (0.05 ) 0.99 1.19 7.32 0.70 0.93 0.73 1.21 0.046 table 3. changes in grain yield in relation to weed free and control plots. treatment grain yield (t ha-1) average grain yield (t ha-1) % change from weed free % change from control 60 morshed et al. t1(h1n1) 3.03 -32.96 70.22 t2(h1n2) 5.3 17.26 197.75 t3(h1n3) 5.87 29.87 229.78 t4(h1n4) 6.1 34.96 242.70 t5(h1n5) 6.34 5.328 40.27 256.18 t6(h2n1) 3.19 -29.42 79.21 t7(h2n2) 5.35 18.36 200.56 t8(h2n3) 5.82 28.76 226.97 t9(h2n4) 6.41 41.81 260.11 t10(h2n5) 6.46 5.446 42.92 262.92 t11(cont) 1.78 -60.62 t12(wf) 4.52 153.93 fig. 5. relationship between total tiller production and panicle formation efficiency of boro rice under two selected herbicides fig. 6. relationship between n dose and filled grains nitrogen use efficiency the highest grain-n content (1.40%) was recorded in t10 treatment receiving 202.4 kg n ha-1, while the least (0.77%) was found in t1 treatment receiving no n. data revealed that, with the increase in applied n, n-uptake by rice plants also increased. the relationship between n dose and grain-n 61 effect of nitrogen on weed infestation of boro rice under selected herbicides content was stronger in post emergence herbicide than that in pre-emergence herbicide in case of grain yield of rice (fig. 7). it might be due to that, under post emergence herbicide coverage translocation of photosynthate in grain and n-utilization were higher as driven by stronger vegetative growth of rice plants during late vegetative and grain filling stages with higher n dose coupled with lesser weed infestation . data indicated that, n-use efficiency was higher when n-dose was lower (table 4). it might be due to that, under higher n-dose, leaching, volatilization, uptake by weed plants and other losses were higher, thus resulting lesser availability of applied n to the crop plants. table 4. effect of n dose and herbicide on nitrogen use efficiency of boro rice treatment urea kg ha-1 applied n kg ha-1 grain yield (t ha-1) n% grain n uptake (kg ha-1) nue t1 (h1n1) 0 0 3.03 0.77 23.41 t2 (h1n2) 110 50.6 5.30 0.89 46.96 0.47 t3 (h1n3) 220 101.2 5.87 1.21 71.25 0.47 t4 (h1n4) 330 151.8 6.10 1.31 79.71 0.37 t5 (h1n5) 440 202.4 6.34 1.35 85.78 0.31 t6 (h2n1) 0 0 3.19 0.78 24.89 t7 (h2n2) 110 50.6 5.35 0.93 49.89 0.49 t8 (h2n3) 220 101.2 5.82 1.07 62.46 0.37 t9 (h2n4) 330 151.8 6.41 1.21 77.82 0.35 t10 (h2n5) 440 202.4 6.46 1.40 90.43 0.32 t11 (cont) 0 0 1.78 0.84 14.94 t12 (wf) 220 101.2 4.52 0.98 44.30 0.29 fig. 7. relationship between n dose and grain n-content of boro rice as affected by herbicide benefit cost ratio (bcr) was varied from 0.50 to 1.60 among the treatments. in general, treatments with higher nitrogen dose, showed higher bcr irrespective of herbicide. again, treatments under post emergence herbicide showed higher bcr than that in treatments under pre-emergence herbicide. the highest bcr (1.60) was found in t9 treatment receiving 151.8 kg n ha-1 under post emergence herbicide, which was followed by t10, t5 and t4 treatments. table 5. gross return, cultivation cost, net return and benefit cost ratio of different treatment 62 morshed et al. yield cultivation costtreatment grain (t ha-1) straw (t ha-1) gross return (tk.) other cost (except weeding and urea) urea fertilizer cost (tk.) herbicide cost (tk.) total cost (tk.) net return (tk.) benefit cost ratio t1 (h1n1) 3.03 3.54 67638 79934 0 2190 82124 -14486 0.82 t2 (h1n2) 5.30 5.53 116963 79934 3370 2190 85494 31469 1.37 t3 (h1n3) 5.87 6.10 129643 79934 5570 2190 87694 41949 1.48 t4 (h1n4) 6.10 6.37 134739 79934 7770 2190 89894 44845 1.50 t5 (h1n5) 6.34 7.60 141971 79934 9970 2190 92094 49876 1.54 t6 (h2n1) 3.19 4.47 72762 79934 0 990 80924 -8162 0.90 t7 (h2n2) 5.35 5.57 118047 79934 3370 990 84294 33753 1.40 t8 (h2n3) 5.82 5.85 128089 79934 5570 990 86494 41595 1.48 t9 (h2n4) 6.41 6.79 141861 79934 7770 990 88694 53167 1.60 t10 (h2n5) 6.46 6.91 143006 79934 9970 990 90894 52112 1.57 t11 (cont) 1.78 2.06 39695 79934 0 0 79934 -40239 0.50 t12 (wf) 4.52 4.63 99670 79934 5570 10140 95644 4026 1.04 note: price of grain and straw were tk. 20.00 and tk. 2.00, respectively conclusion treatment receiving 202.4 kg n ha-1 under post-emergence herbicide contributed to the highest grain yield and grain nitrogen content. but, the highest benefit cost ratio was obtained when n was applied @ 151.8 kg ha-1 of the recommended dose under post emergence herbicide application. references azarpour, e., m. moraditochaee and h. r. bozorgi. 2014. effect of nitrogen fertilizer management on growth analysis of rice cultivars. int. j. biosci. vol. 4, no. 5, p. 35-47 azarpour, e., m. k. motamed, m. moraditochaee and h. r. bozorgi. 2011. effect of nitrogen fertilizer and nitroxin biofertilizer management on growth analysis and yield of rice cultivars (iran). world applied sciences journal 14(2), 193-198. bannayan, m, k. kobayashi, h. y. kim, m. lieffering, m. okada and s. miura. 2005. modeling the interactive effects of atmospheric co2 and n on rice growth and yield. field crops research: 93, 237-251. http://dx.doi.org/10.1016/j.fcr.2004.10.003 bremner, j. m. and c. s., mulvaney. 1982. nitrogen-total. in: a.l. page, r.h. miller (eds). methods of soil analysis. part 2. 2nd ed. agron. monogr. 9. asa and sssa, madison, wi. pp.595-624. brri (bangladesh rice research institute). 1999. adhunik dhaner chash (in bengali). bangladesh rice research institute, joydebpur, gazipur, pp:12 brri (bangladesh rice research institute). 2011. adhunik dhaner chash (in bengali). bangladesh rice research institute, joydebpur, gazipur, pp: 5. brri (bangladesh rice research institute). 2009. brri annual internal review 2007-2008. soil science division. bangladesh rice research institute, gazipur-1701. 63 effect of nitrogen on weed infestation of boro rice under selected herbicides chauhan b, s. and s. b. abugho, 2013. growth and echinochloa glabresces in response to cultivar and density. journal of crop improvement. 27(4): 391-405 dastan, s., m. siavoshi, d. zakavi, a. ghanbaria-malidarreh, r. yadi, e. ghorbannia delavar, and a. r. nasiri. 2012. application of nitrogen and silicon rates on morphological and chemical lodging related characteristics in rice (oryza sativa l.) north of iran. journal of agricultural science, 4(6). mamun, m. a. a., r. sultana, m. a. sidique, m. s. jahan and s. pramanik, 2011. efficacy of different commercial product oxadiazon and pyrazosulfuran-ethyl on rice and associate weeds in dry season rice cultivation. world journal of agricultural sciences 7(3): 341-346, 2011 nyarko, a. k. and s. k. de datta, 1993. effect of light and nitrogen and their interaction on the dynamics of rice-weed competition. weed res. 33:1-8. olson, r.v., and c.w. swallow. 1984. fate of labeled nitrogen fertilizer applied to winter wheat for five years. soil sci. soc. am. j. 48:583-586. rahman, m. h., m. h. ali, m. m. ali and m. m. khatun. 2007. effect of different level of nitrogen on growth and yield of transplant aman rice cv. brridhan32. int. j. sustain. crop prod. 2(1): 28-34. bangladesh agron. j. 2017, 20 (1): 31-36 application of ash for amelioration of salinity effect in rice a. h. f. fahim1*, m. a. kader2, m. s. nahar1 , m. a. wadud1 and m. a. islam3 1scientific officer, spices research centre, bari, shibganj, bogra, bangladesh. 2department of agronomy, bangladesh agricultural university, mymensingh, bangladesh. 3senior scientific officer, spices research centre, bari, shibganj, bogra, bangladesh. *corresponding author, e-mail: fahimkbd@gmail.com keywords: salinity, ash, stress, rice, brri dhan47 abstract agricultural land use in coastal area covers 53% and the lands are mostly affected by salinity. besides, the average yield of rice in these areas is very low due to salinity. although, brri has developed salt registrant rice varieties, the average production can be improved through soil management. thus, a pot experiment was conducted in the net house of department of agronomy, bangladesh agricultural university, mymensingh, during march to august 2010 to investigate the ameliorative effect of ash application on yield and yield attributes of rice under various salinity levels. rice var. brri dhan47 (a salt tolerant variety) was used in the experiment. the sodium chloride induced salinity levels were 20, 40, 60, 80 and 100 mm nacl and the levels of ash applied were 1.5, 3, 4.5 and 6 t ha-1. results revealed that the different levels of salinity had significant adverse effect on plant height, tillers hill-1, panicle hill-1, grains panicle-1, 1000-grain weight, grain yield, biological yield and harvest index. all the plants eventually died when they were exposed to salinity level of 40 mm nacl or more and could not survive up to maturity. application of ash enhanced the yield attributes and yield of rice under different salinity levels compared to those without ash. it was concluded that application of ash at the rate of 6 t ha-1 ameliorated the salinity stress effect on rice yield of brri dhan47. introduction in bangladesh, over 30% of the net cultivable area lies in the coastal area (rasel et al, 2013). out of 2.85 million hectare of coastal and off shore areas, about 0.833 million hectares are arable lands, which constitute about 52.8 % of the net cultivable area in 64 upzilla of 13 districts (rasel et al, 2013). this area is largely affected by varying degrees of soil salinity. agricultural land uses in these areas are very poor and cropping intensity is very low. salinity largely reduces the yield of rice in the coastal areas of the country mainly in khulna, patuakhali, noakhali and chittagong districts and in the island of bay of bengal like bhola, hatiya and sandwip (brammer, 1971). salinity level of 4 dsm-1 is considered as critical level for rice. however, rice exhibits considerable intra-specific variability in resistance to salinity (flowers and yeo, 1981; maiti et al., 2008). application of ash to the soil brought about linear increases in soil aeration, water holding capacity, soil total nitrogen, exchangeable bases and cat ion exchange capacity, but reduced soil bulk density and acidity. ash supply si to the soil which helps the plants to ameliorate the salinity stress (ma, 2004; liang et al., 2003). si is beneficial for growth of many plants under various a biotic (e.g. salt, drought and metal toxicity) and biotic (plant diseases and pests) mailto:fahimkbd@gmail.com 32 fahim et al. stresses (ma, 2004; liang et al., 2003). a number of possible mechanisms are reported through which si may increase salinity tolerance in plants (liang et al., 2003), including increased plant water status (romero et al., 2006), immobilization of toxic na+ ion (liang et al., 2003), reduced na+ uptake in plants and enhanced k+ uptake (tahir et al., 2006; liang et al., 2005; yeo et al., 1999) and higher k+: na+ selectivity (hasegawa et al., 2000). in particular, si deposition in the endodermis is proposed to restrict na+ transport along a “transpirational by pass” route from root to shoot in rice (gong et al., 2006). therefore, the present study was under taken to investigate the ameliorative effect of ash on grain yield and yield attributes of rice var. brri dhan47 under various salinity levels. materials and methods the experiment was conducted at the net house of the department of agronomy, bangladesh agricultural university (bau), mymensingh during the period from march to august, 2010. the experimental site was located at 24o n latitude and 940 e longitude and 18 meter above sea level. the experimental site belongs to the agro-ecological zone of the old brahmaputra floodplain (aez 9). the soil was collected within 6 cm from the top soil. the experimental soil was loamy in texture having a soil ph value of 6.43, moderate in organic matter content (table 1). after collection, the soil was dried in sun and loosened. all the inert matter was removed. the pots were filled up by soil. bangladesh rice research institute (brri) has developed var. brri dhan47 as a salt tolerant variety for boro season as the test crop. this variety can tolerate 12-14 dsm-1 salinity at seedling stage and 6 dsm-1 salinity for whole life the var. brri dhan47 matures within 150 days after transplanting. it attains a plant height of about 105 cm. the average yield of brri dhan47 is 6.1 tha-1 under normal condition and around 4 tha-1 in saline (brri, 2007). five level of ash (viz. 0, 1.5, 3, 4.5 & 6 tha-1) and six salinity level (viz. 0, 20, 40, 60, 80 & 100 mm nacl) were used as treatment variables. the experimental was laid put in a factorial randomized complete block design with five replications. the total number of pots used in this study was 150 (6 x 5 x 5). seeds of var. brri dhan47 were collected from brri gazipur. seeds were soaked into water in buckets for 24 hours and then taken out of water and incubated in gunny bags for sprouting. sprouted seeds were sown on 21 march 2010 in the nursery bed.. plastic pots were selected for the experiment to check the loss of saline water. the size of the pot was 13.5 cm diameter in top and 30 cm in height. each of the pots was filled with 14 kg of the collected soil and fertilized with urea 25, tsp13, mop 9 , gypsum 8 and zinc sulphate 1.5 g/ pot. the total amount of tsp, mop, gypsum and zinc sulphate and one third urea was applied during the final pot preparation and rest of the urea was top dressed at 20 and 40 days after transplanting (dat). seedlings were uprooted from nursery bed on 27 april 2010 and transplanted immediately at 3 seedlings hill-1. the insecticide basudin 10 g @ 20 kg ha-1 were applied to control rice stem borer. the salinity was applied at tillering stage and ash was applied at final pot preparation mixing within 6cm of the potted top soil. the roof of the net house was covered with thin polythene sheet to protect the pots from rain water. harvesting was done on 30 august 2010. data on plant height, tillers hill-1, grains panicle-1, 1000-grain weight, grain yield (t ha-1), straw yield (t ha-1) and harvest index (%) were recorded properly. harvest index (hi) was calculated following the formula given below (kozak et al., 2007) grain yield harvest index (hi) = × 100 biological yield 33 application of ash for amelioration of salinity effect in rice the collected data were analyzed statistically following the analysis of variance (anova) technique and the mean difference were adjudged by duncan’s multiple range test (dmrt) using the statistical computer package program mstat-c (gomez and gomez, 1984). table 1. initial nutrient status of the potted soil soil parameters content soil ph 6.2 organic carbon (%) 1.25 organic matter (%) 1.67 total nitrogen (%) 0.10 available phosphorus (ppm) 26.00 available potassium (me/100 g) 0.14 available sulphur 13.90 source: soil science laboratory, department of soil science, bau, mymensingh results and discussion effect of salinity levels on yield and yield attributes of rice var. brri dhan47 among the different salinity levels, seedlings of 0 mm nacl and 20 mm nacl were survive up to maturity but the seedlings of 40, 60, 80 & 100 mm nacl were died (table 2). the tallest plant (100 cm), higher number of tillers hill-1 (24) and panicle hill-1 (21) was recorded from control treatment (0 mm nacl) whereas the shortest plant (97 cm), lower number of tillers hill-1 (22) and panicles hill-1 (19) was recorded from 20 mm nacl salinity level. hasanuzzaman et al. (2009) reported that the plant height decreased with increasing salinity level. zeng and shannon (2000) stated that there were significant reductions in tiller number at higher salt levels. the higher number of grains panicle-1 (94) and 1000-grain weight (25.67 g) was recorded in control treatment (0 mm nacl) whereas the lower number of grains panicle-1(93) and 1000 grains weight (24.67 g) was recorded when applied 20 mm nacl salinity level. islam (2004) reported that number of grains panicle-1 decreased with increased salinity levels. also mortazainezhad et al. (2006) was observed that 1000-grains weight was negatively influenced by different salinity levels in the rice cultivars. table 2. effect of salinity on yield and yield attributes of rice var. brri dhan47 salinity levels plant height (cm) tillers hill-1 (no.) panicle hill-1 grains panicle-1 (no.) 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) s0 100a 24 a 21a 94a 25.67a 4.33a 7.22a 33.17a s1 97 b 22b 19b 93b 24.67b 4.02b 5.98b 33.15b s2 s3 s4 s5 lsd (0.05) 1.49 0.51 0.72 3.66 0.35 0.08 0.21 0.98 cv (%) 8.10 11.89 19.48 20.70 9.59 11.78 16.85 15.80 s0= 0 mm nacl, s1= 20 mm nacl, s2= 40 mm nacl, s3= 60 mm nacl, s4= 80 mm nacl and s5= 100 mm nacl. 34 fahim et al. the higher grain yield (4.33 t ha-1), straw yield (7.22 t ha-1) and harvest index (33.17%) was recorded from control treatment (0 mm nacl). on the other hand, the lower grain yield (4.02 t ha-1), straw yield (5.98 t ha-1) and harvest index (33.15%) was recorded from the salinity level 20 mm nacl. sexcion et al. (2009) reported that grain yield decreased with increasing salinity levels. the seedlings of 40, 60, 80 & 100 mm nacl were died after salt application. effect of ash on yield and yield attributes of var. brri dhan47 different level of ash had significant effect on yield and yield attributes of brri dhan47 (table 3). the maximum plant (101 cm) was recorded from 6 tha-1 ash which was identical to 4.5 t ha-1 ash whereas the shortest plant (95 cm) from the control treatment. ogbodo et al. (2009) stated that plant height increase with the increasing ash level. the higher number of tillers hill-1 (26) was recorded from the treatment 6 t ha-1 ash which was identical to 4.5 t ha-1 ash (24) whereas the lower number of tillers hill-1 (20) from control. higher number of panicles hill-1 (23), grains panicle-1 (100) and 1000-grain weight (26.98 g) was recorded from the treatment 6 t ha-1 ash whereas the lower number of panicle hill-1 (15), grains panicle-1 (83) and 1000grains weight (22.41 g) from the control.. the maximum grain yield (4.46 t ha-1) was recorded from 6 t ha-1 ash, which was identical to the treatment 4.5 t ha-1 ash (4.45 t ha-1) followed by 3 t ha-1 ash (4.20 t ha-1). the lowest grain yield (3.70 t ha-1) was recorded from the control treatment. similarly, subramoniam and chandrasekaran (2005); sudhakar et al. (2004) stated that the grain yield increased with the increasing level of ash. the highest straw yield (6.93 t ha-1) and harvest index (35.40%) was recorded from the treatment 6 t ha-1 ash whereas the lowest straw yield (6.19 t ha-1) and harvest index (31.17%) from control treatment (0 t ha-1 ash). table 3. effect of ash on yield and yield attributes of rice var. brri dhan47 levels of ash plant height (cm) tillers hill-1 (no.) panicle hill-1 grains panicle-1 (no.) 1000-grain weight (g) grain yield (tha-1) straw yield (tha-1) harvest index (%) a0 95 b 20d 15b 83b 22.41c 3.70c 6.15a 31.17b a1 97 ab 22cd 17b 93ab 24.41b 4.02bc 6.38a 31.8ab a2 98ab 23bc 21a 97ab 23.43ab 4.20ab 6.70a 32.04ab a3 101a 24ab 22a 99a 26.62a 4.45a 6.84a 35.34a a4 101a 26a 23a 100a 26.98a 4.46a 6.93a 35.40a lsd (0.05 ) 1.36 0.47 0.66 3.34 0.32 0.07 0.19 0.89 cv (%) 8.10 11.89 19.48 20.70 9.59 11.78 16.85 15.80 a0 = control, a1 = 1.5 t ha-1, a2 = 3 t ha-1, a3=4.5 t ha-1, a1= 6 t ha-1 interaction of ash and salinity levels on yield and yield attributes of rice var. brri dhan47 the interaction effect of ash and salinity levels had significant effect on the yield and yield attributes of rice var. brri dhan47 (table 4). the tallest plant (102 cm) was recorded from the treatment combination of 0 mm nacl x 6 t ha-1 ash which was identical to 0 mm nacl x 4.5 t ha-1 ash (102 cm) whereas, the shortest plant (92 cm) was recorded when no ash was applied with salinity level 20 mm nacl. the number of tillers hill-1 was higher (26) in the treatment combination of 0 mm nacl x 6 t ha-1 ash which was identical to 0 m m nacl x 4.5 t ha-1 ash (25) followed by 20 m m nacl x 6 t ha-1 ash (25) whereas, lower (19) in the treatment combination of 20 mm nacl x 0 t ha-1 ash. the number of panicles hill-1 (23), grains panicle-1 35 application of ash for amelioration of salinity effect in rice (101) and 1000-grain weight (21.36 g) was higher in 0 mm nacl x 6 t ha-1 ash and lower number of panicles hill-1 (15), grains panicle-1 (76) and 1000-grain weight (17.20) was obtained from 20 mm nacl x 0 t ha-1 ash. the maximum grain yield (4.54 t ha-1) was recorded from the treatment combination of 0 mm nacl x 6 t ha-1 ash which was identical to 0 mm nacl x 4.5 t ha-1 ash (4.52 t ha-1) followed by 20 mm nacl x 6 t ha-1 ash (4.39 t ha-1).the lowest grain yield (3.49 t ha-1) was obtained from the treatment combination 20 mm nacl x 0 t ha-1 ash. the harvest index was higher (37.32%) in the treatment combination 20 mm nacl x 4.5 t ha-1 ash which was identical to 20 mm nacl x 6 t ha-1 ash (37.10%) and lower (29.81%) in 20 mm nacl x 0 t ha-1 ash. table 4. interaction of ash and salinity levels on yield and yield attributes of rice vr. brri dhan47 interactions plant height (cm) tillers hill-1 (no.) panicle hill-1 grains panicle-1 (no.) 1000-grain weight (g) grain yield (tha-1) straw yield (tha-1) harvest index (%) a0s0 98abc 21d 15d 91b 22.49e 3.94cd 32.51bcd 32.51bcd a0s1 92d 19e 15d 76c 22.36e 3.49e 29.81e 29.81e a1s0 98abc 22d 20bc 93ab 24.55d 4.27b 33.14bc 33.14bc a1s1 95cd 21d 15d 94ab 24.29d 3.78d 30.46de 30.46de a2s0 99ab 25bc 23a 99ab 26.00b 4.35ab 33.01bc 33.01bc a2s1 97bc 22d 19c 95ab 24.77cd 4.04c 31.05cde 31.05cde a3s0 102a 25ab 22a 101a 27.54a 4.52a 33.38bc 33.38bc a3s1 101ab 24c 21ab 98ab 25.70bc 4.38ab 37.32a 37.32a a4s0 102a 26a 23a 101a 27.76a 4.54a 33.70b 33.70b a4s1 101ab 25abc 22a 98ab 26.23b 4.39ab 37.10a 37.10a lsd (0.05) 0.61 0.21 0.29 1.98 0.19 0.04 0.53 0.53 cv(%) 8.10 11.89 19.48 20.70 9.59 11.78 15.80 15.80 a0 = control, a1 = 1.5 tha-1, a2 = 3 tha-1, a3=4.5tha-1, a1=6 tha-1, s0= 0 mm nacl and s1= 20 mm nacl. conclusion it can be concluded that, application of ash ameliorated the salinity stress effect on rice yield. it was also found that, the salt tolerance level of rice var. brri dhan47 was 20 mm nacl when cultivated with 6 ton ha-1ash . references brammer, h. 1971. agricultural development possibilities in bangladesh. soil survey project technical report no. 2. fao, rome. flowers, t. j. and a. r. yeo. 1981. ion relations of plants under drought and salinity. aust. j. plant physiol. 13: 75-91. gomez, h. c. and a. a. gomez. 1984. statistical procedures for agric. res., john wiley and sons. new york, p. 680. gong h. j., d. p. randall and t. j. flowers. (2006). silicon deposition 36 fahim et al. in the root reduces sodium uptake in rice (oryza sativa l.) seedlings by reducing bypass flow. plant cell environ. 29: 1970–1979. hasanuzzaman, m., m. fujita, m. n. islam, k. u. ahamed and k. nahar. 2009. performance of four irrigated rice varieties under different levels of salinity stress. int. j. integrative biol. 6(2): 85-90. hasegawa, p., r. a. bressan, j. k. zhu and h. j. bohnert. 2000. plant cellular and molecular responses to high salinity. annu. rev. plant mol. biol. 51: 463-499. kozak, m., s. samborski, m. s. kang and j. rozbicki. 2007. applying statistics for nonsequential yield component analysis. plant, soil and environment. 53(10): 456−463. liang, y. c., w. q. zhang, j. chen and r. ding. 2005. effect of silicon on h+atpase and h+ppase activity, fatty acid composition and fluidity of tonoplast vesicles from roots of saltstressed barley (hordeum vulgare l.). j. environ. exp. bot. 53: 29-37. liang, y. c., q. chen, q. liu, w. zhang and r. ding. 2003. effects of silicon on salinity tolerance of two barley cultivars. j. plant physiol. 160: 1157-1164. ma, j. f. 2004. role of silicon in enhancing the resistance of plants to biotic and abiotic stresses. j. soil sci. plant nutrition. 50: 11-18. maiti, r., p. vidyasagar and p. p. banerjee. 2008. characterization of salinity tolerance in rice ( oryza sativa l.) genotypes at the germination and seedling stages. acta agronomica hungarica 56(2): 139-147· mortazainezhad, f., r. khavarinejad and m. emami. 2006. study of some parameters of yield and proline in rice plants under nacl salinity stress. j. new. agric. sci. 2(4): 93-98. ogbodo, e. n. 2009. changes in the properties of an acid soil amended with burnt rice husk and the effect on the growth and yield of pepper at abakaliki south eastern nigeria, am. eurasian j. sustain. agric. 3(3): 579-586. rasel, h. m., m. r. hasan, b. ahmed and m. s. u. miah. 2013. inves tigation of soil and water salinity, its effect on crop production and adaptation strategy. international j. of water res. and env. eng. 5(8): 475-481. subramoniam, s. r. and a. chandrasekaran. 2005. chemical properties of lateritic soil and yield of rice as influenced by addition of fly ash. international rice res. notes. int. rice res. inst. manila, philippines. 30(1): 35-37. sudhakar, p. c., j. p. singh and s. kalyan. 2004. effect of silicon sources and fertility levels on transplanted rice. international rice res. notes. int. rice res. inst. (irri), manila, philippines. 29(2): 61-63. suzuki s., j. f. ma, n. yamamoto, t. hattori, m. sakamoto and t. umezawa. 2012. silicon deficiency promotes lignin accumulation in rice. plant biotechnol. 29: 391–394. tahir, m., a. rahmatullah, t. aziz, m. ashraf, s. kanwal and a. muhammad. 2006. beneficial effects of silicon in wheat under salinity stress-pot culture. pak. j. bot. 38: 1715-1722. yeo, a. r., s. a. flowers, g. rao, k. welfare, n. senanayake and t. j. flowers. 1999. silicon reduces sodium uptake in rice (oryza sativa l.) in saline conditions and this is accounted for by reduction in transpirational bypass flow. plant cell environ. 22: 559-565. zeng. l. h. and m. c. shannon. 2000. salinity effects on seedling growth and yield components of rice. crop sci. society america, madison, usa. 40(4): 996-1003. https://www.researchgate.net/profile/ratikant_maiti bangladesh agron. j. 2017, 20 (1): 7-12 on-farm verification of linseed and sesame variety for fallow-fallow-t aman rice cropping system in sylhet region of bangladesh m. i. nazrul on-farm research division, bangladesh agricultural research institute (bari) e-mail: mi_nazrul@yahoo.com; m.i.nazrul@gmail.com key words: sesame, linseed, on-farm trial, fallow land, cropping system abstract a field experiment was conducted during rabi and kharif seasons of 2014-15 and 2015-16 to find out suitable linseed and sesame genotypes to fit in the fallow-fallowt. aman rice cropping system under aez 20 in sylhet region of bangladesh. this experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. it was revealed that among the different linseed varieties, the genotype zokiganj-local gave the maximum number (31.40) of capsules plant-1 and 1000-seed weight (4.01g) with the highest seed yield (1003 kg ha-1). similarly, sesame var. bari til-4 provided maximum number of capsules plant-1 (71.33), seeds plant-1 (70.33) and highest 1000-seed weight (3.012g), which resulted the highest seed yield (1150 kg ha-1) yield in arable fallow land of sylhet region. the lowest seed yield 782 and 840 kg ha-1 of linseed and sesame was produced by the genotypes patuakhali local and the var. bari til-3, respectively. introduction sylhet region of eastern bangladesh is dominated by drought prone rice based rainfed ecosystem as about 182000 ha of arable land remainse fallow during kharif 1 season. sesame (sesamum indicum l.) is one of the most ancient oilseed crops (ashri, 1998; bedigan and harlan, 1986) of the world. it is the second largest source of edible oil in bangladesh next to brassica both in respect of acreage and production (anonymous, 1989) and can be cultivated both in rabi (winter) and kharif (summer) season. it occupied 38866 ha of land and produced 25000 tons of seed with a yield of 640 kg ha-1 (bbs, 2004). sesame seeds have special significance for human nutrition on account of its high content of sulfur amino acids and phytosterols (pathak et al., 2014). sesame oil-cake is a good feed for poultry, fish, cattle, goat, sheep etc. sesame is a drought tolerant oil seed crop, which are grown successfully in the early summer (march-may) of bangladesh under rain fed condition. linseed (linum usitatissimum l.) is an annual herb belonging to the family linaceae, which is commonly found in asia (fernald, 1950). linseed is basically known as a crop of industrial importance and used in paint and varnish industries, which contains 33-43 % oil of drying type and 24 % protein (vereshagin et. al., 1965). its oil has high percentages of unsaturated fatty acids and 17 % linoleic acid (mchughen, 1990). it is also used for making linoleum, oil cloth, printer’s ink, soap and patent leather. linseed can play an important role in the production of alternative diesel fuel (nabi and hoque 2008; ariharan et al, 2015). the climatic and soil condition of bangladesh is suitable for the production of linseed crop. nematallahi and saeidi (2011) found significant differences in the response of several linseed genotypes to drought, with some being drought tolerant and others being 8 m.i. nazrul drought sensitive. in sylhet region, 164000 ha of land remain fallow during dry winter season because of varying degrees of existing soil moisture. as both sesame and linseed are considered as drought tolerant oil seed crops, they are presumed to be cultivated economically in the drought prone areas of bangladesh. therefore, the present investigation was carried out to assess the performance of linseed and sesame varieties under rainfed conditions for sylhet area. materials and methods the experiment was conducted at multi location testing (mlt) site, zokiganj during rabi and kharif-i seasons of 2014-15 and 2015-16 to select suitable linseed and sesame genotypes to fit into the fallow-fallow-t. (transplanted) aman rice cropping system under aez 20 in sylhet region of bangladesh. this is located in between 240 51' and 250 00' north latitudes and 92013' and 920 30' east longitudes and on an altitude of 10 meters. total cultivable land in the area is 11210 ha, which covered 70% single cropped, 63% double cropped and 88% triple cropped with cropping intensity 169%. the area is dominated by medium land with clay loam and loamy soils. major crops are paddy, mustard, sesame, linseed, potato, and winter vegetables. the dominant cropping patterns are fallow-fallow-t. aman rice, fallow-t. aus ricet. aman rice, vegetable-t. aus rice-t. aman rice and boro rice-fallow-fallow. the monthly temperature and rainfall for the experimental site are indicated in figures 1 and 2. the average climatic data of sylhet shows that the mean annual minimum temperature was 16.20 0c and the mean annual maximum temperature was 33.7 0c and the annual mean temperature was nearly 17.15 0c. fig. 1. minimum, maximum and mean temperature (0c) pattern in sylhet of bangladesh as indicated in figure 2, rainfall of the area is uni-modal, usually occurring during april to october, and total annual rainfall reached to 3372 mm; whereas in december no rain at all and lowest amount of rainfall occurs in january followed by february. however, in rest of the months total rainfall was ranged from 112 mm to just below 200 mm. rainfall increases gradually from the month of may and continued up to september. this experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. there were four different genotypes of linseed (var. bari tishi-1: nila, noakhalilocal, patuakhali-local and zakiganj-local) and sesame (t-6, bari til-2, bari til-3 and bari til-4) with seed rate 8.0 and 7.5 kg ha-1, respectively. the unit plot size was 10 m × 10 m. seeds were sown in broadcast method. 9 on-farm verification of linseed and sesame variety for fallow-fallow-t aman rice fig. 2. annual rainfall (mm) pattern in sylhet of bangladesh the seeds of linseed varieties were sown on 5-7 december and harvested on 10-15 march; on the contrary, sesame seeds were sown on 15-18 march and the crop harvested at full maturity on 12-15 june in 2014-15 and 2015-16, respectively. the seed yield was adjusted to 8% moisture content. the fertilizer nutrients npks (38-13-20-8 for linseed and 56-23-40-18 kg ha-1 for sesame) were applied in the form of urea, triple superphosphate (tsp), muriate of potash (mop) and gypsum, respectively (frg, 2012). all fertilizers were applied as a basal during final land preparation. plant protection measures and different intercultural operations were taken as and when necessary to raise healthy crops. the recorded data were statistically analyzed and mean values were separated by lsd test following gomez and gomez (1984). results and discussion crop calendar in study area the following seasonal activities were done during conducting the trial at farmers field (fig. 3). generally, aus rice transplanting was started in march and subsequent aman rice during the mid june to mid july and harvested within 2nd week of november. but in sylhet area, transplantation of aus rice being depended on rainfall and was done in early may. this delayed transplantation of aus rice, ultimately hampered the timely cultivation of subsequent t. aman rice and resulting delay sowing of rabi crops. to overcome this situation farmers cultivate local cultivars with less care and crop management practices. j f m a m j j a s o n d rabi kharif-1 kharif-2 rabi fallow fallow t. aman rice linseed sesame t. aman rice linseed fig. 3. seasonal activity calendar showing two crops in cropping pattern of study area crop: linseed it was revealed from the experimental results that among the different linseed varieties, the number of plant m-2 was non-significant; however, numerically the maximum number of plant m-2 was observed in bari tisi-1(nila) followed by genotype patuakhali-local. plant height was significantly influenced where the highest plant height was found in var. bari tishi-1 (64.85 cm) while the shortest (52.73 cm) in genotype noakhali-local. number of capsules in each 10 m.i. nazrul individual is an important yield contributing characters of linseed crop. the maximum number of capsules plant-1 was recorded in linseed genotype zakiganj-local (31.40) that was statistically followed by var. bari tisi-1 (21.28); while minimum number in patuakhali-local (19.13). the number of seeds capsule-1 was non-significant. among tested genotypes, zakiganj-local produced maximum 1000-seed weight (4.01 g) followed by noakhali-local (3.66 g) and the lowest in var. bari tishi-1 (3.57 g). zając (2005) reported that the productivity of linseed crop largely depends on its morphological characters associated with foliage. the maximum seed yield (1003 kg ha-1) was recorded in zakiganj-local that was statistically identical with noakhalilocal (820 kg ha-1). however, the lowest seed yield (782 kg ha-1) was found in patuakhali-local. table 1. seed yield and yield attributes of linseed varieties under on-farm trial during the rabi season of 2014-16; (pooled) variety plants m-2 (cm) plant height (cm) capsules plant-1 (no.) seeds capsule-1 (no.) 1000-seed weight (g) seed yield (kg ha-1) bari tishi-1 221 64.85 21.28 7.22 3.57 790 noakhali-local 191 49.55 20.63 7.37 3.66 820 patuakhali-local 207 52.73 19.13 7.53 3.64 782 zakiganj-local 201 50.80 31.40 7.73 4.01 1003 cv (%) 8.21 3.69 20.55 7.53 4.74 11.41 lsd (0.05) ns 4.17 9.6 ns 0.6 193.50 crop: sesame the result showed that plant height, capsules plant-1, seeds capsule-1, 1000-seed weight and seed yield were significantly influenced by different genotypes of sesame except plants m-2. it was noted from the experimental results that among the different sesame genotypes, the maximum plant height (101.10 cm) was found in the var. bari til-4 followed by bari til-2 (99.89 cm) and t-6 (99.83 cm). but, the var. bari til-4 produced the maximum number of capsules plant-1 (71.33) which was statistically similar to var. bari til-2 (68.67) and t-6, while var. bari til-3 produced the lowest number of capsules plant-1 (50.33). these results are in agreement with findings of tiwari et al. (2000) and kathiresan (2002). they reported that the number of capsules plant-1 varied significantly in different cultivars. number of seeds capsule1 was significantly influenced by varieties the var. bari til-4 produced the highest number of seeds capsule-1(70.33) followed by bari til-2 whereas var. bari til-3 produced the lowest number of seeds capsule-1 (53.00). these findings corroborated with the findings of nandita et al. (2009) and kathiresan (2002). variable effect of varieties on seeds capsule-1 in sesame plant was also reported by begum et al. it is stated that among the different sesame varieties, bari til-4 yielded maximum 1000-seed weight (3.12 g) followed by bari til-2 and t-6 where as var. bari til-3 produced lowest 1000-seed weight (2.81 g). the seed yield of sesame are generally resulted the cumulative effect of capsules plant-1, seeds capsule-1 and 1000-seed weight (rahman et al., 1995). it was observed that there was significant difference in seed yield plant-1 among the varieties. the var. bari til-4 produced the maximum seed yield plant-1 (1150 kg ha-1) followed by bari til-2 (1142 kg ha-1) while var. bari til-3 gave the lowest seed yield (840 kg ha-1). these results were supported by other researcher (khan et al., 2009). 11 on-farm verification of linseed and sesame variety for fallow-fallow-t aman rice table 2. seed yield and yield attributes of sesame varieties under on-farm trial during the kharif season of 2014-16 (pooled). variety plants m-2 (no.) plant height (cm) capsules plant-1 (no.) seeds capsule-1 (no.) 1000-seed weight (g) seed yield (kg ha-1) t-6 41.23 99.83 65.33 61.33 2.86 980 bari til-2 37.23 99.89 68.67 67.33 2.94 1142 bari til-3 44.57 95.76 50.33 53.00 2.81 840 bari til-4 40.57 101.10 71.33 70.33 3.12 1150 cv (%) 9.61 1.25 8.33 8.92 7.58 7.02 lsd (0.05) ns 2.57 10.21 11.69 0.44 144.00 conclusion the result showed that sesame var. bari til-4 produced higher seed yield followed by bari til-2 but in case of linseed var. zokiganj-local out-yielded the other local as well as bari developed linseed var. bari tishi-1. so, local variety of linseed should be given priority and yield could be enhanced by proper cultivation program. acknowledgements authors are gratefully acknowledged bangladesh agricultural research institute, gazipur and metrological department, sylhet for providing financial help and logistic support and weather data, respectively. thanks are also extended who contributed compile and editing of the manuscript. references anonymous. 1989. statistical year book of bangladesh. statistics division, ministry of planning, government of the people`s republic of bangladesh, dhaka, pp: 166. ariharan v. n., v. n. meena devi and p. n. prasad. 2015. linseed (linum isitatissimum l.) oils an alternative fuel source as biodiesel. res. j. pharmaceutical, biol. chem. sci. 6(1): 15271531 ashri. 1998. sesame breeding. plant breeding, revised edition, 16: 179-228. bedigan d. and j. r. harlan, 1986. evidence for the cultivation of sesame in the ancient world. econ. bot., 40: 137-154. begum, r., m. a. samad, m. r. amin, d. b. pandit, and m. a. jahan. 2001. effect of row spacing and population density on the growth and yield of sesame. bangladesh j. agril. sci., 28(2): 311-316. fernald, m. l. 1950. gray's manual of botany. eighth edition (corrected printing, r. c. rollins, 1970). d. van nostrand company, new york, ny. p.1632. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. 2nd edn. john wiley and sons. new york. p. 194. kathiresan, g. 2002. response of sesame (sesamum indicum l.) genotypes to levels of nutrients and spacing under different seasons. indian j. agron., 47: 537-540. 12 m.i. nazrul khan m. a. h., n. a. sultana, m. n. islam and m. hasanuzzaman. 2009. yield and yield contributing characters of sesame as affected by different management practices; am.eur. j. sci. res. 4 (3): 195-197. mchughen, a. 1990. "flax (linumusitatissimum l.): in vitro studies “biotechnology in agriculture and forestry”; 10: 502-514. mondal, r. i. and m. a. wahab. 2001. production technology of oil crops. oil seed research centre, bangladesh agricultural research institute, gazipur, bangladesh. p.73 nabi, m. n. and s. m. n. hoque. 2008. bio-diesel production from linseed oil and performance study of a diesel engine with diesel biodiesel. j. mech. eng. 39 (1): 40-44 nandita r., s. m. a. mamun and m. s. jahan. 2009. yield performance of sesame (sesamum indicum l.) varieties at varying levels of row spacing; res. j. agric. biol. sci., 5(5): 823827. nematallahi z, saeidi g. 2011. study of drought tolerance in some flax genotypes. iran j. water res. 25(1): 57–66. pathak, n., a. k. rai, r. kumari, k. v. bhat. 2014. value addition in sesame: a perspective on bioactive components for enhancing utility and profitability. phcog rev. 8: 147-55. rahman, m. m., t. s. hossen, a. a. a. muhsi, m. a. quadir and j. haider, 1995. seasonal variations in some physiological characters of sesame (sesamum indicum l.); bangladesh j. bot., 24: 47-51. tiwari, k. p., k. p. namdeo, k. n. namdeo, j. girish and g. jha. 2000. effect of nitrogen and sulphur on growth, yield and quality of sesame (sesamum indicum l.) varieties. res. crops, 1: 163-167. vereshagin, a. g. and g. v. novitskaya. 1965. the triglyceride composition of linseed oil. j. am. oil chem. soc., 42: 970-974. zając, t. 2005. assimilation area and yielding of linseed cultivars depending on sowing density and mineral treatment. acta agraria et silvestria series silvestris, 45: 65–76. microsoft word 2. baj-274_revised bangladesh agron. j. 2018, 21(1): 9-24 performance of wheat varieties under late plantinginduced heat stress condition m. m. rahman1, m. a. hasan2, m. f. chowdhury2, m. r. islam1 and m. s. rana1* 1department of crop physiology & ecology, hajee mohammad danesh sci. & technology university, dinajpur 2department of agronomy and agricultural extension, rajshahi university *corresponding author, e-mail: sohel0901084@gmail.com (received: 8 may 2017, accepted: 23 april 2018) keywords: wheat genotypes, late planting, heat stress tolerance and yield abstract the effect of late planting heat stress on physiological traits, yield attributes and yield of four wheat varieties (bari gom 25, bari gom 26, bari gom 28 and sourav) were tested in the study. november 30 sowing was considered as control and december 30 sowing as the late planting heat stress condition. wheat var. bari gom 25, bari gom 26 and bari gom 28 showed greater stability of flag leaf chl, higher level of proline in flag leaf and kernel and greater ability to keep the canopy cooler compared to sourav under late planting heat stress condition. more spike dry matter accumulation at peak, longer grain growth duration, better yield components such as number of grains spike-1, grain weight spike-1 and 1000-grain weight under heat stress contributed to better tolerance of bari gom 25, bari gom 26 and bari gom 28. the order of tolerance based on grain yield was bari gom 25 > bari gom 28 > bari gom 26 > sourav and the order of tolerance based on above ground biological yield was bari gom 28 > bari gom 26 > bari gom 25 > sourav. introduction wheat (triticum aestivum l.) is the world’s most widely cultivated food crop. it is the second important cereal crop after rice, and grown worldwide as the major sources of energy for human being. bangladesh covers an area of 0.43 million hectare for wheat cultivation with an annual production of about 1.30 million metric tons and average grain yield of 3.03 t ha-1 (anonymous, 2014). in bangladesh, about 60% of the wheat is cultivated at late sowing condition after harvesting the transplanted aman rice (badaruddin et al., 1994). late planting wheat exposed to high temperature (mean air temperature of >26oc) at reproductive stage causing reduction in yield and it is one of the major reasons of yield gap (hasan and ahmed, 2005). however, this problem will be further increased due to global warming. in this context, the temperature in bangladesh would be increased to 1.3oc and 2.6oc by the year 2030 and 2075, respectively with respect to the base year 1990. in spite of low yield of wheat due to post anthesis heat stress, cultivation of wheat cannot be avoided totally. because the irrigation dependent boro rice cultivation may need to be replaced in future by partially irrigated or non irrigated wheat cultivation. therefore, effort ought to be made to minimize the late sown yield reduction by screening or developing high temperature tolerant wheat genotypes/varieties or by ameliorating the effect of heat stress through agronomic strategies. different yield related characters were identified as contributing to heat tolerance in wheat. the most responsive yield component are number of grain spike-1, grains spikelet-1, grain weight, rate of grain filling, biomass at harvest (zong-hu and rajaram, 1994). in addition to these, other 10 rahman et al. physiological characters like chlorophyll (chl) content, stem reserves mobilization (sikder and paul, 2010), canopy temperature depression (sikder and paul, 2010) and stomata conductance (renolds et al., 1994) have been associated with performance of wheat under high temperature level. considering the above importance the present investigation was carried out to study the sensitivity of physiological traits resulting reduced grain yield of wheat in heat stressed environment and to observe the effect of late planting heat stress on yield contributing characters and yield of wheat. materials and methods the experiment was set up at the research farm of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur, bangladesh. the experiment was conducted in a splitplot design with three replications. the unit plot size was 2.5 m. x 2.4 m. november 30 sowing was considered as control and december 30 sowing as late planting heat stress condition. sowing times were placed in the main plots whereas four wheat varieties viz., bari gom 25, bari gom 26, bari gom 28 and sourav in the sub-plots. a fertilizer dose of 140-35-75-18-2-0.5 kg ha-1 n, p, k, s, zn and b was applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum and boric acid, respectively. after land preparation, full dose of p, k, s, zn, b and two-third of n were incorporated thoroughly into the soil as basal dose. the remaining amount of n was applied at 25 after seedlings emergence. seeds of four wheat varieties were sown on november 30, 2014 and december 30, 2014 in rows of 20 cm apart, at the rate of 120 kg ha-1. after sowing, light irrigation was given for uniform germination and other intercultural operations were done as per requirement. maximum, minimum and mean air temperature was recorded and days required to anthesis also calculated. spike dry matter accumulation at anthesis 80 main shoots were tagged from each plot. four tagged main shoot spikes were harvested at every 4th day beginning from anthesis to quantify spike dry matter accumulation pattern. collection of main shoot spike in all genotypes was continued up to 40 days after anthesis (daa) for both well watered and water deficit stress condition. the harvested spikes were kept in oven at 70oc for 72 hours. after oven drying, spikes were weighted with an analytical balance (and electronic balance model ek 300 i). determination of free proline content proline (pro) content of flag leaf and kernel at 16 daa of wheat genotypes grown in two growing conditions were estimated according to bates (1973) from a standard curve and calculated on a fresh weight basis as follows: moles pro g-1 of fresh plant material = {(g pro / ml x ml toluene) / 115.5 g /moles} / (g sample/5) determination of chlorophyll content total chl content of the flag leaf at 8 and 24 days after anthesis was estimated according to witham et al. (1986) using following formula total chl (mg g-1 fw) = [20.2 (d645) + 8.02 (d663)] x [v/ (1000 x w)] (where, v = volume of 80% aqueous acetone (ml), w = weight of fresh leaf (g), d645 = absorbance at 645nm wave length and d663 = absorbance at 663nm wavelength) determination of leaf relative water content (rwc) performance of wheat varieties under late planting 11 relative water content in flag leaf was determined at 16 daa from the equation of schonfeld et al. (1988). rwc (%) = {(fresh weight – dry weight)/( turgid weight dry weight)} x 100 canopy temperature depression (ctd) the hand held infra-red thermometer (model: crop track item no. 2955l-spectrum tecnologies, inc.) was used to measure the ctd at 8 and 24 daa during noon period under bright sunlight and less wind conditions. agronomical traits plant height, spike length (excluding awn), number of spikes m-2, number of grains spike-1, grain dry weight spike-1, thousand grain weights, grain yield and above ground biological yield of wheat genotypes were taken properly. grain and above ground biological yield were adjusted to 12% moisture content. stress susceptibility index (ssi) stress susceptibility index (ssi) was calculated for grain yield using following formula ssi = (1y/yp) / (1x/xp) (where, y = grain yield of genotype in a stress environment, yp= grain yield of genotype in a stress-free environment, x = mean y of all genotypes and xp= mean yp of all genotypes all the collected data were analyzed by partitioning the total variance with the help of computer by using mstat program. the treatment means were compared using duncun’s multiple range test (dmrt) at p5% level. correlation analysis was done using mstat program. result and discussion maximum, minimum and mean air temperature during the growing period maximum, minimum and mean air temperature recorded from the experimental site during 16 january to 16 april 2015 is presented in fig. 1. from this figure it is revealed that the wheat varieties sown on november 30 experienced less than 26oc throughout their whole reproductive growth phase was considered as control and wheat varieties sown on december 30 experienced more than 26oc considered as late planting heat stress. 12 rahman et al. fig. 1. maximum, minimum and mean air temperature from 16 january to 16 april 2015 showing the period of anthesis and maturity of normal and late planting wheat. phenological parameters due to late planting heat stress number of days required to anthesis was reduced but it was not influenced significantly by the interaction effect of wheat varieties and temperature regimes (table 1). under late planting heat stress condition, all the wheat varieties required shorter time (63-64 days) to attain anthesis compared to control (73-74 days). table 1. effect of late planting heat stress on days required to attain anthesis and physiological maturity of different wheat varieties wheat varieties temperature regimes days to anthesis days to physiological maturity number of days early in days over control number of days early in days over control bari gom 25 control 73 113 a heat stress 64 9 104 a 7 bari gom 26 control 73 113 a heat stress 63 9 95 b 18 bari gom 28 control 73 109 a heat stress 63 10 95 b 14 sourav control 74 114 a heat stress 63 11 91 c 23 level of significance ns * cv (%) 1.42 3.50 in a column, values followed by similar letter (s) did not differ significantly by dmrt at p5%. asterisk represents level of significance. wheat varieties and temperature regimes interacted significantly to influence the number of days required to attain physiological maturity (table 1). under late planting heat stress condition, all the wheat varieties required shorter time (91-104 days) to attain physiological 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 days t em pe ra tu re ( o c ) minimum maximum mean anthesis (normal) anthesis (heat) maturity (normal) maturity (heat) performance of wheat varieties under late planting 13 maturity compared to control (109-114 days). sourav required maximum days (114 days) to attain physiological maturity under control and it attained at physiological maturity 23 days earlier under heat stress condition, bari gom 25 required 113 days to and 7 days earlier under heat stress condition, bari gom 26 required 113 days under control and 18 days earlier under heat stress condition whereas bari gom 28 required minimum days (109 days) under control and 14 days earlier under heat stress condition. the phonological stages of wheat were influenced by the environment during growing period. sikder (2009) observed that the number of days for attaining anthesis, grain filling and maturity stages were higher for normal sowing condition compared to late sowing and also reported that the heat tolerant cultivars required higher number of days for attaining different phenological stages than the heat sensitive cultivars. physiological traits flag leaf chlorophyll content flag leaf chl content at 8 days after anthesis (daa) was not significantly influenced by the interaction effect of wheat varieties and temperature regimes but flag leaf chl content at 24 days after anthesis was significantly influenced (table 2). due to heat stress, all the wheat varieties showed lower flag leaf chl content (0.97-1.28 mg chl g-1 fw) compared to control (1.29-1.49 mg chl g-1fw). due to heat stress, flag leaf chl was reduced by 22, 6, 16 and 24% in bari gom 25, bari gom 26, bari gom 28 and in sourav. in the present study flag leaf chl content was reduced in all wheat varieties at 24 days after anthesis. dhyani et al. (2013) and almeselmani and deshmukh (2012) also found that chl content was reduced in wheat due to heat stress. possible reasons of reduction in chl content due to high temperature stress may be increased activity of peroxidase (jiang et al., 2007), increase in chlorophyll breakdown (thomas et al., 1980) and reduction in chl biosynthesis. the present showed that heat tolerant cultivars retain higher amount of chl. 14 rahman et al. table 2. effect of late planting heat stress on different physiological traits of four wheat varieties wheat varieties temperature regimes flag leaf chl content proline content ctd at 8 daa at 24 daa flag leaf kernel at 8 daa at 24 daa mg g-1 fw % change over control mg g-1 fw % change over control µmol g-1 fw % change over control µmol g-1 fw % change over control oc % change over control oc % change over control bari gom 25 control 1.62 1.49 a 8.10 b 7.33 b 4.17 3.72 a heat stress 1.65 2 1.15 c -22 10.46 a 29 11.05 a 50 2.75 -34 1.58 b 57 bari gom 26 control 1.78 1.37 ab 6.75 bc 6.75 b 4.20 3.93 a heat stress 1.54 -13 1.28 bc -6 8.07 b 19 10.51 a 55 2.74 -34 1.78 b 54 bari gom 28 control 1.78 1.41 ab 7.81 b 6.25 b 4.47 3.93 a heat stress 1.75 -2 1.18 c -16 11.34 a 45 10.76 a 72 2.72 -39 1.58 b -59 sourav control 1.67 1.29 bc 5.62 c 6.82 b 4.37 3.90 a heat stress 1.78 6 0.97 d -24 5.37 c -4 6.65 b -2 2.75 -37 1.05 c -73 level of significance ns ** ** ** ns * cv (%) 11.34 4.45 8.60 12.41 5.65 8.16 ctd = canopy temperature depression, daa= days after anthesis in a column, values followed by similar letter(s) did not differ significantly by dmrt at p0.05 asterisk represents level of significance performance of wheat varieties under late planting 15 flag leaf and kernel proline content wheat varieties and temperature regimes interacted significantly to influence flag leaf and kernel pro content at 16 days after anthesis (table 2). on november 30 sowing, bari gom 25 contained the highest amount of pro in flag leaf (8.10 mole g-1 fw) followed by bari gom 28 (7.81 mole g-1 fw) and bari gom 26 (6.75 mole g-1 fw) while sourav contained the lowest amount of pro in flag leaf (5.62 mole g-1 fw). under late planting heat stress condition, flag leaf pro was increased by 29,19, 45 in bari gom 25, bari gom 26 and bari gom 28 whereas the flag leaf pro was reduced by 4.45% in sourav compared to control (november 30 sowing). under control, bari gom 25 contained the highest amount of pro in kernel (7.33 mole g-1 fw) which was followed by sourav (6.82 mole g-1 fw) and bari gom 26 (6.75 mole g-1 fw) while bari gom 28 contained the lowest amount of pro in kernel (6.25 mole g-1 fw). under late planting heat stress condition, kernel pro was increased by 50% in bari gom 25, 55% in bari gom 26 and 72% in bari gom 28 whereas the kernel pro was reduced by 2% in sourav compared to control (november 30 sowing). increased pro synthesis in heat stressed environment may be due to loss of feedback regulation in pro biosynthetic pathway (boggess and stewart 1980). canopy temperature depression (ctd) canopy temperature depression at 8 days after anthesis was not influenced significantly by the interaction effect of wheat varieties and temperature regimes but at 24 days after anthesis was influenced significantly (table 2). at 8 days after anthesis, all the wheat varieties maintained higher canopy temperature depression (4.17 to 4.47oc) on november 30 sowing (control) compared to heat stress condition (2.72 to 2.75oc) i.e. all the wheat varieties maintained cooler canopy on november 30 compared to heat stress condition. at 24 days after anthesis, all the wheat genotypes maintained higher ctd (3.72 to 3.93oc) under control compared to that (1.05 to 1.78oc) under heat stress condition. ctd was reduced by 57% in bari gom 25, 54% in bari gom 26, 59% in bari gom 28 and 73% in sourav. in the present study, it was observed that wheat variety bari gom 25, bari gom 26 and bari gom 28 recorded higher ctd under late planting heat stress condition than sourav. that indicated that three varieties had greater ability to maintain canopy cooler than sourav. this performance in ctd of different cultivars was reflected to their yield performance. spike dry matter accumulation a typical sigmoid pattern of dry matter accumulation in spike were found in all wheat varieties both under optimum sowing and late plating heat stress condition (fig. 2). under control condition, the spike dry weight was observed to be increased up to 2.38 g at 40 daa in bari gom 25, 2.77 g at 40 daa in bari gom 26, 2.55 g at 36 daa in bari gom 28 and 2.65 g at 40 daa in sourav and decline thereafter slowly. under heat stress condition, maximum dry matter accumulation in spike was reduced in all wheat varieties and days required to attain maximum dry weight were reduced in all genotypes except bari gom 25. the reduction in maximum spike dry weight was 5.46% in bari gom 25, 5.56% in bari gom 26, 5.10% in bari gom 28 and 13.96% in sourav. number of days required to attain maximum spike dry weight which indicates grain growth duration were reduced 8 days in bari gom 26, 4 days in bari gom 28 and 12 days in sourav whereas no reduction was found in bari gom 25 (fig. 2 and 3). the declining tendency in spike dry weight after attaining the peak could be due to respiratory loss of kernel after physiological maturity. hasan and ahmed (2005) and roy et al. (2013) also found post anthesis heat stress resulted in reduced dry matter accumulation at peak and reduced grain filling period but reductions were lower in heat tolerant genotypes than those in sensitive wheat genotypes. 16 rahman et al. fig. 2. spike dry matter accumulation in different wheat varieties at different days after anthesis as influenced by late planting heat stress. fig. 3. effect of late planting heat stress on grain growth duration (days) of different wheat varieties. grain dry weight spike-1 grain dry weight spike-1 was influenced significantly by the interaction effect of wheat varieties and temperature regimes (fig. 4). on november 30 sowing, bari gom 28 and sourav 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 sp ik e dr y w ei gh t (g ) days after anthesis bari gom 25 control heat stress 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 sp ik e dr y w ei gh t (g ) days after anthesis bari gom 26 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 sp ik e dr y w ei gh t (g ) days after anthesis bari gom 28 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 sp ik e dr y w ei gh t (g ) days after anthesis sourav a a b aa c c d 0 5 10 15 20 25 30 35 40 45 bari gom 25 bari gom 26 bari gom 28 sourav gr ai n gr ow th d ur at io n (d ay s) wheat varieties control heat performance of wheat varieties under late planting 17 provided the highest grain dry weight spike-1 which was followed by bari gom 26 whereas bari gom 25 provided the lowest grain dry weight spike-1. due to late planting heat stress, grain dry weight spike-1 was reduced in al wheat varieties but the degree of reduction in grain dry weight spike-1 was different in different varieties. grain dry weight spike-1 was reduced by 1.74% in bari gom 25, 7.50% in bari gom 26, 9.09% in bari gom 28 and 15.31% in sourav due to heat stress compared to control (november 30 sowing). hasan and ahmed (2005) and roy et al. (2013) also found post anthesis heat stress resulted in reduced grain dry weight spike-1 but reductions were lower in heat tolerant genotypes than those in sensitive wheat genotypes. reduction in grain dry weight spike-1 in different magnitude in different wheat genotypes under heat stress might be due to variation in grain growth rate (hasan and ahmed, 2005 and hasan 2009), grain growth duration (hasan and ahmed, 2005 and hasan, 2009) and stem reserve utilization (roy et al., 2013). fig. 4. effect of late planting heat stress on grain dry weight spike-1 of different wheat varieties. agronomic traits plant height and spike length at harvest plant height and spike length at harvest were not influenced significantly by the combined effect of wheat varieties and temperature regimes but all the wheat varieties provided shorter plant and spike under optimum sowing compared to late planting heat stress condition except spike length in bari gom 26 (table 3).due to late planting heat stress, the development of plant organs, photosynthesis rate and transfer of assimilate from source (sial et al., 2005, hasan, 2009) were remarkably affected, which was reflected by overall shortening of plant height. number of spikes m-2 the combined effect of wheat varieties and temperature regimes on number of spikes m-2 was significant (table 3). on november sowing (control), the highest number of spikes per m-2 was observed in bari gom 28 (351) which was followed by sourav (308) and bari gom 26 (297) whereas, the lowest number of spikes m-2 was observed in bari gom 25 (295). due to the effect of heat stress number of spikes m-2 was reduced in all wheat varieties. but the degree of reduction was different in different varieties. spikes m-2 was reduced by 2% in bari gom 25, 3% in bari gom 26, 1% in bari gom 28 and 20% in sourav due to heat stress compared to c a a a c b b c 0.0 0.5 1.0 1.5 2.0 2.5 3.0 bari gom 25 bari gom 26 bari gom 28 sourav g ra in d ry w ei gh t ( g sp ik e1) wheat varieties control heat 18 rahman et al. control (november 30 sowing). sial et al. (2005), roy et al. (2013) and hasan et al. (2007) also found reduced number of ears m-2 in heat stressed environment. number of grains spike-1 number of grains spike-1 was significantly influenced by the combined effect of wheat varieties and temperature regimes (table 3). on november sowing (control), the highest number of grains spike-1 was observed in bari gom 26 (53) which was followed by bari gom 28 (50) and sourav (49) and whereas the lowest number grains spike-1 was observed in bari gom 25 (38). due to the effect of heat stress number of grains spike-1 was reduced in different magnitude in different varieties. the reduction was 13% in bari gom 25, 1% in bari gom 26, 6% in bari gom 28 and 18% in sourav. significant variation among different wheat genotypes in the reduction in number of grain ear-1 under heat stress was found by hasan et al. (2007), sial et al. (2005) and radhika and thind (2014). 1000-grain weight the combined effect of wheat varieties and temperature regimes on thousand grain weight was found significant (table 3). on november sowing (control), the maximum thousand grain weight was recorded in bari gom 25 (50.93 g) which was followed by bari gom 28 (43.80 g) and bari gom 26 (42.97) whereas the lowest in sourav (40.70 g). due to late planting heat stress thousand grain weights was reduced in all wheat varieties except in bari gom 26 but the degree of reduction was different in different varieties. thousand grain weights were reduced by 4% in bari gom 25, 2% in bari gom 28 and 9% in sourav. on the other hand thousand grain weigh was increased somewhat (0.09%) due to heat stress in bari gom 26. significant variation in reduction in grain size under heat stress among different wheat genotypes was also observed by sial et al. (2005), dhyani et al. (2013) and hasan and ahmed (2005). greater grain size in heat tolerant genotypes due to longer duration of rapid grain growth rate (hasan and ahmed 2005). performance of wheat varieties under late planting 19 table 3. effect of late planting heat stress on agronomical traits of wheat varieties wheat varieties tempera ture regimes plant height spike length spike m-2 grains spike-1 1000-grain weight grain yield above ground biological yield cm % change over control cm % change over control number % change over control number % change over control g % change over control tha-1 % change over control tha-1 % change over control bari gom 25 control 107.9 11.4 295 b 38 d 50.93 a 3.12 a 9.32 a heat stress 97.0 -10 10.6 -7 288 b -2 33 e -13 48.83 b 4 2.65 b -15 6.74 bc -27 bari gom 26 control 102.8 10.1 297 b 53 a 42.97 c 3.49 a 9.23 a heat stress 96.0 -6 10.4 3 288 b -3 52 ab -2 42.93 c 0.09 2.71 b -22 6.75 bc -26 bari gom 28 control 103.0 10.7 351 a 50 ac 43.80 c 3.26 a 8.94 a heat stress 97.1 -5 9.2 -14 346 a -1 47 c -6 42.53 cd -2. 2.67 b -18 7.51 b -15 sourav control 103.6 10.9 308 b 49 bc 40.70 c 3.47 a 9.53 a heat stress 99.9 -3 10.5 -3 246 c -20 40 d -18 36.77 e 9 2.16 c -37 5.94 c -37 level of significance ns ns ** ** ** ** ** cv (%) 4.94 2.84 3.22 3.17 1.90 4.84 5.09 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p5% asterisk represents level of significance 20 rahman et al. grain yield the combined effect of wheat varieties and temperature regimes on grain yield was found significant. (table 3). on november sowing (control), the maximum grain yield was recorded in bari gom 26 (3.49 t ha-1) which was followed by sourav (3.47 t ha-1) and bari gom 28 (3.26 t ha-1) whereas the lowest grain yield was found in bari gom 25 (3.12 t ha-1). due to late planting, heat stress grain yield was reduced in all wheat varieties but the degree of reduction was different in different varieties. grain yield was reduced by 15% in bari gom 25, 22% in bari gom 26, 18% in bari gom 26 and 37% in sourav. significant variation in reduction in grain yield in different wheat genotypes due to heat stress was also found by baloch et al. (2012), khan and kabir (2014), laghari et al. (2012), dhyani et al. (2013), radhika and thind (2014), hasan et al. (2007) and roy et al. (2013). they found that better performance of all the yield parameters such as number of spike m-2, number of grains spike-1, grain weight spike-1 and grain size had contribution to better grain yield of heat tolerant wheat genotypes. above ground biological yield above ground biological yield was influenced significantly by the combined effect of wheat varieties and temperature regimes (table 3). on november sowing (control), the highest above ground biological yield was recorded in sourav (9.53 t ha-1) which was followed by bari gom 25 (9.32 t ha-1) and bari gom 26 (9.23 t ha-1) whereas the lowest above ground biological yield was found in bari gom 28 (8.94 t ha-1). due to late planting heat stress, above ground biological yield was reduced in all wheat varieties but the degree of reduction was different in different varieties. the reduction was 27% in bari gom 25, 26% in bari gom 26, 15% in bari gom 28 and 37% in sourav. the reduced above ground biological yield in wheat under heat stress was due to the reduced grain and straw yield. khan and kabir (2014), hasan and ahmed (2005) and roy et al. (2013) also reported reduced biological yield under high temperature. correlation analysis between relative performances of various parameters correlation analysis between relative performances of various parameters studied in this investigation is presented in table 4. relative grain yield maintained a significant positive correlation with relative flag leaf chl content at 24 daa (0.43*), relative flag leaf pro content at 16 daa (0.89**), relative kernel pro content at 16 daa (0.91**), relative canopy temperature depression at 24 daa (0.88**), relative spikes m-2 (0.97**), relative grains spike-1 (0.57**), relative thousand grain weight (0.77**), relative grain dry weight spike-1 (0.90**) and above ground biological yield (0.77**). nagrajan and rane (2002) reported a significant correlation between grain weight spike-1 and ctd in general. hasan and ahmed (2005) was found significant positive correlation between pro level and grain yield of wheat under heat stress environment. performance of wheat varieties under late planting 21 table 4. relationship among the relative performances of physiological traits, grain yield and straw yield of different wheat varieties relative flag leaf chl content at 24 daa relative flag leaf pro content at 16 daa relative kernel pro content at 16 daa relative canopy temperature depression at24 daa relative spikes m-2 relative grains spike-1 relative thousand grain weight relative grain dry weight spike-1 relative grain yield relative above ground biological yield relative flag leaf chl content at 24 daa relative flag leaf pro content at 16 daa 0.57** relative kernel pro content at 16 daa 0.75** 0.95** relative canopy temperature depression at 24 daa 0.67** 0.71** 0.88** relative spikes m-2 0.63** 0.60** 0.97** 0.94** relative grains spike-1 0.97** 0.60** 0.81** 0.82** 0.75** relative thousand grain weight 0.74** 0.67** 0.87** 0.97** 0.88** 0.94** relative grain dry weight spike-1 0.15ns 0.60** 0.67** 0.83** 0.81** 0.37* 0.66** relative grain yield 0.43* 0.89** 0.91** 0.88** 0.97** 0.57** 0.77** 0.90** relative above ground biological yield 0.73** 0.96** 0.93** 0.65** 0.84** 0.70** 0.68** 0.41* 0.77** 22 rahman et al. stress susceptible index (ssi) fig. 5 shows stress susceptibility index of different wheat varieties based on grain yield. wheat var. bari gom 25 showed the lowest heat stress susceptibility index that was followed by bari gom 28 and bari gom 26. sourav showed the highest heat stress susceptibility index. these stress susceptibility index values indicated that bari gom 25, bari gom 26 and bari gom 28 were heat tolerant varieties and sourav was heat susceptible variety. fig. 6 shows stress susceptibility index of different wheat varieties based on above ground biological yield. bari gom 28 showed the lowest heat stress susceptibility index that was followed by bari gom 26 and bari gom 25. sourav showed the highest heat stress susceptibility index. these stress susceptibility index values indicated that bari gom 25, bari gom 26 and bari gom 28 were more tolerant varieties than sourav. hossain et al. (2013), agrawal et al. (2014), hasan and ahmed (2005) and rasal et al. (2006) found that the heat tolerant genotypes showed lower susceptibility index than the heat sensitive genotype. fig. 5. stress susceptibility index of different wheat varieties based on grain yield. fig. 6. stress susceptibility index of different wheat varieties based on above ground biological yield. conclusion d b c a 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 bari gom 25 bari gom 26 bari gom 28 sourav st re ss su sc ep tib ili ty in de x bs ed on gr ai n yi el d wheat varieties b b c a 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 bari gom 25 bari gom 26 bari gom 28 sourav st re ss su sc ep tib ili ty in de x bs ed on ab ov e gr ou nd b io lo gi ca l y ie ld wheat varieties performance of wheat varieties under late planting 23 from the overall results it may be concluded that wheat var. bari gom 25, bari gom 26 and bari gom 28 showed greater stability in chl and higher level of pro in flag leaf and kernel as well as greater ability to keep the canopy cooler compared to sourav under late planting heat stress condition. greater spike dry matter accumulation at peak, longer grain growth duration, better yield components such as spikes m-2, grains spike-1, grain weight spike-1 and 1000-grain weight under heat stress contributed to better tolerance of bari gom 25, bari gom 26 and bari gom 28. the order of tolerance based on grain yield was bari gom 25 > bari gom 28 > bari gom 26 >sourav and the order of tolerance based on above ground biological yield was bari gom 28 > bari gom 26 > bari gom 25 >sourav. references agrawal, a. p., d. pandey and d. pandey. 2014. variation parameters for heat tolerance index of wheat. j. wheat res. 6(1):37-40. almeselmani, m. and p. s. deshmukh. 2012. effect of high temperature stress on physiological and yield parameters of some wheat genotypes recommended for irrigated and rainfed condition. jordan j. agri. sci. 8 (1): 66-77. anonymous. 2014. yearbook of agricultural statistics of bangladesh, bangladesh bureau of statistics, ministry of planning, government of the people’s republic of bangladesh. badaruddin, m., d. a. sauders, a. b. siddique, m. a. hossain, m. o. ahmed, m. m. rahman and s. parveen. 1994. determining yield constraints for wheat production in bangaldesh. p. 265271. in d. a. saunders and g. p. hettel (eds.) wheat in heat stressed environments; irrigated, dry areas and rice-wheat farming systems. cimmyt, mexico, d. f. baloch, m. s., m. a. nadim, m. zubair, i. u. awan, e. a. khan and s. ali. 2012. evaluation of wheat under normal and late sowing conditions. pak. j. bot. 44(5): 1727-1732 bates, l. s. 1973. rapid determination of free proline for water-stress studies. plant soil 39:205-207. bogess, s. f. and c. r. stewart. 1980. the relationship between water stress induced proline accumulation and inhibition of protein synthesis in tobacco leaves. plant sci. lett17:245252. dhyani, k., m. w. ansari, y. r. rao, r. s. verma, a. shukla and n.tuteja. 2013. comparative physiological response of wheat genotypes under terminal heat stress. plant signaling & behavior 8(6): 1-6. hasan, m. a. 2009. physiology of sustaining wheat yield under late planting heat stressed environment. ph. d thesis, department of crop botany, bsmrau, gazipur. hasan, m. a. and j. u. ahmed. 2005. kernel growth physiology of wheat under late planting heat stress. j. natn. sci. foundation sri lanka 33(3):193-204. hasan, m. a., j. u. ahmed, m. m. bahadur, m. m. haque and s. sikder. 2007. effect of late planting stress on membrane thermostability, proline content and heat susceptibility index of different wheat cultivars. j. natn. sci. foundation sri lanka 35(2):109-117. hossain, a., m. a. z. sarker, m. saifuzzaman, j. a. teixeira da silva, m. v. lozovskaya, m. m. akhter. 2013. evaluation of growth, yield, relative performance and heat susceptibility of eight wheat (triticum aestivum l.) genotypes grown under heat stress. int. j. plant prod.7 (3): 615-636. jiang, c., y. yin, x. liu and z. wang. 2007. response of flag leaf lipid per oxidation and protective enzyme activity of wheat cultivars with different heat tolerant to high temperature stress after anthesis. acta agron. sin. 3(1): 143-148. keeling, p. l., r. banisadr, l. barone, b. p. wasserman and g. w. singletary. 1994. effect of temperature on enzymes in the pathway of starch biosynthesis in developing wheat and maize grain. aust. j. plant physiol. 21: 807-827. 24 rahman et al. khan, a. a. and m. r. kabir. 2014. evaluation of spring wheat genotypes (triticum aestivum l.) for heat stress tolerance using different stress tolerance indices. cercetari agronomice in moldova. 47(4): 49-63. laghari, k. a., m. a. sial and m. a. arain. 2012. effect of high temperature stress on grain yield and yield components of wheat (triticum aestivum l.). sci. technol dev. 31 (2): 83-90. nagrajan, s. and j. rane. 2002. physiological traits associated with yield performance of spring wheat under late sown conditions. indian j. agric. sci. 72(3): 135-140. radhika, and s. k. thind. 2014. various agronomic traits as affected by sowing date mediated heat stress conditions. int. j. agri. crop sci. 7 (2): 76-78. rasal, p. n., v. n. gavhane, d. v. kusalkar, a. b. gosavi and g. n. shirpurkar. 2006. effect of high temperature stress on heat susceptibility index and thermal requirement of bread wheat genotypes. res. crops. 7(3): 811-813. renolds, m. p., r. p. singh, a. ibrahim, o. a. a. ageeb, a. larquesaavedra and j. s. quick. 1998. evaluating physiological traits to complement empirical selection for wheat in warm environments. euphytica, 100: 84-95. reynolds, m. p., m. balota, m. i. b. delgado, i. amani, and r.a. fischer. 1994. physiological and morphological traits associated with spring wheat yield under hot, irrigated conditions. aust. j. plant physiol. 21:717-30. roy, t. k., m. h. r. hafiz, m. r. islam, m. a. hasan and m. n. siddiqui. 2013. late planting heat stress on ear growth physiology of wheat. int. j. biol. 3(11): 8-19. schonfeld, m. a., r. c. johnson, b. f. carver and d. w. mornhinweg. 1988. water relations in winter wheat as drought resistance indicator. crop. sci. 28: 526-531. sial, m. a., m. a. arain, k. shamadad, m. h. naqvi, m. u. dahot and n. a. nizamani. 2005. yield and quality parameters of wheat genotypes as affected by sowing dates and high temperature stress. pak j. bot.. 37(3): 575-584. sikder, s. 2009. accumulation heat unit and phenology of wheat cultivars as influenced by late sowing heat stress condition. agril. rural dev. 7(1&2):57-64. sikder, s. and n. k. paul. 2010. study of influence of temperature regimes on germination characteristics and seed reserves mobilization in wheat. afr. j. plant sci. 4(10): 401-408. thomas, h., j. l. stoddart and j. f. potter. 1980. temperature responses of membrane associated activities from spring and winter oats. plant cell environ. 3: 271-277. witham, h., d. f. blades and r. h. devin. 1986. exercise in plant physiology (2nd edition), pws publishers, boston, usa, pp. 128-131. zhong-hu, h. and s. rajaram (1994): differential responses of bread wheat characters to high temperature. euphytica. 72: 197–203. bangladesh agron. j. 2019, 22(2): 91-102 screening of advanced aromatic rice lines using morphological and physico-chemical characteristics s. paul1, p.k. biswas2, m.s. islam2,s.s. siddique3, b.j. shirazy3and m.s. kobir3 1ex-ms student, sau & s.o., bari, rars, jashore; 2professor, dept. of agronomy, sau; 3scientist, bari, rars, jashore corresponding e-mail: suchanapaul.sau@gmail.com (received: 12 january 2020, accepted: 25 february 2020) keywords: aromatic rice, morphological, physic-chemical characteristics, yield abstract short-statured and lodging resistant rice plants with long to medium slender grain are the expected criteria for aromatic rice. however, most of the aromatic rice varieties in bangladesh do not meet the expected criteria. therefore, this study was undertaken to detect short-statured rice plants with aromatic and long to medium slender grain where twelve advanced rice lines (derived from the local rice germplasm) with a local check kataribhog were evaluated. all the genotypes demonstrated significant variation for different parameters such as plant height at harvest, yield per hectare, grain length, grain size, grain shape, and aroma. at harvest, the shortest plant height was obtained from sau adl11 (107.09cm), and it was statistically similar to sau adl4 (111.68cm) and sau adl5 (111.89cm). however, the plant height of check variety kataribhog was 167.17cm. the highest grain yield per hectare was found in sau adl5 (4.79 tha-1), where it was 2.71 tha-1 in kataribhog. besides, the grain yield of shorter genotypes sau adl4 and sau adl11 was 3.47 t ha-1 and 3.84 t ha-1 , respectively. the sau adl1 provided the highest kernel length (7.31mm), and the lowest kernel length (4.87 mm) was recorded in the check. kernel length of short-statured genotypes ranged from 7.01 mm to 6.57 mm. kernel size of all evaluated genotypes was long to medium; whereas, it was short for kataribhog. kernel shape of these short-statured genotypes was slender to medium. in case of aroma, sau adl3, sau adl5, sau adl7, sau adl9, sau adl10, and sau adl11 were moderately aromatic, and other genotypes were non-aromatic. however, kataribhog was strongly aromatic. finally, sau adl5 and sau adl11 were evaluated as important germplasms in respect of different characters such as shortstatured plant, long to medium slender grain, and aroma. these two lines could be potential inbreed aromatic rice genotypes for bangladesh. introduction aromatic rice cultivars are a special group of rice genotypes (aljumaili et al., 2018), characterized by their qualities like nut-like aroma, cooking, eating and/or super-fine grained (roy et al., 2016). this group of rice is very popular throughout asia and has gained wider acceptance in europe, australia, the middle east and the united states of america (sakthivel et al., 2009). according to giraud (2013), the international trade market is covered by two aromatic rice varieties namely basmati (from the indian subcontinent), and jasmine rice (from thailand) because of its’ premium long grain and aroma. according to kaul (1970), the premium grain was determined by grain length (> 6.0 mm), and length: breadth ratio (l/b 2.5mm to 3mm). therefore, rice grains with these qualities can be defined as premium quality grain. several authors (krishna et al., 2018 and louis et al., 2005) mentioned that the consumers' demand has significantly increased for quality grain aromatic rice. therefore, research 102 paul et al. regarding aromatic rice development increases in different rice-growing countries to fulfill the consumers’ demand. in bangladesh, the cultivated aromatic rice genotypes are mostly traditional or native types (islam et al., 2018). the major drawback is that these native aromatic rice germplasms are low yielding per hectare (islam et al., 2018). long-statured and lodging susceptible nature were identified as the reasons behind the low yield of native cultivars (mia et al.,2012).moreover, most of these cultivars produced short bold to medium bold grain and could not meet the criteria of premium quality grain (islam et al., 2013). therefore, short-statured, quality grain aromatic rice is important to develop or evaluate. according to khalid et al. (2010) morphological traits were considered effective in evaluation, as they were economic and feasible. moreover, morphological traits can be easily transmitted to the next generation through conventional breeding (islam et al., 2016). apart from morphological traits, some other qualities such as milling, cooking, and eating can also be considered for the evaluation of aromatic rice germplasm (juliano and bechtel, 1985). bangladesh has a stock of above 8,000 rice germplasm of which nearly 100 are aromatic (khalequezzaman et al., 2012). these traditional aromatic rice germplasm are great reservoirs of the valuable gene pool (ahmed et al., 2016). however, many of these germplasm have already been lost from bangladesh and some of them are still on the verge of extinction (ahmed et al., 2010). moreover, information regarding the characterization, genetic diversity, and quality of different local rice germplasm in bangladesh is limited (islam et al., 2018). thus, it is important to conserve these germplasm. meanwhile, it is necessary to characterize and evaluate these local rice germplasm both morphologically and physico-chemically. therefore, in this study, twelve advanced lines (derived from the local rice germplasm of bangladesh) were evaluated to find out short-statured, quality grained aromatic rice. materials and methods collection of seed seeds of local aromatic aman rice (grown in july to december) genotypes were preserved in the department of agronomy of sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka1207. then, twelve advanced lines were selected from the local genotypes through various field observations by the department of agronomy of sher-e-bangla agricultural university. the selected advance lines were named as sau adl (sher-e-bangla agricultural university agronomy department line) having chronological numerical as (i) sau adl1, (ii) sau adl2, (iii) sau adl3, (iv) sau adl4, (v) sau adl5, (vi) sau adl6, (vii) sau adl7, (viii) sau adl8, (ix) sau adl9, (x) sau adl10, (xi) sau adl11 and (xii) sau adl12. kataribhog was collected from bangladesh rice research institute, gazipur, bangladesh and used as the check variety throughout the entire evaluation process. experimental design and management practice the experiment was laid out in randomized completely block design (rcbd) with three replications and there were thirteen rice genotypes as treatment. sprouted seeds were sown in seedbed on and transplanted on the main field. the plot size was 6 m2, with spacing 25 cm 15 cm; 8 rows plot-1, 20 hills row-1, and one seedling hill-1. the experimental area was fertilized with 120, 80, 80 and 20 kg ha-1 of n, p2o5, k2o and s applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum respectively. the entire amounts of tsp, mp, and gypsum were applied as basal dose at final land preparation. the urea was top-dressed in three equal installments. all the plots were irrigated depending on rainfall to maintain the flood condition. all the plots were dried 7 days before harvesting. screening of advanced aromatic rice lines using 101 evaluation of plant growth and yield contributing characters the crop was considered mature after 80 percent grain became yellow color. harvesting was started manually at 106 days and continued up to 138 days according to the maturity of the individual lines. ten hills were selected randomly per plot for evaluation of different growth parameters such as plant height (cm) at harvest, the number of tillers hill-1 at harvest, effective tillers hill-1, panicle length (basal node of the rachis to apex), total grains panicle-1, thousand grain weight (g). to determine the fertile spikelet per panicle (%), 10 panicles were harvested at maturity from five randomly chosen plants in each of the plot. the number of filled, unfilled and total grain was also counted to compute fertile spikelet percentage panicle-1 as kumar (2016). fertile spikelet panicle-1(%) = ��.�� ������ ������ �� ��� ������� ����� ��.�� ������ �� ��� ������� 100 yield determination to determine the yield per plot, the 3 m2 area (from the middle portion of each plot) was separately harvested and bundled, properly tagged, and then brought to the threshing floor for recording grain and straw yield. threshing was done using pedal thresher. both grain and straw were sun-dried immediately after harvesting. the harvested grain was cleaned and sun-dried to a moisture content of 14% (measured by grain moisture meter). finally, grain and straw yields per plot were determined and converted to ton per hectare (t ha-1). then biological yield was calculated following the formula (youshida, 1981): biological yield (t ha-1) or total dry weight (t ha-1) = grain yield (t ha-1) + straw yield (t ha-1) the harvest index was determined according to gardner et al. (1985) and the formula was, harvest index (%) = ����� ����� ���������� ����� 100 grain quality parameters assessment milling recovery: a hundred gram sample of dried (14% moisture) paddy grain samples i. e. rough rice were dehulled to produce brown rice in a satake laboratory sheller. the brown rice was milled in mcgill mill number 2 (adair, 1952). the total milled rice was calculated with the following formula (khushet al., 1979). total milled rice (%) = ������ �� ������ ���� ������ �� ����� ���� �� ����� ������ 100 head rice recovery: the broken grains were separated from the whole grains by using a grain grader and the rice kernel length greater or equal to three quarters was also considered as whole kernel.the percentage of the head rice recovery was calculated using the following equation: head rice recovery = ������ �� ���� ���� ������ �� ����� ������ 100 grain classification: ten de-husked entire brown rice grains were measured using digital slide calipers and based on the l/b ratio, size and shape were classified according to table 1 and table 2. table 1. classification of grain size scale size category length (mm) 1 very long more than 7.50 3 long 6.61 to 7.50 5 medium or intermediate 5.51 to 6.60 102 paul et al. 7 short less than 5.50 or 5.50 source. cruz and khush (2000) and irri standards table2. classification of grain shape scale shape l/b ratio (mm) 1 slender over 3.0 5 medium 2.1 to 3.0 9 bold 2.0 or less than 2.0 source. cruz and khush (2000) and irri standards kernel length after cooking: kernel length after cooking (klac) was measured according to bhonsle and krishnan (2010). rice samples were cooked in a water bath for 20 min, followed by ten selected (intact at both ends) cooked rice placing on blotting paper. finally, the length of the kernels was measured using graph paper for computing the klac. aroma content: the aroma content of all rice germplasm was evaluated according to irri (1971). one gram of freshly harvested milled rice was mixed with 20 ml of distilled water and placed into a centrifuge tube (50 ml round bottom). the tubes were then covered with aluminum foil. the samples were placed in a boiling water bath for 10 minutes. the cooked samples were allowed to cool and the presence of aroma was smelled by a panel of experts to score as strongly aromatic, moderately aromatic, slightly aromatic and non-aromatic. a strongly scented genotype (kalizira) was used as a check for comparison. statistical analysis: all the data were analyzed using the r program for statistical analysis. the means were separated using the least significant difference (lsd) test at the 0.05 level. results and discussion this investigation successfully evaluated the growth, yield contributing characters, yield and physicochemical quality of different native aromatic aman (growing season july to december) rice genotypes. morphological characteristics plant height: plant height is an important morphological parameter as this positively correlated to lodging (navadiet al., 2006). additionally, lodging disturbs the ripening process, decreases crop yield, and causes poor grain quality (kono, 1995). the plant height at harvest for all genotypes ranged from 219.08 cm to 107.09 cm and the genotypes differed significantly (table 3). this result was supported by hossain et al.(2008) stated that the popular aromatic rice cultivars in bangladesh were local with long-statured in nature and very much prone to lodging. sau adl11 produced the shortest plant (107.09 cm) which was statistically similar to sau adl4 (111.68 cm), sau adl5 (111.89 cm) and did not lodge during the maturity stage. the highest plant height was obtained from sau adl10 (219.08 cm) where kataribhog the popular aromatic rice cultivar provided the third highest plant height (167.17 cm) which was statistically similar with sau adl2 (159.57 cm), sau adl3 (173.26 cm) and these long-statured plant demonstrated lodging. this result indicated that the lodging of rice plants is highly associated with plant stature and short-statured genotypes could be useful for the lodging resistant genotypes. previously okuno et al. (2014) also recorded that the short height rice genotypes are resistant to lodging. total tiller numbers hill-1: tillering is a vital determinant of panicle production as well as yield in rice (miller et al., 1991). the current study found that the total tillers hill-1 at the harvesting stage varied among the evaluated genotypes. the highest total tiller numbers hill-1at harvest was observed in the local aromatic rice genotype sau adl10 (18.75) followed by sau adl5 (15.58).the total tiller numbers hill-1 of sau adl1, sau adl3, sau adl4, sau adl6, sau adl8, sau adl11 and screening of advanced aromatic rice lines using 101 kataribhog were statistically similar with sau adl5. the minimum tiller numbers hill-1 (6.58) was obtained from sau adl12 (table 3). table 3. morphological characters such as plant height and total number of tillers hill-1 at harvest, and days to maturity of evaluated rice genotypes genotypes plant height (cm) total tillers hill-1 (no.) maturity duration (days) sau adl1 124.16 e 15.36 b 134.67 c sau adl2 159.57 d 11.83 de 124.67 g sau adl3 173.26 c 14.50 bc 126.33 f sau adl4 111.68 fg 14.00 bcd 131.00 e sau adl5 111.89 fg 15.58 b 131.00 e sau adl6 166.14 cd 11.08 e 134.67 c sau adl7 119.56 ef 12.66 cde 135.67 b sau adl8 119.73 ef 13.17 bcdee 135.67 b sau adl9 194.72 b 11.83 de 133.33 d sau adl10 219.08 a 18.75 a 134.33 c sau adl11 107.09 g 13.33 bcde 136.00 b sau adl12 202.25 b 6.58 f 138.67 a kataribhog 167.17 cd 15.00 bc 135.67 b lsd(0.05) 8.74 2.65 0.78 cv (%) 3.41 11.76 0.35 the means with the same letter in a column show an insignificant difference at the 5% level maturity duration:sau adl12 recorded the maximum days (138.67 days) for maturity, whereas the minimum days (124.67 days) was recorded in sau adl2. local check kataribhog recorded 135.67 days for maturity where short statured genotypes sau adl4, sau adl5 and sau adl11 recorded 131.00, 131.00, 136.00 days, respectively. the variations in tillering and days to maturity might be the varietal variation. previously several authors (hossain et al., 1991 and jisan et al., 2014) also identified the difference in the genetic makeup as the reason for these variations during evaluation of different lines. yield and yield contributing parameters panicle length and fertile spikelets panicle-1 (%): maximum panicle length (32.63 cm) was recorded in genotype sau adl10 followed by sau adl9 (30.75 cm) which was statistically similar to sau adl3 (30.67), sau ad6 (29.62) (table 4). a minimum panicle length of 26.33 cm was recorded in sau ad7 which was statistically similar to sau ad1, sau ad2, sau ad4, sau ad11 and kataribhog (table 4). the highest fertile spikelets panicle-1 (%) was found in sau adl2 (91.57%) followed by kataribhog (83.15 %). the lowest fertile spikelets panicle-1 (%) was recorded from sau adl7 (27.44 %). short statured genotypes sau adl4, sau adl5 and sau adl11 had 52.02 %, 64.50% and 69.52 % fertile spikelets panicle-1, respectively (table 4). effective tillers hill-1: the number of panicles or effective tillers hill-1 is the most important component of rice yield (shahidullahet al., 2009). the maximum effective tillers hill-1 (16.75) was recorded from the genotype sau adl10 (table 4).kataribhog also produced second highest tillers m2, which was statistically similar to sau adl3, sau adl7, sau adl11, and sau adl5 (table 4). 102 paul et al. on the other hand, the least effective tillers hill-1were recorded in sau adl12 (5.33) which was statistically similar to sau adl6 (7.67). this result was similar to hossain et al. (2005) who found variation among the evaluated native aromatic rice cultivars in case of fertile tillers hill-1 which ranged from 8.6 to 11.4. thousand-grain weight: thousand-grain weight is an important yield-determining component, which is also a genetic character least influenced by the environment (ashraf et al., 1999). yoshida (1981) reported that under most conditions, 1000 grains of field crop is a very stable character. the highest thousand grain weight (31.97 g) was obtained from the genotype sau adl4 (31.97 g) which was statistically similar to sau adl1 (31.03g) and sau adl9 (31.03 g). on the other hand, the lowest thousand grain weight (15.03 g) was obtained from kataribhog. moreover the thousand grain weight of sau adl11 was 21.88 g which was statistically similar with sau adl7 (table 4). the main cause of the highest and lowest 1000-grain weight could be the long-slender grain size and short-medium grain size of genotypes respectively. the previous study found that grain size determines grain weight and affects grain quality (jiang et al., 2015). grain yield and harvest index (hi): grain yield and harvest index differed significantly among the local aman rice germplasms (table 4). the highest grain yield (4.79 tha-1) was obtained from sau adl5 which was statistically similar to sau adl2 (4.55 tha-1), sau adl3 (4.47 tha-1) and sau adl9 (4.48 tha-1). the lowest grain yield (2.59 t ha-1) was recorded from sau adl7 which was statistically similar to sau adl6 (2.86 tha-1), sau adl12 (2.81 tha-1), kataribhog (2.71tha-1). however, hossain et al. (2005) observed 3.3 t ha-1 yield in kataribhog and hoque et al. (2013) found 2.63 t ha-1 yield in kataribhog.the reasons behind this yield could be the result of number of effective tillers hill-1, fertile spikelets panicle-1 (%) and 1000-grain weight (g). this result was also in agreement with hassan et al. (2003) who stated that grain yield is a function of the interplay of various yield components such as the number of productive tillers, fertility percentage panicle-1 and 1000-grain weight. table 4. yield and yield contributing characters of evaluated rice genotypes after harvest genotypes panicle length (cm) fertilespikelets panicle-1 (%) effective tillers hill-1 (no.) 1000-grain weight (g) grain yield (tha-1) harvest index (%) sau adl1 26.79f 43.34 g 12.69 bc 31.03 ab 3.50 cde 37.75 b sau adl2 26.95ef 91.57a 10.50 de 29.96 bc 4.55 ab 43.50 a sau adl3 30.67bc 50.95fg 13.92cbc 26.02 f 4.47 ab 20.40 de sau adl4 27.33ef 52.02 f 12.58 bc 31.97 a 3.46 cde 37.17 b sau adl5 28.27de 64.50cd 14.34 b 29.25 cd 4.79 a 34.69 b sau adl6 29.62 bcd 54.14ef 8.42 f 28.97 cd 2.86 ef 20.09 de sau adl7 26.33 f 27.44h 10.67 de 22.34 g 2.59 f 19.18 de sau adl8 29.33cd 61.43de 9.17 ef 28.10 de 3.10 def 36.88 b sau adl9 30.75b 72.15c 9.92 ef 31.03 ab 4.48 ab 33.57 b sau adl10 32.63a 68.75cd 17.08 a 27.22 ef 3.92 bc 16.84 e sau adl11 26.39f 69.52c 12.08 cd 21.88 g 3.84 bcd 35.34 b sau adl12 29.59bcd 54.76ef 5.33 g 27.83 de 2.81ef 23.18 cd kataribhog 27.47ef 83.150b 13.00 bc 15.17 h 2.71ef 27.75 c lsd(0.05) 1.37 8.02 1.88 1.68 0.81 5.05 cv (%) 2.84 7.8 9.7 3.68 13.20 10.07 the means with the same letter in a column show an insignificant difference at the 5% level screening of advanced aromatic rice lines using 101 according to youshida (1981), the harvest index of traditional tall varieties is about 30% and for improved short varieties it is 50% and the identified reason is that dry mater partitioning to economic part is higher in short-statured varieties than the traditional one. the highest harvest index was found from the genotype sau dl2 (43.50%). the lowest harvest index (16.84%) was found from sau adl10 which was statistically similar to sau adl6, sau dl7, and sau adl3. harvest index of local cultivar kataribhog was 27.75 %, where hi of short-statured genotypes sau adl4, sau adl5 and sau adl11 was 37.63%, 35.57%, and 35.34% respectively. physico-chemical parameters physical properties include kernel size, shape, milling recovery, degree of milling and grain appearance (cruz and khush, 2000) and physico-chemical properties include cooking and eating quality like kernel length after cooking, aroma (rebeiraet al., 2014). milling recovery (mr) (%) and head rice recovery (hrr) (%): milling yield is an important physical property of rice especially for market value (rosniyana et al., 2006). a variety should possess a high turn-out of whole-grain (head) rice and total milled rice (webb, 1985). this criterion is important because it expresses the actual yield of a consumable product. the typical range of milling recovery was from 68 to 72 percent (hardke and siebenmorgen, 2012). the highest mr (75.92%) (figure 1a) and hrr (68.64%) (figure 1b) were recorded in kataribhog. both mr (74.41%) and hrr (65.71%) of sau adl11 were statistically similar to kataribhog. the lowest mr (48.82%) and hrr (35.51%) were recorded from sau adl7. short-statured genotypes sau adl4 and sau adl5 had 69.19% and 70.36% milling recovery, respectively. besides short stature genotypes sau adl4 and sau adl5 showed 58.94% and 58.41% of hrr, respectively. the mr% of rest genotypes lays 65.24% to 74.41%. ahmed et al. (2016) also assessed agro-morphological, physico-chemical and molecular characters of rice germplasm in bangladesh and found 65.3% to 69.9% milling rate. this study was also similar to hossain et al.(2008) who evaluated several local aromatic rice genotypes and reported 67.3% and 67.8% hrr in kataribhog (philippine) and kataribhog (deshi), respectively. the reason for this variation could be the result of different grain size and shape, moreover its a varietals characteristic (ferdouset al., 2004). 0 20 40 60 80 100 sau adl1 sau adl2 sau adl3 sau adl4 sau adl5 sau adl6 sau adl7 sau adl8 sau adl9 sau adl10 sau adl11 sau adl12 kataribhog m ill in g re co ve ry (% ) genotypes a 102 paul et al. fig. 1. milling recovery (%) and head rice recovery (%) of evaluated local aman rice genotypes. a) millingrecovery (%)of evaluated local aman rice genotypes. b) head rice recovery (%) of evaluated local amanrice genotypes. vertical bars mention the lsd(0.05) values. kernel length (mm) and breath (mm):grain size and shape are the first criteria of rice quality that breeders consider in developing new varieties for release for commercial production (adair et al., 1966). aromatic variety with kernel length 6.0 mm and above is considered a widely acceptable size (kaul, 1970). the highest kernel length (7.31mm) was obtained from sau adl1 followed by sau adl9 (7.22 mm) (table 5). meanwhile, the highest kernel breadth (2.62 mm) was obtained from sau adl2. the lowest kernel length (4.87 mm) and breadth (1.8 mm) was obtained from kataribhog. kernel length of short statured genotypes sau adl4, sau adl5, and sau adl11 was 7.01mm, 6.78mm, and 6.57mm respectively. in this investigation, the kernel length of all evaluated local germplasm was more than 6 mm and considered to be premium quality. however, kataribhog does not meet the acceptable range. islam et al. (2016) also reported medium bold scented grain in kataribhog and that was similar to the study. kernel size and shape:furthermore, the l/b ratio formulates the grain shape and the length and breadth ratio of all studied genotypes was also between the acceptable ranges 2.5 mm to 3mm (kaul, 1970). kernel length and breadth ratio of all the genotypes ranged from 3.77 mm to 2.37 mm (table 5). the highest ratio (3.77) was obtained from sau adl8 followed by sau adl7, sau adl3, sau adl10 and sau adl1. however, the lowest ratio (2.37) was obtained from sau adl2. the kernel size of sau adl1, sau adl3, sau adl4, sau adl7, sau adl8 and sau adl10 were long and slender; sau adl5 was long medium; sau adl6, sau adl9 and sau adl11 were medium slender and sau adl2 and sau adl12 were of medium type. on the other hand the kernel size of the check variety (kataribhog) was of short medium type. the result was similar to hossain et al. (2008) who reported 5.2 mm kernel length and 2.3 length-breadth ratios in kataribhog (philippines) and also 4.90 mm grain length and 2.5 length-breadth ratios in kataribhog (deshi). however, the result was not supported by dutta et al. (1998) who analyzed seven aromatic rice and reported 5.97mm kernel length and 3.09 length-breadth ratio in kataribhog. table 5. physico-chemical characteristics and aroma content of evaluated genotypes 0 20 40 60 80 100 sau adl1 sau adl2 sau adl3 sau adl4 sau adl5 sau adl6 sau adl7 sau adl8 sau adl9 sau adl10 sau adl11 sau adl12 kataribhog h ea d ric e re co ve ry (% ) genotypes b screening of advanced aromatic rice lines using 101 treatments kernel length (mm) kernel size kernel breadth (mm) l/b ratio kernel shape kernel length after cooking (mm) aroma content sau adl1 7.31 a long 2.23 de 3.28 bcd slender 9.34 b non-aromatic sau adl2 6.27 h medium 2.62 a 2.37 h medium 8.11 f non-aromatic sau adl3 7.13 abcd long 2.10 f 3.40 b slender 9.20 bc moderately aromatic sau adl4 7.01 bcde long 2.25 de 3.13 cd slender 8.91 cd non-aromatic sau adl5 6.78 efg long 2.33 cd 2.92 ef medium 9.99 a moderately aromatic sau adl6 6.93 cde long 2.43 bc 2.86 fg medium 9.13 bcd non-aromatic sau adl7 6.62 fg long 1.93 g 3.43 b slender 8.00 f moderately aromatic sau adl8 7.19 abc long 1.93 g 3.77 a slender 8.99 bcd non-aromatic sau adl9 7.22 ab long 2.52 ab 2.88 fg medium 9.19 bc moderately aromatic sau adl10 6.89 def long 2.09 f 3.30 bc slender 9.03 bcd moderately aromatic sau adl11 6.57 g medium 2.13 ef 3.08 de slender 8.53 e moderately aromatic sau adl12 6.60 g medium 2.33 cd 2.87 fg medium 8.78 de slightly aromatic kataribhog 4.87 i short 1.80 h 2.70 g medium 6.77 g strongly aromatic acceptable range >6 mm >3 lsd(0.05) 0.29 0.13 0.20 0.38 cv (%) 2.53 3.39 3.82 2.54 the means with the same letter in a column show an insignificant difference at the 5% level kernel length after cooking (klac): results revealed that klac of screened rice ranged from 8 mm to 9.99 mm (table 5). the highest klac (9.99mm) was found in sau adl5 and the lowest klac (6.77mm) was found in kataribhog. aroma: aroma varied among the varieties (table 5). among the genotypes sau adl3, sau adl5, sau adl7, sau adl9, sau adl10, sau adl11 were moderately aromatic. sau adl12 was slightly aromatic. sau adl1, sau adl2, sau adl4, sau adl8 were non-aromatic. the check kataribhog was strongly aromatic.islam et al.(2018) also found variability among 113 aromatic rice germplasms of bangladesh and reported that more than 58% of the germplasm were well scented, 31% germplasm were moderately scented, and 11% germplasm were non-scented. moreover, several authors (hossain et al., 2008 and islam et al., 2016) evaluated local cultivars and reported moderate to the strong aroma in the evaluated aromatic rice cultivars. conclusion the short-statured lodging resistant aromatic rice genotypes sau adl5 and sau adl11 along with the quality grain and higher yield can be evaluated at different agro-ecological zone of bangladesh to promote as improved genotypes for cultivation. other genotypes could be preserved as improved breeding materials. references 102 paul et al. adair, c.r, h.m. beachell, n.e. jodon, t.h. johnston, j.r. thysell, v.e. jr. green, b.d. webb and j.g. atkins.1966. rice breeding and testing methods in the us. in: us dept. of agric. rice in the us: varieties and production. usda agr. res. sew. handbook.289: 19-64. adair, c.r. 1952. the mcgill miller method for determining the milling quality of small samples of rice.rice j.55(2): 21-23. ahmed, m.s.u., m. khalequzzaman, m.k. bashar anda.k.m. shamsuddin. 2016. agro-morphological, physico-chemical and molecular characterization of rice germplasmwith similar names of bangladesh. rice sci. 23(4):211–218. ahmed, m.s., k. akter, m. khalequzzaman, e.s.m.h. rashid and m.k.bashar.2010. diversity analysis in boro rice (oryza sativa l.) accessions.bangladesh j. agric. res. 35(1): 29-36. aljumaili, s.j., m.y. rafii, m.a. latif, s.z.sakimin, i.w.aroluand g. miah. 2018.genetic diversity of aromatic rice germplasmrevealed by ssr markers. bio. med.res.intl.2018:1-11. ashraf, a, a. khalid and k. ali. 1999.effect of seedling age and density on growth and yield of rice in saline soil.pak. j. biol. sci.30(2): 860–862. ashrafuzzaman, m., m.r. islam, m.r. ismail, s.m. shahidullah and m.m. hanafi. 2009.evaluation of six aromatic rice varieties for yield and yield contributing characters.intl. j. agric. biol.11(5): 616– 620. bhonsle, s.j. and s. krishnan. 2010. grain quality evaluation and organoleptic analysis of aromatic rice varieties of goa. india j. agric. sci. 2(3):99-107. cruz, n.d. and g.s. khush. 2000.rice grain quality evaluation procedures. in:r.k. singh, u.s. singh and g.s. khush, eds., aromatic rice. oxford and ibh publishing co. pvt. ltd., new delhi, calcutta, pp.15-28. dutta, r.k., b.p. lahiriandm and a.b. mia. 1998. characterization of some aromatic and fine rice cultivars in relation to their physico-chemical quality of grains.indian j. plant physiol. 3(1): 61-64. ferdous, n., s.k. biswas and k.a. kabir. 2004.effect of milling on physiological properties of rice. in: proc. seminar. bangladsh rice. res. inst.gazipur. pp.1-5. gardner, f.p., r.b. pearce and r.l. mistechell. 1985.physiology of crop plants.iowa state univ. press, powa.p.66. giraud, g. 2013. the world market of fragrant rice, main issues and perspectives. int. food agribusi.mng. 16(2):20. hardke, j.t. and t. siebenmorgen. 2012.http://www.deltafarmpress.com/rice/production-factors-affectingrice-milling-quality. hassan, g., n.u. khan and q.n. khan. 2003.effect of transplanting date on the yield and yield samples of rice.rice j.55(2): 21-23. hoque, m., f. yeasmin and m.m. haque. 2013.screening suitable aromatic rice variety for sylhetregion of bangladesh.bjpst.11(1): 041-044. hossain, m.b., m.o. islam and m. hasanuzzaman. 2008. influence of different nitrogen levels on the performance of four aromatic rice varieties.int. j. agri. biol.10: 693–696. hossain, m.f., m.s.u. bhuiya and m. ahaed. 2005. morphological and agronomic attributes of some local and modern aromatic rice varieties of bangladesh. asian j. plant sci.4: 664–666. hossain, s.m.a., a.b.m.m. alam and m.a. kashem. 1991.states of crop production technology. in: fact searching and intervention in two fsrdp sites activities 1990-1991. farming system research and development programme, bangladesh agricultural university, mymensingh, pp.150-154. international rice research institute. 1971. annual report for 1970. los baños, laguna, philippines.p.265. islam, m.z., m. khalequzzaman, m.k. bashar, n.a. ivy, m.m.haque, and m.a. mian. 2016.variability assessment of aromatic and fine rice germplasm in bangladesh based on quantitative traits. thescientificworldj. 2796720. doi:10.1155/2016/2796720. screening of advanced aromatic rice lines using 101 islam, m.z., m. khalequzzaman, m.k. bashar, n.a. ivy, m. mian, b.r. pittendrigh, m.m. haque andm.p. ali. 2018. variability assessment of aromatic rice germplasm by pheno-genomic traits and population structure analysis. sci.reports, 8(1): 9911. doi:10.1038/s41598-018-28001-z. islam, n., m.y. kabir, s.k.adhikary andm.s. jahan. 2013. yield performance of six local aromatic rice cultivars. iosr j. agric. veter. sci. (iosr-javs). 6(3): 58-62. jiang. h., w. yuexing, f. yunxia, z. longjun, x. jie, y. haiping, s. zhenyuan, p.jiangjie, z. dong, k. shujing, z. li, d. guojun, g. longbiao, z. dali, z. guangheng, x. lihong, x. guosheng, l. jiayang and q. qian. 2015.a rare allele of gs2 enhances grain size and grain yield in rice. molecular plant.8(10): 1455-1465. jisan, m.t., s.k. paul and m. salim. 2014. yield performance of some transplant aman rice varieties as influenced by different level of nitrogen. j. bangladesh agril. univ.12: 321-24. juliano, b.o. and d.b. bechtel. 1985.the grain and its gross composition. in: rice chemistry and technology. los banos, laguna: irri. pp.17–57. kaul, a.k. 1970. 'early generation testing for quality characteristics'. ii. rice indian j. genet. plant breed.30: 237-243. khalequzzaman, m., m.a. siddique and m.k. bashar. 2012. rice genetic resources conservation and utilization in bangladesh: in proceedings of the national workshop on plant genetic resources for nutritional food security. pp.50–60. khalid, m., k.n.u. farahatullah,a. din andm.y. khan. 2010. linkage of morphological markers in brassica. pakistan j. bot. 42(5):2995–3000. khush, g.s., m. paule and n.m. delacruz. 1979.grain quality evaluation and improvement at irri. in: proceeding of workshop on chemical aspect of rice grain quality. international rice research institute, philippines, pp.21-31. kono, m. 1995. physiological aspects of lodging. in: matsuo, t., k.kumazawa, r. ishii, k. ishihara, h. hirata eds. science of the rice plant, volume 2, physiology. tokyo: food and agriculture policy research center.pp.971–982. krishna, l., s.c. raju, s.s. kumar, j. bhadru and y.c. mohan. 2018. genetics of quality and yield traits using aromatic and non-aromatic genotypes through generation mean analysis in rice (oryza sativa l.).int.j.curr.microbiol.app.sci.7(1): 2907-2914. kumar, v. 2016. characterization, inheritance and allelic relationship study of gene(s) governing aroma and quality traits in rice (oryza sativa l.).ph.d. thesis, indira gandhi krishivishwavidyalaya, raipur (chhattisgarh), india, p.52. louis, m.t.b, j.h. robert, j. qingsheng, f.r. russell and l.e.w. daniel. 2005.a perfect marker for fragrance genotyping in rice.molecular breed.16:279-283. miller, b.c., j.e. hill and s.r. roberts. 1991. plant population effects on growth and tied in water-seeded rice. agron. j.83: 291–297. mia, m.a.b., m.r. das, m. kamruzzaman andn.m. talukder. 2012.biochemical traits and physicochemical attributes of aromatic-fine rice in relation to yield potential.am. j. plant sci. 3: 17881795. navadi, a., m. iqbal, k. stranzke andd. spaner. 2006. the relationship between lodging and plant height in a diverse wheat population. can. j. plantsci. 86(3):723-726. okuno, a., k. hirano, k. asano, w. takase, r. masuda, y. morinaka, m. ueguchi-tanaka, h. kitano andm. matsuoka. 2014. new approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties. plos one. 9:1–12. rebeira, s.p., h.a.m. wickramasinghe, w.l.g. samarasinghe and b.d.r. prashantha. 2014. diversity of grain quality characteristics of traditional rice (oryza sativa l.)varieties in sri lanka.trop. agric. res.25(4): 570 – 578. rosniyana, a., m.a. hashifah and s.a. shariffahnorin. 2006. quality evaluation of retailed packed malaysian milled rice sold in the market. j. trop. agric. food sc. 34(1): 45 – 55. 102 paul et al. roy, p.s., r. samal, g.j.n.d. rao, s.s.c. patnaik, n.n. jambhulkar, a. patnaik and t. mohapatra. 2016. differentiation and description of aromatic short grain rice landraces of eastern indian state of odisha based on qualitative phenotypic descriptors. bmc ecol. 16: 36. sakthivel, k., r.m. sundaram, s.n. rani, s.m. balachandran and c.n. neeraja. 2009. genetic and molecular basis of fragrance in rice.biotechnol. adv.27:468-473. shahidullah, s.m., m.m. hanafi, m. ashrafuzzaman, m.r. ismail and m.a. salam. 2009.tillering dynamics in aromatic rice genotypes.int. j. agric. biol.11: 509–514. webb, b.d. 1985. criteria of rice quality in united states. in: rice chemistry and technology, los banos, laguna: irri. pp.403–442. yoshida, s. 1981. yield and yield components. in: fundamentals of rice crop science. irri, manila, philippines. pp.60-63. screening of advanced aromatic rice lines using morphological and physico-chemical characteristics keywords: aromatic rice, morphological, physic-chemical characteristics, yield abstract introduction materials and methods results and discussion the short-statured lodging resistant aromatic rice genotypes sau adl5 and sau adl11 along with the quality grain and higher yield can be evaluated at different agro-ecological zone of bangladesh to promote as improved genotypes for cultivation. other genotypes could be preserved as improved breeding materials. roy, p.s., r. samal, g.j.n.d. rao, s.s.c. patnaik, n.n. jambhulkar, a. patnaik and t. mohapatra. 2016. differentiation and description of aromatic short grain rice landraces of eastern indian state of odisha based on qualitative phenotypic descriptors. bmc ecol. 16: 36. bangladesh agron. j. 2015, 18(1): 49-52 intercropping maize with different vegetables m. r. ali1, m. s. rahman2, m. asaduzzaman1, m. m. hossain1 and m. a. mannan3 1senior scientific officer, regional agricultural research station, bari, jamalpur, 2upazila agriculture officer, dae, gopalpur, tangail, 3principal scientific officer, regional agricultural research station, bari, jamalpur key words: intercropping, maize, vegetable, equivalent yield, economics abstract an intercropping experiment was conducted in the farmer’s field at farming systems research and development (fsrd) site, kushumhati, sherpur in sandy loam soil of medium high land during rabi season 2011-12 to observe the productivity and economic feasibility of intercropping systems as compare3d to sole crop (viz. maize + potato, maize + radish, maize-+-coriander, maize + bushbean, maize + spinach, maize + lalshak and maize sole). the result indicated that grain yield of maize was reduced due to intercropping systems but this reduction was compensated by intercropped. the highest grain yield of maize was found from sole maize (10.90 t ha-1) and lowest (9.32 t ha-1) from intercropped with potato. the maximum maize equivalent yield (14.04 t ha-1), gross return (tk.10,5300/ha),gross margin (tk. 75,527/ ha),, and benefit cost ratio (bcr) (3.54) was obtained from maize + bushbean intercropping systems which was adventitious over sole maize cropping. introduction maize is one of the most important cereal crops in the world both as food for human and feed for animals. it is the most efficient crop which can give high biological yield as well as grain yield relatively in a shorter period of time due to its unique photosynthetic mechanism as c4 plant (hatch and slack, 1996). in bangladesh, the cultivable land is declining day by day. so, the production of food grain could be increased by adopting intercropping system. intercropping is the practice of growing two or more crop together in the same piece of land in stipulated time, particularly in the tropics. the vegetable production could be increased through intercropping practices as the horizontal expansion of area is limited. maize as wider spaced plant offers some component crops to grow together without economic loss sacrificing small maize yield with greater total production in respect of land and time. this practice offered considerable yield advantages and higher economic return over sole intercropping because of its efficient utilization of growth resources (faruque et al., 1996). the results of intercropping maize with legumes and vegetables is a profitable system as reported by uddin and satter (1993). moreover, little information is available for suitable intercrop combination of vegetables with maize. considering the above facts, the experiment was undertaken to find out the suitable intercropping system of vegetables with maize for increasing total productivity, return and maximize land utilization. materials and methods the experiment was conducted at the farming system research and development (fsrd) site, kushumhati, sherpur during the rabi season 2011-12. the soil was sandy loam of old brahmaputra floodplain under aez 9. the experiment consisted of seven treatmernts, viz. i) 50 ali et al. maize + potato ii) maize + radish iii) maize + coriander iv) maize + bushbean v) maize + spinach vi) maize + lalshak and vii) maize sole. the treatments were tested in randomized complete block design with 3 replications. the unit plot size was 4.5 m x 5 m. the variety pacific 11, dhira, druti, local, bari jharsheem 1, local and bari lalsak 1 were used for maize, potato, radish, coriander, bushbean, spinach and lalsak, respectively. all vegetables were sown in lines in between the maize rows maintaining the standard spacing of the respective vegetables. maize seeds were sown in a planting configuration of 75 cm x 25cm spacing and fertilized at the rate of 256-55-138-3-1 kg ha-1 of npksb and cow dung at the rate of 5 t ha-1. full amount of pksb, 2/3rd of n and 12 kg ha-1 (furadan) along with full amount of cow dung were applied at the time of final and preparation. the rest n was applied into two equal splits at 8-10 leaves stage and at tasselling stage. seeds of maize and all other vegetables were sown on november 28, 2011. intercropped vegetables were harvested depending on the maturity of the individual crops ranging from december 28, 2011 to february 6, 2012 and maize was harvested on april 19, 2012. intercultural operation was done as and when necessary. grain yield of maize was determined at 14% moisture content. equivalent yield of component crops were determined following the method of anjaneyulu et al. (1982). maize equivalent yield (mey) = ym+ pm piyi where, ym = yield of maize (t ha-1) yi = yield of intercrop vegetable (t ha-1) pi = price of intercrop vegetables (tk ha-1) pm = price of maize (tk ha-1) data recorded on the different parameters were analysed and means were separated following dmrt test at 5% level of significance. results and discussion the result indicated that most of the yield attributes were significantly influenced due to maize vegetable intercropping but cobs/plant and 1000-grain weight was found insignificant (table 1). the highest grains/cob (458.6) was achieved from sole maize and it was statistically similar to other treatments except maize + potato and maize + radish treatments which produced the lowest grains/cob (415.3) the maximum grain yield (10.90 t ha-1) was recorded from sole maize and it was statistically identical to all other treatments except maize + potato (9.70 t ha-1) and maize + radish (9.92 t ha-1). ofrd (2006) and bhuiyan et al., 1999 also reported that sole maize gave the highest yield among the treatments. all the treatments showed similar straw yield except maize + radish which gave the lowest yield (4.87 t ha-1). the highest maize equivalent yield (14.04 t ha-1) was produced by maize + bushbean treatment (table 3). the result confirms the findings of bhuiyan et al. (1999). other treatment showed lower maize equivalent yield of 11.32, 11.06, 10.81 and 10.66 t ha-1 from maize + spinach, maize + lalshak, maize + radish and maize + coriander, respectively. the lowest maize equivalent yield (10.16 t ha-1) was noticed from maize + potato treatment. the highest gross return was found from maize + bushbean intercropping (tk.1,05,300/ha while the lowest gross return (tk. 76,200 ha-1) was recorded from maize + potato combination. the total cost was found highest (tk. 42523 ha-1) in maize + potato treatment due to higher seed cost of potato (table 2). the lowest total cost was found from maize sole treatment. however, the highest benefit cost ratio was found in maize + bushbean intercropping system (3.54) and the lowest benefit cost ratio from maize + potato intercropping. santalla et al. (2001) was also found that greatest net 51 intercropping maize with different vegetables income from bushbean intercropped with sweet maize. all the intercropping system other than maize + bushbean failed to show higher benefit than sole maize. conclusion from the above result showed that maize intercropping with bushbean was found agronomically viable and economically profitable than sole crop of maize but other intercropping combinations failed to show higher benefit. table 1. yield attributes and grain yield of maize in different maize + vegetable intercropping systems intercropping system cobs/ plant (no.) grains/ cob (no.) 1000– grain weight (g) yield (t ha-1) stover yield (t ha-1) maize intercrop maize + potato maize + radish maize + coriander maize + bushbean maize + spinach maize + lalshak maize sole 1.10 1.06 1.06 1.06 1.11 1.30 1.08 415.3 b 427.9 b 451.4 a 453.3 a 450.7 a 447.2 a 458.3 a 320.33 320.00 320.33 320.67 320.00 320.33 330.00 9.70 b 9.92 b 10.54 a 10.57 a 10.50 a 10.49 a 10.90 a 10.08 8.12 0.64 6.27 5.08 3.31 5.50 ab 4.87 b 5.62 ab 5.73 ab 5.54 ab 6.03 a 6.37 a cv (%) 3.67 5.99 1.43 5.39 8.96 figure in the column having similar letter (s) do not differ significantly by dmrt test table 2. total cost involved in maize+vegetables intercropping systems intercropping system cost of fertilizer, irrigaion and labour (tk. ha-1) seed cost (tk. / ha) additional cost (tk. ha-1) total cost (tk. ha-1) maize + potato maize + radish maize + coriander maize + bushbean maize + spinach maize + lalshak sole maize 26557.00 26557.00 26557.00 26557.00 26557.00 26557.00 24632.00 13166.00 1766.00 2766.00 2166.00 3566.00 1366.00 1166.00 2800.00 1050.00 1750.00 1050.00 1050.00 1050.00 42,523.00 29,373.00 31,073.00 29,773.00 31,173.00 28,973.00 25,798.00 table 3. agronomic productivity and economics of maize-vegetables intercropping systems intercropping system maize equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio maize + potato maize + radish maize + coriander maize + bushbean maize + spinach maize + lalshak sole maize 10.16 10.81 10.66 14.04 11.32 11.06 10.90 76200 81075 79950 105300 84900 82950 81750 42523 29373 31073 29773 31173 28973 25,798 33677 51702 48877 75527 53727 53977 55952 1.79 2.76 2.57 3.54 2.72 2.86 3.17 seed price/kg: potato=tk.15.00, radish= tk.200.00, bushbean=tk.50.00, lalshak= tk.500.00, spinach= tk.30.00, coriander= tk. 40.00, maize= tk. 106.00.sell price/kg: potato=tk.4.00, radish= tk.1.00, bushbean=tk.7.00, lalshak= tk.3.00, spinach= tk.2.50, coriander= tk. 15.00, maize= tk. 7.50 52 ali et al. references anjaneyulu, v.r., s.p. singh and m. pal. 1982. effect of competition free period and technique and pattern of pearlmillet planting on growth and yield of mungbean and total productivity in solid pearlmillet/mungbean intercropping system. indian j. agron. 27: 219-226. bhuiyan, m. k. a., m. m. haque, q. a. khaliq, j. a. begum and a. h. m. r. mawlla. 1999. productivity and economics of grain legumes intercropped with maize. bangladesh agron. j. 9 (1&2): 35-42. faruque. a., a. hashem and a. jahan. 1996. productivity and profitability of potato intercropped with wheat. bangladesh j. bot. 25(1): 1-4. hatch, m.d. and c.r. slack. 1996. photosynthesis by sugarcane leaves. a new carboxylation reaction and pathway of sugar formation. biochem. j. 101(7): 103. on-farm research division (ofrd), bangladesh agricultural research institute, joydebpur, gazipur. 2006. intercropping maize with short duration vegetables crop. annual research report. pp 291-297. santalla, m., a. p. rodino, p. a. casquero and a. m. ron. 2001. interactions of bush bean with field and sweet maize. european j. agron. 15 (3): 185-196. uddin, m. s. and m. a. satter. 1993. prospects of intercropping maize with legumes and vegetables in hill tracts. bangladesh j. agril. res. 18(2): 227-230. microsoft word 10. baj-296_ revised bangladesh agron. j. 2018, 21(1): 89-94 development of fertilizer recommendation for blackgram in charland of pabna, bangladesh m. maniruzzaman1*, m. r. alam1, m.s. islam1, m.z. islam1, m.s.h. molla2 and m.a. islam3 1on-farm research division, bangladesh agricultural research institute, pabna 2on-farm research division, bangladesh agricultural research institute, rangpur 3on-farm research division, bangladesh agricultural research institute, shampur, rajshahi *corresponding author, e-mail: maniruzzaman.bari@yahoo.com (received: 21 december 2017, accepted: 23 march 2018) keywords: charland, aez, pulse, blackgram,yield, cost and return abstract the experiment was conducted at charland of charsadipur in pabna district under aez-11 during khrif season of 2014 and 2015 to determine appropriate fertilizer dose for enhancing yield of blackgram as well as to increase farmers’ income. the experiment was laid out in a randomized complete block design with four dispersed replications. eight fertilizer packages, viz.t1: n20p15k6s9zn2 kg ha-1(stb), t2: n25p15k6s9zn2kg ha-1, t3: n25p19k6s9zn2 kg ha-1, t4: n25p15k8s9zn2 kg ha-1, t5: n20p19k8s9zn2 kg ha-1, t6: n25p19k15s9zn2 kg ha-1, t7: n15p11k5s7zn1.5kg ha-1and t8: native nutrients (control) were tested on blackgram. fertilizer package of n25p19k15s9zn2 kg ha-1 (t6) enhanced crop growth and yield of blackgram in both the years. maximum seed yield of blackgram (1.43t ha-1 in 2014 and 0.97 t ha-1 in 2015) was obtained with n25p19k15s9zn2 kg ha-1 (t6), which was 80 and 147% more than the control in 2014 and 2015, respectively. the highest gross return (tk. 82815 ha-1 in 2014 and tk. 65200 ha-1 in 2015) and gross margin (tk. 51125 ha-1 in 2014 and tk. 32020 ha-1 in 2015) were also recorded from the same treatment in both the years. the results revealed that fertilizer package of n25p19k15s9zn2kg ha-1 might be recommended for getting higher seed yield of blackgram and economic return as well under charland condition of pabna district . introduction pulses are vital legume crops in bangladesh and used as food, feed and fodder. it is rich in protein. it also contains amino acid and lysine which are generally deficient in food grains (elias et al., 1986). pulses play an important role in sustaining soil health. they are generally grown without fertilizer since they can meet their nitrogen requirement by symbiotic fixation of atmospheric nitrogen in the soil (senanayake et al., 1987; zapata et al., 1987; fried and middleboe, 1977). the per capita consumption of pulse in bangladesh is only 12 g day-1, which is much lower than who recommendation of 45 g day-1 (afzal et al., 1999). blackgram (vigna mungo l.), one of the major pulse crop, stands fourth both in acreage and production in bangladesh. blackgram provides about 10.5% of the total pulse produced in bangladesh and its seed contains about 25% protein (bari, 1998). it is mainly grown for human consumption, though widely used as fodder for cattle and green manuring crop to improve soil fertility. in bangladesh the char lands of char area are not suitable for all types of crop. in pabna, there is a vast area of charland under aez-11. soil of charland is coarse textured having low water holding capacity, low nutrient and organic matter content. farmers of charland in pabna generally grow local variety of blackgram with no or limited fertilizers. for this reason, the 90 maniruzzaman et al. yield of blackgram in this region ismuch lower than that of potential yield. balanced fertilization can play a major role toenhance the present yield level. experimental evidences reveal that the crop is highly responsive to different fertilizers and its yieldcan be increased remarkably through judicious fertilization (bari, 1988; mohamed, 1984; roy and singh, 1986; kazi et al., 2002). fertilizer recommendation solely based on crop response data often fails to show economic viability. in this context, perrin et al. (1979) reported that response of yield should be supported by economic evaluation for judicious fertilizer recommendation. therefore, judicious application of fertilizer along with economic evaluation is important for blackgram. but very limited information is available in this regard in bangladesh context. hence, the present study was undertaken to determine the optimum fertilizerdose for getting higher economic benefit for blackgram in charland of pabna district. materials and method the experiment was conducted at charland of charsadipur in pabna district during the khrif-ii season of 2014 and 2015. soil series of the experimental site was gopalpur belonging to the high ganges river floodplain soils (aez-11). before sowing, initial soil samples (0-15 cm depth) were collected from the experimental plots and were analyzed. the analytical results indicated that soil was sandy loam with verylow organic matter content (0.78%) and slightly alkaline in nature. n content of soil was very low and p, s and zncontent were also low. k content of the soil was medium (table 1). the experiment was laid out in randomized complete block (rcb) design with three dispersed replications. the unit plot size was 5m x 4m. table 1. nutrient status of initial soil sample (0-15 cm depth) of experimental plots at charsadipur, pabna. soil properties values interpretation soil ph 8.1 slightly alkaline organic matter content (%) 0.78 very low total n (%) 0.05 very low available p (µgg-1 soil) 11.6 low available s (µgg-1 soil) 9.3 low available zn (µgg-1 soil) 0.56 low exchangeable k (meq%) 0.18 medium t1: n20p15k12s9zn2 kg ha-1 (stb), t2: n25p15k12s9zn2kg ha-1, t3: n25p19k12s9zn2kgha-1, t4: n25p15k15s9zn2kgha-1, t5: n20p19k15s9zn2kgha-1, t6: n25p19k15s9zn2kg ha-1, t7: n15p11k9s7zn1.5 kg ha-1 and t8: native nutrient (control). full amount of all fertilizers were applied as basal according to treatments. seeds of blackgram were broadcasted in each plot on 15-20 august maintaining the seed rate of 35 kg ha-1 in both the year . the variety used this trial was bari mash-3. two weedings were done at 25 and 40 days after sowing (das) for better growth of the crop. ripcord 50 ec was applied at 35 das to control leaf feeding insect. other intercultural operations were done when required. the above ground part of blackgram was harvested on 10-15 november in both the year. data on days to 50% flowering, days to 80% maturity were taken from all plots. plant height, pods plant1,seeds pod-1and 1000-seed weight were collected from randomly selected 10 plants at maturity stage from each plot. seed yield and stover yield were taken from whole plot. all collected data were analyzed statistically by using mstat package and the means were adjudged by lsd test at 5% level of significance. cost and return analysis of different treatments were also done . results and discussion development of fertilizer recommendation for blackgram 91 phenological characters phenological characters ofblackgram have been presented in table 2. significant variation in days to 50% flowering, days to 80% maturity and plant height were observed due to execution of different treatments. maximum days to 50% flowering (53 in 2014 and52 in 2015 ) and days to 80% maturity (74 in 2014and 83 in 2015) were recorded from n25p19k15s9zn2kg ha-1(t6) which was statistically different from all other fertilizer packages while minimum days to 50% flowering (46.67 in 2014 and 45.67 in 2015) and days to 80% maturity (70.67 in 2014 and 77.67 in 2015) were recorded from control plot (t8). the highest plant height (38.0 cm in 2014 and 50.3 cm in 2015) was measured from n25p19k15s9zn2kg ha-1 (t6) and the lowest plant height (33.43 cm in 2014 and 38.62cm in 2015) was recorded in control plot (t8). table 2. phenological parameters of blackgram as affected by different levels of nutrients during kharif season of 2014 and 2015 at charsadipur, pabna treatment days to 50% flowering (no.) days to 80% maturity (no.) plant height (cm) 2014 2015 2014 2015 2014 2015 t1: n20p15k12s9zn2 kg ha-1 (stb) 48.33 47.33 72.00 80.33 36.27 38.95 t2: n25p15k6s9zn2 kg ha-1 50.33 49.33 72.33 82.00 37.23 39.99 t3: n25p19k6s9zn2 kg ha-1 50.67 49.67 73.00 81.67 37.63 43.66 t4: n25p15k15s9zn2 kg ha-1 51.33 50.33 73.00 81.33 36.20 45.30 t5: n20p19k15s9zn2 kg ha-1 51.00 50.00 72.67 80.67 35.67 43.68 t6: n25p19k15s9zn2 kg ha-1 53.00 52.00 74.00 83.00 38.00 50.30 t7: n15p11k9s7zn1.5 kg ha-1 47.67 46.67 71.67 79.33 36.40 42.34 t8: control 46.67 45.67 70.67 77.67 33.43 38.62 lsd(0.05) 0.908 0.90 1.186 0.84 1.415 5.92 cv(%) 6.04 5.06 8.67 6.60 7.60 6.38 yield contributing characters yield contributing characters of blackgram are presented in table 3. significant variation in number of pods plant-1, number of seeds pod-1, and 1000 -seed weight were observed due to execution of different treatments. maximum number of pod plant-1 (24.47 in 2014 and 18.17 in 215) was found from n25p19k15s9zn2 kg ha-1 (t6) in both the year while minimumnumber of pods plant-1 (17.27 in 2014 and 14.23 in 2015) was recorded from control plot (t8). in case of number of seeds pod-1, no significant difference was found among the treatments except control. significantly higher 1000-seed weight was observed from in all the fertilizer packages over control in both the years and the lowest 1000 -seed weight (33.63 g in 2014 and 34.67g in 2015) from control plot (t8). table 3. yield contributing parameters of blackgram as affected by different levels of nutrients during kharifseason of 2014 and 2015 at charsadipur, pabna treatments pods plant-1 (no.) seeds pod-1 (no.) 1000-seed weight (g) 2014 2015 2014 2015 2014 2015 t1: n20p15k12s9zn2 kg ha-1 (stb) 19.44 16.73 6.850 6.32 34.77 34.90 t2: n25p15k6s9zn2 kg ha-1 20.04 16.97 6.900 6.37 34.80 34.93 92 maniruzzaman et al. t3: n25p19k6s9zn2 kg ha-1 21.07 18.07 7.010 6.53 34.90 34.97 t4: n25p15k15s9zn2 kg ha-1 19.30 17.63 7.060 6.50 35.27 35.13 t5: n20p19k15s9zn2 kg ha-1 20.81 17.83 6.830 6.77 35.17 35.47 t6: n25p19k15s9zn2 kg ha-1 24.47 18.17 6.767 6.83 35.40 35.90 t7: n15p11k9s7zn1.5 kg ha-1 18.04 15.67 6.50 6.00 34.73 35.00 t8: control 17.27 14.23 6.37 5.67 33.63 34.67 lsd (0.05) 3.24 2.125 0.65 0.53 0.896 1.088 cv (%) 9.25 5.17 5.49 2.45 1.47 1.77 yield and percent yield increase over control of blackgram have been presented in table 4.maximum stover yield of blackgram (1.77 t ha-1 in 2014 and 1.4 t ha-1 in 2015) was found from n25p19k15s9zn2kg ha-1 (t6) treatment and minimum stover yield (0.97 t ha-1 in 2014 and 1.0 t ha-1 in 2015) was found from control plot (t8). the highest seed yield (1.43 t ha-1 in 2014 and 0.97 t ha-1 in 2015) was obtained from n25p19k15s9zn2kg ha-1(t6) which was significantly higher than other treatments. on the contrary, control (t8) treatment provided the lowest seed yield (0.58 t ha-1in 2014 and 0.54 t ha-1 in 2015). the cumulative contribution of yield components might be the reason for higher seed yield in n25p19k15s9zn2kg ha-1(t6). in contrast, poor crop growth and lower yield components resulted the lowest seed yield in control treatment (t8). yield increase over control (147% in 2014 and 80% in 2015) was more in n25p19k15s9zn2kg ha-1 (t6). the overall results indicated that 100% soil test based fertilizer package plus 25% additional nutrients specially n, p and k that is fertilizer dose of n25p19k15s9zn2kg ha-1 (t6) enhance plant growth and produced higher yield in blackgram. this result is supported by the findings of kumar and singh (2009), mondal et al. (2010); bhuiyan et al. (2008) and singh et al. (2004) in case of lentil.they reported that balanced application of n, p, k, s, zn and b significantly increased yield of lentil over control. cost and return analysis cost and return analysis demonstrated that maximum gross return (tk. 94,650 ha-1 in 2014 and tk. 65,200 ha-1 in 2015) and gross margin (tk. 62,960 ha-1 in 2014 and tk. 32020 ha-1 in 2015) was obtained from n25p19k15s9zn2 kg ha-1(t6) followed by t4 and t5 fertilizer packages (table 5). higher production in this treatment resulted in higher economic return. total variable cost in different treatments varied mainly due to involvement of fertilizer cost. minimum gross margin (tk. 12,500 ha-1 in 2014 and tk. 8,650 in 2015 ha-1) was recorded in control plot (t8) might be due to lower yield. table 4. seed yield of blackgram as affected by different levels of nutrients during the kharifseason of 2014 and 2015 at charsadipur, pabna treatments stover yield (t ha-1) seed yield (t ha-1) seed yield increase over control (%) 2014 2015 2014 2015 2014 2015 t1: n20p15k12s9zn2 kg ha-1(stb) 1.22 1.23 0.80 0.68 38 26 t2: n25p15k6s9zn2 kg ha-1 1.33 1.29 0.86 0.77 48 43 t3: n25p19k6s9zn2 kg ha-1 1.37 1.25 0.96 0.67 67 24 t4: n25p15k15s9zn2 kg ha-1 1.37 1.30 1.10 0.83 90 54 t5: n20p19k15s9zn2 kg ha-1 1.40 1.24 1.27 0.69 119 28 t6: n25p19k15s9zn2 kg ha-1 1.77 1.40 1.43 0.97 147 80 t7: n15p11k9s7zn1.5 kg ha-1 1.20 1.08 0.74d 0.66 28 22 t8: control 0.97 1.00 0.58 0.54 lsd (0.05) 0.33 0.39 0.236 0.21 cv (%) 10.31 18.48 9.70 19.72 development of fertilizer recommendation for blackgram 93 table 5. cost and return analysis of blackgram influenced by fertilizer packages at charsadipur, pabna as affected by different levels of nutrients during kharif season of 2014 and 2015 treatments gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) 2014 2015 2014 2015 2014 2015 t1: n20p15k12s9zn2 kg ha-1 (stb) 54100 46950 30780 32294 23320 14656 t2: n25p15k6s9zn2 kg ha-1 58250 52650 30980 32470 27270 20180 t3: n25p19k6s9zn2 kg ha-1 64450 46450 31530 33020 32920 13430 t4: n25p15k15s9zn2 kg ha-1 72850 56300 31140 32630 41710 23670 t5: n20p19k15s9zn2 kg ha-1 83200 47600 31490 33004 51710 14596 t6: n25p19k15s9zn2 kg ha-1 94650 65200 31690 33180 62960 32020 t7: n15p11k9s7zn1.5 kg ha-1 49800 45000 29875 31400 19925 13600 t8: control 39650 37400 27150 28750 12500 8650 market price (tk. kg -1): blackgram: grain 60.00, straw 5.00 conclusion the results revealed that fertilizer packages exerted significant effect on growth and yield of blackgram. blackgram grown with n25p19k15s9zn2 kg ha-1 produced the highest yield and gave the maximum economic benefit at charland area of pabna district, bangladesh. references afzal, m. a., m. a. bakr and m. l. rahman. 1999. lentil cultivation in bangladesh. lentil, blackgram and mungbean development pilot project, pulses research station, bari, gazipur-1701. bari (bangladesh agricultural research institute). 1988. annual report 1988-89, pp. 136-142. bari, joydebpur, gazipur-1701, bangladesh. bhuiyan, m.a.h., d. khanam, n.e. ali, m.k. zaman and m.s. islam. 2008. response of lentil to bio fertilizer and chemical fertilizers in the farmers’ field. annual research report, 20072008, soil science division, bari, gazipur. elias. s.m., m.s. hossain, f.s. sikder, j. ahmed and m. r.karim. 1986. identification of constraints to pulse production with special reference to present farming systems. annual report of agricultural economic division, bari, joydebpur.p-1. fried, m. and v. middelboe. 1977. measurement of amount of nitrogen fixed by legume crop. plant and soil 47: 713-715. kazi, b. r., f. c.oad, and a. lakho. 2002.effect of irrigation frequencies on growth and yield of soybean. pakistan j. appl. sci. 2 (6): 661-662. kumar, s. and m. singh . 2009. 25 years of pulses research at iipr, 1984-2009. indian institute of pulses research, kanpur 208024, india. mohamed, s. a. 1984. effect of irrigation water and fertilization on yield and water use efficiency of corn plants in fayoum governorate. moshtohor, egypt annual agric. sci. 20(2): 221-235. mondal, r.h., b. anwar, m. rafiuddin and m.a. hossain. 2010. integrated nutrient management f or sustaining soil fertility and yield of lentil-mungbean-t.aman cropping pattern. annual research report, 2009-2010, pulses research centre, bari, gazipur. 94 maniruzzaman et al. perrin, r. k., d. l.winkelmen, e. r. moscardi, andj. r. anderson. 1979.economic training manual. information bulletin no. 27. cimmyt, mexico. 5 p. roy, r. k. and k. s. p. singh. 1986. response of pop-corn (zea mays) to plant population and nitrogen. indian j. agron. 31(1): 87-92. senanayake. l., d.p. knievel, s.e. stevena. 1987. nodulation and symbiotic nitrogen fixation of cowpea (vigna unguiculata l.). plant and soil 99: 435-439. singh, s.k., s.c. varmaand and r.p. singh. 2004. residual effect of organic and inorganic sources of nutrients in lowland rice on succeeding lentil. indian j. agric. res., 38(2): 121-125 zapata. f., s.k.a. danso, g. hardarson and m. fried. 1987. nitrogen fixation and translocation in field-grown fababean. agron. j. 79: 505-509. bangladesh agron. j. 2019, 22(2): 103-112 bio-economics of different dry direct seeded winter rice based intercropping systems under varying fertilizer management a. akhter1,m.p. anwar1, 2, *, m. begum1, s. yeasmin1, 2, m.i. rabeya1, r. islam3 and a.k.m.m. islam1,2 1department of agronomy, bangladesh agricultural university, mymensingh-2202 2agro innovation laboratory, department of agronomy, bangladesh agricultural university, mymensingh-2202 3department of seed science and technology, bangladesh agricultural university, mymensingh-2202, bangladesh *corresponding e-mail: parvezanwar@bau.edu.bd (received: 19 february 2020, accepted: 26 february 2020) keywords: aerobic rice, leafy vegetable, intercropping, fertilizer requirement, yield,benefit cost ratio abstract the experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh during february to june 2017 to study the feasibility of different direct seeded rice based intercropping systems under varying fertilizer management. the experiment was conducted in afactorialrandomized complete block design with three replications. four leafy vegetables viz., gimakalmi, indian spinach, red amaranth andjute were intercropped with dry direct seeded boro rice (cv. brri dhan28) following three fertilizer dose such as 100, 75 and 125% of recommended fertilizer, and sole rice was also maintained as control. rice yield was the highest (3.87t ha-1) in sole cropping, and intercroppingresulted insignificant rice yield reduction. although inintercropping rice yielddecreased, but increased both gross margin and benefit cost ratio (bcr) as compared to rice sole cropping. among the vegetables, gimakalmi performed the best followed by red amaranth in terms of yield and 125% recommended fertilizer was the best fertilizer dose. gimakalmi intercropped with rice following 125% recommended fertilizer showed the highest gross return and bcr (2.53). therefore, vegetables like gimakalmi and red amaranth couldbe recommended as intercrop with dry direct seeded winter rice with 125% recommended fertilizer for better productivity and higher economicreturn. introduction among field crops, rice is most widely grown under irrigated condition requiring about 50% of the total amount of water diverted for irrigation, which itself accounts for 80% of the amount of fresh water consumed(farooq et al., 2009). dry direct seeding rice is considered as a water saving technology having some advantages over puddled transplanted system (humphreys et al., 2005; zhao et al., 2007; anwar et al., 2012; rahman, 2019).if winter rice is grown following dry direct seeded system, 40-60% irrigation water (compared with traditional flood irrigated system) could be saved (anwar et al., 2010; rahman et al., 2017; arefinet al., 2018). in dry direct seeded system, rice is direct seeded on dry soil and moisture content of rice field is kept around or below field capacity. fortunately, field condition of dry direct seeded rice is favorable for growing different vegetables as intercrop. therefore, intercropping in direct seeded rice with vegetables may be considered as a viable option to maximize productivity and economic return (rabeyaet al., 2018). in intercropping system, proper use of fertilizer is very important to ensure the maximum harvest of both main and intercrop. optimum rate of fertilizer plays a vital role in growth and development of rice plant(miah et al., 2017; sarkeret al., 2018; jahanet al., 2018). rice growth is remarkably hampered 104 akhter et al. when fertilized with lower dose which drastically reduces yield. potential yieldof a crop can be achieved only when the nutrients are applied at optimum dose which is required by the crop plants.on the other hand, excessive fertilization encourages excessive vegetative growth which makes the plant susceptible to insect, pest and diseases and ultimately reduces yield. so, it is essential to find out the optimum rate of fertilizer application for better productivity and higher economic return of rice vegetable intercropping systems. but no work has so far been done on this aspect. the present study was thereforeconducted to evaluate the productivity and profitability of different dry direct seeded winter rice based intercropping systems under varying fertilizer levels, and to optimize fertilizer requirement for this system. materials and methods the experiment was carried out at the agronomy field laboratory, bangladesh agricultural university, mymensingh(24°75´ n latitude and 90°50´ e longitude and at an altitude of 18 m), during february to june 2017. the experimental field was medium high land under the agro-ecological zone of old brahmaputra floodplain (aez-9).the field was medium high land having well-drained silty loam floodplain soil with ph 6.8.the average air temperature, rainfall (monthly total), relative humidity (monthly average) and sunshine hours (monthly total) during the experimental period ranged from 22.1-28.8°c, 0.20–496.1 mm, 74.7–84.9% and 97.8–191.6 hr.,respectively.the experiment included 2 factors; factor a: intercropping systems (5)such as (i) rice (sole), (ii) rice + gimakalmi, (iii) rice + indian spinach, (iv) rice + red amaranth, (v) rice + jute,and factor b: fertilizer management (3)such as (i) 100% of recommended fertilizer (rf)for rice, (ii) 75% rf, (iii) 125%rf.sole leafy vegetable plots ofgimakalmi, indian spinach, red amaranth and jute were also maintained only for calculating land equivalent ratio.the experiment was laid out in afactorial randomized complete block design (rcbd) with three replications. the unit plot size was 4.0 m × 4.0 m. a brief description of the crop varieties used in this experiment is given in table 1. table 1.characteristics of the crop varieties crop cultivar/ variety days to harvest yield (t ha-1) developed/ marketed by rice (oryza sativa) brri dhan28 133-136 5-6 brri gimakalmi (ipomoea reptans) evergreen 25 20-30 40-45 metal seed ltd. indian spinach (basella alba) read leaf 35-40 20-25 metal seed ltd. red amaranth (amaranthuscruentus) altapeti-20 30-35 9-10 lalteer seed ltd. jute (corchoruscapsularis) cvl-1 30-35 7-8 bjri brri = bangladesh rice research institute, bjri = bangladesh jute research institute the land was dry ploughed followed by harrowing and leveling without puddling to obtain a smooth seedbed. recommended fertilizer dose were 300, 125, 80, 80 kg ha-1 of urea, triple super phosphate, muriate of potash and gypsum (100%), respectively. all fertilizers except urea were applied as basal dose. urea was top dressed in three equal splits at 15, 30 and 45 days after sowing (das). the plots were fertilized as per treatments. sprouted rice seeds were sown on 13 february 2017 in75 cm wide alternate strip in each plot. red amaranth, jute, gimakalmi, indian spinach were seeded as intercrop between two rice strips. in rice, spacing was maintained as 15 cm×15 cm. jute and red amaranth were broadcast while gimakalmi and indian spinach were sown in line maintaining 25 cm×25 cm and 37.5 cm×15 cm spacing. seed rate used for jute, gimakalmi, indian spinach, red amaranth were 8, 9, 12, 2.5 kg ha-1, respectively. red amaranth and jute seeds were sown twice at the same day of rice sowing and at 35 days after rice sowing. while, gimakalmi and indian spinach were sown once at the same day of rice sowing. a light irrigation was given just after sowing for proper seed germination and better seedling establishment. anothertwo irrigations were given at 30 and 60 das. after every irrigation bio-economics of different rice based intercropping system 105 105 excess water was drained out immediately to avoid damage to vegetables. no major disease infestation was noticed either in rice or in vegetables. only cup 50 ec was sprayed @20 ml10 l-1 water at 40 das to prevent cutworm infestation in vegetables.grain yield was recorded after harvesting the whole plot and was converted to tha-1 (14% moisture content).leafy vegetables were harvested at maturity and fresh weight was taken immediately after harvest and converted to t ha-1.all non-material and material costs constituted the variable cost were considered. eight working hours of a labor was considered as a man-day, irrigation cost, cost of seed, fertilizer cost etc. were included in variable cost. gross return was computed by adding market values of grain yield, straw yield and vegetable yield together. gross margin = gross return–total variable cost… … … … … … … … (i) the relative yield of a crop = ����� �� ��������� ����� ����� �� ���� ���� … … … … … … (ii) rice equivalent yield (for vegetables) = y�+ ���� × ���� �� … … … … … … … (iii) here, yr = yield of rice, pr= sales price of rice, yint = yield of intercrop (jute, gimakalmi, indian spinach and red amaranth), pint = sale price of intercrop land equivalent ratio = ��������� ����� �� ���� ���� ����� �� ���� + ��������� ����� �� ��������� ���� ����� �� ��������� … … … (iv) benefit cost ratio (bcr) = ����� ������ ����� ���� … … … … … … … … … … (v) the collected datawere analyzed using “analysis of variance” technique with the help of computer package, mstat-c, and the significance of themean differences was adjudged by the duncan's multiple range test. results and discussion rice yield parameters among the yield parameters, effective tillers hill-1 and grains panicle-1 were significantly affected by intercropping systems and fertilizer management but 1000-grain weightinsignificant (table 2).intercropping with jute and indian spinach showed no adverse effect on effective tiller and grain production, but with gimakalmi and red amaranth resulted in reduced number of effective tillers hill-1 and grains panicle-1 compared to rice sole culture. both effective tillers hill-1 and grains panicle-1was gradually increased with the increasing level of fertilizer application. rice yield grain yield of rice was significantly affected by intercropping system, fertilizer management (table 2) and their interaction (table 3). highest rice yield was obtained from sole culture and intercropping resulted in significant yield reduction. rice yield was drastically reduced when intercropped with gimakalmi or red amaranth (>46%), while jute and indian spinach intercropping resulted in around 30% yield reduction. results showed that rice yield was increased gradually with the every increment of fertilizer rates which confirms demand of higher than recommended fertilizers while intercropping. among the interactions, sole rice coupled with 125% rf yielded the highest followed by 100 and 75% rf. the lowest grain yield was recorded when gimakalmi was intercropped with rice at 75% recommended fertilizer which was statistically similar to red amaranth intercropped rice following 75% recommended fertilizer. 104 akhter et al. table 2.effect of intercropping systems on yield contributing characters and yield of rice intercropping systems effective tillers hill–1(no.) grains panicle-1(no.) 1000grain weight (g) grain yield (t ha–1) rice sole 8.15a 83.09a 19.23 3.32a rice +gimakalmi 7.167b 79.60b 19.41 1.78d rice +indian spinach 8.02a 82.92a 19.42 2.38b rice + red amaranth 7.22b 80.69b 19.17 1.79d rice + jute 7.76a 83.26a 19.42 2.23c sx 0.14 0.93 0.21 0.03 level of significance ** * ns ** cv (%) 5.81 3.42 3.36 3.64 fertilizer management 100% rf 7.88b 83.34b 19.47 2.44b 75% rf 6.41c 76.55c 19.29 1.74c 125% rf 8.70a 85.85a 19.23 2.72a sx 0.11 0.72 0.16 0.02 level of significance ** ** ns ** cv (%) 5.81 3.42 3.36 3.64 in a column, figures with same letter (s) or without letter do not differ significantly whereas figures with dissimilar letter differ significantly (as per dmrt). ** significant at 1% level of probability, * =significant at 5% level of probability, ns = not significant. vegetable yield intercropping system, fertilizer management andtheir interaction exerted influence on vegetable yield (figure 1, 2 and 3).gimakalmi produced the highest yield closely followed by red amaranth, while indian spinach yielded the lowest. like rice, vegetable yield was increased gradually with the increasing level of fertilizer.among the interactions, the maximum vegetable yield (7.03 t ha-1) was recorded in gimakalmi intercropped with rice at 125% rf which was statistically similar to that of same vegetable grown with 100% rf or red amaranth fertilized with 125%rf. the lowest vegetable yield (0.90 t ha-1)was obtained from indian spinach applied with 75%rf which was statistically similar to those of indianspinach grown with 100% rf or jutewith 75%rf. bio-economics of different rice based intercropping system 105 105 fig. 1. effect of intercropping systems on vegetable yield fig. 2. effect of fertilizer management onvegetable yield 0 1 2 3 4 5 6 7 rice + gima kalmi rice + indian spinach rice + red amaranth rice + jute v eg et a b le y ie ld ( t h a -1 ) intercropping systems 0 1 2 3 4 5 100% recommended fertilizer 75% recommended fertilizer 125% recommended fertilizer v eg et a b le y ie ld ( t h a -1 ) fertilizer management 104 akhter et al. fig.3. yield of vegetables as influenced by intercropping systems and fertilizer management interaction relative yield of rice (ryr) relative yield determines competitive ability of component crops in intercropping system. as shown in table 3, the relative yield of rice ranged from 0.44 to 0.75, which indicates that rice yield loss was reduced by around 60% due to intercropping with different vegetables. the highest yield reduction (63%) with of rice was occurred when gimakalmiwas intercropped with rice following 75% recommended fertilizer. on the other hand, the lowest yield reduction (16%) was recorded in rice sole cropping following 125%recommended fertilizer. table 3.rice yield, vegetable yield, relative yield of rice, equivalent yield and land equivalent ratio of intercropping systemsunder different fertilizer management interaction yield of rice(tha-1) vegetable yield (tha-1) ryr rey (tha-1) ler 100% rf sole rice 3.33b 3.33 1.0 rice + gimakalmi 1.89fg 6.53 0.57 7.33 1.11 rice + indian spinach 2.50d 1.33 0.75 3.83 1.3 rice + red amaranth 2.03f 5.83 0.61 6.89 1.13 jute 2.47d 1.50 0.74 3.97 1.32 75% rf sole rice 2.77c 2.77 1.0 rice + gimakalmi 1.23i 4.90 0.44 5.31 0.97 rice + indian spinach 1.87g 0.90 0.66 2.77 1.28 rice + red amaranth 1.33i 4.53 0.48 5.11 1.02 rice + jute 1.53h 1.20 0.55 2.73 1.15 125% rf sole rice 3.87a 3.87 1.00 rice + gimakalmi 2.23e 7.03 0.58 8.09 1.09 rice + indian spinach 2.77c 1.87 0.72 4.64 1.28 rice + red amaranth 2.03f 6.63 0.52 7.56 1.05 rice + jute 2.70c 2.13 0.70 4.83 1.26 0 1 2 3 4 5 6 7 8 gima kalmi indian spinach red amaranth jute v eg et a b le y ie ld ( t h a -1 ) intercropping systems × fertilizer management 100%rf 75%rf 125%rf bio-economics of different rice based intercropping system 105 105 rice equivalent yield (rey) table 3 showed that highest rice equivalent yield (8.09 t ha-1) was obtained from gimakalmiintercropping following125% rf, while the lowest one (2.73 t ha-1) was observed in jute intercropping following 75% rf. although relative yield of rice was lower than sole crop in every case, but intercropping resulted in higher yield advantage over the sole rice cropping ranged from 18.0 to 142.9%. land equivalent ratio (ler) land equivalent ratio (ler) was recorded more than 1 for all the intercropping systems except rice + gimakalmi intercropping with75% rf (table 3). the ler >1 confirms the advantages of intercropping as compared to sole cropping, while ler < 1 indicates a disadvantage of intercropping. the highest ler of 1.32 (jute + rice following100% rf) means an intercrop benefit of 0.32. on the contrary, gimakalmi + rice intercropping following 75% rf resulted in the lowest ler of 0.97 with an intercrop loss of 0.03. cost benefit analysis total variable cost, gross return, gross margin and benefit cost ratio (bcr) of different rice vegetable intercropping systems are presented in table 3. total variable cost was less in sole rice cropping following 75% rf than that of other intercrop combinations. the highest total variable cost was calculated (tk.100850 ha-1) for gimakalmiintercropped with rice following 125% rf because of higher fertilizer dose. the total variable cost for red amaranth and jute were tk.98525 ha-1and tk.92675 ha-1 at 100%rf, respectively. indian spinach, on the other hand resulted in the lowest total variable cost of tk.90325ha-1 due to less seed rate and only onetime sowing. data showed that the lowest gross return was calculated in sole rice. among the intercrop species, gimakalmiintercropped with rice resulted in the highest gross return (tk.166550 ha-1 to tk.255300 ha-1) because of highest yield. on the contrary, rice intercropping with jute resulted in the lowest gross return (tk. 90750ha-1) as well as gross margin (tk. 2400 ha-1) in jute-rice intercropping system following 75%rf(table 4). among the intercrop species, gimakalmiintercropped with rice resulted in the highestgross margin(tk.154450ha-1) at 125%rf. the highest (2.53) benefit-cost ratio(bcr) was obtained from gimakalmiintercropped with rice following125%rf. second highest bcr (2.39) was obtained from red amaranth intercropped with rice following125%rf. the lowest bcr (1.03)was found in rice intercropping with jute following 75%rf. all the yield contributing characters except 1000-grain weight were significantly affected by intercropping systems. similar to tillering ability, intercropping with gimakalmior red amaranth adversely affected the yield contributing characters of rice. rice grain yield was significantly reduced in all the intercropping systems but with gimakalmior red amaranth resulted in drastic yield reduction because of the poor performances of yield parameters.reduction in rice productivity due to intercropping has also been reported by many others (singh et al., 1996; rabeyaet al., 2018). rice yield reduction was mostly the consequence of reduced number of effective tillers hill-1 and grains panicle-1 and increased number of non-effective tillers hill-1. as reported by many researchers (ahmad, 1990; saleemet al., 2000),suppressive effect of intercrop species on rice growth and yield attributes was the consequence of inter-specific competition for limited resources during early growth stage and also the incompetence of rice plants to recuperate that loss at later stages. the drastic reduction in rice productivity due to intercropping with gimakalmior red amaranth was mostly the outcome of luxuriant growth and shading effect of those vegetables on rice at early growth stage. yield of vegetables varied widely and this was happened due to the differences in their yield potential and competitive abilities with rice. fertilizer management showed tremendous influence on growth, yield parameters and yield of rice, and all the parameters were gradually improved with the increasing fertilizer rates. irrespective of intercropping system, rice yield was the highest when fertilized with 125% recommended fertilizer. even sole rice yield also was increased with the increased fertilizer rates which indicates the poor fertility status of the experimental soil, and also confirms that the recommended fertilizer rate was not 104 akhter et al. enough for the experimental field or study area. mbahet al. (2007) observed that system productivity of the soybean-maize intercropping was increased with the increasing level of fertilizers. usman et al. (2015) also reported similar findings from their study. although different intercropping systems resulted in substantial rice yield losses, but the system productivity was increased. this might be the consequence of more efficient uses of resources due to varying plant architecture and growth duration of the component crops (oroka and omoregie, 2007). rabeyaet al. (2018)also reported similar findings from their study done at the same location with same intercropping systems. competitive behavior and aggressivity of intercrop component are mostly responsible for the yield reduction of main crop (sullivan, 2001; muonckeet al., 2007). therefore, selection of intercrop species is very crucial for maximizing the system productivity. all the intercropping systems yielded higher than rice sole-cropping in terms of rice equivalent yield in this study. increase in rice equivalent yield due to intercropping has also been reported earlier (joshi, 2002; jabbaret al., 2010).land equivalent ratio (ler) were also recorded>1 for all the intercropping systems (except for gimakalmifertilized with 75% rf) which endorses the advantages of intercropping over sole cropping of rice. differences in the yielding ability among vegetable species might be responsible for the variation in ler among different intercropping systems (rabeyaet al., 2018). higher bio-efficiency in terms of ler in intercropping has also been documented by many researchers (oroka and omoregie, 2007; ogutuet al., 2012). all the intercropping systems resulted in higher net return and benefit cost ratio than rice sole cropping. these results are in conformity with those of many researchers (saleemet al., 2000; rabeyaet al., 2018). this might be due to the higher yield along with higher market price of vegetables compared to those of rice. table 4. cost and return analysis of rice-leafy vegetable intercropping systems under differentfertilizer management interaction gross return (tk. ha-1) total variable cost (tk.ha-1) grossmargin (tk.ha-1) bcr 100% rf sole rice 117550 84925 32625 1.38 rice + gimakalmi 231450 99575 131875 2.32 rice + indian spinach 129050 90325 38725 1.43 rice + red amaranth 218000 98525 119475 2.21 rice + jute 133100 92675 40425 1.44 75% rf sole rice 98100 80600 17500 1.22 rice + gimakalmi 166550 95250 71300 1.75 rice + indian spinach 93750 86000 7750 1.09 rice + red amaranth 160800 94200 66600 1.71 rice + jute 90750 88350 2400 1.03 125% rf sole rice 136750 86200 50550 1.59 rice + gimakalmi 255300 100850 154450 2.53 rice + indian spinach 154350 91600 62750 1.69 rice + red amaranth 238150 99800 138350 2.39 rice + jute 160050 93950 66100 1.70 present study confirms the viability of cultivating leafy winter vegetables as intercrop with dry direct seeded winter rice. it is also evident that rice-vegetable intercropping results in better productivity and higher economic return compared to rice sole cropping. based on the present findings, gimakalmi or red amaranth could be suggested as potential intercrop component of dry direct seeded winter rice. however, further site specific studies considering other agronomic and fertilizer requirement of dry direct seeded rice-leafy vegetable intercropping system aspects are necessary. hence, it deserves further investigation to formulate the fertilizer package for different dry direct seeded rice-leafy vegetable intercropping systems. bio-economics of different rice based intercropping system 105 105 conclusion findings of the present study confirm the feasibility of intercropping leafy vegetables especially gimakalmi and red amaranth in dry direct seeded boro rice.although intercropping diminished rice yield, but increased both gross marginand benefit cost ratioas compared to sole rice cropping. among the vegetables,gimakalmiperformed the best followed by red amaranth in terms of yield with 125% recommended fertilizer dose. therefore, rice intercropping withgimakalmi following 125%recommended fertilizer could be practiced for higher profitability. acknowledgement authors thankfully acknowledge the financial grant provided by the ministry of science and technology, government of the people’s republic of bangladesh for the project under special allocation for science and technology 2016-2017. references ahmad, h.k. 1990. studies on biological intercrop relationship and water use techniques in wheat. phd thesis, department of agronomy, university of agriculture, faisalabad, pakistan. anwar, m.p., a.s. juraimi,a. man, a. puteh, a. selamatandm. begum. 2010. weed suppressive ability of rice (oryza sativa l.) germplasm under aerobic soil conditions. aust. j. crop sci. 4: 706–717. anwar, m.p., a.s.juraimi, a. puteh, a. selamat, m.m. rahman and b. samedani. 2012. seed priming influences weed competitiveness and productivity of aerobic rice. actaagr. sc. and b-s p. 62(6):499-509. doi: 10.1080/09064710.2012.662244. arefin, m.a., m.r. rahman, a.n.m.a. rahman, a.k.m.m. islam and m.p. anwar. 2018. weed competitiveness of winter rice (oryza sativa) under modified aerobic system. arch. agr. environ. sci. 3(1): 1-14. doi: 10.26832/24566632.2018.030101. farooq, m., s.m.a. basra, n. ahmad andg.murtaza. 2009. enhancing the performance of transplanted course rice by seed priming. paddy water environ. 7: 55-63.doi: 10.1007/s10333-008-0143-9. humphreys, e., c. meisner, r. gupta, j. timsina, h. beecher, t.y. lu, y.s. yadvinder-singh, m. gill, i. masih, z.j. guoandj. thompson. 2005. water saving in rice-wheat systems. plant prod. sci. 8:242–258. doi: 10.1626/pps.8.242. jabbar, a., r. ahmad, b.i. hussain, z.a. virk ands.n. vains. 2010. effect of different rice-based intercropping systems on rice grain yield and residual soil fertility. pak. j. bot. 42: 2339–2348. jahan, n.a., s. yeasmin, m.p. anwar, m.a. islam, h. rahman and a.k.m.m. islam. 2018. efficacy and economics of different need based nitrogen management approaches in winter rice. am. j. plant sci. 9:2601-2611. doi: 10.4236/ajps.2018.913189. joshi, m. 2002. dynamics of rice-based cropping systems in the southern transitional zone of karnataka, india.intl. rice res. 27: 41–42. mbah, e.u., c.o. muoneke and d.a. okpara. 2007. effect of compound fertilizer on the yield and productivity of soybean and maize in soybean/maize intercrop in southeastern nigeria. trop. subtrop. agroecosyst. 7: 87-95. miah, h., m.p. anwar, m.r. rahman, s. hoshain and k. hossen. 2017. minimizing nitrogen requirement of rice through foliar spray of urea. imperial j. interdisc. res. 3(12): 244-254. muoneke, c.o., m.a.o. ogwuche and b.a. kalu. 2007. effect of maize planting density on the performance of maize/soybean intercropping system in a guinea savannah agro ecosystem. afr. j. agric. res.2: 667–677. 104 akhter et al. ogutu, m.o., h. ogola, j.n. okechandn. kidula. 2012. rain fed rice-legume based cropping systems for sustainable food security and incomes for the small-scale farmers. east afr. agric. forest. 78: 179– 188. oroka, f.o. and a.u. omoregie. 2007. competition in a rice–cowpea intercrop as affected by nitrogen fertilizer and plant population. sci. agri. 64: 621–629.doi:10.1590/s0103-90162007000600010. rabeya, i.m., m.p. anwar,m.m. rahman,a. akhter anda.k.m.m. islam. 2018. intercropping of dry direct seeded boro rice with leafy vegetable for better weed suppression and higher profitability. fundam. appl. agric. 3(3): 545-558.doi: 10.5455/faa.302642844. rahman, a.n.m.a., a.k.m.m. islam, m.a. arefin, m.r. rahman and m.p. anwar. 2017. competitiveness of winter rice varieties against weed under dry direct seeded conditions. agril. sci. 8:1415-1438. doi: 10.4236/as.2017.812101. rahman, m.m. 2019. potential benefits of dry direct seeded rice culture: a review. fundam. appl. agric. 4(2):744-758.doi: 10.5455/faa.16534. saleem, m.f., s.h. shah, m.a. malik and m.k. munir. 2000. bio-economics of different upland rice-based intercropping systems under strip plantation. int. j. agric. biol.2: 294–296. sarker, d., m.p. anwar, m.r. uddin and k. hossen. 2018. exploring the possibility of using agroplusbiodecomposer for boosting up rice productivity under bangladesh condition. fundam. appl. agric. 3(1): 372–381. doi: 10.5455/faa.284983. singh, g., o.p. singh,m. kumar, a.l. rajput ands. maurya. 1996. effect of intercrops on yield and economics, weeds and pest infestation of deep-water rice. annu. agric. res.17: 14–17. sullivan, p. 2001. intercropping principles and production practices.university of arkansas, fayetteville, usa. usman, m., m.g. nangere and i. musa. 2015. effect of three levels of npk fertilizer on growth parameters and yield of maize-soybean intercrop. int. j. sci. res. 5(9): 2250-3153. zhao, c., h. jiang, c. ren, y. yin and y. li. 2007.studies on key techniques of sowing rice directly on dry land for high yield and high efficiency.j. jilin agril. sci.32: 9–11. bangladesh agron. j. 2019, 22 (1): 1-6 effect of soil test based fertilizer package for yield and economic return of lentil + mustard mixed cropping system in charland of pabna m. maniruzzaman1*, m. robiul alam2, m.s. islam3, m.z. islam1, m.s.h. molla4 and m.a. islam5 1scientific officer, 2senior scientific officer, 3principal scientific officer, ofrd, bari, pabna, 4senior scientific officer, ofrd, bari, rangpur, and 5scientific officer, ofrd, bari, shampur, rajshahi corresponding e-mail: maniruzzaman.bari@yahoo.com (received: 21 december 2017, accepted: 16 september 2019) keywords: mixed cropping, char land, lentil, mustard, lentil equivalent yield, economic return abstract the experiment was conducted at char sadipur the char land of pabna during the rabi season of 2013-14 and 2014-15 to determine appropriate fertilizer dose for enhancing production and economic return from lentil+ mustard mixed cropping system. the experiment was laid out in a randomized complete block design with 3 dispersed replications. eight soil test based fertilizer packages viz.,t1: n20 p24 k20 s18 zn2 b1.5, t2: n25 p24 k20 s18 zn2 b1.5, t3: n25 p30 k20 s18 zn2 b1.5, t4: n25 p24 k25 s18 zn2 b1.5, t5: n20 p30 k25 s18 zn2 b1.5, t6: n25 p30 k25 s18 zn2 b1.5, t7: n15 p18 k15 s14 zn1.5 b1kg ha -1kg ha-1 and t8: native nutrient (control) were tested for lentil + mustard mixed cropping system. soil test based n25 p30 k25 s18 zn2 b1.5 (t6) showed better performance on crop growth and yield of lentil and mustard in lentil+ mustard mixed cropping system in both the year. the highest lentil yield 0.70 t ha-1 in 2013-14 and 0.95 t ha1 in 2014-15 was obtained from soil test based n25 p30 k25 s18 zn2 b1.5 (t6). similarly, maximum lentil equivalent yield (1233 kg ha -1in 2013-14 and 1280kg ha-1 in 2014-15) was also obtained from the same treatment. the maximum gross margin (tk. 31639 ha-1 in 2013-14 and tk. 32480 ha-1 in 2014-15) was recorded from soil test based n25 p30 k25 s18 zn2 b1.5. so, application of soil test based fertilizer increases lentil and mustard yield as mixed crop as well as income of the farmers. introduction in bangladesh the lands of char area are not suitable for all crops and all seasons. in pabna, there is a vast area of char land under aez-11. nutrient status of char land is poor due to coarse textured soils, low water holding capacity, low nutrient content, river bank erosion and flooding. farmers of char land in pabna generally grow lentil and mustard as mixed crop where they use local variety with no or limited fertilizers. for this reason, the yield of lentil and mustard in this region is much below than that of potential yield level. balanced fertilization can play a major role to enhance the present yield level. experimental evidences reveal that the crop is highly responsive to different fertilizers and its yield can be increased remarkably through the judicious fertilization (bari, 1988; mohamed,1984; roy and singh, 1986; kazi et al., 2002). fertilizer recommendation solely based on crop response data often fails to show economic viability. in this context, perrin et al. (1979) reported that response of yield should be supported by economic evaluation for judicious fertilizer recommendation. since the application of optimum dose of fertilizer is important for increasing the yield of lentil and mustard mixed cropping system, about:blank 6 maniruzzaman et al. but very limited information in this regard is available in bangladesh, the present study was undertaken to determine the optimum fertilizer dose of lentil and mustard mixed crop in char land. materials and methods the experiment was conducted at char land of char sadipur areas of pabna during rabi season of 2014-15 to 2015-16. the experimental site was in gopalpur soil series belonging to the high ganges river floodplain soils (aez11). before starting the experiment, initial composite soil samples (0-15 cm depth) were collected from the experimental plots and were analyzed. the analytical result indicated that soil was sandy loam with very low organic matter content (0.82%) and slightly alkaline in nature. n content of soil was very low and p, s and zn content of the soil were low. k content of the soil was medium (table 1). table 1. nutrient status of the initial soil sample (0-15cm depth) of experimental plots at char sadipur, pabna soil properties values interpretation soil ph 8.1 slightly alkaline organic matter content (%) 0.82 very low total n (%) 0.05 very low available p (μg/g soil) 11.3 low available s (μg/g soil) 9.2 low available zn (μg/g soil) 0.57 low exchangeable k (meq%) 0.17 medium eight treatments consisted of t1: n20 p24 k20 s18 zn2 b1.5 (stb), t2: n25 p24 k20 s18 zn2 b1.5, t3: n25 p30 k20 s18 zn2 b1.5, t4: n25 p24 k25 s18 zn2 b1.5, t5: n20 p30 k25 s18 zn2 b1.5, t6: n25 p30 k25 s18 zn2 b1.5, t7: n15 p18 k15 s14 zn1.5 b1kg ha -1and t8: native nutrient (control that is without fertilizer). the experiment was laid out in randomized complete block (rcb) design with three replications. the unit plot size was 5m x 4m.the land was prepared by power tiller and laddering. after completion of land preparation, the entire amount of all fertilizers was applied as per treatment specification. the seeds of lentil and mustard were broadcasted in each plot on 10 november in 2013-14 and 15 november in 2014-15 maintaining the same ratio of 80:20 for lentil + mustard mixed crop in both the season. two times weeding were done at vegetative stage for better growth of the crops. rovral 50 wp @ 2.5 g l-1 was applied 3 times at 7-10 days interval from flowering until pod formation to control stem phylum disease of lentil. other intercultural operations were done when required. mustard was harvested on 5 february in 2013-14 and 10 february in 2014-15 while lentil was harvested on 23 february in 2013-4 and 27 februaryin 2014-15 cropping season. other intercultural operations were done when required. necessary data on days to flowering, days to maturity, yield and yield contributing characters were collected and analyzed through statistical analytical package with mstat c software. the productivity of mixed cropping system was estimated by calculating their lentil equivalent yield (ley) using formula given by ahlawat and sharma(1993), where cost and return analysis of different treatments were done for gross margin. soil test based fertilizer package 5 results and discussion plant height and yield contributing characters of lentil in lentil + mustard mixed cropping system have been presented in table 2a. significant variation in plant height, no. of pods plant-1, no. of seed pod-1, and 1000-seed weight were observed-in different treatments. the highest plant height (27cm and 30.7cm) was measured from n25 p30 k25 s18 zn2 b1.5 (t6) treatment, which was significant irrespective of years and the lowest plant height (20.1cm and 21.87cm) was measured in t8 (control). in case of number of seeds pod-1there was no significant difference among the treatments except t4 and control in 2013-14 and only control in 2014-15 cropping season. higher 1000-seed weight was observed from t6, t5, t4 and t2 but t5 was not higher in 2013-14 and the lowest 1000-seed weight (24.83g and 18.07g)-from control (t8). performance of t3 regarding yield contributing parameters is poor though n and p level was used in higher dose compare to other treatments might be due to lower dose of k. char land soil is light textured soil and contain very low n, p, k, s, zn and b. for that application of higher dose of n, p and k show higher growth and yield contributing characters. this results are supported by anonymous (2009) as it reported that application of n, p, b and rhizobium inoculum significantly enhanced the positive growth and yield parameters of lentil. table 2a. plant height and yield contributing parameters of lentil in lentil + mustard mixed cropping system at char sadipur, pabna during the rabi season of 2013-14 and 2014-15 treatment plant height (cm) no. of pods plant-1 no. of seed pod-1 1000seed weight (g) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 t1 24.43 de 23.17 c 26.90 bc 30.00bcd 1.83 ab 1.70abc 19.40 b 25.17 bc t2 26.40 bcd 24.57bc 27.00 bc 36.33 ab 1.83 ab 1.70abc 20.13 a 25.67 ab t3 27.73 abc 24.47bc 31.33 ab 34.60abc 1.83 ab 1.70abc 19.63 b 25.00 bc t4 28.90 ab 25.07 b 31.00 ab 29.57 cd 1.90 a 1.63 bc 19.93 ab 25.67 ab t5 25.43 cd 24.03bc 32.63 ab 30.40bcd 1.93 a 1.70abc 20.73 a 25.50 bc t6 30.70 a 27.00 a 38.33 a 38.40 a 1.90 a 1.76 a 20.80 a 26.33 a t7 23.80 de 23.47bc 23.47 bc 26.73 de 1.80 ab 1.73 ab 18.63 bc 25.33 bc t8 21.87 e 20.10 d 20.30 c 21.63 e 1.70 b 1.60 c 18.07 c 24.83 c cv(%) 6.51 4.03 18.34 12.47 4.89 4.30 3.50 1.80 t1: n20 p24 k20 s18 zn2 b1.5 (stb), t2: n25 p24 k20 s18 zn2 b1.5, t3: n25 p30 k20 s18 zn2 b1.5, t4: n25 p24 k25 s18 zn2 b1.5, t5: n20 p30 k25 s18 zn2 b1.5, t6: n25 p30 k25 s18 zn2 b1.5, t7: n15 p18 k15 s14 zn1. 5b1 kg ha -1and t8: native nutrient (control) yield of lentil and mustard in mixed cropping system have been presented in table 2b. in 2014-15 maximum stover yield of lentil (0.75 t ha-1 and 0.79 t ha-1) was found from n25 p30 k25 s18 zn2 b1.5 (t6) treatment, which was statistically similar to t5 and t3 while minimum stover yield 0.31 t ha -1 from control (t8). in 2013-14, the maximum stover yield was observed from the treatment n25 p30 k25 s18 zn2 b1.5 (t6) followed by t5, t4 and t3 and the minimum stover yield was found from the control treatment which was statistically similar to the treatment t7 (table 2b). however, the highest seed yield 0.95 t ha -1 was attained from n25 6 maniruzzaman et al. p30 k25 s18 zn2 b1.5 (t6) which was significantly higher than other treatments in 2014-15 cropping season but in 2013-14 cropping season, the highest seed yield (0.70 t ha-1) was found from the treatment t6 which was statistically similar with t5, t4 and t3. on the contrary, control (t8) treatment provided the lowest lentil yield (0.41 t ha-1 and 0.21 t ha-1). the cumulative contribution of potential yield traits might be the reason for higher seed yield from n25 p30 k25 s18 zn2 b1.5 (t6). in contrast, poor crop growth and yield traits resulted in the lowest seed yield in control (t8). maximum lentil yield increased (132% and 233%) over control was obtained from n25 p38 k31 s18 zn3 b1.5 (t6) in 2014-15 and 2013-14 respectively. the overall results indicate that in char land conditions soils are dominated with sand particles and low organic matter which causes deficiency in nutrient availability in soil and make imbalance in subsequent plant uptake. therefore, 100% fertilizer package plus 25% additional nutrients specially n,p and k that is fertilizer dose n25 p30 k25 s18 zn2 b1.5 enhance optimum plant growth and development and higher yield in lentil. anonymous (2009) reported that balanced application of n, p, k, s, zn and b significantly increased the yield of lentil over control. the results obtained in this experiment are supported by the findings of mondal et al. (2010); bhuiyan et al. (2008) and singh et al. (2004) found that yield of lentil increases when fertilizer was applied as soil test based. in case of mustard as mixed crop, similar trend was observed as lentil in both the season. the maximum mustard seed yield (0.38 t ha-1 and 0.66 t ha-1) was recorded from n25 p30 k25 s18 zn2 b1.5 (t6). the exclusion of fertilizer that is control (t8) plot resulted in the lowest seed yield (table 2b). the seed yield of lentil is higher in second year than first year while the seed yield of mustard is higher in first year than second year. it might be due to mixed cropping by which two crops sharing their yield that is when one crop performs better then another crop could perform poor. bhowal et al. (2014) also found that when lentil perform better then mustard’s performance was not good enough in mixed cropping system. table 2b. stover yield, seed yield of lentil and mustard in lentil + mustard mixed cropping system at char sadipur, pabna during the rabi season of 201314 and 2014-15 treatments stover yield of lentil (t ha-1) seed yield of lentil (t ha-1) seed yield of mustard (t ha-1) % yield increase of lentil over control (t8) 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 t1 0.41 c 0.51 bc 0.43 cd 0.73 b 0.25 d 0.20 cd 105 78 t2 0.45 c 0.55 bc 0.47 bc 0.74 b 0.28 d 0.22 bcd 124 80 t3 0.60 b 0.63 ab 0.56 abc 0.78 b 0.38 c 0.23 bc 167 90 t4 0.60 b 0.61 b 0.56 abc 0.74 b 0.51 b 0.25 b 167 80 t5 0.66 b 0.65 ab 0.61 ab 0.75 b 0.46 bc 0.26 b 190 83 t6 0.79 a 0.75 a 0.70 a 0.95 a 0.66 a 0.38 a 233 132 t7 0.33 cd 0.45 cd 0.38 d 0.60 c 0.25 d 0.19 d 81 46 t8 0.23 d 0.31 d 0.21 e 0.41 d 0.06 e 0.04 e cv(%) 13.36 13.82 19.20 8.64 15.98 24.51 t1: n20 p24 k20 s18 zn2 b1.5 (stb), t2: n25 p24 k20 s18 zn2 b1.5, t3: n25 p30 k20 s18 zn2 b1.5, t4: n25 p24 k25 s18 zn2 b1.5, t5: n20 p30 k25 s18 zn2 b1.5, t6: n25 p30 k25 s18 zn2 b1.5, t7: n15 p18 k15 s14 zn1.5 b1 kg ha -1and t8: native nutrient (control) however, maximum lentil equivalent yield (1280 kg ha-1 and 1233 kg ha-1) was found from n25 p30 k25 s18 zn2 b1.5 (t6) which is 355% and 176% higher over control in 2013-14 and 2014-15 cropping season, respectively while minimum lentil equivalent yield (271 kg ha-1and 463 kg ha-1) was found from control (t8) soil test based fertilizer package 5 plot (table 2c). the results of this experiment indicate that soil health in char land is relatively poor which does not provide proper nutrient backup to the crops. due to having very low organic matter and plant nutrition, higher rate of fertilizer management results in higher crop yield. table 2c. lentil equivalent yield and % increase of lentil equivalent yield over control in lentil+ mustard mixed cropping system at char sadipur, pabna during the rabi season of 2013-14 and 2014-15 treatments lentil equivalent yield (kg ha-1) % lentil equivalent yield increase over control (t8) 2013-14 2014-15 2013-14 2014-15 t1: n20p24k20s18zn2b1.5 641 913 137 97 t2: n25p24k20s18zn2b1.5 705 939 160 103 t3: n25p30k20s18zn2b1.5 878 994 224 115 t4: n25p24k25s18zn2b1.5 971 966 258 109 t5: n20p30k25s18zn2b1.5 991 986 266 113 t6: n25p30k25s18zn2b1.5 1233 1280 355 176 t7: n15p18k15s14zn1.5b1 585 771 116 67 t8: control 271 463 economic return from lentil + mustard mixed cropping cost and return analysis demonstrated that gross margin (tk.32480 ha-1 and tk.31639 ha-1) was obtained from n25 p30 k25 s18 zn2 b1.5 (t6) in 2014-15 and 2013-14, respectively followed by t4 and t5 fertilizer management packages (table 3). probably higher production and gross return (tk.83200 ha-1 and tk.80145 ha-1) from this t6 treatments resulted in higher economic return. negative gross margin was recorded from control (t8) in both the year but t1, t2 and t3 in 2013-14 cropping season due to poor yield from those treatments and gross return which was lower than the total variable cost. table 3. cost and return analysis of lentil + mustard mixed cropping system influenced by fertilizer packages at char sadipur, pabna during the rabi season of 2013-14 and 2014-15 treatments gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 t1 59345 41665 49670 47367 9675 -5682 t2 61035 45825 49870 47565 11165 -1740 t3 64610 57070 50560 48346 14050 8724 t4 62790 63115 50030 47725 12760 15390 t5 64090 64415 50520 48308 13570 16107 t6 83200 80145 50720 48506 32480 31639 t7 50115 38025 47620 45278 2495 -7253 t8 30095 17615 41540 39010 -11445 -21395 t1: n20 p24 k20 s18 zn2 b1.5 (stb), t2: n25 p24 k20 s18 zn2 b1.5, t3: n25 p30 k20 s18 zn2 b1.5, t4: n25 p24 k25 s18 zn2 b1.5, t5: n20 p30 k25 s18 zn2 b1.5, t6: n25 p30 k25 s18 zn2 b1.5, t7: n15 p18 k15 s14 zn1.5 b1 kg ha -1and t8: native nutrient (control) market price (tk kg-1 ): lentil: grain=65.00 1, straw=5.00, mustard: grain=45.00 1, straw=1.00 6 maniruzzaman et al. conclusion the findings could be concluded that fertilizer packages exerted significant effect on yield and yield attributes of lentil and mustard in mixed cropping system. soil test based fertilizer n25 p30 k25 s18 zn2 b1.5 showed better performance on crop growth and yield of lentil and mustard as mixed cropping system in char land of pabna. the maximum economic return in terms of gross return and gross margin was also recorded in the same fertilizer package. references ahlawat, i.p.s. and r.p. sharma. 1993. agronomic terminology, indian society of agronomy, new delhi, india, 3rd edition. bari (bangladesh agricultural research institute). 1988 annual report for 1988, joydebpur, gazipur-1701, bangladesh. pp.215-218. bhowal, s.k., m.m.u. chowdhury, m.s. bhuiyan, a.h.m.a. faisal, i.s.m. farhad and s.k. bhowmik. 2014. yield and yield attributes of lentil (lens esculenta) as ab mixed crop with mustard (brassica campestris). sci. agri. 8(2): 76-79. bhuiyan, m.a.h., d. khanam, n.e. ali, m.k. zaman and m.s. islam. 2008. response of lentil to bio fertilizer and chemical fertilizers in the farmer’s field. annual research report, 2007-2008, soil science division, bari, gazipur.pp.36-39. kazi, b. r. 2002. effect of irrigation frequencies on growth and yield of soybean. 2(6): 661-662. kumar, s. and m.singh. 2009. 25 years of pulses research at iipr, 19842009. indian institute of pulses research, kanpur 208024, india.pp.6265. mohamed, s. a. 1984. effect of irrigation water and fertilization on yield and water use efficiency of corn plants in fayoum governorate. moshtohor, egypt annual agril. sci. 20(2): 221-235. mondal, r.h., b. anwar, m. rafiuddin and m.a. hossain. 2010. integrated nutrient management for sustaining soil fertility and yield of lentilmungbean-t. aman cropping pattern. annual research report, 20092010, pulses research centre, gazipur.pp. 82-86. perrin, r. k., winkelmen, d.l., moscardi, e.r. and anderson, j.r. 1979. economic training manual. information bulletin no. 27. cimmyt, mexico. p.5 roy, r.k. and k.s. singh. 1986. response of pop-corn (zea mays) to plant population and nitrogen. indian j. agron. 31(1): 87-92. singh, s.k., s.c. varma and r.p. singh. 2004. residual effect of organic and inorganic sources of nutrients in lowland rice on succeeding lentil. indian j. agric. res. 38(2): 121-125. in the world, rice (oryza sativa l) is the major source of of food for more than 2 bangladesh agron. j. 2016, 19(2): 115-123 ankuri technology for seed germination and seedling emergence of rice in cold environment tahmid hossain ansari and montasir ahmed bangladesh rice research institute, regional station, rajshahi corresponding author: tahmidhansari@yahoo.com key words: ankuri germination, rice seed germination, seedling emergence, tray seedling, zagmethod abstract rice seed germination as well as seedling emergence in cold environment is a challenge for successful rice cultivation during dry (boro) season in northern bangladesh experiments were conducted in two consecutive boro seasons in rajshahi to develop techniques for improving germination and seedling emergence under cold conditions.. seeds of rice var. brri dhan29 and brri dhan50 were germinated following the traditional “zag-method” and separately in a frame covered with air tight heat insulating plastic tripal (called ankuri germinator). then vapor therapy was given inside ankuri and maintained 25350c with high humidity. external and internal temperatures of ankuri were recorded. seed germination was checked at 12 h interval. in another experiment, germinated seeds of brri dhan29 were sown on soil in trays followed by light irrigation. one set of trays was placed in ankuri. another two sets of trays were placed in the field with polythene covered and uncovered. similar experiment using non-germinated dry seed was also conducted. vapor therapy was applied in ankuri only in and trays were checked regularly to observe the plumule and radicle growth. the germination rate (%) of the tested varieties in ankuri ranged from 82-96% which was 6492% in zag-method. high variation of germination in zag-method was due to improper temperature and humidity during the zag period. seed germination was faster in ankuri which was observed within 2.5 days. this was also 2.5 days earlier in comparison with the zag-method. soaking period ranged 22-24 h outside in cold water/weather. but 18 h soaking in ankuri resulted good germination. irrespective of varieties, the growth was 5.4 and 1.7 times more respectively for plumule and radicle in ankuri than zag-method. seedling emergence was 2-3 days earlier in both dry and soaked/germinated seeds sown in trays of ankuri than the outside polythene covered trays. seedling emergence failed in open-trays. average air temperature from 18:00-9:00 was cooler (150c) than 9:00-18:00 period (150c). ankuri maintained 25-350c and high humidity which favored seed germination and seedling growth. therefore, ankuri could be an effective seed germination technique with faster germination, radicle and plumule growth. introduction rice is considered as the staple food crops in bangladesh, a sub-tropical country producing 34.7 million metric tons covering from 80% of the total cultivated area (bbs, 2015). yield loss due to low temperature are well documented in japan (shimono et al., 2007), korea, india, nepal, bangladesh and other countries (kaneda and beachell, 1974; lee 2001). in the dry season, a large part of bangladesh especially in the northern part is generally affected with low temperature. this cold environment affects seed germination, seedling raising and transplanted seedling establishment. low temperature reduces germination (basnayake et al., 2003; ali et al., 2006) and cause poor establishment (sasaki 1979 1981; lewin and maccaffery 116 ansari et al. 1985; shimono et al., 2002, 2004, 2007). ali et al. (2006) reported the effects of genotypes and physiological age of rice seeds on germination under low temperature in bangladesh. a high percentage of seed germination is an important criterion for successful rice cultivation. in bangladesh, farmers obtain their seed from a wide range of sources, because of the unavailability of adequate quantities of good quality seed for raising seedling. therefore, the quality of seed generally varies considerably, which results in poor or no germination in low temperature or cold environment. farmers are germinating these kinds of seed following traditional zag-method. poor germination or even germination failure is a general scenario in this practiced method because of improper temperature and humidity during zag (incubation)-period in dry season. thus the zag-method in association with low temperature during dry season hampers or affects seed germination. therefore, attempts have been taken to develop a germination technique for better rice seed germination as well as seedling emergence in tray during cold period. material and methods the experiments were conducted at bangladesh rice research institute (brri), regional station, rajshahi during the dry (boro) seasons 2012-13 and 2013-14. a seed germination chamber was developed where rice var. brri dhan29 and brri dhan50 seeds were tested for germination in both the years. further, seedling emergence in trays was also tried in the second season only. development of germination chamber in the first season, a germination chamber was developed using angle-bar, screw, plastic tripal, foam and electric appliances like electric ware, plug etc. in such a way that seed can be germinated and seedlings in trays can be raised through vapor therapy with controlled temperature and high humidity. the hypothesis was that the seed germination and raising seedlings could be possible through continuous supply of vapor therapy inside the chamber maintaining proper temperature and humidity. investigation on seed germination after the development of the seed germination chamber called “ankuri”, the performance of ankuri for seed germination was tested in two consecutive seasons. seeds were soaked for 22-24 h in first season and 18 h in second season. then the seeds were divided into two parta and kept in the moist cloth bag separately and rapped with moist sac. one part was preserved following the zag-method and another part in the ankuri. then vapor therapy was given to boost up the temperature and humidity inside ankuri in such a way that the temperature could be maintained 25350c with high humidity. temperature of both outside and inside ankuri was recorded at three h interval starting from 6 h to 21/24 h. germinating seed samples were checked at 24 h interval for 2 days and then 12 h interval until the sprouting observed. seed sampling was done from each replicated samples of rcb design keeping consideration of both inner and outer side effect of the seed bag. the germinated and non germinated seeds were counted and percent germination was calculated. the length of plumule and radicle was also measured from randomly selected 10 seedlings in each replication. the germination percentage was calculated using the formula germination (%)= (number of seed germinated/total number seeds tested) × 100 117 ankuri technology for seed germination and seedling emergence of rice in cold environment seedling vigor index= (average of plumule length + average of radicle length) × germination percentage. raising seedling in trays ankuri germinated seeds were shown on the pulverized soil in trays following tray seeding method. the seeds were sown in the trays at 120 g per tray for brri dhan29. fifteen trays were prepared and soaked by sprinkler. one set of three trays covered with polythene was kept outside (open field) and another set of three trays was kept open at field adjacent to the polythene covered trays. moreover, nine trays were kept in the ankuri where vapor therapy was given in such a way that the temperature could be maintained 25-350c with high humidity. the trays were checked every 12 h interval to observe the seedling emergence. the trays were taken out from ankuri and kept outside with polythene cover when the sprouted young seedling was attained 2-3 mm in length. statistical analysis all the collected data were analyzed by using cropstat package developed by irri. results and discussion development of ankuri the design of the germination chamber ankuri is shown in figure 1. the length was 120 cm., the width was 90 cm and the height was 120 cm. there were few tray holding levels or stares each differed by 25 cm. two electric heaters were prepared using different sizes nut screws in an electric fiber board (7.5 cm × 2.5 cm inch). two screws were used in each electric heater. the sizes of the screws were 0.35 cm / -2.5 cm and 1 / -4 cm, respectively for the energy expenditure 200 w/h and 275 w/h. both the screws were connected with electric wares and attached with electric power by a plug. the mini heater was placed in a bowl filled with 15 l water inside the ankuri. all the heaters tested separately for 24 hours. vapor generation was investigated and the temperature inside the ankuri was recorded during testing period (table 1). table 1. specification of screws and their electric consumption in ankuri sl. no. screw size screw type power consumption (wh) temperature range in ankuri (0c) vapour generation 1. 0.35 cm 2.5 cm nut screw 200 21.2 37.3 observed very slow 2. 1-4 cmnut screw 275 25.0 40.0 observed slow the mini electric heater (200 w/h) made of 0.35 cm/ -2.5 cm screw was considered good for seed germination and tested further for temperature during seed germination. during seed germination both outside and inside temperatures of ankuri was recorded at an interval of 3 h from 6:00 am to 9:00 pm. the temperature inside the ankuri ranged from 21.2-37.30c and the outside temperature was recorded as 9.0-30.00c (table 2). using this technique, seed germination was done successfully as compared to the zag method (fig. 2, table 2). 118 ansari et al. fig. 1. ankuri seed germination chamber fig. 2. zag-method for seed germination table 2. air and ankuri temperature during seed germination hour temp. (0c) 2013 temp. (0c) 2014 air ankuri air ankuri 6:00 9.0 21.2 15.3 25.0 9:00 14.1 27.7 23.1 30.0 12:00 22.4 31.3 34.6 37.3 15:00 21.3 29.1 30.0 33.8 18:00 15.1 27.3 21:00 18.3 35.2 figures are averages of five observations investigation on seed germination the germination percentages of the tested varieties are shown in table 3. the percentage of germination ranged from 72-92% in zag-method which was 85-96% in ankuri in the first season. here, significant difference in the percentage of seed germination was observed in the case of brri dhan50 but insignificant in brri dhan29.however, both the varieties showed a large difference in seed germination in the second season that ranged from 64-75% in zag-method in compare with the ankuri-method (82-91%). table 3. germination (%) of dry (boro) season varieties in zag and ankuri methods. variety* year (january) germination (%) lsd (0.05) zag-method ankuri-method brri dhan29 2013 92 96 4.56 brri dhan50 72 85 8.23 119 ankuri technology for seed germination and seedling emergence of rice in cold environment brri dhan29 2014 75 91 8.26 brri dhan50 64 82 15.04 *seed sourcebrri, rajshahi during the germination period, temperatures of both outside and inside was measured which indicated that air temperature was lowest at 6:00 am and highest at 12:00 noon (table 2). air temperature increased gradually from morning to noon and then decreased to 150c at 6:00 pm in 2013. on the other hand, the temperature of ankuri ranged from 21.20c to 31.30c in 2013 and 25.00c to 37.30c in 2014. in 2014, air temperature at 6:00 am and 9:00 pm were 15.30c and 18.30c corresponding to the ankuri temperature 25.00c and 37.30c, respectively. the effect of treatment i.e., germination method on sprouting period was highly significant. on the other hand, both plumule and radicle lengths was also different (table 4). table 4. effect of germination methods on sprouting period, plumule and radicle growth irrespective of varieties in the dry season, 2014. germination method asprouting time (hour) plumule length (mm) radicle length (mm) zag-method 120 0.43 4.66 ankuri-method 60 2.32 7.93 lsd (0.05) 0.36 1.40 2.98 figures are averages of 6 observations aall the replicated samples germinated in the same period in each germination method the effect of variety irrespective of methods was similar (table 5). data shows that the radicle growth of brri dhan29 was better (1.4 times) than the brri dhan50 with almost same growth of plumule (1.30-1.46). table 5. effect of varieties on sprouting period, plumule and radicle growth irrespective of germination methods in the dry season, 2014. variety asprouting time (hour) plumule length (mm) radicle length (mm) brri dhan29 90 1.30 7.43 brri dhan50 90 1.46 5.16 lsd (0.05) ns ns ns figures are averages of six observations aall the replicated samples germinated in the same period in each germination method the interaction effect of variety and germination methods shows a great difference in sprouting period irrespective of variety and germination methods (table 6). again, significant different in plumule and radicle length was also found. the seedling vigor index value was high in ankuri germinated seeds compared to zag-method (table 7). table 6. interaction effect of varieties and germination methods on sprouting period, plumule and radicle growth in the dry season, 2014. variety germination method asprouting time (hour) plumule length (mm) radicle length (mm) brri dhan29 ankuri 60 2.13 10.05 zag 120 0.46 4.80 brri dhan50 ankuri 60 2.52 5.80 120 ansari et al. zag 120 0.39 4.52 lsd (0.05) 0.51 1.98 4.21 figures are averages of 3 replications aall the replicated samples germinated in the same period in each variety and germination method table 7. interaction effect of seedling vigor of boro varieties in the dry season, 2014. variety treatment seedling vigor index brri dhan29 ankuri 1108.7 zag 394.8 brri dhan50 ankuri 682.0 zag 314.2 lsd (0.05) variety × treatment ns raising seedling in trays figure 3 and figure 4 shows the scenario of seedling emergence in trays in ankuri. seedling emergence was the best in ankuri followed by polythene covered trays kept outside in the field. but seed germination was failed in the trays kept in open field. seedling emergence was faster in ankuri compare to polythene covered outside trays (pcot). the growth of seedlings was better in ankuri compare to the pcot. the seedlings were not affected with disease in ankuri. qualitative evaluation of ankuri germinated seeds showed faster germination as well as good quality seedling (table 8). 121 ankuri technology for seed germination and seedling emergence of rice in cold environment fig 3. seedling emergence of brri dhan29 in ankuri trays fig. 4. seedling emergence of brri dhan29 in polythene covered trays. table 8. qualitative score of emerged seedling in trays in the dry season, 2014 treatment emergence germination rate seedling quality tray seedling (ankuri) complete emergence faster germination good (++) tray seedling (polythene covered) partial emergence slow germination moderate (+) tray seedlings (open field) no or very poor emergence no or very late germination bad (-) ++ indicates good growth of seedling + indicates moderate growth of seedlings compare to ankuri treated seedlings indicates very poor or no growth of seedlings development of simple seed germination chamber is important in the changing climate environment. seed germination is poor in low temperature (sipaseuth et al., 2007) and the farmers are practicing traditional zag-method that cannot be ensured good seed germination. because, farmers prepared the zag-environment in different ways with their own experience with available materials they find e.g., rice straw, jute sac, bamboo made basket etc. this method cannot maintain proper temperature and humidity during germination period. as a result, farmers failed to get good germination in the used seed even if it is good quality seed. the low quality seed is again at high risk for germination in zag-method as this cannot maintain proper temperature and humidity. in some cases, farmers keep their seed for germination in rice straw-mass which sometimes produce high vapor with higher temperature that cause the seed even boiled and finally failure of germination. therefore, climate resilient and farmers’ friendly seed germination chamber could be an alternative for good seed germination in low temperature during dry season. ankuri maintained the temperature ranged from 250c to 350c with a few exceptions that could be minimized. this can also generate high humidity (around 98%). the temperature and high humidity mentioned above in the ankuri is favorable for rice germination. therefore, ankuri could be the alternative option for good seed germination. a comparative advantages and disadvantages between ankuri and zag-method are listed in the table 9. 122 ansari et al. table 9. comparative results of ankuri and zagmethods for seed germination. sl. no. ankurimethod zagmethod 1. soaking period 22-24 h (18h is enough if seeds are soaked in ankuri). soaking period 22-24 h. 2. seeds are sprouted first in 24 h after soaking. seeds are sprouted first in 72 h after soaking. 3. seeding can be done after 60 h i.e., 2.5 days. seeding can be done after 120 h i.e., 5.0 days. 4. germination rate is always higher. germination rate is lower. 5. germination is ensured. not so reliable. 6. possibility of seed infection is less due to less time needed in preservation. possibility of seed infection is comparatively high. 7. easy to follow the method. difficult to follow the method. 8. temperature and humidity can be controlled. difficult to control temperature and humidity. 9. helpful for tray seedling raising. not applicable. 10. cost is comparatively high. no extra cost is required. 11. seed can be saved (av. 13% in the expt.) that will mitigate seed crisis a lot. no such advantage. both the varieties showed higher percentage of seed germination in ankuri as compared with the zag-methodbecause of the maintenance of proper temperature and humidity in the ankuri. the probability of receiving low temperature during decemberjanuary in the northern and south-western part of bangladesh has been prevailing in the last few years. seedling mortality or failure of raising seedling at that time has become a general scenario in those areas during dry season. the results of this study showed that zag-method produced lower germination especially due to improper lower temperature. this result is inconsistent with the others who reported that temperature below 110c reduce the rate of germination by 10-22% (ali et al., 2006) and 100c caused germination failure in most asian rice growing areas (matsushima et al., 1968; tajima et al., 1983; lee, 2001; ali et al., 2006). in 2013, there was no difference in percent seed germination in brri dhan29 which showed the significant difference in 2014. the zag-method applied in these experiments was done inside the building room. probably the temperature was maintained well during zag period but the building room environment is not available at farmers’ level. therefore, risk in zag-method at farmers’ level is always inevitable. the plumule and radicle length which is the component of seed vigor are associated with seed germination also. plumule length was much higher in ankuri than zagmethod at p=0.05and the radicle length was 70% more in the same ankuri method. these indicate that the germination method influence the seed germination even with same seed vigor. therefore, zag-method can affect the quality seed for germination, plumule and radicle growth and thereby seed vigor. in the case of ankuri, vapor induced temperature and humidity successfully overcome the low seed germination, plumule and radicle growth i.e., quality seed and even farmers’ saved seed can successfully be used for germination in ankuri comparatively with zag-method. the ankuri technique could also be used irrespective of the variety. all the parameters like percent germination, plumule growth and radicle growth showed similar results irrespective of variety with few exceptions. these were observed when no interaction effect was found in radicle and plumule growth irrespective of variety and germination method except for brri dhan50 in zagmethod. in the raising of seedling in trays, the better growth was also observed in the ankuri treated trays seedling. the seed vigor index was higher in ankuri treated seed due to higher germination percentage, plumule and radicle growth at p=0.05. the variation in temperature might have influence in good germination and the growth of plumule and radicle. however, 123 ankuri technology for seed germination and seedling emergence of rice in cold environment there is no interaction effect of variety and treatment in this method. it means, ankuri significantly contribute to promote seed germination with higher vigorous seedlings. conclusion the experiments clearly demonstrated the efficacy of ankuri in rice seed germination as well as the weakness of the traditional zag-method. therefore, ankuri could be an effective germination technique which influenced faster germination and higher plumule as well as radicle growth. it can also be used for raising seedling in trays as well. commercial exploitation and adoption of this technology at farmers’ level could minimize seed loss ensuring germination and economic benefit. references ali, m. g., r. e. i. naylor and s. mathews 2006. distinguishing the effect of genotype and seed physiological age on low temperature tolerance of rice (oryza sativa l.) expt. agric. 42: 337-349. basnayake, j., v. sihathep, p. sonekham, m. senthonghae, v. sibounheuang, v. phamixay, m. chanphengxay and s. fukai. 2003. effects of time of planting on agronomic and yield performance of several rice cultivars under various temperature condition in lao pdr. in: proceedings of the 11th agronomy conference. melbourne, 1-6 february (www.regional .org.au/au/asa/2003/). bbs (bangladesh bureau of statistics). 2015. statistical pocketbook bangladesh 2015. bangladesh bureau of statistics, statistics and informatics division (sid), ministry of planning, govt. of the people's republic of bangladesh. april 2016. pp. 499 kaneda, c. and h. m. beachell. 1974. response of indica-japonica rice to low temperature. sabro j, 6: 17-32. lee, m. h. 2001. low temperature tolerance in rice: the korean experience in: fukai s, basnayake j (eds), acair proceedings 101: increased low–land rice production in the mekong region. australian centre for international agricultural research, gpo box 1571, canbera, act 2601, pp. 138-146 lewin, l. and d. maccaffery. 1985. rice seedlings growth is influenced by water depth and temperature. farmers’ newsl. large area 127. shimono, h., t. hasegawa, k. iwama. 2002. response of growth and grain yield in paddy rice to cool water at different growth stages. field crops res, 73: 67-79 shimono, h., t. hasegawa, s. fujimura, k. iwama. 2004. response of leaf photosynthesis and plant water status in rice to low water temperature at different growth stages. field crops res, 89: 71-83 shimono, h., h. okada, e. kanda, i. arakawa. 2007. low temperature induced sterility in rice: evidence for the effects of temperature before panicle initiation. field crops res, 101: 221-231. sipaseuth, j. basnayake, s. fukai, t.c. farrell, m. senthonghae, sengkeo, s. phamixay, b. linquist and m. chanphengsay. 2007. opportunities to increasing dry season rice productivity in low temperature affected areas. field crops res, 102: 87–97. 124 ansari et al. sympson, g. m. 1990. seed dormancy in grasses. cambridge university press, u.k. tarima, k., a. amemiya, n. kabaki. 1983. physiological study of growth inhibition in rice plant as affected by low temperature ii. physiological mechanism and varietal difference of chilling injury in rice plant. bull national institute of agricultural science, vol 34, pp. 69-111. wu, r. and a. garg. 2003. engineering rice plant with trehalose producing genes improve tolerance to drought, salt and low temperature. seed quest, isb news report, march 2003. department of molecular biology and genetics, cornell university, usa. (www.seedquest.com/news/release/2003/march/5456 htm). http://www.seedquest.com/news/release/2003/march/5456 bangladesh agron. j. 2019, 22 (1): 95-104 effect of nutrient management on growth and yield of cauliflower hybrids in haor area m. salwa1* and m.a. kashem2 1research associate, department of soil science, sylhet agricultural university, sylhet -3100 2professor, department of soil science, sylhet agricultural university, sylhet -3100 corresponding e-mail: p.salwa5716@gmail.com (received: 24 august 2019, accepted: 17 october 2019) keywords: hybrid, fertilizer, growth, yield, cauliflower, haor abstract the experiment was conducted in the dekarhaor of noagaon village under south sunamganj upazila of sunamganj district during november 2017 to february 2018 to observe the effect of nutrients management on growth and yield of cauliflower hybrids. two hybrids namely shiragiku (v1) and rupali (v2), and four combinations of nutrients, viz. (i) recommended rate of n-p-k-szn-b @ 180-80-180-28-4.5-2.1 kg ha-1(f1), (ii) f1 + 25% n-p-ks-zn-b of f1 (f2), (iii) f1 – 25% n-p-k-s-zn-b of f1 (f3), and (iv) cow dung @ 10 t ha-1 (f4) was conducted in a factorial randomized complete block design (rcbd) and replicated thrice. plant height (cm), numbers of leaves plant-1, leaf length (cm) and leaf breadth (cm), and spreading diameter (cm) were collected at 15 days intervals, while the yield data were recorded at harvest. the parameters were significantly varied due to hybrids and fertilizers packages. higher gross yield (42.52tha-1) was found in shira giku and lower (42.12 t ha1) from rupali. higher curd yield of 25.17 t ha-1 was obtained in shira giku than rupali (9.61 t ha-1). the highest gross yield of 44.45 t ha-1 was obtained when the crop was treated with cowdung @ 10 t ha-1 followed by recommended fertilizer rate (f1). the curd yield of 18.19 t ha -1 was obtained with 25% less than recommended fertilizer rate of application (f3). the highest gross yield of 52.93 t ha-1 was obtained in v1f1 combination and the lowest of 30.10t ha-1in v2 f1. results revealed that the hybrid shiragiku with recommended dose of fertilizer (180-80-180-28-4.5-2.1 kg ha-1n-p-k-s-zn-b) performed the best in comparison to other treatment combinations. introduction cauliflower (brassica oleracea lin.) is one of the popular cole crops (botrytis group) belonging brassicaceae family (or cruciferae) in bangladesh. the optimum temperature for cauliflower withstands is 10 to 15 ◦ c (din et al., 2007). the yield of cauliflower is low due to lack of proper management practices and nutrients deficiency in the soil. national production of cauliflower was 268.48 thousand mt from 19.424 thousand ha (bbs, 2016). haor with their unique hydro-ecological characteristics are large bowl shaped floodplain depressions. the haor goes under flooding (5-10 m) from late april to october in sunamganj district. in haor areas of north-eastern districts of bangladesh only one crop i.e. boro rice is widely practiced. due to flash flood and longtime inundation of low land of haor areas it is almost impossible to cultivate more than one crop. short duration vegetables can be introduced in that region of medium high land (kanda land). there is a huge scope in haor areas for vegetable cultivation through intensification and diversification of technology in the medium high land during winter. as the haor areas remain under water upto late october, about:blank 96 salwa et al. cauliflower would be a promising crop for that region. after recession of flood water, cauliflower and other winter vegetables could be grown easily. appropriate fertilizer management would play an important role in plant growth and curd formation especially in haor soil. ali et al. (2009) reported that fertilizer manure enhanced curd yield and yield attributes substantially. utilization of organic matter has been well documented to improve physical, chemical and biological properties of soil (whalen et al., 2000; tejada and gonzalez, 2003). but the farmers of haor area are not habituated of cauliflower cultivation with proper fertilizer management of the crop. hence, an experiment was undertaken to select asuitable hybrid of cauliflower and appropriate nutrient management package for increasing productivity of the crop in the haor areas of sunamganj. materials and methods the experiment was conducted in the dekar haorareas of south sunamganj upazila in sunamganj district, during november 2017 to february 2018. two hybrids viz. shiragiku (v1) and rupali (v2), and four combinations of nutrients viz. (i) recommended dose of fertilizer (frg, 2012) (f1) (391:388:391:156:12.8:18.6 kg ha -1 as urea, tsp, mop, gypsum, znso4, borax), (ii) f1 + 25% of f1 (f2), (iii) f1 25 % of f1 (f3), and (iv) cowdung @ 10 t ha -1 (f4) was conducted in haor area. the experiment was laid out in a factorial randomized complete block design (rcbd) with three dispersed replications. the soil of the area was silt-loam in texture having ph 4.9 5.2. experimental fields were medium high land with well drained condition. the unit plot size was 5 m 4 m with 50 cm 50 cm plant spacing. the seedlings were transplanted in the nursery bed from seed bed at a height of 3 cm for proper growth and development. afterwards thirty-day old seedlings were transplanted in the main field on 11th november 2017. the whole amount of tsp, zn and b was applied as basal during the final land preparation. urea and mop were applied in three equal splits at 15, 30 and 45 dat in ring method under moist soil condition and mixed thoroughly with the soil. irrigations were done after fertilizer application and when necessary. three weeding were done to control weeds at 20, 40 and 50 days after planting (dap). insects were controlled successfully by hand picking, removal of damaged leaves and spraying malathion 57 ec @ 2ml l-1 water. yield related data on curd diameter (cm), gross yield (t ha-1) and curd yield (t ha-1) were recorded during harvesting. cauliflower was harvested when attained marketable maturity. harvesting was done at 2-3 days interval up to second week of january 2018. data were converted into t ha-1. the data were analyzed using r software and means separation were adjudged by using dmrt (gomez and gomez, 1984). nutrient management of cauliflower 97 results and discussion growth performance plant height cauliflower hybrids showed significant variation in plant height at 30, 45 and 60 days after planting (dap) (table 1). shira giku attained higher plant height of 21.33, 22.83 and 29.34 cm at 30, 45 and 60 dat, respectively. rupali produced shorter plant of 18.67, 18.75 and 24.58 cm at corresponding dap. significant variation of plant height was found due to application of different nutrients packages. at 15 and 30 dat, the highest plant height of 22.00 and 22.83 cm, respectively, was observed when the plants received recommended dose (f 1 ) of nutrients. at 60 dat, the longest plant (30.03 cm) was found in f 2 treatment. the main causes of above result may be the presence of available n and b in chemical fertilizer comparing sole application of cowdung. in combination, the highest plant height of 27.33 cm at 30 dat was recorded in v 1 f4 and the lowest of 16.33 cm in v2 f 3 . plant height of cauliflower and broccoli showed a significant variation with increasing concentrations of n and p (sharma et al., 2002). number of leaves plant-1 number of leaves plant-1 was higher (6.06) in shiragiku and lower (5.17) in rupali at 30 dap (table 1). ara et al. (2009) reported similar results in respect of plant height. at 30 dap, the highest leaves plant-1 (6.45) was produced from recommended fertilizer package. interaction effect of hybrid and fertilizer showed nonsignificant variations in leaf number. leaf length hybrids showed significant variations in leaf length at 30, 45 and 60 dap (table 2). hybrid shiragiku showed longer leaves of 26.37, 36.00 and 38.99 cm at 30, 45 and 60 dap, respectively. rupali produced the shorter length of 17.48, 24.27 and 27.87 cm at the corresponding dates. significant variation on leaf length was found due to application of different fertilizer packages. the maximum length of 24.87 cm at 30 dap was due to recommended fertilizer treatment (f1) which was statistically similar to f 2 and f3 packages. similar pattern was also showed at 45 dap. the biggest leaf was of17.73 cm given by v 2 f 2 at 15 dap and the smallest in v2 f 4 . according to farahzety and aishah (2013), leaf area was increased up to 33 % by using chemical fertilizer. due to fertilizer application the increased cell elongation and cell division probably influenced the leaf growth of cauliflower. leaf breadth significant variations were observed in leaf breadth at 30 and 45 dap. hybrid shiragiku produced wider leaf breadth of 12.75 and 17.65 cm at 30 and 45 dap, respectively while the narrower leaves of 9.67 and 13.54 cm were observed in rupali in the corresponding dap (table 2). statistically significant variations on leaf width were observed due to different packages of nutrients application. the treatment f2 produced the maximum leaf of 8.40 cm at 15 dap and the minimum was of 5.57 cm in f 4 . recommended fertilizer treatment (f 1 ) produced the highest leaf breadth of 13.40, 17.78 and 21.98 cm at 30, 45 and 60 dap, respectively. interaction effects showed the significant response of 21.83 cm at 45 dap due to v 1 f 1 combination. 102 salwa et al. spreading diameter higher spreading diameter was reported in case of shiragiku of 17.24, 42.39, 56.28 and 62.10 cm and lower in rupali of 15.93, 34.31, 47.25 and 52.92 cm at 15, 30, 45 and 60 dap, respectively (table 3). at 15 dap, spreading diameter was found significant variation. the highest diameter (17.75 cm) was found due to recommended fertilizer (f 1 ) application and the lowest (15.23 cm) in f 4 treatment. significant variation in spreading diameter was also recorded at 30 dap where the highest value (45.47 cm) was showed due to f 2 package and the lowest (32.03 cm) was reported in f 4 package. the results were corroboratory towards the haor soil condition and nutrient availability due to different fertilizer packages. the interaction effects of hybrids and fertilizers showed non-significant variation in spreading diameter. yield contributing characters of cauliflower curd diameter higher curd diameter (48.33 cm) was produced in shiragiku, while lower (38.46 cm) in rupali (table 4) and the difference in the response was probably due to genetically improved, nutrients uptake capacity and adaptive nature of the hybrids. fertilizer packages had significant variation on curd diameter. the maximum curd diameter (46.67 cm) was recorded with the recommended nutrient application, (f1) which was at par with f 4 (43.42 cm), while the lowest diameter (41.33 cm) in f3. the largest curd diameter (59.00 cm) was observed in v1 f 1 and the smallest one (34.33 cm) in v 2 f 1 (table 4). curd size has a positive response towards the proper fertilizer application (rikiand kristian, 1997). gross yield gross yield was non-significant between the hybrids as well as different fertilizers packages (table 4). it was probably caused due to profuse vegetative growth with seasonal effects as well as fertility. the highest gross yield of 52.93 t ha -1 was obtained in v 1 f 1 and the lowest 30.10 t ha-1in v 2 f 1 . according to stanislaw and jan (1998) gross yield of cauliflower increased with nitrogen rates up to 600 kg ha1. curd yield higher curd yield of 27.17 t ha-1was observed in shiragiku and the lower of 9.61 t ha-1 in rupali (table 4). the results assumed that shiragiku might be adapted to that area while rupali may be the early hybrid but it was planted during late season which reflected the low yield. the highest curd yield of 18.19 t ha -1 was found in f 3 and the lowest (15.05 t ha-1) in f 4 treatment. significant difference in curd yield was found due to interaction effects of hybrids and fertilizer combination. the highest curd yield (33.20 t ha-1) was produced by v 1 f 1 . the lowest curd yield of 2.87 t ha-1 was recorded from v 2 f 1 combination. similar result was reported by das et al. (2000) where curd yield was higher due to higher inorganic fertilizers application. cost and returns the cost of production varied from tk.177005 to tk. 203673 ha-1. the gross return ranged from tk. 57400 to tk. 664000 for different treatments (table 5). bcr was recorded higher in shiragiku where showed negative in rupali because of small size and deformed curd formation, which might be due to seasonal effect (probably early hybrid). 102 salwa et al. table 1. effect of hybrids, fertilizer packages and their interactions on plant height and number of leaves plant-1 of cauliflower in the haor are treatments plant height (cm) number of leaves plant-1 15 dap 30 dap 45 dap 60 dap 15 dap 30 dap 45 dap 60 dap hybrids shira giku 20.75 12.33a 22.83a 29.34a 5.83 6.06a 14.00 19.25 rupali 17.75 17.67b 18.75b 24.58b 5.33 5.17b 13.17 16.42 level of significance ns ** * ** ns * ns ns cv% 18.78 10.51 16.85 13.62 18.18 16.82 22.81 19.09 fertilizer packages f1 (fgr, 2012) 22.00a 22.83a 21.33 28.73a 6.00 6.45a 15.17 19.83 f2 (f1 + 25% of f1) 18.67ab 18.38b 20.50 30.03a 6.00 4.89c 12.83 18.33 f3 (f1 25% of f1) 18.83ab 19.38b 21.00 25.58ab 4.67 6.11ab 13.33 18.00 f4 (cowdung @ 10 t ha-1) 17.56b 18.33b 20.33 23.50b 5.67 5.00bc 13.00 15.67 level of significance * ** ns * ns * ns ns cv (%) 18.78 10.51 18.78 10.51 18.18 16.82 18.18 16.82 hybrids ×fertilizer v1f1 21.33 20.43bc 26.67 33.80 5.67 5.56 15.67 20.33 v1f2 21.00 19.10bcd 20.67 33.40 6.33 4.67 13.00 19.67 v1f3 20.33 22.43b 23.33 27.17 5.00 6.67 13.67 21.00 v1f4 20.33 27.33a 20.67 23.00 6.33 7.33 13.67 16.00 v2f1 22.67 16.33d 16.00 23.67 6.33 4.44 14.67 19.33 v2f2 16.33 17.67cd 20.33 26.67 5.67 5.11 12.47 17.00 v2f3 17.33 16.33d 18.67 24.00 4.33 5.56 13.00 15.00 v2f4 14.67 18.33cd 20.00 24.00 5.00 5.56 12.33 14.33 level of significance ns * ns ns ns ns ns ns cv (%) 18.78 10.51 18.78 10.51 18.18 16.82 18.18 16.82 ‘*’ significant at 0.5 %,‘**’ significant at 1 %, ‘ns’ non-significant, v1=shira giku, v2=rupali, f1 -=recommended dose of npkszns, f2 -= recommended dose + 25% npkszns, f3 -= recommended dose25% npkszns, f4 -=cowdung @ 10 t ha -1, dap = days after planting, cv – coefficient of variance nutrient management of cauliflower 102 table 2. effect of hybrids, fertilizer packages and their interactions on leaf length and breadth (cm) of cauliflower in haor area treatments leaf length (cm) leaf breadth (cm) 15 dap 30 dap 45 dap 60 dap 15 dap 30 dap 45 dap 60 dap hybrids shira giku 15.32 26.37a 36.00a 38.99a 7.12 12.75a 17.65a 20.11 rupali 14.97 17.48b 24.27b 27.87b 7.04 9.67b 13.54b 17.74 level of significance ns ** ** ** ns ** ** ns cv% 10.33 18.81 17.91 15.75 12.22 17.91 15.44 14.98 fertilizer packages f1 (fgr, 2012) 16.38 24.87a 33.92 37.02 7.00b 13.40a 17.78a 21.98a f2 (f1 + 25% of f1) 17.45 23.58a 32.41 34.38 8.40a 12.37ab 15.92ab 19.57a f3 (f1 25% of f1) 16.13 22.20a 28.86 33.10 7.37ab 10.87b 15.72ab 19.30a f4 (cowdung @ 10 t ha-1) 10.60 17.07b 25.38 29.22 5.57c 8.20c 12.96b 14.85b level of significance ns * ns ns ** ** * ** cv (%) 10.33 18.81 10.33 18.81 12.22 17.91 12.22 17.91 hybrids × fertilizer v1f1 16.00a 29.20 41.67 42.33 7.37 16.40 21.83a 25.13 v1f2 17.17a 26.53 38.37 39.17 7.67 13.87 17.83ab 21.17 v1f3 16.43a 29.37 36.67 37.67 7.23 12.53 17.83ab 20.37 v1f4 11.67b 20.40 27.33 29.05 6.23 8.20 13.10c 13.77 v2f1 16.77a 20.53 26.17 27.10 6.63 10.40 13.72bc 18.83 v2f2 17.73a 20.63 26.45 26.16 9.13 10.87 14.00bc 17.97 v2f3 15.83a 15.03 21.05 20.67 7.50 9.20 13.61c 18.23 v2f4 9.53b 13.73 23.42 22.45 4.90 8.20 12.81c 15.93 level of significance ** ns ns ns ns ns * ns cv (%) 10.33 18.81 10.33 18.81 12.22 17.91 12.22 17.91 ‘*’ significant at 0.5 %, ‘**’ significant at 1 %, ‘ns’ non-significant, effect of nutrient management of cauliflower 107 v1-=shira giku, v2rupali, f1 = recommended dose of npkszns, f2 = recommended dose + 25% npkszns, f3 = recommended dose 25% npkszns, f4 = cowdung @ 10 t ha -1, dap = days after planting, cv = coefficient of variance nutrient management of cauliflower 104 table 3. effect of hybrids, fertilizer packages and their interactions on spreading area (cm) of cauliflower in haor area treatments spreading diameter(cm) 15 dap 30 dap 45 dap 60 dap hybrids shiragiku 17.24a 42.39a 56.28a 62.10a rupali 15.93b 34.31b 47.25b 52.92b level of significance ** * * ** cv% 5.09 22.31 16.28 12.77 fertilizer packages f1 (fgr, 2012) 17.75a 33.72b 51.95 60.75 f2 (f1 + 25% of f1) 17.48a 45.47a 55.97 60.58 f3 (f1 25% of f1) 15.88b 42.18ab 53.68 57.90 f4 (cowdung @ 10 t ha -1) 15.23b 32.03b 45.45 50.80 level of significance ** * ns ns cv (%) 5.09 22.31 5.09 22.31 hybrids x fertilizer v1f1 17.60 37.47 58.83 71.97 v1f2 18.27 51.87 59.87 63.87 v1f3 16.57 48.07 59.60 61.50 v1f4 16.53 32.17 46.80 51.07 v2f1 17.90 29.97 45.07 49.53 v2f2 16.70 39.07 52.07 57.30 v2f3 15.20 36.30b 47.77 54.30 v2f4 13.93 31.90 44.10 50.53 level of significance ns ns ns ns cv (%) 5.09 22.31 5.09 22.31 ‘*’ significant at 0.5 %, ‘**’ significant at 1 %, ‘ns’ non-significant, v1= shiragiku, v2= rupali, f1 = recommended dose of npkszns, f2 = recommended dose + 25% npkszns, f3 recommended dose 25% npkszns, f4 cowdung @ 10 t ha -1, dap – days after planting, cv – coefficient of variance 10 7 effect of nutrient management of cauliflower 107 table 4. effect of hybrids, fertilizer packages and their interactions on yield of cauliflower in haor area treatments yield parameters curd diameter (cm) gross yield (t ha-1) curd yield (t ha-1) hybrids shiragiku 48.33a 42.52 25.17a rupali 38.46b 42.12 9.61b level of significance ** ns ** cv% 4.17 19.13 23.52 fertilizer packages f1 (fgr, 2012) 46.67a 41.52 18.03 f2 (f1 + 25% of f1) 42.17b 39.58 17.83 f3 (f1 25% of f1) 41.33b 43.75 18.19 f4 (cowdung @ 10 t ha -1) 43.42ab 44.45 15.05 level of significance * ns ns cv (%) 4.17 19.13 23.52 hybrids x fertilizer v1f1 59.00a 52.93a 33.20a v1f2 46.00b 41.44abc 25.04b v1f3 43.83bc 37.32bc 21.63bc v1f4 44.50bc 38.40abc 20.80bc v2f1 34.33e 30.10c 2.87e v2f2 38.83d 50.17ab 14.75cd v2f3 38.33d 37.72bc 10.64d v2f4 42.33c 50.49ab 10.20d level of significance ** ** ** cv (%) 4.17 18.76 23.52 ‘*’ significant at 0.5 %, ‘**’ significant at 1 %, ‘ns’ non-significant, v1= shiragiku, v2= rupali, f1 = recommended dose of npkszns, f2 = recommended dose + 25% npkszns, f3 =recommended dose 25% npkszns, f4 = cowdung @ 10 t ha -1, cv = coefficient of variance 102 salwa et al. table 5. cost of production, gross return, net return and bcr of cauliflower in haor areas treatments cost of production (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) bcr hybrids shiragiku 203673 503400 299727 2.47 rupali 202283 183200 -19083 -1.10 fertilizer packages f1 (fgr, 2012) 212562 360600 148038 1.70 f2 (f1 + 25% of f1) 265703 356600 90897 1.34 f3 (f1 25% of f1) 159422 363800 204378 2.28 f4 (cowdung @ 10 t ha -1) 177005 301000 123995 1.70 hybrids x fertilizer v1f1 208118 664000 455882 3.19 v1f2 243688 500800 257112 2.06 v1f3 181548 432600 251052 2.38 v1f4 190339 416000 225661 2.19 v2f1 207423 57400 -150023 -3.61 v2f2 233993 295000 61007 1.26 v2f3 180853 212800 31947 1.18 v2f4 189644 204000 14356 1.08 note: market price of cauliflower was tk. 20 kg-1, v1shiragiku, v2rupali, f1 = recommended dose of npkszns, f2 = recommended dose + 25% npkszns, f3 = recommended dose 25% npkszns, f4 cowdung@ 10 t ha-1, bcr = benefit cost ratio conclusion results revealed that the cauliflower var. hybrid shira giku performed better with recommended doses of fertilizer (180-80-180-28-4.5-2.1 kg ha -1n-p-k-s-zn-b) during late season. research with more number of short duration late hybrids/ varieties is needed to conduct in haor area for higher production of cauliflower. acknowledgment the authors acknowledged the funding by krishi gobeshona foundation (kgf) for improving livelihoods of haor farming community through participating research. references ali, m.a., m.s.h. molla, m.r. alam, m.a. momin and m.a. mannan. 2009. effect of combinations of chemical fertilizers and poultry manure on the productivity of crops in the cauliflower-stem amaranth− jute pattern. bangladesh j. agril. res. 34(1): 113-121. ara, n., m.o. kaisar, k.m. khalequzzman, h. kohinoor and k.u. ahamed. 2009. effect of different dates of planting and lines on the growth, yield and yield contributing characteristics of cauliflower. j. soil nat. 3(1): 16-19. bbs. 2016. statistical year book of bangladesh 2016, bangladesh bureau of statistics, ministry of planning, bangladesh, government of the republic of bangladesh. dhaka, bangladesh. 10 7 effect of nutrient management of cauliflower 107 din, m., m. qasim, and n.e. jan. 2007. response of different sowing dates on the growth and yield of cauliflower. sarhad j. agric. 23(2): 289-291. farahzety, a.m. and h.s. aishah. 2013. effects of organic fertilizers on performance of cauliflower (brassica oleracea var. botrytis) grown under protected structure. j. trop. agric. fd. sc. 41(1): 15-25. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka 1215. p.3. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research (2 nd ed.). john willey & sons, new york. pp.28-192. riki, v.d.b. and. t.k. kristian. 1997. effects of nitrogen fertilization on growth and soil nitrogen depletion in cauliflower, acta. agriculturae. scandinavica, section b soil plant sci. 47(3): 149-155. stanislaw, k. and r. jan. 1998. effects of irrigation, nitrogen fertilization and soil type on yield and quality of cauliflower. j. veg. crop prod. 4(1): 67-75. tejada, m. and j.l. gonzalez. 2003. effects of the application of a compost originating from crushed cotton gin residues on wheat yield under dry land conditions. eur. j. agron. 19: 357-363. whalen, j.k., c. chang, g.w. clayton and j.p. carefoot. 2000. cattle manure amendments can increase the ph of acid soils. soil sci. soc. am. j. 64: 962 –966. bangladesh agron. j. 2019, 22 (1): 39-45 influence of green manuring crops on dry matter production and soil health improvement i. j. irin1*, p.k. biswas2, m.j. ullah3, t.s. roy4 and m.a. khan5 1phd fellow, dept. of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2,3,4professor, dept. of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 5professor, dept. of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh corresponding e-mail: isratateo@gmail.com (received: 18 april 2019, accepted: 24 august 2019) keywords: green manuring, soil health, nutrient balance abstract the field experiment was conducted at the agronomy farm of sher-ebangla agricultural university to evaluate the impact of different kind of green manures on soil nutrient balance through adding biomass and n,p and k accumulation. green manuring crops were incorporated after in situ cultivation and results showed that, the biomass incorporation increased the n production in soil. the biomass from sesbania rostrata, sesbania aculeata and crotalaria juncea gave the higher dry matter and nutrient status. incorporation of sesbania rostrata and sesbania aculeata added more organic matter and nitrogen to the soil after green manure incorporation than the prior soil. however, the improved soil quality was recorded with s. rostrata and s. aculeata followed by c. juncea and v. unguiculata incorporation as compared to control (no green manure) and other green manuring crops. the nutrient balance of soil after incorporation of different green manuring crops specially s. rostrata, s. aculeata and c. juncea showed positive balance of nutrients than other green manures. introduction soil is fundamental to crop production and constitutes the natural resources that provide mankind the most of its food and nutrients. food production levels of bangladesh will have to increase rapidly without deteriorating soil quality, if the increasing population of bangladesh will feed itself by following a suitable ecofriendly cropping pattern. green manuring crops are one of the effective measures for soil improvement. green manures could have benefits for soil n dynamics by recovering residual mineral n in soil, by fixing n from the atmosphere for leguminous green manures, and thereby contributing to subsequent crop n nutrition. crops legumes are believed to have the potential to enhance yields of subsequent crops through atmospheric nitrogen fixation as well as enhanced mineralization of soil organic n during legume residues decomposition (jenkinson et al., 1985). according to biswas et al. (1996), incorporation of green manuring crop to the soil reduced 50 percent of recommended n-levels of subsequent rice. introducing green manure crops in a cropping pattern are not only improving soil nitrogen quality but also helps to reduce fertilizer cost. after harvesting of boro rice, a large area remains fallow for about 2-3 months. this period could be used to raise green manures without sacrificing main crops. improve soil and crop productivity, integration of legume cover crops in cropping systems is now being highly emphasized among farmers in the tropics (odhiambo et al., 2010). considering the above facts, the present experiment was undertaken to study the feasibility of improving soil quality through green manuring. 44 irin et al. materials and methods the field experiment was conducted at the agronomy farm of sher-e-bangla agricultural university during april june,2015 to evaluate the impact of different kinds of green manures on soil nutrient balance through adding biomass and n,k and p accumulation. the green manure crops viz. deshi dhaincha (sesbania aculeata), african dhaincha (sesbania rostrata), sunnhemp (crotolaria juncea l.), mungbean (vigna radiata), blackgram (vigna mungo), cowpea (vigna unguiculata), ipil-ipil (leucaen aleucocephala) and mimosa (mimosa pudica) were grown for improving soil fertility along with a control (no green manuring crop). the initial soil of the experimental field (0-15 cm) was collected for analyzing physical and chemical properties before setting the experiment. the experiment was laid out in a randomized complete block design with three replications. there were eight different green manuring crops along with a control as treatments having three replications. the experimental plots (except control) were fertilized with 20-17.6-24.9 kg n, p and k ha-1 from their sources of urea, tsp and mop. fifty days-old green manuring crops were incorporated after in situ cultivation. thirty days after incorporation of green manuring crops, the final soil samples of each experimental plot (0-15 cm) was collected for analyzing physical and chemical properties. the collected data were analyzed statistically by using the statistic-10 computer package. the mean comparison of all parameters were done with tukey’s wprocedure (gomez and gomez, 1984). results and discussion fresh biomass fresh biomass was significantly varied among different green manure crops (figure1). the fresh biomass of green manure crops ranged from 20.33 to 35.00 t ha-1. crotalaria juncea produced significantly higher fresh biomass (35.00 t ha-1) that followed by sesbania rostrata (29.33 t ha-1) and sesbania aculeata (28.12 t ha-1). the minimum fresh biomass was noted in vigna mungo (20.33 t ha-1). it was observed that, sesbania rostrata and c. juncea recorded significantly higher fresh biomass compared with s. aculeata during the time. again s. aculeata recorded significantly higher fresh biomass over vigna unguiculata, mimosa pudica and leucaen aleucocephala. singh and shivay (2014) stated that the increased of biomass accumulation of sesbania might be due to its fast and determinate growth habit leading to enhanced biomass incorporation/addition and nutrient availability in soil. khind et al. (1987) opined that, sesbania aculeata could produce 21.1 t ha-1 of green biomass and accumulate about 133 kg n ha1. sanjay et al. (2015) reported that among the summer green manuring crops, dhaincha recorded significantly higher total fresh and dry matter accumulation compared with sunhemp and cowpea in their two consecutive researches. dry biomass the dry biomass of green manuring crops varied significant where the highest dry matter was obtained from crotalaria juncea (5.25t ha-1) followed by sesbania rostrata (5.12 t ha-1) (figure 1). the significantly lowest biomass (2.60 and 2.86 t ha-1) was recorded invigna mungo and vigna radiata, respectively. however, differences in dry biomass between these treatments were statistically significant. becker et al. (1995) was found that the growth of s. rotrasta was more vigorous in the wet season (long day period) than in the dry season. singh (1981) also agreed with the findings and reported that, the most productive green manure crops yielded about 4-5 tha-1 of dry biomass in 50-60 days and cluster bean has generally been less productive than sesbania, sunnhemp, and influence of green manuring crops 41 cowpea in descending order. zaman et al. (1995) opined that in bangladesh condition, 60 days old dhaincha (s. aculeata) plants produced 5.2 t ha-1 dry matters which yielded 135 kg n/ha. it was observed that in case of s. rostrata, s. aculeata and c. juncea dry biomass yield increased rapidly apparently with the age of plant compared to other green manuring crops. this variation of dry biomass yield may be due to individual genetic makeup of the green manuring crop. fig. 1. fresh and dry biomass production of different green manuring crops (se () = 0.20). here, t1=s. aculeata, t2=s. rostrata, t3= c. juncea, t4=v. radiata, t5=v. mungo, t6=v. unguiculata, t7=l. leucocephala, t8=m. pudica soil organic matter incorporation of eight different green manures, some of them increased the soil organic matter from 1.01 % (initial) level to 1.08 %. the highest organic matter (1.08 % & 1.02 %) was found in t2 (s. rostrata) and t1 (s. aculeata), respectively. soil organic matter decreased in control plot along with other green manuring plot due to lack of legumes and slow releasing activities of other green manuring crops. sesbania aculeata and sesbania rostata incorporation in soil increased 1 and 7% organic matter compared to control. higher organic matter and n contents were present because of incorporation of green manures (biswas and mukherjee, 1991). similar results were also observed by mondal et al. (2003). rahman et al. (2013) stated that, after incorporation of dhaincha, the organic matter status of the soils was found slight increase compared to control (organic matter and total n status of soil from dhaincha ranged from 1.42 to 1.58%). sarwar et al. (2017) reported that, both the organic matter content and total nitrogen (%) were increased due to dhaincha incorporation in soil and the amount of organic matter (%) varied from 1.582 to 2.133 before incorporation and 1.995 to 2.271 after incorporation of dhaincha biomass in soil. 0 5 10 15 20 25 30 35 t1 t2 t3 t4 t5 t6 t7 t8 28.12 29.33 35 22.33 20.33 25.66 25.33 21 4.35 5.03 5.3 2.66 2.66 3.86 3.77 2.73 b io m as s p ro d u ct io n ( t h a -1 ) treatments fresh biomass dry biomass 44 irin et al. fig. 2. effect of different green manuring crops on organic matter changes in soil. here, t1=s. aculeata, t2=s. rostrata,t3= c. juncea,t4=v. radiata,t5=v. mungo,t6=v. unguiculata, t7=l. leucocephala,t8=m. pudica total nitrogen total n status of soil ranged from 0.04 to 0.084 %. the results pertaining to total nutrients in soil of legumes treated plot is presented in figure 3. the highest n content of 0.08% was found in t2 (sesbania rostrata) followed by t6 (vigna unguiculata). the lowest n content of 0.03% was obtained for t5 (vigna mungo), which was much lower than its initial soil. the other green manures showed very little increased of total available n in soil. a gradual increasing trend was t2> t6>t7>t8>t3>t1. the lowest n content of 0.041% was obtained from control plot. s. rostrata increased 166 % total nitrogen in comparison to v. mungo and control. these results suggested that green manuring of sesbania would have increased n fertility of soil because of greatest n contents in their biomass. the increase in total n content of soil due to application of organic manure may be attributed to the mineralization of n by organic manure in soil and greater multiplication of soil microbes, which could convert organically bound n to inorganic form. actually plant materials used as a green manure differed in their chemical composition, rate of decomposition and nutrient element released to the soil. other studies have also reported that green manure legumes contain substantial amount of n and other nutrients. rinaudo et al. (1983) reported that n2 fixed by sesbania rostrata was about 267 kg n ha-1, one third was transferred to the crop and two third to soil. mann et al. (2000) reported that sesbania incorporated plot increased soil n (0.60%) from initial soil (0.48%). onim (1986) reported that sesbania can fixed upto 250 kg n ha-1 in six month. palaniappan (1990) also reported that at 45 days sesbania aculeata and sesbania rostrata accumulated 185 and 219 kg n ha-1 respectively. rahman et al. (2013) stated that total n status of soil ranged from 0.075 to 0.098% (initial level 0.078%) after three years of continuous dhaincha biomass incorporation. 0.85 0.9 0.95 1 1.05 1.1 t0 t1 t2 t3 t4 t5 t6 t7 t8 1.01 1.02 1.08 1.01 1 0.95 1.01 0.94 1 so il o rg an ic m at te r (% ) treatments before gm after gm influence of green manuring crops 43 fig. 3. effect of different green manuring crops on soil total nitrogen. here, t1=s. aculeata, t2=s. rostrata,t3= c. juncea,t4=v. radiata,t5=v. mungo,t6=v. unguiculata, t7=l. leucocephala,t8=m. pudica other nutrients (k and p) among other nutrients k showed slightly increasing trends (0.22meq/100g) from initial soil (0.18meq/100g) after incorporation of green manures. the highest k content (0.22meq/100g) was found from t1 (s. aculeata) and t2 (s. rostrata) followed by t3 (0.21meq /100g) and t4 (0.20 meq/100g) that was superior to initial soils (table 1). increased k availability after green manuring has been reported by kute and mann (1969), and debnath and hajra (1972). in case of p in soil, a declined trend was found compared to initial soil (15.83 ppm). losses of phosphorous are normally thought to be mainly by surface run off and erosion but sometimes it can be lost through leaching also. georgantas and grigoropoulou (2006) opined that, in ph values less than 6 create a chemical bond between aluminum (al) and phosphate; whereas in higher values of soil ph (6-8), adsorption of phosphate ions occur on solid al or fe hydroxide. the p valued decrease may be due to the low ph and p fixation in soil. table 1. changes of soil fertility status of p and k for the incorporation of different green manuring crops treatments p (ppm) level k (meq 100g-1) level initial soil after gm incorporation initial soil after gm incorporation t0 15.83 15.83 0.18 0.18 t1 12.22 0.22 t2 15.00 0.22 t3 14.90 0.21 t4 11.45 0.20 t5 12.09 0.18 t6 11.86 0.18 t7 12.01 0.19 t8 13.54 0.20 here, t1=s. aculeata, t2=s. rostrata,t3= c. juncea,t4=v. radiata,t5=v. mungo, t6=v. unguiculata,t=l.leucocephala,t8=m. pudica conclusion 0 0.02 0.04 0.06 0.08 0.1 t0 t1 t2 t3 t4 t5 t6 t7 t8 0.04 0.05 0.084 0.051 0.04 0.03 0.08 0.052 0.051 a va ila b le s o il n it ro ge n (% ) treatments before gm after gm 44 irin et al. four green manuring cropsviz. s. rostrata, s. aculeata, c. juncea and v. unguiculata were found effective for green manuring in terms of their dry matter production, organic matter, nitrogen and potassium contribution. these green manures could be beneficial for nutrient exhaustive different cropping pattern through nitrogen as well as nk fertilizer saving and increase the soil fertility. acknowledgement the financial support of the authority of syed momena montaj foundation for their financial support during research work is gratefully acknowledged. references becker, m., m. ali, j.k. ladha and j.c.g. ottow. 1995. agronomic and economic evaluation of sesbania rostrata green manure establishment in irrigated rice. field crops res. 40(3): 135-141. biswas, t.d. and s.k. mukherjee. 1991. textbook of soil science. tata mcgraw–hill publishing company limited, new delhi. biswas, p.k., m. akhteruzzaman, a. quasem, and a.k.m.r. amin. 1996. effect of decomposition period of sesbania aculeata and nitrogen doses on rice yield and soil fertility. progress. agric.7(1): 107-109. debnath, n.c. and v. hajra. 1972. transformation of organic matter in soil in relation to mineralization of carbon and nutrient availability. india soc. soil sci. 20(2): 95-102. georgantas, d.a. and h.p. grigoropoulou. 2006. phosphorus and organic matter removal form synthetic waste water using alum and aluminum hydroxide. global nest j. 8(2): 121-130. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. 2nd ed. intl. rice res. inst., manila, philippines. pp.139-207. jenkinson, d.s., r.h. fox and j.h. rayner. 1985. interaction between fertilizer nitrogen and soil nitrogen the so-called “priming” effect. j. soil sci. 36: 425-444. kute, s.b. and h.s. mann. 1969. effect of green manuring on the composition of soil and wheat crop and the balance of major plant nutrients in the soil after crop. indian j. agric. sci. 39(1): 10-17. khind, c.s., m.s. maskina and o.p. meelu. 1987. effect of green manuring on rice. j. indian. soc. soil sci. 35: 135-145. mann, r.a., m.s. zia and m. saleem. 2000. an improved green manuring technology for sustaining the wheat rice system. quarterly sci. vision. 6(2): 53. mondal, u.k., g. singh, u.s. victor and k.l. sharma. 2003. green manuring: its effect on soil properties and crop growth under rice-wheat cropping system. european. j. agron.19(2): 225-237. odhiambo, j.j.o., j.b.o. ogola and t. madzivhandila. 2010. effect of green manure-maize rotation on maize grain yield and weed infestation levels. afr. j. agric. res. 5(8): 618–625. influence of green manuring crops 45 onim, j.f.m. 1986. multiple use of pegionpea. in: proceeding of icrisat consultative group meeting for eastern and central african regional research on grain legumes held at ilca, addis ababa, ethiopia, 8-10 december: 115-120. palaniappan, s.p. 1990. in: proc. international symposium on national resources management for sustainable agriculture, 6-10 february, 1990, new delhi. p.220. pimentel, d. and a. wilson. 2004. world population, agriculture and malnutrition. world watch 22-25 september/october. rahman, m.h., m.r. islam, m. jahiruddin, m.y. rafii, m.m. hanafi and m.a. malek. 2013. integrated nutrient management in maize-legume-rice cropping pattern and its impact on soil fertility. j. food agric. environ.11(1): 648-652. rinaudo, g., b. dreyfus and y. dommergues. 1983. sesbania rostrata green manure and the nitrogen content of rice crop and soil. soil biol. biochem. 15(1): 111-113. sanjoy, k., s. chand and b.p.s. gautam. 2015. enhance the soil health, nutrient uptake and yield of crops under rice-wheat cropping systems through green manuring. intl. j. trop. agric. 33(3): 2025-2028. sarwar, a.k.m.g., s.m.z. hossain and s.c. chanda. 2017. effect of dhaincha accessions on soil health and grain yield of rice. j. bio. agric. res.13(1&2): 1140-1145. singh, n.t. 1981. green manure as source of nutrients in rice production. organic matter and rice. irri.los banos philippine, pp.217-288. singh, a. and y.s. shivay. 2014. enhancement of growth parameters and productivity of basmati rice through summer green manuring and zinc fertilization. intl. j. bio-res. stress mng. 5(4): 486-494. zaman, s.k., n.i. bhuiyan and m.a. samad. 1995. age of green manure crops: an important aspect of biomass production and nitrogen accumulation. bangladesh j. agric. sci. 22: 107-112. microsoft word 13. baj-302_revised bangladesh agron. j. 2017, 21(1): 117-123 effect of crop establishment method and nutrient management on yield and yield attributes of short duration t. aman rice l. nahar*, a. b. s. sarker, m. m. mahbub and r. akter bangladesh rice research institute, joydebpur, gazipur-1701 *corresponding author, e-mail: lutfun.sau@gmail.com (received: 13 january 2018, accepted: 1 february 2018) keywords: crop establishment, nutrient management, yield and yield attributes abstract a field trial was conducted at agronomy farm of bangladesh rice research institute to find out the effect of crop establishment method and nutrient management on yield performance of brri developed short-duration aman rice var. brri dhan62 during july to october 2016. the trial comprised of four crop establishment methods viz., m1 = brri recommended puddle transplanting, m2 = system of rice intensification (sri) method (9-days old seedling transplantation), m3 = sprouted seed in line sowing and m4 = sprouted seed in broadcasting and three nutrient management levels viz.,n1 = brri recommended nutrient management, n2 = soil test-based nutrient management, n3 = control. the study was conducted in a factorial randomized complete block design with three replications. the result showed that planting methods had significant effects on the yield of rice. the sri method along with brri recommended fertilizer dose produced the maximum grain yield of 4.49 t ha-1 which was statistically similar with that produced in sri method dayand soil test-based nutrient management combination. the highest gross margin (tk. 36,308.00 ha-1) and cost benefit ratio (2.06) were observed in direct seeding of sprouted seed in line sowing method along with brri recommended fertilizer dose. so, direct seeding of sprouted seed in line could be a suitable planting method due to reduction of 26.0% production cost associated with seedling raising and transplanting operations. introduction rice (oryza sativa l.) is a staple food of more than half of the world’s population. in bangladesh, rice covers 77% of the total cropped area (quayum et al., 2012) and two third of the value added of the crop production. for rice cultivation different ways are followed in different rice growing agro-ecological zones of bangladesh. among them, mainly manual transplanting of seedlings into puddle soil is practiced in bangladesh which means a process of cultivating soil in standing water, consumes a large quantity of labor. chauhan et al., (2012) stated that sustainability of puddle transplanted rice (ptr) is threatened by increasing costs of production (especially labor) and due to increasing of agricultural labor scarcity which also delays crop establishment beyond the optimum time. transplanting is a resource and cost intensive method since the preparation of seedbed, the raising of seedling and the transplanting are labor and time intensive operations. high labor involvement for these operations consists of nearly one third of the total cost of production in bangladesh. to solve the high cost involvement technology, alternate methods of rice stand establishment are inevitable. direct seeding of sprouted seed in wet soil would be another option to mitigate huge amount of human labor and time consumption. direct seeding is more attractive than transplanting because it is cheaper and can result in an earlier harvest was stated by balasubramanian and hill, 2002. direct seeded rice seedling does not subjected to stress like being pulled from the soil of the nursery and do not need to reproduce fine rootlets. stoop et al. (2002) reported that young seedlings below 10 days of age are transplanted in sri, which produce higher number of tillers 118 nahar et al. than normal rice production systems, which contribute to higher grain yields (krishna et al., 2009). in most asian areas, the seedling age when transplanting to main field is about 25 to 30 days (irri, 1978). 15 and 40-day old seedlings had lower capability of stem elongation and tillering ability than 10-days old seedlings was observed by kim et al. (1999). fertilizer is one of the most important management factors to increase the productivity of crops (frg, 1997). farmers are using higher amount of fertilizer for every crop without considering crop requirement causing imbalance in the system. continuous degradation of soil health is caused due to imbalance use of chemical fertilizer and non-recycling of organic matter. from the above circumstances, it is noted that brri dhan62 was a short duration high yielding aman rice variety. so, the development of new rice variety may have a special adaptive capability under field conditions and can perform better under different nutrient management. for the above view, the performance of different seedling establishment methods and nutrient management practices on yield and yield attributes of aman rice was evaluated. materials and methods an experiment was conducted at the agronomy farm of bangladesh rice research institute, gazipur-1701 belongs to aez-28, during the period from july to october 2016 to find out the effect of different rice seedling establishment methods and nutrient management on the yield and yield attributes of short duration aman rice variety brri dhan62. details of the soil analysis have been sown in appendix i. soil of the experimental field belongs to the shallow red brown terrace soils. the experiential soil characters revealed that the soil was neutral having ph 6.64, organic matter content was (2.54%), total n (0.129%), p (18.12µg/g), and s (11.64µg/g) and k (0.10meq/100 g of soil). the soil nutrient content showed that organic matter was medium in level, n, s, k was low and whereas, p was optimum in level. the experiment comprised of four crop establishment methods viz. m1 = brri recommended puddle transplanting, m2 = sri method (9-days old seedling transplantation), m3 = sprouted seed sown in line and m4 = sprouted seed by broadcasting method and three nutrient management package viz. n1= brri recommended dose of fertilizer, n2=soil test based recommended dose of fertilizer, and n3 = control. on the basis of soil analysis data the exact fertilizer dose was calculated by using the following formula from frg’12. the formula was fr = ufci/cs x (st-ls) where, fr = fertilizer nutrient require for given soil test value uf = upper limit of the recommended fertilizer nutrient for the respective stvi class ci = unit of class intervals used for fertilizer nutrient recommendation cs = unit of class intervals used for stvi class st = soil test value ls= lower limit of the soil test value within stvi class the experiment was conducted in a factorial randomized complete block design (rcbd) with three replications. the sprouted seeds were sown in line (line to line distance 20 cm) and broadcasting methods in the assigned plots by manually on 29 july, 2016 and also sown in the nursery bed for raising seedling which was pre-pared previously. 25-day old seedlings were transplanted (2-3 seedlings hill-1) on 23 august 2016 with a spacing of 20 cm× 20 cm while in sri system 9-days old seedlings (1 seedling hill-1) were transplanted with a spacing 25cm x 25 cm on 08 august 2016. light irrigation was applied 45 days after seeding to facilitate germination and plant establishment depending upon soil moisture in dry seeded plots. the experiment was conducted in rainfed condition but supplemental irrigation was applied as per effect of crop establishment method and nutrient 119 necessary. according to brri recommended fertilizer was applied @ 200-62-83-56-5 kg ha-1 urea, triple super phosphate, muriate of potash, gypsum and zinc sulphate as per soil test based fertilizer was applied @ 113-32-116-46-5 kg ha-1 urea, triple super phosphate, muriate of potash, gypsum and zinc sulphate. entire quantity of all fertilizers except urea was applied as basal dose during final land preparation and mixed thoroughly with soil. urea was top -dressed in three equal installments i.e., during sowing/transplanting, tillering stage and seven days before panicle initiation. all agronomic practices were performed uniformly for all the treatments. two hand weedings were done at 30 and 50 dats. harvesting was done from 25 october 2016 to 01 november 2016 depending upon the maturity of the planting methods. data were analyzed statistically for analysis of variance (anova) following the method described by gomez and gomez (1984). results and discussion effect of crop establishment methods on yield and yield contributing characters crop establishment techniques differed significantly in their ability to produce all variables (table 1). brri recommended puddle transplanting (m1) produced the maximum plant (111.4 cm) that was statistically similar with sri (9-days old seedling transplantation) (m2) method. sprouted seed sown in line (m3) and broadcasting methods (m4) produced statistically similar (99.7 cm and 98.0 cm) plant and comparatively shorter plant than other two treatments. similarly, hassan et al. (2011) was found that transplanting rice produced the tallest plant (140.9 cm) while direct seeding broadcasting and line sowing method produced the shortest (128.1 cm) and (132.8 cm) plant. in sri system transplantation (m2) produced the maximum number (245.0) of effective tillers m-2 followed by m1 method (229.0). horie (2004) stated that practicing of transplanting one young seedling hill-1 with wider spacing (sri) had advantages in reducing transplanting injury and increasing tiller. hussain et al., (2004) also reported that sri methods produced the highest number of effective tiller than farmers practice. sprouted seed in line and broadcast sown methods produced the lowest number (217.0 and 199.0) of effective tillers m-2. transplanting of sri method (m2) produced maximum number of filled grains panicle-1 (99.0) followed by m1. the lowest number of filled grains panicle-1 (75.0) was recorded from m4. hussain et al. (2004) observed higher number of grains panicle-1 under sri compared to the farmers practice. the highest number of unfilled grains per panicle (27.0) was found in sprouted seed broadcasting methods followed by sprouted seed sown in line method. brri recommended (tpr) and sri method (transplanting of 9 days old seedling) produced the lowest and statistically similar number of unfilled gain panicle. the highest thousand grain weight (22.3 g) was obtained from sri method (9.0 days old seedlings) followed by brri recommended transplanting puddle rice and sprouted seed in line and broadcasting sowing method (table 1). the transplantation of sri method (9-days old seedling) produced higher grain yield (3.85 t ha-1) followed by brri recommended puddle transplanting. while sprouted seed in line and broadcasting methods produced the 3.56 and 2.98 t ha-1 grain yield, respectively. the increased straw yield (5.34 ha-1) was obtained from sri method (9days old seedling) transplantation method than the puddle transplanting system. however, husain et al. (2003) found 39% higher straw yield in sri compared to traditional methods while lowest straw yield (4.60 t ha-1) was obtained from sprouted seed broadcasting method. table 1. effect of different crop establishment methods on yield and yield attributes of short duration aman rice var. brri dhan62 crop establishment methods plant height (cm) effective tiller (m2) (no.) filled grain panicle-1 (no.) unfilled grain panicle-1 (no.) 1000grain weight. (g) grain yield ( t ha-1) straw yield (t ha-1) 120 nahar et al. m1 111.4a 229.0b 96.0 b 20.0 c 21.9 b 3.81ab 5.20 a m2 110.8a 245.0a 99.0 a 20.0 c 22.3 a 3.85a 5.34 a m3 99.7b 217.0c 86.0 c 24.0 b 21.9bc 3.56b 4.82 b m4 98.0b 199.0d 75.0 d 27.0 a 21.5c 2.98c 4.60 c cv (%) 4.59 6.64 3.34 9.34 1.69 5.16 3.74 f-test ** ** ** ** ** ** ** note: m1 = brri recommended transplanting puddle rice, m2 = sri method (9-days old seedling transplantation), m3 = sprouted seed in line sowing, m4 = sprouted seed in broadcasting effect of nutrient management the plant height was statistically identical between brri recommended fertilizer dose (n1) and soil test based nutrient management (n2) treatment, except control. number of effective tillers m-2 was highest (237.0) with brri recommended fertilizer dose (n1) that was at par with stb nutrient management (n2). similarly, amin et al. (2004) was found that increased fertilizer dose of npk increase number of total tillers plant-1. the control treatment produced the lowest (162.0) number of effective tiller. the maximum number (96.2) of filled grains panicle-1 was found with application of brri recommended fertilizer dose that was statistically similar with stb + (n2) treatment. the control treatment (n3) produced the lowest (73.1) number of filled grains panicle-1. consequently the control treatment produced the maximum number of unfilled grains panicle-1.. table 2. effect of different nutrient management practices on the yield and yield attributes of short duration aman rice variety brri dhan62 nutrient management plant height (cm) effective tiller (m2) (no.) filled grain panicle-1 (no.) unfilled grain panicle-1 (no.) 1000grain weight. (g) grain yield ( t ha-1) straw yield (t ha-1) n1 107.2a 245.0 a 100.3 a 17.9 c 22.02 a 4.05 a 5.20 a n2 107.2a 239.0 b 95.4 b 20.0 b 22.02 a 3.96 a 5.10 a n3 100.8b 184.0 c 73.1 c 30.0 a 21.6 b 2.63 b 4.70 b cv (%) 4.59 6.64 3.34 9.34 1.69 5.16 3.74 f-test ** ** ** ** * ** ** note: n1= brri recommended nutrient management, n2= soil test based nutrient management, n3= control brri recommended nutrient management (n1) and soil test based nutrient management produced the maximum 1000 grain weight (g), (22.02 g) followed by n2 while the control treatment gave the lowest 1000-grain weight (g). brri recommended nutrient management (n1) produced the maximum grain yield (4.05 t ha-1) that was statistically similar with stb nutrient management (3.96 t ha-1). the control treatment produced the lowest grain yield (2.63 t ha-1). straw yield (t ha-1) showed similar trends as in grain yield interaction effect of crop establishment method and nutrient management interaction effect of crop establishment methods and different nutrient management influenced significantly the studied parameters except plant height, number of unfilled grain panicle-1 and 1000-grain weight (table 3). sri method (m2) along with brri recommended fertilizer dose (n1) produced maximum number (280.0) of effective tillers (m-2) followed by combination of m2n2. sprouted seed in broadcasting method (m4) along with control fertilizer (n3) produced the lowest number (196.0) of effective tillers m-2. sri system (m2) along with brri recommended fertilizer dose (n1) produced maximum (111.0) number of filled grains panicle-1 effect of crop establishment method and nutrient 121 followed by treatment (m1) along with brri recommended fertilizer doses (n1) and soil test based fertilizer dose (n2). the maximum grain yield (4.49 t ha-1) was obtained from sri system (9-days old seedling) transplantation along with brri recommended fertilizer dose and stb fertilizer dose followed by brri recommended transplantation method. sprouted seed in broadcasting system along with control fertilizer dose gave the minimum (2.30 t ha-1) grain yield. the straw yield of rice followed similar trend as in grain yield. table 3. interaction effect of different crop establishment methods and nutrient management practices on the yield and yield attributes of short duration aman rice variety brri dhan62 interaction plant height (cm) effective tiller (m-2) (no.) filled grain panicle-1 (no.) unfilled grain panicle-1 (no.) 1000grain wt. (g) grain yield ( t ha-1) straw yield (t ha-1) m1× n1 113.4 265.0 b 106.0 b 14.6 21.9 4.30 ab 5.50 ab m1× n2 111.4 261.3 b 103..3 b 18.0 22.0 4.20 ab 5.40 b m1× n3 109.2 162.0 h 79.0 fg 26.6 21.9 2.93 cd 4.70 cd m2× n1 111.0 280.0 a 111.0 a 14.6 22.3 4.49 a 5.70 a m2× n2 113.1 276.0 a 109.0 a 16.3 22.9 4.49 a 5.60 ab m2× n3 105.6 180.0 g 77.0 g 28.6 21.7 2.56 de 4.73 cd m3× n1 102.0 230.0 c 98.3 c 17.6 21.9 4.03 ab 4.90 c m3× n2 101.6 222.0 d 89.0 d 23.3 21.7 3.93 b 4.83 cd m3× n3 95.4 198.0 f 72.3 h 31.3 21.9 2.73 de 4.73 cd m4× n1 102.6 205.0 e 86.0 e 24.6 21.9 3.40 c 4.60 cd m4× n2 98.4 197.0 f 80.3 f 22.3 21.5 3.23 c 4.63 cd m4× n3 93.1 196.0 f 64.3 i 33.3 21.2 2.30 e 4.56 d cv (%) 4.59 6.64 3.34 9.34 1.69 5.16 3.74 f-test ns ** ** ns ns ** ** note: m1 = brri recommended (tpr), m2 = sri method, m3 = sprouted seed in line sowing, m4 = sprouted seed in broadcasting; n1 = brri recommended nutrient management, n2 = soil test based nutrient management, n3 = control the maximum straw yield (5.70 t ha-1) of rice was recorded in sri system (9days old seedling) transplantation along with brri recommended fertilizer dose followed by soil test based fertilizer and brri recommended transplantation system along with brri recommended fertilizer dose. sprouted seed in broadcasting method along with control fertilizer produced the minimum straw yield (4.56 t ha-1). economic analysis variable cost varied due to the variation of labor number for crop establishment and for different fertilizer doses. the highest variable cost was incurred by the sri methods (9.0 days old seedling transplantation) along with brri recommended fertilizer doses (tk.44,582.00 ha−1) while the lowest variable cost was incurred by the sprouted direct seeding in broadcasting method with control fertilizer (tk. 26725.00 ha-1). this was similar to the results of kabir et al. (2009) who found lowest variable cost in direct seeded rice due to the omission of seedling raising, uprooting and transplanting. similar and highest net return (tk. 78575.00 ha-1) was obtained from m2n1 and m2n2 combinations but maximum gross margin tk. 36308.00 ha-1 and tk. 35227.00 ha-1 and benefit cost ratio and 2.06 and 2.05 was obtained from m3×n1 and m3×n2 combinations, respectively due to direct seeded rice is both costand labor-saving, although grain yield in direct seeded rice is comparatively less than that of transplanted rice. 122 nahar et al. table 4. economic performances of crop establishment methods and fertilizer management on yield of short duration aman rice variety interaction grain yield (t ha-1) total cost (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) bcr m1× n1 4.30 41167 75250 34083 1.83 m1× n2 4.20 40498 73500 33002 1.81 m1× n3 2.93 36450 51275 14825 1.41 m2× n1 4.49 44582 78575 33993 1.76 m2× n2 4.49 43913 78575 34662 1.79 m2× n3 2.56 39865 44800 4935 1.12 m3× n1 4.03 34217 70525 36308 2.06 m3× n2 3.93 33548 68775 35227 2.05 m3× n3 2.73 29500 47775 18275 1.62 m4× n1 3.40 31442 59500 28058 1.89 m4× n2 3.23 30773 56525 25752 1.84 m4× n3 2.30 26725 40250 13525 1.51 grain price: tk. 16.75 kg-1 conclusion from the results of the study, it can be concluded that short-duration aman variety brri dhan62 performed better under sri and brri recommended transplantation method along with brri recommended fertilizer doses than other methods in terms of grain yield. from the economic point of view, the cultivation of brri dhan62 with direct seeding of spouted seed in line can be recommended for reducing the production cost. references amin, m., m. a. khan, e. a. khan and m. ramzan. 2004. effect of increased plant density and fertilizer dose on the yield of rice variety ir-6. j. res. sci. 15(1): 9-16 balasubramanian, v, j. e. hill. 2002. direct seeding of rice in asia: emerging issues and strategic research needs for the 21st century. in: pandey s, mortimer m, wade l, tuong tp, lopez k, hardy b, eds. direct seeding: research strategies and opportunities. los ban˜os, the philippines: international rice research institute, pp. 15–39. chauhan, b. s., g. mahajan, v. sardana, j. timsina and m. l. jat. 2012. productivity and sustainability of the rice-wheat cropping system in the indo-gangetic plains of the indian subcontinent: problems opportunities, and strategies. adv. agron. 117: 315–369. frg. 1997. fertilizer recommendation guide, bangladesh agricultural research council, farmgate, dhaka. p.185. gomez, a. a. and a. a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons. new york. pp. 207-215. hassan, a. and k. behzad. 2011. assessment of direct seeded and transplanting methods of rice cultivars in the northern part of iran. african j. agril. res. 6 (31): 6492-6498 effect of crop establishment method and nutrient 123 husain, a. m. m., p. barua, and s. r. halder. 2003. verification and refinement of the system of rice intensification (sri) project in selected areas of bangladesh. trial monitoring survey report on chatkhil and begumgonj in noakhali district. brac. hussain, a. m. m., g. chpwhan, a. b. m. z. rahman, r. uddin and p. barua. 2004. report on the system of rice intensification. petrra technology workshop, brri auditorium, gazipur. irri. 1978. international rice research institute annual report. international rice research institute. los banos, philippines. kabir, m. h., m. s. u. bhuiya, a. saha, m. a. h. khan and n. e. elahi. 2009. effect of crop establishment method and time of nitrogen application on the productivity of boro rice in lowland ecosystem. bangladesh rice journal, 14(1-2) pp. 1-6. kim, s. s., b. k. kim, m. g. choi, n. h. back, w. y. choi and s. y. lee. 1999. effect of seedling age on growth and yield on machine transplanted rice in southern plain region. korean j. crop sci. 44(2): 122-128. krishna, a. and n. k. biradarpatil. 2009. influence of seedling age and spacing on seed yield and quality of short duration rice under system of rice intensification cultivation. karnataka j. agric. sci. 22(1): 53-55 quayum, m. a., a. m. ali, m. a. salam. 2012. impact of power tillers on profitability of some cropping patterns in some selected areas of bangladesh. bangladesh. j. agric.res. 37: 415432. microsoft word 11. baj-300_revised bangladesh agron. j. 2018, 21(1): 95-103 effect of seed rate and walkway on yield of field pea under relay cropping with t. aman rice m. o. ali1*, a.h.m.m.r. talukder2 and l. nahar3 1principal scientific officer, pulses research sub-station, bari, joydebpur, gazipur-1701 2scientific officer, plant physiology division, bari, joydebpur, gazipur-1701 3scientific officer, agronomy division, brri, joydebpur, gazipur-1701 *corresponding author, e-mail: omaraliprc@gmail.com (received: 30 december 2017, accepted: 30 january 2018) keywords: seed rate, walking way, relay cropping and field pea abstract the field experiment was conducted at pulses research centre (prc), ishurdi, pabna and regional agricultural research station (rars), jamalpur during rabi 2012-2013 to find out the effect of seed rate and walkway for green pea production as relay cropping with transplanted aman rice. the experiment was based on six seed rates @ 50, 60, 70, 80, 90 and 100 kg ha-1 and two walking ways viz. 15 cm wide walkway at 2 m interval over the plot and control with three replications. a local cultivar of pea, named natore was used in this trial. results revealed that the treatment with 100 kg seed ha-1 gave the highest pod yield of 5.13 t ha-1 and 4.98 t ha-1 at jamalpur and ishurdi locations, respectively which was similar to 80 (s4) and 90 (s5) kg seed ha-1.. walkway had no significant variation in yield and yield contributing characters but it produced the higher yield over the control. using walkway, 100 kg seed ha-1 (s6) and 15 cm walkway at 2 m interval over the plot (w1) produced the highest pod yield of 5.14 t ha-1 and 4.95 t ha-1 and fodder yield of 6.70 t ha-1 and 6.13 t ha-1 at jamalpur and ishurdi locations, respectively. maximum gross margin of tk. 1,06,040 ha-1 and tk. 1,02,401 ha-1 was contributed by combinations of using 100 kg seed ha-1 and 15 cm walking way but maximum benefit cost ratio (bcr) of 3.40 and 3.43 were obtained from s5×w1 combination at jamalpur and ishurdi locations, respectively. it is concluded that pea cultivar can be successfully cultivated for green pod production through the use of 90-100 kg ha-1 seed with walkway of 15 cm wide in the plot after 2 m intervals. introduction pea (pisum sativum), also known as the field or garden pea,is one of the most important and popular legume vegetable crops grown in many countries all over the world. according to fao (2010), pea is the fourth leading legume in terms of consumption in the world with a total production of 10.2 million tonnes. it is a good source of protein (21-25%) (bhat et al., 2013) and plays an important role in human nutrition since they are also rich in calories, vitamins and minerals. on the other hand, mckenzie and sponer (1999) opined that peas are widely grown for hay, pasturage or silage production either alone or mixed with cereals as relay and inter or mixed crop. under this situation, relay and inter or mixed cropping would be an improved cropping technology to sow various pulses crops in the standing rice crop field, just before the harvest to ensure germination using the residual moisture and to avoid tillage operations. earlier research conducted by ali et al., (2018) revealed that local cultivar of pea named natore would be extensively cultivated as relay crop with t. aman rice under residual soil moisture. seed yield of pea obtained by local farmers in relay cropping or conventional system is quite low and variable. to meet up the future demand of nutrient for growing populations can be 96 ali et al. achieved by increasing area under field pea or maximizing yield unit-1 area, by adopting appropriate production technology with use of optimum seed rate and proper management practices. plant population is a yield limiting factor in field pea production that mainly influenced by seed rate. if more seed rate is used, plant population will be more and there will be competition among plants for water, nutrients and sunlight resulting in low quality and low yield. if less seed rate is used yield will be less due to lesser number of plants unit area1 (attarde and khuspe, 1989). an earlier study was conducted by kibe and kamithi (2007) and dahmardeh et al. (2010) showed that seeding rate and cultivar are important factors affecting yield and quality of grain legumes. the competition ability of crops may be increased due to increasing seeding rate. as a result profitability of the crop may or may not increase owing to high seed cost in pulses. rajput et al. (1989) concluded that maximum grain yield was obtained with the increase in seed rate, while minimum grain yield was produced by low seed rate. consequently, as a relay cropping system field pea seed is broadcasted by the farmers into standing t. aman rice at 10-15 days prior to harvest of rice. but the farmers’ do not use optimum seed rate, sometimes use high or low which produced lower yield. besides this, pea cultivar named natore local is newly introduced in the research system which needs to find out the optimum seed rate for handsome yield as green pod and forage. conventionally, farmers do not keep any walkway in the plot to facilitate the pod picking. as a result during the harvesting of pod many immature or mature green pods may be destroyed by foot pressures that directly affect the final pod yield. therefore, the experiment was conducted to find out the optimum seed rate and walkway for easily harvest of green pod for vegetable and forage without damaging of plants and immature pod under relay cropping with t. aman rice to achieve higher yield. materials and methods the study was conducted at pulses research centre (prc), ishurdi, pabna, and regional agricultural research station (rars), jamalpur belongs to (aez-11) and (aez-9) respectively under bangladesh agricultural research institute (bari), during rabi 2012-2013 to select suitable management practices viz. seed rate and walking way for the convenient of pod picking on yield of field pea var. natore local as relay cropping with t. aman rice which was found promising for green pod production through earlier screening program. the geographic coordinates of the research studied areas were located between 24.15° north latitude and 89.0° east longitude and 24034’ and 25026’ north latitude and between 89040’ and 90012’ east longitude respectively. the six seed rates s1=50, s2 =60, s3 =70, s4 =80, s5 =90, s6 =100 kg ha-1 and two walking way viz. w1=15 cm walking way was maintained after 2 m interval in the plot and w2 =control were used as a treatment. considering the over location the unit plot size was maintained by 5m x× 4 m. the experiment was conducted under randomized complete block design with three replications for both the locations. seeds were soaked into water over a night to ensure the optimum germination prior to sowing. as per seed rate seeds were sown as relay cropping in the existing rice field before 15 days of rice harvest on 15 november, 2012 at ishurdi and 29 october, 2012 at jamalpur location. during seed sowing 15 cm walking way was maintained apart two meter in a plot. t. aman was harvested leaving 30 cm straw height from ground level. no weeding was done during the whole crop growing period. once a light irrigation (1 cm) was applied at 35 dae for better crop establishment at jamalpur location only. pods were harvested at different dated on the basis of pod maturity as a green pod. ten plants were selected randomly from each plot before harvest of crop to record data on yield attributes while pod yield was collected on the whole plot basis at different day’s interval when bearing pod was matured as a green pod. weight of fresh green pod obtained from the different harvests were recorded and summed up at the end of the crops life and converted into t ha-1. collected data were analyzed statistically following the anova technique with the help of mstat-c effect of seed rate and walkway on yield of field 97 software and mean separation was done as per lsd test according to gomez and gomez (1984). variable cost of cultivation, gross margin and bcr were calculated considering the wages of local labour and input (seed) prices and selling prices of seed at the harvesting time. economic analysis was done in terms of total cost of cultivation, net return and bcr. benefit cost ratio was calculated by using following formula: benefit cost ratio (bcr) results and discussion weather information the mean maximum temperature 33.8oc and 31.1oc was attained during the period october’2012 at jamalpur and ishurdi locations respectively while mean minimum temperature 9.6oc and 12.7oc was attained during january’ 2013 at jamalpur and ishurdi location respectively. 04mm and 02mm rainfall was prevailed at 1st fortnight of october’ 2012 and november’2012 respectively at jamalpur location. but 05mm rainfall was found at during 1st fortnight of january’2013 at ishwardi location. table 1. fortnightly maximum, minimum temperature (oc) and total rainfall (mm) at jamlpur and ishurdi location during rabi 2012-2013 during cropping season jamalpur location ishurdi location month fortnight temperature (oc) fortnight temperature (oc) rainfall (mm) max. min. rainfall (mm) max. min. rainfall (mm) oct’12 1st fortnight 33.8 23.8 04 1st fortnight 32.3 24.3 00 2nd fortnight 33.8 20.6 00 2nd fortnight 30.0 20.0 00 nov’12 1st fortnight 29.5 18.6 02 1st fortnight 29.8 17.0 00 2nd fortnight 28.9 15.2 00 2nd fortnight 29.6 18.2 00 dec’12 1st fortnight 25.6 13.9 00 1st fortnight 23.8 14.8 00 2nd fortnight 20.3 10.3 00 2nd fortnight 24.0 15.5 00 jan’13 1st fortnight 19.9 9.3 00 1st fortnight 23.0 12.7 05 2nd fortnight 24.1 9.9 00 2nd fortnight 23.5 12.8 00 feb’13 1st fortnight 26.8 13.8 00 1st fortnight 28.0 15.3 00 2nd fortnight 27.6 15.8 02 2nd fortnight 27.5 15.2 00 effect of seed rate the results of seed rates are presented in table 2. days require attaining 50% flowering of field pea variety of natore local did not show significant variation among the different seed rates for both the locations. considering the both locations it ranged from 45 to 47 days. statistical analysis of the data revealed that seed rate had a significant (p ≤< 0.01) effect on number of plant at per square meter at emergence. the number of plants m-2 was gradually increased with increasing seed rate and significantly maximum number (101 & 98) of plants m-2 was obtained from the 100 kg seed ha-1 (s6) at jamalpur and ishurdi locations, respectively. the minimum number (50 & 47) of plants at m-2 was found in 50 kg seed ha-1 (s1) treatment for both locations. actually the number of plants m-2 was mainly influenced due to the variation of different seed rates. similarly, mujahid (1972), reported that plant density increases plants unit area-1 as the seed rate increases. shahzad et al., (2007) stated that height of the crop is mainly controlled by the genetic make up of a genotype and it can also be affected by the environmental factors. but plant height differed significantly among the different seed rate considering both the locations. under this study plant 98 ali et al. height was increased linearly increasing plant population might be due to competition of plants in higher densities on light and space, resulting in taller plants. considering the both locations the tallest plant (116.0 cm) and (108 cm) was noted in those plots where maximum seed rate (100 kg ha-1) was sown that was statistically similar with seed rate of 90 kg ha-1while shortest plants (101cm) and (99.0 cm) was recorded for those plots where lower seed rate (50 kg ha-1) was sown for jamalpur and ishurdi locations respectively. similarly, this finding was supported by inanç and yıldırım (2007), who indicated that denser plant population of pea increased plant height due to competition among plants. number of branches plant-1 differed significantly among the different seed rate in ishurdi location while in jamalpur location it showed non significant variation. significantly maximum number of branches plant-1 was obtained from 50 kg seed ha-1 (s1) at ishurdi location other treatments gave the statistically similar and minimum number of branches plant-1 which might be due less population which got more light and space. pandey and gritton (1975) stated that number of pods per plant is one of the most important components in determining the yield of several legume crops including pea. meadley and milbourn (1970) have well documented the response of pods per plant at differing densities of plant. anderson and white (1974) reported that pod numbers per plant and peas per pod decreased with increasing density. number of pod plant-1 differed significantly among different seed rate under the present studies and considering the both locations maximum number (8.64 & 8.06) of pods plant-1 was obtained from the 50 kg seed ha-1 (s1) it might be due to the less intra plant competition that was statistically similar to the 60 kg and 70 kg seed ha-1 at jamalpur and ishurdi locations while the minimum number of pod plant-1 was obtained from the 100 kg seed ha-1. according to present research at two locations, increasing seeding rates decreased number of seeds per pod. cousin (1997) stated that number of seeds per pod depends partially on the cultivar and on the environmental conditions but has also been documented to be affected by plant density. the highest number (6.12 & 5.84) of seeds /pod was obtained by 50 kg ha-1 seed rate at jamalpur and ishurdi locations, respectively that was statistically similar with 60 kg and 70 kg seed ha-1 but the lowest number of seed / pod (5.04 and 4.68) was in 100 kg ha-1 seed rate at jamalpur and ishurdi, respectively. significant variation was observed on pod and fodder yield (t ha-1) among the different seed rate for both the locations. the maximum pod yield (5.13 & 4.98 t ha-1) was found from 100 kg seed ha-1 (s6) seed rate which was statistically similar with 80 kg seed ha-1 (s4) and 90 kg seed ha-1 (s5) at jamalpur location whereas at ishurdi maximum pod yield (4.98 t ha-1) was found in 100 kg seed ha-1 which was statistically similar to 90 kg seed ha-1. it might be due optimum plant population with cumulative influence of yield contributing characters. pod yield (t ha-1) was gradually increased with the increasing of seed rate. similarly, gan et al., (2003) reported that the seed yield of dry pea increased with increasing plant population densities from 30 to 80 plant m-2. fodder yields increased linearly with increasing seeding rates. significantly, 100 kg seed ha-1 (s6) produced maximum fodder yield (6.68 & 6.22 t ha-1) at jamalpur and ishurdi location, respectively. it might be due to maximum plant stand which enhanced fodder production. minimum fodder yield (3.50 t ha-1 and 2.47 t ha-1 was obtained from 50 kg seed ha-1 (s1) at jamalpur and ishurdi locations, respectively. table 2. effect of different seed rate on phenological, yield and yield attributes of pea as relay cropped with t.aman rice at jamalpur and ishurdi location during rabi 2012-2013 seed rate (kg ha-1) days to flowering (days) number of plants m-2 at emergence plant height (cm) branch plant-1 (no.) effect of seed rate and walkway on yield of field 99 jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi s1 46.0 46.0 50.0 e 47.0f 101.0 d 99.0 b 1.11 1.34 a s2 46.0 46.0 61.0 d 57.0e 103.0 cd 99.0 b 1.18 1.17 b s3 47.0 47.0 71.0 c 68.0d 103.0 cd 100.0 b 1.16 1.16 b s4 45.0 45.0 81.0 bc 78.0c 108.0 bc 100.0 b 1.09 1.19 b s5 46.0 46.0 94.0 b 88.0 b 112.0 b 105.0 ab 1.12 1.17 b s6 47.0 47.0 101.0 a 98.0a 116.0 a 108.0 a 1.12 1.16 b lsd (0.05) ns ns 3.21 3.21 5.68 5.66 ns 0.07 cv (%) 2.04 1.59 3.21 3.71 4.44 4.63 7.76 5.36 note: ns= non significance, *=5% level of significance, **=1% level of significance; s1= 50 kg seed ha-1, s2= 60 kg seed ha-1, s3= 70 kg seed ha-1, s4= 80 kg ha-1, s5= 90 kg ha-1, s6=100 kg ha-1 table 2. (contd.) seed rate (kg ha-1) number of pod plant-1 number of seed pod-1 green pod yield (t ha-1) fodder yield (t ha-1) jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi s1 8.64 a 8.06 a 6.12 a 5.84a 2.62 c 2.43 d 3.50e 2.47 e s2 8.58a 7.70 a 5.61 ab 5.45a 3.13 c 3.07 c 4.12d 3.84 d s3 8.20a 7.54 ab 5.17 bc 5.30ab 3.90 b 3.26 c 4.78c 4.67 c s4 7.05b 7.30 b 5.50 bc 4.60c 4.70 a 4.38 b 5.35b 5.19 bc s5 6.50b 6.73 b 5.06 c 4.83bc 5.05 a 4.90 a 5.83b 5.49 b s6 6.42b 6.53 b 5.04 c 4.68c 5.13 a 4.98 a 6.68a 6.22 a lsd (0.05) 0.78 0.78 0.54 0.569 0.58 0.39 0.57 0.57 cv (%) 8.62 8.92 8.40 9.28 11.82 8.54 9.49 10.29 note: s1= 50 kg seed ha-1, s2= 60 kg seed ha-1, s3= 70 kg seed ha-1, s4= 80 kg ha-1, s5= 90 kg ha-1, s6=100 kg ha-1 according to result of two locations, an increase in seeding rate from 50 to 100 kg seeds ha-1 produced an approximately 91% and 152.0% increase in fodder yield. these results were consistent with the findings of townley -smith and wright (1994). effect of walkway way on yield and yield contributing characters the results presented in the table 3 revealed that none of the variables showed significant variation between the walking ways for both the locations. but numerically, the higher pod and fodder yield of 4.16 t ha-1& 5.05 t ha-1for jamalpur, and 3.88 t ha-1& 4.65 t ha-1 for ishurdi locations were obtained from the walking way, 15 cm after 2m interval in the plot and the lower pod and fodder yield was in control. it might be due to the less affect on plant by foot pressure during pod harvesting. table 3. effect of walkway facilities on phenological, yield and yield attributes pea with t.aman rice at jamalpur and ishurdi location during rabi 2012-2013 path facilities days to flowering (days) number of plants m-2 at emergence plant height (cm) branch plant-1 (no.) jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi w1 46.0 46.0 76.0 71.5 106.0 102.3 1.16 1.204 w2 46.0 46.0 76.0 73.2 108.0 101.6 1.11 1.191 lsd0.05 ns ns ns ns ns ns ns ns cv (%) 2.04 1.59 3.52 3.71 4.44 4.63 7.76 5.36 100 ali et al. ns= non significance, w1= 15 cm wide walkway way at 2 m interval over the plot and w2= control table 3 contd. path facilities number of pods plant-1 number of seeds pod-1 pod yield (t ha-1) fodder yield ( t ha-1) jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi w1 7.55 7.15 5.32 5.13 4.16 3.88 5.05 4.65 w2 7.56 7.48 5.51 5.10 4.01 3.79 5.01 4.64 lsd0.05 ns ns ns ns ns ns ns ns cv (%) 8.62 8.92 8.40 9.28 11.82 8.54 9.49 10.29 ns= non significance, w1= 15 cm walking way at 2 m interval over the plot and, w2= control interaction effect of seed rate and walkway the results showed that none of variables did not differ significantly due to the interaction effect of seed rate and walking way for both the locations. anyway, numerically the highest pod yield of 5.14 and 4.95 t ha-1 was produced by s6×w1 combination at jamalpur and ishurdi, respectively. similar treatment also produced the highest fodder yield 6.70 and 6.13 t ha-1 at jamalpur and ishurdi, respectively. economic performance considering th locations, maximum cost of cultivation was tk. 45,000 ha-1 and tk. 43,500 ha-1 for s6×w1 combination and the combination of s1×w2 needed minimum cost of cultivation was tk. 40,000 ha-1 and tk. 38,000 ha-1 at jamalpur and ishurdi location, respectively (table 4). cost of cultivation was mainly varied among the combinations which might be due to the variation of seed rate. the maximum gross return tk. 1, 51,040 was found from s6×w1 combination at jamalpur while at ishurdi tk.1, 45,910 ha-1 was found from same combination. maximum gross margin of tk. 1, 06,040 ha-1 and tk. 1,02,550 ha-1 were obtained from the treatment combination of s6×w1 at jamalpur, and ishurdi locations, respectively. at jamalpur and ishurdi location maximum benefit cost ratio (bcr) 3.40 and 3.43 was obtained from s5×w1 combination which was very similar to s5×w2, s6×w1 and s6×w2 combinations (table 4 contd.). table 4. economic performances of seed rate and walkway way on yield of peas as relay cropped with t. aman rice at jamalpur and ishurdi location during rabi 2012-2013 varieties pod yield (t ha-1) fodder yield ( t ha-1) cost of cultivation (tk. ha-1) jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi s1×w1 2.90 2.65 3.50 2.50 40,000 38500 s1×w2 2.34 2.20 3.43 2.43 40,000 38000 s2×w1 3.11 3.04 4.13 3.77 41,200 39400 s2×w2 3.15 3.09 4.12 3.91 41,200 39000 s3×w1 3.95 3.32 4.90 4.73 42,000 40500 s3×w2 3.85 3.20 4.65 4.60 42,000 40100 s4×w1 4.65 4.42 5.30 5.18 43,000 41,300 s4×w2 4.75 4.35 5.40 5.20 43,000 40,900 s5×w1 5.10 4.92 5.80 5.59 43,800 42,000 s5×w2 4.99 4.89 5.85 5.40 43,800 41,700 s6×w1 5.14 4.95 6.70 6.13 45,000 43,500 s6×w2 5.11 4.91 6.65 5.95 45,000 43,000 table 4 (contd) effect of seed rate and walkway on yield of field 101 varieties gross return (pod + fodder) (tk. ha-1) gross margin (tk. ha-1) bcr jamalpur ishurdi jamalpur ishurdi jamalpur ishurdi s1×w1 83,300 76,550 43,300 38,050 2.08 1.99 s1×w2 68,040 64,260 28,040 26,260 1.70 1.69 s2×w1 91,510 89,620 50,310 50,220 2.22 2.27 s2×w2 92,870 91,250 51,670 52,250 2.25 2.34 s3×w1 1,16,110 99,100 74,110 58,600 2.76 2.45 s3×w2 1,13,150 95,600 71,150 55,500 2.69 2.38 s4×w1 1,35,910 1,29,700 92,910 88,400 3.16 3.14 s4×w2 1,38,650 1,27,850 95,650 86,950 3.22 3.13 s5×w1 1,48,880 ,144,020 1,05,080 1,02,020 3.40 3.43 s5×w2 1,45,530 1,42,830 1,01,730 1,01,130 3.32 3.43 s6×w1 1,51,040 1,45,910 1,06,040 1,02,410 3.36 3.35 s6×w2 1,49,870 1,44,470 1,04,870 1,01,470 3.33 3.36 price motorshuti pod :tk. 27 kg-1 (mean values of two locations) ; fodder tk. 2 kg-1, (mean values of two locations), pod harvesting @ tk. 8 kg-1 (mean value of two locations) conclusion the aforesaid results of two locations indicated that seed rate had significant effect on yield in field pea. the highest pod yield of 5.13 t ha-1 and 4.98 t ha-1 was obtained from using 100 kg seed ha-1 at jamalpur and ishurdi, respectively which showed statistically similar results obtained from using 80 and 90 kg seed ha-1 at jamalpur 90 kg ha-1 at ishurdi. in conclusion, 90100 kg seed ha-1 can be recommended for extensive cultivation of field pea as a relay crop with t. aman rice. though walkway facilities did not show any significant variation in pod yield but walk way it can be recommended for easy and smart-picking of green pod without damaging the crop. references ali, m.o., a. sarker, a. h. m. m. r.talukder, m. s.alam,m. a. islam and j. hossain. 2018. adaptation of pea (pisum sativum l) as relay crop with monsoon rice is a resource conservation technology in medium high to medium low lands of bangladesh. global adv. res. j. agric. sci. 7(1):011-019. anderson, j. a. d. and j. g. h. white. 1974. yield of green peas. ii. effects of water and plant density. new zealand j. exp. agric. 2: 165-171. attarde, d. r. and v. s. khuspe. 1989. response of wheat varieties to different levels of seed rate and nitrogen. j. maharashtra agric. univ. 4: 309-310. bhat, t.a. m.,m. gupta, m. a. ganai, r. a. ahanger and h. a. bhat. 2013. yield, soil health and nutrient utilization of field pea (pisum sativum l.) as affected by phosphorus and biofertilizers under subtropical conditions of jammu. int. j. modern plant animal sci. 1(1):1-8. cousin, r. 1997. peas (pisum sativum l.). field crops res. 53: 111-130. dahmardeh, m., m. ramroodi and j. valizadeh. 2010. effect of plant density and cultivars on growth, yield and yield components of faba bean (vicia faba l.). afr j. of biot. 9(50): 8643-8647. 102 ali et al. fao (food and agricultural organization of the united nations) 2010. http://faostat.fao.org/site/339/default.aspx gan, y. t., p. r. miller, b. g. mcconkey, r. p. zentner, p. h. liu and c. l. mcdonald. 2003. optimum plant population density for chickpea and dry pea in a semiarid environment. can. j. plant sci. 83: 1-9. gomez, a. a. and a. a gomez. 1984. statistical procedures of agricultural research. john wiley and sons, new york, 20-21. inanç, s and b. yıldırım. 2007. the effect of different row space applications on the yield and yield components in pea (pisum sativum l.). turkish vii. field crops cong. 25-27 july, erzurum. kibe, a. m. and d. k. kamithi. 2007. production potential of desi chickpea grown under various nitrogen and planting densities at naivasha. agril. j. 2(4): 520-525. mckenzie, d. b. and d. sponer. 1999. white lupin: an alternative to pea in oat-legume forage mixtures grown in new found land. can. j. plant sci. 79: 43–47. meadley, j. t. and g. m. milbourn. 1970. the growth of vining peas. ii. the effect of density of planting. journal of agril. sci. cambridge. 74: 273-278. mujahid, z. h. 1972. effect of row spacing and seed rate on the growth and yield of wheat variety chenab-70. m.sc. thesis, university of agriculture, faisalabad, pakistan. pandley, s. and e. t. gritton. 1975. genotypic and phenotypic variances and correlations in peas. can. j. plant sci. 3: 353-356. rajput, f. k., m. m. j. rajput, s. m. aslam and a. w. baloch. 1989. the growth and yield of wheat as affected by different seed rates and raw spacing. sarhad j. agric. 5: 479-482. shahzad, m. a., w. u. din, s. t. sahi, m. m. khan, ehsanullah and m. ahmad. 2007. effect of sowing dates and seed treatment on grain yield and quality of wheat. pakistan j. agri. sci. 44 (4): 581-583. townley-smith, l. and a. t. wright. 1994. field pea cultivar and weed response to crop seed rate in western canada. can. j. plant sci. 74: 387-393. a simple assessment on spatial variability of soil chemical properties and rice yield in tidal submergence ecosystem bangladesh agron. j. 2015, 18(2): 79-87 assessment of soil chemical properties and rice yield in tidal submergence ecosystem m.a.a. mamun1*, m.m. haque1, q. a. khaliq1, m.a. karim1, a.j.m.s. karim1, a.j. mridha2 and m.a. saleque2 1bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 2bangladesh rice research institute, gazipur-1701, bangladesh *corresponding author: aamamunbrri@yahoo.com key words: nitrogen, potassium, phosphorus, rice, , organic matter abstract spatial variability of soil chemical properties is critical for improving rice productivity and sustainable farming techniques. however, a systematic assessment on the spatial variability of tidal ecosystem has not been conducted. so, 144 soil samples were collected across barisal, borguna and jalkhati districts and analyzed for six common chemical properties. rice yield data was obtained by surveying farmers during crop harvest. soil parameters and rice yield varied considerably throughout the study areas and their coefficients of variation ranged from 8.77 to 71.04%. slight variability was observed for soil organic matter (som) and available k. the ph of the soils was slightly acidic to alkaline. these paddy fields were characterized by high concentrations of som, available p, k and s; but low total n. rice yield was significantly and positively correlated with ph, available k and s, but negatively correlated with som. introduction low productive tidal submergence ecosystem is one of the major unfavorable agro-ecological zones in bangladesh (hossain et al., 2002) and covers about 2.0 m ha (elahi et al., 2001). the northern half of these tidal wetlands is non-saline. the major environmental problem for crop production is twice daily tidal water inundation of land (roy et al., 2003). tidal water depth could be 6-90 cm during april to november with the highest peak in august (debnath et al., 2013). soil chemical properties are typically related to variability in crop yield and their degradation will result in a decrease of soil fertility and nutrients (gray and morant, 2003). scientific information concerning spatial variability and distribution of soil properties is critical for farmers attempting to increase fertilizer use-efficiency and crop productivity. fertilization based on soil fertility may also lead to reduced fertilizer inputs without reducing yield (jalali, 2007). assessing the spatial variability of soil chemical properties is crucial to design sustainable cropping systems.moreover, the sedimentation associated with tidal flooding is an important source of nitrogen (n), phosphorus (p) and potassium (k) (saleque et al., 2010). in these sediments, n is deposited mostly as a component of organic matter (om), whereas p is associated primarily with the fine-grained clay minerals (odum, 1988). understanding field spatial variation and the relationships with crop response may substantially increase the input effectiveness and average crop yield (virgilio et al., 2007). yamagishi et al. (2003) found that crop yield was significantly correlated with soil properties. evaluating the spatial variability of rice yield and related chemical properties in low-yield paddy areas of tidal ecosystem is urgently needed for regional planning purposes. therefore, the objectives of the present study were to estimate the current status and regional spatial variability of soil chemical properties and analyze the relationships between rice yield and selected chemical properties. materials and methods locations 80 mamun et al. soil samples were collected from 144 farmers’ fields of barisal, borguna and jalkhati district (table 1). the area covers southern part of the country including and belongs to agro ecological zone-13, ganges tidal floodplain of bangladesh . this region occupies an extensive area of tidal floodplain land in the southern part of the country. the common cropping pattern is fallow-aus-aman. the samples were collected in july, 2013. table 1. number of soil samples collected across different locations in tidal areas districts upazilas villages symbol number of samples barisal gournadi pinglakhati pk 24 kutubpur kt 24 bakergonj niamoti nm 24 char boalia cb 24 borguna batagi bibichini bb 24 jalkhati nalchiti dopdopia dp 24 total 144 collection and analysis of soil samples the soil samples of 0-15 cm depth were collected from selected plots to determine the physicochemical properties. the soil samples were air-dried, crushed and passed through 2 mm sieve and stored in polyethylene bags at room temperature, prior to analyze organic carbon and total nitrogen content. soil organic carbon was analyzed by walkley-black wet oxidation method (allison, 1965). a portion of 1.0 g air-dried soil sample (passed through 0.5 mm sieve) was taken in a 500 ml erlenmeyer flask. ten ml 1n k2cr2o7 and 20 ml conc. h2so4 was added to the flask and allowed to react for 30 minutes after which 200 ml distilled water and 10 ml conc. h3po4 was added. one ml orthophenanthroline indicator was added to the flask and was titrated with about 0.5n feso4 solution. blank titration was run to calculate the strength of the feso4 solution. total nitrogen was determined following bremner (1965) method, but microkjeldahl instrument was used. a portion of 0.5 g air-dried soil sample was digested in 3 ml conc. h2so4 in the presence of 0.5 g of digestion mixture ( 50: 10: 1 k2so4 : cuso4.5h2o: metallic selenium). the digested sample was distillated with 40% naoh and the distillate was collected in 4% boric acid containing three drops of mixed indicator (bromocresol green and methyl red), which was then titrated with 0.05 n h2so4. c: n ratio was calculated by dividing the results of organic carbon by total nitrogen. all measurements of organic carbon and total nitrogen were done in triplicate. soil ph in water was measured from a soil: water ratio 1: 2.5 using glass electrode method (peech, 1965). twenty gram of air-dried 80 sieved soil sample was taken in a 100 ml of plastic bottle and 50 ml of distilled water was added. the suspension was stirred with a glass-rod at regular interval for 30 minutes. a glass electrode ph meter calibrated with buffer ph 7.0 and 4.0 and the ph of soil suspension was measured. the measurement was done in triplicate. olsen-p was extracted with 0.5m sodium bicarbonate (ph 8.5) as outlined by (olsen et al., 1954) and p content in the extract was determined using ascorbic acid as reducing agent by a spectrophotometer. available potassium (nh4oac-k) was extracted with neutral 1n ammonium acetate (hanway and heidel, 1952) and estimated by a flam photometer; available sulphur (cacl2-s) was determined by extracting the soil samples with 0.15 cacl2 and sulphur concentration in the extract was estimated by turbidimetric method (chesnin and yien, 1950). yield data collection local aman cultivars such as lothor, lalpyka, kutiagoni, mutha, razashail, sadapajam, lalchikon, sadachikon sadamota, lalmota and moulata were cultivated by the farmers. rice plants from 5 m2 area of the middle of each field were harvested at ground level and threshed. the grains were dried in sunlight and winnowed before weighing and the seed yield was adjusted to 14% moisture content. the descriptive statistics of chemical properties of collected soils were determined. means, maximum, 81 assessment of soil chemical properties and rice yield in tidal submergence ecosystem minimum, standard deviation, coefficient of variation and skewness of yield and soil chemical properties were determined. computations were made using excel software. results and discussion descriptive statistics based on skewness values, grain yield, ph, som, n, p, k and s were normally distributed. a wide range was observed for each soil chemical parameter. the coefficient of variation (cv) values for all selected parameters ranged from 8.77 to 71.04%. notably, a relatively small cv value (8.77%) was observed for ph, while a relatively large cv value was obtained for p (71.04%). soil ph influences the solubility of phosphorus, zinc and many other nutrients (lindsey, 1979). changes in ph due to soil submergence during wetland rice growth may alter considerably the availability of nutrients from those predicted by soils tests based on nutrient extractions from dry soil samples. besides acting as a source of nutrients, soil organic matter also has very important functions related to nutrient availability and retention. these should also take into consideration that the nutrient input from tidal sediments, which may contribute considerably to crop nutrition. others have also reported similar findings at various scales (fu et al., 2010). table 2. statistical summery of grain yield and soil chemical properties descriptive statistics variables mean minimum maximum standard deviation cv (%) skewness yield (t ha-1) 2.71 1.26 3.98 0.621 22.89 -0.08 ph 6.55 5.04 7.58 0.574 8.77 -0.08 som (%) 2.31 1.41 3.35 0.336 14.51 0.05 n (%) 0.113 0.075 0.160 0.020 17.87 0.16 p (mg kg-1) 10.58 0.490 41.15 7.51 71.04 0.95 k (meq/100g) 0.16 0.092 0.230 0.038 23.63 0.20 s (mg kg-1) 18.41 6.52 39.26 7.23 39.27 0.74 spatial variation in soil chemical properties a great variation in soil chemical properties existed across different locations. the mean value of soil ph ranged from 6.03 to 7.07. the maximum soil ph at pinglakhati (pk) of gournadi and the minimum at bibichini (bb) of batagi were recorded (fig. 1). the maximum and minimum values of ph were 7.58 and 5.26; 7.46 and 6.40; 7.18 and 5.60; 7.44 and 5.04; 6.61 and 5.60; and 7.04 and 6.51 at pinglakhati (pk), kutubpur (kt), niamoti (nm), char boalia (cb), bibichini (bb) and dopdopia (dp), respectively. saleque et al. (2010) also reported that most of the delta soil had ph values in the top soil ranging from slightly acidic to moderate alkaline. slight acidity was found in some fields indicates that soil was probably an acid soil. many of alkanline soil reaction, presumably resulting from repeated equilibrium with surface water and ground water that were influenced by sea water carrying neutral and chloride salts. 82 mamun et al. lsd = 0.22; p<0.01 4 5 6 7 8 pk kt nm cb bb dp name of locations s o il p h lsd = 0.18; p<0.01 0.0 1.0 2.0 3.0 4.0 pk kt nm cb bb dp name of locations s o m ( % ) lsd = 0.009, p<0.01 0.06 0.09 0.12 0.15 0.18 0.21 pk kt nm cb bb dp name of locations t ot al n ( % ) lsd = 3.62, p<0.01 0 9 18 27 36 45 pk kt nm cb bb dp name of locations a va ila bl e po ls en (m g kg -1 ) lsd = 0.019, p<0.01 0.00 0.06 0.12 0.18 0.24 0.30 pk kt nm cb bb dp name of locations a va ila bl e k ( m eq /1 00 g) lsd = 3.18, p<0.01 0 8 16 24 32 40 pk kt nm cb bb dp name of locations a va ila bl e s ( m g kg -1 ) fig. 1. comparison of soil properties among the locations. the white and black boxes indicate 2nd and 3rd quartiles. the line between two bars represent the mean value. pk = pinglakhati, kt = kutubpur, nm = niamoti, cb = char boalia, bb = bibichini and dp = dopdopia. the som content was almost similar among locations. the average som varied from 2.10 to 2.48%. the maximum som (3.35%) was recorded from pk and minimum (1.41%) from cb. the locations were flooded twice daily and rich in som. the relatively high som concentration pk and kt soil could be attributed to the prolonged submergence and growth of natural aquatic plants during the period when the soil was flooded. on the other hand, the water logging of tidal soils might reduce decomposition of som, causing higher som concentration. little variation was observed in spatial distribution of total n (%) across the locations. the mean value of total n ranged from 0.09 to 0.13%. maximum total n was obtained from kt and minimum from pk and cb. the critical value of total n in soil is 0.12% (shah et al., 2008). the obtained total n was less than critical limit. there was a great variation in spatial distribution of available p across the locations (fig. 1). the mean value of available p ranged from 3.10 to 12.09 mg kg-1. maximum available p was obtained from kt and 83 assessment of soil chemical properties and rice yield in tidal submergence ecosystem minimum from nm. the critical value of available p in soil is 8.0 mg kg-1 (shah et al., 2008). the obtained available p was much higher than critical limit in some location. tidal flooded soils are replenished with p through tidal sediments, which can contain considerable amounts of total and available p (saleque et al., 2010). the variation was less in available k across the locations. the mean value of available k ranged from 0.13 to 0.16 meq/100g. maximum available k was obtained from nm and minimum from dp. the critical value of available k in soil is 0.12 meq/100g (shah et al., 2008). the obtained available k was much higher than critical limit in some location. saleque et al. (2010) also reported that exchangeable k concentration of tidal soil was high. it might be due to carrying k through tidal water. there was a great variation in spatial distribution of available s across the locations. the mean value of available s ranged from 13.15 to 24.90 mg kg-1. maximum available s was obtained from dp and minimum from pk. the critical value of available s in soil is 10.0 mg kg-1 (shah et al., 2008). the obtained available s was much higher than critical limit in some location. the tidal water contains some amount of k and p. thus the amount of soil k and p were much higher than critical value. however, soil s was also higher than critical value because of higher som content and organic is the main source of s in soil. spatial variation in grain yield the yield of rice varied depending on locations. the average grain yield was 2.56, 2.90, 2.33, 3.06, 2.48 and 2.96 t ha-1 in pk, kt, nm, cb, bb and dp, respectively. the maximum grain yield was obtained from cb (3.98 t ha-1) and minimum from cb (1.26 t ha-1). the minimum and maximum yield at pk, kt, nm, cb, bb and dp were 1.37 to 3.63; 1.77 to 3.75; 1.40 to 3.0; 1.26 to 3.98; 1.54 to 3.26 and 1.48 to 3.92, respectively (fig. 2). however, farmers did not apply fertilizers. it is often impossible to follow recommended practices of nutrient management like nitrogen (n) fertilizer because there is a high risk of surface n losses to floodwater. correlation between selected parameters to characterize the relationships between yield and selected soil chemical properties (ph, som, n, p, k and s), pearson's product moment correlation coefficient was calculated for each property (table 3). the results indicated that rice yield was strongly and positively correlated with ph, k and s, and negatively with som. moreover, no significant correlation was observed between rice yield and n or p. this results support the findings of liu et al. (2014). lsd = 0.33, p<0.01 0.0 1.0 2.0 3.0 4.0 pk kt nm cb bb dp name of locations g ra in y ie ld (t h a-1 ) fig. 2. comparison of grain yield among the locations. the white and black boxes indicate 2nd and 3rd quartiles. the line between two bars represent the mean value. pk = pinglakhati, kt = kutubpur, nm = niamoti, cb = char boalia, bb = bibichini and dp = dopdopia. table 3. correlation coefficients (pearson’s test) of rice yield and soil properties yield ph som n p k s 84 mamun et al. (t ha-1) (%) (%) (mg kg-1) (meq/100g) (mg kg-1) yield (t ha-1) 1 ph 0.371** 1 som (%) -0.157* -0.020 1 n (%) 0.073 0.089 0.863** 1 p (mg kg-1) 0.096 0.321** 0.403** 0.522** 1 k (meq/100g) 0.160* -0.129 0.102 -0.009 0.077 1 s (mg kg-1) 0.293** 0.140* 0.066 0.362** 0.194* -0.129* 1 * p < 0.05 and ** p < 0.01. to determine whether a curve-linear relationship exists between the rice yield and nine soil nutrient parameters, regression analysis with the scatter plot was carried out (fig. 3). the result illustrated that there was no typical curve-linear relationship between the rice yield and soil nutrients, although the yield to ph can be fitted slightly linear equation (fig. 3) very poor r2 values. similar to correlation analysis, these linear regressions confirmed that rice yield increased substantially with soil ph, available k and s, while it showed a slight decreasing trend to soil organic matter. fairhurst et al. (2007) reported that low land rice in delta soil would rarely respond to the application of k. moreover, considerable k input from tidal sediments can contribute to the k nutrition of rice in this area. saleque et al. (2010) also reported that none of tidal soils analyzed was deficient in s for wetland rice and considerable s input from the deposition of tidal sediments could be expected. y = 0.4016x + 0.0846 r2 = 0.1377** 0.0 1.0 2.0 3.0 4.0 5.0 4.0 5.0 6.0 7.0 8.0 soil ph g ra in y ie ld (t h a-1 ) y = -0.2915x + 3.3882 r2 = 0.0248 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 soil organic matter (%) g ra in y ie ld (t h a-1 ) y = 2.2504x + 2.4591 r 2 = 0.0054 0.0 1.0 2.0 3.0 4.0 5.0 0.000 0.050 0.100 0.150 0.200 total n (%) g ra in y ie ld (t h a-1 ) y = 0.008x + 2.6296 r 2 = 0.0093 0.0 1.0 2.0 3.0 4.0 5.0 0 10 20 30 40 50 60 available p (mg kg -1 ) g ra in y ie ld (t h a-1 ) 85 assessment of soil chemical properties and rice yield in tidal submergence ecosystem y = 2.635x + 2.293 r 2 = 0.0256 0.0 1.5 2.9 4.4 0.00 0.05 0.10 0.15 0.20 0.25 available k (meq / 100g) g ra in y ie ld (t h a-1 ) y = 0.0252x + 2.2491 r 2 = 0.0863 0.0 1.0 2.0 3.0 4.0 5.0 0 10 20 30 40 50 available s (mg kg -1 ) g ra in yi el d (t ha -1 ) fig. 3. regression analysis between rice yield and soil properties. this result supports the findings of ilstedt et al. (2003). numerous studies have reported that som is positively and highly correlated with rice yield (pan et al., 2009), while an opposite finding was observed in our study. such unconformity may explain the negative correlation between rice yield and som. low decomposition rate and less microbial activity due to tidal flooding may be the cause of negative relationship between yield and som. conclusion the entire tidal flood prone area was characterized by neutral soil ph, high concentrations of som, p, k and s . low levels of n may be the major factors limiting rice production due to their positive effects on rice yield. on the basis of those results, n fertilizer must be applied but deep placement should be advocated to avoid loss in tidal water. references allison, l. e. 1965. organic carbon. in: c. a. black (eds). methods of soil analysis, part 2. asa, madison, usa, pp. 539-577. bremner, j. m. 1965. total nitrogen. in: c. a. black (eds). methods of soil analysis, part 2. asa, madison, usa, pp. 595-622pp. debnath, m., m. t. islam, e. j. emi, s. hasna, m. h. o. rashid and s. c. smanta. 2013. an effect of fertilizer management practices on the yield of t. aman rice under tidal ecosystem. american journal of agriculture and forestry 1(4): 74-79. elahi, n. e., m. a. h. khan, m. a. i. khan, m. r. islam, m. a. salam, m.a. hossain and a. u. ahmed. 2001. research report of the tidal non-saline sub-ecosystem for the year 2001. ifad planning meeting held on 13 january, 2001, dhaka, bangladesh. fairhurst, t. h., c. witt, r. j. buresh and a. dobermann. 2007. rice: a practical guide to nutrient management, 2nd edn. international plant nutrition institute and international potash institute. international rice research institute. metro manila, 89 pp. fu, w. j., h. tunney and c. s. zhang. 2010. spatial variation of soil nutrients in a dairy farm and its implications for site-specific fertilizer application. soil tillage res. 106, 185–193. gray, l. c. and p. morant. 2003. reconciling indigenous knowledge with scientific assessment of soil fertility changes in southeast burkina faso. geoderma 111: 425–437. 86 mamun et al. hossain, m. a., b. c. roy, s. s. haque, m.a. i. khan and a. w. julfiquar. 2002. potentiality of hybrid rice in the south central region of bangladesh. hybrid rice in bangladesh, progress and future strategies. bangladesh rice research institute, pp: 51-52. ilstedt, u., r. giesler, a. nordgren and a. malmer. 2003. changes in soil chemical and microbial properties after a wildfire in a tropical rainforest in sabah, malaysia. soil biol. biochem. 35: 1071–1078. jalali, m. 2007. spatial variability in potassium release among calcareous soils of western iran. geoderma 140: 42–51. jin, j. y. and c. jiang. 2002. spatial variability of soil nutrients and site specific nutrient management in the p.r. china. comput. electron. agric. 36: 165–172. lindsey, w. l. 1979. chemical equilibria in soils. john wiley & sons inc, new york. liu, z., w. zhou, j. shen, p. he, q. lei and g. liang. 2014. a simple assessment on spatial variability of rice yield and selected soil chemical properties of paddy fields in south china. geoderma 235– 236: 39–47. odum, w. e. 1988. comparative ecology of tidal freshwater and salt marshes. annual review of ecological syatem. 19: 147-176. olsen, s. r., c. v. cole, f. s. watanable and l. a. dean. 1954. estimation of available phosphorus in soils by extraction with sodium bicarbonate. us dept. agric. circular, p. 939. pan, g. x., p. smith and w. n. pan. 2009. the role of soil organic matter in maintaining the productivity and yield stability of cereals in china. agric. ecosyst. environ. 129: 344-348. peech, m. 1965. hydrogen ion activity. in: c. a. black (eds). methods of soil analysis, part 2. chemical and microbiological properties # 9, asa, madison, usa, pp. 914-925. roy, b. c., m. a. hossain and m. a. i. khan. 2003. suitable transplanting time for modern t. aman rice varieties in tidal nonsaline wetland situation in bangladesh. pakistan j. biol. sci. 6(7): 661-665. saleque, m. a., m. k. uddin, m. a. salam, a. m. ismail and s. m. haefelo. 2010. soil characteristics of saline and non-saline deltas of bangladesh. tropical deltas and coastal zones: food production, communities and environment at the land-water interface. p. 145-152. shah, z., w. malik, a. bhatti and h. rahman. 2013. spatial variability of nutrients in wheat plant in semiarid regions of northwestern pakistan. commun. soil sci. plant anal. 44: 2472–2487. shah, a. l., m. r. islam, m. m. haque, m. ishaque and m. a. m. miah. 2008. efficacy of major nutrients in rice production. bangladesh j. agril. res. 33(3): 639-645. virgilio, n. d., a. monti and g. venturi. 2007. spatial variability of switchgrass (panicum virgatum l.) yield as related to soil parameters in a small field. field crop res. 101: 232-239. yamagishi, j., t. nakamoto and w. richner. 2003. stability of spatial variability of wheat and maize biomass in a small field managed under two contrasting tillage. field crop res. 81: 95–108. microsoft word 2 bangladesh agron. j. 2017, 20(2): 11-16 effect of early water deficits on nodulation and effect of early water deficits on nodulation and effect of early water deficits on nodulation and effect of early water deficits on nodulation and nitrogen content of inoculated soybean nitrogen content of inoculated soybean nitrogen content of inoculated soybean nitrogen content of inoculated soybean j.j.j.j. a. adjeteya. adjeteya. adjeteya. adjetey1*1*1*1* and b.and b.and b.and b. n.n.n.n. gggg.... nxumalonxumalonxumalonxumalo2222 1department of crop science and production, botswana university of agriculture and natural resources, p/bag 0027, gaborone, botswana 2discipline of crop science, university of kwazulu-natal, private bag x01, scottsville, pietermaritzburg, south africa *corresponding author, e-mail: jaadjetey56@gmail.com (received:received:received:received: 23 march 2017, accepted: accepted: accepted: accepted: 20 october 2017) keywords:keywords:keywords:keywords: nitrogen fixation, glycine max, water stress abstractabstractabstractabstract the study was conducted at the university of kwazulu-natal (29o 37’ s, 30o 23’ e) from may to november 2012 under controlled environment conditions with three water regimes namely: well watered controls, mild water stress to -1.4 mpa and severe water stress to -2.0 mpa, at the v4 (28 das) and v5 stages (35 das). severe stress significantly reduced no. of nodule and root mass, leaf area, shoot dry mass and uptake, regardless of the stage. mild stress on the other hand had little effect on this parameter as plants recovered on re-watering, to attain values similar to the control treatments. the v4 and v5 stages can recover from mild stress, but severe stress at both growth stages reduces nodulation and nitrogen uptake and this can lead to reduction in production potential of soybean. introductionintroductionintroductionintroduction nodulation and nitrogen fixation begin in the early vegetative stage of the crop but little work has focussed on this stage. it is reported that on the basis of production areas, the crop fixes up to 77 % of all n by crop legumes (herridge et al., 2008). among the several factors affecting nitrogen fixation is water stress, which causes reduced yield and seed quality (candogan and yazgan, 2016). such yield reductions operate through limitation of the symbiotic process resulting in decreased nodule formation and n fixation (serraj et al., 1999). legume productivity has been greatly depressed both by intermittent drought, which could occur at any time during the growing season, but mostly by terminal drought, which occurs when stored soil moisture is depleted resulting in crop senescence (serraj et al., 1999). the response of crops to water deficits is dependent upon the severity and duration of exposure, as well as the physiological stage at which it occurs (desclaux et al., 2000). as the soybean plant grows from the time of flowering to seed enlargement, it shows little ability to compensate for stressful conditions and hence yield reductions are more likely with any stress imposed in this period (khadem et al., 1985). vegetative development of soybean was reportedly less sensitive to drought stress than the reproductive stages (atti et al., 2004). the aim of this study was examine the response of soybean to water deficits at the v4 and v5 stages which occur about 21 and 45 days after sowing depending on growing conditions (castell, 2010). although nodulation begins about 14 days after sowing i.e. the v1 stage, there is very little nitrogen fixation at the stage. nitrogen fixation increases greatly during the v4 and v5 stages where nodules are large and active (staton, 2011). since nodules are active at these stages, it is 12 adjetey & nxumalo important to examine how water deficits during that time impact on overall nodulation potential and nitrogen content of the crop. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the study was conducted at the university of kwazulu-natal (29o 37’ s, 30o 23’ e) from may to november 2012. soybean cultivar pan 1652 which matures in 120 days was used. the soil was obtained from a site at the university experimental farm where no fertilizer had been applied for a few years prior to the study. a commercial preparation of bradyrhizobium japonicum strain w74 was used as a soil inoculants. the plants were grown in 1l pots each containing about 1kg of soil. all pots were seeded and thinned to one plant per pot about one week after emergence. the plants were grown in a growth room under well watered conditions and water stress treatments commenced at the v4 and v5 stages i.e. 28 and 35 das, respectively. the day/night temperatures in the growth room were 28 / 20 oc respectively, the photoperiod was 14h day length and relative humidity was 60%. the experiment was a factorial combination of two vegetative stages (v4 and v5) and three water treatments in a completely randomised design with six replications. the water treatments comprised of a well-watered control with leaf water potential of -0.3 mpa, a mild stress in which water was withheld until the leaf water potential dropped to -1.4 mpa and a severe stress in which water was withheld until the leaf water potential was -2 mpa. the water potential measurements were taken in the afternoon on the last expanded leaf, using a pressure chamber (martińez et al., 2013). in each measurement, a young fully expanded leaf was excised for the plant, covered in a plastic sheet and inserted into the pressure chamber. the gas connected to the pressure chamber was then opened to create pressure in the chamber. a hand lens was used to observe the excised section of the exposed leaf petiole. the water potential was recorded when a water bubble was observed to be exuded from the leaf petiole. after every stress treatment the plants were re-watered and leaf water potential approximating -0.3 mpa was maintained till the final harvest. plant sampling started at the beginning of the reproductive stage (r1 i.e. 55 das) when soybean had initiated flowering. the leaf area was measured using a portable leaf area meter (li-3000, li-cor biosciences) equipped with an li-3050a belt conveyor. number of nodes r and shoot dry mass was determined by drying at 70 oc for two days. plant tissue nitrogen concentration was determined by the dumas combustion method using a tru spec cn – elemental analyzer (leco corporation). nitrogen uptake was then calculated as a product of above ground dry weight and tissue nitrogen concentration [i.e. nitrogen uptake (g) = dry mass (g) x n (%)/100]. the soil moistened with water and carefully removed from pots and the soil was washed off leaving clean roots. the total nodule number, nodule mass and root mass were determined. results and discussionresults and discussionresults and discussionresults and discussion nodule number, dry mass and root mass were significantly lowered (p< 0.01) by severe water stress to – 2.0 mpa, compared to the other treatments (fig. 1). there was little difference in response to severe stress (p> 0.05) whether it was imposed at the v4 or v5 stages. 13 effect of early water deficits on nodulation and nitrogen fig. 1. effect of water deficits on nodule mass (a) nodule number (b) and root mass (c) of soybean grown in controlled environment conditions. severe water stress significantly reduced (p< 0.01) number of nodes, shoot dry mass and leaf area (figures 2 and 3). plants which were stressed to -1.4 mpa were not different from the well watered controls but severe stress had a more detrimental effect. the effect was similar whether it was imposed at the v4 or v5 stage. there was no interaction between water stress treatments and the stage at which they were imposed. there was no significant difference in shoot nitrogen concentration in respect of degree of stress or stage of application (p> 0.05), neither was there any interaction between the two factors. however, nitrogen uptake was significantly reduced (p<0.001) by the severe water stress (fig. 4). plants stressed to -1.4 mpa was comparable with the well watered ones terms of in uptake of nitrogen. fig. 2. number of nodes (a), shoot dry mass (b), and leaf area (c) of soybean grown under well watered condition, mild water stress, and severe water stress. 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 contol mild stress severe stress n o d u le m a ss n o d u le m a ss n o d u le m a ss n o d u le m a ss water treatments water treatments water treatments water treatments v4 v5 0 10 20 30 40 50 60 n o d u le n u m b e r n o d u le n u m b e r n o d u le n u m b e r n o d u le n u m b e r water treatments water treatments water treatments water treatments v4 v5 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ro o t m a ss ( g ) ro o t m a ss ( g ) ro o t m a ss ( g ) ro o t m a ss ( g ) water treatments water treatments water treatments water treatments v4 v5 0 5 10 15 20 25 30 n u m b e r o f n o d e s n u m b e r o f n o d e s n u m b e r o f n o d e s n u m b e r o f n o d e s water treatments water treatments water treatments water treatments v4 v5 0 2 4 6 8 10 12 sh o o t d ry m a ss ( g ) sh o o t d ry m a ss ( g ) sh o o t d ry m a ss ( g ) sh o o t d ry m a ss ( g ) water treatments water treatments water treatments water treatments v4 v5 0 500 1000 1500 2000 2500 le a f a re a m le a f a re a m le a f a re a m le a f a re a m 22 22 water treatments water treatments water treatments water treatments v4 v5 a b c b a c 14 adjetey & nxumalo fig. 3. effect of water deficit imposed at the vegetative stages left = controls, right = severe stress to fig. 4. effect of water deficits on nitrogen concentration (a) and nitro grown under controlled environment conditions. of six plants. the results suggest that severe stress led to significant decrease in no (fig. 1) and is consistent with those of serraj and sinclair (1998) with soybean under field and greenhouse conditions. rhizobium legume symbiosis establishment is reportedly very sensitive to water deficit (serraj et al., 1999). the relatively small difference between control and mild stress (figure 1a and 1b) for nodule number and dry mass is due to the formation to recover quickly from moderate water stress. fellows nodules of soybean were able to recover from water stress of watering. 0 0.5 1 1.5 2 2.5 3 control mild stress severe stress n it ro g e n c o n ce n tr a ti o n n it ro g e n c o n ce n tr a ti o n n it ro g e n c o n ce n tr a ti o n n it ro g e n c o n ce n tr a ti o n water treatments water treatments water treatments water treatments effect of water deficit imposed at the vegetative stages ((((v4 and v5) of soybean. left = controls, right = severe stress to -2.0 mpa. effect of water deficits on nitrogen concentration (a) and nitrogen uptake (b) of soybean under controlled environment conditions. each value is derived from mean (± the results suggest that severe stress led to significant decrease in nodule number and dry mass 1) and is consistent with those of serraj and sinclair (1998) with soybean under field and legume symbiosis establishment is reportedly very sensitive 1999). the relatively small difference between control and mild stress (figure 1a and 1b) for nodule number and dry mass is due to the ability of the nodule formation to recover quickly from moderate water stress. fellows et al. (1987) reported that nodules of soybean were able to recover from water stress of -1.7 mp within 12 hours of re v4 v5 0 0.05 0.1 0.15 0.2 0.25 0.3 control mild stress severe stress n it ro g e n u p ta k e n it ro g e n u p ta k e n it ro g e n u p ta k e n it ro g e n u p ta k e water treatments water treatments water treatments water treatments v4 v5 a b gen uptake (b) of soybean ±se) dule number and dry mass 1) and is consistent with those of serraj and sinclair (1998) with soybean under field and legume symbiosis establishment is reportedly very sensitive 1999). the relatively small difference between control and mild ability of the nodule . (1987) reported that 1.7 mp within 12 hours of rev4 v5 b 15 effect of early water deficits on nodulation and nitrogen the response of the above ground parameters (fig. 2) are consistent with those reported from previous studies (sionit and kramer 1977). the decrease in leaf area from the severe water stress plants (fig. 2d) was probably a major cause of decreasing nodule number (fig. 1a), nodule mass (fig. 1b) and possibly n2 fixation. a decrease in leaf area is associated with a decrease in the photosynthetic capacity of the plant and hence supply of assimilated to the nodule bacteria. serraj et al. (1999) reported that a decline in soybean n2 fixation under drought stress is associated with decreased photosynthesis. the well watered plants with heavily branched growth habit contributed to the high above ground parameters like leaf area, shoot dry mass and number of nodes. the plants that were subjected to water stress at both stage v4 and v5 were not well branched. at stage v4 severe stress lowered the number of nodes more than in v5 (fig. 2a). kadhem et al.(1985) reported that water stress affected node number per plant and pods per node but also found that the effect varied among cultivars which interacted with timing of drought stress. the nitrogen concentration data ranged between 2 and 2.5 % amongst water treatments. however, the n content values were lowest for the severe stress and highest for the controls suggesting that those plants that were water stressed severely did not fix enough nitrogen for biomass production compared to the non-stressed ones (fig. 4). conclusionconclusionconclusionconclusion at the early vegetative phase nodulation is tolerant to mild stress and subsequent nitrogen fixation can resume at a normal rate. however, if soybean is severely stressed the process of nodulation and nitrogen fixation is reduced irrespective of the vegetative stage at which it is imposed. this has a negative effect on nitrogen content and hence potential for increased productivity. severe water deficits during the vegetative stage can, therefore, be as important as those in the reproductive phase in terms of their potential for impacting on the productivity of soybean. referencesreferencesreferencesreferences atti, s., r. bonnell, d. smith and s. prasher. 2004. response of indeterminate soybean (glycine max (l) merr.) to chronic water deficits during reproductive development under greenhouse conditions. can. water res. j. 29: 209-222. candogan, b. n. and s. yazgan. 2016. yield and quality response of soybean to full and deficit irrigation at different stages of growth under sub-humid climatic conditions. j. agric. sci. 22: 129-144. castell, s. 2010. soybean physiology: how well do you know your soybean. www.soybeanstation.org. desclaux, d., t. huynh and p. roumet. 2000. identification of soybean plant characteristics that indicate the timing of drought stress. crop sci. 40: 716-722. fellows, r. j., r. p. patterson, c. d. raper jr. and d. harris. 1987. nodule activity and allocation of photosynthates of soybean during recovery from water stress. plant physiol. 84: 456460. herridge, d. f., m. b. peoples and r. m. boddey. 2008. global input of biological nitrogen fixation in agricultural systems. plant soil. 311: 1-18. 16 adjetey & nxumalo khadem, f. a., j. e. specht and j. h. williams. 1985. soybean irrigation serially timed from r1 to r6. i. agronomic responses. agron. j. 77: 291–298. serraj, r. and t. r. sinclair. 1998. soybean cultivar variability for nodule formation and growth under drought. plant soil. 22: 159-166. serraj, r., t. r., sinclair and l. c. purcell. 1999. symbiotic nitrogen fixation response to drought. j. exp. bot. 50: 143–155. sionit, n. and p. j. kramer. 1977. soybean genotypic differences in sensitivity of symbiotic nitrogen fixation to soil dehydration. plant soil. 133: 31–37. staton, m. 2011. evaluating soybean nodulation. michigan state university extension. msue.anr.msu.edu/news/evaluating_soybean_nodulation. downloaded 17 august 2017. microsoft word final.doc � �������� ��� �������������������������� ��� !�"�#$��! ��� !�"�#$��! ��� !�"�#$��! ��� !�"�#$��! ����%&��'��!'�'!�(��)�')�%�)#�*)++,�����%&��'��!'�'!�(��)�')�%�)#�*)++,�����%&��'��!'�'!�(��)�')�%�)#�*)++,�����%&��'��!'�'!�(��)�')�%�)#�*)++,��������� ���� "��% � ���-..�/���������%� �������0 1� �����"��%��) ��/"��% � ���-..�/���������%� �������0 1� �����"��%��) ��/"��% � ���-..�/���������%� �������0 1� �����"��%��) ��/"��% � ���-..�/���������%� �������0 1� �����"��%��) ��/���� �������� ��� 02-�3����� �� 2 �)� 303-3�� $� � 4���0����-3 � �� � ���-..�/�5�/�0��2�/� 6�7�1� � ��6�7�1� � ��6�7�1� � ��6�7�1� � ��%1��3�4�3�3��8� 0�30� �� 0��7�� �� ����2� �3������� ���� �9 3 �23�9 3 �23�9 3 �23�9 3 �23���� ���� ' ���:4� 0/��3�1� �2���-23����3� 3 �� � �� 2 � ;0�����;�*0���' �23��� 02-�3����� �� 2 � %3�30���� ��/�� �� 6 �� �2 � 0� �0��� ��90� �� ��� �;� ���������� ���� ��������� 08�� �0;;� ��3� 1��3� 4�3�3�� 8� 0�30� � ����)� %�����������<�� ���)� %�������������� ���)� %�������������� ���)� %�����������=� ���� ��2��� 2-�308� � 1� �� 0�2�-���� � � 3 ��3/��3� 8� 0�9�� �0��3 ���:4� 0/��3�����)�%������������� ��� 0��0;02��3�7�/� ���-/9� ��;�80�� � �������� �2�/4� ���3����2���2-�308� ������3 � ���1�8� 0�30� � -2 �� ����)�%�����������<�� ���)�%��������������������)�%�����������=��"�:0/-/��-/9� ��;�3-9� �4���3��� �>��� ���� >����� 3-9� � ����3 � ��>���� ���� �>���� 2/��� 3-9� � �0�/�3� � �>���� ���� >���� 2/��� 0��080�-���3-9� �1�0� 3���<���>���������<=��������3-9� �70������=��=�����������3� ����� 1� � �2� ���� ; �/� ���)� %�����������=� �0��� �������� ���� ��������� � 4�2308��7� 1 ���� � ��2��� 2-�308� � ��8�� /0�0/-/� 8��-� �� ��� ������� ���)� %�����������=� �-3� 70��������2���2-�308� �97�����=�������������?��0���31��2�� �2-308��7�� �������0� � 3� ��3�0�2�/��������������������>�<���'@�� ��������������)�%����������������� ���� )�3 ��-230��)�3 ��-230��)�3 ��-230��)�3 ��-230������ ���� %1��3�4�3�3�� �)4�/���9�3�3� �+��� �����2 ��4� �2���;� 2��� 0� � ����/�����>��9�����0��� 3�� 3 �� ;�/0�7�$��8��8-��2������ �� �����/��0��� � ����������>������ 0 � ��@��� 3 0 ��/� 3� 0/4� 3��3� 3-9� �2 �4 ��;3� �4�3�3���%����-/��3-9� � -/������2� �8���"��0 �3��� 2-���3-/��� �!����������� ! ����� ;�� � 1��3� 4�3�3�� � � �� 02 � 0�� ��2� �3����� ' �� 2 �4� 2��� ���43� 3�� �� 10��� ����� �;� ��80 ��/��3��� 2���030�� � ���� � �1� ��� /� �0���� � �� � 103 � 4�� � �0� � �;� �0/03��� ;� 30�037� ���� 0����a-�3��/�0 3����#$��������103 ���1�0�4-3 ���)3�4��7 ���803��� ����0��3 ����0�7��0�3�4�� �/��� ;���� 0�� �������� �� ' �� �8� ���� 70���� �;� 1��3� 4�3�3�� 0�� �������� � 0 � ���7� =���� 3�� � 4� � �23� �� ���%�� ������� 2�/4� ��� 3�� 3 �� �8� ���� 1� ��� 70���� �;� ���=� 3�� � 4� � �23� �� � �!�� �������' ��� �������3�3���4 ��-230����;� 1��3�4�3�3��0���������� �� ����2 �� 0�����7�97���7� �-�� 3�� ��2@� �;� ����� 8� 0�30� �� ���308��7� ����� 2 �4� ��30���� 4� 3� � 8� 3� �� � �� 0�2 �� 0��� 0 0��30���;�20�030� �3����3 ��� �1� �3��� �1��3 � ��2� �2 �4 �� 02���1 ��3��4�3�3���/�0.���32��� ����3�2 � �23� �����70�����;� 1��3�4�3�3��8� 0���10���7��/����3 ��8� 0�30� ��,���8��3�������==<b� ����7/��� �==���� ' �� �������� � �� 02-�3��� �� �� 2 � )� 303-3�� ����)�� � � �2��3�7� ��8���4��� �8� ��� ��1� 8� 0�30� � �;� 1��3� 4�3�3��103 � 70���� 4�3��30��� �;� �>���� 3c ��� 9-3� 3 � �� 8� 0�30� � � �� ��3� 7�3� �8�0��9��� ;� � ;� /� � �;� 3 �� $ �33������ *0��� ' �23 �� ' �� 3�3��� � ��� �;� $ �33������*0���' �23 �0 �� 30/�3���� �-���������� ��1 02 �0 ��9�-3���?��;�3�3��������� ����;� 3 �� 2�-�3 7�� �;3� � � 8� 3� �;� '��/��� 3 � �� 0 � 10��� 2�4�� 3�� � �1� 0� � 70���0��� 1��3� 4�3�3�� 8� 0�30� � 9�2��� ;� /� � �;� 3 0 � � ��� 2-�308�3�� ��2��� 2-�308� � �;� 1��3� 4�3�3�� 1 02 � 0 � 4�� � 70���� ��' �� 0� �70���0��� 1��3�4�3�3��2��� -44��/��3�� � ������� �2���;� ;���� ;� �/�0��7� /� �0����;� /� ��;� 0��7� ��0����&03 �3 0 �80�1��3 ��4 � ��3� 3-�7�1� �2���-23���3��;0����-3�3 �� 4� ;� /��2���;� �2��3�7���8���4��� 0� �70���0���8� 0�30� ��;� 1��3�4�3�3��0��3 �� 0��7� ��0���� ���� ���� ��� % � ���-..�/���3����� "�3�"�3�"�3�"�3� 0�� �����"�3 �� 0�� �����"�3 �� 0�� �����"�3 �� 0�� �����"�3 �� ���� ���� ' �� �:4� 0/��3� 1� � 2���-23��� �3� � �� 2 � ;0���� �;� *0��� ' �23� �� 02-�3��� �� �� 2 � %3�30���� ��/�� ��6 �� �2 � 0��0�����90� �� ����;����������������������' �� �0���;� 3 0 � 0���� ��� 9����� �3����d��=������20�02�0����3��� 08���0;;� ��3� 1��3�4�3�3��8� 0�30� �����)�%1��34�3�3�� <�� ���)� %1��34�3�3����� ���)� %1��34�3�3����� ���)� %1��34�3�3��=� ���� ��2��� 2-�308� �� 1� �� 0�2�-����� �3 ��3/��3�8� 0�9�� ��' ��3 0���1� ���0���-3�0���� ����/0.���2�/4��3��9��2@��� 0���103 � ;�� �4�02�30�� ��(0����;� 1��3�4�3�3�� �����2/������2-330�� �103 ����������� �1� ��4���3������ �<�#�8�/9� ��������������#�8�/9� �������/�0�3�0�0��� 4�20����;�<��2/�:����2/�� � 30�0.� � �3�3 �� �3���;��<���>������@�� �����;�#���6�0��3 ��;� /��;�����3 04��� -4� �4 � 4 �3���'%��� ����/0�3���;�4�3� � �"����� � 4�2308��7� ������103 � 2�1�-������ 3��c �� ���� �0/���� 3��c ��� ' ��;-����/�-�3��;��0/���2�1�-����'%���e�"���������c��f ���1� ���44�0���� �9� ����0���;0���� ����� 4 �4� �30���� ' �� �/�0�0��� �;� ��� ����"���1� � 0��� � � ��� �3� <�� ��7 � �;3� � 4���30��� �g����� ) 0��30���� 1���0���� �� 3 0��-4� ���� 0� �23020�� � 1� �� �44�0��� � � 1 ��� �a-0 ��� )3� 1� � � 8� 3����;3� ��>��g���1 ��� 3 ��80�� �1� �� 3���� 3��� 7�� �9 �1��2��� �����g0;;� ��3�8� 0�3��� 2 � �23� 0 302 �����70����2��3 09-30���2 � �23� �1� �� �2� �����' ��2����23�����3��1� ������7.��� 3�30 302���7�����/��� �1� �� �4� �3���0���+%g�3� 3��3�>?���8����;� 0��0;02��2��� �� �� -�3 �����g0 2 0���� -�3 �����g0 2 0���� -�3 �����g0 2 0���� -�3 �����g0 2 0������ � �8� �����-/9� ��;�80���� ����3 ��;�3 ��80�� c�4���3�����1�0� 3��;��9�8�h� �-���90�/� c4���3� �0�����������������������1� �� �1�� 0��'�9���������� 3 �� 8� 0�30� �1� �� �1��� 0���302��� �-/9� ��;�80�� ��*�1�8� �����)�%1��34�3�3����1� �/� ���-/9� ��;�80�� ��������1 02 �1� ��3� 4� �3�����)�%1��34�3�3��=�� �2�/4� ���3����2���2-�308� ��(� 0�30���0��9 ��2 0���/0� 3�9���-��3�� 3 ��8� 0�3���2 � �23� 0 302 ��' �� � -�3 ��;� 3 ���:4� 0/��3�� �� 0���� ��/��3�103 �3 ��;0��0�� ��;� *� �0�� ��==>��� ' �� 8� 0�37� ���)� %1��34�3�3���� 1� � �2� ���� 3 �� 0� � 3� ����3 � �;� 80��� ��=����� 2/��� ' �� �3 � � /��� �� 8� 0�30� � ����)� %1��34�3�3��<�� ���)� %1��34�3�3����� ���)� %1��34�3�3��=�� ��� �2���� 0� � 3� ����3 ��;�80�� � ������9�31����������������<��2/�1 0���� ��2��� 2-�308� � ��8�� 3 �� ��1� 3� ����3 ��;� 80��� �����>��2/���' �� 0� � 3�1�0� 3� �;� �9�8��� �-��� 90�/� c4���3�1� �;�-���; �/����)�%1��34�3�3�������=>�@��4���3����1 02 �1����3�4� �103 �3 �3� �;����)�%1��34�3�3��=�����>�@��4���3����������1� 3�; �/���2���2-�308� ����<>�@��4���3������ � '�9������� �8� ���� �-/9� � �;� 80��� 4���3���� ����3 � �;� 3 �� 80�� � ���� 1�0� 3� �;� �9�8�h� �-��� 90�/� �4���3��� �;�/��� �� 8� 0�30� � ���� ��2��� 2-�308� � �;� 1��3�4�3�3��1� � � �1�� 0�� 0��7� ��0���0��31�� �� �� � (� 0�30� � #����;�80�� � 4���3��� +���3 ��2/���;�80��� &3���@����;��9�8��� �-��� 90�/� �4���3��� ���)�%1��34�3�3��<� <�>>�� ������� ������ ���)�%1��34�3�3���� ������ �=������ ��=>�� ���)�%1��34�3�3���� ������ ����<��� ������ ���)�%1��34�3�3��=� ������ �������� ���>�� ��2���2-�308� � <����� ����>��� ��<>�� +%g����>�� ����� ��>�� ����� $(��?�� ���<� ����� <���� � ����3�4�4-��30����70��������70����2��3 09-30���2 � �23� ��;� 1��3�4�3�3��8� 0�30� �1� ��4 � ��3��� 0�� 3 �� '�9����� i� ��� #-/� 02���7� 3 �� /�:0/-/� �-/9� � �;� 3-9� c4���3� �>��� ���� >���1� �� �2� ���� ; �/� ���)� %1��34�3�3��=� �0��� �������� ���� ��������� � 4�2308��7������� ��1� 3� �>� �� ;� /��2���;�%1��3���3�3��0��*0��7�� ��� �-/9� ��;� 3-9� c4���3�1� � �2� ����; �/���2���2-�308� � �'�9������� � ��a-������*�0�� ��=���� �� �� �4� 3���3 �3�3 ���-/9� ��;�3-9� c�4���3�8� 0���; �/������3������<�1 0���%0��0a-����=�>�� ;�-����; �/������3��<����� � '�9������� #-/9� ��;�4���3 �/����3-9� �4���3����0��080�-���3-9� �13����������3 ��;�0��080�-���3-9� � �;�/��� ��8� 0�30� �������2���2-�308� ��;� 1��3�4�3�3��1� �� �1��0�� 0��7� ��0���0��31�� �� ��� ' ��3� #����;� 4���3 � /��� #����;�3-9� �4���3��� )��080�-���3-9� �13�� ���� +���3 ��;�0��080�-��� 3-9� ��2/�� �������� �������� �������� �������� �������� �������� ���)�%1��34�3�3��<� ��>� ���� >��� �����>� �=����� ���>�� ���>�� ���)�%1��34�3�3���� ��>� >��� >��� ����<�� ��=���� ���>�� ���>�� ���)�%1��34�3�3���� ���� ���� ���� ����>� ������� ������ ���<�� ���)�%1��34�3�3��=� ���� >��� >��� �<���>� ����<=� �>���� �>���� +�2���$-�308� � ���� ���� ���� �>��>� �<����� ���>�� ���>�� +%g����>�� #%� #%� #%� ���=� ��>=� ��=�� ����� $(��?�� ����� >��<� >���� ������ >��>� >�>�� ����� � )��080�-��� 3-9� �1�0� 3� ��<���>�����������<������� ����3 ��;� 0��080�-��� 3-9� � ����>���������>�� 2/��� �0�/�3� � �;� 0��080�-��� 3-9� � ���>�� 2/���������� 2/�� ���� � 7�/�33� � 2��3��3� �;� 0��080�-��� 3-9� � ��<��=� ���� ������ ?�� 1� �� /�:0/-/� 103 � ���)� %1��34�3�3��=� �0��� �������� ���� ��������� � 4�2308��7�� +�2��� 8� 0�37� ��� � ��1� � 8��-� � 0�� ���� 3 � �� 4� �/�3� b� 3-9� � 1�0� 3� ��>��>��������<��������������3 ��;�3-9� ���>���������>����2/����0�/�3� ��;�3-9� ��>����2/����� >����2/������� 7�/�33� �2��3��3��;�3-9� ������������������?��;� �� � 4�2308��7���' �� � -�3 ��;� 3 ��4 � ��3� 3-�7�1� �� 0�� �� ��/��3�103 � 3 �� �4� 3� �;�(� 2��2���� � �3� ���� ��=�<���' ���3 � � /��� �� 8� 0�30� b� ���)� %1��34�3�3����� ���)� %1��34�3�3���� ���� ���)� %1��34�3�3��<� 1� �� -4� 0� � 3 ��� ��2��� ����� ' �� 8� 0�37� ���)� %1��34�3�3��=� �1��� 3 �� /�:0/-/� 3-9� � 70���� ��=��=�3� ��������������3� ������;����1���97����)�%1��34�3�3������>�=�������������3� ����� 0�� 9�3 �3 ��7�� ��'�9�������+�2���2-�308� � �1���3 ����1� 3�70�����=�>��3� ��������=�=��3� ������' �� 70����0�2 �� ����8� ���2�������1� �����=�������������?��� � '�9��� ���g0�/�3� � �;� 0��080�-��� 3-9� �� � 7�/�33� � 2��3��3� �;� 0��080�-��� 3-9� �� 70���� �;� 3-9� � �;� /��� ��8� 0�30� �������2���2-�308� ��;� 1��3�4�3�3������70����0�2 �� ���8� ���2���2-�308� � 3� 3���0�� 0��7� ��0���0��31�� �� �� � ' ��3/��3� g0�/�3� ��;�� 3-9� ��2/�� g 7�/�33� � 2��3��3��3-9� ��� �?�� '-9� �70����� �3� ����� ,0����0�2 �� �� �8� ���2��� �?�� ����� ��� ����� ��� ����� ��� ����� ��� ����� ��� ����� ��� ����� ��� ����� ��� ���)�%1��34�3�3��<� ����� ����� ���>��� ����>� ���<=� ������ ����=� �=��=� ���)�%1��34�3�3���� ����� ��>�� ����>�� ������ �>�=�� ������ <����� ������ ���)�%1��34�3�3���� ��>�� ����� ������� ���>�� ������ ����<� �=�=�� ������ ���)�%1��34�3�3��=� >���� >���� ������� ������ �=��=� ������ ����=�� ������� +�2���$-�308� � ��>�� ����� �<��=�� ������ =�>�� =�=�� �� �� +%g����>�� ���<� ���>� ����� ���>� ���>� ����� �� �� $(��?�� ���>� ��>�� ����� ���>� ����� ���>� �� �� �� ' ���3 � � 3� 3��� 8� 0�30� � �������=�h������?�/� �� 70�����8� � ��2��� �����' � �� � -�3 �1� �� 0/0�� � 3�� 3 �� ;0��0�� � �;� �� ��� ���� %0��0a-�� �������� %0��0a-�� � �3� ���� ��=����� �� -2�� �3� ���� �<� % � ���-..�/���3����� ��==��������7/����==����*� �0������"��������==��������� � ������� ����==>���)3�0 ����3���� 3 �3� 3 �� 4�3��30��� 70���� �;� 3 � �� 4�3�3�� 8� 0�30� � 0 � ����>� 3� ���� 9-3� ���� 3 �� 8� 0�30� � 4 ��-2��� ��1� � 3-9� � 70���� 0�� 3 �� 0��7� ��0���� )3� /0� 3� 9�� �-�� 3�� 4 �8�0�0��� ��1� � 3�/4� �3�� �0��� #�8�/9� �3�� �9 -� 7�1 ����8� ����3�/4� �3��1� �9���1����$�0��9�3 �3 ��� �10��� �� ���� %1��3�4�3�3��� �1 �9� 3�1 � ���8� ����3�/4� �3��0 ����2��6�7���=������� ' �� 0� � 3�� � �������3�0�2�/��; �/����)%1��34�3�3��=�1� � 0� � 3��'@��������� �������� '@�� ��><��� ����� �0��� �������� ���� ������� � 4�2308��7� 9-3� �3 � � /��� �� 8� 0�37� �0�� ��3� 4� ;� /�10��� 9-3� 0� � � �3�� 3 ��� ��2��� 2-�308� � �'@����������� ���� ����'@��������=�� � ����� �'�9�������� � '�9��� ��� � 30/�3��� ��3� 0�2�/�� �;� /��� �� 8� 0�30� � ���� ��2��� 2-�308� � �;� 1��3� 4�3�3�� 1� � 2-�308�3���0�� 0��7� ��0���0��31�� �� �� � ' ��3/��3 � '-9� �70�����3� ����� j � �)�2�/���'@�� ����� #�3�)�2�/���'@�� ����� �������� �������� �������� �������� �������� �������� ���)�%1��34�3�3��<� ���<=� ������ �>��>�� �=<���� �<<�>�� ��=���� ���)�%1��34�3�3���� �>�=�� ������ ���<>�� ���>>>� ���<>�� �>>>>>� ���)�%1��34�3�3���� ������ ����<� ����=�� �<����� ����=�� ������� ���)�%1��34�3�3��=� �=��=� ������ �=����� ���<��� ������� ��><��� +�2���$-�308� � =�>�� =�=�� �=����� �=��=���� ������� ����=�� � ���� $��2�0��$��2�0��$��2�0��$��2�0������ ���� ' �� � -�3 � �;� 3 �� 4 � ��3� 3-�7� 0��02�3��� 3 �3� ���)� %1��34�3�3��=� ���� ���)� %1��34�3�3���� 1�-���9�� -03�9��� 1��3�4�3�3��8� 0�30� �;� �2-�308�30���0�� 0��7� ��0����;��������� ������ ���� ��;� ��2� ��;� ��2� ��;� ��2� ��;� ��2� ���� � ���/� 6�� +��� ���>�� %1��3� 4�3�3��� � ���02� 4 ��-230���� !��0���� �8�0��9��� ; �/�� 334�cc� 111��2�3�� �c�33 ��4-9c 1��3�4�3�3�� 3/��� ����7/��� �==��� ���-��� ��4� 3� �;� 3 �� '-9� � $ �4 � �� �� 2 � $��3 ��� �==��=���������� � �� 02-�3����� �� 2 �)� 303-3�����7��94��j�.04���44�������<�� �� -2���"���������!���������d������� 2� �����+��+��'���������==���� ��0/0�� 7�,0����' 0������%1��3� ��3�3��� #� 3 � �� � 0�0440�� � ���3� $ �4 � �� �� 2 � ���� ' �0�0��� $��3 �� �#��$�'$��� �� �� 2 � � -�3 �4 � ��3���0���� � 0� ��;�1� @0���4�4� ���%f�#��$�'$���==���44�>��<��� ��%� ��������� � ���-� �;� %3�30 302 ��� ������ ,�� � ���@� �;� �� 02-�3��� %3�30 302 � �;� �������� �� �������� � ���-� �;� %3�30 302 �� %3�30 302 � g080 0���� "0�0 3 7� �;� �����0���� j�83�� �;� 3 �� ���4��k ���4-9�02��;��������� ��g �@��4���>�� �� � ���f��6������6������ ����==>��!��;� /��8��-�30����;�4 �/0 0��� 1��3�4�3�3���)4�/����9�3�3� �� 8� 0�30� �;� �3 �� �0�;���-�9-�����-4���� ��;�6��� ���0��! 0 ���)��0���$��3��� 0����� ����� � -44��/��3���������� �#$���0��3 02 �#-;;0����$�-�20����������' ��f ���;�j"�$ �4 �0��g�8���40���$�-�3 0� ��$� �� 3-�7� >��)/4 �8��� � 0 3��2��3��80 � �0�� 1��3�4�3�3��� ����� g�� ���>�� %1��3� ��3�3�� � �;0���� �� 02-�3��� "� @�30��� ���� �� �2�� $��3 �� ���"�$�� �� #�30�����)�;� /�30����� �2��;� �(��-���������� 02-�3���)�1��%3�3��f�08� 037��-9�0 � �� ��� �� ;� /��2���;�%1��3���3�3��0��*0��7�� ��� �!� � ���� ������ 02-�3��! ���0.�30����� ������ ���� ������ 02-�3��! ���0.�30��� �;� 3 ��f�03��� #�30�� ���-����%3�3������<���� �!�%�2 �3� 0�3���/���)3��7�� �!� � ���� ���� �� 02-�3�� ! ���0.�30����� ������ �!� � ��-230��� ,�� � ���@�� �� 02� g�3�� f�03�� %3�30 302 �g080 0���� �!����/���)3��7��>���=>�� � ��a-�����"���������*�0����=����%3-�0� ����3 ��2�/4� �308��/� 4 ����02���2 � �23� �����3 �� 70�����;�3 �� �8���8� 0�30� ��;� 1��3�4�3�3����������� �*� 3��������������� *� �0��"��"�� ����"��������"��������==����;;�23��;� 80���4� 3 ���� 3 ��� �13 ����� 70�����;� 3 ��� 1��3�4�3�3��8� 0�30� ���������� ����%20��)������ ���=�������������� *� �0���"��g���==>��%3-�7����� �13 ��70�����2�� -/� k �4 �;� ��2������ 3� �����;���� 1��3�4�3�3�� �)4�/���� 9�3�3� � +�/��� ����374� �� "�%�� 3 � 0 �� g�4� 3/��3� �;� *� 302-�3��� �������� � �� 02-�3���f�08� 037��"7/�� 0�� ��4��=�� �� ����"���������"��������%0��0a-���������%3-�0� ����� �13 ��70�������� 3� �����;� 1��3�4�3�3��� � 0�;�-��2��� 97� 8� 0�37� ���� 30/�� �;� � 8� 3��"�� %��' � 0 ��g�43�� �;�*� 302-�3����������� � �� 02-�3���f�08� 037��"7/�� 0�� ��44������� 6�7�g������=����$ �4�����4 ��-23��0�� 3�������3�2 �4 ��' �402���4 ��-23�)� 303-3���+�������4���>��� %0��0a-�� "�� ���� ��� '�� "�� *� ��-..�/��� ���� ��� *�0��� �=���� j �13 � ���� 70���� �;� 3 ��� 0� � 70���0��� 1��3�4�3�3������374� ���������� ������ 02�����������=���>��� %0��0a-��� "�� ��� ��� �=�>�� %3-�0� � ��� 3 �� /� 4 ����7�� � �13 � ���� 70���� �;� �/�� 1��3� 4�3�3�� ����374� �� "�� %2�� ��� 02-�3��� 3 � 0 �� g�43�� �;� *� 302-�3��� �������� � �� 02-�3��� f�08� 037��"7/�� 0�� �� (� 2��2���� �*�� g�� g�� +�� ��/�0���� #�� ��� +���� ���� �"�� � ���� #�3��� �=�<�� $�/4� 0 ��� �;� 1��3� 4�3�3�� �)�4�/���� 9�3�3� � +��� 2-�308� � 0�� 3 �� /-�0204��037� �;� 8� �� ����� $�/-�02���� '�2�02����/4 � ������� a-0���� �4�2-� 0������ 3��������0���������0 ����<������ �,���8�j�� ����f�� %0��� ���� '�� ���g�7���� �==<�� �� ;� /��2�� �;� 1��3� 4�3�3�� 2-�308� � -��� �#� 3 � )��0���2���030������2��3�*� 3��������=��� � � � � � � � � � � � � � microsoft word 9 bangladesh agron. j. 2017, 20(2): 81-86 performance performance performance performance of of of of system of rice intensificationsystem of rice intensificationsystem of rice intensificationsystem of rice intensification with with with with conventional method of rice cultivationconventional method of rice cultivationconventional method of rice cultivationconventional method of rice cultivation a. p. mondol, p. k. biswasa. p. mondol, p. k. biswasa. p. mondol, p. k. biswasa. p. mondol, p. k. biswas**** and m. s. islamand m. s. islamand m. s. islamand m. s. islam department of agronomy, sher-e-bangla agricultural university, dhaka1207 *corresponding author, e-mail: parimalbiswas@hotmail.com (received:received:received:received: 20 june 2017, accepted: accepted: accepted: accepted: 23 august 2017) key words: key words: key words: key words: sri, conventional method, boro season, rice varieties abstractabstractabstractabstract a field experiment was conducted in sher-e-bangla agricultural university research field of bangladesh during december 2012 to may 2013. this experiment was tested for two planting method consisting cm planting method (p1) and system of rice intensification (sri) planting method (p2) against five rice (oryza sativa) varieties named br 16 (v1), brri dhan29 (v2), brri dhan50 (v3), brri hybrid dhan2 (v4) and heera 4 (v5). the experiment was laid out in split-plot design with three replications. all yield parameters showed the highest for sri with higher effective tillers hill-1 (41.13), longer panicle (28.15 cm), higher total grains panicle-1 (216.89), number of filled grains panicle-1 (166.82) as a result 10.17and 12.5% higher grain yield and straw yield, respectively were observed in sri than the conventional method. introductionintroductionintroductionintroduction most of the asian countries accept rice as their staple food. asian countries cover near about 75% of the world’s rice supply (cabangon et al., 2002). sri is a rice cultivation method developed in madagascar which increase rice productivity with reducing the external inputs like fertilizers and herbicides (thakur et al., 2009 and vermeule, 2009). sustainable rice production would be possible by increasing yields on the same piece of land reducing the input like water, chemicals, fertilizers and labor (bouman et al., 2005; mati and nyamai, 2009). sri consists of some principles including transplanting of younger seedlings (< 15 days) at wider spacing in square grid pattern, only one seedling hill-1, water management with alternate wetting and drying, mechanical weeding and use of organic compost fertilizer instead of chemical fertilizer (stoop et al., 2002). use of younger seedlings, wider spacing and a single seedling hill-1 facilitate the utilization of the resource to develop stronger individual plants in the rice field.younger seedling in transplantation provide a longer vegetative growth period and single seedling reduce the competition and help to minimize the shading effect of lower leaves, as such lower leaves remain photosynthetically active for longer time and root activity remain higher for longer period as the supply of oxygen and carbohydrate to the root is increased (horie et al., 2005). supply of cytokinin to the lower leaves increase due to higher root activity, delay the senescence and help to maintain photosynthetic efficiency at the letter stage that result higher yield compared to cm (san-oh et al., 2006). but as awd is practiced in sri, it enhanced the supply of oxygen to the root zone that reducing the arenchyma and causing stronger, healthier root system to maximize the nutrient uptake (stoop et al., 2002). besides, the number of productive tiller is higher in sri (217%) over the cm (krishna et al., 2008). as such, the experiment was conducted to find out the proper method of sowing of rice in sri and compare to conventional method 82 mondol et al. materials materials materials materials aaaand methodsnd methodsnd methodsnd methods this experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka-1207 with three inbreed rice varieties viz., br16, brri dhan29, brri dhan50 and two hybrid var. brri hybrid dhan4 and heera4 in two planting system(sri and cm). the experiment was accomplished in a split-plot design with three replications. a 34 day old seedlings were transplanted maintaining spacing 25 cm × 15 cm in cm with two seedlings hill-1, where for sri, 16 day old seedlings with one seedlings hill-1. the unit plot size was 5m × 2.4m maintaining 30 cm × 30 cm spacing. two hand weddings were done for conventional plots, first at 16 days after transplanting followed by second at 15 days after first weeding. in sri plots, two hand rakings were done after hair line crack developed in the plots. in sri plots, alternate wetting and drying (awd) was practiced and in conventional plots continues flood irrigation was applied as per need of plants. the 46 % n containing urea was top-dressed in three equal installments at the rate of 260 kg ha-1 and 266 kg ha-1 for inbreed and hybrid, respectively. the first one after seedling recovery, second at vegetation stage and another at 7 days before panicle initiation. triple super phosphate (tsp), muriate of potash (mop), gypsum and zinc sulphate, (100, 120, 110 and 10 kg ha-1 ) for the inbreed varieties and 125, 120, 110, 15 kg ha-1 for the hybrid was applied as basal. all other intercultural operations were done as and when necessary. plants were infested with rice stem borer (scirphophaga incertolus) and leaf hopper (nephotettix nigropictus) to some extent which were successfully controlled by applying diazinone @ 10 ml/10 liter of water for 5 decimal lands and by furadan 5 g at the rate of 10 kg/ha. the grains were cleaned and sun dried to a moisture content of 14%. straw was also sun dried properly. the collected data were analyzed by using mstat-c package and the mean differences were adjusted by lsd test. results results results results aaaand discussionnd discussionnd discussionnd discussion number of effective and ineffective tillers hillnumber of effective and ineffective tillers hillnumber of effective and ineffective tillers hillnumber of effective and ineffective tillers hill----1111 the highest number of effective tillers hill-1 was produced in the planting method of sri than the conventional method (table 1) which was 250.04% higher than conventional method. among the variety, highest no. of effective tiller/plant was obtained from br16 (v1 ). in interaction showed that the variety br16 with sri gave highest tillers / plant than th other treatment. krishna et al. (2008) was also found 217% higher number of effective tillers in sri than cm. these might be due to use of tinny seedlings, wider spacing and efficient use of nutrients from the soil as the root system was well developed in sri. thakur et al. (2011) reported 38.5% increases in root length of sri over cm. wider spacing offered less interplant completion for resources. on the other hand, in sri seedlings are transplanted at two leaves stage (at third phyllochron), first tillering start at the fourth phyllochron (katayama,1951) that covers 40% of total tillering and get a chance of profuse tillering. as in cm transplanting is done after third phyllochron lead to a bigger loss in total tillers. ginigaddara and ranamukhaarachchi (2011) also supported that younger seedlings had ability to produce higher number of tillers hill-1 than older one. number of ineffective tillers hill-1 was higher in sri than the cm. this might be due to higher number of tertiary tillers in sri and most of the tertiary tillers inactive for production. 83 performance of system of rice intensification with conventional method panicle lengthpanicle lengthpanicle lengthpanicle length sri produced significantly longer panicle (28.15 cm) than the cm (25.77 cm). panicle was 9.25% longer in sri than the conventional system (table 1). the v2 produced the longest panicle in sri (30.53 cm) that was followed by v5 (29.12 cm) in sri while v3 (23.52 cm) produced the shortest panicle in cm (table 1). among the interactions, p2v2 produced the longest panicle but all the five varieties produced longer panicle in sri than cm. biswas et al. (2013); thakur et al. (2011) and latif et al. (2005) also revealed the similar findings of higher panicle length in sri. longer panicle of sri might be due to higher dry matter accumulation in the plant, higher photosynthetic rate and better utilization of the nutrients. integration of limited irrigation and mechanical weeding in sri, increase the aeration by dissolving oxygen from the irrigation water enhancing the root: shoot ratio (uphoff and randriamiharisoa, 2002). total number of grains panicletotal number of grains panicletotal number of grains panicletotal number of grains panicle----1111 the higher number of grains panicle-1 was produced in the planting method of sri (216.89) than the cm (172.58). which was 25.67% higher in sri (table 1). each of the five varieties, v1, v2, v3, v4 and v5 produced 17.19, 25.63, 37.31, 22.24 and 26.25% higher grains panicle-1 in sri than cm (table 1). thakur et al. (2011) also agreed that sri produced higher number of total grains panicle-1 than standard management practice. bozorgi et al. (2011) suggested that wider spacing gave maximum number of grains panicle-1. filled grains paniclefilled grains paniclefilled grains paniclefilled grains panicle----1111 sri (166.82) produced significantly higher number of filled grains panicle-1 than the cm (124.41) (table 1) which was 34.09% higher in sri than the cm. maximum number of filled grains panicle-1 were produced by v5 (186.37) that was statistically similar with v2 (166.80), v3 (172.23) and v4 (182.97) in sri planting system followed by v2 (157.70) and v5 (133.77) in cm and minimum number of grains panicle-1 by v3 (92.37) in cm. these result reveled that sri produced higher filled grains panicle-1 than cm in respect of variety. higher number of filled grins panice-1 in sri might be due to maximum utilization of solar radiation, availability of nutrients on the root zone and better uptake of nutrients by the developed root system and long lasting lower leaves of each of the hill as photosynthetically active. ali et al. (2013) observed higher number of filled grain panicle-1 from 15 day old seedling with intermittent irrigation, which was two important principle of sri, than 30 day old seedling with continuous flooded plot. thakur et al. (2011) also obtained the similar result of filled grain panicle-1 in sri. weight of 1000weight of 1000weight of 1000weight of 1000--- grainsgrainsgrainsgrains the higher weight of 1000-grains (25.60 g) was obtained from cm and lower (24.13 g) from sri (table 1). the v5 produced maximum 1000grains weight in cm that was followed by v5 (29.24 g) in sri and v4 (28.64 g) in cm. minimum 1000grains weight was recorded for v3 (19.83 g) in cm that was statistically similar with v2 (20.67 g) and v3 (19.69 g) in sri (table 1). mannan et al. (2009) also opined that heavier grain weight was found in early planted crop and grain weight decreased with the delayed transplanting. grain yieldgrain yieldgrain yieldgrain yield sri produced significantly higher (10.17%) yield (9.10 t ha-1) than cm (8.26 t ha-1) (table 1). the v1, v2, v3, v4 and v5 produced 14.29, 8.31, 8.57, 10.22 and 9.70% higher grain yield in sri than the cm with the respective varieties (table 1). in sri, plant received longer growth duration as it was transplanted in very tiny stage whereas in cm transplanted in old aged with shorter time. due to longer vegetative growth, tiller production was higher in sri than cm that 84 mondol et al. ultimately leads to lower yield in cm. on the other hand, number of effective tillers hill-1, panicle length, number of total grains panicle-1, number of filled grains panicle-1 was higher in sri than cm which might be the reason of higher yield in sri. ginigaddara and ranamukhaarachchi (2011) assured that the transplanting with younger seedlings in water saving rice production system produced more effective tillers hill-1, filled grains plant-1, panicle length compared to cm. suganthi et al. (2003) suggested that delayed transplanting significantly reduced the number of productive tiller which reduced the grain yield. better yielding performance of sri might be due to higher net photosynthetic rate of the fully expanded leaves at mid-tillering and improved utilization of photosynthates in the grain-filling stage (song et al., 2013). krishna et al. (2008) also observed that sri produced 15.65% higher grain yield over traditional method. straw yieldstraw yieldstraw yieldstraw yield higher straw yield was produced in the planting method of sri (9.48 tha-1) than conventional method (8.85 tha-1) (table 1). the 12.19% higher straw yield was produced in sri than conventional method. among the interaction, v4 (10.02 t ha -1) produced maximum straw yield in sri that was statistically similar for v2 in sri (9.80 t ha -1) and cm (9.53 t ha-1) followed by v5 (9.36 t ha -1) in sri. the minimum straw yield was produced in cm by v3 (8.38 t ha -1) which was statistically similar for v1 (8.64 t ha -1), v4 (8.83 t ha -1) and v5 (8.85 t ha -1) in cm. the higher straw yield might be due to higher amount of biomass production in extended vegetative growth period than the late transplanting in cm (mannan et al., 2009). das (2003) found 39 and 12% higher straw yield in sri compared to the field practice. table 1. effect of planting method on yield contributing character of inbred and hybrid rice treatments effective tillers (no. hill-1) ineffective tillers (no. hill-1) panicle length (cm) total grains panicle-1 (no.) filled grains panicle-1 (no.) unfilled grains panicle1 (no.) 1000grains weight (g) grain yield (t ha-1) straw yield (t ha-1) p1 11.75b 4.33b 25.77b 172.58b 124.41b 48.17 25.60a 8.26b 8.85b p2 41.13a 11.60a 28.15a 216.89a 166.82a 50.07 24.13b 9.10a 9.48a lsd (0.05) 2.267 5.359 0.4 15.98 9.751 ns 0.889 0.619 0.25 v1 33.43a 6.67b 26.38 b 163.60c 123.30c 40.25b 25.97b 8.10d 8.87c v2 27.77c 4.17b 29.05a 229.40a 162.25a 67.10a 21.42c 8.64abc 9.67a v3 30.13b 6.00b 25.24c 173.00bc 132.30bc 40.70b 19.76d 8.52bc 8.75c v4 22.57d 7.83b 25.94bc 189.20b 150.17ab 39.05b 27.25b 9.16a 9.42ab v5 18.30e 15.17a 28.20a 218.60a 160.07a 58.48a 29.91a 8.97ab 9.11bc lsd (0.05) 2.169 4.897 0.8783 18.99 18.546 11.794 1.303 0.41 0.4596 p1v1 14.40e 3.67cd 25.72e 150.60ef 120.87d 29.73c 26.77c 7.56f 8.64ef p1v2 11.67ef 0.67d 27.57c 203.30c 157.70bc 45.60b 22.16d 8.30de 9.53abc p1v3 14.33e 8.00bc 23.52f 145.80f 92.37e 53.47b 19.83e 8.17e 8.38f p1v4 9.47f 3.67cd 24.77e 170.10ef 117.37de 52.73b 28.64b 8.71cde 8.83def p1v5 8.87f 5.67bcd 27.27c 193.10d 133.77cd 59.30b 30.58a 8.56cde 8.85def p2v1 52.47a 9.67bc 27.04c 176.50d 125.73d 50.77b 25.17c 8.64cde 9.10cde p2v2 43.87b 7.67bc 30.53a 255.40a 166.80ab 88.60a 20.67e 8.99bc 9.80ab p2v3 45.93b 4.00cd 26.96d 200.20c 172.23ab 27.93c 19.69e 8.87bcd 9.12cde p2v4 35.67c 12.00b 27.11c 208.30b 182.97ab 25.37c 25.86c 9.60a 10.02a p2v5 27.73d 24.67a 29.12b 244.00 a 186.37a 57.67b 29.24b 9.39ab 9.36bcd lsd (0.05) 3.067 6.925 1.242 26.85 26.228 16.679 1.861 0.58 0.65 p1 = conventional method, p2 = sri, v1 = br 16, v2 = brri dhan29, v3 = brri dhan50, v4 = brri hybrid dhan2, and v5 = heera 4 85 performance of system of rice intensification with conventional method conclusionconclusionconclusionconclusion the present study showed that rice cultivation adopting sri (single seedling hill-1 and wide spacing) produced 10.17 % higher yield over the conventional method. moreover, in sri technique as very tiny seedlings was used that could be maintained easily in dapog seedbed and ready for transplanting in short time where it require 20 to 25 more in conventional method. besides, awd in sri was a water saving method with higher benefit. acknowledgementacknowledgementacknowledgementacknowledgement the authors are very thankful to bangladesh academy of science (bas) for providing the financial support to complete the research work. referencesreferencesreferencesreferences ali, m. s., m. a. hasan, s. sikder, m. r. islam and m. h. r. hafiz, 2013. effect of seedling age and water management on the performance of boro rice (oryza sativa l.) variety. the agriculturists. 11(2): 28-37. biswas, p. k., tohiduzzaman and t. s. roy, 2013. screening of rice varieties responsive to system of rice intensification (sri) in boro season. bangladesh agron. j. 16(1): 51-60. bouman, b. a., s. peng, a. r. castañeda and r. m. visperas, 2005. yield and water use of irrigated tropical aerobic rice systems. agric. water mngt. 74: 87-105. bozorgi, h. r., a. faraji, r. k. danesh, a. keshavarz, e. azarpour and f. tarighi, 2011. effect of plant density on yield and yield components of rice. world appl. sci. j. 12 (11): 20532057. cabangon, r. j., t. p. tuong and n. b. abdullah, 2002. comparing water input and water productivity of transplanted and direct-seeded rice production systems. agric. water mngt. 57: 11-31. das, l. 2003. varification and refinement of the system of rice intensification in selected areas of bangladesh. trial monitoring report. saef development group. ginigaddara s. g. a. and s. l. ranamukhaarachchi, 2011. study of age of seedlings at transplanting on growth dynamics and yield of rice under alternating flooding and suspension of irrigation of water management. recent res. sci. technol. 3(3): 76-88. horie, t., t. shiraiwa, k. homma, k. katsura, y. maeda and h. yoshida, 2005. can yields of lowland rice resume the increases that they showed in the 1980s? plant production science. 8: 251-272. katayama, t. 1951. ine mugi no bungetsu kenkyu (studies on tillering in rice, wheat and barley). yokendo publishing, tokyo, japan. krishna, a., n. k., biradarpatil, k. manjappa and b. b. channappagoudar, 2008. evaluation of system of rice intensification cultivation, seedling age and spacing on seed yield and quality in samba masuhri (bpt-5204) rice. karnataka j. agri. sci. 21(1): 20-25. latif, m. a., m. r. islama, m. y. alia and m. a. salequeb, 2005. validation of the system of rice intensification (sri) in bangladesh. field crops res. 93 (2-3): 281-292. 86 mondol et al. mannan, m. a., m. s. u. bhuiya, s. m. a. hossain and m. i. m. akhand, 2009. study on phenology and yielding ability of basmati fine rice genotypes as influenced by planting date in aman season. bangladesh j. agril. res. 34(3): 373-384. mati, b. m. and m. nyamai, 2009. promoting the system of rice intensification in kenya: growing more with less water: an information brochure used for training on sri in mwea. http://www.imawesa.net/publications/training manuals/imawesa training manual5-sri notes. san-oh, y., t. sugiyama, d. yoshhita, t. ookawa and t. hirasawa, 2006. the effect of planting pattern on the rate of photosynthesis and related process during ripening in rice plants. field crops res. 96: 113-124. song, c., z. xi, w. dangying, x. chunmei and z. xifu, 2013. influence of the improved system of rice intensification (sri) on rice yield, yield components and tillering characteristics under different rice establishment methods. plant prod. sci. 16(2): 191-198. stoop, w. a., n. uphoff, a. kassam, 2002. a review of agricultural research issue raised by the system of rice intensification (sri) from madagascar: opportunities for improving system for resource poor farmers. agric syst. 71: 249-274. suganthi, m., p. subbian, and s. marimuthu, 2003. optimization of time of planting and nitrogen levels to hybrid rice (adtrh. madras agric. j. 90(4-6): 339340. thakur, a. k., n. uphoff, and e. antony, 2009. an assessment of physiological effects of system or rice intensification (sri) practices compared with recommended rice cultivation practices in india. expl agric. 46: 77–98. thakur, a. k., s. rath, d. u. patil and a. kumar, 2011. effects on rice plant morphology and physiology of water and associated management practices of the system of rice intensification and their implications for crop performance. paddy water env. 9: 13–24. uphoff, n. and r. randriamiharisoa, 2002. reducing water use in irrigated rice production with the madagascar system of rice intensification (sri). in: bouman et al. (eds.). water-wise rice production (pp. 71-87). los baños: international rice research institute (irri). vermeule, m. 2009. more from less, from less to more. scaling up: dissemination of a rice cultivation technique. farming matters. amsterfoort, the netherlands p.3. bangladesh agron. j. 2014, 17(1): 1-10 amelioration of salinity stress on transplant aman rice through green manure and gypsum m. z. siam, s. s. hossain, a. k. hassan and m. a. kader department of agronomy, bangladesh agricultural university, mymensingh 2202, bangladesh corresponding author: abdul.kader@bau.edu.bd key words: salinity, aman rice, green manure, gypsum abstract an experiment was conducted at the net house of department of agronomy, bangladesh agricultural university, mymensingh from july to december 2012 to investigate the ameliorative effect of green manure and gypsum application on the yield of transplant aman rice variety brri dhan40 under various levels salinity stress. sodium chloride induced salinity was imposed at tillering stage of plant development. the levels of salinity were 0, 25 and 50 mm nacl. green manure @ 0, 5 and 10 t ha -1 and gypsum @ 0 and 1 g kg-1 soil were applied to ameliorate the salinity stress effect. 1 g kg-1 soil were applied to ameliorate the salinity stress effect. results revealed that the different levels of salinity had significant adverse effect on plant height, number of tillers hill-1, number of effective tillers hill-1, number of ineffective tillers hill-1, panicle length, number of grains penicle-1, 1000-grain weight, grain yield, biological yield and harvest index (hi). all the plants were affected badly when they were exposed to salinity level of 50 mm nacl. application of green manure and gypsum helped them ameiorate salinity either individually or in combination at all salinity levels. grain yield reduction at 50 mm salinity level was 38.64% compared to control which was minimized to 19.04% by the application of green manure @ 10 t ha -1. grain yield reduction was also minimized from 37.08% to 27% at the same level of salinity by the application of gypsum@ 1 g kg-1soil. similar amelioration effect was also observed in case of straw yield. the amelioration was improved further when both green manure and gypsum were applied. without any salinity stress grain yield was 4.49 t ha-1, which was reduced to 2.61 t ha-1 (41.87% reduction) when the crop was stressed with 50 mm salinity. application of green manure @ 10 t ha-1 and gypsum @ 1 g kg-1 soil improved grain yield to 4.00 t ha-1, where yield reduction was just 10.91%. similar improvement was also found in straw yield. the results of the study conclude that salinity stress in transplant aman rice var. brri dhan40 could successfully be ameliorated through application of green manure@ 10 t ha-1 and gypsum@ 1 g kg-1 soil. introduction one of the most common soil problems across the world is the salinity. however, out of 380 million hectare of saline soils on the earth surface, 240 million hectares are not strongly saline (massoud, 1994) and this area can be converted to potential areas for crop production. cultivation of these lands could improve the economic status of the small farmers in the belt of south and southeast asia. in bangladesh, over 30% of the net cultivable area lies in the coastal area being affected by varying degrees of soil salinity (karim et al., 1990). agricultural land use in these areas is very poor and cropping intensity is very low. salinity largely reduces the yield of rice in the coastal areas of bangladesh. the salinity of these soils is either derived from tidal flooding with saline water at high spring tides or from sporadic inundation with salt water during cyclonic storm surges. rice is a salt sensitive crop species. salinity level of 4dsm-1 is considered as critical level for rice. however, rice exhibits considerable intra-specific variability in tolerance to salinity (flowers and yeo, 1981). brri has been working for developing salt-tolerant rice variety for more than 30 years. for transplant aman season, they have developed brri dhan40 and released in 2003. this variety can tolerate 8-10 dsm-1 salinity when they are tender and 6 dsm-1 salinity in rest of the living period. salinity stress reduces the growth and yield of rice to a great extent (hossain, 2002; sen, 2002; islam 2 siam et al. et al., 2004; rashid, 2005). the permanent reclamation of the saline soils in bangladesh is difficult and complex due to frequent inundation and tidal flooding. it would, therefore, be wise to grow the salt tolerant varieties of rice. beside this, we need excellent inventories on salt-affected soils and development of cheaper options for amelioration of salinity. the amelioration of salinity stress basically involves replacing the sodium ions with more favorable calcium ions. application of organic manure and gypsum could be an effective way to ameliorate the salinity stress in rice to a great extent. use of green manures would pave a great path for reclamation of salinity. there is an intimate relationship between soil ph, level of co2 and calcium ion activity. it has been reported that the increasing amount of green manures in such soil facilitates rapid production of co2 and enhances the soluble calcium status of soils (vakeesan & nishanthan, 2007). that, in turn, replaces the sodium ions, resulting in the improvement of saline soil. gypsum is another source of ca2+. it replaces the na+ ion of soil. ameliorative effect of gypsum application is reported in saline soil as well as in sodic soil (khattak et al., 2007; singh et al., 2008; singh et al., 2009). to meet the consequent increasing demand of the growing population in the country food production needs to be increased either by enhancing arable land or by increasing yield per hectare. but the scope of enhancing arable land is very limited in bangladesh. so, food production must be increased by increasing yield per hectare to satisfy the consequent increased demand, particularly in the vulnerable areas of the country like salinity affected coastal area. considering above facts, the present research was conducted to find out the ameliorative effect of green manure and gypsum at various levels of salinity stress on transplant aman rice. materials and methods the research work was carried out at the nethouse of the department of agronomy, bangladesh agricultural university, mymensingh from july to december, 2012 using green manure @ 0, 5 and 10 t ha-1 and gypsum @ 0 and 1 g kg-1 soil to ameliorate salinity stress levels of 0, 25 and 50 mm nacl in transplant aman rice var. brri dhan40. the experiment was laid out in a completely randomized design (crd) with 3 (three) replications. the experimental soil was loamy in texture having a soil ph of 6.43, moderate in organic matter content. the soil was dried in sun and loosened and all the inert matter was removed. after that, the soil was filled in the chari having 60 cm diameter on top and 40 cm in height. each experimental chari contained five hills of rice and denotes a replication. seedlings were raised in well-prepared nursery bed. the applied fertilizer doses per chari were urea 5.1 g, tsp 1.68 g, mop 2.24 g 1, gypsum 2.24 g, and zinc sulphate (znso 4 ) 0.035 g. the total amount of tsp, mop, gypsum and zinc sulphate (znso4) and one third of urea was applied during the final chari preparation and the rest of urea was top dressed in two equal splits one at 20 days after transplanting (dat) and one at 40 dat. all the fertilizers were incorporated in the top most soil within 6 inch of the chari soil. 30-day old seedlings were transplanted. three seedlings were transplanted in each hill. gap filling (after 1 week of transplanting), regular weeding (hand weeding), regular irrigation and all other intercultural operations were practiced timely. salinity stress at the levels of 0, 25 and 50 mm nacl was imposed when the crop was at maximum tillering stage. gypsum was applied as per treatment specification immediately after salinity stress imposition. the common agricultural practices for growing brri dhan40 according to the recommendations of bangladesh rice research institute (brri) were followed. at maturity stage the crop was harvested treatment wise and data were collected on yield and yield parameters. the data were statistically analyzed according to gomez and gomez (1984). least significant difference (lsd) was used for mean comparisons. results and discussion the results revealed that the green manure and gypsum exerted significant influence on the yield and yield contributing characters of transplant aman rice var. brri dhan40 under various levels of salinity stress. 3 salinity stress on transplant aman rice effect of salinity stress the effect of salinity stress on yield and yield attributes of transplant aman rice var. brri dhan40 was statistically significant (table 1). it was observed that number of total tillers hill-1, effective tillers hill-1 and ineffective tillers hill-1decreased with the increasing salinity level. the highest no. of total tillers hill-1 (14.80), effective tillers hill-1 (11.14), and ineffective tillers hill-1 (3.66) were observed at the control (s0) salinity level. on the other hand, the lowest no. of total tillers hill-1 (13.09), no. of effective tillers hill-1 (10.36) and ineffective tillers hill-1 (2.76) were recorded at the 50 mm nacl (s2) salinity level. besides, panicle length, no. of grains panicle-1, grain yield and straw yield varied significant due to salinity stress. panicle length, no. of total spikelets panicle-1, no. of grains panicle-1, grain yield and straw yield decreased with the increasing salinity levels. the highest panicle length (24.31cm), no. of filled grains panicle -1 (118.1), 1000-grain weight (24.45 g), grain yield (4.88 t ha-1) and straw yield (6.37 t ha-1) were observed at the control (s0) salinity level and the lowest panicle length (23.51), no. of grains panicle-1 (74.00), 1000-grain weight (24.18 g), grain yield (3.22 t ha-1) and straw yield (4.14 t ha-1) were observed at the 50 mm nacl (s2) salinity level. the no. of sterile spikelets panicle-1 increased with the increasing salinity levels. the highest no. of sterile spikelets panicle-1 (28.81) was observed at the 50 mm nacl (s2) salinity level and the lowest no. of sterile spikelets panicle-1 (15.95) was observed at control (s 0) salinity level. so, the salinity stress @ 25mm & 50 mm nacl had significant negative impact on transplant aman rice. the similar result was previously reported by hossain (2002), sen (2002), islam et al. (2004) and rashid (2005). table 1. effect of salinity stress on yield and yield attributes of transplant aman rice var. brri dhan40 salinity stress no. of total tillers hill-1 no. of effective tillers hill-1 no. of non effective tillers hill-1 panicle length (cm) no. of grains panicle-1 no. of sterile spikelets panicle-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) s0 14.80 a 11.14 a 3.66 a 24.31 a 102.2 a 15.95 c 24.45 a 4.88 a 6.37 a s1 14.04 b 10.81 b 3.18 b 23.96 b 91.27 b 22.16 b 24.32ab 4.25 b 5.64 b s2 13.09 c 10.36 c 2.76 c 23.51 c 74.00 c 28.81 a 24.18 b 3.22 c 4.14 c f-test ** ** ** ** ** ** * ** ** lsd(0.05) 0.052 0.042 0.047 0.204 0.324 0.317 0.196 0.030 0.047 cv (%) 0.55 0.57 2.20 1.26 0.54 2.10 1.19 1.11 1.25 in a column, figures with same letter or without letter do not differ significantly, whereas figures with dissimilar letters differ significantly (as per dmrt) * = significant at 5% level of probability ** = significant at 1% level of probability ns = not significant s0 =0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl amelioration of salinity stress through green manuring green manuring exerted significant influence on yield and yield attributes of transplant aman rice var. brri dhan40 at different levels of salinity stress (table 2). the interaction effect of salinity levels and green manure application on number of total tillers hill-1, number of effective tillers hill-1, number of ineffective tillers hill-1 , number of total grain panicle-1, number of filled grain panicle-1, grain yield and straw yield were found statistically significant. the number of total tillers hill-1, effective tillers hill-1, ineffective tillers hill-1, number of total grain panicle-1, number of filled grain panicle-1, grain weight, straw yield, biological yield decreased with increasing salinity level and increased with increasing green manure level. the highest number of tillers (15.19), effective tillers hill-1 (11.35), number of ineffective tillers hill-1 (3.83), number of grain panicle-1 (121.2), number of grain panicle-1 (108.1), grain yield (5.24 t ha-1) and straw yield (6.70) were recorded at control salinity(s0)x 10 t ha 4 siam et al. 1green manure. the lowest number of tillers (12.80), number of effective tillers hill-1(10.15), ineffective tillers hill-1(2.65), number of grain panicle-1 (98.65), number of grain panicle-1 (66.78), grain yield (2.83 t ha-1) and straw yield (3.62) were observed in 50 mm salinity level x no green manure application. table 3 shows reduction of grain and straw yields of transplant aman rice var. brri dhan40 under various levels of salinity stress over control and under application of green manure. table 2. interaction effect of green manure and salinity stress on yield and yield attributes of transplant aman rice var. brri dhan40 interaction (m x s) total tillers hill-1 no. of effective tillers hill-1 no. of non effective tillers hill1 panicle length (cm) no. of grains panicle-1 no. of sterile spikelets panicle-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) m0s0 14.43 c 10.96 c 3.46 c 24.11 98.21 c 17.61 g 24.38 4.62 c 6.10 c m0s1 13.84 f 10.71 d 3.11 e 23.84 87.07 f 24.18 d 24.22 3.98 e 5.21 e m0s2 12.80 i 10.15 f 2.65 h 23.35 66.78 i 31.88 a 24.24 2.83 h 3.62 h m1s0 14.80 b 11.10 b 3.70 b 24.40 100.2 b 17.17 g 24.42 4.80 b 6.30 b m1s1 14.03 e 10.75 d 3.17 e 23.86 89.90 e 22.51 e 24.31 4.19 d 5.50 d m1s2 12.99 h 10.23 e 2.76 g 23.55 72.57 h 29.51 b 23.89 3.10 g 4.00 g m2s0 15.19 a 11.35 a 3.83 a 24.42 108.1 a 13.06 h 24.55 5.24 a 6.70 a m2s1 14.24 d 10.98 c 3.27 d 24.17 96.83 d 19.78 f 24.42 4.58 c 6.23 b m2s2 13.48 g 10.70 d 2.88 f 23.65 82.67 g 25.02 c 24.42 3.74 f 4.81 f f-test ** ** ** ns ** ** ns ** ** lsd(0.05) 0.090 0.074 0.082 0.561 0.550 0.052 0.083 cv (%) 0.55 0.57 2.20 1.26 0.54 2.10 1.19 1.11 1.25 in a column, figures with same letter or without letter do not differ significantly, whereas figures with dissimilar letters differ significantly (as per dmrt) * = significant at 5% level of probability ** = significant at 1% level of probability ns = not significant m0 = 0, m1 =5 ton green manure / ha , m2 =10 ton green manure / ha, s0 =0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl it is evident from the table that application of green manure @ 5 t ha-1 and 10 t ha-1 increased grain yield by 3.89% and 13.53% over control when no salinity was imposed. on the other hand, imposition of salinity stress @25 mm nacl and 50 mm nacl decreased grain yield by13.85% and 38.64%, respectively. over control, the grain yield reduction of 13.85% was minimized to less than 1% and that of 38.64% to 19.05% by applying green manure @ 10 t ha-1. in case of straw yield, application of green manure @ 5 t ha-1 and 10 t ha-1 increased straw yield by 3.27% and 9.74%, respectively over control when no salinity was imposed. on the other hand, imposition of salinity stress @25 mm nacl and 50 mm nacl decreased straw yield by 14.57% and 40.57%, respectively. over control the straw yield reduction of 14.57% was minimized to yield increase of 2.04% and that of 40.57% to 21.21% by applying green manure @ 10 t ha-1. the results revealed that the ameliorative effect of green manure at higher dose (10 t ha-1) was more effective than the lower dose (5 t ha-1) at the both salinity levels used in the study. table 3. amelioration of salinity stress on grain yield and straw yields of transplant aman rice var. brri dhan40 by green manuring interaction (m x s) grain yield (t ha-1) %increase or decrease over control straw yield (t ha-1) %increase or decrease over control m0s0 4.62 6.105 m1s0 4.8 3.89 6.305 3.27 5 salinity stress on transplant aman rice m2s0 5.24 13.52 6.7 9.74 m0s1 3.98 -13.85 5.215 -14.57 m1s1 4.19 -9.30 5.5 -9.90 m2s1 4.58 -0.75 6.23 2.04 m0s2 2.83 -38.63 3.628 -40.57 m1s2 3.10 -32.79 4.005 -34.39 m2s2 3.74 -19.04 4.81 -21.21 m0 = 0, m1 =5 ton green manure / ha , m2 =10 ton green manure / ha s0 = 0 mm nacl. s1 =25 mm nacl, s2 =50 mm nacl amelioration of salinity stress through gypsum application as evident in table 4, the effect of gypsum application was significant on yield and yield components of transplant aman rice var. brri dhan40 under different levels of salinity stress. the highest number of total tillers hill-1 (14.97), number of effective tillers hill-1 (11.21), number of ineffective tillers hill-1 (3.76), panicle length (24.42 cm), number of total spikelets-1 (119.1), number of grains panicle-1 (104.5), 1000-grain weight (24.49 g), grain yield (5.02 t ha-1) and straw yield (6.52 t ha-1) were recorded in no salinity stress condition and 1g gypsum kg-1 soil application. on the other hand, the lowest number of total tillers (12.85), effective tillers hill-1 (10.23), ineffective tillers hill-1 (2.68), panicle length (23.44 cm), number of total spikelets panicle-1 (100.7), number of grains panicle-1 (70.28), 1000grain weight (24.04 g), grain yield (2.99 t ha-1), straw yield (3.83 t ha-1) were obtained from 50 mm salinity level x no gypsum application. table 5 indicates reduction in grain and straw yields of transplant aman rice var. brri dhan40 under various levels of salinity stress over control and under application of gypsum. it is evident from the table 5 that application of gypsum @ 1 g kg-1 soil increased grain yield by 5.52% over control when no salinity was imposed. on the other hand, salinity stress @25 mm nacl and 50 mm nacl decreased grain yield by 13.66% and 37.08%, respectively. the grain yield reduction of 13.66% was curtailed to less than 7.56% and that of 37.08% to 27.26% over control by applying gypsum @ 1 g kg-1 soil. in case of straw yield, application of gypsum @ 1 g kg-1 soil augmented straw yield by 5.05% over control when there is no salinity. again, imposition of salinity stress @25 mm nacl and 50 mm nacl curtailed straw yield by 13.24% and 38.35%, respectively. over control the straw yield reduction of 13.24% was reduced to yield increase of 4.92% and that of 38.35% to 28.16% by applying gypsum @ 1 g kg-1 soil. the results revealed that the ameliorative effect of gypsum at higher dose (1 g kg-1 soil) was more effective than the control at the both salinity levels used in the study. table 4. interaction effect of gypsum and salinity stress on yield and yield attributes of transplant aman rice var. brri dhan40 interaction (g x s) total tillers hill-1 no. of effective tillers hill-1 no. of non effective tillers hill-1 panicle length (cm) no. of grains panicle-1 no. of sterile spikelets panicle-1 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) g0s0 14.64 b 11.07 b 3.57 b 24.20 99.87 b 17.28 e 24.41 4.75 b 6.21 b g0s1 13.93 d 10.72 d 3.15 c 23.94 89.17 d 23.20 c 24.27 4.107 d 5.39 d g0s2 12.85 f 10.23 f 2.68 e 23.44 70.28 f 30.37 a 24.04 2.99 f 3.83 f g1s0 14.97 a 11.21 a 3.76 a 24.42 104.5 a 14.61 f 24.49 5.02 a 6.52 a g1s1 14.15 c 10.90 c 3.21 c 23.98 93.36 c 21.12 d 24.37 4.39 c 5.90 c g1s2 13.33 e 10.49 e 2.84 d 23.58 77.73 e 27.24 b 24.32 3.46 e 4.46 e f-test ** ** * ns ** ** ns ** ** lsd(0.05) 0.074 0.060 0.067 0.458 0.449 0.042 0.067 cv (%) 0.55 0.57 2.20 1.26 0.54 2.10 1.19 1.11 1.25 6 siam et al. in a column, figures with same letter or without letter do not differ significantly, whereas figures with dissimilar letters differ significantly (as per dmrt) * = significant at 5% level of probability ** = significant at 1% level of probability ns = not significant g0 = 0 g gypsum / kg soil, g1 =1 g gypsum / kg soil s0 = 0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl table 5. amelioration of salinity stress on grain yield and straw yields of transplant aman rice var. brri dhan40 by gypsum application interaction (g x s) grain yield (t ha-1) %increase or decrease over control straw yield (t ha-1) %increase or decrease over control g0s0 4.75 6.21 g1s0 5.02 5.52 6.52 5.05 g0s1 4.10 -13.66 5.39 -13.24 g1s1 4.39 -7.56 5.90 -4.92 g0s2 2.99 -37.08 3.83 -38.35 g1s2 3.46 -27.26 4.46 -28.16 s0 = 0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl g0 = 0 g gypsum / kg soil, g1 =1 g gypsum / kg soil amelioration of salinity stress through green manuring and gypsum application interaction effect of gypsum and green manure was statistically significant on the yield and yield components of transplant aman rice under various levels of salinity stress (table 6). the highest number of tillers hill-1 (15.25), number of effective tillers hill-1 (11.40), number of ineffective tillers hill-1 (3.85), panicle length (24.53 cm), number of grain panicle-1 (122.5), grain yield (5.35 t ha-1) and straw yield (6.80 t ha-1) were recorded when there was no salinity stress in the crops with application of 1g gypsum kg-1 soil plus 10 t ha-1 green manure. in contrast, the lowest number of tillers (12.50), number of effective tillers hill-1(10.00), number of ineffective tillers hill-1 (2.50), panicle length (23.30 cm), number of grain panicle-1 (63.41), grain yield (2.61 t ha-1) and straw yield (3.30 t ha-1) were found at 50 mm salinity level with no gypsum application and no green manure application. table 7 showed the reduction in grain and straw yields of transplant aman rice var. brri dhan40 under various levels of salinity stress over control and under application of green manure. it perceived from the table that combined application of 5 t ha-1 green manure and 1 g gypsum kg-1 soil ,and combined application of 10 t ha-1 green manure and 1 g gypsum kg-1 soil increased grain yield by 10.46% and 19.15% over control when no salinity was imposed. on the other hand, salinity stress @25 mm nacl and 50 mm nacl decreased grain yield by 14.03% and 41.87%, respectively. over control, the grain yield reduction of 14.03% was turned into an increase yield of 4% and that of 41.87% to 10.91% by combined application of green manure @ 10 t ha-1 and gypsum @ 1 g kg-1 soil. in case of straw yield, combined application of 5 t ha-1 green manure and 1 g gypsum kg-1 soil and combined application of 10 t ha-1 green manure and 1 g gypsum kg-1 soil increased straw yield by 9.62% and 14.86% over control when there is no salinity imposed. again, imposition of salinity stress @25 mm nacl and 50 mm nacl decreased straw yield by 14.52% and 44.13%, respectively. the straw yield reduction of 14.52% was turned into an increase yield of 7.60% and that of 44.13% to 15.37% by combined application of green manure @ 10 t ha-1 and gypsum @ 1 g kg-1 soil. the results revealed that the ameliorative effect of combined application of 10 t ha-1 green manure and 1 g gypsum kg-1 soil was more effective than the combined application of 5 t ha-1 green manure and 1 g gypsum kg-1 soil at the both salinity levels used in the study. table 6. interaction effect of green manure, gypsum and salinity stress on yield and yield attributes of transplant aman rice var. brri dhan40 7 salinity stress on transplant aman rice interaction (m x g x s) total tillers hill-1 no. of effective tillers hill-1 no. of non effective tillers hill-1 panicle length (cm) no. of grains panicle-1 no. of sterile spikelets panicle-1 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) m0g0s0 14.20 10.90 3.30 c 24.00 96.60 f 19.21 i 24.32 abc 4.49 fg 5.92 f m0g0s1 13.70 10.60 3.10 d 23.80 85.52 k 25.13 f 24.20 bcd 3.86 j 5.06 h m0g0s2 12.50 10.00 2.50 g 23.30 63.41 p 33.08 a 23.70 d 2.61 o 3.30 m m0g1s0 14.65 11.02 3.63 b 24.22 99.82 d 16.01 j 24.43 abc 4.75 d 6.29 c m0g1s1 13.97 10.80 3.12 d 23.89 88.61 i 23.24 g 24.24abcd 4.10 h 5.37 g m0g1s2 13.10 10.30 2.80 ef 23.40 70.14 n 30.68 c 24.78 a 3.06 m 3.95 k m1g0s0 14.60 11.00 3.60 b 24.29 97.31 f 18.52 i 24.40 abc 4.64 e 6.12 d m1g0s1 13.88 10.60 3.10 d 23.93 86.50 j 23.40 g 24.20 bcd 3.96 i 5.02 h m1g0s2 12.80 10.10 2.70 f 23.49 68.81 o 32.03 b 23.77 d 2.89 n 3.58 l m1g1s0 15.00 11.20 3.80 a 24.50 103.1 c 15.83 j 24.43 abc 4.96 c 6.49 b m1g1s1 14.17 10.90 3.24 c 23.80 93.30 h 21.63 h 24.42 abc 4.42 g 5.98 ef m1g1s2 13.19 10.36 2.83 e 23.60 76.33 m 27.00 d 24.01 cd 3.32 l 4.43 j m2g0s0 15.12 11.30 3.82 a 24.30 105.7 b 14.11 k 24.50 abc 5.14 b 6.60 b m2g0s1 14.20 10.95 3.25 c 24.10 95.49 g 21.07 h 24.40 abc 4.50 f 6.09 de m2g0s2 13.26 10.60 2.86 e 23.54 78.61 l 26.01 e 24.65 ab 3.48 k 4.61 i m2g1s0 15.25 11.40 3.85 a 24.53 110.5 a 12.00 l 24.60 ab 5.35 a 6.80 a m2g1s1 14.29 11.00 3.29 c 24.24 98.18 e 18.50 i 24.45 abc 4.67 e 6.37 c m2g1s2 13.70 10.80 2.90 e 23.75 86.72 j 24.04 g 24.18 bcd 4.00 i 5.01 h f-test ns ns * ns ** ** ** ** ** lsd(0.05) 0.117 0.794 0.778 0.480 0.074 0.117 cv (%) 0.55 0.57 2.20 1.26 0.54 2.10 1.19 1.11 1.25 in a column, figures with same letter or without letter do not differ significantly, whereas figures with dissimilar letters differ significantly (as per dmrt) * = significant at 5% level of probability ** = significant at 1% level of probability ns = not significant m0 = 0, m1 =5 ton green manure / ha, m2 =10 ton green manure / ha, g0 =0 g gypsum / kg soil, g1 =1 g gypsum / kg soil, s0 =0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl table 7. amelioration of salinity stress on grain yield and straw yield by interaction of gypsum application and green manuring interaction (m x g x s) grain yield (t ha-1) % increase or decrease over control straw yield (t ha-1) % increase or decrease over control m0g0s0 4.49 5.92 m0g1s0 4.75 5.79 6.29 6.25 m1g0s0 4.64 3.34 6.12 3.37 m1g1s0 4.96 10.46 6.49 9.62 m2g0s0 5.14 14.47 6.6 11.48 m2g1s0 5.35 19.15 6.8 14.86 m0g0s1 3.86 -14.03 5.06 -14.52 m0g1s1 4.1 -8.68 5.37 -9.29 m1g0s1 3.96 -11.80 5.02 -15.20 m1g1s1 4.42 -1.55 5.98 1.01 m2g0s1 4.5 0.22 6.09 2.87 m2g1s1 4.67 4.00 6.37 7.60 m0g0s2 2.61 -41.87 3.307 -44.13 m0g1s2 3.06 -31.84 3.95 -33.27 m1g0s2 2.89 -35.63 3.58 -39.52 m1g1s2 3.32 -26.05 4.43 -25.16 m2g0s2 3.48 -22.49 4.61 -22.12 8 siam et al. m2g1s2 4 -10.91 5.01 -15.37 m0 = 0, m1 =5 ton green manure / ha , m2 =10 ton green manure / ha g0 = 0 g gypsum / kg soil, g1 =1 g gypsum / kg soil s0 = 0 mm nacl, s1 =25 mm nacl, s2 =50 mm nacl conclusion the results of the study reveal that combined application of green manure @ 10 t ha-1 and gypsum @ 1 g kg-1 soil ameliorated salinity stress in transplant aman rice remarkably. the combination of application of green manure @ 10 t ha-1 and gypsum @ 1 g kg-1 soil increased the grain yield by 4% in case of 25 mm nacl compared to control while grain yield decreased by 14.03% when no green manure and gypsum were applied. the combination also minimized the grain yield reduction from 41.87% to 10.91% in case of 50 mm nacl salinity stress. to validate the result, however, similar experiment needs to be conducted under natural occurrence of salinity stress. references flowers, t. j. and a. r. yeo. 1981. ion relations of plants under drought and salinity. aust. j. plant physiol. 13: 75-91. gomez, k a. and, a. a. gomez. 1984. statistical procedures for agricultural research. 2nd edn. john wiley and sons, new york. p.680. hossain, m. a. 2002. effect of salinity stress in some genotypes of rice. m. s thesis dept. crop bot., bangladesh agril. univ., mymensingh. hossain, m. m. 2006. effect of salinity level on growth and yield of advanced mutant rice in boro season. m. s. thesis, dept. crop bot., bangladesh agril. univ. mymensingh. islam, m. s., a. h. molla and h. a. quayum. 2004. effect of different levels of salinity on grain filling in rice. bull. inst. trop. agric., kyushu univ. 24: 19-22. karim, z., s. g. hussain and, m. ahmed. 1990. salinity problems and crop intensification in the coastal regions of bangladesh. bangladesh agricultural. research council (barc). p.1. khattak, s. g., a.izhar, m. j. khattak and naveedullah. 2007. effect of various levels of gypsum application on the reclamation of salt affected soil. pakistan. j. sarhad agric. 23 (3): 675-680. massoud, f. i. 1994. salinity and alkalinity as soil degradation hazards, fao/undp expert consolation on soil degradation, june 10-14, 1974, fao, rome. p.21. rashid, m. m. 2005. effect of salinity at different growth stages of transplanted aman rice mutants. m. s thesis, dept. crop rot., bangladesh agril. univ., mymensingh. sen, a. k. 2002. salinity tolerance studies of some transplanted aman rice cultivars. m. s thesis. dept. crop bot., bangladesh agril. univ., mymensingh. singh, y. p., r. singh and, d. k. sharma. 2009. combined effect of reduced dose of gypsum and salt tolerant varieties of rice (oryza sativa). indian j. agron. 54(1): 24-28. singh,y. p., r. singh and n. kumar. 2008. response of rice (oryza sativa) to gypsum rates in sodic soils. indian j. agric. res. 78(4): 362-365. vakeesan, s. and t. nishanthan. 2007. effect of green manuring (sesbania aculeata )and gypsum in submerged calcareous and noncalcareous soils. biol.fert. soil. 4(3): 159-162. 9 salinity stress on transplant aman rice 10 siam et al. microsoft word 9. baj-295_revised bangladesh agron. j. 2018, 21(1): 83-88 effect of fertilizer packages on broadcast aus rice in lentil-b. aus-blackgram cropping pattern in the char land of pabna in bangladesh m. maniruzzaman1*, m. r. alam1, m.s. islam1, m.z. islam1, m.s.h. molla2 and m.a. islam3 1on-farm research division, bangladesh agricultural research institute, pabna 2 on-farm research division, bangladesh agricultural research institute, rangpur 3 on-farm research division, bangladesh agricultural research institute, shampur, rajshahi *corresponding author, e-mail: maniruzzaman.bari@yahoo.com (received: 21 december 2017, accepted: 5 february 2018) keywords: yield, mixed cropping, gross return, total variable cost and gross margin abstract the experiment was conducted at char sadipur in the char land of pabna during aus rice seasons of 2014 and 2015 to determine appropriate fertilizer dose for enhancing yield of b. aus rice var. hashikalmi and also to increase farmers’ income in char land under high ganges river floodplain (aez-11). the experiment was laid out in a randomized complete block design with four dispersed replications. eight fertilizer packages t1: n40p9k16s6zn1(stb), t2: n50p9k16s6zn1, t3: n50p11k16s6zn1, t4: n50p9k20s6zn1, t5: n40p11k20s6zn1, t6: n50p11k20s6zn1, t7: n30p7k12s4.5zn0.75 kg ha-1 and t8: native nutrients (control) were tested for b. aus rice in lentil-b. ausblackgram cropping pattern. the treatment n50p11k20s6zn1 (t6) produced maximum grain yield 2.60 t ha-1 and 2.81 t ha-1of b. aus rice in 2014 and 2015 cropping season, respectively. the highest gross return (tk. 61,810 ha-1 in 2014 and tk. 72,250 ha-1 in 2015 cropping season) and gross margin (tk. 12,214 ha-1 in 2014 and tk. 21,550 ha-1 in 2015 cropping season) was also recorded from n50p11k20s6zn1 (t6) and lowest from control in both the years. introduction bangladesh is the fourth largest producer and consumer of rice in the world. rice is the primary staple food and the most important crop. rice is extensively grown in bangladesh which covers 75% of the total cropped area and about 60% labor is engaged in rice production. it was estimated 34.8 million metric tons in the year 2014 among all cereals in bangladesh (bbs, 2015). rice alone contributes around 10% to the gdp and 95% to the total food grain production (ber, 2010).it contains a number of energy rich compounds such as carbohydrates, fat, protein and reasonable amount of vitamins (nadeem et al., 2010). the national mean yield (2.60 t ha-1) of rice in bangladesh is lower than the potential national yield (5.40 t ha-1) and world average yield (3.70 t ha-1) (pingali et al., 1997). the lower yield of rice has been attributed to several reasons. most of the soils in bangladesh are deficient in n, p, k, s and zn for rice cultivation. moreover, soil fertility is declining further due to intensive cropping and imbalanced use of fertilizers by the farmers (biswas et al., 2001). as a result, growth and yield of rice is also declining in many cases. balance fertilization is, therefore, usually needed. in bangladesh, the lands of char area are not suitable for growing many crops and all seasons for low water holding capacity of the soils. in pabna, there is a vast area of char land under aez-11. nutrient status of char land is poor due to coarse textured soils, low water holding capacity, low nutrient content, river bank erosion and flooding. farmers of char land in pabna generally grow b. aus rice where they use local variety with no or limited fertilizers. for this 84 maniruzzaman et al. reason, the yield of b. aus rice in this region is much below than that of potential yield level. balanced fertilization can play a major role to enhance the present yield level. experimental evidences reveal that the crop is highly responsive to different fertilizers and its yield can be increased remarkably through judicious fertilization (mohamed, 1984; roy and singh, 1986; kazi et al., 2002). fertilizer recommendation solely based on crop response data often fails to show economic viability. in this context, perrin et al. (1979) reported that response of yield should be supported by economic evaluation for judicious fertilizer recommendation. since the application of balance fertilizer is important for increasing the yield of b. aus rice and very limited information in this regard is available for char areas, the present study was undertaken to determine the optimum fertilizer dose for maximizing b. aus rice yield in the char land areas of pabna. materials and methods the experiment was conducted at the char land of char sadipur areas of pabna in bangladesh during the aus rice seasons of 2014 and 2015. the experimental site was under gopalpur soil series of the high ganges river floodplain (aez-11). before starting the experiment, initial composite soil samples (0-15 cm depth) were collected from the experimental plots and were analyzed in the laboratory. the analytical result indicated that soil was sandy loam with very low organic matter content (0.80%) and slightly alkaline in nature. n content of soil was very low and p, s and zn content of the soil were low. k content of the soil was medium (table 1). the experiment was laid out in randomized complete block (rcb) design with three replications. the unit plot size was 5m ×x 4m. eight treatments consisted of t1: n40p9k16s6zn1 (stb), t2: n50p9k16s6zn1,t3: n50p11k16s6zn1, t4: n50p9k20s6zn1, t5: n40p11k20s6zn1, t6: n50p11k20s6zn1, t7: n30p7k12s4.5zn0.75 kg ha-1 and t8: native nutrients (control) were used in the experiment. the land was prepared by power tiller followed by laddering. after completion of land preparation the entire amount of p, k, s, zn and 1/3 n were applied as per treatment specification tsp, mp, gypsum, zinc sulphate and urea, respectively. table 1.nutrient status of the initial soil sample (0-15cm depth) of experimental plots at char sadipur, pabna soil properties values interpretation soil ph 8.1 slightly alkaline organic matter content (%) 0.80 very low total n (%) 0.05 very low available p (µg/g soil) 11.8 low available s (µg/g soil) 9.2 low available zn (µg/g soil) 0.57 low exchangeable k (meq %) 0.16 medium the seeds of b. aus rice were broadcasted in each plot on 3-5 may, 2014 & 2015 maintaining the seed rate of 50 kg ha-1 in both the seasons. the variety used for the trial was local hashikalmi. 50% n was applied as basal and the rest amount of n was top dressed in two splits at 25 and 45 day after sowing (das) in the form of urea. two times weeding were done at vegetative stage for better growth of the crops. other intercultural operations such as insect and disease management were done as and when necessary. the rice was harvested on 15-20 august, 2014 & 2015. necessary data on yield and yield components were collected at proper maturity of the crop. all the recorded data were statistically analyzed using a statistical package mstat program of computer and the means differences were adjudged by lsd test. cost and return analysis of different treatments were done. effect of fertilizer packages on broadcast aus rice 85 results and discussion plant height and yield contributing characters of b. aus rice have been presented in table 2. significant variation in respect of plant height, effective tiller hill-1, number of panicle m-2 and filled grains panicle-1 were observed due to different treatments. maximum plant height (122.4cm in 2015 and 96.7cm in 2014), effective tiller hill-1 (9.6 in 2015 and 5.73 in 2014), number of panicle m-2 (357.7 in 2015 and 267.67in 2014) and filled grains panicle-1(64.3 in 2015 and 55.32 in 2014) were recorded from n50p1k20s6zn1 (t6) and minimum plant height (112.3cm in 2015 and 85.57cm in 2014), effective tiller hill-1 (7.17 in 2015 and 4.1 in 2014), number of panicle m-2 (275.3 in 2015 and 197.33 in 2014) and filled grains panicle-1(37.53 in 2015 and 35.49 in 2014) were recorded from control (t8) treatment. in case of plant height similar finding was recorded by haque et. al. (2016) and li et. al. (1997), who stated that plant height increased significantly because of increasing fertilizer. the increase in plant height because of application of increased level of fertilizer might be associated with stimulating effect of fertilizer on various physiological processes. adequacy of optimum fertilizer probably favored the cellular activities during the development and grain formation which lead to increased number of effective tillers hill-1 and number of grains panicle-1. haque et. al. (2016) also reported that application of soil test best fertilizer showed better response on effective tillers production and number of grains. table 2. plant height and yield contributing parameters of b. aus at charsadipur, pabna during 2014 and 2015 cropping seasons treatments plant height (cm) effective tiller hill-1 no. of panicle (m-2) filled grains panicle-1 2014 2015 2014 2015 2014 2015 2014 2015 t1 88.63 117.0 5.20 7.86 228.33 312.0 41.43 56.17 t2 89.33 118.0 5.33 8.45 244.67 335.3 45.19 56.70 t3 91.57 117.4 5.63 8.86 244.67 341.3 43.54 57.77 t4 90.77 116.9 5.00 8.73 244.33 341.7 45.21 61.57 t5 90.13 119.8 5.67 8.69 260.33 343.7 49.89 58.27 t6 96.70 122.4 5.73 9.60 267.67 357.7 55.32 64.30 t7 87.00 115.1 4.30 7.70 232.00 298.0 38.63 50.70 t8 85.57 112.3 4.10 7.17 197.33 275.3 35.49 37.53 lsd (0.05) 5.331 3.21 0.75 0.83 16.55 25.13 6.68 10.17 cv(%) 2.44 1.56 9.36 5.68 2.84 4.41 8.61 7.55 note: t1: n40p9k16s6zn1 (stb); t2: n50p9k16s6zn1; t3: n50p11k16s6zn1; t4: n50p9k20s6zn1; t5: n40p11k20s6zn1; t6: n50p11k20s6zn1; t7: n30p7k12s4.5zn0.75 kg ha-1 ; t8: control thousand-seed weight, yield and percent yield increase over control of b. aus rice have been presented in table 3. the highest 1000 –grain weight (23.25g in 2015 and 23.8g in 2014) was observed from n50p11k20s6zn1 (t6) and the lowest 1000 -seeds weight (22.08g in 2015 and 22.77g in 2014) from control (t8) treatment. maximum straw yield of b. aus rice (5.65 t ha-1 in 2015 and 3.27 t ha-1 in 2014) was found from n50p11k20s6zn1 (t6) treatment which was statistically different from all other treatments and minimum straw yield (3.6 t ha-1 in 2015 and 1.73 t ha-1 in 2014) was control (t8). the highest seed yield (2.81 t ha-1 in 2015 and 2.6 t ha-1 in 2014) was attained from n50p11k20s6zn1 (t6) which was also statistically significant from all other treatments. on the contrary control (t8) treatment provided the lowest seed yield (1.55 t ha-1 in 2015 and 1.5 t ha-1 in 2014). the cumulative contribution of potential yield traits might be the reason for higher grain yield from n50p11k20s6zn1 (t6). in contrast, poor crop growth and yield traits resulted the lowest grain yield in control (t8). maximum yield increased (81% in 86 maniruzzaman et al. 2015 and 73% in 2014) over control was obtained from n50p11k20s6zn1 (t6).the overall results indicate that in char land conditions soils are dominated with sand particles and low organic matter which causes deficiency in nutrient availability in soil and make imbalance in subsequent plant uptake. therefore, 100% soil test based fertilizer package plus 25% additional nutrients specially n, p and k fertilizer dose n50p11k20s6zn1 (t6) enhance optimum plant growth and development and higher yield in b. aus rice. these results are supported by the findings of das et. al. (2003). he reported that increasing levels of npk application increased the yield attributing characters and nutrient uptake by the cereal crops, which ultimately increased the grain and straw yields. table 3. yield and 1000grain weight of b. aus at charsadipur, pabna during 2014 and 2015 cropping season treatments 1000grain weight (g) straw yield (t ha-1) grain yield (t ha-1) % yield increase over control (t8) 2014 2015 2014 2015 2014 2015 2014 2015 t1 22.97 22.25 2.17 4.08 1.70 2.00 13 29 t2 23.00 22.43 2.32 4.38 1.78 2.13 19 37 t3 23.00 22.67 2.50 4.66 1.89 2.37 26 53 t4 23.30 22.83 2.36 4.41 2.16 2.36 44 52 t5 23.37 23.08 2.65 5.02 2.26 2.67 51 72 t6 23.80 23.25 3.27 5.65 2.60 2.81 73 81 t7 23.03 22.25 2.13 4.01 1.59 1.76 6 14 t8 22.77 22.08 1.73 3.60 1.50 1.55 lsd (0.05) ns 0.54 0.473 0.61 0.254 0.39 cv% 1.52 1.38 8.12 7.81 5.38 10.30 note: t1: n40p9k16s6zn1 (stb); t2: n50p9k16s6zn1; t3: n50p11k16s6zn1; t4: n50p9k20s6zn1; t5: n40p11k20s6zn1; t6: n50p11k20s6zn1; t7: n30p7k12s4.5zn0.75 kg ha-1; t8: control cost and return cost and return analysis demonstrated that maximum gross margin (tk. 21550 ha-1in 2015 and tk. 12214 ha-1in 2014) was obtained from n50p11k20s6zn1 (t6) followed by t5 fertilizer package (table 4). probably higher production and gross return (tk. 72250 ha-1 in 2015 and tk. 61810 ha-1 in 2014) from this treatments resulted in higher economic return. negative gross margin was recorded from the treatments t8 (control) and t7 which might be due to lower yield and gross return is less than the total variable costs in both the years. table 4. cost and return analysis of b. aus rice as influenced by different fertilizer packages at char sadipur, pabna during 2014 and 2015 cropping season treatment gross return (tk. ha-1) total variable cost (tk.ha-1) gross margin (tk. ha-1) 2014 2015 2014 2015 2014 2015 t1: n40p9k16s6zn1 (stb) 40510 52240 48721 49770 -8211 2470 t2: n50p9k16s6zn1 42560 55740 49177 50278 -6617 5462 t3: n50p11k16s6zn1 45300 61380 49452 50553 -4152 10827 t4: n50p9k20s6zn1 50280 60430 49321 50422 959 10008 t5: n40p11k20s6zn1 53150 68460 49140 50190 4010 18270 t6: n50p11k20s6zn1 61810 72250 49596 50700 12214 21550 t7: n30p7k12s4.5zn0.75 38190 47230 47600 48450 -9410 -1220 t8: control 35190 41800 44250 44500 -9060 -2700 effect of fertilizer packages on broadcast aus rice 87 selling price: b. aus: grain = tk. 20.00 kg-1; straw= tk. 3.00 kg-1 conclusion based of this study, it can be concluded that fertilizer packages exerted significant effect on the growth and yield performance of b. aus rice at the char land of pabna. the treatment n50p11k20s6zn1 (t6) demonstrated better performance on yield and yield attributes of b. aus than the other treatments. the maximum economic return in terms of gross return and gross margin was also recorded with the same fertilizer packages. references bbs. 2015.yearbook of agricultural statistics of bangladesh. bangladesh bureau of statistics, statistics division, ministry of planning, government of people's republic of bangladesh, dhaka. pp.39 ber. 2010.bnagladesh economic review, department of finance, ministry of finance, govt. of the people’s republic of bangladesh, dhaka. biswas, j.c., m. t. ahmed and m.r. islam. 2001. lodging vs non-lodging in brri dhan 32. bangladesh j. train. dev.14(1-2): 107-113. das, k., d.n. medhi and b. guha. 2003. application of crop residues in combination with chemical fertilizers for sustainable productivity in rice (oryza sativa)-wheat (triticum aestivum) system. indian j. agron. 48 (1): 8-11. kazi, b. r., f. c. oad and a. lakho. 2002. effect of irrigation frequencies on growth and yield of soybean. pakistan j. appl. sci. 2(6): 661-662. mohamed, s. a. 1984. effect of irrigation water and fertilization on yield and water use efficiency of corn plants in fayoum governorate. moshtohor, egypt annual agril. sci. 20(2): 221-235. li, z., s. r. sarkat, k. s. nayak and i. ravi. 1997. physiological effect of nitrogen application on aromatic rice. j. south china agric. univ. 18(3): 13-17. haque1, m. z., m. s. a. fakir, j. c. biswas, s. s. zaman and m. h. rahman. 2016. effect of irrigation, fertilizer package and planting density on growth and yield of boro rice (var. brri dhan28). international j. of emerging trends in sci. and techn. 3(5): 3939-3946 nadeem a., a. iqbal, h. z. khan, m. k. hanif and m. u. bashir. 2010. effect of different sowing dates on the yield and yield components of direct seeded fine rice (oryza sativa l.) j. plant breeding and crop sci. 2(10): 312-315. pingali, p.l., m. hossain and r. v. gerpacio. 1997. the asian rice bowls: the returning crisis? cab international, london and irri, mcpo box 3217. makati 1271, philippines. perrin, r. k., d. l.winkelmen, e. r. moscardi and j. r. anderson. 1979. economic training manual. information bulletin no. 27. cimmyt, mexico. p. 5. roy, r. k. and k. s. p. singh. 1986. response of pop-corn (zea mays) to plant population and nitrogen. indian j. agron. 31(1): 87-92. bangladesh agron. j. 2019, 22 (1): 79-88 performance of rapeseed and mustard with different planting techniques p.k. biswas1*, l.j. ferdous2, t.s. roy1 and s.m. masum3 1 professor, dept. of agronomy, sher-e-bangla agricultural university 2 ms student, dept. of agronomy, sher-e-bangla agricultural university 3 assoc. professor, dept. of agronomy, sher-e-bangla agricultural university *corresponding e-mail: parimalbiswas@hotmail.com (received: 04 june 2019, accepted: 05 october 2019) keywords: planting technique, rapeseed, mustard, yield abstract the experiment was conducted at sher-e-bangla agricultural university farm to evaluate the performance of five rapeseed and mustard varieties under two different planting techniques. the planting techniques were as conventional sowing and sowing seeds in puddle soil that assigned to the main plot and five varieties viz. improved tori-7, bari sarisha -13, bari sarisha -15, bari sarisha -16 and sau sr-3 in the sub-plots. almost all the studied parameters were found statistically similar under two planting techniques except siliqua length that was higher (5.51 cm) in conventional method compared to that of sowing in puddled soil (5.14 cm). the highest number of siliquae plant-1 (143.67) was obtained from bari sarisha -16 that was similar to sau sr-03 (134.15) and improved tori-7 (116.90). the maximum1000-seed weight (4.35 g) was obtained from bari sarisha -16 under conventional planting method that was similar to bari sarisha -13 irrespective of planting methods. the maximum number of siliqua plant-1 (145.20) was found in bari sarisha 16 under conventional planting method that was similar to the same variety in puddle soil (142.13), sau sr-03 in both the planting method and improved tori-7 in conventional method (131.20). the improved tori-7 variety gave the maximum seed yield (2.24 t ha-1) followed by bari sarisha -16 (1.96 t ha-1). the highest seed yield was given by the variety bari sarisha -16 in conventional planting method (2.39 t ha-1) that was similar to improved tori-7 variety irrespective of planting techniques. introduction rapeseed & mustard (brassica spp. l.) commonly known as mustard in bangladesh, is a cool season, thermo sensitive as well as photosensitive crop (ghosh and chatterjee, 1988). rapeseed and mustard is the major oilseed crop of bangladesh both on the basis of its total cultivated area and production, respectively. the present yield of rapeseed-mustard (0.95 tha-1) is very low as compared to other oilseeds growing countries in the world. the main reasons of lower yield are lack of good quality seed and inadequate adoption of improved production technologies developed by different research institutes (miah et al., 2014). presently, on an average, 2.3 to 2.4 million tonnes of edible oils, both in oil and seeds form, are imported in the country (alam, 2018). the internal production of edible oil can meet up only less than one-third of the annual requirement (mondal and wahhab, 2001). there is a great scope of increasing yield of mustard by selecting high yielding varieties and improving management practices (bhuiyan et al., 2008). time of sowing is very important for rapeseed/ mustard production (rahman et al., 1988; mondal and islam, 1993 and mondal et al., 1999). sowing at proper time allows sufficient growth and development of about:blank 88 biswas et al. a crop to obtain a satisfactory yield which can be fitted in between aman and boro rice. farmers mostly grow the traditional variety of tori-7 for its shorter duration (70-80 days) but average yield only 750 kg ha-1. this variety is advantageous to grow as catch crop between aman and boro rice with minimum input and tillage practices. there is ample scope of replacing the traditional farmers varieties by the short duration yellow seeded variety, having yield capacity of 1.50-1.65 tha-1 and can easily be grown in the aman-mustard boro cropping system with 2-3% increased oil content for yellow seed without hampering existing boro rice cultivation. in such situation, sowing time of rapeseed and mustard should be done by late october to early november that is frequently affected by rainfall and make challenge of better productivity of the pattern. therefore, the proposed study was undertaken to find out the suitability of alternate planting method of rapeseed and mustard to fit it in the promising and widely used cropping pattern aman-mustard-boro of bangladesh. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka during the period from november 2013 to june 2014. the seeds of five rapeseed and mustard varieties namely improved tori-7, bari sarisha-13, bari sarisha-15, bari sarisha-16 and sau sr-3 were collected from bangladesh agricultural research institute (bari), joydebpur, gazipur and sher-e-bangla agricultural university (sau). the land was finally leveled with leveler to ensure uniform application of water. the unit plot size was 4m x 3m.the plot was fertilized with @ 250-170-85-150-5-15 kg ha-1 of urea, tsp, mop, gypsum, zinc sulphate and boric acid, respectively. the whole amount of all fertilizers except urea was applied as a basal dose during final land preparation. the urea fertilizer was applied as two equal installments; as basal dose and before flowering. the treatment of puddle condition of respective plots were maintained by applying water & finally leveled. the equal amount of seeds of all varieties were sown on november 5, 2013. the spacing was maintained as 30 cm in continuous soild line. the experiment was laid out in a split-plot design with three replications. two planting techniques namely conventional (p1) and puddle soil (p2) were assigned in the main plot and five varieties viz., improved tori-7 (v1), bari sarisha-13 (v2), bari sarisha-15 (v3), bari sarisha-16 (v4) and sau sr-3 (v5) in the sub-plot. water was ensured to the field in such a way that there should not have any scarcity of water that affects the experiment. two hand weedings were done for all the treatments at 15 and 25 days after sowing (das). the field was infested by different insects and diseases which were controlled as and when necessary. the different varieties were harvested on different dates at full maturity. the harvested plants were threshed & the seeds were dried to a constant moisture level. statistical analyses were done by using the crop stat computer package and the mean differences among the treatments were compared by least significant difference test at 5 % level of significance following gomez and gomez (1984). performance of rapeseed and mustard 87 results and discussion siliqua length effect of planting technique the siliqua length was significantly differed due to planting technique (table 1) where longer siliqua (5.51 cm) was found in conventional sowing compared to that of sowing in puddle soil (5.14 cm). effect of variety the variety showed significant effect on siliqua length (table 1). the maximum length (7.19 cm) was recorded in bari sarisha-13 followed by bari sarisha-15 (5.24 cm), improved tori-7 (4.94 cm) and sau sr-3 (4.83 cm) whereas the minimum siliqua length was found in bari sarisha-16 (4.42 cm) that was similar to sau sr-3 and improved tori-7.this result was in conformity to the finding of akhter (2005) who pointed out that variations in siliqua length among the varieties were statistically significant. hossain et al. (1996) also reported that the varieties differed significantly in respect of siliqua length. it has been also reported that the napus group showed higher siliqua length than that of juncea group (bari, 2001). interaction effect of planting technique and variety the maximum siliqua (7.41 cm) was obtained from conventional planting technique with the variety bari sarisha-13 (p1v2), which was statistically similar with the same variety sown in puddle soil (p2v2), and the smallest siliqua (4.29 cm) from bari sarisha-16 in puddle soil (p2v4) which was statistically similar with p1v4 (4.55 cm), p1v5 (4.85 cm), p2v3 (4.91 cm) and p2v5 (4.82 cm) (fig. 1). fig. 1. interaction effect of planting technique and variety on siliqua length of rapeseed and mustard p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 number of siliqua plant-1 effect of planting technique there was no significant variation of siliquae number plant-1 observed between the two planting technique though the numerically higher number of siliquaeplant-1 (118.11) was found in the conventional planting method and lower number of siliquaeplant-1 (109.53) was obtained from the puddle soil condition (table 1). 0 1 2 3 4 5 6 7 8 v1 v2 v3 v4 v5 si liq u a le n gt h ( cm ) variety p1 88 biswas et al. effect of variety the highest number of siliqua plant-1 (143.67) was observed in v4 which was statistically similar with v5 (134.15) and v1 (116.90) while the lowest number of siliqua (83.95) was obtained from v3 which was statistically similar with v2 (90.43). akhter (2005), roy (2008) and mamun et al. (2014) agreed with the result of this finding that the number of siliqua plant-1 of rapeseed mustard was significantly affected by the varieties. interaction effect of planting technique and variety the maximum number of siliqua plant-1 (145.20) was obtained from conventional planting technique of the variety bari sarisha-16 (p1v4), which was statistically similar with the same variety sown in puddle soil (p2v4), p1v5 (138.67), p1v1 (131.20) and p2v5 (129.63). the lowest number of siliqua plant -1 (80.43) was obtained from bari sarisha-15 in puddle soil (p2v3) which was statistically similar with p1v2 (88.00), p1v3 (87.47), p2v2 (92.87) and p2v1 (102.60) (fig. 2). number of seeds siliqua-1 effect of planting technique there was no significant variation of number of seeds siliqua-1 observed between the two planting technique though the numerically higher number of seeds siliqua1 (18.34) was found in the puddle soil condition and lower number of siliquae siliqua-1 (17.99) was obtained from the conventional planting method (table 1). table1. effect of planting technique and variety on siliqua length, no. of siliqua plant-1and no. of seeds siliqua-1 of rapeseed and mustard treatments siliqua length (cm) number of siliqua plant-1 number of seeds siliqua-1 planting technique: p1 p2 lsd(0.05) cv (%) variety: v1 v2 v3 v4 v5 lsd(0.05) cv (%) 5.51 5.14 0.142 1.70 4.94 7.19 5.24 4.42 4.83 0.529 8.13 118.11 109.53 ns 20.80 116.90 90.43 83.95 143.67 134.15 28.432 20.41 17.99 18.34 ns 9.56 15.55 21.32 22.34 12.95 18.67 2.993 13.46 p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 effect of variety the highest number of seeds siliqua-1 (22.34) was observed in bari sarisha-15 (table 1) which was statistically similar with bari sarisha-13 (21.32) and the lowest number of seeds siliqua-1(12.95) from bari sarisha-16 which was statistically similar with improved tori-7 variety(15.55).variation in seeds siliqua-1 among the varieties was in conformity with mamun et al. (2014), who found the highest seeds siliqua-1 in bari sarisha-13 and the lowest seeds siliqua-1 in bari sarisha-16 this result supports the findings of jahan and zakaria (1997) and gurjar and chauhan (1997). variation in seeds siliqua-1 among the varieties was also in conformity with islam et al. (1994) who found a significant variation in number of seeds siliqua-1 among different varieties of mustard and rapeseed. performance of rapeseed and mustard 87 fig. 2. interaction effect of planting technique and variety on siliqua number/plant of rapeseed and mustard p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 interaction effect of planting technique and variety the maximum number of seeds siliqua-1 (23.32) was obtained from conventional planting technique of the variety bari sarisha-15 (p1v3), which was statistically similar (22.75) with bari sarisha-13sown in puddle soil (p2v2), p2v3 (21.37), p1v2 (19.88) and p2v5 (19.40). the lowest number of seeds siliqua -1(12.30) was obtained from bari sarisha-16 in puddle soil (p2v4) which was statistically similar with p1v4 (13.60), p2v1 (15.91) and p1v1 (15.20) (fig. 3). figure 3. interaction effect of planting technique and variety on number of seeds/ siliquaof rapeseed and mustard p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 weight of 1000 seeds effect of planting technique there was no significant variation of 1000-seed weight observed between the two planting technique though numerically higher weight (3.79 g) was found in the conventional planting method and lower weight (3.45 g) from the puddle soil 0 20 40 60 80 100 120 140 160 v1 v2 v3 v4 v5 si liq u ae n o ./ p la n t variety p1 p2 0 5 10 15 20 25 v1 v2 v3 v4 v5 n o . o f se e d s/ si liq u a variety p1 p2 88 biswas et al. condition (table 2). this result was in conformity with the findings of hossain et al. (2013) who reported that 1000seed weight did not show any significant variation due to sowing method (table 2). effect of variety the maximum weight of 1000-seeds (4.07 g) was observed in bari sarisha-13 followed by bari sarisha-16 (table 2) which was followed by sau sr-3 (3.69 g) and improved tori-7 (3.07 g) and the lowest 1000-seed weight (3.21 g) from bari sarisha-15. mamun et al. (2014) also observed that bari sarisha-13 had the highest 1000seed weight (4.00 g) whereas the lowest (2.82 g) in sau sarisha-3. table 2. effect of planting technique and variety on 1000-seed weight and seed yield of rapeseed and mustard treatments weight of 1000 seeds (g) seed yield (t ha-1) planting technique: p1 p2 lsd(0.05) cv (%) variety: v1 v2 v3 v4 v5 lsd(0.05) cv (%) 3.79 3.45 ns 8.15 3.07 4.07 3.21 4.07 3.69 0.297 6.70 1.89 1.56 ns 13.88 2.24 1.57 1.34 1.96 1.53 0.195 9.24 p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 interaction effect of planting technique and variety the maximum 1000-seed weight (4.35 g) was obtained from conventional planting technique of the variety bari sarisha-16 (p1v4), which was statistically similar (4.09 g) with bari sarisha-13 sown in conventional method (p1v2) and puddle soil condition, p2v2 (4.05 g). the lowest1000-seed weight (2.87 g) was obtained from improved tori-7 in puddle soil (p2v1) which was statistically similar with p2v3 (3.04 g) (fig. 4). 0 1 2 3 4 5 v1 v2 v3 v4 v5 w t. o f 1 0 0 0 s e e d s (g ) variety p1 p2 performance of rapeseed and mustard 87 fig. 4. interaction effect of planting technique and variety on 1000-seed weight of rapeseed and mustard p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 seed yield effect of planting technique there was no significant variation of seed yield observed between the two planting technique though the numerically higher seed yield (1.89 tha-1) was found in the conventional planting method and the lower seed yield (1.56 t ha -1) from the puddle soil condition (table 2). this result was at par with the findings of sarkees (2013) who did not show any variation of mustard seed yield due to planting techniques. effect of variety higher seed yield (2.24 t ha-1) was observed in improved tori-7 variety (table 2) which was followed by bari sarisha-16 (1.96 t ha-1) and bari sarisha-13 (1.57 t ha-1). the lowest seed yield (1.34 t ha-1) was obtained from v3 (bari sarisha15) which was statistically similar with sau sr-3 (1.53 t ha-1). the result agreed with rahman (2002), bari (2001), zaman et al. (1991) and mendham et al. (1981) who reported that seed yield of rape and mustard were varied with different varieties. interaction effect of planting technique and variety the highest seed yield (2.39 t ha-1) was obtained from conventional planting technique of the variety bari sarisha-16 (p1v4), which was statistically similar with the variety improved tori-7 sown in puddle soil (p2v1) and same variety in conventional planting method of p1v1 (2.11 t ha -1). the lowest seed yield (1.11 t ha-1) was obtained from bari sarisha-15 in puddle soil (p2v3) which was statistically similar with p2v5 (1.38 t ha -1) (fig. 5). figure 5. interaction effect of planting technique and variety on seed yield of rapeseed and mustard p1 = conventional technique, p2 = puddle soil, v1 = improved tori-7, v2 = bari sarisha13, v3 = bari sarisha-15, v4 = bari sarisha-16, v5 = sau sr-3 conclusion 0 0.5 1 1.5 2 2.5 v1 v2 v3 v4 v5 se e d y ie ld ( t/ h a) variety p1 p2 88 biswas et al. the planting method did not show any significant variations in all the studied parameters except siliqua length. variety showed significant influence on all the studied parameters. the highest seed yield (2.39 t/ha) was obtained from conventional planting technique of the variety bari sarisha-16 and the lowest seed yield (1.11 t/ha) was obtained from bari sarisha-15 in puddle soil. based on the results of the study, it could be concluded that rapeseed and mustard can be cultivated in puddle soil without any yield loss. mustard var. bari sarisha-16 in conventional method and improved tori – 7 in both conventional and puddle soil condition showed higher yield performance compared to that of other varieties. acknowledgement the authors expressed their deepest cordiality to the ministry of science and technology, govt. of the people’s republic of bangladesh to provide them financial support to conduct the study. the authors also expressed their sincere appreciation and immense indebtedness to the agronomy department and relevant other personnel of sher-e-bangla agricultural university, dhaka-1207, for their sincere cooperation and cordial help to make the study a successful one. references akhter, s.m.m. 2005. effect of harvesting time on shattering, yield and oil content of rapeseed and mustard. m.s. thesis, sau, dhaka, bangladesh. alam, a.k.m.f. 2018. edible oil import grows. the financial express, august 19, 2018. bari. 2001. annual report of 2000-2001. oilseed research centre. bangladesh agricultural research institute. joydebpur, gazipur, bangladesh. bhuiyan m.s., m.r.i. mondol, m.a. rahaman, m.s. alam and a.h.m.a. faisal. 2008. yield and yield attributes of rapeseed as influenced by date of planting. int. j. sustain. crop prod. 3(3): 25-29. fao. 2003. production year book. food and agriculture organization of the united nations. rome 00100. italy. (57): 122. fao. 2011. food and agriculture organization. faostat database of agriculture (crops). ghosh, r.k. and b.n. chatterjee. 1988. effect of dates of sowing on oil content and fatty acid profiles of indian mustard. indian j. oilseed res. 5(2): 144-149. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. second edn. intl. rice res. inst., john wiley and sons. new york. pp.1-340. gurjar, b.s. and d.v.s. chauhan. 1997. yield attributes and seed yield of indian mustand (brassica juncea) as influenced by varieties, fertility levels and spacing in harsi command area. indian j. agron. 42(1): 142-144. hossain, m.b., m.s. alam and m.a. ripon. 2013. effect of irrigation and sowing method on yield and yield attributes of mustard. rajshahi university j. life earth agric. sci. 41: 65-70. about:blank about:blank performance of rapeseed and mustard 87 hossain, m.f., a.k.m. zakaria and m.h. jahan. 1996. technical report on variety screening adaptive research oilseeds. rural development academy, bogra, bangladesh.pp.6-34. islam, n., m. choudhury and m.r. karim. 1994. effects on sowing date on growth and development of mustard and rapes. progress. agric. 59: 2329. jahan, m.h., and a.k.m. zakaria. 1997. growth and yield performance of different varieties of rapeseed, mustard and canola in level barind tract. progress agric. 8(1&2): 144-152. khan, m.j. r.a. khattak and m.a. khan. 2000. influence of sowing methods on the productivity of canola grown in saline field. pakistan j. biol. sci. 3(4): 687-691. mamun, f., m.h. ali, i.f. chowdhury, m. hasanuzzaman and m.a. matin. 2014. performance of rapeseed and mustard varieties grown under different planting density. sci. agri. 8(2): 70-75. miah, m.a.m., m.a. rashid and s.a.m. shiblee. 2014. assessment of socioeconomic impacts of oilseed research and development in bangladesh. final report submitted to the agricultural economics and rural sociology, barc, farmgate, dhaka. mendham, n.j., p.a. shipway and r.k. scott. 1981. the effect of delayed sowing and weather on growth, development and yield of winter oilseed rape (brassica napus). j. agric. sci. camb. 96: 389-416. mondal, m.r.i. and m.a. islam. 1993. effect of seed rate and date on yield and yield components of rapeseed. bangladesh j. agril. sci. 20(1): 29-33. mondal, m.r.i. and m.a. wahhab. 2001. production technology of oil crops. oilseed research center. bangladesh agril. res. inst. joydebpur, gazipur. pp.6-15. mondal, m.r.i., m. biswas, m.k. hydar-ali, and m.a. akbar. 1999. response of rapeseed genotype dhali to seed rate and seeding date. bangladesh j. agril. res. 24(1): 83-90. nigussie, a., t. adefris and t. zerihum. 1996. effect of agronomic practices on seed and oil yields of ethiopian mustard (brassica carinata a. braun) and rapeseed (brassica napus l.) trop. agric. 73(2): 94-99. rahman, m.m., m.u. salam, m.g. miah and m.s. islam. 1988. effect of sowing time on the performance of mustard (ss-75). bangladesh j. agric. res. 13(1): 47-51. rahman, m.m. 2002. status of oilseeds and future prospects in bangladesh. paper presented in review workshop on the impact of technology transfer on oil crops, held at bari on 29 april, 2002. roy, l.r. 2008. influence of weeding on growth and yield of rapeseed varieties. m.s. thesis, sau, dhaka, bangladesh. sarkees, n.a. 2013. response of growth, yield and oil of rapeseed to sowing method and seeding rate. iosr j. agric. sci. & v. sci. 3(1): 01-06. zaman, m.w., z. ali, h.m.a. awal and m.z.i. talukder. 1991. influence of different stages of harvesting on the yield, oil content and shattering loss in oleiferous brassica. bangladesh j. sci. ind. res. 29(4): 25-32. 88 biswas et al. microsoft word 4. baj-284_revised bangladesh agron. j. 2018, 21(1): 39-50 mitigation of salinity stress in soybean using organic amendments j. ferdous1*, m. a. mannan2, m. m. haque2, m. s. alam3 and s. talukder4 1bangladesh jute research institute, dhaka 2department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh 3department of soil science, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding author, e-mail: tanny.jannat92@gmail.com (received: 5 december 2017, accepted: 25 february 2018) keywords: salinity stress, biochar, organic amendments and mitigation abstract a pot experiment was carried out in semi-controlled condition at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur from november 2015 to march 2016 to assess the effect of organic amendments to mitigate salinity stress in soybean var. bari soybean 5. two types of organic amendments i) water hyacinth compost and ii) rice husk biochar were mixed in soil @ 5 and 10 t ha-1 of both. saline solution was prepared by adding tap water in seawater to make 5 and 10 ds m-1 salinity respectively. plants were irrigated with the salt solution from 14th day after sowing (das) to maturity and the control plants were irrigated with tap water. data on different parameters like plant height, leaf, stem, root dry matter and yield contributing parameters were recorded at harvest. experimental results revealed that salinity decreased plant height, dry weight of leaf, stem and root as well as yield of soybean plant-1. application of water hyacinth compost and rice husk biochar had positive effects on mitigating the negative effects of salinity stress on all those parameters studied. however, rice husk biochar at the rate of 5 t ha-1 showed best result to mitigate salinity stress at low salinity (5 dsmds m-1 condition. introduction soybean (glycine max. l) is one of the most important oilseeds crop of the world due to its high food value. it contains about 36-40% protein, 18-20% oil, 30% carbohydrate, 7.3% sugar and 9.3% dietary fiber and also unsaturated fatty acids, minerals like ca and p including vitamin a, b, c and vitamin d. in bangladesh, the total cultivated area under soybean cultivation is 41440 hectares which produces 65883 tons of oil per year (fao, 2013).the cultivation of soybean is increasing in bangladesh mostly due to its increasing demand in the poultry sector. agricultural productivity is severely affected by soil salinity and the damaging effect of salt accumulation in agricultural soils has become an important environmental concern all over the world. accumulation of excess na and cl in plant body causes ionic imbalances that may impair the selectivity of root membranes and induce potassium deficiency (gadallah, 1999). the deficiency of k initially leads to chlorosis and then causes necrosis (gopal and dube, 2003).excess soluble salts reduce yields by impairing germination, or creating osmotic gradients which interfere with the uptake of essential nutrients by plants (bernstein, 1975; stamatiadis et al., 1999; tanji, 1990). out of 2.86 million hectares of coastal and offshore lands, about 1.056 million hectares are affected by varying degrees of salinity (srdi, 2010). reclamation of saline soil is difficult. 40 ferdous et al. therefore, alternative ways may be adopted like mitigation of salinity using different organic amendments. there are evidences that soil amendments with various organic substances such as farmyard manure, poultry manure and mulch can be used for the reduction of toxic effects of salinity in various plant species (idrees et al., 2004; abou el-magd et al., 2008; leithy et al., 2010; raafat and thawrat, 2011). water hyacinth-compost is a dark, crumbly, earthy-smelling mixture that consists mostly of decayed organic matter. composts are widely used as sources of nutrients and organic matter. the beneficial influence of compost on soil physical and chemical properties has been well documented (debosz et al., 2002; lynch et al., 2005; tejada et al., 2006; wanas and omran, 2006). biochar is pyrolysed organic material intended for use as a soil amendment to sustainably sequester c and concurrently improve soil function, while avoiding any adverse effects, on both the short and long terms (verheijen et al., 2009). biochar enhanced soil water-holding capacity (asai et al., 2009; laird et al., 2010); improved soil water permeability (asai et al., 2009); improved saturated hydraulic conductivity (shc) (asai et al., 2009); reduced soil strength (chan et al., 2007, 2008) and modification in soil bulk density (ρb) (laird et al., 2010). therefore, both water hyacinth-compost and biochar may reduce the harmful effect of salinity on crop productivity. however, scarce information is available on the effect of the organic amendments on mitigation of salinity on soybean. therefore, this experiment was carried out to analyze the effect of water hyacinth-compost and biochar on growth performance of soybean under saline conditions. materials and methods the pot experiment was carried out in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur from november 2015 to march 2016 to investigate the effect of organic amendments to mitigate negative effects of salinity stress on different parameters of soybean var. bari soybean 5. the soil was a sandy loam with ph 6.93, total n =0.07%, available p= 0.08 mg 100 g-1 dry soil, exchangeable k = 0.79 cmolc kg-1 dry soil, available s = 10 ppm, organic carbon = 0.61%, cec = 13.05 cmolc kg-1 dry soil and ec = 0.4 ds m-1. the experiment was consisted of 15 treatments as: t0=control (without organic amendments and seawater ),), t1=5 dsm-1seawater, t2=10 ds m-1 seawater, t3 = compost @ 5 t ha-1,t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 5 dsm-1sea water, ds m-1 seawater, t6= compost @ 10 t ha-1 with 5 ds m-1 seawater, t7= compost @ 5 t ha-1 with10 dsm-1 sea water with 10 ds m-1 seawater,t8= compost @ 10 t ha-1 with10 dsm-1 seawater, with 10 ds m1 seawater, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1,t11= biochar @ 5 t ha-1 with 5 dsm-1seawater,ds m-1 seawater, t12= biochar @10 t ha-1 with 5 dsm-1seawater,ds m-1 seawater, t13= biochar @ 5 t ha-1 with10 dsm-1seawater,with 10 ds m-1 seawater, t14= biochar @ 10 t ha1 with10 dsm-1seawater.with 10 ds m-1 seawater. saline solution was prepared by adding tap water in seawater to make 5 and 100 mm salinity, respectively. plants were irrigated with 5 dsm-1ds m-1and 10 dsm-1ds m-1salt solution from 14 days after sowing (das) to maturity and control plants were irrigated with tap water. the organic amendments were mixed with pot soil. the experiment was laid out in a completely randomized design (crd) with three replications. data on different parameters like plant height, dry matter production in different plant parts, yield and yield contributing charecteristieswere recorded at harvest. the recorded data were statistically analyzed by “cropstat 7.2” software to examine the significant variations in the results due to different treatments. the treatment means were compared by least significance difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion plant height soil salinity caused a significant effect in plant height of soybean. at control, plant height was found 17.3 cm but it was 17.7 cm and 15.0 cm under 5and 10 dsm-1 salinity levels, respectively mitigation of salinity stress in soybean 41 (fig. 1). it was observed that plant height increased at 5 dsm-1 than control, because lower level of salinity might have acted as nutrient of plant growth. at 10 dsm-1 seawater treatment caused a drastic decreased in plant height and it indicates that high level of salinity was harmful for plant height. organic amendments significantly increased the plant height of soybean under both control and salt stress conditions. at control condition, highest plant height (23.0 cm) was found when soil was treated with biochar @10 t ha-1 and the lowest height (19.3 cm) with water hyacinth compost was added in the soil @10 t ha-1. at 5 dsm-1 salinity stress highest plant height (22.0 cm) was recorded when soil was treated with water hyacinth compost @ 10 t ha-1 and the lowest height (19.7 cm) when soil was treated with compost @ 5 t ha-1 but similar plant height also recorded from biochar amendment @ 10 t ha-1. on the other hand, under 10 dsm-1 salinity stress the tallest plant (20 cm) was found when soil was treated with biochar @ 10 t ha-1 and the shortest plant (16.7 cm) from compost amendment @ 5 t ha-1. results indicated that plant height decreased with increasing salinity level and varied with different organic amendments. fig. 1. effect of organic amendments on plant height of soybean under saline conditions. bars indicate se () t0=control (without organic amendments and sea water), t1= 5 dsm-1 mm seawater, t2= 10 dsm-1 sea water, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 5 dsm-1 sea water, t6= compost @ 10 t ha-1 with 5 dsm-1 seawater, t7= compost @ 5 t ha-1 with 10 dsm-1seawater, t8= compost @ 10 t ha-1 with 10 dsm-1 seawater, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 5 dsm-1 sea water, t12= biochar @10 t ha-1 with 5 dsm-1 seawater, t13= biochar @ 5 t ha-1 with 10 dsm-1 seawater, t14 = biochar @ 10 t ha-1 with 10 dsm-1 sea-water dry matter production in different plant parts leaf dry matter leaf dry matter weight plant-1 was reduced due to salinity (fig. 2). the lowest leaf dry mass (1.97 g plant-1) was recorded at 10 dsm-1salt condition. organic amendment significantly increased leaf dry matter of soybean under control and saline conditions. highest leaf dry matter (7.11 g plant-1) was observed when biochar was added @ 5 t ha-1 and it was 6.32g plant-1 when compost was added @ 10 t ha-1 under control condition. at 5 dsm-1 salinity condition, highest leaf dry matter (4.57 g plant-1) was obtained from compost @ 5 t ha-1 and lowest (3.9 g plant-1) at compost @ 10 t ha-1. at 10 dsm-1saline condition, highest leaf dry matter (2.69 g plant-1) was obtained when soil was treated with biochar @ 10 t ha-1 and it was lowest (2.43 g plant-1) when compost added @ 10 t ha-1. dry weight of stem, leaves and whole plant showed approximately decrease with salinity observed by hussein et al. (2007). 0.0 5.0 10.0 15.0 20.0 25.0 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 pl an t h ei gh t ( cm ) treatments 42 ferdous et al. fig. 2. effect of organic amendments on leaf dry weight of soybean under saline conditions. bars indicate se (). t0=control(without organic amendments and sea water), t1= 50 mm sea water t2= 100 mm sea water, t3 = compost @ 5 t/ha, t4= compost @ 10 t/ha, t5= compost @ 5 t/ha with 50mm sea water, t6= compost @ 10 t/ha with 50mm sea water, t7= compost @ 5 t/ha with 100mm sea water, t8= compost @ 10 t/ha with 100mm sea water, t9= biochar @ 5 t/ha, t10= biochar @ 10 t/ha, t11= biochar @ 5 t/ha with 50mm sea water, t12= biochar @10 t/ha with 50mm sea water, t13= biochar @ 5 t/ha with 100mm sea water, t14= biochar @ 10 t/ha with 100mm sea water stem dry matter stem dry matter plant-1 of soybean was reduced due to salinity and reduction was higher with increasing salinity levels (fig. 3). the lowest stem dry mass (2.02 g plant-1) was recorded at 100 mm salt condition. at every case of compost and biochar treatment the stem dry mass was increasing compared to normal condition. highest stem dry matter (6.18 g plant-1) was observed when biochar was added @ 5 t ha-1 and the lowest value (5.40 g plant-1) when compost was added 5 t ha-1 under control condition. at 5 dsm-1salinity condition, highest stem dry matter (4.70 g plant-1) was obtained from biochar @ 5 t ha-1 and the lowest stem dry matter (4.21 g plant-1) at 5 t ha-1. under 10 dsm-1 saline condition highest stem dry matter (2.69 g plant-1) was obtained when soil was treated with compost @ 5 t ha-1 and lowest (2.28 g plant-1) when biochar was added 10 t ha-1. reduction in stem dry matter due to salinity as compared to control was reported earlier by karim et al. (1992) in triticale. 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 le af d ry w ei gh t ( g) treatments mitigation of salinity stress in soybean 43 fig. 3. effect of organic amendments on stem dry weight of soybean under saline conditions. bars indicate se (). t0=control (without organic amendments and sea water), t1= 50 mm sea water t2= 100 mm sea water, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 50mm sea water, t6= compost @ 10 t ha-1 with 50mm sea water, t7= compost @ 5 t ha-1 with 100mm sea water, t8= compost @ 10 t ha-1 with 100mm sea water, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 50mm sea water, t12= biochar @10 t ha-1 with 50mm sea water, t13= biochar @ 5 t ha-1 with 100mm sea water, t14 = biochar @ 10 t ha-1 with 100mm sea water root dry matter experimental results revealed that root dry matter was significantly affected by salinity (fig. 4). the lowest root dry mass (0.50 g plant-1) was recorded at 10 dsm-1 salt condition. under control condition, highest root dry matter (2.53 g plant-1) was recorded with adding biochar @ 5 t ha-1 and the lowest (2.17 g plant-1) with @ 10 t ha-1. at 5 dsm-1 salinity condition, highest root dry matter (1.70 g plant-1) was obtained with biochar @ 5 t ha-1 and lowest (1.37 g plant-1) with compost @ 5 t ha-1. at 10 dsm-1 saline condition, highest root dry matter (0.90 g plant-1) was obtained when soil was treated with compost @ 5 t ha-1 and lowest (0.77 g plant-1) with biochar as well as compost both @ 10 t ha-1. salinity induced root mass reduction was reported earlier by raptan et al. (2001) and sultana et al. (2007) in mungbean. 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 st em d ry w ei gh t (g /p la nt ) treatments 44 ferdous et al. fig. 4. effect of organic amendments on root dry weight of soybean under saline conditions. bars indicate se (). t0=control (without organic amendments and sea water), t1= 50 mm sea water t2= 100 mm sea water, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 50mm sea water, t6= compost @ 10 t ha-1 with 50mm sea water, t7= compost @ 5 t ha-1 with 100mm sea water, t8= compost @ 10 t ha-1 with 100mm sea water, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 50mm sea water, t12= biochar @10 t ha-1 with 50mm sea water, t13= biochar @ 5 t ha-1 with 100mm sea water, t14 = biochar @ 10 t ha-1 with 100mm sea water shoot dry matter the shoot dry weight is defined as the sum total of leaf, stem, and petiole dry weight. shoot dry matter was negatively affected by increasing salinity level (fig. 5). the lowest shoot dry mass (3.99 g plant-1) was recorded at 10 dsm-1 salt condition. organic amendment significantly increased shoot dry matter of soybean under control and saline conditions. highest shoot dry matter (13.30 g plant-1) was recorded when biochar was added @ 5 /ha-1 and it was 11.71 g plant-1 when biochar was added @ 10 t ha-1 under control condition. at 5 dsm-1salinity condition highest shoot dry matter (8.93 g plant-1) was obtained adding biochar @ 5 t ha-1 and lowest (8.08 g plant-1) adding compost @ 10 t ha-1. under 10 dsm-1 saline condition, highest shoot dry matter (5.26 g plant-1) was recorded with compost @ 5 t ha-1 and the lowest (4.97 g plant-1) with biochar as well as compost both @ 10 t ha-1.reduction in shoot dry weight due to salinity as compared to control was reported by sultana et al. (2007) in six mungbean varieties. increasing salinity level resulted in significant reductions of shoot biomass, root length and volume. at each salinity level, incorporation of biochar increased shoot biomass, root length and volume observed by akhtar et al. (2015). 0.00 0.50 1.00 1.50 2.00 2.50 3.00 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 ro ot d ry w ei gh t (g /p la nt ) treatments mitigation of salinity stress in soybean 45 fig. 5. effect of organic amendments on shoot dry weight of soybean under saline conditions. bars indicate se (). t0=control (without organic amendments and sea water), t1= 50 mm sea water t2= 100 mm sea water, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 50mm sea water, t6= compost @ 10 t ha-1 with 50mm sea water, t7= compost @ 5 t ha-1 with 100mm sea water, t8= compost @ 10 t ha-1 with 100mm sea water, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 50mm sea water, t12= biochar @10 t ha-1 with 50mm sea water, t13= biochar @ 5 t ha-1 with 100mm sea water, t14 = biochar @ 10 t ha-1 with 100mm sea water total dry matter reduction in total dry matter production under saline condition and the positive effect of organic amendment on total dry matter production are presented in fig. 6. both 5 dsm-1and 10 dsm-1 salinity affect significantly on the total dry matter production in soybean plant. total dry matter of plant was decreased with the increase of soil salinity and the highest (4.36 g plant-1) reduction occurred at 10 dsm-1 salinity level. organic amendment significantly increased total dry matter of soybean under control and saline conditions. highest total dry matter (15.66 g plant-1) was recorded with adding biochar @5 t ha-1 and the lowest (13.94 g plant-1) with biochar @10 t ha-1 under control condition. at 5 ds m-1 mm salinity condition, highest total dry matter (10.53 g plant-1) was obtained from biochar @ 5 t ha-1 and the lowest (9.72 g plant-1) from compost @ 10 t ha-1. under 10 dsm-1 saline condition, highest total dry matter (6.16 g plant-1) was obtained when soil was treated with compost @ 5 t ha-1 and lowest (5.46 g plant-1) when biochar was added in the soil @ 5 t ha-1. reduction in total dry matter production under salinity was also reported raptan et al. (2001) in mungbean. 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 sh oo t d ry w ei gh t ( g/ pl an t) treatments 46 ferdous et al. fig. 6. effect of organic amendments on total dry matter weight of soybean under saline conditions. bars indicate se (). t0=control (without organic amendments and sea water), t1= 50 mm sea water t2= 100 mm sea water, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 50mm sea water, t6= compost @ 10 t ha-1 with 50mm sea water, t7= compost @ 5 t ha-1 with 100mm sea water, t8= compost @ 10 t ha-1 with 100mm sea water, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 50mm sea water, t12= biochar @10 t ha-1 with 50mm sea water, t13= biochar @ 5 t ha-1 with 100mm sea water, t14 = biochar @ 10 t ha-1 with 100mm sea water yield and yield contributing characters number of pods plant-1 soybean plants exposed to salinity caused a significant reduction in number of pod plant-1 (table 1). organic amendments with water hyacinth compost and rice husk biochar increased pods plant-1 at 50 mm and 100 mm salinity stress. the lowest number of pod plant-1 was found at 10 dsm-1salinity level (16). but due to organic amendment, the number of pod plant-1 was increased as compare to the control. highest number of pods plant-1 (51) was observed when biochar was added @ 5 t ha-1 and the lowest (33.67) @ 10 t ha-1 under control condition. at 5 dsm-1 salinity condition, highest number of pods plant-1 (35.33) was obtained from biochar @ 5 t ha-1 and lowest (27.67) by applying compost @ 5 t ha-1. under 10 dsm-1salinity condition, highest number of podplant-1 (22.67) was obtained when soil was treated with compost @ 5 t ha1 and the lowest (20.33) was recorded when biochar as well as compost added @ 10 t ha-1. similar result was found by leithy et al. (2010) on peanut at different levels of salinity. number of seed pod-1 the number of seed pod-1 also reduced by salinity stress in soybean (table 1). this reduction rate was increasing with the increasing salinity stress. application of compost and biochar (5 and 10 t ha-1) significantly increased the number of seeds pod-1 in soybean at 0, 5 and 10 dsm-1 salinity level. the lowest number of seeds pod-1 (0.8) was observed at 10 dsm-1 salinity level. but due to addition of organic amendment, the number of seeds pod-1 was increased compared to control. the highest number of seeds pod-1(2.17) was observed when biochar was added @5 t ha-1 and the lowest (1.84) when compost added @ 10 t ha-1. at 5 dsm-1salinity condition, highest number of seeds pod-1(1.80) was obtained from biochar @5 t ha-1 and lowest (1.27) at @ 10 t ha-1. under 10 dsm-1saline condition, highest number of seed pod-1(1.31) was obtained when soil was treated with biochar @ 5 t ha-1 and it was lowest (1.05) when compost was added 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 t0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 to ta l d ry w ei gh t ( g/ pl an t) treatments mitigation of salinity stress in soybean 47 in the soil @ 10 t ha-1. similar result was also found by leithy et al. (2010) on peanut at different levels of salinity. 100-seed weight salt stress caused a significant decrease in 100seed weight of soybean plant (table1). organic amendments with both compost and biochar significantly increased the 100-seed weight of soybean at 0, 5 and 10 dsm-1 salinity stress conditions. highest 100-seed weight (14.9 g) was observed when biochar was added @ 5 t ha-1 and the lowest 100-seed weight (13.86 g) when compost was added @ 5t ha-1under control condition. at 5 dsm-10 mm salinity condition, highest 100-seed weight (12.40 g) was obtained from biochar @ 5 t ha-1 and lowest 100-seed weight (11.20 g) when compost was applied @ 5t ha-1. under 10 dsm-1 saline condition, highest 100seed weight (11.2) was obtained when soil was treated with compost @ 5 t ha-1and it was lowest (9.67) when biochar was added in the soil @ 5t ha-1. seed yield salt stress caused a significant decrease in yield of soybean plant (table1). organic amendments with both compost and biochar significantly increased the yield of soybean at 0, 50 and 100 mm salinity stress conditions. under 5 dsm-1 salinity stress, both compost and biochar also showed a considerable yield in soybean plant. table 1. effect of organic amendments on yield and yield contributing characters of soybean under saline condition treatments no. of pods plant-1 no. of seeds pod-1 100seed weight (g) seed yield (g plant-1) t0 33.33 1.43 13.10 6.18 t1 25.00 1.17 10.40 2.94 t2 16.00 0.80 8.90 1.16 t3 37.00 1.96 13.90 11.42 t4 33.67 1.84 14.30 9.41 t5 27.67 1.40 11.20 4.79 t6 32.00 1.27 12.20 4.87 t7 22.67 1.17 11.20 2.95 t8 20.33 1.05 10.40 2.19 t9 51.00 2.17 14.90 15.65 t10 46.00 2.02 14.50 13.33 t11 35.33 1.80 12.40 8.63 t12 32.33 1.71 12.10 7.54 t13 21.67 1.31 9.70 2.74 t14 20.33 1.17 10.30 2.61 lsd (0.05) 3.92 0.20 0.68 2.15 cv (%) 7.80 8.20 3.40 20.10 t0=control (without organic amendments and sea water), t1= 5 dsm-1 seawater t2= 10 dsm-1 seawater, t3 = compost @ 5 t ha-1, t4= compost @ 10 t ha-1, t5= compost @ 5 t ha-1 with 5 dsm-1seawater, t6= compost @ 10 t ha-1 with 5 dsm-1seawater, t7= compost @ 5 t ha-1 with 10 dsm-1 seawater, t8= compost @ 10 t ha-1 with 10 dsm-1seawater, t9= biochar @ 5 t ha-1, t10= biochar @ 10 t ha-1, t11= biochar @ 5 t ha-1 with 5 dsm-1 seawater, t12= biochar @10 t ha-1 with 5 dsm-1seawater, t13= biochar @ 5 t ha-1 with 10 dsm-1seawater, t14= biochar @ 10 t ha-1 with 10 dsm-1 seawater at 5 dsm-1 salinity stress yield was higher at 10 t ha-1 than 5 t ha-1compost treatments but at 10 dsm-1 salt level the increment of yield occurred at 5 t ha-1compost treatment. in case of biochar, at 0, 5 and 10 dsm-1 salt condition yield was higher at 5 t ha-1 than 10 t ha-1. highest seed yield (15.65 g plant-1) was observed when biochar was added @ 5 t ha-1and the lowest (9.41 g plant-1) yield when compost was added @ 10 t ha-1under control condition. at 5 dsm-1salinity condition, highest seed yield (8.63 g plant-1) was obtained from biochar @ 5 t ha-1and the lowest seed yield (4.79 g plant-1) when compost was applied @ 5 t ha-1. under 10 dsm-1saline condition, highest 48 ferdous et al. seed yield (2.95 g plant-1) was obtained when soil was treated with compost @ 5 t ha-1 and lowest (2.19 g plant-1) when compost added in the soil @ 10 t ha-1. conclusion from the results it may be concluded that salinity decreased plant height, leaf, stem, root dry matter and yield contributing parameters of soybean plant. application of water hyacinth compost and rice husk biochar had positive effects on mitigation of negative effects of salinity stress on soybean growth and yield. however, rice husk biochar at the rate of 5 t ha-1 showed best result to mitigate salinity stress at low salinity (5 dsm-1) condition. references abou el-magd, m. m., m. f. zaki and s. d. abou-hussein. 2008. effect of organic manure and different levels of saline irrigation water on growth, green yield and chemical content of sweet fennel. australian j. basic and appl. sci.2(1): 90-98.. akhtar, s. s., n. a. mathias, n. muhammad, a. z. zahirand l. fulai. 2015. interactive effect of biochar and plant growth-promoting bacterial endophytes on ameliorating salinity stress in maize. functio. plant biol. 42: 770–781. ali, m. a., m. t. islam and m. t. islam. 2004. effect of salinity on some morpho-physiological characters and yield in three sesame cultivars. j. bangladesh agric. univ.3: 209-214. asai, h., b. k. samson, h. m. stephan, k. songyi khan gsuthor, k. homma, y. kiyono, y. inoue, t. shiraiwa and t. horie. 2009. biochar amendment techniques for upland rice production in northern laos 1. soil physical properties, leaf spad and grain yield. field crop res. 111: 81-84. bernstein, l. 1975. effects of salinity and sodicity on plant growth. annu. rev. phytopathol. 13: 295-312. chan, k. y., l. v. z. wieten, i. meszaros, a. downie and s. joseph. 2008. using poultry litter biochars as soil amendments. australalian j. soil res. 46:437–444. chan, k. y., l. v. zwieten, i. meszaros, a. downie and s. joseph. 2007. agronomic values of green waste biochar as a soil amendment. australian j. soil res. 45:629–634. debosz, k., s. b. o. petersen, l. k. kure and p. ambus. 2002. evaluating effects of sewage sludge and household compost on soil physical, chemical and microbiological properties.appl. soil ec.19: 237-248. food and agricultural organization (fao). 2013. land and plant nutrition management service. http://www.fao.org/ag/agl/agll /spush. gaballah, m. s. and m. s. mandour. 1999. increasing drought resistance of wheat plants during grain filling byusing chemical desiccants. j. sci. mansoura univ., 25(2): 833-841. gomez, a. a. and a. a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. 20-2015. gopal, and k. s. dube. 2003. influence of soil and foliar application of potassium on growth, nutrient utilization, yield and quality of sugarcane (saccharum officinarum l.). new botanist. 21(1-4): 13-20. hussein, m. m., l. k. balbaa and m. s. gaballah. 2007. salicylic acid and salinity effects on growth of maize plants. res. j.agric.biol. sci. 3(4): 321-328. mitigation of salinity stress in soybean 49 idrees, s., m. s. qureshi, m. y. ashraf, m. hussain and n. h. naveed. 2004. influence of sulphate of potash (sop) and farmyard manure (fym) on sugarcane (saccharum officinarum l.) grown under salt stress. pakistan j. life social sci. 2(1): 65–69. karim, m. a., m. a. e. nawata and s. shigenaga. 1992. dry matter production and distribution of mineral ions in different parts of plant in hexaploid triticale under salt stress condition. japanese j. crop sci. 61 (3):439-446. laird, d. a., p. d. fleming, d. d. davis, r. horton, b. wang, d. l. karlen. 2010. impact of biochar amendments on the quality of a typical midwestern agricultural soil. geoderma in press: geoderma doi:10.1016/j.geoderma.2010.1005.1013. leithy, s., m. s. gaballah and a. m. gomaa. 2010. associative impact of bioand organic fertilizers on geranium plants grown under saline conditions. electron. j. environ. agric. food chem. 9(3): 617-626. lynch, d. h., r. p. voroney and p. r. warman. 2005. soil physical properties and organic matter fractions under forages receiving composts, manure or fertilizer. compost sei. util.13: 252261. raafat, n. z. and e. e. r. tharwat. 2011. improving wheat grain yield and its quality under salinity conditions at a newly reclaimed soil using different organic sources as soil or foliar applications. j. appl. sci. res. 7: 42-55. raptan, p. k., hamid, a., khaliq, q. a., a. r. m. solaiman, a. j. u. ahmed and m. a. karim. 2001. salinity tolerance of balckgram and mungbean: ii. mineral ion accumulation in different plant parts. korean j. crop sci. 46: 380-394. srdi. 2010. saline soils of bangladesh. srmaf project, ministry of agriculture, bangladesh. 1–60. stamatiadis, s., m. werner and m. buchanan. 1999. field assessment of soil quality as affected by compost and fertilizer application in a broccoli field (san benito county, california).appl. soil ecol.1:217-225. sultana, n. t., r. ikeda and h. itoh. 1999. effect of salinity on yield attributes and yield inrice genotypes. environ. expt. bot. 42: 211-220. tanji, k. k. 1990. agricultural salinity assessment and management. asce manuals and reports on engineering practice (usa). tejada, m., c. j. l. garcia, gonzalez and m. t. hernandez. 2006. use of organic amendment as a strategy for saline soil remediation: influence on the physical, chemical and biological properties of soil. soil bid. biochem. 38:1413-1421. verheijen, f. g. a., s. jeffery, a. c. bastos, v. d. velde and m. i. diafas. 2009. biochar application to soils: a critical scientific review of effects on soil properties, processes and functions. official publications of the european communities: luxembourg. eur 24099 en. 61. wanas, s.a. and w. m. omran. 2006. advantages of applying various compost types to different layers of sandy soil: 1. hydro-physical properties. j. appl. sci. res. 2(12): 1298-1303. microsoft word final.doc � �������� ��� �������������������������� ����� �!��"#���$%&'�#��%��#!"(�!&�)%�*$�!��(+����$%&'������ �!��"#���$%&'�#��%��#!"(�!&�)%�*$�!��(+����$%&'������ �!��"#���$%&'�#��%��#!"(�!&�)%�*$�!��(+����$%&'������ �!��"#���$%&'�#��%��#!"(�!&�)%�*$�!��(+����$%&'� ���� $�(,%��&$�$�(,%��&$�$�(,%��&$�$�(,%��&$� !((� !((� !((� !((������+ ��+ ��+ ��+ ��������� ���� -�����. ��-�����. ��-�����. ��-�����. ��������(��-�����,� �/���(��-�����,� �/���(��-�����,� �/���(��-�����,� �/�������-���� / 0��/���-���� / 0��/���-���� / 0��/���-���� / 0��/�1111��-��(��/2��-��(��/2��-��(��/2��-��(��/2����������-����,� �/�������-����,� �/�������-����,� �/�������-����,� �/��������� ��03��#� �� 4 �#��/�����(3�3/������#%��#���50 ���$�5� 32��3��6��� ���27������ 1$�5� 32��3��6�(�/��(4/��4�����+��-72�� /�� ���"0� � �#� �� 4 ����3� ����#%����7��850 ��'�9/50 ����� �� � 5�����4���03 � ��� 2�: ��1�;1<7� ���4�2� .�7�=� � .�7�=� � .�7�=� � .�7�=� � ��#�8/�4 �5 ���� /�����3� ��>03���7/���� � �8 3 �43�8 3 �43�8 3 �43�8 3 �43���� � ��� �?5� /2��3� =� � 4���043��� �3� 3 �� �03�� #� �� 4 � #��/����� (3�3/���� ./ � ����>� �6� �������� ��03��#� �� 4 � %� 3/303����0 /�������������������������1�3�� 6/����03� 3 �� �66�43 � �6� 5 �4��/��� 4 �5 �� @/9��= ��3�� 5�3�3��� ���3/��� ���� 6����=���� 7/���� �6� 044���/��� >03��4 �5 �� ���?5� /2��3�=� ���/���03�/���� ����2/9���4�25��3��8��4:��� /���=/3 �6�0 � �5�/4�3/�� �� �� � 0�3 � �@������ 3 �3�5���3� �/� 3�����8� ���/�2�3� ��6��a*�������!� �b��� =� �� ��3� �66�43��� /��/6/4��3�7� 87� 3 �� 5 �4��/��� �8/� 4 �5 �� �� 6/8 �� ���� 3/4:� 7/��� ��6�8�3 �3 ��>03��@� /�3/� �=� ���66�43��� /��/6/4��3�7�� �� /� � 3�6/8 ��7/�����6��a*� ���1����3� ��������1����3� ���������!��b����1����3� �����������1�3� �����=� � �4� ���� = ��� 3 � �� =� �� � �=�� �63� � 5�3�3�� ���� 3 �� 7/���� =� � 3 �� ��=� 3� = ��� � �=�� �63� � = ��3�����6����=������/��8�3 �3 ��7�� �� � ��=� ���� � 5�@� /�3/���/�� � @� 3�/���?�� = /4 � �=���/�4�� / 3��3�8�3=����3 ��7�� ��� � %�3 ��043/��%�3 ��043/��%�3 ��043/��%�3 ��043/������ ���� ��6 �2� ��6��������� �� �=�>03��� ���4� �4 �5�� � ��� ���8�03������2/��/��� �43� � ��6� �����40�3/@�3���0��� �>03��/���������� ����#%�����b����03��4 �5 �0 0���7�� �=�/�� /� ��2��/02� /� �����2��/02���=�������%��3 � ������ ��3 � ��� ���� ����028� ��6�6/����4 �5 �� �=��/�� �8/� �� �����2����3 �2�= ��3��5�3�3���50� ��4 �5��34��� ��@� 7�4�22�����03��4 �5����� ���7� �=�� /22��/�3���63� � � @� 3��6� �8/�4 �5 �� � �� �8/�4 �5�87�3 �/ ���30 ���66�43���87�3 ��5 �4��/��� 4 �5 ���� /�� ��3 ��6� 2� �40�3/@�3��� �8/�4 �5�87�0 /����/66� ��3���@����6�� ���/4�����/�� ���/4� 6� 3/�/9� �� ��/3/�����7� 3 �� 6� 2� � �@��8����0 /����@� ��� � ��6�4 �2/4��� 6� 3/�/9� � /��5�3�3�� 4 �5 ��������6� 3/�/9� �0 ��/��50� ��4 �5 �� �� � /�0���6� 3/�/9� ��6�5 �@/�0 �4 �5 �4����66�43�3 �� 08 �c0��3� 4 �5�� . ��� �3� ���� ����b�� �5� 3��� 3 �3� 3 �� 8�33� � 5� 6� 2��4�� �6� >03�� 4 �5� =� � �8 � @����63� �5�3�3��40�3/@�3/���4�25� ���3��3 �3��63� �= ��3��� ��5 �4��/��� ���02��4 �5 �5� /3/@��7� /�6�0��4��� 3 ��7/����� �=����� ��4���2/4 ��6� 08 �c0��3� /4��4�25� ���3��6����=�����= ��3��� ��� ������'�03�2���������d0�7702�����-��/ 099�2��� ����;�� �5� 3���3 �3�= ��� /4��4 �5�5 �4�����87� ����8��4:� �2�� /3�5 ��04��� /��/6/4��3�7� /� � 7/�����. ��� �3� ���� ������� �� �� �5� 3��� 3 �3� 3 �� 5���3� �2��� /4�� 5 ��04��� /��/6/4��3�7� /� � � 7/�����= ���/3�=� �5 �4�����87�� �/�4 ���(� 8��/���40���3�������>03��4�25� ���3��3 ���3 �3��6� 3 �� 5���3��0 � /4������6����=��� ��=�3��3����� ��������8 � @���3 ��8���6/4/����66�43��6� ���02��/�� 3 �� 4 �5� �3�3/���� ��/�� ���� (����:/� ����1�� �5� 3��� 3 �3� 3 �� ���02� � �/:�� 8��4:� �2� ���� � �0���03�� �=/���� �5 �4�����3���5/02�5�557�/25 �@���3 ����3�?�7/�����6�5�557�4�25� ���3�� 2�/9��� (�3�7��� �7���� ���� � � �� ���b��� �5� 3��� 3 �3� 3 �� 7/���� �6� ��/��� 80�8� /�4 �� ��� 08 3��3/���7� = ��� 5�3�3�� 4 �5� 5 �4����� /3�� � �� 6/��/�� � �@������ 3 �3� 3 �� 5 ��043/@/37� �6� �/66� ��3�4 �5 �/�6�0��4���87�3 ��5 �4��/���4 �5 �� � �6� ���3 ��5 � ��3� 30�7�=� �4� /����03�3�� � � �3 ���66�43 ��6�5 �4��/��� �8/�4 �5 ����7/��������7/�����33 /803� ��6��� /�����3� ��>03��� �;� . ����3����� -�3� /�� �����-�3 �� �-�3� /�� �����-�3 �� �-�3� /�� �����-�3 �� �-�3� /�� �����-�3 �� ����� ���� �� �?5� /2��3� =� � 4���043��� �3� 3 �� �03�� #� �� 4 � #��/����� (3�3/��� �6� �������� � �03�� #� �� 4 �%� 3/303�����#%���./ � ����>� /������������������������1�� �� �/���6��?5� /2��3��� 5��3� =� � /�3� ���2� /�� 3�?30 ��� �/� 3�7� �4/�/4� �5,� ;������ ��=� /�� � ���/4� 2�33� � �����e��� 3�3��� �/3 ����� ����b�e�� ���� �?4 �����8��� 5�3� /02� ����b� 2�c�� ��������� ��� �53/2��� ��@��� �6� 5 � 5 � 0 �������552�������@�/��8��� 0�5 0 ���� ��8�03�4 /3/4�����@���������552���%�� �8/� �� ���� 3 ��4 �5 ��@/9��= ��3��5�3�3��� ���3/��=� ��� �=������:�53� 6����=� /�� ����2/9���4�25��3��8��4:� �� /���=/3 � 6�0 � �5�/4�3/�� � 6����=/��� �4�22������2�����2��3� 5 �43/4� � 6� � 3 �� � 5�43/@�� 4 �5 ���63� � � @� 3��6� �8/�4 �5 ����4 �5��3�=� ��/@/����/�3��3=���c0��� ��@� �6� �� �=/����� /� ���� 3� �� >03��� ��@� /�3/� ��a*����6��� /� >03������!��b����6� 3� �� >03��=� ��0 ���� � 30�7� 2�3� /�� �� ��0�/3�5��3� /9��6� � /��/@/�0��� >03��4 �5�=� ��2�?��2�� ��6� 3/�/9� �=� ��55�/����3� 3 �� �3���6���������������b���:�� �����������������������b���:�� ����&�"�.�(�6� ��a*������� !��b���� � 5�43/@��7�� �5� � �4�22������5 �43/4� �� �� �8/�4 �5 � �=�������������������� �������������63� �3 �� � @� 3��6� �8/�4 �5 ��3 ��>03��4 �5 � �=������b��������������������1�� �� ���� �3� �=� ��0 ���� �����:�� ������������:�� ���� � 5�43/@��7� 6� ��a*�������!��b���� �03��4 �5�=� � � @� 3����3�������7 ��63� � �=/�����3� � @� 3���2��� ����6���4 �3 ��32��3�=� � � @� 3��� 6 �2���2��5��3� 6� � �4� �/���5���3�5�50��3/���� ��5���3� �/� 3� ����8� ���/�2�3� � =� �� �4� ����6 �2���� ����2�7� ���43���5���3 ���/8 ������ 3/4:�7/����=� �� �4� ����6 �2�= ���� 5��3��� ��4����43�����3��=� �� 3�3/ 3/4���7�����79���6����=/���'�2�9�����'�2�9����b���� ��4�2503� � 5�4:���� %##%( � � =� � 2���� 6� � ����7 / � �6� @� /��4�� 6� � 3 �� ��3�� �6� �/66� ��3� 5� �2�3� �� $/66� ��4� ��2����3 ��2��� �=� ��4�2503���6� � /��/6/4��4��6����=/���3 ��*($�3� 3�� � #� 0�3 �����$/ 40 /�#� 0�3 �����$/ 40 /�#� 0�3 �����$/ 40 /�#� 0�3 �����$/ 40 /��������� �������� �66�43 ��6�5 �4��/����66�43 ��6�5 �4��/����66�43 ��6�5 �4��/����66�43 ��6�5 �4��/��� �8/ �8/ �8/ �8/����4 �5 ����7/��������7/����5� �2�3� ��6�>03�4 �5 ����7/��������7/����5� �2�3� ��6�>03�4 �5 ����7/��������7/����5� �2�3� ��6�>03�4 �5 ����7/��������7/����5� �2�3� ��6�>03����� "���3�5�50��3/��"���3�5�50��3/��"���3�5�50��3/��"���3�5�50��3/������ "���3�5�50��3/���/��5� �0�/3�� ���/ �3 ��/25� 3��3�6�43� �6� �6/8 ��7/�����6� >03��� %3��/ �43�7��66�43 � 3 ��6/8 ��7/�����%��3 / � 30�7�5���3�2���/���� /�>03��=� ���3�@� /��� /��/6/4��3�7�/��3 ��6/ 3�7�� �803� /�� �4����7�� ��/3�=� �@� /��� /��/6/4��3�7�87�3 ��5 �4��/���4 �5 �� �8�������%��6/ 3�7�� �5���3�2�� � =� � �4� ���� 1��;� 3�� 1;�;� ���� /�� �4���� 7�� � 3 �� /� � 3� �028� � �6� 5���3 �2��� ������� =� � �4� ���� = ��� 3 �� �a*��� =� � 5 �4����� 87� 5�3�3��� = /4 � =� � 6����=��� 87� ���3/�� �1��b��� �� ��=� 3��028� ��6�5���3 �2����1�����=� ��8 � @���= ���>03��� �=���63� �= ��3�� / � � 0�3�=� � /2/�� � 3�� 3 �3�= ��� >03�� � �=�� �63� � 3 �� 6����=� ������ %�� 4� �� �6� 3� �� >03��� 5���3�2�� �=� � ��3� �66�43��� /��/6/4��3�7�87�3 ��5 �4��/���4 �5 ��"���3�2����6�3� ��>03��=� � �4� �����b�;�3��1���� ����1����3��1����� � 5�43/@��7�/��3 ��6/ 3�7�� ����� �4����7�� �� ���� "���3� �/� 3�����8� ���/�2�3� "���3� �/� 3�����8� ���/�2�3� "���3� �/� 3�����8� ���/�2�3� "���3� �/� 3�����8� ���/�2�3� ���� ��5���3� �/� 3�����8� ���/�2�3� ��6��� /���a*��������3� ��>03���!��b����=� ����3��66�43��� /��/6/4��3�7��0��3���/66� ��3�5 �4��/���4 �5 �/��8�3 �3 ��7�� �� �8������� ���02� /4��7� /� � � 5���3� �/� 3��6��a*�������!��b���=� ��8 � @���= ���3 ��>03��=� �� �=���63� �5�3�3���= /4 � =� �6����=���87����3/������/3�=� ���=� �= ���� �=���63� �= ��3�����6����=�5��3�/��8�3 �3 ��7�� �� (/2/�� � � 0�3 � =� �� �� �� �8 � @��� /�� 4� �� �6� 8� �� �/�2�3� �� �� /� � � 8� �� �/�2�3� � =� �� �4� ����= ���>03��� �=���63� �5�3�3���������3/���������=� �3 ���3 �3��6�= ��3�����6����=�/��8�3 � ��� " �4��/���#�8/�� �5 ��66�43 ����(044���/���$� /����� � ���03�� 3 ��7�� �� �� /� � �5���3� �/� 3�����8� ���/�2�3� �2/� 3�8��/�6�0��4���3 ��6/8 ������ 3/4:�7/���� �6�>03��� ���� �/8 ��7/����/8 ��7/����/8 ��7/����/8 ��7/������� ��6/8 ��7/�����6��a*��� ��� /������!��b����3� ���=� ��66�43��� /��/6/4��3�7��0��3��5 �4��/��� 4 �5 �� �8������� �� /� � 3�6/8 ��7/��� ��6�1����3� ��������1�;��3� ����=� �� �4� ����/���a*��� = ��� /3�=� �5 �4�����87�5�3�3�� ���� ���3/��� � 5�43/@��7� /�� 3 �� 6/ 3� 7�� �� �� ��=� 3� 6/8 ��7/���� �1����3� ����1����3� �����=� ��8 � @���/���a*���= ���/3�=� �� �=���63� �:��5/���3 �������6����=� ����= ��3�� %�� 3 �� �4����7�� � 3 �� � 0�3�=� � /2/�� � 3�� 3 �3��6� 6/ 3�7�� ��(/2/�� �7�� 3 �� /� � 3� 6/8 ��7/�����6�1����3� ����=� � �4� ����6 �2�!��b���= ���/3�=� �5 �4�����87�5�3�3��/��3 ��6/ 3� 7�� �� �� �4���� /� � 3� ������ 3� ����� 6/8 �� 7/���� =� � �4� ���� = ��� � �=�� �63� � ���3/��� �� ��=� �6/8 ��7/����������3� �����=� � �4� ����/��!��b���= ���/3�=� �5 �4�����87�= ��3�����6����=� ���������1�3� ������%��3 �� �4����7�� ���� /2/�� � � 0�3�=� ��� ���8 � @������ ���� (3/4:�7/���(3/4:�7/���(3/4:�7/���(3/4:�7/������� (3/4:� 7/���� �6� �a*��� =� � /��/6/4��3�7� �66�43��� 87� 3 �� 5 �4��/��� �8/� 4 �5 � /�� 8�3 � 3 �� 7�� � � �8�������%��3 ��6/ 3�7�� ��3 �� /� � 3� 3/4:�7/�����6����1�3� ����=� � �4� ����= ����a*���=� � � �=���63� �5�3�3���= /4 �=� �6����=���87�;����3� ����= ���� �=���63� ����3/��� ����=� 3� 3/4:� 7/��� � �6�;���� 3� ���� ����;��b� 3� ����=� �� �4� ����= ����a*���=� � � �=���63� � 6����=����� = ��3�� � 5�43/@��7���� /2/�� � � 0�3�=� ��� ���8 � @���/��3 �� �4����7�� ��(3/4:�7/�����6�!��b��� =� � /��/6/4��3�7��66�43���87�3 ��5 �4��/��� �8/�4 �5 �/��3 ��6/ 3�7�� �803�3 � ��=� ���� /��/6/4��3� @� /�3/���/��3 �� �4����7�� �� �� /� � 3� 3/4:�7/��������b�3� �����=� � �4� ����= ���!��b���=� � � �=���63� �5�3�3���= /4 �=� �6����=���87�7/�����6�;����3� ����= ���� �=���63� ����3/��/��3 ��6/ 3� 7�� �� �� ��=� 3� 3/4:�7/�����6���1b�3� ����������11� 3 ����=� �� �4� ����= ���!��b���� �=�� �63� �6����=����������= ��3�� � 5�43/@��7�� ���� ,� @� 3�%���?,� @� 3�%���?,� @� 3�%���?,� @� 3�%���?���� ,� @� 3�/���?��6��a*��� ������6 �2�1����3��1��������1��;�3��1����/��3 ��6/ 3�7�� ����� �4���� 7�� �� � 5�43/@��7� � �8��� ���� �� /� � 3� � @� 3� /���?� �,%�� =� � �8 � @���= ����a*��� � �=�� �63� ����3/���1���������5�3�3���11�����%��4��3 � 3�3 ��,%��1��������1�����=� �3 ����=� 3�= ���3 �� 4 �5�� �=���63� �6����=������� �� � @� 3�/���?��6�!��b���@� /���6 �2�1����3��11���/��3 ��6/ 3� 7�� �����1��;� 3��1���� /�� 3 �� �4����7�� �� �� /� � � � @� 3� /���?�=� ��8 � @��� /��!��b��� = ���5���3����63� �5�3�3���������3/��� ���� �8�����"���3� �/� 3�����8� ���/�2�3� ��6��� /�����3� ��>03��� ��66�43���87�5 �4��/���4 �5 � " �4��/��� 4 �5 ���� "���3�2��������� "���3� �/� 3��2�� �� ���/�2�3� ��22�� �� /� � �� �� /� 3� �� �� /� 3� �� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� f ��3� "�3�3�� *��3/�� �����=� 1;�;� 1;�;� 1���� 1��;� 1���� ����� 1��b� 1���� 1��1� �b�;� ���1� 1���� 1���� 1;��� 1���� 1���� ���;� 1���� 1���� 1���� ��b�� 1���� ����� ��b�� 1���� 1���� 1���� 1���� ���b� ��b�� ��b�� ����� ���b� ����� �;��� ����� ���b� ����� �;��� ���1� ����� ���1� ����� ����� ����� �1��� �1�b� ����� *($������� �a��e�� &(� ���� ���� ��b� &(� ��;� &(� ��b� &(� 1��� &(� ��;� &(� 1��� &(� ;��� &(� ���� &(� b�b� &(� ���� ���� ;��� ���� ���� �b� . ����3����� �8�������/8 ��7/�����(3/4:�7/�������� � @� 3�/���?��6��� /�����3� ��>03��� ��66�43���87�5 �4��/���� 4 �5 � " �4��/��� 4 �5 ���� �/8 ��7/�����3 ����� (3/4:�7/�����3 ����� ,� @� 3�%���?��e�� �� /� � �� �� /� 3� �� �� /� 3� �� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� ����� ��� ����� �1� f ��3� "�3�3�� *��3/�� �����=� 1���� 1���� 1�;�� 1���� ����� 1���� 1���� ����� ����� 1���� ����� ����� ����� ���1� ��;1� ����� ;��b� ���1� ;���� ;���� ;��1� ����� ;��1� ����� ��1b� ���b� ;���� ��11� ����� ;���� ���1� ��;�� 11��� 11��� 1���� 1���� 1��;� 1���� 1���� 1���� 1���� 11��� 1���� 1���� 1���� 1���� 1���� 1��;� *($������� �a��e�� ��1�� ���� ����� b��� ��1�� ���� ����� ���� ����� ;�;� ����� ;��� ��b;� ���� &(� ��1� �� �� �� �� ���� ��/3/�����7��� �� ��2�0�3��6�6� 3/�/9� �� ��0 ���/��5�3�3��4 �5 �3��2�?/2/9��3 ��308� �7/������ � �� � 0�3�� �� 5� 3/��� �6� 3 �� � /�0��� 6� 3/�/9� � �2�/� � /�� 3 �� 6/���� ���� 3 �3� �66�43 � 3 �� ��?3� 4 �5�� . ����3���������b�� �5� 3�����8�33� �5� 6� 2��4���6�>03��� �=���63� �5�3�3��4�25� ���3��3 ��>03�� � �=���63� �= ��3�� ��50� ��4 �5��/:�����3/���� ���66�43���3 ��6����=/���>03��4 �5��0��3�� � /�0� � � ��3� 3088�� ���= /4 �=� � �5���/ ��� 3 �� �/�� 6� 3/�/37� 3 �0� �8/����/4��� �/3 ����� 6/?�3/���� �� ��=� 3�6/8 ������ 3/4:�7/�����6�>03��=� � �4� �����= ���/3�=� �5 �4�����= ��3�����6����=���/ =� � �3�������������� �� �5� 3���3 �3�= ��3�4 �5 �� �� ��@7�4�� 02� ��6��03 /��3 �� �� �/���03 /��3 � �� ����� �����0 /���6����=�5� /���3 �3��66�43 �3 �� 08 �c0��3�4 �5��-�� ���3������������ �5� 3��� 3 �3� 6����=/��� /�� 022� � ����� 3�� ��� ���3/��� �6� �/�� 5 �5� 3/� � /�4�0�/��� ��04��� �03 /��3 � �@�/��8/�/37�� = /4 � 2�7� 4�0 � � 3 �� ��=� � 6/8 �� 7/���� �6� >03��� (/�� � ���� � =�3 /� ����b�� �� �� �5� 3���3 �3�6����=/�����4 �� � �3 �� �/��6� 3/�/37�������� ��6/8 ��7/�����6�>03��=� � /� � �6����=���87�5�3�3��4 �5 �2/� 3�8���0��3��3 �� � /�0����66�43��6� 6� 3/�/9� �� = /4 � =� � 0 ��� /�� 5 �4��/��� 5�3�3�� 4 �5 �� %�� 5�3�3�� 4 �5 � �?4� /@�� �2�0�3� �6� 6� 3/�/9� � =� �� 0 ��� 3��2�?/2/9�� 3 �� 7/����� � � �� � 0�3� �� 5� 3/��� 6� 3/�/9� � �2�/�� /�� 3 �� �/�� � � � /�0� ����� /3��66�43��� 3 �� 044���/���4 �5 ��. ����3����� ����b�� �5� 3��� 3 �3� >03��4 �5 ��63� � 5�3�3�� 40�3/@�3/��� 5� 6� 2��� 8�33� � 4�25� ��� 3�� >03�� �63� � = ��3�� �� 50� �� 4 �5�� ���3/�� �� �� �66�43���3 ��6����=/���>03��4 �5��0��3�� � /�0� �� ��3� 3088�� ���6����3/���= /4 �=� � �5���/ ���3 �� �/��6� 3/�/37�3 �0� �8/����/4����/3 �����6/?�3/���/��3 �� �/��� ����=� 3�6/8 ������ 3/4:�7/�����6�>03�� =� �� �4� �����= ���/3�=� �5 �4�����= ��3�����6����=����� � ���4�0 /�����4�0 /�����4�0 /�����4�0 /������ ���� %��4��4�0 /����3 �� � 0�3 ��6�3 / � 30�7�/��/4�3���3 �3�6/8 ������ 3/4:�7/��� ��6��� /�����3� ��>03�� =� ��3 �� /� � 3�= ���>03��4 �5 �� ��� �=���63� �5�3�3��40�3/@�3/����6����=���87����3/����/8 ��7/���� �6�>03����4 �� ���= ���>03��4 �5 �� ��� �=���63� �= ��3�����6����=����� ���� #�6� ��4� #�6� ��4� #�6� ��4� #�6� ��4� ���� ���� � ��=�3��%��"��(������(/�� ��������(��(� �6���������66�43��6�=/�3� ����02� ��6�3 ���/3 ������4���27� ����5 ��043/@/37��6� 044���/���4� ������?53���� /4���������;��� �/ =� �� ���������*����/������(�����-��������������020��3/@���66�43��6��/66� ��3����@� ��6�2��0 � ���� 3 ��5 7 /4���5 �5� 3/� ��6� �/������%��/���(�4��(�/��(4/������1��1��� ��#%���������� ��03��#� �� 4 �%� 3/303�������b���03�������03����8 /4 ���������� ��&�= �����#%������ ����� ��� " �4��/���#�8/�� �5 ��66�43 ����(044���/���$� /����� � ���03�� � ��� ���(������#�����'�03�2���������66�43��6�5 �4��/���4 �5 ������/3 ����� �3� ���� /4��7/��� ����� �4���2/4 ��6�/3 � �3�3/����������� /4��#� ���b����������� '�2�9��.���������������'�2�9����b���(3�3/ 3/4���5 �4��0 � �6� ��� /40�30 ���#� �� 4 ������������� %�3� ��3/�����#/4��#� �� 4 �%� 3/303��8��:���� ��f/��7�����(�� �%�4���&�=�)� :��55�1��;b��� ��/��� "��-�� ����&�� (�� (����:/�� ���1�� �66�43� �6� 5 �4��/��� 4 �5 � ��� 6� 3/�/9� � �c0/ �2��3� �6� �5/02� 5�557��"�5�@� � �2�/6� 02���%��/�������� ����1b�����������;�� . ����-��-��#���-��� 2�������-�����f� �8�����b��%�3�� �3����03 /��3�2�����2��3�=/3 �/�� ���/4� 6� 3/�/9� � ���� � ���/4�2��0 � � 6� � 3=�� ��2/���3� 4 �55/��� 5�33� � �� " �4�� �6� 3 ��&�3/����� f� : �5����%�3�� �3���-�����2��3�6� �� �5�" ��043/�������(�/���� 3/�/37��������-� 4 �� ���b���������� ��� /���#� ��%� 3����7��850 ��'�9/50 ��55���1������ . ����-������(��-�����,� �/���-���� / 0��/������-��(��/2���������66�43 ��6�5 �4��/���4 �5 ���� 3 �� 5���3��2��� /4��5 ��043/@/37����� �/��6� 3/�/37���������� ������ /��1�������b�� -�� ��� a��� -�� a�� -������ -�� ��� &�/ � ���� &�� &�� "�337�� ������ �66�43� �6� 022� � 4 �55/��� ���� 6����=/������3 ��5 ��043/@/37��6� /4������ ����� �5���� /4��1���b��b;�� d0�7702��-���������������-��-��/ 099�2�������;���66�43�5 �4��/���4 �5 ����7/�����6� 044���/��� 3 �� 5���3����2��� /4���! 79�� �3/@����%��/�������� ��������1���1�1�� (�37��� �7�����a������"��&��� � �����b����66�43��6�6� 3/�/9� ����5�3�3������3 �/ � � /�0����66�43���� 044���/�����/����%��/�������� ��������1���1���� (/�� ��.��.������!��"��� =�3 /�����b��-�/�3����4���6� �/�� 6� 3/�/37� /�� 3 �� /�� �=/3 � /�4� 5� �3/��� ���02� �/��4 �55/��� �c0��4���%��/�������� /4��(4/���b������;�� � � � � � � � � � � � � � � � � � � bangladesh agron. j. 2017, 20 (1): 25-29 growth and yield performance of potato varieties under different planting dates b. ahmed1*, m. sultana2, m. a. h. chowdhury3, s, akhter4, and m. j. alam5 1plant physiology division, bari, gazipur 2tuber crop research sub-center, bari, seujgari, bogra 3upazila agriculture officer (lr), department of agricultural extension khamarbari, dhaka-1215 4agronomy division, bari, joydebpur, gazipur 5soil science division, bari, gazipur *corresponding author: kbdahmed@gmail.com key words: growth, phonological, sowing date, variety abstract an experiment was conducted during 20 november 2015 through march 20i6 to assess the effect of planting dates on growth and yield performance of three potential varieties of potato at plant physiology research field, bangladesh agricultural research institute, gazipur. three planting dates (november 20, december 5 and december 29) and three varieties (var. bari alu-35, bari alu-40 and bari alu-41) were the treatment variables. the experiment was laid out in a randomized complete block design with three replications. maximum plant height (42.3 cm) was observed in 5 december sowing in var. bari alu-40. highest number of tuber/plant (13) was recorded from december 5 sowing in var. bari alu-41. the highest leaf area was found in december 5 sowing of bari alu-40 while the lowest leaf area in november 20 sowing in var. bari alu-35. the highest tuber weight/plant (97.25 g) was observed in var. bari alu-5 at december 5 sowing and the lowest tuber weight/plant (25.58 g) in var. bari alu-35 at november 20 sowing. the maximum potato yield (42.12 t/ha) was obtained at december 5 sowing of bari alu-35 followed by same date of var. barialu41. from the experiment it was revealed that the first decade of december is the optimum date for planting of potato due to the physiological maturity and tuber yield. introduction potato is the world's fourth-largest food crop after rice, wheat, and maize (haas et al., 2009; chakraborty et al., 2010; li, 1985 .this crop can be consumed as a vegetable and also as the major food item. its yield and quality are both dependent on variety and cultural practice as well as environmental condition, including rainfall, temperature, light, and co2 (dalla costa et al., 1997). potato produces the highest amount of energy per unit area and has the highest dry matter yield which may be 74.5% compared to wheat and 58% compared to rice. potato planting dates for each region is one of the factors that have a significant role in the performance of this product. proper planting makes all the environmental factors occurring at the time of emergence, and seedling establishment of appropriate. each stage of growth coincide with environmental conditions is desired. yield difference in delayed planting dates is caused by reduction in number of tubers per plant and shrinkage of leaves. potato planting date can be determined based on its growth season duration in any region. delayed planting dates cause yield reduction (peter et al., 1988). in bangladesh, the optimum time of sowing of potato is the second week of november, but in many cases the potato crops are planted under late 26 ahmed et al. sown condition due to delayed harvesting of transplanted aman. plant growth at delayed planting significantly reduced the vegetable growth of the potato plant because of lower temperatures in the end of october and earlier november. delayed planting reduced the yield of potato. plant dry bio-mass was higher by planting the potato earlier. the physiological causes that led to yield reduction in delayed planting of potato had not been reported from bangladesh. therefore, an attempt was undertaken to analyze the growth, development indices of different potato varieties and yield of potato in relation to planting date. materials and methods the experiment was conducted at plant physiology research field, bari, joydebpur, gazipur during rabi season of 2015-16. the soil was silty clay loam in texture belonging chhiata series under aez-28 having low organic matter (0.97%) and deficient in total nitrogen (0.056%), available phosphorus (12 ppm),exchangeable potassium (0.17 meq/100 g soil) and available sulpher (10 ppm). three planting date (november 20, december 5 and december 29) and three varieties (var. bari alu-35, bari alu-40 and bari alu-41) were studied and laid out in randomized complete block design with three replications. the plot size was 3.6 m x 5.4 m. the fertilizer dose was n23, p18 and k20 kg/ha and were applied in the form of urea, triple super phosphate (tsp) and muriate of potash (mop), and gypsum, respectively. one third of total fertilizers were applied as basal and two times urea fertilizer were applied as top dressed. a light irrigation was given before sowing of seeds for uniform germination. the seeds were sown with spacing of 30 cm x 60 cm in the depth of 5 cm in furrow followed by earthing up. the plots were weeded by hand during the early growth stage and irrigated by three times including germination. ten plants were collected from each plot at vegetative and flowering stage for leaf area measurement. the emergence and physiological maturity were taken when 70% of plants emerged and leaves of plants turned yellow, from observations at 23-days intervals. for tuber formation, four plants in each replication two or three times a week from about two weeks after emergence were dug up and were analyzed as in kawakami et al. (2003). the yield components data were taken from 10 randomly selected plants prior to harvest from each plot. the dry weights (dw) of tuber and leaf were measured after oven drying at 70oc for more than 72 hrs, and the leaf area index (lai) was calculated as the product of the measured leaf area and leaf dry weight ratio and the total leaf dry weight. the marketable (heavier than 20 g) tuber fresh and dry weights were recorded after physiological maturity for 12 plants of each cultivar and tuber type in each replication. harvesting was done at maturity stage. at harvest, the yield attributes and tuber yield was analysed as per mstat-c software. result and discussion sowing dates influenced vegetative (emergence to first flowering time) and reproductive growth stages (flowering to pod maturity time) of crops (akther et al., 2013). time of sowing also determines time of flowering and it has great influence on dry matter accumulation, seed set and seed yield (sofield, 1977). availability of light on potato canopy was almost 100% at earlier growth stage of potato (begum et al. 2015). the highest plant height (40.9 cm) was obtained from the december 5 sowing at bari alu-40 whether the lowest plant height (25.7 cm) at december 20 sowing in bari alu-35 at 45 days after planting (dap). highest leaf area (250 cm2/ plant) was observed at december 5 sowing at bari alu-35 while the lowest leaf area (120 cm2/plant) at november 20 sowing at bari alu-35. in case of dry matter, the 27 gowth and yield performance of potato varieties under different planting dates highest (16.30) was observed at bari alu-35 at november 20 sowing while the lowest (9.20) at december 20 sowing at the same variety. at 60 dap, the highest plant height (56.68 cm) was observed at bari alu-40 at december 20 sowing where the lowest (34.35 cm) at bari alu 40 at november 20 sowing. in case of leaf area, the highest (600 cm2/plant) was obtained at bari alu40 in december 5 sowing while the lowest leaf area (320 cm2/plant) at december 20 sowing at bari alu-41. the highest dry matter (21.54 %) was found bari alu41 at november 20 sowing while the lowest dry matter (17.34 %) at bari alu-40 at december 5 sowing (table 3). maximum plant height was observed in 5 december sowing in bari alu-40 (40.9 cm) while the lowest plant height (25.7 cm) in the same variety (bari alu-40) at 20 december sowing (table 3). plant height of november 5 and december 20 sowing was similar and significantly lower than the other sowings. highest number of tuber/hill (13) was recorded from december 5 sowing and higher than those of other two sowings. the highest leaf area (250 cm2/plant) was found in december 5 sowing of bari alu-40 while the lowest leaf area (136 cm2/plant) in november 20 sowing in bari alu-35. the highest tuber weight/plant (g) were observed at bari alu-35 at december 5 sowing time and the lowest tuber weight/plant (g) in bari alu-35 at november 20 sowing. in case of potato yield, the highest potato yield (42.12 t/ha) was obtained at december 5 sowing of bari alu-40 followed by bari alu-35 of the same sowing time. in the vegetative growth, the highest plant height, leaf area, leaf number was found in bari alu-41 at 45 dap but the highest leaf area at 60 dap in december 5 sowing at bari alu-35 sowing (fig. 2). delayed planting had adverse effect on leaf area resulting in lower total dry matter and ultimately reduced yield (shaheenuzzamn et al., 2015). reduced leaf growth resulted in smaller canopy and produce smaller tuber. due to difference of plantation time there was synchronization of the internal and external clock, which affect physiological process in plants and ultimately on yield of potato (hossain et al,. 2010). fig. 1. moisture level (%) at different days after sowing (das) and soil depth (cm) table 1. initial soil analysis values of the experimental plot soil parameters ph organic matter (%) total n (%) k (meq./100 g soil ) p ( g/g) s ( g/g) 6.6 1.09 .058 0.10 22.4 8.0 critical level 0.12 10 10 0 10 20 30 40 50 60 70 30 das 45 das 60 das 75 das m o is tu re l e ve l ( % ) days after sowing 31-45 16-30 0-15 28 ahmed et al. table 2. different growth parameters of potato as effected by sowing date and variety sowing date variety 45 dap 60 dap plant height (cm) leaf area (cm2/plant) dry matter (%) plant height (cm) leaf area (cm2/plant) dry matter (%) november 20 bari alu-35 34.5 120 16.30 48.65 341 20.30 bari alu-40 26.3 136 13.31 34.35 463 19.04 bari alu-41 35.3 231 12.83 44.10 314 21.54 december 5 bari alu-35 28.7 250 9.60 42.12 572 19.62 bari alu-40 40.9 200 14.21 41.25 600 17.34 bari alu-41 32.3 190 12.0 42.45 585 18.42 december 20 bari alu-35 25.7 237 9.20 47.32 563 18.61 bari alu-40 33.1 190 11.50 56.68 490 17.51 bari alu-41 34.3 240 14.63 46.21 320 21.30 cv (%) 7.63 20.24 7.50 7.58 16.37 6.85 lsd(0.05) 1.91 3.54 2.34 2.64 ns 3.51 table 3. effect of different sowing date on growth and yield of different potato varieties sowing date variety plant height (cm) leaf area (cm2) /plant tuber no/hill tuber weight/ hill (g) dry matter (%) tuber yield (t/ha) november 20 bari alu-35 72.5 372 9 255.8 19.0 28.65 bari alu-40 76.3 536 8 675.1 20.3 34.35 bari alu-41 85.3 530 9 563.1 21.4 35.38 december 5 bari alu-35 78.7 450 12 871.5 19.5 42.12 bari alu-40 70.9 400 9 864.5 19.3 31.25 bari alu-41 92.3 425 13 887.7 20.4 38.28 december 20 bari alu-35 65.7 537 8 659.8 18.5 27.32 bari alu-40 73.1 490 7 543.2 22.4 25.68 bari alu-41 60.1 360 9 602.7 20.3 24.38 cv (%) 5.63 20.24 8.97 7.85 6.76 7.58 lsd (0.05) 2.45 ns 4.27 5.62 2.31 4.28 conclusion it can be concluded from the findings on different parameters of yield of potato var. bari alu35 and bari alu-41 that sowing time at december (first decade) is the optimum for obtaining better yield of potato but reasonable yield could be possible upto december20. acknowledgement author is thankful to tuber crop research centre (tcrc), bangladesh agricultural research institute for suggestions and supplying the seeds in time. 29 gowth and yield performance of potato varieties under different planting dates references begum, a. a., m. n. islam, s. s. kakon, m. a. h. m. kamal, m. a. aziz, and s. k. paul. 2015. effect of sowing date of sweet corn on potato + sweet corn intercropping system. bangladesh agron. j. 18(2): 15-21. begum, f., b. c. kundu, and m. i. hossain. 2015. physiological analysis of growth and yield of potato in relation to planting date. j. bangladesh acad.sci. 39, (1): 45-51. chakraborty, s., n. chakraborty and a. datta. 2010. increased nutritive value of transgenic potato by expressing a nonallergenic seed albumin gene from maranthus hypochondriacus. proc. natl. acad. sci.usa, 97: 3724-3729. dallacosta, l., g. dellevedove, g. gianquinto., r. giovanardi, and a. peressotti.1997. yield, water use efficiency and nitrogen uptake in potato: influence of drought stress. potato res. 40: 19-34. haas, b. j., s. kamoun, m. c. zody, r. h. y. jiang, r. e. handsaker, l. m. cano, m. grabherr, c. d. kodira, s. raffaele and t. torto-alalibo. 2009. genome sequence and analysis of the irish potato famine pathogen phytophthora infestans. nature, 461: 393-398. hossain, m. m., m. m. rahman, a. h. m. r. h. chowdhury, b. ahmed and m.a. salam. 2010. photosynthetic potential and grain growth study in different boro rice cultivars. int. j. sustain. agril. technol. 6(9): 26-32. li, p. h. 1985. potato physiology. academic press inc. (usa):1-602. shaheenuzzamn, m., r. r. saha, b. ahmed, j.rahman and m. selim. 2015. green cob and fodder yield of sweet corn as influenced by sowing time in the hilly region. bangladesh j. agril. res. 40(1): 61-69. sofield, k., l. t evans, m. g. cook and f. wardlaw. 1977. factors influencing the rate and duration of grain filling in wheat. aust. j. plant. physiol. 4: 785-79. microsoft word 5. baj-223_revised.docx bangladesh agron. j. 2016, 19(1): 37-44 performance of french bean (phaseolus vulgaris l.) genotypes in sylhet region of bangladesh m. i. nazrul* and m. r. shaheb on-farm research division (ofrd), bangladesh agricultural research institute), sylhet, bangladesh. *corresponding authors: mi_nazrul@yahoo.com keywords: pulse crop. hill agriculture, seed yield, abstract an experiment was conducted at farming system research and development (fsrd) site, jalalpur and multi location testing (mlt) sites, zokigonj and moulvibazar during 2013-2015 to evaluate the suitable varieties (genotypes) of french bean for maximize the seed yield of the farmers. the experimental design was a randomized complete block (rcb) with 6 dispersed replications. eight bush bean genotypes were tested of which 3 were developed by bari (var. bari jharsheem-1, bari jharsheem-2, bari jharsheem-3), five local accessions: local-1(black), local-2 (white colour with chocolate spot at hylum), local-3 (coffee colour), local-4 (coffee colour with few chocolate spots) and local-5 (black with chocolate colour spots). the seed yields were varied significantly among the genotypes. all the local french bean lines performed better and produced higher seed yields compared to bari developed varieties. the maximum seed yields 2.66, 3.48 and 2.05 t ha-1 was produced by local-4 and local-5 at jalalpur, zakigonj and moulvibazer, respectively. so, local-4 and local-5 variety as the most promising one due their relatively good plant vigor and high seed yield potentiality. introduction french bean (phaseolus vulgarris l.) is commonly known as forashi sheem or jhar sheem in bengali (roy et al., 2006), belongs to the family fabaceae is an annual, diploid (2n=2x=22) species (galvan et al., 2003). it is a dual purpose crop grown as pulse and also consumed as immature tender fruits. it is an important legume, grown in the areas of jessore, rangpur, comilla, chittagong and sylhet in bangladesh. its dry seed contains 21.1 per cent protein, 69.9 per cent carbohydrates, 1.7 per cent fat, 381 mg calcium, 425 mg phosphorous and 12.4 mg iron per 100 g of edible part (ali and kushwaha, 1987). it is also reported that common bean is an important source of protein and calories in human diets (smithson et al., 1993). french bean is becoming popular for its tender pods and shelled beans. besides, it maintains soil fertility through biological nitrogen fixation in association with symbiotic rhizobium prevalent in their root nodules. the suitable variety in appropriate soil is the two important factors for higher crop production (dhanjal et al., 2001; shivakumar et al., 1996; singh et al., 1996). in sylhet region, farmers are generally cultivating local french bean cultivars of different in colour, shape, size and also vary in taste. some of these are high yielder, disease and drought resistant. three varieties of french bean have been developed by bangladesh agricultural research institute (bari), but inadequate information on their performance in surma kushiyara floodplain soil under aez 20. as such, the present study was under taken to identify the varietal performance of the local accession as well as bari developed varieties for sylhet region. materials and method 38 nazrul et al. an on-farm study was conducted on french bean in sylhet and moulvibazar districts during 2013-2014 & 2014-2015 under agro ecological zone of aez 20 with the objectives were to find out the suitable variety of french bean in respect of seed yield and income of the farmers. the experiments were conducted at farming system research and development (fsrd) site, jalalpur and multi location testing (mlt) sites, zokigonj and moulvibazar locations. the study area lays 24070' n latitude and 91067' e longitude under the surma‐kusiyara floodplains in bangladesh on an altitude of 10 meters. the monthly temperature and rainfall for the experimental sites are indicated in figures 1a-1b and 2a-2b. the climatic data of moulvibazar and sylhet districts showed that the average annual minimum temperature is 11.64 and 7.50°c and the average annual maximum temperature is 34.06 and 33.70°c and the annual average temperature nearly 18.62 and 25.25°c, respectively. as indicated in figure 2a-2b, the rainfall of two different locations is uni-modal, usually occurring during april to october, and total annual rainfall reached to 2354 and 4700 mm; whereas in december no rain at all except in the year of 2014 and lowest amount of rainfall occurs in january followed by february. however, in rest of the months total rainfall was ranged from 100 mm to just below 200 mm. rainfall increases gradually from the month of may and continued up to september. descriptions of the experimental locations fig. 1b. minimum, maximum and mean temperature (°c) pattern in moulvibazar of bangladesh, during 2013-14. fig. 2a. annual rainfall (mm) pattern in sylhet of bangladesh, during 2013-14 39 performance of french bean (phaseolus vulgaris l.) genotypes in sylhet region of bangladesh fig. 2b. annual rainfall (mm) pattern in moulvibazar of bangladesh, during 2013-14 the experimental design was a randomized complete block (rcb) with 6 dispersed replications. seeds were planted at 15 cm in row and 30 cm between rows with 2 seeds per hole. eight french bean genotypes (fig. 3) were tested of which 3 were developed by bari (var. bari jharsheem-1, bari jharsheem-2, bari jharsheem-3), five local accessions local-1(black), local-2 (white colour with chocolate spot at hylum), local-3 (coffee colour), local-4 (coffee colour with few chocolate spot) and local-5 (black with chocolate colour sport). fertilizers were applied @ 91-21-31-7-1-0 kg ha-1 of npksznb in the form of urea, tsp, mop, gypsum, zinc sulphate and boric acid, respectively. cow dung was used as per 5 t ha-1 during final land preparation. seeds of french bean were sown on 15-20 november and harvested at maturity on 25-28 february in each year. the trial was manually weeded at three weeks after sowing followed by irrigation, and other irrigations at six weeks after sowing and before harvest. the fungicides bavistin and tilt 250ec @ 0.5 ml/l of water were applied for controlling damping off and blight disease, respectively. data on yield and yield 40 nazrul et al. components were analyzed and mean values were separated by lsd test following gomez and gomez (1984). fig. 3. t1: bari jarsheem-1; t2: bari jarsheem-2; t3: bari jarsheem-3; t4: local-1 (black); t5: local-2 (white color with chocolate spots at hylum); t6: local-3 (coffee color); t7: local-4 (coffee color with few chocolate spots) and t8: local-5 (black with chocolate color spots) 41 performance of french bean (phaseolus vulgaris l.) genotypes in sylhet region of bangladesh results and discussions results of pooled data from two different years of french bean varieties and lines at fsrd site, jalalpur and mlt sites, zokigonj and moulvibazar area have been shown in table 1, 2 and 3, respectively. location wise detail descriptions were given below: location: fsrd site, jalalpur it was observed that the plant height was significantly influenced by the french bean genotypes where the highest plant height of french bean was recorded in local-5 (42.59 cm) while the lowest plant height (37.29 cm) in local-1. the maximum pods per plant were obtained in bari jharsheem-2 (13.62) that was statistically similar with that of bari jharsheem-3 (12.99) while lowest pods (7.84) per plant in line local-4. but, in case of pod length, the maximum was found in line local-3 (14.01cm) followed by local-5 (14.01cm). these findings corroborate with mozumder et al., 1996 and they found wide variation (8.9 to 17.7 cm) in pod length of bush bean genotypes. it is also remarked that all the local french bean lines provided the highest length of pod than that of bari developed varieties. among the genotypes seeds per pod were the maximum in bari jharsheem-1 (5.11) that was statistically followed by bari jharsheem-3 (4.95), and the lowest in line local-2 (3.95). in case of 100-seed weight, line local-4 was produced the maximum value (86.42 g) that was statistically followed by lines local-5 (81.96 g) and local-3 (80.79 g). the lowest 100-seed weight was gained in all of bari developed varieties. genotypic variation in 100-seed weight was also observed by other researchers in french bean (muthuramu et al., 2015; singh et al. 2014; mozumder et al., 1996) that also conformity with the present experimental findings. the french bean line local-5 produced statistically higher seed yield (2.65 tha-1) while lowest seed yield (1.29 t ha-1) was recorded in bari jharsheem-2 (table 1). the local lines of french bean contributed higher seed yield compared to that of bari developed varieties due to bigger size with higher 100seeds weight in local lines. table 1. yield contributing characters and seed yield of french bean at fsrd site, jalalpur during 2013-15 (pooled of 2 years). treatment plant height (cm) pods plant-1 (nos.) pod length (cm) seeds pod-1 (nos.) 100seed weight (g) seed yield (tha-1) bari jharsheem1 41.55 11.09 12.88 5.11 41.475 1.43 bari jharsheem2 40.73 13.62 12.04 4.44 32.79 1.29 bari jharsheem3 41.71 12.99 12.13 4.95 43.12 1.55 local-1 37.29 8.79 12.87 4.52 61.46 2.39 local-2 42.86 10.17 13.47 3.95 79.09 2.22 local-3 41.70 8.98 14.11 4.50 80.79 2.32 local-4 41.21 7.84 13.43 4.36 86.42 2.66 local-5 42.59 7.93 14.01 4.77 81.96 2.65 cv (%) 11.23 13.59 6.95 10.03 16.62 18.48 lsd (0.05) 4.58 2.61 1.23 0.59 18.11 0.60 location: mlt site, zokigonj 42 nazrul et al. the yield and yield contributing characters of french bean studied at zokigonj were furnished in the table 2, where plant height was found non-significant, but the higher plant height was recorded in bari jharsheem-3 (46.19 cm) while the lowest value (41.47 cm) in local-1. the maximum number of pods per plant of french bean was recorded in the line local-3 (12.74) and the lowest value (9.53) in local-4. these results are in agreements with the findings of singh and co-workers (singh et al., 1996), who reported that the number of pods per plant in french bean genotypes varied from 10 to 12. though the almost similar pod length was observed in all the tested genotypes but sharp difference was found between bari developed varieties and local lines. higher pod lengths were found in local lines which may be contributed to gain maximum seed yield of french bean. the seeds per pod are an important attributes of seed yield. number of seeds per pod varied significantly depending on the genotypes. the maximum number of seeds per pod was obtained for bari bush bean -1 (5.57). noor et al. (2014) studied nine french bean genotypes, of which bari bush bean -1 (5.80) contributed the highest number of seeds per pod. though, bari developed french bean varieties have some more number of seeds per pod, but the yield was lower which might be due to the smaller size of seeds. in case of 100seeds weight, the line local-5 gave the maximum weight (81.45 g) that was statistically followed by the lines local3 (80.82 g) and local-4 (79.00 g). the lowest value (38.67 g) of 100seed weight was recorded in bari jharsheem-1. the genotypic differences on 100-seed weight in french bean have also been reported by das et al. (2014). the highest seed yield of french bean was found in the line local-5 (3.48 t ha-1) that was statistically similar with that of all other local lines except the local-1. however, the lowest seed yield (1.58 t ha-1) was recorded in bari jharsheem-3 (table 2). furthermore, it is important to note that all the local lines of french bean were produced higher seed yield compared to bari developed varieties which might be due to the higher 100-seed weight of local lines. table 2. yield contributing characters and seed yield of french bean at mlt site, zakigonj during 2013-15 (pooled of 2 years) treatment plant height (cm) pods plant-1 (nos.) pod length (cm) seeds pod-1 (nos.) 100 seed weight (g) seed yield (tha-1) bari jharsheem1 41.77 10.20 13.34 5.57 38.67 1.82 bari jharsheem2 43.83 10.10 12.39 5.30 41.37 1.81 bari jarsheem-3 46.19 11.05 12.44 5.30 46.55 1.58 local-1 41.47 9.87 13.42 5.04 67.00 2.79 local-2 43.49 12.37 13.74 4.87 69.80 3.21 local-3 42.38 12.74 13.62 4.47 80.82 3.37 local-4 43.37 9.53 13.35 4.40 79.00 3.12 local-5 42.69 9.93 14.15 4.81 81.45 3.48 cv (%) 7.62 21.33 6.05 10.49 10.95 17.23 lsd (0. 05) ns 3.80 1.24 0.92 13.73 0.79 location: mlt site, moulvibazar at moulvibazar, bari developed varieties contributed maximum plant height (55.30, 54.92 and 54.25 cm) followed by local-5 (52.45 cm). the shortest plant height (45.61 cm) was observed in local-2. the maximum number of pods per plant was recorded in the var. bari jharsheem-2 (18.08) that was followed by bari jharsheem-1 (17.35) and bari jharsheem43 performance of french bean (phaseolus vulgaris l.) genotypes in sylhet region of bangladesh 3 (16.99) while the lowest value (8.36) in local-5 (table 3). the maximum pod length (14.20 cm) was measured in the var. bari jharsheem-1, followed by lines local-1, local-3 and local-5. the results are in agreements with the findings of rashid and hossain (2014), who reported that the longest pod (14.89 cm) was recorded with the maximum days after flowering in french bean. in case of seeds per pod, the higher value (5.87) was observed in bari jharsheem-1 that was statistically similar to the bari jharsheem-2 and the lowest (4.85) in local-4. most of the local french bean lines produced maximum 100 seed weight except local-1. the maximum 100seed weight of french bean was obtained in the line local-2 (57.50 g) that was statistically similar with that of all local lines (55.01 to 55.23 g). it is noted that the 100seed weight of bari developed french bean varieties was much lower than that of local lines. it might be due to smaller size seeds compared to local lines of bush bean. the lowest 100-seed weight (24.63 g) was gained in bari jharsheem-1. the maximum seed yield (2.05 tha-1) was recorded in line local-5 that was statistically similar to all local lines; on the other hand, bari developed french bean varieties produce lower yield ranged from 1.52 to 1.56 t ha-1 . the local lines gave higher yield might be due to the bolder size with higher 100-seed weight. these results are in consensus with the findings of singh et al. (2014) in french bean. another point is that the bush bean varieties bari jhahrsheem-1 and bari jahrsheem-2 were released for vegetables purposes. the seed yields were varied across the location might be due to the local climatic condition along with adaptability of french bean. table 3. yield contributing characters and seed yield of french bean at mlt site, moulvibazar during 2013-15 (pooled of 2 years) treatment plant height (cm) pods plant-1 (nos.) pod length (cm) seeds pod-1 (nos.) 100 seed weight (g) seed yield (tha-1) bari jharsheem1 54.92 17.35 14.20 5.87 24.63 1.56 bari jharsheem2 54.25 18.08 12.55 5.60 25.63 1.39 bari jharsheem3 55.30 16.99 12.48 5.21 26.07 1.52 local-1 49.40 11.89 13.81 5.49 40.00 1.91 local-2 45.61 11.19 13.61 5.25 57.50 1.95 local-3 48.64 10.74 13.73 4.87 55.20 1.99 local-4 47.90 8.55 12.70 4.85 55.01 1.98 local-5 52.45 8.36 13.79 5.54 55.23 2.05 cv (%) 6.87 19.75 6.69 12.42 4.08 3.23 lsd (0. 05) 5.51 3.98 1.40 0.80 1.61 0.22 conclusion this study showed that french bean genotypes (local-1, local-2, local-3, local-4, and local-5) significantly out yielded the varieties developed by bari. the local lines of french bean are very much popular due to bold seeded and takes less time to boil are utilizing for making pulse curry in sylhet. therefore, it could be suggested to the breeder to collect the local materials of french bean and released as variety with management practices. further research work may be undertaken on varietal development and cultural management 44 nazrul et al. practice of local french bean accessions to maximize the seed yield and higher economic return for the farmers. acknowledgement the authors would like to thank the bush bean growers for helping to collect bean germplasms to carry out this research and also acknowledged to the metrological departments of sylhet and moulvibazar districts of bangladesh for providing the weather data. references ali, m. and b. l. kushwaha. 1987. cultivation of rabi rajmash in plains. indian farm. 31(2): 2023. das, r., u. thapa, s. debnath, y. a. lyngdoh and d. mallick. 2014. evaluation of french bean (phaseolus vulgaris l.) genotypes for seed production. j. appl. nat. sci. 6(2): 594-598. dhanjal, r., o. prakash and i. p. s. ahlawat. 2001. response of french bean (phaseolus vulgaris l.) varieties to plant density and nitrogen application. indian j. agron. 46(2): 277-281. galvan, m. z., b. bornet, p. a. balatti and m. branchard. 2003. inter simple sequence repeat (issr) markers as a tool for the assessment of both genetic diversity and gene pool origin in common bean (phaseolus vulgaris l.). euphytica. 132: 297-301. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research, 2nd ed. john wiley and sons, new york. p. 194. mozumder, m. a., m. a. rouf, m. s. mollah and m. a. rashid. 1996. collection and evaluation of bush bean germplasms. in: m. a. rashid (ed.). research report on vegetable crops, hrc, rars, hathazari. pp. 35-39. muthuramu, s., v. k. paulpandi, s. sakthivel, k. ramakrishnan, r. karthik. 2015. assessing the performance of french bean (phaseolus vulgaris l) in district virudhunagar of tamilnadu. j. krishi vigyan. 3(2): 5-7. noor, f., f. hossain and u. ara. 2014. screening of french bean (phaseolus vulgaris l.) genotypes for high yield potential. bangladesh j. sci. ind. res. 49(4): 227-232. rashid, a. s. m. h and m. m. hossain. 2014. yield and quality of green pod production of bush bean (phaseolus vulgaris l.) as influenced by harvesting time. am. eurasian j. agric. environ. sci. 14(11): 1221-1227. roy, s. k., m. a. karim, a. k. m. a. islam, m. n. bari, m. a. k. mian and h. tetsushi. 2006. relationship between yield and its component characters of bush bean (phaseolus vulgaris l.). south pac. stud. 27(1): 13-23. shivakumar, b. g., c. s. saraf and r. r. path. 1996. performance of winter french bean as influenced by varieties, spacing and time of sowing. ann. agric. res. 17(4): 407-410. singh, d. p., a. l. rajat and s. k. singh. 1996. response of french bean (phaseolus vulgaris l.) to spacing and nitrogen levels. indian j. agron. 41(4): 608-610. singh, v., a. k. singh, h. k. and b. v. rajkumar. 2014. performance of french bean genotypes (phaseolus vulgaris l.) for seed yield and related traits under varanasi conditions. new agriculturist 25(2): 251254. smithson, j. b., o. t. edge and k. e. giller. 1993. diagnosis and correction of soil nutrient problems of common bean (phaseolus vulgaris) in the usambara mountains of tanzania. j. agric. sci. cambridge. 120: 233-240. bangladesh agron. j. 2017, 20 (1): 37-43 productivity of summer onion to different sources and levels of potash m.s. naher*, s. brahma, m.a. islam, m.b. sarkar, m.m. hasan and a.h.f. fahim spices research centre, shibganj, bogra, bangladesh agricultural research institute, bangladesh *corresponding author: mahmud.nahar@yahoo.com key words: summer onion; potassium; level; source; bulb yield abstract a field experiment was conducted at the research field of the spices research centre, shibganj, bogra, bangladesh in the summer season of 2013-2014 to find out the response of summer onion (var. bari peaj-3) to different levels and sources of potassium application. the experiment was laid out in a randomized complete block design with three replications. potassium fertilizer combinations were comprised of four levels (0, 60, 120 and 180kg ha -1) and two potassium sources viz. potassium chloride (kcl) and potassium sulphate (k2so4). a significant improvement in different growth and yield parameters of onion was observed in response to different sources and levels of potassium. the results indicated that the maximum plant height, leaves plant-1, length of leaf, length of bulb, diameter of bulb, average bulb weight, number of bulb per m2 and yield of bulbs were obtained from the onion crop which was treated with 120 kg k ha-1 from the sulphate of potash (sop) fertilizer. among the treatments the highest bulb yield (14.33 t ha-1) was obtained with 120 kg k ha-1 and the lowest (6.92t ha-1) from the control. the highest disease incidents (65.67%) were recorded from the control followed by the plots which were treated with 60 kg k ha-1 (62.28%). the lowest disease incidence (49.22%) was recorded from 180 kgha-1 sop treated plot. application of 120 kg k ha-1 from k2so4 along with a blanket dose of n100p50s20b1.5zn4 kgha-1 and 5 ton cowdung ha-1 appeared to be the optimum dose for maximizing the bulb yield of summer onion. introduction onion (allium cepa l.) is one of the important commercial vegetable and spice crops of bangladesh. it produces 17.04 lakh mt of onion from 4.19 lakh acres area (bbs, 2015). the average yield of onion in bangladesh is far below 11 t ha-1 (bbs, 2015) as compared to the world average of 19.32 t ha-1. onion is mainly produced in the winter season.but cultivation in summer season is constrained due to adverse weather and proper cultural practices (islam et al, 2008). by introducing drought tolerant onion varieties along with good cultural management, this may help increase onion production in bangladesh. bari has released three summer onion varieties for cultivating in the summer season. there is a significant response of onion to both inorganic and organic fertilizer (nasreen et al., 2000 and ullah, 2003). potassium plays an important role in onion production and responsive to potash application like other tuber and root crops. among the various nutrients required to produce high yield of onion, potassium is considered to be very important element due to its influence on translocation of photosynthates, storage quality, bulb size, bulb numbers and yield per plant (sangakara et al., 1993). potassium is one of the three major nutrients taken up by the plant in large quantities and an adequate level of potassium increases crop resistance to various diseases, stalk and stem breakage during stress conditions (razzaque et al., 1990). chloride in kcl may cause burning mailto:mahmud.nahar@yahoo.com 38 naher et al. of the leaves and deteriorate the onion bulbs; on the other hand sulphur in k2so4 improves the quality of the onion bulbs. among different sources of potassium, sulphate of potash (sop) contains sulfur that may lead to more growth and development as compared to muriate of potash (mop) for onion production (nabi et al, 2010). therefore, the experiment was undertaken to determine the response of summer onion (var. bari peaj-3) to different levels and sources of potassium application. materials and methods the experiment was conducted at the experimental fields of spices research centre in bogra,bangladesh. the experimental site represents agro-ecological zone (aez)-26 as “level barind tract” and situated at 24°51′ north latitude and 89°22 east longitude (fao, 1988).the soil of the experimental field belongs to grey terrace soil. it was developed from madupur clay and silty loam in texture. organic matter content of the soil was low (1.02%). the soil was acidic in nature (ph 5.7). total n and the exchangeable k status of the soil were also low. the available phosphorus, sulphur, boron and zinc contents were found to be either at par or below the critical level (table 1). summer onion var. baripiaz 3 was used as a test crop. table 1. physical and chemical characteristics of the initial soil texture ph om e x ch a n g e a b le m g e x ch a n g e a b le k e x ch a n g e a b le c a t o ta l n a va ila b le p a va ila b le s a va ila b le b a va ila b le z n a va ila b le c u % (c mol kg-1) (mg kg-1 soil) silt loam 5.7 1.02 1.06 0.10 3.03 0.071 11.2 8.6 0.14 0.56 0.07 critical level 0.8 0.20 2.0 14 14 0.2 2.0 0.2 there were seven treatment combinations viz. t1: 0 kg k ha-1 (control), t2: 60 kg k ha-1 from kcl, t3: 120 kg k ha-1 from kcl, t4: 180 kg k ha-1 from kcl, t5: 60 kg k ha-1 from k2so4, t6: 120 kg k ha-1 from k2so4 and t7: 180 kg k ha-1 from k2so4. the experiment was laid out in randomized complete block design (rcbd) with three replications. fertilizer with a blanket dose of n100p50s20b1.5 zn4 kg ha-1 and cowdung (5tha-1) was used. the experimental plots were prepared uniformly and mixed with well-decomposed cow dung. apart from potassium, all other fertilizers were applied to the soil during final land preparation. urea fertilizer was applied with three equal splits at basal, 20 dat and 40 dat, respectively. the size of seedbed was 3 m × 1 m with 20 cm height. the onion seeds were directly sown in the raised seedbed followed by irrigation. about 40 days old seedlings were uprooted from the seedbed and transplanted in the morning to the main field with the spacing of 10 cm × 15 cm followed by irrigation. intercultural operations like gap fillings, weeding and mulching were done whenever required. second and third irrigation was given at 20 and 30 dat, respectively. insect and diseases were also controlled with appropriate control measures. data 39 productivity of summer onion to different sources and levels of potash of plant height (cm), length of leaf (cm) and number of leaves per plant were recorded from the selected five plants in each plot at 30, 50, 70 and 90 days after transplanting (dat). the plant height (cm) was taken from the neck of the onion bulb to the tip of the longest leaf. the leaf length (cm) was measured from the pseudo stem to the tip of the leaf and the number of leaves from each plant. onions were harvested when more than 40% of leaves tops were bent down (khan and khan, 1990 and khokhar and jilani, 2000). the bulbs were placed for five days under partial shade in the open for curing. yield components data (length of bulb per plant (cm), diameter of bulb per plant (cm), single weight of bulb (g), number of bulbs per plot and yield of bulb (t ha-1) were collected and statistically analyzed using mstat-c computer package program (russel, 1994). the significance of the differences among the pairs of treatment means was evaluated by the duncan multiple range test (dmrt) at 5% level of probability (gomez, et al, 1984). results and discussion plant height the plant height was significantly influenced by different sources and levels of potash (table2). at 70 dat, the highest plant height (50.78cm) was recorded from 120 kg k ha-1 from k2so4 source and the lowest plant height (39.85cm) from the control.. similar effect was also recorded at 30, 50 and 90 dat. the rate 120 kg k ha-1 from k2so4 showed the best performance which might be due to the availability of optimum source and level of potassium than other treatment. hassanpouraghdam etal., (2008) also reported that different concentrations of n and k influenced height of the plants, the greatest height being observed in n and k with 200 mg l-1each and concluded that different concentrations of n and k have remarkable effects on the growth. sulphate of potash produced significantly taller plants (60.58 cm) as compared to muriate of potash (59.04 cm). this may be due to the availability of more readily available forms of potassium and sulfur than other sources. length of leaf length of leaf of summer onion was significantly influenced by different sources and levels of potash (table 2). at 70 dat, the highest leaf length (44.09cm) was recorded from 120 kg k ha-1 from k2so4 source and the lowest plant height (34.10cm) from control (0 kgk ha-1 ). similar effects were also observed at 30, 50 and 90 dat. the rate 120 kg k ha-1 from k2so4 showed the best performance which might be due to the availability of the optimum source and level of potassium than other treatments. pettigrew (2008) reported that potassium deficiency can lead to a reduction in the size of individual leaves. number of leaves plant-1 table 2 shows significant differences among the different treatments. at 70 dat, the maximum number of leaves per plant (7.58) was recorded from 120 kg k ha-1 from k2so4 source and the lowest (5.52) from control. similar effect was also recorded at 30, 50 and 90 dat. the rate 120 kg k ha-1 from k2so4 showed the best performance compare to mop application. similarly pettigrew (2008) reported that potassium deficiency can lead to a reduction in both the number of leaves and the size of individual leaves. 40 naher et al. table 2. effect of different sources and levels of potash on yield components of summer onion treatment 30 dat* 50 dat 70 dat 90 dat plant height (cm) length of leaf (cm) number of leaves per plant plant height (cm) length of leaf (cm) number of leaves per plant plant height (cm) length of leaf (cm) number of leaves per plant plant height (cm) length of leaf (cm) number of leaves per plant t1: 0 kg k ha-1 21.32f 16.11f 3.02g 28.62f 22.52g 4.11e 39.85g 34.10f 5.52g 35.66e 30.65g 4.31f t2: 60 kg kha-1 from kcl 23.88e 18.38e 3.28f 30.75e 24.44f 4.66de 42.56f 37.45e 6.05f 38.45d 33.29f 4.55e t3: 120 kg kha-1 from kcl 33.52b 27.88c 4.38d 35.87d 29.71d 5.55cd 45.52d 41.22d 6.55d 41.44c 36.07d 5.22c t4: 180 kg kha-1 from kcl 32.44c 26.96c 4.48c 36.96c 30.88c 5.65c 46.78c 42.35c 6.78c 42.51c 37.11c 5.29b t5: 60 kg kha-1 from k2so4 25.88d 21.67d 3.88e 32.25e 26.67e 5.18d 44.29e 39.38de 6.41e 39.28d 35.35e 4.80d t6: 120 kg kha-1 from k2so4 36.35a 31.01a 5.71a 39.85a 35.88a 6.68a 50.78a 44.09a 7.58a 47.01a 39.89a 5.88a t7: 180 kg kha-1 from k2so4 36.24a 29.87b 5.30b 37.12b 33.66b 6.39b 48.11b 41.88b 7.08b 45.15b 36.01b 5.37b cv (%) 5.6 4.8 3.6 4.72 4.8 5.02 3.8 3.6 4.65 3.88 3.96 4.56 means having common letters are not significantly different at 5% level of significance as per dmrt * dat= days after planting 41 productivity of summer onion to different sources and levels of potash plant disease incidence (%) there were significant differences among the different potash sources and various levels of potash treatment combinations. the fig. 1 shows that the maximum disease incidence (65.67%) was recorded in the control followed by 60 kg k ha-1 from kcl (62.28%)., while the minimum (49.22.17%) in 180 kg k ha-1 from k2so4 source followed by 52.88 and 51.55 % in 60 and 120 kg k ha-1 from k2so4 source, respectively. mandal et al. (2008) reported that application of 40 kg k ha-1 reduced percent disease index (pdi) by more than 10% compared with 0 kgkha-1. muriate of potash treated plot comparatively produced significantly higher disease incidence as compared to sulpfate of potash. the presence of the sulfur element in the potassium sulphate, may have increased the disease tolerance characters in the plants. fig. 1 effect of different sources and levels of potash on disease incidence (%) in summer onion bulb characters the number of harvested bulbs per square meter, bulb diameter and average bulb weight of summer onion were statistically significant (table 3). the highest length of bulb (4.21 cm) was observed from 120 kg k ha-1 of k2so4 and the lowest length of bulb (2.36 cm) by 0 kg k ha-1. the highest diameter of bulb (4.25 cm) was recorded from 120 kg k ha-1 of k2so4 and the lowest (2.78 cm) from the control. the maximum bulb weight (52.14 g) was recorded from the treatment combination with 120 kg ha-1 potassium from k2so4 and the lowest bulb weight (14.01 g) from basal application of 0 kg kha-1. the highest number of bulbs m-2 (50.00) was recorded from 120 kg ha-1 potassium from k2so4 and the lower number (41.00) from potassium control treated plot. yield of bulbs there were significant differences among the different potash sources and various levels of potash. the maximum bulbs yield (14.33 t ha-1) was recorded with potash at 120 kg ha-1of k2so4 followed by 13.95 t ha-1 with 180 kg kha-1 from k2so4 (figure 2). the bulb yield increase with the increasing level of k upto 120 kg ha-1. it indicates that application of 120 kg k ha-1 from k2so4 at vegetative as well as bulb formation stage was much better than the other levels of k. the minimum bulb yield (6.92 tha-1) was recorded in control plot, followed by 10.44 t ha-1 with 60 kg k ha-1 from kcl. according to nabi et al., (2010) sulphate of potash treated crop produced higher yield as compared to mop. 0 10 20 30 40 50 60 70 0 kg k/ha 60 kg k/ha 120kg k/ha 180kg k/ha d is e a se in ci d e n ce ( % ) levels of potash mop source k2so4 source 42 naher et al. table 3. effect of different sources and levels of potash on yield contributing characters of summer onion treatment length of bulb (cm) diameter of bulb (cm) wt. of single bulb (g) no. of bulb m-2 bulb yield (t ha-1) t1: 0 kg k ha-1 2.36e 2.78e 14.01g 41d 6.92f t2: 60 kg k ha-1 from kcl 3.51d 3.55d 26.06f 44c 10.44e t3: 120 kg k ha-1 from kcl 4.07ab 4.11a 47.88b 47b 13.68ab t4: 180 kg k ha-1 from kcl 4.01b 4.06b 44.56d 45c 12.98c t5: 60 kg k ha-1 from k2so4 3.54c 3.60c 29.78e 46b 11.41d t6: 120 kg k ha-1 from k2so4 4.21a 4.25a 52.14a 50a 14.33a t7: 180 kg k ha-1 from k2so4 3.98b 4.02b 45.22c 49ab 13.95b cv (%) 3.75 4.32 3.66 5.32 4.88 means having common letters are not significantly different at 5% level of significance conclusion on the basis of results, it was clearly showed that application of 120 kg k ha-1 from k2so4 along with a blanket dose of n100p50s20b1.5zn4 kg ha-1 and 5 ton cowdung ha-1 appeared as optimum dose for maximizing the bulb yield of summer onion of var. baripiaz-3 in aez-25 of level barind tract, bangladesh. references bbs (bangladesh bureau of statistics), 2015. statistics division, ministry of planning, govt. of the people’s republic of bangladesh. dhaka. pp: 140. fao (food and agriculturalorganization), 2013.(http://faostat.fao.org/site/339/default.aspx). (electronic resource). accssed: 2016-11-16). food and agricultural organization of the united nations, rome, italy. gomez, k. a. and a. a. gomez, 1984. statistical procedure for agricultural research (2 edn.). john willey and sons, singapore. pp: 28-192. hassanpouraghdam, m. b., s. j. tabatabaie, h. nazemiyeh and a. aflatunu, 2008. n and k nutrition levels affect growth and essential oil content of costmary ( tanacetum balsamita l.). j. food, agr. & environ, 6(2): 150-154. islam, m. a., a. t. m. shamsuddoha, m. s. i. bhuiyan and m. hasanuzzaman, 2008. response of summer onion to potash and its application methods. american-eurasian journal of agronomy 1 (1): 10-15. nasreen, s. and a. k. m. hossain, 2000. influence of chemical fertilizers and organic manure on the growth and yield of onion. bangladesh j. agric. res., 25(2): 221-231. nabi, g., a. rab, s. j. abbas, farhatullah, f. munsif and i. h. shah, 2010. influence of different levels of potash on the quantity, quality and storage life of onion bulbs. pak. j. bot., 42(3): 2151-2163. http://faostat.fao.org/site/339/default.aspx 43 productivity of summer onion to different sources and levels of potash pettigrew, w. t., 2008. potassium influences on yield and quality production for maize, wheat, soybean and cotton (electronic resource). physiologia plantarum, 133(4): 670-681. razzaque, a. h. m., m. i. ali and a. k. m. habibullah, 1990. response of boro rice to potassium application in two soils of bangladesh. bangladesh j. soil sci., 21(1): 26-29. sangakara, u.r. and e.r. piyadasa, 1993. influence of potassium on bulb characteristics of shallot. intl. symp. on alliums for the tropics, bangkok, 15-19 feb. 1993. pp: 54. ullah, m.m., 2003. nutrien management in summer onion. ph.d. thesis. dept. of soil science. bangabandhu sheikh mujibur rahman agric. univ., pp: 150. microsoft word 6. baj-291_revised bangladesh agron. j. 2018, 21(1): 61-70 sensitivity of annual weeds against metolachlor+ bensulfuron-methyl herbicide in transplanted rice m. k. a. bhuiyan*, m. m. mahbub and m. z. i. baki agronomy division, bangladesh rice research institute (brri), gazipur, bangladesh *corresponding author, e-mail: bhuiyan072003@yahoo.com (received: 12 december 2017, accepted: 16 september 2018) keywords: metolachlor + bensulfuron methyl, transplanted rice, annual weed, weed control abstract field trials were conducted at bangladesh rice research institute (brri), gazipur during aman, 2014 and boro, 2014-15 to evaluate the efficacy of metolachlor + bensulfuron methyl 20% wp on weed suppression of transplanted rice. metolachlor + bensulfuron methyl 20% wp @ 150, 190 and 230 g ha-1 were applied and pyrazosulfuran ethyl @ 125 g ha-1, weed free and unweeded control were the treatment variables. visual observations indicated that this herbicide possesses high selectivity and not toxic to rice plants. the results revealed that the major weed flora associated with the transplanted rice was mainly comprised of two grasses, two sedges and three broadleaf in aman and two grasses, two sedges and two broadleaf in boro season. the most dominant weeds were cyperus difformis, echinochloa crus-galli, scirpus maritimus and monochoria vaginalis in both the growing seasons. application of metolachlor + bensulfuron methyl 20% wp @ 190 g ha-1 was most effective to suppress weeds in both the seasons resulting in increased grain yield more than 40% as compared to unweeded control. therefore, metolachlor + bensulfuron methyl 20% wp@ 190 g ha-1applied at one to two leaf stage of weed effectively controls the weed infestation in transplanted rice. introduction rice is a staple food of bangladesh. about 160 million peoples in bangladesh depend on rice as main food and about 75 percent of agricultural land use to grow rice. the average yield of rice in bangladesh is 4.5 t ha-1 (brri, 2016). bangladesh needs to feed 215.4 million people in 2050 (kabir et al., 2015). in bangladesh weed infestation reduces rice grain yield by 70-80% in aus rice, 30-40% in transplanted aman rice, 22-36% for modern boro rice cultivars and 80-82% in direct wet seeded rice (bhuiyan, 2016; brri, 2006; mamun, 1990). according to willocquet et al., (1998) and bari, (2010) that yield losses due to the infestation of weeds are greater than the combined losses caused by insect, and diseases in rice. weeds not only cause huge reductions in rice yields but also increase the cost of cultivation, reduce input efficiency, interfere with agricultural operations, impair quality, act as alternate hosts for several insect pests, diseases, they affect the aesthetic look of the ecosystem as well as native biodiversity, affect human and cattle health (bhuiyan et al., 2017). weeds compete for nutrient, space, sunlight and moisture with rice resulting in crop yield loss (sunyob et al., 2015). weed management in rice production is a major constraint and expensive. since hand weeding and other weed control methods are labour intensive and complicated, chemicals are the obvious and cost-efficient weed control practices. chemical weed control has become popular in bangladesh mainly due to the scarcity of labour during peak growing season, and lower weeding cost. now a days the use of herbicides is gaining popularity in rice weed control due to their rapid effects and less cost involvement compared to traditional methods of weeding. pre and post emergence herbicides such as butachlor, pretilachlor, oxadiazone, pyrazosulfuron ethyl, ethoxysulfuron 62 bhuiyan et al. alone or supplemented with one hand weeding have been found to be useful for weed management in transplanted paddy. use of single herbicide might be effective for only sedges or only grass or broadleaf weeds. metolachlor + bensulfuran methyl has been recently developed for post emergence control of weeds in the rice field. so, there is a need to develop environment friendly molecules of newer chemistries with a different mode of action. the present study was, therefore, planned to evaluate the efficacy of metolachlor + bensulfuran methyl for rice weed suppression and find out an appropriate dose of the herbicide and its impacts on transplanted rice. materials and methods the experiments were conducted at the bangladesh rice research institute, gazipur, situated at 23059´33´´ n and 90024´19´´ e at an elevation of 8.4 m from the mean sea level, and is characterized by sub-tropical climate during aman, 2014 and boro, 2014-2015 seasons. the soil of the experimental site was non-calcareous dark grey floodplain with ph around 6.2 and low in organic matter (1.2%). the experiment was carried out with six (6) treatments viz. t1= metolachlor + bensulfuran methyl 20% wp@ 150gha-1 (7.5 g a.i. ha-1), t2= metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1(9.5 g a.i. ha-1), t3= metolachlor + bensulfuran methyl 20% wp @ 230 gha-1(11.5 g a.i. ha-1), t4= pyrazosulfuran ethyl @ 125 g ha-1(12.5 g a.i. ha-1), t5= weed free by hand weeding, and t6=control (unweeded). all treatments were laid out in a randomized complete block design with three replications. twenty-five days of brri dhan49 for aman, and thirty-five days old seedlings of brri dhan28 for boro were transplanted at 20 x 20 cm spacing with 2 seedlings hill-1. fertilizers were applied as aman: n:p:k:s= 69:10:41:11 kg ha-1 and boro; n:p:k:s= 120:19:60:24 kg ha-1 (brri, 2013). all herbicides were sprayed at 1 to 2 leaf stage of weed (7 dat in aman and 12dat in boro) with the help of a knapsack sprayer. in weed free treatment, the plots were kept weed free up to 50 dat by hand weeding. metolachlor + bensulfuran methyl herbicide is innovative in bangladesh and its phytotoxicity needs to be evaluated on rice crop. the phytotoxicity of the herbicide to rice plants was determined by visual observations (yellowing leaves, burring leaf tips, stunting growth, etc.). the degree of toxicity on rice plant was measured by the following scale used by irri (1965). rating visual symptom effect 1 no effect no toxicity 2 yellowing leaves slightly toxicity 3 yellowing leaves and stunting moderate toxicity 4 burning leaves and leaf tips toxicity 5 burning plant, plant kill highly toxicity the rating of toxicity was done within 7 days after application of herbicides. it was observed three times at 3, 5 and 7 days after application of herbicide and the mean rate was calculated from 10 sample plants of a unit plot. data on weed density and dry weight were taken from each plot on 40 dat. the weeds were identified species-wise. dry weights of weeds were taken by drying them in electric oven at 600 c for 72 hours followed by weighing by digital balance. relative weed density (rwd), relative weed biomass (rwb), the sum dominance ratio (sdr) and weed control efficiency (wce) of different weed control treatments were calculated with the following formulas (janiya and moody, 1989; rao ,1985): rwd = density of individual weed species in the community total density of all weed species in the community × 100 sensitivity of annual weeds against metolachlor 63 rwb = dry weight of a given oven dried weed species dry weight of all oven dried weed species × 100 sdr = rwd(%) + rwb(%) 2 wce(%) = ୈ୰୷ ୵ୣ୧୥୦୲ ୭୤ ୵ୣୣୢୱ ୧୬ ୵ୣୣୢ୷ ୡ୦ୣୡ୩ ୮୪୭୲ୱିୈ୰୷ ୵ୣ୧୥୦୲ ୭୤ ୵ୣୣୢୱ ୧୬ ୲୰ୣୟ୲ୣୢ ୮୪୭୲ୱ ୈ୰୷ ୵ୣ୧୥୦୲ ୭୤ ୵ୣୣୢୱ ୧୬ ୵ୣୣୢ୷ ୡ୦ୣୡ୩ ୮୪୭୲ୱ ×100 data on panicle m-2, grains panicle-1, sterility and grain yield were collected. yield attributes and yield data were analyzed with star 2.0.1 software for analysis of variance and graphical presentation. results and discussion phytotoxicity of herbicides on rice plant the degree of toxicity of the herbicide to rice plants and the symptoms produced on the plant are presented in table 1. it is observed that metolachlor + bensulfuran methyl 20% wp@ 150 g ha-1 showed no toxicity, and metolachlor + bensulfuran methyl 20% wp@ 190 g ha-1 showed slight yellowing of leaves while metolachlor + bensulfuran methyl 20% wp@ 230 g ha-1 showed temporary yellowing of leaves. results showed that phytotoxicity symptoms were not more prominent for using this herbicide. phytotoxicity of rice plant found by combined herbicide is less which is like the findings of bhuiyan et al. (2010). table 1. rating of herbicide toxicity on rice plant under different treatments in field condition treatments rating symptom observed in rice field aman boro metolachlor + bensulfuranmethyl 20% wp @ 150 gha-1 (7.5 g a.i. ha-1) 1.10 1.10 no toxicity metolachlor + bensulfuran methyl 20% wp @ 190 gha-1 (9.5 g a.i. ha-1) 1.14 1.17 sometimes slight yellowing of leaves metolachlor + bensulfuran methyl 20% wp @ 230 gha-1(11.5 g a.i. ha-1) 1.90 1.85 slight yellowing of leaves which required 5-7 days to recover pyrazosulfuran ethyl @125 gha-1 (12.5 g a.i. ha-1) 1.12 1.10 no toxicity weed infestation aman season the experimental field was infested with eight different types of weed species belonging to different families of poaceae, cyperaceae, pontederiaceae, marsileaceae, sphenocleaceae and asteraceae. the relative density of these weed species was also different (table 2).among the infesting weeds, twowere grasses, two sedges, and four broadleaf. the weed species belonging to the families of broadleaf were: monochoria vaginalis, marsilea minuta, sphenoclea zeylanicaand eclipta alba; grasses were: echinochloa crus-galli, cynodon dactylon, and sedges were cyperus difformis and scirpus maritimus. among the weed species maximum relative weed density (rwd) was observed for cyperus difformis (31.24%) followed by echinochloa 64 bhuiyan et al. crus-galli (30.40%) but the highest relative weed biomass (rwb) observed for e. crus-galli (33.75%) followed by c. difformis (33%). eclipta albawas the minor weed with 3 and 4 rwd and rwb, respectively. it was also observed that broad leaved were less dominating weed species. priya et al., 2017 revealed that application of herbicide combination, bispyribac sodium + metamifop 14% se at 70 g ha-1 recorded significantly lower total weed density and and higher weed control efficiency. boro season the number of infesting weed species was slightly different in boro than aman. these weed flora were ecologically categorized into two broad leaved species, two sedge and two grasses (table 3). the major weed was c. difformis which (rwd) and (rwb) was 32.50% and 34.07%, respectively. the second top weed was e. crus-galli which rwd was 31.48% and (rwb) was 33.76%. so, in boroseason broadleaf weeds were less dominating than aman season. combination of trisulfuron + pretilachlor effectively control echinochola sp. and cyperus sp. which found by puniya et al., 2007. table 2. weed composition, relative weed density (rwd), and relative weed biomass (rwb) in aman, at gazipur name family type rwd (%) rwb (%) cynodon dactylon poaceae grass 7.65 9.63 echinochloa crus-galli poaceae grass 30.40 32.75 cyperus difformis cyperaceae sedge 31.24 32.45 scirpus maritimus cyperaceae sedge 24.76 23.92 monochoria vaginalis pontederiaceae broadleaf 22.28 27.29 marsilea minuta marsileaceae broadleaf 11.47 12.64 sphenoclea zeylanica sphenocleaceae broadleaf 3.81 2.58 eclipta alba asteraceae broadleaf 2.84 3.45 table 3. weed composition, relative weed density (rwd), and relative weed biomass (rwb) in boro, at brri, gazipur name family type rwd (%) rwb (%) cynodon dactylon poaceae grass 10.76 9.21 echinochloa crus-galli poaceae grass 31.48 33.76 cyperus difformis cyperaceae sedge 32.50 34.07 scirpus maritimus cyperaceae sedge 28.16 27.63 monochoria vaginalis pontederiaceae broadleaf 21.42 26.74 marsilea minuta marsileaceae broadleaf 10.90 12.65 weed ranking the summed dominance ratio (sdr) is more informative than any single measure in reflecting the contribution of a species in the community. the most dominant weeds in aman seasonwere c. difformis, e. crus-galli, s. maritimus and m. vaginalis (fig. 1). cyperus difformis, echinochloa crus-galli, scirpus maritimus and monochoria vaginalis were also the most dominant weeds in boro season. mamun et al., 2011 showed that sdr of a weed against the same herbicide is similar in different seasons. sensitivity of annual weeds against metolachlor 65 fig.1. summed dominance ratio (sdr) of weed species in transplanted rice weed control efficiency (wce) lower weed biomass as well as higher weed control efficiency in all the growing seasons exhibited by metolachlor + bensulfuran methyl. weed control efficiency improved with increases of herbicide dose irrespective of weed species. treatment, t1 controls all the weeds less than 80% due to a lower dose of application, whereas t2, t3 and t4 (check) control e. crusgalli, c. difformis, s. maritimus and m. vaginalis more than 80% in aman season (table 4). the trend of weed control efficiency in boro, 2014-15 was almost similar to aman, 2014. treatment t2, t3 and t4controls e. crus-galli, c. difformis, s. maritimus and m. vaginalis more than 80% (table 5) in boro season. it was evident from the study that the post emergence herbicide metolachlor + bensulfuran methyl @ 190 gha-1 and 230 g ha-1 was effective for controlling weed than other doses of that herbicide. lodhi et al., 2017 reported that application of bensulfuron methyl + pretilachlor control weeds more than 80% in transplanted rice in india. table 4. effect of metolachlor + bensulfuran methylon weed control efficiency in transplanted rice in aman at brri, gazipur name of weeds weed control efficiency (%) t1 t2 t3 t4 cynodon dactylon 40.54 52.30 51.26 45.80 echinochloa crus-galli 62.74 81.36 83.25 84.61 cyperus difformis 68.52 83.20 85.67 81.54 scripus maritimus 72.49 82.36 86.32 83.72 monochoria vaginalis 68.43 80.71 80.87 80.59 marsilea minuta 51.30 62.80 64.38 69.26 sphenoclea zeylanica 62.14 75.33 68.49 72.65 66 bhuiyan et al. eclipta alba 52.62 60.45 62.92 62.75 t1= metolachlor + bensulfuran methyl 20% wp @ 150 g ha-1, t2= metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1, t3= metolachlor + bensulfuran methyl 20% wp @ 230 g ha-1 and t4= pyrazosulfuran ethyl @ 125 g ha-1 table 5. effect of metolachlor + bensulfuran methylon weed control efficiency in transplanted rice in boro, 2014-15 at brri, gazipur name of weeds weed control efficiency (%) t1 t2 t3 t4 cynodon dactylon 37.94 46.39 48.36 52.45 echinochloa crus-galli 66.34 83.68 84.09 83.35 cyperus difformis 70.45 81.60 85.20 85.60 scripus maritimus 68.25 83.35 84.25 83.68 monochoria vaginalis 63.16 80.65 81.85 83.40 marsilea minuta 45.10 57.70 65.50 59.30 t1= metolachlor + bensulfuran methyl 20% wp @ 150 g ha-1, t2= metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1, t3= metolachlor + bensulfuran methyl 20% wp @ 230 g ha-1 and t4= pyrazosulfuran ethyl @ 125 g ha-1 yield and yield attributes from table 6 it was found that all the treatments significantly increased rice grain yields over unweeded condition. in aman season, the highest grain yield (5.18 t ha-1) was recorded in the weed free treatment which was statistically similar to treatments t2 and t4 (5.05 and 4.98 t ha-1, respectively). minimum grain yield (3.21 t ha-1) was found from brri dhan49 in weedy check plots as compared to weed-free treatment due to high weed density which resulted from a smaller number of panicle m2, grains panicle-1 and high sterility. treatment wise box plot of yield attributes in aman season confirm that most of the yield contributing parameters are showed similar range in t2, t4 (check) and t5 (weed-free) treatments; whereas t6 was outside of the normal range and its data was also in dispersing condition than other treatments due to severe weed infestation (fig. 2). the similar trend of results was observed during the boro season where unweeded control (t6) produced the minimum number of panicles m-2, grains panicle-1 and high sterility which resulting the lowest (3.37 t ha-1) grain yield of brri dhan28. the minimum number of panicles m-2 in the control plot was the result of higher competition for nutrient, space, light and water between crop plants and weeds. maximum grain yield of 5.71 t ha-1 that was recorded with t2treatment could be due to lower weed-crop competition at crop growth stages. in boro season, t2, t4 (check) and t5 (weed-free) treatments are in similar range in boxplot of yield attributes (fig. 3). metolachlor + bensulfuran methyl @ 150, 190, 230 gha-1gave effective control of grass, sedge and broad leaf weeds lead to increased grain yield.herbicide treatments contributed to higher yield performance compared to control in all the growing seasons (bari, 2010). table 6. effect of metolachlor + bensulfuran methyl on the yield attributes and yield of transplanted rice at brri, gazipur treatments panicles m-2 grains panicle-1 sterility (%) grain yield (t ha-1) brri dhan49 brri dhan28 brri dhan49 brri dhan28 brri dhan49 brri dhan28 brri dhan49 brri dhan28 t1 222 264 105 114 17.43 16.03 4.93 5.44 t2 228 281 105 114 16.60 14.87 5.05 5.71 t3 216 258 98 111 18.13 16.33 4.72 5.07 t4 237 283 103 114 17.27 15.27 4.98 5.69 t5 236 287 107 117 16.23 14.60 5.18 5.75 sensitivity of annual weeds against metolachlor 67 t6 186 214 78 93 19.77 19.07 3.21 3.37 cv (%) 8.57 3.12 3.08 4.57 4.24 4.20 2.73 2.45 lsd (0.05) 11.08 14.99 5.57 9.21 1.45 1.22 0.23 0.23 t1= metolachlor + bensulfuran methyl 20% wp @ 150 gha-1, t2= metolachlor + bensulfuran methyl 20% wp @ 190 gha-1, t3= metolachlor + bensulfuran methyl 20% wp @ 230 gha-1, t4= pyrazosulfuran ethyl @ 125gha-1, t5= weed free and t6= unweeded (control) fig. 2. box plot of yield attributes in brri dhan49 at brri, gazipur t1= metolachlor + bensulfuran methyl 20% wp @ 150 g ha-1, t2= metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1, t3= metolachlor + bensulfuran methyl 20% wp @ 230 g ha-1, t4= pyrazosulfuran ethyl @ 125 g ha-1, t5= weed free and t6= unweed (control) 68 bhuiyan et al. fig. 3. box plot of yield attributes in brri dhan28 at brri, gazipur t1= metolachlor + bensulfuran methyl 20% wp @ 150 g ha-1, t2= metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1, t3= metolachlor + bensulfuran methyl 20% wp @ 230 g ha-1, t4= pyrazosulfuran ethyl @ 125 g ha-1, t5= weed free and t6= unweed (control) sensitivity of annual weeds against metolachlor 69 conclusion results reveal that yield and yield attributes, and weed dynamics were greatly influenced by different weed management practices. metolachlor + bensulfuran methyl 20% wp @ 230 g ha-1 showed better weed control efficiency although it has slight phytotoxicity. on the other hand, metolachlor + bensulfuran methyl 20% wp @ 190 g ha-1 applied at 1 to 2 leaf stage would be more effective for controlling annual weeds in transplanted rice. references bari, m. n. 2010. effects of herbicides on weed suppression and rice yield in transplanted wetland rice. pakistan j. weed sci. res. 16(4): 349-361. bbs. 1991. statistical yearbook of 1990. bangladesh bureau of statistics, ministry of planning, dhaka. bhuiyan, m. k. a., m. m. mahbub, z. i baki and l. nahar. 2017. sensitivity of annual weeds against sulfentrazone 48 sc herbicide in rice cultivation. bangladesh rice j. 21 (1) : 6776 bhuiyan, m. k. a. 2016.effect of resource conservation technologies and weed management on nitrogen use efficiency, growth and yield of rice. (phd thesis), bau, mymensingh. bhuiyan, m. k. a. and g. j. u. ahmad. 2010. performance of mefenaset + bensulfuron methyl 53%wp against weed suppression in transplanted paddy. pakistan j. weed sci. res. 16 (2):181-187. brri (bangladesh rice research institute). 2006. weed identification and management in rice. bangladesh rice research institute, joydebpur, gazipur, bangladesh. brri (bangladesh rice research institute). 2013. adhunik dhaner chas (in bengali). bangladesh rice research institute, joydebpur, gazipur, bangladesh. brri (bangladesh rice research institute). 2016. adhunik dhaner chas (in bengali). bangladesh rice research institute, joydebpur, gazipur, bangladesh. irri (international rice research institute). 1965. annual report for 1963. irri, los banos, philippines, pp.224-231. janiya, j. d. and k. moody. 1989. weed populations in transplanted and wet-seeded rice as affected by weed control methods. trop. pest manag.35(1) 8 – 11. jayadeva, h. m. 2010. bioefficacy of post emergent herbicides in weed management of transplanted rice (oryza sativa l.). j. crop weed. 6(2): 63-66. kabir, m.s., m.u. salam, a. chowdhury, n. m. f. rahman, k. m. iftekharuddaula, m. s rahman, m. h rashid, s. s dipti, a. islam, m. a latif, a. k. m. s. islam, m. m. hossain, b. nessa, t. h. ansari, m. a. ali, j. k. biswas. 2015. rice vision for bangladesh: 2050 and beyond. bangladesh rice j.19(2): 1-18 lodhi, r., a. rawat, a. k. jha, j. dubey.2017. efficacy of bensulfuron methyl + pretilachlor against weeds in transplanted rice. global j. bio-sci. biotechnol. 6 (2): 285-288. mamun, m. a. a., a. j. mridha, a. akter, a. parvez. 2011. bio-efficacy of acetochlor 50% ec against weed suppression in transplanted rice ecosystem. j. environ. sci. nat. resour. 4(2):73 –77. mamun, a.a. 1990. weeds and their control: a review of weed research in bangladesh. agricultural and rural development in bangladesh. japan intl. co-operation agency. dhaka, bangladesh. jsard. pub. no. 19. pp. 45-72 70 bhuiyan et al. priya, r. s., c. chinnusamy, p. murali arthanari and p. janaki. 2017. weed control in direct seeded rice using new herbicide combination under indian tropical condition. british j. appl. sci. technol. 21(5): 1-14. puniya, r., p.c. pandey and p. s. bisht. 2007. performance of trisulfuron, trisulfuron+ pretilachlor and bensulfuron-methyl in transplanted rice (oryza sativa l.). indian j. weed sci.39 (1 & 2): 120-122. rao, a. n. 1985: weed vegetation analysis. lecture presented to participants attending the weed science workshop, irri, los baños, philippines. sunyob, n. b., a. s. juraimi, m. a. hakim, a. man, a. selamat and m. a. alam. 2015. competitive ability of some selected rice varieties against weed under aerobic condition. intl. j. agric. biol. 17: 61-70. willocquet l, savary 5, fernandel l, elazegui f, teng p. 1998. simulation of yield losses caused by rice diseases, insects, and weeds in tropical asia irri discussion paper series no. 34. manila (philippines): int. rice res. inst. p.62. bangladesh agron. j. 2019, 22 (1): 105-113 functional relationship between grain yield and spikes per square meter of wheat as influenced by seed rate under late sown condition m.a.k. mian*, a.a. begum and r.r. saha agronomy division, bari, gazipur 1701 corresponding e-mail: mianmd.abulkhayer@yahoo.com (received: 29 august 2019, accepted: 16 october 2019) keywords: functional model, grain yield, spikes/m2, wheat, late sown abstract an experiment was conducted at agronomy research field of bangladesh agricultural research institute, gazipur for five consecutive years (20142015 to 2018-2019) to establish a functional relationship between grain yield and spikes/m2 of wheat at late sown condition. variation of spikes/m2 was created by five seed rates (90, 120, 150, 180 and 210 kg/ha). pooled average value of spikes / m2 was observed the highest (479-506) in 180-210 kg seed /ha. from the structural treatment, the highest grain yield (pooled average of 3876-4153 kg/ha ranged 32955028 kg/ha) of wheat was produced in the seed rate of 150-180 kg/ha. the estimated optimum seed rate was found 162.29 kg/ha with the estimated grain yield 3989 kg/ha of wheat at late sown condition through the developed function model of y=485.91+43.17x-0.133x2 (r2=0.87). again, the estimate optimum spikes/m2 was noticed 423 when the estimated grain yield of wheat was 4135 kg/ha at late sown condition through the developed functional model of y=-2837+32.98x0.039x2 (r2=0.83). the grain yield would be increased about 13% as compared to recommended seed rate (120 kg/ha) of wheat. spikes / m2 had significant positive correlation with seed rate (r=0.79 at p=0.05) of wheat. relationship between observed grain yield and predicted grain yield (when relationship between spikes/m2 and grain yield) showed a good consistency (y=1.0006x, r2=0.94 and r = 0.97 at p<0.01). from the results of the study it is concluded that 162 kg/ha of seed rate and 423 spikes / m2 would be optimum for maximum yield) 4135 gk/ah) of wheat at late sown condition. introduction wheat is an important cereal food grain after rice in bangladesh. wheat cultivation increased (4.29 times) after independence of bangladesh (1971) due to development of high yielding varieties along with improved production technology (bari, 2011; bari, 2017; ais, 2018). in bangladesh, area coverage of wheat is 428800 hectares with an annual production of 1423600 tons (ais, 2018). optimum sowing time of wheat is 15 november to 30 november in bangladesh (bari, 2017). the majority farmers usually grow wheat in the same land after harvesting of t. aman rice and thus, sowing of wheat is often delayed (barc, 2013). sowing of wheat in bangladesh may extend upto 20 december depending on the weather, topography and harvesting of the preceding rice crop (barc, 2013). grain yield of wheat is reduced @ 82-87 kg/ha/day (32-36%) after 30 november sowing (begum and mian, 2019). spikes/m2 is a major yield component which has a significant effect on the grain yield of wheat (kadumet al., 2019). the increase of spikes/m2 increased the grain yield of 112 mian et al. wheat (mian, 2008; shankarraoet al., 2010). spikes/m2 is mainly influenced by seed rate and yield is the function of spikes/m2 of wheat (bolton, 2018; sokoto et al., 2012). more number of tillers as well as more number of spikes/m2 is generally noticed in higher seed rate (bari, 2018; nimat et al., 2013). proper growth environment also enhances tillering as well as spikes/m2 of wheat (mian, 2008; njuguna et al., 2010). again, the excess seed rate would create more competition among the tillers producing lower effective spikes/m2 and grain yield of wheat (seleiman et al., 2016). on the other hand, lower seed rate produces higher number of tillers per plant up to a level if proper growth environment is provided. delayed sowing due to late harvesting of t. amanrice and excess soil moisture in southern part of the country reduce grain yield of wheat (barc, 2013). at late sown condition, crop growth is retarded with reduced tillering of wheat producing lower grain yield. moreover, only main tiller (stem) produces effective spikes but lateral or tender tiller fail to produce effective tiller or spike at late sown condition. in modeling concept scientists are trying to establish relationship between yield and spikes/m2 of wheat for estimating the optimum spikes/m2 for maximum yield (mian et al., 2012; moucheshi et al., 2013; bolton, 2018). therefore, the experiment was undertaken to establish a functional relationship between grain yield and spikes/m2 of wheat and to estimate the optimum spikes / m2 for maximum grain yield at late sown condition. materials and methods an experiment was conducted at agronomy research field of bangladesh agricultural research institute, gazipur to establish a functional relationship between grain yield and spikes / m2 of wheat at late sown condition. the experiment was conducted for five consecutive years of 2014-2015 to 20182019. variation of spikes /m2 was created by five seed rates (90, 120, 150, 180 and 210 kg/ha). the wheat var. bari gom-30 was sown on 15-20 december (late sown condition) in 2014 2019. but the optimum sowing time of wheat is 15-30 november in bangladesh (bari, 2017). the experiment was laid out in a rcb design with four replications. unit plot size was 8 m× 5 m. the crop was fertilized with 100-36-25-20-1.8-1.0 kg/ha of n-p-k-s-zn-b (bari, 2011). all the nutrients including two third of n were applied as basal. rest one third of n was top dressed at cri stage. three irrigations were applied at 20 days after emergence (dae), 60 dae and 80 dae. crop field was weeded at 25 dae by spading. the crop was harvested on 27-31 march in 2014-2019. data on crop yield and yield components of wheat were recorded. there was no blast infection in the experimental field. attempt was made to establish functional relationship between grain yield and spikes /m2 of wheat using the quadratic equation like y= a + bx cx2. optimum seed rate and spikes / m2could be estimated with the following formula from the developed functional model (mian et al., 2012). optimum seed rate and spikes / m2=-b/2c (where b and c are the coefficients). the experiment was repeated for the consecutive five years to get sufficient data for establishing the functional relationship. five years’ data on spikes/m2 and grain yield of wheat from 2014-2015 to 2018-2019 were used to develop functional relationship. some important yield components of wheat were recorded and presented on the basis of year wise and combined analysis (only combined effect). the data was subjected to statistical analysis (year wise and combined) and mean values were compared by lsd (0.05). results and discussion functional relationship of wheat 113 yield component and yield spikes/m2 was significantly influenced by seed rate (table 1). the maximum number of spikes/m2 was produced of 210 kg seed /ha (533) followed 180 kg seed / ha (505) while the lowest in 90 kg seed /ha (395) in 2014-2015. similar trend of spikes / m2 (the highest value ranged 444-573and the lowest value ranged 348-457) was noticed in the subsequent growing season of 20152016 to 2018-2019. the highest pooled value of spikes/m2 was observed in 210 kg seed /ha (506) followed by 180 kg seed /ha (479) while the lowest in 90 kg seed /ha (398) (table 1). the results expressed that increasing seed rate increased spikes/m2gradually. similarly, higher spikes/m2 in higher seed rate (160 kg/ha as compared to 120 kg/ha) was also reported by bari (2018). seed rate had significant effect on grains / spike (table 2). the highest grains/ spike was obtained in 90 kg seed /ha (42) followed by 120 kg seed /ha (41) but the lowest in 210 kg seed /ha (34) in 2014-2015 (table 2). similar trend of grains / spike (the highest value ranged 38-52 and the lowest value ranged 26-39) was noticed in the following growing seasons of 2015-2016 to 2018-2019. the highest pooled value of grains/ spike was noticed in 90 kg seed /ha (43) followed by 120 kg seed /ha (40). on the other hand, the lowest value was found in 210 kg seed /ha (32) (table 2). the results reveal that grains/spike was reduced gradually with the increase of seed rate. higher seed rate possibly exerted inter tiller competition resulting less number of grains/pike. less number of grains/spike in higher seed rate was also reported by seleiman et al. (2016) and bari (2018). the weight of 1000-grain was found the highest in 90 kg seed /ha (45 g) followed by 120 kg seed /ha (44 g) while the lowest in 210 kg seed /ha (39 g) in 2014-2015 (table 3). similar trend of 1000-grain weight (the highest value ranged 42-58 g and the lowest value ranged 32-45 g) was observed in the growing season of 2015-2016 to 2018-2019. pooled value of 1000-grain weight was recorded the highest in 90 kg seed /ha (48 g) followed by 120 kg seed /ha (46 g) giving the lowest in 210 kg seed /ha (38 g) (table 3). higher seed rate possibly exerted inter tiller competition reducing individual grain size and weight as well as lower 1000-grain weight. reduced 1000-grain weight of wheat at higher seed rate (160 kg/ha) was also reported by seleiman et al. (2016) and bari (2018). the grain yield of wheat was significantly influenced by seed rate (table 4). the highest grain yield (3803-3858 kg/ha) was produced in 150-180 kg seed /ha but the lowest (3652 kg/ha) in 90 kg seed /ha in 2014-2015. on the other hand, the highest grain yield (5028 kg/ha) was observed in 180 kg seed /ha followed by the 210 kg seed /ha (4839 kg/ha) while the lowest (3652 kg/ha) in 90 kg seed /ha in 2015-2016 (table 4). similar trend of grain yield (the highest grain yield ranged 3738-4376 kg/ha and the lowest value ranged 2436-3225 kg/ha) was noticed in the subsequent growing season of 2016-2017 to 2018-2019. pooled grain yield was obtained the highest in 180 kg seed /ha (4153 kg/ha) followed by 150 kg seed /ha (3876 kg/ha) producing the lowest in 90 kg seed /ha (3418 kg/ha) (table 4). grain yield was mainly contributed by spikes/m2. similar results have also been described by other investigators (nemat et al., 2013; sherwan et al., 2015). grain yield increased about 6-14% in 150-180 kg seed /ha as compared to recommended seed rate (120 kg/ha). the results expressed that higher seed rate up to 180 kg/ha increased grain yield, afterwards the grain yield declined as the increase of seed rate (210 kg/ha). higher seed rate (210 kg/ha) might have exerted more inter tiller competition resulting poorer yield component and grain yield of wheat. moreover, higher seed rate leads the crop to lodging producing lower grain yield. higher seed rates (200 kg/ha) resulted in higher lodging of wheat was also reported by (laghari et al., 2011). the results are in agreement with the observation of seleiman et al. (2016). 112 mian et al. table 1. spikes/m2 (no.) of wheat as influenced by seed rate under late sown condition seed rate (kg/ha) 20142015 20152016 20162017 20172018 20182019 pooled 90 395 348 457 383 408 398 120 447 362 480 412 428 426 150 483 389 493 443 468 455 180 505 426 523 464 478 479 210 533 444 573 493 485 506 lsd (0.05) 41 30 34 24 32 33 cv (%) 5.66 4.87 4.33 4.69 4.91 4.89 table 2. grains/spike (no.) of wheat as influenced by seed rate under late sown condition seed rate (kg/ha) 2014-2015 2015-2016 2016-2017 2017-2018 2018-2019 pooled 90 42 52 40 41 38 43 120 41 48 39 37 36 40 150 38 45 38 34 35 38 180 37 44 35 30 31 35 210 34 39 33 28 26 32 lsd(0.05) 2.69 2.45 2.07 3.37 2.96 2.48 cv (%) 4.55 3.49 3.22 4.11 5.79 4.29 table 3. weight of 1000-grain (g) of wheat as influenced by seed rate under late sown condition seed rate (kg/ha) 2014-2015 2015-2016 2016-2017 2017-2018 2018-2019 pooled 90 45 58 43 42 50 48 120 44 57 41 41 49 46 150 43 48 36 38 47 42 180 40 46 34 35 46 40 210 39 43 32 32 45 38 l sd (0.05) 2.89 4.03 3.65 2.05 2.11 2.89 cv (%) 4.46 5.92 4.86 2.54 2.87 4.37 table 4. seed yield (kg/ha) of wheat as influenced by seed rate under late sown condition seed rate (kg/ha) 2014-2015 2015-2016 2016-2017 2017-2018 2018-2019 pooled 90 3652 4520 3225 3187 2436 3418 120 3781 4592 3743 3405 2804 3651 150 3858 4633 4061 3532 3295 3876 180 3803 5028 4376 3738 3822 4153 210 3586 4839 4065 3584 2464 3708 lsd (0.05) 287 378 373 318 313 328 cv (%) 4.98 5.21 6.22 5.93 5.59 5.66 functional relationship functional relationship of wheat 113 functional relationship between seed rate and spikes/m2 indicates that the effect of seed rate on spikes/m2 of wheat can be explained 72% by functional model of y=2.8613x (r2=0.72) (table 5 and fig.1). the coefficient value of 2.8613 indicates that the number of spikes/m2 would be increased @ 2.8613 with the increase of 1 kg/ha of seed rate. spikes/m2 showed significant positive correlation with the seed rate (r=0.79 at p=0.05). functional relationship between seed rate and grain yield of wheat shows that the effect of seed rate on grain yield can be explained 87% by functional model of y=485.91+43.17x-0.133x2 (r2=0.87) (table 5 and fig.2). number of spikes/m2 had a great impact on the grain yield of wheat as described by moucheshi et al. (2013). the optimum seed rate was estimated at 162.29 kg/ha by the functional model of y=485.91+43.17x-0.133x2 (r2=0.87). then the grain yield would be 3989 kg/ha at the estimated seed rate of 162.29 kg/ha. again, functional relationship between spikes/m2 and grain yield of wheat indicates that the effect of spikes/m2 on grain yield can be explained 83% by functional model of y=-2837+32.98x0.039x2 (r2=0.83) (table 5 and fig. 3). the estimated optimum spikes/m2 was found 423 by the functional model of y=-2837+32.98x-0.039x2(r2=0.83). table 5. relationship between different parameters of wheat as influenced by seed rate fig. no. variable functional relationship r2 1. seed rate and spikes/m2 y =2.8613x r² = 0.72 2. seed rate and grain yield y =485.91+43.17x0.133x2 r² = 0.87 3. spike/m2 and grain yield y= -2837+ 32.98 x0.039x2 r² = 0.83 4. observed and predicted grain yield y= 1.0006x r² = 0.94 seed rate and spikes/m2 correlation coefficient r=0.79 at p=0.05 observed grain yield and predicted grain yield correlation coefficient r=0.97 at p<0.01 then the grain yield would be 4135 kg/ha at the estimated spikes/m2 of 423 giving 13% higher grain yield as compared to recommended seed rate (120 kg/ha) of wheat. kadum et al. (2019) reported that 481-492 spikes/m2 gave the highest grain yield (6.46-6.62 t/ha) of wheat. sokoto et al. (2012) also found that spikes/m2 had significant positive correlation with grain yield of wheat. relationship between observed grain yield and predicted grain yield (when relationship between spikes/m2 and grain yield by the functional model of y=2837+32.98x-0.039x2, r2=0.83) showed a good consistency (y=1.0006x, r2=0.94 and r=0.97 at p<0.01) (table 5 and fig. 4). 112 mian et al. fig. 1. functional relationship between seed rate and spikes/m2 of wheat fig. 2. functional relationship between seed rate and grain yield of wheat y =2.8613x r² = 0.72 0 100 200 300 400 500 600 60 90 120 150 180 210 240 s p ik es /m 2 seed rate (kg/ha) y =485.91+43.17x-0.133x2 r² = 0.87 0 1000 2000 3000 4000 5000 6000 60 90 120 150 180 210 240 g ra in y ie ld ( k g /h a) seed rate (kg/ha) functional relationship of wheat 113 fig. 3. functional relationship between spike/m2 and grain yield of wheat fig. 4. relationship between observed and predicted grain yield of wheat (functional model of spike/m2 and grain yield of wheat; y= -2837+ 32.98x-0.039x2, r² = 0.83) conclusion y= -2837+ 32.98 x-0.039x2 r² = 0.83 0 1000 2000 3000 4000 5000 6000 200 300 400 500 600 g ra in y ie ld ( k g /h a) spikes/m2 y= 1.0006x r² = 0.94 r=0.97 0 1000 2000 3000 4000 5000 6000 0 1000 2000 3000 4000 5000 6000 p re d ic te d g ra in y ie ld ( k g /h a ) observed grain yield (kg/ha) 112 mian et al. from the structural treatment, the highest grain yield (pooled of 3876-4153 kg/ha ranged 3295-5028 kg/ha) of wheat was produced with 150-180 kg seed / ha. the estimated optimum seed rate was 162.29 kg/ha when the estimated grain yield was 3989 kg/ha of wheat at late sown condition through the developed function. furthermore, the estimated optimum spikes / m2was 423 with the estimated grain yield of 4135 kg/ha of wheat at late sown condition through the developed function. then the grain yield would be increased about 13% as compared to recommended seed rate (120 kg/ha) of wheat. about 162 kg/ha of seed rate may be recommended for late sown wheat. references ais (argil.information service). 2018. krishi diary (in bangla). department of argil. extension. khamarbari, dhaka1215. pp.14-119. barc (bangladesh agril. res. council). 2013. hand book of agricultural technology. barc. farmgate, dhaka 1215. pp.21-22. bari (bangladesh agril. res. inst.) 2011. krishi projukti hatboi (hand book of agro-technology). bari. gazipur 1701.pp.1-18. bari (bangladesh agril. res. inst.) 2017. krishi projukti hatboi (hand book of agro-technology). bari. gazipur1701. pp. 1-7. bari (bangladesh agril. res. inst.) 2018. adjustment of seed rate for zn enriched wheat variety bari gom-33. in: bari annual report (2017-18). bari. gazipur 1701. pp. 15-16. begum, a.a. and m.a.k. mian. 2019. estimation of temperature co-efficient of wheat for adjusting proper sowing time. in: annual research report (2018-19). agron. div. bari. pp..185-194. bolton, f.e. 2018. field and other agronomic characters of winter wheat cultivars as affected by five seeding rates and three different environmental conditions. a thesis. master of science. agronomic crop science. oregon state university. usa. (https://ir.library.oregonstate.edu/downloads/ft848t13w; visited on 17 june 2018). pp.31-36. kadum, m.n., n.a. mutlag, and a.j. al-khazal. 2019. evaluation of the performance of bread wheat genotypes in central region of iraq by using selection technique. res. j. chem. environ. 23: 17-22. laghari, g. m., f.c. oad, and s. tunio. 2011. growth and yield attributes of wheat at different seed rates. sarhad j. agric. 27(2): 177-183. mian, m.a.k. 2008. performance of maize oriented cropping patterns under different nutrient management. ph.d. dissertation. agronomy div. bangladesh agricultural university, mymensingh. pp.54-59. mian, m.a.k., k.u. ahammad, m.n. islam, n.a. sultana and m.s. alam. 2012. assessing simple functional yield model for mustard-boro ricet.aman rice cropping pattern under nutrient management. bull inst. trop. agr. kyushu univ. 35: 1-9. mian, m.a.k., m.r. islam, j. hossain and and m.a. aziz. 2016. grain growth of wheat under prevailing air temperature. bangladesh agron. j. 19(2): 79-85. mian, m.a.k and a.a. begum. 2018. crop productivity in beel area of bangladesh. project completion report. natp-2, barc. farmgate, dhaka-1215.pp.12-22. moucheshi, a.s., m. pessarakli and b. heidari. 2013. comparing relationship among yield and its related traits in mycorrhizal and nonmicorrhizal functional relationship of wheat 113 inoculated wheat cultivars under different water regimes using multivariate statistics. inter j. agron. 10: 81-95. nemat, a., noureldin and h.s. saudy. 2013. grain yield response index of bread wheat cultivars as influenced by nitrogen levels. ann. agril. sci. 58(2): 147-152. njuguna, m.n., m. munene and h.g. mwangi 2010. effect of seeding rate and nitrogen fertilizer on wheat grain yield in marginal areas of eastern kenya. j. anim. plant sci. 7(2): 834-840. shankarrao, b. s., s. mukherjee, a.k. pal and d.k. de. 2010. estimation of variability for yield parameters in bread wheat (triticum aestivum l.) grown in gangetic west bengal. electron. j. plant breed, 1(4): 764-768. sherwan, i.t., h.a. shang and k.s. ahmad. 2015. response of grain yield and its component to organic matter and removal of some photosynthetic organs of durum wheat in two years of sulaimani-iraq region. intl. j. plant anim. environ. sci. 5(4): 134-140. shewry, p.r. and j.h. sandry. 2015. the contribution of wheat to human diet and health. food energy secur. 4(3): 178-202. seleiman, m.f., m.e. ibrahim, s.m. abdel-al and g.a. zahran. 2016. effect of seed rate on productivity technological and rheological characteristics of bread wheat (triticum aestivum). intl. j. current res. 4: 75-81. sokoto, m.b., i.u. abubakar and a.u. dikko. 2012. correlation analysis of some growth, yield, yield components and grain quality of wheat (triticum aestivum l.). nig. j. basic appl. sci. 20(4): 349-356. microsoft word 4 bangladesh agron. j. 2017, 20(2): 27-36 growth and productivity of short durationgrowth and productivity of short durationgrowth and productivity of short durationgrowth and productivity of short duration aman riceaman riceaman riceaman rice genotypegenotypegenotypegenotype m. s. hasan, a. r. khanm. s. hasan, a. r. khanm. s. hasan, a. r. khanm. s. hasan, a. r. khan****, m. islam and m. m. haque, m. islam and m. m. haque, m. islam and m. m. haque, m. islam and m. m. haque department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur 1706 *corresponding author, e-mail: arifkhanbsmrau@gmail.com (received:received:received:received: 21 april 2017, accepted:accepted:accepted:accepted: 21 december 2017) keykeykeykey words:words:words:words: variety, advanced line, growth, yield, harvest index abstractabstractabstractabstract a field experiment was conducted at the research field of agronomy department of bangabandhu sheikh mujibur rahman agricultural university during aman season of 2014. twenty four day old seedlings were transplanted in the main filed in a randomized complete block design with three replications. the advanced rice line bu9958-40-5-1 was compared with brri dhan56, brri dhan57, binadhan-7 and bu dhan1. results showed that rice var. brri dhan57 matured earlier [81 days after transplanting (dat)] while the advanced line took the maximum days (90 dat) to mature in the field. although the tallest plant (113.80 cm) was observed in brri dhan56 but tiller number (12.22), leaf area index (4.67) and dry matter production (398.69 g m-2) were the highest in advanced line bu-9958-40-5-1. the advanced line produced the highest grain yield (5.98 t ha-1) coupled with the highest biological yield (11.55 t ha-1) but failed to show the highest harvest index. thus it seemed that this line was not much efficient in converting total dry matter into grain which is the ultimate target of crop production. therefore, this result can help physiologists and breeders to determine physiological and morphological features of the advanced line bu-9958-405-1 that contribute the most to increasing dry matter partition into grain. iiiintroductionntroductionntroductionntroduction in bangladesh, rice is main food for about 160 million people where it covers about 80% of total cropped area (bbs, 2013). in aman season, thousands of land races and cultivars are used all over the country. these races are mostly long duration which delay establishment of winter crops and reduce system productivity. therefore, introduction of short duration aman rice is imperative to crop intensification as well as to enhance system productivity. further, short duration aman rice can create opportunity to evolve even four crops in sequence in a year (haque and rashid, 2016). besides, crop intensification and system productivity of yield improvement of short duration aman rice cannot be ignored. yield improvement of aman rice can be done by breeding method with high yielding genotypes and short duration rice characteristics. very recently, department of genetics and plant breeding, bangabandhu sheikh mujibur rahman agricultural university (bsmaru) developed an advanced line (bu-9958-40-5-1) which is short duration, high zinc and iron content, mild aroma and expected to give higher yield than the released short duration varieties. therefore, this line needs further test to compare yield performance with other released short duration rice varieties growing in aman season. keeping these views in mind, the present study was aimed to evaluate yield potential of 28 hasan et al. advanced line (bu-9958-40-5-1) and compare to growth and productivity of different short duration aman rice. mmmmaterialsaterialsaterialsaterials andandandand mmmmethodsethodsethodsethods the experiment was conducted at the agronomy research field of bangabandhu sheikh mujibur rahman agricultural university, gazipur during aman season of 2014. it is located in madhupur tract under agro ecological zone28 at geographic coordinate 24°05' north latitude and 90°16' east longitude with an elevation of 8.4 m above the mean sea level. the soil of the experimental site is silty clay in surface and silty clay loam in sub-surface region. the site is situated in the sub-tropical region characterized by heavy rainfall during monsoon at the months from may to september and scanty rainfall in the rest of the months of the year. the experimental variables consist of four short duration aman rice varieties viz. brri dhan56, brri dhan57, binadhan-7, budhan1 and one advanced line bu-9958-40-5-1. the experiment was laid out in randomized complete block design with three replications. the unit plot size was 5 m × 4 m and spacing was 20 cm × 20 cm. rice seedlings of 24 days old were transplanted on august 17, 2014 with two seedlings per hill on well puddle soil. gap filling was done within two weeks after transplanting. except nitrogen, the crop was fertilized with a blanket dose of fertilizers 60-50-40-20-4 @ n-p-k-s-zn kg ha-1 respectively at the time of final land preparation. nitrogen was applied in the form of urea in two installments as top dressing. first top dressing was done at 15 days after transplanting (dat) and second at 30 dat. two hand weedings were done at 15 and 30 dat to prevent weed infestation. furadan 5 g @ 10 kg ha-1 was applied to control the infestation of stem borer at active filleting stage. after transplanting, sufficient amount of water was maintained in each plot by supplementary irrigation throughout the growing period. standing water was maintained in the field at 2 to 4 cm until hard dough stage was reached. data on different growth parameters, yield components and yield were recorded. plant samples were collected at 10 days interval starting from 15 dat till maturity. at each sampling, three hills were uprooted sequentially from a single row. to avoid border effect, plants were sampled from second and third rows at each sampling time. the above ground plant parts were segmented into different components as leaf, stem, leaf sheath and panicle. leaf areas of sampling were measured by an automatic leaf area meter (aam-8, hayashi dehnko, japan) immediately after sampling. the partitioned plant parts were then dried in an oven at 70oc for 72 hours and weighed. grains and straw obtained from each unit plot were sun dried and weighed. the grain yield and straw yield was converted tot ha-1. data on different parameters were statistically analyzed using procedure described by gomez and gomez (1984) and means were compared using least significant difference by lsd test. rrrresultsesultsesultsesults andandandand ddddiscussioniscussioniscussioniscussion phenological eventsphenological eventsphenological eventsphenological events phenological events differed significantly among the aman rice genotypes (table 1). days to 50% flowering (45) and days to 100% flowering (49) were the least in brri dhan57 and it matured at 81 dat which was statistically similar with brri dhan56. however, days to 50% flowering (57) and days to 100% flowering (61) were the longest in bu-9958-40-5-1 and it matured at 90 dat. other genotypes matured within intermediate times. such variation in phenological events observed among the genotypes might be due to environmental factors as 29 growth and productivity of short duration genotypic well as their genetic make-up. sometimes, quick vegetative growth of plants resulted in early switch over to reproductive phase (reddy, 2004). these findings are conformity with findings of udayakumar (2005). soil plant analysis development (spad) valuessoil plant analysis development (spad) valuessoil plant analysis development (spad) valuessoil plant analysis development (spad) values the spad measures the content of leaf chlorophyll pigment. the spad values differed significantly among the genotypes (table 1). numerically, the lowest spad value (26.62) was recorded from brri dhan57. on the other hand, the advanced line bu-9958-40-5-1 gave the highest spad value (36.74). higher photosynthesis rate in different variety is supported by leaf chlorophyll content in leaf blades (miah et al., 1997). in present study, higher spad value recorded in the advanced line bu-9958-40-5-1 indicated that this genotype possessed higher photosynthetic capacity and dry matter production than other genotypes. table 1. phenological events and spad value of aman rice genotypes genotypes 50% flowering (dat) 100 % flowering (dat) maturity (dat) spad value brri dhan56 49 53 82 29.97 brri dhan57 45 49 81 26.62 binadhan-7 53 58 85 32.70 bu dhan1 57 61 87 35.50 bu-9958-40-5-1 57 61 90 36.74 cv (%) 1.49 1.48 0.77 5.47 lsd (0.05) 1.46 1.58 1.24 3.33 plant height plant height plant height plant height irrespective of genotypes plant height of aman rice increased progressively with the increased growth duration from transplanting to maturity (fig. 1). the plant height also significantly affected among the rice genotypes. results showed that the genotype brri dhan56 produced the tallest plant at all sampling dates and it was the highest (113.80 cm) at harvest. the rice genotype binadhan-7 produced the shortest plant (102.56 cm) which was statistically similar (104.45 cm) to brri dhan57. bu-9958-40-5-1 (107.03 cm) and bu dhan1 (105.98 cm) produced the second highest plant height. this variation in plant height was probably due to the genetically make-up of the genotypes. these results were consistent with those of naha (2007) and kamal (2006). fig. 1. plant height of different aman rice genotypes over the growing period 0 20 40 60 80 100 120 15 25 35 45 55 65 75 harvest p la n t h e ig h t (c m ) p la n t h e ig h t (c m ) p la n t h e ig h t (c m ) p la n t h e ig h t (c m ) days after transplanting brri dhan56 brri dhan57 binadhan-7 bu dhan1 bu-9958-40-5-1 30 hasan et al. number of tillers hillnumber of tillers hillnumber of tillers hillnumber of tillers hill----1111 number of tillers hill-1 was significantly influenced by the rice genotypes (fig. 2). number of tillers hill-1 of aman rice increased over time. the highest number of tillers hill-1 (12.22) was counted in bu-9958-40-5-1 and the lowest tillers hill-1 (8.33) was observed in brri dhan57 at harvest. brri dhan56 had the second highest number (10.67) of tillers hill-1. binadhan-7 and bu dhan1 had the third highest number of tillers hill-1 which was 10.44 and 10.44, respectively. variable effect of variety on number of tillers hill-1 was also reported by guowei et al. (1998) who noticed that total tillers m-2 differed significantly among the varieties in aman season. the variation in number of tillers hill-1 might be due to varietal attributes and genetical characters. fig. 2. number of tillers hill-1 of aman rice genotypes over the growing period leaf area indexleaf area indexleaf area indexleaf area index leaf area index (lai) was significantly influenced by different rice genotypes. the lai increased progressively up to 55 dat but later the curve leaned downwards (fig. 3). such decline in lai might be due to leaf senescence. the highest leaf area index (5.42) was found at 55 dat in bu-9958-40-5-1 and it decreased to 4.67 at harvest. the lowest lai (4.21) was recorded in brri dhan57 which was statistically similar with brri dhan56 at harvesting stage. the second highest lai (4.57) was obtained in bu dhan1 and then lai (4.46) of binadhan-7. this result showed that genotypic variation in lai was confirmed the finding of reddy et al. (1995) who reported that rice genotypes differed markedly in lai and net assimilation rate. dry matter partitioningdry matter partitioningdry matter partitioningdry matter partitioning variation in dry matter production in leaf, leaf sheath, stem and panicle was statistically significant over the rice genotypes (fig. 3). the highest leaf blade, leaf sheath and stem dry matter was obtained from bu-9958-40-5-1 at all the growth stages. the highest panicle (398.69 g m-2) dry weight was also obtained from bu-9958-40-5-1 at all stages. in general, pattern of dry matter partitioning into leaf, stem, leaf sheath and panicle of rice was almost similar across the rice genotypes. dry matter partitioning into leaf, stem and leaf sheath increased up to 55 days after transplanting while panicle dry weight continued to increase till maturity. dry matter partitioning into vegetative organs decreased after 55 days after 0 2 4 6 8 10 12 14 16 18 20 15 25 35 45 55 65 75 harvest t ill e rs p e r h ill t ill e rs p e r h ill t ill e rs p e r h ill t ill e rs p e r h ill days after transplantingdays after transplantingdays after transplantingdays after transplanting brri dhan56 brri dhan57 binadhan-7 bu dhan1 bu-9958-40-5-1 31 growth and productivity of short duration genotypic transplanting which indicated remobilization of assimilates from vegetative parts towards developing grain. several authors (barvestani and pirdashti 2001; ntanos and koutroubus, 2002) showed that two physiological processes are involved in grain growth; utilization of photosynthates through current photosynthesis and remobilization and translocation of assimilates accumulated before anthesis. in present study, it seemed that stem had higher amount of dry matter remobilization than other vegetative organs of rice as reduction of stem reserve was more pronounced. this result was in consistent with the findings of yang et al. (2003) and kumar et al. (2006) and they reported that different rate of remobilization among the rice genotypes were reported to their agronomic and physiological characteristics. (a) (b) (c) (d) (e) (f) fig. 3. pattern of leaf area index (a) and dry matter partitioning to different parts of rice genotypes (b, c, d, e, and f) over the growing period. 0 1 2 3 4 5 6 l e a f a re a i n d e x ( l a i) l e a f a re a i n d e x ( l a i) l e a f a re a i n d e x ( l a i) l e a f a re a i n d e x ( l a i) days after transplantingdays after transplantingdays after transplantingdays after transplanting brri dhan 56 brri dhan 57 bina dhan 7 bu dhan 1 0 200 400 600 800 15 25 35 45 55 65 75 d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m --2 ) 2 ) 2 ) 2 ) days after transplantingdays after transplantingdays after transplantingdays after transplanting brri dhan56brri dhan56brri dhan56brri dhan56 leaf sheath 0 100 200 300 400 500 600 700 15 25 35 45 55 65 75 d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m --2 ) 2 ) 2 ) 2 ) days after transplantingdays after transplantingdays after transplantingdays after transplanting brri dhan57brri dhan57brri dhan57brri dhan57 leaf sheath 0 200 400 600 800 15 25 35 45 55 65 75 d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m --2 ) 2 ) 2 ) 2 ) days after transplantingdays after transplantingdays after transplantingdays after transplanting binadhanbinadhanbinadhanbinadhan----7777 leaf sheath stem panicle 0 200 400 600 800 15 25 35 45 55 65 75 d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m --2 ) 2 ) 2 ) 2 ) days after transplantingdays after transplantingdays after transplantingdays after transplanting bu dhan1bu dhan1bu dhan1bu dhan1 leaf sheath stem panicle 0 200 400 600 800 1000 15 25 35 45 55 65 75 d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m d ry m a tt e r (g m --2 ) 2 ) 2 ) 2 ) days after transplantingdays after transplantingdays after transplantingdays after transplanting bubububu----9958995899589958----40404040----5555----1111 leaf sheath 32 hasan et al. number of panicles number of panicles number of panicles number of panicles mmmm----2222 number of panicles m-2 varied significantly among the rice genotypes. results showed that the maximum panicles m-2 (310.00) was produced by bu-9958-40-5-1 which was statistically similar with binadhan-7 (273.25), bu dhan1 (268.25), and brri dhan56 (265.00). the rice genotype brri dhan57 produced the lowest number of panicles m-2 (215.00) and it was statistically similar with brri dhan56, binadhan-7 and bu dhan1 (table 3). the variation in number of panicles m-2 might be due to genetical characteristics of rice genotypes. miller et al. (1991) observed that panicles m-2 were the most important component of yield and accounted for 89% of the varieties in yield. the genotypic variation in panicles m-2 was also similar to that which noted by shamsuddin et al. (1988) under rainfed condition in aman season. panicle length panicle length panicle length panicle length there was significant variation in panicle length of rice genotypes. the longest (28.40 cm) panicle was obtained from bu-9958-40-5-1 and the lowest (22.94 cm) in brri dhan57 (table 2). alam et al. (2002) also found varietal differences in panicle length of rice where the variety with the longest panicle contributed more spikelets per panicle. thus, like other yield components, panicle length is also considered as important parameter of yield enhancement of rice. table 2. grain yield and yield components of aman rice genotypes genotypes number of panicles m-2 panicle length (cm) grains panicle-1 1000-grain weight (g) grain yield (t ha-1) brri dhan56 265.00 26.36 155.68 22.56 4.12 brri dhan57 215.00 22.94 149.86 16.63 3.43 binadhan-7 273.25 23.74 134.70 22.95 4.60 bu dhan1 268.25 24.53 116.58 26.60 5.14 bu-9958-40-5-1 310.00 28.40 127.17 24.14 5.98 cv (%) 15.48 1.50 9.16 2.19 6.91 lsd (0.05) 3.10 0.71 17.86 0.93 0.61 number of number of number of number of grains grains grains grains paniclepaniclepaniclepanicle----1111 aman rice genotypes differed significantly in respect of number of spikelets panicle-1. table 2 showed that brri dhan56 produced the maximum number of grains panicle-1 (164.83) which was statistically similar with brri dhan57 and bu-9958-40-5-1. the lowest number of grains panicle-1 (117.90) was observed with bu dhan1 which was statistically similar (127.50) to binadhan-7. singh and gangwar (1989) also reported variable number of grains panicle-1 among different rice genotypes. shortage of assimilates may occur either due to limitation of source or deficiencies of any nutrient. varietal differences regarding the number of grains panicle-1 might be due to their genetic constitution that differentiated in photosynthetic assimilate accumulation especially after heading. therefore, there is possibility to increase number of grains panicle-1 by adopting proper agronomic manipulation. 1000100010001000----grain weight or grain weight or grain weight or grain weight or test test test test weightweightweightweight genotypes showed significant variation in 1000grain weight. the highest test weight (26.60 g) was obtained from bu dhan1 and the lowest one (16.63 g) from brri dhan57 (table 2). rice genotype bu-9958-40-5-1 produced the second highest (24.14 g) test weight. although 33 growth and productivity of short duration genotypic 1000grain weight is genetically controlled but it might be changed to some extent due to changes in environmental condition. in the present study, variation in test weight was observed although non-significant variation in test weight of different modern rice varieties was observed by islam et al. (1999). grain yieldgrain yieldgrain yieldgrain yield grain yield varied significantly among the rice genotypes which ranged from 3.43 to 5.98 t ha-1 (table 2). among the genotypes, bu-9958-40-5-1 produced the highest grain yield. which was associated with its better yield components especially number of panicles hill-1. maximum contribution of number of panicles in improving grain yield was also confirmed by having strong correlation of this component with grain yield (fig. 4). on the other hand, brri dhan57 produced the lowest grain yield. such differences in production potential of rice were recorded by naha (2007), mumin (2002) and biswas et al. (1998) who observed variable grain yield among rice varieties. fig. 4. relationship between number of panicles hill-1 and grain yield of aman rice genotypes straw yieldstraw yieldstraw yieldstraw yield data regarding straw yield showed significant variation among the rice genotypes (table 3). it was evident that the maximum straw yield (5.79 t ha-1) was produced by bu dhan1 which was statistically similar to bu-9958-40-5-1 and binadhan-7. brri dhan57 had given the second highest straw yield (4.17 t ha-1) which was statistically identical (3.81) to brri dhan56. these results were consistent with those of khisha (2002) and chowdhury et al.,1995 who also observed significant variation in straw yield among the varieties. biological yieldbiological yieldbiological yieldbiological yield the highest biological yield (11.55 t ha-1) was obtained from bu-9958-40-5-1 which was statistically similar (10.74 t ha-1) with bu dhan1 and binadhan-7. the genotypes which had higher straw and grain yield that in turn increased the biological yield islam et al.,2014. the lowest biological yield (7.61 t ha-1) was obtained from brri dhan57 which was statistically similar (7.93 t ha-1) with brri dhan56. lamberts et al. (2007) also observed similar result and concluded that different varieties of transplant aman rice show variation in biological yield. y= 0.662x 2.399 r² = 0.855 3 3.5 4 4.5 5 5.5 6 6.5 8.00 9.00 10.00 11.00 12.00 13.00 14.00 g ra in y ie ld ( t h a g ra in y ie ld ( t h a g ra in y ie ld ( t h a g ra in y ie ld ( t h a --1 ) 1 ) 1 ) 1 ) number of panicles hillnumber of panicles hillnumber of panicles hillnumber of panicles hill----1111 34 hasan et al. harvest indharvest indharvest indharvest indexexexex rice genotypes exerted significant effect on harvest index (table 3). the maximum harvest index (52.31%) was observed in brri dhan56 which was statistically similar with binadhan-7, bu dhan1 and bu-9958-40-5-1. the lowest (45.63%) was recorded in brri dhan57 which was statistically identical to binadhan-7, bu dhan1 and bu-9958-40-5-1. it is the genetically attributes that showed variation in harvest index of different rice genotypes. tyeb (2012) observed the similar results and concluded that harvest index depends on inherent genetical attributes and the prevailing environmental condition of the growing season. table 3. straw yield, biological yield and harvest index of aman rice genotypes genotypes straw yield (t ha-1) biological yield (t ha-1) harvest index (%) brri dhan56 3.81 7.93 52.31 brri dhan57 4.17 7.61 45.63 binadhan-7 5.26 9.86 46.96 bu dhan1 5.79 10.94 47.28 bu-9958-40-5-1 5.58 11.55 51.80 cv (%) 16.99 11.56 6.86 lsd (0.05) 1.58 2.09 6.30 cccconclusiononclusiononclusiononclusion results of the present study indicated that there was variability in performance of short duration aman rice genotypes. among the rice genotypes, brri dhan57 was earlier (81 dat) while the advanced line bu-9958-40-5-1 took the maximum days (90 dat) to mature. however, the advanced line produced the highest grain yield (5.98 t ha-1) coupled with the highest biological yield (11.55 t ha-1) but failed to show the highest harvest index. thus it seemed that this line was not much efficient in converting total dry matter into grain which is the ultimate target of crop production. therefore, this result can help physiologists and breeders to determine physiological and morphological features of the advanced line bu-9958-40-5-1 that contribute most to increasing dry matter partition into grain. rrrreferenceseferenceseferenceseferences alam, m. z., m. ahmed, m. s. alam, m. e. haque and m. s. hossain. 2002. performance of seedling age and seedling raising technique on yield and yield components of transplanted aman rice. pakistan j. biol. sci. 5: 1214-1216. barvestani, z. t. and h. pirdashty. 2001. dry matter and nitrogen remobilization of rice genotypes under different transplanting dates. proc. 10th australian agron. conf. bbs (bangladesh bureau of statistics). 2013. the statistical yearbook of bangladesh. ministry of planning. govt.people’s republic of bangladesh. biswas, j. k., m. a. hossain, b. c. sarker, m. hansan and m. z. haque. 1998. yield performance of several rice varieties seeded directly as late amancrops. bangladesh j. life sci. 10: 4772. 35 growth and productivity of short duration genotypic chowdhury, s. a., m. a. majib, k. s. haque, m. islam, and m. m. rahman. 1995. effect of variety on yield and nutritive value of rice straw. asian. j. animal sci. 8: 326-335. gomez, k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. john willey and sons. new york, chichester, brisbane, toronto. pp. 97-129. guowei, w., t. loyold, wilson and m. m. anna. 1998. contribution of rice tillers to dry matter accumulation and yield. agron. j. 90: 317-323. haque, m. m. and m. m. rashid. 2016. development of alternative cropping pattern with four crops in sequence in northern bangladesh. paper presented in seminar on transforming agriculture for sustainable development. international agricultural conference, organized by kib, 29-30 sep., 2016, dhaka, bangladesh. islam, m. r., m. s. rahman, m. h. rahman, m. a. awal and s. m. g. hossain.1999. effect of date of transplanting on yield and yield attributes of two advanced mutants of rice on amanseason. bangladesh j. nuclear. agric. 15: 34-40. kamal, m. m. 2006. effect of variety and planting method on the growth and yield of bororice. thesis m.s. in agron., bangladesh agril. univ., mymensingh. pp. 33-35. khisha, k. 2002. an evaluating of madagascar system of rice production in aman season. m.s. thesis. dept. agronomy. bangladesh agril. univ., mymensingh. pp. 90-98. kumar, r., a. k. barawagi, c. ramos, s. t. amarante, a. m. ismail and i. j. wade. 2006. partitioning of dry matter during drought stress in rainfed low land rice. field crops res. 9:1-11. lamberts, l., e. bie., g. e. vandeputte, w. s. veraverbeke, v. derycke and j. a. delcour. 2007. effect of different varieties on growth and development of transplant aman rice. manilla j. agric. sci. 100(4): 1496-1. miah, m. n. h., t. yoshida and y. yomamoto. 1997. effect of nitrogen application during ripening period on photosynthesis and dry matter production and its impact on yield and yield components of semi dwarf indica rice varieties under water culture conditions. soil sci. plant nut. 43: 205-217. miller, b. c., j. e. hill and s. r. roberts. 1991. plant population effects on growth and yield in water needed rice. agron. j. 83:291-297. mumin, m. a. 2002. performance of some amanrice varieties as influenced by planting time. m.s. thesis, dept. agron, bangladesh agril. univ., mymemsingh. pp. 43-44. naha, r. n. 2007. effect of variety and seedling age on the performance of aman rice.thesis, m.s. in agron., bangladesh agril. univ., mymemsingh. pp. 34-54. ntanos, d. a. and s. d. koutroubus. 2002. dry matter and n accumulation for india and japonica rice under mediterranean conditions. field crops res. 74:93-101. reddy, k. g. 2004.varietal performance special requirement of rice under system of rice intensification during kharif season. m. sc. (ag.) thesis, acharya n.g. ranga agric. univ., hyderabad, india. reddy, y., t. g. prashad and m. udayakumar. 1995. relation between leaf area index, specific leaf weight and assimilation rate in rice genotype. madras agril. j. 616-617. 36 hasan et al. shamsuddin, a. m., m. a. islam and a. hossain. 1988. comparative study on the yield and agronomic characters of nine amancultivars of rice in rainfed condition. bangladesh j. agril.sci. 15: 121124. singh, s. and b. gangwar. 1989. comparative studies on production potentials in traditional tall and improved rice cultivars. j. andaman sci. assoc. 5: 81-82. udayakumar. 2005. studies on system of rice intensification (sri) for seed yield and seed quality. m. sc. (ag) thesis, acharya n.g. ranga agric. univ., hyderabad, india. yang, j., j. z. wang, l. liu and q. zhu. 2003. post anthesis water deficits enhance grain filling in two-line hybrid rice. crop sci. 43: 2099-2108. bangladesh agron. j. 2019, 22(2): 25-39 amelioration of salinity tolerance in foxtail millet by applying plant growth regulators d. biswas1, m.a. mannan1*, m.a. karim1 and m.y. miah2 1department of agronomy, 2department of soil science bangabandhu sheikh mujibur rahman agricultural university *corresponding e-mail: mannanbsmrau@yahoo.com (received: 17 december 2019, accepted: 04 may 2020) keywords: improving, salinity tolerance, foxtail millet and plant growth regulators abstract a pot experiment was laid down at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur from november 2018 to march 2019 to improving the salinity tolerance in foxtail millet (bari kaon 1) using different plant growth regulators with different doses. two salinity levels, i) control (0mm nacl) and ii) 80 mmnacl were maintained after 14 days of sowing to harvest. the plant growth regulators i) humic acid (ha): a) @ 5 gl-1 water b) @ 10 gl−1water ii) gibberellic acid (ga3): a) @10 g l-1water b) @20 g l-1water iii) salicylic acid (sa): a) @ 50 g l-1water b) @ 100 g l-1water were sprayed at 7 days interval from salt imposition. the experiment was in a completely randomized design (crd) with three replications. results revealed that plant growth regulators improved the growth and yield performance of foxtail millet under both control and saline conditions. amelioration of salinity tolerance in foxtail millet was well associated with lower proline content, higher chlorophyll content and spad value as well as dry matter production, which facilitated the foxtail millet yield due to application of plant growth regulators. among the plant growth regulators, humic acid (ha) @ 5 g l-1 water was the best treatment to improving the salinity tolerance in foxtail millet under saline condition. introduction salinity affects almost every aspect of the physiology and biochemistry of plants and significantly reduces yield. the major inhibitory effect of salinity on plant growth and yield has been attributed: 1) to osmotic effect,2) ionic toxicity and3) nutritional imbalance leading to a reduction in photosynthetic efficiency and other physiological disorders (ali et al., 2004). generally, the trend and magnitude of adverse changes varied within species, varieties/genotypes according to the level of salinization. salt stress leads to a decreased efficiency of photosynthesis and is known to influence the chlorophyll content of plant leaves (meloni et al., 2003). the decrease of chlorophyll synthesis may be due to a decrease of δ-aminolevulinic acid dehydratase (alad) activity under environmental stress (vajpayee et al., 2000), but there is no clear information on the behavior of this enzyme in leaves under salt stress conditions. proline accumulation is one of the adaptations of plants to salinity. it has also been widely advocated that proline accumulation uses as a parameter of selection for salt stress tolerance (ramanjulu and sudhakar, 2001). foxtail millet has attracted international research attention due to its high stress tolerance, photosynthetic efficiency, nutritional values and health benefits (liu et al., 2011, vetriventhan et al., 2012). the existence of differences in salt tolerance not only amongst different species but also within certain species (munns and tester, 2008) offers an opportunity for identifying and developing salttolerant genotypes. breeding for salinity tolerant in a crop is difficult due to the involvement of several genes controlling the character and lack of sufficient knowledge of the mechanisms controlling salt 26 biswas et al. tolerance (aktita and cabusley, 2003). therefore, the efforts have been made to improving salt tolerant in cultivated crops through exogenous application of different plant growth regulators. humic acid (ha) is believed to have an important role in promotion of plant growth as a biostimulation. it can induce alteration in plant primary and secondary metabolism linked to abiotic stress tolerance, which leads to improved plant growth and increased resistance against abiotic stress (saidimoradi et al., 2019). the mechanism of ha in promoting plant growth is not completely known, but several explanations proposed (nardi et al., 2002) attributed the beneficial effects of ha on plant growth to increasing minerals transport during cell membrane, oxygen uptake, respiration and photosynthesis, nutrients uptake and root and cell elongation. gibberellic acid (ga3) treatment has alleviated the drastic effect of salinity in growth parameters (leaf area, dry weight of grains and photosynthetic pigments) and chemical constituents (carbohydrates, proteins, amino acids and proline content in two wheat cultivars (sohag 3 and giza 168) (shaddad et al., 2013). maggio et al. (2010) reported that ga3 treatment in lens esculentum reduced stomatal resistance and enhanced plant water use at low salinity. salicylic acid (sa) is naturally occurs in plants in very low amounts and participates in the regulation of many physiological processes in the plant such as nutrient uptake, chlorophyll and protein synthesis. hossain et al. (2015) reported that nacl induced reduction in the plant growth and yield of chickpea could be mitigated by exogenous application of plant growth regulators such as sa and ga3 at a low concentration under low salinity stress. the aim of this study is to study the effects of different plant growth regulators to ameliorate salinity tolerance in foxtail millet variety bari kaon-1 (titas). therefore, the objectives of the research work is i) to study the effect of exogenous application of plant growth regulators on some physiological and biochemical parameters related to salinity tolerance in foxtail millet ii) to evaluate the growth and yield associated characters of foxtail millet in response to plant growth regulators under salinity; and iii) to determine the appropriate plant growth regulator and their doses this could effectively ameliorate the adverse effects of salt stress on foxtail millet. materials and methods the pot experiment was conducted under a semi-controlled environmental condition in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur from november 2018 to march 2019. it was located at 24.090 n latitude and 90.260 e longitudes at an elevation of 8.4 m from the mean sea level. the experimental soil was collected before the sowing of seeds. the physical and chemical properties of the soils were sand (40.51%), silt (28.71%), clay (30.78%), ph (6.18), organic carbon (1.45%), total nitrogen (0.712%), available p (7.24 mg p100-1 g dry soil), exchangeable k (0.169 meq 100-1 g dry soil), zn (7.07meq100-1g dry soil) and the texture was sandy loam. the soil of the pot was fertilized uniformly with 0.40, 0.34 and 0.20 g urea, triple superphosphate and muriate of potash corresponding to 100-75-40 kg urea, triple superphosphate and muriate of potash per hectare, respectively (bari, 2000).foxtail millet variety: bari kaon -1 (titas) was used in this experiment. bari kaon -1 was released by the bangladesh agricultural research institute (bari).the experiment was laid out in completely randomized design (crd) with three replications. ten healthy seeds were sown maintaining uniform spacing in each pot on 18 november 2018. light irrigation was given by using the water cane to ensure uniform germination of seeds after sowing. the experiment consisted of the following two treatments: factor a: salinity levels2: i. control (0 mm nacl) ii. 80 mm nacl. factor b: plant growth regulators-3: i) humic acid (ha): a) @ 5 g l-1 water b) @ 10 g l-1water ii) gibberellic acid (ga3): a) @ 10 g l-1waterb) @ 20 g l-1water iii) salicylic acid (sa): a) @ 50 g l-1water b) @ 100 g l-1water. seeds were sown in plastic pots of 24 cm (diameter) × 30 cm (height) in size filled with soil and kept inside plastichouse under natural light. after the seedling establishment, six uniform and healthy plants were allowed to grow in each pot. weeding and pest control measures were taken properly as and when necessary. the salt solution was prepared by adding the required amount of nacl in tap water making 80 mm salinity level. saline treated pots were irrigated by saline solution from 14th days after sowing (das) to maturity as and amelioration of salinity tolerance in foxtail millet 27 when necessary and control pots were irrigated by tap water. different concentration of ha, ga3 and sa were applied once in a week from 20 das to flowering stage. data on plant height, leaf fresh and dry weight were recorded at 20 and 40 days after salt imposition. spad values were measured at 07 days intervals of salt imposition. leaf proline and chlorophyll content were measured at flowering stage. leaf, stem, root and total dry matter weight and yield were recorded at harvest. spad (soil plant analysis development) value was determined from the top fully expanded leaf by a portable chlorophyll meter (minolta spad-502).chlorophyll content was estimated from the fully expanded uppermost leaf samples using the method described by witham et al. (1986).fully expanded uppermost leaf samples were collected and proline extractions were made using the method outlined by bates et al. (1973).leaf fresh and dry weight were recorded at 20 and 40 days after salt imposition. at the maturity stage crop was harvested. after harvest soil was washed out gently by tap water and plants were partitioned into root, stem and leaf. yield and yield contributing characters like panicle weight, seed yield. sodium and potassium in the plant straw were determined after harvest following the method described by (jackson, 1973). the recorded data were statistically analyzed by “cropstat 7.2” software. the treatment means were compared by least significance difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion plant height plant height differences of foxtail millet at vegetative stages indicated that plant height varied due to different plant growth regulators and their doses under saline conditions (figure 1). at 20 days after salt imposition, salinity stress decreased plant height compared to control but different plant growth regulators increased plant height. the highest plant height was recorded 42.77 cm, when sa was applied @ 10 g l-1water, followed by 41.22 cm, 39.60 cm and the lowest was 36.40 cm when ha was applied 5g l-1water, ga3 10 g l-1waterand sa 100g l-1water, respectively after 20 days salt imposition. on the other hand at 40 days after salt imposition salinity also reduced plant height. plant growth regulators increased plant height under the saline condition at 40 days after salt imposition. the highest plant height was recorded 85.85 cm, when ga3 was applied @ 10 g l-1water,followed by 81.23 cm, 75.13 cm and the lowest was 62.57 cm when ga3 was applied 20 g l-1water,sa 50g l1water, and sa 100 g l-1water respectively (figure 1). so it is clear that plant height is affected by salinity and application of growth regulators enhances the salinity tolerance in foxtail millet in respect of plant height. salinity induced reduction in plant height is a common phenomenon and was also reported earlier for different crops, e.g., mungbean (aziz, 2003); mungbean, cowpea and soybean (egeh and zamora, 1992). the reduction in plant height was probably resulted from a slow growth caused by osmotic stress imposed by a high concentration of salts in the rooting zone. 28 biswas et al. fig. 1. effect of growth regulators on plant height of foxtail millet at 20 and 40 days after salt imposition (dasi). bars indicate (± se). leaf fresh weight leaf fresh weight foxtail millet was affected by plant growth regulators at 20 and 40 days after salt imposition (figure 2). leaf fresh weight was reduced due to salinity but the higher reduction was found at 40 days after salt imposition. plant growth regulators increased leaf fresh weight under saline conditions. at 20 days after salt imposition the maximum leaf fresh weight was measured 2.11 g when ha was sprayed @ 5 g l-1 water and it was minimum (1.67 g) when sa was applied @ 100g l-1 water. the maximum leaf fresh weight was found 5.86 g when plant growth regulator ha was applied @ 5g l-1 water, followed 5.83 g and 5.64 g and the minimum fresh weight was observed 5.19 g, when ha @ 10g l-1 water, ga3 10 g l-1 water and sa 50 g l-1 water were applied, respectively (figure 2). the spray of sa improved for instance shoot fresh weight per plant by 46.05%, ga3 40.42% and tria by 33.22% over the water-sprayed control in menthapiperita reported by daraksha and mohammad (2018). the alleviation in growth of plants due to pgrs especially sa may be traced to the fact that pgrs increase membrane permeability, cell division and cell enlargement. the favorable response of plants to pgrs has also been reported by yildirim et al. (2008), babar et al. (2014) and özkan and baydar (2016). amelioration of salinity tolerance in foxtail millet 29 fig. 2. effect of growth regulators on leaf fresh weight of foxtail millet at 20 and 40 days after salt imposition (dasi). bars indicate (± se). stem fresh weight it was found that stem fresh weight of foxtail milled decreased under the saline condition at vegetative stage and higher reduction was found at 40 days after salt imposition (figure 3). plant growth regulators increased stem fresh weight under salinity stress. at 20 days after salt imposition the maximum stem fresh weight was found 2.87 g from ha @ 5 g l-1watertreatment and the minimum stem fresh weight was found 2.61 g from ga3 g l-1watertreatment. on the other hand, at 40 days after salt imposition, the maximum stem fresh weight was recorded 9.99 g from ha @ 5 g l-1watertreated plant and the minimum was 8.31 g from sa @ 100 g l-1watertreatment (figure 3). qureshi et al. (2013) reported that ga3either applied singly or among calcium chloride, radically increased the vegetative growth parameters by increasing plant height, crown diameter, canopy spread, fresh and dry weight of plant and leaves, leaf area, fruit set percentage, number of, runners, trusses, flowers and fruits in strawberry. 30 biswas et al. fig. 3. effect of growth regulators on stem fresh weight of foxtail millet at 20 and 40 days after salt imposition (dasi). bars indicate (± se). total fresh weight the total fresh weight of foxtail millet also affected by salinity as well as plant growth regulators. total fresh weight was decreased due to salinity and a higher reduction was found at 40 days after salt imposition than 20 days after salt imposition. plant growth regulator increased total fresh weight under salinity. at 20 days after salt imposition, the maximum total fresh weight was 4.98 gplant-1, followed by 4.91 g plant-1, 4.48 g plant-1 and the minimum was 4.39 g plant-1 when ha treated plant @ 5g l1water, ha @ 10g l-1water, ga3 @ 20 g l-1waterand sa @ 100 g l-1waterrespectively (figure 4). at 40 days after salt imposition maximum total dry weight (15.86 g) was recorded from ha @ 5 g l1watertreatment and it was a minimum 13.52 g when plant was treated with sa @ 100 g l-1 water (figure 4). salicylic acid, in comparison with gibberellic acid also showed some favorable effects on accumulation of fresh weight which supported by the work of amborabe et al. (2002) and karlidag et al. (2009) on fresh weight accumulation in strawberry plant shoots with further agreement with the finding of khodary (2004) in increasing the total weight of plants in case of zea mays as compared to control. amelioration of salinity tolerance in foxtail millet 31 fig. 4. effect of growth regulators on total fresh weight per plant (g) of foxtail millet at 20 and 40 days after salt imposition (dasi). bars indicate (± se). spad value spad value of leaf of foxtail millet was recorded from 7 days after salt imposition to 42 days after salt imposition at 7 days intervals. it was found that spad value was increased up to 28 days under saline condition then spad value decreased. among the plant growth regulators ha @ 5 g l-1waterhad the positive effects of increasing spad value under salinity (figure 5). other plant growth regulators had no positive effects on spad value of foxtail millet leaves. it indicates that longer the exposure to salinity stress higher the decreases the spad value.purcarea and cachita-cosma(2011) reported that sa pre-treatment as a foliar spray ameliorated the total chlorophyll (spad) pigment content of wheat seedling leaves under salt stress. chlorophyll content the chlorophyll content of foxtail millet leaf was reduced significantly at salinity stress conditions. the highest total chlorophyll (1.70 mg g-1) was found in the control condition and it was lowest (0.58 mg g-1) under saline condition (figure 6). 32 biswas et al. fig. 5. effect of growth regulators on spad value of foxtail millet at different days after salt imposition (dasi). bar indicate (±se). total chlorophyll content increased when different plant growth regulators were applied under saline conditions. among the different plant growth regulators, ha @ 5 g l-1waterproduced the highest total chlorophyll (1.20 mgg-1) and it was lowest (0.75 mgg-1) for sa @ 100 g l-1water. when plants are grown under saline conditions, photosynthetic activity decreases leading to reduced plant growth, leaf area, chlorophyll content and chlorophyll fluorescence reported by muhammad et al. (2007). photosynthesis is one of the most severely affected processes during salinity stress (sudhir and murthy, 2004) owing to decrease in stomatal conductance, internal co2 partial pressure (sultan et al., 1999) and stomatal closure that affects the gaseous exchange (bethkey and drew 1992). this positive effect of sa could be attributed to increased co2 assimilation and photosynthetic rate and increased mineral uptake by the stressed plant under sa treatment (khan et al., 2000; fariduddin et al., 2003; szepsi et al., 2005). zeid (2011) also reported an alleviation of adverse effect of salinity on chlorophyll content in barley with ga3 treatment. ali et al. (2012) recorded restoration of altered pigments by application of ga3 under saline condition in hibiscus sabdariffa. exogenously applied sa significantly enhanced net photosynthetic rate which could be due to improving the functional state of the photosynthetic machinery in plants either by the mobilization of internal tissue nitrate or by chlorophyll biosynthesis (shi et al., 2006). amelioration of salinity tolerance in foxtail millet 33 fig. 6. effect of growth regulators on total chlorophyll content of foxtail millet at flowering stage bar indicate (±se). proline content proline is a kind of stress protein. proline accumulation under stress condition occurred because calvin cycle of photosynthesis affected by salinity stress; as a result, n content could not be properly metabolized content of foxtail millet varied significantly with different doses of plant growth regulators under salinity conditions (figure 7). the lowest proline content (0.08 µ moleg-1) was found under the control condition but under salinity, proline content increased and it was 1.54µ moleg-1. when plant growth regulators were applied under saline conditions proline content were decreased compared to solely saline treatment. the lowest proline content (1.20µ moleg-1) was recorded from ha @ 5 g l1watertreatment compared to other plant growth regulators treatment. lower accumulation of proline under saline condition after application of synthetic amendments (plant growth regulators) indicates that synthetic amendments reduce the salinity effects on winter pulses. kasim and dowidar (2006) observed lower proline content inga3 primed radish seedlings under nacl treatment. they suggested that, this decrease in the amino acid in ga3 primed seedlings may be due to their incorporation in some new proteins or their utilization in the synthesis of certain existing proteins. 34 biswas et al. fig. 7. effect of growth regulators on proline content of foxtail millet at flowering stage bar indicate (±se). dry matter production leaf, stem, root and total dry weight of foxtail millet plant reduced under saline condition. different plant growth regulators increased the dry matter of different plant parts (table 1). the highest leaf dry matter (2.54 g) was recorded from ha @ 5 g l-1watertreatment, followed by 2.21 g, 1.84 g and the lowest dry leaf weight (1.30 g) found from ha @ 10g l-1water, ga3 @ 5 g l-1waterand sa 50 g l1watertreatment, respectively. the highest stem dry matter (6.65 g) was recorded from ha @ 5 g l1watertreatment, followed by 3.80 g, 3.66 g and the lowest dry leaf weight (3.45 g) found from ga @ 10 g l-1water,ha @ 10 g l-1waterand sa 50 g l-1watertreatment, respectively. the highest root dry matter (0.71 g) was recorded from ha @ 5g l-1watertreatment, followed by 0.65 g, 0.57 g and the lowest root dry weight (0.47 g) found from ha @ 10g l-1water, ga3 @ 10 g l-1waterand sa 100 l1watertreatment, respectively. the highest total dry matter (9.90 g) was recorded from ha @ 5 g l1watertreatment, followed by 6.52 g, 6.21 g and the lowest dry leaf weight (5.27 g) found from ha @ 10g l-1water, ga3 @ 10 l-1waterand sa 50 g l-1watertreatment, respectively. reduction in dry matter production under saline condition was also reported by patil et al. (1996) and raptan et al. (2001) in mungbean. increasing salinity level resulted in significant reductions of shoot biomass, root length and volume. amelioration of salinity tolerance in foxtail millet 35 table 1. effect of growth regulators on dry matter production of foxtail millet under saline condition at harvest treatments leaf dry weight (g plant-1) stem dry weight (g plant-1) root dry weight (g plant-1) total dry weight (g plant-1) control 2.22 4.20 1.15 7.57 saline (8 dsm-1) 1.13 (50.90) 3.27 (77.85) 0.40 (34.78) 4.8 (63.41) saline + ha (5 g l-1water) 2.54 (114.41) 6.65 (158.33) 0.71 (61.73) 9.90 (130.78) saline + ha (10 g l-1water) 2.21 (99.94) 3.66 (87.14) 0.65 (56.52) 6.52 (86.125) saline + ga3 (10g l-1water) 1.84 (82.83) 3.80 (90.47) 0.57 (49.56) 6.21 (82.03) saline + ga3 (20g l-1water) 1.62 (58.56) 3.54 (84.29) 0.56 (48.70) 5.27 (69.62) saline + sa (50 g l-1water) 1.30 (62.61) 3.45 (82.14) 0.52 (45.22) 5.27 (69.62) saline + sa (100g l-1water) 1.39 (62.61) 3.47 (82.62) 0.47 (40.87) 5.33 (70.41) lsd(0.05) 0.22 0.85 0.72 0.72 cv (%) 7.3 1.4 6.6 9.0 hahumic acid, ga3-gibberelic acid, sasalicylic acid; values in parenthesis indicates % of control yield and yield contributing characters salinity decreased panicle length, panicle dry weight and yieldplant-1of foxtail millet however, the application of plant growth regulators increased in this parameter (table 2). the highest panicle length was 12.37 cm under the saline condition when plant growth regulator ha @ 5 g l-1 water was applied. the lowest panicle length (8.98 cm) was recorded when sa was applied @ 100 g l-1 water at saline condition. the highest panicle dry weight (3.70 g) was recorded from ha @ 5 g l-1 water treatment, followed by 3.57 g, 3.29 g and the lowest dry leaf weight (3.05 g) found from ha @ 10g l-1 water, ga3 @ 10 g l-1 water and sa 50 g l-1 water treatment, respectively. the highest grain yield (7.69 g) was recorded from ha @ 5 g l-1water treatment, followed by 6.66 g, 5.41 g and the lowest grain yield (3.91 g) obtained from ha @ 10g l-1 water, ga3 @ 10 g l-1 water and sa 50 g l-1 water treatment, respectively. the exogenous application of pgrs like auxins, gibberellins, cytokinins produces some benefit in alleviating the adverse effects of salt stress and also improves germination, growth, development and seed yields and yield quality (egamberdieva, 2009; majid et al., 2011, khan et al., 2004, afzal et al., 2006). na and k in straw plant growth regulators significantly influenced the straw na (%) and k (%) in foxtail millet (figure 8). it was found that salinity increased na (%) and decreased k (%) in straw compared to the control condition. different plant growth regulators decreased na (%) and increased k (%) under saline conditions. the highest reduction of na (%) was found in ha @ 5 g l-1 water treatment and the lowest reduction was in treatment sa @ 100g l-1 water. on the other hand the highest increase of k (%) in straw was found in treatment ha @ 5 g l-1 water and it was lowest in treatment sa @ 50 g l-1 water under saline condition. exogenous application of nutrients, iaa, or their combination considerably reduced na+ concentration and significantly improved k+, ca2+, and p levels in the salt stressed maize plants reported by cengiz kaya et al. (2013). 36 biswas et al. table 2. effect of growth regulators on panicle length, panicle dry weight and yield of foxtail millet under saline condition treatments panicle length (cm) panicle dry weight (g plant-1) grain yield (g plant-1) control 15.79 3.88 10.18 saline (8 dsm-1) 8.23 (52.12) 2.61 (67.26) 3.40 (33.40) saline + ha (5 g l-1water) 12.37 (78.34) 3.70 (95.36) 7.69 (75.54) saline + ha (10g l-1water) 10.10 (63.96) 3.57 (92.01) 6.66 (65.42) saline + ga3 (10g l-1water) 9.71 (61.49) 3.29 (84.79) 5.41 (53.14) saline + ga3 (20g l-1water) 9.37 (58.56) 3.19 (82.21) 5.08 (49.90) saline + sa (50g l-1water) 9.14 (57.88) 3.05 (78.61) 3.91 (38.41) saline + sa (100g l-1water) 8.98 (56.87) 3.17 (81.70) 4.01 (39.39) lsd(0.05) 0.72 1.03 0.50 cv (%) 3.8 4.1 4.9 hahumic acid, ga3-gibberelic acid, sasalicylic acid; values in parenthesis indicates % of control fig. 8. effect of growth regulators on straw na and k content of foxtail millet at harvest. bar indicate (±se). conclusion application of plant growth regulators increased plant height, leaf fresh weight, stem fresh weight as well as total dry weight, spad value, chlorophyll content but decreased proline content in foxtail millet under saline condition. plant growth regulators increased panicle length, panicle dry weight and amelioration of salinity tolerance in foxtail millet 37 finally yield of foxtail millet at the saline condition. among the plant growth regulators applied humic acid @ 5 g l-1 water showed the best performance in improving the salinity tolerance in foxtail millet. acknowledgement we are grateful to the university grants commission (ugc) of bangladesh for funding the research. references ali, y., z. aslam, m.y. ashraf and g.r. tahir. 2004. effect of salinity on chlorophyll concentration, leaf area, yield and yield components of rice genotypes grown under saline environment. int. j. env. sci. tech. 1(3):221–225. ali, h.m.h, siddiqui, m.o. basalah, m.h. al-whaibi, a.m. sakran and a. al-amri. 2012. effects of gibberellic acid on growth and photosynthetic pigments of hibiscus sabdarifa l. under salt stress. african j. biotech. 11(4): 800-804. amborabe, b.e., p.f. lessard, j.f. chollet and g. roblin. 2002. antifungal effects of salicylic acid and other benzoic acid derivatives towards eutypa lata structure-activity relationship. plant physiol. biochem. 40: 1051-1060 afzal, i., s.m.a. basara, m. farooq and a.nawaz.2006. alleviation of salinity stress in spring wheat by hormonal priming with aba, salicylic acid and ascorbic acid. int. j. agric. biol. 8:23-28. akita, s. and g.s. cabuslay.2003. physiological basis of differential response to salinity in rice cultivars. in: proc. 3rd. int. symp. genet. aspects plant minner. nutr. braun schwing, german. 27, 1988 anonymous, agricultural statistics of pakistan. government of pakistan, ministry of food, and live stock, economic wing, islamabad. aziz, m.a. 2003. growth, yield and some physiological mechanisms of salinity tolerance in mungbean. a ph. d (doctoral dissertation, thesis. dept. of agronomy, bsmrau, salna, gazipur. babar, s., e.h. siddiqi, i. hussain, k.h. bhatti and r. rasheed. 2014. mitigating the effects of salinity by foliar application of salicylic acid in fenugreek. physiol. j. https://doi.org/10.1155/2014/869058 (article id 869058). bari. 2000. krishi projokti hatboi. bangladesh agricultural research institute, joudebpur, gazipur. bates, l.s., r.p. waldren and i.d. teare. 1973. rapid determination of free proline for water-stress studies. plant soil 39(1): 205-207. bethkey, p.c. and m.c. drew. 1992. stomatal and non-stomatal components to inhibition of photosynthesis in leaves of capsicum annuum during progressive exposure to nacl salinity. plant physiol. 99: 219-226. cengiz kaya, m. ashraf, m. dikilitas and l. atillatuna. 2013. alleviation of salt stress-induced adverse effects on maize plants by exogenous application of indoleacetic acid (iaa) and inorganic nutrients. australian j. crop sci. 7(2): 249-254. daraksha, k and f. mohammad. 2018. plant growth regulators ameliorate the ill effect of salt stress through improved growth, photosynthesis, antioxidant system, yield and quality attributes in mentha piperita l. acta physiol. plant. 40: 188 https://doi.org/10.1007/s11738-018-2769-6. egamberdieva, d. 2009. alleviation of salt stress by plant growth regulators and iaa producing bacteria in wheat. acta. physiol. plant 31: 861-864. egeh, a.o. and o.b. zamora. 1992. growth and nutrient content of mungbean (vigna radiata l.), cowpea (vigna unguiculata l.) and soybean (glycine max. l.) under different levels of salinity. philippine j. crop sci. 4: 175-177. https://doi.org/10.1155/2014/869058 https://doi.org/10.1155/2014/869058 38 biswas et al. fariduddin, q., s. hayat and a. ahamad. 2003. salicylic acid influences net photosynthetic rate, carboxylation efficiency, nitrate reductase activity, and seed yield in brassica juncea. photosynthetica, 41: 281-284. gomez, k.a and a.a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. hossain, m.i., m.a. mannan and m.a. karim. 2015. salicylic acid and gibberelic acid ameliorates the adverse effects of salinity on chickpea. bangladesh agron. j. 18(1): 81-88. jackson, m.l. 1973. estimation of phosphorus content: soil chemical analysis. printer hall, new delhi (india). karlidag, h., e. yildirim and m. turan. 2009. salicylic acid ameliorates the adverse effect of salt stress on strawberry. sci. agric. 66(2): 180-187. kasim, w.a. and s. dowidar. 2006. amino acids and soluble protein profile of radish seedlings under salt stress as affected by ga3 priming. indian j. plant physiol. 11(1): 75-82. khan, m.b., m. shafi and j. bakht. 2000. yield and yield components of pearl millet as affected by various salinity levels. pakistan j. biol. sci. 3: 1393-1396. khan, m.a., b. gul and d.j. weber. 2004. action of plant growth regulators and salinity on seed germination of ceratoides lanata. can. j. bot. 82: 37-40. khodary, s.e.a. 2004. effect of salicylic acid on the growth, photosynthesis and carbohydrate metabolism in salt stressed maize plants. int. j. agric. biol. 6: 5-8. liu z, g. bai, d. zhang, c. znu, x. xia, z. cheng and z. shi. 2011. genetic diversity and population structure of elite foxtail millet (setaria italic (l.) p. beauv.) germplasm in china. crop sci. 51: 1655–1663. maggio, a., n. barbieri, d. raimondi and s. pascale. 2010. contrasting effects of ga3 treatments on tomato plants exposed to increasing salinity. j. plant growth regul. 29: 63-70. majid, g., a. javid, f. sorooshzadeh, s. moradi, a. mohammad, s. modarres and i. allahdadi. 2011. the role of phytohormones in alleviating salt stress in crop plants. australian. j. crop. sci. 5(6): 726734. meloni, d.a., m.a. oliva, c.a. martinez and j. cambraia. 2003. photosynthesis and activity of superoxide dismutase, peroxidase and glutathione reductase in cotton under salt stress. environ. expt. bot. 49: 69-76. muhammad, m., m.a.t. chowdhury and i. sarwar. 2007. floristic condition and species distribution in sundarban mangrove forest community, bangladesh. j. bio. sci. 7(2): 384-388. munns, r and m. tester. 2008. mechanisms of salinity tolerance. ann. rev. plant biol. 59: 651-681. nardi, s., d. pizzeghello, a. muscolo and a. vianello. 2002. physiological effects of humic substances on higher plants. soil biol. biochem. 34(11): 1527-1536. özkan, c. and n.g. baydar. 2016. brassinosteroid effects on some physical and biochemical properties and secondary metabolite accumulation in peppermint (mentha piperita l.) under salt stress. ind crops prods. 86: 251–258. patil, s.l., c.s. hunshal, b.t. nadagouda, r.n. kori and s.r. salakinakop. 1996. dry matter accumulation in lentil as influenced by saline water irrigation. adv. agril. res. india, 6: 78-87. purcarea, c. and d. cachita-cosma. 2011. salicylic acid involvement in salt stress alleviation in wheat (triticum aestivum cv. crisana) seedlings. studia universitatis “vasilegoldiş”, seria ştiinţele vieţii. 21(3): 607-614. qureshi, k.h., c. saman, s.q. usman and a.a. nadeem. 2013. impact of exogenous application of salt and growth regulators on growth and yield of strawberry. pak. j. bot. 45(4): 1179-1185. ramanjulu, s. and c. sudhakar. 2001. alliviation of nacl salinity stress by calcium is partly related to the increased proline accumulation in mulberry (morusalba l.) callus. j. plant biol. 28: 203-206. raptan, p.k., a. hamid, q.a. khaliq, a.r.m. solaiman, j.u. ahmed and m.a. karim. 2001. salinity tolerance of blackgram and mungbean. korean j. crop sci. 46(5): 380-386. amelioration of salinity tolerance in foxtail millet 39 saidimoradi, d., n. ghaderi and t. javadi. 2019. salinity stress mitigation by humic acid application in strawberry (fragaria x ananassa duch.). scientia hort. 256(15): 108594. shaded, m.a.k., e.l. abel, h.m. samad and d. mostafa. 2013. role of gibberelic acid (ga3) in improving salt stress tolerance of two wheat cultivars. int. j. plant physiol. biochem. 5(4): 50-57. shi, q., .z. bao, z. zhu, q. ying and q. qian. 2006. “effects of different treatments of salicylic acid on heat tolerance, chlorophyll fluorescence, and antioxidant enzyme activity in seedlings of cucumis sativa l,” plant growth reg. 48(2): 127–135. sudhir, p. and s.d.s. murthy. 2004. effect of salt stress on basic processes of photosynthesis. photosynthetica 42(2): 481-486. sultan, n.t., t. ikeda and r. itoh. 1999. effect of nacl salinity on photosynthesis and and dry matter accumulation in developing rice grains. env. expt. bot. 42: 211-220. szepesi, a., j. csiszar, s. bajkan, k. gemes, f. horvath, l. erdei, a.k. deer, m.l. simon and i. tari. 2005. role of salicylic acid pre-treatment on the acclimation of tomato plants to saltand osmotic stress. acta biol. szegediensis, 49: 123-125. vajpayee, p., r.d. tripathi, u.n. rai, m.b. ali and s.n. singh. 2000. chromium (vi) accumulation reduces chlorophyll biosynthesis, nitrate reductase activity and protein content in nymphaea alba l. chemosphere. 41: 1075-1082. vetriventhan, m., h.d. upadhyaya, c.r. anandakumar, s. senthilvel, h.k. parzies, a. bharathi and r.k. varshnev. 2012. assessing genetic diversity, allelic richness and genetic relationship among races in icrisat foxtail millet core collection. plant genetic res. 10(3): 214-223. witham, f.h., d.f. blaydes and r.m. devlin. 1986. chlorophyll absorption spectrum and quantitative determination. expt. plant physiol. pp.55-56. yildirim, e., m. turan and i. guvenc. 2008. effect of foliar salicylic acid applications on growth, chlorophyll, and mineral content of cucumber grown under salt stress. j. plant nutr. 31: 593–612. zeid, i.m. 2011. alleviation of seawater stress during germination and early growth of barley. int. j. agric. res. rev. 1(2): 59-67. https://www.sciencedirect.com/science/article/abs/pii/s0304423819304832 https://www.sciencedirect.com/science/journal/03044238 abstract introduction materials and methods results and discussion conclusion acknowledgement references saidimoradi, d., n. ghaderi and t. javadi. 2019. salinity stress mitigation by humic acid application in strawberry (fragaria x ananassa duch.). scientia hort. 256(15): 108594. bangladesh agron. j. 2019, 22(2): 113-127 effect of biochar application as a soil amendment on growth and yield of sesame (sesamumindicuml.) t.s. roy1*, m.t. rahman1, r. chakraborty1, m. mostofa2 and m.s. rahman3 1 department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2 tuber crops research centre, bangladesh agricultural research institute, gazipur-1701, bangladesh 3 department of biochemistry, sher-e-bangla agricultural university, dhaka-1207, bangladesh corresponding e-mail: tuhinsuvraroy@sau.edu.bd (received: 19 february 2020, accepted: 26 april 2020) keywords:biochar, growth, yield, sesamumindicum abstract the experiment was conducted to study the effect of biochar on growth and yield of sesame. in the experiment, the treatment consisted of three varieties, viz., v1 = bari til2, v2 = bari til-3 and v3 = bari til-4, and five levels of biocharviz., b0= control (no biochar application), b1= 2 t ha-1, b2= 4 t ha-1, b3= 6 t ha-1 and b4= 8 t ha-1. the experiment was laid out in two factors randomized complete block design (rcbd) with three replications.variety, application of different levels of biochar and their interaction showed statistically significant variation in plant height, number of leaves plant-1at 55 and 80 das and at harvest, capsules plant-1, seeds capsule-1, 1000-seed weight, seed yield, stover yield, biological yield and harvest index.the highest plant height (70.34, 110.95 and 109.84 cm at 55 and 80 das and at harvest respectively), number of leaves plant-1 (80.47, 116.70 and 94.54 at 55, 80 das and at harvest, respectively), number of branches plant-1 (3.60), capsules plant-1(80.47), number of seeds capsule-1(56.02),seed yield(1.07tha-1)andharvestindex(36.46%)were observed in the variety bari til-4 cultivated with the application of biochar @ 6 t ha-1 (v3b3) and the lowest one was observed in variety bari til-2 with no biochar application (v1b0).biochar is effective for increasing growth and yield of sesame. introduction sesame (sesamumindicum l.) is one of the important edible oilseed cultivated in bangladesh. its oil content generally varies from 46-52% and protein between 20-26%. the oil is used foredible purpose (73%), hydrogenation (8.3%) and industrial purpose (4.2%) in the manufacture of paints, pharmaceuticals and insecticides. sesame oil is also used in soap, cosmetics and skincare. it has antiviral, antibacterial, antifungal and antioxidant properties (ray, 2009). a hundred grams of sesame seed provide 592 calories energy. sesame oil is the poor man’s substitute for “ghee”. sesame as an industrial crop which is potent economically and highly nutrient, per 36 grams of seed contains 206.2 kal, copper 1.48 mg, mn 0.88 mg, tryptophan 0.12 g, ca 351 mg, mg 126.36 mg, fe 5.24 mg, p 226.44 mg, zn 2.8 mg, b1 vitamin 0.28 mg and fiber 4.24 g (ray, 2009). sesame oil contains oil that ranges between 40 to 50% that is edible and has long shelf life more than one year without any deterioration due to its content of sesamol antioxidant, rich in unsaturated fats especially oleic acid and linoleic acid (shararet al., 2000).it contains 6.0 -6.2 % nitrogen, 2.0 2.2 percent phosphorus and 1.0 -1.2 percent potash. it can be used as manure. the cake is edible and is eaten avidly by working classes. it is also a valuable and nutritious feed for milch cattle. sesame is one of the most important oil crops in bangladesh and grown in all regions. total area coverage of sesame is 33,974.57 hectors with an annual production of 31,232 metric tones during fiscal year 2017-18 (bbs, 2019). the yield of sesame is much lower in the farmer’s field as compared to the 114 roy et al. researchfield. mianetal.(2002)stated that sesame yield is very low in bangladesh due to a lack of proper management practices. the yield of sesame can be increased by nutrient management, which is very important for yield improvement of the crop. biochar is a soil amendment.it provides a better and more nourishing environment for plant roots. it must be mixed thoroughly within the soil. if it is just placed under the soil, it can interfere with the movement of water or air and the growth of the plant roots can be affected (davis and wilson, 2012).biochar is a pyrolyzed biomass produced under limited oxygen or oxygen absent conditions. the specific intention of biochar application to soil is to improve its agronomic and biochemical quality (sun and lu, 2013; liu et al., 2014), and to enhance carbon sequestration (lehmann and rondon, 2006). the use of biochar can be an effective tool for sustainable agriculture in the long term, increasing soil carbon sequestration (c abatement strategy), fertility and productivity (soil quality) and reducing greenhouse gas emissions (jeffery et al., 2013). it can increase soil aeration (laird, 2008) and reduce soil emissions of n2o, a greenhouse gas (spokaset al., 2010).the addition of biochar as amendment materials to agricultural soils is receiving much attention due to the apparent benefits of biochar to soil quality and enhanced crop yields, as well as the potential to gain carbon credits by active carbon sequestration (major, 2010). considering the low yield of sesame obtained in most growing areas as the reason of the non-application of fertilizers and the poor fertility status of soil.application of biochar can increase growth and yield of sesame and also improve soil fertility(wacalet al., 2019). in this scenario,theinvestigation was conducted to study the effect of biocharapplication as a soil amendment on growth and yield of sesame. materials and methods the experiment was conducted at the agronomy research field of thesher-e-bangla agricultural university, dhaka, bangladeshfrom march to june 2017.geographically the experimental field was located at 23° 77′ n latitude and 90° 33' e longitudes at an altitude of 9 m above the mean sea level.the morphological, physical and chemical characteristics before and after harvesting of sesame of the experimental plot soil have been presented in table 1.the weather condition during the study period (march-june) hasbeen presented in table 2. table 1.soil characteristics of experimental farm of sher-e-bangla agriculturaluniversity (before and after harvesting of sesame) a. morphological characteristics of the experimental field morphological features characteristics location farm, sau, dhaka aez modhupur tract (28) general soil type shallow red brown terrace soil land type high land soil series tejgaon topography fairly leveled flood level above flood level drainage well drained cropping pattern n/a source:soil resource development institute (srdi), farmgate, dhaka, bangladesh b. physical and chemical properties of the initial soil physical and chemical properties of the initial soil characteristics value practical size analysis sand (%) 16 silt (%) 56 clay (%) 28 effect of biochar application as a soil amendment 115 silt + clay (%) 84 textural class silty clay loam ph 5.56 organic matter (%) 1.00 total n (%) 0.06 available p (μ g/g soil) 42.64 available k (meq/100 g soil) 0.13 source: soil resource development institute (srdi), farmgate, dhaka, bangladesh c. chemical properties of the soil after harvesting of sesame (treatment wise averageresult) treatment ph oc (%) total n (%) available p (µg g-1soil) exchangeable k (meq 100g-1soil) b0 6.09 0.40 0.039 14.52 0.23 b1 5.84 0.48 0.048 17.59 0.26 b2 5.96 0.58 0.057 21.13 0.30 b3 6.04 0.64 0.064 25.58 0.36 b4 5.89 0.70 0.073 29.29 0.40 source: department of soil scienece, faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh table 2. monthly average temperature, relative humidity and total rainfall of theexperimental site during the period from march 2017 to june 2017 month air temperature (°c) relative humidity (%) total rainfall (mm) maximum minimum march 33.6 20.4 67 100 april 36.5 23.9 73 228 may 37.0 25.9 73 188 june 36.1 26.5 80 414 source: bangladesh agricultural research council (climate information management system), dhaka, bangladesh three sesame varieties viz.,bari til-2, bari til-3 and bari til-4 were used as planting material. seeds of all the varieties were collected from bangladesh agricultural research institute (bari), joydebpur, gazipur-1701.the treatment consisted of three sesame varieties, viz., v1 = bari til-2, v2 = bari til-3, v3 = bari til-4 and five levels of biocharviz., b0= control (no biochar application), b1= biochar @ 2 t ha-1, b2= biochar @ 4 t ha-1, b3= biochar @ 6 t ha-1 and b4= biochar @8 t ha-1. the experiment was laid out in two factors randomized complete block design (rcbd) with three replications.there were 15 treatment combinations and 45unit plots. the unit plot size was 3.60 m2 (1.8 m2.0 m). the blocks and unit plots were separated by 0.50 m and 0.3 m spacing respectively.therecommended doses of urea, tsp, mop, gypsum, zinc sulfate and boric acid as per bari (2014) @125, 150, 50, 110, 5 and10 kg ha-1 were applied in the soil of each plot. all fertilizers were applied as basal dose except urea,whichwas applied in 2 splits.seeds were sown in the furrow on 28march 2017. different intercultural operations such as thinning, weeding, irrigation,drainageand plant protection measures were done when needed.the crop was harvested at 87 daswhen about 80% of the pods became matured. samples were collected from each plot leavingundisturbed plants in the center. the sample bundles were sun-dried by spreading those on the threshing floor. the seeds were separated, cleaned and dried in the sun for 3 to 5 consecutive days for achieving safe moisture of seed.the dried seeds and straw were cleaned and weighed. ten plants were collected randomly from each plotto measure average data of plant height (cm), number of leaves plant-1(no.), capsules plant116 roy et al. 1(no.),seeds capsule-1 (no.), weight of 1000 seeds (g),seed yield (t ha-1), stover yield (t ha-1), biological yield (t ha-1) and harvest index (%). biological yield and harvest index were calculated with the following formula; biological yield = grain yield + stover yield.harvest index (%) = ���� ����� ���������� ����� 100 the collected data were compiled and analyzed statistically using the analysis of variance (anova) technique with the help of a computer package program statistix 10 and the mean differences were adjusted by least significance difference (lsd) test at 5% level of significance. results and discussion plant height varieties showed statistically significant variation in respect of plant height of sesame (figure1). among the varietiesbari til-4 (v3) showed the highest plant height (68.29, 107.72 and 106.64 cm at 55, 80 das and at harvest, respectively). the lowest plant height (60.51, 95.44 and 95.43 cm at 55, 80 das and at harvest, respectively) was observed in the bari til-2 (v1). variations in plant height among sesame varieties had been reported extensively (ghungardeet al., 1992). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.865, 1.255 and 1.24 at 55, 80 das and at harvest, respectively). fig. 1. effect of varieties on plant height of sesame at different days after sowing. the plant height of sesame was significantly influenced by different levels of biochar application (figure 2) (wacalet al., 2019). at 55, 80 das and at harvest, the highest plant height (66.13, 104.30, and 103.58 cm, respectively) was recorded in the application of biochar@ 6 t ha-1 (b3) which was statistically similar with the application of biochar@ 8 t ha-1 (b4) where the lowest was measured at 55, 80 das and harvest (61.74, 97.39 and 96.72 cm, respectively) in control (b0). 60 .5 1 95 .4 4 95 .4 3 64 .4 3 10 1. 62 10 0. 6 68 .2 9 10 7. 72 10 6. 64 0 20 40 60 80 100 120 55 das 80 das at harvest pl an t h ei gh t ( cm ) days after sowing (das) v1 v2 v3 effect of biochar application as a soil amendment 117 b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 1.476, 1.622 and 1.601 at 55, 80 das and at harvest respectively). fig. 2. effect of different levels of biochar on plant height of sesame at different days after sowing table 3. interaction effect of varieties and different levels of biochar on plant height of sesame at different days after sowing (das) interaction plant height (cm) 55 das 80 das harvest v1b0 58.19 g 91.78 h 91.77 i v1b1 60.11 fg 94.81 g 94.81 h v1b2 60.99 f 96.20 g 96.19 h v1b3 61.67 f 97.28 g 97.27 gh v1b4 61.58 f 97.12 g 97.11 gh v2b0 61.67 f 97.27 g 96.30 h v2b1 63.67 f 100.43 f 99.42 fg v2b2 64.58 e 101.87 ef 100.85 ef v2b3 66.36 de 104.67 de 103.62 de v2b4 65.84 cd 103.85 de 102.81 de v3b0 65.37 cd 103.11 ef 102.08 ef v3b1 67.50 bc 106.46 cd 105.39 cd v3b2 68.46 ab 107.98 b 106.90 bc v3b3 70.34 a 110.95 a 109.84 a v3b4 69.79 a 110.08 ab 108.9 ab cv (%) 1.933 2.806 2.773 lsd(0.05) 6.37 7.31 6.55 ls ns ** ** figures in a column followed by different letter(s) differ significantly whereas figures having common letter(s) do not differ significantly from each other as adjusted by lsd. cv= coefficient of variation, ls= level of significance, lsd (0.05) = least significant difference, ns= non significant, **= significant at 1% level of probability. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1. van zwietenet al. (2010) reported a nearly 30-40 percent increase in wheat height when biochar was applied @ 10 t ha-1 to acidic soil. wacalet al. (2016) found that the plant height of sesame was significantly influenced by the biocharapplication.the interaction effect between varieties and different levels of biochar exerted a significant effect on plant height at 80 das and harvest (table 3). the 61 .7 4 97 .3 9 96 .7 2 63 .7 6 10 0. 57 99 .8 7 64 .6 8 10 2. 02 10 1. 32 66 .1 3 10 4. 3 10 3. 58 65 .7 4 10 3. 68 10 2. 97 0 20 40 60 80 100 120 55 das 80 das at harvest pl an t h ei gh t ( cm ) days after sowing (das) b0 b1 b2 b3 b4 118 roy et al. highest plant height (110.95 and 109.84 cm at 80 das and harvest, respectively) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1 (v3 b3). the lowest plant height (91.78 and 91.77 cm at 80 das and at harvest, respectively) was observed in the variety bari til-2 with no biochar application (v1 b0). number of leavesplant-1 varieties showed a significant variation in the number of leaves plant-1 of sesame (figure 3). among the different varietiesbari til-4 (v3) showed the highest number of leaves plant-1(78.13,113.30 and 91.79 at 55, 80 das and at harvest, respectively). the lowest number of leaves plant-1(69.22, 100.39 and 77.31 at 55, 80 das and at harvest, respectively) was producedby the varietybari til-2 (v1). leaves plant-1of sesame was significantly influenced by different levels of biochar application(figure4). at 55, 80 das and at harvest, the highest number of leaves plant-1 (75.65, 109.71 and 86.41, respectively) was recorded in the application of biochar @ 6 t ha-1 (b3)and the lowest was achieved with control (b0) (70.64, 102.43 and 80.68,respectively). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.769, 1.159, and 0.735 at 55, 80 das and at harvest, respectively). fig. 3. effect of varieties on number of leaves plant-1 of sesame at different days after sowing (das). b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.990, 1.496 and 0.956 at 55, 80 das and at harvest, respectively). fig. 4. effect of different levels of biochar on number of leaves plant-1of sesame at different days after sowing (das) the interaction effect between varieties and different levels of biochar exerted a significant effect on the number of leaves at all das (table 4). the highest number of leaves (80.47, 116.70 and 94.54 at 55, 80 das and harvest, respectively) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1(v3b3)at harvest. the lowest number of leaves (66.55,96.54 and 74.35 69 .2 2 10 0. 39 77 .3 1 73 .7 10 6. 9 83 .3 8 78 .1 3 11 3. 3 91 .7 9 0 50 100 150 55 das 80 das at harvest n um be r o f l ea ve s/ pl an t days after sowing (das) v1 v2 v3 70 .6 4 10 2. 43 80 .6 8 72 .9 4 10 5. 8 83 .3 1 73 .9 9 10 7. 31 84 .5 1 75 .6 5 10 9. 71 86 .4 1 75 .2 10 9. 07 85 .9 0 50 100 150 55 das 80 das at harvest n um be r o f l ea ve s/ pl an t days after sowing (das) b0 b1 b2 b3 b4 effect of biochar application as a soil amendment 119 at 55, 80 das and harvest, respectively) was observed in variety bari til-2 with no biocharapplication (v1b0) at 55 das, 80 das and harvest. table 4. interaction effect of varieties and different levels of biochar on number of leaves plant-1 of sesame at different days after sowing (das) interaction number of leaves plant-1 55 das 80 das harvest v1b0 66.57 j 96.54 i 74.35 i v1b1 68.77 i 99.76 h 76.80 h v1b2 69.77 hi 101.17 h 77.92 gh v1b3 70.56 h 102.33 h 78.80 gh v1b4 70.44 hi 102.17 h 78.67 gh v2b0 70.55 h 102.31 h 79.82 g v2b1 72.84 g 105.67 g 82.41 f v2b2 73.89 fg 107.17 fg 83.59 ef v2b3 75.92 de 110.10 de 85.89 e v2b4 75.32 ef 109.23 ef 85.22 d v3b0 74.79 ef 108.43 ef 87.86 d v3b1 77.21 cd 111.97 cd 90.71 c v3b2 78.32 bc 113.60 bc 92.01 bc v3b3 80.47 a 116.70 a 94.54 a v3b4 79.84 ab 115.80 ab 93.80 ab cv (%) 1.721 2.591 2.345 lsd(0.05) 5.46 9.54 5.42 ls ** ** ** figures in a column followed by different letter(s) differs significantly whereas figures having common letter(s) do not differ significantly from each other as adjusted by lsd. cv= coefficient of variation, ls= level of significance, lsd(0.05) = least significant difference, **= significant at 1% level of probability. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1. number of branches plant-1 varieties showed a significant variation in the number of branches plant-1 of sesame (figure5). bari til-4(v3) showed the highest number of branches plant-1 (3.48)whereasthe lowest number of branches plant-1 (3.11) was observed in variety bari til-2 (v1). variation in the number of branches plant-1 due to variety was also reported by asharaniet al.(1992).branches plant-1 was significantly influenced by different levels of biochar application at different das of sesame (figure5) (wacalet al., 2019). the highest number of branches plant-1 (3.49) was recorded in the application of biochar@ 6 t ha-1 (b3) which was statistically similar to the application of biochar@ 8 t ha-1(b4) and the lowest number of branches plant-1(3.02) was achieved with control (b0). 120 roy et al. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.047). b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.061). fig. 5. effect of varieties and different levels of biocharon number of branches plant-1 of sesame. the interaction effect between varieties and different levels of biochar exerted a significant effect on the number of leaves (table 5). the highest number of leaves (3.60) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1 (v3b3). the lowest number of leaves (2.73) was observed variety bari til-2 with no biocharapplication (v1b0) at 55 das, 80 das and harvest. number of capsulesplant-1 the number of capsulesplant-1 showed significant variation due to the effects of sesame variety (figure6).the highest number of capsules plant-1 (78.13) was obtained from the varietybari til-4 (v3). the lowest number of capsulesplant-1(73.70) was found in the variety bari til-3 (v2).the number of capsules plant-1 was significantly influenced by different levels of biochar application of sesame (figure6). it was remarked from the present study that the increasing rate of biochar significantly increased the number of capsules plant-1. application of biochar@ 6 t ha-1 (b3) treatment produced a maximum number of capsules plant-1 (75.41) which was statistically similar result with the application of biochar@ 8 t ha-1 (b4). the lowest number of capsules plant-1(70.08) was achieved with control (b0). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.897).b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 1.159). fig.6. effect of varieties on number of capsules plant-1 of sesame. 3. 11 3. 31 3. 48 3. 02 3. 24 3. 29 3. 49 3. 44 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 v1 v2 v3 b0 b1 b2 b3 b4 n um be r o f b ra nc he s/ pl an t varieties and different levels of biochar 73 .7 67 .8 1 78 .1 3 70 .0 8 72 .3 6 73 .3 9 75 .4 1 74 .8 2 60 65 70 75 80 v1 v2 v3 b0 b1 b2 b3 b4 n um be r o f c ap su les /p lan t varieties and levels of biochar effect of biochar application as a soil amendment 121 the interaction effect between varieties and different levels of biochar exerted a significant effect on the number of capsules plant-1(table 5). the highest capsule plant-1 (80.47) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1(v3b3) which was statistically similar result bari til-4 cultivated with the application of biochar@ 8 t ha-1(v3b4). the lowest number of capsules per plant(70.55) was observed in the variety of bari til-2 with no biochar application (v1b0). number of seeds capsule-1 sesame varieties showed a significant variation in the number of seedscapsule-1 (figure7). among the different varieties bari til-4 (v3)showed the highest number of seedscapsule-1(54.39). the lowest number of seedscapsule-1(49.17) was recorded in varietybari til-3 (v2). genetically controlled character might be increased the vegetative growth and development of sesame that lead to the highest number of seedscapsule-1(deshmukhet al.,1990).results presented in figure 7 on number of seeds capsule-1influenced by different levels of biochar application were statistically significant. the highest number of seedscapsule-1(49.57) was recorded in application of biochar@6 t ha-1 (b3) which was statistically similar to application of biochar@ 8 t ha-1 (b4). the lowest number of seeds capsule1(46.07) was recorded by control (b0). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.897).b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.1.159). fig.7. effect of varieties on number of seeds capsule-1 of sesame. the interaction effect between varieties and different levels of biochar showed a significant effect on seeds capsule-1at harvest (table 5). the highest seeds capsule-1(56.02) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1(v3b3) which was statistically similar to the result obtained from v3b4. the lowest seeds capsule-1(47.07) was observed in thevariety bari til-2 with no biocharapplication (v1b0). weight of 1000 seeds varieties showed a significant variation on thousand seed weight (figure8). bari til-3 (v2)showed the highest thousand seed weight (3.10g)whereasthe lowest thousand seed weight (2.94 g) was recorded in variety bari til-2 (v1). results showed that the weight of 1000 seeds was significantly influenced by different levels of biochar application (figure8). the highest weight of 1000 seeds (3.10 g) was recorded in application of biochar@ 6 t ha-1 (b3) which was statistically similar with application of biochar@ 8 t ha-1 (b4) whereas the lowest weight of 1000 seeds (2.89 g) was achieved by control (b0). wacalet al. (2016) found that 1000-seed weight was significantly influenced by biochar application. 49 .1 7 40 .8 3 54 .3 9 46 .0 7 47 .5 7 48 .2 5 49 .5 7 49 .1 8 0 10 20 30 40 50 60 v1 v2 v3 b0 b1 b2 b3 b4 se ed s/ ca ps ul e varieties and different levels of biochar 122 roy et al. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.041).b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.052). fig.8. effect of varieties and different levels of biocharon 1000 seed weightof sesame the interaction effect between varieties and different levels of biochar showed a significant effect on the weight of 1000 seeds at harvest (table 5). the highest weight of 1000 seeds (3.18g) was observed in the bari til-3 cultivated withthe application of biochar @ 6 t ha-1(v2b3). the lowest 1000-seed weight (2.81 g)was observed in the variety bari til-2 with no biocharapplication (v1b0). table 5. interaction effect of varieties and different levels of biochar on yield attributes of sesame interaction branches plant-1 (no.) capsules plant-1 (no.) seeds capsule-1 (no.) 1000 seeds weight (g) v1b0 2.73 h 70.55 h 47.07 h 2.81 i v1b1 3.07 f 72.84 g 48.59 g 2.90 gh v1b2 3.13 f 73.89 fg 49.29 fg 2.94 f-h v1b3 3.33 de 75.92 de 50.64 e 3.02 c-f v1b4 3.27 e 75.32 d-f 50.25 ef 3.00 d-f v2b0 2.93 g 64.91 k 39.09 k 2.97 e-h v2b1 3.27 e 67.01 j 40.35 j 3.06 c-e v2b2 3.33 de 67.98 ij 40.93 ij 3.10 a-c v2b3 3.53 ab 69.84 hi 42.06 i 3.18 a v2b4 3.47 bc 69.30 hi 41.73 i 3.16 ab v3b0 3.40 cd 74.79 e-g 52.06 d 2.89 hi v3b1 3.40 cd 77.21 cd 53.75 c 2.98 e-g v3b2 3.40 cd 78.32 bc 54.52 bc 3.02 c-f v3b3 3.60 a 80.47 a 56.02 a 3.10 a-c v3b4 3.60 a 79.84 ab 55.58 ab 3.08 b-d cv (%) 8.52 2.008 1.256 0.091 lsd(0.05) 0.105 4.53 6.51 2.54 ls ** ** ** ** figures in a column followed by different letter(s) differs significantly whereas figures having common letter(s) do not differ significantly from each other as adjusted by lsd. **= significant at 1% level of probability. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1. 2. 94 3. 1 3. 01 2. 89 2. 98 3. 02 3. 1 3. 08 2.75 2.8 2.85 2.9 2.95 3 3.05 3.1 3.15 v1 v2 v3 b0 b1 b2 b3 b4 10 00 se ed w eig ht (g ) varieties and different levels of biochar effect of biochar application as a soil amendment 123 seed yield bari til-4 (v3) gave the highest yield (1.01 t ha-1) (figure 9). on the contrary, the lowest seed yield (0.88 t ha-1) was observed with variety bari til-2 (v1).variation in seed yield of sesame due to variety was also reported by many researchers (asharaniet al., 1992). seed yield of sesamewas significantly influenced by the application of different levels of biochar (figure9). the highest seed yield (1.03 t ha-1) was recorded in application of biochar@6 t ha-1 (b3) which was statistically similar to application of biochar@ 8 t ha-1 (b4) while the lowest seed yield (0.85 t ha-1) was achieved by control (b0). wacalet al. (2016) found that the seed yield of sesame was significantly influenced by the biochar application.ndoret al. (2015) found that the application of 10 tha-1 of sawdust and rice husk biochar produced the highest seed weight of sesame. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.014).b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.019). fig.9. effect of varieties and different levels of biocharon seed yield of sesame. the interaction effect between varieties and different levels of biochar showed a significant effect on seed yield at harvest (table 6). the highest seed yield (1.07 t ha-1) was observed in the variety bari til-4 cultivated with the application of biochar@ 6 t ha-1(v3b3) which was statistically similar to the result obtained from v3b4. the lowest seed yield (0.75 t ha-1) was observed in the variety bari til-2 with no biocharapplication (v1b0). stover yield different varieties showed significant variations in respect of the stover yield of sesame (figure 10). among the different varieties bari til-2 (v1) showed the highest stover yield (2.31 t ha-1). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.033). b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.043). fig.10. effect of varieties and different levels of biocharon stover yield of sesame. 0. 88 0. 96 1. 01 0. 85 0. 92 0. 97 1. 03 1 0 0.2 0.4 0.6 0.8 1 1.2 v1 v2 v3 b0 b1 b2 b3 b4 se ed y ie ld (t /h a) varieties and different levels of biochar 2. 31 1. 89 1. 87 1. 96 2 2. 01 2. 06 2. 08 0 0.5 1 1.5 2 2.5 v1 v2 v3 b0 b1 b2 b3 b4 st ov er y ie ld (t /h a) varieties and different levels of biochar 124 roy et al. the lowest stover yield (1.87 t ha-1) was observed with bari til-3 (v2) which was statistically similar to v3 (bari til-4). stover yield of sesame varied significantly due to different levels of biochar applications (figure 10). the highest stover yield (2.08 t ha-1) was observed from application of biochar@ 8 t ha-1 (b4) which was statistically similar to b3 while the lowest stover yield (1.96 t ha-1) from control (b0). the interaction effect between varieties and different levels of biochar showed a significant effect on strove yield (t ha-1) at harvest (table 6). the highest stover yield (2.42 t ha-1) was observed in the variety bari til-2 cultivated with the application of biochar@ 8 t ha-1 (v1b4). the lowest stover yield (1.83 t ha-1) was observed in the variety bari til-4 with 2 t ha-1biochar application (v3b1). biological yield different varieties showed significant variations in respect of the biological yield of sesame (figure 11). among the different varieties bari til-2 (v1) showed the highest biological yield (3.19 t ha1).the lowest biological yield (2.86 t ha-1) was observed with v2 (bari til-3) which was statistically similar with bari til-4 (v3).the biological yield was significantly influenced by different levels of biochar application (figure 11). the maximum biological yield (3.09 t ha-1) was recorded in application of biochar @ 6 and 8 t ha-1 (b3 and b4) and the minimum biological yield (2.82 t ha-1) was achieved by control (b0). the application of 6 to 8 t c ha-1 increased rice biomass by 17 percent while the presence of 135t c ha-1 of biochar enhanced the growth by 43 percent (lehmann et al., 2003). v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; (lsd (0.05) 0.041).b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1; (lsd (0.05) 0.052). fig.11. effect of varieties and different levels of biocharon biological yield of sesame. the interaction effect between varieties and different levels of biochar showed a significant effect on biological yield at harvest (table 6). the highest biological yield (3.37 t ha-1) was observed in the variety bari til-2 cultivated with the application of biochar @ 8 t ha-1 (v1b4) which was statistically similar to v1b3. the lowest biological yield (2.73 t ha-1) was observed in the variety bari til-3 with no biochar application (v2b0). harvest index different varieties showed significant variations in respect of the harvest index of sesame (figure12). bari til-4 (v3) showed the highest harvest index (35.15 %). on the contrary, the lowest harvest index (27.66 %) was observed with bari til-2 (v1).the harvest index was significantly influenced by different levels of biochar application (figure12). it stated from the presentstudy that the highest harvest index (33.40 %) was recorded in application of biochar @ 6 t ha-1 (b3) and the lowest harvest index (30.43%) was achieved by control (b0). 3. 19 2. 86 2. 89 2. 82 2. 92 2. 98 3. 09 3. 09 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 v1 v2 v3 b0 b1 b2 b3 b4 bi ol og ica l y ie ld (t /h a) varieties and different levels of biochar effect of biochar application as a soil amendment 125 v1 = bari til-2, v2 = bari til-3, v3 = bari til-4, (lsd (0.05) 0.486). b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1, (lsd (0.05) 0.682). fig.12. effect of varieties and different levels of biochar on harvest index of sesame. the interaction effect between varieties and different levels of biochar showed a significant effect on harvest indexat harvest (table 6). table 6. interaction effect of varieties and different levels of biochar on yield and harvest indexof sesame interaction seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) hi (%) v1b0 0.75 j 2.17 d 2.92 cd 25.78 g v1b1 0.83 i 2.32 bc 3.15 b 26.38 g v1b2 0.92 g 2.26 c 3.18 b 28.90 ef v1b3 0.98 de 2.36 ab 3.34 a 29.24 e v1b4 0.94 e-g 2.42 a 3.37 a 28.02 f v2b0 0.87 h 1.86 gh 2.73 f 31.91 d v2b1 0.94 e-g 1.87 f-h 2.81 ef 33.57 c v2b2 0.97 d-f 1.86 f-h 2.83 de 34.35 bc v2b3 1.03 bc 1.95 e 2.98 c 34.50 bc v2b4 1.01 cd 1.93 ef 2.94 c 34.24 bc v3b0 0.94 fg 1.86 gh 2.80 ef 33.62 c v3b1 0.98 de 1.83 h 2.80 ef 34.85 b v3b2 1.02 c 1.91 e-g 2.93 c 34.78 b v3b3 1.07 a 1.87 f-h 2.94 c 36.46 a v3b4 1.06 ab 1.89 e-h 2.95 c 36.05 a cv (%) 0.033 0.074 0.091 1.088 lsd(0.05) 6.67 7.85 6.54 2.01 ls ** * * * figures in a column followed by different letter(s) differs significantly whereas figures having common letter(s) do not differ significantly from each other as adjusted by lsd. cv= coefficient of variation, ls= level of significance, lsd(0.05)= least significant difference, *= significant at 5% level of probability, **= significant at 1% level of probability. v1 = bari til-2, v2 = bari til-3, v3 = bari til-4; b0 = control, b1 = 2 t ha-1, b2 = 4 t ha-1, b3 = 6 t ha-1, b4 = 8 t ha-1. 27 .66 33 .71 35 .15 30 .43 31 .6 32 .68 33 .4 32 .77 0 5 10 15 20 25 30 35 40 v1 v2 v3 b0 b1 b2 b3 b4 h ar ve st in de x (% ) varieties and differnt levels of biochar 126 roy et al. the highest harvest index (36.46%) was observed in the variety bari til-2 cultivated with the application of biochar @ 8 t ha-1 (v3b3) which was statistically similar to v3b4. the lowest harvest index (25.78%) was observed in the variety bari til-2 with no biochar application (v1×b0). conclusion the results in this study indicated that the sesame variety bari til-4 performed better with the application of biochar@ 6 t ha-1in respect of growth and yield properties compared to other treatment combinations. references asharani, n.r.,j.s. prakasaraoand t. annapurnamma.1992. effect of planting dates on phenology growth and yield of sesame cultivars (sesamumindicum l.). j. res. 20(1): 36-38. bari (bangladesh agricultural research institute). 2014. krishiprojuktihatboi (handbook of agrotechnology). bangladesh agril. res. inst. joydebpur, gazipur 1701:129-132. bbs (bangladesh bureau of statistics). 2019. yearbook of agricultural statistics. ministry of planning, government of the people's republic of bangladesh. retrieved on april24, 2020. davis, j.g. and c.r. wilson.2012. choosing a soil amendment, annual report of colorado state university. deshmukh, v.a., d.a. chevan and g.t. sugave.1990. response of sesamum (sesamumindicum l.) to nitrogen and phosphate. indian j. agron. 35(3):314. ghungarde, s.r., d.a. chavan, u.n. alse, g.v. yeagaonkar and v.n. pangarkar. 1992. effect of plant density and variety on yield of sesamum (sesamumindicum l.). indian j. agron. 37(2):385-386. jeffery, s., t.m. bezemer, g. cornelissen, t.w. kuyper, j. lehmann, l. mommer, s.p. sohi., t.f.j.v.d. voorde, d.a. wardle and j.w.v. groenigen.2013. the way forward in biochar research: targeting trade-offs between the potential wins. gcb bioenergy. 7(1):1-13. laird, d.a. 2008. the charcoal vision: a win-win-win scenario for simultaneously producing bioenergy, permanently sequestering carbon, while improving soil and water quality. agron. j. 100(1):178181. lehmann, j. and m. rondon. 2006. biocharsoil management on highly weathered soils in the tropics. in: uphoff, n., ball. a.s., fernandes, e., herren, h., husson, o., laing, m., palm, c., pretty, j., sanchez, p., sanginga, n. and thies, j. (eds): biol.appr.sust. soil syst.: 518-527. lehmann, j., jr.j.p. da silva,c. steiner, t. nehls, w. zechand b. glaser. 2003. nutrient availability and leaching in an archaeological anthrosol and ferralsol of the central amazon basin: fertilizer, manure and charcoal amendments. plant soil. 249:343-357. liu, c., m. lu, j. cui, b. li and c. fang. 2014. effects of straw carbon input on carbon dynamics in agricultural soils: a meta-analysis. global change biol. 20(5):1366-1381. major, j., j. lehmann, m. rondon andc. goodale. 2010. fate of soil-applied black carbon: downward migration, leaching and soil respiration. global change biol. 16(4):1366-1379. mian, m.a.k., a. ahmed and a. matin. 2002. growth, yield economics of hybrid maize as influenced by rate and time of nitrogen application. bangladesh j. agril. res. 27(1): 41-46. ndor, e., o. jayeoba and c. asadu. 2015. effect of biocharsoil amendment on soil properties and yield of sesame varieties in lafia, nigeria. am. j. exp. agric. 9(4):1-8. ray, h. 2009. sesame profile content specialist, agmrc, iowa state university, iowa,. sharar, m.s., a. choudhry and m. asif.2000. growth and yield of sesame genotypes as influenced by np application.int. j. agric. biol. 2:1-2. spokas, k.a., j.m. baker and d.c. reicosky. 2010. ethylene: potential key for biochar amendment impacts. plant soil. 333(1-2):443-452. effect of biochar application as a soil amendment 127 sun, f.and s. lu. 2013. biochars improve aggregate stability, water retention, and pore-space properties of clayey soil. j. plant nutr. soil sci. 177(1):26-33. van zwieten, l., s. kimber, s. morris, a. downie, e. berger, j. rust and c. scheer. 2010. influence of biochars on flux of n2o and co2 from ferrosol. soil res. 48(7):555-568. wacal, c., d. sasagawa, d. basalirwa, r. acidri and e. nishihara.2016. effect of biochar on continuously cropped sesame (sesamumindicum l.). conference: the 241st meeting of cssj (crop science society of japan), at ibaraki university-japan. wacal, c., n. ogata, d. basalirwa, t. handa, d. sasagawa, r. acidri, t. ishigaki, m. kato, t. masunaga, s. yamamoto ande. nishihara. 2019. growth, seed yield, mineral nutrients and soil properties of sesame (sesamumindicum l.) as influenced by biocharaddition on upland field converted from paddy. agron. 9(2):55. bangladesh agron. j. 2015, 18(2): 97-104 grain growth and yield of wheat as influenced by variety and sowing date r. uddin1, m. s. islam2*, m. j. ullah2 and p. k. hore2 and s. k. paul4 1rars, bari, rahmatpur 2department of agronomy, sher-e-bangla agricultural university, dhaka 3agronomy division, bari, joydebpur, gazipur *corresponding author: msislamsau@yahoo.com key words: wheat variety, sowing date, grain growth, yield abstract a field experiment was conducted at the agronomy field, sher-e-bangla agricultural university, dhaka during november 2012 to april 2013 to evaluate the influence of variety and sowing date on grain growth and yield of wheat. the experiment consisted of four wheat variety viz., bari gom-21, bari gom-24, bari gom-25 and bari gom-26 and three sowing date viz., 20 november, 01december and 12 december. grain growth, yield contributing characters and yield of wheat were significantly influenced by different variety and sowing date. among the variety, bari gom-24 and bari gom-25 showed initial lower lag phase duration of 8 days after anthesis (daa) and 12 daa, respectively than bari gom-21 (16 daa) sown at 01 december. the maximum grain growth rate whole over the period was maintained by bari gom-26 sown at 01 december. it reached peak at 20 daa (1.17 mg /grain/day). the minimum growth rate was maintained by bari gom-21 and bari gom-24 sown at 12 december (0.15 mg /grain/day). bari gom-25 sown at 01december gave the highest yield (4.6 t ha−1) whereas bari gom-21 sown at 20 november gave the lowest (2.67 t ha−1). all the wheat varieties sown at 01 december yielded better than 20 november and 12 december sowing. introduction wheat (triticum aestivum l) is an important cereal grain crop in bangladesh as well as in the world. it ranks first globally and second most important cereal next to rice in bangladesh in terms of production and acreage (bbs, 2013; fao, 2009). estimated land, on which wheat is cultivated in bangladesh, is 358 thousand hectare and average yield is 2780 kg ha−1 (ais 2013). wheat is one of the winter season crops in bangladesh. winter is becoming shorter due to climate change. therefore, wheat production may be affected. wheat requires different temperatures at different stages of plant growth and development. temperature requirement may slightly differ from one variety to another. however, the optimum temperature required for wheat is 20° to 25° c and the maximum temperature is 35° c. if temperature is more than 300c at the time of maturity, it leads to force maturity and yield loss. the optimum temperature for wheat anthesis and grain filling ranges from 12 to 22◦c. exposure to temperatures above this can significantly reduce grain yield (tewolde et al., 2006; fisher, 2007). post-anthesis heat stress in wheat induces several physiological effect which eventually result in smaller grain weight due to reduced grain filling period and starch synthesis duration or the combined effect of both (hasan and ahmed 2005). the annual mean temperature of bangladesh is 25.75°c, which is expected to rise about 0.21°c by 2050 (karmakar and shrestha, 2000). the organization for economic co-operation and development (oecd) (2003) estimated arise in temperature of 1.4°c by 2050 and 2.4°c by 98 uddin et al. 2100 in bangladesh. islam (2009) estimated from 34 meteorological climate sites in bangladesh, that temperature increases over the past 100 years or all bangladesh of 0.62°c (maximum) and 1.54°c (minimum) occurred in february. poulton and rawson (2011) reported that temperature in bangladesh increased over the past two decades by 0.035°c/ year. if this trend continues, temperatures will have increased 2.13°c more than 1990 levels by 2050. the rising temperature effect of global warming by crop modeling and simulation technique revealed that the warming is already slowing yield gains as a majority of wheat growing locations. global wheat production is estimated to fall by 6% for each 0c for further temperature increase and become more variable over space and time (assenge et al. 2015). identification of wheat genotypes suitable for heat stress condition would be an important step for achieving high yield potential of wheat. the information is very limited regarding grain growth of wheat under different temperature. therefore, the investigation was done to observe the grain growth rate and yield of wheat varieties sowing at different dates. materials and methods the experiment was conducted at the agronomy farm, sher-e-bangla agricultural university, dhaka-1207 during november 2012 to april 2013. the soil was silty clay loam having low organic matter (0.78%) and slightly acidic soil (ph 5.6). the location of the site was 23°74' n latitude and 90°35' e longitude with an elevation of 8.2 meter from sea level. the experiment consisted of two factors of variety and sowing date. the wheat variety viz., bari gom-21 (v1), bari gom-24 (v2), bari gom-25 (v3) and bari gom-26 (v4) and sowing date viz., 20 november (s1), 01 december (s2) and 12 december (s3) were arranged in rcb design with three replications. the unit plot size was 3m × 2m. the land was prepared by ploughing and cross-ploughing with the power tiller followed by laddering uniformly. seed was treated with vitavex@3g/kg seed. the crop was fertilized with 120-30-90-15-3-1 kg npksznb ha-1 (frg, 2012). data on grain growth, yield contributing characters and yield were recorded. for grain growth study, three ears were harvested from each plot after anthesis at four days interval. it was continued up to 24 days after anthesis (daa). the harvested ears were oven dried at 70 °c for 72 hours. twenty grains of each genotype were separated from the middle of each spike and then weight was taken. collected data were statistically analyzed by mstat-c. the treatment means were compared by the least significant difference (lsd) test at 5% level (gomez and gomez, 1984). results and discussion grain growth as influenced by variety and sowing date grain growth rate of four wheat variety grown under different sowing dates were varied remarkably (fig. 2). initially the grain growth of wheat had a lag phase due to low dry matter accumulation. among the variety, bari gom-21 maintained maximum duration in lag phase (16 daa) for three sowing date. initial lag phase duration mean temperature was ranged from 12.7-24.5°c whereas the rapid linear phase mean temperature was ranged from 16.727.5°c and for terminal lag phase the mean temperature was ranged from 19.9-31.60c. bari gom-24 and bari gom-25 sowing at different dates maintained minimum duration in lag phase (8 daa). in bari gom-26, lag phase for 20 november and 12 december sowing was up to 8 daa, but 01 december sowing maintained higher grain growth rate than others. after the completion of lag phase grain growth of four wheat variety increased rapidly. among the different sowing dates, 01 december sowing maintained higher grain growth rate in all over the grain filling period. it might be due to prevailing optimum temperature (fig. 2). grain growth rate reached peak at 20 daa. the maximum growth rate was observed in 99 grain growth and yield of wheat as influenced by variety and sowing date bari gom-26 sown at 01 december (1.17mg/grain/day) and the minimum was observed in bari gom-21 (0.15 mg/grain/day). the maximum grain growth of bari gom-26 sown at 01 december indicated that the variety was more capable to accumulate dry matter in grain than others. karim et al. (2000) supported that grain growth pattern indicates that both higher growth rate and longer growth duration in heat tolerant wheat are responsible for its higher grain yield under late sowing conditions. fig 1. monthly mean temperature (max. and min.) 0c, relative humidity (%) and rainfall (cm) during the cropping season 100 uddin et al. fig 2. grain growth rate of wheat varieties at different daa as influenced by sowing dates the grain growth results of this study was also supported by karim et al. (2000) regarding wheat grain growth. effect of variety plant characters of wheat varieties were significantly differed (table 1). the maximum number of days to reached anthesis was recorded in bari gom-21 (74 days) and the minimum was in bari gom-25 (71 days). bari gom-21 required maximum days to reach anthesis because its crop duration is about 120-125 days. bari gom-21 significantly produced the tallest plant (89.74 cm) while the shortest was bari gom-26 (85.49 cm). table 1. shows that wheat variety exhibited significant variations in number of total spike m-2 (215.6 to 243.1), grain number spike-1 (37.56 to 40.37), and 1000grain weight ( 36.67 to 40.91g). number of total spike m-2 exhibited narrow differences among the varieties. bari gom21 produced the lighter grain and bari gom-24 and bari gom-25 produced the heavier grain. but the grain yield of wheat was not significantly differed by variety. it might be due to narrow differences in yield contributing characters. the variations in yield contributing characters of wheat due to variety were also observed by tahir et al. (2009) and stone et al. (1995). effect of sowing date plant characters and yield were significantly differed by sowing dates (table 2). the crop sown at 12 december had longer vegetative phase (77 days) and shorter reproductive phase. the plant sown at 20 november showed the tallest height (90.23 cm) with minimum number of spike per unit area (210 m-2). the heavier grain weight (42.58 g) and number of 101 grain growth and yield of wheat as influenced by variety and sowing date grain per spike (42) were produced by 01 december sowing. grain yield had significantly differed by sowing date. the highest grain yield was obtained from 01 december sowing (4.36 t ha-1) and the lowest from 20 november sowing (3.00 t ha-1). the variations in yield and yield contributing characters of wheat due to sowing date were also observed by gul et al. (2012) and fisher (2007). table 1. effect of variety on plant characters, yield contributing characters and grain yield of wheat variety days to anthesis plant height (cm) grain spike-1 (no.) spike m-² (no.) 1000 grain wt. (g) grain yield (t ha-1) bari gom-21 74.33 89.74 40.11 226.4 36.67 3.35 bari gom-24 73.00 85.91 40.37 216.4 40.91 3.58 bari gom-25 71.33 87.03 37.56 234.6 40.34 3.57 bari gom-26 72.22 85.49 39.81 213.0 39.69 3.41 lsd(0.05) 1.02 0.99 2.01 12.36 2.79 ns cv (%) 1.44 1.17 5.20 5.68 7.24 7.94 table 2. effect of sowing date on plant characters, yield contributing characters and grain yield of wheat sowing date days to anthesis plant height (cm) grain spike-1 (no.) spike m-2 (no.) 1000 grain wt. (g) grain yield (t ha-1) 20 nov 69.33 90.23 38.19 209.6 37.58 3.00 01 dec 71.67 86.52 42.36 242.7 42.58 4.36 12 dec 77.17 84.38 37.83 215.6 38.04 3.08 lsd(0.05) 0.89 0.86 1.74 10.70 2.41 0.23 cv (%) 1.44 1.17 5.20 5.68 7.24 7.94 interaction effects of variety and sowing date plant characters, yield contributing characters and grain yield were significantly differed by the interaction effects of variety and sowing date (table 3). the maximum number of days to anthesis (79 days) was recorded in bari gom-24 sown at 12 december and the minimum from bari gom-25 sown at 20 november (67 days). bari gom-21 sown at 20 november showed the tallest plant (92.27 cm) while bari gom-24 sown at 01 december showed the shortest (82.40 cm). the highest number of spike was obtained from bari gom-21 sown at 20 november (263 m-2) and the lowest obtained from the same variety sown at 20 november (190 m-2). bari gom-26 sown at 01 december produced the highest 1000grain weight (43.83 g) while bari gom-25 sown at 12 december produced the lowest (34.87 g). the maximum number of grain per spike (45) was recorded in bari gom-26 sown at 01 december and the minimum from bari gom-25 sown at 20 november (34 spike-1). the highest grain yield (4.61 t ha-1) was obtained from bari gom-25 sown at 01 december which was identical with the grain yield obtained from bari gom-26 (4.53 t ha-1) and bari gom-21 (4.16 t ha-1) sown at the same date. the grain growth rate of bari gom-25 and bari gom-26 showed the shorter initial lag phase duration sown on 01 december than the other sowing dates and the grain filling duration continued after 24 daa where it faced terminal heat stress and switched to terminal lag phase (fig. 2). the maximum grain filling occurred at the optimum temperature (16.6-27.5°c) and maximum kernel mass was gained (fig. 1). hossain et al. (2012) supported the result that all wheat varieties, when sown late, faced severe temperature stress that significantly affected phenology, growth and finally yield. taking into consideration phenological variation, dry matter (fresh and dry weight) 102 uddin et al. partitioning and grain yield, variety ‘bari gom-26’ performed better both in optimum and late heat stress, followed by ‘bari gom-25’; ‘gourab’ performed the least. the lowest yield was recorded from bari gom-26 sown at 20 november (2.60 t ha-1). from the fig. 2 this is apparent that the longer initial lag phase duration of bari gom-26 sown at 20 november had lower grain growth rate. moreover, the rapid linear phase did not exhibit the sigmoid pattern and showed decreased kernel mass production than the other sowing dates. from the 20 daa, it started to enhance the grain growth rate where it faced the terminal heat stress (19.9-31.6°c) (fig. 1) mostly and this may be resulted in shorter grain filling period. stone et al. (1995) supported the result that reductions in mature kernel mass resulted primarily from reductions in duration rather than rate of grain filling. the previous findings of gupta et al. (2010), qasim et al. (2008), gul et al. (2012) and shirpurkar et al. (2007) in various wheat were also supported these results. table 3. interaction effects of variety and sowing date on plant characters, yield contributing characters and grain yield of wheat treatments days to anthesis plant height (cm) grain spike1 (no.) spike m-2 (no.) 1000-grain wt. (g) grain yield (t ha1) v1s1 71.00 92.27 38.78 190.3 36.13 2.671 v1s2 74.00 92.20 40.89 262.7 38.77 4.162 v1s3 78.00 84.77 40.67 226.3 35.10 3.226 v2s1 70.33 89.33 40.33 228.0 38.80 3.556 v2s2 70.00 82.40 42.78 221.0 43.67 4.128 v2s3 78.67 86.00 38.00 200.3 40.27 3.066 v3s1 67.00 91.00 33.78 224.0 42.10 3.173 v3s2 70.33 86.53 41.00 255.7 44.07 4.605 v3s3 76.67 83.57 37.89 224.0 34.87 2.944 v4s1 69.00 88.33 39.89 196.0 33.30 2.601 v4s2 72.33 84.93 44.78 231.3 43.83 4.531 v4s3 75.33 83.20 34.78 211.7 41.93 3.085 lsd(0.05) 1.78 1.73 3.47 21.4 4.83 0.46 cv (%) 1.44 1.17 5.20 5.68 7.24 7.94 v1: bari gom-21, v2: bari gom-24, v3: bari gom-25 and v4: bari gom-26 s1: sowing at 20 november s2: sowing at 1 december, s3: sowing at 12 december yield and yield components of wheat, significantly reduced under late seeding conditions, were also observed by tyagi et al. (2003), munjal et al. (2004). it might be due to lower dry matter accumulations in grain due to prevailing high temperature at grain filling period. the lower grain yield due to late sowing of wheat compared to optimum sowing also observed by islam et al. (1993), bhatta et al. (1994) and gul et al. (2012). conclusion bari gom-26 sown at 01 december performed better in relation to grain growth to produce heavier grain. at 01 december sowing, all the four wheat variety produced maximum grain yield. among the varieties, bari gom-25 yielded better than others. references 103 grain growth and yield of wheat as influenced by variety and sowing date ais (agriculture information service) 2013.. ministry of agriculture. govt. of the people’s republic of bangladesh. khamarbari, farmgate, dhaka. asseng, s., f. ewert, p. martre, r. p., rötter, d. b. lobell, d. cammarano. 2015. rising temperature reduce global wheat production. nature climate change 5: 143147. bbs (bangladesh bureau of statistics). 2013. statistical year book of bangladesh. statistical division, ministry of planning. govt, of the people’s republic of bangladesh, dhaka. bhatta, m. r., j. e. hernandez and j. s. lales. 1994. possibilities of selecting wheats with fast grain filling rate for warmer areas. in: d.a. saunders and g.p. hatel (ed.) wheat in heatstressed environments: irrigated. dry areas and rice-wheat farming system. cimmyt. mexico d.f. p. 375-378. fao (food and agricultural organization). 2009. production year book. an appraisal of seed biology and the yield of grain crops. cab. international. p. 112-121. frg 2012. fertilizer recommendation guide, 2012. bangladesh agricultural research council (barc), new airport road, farmgate, dhaka 1215. fisher, r. a. 2007. understanding the physiological basis of yield potential in wheat. j. agric. sci. 145: 99-113. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research (2nd edn.). int. rice res. inst. andwilley, new york pp. 28-192. gul, h., b. saeed, a. z. khan, u. latif, k. ali, j. rehman and s. rehman.2012. yield and yield contributing traits of wheat cultivars in relation with planting dates and nitrogen fertilization. arpn j. agril. biol. sci. 7(6):386395. gupta, a., m. gupta and b. r. bazaya. 2010. effect of sowing dates and genotypes on growth and yield of durum wheat (triticum durum l). j. res. skuast 9: 164-168. hasan, m. a. and ahmed j u. (2005). kernel growth physiology of wheat under late planting heat stress, j. natl.. sci. foundn. sri lanka. 33(3):193-204. hussain, a. and j.a. teixeira da silva. 2012. phenology, growth and yield of three wheat (triticum aestivum l.) varieties as affected by high temperature stress. not. sci. biol. 4(3):97-109. islam a.s. 2009. analyzing changes of temperature over bangladesh due to global warming using historic data. young scientists of asia conclave, jawaharlal nehru centre for advanced scientific research (jncasr), 15-17 january, jakkur, bangalore. karim, m. a., a. hamid and s. rahman. 2000. grain growth and yield performance of wheat under subtropical countries: ii. effect of water stress at reproductive stage. cereal res. comm. 28: 101-107. karmakar, s. and m. l. shresth. 2000. recent climatic changes in bangladesh. smrc no.4. saarc meteorological research centre, agargaon, dhaka, bangladesh munjal, r., s. s. dhanda, r. k. rana and i. singh. 2004. cell membrane thermo stability as an indicator of heat tolerance at seedling stage in bread wheat. natl. j. pl. imp. 6(2): 133135. qasim, m., m. qamer, faridullah and m. alam. 2008. sowing dates effect on yield and yield components of different wheat varieties. j. agril. res. 46: 304-315. oecd 2003. rising food prices: causes and consequences. 9 p. available online: http://www.oecd.org/dataoecd/54/42/40847088. pdf [accessed on the 20 january 2009]. 104 uddin et al. poulton, p. l. and m. h. rawson(2011). physical constraints to cropping in southern bangladesh, 256 p. in: rawson hm (ed.).sustainable intensification of rabi cropping in southern bangladesh using wheat and mungbean, aciar technical reports no. 78. australian centre for international agricultural research, canberra. shirpurkar, g. n., n. v. kashid and a. a. pisal. 2007. effect of different sowing dates and varieties on yield and yield attributes of wheat. agril. sci. digest. 27: 68-70. stone, p.j. and nicolas, m.e. (1995). effect of timing of heat stress during grain filling on two wheat varieties differing in heat tolerance.1. grain growth. aust. j. pl. physiol. 22(6): 927-934 tahir, m., a. ali, m.a. nadeem, a. hussain and f. khalif (2009). effect of different sowing dates on growth and yield of wheat (triticum aestivum l.) varieties in district jhang, pakistan. pak. j. life soc. sci. 7(1):66-69. tewolde, h., c. j. fernandez and c. a. erickson. 2006. wheat cultivars adapted to post-heading high temperature stress. j. agron. crop sci. 192: 111–120. tyagi, p. k., r. k. pannu, k. d. sharma, b. d. chaudhary and d. p. singh. 2003. effect of sowing time on performance of wheat genotypes. annals biol. 19(2): 119‐122. shot communication bangladesh agron. j. 2017, 20 (1): 106-108 screening non-improved zimbabwean sorghum land races for resistance to witch weed onismus chipfunde1* and mhosisi masocha2 1genetic resources and biotechnology institute, department of research and specialist services, p o box cy550 causeway, harare, zimbabwe 2mhosisi masocha, department of geography and environmental science, university of zimbabwe, p.o box mp 167 mount pleasant, harare, zimbabwe corresponding author, e-mail: ochipfunde@gmail.com key words: weed emergence, escape hypothesis, sorghum bicolor, striga asiatica, sorghum landraces sorghum is an important cereal for food security in semi-arid regions of the world (mukarumbwa and mushunje 2010). semi-arid regions are characterized by frequent droughts leading to crop failure. in addition to drought, sorghum production in the smallholder farming sector in sub-saharan africa can be undermined by the parasitic witch weed striga asiatica (l.) kuntze (stroud, 1993). s. asiatica parasitism can cause cereal yields to drop by as much as 60% hence it poses a threat to food security (mabasa, 1993). the aim of this study is to screen sorghum landraces for s. asiatica resistance and test the escape hypothesis through a controlled in a pot experiment. a pot experiment was established on 1 march 2013 at the henderson research station in zimbabwe. it is situated in agro-ecological region ii of zimbabwe. the annual average rainfall is 864 mm. mean annual temperature is 21 oc (mujere and mazvimavi, 2012). the dominant soil type is red clay loam belonging to the fersiallitic group (wulff et al. 2002). four sorghum (sorghum bicolor) landraces consisting of two early maturing and two late maturing varieties were obtained from the national genebank in harare for this experiment. the early maturing landraces were tsveta and nhongoro while the late maturing landraces were musoswe and khaki. the biological characteristics of these landraces including days to 50% flowering is shown in table 1. table 1. biological characteristics of four zimbabwean sorghum landraces used in early maturing landraces compared to late maturing landraces. sorghum landrace 1,000 seed weight (g) days to 50% flowering maximum height (cm) number of tillers head width (cm) tsveta 30.1 78 250 3 7 nhongoro 17.2 89 310 3 4 musoswe 18.9 95 335 4 6 khaki 34.4 97 260 6 7 source: genetic resources and biotechnology institute, 2009. the experimental units were four different sorghum land race plants grown under natural light with s. asiatica infection and the (uninfected) control. the experiment was conducted in randomized complete design with 6 replications. a total of 48 plastic pots with a volume of 5 litres were used for this experiment. half of the pots were filled with s. asiatica infected sandy soil while the other half was filled with uninfected sandy soil. to infect the soil with s. asiatica, the top 5 cm of the soil in the pot was mixed with 0.09 grams of s. asiatica seed (iitp,1997). in each pot, 20 107 screening non-improved zimbabwean sorghum land races for resistance to witch weed sorghum landrace seeds were obtained from the national genebank . after emergence, the plants were thinned to one plant per pot. all experimental units were fertilized at a rate of 2 grams per pot with compound d (that is, 8% nitrogen, 14% phosphate and 7% potassium) as the basal dressing followed by top dressing fertilizer at the rate of 2 grams per pot of ammonium nitrate (34.5% nitrogen) 3 weeks after planting. a second top dressing was applied at the start of the 5th week from planting at the same rate as the first top dressing. plant height was measured at the end of each week for 10 weeks and was analyzed using repeated measures to test whether the interaction of time and s. asiatica infection had a significant effect on the vegetative growth of the early and late maturing sorghum landraces. a t-test was used and statistical analyses were done by using statistica at 5% level of significance. table 2. variation in dry biomass yield (g) between four zimbabwean sorghum landraces grown in striga asiatica infected soil and uninfected soil sorghum landrace treatment control t-value df p-value tsveta 18.4 ± 9.7 15.4 ± 6.6 0.51 10 0.62 nhongoro 9.5 ± 8. 8 12.7 ± 4.6 0.64 10 0.54 musoswe 4.8 ± 3.7 4.3 ± 3.8 0.19 10 0.85 khaki 1.4 ± 0.7 8.7 ± 5.1 2.46 10 0.04 fig. 1. effect of striga asiatica infection on vegetative growth rate of two early maturing sorghum landraces, tsveta (a) and nhongoro (b) and two maturing sorghum landraces musoswe (c) and khaki (d) grown in s. asiatica infected soil and uninfected soil (control) for 10 weeks. 108 onismus chipfunde and mhosisi masocha control plants from two early maturing landraces (tsveta, nhongoro) and one late maturing landrace (musvoswe) grew faster than the treatment group during the first 8 weeks of the experiment (figure 1 a-c). however, these differences in height growth were not significant. by contrast, the vegetative growth of one late maturing landrace (khaki) was significantly suppressed by s. asiatica fig. 1d). the results for biomass yield followed a similar pattern. s. asiatica infection did not significantly reduce the biomass yield of two early maturing landrace and one late maturing landrace (table 2) but for khaki – a late maturing variety, the mean yield for the treatment group was eight times lower than that of the control. two early maturing landraces and one late maturing landrace used in this study appear to be resistant to s. asiatica parasitism. only one late maturing landrace (khaki) was sensitive to s. asiatica infection during the vegetative stage of growth. these results provide partial support to our hypothesis and imply that khaki is not a suitable candidate for development of s. asiatica resistant sorghum varieties. the growth suppression observed in this landrace confirm the findings of a previous study done in tanzania where s. asiatica significantly reduced both vegetative growth and shoot biomass in several scientifically improved sorghum varieties (makoko and sibuga 2003). this study reveals that early maturing zimbabwean sorghum landraces tend to be more resistant to s. asiatica parasitism compared to late maturing ones. it has identified three scientifically unimproved zimbabwean sorghum landraces that could be introgressed into commercial sorghum varieties to develop new sorghum varieties with a high resistance to s. asiatica parasitism. references iitp (international institute of tropical agriculture). 1997. striga research methods-a manual. second edition. international institute of tropical agriculture, ibadan, nigeria. mabasa, s. 1993. the status of striga control research and extension in zimbabwe. in: proceedings, third general workshop of the pan-african striga control network. p 131 mabasa, s. 1996. screening sorghum cultivars for resistence to witch weed (striga asiatica) in zimbabwe. in proceedings of the sadc/ icrisat regional sorghum and pearl millet workshop. plenum press, new york, london, gaborone, botswana. pp 201-209 makoko, b. r. and k. p. sibuga. 2003. preliminary screening of sorghum (sorghum bicolor) genotypes for tolerance/resistance to striga asiatica. in: african crop science conference proceedings. african crop science society, uganda. pp126-132 mujere, n. and d. mazvimavi. 2012. impact of climate change on reservoir reliability. african crop science j 20:545-551. mukarumbwa, p. and a. mushunje. 2010. potential of sorghum and finger millet to enhance household food security in zimbabwe’s semi-arid regions. joint 3rd african association of agricultural economists (aaae) and 48th agricultural economists association of south africa (aeasa) conference, , cape town, south africa. stroud, a. 1993. control of weeds. pages 172-187 in dryland farming in africa macmillan press, hong kong: technical centre for agriculture and rural co-operation. short communication bangladesh agron. j. 2017, 20 (1): 109-111 effect of different doses of herbicide (metro 70wg) on weed control in maize field santosh kumar paul1**, shamima akther2, towhidi almas mujahidi3, subarna kundu4 1= agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. 2= agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. 3= plant breeding division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. 4= planning and evaluation division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. corresponding author: santosh87dhaka@gmail.com key words: herbicide, metro 70wg, weeds, maize maize is the third important cereal crop in bangladesh. maize is valued for its diversified use. now a days it has been considered as crop for food security. it is can be directly consumed as a nutritious food. grains and plant are processed into other agro-industrial by-products. increased maize production can play a vital role in alleviating food shortage in bangladesh (paul et al., 2015). the stalk leaves of maize plant and shelled cobs can also be utilized in reducing existing fodder shortage. though maize production is very high, but due to lack of proper management yield is decreasing compared to other developed countries. weed infestation is one of them, which decreased the yield (turk et al., 2002). many herbicide are used to control the weeds in maize field. a field experiment was conducted at joydebpur, gazipur and regional agricultural research station, jamalpur of bangladesh agricultural research institute during the kharif-i season of 2012 to find out the optimum dose of herbicide metro 70wg for controlling weeds in maize field. six treatments viz. t1 = metro 70wg @ 250 gm ha-1 at sowing, t2 = metro 70wg @ 500 gm ha-1 at sowing, t3 = metro 70wg @ 750 gm ha-1 at sowing, t4 = weed free, t5 = two hand weedings at 20 days after planting (dap) and 35 dap and t6 = control (untreated) were used. seeds were sown on 21 march 2012 in joydebpur and 5 march 2012 in jamalpur at 60 cm x 20 cm spacing. crop variety used in the experiment was bari hybrid maize-7. the crop was fertilized with 250-55-110-40 kg npks/ha. thirty percent of n along with full amount of other fertilizers was applied as basal during final land preparation. remaining 70% n was applied as top dressed at 8-leaf stage. irrigation and other intercultural operations were done as and when required. the crop was harvested on 4th and 19th july, 2012 at jamalpur and joydebpur, respectively. collected data were analyzed statistically and mean separation was done by lsd test. the relative density (rd) and weed control efficiency (wec) were calculated by the following formula. relative density (rd) = 100 weedsof no. total species weedspecific of no  weed control efficiency (wec) = 100 plot control of dry wt. plot specific of dry wt.-plot control of dry wt.  110 paul et al. the common weeds in maize field were jussiaea repens (helencha), cyperus rotundus (mutha), echinochloa crusgalli (shama) and cynodon dactylon (durba). herbicide reduced weed infestation in maize but none of the herbicidal dose can exceed the weed control efficiency by hand weeding plot in both the locations. at 40 dae, among the different herbicidal treatments maximum weed control efficiency (wce: 45.32% at joydebpur and 20.49% at jamalpur) was found in treatment t2 (metro 70wg @ 500 gm ha-1) at jamalpur and in treatment t3 (metro 70wg @ 500 gm ha-1) at joydebpur, respectively. among the weed species, echinochola crusgalli (shama) was found dominant (16-40 weeds/m2) at 20 dae and 37-52 weeds/m2 at 40 dae. at jamalpur, weeds in the maize field comprise helencha, mutha, durba, kalimaina, biskathali, fulka and others. dry weight of weeds/ m2 varied at different dose of metro 70wg (table 1). maximum dry weight of weeds was recorded in control plots in both the locations. weed control efficiency (wce) was highest in hand weeding plots at both the locations. paul et al., 2014 also observed higher wce under two hand weddings at 20 and 40 das. although maximum wce was found in hand weeded plot but hand weeding is laborious, time consuming and expensive. among the different herbicidal treatments t2 (metro 70wg @ 500 gm ha-1 at sowing followed by irrigation) showed higher wce at 20 dae. the highest wce (45.32%) was found in t3 (metro 70wg @ 750 gm ha-1 at 40 dae (table 2). table 1. dry weight of weed and weed control efficiency in maize as affected by different doses of metro 70wg over locations treatments at 20 dae at harvest weed dry weight/m2 (g) wce (%) weed dry weight/m2 (g) wce (%) t1 58.63 21.11 135.5 35.29 t2 40.30 45.74 107.2 48.82 t3 40.95 44.90 171.6 17.92 t4 t5 14.60 80.35 61.30 70.73 t6 74.32 209.4 t1) metro 70wg @ 250 gm/ha, t2) metro 70wg @ 500 gm/ha, t3) metro 70wg @ 750 gm/ha, t4) weed free, t5) two hand weeding at 20 das and 35 das, t6) control (untreated) the maximum grain yield was found (9.44 t/ha) in t3 treatment (metro 70wg @ 750 gm ha-1 at sowing followed by irrigation) closely followed by treatment t5 while lowest yield 8.19 t/ha was recorded in t6 treatment (control). the maximum gross return was obtained from treatment t4 which was at par with treatment t5. similar trend was followed in case of gross margin but higher cost was involved in this treatment. as a result, bcr was higher int4 which was closely followed by t5 (table 2). 111 effect of different doses of herbicide on weed control in maize field table 2. grain yield, cost and benefit analysis of maize as influenced by different weed control management practice (across the location) treatments grain yield (t/ha) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr 1 2 3 4=1/2 t1 8.61 107,000 92,300 14,700 1.16 t2 8.82 111,000 92,500 18,500 1.20 t3 9.44 114,400 92,700 21,700 1.23 t4 8.61 116,600 92,900 23,700 1.26 t5 9.37 118,300 95,000 23,300 1.24 t6 8.19 95,000 89,900 5,100 1.06 lsd (0.05) 0.48 cv(%) 3.04 t1) metro 70wg @ 250 gm/ha, t2) metro 70wg @ 500 gm/ha, t3) metro 70wg @ 750 gm/ha, t4) weed free, t5) two hand weeding at 20 das and 35 das, t6) control (untreated) among the weed species, echinochola crusgalli (shama) was found dominant in maize field. hand weeding is the best option for controlling of weeds in maize field. but in labor scarce situation, herbicide metro 70wg @ 750 gm ha-1 (at sowing followed by irrigation) can be suggested for reasonable yield of maize with reduced weed infestation. references paul. s. k., s. mazumder, t. a. mujahidi, s. k. roy and s. kundu. 2015. optimization of herbicide teana 9 ec dose for controlling weeds in brinjal. bangladesh agron. j., 18(1): 113-119. paul. s. k., t. a. mujahidi, m. m. h. khan, s. k. roy and m. m. rahman. 2014. determination of weed infestation and optimum dose of herbicide (teana 9 ec) to control weeds in wheat field. bangladesh j.weed sci,. 4 & 5: 93-99. turk, m. a. and tawaha, a. r. m. (2002). effects of sowing rates and weed control methods on winter wheat under mediterranean environment. pakistan j. agron.16(4): 461-464. evaluation of locally improved rice varieties for nitrogen use efficiency bangladesh agron. j. 2016, 19(2): 39-49 yield and nitrogen use efficiency of locally improved rice varieties in rice based tidal flooded ecosystem of bangladesh m. a. a. mamun1*, m. m. haque1, q. a. khaliq1, m. a. karim1, a. j. m. s. karim1, a. j. mridha2 and m. a. saleque2 1bangabandhu sheikh mujibur rahman agricultural university, gazipur 1706, bangladesh 2bangladesh rice research institute, gazipur 1701, bangladesh *corresponding address: aamamunbrri@yahoo.com key words: grain yield, nitrogen uptake, nitrogen harvest index, rice cultivars, tidal ecosystem abstract an on farm field experiment was conducted to evaluate locally improved aman rice varieties in terms of nitrogen use efficiency and grain yield in southern region of bangladesh. the treatments were: i. deep placement of urea (udp) before panicle initiation stage and ii. farmers’ practice (fp/control). the locally popular rice varieties were used as planting materials. higher panicles m-2 and grains panicle-1 was obtained from udp application compared to fp. nitrogen fertilization increases grain and straw nitrogen content significantly. application of urea before panicle initiation stage gave considerable higher grain yield in all cultivated varieties. cultivated aman varieties produced 2.0 to 2.5 t ha-1 grain without application of n fertilizer. but, cultivated local variety razashail, kutiagoni, sadachikon, sadapajam, lalmota and sadamota gave 3.0 to 3.5 t ha-1 grain in tidal prone areas with udp. hence, application of urea gave yield advantage by 0.5 to 1.0 t ha-1. the highest internal, agronomic, recovery and physiological efficiency; nitrogen harvest and grain yield efficiency index was obtained from kutiagoni, lalpayka, sadachikon, sadapajam, moulata and lalmota. based on the yield and nitrogen fertilizer use efficiency, it could be concluded that udp before panicle initiation stage is an effective option of urea application for rice cultivation in tidal prone areas. introduction tidal flooded ecosystem is one of the major unfavorable agro-ecological situations (hossain et al., 2002) for crop cultivation. around 1.0 million hectare of land is tidal prone in southern region (elahi et al., 2001) of bangladesh. the hydrology of this area influences the agricultural ecosystem, cropping system and farmers socioeconomic condition. aman rice is the major crop in tidal prone areas in bangladesh. farmers do not apply fertilizer especially nitrogen (n) in aman season in tidal areas because there is a high risk of surface losses to floodwater. as a result, the yield of cultivated local varieties is low. on the other hand, application of n increases grain and straw yield as well as n use efficiency (hassan et al., 2009). nitrogen is considered as the most important nutrients in improving rice yields under most agro-ecosystem (fageria and santos, 2014). however, nitrogen can improve leaf n concentration, photosynthetic rate, delay in leaf senescence, and increase in the amount of dry matter for grain filling, thus improve the productivity of rice (mnzava, 2002). moreover, n is responsible for improving panicle size (increase number of filled grains panicle-1) and grain weight and responsible for reducing spikelet sterility (fageria, 2009). hence, the efficient use of n can increase grain yield through improving panicle number, thousand grain weights and reducing sterility percent (fageria, 2007). thus, a mailto:aamamunbrri@yahoo.com 40 mamun et al. suitable n management technique is needed which will increase the grain fertility, reduce spikelets sterility and improve rice grain yield in tidal flood prone areas. top dressing of prilled (pu) and deep placement (udp) of urea super granule (usg) are the two methods of n fertilization in bangladesh. in tidal flooded areas, surface application of n fertilizer like pu is not possible due to high risk of surface loss (rochette et al., 2013). but, deep placement of urea reduces n concentration in the floodwater; thus, it reduces n loss and increases uptake by the rice plant. deep placement of urea increases n use efficiency up to 50 to 70%, increases grain yield by 15 to 20%, and reduces fertilizer n use by 30 to 40% (alam et al., 2013; ifdc, 2013). therefore, deep placement of urea may a good alternative for efficient n use and higher yield of rice in tidal flooded areas. this would restrict the vigorous vegetative growth and preventing lodging of the crop. the objective of this study was to evaluate locally improved aman rice varieties in terms of yield and nitrogen use efficiency in tidal ecosystem of bangladesh. materials and methods locations a farmer participatory field experiment was conducted at gournadi, bakergonj of barisal and batagi under borguna district. the area covers southern part of the country belongs to agro ecological zone-13 named ganges tidal floodplain. the experiment was conducted during july to december, 2013. only urea super granule (usg of 1.8g size) applied in treatment plots. no fertilizer was applied in farmers practice (fp) plot. locally popular aman varieties were used as planting materials. the urea super granule (usg) was applied at first week of september to october (before pi). as the site of experiment was flooded daily, usg was applied after recession of tidal water. the experiment is laid out in split plot design with three replications (table 1). fig. 1. depth of tidal water enter into the crop fields table 1. the detail treatments for farmers’ participatory field trials 0 10 20 30 40 50 60 70 80 90 10 .ju l 20 .ju l 30 .ju l 10 .a ug 20 .a ug 30 .a ug 10 .s ep 20 .s ep 30 .s ep 10 .o ct 20 .o ct 30 .o ct 10 .n ov 20 .n ov 30 .n ov 10 .d ec 20 .d ec 30 .d ec dates of month w at er d ep th ( cm ) gournadi bakergonj batagi 41 yield and nitrogen use efficiency of locally improved rice varieties in rice based locations factor a (rice variety) factor b (nitrogen) gournadi, barisal i. razashail, ii. kutiagoni, iii. lalpayka, iv. sadachikon, v. mutha, vi. lalchikon, vii. lothor, viii. sadapajam i. deep placement of urea (udp) super granule before panicle initiation (pi) stage, and ii. no fertilizer (control) bakerganj, barisal i. sadamota ii. lalmota iii. moulata i. udp before pi stage, and ii. no fertilizer (control) betagi, barguna i. sadamota ii. lalmota iii. moulata i. udp before pi stage, and ii. no fertilizer (control) the panicle numbers were determined from 16 hill sample at harvesting. the grains were separated and counted following standard procedures (yoshida et al., 1976). rice plants from 5 m2 area of the middle of each plot were harvested at ground level and threshed. the grains were dried in sunlight and winnowed before weighing and the seed yield was adjusted to 14% moisture content. grain and straw nitrogen was determined from the collected plant samples by micro kjeldahl method (yoshida et al., 1976). the efficiency of applied n and n taken up by the rice crop were assessed using the following five different indices (dobermann and fairhurst, 2000). a. agronomic efficiency (ae): ae is the kg grain yield increase kg-1 n applied. aen = (gy+ n gy0n) / fn; where, aen = ae of n; gy+ n = grain yield due to addition of fn; gy0 n = grain yield without addition of n; fn = amount of n applied (kg ha-1). b. recovery efficiency (re): re is the kg n taken up by the crop kg-1 n applied. ren = (un+ n un0n) / fn; where, ren = re of n; un+ n = plant n uptake with addition of fn; un0 n = plant n uptake without addition of n; fn = amount of n applied (kg ha-1). c. physiological efficiency (pe): pe is the kg grain yield increase kg-1 n taken up. pen = (gy+ n – gy0 n) / (un+ n – un0 n); where, pen = physiological efficiency of n; gy+ n = grain yield due to addition of fn; gy0n = grain yield without addition of n; un+ n = plant n uptake with addition of fn; un0n = plant n uptake without addition of n. d. partial factor productivity (pfp): pfp is the kg grain yield kg-1 n applied. pfpn = gy+ n / fn; where, pfpn = pfp of n; gy+ n = grain yield due to addition of fn; fn = amount of n applied (kg ha-1). e. internal efficiency (ie): ie is the kg grain yield kg-1 n taken up. ien = gy / un; where, ien = internal efficiency of n; gy = grain yield (kg ha -1); un = total n uptake (kg ha-1). f. nitrogen harvest index (nhi): nitrogen harvest index is defined as the ratio between nitrogen (n) uptake in grain and n uptake in grain plus straw or shoot. nitrogen harvest index = nitrogen uptake in grain / nitrogen uptake in grain and shoot g. grain yield efficiency index (gyei): grain yield is the best measure of a genotype evaluation in a screening (fageria and santos, 2014). gyei = (gy1 / ayg1) × (gy2 / agy2) where, gy1 = grain yield at control, agy1 = average grain yield of genotypes at control, gy2 = grain yield at n applied and agy2 = average grain yield of 42 mamun et al. genotypes at n applied. genotypes having gyei values >1.0 were classified as efficient, genotypes which were having gyei between 0.5 to 1.0 were classified as moderately efficient and those with gyei values <0.5 were classified as inefficient. data analysis record data were analyzed statistically using mstat-c (russell, 2010) package and difference among the treatment means were adjust using duncan’s multiple range tests (gomez and gomez, 1984). results and discussion yield contributing attributes and grain yield urea super granule (usg) applied plot produced higher number of panicles m-2. the highest number of panicles m-2 was obtained from lothor, lalmota and moulata at gournadi, bakergonj and batagi, respectively (table 2, 3 & 4). sadapajam at gournadi, moulata at bakergonj and sadamota at batagi produced the highest number of grains panicle-1 (table 2, 3 & 4). the farmer’s practice plot produced the lowest number of grains panicles-1 and panicles m-2 in all locations. at gournadi, the maximum grain yield was recorded from sadachikon followed by sadapajam variety with usg application (table 2). these two varieties gave more than 4.5 t ha-1 grain with n application. at bakergonj, numerically maximum grain yield was recorded from lalmota variety with usg application (table 3). this variety produced 3.35 and 2.45 t ha-1 with n and control, respectively. at batagi, numerically maximum grain yield was recorded from lalmota variety with n-application (table 4). the application of usg gave 0.5 to 1.0 t ha-1 yield advantages compared to farmer’s practice in all locations. in this study, higher number of panicles m-2 and grains panicles-1 were obtained from the addition of n compared to control (tables 2 to 4). more number of panicles might be due to the more availability of nitrogen that played a vital role in cell division. these results are in accordance to the findings of rajput et al. (1988). it was demonstrated that the deep placement of urea (n) before panicle ignition stage of rice exerted significant effects on grain yield. at gournadi, sadapajam produced grain yield by 4.66 and 3.27 t ha-1 with addition of n and control, respectively (table 2). table 2. effect of urea deep placement on yield components of aman rice, gournadi, barisal. varieties panicles m-2 grains panicle-1 grain yield (t ha-1) n-applied control n-applied control n-applied control razashail 159 a 142 d 90 c 75 b 3.59 b 2.80 b kutiagoni 172 ab 151 bcd 90 c 79 b 3.85 b 3.35 b lalpayka 151 bcd 127 e 91 c 77 b 3.24 bc 2.19 bc sadachikon 150 bcd 138 de 143 b 135 a 4.74 a 4.44 a mutha 155 bc 127 e 93 c 70 b 3.59 b 2.10 bc lalchikon 179 ab 136 de 78 c 74 b 3.04 bc 2.18 bc lothor 189 a 172 ab 77 c 64 b 2.63 c 2.11 bc sadapajam 155 bcd 101 f 172 a 150 a 4.66 a 3.27 b average 164 a 137 b 104 a 91 b 3.67 a 2.81 b variety (v) ns * * nitrogen (n) ** ** ** v × n ** * * cv (%) 12.5 16.3 12.8 43 yield and nitrogen use efficiency of locally improved rice varieties in rice based figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. thus, this variety produced 42% more grain yield with addition of n compared to control. the cultivated local varieties, razashail, kutiagoni and mutha produced more than 3.5 t ha-1 grains with addition of n. on the other hand, all the cultivated varieties except kutiagoni and sadapajam produced less than 2.0 t ha-1 in control plots (table 2). razashail variety gave 28% higher yield with addition of n than control. moreover, more than 1.0 t ha-1 yield advantages was obtained from local variety lalpayka, mutha and sadapajam with addition of n compared to control. at bakergonj, about 0.39 t ha-1 yield advantages was recorded from n plots which was 16% higher than fp plots in sadamota variety (table 3). at batagi, in n-applied plot, cultivated sadamota produced 3.43 t ha-1 which was 30% higher than fp plots (table 4). the improved yield contributing attributes, such as panicle m-2 and grains panicle-1 might be responsible for improved yield of rice (tables 2 to 4). fageria and santos (2014) reported that the low land rice genotypes gave significantly higher grain and yield, more panicles per unit areas and better root growth with the addition n. table 3. effect of urea deep placement on yield components of aman rice, bakergonj, barisal. varieties panicles m-2 grains panicle-1 grain yield (t ha-1) n-applied control n-applied control n-applied control sadamota 142 b 126 c 71 b 61 b 2.80 2.41 moulata 142 b 130 c 86 a 78 a 2.92 2.34 lalmota 158 a 138 bc 72 b 64 b 3.35 2.45 average 147 a 131 b 76 a 68 b 3.02 a 2.40 b variety (v) ns * ns nitrogen (n) ** ** ** v × n * * * cv (%) 12.5 12.5 12.8 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. table 4. effect of urea deep placement on yield components of aman rice, batagi, borguna. varieties panicles m-2 grains panicle-1 grain yield (t ha-1) n-applied control n-applied control n-applied control lalmota 177 ab 146 b 74 a 65 b 3.76 a 2.61 b moulata 185 a 172 a 72 a 63 b 3.05 a 2.54 b sadamota 172 b 144 b 68 b 64 b 3.43 a 2.40 b average 178 a 154 b 71 a 64 b 3.41 a 2.52 b variety (v) * ns ns nitrogen (n) ** ** ** v × n * ** * cv (%) 11.4 11.0 15.1 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. total nitrogen uptake at gournadi, the highest total n uptake was recorded from sdapajam when n applied (table 5). local varieties razashail, kutiagoni, lalpayka and lalchikon uptake 44 mamun et al. similar total n. the lowest n uptake at n applied plot was obtained in lothor. at bakergonj, the highest total n uptake was recorded from lalmota in both n and control. sadamota uptake total n by 57.25 and 43.25 kg n ha-1 with n and control, respectively (table 6). at batagi, the highest total n uptake was recorded from sadamota followed by lalmota when urea super granule was applied. in control plots, the highest total n was recorded from the variety moulata (table 7). deep placement of urea (n) exerted significant influence on total n uptake (tables 5 to 7). significantly higher amount of n was taken up by grain and straw due to application of urea in all varieties. at gournadi, 32.18 kg ha-1 more total n was taken up by addition of n which was 58% higher than that of control plot in razashail variety (table 5). table 5. effect of urea deep placement on internal efficiency of aman rice, gournadi, barisal varieties total n uptake (kg n ha-1) internal efficiency (kg grain kg-1 n) n-applied control n-applied control razashail 87.45 b 55.27 b 41.54 ab 50.78 ab kutiagoni 79.31 b 63.44 b 48.73 a 52.7 ab lalpayka 77.54 b 46.02 bc 41.8 ab 47.14 c sadachikon 103.95 a 77.89 a 45.62 a 57.07 a mutha 103.1 a 52.16 b 35.05 c 40.24 d lalchikon 86.58 b 50.77 bc 35.2 c 43.07 cd lothor 58.07 c 41.96 bc 45.41 a 50.31 bc sadapajam 106.51 a 58.03 b 43.78 a 56.45 ab average 87.81 a 55.69 b 42.14 b 49.72 a variety (v) * * nitrogen (n) ** ** v × n * ** cv (%) 15.1 8.2 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. table 6. effect of urea deep placement on internal efficiency of aman rice, bakergonj, barisal varieties total n uptake (kg n ha-1) internal efficiency (kg grain kg-1 n) n-applied control n-applied control sadamota 57.25 b 43.25 a 49.70 56.11 moulata 58.41 b 38.41 b 51.09 61.71 lalmota 69.07 a 47.08 a 49.05 51.82 average 61.58 a 42.91 b 49.95 b 56.55 a variety (v) * ns nitrogen (n) ** ** v × n ** * cv (%) 18.2 12 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. 45 yield and nitrogen use efficiency of locally improved rice varieties in rice based this means that the n applied at late growth stage of rice was absorbed by the grain and straw. fageria and baligar (1999) also reported that n applied late during the reproductive growth stage absorbed by the crop and improve grain yield. table 7. effect of urea deep placement on internal efficiency of aman rice, batagi, borguna varieties total n uptake (kg n ha-1) internal efficiency (kg grain kg-1 n) n-applied control n-applied control lalmota 62.24 36.21 60.35 72.51 moulata 53.39 39.35 57.51 66.26 sadamota 62.75 37.43 54.87 64.11 average 59.46 a 37.66 b 57.58 b 67.63 a variety (v) ns ns nitrogen (n) * ** v × n * * cv (%) 16.1 13.8 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. ns = not significant. nitrogen use efficiency and partial factor productivity the internal efficiency (ie) was higher in control than n applied plot in all varieties. at gournadi, kutiagoni gave the highest internal efficiency in n applied plot (table 5). at bakergonj, moulata gave the ie in n applied plots (table 6). at batagi, among the cultivated varieties lalmota gave the highest ie in n plots (table 7). at gournadi, the highest agronomic efficiency (ae) was recorded from mutha followed by sadapajam (table 8). at bakergonj, the highest ae of n was recorded from lalmota (table 9). at batagi, statistically the highest ae of urea was recorded from sadamota followed by lalmota. the lowest ae was recorded from moulata were (table 10). at gournadi, the highest partial factor productivity (pfp) was recorded from sadapajam in gournadi (table 8). rest of the varieties gave less than 200 kg grain kg-1 n as pfp. at bakergonj, the highest pfp of urea was recorded from lalmota (table 9). at batagi, the highest pfp of urea was recorded from sadamota. the pfp of rest two varieties like lalmota and moulata were 198.76 and 172.33 kg grain kg-1 n (table 10). at gournadi, recovery efficiency (re) of n application was significantly (p<0.05) influenced by cultivated varieties in all locations (table 8). the lowest re was obtained from kutiagoni and lothor. at bakergonj, the highest re of urea was recorded from lalmota followed by moulata (table 9). the lowest re was obtained from sadamota (9.24 kg grain kg-1 n uptake). at batagi, significantly the highest re was recorded from sadamota which was statistically significantly with that of lalmota (table 10). cultivated varieties influenced (p<0.05) physiological efficiency (pe) of n (table 8). the highest pe of n was recorded from lothor followed by lalpayka in gournadi. these two varieties gave pe by more than 30 kg grain kg-1 n uptake. at bakergonj, the highest pe of urea was recorded from lalmota (table 9). at batagi, the highest pe of urea was recorded from lalmota followed by sadamota (table 10). application of n in the root zone areas increased grain yield over no fertilization in rice is already well-well documented (alam et al., 2013). deep placement of n remain in soil for longer time which ensure continuous n supply to the crop throughout the life cycle and increases grain yield and use efficiency. fageria and baligar (2001) reported that physiological efficiency was 146 kg biological yield per unit of n accumulated in 46 mamun et al. flooded rice cultivar metica 1. singh et al. (1998) reported an n recovery efficiency of 37% in 20 low land rice genotypes. furthermore, nitrogen recovery efficiency for lowland rice is less than 50% (fageria and baligar, 2005). a flooded rice variety, metica 1, from south america showed an average ue of 58 kg kg-1 across n rates (fageria and baligar, 2001). yoshida (1981) also reported that the efficiency of utilization for grain production in the tropics is about 50 kg grain per kg n absorbed and this efficiency appears to be almost constant regardless of the rice yields achieved. agronomic efficiency in low land rice in the tropics is reported to be in the range of 15 to 25 kg grain produced per kg of applied n (yoshida, 1981). physiological n use efficiency varied from 11.41 to 32.64, 32.50 to 42.37 and 35.80 to 41.67 kg kg-1 at gounadi, bakergonj and batagi, respectively. fageria and baligar (2001) reported that physiological efficiency was 146 kg biological yield per unit of n accumulated in flooded rice cultivar metica 1. table 8. variety wise n use efficiencies of urea super granule application, gournadi, barisal varieties agronomic efficiency (kg grain kg-1 n) partial factor productivity (kg grain kg-1 n) recovery efficiency (%) physiological efficiency (kg grain kg-1 n) razasail 40.55 c 188.81 b 16.63 d 20.8 c kutiagoni 26.18 d 199.60 b 8.4 e 28.36 ab lalpayka 52.39 c 169.31 c 15.84 d 30.98 a sadacikon 12.5 e 199.18 b 10.94 e 11.41 d mutha 79.82 a 188.47 b 27.58 a 29.63 a lalcikon 46.3 c 164.01 c 19.27 c 24.03 c lothor 25.85 d 129.62 d 7.92 e 32.64 a sadapajam 68.22 b 229.29 a 23.84 b 28.62 ab average 43.98 183.54 16.30 25.81 f-test ** ** ** * cv (%) 23.7 25.5 26.7 27.6 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. table 9. variety wise n use efficiencies of urea super granule application, bakergonj, barisal varieties agronomic efficiency (kg grain kg-1 n) partial factor productivity (kg grain kg-1 n) recovery efficiency (%) physiological efficiency (kg grain kg-1 n) sadamota 25.94 c 185.40 b 9.24 b 33.99 b moulata 39.38 b 197.07 b 14.11 a 32.50 b lalmota 60.35 a 230.88 a 14.83 a 42.37 a average 41.89 204.45 12.73 36.29 f-test ** * ** * cv (%) 27.5 30.3 29.3 32.2 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. 47 yield and nitrogen use efficiency of locally improved rice varieties in rice based table 10. variety wise n use efficiencies of urea super granule application, batagi, borguna varieties agronomic efficiency (kg grain kg-1 n) partial factor productivity (kg grain kg-1 n) recovery efficiency (%) physiological efficiency (kg grain kg-1 n) lalmota 56.25 b 198.76 b 13.40 b 41.67 a moulata 27.73 c 172.33 c 7.97 c 35.80 b sadamota 66.01 a 221.47 a 16.81 a 41.18 a average 50.00 197.52 12.73 39.55 f-test * ** * * cv (%) 20.1 22.1 24.2 24.3 figures with same letters did not differ significantly. * and ** significant at 5 and 1% level. nitrogen harvest index and grain yield efficiency index at gournadi, the maximum n harvest index was obtained from kutiagoni which was statistically identical with lalpayka, sadachikon and sadapajam (table 11). at bakergonj, the n harvest index was obtained from moulata followed by other two varieties (table 12). on the other hand, the n harvest index was recorded from lalmota amd moulata at batagi (table 13). at gournadi, the highest grain yield efficiency index was obtained from sadachikon followed by sadapajam (table 11). table 11. grain yield efficiency index of local aman rice, gournadi, barisal varieties n harvest index grain yield efficiency index value comments razashail 0.69 ab 1.05 c efficient kutiagoni 0.76 a 1.39 b efficient lalpayka 0.73 a 0.78 d moderately efficient sadachikon 0.71 a 1.69 a efficient mutha 0.68 bc 0.79 d moderately efficient lalchikon 0.63 bc 0.69 d moderately efficient lothor 0.68 bc 0.58 d moderately efficient sadapajam 0.75 a 1.59 ab efficient f-test * * cv (%) 5.5 11.8 figures with same letters did not differ significantly. * significant at 5% level. table 12. grain yield efficiency index of local aman rice, bakergonj, barisal varieties n harvest index grain yield efficiency index value comments sadamota 0.62 c 0.95 b moderately efficient moulata 0.65 a 0.95 b moderately efficient lalmota 0.63 b 1.13 a efficient f-test * ** cv (%) 10.7 12.03 figures with same letters did not differ significantly. * significant at 5% level. 48 mamun et al. at bakergonj and batagi, the highest grain yield efficiency index was obtained from lalmota (table 12 and 13). lalmota was efficient in both locations. rattunde and frey (1986) reported that the n harvest index was positively associated with grain yield of oats and response of grain yield. similarly, kairudin and erey (1988) also reported that n harvest index of oats was positively correlated with grain yield and gross protein yield in low and high n. table 13. grain yield efficiency index of local aman rice, batagi, borguna varieties n harvest index grain yield efficiency index value comments lalmota 0.65 a 1.24 a efficient moulata 0.64 a 0.97 b moderately efficient sadamota 0.62 b 1.02 b efficient f-test ** * cv (%) 7.1 17.2 figures with same letters did not differ significantly. * significant at 5% level. conclusion results of this study showed that cultivated aman varieties produced 2.0 to 2.5 t ha-1 grain without application of n fertilizer. but, local variety razashail, kutiagoni, sadachikon, sadapajam, lalmota and sadamota varieties gave 3.0 to 3.5 t ha-1 grain in tidal prone areas with the deep placement of urea super granule (usg). similarly, the highest internal, agronomic, recovery and physiological efficiency; nitrogen harvest and grain yield efficiency index was obtained from kutiagoni, lalpayka, sadachikon, sadapajam, moulata and lalmota. thus, application of usg before panicle initiation stage is an effective option for urea application in tidal prone areas. references alam, m. m., m. r. karim and j. k. ladha. 2013. integrating best management practice for rice with farmers’ crop management techniques: a potential option for minimizing rice yield gap. field crops res. 144: 62-68. fageria, n. k. and a. b. santos. 2014. lowland rice genotypes evaluation for nitrogen use efficiency. j. plant nutr. 37(9): 1410-1423. dobermann, a. and t. fairhast. 2000. rice: nutrient disorders and nutrient management. oxford graphic printers pte ltd. pp. 1-191. elahi, n. e., m. a. h. khan, m. a. i. khan, m. r. islam, m. a. salam, m. a. hossain and a. u. ahmed. 2001. research report of the tidal non-saline sub-ecosystem for the year 2001. ifad planning meeting held on 13 january, 2001, dhaka, bangladesh. fageria, n. k. 2009. the use of nutrients in crop plants. boca raton, fl: crc press. fageria, n. k. and baligar, v. c. 1999. yield and yield components of lowland rice as influenced by timing of nitrogen fertilization. j. plant nutr. 22: 23-32. fageria, n. k. (2007). yield physiology of rice. j. plant nutr. 30: 843-879. fageria, n. k. and v. c. baligar. 2001. lowland rice response to nitrogen fertilization. commun. soil sci. plant anal. 32: 1405-1429. 49 yield and nitrogen use efficiency of locally improved rice varieties in rice based fageria, n. k. and v. c. baligar. 2005. enhancing nitrogen use efficiency in crop plants. adv. agron. 88: 97-185. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research (2nd edn.). john willey and sons, singapore. pp. 28-192. hassan, m. s., a. khair, m. m. haque, a. k. azad and a. hamid. 2009. genotypic variation in traditional rice varieties for chlorophyll content, spad value and nitrogen use efficiency. bangladesh j. agril. res. 34(3): 505-515. hossain, m. a., b. c. roy, s. s. haque, m. a. i. khan and a. w. julfiquar. 2002. potentiality of hybrid rice in the south central region of bangladesh. hybrid rice in bangladesh, progress and future strategies. bangladesh rice research institute, pp: 51-52. ifdc. 2013. fertilizer deep placement. ifdc solutions. int. fertilizer development center, muscle shoals, al. http://issuu.com/ifdcinfo/ docs/fdp_8pg_final_web. kairudin, n. m. d. and k. j. frey. 1988. soil n availability and nitrogen harvest index of oats. j. iowa acad. sci. 95: 73-78. mnzava, m. m. w. 2002. nitrogen absorption rate at different growth stages in relation to grain production of lowland rice. ph.d. thesis, los banos, philippines: university of philippines. rajput, m. k. k., a. h. ansari, s. mehdi and a. m. hussain. 1988. effect of n and p fertilizers alone and in combination with om on the growth and yield of toria. sarhad j. agri. res. 4: 3-6. rattunde, h. f. and k. j. frey. 1986. nitrogen harvest index in oats: its repeatability and association with adaptation. crop sci. 26: 606–610. russell, d. 2010. mstat-c. design, management and statistical tool. plant and soil science. michigan state university. 384c east lansing, mi 48824. rochette, p., d. a. angers, m. h. chantigny, m. o. gasser, j. d. mac-donald, d. e. pelster and n. bertrand. 2013. ammonia volatilization and nitrogen retention: how deep to incorporate urea? j. environ. qual. 42: 1635–1642. singh, u., j. k. ladha, e. g. castillo, g. punjalan, a. tirol-padre and m. duquesa. 1998. genotypic variation in nitrogen use efficiency in medium and long duration rice. field crop res. 58: 35-53. yoshida, s. 1981. fundamentals of rice crop science. irri, los banos, philippines. p. 269. yoshida, s. and v. coronel. 1976. nitrogen nutrition, leaf resistance, and leaf photosynthetic rate of the rice plant. soil. sci. plant nutr. 22: 207-211. http://issuu.com/ifdcinfo/ bangladesh agron. j. 2019, 22(2): 83-89 genotype and sowing date effects on seed yield of olitorius jute in late season a.t.m.m. alam and m.m. haque1 principal scientific officer bangladesh jute research institute, manik mia avenue, dhaka-1207 1professor, bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 corresponding e-mail: morshedbjri@gmail.com (received: 06 january 2020, accepted: 11 february 2020) keywords: genotype, sowing date, seed yield, jute, late season abstract feld experiments were conducted at four locations of bangladesh (manikgonj, cumilla, dinajpur and joshore) to optimize sowing date for higher seed yield of jute in late sown condition. the experimental variables constituted with three genotypes (o-72, o-3820 and acc.4311) and three sowing dates (31 july, 15 august and 30 august).each experiment was laid out in a randomized complete block design with three replications. the treatment combinations were assigned randomly and afresh randomization was followed in each replication. results showed that the genotype acc.4311, o-72 and o3820 produced maximum number of branches (5.40, 4.90 and 4.40, respectively) plant-1 on 15 august sowing at manikgonj. the genotype acc.4311 produced higher number of pods plant-1 than other two genotypes (o-72 and o-3820) in all sowing dates andat all the locations. the highest number of seedspod-1 (220.80) was found from the genotype acc.4311grown at manikgonj which was statistically similar (196.90) with that of the same genotype sown on the same date at joshore. the highest thousand seed weight (2.478 g) was recorded from the seeds of genotype acc.4311 sown on 15 august at manikgonj followed by same genotype at joshore.finally, the genotype acc.4311 sown on 15 august produced the highest seed yield (2.478 t ha-1) at manikgonjwhich was significantly higher than those of sown on 31 july and 30 august at the same location. as the genotype acc.4311 was found outstanding sown on 15 august over locations, this genotype may be considered promising for higher seed yield of olitorius jute in late season. introduction jute is the prime fibre crop in bangladesh although its productivity is much low due to varied reasons. one of the key reasons is use of poor quality seed. high quality jute seed can be produced by sowing the crop in optimum time. sowing time is one of the important production components and sowing before or after optimum date produces lower yield with poor seed quality. sowing time is specifically important for late sown jute as it is short day photoperiod sensitive. the critical photoperiod of corchorusolitorius l. is 12.5 hours (johansen et al., 1985) although it may vary over the genotypes and other environmental parameters prevailing during whole growing season. extreme late sowing, short photoperiod hastens flowering, reduces seed maturation period and provides adverse effect upon seed quality. because of late sowing, temperature below 150c usually causes flower bud injury, restricts its number and affects on pod formation (hossain etal., 1999). further, high temperature convergently hastens maturity of seeds; pods turn brown and dry quickly before seeds attain proper physiological maturity. these plants produced more unfilled seeds with smaller seed size and low 86 alam et al. germination percentage. at extreme early sowing, anthesis period is prolonged (talukder and akanda, 1994), but there is every possibility to damage seed crop by natural hazards during rainy season. seed quality of jute further depends on harvesting stage of the crop. harvesting the crop at an early stage makes relative losses due to threshing and gives enormous unfilled seeds. besides, mature seeds store better than the immature seeds. harvesting at a late stage may result in increased weather damage and losses due to shattering of seeds. further, prevalence of weather damage is frequent in early planted crop, still, persistent foggy weather affects late jute seed crop and often contains pathogens and deteriorates health status of seed (islam et al., 2007). as sowing time regulates appropriate stage of seed maturity,the present study was undertaken to optimize sowing date for higher seed yield of different genotypes of jute in late sown condition. materials and methods field experiments were conducted at four locations of bangladesh viz. jute agriculture experimental station, manikgonj; jute research regional station, chandina, cumilla; jute seed production andresearch station, noshipur, dinajpur and jute research sub station, monirampur, joshore during 2011-12 late jute seed growing season. the climate of the experimental site was sub-tropical in nature having very little rainfall in the mid october and mid november with gradual fall in temperature from last week of october. treatments consisted of three genotypes which were evaluated at three sowing dates (31 july, 15 august and 30 august) over four locations. among these three genotypes, o-72 was a released variety but o-3820 and acc.4311 were advanced breeding lines. the experiment was laid out in a randomized complete block design with three replications. the treatment combinations were assigned randomly and afresh randomization was followed in each replication. the size of each unit plot was 3 m x 3 m. each unit plot and blocks were separated by 1.0 m and 2.0 m, respectively. at each location and each sowing date, seeds were sown in lines at the rate of 3.0 kg ha-1 in 30 cm apart furrows made with country plough. seeds were then properly covered with soil. the crop was fertilized with urea, triple super phosphate, muriate of potash, gypsum and zinc sulphate at the rate of 200, 100, 60, 100 and 10 kg ha-1 as per recommendation of bjri (2006). one third of urea and whole amount of other fertilizers were applied as basal during final land preparation and rest of the nitrogen was top dressed in two equal splits at 20 and 40 days after sowing. first weeding and thinning were done at 25 days after sowing when the plants attained a height of about 8 to 10 cm. second weeding was done at 45 days after sowing just before the top dressing of urea. miticide, insecticide and fungicide were sprayed as precautionary measure by using recommended doses to protect the crop from insect-pests. for determination of yield contributing characters of jute seed crop, ten plants were randomly selected from each plot and branch plant-1, pod plant-1, seed pod-1 and 1000 seed weight were recorded. for yield, the crop was harvested by whole plot basis and dried in the sun for 5 days. jute seeds were then threshed out by beating the pods with bamboo stick. it was cleaned and dried in the sun on the cemented floor. yield of jute seed was converted into kg ha-1 at 9% moisture content. all data were subjected to statistical analysis by analysis of variance (anova). microsoft excel and mstat software programs were used wherever appropriate and the means were compared according to duncan’s multiple range test (gomez and gomez, 1984). functional relationships among the parameters were established through correlation and regression analysis. resultsand discussion yield attributes and seed yield genotype and sowing dates interacted significantly in yield components and seed yield of late season jute and accordingly those parameters were discussed in subsequent headings. genotype and sowing date effects on seed yieldof jute 87 number of branch number of branch plant-1of jute was significantly influenced by sowing date (table 1). the genotype acc.4311, o-72 and o-3820 produced maximum number of branches (5.40, 4.90 and 4.40, respectively) plant-1 on 15 august sowing at manikgonj. the intermediate number of branches plant1(4.90, 4.40 and 3.80, respectively at manikgonj; 4.50, 4.00 and 3.50, respectively at joshore; 4.30, 3.80 and 3.30 respectively at dinajpur and 3.70, 3.20 and 3.00, respectively at cumilla) were observed in crops sown on 31 july and the lowest number of branches plant-1(3.60, 3.20 and 2.70, respectively at manikgonj; 3.20, 2.70 and 2.20, respectively at joshore; 2.30, 2.40 and 2.80 respectively at cumilla; 1.80, 1.90 and 2.30, respectively at dinajpur) were found from the crops sown on 30 august. the branching of jute plant occurred normally through bifurcation of plant top at the time of flower bud induction. branching also occurs when plant top get injured at the early stage of the crop. at present study, the crops of 15 august sowing might have chances of producing higher number of branches because of better interception of sunlight and soil moisture and thus provided maximum number of branches plant-1. table 1. interaction effect of genotype and sowing dates on the number of branch plant-1of olitorius jute seed crop at four locations treatments locations genotypes sowing dates manikgonj cumilla dinajpur joshore o-72 31 july 4.40 ca 3.20 cdc 3.80 bb 4.00 ca 15 august 4.90 ba 4.00 bb 3.30 cdc 4.40 bcb 30 august 3.20 ea 2.40 efb 1.90 efc 2.70 eb o-3820 31 july 3.80 da 3.00 dc 3.30 cdbc 3.50 dab 15 august 4.40 ca 3.50 cb 3.00 dc 4.20 bca 30 august 2.70 fab 2.80 dea 2.30 ebc 2.20 fc acc.4311 31 july 4.90 ba 3.70 bcc 4.30 ab 4.50 bab 15 august 5.40 aa 4.50 ab 3.80 bc 5.10 aa 30 august 3.60 dea 2.30fb 1.80 fc 3.20 da means in a column followed by same small letter and in a row by same capital letter did not differ significantly by dmrt at 0.05 level. number of pods number of pods plant-1of olitorius jute resembled to that of branch number and it was higher in mid august sowings. in respective of genotypes, the highest number of pods plant-1was observed from the plants sown on 15 august sowing at all locations except dinajpur (table 2). the genotype acc.4311 produced higher number of pods plant-1than other two genotypes (o-72 and o3820) in all sowing dates andat all the locations. the genotype acc.4311 produced the highest number of pods (43.20) plant-1on 15 august sowing at manikgonj and it was followed by the number of pods plant-1in the same sowing date at joshore (37.10), cumilla (33.80) and dinajpur (27.80). the intermediate number of pods plant-1(37.20, 31.50 and 25.60, respectively at manikgonj; 33.30, 28.80 and 21.50 respectively at joshore and 31.50, 25.10 and 18.90 respectively at cumilla) were observed in crops sown on 31 july for all genotypes at all the locations except dinajpur. at dinajpur, higher number of pods plant-1was obtained from the crops sown on 31 july for all genotypes and it decreased gradually with later sowings. the crops sown on 15 august had higher number of branches plant1which might be contributed to produce higher number of pods plant-1as there is positive relationship between branch number and numerof pods plant-1of jute (figure1). the findings also accord with those of other authors (talukder and hossain, 1989; khanet al.,1997) who reported that number of branch of jute is the main reason of increasing number of pods plant-1of jute. 86 alam et al. table 2. genotype and sowing date effects on the number of pods plant-1 of olitorius jute seed crop at four locations treatments locations genotypes sowing dates manikgonj cumilla dinajpur joshore o-72 31 july 31.50 ca 25.10 bb 28.20 abab 28.80 bcab 15 august 37.60 ba 31.50 ab 25.50 bcc 31.80 bb 30 august 21.30 dea 15.50 debc 13.10 dc 19.20 dab o-3820 31 july 25.60 da 18.90 cdb 24.80 bca 21.50 cab 15 august 31.80 ca 25.30 bb 22.10cb 25.90 cb 30 august 18.10 ea 13.50 eb 14.90 dab 13.80 eb acc.4311 31 july 37.20 ba 31.50 ab 31.30 ab 33.30 abab 15 august 43.20 aa 33.80 ab 27.80 abc 37.10 ab 30 august 23.80 da 18.20 cdbc 14.70 dc 20.70 dab means in a column followed by same small letter and in a row by same capital letter did not differ significantly by dmrt at 0.05 level. fig. 1. relationship between number of branch and pods plant-1of olitorius jute seed crop produced at four locations. y = 9.435x 9.091 r² = 0.984 10 15 20 25 30 35 40 45 50 1 2 3 4 5 6 y = 9.415x 7.058 r² = 0.838 10 15 20 25 30 35 40 45 50 1 2 3 4 5 6 y = 7.482x 0.373 r² = 0.975 10 15 20 25 30 35 40 45 50 1 2 3 4 5 6 y = 7.920x 3.956 r² = 0.944 10 15 20 25 30 35 40 45 50 1 2 3 4 5 6 manikgonj cumilla dinajpur joshore n u m b er o f p od s pl an t-1 branch number plant-1 genotype and sowing date effects on seed yieldof jute 87 number of seeds number of seeds pod-1 of tossa jute was also significantly affected due to the interaction of genotype and sowing date at different locations. results revealed that number of seeds pod-1was the highest in crops sown on 15 august in all the genotypes (table 3). as the number of seeds pod-1mostly depends on pod length and pod diameter (alamet al., 2009), and the genotypes o-72, o-3820 and acc.4311 gave higher number of seeds pod-1, which might be the resultant of long pod length of those genotypes. table 3. effect of genotype and sowing dates on the seedsnumber pod-1of jute at four locations treatments locations genotypes sowing dates manikgonj cumilla dinajpur joshore o-72 31 july 168.50 cda 143.40 cdb 150.90 bb 155.40 cab 15 august 195.80 ba 170.50 bb 140.70 cdc 178.90 bb 30 august 145.30 ea 120.30 efb 110.60 eb 124.10 efab o-3820 31 july 154.40 dea 133.30 deb 148.00 bca 140.60 dab 15 august 172.30 ca 152.80 cb 133.50 dc 169.00 ba 30 august 135.70 ea 115.10 fb 117.80 eb 114.20 fb acc.4311 31 july 192.70 ba 169.10 bb 165.30 ab 172.40 bb 15 august 220.80 aa 188.90 ab 157.30 abc 196.90 ab 30 august 149.70 ea 124.70 efb 110.20 ec 130.10 deb means in a column followed by same small letter and in a row by same capital letter did not differ significantly the highest number of seeds pod-1(220.80) was found from the genotype acc.4311grown at manikgonj which was statistically similar (196.90) with that of the same genotype sown on the same date at joshsore. seeds pod-1of other two genotypes (o-72 and o-3820) were higher at other locations sown on the 15 august. lower number of seeds pod-1(110.20 to149.70) of three genotypes was recorded from the crops of 30 august sowing. seed weight the thousand seed weight of tossa jute was significantly differed due to the interaction effect of genotype and sowing date at four locations. the highest thousand seed weight (2.478 g) was recorded from the seeds of genotype acc.4311sown on 15 august produced at manikgonj followed by the thousand seed weight (2.391 g) of same genotype at joshore (table 4). the genotype o-72 recorded 2.383 g of thousand seed weight from the crops sown on 15 august. the lowest thousand seed weight (1.691 g) was found from the seeds of genotype acc. 4311 sown on 30 august at dinajpur. table 4 revealed that all the three genotypes sown on 30 august produced small sized seeds at all the locations and then thousand seed weight decreased with delayed sowing of crop. table 4. genotype and sowing date effects on seed weight (g) of olitorius jute at four locations treatments locations genotypes sowing dates manikgonj cumilla dinajpur joshore o-72 31 july 2.157 da 1.880 dc 2.103 aa 1.971 cb 15 august 2.383 ba 2.128 cb 1.901cc 2.177 bb 30 august 1.845 fa 1.715eb 1.720 eb 1.832 dea o-3820 31 july 2.056 ea 1.921 db 2.036 ba 1.871 db 15 august 2.295 ca 2.202 bb 1.835 dc 2.250 bab 30 august 1.815 fa 1.732 eb 1.735 eb 1.807 ea acc.4311 31 july 2.260 ca 2.175 bcbc 2.132 ac 2.218 bab 15 august 2.478 aa 2.304 ac 2.035bd 2.391ab 30 august 1.897 fa 1.767 ec 1.712 ec 1.859 dea means in a column followed by same small letter and in a row by same capital letter did not differ significantly by dmrt at 0.05 level. 86 alam et al. seed yield the seed yield of three jute genotypes varied from 460 to 1241 kg ha-1 over the location and sowing dates (table 5). the genotype acc.4311 sown on 15 august produced maximum seed yield at manikgonjwhich was significantly higher than those of sown on 31 july and 30 august at the same location. similar trend of yield was observed in the case of genotypeso-72 and o-3820 at all the locations. the lowest seed yield was recorded from the genotype acc.4311 sown on 30 august at dinajpur which was statistically similar with the seed yield of genotype o-72 and o-3820 grown at the same location and sown on the same date. several authors (hossain and wahab, 1980; talukder and hossain, 1989; bhattacharjee et al., 2000 and alamet al., 2002) also reported that jute yield primarily dependent on the number of pod bearing branches plant-1and then other yield components of crop. higher seed yield of jute sown on 15 august might have been due to its maximum number of pods plant-1and higher number of seeds pod-1.this result also agreed with the findings of alom et al. (2010) who reported that august sowing is better for quality seed production of tossa jute in late season. table 5. effect of different genotypes and sowing dates on the seed yield (kg ha-1) of olitorius jute at four locations treatments locations genotypes sowing dates manikgonj cumilla dinajpur joshore o-72 31 july 1050 da 910 bb 941 abb 960 cb 15 august 1161 aba 1031 ab 851 cdc 1060 bb 30 august 751 ga 551 dc 461 ed 641 fb o-3820 31 july 950 ea 821 cc 911 bcab 865 dbc 15 august 1061 cda 941 bb 821 dc 1041 ba 30 august 660 ha 541 db 530 eb 556 gb acc.4311 31 july 1141 bca 1001 abb 996 ab 1020 bb 15 august 1241 aa 1061 ac 951 abd 1151 ab 30 august 841 fa 571 dc 451 ed 730 eb means in a column followed by same small letter and in a row by same capital letter did not differ significantly by dmrt at 0.05 level. conclusion from the results it may be concluded that sowing of olitoriusjute seed in the first fortnightof augustis better for higher seed yield. among the genotypes, acc.4311 was found superior in yield and othertraits which can be incorporated into the genetic background of high quality genotypes in order to have good quality seeds and to limit seed deterioration which is very important under tropical climates. references alam, m.j., m.m. haque and s.m.m. ali. 2009. seed viability and vigour of five bush bean genotypes in relation to seed development period. ecofriendlyagril. j. 2: 624-631. alam, m.m., a.t.m.m. alam, s. khandker, m.n. gani, s.a. ahmed and a. haque. 2002. fertilizer management of late jute seed production in different agro-ecological zones of bangladesh. pakistan j. biol. sci. 5:410-412. alom, f.m., a.t.m.m. alam, r.k. ghosh, m.i.k. zia and m.m. islam. 2010. planting time and sowing method effects on jute seed yield. seed tech. j.1: 55-62. genotype and sowing date effects on seed yieldof jute 87 bhattacharjee, a.k., b.n. mttra and p.c. mttra. 2000. seed agronomy of jute. ii. production and quality of corchorusolitorius seed as influenced by nutrient management. seed sci. technol. 28: 141-154. bjri. 2006. "nabi pat beezfosolersarbabosthapona" (a bengali booklet). bangladesh jute research institute, sher-ebangla nagar, dhaka-1207. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. second edn. john wiley and sons. inc. new york. pp.304-307. hossain, m.a., a.t.m.m. alam, s. ahmed and a.l. khandakar.1999. effect of planting of jute variety o98797 on seed production. bangladesh j. seed sci. tech. 3: 43-47. hossain, m.a. and m.a. wahab. 1980. effect of intercropping aus and kaon (foxtail millet) with capsularis jute seed crop on yield and return. bangladesh j. jute fib. res. 5:35-40. islam, m.m., i. ahmed, a.t.m.m.alam, s.m. moniruzzaman and m.a.alam. 2007. production of quality olitorius jute seeds by different sowing methods at early season. int. j. sustain. agril. tech. 3(3): 27-30. johansen, c., m. waseque and s. begum. 1985. effect and interaction of photoperiod, water stress on flowering and growth in jute. field crop res.12:397-406. khan, m.a., m.a.samad, m.a. hossain, m.m. islam and g. rabbany. 1997. effect of sowing date and variety on olitorius jute seed production. bangladesh j. jute fib. res. 22(1&2): 19-25. talukder, f.a.h. and m.a. hossain. 1989. response of chorcoruscapsiularis l. to seed yield. bangladesh j. fib res. 14: 31-35. talukder, f.a.h. and m.a. akanda. 1994. physiological maturity of white jute seeds and its influence on viability. bangladesh j. train. dev. 7(1): 53-57. microsoft word 1. baj-273_revised bangladesh agron. j. 2018, 21(1): 1-7 performance of sunflower genotypes in non-saline and saline soils of southern bangladesh m. k. hossain, m. m. islam, a. a. mamun* and s. m. abdullah al mamun agrotechnology discipline, khulna university, khulna-9208, bangladesh *corresponding author, e-mail: mamungpbat@ku.ac.bd (received: 24 april 2017, accepted: 7 june 2017) keywords: non-saline soil, saline soil, sunflower genotype abstract a research work was conducted with three sunflower genotypes to evaluate their performance in saline and non-saline soil after harvesting of t. aman rice. the experiment was laid out in randomized complete block design (rcbd) with four replications. three genotypes significantly influenced almost all the growth and yield parameters in both non-saline and saline field. genotype hysun-33 showed maximum germination percentage in non-saline soil but minimum in saline soil. whereas, kusl-1 performed the best in saline soil but worst in non-saline condition. hysun-33 produced maximum leaf at flowering in both conditions but minimum leaf by bari sunflower-2 in saline soil and by ku-sl-1 in non-saline soil. in both non-saline and saline soils, plant height at flowering, head diameter, total seed head-1 and filled seed head-1 were maximum for the genotype hysun-33 and that of minimum for the genotype bari sunflower-2. genotype ku-sl-1 showed maximum value for 1000seed weight followed by hysun-33 in both saline and non-saline soils. in case of seed yield head-1, hysun-33 performed best in saline soils but worst in non-saline soil. in non-saline soil, ku-sl-1 produced maximum seed yield head-1. biomass at harvest, head diameter and number of filled seed head-1 was well correlated with number of seed head and seed yield head-1. thus genotype hysun-33 may be considered as best for saline and ku-sl-1 for non-saline soil. introduction sunflower (helianthus annuus l.) is an important oilseed crop in the world belongs to the asteraceae family. sunflower seeds are edible. it is a good source of protein, vitamins, calcium, nitrogen and iron. its seed contains 40-45% non-volatile oil and about 55% linoleic acid. a proximate composition of sunflower seed is protein 20.8%, lipid 54.8%, carbohydrates 18.4%, ash 3.9% (gopalan, 1982). in bangladesh, attempts of sunflower cultivation have been initiated and area of production is increasing. now it is being grown in 16 districts of bangladesh and the average production is about 1.2 t ha-1. there is a great scope for growing sunflower after harvest of t. aman rice. sunflower is grown on a wide range of soils and can tolerate a moderate ph and some salinity which is one of the main limiting factors of crop production (chapman and carter, 2000). in south-western khulna region of bangladesh, maximum agricultural lands are usually monocropped with t. aman rice. in late december to mid january, when the rice is harvested, there remains a little chance of growing another crop because soil still remains in high moisture condition that limit tillage operation.when the soil becomes suitable for tillage then the level of soil salinity starts to increase. this situation prevails in all over the coastal region. sunflower has been proved to respond well in minimum tillage system (dibbling method). it is considered as moderately salt and drought tolerant crop, and also a short durated crop (chapman et al., 2 hossain et al. 1993). so, after harvesting of t. aman rice, sunflower seeds can be sown in dibbling method in the month of january thus residual moisture can be exploited. from mid march usually soil salinity start to increase, when vegetative growth of sunflower attains in good condition. in bangladesh, several sunflower varieties have been developed by bari and many have been introduced by some non-government organizations. the suitability test of the varieties for the coastal region is important for improving sunflower productivity. therefore, a research was undertaken to evaluate the performance of three sunflower genotypes in non-saline and saline soils of southern region of bangladesh. materials and methods the experiments were conducted at two locations, situated in the low high ganges river floodplain agro-ecological zone (aez-12), non-saline (fakirhat, bagerhat) and saline (chalna, khulna). two sunflower varieties such as bari sunflower-2 (bari-52) and hysun33 and one sunflower line ku-sl-1 were used in the experiment. just after harvesting of t. aman rice, sunflower seeds were sown by dibbling method maintaining a line distance of 75 cm and plant to plant distance of 45 cm. the unit plot size was 4 m x 5m following randomized complete block design (rcbd). seeds were treated with fungicide vitavex-200 before 24 hours of sowing at the rate of 3 g kg-1 seed and were soaked overnight before sowing. two seeds were dibbled hill-1. after seedling emergence, the vacant hills were filled up by resowing. the manures and fertilizers as recommended by bari was applied and other intercultural operations were maintained. salinity level was measured (by electrical conductivity method) for saline soils at vegetative (at 45 das), flowering and at harvesting stage and was 6.90, 8.15 and 9.25 dsm-1, respectively. data were recorded from five randomly selected plants from each plot. the collected data were analyzed statistically with the help of a computer program mstat-c and the treatment means were compared with duncan’s new multiple range test (dmrt) (gomez and gomez, 1984). results and discussion germination the genotypes of sunflower had significant effect on seedling emergence in non-saline as well as in saline soil at 5, 10, 15 and 20 days after sowing (das) (figure 1). in non-saline soil, hysun-33 showed maximum seedling emergence followed by bari-s2, while ku-sl-1 produced minimum seedling. in non-saline soil, bari sunflower-2 showed quick seedling emergence (21.02% at 5 das) than other two genotypes. ku-sl-1 had slow rate of seedling emergence in both conditions. initially (at 5, 10 and 15 das) it produced minimum seedling (2.92, 38.60 and 66.59 %, respectively) but finally maximum seedling emergence (91.11%), in saline soils, was recorded in this line followed by bari sunflower-2 whereas hysum-33 showed maximum seedling emergence in non-saline condition. this may be due to the slow adjustment of salinity by ku-sl-1 and slow harmful effect of salinity on bari sunflower-2 and hysun-33 in seedling emergence. mubshar et al. (2012) also found significant variations in days to germination and decreased rate of germination with salinity. performance of sunflower genotypes in non-saline 3 das= days after sowing; lsd= least significant difference figure 1. emergence (%) of sunflower seedling in saline and non-saline soil growth parameters genotypic performance of sunflower on plant height at flowering, head diameter at maturity and biomass at harvest varied significantly in both non-saline and saline soils. variation in leaves plant-1 at flowering and stem diameter at maturity was not significant in non-saline soils but significant in saline soils (table 1). in non-saline soils, plant height varied from 96.55 to 134.68 cm and in saline soils it was from 77.03 to 99.43 cm. for both saline and non-saline soils, the tallest plant was found in hysun-33 and the shortest in bari sunflower-2. in saline soil, maximum leaves plant-1 (22.48) at flowering was found in hysun-33 and minimum (13.03) in bari sunflower-2.the highest stem diameter (5.49 cm) was found in bari sunflower-2 and lowest diameter (5.10 cm) in ku-sl-1 in non-saline soils but the robust stem (5.53 cm) was recorded from hysun-33 and thin stem (4.19 cm) from bari sunflower-2 in saline soils. in both non-saline and saline soils, the largest head (19.03 and 17.06 cm, respectively) was found in hysun-33 and the smallest head (14.56 and 11.41 cm, respectively) in bari sunflower-2. in non-saline soil, maximum biomass accumulation (174.42g) was recorded for ku-sl-1 and that of minimum (38.26g) in bari sunflower-2 but in saline soil, highest biomass accumulation (84.12g) was found in hysun-33 followed by ku-sl-1 and that of lowest (68.35g) in bari sunflower-2. each and every genotype showed maximum value for most of the tested characters except leaves plant-1 in non-saline soils than in saline soils. this may be due to the adverse effect of salinity on growth and development of sunflower plants. sarwar et al. (2013) was found 0 10 20 30 40 50 60 70 80 90 100 nonsaline saline nonsaline saline nonsaline saline nonsaline saline 5 das 10 das 15 das 20 das ku-sl-1 bari-s2 hysun-33lsd=4.47 lsd=3.08 lsd=19.58 lsd=10.57 lsd=14.07 lsd=12.27 lsd=10.37 lsd= 9.82 se ed lin g em er ge nc e (% ) 4 hossain et al. significant differences for plant height among sunflower genotypes. islam et al. (2008) reported that the number of leaves of sunflower genotypes decreases significantly with salinity. hanif et al. (1996) also observed significant differences for stem diameter among sunflower varieties. escalante et al. (2010) calculated that total biomass of sunflower decreased with increasing salinity. yield parameters total seed, filled seed, weight of filled seed head-1, 1000seed weight and harvest index (%) varied significantly with sunflower genotypes in both non-saline and saline soils (table 2). in both non-saline and saline conditions, total seeds head-1 (1246.50 and 1139.50, respectively) as well as filled (1217.91 and 1024.09, respectively) were highest in hysun-33 and that of minimum (889.50 and 558.51, respectively; and 824.66 and 498.313, respectively) were produced in bari sunflower-2. this may be due to comparatively large head size and small seed size of hysun-33. in non-saline soils, the highest weight of filled seed head-1 (84.72 g) was found in ku-sl-1 and that of lowest (52.50 g) in bari sunflower-2. but the highest weight of filled seed (65.00 g) was found in hysun-33 and lowest (42.30 g) in bari sunflower-2 in saline soils. genotypes ku-sl-1 had greater 1000seed weight (89.40 and 79.34, respectively) in both non-saline and saline soils than the other two genotypes. in non-saline soil, the maximum harvest index (60.85%) was calculated for the genotypes bari sunflower-2 followed by the genotype hysun-33 (40.15%) whereas in saline soil, genotype hysun-33 showed maximum (43.65%) harvest index followed by ku-sl-1 (40.28%). performance of sunflower genotypes in non-saline 5 table 1. growth parameters of sunflower genotypes in saline and non-saline soils genotype plant height at flowering (cm) leaf number at flowering stem diameter at maturity (cm) head diameter at maturity (cm) biomass plant-1 at harvest (g) non-saline saline non-saline saline non-saline saline non-saline saline non-saline saline ku -sl1 110.48 b 88.20 b 15.45 16.48 b 5.10 4.73 b 16.03 ab 14.52 b 174.42 a 73.47 ab bari -s2 96.55 b 77.03 c 16.45 13.03 b 5.49 4.19 c 14.56 b 11.41c 38.26 c 68.35 b hysun -33 134.68 a 99.43 a 17.95 22.48 a 5.38 5.53 a 19.03 a 17.06 a 78.75 b 84.12 a cv (%) 7.77 5.30 13.04 14.48 15.59 4.66 11.63 7.36 19.45 9.41 lsd (5%) 15.31 8.09 ns 4.34 ns 0.39 3.33 1.83 32.69 12.26 ns =not significant; das = days after sowing; cv= coefficient of variation; lsd= least significant difference; values bearing same letter(s) did not differ significantly but with dissimilar letter(s) differ significantly. table 2. effect of saline and non-saline conditions on yield contributing traits of sunflower genotypes genotype total seeds head-1 filled seeds head-1 weight of filled seeds head-1 (g) 1000 grain weight (g) harvest index (%) non-saline saline non-saline saline non-saline saline non-saline saline non-saline saline ku -sl-1 961.58 b 841.71b 1115.41 a 733.92b 84.72 a 49.64 b 89.40 a 79.34 a 32.68 b 40.28 ab bari -s2 889.50 b 558.51c 824.66 b 498.313 c 52.50 b 42.30 c 56.09 b 62.64 b 60.85 a 38.30 b hysun -33 1246.50 a 1139.50 a 1217.91a 1024.09 a 52.88 b 65.00 a 56.03 b 54.65 b 40.15 b 43.65 a cv (%) 15.82 13.92 10.71 16.02 11.47 5.21 13.45 8.77 22.45 16.26 lsd (5%) 282.6 203.9 195.1 208.4 12.58 4.71 15.64 9.95 17.31 4.41 ns =not significant; das= days after sowing; cv= coefficient of variation; lsd= least significant difference; values bearing same letter(s) did not differ significantly but with dissimilar letter(s) differ significantly. 6 hossain et al. each genotype produced maximum value for the tested traits in non-saline soils than that of in saline soils.this may be due to harmful effect of salinity. these findings are in agreement with sarwar et al. (2013) who found variable performance of sunflower genotypes with variable climatic conditions. correlation character association studies indicated that plant height had positive correlation with head diameter. similar results were reported by chikkadeviah et al. (2002). for both saline and nonsaline soils, biomass at harvest, total seed head-1 and number of filled seed head-1 had positive correlation with head diameter and weight of filled seed head-1. among these, biomass at harvest and number of filled seed head-1 had relatively greater correlations with weight of filled seed head-1 (table 3).this is in accordance with the reports of lakshmanaiah (1979) and dagustu (2002). table 3. correlation between different characters of sunflower genotypes in saline and nonsaline soils nlf bioh phf sdm hdm nsh nfsh nush bioh nsl -0.16 sl 0.59 phf nsl 0.37 0.09 sl 0.83 0.83 sdm nsl 0.59 -0.09 0.19 sl 0.77 0.82 0.79 hdm nsl 0.55 0.17 0.63 0.34 sl 0.77 0.64 0.86 0.87 nsh nsl 0.45 0.02 0.65 0.72 0.75 sl 0.77 0.74 0.90 0.91 0.80 nfsh nsl 0.32 0.49 0.66 0.09 0.75 0.48 sl 0.75 0.71 0.89 0.89 0.89 0.98 nush nsl 0.64 -0.51 0.57 0.31 0.69 0.57 0.32 sl 0.63 0.44 0.41 0.57 0.45 0.41 0.41 wfsh nsl -0.30 0.86 0.01 -0.11 0.13 0.04 0.21 0.68 sl 0.83 0.71 0.82 0.88 0.84 0.83 0.82 0.68 legends: ns l= nonsaline soil, sl= saline soil, nlf = number of leaf at flowering, bioh = biomass at harvest, phf = plant height at flowering, sdm= stem diameter, hdm = head diameter, nsh = number of seed head-1, nfsh = number of filled seed head-1, nush = number of unfilled seed head-1, wfsh = weight of filled seed head-1. conclusion for both the saline and non-saline soils, biomass at flowering, number of seed head-1, number of filled seed head-1 and number of unfilled seed head-1 had positive correlation with head diameter and weight of filled seed head-1. among these, biomass at harvest and number of filled seed head-1 (0.75) had relatively greater correlations with weight of filled seed head-1. genotype hysun-33 may be the best for saline and ku-sl-1 for non-saline soils. references performance of sunflower genotypes in non-saline 7 chapman and carter. 2000. crop production principle and practices (2nd edn.). surjeet publications, delhi. p.566. chapman, s. c., g. l. hammer and h. meinke. 1993. a sunflower simulation model i. model development. agron. j. 85(3): 725-735. chikkadevaiah, h. l., sujatha and nandini. 2002. correlation and path analysis in sunflower. helia. 25: 109−118. dagustu, n. 2002. correlation and path coefficient analysis of seed yield components in sunflower (helianthus annuus l.). turkish j. of field crops. 7: 15-19. escalante, a., j. a. estradaand and m. t. rodriguez-gonzalez. 2010. sunflower biomass distribution and seed yield in saline soil of mexico highlands. helia. 33(52): 127-134. gomez, k. a. and a. a. gomez. 1984. statistical procedures in agricultural research (2nd edn.). paperback, new york. p. 680. gopalan, h. 1982. nutritive value of indian foods, dilhi, india. p. 11. hanif, m., farhatullah and raziuddin. 1996. corellation studies of grain yield and other characters in sunflower varieties. sarhad j. agric. 12(6): 649-652. islam, m., s. afzal, i. ahmad, a. haq and a. hussain. 2008. salt tolerance among different sunflower genotype. sarhad j. agri. 24(2): 242-250. lakshmanaiah, v. h. 1979. genetic variability and association of morphological characters with seed yield and oil content in sunflower (helianthus annuus l.). mysore j. agri. sci. 14: 259261. mubshar, h., m. farooq, m. shehzad, m. b. khan, a.wahid and g. shabir. 2012. evaluating the performance of elite sunflower hybrids under saline conditions. int. j. agric. biol. 14: 131– 135. sarwar, m. a., m. n. k. rehman, h. m. r. javeed, w. ahmed, m. a. shehzad and h. t. abbas. 2013. comparative performance of various sunflower hybrids for yield and its relative attributes. cercet agron moldova. 4(6): 156 bangladesh agron. j. 2018, 21(2): 67-71 response of mustard to soil test based fertilizer management m. h. hossain1, s. k. bhowal 2*, m. m. h. bhuiyan3, a. k. m. s. haque4, a. s. m. m. r. khan5 1principal scientific officer, onfarm research division, bangladesh agricultural research institute, cumilla, bangladesh 2 & 3scientific officer, onfarm research division, bangladesh agricultural research institute, cumilla, bangladesh 4principal scientific officer, ars, bangladesh agricultural research institute, cumilla, bangladesh 5chief scientific officer, onfarm research division, bangladesh agricultural research institute, gazipur, bangladesh *corresponding author, e-mail: shamal.bau@gmail.com (received: 13 january 2019, accepted: 9 may 2019) keywords: stb fertilizer management, mustard yield, cost and return analysis abstract a field experiment was carried out at sonapur of muradnagar upazilla in cumilla district under the debidwar mlt (multi-location testing) site during the rabi season of 2013-15. the experiment was conducted in the old meghna estuarine floodplain (aez-19) soil. the experiment was laid out in randomized complete block design (rcbd) with 3 replications. the treatments were: t1= soil test based (stb) fertilizer dose (frg 2012), t2= t1+ 15% stb, t3= t1+ 30% stb, t4= 80% stb from inorganic fertilizer + 20% stb from cd/pm, t5= farmers’ practice and t6= control. among the treatments, t4 gave the maximum seed yield (1385.56 kg ha-1) which was at par with t1, t3 and t2 treatments. the lowest seed yield (450.20 kg ha-1) was obtained from t6 (control). introduction mustard is one of the major oilseed crops in bangladesh that occupies 78% of the oilseed area and contributes nearly 62% of the total oilseed production in bangladesh (bbs, 2009). in cumilla region, a vast area is used for mustard cultivation in between t. aman and boro (anonymous, 2014). they also cultivate mustard as a mixed crop with boro rice (haider et al., 2015). bangladesh agricultural research institute (bari) developed several high yielding mustard varieties and these varieties may out yielded the local variety in terms of increased yield per unit area (mondal et al., 2014). among high yielding mustard varieties, bari sarisha-14 is found to produce a higher yield in plain land and char land areas without hampering the next crop (islam et al., 2011). on the other hand, farmers generally do not use organic fertilizer or use a higher dose of chemical fertilizers or indiscriminately use chemical fertilizers for mustard cultivation (bhowal, et al. 2014). they have no knowledge or have little knowledge about soil test based fertilizer application. so, the higher yield gap exists in the farmer’s field. now, it is essential to find out the optimum dose for soil test based of fertilizer recommendation for higher yield and economic return of mustard. materials and methods mailto:shamal.bau@gmail.com 68 hossain et al. the experiment was conducted at sonapur of muradnagar upazilla in cumilla district under the debidwar mlt site during 2014-15. the experimental site was situated in aez-19 (old meghna estuarine floodplain). soil samples were collected from the experimental plots and analyzed. the soil was sandy loam in texture with ph 6.5. the physiochemical properties of the initial soil of the experimental field were presented in table 1. initial nutrients content values were used in calculating soil test based fertilizer dose. the experiment was laid out in randomized complete block (rcb) design with 3 replications. the unit plot size was (4 x 3) m2. row to row distance was 30 cm and seeds of mustard var. bari sarisha-14 were sown on 11 november, 2014 continuously. the treatments were t1 = soil test based (stb) fertilizer dose (frg 2012), t2 = t1+ 15% stb, t3 = t1 + 30% stb, t4 = 80% stb from inorganic fertilizer + 20% stb from cd/pm, t5 = farmers’ practice, t6= control. fertilizers were applied as per treatment. half of the nitrogen and full quantity of cow dung, p, k, s and b were applied at the time of final land preparation. urea, tsp, mop, gypsum and boric acid were used as a source of n, p, k, s and b, respectively. the remaining half of nitrogen was applied as a top dress at the flowering stage (25 days after seeding) and covered with soil followed by irrigation. intercultural operations like weeding, mulching were done as and when necessary. yield components like a number of siliqua plant-1, seeds siliqua-1 and 1000 seed weight were taken from randomly selected 10 plants from each plot. the crop was harvested at 75 days after sowing. seed yields were taken from the whole plot. data on yield and yield components were analyzed statistically by statistix 10 program and the means were adjusted using lsd test at 5% level of significance (statistix 10, 2013). table 1. physio-chemical properties of initial experimental soil at farmer’s field, ghorashal, muradnagar, cumilla location ph k total n (%) p s b meq100 ml-1 µg ml-1 muradnagar, cumilla 6.5 0.046 0.04 6.0 38 0.18 critical level 0.12 7. 0 10 0.20 interpretation slightly acidic very low very low low very high low results and discussion yield and yield attributing characteristics yield components and yield of bari sarisha-14 under different fertilizer management practices are presented in table 2. from the findings, it was found that there is no significant difference among t1, t2, t3 and t4 treatments regarding the plant height. the lowest plant height (80.90 cm) was recorded in t6 treatment. the maximum number of the primary branch (3.6) was found in t4 treatment where 80% stb from inorganic fertilizer + 20% stb from cd was used but it was statistically similar with t1 and t3, respectively. a number of siliqua plant-1 (9.93 – 39.40) differed significantly under different soil test based fertilizer managements. it increased with different soil test based fertilizer management levels. a maximum number of siliqua per plant was recorded from t4 treatment that was followed by t1, t3 and t2 treatments and minimum in t6 treatment. it was observed that higher number of pods per plant (39.40), 1000 seeds weight (2.97 g) and seed yield (1385.33 kg ha-1) was found in t4 treatment that was statistically similar with t2 and t3 treatments (fig. 1 and fig. 2). datta et al. (2011) also reports that the significant variation in 1000-seed weight of bari sarisha-11 under different fertilizer managements may be response of mustard to soil test based fertilizer management 69 attributed to different growth rate, dry matter accumulation and variable rate of translocation of assimilates towards seeds. on the other hand, the lowest seed yield (450.20 kg ha-1) was obtained from t6 (control). the variation in seed yield of mustard was also observed by mandal and sinha (2004) and explained that it may be attributed to the total dry matter production and it’s partitioning to different yield contributing organs. cost and return analysis from cost and return analysis it was revealed that the gross return varies with different soil test based fertilizer management practices (table 3) and the highest gross return (tk. 48,487 ha-1) was recorded in t4 treatment due to increase in yield of mustard where 80% stb from inorganic fertilizer + 20% stb from cd i.e n-p-k-s-b (96-36-56-0-0.72) kg ha-1 + 20% from cow dung were used. cost of production increased mainly with increasing fertilizers levels in different fertilizer management packages. table 2. effect of different fertilizer packages on yield contributing characters of mustard at muradnagar, cumilla (pooled data of 2013-14 and 2014-15) treatments plant height (cm) branch plant-1 (no.) pods plant-1 (no.) weight of seed plant-1 (g) t1 114.93 3.27 36.73 14.13 t2 114.07 2.53 36.33 19.87 t3 107.80 3.53 35.53 19.27 t4 114.13 3.60 39.40 21.89 t5 120.67 2.77 33.47 17.87 t6 80.90 1.63 9.93 8.87 cv (%) 5.35 7.64 8.64 8.62 lsd (o.o5) 10.53 0.40 5.12 2.66 note:t1= soil test based (stb) fertilizer dose (frg 2012) i.e n-p-k-s-b (120-45-70-0-0.9 ) kg ha-1, t2= t1+15% stb i.e n-p-k-s-b (138-51.75-80.5-0-1.04) kg ha -1 , t3= t1+30% stb i.e n-p-k-s-b (156-58.5-91-0-1.17) kg ha-1, t4=80% stb from inorganic fertilizer+20% stb from cd/pm i.e n-p-k-s-b (96-36-56-0-0.72 ) kg ha-1+20% from cow dung, t5= farmers practice i.e n-p-k(170-95-100) kg ha-1, t6= control i.e no fertilizer used. fig. 1. relationship of different packages of stb fertilizers with seed weight and yield of mustard the maximum cost of production was recorded in t3 treatment (tk. 30,500 ha -1) and the lowest in control (tk. 12,000 ha-1). the gross margin and benefit-cost ratio (bcr) also varies towards different soil test based fertilizer management and it followed a trend similar to that of gross return. the highest gross margin (tk. 70 hossain et al. 18,987 ha-1) and bcr (1.64) were obtained from t4 treatment where 80% stb from inorganic fertilizer + 20% stb from cd i.e n-p-k-s-b (96-36-56-0-0.72) kg ha-1 + 20% from cow dung were used. banerjee et al. (2010) also agree with the above findings and stated the impact of different combined doses of fertilizers with plant growth regulators on growth, yield attributes and yield of mustard (brassica campestris cv. b9). table 3. economic analysis of mustard var. bari sarisha-14 at muradnagar, cumilla (pooled) treatments gross return (tk. ha-1) total cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr t1 42294 28499 13795 1.48 t2 48319 29773 18546 1.62 t3 45449 30500 14949 1.49 t4 48487 29500 18987 1.64 t5 43277 29600 13677 1.46 t6 15757 12000 5757 1.31 note:t1= soil test based (stb) fertilizer dose (frg 2012) i.e n-p-k-s-b (120-45-70-0-0.9 ) kg ha-1, t2= t1+15% stb i.e n-p-k-s-b (138-51.75-80.5-0-1.04) kg ha -1 , t3= t1+30% stb i.e n-p-k-s-b (156-58.5-91-0-1.17) kg ha-1, t4=80% stb from inorganic fertilizer+20% stb from cd/pm i.e n-p-k-s-b (96-36-56-0-0.72 ) kg ha-1+20% from cow dung, t5= farmers practice i.e n-p-k(170-95-100) kg ha-1, t6= control i.e no fertilizer used, price of mustard @ 35 tk kg-1 farmers’ opinion farmers’ opined that they did not know the soil test based fertilizer application method and amount of fertilizer required for mustard cultivation. they are happy with the result of the experiment and express their opinion on over dose chemical fertilizers. the experiment may be helpful for other mustard growers in this block or area. fig. 2. pictorial view of the experimental field at muradnagar, cumilla, bangladesh with individual treatment conclusion response of mustard to soil test based fertilizer management 71 based on the experimental result it was clearly revealed that fertilizers application especially soil test based fertilizer application had the effect on plant growth, yield and yield contributing characters of mustard. among the different soil test based fertilizer management packages, 80% stb from inorganic fertilizer + 20% stb from cd i.e n-p-k-s-b (96-36-56-0-0.72) kg ha-1 + 20% from cow dung is the best considering yield and economic benefit in cumilla region. references anonymous, 2014. annual research report. onfarm research division, bangladesh agricultural research institute (bari), gazipur, bangladesh. 276 p. bbs (bangladesh bureau of statistics). 2009. statistical yearbook of bangladesh. statistical division, ministry of planning, government of the people’s republic of bangladesh. banerjee, a., j. k. datta and n. k. mondal. 2010. impact of different combined doses of fertilizers with plant growth regulators on growth, yield attributes and yield of mustard (brassica campestris cv. b9) under old alluvial soil of burdwan, west bengal, india. front. agric. china 4(3): 341-351. bhowal, s. k, m. m.u. chowdhury, m. s. bhuiyan, a. h. m. a. faisal, i. s. m. farhad and s.k. bhowmik. 2014. yield and yield attributes of lentil (lens esculenta) as a mixed crop with mustard (brassica campestris). sci. agri. 8 (2), 2014: 76-79 © psci publications datta, j.k., a. banerjee, m. saha sikdar, s. gupta and n.k. mondal. 2011. impact of combined exposure of chemical, fertilizer, bio-fertilizer and compost on growth, physiology and productivity of brassica campestries in old alluvial soil. j. environ. biol. 30(5): 797-800. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka1215. 274p islam, m.n., m. akhteruzzaman, f. ahmed, m.s.a. khan and s. begum. 2011. performance of mustard, lentil and hybrid maize varieties in charland of kushtia district. j. expt. biosci. 2(1):01-04. mandal, k.g., and a.c. sinha. 2004. nutrient management effects on light interception, photosynthesis, growth, dry matter production and yield of indian mustard (brassica juncea). j. agronomy crop sci. 190: 119-129. mondal, m. r. i., m. k. sultan, s. nour, m. j. u. sarkar, m. s. alam, m. h. h. rahman, (2014 edited), krishi projukti hatboi (handbook on agrotechnology), 6th edition, bari, gazipur 1701, bangladesh statistix 10, 2013. user’s manual, copyright © 1985-2013. analytical software. email to support@statistix.com bangladesh agron. j. 2019, 22 (1): 71-78 fertilizer recommendation for four crop based cropping pattern: potatoborot. aus-t. aman under aez – 11 a. barman1*, s. shome2, m.j. alam3, s. akhter1 and m.a. hossain1 1soil science division, bari, gazipur, bangladesh 2department of agronomy, sau, dhaka, bangladesh 3rars, bari, jashore, bangladesh *corresponding e-mail: alakbarman.sau@gmail.com (received: 19 may 2019, accepted: 30 august 2019) keywords: cropping pattern, fertilizer, rice equivalent yield abstract a field experiment on potato-boro-t. aus-t. aman cropping pattern was conducted in the high ganges floodplain soil of jashore (aez 11) during 2014-2015 and 2015-2016 to find out optimum fertilizer management for intensive cropping pattern, in relation to soil health.there were eight different treatments viz. t1=100% npksznb (stb= soil test based), t2=t1 + 25% n, t3=t1 + 25% np, t4=t1 + 25% nk, t5=t1 + 25% pk, t6=t1 + 25% npk, t7=75% of t1, and t8=native fertility (control) as individual crop management. the experiment was laid out in randomized complete block design with three replications. results revealed that the tuber yield of potato, grain yields of boro, t. aus and t. aman were significantly influenced by the fertilizer treatments. the maximum tuber yield (25.70 and 24.80 t ha-1), grain yields of boro (6.50 and 6.31 t ha-1), t. aus (3.13 and 3.10 t ha-1) and t. aman (3.95 and 3.98 t ha-1) was obtained from the t6 treatment where 25% additional npk was added with 100% stb in both the year. these yields were statistically similar with that produced by all other fertilizer treatments except the native fertility treatment. highest rice equivalent yield (rey) of 12.63 t ha-1 was obtained from t6 treatment whereas lowest rey of 5.93 t ha-1 was obtained from control. introduction feeding the enormous population of bangladesh is a great challenge for the farmers and agricultural scientists. at present the total cultivable land of bangladesh is 8.5 million hectare which is decreasing gradually because cultivable land is used as non-agriculture (bbs, 2012). the present cropping intensity is 190% and that can be increased up to some extent by improving the present cropping pattern, incorporating short duration crops and through management of cultivation practices (orc, 2013). most of the major cropping patterns practiced around the country are comprised of two to three crops a year. recently four crop based cropping pattern has been introduced in many aezs. but intensive land use without appropriate soil management has caused depletion of soil fertility in bangladesh. the present system of fertilizer application is mostly based on the nutrient requirement of individual crops ignoring the carryover effect of the organic or inorganic fertilizers applied to the preceding crop. for maintaining soil quality and attainable crop yields for such intensive cropping pattern, proper fertilizer management is required. considering the above facts, the present study was undertaken to find out judicious fertilizer recommendation for potatoboro-t. aust. aman cropping pattern for aez-11. 72 barman et al. materials and methods the field experiment was conducted at the central farm of rars jashore (aez 11) during 2014-2015 and 2015-2016. the initial soil samples, collected before establishing the experiment from a depth of 0-15 cm were analyzed in the laboratory following standard methods. initial values of some important soil chemical parameters of the experimental soil are presented in table 1. table 1. chemical properties of experimental soil (initial) at rars jashore ph om (%) ca mg k total n % p s b cu fe mn zn meq100 g-1 soil g g-1 7.7 0.92 7.8 3.4 0.18 0.048 15 13 0.14 3 29 5 1.8 critical level 2.0 0.5 0.12 0.12 10 10 0.2 0.2 4 1 0.6 the experiment was laid out in a randomized complete block design with three replications. eight different treatments viz. t1=100% stb, t2 = t1+ 25% n, t3 = t1+ 25% np, t4=t1+ 25% nk, t5=t1+ 25% pk, t6=t1+ 25% npk, t7=75% of t1, t8 = native fertility was selected for different plots randomly as individual crop management. the unit plot size was 2.5m  3.0m. potato (var. diamant) was used as test crop for the first component of the pattern. potato seeds were a spacing of 60 x 25 cm on november 11, 2014 and november 10, 2015. fertilizer n-p-k-s-zn and b were supplied from urea, tsp, mp, gypsum, zinc sulphate and boric acid respectively. all p k s zn b and 1/2 of n were applied at the time of final land preparation. the remaining half of n was applied as top dress at 30–35 days after sowing. two irrigations and other intercultural operations were done as and when required. the potato was harvested on january 29, 2015 and january 30, 2016. data on yield and yield contributing characters of potato were recorded and statistically analyzed. after potato, boro rice var. brri dhan28 was transplanted on february 3, 2015 and february 2, 2016 maintaining 20 x 15 cm spacing. all fertilizers including 1/3rd of n were applied before transplanting. rest of n was applied in two installments at 15 and 45 days after transplanting. boro rice was harvested on 12 may, 2015 and 14 may, 2016. for t. aus rice, var. brri dhan48 was used transplanting was done on 15 may 2015 and 17 may 2016 maintaining 20 x 15 cm plant spacing. all fertilizers including 1/3rd of n were applied before transplanting. rest of n was applied in two installments at 15 and 45 days after transplanting. t. aus rice was harvested on 25 july, 2015 and 26 july, 2016. for t. aman rice, the variety binadhan-7 was transplanted on 29 july 2015 and 30 july 2016 maintaining 20 x 15 cm plant spacing. t. aman rice was harvested on november 5, 2015 and november 7, 2016. predetermined plant parameters data were taken as per experimental design. statistix 10 was used to determine the significant differences between the treatments. rice equivalent yield (rey) using formula given by ahlawal & sharma (1993), where, rice equivalent yield (t ha-1yr-1) = yield of each crop (t ha-1) x economic value of respective crop tk. ha-1 crop market price of rice fertilizer recommendation for four crop 77 results and discussion potato yield and yield contributing characters of potato as influenced by the fertilizer (tables 2a and 2b) for two years. fertilizer treatments significantly influenced plant height, tubers plant-1, tuber wt. plant-1, tuber yield (t ha-1) of potato. the highest plant height (66.40 and 65.87 cm), tubers plant-1 (11.26 and 11.06), tuber weight plant-1 (0.58 kg and 0.56 kg) was recorded from the treatment t6 where 25% extra npk was added with 100% stb fertilizer rate in two consecutive years. the lowest plant height (38.60 and 39.24 cm), tubers plant-1 (6.40 and 6.12) and tuber weight plant-1 (0.24 and 0.23 kg) was obtained from control followed by extra 75% of 100% stb. the highest tuber yield of potato (25.70 t ha-1 and 24.80 t ha-1) was produced from the treatment t6 which out yielded all other treatments. the control treatment produced the lowest tuber yield (10.75 t ha-1and 12.95 t ha-1) of potato. saha et al. (2016) recorded higher tuber yield of potato from 20% more than the stb dose in potato-maizet. aman cropping pattern at aez-3. ali et al. (2009) documented lowest number of tubers plant-1, tuber wt. plant-1 and tuber yield from control treatment in potato-borot. aman cropping pattern and mollah et al. (2011) had lowest yield from control treatment in potato-mungbean-t. aman rice cropping pattern. chowdhury et al. (2017) reported 64.3% higher tuber yield of potato in four crop cropping pattern over three crop based cropping pattern. table 2a. plant height, yield and yield contributing characters of potato as influenced by fertilizer management at jashore during 2014-2015 t1: 100% stb (n157 p16 k35 s7.2 zn0.71 b0.85 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: native fertility (control). table 2b. plant height yield and yield contributing characters of potato as influenced by fertilizer management at jashore during 2015-2016 treatments plant height (cm) tubers plant-1 (no) tuber wt. plant-1 (kg) tuber yield (t ha-1) t1 61.92 de 8.30 bc 0.38 de 16.97 cd t2 62.35 cd 9.10 bc 0.45 bc 20.92 b t3 65.12 ab 9.54 b 0.47 b 21.89 b t4 63.33bc 9.19bc 0.45bc 20.84 b t5 62.54 cd 8.42bc 0.40 cd 17.86 c t6 65.87 a 11.06 a 0.56 a 24.80 a t7 59.83 e 7.14 cd 0.35 e 15.92 d t8 39.24 f 6.12d 0.23 f 12.95 e cv (%) 7.79 9.63 5.98 6.22 t1: 100% stb (n157 p16 k35 s7.2 zn0.71 b0.85 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: native fertility (control). treatments plant height (cm) tubers plant-1 (no) tuber wt. plant-1 (kg) tuber yield (t ha-1) t1 62.13 de 8.00 bc 0.40 de 17.89 cd t2 63.86 cd 9.00 bc 0.48 bc 21.27 b t3 66.06 ab 9.46 b 0.50 b 22.78 b t4 64.20 bc 9.13 bc 0.48 bc 21.72 b t5 63.40 cd 8.66 bc 0.44 cd 18.58 c t6 66.40 a 11.26 a 0.58 a 25.70 a t7 60.93 e 7.86 cd 0.37 e 16.00 d t8 38.60 f 6.40 d 0.24 f 10.75 e cv (%) 6.86 9.75 6.41 5.94 72 barman et al. boro the second component of the cropping pattern was boro rice. plant height, yield and yield components of boro rice have been presented in tables 3a and 3b. most of the studied parameters of boro rice were significantly influenced by fertilizer treatments. in 2015, the maximum plant height (96.21 cm) was obtained from t5 treatment which is statistically at par with t2, t3, t4 and t6. in 2016, the maximum plant (96.02 cm) was recorded from t6 treatment which is statistically at par with t2, t3, t4 and t5. tillers hill -1, panicles hill-1, panicle length and straw yields were significantly higher over control treatment. table 3a. plant height, yield and yield contributing characters of boro rice as influenced by fertilizer management during 2015 treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 87.12c 19.92a 19.23a 19.60a 22.50 6.35a 5.50ab t2 91.01ab 19.81a 19.01a 19.61a 23.31 6.23a 5.61ab t3 92.10ab 20.02a 19.12a 19.91a 22.03 6.24a 6.26 a t4 95.11a 19.91a 19.21a 19.92a 21.50 6.43a 5.82ab t5 96.21a 20.22a 19.32a 19.60a 21.90 6.12a 5.80ab t6 94.24a 20.12a 19.62a 19.81a 23.31 6.15a 6.50 a t7 88.04bc 20.02a 19.22a 19.31a 21.21 5.78a 5.24ab t8 78.18d 15.11b 14.42b 16.50b 20.91 4.34b 4.36 b cv (%) 3.68 2.98 2.86 2.11 4.25 9.94 10.43 t1: 100% stb (n186 p30 k23 s30 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. table 3b. plant height, yield and yield contributing characters of boro rice as influenced by fertilizer management during 2016 t1: 100% stb (n186 p30 k23 s30 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. t. aus t. aus rice was transplanted as the third crop of the pattern. the variety used for t. aus rice was brri dhan48, a short duration variety. most of the yield treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 86.04c 19.85a 19.15a 19.50a 22.41 6.20a 5.40ab t2 89.78ab 19.73a 19.02a 19.51a 23.23 6.13a 5.56ab t3 90.98ab 20.00a 19.06a 19.80a 22.02 6.22a 6.31 a t4 94.02a 19.84a 19.10a 19.83a 21.40 6.40a 5.72ab t5 95.05a 20.18a 19.23a 19.55a 21.80 6.01a 5.70ab t6 96.02a 20.13a 19.52a 19.70a 23.24 6.03a 6.31 a t7 87.08bc 20.02a 19.11a 19.24a 21.13 5.71a 5.15ab t8 77.06d 15.04b 14.55b 16.41b 20.80 4.36b 4.32b cv (%) 5.34 3.48 3.12 2.12 5.18 9.72 9.16 fertilizer recommendation for four crop 77 contributing characters and grain yield was significantly influenced by fertilizer treatments. the maximum plant height (94.55 and 93.53 cm) was recorded from the treatment t5 which was statistically identical to t4, t6, t2 and t3. the lowest plant height (76.54 and 75.53 cm) was obtained from the control. there is no significant variation among the treatments except native fertility treatment in case of number of tillers hill-1, number of panicle hill-1, panicle length and straw yield. the highest grain yield of t. aus rice (3.13 t ha-1 and 6.10 t ha-1) was produced by the treatment t6 where 25% additional npk was added with the 100% stb rates (tables 4a and 4b). the control treatment produced the lowest rice yield. the native fertility treatment produced the lowest grain yield (1.92 t ha-1 and 1.84 t ha-1) of t. aus rice. the maximum grain yield (6.26 t ha-1 in 2015 and 6.31 t ha-1 in 2016) was obtained from t6 which followed by other fertilizer variables but significantly different from control (4.36 t ha-1 and 4.32 t ha-1). this result was in agreement with hasan et al. (2017) who opined that an increase of n, p and k fertilizer doses from stb recommended doses significantly increased yield and yield contributing parameters of rice (chaudhary et al., 2011); yoseftabar, 2012). table 4a. plant height, yield and yield contributing characters of t. aus rice during 2015 treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 81.26c 16.71a 16.21a 16.62a 19.51 4.42a 2.83ab t2 90.58ab 16.72a 16.02a 16.63a 19.33 4.21a 2.82ab t3 90.35ab 17.01a 16.11a 16.92a 19.01 4.01a 2.82ab t4 93.45a 16.72a 16.22a 16.91a 19.52 4.62a 2.83ab t5 94.55a 17.23a 16.31a 16.62a 19.92 4.01a 2.92ab t6 92.98a 17.11a 16.62a 16.81a 19.31 4.02a 3.13 a t7 86.32bc 17.02a 16.21a 16.32a 19.43 3.81a 2.11b t8 76.54d 15.13b 14.42b 14.51b 19.92 2.41b 1.92 b cv (%) 3.56 3.56 4.12 2.27 4.13 9.68 9.45 t1: 100% stb (n190 p15 k2.17 s23 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. table 4b. plant height, yield and yield contributing characters of t. aus rice during 2016 treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 81.22c 15.51a 15.11a 15.63a 19.45 4.33a 2.74ab t2 89.34ab 15.62a 15.12a 15.60a 19.34 4.13a 2.73ab t3 89.30ab 16.11a 15.02a 15.92a 19.25 4.04a 2.72ab t4 92.44a 15.81a 15.14a 15.91a 19.44 4.44a 2.74ab t5 93.53a 16.31a 15.23a 15.62a 19.55 4.03a 2.83ab t6 91.92a 16.23a 15.41a 15.81a 19.34 4.02a 3.10 a t7 85.34bc 16.01a 15.15a 15.32a 19.34 3.74a 2.22b t8 75.53d 14.02b 13.81b 13.51b 19.35 2.43b 1.84b cv (%) 4.15 3.27 3.15 3.14 4.97 9.32 9.23 t1: 100% stb (n190 p15 k2.17 s23 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. 72 barman et al. t. aman the fourth component of the cropping pattern was t. aman rice. the yield contributing characters and grain yield of t. aman rice are presented in tables 5a and 5b. most of the yield contributing characters and straw and grain yield of t. aman rice was significantly influenced by fertilizer treatments. high plant height (97.68 and 97.58 cm) was recorded from the treatment t6 where 25% extra npk was added over the 100% stb fertilizer rate which was statistically identical with t5 followed by t1, t2, t3 and t4. the lowest plant height (71.58 and 71.48 cm) was obtained from the control. the maximum number of tiller hill-1 (17.32 and 16.16) was obtained from t6 treatment which was statistically identical with rest of the treatment except t8 which produced lowest number of tillers hill-1 (9.92 and 9.66) in two years). there is no significant variation among the treatments in case of panicle length and 1000grain weight. the highest grain yield (3.95 t ha-1 and 3.98 t ha-1) was obtained from the treatment t6 where 25% extra npk was applied where control treatment produced the lowest grain yield (2.12 t ha-1 and 2.17 t ha-1). ali et al. (2009) reported the highest grain yield from soil test value for hyg and lowest from control treatment. saha et al. (2016) also documented higher yield from 20% more than the stb dose in potato-maize-t. aman cropping pattern of aez-3. table 5a. plant height, yield and yield contributing characters of t. aman rice in 2015 t1: 100% stb (n159 p30 k7 s24 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. table 5b. plant height, yield and yield contributing characters of t. aman rice in 2016 treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 95.38ab 15.91a 15.22b 18.22 21.02 5.61ab 3.51a t2 95.90ab 17.02a 16.31ab 18.31 21.61 5.12abc 3.53a t3 96.42ab 17.12a 16.52ab 18.12 21.01 5.32abc 3.62a t4 96.59ab 16.91a 16.31ab 18.21 21.82 4.83bc 3.52a t5 97.66a 17.12a 16.42ab 18.42 21.91 5.83ab 3.44a t6 97.68a 17.32a 16.82a 18.21 21.12 5.92a 3.95a t7 93.76b 16.01a 15.41ab 18.31 21.22 4.32bc 3.21a t8 71.58c 9.92b 9.22c 18.02 21.32 3.91c 2.12b cv (%) 3.14 4.86 4.76 4.97 3.76 10.80 3.98 treatments plant height (cm) no. of tiller no. of panicle panicle length (cm) 1000 grain wt.(g) straw yield grain yield hill-1 (t ha-1) t1 95.50ab 15.81a 15.17b 18.40 21.05 5.17ab 3.58a t2 95.53ab 16.82a 16.28ab 18.01 21.54 5.08abc 3.58a t3 96.52ab 16.73a 16.45ab 18.90 21.26 5.08abc 3.65a t4 96.41ab 15.94a 15.58ab 18.60 21.14 4.87bc 3.47a t5 97.56a 16.01a 15.86ab 18.32 21.56 5.78ab 3.55a t6 97.58a 16.16a 16.15a 18.11 21.55 5.87a 3.98a t7 93.63b 15.73a 15.17ab 18.72 21.34 4.58bc 3.28a t8 71.48c 9.66b 9.03c 18.51 21.26 3.87c 2.17b cv (%) 3.78 5.34 4.98 5.92 3.56 9.87 7.58 fertilizer recommendation for four crop 77 t1: 100% stb (n159 p30 k7 s24 kg/ha), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control or native fertility. rice equivalent yield to compare among the treatments, potato yield was converted into rice equivalent yield on the basis of prevailing market price of individual crop. the highest rice equivalent yield was recorded from t6 treatment due to the highest yield of potato, boro rice, t. aus rice and t. aman rice. treatment t8 showed lower rice equivalent yield due to lower yield of all the four crops (table 6). ali et al. (2009) also documented significant difference in rice system yield due to different fertilizer doses. table 6. rice equivalent yield of potato-boro-t. aus-t. aman cropping pattern treatments yield of crops in the pattern (t ha-1) rice equivalent yield (t ha-1) potato boro t. aus t. aman potato t1 17.43 5.45 2.79 3.55 8.72 t2 21.10 5.59 2.78 3.56 10.55 t3 22.34 6.41 2.77 3.64 11.17 t4 21.28 5.77 2.79 3.50 10.64 t5 18.22 5.75 2.88 3.49 9.11 t6 25.25 6.29 3.12 3.97 12.63 t7 15.96 5.20 2.17 3.25 7.98 t8 11.85 4.34 1.88 2.15 5.93 price: 1 kg potato = tk. 10, 1 kg rice = tk. 20 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. conclusion from consecutive two years study of four cropping pattern, it could be concluded that stb + 25% extra npk performed better on the whole pattern basis than all other fertilizer levels and this fertilizer package could be used for potatoboro-t. aus-t. aman cropping pattern under jashore region (aez-11). references ahalwat, i.p.s. and sharma, r.p. 1993. agron mid terminology. 3rd edition, new delhi, indian soc. agron. ali, m.r., d.j. costa, m.a. sayed, m.a.h. khanand and j.a. abedin. 2009. development of fertilizer recommendation for the cropping pattern potatoboro-t. aman in irrigated medium highland condition under aez -9. bangladesh j. agril. res. 34(1): 41-49. bbs (bangladesh bureau of statistics). 2012. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning, dhaka. bangladesh. chaudhary, s.k., j.p. singh and s. jhair. 2011. effect of integrated nitrogen management on yield, quality and nutrient uptake of rice (oryza sativa l.) under different dates of planting. indian j. agron. 56(3): 228-231. chowdhury, a.k., t. zahan, m.m. anowar, m.k. islam, s.h. molla and a.s.m.m.r. khan. 2017. improvement of potatojutet. aman cropping pattern through inclusion of mungbean. bangladesh agron. j. 20(2): 87-95. 72 barman et al. hasan, a.b.m.m., s.m. shamsuzzaman, h.a.k. chowdhury, s.m. rasel, n.h. khan, m.e. rahman, m. mehnaz and a.w. samsuri. 2017. effect of different fertilizer packages on the yield and yield attributes on brri dhan47 in saline areas. bangladesh j. bot. 46(1): 467-472. mollah, m.r.a., n. islam and m.a.r. sarkar. 2011. integrated nutrient management for potato-mungbean-t. aman rice cropping pattern under level barind agro ecological zone. bangladesh j. agril. res. 36(4): 711722. orc. 2013. oilseed research centre annual research report. oilseed research centre. bangladesh agricultural research institute, joydebpur, gazipur. saha, p.k., f. rahman, m. akter, r. islam, a.t.m.s. hossain and m.g. ali. 2016. integrated nutrient management for potato-maize-t. aman rice cropping pattern in bangladesh. rice j. 20 (1): 51-58. yoseftabar, s. 2012. effect of nitrogen and phosphorus fertilizer on growth and yield rice (oryza sativa l.). int. j. agron. plant prod. 3(12): 579-584. microsoft word 5 bangladesh agron. j. 2017, 20(2): 37-52 physiological evaluation of wheat genotypes for physiological evaluation of wheat genotypes for physiological evaluation of wheat genotypes for physiological evaluation of wheat genotypes for tolerance to tolerance to tolerance to tolerance to water deficit stresswater deficit stresswater deficit stresswater deficit stress m. s. ranam. s. ranam. s. ranam. s. rana****, m. a. hasan, m. m. bahadur, m. a. hasan, m. m. bahadur, m. a. hasan, m. m. bahadur, m. a. hasan, m. m. bahadur and m. r. islamand m. r. islamand m. r. islamand m. r. islam department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur *corresponding author, e-mail: sohel0901084@gmail.com (receivedreceivedreceivedreceived: 24 april 2017, accepted: accepted: accepted: accepted: 7 june 2017) keywords:keywords:keywords:keywords: wheat genotypes, water stress, stress tolerance and yield abstractabstractabstractabstract four wheat genotypes (bari gom 25, e 28, baw 1170, baw1140) were grown under well water and water deficit stress condition to evaluate the sensitivity of physiological traits of wheat resulting reduced grain yield under water deficit stress. wheat genotypes showed greater stability of flag leaf chlorophyll, greater ability to retain water in leaf, higher level of proline in flag leaf and kernel, higher level of soluble sugar in flag leaf and greater ability to keep the canopy cooler compared to sensitive genotype under water deficit condition. greater spike dry matter accumulation at peak, longer grain growth duration, better yield components such as spikes m-2 and grains spike-1 under water deficit stress contributed to better tolerance of bari gom 25, e 28 and baw 1170. the order of tolerance based on grain yield was baw 1170 > bari gom 25 > e 28 > baw 1140 and the order of tolerance based on above ground biological yield was baw 1170 > e 28 > bari gom 25 > baw 1140. introductionintroductionintroductionintroduction wheat (triticum aestivum l.), next to rice is the staple food of the people of bangladesh grown over an area of 0.45 million hectares with an annual production about 1.35 million metric tons and the average yield 3.03 t ha-1 (bbs, 2016), comparatively low than the other wheat growing countries. wheat is mainly grown under non-irrigated drought conditions during the winter period (november to april) in bangladesh though the vast storage of soil moisture resulted from monson rain supports the wheat growth favorably at the early stages but the plant suffers from water stress at the reproductive stages when the residual soil moisture depletes (karim et al., 2000). water stress causes a declines in relative water content (rwc), chlorophyll (chl) and carotenoid content, membrane stability and nitrate reductase activity and increases accumulation of abscisic acid (aba), proline (chandrasekar et al., 2000), soluble sugar (kameli and loesel, 1993) and leaf and canopy temperature. water deficit reduces the interception of solar radiation in the canopy due to early senescence as well as rolling up the leaves (muller, 2001). due to raise in world temperature soil losses it´s moisture holding capacity as a result drought effect is accelerated. thus, the best option for yield improvement and yield stability of wheat under soil moisture deficit condition is to screen or develop drought tolerant wheat varieties and to ameliorate the adverse effect of water deficit stress through agronomic strategies. . . . the application of physiological tolerance with agronomic traits has been used to be applicable and their interaction with water stress tolerance indices are considered strong enough to be exploited as a selection way in the breeding of water stress tolerance cultivars (allakhverdiev et al., 2000). therefore, the present study was carried out to expand 38 rana et al. wheat cultivation and to sustain wheat yield under drought prone area by evaluating the sensitivity of physiological traits of wheat result in reduced grain yield under water deficit stress. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the experiment was set up at the research farm of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur, bangladesh during november 2014 to april 2015 located at 25º39′ n latitude and 88º41′ e longitude with an elevation of 37.58 meter above the sea level. the experiment was conducted in a splitplot design with three replications. the unit plot size was 2.5 m × 2.0 m. the treatments were a) main plot: two water regimes; irrigations were applied at crown root initiation (cri), anthesis and grain filling stages and water deficit stress and no irrigation was applied and the crop was protected from rainfall by rainout shelter and b) sub-plot: four wheat genotypes viz. bari gom 25, e 28, baw 1170 and baw 1140. a fertilizer dose of 140-35-75-18-2-0.5 kg ha-1 n, p, k, s, zn and b was applied in the form of urea, triple supper phosphate (tsp), muriate of potash (mop), gypsum and boric acid, respectively. after land preparation, full dose of p, k, s, zn, b and two third of n were incorporated thoroughly into the soil as basal dose. the remaining amount of n was applied at 25 days after seedlings emergence. seeds of four wheat genotypes were sown in rows of 20 cm apart, at the rate of 120 kg ha-1. slight irrigation was given for uniform germination after sowing and other intercultural operations were done as per requirement. physiological traitsphysiological traitsphysiological traitsphysiological traits spike dry matter accumulationspike dry matter accumulationspike dry matter accumulationspike dry matter accumulation at anthesis 80 main shoots were tagged from each plot. four tagged main shoot spikes were harvested at every 4th day beginning from anthesis to quantify spike dry matter accumulation pattern. collection of main shoot spike in all genotypes was continued up to 40 days after anthesis (daa) for both well watered and water deficit stress condition. the harvested spikes were kept in oven at 70 oc for 72 hours. after oven drying, spikes were weighted with an analytical balance (and electronic balance model ek 300 i). estimation of prolineestimation of prolineestimation of prolineestimation of proline proline content of flag leaf and kernel at 16 daa of wheat genotypes grown in two growing conditions were estimated according to bates (1973) from a standard curve and calculated on a fresh weight basis as follows: µmoles proline / g of fresh plant material = {(µg proline / ml × ml toluene) / 115.5 µg / µmoles} / (g sample/5) estimation of soluble sugarestimation of soluble sugarestimation of soluble sugarestimation of soluble sugar the soluble sugar content of flag leaf collected at 16 daa of wheat genotypes were determined as yoshida et al. (1976) using standard curve. estimation of chlorophyllestimation of chlorophyllestimation of chlorophyllestimation of chlorophyll total chl content of the flag leaf at 8 and 24 days after anthesis was estimated according to witham et al. (1986) using following formula total chl (mg g-1 fw) = [20.2 (d645) + 8.02 (d663)] × [v/ (1000 × w)] 39 physiological evaluation of wheat genotypes for tolerance (where, v = volume of 80% aqueous acetone (ml), w = weight of fresh leaf (g), d645 = absorbance at 645nm wavelength and d663 = absorbance at 663nm wavelength) leaf relative water content (lrwc)leaf relative water content (lrwc)leaf relative water content (lrwc)leaf relative water content (lrwc) relative flag leaf water content was determined at 16 daa from the equation of schonfeld et al. (1988). rlwc (%) = {(fresh weight – dry weight) / (turgid weight dry weight)} × 100 canopy temperature depression (ctd)canopy temperature depression (ctd)canopy temperature depression (ctd)canopy temperature depression (ctd) the hand held infra-red thermometer (model: crop track item no. 2955l-spectrum tecnologies, inc.) was used to measure the ctd at 8 and 24 daa during noon period under bright sunlight and less wind conditions. agronomical traitsagronomical traitsagronomical traitsagronomical traits plant height, spike length (excluding awn), number of grains spike-1, number of spikes m-2, grain yield m-2, straw yield m-2, thousand grain weights, grain yield and above ground biological yield of wheat genotypes were taken properly. grain and above ground biological yield were adjusted to 12% moisture content. stress susceptibility index (ssi)stress susceptibility index (ssi)stress susceptibility index (ssi)stress susceptibility index (ssi) higher ssi indicates greater susceptibility. ssi was calculated for grain yield as described by fisher and maurer (1978). ssi = (1y/yp ) / (1x/xp ) (where, y = grain yield of genotype in a stress environment, yp = grain yield of genotype in a stress-free environment, x = mean y of all genotypes and xp = mean yp of all genotypes soil moisture content soil moisture content soil moisture content soil moisture content the soil samples were collected from desired depths (15 cm) from several places and were taken in air tight containers. the samples were weighed and then they were dried in an oven at 105oc for about 24 hours or till constant weight. the samples were then taken out from oven and weighed again and the loss in weight (wt.) is the amount of water soil. soil moisture content (%) = {(wt. of moist sample-wt. of oven dry sample) / wt. of oven dry sample} × 100 statistical analysisstatistical analysisstatistical analysisstatistical analysis the data were analyzed by partitioning the total variance with the help of computer by using mstat program. the treatment means were compared using duncun’s multiple range test (dmrt) at p ≤ 5% level of significance. correlation analysis was also done. resultresultresultresultssss and discussionand discussionand discussionand discussion soil moisture contentsoil moisture contentsoil moisture contentsoil moisture content soil moisture content at 0-15 cm depth of well watered and water stressed plots at different days after sowing is presented in figure 1 which shows that well watered plot maintained higher soil moisture (7.40, 9.27 and 8.89%) than that of water stressed plot (4.36, 3.87 and 40 rana et al. 3.30%) at 90, 100 and 110 days after sowing, respectively. besides, soil moisture of water stressed plot was reduced gradually with the advancement of time after sowing. fig. 1. soil moisture content (0-15 cm depth) at different days after sowing as influenced by water regimes. phenological parametersphenological parametersphenological parametersphenological parameters wheat genotypes and water regimes interacted significantly to influence the number of days required to attain anthesis and physiological maturity (table 1). under water stress condition, all the wheat genotypes required shorter time (68-76 days) to attain anthesis compared to well water condition (71-79 days). baw 1170 required maximum days (79 days) under well water condition but anthesis occurred 3 days earlier in this genotype under water stress condition. the genotype e 28 required minimum days (71 days) under well water condition but anthesis occurred 3 days earlier in this genotype under water stress condition. in bari gom 25 and baw 1140 anthesis was 1 and 2 days earlier, respectively under water stress condition compared to well water condition. under water stress condition, all the wheat genotypes required shorter time (102 -109 days) to attain physiological maturity compared to well water condition (105-110 days). the genotype baw 1170 and baw 1140 required maximum days (110 days) under well water condition whereas baw 1170 attained at physiological maturity 1 days earlier and baw 1140 attained at physiological mature stage and 6 days earlier under water stress condition. bari gom 25 and e 28 required minimum days (105 days) to maturity under well water condition whereas bari gom 25 attained at physiological maturity 1 day earlier and e 28 attained at physiological mature stage 3 days earlier under water stress condition. the time required for the phonological development of crops is one of the most important factors for yield adaptation in any environment (motzo and giunta, 2007). in principle, the length of growing period and phenological development of crops can affect the yield either by consuming more resources or by decreasing the environmental tensions or by reducing the length of the periods (attarbashi et al. 2002). in the present study, water deficit stress accelerated anthesis and physiological maturity stage. similar results were also reported by various researchers that water deficit stress reduced the number of days to anthesis (kiliç and yagbasanlar, 2010, sial et al. 2009, khakwani et al., 2012) and days to maturity (kiliç and yagbasanlar, 2010). 0 2 4 6 8 10 12 90 100 110 s o il m o is tu re ( % ) s o il m o is tu re ( % ) s o il m o is tu re ( % ) s o il m o is tu re ( % ) days after sowingdays after sowingdays after sowingdays after sowing well water water stress 41 physiological evaluation of wheat genotypes for tolerance table 1. effect of water regimes on days required to attain anthesis and physiological maturity of different wheat genotypes wheat genotypes water regimes days to anthesis days to physiological maturity number of days early in days over control number of days early in days over control bari gom 25 well watered 74 c 105 b water stress 73 d 1 104 b 1 e 28 well watered 71 e 105 b water stress 68 f 3 102 c 3 baw 1170 well watered 79 a 110 a water stress 76 b 3 109 a 1 baw 1140 well watered 72 d 110 a water stress 70 e 2 104 b 6 level of significance * ** cv (%) 0.48 1.04 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% physiological traitsphysiological traitsphysiological traitsphysiological traits flag leaf chlorophyll contentflag leaf chlorophyll contentflag leaf chlorophyll contentflag leaf chlorophyll content flag leaf chl content at 8 days after anthesis (daa) was significantly influenced by the interaction effect of wheat genotypes and water regimes (table 2). under water stress condition, flag leaf chl was increased by 8.12% in bari gom 25, 7.65% in baw 1170 and 5.37% in baw 1140 whereas it was same both at well water and water stress condition in e 28. flag leaf chl content at 24 days after anthesis (daa) was also influenced significantly by the combined effect of wheat genotypes and water regimes (table 2). due to water stress condition, all the wheat genotypes showed lower flag leaf chl content (0.88-1.39 mg chl g-1fw) compared to well water condition (1.24-1.44 mg chl g-1fw). . . . but the degree of reduction was not same for all wheat genotypes. under water stress condition, flag leaf chl was reduced by 13.88% in bari gom 25, 22.65% in e 28, 3.47% in baw 1170 and 29.03 % in baw 1140. chlorophyll content has been known as an index for evaluation of source, therefore decrease in leaf chl content can be considered as a nonstomatal limiting factor in the drought stress conditions (herzog, 1986). in the present study, flag leaf chl content at 8 days after anthesis remained same or increased under water stress condition, it might be due to the support of the vast storage of soil moisture resulted from monsoon (karim et al., 2000). deora et al. (2001) also reported that chl content in wheat increased in stressed leaves as compared to normal leaves. flag leaf chl content at 24 days after anthesis was reduced due to water stress, as the plant suffers from severe water stress at this stage when the residual soil moisture depletes. the sensitive genotype baw 1140 was found to affect more than the tolerant genotypes (bari gom 25, e 28 and baw 1170) in chl degradation. farshadfar et al. (2014) working with what genotypes also reported that water stress reduced chl content and the reduction was more pronounced in drought susceptible genotypes. 42 rana et al. table 2. effect of water regimes on different physiological traits of wheat wheat genotypes water levels flag leaf chlorophyll content canopy temperature depression at 8 daa at 24 daa at 8 daa at 24 daa mg g-1 fw % change over control mg g-1 fw % change over control oc % change over control oc % change over control bari gom 25 well watered 1.60 c 1.44 a 8.05 4.93 b water stress 1.73 bc + 8.12 1.24 a -13.88 7.50 -6.83 3.44 d -30.22 e 28 well watered 1.84 b 1.28 a 8.46 4.74 b water stress 1.84 b 0.0 0.99 b -22.65 7.60 -10.16 3.18 d -32.91 baw 1170 well watered 1.96 ab 1.44 a 8.86 4.16 c water stress 2.11 a + 7.65 1.39 a -3.47 7.48 -15.57 3.50 d -15.86 baw 1140 well watered 1.86 b 1.24 a 7.62 5.62 a water stress 1.96 ab +5.37 0.88 b -29.03 7.49 -1.71 3.60 cd -35.94 level of significance ** ** ns ** cv (%) 6.69 8.15 5.17 4.45 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% canopy temperature depression (ctd)canopy temperature depression (ctd)canopy temperature depression (ctd)canopy temperature depression (ctd) canopy temperature depression at 8 days after anthesis was not influenced significantly by the interaction effect of wheat genotypes and water regimes but at 24 days after anthesis it was influenced significantly by the interaction effect of wheat genotypes and water regimes (table 2). at 24 days after anthesis, all the wheat genotypes maintained higher ctd (4.165.62°c) under well water condition compared to that (3.18-3.60°c) under water stress condition. ctd was reduced by 30.22% in bari gom 25, 32.91% in e 28, 15.86% in baw 1170 and 35.94% in baw 1140. the results indicated that the tolerant genotypes maintained comparatively a cooler canopy under water deficit stress compared to the sensitive genotype. buttar et al. (2005), and lopes and reynolds (2010) also reported higher canopy temperature in stressed wheat compared to nonstressed wheat. relatively lower canopy temperature in drought stressed crop plants indicates a relatively better capacity for taking up soil moisture and for maintaining a relatively better plant water status by various plant adaptive traits (blum et al., 1989). relative water content of flag leafrelative water content of flag leafrelative water content of flag leafrelative water content of flag leaf relative leaf water content of flag leaf at 16 days after anthesis was significantly influenced by the interaction effect of wheat genotypes and water levels (table 3). at well watered condition, the maximum flag leaf water content was found in baw 1140 (83.84%) which was followed 43 physiological evaluation of wheat genotypes for tolerance by baw 1170 (80.96%) and bari gom 25(80.72%) while e 28 showed the lowest relative leaf water content (80.42%). under water stress condition, all the wheat genotypes showed lower relative leaf water content compared to well water condition except bari gom 25 in which the relative leaf water content was even increased by 2.15%. among the other three genotypes baw 1140 affected more (3.57%) than e 28 (1.24%) and baw 1170 (3.24%) in reducing leaf water content. reduction in the relative water content due to drought stress has been noted in wide variety of plants as reported by nayyar and gupta (2006), farshadfar et al. (2012), hasheminasab et al. (2012) and farshadfar et al. (2014) also reported relative water content as a useful character for selecting drought tolerant wheat genotypes. flag leaf and kernel proline contentflag leaf and kernel proline contentflag leaf and kernel proline contentflag leaf and kernel proline content wheat genotypes and water regimes interacted significantly to influence flag leaf and kernel proline content at 16 days after anthesis (table 3). under well condition, bari gom 25 contained the highest amount of proline in flag leaf (11.98 µmole g-1 fw) which was followed by e 28 (10.28 µmole g-1 fw) and baw 1170 (9.95 µmole g-1 fw) while baw 1140 contained the lowest amount of proline in flag leaf (9.76 µmole g-1 fw).under water stress condition, flag leaf proline was increased by 1 to 5.35% in three tolerant genotypes (bari gom 25, e 28 and baw 1170) whereas the flag leaf proline was reduced by 5.84% in sensitive genotype (baw 1140) compared to well water condition. under well condition, baw 1140 and baw 1170 contained the highest amount of proline in kernel leaf (21.38 µmole g-1 fw) which was followed by bari gom 25 (20.73 µmole g-1 fw) whereas e 28 contained the lowest amount of proline in kernel (17.21 µmole g-1 fw) at 16 days after anthesis. under water stress condition, kernel proline was increased by 1.39% in bari gom 25 and 1.10% in e 28. baw 1170 and baw 1140 failed to accumulate enough quantity of proline in kernel to tolerate water deficit stress. the kernel proline was reduced by 13.98% in baw 1170 and 26.65% in sensitive genotype (baw 1140) compared to well water condition. plants accumulate proline in large quantities in response to environmental stresses. accumulation of proline under stress in many plant species has been correlated with stress tolerance, and its concentration has been known to be usually higher in stress tolerant than in stress sensitive plants. high levels of proline enable a plant to maintain low water potentials. aggarwal et al., (2011) reported that proline provides tolerance against different abiotic stresses by increasing their endogenous level and their intermediate enzymes in plants and osmotically stressful conditions (bayoumi et al., 2008). flag leaf soluble sugar contentflag leaf soluble sugar contentflag leaf soluble sugar contentflag leaf soluble sugar content soluble sugar content in flag leaf at 16 days after anthesis was influenced significantly by the combined effect of wheat genotypes and water regimes (table 3). under well condition, e 28 contained the highest amount of soluble sugar in flag leaf (61.02 mg g-1 dw) which was followed by baw 1170 (54.04 mg g-1 dw) and baw 1140 (51.13 mg g-1 dw) whereas bari gom 25 contained the lowest amount of soluble sugar in flag leaf (48.40 mg g-1 dw). under water stress condition, flag leaf soluble sugar was increased by 2.96 to 25.42% in three tolerant genotypes (bari gom 25, e 28 and baw 1170) whereas the flag leaf soluble sugar was reduced by 9.63% in sensitive genotype (baw 1140) compared to well water condition. 44 rana et al. sugars produced during photosynthesis play a significant role in plant growth and development under abiotic stresses by regulating carbohydrate metabolism. siddique et al. (2000) reported that adaptation to water stress has been attributed to the stress induced increase in sugar levels. table 3. effect of water regimes on different physiological traits of wheat wheat genotypes water levels relative leaf water content at 16 daa flag leaf proline content at 16 daa kernel proline content at 16 daa flag leaf soluble sugar at 16 daa % % change over control µmol g-1 fw % change over control µmol g-1 fw % change over control mg g-1 dw % change over control bari gom 25 well watered 80.72 b 11.98 b 20.73 b 48.40 cd water \stress 82.87 a +2.15 12.62 a +5.34 21.02 b +1.39 60.70 b +25.42 e 28 well watered 80.42 b 10.28 d 17.21 c 61.02 b water stress 79.42 c -1.24 10.83 c +5.35 17.40 c +1.10 69.24 a +13.45 baw 1170 well watered 80.96 b 9.95 d 21.38 a 54.04 bd water stress 78.33 c -3.24 10.05 d +1.00 18.39 c -2.99 55.64 bc +2.96 baw 1140 well watered 83.84 a 9.76 d 21.38 a 51.13 cd water stress 80.84 b -3.57 9.19 e -0.57 15.70 d -5.68 46.40 d 9.63 level of significance ** * ** * cv (%) 1.03 2.87 3.37 7.53 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% spike dry matter spike dry matter spike dry matter spike dry matter accumulationaccumulationaccumulationaccumulation both under well water and water deficit stress condition, a typical sigmoid pattern of dry matter accumulation in spikes were found in all wheat genotypes (figure 2). under well water condition, the spike dry weight was observed to be increased up to 2.64 g at 36 daa in bari gom 25, 2.47 g at 40 daa in e 28, 2.45 g at 40 daa in baw 1170 and 2.68 g at 40 daa in baw 1140 and decline thereafter slowly. under water deficit stress condition, maximum dry matter accumulation in spike was reduced in all wheat genotypes except in e 28 and days required to attain maximum dry weight were reduced in all genotypes except baw 1170.the reduction in maximum spike dry weight were lower in tolerant wheat genotypes (7.58% in bari gom 25, 0.0% in e 28 and 10.61% in baw1170) compared to that in sensitive genotype (19.03% in baw 1140). number of days required to attain maximum dry weight were reduced by o to 4 days in tolerant genotypes (bari gom 25, e 28 and baw1170) but it was 8 days in sensitive wheat genotype (baw 1140). after attaining the highest level in spike dry matter, the reduction could be due to respiratory loss of spike. thus it indicated the importance of harvesting the crop and quickly drying the wheat grains when it attain at 45 physiological evaluation of wheat genotypes for tolerance physiological maturity. similar pattern of spike dry matter accumulation in wheat was also found by hasan et al. (2007) under heat stress condition. fig. 2. spike dry matter accumulation in different wheat genotypes at different days after anthesis as influenced by water regimes. agronomic traitsagronomic traitsagronomic traitsagronomic traits plant height plant height plant height plant height height of plant was not significantly influenced by the interaction effect of water regimes and wheat genotypes but all the wheat genotypes became shorter under water stress condition (91.34 cm to 95.74 cm) compared to that (94.18 cm to 99.67 cm) under well water condition (table 4). in water deficit stress, plant suffers from physical drought and consequently the reduction in plant height was observed. baque (2003) reported that water stress significantly reduced plant height. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) days after anthesisdays after anthesisdays after anthesisdays after anthesis bari gom 25bari gom 25bari gom 25bari gom 25 well water water sress 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) days after anthesisdays after anthesisdays after anthesisdays after anthesis e 28e 28e 28e 28 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) days after anthesisdays after anthesisdays after anthesisdays after anthesis baw 1170baw 1170baw 1170baw 1170 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 4 8 12 16 20 24 28 32 36 40 s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) s p ik e d ry w e ig h t (g ) days after anthesisdays after anthesisdays after anthesisdays after anthesis baw 1140baw 1140baw 1140baw 1140 46 rana et al. spike lengthspike lengthspike lengthspike length the interaction effect of water regimes and wheat genotypes on spike length was found significant (table 4). at well water condition bari gom 25 produced the maximum length of spike (12.96 cm) which was followed by baw 1170 (11.13 cm) and e 28 (11.01 cm) whereas baw 1140 produced the shortest spike (9.83 cm). due to water deficit stress spike length was reduced in all wheat genotypes. but the magnitude of reduction was not same for all wheat genotypes. the reduction was 16.51% in bari gom 25, 2.70% in e 28 and 5.49% in baw1170 and 6.84% in baw 1140. baque (2003) reported that ear length significantly reduced due to water deficit stress. table 4. effect of water deficit stress on plant height and spike length of different wheat genotypes at harvest wheat genotypes water regimes plant height spike length cm % change over control cm % change over control bari gom 25 well watered 98.17 12.96 a water stress 91.79 -6.49 10.82 b -16.51 e 28 well watered 94.18 11.01 b water stress 91.34 -3.01 10.72 b 2.70 baw 1170 well watered 99.67 11.13 b water stress 98.55 -1.12 10.55 bc 5.49 baw 1140 well watered 96.96 9.83 cd water stress 95.74 -1.25 9.20 d 6.84 level of significance ns ** cv (%) 3.35 3.92 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% number of spikes mnumber of spikes mnumber of spikes mnumber of spikes m----2222 the combined effect of water regimes and wheat genotypes on number of spikes per m² was significant (table 5). under well water condition, the maximum number of spikes per m² was observed in baw 1140 (345) which was followed by e 28 (312) and baw 1170 (287) whereas the lowest number of spikes per m² in bari gom 25 (263). due to the effect of water deficit stress number of spikes per m² was affected vigorously in all wheat genotypes. under water deficit stress condition more reduction in number of spikes per m² was observed in sensitive genotype (17.01% in baw 1140) compared to three tolerant genotypes (15.99% in bari gom 25, 11.95% in e 28 and 6.96% in baw 1170). passioura (2007) also found 37% reduction in spike m-2 when moisture stress was imposed during spike emergence and anthesis stage number of grains spikenumber of grains spikenumber of grains spikenumber of grains spike----1111 number of grains spike-1 was significantly influenced by the combined effect of water regimes and wheat genotypes (table 5). under well water condition, the maximum number of grains spike-1 was found in e 28 (46.67) which was followed by bari gom 25 (44.33) and baw 1140 (43.33) whereas the lowest number in baw 1170 (38.67). due to the effect of water deficit stress number of grains spike-1 was reduced in all wheat genotypes. under water deficit 47 physiological evaluation of wheat genotypes for tolerance stress condition more reduction in number of grains spike-1 was observed in sensitive genotype (13.84% in baw 1140) compared to three tolerant genotypes (6.76% in bari gom 25, 1.41% in e 28 and 2.65% in baw 1170). similar response of different wheat genotypes to different moisture levels was found by shahram et al. (2003). table 5. effect of water deficit stress on yield attributes of different wheat genotypes wheat genotypes water regimes spikes m-2 grains spike-1 1000grain weight number % change over control number % change over control g % change over control bari gom 25 well watered 263 d 44.33 ab 50.36 water stress 221 e -15.99 41.33 c -6.76 52.14 +3.53 e 28 well watered 312 b 46.67 a 38.46 water stress 275 cd -11.95 46.00 a -1.41 40.07 +4.18 baw 1170 well watered 287 c 38.67 d 41.91 water stress 267 cd -6.96 37.67 d -2.65 44.34 +5.79 baw 1140 well watered 345 a 43.33 bc 38.98 water stress 268 cd -17.01 37.33 d -13.84 41.95 +7.61 level of significance ** ** ns cv (%) 3.84 3.16 4.91 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% thousand grain weightthousand grain weightthousand grain weightthousand grain weight the interaction effect of water regimes and wheat genotypes on 1000-grain weight was not significant (table 5). in general, all wheat genotypes provided greater grain size under water stress condition (40.07 to 52.14 g 1000-grain-1) compared to well water condition (38.46 to 50.36 g 1000-grain-1). due to water deficit stress condition 1000-grain weight was increased in all genotypesmay be due to the reduction in grain number per spike which favors the larger grain size. grain yield grain yield grain yield grain yield the combined effect of water regimes and wheat genotypes on grain yield was found significant (table 6). under well water condition, the maximum grain yield was recorded in baw 1140 (4.22 t ha-1) which was followed by e 28 (3.89 t ha-1) and bari gom 25 (3.63 t ha-1) whereas the lowest in baw 1170 (3.17 t ha-1). under water deficit stress condition more reduction in grain yield was observed in sensitive genotype (29.49%% in baw 1140) compared to three tolerant genotypes (16.25% in bari gom 25, 16.45% in e 28 and 15.77% in baw 1170). reduced number of spike per m² and grains per spike were the major responsible factors for reducing the grain yield under water deficit stress condition. 48 rana et al. above ground biological yieldabove ground biological yieldabove ground biological yieldabove ground biological yield above ground biological yield was influenced significantly by the combined effect of water regimes and wheat genotypes (table 6). under well water condition, the highest above ground biological yield was found in baw 1140 (9.33 t ha-1) which was followed by bari gom 25 (8.59 t ha-1) and baw 1170 (8.27t ha-1) whereas the lowest in e 28 (8.18 t ha-1). due to water deficit stress above ground biological yield was reduced in all wheat genotypes. under water deficit stress condition more reduction in above ground biological yield was observed in sensitive genotype (31.83% in baw 1140) compared to three tolerant genotypes (29.69% in bari gom 25, 24.33% in e 28 and 23.70% in baw 1170).the results are also in line with the findings of wang et al. (2004). table 6. effect of water deficit stress on grain and straw yield of different wheat genotypes wheat genotypes water regimes grain yield biological yield t ha-1 % change over control t ha-1 % change over control bari gom 25 well watered 3.63 b 8.59 b water stress 3.04 c -16.25 6.04 c -29.69 e 28 well watered 3.89 b 8.18 b water stress 3.25 c -16.45 6.19 c -24.33 baw 1170 well watered 3.17 c 8.27 b water stress 2.67 d -15.77 6.31 c -23.70 baw 1140 well watered 4.22 a 9.33 a water stress 3.06 c -27.49 6.36 c -31.83 level of significance ** * cv (%) 5.54 3.64 in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5% correlation analysis between relative performances of various parameterscorrelation analysis between relative performances of various parameterscorrelation analysis between relative performances of various parameterscorrelation analysis between relative performances of various parameters correlation analysis between relative performances of various parameters studied in this investigation is presented in table 7. relative performance of grain yield maintained a significant positive correlation with the relative performance of flag leaf chl content at 24 daa (0.766**), relative flag leaf water content at 16 daa (0.584**), flag leaf proline content at 16 daa (0.904**), kernel proline content at 16 daa (0.813**), flag leaf soluble sugar content at 16 daa (0.730**), canopy temperature depression at 24 daa (0.704**) and above ground biological yield (0.748**). 49 physiological evaluation of wheat genotypes for tolerance table 7. relationship among the relative performances of physiological traits, grain yield and straw yield of different wheat genotypes relationship relative flag leaf chlorophyll content at 24 daa relative flag leaf relative water content at 16 daa relative flag leaf proline content at 16 daa relative kernel proline content at 16 daa relative flag leaf soluble sugar content at 16 daa relative canopy temperature depression at 24 daa relative grain yield relative above ground biological yield relative flag leaf chlorophyllcontent at 24 daa relative flag leaf relative water content at 16 daa 0.229 ns relative flag leaf proline content at 16 daa 0.455* 0.814** relative kernel proline content at 16 daa 0.300ns 0.863** 0.984** relative flag leaf soluble sugar content at 16 daa 0.345* 0.980** 0.912** 0.937** relative canopy temperature depression at 24 daa 0.446* -0.052 ns 0.539** 0.440* 0.147 ns relative grain yield 0.766** 0.584** 0.904** 0.813** 0.730** 0.704** relative above ground biological yield 0.665** -0.090 ns 0.482** 0.344* 0.111 ns 0.956** 0.748** 50 rana et al. fig. 3. stress susceptibility index of different wheat genotypes based on grain yield. fig. 4. stress susceptibility index of different wheat genotypes based on above ground biological yield. water stress susceptible index water stress susceptible index water stress susceptible index water stress susceptible index (ssi)(ssi)(ssi)(ssi) figure 3 shows stress susceptibility index of different wheat genotypes based on grain yield. baw 1170 showed the lowest water stress susceptibility index (0.81) this was followed by bari gom 25 (0.84) and e 28 (0.85). baw 1140 showed the highest water stress susceptibility index (ssi) value (1.42) (figure 4). these stress susceptibility index values indicated 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 bari gom 25bari gom 25bari gom 25bari gom 25 e 28e 28e 28e 28 baw 1170baw 1170baw 1170baw 1170 baw 1140baw 1140baw 1140baw 1140 s tr e ss su sc e p ti b ili ty i n d e x s tr e ss su sc e p ti b ili ty i n d e x s tr e ss su sc e p ti b ili ty i n d e x s tr e ss su sc e p ti b ili ty i n d e x b a se d o n g ra in y ie ld b a se d o n g ra in y ie ld b a se d o n g ra in y ie ld b a se d o n g ra in y ie ld wheat genotypeswheat genotypeswheat genotypeswheat genotypes 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 bari gom 25 e 28 baw 1170 baw 1140 s tr e ss su sc e p ti b ili ty i n d e x b a se d o n s tr e ss su sc e p ti b ili ty i n d e x b a se d o n s tr e ss su sc e p ti b ili ty i n d e x b a se d o n s tr e ss su sc e p ti b ili ty i n d e x b a se d o n a b o ve g ro u n d b io lo g ic a l y ie ld a b o ve g ro u n d b io lo g ic a l y ie ld a b o ve g ro u n d b io lo g ic a l y ie ld a b o ve g ro u n d b io lo g ic a l y ie ld wheat genotypeswheat genotypeswheat genotypeswheat genotypes 51 physiological evaluation of wheat genotypes for tolerance that baw 1170 was less susceptible genotype and baw 1140 was the most susceptible genotype. figure 4 also shows stress susceptibility index of different wheat genotypes based on above ground biological yield. the genotype baw 1170 showed the lowest water stress susceptibility index (0.86) which followed by e 28 (0.88) and bari gom 25 (1.08). baw 1140 showed the highest water stress susceptibility index (ssi) value (1.16). these stress susceptibility index values also indicated that baw 1170 was less susceptible genotype and baw 1140 was the most susceptible genotype. conclusionconclusionconclusionconclusion water deficit stress tolerant wheat genotypes showed greater stability of flag leaf chl, greater ability to retain water in leaf, higher level of proline in flag leaf and kernel, higher level of soluble sugar in flag leaf and greater ability to keep the canopy cooler compared to sensitive genotype under water deficit condition. greater spike dry matter accumulation at peak, longer grain growth duration, better yield components such as spikes m-2 and grains spike-1 under water deficit stress contributed to better tolerance of bari gom 25, e 28 and baw 1170. the order of tolerance based on grain yield was baw 1170 > bari gom 25 > e 28 > baw 1140 and the order of tolerance based on above ground biological yield was baw 1170 > e 28 > bari gom 25 > baw 1140. referencesreferencesreferencesreferences aggarwal, m., s. sharma, n. kaur, d. pathania, and k. bhandhari. 2011. exogenous proline application reduces phytotoxic effects of selenium by minimising oxidative stress and improves growth in bean (phaseolus vulgaris l.) seedlings. biol. trace elem. res. 140: 354-367. allakhverdiev, s. i., a. sakamoto, y. nishiyama, m. inaba and n. murata, 2000. ionic and osmotic effects of nacl-induced in activation of photo systems i and ii in synechococcus sp. plant physiol. 123: 1047–56. baque, m. a. 2003. potassium induced changes in the physiology of wheat plants (triticum aestivum l.) under water stress conditions. m.sc.(ag.) thesis, dept agron., bangabandhu sheikh mujibur rahman agril. univ., gazipur. bayoumi, t. y., m. h. eid and e. m. metwali. 2008. application of physiological and biochemical indices as a screening technique for drought tolerance in wheat genotypes. afr. j. biotechnol. 7: 2341-2352. bbs, 2016. yearbook of agricultural statistics of bangladesh, bangladesh bureau of statistics, ministry of planning, government of the people’s republic of bangladesh. 47 p. blum, a., l. shipiler, g. golan and j. mayer. 1989. yield stability and canopy temperature of wheat osmotic adjustment and growth of barley genotypes under drought stress. crop sci. 29:230-233. buttar, g. s., c. j. singh, m. s. ahuja and k. s. saini. 2005. canopy temperature: a method to estimate plant water stress and scheduling irrigation in cotton and wheat. j. agric. physics. 5(1): 79-83. 52 rana et al. chandrasekar, v., r. k. sairam and g. c. srivastava. 2000. physiological and biochemical responses of hexaploid and tetraploid wheat to drought stress. j. agron. crop sci. 185: 219-227. deora, v. s., m. a. a. shah and a. joshi. 2001. effect of moisture stress on wheat genotypes. crop, research, hisar. 21(1):24-26. farshadfar, e., m. ghasemi and f. rafii. 2014. evaluation of physiological parameters as a screening technique for drought tolerance in bread wheat. j. biodiv. environ. sci. 4: 175186. hasan, m. a., j. a. ahmed, m. m. bahadur, m. m. haque and s. sikder. 2007. effect of late planting heat stresss on membrane thermostability, proline content and heat susceptibility index of different wheat cultivars. j. nat. sci. foun. srilanka 35(2): 109-117. hasheminasab, h., m. t. assad, a. aliakbari and s. r. sahhafi, 2012. evaluation of some physiological traits associated with improved drought tolerance in iranian wheat. ann. biol. res. 2012;3:1719-1725. kameli, a. and d. m. loesel. 1993. . . . carbohydrates and water status in wheat plants under water stress. new phytol. 125: 609-614. karim m. a., a. hamid and s. rahman. 2000. grain growth and yield performance of wheat under subtropical conditions: ii. effect of water stress at reproductive stress. cereal res. comm. 28: 101-107. khakwani, a. a., m. d. dennett, m. munir and m. abid. 2012. growth and yield response of wheat varieties to water stress at booting and anthesis stages of development. pak. j. bot., 44(3): 879-886. kiliç, h. and t. yagbasanlar. 2010. the effect of drought stress on grain yield, yield components and some quality traits of durum wheat (triticum turgidum ssp. durum) cultivars. not. bot. hort. agrobot. cluj 38 (1): 164-170. motzo, r., f. giunta and m. deidda. 1996. relationships between grain filling parameters, fertility, earlines and grain protein of durum wheat in a mediterranean environment, field crops res. 47: 129-142. muller, a. g., 2001. modelagem da matéria seca e do rendimento de grãos de milho em relação à disponibilidade hídrica. tese doutorado em fitotecnia . porto alegre. nayyar, h. and d. gupta. 2006. differential sensitivity of c3 and c4 plants to water deficit stress: association with oxidative stress and antioxidants. environ. exp. bot. 58: 106-113. passioura, j. b., 2007. the drought environment: physical, biological and agricultural perspectives. j. expt. bot. 58(2): 113-117. shahram, m. d., k. moore and j. ollerenshaw. 2003. qualitative inheritance of water stress induced apical sterility in wheat (triticum aestivum l.). hereditas. 138: 237-240. sial, m. a., m. u. dahot, m. a. arain, g. s. markhand, m. h. naqvi, k. a. laghari and a. a. mirbahar. 2009. effect of water stress on yield and yield components of semi-dwarf bread wheat (triticum aestivum l.). pak. j. bot. 41 (4): 1715-1728. yoshida, s., d. a. forno, j. h. cpck and k. a. gomez. 1976. laboratory manual for physiological studies of rice (third edition).the international rice research institute, los banos, laguna, philipines. pp. 46-49. microsoft word 10 bangladesh agron. j. 2017, 20(2): 87-95 improvement of potatoimprovement of potatoimprovement of potatoimprovement of potato----jutejutejutejute----t.t.t.t.amanamanamanaman cropping pattern cropping pattern cropping pattern cropping pattern through inclusion of mungbeanthrough inclusion of mungbeanthrough inclusion of mungbeanthrough inclusion of mungbean a. k. chowdhury, t.a. k. chowdhury, t.a. k. chowdhury, t.a. k. chowdhury, t. zahanzahanzahanzahan****, m. m. anowar, m. k., m. m. anowar, m. k., m. m. anowar, m. k., m. m. anowar, m. k. islam, islam, islam, islam, s.s.s.s. h. molla and ah. molla and ah. molla and ah. molla and a....ssss....mmmm....mmmm.... rahman khanrahman khanrahman khanrahman khan bangladesh agricultural research institute, gazipur, bangladesh *corresponding author, e-mail: taslimazahan_tzp@yahoo.com (receivedreceivedreceivedreceived: 4 december 2017, accepted:accepted:accepted:accepted: 15 january 2018) keywords:keywords:keywords:keywords: four cropping pattern, crop diversity, food nutrition, production efficiency, yield improvement abstractabstractabstractabstract inclusion of mungbean in a cropping pattern not only increases the cropping intensity but also enriches soil health as well as ensures nutrition for the fast-growing population of bangladesh. a study was conducted in farmers’ field of domar, nilphamari, bangladesh during 2013-14 and 2014-15 to evaluate the performance of four-crop based cropping pattern potato – mungbean – jute t.aman rice against the existing farmer’s pattern potato-jute-t.aman rice. the experiment was laid out in randomized complete block design with six disperse replications. two-year study revealed that inclusion of mungbean and practice of better management along with use of modern high yielding varieties in the existing cropping pattern increased rice equivalent yield of the whole pattern by 38.7% and economic profit by 73.1%. moreover, land use efficiency and production efficiency of potato – mungbean – jute -t.aman pattern were higher than the existing pattern by 14.0 and 28.2%, respectively. thus, the study suggests incorporation of mungbean in the existing potato-jute-t.aman pattern could be a agronomically and economically profitable for the farmers as well as cropping intensity can be increased. introductionintroductionintroductionintroduction agriculture plays a great role in national economy of bangladesh and more than 70% of rural people are directly or indirectly involved with agriculture (bbs, 2016). this large sector engages nearly 45.6% of total labor force and contributes one sixth of gross national product of the country (bbs, 2016). now-a-days, agricultural economy of bangladesh is facing a great challenge to meet the food demand for the fast-growing population with its limit resources. despite of decreasing the cultivable land by 0.87% per year, presently bangladesh has achieved a remarkable increase in food production especially in case of rice production (bbs, 2016). the present cropping intensity of the country is 191%, but it needs to be increase significantly as the food requirement of the country people has projected to be doubled in the next 25 years. in bangladesh, continuous growing of rice is considered as the main reason of declining soil fertility as well as for irrigation water crisis. in addition, rice monoculture also reduces production of non-rice crops, erodes biodiversity and creates nutritional imbalance (hussain et al., 2001; rahman, 2010). potato – jute – t. aman rice is a major cropping pattern of greater rangpur region especially for medium high land (elahi et al., 1999). this pattern can easily be improved by inclusion of a short duration legume crop like mungbean. the inclusion of mungbean in a cropping system 88 molla & khan not only improves production of all crops grown in a rotation compared with monoculture systems (murray et al., 1987) but also reduces fertilizer requirement by fixing nitrogen in soil, improves soil health, increases potential yield with increased cropping intensity, greater productivity per unit time and space, and higher net returns (ali et al., 2012; naresh et al., 2013; hossain et al., 2015). therefore, the study had taken to evaluate the performance of the four-crop based cropping pattern and compare with farmers exiting pattern at domar, nilphamari. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the experiment was conducted at the farmers’ field during 2013-14 and 2014-15 to compare the performance of the improved cropping pattern (potato mungbean – jute t. aman) against the existing cropping pattern (potato-jute-t. aman) in the domar, nilphamari (latitude: 26005.778 n, longitude: 088050.41 e and altitude: 34 m). the experimental land was high land with sandy loam textured soil having ph 5.1. before starting the experiment, the land was neutralized by addition of dolomite @ 1 t ha-1. nutrient status of the initial soil and the post-harvest soil at completion of two years study has given in table 1. the experimental site received 1907.9 mm total rainfall in the year of 2013, 1635.0 mm in 2014 and 2417.0 mm in 2015 (figure 1a). monthly averaged maximum temperatures were ranged between 22.5-33.3° c in 2013, 22.2-34.3° c in 2014 and 22.4-32.3° c in 2015. the minimum temperatures were ranged from 9.1-26.8° c in 2013, 12.0-26.8° c in 2014 and 12.0-26.6° c in 2015. the lowest temperature was prevailed in the month of january during all the years of study whereas the temperature was at the peak in the month of june during 2013, in april during 2014 and in october during 2015 (fig. 1b). table 1. nutrient status of initial and post-harvest soil under potato-mungbean-jute-t.aman rice cropping pattern at domar, nilphamari nutrient status initial soil post-harvest soil ph 5.1 5.7 organic matter (%) 1.37 1.43 total n (%) 0.07 0.08 p (µg g-1 of soil) 27.2 31.6 s (µg g-1 of soil) 15.7 16.1 k (meq. per 100 g of soil) 0.11 0.10 zn (µg g-1 of soil) 0.9 1.04 b (µg g-1 of soil) 0.15 0.17 the experiment was laid out in randomized complete block design with 6 dispersed replications (one farmer represents one replication). the unit area for each farmer was 400 m2. data of the existing pattern were collected from the neighbor farmer’s practiced land of each replication. all agronomic management practices including dates of sowing/ transplanting and harvesting, seed rate, plant spacing, fertilizer management etc. were in table 2. in the existing pattern, farmers used potato var. bari alu-8 , jute var. indian tosa and t. aman var. swarna whereas bari alu-25, 0-9897 and brri dhan56 were used as potato, jute and t.aman rice varieties in the improved pattern (table 2). crop-wise recommended fertilizer packages were applied (frg, 2012). appropriate application methods of fertilizer were used for all the crops. irrigation, pest managements and other intercultural operations were done as 89 improvement of potato-jute-t.aman cropping pattern and when necessary. all field operations and management practices for both improved and existing patterns were closely monitored and recorded. aphid infestation was observed in potato field which was controlled by spraying acephate @ 1.5 g l−1 of water during 30 days after planting. dithane m-45 @ 4 g l−1 of water was applied for 5 times started from 30 dap and continued up to 70 dap at 10 days interval to control late blight disease of potato . mungbean field was sprayed with dimethoate @ 2ml l−1 of water at 3 days after emergence to control stem fly and emamectin benzoate was sprayed @ 2 ml l−1 of water to control pod borer. in t. aman rice, chlorpyrifos was applied @ 80 g ha-1 to control stem borer and tebuconazole (25%) was sprayed @ 2ml per l of water at 65 dat for controlling leaf blight. crop yield was recorded from the central 100 m2 area of each replication and converted into t ha-1. fig. 1. (a) monthly and yearly total rainfall and (b) monthly average temperature (maximum and minimum) of the experimental site of domar, niphamari during 2013-15 the collected data were analyzed statistically by following ‘anova’ technique and means were compared by dmrt using statistical package program mstat-c. economic analysis was done on the basis of prevailing local market price of the commodities. productivity of different cropping systems was compared in terms of rice equivalent yield (rey). rice equivalent yield (rey) was computed as yield of individual crop multiplied by market price of that crop divided by market price of rice. rice equivalent yield (t ha-1yr-1) = rice of pricemarket crop that of pricemarket crop individual of yield × land use efficiency (lue):land use efficiency (lue):land use efficiency (lue):land use efficiency (lue): it is worked-out on total duration of crops in an individual cropping pattern divided by 365 days (tomer and tiwari, 1990). it was calculated by the following formula: 0 200 400 600 800 1000 1200 1400 jan feb mar apr may june july aug sep oct nov dec r a in fa ll ( m m ) 2015 2014 2013 0 5 10 15 20 25 30 35 40 jan feb mar apr may june july aug sep oct nov dec t e m p e r a tu r e ( o c ) max. 2013 max. 2014 max. 2015 min. 2013 min. 2014 min. 2015 total in 2013: 1907.9 mm total in 2014: 1635.0 mm total in 2015: 2417.0 mm (a) (b) 90 molla & khan lue (%) = × 100 where, d1= duration of 1st crop of the pattern d2 = duration of 2nd crop of the pattern d3 = duration of 3rdcrop of the pattern d4= duration of 4thcrop of the pattern production efficiency (pe):production efficiency (pe):production efficiency (pe):production efficiency (pe): it values in terms of kg ha-1 day-1 was calculated by total main product in a cropping pattern divided by total duration of crops in that pattern (tomer and tiwari, 1990). it was calculated by the following formula: pe (%) = × 100 where, y1= yield of 1stcrop of the pattern y2= yield of 2nd crop of the pattern y3= yield of 3rd crop of the pattern y4= yield of 4th crop of the pattern d1= duration of 1st crop of the pattern d2= duration of 2nd crop of the pattern d3= duration of 3rd crop of the pattern d4= duration of 4th crop of the pattern the cost and return analysis included gross return, gross margin and marginal benefit cost ratio (mbcr). the output and inputs were valued at existing market prices. the mbcr of the farmer’s prevalent pattern and any replacement for it can be computed as the marginal value product (mvp) over the marginal value cost (mvc). the marginal of prevalent pattern (f) and any potential replacement (e) for it was computed as (cimmyt, 1988). marginal benefit cost ratio (mbcr) = mvc mvp = (f) tvc (e) tvc (f)return gross (e)return gross results and discussionresults and discussionresults and discussionresults and discussion nutrient status of soilnutrient status of soilnutrient status of soilnutrient status of soil soil nutrient analysis results demonstrated that no big change in amount of nutrient elements after completion of two-year cropping cycle (table 1). the study found a slight positive change in soil ph, om, n, p, s, zn and b. this positive change might be related to the supplementary supply of required amount of nutrients as fertilizers that were applied properly to achieve high yield goal. on the other hand, results showed a slight negligible decrease in total k after two years. field durationfield durationfield durationfield duration the study demonstrated that existing farmer’s pattern occupies the field for 303 days in 201314 and 298 days in 2014-15 leaving 61 days and 64 days as turnaround time, respectively (table 2). on the other hand, field duration of the improved cropping pattern was longer (341 days in 2013-14 and 344 days in 2014-15) than the existing pattern. however, four-crop base improved pattern reduced the turnaround time by 40 days in 2013-14 and 44 days in 2014-15 because of using short duration bari alu-25 and brri dhan56 as potato and t.aman rice d1+d2+ d3+d4 365 y1+y2+ y3+y4 d1+d2+ d3+d4 91 improvement of potato-jute-t.aman cropping pattern varieties. these two varieties helped to save 21-27 days and therefore it was easy to fit a short duration mungbean var.bari mung-6 within the improved pattern. yield performanceyield performanceyield performanceyield performance result showed that seed yield of potato in potato-mungbean-jute-t.aman cropping pattern (ip) was higher by 64.3% than that of in the existing farmer’s potato-jute-t.aman pattern (fp) (table 3). the average yield of potato in ip was 24.32 t ha-1 whereas it was only 14.80 t ha-1 in fp. it might be related to use of high yielding modern potato variety in ip along with improved management practices. on the other hand, the study revealed that fiber yield of jute and grain yield of t.aman rice were little bit lower in ip compared to fp. this might be happened due to use of short duration varieties of jute and t.aman rice. however, total yield of the whole pattern in ip was higher than fp by 42.1% in 2013-14 and 50.4% in 2014-15 as the additional yield of mungbean was obtained from the improved pattern (0.59 and 0/69 t ha1 in 2013-14 and 2014-15). rice equivalent yield (rey) of the improved cropping pattern (26.72 t ha-1yr-1) was also higher than the existing pattern (19.27 t ha-1yr-1) by 39% because high yield of potato and additional yield of mungbean with high market price helped the improve pattern to have higher rey over the existing pattern. production efficiency production efficiency production efficiency production efficiency higher production efficiency was calculated from four-crop base improved cropping pattern (24.40 kg ha-1 day-1) over the farmer’s existing three-crop based cropping pattern (19.03 kg ha-1 day-1) (figure 2). improved management practices and use of modern varieties lead the improved cropping pattern for higher production efficiency over the existing cropping pattern. production efficiency in farmers’ pattern was lower due to lack of modern management practices and local varieties. similar result was also found in the previous study of potato-rice base improved cropping patter (nazrul et al., 2013). land use efficiency land use efficiency land use efficiency land use efficiency land use efficiency depends on crop duration and number of crops cultivated during a cropping season. therefore, land use efficiency (lue) of the improved pattern (ip) was 93.84% whereas it was 82.33% in the existing pattern (fp). ip had higher lue than fp by 28.2% because total field duration of potato – mungbean – jute -t.aman pattern per year was longer (344 days) than potato-jute-t.aman pattern (291 days) (table 2). inclusion of mungbean in improved pattern helped to increase land use efficiency as it occupied field for 64-65 days. cost and return analysis cost and return analysis cost and return analysis cost and return analysis results of the economic analysis showed that total variable cost (tk.2,96,530 ha -1 ) was higher in the improved pattern than the existing pattern (tk.2,22,650 ha -1 ) because of additional cost involvement of mungbean cultivation. however, gross return (tk.4,40,805 ha -1 ) and gross margin (tk.1,64,975 ha -1 ) of the improved cropping pattern were higher than the existing pattern (gross return: tk.3,17,950 ha -1 and gross margin: tk.95,300 ha -1 ). moreover, mbcr of the improved pattern was calculated 1.66 indicates that inclusion of mungbean was 66% more economic beneficial than the existing farmer’s pattern. farmers’ opinionfarmers’ opinionfarmers’ opinionfarmers’ opinion farmers opined their satisfaction observing overall better performance of this improved pattern over existing cropping pattern but they needs favourable marketing environment. 92 molla & khan table 2. agronomic management practices of the existing cropping pattern and improved cropping pattern at domar, nilphamari during 2013-14 and 2014-15 pattern year existing cropping pattern improved cropping pattern crop potato jute t. aman potato mungbean jute t. aman variety bari alu-8 indian tosa swarna bari alu-25 bari mung-6 o-9897 brri dhan56 spacing 60cm×x 25cm broadcast 20cm×x 15cm 60cm×x25cm 30 cm broadcast 20cm×x 15cm fertilizer dose (n-p-k-s-znb kg ha-1) 120-50-11022-8-1 120-15-3010-0-0 114-9.8812.35-4-4-0 120-50-11022-8-1 45-90-30-41-1.19-0 90-15-3010-0-0 115-0-4015-0-2-0 date of sowing/ transplanting 2013-14 24 nov. to 08 dec. 2013 13 to 24 april 2014 21 to 28 july 2014 17 to 19 nov. 2013 20 to 26 feb. 2014 02 to 06 may 2014 12 to 16 aug. 2014 2014-15 20 nov. to 05 dec. 2014 08 to 19 april 2015 26 july to 07 aug. 2015 16 to 21 nov. 2014 21 to 27 feb. 2015 03 to 07 may 2015 10 to 13 aug. 2015 field duration 2013-14 94 94 115 87 64 99 91 2014-15 92 99 107 89 65 98 93 turnaround time 2013-14 11 45 5 6 8 4 3 2014-15 10 46 8 3 8 5 4 harvesting date 2013-14 26 feb. to 04 mar. 2014 16 to 25 july 2014 13 to 21 nov. 2014 12 to 17 feb. 2014 27 to 29 april 2014 09 to 13 aug. 2014 11 to 15 nov. 2014 2014-15 20 feb. to 06 mar. 2015 18 to 23 july 2015 10 to 20 nov. 2015 13 to 15 feb. 2015 27 to 30 april 2015 06 to 10 aug. 2015 11 to 16 nov. 2015 93 improvement of potato-jute-t.aman cropping pattern table 3. yield, variable cost, gross margin and marginal benefit cost ratio of the improved pattern and the existing pattern at domar, nilphamari during 2013-14 and 2014-15 pattern existing cropping pattern improved cropping pattern crop year potato jute t. aman potato mungbean jute t. aman grain or seed or fiber yield (t ha-1) 201314 15.1 2.28 3.68 23.73 0.59 2.21 3.39 201415 14.5 2.36 3.82 24.91 0.69 2.17 3.31 mean 14.80 2.32 3.75 24.32 0.64 2.19 3.35 straw or stick yield (t ha-1) 201314 5.78 4.23 5.78 4.23 201415 5.16 4.05 5.24 3.97 mean 5.47 4.14 5.51 4.10 rey (t ha-1yr-1) 201314 8.78 5.58 3.87 15.22 2.21 5.89 3.58 201415 9.16 7.02 4.13 14.26 2.45 6.21 3.62 mean 8.97 6.30 4.00 14.74 2.33 6.05 3.60 rey of the whole pattern (t ha-1yr-1) 19.27 26.72 gross return (tk. ha-1) 148000 103950 66000 243210 38400 99820 59375 total variable cost (tk. ha-1) 120630 57420 44600 146560 36100 62650 51220 gross margin (tk. ha-1) 27370 46530 21400 96650 23000 37170 8155 whole pattern gm (tk. ha-1) 95300 164975 mbcr (whole pattern) 1.66 price (tk. kg-1): urea-16, tsp-22, mp-15, gypsum-10, zinc sulphate-150, boric acid-160, rice grain-16.50, rice straw-1, jute fiber-33, jute stick-5, mungbean-60 and potato-10 rey: rice equivalent yield, mbcr: marginal benefit cost ratio, gm: gross margin 94 molla & khan fig. 2. land use efficiency and production efficiency of improved cropping pattern and the existing farmer’s pattern during 2013-14 and 2014-15 at domar, nilphamari conclusionconclusionconclusionconclusion cultivation of four-crop based potato – mungbean – jute -t.aman pattern is more profitable than the existing potato – jute t.aman pattern considering yield, financial benefit and also soil health. acknowledgementsacknowledgementsacknowledgementsacknowledgements principle author would like to acknowledge the funding authority bcct (climate change trust fund, bangladesh) for supporting this research. referencesreferencesreferencesreferences ali, r. i., t. h. awan, m. ahmed, m. u. saleem and m. akhtar. 2012. diversification of rice-based cropping systems to improve soil fertility, sustainable productivity and economics. j. animal plant sci. 22(1): 108-112. bbs. 2016. statistical yearbook of bangladesh. 35th edition, bangladesh bureau of statistics, statistics division, ministry of planning, government of the people’s republic of bangladesh. pp. 49-144. bjri. 1990. pater unnata jatshomuha, a booklet in bangla. bangladesh jute research institute, manik mia avenue, dhaka-1207. cimmyt. 1988. from agronomic data to farmer recommendation, an economics training manual. mexico, d.f. elahi, n. e., a. h. khan, m. r. siddique, a. saha, m. nasim, m. i. u. mollah and s. m. shahidullah. 1999. existing cropping patterns of bangladesh, potential technologies and strategies for improving systems productivity. in: proceedings of the workshop of modern rice cultivation in bangladesh, 14-16 february 1999. pp. 107-170. frg (fertilizer recommended guide). 2012. bangladesh agricultural research council, farmgate, dhaka-1215. hossain, m. m., m. begum, m. m. rahman and a. hashem. 2015. response of t. aman and boro rice to residue retention under strip tillage system. bangladesh agron. j. 18(2): 39-44. 0 15 30 45 60 75 90 105 2013-14 2014-15 l a n d u se e ff ic ie n c y ( % ) ip fp 0 5 10 15 20 25 30 2013-14 2014-15 p r o d u c ti o n e ff ic ie n c y (k g h a -1 d a y -1 ) 95 improvement of potato-jute-t.aman cropping pattern hussain, a. m. m., m. hossain and a. janaiah. 2001. hybrid rice adoption in bangladesh: socioeconomic assessment of farmers’ experiences. brac research monograph, series no. 18, brac, dhaka, bangladesh. murray, g. a., k. d. kephart, l. e. o’keeffe, d. l. auld and r. h. callihan. 1987. dry pea, lentil and chickpea production in northern idaho. coop. ext. serv. bulletin 664. moscow, id: university of idaho college of agriculture. 15p. naresh, r. k., purshottam and a. h. nanher. 2013. improving income and nutrition by incorporating mungbean in the presence of surface retained residues in rice-wheat cropping system. int. j. life sci. biotech. pharma res. 2(2): 158-164. nazrul, m. i., shaheb, m. r., khan, m. a. h. and a. s. m. m. r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16(2): 41-50. rahman, a. 2010. promoting financial inclusion for poverty reduction with inclusive growth. in: 17th biennial conference on ‘the economy at the golden jubilee of war of liberation: what type of bangladesh we would like to see?’ organized by bangladesh economic association held on 8 – 10 april, 2010, osmani memorial auditorium and institution of engineers, bangladesh dhaka. tomer, s. s. and a. s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35(1&2): 30-35. microsoft word 7 bangladesh agron. j. 2017, 20(2): 67-74 physiolophysiolophysiolophysiologicalgicalgicalgical traits traits traits traits and yield and yield and yield and yield performanceperformanceperformanceperformance of mungbean of mungbean of mungbean of mungbean ((((vigna radiatavigna radiatavigna radiatavigna radiata (l) wilczek) (l) wilczek) (l) wilczek) (l) wilczek) as influenced by light as influenced by light as influenced by light as influenced by light intensitiesintensitiesintensitiesintensities m. a. hossainm. a. hossainm. a. hossainm. a. hossain1111****, m. a. hasan, m. a. hasan, m. a. hasan, m. a. hasan2222,,,, s. sikders. sikders. sikders. sikder2222, a. k. , a. k. , a. k. , a. k. m. m. b. chowdhurym. m. b. chowdhurym. m. b. chowdhurym. m. b. chowdhury3333 and m. s. sarkerand m. s. sarkerand m. s. sarkerand m. s. sarker1111 department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur *corresponding author, e-mail: asmaulhstu@gmail.com (received: received: received: received: 30 may 2017, accepted:accepted:accepted:accepted: 25 july 2017) keywords: keywords: keywords: keywords: mungbean variety, chlorophyll, proline, yield abstractabstractabstractabstract an experiment was carried out at the crop physiology and ecology research field, hajee mohammad danesh science and technology university (hstu), dinajpur during the period from march to june 2016 to evaluate some physiological traits and yield performance of mungbean variety under different light intensities and to find out potential mungbean variety as intercrop. the experiment was laid out in a split -plot design with three replications. three light intensities (l100 full sunlight, l7575 % of full sunlight and l5050% of full sunlight) were assigned in the main plots and four varieties (barl mung-6, binamoong8, binamoong5 and bu mug-4) in the subplots. white and red colour mosquito nets were used for maintaining 75 and 50 percent of full sunlight. light percentages of mosquito nets were measured by light meter (21ye35). mosquito nets of different colors and pore size were used for maintaining 75 and 50 percent of full sunlight. the seed yield of bari mung-6 and binamoong8 performing well in under partial shade condition but the grain yield of binamoong5 and bu mug-4 was reduced drastically under partial shade condition. greater proline accumulation in leaf, higher leaf chlorophyll content, higher pods plant-1, higher seeds pod-1, greater seed size and better seed yield plant-1 under partial shade condition were contributed to better tolerance of bari mung-6 and binamoong8 under low light stress. introductionintroductionintroductionintroduction mungbean (vigna radiata (l) wilczek) is one of the important pulse crops in bangladesh. the agro ecological condition of bangladesh is quite favorable for growing the crop. the crop is usually grown in kharif-i and kharifii seasons with little or no inputs but it adds a lot to improve the soil health. mungbean (vigna radiata l.) has the potential to be used as profitable intercrop. but most of the grain legumes are sensitive to partial shading and often suffer from low light stress caused by associated tall crops (miranda-abilay and lantican, 1982). the reduction in light reaching the legume canopy when intercropped with maize was about 30 50% of the total incoming radiation and began around 30-35 days after maize seeding (polthanee and changsri, 1999; polthanee and treloges, 2002; 2003). shading causes decreasing of quantity and quality of the sun light intercept to the crop and it affects the productivity of the intercrops. yield reduction by shading depends upon crop species as well as the degree of shading. the degree of shading is generally controlled by the nature, age and characteristics of upper storied crops. the yield of soybean was decreased by 25 under 47% shade cover in the field (wahua and miller, 1978) and it was decreased by 30 under 40% artificial shade (lantican and catedral, 1977). in contrast under 40% artificial shade the yield of mungbean was decreased by 70% (lantican and catedral, 1977). 68 hossain et al. shading leads to phenotypic change in their photosynthetic apparatus (sundari, 2009). shading reduced photosynthesis due to increase in stomatal and mesophyll resistance, transpiration, partioning of biomass from vegetative parts to economic parts (nygren and killomaki, 1993). however, responses of mungbean to change in light intensity may vary in different genotypes. hence, developing variety adapted to low light condition is important and a need for selecting mungbean genotypes for shade tolerance. the mungbean genotypes could be the most tolerant and least decrease in grain yield, number of pods per plant, per cent leaf n and total stem n (wahua and miller, 1978). therefore, the present investigation was conducted to find out the effect of reduced light intensities on some physiological traits of different mungbean varieties and to find out the low light tolerant varieties of mungbean. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the experiment was conducted at crop physiology and ecology research field, hajee mohammad danesh science and technology university (hstu), dinajpur during the period from march to june 2016. the experiment was laid out in a splitplot design with three replications. three light intensity treatments (l100 full sunlight, l7575 % of full sunlight and l5050% of full sunlight) were assigned in the main plots and four varieties (bari mung-6, binamoong-8, binamoong5and bumug-4) in the sub-plots. white and red color mosquito nets were used for maintaining 75 and 50 percent of full sunlight. light percentages of mosquito nets were measured by light meter (21ye35). chlorophyll content of the flag leaf at 48 days after sowing was estimated according to witham et al. (1986). the proline content of the fully expanded youngest leaf was determined as bates et al. (1973). for collecting data on yield components ten plants from each experimental unit were selected randomly at flowering stage. at maturity, pods were harvested three times by hand pickings. the harvesting of mungbean pods was started at 60 days after sowing (das) and ended at 80 das. plant height, length of individual pod, pods plant-1, seeds pod-1, 1000-seed weight and yield plant-1 were also recorded from the ten randomly selected plants of each plot. the data were analyzed and the treatment means were compared using tukey’s test. results and discussionresults and discussionresults and discussionresults and discussion proline contentproline contentproline contentproline content the interaction of light intensities and mungbean varieties influenced the proline content of leaf significantly at 50 das (fig. 1). the maximum proline content was recorded in binamoong8 (0.91 µmoles g-1 fw) with 50% of full sunlight which was statistically identical to those recorded in bari mung-6 (0.82 µmoles g-1 fw) with 50% of full sunlight, binamoong 8 (0.79 µmoles g-1 fw) with 75% of full sunlight and binamoong5 (0.76 µmoles g-1 fw) with 100% of full sunlight. the loweer proline content was recorded in bu mug-4 (0.47 µmoles g-1 fw) with 100% of full sunlight which was statistically identical to bari mung-6 (0.53 µmoles g-1 fw) with 100% of full sunlight and bu mug-4 (0.61 µmole g-1 fw) with 50% of full sunlight. the results regarding proline content revealed that proline level was increased with the reduction in light levels in bari mung6, binamoong 8 and binamoong 5. in bu mug-4, proline content was increased at 75% of full sun light thereafter decreased at 50% of full sun light. 69 physiological traits and yield performance of mungbean fig.1. leaf proline content as influenced by light intensities and mungbean varieties at different days after sowing. means followed by different letter(s) differed significantly by tukey’s test at p ≤ 5% level of probability. l100 = 100 % of full sunlight (open field control), l75 =75 % of full sunlight, l50 = 50% of full sunlight chlorophyll contentchlorophyll contentchlorophyll contentchlorophyll content chlorophyll a content in leaf was not influenced significantly by the interaction effect of light intensities and mungbean varieties (table 1). numerically, maximum chlorophyll a (0.32 mgg-1) was obtained in bu mug-4 at l50 and the minimum (0.23 mgg -1) in binamoong5 at l75. chlorophyll b content in leaf was influenced significantly by the interaction effect where highest chlorophyll b (1.51 mgg-1) was observed both inbinamoong8 followed by bu mug-4 at l75, which was statistically similar to binamoog 8 (1.50 mgg-1) at l50, and binamoong 5 (1.47 mgg-1) at l50, and (1.39 mgg -1) of same variety at l100 and bu mug-4 (1.39 mgg -1) at l50. the lowest chlorophyll b was observed in bari mung-6 (1.24 mgg-1) at l100 which was statistically similar to those recorded in bu mug-4 (1.25 mgg-1) at l100, bari mung-6 (1.29 mgg-1) at l75, binamoong 8 (1.30 mgg -1)at l100, bari mung-6 (1.33 mgg -1) at l50 and binamoong 5 (1.34 mgg-1) at l75. similar trend was followed in chlorophyll a to b ratio. total chlorophyll content was influenced significantly by the interaction effect of light intensities and mungbean varieties (table 1). the maximum total chlorophyll (1.81 mgg-1) was observed in binamoong 8 at l50 whereas lower total chlorophyll was observed in bu mug-4 (1.49 mgg -1) at l100..the overall results in chlorophyll content indicated that total chlorophyll content was increased due to reduction in light intensities. the increase in total chlorophyll content under partial shade was mainly due to reduction in chlorophyll b content. as chlorophyll a content remained more or less unchanged due to partial shade the chlorophyll a to b ratio in bari mung-6, binamoong 8 and and binamoong 5 with l75 and remained unchanged with l50 but in bu mug-4 the ratio was remain unchanged l75 and increased with l50. islam et al. (1993) and, mirandaabilay and lantican (1982) found higher chlorophyll content in mungbean due to increased shading. total chlorophyll content was influenced significantly by the interaction effect of light intensities and mungbean varieties (table 1). the maximum total chlorophyll (1.81 mgg-1) was observed in binamoong 8 at l50 whereas lower total chlorophyll was observed in bu mug-4 (1.49 mgg -1) at l100..the overall results in chlorophyll content indicated that total chlorophyll content was increased due to reduction in light intensities. the increase in total chlorophyll content under partial shade was mainly due to reduction in chlorophyll b content. as chlorophyll a content 70 hossain et al. remained more or less unchanged due to partial shade the chlorophyll a to b ratio in bari mung-6, binamoong 8 and and binamoong 5 with l75 and remained unchanged with l50 but in bu mug-4 the ratio was remain unchanged l75 and increased with l50. islam et al. (1993) and, miranda-abilay and lantican (1982) found higher chlorophyll content in mungbean due to increased shading. table 1. chlorophyll a, chlorophyll b, chlorophyll a to b ratio and total chlorophyll content of leaf as influenced by light intensities and mungbean varieties variety light level chl a (mgg-1) chl b (mgg-1) chl a to b ratio total chl (mgg-1) bari mung6 l100 0.27 1.24 e 0.22 ac 1.50 cd l75 0.25 1.29 ce (4.03) 0.20 bd (-9.09) 1.54 bd (2.67) l50 0.28 1.33 be (7.23) 0.22 ac (0.00) 1.60 ac (6.67) binamoong8 l100 0.27 1.30 ce 0.21ab 1.56 ad l75 0.27 1.51 a (16.15) 0.18 cd (-14.29) 1.78 a (14.10) l50 0.31 1.50 a (15.38) 0.21ab (0.00) 1.81 a (16.03) binamoong5 l100 0.28 1.39 ac 0.20 bd 1.66 ab l75 0.23 1.34 be (-3.60) 0.17 d (-15.00) 1.57 ad (-5.42) l50 0.29 1.47 ab (5.76) 0.20bd (0.00) 1.76 ab (6.02) bu mug4 l100 0.25 1.25 de 0.20 bd 1.49d l75 0.30 1.51 a (20.80) 0.20bd (0.00) 1.81 a (21.48) l50 0.32 1.39 ac (11.20) 0.23 a (15.00) 1.71 ab (14.77) cv(%) 9.97 3.43 4.34 2.92 in a column, means followed by different letter(s) differed significantly by tukey’s test at p ≤ 5% level of probability. l100 = 100 % of full sunlight (open field control), l75 = 75 % of full sunlight, l50 = 50% of full sunlight number of pods plantnumber of pods plantnumber of pods plantnumber of pods plant----1111 the interaction effect of light intensity and mungbean varieties on number of pods plant-1 was significant (table 2). the maximum number of pods plant-1 (10.00) was observed in bari mung-6 with 100% of full sunlight, which was statistically similar to those recorded in bina moong 5 (9.90) with 100% of full sunlight, binamoong 8 (9.63) with 75% of full sunlight, bari mung-6 with 75% (9.57) and 50% (9.27) of full sunlight, binamoong 8 with 50% (9.07) and 100% (8.97) of full sunlight and bu mug-4 with 100% of full sunlight (8.93). the minimum number of pods plant-1 was observed in bu mug-4 with 50% of full sunlight (6.07) which was statistically similar to that recorded in binamoong 5 with 75% of full sunlight (7.03). percent change from l100 values indicated that the number of pods plant -1 was reduced with reduction in light intensities in bari mung-6, binamoong 5 and bu mug-4 but it was even increased in binamoong 8 under low light intensities. the reduction in number of pods plant-1 71 physiological traits and yield performance of mungbean with the reduction of light intensities was more in biinamoong and bu mug-4 than that in bari mung-6. table 2. yield attributes of mungbean as influenced by light intensities and varieties variety light level pods plant-1 seeds pod-1 1000-seed wt (g) seed yield (g plant-1) bari mung6 l100 10.00 a 8.57 ef 45.20 b 3.07 a l75 9.57 ab (-4.30) 9.15 bc (6.77) 47.23 a (2.03) 3.07 a (0.00) l50 9.27 ab (-7.30) 9.03 bd (5.37) 44.00 b (-2.65) 2.89 ad (-5.86) binamoong 8 l100 8.97 ab 8.08 g 45.28 b 3.01 ac l75 9.63 ab (7.35) 8.62 ef (6.68) 44.09 b (-2.63) 2.86 bd (-4.98) l50 9.07 ab (1.11) 8.40 fg (3.96) 45.11 b (0.38) 2.84 cd (-5.64) binamoong5 l100 9.90 a 9.20 bc 38.26 d 2.89 ad l75 7.03 de (-28.99) 9.32 b (1.30) 38.91 d (1.70) 2.47 e (-14.53) l50 7.70 cd (-22.22) 8.95 cd (-2.72) 40.49 c (5.83) 2.28 e (-21.11) bu mug4 l100 8.93 ac 9.20 bc 45.40 b 3.00 ac l75 8.27 bd (-7.39) 9.73 a (5.76) 41.87 c (-9.85) 2.75 d (-8.33) l50 6.07 e (-32.03) 8.78 de (-4.56) 41.65 c (-8.26) 2.02 f (-32.67) cv (%) 5.97 1.25 1.26 2.66 in a column, means followed by different letter(s) differed significantly by tukey’s test at p ≤ 5% level of probability. l100 = 100 % of full sunlight (open field control), l75 = 75 % of full sunlight, l50 = 50% of full sunlight number of seeds podnumber of seeds podnumber of seeds podnumber of seeds pod----1111 the interaction effect of light intensities and mungbean varieties on number of seeds pod-1 was significant (table 2). the maximum number of seeds pod-1 was recorded in bu mug-4 (9.73) with 75% of full sunlight, which was followed by all other treatment combinations. the lowest number of seeds pod-1 was recorded in binamoong 8 (8.08) with 100% of full sunlight, which was statistically similar to same variety (8.40) with 50% of full sunlight. percent change from control (l100) values indicated that the number of seeds pod -1 was increased with reduction in light levels in bari mung-6 and binamoong 8. on the other hand, in binamoong 5 and bu mug-4 it was increased in 75% of full sunlight but decreased in 50% of full sunlight. thousand thousand thousand thousand seeds seeds seeds seeds weight weight weight weight the interaction effect of light intensities and mungbean varieties on thousand seeds weight was significant (table 2). the maximum seeds weight was observed in bari mung-6 (47.23 g) at l75, which was followed by all other treatment combinations while lowest seeds weight was observed in binamoong5 (38.26 g) at l100, which was statistically similar to same variety (38.91 g) at l75. the results showed that increased or remained more or less unchanged due to 72 hossain et al. low light intensities in bari mung-6, binamoong 8 and binamoong5 but it was reduced with the reduction in light intensities in bu mug-4. seed seed seed seed yield yield yield yield the interaction effect of light levels and mungbean varieties on seed yield plant-1 (table 2) and seed yield were significantly influenced (fig.2). the maximum seed yield plant-1 was observed in bari mung-6 (3.07 g) both at l100 and l75, which was statistically similar to those obtained from binamoong 8 (3.01 g) at l100, bu mug-4 (3.00 g) at l100, bari mung-6 (2.89 g) at l50 and binamoong (2.89 g) at l100. the lowest seed yield plant -1 was observed in bu mug-4 (2.02 g) at l50. these results indicated that the seed yield plant 1 was remain unchanged or decreased with the reduction in light levels but the reduction was more in binamoong 5and bu mug-4 than in bari mung-6 and binamoong8. the maximum seed yield per hectare was recorded in bu mug-4 with 100% of full sunlight (0.94 t ha-1) which was statistically similar to those recorded in binamoong 8 with 100% of full sunlight (0.90 t ha-1). lower grain yield per hectare was recorded in bu mug-4 with 50% of full sunlight (0.52 t ha-1) which was statistically similar to binamoong 5 with 50% of full sunlight (0.60 t ha-1). fig. 2. seed yield (t ha-1) as influenced by light intensities and mungbean varieties at different days after sowing. means followed by different letter(s) differed significantly by tukey’s test at p ≤ 5% level of probability. l100 = 100 % of full sunlight (open field control), l75-= 75 % of full sunlight, l50 = 50% of full sunlight the results in seed yield per hectare also indicated that the yield was remained statistically unchanged due to lower light levels in bari mung-6 and binamoong 8 but in binamoong 5 and bu mug-4, the seed yield was reduced with the reduction in light levels. seed yield of mungbean is attributed by number of pods, number of seeds per pod and seed size. these yield attributes were severely affected by degree of shading. lantican and catedral (1977), laosuwan et al. (1992) and miranda-abilay and lantican (1982) observed lower seed yield for shaded grown mungbean plant. polthanee et al. (2011) showed that seed yield of soybean was significantly (p < 0.05) decreased under the low light intensity at 30% of natural light both in wet and dry season. akhter et al. (2009) reported reducing the light intensity from 100 to 25% exerted variable quantity of reduction of dry seed yield plant-1 in different genotypes and the reduction of seed yield plant-1 was attributed to lower pod plant-1, seed pod-1 and smaller weight seed. islam (1995) found pods per plant decreased with the increase of shading. 73 physiological traits and yield performance of mungbean stover yield plantstover yield plantstover yield plantstover yield plant----1111 the interaction effect of light levels and mungbean varieties on stover yield per plant was significant (table 3). the maximum stover yield per plant was observed in binamoong8 (6.71 g) at l50 which was statistically similar to bari mung-6 (6.05 g) at l50, binamoong 8 (5.81 g) at l75, bina mung-5 (5.44 g) at l100, bu mug-4 (5.33 g) at l75 and (5.20 g) at l50, binamoong 5 (4.98 g) at l75, bu mug-4 (4.93 g) at l100 and bari mung-6 (4.77 g) at l100. the lowest stover yield per plant was observed in binamoong 8 (3.41 g) at l100 which was statistically similar to in bari mung-6 (3.65 g) at l75, binamoong 5 (4.20 g) at l50, bari mung-6 (4.77 g) at l100, bu mug-4 (4.93 g) at l100, binamoong 5 (4.96 g) at l75, bu mug-4 (5.20 g) at l50 and (5.33 g) at l75 and binamoong 5 (5.44 g) at l100. harvest index (%)harvest index (%)harvest index (%)harvest index (%) the interaction effect of light levels and mungbean varieties on harvest index was significant (table 3). the maximum harvest index was observed in binamoong-8 (88.27) at l100 which was statistically similar to observed in bari mung-6 (84.11) at l75. the lowest harvest index was observed in bu mug-4 (38.85) at l50 which was statistically similar to those observed in binamoong 8 (3.65 g) at l50 and bari mung-6 (47.77) at l50. table 3. stover yield and harvest index of mungbean as influenced by light levels and varieties variety light level stover yield (g plant-1) harvest index (%) bari mung6 l100 4.77 ad 64.36 b l75 3.65 cd (-23.48) 84.11 a l50 6.05 ab (26.83) 47.77 de binamoong8 l100 3.41 d 88.27 a l75 5.81 ac (70.38) 49.23 d l50 6.71 a (96.77) 42.23 e binamoong5 l100 5.44 ad 53.13 c l75 4.96 ad (-8.82) 49.80 d l50 4.20 bd (-22.79) 54.29 c bu mug4 l100 4.93 ad 60.85 bc l75 5.33 ad (8.11) 51.60 cd l50 5.20 ad (5.48) 38.85 ef cv (%) 14.34 4.56 in a column, means followed by different letter(s) differed significantly by tukey’s test at p ≤ 5% level of probability. l100 = 100 % of full sunlight (open field control), l75 = 75 % of full sunlight, l50 = 50% of full sunlight 74 hossain et al. conclusionconclusionconclusionconclusion the seed yield of mungbean var. bari mung-6 and binamoong8 performing well in under partial shade condition but the seed yield of binamoong5 and bu mug-4 was reduced drastically under partial shade condition. greater proline accumulation in leaf, higher leaf chlorophyll content, higher pods plant-1, higher seeds pod-1, greater seed size and better seed yield plant-1 under partial shade condition were contributed to better tolerance of bari mung-6 and binamoong8 under low light stress. referencesreferencesreferencesreferences akhter, n., m. m. rahman, m. hasanuzzaman and k. nahar. 2009. physiological response of garden pea (pisum sativum l.) grown under different light environment. bot. res. int. 2 (4): 304-309. bates, l. s., r. p. waldron and i. d. teare. 1973. rapid determination of free proline for water stress studies. plant soil 39: 205-207. islam, s. m. t., f. kubota, m. f. h. mollah and w. agata. 1993. effect of shading on the growth and yield of mungbean (vigna radiata l. wilczek). j. agron. crop sci. 171: 274–278. lantican, r. m. and i. g. catedral. 1977. evaluation of legumes for adaptation to intensive cropping systems. i. mungbean (vigna radiata l. wilczek). philippine j. crop sci. 2: 6266. laosuwan, p., s. saengpratoom, s. kaloowong and a. thongsomsni. 1992. breeding mungbean for shade tolerance, in "proceedings of mungbean meeting", chiang mai. thailand. pp. 95100. miranda-abilay, r. and r. m. lantican. 1982. characters associated with yield performance of grain legume crops under partial shaded condition i. mungbean (vigna radiata). philippine j. crop sci. 7(2): 88-93. nygren, m. and s. killomaki. 1993. effect of shading on leaf structure and photosynthesis in young birches. forest ecol. manag. 7(2) : 119-132. polthanee, a. and r. changsri. 1999. effect of planting dates of mungbean on growth and yield in corn mungbean relay cropping under rainfed conditions in an up-land area of northeastern thailand. thai j. agric. sci.32: 187-196. polthanee, a. and v. treloges. 2002. growth and yield of mungbean cultivars in mungbean-corn relay inter-cropping systems. j. inter. soc. southeast asian agric. sci. 8: 1-14. polthanee, a. and v. treloges. 2003. growth, yield and land use efficiency of corn and legumes grown under intercropping systems. plant prod. sci. 6: 139-146. polthanee, a., k. promsaena and a. laoken. 2011. influence of low light intensity on growth and yield of four soybean cultivars during wet and dry seasons of northeast thailand. agric. sci. 2(2): 61-67. sundari, t. 2009. morphological and physiological characteristics of shading tolerant and sensitive mungbean genotypes. hayati j. bio. sci. 16(4): 127-134. wahua, t. a. t and d. a. miller. 1978. effects of shading on the n2–fixation, yield, and plant composition of field-grown soybeans. agron. j. 70: 387-392. potentiality of local and exotic sweetpotato leaves bangladesh agron. j. 2018, 21(2): 49-58 exploring the potential of local and exotic sweet potato leaves as vegetables m. a. s. hossain*1, a. f. m. s. islam2, m. n. h. miah3 and m. m. h khan4 1 regional laboratory, soil resource development institute, sylhet-3100 2dept. of crop botany and tea production technology, sylhet agricultural university sylhet-3100 3dept. of agronomy and haor agriculture, sylhet agricultural university sylhet-3100 4dept. of biochemistry and chemistry, sylhet agricultural university, sylhet-3100 *corresponding author, email: mashossain75@gmail.com (received: 22 october 2018, accepted: 16 february 2019) keywords: organoleptic properties, nutrition, phenolic compounds, tannin abstract an experiment was conducted at farmer’s field of dashpara village of sylhet sadar upazila during 2016-2017 to find out nutritional status of the leaves of four local and four exotic lines of sweet potato. d. the lines and variety were local-1, local-2, local-5, local-8, exotic-1, exotic2, exotic-3, exotic-4 and bari sp-4.the experiment was conducted by in a randomized complete block design. crude protein, crude fat, crude fiber, total ash, moisture and carbohydrate were determined by proximate analysis whereas elemental nutrients, total sugar, starch, vitamin c, phenolic compounds and tannins were determined by the procedure outlined by association of analytical chemists’ (aoac). ninety days old fresh leaves were collected from the experimental field for chemical analysis. results revealed that the highest percent of carbohydrate (by difference), crude protein, crude fat, total ash and energy were in exotic2 (65.47), local-2 (26.59), local-5 (3.63), bari sp-4 (8.35) and local-1 (370.4 kcal 100 g-1), respectively. the highest percent of crude fiber, total sugar and starch were recorded in local-8 (17.79), local-2 (5.63) and local-8 (36.42), respectively. the local-1 contained the highest amount of phenolic compounds and tannins while vitamin c was in local-5 and local-8. it was also observed that sweet potato leaves of local-1, local-5 and local-8 contained appreciable levels of iron, zinc, calcium, magnesium, potassium and phosphorus. it can be concluded that the leaves of local-1, local-5, local-8, exotic-1 and exotic-2 could be suitable for vegetables and can be included as supplement our daily nutrient requirements. introduction sweet potato is one of the diversified root crops supplying huge energy as well as vitamins and minerals. leaves are rich in vitamin b, beta-carotene, iron, calcium, zinc and protein (islam, 2014). fresh leaves contain vitamin a on an average of 1600 iu 100g-1 (bhuiyan et al., 2008). leaves are very nutritious compared to leaves of cassava, amaranth, mushrooms, taro and pumpkin (oduro et al., 2008). it grows well in marginal lands namely char lands, homestead areas, the valley of low hills, newly accreted lands and even problematic soils namely saline belts, acidic soils. it requires a low amount of fertilizers and agricultural inputs with low management practices. sweet potato is perennial and its rapid growing tops (leaves and tender vines) can be harvested several times in a year; their annual yield is much higher than many other green vegetables (islam, 2006). about:blank 50 hossain et al. the present study area is the north-eastern part of bangladesh. there are 396,951 ha of land remains uncultivated during rabi and kharif seasons in sylhet region (dae, 2014). during summer and rainy season, vegetable production is very limited. the price of different vegetables is relatively high due to low production and availability in this region. people are mostly dependent on import vegetables from other parts of bangladesh; hence they have limited chances to take sufficient vegetables. consequently, people especially women and children are suffering from hidden hunger especially micronutrient deficiency. about 57% poor people of sylhet region are living in food insecurity (bdsh, 2014). moreover, adverse climatic conditions like heavy rainfall, high humidity, seasonal flooding along with soil acidity etc. are the obstacles for the r crop production in this region. in this context, cultivation of sweet potato in the summer and rainy seasons may help to produce leafy vegetables readily available in the markets for the consumers. furthermore, there are several indigenous sweet potato genotypes are available in the region. though some of them are being cultivated by farmers’ sporadically around the river banks, valley areas and homestead areas; but the nutritional quality assessment as vegetables has not yet done. knowledge of the phenolic components and antioxidant activity of sweet potato greens may increase the awareness of the food industry as well as consumers in utilizing sweet potato greens for functional food. considering the above facts, the research work was taken to estimate the nutrients composition of leaves of nine sweet potato genotypes, to estimate total sugar, starch, crude fiber, vitamin c content, phenolic compounds, tannins, and mineral nutrients and to establish their suitability as vegetables. materials and methods conduction of field experiment and collection of samples the experiment was conducted at farmer’s field of dashpara village of sylhet sadar upazila during november 2016 to march 2017. nine sweet potato genotypes namely local-1, local-2, local-5, local-8, exotic-1, exotic-2, exotic-3, exotic-4 and bari sp-4 were used as planting materials. the experiment was conducted in a randomized complete block design (rcbd). the experimental field was fertilized with manures and fertilizers as per soil test based (stb) of frg (2012). cowdung, urea, tsp, mop, gypsum, solubor, zinc sulfate (hepta), magnesium sulfate and dolomite were applied @ 5000, 224, 186, 165, 28, 2, 9, 79 and 988 kg ha-1, respectively. before final land preparation, half of urea and mop, full of other fertilizers and cow dung were applied. rest of urea and mop were applied as side dressing at 35 days after planting during earthing up operation. soil reaction (ph) was corrected by dolomite application prior to 15 days of planting. the unit plot size was of 4.8 m  4.2 m with a block to block distance 1.0 m and plot to plot distance 0.6 m. raised beds were prepared and cuttings of sweet potato vines were planted in lines maintaining row to row 60 cm and plant to plant 30 cm. weeding was done as and when necessary. irrigation was done at 30 and 60 days after planting (dap). organoleptic properties of tops (leaves and tender vines) were evaluated at field. after 90 days of planting, unfolded leaves of sweet potato were collected into poly bags from the experimental field with proper tagging and brought them into the laboratory. leaves were washed with distilled water and left them sometimes to drip out excess moisture. after that fresh weight was taken with electric exploring the potential of local and exotic sweet potato balance. weighed samples were dried at 60 °c in an oven (gallenkamp hot box) for 24 hours (anita et al., 2006), cooled and then dry weight and moisture percent were calculated. they were ground properly and preserved in a plastic pot with labeled for chemical analysis. methods of analysis of nutrients moisture percent of ground leaves were further assayed by perten instruments ab (da7200) digitally prior to chemical analysis. nitrogen percent was determined by micro-kjeldahl method as stated by sadasivam and manickam (1997) following digestion, distillation, and titration. protein percent was calculated by multiplying the nitrogen percent with 6.25. crude fat was determined by foss soxtec 2046 apparatus (soxtech extractor) using petroleum ether (b.p. 40-60 °c) with a known weight of the sample after completing boiling, rinsing and exhaustive extraction steps. total ash was determined by incineration of a known sample in a muffle furnace (nabertherm trade mark, germany) at 550 °c for 24 hours as per ranganna (1991). the carbohydrate content was determined by subtracting the moisture, crude protein, crude fat and total ash percentage from the total dry matter (100) as described by law (2002). the calorific value was estimated by summing the multiplied values for crude protein, crude fat and carbohydrate (excluding crude fiber) by their respective atwater factors (4, 9 and 4, respectively, merrill and watt, 1973). total sugar and starch content were determined calorimetrically with anthrone reagent based on the method of mccready et al. (1950). glucose content was found out in the sample using the standard graph and multiplied the value by a factor 0.9 to arrive at the starch content. crude fiber was obtained from the loss in weight on ignition of dried residue (550 °c for 6 hours) remaining after digestion of fat free samples with 1.25% each of sulphuric acid and sodium hydroxide solutions under specified condition. the folin-ciocaltue method (singleton and rossi, 1965) as described by makkar (2003) was used to determine total phenolics. tannic acid was used as standard and the results obtained were expressed as mg tannic acid equivalent 100g-1 dry matter. tannins were determined according to makkar (2003) with some modifications using the formula: tannins (mg poly ethylene glycol equivalent 100g-1) = total phenol before using tannic acid -total phenol after using poly ethylene glycol (peg). vitamin c was determined as stated by aoac official method (2012). vitamin c was extracted by 3% metaphosphoric acid and acetic acid solution maintaining 1:200 ratio followed by titration with 2, 6 dichlorophenol indophenol. for colored sample the ratio of sample and extractants was 1:400. for estimation of p, k and elemental nutrients, samples were digested with di-acid mixture (hno3:hclo4 = 5:1) at 120-200 °c for 2 hours for achieving transparent solution as per fang (1991). after cooling, the digested samples were filtered using whatman no. 42 filter paper and diluted. phosphorus concentration was determined colorimetrically by spectrophotometer using ammonium molybdate-ascorbic acid solution blue color method (peterson, 2002). potassium (k), calcium (ca) and magnesium (mg) concentration was determined by atomic absorption spectrophotometer using lacl3 solution, whereas iron (fe) and zinc (zn) concentration was determined directly by atomic absorption spectrophotometer as stated by yoshida et al. (1976). duncan’s multiple range test (dmrt) was followed by using mstatc package. 50 hossain et al. results and discussion assessment of organoleptic properties of tops (leaves and tender vines) tops of local-1, local-5, local-8, exotic-1, exotic-2 and exotic-4 were green (table1). tops of local-2, exotc-3 and exotic-4 were purple. soft and succulent tops were observed in local-1, local-5, local-8, exotic-2, exotic-3 and exotic-4 genotypes, while local-2, exotic-1 and bari sp-4 had soft-hard tops. petioles (stalk of leaves) of all of the genotypes were green. long, thick and soft petioles were in exotic-4 where exotic-1 had long, thick and soft-hard petioles. medium, thick and soft petioles were in local-1, local-8, exotic-2 and exotic-3. local-2 had short, thick and soft-hard petioles. local-5 and bari sp-4 had short and soft petioles. these variations are perhaps due to genetic as well as environment. the above results agree with the observations of islam (2006), where he added that sweet potato tops, could serve as an additional leafy green vegetable. acceptable tops should be tender, glabrous and purplish. those eating tops prefer the top 10 cm of tips including both stem and leaves. tips with the largest number of leaves with petioles less than 4/10 of an inch (1 cm) long are considered desirable because they are tender and good for vegetables. petiole length varies widely with genotype and may range from approximately 10 to 40 cm (huaman, 1992). table 1. organoleptic properties of tops of nine sweetpotato genotypes genotypes color of tops softness of tops (tender leaves and vines) petiole color thickness and softness of petiole local-1 green soft and succulent green medium, thick, soft local-2 purple soft-hard green short, thick, soft-hard local-5 green soft and succulent green short, thick, soft local-8 green soft and succulent green medium, thin, soft exotic-1 green soft-hard green long, thick, soft-hard exotic-2 green soft and succulent green medium, thick, soft exotic-3 purple soft and succulent green medium, thin, soft exotic-4 green soft and succulent green long, thick, soft bari sp-4 purple soft-hard green short, thin, soft nutritional assessment of leaves moisture (%) the highest moisture percent in fresh leaves were in exotic-3 (84.43) followed by local-8, exotic-1, exotic-2 and bari sp-4, and the lowest was in both local-1 (80.82 %), local-2 and local-5 (table 2). the highest moisture percent in sample powder was in local-5 (8.13) and the lowest in local-1 (6.56). the above results were supported by several authors. anita et al. (2006) reported moisture content from 82.21 to 87.48%, whereas usda (2009) reported from 80 to 88% and oduro (2008) from 80.16-88.20%. foods with high moisture content are more prone to perishability (fennema and tannenbaum, 1996). several authors have reported that the application of fertilizer reduces the moisture content in the sweepotato. the low moisture content signifies a high dry matter content and, thus, more carbohydrates and, consequently, a higher energy content (gichuhi, 2014). carbohydrate (%) exploring the potential of local and exotic sweet potato carbohydrate content in leaves of sweet potato had significant variations in genotypes (table 2). the highest carbohydrate percentage (by difference) was in exotic-3 (65.47) followed by exotic-2, local-2 and exotic-1. the lowest percentage (56.68) was in local-5. carbohydrate content in leaves of local-1, local-8 and bari sp-4 were similar. local-5, local-8 and exotic-4 contained lower percent of carbohydrate than check variety. the carbohydrate content in leaves are greater than the report of usda (2009) and uduro (2008) where carbohydrate ranged from 53 to 59%, and 53.29 to 59.01%, respectively. except for local-5 all of the genotypes performed better in carbohydrate content. crude protein (%) crude protein varied significantly from genotype to genotype (table 2). the maximum protein percentage was in local-8 (26.59) followed by local-1 (6.31). crude protein percentage among local-5, exotic-4 and exotic-1 were similar. the lowest protein percentage was in exotic-2 (19.97). all of the genotypes performed better over check variety except exotic-2. the studied result agrees with the finding of usda (2009) and uduro (2008), while anita et al. (2006) found protein in leaves of 24.9%. protein levels in the leaves of sweetpotato are higher than in their respective storage roots, but the amount of leaves consumed by humans limits their total contribution (low et al., 2009). crude fat (%) the highest crude fat percent was in local-5 (3.63) followed by local-1 (2.75), exotic-2 (2.84) and exotic-4 (2.82) (table 2). the lowest fat percent was in exotic-3 (2.05). fat percent of local-2, exotic-1 and bari sp-4 were statistically similar. crude fat percent of local-5, local-1, local-2, exotic-2 and exotic-4 was higher than that of check variety. table 2. proximate analysis and energy in leaves of sweetpotato genotypes moisture in fl (%) moisture in dl (%) carbohy drate (%) crude protein (%) crude fat (%) total ash (%) energy (kcal 100g-1) local-1 80.82 b 6.56 e 61.22 c-e 25.20 ab 2.75 b 4.26 e 370.4 a local-2 81.27 b 6.73 de 63.14 bc 22.72 c 2.68 bc 4.73 de 367.5 ab local-5 81.24 b 8.13 a 56.68 f 24.38 bc 3.63 a 7.18 b 356.9 e local-8 82.64 ab 7.20 bc 59.48 e 26.59 a 2.35 cd 4.38 e 365.5 bc exotic-1 82.80 ab 7.00 cd 62.44 b-d 23.44 bc 2.63 bc 4.49 e 367.2 ab exotic-2 83.08 ab 7.50 b 64.43 ab 19.97 d 2.84 b 5.26 d 363.2 cd exotic-3 84.43 a 7.26 bc 65.47 a 20.66 d 2.05 d 4.56 e 362.9 cd exotic-4 83.10 ab 7.20 bc 59.40 e 24.44 bc 2.82 b 6.14 c 360.8 d bari sp4 82.70 ab 7.50 b 60.92 de 20.60 d 2.63 bc 8.35 a 349.7 f mean 82.94 7.23 61.46 23.11 2.710 5.48 362.68 cv (%) 1.26 2.12 1.31 3.22 5.52 4.65 0.36 fl= fresh leaves, dl = dry leaves, bari sp-4 was check variety. figures with dissimilar letters in a column differ significantly at dmrt0.01 crude fat percent of the leaves of the studied genotypes were less than the finding of anita et al. (2006) where they found 4.9% fat in leaves and greater than that of uduro (2008) where he reported from 0.38-1.91% and usda (2009) reported from 0.4 -2%. variations may be genotypic as well as the methodology used in the fat determination. 50 hossain et al. total ash (%) total ash of the studied genotypes ranged from 4.26 (local-1) to 8.35% (local5). bari sp-4, local-5 and exotic-4 showed better in total ash content (table 2). the above results comparatively lower to that of usda (2009) and anita et al. (2006); where they reported ash content from 8 to 11.6%. several authors have observed an increased concentration of minerals in the sweet potato leaves and storage roots with the increased application of fertilizer (agbede, 2010). the ash content of sweet potato varieties can be influenced by soil, climatic conditions, etc. (abbasi et al., 2011). energy (kcal 100 g dry leaves-1) the leaves of local-1, exotic-1, local-2 and local-8 were performed better in energy producing (table 2). the higher energy was recorded in local-1 (370.4) followed by local-2 (367.5) and exotic-1 (367.2). the lowest energy was observed in bari sp-4 (349.7). the results partially agree with the finding of anita et al. (2006). total sugar (%) total sugar percent in leaves was influenced by genotypes significantly (table 3). among the genotypes, the highest total sugar percent was in local-2 (5.63) followed by local-8, exotic-4 and bari sp-4 while the lowest sugar percent was in exotic-2 (2.06). higher total sugar producing genotypes were local-2, local-8, exotic-4 and bari sp-4. rest of the genotypes showed lower sugar content. starch content (%) starch content in leaves of nine genotypes varied from 13.48 36.42% with an average value of 23.92% (table 3). the maximum starch percent was in local-8 followed by local-1 and exotic-3. the lowest percent were in both exotic-4 and bari sp-4. according to usda (2009), starch content in leaves of sweet potato was 29.05%. crude fiber (%) crude fiber content in leaves varied significantly among the genotypes having the maximum percent in local-8 (17.79) followed by local-1 (15.76) and the lowest in bari sp-4 (11.16) (table 3). local-2, exotic-2 and bari sp-4 contained low crude fiber. the above results were higher than the report of uduro (2008). vitamin c (mg 100 g-1dry leaves) vitamin c content in dry leaves varied from 10.56 18.04 (table 3). the highest amount of vitamin c was in both local-8 and local-5 followed by exotic-4. the lowest amount was in local-2. higher vitamin c containing genotypes are local-8, local-5, local-1 and exotic-4. variation in vitamin c in leaves may be due to genetic or harvesting period as well as determining procedure. phenolic compounds (mg tae 100 g dry leaves-1) phenolic compounds acts as antioxidant. its presence in leaves was significantly varied among the genotypes (table 3). the maximum amount of phenolic compounds were in local-1 (385.0) followed by exotic-2. the lowest amount was in local-8 (226.20). greater amounts of phenolic compounds were in local1, exotic-2, bari sp-4, exotic-1 and local-2. islam et al. (2002) classified sweet potato genotypes with regard to the total phenolic compounds into low (<500 mg), medium (>700 mg) and high (>900 mg) as chlorogenic acid (ch a) equivalent 100g-1 of dry weight. he also stated that polyphenols concentrations exploring the potential of local and exotic sweet potato are organ-dependent and designated its order as leaves> petioles> stems >roots, indicating. ishiguro et al. (2004) added that sweet potato leaf contains high concentrations of polyphenols, when compared with the major commercial vegetables such as spinach, broccoli, cabbage and lettuce. tannins (polyethylene glycol equivalent mg 100g-1 dry leaves) the highest amount of tannins in leaves was in local-1 (157.70) followed by exotic-2, and the lowest amount was in exotic-4 (46.47) (table 3). local-1, exotic-2 and local-2 and had comparatively higher tannins over check variety bari sp-4. tannins content in leaves of the genotypes are very low status. tannins have both positive and negative effects on the human and animals. table 3. total sugar, starch, crude fiber, vitamin c, phenolic compounds and tannins in leaves of sweetpotato genotypes total sugar (%) starch (%) crude fibre (%) vitamin c (mg 100g-1 dry leaves) phenolic compounds (mg tae 100g-1) tannins (mg pege 100g-1 ) local-1 3.97 c 34.09 ab 15.76 bc 17.85 a 385.00 a 157.70 a local-2 5.63 a 24.19 c 13.74 d 10.56 e 291.60 d 89.13 c local-5 2.97 d 18.71 d 16.73 b 18.04 a 204.40 h 51.74 ef local-8 4.62 b 36.42 a 17.79 a 18.04 a 226.20 g 71.99 d exotic-1 2.60 d 17.61 d 15.38 c 12.15 cd 300.90 d 54.86 e exotic-2 2.06 e 26.46 c 14.73 cd 13.33 c 341.40 b 129.60 b exotic-3 3.75 c 30.71 b 15.07 c 11.18 de 266.70 e 48.63 ef exotic-4 4.51 b 13.48 e 15.68 c 15.68 b 255.50 f 46.47 f bari sp-4 4.70 b 13.61 e 11.16 e 12.55 c 316.50 c 82.90 c mean 3.87 23.92 15.12 14.376 287.59 81.44 % cv 4.40 6.11 2.78 3.65 1.53 3.90 tae = tannic acid equivalent, pege = polyethylene glycol equivalent, figures with dissimilar letters in a column differ significantly at dmrt0.01 leaf dry weight (g plant-1) leaf dry weight of sweet potato plant varied with genotypes (table 4). the highest leaf dry weight was in local-1 (35.22 g) followed by local-8. the lowest leaf dry weight was in exotic-3 (9.09 g). leaf dry weight of exotic-2 was 24.94 g followed by exotic-4 and local-2. rahman et al. (2015) recorded foliage dry weights of sweet potato from 6.13 to 10.57 g at 150 dap during summer and rainy season. iron (fe) iron content in leaves varied from 198.9 to 443.9 ppm (table 4). the highest amount was in local-5 followed by exotic-1 and exotic-3 whereas the lowest was in local-1 (198.9 ppm). local-5, exotic-3, exotic-1 had a comparatively higher amount of iron than the check bari sp-4. the above results partially agree with the report of usda (2009) where it ranged from 96 230 ppm. these variations are probably due to genotypic make-up as well as fertilizer application to the crop. table 4. leaf dry weight and minerals content in sweetpotato leaves genotypes leaf dry iron zinc calcium magnesium potassium phosphorus 50 hossain et al. weight (g plant-1) at 90 dap ppm % local-1 35.22 a 198.9 f 51.10 a 1.052 e 0.373 a 2.561 b 0.344 c local-2 21.21 d 269.5 e 42.45bc 1.088 de 0.384 a 2.688 a 0.343 c local-5 12.81 f 443.9 a 36.51 d 1.280 a 0.371 ab 2.569 b 0.361 bc local-8 30.30 b 274.6 e 32.98 e 1.082 de 0.312 c 2.645 a 0.392 ab exotic-1 17.88 e 339.6 b 45.06 b 1.058 e 0.309 c 2.561 b 0.432 a exotic-2 24.94 c 296.1 d 45.14 b 1.104 d 0.347 b 2.401 c 0.399 ab exotic-3 9.09 g 340.0 b 44.84 b 1.254 ab 0.389 a 2.361 c 0.388 ab exotic-4 21.33 d 293.2 d 39.71cd 1.153 c 0.296 c 2.717 a 0.409 a bari sp-4 17.08 e 319.6 c 28.30 f 1.221 b 0.240 d 2.383 c 0.334 c mean 21.10 308.36 40.7 1.144 0.335 2.542 0.378 cv (%) 5.54 1.89 3.43 1.11 2.68 1.33 4.01 bari sp-4 was check variety. figures with dissimilar letters in a column differ significantly at dmrt0.01 zinc (zn) zinc content was influenced by genotypes (table 4). the maximum zinc was in local-1(51.10 ppm) followed by local-2 (42.45 ppm). exotic-1, exotic-2 and exotic-3 had similar amount of zinc. the lowest amount was in bari sp-4 (28.30 ppm). local-1, exotic-1, exotic-2, exotic-3 and local-2 had higher amount of iron content. calcium (ca) calcium content in leaves varied significantly (table 4). the highest percentage was in local-5 (1.280) followed by exotic-3 and bari sp-4 whereas the lowest percentage was in exotic-1 (1.052) and exotic-1. local-5 and exotic-3 were performed better than bari sp-4. anita et al. (2006) recorded calcium 0.29%. these variations seem to be genotypic. magnesium (mg) the maximum magnesium percent was in local-2 (0.384) and local-1 (0.373) followed by local-5 (table 4). the lowest percentage was in bari sp-4 (0.240). magnesium content ranged from 0.240 to 0.384% with average value of 0.335%. local-2, local-1, local-5 and exotic-3 were rich in magnesium. the above result agrees with anita et al. (2006) . potassium (k) potassium content in leaves varied significantly (table 4). higher amount was in exotic-4 (2.717 %) which was similar to local-2 and local-8. the lowest amount of potassium was in exotic-3 (2.361 %). local-1, local-5 and exotic-1 contained a similar amount of potassium. the above results are more than that of usda (2009) where potassium was 0.48%. phosphorus (p) phosphorus content in leaves varied significantly (table 4). the highest amount of phosphorus (0.432%) was in exotic-4 followed by exotic-2, local-8 and exotic-3. the lowest phosphorus percent was in bari sp-4 (0.334). the higher phosphorus containing genotypes are exotic-4, exotic-2, local-8 and exotic-3. the above results are more than that of usda (2009) where it reported phosphorus of 0.054 %. it may be due to genetic makeup and phosphate fertilizer application to the crop. conclusion exploring the potential of local and exotic sweet potato the proximate analysis reveals that local-1, exotic-1, local-2 and local-8 are preferable genotypes. considering of total ash, crude fiber, vitamin c and phenolic compounds, local-1, exotic-2 and exotic-1 are performed better than check variety. similarly, local-5, exotic-1 and exotic-3 are preferable than check variety in respect to minerals content. tannin content in leaves of sweet potato were very low than the harmful limit. local-1 and local-8 were performed better than rest of the genotypes on account of organoleptic properties and dry matter yield of leaves. considering overall nutrient status, the studied genotypes may be ranked as local-1> exotic-2> exotic-1> local-5> bari sp-4> local-2> exotic3> local-8> exotic-4. it can be concluded that the leaves of local-1, local-5, local-8, exotic-1 and exotic-2 may be suitable for vegetables. acknowledgement the authors are owed to bangladesh university grants commission, dhaka-1207 and sylhet agricultural university research system, sylhet-3100 for funding to complete this research. references abbasi, k. s., t. masud, m. gulfraz, s. ali and m. imran. 2011. physico-chemical, functional and processing attributes of some sweet potato varieties grown in pakistan. african j. biotechnol. 10: 19570–19579. agbede, t. m. 2010. tillage and fertilizer effects on some soil properties, leaf nutrient concentrations, growth and sweet potato yield on an alfisol in southwest nigeria. soil tillage res. 110: 25–32. anita, b. s., e. j. akpan, p. a. okon, i. u. umoren. 2006. nutritive and antinutritive evaluation of sweet potato leaves. pak j. nutrit. 5(2): 166-168. aoac. 2012. association of analytical chemists’. official methods of aoac international, 19th ed., washington dc, usa. bdhs. 2014. bangladesh demographic health survey 2011. dhaka, bangladesh. national institute of population research and training, ministry of health and family welfare, dhaka, bangladesh. mitra and associates. bhuiyan, m.k.r., m.s. alam, a.t.m.t. islam, m. hossain and s.n. begum. 2008. production technology of newly released sweet potato varieties (in bangla), tuber crops research centre, bangladesh agricultural research institute (bari), gazipur-1701. 8p. dae. 2014. dept. of agricultural extension. annual report, 2013-14. sylhet, ministry of agriculture, people’s republic of bangladesh. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, bangladesh, dhaka-1215. 274p. fennema, r. o. and s. r. tannenabaum. 1996. introduction to food chemistry. in: fennema r o, karel m, sanderson g w, tannenabaum s r, walstra p, witaker j r (eds.). food chemistry, marel dkker inc., new york, usa, pp. 1-64. gichuhi, p. n., a. k. kpomblekou, a. c. bovell-benjamin. 2014. nutritional and physical properties of organic beauregard sweetpotato [ipomoea batatas (l.) lam] as influenced by broiler litter application rate. j. food sci. nutrit. 2: 332–340. huaman, z. 1992. systematic botany and morphology of the sweetpotato plant. technical information bulletin 25. international potato center, lima, peru. pp.22. 50 hossain et al. ishiguro, k, j. toyama, j. islam, m. yoshimoto, t. kumagai, y. kai, o. yamakawa. 2004. new sweetpotato cultivar for utilization in vegetable greens. acta horti. 637: 339­345. islam, s. 2014. nutritional and medicinal qualities of sweetpotato tops and leaves. cooperative extension program, university of arkansas, pine bluff, chicago, usa. islam, s. 2006. sweetpotato (ipomoea batatas l.) leaf: its potential effect on human health and nutrition. j. food sci. 71:13–21. islam, m. s., m. yoshimoto, s. yahara, s. okuno, k. ishiguro and o. yamakawa. 2002. identification and characterization of foliar polyphenolic compositions in sweetpotato (ipomoea batatas l.) genotypes. j. agric. food chem. 50: 3718–22. low, j. r., c. d. kapinga, c. loechl, j. lynam, and m. andrade. 2009. unleashing potential of in subsaharan affrica. in: challenge theme paper sweetpotato 3: nutritional fleshed sweetpotato (ofsp). social impact with orange sciences working paper, cip, peru, lima. makkar, h. p. s. 2003. quantification of tannins in tree and shrub foliage : a laboratory manual, kluwer academic publishers, po box 17, 3300 aa dordrecht, the netherlands. mccready, r. m., j. guggolz, v. siliviera and h. s. owens. 1950. anal. chem. 22: 1156. merril, a. l. and b. k. watt. 1973. energy value of foods... basis and derivation. human nutrition research branch, agricultural research service, u.s. dept. of agriculture, agriculture handbook. 34:11. law, n. h. 2002. carbohydrate analysis. in: introduction to chemical analysis of foods. s suzanne nielsen (editor). cbs publishers and distributors. newdelhi, india. oduro, i., w.o. elis and d. owusu. 2008. nutritional evaluation of two leafy vegetables: moringa olifera and ipomoea batatas leaves. sre. 3(2): 57-60. peterson, m. l. 2002. arsenic distribution in pore waters and sediments of puget sound lake, washington, the washington coast and seanich inlet, b c geochemical cosmochemica acta, 50: 353-369. rahman, h., a. f. m. s. islam, m. a. maleque tabassum r. 2015: morphophysiological evaluation of sweetpotato (ipomoea batatas l.) genotypes in acidic soil. asian j. crop sci. 7 267-276. ranganna, s. 1991. handbook of analysis and quality control for fruit and vegetable products. 2nd edition, tata mcgraw hill publishing company ltd., new delhi, india. 1112p. sadasivam, s., a. manickam. 1997. biochemical methods, 2nd edition, new age international (p) ltd., publishers and tamil nadu agril. uniersity, india. pp. 34-37, 256. singleton, v. l. and j. a. rossi. 1965. colorimetry of toal phenolics with phosphomolybdic phosphotungstic acid reagents. aemirican j. enol. viticult. 16: 144-158. usda. 2009. u.s. department of agriculture, agricultural research service. national nutrient database for standard reference, release 22. nutrient data laboratory home page, http://www.ars.usda.gov/ba/bhnrc/ndl, accessed 14 december 2009. woolfe, j.a. 1992. sweetpotato: an untapped food resource. cambridge university press, cambridge, uk. pp. 118-187. exploring the potential of local and exotic sweet potato yoshida, s, a. d. forno, j. a. cock, and k. a. gomez. 1976. physiological studies of rice. 2nd edition. international rice research inst. manila, philippines. bangladesh agron. j. 2018, 21(2): 87-95 effect of aqueous extract of sorghum crop residues on weed management and crop performance of wheat f. ahmed, m.r. uddin*, m.d. hossain, u.k. sarker, d. sarkar and d.n. chadny department of agronomy, bangladesh agricultural university, mymensingh-2202, bangladesh *corresponding author, email: romijagron@bau.edu.bd (received: 12 february 2019, accepted: 10 april 2019) keywords: wheat varieties, number of weeds, inhibition (%), yield and harvest index (%) abstract an experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh to evaluate the effect of aqueous extract of sorghum crop residues on weed management and crop performance of wheat. the experiment consisted of three varieties of wheat viz., bari gom-19, bari gom-21, bari gom-24 and five different levels of treatments such as no use of aqueous extract, aqueous extract of sorghum crop residues: 1:20 ratio (w/v), 1:30 ratio (w/v), 1:40 ratio (w/v) and hand weeding. the experiment was laid out in a randomized complete block design with three replications. seven weed species belonging to five families infested the experimental plots. weed population, weed dry weight and percent inhibition of weed were significantly influenced by aqueous extract of sorghum crop residues and varieties. the maximum weed growth was noticed with the variety bari gom-19 and the minimum was found in the variety bari gom-21. the grain yield as well as the other yield contributing characters produced by bari gom-21 was the highest among the studied varieties. the highest percent inhibition for all of the weeds was found in hand weeding treatment. the second highest percent weed inhibition was occurred in aqueous extract of sorghum crop residues @ 1:20 ratio (w/v) treatment which was 51.81, 51.10, 52.90, 55.58, 75.27, 73.83 and 53.85 percent for bathua (chenopodium album), mutha (cyperus rotundus), durba (cynodon dactylon), biskatali (polygonum hydropiper), angta (paspalum scrobiculatum), tit begun (solanum torvum) and shama (echinochloa crusgalli) respectively. the highest loss of grain yield was obtained where no aqueous extract of sorghum crop residues were used. the highest yield and yield attributes were observed where hand weeding is done followed by the application of aqueous extract of sorghum crop residues @1:20 ratio (w/v). wheat var. bari gom-21 with all treatments produced the highest grain and straw yield among the treatment combination. the results of this study indicate that different amount of aqueous extract of sorghum crop residues showed potential activity to suppress weed growth and it has significant effect on the yield of wheat. therefore, aqueous extract of sorghum crop residues might be used as an alternative way for weed management in effective and sustainable crop production. introduction wheat (triticum aestivum l.) is one of the world’s most commonly consumed cereal grains. in bangladesh, wheat is the second most important cereal crop next to rice. wheat yield in bangladesh has increased with the introduction of high yielding varieties and by the use of weed controlling measurements. in mailto:romijagron@bau.edu.bd 88 ahmed et al. 2015, average yield of wheat was estimated as 3.09 t ha-1 which was 1.75% higher than that of 2014 (bbs, 2015) but on an average grain yield is lower than many countries of the world. there are several reasons for yield losses in wheat but weed infestation is greater than the combined losses of insect pests and diseases and all other attributes. the traditional method of weed control is hand weeding which is very much laborious and time consuming. herbicide is effective in controlling weeds alone or in combination with hand weeding but it is harmful for the nature (ahmed et. al., 2005). beside this another observation was that "herbicides in combination with hand weeding would help to obtain higher crop yield but it efforts high cost of production" (prasad and rafy, 1995; sathyamoorthy et. al., 2004). with rising human health and ecological concerns about the adverse effects of indiscriminate use of farm chemicals research on alternative weed management methods is underway worldwide. exploitation of allelopathic potential of different crop/plant species for weed management under field conditions is one such approach. crop allelopathy controls weeds by the release of allele-chemicals from the living plants and/or through decomposition of phytotoxic plant residues (belz, 2004; khan et. al., 2005). sorghum [sorghum bicolor (l.) monech] is one of the strongest allelopathic crops which have been extensively used as a cover crop or through incorporation of its residue in soil to control weed. sorghum is a successful competitor against weeds in fields as empirically known. sorghum seems to have some inhibiting effects on the growth of weeds. these suggest the allelopathic potential of sorghum and it will be very useful for biological control of weeds. information regarding aqueous extract of sorghum crop residues for weed management is limited in our country. so, the study deserves to keep the significance in the current research interest in home and abroad about aqueous extract of sorghum crop residues having residual effects on weed control and yield performance to investigate the weed suppressing ability and to determine the optimum dose of aqueous extract of sorghum crop residues for the establishment of an easy, economic and sustainable method for efficient weed management and better yield of wheat. materials and methods the experiment was carried out at the agronomy field laboratory of bangladesh agricultural university, mymensingh from november 2016 to march 2017, located at 24°75' n latitude and 90°50' e longitude at an elevation of 18 m above the mean sea level characterized by non-calcareous dark grey floodplain soil belonging to the old brahmaputra floodplain, (aez-9). the soil of the experimental field was more or less neutral in reaction with ph value 6.8, low in organic matter and fertility level. the land type was medium high with silty loam in texture. the experiment consists of two factors including crop residues (5) i) no use of extract (control), ii) aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), iii) aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), iv) aqueous extract of sorghum crop residues @ 1:40 ratio (w/v) and v) hand weeding and wheat variety (3): i) bari gom-19 (sourav) ii) bari gom-21 (shatabdi) iii) bari gom-24 (prodip). the seeds were sown on 21 november, 2016 as per treatment specifications. the experiment was laid out in a randomized complete block design with three replications. thus total numbers of plots were 45. each plot size was (2 m2.5 m). the distance maintained between the individual plots was 0.5 m and the distance between the replication was 1.0 m. effect of aqueous extract of sorghum crop residues on weed 89 100 controlat weedof dry weight treatmentfrom weedof dry weight-controlat weedof dry weight × after collection, the crop residues were dried under shade in the covered threshing floor of agronomy field laboratory of bau. the studied crop residues were cut as small as possible by using sickle. the small pieces of sorghum crop residues were dipped into water for 24 hours and then collected the aqueous extract from residues. the prepared sorghum aqueous extract was applied two times (20 days and 40 days) after seed sowing by a hand sprayer and harvesting was done in 8th march, 2017. data were collected on the basis of different parameters of wheat and weeds. among them percent inhibition shows the suppressing ability of aqueous extract of sorghum residues on weed. inhibition (%) = data were also collected from wheat on yield basis such as grain yield, straw yield, harvest index etc which showed the yield performance of wheat. the recorded data were compiled and tabulated for statistical analysis. analysis of variance was done with the help of computer package, mstat-c program. the mean differences among the treatments were adjudged by duncan’s multiple range test. results and discussion infested weed species in the experimental field seven weed species belonging to five families infested the experimental field. local name, scientific name, family, morphological type and life cycle of the weed in the experimental plot have been presented in table 1. table 2. effect of variety on number and percent inhibition on different weeds number of weed per quadrate (25 x 25) cm2 % inhibition weed name bathua mutha biskatali durba tit begun shama angta bathua mutha biskatali durba tit begun shama angta variety v1 6.11 5.86 7.33b 6.13 0.80b 6.80a 1.00a 36.78c 40.06a 38.45b 39.40 47.51b 37.38 53.9 1b v2 5.86 5.53 7.53a 6.07 1.00a 6.26b 0.80b 38.97a 38.40b 39.62a 40.56 54.15a 39.29 58.1 9a v3 6.13 5.80 7.53a 6.27 1.00a 6.60ab 1.00a 37.80b 37.42b 38.49b 40.60 52.53a 38.09 54.2 5b sx� 0.10 0.12 0.05 0.08 0.02 0.13 0.03 0.27 0.36 0.33 0.38 1.31 0.89 0.72 cv (%) 6.72 6.88 2.67 5.16 5.70 7.87 9.32 2.81 3.57 3.29 3.66 9.80 8.94 5.01 v1 = bari gom-19 (sourav), v2 = bari gom-21 (shatabdi), v3 = bari gom-24 (prodip) effect of variety on number and percent inhibition on different weeds variety shows the significant effect on number of weed population for biskatali, tit begun, shama and angta and others are not significantly affected. the lowest number of weeds was found in different varieties for different weeds (table 2). on the other hand only shama and durba are not significant and rest of them are significantly affected in terms of percent inhibition. bathua (38.97), tit begun (54.15), biskatali (39.62) and angta (58.19) shows highest percent inhibition for v2 and mutha (40.06) is found in v1 variety. (table 2) table 1. infested weed species found growing in the experimental plots in wheat 90 ahmed et al. sl. no. local name scientific name family morphological type life cycle 1 mutha cyperus rotundus cyperaceae sedge perennial 2 durba cynodon dactylon poaceae grass perennial 3 bathua chenopodium album chenopodiaceae broad leaved annual 4 shama echinochloa crusgalli gramineae grass annual 5 angta paspalum scrobiculatum gramineae grass annual 6 tit begun solanum torvum solanaceae broad leaved perennial 7 biskatali polygonum hydropiper polygonaceae broad leaved annual effect of aqueous extract of sorghum on number and percent inhibition on different weeds numbers of weed populations are significantly affected by the treatments for all weed species. lowest weed population was found in c4 treatments (hand weeding) followed by c1 treatment (table 3). highest percent inhibition was also found in c4 treatment which is followed by c1 treatment where the concentration of aqueous extract of sorghum was high (1:20). numerically 51.81, 51.10, 55.58, 52.90, 73.83, 53.85 and 75.26 percent inhibition were found in bathua, mutha, biskatali, durba, tit begun, shama and angta respectively for c1 treatment. (table 3) table 3. effect of aqueous extract of sorghum on number and percent inhibition on different weeds number of weed per quadrate (25 × 25) cm2 % inhibition weed name bathua mutha biskatali durba tit begun shama angta bathua mutha biskatali durba tit begun shama angta treatments co 8.78a 8.33a 11.00a 8.77a 1.99a 9.55a 2.00a 0.00e 0.00e 0.00e 0.00e 0.00e 0.00e 0.00e c1 5.11d 4.66d 6.44c 5.66d 0.67c 5.33d 0.55d 51.81b 51.10b 55.58b 52.90b 73.83b 53.85b 75.26b c2 6.66 c 5.99c 7.66b 6.44c 0.67c 7.33c 0.89c 35.56c 41.11c 40.50c 40.20c 56.12c 38.26c 62.73c c3 7.55b 7.55b 7.66b 7.22b 1.22b 8.00b 1.22b 23.32d 22.67d 31.96d 30.48d 32.54d 24.42d 39.25d c4 2.07 e 2.11e 4.55d 2.66e 0.11d 2.55e 0.00e 78.57a 78.19a 66.21a 77.32a 94.48a 76.01a 100.0a sx� 0.13 0.13 0.07 0.11 0.02 0.17 0.03 0.35 0.46 0.43 0.49 1.68 1.14 0.93 cv (%) 6.72 6.88 2.67 5.16 5.70 7.87 9.32 2.81 3.57 3.29 3.66 9.80 8.94 5.01 in a column, figures with the same letter do not differ significantly as per dmrt. c0 = no use of extract, c1 = aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), c2 = aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), c3 = aqueous extract of sorghum crop residues @ 1:40 ratio (w/v), c4 = hand weeding combined effect of variety and aqueous extract of sorghum on number and percent inhibition on different weeds for all the weed species v2c4 combination was found the lowest number of weed population. on the other hand highest percent inhibition was also found in the same combination. (table 4) table 4. combined effect of variety and aqueous extract of sorghum on number and percent inhibition on different weeds effect of aqueous extract of sorghum crop residues on weed 91 number of weed per quadrate (25 × 25) cm2 % inhibition weed name bathua mutha biskatali durba tit begun shama angta bathua mutha biskatali durba tit begun shama angta treatments v1c0 8.66ab 8.00abc 11.00b 8.33b 1.33b 10.33 2.00a 0.00 0.00g 0.00f 0.00h 0.00 0.00 0.00g v1c1 4.66g 4.667f 6.66g 6.33e 0.67d 5.33 0.67d 50.13 51.49b 54.61c 51.40d 71.85 53.09 72.43c v1c2 7.33d 6.66d 6.67g 6.33e 0.67d 7.33 1.00c 34.16 45.79c 40.23d 40.45ef 50.32 37.77 60.32d v1c3 7.66cd 7.66bc 8.00 e 7.00cd 1.00c 8.33 1.33b 23.08 25.68e 32.10e 30.13g 31.93 22.65 36.78f v1c4 2.23h 2.33g 4.33j 2.66gh 0.33e 2.66 0.00f 76.54 77.31a 65.32b 74.91b 83.44 74.66 100.0a v2c0 8.33bc 8.33ab 11.67a 9.00a 2.33a 9.00 2.00a 0.00 0.00g 0.00f 0.00h 0.00 0.00 0.00g v2c1 5.00fg 4.67f 6.67g 5.33f 0.67d 5.33 0.33e 53.29 51.76b 56.58c 55.14c 75.04 55.18 80.52b v2c2 6.33e 5.33f 7.67ef 6.33e 0.67d 7.00 0.67d 37.18 39.81d 40.62d 38.39f 60.30 39.05 64.17d v2c3 7.66cd 7.33c 7.67ef 7.33c 1.33b 7.66 1.00c 23.68 21.20f 31.44e 29.47g 35.41 25.75 46.26e v2c4 2.00h 2.00g 4.00j 2.33h 0.00f 2.33 0.00f 80.72 79.20a 69.44a 79.78a 100.0 77.84 100.0a v3c0 9.33a 8.66a 10.33c 9.00a 2.33a 9.33 2.00a 0.00 0.00g 0.00f 0.00h 0.00 0.00 0.00g v3c1 5.66ef 4.66f 6.00h 5.33f 0.67d 5.33 0.67d 52.01 50.19b 55.56c 52.07d 74.61 53.28 72.83c v3c2 6.33e 6.00e 8.66d 6.66de 0.67d 7.66 1.00c 35.33 37.74d 40.66d 41.80e 57.75 37.97 63.71d v3c3 7.33d 7.66bc 7.33f 7.33c 1.33b 8.00 1.33b 23.21 21.09f 32.35e 31.83g 30.29 24.85 34.72f v3c4 2.00h 2.00g 5.33i 3.00g 0.00f 2.66 0.00f 78.45 78.06a 63.88b 77.28b 100.0 75.53 100.0a sx̅ 0.25 0.29 0.12 0.18 0.03 0.29 0.05 0.61 0.79 0.74 0.85 2.90 1.99 1.60 cv (%) 6.72 6.88 2.67 5.16 5.70 7.87 9.32 2.81 3.57 3.29 3.66 9.80 8.94 5.01 in a column, figures with the same letter do not differ significantly as per dmrt. v1 = bari gom-19 (sourav), v2 = bari gom-21 (shatabdi), v3 = bari gom-24 (prodip) c0 = no use of extract, c1 = aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), c2 = aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), c3 = aqueous extract of sorghum crop residues @ 1:40 ratio (w/v), c4 = hand weeding effect of variety on yield and yield contributing characters of wheat varietal effect on yield and yield contributing characters of wheat showed the significant effect. highest plant height, higher number of total tillers and effective tillers hill-1, higher number of grain spike-1, higher number of filled grain spike-1, highest straw yield and highest harvest index was found in v2 (bari gom-21) variety (table 5).the highest grain yield (3.84 t ha-1) was obtained in bari gom-21 followed by bari gom-24 (3.69 t ha-1). (fig. 1) table 5. effect of variety on yield and yield contributing characters of wheat varieties plant height (cm) no. of total tillers hill–1 no. of effective tillers hill–1 panicle length (cm) no. of grains spike-1 filled grain spike–1 1000 grain weight (gm) straw yield (t ha–1) harvest index (%) v1 88.71c 4.02b 3.16b 10.29 42.23 15.22b 55.18a 4.01b 45.14b v2 95.51a 4.13a 3.35a 10.46 43.36 15.75a 53.60ab 4.36a 46.75a v3 91.24b 4.07ab 3.25b 10.36 42.76 15.42ab 52.39b 4.35a 45.57b sx� 0.761 0.023 0.032 0.105 0.385 0.141 0.606 0.037 0.348 cv (%) 3.21 2.14 3.85 3.92 3.48 3.53 4.37 3.40 2.94 in a column, figures with the same letter do not differ significantly as per dmrt. v1 = bari gom-19 (sourav), v2 = bari gom-21 (shatabdi), v3= bari gom-24 (prodip) 92 ahmed et al. fig. 1. grain yield as influenced by variety (bar represents standard error mean) here, v1 = bari gom-19 (sourav), v2 = bari gom-21 (shatabdi), v3 = bari gom-24 (prodip) effect of aqueous extract of sorghum crop residues on yield and yield contributing characters of wheat aqueous extract of sorghum crop residues had also significant effect on yield and yield contributing characters. the highest grain yield (3.97 t ha-1) was produced by c4 treatment, followed by c1 (3.88 t ha -1) and lowest one (2.61 t ha-1) was produced by c0 (no use of extract) treatment due to the production of higher number of effective tillers hill-1, higher number of grain spike-1, higher number of filled grain spike-1. the lowest grain yield was produced in c0 treatment. (table 6 and fig. 2). uddin and pyon (2010) also reported the similar results, where crop residues influenced in crop performance. table 6. effect of aqueous extract of sorghum crop residues on yield and yield contributing characters of wheat residues plant height (cm) no. of total tillers hill–1 no. of effective tillers hill–1 panicle length (cm) no. of grains spike-1 filled grain spike–1 1000 grain weight (gm) straw yield (t ha–1) harvest index (%) c0 82.27d 3.46d 2.70e 9.57c 39.72d 13.28d 51.27b 3.51c 42.12b c1 94.92b 4.21b 3.41b 10.58ab 44.08b 16.24b 53.27b 4.29b 47.48a c2 92.75bc 4.13b 3.29c 10.49b 42.62c 15.42c 53.44b 4.40ab 46.60a c3 91.02c 4.02c 3.13d 10.28b 41.02d 15.05c 52.96b 4.43ab 46.23a c4 98.14a 4.54a 3.72a 10.92a 46.54a 17.34a 57.66a 4.54a 46.67a sx� 0.983 0.030 0.042 0.135 0.497 0.182 0.782 0.048 0.450 level of significance ** ** ** ** ** ** ** ** ** cv (%) 3.21 2.14 3.85 3.92 3.48 3.53 4.37 3.40 2.94 ** =significant at 1% level of probability. c0 = no use of extract, c1 = aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), c2 = aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), c3 = aqueous extract of sorghum crop residues @ 1:40 ratio (w/v), c4 = hand weeding. 0 1 2 3 4 5 v1 v2 v3 variety gr ain yi eld (t h a–1 ) effect of aqueous extract of sorghum crop residues on weed 93 fig. 2. grain yield as influenced by aqueous extract of sorghum crop residues (bar represents standard error mean) c0 = no use of extract, c1 = aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), c2 = aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), c3 = aqueous extract of sorghum crop residues @ 1:40 ratio (w/v), c4 = hand weeding combined effects of variety and aqueous extract of sorghum crop residues on yield and yield contributing characters of wheat yield and yield contributing characters like straw yield and grain yield were significantly affected by the interaction between variety and crop residues. v2c4 combination showed the maximum result which was followed by v3c1. (table 7) table 7. combined effects of variety and aqueous extract of sorghum crop residues on yield and yield contributing characters of wheat variety x residues plant height (cm) no. of total tillers hill–1 no. of effective tillers hill–1 spike length (cm) no. of grain spike-1 no of spikelet spike–1 1000 grain weight (gm) grain yield (t ha–1) straw yield (t ha–1) harvest index (%) v1c0 80.73 3.40 2.57 9.55 39.26 12.94 55.07 2.16i 3.11g 41.00 v1c1 90.73 4.13 3.33 10.48 43.64 16.10 53.12 3.63ef 4.24cde 46.10 v1c2 89.87 4.10 3.20 10.41 42.11 15.33 55.90 3.59f 4.16de 46.34 v1c3 88.70 4.03 3.05 10.22 40.46 14.67 55.73 3.52f 4.15de 45.92 v1c4 93.53 4.43 3.63 10.81 45.67 17.05 56.07 3.77de 4.36bcd 46.35 v2c0 83.72 3.45 2.83 9.59 40.04 13.78 49.56 2.95g 3.82f 43.46 v2c1 99.69 4.27 3.53 10.72 44.86 16.47 53.54 4.08ab 4.09e 46.88 v2c2 96.49 4.17 3.40 10.59 42.95 15.51 52.87 4.03abc 4.57ab 46.86 v2c3 94.03 4.00 3.17 10.35 41.45 15.40 52.18 4.02abc 4.61ab 46.58 v2c4 104.48 4.67 3.80 11.04 47.47 17.60 59.83 4.13a 4.69a 46.84 v3c0 82.37 3.43 2.70 9.57 39.85 13.23 49.19 2.73h 3.59f 41.22 v3c1 94.40 4.23 3.37 10.56 43.74 16.23 53.15 3.95bc 4.56ab 46.40 v3c2 91.90 4.13 3.27 10.47 42.81 15.41 51.55 3.90bcd 4.48abc 46.58 v3c3 90.33 4.03 3.20 10.26 41.14 15.08 50.95 3.88cd 4.52ab 46.22 v3c4 97.20 4.53 3.73 10.95 46.29 17.30 57.09 4.02abc 4.57ab 46.82 sx� 1.70 0.050 0.072 0.234 0.861 0.315 1.35 0.055 0.084 0.779 level of significance ns ns ns ns ns ns ns * ** ns cv (%) 3.21 2.14 3.85 3.92 3.48 3.53 4.37 2.61 3.40 2.94 ** =significant at 1% level of probability, * =significant at 5% level of probability, ns = non significant 0 1 2 3 4 5 c0 c1 c2 c3 c4 crop residues gr ain yi eld (t h a–1 ) 94 ahmed et al. v1 = bari gom-19 (sourav), v2 = bari gom-21 (shatabdi), v3 = bari gom-24 (prodip) c0 = no use of extract, c1 = aqueous extract of sorghum crop residues @ 1:20 ratio (w/v), c2 = aqueous extract of sorghum crop residues @ 1:30 ratio (w/v), c3 = aqueous extract of sorghum crop residues @ 1:40 ratio (w/v), c4 = hand weeding conclusion from the above results it was found that the wheat var. bari gom-21 with c4 (hand weeding) treatment exhibited the superior effect and bari gom-21 with c1 showed quite close result with it. results of the present study reveal that application of aqueous extract of sorghum crop residues has positive effect on yield for most of the studied traits. it also shows that aqueous extract of sorghum crop residues have herbicidal activity for suppressing weed growth and there is immense prospect of sorghum crop residues as a weed management tool. therefore, aqueous extract of sorghum crop residues could be a prospective source of weed control tool for crop production in modern agricultural science which minimizes cost of production, environmental pollution, unsafe agricultural production, human health concerns, soil sickness and depletion of crop diversity. references ahmed, g.j.u., m.k.a. bhuiyan, c.r. riches, m. mortimer and d. jhonson 2005. farmer’s participatory studies of integrated weed management system for intensified lowland. proceeding of the 8th biennial agronomy convention. bangladesh agron. j. 31-32. bbs (bangladesh bureau of statistics) 2015. statistical year book of bangladesh. bangladesh bureau, statistics division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. pp. 78-79. belz, r.g. 2004. evaluation of allelopathic traits in triticum spp l. and secale cereal l.phd thesis, university of hohenheim, stuttgart, germany. khan, t.d., m.i. chung, t.d. xuan and s. tawata 2005. the exploitation of crop allelopathy in sustainable agricultural production. j. agron. crop sci. 191: 172-184. prasad, k. and a. rafey 1995. effect of integrated weed management on weed growth, nutrient uptake, economics and energetics in rainfed upland rice (oryza sativa). indian j. agr. sci. 65: 260-264. sathyamoorthy, n.k., s. mahendran, r. babu and t. ragavan 2004. effect of integrated weed management practices on total weed dry weight, nutrient removal of weeds in rice-rice wet seedbed system. j. agron. 3: 263-267. uddin, m.r. and j.y. pyon 2010. herbicidal activity of rotation crop residues on weeds and selectivity to crops. j. agril. sci. 37: 1-6. bangladesh agron. j. 2019, 22 (1): 15-25 response of soil applied herbicides at different application timings on the weed control efficacy and phytotoxicity to rice in dry-seeded condition sharif ahmed1*, akbar hossain2, abu abdullah miajy3 and tahir h. awan4 a international rice research institute, bangladesh office, b bangladesh wheat and maize research institute, nashipur, dinajpur-5200, c rice research institute, kala shah kaku, punjab, pakistan *corresponding e-mail: s.ahmed@irri.org (received: 18 march 2019, accepted: 20 august 2019) keywords: oxadiargyl, pendimethalin, pre-emergence herbicide, soil moisture, phytotoxicity abstract dry-seeded rice (dsr) is a labor and water saving emerging production system. the use of pre-emergence herbicides was found to be the most effective weeds control measure under the dsr system. although several herbicides are now available in market, the selection of right herbicides with a time of application is crucial for effective control of weeds as well as to reduce the phyto toxicity of crops. a field study in a split-plot design with three replications was conducted to evaluate the effect of application time of soil applied herbicides (viz., 3 times before crop sowing, after crop sowing but before the first irrigation, and after sowing and first irrigation) and four weeding regimes (viz., weed free, partialweedy, herbicide oxadiargyl 80 g ai ha-1, and pendimethalin 1000 g ai ha-1) on weed control efficacy, crop performance as well as phytotoxicity of applied herbicides under dsr system. rice plant stand establishment was highly influenced by application time of herbicides and weeding regimes. application of pendimethalin at 1000 g ai ha-1 significantly reduced the density of rice plant, more so as sowing was advanced. compared with the non-treated (partial-weedy) treatment (190 to 195 rice plants m-2), pendimethalin application before sowing, after sowing but before irrigation, and after sowing and irrigation reduced rice plant density by 48, 25 and 12%, respectively. while no significant difference was observed on plant density due to the application of oxadiargyl 80 g ai ha-1, regardless of application time. in case of weed control efficacy for individual herbicides, pendimethalin effectively controlled weeds even spraying before sowing and irrigation; but comparatively less effective than spraying after irrigation. in controlling weeds, oxadiargyl was only effective when spraying after sowing and irrigation, but not before irrigation. grain yield was significantly increased as the time of herbicide was delayed from before sowing (2.2-2.4 t ha-1), after sowing but before irrigation (2.5-2.6 t ha-1), and after sowing and irrigation (4.0-4.1 tha-1). the results suggest that pre-emergence herbicides should be applied after sowing and irrigation for controlling weeds effectively and also reduce crop toxicity under the dsr system. introduction due to the decreasing availability of labor and water, farmers in many asian countries are shifting their traditional puddled transplanted rice cultivation system to dry seeded rice (dsr) system (ahmed et al., 2014; kumar and ladha, 2011). dsr can be established directly in the field with no prior tillage (zero tillage) or following dry tillage. dry seeding reduces labor requirement by eliminating seedling rearing in nursery beds, seedling uprooting, repeated tillage under the about:blank 24 ahmed et al. wet condition to puddle the soil and manual transplanting (bari and ahmed, 2018). dry-seeding readily enables mechanization of rice establishment using a ‘power tiller operated seeder’ (ptos) powered by a two-wheel tractor, or using 4-wheel tractor mounted seed drills, with low labor requirement (riches et al., 2008). dry seeding also reduces irrigation water requirement through the exclusion of puddling. although the dsr system has many benefits over puddled transplanted rice, however weeds are major constraints to its success when grown under non-ponded conditions (ahmed and chauhan, 2014; singh et al., 2006). in the dsr system, weeds and rice germinate simultaneously and most often weeds show more vigorous growth than rice; as a result, the rice seedlings are suppressed by weeds at an early growth stage (chauhan and johnson, 2011). in asian countries, manual weeding is very common but because of increasing labor scarcity and labor price, manual weeding alone is not an option. in addition, at the early vegetative growth stage, the morphological characters of rice seedlings and some weeds (particularly grasses) are similar, as a result, manual weeding is difficult at the initial stage of weeds (ahmed et al., 2015; rahman et al., 2012). the use of herbicides were found to be the most effective weeds control measures under dsr system (ahmed and chauhan, 2014; ahmed et al., 2015; rahman et al., 2012; singh et al., 2006). herbicides can be applied as a pre-emergence (soil applied to control weeds before emergence) spray and/or a post emergence (control weed after emergence) spray. however, the pre-emergence herbicide is essential to manage weeds effectively in dsr (khaliq et al., 2011; singh et al., 2007). the weed control efficiency of preemergence herbicide and their phytotoxicity depend on several factors such as soil moisture, soil tilth, environmental conditions, weed species, and herbicide doses (ahmed and chauhan, 2015; awan et al., 2016). dhareesank et al. (2006) and levene and owen (1995) noticed that soil moisture is important during the time of herbicide (s) application, which influences both weed control efficacy and crop phytotoxicity by influencing the herbicide absorption, translocation, or metabolism. moisture may help to increase the efficacy of preemergence herbicide by moving the herbicide into the soil which reduces the loss of the herbicide from the soil surface, and absorption of herbicide by the emerging seedlings (si et al., 2009). chauhan and johnson (2011) reported that the pre-emergence herbicide oxadiazon at 1.0 kg ha-1 reduced rice shoot biomass by 22 to 36% under dry soil conditions, while by 43 to 56% in saturated conditions. herbicides are sprayed by manually using backpack knapsack sprayer. but manually spray is labor consuming and mentioned earlier that labor scarcity is increasing and assumed that in future labor will be more problem. for these reasons, it is important to explore some mechanization options for pre-emergence herbicide spray in the dsr system. therefore, the aim of the study was to determine the effect of time of application of soil applied herbicide on rice plant establishment, weed growth and crop yield in dry-seeded rice. materials and methods the field experiment was conducted at the research farm of the regional agricultural research station (rars) of bangladesh agricultural research institute (bari), jessore (23°11' n, 89°14' e and 16 m above mean sea level) in the boro (dry) season of 2012-13. the area belongs to the aez-11, of high ganges river floodplain. the climate of the area is subtropical, with an average annual rainfall of 1590 mm (90% of which is received during may to september), minimum temperature of 6–9 0c in january, and maximum temperature of 36– 440 c in april and may. the soil at 0–15-cm depth was a clay loam, with a response of soil applied herbicides 17 bulk density of 1.56 mg m3, a ph of 7.8, organic carbon of 1%, sand of 32%, silt of 31%, and clay of 37%. there experiment was arranged in a split-plot design with three replications. main plots were assigned with time of herbicides application: (i) before sowing (bs) herbicide was applied after land leveling and one day before sowing; (ii) after sowing but before irrigation (asbi) (irrigation was applied shortly after sowing, on the same day); (iii) after sowing and irrigation (asi) herbicide was applied two days after irrigation; where sub-plots were arranged with weeding regimes (i) weed-free; (ii) partial weedy; (iii) oxadiargyl 80 g active ingredient (ai) ha-1 (iv) pendimethalin 1000 g ai ha-1. size of the sub-plot size was 13.5 m2 (4.5 m x 3 m). all herbicides were applied using a knapsack-sprayer with a 1.2 m boom with three flat fan nozzles and spray volume was 450 l ha -1. to prevent the movement of herbicide after irrigation, the plots were separated by bunds and irrigated one plot at a time. in the weed-free treatment, weeds were removed by manual-hand weeding (at 10, 25, 35, 50 and 65 das) in five times. in the partial-weedy treatment, one hand weeding was performed at 40 das and weeds were allowed to grow before and after the hand weeding. one weeding was applied as in the absence of any weed control; there may be no or very little yield of dsr (chauhan and johnson, 2011). in addition, it is rare that farmers leave their rice fields infested with weeds throughout the season in irrigated areas. dry seed of the rice var. brri dhan28 (life span 140 days) was sown on 1 february 2013 at 40 kg seed ha-1 and a row spacing of 20 cm. the crop was sown into dry tilled soil using a seed-drill with a fluted roller seed-metering device and a power tiller linked to a 2-wheel tractor. fertilizer was applied at 160-2060-12-2.2 kg ha-1 of n-p-k-s-zn, respectively (brri, 2011), in the forms of urea, triple superphosphate (tsp), mop, gypsum, and zinc sulphate, respectively. except for urea, other fertilizers were broadcast during final land preparation (prior to sowing). the urea was applied in four equal splits: at 14 das, tillering initiation stage (35das), maximum tillering (55 das), and panicle initiation stage (65 das). a light irrigation was done just after sowing and the field was kept saturated up to 20 das and then irrigations were given based on soil water tension using a threshold value of 15 kpa at 15 cm soil depth (sudhir-yadav et al., 2011). at each irrigation, water was added until the depth of water on the soil surface reached 5cm. data on the density of rice plant (no. m-2) was determined at 14 das by counting the number of plants in 1 m of row length in five randomly selected locations in each plot. weed density was determined at 20 das, and weed density and weed biomass were determined at 40 das and at anthesis; separated into grasses, broad leaf,and sedges. total weeds biomass was also determined at the time of rice harvest. at each sampling time, all weeds were collected from two randomly located quadrats of 40 cm ×x 40 cm. the biomass was measured after oven drying the samples at 70 0c for 72 h. at harvest, panicle density (no. m-2) was determined by counting the number of panicles in 1 m row lengths at 4 randomly selected spots in each plot. rice grain yield was determined from an area of 6.6 m2. grain yield was converted to tha−1 at 14% moisture content. regression analysis between weed biomass and rice grain yield was done using software sigma plot11.0 (systat software, inc., point richmond, ca). all crop and weed data were analyzed anova to evaluate differences between treatments and the means were separated using the least significant differences (lsd) at the 5% level of significance using statistical software crop stat 7.2. 24 ahmed et al. results and discussion plant density of rice was ranged from 101 to 195 plant m-2 and varied significantly (p≤ 0.01) by both application time of herbicides and weeding regimes (figure 1). plant density ranged from 101 to 195 plant m-2. the lower plant density was recorded in pendimethalin treated plots and considered with the application time; while plant density decreased significantly when application time was advanced. for example, compared with the non-treated plots (190 to 195 rice plants m-2), plant density decreased by 48, 25 and 12% when pendimethalin application time was before sowing, after sowing but before irrigation, and after sowing and irrigation, respectively. in contrast, oxadiargyl did not affect plant density; irrespective of application time. adequate and uniform plant density is pre-requisites to achieving optimum yield in dry-seeded rice (ahmed et al., 2014; chauhan and opeña, 2012). in the study, the application of pendimethalin to dry soil before irrigation had more phytotoxicity than applied after irrigation. fig. 1. effect of application time of soil applied herbicides and weeding regimes on rice plant stand establishment density at 14 das in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction lsd at 5% level of significance. these results are consistent with the findings of jordan et al. (1998) who suggested that pendimethalin should be applied once the rice seed has imbibed water but prior to the emergence of both rice and weeds. the results also supported by the previous study in where they found, compared with the nontreated treatment, plant density decreased by 14 to 22% when rain was occurred immediate after application of pendimethalin; however, in the same study plant density was similar between pendimethalin treated and non-treated plots when there was no rain immediate after sowing (ahmed and chauhan, 2014). similar results were reported by chauhan and opeña (2012), who found that rice plant stand was lower compared with the non-treated plots when heavy rains occurred immediately after the oxadiazon application. thus, soil moisture at the time of application has an important influence on herbicide phytotoxicity in rice.the dominant weed species in the experiment were: celosia argentea l., cyperus rotundus l., dactyloctenium aegyptium (l.) willd., digitaria ciliaris (retz.) koel., echinochloa colona (l.) link., eleusine indica (l.) gaertn, leptochloa chinensis response of soil applied herbicides 19 l., phyllanthus niruri l., and spilanthes paniculata wall. ex dc. at 20 das, there was a significant interaction between herbicide timing and weeding regimes on the density of grass and broad leaf weeds, but not for sedges (figure 2). pendimethalin was found very effective against grasses regardless of application time and reducing the density of grass species to zero when applied before sowing or after sowing but before irrigation, and reducing it to 8% in the weedy plots when applied after sowing. oxadiargyl was also found effective against grasses when applied at after sowing, but before and after irrigation (grass density was reduced 80 and 88%, respectively, in comparison with the weedy treatment). but the performance of oxadiargyl was very poor when applied before sowing and reduced the grass density by only 38%. the increase of broadleaf weed, oxadiargyl was not effective when applied before sowing; however, it effective and reduced density by 32 and 77% when applied after sowing but before irrigation, and after sowing and irrigation, compared with the non-treated plots (330-360 plant m-2). regarding the application time, pendimethalin controlled broadleaf more effectively than oxadiargyl when applied before sowing, and after sowing but before irrigation; however, applied after sowing and irrigation, oxadiargyl was more effective than the pendimethalin. fig. 2. effect of application time of soil applied herbicides and weeding regimes on grasses, broadleaf and sedge weed density at 20 das in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction lsd at 5% level of significance. compared with the non-treated plots, pendimethalin reduced broadleaf density by 29, 56, and 63% when applied before sowing, after sowing but before irrigation, 24 ahmed et al. and after sowing and irrigation, respectively. the effectiveness was greatest for both herbicides when applied after sowing and irrigation. neither herbicide was able to control sedge. pendimethalin effectively controlled grass weeds, but the poor control of sedge weeds was consistent with previous studies (ahmed and chauhan, 2014; khaliq et al., 2011; singh et al., 2006). on the other hand, oxadiargyl is a very effective pre-emergence herbicide, used to control a range of grass, broadleaved, and sedge weeds in different crops (dickmann et al., 1997; gitsopoulos and froud-williams, 2004). the interactions between application time and weeding regimes on total weed density and weed biomass recorded at 40 das (before hand weeding in partial-weedy plots) were found significant (p≤ 0.01) (figure 3). considered with the weeding regimes, partial-weedy plots had always higher weed density (498 to 557 plants m-2) and biomass (44 to 48 g m-2) than the herbicides treated plots. between the herbicides, oxadiargyl performed better than the pendimethalin when applied after sowing and irrigation and compared with the non-treated plots oxadiargyl reduced weed density and biomass by 57 and 41%, respectively, in where pendimethalin did 46 and 37%. although pendimethalin application before sowing, and after sowing but before irrigation had similarly reduced weed density and biomass, compared with the non-treated plots; however, oxdiargyl was not effective in at that application. compared with the non-treated plots, oxdiargyl reduced weed density and biomass by 6 and 40%, and 11 and 20% when applied before sowing, and after sowing, but before irrigation, respectively. at anthesis, weed density and biomass had similar trends to the density and biomass at 40 das (figure 4). at this stage, both of the herbicides had more effective weed control when applied after sowing and irrigation, and compared with the partial-weedy plots; where oxadiargyl reduced weed density and biomass by 43 and 44% and pendimethalin reduced 38 and 40%, respectively. fig. 3. effect of application time of soil applied herbicides and weeding regimes on weed density and biomass at 40 das in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction lsd at 5% level of significance. response of soil applied herbicides 21 fig. 4. effect of application time of soil applied herbicides and weeding regimes on weed density and biomass at rice anthesis in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction lsd at 5% level of significance. the results of weed density and biomass indicate that the application of pendimethalin before sowing had a significant effect on weed density and weed biomass, while oxadiargyl did not response. there was a consistent trend for better herbicide performance with the application after sowing and irrigation than before irrigation. the result was that weed density and biomass of oxadiargyl and pendimethalin applied after sowing and irrigation were similar. these results were consistent with the findings of ahmed and chauhan (2015), who reported that both of the herbicides (oxadiargyl and pendimethalin) were similarly performed in terms of controlling weeds when they applied after sowing and irrigation. panicle density was strongly affected by both application time and weeding regimes (figure 5). the highest numbers of panicles (320 to 335 m-2) were recorded in the weed-free plots, while plots treated with herbicides had always lower numbers of panicle as compared with the weed-free plots. regarding the application time, all herbicides significantly (p≤ 0.01) reduced panicle density when application time was advanced. the effect of oxidargyl and pendimethalin on panicle density was similar within each application time. the mean reduction in panicle density was 50, 40 and 12% with the application before sowing, after sowing but before irrigation, and after sowing and irrigation, respectively, compared with the weedfree plots. the lowest panicles (160 to171 m-2) were recorded in the partialweedy plots. 24 ahmed et al. fig. 5. effect of application time of soil applied herbicides and weeding regimes on rice panicle density m-2 at physiological maturity in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction (lsd at 5% level of significance. trends in the effects of the treatments on grain yield were similar to the effects on panicle density, with higher yield as the time of herbicide application was delayed (figure 6). regarding the application time, grain yield of rice in oxidiargyl and pendimethalin treated plots were found significantly similar and the highest (oxadiargyl 4.10 t ha-1 and pendimethalin 3.97 t ha-1) when applied at after sowing and after irrigation. fig. 6. effect of application time of soil applied herbicides and weeding regimes on rice grain yield in dry seeded boro rice. bs represents herbicide application before sowing; asbi represents herbicide application after sowing but before irrigation; asi represents herbicide application after sowing and irrigation. the vertical bar indicates interaction lsd at 5% level of significance. however, the maximum grain yield obtained in herbicides treatments had 1 t ha-1 lower yield than the yield of weed-free treatment (4.90 to 5.05 t ha-1). partialweedy treatment had always lower yield (1.90 to 2.07 t ha-1) and herbicide application after sowing and irrigation increased yield by 2.1 t ha-1, compared response of soil applied herbicides 23 with the partial-weedy treatment. however, rice grain yield was negatively correlated with weed biomass at harvest and 73% (r2 = 0.73) of the variation was explained by this relationship (figure 7). these results were similar to the previous studies in bangladesh and the philippines and both of which found that grain yield was negatively correlated with weed biomass (ahmed and chauhan, 2014; chauhan and opeña, 2012). fig. 7. relationship between rice grain yield and weed biomass at harvest in dry seeded boro rice. conclusion most of the soil applied herbicides are required sufficient soil moisture which is usually provided by irrigation or rainfall. the moisture turns the herbicide into a solution that helps absorb or adsorb by weed seeds or uptake by emergence weeds. the current study suggested that to increase herbicide efficacy on weeds and reduce phytotoxicity to dry seeded rice, both oxadiargyl and pendimethalin should be applied after sowing and irrigation. in addition, the study also suggested, pre-plant application of pendimethalin might not be feasible, and this might reduce some mechanization options (e.g., spray with a tractor before irrigation/wet conditions). the results also indicated that there is a need to further strengthen weed management strategies as the yield gap was around 1 t ha-1 between the weed free treatment and treatment with pre-emergence herbicide followed by one hand weeding. acknowledgements authors gratefully acknowledge the financial support of the international fund for agricultural development (ifad) and united states agency for international development (usaid) through a project entitled “cereal systems initiative for south asia (csisa-bd).thanks to the bangladesh agricultural research institute (bari), regional agricultural research station (rars), jessore for providing the trial land. authors also very grateful to dr. bhagirath singh chauhan for providing the trial concept and dr. elizabeth hymphres for improvement the quality of this manuscript. 24 ahmed et al. references ahmed, s., t.h. awan, m. salim and b.s. chauhan. 2015. economics of nitrogen and integrated weed management in dry seeded rice. j. ani. plant sci. 25: 1675-1684. ahmed, s. and b.s. chauhan. 2015. efficacy and phytotoxicity of different rates of oxadiargyl and pendimethalin in dry-seeded rice (oryza sativa l.) in bangladesh. crop prot. 72: 169-174. ahmed, s., m. salim and b.s. chauhan. 2014. effect of weed management and seed rate on crop growth under direct dry seeded rice systems in bangladesh. plos one doi:9(7):10.1371/journal.pone.0101919. ahmed, s. and b.s. chauhan. 2014. performance of different herbicides in dryseeded rice in bangladesh. scient world j doi:10.1155/2014/729418. awan, t.h., p.c. stacruz, and b.s. chauhan. 2016. effect of pre-emergence herbicides and timing of soil saturation on the control of six major rice weeds and their phytotoxic effects on rice seedlings. crop prot. 83: 3747. bari, l. and s. ahmed. 2018. performance of aus rice in different tillage systems and crop establishment method in southwest bangladesh. j. exp. sci. 9: 05-09. brri. 2011. modern rice cultivation, sixteen ed. bangladesh rice research institute,gazipur, bangladesh. p.72. chauhan, b.s. and d.e. johnson. 2011. growth response of direct-seeded rice to oxadiazon and bispyribac-sodium in aerobic and saturated soils. weed sci. 59: 119–122. chauhan, b.s. and j. opeña. 2012. effect of tillage systems and herbicides on weed emer-gence, weed growth, and grain yield in dry-seeded rice systems. field crops res. 137: 56–69. dhareesank, a., k. kobayashi and k. usui. 2006. residual phytotoxic activity of pethoxamid in soil and its concentration in soil water under different soil moisture conditions. weed biol. manag. 6: 50–54. dickmann, r., j. melgarelo, p. loubiere and m. montagnon. 1997. oxadiargyl: a novel herbicide for rice and sugarcane. in proceedings british crop protection conference-weeds, brighton, uk.pp. 51-57. gitsopoulos, t.k. and r.j. froud-williams. 2004. effects of oxadiargyl on directseeded rice and echinochloa crus-galli under aerobic and anaerobic conditions. weed res. 44: 329–334. jordan, d.l., p.k. bollich, a.b. burns and d.m. walker. 1998. rice (oryza sativa l.) response to clomazone. weed sci. 46: 374–380. khaliq, a., a. matloob, h.m. shafiq, z.a. cheema and a. wahid. 2011. evaluating sequential application of pre and post emergence herbicides in dry seeded fine rice. pak. j. weed. sci. res. 17(2): 111-123. kumar, v., and j.k. ladha. 2011. direct seeding of rice: recent developments and future research needs. adv. agron. 111: 299–413. levene, b.c. and m.d.k. owen. 1995. effect of moisture stress and leaf age on bentazon absorption in common cocklebur (xanthium strumarium) and velvetleaf (abutilon theophrasti). weed sci. 43: 7–12. rahman, m., a.s. juraimi, a.s.m. jaya suria, a.b. man, and p. anawar. 2012. response of weed flora to different herbicides in aerobic rice system. scienti. res. essays. 7(1): 12-23. riches, c.r., d. harris, d.e. johnson and b. hardy. 2008. improving agricultural productivity in rice-based system of the high barind tract of bangladesh. los baños, philippines: international rice research institute. 215 p. response of soil applied herbicides 25 si, y., k. takagi, a. iwasaki and d. zhou. 2009. adsorption, desorption and dissipation of metolachlor in surface and subsurface soils. pest manage. sci. 65: 956–962. singh, s., l. bhushan, j.k. ladha, r.k. gupta, a.n. rao and b. sivaprasad. 2006. weed management in dry-seeded rice (oryza sativa l.) cultivated in the furrow irrigated raisedbed planting system. crop prot. 25: 487–495. singh, s., j.k. ladha, r.k. gupta, l. bhushan, a.n. rao, b. sivaprasad and p.p. singh. 2007. evaluation of mulching, intercropping with sesbania and herbicide use for weed management in dry-seeded rice (oryza sativa l.). crop prot. 26: 518–524. sudhir-yadav, e. humphreys, s.s. kukal, g. gurjeet and r. rangarajan. 2011. effect of water management on dry seeded and puddled transplanted rice. part 2. water balance and water productivity. field crops res. 120: 123–132. microsoft word 12 bangladesh agron. j. 2017, 20(2): 107-113 determination ofdetermination ofdetermination ofdetermination of nutrients for potatonutrients for potatonutrients for potatonutrients for potato ----t. aust. aust. aust. aus ----t. aman t. aman t. aman t. aman rice cropping pattern under surma kushiara flood rice cropping pattern under surma kushiara flood rice cropping pattern under surma kushiara flood rice cropping pattern under surma kushiara flood plain in aezplain in aezplain in aezplain in aez----20202020 m. i. nazrulm. i. nazrulm. i. nazrulm. i. nazrul1111**** and m. r. islamand m. r. islamand m. r. islamand m. r. islam2222 1111on-farm research division, bangladesh agricultural research institute, sylhet, bangladesh 2on-farm research division, bangladesh agricultural research institute, gazipur, bangladesh *corresponding author: emailmi_nazrul@yahoo.com (receivedreceivedreceivedreceived: 11 december 2017, accepted:accepted:accepted:accepted: 21 december 2017) keywords: keywords: keywords: keywords: nutrient management, cropping pattern, yield abstractabstractabstractabstract the experiment was carried out in the surma kushiyara floodplain soil at the farmer’s field of farming system research and development (fsrd) site, jalalpur, under south surma upazilla of sylhet district in the medium high land under agro-ecological zone (aez)-20 for the three consecutive years 2013-2016 to determine economic dose of organic and inorganic fertilizers for potato-t. aus -t. aman rice cropping pattern. the experiment was composed of four treatments viz. t1: soil test based (stb) fertilizer dose for high yield goal (hyg), t2: t1+ cd 5 t ha -1, t3: t1 along with cd 5 t ha -1 in ipns approach and t4: farmers practices for potato-t. aus -t. aman rice cropping pattern maintained in a randomized complete block design with six dispersed replications. the varieties for potato, t. aus and t. aman rice were diamont, brri dhan48 and binadhan-7, respectively. the results showed that the tuber yield of potato, grain yields of t.aus and of t. aman rice were significantly influenced by the different treatments. the increase yield of tuber 6.11t ha-1 (33.30 %), grain of t. aus 0.42 (10.24%) and t. aman 0.54 (15.52%) rice was obtained from t2 over control (t4) and also higher compared to other treatments. the treatment stb fertilizer for hyg + 5 t ha-1 of cd also showed 25.03% higher t. aman rice equivalent yield (22.53 t ha-1) compared to farmers practice (t4) treatment. the monetary values for the whole cropping pattern showed that the highest benefit cost ratio (2.03), gross return (tk. 4,61,865 ha-1) and gross margin (tk.2,33,735 ha-1) were obtained from stb fertilizer for hyg + 5 t ha-1 of cd. the treatment ipns based on fertilizer management with cowdung for hyg had no significant effect on the yield of first and succeeding crops. so, considering crop productivity and economic return, soil test based fertilizer for high yield goal with 5 t ha-1 cowdung could be recommended for the potato t. aus t. aman rice cropping pattern for aez-20 of sylhet region. introductionintroductionintroductionintroduction fertilizer is one of the most important factors to increase the productivity of crops (anon., 1997). in bangladesh, fertilizers are generally recommended for each crop without considering the residual effect of fertilizers applied to the previous crops. nitrogenous fertilizers have very little residual effect on the subsequent crops as it is lost through leaching, volatilization, denitrification, etc. but the fertilizers like phosphate, potash, zinc, and sulphur have considerable residual effect on the following crops. higher cropping intensity, introduction of high yielding crop varieties, improper cropping sequence and faulty management practices led to a sharp depletion of soil fertility. fallow t. aus t. aman rice is one of the dominant cropping 108 nazrul & islam patterns in this region under rainfed condition in medium highland to lowland areas of surmakushyara floodplain (kaisar et al., 2007). potato is a promising crop, which can be cultivated in fallow land of this area. at present, the potato is being cultivated by farmers and it becoming a commercial crop in this area. to enhance potato production, practice of potato-rice based improved pattern can be an economically viable and improved cropping pattern instead of existing fallow-t. aus-t. aman rice cropping pattern for utilization of fallow land in sylhet region (nazrul et al., 2013). however, this improved pattern has been developed but the farmers are not aware of suitable fertilizer doses for this pattern. the development of appropriate nutrient management technologies for different cropping pattern is the most important and should be the immediate goal of soil fertility research. the present study was undertaken to find out a cropping pattern based fertilizer recommendation and to determine the economically profitable dose of fertilizer for potatot. aus-t. aman rice cropping pattern under surma-kushyara floodplain soil. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the experiment was carried out in the surma-kushiyara floodplain soil at the farmer’s field of farming system research and development (fsrd) site, jalalpur, under south surma upazilla of sylhet district in the medium high land under aez-20 for the three consecutive years 20132016 to determine economic combined dose of organic and inorganic fertilizers for potato-t. aus -t. aman cropping pattern. the varieties for potato, t. aus and t. aman rice were diamont, brri dhan48, and binadhan-7, respectively. the fertilizer treatments used in the experiment was based on fertilizer recommendation guide (frg, 2012). soil samples were collected from farmers’ field and analyzed at srdi laboratory, sylhet for chemical analysis. the chemical properties of the soil are presented in table 1. four different fertilizer packages viz. t1: soil test based (stb) fertilizer dose for high yield goal (hyg), t2: t1+ cd 5 t ha -1, t3: t1 along with cd 5 t ha-1 in ipns approach and t4: farmers practices (average of 25 farmer’s data) were tested. in all the crops n, p, k, s, and zn were applied through urea, triple super phosphate, murite of potash, gypsum, and zinc sulphate, respectively. the experiment was laid out in a randomized complete block design with six dispersed replications. the unit plot size was 10 m × 4 m for the whole cropping pattern. on basis of soil analysis, fertilizer doses were estimated with the help of soil analysis value as per treatment. the estimated fertilizer doses for potato, t. aus and t. aman rice were presented in the table 2. almost all the nutrients were low to very low except zinc (medium) and boron (low). table 1. soil analysis values of different samples collected from farmers fields replications ph om (%) total n (%) k p s zn b meq/100g soil micro gram/g soil 1 5.40 1.56 0.07 0.11 2.46 10.80 1.24 0.33 2 4.50 1.07 0.05 0.12 12.53 12.31 1.11 0.51 3 5.53 0.98 0.06 0.16 11.32 8.31 1.00 0.56 4 5.51 1.26 0.06 0.11 11.99 8.31 1.15 0.54 5 4.70 1.21 0.07 0.14 9.87 11.52 1.08 0.62 6 5.48 1.27 0.06 0.13 8.59 9.14 1.22 0.48 average 1.23 0.06 0.13 9.46 10.07 1.13 0.51 sa l vl l l l m op sa: strongly acidic, l: low, vl: very low, op: optimum, m: medium 109 determination of fertilizer nutrients for potato-t. aus-t. aman rice table 2. treatment-wise fertilizer doses for crops under potato t. aus t. aman rice cropping pattern at fsrd site, jalalpur, sylhet treatments potato t. aus t. aman n p k s zn cd n p k s n p k s kg ha-1 t1: stb fertilizer for hyg 151 29 66 14 0.5 0 76 11 27 7 91 11 36 9 t2: t1+cd 5tha -1 151 29 66 14 0.5 5000 76 11 27 7 91 11 36 9 t3: t1with 5tha -1 cd in ipns 126 22 55 14 0.5 5000 76 11 27 7 91 11 36 9 t4: farmers practice (fp) 180 50 70 25 2.0 0 110 20 40 15 60 15 30 0 note: cd: cowdung, hyg: high yield goal, ipns: integrated nutrient system. farmers practices (fp) as control. the potato (solanum tuberosum l.) tubers were sown from 20-25 november in three consecutive years. seeds (tubers) were sown at the rate of 1.5 t ha-1 and spacing was 60 cm x 25 cm. entire amount of cowdung, tsp, mop, gypsum, and zinc sulphate and one half amount of urea was applied at final land preparation and remaining one-half urea was top dressed at 30-35 days after seeding (das) before earthing up. two irrigations were done at 20-25 and 45-50 das. the fungicides, indofil and secure were applied at 35 and 45 das, respectively for late blight control. the tuber of potato was harvested from 25-27 february in three consecutive years. after potato harvest, the second crop t. aus rice (oryza sativa) was transplanted on the same plot from 15-20 april. twenty-five-days old seedlings were used with spacing was 20 cm x 15 cm. half of n, the full dose of other fertilizers were applied during final land preparation. the rest of n-fertilizer was top dressed at 35 days after transplanting (dat). once weeding was done at 30 dat. the insecticide dursban 20 ec was applied for rice bug control. the crop was harvested from 25-28 july at full maturity. third crop t. aman rice was transplanted from 25-30 july. twenty days old seedlings were used with spacing was 20 cm × 15 cm. except nfertilizer the full dose of other fertilizers were applied during final land preparation. n-fertilizer was top dressed in two equal splits at 30 and 45 dat. dimecron insecticide was applied for controlling rice stem borer. the crop was harvested from 05-10 november at full maturity. data on tuber of potato and grain yield rice were recorded from 6m2 area. collected data were analyzed statistically and the means were separated by lsd at 5% level (gomez and gomez, 1984). the cost and return analysis were done considering the prices of nutrients, products and additional costs only following the method suggested by perrin et al. (1979). results and discussionresults and discussionresults and discussionresults and discussion tuber tuber tuber tuber yield of potatoyield of potatoyield of potatoyield of potato tuber yield of potato responded significantly to different fertilizer treatment packages (table 3). on an average, tuber yield of potato ranged from 18.35 to 24.46 t ha-1. the highest tuber yield (24.46 t ha-1), was obtained in t2 and significantly higher than all other treatments. the lowest tuber yield (18.35 t ha-1) was recorded in fp as control (t4) treatment. 110 nazrul & islam the increase yield of tuber 6.11t ha-1 (33.30 % increases) was obtained from t2 over control (t4), which was also higher compared to other treatments. on the contrary, the treatment packages incorporated with cowdung (t2 and t3) performed better and provided higher yield of potato tuber compared to other treatments. it might be the beneficial effects of cowdung as organic matter which improves microclimates of underground soil, increase water holding capacity and other micronutrients availability. the results are corroborated with the findings of ahmed et al., (2012) reported that the tuber yield and yield attributes of potato were increased with the increasing of cowdung up to 15 t ha-1 thereafter declined. organic manures viz., cowdug helps to improve soil texture, structure, soil aeration and water holding capacity. it also supplies different plant nutrient elements especially zn, b, s and mg, which is not only increase the yield but also improve the qualities like size, dry matter and nutrient content of potato (taya et al., 1994). graingraingraingrain yyyyield performance ield performance ield performance ield performance of transplantedof transplantedof transplantedof transplanted aus (aus (aus (aus (t. aust. aust. aust. aus) rice) rice) rice) rice there was a significant and positive effect of different treatments of fertilizers packages on grain yield of t. aus rice (table 4) over three consecutive years. the highest grain yield (4.52 t ha-1) was recorded in t2 (t1 + cd 5 t ha -1), which was statistically different from all other treatments. the lowest grain yield (4.10 t ha-1) was recorded in control (t4) treatment, which was also significantly different with all other treatments. the grain yield was 0.42 t ha-1 i.e., 10.24 % increase in t2 treatment over farmers practices (t4). it also appeared that the treatment t2 which contained higher amount of fertilizer nutrients gave higher yield compared to others treatments including fp. it might be due to residual effect of chemical fertilizers and cowdung applied to the previous crop (potato). it revealed that application of cowdung has little effect on the yield of first succeeding crops. the average grain yield of rice varied from 4.10 to 4.52 t ha-1 in the experimentation. grain ygrain ygrain ygrain yield performance of transplanted aman (t. aman) rice ield performance of transplanted aman (t. aman) rice ield performance of transplanted aman (t. aman) rice ield performance of transplanted aman (t. aman) rice the grain yield of t. aman rice was significantly affected due to the different treatments (table 5). the grain yield varied from 3.48 to 4.02 t ha-1 (table 5). on an average the highest grain yield (4.02 t ha-1) was recorded from t2 (stb fertilizer dose for hyg + cd 5 t ha -1) which was significantly different with all other treatments. the lowest grain yield (3.48 t ha-1) was observed in (t4) as control. the results indicated that stb fertilizer dose for hyg + 5 t ha -1 of cd (t2) gave higher grain yield (0.54 t ha-1) of t. aman rice, which was 15.52 % increased over fp. jha et al. (2004) also reported that chemical fertilizers + cd produced significantly higher grain yield compared with the application of inorganic fertilizer alone. rrrrice equivalent yield ice equivalent yield ice equivalent yield ice equivalent yield as comparing the treatments effect, yields of potato tuber and t. aus rice was converted into t. aman rice equivalent yield on the basis of prevailing market price of individual crops. the highest rice equivalent yield was recorded from stb fertilizer dose for hyg + cd 5 t ha-1 (t2) due to the highest yield of potato, t. aus and t. aman rice crops. the treatment comprises of t1 and t1 with 5 tha -1 cd in ipns treatments failed to show higher rice equivalent yield than stb fertilizer dose for hyg + cd 5 t ha-1 (t2). farmer’s practice showed lowest rice equivalent yield due to lower yields of all three crops (table 6). the highest percent of rey (25.03 %) was obtained from t2 (t1+ cd 5 t ha -1) over farmers practices (t4) treatment. agroagroagroagro----economic performanceeconomic performanceeconomic performanceeconomic performance cost and return analysis of different treatments on potato t. aus t. aman rice cropping patterns during 2013-16 have been presented in table 7. 111 determination of fertilizer nutrients for potato-t. aus-t. aman rice table 3. effects of different treatments on the tuber yields of potato under potato – t. aus -t. aman rice cropping pattern at frd site, jalalpur, during 2013-16. treatments tuber yield (t ha-1) of potato yield increase over fp 2013-14 2014-15 2015-16 pooled (t ha-1) (%) t1: stb fertilizer for hyg 22.13 18.42 20.11 20.22 1.87 10.19 t2: t1+cd 5tha -1 25.79 24.10 23.49 24.46 6.11 33.30 t3: t1 with 5tha -1 cd in ipns 23.52 20.58 20.90 21.67 3.32 18.09 t4: farmers practice (fp) 19.34 17.25 18.47 18.35 lsd (0.05) 1.64 1.77 1.28 1.56 cv (%) 3.62 4.40 3.09 3.70 table 4. effects of different treatments on the grain yields of t. aus rice under potato-t. aus-t. aman rice cropping pattern at frd site, jalalpur, during 2013-16 treatments grain yield (t ha-1) of t. aus rice yield increase over fp 2013-14 2014-15 2015-16 pooled (t ha-1) (%) t1: stb fertilizer for hyg 4.61 4.18 4.01 4.27 0.17 4.15 t2: t1+cd 5tha -1 4.85 4.43 4.27 4.52 0.42 10.24 t3: t1 with 5tha -1 cd in ipns 4.96 4.04 3.93 4.31 0.21 5.12 t4: farmers practice 4.61 3.98 3.72 4.10 lsd (0.05) 0.36 0.15 0.16 0.22 cv (%) 4.67 1.81 2.57 3.02 table 5. effects of different treatments on the grain yields of t. aman rice under potato-t. aust. aman rice cropping pattern at frd site, jalalpur, during 2013-16 treatments grain yield (t ha-1) of t. aman rice yield increase over fp 2013-14 2014-15 2015-16 pooled (t ha-1) (%) t1: stb fertilizer for hyg 3.55 3.75 3.82 3.71 0.23 6.61 t2: t1+cd 5 tha -1 3.85 3.94 4.28 4.02 0.54 15.52 t3: t1 with 5tha -1 cd in ipns 3.57 3.91 3.95 3.81 0.33 9.48 t4: farmers practice 3.21 3.70 3.53 3.48 lsd (0.05) 0.33 0.14 0.25 0.24 cv (%) 4.62 1.77 3.28 3.22 the highest gross return (tk.4,61,865 ha-1) was obtained from t2 (t1 + cd 5tha -1) which was about 10% higher than t3, 16% than t1, 25% than farmer’s practice. among the fertilizer treatment, the lowest gross return was recorded from farmer’s practice. the highest gross 112 nazrul & islam margin (tk. 2, 33,735 ha-1) and benefit cost ratio (2.03) was also obtained from t2 followed by tk. 1,93,710 ha-1 obtained from t3 (t1 with 5tha -1 cd in ipns) treatment. the treatment t4 (fp) produced the lowest gross margin (tk. 1, 44,173 ha-1) and bcr (1.64) over control treatment. the treatment t1 and t3 failed to show higher benefit than t2 due to lower yield of all crops. table 6. t. aman rice equivalent yield of different treatments under potato-t. aus-t. aman rice cropping pattern at frd site, jalalpur, during 2013-16 (average). treatments rice equivalent yield (t ha-1) t. aman yield (t ha-1) total t. aman rey (t ha-1) % increase rey over fp potato t. aus t1: stb fertilizer for hyg 11.83 3.83 3.71 19.37 7.49 t2: t1+cd 5tha -1 14.32 4.19 4.02 22.53 25.03 t3: t1with 5tha -1 cd in ipns 12.68 3.99 3.81 20.48 13.65 t4: farmers practice 10.74 3.80 3.48 18.02 table 7. cost and return analysis of different fertilizer packages in potato-t. aus-t. aman rice cropping pattern at frd site, jalalpur, during 2013-16. treatments gross return (tk. ha-1) total variable cost (tk.ha-1) gross margin (tk.ha-1) benefit cost ratio (bcr) t1: stb fertilizer for hyg 397085 220630 176455 1.79 t2: t1+cd 5tha -1 461865 228130 233735 2.03 t3: t1with 5tha -1 cd in ipns 419840 226130 193710 1.85 t4: farmers practice 369410 225237 144173 1.64 price of price of price of price of inputs (tk. kginputs (tk. kginputs (tk. kginputs (tk. kg----1111):):):): rice-40.00; potato = 30.00; urea= 16.00; tsp-22.00; mop = 15.00; gypsum=10.00; zinc sulphate = 55.00; cowdung =1.50. ploughing cost = tk. 10 decimal-1; labour cost = tk. 300 man-1day-1. price of outputs (tk. ka-1): potato = 12.00; t. aus rice = 19.00; t. aman rice=20.50. conclusionconclusionconclusionconclusion from the above study, it may be concluded that the stb fertilizer dose for hyg + cd 5 t ha-1 (t2) was found agronomically viable and economically profitable under potato-t. aus-t. aman rice cropping pattern at agro-ecological zone -20 of sylhet region. so, considering crop productivity and economic return; stb fertilizer nutrients for hyg + cd 5 t ha-1 (t2) could be recommended for the potato t. aus t. aman rice cropping pattern under surma-kushayara floodplain soil. 113 determination of fertilizer nutrients for potato-t. aus-t. aman rice referencesreferencesreferencesreferences ahmed, m., s. n. mozumder, m. moniruzzaman, m. z. ali, m. m. r. sarker and a. b. m. a. uddin. 2012. effect of cowdung and sulphur on agro-economic performance of potato tubers in bangladesh. bull. inst. trop. agr., kyushu univ. vol. 35 (1): 033-039. anonymous. 1997. fertilizer recommendation guide, bangladesh agricultural research council, farmgate, dhaka. p.185 gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research (2nd ed.). jhon willey & sons, new york. kaisar, m. o., m. asaduzzaman, a. k. choudhury, and khalequzzaman. 2007. development of fertilizer recommendation for fallow -t. aus -t. aman cropping pattern under surmakushyara floodplain soil. j .soil. nature. 1(2): 35-38 nazrul, m. i., m. r. shaheb, m. a. h. khan and a. s. m. m. r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16 (2): 41-50. perrin, r. k., d. l. winkelman, e. r. moseardi and j. r. anderson. 1979. farm agronomic data on farmer’s recommendations. information bulletin 27, cimmyt. mexico. taya, j. s., y. s. malik, m. l. pandita and s. c. kumara. 1994. fertilizer management on potato based cropping system. 1: growth and yield of potato. j. indian potato asso., 1(3-4): 164188. bangladesh agron. j. 2019, 22 (1): 89-93 fertilizer management for maximizing soybean (glycine max l.) production in saline agro-ecosystem of barguna m.j. hasan1, s. ahmed2*, m.a. rahman1 and s.c. samanta2 1ms student, department of agronomy, patuakhali science and technology university, dumki, patuakhali8602 2professor, department of agronomy, patuakhali science and technology university, dumki, patuakhali-8602 *corresponding e-mail: sultanpstu@yahoo.com (received: 24 july 2019, accepted: 24 october 2019) keywords: fertilizer dose, soybean, saline eco-system, yield abstract an experiment was conducted at saline agro-ecosystem of burir char union, barguna district during january to june 2018, with a view to find out the fertilizer management for maximizing soybean (glycine max l.) production in saline agro-ecosystem was laid out in randomized complete block design consisted of three varieties of soybean and four levels of fertilizer doses with three replications. three varieties of soybean viz. bari soybean-5, bari soybean-6 and binasoybean-3 and four fertilizer levels viz. t1 = 25-30-45-10-1.0-1.0 kgha -1 n-p-k-s-zn-b (soil test based fertilizer); t2 = 30-40-60-12-2.0-1.0 kgha-1 n-p-k-s-zn-b (fertilizer recommendation guide, 2012); t3 = 40-20-15-0-0-0 kgha -1 n-pk-s-zn-b (farmers practices); t4 = control native fertility were considered which placed in a factorial randomized block design. the variety had significant influence on plant height, branches plant-1, number of filled pods plant-1, number of unfilled pods plant-1, seed yield plant-1, seed yield (t ha-1), stover yield (t ha-1). bari soybean-6 performed better than the other two varieties. the fertilizer doses had significant influence on plant height, branches plant-1, number of filled pods plant-1, number of unfilled pods plant-1, seed yield plant-1, 100-seed weight, seed yield (t ha-1), stover yield (t ha-1). fertilizer doses 25-30-45-10-1.0-1.0 kgha-1 n-p-k-s-zn-b (soil test based fertilizer) gave the maximum yield. the interaction between variety and fertilizer doses v2t1 (bari soybean-6 and 25-30-4510-1.0-1.0 kgha-1 n-p-k-s-zn-b) produced the maximum yield so, the variety bari soybean-6 with fertilizer dose 25-30-45-10-1.0-1.0 kgha-1 n-p-k-s-zn-b could be suitable combination for higher yield of soybean in saline agro ecosystem of barguna. introduction soybean (glycine max l.) is an important global legume crop that grows in the tropical, subtropical and temperate climates. its seed contains about 40% protein and 20% oil, provides approximately 60% of the world supply of vegetable protein and 30% of the oil (fehr, 1989). soybean is an important source of human dietary protein with an average of 40% content, 30% carbohydrate and oil content of 20% (adu-dapaah et al., 2004; mofa and csir, 2005). as a grain legume, it is gaining important position in the agriculture of tropical countries including bangladesh. now, soybean producing areas are barisal, bhola, faridpur, patuakhali, meherpur, jessore, rangpur, kurigram, thakurgaon, tangail, mymensingh, jamalpur, chandpur, feni, noakhali and laxmipur (chowdhury et al., 2013). farmers of this area generally grow local variety of soybean with no or limited application of fertilizer. for this reason, the yield of soybean in this 90 hasan et al. region is much below than that of potential yield level. balanced fertilization can play a major role to enhance the present yield level. although soybean can fix atmospheric n in soil which is necessary for better yield. fertilizer recommendation solely based on crop response data often fails to show economic viability. since the application of optimum dose of fertilizer is important for increasing the yield of soybean, but very limited information in this regard is available in bangladesh. the present study was undertaken to find out salt tolerant variety and develop a fertilizer management practices for coastal area. materials and methods the experiment was conducted at saline agro-ecosystem of barguna during january to june 2018 with geographical location of 22.1508 n latitude and 90.1264 e longitude at the elevation of 1.5 m above the sea level. before conducting the experiment the initial composite soil sample (0-15cm) were collected from the experiment plot. the land was clay loam in texture having a soil ph value of 7.9, moderate in organic matter content. soil characteristics of the experimental plot have been presented in table (1). the experiment was laid out in a factorial randomized complete block design (rcbd) with 3 replications. the variety bari soybean -5, bari soybean-6 and bina soybean-3 was used as test crops. the unit plot size was 4m × 3m.spacing 30 cm× 10 cm. four fertilizer treatments viz.; t1 : 25-30-45-10-1.0-1.0 kgha -1 n-p-k-s-zn-b (soil test based fertilizer)), t2: 30-40-60-12-2.0-1.0 kgha-1 n-p-k-s-zn-b (fertilizer recommendation guide, 2012) t3 : 40-20-15-0-0-0 kgha -1 n-p-k-s-zn-b (farmers practices) and t4 : native fertility (control) were applied half of urea and entire amount of other fertilization was applied as basal during final land preparation and the remaining half of urea was applied as top-dressed after 21 days of sowing. first irrigation was applied after 35 days after sowing before flowering and the second irrigation was applied at pod formation stage. different intercultural operations and plant protection measures was taken as and when necessary to raise healthy crop. data were collected on an individual plant basis and seed yield plant-1 (g) was estimated after cleaning and proper drying. plot yield was recorded (3m2 from each plot) and then converted to t ha-1. all data were statistically analyzed using ‘analysis of variance technique’ with the help of mstatc computer program and the mean difference were compared by duncan’s multiple range test at 5% level of significance. table 1. chemical properties of soil (0 -15 cm depth) collected before cultivation of thecrop in experimental field at barguna soil properties values a. physical properties 1. particle size a. sand (%) 19.17 b. silt (%) 54.82 c. clay (%) 26.01 2. soil textural class silty clay b. chemical properties 1. soil ph 7.9 2. electrical conductivity 6.34 ds m-1 3. organic carbon 0.35 4. organic matter 1.42 5. total n (%) 0.071 6. available p (ppm) 8.49 7. available s (μg/100 g soil) 0.58 8. exchangeable k 0.18 9. boron (μg/100 g soil) 0.59 results and discussion fertilizer management for maximizing soybean production 91 plant height the effect of variety and different fertilizer treatments on the plant height is presented in table 2. there were significant variations among variety and treatments. in case of variety the highest plant height (52.20 cm) was observed in bari soybean-6 and shortest plant height (48.12 cm) in bari soybean-5.in case of fertilizer doses, the highest plant height (51.26 cm) was observed in t1 and shortest plant height (44.20 cm) in t4. incase of interaction effect of variety and treatment in table 3, the highest plant height (45.67 cm) was observed inv2t2 and shortest plant height (33.58 cm) was observed in v3t4. hasio et al. (1976) stated that plant height is the function of vertically cell enlargement and it is an important morphological character that influenced by growing condition such as plant variety. number of filled pods per plant-1 table 2 showed there was no significant differences in variety but fertilizer treatment had significant effect where the highest number of filled pods plant-1 (43.69) was produced in t1 and the lowest number of filled pods plant -1 (33.78) in t4 treatment. in case of interaction effect of variety and fertilizer dose (table 3), the highest number of filled pods plant-1 (51.33) was produced in v2 t1 and the lowest number of filled pods splant-1 (23.60) s in v1t4. this result was in conformity with the findings of karte et al. (1983). table 2. effect of variety and fertilizer dose on plant height, seeds pod-1, filled pods plant-1, 100-seed weight, seed yield and stover yield treatments plant height (cm) number of seeds pod1 number of filled pods plant-1 100-seed weight (g) seed yield (t ha-1) stover yield (t ha-1) variety bari soybean5 48.12 2.44 b 38.35 a 7.92 a 1.75 ab 4.63 b bari soybean6 52.20 2.68 a 41.07 a 7.67 b 1.78 a 4.73 a binasoybean-3 49.11 2.43 b 36.72 a 7.42 b 1.73 b 3.62 c lsd(0.05) 5.49 0.19 6.21 1.18 0.91 1.15 cv (%) 3.82 9.57 8.20 14.41 2.15 12.67 fertilizer dose t1 51.26 2.50 a 43.69 a 8.00 1.86 a 4.98 b t2 47.39 2.45 a 35.69 b 8.44 1.80 b 5.28 a t3 46.85 2.44 a 39.02 ab 7.88 1.70 c 4.98 b t4 44.20 2.42 b 33.78 b 7.66 1.65 d 3.08 c lsd(0.05) 6.34 0.23 7.50 1.36 0.05 1.33 cv (%) 3.82 9.57 8.20 14.41 2.15 12.67 common letters do not differ significantly by duncan’s multiple range test at 5% level of significance t1 : 25-30-45-10-1.0-1.0 kgha -1 n-p-k-s-zn-b (soil test based fertilizer)), t2: 30-40-60-12-2.01.0 kgha-1 n-p-k-s-zn-b (fertilizer recommendation guide, 2012) t3 : 40-20-15-0-0-0 kgha -1 n-p-k-s-zn-b (farmers practices) and t4 : native fertility (control) 100-seed weight 90 hasan et al. significantly highest 1000-seed weight was obtained from bari soybean 5. in case of fertilizer treatment, there was no significant difference was found. butinter action effect of variety and fertilizer dose (table 3) showed significant where the maximum 100-seed weight (9.33 g) was obtained from v1t1 and v1t2 and the lowest 100-seed weight (7.00 g) from v3t4.the present results were in agreement with those of singh and singh (1995) who reported that 100-seed weight increased by stb based fertilizer dose over control due to optimum uptake of nutrients. table 3. interaction effects of variety and fertilizer dose on plant height, number of seeds pod-1, number of filled pods plant-1,100-seed weight, seed yield and stover yield variety/ × fertilizer dose plant height (cm) number of seeds pod-1 number of filled pods plant-1 100-seed weight (g) seed yield (t ha-1) stover yield (t ha-1) v1t1 44.07 ab 2.46 abc 38.20 b 9.33 a 1.59 abc 5.40 ab v1t2 35.57 cde 2.50 abc 38.33 b 9.33 a 1.44 bcde 4.90 abc v1t3 44.33 ab 2.53 ab 37.27 b 8.67 ab 1.35 bcdef 4.33 bcd v1t4 33.69 de 2.27 d 23.60 d 8.33 abc 1.14 ef 3.90 cde v2t1 44.41 ab 2.63 a 51.33 a 7.33 c 1.82 a 6.07 a v2t2 45.67 a 2.30 cd 27.00 cd 8.00 bc 1.22 def 3.40 de v2t3 38.82 bcd 2.47 abcd 42.80 ab 7.33 bc 1.49 abcd 4.73 bc v2t4 40.61 abc 2.53 ab 43.13 ab 8.00 bc 1.62 ab 4.73 bc v3t1 44.04 ab 2.50 abc 27.13 cd 7.33 bc 1.13 ef 3.13 de v3t2 42.75 ab 2.33 bcd 41.40 b 8.00 abc 1.51 abcd 4.87 abc v3t3 39.97 abc 2.50 abc 28.00 cd 7.33 bc 1.27 cdef 3.60 cde v3t4 33.58 e 2.43 abcd 34.33 bc 7.00 c 1.02 f 2.87 e lsd (0.05) 5.49 0.19 6.22 1.18 0.91 1.15 cv (%) 3.82 9.57 8.20 14.41 2.15 12.67 common letters do not differ significantly by duncan’s multiple range test at 5% level of significance t1 : 25-30-45-10-1.0-1.0 kgha -1 n-p-k-s-zn-b (soil test based fertilizer)), t2: 30-40-60-12-2.01.0 kgha-1 n-p-k-s-zn-b (fertilizer recommendation guide, 2012) t3 : 40-20-15-0-0-0 kgha -1 n-p-k-s-zn-b (farmers practices) and t4: native fertility (control) seed yield table 2 showed that the highest seed yield (1.86 t ha-1) was recorded from bari soybean 6 but at par to bari soybean 5 and the lowest frombinasoybean-3. in case of fertilizer treatment where t1 gave significantly highest seed yield and the lowest seed yield (1.65 t ha-1) from t4. interaction effect of variety and fertilizer dose showed that the maximum seed yield (1.82 t ha-1) was recorded from v2t1 and the lowest seed yield (1.02 t ha -1) from v3t4. the result was supported by the findings of paikera and mishra (1989). stover yield significant effect was found in variety where highest stover yield was recorded from bari soybean 6 (table 2). in fertilizer treatment, showed that the highest stover yield (5.28 t ha-1) was recorded from t2 and the lowest stover yield (3.08 t ha-1) from t4 in case of interaction effect of variety and fertilizer dose, the highest stover yield (6.07 t ha-1) was recorded from v2t1 and the lowest stover yield (2.87 t ha-1) from v3t4. tomar and khajanji (2009) reported that recommended dose of fertilizer (20 kg n + 60 kg p2o5+ 20 kg k2o /ha) recorded significantly higher stover yields of soybean as compared with control and 50% recommended dose of fertilizer. fertilizer management for maximizing soybean production 91 conclusion it could be concluded from the study that stb based fertilizer doses (25-30-4510-1.0-1.0 kg ha-1 n-p-k-s-zn-b ), and soybean var. bari soybean 6 are superior to the others fertilizer management packages in respect of seed yield and other characters. acknowledgement the authors avail the opportunity to express their sincere thanks and heartfelt gratitude to the government of the people’s republic of bangladesh through its ministry of science and technology (most) for providing financial support for conducting field experiment and preparation of the thesis for awarding ms degree in agronomy, patuakhali science and technology university. references adu-dapaah, h.k., b. asafo-adjei, m. owusu-akyaw, and s. amoah, 2004. sustainable soybean production in ghana. paper presented at a radio program on soybean in ghana. chowdhury, m.m.u., m.j.u. sarker, a.k. choudhury, i.s.m. farhad, s.k. bhowal and k.m. f. hossain. 2013. soybean cultivation in coastal area of noakhali. on-farm research division, bangladesh agri. research institute, gazipur, bangladesh. p.1. fehr, w.r. 1989. soybean, importance and distribution.pp.283-300. in: robblen, g.r.k. downy and ashri (ed). oilcrops of the world.mc-graw-hill.pub.com. new york. hasio, t.c., e. acevedo, e. fereres and w.d. henderson. 1976. phil. r. soc. bot. 273: 275-500. karte, l.l., j.e. spetch, j.h. williams and r.c. sorensen. 1983. fertilizer of soybean genotypes during reproduction ontogeny i. agronomic responses. crop sci. 23(3): 521-527. paikera, a. and s.n. mishra. 1989. a note on effect of varying levels of nitrogen and phosphorus on yield attributes and yield of soybean. department of agronomy, orissa university of agriculture and technology, bhubaneswar, 751003, india. orissa j. agril. res. 2(1): 68-69. singh, d. and v. singh. 1995. effect of potassium, zinc and sulphur on growth characters, yield attributes and yield of soybean (glycine max). indian j. agron. 40(2): 223-227. tomar, g.s., s.n. khajanji. 2009. effect of organic manuring and mineral fertilizer on the growth, yield and economics of soybean (glycine max (l.) merrill). intl. j. agri. sci. 5(2): 590-594. microsoft word 14. baj-303_revised bangladesh agron. j. 2017, 21(1): 125-129 performance of mixed cropping of lentil with cowpea under variable seeding ratios i. s. m. farhad1*, e. jahan2, m. a. rahman3, m.g.azam4 and t. a. mujahidi5 1soil science division, bari, gazipur, bangladesh, 2department of agricultural chemistry, sau, dhaka, bangladesh, 3department of agronomy,sau, dhaka bangladesh, 4 rars, bari, hathazari, chittagong, bangladesh, 5plant breeding division, bari, gazipur, bangladesh *corresponding author, e-mail:farhadsau@gmail.com (received: 31 january 2018, accepted: 20 march 2018) keywords: mixed cropping, lentil, cowpea and equivalent yield abstract the field experiment was carried out at south lemua, mlt site, feni (aez 19) during rabi season of 2015-16 to evaluate the performance of lentil as mixed crop with cowpea under variable seeding ratio. the treatment combinations used for the experiment were t1= sole lentil (100 %) @ 40 kg seed ha-1, t2 =sole cowpea (100%) @ 45kg seed ha-1, t3 = lentil (100%) + cowpea (10 %), t4 = lentil (100 %) + cowpea (20 %) and t5 = lentil (100 %) + cowpea (30 %). lentil var. barimashur-6 and cowpea variety bari felon-1 were used in this study. the yield of lentil decreased with the increase of cowpea population in the mixed cropping situation. all the mixed cropping combinations showed higher lentil equivalent yield (ley), land equivalent ratio (ler), net return and benefit cost ratio (bcr) than sole cropping. the highest lentil equivalent yield (1438 kg ha-1) and maximum land equivalent ratio (1.24) were observed in t4 treatment. cost and return analysis showed that the highest net return (tk. 77,890 ha-1) was found in t4 treatment while sole cowpea gave the lowest net return (tk. 7530 ha-1). the highest benefit cost ratio (3.09) was recorded from lentil (100 %) + cowpea (20 %) whereas the minimum (1.21) from sole cowpea. introduction in bangladesh, pulses play a vital role in agriculture as well as in human diets. the average yield of pulses is 1.01 t ha-1, which is low compared to other neighboring countries (bbs, 2016).the area under pulse crops has declined while the area under rice production has increased (das and kabir, 2016). but the demand of pulses is increasing continuously. lentil is the most popular pulse crop in bangladesh. it plays an important role in human diets and also in improving soil fertility by fixing atmospheric nitrogen. on the other hand, cowpea (locally known as felon dahl) is very popular to the people of noakhali. farmers’ usually use local variety and get poor yield due to low yield potentiality. bari has developed some high yielding varieties of lentil and cowpea. both lentil and cowpea are cultivated as sole crop throughout the country in rabi season and sometimes as mixed crop in farmers’ field. it is observed that, some farmers of noakhali region cultivate lentil as a mixed crop with cowpea without determining benefit, cost and return and land use efficiency. generally, farmers do not maintain proper seeding ratio of mixed crop, planting time and other management practices. mixed cropping reduces the risk of total crop failure as two or crops that are more different are cultivated simultaneously in the same field. this mixed cropping system is already practicing in the farmer’s field at feni area. however, the farmers do not maintain the appropriate seedlings ration and thus, the crop with unnecessarily high population suppress the growth of other one. 126 farhad et. al. the present study was, therefore, undertaken to determine the most profitable mixed crop combination of lentil and cowpea. materials and methods the experiment was carried out at south lemua, mlt site, feni during rabi season of 2015-16. the soils of the experimental areas belong to the young meghna river estuarine flood plain (aez 19). the soils of the experimental plots were clay loam in texture. the experiment was laid out in randomized complete block design with six dispersed replications. it was consisted with five treatments as follows: t1 = sole lentil1 (100 %) @ seed rate 40 kg ha-1, t2 = sole cowpea (100 %) @ seed rate 45 kg ha-1, t3= lentil (100 %) + cowpea (10 %), t4 = lentil (100 %) + cowpea (20 %) and t5 = lentil (100 %) + cowpea (30%). according to the treatments, seeds of lentil (bari mashur-6) and cowpea (bari felon-1) were broadcasted on 7-11 december, 2015. the unit plot size was 40 m2 (10m x 4m). the lands were fertilized with 21, 18, 20, 7, 1.5 and 1.5 kg n-p-k-s-zn-b ha-1, respectively. two-third urea and entire amount of all fertilizers were applied during final land preparation as basal in all the treatment combination and rest 1/3rd urea was applied as top dress at about 30 days after broadcasting. one weeding was done at 30 days of sowing. a systemic insecticide (cypermethrene) was sprayed at seedling stage to control aphids and thrips. lentil was harvested on 10-12 march, 2016 whereas, cowpea harvesting started on 8 march and continued up to 13 april, 2016. data on the different crop parameters were collected from the 10 sample plants and then average was taken which was further analyzed by computer program crop stat. lentil equivalent yield (ley), land equivalent ratio (ler) and economic analysis were calculated to ascertain the efficiency of mixed cropping. lentil equivalent yield was calculated by converting yield of mixed crops to the yield of lentil on the basis of prevailing market prices of individual crops. lentil equivalent yield (ley) was calculated after bandyopadhyay, 1984. lentil equivalent yield yield of cowpea (kg ha-1) x price of cowpea (tk. kg-1) price of lentil (tk. kg-1) the treatments were evaluated in terms of land equivalent ratio (ler) using the following formula of willey (1981). land equivalent ratio = yield of intercropped lentil yield of solecropped lentil + yield of intercropped cowpea yield of solecropped cowpea results and discussions seed yield and yield attributes of lentil yield and yield attributes of lentil are presented in the table 1. results revealed that plant populations of lentil were varied with the percent amount of cowpea seeds used among the treatments. these results comply with that of findings bhowal et al. (2014), who observed that plant populations of lentil were varied with the percent amount of mustard seeds used among the treatments. the highest number of pod plant-1 (28) was recorded in t1 (sole lentil) followed by t3 (26). the lowest number of pod plant-1 (25) was obtained from t4 and t5 treatment. the highest 1000seed weight (22.4) was recorded in t1 followed by t3 (21.9) and t4 (21.7). the lowest 1000 seed weight (21.4) was recorded in t5 treatment where lentil (100%) + cowpea (30%) broadcasted. table 1. seed yield and yield attributes of lentil as a mixed crop with cowpea at south lemua under mlt site, feni during rabi season of 2015-16 performance of mixed cropping of lentil 127 treatments plant population m-2 (no.) plant height (cm) pods plant-1 (no.) 1000seeds weight (g) seed yield (kg ha-1) t1 190 27.5 28 22.4 1325 t3 186 26.8 26 21.9 1318 t4 184 26.5 25 21.7 1300 t5 183 25.8 25 21.4 1252 lsd (0.05) 5.18 1.10 2.10 0.10 62.36 cv (%) 6.8 3.7 5.3 5.9 9.1 t1 = sole lentil (100%), t3 = lentil (100%) + cowpea (10%), t4 = lentil (100%) + cowpea (20%), t5 = lentil (100 %) + cowpea (30%) the maximum lentil seed yield was recorded in sole situation t1 (1325 kg ha-1) which was statistically similar with t3 (1318 kg ha-1) and t4 (1300 kg ha-1) (table 1). it might be due to cumulative effect of yield contributing characters of lentil i.e. number of pods plant-1 and 1000 seed weight (g). the lowest lentil yield was recorded in the treatment t5 (1252 kg ha-1) where 100% lentil broadcasted with 30% cowpea in the mixed cropping situation. the seed yield of lentil decreased with the increasing of cowpea population in the mixed cropped situation. it might be due to competition for nutrients and less light interception between the main and the intercrops. seed yield and yield attributes of cowpea yield and yield attributes of cowpea are presented in the table 2. results indicated that plant populations of cowpea were varied with the percent amount of seeds used among the treatments. table 2. seed yield and yield attributes of cowpea as a mixed crop with lentil at south lemua under mlt site, feni during rabi season of 2015-16 treatments plant height (cm) plants m-2 (no.) pods plant-1 (no.) seeds pod-1 (no.) 1000seeds weight (g) seed yield (kg ha-1) t2 47.7 32 9 11 91 866 t3 51.0 5 11 13 94 96 t4 51.8 9 12 14 94 221 t5 49.6 12 10 12 93 251 lsd (0.05) 6.59 3.15 0.99 1.70 ns 39.7 cv (%) 8.6 7.2 6.4 3.1 6.1 8.5 t2 = sole cowpea (100%), t3 = lentil (100%) + cowpea (10%), t4 = lentil (100%) + cowpea (20%), t5 = lentil (100%) + cowpea (30%) the maximum number of pods plant-1 (12) was recorded in t4which was followed by t3 treatment. the lowest number of pod plant-1 (9) was obtained from t2 (sole cowpea). the number of seeds pod-1 varied significantly among the treatments. the maximum number of seeds pod-1 (14) was recorded in t4 which was statistically similar with t3 treatment. the lowest number of seeds pod-1 (11) was recorded in the treatment t2. seed weight did not varied significantly. the highest seed yield of cowpea (866kg ha-1) was recorded in t2 (sole cowpea) which was significantly different from other treatments where lowest seed yield (96 kg ha-1) was obtained from t3 treatment where only 10% cowpea seed was used. lentil equivalent yield (ley) and land equivalent ratio (ler) 128 farhad et. al. all the mixed crop treatments produced better lentil equivalent yield than their respective sole crop cultivation (table 3). lentil equivalent yield was increased with the increasing of cowpea seed for mixed cultivation up to 20 with 100% of lentil and thereafter it was declined with further increment of percent seeds. it might be due to excess inter plant competition for nutrients, light, water and space. the highest lentil equivalent yield of 1438 kg ha-1 was obtained from lentil (100%) + cowpea ( 20%) combination, which was 9 and 166% higher than the sole crop of lentil and cowpea, respectively (table 3). the results indicated that lentilcowpea mixed cropping could bring more benefit to farmers over sole lentil or cowpea. the maximum land equivalent ratio (ler) 1.24 was observed from the t4 treatment followed by t5(1.23). it is noted that all the mixed cropping systems showed higher ler than sole crop(table 3). it could be said that a farmer may increase his land use efficiency by 24% from mixed cropping systems from growing one hectare of land than that of their traditional sole crops cultivation. the results are in agreement with that razzaque et al. (2007) and alom et al. (2008). table 3. lentil equivalent yield (ley) and land equivalent ratio (ler) of mixed cropping of lentil with cowpea obtained from the experiment conducted at south lemua under mlt site, feni during rabi season of 2015-16 treatments seed yield (kg ha-1) ley (kg ha-1) ler lentil cowpea t1 = sole lentil (100%) 1325 1325 1.00 t2 = sole cowpea (100%) 866 541 1.00 t3 = lentil (100%) + cowpea (10%) 1318 96 1378 1.10 t4 = lentil (100%) + cowpea (20%) 1300 221 1438 1.24 t5 = lentil (100%) + cowpea (30%) 1252 251 1410 1.23 cost and return analysis cost and return analysis are presented in the table 4. gross return as well as net return was found higher in mixed crop cultivation in comparison to sole cropping. from cost and return analysis, it was observed that t4 treatment showed the highest gross margin (tk. 77,890 ha-1) followed by t5 (tk. 75,425 ha-1). the lowest gross return (tk. 43,280 ha-1) and gross margin (tk. 7530 ha-1) were obtained from sole cowpea. the highest benefit cost ratio (3.09) was recorded from t4 where as the minimum bcr (1.21) from sole cowpea t2 treatment. it is also showed that lentil is found better benefit than cowpea as sole crop in feni region. table 4. cost and return analysis obtained from the experiment conducted at south lemua under mlt site, feni during rabi season of 2015-16 treatments lentil equivalent yield (kg ha-1) gross return (tk. ha-1) total cost (tk. ha1) gross margin (tk. ha1) benefit cost ratio (bcr) t1 = sole lentil (100%) 1325 106000 36700 69300 2.88 t2 = sole cowpea (100%) 541 43280 35750 7530 1.21 t3 = lentil (100%) + cowpea (10%) 1378 110240 36925 73315 2.98 t4 = lentil (100%) + cowpea (20%) 1438 115040 37150 77890 3.09 t5 = lentil (100%) + cowpea (30%) 1410 112800 37375 75425 3.01 price of lentil per kg = tk.80 and cowpea per kg = tk. 50/ performance of mixed cropping of lentil 129 conclusion considering the yield and return it can be concluded that 100% lentil with 20% cowpea is the most profitable one as compared to other treatment combination when grown as mixed crop. from the results, it is evident that mixed cropping of lentil with cowpea is more profitable than the sole cropping and the risk of cultivation of one crop can be reduced by adopting the mixed cropping system. nonetheless, 100% lentil with 20% cowpea is the most profitable mixed crop compared to other treatment. references bandyopadhyay, s. k. 1984. nitrogen and water relations in grain sorghum legume intercropping systems. ph. d. dissertation, indian agricultural research institute (iari), new delhi 110012, india. bangladesh bureau of statistics (bbs). 2016. the year book of agricultural statistics of bangladesh. statistics division, ministry of planning, government of the people’s republic bangladesh, dhaka.p.39. bhowal,s.k,m.m.u. chowdhury, m.s. bhuiyan,a. h. m. a.faisal, i. s. m. farhadand s.k. bhowmik.2014.yield and yield attributes of lentil (lens esculenta) as a mixed crop with mustard (brassica campestris). sci. agri. 4 (2): 76-79. das, s. and w. kabir. 2016. pulses production in bangladesh: status and drivers for enhancement [version 1; not peer reviewed]. f1000research 2016, 5: 2650 (poster). razzaque, m. a., s. rafiquzzaman, m. m. m. bazzaz, a. ali and m. m. r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agril. res. 32(1): 37-43. willey, r. w. and m. r. rao. 1981. a competitive ratio for quantifying competition between intercrops. expt. agric. 16: 117-125. bangladesh agron. j. 2019, 22(2): 129-138 yield and yield attributes of short duration mustard as influenced by nutrient rates k.k. ahmed1, b. karmakar1*, b. ahmed1, s. akter2 and m.s. islam3 1adaptive research division, bangladesh rice research institute, gazipur, bangladesh. 2khulna university, khulna, bangladesh. 3bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh. *corresponding e-mail: biswajitbrri@gmail.com keywords: mustard, yield, siliqua, dry matter, bari sarisha-14 abstract mustard (brassica napus)is the important principal edible oil-producing crop in bangladesh. however, the nutrient requirement of mustard especially for the short duration variety is very much important to obtain higher yield. a field experiment was conducted to assess the requirement of major nutrients (n, p, k, and s), and to recommend fertilizers for short-duration mustard variety bari sarisha-14. there were 8 treatments t1=100% soil test based (stb) nutrients (n, p, k, s, zn & b @ 90, 25, 60, 15, 2 & 1 kg ha-1, respectively) as per fertilizer recommendation guide (frg,2012), t2=t1+ 25% n of frg, t3=t1+ 25% np of frg, t4=t1+ 25% nk of frg, t5=t1+ 25% pk of frg, t6=t1+ 25% npk of frg, t7=75% of t1 and t8= native nutrient (control). the experiment was laid out in randomized complete block design with 3 replications. the results revealed that yield and yield parameters of mustard weresignificantly influenced by the nutrient levels. the highest value of almost all the yield components and yield were obtained in t6 among the treatments. the highest seed yield (1.68 t ha-1) and the maximum stover yield (2.96 t ha-1) were obtained from the treatment (t6) containing 100% stb nutrients with additional 25% npk among the fertilizer treatments. the seed yield value was statistically higher than all other treatments except the treatment where100% stb nutrients with additional 25% np were used (t3). the highest seed yield and stover production were attributed tothe yield contributing parameters. the highest amount of all the nutrients content was found in the treatment t6 that was followed by t3 and t4 and the lowest in t8. the highest amount of n, p, k, and s content in seed of the treatment t6 was 3.75, 0.97, 0.96 and 0.78%, respectively. the highest yield was accredited to the highest amount of nutrient content in seed. it could be concluded that the treatment t6 (stb fertilizer dose + 25% npk of frg) would suitable for short duration mustard (bari sarisha-14) for getting higher yield and better performance. introduction mustard (brassica napus a.) belonging to the family brassicaceaeis one of the most important oilseed crops throughout the world after soybean (s.n.) and groundnut (s.n.). among the oilseed crops grown in bangladesh mustard holds the first position in terms of both total cultivation area and production. a total area of 3,36,542ha in bangladesh is used for mustard production with an annual production of about 3,62,860 metric ton (bbs, 2018). it is cultivated in bangladesh and covers a good acreage; however, the yield is not satisfactory due to low yield as well as nutrient mining, depletion of soil organic matter, imbalanced fertilization, scanty use of bio and organic fertilizers, and poor management practices (miah and karim, 1995). the correct application of nutrients is essential for the maximization of farm income, economic and quality product, and environmental improvement. the amount of fertilizers applied should be based on diagnostic methods. any fertilizer recommendation should consider the cost of fertilizer and its 136 ahmed et al. application, as well as the value of the product (sawedaet al., 2017).the fertility status of bangladesh soil is most uneven and it varies considerably even between two adjacent plots. fertilization of farm plots through soil analysis might be aneffective way to achieve maximum yield goal with economic benefit, to maintain soil fertility, and to avoid environmental pollution. bangladesh agricultural research institute (bari) has recently developed a short-duration mustard variety (bari sarisha-14) having a life spell of about 75 to 80 days with seed yield is about 1.4-1.6 t ha-1 which can be fitted easily in the existing cropping pattern. as such soil science division of bari is trying to fit this mustard variety in the mustard-mungbean-t.aus-t.aman cropping pattern. as a result assessment of its nutrient requirement for optimum yield through soil test based (stb) is of utmost importance. therefore, the study was undertaken to investigate the nutrient requirement based on soil test and to recommend fertilizer recommendation for short-duration mustard var.bari sarisha14. materials and methods the experiment was conducted at the central research farm of bangladesh agricultural research institute (bari), joydebpur, gazipur(24.09° n latitude and 90.26° e longitude and 8.4 m altitude) during rabi season of 2013-2014 to find out the requirement of nutrient such as n, p, k, s for bari sarisha-14. the experimental site belongs to the agro-ecological zone (aez) 28 which is characterized by clay within 50 cm from the surface and is acidic and it belongs to chhiata series and has been classified as grey terrace soils (frg, 2018). the nutritional status of the experimental field is presented in table 1.it is characterized by comparatively high rainfall, high humidity, high temperature, relatively long day period during april to september and scanty rainfall, low humidity, low temperature, and short-day period fromoctober to march.the experiment was laid out in randomized complete block design (rcbd) with three replications. the unit plot size was 4m3m and the seeds were sown continuouslyat the rate of8 kg ha-1in rows. row to row spacing was 30 cm. eight treatmentst1 = 100% soil test based (stb) nutrients as per fertilizer recommendation guide (frg, 2018), t2 = t1 + 25% n of frg, t3 = t1 + 25% npof frg, t4 = t1 + 25% nkof frg, t5 = t1 + 25% pkof frg, t6 = t1 + 25% npkof frg, t7 = 75% of t1 and t8 = native fertility (control) were tested in the experiment. the whole amount of p, k, s, zn, and half of n were applied at the time of final land preparation and the remaining n was applied 20 days after the sowing of mustard seeds. the amount of nutrients used in the treatment combination is given in table 2. table 1. native fertility status of the experimental plot (composite topsoil (0-30 cm) samples collected from the experimental plots at the central research farm, bari, gazipur ph toc (%) tsn (%) polsen (ppm) kexch. (cmol kg-1) s (g g-1) 5.9 1.41 0.089 8.4 0.21 9.4 nb: toc=total organic carbon and tsn=total soil nitrogen the crop was harvested at 80 days after sowing when the pods showed ripening signs. ten plants were selected randomly from each plot in such a way that the border effect was avoided for the higher level of precision.data on plant height (cm), number of branches plant-1, number of siliquaplant-1, weight of fresh plant (g), weight of fresh stem (g), weight of dry stem (g), weight of fresh siliqua (g), weight of dry siliqua (g), weight of 100 pod (siliqua) (g), 1000-seedweight, stover yield and seedyield were collected following standard methods.seedand stover weight was taken from the 6-m2 area from the center of each plot excluding border area. after threshing and cleaning, the weight was taken by finetuning electric balance and converted to kilogram (kg) in a dry weight basis. yield and yield attributes of short duration mustard 137 table 2.treatment combinations of different nutrients in the experimental field at the central research farm,bari, gazipur treatments treatment combination n p k s zn b kgha-1 t1 90 25 60 15 2 1 t2 112.5 25 60 15 2 1 t3 112.5 31.25 60 15 2 1 t4 112.5 25 75 15 2 1 t5 90 31.25 75 15 2 1 t6 112.5 31.25 75 15 2 1 t7 68 19 45 11.25 1.5 0.75 t8 native fertility chemical analysis of seedand stover preparation of samples: seedand stover samples were dried in an oven at 65oc for 48 hours and then ground by a grinding machine to pass through a 20 mesh sieve and stored in small paper bags into desiccators. then the samples were analyzed for n, p, k, and s content. digestion of samples with nitricperchloric acid half gram dried sample was transferred into a dry clean 100 ml kjeldahl flask. a 10 ml of di-acid (hno3: hclo4) in the ratio of 2: 1 was added. after leaving for a while, the flask was heated at a temperature slowly to rise to 200oc. heating was momentarily stopped when the dense white fumes of hclo4 occurred and after cooling, 6 ml of 6n hcl was added to it. the contents of the flask were boiled until they became sufficiently clean and colorless. p, k, and s contents of the flask were determined from this digest. digestion of samples with sulfuric acid an amount of 100 mg oven-dry ground sample was taken in a 100 ml kjeldahl flask and 1.1 g catalyst mixture (k2so4: cuso4 5h2o: selenium) in the ratio (10: 1: 0.1), 2 ml 30% h2o2 and 3 ml conc. h2so4 was added into the flask. the flask was swirled and allowed to stand for about 10 minutes. after that, the flask was heated and continued heating until the digest became colorless. after cooling, the digest was transferred into a 100 ml volumetric flask and made up to the mark with distilled water. a blank sample with requisite reagents was prepared in similarly. this digest was used for the estimation of total n following standard procedure. measurement of n, p, k and s contents in seed nitrogen determination nitrogen content of seedof plant was analyzed by micro-kjeldahl method (bremner and mulvaney, 1982). exactly 0.1 g sample was digested in a fume hood with 10 ml concentrated h2so4 in presence of k2so4 catalyst mixture (k2so4: cuso4: se = 10: 1: 1). the digest was then transferred to a distillation flask and 5 ml 40% naoh was added. nitrogen was estimated by titrating the distillate trapped in the h3bo3 indicator solution with 0.02n h2so4. phosphorus determination the total phosphorus content of different plant parts wasdetermined by using vanadomolybdate method (yoshida et al., 1972). dried plant materials were digested with concentrated hno3 and hclo4 136 ahmed et al. (nitric per-chloric acid) mixture for the determination of total p content. total p content in the extract was determined by jackson (1973) using a double beam spectrophotometer at 440nm wavelength. potassium determination total potassium was also determined by using the per-chloric acid digestion assay method (yamakawa, 1992). dried plant materials were digested with concentrated hno3 and hclo4 (nitric perchloric acid) mixture for determination of total k content. the concentration of k was determined by the atomic absorption spectrophotometer at 766 nm wavelength. sulfur determination dried plant materials were digested with concentrated hno3 and hclo4 (nitric per-chloric acid) mixture for determination of total s content which is known as nitric per-chloric acid digestion method. sulfur was estimated through theturbid metric method using bacl2. 2h2o by double beam spectrophotometer at 420 nm wavelength. statistical analysis data recorded in the experiments were statistically analyzed following procedures described by gomez and gomez (1984). analysis of variance (anova) was conducted using statistical software mstatc and means were compared with the least significant difference (lsd) test. results and discussion the influences on the agronomic parameters, yield attributes,and yield; such as plant height, dry weight of stem, fresh weight of siliqua, dry weight of siliqua, 100-siliqua weight, 1000-seed weight, seedyield, stover yield are shown in different tables and figures below. plant height the plant height of mustard was significantly influenced by different nutrition levels (table 3). the maximum plant (91.07cm) was recorded in t6 treatment (t1+25% npk i.e., recommendeddose+25% npk chemical fertilizer) which was statistically similar to all treatments except t7and control treatment (t8) with lowest plant height (72.68 cm). ali and ullah (1995) reported that the tallest mustard plant was found with the application of 120 kg n ha-1. the increase in plant height in these treatments was attributed to the availability of optimum nutrients throughout the growing season which might render the optimum and balanced nutrients from chemical fertilizer that reflected in plant height. however, the addition of extra n, p, and k had no significant effect on plant height. number of branches plant-1 nutrients rates had a significant influence to produce branches in plants (table 3). the maximumnumber of branchesplant-1 (7.20) was recorded in t6 treatment which was at par with t2 (t1+25% n) and t5 (t1+25% pk) but statistically higher from the other treatments. the lowest number of branches (3.92) was recorded in t8 treatment where no nutrition was applied. the results are in agreement with the findings of shuklaet al. (2002) who found that the application of mixed fertilizer (npks) increased the number of branches in the mustard plant.the nutrient helps in initiating buds in plants. these buds ultimately become active branches from where leaves emerge as photosynthetic organs and the flowering nodes are developed. thus it plays a vital role in increasing the crop yield. dry weight of stem plant-1 as shown in table 3, the nutrient response on stem dry weight was significant. the highest stem dry weight was observed in t6 treatment (25.74 g plant-1) which is statistically different from all other treatments. in contrast, the lowest value of stem dry weight (9.72 g plant-1) was found in t8 treatment. yield and yield attributes of short duration mustard 137 the possible reason behind might be this due to an increase in nutrition level the photosynthesis rate increases as a result of more dry matter accumulation occurs and ultimately stem dry weight increases. the results were in alignment with bhagawanet al. (1996). table 3. effect of nutrient rates on agronomic parameters of the short duration mustard bari sarisha 14 treatments plant height (cm) branches plant-1 (no.) dry weight of stem (g) fresh weight of siliqua (g) dry weight of siliqua (g) t1 =100% npks (stb) 83.53 ab 5.70 bc 20.26 bc 124.52d 23.61 d t2 =t1+ 25% n 82.86 ab 6.03 abc 19.94bc 148.04 b 28.87 b t3 =t1+ 25% np 87.53 ab 5.86 bc 20.24bc 147.44 b 28.03 b t4 =t1+ 25% nk 88.33 ab 5.17 c 20.35 b 137.46 c 25.17cd t5 =t1+ 25% pk 91.00 a 6.73 ab 22.03 b 151.56 b 28.29 b t6 =t1+ 25% npk 91.07 a 7.20 a 25.74 a 180.25 a 33.31 a t7 =75% of t1 79.40 bc 4.83 cd 17.37 c 105.57 e 17.39 e t8 =control 72.68 c 3.92 d 9.72 d 50.24 f 10.23 f cv (%) 6.08 4.71 8.64 3.12 5.15 se 4.19 4.38 1.38 3.32 1.01 means followed by a common letter(s) are not significant at 5% level by of probability fresh weight of siliqua plant-1 the fresh weight of siliquaplant-1at different nutrient levels showed a significant result (table 3). the highest % relative fresh weight of siliqua was observed in t6 (180.25 g plant-1) where 100% recommended dose of fertilizer and an additional 25% npk were used which is statistically different from all other treatments. in contrast, the lowest value of siliqua fresh weight (50.24 g plant-1) was found in t8 treatment. the results indicated that siliqua fresh weight increased in t6 treatment, due to the higher amount of supplied nutrients which might encourage the photosynthesis rate. similar outcomes were obtained earlier by bhagawanet al. (1996) and mondalet al. (1997). dry weight of siliquaplant-1 it is proved from the results that different nutrition has a significant effect on the siliqua dry weight per plant. in table 3it observed that the highest siliqua dry weight (33.31 g) was observed in t6 treatment which is statistically different from all other treatments and t8 showedthe lowest siliqua dry weight (10.23 g). the possible reason might be that due to less in nutrient level lessen the photosynthesis rate of the plant also decreases resulting in less accumulation of photosynthates and ultimately giving the lowest siliqua dry weight in t8 treatment. number of siliquaeplant-1 the number of siliquae plant-1 is one of the most important yield contributing characters in mustard. the number of siliquaplant-1was significantly affected by different levels of fertilizers (table 4). the higher number of total siliquaplant-1(80.87) was recorded with plants grown under t6 treatment which is statistically different fromall other treatments. in contrast, the lower number of total siliqua plant-1 (38.67) was recorded in plants grown under t8 treatment. this might be since nitrogen in the presence of other nutrients plays a vital role in both cell division and cell enlargement which might occur in this study. the results confirmed the findings of singh et al. (1985). 136 ahmed et al. seeds siliqua-1 the effect of different levels of nutrition on the number of seeds siliqua-1 was statistically significant (table 4). the highest number of seeds siliqua-1 (35.90) was obtained from the treatment t6 that statistically similar toall treatments except t4, t5,and t8. the lowest number of seeds seliqua-1 (29.60) was obtained from the t8treatment. additional nitrogen in the presence of other nutrients increased the leaves area which leads to higher total photosynthesis and higher translocation of assimilating from vegetative to reproductive part. these results were in alignment with shuklaet al. (2002)who found that increased fertility levels increased seedspersiliqua. table 4. effect of nutrient rates on yield attributes and stover yield of mustard var. bari sarisha-14 treatment siliquaeplant-1 (no.) seeds siliqua1(no.) 100-siliqua weight (g) 1000-seed weight (g) stover yield (t ha-1) t1=100% npks (stb) 70.20 b 32.60abc 22.67 bc 2.98 a 2.40 d t2 =t1+ 25% n 66.20b 33.76 ab 21.67 bc 2.96 a 2.55 c t3 =t1+ 25% np 71.33b 32.20abc 23.33 b 3.12 a 2.40 d t4 =t1+ 25% nk 56.13c 29.77 c 25.67 ab 2.94 a 2.31 e t5 =t1+ 25% pk 62.07bc 32.17bc 25.67 ab 2.92 a 2.62 b t6 =t1+ 25% npk 80.87 a 35.90 a 26.67 a 3.16 a 2.96 a t7 =75% of t1 55.80 c 32.60abc 21.33 c 2.82 ab 2.10 f t8 =control 38.67 d 29.60c 21.00 c 2.52 b 1.40 g cv (%) 4.71 6.58 5.04 5.89 11.62 se(0.05) 4.38 1.73 0.06 4.57 2.67 means followed by a common letter(s) are not significant at 5% level by of probability siliqua weight different treatments showed significant variation in respect of 100-siliqua weight (table 4). the maximum 100-siliqua weight (26.67 g) was observed in the case of t6 treatment where more nutrition was added and which is statistically similar tot4 and t5 treatments but different from all other treatments. the lowest 100-siliqua weight (21.0 g)was observed in t8 treatment. these results confirmed with the findings of hossainet al. (1997). seed weight it is noted that 1000-seed weight was significantly influenced by different levels of nutrients (table 4). the highest 1000-seed weight (3.16 g) was recorded with t6treatment which is statistically similar toall other treatments except t7 and t8 treatment. the lowest 1000-seed weight (2.52 g) was recorded in the control. seed weight is genetically characteristics, however, it was influenced the nutrient rates. the results indicated that the 1000-seed weight of mustard increased with increased nutrient rates.these results were corroborating with findings of singh et al. (1985) who found that 1000-seed weight was increased withthe applicationof additional nutrients. seed yield the data regarding mustard seed yield as influenced by different fertilizer rates (figure 1). the tested fertilizer treatments affected mustard seed yield significantly. the highest mustard seed yield (1.68t ha1) was produced from the treatment t6 where 25% extra npk was added over the 100% stb fertilizer rate. this yield value was statistically higher than all other treatments except thet3 treatment which was statistically similar. the native nutrient treatment t8produced the lowest mustard seed yield (0.89 t yield and yield attributes of short duration mustard 137 ha-1). due to enhanced growth attributes that crop diverted the photosynthates to reproductive organs for the formation of seeds of large size and number that ultimately increased the yield. these results were in corroborates with those reported by tomaret al. (1997), jagviret al. (2004)and rao et al. (2006). 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 t1 t2 t3 t4 t5 t6 t7 t8 s ee d yi el d (t h a-1 ) n ut ri en t co nt en t (% ) in s ee d treatment nutrient content in seed and seed yield of short duration mustard n p k s seed yield fig. 1. seed yield and nutrient contents in the seedof the short duration mustard var.bari sarisha-14 as influenced by nutrient rates. nutrient content in seed nutrients (n, p, k, and s) content in seedof short duration mustard was significantly affected by the nutrient rates (figure 1). the highest amount of all the nutrients content was found in the treatment t6 that was followed by t3 and t4. the highest amount of n, p, k, and s content in seedof the treatment t6 was 3.75, 0.97, 0.96, and 0.78%, respectively. nutrients content was the lowest in t8 where fertilizers not applied and it was followed by t7 where 25% less amount fertilizers applied from t1 (stb). the lowest amount of n, p, k, and s content in seedof the treatment t8 was 2.50, 0.71, 0.70 and 0.51%, respectively. nutrients content had a harmonic relationship withseedyield. the results revealed that a higher amount of nutrient addition positively influenced to accumulate a higher amount of nutrient in seed. these results confirmed with the findings of yadavet al. (2017). stover yield stover yield of mustard was significantly influenced by the application of different doses of chemical fertilizers (table 4). the higheststover yield (2.96 t ha-1) was recorded in treatment t6 receiving 25% extra npk over the 100% stb fertilizer rate and the lowest stoveryield (1.40 t ha-1) was recorded in t8 treatment. this result was mainly because an optimum fertilizer facilitated maximum utilization of nutrients which enhanced total dry matter production and development of other yield contributing components. the results also confirmed the findings of jagviret al. (2004) which agreed well with the results of the present study. 136 percent increase in yield of grain and stover over control the seed yield of mustard increased significantly due to the increase of seed yield over control (native fertility) ra highest yield increase (88.76 %) showed in t6 treatment receiving 25% extra npk over 100% stb fertilizer rate and the lowest yieldincrease in t7 over the control ranged from 50 to 111.42 %, and the highest stover yield increase was fo treatment (111.42%) and lowest in t7 treatment (50%). fig.2.seed (grain) and stover yield of mustard var. fertilized treatments (t1 to t7) over the controltreatment conclusion in the present study, it showed that the treatment t along with an additional dose of 25% npk) gave the highest seed bari sarisha-14. most of the growth parameters treatment which positively influenced seed and stover yields. sarisha-14 is one of the important crop components mungbean-t.aus-t.aman. the findings concluded that fertilizer dose recommended for attaining better yield of references ali, m.h. and m.j. ullah. 1995. effect of different levels and methods of nitrogen application on growth and yield of rapeseed (brassica campestris l.).ann. bangladesh agri. 5(2): 115 bbs(bangladesh bureau of statistics). 2018. yearbook of agricultural statistics book of bangladesh, ministry of planning, government of people’s republic of bangladesh, dhaka. pp.123-124. bhagawan, s., k.vinod, b. singh and v. kumar. 1996. response of indian mustard ( and sulfur application under rainfed condition. indian j. agron. 41(2): 286 0 10 20 30 40 50 60 70 80 90 100 110 120 t1 t2 t3 yi eld in cr es e ( % ) grain yield increase (%) ahmed et al. over controltreatment yield of mustard increased significantly due to the application of different levels of nutrients. yield over control (native fertility) ranges from 4.49 to 88.76 % (figure 2) and the treatment receiving 25% extra npk over 100% stb 7 treatment.in the case ofstover yield, percent increase and the highest stover yield increase was found in t6 treatment (50%). var. bari sarisha-14 increased (%) in the reatment (t8). onclusion that the treatment t6(100% recommended fertilizers based on soil test gave the highest seed yield of short-duration mustard var. growth parameters and yield components were also higher in this and stover yields. short-duration mustard var. bari components in the four-cropping pattern comprising mustardfindings concluded that an additional 25% npk along withstb yield ofshort-duration mustard variety. references 1995. effect of different levels and methods of nitrogen application on growth and l.).ann. bangladesh agri. 5(2): 115-120. yearbook of agricultural statistics-2017.statistical pocket book of bangladesh, ministry of planning, government of people’s republic of bangladesh, 1996. response of indian mustard (b. juncea) to nitrogen rainfed condition. indian j. agron. 41(2): 286-289. t4 t5 t6 t7treatment grain yield increase (%) stover yield increase (%) yield and yield attributes of short duration mustard 137 bremner, j.m. and c.s. mulvaney.1982. total nitrogen. in: methods of soil analysis, part ii. 2nd ed. amer. soc. agron. inc. usa. pp.595-622. frg (fertilizer recommendation guide). 2018. fertilizer recommendation guide. published by barc, farm gate, dhaka. pp.1-257. gomez, k.a. anda.a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons. inc. new york. usa. pp.97-423. hossain,m.a., m.r. siddique and m.a. siddique. 1997. effect of nitrogen on yield and yield components of some promising varieties of mustard. bangladesh j. agric. 22: 9-15. jagvir, s., d. monga and m.s. deshmuch. 2004. direct and residual effect of sulfur on growth, yield and quality of cotton (gossypiumhirsiutum) and mustard (brassica juuncea) cropping system. j. cotton res. dev. 18(2): 172-174. miah, m.m.u. and z. karim. 1995. extension of integrated plant nutrition system (ipns) at farm level in bangladesh. in. f.j. dent and s. gangwani (eds.) progress and problems in the extension of integrated plant nutrient systems (ipns) at farm level in asia. fao publication no. 12. pp.2942. mondal, p., m. podder, m.a. hossain and m.a. khaleque. 1997. effect of time ofnitrogen application on the yield and yield components of rapeseed. bangladesh j. agril. sci. 2(2): 49-52. rao, k.t., g.j. naidu and g. subbaiah. 2006. effect of foliar application of micronutrient on yield and yield attributes on indian mustard (brassica juuncea l.). agril. sci. digest. 26(2): 144-146. saweda, l.o.l., b.t. omonona, a. sanou andw.o. ogunleye.2017. is increasing inorganic fertilizer use for maize production in ssa aprofitable proposition? evidence from nigeria. food policy. 67:41-51. shukla, r.k., a. kumar,b.s. mahapatra and b.kandpal. 2002. integrated nutrient management practices in relation to morphological and physiological determinants of seed yield in indian mustard (brassica juncea l.). indian j. agric. sci. 72(11): 670-612. singh, s.m., d.r. dahiya and r.p. singh. 1985. effect of varying rectangularities, nitrogen and varieties and yield attributes of mustard. indian j. agron. 30(1): 78-83. tomar, t., s. singh, s. kumar and s.tomar. 1997. response of indian mustard (brassica juncea) to nitrogen, phosphorus and sulfur fertilization. indian j. agron. 42(1): 148-151. yadav, k.g., c. kushwaha,p.k. singh, m. kumar, s.k. yadav and nishant. 2017. effect of nutrient management on yield and nutrient uptake by indian mustard (brassica juncea l). j.pharmaco.phytochem. sp1: 556-559. yamakawa, t. 1992. laboratory methods for soil science and plant nutrition. ipsa, jica project publication no. 2. ipsa, gazipur, bangladesh. yoshida, s., d.a. forno, j.h. cock and k.a. gomez. 1972. laboratory manual for physiological studies of rice. irri, los banos, philippines. table 2.treatment combinations of different nutrients in the experimental field at the central research farm,bari, gazipur bangladesh agron. j. 2019, 22(2): 151-159 integrated nutrient management for sunflower in coastal char land of bangladesh i.s.m. farhad1*, e. jahan2, m.f.a. anik3, m.m.u. chowdhury4 and s. akhter5 1, 3&5soil science division, bari, gazipur, bangladesh 2department of agricultural chemistry, sau, dhaka, bangladesh 4on-farm research division, bari, noakhali, bangladesh *corresponding e-mail: farhadsau@gmail.com (received: 24 march 2020, accepted: 30 april 2020) keywords: sunflower, coastal char land, integrated nutrient management, yield, bcr abstract an experiment was conducted at coastal charlandof ofrd, bari, noakhali;mlt site, amtoli,bargunaand ars,benarpota, satkhira during rabi season of 2018-19to evaluate the effect of integrated nutrient management on growth,yield and economic performance of sunflower. six treatment combinations viz. t1= soil test based fertilizer dose for hyg, t2 = ipns with 5 tha-1cowdung, t3= ipns with 5 tha-1 compost, t4= ipns with 1.5 t ha1vermicompost, t5= farmers’ practice and t6= absolute control were tested. the experiment was laid out in a randomized complete block design with 3 replications and bari sunflower-2 was used as test crop.the ipns treatment combinations are significantly differentfrom rest of the treatments in terms of yield and economic return. application of treatment ipns with 1.5 tha-1vermicompost significantly increased all of the parameters such as the plant height, head diameter, number of seed per head,1000 seed weight, seed yield and stover yield. the significantly highest seed yield (2.19, 2.23 and 2.06 t ha-1 at noakhali, bargunaand satkhira, respectively) was recorded in ipns with 1.5 tha-1vermicompost treated plot (t4) while the lowest seed yield (1.05, 1.10 and 1.02 t ha-1 at noakhali, barguna and satkhira, respectively) was observed in absolute control treatment (t6). salinity level increased at slower rate in t2, t3 and t4, treatments where ipns based nutrient management packages were imposed.during the crop growing period soil salinity ranged from 0.62 to 9.72ds m-1, 0.58 to 9.23ds m-1, 0.73 to 9.86ds m-1 at noakhali, barguna and satkhira, respectively from emergence to maturity stages of the crop. the highest net return (50790 tk. ha-1, 52765 tk. ha-1 and 43940 tk. ha-1 at noakhali, barguna and satkhira, respectively) as well as bcr (1.75, 1.78 and 1.67 atnoakhali, barguna and satkhira, respectively) were obtained from t4 treatment (ipns with 1.5 tha-1vermicompost) whereas the lowest net return (14900 tk. ha-1 ,15175 tk. ha-1 and 11570 tk. ha-1 at noakhali, barguna and satkhira, respectively) and bcr (1.40, 1.33 and 1.26at noakhali, barguna and satkhira, respectively) were obtained from control (t6) treatment. the overall results indicated that ipns with 1.5 tha-1 vermicompostis more effective than other fertilizer management packages in respect of yield as well as economic return for sunflower cultivation in the coastal charland of bangladesh. introduction sunflower (helianthus annuusl.) is an important oilseed crop of the world and it ranks second in production next tosoybean (fao, 2003).it is a thermo neutral crop growing both in rabi and kharifseasons in anywhere in bangladesh. sunflower has potential to reduce the existing gap between production and consumption of edible oil because it contains almost 40-50% oil and rich in protein which is about 23%(rosa and rosemar, 2009). cultivation of sunflower is suitable in the coastal region of bangladesh because of its extensive adaptability and it is a good substitute when it is difficult to cultivate other crops due to climate change, increasing soil salinity in the coastal areas, scarcity of irrigation facility etc.sunflower can be grown in any district of bangladesh and the average production is about 1.2 tha-1, which is relatively encouraging but not satisfactory (bbs, 2016). the lower mailto:farhadsau@gmail.com 152 farhad et al. productivity of sunflower is mainly due to lack of high yielding varieties, its cultivation onmarginal lands with inadequate nutrients and alsocontinuous and imbalance use of inorganic fertilizer deteriorates soil health. experimental evidences revealed that the crop was highly responsive to different fertilizers and the yield could be increased remarkably through judicious fertilization (mohamed, 1984; roy and singh, 2005; kaziet al., 2002). integrated nutrient management practices applied for sunflower can contribute to sustainable growth, yield and quality, influences plant health and reduces environmental risks. use of organic manures with optimum rate of fertilizers under intensive farming system increases the turnover of nutrients in the soil plant system. the organic manures help in reducing the dose of inorganic fertilizer, whichinturn reduces the cost of cultivation and help in improving the soil health. although sunflower cultivation in bangladesh is rather limited, there is an ample scope of increasing its cultivation and productivity through integrated nutrient management. therefore, the present piece of research work was undertaken to know the effect of integration of nutrients for cultivation of sunflower in coastal charlands and to find out the optimum and economic fertilizer dose for sunflower. materials and methods a field experiment was conducted at coastal charlandof ofrd, bari, noakhali (aez-18);mlt site, amtoli,barguna (aez-13) and ars, benarpota, satkhira (aez-13) during rabi season of 2018-19to evaluate the effect of integrated nutrient management for better yield of sunflower. before conducting the experiment, initial composite soil samples (0-15 cm) were collected from the experimental plots and collected samples were analyzed in the laboratory following standard methods (table 1). moreover, nutrient status of vermicompost, compost and cowdung used in the experimental field were also analyzed (table 2). the experiment was laid out in a rcb design with three (03) replicates. the unit plot size was 4m×3m and bari sunflower-2 was used as the test crop. treatments were randomly distributed within the blocks as follows: t1= soil test based fertilizer dose for hyg, t2 = ipns with 5 tha-1cowdung, t3= ipns with 5 tha-1 compost, t4= ipns with 1.5 t ha-1 vermicompost, t5= farmers’ practice and t6= absolute control (table 3a, 3b & 3c). the seeds were sown @ 10 kg ha-1 in line with the spacing of 50 cm x 25 cmon 18 december, 20 december and 17 december, 2018 atnoakhali,barguna and satkhira,respectively. different intercultural operations and plant protection measures were taken as and when necessary to raise healthy crops. table 1. chemical properties of initial soil of experimental field during 2018-19 location ph ec om ca mg k total n p s b cu fe mn zn dsm-1 (%) meq 100g-1 (%) μg g-1 noakhali 6.9 1.05 1.28 5.0 2.3 0.11 0.08 9.3 28.2 0.61 1.01 18 6.74 1.95 barguna 6.5 0.91 1.19 3.7 1.9 0.22 0.09 2.6 22.6 0.50 1.13 21 5.12 1.60 satkhira 7.6 1.13 1.44 1.69 1.1 0.20 0.11 12.1 26.7 0.47 1.18 13 7.68 0.65 critical level 2.0 0.5 0.12 0.12 7/10 10 0.20 0.2 4 1 0.6 ec= electrical conductivity & om= organic matter table 2. nutrient status of compost,cowdung andvermicompost used in the experimental field name of the manure ph oc ca mg k total n p s b zn pb cd as % (ppm) compost 7.1 16.3 1.50 2.10 1.17 1.23 0.79 0.50 0.013 0.14 2.89 2.11 1.72 cow dung 7.5 15.4 2.23 0.44 0.69 1.15 0.57 0.36 0.011 0.15 3.10 2.84 1.26 vermicompost 7.2 17.9 2.10 2.60 1.94 1.68 1.26 0.89 0.015 0.16 2.61 2.19 1.14 oc = organic carbon moisture content of compost = 12.15 %,cowdung = 12.46 % and vermicompost = 11.96 % integrated nutrient management for sunflower 153 table 3a. treatment combinations for sunflower atnoakhali treatments treatment combination chemical fertilizer (kg ha-1) organic manure (t ha-1) n p k s zn b cowdung compost vermicom post t1= soil test based fertilizer dose for hyg (frg,2012) 134 29 56 1.3 0 0 0 t2= ipns with 5 tha1cowdung 111 17.6 42.2 0 5 0 0 t3= ipns with 5 tha1 compost 109.4 11.2 32.6 0 0 5 0 t4= ipns with 1.5 tha-1vermicompost 124 21.4 44.3 0 0 0 1.5 t5= farmers’ practice 138 18 25 0 t6 = absolute control native fertility table 3b. treatment combinations for sunflower at barguna treatments treatment combination chemical fertilizer (kg ha-1) organic manure (t ha-1) n p k s zn b cowdung compost vermicom post t1= soil test based fertilizer dose for hyg (frg,2012) 125 42 31.3 6.9 0 0 0 t2= ipns with 5 tha1cowdung 102 30.6 17.5 0 5 0 0 t3= ipns with 5 tha-1 compost 100 26.2 7.9 0 0 5 0 t4= ipns with 1.5 tha-1vermicompost 114 34 19.6 1.6 0 0 1.5 t5= farmers’ practice 100 20 30 5 t6 = absolute control native fertility the crop was harvested on 28 march, 31 march and 25 march, 2019 at noakhali, barguna and satkhira, respectively. soil salinity level was measured by using electrical conductivity meter adwa (ad 310) at different growth stages of the crop. data were collected on an individual plant basis from ten (10) randomly selected plants of each plot in such a way that the border effect was avoided for high precision. data on yield and yield contributing parameters were recorded and statistically analyzed with the help of statistical package statistix 10 (analytical software. tallahassee, fla, usa) and mean separation was tested by duncan’s multiple range test (dmrt) (steel and torrie, 1960). table 3c. treatment combinations for sunfloweratsatkhira 154 farhad et al. treatments treatment combination chemical fertilizer (kg ha-1) organic manure (t ha-1) n p k s zn b cowdung compost vermicom post t1= soil test based fertilizer dose for hyg (frg,2012) 100 23 36 3.1 1.5 0 0 0 t2= ipns with 5 tha1cowdung 77 11.6 22.2 0 5 0 0 t3= ipns with 5 tha1 compost 75.4 7.2 12.6 0 0 5 0 t4= ipns with 1.5 tha-1vermicompost 89 15.9 24.3 0 0.5 0 0 1.5 t5= farmers’ practice 115 20 25 2 t6 = absolute control native fertility methods of chemical analysis soil ph was measured by a combined glass calomel electrode (jackson, 1958). organic carbon was determined by wet oxidation method (walkley and black, 1934). total n was determined by modified kjeldahl method. ca and mg were determined by nh4oac extraction method. k, cu, fe, mn and zn were determined by dtpaextraction followed by aas reading. boron was determined by cacl2 extraction method. phosphorus was determined by bray and kurtz method (acid soils) and modified olsen method (neutral + calcareous soils). s was determined by cah4 (po4)2.h2o extraction followed by turbidimetric method with bacl2. results and discussion yield and yield components the effect of integrated nutrient management on the yield and yield parameters of sunflower are summarized in the table 4, 5&6. seed yield, stoveryield and yield attributes like plant height, head diameter, number of seeds head-1 and thousand seed weight of sunflower were significantly influenced by different nutrient management packages in this study. table 4. effect of integrated nutrient management on yield and yield contributing characters of sunflower var. bari sunflower-2 at noakhali during rabi season of 2018-19 treatments plant height (cm) head diameter(cm) number of seeds head-1 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) t1 127.6c 14.5bc 547d 57.7abc 1.59c 3.38c t2 131.4b 15.1ab 599c 59.6ab 1.87b 3.80b t3 134.7ab 15.8ab 632b 60.3ab 2.08ab 4.05a t4 136.3a 16.3a 648a 62.2a 2.19a 4.20a t5 123.2cd 13.7c 528d 57.1bc 1.48c 2.97d t6 114.8d 12.2d 463e 54.3c 1.05d 2.35e cv (%) 5.42 4.12 4.60 2.13 6.81 5.14 means followed by same letter (s) do not differ significantly at 5% level of significance t1= soil test based fertilizer dose for hyg (frg,2018),t2= ipns with 5 tha-1cowdung, t3= ipns with 5 tha1compost, t4= ipns with 1.5 tha-1vermicompost,t5= farmers’ practice and t6 = absolute control integrated nutrient management for sunflower 155 significantly the highest plant height (136.3 cm, 137.4 cm and 129.5 cm at noakhali, bargunaand satkhira, respectively) was observed in t4 treatment (ipns with 1.5 t ha-1 vermicompost) which was statistically identical with t3 treatment. the lowest plant height (114.8 cm, 115.5 cm and 112.1 cm noakhali, bargunaand satkhira, respectively) was obtained from absolute control treatment (t6). the result related to plant height was similar to the findings of vedpathak and chavan (2016) who observed that application of vermicompost along with chemical fertilizers increased plant height significantly in sunflower. significantly the maximum head diameter (16.3 cm, 16.5 cm and 15.8 cm at noakhali, barguna and satkhira, respectively) was recorded in ipns with 1.5 t ha-1 vermicompost treated plot (t4) whereas the minimum head diameter (12.2 cm, 12.6 cm and 11.9 cm at noakhali, barguna and satkhira, respectively) was observed in absolute control treatment (t6). table 5. effect of integrated nutrient management on yield and yield contributing characters of sunflower var. bari sunflower-2 at bargunaduring rabi season of 2018-19 treatments plant height (cm) head diameter (cm) number of seeds head-1 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) t1 127.1c 14.6d 556d 58.7c 1.66cd 3.54d t2 132.6b 15.7c 602c 59.3bc 1.89bc 3.83c t3 135.3ab 16.1b 625b 61.5ab 2.12ab 4.16b t4 137.4a 16.5a 656a 62.4a 2.23a 4.35a t5 125.2c 13.5e 534e 57.6c 1.56d 3.06e t6 115.5d 12.6f 469f 55.8d 1.10e 2.47f cv (%) 5.61 4.23 5.87 2.94 7.24 6.12 means followed by same letter (s) do not differ significantly at 5% level of significance t1= soil test based fertilizer dose for hyg (frg, 2018), t2= ipns with 5 tha-1cowdung,t3= ipns with 5 tha-1 compost,t4= ipns with 1.5 tha-1vermicompost,t5= farmers’practice and t6 = absolute control table 6.effect of integrated nutrient management on yield and yield contributing characters of sunflower var. bari sunflower-2 at satkhira during rabi season of 2018-19 treatments plant height (cm) head diameter (cm) number of seeds head-1 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) t1 120.8c 14.1ab 546d 54.1bc 1.52c 3.01c t2 124.4b 14.7ab 589c 56.6ab 1.80b 3.34b t3 127.3a 15.2ab 617b 58.3a 1.97ab 3.65a t4 129.5a 15.8a 639a 59.2a 2.06a 3.73a t5 117.6d 13.3bc 501e 53.5bc 1.37d 2.76d t6 112.1e 11.9c 443f 51.1c 1.02e 2.11e cv (%) 4.87 4.14 3.85 3.40 7.35 7.72 means followed by same letter (s) do not differ significantly at 5% level of significance t1= soil test based fertilizer dose for hyg (frg, 2018), t2= ipns with 5 tha-1cowdung,t3= ipns with 5 tha-1 compost,t4= ipns with 1.5 tha-1vermicompost,t5= farmers’practice and t6 = absolute control significantly the highest number of seeds head-1 (648, 656 and 639 at noakhali, barguna and satkhira, respectively) was observed in t4 treatment which was followed by t3, t2, t1 and t5 treatment whereas the lowest number of seeds head-1 (463, 469 and 443 at noakhali, barguna and satkhira, respectively) was obtained from absolute control treatment (t6). significantly the maximum 1000 seed weight (62.2 g, 62.4 g and 59.2 g at noakhali, barguna and satkhira, respectively) was recorded in t4 treatment 156 farhad et al. which was statistically at par with t3 and t2 treatments whereas the minimum 1000 seed weight (54.3 g, 55.8 g and 51.1 g at noakhali, barguna and satkhira, respectively) was recorded in control treatment (t6).significantly the highest seed yield (2.19 t ha-1, 2.23 t ha-1 and 2.06 t ha-1 at noakhali, barguna and satkhira, respectively) was recorded in ipns with 1.5 t ha-1 vermicompost treated plot (t4) which was statistically at par with t3 (ipns with 5 t ha-1 compost) treatment the lowest seed yield (1.05 t ha-1, 1.10 t ha-1 and 1.02 t ha-1 at noakhali, barguna and satkhira, respectively) was observed from absolute control treatment (t6). the result was similar to the findings of kalaiyarasan and vaiapuri (2008) who observed that integrated use of chemical fertilizers along with vermicompost gave maximum seed yield in sunflower. the highest stover yield (4.20 t ha-1, 4.35 t ha-1 and 3.73 t ha-1 at noakhali, barguna and satkhira, respectively) was recorded in ipns with 1.5 t ha-1 vermicompost treated plot (t4) whereas the lowest stover yield (2.35 t ha-1, 2.47 t ha-1 and 2.11 t ha-1 at noakhali, barguna and satkhira, respectively) was observed from absolute control treatment (t6). soil salinity soil salinity level gradually increased from emergence to maturity stages of the crop (table 7). initial salinity level was more or less same among the treatments. salinity level increased at slower rate in t2, t3 and t4 treatments where ipns based nutrient management packages were imposed.itmay be due to the fact that any kind of organic matter will release organic acids upon decaying.so acid will result into lowering of ph.the decrease in ph can lead to charging of clay minerals and electrostatic adsorption of the organic compounds.so all kinds of organic materials shall be definitely reducing soil salinity.moreover, the use of organic matter improves the soil structure and permeability. table 7. changes in soil salinity of sunflower field as influenced by various treatment combinations at different growth stages at noakhali, bargunaand satkhira during rabi season of 2018-19 treatment emergence stage vegetative stage flowering stage seed formation stage maturity stage salinity range (ds m-1) at noakhali t1 0.76-1.97 1.75-3.61 2.47-5.27 4.50-7.00 6.75-9.41 t2 0.62-1.75 1.64-2.90 2.38-4.10 3.72-5.54 5.11-7.90 t3 0.69-1.85 1.59-2.97 1.98-3.91 3.27-5.12 4.68-7.35 t4 0.71-1.79 1.60-2.81 2.23-3.98 3.57-5.33 4.76-7.41 t5 0.65-1.89 1.68-3.50 2.49-5.17 4.80-6.96 6.94-9.67 t6 0.71-2.10 2.11-3.92 2.82-5.89 4.92-7.71 7.15-9.72 at barguna t1 0.69-1.85 1.52-2.90 2.41-4.89 4.66-6.26 5.94-8.85 t2 0.58-1.71 1.40-2.41 2.32-3.84 3.61-5.10 4.30-7.10 t3 0.63-1.80 1.32-2.10 1.87-3.78 2.49-5.79 4.12-6.35 t4 0.59-1.82 1.30-2.32 2.20-3.82 2.85-5.81 4.39-6.24 t5 0.72-1.91 1.63-3.22 2.50-5.19 4.71-7.10 5.98-9.10 t6 0.66-1.86 1.70-3.43 2.63-5.32 4.78-7.12 6.13-9.23 at satkhira t1 0.86-2.14 1.70-3.61 3.25-5.75 4.92-7.20 6.70-9.34 t2 0.95-2.10 1.67-3.10 2.36-4.10 3.87-6.79 5.17-8.30 t3 0.82-1.76 1.62-2.98 2.82-4.70 3.40-6.52 5.10-7.95 t4 0.73-1.98 1.56-2.87 2.19-3.92 3.72-6.80 4.92-7.62 t5 0.81-2.23 1.81-3.70 2.95-5.48 4.62-8.20 7.11-9.74 t6 0.80-2.29 2.15-4.10 3.67-6.89 5.14-9.17 7.20-9.86 integrated nutrient management for sunflower 157 t1= soil test based fertilizer dose for hyg (frg,2012),t2= ipns with 5 tha-1cowdung,t3= ipns with 5 tha-1 compost,t4= ipns with 1.5 tha-1vermicompost,t5= farmers’ practice and t6 = absolute control this enhances leaching of salt, reduces surface evaporation, and inhibits salt accumulation in the surface layers. in addition, organic matter also increases water infiltration, water-holding capacity, and aggregate stability and reduces electrical conductivity (qadiret al., 2001). on the other hand, salinity level increased at higher rate in t6 treatment followed by t5 and t1. during the crop growing period soil salinity ranged from 0.62 to 9.72 ds m-1, 0.58 to 9.23 ds m-1, 0.73 to 9.86 ds m-1 at noakhali, barguna and satkhira, respectively from emergence to maturity stages of the crop. cost and return analysis cost and return of sunflower as influenced by different nutrient management packages have been shown in the table 8, 9&10. among the treatments, the highest gross return (117900 tk. ha-1, 120200 tk. ha-1 and 110460 tk. ha-1at noakhali, barguna and satkhira, respectively), net return (50790 tk. ha1, 52765 tk. ha-1 and 43940 tk. ha-1 at noakhali, bargunaand satkhira, respectively) as well as bcr (1.75, 1.78 and 1.67 at noakhali, barguna and satkhira, respectively) were obtained from t4 treatment (ipns with 1.5 tha-1 vermicompost) whereas the lowest gross return (57200 tk. ha-1 , 59940 tk. ha-1 and 55220 tk. ha-1at noakhali, barguna and satkhira, respectively), net return (14900 tk. ha-1, 15175 tk. ha-1 and 11570 tk. ha-1 at noakhali, barguna and satkhira, respectively) and bcr (1.40, 1.33 and 1.26 at noakhali, barguna and satkhira, respectively) were obtained from control (t6) treatment. table 8.cost and return analysis of bari sunflower-2 as influenced by integrated nutrientmanagement atnoakhali during 2018-19 treatments yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) net return (tk. ha-1) bcr seed stover t1 1.59 3.38 86340 57200 29140 1.50 t2 1.87 3.80 101100 64109 36991 1.57 t3 2.08 4.05 112100 70970 41130 1.58 t4 2.19 4.20 117900 67110 50790 1.75 t5 1.48 2.97 79940 50550 29390 1.43 t6 1.05 2.35 57200 42300 14900 1.40 t1= soil test based fertilizer dose for hyg (frg,2012),t2= ipns with 5 tha-1cowdung,t3= ipns with 5 tha-1 compost, t4= ipns with 1.5 tha-1vermicompost,t5= farmers’ practice and t6 = absolute control input and output price per kg: sunflower seed = tk. 70, urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, vermicompost = tk. 12, compost = tk. 5, cowdung= tk.3, sunflower = tk. 50 and stover = tk. 2 table 9.cost and return analysis of bari sunflower-2 as influenced by integrated nutrient management atbarguna during 2018-19 treatments yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) net return (tk. ha-1) bcr seed stover t1 1.66 3.54 90100 57177 32923 1.57 t2 1.89 3.83 102160 62213 39947 1.64 t3 2.12 4.16 114320 69370 44950 1.65 t4 2.23 4.35 120200 67435 52765 1.78 t5 1.56 3.06 84120 54842 29278 1.53 t6 1.10 2.47 59940 44765 15175 1.33 t1= soil test based fertilizer dose for hyg (frg,2012),t2= ipns with 5 tha-1cowdung,t3= ipns with 5 tha-1 compost,t4= ipns with 1.5 tha-1vermicompost,t5= farmers’ practice and t6 = absolute control 158 farhad et al. input and output price per kg:sunflower seed = tk. 70, urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, vermicompost = tk. 12, compost = tk. 5, cowdung= tk.3, sunflower = tk. 50 and stover= tk. 2 table 10.cost and return analysis of bari sunflower-2 as influenced by integrated nutrient management at satkhira during 2018-19 treatment yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) net return (tk. ha-1) bcr seed stover t1 1.52 3.01 82020 55177 26843 1.48 t2 1.80 3.34 96680 60120 36560 1.60 t3 1.97 3.65 105800 67424 38376 1.56 t4 2.06 3.73 110460 66520 43940 1.67 t5 1.37 2.76 74020 52842 21178 1.40 t6 1.02 2.11 55220 43650 11570 1.26 t1= soil test based fertilizer dose for hyg (frg, 2012), t2= ipns with 5 t ha-1 cowdung, t3= ipns with 5 t ha-1 compost, t4= ipns with 1.5 t ha-1 vermicompost, t5= farmers’ practice and t6 = absolute control input and output price per kg: sunflower seed = tk.70, urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, zinc sulphate =tk. 150, boric acid = tk.220,vermicompost = tk. 12, compost = tk. 5, cowdung= tk. 3, sunflower = tk. 50 and stover = tk. 2 conclusion based on the results, it may be concluded that ipns with 1.5 tha-1vermicompostis superior to the other fertilizer management packages in respect of yield as well as economic return for sunflower cultivation in the coastal char land of bangladesh. references bbs (bangladesh bureau of statistics). 2016. the year book of agricultural statistics of bangladesh. statistics division, ministry of planning, government of the people’s republic bangladesh, dhaka.p.39. fao.2003.production year book. food and agriculture organization, rome, italy. 57:122. jackson, m.l. 1958. soil chemical analysis . prentice hall inc. engle-wood, cliffs, n.y. kalaiyarasan, c.and v. vaiyapuri.2008. effect of integrated nutrient management practices on seed yield and quality characters of sunflower (helianthus annus l.). intl.j. agric. sci.4:231-233. kazi, b.r., f.c. oad and a. lakho. 2002. effect of irrigation frequencies on growth and yield of soybean. pakistan j.appl. sci. 2: 661-662. mohamed, s.a. 1984. effect of irrigation water and fertilization on yield and water use efficiency of corn plants in fayoum governorate, moshtohor, egypt. ann.agril.sci. 20:221-235. qadir, m., s. schubert, a. ghafoor and g. murtaza. 2001. amelioration strategies for sodic soils: a review. land degrad. dev. 12: 357–386. rosa, p.and a.rosemar.2009. chemical composition of brazilian sunflower varieties. helia. 32: 145-155. 10.2298/hel0950145r. roy, r.k. and k.s.p. singh.2005.response of popcorn (zea mays) to plant population and nitrogen.indianj.agron.31: 87-92. steel, r.g.d. and j.h.torrie.1960.principles and procedures of statistics with special reference to the biological sciences. mcgraw hill, new york, pp.187-287. vedpathak, m.m. and b.l.chavan. 2016. studies on impact of organic and chemical fertilizers on growth and yield of sunflower(helianthus annus l.). j. res. 2(10):46-51. integrated nutrient management for sunflower 159 walkley, a. and i.a. black. 1934. an examination of the degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. soil sci. 37: 29-38. based on the results, it may be concluded that ipns with 1.5 tha-1vermicompostis superior to the other fertilizer management packages in respect of yield as well as economic return for sunflower cultivation in the coastal char land of bangladesh. bangladesh agron. j. 2019, 22(2): 67-75 effect of different tillage options and residue retention for sustainable crop production in wheatmungbean-rice cropping pattern in dry areas m.i. hossain1, m.i. hossain2, m.a. ohab3, m.h.r. sheikh4 and b.l. nag5 1principal scientific officer, regional station, bwmri, rajshahi, 2director general, bwmri, nashipur, dinajpur, 3&4director (planning) & director (research), bari, gazipur corresponding e-mail: iliasrwrc@gmail.com (received: 29 december 2019, accepted: 18 april 2020) keywords:conservation agriculture, productivity, soil fertility, sustainable and long term effect abstract the study was conducted to know the productivity and soil fertility status of intensified rice-wheat (rw) systems by adding a third pre-rice crop mungbeani.ewheat-mungbeanrice cropping pattern. the trial comprises five packages of practices including crop residue retention, seeding methods with tillage options imposed on the component crops in the same cropping pattern. the results indicated that keeping standing 30% crop residue in the field with minimum disturbance of soil had significant contribution on grain yield of wheat-mungbean-rice sequence compare to conventional practice of well-till without crop residue retention. system productivity and fertility were evaluated under five levels of tillage options (zero, strip, raised bed, minimum tillage by power tiller operated system (ptos) and conventional tillage practice (ctp) in a rwm cropping pattern. both permanent raised bed and strip till with 30% straw retention produced the highest productivity in all years and the lowest yield was also found from conventional practice with 30% straw retention.soil organic matter in surface soil had increased by 0.12% after 3years crop cycles with 30% sr from rice and wheat and full residue retention from mungbean crop. straw retention is an important component of soil management and may have long term positive impacts on soil quality. the combination of raised bedsystems and strip tillage with 30% residues retained appears to be a very promising technology for sustainable intensification of wheat-mungbean-rice croppingpattern in dry zone areas. introduction resource conserving technologies (rct) are being introduced to the farmers and they are showing interest to grow crop with rct because, it reduces cultivation cost, protects degradation of soil and saves water without yield sacrifice. zero-till, bed planting, strip tillage and minimum tillage by power tiller operated seeder (ptos) with residue retention are known as resource conservation technology (rct). rct also offers the opportunity to plant wheat timely (laurenet al., 2006). delayed wheat planting reduces yield @ 1.3% per day after november 30. connor et al. (2002) suggested that permanent raised beds might offer farmers further significant advantages such as increased opportunities for crop diversification, mechanical weeding and placement of fertilizers. however, for getting expected crop yields with rct a full package of production technologies especially fertilizer management should be included. although the non-rice season across the rice-wheat area with low rainfall, heavy pre-monsoonal rain can cause disastrous effects on the third crop, like maize or mungbean grown after wheat or before rice, both during establishment and grain filling stagedue to water logging (timsina and connor, 2001; quayyumet al., 2002). broadcasting fertilizer enhances losses of fertilizer and reduces fertilizer use efficiency in rct tillage options especially in zero-till and 72 hossain et al. bed planting practices. on the other hand, there are many evidences that residue retention have significant contribution on crop productivity and soil fertility with sustainable way. growing maize crops in a cropping system is beneficial not only for economic products but also for soil amelioration (singh,2003). the research work on residue management with rct is not done on large scale in our country. so, in the experiment it was tried to find out the sustainable yield from the pattern wheatmonsoon riceby introducing third crop mungbean after wheat and to improve soil fertility and productivity. materials and methods a rabi season wheat (triticumaestivum)-kharif 1 mungbean (vignaradiata)-monsoon rice(oryza sativa) cropping pattern was started instead of wheat-monsoon rice pattern with wheat sown in november 24, 2015 at the regional wheat research centre, shyampur, rajshahi, bangladesh (24o3'n, 88041e, 18 m above sea level). the site has a subtropical climate and is located in bangladesh agro ecological zone 11 (high ganges river flood plan) on flood-free high land, with coarse-textured, highly permeable soil (barc, 2012). the area generally receives 1072 mm mean annual rainfall, about 95% of which occurs from may to september. total rainfall was the highest during the monsoon rice season and lowest in the wheat season in all years. sometime maximum temperature was above 38400c in the month of may and minimum temperature was below 3-50c in the month of january. sunshine hours were maximum during the month from november to march in every all year (figure 1). fig. 1. weekly weather parameters from all crop season. the trial involved a three-crop sequence i, e., rice-wheat-mungbean (rwm) planted on zero, tillage, strip tillage, and permanent raised bed, minimum tillage and conventional practices. rice was transplanted (one 25-days-old seedling per hill) with spacing 30 cmx 15 cm spacing in late july and harvested in late november by manual. wheat was seeded with 100-120 kg seed ha-1withfive tillage like zero tillage, strip tillage, permanent raised bed, minimum tillage and conventional practice, respectively, in late november and harvested in late march. after harvest of wheat, mungbean was sown in early april with seeding rate of 35 kg ha-1 and harvested in mid-july for zero tillage, strip tillage, permanent raised bed, minimum tillage and conventional practices. the trial was established in 0 10 20 30 40 50 60 1n ov -1 6 8n ov -1 6 15 -n ov -1 6 22 -n ov -1 6 29 -n ov -1 6 6d ec -1 6 13 -d ec -1 6 20 -d ec -1 6 27 -d ec -1 6 3ja n17 10 -ja n17 17 -ja n17 24 -ja n17 31 -ja n17 7fe b17 14 -f eb -1 7 21 -f eb -1 7 28 -f eb -1 7 7m ar -1 7 14 -m ar -1 7 21 -m ar -1 7 28 -m ar -1 7 4ap r-1 7 11 -a pr -1 7 18 -a pr -1 7 rf(mm) t max(0c) tmin(0c) sh (hr) effect of different tillage options and residue retention for sustainable crop production 73 the treatments of five tillage options with 30% straw (1.5 t ha-1) management practices. the area of each subplot was 15 m2 (5m x 3m) with three replications. after planting the wheat or rice, straw from the preceding cereal crops was returned as mulch into the plot from which it had been removed at harvest. after harvesting and threshing, the rice and wheat straw were returned without chopping as standing way. the width of the beds was 60 cm (furrow to furrow) and the depth of the furrows on average was 15 cm. two rows of wheat (var. bari gom-30) or rice (var. brri dhan71) with a spacing of 30 cm, were planted by hand sowing on each tillage options, two rows of rice on zero tillage, strip tillage, permanent raised bed, minimum tillage and conventional method, mungbean (var. bari mung-6) was sown by tillage machineries in the furrows and indicator plant to assess microbial activity in the soil environment. the mungbean was harvested about 60 days after sowing (das). in case of conventional tillage practices (ctp), wheat was sown in 20 cm, mungbeanwassown in 30 cm and rice was transplanted in 30 cm x 15 cm spacing. a basal dose of p (20, 22 and 26 kgha-1) from triple super phosphate, k (15, 35 and 33 kgha-1) from muriate of potash and s (10, 11 and 20 kgha-1) from gypsum was applied to mungbean, rice and wheat, respectively. in rice, the entire amount of pks was broadcast before transplanting and mulching on zero tillage, strip tillage, permanent raised bed, minimum tillage and conventional tillage practice (ctp). for ctp the fertilizer was broadcast before tillage as is the usual practice. the recommended rate of n (80 kgha-1 for rice, 100 kgha-1 for wheat and 20 kgha-1 for mungbean) was applied as urea. for mungbean all n was applied before seeding. with ctp, n was applied in broadcast, while with beds it was banded on top of the soil between two rows in three equal installments 15, 30 and 45 days after seeding, while wheat, two-thirds of the n was applied before seeding and the remaining one-third at crown root initiation (cri) stage. sufficient irrigation water was applied to fill the furrows of all tillage options.flood irrigation was applied in conventional plots. weed control was done after the first irrigation for wheat by affinity application @ 2 glitre-1 of water, and at 25 and 45 days after transplanting for rice by ronstar @ 1mllitre-1 of water. it is important to note that there was no additional weeding where outbreaks occurred-the treatments were compared with the same level of weed management. grain and straw yield were determined on a whole plot basis or 15 m2 areas in each plot. statistical analysis of data the data were analyzed statistically following computer package mstatc and the significance of mean differences was adjudged by duncan’s multiple range test (dmrt) at p ≤ 0.05 (gomez and gomez, 1984). result and discussion before experimentation initial soil sample (before 1st crop) was collected and analyzed to know the nutrient status and the results were presented in table 1. the soil was slightly alkaline (7.8 ph) having low organic matter content (0.94%) and the total n & boron content was very low (0.05% & 0.27 µg). the overall soil fertility status was low. table 1. fertility status of initial soil sample of the experimental site at rwrc, bari, rajshahi before started the experiment sample ph om (%) total n (%) k p s zn b meq100g-1 µg g-1 value 7.8 0.94 0.05 0.21 10 23.3 0.14 0.27 critical level 0.12 0.12 10 10.0 0.60 0.20 72 hossain et al. interpretation slightly alkaline very low very low medium low opt. very low very low grain yield and yield components of wheat yield and yield components data were shown in table 2. tillage systems with straw retention had significant influenced on grain yield and yield components except spike m-2 and spikeletspike-1. the maximum average grain yield 4.39 t ha-1 from raised bed systems with 30% straw retention and same yield were also found from strip till method 4.28 t ha-1. the lowest yield 3.79 t ha-1was also found from conventional tillage with 30% straw retention. grain yield was higher due to higher yield attributes. laurenet al. (2006) got higher yield from both permanent bed and strip till method. the minimum yield (3.79 t ha-1) was found from conventional tillage practice due to lower yield components.kataki (2001) found similar findings from both tillage options in wheat. yield components like spike m-2 and spikelet spike-1 did not get any significant effect on different tillage options but other attributes like grains spike-1and thousand grain weight (tgw) were also significant effect on tillage options with straw retention. maximum grains spike-1 was found from raised bed system and at par with strip tillage method and minimum grains spike-1 was also found from conventional tillage. sayre et al.(2005) found maximum yield components from residue retention with raised bed and strip till method. table 2.yield and yield components of wheat as influenced by different tillage options and strawretention in 2015-16 to 2016-17 tillage options x straw retention spikes m-2 (no.) spikelet spike-1 (no.) grains spike-1 (no.) tgw (g) grain yield (t ha-1) 2015-16 2016-17 average conv. x 30% straw 322 17.7 48.3 52.4 3.73 3.85 3.79 xerox 30% straw 317 18.3 49.2 53.6 4.08 4.19 4.14 strip x 30% straw 319 18.5 50.3 53.8 4.24 4.32 4.28 bed x 30% straw 312 18.6 51.4 54.2 4.36 4.41 4.39 ptos x 30% straw 325 18.2 49.8 52.8 4.04 4.02 4.03 cv (%) 9.76 6.85 8.45 5.75 10.25 7.65 lsd(0.05) ns ns 1.325 1.024 0.245 0.413 plant height and biomass production ofmungbean crop both biomass productions and plant height were significantly influence under different tillage options with 30% straw retention table 3). the higher plant height (77.4 cm) from raised bed with 30% straw retention and it was at par with zero tillage with 30% straw retention. maximum fresh biomass weight (20.2 t ha-1) was found from raised bed tillage system followed by zero tillage (19.3 t ha-1) and strip till method. the two years average oven dry biomass yield (3.85t ha-1) was also found from raised bed system and it were zero (3.76 t ha-1) and strip till (3.62t ha-1) method. sayre et al. (2005) found similar findings from their experiments under permanent and zero tillage system. table 3.plant height and freshbiomass at 40 das with two years dry biomassproduction at finalharvest of mungbeanat different tillage options with straw retentionin 2015-16 and 2016-17 tillage options plant height (cm) fresh biomass yield (t ha-1) dry biomass yield (tha-1) 2015-16 2016-17 average zero tillage 76.3 19.3 3.72 3.80 3.76 strip tillage 72.6 18.5 3.58 3.66 3.62 raised bed 77.4 20.2 3.77 3.93 3.85 effect of different tillage options and residue retention for sustainable crop production 73 minimum tillage 73.5 17.2 3.43 3.53 3.48 conventional 68.2 16.4 3.27 3.37 3.32 lsd(0.05) 5.75 1.112 0.348 0.360 cv (%) 14.52 10.56 10.35 10.23 despite lower grain yields were also found from zero tillage mungbean always produced higher biomass with taller plants than in conventional tillage and followed by raised bed systems. it might be an indirect benefit for soil in zero tillage and raised bed planting methods. for excessive vegetative growth in mungbean in zero tillage might reduce the grain yields. lemon ortega et al. (2004) found maximum biomass from raised bed and zero tillage systems. seed yield and yield components of mungbean conservation agriculture influenced by different characters of mungbean. consequently, pod plant-1, seeds pod-1, 1000 seed weight and seed yield were influenced significantly whereas plants m-2 was statistically insignificant (table 4). the maximum pods plant-1 was recorded in raised bed with 30% straw retention (22.3) which was statistically identical with that of strip and minimum tillage with 30% straw retention. talukderet al. (2004) found maximum munbean yield from both raised bed and strip till method.the minimum pods plant-1 was found from conventional with 30% straw retention. similarly, maximum seedspod-1, 1000 seed weight and seed yield were recorded from both raised bed and strip till with 30% straw retention. this might be due to border effect with more uptakes of nutrients. 26% yield increased from raised bed with 30% straw retention and it was identical of strip and minimum tillage. zero tillage did not give higher yield increase but it was higher from conventional with 30% straw retention.talukderet al. (2006) found more pods plant-1 and seeds pod1from both permanent and strip tillage systems. table 4.average two years yield and yield components of mungbean as influenced by different tillage options and straw retention from 2015-16 and 2016-17 tillage options x straw retention plant stands m-2 (no.) pods plant-1 (no.) seeds pod-1 (no.) tsw (g) av. two years seed yield (tha-1) (%) yield increase over conv. conv. x 30% straw 38.5 17.8 7.87 50.8 1.02 zero x 30% straw 37.8 18.5 8.70 51.2 1.12 8.0 strip x 30% straw 39.2 21.7 9.12 52.0 1.25 18.0 bed x 30% straw 38.9 22.3 10.24 52.4 1.37 26.0 ptos x 30% straw 39.3 21.4 9.04 50.3 1.21 15.0 cv (%) 11.63 10.42 3.48 2.32 3.47 lsd(0.05) ns 3.24 0.595 0.892 0.213 ns; f-test was not significant grain yield and yield components of t.aman (monsoon) rice conservation agriculture influenced by different characters of t. aman rice. consequently, grains panicle-1 and 1000 grain weight were influenced significantly whereas hill m-2, panicles hill-1 and grain yield were statistically insignificant (table 5). the maximum grains panicle-1(133.8) was recorded in raised bed with 30% straw retention which was statistically identical (127.2 & 124.6) with that of strip and ptos with 30% straw retention. singh et al. (2005) found non-significant effect of rice under different tillage options with residue retention about four years. the minimum grains panicle-1 (122.4) was found from zero tillage with 30% straw retention and it was identical with conventional with 30% straw retention. similarly highest 1000 grain weight (25.2 g) was recorded from both raised bed and strip till (24.8 g) with 30% straw retention. guptaet al.(2002) found similar findings from their experiments. average two years maximum grain yield was recorded (4.53 t ha-1) from raised bed systems and it was identical with that of strip till (4.47 t ha-1) and minimum tillage by ptos (4.41 t ha72 hossain et al. 1) with 30% straw retention. the average minimum grain yield (4.23 t ha-1) from zero tillage option.quayyumet al.(2002) obtained similar results from their experiment. table 5.average two years yield and yield components of t.aman rice as influenced by different tillage options and strawretention from 2015-16 and 2016-17 tillage options x straw retention hill m-2 (no.) panicles hill-1 (no.) grains panicle-1 (no.) tgw (g) grain yield (t ha-1) 2015-16 2016-17 average conv. x 30% straw 28.7 18.1 126.8 23.8 4.26 4.41 4.34 zero x 30% straw 27.5 17.7 122.4 23.7 4.19 4.27 4.23 strip x 30% straw 29.5 19.2 127.2 24.8 4.41 4.53 4.47 bed x 30% straw 29.8 19.4 133.8 25.2 4.43 4.63 4.53 ptos x 30% straw 28.7 18.2 124.6 23.7 4.33 4.49 4.41 cv (%) 9.76 6.85 8.45 5.75 10.87 9.56 lsd(0.05) ns ns 0.325 0.422 ns ns labor requirement and % saved labor for land preparation with seeding or transplanting from three years study both from resource conservation technologies (rcts) and conventional tillage practices, we found from table 6 that conventional tillage required more number of labor for land preparation with seeding and transplanting of wheat and rice seedlings over rcts. connoret al.(2002) found similar findings from same type of tillage experiments. beside this, from figure 2it observed that rcts (zt, bp, st) tillage saved 26-50% labor under land preparation. bed planting, zero tillage and strip tillage saved labor from 50%, 28%, 26%, respectively.katakiet al.(2001) obtained 25-35% labor saving from raised bed and strip tillage systems. table 6. labor requirement and save labor for land preparation and seeding/transplanting of wheat and rice crop tillage options year 1 year 2 year 3 average save labor (person hr-1 ha-1) rcts 376 316 409 367 126 ctp 503 450 526 493 effect of different tillage options and residue retention for sustainable crop production 73 fig.2. saved labor (%) from land preparation with seedingof wheat crop under different tillage options (ct-conventional tillage, zt-zero tillage, bp-bed planting, st-strip tillage). soil properties after 3 years crop cycles both from raised bed and strip tillage options that of soil condition was improved over conventional tillage practice (table 7). soil ph, organic matter content, total n, available p, exchangeable k and mg were found higher in both raised bed and strip tillage options than conventional tillage. after 3 years crop cycles, retention of straw from all three crops in all tillage systems had increased the soil organic matter by 0.08-0.12% over conventional. since the all tillage options produced more biomass in mungbean and higher crop residues were kept in the soil, properties were improved. hobbs et al.(2000) found more biomass in permanent raised bed with straw retention experiments. while some of the increment may have been due to formation of the beds from topsoil, the change in organic c increased as the rate of residue retention increased from 100%, indicating that straw retention also increased organic c on the beds. kumar and goh (2000) reported that, in the longer term, residues and untilled roots from crops can contribute to the formation of som. after three years crop cycles, soil condition in permanent raised bed tillage options was better than conventional tillage. table 7. soil properties analyzed after three years crop cycle tillage options x sr ph organic matter (%) total n (%) available p (µg g-1soil) exchangeable k (meq100g-1 soil) available s (mg g-1 soil) zn (µgg-1 soil) b (µg g-1 soil) conv. x 30% sr 7.9 1.02 0.06 13.3 0.23 23.7 0.15 0.29 zero x 30% sr 8.0 1.04 0.07 13.5 0.25 24.2 0.17 0.31 strip x 30% sr 8.2 1.05 0.07 14.5 0.25 24.8 0.18 0.34 bed x 30% sr 8.1 1.06 0.08 14.2 0.27 24.9 0.19 0.35 ptos x 30% sr 8.2 1.04 0.08 13.8 0.26 24.8 0.18 0.34 conclusion yield and yield component of crops with an intensive wheat-mungbean-rice cropping pattern was achieved more under different tillage options with 30% straw retention over conventional. from two years study it was revealed that raised bed and strip tillage systems with 30% straw retention affected in terms of yield and yield components for all three crops which ultimately produced maximum yield due to its more border effect. soil organic matter in surface soil had increased by 0.12% after two years crop cycles with 30% residue retention from rice, wheat and full residue retention from mungbean crop. residue retention is an important component of soil management and may have long term 0 28 50 26 0 20 40 60 ct zt bp st % saved labor 72 hossain et al. positive impacts on soil quality. both raised bed and strip till systems with 30% residues retained appears to be a very promising technology for sustainable intensification of rice-wheat-mungbean (rwm) systems in dry areas. references barc (bangladesh agricultural research council). fertilizer recommendation guide, 2012. pp.10-12. connor d.j., j. timsina and e. humphreys. 2002. prospects for permanent beds for the rice-wheat system. in: ‘improving the productivity and sustainability of rice-wheat systems: issues and impacts’ (j.k. ladha, j.e. hill, j.m. duxbury, r.k. gupta and r.j. buresh eds.). vol. 65, pp.197-210. asa special publication, asa inc., madison, wi. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research(second edition).john wiley & sons, inc., irri, philippines, 680p. gupta, r.k., r.k. naresh, p.r. hobbs and j.k. ladha. 2002. adopting conservation agriculture in ricewheat systems of the indo-gangetic plainsnew opportunities for saving on water. paper presented at the water wise rice production workshop”, 5-10 april 2002, irri, philippines. hobbs, p.r and r.k gupta. 2000. ‘soil and crop management practices for enhanced productivity of the rice-wheat cropping system in the sichuan province of china’.rice-wheat consortium paper series 9. (rwc, new delhi, india). kataki, p.k. 2001. the rice-wheat cropping system in south: trends, constraints andproductivitya prologue, j. crop prod. 3: 1-26. kumar, k. and k.m. goh. 2000. crop residue management, effects on soil quality, soilnitrogen dynamics, crop yield and nitrogen recovery. adv. agron. 68: 197-319. lauren, j.g., j.m. duxbury, m.i. hossain, g. sah, a.s.m.h.m. talukder and c.a. meisner. 2006. permanent raised bed cultivation improves nitrogen and water use in rice-wheat cropping systems of south asia. 1st world science congress, usa. lemon-ortega, a.l., k.d. sayre and c.a. francis. 2004. wheat and maize yields in responseto straw management and nitrogen under a bed planting system. agron. j. 92: 295-302. quayyum, m.a., j. timsina, m.a.h.s. jahan, r.a. begum and d.j. connor. 2002. grain yield and system productivity for wheat-mungbean-rice and wheat-maize rice sequences in northern bangladesh. thai j. agric. sci. 35: 51-62. sayre, k.d., a. limon and b. govaerts. 2005. experiences with permanent bed planting systems. biroth, c. h., fischer, r. a., meisner, c. a. (eds.). evaluation and performance of permanent raised bed cropping systems in asia, australia and mexico,proceedings of a workshop, griffith, australia, 13 march 2005. aciar proceedings no. 121, pp.12-25. singh, y. 2003. crop residue management in rice-wheat system. 2003. in: addressing resource conservation issues in rice-wheat consortium for the indo-gangetic plains.cimmyt, new delhi, india, p.153. singh, y., s.s. bijay and j. timsina. 2005. crop residue management for nutrient cycling and improving soil productivity in rice-based cropping systems in the tropics. adv. agron. 85:269407. talukder, a.s.m.h.m., c.a. meisner, m.j. kabir, a.b.s. hossain and m. harun-ur-rashid. 2004. productivity of multi-crops sown on permanent raised beds in the tropics. in: new direction for a diverse planet: handbook and abstracts for the 4thinternational crop science congress, brisbane, australia, 26 september, 01 october 2004, p.173. talukder, a.s.m.h.m., m.a. sufian and c.a. meisner. 2006. rice, wheat and mungbean yields in response to n levels and management under a bed planting system. in: proceedings published in the 17thworld congress of soil science, bangkok, thailand, v. 1, symposium no. 11, p.351. timsina, j. and d.j.connor. 2001. productivity and management of rice-wheat cropping systems: issues and challenges. field crops res. 69: 93-132. abstract introduction materials and methods result and discussion bangladesh agron. j. 2017, 20 (1): 67-75 effect of simulated flooding and nitrogen application on nitrogen uptake of rice j.a. adjetey1* and q.s. mulbah2 1department of crop science and production, botswana university of agriculture and natural resources, private bag 0027, gaborone, botswana 2discipline of crop science, university of kwazulu-natal, scottsville 3209, pietermaritzburg, south africa corresponding author: jaadjetey56@gmail.com keywords: flooding, grain yield, nitrogen use efficiency, rice abstract in lowland rice production systems, flooding patterns vary during the cropping period and this poses a serious challenge to productivity due to the effect of flooding on the availability and uptake of nitrogen. the aim of this study was to examine the influence of various flooding patterns on nitrogen use in rice grown under simulated wetland conditions. rice was grown in a greenhouse at 0, 110 and 220 kg n ha-1 under well watered control conditions, continuous flooding, early flooding at tillering, and late flooding post-tillering. the results showed that continuous and early flooding increased tiller production and grain yield compared to late flooding or non-flooded conditions. although the highest grain yields under the different flooding patterns were obtained with 220 kg n ha-1, the combination of 110 kg n ha-1 and early flooding also significantly increased tiller productivity, nitrogen recovery, and agronomic nitrogen use efficiency (nue). there is the need to regulate the supply of nitrogen and water resources if grain yield and nue has to be increased at minimal costs. also, compared to well-watered conditions, rice production under flooded conditions lead to increased productivity and n rate must match realistic target yields. best results are obtained when flooding occurs in the early rather than later parts of the season. introduction rice is a principal grain crop in many sub-saharan african countries where it is a major source of carbohydrates for thousands of households. it is produced mainly for subsistence by rural farm families with very little or no modern agricultural inputs, including fertilizers. the rice farming system in sub-saharan africa is dominated by shifting cultivation in upland fields where about 7890% of the crop is produced under rain-fed conditions (balasubramanian et al., 2007). as a result, yield is low and seldom exceeds 1.5tha-1. by 2006, rice consumption had exceeded production (nasrin et al., 2015) by at least 50%, primarily as a consequence of declining output since the latter part of the 1980s (warda, 2007). although rice is not an aquatic plant, its yield can be improved with above average moisture supply (sarwar and khanif, 2005; kikuta et al., 2017). currently, sub-saharan african farmers are shifting towards lowland rice culture characterized by periodic flooding, to achieve increased productivity with the improved water supply associated with the lowlands, and also, promote sedentary farming (dolo, 2009). due to the uncertain flooding patterns associated with these lowlands, there is a need to develop insights into the effect of flooding patterns on the production of the crop. of the major fertilizer resources, nitrogen is the most intensively used in rice cropping systems. insufficient plant nitrogen results in chlorosis, reduced photosynthesis and stunted growth, while excessive amounts encourage luxuriant growth, lodging, diseases, and delays maturity (takebe and yoneyama, 1989; peng et al., 2010). like nitrogen, elevated 68 adjetey et al. soil moisture regimes promote the growth and development of rice crops (juraimi et al., 2009; kikuta et al., 2017). in most countries, rice is grown in wet or lowlands where water conditions are not easily predictable, particularly in respect of flooding times. excessive moisture can negatively influence nitrogen use efficiency, and consequently, crop yield. this study therefore, examined the effects of different simulated flooding patterns and nitrogen application rates on the growth and yield of rice. materials and methods the study was conducted in a greenhouse with day / night temperatures of 30oc / 20oc at the life sciences campus of the university of kwazulu-natal in pietermaritzburg. the cultivar “golden mountain # 1” (gm-1) was used in this study. the experiment was a factorial combination of four simulated flooding regimes and three nitrogen rates, laid out in a completely randomized block design with four replications. the water regimes which were simulations of possible field moisture situations in wetland rice cropping were: well watered control (nf), continuous flooding (cf), early flooding (ef), and late flooding (lf). double layer of clear plastic bags of 15 microns thickness were used to line the inner portion of the 4.8 l pots containing the flooded treatments, to prevent leakage through the pot drainage holes. each pot was then filled with 10 kg air-dried soil (28% clay, 1.5% organic matter, 1.5% acid saturation) and well watered. two hills were sown per pot with three seeds per hill, spaced 17 cm apart at a depth of 1 cm. prior to sowing, seeds were soaked in tap water for 24 h, following which they were incubated at 30 oc for another 24 h in order to stimulate vigorous germination. the plants were thinned to one seedling per hill at two weeks after sowing. tensiometers (irrometer company, california) were used to monitor the soil water status in the root zones of the plants subjected to no flooding, to ensure they were always well watered and soil moisture tension in the root zone was kept below 15 k pa throughout the experimental period. the flooding regimes were achieved by maintaining standing water at 5 cm from the soil surface in the 4.8 l pots. commencing at 21 days after sowing (das), the early flooding regime lasted until 51 das (i.e. 30 days) when tillers had fully formed, while the continuous flooding regime lasted up to 7 days before harvest (i.e. 70 days). the late flooding commenced at 51 das (near booting) and lasted for 40 days i.e. until 7 days before harvest. urea (46% n) was applied at 0, 110, and 220 kg n ha-1, in three split doses of 50% at 20 das; 25% at mid tillering (45 das) and 25 % at booting (60 das). the amount of fertilizer was calculated on the basis soil analysis results. there was a basal application of 20 kg p ha-1 using single super phosphate and no other fertilizers were required. a portable plant efficiency analyzer (hansatech, uk) was used to measure the leaf chlorophyll fluorescence at 30 das and at heading (65 das). a circular spot on the upper surface of each leaf was dark adapted for 20 minutes using dark adaptation clips, and the maximum quantum yield of photochemistry (fv/fm) recorded. tiller production was monitored weekly from three weeks after sowing until heading. at heading, one plant per pot was randomly harvested for leaf area, above ground biomass, and nitrogen determination. leaf area per plant was measured with a portable leaf area meter (li-3000, li-cor biosciences) equipped with a li3050a belt conveyor. above ground dry matter was measured after oven-drying at 70 oc for 48 h to constant masses. plant tissue nitrogen concentration was determined by the dumas combustion method, using a tru spec cn – elemental analyzer (leco corporation). whole dried shoot material was ground to powder using a ball mill (spex industries 8000). sub samples of 0.125 g were weighed, sealed in tin capsules and loaded for analysis. 69 effect of simulated flooding and nitrogen application on nitrogen uptake of rice nitrogen uptake at heading was determined as the product of the above ground dry mass and tissue nitrogen concentration. nitrogen use efficiency (nue) was assessed as nitrogen recovery efficiency and agronomic efficiency as: recovery efficiency = uptake from n fertilized pot – uptake from non fertilized pot x 100 n applied agronomic efficiency = grain weight in n fertilized pot – grain weight in non fertilized pot x 100 n applied panicle number, spikelet fertility, and grain weight were measured at maturity. unfilled spikelets were separated from filled spikelets by water flotation. grain weight was determined at grain moisture content of 14 %. the data were subjected to analysis of variance (anova) using the windows statistical software package, genstat version 12. the means of treatments showing significant difference were subjected to least significance difference (lsd) test. relationship between factors was further assessed by pearson’s correlation and regression analysis using the statistical software spss 15.0 for windows. results and discussion tiller and panicle production a high number of tillers (p < 0.001) was produced under both continuous and early flooding compared to the well watered controls and late flooding treatments (figure 1a). 0 2 4 6 8 10 12 nf cf ef lf t il le r n u m b er p o t -1 water regime 0 5 10 15 20 0 110 220 t il le r n u m b er p o t -1 nitrogen level (kg ha-1) nf cf ef lf 0 2 4 6 8 10 12 14 23 30 37 44 51 58 65 t il le r n u m b er p o t -1 days after sowing (das) 0 kg n ha-1 110 kg n ha-1 0 2 4 6 8 10 12 23 30 37 44 51 58 65 t il le r n u m b er p o t -1 days after sowing (das) nf cf ef lf a. b. c. d. 70 adjetey et al. fig. 1. effect of flooding regimes and nitrogen rates on tiller production in rice grown in green house conditions. error bars show 95% ci of means. chlorophyll florescence the ratio of variable florescence to maximum florescence (fv/fm) neither changed with nitrogen rate, nor with water regime at both 30 das and at heading (65 das). mean values ranged from 0.77 to 0.79 at 65 das, and 0.79 to 0.80 at heading (figure 2d), indicating that the plants were relatively free from stress. fig. 2. effect of flooding regimes and nitrogen rates on panicle production and chlorophyll fluorescence in rice grown in greenhouse conditions. error bars show 95% ci of means leaf area, dry mass and nitrogen status there was a significant interaction (p < 0.001) between the nitrogen rates and water regimes in respect of leaf area and shoot dry mass (figures 3a and 3b). when no nitrogen was applied, these parameters were significantly higher for those grown under early flooding compared to the other water regimes. at 110 kg n ha-1, water regime did not affect leaf area development, however, leaf area increased with continuous and late flooding at 220 kg ha -1. at 220 kg n ha-1 plants had the highest nitrogen concentration compared to those grown without nitrogen fertilizer (figure 3c). plants grown under non-flooded conditions also had high (p < 0.01) concentration compared to those continuously flooded. plant tissue nitrogen concentration increased with increasing nitrogen input under all but the late flooding water regime, in which nitrogen concentration showed little increase beyond the 110 kg n ha-1 rate. plant nitrogen uptake was 4 5 times higher at 110 and 220 kg n ha-1 than for the control 0 2 4 6 8 0 110 220 p a n ic le n u m b er p la n t -1 nitrogen level (kg ha-1) 0 2 4 6 8 10 nf cf ef lf p a n ic le n u m b er p la n t -1 water regime 0 kg n ha-1 110 kg n ha-1 220 kg n ha-1 y = 0.841x + 0.464 r² = 0.922** 0 2 4 6 8 10 12 0 5 10 15 p a n ic le n u m b er maximum tiller number 0.55 0.6 0.65 0.7 0.75 0.8 0.85 nf cf ef lf c h lo ro p h y ll fl o re sc e n ce ( f v /f m ) water regime 30 das c. d. a. b. 71 effect of simulated flooding and nitrogen application on nitrogen uptake of rice treatment. however, uptake was only 1.3 times higher at 220 kg n ha-1 compared to 110 kg n ha-1 (figure 3d). at 110 kg n ha-1, there was no significant difference in nitrogen accumulation for all the water regimes. at 220 kg n ha-1, nitrogen uptake by plants in both the continuous and early flooding regimes was significantly higher than those of the other two moisture regimes. nitrogen use efficiency nitrogen recovery was higher at 110 than at 220 kg n ha-1 (figure 4a). also, recovery at both nitrogen levels was higher with continuous and early flooding compared to the non-flooded and late flooded regimes. nitrogen recovery was less than 42% in all treatments but poorest in the late flooding treatment. the agronomic nitrogen use efficiency i.e. the ability of plants to increase yield in response to fertilizer input was higher for 110 than 220 kg n ha-1 under all the moisture regimes (figure 4b). at both nitrogen levels, agronomic nitrogen use efficiency was highest for early flooding, followed by continuous flooding. fig. 3. effect of flooding regimes and nitrogen rates on leaf area, dry mass, nitrogen concentration and uptake in rice grown in greenhouse conditions. error bars show 95% ci of means. spikelet fertility and grain yield spikelet fertility reduced only slightly (p < 0.05) in plants grown under continuous flooding (figure 4c). nitrogen rate did not affect (p > 0.05) spikelet fertility (figure 4d) and overall, 0 200 400 600 800 1000 1200 1400 nf cf ef lf l ea f a re a ( cm 2 p la n t -1 ) water regime 0 kg n ha-1 110 kg n ha-1 220 kg n ha-1 0 5 10 15 20 25 0 110 220 a b o v e g ro u n d d ry m a tt er ( g p la n t -1 ) nitrogen level (kg ha-1) nf cf ef lf 0 1 2 3 4 5 0 110 220 n it ro g en c o n ce n tr a ti o n (% ) nitrogen level (kg ha-1) nf cf ef lf 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 110 220 n it r o g e n u p ta k e ( g p la n t -1 ) nitrogen level (kg ha-1) nf cf ef lf c. d. a. b. 72 adjetey et al. spikelet fertility was always higher than 80% irrespective of treatments. there was nearly a twofold increase in grain yield per plant when nitrogen rate increased from 0 to 110 kg ha-1; however, only a small increase was observed beyond this level (figure 5a). plants subjected to early flooding produced the highest grain yield (p < 0.01) compared to those in the nonflooded and late flooding regimes (figure 5b). without nitrogen, yield was lower as a result of continuous and early flooding. at 110 kg n ha-1, yield increased with flooding irrespective of when it occurred. however, at 220 kg ha-1 yield was limited by the non-flooded and late flooding treatments. fig. 4. effect of flooding regimes and nitrogen rates on nitrogen recovery, agronomic use efficiency, and spikelet fertility in rice grown in greenhouse conditions. error bars show 95% ci of means. relationship between tiller number, dry mass nitrogen uptake and grain yield there was a significant positive linear relationship (r2 = 0.82, p < 0.001) between tiller and panicle number on one hand and grain yield on the other (figure 5c). although panicle yield was strongly dependent on tillering (r = 0.96), only 77% of the variation in grain yield could be explained by the maximum number of tillers produced. assessment of grain yield as a combined function of tillers and panicles revealed a non-significant estimate of the tiller coefficient (t pr. > 0.05), suggesting that unlike tillers, panicles were the principal determinants of grain yield (figure 5c). grain yield was positively related (r =0.85) to shoot biomass at heading (figure 5d) as well as total accumulated nitrogen in the plant (r = 0.89) at that time (figure 6). grain yield increased by 0.813 g (t pr. < 0.001) for every gram of increase in above ground dry matter and by 24.9 g for every gram of nitrogen accumulated by the time of heading. 0 10 20 30 40 50 nf cf ef lf n it ro g en f er ti li ze r re co v er y r a te ( % ) water regime 110 kg n ha-1 220 kg n ha-1 0 5 10 15 nf cf ef lf a g ro n o m ic n u e ( g g -1 ) water regime 110 kg n ha-1 220 kg n ha-1 0 20 40 60 80 100 nf cf ef lf s p ik el et f er ti li ty ( % ) water regime 0 20 40 60 80 100 0 110 220 s p ik el et f er ti li ty ( % ) nitrogen level (kg ha-1) nf cf ef lf c. d. a. b. 73 effect of simulated flooding and nitrogen application on nitrogen uptake of rice fig. 5. relationship between nitrogen application rate, shoot dry mass and tillers/panicle with grain yield. data points show means for different nitrogen application rates. error bars show 95% ci of means. fig. 6. relationship between nitrogen uptake at heading and grain yield. data points represent counts for both water regimes and nitrogen dosage (n = 48). 0 5 10 15 20 0 110 220 g ra in y ie ld ( g p la n t -1 ) nitrogen level (kg ha-1) 0 5 10 15 20 25 0 110 220 g ra in y ie ld ( g p la n t -1 ) nitrogen level (kg ha-1) nf cf ef lf y = 2.030x + 2.121 r² = 0.774** y = 2.391x + 1.104 r² = 0.824** 0 5 10 15 20 25 30 0 10 20 g ra in y ie ld ( g p la n t -1 ) number of tillers / panicles tillers panicles linear (tillers) y = 0.813x + 3.870 r² = 0.722* 0 5 10 15 20 25 0 10 20 30 g ra in y ie ld ( g p la n t -1 ) shoot dry matter at heading (g plant-1) y = 24.84x + 4.958 r² = 0.799** 0 5 10 15 20 25 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 g ra in y ie ld ( g p la n t -1 ) nitrogen uptake at heading (g plant -1) c. d. a. b. 74 adjetey et al. the overall grain yield response to the nitrogen treatments strongly correlated with the number of tillers, panicles and nitrogen uptake. however, the diminishing response between 110 and 220 kg ha-1 suggests that beyond the requirements for a realistic target yield e.g. 6 t ha-1 at the 110 kg n ha-1 level in this study, the excessive biomass has little immediate benefit to grain yield. such diminishing returns have been reported ( tilman et al., 2002; li et al., 2015). nitrogen application rate affected spikelet fertility only to a little extent as plants grown without nitrogen fertilizer did not produce many empty spikelets but rather only a few grain-bearing tillers. prolific tillering, coupled with inadequate nitrogen can lead to a reduction in the percentage of fertile spikelets (mauad et al., 2003). the fact that both n recovery and agronomic n use efficiency were higher at 110 kg n ha-1 than at 220 kg n ha-1, raises questions about the fate of excessive nitrogen application. low efficiency of nitrogen use at higher nitrogen rates have been attributed to losses via pathways such as no2, no and n2 emissions, and nh3 volatilization or to immobilization by soil microorganisms (hirel et al., 2007). to ensure efficient agronomic use of nitrogen, peng et al. (2006) have recommended the reduction of nitrogen rate to around 120 kg ha-1 in high tillering rice plants, a value close to the most efficient one adopted in this study, and to the 7090 kg ha-1 reported by shultana et al. (2015). in the current study, both continuous and early flooding treatments increased the number of tillers and panicles, above ground biomass, leaf area and nitrogen uptake and grain yield suggesting that they are better in lowland production than late flooding or non-flooded conditions. in the current study, however, because plants subjected to continuous or early flooding produced the highest grain yield in response to nitrogen compared to the other two water regimes, we suggest that those patterns of flooding are better for yield improvement. late flooding was the least useful of the flooded treatments as it not only led to reduced n uptake and n use efficiency but also stimulated the production of late and unproductive tillers with the potential for interfering with harvesting of mature panicles produced earlier in the season. the poor nitrogen use efficiency obtained under the late flooding and non-flooded conditions indicates that most of the applied nitrogen was wasted in those treatments. conclusion based on the findings of the study it was concluded that both continuous and early flooding led to a significant increase in nitrogen recovery, nitrogen use efficiency and grain production. all the simulated flooding conditions produced better yields than the non-flooded conditions. this suggested that irrespective of the flooding pattern, better yields were associated with lowland conditions although late flooding was the least desirable of the options. thus flooding regimes are significant for improved yields, in lowland areas that are fed by abundant rainfall. references balasubramanian, v., m. sie, r.j. hijmans and k. otsuka. 2007. increasing rice production in sub-saharan africa: challenges and opportunities. adv. agron. 94: 55-133. dolo, j. s. 2009. nation-wide assessment of wetlands in large rubber concession areas. ministry of agriculture, monrovia, liberia. 75 effect of simulated flooding and nitrogen application on nitrogen uptake of rice hirel, b., j. le gouis, b. ney and a. gallais. 2007. the challenge of improving nitrogen use efficiency in crop plants: towards a more central role for genetic variability and quantitative genetics within integrated approaches. j. exp. bot. 58: 2369-2387. juraimi, a. s., m. a. h. saiful, m. begum, a. r. anuar and m. azmi. 2009. influence of flooding intensity and duration on rice growth and yield. pertanika j. trop. agric. sci. 32: 195-208. kikuta, m., d. makihara, n. arita, a. miyazaki and y. yamamoto. 2017. growth and yield responses of upland nericas to variable water managementunder field conditions. plant prod. sci. 20(1): 36-46. li, y., y. chen, c. wu, x. tang and x. ji. 2015. determination of optimum nitrogen application rate in zhejiang province, china, based on rice yields and ecological security. j. integ. agric. 14(12): 2426-2433. mauad, m., c. a. c. crusciol, f. h. grassi and j. c. correa. 2003. nitrogen and silicon fertilization of upland rice. scientia agrico. 60: 761-765. nasrin, s., j. b. lodin, m. jirstrom, b. holmquist, a. a. djurfeldt and g. djurfeldt. 2015. drivers of rice production: evidencefrom five sub-saharan countries. agr. food sec. 4(12): 1-19. peng, s., r. j. buresh, j. huang, x. zhong, y. zou, j. yang, g. wang, y. lui, r. hu, q. tang, k. cui, f. zhang and a. dobermann. 2010. improving nitrogen fertilization in rice by site-specific n management. a review. agron. sustain. dev. 30: 649-656. shultana, r., m. a. a. mamun, m. a. k. bhuiyan and a. j. mridha. 2015. response of nerica rice to nitrogen fertilization. bangladesh agron. j. 18 (2): 9-14. sarwar, m. j. and y. m. khanif. 2005. effect of different water levels on rice yield and cu and zn concentration. j. agron. 4: 116-121. takebe, m. and t. yoneyama. 1989. measurement of leaf color scores and its implication to nitrogen nutrition of rice plants. japan agric. res. quart. 23: 86 93. tilman, d., k. g. cassman, p. a. matson, r. naylor and s. polasky. 2002. agricultural sustainability and intensive production practices. nature. 418: 671-677. warda. 2007. africa rice trends 2007 brief. africa rice center (warda), cotonou, benin. bangladesh agron. j. 2019, 22 (1): 121-130 seed harvesting at different maturity stages of siliqua on seed quality of rapeseed-mustard varieties a.h.m.m.r. talukder1*, m. biswas2, m.n.h. miah3, m.a. kashem4 and l. nahar5 1scientific officer, plant physiology division, bari, joydebpur, gazipur, 2professor, jashore university of science & technology, jashore­7408, 3professor, dept. of agronomy and haor agriculture, sylhet agricultural university, sylhet­3100, 4professor, dept. of soil science, sylhet agricultural university, sylhet­3100, 5asstt. professor, dept. of agricultural botany, sher-e-bangla agricultural university, dhaka-1207. *corresponding e-mail: motiurbari@yahoo.com (received: 25 september 2019, accepted: 28 november 2019) keywords: moisture percentage, germination percentage, vigor index, rapeseed-mustard, speed of germination, seedling length abstract a laboratory experiment with three replicates was conducted at plant physiology division research laboratory of bangladesh agricultural research institute (bari) during november, 2015 to observe the seed quality of rapeseed-mustard by harvesting at different maturity stages of siliqua. seeds were collected from siliqua of different rapeseed-mustard varieties and harvesting was made at different maturity stages based on their external color i.e., green, pale yellow, golden yellow and full maturity stage of siliqua. after harvesting of siliqua as per external color seeds were dried naturally about 48 hours and were packed in polythene and stored at laboratory environment for next season uses. under laboratory condition seeds were evaluated in terms of moisture and germination percentage, speed of germination, root and shoot length, vigor index etc. moisture content was found significantly at elevated level in respect of mustard varieties of bari sarisha-14 (v2), bari sarisha-6 (v3) and tori-7 (v4). the variety tori-7 and bari sarisha-14 showed the highest vigor index-ii & vigor index-i, respectively. among the harvesting stages, most of the parameters showed the highest standards in seeds harvesting at full maturity of siliqua stage (h4) followed by the golden yellow siliqua stage (h3) and pale yellow siliqua stages seeds (h2).irrespective of rapeseed-mustard varieties seed collected from golden yellow and pale yellow siliqua stages could be stored up to twelve month for next season without significant loss in terms of germination percentage and vigor followed by full maturity stages of siliqua harvested seeds (h4). introduction harvest stage is one of the most important factors that influence the seed quality (emilly et al., 2016). harvest stage also affects the performance of seeds during storage and field condition. for this reason seed production technology advises the seeds should be harvested as close as possible to physiological maturity. harvesting of crop at right stage of maturity assume greater importance because stage of maturity greatly influence the seed yield and quality. cost effective yield and quality of seed manipulates along with stage of maturity at harvest (demir & balkaya, 2008). earlier and later harvested seeds than physiological maturity seeds remain respectively immature and more likely to be deteriorating as they are about:blank 122 talukder et al. subjected to adverse conditions, which reduces the seed quality (marcosfilho, 2005). seed quality like viability and vigor are the features of seed that facilitate the emergence and establishment of normal seedlings under wide range environments (khan et al., 2012). seedling emergence and crop establishment are the seed germination and vigor which has an important influence on the establishment of plant population that affects crop yield (hampton, 2002). seed quality likes genetically and physically pure seed, vigor and viable seeds and seeds free from seed borne pathogen produce normal seedlings which are typically determined by means of laboratory tests (perry, 1980). these seed quality may deteriorates during field weathering (higher temperature, relative air humidity and oxygen/carbon dioxide ratio during pre-harvest), lacking of identify the optimum harvesting time (early and/or later harvesting) and storage. laboratory germination test is important issue to know the pre information about performance of seeds under field condition due to significant correlation coefficients between field emergence and standard laboratory germination tests. laboratory testing of seed germination is to assess seed quality or viability and to predict performance of the seed and seedling in the field. laboratory seed testing aid to obtained information about different quality attributes viz., purity, moisture percentage, germination, vigor and health. early harvesting stage prior to full maturity resulted poor quality on the account of seed immaturity. so, this research was carried out to investigate the seeds quality of rapeseed-mustard cultivars at different stages of development and maturity. materials and methods the laboratory experiment was conducted at plant physiology division laboratory under bangladesh agricultural research institute (bari), joydebpur, and gazipur1701 (located in between 23°53' and 24°21' north latitudes and in between 90°09' and 92°39' east longitudes) during the period from 01 november to 07 november, 2015. previously harvested of rapeseed-mustard seeds from four different maturity stages of siliqua were collected and these seeds were used as. h1 = green siliqua stage harvested seed (h1 = bari sarisha-11, bari sarisha14, bari sarisha-6 and tori-7 were harvested at 88, 66, 81 and 65 days after sowing), h2 = pale yellow siliqua stage harvested seed (h2 = bari sarisha-11, bari sarisha-14, bari sarisha-6 and tori-7 were harvested at 98, 75, 90 and 74 days after sowing), h3 = golden yellow siliqua stage harvested seed (h3 = bari sarisha-11, bari sarisha-14, bari sarisha-6 and tori-7 were harvested at 104, 85, 100 and 85 days after sowing) and h4 = full maturity siliqua stage harvested seed (h4 = bari sarisha-11, bari sarisha-14, bari sarisha-6 and tori-7 were harvested at 109, 89, 103 and 89 days after sowing). the experiment was conducted in completely randomized design (factorial) with three replications. the laboratory experiment was conducted just before observe the field performances of different harvesting stages seeds. before initiate the laboratory experiment, collected seeds according to the treatment were preserved under freezing condition at 0 °f (-18 °c) or lower temperature. twenty five seeds were picked up randomly from the each well-mixed seed lot. enough care was taken for seed selection so that there is no causing biasness of results. total forty eight petri dishes were kept in a well-ventilated room at room temperature (°c) for certain period (07 days). then, filter paper was placed in the petridis and moistened by drops of water from a wash bottle before seed placement. twenty five seeds according to treatments were placed in the petri dishes and everyday counted the germinated seeds on the basis root and shoot appearance. seed harvesting of mustard 123 moisture percentage according to ista (1976) the moisture content of seed sample was determined. a blank moisture cup along with its cover was weighed and then twenty gram of each seed sample of rapeseed-mustard variety was taken into moisture cup and put into a pre-heated oven at temperature of 130.2o°c for one hour (morshedet al.,2003). then the weight of the container with its cover and contents were taken. the seed samples were cooled and weighed to work out the percent moisture content of the grains by using following formula (khatunet al., 2009). where, m1 is the weight in (g) of the container and its cover, m2 is the weight in (g) of the container and its cover along with contents (seed) before drying and m3 is the weight in (g) of the container and its cover along with contents (seed) after drying. germination percentage according to ista (1976) germination percentages were carried out. twenty five seeds were collected from each seed lot according to treatment and put them on blotting paper into the petri dishes at room temperature. after a week normal (well developed primary root system, intact hypocotyls without damage, an intact plumule a well-developed green leaf), abnormal (damaged, deformed and diseased seedlings) were counted. germination percentage was counted by using following formula germination (%) = root, shoot length (cm) and dry weight of seedling-1 (g) after a week 10 seedlings were randomly selected for study on the characters. the seedlings were divided into root and shoot and their lengths were measured in centimeter. the sum of root and shoot length was considered as seedling length. after measuring the root and shoot length stated above, root and shoot were put into paper packet separately, and placed them into pre-heated oven at 70o °c for 48 hours (agrawal, 1986) to obtain seedlings-1 dry weight and expressed in gram (g). speed of germination speed of germination was calculated by using following formula (sharma et al., 2013) where, n is the number of germinated seeds at each day; d is the number of days after the start of the experiment, n is the total number of seeds. seedling vigor index seedling vigor index was calculated according to reddy and khan (2001) by using following formula vigor index­ i = percent of germination × total dry weight of seedling vigor index­ ii = percent of germination × length of seedling 122 talukder et al. the collected data on each treatment was statistically analyzed to obtain the level of significance using the computer based software mstat­ c developed by russel (1986). mean differences among the treatments were tested with least significant difference (lsd) test at 5% level of significance. results and discussion effects of varieties seed moisture content was observed among the rapeseed-mustard varieties significant (table 1). higher moisture content (6.67%) was observed in var. bari sarisha-6 (v3) that was statistically similar with the var. bari sarisha-14 (v2) and tori-7 (v4) (6.63 and 6.30 %, respectively). it might be due to the bolder seed size. the lowest moisture content (5.61%) was observed in var. bari sarisha-11 (v1). the tested rapeseed-mustard varieties did not differ significantly in terms of germination percentage (table 1). . the variety tori-7 produced significantly the longest root (5.44 cm) than other varieties while bari sarisha-14 produced the shortest root (3.52 cm). shoot length (cm) differed significantly among the different varieties where bari sarisha-11 produced the maximum shoot (3.61 cm) that was statistically similar to bari sarisha-14 and tori-7. the variety bari sarisha-6 produced the shortest shoot length. significant variations were observed in terms of seedling length among the rapeseed-mustard varieties and the longest seedling (8.91 cm) was noted in variety tori-7 .this variety also contributed longer root and shoot length (table 1). similarly, mahesha et al. (2001b) also reported that varieties differed significantly in respect of seedling length harvested at different maturity dates. significant differences in terms dry weight of seedling-1 among oilseed rape cultivars can be attributed to variation in genetic constitution, which may strongly influence seed vigor (ghassemi – golezani et al., 2010). significantly among the different varieties the variety bari sarisha-14 (v2) produced the highest dry weight of seedling-1 while other three varieties produced significantly lower and statistically similar. variety had no significant effect for speed of germination and ranged from 25.6 to 25.7%. the maximum vigor index-i (2.08) was produced by bari sarisha-14 which was statistically superior to other varieties. this might be due to the higher germination percentage and dry weight of seedling-1. the variety tori-7 (v4) produced significantly the highest vigor index-ii (854.2) while bari sarisha-14 had the lowest vigor index-ii and it was statistically at par with bari sarisha-6 (table 1). table 1. seed quality parameters of rapeseed-mustard varieties irrespective of seeds harvested at different stages of siliqua maturity varieties moisture (%) germin -ation (%) root length (cm) shoot length (cm) seedling length (cm) dry weight seedling-1 (g) germinati on speed (%) vigor index-i vigor index-ii v1 5.61 b 96.0 4.65 b 3.61 a 8.30 b 0.019 b 25.7 1.83 b 791.6 b v2 6.63 a 95.0 3.52 d 3.51 a 7.03 c 0.022 a 25.6 2.08 a 669.1 c v3 6.67 a 96.0 4.10 c 3.24 b 7.30 c 0.017 b 25.7 1.67 b 702.8 c v4 6.30 a 95.0 5.44 a 3.46 a 8.91 a 0.017 b 25.7 1.67 b 854.2 a lsd0.05 0.63 ns 0.28 0.17 0.32 0.0022 ns 0.18 40.2 cv (%) 12.1 4.42 7.53 6.10 4.86 14.2 4.20 12.3 6.41 seed harvesting of mustard 123 note: v1 = bari sarisha­ 11; v2 = bari sarisha­ 14; v3 = bari sarisha­ 6; v4 = tori­ 7 effects of seeds at different harvesting stages of siliqua maturity seeds of different harvesting stages of siliqua maturity showed significant effect on moisture percentage. the moisture contents of the seed decreased with delay in the date of harvesting. seeds collected from green siliqua harvesting stage (h1) showed significantly the highest moisture percentage (7.20%) and the lowest moisture percentage (5.82%) was observed with the seeds that were collected from full maturity siliquae (h4) stage which was at par with pale yellow (h2) and golden yellow siliquae (h3) stages (table 2). declining in moisture content and increasing seed mass resulted from delayed harvesting beyond physiological maturity. germination percentage varied from 87 to 99% among different harvesting stages seeds. the highest germination percentages were 96 and 99% where seed contained 6.22, 5.99 and 5.82% moisture at pale yellow golden yellow and full maturity siliqua harvesting stages, respectively. in case of early harvesting stage (h1) the germination was decreased to 87% and seed contained highest moisture (7.20%). lower germination (%) in early harvested seeds may also be due to presence of more number of immature and unfilled seeds. but, hay and white house (2017) stated that high quality seeds can recommend if the germination percentage observed at 85% at various maturity stages. the root length was gradually increased onwards the maturity stages of seeds. the highest root length (4.87 cm) was recorded from the seeds harvested at full maturity siliqua stage. seeds harvested at pale yellow and golden yellow siliquae stages produced significantly different and average root length was 4.55 cm and 4.51 cm, respectively. the lowest root length (3.74 cm) was found in green siliqua harvesting stage. similarly, el-abady (2015) also stated that the lowest root length was obtained from small seed. shoot length did not differ significantly due to seeds harvested at different maturity stages of siliqua. it ranged from 3.42 cm to 3.53 cm. the full maturity suliqua (h4) stage produced the maximum seedling (8.30 cm) that was statistically similar with that of golden yellow siliqua (h3) stage of maturity. the green siliqua (h1) stage of maturity produced the shortest seedling length (7.20 cm). the highest seedling length was recorded in later harvesting stage, which might have been resulted from higher germination percentage and vigorous growth. mahesha et al. (2001b) stated that seedling length was the highest in seeds collected at 35 days after flowering and the lowest in 30 days after flowering in sunflower. the seeds of full maturity of siliqua harvesting stage were the best in terms of seedling dry weight (0.022 g seedling-1) that was statistically similar with seeds of golden yellow siliqua harvesting stage). early harvesting stage gave the lowest dry weight seedling-1 (0.015 g). khatun et al. (2010) stated that due to restricted supply of nutrient from mother plant, disruption of vascular connection, utilization of various physiological and metabolic process dry weights decreased. the seeds of pale yellow (h2), golden yellow (h3) and full maturity siliqua (h4) stages had statistically higher speed of germination (table 2). shete et al. (1992) reported increase in germination with advancement of harvesting date. seeds of green siliqua (h1) stage had the lowest germination speed (23.5). according to abdul-baki and anderson (1973) stated that seed lot showing a higher vigor index is considered to be more vigorous. higher vigor index-i (2.20) was found with full maturity of siliqua (h4) harvesting stage, which was similar to h3. the lowest vigor index-i (1.30) was observed in green siliqua harvesting (h1) stage. harvesting the seed before the attainment of physiological maturity recorded lesser viability and vigor potentials due to more number of immature seeds with high moisture content as reported in pea by matthew (1973). harvesting stage of h4 markedly increased 122 talukder et al. vigor index-ii. seeds harvested at the stage of full maturity of siliqua (h4) showed appreciably higher seed vigor index-il probably due to associative effect of germination percentage and seedling length. increased seed vigor index-ii might be due to the maturation of seeds of later harvesting stages resulting improved germination percentage and seedling length (gore et al., 1997). interaction effects of varieties and seeds of different harvesting stages of siliquae maturity the interaction between varieties and seeds from different harvesting stages did not produce significant effect on moisture content of seed (table 3). moisture content ranged from 5.30 to 8.57%. the germination percentage did not differ significantly due to interaction effects of varieties and harvesting stages seeds (table 3). the interaction of harvesting stages seeds and the varieties showed a significant effect on root length (table 3). in variety tori-7 (v4), with seeds of full maturity siliqua harvesting stage (h4) resulted the highest root length (6.48 cm). interaction effects of the variety bari sarisha-14 (v2) with seeds of golden yellow siliqua stage (h3) (v2h3) was recorded the lowest root length (3.34 cm). table 2. effects of seeds harvested at different stages of siliqua maturity on seed quality parameters of rapeseed-mustard irrespective of varieties harvesting stages moisture (%) germination (%) root length (cm) shoot length (cm) seedling length (cm) dry weight seedling-1 (g) germination speed (%) vigor index-i vigor index-ii h1 7.20 a 87.0 b 3.74 c 3.45 7.20 c 0.015 c 23.5 b 1.30 c 628.3 c h2 6.22 b 96.0 a 4.55 b 3.42 7.97 b 0.017 b 25.9 a 1.70 b 767.7 b h3 5.99 b 99.0 a 4.51 b 3.53 8.04 ab 0.021 a 26.6 a 2.11 a 798.3 ab h4 5.82 b 99.0 a 4.87 a 3.43 8.30 a 0.022 a 26.6 a 2.20 a 823.4 a lsd(0.05) 0.63 3.59 0.28 ­ 0.32 0.0044 0.88 0.18 40.2 cv (%) 12.1 4.52 7.53 6.07 4.86 14.2 4.16 12.3 6.41 note: h1 = green siliqua stage harvested seed; h2 = pale yellow siliqua stage harvested seed; h3 = golden yellow siliqua stage harvested seeds; h4 = full maturity siliqua stage harvested seeds interaction effects did not differ significantly in respect of shoot length. the effect of seeds harvested at different stages of siliqua maturity on seedling length of four rapeseed-mustard varieties was markedly influenced (table 3). the maximum seedling length was observed by the interactions of v4 h4, v4h3 and v4h2 while the minimum in v2 h1. vigor index­ i did not differ significantly but all varieties responded significantly to harvesting stages of seeds, producing higher seed vigor index­ ii. the maximum seed vigor index­ ii (963.9) was recorded in the interaction of v4h4 that was statistically similar with interaction of v4h3 and v4h2. the lowest seed vigor index­ ii (551.6) was noted in the interaction of v2h1 (table 3). seed harvesting of mustard 123 table 3. interaction effects of varieties and seeds harvested at different stages of siliqua maturity on seed quality parameters of rapeseed-mustard under laboratory condition interaction (vh) moisture (%) germination (%) root length (cm) shoot length (cm) seedling length (cm) dry weight seedling-1 (g) germination speed (%) vigor index-i vigor index-ii v1h1 5.83 89.0 3.99 d-f 3.61 7.60 c 0.015 23.7 1.31 678.4 e-g v1h2 5.30 95.0 4.91 c 3.58 8.50 b 0.018 25.4 1.65 804.3 cd v1h3 5.57 100.0 4.76 c 3.68 8.44 b 0.023 26.8 2.33 844.0 bc v1h4 5.73 99.0 4.95 c 3.56 8.51 b 0.021 26.5 2.04 839.7 bc v2h1 8.57 83.0 3.45 fg 3.24 6.70 e 0.017 22.1 1.40 551.6 h v2h2 6.30 97.0 3.36 g 3.55 6.91 de 0.021 26.2 2.00 672.8 e-g v2h3 5.87 100.0 3.34 g 3.68 7.01 ce 0.024 27.0 2.43 701.3 e-g v2h4 5.80 100.0 3.93 d-f 3.57 7.51 cd 0.025 26.9 2.50 750.6 de v3h1 7.10 91.0 3.93 d-f 3.28 7.21 ce 0.014 24.3 1.24 653.5 fg v3h2 7.10 96.0 3.99 d-f 3.19 7.20 ce 0.014 25.8 1.40 690.5 e-g v3h3 6.63 99.0 4.18 d 3.20 7.40 cd 0.019 26.3 1.84 728.0 d-f v3h4 5.83 100.0 4.10 de 3.30 7.40 cd 0.022 26.5 2.20 739.3 de v4h1 7.23 87.0 3.59 eg 3.67 7.30 ce 0.014 23.6 1.21 629.8 gh v4h2 6.17 97.0 5.93 ab 3.34 9.30 a 0.016 26.1 1.60 903.1 ab v4h3 5.90 99.0 5.77 b 3.55 9.32 a 0.018 26.5 1.81 919.8 ab v4h4 5.90 99.0 6.48 a 3.29 9.80 a 0.021 26.5 2.07 963.9 a lsd (0.05) 1.26 7.18 0.055 0.35 0.64 0.002 1.78 0.37 80.4 cv (%) 12.1 4.52 7.53 6.07 4.86 14.2 4.16 12.3 6.41 note: v1 = bari sarisha-11; v2 = bari sarisha-14; v3 = bari sarisha-6; v4 = tori-7; h1 = green siliqua stage harvested seed; h2 = pale yellow siliqua stage harvested seed; h3 = golden yellow siliqua stage harvested seed; h4 = full maturity siliqua stage harvested seed pearson’s correlation matrix among different seed quality parameters of seeds harvested at different maturity stages of siliqua correlation matrix among the seed characters of rapeseed-mustard has been shown in table 4. a positive and significant correlation was observed among root length, germination, germination speed, seedling length and vigor index­ ii; among germination, germination speed, dry matter weight, seedling length, vigor index­ i, vigor index­ ii; among germination speed, dry matter weight of seedling, seedling length, vigor index­ i and vigor index­ ii and among dry matter weight, vigor index­ i and vigor index­ ii and between seedling length and vigor index­ ii and between vigor index-i and vigor index­ ii. negative and non-significant correlation was found between root length and shoot length; among shoot length, germination, germination speed; between dry matter weight and moisture. a positive correlation (r = 0.596) between germination and dry matter was found by mehta et al. (1993). reddy and khan (2001) found a positive and significant correlation (0.68**) between germination and seedling dry weight, vigor index­ i (0.91**) and vigor index­ ii (0.97**). table 4. pearson’s correlation matrix among different seed quality parameters of rapeseed-mustard correlation co-efficient (r-value) character root length (cm) shoot length (cm) germination (%) germination speed dry weight seedling1 (g) moisture content seedling length vigor index-i vigor index-ii root length 1.00 0.09ns 0.32* 0.32* 0.045* -0.35* 0.97** 0.083n s 0.91** shoot length 1.00 -0.04ns -.009ns 0.17ns -0.34* 0.16ns 0.12ns 0.10ns germinatio n (%) 1.00 0.98** 0.57** -0.34* 0.31* 0.63** 0.64** germinatio n speed 1.00 0.56** -0.37** 0.31* 0.62** 0.64** dry weight seedling-1g 1.00 -0.26ns 0.09ns 0.97** 0.29* moisture content 1.00 -0.44** -0.28* -0.47** seedling length 1.00 0.11ns 0.93** vigor index-i 1.00 0.34* vigor index-ii 1.00 conclusion irrespective of rapeseed-mustard varieties seed collected from golden yellow stage of siliqua could be stored up to twelve month for next season without significant loss in terms of germination percentage and vigor followed by full maturity stages of siliqua harvested seeds (h4). the results of this study could create the awareness among the rapeseed-mustard growers’ to harvest the crop earlier such as pale yellow or golden yellow color stage of siliqua before attainment of full maturity considering the time saving. acknowledgements seed harvesting of mustard 129 we acknowledge the “research and research infrastructure development and extension project” funded by government of the people’s republic of bangladesh, implemented by bangladesh agricultural research institute (bari), gazipur-1701, for providing fund to conduct the study. we also acknowledge the authority of the plant physiology division of bari to conduct the research work providing adequate laboratory facilities. references abdul-baki, a.a., and j.d. anderson. 1973. physiological and biochemical deterioration of seed. in: kozlowski, t.t. (2nd eds.). seed biology. academic press, new york, london, pp.283-315. agrawal, p.k. 1986. seed vigor concepts and measurements. in:srivastava, j.p. and l.t. simarsk (eds.) proceeding of the seed production technology. icarda, aleppo, syria, pp.190-198. aosa. 2009. seed vigor testing handbook. contribution no. 32 to the handbook on seed testing. demir, i. and a. balkaya. 2005. seed development stages of kale (brassica oleracea var. acephala l.) genotypes in turkey hort. sci. 32: 147-153. demir, i., a.m. ashirov and k. mavi. 2008. effect of seed production environment and time of harvest on tomato (lycopersicon esculentum) seedling growth. res. j. seed sci. 1: 1-10. el-abady, m.i. 2015. influence of maize seed size/shape, planted at different depths and temperature on seed emergence and seedling vigor. res. j. seed sci. 8(1): 1-11. emilly, r.a., m.s. de, s.d. andréia, v.s. tiago, g.r. cleiton and t.r.a. hugo. 2016. different harvest times and physiological quality of coriander seeds. rev. bras. eng. agr. amb. 20: 133-137. ghassemi-golezani, k.s. khomari, b. dalil, a. hosseinzadehmahootchy and a. chadordooz-jeddi. 2010. effects of seed aging on field performance of winter oilseed rape. j. food agric environ. 8: 175-178. gore, s.v., r.b. patil and g.r. wankhade. 1997. effect of maturity period and harvesting time on seed quality in soybean (glycine max. [l.] merill) cultivars. seed res. 25: 45-49. hampton, j.g. 2002. what is seed quality? seed sci.tech. 30: 1-10. hay, f.r. and k.j. whitehouse. 2017. rethinking the approach to viability monitoring in seed gene banks. conserv. physiol. 5(1): 1-13. ista. 1976. international rules for seed testing. seed sci. tech. 4: 3-49. khan, n., r.h. kazmi, l.a. willems, a.w. van heusden, w. ligterink and h.w hilhorst. 2012. exploring the natural variation for seedling traits and their link with seed dimensions in tomato. plos one,7(8): e43991. khatun, a., g. kabir and m.a.h. bhuiyan. 2009. effect of harvesting stages on the seed quality of lentil (lens culinaris l.) during storage. bangladesh j. agric. res. 34: 565-576. 130 khanum et al. khatun, a., m.a.h. bhuiyan, a. nessa and s.b.m. hossain. 2010. effect of harvesting time on yield and yield attributed of chickpea (cicer arietinum l). bangladesh j. agric. res. 35: 143-148. mahesha, c.r., a.s.i. channaveeraswam, m.b. kurdikeri, m. shekhargouda and m.n. merwade. 2001. storability of sunflower seeds harvested at different maturity dates. seed res. 29(1): 98-102. marcos-filho, j. 1999. strength tests: importance and use. in: krzyzanowski, f.c. r.d. vieira and j.b. france neto (eds.) seed vigor: concepts and tests. londrina: abrates, pp.1-21. matthew, s. 1973. the effect of time of harvest on the viability and preemergence mortality in soil of pea (pisum sativum l.) seeds. ann. appl. bio.73: 211-219. mehta, c.j., m.s. kuhad, i.s. sheoran and a.s. nandwal. 1993. studies on seed development and germination in chickpea cultivars. seed res. 21: 89-91. morshed, m.s., m. begum, m.a. bashar and w. sultana. 2003. effect of storage containers on seed quality of three pulses. bangladesh j. life earth sci. 15: 107-112. nonogaki, h., g.w. bassel and j.d. bewley. 2010. germination-still a mystery. plant sci. 179: 574–581. perry, d.a. 1980. the concept of seed vigor and its relevance to seed production techniques. in: hebblethwaite, p.d (ed) seed production. proc. 28th easter school in agric. sci., univ. nottingham. butterworths: london reddy, y.t.n. and m.m. khan. 2001. effect of osmopriming on germination, seedling growth and vigor of khirni (mimusops hexandra) seeds. seed res. 29: 24-27. russell, d.f. 1986. mstat-c package programme.crop and soil science department, michigan university, usa. sharma, p.v., sardana and s.s. kandhola. 2013. effect of sowing dates and harvesting dates on germination and seedling vigor of groundnut (arachis hypogaea) cultivars. res. j. seed sci. 6: 1-15. shete, d.m., a.r. singh, a.p. suryawanshi and v.s. hudge. 1992. seed germination and vigor at harvest in sunflower. ann. plant phys. 6: 125132. microsoft word 12. baj-301_revised 105 bangladesh agron. j. 2018, 21(1): 105-115 productivity and nutrient balance of lentil mungbean -t. aus t. aman rice cropping pattern in high barind tract m. s. hossain1*, s. m. m. alam1, m. y. abida1, m. k. hasan2 and a. s. m. m. r. khan2 1on-farm research division, bari, barind, rajshahi 2on-farm research division, bari, gazipur, bangladesh *corresponding author, e-mail:shossain72@yahoo.com (received: 1 january 2018, accepted: 11 april 2018) keywords: four crops pattern, system productivity, mbcr and nutrient balance abstract a field experiment viz. was conducted at farmers’ field of field service research division site, kadamshahar, godagari, rajshahi under high barind tracts to evaluate the the effect of the intensive cropping on system productivity and economic returns as well as nutrient balance and changes in soil fertility of four crop-based cropping pattern lentil –mungbean -t.aus -t.aman during 2015-2016 and 2016-2017. the lentil mungbean-t.aus -t. aman rice cropping pattern was considered as improved pattern (ip) and compared with the farmers’ practice (fp) of boro fallow -t.aman rice cropping pattern. the lentil-mungbeant.aus -t.aman cropping pattern was involved with higher cultivation cost but having the higher rice equivalent yield (rey 15.01 t ha-1), gross return (tk. 265500 ha-1), gross margin (tk. 134750 ha-1) and marginal benefit-cost ratio (1.38). this cropping pattern gave 46% higher rey compared to the existing boro-fallow-t. aman rice pattern. the four crop pattern took 345 days in a year for its cycle completion. incorporation of legume residues into the soil in ip increased soil organic matter, total n, available p and zn contents, as observed after two crop cycles. the ip increased n, p and k uptake by the crops in the sequence. the apparent balance, i.e. difference between inputs and outputs for n and k was negative. the apparent p balance was positive in ip while it was negative in fp. therefore, it is concluded that the practicing lentilmungbean-t.aus-t.aman rice cropping pattern is a productive and profitable system of production technology in the high barind tract. introduction bangladesh is the densely populated (1237 per sq. km.) country of the world with an increasing population rate of 1.05% per year (world meters, 2017). at present total cultivable land is 7.95 million hectare (bbs, 2016) which is decreasing at the rate of about 0.44% per year. there is a very little scope for increasing cultivable land but there are some rooms for increasing cropping intensity from the present 194 to 400% by incorporating short duration crops like lentil, mungbean and aus rice in the rice based cropping pattern. sustainable crop production in bangladesh through improvement of cropping pattern in rice based cropping system is regarded as increasingly important in national issues such as food security, poverty alleviation and creation of job opportunity. the main challenge of the new millennium is to increase per unit yield by at least 50% through manipulating the limited land resource. in case of production agronomy, targeting high yield with high cropping intensity and productivity is the most logical way to raise the total production. in order to produce more food within a limited area, most important options are to increase the cropping intensity producing three or more crops over the 106 hossain et al. same piece of land in a year and ii) to increase the production efficiency of the individual crop by using optimum management practices. soil nutrients (n, p, k, s, zn, b etc.) play an important role for regulating the supply of nutrients to plant (konrad et al., 2001). high yielding varieties of crops uptake higher amount of nutrients from soils resulting in depletion of soil organic matter and deterioration of soil fertility that poses a great threat to sustainable crop production. moreover, continuous cropping without adequate replacement of removed nutrients and nutrient loss through erosion, leaching, and gaseous emission is causing a depletion soil fertility as well as soil organic matter (yu, et al., 2014 and tirol-padre et al., 2007). the areas of pulse in rabi season are decreased because of increasing cultivation of irrigated boro rice. recently with the development of short duration rice and pulse crops an opportunity has been created to accommodate four crops in the same piece of land in a year. high barind tract is recognized as drought prone area in bangladesh and its soil fertility is low compared to other parts of the country. so, lentil and mungbean were chosen as component crop in four crop based cropping pattern by replacing boro rice. besides, lentil and mungbean are the low water consuming crops. t. aus rice can be cultivated with minimum irrigation water as monsoon remains active during its growing period. the present study was thus undertaken to evaluate the economic feasibility of growing four crops in respect of productivity and nutrient balance in a year in the same piece of land by incorporating lentil, mungbean and t. aus rice in the present cropping pattern boro-fallow-t. aman rice. materials and methods the four crop based cropping pattern (lentil-mungbean-t.aus-t.aman) was tested in the farmer's field of fsrd site, kadamshahar, godagari, rajshahi during 2015-16 and 2016-17. the soil of the experimental plots belongs to amnura series under aez 26. the soil of the experimental site was collected from two soil depth (0-15 cm and 15-30 cm) and analyzed and chemical properties of initial and final soil (after two crop cycle) were presented in table 1 and table 2. the experiment covered one hectare of land. land was selected based on the discussion with local farmers, dae personnel and available secondary information. the improved pattern (ip) lentil-mungbean-t.aus-t.aman (ip) was compared with farmers’ practice (fp) borofallow-t.aman. the experiment was designed with two cropping patterns as a treatment and laid out in a randomized complete block design with six dispersed replications. in ip, lentil var. bari masur-6, mungbean var. bari mung-6, rice var. brri dhan48 and brri dhan57 were used for lentil, mungbean, t. aus and t. aman rice, respectively. in fp, rice var. brri dhan28 was used for boro rice and swarna for t. aman rice in both the years. in barind area, farmers normally used drought tolerant t. aman var. swarna. the trial was started with mungbean crop and completed two crop cycles in two consecutive years. the rates of the fertilizers for different crops were calculated using soil test value based (stb) on high yield goal as per frg (barc, 2012). the details of the varieties used and cultural operations adopted in different crops are given in table 3. for mungbean and lentil, all the inorganic fertilizers were applied at the time of final land preparation. in case of t.aus and t. aman rice, all the fertilizers except urea were applied as basal. urea was applied as top dressing in three equal splits at 10, 25 and 40 days after transplanting. all the crops were harvested at maturity from five spots with an area of 6.0 m2 each. data on yield of various crops in sequences were recorded and converted to ton per hectare. the data of fp was recorded from adjacent farmers’ plots. total system productivity was calculated as summation of individual (component) crop yield of each cropping cycle. the productivity of crop sequences was compared by calculating their economic rice equivalent yield (rey) using formula given by ahlawat and sharma (1993), where, productivity and nutrient balance 107 rey= yield of each crop (t ha-1) x economic value of respective crop (tk t-1) price of rice grain (tk t-1) marginal benefit cost ratio (mbcr) the economic analysis was done following the method suggested by cimmyt (1988). the mbcr can be computed as the marginal value product (mvp) over the marginal value cost (mvc). it can be computed as mvp (over control) mbcr = ------------------------ mvc (over control) apparent nutrient balance apparent nutrient balance was estimated considering the total amount of nutrient added to the soil through different sources and the total amount of nutrient uptake by the crop(s) (crops grain and their straw) each year. this calculation was valid particularly for p and k while calculating n balance, a 30% n loss have been assumed through different losses (like leaching, denitrification and volatilization loss etc). apparent nutrient balance was expressed in kg ha-1 yr1. the mean annual apparent n balance for the total pattern was calculated using the following formula: xa = (xf+ xr+ xi+ xb+xcri) xrem where xa = apparent gain (+) or loss (-) of n (kg ha-1) xf = n added through inorganic sources (kg ha-1) xr = n added through rainfall (kg ha-1) xi = n added through irrigation water (kg ha-1) xb= n added through bnf (kg ha-1) xcri= n added through crop residue incorporation (kg ha-1) xrem= n removed by crops and loss through different systems (kg ha-1). apparent n balances were calculated from sequences. the annual apparent p or k balance was calculated using the following simple equation: ya = (yf+ yr+ yi +ycri) yrem where ya = apparent gain (+) or loss (-) of nutrient (p or k) (kg ha-1) yf = nutrient (p or k) added through inorganic sources (kg ha-1) yr = nutrient (p or k) added through rainfall (kg ha-1) yi = nutrient (p or k) added through irrigation water (kg ha-1) ycri= nutrient (p or k) added through crop residue incorporation (kg ha-1) yrem= nutrient (p or k) removed by crops through different systems (kg ha-1). grain and straw samples of different crops were analyzed in the srdi laboratory, shyampur, rajshahi determine the concentration of n, p and k. the data were analyzed statistically with open source software r (r core team, 2017). table1. details of cultural practices adopted for different crops in field experiments 108 hossain et al. treat. crop seed rate (kg ha-1) spacing (cm) date of sowing / planting date of harvesting rate of fertilizer application (kg ha-1) n p k s zn b ip (improved pattern) lentil 45 broadcast 5-7 nov. 22-28 feb. 23 18 20 1.0 mungbean 30 broadcast 1-5 march 5-10 may 20 15 16 1.0 t.aus 40 20 x 15 15-20 may 5-10 august 80 15 30 12 2 t.aman 40 20 x 15 10-15 august 1-5 nov. 80 15 30 12 2 fp (farmers practice) boro 50 20 x 15 25-30 january 15-20 may 100 15 30 10 2 t.aman 40 20 x 15 15-20 july 1-7 nov. 75 12 26 10 table 2. chemical properties of soils (0-15 and 15-30 cm depth) of the experimental field after two cycle at fsrd site, kadamshahar, godagari depth (cm) ph organic matter (%) k total n (%) p s b zn meq /100g soil micro gram/g soil 0-15 7.2 1.1 0.21 0.07 15.6 6.2 0.19 0.18 15-30 7.8 0.87 0.21 0.05 7.8 10.6 0.17 0.29 mean 7.50 0.98 0.21 0.06 11.70 8.40 0.18 0.23 slightly alkaline low medium very low low low low very low results and discussion seed yield of mungbean in the late rabi season, mungbean was cultivated in only the ip. in 2015-16, mungbean seed yield was found 650 kg ha-1 and 720 kg ha-1 2016-17 (table 3). average over the years seed yield was 680 kg ha-1(table 3). mungbean was sown in early march for accommodating 4 crops in a year. yield of t. aus rice t. aus rice was cultivated in the ip while fp remained fallow. the t. aus yield was found higher 5.50 t ha-1 in 2015-16 than in 2016-17 (4.7 t ha-1) (table 3). average grain yield was 5.10 t ha-1 and straw yield was 6.47 t ha-1 (table 3). table 3. average yield (t ha-1) and rey (t ha-1) of different cropping pattern during 2015-16 and 2016-17 cp average yield (t ha-1) during 2015-16 and 2016-17 rey (t ha-1) % increase yield mungbean t. aus t. aman lentil / boro grain straw grain straw grain straw grain straw ip 0.68 1.45 5.1 6.47 3.37 5.21 4.63 (1.05) 1.15 15.01 46.29 fp 4.8 6.1 5.46 6.66 10.26 t-test ** ** ** ** ** nb. value in parenthesis indicating lentil yield; ** indicating significant in 1%; value in parenthesis indicating lentil yield ; price of rice -tk.17 kg-1, lentil-tk. 75 kg-1 and mungbeantk. 50 kg-1 grain yield of t. aman rice productivity and nutrient balance 109 grain yield of t.aman rice was found higher from fp (av. 4.80 t ha-1) in both years. in second year, yield of t. aman rice was higher than first year (table 4). this yield was mainly due to the variation in yield attributes. it was observed that the yield components (number of panicle hill-1 and grains panicle-1) were higher in fp which ultimately increased grain yield compared to ip and straw yield of 6.10 t ha-1. the ip gave 3.37 and 5.21 t ha-1 grain and straw yield, respectively. the sterility percentage was higher which ultimately resulted to lower yield. table 4. average p uptake (kg ha-1 yr-1) by grain and straw of crops and system in response to cropping pattern in 2015-16 and 2016-17 cp mungbean t. aus t. aman lentil / boro system grain straw grain straw grain straw grain straw grain straw total ip 3.74 7.97 15.3 8.41 18.53 6.77 3.15 2.65 40.72 25.8 66.52 fp 14.4 7.93 16.38 8.66 30.78 16.59 47.37 rabi crops (lentil and boro) in rabi season, lentil was cultivated in ip while boro rice in fp. for comparison, the economic yield of lentil was converted to rice equivalent yield (rey). the two-year average rey tended to be lower (4.63 t ha-1) in ip than that of fp (5.46 t ha-1) (table 3). in barind area, lentil yield is low due clay type soil, drought etc.. higher lentil yield was observed in 2nd year than 1st year (table 3). rice equivalent yield the ip recorded higher rey (15.01 t ha-1) than that of fp (10.26 t ha-1). total productivity increased by 46.29% in ip over fp (table 6). the ip took 345 days for its cycle while 215 days in fp (table 3).several scientists also reported that cropping sequences employing a summer grain legume produced significantly higher rey than the rice-rice sequence (singh et al., 2011; chauhan et al., 2012; singh et al., 2014). economic analysis cropping pattern attributed a remarkable impact on variable cost, gross return, gross margin and marginal benefit cost ratio (mbcr) (table 5). in general, four crop based pattern markedly enhanced the variable cost. from two years result showed that ip had higher cultivation cost (tk. 1,30,750 ha-1) than fp (tk. 96,600 ha-1). annual cost of cultivation increased with increasing cropping intensity, with the triple or more-cropping system incurring considerable higher costs than the double-cropping system primarily due to cost of fertilizer, labour and plant protection (biswas et al., 2006; singh et al., 2011, hossain et al., 2016b). ip had higher gross return (tk. 2,65,500 ha-1) and gross margin (tk. 1,34,750 ha-1) than fp. the mbcr was 1.38 in ip over fp. this was mainly due to the production potential accompanied with good monetary returns of components crops (lentil and t. aus rice). on the other hand fp gave lower gross return (tk.183990) and gross margin (tk. 87390 ha-1). table 5. economic analysis as influenced by four crop-based cropping pattern in average of 2015-16 and 2016-17 cp field duration of crop sequence (day) gross return (tk. ha-1) cultivation cost (tk. ha-1) gross margin (tk. ha-1) mbcr ip 345 265500 130750 134750 1.38 fp 215 183990 96600 87390 input 110 hossain et al. urea: 16 tk kg-1, tsp: 22 tk kg-1, mop: 15 tk kg-1, gypsum: 6 tk kg-1, zinc sulphate: 120 tk kg-1, boric acid: 150 tk kg-1, rice seed: 35 tk kg-1, mungbean seed : 60 tk kg-1, lentil seed: 90 tk kg-1, powertiller (1 pass): 2250 tk ha-1, irrigation (1 time): 900 tk ha-1 and labour: 200 tk day-1(8 hours) output rice grain: 17.00 tk kg-1, lentil seed: 75tk kg-1, mungbean grain: 50tk kg-1 , ricestraw: 0.75 tk kg-1 changes in soil fertility there was no difference in the lower layer (15-30 cm depth) between initial soil and that after two crop cycle. minor change was observed in top soil (0-15 cm) after two crop cycle (table1 and table 2). after two years cycle, there was a very little change in soil ph compared to initial soil. the reduction in ph occurred possibly due to the production of organic acids from the decomposition of biomass of herbaceous legumes (mungbean and lentil). decreases in ph have also been reported in other studies with cropping systems (chadha et. al., 2009; hossain et al., 2016a). soil organic matter (som) in soil increased slightly due to legumes had been included. the inclusion of legumes as a residue retained in cropping sequences improves the som status (ali, 2003). similar to som the inclusion of legumes in ip improved soil n compared to the initial value. furthermore, the mungbean biomass added was rich in n, which might have accelerated nitrogen fixation by free-living organisms. compared with the initial value, the available p content of soil increased. in contrast to p, exchangeable k was depleted after two crop cycles, relative to initial soil. these results indicate that there was a higher uptake of k than the amount added, which may lead to a serious depletion of k in the long term. this result is supported by panaullah et al. (2006). similar to k, the available s decreased. available zn and b content showed an increasing trend after the two crop cycles. nutrient uptake and apparent balance nitrogen uptake and apparent balance mungbean was grown in ip, n uptake by mungbean grain (21.42 kg ha-1) and stover ( 23.20 kg ha-1) was almost similar though concentration of n is higher in grain than that of mungbean stover (table 5). lower seed yield of mungbean resulted to lower n uptake by mungbean grain. in ip, n uptake by t. aus grain and straw was 68.85 and 44.0 kg ha-1, respectively. nitrogen uptake by t. aman in ip is lower than that of fp. farmers normally grow long duration swarna variety. it produced higher yield resulted to higher n uptake. n uptake by grain in both aman rice varieties is higher than that of straw. in lentil, about 70% of total n uptake was recorded by lentil grain. however, average n uptake by lentil grain and straw was 36.12 and 13.80 kg ha-1, respectively. boro rice var. brri dhan28 in fp removed substantial amount of n where higher amount by grain (73.71 kg ha-1) than that straw (45.29 kg ha-1). cropping pattern had an effect on system level grain, straw and total n uptake (table 5). in system level, relatively higher amount of n was removed by grain in both the cropping patterns. the ip, which included four crops recorded more n uptake by grain and straw than those of fp. the ip (288.31 kg ha-1) showed the higher system level total n uptake than fp (225.28 kg ha-1) due to higher total biomass production. table 6. average n uptake (kg ha-1 yr-1) by grain and straw of crops and system in response to cropping pattern in 2015-16 and 2016-17 cp mungbean t. aus t. aman lentil / boro system grain straw grain straw grain straw grain straw grain straw total ip 21.42 23.2 68.85 44.0 45.49 35.43 36.12 13.8 171.88 116.43 288.31 productivity and nutrient balance 111 fp 64.8 41.48 73.71 45.29 138.51 86.77 225.28 apparent n balance was calculated as the difference between n inputs and n outputs. apparent n balance indicates that n variations were related primarily to applied n from different sources, crop n uptake and n losses. annual system-level n input for ip (lentil-mungbean -t.aus-t. aman rice) was greater than fp (boro–fallow−t.aman) (fig. 1). apparent n losses increased substantially with ip, demonstrating that n losses were proportional to the rate of fertilizer n. considering bnf and n losses, the ip had a negative n balance, which was -10.72 kg ha-1. however, fp showed more negative balance (-35.96 kg ha-1) than ip. fig. 1. average inputs, outputs and balance of n in response to cropping pattern in 2015-16 and 2016-17 phosphorus uptake and apparent balance generally p uptake is low by plant in compared to n and k. again, rice crop removed more p than legume crops. in ip, p uptake by mungbean grain was (3.74 kg ha-1) and stover (7.97 kg ha1) (table 6). in ip, p uptake by t. aus grain and straw was 15.30 and 8.41 kg ha-1, respectively. p uptake by t. aman grain was higher in fp (18.53 kg ha-1) and lower in ip (14.4 kg ha-1). similar trend was observed for p uptake by t. aman rice straw. these results indicating that p uptake by crops resembled with those of crop yields.the p uptake was almost equal for grain (3.15 kg ha-1) and straw (2.65 kg ha-1) in lentil. the p uptake by boro rice grain (16.38 kg ha-1) was found higher than boro rice straw (8.66 kg ha-1).in system level, total p uptake was greater in ip (66.52 kg ha-1) than fp (47.37 kg ha-1). 396.55 270.46 407.27 306.42 -10.72 -35.96-100 0 100 200 300 400 500 ip fp input removal balance n (k g ha -1 yr -1 ) 112 hossain et al. fig. 2. average inputs, outputs and balance of p in response to cropping pattern in 2015-16 and 2016-17 system-level total p input was lower in fp and higher in ip, because the later pattern received more p through fertilizer and crop residue incorporation (fig. 2). the fp showed negative p balance (-17.69 kg ha-1) indicating p doses were insufficient to maintain the crop productivity for long run. however, the pattern ip got a positive balance, which was 26.65 kg ha-1. rijpma and jahiruddin (2004) also reported that the nutrient balance for p is slightly negative in bangladesh soils potassium uptake and apparent balance k uptake by mungbean grain (10.4 kg ha-1) was found lower than that of mungbean stover (31.17 kg ha-1) which is only grown in ip (table 7). in ip, k uptake by t. aus grain and straw were 15.81and 110.0 kg ha-1, respectively. k uptake by t. aman straw was higher (103.7 kg ha1) in fp and lower (88.57 kg ha-1) in ip. in case of t.aman grain k uptake was found also higher in fp (14.88 kg ha-1) and lower in ip (10.45 kg ha-1). long duration t. aman rice variety accumulated higher amount of k.k uptake was recorded similar in grain (11.55 kg ha-1) and straw (12.54 kg ha-1) in lentil. k uptake by boro rice straw was found much higher (113.22 kg ha-1) than boro rice grain (16.93 kg ha-1).the ip removed more k than fp. about 85% of k was removed by straw. system-level input k was lower in fp and higher in ip. apparent annual balance of k differed due to cropping patterns (fig. 3). the balance was consistently negative being higher in fp (-170.90 kg ha-1) and lower in ip (-121.68 kg ha-1) sequence. these results are comparable with singh et al., 2004; panaullah et al., 2006). 93.17 29.68 66.52 47.37 26.62 -17.69 -40 -20 0 20 40 60 80 100 ip fp input uptake balance p (k g ha -1 yr -1 ) productivity and nutrient balance 113 fig. 3. average inputs, outputs and balance of k in response to cropping pattern in 2015-16 and 2016-17 table 7. average k uptake (kg ha-1yr-1) by grain and straw of crops and system in response to cropping pattern in 2015-16 and 2016-17 cp mungbean t. aus t. aman lentil/boro system grain straw grain straw grain straw grain straw grain straw total ip 10.4 31.17 15.81 110.0 10.45 88.57 11.55 12.54 48.21 242.28 290.49 fp 14.88 103.7 16.93 113.22 31.81 216.92 248.73 note: ip =mungbean– t. aus -t. aman rice-lentil; fp =boro rice–fallow–t. aman rice conclusion the results of the study indicated that existing cropping pattern, boro – fallow-t. aman could be improved with four crops pattern such as lentil-mungbean -t.aus-t.aman rice in the high barind tract of bangladesh. the improved pattern, lentil – mungbean -t.aus-t.aman rice is superior and viable over the existing pattern, boro – fallow-t. aman rice cropping pattern in respect of system productivity, profitability and soil fertility. references ahlawat, i. p. s., sharma, r. p. 1993. agronomid terminology. 3rd edition. new delhi: indian soci. agron. ali, m. 2003. role of legumes in cropping systems in the indo-gangetic plains of india. in: addressing resource conservation issues in rice-wheat systems of south asia. ricewheat consortium for the indo-gangetic plains, cimmyt. nasc complex, new delhi110012, india. pp. 210-214. barc (bangladesh agricultural research council) 2012: fertilizer recommendation guide. barc, farmgate, dhaka 1215, bangladesh. bbs (bangladesh bureau of statitics) 2016. statistical yearbook of bangladesh (31st edition), bbs, statistics &informatic division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. 168.83 97.77 290.49 248.73 -121.68 -150.9-200 -100 0 100 200 300 400 ip fp input uptake balance k (k g ha -1 yr -1 ) 114 hossain et al. biswas, b., d.c. ghosh,m. k.dasgupta, n. trivedi, j. timsina anda.dobermann. 2006. integrated assessment of cropping systems in the eastern indo-gangetic plain. field crops res. 99:35–47. chadha, m.l., t. s. bains, h.s. sekhon and s.k. sain. 2009. short duration mungbean for diversification of rice–wheat system. milestones in food legume research ii— the peninsular region. kanpur, 151–177. cimmyt (international maize and wheat improvement center). 1988. from agronomic data to farmer recommendations: an economic training manual. cimmyt, mexico, d. f. 79 p. hossain, m.s., a. hossain,m.a. r.sarkar, m.jahiruddin, j. a. teixeira da silva, m. israil hossai,. 2016a. productivity and soil fertility of the rice-wheat system in the high ganges river floodplain of bangladesh is influenced by the inclusion of legumes and manure. agric. ecosyst. environ. 218, 40–52. doi:http://dx.doi.org/ 10.1016/j.agee.2015.11.017. hossain, m.s., m. a. r. sarkar, m. jahiruddin, a.k chaki and a. m. khan. 2016b. productivity and partial budget analysis in wheat-rice sequences as influenced by integrated plant nutrition system and legume crops inclusion. bangladesh j. agril. res. 41(1): 17-39 konrad, m., e.kirkby,h. kosengartenand t. appel. 2001. principles of plant nutrition (5thed.). kluwer academic publishers. isbn 1-4020-0008-1. panaullah, g. m., j. timsina, m. a. saleque, m. ishaque, a. b. m. b. u. pathan, d. j. connor, p. k.saha, m. a. quayyum, e. humphreys and c. a. meisner.2006. nutrient uptake and apparent balances for rice-wheat sequences. iii. potassium. j. plant nutr. 29: 173-187. rijpma, j. and m. jahiruddin. 2004. national strategy and plan for use of soil nutrient balance in bangladesh. a consultancy report, sffp, khamarbari, dhaka, 7-26 singh, r.k., j. s.bohra, t.nath, y. singhand k. singh. 2011. integrated assessment of diversification of rice–wheat cropping system in indo-gangetic plain. arch. agron. soil sci. 57 (5):489–506. tirol-padre, a., j. k.ladha, a. p.regmi, a. l.bhandari and k.inubushi.2007. organic amendment affect soil parameters in two longterm rice–wheat experiments. soil sci. soc. america j. 71: 442–52. worldometers. 2017. elaboration of data by united nations, department of economic and social affairs, population division. world population prospects: the 2017 revision. (mediumfertility variant). (www.worldometers.info on 5 october 2017). yu, y. l., l. hxue and l. z yang. 2014. winter legumes in rice crop rotations reduces nitrogen loss, and improves rice yield and soil nitrogen supply. agron. sustain dev. 34:633–40. bangladesh agron. j. 2019, 22(2): 11-24 physiological basis of salinity tolerance in foxtail millet s. akter​1*​, m.a. mannan​1​, m.a.a. mamun​1​ and m.s. islam​2 1​department of agronomy,​ 2​department of soil science bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding e-mail: mannanbsmrau@yahoo.com (received: ​17 december 2019,​ accepted: ​04 january 2020​) keywords:​ physiology, salinity, tolerance, foxtail millet abstract a pot experiment was conducted to study the effects of salt stress on physiological parameters associated to salinity tolerance in foxtail millet plant in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh during march to may, 2018. four foxtail millet genotypes namely i) bd-881 ii) bd-897 iii) bd-878 and iv) bari kaon-1 were grown and each pot was irrigated using three levels of saline water viz. control (tap water), 60 mm saline water and 120 mm saline water. results indicated that genotypic variability was profound in salinity tolerance in foxtail millet. the leaves of bd-878 maintained higher water content, higher accumulation of proline, and lower accumulation of malondialdehyde (mda) as well as less reduction of chlorophyll compared to other genotypes studied. bd-878 also showed relatively higher salinity stress tolerance, while bd-897 was susceptible in relation to yield. higher salinity tolerance in bd-878 was associated with higher relative leaf water and chlorophylls with accumulation of higher amount of proline and lower accumulation of malondialdehyde content. introduction the changes foreseen under climate change scenarios are the changes in the pattern of rainfall, rather than the quantum, leading to long spells of drought and spells of water-logging of the soils as well as salinity. foxtail millet is considered to be an ideal crop for the changing climate due to its short duration, high photosynthetic efficiency, nutritional richness and low incidence of pest and diseases (vetriventhan ​et al​., 2012) and has been reported to have comparable tolerant level to drought (doust ​et al​., 2009) and salinity (kafi ​et al​., 2009). foxtail millet can be a potential crop for salt affected soils due to its high level of tolerance to salinity (maas, 1985) and the salt ‘escape’ potential due to its short growing duration. salt stress induces several morphological, physiological, biochemical and molecular responses in several crop plants, which would help them to adapt to such limiting environmental conditions (arora ​et al., ​2002). it inhibits the photosynthesis of plants, causes changes of chlorophyll contents and damages the photosynthetic apparatus (escuredo ​et al., 1998). osmotic adjustment is the decrease of osmotic potential by the active accumulation of organic as well as inorganic solutes within the cells. high concentrations of inorganic ions become detrimental to cellular metabolism and must be sequestered in the vacuole. in order to keep osmotic balance, specific types of organic molecules (such as soluble sugars, betains, proline etc) are accumulated in the cytoplasm. those compounds protect plants 12 akter et al. against stresses by cellular adjustment through the protection of membranes integrity and enzymes stability (farooq ​et al., ​2009). these compounds are termed as compatible solutes, because they can be accumulated in high concentrations without impairing normal physiological function. so, aiming of this research work was to analyze the changes of morpho-physiological parameters that are associated with the salinity tolerance in foxtail millet as well as to study the effects of salinity on dry matter accumulation and yield of foxtail millet. materials and methods the experiment was conducted at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh. the experimental site is the center of madhupur tract (aez 28) (24.09​ο n latitude and 90.26​ο e longitudes) at 8.4 m above the mean sea level. the experiment was carried out employing 4 foxtail millet genotypes namely i) bd-881 ii) bd-897 iii) bd-878 and iv) bari kaon-1. the plants were grown in plastic pots of 24 cm diameter × 30 cm height in size filled with soil inside plastichouse under natural light during march to may, 2018. the soil used in the pot was clay loam in texture and poor fertility status. the ph of the soil was 7.1, organic carbon0.60%, total n0.05%, available p 0.08 mg/100 g dry soil, exchangeable k0.33 cmol​c ​kg​-1 ​dry soil and cec14.58 cmol​c ​kg​-1 ​dry soil. compost (​1​/4 th of the soil volume) and 0.27-0.28-0.20 g of urea, triple super phosphate and muriate of potash per pot for supplying n, p​2​o​5 and k​2​o, respectively were incorporated uniformly into the soil. the compost was made mostly from cow dung which contained 0.8% n, 0.6% p​2​o​5 ​and 1.0% k​2​o on dry weight basis. ten to fifteen bold seeds were sown in each plastic pot containing about 12 kg air dried soil. after seedling establishment, six uniform and healthy plants were allowed to grow in each pot. three levels of salt solution viz. i) tap water (control) ii) 60 mm salinity and 120 mm salinity were applied from 14 days after sowing to maturity. normal management practices were applied for all the treatments. the experiment was conducted with completely randomized design (crd) with three replications. the plant height and total dry weight (stem +leaf) were measured at 20 and 40 days after salt imposition (dasi). leaf water content, proline, melondialdehyde (mda) content and chlorophyll content were measured at flowering stage. the leaf water content (rwc) was measured using the formula: [(fw ​˗ dw)/(tw ​˗ dw)] × 100 where, tw = turgid weight of the leaf, fw = fresh weight of the leaf, dw = dry weight of the leaf. proline, melondialdehyde (mda) content and chlorophyll content was measured according to bates ​et al​. (1973), health & packer (1968) and witham ​et al. (1986), respectively. at maturity two plants were collected from each pot, and tiller number / plant, panicle number / plant, panicle weight / plant and seed yield / plant were recorded. data of salinity stress (60 mm and 120 mm) were compared with those in control (non saline water) treatment in order to understand the relative growth reduction of the individual plant part. the recorded data on various parameters were statistically analyzed by “cropstat”. the treatment means were compared by least significance difference (lsd) test at 5% level of significance (gomez & gomez, 1984). results and discussion plant height the effect of salt stress on plant height was statistically significant at 20 and 40 days after salt imposition (table 1). at 20 days, the plant height under control condition was the highest in bd-897, while the lowest was in bari kaon-1. at 60 mm saline condition the highest plant height was recorded in bd-897 and the lowest was in bari-kaon-1. relative (per cent of physiological basis of salinity tolerance in foxtail millet 13 control) plant height of the genotypes ranged from 91.87% to 96.44%. highest relative plant height was obtained from genotype bari kaon-1 (96.44%), followed by bd-878 (96.04%), and bd-897 (91.94%) and it was lowest in bd-881 (91.87%). at 120 mm saline condition the highest plant height was recorded with bd-897 and the lowest was in bari-kaon-1. relative (per cent of control) plant height of the genotypes ranged from 84.88% to 87.09%. highest relative plant height was obtained from genotype bd-878 (87.09%), followed by bari-kaon-1 (86.67%) and bd-881 (84.98%) and it was lowest in bd-897 (84.88%). plant height reduction due to salinity was lower in bd-878 (12.91%) while that was higher in bd897 (15.12%). after 40 days, the highest plant height was recorded in bd-897 and the lowest was demonstrated from bari kaon-1 under control condition. at 60 mm saline condition the highest plant height was recorded with bd-878 and the lowest was in bari kaon-1. relative (per cent of control) plant height of the genotypes ranged from 85.41% to 91.10%. highest relative plant height was obtained from genotype bd-878 (91.10%), followed by bd-897 (86.90%) and bd-881 (86.71%) and it was lowest in bari kaon-1 (85.51%). at 120 mm saline condition the highest plant height was recorded with bd-878 and the lowest was in bari kaon-1. relative (per cent of control) plant height of the genotypes ranged from 70.12% to 75.95%. highest relative plant height was obtained from genotype bd-878 (75.95%), followed by bd-881 (73.08%) and bari-kaon-1 (72.22%) and it was lowest in bd-897 (70.12%). plant height reduction due to salinity was lower in bd878 (24.05%), while that was higher in bd-897 (29.88%). therefore, bd-878 showed relatively higher salinity tolerance in relation to plant height than other genotypes studied. the lower height in the plants under salinity occurred, probably due the aba action, in which it is produced in the cells under water stress condition and this way inhibit the cell division and / or dna synthesis. similar results on the height reduction in plant under stress were described by lacerda ​et al. ​(2003) working with genotypes of ​sorghum bicolor​ under salt stress. table 1. plant height (cm) of foxtail millet genotypes as affected by salinity at different days after salt imposition (dasi) genotype s 20 dasi 40 dasi control 60 mm salinity 120 mm salinity control 60 mm salinity 120 mm salinity bd881 135.33​±​78.13* 124.32​±​71.78 (91.87) 115.00​±​66.40 (84.98) 195.6​±​8.19 169.67​±​4.67 (86.71) 143​±​4.93 (73.08) bd897 136.67​±​78.90 125.65​±​72.55 (91.94) 116.00​±​66.97 (84.88) 208.67​±​2.72 181.33​±​3.52 (86.90) 146.33​±​2.8 (70.12) bd878 126.33​±​72.94 121.30​±​70.05 (96.04) 105.67​±​61.01 (87.09) 202.33​±​2.84 184.33​±​4.48 (91.10) 153.67​±​2.72 (75.95) bari kaon-1 75.00​±​43.30 72.33​±​41.76 (96.44) 65​±​37.53 (86.67) 96​±​2.08 82​±​2.89 (85.41) 69.33​±​3.18 (72.22) lsd​(0.05) 1.10 2.05 cv (%) 22.86 31.12 * indicate se value, values in parenthesis indicate per cent of control. studies carried out by wang (2005) revealed that the aba induce the gene expression that codify the inhibited protein of the cyclin-dependent activity (ickl), coinciding with the results found by jakoby ​et al. (2006) on extreme important of this metabolic in cell division process and consequently development and growth of plant. total dry matter weight 14 akter et al. the effect of salt stress on total dry weight (leaf + stem) was statistically significant at 20 and 40 days after salt imposition (table 2). at 20 days, the total dry weight under control condition was the highest in bd-878, while the lowest was in bari kaon-1. at 60 mm saline condition the highest total dry weight was recorded with bd-878 and the lowest was in bari-kaon-1. relative (per cent of control) total dry weight of the genotypes ranged from 70.73% to 82.88%. highest relative total dry weight was obtained from genotype bd-878 (82.88%), followed by bd-881 (79.70%), and bd-897 (73.66%) and it was lowest in bari kaon-1 (70.73%). at 120 mm saline condition the highest total dry weight was recorded with bd-897 and the lowest was in bari kaon-1. relative (per cent of control) total dry weight of the genotypes ranged from 53.60% to 73.90%. highest relative total dry weight was obtained from genotype bd-878 (73.90%), followed by bari-kaon-1 65.70%) and bd-897 (65.34%) and it was lowest in bd-881 (53.60%). total dry weight reduction due to salinity was lower in bd-878 (73.90%) while that was higher in bd-(881 53.60%). after 40 days, the highest total dry weight was recorded in bd-881 and the lowest was demonstrated from bari kaon-1 under control condition. at 60 mm saline condition the highest total dry weight was recorded with bd-878 and the lowest was in bari kaon-1. relative (per cent of control) total dry weight of the genotypes ranged from (70.44% to 86.92%). highest relative total dry weight was obtained from genotype bd-878 (86.92%), followed by bd-881 (78.16%) and bd-897 (72.72%) and it was lowest in bari kaon-1 (70.44%). table 2. total dry weight (g) of foxtail millet genotypes as affected by salinity at different days after salt imposition (dasi) genotypes 20 dasi 40 dasi control 60 mm salinity 120 mm salinity control 60 mm salinity 120 mm salinity bd881 11.43​±​6.60* 9.11​ ±​5.26 (79.70) 6.13​±​3.54 (​53.60​) 47.01​±​8.71 36.74​±​3.60 (78.16) 29.89​±​2.58 (63.58) bd897 11.59​±​6.69 8.54​±​4.93 (73.66) 7.57​±​4.37 (​65.34​) 45.31​±​3.15 32.97​±​4.12 (72.72) 24.5​±​2.30 (54.06) bd878 12.19​±​7.04 10.10​±​5.83 (82.88) 7.47​±​4.31 (​73.90​) 45.21​±​8.08 39.30​±​1.87 (86.92) 34.93​±​1.51 (77.26) bari kaon-1 8.75​±​5.05 6.19​±​3.57 (70.73) 5.75​±​3.32 (​65.70​) 27.17​±​0.95 19.14​±​1.50 (70.44) 15.78​±​1.60 (58.06) lsd​(0.05) 0.15 0.10 cv (%) 25.50 30.94 * indicate se value, values in parenthesis indicate per cent of control. at 120 mm saline condition the highest total dry weight was recorded with bd-878 and the lowest was in bari-kaon-1. relative (per cent of control) total dry weight of the genotypes ranged from 54.06% to 77.26%. highest relative total dry weight was obtained from genotype bd-878 (77.26%), followed by bd-881 (63.58%) and bari-kaon-1 (58.06%) and it was lowest in bd-897 (54.06%). total dry weight reduction due to salinity was lower in bd-897 (45.94%) while that was higher in bd-878 (22.74%). stress condition caused significant decrease in plant growth. these results were in harmony with abass and mohamed (2011) who reported that the plant growth parameters of common bean (shoot and root length, fresh and dry weights of shoots and roots) decreased significantly with increasing drought stress as compared with control plants. such decline in shoot and root growth in response to stress might be due to either decrease in cell elongation, cell turgor, cell volume and eventually cell growth (banon ​et al.​, 2006), and/or due to blocking up of xylem and phloem vessels thus hindering any translocation through (lavisolo and schuber, 1998). physiological basis of salinity tolerance in foxtail millet 15 leaf water content the effect of salt stress on leaf water was statistically significant (figure 1). at 60 mm saline condition relative (per cent of control) leaf water of the genotypes ranged from 69% to 87%. highest relative leaf water was obtained from genotype bd-878 (87%), followed by bari kaon-1 (79%), and bd-881 (78%) and it was lowest in bd-897 (69%). at 120 mm saline condition relative (per cent of control) leaf water content of the genotypes ranged from 63% to 84%. highest relative leaf water was obtained from genotype bd-878 (84%), followed by bari-kaon-1 (75%) and bd-881 (68%) and it was lowest in bd-897 (63%). the reduction in leaf rwc (%) was provoked by the water deficiency in soil, in which the water stress due to salinity effect simulated artificially in this experiment cause as direct consequence changes in lrwc, because during the transpiration process and photosynthesis occur water loss through of the stomata and the assimilation / reposition rate is strongly affected, occurred probably decrease of the conductance stomatal for reduce the water loss to the atmosphere (verslues ​et al., ​2006​). velu and palanisami (2001) also reported that water stress significantly reduced relative water content of the plant. fig. 1. relative leaf water content of four foxtail millet genotypes as affected by salinity. chlorophyll a the effect of salt stress on chlorophyll content was statistically significant (figure 2). at 60 mm saline condition relative (per cent of control) leaf water of the genotypes ranged from 69% to 85%. highest relative chlorophyll a content was obtained from genotype bari kaon-1 (85%), followed by bd-878 (82%) and bd-881 (75%) and it was lowest in bd-897 (69%). at 120 mm saline condition relative (per cent of control) chlorophyll a content of the genotypes ranged from 60% to 75%. highest relative leaf water was obtained from genotype bd-878 (75%), followed by bari-kaon-1 (70%) and bd-897 (61%).and it was lowest in bd-881 (60%). 16 akter et al. fig. 2. relative chlorophyll a content of four foxtail millet genotypes as affected by salinity. chlorophyll b the effect of salt stress on chlorophyll b was statistically significant (figure 3). at 60 mm saline condition relative (per cent of control) chlorophyll b content of the genotypes ranged from 47% to 78%. highest relative leaf water was obtained from genotype bd-878 (78%), followed by bd-881 (76%), bd-897 (60%) and it was lowest in bari kaon-1 (47%). at 120 mm saline condition relative (per cent of control) chlorophyll b content of the genotypes ranged from 24% to 63%. highest relative leaf water was obtained from genotype bd-878 (63%), followed by bd-881 (57%), bd-897 (57%) and it was lowest in bari-kaon-1 (24%). fig. 3. relative chlorophyll b content of four foxtail millet genotypes as affected by salinity. physiological basis of salinity tolerance in foxtail millet 17 total chlorophyll content the effect of salt stress on total chlorophyll content was statistically significant (figure 4). at 60 mm saline condition relative (per cent of control) total chlorophyll content of the genotypes ranged from 61% to 80%. highest relative total chlorophyll was obtained from genotype bd-878 (80%), followed by bd-881 (75%) and bd-881 (75%) and it was lowest in bd-897 (66%) bari kaon-1 (61%), at 120 mm saline condition relative (per cent of control) leaf chlorophyll content of the genotypes ranged from 41% to 70%. highest relative leaf total chlorophyll was obtained from genotype bd-878 (70%), followed by bd-897 (60%) and bd-881 (59%) and it was lowest in bari-kaon-1 (41%). the reduction of the total chlorophyll due to salt stress was lower in bd-878 (30%), while that was higher in bari kaon-1 (59%). abass and mohamed (2011) who reported that photosynthetic pigments contents in leaves of common bean plants were highly significantly decreased with increasing the level of drought stress. sairam ​et al​. (2002) showed higher decrease in pigment contents of wheat genotypes under salinity at the three stages. the observed decrease of chlorophyll content in the plants grown under saline conditions may be attributed to both of the increased degradation and the inhibited synthesis of that pigment (garsia ​et al.​, 2002). the reduction in chlorophyll content under stress has been considered a typical symptom of oxidative stress and may be the result of pigment photo-oxidation and chlorophyll degradation. the decrease in the photosynthetic activity under stress may be due to stomatal or non-stomatal mechanisms. stomata closure is one of the first responses to drought stress which result in declined rate of photosynthesis. the drought induced reduction in the chlorophyll content could be attributed to loss of chloroplast membranes, excessive swelling, and distortion of the lamellae vesiculation and the appearance of lipid droplets. it was also reported that this pigment was sensitive to increasing environmental stress (terzi ​et al.​, 2010). the decrease in total chlorophyll content may have resulted from a decrease in leaf water status in the soybean. 18 akter et al. fig. 4. relative total chlorophyll content of four foxtail millet genotypes as affected by salinity. proline content the effect of salt stress on proline content was statistically significant (figure 5). at 60 mm saline condition relative (per cent of control) proline content of the genotypes ranged from 124% to 157%. highest relative proline content was obtained from genotype bd-878 (157%), followed by bari kaon-1 (135%), and bd-897 (129%) and it was lowest in bd-881 (124%). at 120 mm saline condition relative (per cent of control) proline content of the genotypes ranged from 157% to 179%. highest relative proline content was obtained from genotype bd-878 (179%), followed by bari-kaon-1 (164%) and bd-897 (161%) and it was lowest in bd-881 (157%). the proline accumulation is a metabolic response characteristic of plants under abiotic stresses, it being showed the increase in this experiment because the free proline work as osmotic adjustor that objective reduce the negative effects provoked in the plants under adverse conditions zhu (2002). fig. 5. relative proline content of four foxtail millet genotypes as affected by salinity proline is known to play as an osmoprotectant in plants subjected to osmotic stresses resulted from drought and soil salinity. a positive correlation between proline accumulation and osmoticstress tolerance has been reported by muthulakshmi ​et al. (2013), abraham ​et al​. (2003), abdelhamid ​et al. (2013), khattab (2007), amirjani (2010), sadak and dawood (2014) and taie ​et al. (2013). remarkable increase in proline content under stress conditions could be due to changes in proline metabolism profile under salinity stress, with an increased expression of proline synthetic enzymes and breakdown of proline-rich protein (tewari and singh, 1991). according to kaouther ​et al​. (2012) investigations with chili pepper (​capsicum frutescens ) obtained results showing significant increase in proline in all cultivars with the physiological basis of salinity tolerance in foxtail millet 19 increase of salt concentration in irrigation water. the accumulation of osmolyte compounds is often proposed as a solution to overcoming the negative consequences of water deficits in crop production which has been proposed as an adaptive mechanism for drought and salt tolerance. indeed, osmolyte accumulation (oa) in plant cell results in a decrease of the cell osmotic potential and help in the maintenance of water absorption and cell turgor pressure, which might contribute to sustaining physiological processes, such as stomatal opening, photosynthesis and expansion growth (kaouther ​et al​., 2012). malondialdehyde (mda) content the effect of salt stress on melondialdehyde (mda) content was statistically significant (figure 6). at 60 mm saline condition relative (per cent of control) mda content of the genotypes ranged from 106% to 116%. highest relative mda content was obtained from genotype bd-881 (116%) followed by bd-897 (114%), and bari kaon-1 (112%) and it was lowest in bd-878 (106%). at 120 mm saline condition relative (per cent of control) mda content of the genotypes ranged from 107% to 119%. highest relative mda content was obtained from genotype bd-881 (119%), followed by bari-kaon-1 (116%), and bd-897 (110%) and it was lowest in bd-878 (106%). the relative mda content was significantly higher in saline condition than control in all the genotypes. the rise in mda content under stress conditions suggests that water/saline stress could induce membrane lipid peroxidation by means of ros (sairam ​et al., 2002). ​it is also generally accepted that the accumulation of mda, a measure of lipid peroxidation, is considered a potential marker of oxidative damage (jouve ​et al.​, 2003; ashraf, 2009; ashraf ​et al​., 2010). generally, mda concentration changes with increasing salt concentration e.g. in limonium bicolor, it decreased at 100 mm, while increased at 200 mm nacl indicating that l. bicolor plants were better protected from oxidative damage under saline regime (li, 2008). in the present investigation, the lower relative values of mda in bd-878 indicate that at cellular level this genotype is better equipped with efficient free radical quenching system that offers protection against oxidative stress. 20 akter et al. fig. 6. relative melondialdehyde content of four foxtail millet genotypes as affected by salinity. effect of salt stress on yield and yield contributing characters number of tiller the effect of salt stress on number of tiller/plant was statistically significant (table 3). at control condition, the tiller number was the highest in bd-878 (12.33), followed by bd-881 (9.33), bd-897 (9.00), while the lowest was in bari kaon-1 (8.67). at 60 mm saline condition the highest tiller number was recorded with bd-878 (10.33) and the lowest was in bbari kaon-1 (7.00). relative (per cent of control) tiller number of the genotypes ranged from 78.57% to 83.78%. highest relative tiller number was obtained from genotype bd-878 (83.78%), followed by bd-897 (81.48%), and bari kaon-1 (80.77%) and it was lowest in bd-881 (78.57%). at 120 mm saline condition the highest tiller number was recorded with bd-878 (7.00) and the lowest was in bd-881 (4.48)​. relative (per cent of control) tiller number of the genotypes ranged from 48.01% to 67.74%. highest relative tiller number was obtained from genotype bd-878 (67.74%), followed by bari-kaon-1 (57.69%) and bd-897 (55.56%) and it was lowest in bd-881 (48.01%). tiller number reduction due to salinity was lower in bd-881 (32.26%) while that was higher in bd-878 (51.99%). table 3. tiller number and panicle number of foxtail millet genotypes as affected by salinity genotypes tiller number plant​-1 panicle number-plant​-1 control 60 mm salinity 120 mm salinity control 60 mm salinity 120 mm salinity bd881 9.33 7.33 (78.57) 4.48 (48.01) 9.33 7.33 (78.57) 5.00 (53.57) physiological basis of salinity tolerance in foxtail millet 21 bd897 9.00 7.33 (81.48) 5.00 (55.56) 8.67 6.33 (73.08) 5.00 (57.69) bd878 12.33 10.33 (83.78) 7.00 (67.74) 8.00 7.00 (87.50) 6.00 (85.71) bari kaon-1 8.67 7.00 (80.74) 5.00 (57.69) 5.67 4.33 (76.47) 3.67 (64.71) lsd​(0.05) 2.61 2.13 cv (%) 20.0 20.0 values in parenthesis indicates percent of control number of panicle the effect of salt stress on number of panicle/plant was statistically significant (table 3). at control condition, the panicle number was the highest in bd-881 (9.33), followed by bd-897 (8.67), bd-878 (8.00), while the lowest was in bari kaon-1 (5.67). at 60 mm saline condition the highest panicle number was recorded with bd-878 (7.33) and the lowest was in bbari kaon-1 (4.33). relative (per cent of control) panicle number of the genotypes ranged from 73.08% to 87.50%. highest relative panicle number was obtained from genotype bd-878 (87.50%), followed by bd-881 (78.57%) and bari kaon-1 (76.47), and the lowest was in bd-897(73.08). at 120 mm saline condition the highest panicle number was recorded with bd-878 (6.00) and the lowest was in bari-kaon-1 (3.67). relative (per cent of control) panicle number of the genotypes ranged from 53.57% to 85.71%. highest relative panicle number was obtained from genotype bd-878 (85.71%), followed by bari-kaon-1 (64.71%) and bd-897 (57.69%) and it was lowest in bd-881 (53.57%). panicle number reduction due to salinity was lower in bd-881 (14.29%) while that was higher in bd-878 (46.43%). panicle weight the effect of salt stress on panicle weight (g/plant) was statistically significant (table 4). at control condition, the panicle weight was the highest in bari kaon-1 (8.00), followed by bd-878 (4.94), bd-897 (7.46), and the lowest was in bd-881 (4.44). at 60 mm saline condition the highest panicle weight was recorded with bari kaon-1 (5.59) and the lowest was in bd-881 (3.12). relative (per cent of control) panicle weight of the genotypes ranged from 42.78% to 85.48%. highest relative panicle weight was obtained from genotype bd-878 (85.48%), followed by bd-881 (70.26%), and bari-kaon-1. (69.86%) and it was lowest in bd-897 (42.78%). at 120 mm saline condition the highest panicle weight was recorded with bari-kaon-1 (2.34) and the lowest was in bd-881 (1.92). relative (per cent of control) panicle weight of the genotypes ranged from 27.71% to 54.05%. highest relative panicle weight was obtained from genotype bd-878 (54.05%), followed by bd-881 (43.29%) and bari-kaon-1(29.25) and it was lowest in bd-897 (27.71%). panicle weight reduction due to salinity was lower in bd-878 (45.95%) while that was higher in bd-897 (72.29%). seed yield the effect of salt stress on seed yield (g/plant) was statistically significant (table 4). at control condition, the seed yield was the highest in bd-897 (11.71), followed by bd-878 (9.51), bari kaon-1 (9.19), and the lowest was in bd-881 (9.10). at 60 mm saline condition the highest seed yield was recorded with bd-878 (7.60) and the lowest was in bd-897 (3.83). relative (per cent of control) seed yield of the genotypes ranged from 32.68% to 79.86%. highest relative seed yield was obtained from genotype bd-878 (79.86%), followed by bari kaon-1 22 akter et al. (67.30%) and bd-881 (59.08%) and it was lowest in bd-897 (32.68%). at 120 mm saline condition the highest seed yield was recorded with bd-897 (3.30) and the lowest was in bd-881 (1.01). relative (per cent of control) seed yield of the genotypes ranged from 11.13% to 28.21%. highest relative seed yield was obtained from genotype bd-897 (28.21%), followed by bd-878 (20.45%) and bari-kaon-1 (12.77%) and it was lowest in bd-881 (11.13%). seed yield reduction due to salinity was lower in bd897 (71.79%), while that was higher in bd-881 (88.87%). salinity induced yield reduction has been reported in many crop species, which depends upon the severity and duration of the stress period. salinity was also found to reduce the shoot length, number and size of spikes and the grain yield (hendawy ​et al​., 2012). table 4. panicle weight and seed yield of foxtail millet genotypes as affected by salinity genotypes panicle weight (g plant​-1​) seed yield (g plant​-1​) control 60 mm salinity 120 mm salinity control 60 mm salinity 120 mm salinity bd881 4.44 3.12 (70.26) 1.92 (43.29) 9.10 5.37 (59.08) 1.01 (11.13) bd897 7.46 3.19 (42.78) 2.07 (27.71) 11.71 3.83 (32.68) 3.30 (28.21) bd878 4.94 4.22 (85.48) 2.28 (54.05) 9.51 7.60 (79.86) 1.55 (20.45) bari kaon-1 8.00 5.59 (69.86) 2.34 (29.25) 9.19 6.19 (67.30) 1.17 (12.77) lsd​(0.05) 2.18 4.00 cv (%) 11.4 10.1 values in parenthesis indicates percent of control saline water irrigations with salinity increasing from 1 to 16 ds m​-1 had been noticed to linearly decrease seed and straw yield, harvest index and 1000 grain weights in foxtail millet and the harvested seeds from these treatments were found to germinate into normal seedlings (thimmaiah ​et al​., 1989). in the present study, the reduction in seed yield under salt stress was associated with dramatic decrease in all these yield components. conclusion based on the above results it may be concluded that bd-878 showed relatively higher salinity tolerance in respect of dry matter accumulation and yield compared to other genotypes studied. higher salinity tolerance in bd-878 was associated with better water relations and osmotic adjustment with accumulation of higher amount of proline. furthermore, under salinity conditions less damaged chlorophylls as well as lower accumulation of melondialdehyde content contributed to the higher salinity tolerance in bd-878 compared to other genotypes. acknowledgement the authors ​are grateful to ministry of science and technology, government of bangladesh for funding the research. physiological basis of salinity tolerance in foxtail millet 23 references abass, s.m. and h.i. mohamed. 2011. alleviation of adverse effects of drought stress on common bean (​phaseolus vulgaris ​l.) by exogenous application of hydrogen peroxide. bangladesh j. bot. 41: 75-8 abdelhamid, m.t., m.s.h. sadak, u.r.s. schmidhalte and a.k.m. el-saady. 2013. interactive effects of salinity stress and nicotinamide on physiological and biochemical parameters of faba bean plant. acta boil. colom. 18: 3-14. abraham, e., g. rigo, g. szekely, r. nagy, c. koncz and l. szabados. 2003. light dependent induction of proline biosynthesis by abscisic acid and salt stress is inhibited by brassinosteroid in arabidopsis. plant molecul. biol. 51: 363–372. amirjani, m.r. 2010. effects of salinity stress on growth, mineral composition, proline content, antioxidant enzymes of soybean. american j. physiol. 5: 350-360 ashraf, m. 2009. biotechnological approach of improving plant salt tolerance using antioxidants as markers. biotechnol. adv. 27: 84–93. ashraf, m., n.a. akram, r.n. arteca and m.r. foolad, 2010. the physiological, biochemical and molecular roles of brassinosteroids and salicylic acid in plant processes and salt tolerance. crit. rev. plant sci. 29: 162–190. arora, a., r.k. sairam and g.c. srivastava. 2002. oxidative stress and antioxidative systems in plants. curr. sci. 82: 1227-1238. banon, s., j. ochoa, j.a. franco, j.j. alarcon and m.j. sanchez-blanco. 2006. hardening of oleander seedlings by deficit irrigation and low air humidity. environ. expt. bot. 56: 36-43. bates, l., r.p. waldren and i.d. teare. 1973. rapid determination of free proline for water-stress studies. plant soil. 39: 205-207. doust, a.n., e.a. kellogg, k.m. devos and j.l. bennetzen. 2009. foxtail millet: a sequence-driven grass model system. plant physiol. 149: 137-141. escuredo, i.p., c. arrese-igor and m. becana. 1998. oxidative damage in pea plants exposed to water deficit or paraquat. plant physiol 116: 173-181. farooq, m., a. wahid, n. kobayashi, d. fujita and s.m.a. basra. 2009. plant drought stress: effects, mechanisms and management. agron. sustain. dev., 29: 185-212. garsia-sanchez, f., j.l. jufon, m. carvaial and j.p. syverstem. 2002. gas exchange, chlorophyll and nutrient contents in relation to na+ and cl– accumulation in ‘sunburst’ mandarin grafted on different rootstocks. plant sci. 162: 705-712. gomez, a. a. and a.a. gomez. 1984. statistical procedure of agricultural research. second edition. john wiley and sons. new york. health, r.l. and l. packer. ​1968. photoperoxidation in isolated chloroplasts. i. kinetics and stoichiometry of fatty acid peroxidation. archives biochem. biophy. 125​: ​189-198. hendawy, s.f., s.e. el-sherbeny, m.s. hussein and a.a. youssef. 2002. evaluation of some cultivars of foxtail plants under salinity conditions. j. appl. sci. res. 8​: ​620–627. jakoby, m.j., c. weinl, s. pusch, s.j. kuijt, t. merkle, n. dissmeyer and a. schnittger. 2006. analysis of the subcellular localization, function, and proteolytic control of the arabidopsis cyclin-dependent kinase inhibitor ick1/krp1. plant physiol. 141(4): 1293-1305. jouve, l., l. hoffmann and j.f. hausman. 2003. polyamine, carbohydrate, and proline content changes during salt stress exposure of aspen (​populus tremula l): involvement of oxidation and osmoregulation metabolism. plant biol. 6: 74–80. 24 akter et al. kafi, m., g.h. zamani and s.g.h. ghoraishi. 2009. relative salt tolerance of south khorasan millets. desert. 14: 63-70. kaouther, z., f.m, ben, f. mani and c. hannachi. 2012. impact of salt stress (nacl) on growth, chlorophyll content and fluorescence of tunisian cultivars of chili pepper (​capsicum frutescens​ l.). j. stress physiol. biochem.. 8: 236-252. khattab, h. 2007. role of glutathione and polyadenylic acid on the oxidative defense systems of two different cultivars of canola seedlings grown under saline conditions. australian j. basic appli. sci. 1: 323-334. lacerda, c.f.d., j. cambraia, m.a. oliva and h.a. ruiz. 2003. osmotic adjustment in roots and leaves of two sorghum genotypes under nacl stress. ​brazilian j. plant physiol. 15​(2): 113-118. lavisolo, c. and a. schuber. 1998. effects of water stress on vessel size xylem hydraulic conductivity in ​vitis vinifera ​l. j. expt. bot. 49: 693-700. li, y. 2008. kinetics of the antioxidant response to salinity in the halophyte ​limonium bicolour​. plant soil environ. 54: 493–497. maas, e.v. 1985. crop tolerance to saline sprinkling water. plant soil​. ​89: 273-284. muthulakshmi, s.m., g.s. gurulakshmi and s. rajathi. 2013. effect of salt stress on physiological and biochemical characteristics in ​solanum nigrum​ l. int. j. sci. res. 4: 12-20. sadak, m.s.h. and m.g. dawood. 2014. role of ascorbic acid and α tocopherol in alleviating salinity stress on flax plant (​linumusi tatissimum l.). j. stress physiol. biochem. 10: 93-111. sairam, r.k., k.v. rao and g.c. srivastava. 2002. differential response of wheat genotypes to long term salinity stress in relation to oxidative stress, antioxidant activity and osmolyte concentration. plant sci. 163: 10371046. taie, h., m.t. abdelhamid, m.g. dawood and r.m. nassar. 2013. pre-sowing seed treatment with proline improves some physiological, biochemical and anatomical attributes of faba bean plants under sea water stress. j. appl. sci. res. 9: 2853-2867. terzi, r., a. sağlam, n. kutlu, h. nar and a. kadıoğlu. 2010. impact of soil drought stress on photochemical efficiency of photosystem ii and antioxidant enzyme activities of ​phaseolus vulgaris ​cultivars. turk. j. bot​. ​34: 1-10. tewari, t. n. and b.b. singh. 1991. stress studies in lentil (​lens esculenta moench). plant soil. 136(2): 225-230. thimmaiah, s.k., d.p. viswanath, b.s. vyakarnahal and c.s. hunshal. 1989. effect of salinity on yield, seed quality and biochemical characteristics in ​setaria italica l. cereal chem. 66: 525-527. verslues, p.e., m. agarwal, s. katiyar​-​agarwal, j. zhu and k. zhu. 2006. methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status. ​the plant j. 45​(4): 523-539. velu, g. and k. palanisami. 2001. impact of moisture stress and ameliorants on growth and yield of sunflower. madras agric. j. 88(10/12): 660-665. vetriventhan, m., h.d. upadhyaya, c.r. anandakumar, s. senthilvel, h.k. parzies. a. bharathi, r.k. varshney and c.l.l. gowda. 2012. assessing genetic diversity, allelic richness and genetic relationship among races in icrisat foxtail millet core collection. plant gen. res​. 10: 214–223. wang, j. 2005. carbon​-​nanotube based electrochemical biosensors: a review. ​electro analysis: an int. j. dev. fund. prac. aspects electro analysis. 17​(1): 7-14. physiological basis of salinity tolerance in foxtail millet 25 witham, f.h., d.f. blaydes and r.m. devlin. 1986. chlorophyll absorption spectrum and quantitative determinations. in. exercise in plant physiology. second edition. boston, pp. 128-131. zhu, j.k. 2004. plant salt tolerance. trends plant sci. 6(2): 66-71. bangladesh agron. j. 2018, 21(2): 19-24 intercropping squash with maize under varying planting system j.a. chowdhury1, s.s. kakon1, a.a. begum1 and m.a.k. mian2 1senior scientific officer, agronomy division, bangladesh agricultural research institute, gazipur-1701 2principal scientific officer, agronomy division, bangladesh agricultural research institute, gazipur1701 *corresponding author, e-mail: jasminedaisy.bari@gmail.com (received: 7 november 2017, accepted: 9 april 2019) abstract the experiment was conducted at the research field of agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur during rabi seasons of 2014-15 and 2015-16 to find out the suitable planting arrangement of squash (var. bulam house) with maize (var. bari hybrid maize-9) as intercropping for higher productivity and economic return. seven treatment combinations viz. maize normal plating (75 cm  25 cm), maize normal plating (75 cm  25 cm) (100%) + 1 row squash (plant to plant 80 cm) (116%), maize paired row (37.5 cm  150 cm  37.5 cm) (100%) + 1 row squash (plant to plant 80 cm) (50%), maize paired row (100%) + 1 row squash (plant to plant 100 cm) (40%), maize paired row (100%) + 2 rows squash (plant to plant 80 cm) (100%), maize paired row (100%) + 2 rows squash (80%) (plant to plant 100 cm) and sole squash (100 cm × 80 cm) were tested. results showed that the highest grain yield of maize (9.47 t ha-1 in 2014-15 and 9.24 t ha-1 in 2015-16) and squash yield (28.19 t ha-1 in 2014-15 and 25.02 t ha-1 in 2015-16) were recorded in sole crop, respectively. maximum mean maize equivalent yield (19.39 t ha-1) was recorded in maize paired row (100%) + 2 row squash (plant to plant 80 cm) (100%) combination in both the year. the highest gross return (tk. 2,93,850 ha-1), gross margin (tk. 1,92,450 ha-1) and bcr (2.95) were also obtained from the same combinations. two years’ results revealed that maize paired row + 2 rows squash (plant to plant 80 cm) combination could be suitable for higher productivity and economic return. introduction bangladesh is a small country but food demand is higher due to high rate of plant population. in order to produce more food within a limited area, one of the most important options is to increase the cropping intensity through intercropping which was higher productivity per unit area of land (ahmed et al., 2013). intercropping is one of the cropping strategies that have been recognized to improve the food security situation and higher incomes for the farmers (mahfuza, 2012). it also helps to reduce weed populations, insect and pest infestation and risk of complete crop failure (islam et al., 2013). intercropping is a traditional practice in bangladesh but the important determinants in intercropping systems are the judicious choice of compatible crops with minimum inter-specific competition, suitable planting system or proportion of component crops (islam et al., 2004). production of vegetables grown under intercropping depends on the component of crops selected as well as row arrangements (lewis et al., 2003). maize is an important cereal crop and squash is also very promising vegetable. there is a scope to grow maize and squash as intercrop. in maize-squash intercropping system generally maximum yield of maize and bonus about:blank 22 chowdhury et al. yield of squash is desired. spatial arrangement, like sowing of maize in paired may allow more light to underneath squash for its better growth and productivity (shivay et al, 1999). moreover, higher density of squash may be accommodated in wider space in between paired rows of maize (islam, 2002). however, information relating spatial arrangement of maize in accordance with accommodation of different densities of squash intercropping system is scarce under bangladesh condition. so, this experiment was undertaken to find out suitable planting arrangement of squash intercrop with maize for getting higher productivity and economic return. materials and methods the experiment was conducted at the research field of agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur during rabi seasons of 2014-15 and 2015-2016. the treatments were t1: maize normal plating (75 cm  25 cm), t2: maize normal plating (100%) + 1row squash (plant to plant 80 cm) (116%), t3: maize paired row 37.5 cm /150 cm/ 37.5 cm (100%) + 1 row squash (plant to plant 80 cm) (50%), t4: maize paired row (100%) + 1row squash (plant to plant 100 cm) (40%), t5: maize paired row (100%) + 2 rows squash (plant to plant 80 cm) (100%), t6: maize paired row (100%) + 2 rows squash (80%) and t7: sole squash (100 cm  80 cm). the experiment was laid out in randomized complete block (rcb) design with 3 replications. the unit plot size was 4 m  4.5 m. maize var. bari hybrid maize-9 and squash (var. bulam house) were used as test crop. seeds of both crops were sown on 24 november, 2014 and 20 november, 2015. fertilizers were applied at the rate of 250-120-120-40-5 kg ha-1 npkszn + 10 t cowdung ha-1 for sole maize and intercrop treatments. half n and all other fertilizer was applied as basal. remaining n was applied at 15 and 35 days after sowing (das) in two equal splits. additional 40 kg ha-1 n was applied in intercropping treatment. in sole squash the crop was fertilized at the rate of 80-35-75-20-4-2 kg ha-1 npksznb + 20 t cowdung ha-1. chemical fertilizers were used in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid. intercultural operations like watering, weeding and pest control were done as and when required. squash was harvested during 21 january to 24 february in 2015 and 20 january to 16 february in 2016. maize was harvested on 22 april in 2015 and 25 april in 2016. yield components of both crops were taken from randomly selected 5 plants from each plot. yields of both the crops were taken from whole plot. land equivalent ratio (ler) values were computed from the yield data of the crops according to willey (1985). collected data of twocrops were analyzed statistically and the means were adjudged using least significant difference (lsd) test at 5% level. benefit-cost analysis was also done. maize equivalent yields were computed by converting yield of intercrops on the basis of prevailing market price of the individuals by using the formula of bandyopadhaya (1984). maize equivalent yield (mey) (kg ha-1) = m p .p.yi ss yim + where, yim = maize yield (kg ha-1) in intercropping. yis. = squash yield (kg ha-1) in intercropping pm = price of maize (tk kg-1) ps. = price of squash (tk kg-1) intercropping squash with maize under varying planting system 23 results and discussion performance of maize single cob weight, 1000grain weight and grain yield ha-1 of maize were significantly affected when grown in association with squash under different treatment combinations (table -1). higher single cob weight (251.27 gm in 2014-15 and 258.2 gm in 2015-16) was observed in sole maize followed by mpr + 1 row squash (40 %) and the lowest (181.27 gm in 2014-15 and 208.7 gm in 2015-16) in mnp (100%) + 1 row squash (116%) treatment combination. similar trend was observed in 1000-seed weight in both years. the value of these parameters was reduced with increasing in squash population. the lower value of those parameters might be due to increased plant population as well as more inter specific competition. the highest grain yield (9.47 t ha-1 in 2014-15 and 9.24 t ha-1 in 2015-16) was obtained from sole maize might be due to higher single cob weight and 1000-grain weight. similar results were also reported by uddin et al., 2009. among the intercropped combinations, the maximum grain yield (9.01 t ha-1 in 2014-15 and 8.3 t ha-1 gm in 2015-16) of maize was recorded when it was grown as paired row (100%) + 1 row squash (40%) due to less inter specific competition. the lowest grain yield (7.27 t ha-1 in 2014-15 and 7.5 t ha-1 in 2015-16) was obtained from maize normal planting (100%) + 1 row squash (plant to plant 80 cm) (116%) due to increased plant population of squash that resulted lower single cob weight and 1000 grain weight. table 1. grain yield and yield components of maize in maize squash intercropping system during 2014-15 and 2015-16 treatments single cob wt (gm) 1000grain wt (gm) grain yield (t ha-1) 201415 201516 201415 201516 201415 201516 maize normal planting (75 cm x 25 cm) 251.27 258.2 329.55 352.2 9.47 9.24 maize normal planting (100%) + 1 row squash (pl. to pl. 80 cm (116%) 181.27 208.7 263.56 310.53 7.27 7.5 maize paired row (100%) + 1 row squash (pl. to pl. 80 cm) (50%) 226.8 248.3 300.67 342.6 8.82 8.02 maize paired row (100%) + 1 row squash (pl. to pl. 1 m) (40%) 236.67 252.88 305.46 342.8 9.01 8.3 maize paired row (100%) + 2 rows squash (pl. to pl. 80 cm) (100%) 186.4 213.65 284.1 312.4 8.00 7.67 maize paired row (100%) + 2 rows squash (80%) 206.2 235.75 303.37 332.6 8.38 8.2 sole squash (1 m x 80 cm) lsd(0.05) 59.13 24.47 44.6 25.32 2.14 0.89 cv (%) 16.09 5.69 8.12 4.2 13.89 5.96 performance of squash: fruit number plant-1, fruit weight plant-1, and fruit yield of squash were significantly influenced under different intercropping system in both the years (table 2). the highest fruit plant-1 (3.66 in 2014-15 and 3.16 in 2015-16) and weight of fruit plant-1 (3.92 kg in 2014-15 and 3.43 kg in 2015-16) were recorded from sole squash. in case of intercropping system, the highest number 22 chowdhury et al. of fruit plant-1 (2.88 in 2014-15 and 2.63 in 2015-16) and weight of fruit plant1 (3.21 kg in 2014-15 and 2.96 kg in 2015-16) were obtained when 40% squash was sown and the lowest values when 116% squash with maize. it might be due to competition for resources. single fruit weight was significantly affected by intercropping system in 2015-16 but not in 2014-15. the highest single fruit weight was found in sole plot. among intercropping system the highest fruit weight was obtained from mpr+ 1 row squash (40%) combination. sole squash showed highest fruit weight /plant. the highest fruit yield (28.19 t ha-1 in 201415 and 25.02 t ha-1 in 2015-16) was found in sole squash. there was trend to decrease fruit yield in both normal and paired row situation as intercrop. the lowest yield (11.73 t ha-1 in 2014-15 and 8.26 t ha-1 in 2015-16) was obtained when 40% squash was sown with maize. significant yield differences in different intercropping systems mainly attributed to the differences in plant population. increasing the density of squash plants significantly increased the yield of intercropped squash compared to that obtained from intercropped with low density of squash populations. in intercropping situation the highest squash yield (19.39 t ha-1 in 2014-15 and 14.76 t ha-1 in 2015-16) was obtained in maize paired row (100%) + 2 rows squash (plant to plant 80 cm) (100%) treatment. table 2. fruit yield and yield components of squash in maize squash intercropping system during 2014-15 and 201516 treatments fruit plant-1 (no.) single fruit wt. (kg) fruit wt. plant-1 (kg) fruit yield (t ha-1) 201415 201516 201415 201516 201415 201516 201415 201516 maize normal planting (75 cm x 25 cm) maize normal planting (100%) + 1 row squash (pl. to pl. 80 cm) (116%) 2.22 2.13 1.12 1.17 2.17 1.91 15.17 10.35 maize paired row (100%) + 1 row squash (pl. to pl. 80 cm) (50%) 2.44 2.4 1.16 1.34 2.67 2.73 13.46 9.68 maize paired row (100%) + 1 row squash (pl. to pl. 1 m) (40%) 2.88 2.63 1.2 1.44 3.21 2.96 11.73 8.26 maize paired row (100%) + 2 rows squash (pl. to pl. 80 cm) (100%) 2.3 2.3 1.1 1.24 2.24 2.13 19.39 14.76 maize paired row (100%) + 2 rows squash (80%) 2.33 2.36 1.14 1.26 2.3 2.53 17.61 10.95 sole squash (1 m x 80 cm) 3.66 3.16 1.26 1.70 3.92 3.43 28.19 25.02 lsd(0.05) 0.49 0.37 ns 0.16 0.68 0.68 5.09 2.00 cv (%) 10.30 9.09 5.87 6.24 13.58 0.315 16.21 8.61 ns = not significant; pl = plant intercrop efficiency maize equivalent yield (mey), land equivalent ratio (ler) and benefit cost analysis of maize squash intercropping are presented in table 3. maize equivalent yield was influenced by different intercropping systems. it was noted that all the intercropping systems gave higher maize equivalent yields than that of sole maize yield. maize equivalent yields (4.97-19.39 t ha-1) in all intercropping systems were higher than sole maize (9.35 t ha-1) indicating higher productivity of intercropping systems. similar results were mentioned by alom et al. (2013). among intercropping squash with maize under varying planting system 23 intercropping systems, maximum mey (19.39 t ha-1) was recorded in maize paired row (100%) + 2 rows squash (100%) combination. higher mey in this combination might be contributed by combined effect of both the components. ler (1.47) also higher in maize paired row (100%) + 2 rows squash (plant to plant 80 cm) (100%) treatment combination indicating 47% higher land use efficiency. the higher ler might be due to better utilization of growth resources. the results are in agreement with the findings of seran and brintha (2009). the highest gross return tk. 2,93,850 ha-1, gross margin tk. 1,92,450 ha-1 and bcr 2.95 were obtained from maize paired row (100%) + 2 rows squash (100%). this result is in agreement with the finding of islam et al. (2013). gross margin was higher under intercropping systems than that of sole cropping systems. many investigators also reported higher gross margin in intercropping system than sole crop (razzaque et al., 2007 and alom et al., 2008). the cost of cultivation was much higher under all intercropping systems than sole maize this was mainly due to more expenditure in extra labour required for sowing, harvesting, and intercultural operation of two crops. monetary advantages were also obtained by bandyopadhyay (1984) from intercrop combinations of different crops. table 3. maize equivalent yield (mey), land equivalent ratio (ler) and economic analysis of maize-squash inter cropping systems (average of two years) treatments maize equivalen t yield (t ha-1) ler gross return (tk ha-1) cost of production (tk ha-1) gross margin (tk ha-1) bcr maize normal planting (75 cm x 25 cm) 9.35 1.00 140325 69000 71325 2.03 maize normal planting (100%) + 1row squash (pl. to pl. 80 cm) (116%) 15.89 1.26 238350 99500 140350 2.39 maize paired row (100%) + 1 row squash (pl. to pl. 80 cm) (50%) 16.13 1.33 241950 82500 159450 2.93 maize paired row (100%) + 1 row squash (pl. to pl. 1 m) (40%) 14.97 1.29 229800 79600 150200 2.89 maize paired row (100%) + 2 rows squash (pl. to pl. 80 cm) (100%) 19.39 1.47 290850 98400 192450 2.95 maize paired row (100%) + 2 rows squash (80%) 17.80 1.42 267000 94700 172300 2.81 sole squash (1 m x 80 cm) 17.73 1.00 266025 92000 174025 2.88 market price: (tk kg-1): maize= 15, squash= 10 conclusion two years results revealed that squash grown as intercrop with maize is more profitable one than sole maize. so, maize paired row 37.5 cm/ 150 cm/ 37.5 cm (100%) + 2 rows squash (plant to plant 80 cm) (100%) combination could be suitable for higher productivity and economic return. references about:blank#572504_ja 22 chowdhury et al. ahmed, f., m. n. islam, m. s. alom, m. a. i. sarker and m. a. mannaf. 2013. study on intercropping leafy vegetables with okra (abelmoschus esculentus l.). bangladesh j. agril. res. 38(1): 137-143. alom, m. s., n. k. paul, and m. a. quayyum. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean (vigna radiata l.) in different planting methods. saarc j. of agri. 6(2): 73–82. bandyopadhyay, s. n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. islam, m. n., m. m. haque and a. hamid. 2004. spatial arrangement and population density effects on productivity of maize–bushbean intercropping systems. bangladesh j. agril. res. 29(3): 467-474. islam, m. n., m. s. rahman, f. ahmed, m. s. alom and m. akhteruzzaman. 2013. performance of different hyv mustard varieties with sugarcane (sacchaarum officinarum) as intercrop in farmers’ fields. bangladesh j. agril. res. 38(1): 137-143. lewis, w., jett, j. s. chism, s. p. conley. 2003. intercropping systems for tomato within a high tunne, report submitted to dept.of horticulture, missouri univ.colombia: 1-18. mahfuza, s. n., m. n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping of different vegetables and spices with pointed gourd. j. exp. biosci. 3(1): 77-82. razzaque, m. a., s. rafiquzzaman, m. m. bazzaz, m. a. ali, and m. m. r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agril. res. 32(1): 37-43. seran, t. h. and i. brintha, 2009. studies on determining a suitable pattern of capsicum (capsicum annum l.) vegetable cowpea (vigna unguiculata l.) intercropping. karnataka j. agric. sci. 22: 1153-1154. shivay, y. s., r. p. singh and c. s. pandey. 1999. response of nitrogen in maize (zea mays)based intercropping system. indian j. agron. 44: 261-266. uddin m. j., m. a. quayyum and k. m. salahuddin. 2009. intercropping of hybrid maize with short duration vegetables at hill valleys of bandarban. bangladesh j. agril. res. 34(1): 51-57. willey, r. w. 1985. evaluation and presentation of intercropping advantages. exp. agric. 21(2): 119-133. bangladesh agron. j. 2018, 21(2): 59-65 on-farm evaluation of orange fleshed sweet potato varieties under acidic soil of north-east region in bangladesh m. i. nazrul senior scientific officer, on-farm research division, bangladesh agricultural research institute (bari) *corresponding author, e-mail: mi_nazrul@yahoo.com; m.i.nazrul@gmail.com (received: 3 december 2018, accepted: 26 february 2019) keywords: sweet potato, acid soil, genotypes, orange flesh, morpho-physiology abstract an on-farm trial with four orange fleshed sweet potato varieties viz. bari mishti alu-4, bari mishti alu-8, bari mishti alu-12, bari mishti alu-13 including local check (muli alu) were evaluated at farming system research and development (fsrd) site, jalalpur, sylhet, bangladesh during rabi season for two consecutive years (2016-2017 & 2017-2018) under surma‐kushiyara floodplain of bangladesh. the experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. the results revealed that the genotypes varied considerably in tuber root yields and yield attributing characters. considering the average tuber root yield performance orange fleshed sweet potato varieties performed better than local variety (muli alu). however, among the varieties under studied bari mishti alu-12 produced higher roots yield (40.63 t ha-1) than the other tested varieties. considering economic return, the highest gross margin (tk. 5,65,110 ha-1) and benefit cost ratio (5.50:1.00) was also obtained from sweet potato var. bari mishti alu-12 and the lowest returnfrom var. bari mishti alu-4 with benefit cost ratio of 3.54. though the local cultivar (muli alu) produced lower root yields but it provided considerable gross margin (tk.3,76,240 )and bcr (3.99:1.00 ) which closed to bari mishti alu-12. it is due to higher demand of local cultivar with high price in the local market. therefore, the genotypes bari mishti alu-12 and local cultivar (muli alu) were found suitable for their better growth and yield under the acidic soils. introduction sweet potato (ipomoea batatas l.) is one of the most important tuber crops in bangladesh which can be used as substitute of cereal crops to meet the up food shortage.. the foliage has the potential for use as vegetable and animal feed (otoo et al., 2001). it is the fourth important crop in bangladesh after rice, wheat and potato (delowar and hakim, 2014). orange-fleshed sweet potato (ofsp) varieties are rich in beta-carotene, while purple-fleshed ones are high in anthocyanin. these two important antioxidants thought to prevent chronic heart diseases and cancer (teow et al., 2007). the orange flesh sweet potato has significant antioxidant activity, and can potentially improve vitamin-a status in children (laurie et al, 2015; hotz et al., 2012; li and mu, 2012; burri, 2011). emerging health benefits of the orange flesh sweet potato (ofsp) are substantial, making it an even more important food-especially for populations in danger of malnutrition (aywa et al. 2013; kaspar et al., 2013). the average yield and area coverage of sweet potato is quite low compared to world context. sweet potato is a promising crop for some areas of sylhet region. it is mainly about:blank 64 m. i. nazrul cultivated by the marginal or subsistence farmers in a sporadic way in different river belts, char lands, deltas and seasonally inundated flood plains (ahmed et al., 1998). farmers cultivate sweet potato with traditional varieties after t. aman rice or in land remain fallow with no or less care and input. for this reason sweet potato could not express its yield potentiality and resulting produced low root yield. bangladesh agricultural research institute (bari) has developed some new varieties of sweet potato that have high yielding ability and also contain rich in carotene. among the sweet potato varieties bari mishti alu-4, bari mishti alu8, bari mishti alu-12 and bari mishti alu-13 are high yield potentially and also contain higher amount of carotene. for increasing sweet potato yield and higher economic return along with the supplement of carotene to the consumer, farmer’s need to cultivate high yielding carotene rich sweet potato varieties. keeping these views in mind, the experiment was conducted to evaluate the performance of orange flesh sweet potato varieties in acidic soil of sylhet. materials and methods descriptions of the experimental locations an on-farm study was conducted at farming system research and development (fsrd) site, jalalpur in sylhet district during rabi season for two consecutive years (2016-2017 & 2017-2018) under surma‐kushiyara floodplain soil of bangladesh. the study area located between 24°43' & 24°54' n latitude and 91°47' & 91°98' e longitude and on an altitude of 10 meters. soil and climate the experimentation on orange flesh sweet potato varieties conducted at farmer’s field to evaluate the performance of color flesh sweet potato varieties in acidic soil of sylhet. the climate and soil of the selected plot was under subtropical climate having heavy rainfall during monsoon and scanty or very little shower during prolong dry winter season, high to medium high land, and well drained grey floodplain fertile soils of acidic in nature. type of experimental soil is noncalcareous gray with low organic matter content (1.29%), low soil ph (4.5-5.2), very low total n (0.06%), low content of p (8.59), k (0.13) and s (9.14) where as zn (1.22) and boron (0.48) medium and optimum, respectively. fig. 1. minimum, maximum and average temperature (°c) pattern in experimental location of sylhet 0 5 10 15 20 25 30 35 40 jan 2016 feb mar oct nov dec jan 2017 feb mar oct nov dec minimum average maximum t em p er at ur e (0 c ) on-farm evaluation of orange fleshed sweet potato varieties 65 fig. 2. rainfall (mm) pattern in experimental location under sylhet during experimentation. the monthly temperature and rainfall of the experimental site are indicated in figure 1 and 2. the climatic data during experimentation shows that the average minimum and maximum temperature was 16.2 °c and 27.15 °c, respectively. on the contrary, the annual minimum and maximum temperature was 7.5 °c and 33.6 °c in the month of january and march, respectively. as indicated in meteorological station, sylhet rainfall of the area is uni-modal, usually occurring during april to october, and total annual rainfall reached to 4217 mm; whereas in december-january no rain at all and lowest amount of rainfall occurs in february followed by march (figure 2). however, generally rainfall increases gradually from the month of may and continued up to september. experimental materials and design five different varieties of orange flesh sweet potato including local one viz. bari mishti alu-4, bari mishti alu-8, bari mishti alu-12, bari mishti alu-13 and local check (var. muli alu) were used as experimental materials. physiomorphological characteristics of sweet potato root tubers of experimented varieties are presented in table 1. the experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. the size of each unit plot was 2 m  5 m. the vines of sweet potato were planted on 20-25 october, 2016-17 and 2017-18 with maintaining the spacing at 60 cm  30 cm. table 1. tuberous root characteristics of bari released sweet potato and check (muli alu) varieties variety root shape and size skin color flesh color b-carotene (mg/ 100g fresh wt.) dry matter (%) bari mishti alu-4 round elliptic orange brown orange 4.41 26.00 bari mishti alu-8 round elliptic purple red intermediate yellow 1.17 29.52 bari mishti alu12 long elliptic intermediate pink orange 4.41 34.85 bari mishti alu13 long elliptic cream pale yellow orange 1.76 26.93 local (muli alu) long elliptic light cream white 0.03 30.47 source: (burgos, et al., 2009). 0 20 40 60 80 100 120 140 160 jan 2016 feb mar oct nov dec jan 2017 feb mar oct nov dec r ai n fa ll ( m m ) 64 m. i. nazrul the average size of vine cuttings ranges from 20-30 cm long with six to seven nodes. the field was fertilized with 70-25-88 kg ha-1 of npk and 5-6 t ha-1 organic matter, respectively. half of urea and all others fertilizer were used at final land preparation. remaining part of n fertilizer was applied at the side of the row in two equal splits at 30 & 60 days after transplanting followed by irrigation. one weeding and ear thing up was done 30 days after transplant. there was no remarkable disease and pest attack. data collection and analysis the tuberous root was harvested variety wise on 25-28 march, 2016-17 1nd 2017-18 when drying of latex to white color in cut surface of roots and old leaves become yellowing to some extent. the data collection on morphological attributes was started at 60 days after planting and continued with an interval of 30 days until final harvest. at harvest, data of yield and yield components like length of vine, tuberous roots plant-1, weight of single root, root yield plot-1 and root yield ha-1 were recorded from 10 randomly selected plants in each plot and yield of tuberous roots was recorded plot wise. the collected data were analyzed statistically using “star” software package and means were separated by lsd. results and discussion length of vine the main vine length of tested orange flesh sweet potato varieties measured at 120 days after transplanting of cutting showed significant variation (table 2). the highest vine length was observed in local cultivar muli alu (192.33 cm). rahaman et al. (2015) was also found that the vine length at 120 days after planting was ranged from 165.33 to 230.27 cm which is consistent to the present study. on the contrary, bari mishti alu-13 produced the shortest vine (119.00 cm) at 120 days after planting. vine length differs due to the genetic makeup present in the genotypes as well as tolerance to the acidic soil environment. results are in agreement with the findings of kareem (2013), reported that medium sized vine length ranges from 140-180 cm gave the best yield of sweet potato. similar results were found in literature stated that the vine length differ from 220.17-264.43 cm due to their genetic make-up of sweet potato. number of tuberous roots plant-1 the yield and yield contributing characters of the studied varieties were varied significantly. results of two consecutive years of trial revealed that the sweet potato var. bari mishti alu-12 produced the maximum number of tuberous roots (9.67) plant-1. these results are closely related with those reported by rahman et al. (2015) where the number of tuberous root per plant was about 7.13 in bari mishti alu-7. weight of single root (g) overall, single weight of tuberous root in var. bari mishti alu-12 was recorded significantly higher compared to other varieties in this trial. the sweet potato var. bari mishti alu-12 produced biggest size of (166.67 g) tuberous root that was very close to the root weight (163.33 g) of local cultivar named muli alu. the bigger size of tuberous roots may be contributed higher root yields. whereas, the var. bari mishti alu-4 produced the smallest root size. root yield plot-1 the tuberous root yields varied significantly with varieties used in this on-farm trial. the highest tuberous root weight plot-1 (8.13 kg) was observed in var. bari mishti alu-12; whereas the lowest yield (5.45 kg) was obtained from local on-farm evaluation of orange fleshed sweet potato varieties 65 cultivar muli alu. on the other hand, statistically similar tuberous root yield per plot was produced by var. bari mishti alu-8 and bari mishti alu-13. sen et al. (1988) stated that significant variations among the genotypes were happened might be due to the adoption of proper cultural management techniques. root yield (t ha-1) the yield of tuberous roots varied markedly among five tested sweet potato varieties. the sweet potato var. bari mishti alu-12 produced the maximum yield of tuberous root (40.63 t ha-1) closely followed by bari mishti alu-8 (30.40), bari mishti alu-13 (29.70 t ha-1) and bari mishti alu-4 (29.64 t ha-1) whereas the lowest yield of tuberous roots (27.88 t ha-1) was obtained from the local cultivar muli alu. several researchers found that yield potentiality of sweet potato depends on the genetic make-up of plants (naskar and chowdhury, 1994; siddique et al., 1988; yooyongwech et al., 2014). farmer’s feedback farmers’ expressed that once the sweet potato was indigenized root crop cultivated by poor farmers with poor management and they used to believe it contributes very low nutritional supplement. at present they are very much conscious about vitamins, minerals, dietary fibre and protein which are containing sweet potato. as a result they changed attitude and shown keen interest to cultivate orange or yellow flesh sweet potato especially bari mishti alu-12 due to its carotene rich and creating market demand in sylhet. table 2. tuberous root yield and yield contributing characters of sweet potato at fsrd site, jalalpur, sylhet varieties length of vines (cm) tuberous roots plant-1 wt. of single tuberous root (g) tuberous root yield plot-1 (kg) tuberous root yield (t ha-1) bari mishti alu-4 164.33 5.00 97.67 5.93 29.64 bari mishti alu-8 149.67 5.33 111.00 6.08 30.40 bari mishti alu-12 119.67 9.67 166.67 8.13 40.63 bari mishti alu-13 119.00 7.33 148.33 5.94 29.70 local (muli alu) 192.33 4.33 163.33 5.45 27.88 cv (%) 12.46 13.32 12.16 10.82 10.54 lsd (0.05) 31.39 4.32 29.31 2.33 2.30 economic analysis regarding economic return, the highest gross margin and benefit cost ratio was obtained from sweet potato var. bari mishti alu-12 and the lowest return was achieved from var. bari mishti alu-4 with benefit cost ratio of 3.54. table 3. cost and return analysis of sweet potato varieties at fsrd site, south surma, sylhet varieties price of root tubers (tk kg-1) gross return (tk ha-1) total variable cost (tk ha-1) gross margin (tk ha-1) benefit cost ratio (bcr) bari mishti alu-4 15.00 444600 125600 319000 3.54 bari mishti alu-8 15.00 456000 125600 330400 3.63 bari mishti alu12 17.00 690710 125600 565110 5.50 bari mishti alu13 15.00 445500 125600 319900 3.55 local (muli alu) 18.00 501840 125600 376240 3.99 64 m. i. nazrul though the local cultivar (muli alu) produced lower tuberous root yields but it provided considerable gross margin and bcr which closed to bari mishti alu12. it is due to higher price of tuberous root in the local market. conclusions of the orange flesh sweet potato varieties and cultivar evaluated in sylhet region, the high yielder sweet potato var. bari mishti alu-12 had acceptable tuberous root yields with maximum economic profit. though the local cultivar (muli alu) of sweet potato was low yielder but already created local market demands for its sweetness. acknowledgement the authors extend their gratitude to the tuber crop research center of bangladesh agricultural research institute (bari), for providing the vines of orange flesh sweet potato varieties. the two organizations metrological department and soil resource development institute of sylhet district are thanked for the cooperation accorded. references ahmed, m. d. s., m. a. quadir, m. k. r. bhuiyan and t. r. dayal. 1998. genetic diversity of sweet potato (ipomoea batatas l.). bangladesh j. root crops. 24: 11-15. away, a. k., m. p. nawiri, h. n. nyambaka. 2013. nutrient variation in colored varieties of ipomea batatas grown in vihiga county, western kenya. int. food res. j. 20(2): 819-825. burgos, g., r. caprio, c. sanchez, p. sosa, e. porras, j. espinoza and w. gruneberg. 2009. guide for using the rhs color chart for selecting for high β-carotene sweet potato. poster at istrc, lima, peru. burri, b. j. 2011. evaluating sweet potato as an intervention food to prevent vitamin-a deficiency. comp. rev. food sci. food safe. 10:118-130. delowar, h. k. m and m. a. hakim. 2014. effect of salinity levels on the morphophysiological characteristics and yield attributes of sweet potato genotypes. int. j. sci. res., 10: 929-934 kareem, i. 2013. growth, yield and phosphorus uptake of sweet potato (ipomoea batatas) under the influence phosphorus fertilizers. res. j. chem. environ. sci., 1: 50-55. kaspar, k. l., j. s. park, c. r. brown, k. weller, c. f. ross, b. d. mathison and b. p. chew. 2013. sensory evaluation of pigmented flesh potatoes (solanum tuberosum l.). food nutr. sci. 4:77-81. laurie, s. m. and s. m. van heerden. 2012. consumer acceptability of four products made from beta-carotene-rich sweet potato. afr. j. food sci. 6:96103. li, p. g. and t. h. mu. 2012. sweet potato: health benefits, production and utilization in china. in potatoes: production, consumption and health benefits. c. caprara (edn.). nova science publishers. pp. 127-172. naskar, s. k. and s. r. chowdhury, 1994. growth and yield response of eight sweet potato lines. indian j. plant physiol., 37: 200-202. on-farm evaluation of orange fleshed sweet potato varieties 65 otoo, j. a., a. missah and a. g. carson. 2001. evaluation of sweet potato for early maturity across different agro-ecological zones in ghana. afr. crop sci. j., 9: 25-32. rahaman, e. h. m. s., a. a. mahmud, m. hossain, h. c. mohanta, m. a. rahman, m. s. i. haque, m. e. khan, m. m. hossain, m. m. hasan and b. merideth. 2015. field performance of sweet potato varieties in saline zone of bangladesh. bangladesh hort. 1(1 & 2): 67-76. rahman, h., a. f. m. s. islam, m. m. abdul and r. tabassum. 2015. morphophysiological evaluation of sweet potato (ipomoea batatas l.) genotypes in acidic soil. asian j. crop sci. 7 (4): 267-276. siddique, m. a., a. t. m. hassanuzzaman and h. akbar. 1988. growth and yield of three high-yielding sweet potato genotypes. bangladesh j. agric. 13: 139146. teow, c. c., v. d. truong, r. f. mc feeters, r. l. thompson, k.v. pecota and g. c. yencho. 2007. antioxidant activities, phenolic and b-carotene contents of sweet potato genotypes with varying flesh colors. food chem. 103: 829– 838. yooyongwech, s., t. samphumphuang, c. theerawitaya and s. cha-um, 2014. physio-morphological responses of sweet potato (ipomoea batatas l.) genotypes to water-deficit stress. plant omics j. 7: 361-368. bangladesh agron. j. 2019, 22(2): 77-82 effect of field duration on yield and yield attributes of tossa jute varieties at different agroecological zones j. ferdous, m.s. hossain, m.a. alim and m.m. islam1 agronomy division and 1planning, training and communication division, bangladesh jute research institute, dhaka, bangladesh corresponding e-mail: tanny.jannat92@gmail.com (received: 01 january 2020, accepted: 18 february 2020) keywords: jute, field duration, yield and location abstract the experiment was conducted at jute agriculture experimental station (jaes), manikganj; jute research regional station (jrrs), rangpur and jute research sub station (jrss), jessore in 2017 to determine optimum field duration on yield and yield attributes of different tossa jute varieties. the experiment was laid-out in rcbd with three replications. tossa jute varieties o-9897, bjri tossa pat-5 and jro-524 were used as planting materials. crops were sown on last week of march to first week of april. the crops were harvested at different field durations (90 days, 100 days and 110 days after sowing) regarded as treatment. all crops were attained recommended cultural practices. result showed that bjri tossa pat-5 gave higher fibre production in 90 days at manikganj and rangpur (2.69 tha-1and 2.34tha-1 respectively)and 100 days field duration which was followed by jro -524 (2.36 tha-1 and 2.24 tha-1 respectively)and o9897(2.21 tha-1and 4.54 tha-1, respectively), however at 110 days jro-524 (3.40 tha-1; 3.34 tha-1and 3.16 tha-1 respectively) gave the higher fibre yield compare other two varieties bjri tossa pat-5 (3.20 tha-1; 3.14 tha-1and 3.12 tha-1 respectively) and o9897 (3.05 tha-1; 2.99 tha-1and 2.99 tha-1 respectively) at manikganj , rangpur and jessore. introduction jute is a cash crop of bangladesh. jute (corchorus spp.) is a common term used both for plant and the fibre obtained from the bark of the plants, corchorus capsularis l. and c. olitorius l. there are over 30 species, which belongs to the genus corchorus. it is grown in the summer season (kharif-i) (islam and rahman, 2008). jute being the most important cash crop plays a major role in agriculture and our national economy. it also holds an important position in the industrial sector of bangladesh. bangladesh produces world’s best quality jute. the agricultural climate of bangladesh is very much suitable for quality fibre production (islam and uddin, 2019). the productivity of jute had doubled from 1.50 t/ha during 1970-80 to about 2.04 t/ha during 2015-16. development of high-yielding varieties were the one of the main specific technologies which made this possible. in 1970-80 decades about 15-16 lakh hectare of the total cultivable land was occupied by jute has now (2014-15) been reduced to about 7.00 to 8.00 lakh hectare which produced bout 16-17 lakh tons of fibre. however, national average yield is increased from 1.59 to 2.04 tons per hectare (bbs, 2015). it is happened due to use of high yielding jute varieties and production technologies, which together contributed toward higher yield. in bangladesh, annually about 0.817 millions ha of land is cultivated for the production of about 0.162 million tons of fibre. to cultivate the said area, the farmers require about 5000 to 5500 tons of jute seed (islam and uddin, 2019). many jute farmers use to produce jute crops by their own seeds to meet their requirements but such seeds are of poor in quality. one of the most important 78 ferdous et al. problems for jute production in bangladesh is the unavailability of quality seed at proper time of sowing. only about 10% to 15% quality jute seeds are supplied by different national agencies but the rest amount of quality seed is yet to be managed to supply (islam and rahman, 2008). the government of bangladesh has given more thrust to promote the jute seed industry by strengthening public sectors dealing with jute seed and also by sensitizing private sectors to reduce the dependence on imported jute seed. the activities of private sectors regarding jute seed are limited on seed import only (islam and ali, 2017). but the present status of jute as a cash crop facing a problem for increasing preference to food crop due to population pressure. so, to sustain jute in cropping pattern, short duration is needed. generally, jute takes 120 days field duration. objectives of the present study is related to the field duration by keeping the optimum yield and quality of jute fibre. in this context two prominent tossa jute varieties o-9897 and o-795 were tested with jro-524 for optimum field duration to assess the yield and quality of fiber. materials and methods the experiment was conducted at jute agriculture experimental station (jaes), manikganj, jute research regional station, rangpur and jute research sub station, jessore during the year 2017. the experiments were laid out in rcbd with three replications. unit plot size was 4.0m x 2.5m. space between plot to plot and around the field was 1.0 m and between replications 1.5 m. two prominent tossa jute varieties o-9897 and bjri tossa pat-5 (o-795) and jro-524 were used as planting materials. crops were sown on last week of march to first week of april. the crops were harvested at different field duration, (90 days, 100 days and 110 days after sowing) regarded as the treatment. other cultural and intercultural practices were attended as per bjri recommendation. location wise average data of fibre yield and quality attributing characters were analyzed with the help of computer statistical package (mstat-c). the mean differences among the treatments were adjusted by least significant difference (lsd) at 0.05 level (gomez and gomez, 1984). results and discussion results revealed that yield and yield contributing characters like plant population, base diameter and plant height, fibre yield and stick yield were affected significantly at manikganj. fibre yield and stick yield were differed significantly due to variety irrespective of sowing date at manikganj but at rangpur and jessore all the yield contributing data like plant population, base diameter and plant height, fibre yield and stick yield were not differed significantly (table 1). bjri tossa pat-5 gave numerically higher fibre yield (2.90 tha-1 and 2.75 tha-1, respectively) which was followed by jro -524 (2.70 tha-1 and 2.74 tha-1, respectively) and varieties o-9897 (2.69 tha-1and 2.53 tha-1, respectively) at manikganj and rangpur. jro-524 gave numerically higher fibre yield (3.22 tha-1) which was followed by tossa jute varieties bjri tossa pat-5 (2.67 tha-1) and o-9897 (2.54 tha-1) at jessore. it was observed that fibre yield and stick yield were differed significantly due to variety irrespective of sowing date at manikganj but at rangpur and jessore all the yield contributing data were not differed significantly (table 2). crop harvested on 110 days gave the highest fibre and stick yields (3.22 tha-1 and 6.56 tha-1, respectively). plant height (3.05 m) and base diameter (17.05 mm) were also found the highest at the same date. the crop harvested on 90 days recorded the lowest fibre and stick yields (2.42 tha-1 and 4.92 tha-1, respectively) at manikganj. at rangpur, yields and all the yield contributing parameters like plant population, base diameter and plant height, fibre yield and stick yield were not differed significantly due to longer field duration irrespective of variety (table 2). crop harvested on 110 days gave the highest fibre and stick yields (3.16 tha-1 and 6.17 tha-1, respectively). effect of field duration on yield and yield attributes of tossa jute 79 table 1. effect of variety irrespective of field duration on fibre yield and yield components of tossa jute at different locations location treatment plant population (m-2) plant height (m) base diameter (mm) fibre yield (tha-1) stick yield (tha-1) manikganj o-9897 32.98 2.60 14.44 2.59 5.55 bjri tossa pat-5 33.95 2.83 15.38 2.90 5.99 jro-524 33.82 2.70 14.99 2.70 5.62 lsd(0.05) 0.367 0.055 0.084 0.062 0.077 % cv 1.09 2.06 0.55 2.23 0.67 rangpur o-9897 34.93 2.84 14.20 2.53 5.26 bjri tossa pat-5 34.62 2.89 15.22 2.75 5.76 jro-524 34.39 2.88 14.91 2.74 5.51 lsd(0.05) ns ns ns ns ns % cv 1.02 0.85 0.35 2.23 0.71 jessore o-9897 33.84 2.72 14.12 2.54 5.31 bjri tossa pat-5 33.31 2.76 14.89 2.67 5.53 jro-524 32.89 2.88 15.40 2.74 5.83 lsd(0.05) ns ns ns ns ns % cv 0.54 0.94 2.55 1.47 0.73 legend: ns = not-significant table 2. effect of field duration irrespective of variety on fibre yield and yield components of tossa jute at different locations location treatment plant population (m-2) plant height (m) base diameter (mm) fibre yield (tha-1) stick yield (tha-1) manikganj 90 days 34.47 2.47 13.22 2.42 4.92 100 days 33.71 2.60 14.55 2.56 5.68 110 days 32.56 3.05 17.05 3.22 6.56 lsd(0.05) 0.367 0.055 0.084 0.062 0.077 % cv 1.09 2.06 0.55 2.23 0.67 rangpur 90 days 35.72 2.61 13.06 2.24 4.75 100 days 34.68 2.86 14.39 2.61 5.60 110 days 33.54 3.13 16.89 3.16 6.17 lsd(0.05) ns ns ns ns ns % cv 1.02 0.85 0.35 2.23 0.71 jessore 90 days 34.42 2.53 13.13 2.24 4.81 100 days 33.40 2.78 14.44 2.62 5.66 110 days 32.22 3.05 16.83 3.09 6.20 lsd(0.05) ns ns ns ns ns % cv 0.54 0.94 2.55 1.47 0.73 legend: ns = not-significant 80 ferdous et al. plant height (3.13 m) and base diameter (16.89 mm) were also highest at the same date. the crops that harvested on 90 days recorded the lowest fibre and stick yield production (2.24 tha-1 and 4.75 tha-1, respectively). at the same time similar result found at jessore (table 2). crop harvested on 110 days gave the highest fibre and stick yields (3.09 tha-1 and 6.20 tha-1, respectively). plant height (3.05 m) and base diameter (16.83 mm) were also found the highest at the same date. the crop harvested on 90 days recorded the lowest fibre and stick yields (2.42 tha-1 and 4.81 tha-1, respectively) at jessore. weng et al. (1990) reported similar findings in kenaf and jute. in case of interaction effect of variety and field duration was observed that at manikganj plant population, base diameter and plant height, fibre yield and stick yield were not differed significantly due to interaction effect of variety and field duration. highest fibre yield and stick yield was recorded at bjri tossa pat-5 (2.69 tha-1 and 5.36 tha-1, respectively) which was followed by jro -524 (2.36 tha1 and 4.85 tha-1, respectively) and varieties o-9897 (2.21 tha-1and 4.54 tha-1, respectively) at 90 days (figure 1). at 100 days, bjri tossa pat-5 also gave higher fibre yield (2.82 tha-1) which was followed by varieties o-9897 (2.51 tha-1) and jro -524 (2.35 tha-1) but at 110 days jro -524 gave the higher fibre yield (3.40 tha-1) which was followed by varieties bjri tossa pat-5 (3.20 tha-1) and o-9897 (3.05 tha-1). the results were in agreement with islam et al. (1995) and hsu and chi (1976). legend: v1= o-9897, v2= o-795, v3= jro-524; d1=90 days, d2= 100 days, d3= 110 days. fig. 1. interaction effect of variety and field duration on fibre yield and yield components of tossa jute at manikganj. in case of rangpur, it was observed that plant population, base diameter and plant height, fibre yield and stick yield fibre yields and stick yield were differed significantly due to interaction effect of variety and field duration. the highest fibre yield and stick yield was obtained from bjri tossa pat-5 (2.34 tha-1 and 5.11 tha-1, respectively) which was followed by jro -524 (2.24 tha-1 and 4.73 tha-1, respectively) and varieties o-9897 (2.15 tha-1 and 4.42 tha-1, respectively) at 90 days (figure 2). bjri tossa pat-5 also gave higher fibre yield (2.76 tha-1) which was followed by jro -524 (2.63 tha-1) and varieties o-9897 (2.45 tha-1) at 100 days but jro -524 gave the higher fibre yield (3.34 tha-1) which was followed by varieties bjri tossa pat-5 (3.14 tha-1) and o-9897 (2.99 tha-1) at 110 days. effect of field duration on yield and yield attributes of tossa jute 81 legend: v1= o-9897, v2= o-795, v3= jro-524; d1=90 days, d2= 100 days, d3= 110 days. fig. 2. interaction effect of variety and field duration on fibre yield and yield components of tossa jute at rangpur. legend: v1= o-9897, v2= bjri tossa pat-5, v3= jro-524; d1=90 days, d2= 100 days, d3= 110 days. fig. 3. interaction effect of variety and field duration on fibre yield and yield components of tossa jute at jessore. at jessore, plant population, base diameter and plant height, fibre yield and stick yield fibre yields and stick yield were differed significantly due to interaction effect of variety and field duration. result showed that the highest fibre yield and stick yield was obtained from jro -524 (2.29 tha-1 and 5.17 tha1, respectively) which were followed by tossa variety bjri tossa pat-5 (2.28 tha-1 and 4.79 tha-1, respectively) and varieties o-9897 (2.15 tha-1and 4.48 tha-1, respectively) at 90 days (figure 3). at 100 days, jro -524 also gave higher fibre yield (2.76 tha-1) which was followed by tossa variety bjri tossa pat-5 (2.63 tha-1) and varieties o-9897 (2.46 tha-1) and at 110 days jro-524 gave the higher fibre yield (3.16 tha-1) which was followed by varieties bjri tossa pat-5 (3.12 tha-1) and o-9897 (2.99 tha-1). similar results were found by islam et al. (1995) and hsu and chi (1976). 82 ferdous et al. conclusion bjri tossa pat-5 gave higher fibre production in 90 days at manikganj and rangpur (2.69 tha-1and 2.34tha-1 respectively)and 100 days field duration which was followed by jro -524 (2.36 tha-1 and 2.24 tha-1 respectively)and o-9897(2.21 tha-1and 4.54 tha-1, respectively), however at 110 days jro-524 (3.40 tha-1; 3.34 tha-1and 3.16 tha-1 respectively) gave the higher fibre yield compare other two varieties bjri tossa pat-5 (3.20 tha-1; 3.14 tha-1and 3.12 tha-1 respectively) and o-9897 (3.05 tha-1; 2.99 tha-1and 2.99 tha-1 respectively) at manikganj , rangpur and jessore. references bbs. 2015. yearbook of agricultural statistics of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. second edn. john wiley and sons inc., new york. pp.304-307. hsu, s.t. and c.y. chi. 1976. studies on the effect different harvesting periods on yield and quality of jute fibre. field crop abs. 29(3): 190. islam, m.m. and m.s. ali. 2017. economic importance of jute in bangladesh: production, research achievements and diversification. intl. j. econ. theory appl. 4(6): 45-57. islam, m.m. and m.s. ali. 2017. agronomic research advances in jute crops of bangladesh. aascit j. biol. 3(6): 34-46. islam, m.m., k.r. haque, a.a. miah, n. nuruzzaman and m.a. rahman. 1995. response of stage of harvest to yield, yield components and quality of jute fibre. bangladesh j. jute fib. res. 20(1): 915. islam, m.m. and m. rahman. 2008. hand book on agricultural technologies of jute, kenaf and mesta crops. bangladesh jute research institute, manikmia avenue, dhaka-1207, bangladesh. p.92. islam, m.m. and n. uddin. 2019. research and development advances of jute seed in bangladesh: a review, haya saudi j. life sci. 4(2): 52-68. rahman, m.m., m.l. rahman, a.k. azad, m. rahman and m.m. hussain. 2003. impact of component technologies in jute production. bangladesh j. jute fib. res. 24(1-8): 21-26. weng, c.h., n.x. lai and b.f. shao. 1990. effect of harvesting dates on fibre yield and quality of kenaf and jute. field crop abst. 43(11): 1076. bangladesh agron. j. 2018, 21(2): 1-6 intercropping french bean with brinjal at varying planting system j.a. chowdhury1, md. mahfuz bazzaz2, s.s. kakon1, a.a. begum1 and most. mahbuba khanum2 1senior scientific officer, agronomy division, bangladesh agricultural research institute, joydebpur, gazipur 1701, bangladesh 2agricultural research station, bangladesh agricultural research institute, rajbari, dinajpu *corresponding author, email: jasminedaisy.bari@gmail.com (received: 7 november 2017, accepted: 9 april 2019) keywords: intercropping, french bean, brinjal, planting system abstract the experiment was carried out at the research field of agricultural research station, rajbari, dinajpur during rabi season of 2014-15 and 2015-16 to find out suitable crop combination for higher productivity and economic return. six different treatments viz. t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%) were evaluated. the results revealed that the highest mean fruit yield of brinjal (44.26 t ha-1) and french bean (20.96 t ha-1) was obtained in sole cropping of component crops. under intercropping, the highest brinjal yield (38.61 t ha-1) was recorded in brinjal normal row + 1 line french bean between brinjal, while, the highest french bean yield (16.06 t ha-1) in brinjal normal row + 2 lines french bean between brinjal. the highest mean brinjal equivalent yield (58.72 t ha-1) and land equivalent ratio (1.50) was also obtained in brinjal normal row + 2 lines french bean between brinjal. the highest gross return (tk. 4,69,760 ha1), gross margin (tk. 3,66,440 ha-1), and bcr (4.54) were obtained in brinjal normal row + 2 lines french bean between brinjal and the lowest in sole french bean. the overall results indicated that among the intercrop combinations brinjal normal row + 2 lines french bean between brinjal was found suitable for total productivity and economic return of the system. introduction intercropping system is an important feature of tropical agriculture. it is a cropping system which integrates crop production with soil conservation. benefits of intercropping may be briefed as: better use of resources, improvement of soil fertility by legume components of the system, soil preservation through covering the bare land between the rows, reduction of biotic and abiotic risks by increasing diversity, suppression of weed infestation. one of the advantages of this system is that it gives an assurance against crop failure which is common in developing countries. the value of intercropping system has been gaining recognition because of its ability to reduce damage caused by pest and diseases, ensure greater yield stability by producing some yield even though some of the component crops failed. it increases total productivity per unit area through maximum utilization of land, labor and growth resources (craufard, 2000; marshal about:blank 2 chowdhury et al. and willey, 1983). inclusion of legumes enhances crop and nitrogen yields of the non-legumes (wood and mayers 1987). brinjal is an important winter vegetable crop in bangladesh, which can be grown throughout the year. it is grown with wider spacing. so, in the inter-row space of brinjal french bean can be grown as intercrop for higher economic return as well as soil nutritious status can be improved. therefore, this experiment was conducted to find out suitable crop combination of brinjal with french bean for higher productivity and economic return. materials and methods the experiment was conducted at the research field of agricultural research station, rajbari, dinajpur during rabi season of 2014-15 and 2015-16. six different treatments were employed in this study viz. t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm ), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%). the experiment was laid out in randomized complete block (rcb) design with three replications. the unit plot size was 4.5 m 3.0 m. the land of the experimental plot was prepared into good tilth. fertilizers were applied @ 160-48-120-20-3-0.9 kg ha-1 n-p-k-szn-b for both the sole brinjal and intercrop combinations. except n and k, full amount of all other fertilizers were applied in pit before 1 week of transplantation. n and k was applied in 3 equal splits at 21, 35 and 50 dat in brinjal as ring method followed by irrigation. under intercropping situation no additional fertilizer was applied for french bean. but in sole french bean, fertilizers were applied @ 120-40-60-12-3 kg ha-1 n-p-k-s-zn, respectively. half of n and full amount of other fertilizers were applied at final land preparation and the rest n was top dressed at 35 days after sowing (das). thirty days old seedlings of brinjal was transplanted on 20 november 2014 and 08 november 2015, respectively and french bean was sown 10 days after planting of brinjal in line according to the treatment combinations. seeds of bari begun-10 and bari jharsheem-2 were used in both the years. intercultural operations like watering, weeding and pest control were done as and when required. first harvesting of brinjal was done at 119 dap (days after planting) and the harvesting was continued up to 208 dap. french bean was harvested three times at 87, 98 and 115 das. yield components of brinjal and french bean were taken from randomly selected 10 plants from each plot. yields of both the crops were taken from whole plot. treatments were compared in terms of land equivalent ratio and % land save using the formula developed by willey (1985). collected data of all crops were analyzed statistically by using mstat software packages and mean differences for each character were compared by least significant difference (lsd) test (gomez and gomez 1984). brinjal equivalent yields (bey) were computed using the formula of bandyopadhaya (1984). results and discussion yield attributes of brinjal the plant height, branch plant-1, fruit plant-1 and fruit weight plant-1 were significantly influenced by intercrop combination and sole cropping of brinjal in both the years (table 2). the tallest plant (125.20 cm in 2014-15 and 100.73 cm in 2015-16) was recorded in brinjal paired row (100%) + 4 lines french bean between brinjal (53%) and the shortest plant (115.50 cm in 2014-15 and intercropping french bean with brinjal 5 93.53 in 2015-16) in sole brinjal in both the year. the highest branch plant-1 (7.10) in 2014-15 was obtained in sole brinjal but there was no significant difference in 2015-16. the maximum number of fruit plant-1 (55.70 in 2014-15 and 36.53 in 2015-16) was recorded in sole planting of brinjal. similarly, the highest fruit weight plant-1 (2510.40 g in 2014-15 and 1792.60 g in 2015-16) was obtained in sole planting of brinjal and the lowest in brinjal paired row (100%) + 4 lines french bean between brinjal (53%) regardless of year. intercropping combinations had affected the fruit / plant and fruit weight. table 1. yield attributes of brinjal under sole and intercropping situation treatments plant height (cm) branch plant-1 (no.) fruit plant-1 (no.) fruit weight plant-1 (g) 2014-15 2015-16 2014-15 2015-16 2014-15 2015-16 2014-15 2015-16 t1 115.50 93.53 7.10 7.60 55.70 36.53 2510.40 1792.60 t3 122.00 98.00 5.40 7.33 46.30 30.87 2269.00 1434.26 t4 123.30 100.20 4.90 7.40 44.40 29.13 2007.80 1330.80 t5 124.96 99.80 5.10 6.73 45.20 27.53 2010.20 1251.47 t6 125.40 100.73 5.40 7.40 45.70 28.93 1988.30 1236.27 lsd (0.05) 1.83 2.71 1.88 ns 2.95 3.54 135.03 359.00 cv (%) 4.00 3.46 9.92 9.36 3.30 6.14 3.32 11.53 t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm ), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%). yield attributes of french bean the plant height and pod plant-1 significantly influenced by intercrop combination and sole cropping (table 1) but insignificant in branch/ plant and length of pods in both the years. the highest plant height (55.60 and 58.47cm) was observed in brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and the lowest (51.29 and 52.60cm) in sole cropping of french bean in both the years. the maximum pod plant-1 (33.87 in 2014-15 and 33.50 in 2015-16) was obtained in sole cropping of french bean and the minimum was in brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and brinjal paired row (100%) + 4 lines french bean between brinjal (40%) in 2014-15 and 2015-16, respectively. table 2. yield attributes of french bean under sole and intercropping situation treatment plant height (cm) branch plant-1 (no.) pod plant-1 (no.) pod length (cm) 201415 201516 201415 201516 201415 201516 201415 201516 t2 51.29 52.60 9.97 6.37 33.87 33.50 11.77 11.30 t3 53.81 56.70 8.45 7.33 31.04 32.07 13.36 12.17 t4 54.42 55.93 8.27 6.90 29.42 31.43 12.71 11.70 t5 55.60 58.47 8.12 7.23 27.00 25.80 13.43 12.13 t6 54.94 56.50 8.00 8.07 28.29 24.67 11.37 11.03 lsd(0.05) 2.78 3.12 ns ns 2.46 3.72 ns ns cv (%) 2.73 2.96 8.01 11.85 4.33 6.69 6.98 6.77 t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm ), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%). 2 chowdhury et al. yield, brinjal equivalent yield and ler the brinjal and french bean yield significantly influenced by intercrop combinations and sole sowing situations (table 3). the highest yield was recorded in sole cropping. the highest yield in sole crop might be due to the utilization of wider space and less competition for natural resources. ali et al. (2003) also reported similar result. under intercropping, the highest brinjal yield was recorded in brinjal normal row + 1 line french bean between brinjal might be due to less competition of different growth resources and the lowest in brinjal paired row (100%) + 4 lines french bean between brinjal (53%). yield reduction percent of brinjal in intercropping over sole is highest (23.04 in 2014-15 and 26.45 in 2015-16) in brinjal paired row (100%) + 4 lines french bean between brinjal (53%) and lowest (9.33 in 2014-15 and 16.77 in 2015-16) in brinjal normal row (100%) + 1 line french bean between brinjal (33%). on the other hand, the highest french bean yield under intercrop situation was recorded in brinjal normal row (100%) + 2 lines french bean between brinjal (66%) and the lowest in brinjal normal row + 1 line french bean between brinjal. yield reduction percent of french bean in intercropping over sole is highest in brinjal normal row (100%) + 1 line french bean between brinjal (33%) (33.49 in 2014-15 and 50.96 in 2015-16) and lowest (13.30 in 2014-15 and 32.73 in 2015-16) in brinjal normal row (100%) + 2 line french bean between brinjal (66%). the equivalent yield of brinjal was influenced by different cropping systems (table 4). brinjal equivalent yields (bey) in all intercropping systems were higher than sole brinjal indicating higher productivity of intercropping systems. similar results were mentioned by alom et al. (2013). among the treatments systems, maximum mean brinjal equivalent yield (bey) was 58.72 t ha-1 was obtained in brinjal normal row (100%) + 2 lines french bean between brinjal (66%), followed by brinjal normal row (100%) + 1 line french bean between brinjal (33%) over both brinjal and french bean sole sowing. in this study the mean ler values in all the intercropping systems were higher indicating the yield advantage of intercropping over sole cropping of brinjal (table 3). hence, intercropping rendered better productivity than their sole stand. the result was in agreement with the findings of juskiw et al. (2000). the land equivalent ratio (ler) was also higher in brinjal normal row (100%) + 2 lines french bean between brinjal (66%), and the lowest in brinjal paired row (100%) + 4 lines french bean between brinjal (53%). table 3. yield of brinjal and french bean, brinjal equivalent yield (bey) and land equivalent ratio (ler) under sole and intercropping situations treatment yield (t ha-1) bey (t ha-1) ler brinjal french bean 201415 201516 201415 201516 201415 201516 201415 201516 t1 47.56 40.97 47.56 44.27 1.00 1.00 t2 20.15 21.78 25.19 26.21 1.00 1.00 t3 43.12 34.10 13.40 10.68 59.87 53.66 1.57 1.39 t4 39.26 33.80 17.47 14.65 61.09 56.35 1.68 1.50 t5 38.75 31.59 14.23 12.68 56.53 47.44 1.53 1.36 t6 36.60 30.13 14.03 12.66 54.14 45.95 1.47 1.33 lsd (0.05) 4.26 4.99 1.29 2.51 cv (%) 5.49 7.86 4.32 9.07 t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%). intercropping french bean with brinjal 5 cost and return analysis the cost and return analysis of sole and intercropping of brinjal and french bean are presented in table 4. the result revealed that the highest gross return (tk. 469760 ha-1) and gross margin (tk. 366440 ha-1) were obtained in brinjal normal row (100%) + 2 lines french bean between brinjal (66%). the lowest gross return and gross margin were obtained from both sole brinjal and sole fernch bean. the highest benefit cost ratio (4.57) was also obtained from brinjal normal row (100%) + 2 lines french bean between brinjal (66%) and the lowest in sole french bean (2.69). table 4. cost and return analysis of brinjal and french bean under sole and intercropping situations (average of two years) treatment bey (t ha-1) gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr t1 45.91 354120 98320 255800 3.60 t2 25.70 209650 78000 131650 2.69 t3 56.76 454080 102040 353260 4.45 t4 58.72 469760 102792 366440 4.57 t5 51.98 415840 102320 314520 4.06 t6 50.04 400320 102430 298000 3.90 market price: brinjal tk 8 kg-1, french bean tk 10 kg-1 t1 = sole brinjal (75 cm x 60 cm), t2 = sole french bean (30 cm x 10 cm), t3 = brinjal normal row (100%) + 1 line french bean between brinjal (33%), t4 = brinjal normal row (100%) + 2 lines french bean between brinjal (66%), t5 = brinjal paired row (100%) + 3 lines french bean between brinjal (40%) and t6 = brinjal paired row (100%) + 4 lines french bean between brinjal (53%). conclusion the overall results indicated that among the intercrop combinations brinjal normal row + 2 lines french bean (30 cm x 10 cm) between brinjal was found suitable for total productivity and economic return of the system. references alom, m.s., b. l. nag, m. n. islam, f. ahmed and s. akther. 2013. performance of different crop species with pointed gourd (trichosanthes dioica roxb.) bangladesh j. agril. res. 38(3): 523-529. bandyopadhyay, s. n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. craufard, p. q. 2000. effect of plant density on the yield of sorghum-cowpea and pearl millet-cowpea intercrops in northern nigeria. exp. agric. 36(3): 379−395. gomez k. a. and a. a. gomez. 1984. statistical procedures for agricultural research, international rice research institute, los banos, philippines, john wiley and sons, new york. p. 680. juskiw, p. e., helm, j. h. and salmon, d. f. (2000). competitive ability in mixture of small grain cereals. crop sci. 40: 159-164. marshall, b. and r. w. willey. 1983. radiation interception and growth in an intercrop of pearl millet/groundnut. field crops res. 7(2): 141-160. willey, r. w. 1985. evaluation and presentation of intercropping advantages. exp. agric. 21(2): 119-133. about:blank about:blank 2 chowdhury et al. wood, i. m. and r. j. k. myers. 1987. food legumes in farming system in the tropics and subtropics. pp. 34-45. in food legume improvement for asian farming system. aciar proceedings series no. 18 (wallis, e.s. and d.e. byth, eds). canberra, australia: australian center for international agricultural research. bangladesh agron. j. 2019, 22(2): 161-169 production potential and competitive indices of mustard based intercropping with wheat under different row ratios p.k. biswas, h. chakma and t.s.roy department of agronomy sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka-1207 corresponding e-mail: parimalbiswas@hotmail.com (received: 19 february 2020, accepted: 30 march 2020) keywords: wheat, mustard, intercrop, wheat equivalent yield, bcr abstract an experiment was conducted at the agronomy research field, sher-e-bangla agricultural university, dhaka from november, 2015 to march, 2016 to study the performance of wheat-mustard intercropping as influenced by different row ratios. ten treatments were included in the study as, t1 (sole wheat), t2 (sole mustard), t3 (wheatmustard in 2:1 rows), t4 (wheat-mustard in 3:1 rows), t5 (wheat-mustard in 4:1 rows), t6 (wheat-mustard in 5:1 rows), t7 (wheat-mustard in 2:2 rows), t8 (wheat-mustard in 3:2 rows), t9 (wheat-mustard in 4:2 rows) and t10 (wheat-mustard in 5:2 rows). the experimental result indicatedthe significant variations of wheat yield by the wheatmustard intercropping system. the highest seed yield of wheat (3.4 t ha-1) was obtained from t1 (sole wheat) that identical with t4 (wheat-mustard in 3:1 rows) and similar with t9 (wheat-mustard in 4:2 rows). wheat yield gradually decreased with increasing mustard rows. the lowest seed yield (1.87 t ha-1) was obtained from t7 (wheat-mustard in 2:2 rows) which was statistically similar to t8 (wheat-mustard in 3:2 rows). the highest wheat equivalent yield (5.03 t ha-1) was obtained from t4 (wheat-mustard in 3:1 rows). treatment t4 (wheat-mustard in 3:1 rows) produced the highest ler (1.45). economic analysis of the different treatments showed that the highest gross return (tk. 120250.0 ha1), the highest net return (tk. 61178.0 ha-1) and bcr (2.04) from t4 (wheat-mustard in 3:1 rows). therefore, present study suggest that wheat and mustard intercropped in 3:1 rows showed the most compatible in respect of yield advantage and economic gain. introduction the practice of growing two or more crops simultaneously in the same field is called intercropping. it is a common feature in traditional farming of small landholders. it provides farmers with a variety of returns from land and labour, often increases the efficiency with which scarce resources are used and reduces the failure risk of a single crop that is susceptible to environmental and economic fluctuation. main purpose of intercropping is to produce a greater yield on a given piece of land by making use of resources in the way of maximum efficiency. the need for increased production of oilseed can also be fulfilled through their intercropping with wheat. besides intercropping of compatible crops use resources very efficiently and provides yield advantage over sole crops. in intercropping farming system, usually one main crop and one or more were used as added crops (sakaet al., 2007). according to sharma et al. (1993) mixture of cereals and legumes gave higher yield than their respective sole crops. similarly mandalet al. (1991) reported that wheat plus chickpea intercropping gave higher yield of wheat and water-use efficiency than wheat plus rapeseed intercropping. kerrio and aslam (1986) suggested that two crops of differing height, canopy and growth habits can be grown simultaneously with least competition. malik et al. (1998) reported that yield and yield components of wheat were significantly affected by association of chickpea, lentil and rapeseed while mikhovet al. (1991) stated that wheat yield in pure stand was significantly higher than mix cropping under rainfed conditions. 168 biswas et al. naziret al. (1988) also reported that intercropping of lentil (lens culinaris), sarson(brassica napus) and chickpea (cicerarietinum) decreased the wheat yield over wheat alone under un-irrigated conditions, however, the losses were compensated by their additional harvest in terms of net income. intercropping provides an efficient utilization of environmental resources, decreases the cost of production, provides higher financial stability for farmers, decreases pest damages, inhibits weeds growth more than monocultures, and improves soil fertility through nitrogen increasing to the system and increase yield and quality (francis et al., 1976; willey, 1979). it is now clear that the weeds could interfere with crops by increasing competition (for light, water, nutrients and space) and/or allelopathy. weeds declines crops yields and it lead to higher cost in agricultural productions (wanjariet al., 2001; pandya et al., 2005; singh and giri, 2001). there is need to develop the best cropping pattern to increase the production of mustard and wheat crop concomitantly. it has been shown that intercropping helps in increasing farm income (kalra and gangwar, 1980). sharma et al. (1986) reported that plant density showed significant difference by intercropping of wheat and mustard comparing to mono culture and found the highest land equivalent ratio (ler) by intercropping wheat and rape in a 1:1 row ratio. singh and pal (1994) reported that intercropping of wheat and mustard reduced the seed yield than their pure stands. whereas, ayisiet al. (1997) concluded from their experiment on canola-soybean intercropping that seed oil content increased compared with sole cropping. likewise, vermaet al. (1997) reported that intercropping of wheat and indian mustard gave maximum net return, benefit-cost ratio and land equivalent ratio. one of the most advantages of using herbicides is simplified weed control, but the use of herbicides, not only is costly but also selection of herbicide-resistant weed biotypes seriously become an environmental contamination factor now a day. herbicide use reduction is one of the main target of sustainable, and so several alternatives being investigated, including intercropping. the allelopathic potentiality of brassica to control weeds in wheat field was also reported (rahman et al., 2012; biswas et al., 2013 & 2014; biswas et al., 2014). the study was therefore undertaken to compare the performance of intercropping with different row ratios of wheat and mustard and to determine the possibility of increasing monetary advantage with wheat-mustard intercropping. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka during the period from november 2015 to june 2016. the farm belongs to the general soil type, shallow red brown terrace soils under tejgaon series. the land was above flood level and sufficient sunshine was available during the experimental period. the seeds of wheat variety bari gom-30 and mustard variety bari sarisha-16 were collected from bangladesh agricultural research institute (bari), joydebpur, gazipur. the experimental plot was ploughed and cross ploughed with the help of disc plough and harrow. the land was finally leveled with leveler to ensure uniform application of water. the lay-out of the experiment was done by maintaining 5m x 2m plot having 0.5m gap between two main plot as well as sub-plot; 1.0m between two replications. the whole plot was fertilized with the chemical fertilizers @ 100-80-30-20 kgha-1 of n, p2o5, k2o and s from their sources of urea, tsp, mop and gypsum, respectively. the whole amount of all fertilizers except urea was applied as a basal dose during final land preparation. the urea fertilizer was applied as two equal installments; 50% as basal dose and rest before flowering. the wheat and mustard seeds were sown on november 24, 2015. the spacing was maintained as per treatments.the experiment was laid out in a randomized complete block design with three replications.the treatments were: i) sole wheat (t1), ii) sole mustard (t2), iii) wheat-mustard in 2:1 row ratios (t3), iv) wheat-mustard in 3:1 row ratios (t4), v) wheat-mustard in 4:1 row ratios (t5), vi) wheat-mustard in 5:1 row ratios (t6), vii) wheat-mustard in 2:2 row ratios (t7), viii) wheat-mustard in 3:2 row ratios (t8), ix) wheat-mustard in 4:2 row ratios (t9) and x) wheatmustard in 5:2 row ratios (t10). water was ensured to the field in such a way that there should not have any scarcity of water that affects the experiment. two hand weedings were done for all the treatments. the field was infested by different insects and diseases those controlled by applying appropriate ways in time. the mustard was harvested on 100 days after sowing and wheat after 120 days of sowing. ten intercropping mustardwith wheat at different row ratios 169 plants per plot for both wheat and mustard were randomly selected for collecting yield contributing and other relevant data like plant height, no. of spikesplant-1, no. of grains spike-1 and 1000 grain weight for wheat and plant height, no. of siliquaeplant-1, no. of seedssiliqua-1 and 1000 seed weight for mustard. the seed yield of both the crops and wheat equivalent yield, land equivalent ratio, gross return, net return and benefit cost ratio were also recorded. statistical analyses were done by using the cropstat computer package and the mean differences among the treatments were compared by least significant difference test at 5 % level of significance following gomez and gomez (1984). results and discussion wheat plant height the plant height of wheat was significantly influenced by different row ratios of wheat and mustard intercrop with the advancement of plant age. at 25 das, there was less differences observed on plant height but it showed increasing trend with advancement of growth up to 75 das and then slightly increased up to harvest. the tallest plant was obtained from t4 (95.03cm) and the shortest plant from t9 (72.67cm) that similar to t7 (75.2cm) at harvest (figure1). t1 : sole wheat t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:1 rows t7 : wheat-mustard in 2:2 rows t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows fig.1. effect of wheat-mustard intercropping on plant height of wheat [lsd(0.05) = 5.91, 4.47, 8.28 and 3.71 at 25, 50, 75 das and atharvest, respectively]. no. of spikesplant-1 in intercropping with different row ratios, spike number of wheat was significantly affected (table 1) and the highest number of spikesplant-1(5.73) was obtained from t4 (three rows wheat and one row mustard) that followed by sole wheat (4.63) and t9(4.93). the lowest number of spikesplant-1 (2.27) was found from t6 (five rows wheat and one row mustard). this result was dissimilar to singh et al.(1995) who reported that the number of shoot or spike bearing tiller of wheat m-1 row length was the highest under pure stand and it decreasedsignificantly when the wheat was grown in any combination with indian mustard.mandalet al.(1991) also reported that the number of ear-bearing tillers in wheat was highest when grown alone. table 1. effect of wheat and mustard intercropping with different row ratios on no. ofspikesplant-1, 0 20 40 60 80 100 25 das 50 das 75 das at harvest t1 t3 t4 t5 t6 t7 t8 t9 t10 pl an t h ei gh t( cm ) days after sowing 168 biswas et al. no. of grainsspike-1, wt. of 1000 grains and grain yield of wheat treatments spikesplant-1 (no.) grainsspike-1 (no.) wt. of 1000 grains (g) grain yield (tha-1) t1 4.63 45.33 41.46 3.40 t3 3.37 37.67 40.12 2.63 t4 5.73 54.33 42.80 3.40 t5 3.77 36.33 37.07 2.47 t6 2.27 38.67 38.42 2.53 t7 3.70 28.33 40.35 1.87 t8 3.10 28.33 38.92 1.90 t9 4.93 45.00 38.27 3.10 t10 3.77 43.33 40.32 2.60 lsd(0.05) 0.61 11.20 5.14 0.06 cv (%) 5.35 9.71 4.46 7.79 t1 : sole wheat t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:1 rows t7 : wheat-mustard in 2:2 rows t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows number of grainsspike-1 the no. of grainsspike-1 showed significant differences on different row ratios of wheat-mustard intercropping system. treatment t4 (three rows of wheat and one row of mustard) resulted the highest no. of grainsspike-1 (54.33). the lowest no. of grainsspike-1 (28.33) resulted in t7 (two rows of wheat with two rows mustard) and t8 (three rows wheat with two rows mustard) (table 1). thousand-grain weight treatment t4 (three rows wheat and one row mustard) resulted the highest thousand-grain weight (42.8 g) that similar to other treatments except t5 (four rows wheat with one row mustard) which showed the lowest thousand-grain weight (37.07 g) that also similar to other combinations except t4 (table 1). grain yield there was significant difference observed on grain yield of wheat for different row ratios combinations. the highest grain yield (3.4 tha-1) was obtained from sole wheat and t4 (three rows of wheat and one row mustard). the lowest grain yield (1.87 t ha-1) was obtained from t7 (two rows wheat with two rows mustard) that similar to t8 (1.90 t ha-1) and t5 (2.47 t ha-1). it was observed that grain yield of wheat decreased with increasing mustard population (table 1). mustard plant height significant differences were observed on plant height in mustard when intercropped with wheat (figure 2). at 25 das, the highest plant height (21.52 cm) was found in t3 (two row wheat with one row mustard) and the lowest (11.31 cm) in t9 (four rows wheat with two rows mustard). at 50 das, the highest plant height (109.42 cm) was obtained by t7 (two rows wheat with two rows mustard) and the lowest (75.76 cm) at t5 (four rows wheat with one row mustard). at 75 das, t4 (three rows wheat and one row mustard) resulted the highest plant height (152.33 cm) and the lowest (136.1 and 134.7 cm) was found in t5 (four rows wheat with one row mustard) and t3 (two rows wheat with one row mustard), respectively.at harvest maximum plant height (170.60 cm) was recorded by t2 (sole mustard) and minimum (143.67cm) by t6 (five rows wheat with one row mustard). intercropping mustardwith wheat at different row ratios 169 t2 : sole mustard t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:1 rows t7 : wheat-mustard in 2:2 rows t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows fig. 2.effect of wheat-mustard intercropping on plant height of mustard [lsd(0.05) = 1.60, 15.15, 10.99 and 17.5 at 25, 50, 75 das and at harvest,respectively]. number of siliquaeplant-1 intercropping wheat with mustard showed significant variation on siliquae plant-1 of mustard (table 2). the highest number of siliquaeplant-1 (186.33) was recorded from sole mustard and minimum (56.67) given by the treatment t6 (five rows of wheat with one row mustard). table 2. effect of wheat-mustard intercropping on no. of siliquaeplant-1, no. ofseedssiliqua-1, 1000 seed weight and seed yield of mustard treatments siliquaeplant-1 (no.) seeds siliqua-1 (no.) wt. of 1000 seeds (g) seed yield (tha-1) t2 186.33 15.00 2.58 1.02 t3 94.33 7.67 2.21 0.33 t4 123.33 10.00 2.26 0.46 t5 83.00 7.67 2.13 0.18 t6 56.67 6.67 2.22 0.13 t7 126.00 9.67 2.18 0.29 t8 119.67 8.33 2.33 0.32 t9 127.33 10.00 2.02 0.31 t10 116.67 7.33 2.26 0.24 lsd(0.05) 34.31 4.85 ns 0.15 cv (%) 10.29 18.25 12.05 13.82 t2 : sole mustard t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:1 rows t7 : wheat-mustard in 2:2 rows t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows number of seeds siliqua-1 0 20 40 60 80 100 120 140 160 180 25 das 50 das 75 das at harvest t2 t3 t4 t5 t6 t7 t8 t9 t10 days after sowing pl an th ei gh t( cm ) 168 biswas et al. treatment t2 (sole mustard) resulted the highest (15.00) no. of seeds siliqua-1 that significantly varied with all other treatments and the lowest (6.67) number was recorded from t6 (five rows wheat with one row mustard) that similar to other treatments except t2 (table 2). wt. of 1000-seeds there was no significant variation in thousand-seed weight of mustard observed when intercropped with wheat (table 2). sharma et al. (1986) conducted an experiment of intercropping mustard with wheat during winter season on a sandy clay loam soil at pantnagar and observed that 1000-seed weight of mustard remain unaffected due to intercropping. seed yield seed yield of mustard resulted significant differences when intercropped with wheat. sole mustard showed the highest seed yield (1.02 t ha-1) might be due to larger area and population while the treatment t6 (five rows wheat with one row of mustard) resulted the lowest (0.13t ha-1) seed yield (table 2). wheat equivalent yield the wheat equivalent yield was significantly affected by wheat-mustard intercropping. (figure 3). the highest wheat equivalent yield (5.03 t ha-1) was obtained from t4 (three rows wheat and one row mustard) that similar to t9 (four rows wheat with two rows mustard). the lowest wheat equivalent yield (2.89 t ha-1) of observed in t7that similar to t8, t6 and t5. t1 : sole wheat t2 : sole mustard t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:1 rows t7 : wheat-mustard in 2:2 rows t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows fig.3. effect of wheat and mustard intercropping on wheat equivalent yield [lsd(0.05) = 0.85]. 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 wheat contribution mustard contribution treatments w he at eq ui va len ty ie ld (t ha -1 ) (t ha -1 ) intercropping mustardwith wheat at different row ratios 169 land equivalent ratio (ler) in wheat and mustard intercropped, significant differences was found in land equivalent ratio for different treatments (table 3). treatment t4 (three rows wheat with one row mustard) showed the highest (1.45) land equivalent ratio. cultivable land in the whole world is decreasing day by day and sole cropping needs more land than intercropping system. so, intercropped can served in an advantage by proper land utilization. vermaet al. (1997) reported higher land equivalent ratio in case of intercropping of wheat and indian mustard. gross return the gross return of wheat and mustard intercropping under different row ratios showedvariations among the treatments (table 3). it was found that the intercropping treatments always gave better gross return than the sole crops. the maximum gross return (tk. 120250.0 ha-1) was obtained from the treatment t4 (three rows wheat followed with one row mustard) and the minimum gross return (tk. 71787.5 ha-1) from t6 (five rows wheat and two rows mustard). table 3. effect of wheat-mustard intercropping on ler and other economic productivity treatments ler gross return (tk. ha-1) net return (tk. ha-1) bcr t1 1.00 79887.5 29395.5 1.58 t2 1.00 75017.6 19657.1 1.35 t3 1.09 95225.0 36153.0 1.61 t4 1.45 120250.0 61178.0 2.04 t5 0.90 77187.5 18115.5 1.31 t6 0.87 71787.5 12715.5 1.22 t7 0.83 76062.5 16990.5 1.29 t8 0.87 77412.5 18340.5 1.31 t9 1.22 102450.0 43378.0 1.73 t10 1.00 84400.0 25328.0 1.43 t1 : sole wheat t2 : sole mustard t3 : wheat-mustard in 2:1 rows t4 : wheat-mustard in 3:1 rows t5 : wheat-mustard in 4:1 rows t6 : wheat-mustard in 5:2 row t7 : wheat-mustard in 2:2 row t8 : wheat-mustard in 3:2 rows t9 : wheat-mustard in 4:2 rows t10 : wheat-mustard in 5:2 rows net return net return over variable cost was found encouraging in the intercropping treatments with proper row ratios. out of different intercropped treatments the maximum net return (tk. 61178.0 ha-1) was found in t4 (three rows wheat intercropped with one row mustard). it was also noted that intercrop always did not give the maximum net return if it was not planted by following proper row ratios (table 3). benefit cost ratio the treatment t4 (three rows wheat intercropped with one row mustard) gave the highest benefit-cost ratio (2.04) that followed by t9 (four rows wheat intercropped with two rows mustard), t3 (two rows wheat intercropped with one row mustard). the lowest benefit-cost ratio (1.22) was obtained from the t6 (five rows wheat with one row mustard) which also gave the lowest net return (table 3). 168 biswas et al. conclusion from the findings of the present experiment, it may be concluded that intercropping of wheat and mustard with three rows of wheat and one row of mustard was the most compatible and this combination gave the higher wheat equivalent yield (5.03 tha-1), ler (1.45), net return (tk. 61178.0 ha-1) and bcr (2.04) over normal planting of wheat. acknowledgement the author acknowledge the ministry of science and technology, govt. of the people’s republic of bangladesh for providing him fund under special allocation program to conduct the study. references ayisi, k.k., d.h. putnam, g.p. vance, m.p. russelle and d.l. allan. 1997. strip intercropping and nitrogen effects on seed, oil and protein yields of canola and soybean. agron. j. 81: 23-29. biswas, p.k., r. chakma, m.f. karim and i.j. irin. 2013& 2014. efficacy of brassica to control weeds in wheat.bangladesh j. weed sci.4&5: 1-6. biswas,p.k., m.m. morshed, m.j. ullah and i.j. irin. 2014.allelopathic effect of brassica on weed control and yield of wheat.bangladesh agron. j.17(1): 73-80. francis, c.a., c.a. flor and s.r. temple. 1976. adapting varieties for intercropping systems in the tropics. in: papendick r.i., p.a. sanches and g.b. triplett. (eds). multiple cropping. special publication number 27. pp.235-253. madison. american society of agronomy. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. international rice research institute. john wiley and sons, new york, pp.139-240. kalra, g.s. and b. gangwar. 1980. economics of intercropping of different legumes with maize at different levels of n under rainfed conditions. indian j. agron. 25: 181-185. keerio, h.k. and m. aslam. 1986. intercropping in maize crop. maize production manual, parc, islamabad. malik, m.a., m.a.hayat, s. ahamad and i. haq. 1998. intercropping of lentil, gram and rapeseed in wheat under rainfed conditions.sarhad j. agric.14(5): 417-421. mandal, b.k., s. dasgupta, and p.k. roy. 1991. effect of intercropping on yield components of wheat, chickpea and mustard under different moisture regimes. field crop absts. 39(10): 7025. mikhov, m., n. nankov and i. dimitrov. 1991. investigations of growing lentil sown in a mixture with wheat. rasteriv, dni-nauki. 28(7-10): 23-29. nazir, m.s., h.u.r. khan, g. ali and r. ahmad. 1988. inter/relay cropping in wheat planted in multi-row strips at uniform plant population. pakistan j. agric. res.9(3): 305-309. pandya, n., g.s. chouhan and v. nepalia. 2005. effect of varieties, crop geometries and weed management on nutrient uptake by soybean (glycine max) and associated weeds. indian j. agron. 50(3): 218220. rahman, a., p.k., biswas, m.s.a. sarder, m. hasanuzzaman and m. malek. 2012. allelopathic effect of brassica biomass on weed control and growth of wheat. bangladesh j. weed sci. 3(1 & 2): 5-10. saka, j.o., o.n. adeniyan, s.r. akande and m.o. balogun. 2007. an economic evaluation of intercropping african yam bean, kenaf and maize in the rain forest zone of nigeria. middle east j. sci. res. 2: 18. sharma, r.k., k.d. koranne, j.k. joseph, p. singh, v. prakash, r.k. mitlal, p. singh and v. prakash. 1993. vl massor 4: a new lentil variety for the hills of uttar pradesh. ind. fmg.42(10): 19-20. intercropping mustardwith wheat at different row ratios 169 sharma, k.c., y. sing, p.c. gupta, s.k. tripathy, a.k. bhardwaj and s.p. singh. 1986. plant population and spatial arrangement in wheat-mustard intercropping. indian j. agron. 31: 154-157. singh, s.s., m.d. ehsanullah, a.k. singh and b.k. singh. 1995. spatial arrangement in wheat (triticumaestivum) – indian mustard (brassica juncea) intercropping. indian j. agron.40: 91-93. singh, v.b. and g. giri. 2001. influence of intercropping and weed-control measures on suppression of weeds and productivity of spring season sunflower (helianthus annuus) and groundnut (arachishypogaea). indian j. agron. 46(3): 440-444. singh, o. and m. pal. 1994. performance of wheat + mustard intercropping system in limited irrigation conditions. ann. agric. res. 15: 255-259. verma, u.n., s.k. pal, m.k. singh and r. thakur. 1997. productivity, energetics and competition function of wheat (triticumaestivuml.) plus indian mustard (brassica junceal.) intercropping under varying fertilizer level. indian j. agron. 42: 201-4. wanjari, r.h., n.t. yaduraju and n. ahujak. 2001. nutrient uptake by sunflower (helianthus annuus) and associated weeds during rainy season. indian j. agron. 46(3): 541-546. willey, r.w. 1979. intercropping: its importance and research needs. part ii. agronomy and research approaches. field crops res. 32: 1-10. bangladesh agron. j. 2019, 22(2): 55-66 different tillage options and residue management for improvingcrop productivity and soil fertility in wheat-maize-rice cropping pattern m.i. hossain1, m.i. hossain2, m.a. ohab3, m.h.r. sheikh4 and b.l. nag5 1principal scientific officer, regional station, bwmri, rajshahi, 2director general, bwmri, nashipur, dinajpur, 3&4director (planning) & director (research), bari, gazipur corresponding e-mail: iliasrwrc@gmail.com (received: 29 december 2019, accepted: 18 march 2020) keywords: conservation tillage, residue retention, crop productivity, soil fertility and cropping pattern abstract a three yearsfield experiment was conducted at regional wheat research centre, shyampur, rajshahiduring 2014-15 to 2017-18 with an objective to observe the effects on soil fertility and performance of the crops under different tillage and residue management for rice-wheat (rw) systems by adding a third pre-rice crop of maize. the experiment was conducted in split plot design with three replication. the tillage options viz. (i) strip tillage (st) (ii) permanent bed (pb) and (iii) conventional (ct) tillage; two crop residue management, viz. (i) 0%=no residue and (ii) 30% residue retention were studied. the results indicated that keeping 30% crop residue in the field with minimum disturbance of soil had significant contribution on grain yield of wheat-maize-rice sequence compare to conventional practice of well-till without crop residue retention.the permanent bed planting system gave the highest yields of wheat (4.37 tha-1), maize (7.31 tha-1) and rice (4.40 tha-1) and followed by strip tillage and lowest in conventional tillage. among the residue management, 30% residue retention showed the highest yields of wheat (4.46tha1), maize (7.39 tha-1) and rice (4.69 tha-1). considering economic performance of all tillage systems, the permanent bed planting system performed the best among all other tillage options and followed by strip tillage. contrarily, 30% residue retention gave the highest yield and increased 0.12-0.14% organic matter into the soil with more productive.the results indicates that, both tillage systems coupled with 30% residue retention might be a good option for higher yield as well as soil fertility for wheat-maizetaman rice cropping pattern in drought prone areas of bangladesh. introduction crop production under permanent raised bed with residue retention is one of the best technologies for resource conservation in agriculture. upland crops like wheat and maize were established and grown successfully in permanent raised bed with wheat-maize-rice cropping pattern. land degradation and soil fertility decline are the main causes of the stagnation which reduces the agricultural production in many tropical countries, including those with intensive irrigated cropping systems. rice is transplanted in flat fields are typically ponded for long periods or continuously from transplanting until shortly before harvest. this negatively affects soil properties for the following non-puddled crop (hobbs and giri, 1998). a change from growing crops on the flat to raised beds offers more effective control of irrigation water and drainage. connor et al. (2002) suggested that permanent raised beds might offer farmers further significant advantages such as increased opportunities for crop diversification, mechanical weeding and placement of fertilizers; relay cropping and inter-cropping; and reduced tillage and water saving. raised beds are increasingly used in many developed and developing countries in 56 hossain et al. mechanized agriculture but have been introduced recently in bangladesh, with the aim of improving system productivity (talukderet al., 2002). inclusion of maize in the dry-wet transition of rice-wheat (rw) cropping system as a third crop may be another options of increasing cropping intensity, soil fertility and productivity of the system. although the non-rice season across the rice-wheat area is low rainfall, heavy pre-monsoonal rain can have disastrous effects on the third crop, such as maize or mungbean grown after wheat or before rice, both during establishment and grain filling because of water logging (timsina and connor, 2001; quayyumet al., 2002). due to lack of crop establishment technique and temporary water logging at reproductive stage, inclusion of a grain legume like mungbean in rice-wheat cropping system very often faces problems. bed planting may be a solution of this problem because raised beds not only facilitates irrigation but also drainage and therein lays their potential to increase the productivity of crops other than rice in the system. growing maize crops in a cropping system is beneficial not only for economic products but also for soil amelioration (singh and singh,1995). the common practice of rice in puddle soils destroys the soil physical structure that has implications for the following wheat crop (hobbs and gupta, 2000). crop residues are an important source of soil organic matter vital for the sustainability of agricultural ecosystems. about 25% of n and p, 50% of s and 75% of k uptake by cereal crops is retained in crop residues, making them valuable nutrient sources (singh, 2003). however, straw retention is not a common practice in the rw systems of bangladesh. wheat and rice straw are usually removed from fields for use as cattle feed and thatching material for houses or for fuel, leaving little for incorporation into the soil. gupta et al. (2002) observed that soil organic matter levels have declined in rice-wheat cropping systems, and optimization of nutrient uptake and absorption efficiency. limon-ortega et al. (2000) observed that permanent beds with straw retention had the highest mean wheat grain yields with positive implications for soil health. thus, management of crop residue and proper tillage options which may increase and maintain yields from the intensive rw system in bangladesh. therefore, this study was undertaken in a drought prone area in north-western part at rajshahi to evaluate the system productivity and soil property of intensive wheat-maize-rice crops sequence tested on ca practice compared to conventionally tilled systems. materials and methods a wheat-maize-rice cropping pattern was implemented whereas starting with wheat sown in november 25, 2014 and november 27, 2015 for wheat, maize crop sown on 3 april 2014 and transplanting rice on 27 july 2014 at the regional wheat research centre, shyampur (rwrc), rajshahi, bangladesh (24o3'n, 88041e, 18 m above sea level). the site has a subtropical climate and is located in agro ecological zone 11 (high ganges river flood plan) on flood-free high land, with course-textured, highly permeable soil (barc, 2012). the area receives 1072 mm mean annual rainfall, about 95% of which occurs from may to september (figure 1). tillage and residue management in wheat-maize-rice cropping pattern 57 fig. 1. weather data from nov 2014 to oct 2017 the trial involved a three-crop sequence i,e., rice-wheat-maize (rwm) planted on permanent raised beds (pb), fresh bed (fb) and conventional flats. rice was transplanted (one 25-days-old seedling per hill) with spacing 30 cm x 15 cm in late july and harvested in late november by hand. wheat was seeded at late november with 100 and 120 kg seed ha-1 for both raised beds and conventional flat, respectively and harvested in late march. after harvest of wheat, maize was planted in early april with seeding rate of 20 kg ha-1 and harvested in mid-july for both raised beds and conventional. the trial was originally established as pb, fb and conventional practices with two straw management (main plots-30% straw retention (sr) and 0% sr). the experiments were conducted on split plot design with three replication. the area of each subplot was 15 m2 (5m x 3m). the experiment consisted of 6 subplots with three tillage/straw treatments (30% sr + pb, 30% sr + ctp, 30% sr + st and 0% sr + ctp, 0% sr +pb and 0 % sr+st) with three replication. after planting the wheat or rice, straw from the preceding cereal crops was returned as mulch into the plot from which it had been removed at harvest. after harvesting and threshing, the rice and wheat straw were retained without chopping as standing way. the width of the beds was 60 cm (furrow to furrow) and the depth of the furrows on average was 15 cm. two rows of wheat (var. bari gom-30) or rice (var. brri dhan71) with a spacing of 30 cm, were planted by hand sowing on the beds, maize (var. nk-40) was sown by bed former in the furrows between the beds and indicator plant to assess microbial activity in the soil environment. the maize was harvested about 120 days after sowing (das). in ctp, wheat, rice and maize were planted in 20 cm, 30 x 15 cm (row x plant) and 60cm rows, respectively. a basal dose of p (20, 22 and 26 kg ha-1) from triple super phosphate, k (15, 33 and 35 kg ha-1) from muriate of potash and s (10, 11 and 20 kg ha-1) from gypsum was applied to rice, wheat and maize, respectively. in rice the entire amount of pks was broadcast before transplanting and mulching on both prb and ctp. for ctp the fertilizer was broadcast before tillage as is the usual practice. the recommended rate of n (80 kg ha-1for rice, 100 kg ha-1for wheat and 210 kg ha-1for maize) was applied as urea. with ctp, n was broadcast, while with beds it was banded on top of the soil between two rows in three equal installments 15, 30 and 45 days after transplanting of rice seedling, while wheat, two-thirds of the n was applied before seeding and the 0 20 40 60 80 100 120 20 14 n ov 9 16 23 2 10 17 25 20 15 s ep 9 16 24 31 9 16 24 20 16 ju ly 8 15 23 30 7 14 24 20 17 m ay 8 16 23 30 te m pe ra tu re @ r ai nf all tmax tmin total rainfall(mm) 58 hossain et al. remaining one-third at crown root initiation (cri). in maize, one-third n was applied as urea before seeding, one-third at eight leaves stage and remaining one-third at flowering stage. other fertilizers were applied before seeding in all three crops as recommended said doses. sufficient irrigation water was applied to fill the furrows between the raised beds. the flat plots were flood irrigated. weed control was done after the first irrigation for wheat by affinity application @ 2 g litre-1 of water, and at 25 and 45 days after transplanting for rice by ronstar @ 1ml litre-1of water. grain and straw yield were determined on a 5 m2 areas in each plot. statistical analysis of data the data were analyzed statistically following computer package mstatc and the significance of mean differences was adjusted by duncan’s multiple range test (dmrt) at p ≤ 0.05 (gomez and gomez, 1984). results and discussion before experimentation initial soil sample was collected and analyzed to know the nutrient status and the results were presented in table1. the soil was slightly alkaline (ph 7.8) havingvery low organic matter content (0.94%) and nitrogen, and zinccontent. the overall soil fertility status was low. table1. fertility status of initial soil sample of the experimental site at rwrc, bari, rajshahi sample ph om (%) total n (%) k p s zn b meq100g-1 µgg-1 value 7.8 0.94 0.05 0.21 10 23.3 0.14 0.27 critical level 0.12 0.12 10 10.0 0.60 0.20 interpretation slightly alkaline very low very low medium low opt. very low low grain yield and yield components of wheat grain yield is the cumulative effect of spike m-2, grains spike-1 and 1000 grain weight. yield and yield components data were shown in table 2. straw management were significantly influenced on grain yield and yield attributes in all three years but straw retention did not give any significant effect on spike m-2 and spikelet spike-1. the average three years maximum grain yield (4.40 t ha-1) was found from 30% straw retention plotover without straw retention plotin all three years. hobbs et al.(2000) found similar findings from their same experiments.. table 2. effect of straw management on yield and yield components of wheat in 2014-15 to 2016-17 straw management spikes m-2 spikelet spike-1 grains spike-1 tgw (g) grain yield (t ha-1) av. 3 years yield (t ha-1) 2014-15 2015-16 2016-17 0% straw 373 17.7 43.7 48.6 4.17 3.89 4.12 4.06 30% straw 372 18.4 50.6 53.9 4.60 4.39 4.48 4.46 t test ns ns ** ** ** ** ** ** grain yield and yield components of wheat grain yield is the cumulative effect of spike m-2, grains spike-1 and 1000 grain weight. yield and yield components data were shown in table 3. tillage systems were significantly influenced on grain yield and yield attributes in all three years but straw retention did not give any significant effect on yield and yield components. but strip till and permanent bed system did not any significant effect in all three tillage and residue management in wheat-maize-rice cropping pattern 59 years on wheat. the average three years maximum grain yield (4.40 t ha-1) was found from strip till system and it was at par with permanent beds (4.37 t ha-1) was found from all three years.hobbs et al.(2000)found similar findings from their same experiments. the lowest yield was also found from conventional practices in both the years. grain yield was higher due to higher yield attributes and get more photosynthesis with border effect. the minimum yield (4.07 t ha-1) was found from conventional tillage practice due to lower yield components and less photosynthesis with border effect. kataki(2001) found similar findings from both tillage options in wheat table 3. effect of tillage options on yield and yield components of wheat in 2014-15 to 2016-17 tillage options spikes m-2 spikelet spike-1 grains spike-1 tgw (g) grain yield (t ha-1) av. 3 years yield (t ha-1) 2014-15 2015-16 2016-17 conventional 368 17.2 43.2 49.6 4.07 3.62 3.78 3.82 permanent bed 352 18.8 50.3 54.9 4.62 4.19 4.31 4.37 strip tillage 357 18.5 50.8 54.7 4.68 4.17 4.35 4.40 cv (%) 13.14 5.34 7.59 3.65 12.44 8.745 9.15 7.65 lsd(0.05) ns ns 2.034 1.032 0.135 0.121 0.231 0.231 wheat grain yield and components under tillage options with residue management residue management with tillage systems was significantly influenced among the grain yield and yield components. grain yield is the cumulative effect of spike m-2, grains spike-1 and 1000 grain weight. average three years yield data were shown in table 4. the maximum grain yield was found (4.37 t ha1) was found from 30% residue retention with strip till systems and it was at par with (4.34 t ha-1) permanent bed system with 30% residue retention. table 4. interaction effect of tillage options and straw management on grain yield and yield attributes of wheat in 2014-15 to 2016-17 tillage options x n levels spikes m-2 spikelet spike-1 grains spike-1 tgw (g) grain yield (t ha-1) av. 3 years yield (t ha-1) 2014-15 2015-16 2016-17 conv. x 0 % sr 311 17.2 48.2 53.5 3.87 3.42 3.53 3.61 conv. x 30 % sr 329 18.7 51.5 54.7 4.04 3.61 3.78 3.81 pb x 0 % sr 317 17.7 48.4 53.4 4.24 4.03 4.12 4.13 pb x 30 % sr 321 18.7 52.4 54.5 4.41 4.21 4.41 4.34 st x 0 % sr 319 17.8 49.2 52.6 4.38 4.07 4.19 4.21 st x 30 % sr 325 18.4 52.3 54.2 4.48 4.15 4.47 4.37 cv (%) 11.34 5.34 7.59 3.65 5.65 10.24 9.67 7.25 lsd(0.05) 13.25 ns 0.231 ns 0.153 0.175 0.312 0.231 pb-permanent bed, ststrip tillage 60 hossain et al. grain yield was higher due to higher yield attributes, more tillering and border effect with sunlight. talukderet al. (2004) found more yield from both permanent and strip till system. minimum grain yield (3.61 t ha-1) was also found from conventional planting with 0% residue retention. minimum grain yield was also found by talukderet al. (2002) from same treatments.yield components were significantly influenced among the residue retention under different tillage options. maximum spike m2 (325) was found from 30% residue retention with fresh bed systems followed by (321) from permanent bed system with 30% residue retention. maximum grains spike-1 (52.4) was obtained from 30% straw retention with pb followed by (52.3) from st with 30% residue retention. talukderet al. (2004) found more spike m-2 and grains spike-1from both permanent and strip till system. minimum spike (311) and grains spike-1 (48.2) obtained from 0% residue retention with conventional tillage practices. maize grain yield and components under different tillage options the effect of different levels of tillage options had significant on all yield attributes and grain yield of maize (table 5). shifting from conventional to strip till and permanent bed resulted in significant yield increase of maize, which attributed from higher numbers of cobs m-2, cob length and grains cob-1. both strip till and permanent bed produced higher grain yield over conventional tillage. both strip till and permanent bed equally better in respect of improving cobs m-2, grains cob-1, thousand grain weightsbut not significant and thereby produced higher grain yield of maize. average two years yield data were shown in table 5,the maximum grain yield was found (7.34 t ha-1) was found from strip till systems and it was at par (7.31 t ha-1) in case of permanent bed system. lauren et al. (2006) found more yield from both permanent and fresh bed system. table 5. maize grain yield and yield attributes affected by tillage options tillage options cobs m-2 cob length (cm) grains cob-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 conventional 8.71 16.7 372.5 231.4 6.89 6.97 6.93 permanent bed 9.56 17.4 417.7 233.5 7.19 7.42 7.31. strip tillage 9.48 17.3 419.8 230.6 7.33 7.35 7.34 cv (%) 9.35 7.54 9.75 7.87 8.65 9.21 7.85 lsd(0.05) 0.231 ns 0.231 ns 0.112 0.121 0.114 maize grain yield and components under different straw retention the effect of different levels of straw retentionhad significant on all yield attributes and grain yield of maize (table 6). shifting from without straw retention to 30% residue retention resulted in nonsignificant yield increase of maize. both straw retention equally better in respect of improving cobs m2, grains cob-1, thousand grain weights but not significant and thereby produced higher grain yield of maize. average two years yield data were shown in table 6, the maximum grain yield was found (7.39 t ha-1) was found from 30% straw retention plot and it was similar to without straw retention plot. rwc-cimmyt (2003) found similar results from their experiments under residue retention. table 6. maize grain yield and yield attributes affected by straw retention straw retention cobs m-2 cob length (cm) grains cob-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 0 % sr 9.21 16.9 379.2 237.4 7.04 7.11 7.07 30 % sr 9.47 17.1 423.3 239.5 7.29 7.49 7.39 t test ns ns 9.44 ns ns 9.35 7.15 tillage and residue management in wheat-maize-rice cropping pattern 61 maize grain yield and yield attributes from the treatments the cumulative effect of different levels of tillage options and straw retention had significant on all yield attributes and grain yield of maize (table 7). shifting from conventional to strip till and permanent bed resulted in significant yield increase of maize, which attributed from higher numbers of cobs m-2, cob length and grains cob-1. both strip till and permanent bed produced higher grain yield over conventional tillage but straw retention did not get any significant effect on yield and yield attributes. conventional tillage with both 0 and 30% straw retention reduced the yield over strip till and permanent bed with straw retention. both strip till and permanent bed equally better in respect of improving cobs m-2, grains cob-1, thousand grain weight and thereby produced higher grain yield of maize. average two years yield data were shown in table 4. the maximum grain yield was found (7.40 t ha-1) was found from 30% residue retention with strip till systems and it was at par (7.39 t ha-1) in case of permanent bed system with 30% residue retention. grain yield was higher due to higher yield attributes whereas more border effect with sunlight. sayre et al. (2005) found more yield from both permanent and fresh bed system. minimum grain yield (6.93 t ha-1) was also found from conventional tillage with 0% residue retention. on the contrary, minimum grain yield was found by limon ortega et al. (2004) from both permanent and fresh bed system. yield attributes were significantly influenced among the residue retention under different tillage options. maximum cob m-2 (9.63) was found from 30% residue retention with permanent bed systems followed by (9.53) that of strip till system with 30% residue retention. table 7. interaction effect of tillage options and straw management on grain yield and yield attributes ofkharif 1 maize in 2015-16 to 2016-17 tillage options x straw retention cobs m-2 cob length (cm) grains cob-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 conv x 0 % sr 8.71 16.7 372.5 231.4 6.89 6.97 6.93 conv x 30 % sr 8.78 16.9 388.4 229.8 6.92 7.21 7.07 pb x 0 % sr 9.56 17.4 417.7 233.5 7.19 7.42 7.31 pb x 30 % sr 9.63 17.2 432.3 231.7 7.13 7.64 7.39 st x 0 % sr 9.48 17.3 419.8 230.6 7.33 7.35 7.34 st x 30 % sr 9.53 17.5 427.4 229.9 7.21 7.58 7.40 cv (%) 9.35 7.54 9.75 7.87 8.65 9.21 7.85 lsd(0.05) 0.121 ns 1.345 ns 0.425 0.542 0.526 pb-permanent bed, ststrip tillage maximum grains per cob (427.4) was obtained from 30% straw retention with st followed by (432.3) from pb with 30% residue retention. limon ortega et al. (2004) found more cob m-2 and grains cob from both permanent and fresh bed system. minimum cob m-2 (8.71) and grains per cob (372.5) obtained from 0% residue retention with conventional tillage practices. sayre et al. (2005) found similar findings from their experiments under permanent and fresh bed system. rice yield and yield components on different tillage options the rice crop was non-puddled transplanted both fresh and permanent bed but puddle transplanted in conventional tillage method had non-significant effect of conservation agriculture practices which imposed in previous wheat and maize crops were induced in rice crop. the effect of different levels of tillage options had significant on panicles hill-1, grains panicle-1 and 1000 grain weight but nonsignificant on hill m-1 and grain yield of rice. singh et al.(2003) found similar findings from their experiments. the transplanted amanrice was cultivated under the saturated to submerge soil conditions and the residual effect of ca did not resulted in significant impact on rice grain yield (table 8). only number of grains panicle-1 influenced by the treatments and both fresh and permanent bed produced higher grains panicle-1. maximum grain yield (4.40 tha-1) was found from permanent bed systems and 62 hossain et al. at par with fresh bed systems. table 8. yield and yield components of rice as affected from different tillage options in 2015-16 to 2016-17 tillage options hills m-2 panicles hill-1 grains panicle-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 conventional 29.2 17.6 130.7 24.3 4.34 4.12 4.23 permanent bed 30.7 18.4 135.2 25.1 4.47 4.32 4.40 strip tillage 30.4 18.2 134.8 24.9 4.41 4.29 4.35 cv (%) 7.25 8.45 8.785 9.75 9.87 10.37 8.325 lsd(0.05) ns 0.325 1.225 0.112 ns ns ns rice yield and yield components on different residue retention straw management had non-significant effect of conservation agriculture practices in rice crop. the effect of different levels of residue retention had significant on grains panicle-1 and 1000 grain weight but non-significant on hill m-1, panicle hill-1and grain yield of rice. singh et al.(2003) found similar findings from their experiments. the transplanted amanrice was cultivated under the saturated to submerge soil conditions and the residual effect of ca did not resulted in significant impact on rice grain yield (table 9). only number of grains panicle-1and 1000 grain weight influenced by straw retention plot produced higher grain yield but non-significant. maximum grain yield (4.69 tha-1) was found from 30% straw retention plot and at par with 0% straw retention plot. table 9. yield and yield components of rice as affected from different straw management plot in 201516 to 2016-17 straw retention hills m-2 panicles hill-1 grains panicle-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 0 % sr 32.2 18.1 130.5 24.4 4.52 4.47 4.49 30 % sr 33.7 18.8 136.7 25.5 4.67 4.72 4.69 t-test ns ns * * ns ns ns rice yield and yield components as interaction effect of tillage option and residue retention the rice crop was non-puddled transplanted both fresh and permanent bed but puddle transplanted in conventional tillage method but only the residual effect of ca practices which imposed in previous wheat and maize crops were induced in rice. the cumulative effect of different levels of tillage options and straw retention had significant on panicles hill-1, grains panicle-1and 1000 grain weight but nonsignificant on hill m-1 and grain yield of rice. singh (2003) found similar findings from their experiments. the transplanted amanrice was cultivated under the saturated to submerge soil conditions and the residual effect of ca did not resulted in significant impact on rice grain yield (table 10). only number of grains panicle-1 influenced by the treatments and both fresh and permanent bed produced higher grains panicle-1. maximum panicle hill-1(31.4) was found from 30% sr with permanent bed systems and at par with 30% sr with fresh bed systems. maximum grains panicle-1 (136.3) was obtained from 30% sr with permanent bed systems and at par with 30% sr with fresh bed systems. yadvinderet al. (2005) found non-significant effect under different tillage options with residue retention about four years. however, all the benefit of cropping systems and the intervention of ca practices may not be notice within two years cycle. long term study is necessary to understand the treatments effects on productivity of component crops in the systems. tillage and residue management in wheat-maize-rice cropping pattern 63 table 10. yield and yield components of rice crop as interaction effect of different tillage options and straw retention in 2015-16 to 2016-17 tillage options x straw retention hills m-2 panicles hill-1 grains panicle-1 tgw (g) grain yield (t ha-1) av. 2 years yield (t ha-1) 2015-16 2016-17 conv. x 0 % sr 29.2 17.6 130.7 24.3 4.34 4.12 4.23 conv. x 30 % sr 28.8 17.9 132.3 24.7 4.23 4.19 4.21 pb x 0 % sr 30.7 18.4 135.2 25.1 4.47 4.32 4.40 pb x 30 % sr 31.4 18.8 136.3 25.4 4.53 4.37 4.45 st x 0 % sr 30.4 18.2 134.8 24.9 4.41 4.29 4.35 st x 30 % sr 30.9 18.5 135.2 25.2 4.49 4.41 4.45 cv (%) 7.25 8.45 8.785 9.75 9.87 10.37 8.325 lsd(0.05) ns 0.325 1.225 0.112 ns ns ns soil properties after 3 cycles (years) both raised bed strip tillage options of soil condition was improved (table 11). soil ph, organic matter content, total n, available p, exchangeable k and mg were found higher in both raised bed tillage options than conventional tillage. after 3 years crop cycles, retention of straw from all three crops in the both tillage systems had increased the soil organic matter by 0.12-0.14%. since the both raised bed and strip tillage options produced more biomass in 30% crop residues from all crops were kept in the soil properties were improved. while some of the increase may have been due to formation of the beds from topsoil, the change in organic c increased as the rate of residue retention increased from 30%, indicating that straw retention also affected organic c on the beds. p, k and zn availability increased due to 30% sr with prb. after 3 years of ctp without residues, soil organic c had decreased by a few percent. kumar and goh (2000) reported that, in the longer term, residues and untilled roots from crops can contribute to the formation of som. after three years crop cycles, soil condition in permanent raised bed tillage options was better than conventional tillage. table 11. soil chemical properties analyzed after three years crop cycle tillage x sr ph organic matter (%) total n(%) available p(µg g1soil) exchangeable k(meq100g-1 soil) available s(mgg1soil) zn (µg g-1 soil) b (µg g-1 soil) conv. x 0 % sr 7.8 0.92 0.06 11.3 0.23 23.5 0.15 0.28 conv. x 30 % sr 8.0 0.98 0.07 13.5 0.25 24.2 0.17 0.31 pb x 0 % sr 7.9 0.93 0.08 11.8 0.24 23.7 0.14 0.27 pb x30 % sr 8.1 1.06 0.08 14.2 0.27 24.9 0.19 0.35 st x 0 % sr 7.8 0.94 0.07 11.5 0.22 23.6 0.15 0.27 st x 30 % sr 8.2 1.04 0.08 13.8 0.26 24.8 0.18 0.34 economic evaluation of conservation agriculture (ca) for economic evaluation, considered 20 farmers for permanent bed and 25 farmers for strip tillage in both the cases. from table 12, observed that total 25% cost saved of taman rice production in prb and 17% cost saved in new bed over farmers practice as well as more than double net return from both permanent and new bed system over farmers practice (fp). it also observed that economically higher return from both prb (28%) and new beds (34%) than fp. however, ca is more economically viable than farmers practice. singh and singh(1995) found similar results from their experimental field. 64 hossain et al. table 12. economic performance of ca for taman rice in 2012-16 farmers factors permanent (n=20) strip tillage (n=25) bed fp change strip till fp change tillage/land preparation 250 480 -47% 220 480 54% seed 140 200 -30% 140 200 -30% fertilizer & pest management 650 780 -16% 650 780 -16% irrigation 450 760 -40% 480 760 -36% weeding 395 550 -26% 420 550 -26% harvest 510 5600 -9% 520 560 -7% threshing 230 200 230 200 total costs 2625 3530 -25% 2920 3530 -17% yield (kg bigha-1) 760 590 28% 795 590 34% value &tk 10 kg-1 7600 5900 28% 7950 5900 34% net return 4975 2370 2605 5030 2370 2660 (2.1x) (2.12x) conclusion yield of component crops with in an intensive wheat-maize-rice cropping pattern was achieved under different tillage options. from the study it revealed that both tillage systems affected in terms of yield and yield components which ultimately produced maximum yield due to its more photosynthesis and border effect. soil organic matter in surface soil had increased by 0.14% after 3 years crop cycles with 30% sr from rice, wheat and maize crops. straw retention is an important component of soil management and may have long term positive impacts on soil quality. both strip tillage and permanent raised bed systems with 30% residues retained appears to be a very promising technology for sustainable intensification of rwm systems in drought prone areas of bangladesh. references barc (bangladesh agricultural research council). fertilizer recommendation guide, 2012. pp.10-12. connor d.j., j. timsina and e. humphreys. 2002. prospects for permanent beds for the rice-wheat system. in: ‘improving the productivity and sustainability of rice-wheat systems: issues and impacts’ (j.k. ladha, j.e. hill, j.m. duxbury, r.k. gupta and r.j. buresh eds.). vol. 65, pp.197-210. asa special publication, asa inc., madison, wi. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research (second edition).john wiley & sons, inc., irri, philippines, 680p. gupta, r.k., r.k. naresh, p.r. hobbs and j.k. ladha. 2002. adopting conservation agriculture in ricewheat systems of the indo-gangetic plainsnew opportunities for saving on water. paper presented at the water wise rice production workshop”, 5-10 april 2002, irri, philippines. hobbs p.r. and g.s. giri. 1998. reduced and zero-tillage options for establishment of wheat after rice in south asia. in ‘wheat prospects for global improvement by h. j. braun, kluwer academic press, dordrecht, the netherlands. hobbs, p.r and r.k gupta. 2000. ‘soil and crop management practices for enhanced productivity of the rice-wheat cropping system in the sichuan province of china. rice-wheat consortium paper series 9. (rwc, new delhi, india). kataki, p.k. 2001. the rice-wheat cropping system in south: trends, constraints and productivitya prologue, j. crop prod. 3: 1-26. tillage and residue management in wheat-maize-rice cropping pattern 65 kumar, k. and k.m. goh. 2000. crop residue management, effects on soil quality, soil nitrogen dynamics, crop yield and nitrogen recovery. adv. agron. 68: 197-319. lauren, j.g., j.m. duxbury, m.i. hossain, g. sah, a.s.m.h.m. talukder and c.a. meisner. 2006. permanent raised bed cultivation improves nitrogen and water use in rice-wheat cropping systems of south asia. 10th world science congress, usa. limon-ortega, a.l., k.d. sayre and c.a. francis. 2000. wheat nitrogen use efficiency in a bed planting system in northwest mexico. agron. j. 92: 303-308. limon-ortega, a.l., k.d. sayre and c.a. francis. 2004. wheat and maize yields in response to strawmanagement and nitrogen under a bed planting system. agron. j. 92: 295-302. quayyum, m.a., j. timsina, m.a.h.s. jahan, r.a. begum and d.j. connor. 2002. grain yield and system productivity for wheat-mungbean-rice and wheat-maize rice sequences in northern bangladesh. thai j. agric. sci. 35: 51-62. rwc-cimmyt. 2003. addressing resource conservation issues in rice-wheat systems of south asia: a resource book. (rwc-cimmyt, new delhi, india). sayre, k.d., a. limon and b. govaerts. 2005. experiences with permanent bed planting systems. byroth, c.h., fischer, r.a., meisner, c.a. (eds.). evaluation and performance of permanent raised bed cropping systems in asia, australia and mexico,proceedings of a workshop, griffith, australia, 1-3 march 2005. aciar proceedings no. 121, pp.12-25. singh, y. 2003. crop residue management in rice-wheat system. 2003. in: addressing resource conservation issues in rice-wheat consortium for the indo-gangetic plains.cimmyt, new delhi, india, p.153. singh, h. and k.p. singh. 1995. effect of plant residue and fertilizer on grain yield of dryland rice under reduced tillage cultivation. soil till. res. 34: 115-125. talukder, a.s.m.h.m., c.a. meisner, m.j. kabir, a.b.s. hossain and m. harun-ur-rashid. 2004. productivity of multi-crops sown on permanent raised beds in the tropics. in: new direction for a diverse planet: handbook and abstracts for the 4thinternational crop science congress, brisbane, australia, 26 september 01 october 2004, p.173. talukder, a.s.m.h.m., m.a. sufian and c.a. meisner. 2002. rice, wheat and mungbean yields in response to n levels and management under a bed planting system. in: proceedings published in the 17thworld congress of soil science, bangkok, thailand, v. 1, symposium no. 11, p..351. timsina, j. and d.j.connor. 2001. productivity and management of rice-wheat cropping systems: issues and challenges. field crops res. 69: 93-132. yadvinder, s., s. bijay and j. timsina. 2005. crop residue management for nutrient cycling and improving soil productivity in rice-based cropping systems in the tropics. adv. agron. 85:269407. keywords: conservation tillage, residue retention, crop productivity, soil fertility and cropping pattern bangladesh agron. j. 2017, 20 (1): 85-97 effect of nitrogen sources and weed management options on weed growth and crop yield of transplant aman rice r. ghosh1, m. salim1 and s. ahmed1, 2 1agronomy division, bangladesh agricultural university, mymensingh, bangladesh 2international rice research institute, bangladesh *corresponding author’s email: s.ahmed@irri.org key words: nitrogen source, sustainable crop production, herbicide, weed growth, rice yield. abstract a field study was conducted at the agronomy research field of bangladesh agricultural university, mymensingh, during the period of july to december, 2013 to evaluate the sources of nitrogen and weed management options on weed growth and rice yield. the experiment included four nitrogen sources (100% cowdung, 100% prilled urea, 100% urea super granule, 50% cowdung + 50% prilled urea) and four weed management options (weedy, application of herbicide at 3 dat, application of herbicide at 3 dat followed by hand weeding at 21 dat and weed free). sources of nitrogen and weed management options had significant effect on tiller number, biomass, spad value, panicle number, number of florets panicle-1, grain and straw yield, and weed biomass. the highest grain yield (5.40 t ha-1) was found in the treatment of 50% cowdung + 50% prilled urea with combination of season long weed free. although 100% prilled urea had significantly similar grain yield to 50% cowdung + 50% prilled urea, however, across the weed management options, 100% urea super granule and 100% cowdung had 15 and 27% lower grain yield. irrespective of the weed management options, 100% prilled urea had always higher weed biomass and 100% usg, 50% cowdung + 50% prilled urea, and 100% cowdung had 46, 35 and 19% lower weed biomass, respectively, compared with 100% prilled urea. in terms of rice yield and weed management, combined application of organic and inorganic source of nitrogen is better than only chemical or only organic source and pre-emergence herbicide followed by one hand weeding for transplanted aman rice. introduction in bangladesh, there are three distinct rice growing seasons such as aus, aman and boro. among them, aman covers more than half of the rice area accounting 5.61 million hectares with a production of 12.89 million tons of rice (bbs, 2013). it was always reported that in aman season yield gap between farmers and researcher is always higher and it is mainly due to imbalaced use of fertilizer and lack of inadequate pest management (salam et al., 2004). application of inorganic n fertilizer is considered to be most effective measures for improving rice production. unfortunately, fertilizer nitrogen (n) is not utilized efficiently in the world agriculture and the recovery of n in cereals, at global level is reported to be less than 40% (raun and johnson, 1999; raun et al., 2002). inorganic prilled urea (pu) is the principle source of n for rice production in bangladesh; however, in aman season crop can utilize less than 40% of applied nitrogen (ali et al., 2006). this is due to low recovery efficiency of n is associated with its high losses by leaching, denitrification, and volatilization (fageria and baligar, 2005). urea super granule (usg) is an alternate source of nitrogen fertilizer and becoming popular to the farmers. 86 ghosh et al. weeds are the greatest yield-limiting pest to rice production (ahmed and chauhan, 2014). global yield losses due to pests have been estimated approximately 40% where weeds caused the highest loss which is around 32% (rao et al., 2007). the weather condition of aman rice season in bangladesh is highly favorable for the enormous growth of weeds (ahmed and chauhan, 2015). the rice crops are severely infested with weeds and can reduce the grain yields by 16-48% for aman rice (irri, 1998). therefore, weed management is an important issue to obtain higher grain yield and better economic return. weeding in bangladesh commonly done by manually. in the large scale rice farming, herbicide based weed management has become viable option high costs of labor (anwar et al., 2012; singh et al., 2006). although herbicides are more reliable tools to manage weeds but sole dependence on herbicide may develop resistant biotypes and negative impacts on environment (fischer et al., 2000). therefore, effective weed management needs an integrated approach such as appropriate land preparation, use weed seed free tillage instruments, vigorous cultivars, planting density, row spacing, water management, fertilizer management, manual or mechanical weeding and herbicides (chauhan et al., 2015). nitrogen is a key nutrient which regulates the growth and development of plants and plays a significant role in the competitive balance between weeds and crops (raun and johnson, 1999). therefore, this study was undertaken to investigate the effect of sources of nitrogen fertilizer and weed management options on the crop and weed growth and crop yield of transplanted aman rice. materials and methods the experiment was conducted at the agronomy field, bangladesh agricultural university, mymensingh, during the periods from july to december 2013. the experimental field was located at 75°24' n, 50°90' e and altitude of 18 m above the mean of sea level. the experimental site belongs to agro-ecological zone 9 of old brahmaputra floodplain. the land was medium high and well drained, the soil was silty loam and low fertility level. the ph value of the soil was 6.7 and average organic matter content 1%. the experimental area was characterized by high temperature (average mean maximum temperature 35oc), high humidity and heavy precipitation with occasional gusty winds in kharif season (april to october) and scanty rainfall associated with moderately low temperature during the rabi season (november to march). historically the experiment site is under rice-fallow-rice cropping system. the experiment consists of four nitrogen sources [100% cowdung (10 t ha-1), 100% prilled urea (220 kg ha-1), 100% urea super granule (65 kg ha-1), and 50% cowdung (5 t ha-1) + 50% prilled urea (110 kg ha-1)] as main plot treatments and four weed management options [weedy, weed-free, herbicide (oxadiargyl 80 g ai ha-1), herbicide (oxadiargyl 80 g ai ha-1) followed by one hand weeding (1 hw at 21 days after transplanting (dat))] as sub-plot treatments. the experiment included in a split-plot design with three replications. full dose of tsp, mop, gypsum, and zinc sulphate were applied at the rate of 15, 48, 12, and 2.2 kg ha-1 of p, k, s, and zn, respectively. cowdung was applied according to treatment and leveling only those plots which received cowdung. thirty-five-day aged nursery seedling of var. brri dhan49 was transplanted on 27 july 2013 using 20cm x 15cm and three seedlings hill-1. prilled urea was applied three equal splits at 15, 35 and 55 dat. urea super granules was manually dibbling, one granules in the middle of four hills at 7 dat. experiment plots irrigated individually and kept continuous standing water up to 10 days before harvest. disease and insect management were need based. the plots which received herbicides, applied at 4 dat. one manual weeding plots were weeding at 21 dat. weedy plots allowed season long weed infestation and weed-free plots were kept completely weed-free by 4 times manual weeding. 87 effect of nitrogen sources and weed management options on weed growth and crop yield plant height was measured at 35 dat and at flowering from randomly selected 20 hills. rice tiller was counted from fixed 8 hills which covered 0.5 m-2 areas. to evaluate the weed management options on weed groups (i.e., grass, broadleaf, and sedge), weed biomass was measured at 35 dat and flowering from two randomly selected quadrates of 40 cm x 40 cm. weeds were separated by group, and their biomass was measured after oven drying the samples at 70 oc for 72 h. spad value was measured using spad meter from randomly selected 10 hills. one top most fully expanded leaf was selected from each hill and measured from tip, middle and base of the leaf. when 80-90% of the grains became golden yellow, the crop was considered to be matured. grain yield was converted to t ha−1 at 14% moisture content. data were analyzed using anova to evaluate differences between treatments and the means were separated using least significant differences (lsd) at the 5% level of significance (crop stat 7.2; international rice research institute, philippines). results and discussion plant height plant height did not influence by the interaction of nitrogen sources and weed management options, however, influenced by their individual effect (figure 1). the highest plant height (53.8 cm) was recorded when plots received 50% cowdung + 50% prilled urea at 35 dat. plot received with 100% prilled urea had statistically similar plant height to 50% cowdung + 50% prilled urea. fig.1. effect of nitrogen sources and weed management options on plant height at 35 dat and at flowering. cd (cowdung), pu ( prilled urea), usg, (urea super granule). vertical bars indicate lsd at 5% level of significant. 88 ghosh et al. the lowest plant height (50.3 cm) was recorded from plots received 100% cowdung. in case of weed management options, the maximum plant height (54.2 cm) was recorded from the weed-free plots followed by one hand weeding while lower (49.4 cm) plant height in weed control (figure 1). at flowering, plant height was maintained a similar trend to 35 dat. rice tiller tiller density significantly influenced by the interaction of nitrogen sources and weed management options (figure 2). tiller density at 35 dat had higher than at flowering and it was due to some tiller mortality after panicle formation. similar results were reported by hasanuzzaman et al., 2009; sudhir-yadav et al., 2011. tiller density was higher when plots received nitrogen source of 50% cowdung + 50% prilled urea with season long weed-free. the 100% prilled urea had significantly similar tiller density to 50% cowdung + 50% prilled urea treatment. the plots received nitrogen source 100% cowdung had always lower tiller density than the nitrogen sources of 50% cowdung + 50% prilled urea and 100% prilled urea, however, almost similar to 100% usg. the lowest panicle density was recorded in season long weedy treatment. the plots which received only herbicide had significantly higher tillers than the weedy treatment. fig. 2. effect of nitrogen sources and weed management options on rice tiller (number m-2) at 35 dat and at flowering. cd (cowdung), pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. 89 effect of nitrogen sources and weed management options on weed growth and crop yield rice biomass there was an interaction between nitrogen sources and weed management options on rice biomass (figure 3). irrespective of the nitrogen sources, weed-free treatment had always higher rice biomass than any other weed management options. across the nitrogen sources, herbicide followed by 1hw treatment had 6-13% lower rice biomass than the weed-free treatment, however, 4-19% higher than the treatment which received only herbicide. season long weedy treatment had always lower rice biomass. in case of nitrogen sources, 50% cowdung + 50% prilled urea had always higher rice biomass. at 35 dat, nitrogen source of 100% prilled urea had similar rice biomass to 50% cowdung + 50% prilled urea, however, at flowering it was lower. irrespective of the weed control options, 100% usg had significantly lower rice biomass than the 50% cowdung + 50% prilled urea and 100% prilled urea, however, significantly higher than the nitrogen source 100% cowdung. fig. 3. effect of nitrogen sources and weed management options on rice biomass (gm-2) at 35 dat and at flowering. cd (cowdung), pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. 90 ghosh et al. spad value spad value was significantly influenced by the interaction between n sources and weed management options (figure 4). considered with the n sources, at 35 dat, the highest spad value was recorded when plots received 50% cowdung + 50% prilled urea. plots received with 100% prilled urea had statistically similar spad value to 50% cowdung + 50% prilled urea. plots received with 100% cowdung produced the lowest spad value. in weed management options, weed-free treatment had always higher spad value. the treatment herbicide followed by 1 hw had significantly similar spad value to weed-free treatment. the lowest spad value was recorded in weedy treatment. similar to the result of 35 dat, at flowering, spad value almost maintain similar trend. when rice plants had more competition with weeds, spad values decreased and it was due to both weed and rice plants shared the available resources (awan et al., 2014). fig. 4. effect of nitrogen sources and weed management options on spad value at 35 dat and at flowering. cd ( cowdung); pu ( prilled urea),usg ( uurea super granule). vertical bars indicate lsd at 5% level of significant. 91 effect of nitrogen sources and weed management options on weed growth and crop yield weed biomass the common weed species found in the experiment field were comprised of grasses (cynodon dactylon, echinochloa crusgalli, leerisa hexandra, paspalam scrobiculatum) broadleaf (marselia guadrifolia, monochoria vaginalis, pistia stratioles) and sedges (cyperus iria, fimbristylis miliacea, scirpus juncoides). regarding the n sources, the highest total weed biomass was recorded when plots received 100% prilled urea (figure 5). fig. 5. effect of nitrogen sources and weed management options on total weed biomass (gm-2) at 35 d at and at flowering. cd (cowdung), pu (prilled urea), usg ( urea super granule). vertical bars indicate lsd at 5% level of significant. irrespective of the weed control options, at 35 dat, the nitrogen sources 100% usg, 50% cowdung + 50% prilled urea, and 100% cowdung had 54, 46 and 35% lower weed biomass, respectively, compared with 100% prilled urea. these values were 46, 35 and 19% at flowering. the dominant weed group found in the experiment was grass weed (figure 6). 92 ghosh et al. fig. 6. effect of nitrogen sources and weed management options on grass weed biomass (g m2) at 35 dat and at flowering. cd (cowdung), pu ( prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. at 35 dat, the highest grass weed biomass was found in nitrogen sources 100% prilled urea treatment. in weed control options, the nitrogen sources 100% usg, 50% cowdung + 50% prilled urea, and 100% cowdung had 53, 44 and 39% less grass weed biomass, respectively, compared with 100% prilled urea treatment. considered with the broadleaf weed, at 35 dat, the season long weedy treatment of all nitrogen sources had similar biomass, however, at flowering 100% pill urea had significantly higher biomass than other nitrogen sources (figure 7). considered with the sedge weed, the highest weed biomass was recorded when plots received nitrogen source of 100% prilled urea and the lowest in 100% cowdung (figure 8). when plots received weed control option herbicide followed by 1 hw, sedge biomass was almost zero. similar effect at flowering stage which might be due to the shedding effect of rice canopy. as such prilled urea influenced weed growth better than other sources. the results were consistent with the previous study. ( blackshaw, 2005; kirkland and beckie, 1998). 93 effect of nitrogen sources and weed management options on weed growth and crop yield fig. 7. effect of nitrogen sources and weed management options on broadleaf weed biomass (gm-2) at 35 dat and at flowering. cd (cowdung), pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. fig. 8. effect of nitrogen sources and weed management options on sedges biomass (gm-2) at 35 dat and at flowering. cd (cowdung) pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. 94 ghosh et al. yield and yield components there was a significant interaction between n sources and weed management options on panicles number (figure 9). in n sources, panicle number was always higher in weed-free by manual weeding. the weed management option herbicide followed by 1hw had significantly similar panicle number to weed-free treatment. only herbicide treatment had similar panicle number to herbicide followed by 1hw. in weed management options, the nitrogen source of 50% cowdung + 50% prilled urea had higher panicle number which was significantly similar to nitrogen source 100% prilled urea. compared with 50% cowdung + 50% prilled urea treatment, the nitrogen sources 100% usg and 100% cowdung had 10 and 19% fewer panicle number, respectively. effect of nitrogen sources and weed control option on florets panicle-1 was found that florets panicle-1 maintained almost similar trend to panicle number (figure 10). fig. 9. effect of nitrogen sources and weed management options on panicles (number m-2) at physiological maturity. cd (cowdung); pu(prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. fig. 10. effect of nitrogen sources and weed management options on floret (numbers panicle-2) at physiological maturity. cd (cowdung), pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. 95 effect of nitrogen sources and weed management options on weed growth and crop yield grain and straw yields were also influenced by the interaction of nitrogen sources and weed management option. irrespective of the weed management options, nitrogen source 50% cowdung + 50% prilled urea had always higher grain and straw yield (figure 11 and 12). although 100% prilled urea had significantly similar grain and straw yield to 50% cowdung + 50% prilled urea, however, across the weed control options 100% usg and 100% cowdung had 15 and 27% lower grain yield and 9 and 20% lower straw yield, respectively. in nitrogen sources, the weed-free treatment had always higher grain and straw yield. compared with weed-free treatment, the plots which received only herbicide had 20 and 18% lower grain and straw yield, respectively. fig. 11. effect of nitrogen sources and weed management options rice grain yield (t ha-1). cd (cowdung); pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. fig. 12. effect of nitrogen sources and weed management options on rice straw yield (t ha-1). cd (cowdung), pu (prilled urea), usg (urea super granule). vertical bars indicate lsd at 5% level of significant. 96 ghosh et al. use of 100% prilled urea is better than the 100% usg in terms of rice yield, however, prilled urea influence more weed growth than usg. so, the best n source was 50% cowdung + 50% prilled urea. although 100% prilled urea had similar yield to 50% cowdung + 50% prilled but 100% prilled urea stimulates weed growth. pre-emergence herbicide followed by 1 hw significantly controlled weed and found similar yield to weed free. though maximum yield was obtained from weed free plot but it was not feasible due to high cost involvement of manual weeding. therefore, the best weed management option is pre-emergence herbicide followed by one hand weeding. conclusion preemergence herbicides followed by on hand weeding (21das) is better weed management option for transplanted aman rice. acknowledgment the authors would like to express their thanks to agronomy division, bangladesh agricultural university (bau) for give opportunity to conduct this experiment. references ahmed, s., m. salim and b. s. chauhan. 2014. effect of weed management and seed rate on crop growth under direct dry seeded rice systems in bangladesh. plos one 9 (7):10.1371/ journal.pone.0101919. ahmed, s. and b. s. chauhan. 2014. performance of different herbicides in dry-seeded rice in bangladesh. sci. world j. 10.1155 / 2014 / 729418. ahmed, s. and b. s. chauhan. 2015. efficacy and phytotoxicity of different rates of 0xadiargyl and pendimethalin in dry-seeded rice (oryza sativa l.) in bangladesh. crop prot. 72: 169-174. ahmed, s., t. h. awan, m. salim and b. s. chauhan. 2015. economics of nitrogen and integrated weed management in dry seeded rice. j. ani. plant sci. 25 (6) 1675-1684. ali, m. a., j. k. ladha, j. rickman and j. s. lales. 2006. comparison of different methods of rice establishment and nitrogen management strategies for lowland rice. j. crop improv. 16: 173-189. anwar, m. p., a. s. juraimi, a. puteh, a. man and m. m. rahman. 2012. efficacy, phytotoxicity and economics of different herbicides in aerobic rice. acta agric. scandin. 62: 604-615. awan, t. h., b. s. chauhan and p. c. s. cruz. 2014. growth plasticity of junglerice (echinochloa colona ) for resource use when grown with different rice (oryza sativa) planting densities and nitrogen rates in dry-seeded conditions. weed sci. 62: 571–587. bbs. 2013. annual report 2012-13. bangladesh bureau of statistics. ministry of planning. government of the people's republic of bangladesh, dhaka. p. 238. blackshaw, r. e. 2005. nitrogen fertilizer, manure, and compost effects on weed growth and competition with spring wheat. agron. j. 97: 1612–1621. 97 effect of nitrogen sources and weed management options on weed growth and crop yield chauhan, b. s., a. ahmed, t. h. awan, k. jabran, and s. manalil. 2015. integrated weed management approach to improve weed control efficiencies for sustainable rice production in dry-seeded systems. crop prot. 71: 19-24. fageria, n. k., and v. c. baligar. 2005. enhancing nitrogen use efficiency in crop plants. adv. agron. 88: 97–185. fao. 2013. statistical yearbook. http://www.fao.org/docrep/018/i3107e/i3107e00.htm. accessed: june 19. frg 2012. fertilizer recommendation guide bangladesh. agricultural research council. farmgate, new airport road, dhaka 1215. p 274. fischer, a. j., c. m. ateh, d. e. bayer and j. e. hill. 2000. herbicide-resistant echinochloa oryzoides and e. phyllopogon in california oryza sativa fields. weed sci. 48: 225-230. hasanuzzaman, m., k. nahar, t. s. roy, m. l. rahman, m. z. hossain and j. u. ahmed. 2009. tiller dynamics and dry matter production of transplanted rice as affected by plant spacing and number of seedling per hill. acad. j. plant sci. 2:162–168. irri. 1998. international rice research institute. annual report for 1997. los bañs, laguna, philippines. p. 246. kirkland, k. j. and h. j. beckie. 1998. contribution of nitrogen fertilizer placement to weed management in spring wheat (triticum aestivum). weed technol. 12: 507–514. rao, a. n., d. e. johnson, b. sivaprasad, j. k. ladha, and a. m. mortimer. 2007. weed management in direct seeded rice. adv. agron. 93: 153-255. raun, w. r. and g. v. johnson. 1999. improving nitrogen use efficiency for cereal production. agron. j. 91: 357-363. raun, w. r., g. v. johnson, m. l. stone, r. w. mullen, k. w. freeman, w. e. thomason and v. lukina. 2002. improving nitrogen use efficiency in cereal grain production with optical sensing and variable rate application. agron. j. 94: 815-820. salam, m. a., f. ali, m. p. anwar and m. s. u. bhuiya. 2004. effect of nitrogen level and date of transplanting on the yield and yield attributes of transplanted aman rice under sri method. j. bangladesh agril. univ. 2: 31-36. singh, s., l. bhushan, j. k. ladha, r. k. gupta. a. n. rao and b. sivaprasad. 2006. weed management in dry seeded rice cultivated on furrow irrigated raised bed planting system. crop prot. 25: 487-495. sudhir-yadav, g. gill, e. humphreys, s. s. kukal and u. s. walia. 2011. effect of water management on dry seeded and puddled transplanted rice. part 1: crop performance. field crops res. 120: 112–122. bangladesh agron. j. 2020, 23(2): 69-80 estimation of temperature co-efficient of wheat for adjusting proper sowing time a.a. begum* 1 , m.a.k. mian 1 , j. rahman 2 , m.m. khanum 3 , m.z. ali 1 and r.r.saha 4 1 agronomy division, bari, gazipur, 2 rars, jamalpur, 3 ars, rajbari, dinajpur and 4 oilseed research centre, bari, gazipur *corresponding e-mail: luckyshamol6869@gmail.com (received: 30 september, 2020, accepted: 24 november, 2020) keywords: temperature co-efficient, sowing time, wheat, gdd, lai, dm, grain growth, yield abstract the field experiment was conducted at agronomy research field, joydebpur, gazipur (latitude: 23.999941, longitude: 90.420273), rars, jamalpur (latitude: 24.923025, longitude: 89.950111) and ars, rajbari, dinajpur (latitude: 25.63544, longitude: 88.65144) of bari during rabi of 2018 – 2019 to observe the growth behavior and yield of wheat as influenced by prevailing air temperature based on sowing time. there were five sowing dates viz., d1 = 10 november, d2 =20 november, d3 = 30 november, d4=10 december and d5=20 december. sowing date showed great influence on tdm production, lai, physiological maturity, yield and yield components of wheat. 30 november sowing produced the maximum tdm and lai followed by 20 november sowing. these parameters finally contributed to higher grain yield than earlier and later sowing date. the crop sown on 30 november took the longest period (105, 106 and 109 days, respectively) to attain the physiological maturity with the highest gdd (1639, 1638 and 1640 respectively) and 20 december sown crop took the shortest period (95 , 96 and 98 days respectively) to attain the physiological maturity with the lowest gdd (1530, 1528 and 1525 at joydebpur, jamalpur and rajbari, respectively).it was also found that 30 november sown crop produced the higher grain yield (4.90 t ha -1 , 4.99 t ha -1 and 5.03 t ha -1 at joydebpur, jamalpur and rajbari, respectively).the results revealed that 20-30 november sowing produced higher grain yield might be due to favourable air temperature for growth and development. late sowing after november 30 produced lower grain yield due to high temperature prevailed at the later growth stage (march) of wheat at joydebpur, jamalpur and rajbari region. the temperature co-efficient of wheat was estimated at 2.41 t ha -1 (1.95-2.89 t ha -1 ) indicated grain yield reduced 2.41 t ha -1 per 1°c increased of air temperature and effect of temperature on the grain yield of wheat was estimated at 81-84%. introduction wheat (triticum aestivum l.) is the most important crop in the world that excels all other cereals both in area and production (costa et al., 2013). it is also one of the most nutritious cereals that contributed to human diet putting it in the first rank to feed the world. in bangladesh, it is the second major cereal crop after rice as human food. while wheat is grown over a wide range of environments, it is common in the major wheat-producing countries for grain filling to occur when soil moisture is declining and temperature is increasing (asseng et al., 2010). wheat is primarily grown across the exceptionally diverse range of environments. the optimum temperature for anthesis and grain filling of wheat ranges from 12 to 22 °c. the optimum temperature required for wheat growing period is 20° to 25° c and the maximum temperature is 35 °c. if temperature is more than 30 °c at the time of maturity, it leads to force maturity which is responsible for yield loss (uddin et al., 2015). post-anthesis heat stress in wheat induces several physiological functions which eventually produce in lesser grain weight as a mailto:luckyshamol6869@gmail.com 70 begum et al. result of reduced grain filling period and starch synthesis duration or the combined effect of both. the organization for economic co-operation and development (oecd) (2003) focused on rises in temperature of 1.4 °c by 2050 and 2.4 °c by 2100 in bangladesh. islam (2009) estimated that temperature increases over the past 100 years for all over bangladesh at 0.62 °c (maximum) and 1.54 °c (minimum) occurred in february from 34 meteorological climate sites in bangladesh. those predictions of climate change and prediction of the effect of global warming is becoming the reality in bangladesh. thus the crop is being exposed to biotic and abiotic stresses due to adverse effect of climatic change. the seasonal and yearly variations in temperatures, humidity and rainfall distribution caused fluctuation in yield and production of wheat in last couples of years in bangladesh. experimentations have been done to improve wheat yield through manipulating sowing time (hossain et al., 2009). the sowing date of wheat is considered as most important factor limiting the wheat yield and it is reported that wheat yield decreased at the rate of 1.3% per day delay sowing after 30 november under the short spell of winter in bangladesh (ahmed et al., 1998). since, wheat is grown in winter season and winter is becoming warmer and shorter due to climate change, the dry matter production, grain growth and yield of wheat crop may be affected by higher temperature. sowing time of wheat may be adjusted to exploit the full yield potentiality exploring the agro-environmental benefit. therefore, the experiment was conducted to observe the growth behavior and yield of wheat as influenced by prevailing air temperature as well as other weather elements based on sowing time. materials and methods the experiment was conducted at the research field, joydebpur, gazipur (latitude: 23.999941, longitude: 90.420273), rars, jamalpur (latitude: 24.923025, longitude: 89.950111) and ars, rajbari, dinajpur (latitude: 25.63544, longitude: 88.65144) during rabi of 2018 – 2019. the soil was silty clay in texture at joydebpur (aez-28), silty loam at jamalpur (aez-9) and sandy loam at rajbari (aez-3). the treatments were five sowing date: d1 = 10 november, d2 =20 november, d3 = 30 november, d4=10 december and d5=20 december. the experiment was laid out in a rcb design with three replications and the unit plot size was 5m × 4 m in all locations. wheat seeds were sown as per treatment in line with maintaining 20 cm row to row spacing. fertilizers were applied @ 120-30-90-153-1 kg ha -1 of n-p-k-s-zn-b, respectively (barc, 2012), in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid. two third of urea and full doses of other fertilizers were applied at the time of final land preparation. the remaining one third of urea was top dressed at cri stage followed by irrigation in all locations. data on growth parameters like leaf area and dry matter accumulation were measured at different dates with 15 days interval at joydebpur location. to record dry matter weight and leaf area, one linear meter was sampled at 15, 30, 45, 60, 75 das and at harvest. different plant parts of the collected samples were separated and then oven dried at 80°c for 72 hours. leaf area was measured by an automatic leaf area meter (l13100 c, l1cor, usa). daily air temperatures were recorded for computing the growing degree days (gdd). the gdd was calculated using the following formula: gdd =∑ tbase where, t max and tmin are daily maximum and minimum air temperatures, respectively. tbase indicated base temperature of wheat (5°c). the gdd can be summed over days to indicate the amount of heat for growth that the crop has received over the period of the growing season (kumar et al., 2008). for estimation of physiological maturity and grain growth study, five spikes were harvested from each plot after anthesis starting from 5 days after anthesis at four days interval. it was continued up to 32 days after anthesis (daa). the harvested spikes were oven dried at 70°c for 72 hours. twenty grains of each spike were separated from the middle of each spike and then weight was taken. the crop was harvested at physiological maturity. the 10 november, 20 november, 30 november, 10 december and estimation of temperature co-efficient of wheat 71 20 december sowing crops were harvested on 3 march, 6 march, 13 march, 19 march and 28 march, respectively. yield contributing characters were recorded from one linear meter at the time of harvest. yield data were recorded by harvesting ten square meter area excluding border. data was analyzed statistically following mstat-c software package gomez and gomez (1984) and means were compared using lsd test at 5% level of significance. results and discussion effect of sowing date on leaf area index the lai was influenced by different sowing dates over time (fig. 1). the lai increased sharply and reached the peak at 60 das when the crop sown on 10, 20 and 30 november. on the other hand, lai increased sharply and reached the peak at 45 das when sown on 10 and 20 december then declined up to harvest. the reduction of lai after the peak might be due to leaf senescence. among the sowing dates, 30 november sowing showed the highest lai (4.0) at 60 das and it was higher throughout the growing period except at 45 das. this has happened due to optimum sowing time (30 november sowing) produced the highest lai across the different sowing dates. the lower lai was observed on 20 december sowing at all over growing period except 45 das. because leaf area of the crop sown on 10, 20 and 30 november increased up to 60 das due to getting longer vegetative phase and leaf area of the crop sown on 10, 20 december increased up to 45 das due to getting shorter vegetative phase. fig. 1. lai of wheat at different das as influenced by sowing dates effect of sowing date on tdm production the pattern of tdm accumulation in wheat over time was influenced by different sowing dates (fig. 2). the tdm of wheat increased slowly up to 45 das when crop sown on 10, 20 and 30 november. after 45 das dry matter accumulation rate increased rapidly up to harvest. in december sowing, tdm production increased slowly up to 30 das. after 30 das dry matter accumulation rate increased rapidly up to 75 das and then increased slowly till the harvest. the highest tdm accumulation m -2 was obtained from 30 november sowing at harvest followed by 20 november sowing and it was higher than other sowing throughout the growing period. the crop sown on 30 november got longer duration might be due to favorable temperature for growth and development as compared to other sowing dates and produced the maximum tdm. the results are in agreement with the findings of ahmad et al. (2005) and kamrozzaman et al. (2016) who stated that sowing dates had significant different on dry matter production due to variation of temperature. the lowest tdm was observed in 20 december sowing at all over the growing period. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 15 30 45 60 75 harvest l a i days after sowing 10 nov. 20 nov. 30 nov. 10 dec. 20 dec. 72 begum et al. fig. 2. tdm accumulation of wheat at different days after sowing as influenced by sowing dates effect of sowing date on dry matter partitioning pattern of dm distribution in different parts of wheat crop in response to planting dates have shown in fig. 3. irrespective of treatments, the difference in dry weight of leaf, stem and spike of wheat was minimum at early growth stages and widened with the advancement of growth. sowing dates had pronounced effect on dm distribution of wheat over the growth stages. pattern of dm distribution of wheat was similar in all the sowing dates such that allocation of assimilates to leaves and stems increased to a peak and then decreased with concomitant increase in allocation to reproductive organ (spike). irrespective of sowing dates, dry matter distribution to leaf of wheat peaked at 60 das when sown on 10, 20 and 30 november and peaked at 45 das when sown on 10 and 20 december. on the other hand, stem dry matter distribution of wheat peaked at 75 das at all sowing dates. the highest leaf and stem dry matter was produced by 30 november sowing and the lowest leaf and stem dry matter was produced by 20 december sowing at all over the growing period. the reduction in dry matter of vegetative parts (leaf + stem) after peak might be due to remobilization of stored assimilates into the grain of wheat. the highest spike dry matter was produced by 30 november sowing and the lowest spike dry matter was produced by 20 december sowing. it might be due to maximum duration (physiological maturity) was recorded in 30 november sowing prevailing optimum temperature in vegetative and reproductive phase. on the other hand, early sown crop got shorter vegetative phase which accumulated lower dm and delayed sown crop got longer vegetative phase which accumulated higher dm along with profuse tillering and shorter reproductive phase due to higher temperature prevailed in later stage. 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest t d m a cc u m u la ti o n ( g m -2 ) days after sowing 10 nov. 20 nov. 30 nov. 10 dec. 20 dec. estimation of temperature co-efficient of wheat 73 a.10 november b. 20 november c. 30 novemver d.10 december e. 20 december fig. 3. dry matter distribution pattern of wheat as affected by sowing date at joydebpur dry matter distribution pattern of wheat at harvest in response to sowing dates at joydebpur have shown in fig. 4.sowing dates had pronounced effect on dm distribution at harvest of wheat. the highest leaf, stem and spike dry matter was produced by 30 november sowing followed by 20 november sowing. the lowest leaf, stem and spike dry matter was produced by 20 december sowing followed by 10 december sowing. the crop sown on 30 november got longer duration due to 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest d m a cc u m u la ti o n ( g / m -2 ) days after sowing spike stem leaf 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest d m a cc u m u la ti o n ( g m -2 ) days after sowing spike stem leaf 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest d m a cc u m u la ti o n ( g m -2 ) days after sowing spike stem leaf 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest d m a cc u m u la ti o n ( g m -2 ) days after sowing spike stem leaf 0 200 400 600 800 1000 1200 1400 1600 15 30 45 60 75 harvest d m a cc u m u la ti o n ( g m -2 ) days after sowing spike stem leaf 74 begum et al. favourable temperature for growth and development as compared to other sowing dates (table 3) and produced the maximum tdm (leaf dry matter=178 g m -2 , stem dry matter=528 g m -2 and spike dry matter =736 g m -2 ) whereas, 20 december sowing produced the minimum tdm (leaf dry matter=149g/m 2 , stem dry matter=444 g m2 and spike dry matter =459 g m -2 ). thirty november sowing produced 51% spike dry matter, 37% stem dry matter and 12% leaf dry matter of tdm which was 60%, 19% and 19% higher than those of 20 december sowing (fig.4). fig.4. dry matter distribution pattern of wheat at harvest as affected by sowing date at joydebpur effect of sowing date on grain growth effect of sowing date on grain growth of wheat at joydebpur has been presented in fig. 4. among the different sowing dates, 30 november sowing exhibited higher grain growth in all over the grain filling period. it might be due to prevailing optimum air temperature on 30 november sowing. the crop sown on 20 november to 30 november exhibited higher trend of grain growth as compared to earlier and later sowing (10 november, 10 december and 20 december sowing).grain growth reached peak at 30 days after anthesis (daa) when the crop sown on 30 november. the maximum grain weight (52.0 mg/grain) was observed at 30 daa when crop sown on 30 november sowing followed by 20 november sowing at 32 daa. higher grain growth duration was observed at 10 november sowing but did not produce the maximum grain weight. it might be due to longer vegetative phase (75 days) gained maximum dry matter with lower temperature in 30 november sowing which produced the maximum grain weight of wheat. the crop sown on 10 november took the maximum grain growth duration (33 days) but shorter vegetative phase (69 days) with higher air temperature gained comparatively lower dry matter which failed to produce higher grain weight. the lowest grain weight (40.0 mg/grain) was observed at 21 daa on 20 december sowing. it indicated that grain weight reduced in late sown condition due to higher air temperature prevailed at later growth stage (march) shortening the growth period of wheat. similar results were also have been reported by mian et al. (2016) and khan and aziz (2015). they reported that grain growth was maximum in 30 november sowing followed by 15 november sowing while the lowest in 30 december sowing. 151 168 178 151 149 483 523 528 462 444 585 726 736 483 459 0 200 400 600 800 1000 1200 1400 1600 10 nov. 20 nov. 30 nov. 10 dec. 20 dec. d ry m a tt e r p a rt ir io n in g ( g m -2 ) sowing date spike stem leaf estimation of temperature co-efficient of wheat 75 fig. 4. grain growth of wheat as influenced by sowing dates at joydebpur location effect of sowing date on physiological duration, mean air temperature and gdd duration, mean air temperature and growing degree day (gdd) for anthesis and physiological maturity of wheat as affected by sowing date have been presented in table 1. temperature is an important factor which influences duration of different growth stage of wheat. in joydebpur, the shortest vegetative phase (69 days) with the lowest gdd (1074) was observed in 10 november sowing due to prevailing higher mean temperature (20.6°c) and the longest vegetative phase (75 days) with higher gdd (1115) was observed in 30 november sowing due to prevailing lower mean air temperature (19.9°c). similar trend was observed in jamalpur and rajbari location. the longest vegetative phase was observed in rajbari and the shortest vegetative phase was observed in joydebpur due to comparatively lower temperature prevailed in rajbari than other two locations during cropping period. on the other hand, the longest reproductive phase (33 days with 512 gdd) was observed in 10 november sowing due to prevailing lower mean temperature (20.5°c) and the shortest reproductive phase (21 days with lowest gdd 420) was observed in 20december sowing due to prevailing maximum mean air temperature (25.0°c) followed by 10 december sowing (24 days with 438 gdd due to prevailing mean air temperature 23.2°c) in joydebpur shown (table 1 and table 2). similar trend was observed in jamalpur and rajbari locations. as a result, 20 december sowing took the minimum duration (95 days at joydebpur, 96 days at jamalpur and 98 days at rajbari to reach physiological maturity with minimum gdd (1530, 1528 and 1525 at joydebpur, jamalpur and rajbari, respectively) and 30 november sowing took the maximum duration to reach physiological maturity with maximum gdd followed by 20 november sowing in all the locations (table 3). it might be due to comparatively higher temperature prevailed at the earlier and later sowing than 20-30 november sowing. longer duration (105 days at joydebpur, 106 days at jamalpur and 109 days at rajbari, respectively) due to prevailing lower temperature (20.4°c, 20.3°c and 19.1°c at joydebpur, jamalpur and rajbari, respectively) with higher gdd (1639, 1638 and 1640 at joydebpur, jamalpur and rajbari, respectively) produced the higher grain yield. the result of the present experiment was also supported by (ahmed et al., 2015). they reported that higher gdd produced the higher grain yield in maize production. 0 10 20 30 40 50 60 4 8 12 16 20 24 28 32 36 40 g ra in w t. ( m g g ra in -1 ) days after anthesis 10 nov. 20 nov. 30 nov. 10 dec. 20 dec. 76 begum et al. table 1. required duration, mean temperature and gdd for vegetative phase as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date vegetative phase (seeding to anthesis) duration (days) mean air temperature (°c) growing degree day (gdd) joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 nov. 69 69 71 20.6 20.5 19.2 1074 1067 1061 20 nov. 72 73 76 20.1 20.0 18.7 1089 1097 1100 30 nov. 75 76 77 19.9 19.6 18.4 1115 1113 1097 10 dec. 74 75 76 19.9 19.7 18.5 1101 1105 1099 20 dec. 74 75 76 20.0 19.8 18.8 1110 1112 1108 table 2. required duration, mean temperature and gdd for reproductive phase as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date reproductive phase (anthesis to physiological maturity) duration (days) mean temperature (°c) growing degree day (gdd) joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 nov. 33 33 35 20.5 20.5 19.4 512 513 514 20 nov. 32 32 33 21.0 20.9 20.4 514 510 508 30 nov. 30 30 32 22.5 22.5 22.0 524 525 543 10 dec. 24 25 26 23.2 23.0 22.6 438 451 458 20 dec. 21 21 22 25.0 24.8 24.0 420 416 417 table 3. required duration, mean temperature and gdd for physiological maturity as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date crop duration (seeding to physiological maturity) duration (days) mean temperature (°c) growing degree day (gdd) joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 nov. 102 102 106 20.5 20.5 19.3 1586 1580 1575 20 nov. 104 105 109 20.4 20.3 19.2 1603 1607 1608 30 nov. 105 106 109 20.4 20.3 19.1 1639 1638 1640 10 dec. 98 100 102 20.7 20.6 19.6 1539 1556 1557 20 dec. 95 96 98 21.1 20.9 20.0 1530 1528 1525 yield and yield attributes yield and yield contributing characters of wheat in all locations have been presented in table 4, table 5 and table 6. the maximum spikes m -2 was observed in 30 november sowing and the lowest in 20 december sowing in all locations. the maximum spike length was obtained from 30 november sowing which was identical with 20 november and 10 november sowing and the minimum spike length from 20 december sowing followed by 10 december sowing in all locations. higher grains spike -1 (47.2, 48.9 and 49.9 at, respectively) was observed in 30november sowing which was statistically similar with 20 november and 10 november sowing and the lowest (38.2, 40.6 and 41.0 at joydebpur, jamalpur and rajbari, respectively) was observed in 20 december sowing followed by 10 december sowing in all locations. the highest 1000-grain weight (50.73 g, 52.35 g and 52.59 g respectively) was observed in 30 november sowing which was statistically similar with 20 november and 10 november sowing and the lowest (42.27, 42.48 and 46.11g at joydebpur, jamalpur and rajbari, respectively) was observed in 20 december sowing followed by 10 december sowing in all locations. the maximum grain yield (4.90 1 , 4.99 and 5.03 t ha -1 , respectively) was observed in 30 november sowing which was statistically similar with 20 november sowing due to cumulative effect of better yield components and the lowest grain yield (3.15, 3.29 and 3.39 t ha -1 at joydebpur, jamalpur and rajbari, respectively) was observed in 20 december sowing followed by 10 december sowing due to cumulative effect of poor yield components in all locations. it was observed that 30 november sowing received lower estimation of temperature co-efficient of wheat 77 temperature during cropping period that caused longer crop growth duration and ultimately produced higher tdm and translocation of higher tdm to grain. it might be 30 november sowing probably received favorable environment mainly optimum temperature resulting better vegetative growth of the plants which ultimately led to the better flowering, grain filling and finally increased grain yield. on the other hand, the lowest grain yield was observed in 20 december sowing. it was founded that 20 december sowing crop received cool temperature at early growth stage which produced profuse tillering and higher temperature at reproductive phase that hastened maturity and reduced tdm production and translocation of less dry matter to the reproductive organ (grain).grain yield of wheat was found higher at rajbari than other two locations. it might be due to maximum and minimum temperature prevailed during wheat growing period at rajbari was lower than other two locations (fig. 5). table 4. plant height, spikes m -2 and spike length (cm) of wheat as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date plant height (cm) spikes m-2 (no.) spike length (cm) joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 november 99.7 95.6 97.9 393 438 416 9.9 9.7 9.9 20 november 97.2 94.7 95.0 413 443 428 10.1 9.9 10.1 30 november 96.9 89.8 90.8 415 448 432 10.1 10.1 10.3 10 december 95.8 85.3 89.4 328 342 335 8.8 8.9 8.7 20 december 89.5 82.6 86.4 315 335 325 9.0 9.1 9.2 lsd (0.05) ns ns ns 51.56 66.17 52.69 0.52 0.57 0.82 cv (%) 5.31 5.99 7.30 7.34 8.76 7.23 2.87 3.19 4.52 table 5. grains spike -1 , 1000-grain wt. and grain yield of wheat as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date grains spike-1 (no.) 1000-grain wt. (g) grain yield (t ha-1) yield reduction over 30 nov. sowing (%) joy. jam. raj. joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 november 44.5 45.1 47.8 47.40 48.91 50.18 3.97 4.07 4.17 18.9 18.4 17.1 20 november 46.7 47.4 49.5 49.07 51.09 51.38 4.77 4.80 4.95 2.7 3.8 1.6 30 november 47.2 48.9 49.9 50.73 52.35 52.59 4.90 4.99 5.03 10 december 38.5 42.0 42.8 42.93 42.97 46.44 3.29 3.34 3.41 32.9 33.1 32.2 20 december 38.2 40.6 41.0 42.27 42.48 46.11 3.15 3.29 3.39 35.7 34.1 32.6 lsd (0.05) 4.85 4.06 4.32 4.60 4.24 3.81 0.33 0.48 0.75 cv (%) 5.99 4.78 4.97 5.26 4.74 4.11 4.35 6.19 9.48 yield reduction was observed (3-36, 4-34 and 2-33 % at joydebpur, jamalpur and rajbari, respectively) for earlier and later sowing over 30 november sowing. the result of the present study was also supported by kamrozzaman et al. (2016). the variations in yield and yield contributing characters of wheat due to sowing date were also observed by gul et al. (2012) and uddin et al. (2015). similar trend was also observed in straw yield, biological yield and harvest index (hi). 78 begum et al. table 6. straw yield, biological yield and harvest index of wheat as affected by sowing date during rabi of 2018-2019 (joydebpur, jamalpur and rajbari) sowing date straw yield (t ha-1) biological yield (t ha-1) hi (%) joy. jam. raj. joy. jam. raj. joy. jam. raj. 10 november 4.63 4.700 4.07 8.600 8.767 8.98 46.12 46.40 46.38 20 november 5.35 5.347 5.08 10.13 10.15 10.53 47.13 47.31 47.02 30 november 5.48 5.543 5.36 10.38 10.53 10.68 47.24 47.32 47.03 10 december 3.89 3.977 3.34 7.180 7.32 7.42 45.82 45.67 45.89 20 december 3.82 4.120 3.29 6.963 7.41 7.42 45.18 44.41 45.62 lsd (0.05) 0.31 0.39 1.07 0.63 0.80 1.49 cv (%) 3.55 4.45 13.44 3.86 4.79 8.79 fig. 5.weekly maximum and minimum air temperature of joydebpur, jamalpur and rajbari during crop growing period in 2018-2019 relationship between grain yield and air temperature there was a negative linear relationship between grain yield (t ha -1 ) of wheat and air temperature of three locations has been shown in fig. 6. at joydebpur, the regression line (y= −2.381x + 53.11, r 2 =0.82) indicated the regression of co-efficient was 2.381 stated that grain yield of wheat decreased at the rate of 2.381 t ha -1 for per unit increase of air temperature (°c). the coefficient of determination (r 2 =0.82) value indicated that air temperature had effect at 82% on grain yield of wheat. similar expression was made by the regression line (y= -2.894x + 63.49, r 2 =0.825) and (y= -1.951x + 42.12, r 2 =0.83) at jamalpur and rajbari, respectively. so, increasing temperature decreases the grain yield of wheat. similar results also have been described by mian et al. (2016).temperature co-efficient (average of three locations) of wheat was estimated at 2.41 t ha -1 (1.95-2.89 t ha -1 ) indicated grain yield reduced @ 2.41 t ha -1 per 1°c increased of air temperature. effect of temperature on the grain yield of wheat was estimated at 81-84%.similar results also have been described by asseng et al. (2010). they surprisingly, observed variations in average growing-season temperatures of ±2 °c in the main wheat growing regions of australia can cause reductions in grain production of up to 50%. 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 m a x im u m a ir t e m p e ra tu re ( 0 c ) wheat growing period joydebpur jamalpur rajbari 0.0 5.0 10.0 15.0 20.0 25.0 7 n o v . 2 1 n o v . 7 d e c. 2 1 d e c. 7 j a n . 2 1 j a n . 7 f e b . 2 1 f e b . 7 m a r. 2 1 m a r. m in im u m a ir t e m p e ra tu re ( 0 c ) wheat growing period joydebpur jamalpur estimation of temperature co-efficient of wheat 79 fig. 6.functional relationship between mean air temperature and grain yield of wheat conclusion the results revealed that physiological maturity as well as crop duration of wheat was reduced by the influence of higher temperature. sowing during 20 november to 30 november would be the optimum sowing date for wheat in relation to air temperature, and early or late sown caused about 2-36% yield reduction over 30 november sowing. temperature co-efficient of wheat was estimated at 2.41 t ha -1 (1.95-2.89 t ha -1 ) indicated grain yield reduced @ 2.41 t ha -1 per 1°c increased of air temperature and effect of temperature on the grain yield of wheat was estimated at 81-84%. references ahmad, n., n.h. shaha, m. habibullah and f.u. khan. 2005. effects of different seed rates, sowing dates and weed control on grain yield of wheat. pakistan j. weed sci. res. 11(3/4): 109-113. ahmed, f., m.s.a. khan and m.h. rahman. 2015. developmental stages, growth indices and yield of hybrid maize cultivars as affected by growing seasons. annual research report 2014-2015, plant physiol. div., bangladesh agril. res. inst. 24p. asseng, s., f. ian and t.c. nail. 2010. the impact of temperature variability on wheat yields. global change biol. 17(2): 997 – 1012. y = -2.381x + 53.11 r² = 0.82 0 1 2 3 4 5 6 20.2 20.4 20.6 20.8 21 21.2 g ra in y ie ld ( t h a -1 ) mean air temperature (°c) a. joydebpur y = -2.8944x + 63.49 r² = 0.84 0 1 2 3 4 5 6 20.2 20.4 20.6 20.8 21 g ra in y ie ld ( t h a -1 ) mean air temperature (°c) b. jamalpur y = -1.951x + 42.12 r² = 0.81 0 1 2 3 4 5 6 19.0 19.2 19.4 19.6 19.8 20.0 20.2 g ra in y ie ld ( t h a -1 ) mean air temperature (°c) c. rajbari 80 begum et al. barc. 2012. frg (fertilizer recommendation guide), bangladesh agricultural research council, bangladesh. farmgate, new airport road, dhaka. p.44 coasta, r., n. pinheiro, a.s. ameida, c. gomes, j. coutinho, j. coco, a. costa, and b. nacas. 2013. effect of sowing date and seeding ratio on bread wheat yield and test weight under mediterranean conditions. emirates j. food and agric. 25: 951-961. gul, h., b. saeed, a.z. khan, u. latif, k. ali, j. rehman and s. rehman. 2012. yield and yield contributing traits of wheat cultivars in relation with planting dates and nitrogen fertilization. arpn j. agril. biol. sci. 7(6): 386395. kamrozzaman m.m, m.a.h. khan, s. ahmed and n. sultana. 2016. growth and yield of wheat at different dates of sowing under charland ecosystem of bangladesh. j. bangladesh agril. univ. 14(2): 147– 154. khan, m.s.a. and m.a. aziz. 2015. impact of sowing date induced temperature and management practices on development events and yield of mustard. bangladesh agron. j. 18(2): 45-52. mian, m.a.k., m.r. islam, j. hossain and m.a. aziz. 2016. grain growth of wheat under prevailing air temperature. bangladesh agron. j. 19(2): 79-85. uddin, r., m.s. islam, m.j. ullah, p.k. hore and s.k. paul. 2015. grain growth and yield of wheat as influenced by variety and sowing date. bangladesh agron. j. 18(2): 97-104. asseng, s., f. ian and t.c. nail. 2010. the impact of temperature variability on wheat yields. global change biol. 17(2): 997 – 1012. bangladesh agron. j. 2018, 21(2): 79-85 fiber yield, physical and biochemical properties of three species of sesbania s. c. chanda1*, m. s. hossain1, m. m. uddin2, m. m. islam3 and a. k. m. golam sarwar1 1 laboratory of plant systematic, department of crop botany, bangladesh agricultural university, mymensingh 2202, bangladesh. 2 textile physics division, bangladesh jute research institute, manik mia avenue, dhaka 1207, bangladesh. 3 agronomy division, bangladesh jute research institute, manik mia avenue, dhaka 1207, bangladesh. *corresponding author, e-mail: sontoshchanda@gmail.com (received: 29 november 2018, accepted: 23 march 2019) keywords: morphological descriptors, fiber luster, fiber strength, proximate analysis, sesbania abstract an experiment was conducted at field laboratory of the department of crop botany, bangladesh agricultural university, mymensingh to compare the fiber yield, physical and biochemical properties of three sesbania species. a total of 38 accessions, 28 from s. bispinosa, 4 from s. cannabina and 5 from s. sesban were used as experimental materials. seeds were sown @ 30 kg ha-1 on 23 april, 2016 following randomized complete block design with three replications. each plot size was 4.0×2.5 m2 maintaining at the spacing of 50 cm row to row and 15 cm plant to plant. plants were harvested at 120 days after sowing and plant height, base diameter, plant fresh weight and dry fiber as well as dry stick weight were measured. the fiber yield was the highest in s. bispinosa (2.18 g plant-1) and the lowest in s. sesban (1.40 g plant-1). fiber luster (%), strength (g tex-1) and crude fiber (%) showed significant differences among these three species. both fiber luster and strength showed the highest value in s. cannabina (53.50% and 51.20 g tex-1, respectively) and the lowest in s. sesban (35.16% and 33.68 g tex-1). crude fiber (%) was also the maximum in s. cannabina (41.41%) and the minimum in s. sesban (25.57%). it may, therefore, be concluded that fiber quality of s. cannabina was superior to other species and could be possible to blend with other natural fiber for industrial purposes. introduction natural fibers have superiority upon artificial fibers in many aspects e.g. environment-friendly, biodegradable, renewable, health benefits, etc. to raise global awareness of the importance of natural fibers, the united nations designated 2009 as the “international year of natural fibers”. bast (/bark) fibers, one of the major sources of natural fibers, are developed in the phloem (inner bark) of dicotyledonous stems like, jute, hemp, flax, ramie, dhaincha, etc. this fiber development is simultaneous with the vegetative growth of the plant (talukder and chanda, 2001). bark fiber yields are ranging between 26-49% of stems weight (maiti, 1980) and fiber length is increased from 0.98 to 1.34 mm with the increase of harvesting age from 2-6 months. the fiber quality depends on its length and coarseness which increase with the increase of plant harvesting time. short and thick fiber doesn’t produce good surface contact and fiber to fiber bonding (ogbonnaya et al., 1997; jahan et al., 2009). biomass and bark weight about:blank 80 chanda et al. may be considered as better selection criteria for yield improvement of the fiber crop. three sesbania species viz. s. bispinosa (jacq.) w. wight [former s. aculeata (wild.) poir.], s. cannabina (retz.) poir. and s. sesban (l.) merr., are commonly known as “dhaincha” in bangladesh (prain, 1903; sarwar et al., 2015). dhaincha is an ideal green manure crop; to lesser extents they are grown for animal feed and fodder, ground cover, providing wood, firewood and other uses in traditional agro-forestry systems. the dhaincha fibers are harsh, coarse and shiny in appearance but lack elasticity (singh and rani, 2014). extracted fiber is suitable for nonwoven fabric and it is used for making fish net and rope, carpets, sackcloth, sailcloth and cordages, paper pulp (jahan et al., 2009; orwa et al., 2009; singh and rani, 2013). in sesbania bispinosa, fiber yield was 9% of whole plant weight and fibers were poor quality and low yield compared to jute (corchorus spp.), kenaf (hibiscus spp.) and urena spp. (maiti, 1980; duke, 1983). this present study, therefore, was undertaken to compare the fiber yield, physical and biochemical properties of three indigenous sesbania species at the mature stage of harvest. materials and methods an experiment was conducted at the field laboratory of crop botany department, bangladesh agricultural university, mymensingh. a randomized complete block design was followed with three replications. the 30 kg ha-1 seeds were sown on 23 april, 2016 on each plot (4.0  2.5 m2) having 8 rows. seeds of 38 accessions from three sesbania species viz. s. bispinosa (28 accessions), s. cannabina (4 accessions) and s. sesban (5 accessions), were used as experimental materials. standard management practices were followed. at 120 days age, dhaincha plants were harvested and plants were taken as a bundle weight around 10 kg. randomly 10 plants were taken from each accession for measurement of plant height, base diameter, plant fresh weight and dry weight of fiber and stick. harvested dhaincha plants were stacked of 3 days for defoliation of leaves. after defoliation of leaves, dhaincha bundles were retted by steeping in water for 15 days. then barks (fiber) were separated from stick and thoroughly washed in water. fibers were sundried on bamboo cross-bar for 5 days. physical properties of fiber were tested at the fiber quality laboratory of bangladesh jute research institute, dhaka following standard procedure. crude protein, crude fiber, biomass, ash and other major chemical properties were measured at the laboratories of department of animal science, bangladesh agricultural university, mymensingh and paper & pulp division, bangladesh council for scientific and industrial research, dhaka following standard procedure (sarkar et al., 2017; kabir et al., 2018). results and discussion the maximum plant height was observed in s. bispinosa (3.00 m) followed by s. cannabina (2.90 m) and the shortest in s. sesban (2.41 m) (table 1). base diameter was ranged from 0.80-1.14 cm in s. bispinosa, 0.74-1.05 cm in s. cannabina and 0.86-0.99 cm in s. sesban. it might be due to differences in the genetic makeup of sesbania species (sarwar et al., 2015). the highest amount of green weight was produced in s. bispinosa (102.50 g plant-1) followed by s. cannabina (98.21 g plant-1) and s. sesban (67 g plant-1). fiber weight varied from 1.11-3.25 g plant-1 in s. bispinosa followed by 1.08-3.20 g plant-1 in s. cannabina and 0.80-2 g plant-1 in s. sesban (table 1). these indicate that there is a positive correlation between fiber yield and plant height, base diameter and fiber yield, physical and biochemical properties 83 biomass yield of dhaincha species. fiber yield might also be controlled by the genetic makeup of the species. duke (1983) reported that fiber yield of s. bispinosa varied from 100-1,000 kg ha-1. on contrary, islam and ali (2017) opined that dry fiber was 5.5% (4.8-6.8%) of whole plant of jute and allied fiber. the heaviest stick was recorded in s. bispinosa (24.83 g plant-1) and the lightest in s. sesban (11.55 g plant-1). though fiber and stick weight together was the largest in s. bispinosa (27.00 ± 4.53 g plant-1), the ratio of green weight to fiber and stick weight was highest in s. sesban (5.17). these indicate that s. sesban has the ability to produce more fiber and stick with relatively smaller amount of green biomass. again the ratio of fiber weight to stick weight ranged from 9.37-17.31 in s. bispinosa, 7.68-12.69 in s. cannabina and 6.6512.26 in s. sesban (table 1). islam and ali (2017) reported that dry ribbon were 10.3% (9.5-11.7%) and dry stick was 15.15% (12.5-16.6%) of whole plant of jute and allied fiber. table 1. fiber yield contributing descriptors of sesbania species descriptor s. bispinosa s. cannabina s. sesban plant height (m) 3.00±0.48 (2.00-4.10) 2.90±0.70 (1.88-3.40) 2.41±0.42 (1.90-2.92) base diameter (cm) 0.96±0.09 (0.80-1.14) 0.90±0.11 (0.74-1.05) 0.93±0.06 (0.86-0.99) green weight (g plant-1) 102.5±16.26 (70.0-135.0) 98.21±12.69 (65.00-131.0) 67.00±9.08 (50.00-84.0) fiber weight (g plant1) 2.18±0.76 (1.11-3.25) 2.14±0.90 (1.08-3.20) 1.40±0.52 (0.80-2.00) stick weight (g plant1) 24.83±4.19 (19.21-30.45) 19.14±5.63 (13.71-24.57) 11.55±2.87 (9.81-13.29) fiber & stick weight 27.01±4.53 (20.32-33.70) 21.28±4.13 (14.79-27.77) 12.95±3.24 (9.71-15.29) green weight : fiber & stick weight 3.80±0.75 (3.44-4.01) 4.62±1.02 (4.39-4.72) 5.17±1.21 (5.09-5.49) fiber weight : stick weight 11.39±4.26 (9.37-17.31) 8.94±3.84 (7.68-12.69) 8.25±3.47 (6.65-12.26) the physical properties of fibers are important characteristics to evaluate for industrial and domestic uses. the fiber luster was varied among sesbania species, and fiber brightness of s. cannabina was better compare to that of s. bispinosa and s, sesban (table 2). the numerical variation was 26.17-62.00% in s. bispinosa, 49.00-65.00% in s. cannabina and 23.80-49.80% in s. sesban. singh and rani (2013) reported that fiber fineness was 37.36% at 30 days after harvest in s. aculeata. fiber diameter was relatively wider (24.61 ± 5.70 µm) in s. sesban and narrower (23.42 ± 2.96 µm) in s. bispinosa (table 2). it may be happened due to the effect of fiber coarseness and thickness of sesbania species. coarse fibers adversely affect the bursting strength, tensile strength and young’s modulus (munawar et al., 2007; kaur and dutt, 2013). the fiber strength was highest in s. cannabina (51.20 ± 4.93 g tex-1.) followed by s. bispinosa (48.56 ± 5.93 g tex-1) and s. sesban (33.68 ± 7.13 g tex-1). the highest strength of fiber may be due to the presence of higher amount of lignin, fat, wax, etc. which act as cementing materials and high tensile strength. the sesbania fibers can be classified as very strong (https://www.cottoninc.com/cotton-production/quality/uscotton-fiber-chart/ratings-of fiber-properties/). linear density of the fiber was decreased due to the loss of hemi-celluloses and it made the cementing capacity of fiber as well as separate out from each other (ray and sarkar, 2000). singh 80 chanda et al. and rani (2013) found that fiber bundle strength of s. aculeata was 15.28 g tex-1 at 30 das and dhaincha fiber was cylindrical in appearance with rough outlines and a canal (lumen) running though the center. however, the cross sectional microscopic view showed that rectangular or square shapes with the serrated edges. table 2. physical properties of sesbania fibers parameter s. bispinosa s. cannabina s. sesban fiber luster (%) 44.93±10.67 (26.17-62.00) 53.50±7.68 (49.00-65.00) 35.16±9.63 (23.80-49.80) fiber diameter (µm) 23.42±2.96 (19.22-31.60) 24.39±3.24 (20.80-28.40) 24.61±5.70 (16.86-31.98) strength (g tex-1) 48.56±5.93 (36.06-60.42) 51.20±4.93 (48.27-56.89) 33.68±7.13 (22.66-57.35) biochemical properties are also considerably different among the sesbania species. the highest biomass (%) was produced in s. bispinosa (91.29 ± 2.39) followed by s. cannabina (90.67 ± 1.14) and s. sesban (90.36 ± 0.71) (table 3). the mineral nutrients content of s. sesban was comparatively better than two other sesbania species. the highest ash (%) was observed in s. sesban (9.03 ± 0.86) and the lowest in s. cannabina (8.00 ± 1.54). it may happen due to genetic variation among the species. crude fiber includes indigestible cellulose, pentosans, lignin, and other components of this type present in the experimental materials. the highest crude fiber (%) found in s. cannabina (41.41 ± 8.06) followed by s. bispinosa (28.95 ± 2.46) and s. sesban (25.57 ± 1.68). a wide variation was observed in the crude protein content (10.72-20.64%) among the s. bispinosa accessions (table 3); therefore, there is a possibility to select accessions/genotypes with high crude protein content as animal feed and fodder. table 3. biochemical properties of sesbania species composition s. bispinosa s. cannabina s. sesban biomass (%) 91.29±2.39 (88.49-96.53) 90.67±1.14 (89.48-92.04) 90.36±0.71 (89.46-91.04) ash (%) 8.50±2.28 (4.00-12.98) 8.00±1.54 (6.98-10.01) 9.03±0.86 (8.00-10.00) crude fiber (%) 28.95±2.46 (25.05-33.25) 41.41±8.06 (31.00-47.06) 25.57±1.68 (23.23-26.71) crude protein (%) 16.38±2.46 (10.72-20.64) 16.31±1.77 (14.01-17.78) 18.22±0.94 (17.10-19.40) klason-lignin (%) 23.10±1.73 (20.91-26.87) 23.05±0.20 (22.91-23.19) 21.97±0.10 (21.87-22.07) holo-cellulose (%) 70.19±3.20 (66.30-74.55) 70.79±6.63 (66.10-75.47) 70.28±0.80 (69.77-71.20) α-cellulose (%) 40.97±1.07 (39.50-42.27) 40.31±0.81 (39.74-40.88) 41.22±1.37 (40.42-42.80) a little difference was found in the klason-lignin, holo-cellulose and α -cellulose content in the three sesbania species studied (table 3). duke (1983) observed that 9.76% pentosan, 16.3% lignin, 85.2% holo-cellulose (63.6% α-cellulose) were present in s. bispinosa. panzhi (1988) found that the lignin amount is 14.06%, pentosan 14.45% and holo-cellulose 73.61% in sesbania species and also added that lignin and pentosan is lower in sesbania than that of in reed and cellules are similar. differences between holo-cellulose and α-cellulose represent hemicelluloses which are greatly responsible for giving overall strength of fiber fiber yield, physical and biochemical properties 83 (rahman et al., 2016). the cellulose content of the fiber was increased while hemicelluloses and lignin content was decreased due to their removal from the fiber (brindha et al., 2012). chemical composition of fiber varied due to a great extent between within the species which is affected growth condition and fiber processing method (mohanty et al., 2000). the fibers have composite such as structure and consists of stiff crystalline cellulosic micro fibrils as reinforcement held together through lignin, hemicelluloses, waxes and some water soluble extractives (fengel and wegener, 1989). rowell (2005) reported that wood and plant fiber of cellulose act as reinforcement, hemicelluloses and pectin as bonding, lignin for stiffness and wax for use as coating. the rich content of cellulose leads to improve the mechanical properties, however, the low hemi-cellulose content leads to reduce the moisture absorption capacity and in turn increase the thermal stability of the fiber (raja et al., 2016). the presence of lignin content acts as a bonding agent between the cell wall structures to improve the rigidity and strength of the fiber. tanmoy et al. (2014) reported that jute plants hold three major categories of chemical compounds like cellulose (58-63%), hemi-cellulose (20-24%) and lignin (12-15%), and some other small quantities fats, pectin, aqueous extract, etc. raja et al. (2016) reported that s. rostrata fibers showed cellulose content of 64.36%, hemicelluloses 11.25%, lignin 17.19% and ash 1.45%. conclusion yield contributing parameters like plant height, base diameter, green weight, fiber weight, stick weight significantly differ among the three sesbania species. although the differences of physical and biochemical properties of three sesbania species were very close , however, the properties of fiber luster (%), strength (g tex-1) and crude fiber (%) had the highest differences among the three species. it may conclude that the fiber quality of s. cannabina was the superior compare to s. bispinosa and s. sesban. sesbania fibers could be used, like as jute fiber, for blending with other natural fibers which can reduce the cost of an expensive fiber. acknowledgements we acknowledge the financial support of the ministry of science and technology, government of the people’s republic of bangladesh. references brindha, d., s. vinodhini, k. alarmelumangai and n. s. malathy. 2012. physicochemical properties of fibers from banana varieties after scouring. indian j. fund. appl. life sci. 2: 217 -221. duke, j. a. 1983. handbook of energy crops (unpub.). purdue univ. cen. new crops plant prod. (https://hort.purdue.edu/newcrop/duke_energy/sesbania_bispinosa.html) fengel, d and g. wegener. 1989. wood—chemistry, ultrastructure, reactions. 2nd ed., walter de gruyter, berlin. islam, m. m and m. s. ali. 2017. economic importance of jute in bangladesh: production, research achievements and diversification. int. j. econ. theo. appl. 4: 45-57. 80 chanda et al. jahan, m. s., r. sabina, b. tasmin, d. a. n. chowdhury, a. noori and a. almaruf. 2009. effect of harvesting age on the chemical and morphological properties of dhaincha (sesbania species) and its pulpbility and bleach ability. bioresour. 4: 471-481. kabir, a. k. m. a., m. moniruzzaman, z. gulshan, a. b. m. m. rahman and a. k. m. golam sarwar. 2018. biomass yield, chemical content and in vitro gas production of different dhaincha (sesbania spp.) accessions from bangladesh. indian j. anim. nutri. 35: 397-402. kaur, h and d. dutt. 2013. anatomical, morphological and chemical characterization of lignocelluloses by-products of lemon and sofia grasses obtained after recuperation of essential oils by steam distillation. cellulose chem. technol. 47: 83-94. maiti, r. k. 1980. plant fibers. b. singh and m.p. singh, dehra dun, india. pp: 71-81. mohanty, a. k., m. misra and g. hinrichsen. 2000. biofibres, biodegradable polymers and biocomposites: an overview. macromol. mater. eng. 276-277: 1-24. munawar, s. s., k. umemura and s. kawai. 2007. characterization of the morphological, physiological and mechanical properties of seven nonwood plant fiber bundles. j. wood sci. 53: 108-113. ogbonnaya, c. i., h. roy-macauley, m. c. nwalozie and d. j. m. annerose. 1997. physical and histochemical properties of kenaf (hibiscus cannabinus l.) grown under water deficit on a sandy soil. indus. crops prod. 7: 9-18. orwa, c., a. mutua, r. kindt, r. jamnadass and s. anthony. 2009. agroforestree database: a tree reference and selection guide version 4.0. world agroforestry centre, kenya. (http://www.worldagroforestry.org/output/aftreedatabase). prain, d. 1903. bengal plants. indian rep., b. singh and m.p. singh, dehra dun, india. pp: 402-404. rahman, m. m., s. siddiqua, f. akter, m. s. jahan and m. a. quaiyyum. 2016. variation of morphological and chemical properties of three varieties of jute stick. bangladesh j. sci. indus. res. 51: 307-312. raja, k, p. senthilkumar, g. nallakumarasamy and t. natarajan. 2016. characterization of natural fiber extracted from sesbania rostrata: an alternative potential for synthetic fibers. j. adv. chem. 12: 4930-4937. ray, d. and b. k. sarkar. 2000. characterization of alkali treated jute fiber for physical and mechanical properties. j. appl. polym. sci. 80: 1013-1020. rowell, r. m. 2005. handbook of wood chemistry and wood composites. crc press, london. sarker, m., s. sutradhar, a. k. m. golam sarwar, m. n. uddin, s. c. chanda and m. s. jahan. 2017. variation of chemical characteristics and pulpability of dhaincha (sesbania bispinosa) on location. j. bioresour. bioprod. 2: 24-29. sarwar, a. k. m. golam, a. islam and s. jahan. 2015. characterization of dhaincha accessions based on morphological descriptors and biomass production. j. bangladesh agril. univ. 13: 55-60. singh, n. and a. rani. 2013. extraction and processing of fiber from sesbania aculeata (dhaincha) for preparation of needle punched nonwoven fabric. natl. acad. sci. lett. 36: 489-492. fiber yield, physical and biochemical properties 83 singh, n. and a. rani. 2014. needle punched non woven of sesbania aculeata (dhaincha) fiber. int. j. text. fash. tech. 4: 7-12. talukder, f. a. h. and s. c. chanda. 2001. a glimpse of fiber crop of jute. saic newsletter. 11: 8. tanmoy, a. m., m. a. alum, m. s. islam, t. farzana and h. khan. 2014. jute (corchorus olitorius var. o-72) stem lignin: variation in content with age. bangladesh j bot. 43: 309-314. bangladesh agron. j. 2019, 22 (1): 27-37 performance of hybrid rice (bio-453) in variation of spacing and number of seedling per hill d. chowdhury1, m. biswas2, m.n.h. miah1, p. mandal1 and m.s. hossain1* 1department of agronomy and haor agriculture, sylhet agricultural university, sylhet, bangladesh 2department of agro product processing technology, jessore university of science and technology, jessore, bangladesh *corresponding e-mail: sazzadmh.aha@sau.ac.bd (received: 25 march 2019, accepted: 30 may 2019) keywords: hybrid rice, seedling hill-1, spacing, growth and yield abstract hybrid rice production can ensure to get more yields per unit land. the research work was carried out to evaluate the effect of number of seedling hill-1 and spacing on the growth and yield of hybrid rice line bio-453. the experiment was laid out in a split-plot design with 3 replications at the field of agronomy and haor agriculture department of sylhet agricultural university, under the aez 20 in kharif-ii (aman) season of 2013. number of seedling hill-1 was assigned in the main plot and plant spacing in the sub-plot. two levels of seedling hill-1 viz. ns1 (1 seedling hill-1) and ns2 (2 seedlings hill -1) and five levels of plant spacing viz. sp1 (15 cm x 15 cm), sp2 (15 cm x 20 cm) and sp3 (20 cm x 20 cm), sp4 (20 cm x 25 cm) and sp5 (20 cm x 30 cm) were the treatments. number of seedling hill-1 and plant spacing showed significant effect in yield and yield contributing parameters except days to maturity, plant height, 1000-grain weight, total tillers hill-1, number of effective tillers hill-1, harvest index and grains panicle-1. maximum grain yield (9.43 t ha-1), straw yield (16.27 t ha-1) and biological yield (25.70 t ha-1) were obtained from 1 seedling hill-1 (ns1) with the closest spacing 15 cm x 15 cm therefore, one seedling hill-1 with 15 cm distance for plant and row to row distance could ensure maximum yield of hybrid rice line bio-453. introduction in bangladesh soil and climatic conditions are favorable for rice cultivation and it is extensively cultivated throughout the year in three seasons namely aus, aman and boro which covers 80% of the total cultivable area of the country (ais, 2011). in respect of production, it ranks 4th place among the rice producing countries of the world (fao, 2018). however, the average rice yield in bangladesh is lower than the other rice growing countries like china, japan, korea (fao, 2009). besides the cultivable land is converting into non cultivable land around @1% every year (quasem, 2011). in this situation hybrid rice production can be a good option to contribute to increase rice yield about 1520% over the modern varieties (julfiquar et al., 2001). bangladesh rice research institute (brri) already released six hybrid rice varieties in boro and t. aman, however only two rice hybrids released for t. aman season. but recently farmers are reluctant to cultivate more hybrid rice because of its higher requirements of fertilizer, irrigation etc. than the conventional rice either local or hyv which ultimately increase the cost of production. sylhet is situated in the north-east portion of bangladesh which is comparatively a higher rainfall area. t. aman occupying a major percentage in the cropping patterns of this area (dae, 2012). about:blank 38 chowdhury et al. number of seedling hill-1 plays an important role to enable the plant to grow properly both in its aerial and underground parts by utilizing maximum radiant energy, nutrient, space and water and also could reduce seedlings cost of farmers. proper plant spacing responsible for the plant density that can minimize the seed requirement without sacrificing productivity of hybrid rice cultivation. profuse tillering of the hybrid rice may compensate the yield due to reduction in plant population (srinivasulu et al., 1999). the growth, development, yield and yield components of rice are greatly influenced by plant spacing through proper utilization of solar radiation, soil and applied nutrients (akter, 2004). when the plant densities and seedling hill-1 exceed optimum level, competition among them for light and nutrients become severe. consequently, the growth rate slows down and the grain yield decreases. wider spacing can produce more tillers when soil, water and nutrients are sufficiently available that produce higher yield. keeping in view, a new advanced hybrid rice line bio-453 under two levels of seedling hill-1 and five levels of plant spacing were undertaken to know the effect of number of seedling hill-1 and spacing on yield and yield attributes. materials and methods the study was carried out at the field of agronomy and haor agriculture department of sylhet agricultural university, in kharif-ii (aman) season during july to november 2013.the experiment was laid out in a split-plot design with three replications where main plot includes number of seedling hill-1 such as: 1) seedling hill-1 (ns1) and 2) seedlings hill -1 (ns2) and in sub-plot assigned plant spacing such as:i) 15 cm × 15 cm (sp1), ii) 15 cm x 20 cm (sp2), iii) 20 cm x 20 cm (sp3), iv) 20 cm x 25 cm (sp4) and v) 20 cm x 30 cm (sp5).the size of the unit plot was 4.8 m2 hybrid rice line bio-453 was collected from bioseed research india pvt. ltd. sprouted seeds were sown in the well-prepared wet nursery bed. thirty-four days old seedling was transplanted at a depth of 3-5 cm. during transplanting 5-7 cm water depth was maintained in each plot. different intercultural operations were done for ensuring the normal growth of the crop. the experimental field was ploughed leveled well and well decompose cow dung was applied @5 t ha-1. dolochun lime was applied @0.75 t ha-1 to increase soil ph. the experimental area was fertilized with 68.72 kg, 10.98 kg, 41.81 kg, 14.04 kg, 1.1 kg of n, p, k, s and zn per hectare, respectively (brri, 2013). one-third of urea and the entire tsp, mop, gypsum and zinc oxide were incorporated into the soil during final land preparation. remaining two-thirds of urea was top dressed at 40 days after transplanting (dat) and at 55 dat. data were collected on yield and yield attributes. the collected data were tabulated and analyzed using computer package program r. mean differences were adjudged by the least significant difference (lsd) test at 5% level of significance. results and discussion plant height effect of number of seedling hill-1 (ns) no significant differences were observed on plant height at different dat in variation of number ofseedlingshill-1. effect of spacing (sp) plant spacing exerted significant effect on plant height at different dat (fig. 1). although the maximum plant height (135.50 cm) was recorded atsp2 which was similar to sp1 (135.12 cm) and spacing sp4 (130.58 cm). the minimum plant height (122.74 cm) was obtained from the widest spacing sp5. performance of hybrid rice 37 fig. 1. effect of spacing (sp) on plant height at different days after transplanting (dat) (lsd = 3.67, 4.08, 5.24, 4.37, 6.18 and 7.02 at 54, 69, 84, 99, 114 and 129 dat, respectively. interaction effect of number of seedling hill-1 and spacing plant height at different dat was significantly influenced by the interaction between number of seedling hill-1 and spacing (fig. 2). the maximum plant (143.68 cm) was recorded from ns1×sp1 that was statistically closer to the plant height of ns1×sp2 and ns2×sp4 (140.90 cm and 140.18 cm). the shortest plant height was observed in treatment of ns1×sp5 that was statistically similar to ns1×sp4 and ns2×sp3.the result was similar with the findings of ninad et al. (2017), shrirame et al. (2000) and shah et al. (1991). fig. 2. interaction effect of number of seedling hill-1 and spacing on plant height at different dat (lsd = 5.19, 5.77, 7.41, 6.19, 8.74 and 9.92 at 54, 69, 84, 99, 114 and 129 dat, respectively). number of tiller hill-1 at every 15-day intervals effect of number of seedlings hill-1 38 chowdhury et al. number of seedling hill-1 had significant effect on number of tiller hill-1at earlier stage but no significant effect on later stage (fig. 3). the higher number of tiller hill-1 (8.22) was obtained from ns2at 84 dat and the lower number of tiller hill-1 (5.81) was obtained from ns1 at 54 dat. fig. 3. effect of number of seedling hill-1 (ns) on number of tiller hill-1 at different dat (lsd = 0.66, 0.13, 0.98, 1.90, 2.13 and 1.97 at 54, 69, 84, 99, 114 and 129 dat, respectively). effect of spacing there was significant effect of plant spacing on number of tiller hill -1 at different dat except 54 dat (fig. 4). the maximum number of tiller hill1(11.87) was obtained from the spacing of sp5 at 99 dat. the minimum number (7.43) was found from the spacing of sp1at 54 dat which was statistically similar to the number of tiller hill-1 7.46 and 8.23 with the spacing of sp2 and sp3, respectively. fig. 4. effect of spacing on number of tiller hill-1 at different dat (lsd = 0.84, 1.37, 1.17, 1.20, 1.60 and 1.35 at 54, 69, 84, 99, 114 and 129 dat, respectively). interaction effect of number of seedling hill-1 and spacing performance of hybrid rice 37 number of tiller hill-1 at 114 dat was significantly influenced by interaction between number of seedling hill-1 and spacing (fig. 5). the highest number of tiller hill-1 (13.27) was found from ns2×sp5 at 99 dat. the lowest number (5.13) was obtained from ns1×sp1 at 54 dat. fig.5 interaction effect of number of seedling hill-1 and spacing on number of tiller hill-1at different dat (lsd = 1.19, 1.93, 1.66, 1.70, 2.26 and 1.91 at 54, 69, 84, 99, 114 and 129 dat, respectively). phenology, yield components and yield effect of number of seedling hill-1 number of seedling hill-1 had no significant effect on days to 50% panicle initiation, days to maturity, plant height at harvest (table 1). shrirame et al. (2000) observed similar results. gupta (1996) also found that transplanting of one seedling hill-1 significantly increased plant height. this observation was also supported by nayak et al. (2003) who stated that plant height recorded significantly more with 1 seedling hill-1 than the 2 seedlings hill-1. similar result was found in case of non-effective tiller hill-1, panicle length, grains panicle-1, weight of 1000-grain, grain yield, straw yield, biological yield. rajarathinam (1999) similarly stated that the straw yield of hybrid rice was not changed significantly due to planting of single or double seedlings hill-1. number of total tiller hill-1 and effective tiller hill-1 were significantly influenced by number of seedling hill-1 (table 1). the higher number of total tiller hill-1 (12.13) was found in 2 seedlings hill-1 (ns2) and the lower one (10.91) with 1 seedling hill-1 (ns1). alam (2006) reported similarly that highest number of effective tillers was obtained from 2 seedlings hill-1. number of seedling hill-1 had no significant effect on harvest index (table 1). table 1. phenology and yield components of hybrid rice line bio-453 as influenced by number of seedlings hill-1 38 chowdhury et al. no. of seedling hill-1 (ns) days to 50% flowering days to maturity plant height (cm) total tiller hill-1 (no.) effective tiller hill1 (no.) noneffective tiller hill1 (no.) panicle length (cm) ns1 105 137 131.69 10.91 b 8.55 b 2.36 24.53 ns2 105 130 131.41 12.13 a 9.35 a 2.77 24.35 lsd (0.05) ns ns ns 1.17 0.84 ns ns cont’d no. of seedling hill1 grain panicle-1 (no.) 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) ns1 81.24 27.15 8.38 13.17 21. 72 38.69 ns2 80.15 26.77 8.02 13.06 21.08 38.08 lsd (0.05) ns ns ns ns ns ns note: ns1 = 1 seedling hill -1; ns2 = 2 seedlings hill -1; ns = non-significant; * indicate 5% level of significance. effect of spacing days to maturity, plant height, panicle length, grain panicle-1, 1000 grain weight and harvest index was not significantly affected by plant spacing (table 2). days to 50% flowering plant spacing had significant effect on days to 50% flowering (table 2). maximum days (107) required for 50% flowering at the spacing of sp4 and sp5 whereas statistically minimum days (103) required at the spacing of sp1, sp2 and sp3. total tiller hill-1 plant spacing had significant effect on number of total tiller hill-1 (table 2). the maximum number of total tiller hill-1 (13.61) was found in the wider sp5 which was statistically similar to spacing sp4. the lowest number (9.50) was observed in the closest spacing sp1. the plants grown in sp5 possibly experienced more light, space, air and nutrient facilities which stimulated positively towards tiller formation than the closer spacing. effective tillers hill-1 the number of effective tillers hill-1 was significantly influenced by spacing (table 2). the maximum number of effective tillers hill-1 (10.88) was obtained from sp5 which was statistically similar to thesp4 (10.61). the lowest one (7.43) was obtained from sp2 which was statistically similar with sp2 and sp3 (7.61 and 8.10, respectively). the result showed that sp5 had the greatest opportunity to produce more number of effective tillers hill-1 because it gets enough space, nutrients, light and air which played great role in producing more effective tillers hill-1. baloch et al. (2002) reported wider spaced plant produced more effective tillers in rice than closer one. non-effective tillers hill-1 the number of non-effective tillers hill-1 was significantly influenced by spacing (table 2). the highest number of non-effective tillers hill-1 (2.94) was found in sp3 which performance of hybrid rice 37 was statistically closer to the number of non-effective tillers hill-1of 2.72 and 2.82 with the spacing sp2 and sp5, respectively. the lowest number (2.04) was found in the spacing sp1 which was statistically similar to the sp4 (2.39). grain yield plant spacing had significant effect on grain yield (table 2). the maximum grain yield (8.93 t ha-1) was obtained from sp1 which was statistically similar with sp2 and sp3 (8.63 and 8.45 t ha -1). the result was similar to ninad et al. (2017) and chandra et al. (1997) who recorded that the closer spacing 15 cm x 15 cm gave 10-12% higher yield than the other spacing. the lowest yield (7.28 tha-1) was obtained from the spacing 20 cm x 30 cm (sp5) which was also statistically similar to the grain yield of 7.66 t ha-1 obtained from the spacing 20 cm x 25 cm (sp4). the results revealed that closest spacing gives higher yield performance whereas wider spacing gave lower yield. this might be due to the fact that closest spacing had higher plant population (i.e. hill unit-1 area) than the corresponding wider spacing in spite of higher number of effective tillers hill-1, filled grains panicle-1 and 1000-grain weight. the result corroborates with the findings of other few research findings that closer spacing had higher grain yield than the other spacing (azad et al., 1995; patel, 1999; obulamma et al., 2002). straw yield straw yield was significantly influenced by spacing (table 2). the maximum straw yield (14.47 t ha-1) was produced from the closest spacing 15 cm x 15 cm (sp1) which was statistically closer to the straw yield (14.17 t ha -1) obtained from the spacing 15 cm x 20 cm (sp2). the moderate straw yield (13.02 t ha -1) was recorded from the spacing 20 cm x 20 cm (sp3) which was statistically similar to the straw yield (12.57 t ha-1) obtained from the spacing 20 cm x 25 cm (sp4). the minimum yield (11.35 t ha -1) was produced from the widest spacing of 20 cm x 30 cm (sp5). the results showed that straw yield increased with closer spacing and decreased with wider spacing. biological yield plant spacing exerted significant effect on biological yield (table 2). the highest biological yield (23.40 t ha-1) was obtained from the closest spacing sp1 which was statistically similar to the biological yield sp2 (22.85 t ha -1). the lowest biological yield (18.63 t ha-1) was obtained from the widest spacing sp5. the result showed that closer spacing provided the highest biological yield. it might be due to the fact that closer spacing had more population densities which added more biomass that was accumulated before flowering and translocated to the grains during grain filling. table 2. phenology and yield components of hybrid rice line bio-453 by spacing 38 chowdhury et al. plant spacing (sp) days to 50% flowering days to maturity plant height (cm) total tiller hill-1 (no.) effective tiller hill-1 (no.) noneffective tiller hill-1 (no.) panicle length (cm) sp1 103 b 137 133.78 9.50 d 7.44 c 2.04 c 24.76 sp2 104b 137 134.77 10.45 c 7.61 c 2.82 ab 24.53 sp3 104 b 137 130.05 11.05 c 8.22 c 2.94 a 24.21 sp4 107 a 137 131.55 12.50 b 9.72 b 2.39 bc 24.47 sp5 107 a 137.67 127.61 14.11 a 11.78 a 2.72 ab 24.22 (continued) plant spacing grain panicle-1 (no.) 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) sp1 81.55 26.93 8.93 a 14.47 a 23.40 a 38.33 sp2 79.61 26.03 8.68 a 14.17 ab 22.85 a 37.93 sp3 79.16 26.93 8.45 a 12.57 c 21.01 b 40.20 sp4 83.66 27.68 7.67 b 13.39 bc 21.06 b 36.35 sp5 79.50 27.21 7.28 b 11.35 d 18.63 c 39.13 note: sp1 = 15 cm x 15 cm; sp2 = 15 cm x 20 cm; sp3 = 20 cm x 20 cm; sp4 = 20 cm x 25 cm; sp5 = 20 cm x 30 cm interaction effect of number of seedling hill-1 and spacing days to 50% flowering days to 50% flowering, days to maturity, plant height, total tillers hill-1, panicle length, grains panicle-1, 1000-grain weight and harvest index was not significantly influenced by the interaction between number of seedling hill-1 and spacing (table 3). effective tillers hill-1 number of effective tillers hill-1 was significantly affected by interaction between number of seedling hill-1 and spacing (table 3). the highest number of effective tillers hill-1 (12.22) from 2 seedlings hill-1 (ns2) with 20 cm x 30 cm spacing (sp5) which was statistically similar to1 seedling hill-1 (ns1) with 20 cm x 30 cm spacing (sp5). the number of effective tillers hill -1 of 7.63 and 7.88 recorded from 2 seedlings hill-1 (ns2) with the spacing 15 cm x 15 cm (sp1) and 15 cm x 20 cm (sp2), respectively was statistically similar. the lowest number (7.22) was recorded from 1 seedling hill-1 (ns1) with the spacing of 15 cm x 15 cm (sp1) that was statistically similar to 1 seedling hill-1 (ns1) with 15 cm× x 20 cm (sp2) and 20 cm x 20 cm (sp3) spacing, respectively. non-effective tillers hill-1 performance of hybrid rice 37 there was significant effect by the interaction between number of seedling hill-1 and spacing on number of non-effective tillers hill-1 (table 3). the maximum number of non-effective tillers hill-1 (3.55) was found in ns2× sp2which was significantly closer to ns1sp3 and ns1sp4, respectively. the minimum number (1.66) was obtained from ns1sp1 which was as at par to (ns1sp2) and (ns1sp5), respectively. grain yield significant influence by interaction between number of seedling hill -1 and spacing on grain yield was found (table 3). maximum grain yield (9.43 t ha -1) was obtained from ns1×sp1 which was statistically similar to ns1sp2 and ns1sp3 (9.26 and 8.86 t ha -1 respectively). the result corroborates with the findings of (strivastava and tripathi, 1998) that 1 seedling hill-1 in combination with the spacing 15 cm x 15 cm (sp1) produced the highest grain yield in hybrid rice. minimum grain yield (7.0 t ha -1) was obtained from (ns1sp5) which was significantly similar to the grain yield (7.36 t ha-1) from ns1sp4. the results revealed that the combination of single seedling hill -1 with closer spacing had higher yield performance whereas the combination of single seedling hill-1 with wider spacing had lower yield performance. straw yield the interaction between number of seedling hill -1 and spacing exerted significant effect on straw yield (table 3). the maximum straw yield (16.27 t ha-1) was produced from ns1× sp1 that was statistically similar to the straw yield (14.83 t ha-1) at ns1sp2. the lowest straw yield (10.43 t ha -1) was produced from ns1×sp5 which was similar to ns1× sp3 (11.77 t ha -1). the straw yield (12.53 t ha-1) produced at 1 seedling hill-1 (ns1) with the spacing of 20 cm x 25 cm (sp4) statistically similar to the straw yield of 12.67 t ha 1, 12.60 t ha-1 and 12.27 t ha-1 recorded from 2 seedlings hill-1 (ns2) with the spacing of 15 cm x 15 cm (sp1), 20 cm x 25 cm (sp4) and 20 cm x 30 cm (sp5), respectively. biological yield biological yield was significantly influenced by seedling hill -1 and spacing (table 3). maximum biological yield (25.70 t ha -1) was found in (ns1×sp1) which was statistically similar with ns1×sp2 (24.10 t ha -1). minimum biological yield (17.43 t ha-1) recorded from 1 seedling hill-1 (ns1) with 20 cm x 30 cm spacing (sp5), which was significantly different from the others. table 3. phenology and yield components of hybrid rice line bio-453 by interaction effect of number of seedling hill-1 (ns) and spacing (sp) interaction of nssp days to 50% flowering days to maturity plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) non-effective tillers hill-1 (no.) panicle length (cm) ns1 x sp1 103 137 141.00 8.89 7.22 1.66 d 25.04 ns1 x sp2 106 138 140.88 9.44 7.36 2.05 cd 24.77 ns1 x sp3 105 137 132.78 10.33 7.23 3.12 ab 24.05 ns1 x sp4 106 134 123.11 12.44 9.55 2.88 ab 24.75 ns1 x sp5 106 137 120.67 13.44 11.33 2.10 cd 24.02 ns2 x sp1 104 136 126.56 10.11 7.63 2.44 bcd 24.48 ns2 x sp2 103 136 128.65 11.44 7.88 3.55 a 24.27 ns2 x sp3 102 137 127.33 11.78 9.11 2.66 bc 24.36 ns2 x sp4 107 138 139.98 12.56 9.89 2.67 bc 24.18 ns2 x sp5 108.0 138 134.56 14.78 12.22 2.56 bc 24.43 (continued) 38 chowdhury et al. interaction of nssp grain panicle-1 (no.) 1000-grain weight (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) ns1 x sp1 84.22 27.43 9.43 a 16.27 a 25.70 a 36.66 ns1 x sp2 83.78 26.89 9.26 ab 14.83 ab 24.10 ab 38.33 ns1 x sp3 76.77 26.60 8.86 abc 12.53 de 21.40 cd 41.43 ns1 x sp4 80.11 26.83 7.36 ef 11.77 ef 19.96 d 36.90 ns1 x sp5 77.28 26.90 7.00 f 10.43 f 17.43 e 40.13 ns2 x sp1 83.10 27.93 8.43 bcd 12.67 cde 21.10 cd 40.00 ns2 x sp2 75.44 26.36 8.10 cde 13.50 bcd 21.60 cd 37.53 ns2 x sp3 81.55 27.27 8.03 cde 12.60 de 20.63 cd 38.96 ns2 x sp4 82.99 27.03 7.96 cdef 14.27 bc 22.23 bc 35.80 ns2 x sp5 80.72 27.20 7.56 def 12.27 de 19.83 d 38.13 note: ns= number of seedling; sp= spacing. conclusion from the experimental findings it is clear that hybrid rice line bio-453 planted with 1 seedling hill-1 along with 15 cm x 15 cm spacing produced maximum grain yield (9.43 t ha-1) while combination of 2 seedlings hill-1 along with 20 cm x 30 cm spacing contributed lower yield (7.56 t ha-1). consequently, hybrid rice line bio-453 with the combination of 1 seedling hill-1 with 15 cm x 15 cm spacing to be the best possible combination for achieving higher grain yield per unit area. references ais. 2011. krishi dairy, agril. inform. ser. kamarbari, farmgate, dhaka, bangladesh. akter, f.m.f. 2004. effect of plant spacing and nitrogen level on the performance of transplant aman rice. ms thesis, dept. of agron., bangladesh agril. univ., mymensingh, bangladesh. alam, f. 2006. effect of spacing, number of seedlings hill-1 and fertilizer management on the performance of boro rice cv. brri dhan29. thesis, dept. agron., bangladesh agril. univ., mymensingh, bangladesh. azad, a.k., m.a. gaffer, s.c. samanta, m.a. kashem and m.t. islam. 1995. response of brio rice to different levels of nitrogen and spacings. bangladesh j. sci. indus. res. 30: 31–38. baloch, a.w., a.m. soomro, m.a. javed and m. ahmed. 2002. optimum plant density for high yield in rice. asian j. plant sci. 1: 25-27. brri. 2013. adhunik dhaner chash, 17th edition. gazipur. chandra, d., s.b. lodh, k.m. sahoo and b.b. nanda. 1997. effect of date of planting and spacing on grain yield and quality of scented rice (oryza sativa) varieties in wet season in coastal orissa. indian j. agric. sci. 67: 93–97. dae. 2012. report on cropping pattern of sylhet. sylhet, bangladesh. fao. 2009. production yearbook. food and agric. organiz. united nations, rome, italy. fao. 2018. faostat database of agriculture (crops). food and agric. organiz. performance of hybrid rice 37 united nations, rome, italy. gupta, s.k. 1996. effect of planting seedling and nitrogen on yield of rice (oryza sativa). indian j. agron. 41: 581–583. julfiquar, a.w., s.s. virmani, m.m. haque, m.a. mazid and m.m. kamal. 2001. hybrid rice in bangladesh: opportunities and challenges. international rice research conference, los baños, laguna (philippines), 31 mar-3 apr 2000 irri, philippines. nayak, b.c., b.b. dalei and b.k. choudhury. 2003. response of hybrid rice (oryza sativa) to date of planting, spacing and seedling rate during wet season. indian j. agron. 48: 172–174. ninad, t.a., m.m. bahadur, m.a. hasan, m.m. alam and m.s. rana. 2017. effect of spacing and seedling per hill on the performance of aus rice var. brri dhan48. bangladesh agron. j. 20: 17-26. obulamma, u., r. reddeppa and r. reddy. 2002. effect of spacing and seedling number on growth and yield of hybrid rice. j. res. angrau. 30: 76–78. patel, j.r. 1999. response of rice (oryza sativa) to time of transplanting, spacing and age of seedings. indian j. agron. (india). 44: 344-346. quasem, m.a. 2011. conversion of agricultural land to non-agricultural uses in bangladesh: extent and determinants. the bangladesh development studies.pp.59–85. rajarathinam, p. 1999. optimum plant population, seedling density and n levels for medium duration hybrid rice (oryza sativa). indian j. agric. sci. 69: 583–585. shah, m.h., m.k. khushu, b.a. khanday and a.s. bali. 1991. effect of spacing and seedlings per hill on transplanted rice under late sown condition. indian j. agron. 36: 274-275. shrirame, m.d., h.j. rajgire and a.h. rajgire. 2000. effect of spacing and seedling number per hill on growth attributes and yield of rice hybrids under lowland condition. j. soil. crop. 10: 109–113. srinivasulu, k., r. veeraraghavaiah and k. madhavi. 1999. growth performance of rice hybrids under different methods and densities of planting. crop res. 18: 1–7. strivastava, o.k. and r.s. tripathi. 1998. response of hybrid and composite rice to number of seedling and planting geometry. ann. agric. res. newsl. pp.235-236. microsoft word 11 bangladesh agron. j. 2017, 20(2): 97-105 eeeeffect of drought stress on growthffect of drought stress on growthffect of drought stress on growthffect of drought stress on growth andandandand yieldyieldyieldyield of wheat genotypesof wheat genotypesof wheat genotypesof wheat genotypes afrose jahanafrose jahanafrose jahanafrose jahan1111**** and f. and f. and f. and f. ahmedahmedahmedahmed2222 1department of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2plant physiology division, bari, gazipur-1701, bangladesh *corresponding author, e-mail: jahansau@yahoo.com (receivedreceivedreceivedreceived: 10 november 2017, accepted:accepted:accepted:accepted: 23 december 2017) key words:key words:key words:key words: wheat, genotype, drought abstractabstractabstractabstract a pot experiment on screening of wheat genotypes against drought stress was conducted at the research field of sher-e-bangla agricultural university in earthen pots during rabi season of 2013-2014. fifteen (15) wheat genotypes were evaluated under drought (stress was imposed by withdrawing irrigation after emergence) and well irrigated (control) condition. exposure of plants to drought led to remarkable reduction in yield contributing characters which ultimate caused in reduced yield in all the genotypes. however, genotypes showed remarkable variability in yield reduction due to drought. the highest relative yield was observed in genotype satyn-25 followed by satyn-2, bari gom-26 and bari gom-28. however, yield reduction was less in satyn-25 (about 20%) followed by bari gom-26 (21%) and satyn-2 (25%). besides yield performance of the genotypes, some drought tolerance indices like geometric mean productivity (gmp), stress tolerance index (sti), yield stability index (ysi) and stress susceptible index (ssi) were used to select the desirable genotypes. among the genotypes, bari gom-26, bari gom-28 and satyn-25 gave better yield with higher sti, gmp and ysi with lower ssi indicating that these genotypes would be suitable for growing under drought prone areas. introductionintroductionintroductionintroduction drought stress is a major abiotic factor that limits agricultural production (jaleel et al., 2009; golbashy et al., 2010), more importantly in the rain-fed areas of the world (nikus et al., 2004). drought is the most severe stress and the main cause of significant losses in growth, productivity of crop plants and finally their yields (ludlow and muchow, 1990). drought affects morpho-physiological, bio-chemical and molecular processes in plants resulting in growth inhibition, stomata closure with consecutive reduction of photosynthesis, transpiration, decrease in chlorophyll content and inhibition of photosynthesis and protein changes (lawlor and cornic, 2002; zhu, 2002) to cope with osmotic changes in their tissues. wheat is one of the important cereal crops in bangladesh. wheat grown over an area of 3.74 million hectare with an annual production of about 1 million metric tons with an average of 2.60 t ha-1 (anonymous, 2011) in bangladesh. this production is less than that of the developed countries because about one third of the total area under wheat in bangladesh falls in the rainfed regions where water stress can limit plant growth and productivity due to very low or no rainfall (khaliq et al., 1999). in bangladesh wheat is grown in winter / rabi season (november to march) under rainfed condition. usually no significant precipitation takes place during this period. most of the farmers grow wheat without irrigation due to scarcity of water. some farmers provide supplemental irrigation by using surface water from the nearby ditches and canals. when the 98 jahan & ahmed source of surface water dried up the crop is subjected to drought. there is little scope to irrigate the crop with underground water. it is well known that the ground water table in bangladesh is declining day by day. the tendency of excess use of underground water for irrigation should be discouraged for maintaining ecological balance and healthy environment. as a result wheat faces drought stress at later stages that reduces grain yield drastically. the best option for crop production, yield improvement and yield stability under deficient soil moisture conditions is to develop drought tolerant crop varieties. new varieties must be developed that can withstand adverse climatic condition, particularly the soil moisture stress in order to produce increased yield per unit area. drought indices which provide a measure of drought based on loss of yield under drought conditions in comparison to normal conditions have been used for screening drought tolerant genotypes (mitra, 2001). keeping this view in mind, the present study was undertaken to evaluate the performance of wheat genotypes under drought condition, quantify yield loss due to drought and to screen out drought tolerant genotypes/varieties of wheat. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods the experiment was conducted in earthen pots under vinyl house at the research field of shere-bangla agricultural university campus during rabi season of 2013-2014. fifteen (15) genotypes of wheat (collected from wheat research center, bari) were evaluated under well irrigated (control) and drought conditions (table 1). drought treatment (which was started after emergence up to maturity) was imposed by restricting irrigation, and plants were re-irrigated only when plant showed signs of wilting or leaf rolling. control pots were irrigated as frequently as required to maintain adequate soil moisture. no rainfall occurred during experimental periods. the experiment was done in completely randomized design (crd) with five replications. earthen pot (20 cm top dia., 15 cm bottom dia. and 35 cm in height) were used in this study. table 1. list of wheat genotypes used in the present study variety/genotypes remark g1 bari gom 19 (sourav) variety g2 bari gom 20 (gourab) variety g3 bari gom 21 (shatabdi) variety g4 bari gom 22 (sufi) variety g5 bari gom 23 (bijoy) variety g6 bari gom 24 (prodip) variety g7 bari gom-25 variety g8 bari gom 26 variety g9 bari gom-27 variety g10 bari gom-28 variety g11 baw 1118 advanced line g12 baw 1135 advanced line g13 satyn-2 advanced line g14 satyn-25 advanced line g15 satyn-26 advanced line effect of drought stress on growth and yield pots were filled with soil and cowdung fertilizers @ 2.3-1-1-0.5 g/pot npks in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum were applied in the soil of each pot and incorporated properly. at sowing, 2/3 of urea and all other fertilizers were applied as basal. remaining urea was top-dressed at 20 days after sowing. seeds were sown in soil on 23 ten seeds were sown in each pot. one week after emergence, seedlings were thinned to three per pot. five pots were employed per treatment for each genotype. intercultural operations were done as and when required. at harvest, yield and yield contributing characters were recorded from 3 pots from each genotype. data were analyzed statistically software and mean separation was done by lsd test. stress tolerance index (sti) and geometric mean productivity (gmp) were calculated according fernandez (1992): yield stability index (ysi) was calculated stress susceptibility index (ssi) (fisher & maurer, 1978): where, ys and yp are the mean yield of genotypes under stress and non respectively and and are the mean conditions. results and discussionresults and discussionresults and discussionresults and discussion plant heightplant heightplant heightplant height plant height of the genotypes varied both in irrigated and drought stressed pots (fig. 1). in irrigated pots, plant height ranged from 88 to 95 cm. the in g14 followed by g15, g5 and g10 and the height reduced in all the genotypes compared to control and it ranged from 60 to 77 cm in different genotypes. plant height greatly red reduction in plant height in wheat due to drought was and nouri-ganbalani et al., (2009). number of spikes/plant number of spikes/plant number of spikes/plant number of spikes/plant the number of spikes/plant of the genotypes was significantly different both under control and drought condition (table 2). in control, the genotype g8 (9.3) which were statistically the second highest spikes/plant was recorded in g13 and g14. the lowest spikes/plant was found in genotype g7 (5.0) which were identical with g2, g6, g7, g9 and g16. under drought condition, number of spikes/plant was reduced in all nd yield of wheat genotypes pots were filled with soil and cowdung in 4: 1 volume ratio and final weight of pot was 14 kg. 0.5 g/pot npks in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum were applied in the soil of each pot and incorporated /3 of urea and all other fertilizers were applied as basal. remaining urea dressed at 20 days after sowing. seeds were sown in soil on 23rd november, 2013. ten seeds were sown in each pot. one week after emergence, seedlings were thinned to three er pot. five pots were employed per treatment for each genotype. intercultural operations were done as and when required. at harvest, yield and yield contributing characters were recorded from 3 pots from each genotype. data were analyzed statistically by using mstat and mean separation was done by lsd test. stress tolerance index (sti) and geometric mean productivity (gmp) were calculated according fernandez (1992): yield stability index (ysi) was calculated according to bouslama & schapaugh, 1984: ysi = ys/yp stress susceptibility index (ssi) (fisher & maurer, 1978): where, ys and yp are the mean yield of genotypes under stress and non-stress conditions, are the mean yield of all genotypes under stress and non-stress results and discussionresults and discussionresults and discussionresults and discussion plant height of the genotypes varied both in irrigated and drought stressed pots (fig. 1). in irrigated pots, plant height ranged from 88 to 95 cm. the maximum plant height was observed in g14 followed by g15, g5 and g10 and the shortest in g7. under drought stress, plant height reduced in all the genotypes compared to control and it ranged from 60 to 77 cm in different genotypes. plant height greatly reduced in g8, g11 and g13 due to drought. reduction in plant height in wheat due to drought was also reported by khakwani et al. (2012) the number of spikes/plant of the genotypes was significantly different both under control and drought condition (table 2). in control, the maximum number of spikes/plant was observed in were statistically identical with g10 and g3 but higher than others. the second highest spikes/plant was recorded in g13 and g14. the lowest spikes/plant was found in genotype g7 (5.0) which were identical with g2, g6, g7, g9 and g16. under drought condition, number of spikes/plant was reduced in all the genotypes. among the 99 in 4: 1 volume ratio and final weight of pot was 14 kg. 0.5 g/pot npks in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum were applied in the soil of each pot and incorporated /3 of urea and all other fertilizers were applied as basal. remaining urea november, 2013. ten seeds were sown in each pot. one week after emergence, seedlings were thinned to three er pot. five pots were employed per treatment for each genotype. intercultural operations were done as and when required. at harvest, yield and yield contributing characters were using mstat-c and mean separation was done by lsd test. stress tolerance index (sti) and stress conditions, stress plant height of the genotypes varied both in irrigated and drought stressed pots (fig. 1). in was observed under drought stress, plant height reduced in all the genotypes compared to control and it ranged from 60 to 77 cm in uced in g8, g11 and g13 due to drought. (2012) the number of spikes/plant of the genotypes was significantly different both under control and of spikes/plant was observed in than others. the second highest spikes/plant was recorded in g13 and g14. the lowest spikes/plant was found in genotype g7 (5.0) which were identical with g2, g6, g7, g9 and g16. under the genotypes. among the 100 jahan & ahmed genotypes, g8 showed the highest spikes/plant (4) which was identical with g10 and g14 and the lowest in g6 (1.3). these results are in agreement with the findings of (2012) who observed that drought caused reduct percent. g1= bari gom 19, g2= bari gom 20, g g6=bari gom 24, g7=bari gom-25 g g11=baw 1118, g12=baw 1135, g13=satyn number of grains/spikenumber of grains/spikenumber of grains/spikenumber of grains/spike genotypes varied in number of grains/spike both in irrigated and drought condition (table 2). however, under irrigated condition, the highest number of grains/spike was produced by g14 (49.2) which higher than g2 and g2 but identical with other genotypes. t grains/spike was recorded in g6 (35.6) all the genotypes produced lower number of grains/spike compared to control. of grains/spike was observed in g8 (40.6) g15 but significantly higher than other genotypes et al., (1994) reported that reduction in number of grains spike but the extent of reduction was different in various genotypes. 1000100010001000----grain weightgrain weightgrain weightgrain weight genotypes showed variation in grain size both in irrigated and drought condition (table 2). drought reduced grain sizes of all the genotypes. un was maximum in g2 (56.60 g) which was identical with g7, g8, g14 and g15 but significantly higher than other genotypes. moderate grain size was observed in g4, and g13 which ranged from 49.88 to g3 (43.2g) and it was identical with g5 and g9 weight was found in g2 (52.48g) which was statistically similar with g4, g6, g7, g8, g10, g14 and g15 but significantly higher than others. similar grain size and the lowest was found those reported by khan et al., (2005) who observed that 1000 reduced mainly due to increasing water stress. genotypes, g8 showed the highest spikes/plant (4) which was identical with g10 and g14 and the lowest in g6 (1.3). these results are in agreement with the findings of khakwani et al (2012) who observed that drought caused reduction in number of effective tillers plant-1 by 35 = bari gom 20, g3=bari gom 21, g4=bari gom 22, g5=bari gom 23, 25 g8=bari gom 26, g9=bari gom-27, g10=bari gom =satyn-2, g14=satyn-25, g15=satyn-26 genotypes varied in number of grains/spike both in irrigated and drought condition (table 2). however, under irrigated condition, the highest number of grains/spike was produced by g14 ch higher than g2 and g2 but identical with other genotypes. the lowest (35.6) and it was identical with g2 genotype. under drought, all the genotypes produced lower number of grains/spike compared to control. higher number of grains/spike was observed in g8 (40.6) which similar with g3, g10, g11, g12, g14 and g15 but significantly higher than other genotypes and the lowest in g6 (25.8). khannachopra ., (1994) reported that reduction in number of grains spike-1 in wheat under water stress but the extent of reduction was different in various genotypes. genotypes showed variation in grain size both in irrigated and drought condition (table 2). drought reduced grain sizes of all the genotypes. under irrigated condition, 1000-grain weight (56.60 g) which was identical with g7, g8, g14 and g15 but significantly moderate grain size was observed in g4, g6, g10, g11, g12 and g13 which ranged from 49.88 to 52.9 g. the lowest 1000-grain weight was recorded (43.2g) and it was identical with g5 and g9. in drought stress, the maximum 1000-grain (52.48g) which was statistically similar with g4, g6, g7, g8, g10, icantly higher than others. remaining genotypes showed statistically was found in g3 genotype. this result is in agreement with ., (2005) who observed that 1000-grain weight in wheat was mainly due to increasing water stress. genotypes, g8 showed the highest spikes/plant (4) which was identical with g10 and g14 and et al., by 35 =bari gom 23, =bari gom-28, genotypes varied in number of grains/spike both in irrigated and drought condition (table 2). however, under irrigated condition, the highest number of grains/spike was produced by g14 he lowest . under drought, number which similar with g3, g10, g11, g12, g14 and khannachopra in wheat under water stress genotypes showed variation in grain size both in irrigated and drought condition (table 2). grain weight (56.60 g) which was identical with g7, g8, g14 and g15 but significantly g6, g10, g11, g12 grain weight was recorded in grain (52.48g) which was statistically similar with g4, g6, g7, g8, g10, remaining genotypes showed statistically this result is in agreement with grain weight in wheat was 101 effect of drought stress on growth and yield of wheat genotypes grain yield grain yield grain yield grain yield grain yield/plant varied significantly among the genotypes both under control and drought stress conditions (table 2). under irrigated condition, the highest grain yield/plant (8.72 g) was produced by g14 which was significantly higher than g1, g2, g6, g7 and g13 but statistically identical with other genotypes. the lowest yield/plant (7.22 g) was recorded in g13 and it was identical with g1, g2, g6 and g7 genotypes. in drought stress, grain yield /plant were drastically reduced in all the genotypes and the maximum yield (7.00 g/plant) was found in g14 but similar with g8 and g10. the lowest grain yield/plant (2.52 g) was observed in g7 genotype which was identical with g6 genotype. rest of the genotypes gave moderate grain yield per plant which ranged from 4.28 to 5.39 g. the reason for lower grain yield under water stress condition was mainly due to reduction in number of effective tillers plant-1, spike length, number of grains spike-1 and 1000-grain weight. table 2. effect of drought stress on yield and yield contributing characters of wheat genotypes genotypes number of spikes/plant number of grains/spike 1000-grain wt. (g) grain yield/ plant (g) irrigated drought irrigated drought irrigated drought irrigated (yp) drought (ys) g1 7.0 2.0 47.0 27.6 49.88 46.16 7.59 4.50 g2 5.7 1.7 36.6 32.2 56.60 52.48 7.23 4.28 g3 9.0 2.7 43.4 37.8 43.20 40.64 8.45 4.80 g4 6.7 2.7 43.0 32.2 52.90 46.80 8.67 5.09 g5 7.3 2.5 47.4 37.6 45.12 40.76 8.69 4.65 g6 5.5 1.3 35.6 25.8 51.64 51.08 6.51 2.91 g7 5.0 1.7 45.0 33.0 54.24 49.64 6.17 2.52 g8 9.3 4.0 48.4 40.6 53.12 52.28 8.69 6.83 g9 6.0 1.3 42.4 31.6 45.68 44.56 8.22 5.04 g10 8.7 3.0 45.8 39.6 51.36 46.96 8.72 6.36 g11 6.7 1.7 42.6 39.0 50.40 45.32 7.71 4.50 g12 7.0 1.3 47.6 38.0 49.00 45.28 8.58 4.98 g13 8.0 2.7 45.6 34.8 50.56 40.36 7.22 5.39 g14 8.0 3.3 49.2 40.4 54.80 46.80 8.72 7.00 g15 6.0 2.0 42.2 37.4 55.20 50.36 8.40 5.28 lsd (0.05) 1.20 0.33 7.21 5.69 4.66 5.87 1.28 1.30 cv (%) 7.66 5.89 7.25 8.44 5.44 4.98 6.77 7.99 g1= bari gom 19, g2= bari gom 20, g3=bari gom 21, g4=bari gom 22, g5=bari gom 23, g6=bari gom 24, g7=bari gom-25 g8=bari gom 26, g9=bari gom-27, g10=bari gom-28, g11=baw 1118, g12=baw 1135, g13=satyn-2, g14=satyn-25, g15=satyn-26 relative yieldrelative yieldrelative yieldrelative yield among the genotypes, the highest relative yield was found in g14 followed by g8, g13 and g10 (fig. 2). the lowest relative yield was observed in g7 followed by g6 and g5. other genotypes showed almost similar relative yield. 102 jahan & ahmed g1= bari gom 19, g2= bari gom 20, g g6=bari gom 24, g7=bari gom-25 g g11=baw 1118, g12=baw 1135, g13=satyn yield reduction (%)yield reduction (%)yield reduction (%)yield reduction (%) drought reduced grain yield of all the genotypes (fig.3), however, yield reduction varied among the genotypes. the highest yield reduction was observed in g7 (about 59%) followed by (55%) and g5 (46%). the lowest yield reduction was observed in g14 (about 20%) followed by g8, g13 and g10. the average yield loss in wheat due to drought stress estimated by bayoumi et al., (2008) and khakwani et al., (2012) were 43.20 and 58 g1= bari gom 19, g2= bari gom 20, g g6=bari gom 24, g7=bari gom-25 g g11=baw 1118, g12=baw 1135, g13=satyn = bari gom 20, g3=bari gom 21, g4=bari gom 22, g5=bari gom 23, 25 g8=bari gom 26, g9=bari gom-27, g10=bari gom =satyn-2, g14=satyn-25, g15=satyn-26 drought reduced grain yield of all the genotypes (fig.3), however, yield reduction varied among the genotypes. the highest yield reduction was observed in g7 (about 59%) followed by (55%) and g5 (46%). the lowest yield reduction was observed in g14 (about 20%) followed by the average yield loss in wheat due to drought stress estimated by bayoumi ., (2012) were 43.20 and 58-82%, respectively. = bari gom 20, g3=bari gom 21, g4=bari gom 22, g5=bari gom 23, 25 g8=bari gom 26, g9=bari gom-27, g10=bari gom =satyn-2, g14=satyn-25, g15=satyn-26 =bari gom 23, =bari gom-28, drought reduced grain yield of all the genotypes (fig.3), however, yield reduction varied among the genotypes. the highest yield reduction was observed in g7 (about 59%) followed by g6 (55%) and g5 (46%). the lowest yield reduction was observed in g14 (about 20%) followed by the average yield loss in wheat due to drought stress estimated by bayoumi =bari gom 23, =bari gom-28, effect of drought stress on growth and yield straw yield (g/plant) straw yield (g/plant) straw yield (g/plant) straw yield (g/plant) in control condition, the maximum straw yield was obtained from g5 and g12 followed by g14. moderate straw yield was observed in g1, g2, g4, g6, g8, g9, g10 and g15 and t lowest straw yield was found in g13 g12 showed higher straw yield while the lowest in g3 and g5 g1= bari gom 19, g2= bari gom 20, g g6=bari gom 24, g7=bari gom-25 g g11=baw 1118, g12=baw 1135, g13=satyn stress tolerance indicesstress tolerance indicesstress tolerance indicesstress tolerance indices stress indices like geometric mean productivity (gmp), stress tolerance index (sti), stability index (ysi) and stress susceptible index (ssi) are shown in table 3. table 3.tolerance indices of 15 wheat genotypes under variable water regimes genotypes yp bari gom 19 7.59 bari gom 20 7.23 bari gom 21 8.45 bari gom 22 8.67 bari gom 23 8.69 bari gom 24 6.51 bari gom-25 6.17 bari gom 26 8.69 bari gom-27 8.22 bari gom-28 8.72 baw 1118 7.71 baw 1135 8.58 satyn-2 7.22 satyn-25 8.72 satyn-26 8.40 yp= control yield, ys= water deficit yield, gmp= geometric mean productivity, sti= stress tolerance index, ysi= yield stability index, ssi= stress susceptibility index 103 nd yield of wheat genotypes straw yield was obtained from g5 and g12 followed by moderate straw yield was observed in g1, g2, g4, g6, g8, g9, g10 and g15 and t (fig.4). under drought stress, g2, g4, g9, g10, g11, straw yield while the lowest in g3 and g5 genotypes. = bari gom 20, g3=bari gom 21, g4=bari gom 22, g5=bari gom 23, 25 g8=bari gom 26, g9=bari gom-27, g10=bari gom =satyn-2, g14=satyn-25, g15=satyn-26 stress indices like geometric mean productivity (gmp), stress tolerance index (sti), yield susceptible index (ssi) are shown in table 3. table 3.tolerance indices of 15 wheat genotypes under variable water regimes ys gmp sti ysi ssi 4.50 5.84 0.54 0.59 1.08 4.28 5.56 0.49 0.59 1.08 4.80 6.37 0.64 0.57 1.15 5.09 6.64 0.69 0.59 1.10 4.65 6.36 0.64 0.54 1.24 2.91 4.35 0.30 0.45 1.47 2.52 3.94 0.24 0.41 1.57 6.83 7.70 0.93 0.79 0.57 5.04 6.44 0.65 0.61 1.03 6.36 7.45 0.87 0.73 0.72 4.5 5.89 0.55 0.58 1.11 4.98 6.54 0.67 0.58 1.12 5.39 6.24 0.61 0.75 0.67 7.00 7.81 0.96 0.80 0.52 5.28 6.66 0.70 0.63 0.99 yp= control yield, ys= water deficit yield, gmp= geometric mean productivity, sti= stress tolerance index, ysi= yield stability index, ssi= stress susceptibility index 103 straw yield was obtained from g5 and g12 followed by moderate straw yield was observed in g1, g2, g4, g6, g8, g9, g10 and g15 and the g2, g4, g9, g10, g11, =bari gom 23, =bari gom-28, yield 1.08 1.08 1.15 1.10 1.24 1.47 1.57 0.57 1.03 0.72 1.11 1.12 0.67 0.52 0.99 yp= control yield, ys= water deficit yield, gmp= geometric mean productivity, sti= stress tolerance 104 jahan & ahmed the maximum gmp was found in g14 (7.81) followed by g8 (7.70) and g10 (7.45) while the lowest gmp was found in g7 (3.94). sti also followed similar trend where g14 gave the maximum sti (0.96) followed by g8 and g10 and the lowest in g7. higher ysi was observed in g14 followed by g8 and g10 and the lowest in g7. the maximum ssi was observed in g7 followed by g6 and g12. the lowest ssi value was found in g14 (0.52) conclusionconclusionconclusionconclusion from the above results, it may be concluded that genotypes bari gom-26, bari gom-28 and satyn-25 could be selected as drought tolerant genotypes on the basis of yield and stress tolerance indices. however, for confirmation of the result further study is needed. referencesreferencesreferencesreferences anonymous. 2011. year book of agricultural statistics of bangladesh, bangladesh bureau of statistics (bbs), ministry of planning, government of the people’s republic of bangladesh. bayoumi, t. y., m. h. eid and e. m. metwali. 2008. application of physiological and biochemical indices as a screening technique for drought tolerance in wheat genotypes. afri. j. biotech. 7: 2341-2352. golbashy, m., m. ebrahimi, s. k. khorasani, and r. choukan. 2010. evaluation of drought tolerance of some corn (zea mays l.) hybrids in iran. afr. j. agric res. 5(10) : 2714 – 2719. jaleel, c. a., p. manivannan, a. wahid, m. farooq, h. j. al-juburi, r. somasundaram and r. panneerselvam. 2009. drought stress in plants: a review on morphological characteristics and pigments composition. int. j. agric. biol. 11(1): 100–105. khakwani, a. a., m. d. dennett, m. munir and m. abid. 2012. growth and yield response of wheat varieties to water stress at booting and anthesis stages of development. pak. j. bot. 44(3): 879-886. khaliq, i., s. a. h. shah, m. ahsan and m. khalid. 1999. evaluation of spring wheat (triticum aestivum l.) for drought field conditions. a morphological study. pak. j. biol. sci. 2(3): 1006-1009. khan, a. j., f. azam, a. ali, m. tariq and m. amin. 2005. inter-relationship and path co-efficient analysis for biometric traits in drought tolerant wheat (triticum aestivum l.). asian j. plant sci. 4(5): 540-543. khannachopra, r., s. s. p. rao, m. maheswari, i. xiabing and s. k. shivshankar. 1994. effect of water deficit on accumulation of dry matter, carbon and nitrogen in the kernel of wheat genotypes differing in yield stability. ann. bot. 74(5): 503-511. lawlor, d. w. and g. cornic. 2002. photosynthetic carbon assimilation and associated metabolism in relation to water deficits in plants, plant cell environ. 25: 275–294. ludlow, m. m. and r. c. muchow. 1990. a critical evaluation of traits for improving crop yields in water limited environments, adv. agron. 43: 107–153. mitra, j. 2001. genetics and genetic improvement of drought resistance in crop plants. curr sci. 80: 758-762. 105 effect of drought stress on growth and yield of wheat genotypes nikus o, m. a. turk, a. m. al-tawaha. 2004. yield responses of sorghum (sorghum bicolor, l) to manure supplemented with phosphate fertilizer under semi-arid mediterranean conditions. int j agric biol 6: 889-893. nouri-ganbalani, a., g. nouri-ganbalani and d. hassanpanah. 2009. effect of drought stress condition on the yield and yield components of advanced wheat genotypes in ardabil, iran. j. food agric. environ. 7: 228-234. zhu, j. k. 2002. drought stress signal transduction in plants, annu. rev. plant biol. 53: 247–273. bangladesh agron. j. 2019, 22 (1): 47-56 physiological and yield responses of some selected rapeseed/ mustard genotypes to high temperature stress faruque ahmed*1, i.m. ahmed1, n. mokarroma1 f. begum2 and a. jahan3 1plant physiology division, bari, gazipur-1701 2oilseed research center, bari, gazipur-1701 3department of soil science, sau, dhaka-1207 *corresponding e-mail: faruquebari@gmail.com (received: 24 april 2019, accepted: 24 october 2019) keywords: high temperature, stress, physiology, rapeseed/mustard, genotypes, yield abstract a pot experiment was conducted with five selected rapeseed/mustard genotypes (bjdh-11, bjdh-12, bjdh-20, bari sarisha-14, and bari sarisha-16) under two sowing dates (november 20 and december 20) for evaluating their responses to sowing date induced high temperature stress during rabi season of 2017-18. sowing dates induced temperature variability showed remarkable changes in pheonlogy, leaf area, leaf chlorophyll content, dry matter production and seed yield. although december 20 sown crop received lower temperatures (minimum 9.8 to 13.2 and maximum 22.6 to 27oc) than november 20 sown crop (minimum 14.8 to 16.4 and maximum 21 to 27.2oc) at flowering but reverse was found at grain development stage. grain development stage of november 20sown crop received lower temperatures (minimum 8.2 to 13.2 and maximum 24.1 to 27 oc) while december 20 sown crop received higher temperatures at grain development stage (minimum 8.2 to 18 and maximum 22.6 to 32.5oc).as a result december 20 sown crop matured earlier (6 to 9 days) than november 20 sown crop. leaf area/plant was higher in december 20 sown crops compared to november 20 sown but total dry matter production was more or less same in both the sowing dates. leaf chlorophyll content did not show any remarkable variation due to variation in sowing dates. however, antioxidant activity like catalyse (cat), peroxidase (pod) ascorbate peroxidase (apx) and malondial dehyde (mda) were found higher in december 20 sown crops than that of november 20sown. higher activity of apx, pod and cat with lower activity of mda indicates comparatively high temperature tolerant genotype. among the genotypes apx, pod and cat activity were found higher with lower activity of mda in bjdh-11 and bjdh-20 and these genotypes also gave higher yield than others. on the basis of growth parameters, antioxidant activity and seed yield of genotype bjdh-11 and bjdh-20 could be select as terminal high temperature tolerance genotypes. introduction high temperature stress is the most important abiotic stress affecting plant productivity around the world (hall, 1992). the rising atmospheric co2 and temperature are the two important factors of climate change which are likely to impact agriculture and food security across the globe. despite some projected increase in photosynthesis due to higher atmospheric co2, increased temperature results in reduced productivity (wassmann et al., 2009). the global average air temperature is expected to rise by 1.8 to 40 c by the end of this century. the rabi season temperature is expected to increase more than the kharif season 56 ahmed et al. (aggarwal and mall, 2002). rapeseed/mustard constitute an important source of edible oiling bangladesh. it grows under diverse agro-ecological situations such as timely/late sown, rainfed/irrigated, sole or mixed crop with cereals (wheat, barley etc.) and rabi (october-march) pulses (chickpea, lentil etc.), where high temperature is the main constraint not only at germination but also at grain filling stage. generally, plants respond to high temperature stress through developmental, biochemical and physiological changes and the type of the observed response depends on several factors such as stress intensity, stress duration and genotype (moradshahi et al., 2004). flowering and grain filling are the most sensitive stages for temperature stress damage probably due to vulnerability during pollen and grain development, anthesis and fertilization leading to reduce crop yield (hall, 1992). high temperature in brassica enhanced plant development and caused flower abortion and poor grain filling with appreciable loss in seed yield. a rise of 30c in maximum daily temperature (21-240c) during flowering and grain filling caused a decline of 430 kg/ha in canola seed yield (singh et al., 2014). therefore, improving seed yield of rapeseedmustard under late sown conditions is main challenge for rapeseed mustard research. hence there is need to develop terminal heat tolerant genotype on the basis of desirable physiological traits. materials and methods a pot experiment was conducted at the research field of plant physiology division, bari gazipur during rabi season of 2017-18. five selected genotypes namely: bjdh-11, bjdh-12, bjdh-20, bari sarisha-14 (bari_14), and bari sarisha-16(bari-16) were used as test crop under two sowing dates november 20 and december 20. the experiment was laid out in randomized complete block design with 10 replications. plastic pot (top dia: 25 cm, bottom dia: 18 cm and height 25cm; 12 kg soil) was filled up with soil and cowdung (4:1). ten seeds were sown in each pot according to treatments. fertilizers were applied 100-30-80-20-3-1 kg/ha npksznb. half of n and all other fertilizers were applied as basal and remaining n was applied at 20 das. irrigation was done as and when required for maintaining adequate soil moisture. after emergence plants were thinned to three plants in each pot. plants from three pots were sampled for leaf area and dry matter measurement at different growth stages. sampled plants were separated into leaf, stem and siliqua. leaf area was measured by an automatic area meter (li-3100 c; li-cor, usa). plant parts were dried in an oven for 72 hours at 70oc and dry weight was recorded. at harvest yield and yield components data were collected from three pots and analyzed statistically and mean separation was done by lsd test at 5% level of significance. chlorophyll estimation leaves (3rd leaf from top)of each genotype were collected on 55 das for chlorophyll measurement. leaves were properly cut into small pieces and weighed 0.5 g and were taken for chlorophyll estimation. chlorophyll a, chlorophyll b and total chlorophyll were estimated following arnon’s method (arnon, 1949). the absorbance of the solution was read at 645 and 663 nm for chlorophyll a, chlorophyll b and total chlorophyll. calculation: chlorophyll a (mg g-1) = {12.7 (d663) 2.69 (d645)} × v/( 1000 × w) chlorophyll b (mg g-1) = {22.9 (d645) 4.68 (d663)} × v/(1000 × w) total chlorophyll (mg g-1) = 20.2 (d645) + 8.02 (d663) × v/( 1000 × w) where d = optical density v = final volume of 80% acetone (ml) physiological and yield response of rapeseed/mustard 49 w = dry weight of sample taken (g) bio-chemical analysis leaf samples (3rd leaf from top) were collected on 55 das for antioxidant enzyme like catalyse (cat), ascorbate peroxidase (apx) and peroxidase (pod) and malondialdehyde (mda) determination. enzyme extraction and assays using a pre-cooled mortar and pestle, 0.5 g of leaf tissue was homogenized in 1 ml of 50 m m ice-cold k-phosphate buffer (ph 7.0) containing 100 m mkcl, 1m mascorbate, 5 m mβ-mercaptoethanol, and 10% (w/v) glycerol. the homogenates were centrifuged at 11,500×g for 10 min, and the supernatants were used for determination of enzyme activity. all procedures were performed at oc to 4°oc. determination of protein the protein concentration of each sample was determined following the method of bradford (1976) using bsa as a protein standard where 5, 10, 15, 20, 25 μgμl-1 protein concentrations were used to prepare standard curve. peroxidase (pod, ec 1.11.1.7): pod activity was estimated according to hemeda and klein (1990). the reaction mixture contained 25 m m k-p buffer (ph 7.0), 0.05% guaiacol, 10 mm h2o2 and enzyme. activity was determined by the increase in absorbance at 470 nm due to guaiacol oxidation for 1 min using extinction coefficient of 26.6 mm-1 cm-1. catalase (cat, ec: 1.11.1.6): cat activity was measured according to the method of hossain et al. (2010) by monitoring the decrease of absorbance at 240 nm for 1 min caused by the decomposition of h2o2. the reaction mixture contained 50 m m k-phosphate buffer (ph 7.0), 15 m m h2o2, and enzyme solution in a final volume of 0.7 ml. the reaction was initiated with enzyme extract, and the activity was calculated using the extinction coefficient of 39.4 m−1 cm−1. ascorbate peroxidase (apx, ec: 1.11.1.11) activity was assayed following the method of nakano and asada (1981). the reaction buffer solution contained 50 m m k-phosphate buffer (ph 7.0), 0.5 m masc, 0.1 m m h2o2, 0.1 m medta, and enzyme extract in a final volume of 0.7 ml. the reaction was started by the addition of h2o2, and the activity was measured by observing the decrease in absorbance at 290 nm for 1 min using an extinction coefficient of 2.8 mm−1 cm−1. lipid peroxidation the level of lipid peroxidation in plant tissues was expressed as 2-thiobarbituric acid (tba) reactive metabolites, mainly malondialdehyde (mda), and was determined according to hodges et al. (1999). fresh samples (leaves) of around 0.5 g were homogenizedin 4.0 ml of 1% trichloroacetic acid (tca) solution and centrifuged at10,000×g for 10 min. the supernatant was added to 1ml 0.5% (w/v)tba made in 20% tca. the mixture was heated in boiling water for30 min, and the reaction was stopped by placing the tubes in anice bath. the samples were centrifuged at 10,000×g for 10 min, and the absorbance of the supernatant was recorded at 532 nm. correction of non-specific turbidity was made by subtracting the absorbance value read at 600 nm. the level of lipid per-oxidation was expressed as nmol g−1 fresh weight, with a molar extinction coefficient of 0.155 mmcm−1. 56 ahmed et al. results and discussion phenology there was variability in days required for emergence of the genotypes in november 20 sown; bjdh-11 and bari sarisha-14 took five days while others took 6 days for emergence. but in december 20 sowing all the genotypes took four days for emergence. generally december 20 sowing took less days for emergence compared to november 20 sown due to higher temperature at sowing. flowering was delayed in 20 december sown than november 20 sown in all the genotypes except bari sarisha-14 which took same days for flowering in both the sowing dates. november 20 sown genotypes flowered within 28-34 days while that was 28-37 days for december 20 sown. among the genotypes early flowering was observed in bari sarisha-14. in december 20 sown, all the genotypes matured earlier than november 20 sowing (fig. 3). temperature regime fig. 4 shows the air temperatures (maximum and minimum) during crop growing periods. on november 20 sowing crop emerged when maximum and minimum temperatures were >30 and >15oc but on december 20 sown crop emerged when those were <30 and < 15oc, as a result december sown took more days for emergence than november sown. november 20 sowing crop flowered when maximum temperatures were around 26-27oc and minimum temperature were around 13-15oc but at flowering december 20sowncrop received 24-26oc as maximum and 9-12oc as minimum temperatures. after flowering november physiological and yield response of rapeseed/mustard 51 20sowncrop received lower temperatures than december 20 sown crop up to harvest as a result december 20 sown crop matured earlier than november 20 sown crop. leaf area/plant fig. 5 and fig.6 shows leaf area/plant of the genotypes at november 20 and december 20sown. in both the sowing dates, leaf area increased up to 50 days after sowing; there after it decreased due to leaf senescence. in november 20 sown maximum leaf area was observed in bjdh-11 and bari sarisha-16 throughout the growing periods followed by bjdh-12 and bjdh-20. lower leaf area/plant was observed in bari sarisha-14 throughout the growing season. in december 20 sowing maximum leaf area was observed in bari-16 (bari sarisha-16) and bjdh-11 at 50 das followed by bjdh-12 and bjdh-20 and minimum in bari sarisha-14. total dry matter (tdm) tdm in both the sowing dates increased up to harvest (fig. 7 and 8). at both the sowing dates higher tdm was observed in bjdh-11, bjdh-12, bjdh-20 compared to others and the lowest tdm was observed in bari sarisha-14. tdm production was almost similar at both the sowing dates. 56 ahmed et al. antioxidant activity apx activity increased due to higher temperature stress in december 20 sowing compared to november 20 sowing in all the genotypes (fig.9). maximum apx activity was found in bari sarisha-14 followed by bari sarisha-16, bjdh-20 and bjdh-11 and the lowest in bjdh-12. higher pod activity was observed in bjdh-11 followed by bjdh-20 and the minimum was found in bari sarisha-16 (fig.10). apx and pod enzyme were increased in tolerant genotype but decreased in susceptible genotype (babita rani et al., 2016). catalyze activity of december 20 sowing was higher than november 20 sowing irrespective of genotypes (fig.11). highest cat activity was found in bjdh-20 followed by bari sarisha-16 and the lower cat activity was found in bjdh-12 in both the sowing dates. soengas (2018) reported higher cat activity in brassica under heat stress than under control condition. the enzymatic activity of cat was significantly higher under heat than under control conditions for both sown crops. the activities of superoxide dismutase (sod), catalase (cat) and peroxidase (pox) and the level of prolineexhibited increases in response to heat stress application (hayat et al., 2009). heat stress induces oxidative stress. for example, generation and reaction of activated oxygen species (aos), which causes the autocatalytic per-oxidation of membrane lipids and pigments subsequently leads to membrane permeability and modification of its functions (xu et al., 2006). highest mda activity was observed in bari sarisha-14, bjdh-12 and bari sarisha-16 and the lowest mda activity was found in bjdh-11 and bjdh-20 physiological and yield response of rapeseed/mustard 53 (fig.12). lower mda was reported in tolerant genotypes of brassica juncea compared to susceptible genotypes by wilson et al. (2014). leaf chlorophyll content table 1 shows leaf chlorophyll content at pre-flowering stage of the genotypes at two sowing dates. chlorophyll content of the genotypes at november 20 sowing and december 20 sowing did not show any remarkable differences although december 20 sowing showed comparatively higher values. table 1. leaf chlorophyll content in rapeseed-mustard genotypes at pre-flowering stage nov-20 sowing (mg/g fw) dec-20 sowing (mg/g fw) chl a c hl b chl (a+b) chl a c hl b chl (a + b) bjdh-11 0.701424 0.325616 1.02704 0.709556 0.451198 1.160754 bjdh-12 0.710594 0.349883 1.060477 0.71121 0.365893 1.077103 bjdh-20 0.711819 0.449487 1.161306 0.706173 0.370602 1.076775 bari-14 0.703127 0.575345 1.278472 0.71082 0.425061 1.135881 bari-16 0.715644 0.386859 1.102503 0.712259 0.381305 1.093564 se  0.038778 0.112077 0.155606 0.004771 0.154315 0.121301 bari-14 = bari sarisha-14, bari-16 = bari sarisha-16 yield and yield components effect of sowing dates sowing dates induced temperatures variability showed significant influence on yield and yield components (table 2). plant height of december 20 sowing was significantly higher than that of november 20 sowing while the reverse results were observed in other parameters. significantly higher number of siliquae/plant, seeds/siliqua was observed in november 20 sowing compared to december 20 sowing. seed size reduced significantly in december 20 sowing compared to november 20 sowing. significant yield reduction was observed due to sowing date induced high temperature stress. chauhan et al. (2009) also reported yield reduction due to temperature stress in indian mustard. aksouh et al. (2001) reported that heat stresses reduced the number of siliquaper plant, number of seeds per siliqua, and 1000-seed weight. effect of genotypes 56 ahmed et al. genotypes showed significant variability in all the characters (table 3). the maximum plant height was observed in bjdh-12 which was identical with bjdh-11, bjdh-20 and bari sarisha-16 but significantly higher than bari sarisha-14. the maximum number of branches/plant was found in bari sarisha14 which was identical with bjdh-11 but significantly higher than other genotypes. among the genotypes, significantly highest number of siliqua/plant (207.38) was recorded in bjdh-11.the second highest siliqua/plant (156.54) was observed in bari sarisha-16 which was identical with bjdh-20 and bjdh-12 but significantly higher than bari sarisha-14. the highest number of seeds/siliqua (36) was found in bari sarisha-14 which was significantly higher than other genotypes. the second highest seeds/siliqua (15) was found in bari sarisha-16 which was significantly higher than other genotypes. the lowest seeds/siliqua was recorded in bjdh-12 which was identical with bjdh-11 and bjdh-12. the highest 1000-seed weight was recorded in bjdh-20 which was significantly higher than other genotypes. the second highest 1000-seed weight was found in bjdh-12 which was significantly higher than others. the lowest 1000-seed weight was found in bari sarisha-14. the highest seed yield was observed in bjdh-11 which was significantly higher than other genotypes. the second highest seed yield was recorded in bjdh-20 which was identical with other genotypes and the lowest seed yield in bari sarisha -14. table 2. effect of sowing dates on yield and yield contributing characters of rapeseed-mustard (2017-18) sowing date plant height (cm) branches/ plant (no.) siliqua/ plant (no.) seeds/ siliqua (no.) 1000-seed wt. (g) seed yield/plant (g) nov-20 125.00 5.65 156.15 18.58 4.05 6.20 dec-20 140.35 4.70 138.10 17.20 3.46 4.50 lsd (0.05) 6.55 0.46 12.41 1.22 0.20 0.45 cv(%) 7.60 11.53 10.67 10.50 8.10 10.11 table 3. effect of genotypes on yield and yield contributing characters of rapeseed-mustard (2017-18) genotype plant height (cm) branches/ plant (no.) siliqua/ plant (no.) seeds/ siliqua (no.) 1000-seed weight (g) seed yield/ plant (g) bjdh-11 142.25 6.00 207.38 13.00 3.54 6.27 bjdh-12 149.13 5.00 153.71 13.00 3.94 5.05 bjdh-20 141.63 4.00 155.00 12.00 4.36 5.37 bari-14 90.13 6.00 63.00 36.00 3.28 4.70 bari-16 140.25 5.00 156.54 15.00 3.65 5.36 lsd (0.05) 10.36 0.72 19.62 1.93 0.31 0.71 cv (%) 7.60 11.53 10.67 10.50 8.10 10.11 conclusion on the basis of physiological parameters, antioxidant activity and seed yield, the mustard genotype, bjdh-11 and bjdh-20 could be selected as terminal high temperature (3 to 4 oc higher than average temperature)tolerant genotypes. references physiological and yield response of rapeseed/mustard 55 aggarwal, p.k. and r.k. mall. 2002. climate change and rice yields in diverse agro-environments of india. ii, effect of uncertainties in scenario and crop models on impact assessment. climate change 52: 331-343. aksouh, n.m., b.c. jacobs, f.l. stoddard and r.j. mailer. 2001. response of canola to different heat stresses. aust. j. agric. res. 2001. 52: 817– 824. arnon, d. 1949. copper enzyme in isolated chloroplast and poly phenol oxidase in beta vulgaris. plant physiol. 24: 1-7. babita rani, n. kumari, pooja, v. jain, k. dhawan, monika, r. avtar, a. kumar and p. sheoran. 2016. antioxidative system as influenced by high temperature stress in brassica juncea. current trends in biotechnology and pharmacy. 10(2): 118-125. bradford, m.m. 1976. a rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. analytical biochemi. 72: 248–254. chauhan, j.s., m.l. meena, m. saini, d.r. meena, m. singh, s.s. meena and k.h. singh. 2009. heat stress effects on morpho-physiological characters of indian mustard (brassica juncea l.). paper presented in 16th australian research assembly on brassicas. ballarat, victoria, australia. september 14-16. hall, a.e. 1992. breeding for heat tolerance. plant breeding rev. 10: 129-168. hayat, s.a. masood, m. yusuf, q. fariduddin, and a. ahmad. 2009. growth of indian mustard (brassica juncea l.) in response to salicylic acid under high-temperature stress. braz. j. plant physiol. 21(3): 187-195. hemeda, h.m. and b.p. klein. 1990. effects of naturally occurring antioxidants on peroxidase activity of vegetable extracts. j. food sci. 55: 184-185. hodges, d.m., j.m. delong, c.f. forney and r.k. prange. 1999. improving the thiobarbituric acid-reactivesubstances assay for estimating lipid peroxidation in plant tissues containing anthocyanin and other interfering compounds. planta 207: 604–611. hossain, m.a., m. hasanuzzaman and m. fujita. 2010. up-regulation of antioxidant and glyoxalase systems by exogenous glycinebetaine and proline in mungbean confer tolerance to cadmium stress. physiol. molecular biol. plants. 16: 259–272. moradshahi, a., b. salehi eskandari and b. kholdebarin. 2004. some physiological responses of canola (brassica napus l.). iranian j. sci. tech. trans. asci., 28, pp.43–50 (in persian). nakano, y. and k. asada. 1981. hydrogen peroxide is scavenged by ascorbatespecific peroxidase in spinach chloroplasts. plant cell physiol. 22: 867880. singh, m., s.s. rathore and p. raja. 2014. physiological and stress studies of different rapeseed-mustard genotypes under terminal heat stress. int. j. genetic eng. biotech. 5(2): 133-142. soengas, p.v.m. rodríguez, p. velasco and m.e. cartea. 2018. effect of temperature stress on antioxidant defenses in brassica oleracea. acs omega. 3: 5237-5243. 56 ahmed et al. wassmann, r., s.v.k. jagadish, k. sumfleth, h. pathak, g. howell, a. ismail, r. serraj, e. redona, r.k. singh and s. heuer. 2009. regional vulnerability of climate change impacts on asian rice production and scope for adaptation. advn. agron. 102: 91-133. wilson, r.a., m.k. sangha, s.s. banga, a.k. atwal and s. gupta. 2014. heat stress tolerance in relation to oxidative stress and antioxidants in brassica juncea. j. environ. biol. 35(2): 383-387. xu, s., li, j., x. zhang, h. wei and l. cui. 2006. effect of heat acclimation pretreatmenton changes of membrane lipid peroxidation, antioxidant metabolites, and ultra-structure of chloroplasts in two cool-season turf grass species under heat stress. environ. expt. bot. 56: 264-285. bangladesh agron. j. 2017, 20 (1): 99-105 performance of intercropping groundnut with sesame m. a. h. khan, n. sultana, s. akhtar, n. akter and m. s. zaman on-farm research division bangladesh agricultural research institute, mymensingh, bangladesh corresponding author: helim1367@gmail.com key words: intercropping, productivity, equivalent yield, land equivalent ratio and harvest index abstract the experiment was carried out at the farmers’ field of on-farm research division, bangladesh agricultural research institute (bari), mymensingh during two consecutive years 2015 and 2016 to find out the suitable intercropping system for increasing crop productivity and profitability of groundnut with sesame intercropping system. the treatments were t1=sole groundnut, t2=sole sesame, t3= two rows of groundnut in between paired rows of sesame and t4= three rows of groundnut in between paired rows of sesame. treatments were arranged in a randomized complete block design with six dispersed replications. between intercropped treatments, three rows of groundnut within paired rows of sesame showed higher sesame equivalent yield (2.33 tha-1) and groundnut equivalent yield (2.14 tha-1) which provided the yield advantages of 108 and 32% over the respective sole crops. the highest land equivalent ratio (1.64), gross return (tk 1,28,350 ha-1) and benefit cost ratio (2.15) were also achieved in three rows of groundnut within paired rows of sesame compared to other intercropping and sole cropping systems. the result showed that three rows of groundnut in between paired rows of sesame is found most productive and profitable than sole sesame or sole groundnut for maximum profit in mymensingh region introduction bangladesh is an agriculture based country and about 14.75 % gross domestic product (gdp) comes from agriculture in bangladesh (ais, 2017). the main challenge of the new millennium is to increase yield of per unit area by at least 50 % through manipulating the limited land resource. sesame (sesamum indicum l.) is an important oilseed crop ranked second-in terms of acreage (38057 ha) of land and produces 36,000 metric tons of sesame seeds with an average yield of 860 kg ha-1 (bbs, 2015). it can be cultivated both in kharif and rabi seasons. sesame is a drought resistant crop. it cannot tolerate water logging or excess moisture in the field. seeds contain 42-45 % oil and 20 % protein (mondal and wahhab, 2001). the cultivation of sesame is drastically declining due to widely increasing of rice, maize and mungbean cultivation in kharif-i season. moreover, sesame competes with jute and different vegetables in the season. intercropping plays an important role in increasing the productivity and stability of yield in order to improve resource utilization and environmental factors (alizadeh et al., 2010). research in different countries reveals that intercropping has several benefits to the farmers including reduction in farm inputs, diversification of diet, addition of cash crops, increased labour utilization efficiency, reduced risk of crop failure, more efficient use of water resources, nutrients and reduced problems caused by pests, diseases and weeds (awal et al., 2006). so, intercropping of sesame with groundnut could help to retain oilseed crops and ensure highest productivity per unit area as well as supply of oil . groundnut (arachis hypogaea l.) is the third 100 khan et al. most important legume crop in bangladesh which grown on 31,579 ha of land and produces 56713 metric tons of nut with an average yield of 1.79 t ha-1 (bbs, 2015). recently the area of groundnut is being decreased due to the competition with rabi crops like wheat, potato, boro rice and mustard (alom et. al., 2009). moreover, most of the char land of bangladesh become inundated in kharif season which also one of the causes the decline of groundnut production area. some experimental evidences showed that in the sesame field groundnut can be grown as intercrop. groundnut var. bari chinabadam-8 is short in stature and suitable for early kharif and late kharif planting. groundnut can withstand excessive rainfall. so, if sesame crop is damaged due to heavy rainfall, groundnut crop will thrive and farmers will not lose their crops fully. the research findings stated that nitrogen fixation in groundnut and the residual benefits through incorporation of stover to subsequent crops were estimated in farmers’ fields (mondal and wahhab, 2001). better intercrop production could be achieved with the choice of appropriate crops population density and planting geometry of component crops (santalla et al., 2001). groundnut and sesame in intercropping systems may increase their production and profit. in this context, the experiment was conducted to find out the suitable intercrop combination of sesame with groundnut for higher productivity and profitability. materials and methods the experiment was carried out at the farmers’ field of on-farm research division, bangladesh agricultural research institute (bari), mymensingh during two consecutive years 2015 and 2016 to find out the suitable intercropping system for increasing crop productivity and profitability of groundnut sesame intercropping system. the experimental soil was sandy loam to silty loam of the medium highland having ph 6.2 to 6.5 under the agro-ecological zone-9 (aez-9). the treatments were as t1= sole groundnut, t2= sole sesame, t3= two rows of groundnut in between paired rows of sesame and t4= three rows of groundnut in between paired rows of sesame. groundnut var. bari chinabadam-8 and sesame var. bari til-4 were used. the experiment was laid out in a randomized complete block design with six dispersed replications. the unit plot size was 8.0 m x 5.0 m. the seeds of sesame were sown in 30 cm apart paired rows and 75 cm between two pairs with 5 cm between the plants. the spacing maintained for sole groundnut was 25 cm x 10 cm for intercropping system, the plant population of sesame plots remained same as sole plot but it varied for groundnut. the seed germination of both crops was 95 percent. seeds of both crops were sown on 07 to 14 march 2015 and 2016. fertilizers were applied at the rate of 15-32-42-27-2-2 kg npksznb ha-1 in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid, respectively (mondal and wahhab, 2001). all fertilizers were applied as basal during final land preparation by broadcasting method. additional 20 kg ha-1 of urea applied as top dressed in between two rows of sesame at 25-30 das. thinning was done after 15-20 days of seed germination in both the years. mulching and hand weeding were done as and when necessary to keep the field reasonable weed free. dursban 2ml l-1 water was sprayed at 15-20 days intervals as precautionary measure against insects attack. dithane m-45 2g l-1 water was sprayed at 15 days intervals at the later stages of groundnut as precautionary measure from prevalence of disease. seed, pod and straw yields at harvest were converted into tha-1 after proper drying. sesame was harvested on 07-10 june 2015 and 08-12 june 2016 and groundnut on 07-14 july 2015 and 15-21 july 2016 at physiological maturity.. 101 performance of intercropping groundnut with sesame pest and disease incidence: nitro @ 2mll-1 water was sprayed twice at 10 days interval for successful controlling the hairy caterpillar and thrips. stem rot of sesame was observed sporadically in the flowering stage of sesame; baiting @ 2gl-1 water was sprayed twice at 7 days interval for controlling fungal disease. no other disease and insects infestation was observed during the cropping period. the yield contributing characters of sesame and groundnut were recorded from 10 randomly selected plants in both the years. harvest index (hi) was calculated as per following equation: hi (%) = 100 yield biological yieldgrain yield of individual crop was converted into equivalent yield on the basis of the prevailing market price of individual crop (prasad and srivastava, 1991). sesame equivalent yield (sey) = yield of intercrop sesame + ps pgyig and groundnut equivalent yield (gey) = yield of intercrop groundnut + pg psyis where, yig= yield of intercrop groundnut, pg= price of groundnut, ps= price of sesame and yis= yield of intercrop sesame in intercropping systems, relative yield was quantified by (jokinen, 1991). relative yield of sesame (rys): yss yis , relative yield of groundnut (ryg): ysg yig and relative yield total (ryt): rys + ryg, where yss= yield of sole sesame, yis= yield of intercrop sesame, ysg= yield of sole groundnut and yig yield of intercrop groundnut. on the other hand, land equivalent ratio (ler) was used for measuring the efficiency of intercropping advantages using the resources of environment compared to monoculture. land equivalent ratio (ler) were calculated by adding the partial ler for each crop and it was calculated by the following formula (mead and willey, 1980) ler= ysg yig yss yis where, yis=yield of intercrop sesame, yss=yield of sole sesame, yig=yield of intercrop groundnut and ysg=yield of sole groundnut pooled analysis was done as because there was no significant difference in yield and yield contributing characters between two years. data were statistically analyzed using analysis of variance technique with the help of computer package mstat-c and mean comparison among the treatments was made by lsd test at 5% level of significance. 102 khan et al. results and discussion yield and yield attributes of sesame: it was observed that the seed yields of sesame significantly influenced intercropping systems but other yield attributes were not insignificant (table 1). the highest seed yield (1.12 t ha-1) was recorded from t2 (sole sesame) which was statistically different with t3 (two rows of groundnut in between paired rows of sesame) and t4 (three rows of groundnut in between two paired rows of sesame). lower seed yield (0.89 t ha-1) was obtained from t3 which was statistically significant with other treatments. higher seed yield of sesame was observed in monoculture compared to intercropping systems might be due to no intercrop competition for light, nutrients, moisture and space. this result corroborates with the findings of uddin et al., (2003). sesame gave 13 to 21 % lower yield in intercropping treatments as compared to their corresponding monoculture, though the plant population of sesame was constant regardless of treatment. the seed yield of sesame was reduced probably due to intercrop competition between sesame and groundnut. however, additional yield from groundnut not only compensated the deficit but also gave extra income. this finding is in conformity with islam et al., (2016). the harvest index (hi) of sesame did not differ by the intercropping systems; it had higher values in t4>t3>t2 (table 1). table1. seed yield, yield attributes and harvest index of sesame under sesame + groundnut intercropping systems in mymensingh, 2015 and 2016 (pooled) treatments plant height (cm) branch plant-1 (no.) capsules plant-1 (no.) 1000 seed wt. (g) seed yield ( t ha-1) harvest index (%) t2 149.0 5.1 86.2 3.2 1.12 37 t3 150.4 5.1 89.8 3.4 0.89 50 t4 151.8 5.0 90.8 3.4 0.97 51 lsd (0.05) ns ns ns ns 0.20 ns cv (%) 5.11 8.73 5.32 7.44 6.42 note:t2=sole sesame, t3=two rows of groundnut in between paired rows of sesame and t4= three rows of groundnut in between paired rows of sesame. yield and yield attributes of groundnut: the variation was found in branches plant-1, kernel plant-1, shelling percent and nut yield hectare while plant height and 100-kernel weight were found insignificant (table 2). the highest nut yield was recorded in t1 (sole groundnut) mainly due to the higher kernel number plant-1, 100-kernel weight and shelling percent of groundnut. the nut yield of groundnut was reduced 23 to 46 % in intercropping system than sole crop of groundnut. this result corroborates with the findings of razzaque et al., (2007) who reported that less groundnut yield was obtained from intercropping system than sole crop due to shading effect of chilli on groundnut. in t4 (three rows of groundnut in between paired rows of sesame) had higher nut yield due to paired rows planting system of sesame fovoured the growth of intercropped groundnut and judicious use of growth resources compared to others. these results are in conformity with the findings of islam et al., (2006). higher harvest index (hi) of groundnut was slightly higher in t4 (three rows of groundnut in between two paired rows of sesame) possibly owing to use of more assimilates to the reproductive organs (table 2). 103 performance of intercropping groundnut with sesame table 2. nut yield, yield attributes and harvest index of groundnut under sesame + groundnut intercropping systems in mymensingh, 2015 and 2016 (pooled) treatments plant height (cm) branch plant-1 (no.) kernel plant-1 (no.) 100kernel wt. (g) shelling (%) nut yield ( t ha-1) harvest index (%) t1 38.2 7.8 17.2 90.2 66.4 1.62 52 t3 35.0 6.8 13.2 88.4 64.4 0.88 48 t4 36.0 6.6 14.2 89.6 66.0 1.25 53 lsd (0.05) ns 1.01 2.14 ns 1.74 0.32 cv (%) 6.77 9.84 9.90 5.32 8.33 7.62 note:-t1=sole groundnut, t3=two rows of groundnut in between two paired rows of sesame and t4= three rows of groundnut in between two paired rows of sesame. equivalent yield and relative yield: all the intercropping systems gave higher sesame and groundnut equivalent yield than that of their corresponding sole crops (table 3). the highest sesame equivalent yield (2.33 t ha-1) as well as groundnut equivalent yield (2.14 t ha-1) were recorded from t4 (three rows of groundnut in between two paired rows of sesame) which covered the yield advantages of 133 and 37 % over their respective sole crops. such yield advantage might be due to combined yield of both the crops. the results are in agreement with the finding of islam et. al., (2016) who reported that highest turmeric equivalent yield was found from turmeric (100 %) + 3 rows of sesame in between turmeric lines. the partial relative yields of intercropped sesame varied from 0.79 to 0.87 and intercropped groundnut ranged from 0.54 to 0.77 (table 3). sesame yield was reduced (13 to 21 %) and groundnut yield reduced (23 to 46 %) among the intercropping system. the yield was reduced due to lower plant population. the result showed that t4 was well accommodative in competitiveness in sesame + groundnut intercropping system (table 3). land equivalent ratio (ler): the land equivalent ratio (ler) was used to assess the performance of an intercrop relative to the corresponding sole crop (mead and willey, 1980). the highest ler value (1.55) was obtained from t4 (three rows of groundnut in between two paired row of sesame) which indicated the superiority of intercropping over monoculture (table 3). it also expressed that by intercropping groundnut with sesame, a farmer can produce 1.25 tons groundnut and 0.97 tons sesame in one hectare of land instead of cultivate those separately as sole crop. table 3. equivalent yields, relative yields and land equivalent ratio of sesame + groundnut combinations in mymensingh, 2015 and 2016 (pooled) treatments sesame equivalent yield (t ha-1) groundnut equivalent yield (t ha-1) partial relative yield (t ha-1) land equivalent ratio (ler) sesame groundnut t1 1.77 1.62 1.00 t2 1.12 1.03 1.00 t3 1.85 1.70 0.79 0.54 1.33 t4 2.33 2.14 0.87 0.77 1.64 note:-t1=sole groundnut, t2=sole sesame, t3=two rows of groundnut in between paired rows of sesame and t4= three rows of groundnut in between paired rows of sesame. 104 khan et al. economic return of intercropping groundnut with sesame: on the basis of two years average result, the highest monetary return (tk. 68,535) was observed in t4 (three rows of groundnut in between two paired rows of sesame) which gave an additional income of tk. 27,300 over sole crop of groundnut and tk. 54,735 over sole crop of sesame (table 4). both intercrop combination gave higher monetary advantages over sole groundnut and sesame. the highest bcr (2.15) was found in t4 (three rows of groundnut in between two paired rows of sesame) over other treatments. these results are in agreement with the findings of islam et al. (2016) who stated that turmeric (100 %) + 3 rows of sesame (100 %) in between turmeric lines intercropping system gave higher additional income and bcr over the sole crop of turmeric. table 4. economics of intercropping sesame with groundnut in mymensingh, 2015 and 2016 (average of two years) treatments gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 97200 55965 41235 1.74 t2 61600 47800 13800 1.29 t3 101750 57390 44360 1.77 t4 128350 59815 68535 2.15 market price: groundnut= tk. 60 kg-1 and sesame= tk. 55 kg-1 conclusion two years average result indicating that intercropping groundnut with sesame gave maximum productivity as well as economic return than monoculture of component crops. the equivalent yields, relative yields, land equivalent ratio (ler) values and economic return were found highest in t4 (three rows of groundnut in between two paired rows of sesame) in groundnut + sesame intercropping system. thus it could be concluded that three rows of groundnut in between paired rows of sesame intercropping system could be adopted for better productivity with maximum profit for the farmers of mymensingh regions instead of sole crops. references ais (agricultural information service). 2017. krishi diary. agril. infor. service, khamarbari, farmgate, dhaka 1216. p 2. alizadeh, y., a. koocheki and m. nassiri mahallati. 2010. yield, yield components and potential weed control of intercropping bean (phaseolus vulgaris l.) with sweet basil (ocimum basilicum l.). iranian j. of field crops res. 7 (2): 541-553. alom, m. s., n. k. paul and m. a. quayyum. 2009. performance of different hybrid maize (zea mays l.) varieties under intercropping systems with groundnut (arachis hypogaea l.). bangladesh j. agril. sci. 34 (4):585-595. awal, m. a., h. koshi and t. ikeda. 2006. radiation interception and use by maize/peanut intercrop canopy. agricultural and forest meteorology. 139: 74-83. bbs (bangladesh bureau of statistics). 2015. year book of agricultural statistics of bangladesh. statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka. p 40. 105 performance of intercropping groundnut with sesame islam, m. n., m. m. haque and a. hamid. 2006. planting arrangement and population density effects on the physiology attributes and productivity of maize-bush bean intercropping system. bangladesh j. agril. res. 31(3):353-364. islam, m. r., m. s. h. molla and m. a. k. mian. 2016. productivity and profitability of intercropping sesame with turmeric at marginal farmers level of bangladesh. saarc j. agri., 14(1): 47-58. jokinen, k. 1991. yield and competition in barley variety mixtures. j. agric. sci. 17 (1):99-102. mead, r. and r. w. willey. 1980. the concept of land equivalent ratio and advantages in yields for intercropping. exp. agric. 16: 217-228. mondal, m. r. i. and m a. wahhab. 2001. production technology of oil crops, oilseed research centre, bangladesh agricultural research institute, joydebpur, gazipur-1701. prasad, k., and r. c. srivastava. 1991. pigeon pea (cajanus cajan) and (glycine max) intercropping system under rainfed situation. indian j. agric. sci. 61: 243-246. razzaque, m. a., s. rafiquzzaman, m. m. bazzaz, m. a. ali and m. m. r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. . bangladesh j. agril. res. 32(1):37-43. santalla, m., a. p. rodino, p. a. casquero and a. m. de ron. 2001. interactions of bush bean intercropped with field and sweet maize. european j. agron. 15: 185-196. uddin, m. s., m. j. rahman, s. a. begum and m. r. ali. 2003. intercropping of maize with soybean in saline area under rainfed condition. . bangladesh j. agril. res. 28(3):451-455. microsoft word 5. baj-285_revised bangladesh agron. j. 2018, 21(1): 51-59 growth and yield performance of foxtail millets under salinity a. nahar1, *, m. a. mannan1, m. a. a. mamun1 and t. k. ghosh2 1department of agronomy and 2department of crop botany bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706. *corresponding author, e-mail: nisu2919@gmail.com (received: 7 december 2017, accepted: 22 february 2018) keywords: coastal area, minor cereal, salt tolerance, stress, yields. abstract crop diversification in saline affected coastal areas is crucial for food security in bangladesh. a pot experiment was conducted at polythene house at bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706 during may to august, 2017 to determine the effect of salt stress on growth and yield performance of foxtail millets. five foxtail millets genotypes viz. (i) bari kaon-1 (check), (ii) bd-878, (iii) bd-897, (iv) bd-891 and (v) bd-881 were tested under three salt stresses viz. (i) control (0 ds/m), (ii) 6 ds/m and (iii) 12 ds/m. completely randomized design (crd) with three replications was followed in the study. the growth parameter viz. stem dry matter, leaf dry matter and root dry matter production of foxtail millets genotypes were significantly varied due to salinity stresses. salinity stresses also significantly influenced yield and yield contributing characteristics of foxtail millets. the genotypes bd-897 and bd-881 produced the higher dry matter, grains per panicle and grain yield per plants under the saline level of 6 ds/m. the higher stress tolerance index of both the genotypes demonstrate that the genotypes bd-897 and bd-881 were more salt tolerant. introduction foxtail millet (setaria italica l.) is one of the world’s most important ancient crops with its domestication in china dating back to 8700 years (liu et al., 2009). it is widely cultivated in asia, europe, north america, australia and north africa for grain or forage (austin, 2006). foxtail millet has attracted international research attention due to its high salinity stress tolerance, low incidence of pest and diseases, high photosynthetic efficiency and nutritional values (liu et al., 2011; vetriventhan et al., 2012). global estimates, dating back two decades, indicate a constant increase in salt affected soils. it has been estimated that worldwide the cultivated area affected by about 23% by salinity and 37% by sodicity (tanji et al., 1990). about 53% of the coastal areas are affected by salinity in bangladesh. it was found that about 10% yield was decreased if the crop was wetted with water of electrical conductivity 1.70 ds/m (evans, 2006). it has become imperative to explore the possibilities of increasing potential of saline affected area for increased production of crops. also, the usual course of salinity increase in intensely irrigated cropping systems and the transient dry land salinity threatens crop production; necessitating identification of both crop species that can tolerate the soil salinity the best and an understanding of the genetic variation within each species for tolerance to saline conditions. foxtail millet (setaria italic l. beauv) is a panicoideae grass that has been reported to have comparable tolerant level to drought (doust et al., 2009) and salinity (kafi et al., 2009), thus it became an important food crop in the arid and semi-arid regions. foxtail millet can be a potential crop for salt affected soils due to its high 52 nahar et al. level of tolerance to salinity (maas, 1985) and the salt ‘escape’ potential due to its short growing duration. there are many sporadic experiments conducted to assess the salinity tolerance of foxtail millets, however, more systematic studies are needed to generate information to improve the productivity of the crops under marginal environment in bangladesh. considering the above facts, this experiment was designed to evaluate the effect of salt stress on growth and yield performance of foxtail millets. materials and methods a pot experiment was conducted at the agronomy research field of bangbandhu sheikh mujibur rahman agricultural university, gazipur-1706 from may to august 2017. the site is located under agro ecological zone28. five foxtail millets genotypes viz. (i) bari kaon-1 (check), (ii) bd-878, (iii) bd-897, (iv) bd-891 and (v) bd-881 were tested under three salt stress viz. (i) control (0 ds/m), (ii) 6 ds/m and (iii) 12 ds/m. the experiment was laid out in a complete randomized design with three replications. the pots used for the experiment having 30 cm length and 24 cm diameter. the pots were filled with soil and cowdung with 2:1 ratio. nitrogen, triple super phosphate, murate of potash and gypsum were applied at the rate of 7028-50-11 kg ha-1 n-p-k-s, respectively (frg, 2012). ten seeds of foxtail millet per pot were sown on 15 january 2017 and the seeds were germinated within 20 january 2017. salt solution was applied at three days interval starting from 15 days after sowing (das) and continued up to 64 das. the crops were harvested at full maturity selecting three plants per pot. data was collected on leaf dry matter, stem dry matter, root dry matter production, grain weight, panicle weight and length and grain yield per plant-1. to record dry matter the partitioned plant parts were dried in an oven at 70oc for 5 days. three plants per pot were harvested at maturity and threshing, cleaning and drying of grain were done separately pot by pot. grain was cleaned and sun dried. stress tolerance index (sti) was calculated using following equation suggested by (fernandez, 1992). sti = ys  yp yp2 where, ys = yield in stress condition, yp = yield in control (non-stress) condition and yp2 = mean yield in control condition. data were analyzed using anova to evaluate treatment effects and the means were separated following least significant difference (lsd) at 5% level of probability (gomez and gomez, 1984). results and discussion dry matter production leaf dry matter, root dry matter and stem dry matter of foxtail millet significantly influenced due to interaction of salinity  genotypes. dry matter accumulation in leaf, root and stem reduced gradually with the increasing of saline concentration. however, the magnitude of reduction is different in different genotypes. genotypes bd-897, bd-891 and bd-881 produced higher amount of leaf root and stem dry matter irrespective of salinity level (table 1). total dry matter production of foxtail millet varied significantly due to interaction of salinity  genotypes. however, the reduction of dry matter was higher in case of salt sensitive var. bari kaon-1 compared to genotype bd-897 and bd-881 (fig. 1). zheng et al. (2008) reported that the chlorophyll content of plant leaf reduced significantly under saline condition. chlorophyll is the most important photosynthetic pigment. due to lacks of this pigment, the production and accumulation of dry matter in leaf, stem and root is hampered in plants. different authors (hasan et al., 2015; khan et al., 2009; ashraf et al., 2005) stated that salinity decreased chlorophyll content of leaf. growth and yield performance of foxtail 53 table 1. dry matter production of foxtail millet genotypes under saline condition genotypes leaf dry matter (g plant-1) root dry matter (g plant-1) stem dry matter (g plant-1) control 6 ds/m 12 ds/m control 6 ds/m 12 ds/m control 6 ds/m 12 ds/m bari kaon-1 2.30 2.23 1.81 0.89 0.55 0.59 3.11 1.75 1.98 bd-878 1.93 2.38 1.82 1.50 0.90 0.68 6.23 3.87 2.85 bd-897 2.46 2.76 2.47 1.44 1.41 1.01 6.48 4.90 3.20 bd-891 2.94 2.27 2.20 1.65 0.82 0.77 5.94 3.60 3.57 bd-881 2.10 2.12 2.29 1.20 1.01 1.07 6.53 4.94 3.60 lsd 0.05 salinity (s) ns 0.29 0.91 genotype (g) ns 0.37 1.16 s  g 0.79 0.65 2.02 cv (%) 21 37.7 29.1 fig. 1. effect of salinity on total dry matter production of foxtail millet genotypes grain yield the interaction effect of salinity  genotypes demonstrated a significant effect on panicle length and panicle weight of foxtail millet (table 2). likewise dry matter production, the panicle length and weight also decreased with the increases of salinity level in all genotypes. the panicle length of bari kaon-1 reduced by 1.7 and 5.68cm in 6 and 12 ds/m, respectively compared to control. however, bd-897 and bd-881 produced panicles of 13.77 and 14.89 cm length in control while 13.11 and 13.78 cm in 6 ds/m; and 11.78 and 13.10 cm in 12 ds/m, respectively. similarly, panicle weight of bari kaon-1 was 1.70 g in control while it was 0.90 and 0.40 g in 6 and 12 ds/m, respectively. on the other hand, bd-897 and bd-881 gave panicles of 1.33g weight in control whereas it was 1.39 and1.02 in 6 ds/m; and 1.00 and 0.84g in 12 ds/m, respectively (table 2). the interaction of salinity  genotypes exerted a significant effect on grain yield of foxtail millets. table 2. panicle length and weight of foxtail millets genotypes under saline condition genotypes panicle length (cm) panicle weight (g panicle-1) control 6 ds/m 12 ds/m control 6 ds/m 12 ds/m bari kaon-1 15.01 13.31 9.33 1.70 0.90 0.40 bd-878 15.97 11.92 11.72 1.26 0.88 0.60 3.0 4.5 6.0 7.5 9.0 10.5 12.0 control 6 ds/m 12 ds/m salinity d ry m at te r p ro du ct io n (g p la nt -1 ) bari kaon-1 bd-878 bd-897 bd-891 bd-881 54 nahar et al. bd-897 13.77 13.11 11.78 1.33 1.39 1.00 bd-891 13.74 12.71 10.33 1.33 1.23 0.63 bd-881 14.89 13.78 13.10 1.17 1.02 0.84 lsd0.05 salinity (s) 1.66 0.21 genotype (g) ns ns s  g 3.72 0.47 cv (%) 27.1 27.2 fig. 2. effect of salinity on grain yield of foxtail millet genotypes the grain yield reduced with the increases of salinity level, but the magnitudes of yield reduction was not same for all foxtail millet genotypes. bari kaon-1 produced the highest yield in control, but lowest under stress condition. bd-897 gave the second highest yield in control but top yielder under both 6 and 12 ds/m salinity (fig. 2). similarly, foxtail millet genotype bd-881 gave satisfactory yield under both 6 and 12 ds/m saline condition. the yield of bd-891 was drastically reduced in 12 ds/m though it was second most top yield under 6 ds/m salinity. bd-878 gave the worst performance in saline condition. grain yield under saline condition reduced due to reduction of dry matter accumulation, shorter and lighter panicle. hasan et al. (2015) stated that the spike per panicle, grains per spike and 1000-grain weight of wheat reduced significantly due to salinity. studies conducted by akram et al. (2000) and kamkar et al. (2004) concluded that yield components of crop severely affected that leads to lower yield of crop in saline condition. however, reduction of photosynthesis, leaf longevity, pollen viability and stigma receptivity are responsible for lower yield under saline condition (khatun and flower, 1995; morad et al., 2003). relationship between grain yield and dry matter production the seed yield of foxtail millets demonstrated a significant linear association with dry matter production (r2 = 0.37**) (fig. 3), panicle length (r2 = 0.36**) (fig. 4), and panicle weight (r2 = 0.86**) (fig. 5). 0.0 0.3 0.6 0.9 1.2 1.5 control 6 ds/m 12 ds/m salinity se ed y ie ld (g p la nt -1 ) bari kaon-1 bd-878 bd-897 bd-891 bd-881 growth and yield performance of foxtail 55 fig. 3. relationship between dry matter production and seed yield of foxtail millets ** = significant at 1% level of probability) fig. 4. relationship between panicle length and seed yield of foxtail millets (** = significant at 1% level of probability) it indicated that the grain yield of foxtail millets increased with increasing dry matter, panicle length and panicle weight. the correlation coefficient (r) indicated that salt tolerance index was related significantly with different yield attributes at 6 ds/m soil salinity (table 3). y = 0.0839x + 0.1043 r2 = 0.37** 0.0 0.4 0.8 1.2 1.6 2.0 0 3 6 9 12 15 dry matter production (g plant-1) se ed y ie ld (g p la nt -1 ) y = 0.0873x 0.3744 r2 = 0.36** 0.0 0.4 0.8 1.2 1.6 2.0 5 8 11 14 17 20 panicle length (cm) se ed y ie ld (g p la nt -1 ) 56 nahar et al. fig. 5. relationship between panicle weight and seed yield of foxtail millets (** = significant at 1% level of probability) table 3. correlation coefficient (r) between salt tolerance index and different yield attributes yield and yield attributes 6 ds/m 12 ds/m panicle length 0.40* 0.001 ns panicle weight 0.30* 0.07 ns dry matter production 0.70** 0.09 ns seed yield 0.26* 0.12ns * and ** indicate significant at 0.05 and 0.01 probability level, respectively. ns = not significant. stress tolerance index (sti)and saline tolerance of foxtail millets genotypes saline tolerance based on dry matter production and grain yield exhibited a wide range of variation among the tested foxtail millets genotypes (figs. 6 and 7). in case of dry matter production, bd-897 demonstrated the highest stress tolerance index (sti) in 6 ds/m saline while bd-881 in 12 ds/m (fig. 7). based on grain yield, bd-897 as well as bd-891 showed the highest sti in 6 ds/m while bd-897 in 12 ds/m (fig. 7). this indicated that salt stress lead to changes in growth, development, and productivity of sensitive millet genotypes and severe stress threaten the plant survival (kafi, 2009). zhi et al. (2004) screened 260 foxtail millet accessions using 1.0 and 1.5% nacl concentration, and concluded that this crop showed a wide range of variation (0 to ~100%) in salt tolerance. y = 0.8126x 0.0917 r2 = 0.86** 0.0 0.4 0.8 1.2 1.6 2.0 0.0 0.5 1.0 1.5 2.0 2.5 panicle weight (g panicle-1) se ed y ie ld (g p la nt -1 ) growth and yield performance of foxtail 57 fig. 6. stress tolerance index (sti) of foxtail millet genotypes based on dry matter production fig. 7. stress tolerance index (sti) of foxtail millet genotypes based on grain yield conclusion the cropping intensity is low in saline affected areas of bangladesh. in this study, it was found that foxtail millets genotypes bd-897 and bd-881 produced higher dry matter and grain yield under 6 ds/m salinity level. however, stress tolerance index of bd-897 and bd-881 were also higher. therefore, it could be concluded that foxtail millets genotypes bd-897 and bd-881 may be cultivated in saline affected (6 ds/m) coastal areas of bangladesh after satisfactory result from on farm trial at farmer’s field at different salinity levels. references 0.0 0.2 0.4 0.6 0.8 1.0 bari kaon-1 bd-878 bd-897 bd-891 bd-881 foxtail millets varieties st i b as ed in d ry m at te r 6 ds/m 12 ds/m 0.0 0.2 0.4 0.6 0.8 1.0 1.2 bari kaon-1 bd-878 bd-897 bd-891 bd-881 foxtail millets varieties st i b as ed o n se ed y ie ld 6 ds/m 12 ds/m 58 nahar et al. akram, m., m. hussain, s. akhtar and e. rasul. 2000. impact of nacl salinity and yield components of some wheat accessions/varieties. int. j. agric. biol. 1: 156-158. ashraf, m. y., k. akhtar, g. sarwar and m. ashraf. 2005. role of rooting system in salt tolerance potential of different guar accessions. agron. sustain. dev. 25: 243-249. austin, d. f. 2006. fox-tail millets (setaria: poaceae) abandoned food in two hemispheres. econ. bot. 60 (2): 143–158. doust, a. n., e. a. kellogg, k. m. devos and j. l. bentsen. 2009. foxtail millet: a sequence-driven grass model system. plant physiol. 149: 137-141. evans, l. 2006. salinity tolerance in irrigated crops. nws department of primary industries. available online at http.//www.dip.nsw.au/arriculture/resources/soils/salinity/crops /tolerance-irrigated. fertilizer recommendation guide (frg). 2012. bangladesh agricultural research council (barc), farmgate, dhaka 1215, pp. 01-265. gomez, k. a., a. a. gomez. 1984. statistical procedure for agricultural research (2nd ed.). john willey and sons, singapore. pp. 28-192. hasan, a., h. r. hafiz, n. siddiqui, m. khatun, r. islam, m. a. a. mamun. 2015. evaluation of wheat genotypes for salt tolerance based on some physiological traits. j. crop sci. biotech. 18 (5): 333 – 340. kafi, m., g. h. zamani and s. g. h. d. ghoraishi. 2009. relative salt tolerance of south khorasan millets. desert 14: 63-70. kamkar, b., m. kafi and a. n. mahallati. 2004. determination of the most sensitive development period of wheat (triticum aestivum) to salt stress to optimize saline water utilization. 4th international crop science congress, iran khaje-hosseini m, powell aa, bingham ij. 2003. the interaction between salinity stress and seed vigour during germination of soybean seeds. seed sci.technol. 31: 715725. khatun, s. and t. j. flowers. 1995. effect of salinity on seed set of rice. plant cell environ. 18: 6167. khan, m. a., m. u. shirazi, m. a. khan, s. m. mujtaba, e. islam, s. mumtaz, a. shereen, r. u. ansari and m. y. ashraf. 2009. role of proline, k/na ratio and chlorophyll content in salt tolerance of wheat (triticum aestivum l.). pak. j. bot. 41: 633-638. liu z, g. bai, d. zhang, c. znu, x. xia, z. cheng and z. shi. 2011. genetic diversity and population structure of elite foxtail millet (setaria italic l. germplasm in china. crop sci. 51: 1655–1663. liu, h., j. zhang, k. b. liu, n. wu, y. li, k. zhou, m. ye, t. zhang, h. zhang, x. yang, l. shen, d. xu and q. li. 2009. earliest domestication of common millet (panicum miliaceum ) in east asia extended to 10,000 years ago. proceedings of the national academy of sciences of the united states of america. 106: 7367-7372. maas, e. v. 1985. crop tolerance to saline sprinkling water. plant soil. 89: 273-284. morad, f., m. i. abdelbagi, b. g. glenn and a. e. james. 2003. salinity tolerance of rice during reproductive development and association with tolerance at the seedling stage. ind. j. plant physiol. special issue 8: 276-287. tanji, k. k. 1990. nature and extent of agricultural salinity. in‘agricultural salinity assessment and management. (eds kk tanji) pp.1-18. american society of civil engineers, new york. vetriventhan, m, h. d. upadhyaya, c. r. anand akumar, s. senthilvel, h. k. parzies, a. bharathi, r. k. varshney and c. l. l. gowda. 2012. assessing genetic diversity, allelic richness and growth and yield performance of foxtail 59 genetic relationship among races in icrisat foxtail millet core collection. plant gene. resour. 10: 214–223. zhen, y., a. jia, t. ning, j. xu, z. li and g. jiang. 2008. potassium nitrate application alleviates sodium chloride stress in winter wheat cultivars differing in salt tolerance. j. plant physiol. 165: 1455-1465. zhi, h., diao, x., lu, p., li, w., akolova, z. 2004. methodology analysis on screening of salt tolerant genotypes from foxtail millet and other setaria species. j. hebei. agr. res. 8: 15-18. microsoft word baj 356c__press bangladesh agron. j. 2020, 23(1): 59-66 evaluation of grain and nutritional quality of transplanted aman rice under different nitrogen levels s. shome1, p.k. biswas1*, m.j. ullah1 and a. barman2 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh; 2soil science division, bangladesh agricultural research institute, gazipur, bangladesh *corresponding e-mail: parimalbiswas@hotmail.com (received: 27 may, 2020, accepted: 25 june, 2020) keywords: rice, milling outturn, protein content, imbibition ratio, gel consistency abstract quality is one of the key characteristics of rice and is largely governed by nitrogen application. an experiment was conducted to scrutinize the effect of nitrogen on quality characteristics of rice, with three nitrogen levels (viz. 50 kg n ha-1, 100 kg n ha-1 and 150 kg n ha-1) and four varieties/lines (viz. sau adl1, brri dhan70, brri hybrid dhan6 and sau adl11). results revealed that quality characters of transplanted aman rice were significantly influenced by nitrogen, variety and their interaction. increasing trend was observed with the increasing level of nitrogen from 50 to 150 kg ha-1 regarding hulling percentage and milling outturn while decreasing trend was observed in case of apparent amylose content and imbibition ratio. maximum protein content (9.60%) and gel consistency (96.16 mm) were recorded at 100 kg n ha-1. among the studied materials, sau adl11 performed better in case of all studied parameters. although interaction of 150 kg n ha-1 with sau adl1 and sau adl11 gave maximum value of hulling percentage and milling outturn. in interaction of 100 kg n ha-1 with these two lines gave maximum protein, gel consistency and satisfactory levels of all quality characters. so, it can be suggested to carry out further investigation with these two rice lines having 100 kg n ha-1. introduction rice is the most important cereal crop and staple food in bangladesh. it is the traditional source of carbohydrate and protein for bangladeshi people. about two-third of total calorie and onehalf of total protein requirement on daily basis of a person is provided by rice (bbs, 2013). among the rice growing countries, bangladesh owns third position in rice area and fourth position in rice production (brri, 2017). traditionally, scientist focalizes to increase yield per unit area to feed the enormous population. but now bangladesh has reached self-sufficiency in case of rice production (kabir, 2015). so, consumer’s favour for better quality rice has been increased. again, people of bangladesh cannot afford other protein sources due to their unavailability and higher cost. so, now it is high time to pay attention to quality rice production to satiate consumer preference and make a stand against famishment. for this, rice genotypes having promising features should be explored. quality of rice is not only hinged on varietal characteristics but also application of nitrogen. nitrogen is the most important element in fertilizer which influenced grain quality mostly eating/cooking quality (da-wei et al., 2017). not only scanty application of nitrogen fetters quality rice production but also excessive nitrogen hampers grain quality (mannan et al., 2009). so, a suitable combination of nitrogen and variety 60 shome et al. is required to improve the quality of rice. although, a number of experiments were done on the effects of nitrogen on quality of rice but comparative study on the performance of rice genotypes with modern inbred and hybrid varieties for different levels of nitrogen is very few in bangladesh. keeping above facts in view, an investigation was done to explore the potentiality of rice genotypes concerning various quality contributing characters of modern inbred and hybrid varieties. materials and methods the present investigation was carried out during aman season of 2017 (julydecember/2017) at the agronomy field of sher-e-bangla agricultural university, dhaka-1207 (23°77′n latitude and 90°33′e longitude). the experiment consisted of three nitrogen levels (viz. 50, 100 and 150 kg n ha-1) and four varieties/lines (viz. sau adl1, brri dhan70, brri hybrid dhan6 and sau adl11). sau adl1 (sau adl: sher-e-bangla agricultural university agronomy department line) and sau adl11 were derived from seeds of a rice line supplied by an ngo, suranjana under various field observations by the agronomy department of sher-e-bangla agricultural university. the experiment was laid out in a split-plot design with three replications. nitrogen was assigned in the main plots and variety/line in the sub-plots. at maturity, the crop was harvested, threshed and winnowed for grain collection. about 500 g grain from each plot was sun dried at about 14% moisture level and stored for grain quality evaluation. grain quality was analyzed at grain quality and nutrition division, bangladesh rice research institute. quality data was recorded as hulling percentage, percentage of milling outturn (mot), protein content, apparent amylose content, alkali spreading value (asv), imbibition ratio and gel consistency. a 100 g grain sample was dehulled in a laboratory huller and the weight of dehusked kernel was recorded. hulling percentage was computed as: hulling percentage = 100 paddyof weight kernel dehuskedof weight × a 200 g rough rice was dehulled in satake rice mill, followed by 45 second polishing in a satake rice grain testing mill tm-05 from which milling outturn (mot) was determined by following equation: milling outturn (%) = 100 rice roughof weight rice milledof weight × standard micro kjeldahl procedure of aoac (1995) was used for the determination of nitrogen and crude protein was estimated by multiplying the nitrogen content by a factor 5.95. apparent amylase content (aac) was determined by the procedure of juliano (1971). alkali spreading value (asv) was determined according to the procedure of little et al. (1958). volumes of cooked and milled rice were measured by water displacement method. five grams of milled rice was placed in a graduated cylinder containing 50 ml of water and the change in volume was noted. five grams of milled rice was cooked and then the cooked rice was placed in the same cylinder and the change in volume was measured. the imbibition ratio (ir) is the ratio of change in the volume of cooked to raw rice (dipti et al., 2002). a rapid, simple test, complementary to the test for amylose content, was developed based on the consistency of a cold 4.4% milled rice paste in 0.2 m koh (cagampang et al., 1972). all the collected data were analyzed following the analysis of variance (anova) technique and using statistix 10 package and the mean differences were adjudged by lsd test (gomez and gomez, 1984). evaluation of grain and nutritional quality of transplanted aman rice 61 results and discussion effect of nitrogen levels nitrogen exhibited significant influence on grain quality of transplanted aman rice (table 1). both hulling percentage and milling outturn were increased with increasing nitrogen levels and reached its maximum at 150 kg n ha-1. but milling outturn at 150 kg n ha-1 was statistically similar with 100 kg n ha-1. gharieb et al. (2016) gave an explanation of such increase that the application of nitrogen increased grain filling rate and consequently decreased the hull thickness. they also explicated the reason of increasing milling outturn with nitrogen levels such that grain metabolic substances were enhanced with increasing nitrogen levels which ultimately enhanced the milling percentage. the lowest protein (8.55%) was obtained from 50 kg n ha-1 but protein obtained from 100 and 150 kg n ha-1 was statistically similar with each other. murthy et al. (2015) also recorded significant effect of nitrogen on protein content. apparent amylose content and imbibition ratio decreased with increasing nitrogen levels. tayefe et al. (2014) opined that aac was decreased with the increase in nitrogen level. dong et al. (2007) delineated the cause that with an increase of nitrogen fertilizer, activation of starch branching enzymes increased and as a result amylopectin percentage increased while in contrast ac decreased. gel consistency increased from 50 to 100 kg n ha-1 then it again lowered down. similar findings were reported by tayefe et al. (2014) who opined that with an increase in the used amount of nitrogen fertilizer to a certain point, an increase in gc and then a lowering trend resulted. nitrogen had no significant influence on alkali spreading value which ranged from 5.38 to 5.28 due to different nitrogen levels. table 1. effect of nitrogen on quality characters of transplanted aman rice nitrogen level hulling percentage milling outturn (%) protein content (%) aac (%) imbibition ratio gel consistency asv n1 72.78 c 68.36 b 8.55 b 24.18 a 4.48 a 88.91 b 5.38 n2 75.44 b 74.03 a 9.60 a 22.29 b 4.35 b 96.19 a 5.28 n3 78.66 a 75.81 a 9.48 a 21.27 c 4.20 c 89.79 b 5.38 lsd(0.05) 2.51 2.08 0.33 0.88 0.03 3.75 ns cv (%) 2.93 2.52 3.15 3.45 0.59 3.61 4.39 n1= 50 kg n ha-1, n2= 100 kg n ha-1, n3= 150 kg n ha-1 aac = apparent amylase content, asv = alkali spreading value effect of variety/line varietal difference had significant impact on grain and nutrition quality of transplanted aman rice (figure 1 & 2). among the tested materials, sau adl11 had the highest hulling percentage (77.74) and brri dhan70 had the lowest (73.12). three variety/line showed milling outturn more than 70% where sau adl1 gave maximum value (75.49%). variation in hulling percentage and milling outturn due to varietal differences was also reported by shozib et al. (2017) and khaled et al. (2014). varieties with higher milling outturn have more shelf life and provide more whiteness that consumer desires (hosen et al., 2017). again, sau adl11 contained about 13 % more protein (9.90 %) than brri hybrid dhan6 and considerably higher amount than other two. (sarker et al., 2014) enunciated genetic make-up as the possible reason for varietal differences regarding grain protein content. all the tested materials contained intermediate amylose content (20-25%). among them sau adl1 contained significantly higher apparent amylose content (24.60%). hosen et al. (2017) and matin et al. (2017) reported 62 shome et al. difference in amylose content among varieties. rice having intermediate aac (20-25%) provides soft and relatively sticky cooked rice (hosen et al., 2017). the highest imbibition ratio (4.47) was obtained from sau adl1 and lowest imbibition ratio (4.10) was obtained from sau adl11. variety with higher imbibition ratio (ir) absorbs more water during cooking and considered as good quality by the lower income people (shozib et al., 2017). the imbibition ratio of brri dhan28 is 4.3 which means 1 kg rice could produce 4.3 kg cooked rice, a mega variety in boro season in bangladesh (shozib et al., 2017). as, sau adl1 had higher ir (4.47) than brri dhan28, so this character may be explored in hyv for mega variety release. again, lower the imbibition ratio, higher will be the energy content per unit volume or weight of cooked rice as they have less water and more solid materials (dipti et al., 2002). so, sau adl11 had more energy content that other tested cultivars. the highest gel consistency (96.32 mm) was observed in sau adl11 followed by brri hybrid dhan6 (92.19 mm). the lowest gel consistency (88.67 mm) was recorded in sau adl1 which was statistically similar with brri dhan70 (89.33 mm). tayefe et al. (2014) also documented the variation in gel consistency due to varietal variation. according to graham (2002), gc 40 mm or less gives very flaky and hard rice, gc 41-60 mm gives medium flaky rice and gc more than 61 mm give soft rice. all the tested materials had gc ranging from 88-97 mm which gave soft cooked rice after cooling. the highest alkali spreading value (7.00) was obtained from brri hybrid dhan6 and the lowest asv was obtained from sau adl1. matin et al. (2017) reported that alkali spreading value was negatively correlated with the cooking time which indicates that cooking time was higher for those varieties which had low alkali spreading value. v1 = sau adl1, v2 = brri dhan70, v3 = brri hybrid dhan6, v4 = sau adl11 fig. 1. effect of variety on (a) hulling percentage (b) milling outturn (c) protein content (d) apparent amylose content of transplanted aman rice (lsd(0.05)= 1.72, 3.04, 0.36 and 1.42, respectively). (a) (b) (c) (d) evaluation of grain and nutritional quality of transplanted aman rice 63 v1 = sau adl1, v2 = brri dhan70, v3 = brri hybrid dhan6, v4 = sau adl11 fig. 2. effect of variety on (e) imbibition ratio (f) gel consistency (g) alkali spreading value of transplanted aman rice (lsd(0.05)= 0.03, 1.54 and 0.22, respectively). interaction effect of nitrogen level and variety significant variation in quality characters of transplanted aman rice was recorded for interaction of nitrogen level and variety/line (table 2). all the studied materials were more responsive to higher nitrogen doses regarding hulling percentage and milling outturn. both of these parameters increased with increasing nitrogen levels among all the varieties. khaled et al. (2014) also found significant effect of nitrogen and variety on hulling percentage but no significant effect on milling percentage. the maximum protein (10.36%) was obtained from sau adl11 fertilized with 100 kg n ha-1 (n2v4) which was statistically similar with n3v4 (10.15 %). lower protein (7.51%) was obtained from brri hybrid dhan6 fertilized with 50 kg n ha-1 (n1v3) which was statistically similar with n1v2 (7.81%). the protein content of brri hybrid dhan6 and brri dhan70 increased with increasing nitrogen levels but protein content of sau adl1 and sau adl11 increased with increasing nitrogen levels from 50 to 100 kg n ha-1 but further increase to 150 kg n ha-1 could not increase protein content. kaur et al. (2016) worked with a rice cultivar pau201 and found that protein content decreased with the increasing nitrogen from 60 to 120 kg n ha-1. zhang et al. (2017) also found such trend of this parameter and concluded 0 1 2 3 4 5 6 7 8 v1 v2 v3 v4 a lk a li s p re a d in g v a lu e variety (e) (f) (g) 64 shome et al. that n rate up to a certain level was sufficient to satisfy n uptake requirement of crop from soil. apparent amylose content and imbibition ratio decreased among all the studied materials with increasing nitrogen levels. da-wei et al. (2017) reported that amylose content decreased among varieties with the increase of nitrogen levels. khaled et al. (2014) and maqsood et al. (2013) also confirmed these results. the maximum gel consistency (97.63 mm) was obtained from sau adl11 fertilized with 100 kg n ha-1 (n2v4) which was statistically similar with n3v4 (97.32 mm), n2v1 (96.00 mm), n2v2 (96.00 mm) and n2v3 (95.11 mm). the lowest gel consistency (80.00 mm) was obtained from n1v1. gel consistency was significantly influenced by interaction effect of nitrogen and variety that was also supported by tayefe et al. (2014) who reported that interaction effect of nitrogen and variety had significant influence on gel consistency. the highest alkali spreading value (7.00) was recorded in brri hybrid dhan6 fertilized with 50, 100 and 150 kg n ha-1. the lowest alkali spreading value (3.50) was obtained from sau adl1 fertilized with 50 kg n ha-1 (n1v1) and brri dhan70 fertilized with 150 kg n ha-1 (n3v2). the interaction of nitrogen and brri hybrid dhan6 had no significant influence on asv but interaction of nitrogen with other studied materials had significant influence. table 2. interaction effect of nitrogen and variety on quality characters of transplanted aman rice interaction hulling percentage milling outturn (%) protein content (%) aac (%) imbibition ratio gel consistency asv n1v1 74.85 cd 67.33 ef 9.50 bcd 25.67 a 4.80 a 80.00 e 3.50 e n1v2 71.31 f 63.67 f 7.81 e 24.84 a 4.80 a 92.00 cd 5.50 c n1v3 72.48 ef 70.27 de 7.51 e 21.85 cd 4.30 c 89.63 d 7.00 a n1v4 72.48 ef 72.15 b-e 9.40 bcd 24.37 ab 4.50 b 94.00 bc 5.50 c n2v1 76.77 bcd 72.79 a-d 9.60 bc 24.00 abc 4.30 c 96.00 ab 4.50 d n2v2 72.28 ef 71.78 cde 9.52 bcd 21.50 d 4.30 c 96.00 ab 4.50 d n2v3 74.63 de 74.89 a-d 8.93 d 21.43 d 4.50 b 95.11 ab 7.00 a n2v4 78.08 bc 76.68 abc 10.36 a 22.23 bcd 4.30 c 97.63 a 5.17 c n3v1 77.40 bcd 75.52 a-d 9.00 cd 24.15 abc 4.30 c 90.00 d 4.50 d n3v2 75.77 cd 72.91 a-d 9.37 bcd 18.86 e 4.30 c 80.00 e 3.50 e n3v3 78.82 b 77.18 ab 9.60 bc 20.58 de 4.2 d 91.83 cd 7.00 a n3v4 82.67 a 77.63 a 9.93 ab 21.49 d 3.50 e 97.32 a 6.50 b lsd(0.05) 2.99 5.27 0.62 2.45 0.06 2.66 0.38 cv (%) 2.30 4.22 3.95 6.33 0.78 1.69 0.92 n1 = 50 kg n ha-1, n2 = 100 kg n ha-1, n3 = 150 kg n ha-1, v1 = sau adl1, v2 = brri dhan70, v3 = brri hybrid dhan6, v4 = sau adl11. conclusion nitrogen had significant impact on grain and nutritional quality of all the tested materials except alkali spreading value. the line sau adl11 gave highest hulling percentage, milling outturn, protein content, gel consistency, lowest imbibition ratio and intermediate amylose content. so, considering nutritive value and quality purpose, sau adl11 has a great potential. again sau adl1 had the highest amylose content and imbibition ratio. the two targeted materials of sau adl1 and sau adl11 performed better with 100 kg nha-1 in case of protein content and eating/cooking quality. but more investigation is suggested to find out a complete management package for this two promising lines. evaluation of grain and nutritional quality of transplanted aman rice 65 acknowledgment authors are immensely grateful to ministry of science and technology, bangladesh for financial support to conduct this research work. authors wish to express their heart felt gratitude to grain quality and nutrition division, bangladesh rice research institute, gazipur, bangladesh for their inestimable help for quality analysis. references aoac. 1995. official methods of analysis. 17th ed., the association of official analytical chemists, gaithersburg, md, usa. bbs. 2013. statistical yearbook of bangladesh. statistics division, ministry of planning, govt. of the people’s republic of bangladesh. pp.89-258. brri. 2017. adhunik dhaner chash. bangladesh rice research institute, joydebpur, dhaka1701. p.1. cagampang, g.b., c.m. perez and b.o. juliano. 1972. a gel consistency test for eating quality of rice. j. sci. food agric. 24: 1589-1594. da-wei, z.h., g.u.o. bao-wei, x.u. ke, d.a.i. qi-gen, w.e.i. hai-yan, g.a.o. hui, h.u. ya-jie, c.u.i. pei-yuan and h.u.o. zhong-yang. 2017. effects of nitrogen level on yield and quality of japonica soft super rice. j. integr. agric. 16(5): 1018-1027. dipti, s.s., s.t. hossain, m.n. bari and k.a. kabir. 2002. physicochemical and cooking properties of some fine rice varieties. pakistan j. nutr. 1(4): 188-190. dong, m., d. sang, p. wang, x. wang and j. yang. 2007. change in cooking and nutrition qualities of grains at different nitrogen levels. rice sci. 14: 141-148. gharieb, a.s., t.f. metwally, s.h. abou-khadrah, a.a. glela and a.e. sabagh. 2016. quality of rice grain is influenced by organic and inorganic sources of nutrients and antioxidant application. cerceta ̆ri agronomice i ̂n moldova. 49(4): 57-68. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. second edn. intl. rice res. inst., john wiley and sons. new york. pp.1-340. graham, r. 2002. a proposal for irri to establish a grain quality and nutrition research center. irri discussion paper series no. 44. los baños (philippines): international rice research institute. p.15. hosen, s., s. jahan, m.m. rahman, m.a. siddiquee and h.b. shozib. 2017. grain quality evaluation & comparative analysis of physicochemical properties of traditional cultivars and high yielding (hyv) aman rice varieties in bangladesh. biol. sci. technol. 5: 1-3. juliano, b.o. 1971. a simplified assay for milled rice amylose. cereal sci. today. 16: 334-360. kabir, m.s., m.u. salam, a. chowdhury, n.m.f. rahman, k.m. iftekharuddaula, m.s. rahman, m.h. rashid, s.s. dipti, a. islam, m.a. latif, a.k.m.s. islam, m.m. hossain, b. nessa, t.h. ansari, m.a. ali and j.k. biswas. 2015. rice vision for bangladesh: 2050 and beyond. bangladesh rice j. 19(2): 1-18. kaur, a., a. ghumman, n. singh, s. kaur, a.s. virdi, g.s. riar and g. mahajan. 2016. effect of different doses of nitrogen on protein profiling, pasting and quality attributes of rice from different cultivars. j. food sci. technol. 53(5): 2452–2462. khaled, m.h., a.e. shaalan, a.m. ahmed and m.a.e. el-dalil. 2014. effect of nitrogen fertilizer sources on grain yield, yield components and grain quality of rice. alexandria sci. exchange j. 35: 304-313. 66 shome et al. little, r.r., g.b. hilder and e.h. dawson. 1958. differential effect of dilute alkali on 25 varieties of milled white rice. cereal chem. 35: 111-126. mannan, m.a., m.s.u. bhuiya, s.m.a. hossain and m.i.m. akhand. 2009. influence of nitrogen on grain qualities of fine rice genotypes in aman and boro seasons. bangladesh j. agril. res. 34(2): 329-333. maqsood, m., m.a. shehzad, s.n.a. ali and m. iqbal. 2013. rice cultures and nitrogen rate effects on yield and quality of rice (oryza sativa l.). turk. j. agric. for. 37: 665-673. matin, a., m.a. siddiqee, s. akther, m.k. alam and m.s. ali. 2017. a comparative study on chemical and cooking properties of abiotic stress tolerant and other high yielding rice varieties in bangladesh. bangladesh j. agril. res. 42(4): 673-679. murthy, k.m.d., a.u. rao, d. vijay and t.v. sridhar. 2015. effect of levels of nitrogen, phosphorus and potassium on performance of rice. indian j. agric. res. 49(1): 83-87. sarkar, s.k., m.a.r. sarkar, n. islam and s.k. paul. 2014. yield and quality of aromatic fine rice as affected by variety and nutrient management. j. bangladesh agric. univ. 12(2): 279–284. shozib, h.b., m.m. hossain, s. jahan, m.s. alam, s.c. das, s. alam, r.b. amin, m.m. hasan, r. malo, m.r. islam, h.u. shekhar and m.a. siddiquee. 2017. study of biochemical and cooking quality traits of major rice varieties of bangladesh. malays. appl. biol. 46(4): 55-62. tayefe, m., a. gerayzade, e. amiri and a.n. zade. 2014. effect of nitrogen on rice yield, yield components and quality parameters. afr. j. biotechnol. 13(1): 91-105. zhang, p., g. ma, c. wang, h. lu, s. li, y. xie, d. ma, y. zhu and t. guo. 2017. effect of irrigation and nitrogen application on grain amino acid composition and protein quality in winter wheat. plos one. 12(6): e0178494. https://doi.org/10.1371/ journal.pone.0178494. bangladesh agron. j. 2023, 26(1): 1-8 study on growth and yield of some aromatic rice varieties t.a. masud1, t.s. roy1, a. rahman1, m.h. mahmud2* and m.d. hossain3 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2project implementation unit-barc, natp-phase-ii project, barc, dhaka-1215, bangladesh 3bangladesh wheat and maize research institute, regional station, jamalpur, bangladesh. *corresponding author, email: h.mahmud193@gmail.com (received: 17 april 2023, accepted: 11 september 2023) keywords: aromatic rice, varietal performance, growth, yield abstract a field experiment was conducted at agronomy field of sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka during the period from june to december 2017 with seventeen aromatic rice varieties viz., v1= chiniatap 1, v2= chiniatap 2, v3= kataribhog 1, v4= kataribhog 2, v5= brri dhan34, v6= brri dhan37, v7= brri dhan38, v8= br5/dulabhog, v9= khoisanne, v10 = sadasanne, v11= zirabhog, v12= begun bichi, v13= shakkhorkhora, v14= chinigura, v15= kalijira, v16= badshabhog, v17= modhumala to study on growth and yield of some aromatic rice varieties. the experiment was laid out in a randomized complete block design (rcbd) with three replications. regarding growth and yield parameters, the highest number of total tillers hill−1 (23.33), leaf area index (5.38), flag leaf length (30.12 cm), number of effective tillers hill−1 (21.67), panicle length (32.00 cm), number of grains panicle−1 (230.3), number of filled grains panicle−1 (212.7), grain yield (3.42 t ha−1), straw yield (6.19 t ha−1) and number of biological yield (9.610 t ha−1) were found in var. brri dhan37 but the highest 1000grains weight (22.80 g) and harvest index (37.48%) were found modhumala followed by brri dhan34, respectively. the lowest number of effective tillers hill−1 (13.33), panicle length (24.67 cm), grain yield (1.583 t ha−1), straw yield (4.083 t ha−1), biological yield (5.667 t ha−1) and harvest index (27.89%) were found in the var. modhumala. introduction rice (oryza sativa l.) is the most important food crop in bangladesh where 75.01% of total cropped area is used for rice production, with an annual production of 37.60 million tons from 11.70 million hectares of land (bbs, 2021). most of the aromatic rice varieties in bangladesh are of traditional type, photoperiod sensitive and are grown during aman season in the rain-fed low land ecosystem (baqui and das, 2000). in northern districts of bangladesh, 30% of the rice lands were covered by aromatic rice cultivars during aman season (islam et al., 2012). in respect of production of aromatic rice, dinajpur, naogaon, chittagong and sherpur had 1st, 2nd, 3rd and 4th position respectively in 2002-03 (talukder et al., 2004). aromatic rice varieties are rated best in quality and fetch much higher price in the international market. the yield of rice depends on its different growth parameters i.e. leaf area index, dry matter production and its partitioning, tillering, etc (idris and matin, 1990). again, the yield of rice also depends on leaf area duration (lad), crop growth rate (yusuf, 1997). aromatic rice is the most highly valued rice commodity in bangladesh agricultural trade markets having small grain and pleasant aroma with soft texture upon cooking (dutta et al., 1998). however, the price of fine rice, especially the aromatic rice is 2-3 times higher than that of coarse rice (biswas et al., 1992). though its yield is low, but it requires less input compared to coarse rice. 2 masud et al. but research works on local aromatic rice genotypes is limited in bangladesh in relation to their yield and grain quality characteristics. as such, research work has been undertaken in order to study the yield performance of aromatic rice varieties. materials and methods the experiment was conducted at the experimental field of sher-e-bangla agricultural university, dhaka under the agro-ecological zone of modhupur tract, aez-28 during the period from july 2017 to december 2017. the experimental area is under the sub-tropical climate that is characterized by high temperature, high humidity, and heavy rainfall with occasional gusty winds in kharif season (april-september) and less rainfall associated with moderately low temperature during the rabi season (october-march). the experiment was laid out in a randomized complete block design (rcbd) with three replications. the treatments (varieties) were as follows: 1) v1 = chiniatap 1, 2) v2= chiniatap 2, 3) v3= kataribhog 1, 4) v4= kataribhog 2, 5) v5 = brri dhan34, 6) v6 = brri dhan37, 7) v7 = brri dhan38, 8) v8 = br5 (dulabhog), 9) v9 = khoisanne, 10), v10= sadasanne, 11) v11= zirabhog, 12) v12 = begun bichi, 13) v13 = shakkhorkhora, 14) v14 =chinigura, 15) v15 = kalijira, 16) v16 = badshabhog, 17) v17 =modhumala. the seeds of local varieties were collected from brri, joydebpur, gazipur, bangladesh and personal collection. seeds were sown in seedbed to transplant the seedlings in the main field. the plot selected for the experiment was opened in the last week of july 2017. weeds and stubble were removed and finally obtained a desirable field for transplanting of the seedlings. fertilizers and manure were applied for the cultivation of crops as recommended by brri, 2016. uprooted seedlings were transplanted in the main field with a spacing 20 cm from row to row and 15 cm from hill to hill. all intercultural operations like gap filling, weeding, plant protection, irrigation and drainage were taken properly. the rice plant was harvested depending upon the maturity of the plant.the grains were cleaned and finally the weight was adjusted to a moisture content of 12%. the height of the plant was recorded in centimeters (cm) at the time of 25, 50, 75 date after transplanting (dat) and at harvest. number of leaves hill−1, leaf area index (lai), number of effective tillers hill−1, number of non-effective tillers hill−1, number of total tiller−1, number of filled, unfilled grains, number of total grains, panicle length (cm), sterile percentage, weight of 1000 grains (g) was counted. grain and straw obtained from each unit plot were sun-dried and weighed carefully. the biological yield was calculated with the following formula: hi = economic yield (grain weight) × 100 biological yield (total dry weight) the data were analyzed, and the means were separated by lsd at 5% level of significance using the statistical computer package program mstat-c. results and discussion plant height plant height of different aromatic rice varieties at different days after transplanting showed statistically significant difference (table 1). plant height was increased progressively with the advancement of time and growth stages. at vegetative stage, 25 dat, among the varieties, the highest (54.47 cm) plant height was observed in the var. modhumala. on the other hand, the lower (38.4 cm) plant height was observed in shakkhorkhora which was statistically similar to the var. brri dhan34. at 50 dat, among the varieties the highest (105.8 cm) plant height was growth and yield of aromatic rice varieties 3 observed in modhumala while lowest (76.20 cm) in var. brri dhan34. at the reproductive phase (75 dat), the highest plant height was achieved from modhumala (139.2 cm) and the lower t plant height was recorded in chinigura (112.1 cm) followed by kataribhog 1 (112.6 cm), badshabhog (112.6 cm), brri dhan38 (113.2 cm) and khoisanne (113.3 cm). r. at harvest, among the varieties the maximum (162.8 cm) plant height was observed in the var., badshabhog which was statistically same with modhumala. on the other hand, the lowest (137.3 cm) plant height was observed in the var. khoisanne followed by h chiniatap 2. similar results were also reported by sinha et al. (2009), sarker et al. (2013) and anwar and begum (2010), also found that plant height varied significantly among the varieties after transplanting which increased up to maturity. number of leaves hill−1 significant difference on total number of leaves hill−1 in the rice varieties was observed from vegetative (25 dat) to reproductive (75 dat) stage (table 1). table 1. plant height and number of leaves hill−1 of 17 aromatic rice varieties plant height (cm) number of leaves hill−1 25 dat 50 dat 75 dat harvest 25 dat 50 dat 75 dat harvest v1 48.33 b 84.67 e 114.3 fg 154.5 de 22.90 ef 53.77 g 57.03 e 54.37 d v2 40.33 gh 87.33 cd 129.5 b 153.7 de 27.83 a 70.57 a 69.09 a 65.26 a v3 40.83 g 81.27 g 112.6 h 138.1 g 22.80 efg 67.38 b 62.57 bc 59.66 b v4 47.33 bc 88.23 c 127.5 c 149.5 f 22.74 efg 60.01 d 56.92 e 53.09 f v5 39.00 hi 76.20 i 114.3 fg 156.3 cd 22.64 efg 66.99 b 62.33 cd 59.30 b v6 48.73 b 88.50 c 114.8 f 152.3 e 26.75 b 63.69 c 57.95 e 54.04 de v7 48.50 b 84.77 e 113.2 gh 154.1 de 27.43 ab 60.67 d 61.57 cd 57.82 c v8 40.67 g 79.00 h 115.3 f 152.8 e 24.10 d 64.03 c 61.19 d 57.49 c v9 43.33 f 80.83 g 113.3 gh 137.3 g 21.50 h 60.01 d 62.21 cd 58.03 c v10 43.67 f 80.67 g 114.4 fg 155.7 cd 23.34 de 60.75 d 57.81 e 53.54 ef v11 46.43 cd 82.63 f 114.0 fg 157.8 bc 25.00 c 59.10 de 52.02 g 48.36 h v12 44.33 ef 81.83 fg 114.2 fg 157.8 bc 23.20 ef 56.90 f 53.99 f 51.09 g v13 38.40 i 91.67 b 126.1 d 159.9 b 20.33 i 57.34 ef 54.53 f 50.78 g v14 45.67 de 84.67 e 112.1 h 159.9 b 22.43 fg 53.78 g 63.81 b 59.35 b v15 48.47 b 90.50 b 123.6 e 157.5 bc 22.03 gh 52.47 g 62.10 cd 59.76 b v16 45.33 de 86.33 d 112.6 h 162.8 a 21.35 h 49.33 h 52.20 g 48.37 h v17 54.47 a 105.8 a 139.2 a 162.7 a 25.50 c 52.00 g 41.00 h 37.25 i lsd0.05 1.43 1.20 1.33 2.69 0.80 1.89 1.34 0.83 cv (%) 6.91 7.85 8.68 10.87 6.70 8.92 7.38 06.96 values followed by same letter(s) did not differ significantly at 5% level of probability v1 = chiniatap 1, v2 = chiniatap 2, v3 = kataribhog 1, v4 = kataribhog 2, v5 = brri dhan34, v6 = brri dhan37, v7 = brri dhan38, v8 = br5 dulabhog, v9 = khoisanne, v10 = sadasanne, v11 = zirabhog, v12 = begun bichi, v13 = shakkhorkhora, v14 = chinigura, v15 = kalijira, v16 = badshabhog, v17 = modhumala the total number of leaves was continued to increase up to 75 dat and thereafter declined. for 25 dat, among the varieties tested, the maximum number of leaves hill−1 was recorded in chiniatap 2 (27.83) followed by brri dhan38 (27.43) while the lowest number of leaves hill−1 was recorded in shakkhorkhora (20.33). for 50 dat, the highest number of leaves hill−1 was recorded in chiniatap 2 (70.57) while lowest number of leaves hill−1 was recorded in badshabhog (43.33). for 75 dat, the highest number of leaves hill−1 was recorded in chiniatap 2 (69.09) and the lowest number of leaves hill-1 in modhumala (41.00).. at maturity, the highest 4 masud et al. number of leaves hill−1 was recorded in chiniatap 2 (65.26) and the lowest number of leaves hill−1 was recorded in modhumala (37.25) similar results also reported by haque et al. (2013), sarker et al. (2013) where the leaf number varied among rice cultivars. number of tillers hill−1 the number of tillers plant−1 of different aromatic rice varieties on different days after transplanting showed a significant difference (table 2). at 25 dat, the highest number of tillers hill-1 was produced by brri dhan37 (9.94) while a lower number of tillers hill−1 was found in modhumala (6.26) followed by sadasanne (6.54) and begun bichi (6.49). at 50 dat, the maximum number of tillers hill−1 was produced by brri dhan37 (16.59) followed by chiniatap 2 (16.03) and brri dhan38 (15.72). the lowest number of tillers hill−1 was found in modhumala (9.81) which was significantly different from the rest of the varieties. at 75 dat, the maximum t number of tillers hill−1 was found in br5/dulabhog (23.00) which was at par brri dhan38 (22.75), brri dhan34 (22.51), and chiniatap 2 (21.96). the lowest number of tillers hill−1 was found in modhumala (14.87) which was significantly different from the rest of the variety. at maturity, the highest number of tillers hill−1 was produced by brri dhan37 (23.33) and the lowest number of tillers hill−1 was found in modhumala (13.33). this result was also supported by zahid et al. (2005). chandra et al. (2021) hossain et al. (2008), obaidullah et al. (2009) and chowdhury et al. (2005) also reported that the highest number of fertile tillers per hill was obtained in brri dhan37. table 2. number of tillers hill−1 and leaf area index (lai) of 17 aromatic rice varieties treatment number of tillers hill−1 leaf area index (lai) 25 dat 50 dat 75 dat harvest 25 dat 50 dat 75 dat v1 6.81 fg 13.63d 17.63 f 17.67 de 0.76 4.56e 4.36 e v2 7.10 f 16.03 ab 21.96 abc 18.00 cd 0.73 4.20 f 4.10 f v3 7.90 cd 12.91 d 21.35 bcd 16.67 efg 0.60 3.55 h 3.43 h v4 7.08 f 13.79 d 20.17 de 17.33 def 0.53 3.47 h 3.34 h v5 7.50 e 15.01 bc 22.51 ab 19.00 bc 1.00 5.32 abc 5.11 bc v6 9.94 a 16.59 a 20.16 de 23.33 a 1.07 5.56 a 5.38 a v7 8.78 b 15.72 ab 22.75 ab 19.00 bc 0.95 5.44 ab 5.30 ab v8 7.66 de 15.33 b 23.00 a 19.67 b 0.99 5.23 bc 5.01 c v9 6.76 fg 13.53 d 20.30 de 17.67 de 0.63 3.55 h 3.38 h v10 6.54 gh 13.10 d 19.65 e 15.33 hi 0.73 4.15 f 4.01 f v11 8.67 b 13.88 cd 19.83 de 15.67 ghi 0.84 4.55 e 4.37 e v12 6.49 gh 13.00 d 19.50 e 16.33 fgh 0.61 3.70 gh 3.47 gh v13 7.93 cd 13.40 d 19.20 e 16.67 efg 0.64 3.85 g 3.66 g v14 6.64 g 13.32 d 19.73 e 16.67 efg 0.74 4.19 f 3.99 f v15 7.68 de 14.00 cd 17.46 f 17.33 def 0.91 5.13 cd 4.92 cd v16 8.13 c 13.18 d 20.75 cde 14.67 i 0.84 4.93 d 4.75 d v17 6.26 h 9.80 e 14.87 g 13.33 j 0.42 3.12 i 3.02 i lsd0.05 0.35 1.190 1.554 1.251 ns 0.26 0.19 cv (%) 7.74 8.97 9.05 8.35 3.65 9.55 8.49 values followed by same letter(s) did not differ significantly at 5% level of probability. v1 = chiniatap 1, v2 = chiniatap 2, v3 = kataribhog 1, v4 = kataribhog 2, v5 = brri dhan34, v6 = brri dhan37, v7 = brri dhan38, v8 = br5 dulabhog, v9 = khoisanne, v10 = sadasanne, v11 = zirabhog, v12 = begun bichi, v13 = shakkhorkhora, v14 = chinigura, v15 = kalijira, v16 = badshabhog, v17 = modhumala growth and yield of aromatic rice varieties 5 leaf area index leaf area index of different aromatic rice varieties at different days after transplanting showed significant difference from 55 dat to 80 dat but at 25 dat, all the aromatic rice varieties showed non-significant difference. at 50 dat, among the varieties the maximum (5.56) leaf area index was observed in the var. brri dhan37followed by the var. brri dhan34 and brri dhan38. on the other hand, the lowest (3.12) leaf area index was observed in the var. modhumala. at 75 dat, among the varieties the maximum (5.38) leaf area index was observed in the var. brri dhan37 which was followed by the var. brri while the lowest (3.02) leaf area index was observed in the var. modhumala. shahidullah et al. (2009) who stated that different aromatic rice genotypes exhibited significant variations for leaf area index (lai). number of non-effective tiller hill−1 number of ineffective tiller hill-1 of different aromatic rice varieties showed nonsignificant difference (table 3). table 3. number of non-effective tillers hill−1, number of effective tillers hill−1, length of panicle (cm), number of total grains panicle−1, filled grains panicle−1 and unfilled grains panicle−1 of aromatic rice varieties. treatment number of noneffective tillers hill−1 number of effective tillers hill−1 length of panicle (cm) number of filled grain's panicle−1 number of unfilled grain's panicle−1 v1 0.33 17.33cd 31.33 b 121.3h 18.33 f v2 0.67 17.33 cd 30.67 c 151.7 e 21.67 e v3 0.33 16.33 de 29.00 ef 98.33 j 32.33 c v4 1.00 16.33 de 29.00 ef 75.67 k 31.67 c v5 0.67 18.33 bc 26.33 h 144.3 f 35.67 b v6 1.66 21.67 a 32.00 a 212.7 a 17.67 fg v7 0.67 18.33 bc 31.00 bc 183.3 b 44.67 a v8 1.00 18.67 b 21.00 k 162.3 d 28.00 d v9 0.33 17.33 cd 25.33 i 121.0 h 19.33 ef v10 0.33 15.00 fg 25.67 i 128.0 g 17.33 fg v11 0.33 15.33 efg 27.67 g 169.7 c 28.00 d v12 0.33 16.00 ef 28.67 f 126.0 gh 17.33 fg v13 0.33 16.33 de 29.33 e 153.0 e 13.33 h v14 0.33 16.33 de 27.33 g 109.0 i 18.00 fg v15 1.00 16.33 de 30.00 d 131.3 g 9.00 i v16 0.33 14.33 g 26.67 h 143.3 f 27.67 d v17 0.67 12.67 h 24.67 j 93.33 j 15.67 gh lsd0.05 ns 1.20 0.60 5.47 2.50 cv (%) 111.08 10.33 8.34 10.8 6 8.77 values followed by same letter(s) did not differ significantly at 5% level of probability v1 = chiniatap 1, v2 = chiniatap 2, v3 = kataribhog 1, v4 = kataribhog 2, v5 = brri dhan34, v6 = brri dhan37, v7 = brri dhan38, v8 = br5 dulabhog, v9 = khoisanne, v10 = sadasanne, v11 = zirabhog, v12 = begun bichi, v13 = shakkhorkhora, v14 = chinigura, v15 = kalijira, v16 = badshabhog, v17 = modhumala number of effective tiller hill−1 number of effective tiller hill−1 of different aromatic rice varieties showed significant difference (table 3). among the varieties, the highest (21.67) number of effective tiller found in the var. brri while the lowest (12.67) var. modhumala. similar results were also reported by jisan et al. (2014) and yang et al. (2001). 6 masud et al. panicle length panicle length (cm) of different aromatic rice varieties showed statistically significant difference (table 3). among the varieties, the highest (32.00 cm) panicle length was found in the var. brri dhan37 and the lowest (24.67) number in the var. modhumala. similar results were also observed by anwar and begum (2010), abou-khalif (2009), ashrafuzzaman et al. (2009), and sarkar et al. (2014). number of filled grains panicle−1 different varieties of aman rice showed significant variation on number of filled grains panicle−1 (table 3). the highest number of filled grains panicle−1 (212.7) was observed from in var. brri dhan37 and the lowest in var. kataribhog 2. similar result were also observed by kusutani et al. (2000) and chowdhury et al. (2005). number of unfilled grains panicle−1 number of unfilled grains panicle-1 was significantly varied (table 3). the highest number of unfilled grains panicle−1 (44.67) was observed from the var. brri dhan38 and the lowest in the var. kalijira. similar result was also observed by chowdhury et al. (2005). sterility percentage sterility percentage of different aromatic rice varieties showed significant difference (table 4). among the varieties, the highest sterility percentage (24.29%) was found in the var. katari bhog1 and the lowest (6.38%) in the var. kaligira which was at par to var. brri dhan37 weight of 1000-grains weight of 1000-grains (g) of different aromatic rice varieties showed significant difference (table 4). among the varieties, the highest (22.80 g) 1000-grains weight (g) was found in the var. modhumala and the lowest (9.11 g) in the var. sadasanne. similar results were also observed by murshida et al. (2017) and sarkar et al. (2014). grain yield different varieties of rice had significant influence on grain yield (table 4). in was noted that the highest grain yield (3.42 t ha−1) was observed from the var. brri dhan37 whilethe lowest grain yield (1.58 t ha−1) from the var. modhumala which was followe by kataribhog2. similar result was also observed by haque et al. (2013), murshida et al. (2017), and sarker et al. (2013). straw yield straw yield of different aromatic rice varieties showed significant difference (table 4). among the varieties, the highest (6.19 t ha−1) straw yielwas found in the var. brri dhan37 and the lowest (4.08 t ha−1) in the var. modhumala. similar result was also observed by chowdhury et al. (2005). biological yield biological yield of different aromatic rice varieties showed significant difference (table 4). among the varieties, the highest (9.61 t ha−1) biological yield was found in the var. brri dhan37 and the lowest (5.67 t ha−1) in modhumala. similar results were also observed by chowdhury et al. (1995). they showed that grain yield was positively correlated with biological yield in rice. growth and yield of aromatic rice varieties 7 harvest index harvest index (%) of different aromatic rice varieties showed significant difference (table 4). among the varieties, the highest (37.48) harvest index was found in the var. brri dhan34 and the lowest (27.89) in the var. modhumala which was at par with kataribhog1 and kataribhog2. similar results were also observed by ashrafuzzaman et al. (2009), and bhowmick and nayak (2000). table 4. yield and yield parameters of aromatic rice varieties treatment sterility percentage (%) weight of 1000-grains (g) grain yield (t ha−1) straw yield (t ha−1) biological yield (t ha−1) harvest index (%) v1 13.11 fgh 14.95de 2.43f 4.94ef 7.37 e 32.87d v2 12.49 gh 12.07 gh 2.22 g 4.91 ef 7.14 fg 31.17 e v3 24.98 a 13.57 f 1.90 h 4.77 fg 6.67 i 28.50 gh v4 23.48 b 13.72 f 1.69 i 4.29 i 5.99 j 28.23 gh v5 19.79 c 10.39 i 3.03 b 5.14 d 8.10 c 37.48 a v6 7.647 ij 15.64 d 3.42 a 6.19a 9.61 a 35.58 b v7 19.55 c 17.18 c 2.96 bc 5.573bc 8.54 b 34.72 bc v8 14.87 de 11.23 hi 2.33 fg 4.783fg 7.12 fg 32.77 d v9 13.74 efg 20.08 b 2.30 fg 4.523h 6.82 hi 33.76 cd v10 11.92 h 9.110 j 2.41 f 4.80 fg 7.21 ef 33.48 cd v11 14.12 ef 11.11 hi 2.66 e 5.04 de 7.68 d 34.54 bc v12 11.99 h 10.57 i 2.37 fg 4.57 h 6.94 gh 34.23 bcd v13 7.977 i 14.02 ef 2.02 h 4.65 gh 6.67 i 30.32 ef v14 14.05 ef 11.93 gh 2.04 h 4.87 ef 6.91 h 29.48 fg v15 6.38 j 12.91 fg 2.85 cd 5.62 b 8.47 b 33.66 cd v16 16.12 d 10.98 hi 2.70 de 5.40 c 7.95 c 33.97 cd v17 14.29 ef 22.80 a 1.58 i 4.08 j 5.67 k 27.89 h lsd(0.05) 1.34 1.23 0.17 0.17 0.19 1.57 cv (%) 7.88 9.10 6.90 6.37 8.35 9.91 values followed by same letter(s) did not differ significantly at 5% level of probability v1 = chiniatap 1, v2 = chiniatap 2, v3 = kataribhog 1, v4 = kataribhog 2, v5 = brri dhan34, v6 = brri dhan37, v7 = brri dhan38, v8 = br5 dulabhog, v9 = khoisanne, v10 = sadasanne, v11 = zirabhog, v12 = begun bichi, v13 = shakkhorkhora, v14 = chinigura, v15 = kalijira, v16 = badshabhog, v17 = modhumala references abou-khalif, a.a.b. 2009. evaluation of some hybrid rice varieties in under different sowing times. african. j. plant sci. 3(4): 53-58. anwar, m.p. and m. begum. 2010. tolerance of hybrid rice variety sonarbangla-1 to tiller seperation. bangladesh j. crop sci. 13(15): 39-44. ashrafuzzaman, m., m.r. islam, m.r. ismail, s.m. shahidullah and m.m. hanafi. 2009. evaluation of six aromatic rice varieties for yield and yield contributing characters. intl. j. agric. biol. 11: 616–620. baqui, m.a. and t. das. 2000. aromatic rices of bangladesh. in: aromatic rices, r.k. singh, u.s. singh, and g.s. khush (eds.). oxford & ibh publishing co. pvt. ltd., new delhi and calcutta, india. pp. 184-187. bbs. 2021. bangladesh bureau of statistics. statistical pocketbook of bangladesh. ministry of planning, government of the people’s republic of bangladesh. pp.132. bhowmick, n. and r.l. nayak. 2000. response of hybrid rice (oryza sativa l.) varieties to nitrogen, phosphorus and potassium fertilizers during dry (boro) season in west bengal. indian j. agron. 45(2): 323-326. biswas, s.k., b. banu, k.a. kabir, f. begum and n.h. choudhury. 1992. physicochemical properties of modern and local rice varieties of bangladesh. bangladesh rice j. 3: 128-131. 8 masud et al. brri. 2007. bangladesh rice research institute. adunik dhaner chash (in bengali). 14th edn. bangladesh rice research institute, joydebpur, gazipur, bangladesh. pp. 17-30. chandra, b., t. reddy, n. ansari and s. sudheer. 2021. correlation and path analysis for yield and yield components in rice (oryza sativa l.). agric. sci. digest. 29(1): 45-47. chowdhury, s.a., m.a. majid, k.s. hoque, m. islam and m.m. rahman. 1995. effect of variety on yield and nutritive value of rice straw. asian j. anim. sci. 8(4): 329-335. chowdhury, u.m.j., u.a. sacker, r.m.a. sarkar and m.a. kashem. 2005. effect of variety and number of seedlings hill's on the yield and its components on late transplanted aman rice. bangladesh j. agric. sci. 20(2): 311-316. dutta, r.k., b.p. lahiri and m.a.d. mia. 1998. characterization of some aromatic rice cultivars in relation to their physio-chemical quality of grains. indian j. plant physiol. 3(1): 61-64. haque, m.m., h.r. pramanik and j.k. biswas. 2013. physiological behavior and yield performances of hybrid rice at different planting dates in aus season. bangladesh rice j. 17: 7-14. hossain, m.f., m.s. islam, m.m. rahman, m.o. faruk and m.g. ershad. 2008. yield and quality performance of some aromatic rice varieties of bangladesh. j. agrofor. environ. 2(2): 155-158. idris, m. and m. matin. 1990. response of four exotic strains of aman rice to urea. bangladesh j. agril. sci. 17(2): 271-275. islam, m.s., m.a.r. sarkar, s. uddin and s. parvin. 2012. yield of fine rice varieties as influenced by integrated management of poultry manure, urea super granules and prilled urea. j. environ. sci. natu. res. 5(1): 129-132. jisan, m.t., s.k. paul and m. salim. 2014. yield performance of some transplant aman rice varieties as influenced by different levels of nitrogen. j. bangladesh agric. univ. 12(2): 321–324. kusutani, a., m. tovata, k. asanuma and j. cui. 2000. studies on the varietal differences of harvest index and morphological characteristics of rice. japanese j. crop sci. 69: 359–364. murshida, s., m.r. uddin, m.p. anwar, u.k. sarker, m.m. islam and m.m.i. haque. 2017. effect of variety and water management on the growth and yield of boro rice. progress. agric. 28(1): 26-35. obaidullah, m., p.k. biswas and a.k.m.r. amin. 2009. influence of clonal tiller age on growth and yield of aman rice varieties. j. sher-ebangla agric. univ. 3(1): 35-39. sarkar, n.a.r., m.s. siddique and m.s. islam. 2013. effect of variety and structural arrangement of rows on the yield and yield components of transplant boro rice. bangladesh j. agric. sci. 19(3): 43-51. sarkar, s.k., m.a.r. sarkar, n. islam and s.k. paul. 2014. yield and quality of aromatic fine rice as affected by variety and nutrient management. j. bangladesh agril. univ. 12(2): 279–284. shahidullah, s.m., m.m. hanafi, m. ashrafuzzaman, m.r. ismail and m.a. salam. 2009. phenological characters and genetic divergence in aromatic rice. afr. j. biotechnol. 8(14): 3199-3207. sinha, a.c., p. kairi, p.s. patra and b. de. 2009. performance of aromatic rice varieties under terai region of west bengal. j. crop sci. weed. 5(1): 285-287. talukder, r.k., a.h. sarker and a. aziz. 2004. potential of exporting aromatic and fine quality rice from bangladesh. final report, bangladesh rice foundation. yang, f., x.l. wang, j.y. ma and f.l. ling. 2001. a comparative analysis of yield component factors of two rice varieties of jnd and jnd 13. j. jilin agril. univ. 23(4): 21-24. yusuf, h.k.m. 1997. report of the sustainable food security mission in bangladesh. fao, rome. zahid a.m., m. akhtar, m. anwar and j. adil. 2005. genotypic and phenotypic correlation. and path analysis in coarse grain rice. proc. int. sem. rice crop, october 2-3. rice research institute, kala shah kau, pakistan. bangladesh agron. j. 2021, 24(1): 25-36 growth and yield of cowpea as influenced by different phosphorus levels f.b. putul1, a.r. khan1, m.s. hossain1, a. mahmud1, q.a. khaliq1 and t. ahmed2 1department of agronomy and 2department of agroforestry and environment, bangabandhu sheikh mujibur rahman agricultural university, gazipur1706, bangladesh. corresponding email: arif@bsmrau.edu.bd (received: 15 january 2021, accepted: 20 april 2021) keywords: legume, triple super phosphate, absolute growth rate, quality abstract the experiment was carried out at the research field of the department of agronomy of bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur during december 2016 to april 2017 to investigate the effect of different phosphorus levels (0, 30, 60 and 90 kg p ha-1) on the growth and yield of four selected cowpea genotypes (bari felon-1, a-06008, vi046192 and vi034386). the experiment was laid out in a factorial randomized complete block design with three replications. the results indicated that, among the genotype, bari felon-1 required minimum days to 1st (96 das) and 50% flowering (108 das) showing the highest absolute growth rate (0.71 g day-1), crop growth rate (23.69 g m-2 day-1), relative growth rate (0.047 g g-1 day-1), net assimilation rate (1.40 g m-2 day-1), leaf area index (6.68), spad value (51.03), seed length (0.71 cm) and breadth (0.54 cm). but the genotype, a-06008 gave the highest grain yield (0.62 t ha-1). application of phosphorus at 90 kg ha-1 showed the highest leaf area index (6.67), spad value (50.98), pod length (14.33 cm), seed length (0.70 cm), seed breadth (0.50 cm) and grain yield (0.34 t ha-1). in terms of growth and yield, the cowpea genotype a-06008 showed the best performance at the phosphorus level of 90 kg ha-1. introduction cowpea (vigna unguiculata l. walp) is an important legume-pulse crop grown around the world which serves food for human consumption and fodder for livestock (mfeka et al., 2019). the ripe seed on an average contains 22% protein, 1.4% fat, 59.1% carbohydrate, and 3.7% ash. the energy value is 340 kcal/ 100 g. cowpea is suitable to grow at all regions of bangladesh and grown as a short-duration crop in the rice based cropping systems after the harvest of transplant aman rice (william, 2016). cowpea production is lower which is mainly due to the poor agronomic management as adopted to its production. although cowpea is known to obtain most of its nitrogen requirements through symbiotic fixation, cowpea requires more phosphorus (p) than nitrogen (fao, 2005). basically, all legume crops need more p for growth and seed development (sanginga et al., 2000). phosphorus plays important role to cowpea yields as it stimulates growth, initiates nodule formation as well as accelerates the efficiency of the rhizobium-legume symbiosis (haruna and aliyu, 2011). phosphorus stimulates root development and growth of young plants, giving them a good and vigorous start and control key enzyme reactions in the regulation of metabolic pathways. p favors increased leaf area and leaf area index by greater 26 putul et al. growth of the leaf blade (abayomi et al., 2008). p inputs either from soil reserves or from added fertilizer based on successful production systems of legumes (brynes and bumb, 1998). acquisition of p fertilizer by crop depends on soil and plant properties. the research on genotypic variation of cowpea and the effect of p on the growth and development is little in bangladesh. therefore, this study was aimed to determine the effects of different levels of p with genotypic variation on the growth and quality of four selected cowpea genotypes. materials and methods a field experiment was conducted at the agronomy research field of bangabandhu sheikh mujibur rahman agricultural university, gazipur 1706 from december 2016 to april 2017. the experimental site is located in madhupur tract under agro ecological zone (aez) 28 at geographic coordinate between 24°09´ n latitude and 90°26´ e longitude with an elevation of 8.4 m from the sea level. the experiment consisted of two factors viz. four cowpea genotypes i.e. bari felon-1(g1), a-06008 (g2), vi046192 (g3) and vi034386 (g4) and four levels of phosphorus like p0(no phosphorus i.e. control), p30(30 kg p ha-1), p60(60 kg p ha-1) and p90(90 kg p ha-1). the experiment was laid out in a randomized complete block design (rcbd) with three replications. the unit plot size was 1.5 m1.5 m with a planting configuration of 30 cm10 cm. a fertilizer dose of 30 kg n, 30 kg k, 10 kg s, 2 kg zn and 1 kg b ha-1 (barc, 2012) was applied as basal during final land preparation in the form of urea, muriate of potash (mop), sulfur, zinc sulphate and boric acid, respectively. different levels of phosphorus were applied as treatment in soil in the form of triple super phosphate (tsp). all fertilizers were applied during final land preparation. seeds of similar size were sown after treating with bavistin @ 2 g kg-1 of seeds. a light irrigation was provided immediately after sowing to ensure uniform emergence. plant protection measures were taken and intercultural operations were done whenever necessary. days to 1st flower initiation and 50% flowering from each plot were recorded. soil plant analysis development (spad) value of leaf was recorded from 3 plants in each plot at 120 das using a spad meter (model: spa-502, minolta camera co. ltd. japan). for growth estimation, sampling was done at 40, 60, 80, 100 and 120 das. at maturity, 1 m2 area excluding border was selected to record the agronomic parameters and yield. ten sample pods and ten sample seeds were used to measure pod length, seed length and breadth. grain yield was recorded and adjusted at 12% moisture content. absolute growth rate (agr), crop growth rate (cgr), relative growth rate (rgr), net assimilation rate (nar) and leaf area index (lai) were calculated using the following formulae: 1 dayg 1 t 2 t 1 w 2 w agr     1 dayg ga 1 1 t 2 t 1 w 2 w cgr      1 day 1 gg 1 t 2 t 1 lnw 2 lnw 1 t 2 t 1 w 2 w 1 w 1 rgr        1 day 2 mg 1 t 2 t 1 w 2 w 1 l 2 l 1 lnl 2 lnl nar         growth and yield of cowpea as influenced by different 27 area ground leafof area surface lai  where, w1 = dry weight at time t1 (g), w2 = dry weight at time t2 (g), ga = ground area (m2), ln = natural logarithm, l1 = leaf area at time t1 (m2), l2 = leaf area at time t2 (m2). the recorded data for different plant parameters were subjected to statistical analysis. statistix 10 software program was used to perform analysis of variation. the treatment means were compared using the least significant difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion days to 1st and 50% flowering cowpea genotypes showed significant variation in number of days required to 1st flower initiation. the genotype g4 took maximum time (99 das) and the genotype g1 required the lowest time (96 das) for 1st flowering (table 2). phosphorus (p) fertilizer did not exert significant effect on days to 1st flowering. however, the highest number of days to 1st flowering (97 das) was obtained from p90 and the lowest (97 das) in p0 as presented in table 2. interaction between genotypes and p (table 2) did not exert significant impact on days to 1st flowering. days required to 50% flowering differed significantly in the genotypes tested. the maximum number of days required for 50% flowering (112 das) was observed in the genotype g4 and genotype g1 needed significantly the lowest number of days (108 das) as presented in table 2. p fertilizer did not exert significant effect on days to 50% flowering (table 2). the tested cowpea genotypes showed a marked variation in 1st and 50% flowering. the variation in 1st and 50% flowering is due to the inherent characters of the cowpea genotypes. genotypic variation of flowering was also observed in common bean (wondimu and tana, 2017). variation in 1st and 50% flowering due to application of different levels of phosphorus has also been reported in cowpea (ayodele and oso, 2014; nkaa et al., 2014). absolute growth rate absolute growth rate (agr) showed a significant variation in the different cowpea genotypes tested. agr in genotypes g1, g2 and g4 increased progressively up to 100 das and in g3reached a peak at 80 das after that those genotypes gradually decreased. agr decreased as the plant matured because of cessation of vegetative growth and senescence of leaves and agr was decreasing after 80 das in genotype g3 and 100 das in genotypes g1, g2 and g4. among the genotypes, g1 registered a maximum agr (0.71 g day-1) and genotype g3 gave the lowest agr (0.17 g day-1) at 100 das (fig. 1a). different p levels significantly influenced the growth of cowpea. agr increased gradually with time reaching a peak at 100 das and declined afterwards till 120 das regardless of the p levels. plants treated with p60 showed the highest agr (0.56 g day-1) and p0 gave the lowest agr (0.38 g day-1) at 100 das (figure 2a). these results are in accordance with the findings of seyed et al. (2011). the interaction of g3p90 gave the lowest (-0.15 g day-1) and g1p30 gave the highest agr (0.95 g day-1) at 100 das (table 1). crop growth rate crop growth rate (cgr) in different genotypes varied significantly as shown in fig. 1b. cgr in genotypes g1, g2 and g4 increased progressively up to 100 das and g3 reached a peak at 80 das after that those genotypes gradually decreased (fig. 1b). the highest cgr (23.69 g m-2 28 putul et al. day-1) was obtained in the genotype g1 and the lowest (5.64 g m-2 day-1) in genotype g3. different p levels significantly influenced the growth of cowpea. cgr increased gradually with time reaching a peak at 100 das and declined afterwards till 120 das regardless of the p levels. similar result was reported that values of crop growth rate are normally low during early growth stages and increase with time, reaching maximum values at about the time of flowering (fageria et al., 2006). application of p enhanced leaf growth, reduced leaf senescence and helped intercept more radiation resulting in greater amount of photosynthesis. among the levels of p, p60 registered a maximum cgr (18.56 g m-2 day-1) while p90 gave the lowest cgr (12.82 g m-2 day-1) at 100 das (fig. 2b). ehsan et al. (2017) also found the highest cgr applying 60 kg pha-1at all the growing period of mungbean. the interactions between genotypes and levels of p also showed significant variation in crop growth rate throughout the growing periods (table 1). at 100 das the interaction of g1p30 gave the highest (31.79 g m-2 day-1) and g3p60 gave significantly the lowest cgr (3.14 g m-2 day-1). relative growth rate the relative growth rate (rgr) gives the efficiency of current dry matter to produce future dry matter. rgr was high in early of the growth period and showed decreasing trend as the crop advanced in age (fig. 1c). rgr decreases as the plant ages due to the fact that an increasing part of the plant is structural rather than metabolically active tissue and as such does not contribute to growth (chattjrvedi et al., 1980). among the genotypes tested, the highest rgr was 0.08 g m-2 day-1 in genotype g4 and the lowest in genotype g2 (0.05 g g-1 day-1) at 60 das. the rgr was significantly influenced by different p levels. however, irrespective of different p levels, rgr was pronounced early in the season and showed a decreasing trend as the crop advanced towards maturity (fig. 2c). similar decreasing trend of rgr was also reported by ehsan et al. (2017) in mungbean. p90 registered maximum rgr (0.07 g g-1 day-1) while plants treated with p0 gave the lowest rgr (0.05 g g-1 day-1) at 60 das in this study. again, the interaction effect of genotypes and different levels of p on rgr was found significant. the interaction of g4p90 gave the highest rgr (0.09 g g-1 day-1) and g2p0 gave the lowest (0.01 g g-1 day-1) at 60 das (table 1). net assimilation rate net assimilation rate (nar) is a value that relates plant productivity to plant size. it is useful as a measure of the photosynthetic efficiency of plants and reflects the balance of photosynthetic rate against respiration and tissue loss rates (quero et al., 2006). in the present study, different genotypes showed significant effect on nar under different p levels (fig.1d). nar increased progressively from 60 das to 100 das after that the trend decreased in all the studied genotypes except g3. nar in the genotype g3 increased gradually from 60 das to 80 das after that it decreased (fig. 1d). at 100 das, the genotype g1 gave the highest nar (4.10g m-2 day-1) and g3 genotype gave the lowest (1.40 g m-2 day-1). different levels of p showed significant effect on nar. nar increased progressively up to 100 das in all levels of p after that the trend decreased gradually (fig. 2d). at 100 das, p60 gave the highest nar (3.54 g m-2 day-1) and p90 gave the lowest (2.15 g m-2 day-1). likely, the interaction between genotypes and different p levels showed significant impact on nar. the interaction of g4p60 gave the highest (5.96 g m-2 day-1) and g3p60 gave the lowest (0.75 g m-2 day-1) nar at 100 das (table 1). nar decreased during the growing season as more and more leaves were fully or partially shaded. also, the decrease in nar with plant age may be due to older average leaf age which resulted in lower photosynthetic efficiency. growth and yield of cowpea as influenced by different 29 leaf area index leaf area index (lai) depends on number of leaves and leaf expansion in a plant. leaf area is made up of the total green area of emerged leaves (keating and carbery, 1993). it was indicated that leaf area index, leaf area duration and dry matter accumulation during the reproductive period strongly influence the yield components (liu et al., 2004). greater leaf area is necessary to have superior yield components in grain legumes (muchow, 1985). here, lai increased progressively up to 100 das in all cowpea genotypes after that it gradually decreased (fig. 1e). at 100 das, the highest lai (6.68) was obtained in the genotype g1 and the lowest (5.03) in genotype g3. the variation in lai among the genotypes might be due to genetic character of the genotypes. greenness duration the greenness of different genotypes at 120 das was measured by spad meter. the highest spad value (51.03) was obtained in the genotype g1 and the lowest (46.48) in g3 (fig. 1f). the general trend was an increase in spad value with the increase in p levels except in p60 though the variation wasn’t significant. at 120 das, the highest spad value (50.98) was recorded at p90 and the lowest (47.19) at p60 (fig. 2f). the interaction of genotypes and p levels did not exert significant impact on spad value of cowpea (table 1). 30 putul et al. fig. 1. variation in (a) absolute growth rate (agr), (b) crop growth rate (cgr), (c) relative growth rate (rgr), (d) net assimilation rate (nar), (e) leaf area index (lai) and (f) spad values of cowpea genotypes over time. vertical bars indicate lsd (0.05). (c) (b) (d) (e) (f) (a) growth and yield of cowpea as influenced by different 31 fig. 2. variation in (a) absolute growth rate (agr), (b) crop growth rate (cgr), (c) relative growth rate (rgr), (d) net assimilation rate (nar), (e) leaf area index (lai) and (f) spad values due to different levels of p over time in cowpea genotypes. vertical bars indicate lsd (0.05). (a) (d) (b) (c) (e) (f) 32 putul et al. table 1. interaction effect of cowpea genotypes and levels of p on absolute growth rate (agr), crop growth rate (cgr), relative growth rate (rgr), net assimilation rate (nar), leaf area index (lai) and spad value over time interaction (g×p) agr at different das cgr at different das rgr at different das nar at different das lai at different das spad value 60 80 100 120 60 80 100 120 60 80 100 120 60 80 100 120 40 60 80 100 120 120 g1p0 0.09 0.34 0.74 -0.25 3.06 11.17 24.76 -8.42 0.07 0.07 0.05 -0.01 2.36 3.05 4.63 -1.63 0.48 2.76 4.73 6.02 4.38 49.93 g1p30 0.12 0.32 0.95 -0.12 3.84 10.54 31.79 -4.13 0.07 0.06 0.06 0.00 2.48 2.76 5.63 -0.71 0.75 2.78 5.10 6.24 5.37 52.47 g1p60 0.11 0.24 0.59 0.38 3.56 7.95 19.51 12.59 0.06 0.05 0.05 0.02 2.10 1.93 3.37 2.10 0.74 3.26 5.14 6.48 5.55 52.73 g1p90 0.09 0.36 0.56 0.31 2.86 12.01 18.69 10.41 0.05 0.07 0.04 0.01 1.46 2.43 2.74 1.54 0.72 4.17 5.80 7.97 5.69 56.21 g2p0 0.03 0.25 0.28 0.19 0.95 8.45 9.35 6.25 0.01 0.05 0.03 0.01 0.77 2.63 1.99 1.10 0.47 2.57 3.97 5.51 5.84 45.10 g2p30 0.13 0.19 0.54 -0.08 4.32 6.28 18.01 -2.75 0.07 0.04 0.05 0.00 3.08 1.63 3.35 -0.55 0.48 3.09 4.71 6.09 4.03 49.87 g2p60 0.08 0.22 0.66 -0.27 2.74 7.41 21.95 -9.01 0.06 0.05 0.05 -0.02 2.53 2.61 4.09 -1.72 0.62 1.74 4.34 6.56 4.08 50.23 g2p90 0.10 0.42 0.44 0.04 3.35 13.95 14.80 1.41 0.06 0.07 0.03 0.00 2.16 3.45 2.32 0.23 0.73 2.83 5.57 7.24 5.07 51.70 g3p0 0.06 0.14 0.16 0.19 1.95 4.75 5.32 6.39 0.06 0.05 0.03 0.02 2.94 2.34 1.40 1.83 0.31 1.22 3.15 4.54 2.64 48.87 g3p30 0.05 0.24 0.27 0.07 1.50 8.01 9.04 2.35 0.04 0.07 0.03 0.01 2.97 5.26 2.27 0.49 0.39 0.64 2.98 5.21 4.46 48.20 g3p60 0.05 0.21 0.09 0.25 1.80 7.11 3.14 8.41 0.06 0.07 0.01 0.03 2.62 3.58 0.75 1.79 0.46 0.98 3.53 4.96 4.45 39.57 g3p90 0.07 0.09 0.15 0.16 2.36 3.10 5.05 5.26 0.08 0.04 0.03 0.02 2.26 1.29 1.20 1.21 0.57 1.74 3.21 5.40 3.45 49.30 g4p0 0.09 0.21 0.73 -0.31 3.16 6.87 24.18 -10.30 0.08 0.05 0.06 -0.02 3.11 2.05 4.62 -2.09 0.40 2.07 5.07 5.41 4.50 49.300 g4p30 0.10 0.30 0.25 0.21 3.46 9.94 8.22 7.09 0.08 0.06 0.02 0.01 2.42 2.97 1.86 1.61 0.58 2.87 3.88 5.02 3.84 44.00 g4p60 0.07 0.36 0.89 -0.18 2.40 11.93 29.63 -5.89 0.06 0.07 0.05 -0.01 1.92 3.62 5.96 -1.18 0.66 2.13 4.83 5.12 4.91 46.23 g4p90 0.12 0.16 0.38 0.34 3.86 5.34 12.75 11.44 0.09 0.04 0.04 0.02 2.33 1.34 2.33 2.01 0.72 3.18 4.93 6.05 5.33 53.93 lsd (0.05) 0.00 0.00 0.00 0.00 0.10 0.14 0.13 0.10 0.00 0.00 0.00 0.00 0.13 0.10 0.07 0.05 0.02 0.09 0.13 0.11 0.13 ns cv (%) 2.09 0.99 0.47 3.05 2.09 0.99 0.47 3.05 4.02 1.31 0.83 2.40 3.44 2.24 1.43 7.42 1.56 2.36 1.71 1.08 1.65 11.37 das = days after sowing growth and yield of cowpea as influenced by different 33 different levels of p significantly influenced the lai (fig. 2e). regardless of the levels of p, lai increased progressively up to 100 das in all p treatments after that it gradually decreased (fig. 2e). plants treated with p90 showed the highest lai (6.67) and p0 showed the lowest (5.37) at 100 das. variation in lai due to the application of different levels of p in cowpea was also reported in several studies (ayodele and oso, 2014; nkaa et al., 2014). the interaction effect of genotypes and levels of p was also significant on lai throughout the growth period (table 1). at 100 das the best interaction was g1p90 which gave the highest (7.97) and g3p0gave the lowest (4.54) lai. increase in lai due to increasing rate of applied p might be attributed to welldeveloped root system of the genotypes favored by p uptake. these findings were also supported by the results found in soybean (singh and bansal, 2000). pod length pod length was significantly influenced by the variation in genotypes and different levels of p. the longest pod (18.31 cm) was recorded in genotype g4 and the shortest (8.59 cm) in g3 (table 2). application of different levels of p showed significant influence on pod length. the p90 had the longest pod (14.33 cm) and p30 had the shortest (13.94 cm) as presented in table 10. nkaa et al. (2014) also showed an increasing pod length due to p application in cowpea. the interaction of genotypes and different levels of p showed significant impact on pod length. the highest pod length (19.1 cm) was measured from the g4p30 interaction and the shortest (7.78 cm) from g3p30 (table 2). seed length and breadth seed length and breadth in cowpea genotypes varied significantly as shown in table 2. the average highest seed length and breadth (0.71 cm and 0.54 cm, respectively) were obtained in the genotype g1 and the lowest in g3 (0.62 cm and 0.43 cm, respectively). application of different levels of p also showed significant influence on seed length and breadth. the average lowest seed length and breadth (0.67 cm and 0.47 cm, respectively) were obtained in p0 and the highest (0.70 cm and 0.50 cm, respectively) in p60 and p90 (table 2). the interaction between genotypes and levels of p showed significant effect on seed length and breadth (table 2). the g1p60 interaction gave the highest seed length and breadth (0.77 cm and 0.60 cm, respectively) and g3p0, g3p30 and g3p60 had the lowest (0.60 cm and 0.40 cm, respectively). grain yield both genotypes and p levels exerted significant influence on grain yield. genotypic variations in grain yields were evident (table 2). the genotype g2 gave significantly the highest grain yield (0.62 t ha-1) and g4 gave the lowest (0.03 t ha-1). grain yield also increased significantly with increasing level of p. p0 obtained the lowest (0.27 t ha-1) and p90 obtained the highest (0.34 t ha-1) grain yield (table 2). moreover, the interaction of genotypes and different p levels exerted significant effect on grain yield (table 2). g2p90 gave the highest grain yield (0.69 t ha-1) and g4p30 gave the lowest (0.01 t ha-1). the tested cowpea genotypes varied significantly in their grain yield though different p levels exerted significant influence on it. grain yield increased with the increasing level of p. this might be due to the fact that p90 contributed to the highest nar, lai, greenness duration, pod length, seed length and breadth. these results are in accordance with the findings obtained by nkaa et al. (2014) and singh et al. (2011). 34 putul et al. table 2. days to 1st flowering, days to 50% flowering, pod length, seed length, seed breadth and grain yield of cowpea genotypes as influenced by different levels of p genotypes (g) days to 1st flowering (das) days to 50% flowering (das) pod length (cm) seed length (cm) seed breadth (cm) grain yield (t ha-1) g1 95.67 107.75 14.83 0.71 0.54 0.51 g2 96.67 108.50 14.70 0.70 0.50 0.62 g3 97.67 109.08 8.59 0.62 0.43 0.04 g4 99.25 112.08 18.31 0.70 0.50 0.03 lsd (0.05) 0.44 0.73 1.00 0.02 0.02 0.01 cv (%) 0.55 0.80 8.89 3.87 5.87 3.32 phosphorus (p kg ha-1) days to 1st flowering (das) days to 50% flowering (das) pod length (cm) seed length (cm) seed breadth (cm) grain yield (t ha-1) p0 97.17 109.08 14.02 0.67 0.47 0.27 p30 97.22 109.50 14.13 0.68 0.50 0.28 p60 97.25 109.33 13.9 0.70 0.50 0.32 p90 97.42 109.50 14.33 0.70 0.50 0.34 lsd (0.05) ns ns 1.04 0.02 0.02 0.01 cv (%) 0.55 0.80 11.84 3.87 5.87 3.32 interaction (g×p) days to 1st flowering (das) days to 50% flowering (das) pod length (cm) seed length (cm) seed breadth (cm) grain yield (t ha-1) g1p0 95.67 107.67 14.80 0.67 0.47 0.39 g1p30 95.67 108.00 15.62 0.72 0.60 0.59 g1p60 95.67 107.67 14.19 0.77 0.60 0.49 g1p90 95.67 107.67 14.72 0.70 0.50 0.56 g2p0 96.67 108.00 14.55 0.70 0.50 0.65 g2p30 97.00 109.00 14.04 0.70 0.50 0.49 g2p60 96.33 108.33 14.89 0.70 0.50 0.67 g2p90 96.67 108.67 15.31 0.70 0.50 0.69 g3p0 97.33 109.00 8.68 0.60 0.40 0.03 g3p30 97.67 108.67 7.78 0.60 0.40 0.02 g3p60 97.67 109.00 8.42 0.60 0.40 0.09 g3p90 98.00 109.67 9.46 0.67 0.50 0.04 g4p0 99.00 111.67 18.1 0.70 0.50 0.02 g4p30 99.33 112.33 19.1 0.70 0.50 0.01 g4p60 99.33 112.33 18.25 0.70 0.50 0.03 g4p90 99.33 112.00 17.83 0.70 0.50 0.08 lsd (0.05) ns ns 2.09 0.04 0.05 0.02 cv (%) 0.55 0.80 11.84 3.87 5.87 3.32 conclusions growth and quality parameters of four cowpea genotypes in response to four phosphorus fertilizer application levels were evaluated. growth and quality of cowpea were influenced by different phosphorus levels though genotypic variation was conspicuous. the results revealed that among the four selected cowpea genotypes, the highest absolute growth rate, crop growth rate, relative growth rate, leaf area index, greenness duration and seed length and breadth were obtained from bari felon-1, but the genotype a-06008 gave the highest grain yield (0.62t ha-1). plants with phosphorus 90 kg ha-1 gave the highest leaf area index, greenness duration, growth and yield of cowpea as influenced by different 35 pod length, seed length, breadth and grain yield (0.34 t ha-1). the genotype a-06008 gave the highest grain yield (0.69 t ha-1) at p 90 kg ha-1. references abayomi, y.a., t.v. ajibade, o.f. sammuel and b.f. sa´adudeen. 2008. growth and yield responses of cowpea (vignaunguiculata (l.) walp) genotypes to nitrogen fertilizer (n) application in the southern guinea savanna zone of nigeria. asian j. plant sci. 7(2): 170176. ayodele, o.j. and a.a. oso. 2014. cowpea responses to phosphorus fertilizer application at adoekiti, south-west nigeria. j. appl. sci. agric. 9(2): 485-489. barc (bangladesh agricultural research council). 2012. fertilizer recommendation guide, bangladesh agricultural research council, farmgate, dhaka 1215, p.274. biswas, p.k., j.u. ahmed, r.r. saha and g.s. torofder. 1996. response of different nitrogen levels on nodulation, dry matter and seed yield in cowpea genotypes. bangladesh j. agric. res. 21(1): 75-79. brynes, b.h. and b.l. bumb. 1998. population growth, food production and nutrient requirements in nutrient use in crop production. ed. z. rengel. food product press, new york, london. chattjrvedi, g.s., p.k. aggarwal and s.k. sinha. 1980. growth and yield of determinate and indeterminate cowpeas in dry land agriculture. j. agric. sci., camb. 94: 137-144. dugje, i.y., l.o. omoigai, f. ekeleme, a.y. karama and h. ajeigbe. 2009. farmer’s guide to cowpea production in west africa. iita, ibadan, nigeria, p.20. ehsan, q., d.s. rana, and a.k. choudhary. 2017. effect of crop establishment methods and phosphorus nutrition on growth and productivity of mungbean (vigna radiata l. wilczek) in semi-arid afghanistan. ann. agric. sci. 38(2): 200-207. fageria, n.k., v.c. ballgar and r. clark. 2006. physiology of crop production. haworth press inc. pp.23-56. fao (food and agriculture organization). 2005. cowpea production database for nigeria 19902004. http://www.faostat.fao.org/. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research, second edition, john wiley and sons inc., new york. haruna, i.m. and l. aliyu. 2011. yield and economic returns of sesame (sesamum indicum l.) as influenced by poultry manure, nitrogen and phosphorus at samaru, nigeria. elixir agric. 39: 4884-4887. keating, b.a. and p.s. carbery. 1993. resources capture and use in intercropping solar radiation. field crops res. 34: 273-301. langyintuo, a.s., j. lowenberg-deboer, m. faye, d. lamber and g. ibro. 2003. cowpea supply and demand in west africa. field crops res. 82: 215-231. liu, x., j. jin, s.h. herbert, q. zhang and g. wang. 2004. yield components, dry matter, leaf area index and leaf area duration of soybean in northeast china. chinese academy of sciences. field crops res. 93(1): 85-89. mfeka, n., r.a. mulidzi and f.b. lewu. 2019. growth and yield parameters of three cowpea (vigna unguiculata l. walp) lines as affected by planting date and zinc application rate. s. afr. j. sci. 115(12): 1-9. muchow, r.c. 1985. analysis of the effects of water deficits on grain legumes grown in a semi-arid tropical environment in terms of radiation, interception and its efficiency of use. field crops res. 11(4): 309-323. http://www.faostat.fao.org/ 36 putul et al. nkaa, f.a., o.w. nwokeocha and o. ihuoma. 2014. effect of phosphorus fertilizer on growth and yield of cowpea (vignaunguiculata). j. pharm. biol. sci. 9(5):74-82. quero, j.l., r. villar, t. marañón, r. zamora, d.b. vegaand l.d. sack. 2006. relating leaf photosynthetic rate to whole-plant growth: drought and shade effects on seedlings of four quercus species. funct. plant biol. 35:725-737. sanginga, n., o. lyasse and b.b. singh. 2000. phosphorus use efficiency and nitrogen balance of cowpea breeding lines in a low p soil of the derived savanna zone in west africa. plant soil. 220: 119-128. seyed, a.v. and a.f. hossein. 2011. mycorrhizal fungi influence on physiological growth indices in basil induced by phosphorus fertilizer under irrigation deficit conditions. world acad. sci. eng. technol. 59: 2182-2184. singh, a., a.l. baoule, h.g. ahmed, a.u. dikko, u. aliyul, m.b. sokoto, j. alhassan, m. musa and b. haliru. 2011. influence of phosphorus on the performance of cowpea (vigna unguiculata l. walp.) varieties in the sudan savanna of nigeria. agric. sci. 2(3): 313-317. singh, s.p. and k.n. bansal. 2000. response of soybean (glycinemax) to nitrogen, its application time and sulphur. indian j. agric. sci. 70(1): 34-36. william, e. 2016. introduction of short duration pulses into rice-based cropping systems in western bangladesh. australian center for international agricultural research. australian government. wondimu, w. and t. tana. 2017. yield response of common bean (phaseolus vulgaris l.) varieties to combined application of nitrogen and phosphorus fertilizers at mechara, eastern ethiopia. j. plant biol. soil health. 4(2): 7. bangladesh agron. j. 2019, 22 (1): 7-13 development of vegetable based cropping pattern in cumilla region s.k. bhowal1*, m.h. hossain2, m.m. bashir3 and a.s.m.m.r. khan4 1scientific officer, 2 principal scientific officer, 3senior scientific officer, ofrd, bari, cumilla, bangladesh 4chief scientific officer, ofrd, bari, gazipur, bangladesh *correspondng e-mail: shamal.bau@gmail.com (received: 12 february 2019, accepted: 03 october 2019) keywords: vegetable, cropping pattern, intensive cropping, productivity and profitability abstracts a field experiment was conducted at mlt site, chandina under on-farm research division (ofrd), bangladesh agricultural research institute, cumilla during 2015-16 and 2016-17 to study an economically profitable vegetable based cropping pattern in cumilla region for increasing cropping intensity and productivity as well as to meet the vegetable demand for farm family as well as the country. the studied vegetable based cropping patterns were cp1: red amaranth-potato-coriander-indian spinach-ladies finger-cauliflower and cp2: red amaranth-potato-indian spinach-ladies finger-coriander-red amaranth, respectively. the results showed that six vegetable crops could be grown successfully one after another in a sequence in the farmer’s field instead of two or three crops based pattern in a piece of land. from the research results it was revealed that the highest potato equivalent yield (pey) 226.66 t ha-1 was obtained from cropping pattern cp1: red amaranth-potato-coriander-indian spinach-ladies finger-cauliflower where the lower pey (171.38 t ha-1) in cp2: red amaranth-potato-indian spinach-ladies finger-coriander-red amaranth cropping pattern. from the economic analysis, it was observed that the highest gross return tk. 22,66,600 ha-1 was obtained from cropping pattern cp1: red amaranth-potato-coriander-indian spinachladies finger-cauliflower which leads to the highest gross margin (tk. 18,94,542 ha-1) as well as the highest bcr (6.09) from that cropping pattern compared to cp2. introduction crop diversification is the growing of different species of crops in a farm or area or region or nation either in succession or simultaneously or both together in the course of the year. while crop intensification is the growing of crop with intensive care and management by utilizing modern technique and technology to maximize production in a unit of land with the accommodation of more number of crops per year. horticulture, is the largest single sub-sector of the economy, accounting for about 13 percent of the country’s (government of bangladesh, 2006). several studies have pointed out that there is considerable potential for growing horticultural crops in bangladesh (fao, 1997; bouis, 2000). farmers who are engaged in the production of vegetables often earn higher incomes than those engaged in the production of cereal crops alone (weinberger and lumpkin, 2005). vegetables like eggplant, radish, cabbage, cauliflower, and pumpkin gave returns at least three times higher than rice (ateng, 1998). in addition, the economic returns in terms of domestic resource cost at export parity also indicate that there is a comparative advantage in the production of vegetables in bangladesh (shahabuddin and dorosh, 2002). therefore, the natural and comparative advantages of bangladesh create promising opportunities for the 12 bhowal et al. b sector (adb, 2004). vegetables are a very popular crop and grown all over bangladesh which supply enormous nutrient for us. farmers of the cumilla, specially sayadpur, nimsar, korpai and chandina areas grow 3-5 vegetables whole the year haphazardly. most of the farmers grow hybrid vegetable varieties in their field due to the high yielding potentiality and seeds availability in the local market. the coverage of vegetable-vegetable-t. aman cropping pattern in cumilla district is 6300 ha (dae, 2017). so, the present study was carried out to establish and selection of suitable vegetable based cropping pattern in cumilla region of bangladesh. materials and methods the vegetable based intensive cropping pattern study was conducted during 201516 and 2016-17 at the farmers' field of nimsar and sayadpur at mlt site of chandina, cumilla under aez 19 to study an economically profitable vegetable based cropping pattern in cumilla region for increasing cropping intensity and productivity as well as to meet the vegetable demand for farm family whole the year round. the experiment was laid out in a randomized complete block design with three dispersed replications. there were two vegetable based cropping patterns i.e., cp1: red amaranth-potato-coriander-indian spinach-ladies fingercauliflower and cp2: red amaranth-potato-indian spinach-ladies finger-corianderred amaranth. the unit plot size was 02 decimal. red amaranth was the first crop of both the crop sequences. average weather data (2015-17) of cumilla district was presented in figure 1. the soil sample collection and analysis before and after the cropping pattern are presented in the table 1. fertilizer management and other intercultural operations were done according to azad et al. (2017) and fertilizer recommendation guide (2012). the details of the crop management for the cropping patterns have been presented in the table 2. plant protection measures were taken when required. intercultural operations were done as and when necessary. data on yield of the all crops were recorded carefully. the gross economic return was calculated on the basis of prevailing market price of the commodities. potato equivalent yield (pey) = [vegetable yield (kg) x vegetable price (tk. kg-1)] / price of potato (tk. kg-1) was also calculated. table 1. initial and final soil properties of the farmer’s field at mlt site chandina, cumilla during 2015-16 and 2016-17 soil properties land type ph organic matter (%) k total n (%) p zn b meq100 ml-1 µgml-1 initial mhl 5.4 1.85 0.14 0.14 10.5 1.78 0.20 final mhl 5.3 1.89 0.16 0.15 10.9 1.76 0.21 critical level 0.12 0.12 8. 0 0.6 0.20 source: srdi, regional laboratory, cumilla vegetable based croping pattern 13 table 2. crop management practices in the experimental plot under different cropping patterns at cumilla during 2015-16 & 2016-17 parameters cropping pattern (cp1) crop red amaranth potato coriander indian spinach ladies finger cauliflower variety bari lalshak1 bari alu46 bari dhonia2 bari puishak-1 bari dherosh2 meradona planting date 22-24, oct. 25-27, nov. 20-22, feb. 02-05, april 29-30, may 15-18, august spacing (cm) broadcasting 60 cm x 20 cm broadcasting broadcasting 50 cm x 40 cm 60 cm x 40 cm fertilizer dose (n-pk-s-zn-b kg ha-1) 25-7-12-3-10.5 47-12-80-71.5-1 27-15-18-60.8-0.5 37-15-22-5-0.50.5 42-19-22-7-0.80.5 48-25-38-101-0.5 field duration 18-20 77-80 32-34 45-50 45-65 61-65 turn around time 1 12-13 3 5-7 1 7 harvesting date 12-15 nov. 15-17 feb. 25-27 march 20-28 may 15 july-10 august 18-22 oct. parameters cropping pattern (cp2) crop red amaranth potato indian spinach ladies finger coriander red amaranth variety bari lalshak1 bari alu46 bari puishak1 bari dherosh-2 bari dhonia-2 bari lalshak-1 planting date 22-24 oct. 25-27 nov. 20-21 feb. 8-10 april 18-20 july 5-7 sep. spacing (cm) broadcasting 60 cm x20 cm broadcasting 50 cm x40 cm broadcasting broadcasting fertilizer dose (n-pk-s-zn-b kg ha-1) 25-7-12-3-10.5 47-12-80-71.5-1 37-15-22-50.5-0.5 42-19-22-7-0.80.5 27-15-18-6-0.80.5 25-7-12-3-10.5 field duration (days) 19 77-80 40-46 56-86 30-40 20-22 turn around time 23 12-13 2-3 1 1 5 harvesting date 10-12 nov. 15-17 feb. 3-8 april. 05 june-18 july. 20-30 august 27-29 sep. planting/transplanting and harvesting dates are the ranges of 2 years (2015-16 & 2016-17) 12 bhowal et al. b fig. 1. average monthly weather data of cumilla region (october, 2015 to april, 2017) source: meteorological department, regional station, brri, cumilla results and discussion yield of vegetables average yield and economic performance of vegetable based cropping pattern during 2015-16 and 2016-17 are presented in table 3 and 4. from the result, it was observed that the average vegetable yield of red amaranth-potatocoriander-indian spinach-ladies finger-cauliflower cropping pattern were recorded as 10.74, 35.7, 4.4, 30.99, 16.55 and 20.13 t ha-1, respectively where another pattern (red amaranth-potato-indian spinach-ladies finger-coriander-red amaranth) produced yield of 10.37, 39.52, 33.95, 15.85, 4.2 and 10.42 t ha-1, respectively. potato equivalent yield total productivity of different cropping sequences was determined by rice equivalent yield (rey) due to rice based cropping pattern but in this study cropping patterns are vegetable based cropping patterns which were calculated from the yield of component crops. total productivity of studied cropping patterns was calculated by potato equivalent yield (pey) which was different under different cropping sequences. from the two years result of vegetable based cropping pattern, it was found that the average highest pey (226.66 t ha-1) was recorded from the cropping sequence of red amaranth-potato-coriander-indian spinach-ladies finger-cauliflower and lowest (171.38 t ha-1) was found from the cropping sequence of red amaranth-potato-indian spinach-ladies finger-corianderred amaranth. potato equivalent yield (pey) in cp1 was almost 32 % higher than the cropping pattern cp2 due to the inclusion of high value summer vegetable (cauliflower). research findings of mandal et al. (2014) and mandal et al. (2015) closely related to the present study & also stated that inclusion of one oil crop or tuber crop in three or four crops based cropping pattern sharply increase the potato equivalent yield or rice equivalent yield of cropping pattern. soil fertility amendment 181.61 203.22 0 0 0.2 165.1 345 245.11 335.28 554.99 509.88 263.41 241.33 8.89 177.8 0 0 1.27 240.03 0 100 200 300 400 500 600 o ct b er n o v em b er d ec em b er ja n u ar y f eb ru ar y m ar ch a p ri l m ay ju n e ju ly a u g u st s ep te m b er o ct b er n o v em b er d ec em b er ja n u ar y f eb ru ar y m ar ch a p ri l 2015 2016 2017 tem. (max) temp. (min) vegetable based croping pattern 13 in both the vegetable based cropping patterns soil organic matter, available p, b and exchangeable k increased after two year cycles (table 1). total n also increased to some extent. after completion of six vegetables in two cropping pattern, it was observed that all the parameters increased with some exceptions. due to intensive cropping, substantial amount of well decomposed cowdung was applied before every vegetable in both the patterns. residues of some crops or vegetables such as potato, cauliflower, indian spinach etc. were also incorporated in the soil. for these reasons there were no depletion of soil nutrients in the subsequent years but more or less some soil organic matter and nutrients increased (table 1). therefore, soil fertility can be maintained by proper fertilizer management in intensive crop cultivation. furthermore, adequate intercultural operations, soil amendment and soil treatment along with proper fertilizer management produced higher crop yield. from the above results, it can be suggested that intensive vegetables based cropping patterns, which include potato, are suitable for rich farmers. growing of six vegetables in a year in a land and inclusion of summer cauliflower into the fallow period in a cropping pattern (cp1) could increase the cropping intensity and productivity. hossain et al. (2014) and hossain et al. (2017) also reported the soil fertility management in four crops based cropping pattern or intensive cropping that supports the vegetable based cropping pattern. economic analysis economic analysis was done on the basis of prevailing market price of the commodities. economics of system productivity of vegetable based cropping sequences showed in figure 2. it was revealed that the gross return varies from one cropping pattern to another cropping pattern due to inclusion of high value vegetable crop. higher gross return (tk. 2266600.00 ha-1) and gross margin (tk. 1894542.00 ha-1) were obtained in red amaranth-potato-coriander-indian spinachladies finger-cauliflower cropping pattern and comparatively lower gross return (tk. 1713800.00 ha-1) and gross margin (tk. 1387043.00 ha-1) was found in red amaranth-potato-indian spinach-ladies finger-coriander-red amaranth cropping pattern. higher total cultivation cost (tk. 372057 ha-1) was recorded from cropping sequence cp1 due to the inclusion of summer cauliflower where the lower (tk. 326757 ha-1) was obtained from the cropping sequence cp2. the higher mbcr (6.09) was calculated in improved cp1 (red amaranth-potatocoriander-indian spinach-ladies finger-cauliflower)cropping pattern compared to cropping pattern cp2: red amaranth-potato-indian spinach-ladies finger-corianderred amaranth (5.24). hossain et al., also reported that four crop based cropping pattern potato-boro-t. aus-t.aman is agronomically feasible and economically profitable compared to existing farmers cropping pattern potatoboro-fallow-t. aman. 12 bhowal et al. b table 3. average yield of red amaranth-potato-coriander-indian spinach-ladies finger-cauliflower and red amaranth-potato-indian spinach-ladies fingercoriander-red amaranth cropping patterns and pey at mlt site chandina under cumilla district during 2015-16 & 2016-17 cropping patterns yield (t ha-1) potato equivalent yield (pey) cp1 red amaranth potato coriander indian spinach ladies finger cauliflower 226.66 10.74 35.7 4.4 30.99 16.55 20.13 cp2 red amaranth potato indian spinach ladies finger coriander red amaranth 171.38 10.37 39.52 33.95 15.85 4.2 10.42 cp1: red amaranth-potato-coriander-indian spinach-ladies finger-cauliflower, cp2: red amaranthpotato-indian spinach-ladies finger-coriander-red amaranth, unit price/kg: red amaranth tk. 16, potato tk. 10, coriander tk. 20, indian spinach tk. 14, ladies finger tk.22, summer cauliflower tk. 50 fig. 2. economic performances of vegetable based cropping patterns at mlt site chandina under cumilla district (2015-16 & 2016-17). farmers’ opinion farmers opined that six vegetable crops could be grown successfully in the same field in a year but sometimes they are not more benefited from vegetables due to increased labor cost at pick period and lower market price in a wholesale market. conclusion from the two years study on the vegetable based cropping pattern, it could be concluded that six vegetable crops based cropping pattern such as red amaranthpotato-coriander-indian spinach-ladies finger-cauliflower and red amaranth-potatoindian spinach-ladies finger-coriander-red amaranth are agronomically feasible and economically profitable cropping pattern in cumilla region. due to intensive growing of six vegetable crops in a year in the same piece of land cropping 0 500000 1000000 1500000 2000000 2500000 gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) mbcr 2266600 372057 1894542 6.09 1713800 326757 1387043 5.24 cp1 cp2 vegetable based croping pattern 13 intensity and productivity were sharply increased. more employment opportunity for male and female labors is generated at the same time due to the increased production of seasonal and off season vegetables. the food and nutritional security is ensured for the farmers and the nation as a whole. references asian development bank (adb). 2004. draft final report on agribusiness development project in bangladesh. dhaka: bangladesh ministry of agriculture. ateng, b. 1998. comparative advantage and crop diversification in bangladesh. bangladesh: agriculture in the 21st century. dhaka: the university press. azad, a.k., b.k. gossami, m.l. rahaman, p.k. malakar, m.s. hasan (edited). 2017. krishi projukti hatboi (handbook on agro-technology), bangladesh agricultural research institute. 7th edition, gazipur-1701, bangladesh. bouis, h.e. 2000. commercial vegetable and polyculture fish production in bangladesh: their impacts on household income and dietary quality. food and nutrition bulletin, 21(4): 482-487. mondal, r.i., f. begum and a. aziz. 2014. four crop based cropping pattern in one piece of land in a year (t. aman -mustard-boro-t. aus rice). (bengali booklet) bangladesh agricultural research institute, gazipur-170, bangladesh. p.31. mondal, r.i., f. begum, a. aziz and s.h. sharif. 2015. crop sequences for increasing cropping intensity and productivity. saarc j. agri. 13(1):135-147. dae (department of agricultural extension). 2017. annual extension report. presented in the regional research-extension review and program planning workshop. khamarbari, cumilla, bangladesh. fao (food and agriculture organization). 1997. horticulture baseline production and marketing survey, bangladesh. main report. vol. 2. rome: fao. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council (barc), farmgate, dhaka 1215. 274p. government of bangladesh (gob). 2006. bangladesh economic review. ministry of finance. government of the people’s republic of bangladesh. hossain, m.h., m.m. bashir, s.k. bhowal, q. naher, t. zahan, m.k. hasan and a.s.m.m.r. khan. 2017. production technology of four crop based cropping pattern mustard-boro-t. aus-t.aman rice in cumilla region (bengali booklet). ofrd (on-farm research division), bari, bangladesh. p.23. hossain, m.h., s.k. bhowal, m.m. bashir and a.s.m.m.r. khan. 2018. productivity and profitability of four crops based cropping pattern in cumilla region of bangladesh, the agriculturists.16(2): 88-92. hossain, i., r.i. mondal, m.j. islam, a. aziz, a.s.m.m.r. khan and f. begum. 2014. four crop based cropping pattern studies for increasing cropping intensity and productivity in rajshahi region of bangladesh. bangladesh agron. j. 17(2): 55-60. shahabuddin, q. and p. dorosh. 2002. comparative advantage in bangladesh crop production. discussion paper no. 47. international food policy research institute, usa. weinberger, k. and t.a. lumpkin. 2005. horticulture for poverty alleviation: the unfunded revolution. taiwan: the world vegetable center. microsoft word 6 bangladesh agron. j. 2017, 20 (2): 53-66 seedlingseedlingseedlingseedling growth of wheatgrowth of wheatgrowth of wheatgrowth of wheat as affected by soil salinityas affected by soil salinityas affected by soil salinityas affected by soil salinity e. sultanae. sultanae. sultanae. sultana1111, m. a. hasan, m. a. hasan, m. a. hasan, m. a. hasan2222,,,, s. sikders. sikders. sikders. sikder2222,,,, m. s. ranam. s. ranam. s. ranam. s. rana2222**** and f. alamand f. alamand f. alamand f. alam3333 1chandgong degree college, dinajpur 2department of crop physiology and ecology, hajee mohammad danesh sci. and tech. university, dinajpur 3office of the registrar, hajee mohammad danesh science and technology university, dinajpur *corresponding author, e-mail: sohel0901084@gmail.com (received:received:received:received: 29 may 2017, accepted:accepted:accepted:accepted: 23 august 2017) keywords:keywords:keywords:keywords: wheat genotypes, artificially developed soil salinity and seedling growth abstractabstractabstractabstract an experiment was conducted to evaluate seedling growth of wheat under saline condition. thirty wheat genotypes were grown in trays containing different levels of salinity (control, 6 and 12 dsm-1) during october to december, 2013. seedling emergence index, shoot and root length, shoot and root dry weight were found to be reduced with the increases of soil salinity level but the degree of reduction were not similar for all wheat genotypes. salt tolerance index (sti) also indicated a wide difference in salt tolerance among the wheat genotypes. sourav, gourav, shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 were more salt tolerance while baw 1177, baw 1190 and baw 1198 showed greater salt sensitivity than the other wheat genotypes at 6 ds m-1. however, at 12 ds m-1, sourav, gourav, shatabdi, sufi and baw 1184 showed more salt tolerance and baw 1183, baw 1190, baw 1192, baw 1194 and baw 97 provided greater stress sensitivity among the testing wheat genotypes. considering both saline stress sourav, gourav and shatabdi were found to be salt tolerant and baw 1190 was saline sensitive wheat genotypes. introductionintroductionintroductionintroduction salt stress affects seedling growth in different ways depending on plant species (gul and weber 1999). salinity affects the seedling growth of plants (tezara et al., 2003, rahman and kayani, 1988) by slow or less mobilization of reserve foods (kayani et al., 1990) suspending the cell division, enlargement (meiri and poljakoff – mayber, 1970) and injuring hypocotyls (assadian and miyamoto, 1987). generally, salinity can inhibit plant growth by three major ways (greenway and munns, 1980): a) water deficit arising from the more negative water potential (elevated osmotic pressure) of the soil solution; b) specific ion toxicity usually associated with either excessive chloride or sodium uptake; and c) nutrient ion imbalance when the excess of na+ or clleads to a diminished uptake of k+, ca2+, no3 or p, or to impaired internal distribution of one or another of these ions. therefore, boubaker (1996) showed that seedling characteristics are also viable criteria for selecting salt tolerance in wheat in a screening experiment of wheat cultivars. the relation of various seedling growth parameters to seed yield and yield component under saline conditions are important for the development of salt tolerant cultivar. the screening of salt tolerant lines/cultivars has been attempted by many researchers on various species at seedling growth stage (ashraf, 1999). therefore, the present study was conducted to evaluate the response of wheat genotypes to artificially developed saline soil at seedling stage. 54 sultana et al. materials materials materials materials the experiment was conducted on tr physiology and ecology, hajee mohammad danesh science and technology university (hstu), dinajpur during october 2013 to december 2013. collected from research field of hstu exchange capacity (cec) and ph value of the soil were 5.60 meq/100g and 5.45 respectively. the soil contained 1.19 % organic matter, 0.69 % organic carbon, 0.07 % total nitrogen, 16.75 ppm available phosphorou soil was analysed at srdi, dinajpur). each of 21 plastic bowl (diameter 18 cm) was filled with 10 kg of air dried soil. different amount (0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 % w/w) of nacl and na2so4 in a ratio of 1:1 was added in different plastic bowl thrice. before adding, the calculated amount of salt was dissolved in 1 litre plastic bowl were then kept under shade for air drying and pulverized every day. after complete air drying the soil in each bowl was mixed properly. the soil samples were collected from each plastic bowl for determining the soil salinity was plotted against the salt concentration and a standard curve was prepared which is shown in fig.1. artificial saline soil of different dsm calculated amount of nacl and na2so fig.1. relationship between soil salinity and salt concentration added in the soil. materials materials materials materials aaaand methodsnd methodsnd methodsnd methods the experiment was conducted on tray at the research field of the department of crop physiology and ecology, hajee mohammad danesh science and technology university (hstu), dinajpur during october 2013 to december 2013. the top soil (0-15 cm depth) was collected from research field of hstu, dinajpur. the soil was sandy loam and cation exchange capacity (cec) and ph value of the soil were 5.60 meq/100g and 5.45 respectively. the soil contained 1.19 % organic matter, 0.69 % organic carbon, 0.07 % total nitrogen, 16.75 ppm available phosphorous and 0.17 me/100g exchangeable potassium (the soil was analysed at srdi, dinajpur). each of 21 plastic bowl (diameter 18 cm) was filled with 10 kg of air dried soil. different amount (0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 % w/w) of nacl o of 1:1 was added in different plastic bowl. each treatment was replicated thrice. before adding, the calculated amount of salt was dissolved in 1 litre of tap water. the plastic bowl were then kept under shade for air drying and pulverized every day. after complete air drying the soil in each bowl was mixed properly. the soil samples were collected from each plastic bowl for determining the soil salinity level (rhoades et al., 1999). the soil salinity level was plotted against the salt concentration and a standard curve was prepared which is shown in artificial saline soil of different dsm -1 (0, 6 and 12 ds m -1) was developed by adding so4 in a ratio of 1:1 with the help of standard curve (fig.1). 1. relationship between soil salinity and salt concentration added in the soil. ay at the research field of the department of crop physiology and ecology, hajee mohammad danesh science and technology university 15 cm depth) was , dinajpur. the soil was sandy loam and cation exchange capacity (cec) and ph value of the soil were 5.60 meq/100g and 5.45 respectively. the soil contained 1.19 % organic matter, 0.69 % organic carbon, 0.07 % total s and 0.17 me/100g exchangeable potassium (the soil was analysed at srdi, dinajpur). each of 21 plastic bowl (diameter 18 cm) was filled with 10 kg of air dried soil. different amount (0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 % w/w) of nacl each treatment was replicated of tap water. the plastic bowl were then kept under shade for air drying and pulverized every day. after complete air drying the soil in each bowl was mixed properly. the soil samples were collected from each 1999). the soil salinity level was plotted against the salt concentration and a standard curve was prepared which is shown in ) was developed by adding in a ratio of 1:1 with the help of standard curve (fig.1). 55 influence of soil salinity on seedling growth of wheat eighteen try of 1.5m x 0.6m size was filled with artificially developed saline soil of different ds m -1 (0, 6 and 12 ds m -1). for the placement of seeds of thirty wheat genotypes in different artificially developed (0, 6 and 12 ds m -1) saline soil seeds were sown in the respective saline soil containing trays at the depth of 3cm. fifty seeds were sown in each line and there were 15 lines in each tray and every line contained single genotype. for thirty wheat genotypes two trays were required to complete a single treatment the experiment was replicated thrice having eighteen trays. growing of seedlings were allowed up to 30 days under an artificial shade or net house. intercultural operation like weeding was done to maintain normal growth of the crop. normal irrigation was given in each tray in every alternate day until harvesting. at 30 days after sowing, five seedlings from each treatment combinations were sampled. shoot and root length of individual seedling were recorded manually with scale. then the seedlings were dried separately at 70° c for 72 h in an electric oven (model03-54639, binder, germany) and weight were recorded with an electrical balance (modeland ek-300 i). salt tolerance index was calculated using following formula as goudarzi and pakniyat (2008) performance under salt stress condition sti = --------------------------------------------------------------- performance under normal stress condition the data were analyzed by partitioning the total variance with the help of computer using mstatc program. the treatment means were compared using tukey’s test. results and discussionresults and discussionresults and discussionresults and discussion emergence indexemergence indexemergence indexemergence index emergence index which indicates the speed of emergence was significantly influenced by interaction effect of salinity levels and wheat genotypes (table 1). emergence index was higher at control (with a range from 54.61 in gourav to 71.44 in baw-1182 and a mean of 63.70) moderate at moderate stress (with a range from 40.78 in baw 1199 to 62.11 in baw 1182 and a mean of 49.43) and lower at higher saline stress (with a range from 4.46 in baw 1199 to 29.16 in bari gom 25 and a mean of 19.03). the results showed that the speed of emergence was reduced with the increment of soil salinity stress but the degree of reduction in emergence index was not similar for all wheat genotypes at moderate and higher salinity stress compared to control. at moderate soil salinity stress, wheat genotypessourav,sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1184, baw 1185, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw 1194, baw 1196, baw 1197, baw 1198, baw 1199, baw 1200 and baw 1201 showed more than 20% reduction and wheat genotypesgourov, baw 1177, baw 1182, baw 1183, baw 1186, baw 1193 and baw 1195 showed less than 20% reduction in emergence index compared to control except in shatabdi in which emergence index was even increased. at higher soil salinity stress, only wheat genotypes shatabdi showed less than 50% reduction and all others genotypes showed more than 50% reduction in emergence index compared to control. 56 sultana et al. table 1. emergence index of different wheat genotypes as influenced by salinity levels wheat genotypes emergence index % change over control at 6 ds m-1 % change over control at 12 ds m-1 control saline (6 ds m-1) saline (12 ds m-1) sourav 63.87 50.79 10.75 -20.47 -83.17 gourav 54.61 50.79 18.50 -6.99 -66.12 shatabdi 56.65 59.58 28.84 +5.17 -49.09 sufi 66.60 49.69 28.91 -25.39 -56.59 bijoy 67.63 46.54 22.19 -31.18 -67.19 prodip 64.43 48.81 14.03 -24.24 -78.22 bari gom-25 66.43 51.23 29.16 -22.88 -56.10 bari gom-26 65.22 46.70 27.90 -28.39 -57.22 bari gom-27 63.87 50.41 23.14 -21.07 -63.77 bari gom-28 69.11 53.77 16.34 -22.19 -76.36 baw 1177 65.79 53.71 22.09 -18.36 -66.42 baw 1182 71.44 62.11 27.82 -13.05 -61.06 baw 1183 66.12 58.19 29.56 -11.99 -55.29 baw 1184 69.11 51.61 24.08 -25.32 -65.16 baw 1185 64.79 45.27 6.38 -30.12 -90.15 baw 1186 61.21 58.77 28.80 -3.98 -52.95 baw 1187 60.37 45.63 15.90 -24.41 -73.66 baw 1189 60.55 42.28 9.20 -30.17 -84.81 baw 1190 63.64 42.48 10.71 -33.25 -83.17 baw 1191 66.34 46.94 28.47 -29.24 -57.08 baw 1192 62.06 46.91 6.89 -24.41 -88.90 baw 1193 58.11 50.81 24.55 -12.56 -57.75 baw 1194 60.38 46.68 11.05 -22.69 -81.69 baw 1195 64.06 51.87 14.11 -19.03 -77.97 baw 1196 66.77 50.51 16.61 -24.35 -75.12 baw 1197 67.24 46.59 17.29 -30.71 -74.29 baw 1198 59.34 45.56 6.26 -23.22 -89.45 baw 1199 56.16 40.78 4.46 -27.39 -92.06 baw 1200 62.24 46.98 28.94 -24.52 -53.50 baw 1201 66.94 36.90 18.23 -44.88 -72.77 range 54.61-71.44 40.78-62.11 4.46-29.16 mean 63.70 49.43 19.03 lsd (0.01) 6.25 cv (%) 8.81 shoot lengthshoot lengthshoot lengthshoot length shoot length of 30 days old seedling was significantly influenced by influenced by the interaction effect of soil salinity levels and wheat genotypes (table 2). the shoot length was found to be higher at control (with a range from 33.30 cm in baw 1193 to 53.00 cm in baw 1182 and a mean of 41.54 cm), moderate at moderate stress (ranging from 24.20 cm in bari gom 25 to 38.97 cm sourav with a mean of 29.92 cm) and lower at higher soil salinity stress (with a range from 17.50 cm in baw 1197 to 38.90 cm in sourav and a mean of 23.63 cm). the shoot length was found to be reduced with the increment of soil salinity stress but the degree of reduction was not similar for all wheat genotypes. 57 influence of soil salinity on seedling growth of wheat table 2. shoot length of different wheat genotypes as influenced by salinity levels wheat genotypes shoot length (cm) % change over control at 6 ds m-1 % change over control at 12 ds m-1 control saline (6 ds m-1) saline (12 ds m-1) sourav 40.50 38.97 38.90 -3.77 -3.95 gourav 38.00 34.03 30.80 -10.44 -18.94 shatabdi 35.40 32.13 26.80 -9.24 -24.29 sufi 36.60 28.70 24.50 -21.58 -33.06 bijoy 36.60 25.40 22.00 -30.60 -39.89 prodip 36.80 24.60 21.00 -33.15 -42.93 bari gom-25 40.17 24.20 21.90 -39.75 -45.48 bari gom-26 39.07 26.20 21.70 -32.94 -44.45 bari gom-27 40.50 27.40 22.10 -32.34 -45.43 bari gom-28 45.50 29.00 22.20 -36.26 -51.20 baw 1177 44.50 31.40 27.40 -29.43 -38.42 baw 1182 53.00 35.40 24.60 -33.20 -53.58 baw 1183 42.90 34.20 22.90 -20.27 -46.62 baw 1184 41.80 30.30 28.10 -27.51 -32.77 baw 1185 43.20 36.60 28.20 -15.27 -34.72 baw 1186 47.37 38.30 27.80 -19.14 -41.31 baw 1187 39.40 31.67 23.00 -19.61 -41.62 baw 1189 44.30 32.90 20.50 -25.73 -53.72 baw 1190 43.50 29.50 24.60 -32.18 -43.44 baw 1191 40.50 26.80 19.60 -33.82 -51.60 baw 1192 41.67 27.20 19.50 -34.72 -53.20 baw 1193 33.30 26.13 18.80 -21.53 -43.54 baw 1194 37.70 28.00 18.70 -25.72 -50.39 baw 1195 40.50 30.10 21.10 -25.67 -47.90 baw 1196 50.57 29.10 24.77 -42.45 -51.01 baw 1197 42.60 28.80 17.50 -32.39 -58.92 baw 1198 42.00 25.50 23.90 -39.28 -43.09 baw 1199 42.10 27.63 17.70 -34.37 -57.95 baw 1200 42.70 29.50 23.30 -30.91 -45.43 baw 1201 43.70 28.10 25.10 -35.70 -42.56 range 33.3053.00 24.6038.97 17.5038.90 mean 41.54 29.92 23.63 lsd (0.01) 1.52 cv (%) 8.35 at moderate soil salinity stress, wheat genotypes-sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1184, baw 1189, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw1197, baw 1198, baw1199, baw 1200 and baw1201 showed more than 20% reduction and wheat genotypessourav, gourav, shatabdi, baw 1185, baw 1186 and baw 1187 showed less than 20% reduction in shoot length compared to control. at higher soil salinity stress, wheat genotypesbari gom 28, baw 1182, baw 1189, baw 1191, baw 1192, baw 1194, baw 1196, baw 1197 and baw 1199 showed more than 50% reduction and others wheat genotypes showed less than 50% reduction in shoot length compared to control. 58 sultana et al. root lengthroot lengthroot lengthroot length root length of 30 days old seedling was significantly influenced by the interaction effect of soil salinity levels and wheat genotypes (table 3). the root length was found to be higher at control (with a range from 12.57 cm in sufi to 23.20 cm in baw 1185 and a mean of 17.03 cm), moderate at moderate stress (ranging from 8.03 cm in baw 1194 to 16.23 cm in gourov with a mean of 12.99 cm) and lower at higher soil salinity stress (with a range from 6.33 cm in baw 1200 to 13.70 cm in shatabdi and a mean of 9.44 cm). table 3. root length of different wheat genotypes as influenced by salinity levels wheat genotypes root length (cm) % change over control at 6 ds m-1 % change over control at 12 ds m-1 control saline (6 ds m-1) saline (12 ds m-1) sourav 14.13 13.70 11.50 -3.04 -18.61 gourav 14.00 16.23 11.20 +15.93 -20.00 shatabdi 12.84 13.20 13.70 +2.80 +6.70 sufi 12.57 12.70 8.33 +1.03 -33.73 bijoy 18.00 14.60 8.43 -18.89 -53.17 prodip 18.00 14.50 12.20 -19.44 -32.22 bari gom-25 17.80 12.60 11.28 -29.21 -36.62 bari gom-26 16.10 13.00 11.60 -19.25 -27.95 bari gom-27 17.30 13.80 9.60 -20.23 -44.51 bari gom-28 16.30 12.70 11.50 -22.09 -29.45 baw 1177 19.00 14.00 12.00 -26.32 -36.84 baw 1182 14.80 12.80 9.70 -13.51 -34.46 baw 1183 19.60 14.50 11.10 -26.02 -43.37 baw 1184 18.00 10.40 11.70 -42.22 -35.00 baw 1185 23.20 16.10 12.00 -30.60 -48.28 baw 1186 18.50 8.30 6.73 -55.14 -63.62 baw 1187 21.30 11.40 7.83 -46.48 -63.24 baw 1189 16.00 8.13 7.20 -49.19 -55.00 baw 1190 18.60 9.83 8.50 -47.15 -54.30 baw 1191 17.30 13.10 6.90 -24.27 -60.12 baw 1192 18.03 13.30 6.53 -26.23 -63.78 baw 1193 16.40 14.40 7.60 -12.19 -53.66 baw 1194 16.30 8.03 7.30 -50.74 -55.21 baw 1195 16.30 14.30 8.00 -12.27 -50.92 baw 1196 17.30 11.40 10.20 -34.10 -41.04 baw 1197 14.90 15.00 8.80 +0.67 -40.94 baw 1198 17.20 11.50 9.53 -33.14 -44.59 baw 1199 18.00 15.60 7.70 -13.33 -57.22 baw 1200 16.00 14.50 6.33 -9.38 -60.44 baw 1201 17.40 16.10 8.30 -7.47 -52.30 range 12.5723.20 8.03-16.23 6.33-13.70 mean 17.03 12.99 9.44 lsd (0.01) 2.68 cv (%) 12.71 59 influence of soil salinity on seedling growth of wheat the root length was found to be reduced with the increment of soil salinity stress but the degree of reduction was not similar for all wheat genotypes. at moderate soil salinity stress, wheat genotypesbari gom 25, bari gom 27, bari gom 28, baw 1177, baw 1183, baw 1184, baw 1185, baw 1186, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw 1194, baw 1196 and baw 1198 showed more than 20% reduction and wheat genotypessourav, bijoy, prodip, bari gom 26, baw 1182, baw 1193, baw 1195, baw 1199, baw 1200 and baw 12001 showed less than 20% reduction in germination index compared to control except gourov, sufi and baw 1197 in which root length was even increased. at higher soil salinity stress, wheat genotypesbijoy, baw 1186, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw 1193, baw 1194, baw 1195, baw 1199, baw 1200 and baw 1201 showed more than 50% reduction and others wheat genotypes showed less than 50% reduction in root length compared to control. shoot dry weightshoot dry weightshoot dry weightshoot dry weight shoot dry weight of 30 days old seedling was significantly influenced by influenced by the interaction effect of soil salinity levels and wheat genotypes (table 4). the shoot dry weight was found to be higher at control (with a range from 2.34 mg in sufi to 5.01 mg in baw 1200 and a mean of 3.33 mg), moderate at moderate stress (ranging from 0.64 mg in bari gom 26 to 3.18 mg in sourav with a mean of 1.40 mg) and lower at higher soil salinity stress (with a range from 0.32 mg in baw 1197 to 1.31 mg in baw 1201 and a mean of 0.67 mg). shoot dry weight was found to be reduced with the increment of soil salinity stress but the degree of reduction was not similar for all wheat genotypes. table 4. shoot dry weight of different wheat genotypes as influenced by salinity levels wheat genotypes shoot dry weight (mg) % change over control at 6 dsm-1 % change over control at 12 dsm-1 control saline (6 dsm-1) saline (12 dsm-1) sourav 2.73 3.18 1.27 +16.48 -53.47 gourav 2.70 1.41 0.93 -47.77 -65.55 shatabdi 2.62 1.45 1.03 -44.65 -60.68 sufi 2.34 1.13 0.70 -51.70 -70.08 bijoy 3.29 1.30 0.63 -60.48 -80.85 prodip 3.17 0.88 0.60 -72.24 -81.07 bari gom-25 3.23 0.82 0.48 -74.61 -85.13 bari gom-26 2.68 0.64 0.45 -76.11 -83.21 bari gom-27 2.73 0.78 0.38 -71.42 -86.08 bari gom-28 2.72 1.01 0.32 -62.86 -88.23 baw 1177 3.44 1.46 0.65 -57.55 -81.10 baw 1182 3.73 1.29 0.58 -65.42 -84.45 baw 1183 4.46 1.45 0.49 -67.48 -89.01 baw 1184 2.86 1.23 1.17 -56.99 -59.09 baw 1185 2.57 1.41 1.31 -45.14 -49.02 baw 1186 3.99 2.84 1.02 -28.82 -74.43 60 sultana et al. wheat genotypes shoot dry weight (mg) % change over control at 6 dsm-1 % change over control at 12 dsm-1 control saline (6 dsm-1) saline (12 dsm-1) baw 1187 2.86 1.74 0.76 -39.16 -73.42 baw 1189 2.50 1.78 0.35 -28.80 -86.00 baw 1190 3.79 1.03 0.44 -72.82 -88.39 baw 1191 2.80 1.22 0.41 -56.43 -85.35 baw 1192 3.37 1.27 0.36 -62.31 -89.31 baw 1193 3.13 1.65 0.40 -47.28 -87.22 baw 1194 3.98 1.36 0.36 -65.83 -90.95 baw 1195 2.77 1.27 0.49 -54.15 -82.31 baw 1196 3.32 1.30 0.82 -60.84 -75.30 baw 1197 3.68 1.37 0.32 -62.77 -91.30 baw 1198 3.88 1.40 0.75 -63.92 -80.67 baw 1199 4.49 1.27 0.56 -71.71 -87.53 baw 1200 5.01 1.59 0.91 -68.26 -81.83 baw 1201 5.23 1.50 1.13 -71.32 -78.39 range 2.34-5.01 0.64-3.18 0.32-1.13 mean 3.33 1.40 0.67 lsd (0.01) 0.087 cv (%) 8.35 at moderate soil salinity stress, wheat genotypes-sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1184, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw1197, baw 1198, baw1199, baw 1200 and baw1201 showed more than 50% reduction and wheat genotypesgourav, shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 showed less than 50% reduction in shoot dry weight compared to control except sourav, in which shoot dry weight was even increased.at higher soil salinity stress, wheat genotypesbijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1189, baw 1190, baw 1191, baw 1192, baw 1193, baw 1194, baw 1195, baw 1197, baw 1198, baw 1199 and baw 1200 showed more than 80% reduction and others wheat genotypes showed less than 80% reduction in shoot dry weight compared to control. root dry weightroot dry weightroot dry weightroot dry weight root dry weight of 30 days old seedling was significantly influenced by influenced by the interaction effect of soil salinity levels and wheat genotypes (table 5). the root dry weight was found to be higher at control (with a range from 0.55 mg in baw 1196 to 1.64 mg in baw 1201 and a mean of 0.95 mg), moderate at moderate stress (ranging from 0.24 mg in baw 1177 to 0.93 mg in baw 1185 with a mean of 0.39 mg) and lower at higher soil salinity stress (with a range from 0.05 mg in baw 1194 to 0.30 mg in baw 1186 and a mean of 0.20 mg). 61 influence of soil salinity on seedling growth of wheat table 5. root dry weight of different wheat genotypes as influenced by salinity levels wheat genotypes root dry weight (mg) % change over control at 6 dsm-1 % change over control at 12 dsm-1 control saline (6 dsm-1) saline (12 dsm-1) sourav 0.67 0.69 0.46 +2.98 -31.34 gourav 0.77 0.42 0.29 -45.45 -62.34 shatabdi 0.79 0.36 0.47 -54.43 -40.51 sufi 0.64 0.26 0.26 -59.37 -59.37 bijoy 1.14 0.35 0.24 -69.29 -78.94 prodip 0.88 0.26 0.23 -70.45 -73.86 bari gom-25 0.77 0.28 0.17 -63.63 -77.92 bari gom-26 0.82 0.25 0.27 -69.51 -67.07 bari gom-27 0.73 0.25 0.12 -65.75 -83.56 bari gom-28 0.75 0.26 0.15 -65.33 -80.00 baw 1177 1.28 0.24 0.28 -81.25 -78.12 baw 1182 1.08 0.33 0.09 -69.44 -91.66 baw 1183 1.15 0.45 0.16 -60.87 -86.08 baw 1184 1.27 0.40 0.32 -68.50 -74.80 baw 1185 1.71 0.93 0.27 -45.61 -84.210 baw 1186 1.59 0.90 0.30 -43.39 -81.13 baw 1187 0.92 0.40 0.19 -56.52 -79.34 baw 1189 0.71 0.52 0.09 -26.76 -87.32 baw 1190 1.02 0.29 0.16 -71.56 -84.31 baw 1191 0.94 0.43 0.12 -54.25 -87.23 baw 1192 0.72 0.31 0.12 -56.94 -83.33 baw 1193 0.81 0.47 0.09 -41.97 -88.88 baw 1194 0.85 0.25 0.05 -70.58 -94.11 baw 1195 0.72 0.33 0.12 -54.16 -83.33 baw 1196 0.55 0.34 0.20 -38.18 -63.63 baw 1197 0.86 0.33 0.09 -61.62 -89.53 baw 1198 0.90 0.27 0.17 -70.00 -81.11 baw 1199 1.09 0.45 0.12 -58.71 -88.99 baw 1200 0.87 0.50 0.15 -42.52 -82.75 baw 1201 1.64 0.45 0.18 -72.56 -89.02 range 0.55-1.64 0.24-0.93 0.05-0.30 mean 0.95 0.39 0.20 lsd (0.01) 0.025 cv (%) 7.76 shoot dry weight was found to be reduced with the increment of soil salinity stress but the degree of reduction was not similar for all wheat genotypes. at moderate soil salinity stress, wheat genotypesshatabdi, sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, 62 sultana et al. bari gom 28, baw 1177, baw 1182, baw 1183, baw 1184, baw 1187, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw1197, baw 1198, baw 1199 and baw1201 showed more than 50% reduction and wheat genotypesgourav, baw 1185, baw 1186, baw 1187, baw 1189, baw 1193, baw 1196 and baw 1200 showed less than 50% reduction in root dry weight compared to control except sourav, in which root dry weight was even increased. at higher soil salinity stress, wheat genotypesbari gom 27, bari gom 28, baw 1182, baw 1183, baw 1185, baw 1186, baw 1189, baw 1190, baw 1191, baw 1192, baw 1193, baw 1194, baw 1195, baw 1197, baw 1198, baw 1199, baw 1200 and baw 1201 showed more than 80% reduction and others wheat genotypes showed less than 80% reduction in root dry weight compared to control. seedling dry weightseedling dry weightseedling dry weightseedling dry weight seedling dry weight of 30 days old seedling was significantly influenced by influenced by the interaction effect of soil salinity levels and wheat genotypes (table 6). the seedling dry weight was found to be higher at control (with a range from 3.00 mg in sufi to 6.87 mg in baw 1201 and a mean of 4.34 mg), moderate at moderate stress (ranging from 0.94 mg in bari gom 26 to 4.34 mg in baw 1185 with a mean of 1.84 mg) and lower at higher soil salinity stress (with a range from 0.41 mg in baw 1194 to 1.73 mg in sourav and a mean of 0.89 mg). seedling dry weight was found to be reduced with the increment of soil salinity stress but the degree of reduction was not similar for all wheat genotypes. at moderate soil salinity stress, wheat genotypessufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1184, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw1197, baw 1198, baw 1199, baw 1200 and baw1201 showed more than 50% reduction and wheat genotypesgourav, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 showed less than 50% reduction in seedling dry weight compared to control except sourav, in which seedling dry weight was even increased. at higher soil salinity stress, wheat genotypesprodip, bijoy, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1189, baw 1190, baw 1191, baw 1192, baw 1193, baw 1194, baw 1195, baw 1197, baw 1198, baw 1199, baw 1200 and baw 1201 showed more than 80% reduction and others wheat genotypes showed less than 80% reduction in seedling dry weight compared to control. at higher soil salinity stress sourov, shatabdi, sufi, baw1184, baw1186, baw1187 and baw11896 showed comparatively lower reduction in seedling dry weight. in the present study, all parameters were affected due to salt stress. with increasing salt concentration in the environment for germination, shoot and root length and dry weight were reduced significantly. garciarrubio et al. (2003) and datta et al. (2009) were also found the same result. it has been reported that salinity stress significantly reduced net photosynthetic rates, increased energy losses for salt exclusion mechanism, largely decreased nutrient mobilization, suspending the cell division and enlargement and finally reduced plant growth (meiri and poljakoff-mayber, 1970, long and baker, 1986 and seeman and sharkey, 1986). salinity affects the seedling growth of plants (tezara et al., 2003, rahman and kayani, 1988) by slow or less mobilization of reserve foods (kayani et al., 1990), suspending the cell division, enlargement (meiri and apoljakoff-mayber, 1970) and injuring hypocotyls (assadian and miyamoto, 1987). 63 influence of soil salinity on seedling growth of wheat table 6. seedling dry weight of different wheat genotypes as influenced by salinity levels wheat genotypes seedling dry weight (mg) % change over control at 6 dsm-1 % change over control at 12 dsm-1 control saline (6 dsm-1) saline (12 dsm-1) sourav 3.40 3.87 1.73 +13.82 -49.12 gourav 3.49 1.83 1.27 -47.56 -63.61 shatabdi 3.42 1.87 1.50 -45.32 -56.14 sufi 3.00 1.36 0.97 -54.66 -67.66 bijoy 4.43 1.66 0.90 -62.52 -79.68 prodip 4.05 1.15 0.84 -71.60 -79.25 bari gom-25 3.68 1.10 0.66 -70.11 -82.07 bari gom-26 3.50 0.94 0.72 -73.14 -79.43 bari gom-27 3.47 1.04 0.50 -70.03 -85.59 bari gom-28 3.47 1.28 0.68 -63.11 -80.40 baw 1177 4.73 1.20 0.94 -74.63 -80.13 baw 1182 4.83 1.63 0.68 -66.25 -85.92 baw 1183 5.61 1.91 0.65 -65.95 -88.41 baw 1184 4.13 1.63 1.50 -60.53 -63.68 baw 1185 5.95 4.34 1.58 -27.06 -73.45 baw 1186 5.50 3.75 1.32 -31.82 -76.00 baw 1187 3.79 2.15 0.95 -43.27 -74.93 baw 1189 3.22 2.31 0.44 -28.26 -86.33 baw 1190 4.70 1.32 0.61 -71.91 -87.02 baw 1191 3.83 1.65 0.54 -56.92 -85.90 baw 1192 4.29 1.58 0.49 -63.17 -88.57 baw 1193 3.95 2.12 0.50 -46.33 -87.34 baw 1194 4.84 1.61 0.41 -66.74 -91.53 baw 1195 3.50 1.60 0.62 -54.28 -82.28 baw 1196 3.88 1.64 1.02 -57.73 -73.71 baw 1197 4.57 1.71 0.41 -62.58 -91.03 baw 1198 4.78 1.18 0.92 -75.31 -80.75 baw 1199 5.53 1.73 0.68 -68.72 -87.70 baw 1200 5.89 2.09 1.07 -64.52 -81.83 baw 1201 6.87 1.95 1.31 -71.62 -80.93 range 3.00-6.87 0-94-4.34 0.41-1.73 mean 4.34 1.84 0.89 lsd (0.01) 0.025 cv (%) 2.28 the same authors found that the reduction in root and shoot deve-lopment may be due to toxic effects of the higher level of nacl concentration as well as unbalanced nutrient uptake by the seedlings. high level of salinity may have also inhibit the root and shoot elongation due to slowing down the water uptake for overall osmotic adjustments of the plant body under high salt stress condition. salt stress result in a considerable decrease in the fresh and dry weights of root and shoot (chartzoulakis & klapaki 2000, parida and das, 2005). but the adverse effect on seedling dry weight was different in different wheat genotypes which indicate different 64 sultana et al. sensitivity of wheat genotypes to salt stress. singh (2008) also found differential sensitivity of wheat genotypes based on seedling growth in their study and karim et al (1992) suggested that seedling growth is one of the most important characters for screening salt tolerance at early stage of growth. salt tolerance index salt tolerance index salt tolerance index salt tolerance index based on sbased on sbased on sbased on seedling dry weighteedling dry weighteedling dry weighteedling dry weight salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) at 6 ds m-1 artificial saline soil is presented in fig. difference in salt tolerance among the wheat genotypes. wheat genotypes shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 showed more than 0.5 sti and sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1184, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw 1201 provided less than 0.50 sti. fig. 2. salt tolerance index of different wheat genotypes based on seedling dry 6 ds m-1 artificial saline soil (vertical bar indicates lsd salt tolerance index based on ssalt tolerance index based on ssalt tolerance index based on ssalt tolerance index based on seedling dry weighteedling dry weighteedling dry weighteedling dry weight salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) at 12 ds m-1 artificial saline soil is presented in fig. difference in salt tolerance among the wheat genotypes. wheat genot shatabdi, sufi and baw 1184 showed more than 0.3 sti and bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1185, baw 1186, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw sensitivity of wheat genotypes to salt stress. singh et al., (2000) and moud and maghsoudi ferential sensitivity of wheat genotypes based on seedling growth in their (1992) suggested that seedling growth is one of the most important characters for screening salt tolerance at early stage of growth. eedling dry weighteedling dry weighteedling dry weighteedling dry weight grown at 6 ds mgrown at 6 ds mgrown at 6 ds mgrown at 6 ds m----1111 artificial saline soilartificial saline soilartificial saline soilartificial saline soil salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) line soil is presented in fig. 2. these sti values indicated a wi difference in salt tolerance among the wheat genotypes. wheat genotypessourav, gourav, shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 showed more than 0.5 sti and sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari baw 1177, baw 1182, baw 1183, baw 1184, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw fig. 2. salt tolerance index of different wheat genotypes based on seedling dry weight grown at soil (vertical bar indicates lsd value). eedling dry weighteedling dry weighteedling dry weighteedling dry weight grown at 12 ds mgrown at 12 ds mgrown at 12 ds mgrown at 12 ds m----1111 artificial saline soilartificial saline soilartificial saline soilartificial saline soil salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) line soil is presented in fig.3. these sti values indicated a wide difference in salt tolerance among the wheat genotypes. wheat genotypessourav, gourav, shatabdi, sufi and baw 1184 showed more than 0.3 sti and bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1185, baw 1186, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw moud and maghsoudi ferential sensitivity of wheat genotypes based on seedling growth in their (1992) suggested that seedling growth is one of the most important salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) 2. these sti values indicated a wide sourav, gourav, shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 showed more than 0.5 sti and sufi, bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari baw 1177, baw 1182, baw 1183, baw 1184, baw 1190, baw 1191, baw 1192, baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw weight grown at salt tolerance index (sti) of thirty wheat genotypes based on seedling dry weight (30 days old) 3. these sti values indicated a wide sourav, gourav, shatabdi, sufi and baw 1184 showed more than 0.3 sti and bijoy, prodip, bari gom 25, bari gom 26, bari gom 27, bari gom 28, baw 1177, baw 1182, baw 1183, baw 1185, baw 1186, baw 1187, baw 1189, baw 1190, baw 1191, baw 1192, baw influence of soil salinity on seedling growth of wheat 1193, baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw 1201 provided less than 0.3. fig.3. salt tolerance index of different wheat genotypes based on seedling dry weight grown at 12 ds m-1 artificial saline soil (vertical bar indic salt tolerance index (sti) also indicated a wide difference in salt tolerance among the wheat genotypes. sourav, gourav, shatabdi, baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 were more salt tolerance while baw 1177, baw 1190 and baw 1198 showed greater salt sensitivity than the other wheat genotypes at 6 ds m sourav, gourav, shatabdi, sufi and baw 1 baw 1190, baw 1192, baw 1194 and baw 97 provided greater stress sensitivity among the testing wheat genotypes. considering both saline stress sourav, gourav and shatabdi were found to be salt tolerant and baw 1190 was saline sensitive wheat genotypes. ashraf m. 1999. interactive effect of salt (nacl) and nitrogen form of growth, water relations and photosynthesis capacity of sunflower 513. assadian n. w. and s. miyamoto. 1987. salt effects on alfalfa seedling emergence. agron. j.79: 710-714. boubaker m. 1996. salt tolerance of durum wheat cultivars during germination and early seedling growth. agric. medit. 126:32-39. influence of soil salinity on seedling growth of wheat baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw fig.3. salt tolerance index of different wheat genotypes based on seedling dry weight grown at soil (vertical bar indicates lsd value). conclusionconclusionconclusionconclusion salt tolerance index (sti) also indicated a wide difference in salt tolerance among the wheat , baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 were more salt tolerance while baw 1177, baw 1190 and baw 1198 showed greater salt sensitivity than the other wheat genotypes at 6 ds m-1. however, at 12 ds m sourav, gourav, shatabdi, sufi and baw 1184 showed more salt tolerance and baw 1183, baw 1190, baw 1192, baw 1194 and baw 97 provided greater stress sensitivity among the testing wheat genotypes. considering both saline stress sourav, gourav and shatabdi were 90 was saline sensitive wheat genotypes. referencesreferencesreferencesreferences ashraf m. 1999. interactive effect of salt (nacl) and nitrogen form of growth, water relations and photosynthesis capacity of sunflower (helianthus annus l.). ann. appl. biol. 135: 509 w. and s. miyamoto. 1987. salt effects on alfalfa seedling emergence. agron. j.79: boubaker m. 1996. salt tolerance of durum wheat cultivars during germination and early seedling 39. 65 baw 1194, baw 1195, baw 1196, baw 1197, baw 1198, baw 1199 and baw fig.3. salt tolerance index of different wheat genotypes based on seedling dry weight grown at salt tolerance index (sti) also indicated a wide difference in salt tolerance among the wheat , baw 1185, baw 1186, baw 1187, baw 1189 and baw 1193 were more salt tolerance while baw 1177, baw 1190 and baw 1198 showed . however, at 12 ds m-1, 184 showed more salt tolerance and baw 1183, baw 1190, baw 1192, baw 1194 and baw 97 provided greater stress sensitivity among the testing wheat genotypes. considering both saline stress sourav, gourav and shatabdi were ashraf m. 1999. interactive effect of salt (nacl) and nitrogen form of growth, water relations and l.). ann. appl. biol. 135: 509w. and s. miyamoto. 1987. salt effects on alfalfa seedling emergence. agron. j.79: boubaker m. 1996. salt tolerance of durum wheat cultivars during germination and early seedling 66 sultana et al. chartzoulakis k. and g. klapaki. 2000. response of two green house pepper hybrids to nacl salinity during different growth stages. sci. hortic. 86: 247–260. datta j. k., s. nag, a. banerjee. and n. k. mondal. 2009. impact of salt stress on five varieties of wheat (triticum aestivum l.) cultivars under laboratory condition. j. appl. sci. environ. 13(3): 93 – 97. garciarrubio a., j. p. leg aria and a. a. covarrubias. 2003. abscisic acid inhibits germination of mature arabidopsis seeds by limiting the availability of energy and nutrients. planta 2:182187. goudarzi, m. and h. pakniyat. 2008. evaluation of wheat cultivars under salinity stress based on some agronomic and physiological traits. j. agri. soc. sci. 4: 81–4. greenway h. and r. munns. 1980. mechanism of salt tolerance in non-halophytes. ann. rev. plant physiol. 31. 149-190. gul b. and d. j. weber. 1999. effect of salinity, light, and temperature on germination in allenrolfea occidentalis. can. j. bot. 77:240246. karim m. a., n. utsunomiya and s. shigenaga. 1992. effect of sodium chloride on germination and growth of hexaploid triticale at early seedling stage. japan j. crop sci. 61 (2):279284. kayani s. a., h. h. naqvi and i. p. ting. 1990. salinity effects on germination and mobilization of reserves in jojoba seed. crop sci. 30 (3): 704-708. long s. p. and n. r. baker. 1986. saline terrestrial environments. in: n. r. baker and s. p. long (eds). photosynthesis in contrasting environments. pp. 63-102. elsevier, amsterdam. meiri, a. and a. poljakoff-mayber. 1970. effect of various salinity regimes on growth, leaf expansions and transpiration rate of bean plants. plant soil sci. 109: 26-34. moud a. m. and k. maghsoudi. 2008. salt stress effects on respiration and growth of germinated seeds of different wheat (triticum aestivum l.) cultivars. world j. agril. sci. 4(3): 351-358. parida a. k. and a. b. das., 2004. salt tolerance and salinity effect on plants: a review. ecotoxicol. and environ. safely. 60: 324–349. rahman m. and s. a. kayani. 1988. effects of chloride type of salinity on root growth and anatomy of corn (zea mays l.). biologia. 34 (1): 123-131. rhoades j. d., f. chanduvi and s. lesch. 1999. soil salinity assessment; methods and interpretation of electrical conductivity measurements. p: 5-6. seeman j. r. and j. d. sharkey. 1986. salinity and nitrogen effects on photosynthesis, ribulose1,5 bisphosphate carboxylase and metabolites pool size in phaseolus vulgaris l. plant physiol. 82: 555-560. singh a. k., v. prakash and e. v. d. sastry. 2000. effect of salinity stress on seed germination and seeding growth of wheat. agric. sci. digest. 20(2): 96-98. tezara w., d. martinez, e. rengifo and a. herrera. 2003. photosynthetic response of the tropical spiny shrub lycium nodosum (solanaceae) to drought, soil salinity and saline spray. annals bot.. 92: 757-765. bangladesh agron. j. 2017, 20 (1): 13-24 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 under awd irrigation system mka bhuiyan*, md. mostofa mahbub, lutfun nahar, md. zakaria ibne baki bangladesh rice research institure, joydebpur, gazipur-1701, bangladesh corresponding author: bhuiyan072003@yahoo.com key wards: weed management, herbicide, weed abundance and grain yield abstract experiment was carried out at the agronomy field of bangladesh rice research institute, gazipur, during the period from december 2014 to may 2015 to investigate the response of different levels of n and methods of weeding on weed abundance and grain yield of brri hybrid dhan3 under alternate wetting and drying (awd) irrigation condition. the treatments consisted of five n levels viz.,0, 60, 120,180 and 240 kg n ha-1 and four different weed control methods viz., pre-emergence herbicide followed by 1hw, pre-emergence followed by post emergence herbicide, weed free by 3 hand weedings and unweeded (control). the experiment was laid out in factorial rcb design with three replication. pre-emergence application of prefer 18wp (bensulfuran methyl + acetachlor) and post emergence herbicide dhaman 300wp (bispyribac sodium 18% + bensulfuran methyl 12%) followed by one hand weeding effectively control all weeds (78-93%). in the experimental field, sedges and grass weeds were highly dominant over treatments. based on summed dominance ratio (sdr), the most dominant weed species could be arranged in the order of echinochloa crus-galli > scirpus juncoides > cynodon dactylon > cyperus difformis > marselia minuta > monochoria vaginalis. interaction of nitrogen levels and weeding methods had significant response on yield and yield components of hybrid rice. the highest (7.61 t ha-1) grain yield was obtained from the combination @ 180 kg n ha-1 with weed free treatments. comparable higher grain yield was obtained from the combination of pre emergence herbicide of bensulfuranm methyl + acetachlor) + one hand weeding with 180 kg n ha (7.48 t ha-1) and the combination of pre + post-emergence herbicide (bispyribac sodium 18% + bensulfuran methyl 12%) with 180 kg n ha-1 (7.56t ha-1). the estimated optimum dose of nitrogen for pre eh, post eh and 3hw (weed free) were 173, 189.1 and 189.4 kg n ha-1 respectively for brri hybrid dhan3 under awd irrigation system. introduction rice (oryza sativa l.) is one of the most important cereal crops in the world. in bangladesh, the area and production of hybrid rice in boro season were about 6.36 lac hectares and 30.09 lac metric tons, respectively (ais, 2015). the population of bangladesh is still growing by two million every year and may increase by another 30 million over the next 20 years. thus, bangladesh will require about 27.26 million tons of rice for the year of 2020. but the average yield of rice is 4.50 t ha-1 in bangladesh, whereas the average rice yield in china, japan and korea is about 6.0 6.50 t ha-1 (brri, 2016). fertilization and weeding practices are very important factors for harvesting potential yield in rice. attempts should also be taken to increase the yield per unit area through use of comparatively high yielding varieties. 14 bhuiyan et al. the efficient n management can increase crop yield and reduce production cost. inadequate and improper applications of n are now considered one of the major reasons for low yield of rice in bangladesh. weeds pose a major threat for increasing rice productivity. uncontrolled weed growth caused significant loss of grain yield of rice. any delay in weeding will lead to increased weed biomass as a result drastic reduction in yield. moreover weed management in alternate wetting and drying (awd) irrigation system revolved around grass weeds, predominantly echinoachloa sp. awd reduced broadleaf weed pressure and increase grass type weed and enhance overall weed growth and development which compete with rice and reduce yield. so, appropriate weed management strategies should be undertaken in awd irrigation systems this study was undertaken to evaluate the yield response of brri hybrid dhan3 to different nitrogen levels and weed control methods under awd irrigation system. materials and methods the field studies were conducted during december 2014 to may 2015 at the experiment site of bangladesh rice research institute (brri) farm, gazipur situated at 24099' north latitude and 90040' east longitude. the soil of the experimental site was clay loam of shallow brown terrace under madhupur tract (aez 28), the experimental field classified as a chhiata clay loam, hyperthermic vertic endoaquept. the initial chemical properties of the experimental site was presented in table 1.the planting crop was brri hybrid dhan3. the experiment consisted of two factors: a. n level viz., 0. 60, 120, 180 and 240 kg ha-1. b: weed control method viz., pre emergence herbicide + 1hw, pre emergence + post emergence herbicide, weed free by hand weeding and un weeded (control). details of weeding treatments were presented in table2. thirty days old seedlings were uprooted and transplanted on well puddled plots. the experiment was laid out in rcb design with three replications. the experimental plots were fertilized with tsp, mop, gypsum and zine @ 127,120,112 and 15 kg ha-1, respectively according to brri recommended dose. irrigation was done by awd irrigation system. in awd treatment, pvc tubes (25 cm long and 10 cm in diameter) were installed to a depth of 15 cm below soil surface as described by tuong et al. (2005).to obtained grain yield in individual plots six m2 area was selected. after sun drying moisture was adjusted at 14% and weighted and converted to t ha-1. one meter square area was selected at random in each plot for counting tiller and panicle number. yield characters were calculated by selected 2x2 hill diagonally (12 hills) from each plot. the grains and sterile spikelets were separated by a seed sorter (kiya seisakusho ldt, model 1973, tokyo, japan). after separation, the grains and sterile spikelets were counted by an automatic counter (nagoya, model dc 1-0, japan). then the numbers of grain panicle-1, weight of 1000grains was measured at 12% moisture and sterility (%) was calculated. the nitrogen use efficiency can be defined as the maximum economic yield produced per unit of nitrogen applied, absorbed or utilized by the plant to produce grain and straw. however, nitrogen use efficiency was determining as agronomic efficiency as described by fageria and baligar, 2001. agronomic efficiency (ae) = gf gu /na = kg kg-1 where, gf is the grain yield in the fertilized plot (kg), gu is the grain yield in the unfertilized plot (kg), and na is the quantity of nutrient applied (kg). 15 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 optimization of n dose in different weed control methods the optimum n dose for brri hybrid dhan3 in different weed control methods was determined by regression the corresponding grain yield with the n rates: y = a + bn+ cn.. where, y is rice yield (t/ha), n is nitrogen dose (kg/ha), a is intercept (estimated yield without n application), b and c are coefficients, respectively (saleque et al., 2004). differentiating y with respect to n of the eqn. gives the nitrogen dose for the maximum yield. the estimated nitrogen dose for maximum yield n= -b/2c. weed biomass and number of weeds were assessed at 50 dat from all experimental plots. random samples were taken from within each plot using a 1m x 1m quadrate (kim and moody, 1983). weed species collected from within each quadrate were identified, listed and counted. collected weeds were washed, sorted by species, dried at 70o c to constant weight and then weighed. for weed identification the nomenclature of moody (1989) was used. data were recorded included weed type and species, number of weeds and weed biomass etc. summed dominance ratio (sdr) sdr of the weed species was computed using the following equation (janiya and moody, 1989): 2 (rdw) weight dry relative + (rd) density relative sdr relative dry weight (rdw) = 100 weightdrytotal speciesgivenaofweightdry relative density (rd) = 100 densitytotal speciesgivenaofdensity weed control efficiency (wce %) and weed index (wi) was calculated by using subsequent formula according to rao (1985). weed control efficiency (wce) = 100 wc wtwc wc= average weed weight per unit area in weedy check wt= average weed count or dry weed weight per unit area in treated plot higher values of wce indicate greater effectiveness of the herbicide weed index (wi) = 100 yhw ytyhw where, yhw= average yield of the crop in hand weeded, weed free plot or minimum weed competition plot yt= average yield of the crop in plot under other weed control treatments. higher value of weed index indicates lower the yield and lower value of weed index indicate higher the yield. data were analyzed statistically by statistical software crop stat 7.2. analysis of variance and treatments were compared with least significant difference (lsd). correlation and regression were done by microsoft excel program. 16 bhuiyan et al. results and discussion weed growth and weed control efficiency (%) interaction effect of weed management and n levels were not significant on weed number and dry matter weights of weeds but weed control treatments significantly reduced the weed population (m-2) and weed dry matter weight (gm-2) over the control (un weeded) (table 3). higher weed number and biomass were found in unweeded x different n levels and lower in different weed management x n levels treatments. pre emergence herbicide + 1hw and pre emergence herbicide + post emergence herbicide produced minimum number of weed and obtained minimum dry matter weight in different n levels. the weed control efficiency also revealed the superiority of the pre-emergence and post emergence herbicide application + hand weeding. the weed control efficiency of different weed management treatments ranged 78-93%.the present experimental results of weed growth and wce coroborates the findings from akbar et al. (2011) who reported that the herbicide treatments resulted more than 80 % reduction in weed density and 74-87 % decrease in weed dry weight. bhuiyan and gazi (2010) reported that mefenacet + bensulfuron methyl 53%wp @ 594g ai ha-1 lead to higher wce (> 80%) and lowest number and dry weight of weeds which ultimately resulted in higher yield attributes and grain yield of rice. the weed control efficiency of different weed management treatments ranged 78-93%.the similar consequence of results was reported by srinivasan et al., 2007. relative proportions of different weed types the relative proportions of different weed types (broadleaf, grass and sedges) into total weed number and dry biomass on percentage basis are expressed in figure 1. the contribution of grass, sedges and broadleaves were 37-42, 29-36 and 24-28%, respectively in unweeded condition with different n treatments (figure 1a). therefore, grass was the dominant weed species in respect of weed density in unweeded condition (t11-t15). other weed x n management treatments contributed 25-31% grass, 31-45%sedges and 26-36% broadleaves. it seems sedges were not controlled well by different weed management treatments. considering the proportion of weed biomass unweeded treatments contributed more than 40% grass, 2832% sedges and 21-28% broadleaves (figure 1b). other weed x n management treatments contributed 22-33% grass, 28-40% sedges and 25-44% broadleaves. similar consequences of results were reported by khaliq and matloob (2011) in different competition period of weeds in rice. weed composition and summed dominance ratio (sdr) the summed dominance ratio (sdr) is more informative than any single measure in reflecting the contribution of a species in the community. figure 2 represents sdr values in unweeded condition. the effects of weed interfere at 45dat recorded six weed species. the sdr of echinochloa crus-galli was higher followed by scirpus juncoides. based on summed dominance ratio (sdr), the most dominant weed species could be arranged in the order of echinochloa crus-galli > scirpus juncoides > cynodon dactylon > cyperus difformis > marselia minuta > monochoria vaginalis. anwar et al. (2012) observed similar type of findings in aerobic rice system in different weed management systems. 17 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 relationship of weed density, dry weight and weed index with rice grain yield and applied nitrogen weed index is an ideal parameter to judge the effectiveness of weeding treatments. this is an indicator of reduction of crop yield due to presence of weeds in comparison with weed free plot or minimum weed competition plot. the lower weed index indicates higher effectiveness of a weeding treatment/ herbicide. the lowest weed index was obtained with pre emergence herbicide + 1hw and pre emergence herbicide + post emergence herbicide. the weed indexes in unweeded plots were ranged 23-51%. figure 3 showed the relationship between weed index with dry matter weight (figure 3a) and weed dry weight with rice grain yield (figure 3b). relationship of grain yield on weed index showed that the variation of grain yield was 42.42% due to weed index and the relationship was negative and linear. relationship of weed dry matter weight and weed index showed linear relationship, which indicated an increasing weed biomass index that might contributed to lower yield. singh et al. (2008) reported that the application of different herbicide treatments recorded lower weed index and gave similar yield to that of weed free plots. relationship of grain yield and weed number (figure 4a) indicated that the grain yield was significantly dependent on weed number and the relationship was linear and negative. highest significant and negative correlation of grain yield with weed number was calculated where r2 value were 0.532** indicating the need for minimizing weed density to attain optimal rice grain yield. figure 3b also shows the relationship of grain yield with weed dry weight indicating significant negative correlation with grain yield with coefficient of determination of 0.5204**. relationship of weed biomass and nitrogen dose in different weed control methods were quadric in nature (figure 5).this figure indicates after application of a certain n dose weed biomass will not increase linearly. so, the relationship is quadric. optimization of nitrogen dose in different weed control methods the variation of grain yield of brri hybrid dhan3 at different levels of n with different weed control methods was estimated through regression equation (figure 6). the relationship of grain yield of weeding methods and applied nitrogen was quadric. the quadratic regression equation of brri hybrid dhan3 for pre eh, post eh and 3hw were y = -0.00014x2 + 0.04842x + 2.8840, r2= 0.96*, y = -0.00011x2 + 0.04166x + 3.24229, r2= 0.98* and y = -0.0001x2 + 0.0416x + 3.3214, r2= 0.98* respectively. nitrogen treatment accounted about 96,98 and,98% variation in grain yield for different weed control methods of peh, poeh and 3hw respectively. the estimated optimum dose of nitrogen for pre eh post eh and 3hw (weed free) were 173, 189 and 189 kg n ha-1, respectively. yield and yield contributing character grain yield in n treatments were increased with increased n levels upto 180 kg n ha-1 in all weed management treatments (table 4). interaction effect of weed management x n levels on panicle m-2 and 1000grain weight showed insignificant. the individual effect of weed management on panicle m-2 was also insignificant but effect of n management on panicle m-2 was significant.the highest grains panicle-1 (130) was observed in 3hw x n levels @ 180 kg ha-1 while lowest grains panicle-1 (79) in unweeded x control plots. the highest grain yield (7.62 t/ha) was obtained from 3 hw x n levels @ 180kg ha-1 the lowest grain yield (2.59 t ha-1) was observed with unweeded x control n (0 kg ha-1) plots. regression analyses carried out among yield and yield character to understand yield components association with grain yield 18 bhuiyan et al. (figure 7). a relationship between number of panicles m-2 and grain yield was highly significant (p <0.01) and linear, indicated 287 panicles m-2 are optimal to produce a grain yield of 7.61 t ha-1 under the existing experimental conditions. on the other basis of r2, 65.88% variation in grain yield could be accounted by panicle density. similarly the relationship of grain yield with grains panicle-1 and 1000 -grain weight showed highly significant and linear. in regression analysis it is observed that 87.95% variation in grain yield could be accounted by grains panicle1. therefore, the lower yields would be explained by its lower panicle density, grain panicle-1 and 1000 -grain weight. grain yield is also positively and highly correlated with harvest index. on the basis of r2, 60.35% variation in grain yield could be explained by harvest index. gravois and helms (1992) reported that, among different yield components of rice, panicle density had the largest positive direct effect on rice yield. shimul et al. (2015) observed that nitrogen and weed control had significant response on yield and yield components of hybrid rice agronomic efficiency agronomic efficiency was calculated and presented in table 5. interaction effect of weed and n levels significantly varied agronomic efficiency. in unweeded condition agronomic efficiency was in very low range of 4-13. agronomic efficiency was 23 in 3hw with 180kg n ha-1.in highest yield level and agronomic efficiency ranged 23-28 in 120-180 kg n ha-1 with different weed management options. agronomic nitrogen use efficiency varied 15–25 kg grain per kg of applied n depending on season, yield level, and the rate and timing of n application in different rice culture (fageria and baligar, 2001). conclusion from the study it may be concluded that pre emergence application of prefer 18wp (bensulfuran methyl + acetachlor) and post emergence application of dhaman 300wp (bispyribac sodium 18% + bensulfuran methyl 12%) following one hand weeding resulted in better weed control and grain yield of brri hybrid dhan3 under awd irrigation condition. the highest grain yield (7.61 t ha-1) was found from the combination of applying the nitrogen @ 180kg ha-1 and 3 hand weedings. comparable higher grain yield was obtained from the combination of pre emergence herbicide + one hand weeding with 180 kg n ha (7.48 t ha-1) and the combination of pre + post emergence herbicide with 180 kg n ha-1 (7.56t ha-1). table 1. initial soil chemical properties at 0-15 cm soil depth in the experimental plot soil property value soil ph 6.65 organic matter 1.94% total n content 0.08% available phosphorus (p) 10.15 mg kg –1 (0.5 m nahco3 extracted) exchangeable potassium (k) 0.17 meq/100 g soil (neutral 1.0 n nh4oac extracted) available sulfur (s) 20 mg kg –1 [ca(h2po4)2 extracted] available zinc (zn) 2.92 mg kg –1 (0.01n hcl extracted) 19 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 table 2. description of weed control methods weed control methods description name of herbicide dose time of application time of hand weeding pre emergence herbicide (peh) followed by one hand weeding (1hw) prefer 18wp((bensulfuran methyl + acetachlor) 750 g ha-1 4 dat 50dat* pre emergence herbicide (preeh) followed by post emergence herbicide (poeh) prefer 18wp ((bensulfuran methyl acetachlor) fb dhaman 300wp (bispyribac sodium 18% + bensulfuran methyl 12%) 150 g ha-1 4 dat followed by 22 dat un weeded (uw) weed free (wf) by 3 hand weedings 15, 30 and 50dat dat= days after planting table 3. interaction effect of weed control methods and n levels on weed number, dry matter weight, and weed control efficiency (%) of brri hybrid dhan3 during boro 2014-15 treatment weed m-2 (no.) weed dry matter weight (gm-2) *weed control efficiency (%) weed management n levels ( 0 kg ha-1) pre eh+ 1hw 16 4.82 78 pre eh+ post eh 17 4.44 80 un weeded 46 22.87 n levels ( 60 kg ha-1) pre eh+ 1hw 14 2.71 90 pre eh+ post eh 16 2.55 91 un weeded 49 29.44 n levels ( 120 kg ha-1) pre eh+ 1hw 13 2.08 93 pre eh+ post eh 16 2.36 92 un weeded 48 31.25 n levels (180 kg ha-1) pre eh+ 1hw 14 2.11 93 pre eh+ post eh 15 2.21 92 un weeded 48 30.81 n levels ( 240 kg ha-1) pre eh+ 1hw 14 2.23 92 pre eh+ post eh 17 2.64 90 un weeded 46 30.73 lsd(.05) wm 3.11 4.08 n levels ns ns wm x n levels ns ns cv(%) 16.0 47.3 * % weed control efficiency was calculated over no weeding with dry matter weight basis 20 bhuiyan et al. fig. 1. relative proportion of different weed types in total weed density (a) and biomass (b) over different weed management during 2014-15 fig. 2. weed dominance ranking (sdr) in brri hybrid dhan3 in unweeded condition during 2014-15 21 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 fig. 3. a. relationship of weed dry matter weight with weed index. b. dependence of grain yield on weed index fig. 4. relationship between grain yield with weed number and weed dry matter weight fig. 5. relationship of weed biomass and nitrogen dose y = 0.636x + 1.074 r² = 0.944** 0 10 20 30 40 0 20 40 60 w ee d d ry m at te r w ei gh t( g m -2 ) weed index a y = -0.0574x + 5.8812 r² = 0.4241** 0 2 4 6 8 0 20 40 60 g ra in y ie ld (t h a-1 ) weed index b y = -0.0808x + 7.0859 r² = 0.532* 0 1 2 3 4 5 6 7 8 0 20 40 60 g ra in y ie ld (t h a1 ) weed number(m-2) y = -0.0964x + 6.1026 r² = 0.5204* 0 1 2 3 4 5 6 7 8 0 20 40 g ra in y ie ld (t h a1 ) weed dry matter weight(g m-2) a b 22 bhuiyan et al. fig. 6. optimization of nitrogen dose in different weed control methods based on grain yield table 4. interaction effect of weed management and n levels on yield and yield characters of brri hybrid dhan3 treatment panicle m-2 grains panicle-1 1000grain weight(g) grain yield (t ha-1) weed management n levels ( 0 kg ha-1) pre eh+ 1hw 166 85 27.00 2.99 pre eh+ post eh 167 82 26.29 3.31 weed free (3 hw) 177 93 26.43 3.40 un weeded 181 79 26.34 2.59 n levels ( 60 kg ha-1) pre eh+ 1hw 181 79 26.34 2.59 pre eh+ post eh 210 98 27.27 5.28 weed free (3 hw) 215 103 27.05 5.33 un weeded 209 86 26.96 3.37 n levels ( 120 kg ha-1) pre eh+ 1hw 230 102 27.84 6.38 pre eh+ post eh 253 110 27.59 6.40 weed free (3 hw) 227 113 27.23 6.55 un weeded 216 88 26.99 3.39 n levels ( 180 kg ha-1) pre eh+ 1hw 287 126 28.07 7.56 pre eh+ post eh 276 123 27.92 7.48 weed free (3 hw) 285 130 28.01 7.61 un weeded 236 90 27.09 3.68 n levels ( 240 kg ha-1) pre eh+ 1hw 295 105 26.77 6.22 pre eh+ post eh 286 103 26.66 6.65 weed free (3 hw) 300 105 26.87 6.86 un weeded 248 87 26.36 3.87 lsd(0.05) wm ns 3.49 ns 0.31 n levels 22.56 3.90 ns 0.35 wm x n levels ns 7.80 ns 0.69 cv (%) 11.70 4.7 2.30 8.1 y = -0.00014x2 + 0.04842x + 2.88400 r² = 0.96 0 2 4 6 8 0 80 160 240 yi el d ( t h a-1 ) nitrogen (kg ha-1) y = -0.00011x2 + 0.04166x + 3.24229 r² = 0.98 0 2 4 6 8 0 80 160 240 yi el d (t h a-1 ) nitrogen(kg hay = -0.0001x2 + 0.0416x + 3.3214 r² = 0.98 0 2 4 6 8 0 80 160 240 nitrogen(kg hayi el d t h a-1 ) preeh posteh 3hw 23 effect of nitrogen levels and weed management on yield performance of brri hybrid dhan3 fig. 7. relationship of grain yield with yield components by weed management and nitrogen levels table 5. agronomic efficiency of brri hybrid dhan3 as affected by weed management and nitrogen levels interaction weed management nitrogen levels (kg n ha-1) agronomic efficiency pre emergence herbicide+ 1hw 60 35 120 28 180 25 240 13 pre emergence herbicide+ post emergence herbicide 60 33 120 26 180 23 240 14 3 hand weeding 60 32 120 26 180 23 240 14 un weeded 60 13 120 7 180 6 240 4 lsd(0.05) weed management 2.54 n levels 2.54 weed management × n levels 5.08 cv(%) 15.1 y = 0.0323x 2.3706 r² = 0.6588* 0 2 4 6 8 0 100 200 300 400 g ra in y ie ld (t h a-1 ) panicle m-2 y = 0.1111x 5.9522 r² = 0.8795* 0 2 4 6 8 0 50 100 150 g ra in y ie ld (t h a1 ) grains panicle-1 y = 2.2481x 55.728 r² = 0.5205* 0 2 4 6 8 26 27 27 28 28 29 g ra in y ie ld (t h a1 ) 1000 grain weight(g) y = 50.783x 18.808 r² = 0.6035* 0 2 4 6 8 10 0.40 0.45 0.50 0.55 g ra in y ie ld (t h a1 ) harvest index 24 bhuiyan et al. references ais (agricultural information service). (2015). krishi diary (in bangla). agril. inform. ser. khamarbari, farmgate, dhaka, bangladesh. p.13 akbar, n., ehsanullah , j. khawar, m. a. ali. 2011. weed management improves yield and quality of direct seeded rice. ajcs. 5(6): 688-694 anwar, m. p, a. s. juraimi, b. samedani, a. puteh, a. man. 2012. critical period of weed control in aerobic rice. the scientific world journal 2012: 1-10. bhuiyan, m. k. a., g. j. u. ahmed 2010: performance of mefenacet + bensulfuron methyl 53% wp against weed suppression in transplanted paddy. pak. j. weed sci. res. 16 (2): 181187. brri (bangladesh rice research institute). (2016). adhunik dhaner chash (in bengali). bangladesh rice research institute, joydebpur, gazipur. p.5. fageria, n. k., v. c. baligar.2001.lowland rice response to nitrogen fertilization. communications in soil science and plant analysis 32: 1405-1429. fageria, n. k., v. c. baligar, c. a. jones. 1997. growth and mineral nutrition of field crops. 2nd ed.; marcel dekker, inc.: new york. janiya, j. d., k. moody 1989: weed populations in transplanted and wet-seeded rice as affected by weed control method. tropical pest management 35(1): 8-11 khaliq, a. and a. matloob. 2011. weed-crop competition period in three fine rice cultivars under direct-seeded rice culture. pak. j. weed sci. res. 17(3): 229-243. kim, s. c., k. moody. 1983. minimum sampling size and minimum quadrat number for weed data collection in transplanted rice. j. korean soc. crop sci. 28(3): 319-322. moody, k. 1989. weeds reported in rice in south and south east asia.los banos, philippines.international rice research institute. pp87-102 rao, a. n. 1985. weed vegetation analysis. lecture presented to participants attending the weed science workshop, irri, los baños, philippines. shimul, c. s., m. h. ali, p. k. biswas., r. chakraborty, a. amin and s. khandker.2015. contribution of nitrogen and methods of weeding on the yield components and yield of hybrid boro rice (heera 4). european academic research. vol.ii. issue 12. singh, s., j. k. ladha, r. k. gupta, l. bhushan, a. n. rao. 2008. weed management in aerobic rice systems under varying establishment methods. crop prot. 27: 660-671. srinivasan, e. k., s. natarajan, m. ganapathy and, k. arivazhagan. 2007. effect of nitrogen levels and weed management in hybrid rice. oryza 44(4): 363-365. saleque, m.a., m.j. abedin, n.i. bhuiyan, s.k. zaman and g. m. panaullah. 2004. long-term effects of inorganic and organic fertilizer sources on yield and nutrient accumulation of lowland rice. field crop res. 86: 53–65. tuong, t. p., b. a. m. bouman and m. mortimer, 2005. more rice, less water: integrated approaches for increasing water productivity in irrigated rice-based systems in asia. plant production science 8: 231-241. microsoft word 3. baj-281_revised bangladesh agron. j. 2018, 21(1): 25-37 wheat genotypes as affected by terminal heat stress in northern bangladesh p. bala1* and s. sikder2 1department of agriculture, hazi lalmia city college, gopalganj, bangladesh. 2department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur, bangladesh *corresponding author, e-mail: kbdpronay@yahoo.com (received: 20 june 2017, accepted: 20 april 2018) keywords: cereal crops; yield attributes, high temperature; climate change abstract this study was conducted in crop physiology and ecology research field of hajee mohammad danesh science and technology university, dinajpur during the two successive years of 2011-12 and 2012-13 to identify morpho-physiological attributes of wheat genotypes in response to terminal heat stress. in this respect, three sowing dates at november 27 (normal), december 17 (late) and january 7 (very late growing condition) and eight wheat genotypes viz., pavon-76, prodip, bari gom-25, bari gom-26, baw-1143, baw-1146, baw-1147 and baw-118 were evaluated. growth and morphological changes of wheat genotypes were evaluated in relation to heat tolerance in field condition. growth attributes such as lar, sla and lwr for all the genotypes declined throughout the advancement of growth stages in both the growing seasons and at heat stress condition values of all the parameters such as plant height and grain yields were reduced compared to normal condition. introduction wheat provides 21% of food calories and 20% of protein for more than 4.5 billion people worldwide (barun et al., 2010). it is grown on about 218.5 million hectare in a wide range of environments, with annual production of about 712.31 metric tons (fao, 2014). continual heat stress (mean daily temperature of over 17.5oc in the coolest month of the season) affects approximately 7 million hectares of wheat in developing countries, while terminal heat stress is a problem in 40% of temperate environments, which cover 36 million hectares (reynolds et al., 2010). heat is a non-uniform phenomenon that negatively influences plant growth, morphology, physiology and yield depending upon crop developmental stage, time, and severity of stress (ahmed and prasad, 2011). crops at various growth stages require variable level of temperature for optimum growth. plants have limited nutrient uptake capacity and photosynthetic efficiency under heat stress. this stress can also reduce organ size (leaf, tiller and spikes) and growth period for various development stages at tillering, booting, heading, anthesis and grain filling stages (hossain et al., 2013). plant sensitively to high temperature results in disturbed metabolic process coupled with lower plant biomass accumulation (hasanuzzaman et al., 2013). in bangladesh the optimum time for wheat cultivation lies within november. however, farmers often sow the seeds late even at the end of december due to late harvesting of previous crop, i.e. aman rice (summer rice). consequently, the wheat plant experiences much higher temperature than the optimum at the reproductive phase of growth. high temperature at the terminal growth stage causes lower growth and yield. however, there might have varietal differences in growth and yield performance under high temperature conditions. therefore, this experiment was carried out to select suitable wheat genotypes for growing under late sowing conditions. 26 bala & skder materials and methods the experiment was conducted in the research field of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur, bangladesh from november to april of 2011-12 and 2012-2013. seeds were sown on 27 november (normal), 17 december (late) and 7 january (very late) in main plot and eight genotypes viz. prodip, bari gom-25, bari gom-26, baw-1143, baw-1146, baw-1147, baw-1148 and pavon-76 in sub-plot as experimental materials. the experimental design was a splitplot with three three replications with plot size 2.5 m x 4 m. three irrigations were applied at cri, flowering and grain filling stage. in all sowing dates, at each harvest, the plants were cut off at the ground level and the tops were separated into leaves, stem and panicle (if present) at 10 days interval with start of 20 days after sowing. the harvested plant parts were kept in an electrical oven at about at 70º c for 72 hours and the dry weights of these parts were taken by an electrical balance. leaf area was determined as function of length maximum width × 0.75 (mossad et al. 1995). from the dry weight of different plant parts and leaf area data, the following growth attributes were calculated between two successive harvests according to the classical technique of growth analysis (radford 1967). 1. leaf area ratio )log)(log( ))(log(log )( 1212 1212 lalaww lalaww lar ee ee    2. specific leaf area (sla) dry weight leaf area leaf  3. leaf weight ratio (lwr) dry weightplant total dry weight leaf  where, w2 and w1 are the total dry weights, la2 and la1 are the total leaf area per plant at t2 and t1, the later and the former harvest, respectively. plant height was measured from base of plant to the tip of spike excluding awn with the help of a measuring scale. ten plant samples from each plot were taken and mean was calculated. the data were analyzed by using mstat-c computer package. the treatment means were compared using duncan’s multiple range test (dmrt). results and discussion leaf area ratio (lar) leaf area ratio (lar) was declined steadily with increasing plant age of all the genotypes for each growing condition of both the years. (fig. 1 and fig. 2). lar of all the genotypes started from a higher value at the initial stage of growth and then declined throughout the successive days after sowing in each growing condition in both the years. wheat genotypes as affected by terminal 27 fig. 1. effect of sowing time on leaf area ratio (lar) of eight wheat genotypes at different days after sowing from original values (2011-12). vertical bars indicate se (+) value. 28 bala & skder fig. 2. effect of sowing time on leaf area ratio (lar) of eight wheat genotypes at different days after sowing from original values (2012-13). vertical bars indicate se (+) value. at normal growing condition of both the years, baw-1143 had the highest lar at the initial stage (20-30 das), whereas pavon-76 showed the lowest lar at that growing stage (20-30 wheat genotypes as affected by terminal 29 das). in both late and very late growing conditions, at the initial stage all the genotypes showed higher lar compared to normal growing condition except pavon-76 in both the years. haider (2007) observed that lar was highest during the early vegetative stage but later decreased rapidly with the advancement of plant age, possibly due to abscission of older leaves. similar results were reported by pandy et al. (2000). in fast growing species allocated more carbon to leaves than slow-growing species and that higher lar in fast-growing species allows plants to fix more carbon per unit plant weight. specific leaf area (sla) specific leaf area (sla) of eight wheat genotypes at normal, late and very late growing condition of both the years are shown (fig. 3 and fig. 4). at the early stage of growth, all the genotypes started from higher values of sla and then declined gradually in each growing condition of both the years. in each growing conditions, it was found that genotypes e.g. baw-1143, bari gom -25, bari gom-26 and prodip showed higher sla and genotype pavon-76 always showed the lowest. specific leaf area (sla) of eight wheat genotypes for each of the growing conditions declined throughout the advancement of growth stages in both the years. the normal growing plants had higher sla than those of late growing plants in both the years. haque (2000) found higher sla in some wheat genotypes than the others and timely sown wheat plants showed higher sla than the delayed sowing plants. the decline of sla with age was reported by sarker and paul (1998) in wheat. sla values decreased with increasing plant dry weight. lower value of sla was found in the late and very late sown plants of all the eight genotypes. this result is in agreement with haider (2007) in wheat. leaf weight ratio (lwr) leaf weight ratio (lwr) showed higher values at the early stages of growth and thereafter declined with increasing plant age for all the genotypes in both the growing conditions and years (fig. 5 and 6). under very late growing condition all the genotypes had higher lwr at the early stages of growth and then declined gradually with increasing plant age. under late growing condition, all the genotypes had higher lwr value compared to normal growing condition at all the das with a few exceptions for genotypes baw-1146, baw-1147, baw-1148 and genotype pavon76. at 40 das, the normal growing condition for lwr values of baw-1146, baw-1147, baw-1148 and pavon-76 were higher compared to their respective late growing conditions. under normal growing condition of both the years, baw-1143, bari gom-25, bari gom-26 and prodip showed comparatively lower lwr at all the das compared to other genotypes. 30 bala & skder fig. 3. effect of sowing time on specific leaf area (sla) of eight wheat genotypes at different days after sowing from original values (2011-12). vertical bars indicate se (+) value. 0 50 100 150 200 250 300 350 400 20 30 40 50 60 70 80 90 100 sp ec ifi c le af a re a( c m 2 g-1 ) baw-1146 wheat genotypes as affected by terminal 31 fig. 4. effect of sowing time on specific leaf area (sla) of eight wheat genotypes at different days after sowing from original values (2012-13). vertical bars indicate se + value. saha and paul (1995) studied lwr in wheat and reported that the sharp decrease in lwr at the later stages might be due to the sharp increase of tdm. this result was also supported by haque (2000), sarker and paul (1998), nahar and paul (1998) in wheat. in the present investigation, the late growing plants had higher lwr than those of the normal growing plants in both the years because of lower tdm in the late growing condition throughout the whole growth period. high temperature prevailing at the later stages of late growing condition produced lower tdm. high temperature depressed the mean overall lwr during the later part of the growing period. haider (2007) also stated that with increasing plant age in all the varieties and sowing dates lwr was downward drifts. 32 bala & skder fig. 5. effect of sowing time on leaf weight ratio (lwr) of eight wheat genotypes at different days after sowing from original values (2011-12). vertical bars indicate se (+) value. wheat genotypes as affected by terminal 33 fig. 6. effect of sowing time on leaf weight ratio (lwr) of eight wheat genotypes at different days after sowing from original values (2012-13). vertical bars indicate se (+) value. plant height plant height of eight wheat genotypes at different growing conditions are presented in tables 1 and 2. from the results, it was observed that the combined effect of growing condition and wheat genotypes on plant height was significant in both the years. 34 bala & skder under normal growing condition, baw-1146 attained the highest plant height (103.00 cm and 104.67 cm for first and second year, respectively). the heat sensitive genotype pavon-76 attained the lowest plant height (93.53 cm and 95.00 cm for first and second year respectively). under late and very late growing conditions, plant height was markedly reduced for all the wheat genotypes in different magnitudes. plant height varied under late sowing and very late sowing due to genotype and the combined effect of growing condition. the decrease in plant height may have occurred due to shortening of growth and photosynthetic period imposed by heat stress in a late sown environment. these results coincide with the findings of mishra et al. (2000), and ubaidullah et al. (2006) who observed significant negative effects of delayed planting on plant height in wheat. irfan et al. (2005) also reported reduction in plant height of wheat genotypes due to late sowing and high temperature stress. wheat varieties showed a significant effect of varieties on plant height (mattas et al., 2011 and mohammad et al., 2011) and varied greatly among various wheat genotypes (ford and throne, 2001). the differences in plant height due to various genotypes might be due to varied genetic condition of genotypes table 1. plant height (cm) of eight wheat genotypes under normal, late and very late growing conditions in 2011-12 genotypes plant height(cm) reduction (%) at very late growing condition compared to normal normal growing condition (27 nov.) late growing condition (17 dec.) very late growing condition (7 jan.) prodip 99.00c 93.56d 86.45gh 12.68 bari gom-25 99.58bc 93.66d 86.22gh 13.42 bari gom-26 100.02ac 94.44d 87.00fh 13.02 baw-1143 101.20ac 95.00d 88.00eg 13.04 baw-1146 103.00a 97.00d 90.00e 12.62 baw-1147 102.00ab 96.00d 89.00ef 12.75 baw-1148 102.00ab 96.00d 89.22ef 12.53 pavon-76 93.53d 84.89h 76.32i 18.40 cv (%) 3.21 mean followed by same letter(s) did not differ significantly at 5% level of significance by dmrt table 2. plant height of eight wheat genotypes under normal, late and very late growing conditions in 2012-13 genotypes plant height (cm) reduction (%) at very late growing condition compare to normal normal growing condition (27 nov.) late growing condition (17 dec.) very late growing condition (7 jan.) prodip 100.02c 95.00d 89.65eh 10.37 bari gom-25 100.14c 94.67d 87.25hi 12.87 bari gom-26 100.50c 91.67ef 87.00hj 13.47 baw-1143 101.50bc 91.00eg 89.00fh 12.32 baw-1146 104.67a 95.00d 92.00e 14.02 baw-1147 103.67ab 96.00d 88.67gh 14.47 baw-1148 103.33ab 95.00d 85.33ij 17.40 pavon-76 95.00d 86.33j 81.00k 15.79 cv (%) 4.32 mean followed by same letter(s) did not differ significantly at 5% level of significance by dmrt grain yield at very late growing condition, the grain yield of all the genotypes was reduced more. comparatively genotypes baw-1143, bari gom-26, bari gom-25 and prodip (42.00 to wheat genotypes as affected by terminal 35 50.97 % and 42.71 to 50.59% for the first and second year, respectively) showed lower reduction of grain yield than the mht genotypes and hs genotype pavon-76. regarding relative performance, genotypes baw-1143, bari gom-26, bari gom-25 and prodip also attained higher relative grain yield (49 to 58 % for both the year) than the genotypes pavon-76 (fig. 4). fig. 4: relative grain yield (%) of different wheat genotypes in 2011-12 (upper graph) and 2012-13 (lower graph) compared normal to very late. however, genetic effects are not independent of environmental effects; most genotypes do not perform satisfactorily in all environments. when an interaction between a genotype and the environment occurs, the relative ranking of genotypes for yield often differs when genotypes are compared over a series of environments and/or years (al-otayk, 2010). in bangladesh, early wheat faces high temperature stress at the vegetative stage and late sowing wheat is affected at two stages: germination by low temperature stress (<10oc) and at the reproductive stage by high temperature (>25oc), which ultimately affects grain yield (hossain et al. 2011; 2012). conclusion 36 bala & skder genotypes baw-1143, bari gom-25, bari gom-26 and prodip showed higher sla compared to genotypes baw-1146, baw-1147, and baw-1148. however, genotype pavon-76 always showed the lowest sla at all the das and sowing times compared to the other genotypes. under late and very late growing condition all the genotypes had higher lwr at the early stages of growth and then declined gradually with increasing plant age. in this condition at 40 das, the normal growing condition for lwr values of baw-1146, baw-1147, baw1148 and pavon-76 were higher compared to their respective late growing condition. under normal growing condition of both the years, baw-1143, bari gom-25, bari gom-26 and prodip showed comparatively lower lwr at all the das compared to other genotypes. lar of all the genotypes started from a higher value at the initial stages of growth and then declined throughout the successive days after sowing in each growing condition both the years. in late and very late growing condition, at the initial stage all the genotypes showed higher lar compared to normal growing condition except pavon-76 in both the years. at this initial stage, again baw-1143 attained the highest lar and pavon-76 showed the lowest lar. plant height was found higher late and very late growing condition. genotypes baw-1143, bari gom-25, bari gom-26 and prodip showed higher relative grain yield than that of baw-1146, baw1147 and baw-1148 references ahmad, p. and m. n. v. prasad. 2011. abiotic stress responses in plants metabolism, productivity and sustainability. new york, ny: springer sciences & business media. al-otayk, s. m. 2010. performance of yield and stability of wheat genotypes under high stress environments of the central region of saudi arabia. jkau: met., env. arid land agric. sci. 21 (1), 81-92. barun, h. j., g. atlin and t. payne. 2010. multilocation testing as a tool to identify plant response to global climate change. in: climate change and crop production, reynolds, c. r. p. (ed.), pp. 34-78. cabi, london, u k. fao. 2014. fao statistical year book 2014.world food and agriculture. food and agriculture organization of the united nations, rome italy.pp34-56. ford, m. a. and g. n. 2001. effect of variation in temperature and light intensity at different times on growth and yield of spring wheat. ann. appl.biol., 88: 182-219. haider, s. a. 2007. growth analysis in relation to sowing dates in four varieties of wheat: a functional approach. j. life earth sci. 2 (2): 17-25. haque, m. m. 2000. physiological analysis of yield of wheat (triticum aestivum l.) in relation to sowing date. ph. d. thesis. university of rajshahi, bangladesh. hasanuzzaman, m., k. nahar, m. m. alam, r. roychowdhury and m. fujita. 2013. physiological, biochemical and molecular mechanisms of heat stress tolerance in plants.int.j.mol.sci.14.9643-9684. hossain, a., m. a. z. sarker, m. a. hakim, m. v. lozovskaya and v. p. zvolinsky. 2011. effect of temperature on yield and some agronomic characters of spring wheat (triticum aestivum l.) genotypes. int. j. agril. res. innov. technol.1 (1&2): 44-54. hossain, a. and j. a. teixeira da silva. 2012. phenology, growth and yield of three wheat (triticum aestivum l.) varieties as affected by high temperature stress. not.sci.biol. 4(3): 97-106. hossain, a., m. sarker, m. saifuzzaman, i. teixeita da silva, m. lozovskaya and m. akhter.2013.evaluation of growth, yield, relative performance and heat susceptibility of wheat genotypes as affected by terminal 37 eight wheat (triticum aestivum l.) varietiesas affected by high temperature stress. notular sci.biol.4:97-109. irfan, m., t. muhammad, m. amin and a. jabbar. 2005. performance of yield and other agronomic characters of four wheat genotypes under natural heat stress .int.j. bot. 1(2): 124-127. mattas, k. k., r. s. uppal and r.p. singh. 2011. effect of varieties nd nitrogen management on the growth, yield and noitrogen uptake of durum wheat. res. j. agric. sci. 2: 376-380. mishra, d. k., r. a. khan and m.s. baghel. 2000. stability of wheat varieties under various dates of sowing. ann. agric. res. 21: 564-566. mohammad, f., i. ahmed, n. u. khan, k. maqbool, a. naz, s. shaheen and k. ali. 2011. comparative study of morphological traits in wheat and triticale.pakistan j. bot. 43: 13031310. mossad, m., g. ortiz-ferrara, v. mahalakshmi, and r. a. fischer. 1995. phyllochron response to vernalization and photoperiod in spring wheat. crop sci. 35: 168-171. nahar, n. and n. k. paul. 1998. growth analysis of wheat genotypes under differentsoil moisture regimes. bangladesh j. agril. res. 23: 54-57. pandy, i. b., r. k. pandy, d. k. dwivedi and r.s. singh. 2010. phenology,heat unit requirement and yield of wheat varieties under different crop-growing environment. indian j. agric. sci. 80:136-140. radford, p. j. 1967. growth analysis formulaetheir use and abuse. crop sci. 7: 171-175. reynolds, m. p., d. hays and s. chapman. 2010. breeding for adaptation to heat and drought stress.in: climate change and crop production, c. r. p. reynolds, (eds), pp. 23-65. cabi, and london, uk. saha, s. k. and n. k. paul. 1995. growth of five wheat cultivars as affected by soil moisture. j. bio.sci. 3: 103-112. sarker, a. m and n. k. paul. 1998. studies on growth attributes of wheat under irrigated and rainfed conditions. bangladesh j. bot. 27: 119-126.shewry, p. r. 2009. wheat. j. exp. bot. 60(6): 1537-1553. ubaidullah, r., t. mohammad, h. s. ali and a. w. nassimi. 2006. screening of wheat (triticum aestivum l.) genotypes for some important traits against natural terminal heat stress. pakistan j. boil. sci.9:2069-2075. bangladesh agron. j. 2021, 24(2): 43-54 evaluation of fifteen tomato germplasm for salt tolerance s. nasrin1, m.a. mannan1, m.m. islam1, s.a.k.u. khan1 and s.m.m. rahman2 1agrotechnology discipline and 2biotechnology and genetic engineering discipline, khulna university, khulna, bangladesh corresponding e-mail: shamimakbd.seema@gmail.com (received: 16 august 2021, accepted: 05 september 2021) keywords: germplasm, salinity, salt, tolerance and tomato abstract soil salinity is a serious threat to crop productivity which influence growth and productivity of crop plants. salt tolerance differ species to species and variety to variety. therefore, this research work was initiated to investigate the influence of salinity levels on growth and yield of tomato genotypes and to select suitable variety for salt affected areas. a two factor poly house experiment was conducted in completely randomized design in khulna university, bangladesh, during november 2019 to march 2020. factor one was consisted of fifteen tomato varieties including eight improved varieties developed by bangladesh agricultural research institute (bari) and seven cultivars collected from farmer’s field of khulna region. other factor was consisted of five levels of soil salinity viz. control, 4, 8, 12 and 16 dsm−1. tomato genotypes and salinity usages both significantly dissimilar for the agromorphogenic traits. the plant height, leaf traits and yield traits are negatively influenced by salinity level. the local variety guli gave the highest plant height for all the treatments. tomato var. bari tomato-15 produced the maximum fruit weight plant-1 at control followed by 4dsm-1 and 8 dsm-1. therefore, tomato var. bari tomato-15 may be suitable for cultivation in the areas containing salinity up to 8 dsm-1. this may also help to further improve tomato cultivars in saline areas. introduction tomato (solanum lycopersicum l.) belongs to the genus solanum under the family solanaceae. it is one of the most important vegetable crops in the world in terms of production and area under cultivation. it is a major source of vitamins and minerals such as vitamins a, b, c and calcium (bose and som, 1990). lycopene in tomatoes is a phytochemical antioxidant that reduces the risk of cancer (mutanen et al., 2011). in 2000, fao estimated that 397 million hectares of land were affected by salinity and 434 million hectares by salinity (http://www.fao.org). it is likely that by 2050, more than 50% of agricultural land will be lost to salinization due to poor fresh water irrigation and application of chemicals to the soil (mahajan and tuteja, 2005). bangladesh has 2.86 million hectares of coastal and offshore land. of which about 1.056 million hectares are affected by salinization to varying degrees (srdi, 2010). the higher salinity level than the suggested level (<700 μs/cm) affecting both surface and ground water in south-west coastal region of bangladesh (shammi et al. 2016; islam et. al., 2016). salinity is becoming a major problem in the south-west coastal region of bangladesh, where irrigation water quality is affected by intrusion salinity (islam et al., 2018). soil salinity is the most important abiotic stress that hinders crop development and productivity (ashraf and wahed, 1993; ahmad et al., 2019b). salinity and drought are the main factors that hinder crop growth (boyer, 1982). salinity brings about physiological and metabolic changes that reduce crop yield (pompeiano et al., 2016). salinity affects plant morphology and reduces plant biomass content (parvaiz, 2014). tomato plant growth is moderately sensitive to salinity depending on variety or 44 nasrin et al. growth stage (estan et al., 2005). tomato fruit yield and plant growth were not affected up to 2.6 dsm-1 soil salinity of (hassan et al., 1999). plant height, main branches, flower clusters, fruit clusters, number of fruits, total fruit yield per plant, individual fruit weight, and amino acid content in leaves gradually decreased due to increasing salinity levels (islam et al., 2011). the decrease in tomato yield due to salinity is due to the decrease in fruit number rather than fruit size ((pengfei et al., 2017). in saline areas, cropping intensity is declined (62-114%) compared to the national average (159%) (karim et al. 1990). therefore, this study was carried out to observe the effects of salinity on growth and yield parameters of tomato plants and identify the salinity tolerant variety for better yield under saline conditions among the fifteen variety. materials and methods a two-factor pot experiment was conducted under a poly shade house of khulna university during november 2019 to march 2020. the experiment was laid out in completely randomized design (crd) with three replications. treatments: factor a : fifteen tomato varieties including eight improved varieties developed by bangladesh agricultural research institute (bari), namely bari tomato 2, bari tomato 8, bari tomato14, bari tomato15, bari tomato16, bari tomato17, bari tomato18, bari tomato19 and seven cultivars collected from farmers field of khulna region namely bonkim ruby, pusa ruby. suraksa, patharkuchi, ruma vf, ruma 19 and guli were used as plant material. the seeds of bari tomato varieties were collected from regional agricultural research station (rars), jashore. factor b: one control and four level of salinity was used as experimental treatment in this experiment. the treatments were t0 = control (without nacl), t1= 4dsm-1, t2 = 8 dsm1, t3 = 12 dsm-1 and t4 = 16 dsm-1. the data were statistically analyzed by anova using the mstat-c package program. significance of differences between treatment means was evaluated using duncan's new multiple range test (gomez and gomez, 1984). results and discussion effect of salinity on plant height the significantly highest plant height (103.04 cm) was found in the control, i.e. without salt, which was similar to that recorded in 4 dsm-1 (101.48 cm) and the lowest plant height (86.28 cm) was recorded in 16 dsm-1 (figure 1a). the combined effect of cultivar and salinity level was also found significant in terms of plant height. the maximum plant height (122.3 cm) was recorded from the variety guli with 4 dsm-1 salinity, which was statistically similar to pusha ruby with the control, and bari tomato -19 with the control. the lowest plant height (52.33 cm) was observed in bari tomato-2 with 16 dsm-1 (figure 2). this result is in conformity with javed et al, (2002); moniruzzaman et al., (2013) and al daej, (2018) they observed that the plant height decreased with increasing salinity level. salinity affects plant growth by disturbing the water balance, causing an imbalance in plant nutrition and affecting plant physiological and biochemical processes (yeo et al. 1985; karim et al. 1993). ahmad et al. (2019a) also state different genotypes showed variations against salinity stress. evaluation of fifteen tomato germplasm for salt tolerance 45 fig. 1. growth and yield parameter influenced by different salinity level, a. plant height, b. leaves plant-1, c. leaf length and d. leaf breadth, e. fruits plant-1 and f. fruit weight plant-1 46 nasrin et al. fig. 2. effect different levels of salinity on selected varieties of tomato in respect of plant height, a) bari released variety, b) local variety effect of salinity on number of leaves the maximum number of leaves (38.82) was found in 4 dsm-1 which was statistically similar to the control (38.69) and the lowest number of leaves (34.35) was found in 16 dsm-1 (figure 1b). the combined effect of cultivar and salinity level was also found significant in terms of number of leaves. the maximum number of leaves (46) was recorded from the variety guli with the control that was statistically similar to variety with the 4 dsm-1 and ruma-19, ruma vf and bari tomato -14 with the control and 4dsm-1. the minimum number of leaves (28.56) was found in bari tomato -8 with 16 dsm-1 (figure 3). yadav et al. (2003) and umar et al. (al. (2018) also indicated that the number of leaves plant-1 was reduced under high salinity conditions. in addition, al daej, (2018) and rahman et al, (2018) was found significant differences in the response of different tomato cultivars to salinity. evaluation of fifteen tomato germplasm for salt tolerance 47 fig. 3. effect different levels of salinity on selected varieties of tomato in respect of number of leaves, a) bari released variety, b) local variety effect of salinity on leaf length there were significant variations due to different salinity levels in respect of length of leaves. the maximum leaf (33.1 cm) was found in 4 dsm-1 which was statistically similar to control (32.9) and 8 dsm-1 (32.8 cm) and the shortest leaf (31.0 cm) in 16 dsm-1 (figure 1c). the maximum length of leaves (39.6 cm) was recorded from the variety bari tomato-15 with the control which was statistically similar to bari tomato -15 up to 16 dsm-1. the lowest length of leaves (27.9 cm) was found in patharkuchi with 16 dsm-1 (figure 4). shalhevet (1994) also noted that leaf length decreased under high salinity conditions. length of leaves decrease after 6 dsm-1 salinity and differ significantly among various tomato cultivars (rahman et al. 2018). 48 nasrin et al. fig. 4. effect different levels of salinity on selected varieties of tomato in respect of length of leaf, a) bari released variety, b) local variety effect of salinity on leaf breadth there was a significant variation in leaf breadth due to different salinity levels. the broadest leaf (33.2 cm) was recorded from the control which was followed by 4 dsm-1 (32.6 cm) and the narrowest leaf (29.3 cm) in 16 dsm-1 (figure 1d). significant variation in leaf breadth was also found for the combination of varieties and salinity levels (figure 5). the highest breadth of leaf (38.3 cm) was recorded from the variety bari tomato-16 with the control followed by bari tomato-16 with 4 dsm-1. the lowest breadth of leaves (25.2 cm) was obtained from the variety pusa ruby with 16 dsm-1 salinity level. after 6 dsm-1 the breadth of leaf adversely affect by salinity (rahman et al. 2018). shalhevet, (1994) also stated that, the leaf breadth reduced in high saline condition. evaluation of fifteen tomato germplasm for salt tolerance 49 fig. 5. effect different levels of salinity on selected varieties of tomato in respect of breadth of leaf, a) bari released variety, b) local variety effect of salinity on the number of fruits plant-1 different salinity levels had a significant effect on the number of fruits plant-1 (figure 1e). the maximum number of fruits plant-1(14.4) were observed in 4 dsm-1 which was statistical similar to the control (14.4) followed by the 8dsm-1 (12.9). the minimum number of fruits plant-1was found in 16 dsm-1 (9.5). the combined effect of variety and salinity level was also found significant in the case of number of fruits per plant (figure 6). the maximum number of fruits plant-1 (22.6) was found in ruma19 with control which was statistically similar to bari tomato-16 with control (20.6) and that was the minimum (4.3) in bari tomato-17 with 12 dsm-1and 16 dsm-1. ahmad et al. (2019) also stated that number of fruits plant-1decrease with increasing salinity level. similar results were found by islam et al, 50 nasrin et al. (2011) and umar et al, (2018) who reported that fruit number of tomato decreased with increasing salinity and different genotypes of tomato showed different fruit numbers in respect to salinity. fig. 6. effect different levels of salinity on selected varieties of tomato in respect of number of fruits per plant, a) bari released variety, b) local variety effects of salinity level on weight of fruits per plant significant variations were found in different salinity levels in respect of weight of fruits per plant (figure 1f). the maximum weight of fruits plant-1 (422.5 g) was observed in 4 dsm-1 which was statistical similar to the control (415.8 g) followed by the 8dsm-1 (369.0 g). the minimum weight of fruit plant-1was found in 16 dsm-1(262.46 g). the combined effect of variety and salinity levels was also found significant in weight of fruits plant-1 (figure 7). the maximum weight of fruits plant-1 (708.0 g) was found in bari tomato-15 with 4 dsm-1 that was statistically similar to bari tomato15 with 8 dsm-1 (681.0 g) and control (656.3 g) and the minimum (132.6) in ruma-19 with 16 dsm-1 salinity levels. reduction of yield of tomato by salinity is due to the reduction of number of fruit rather than fruit size (pengfei et al., 2017). the number of fruits per plant and fruit weight decreased with increasing salinity (cho et al., 1996; moniruzzaman et al., 2013 and rahman et al., 2018). in later stages, salinity reduces yield by affecting growth parameters (karim et al. 1993). in pot soil, the ph, organic matter (om), na, k, ca, and p increase with salinity but the total nitrogen (n) decrease and evaluation of fifteen tomato germplasm for salt tolerance 51 finally halves the fruit production (rahman et al. 2018). the addition of salt solution to the pot soil might have deleterious effects on the physico-chemical properties of the soil (fontes and ronchi 2002). fig. 7. effect different levels of salinity on selected varieties of tomato in respect of weight of fruits plant-1, a) bari released variety, b) local variety average performance of the variety the varieties used in the trial showed significant differences in growth and yield characteristics. guli was the tallest variety and bari tomato-2 was the shortest one. the variety with the highest number of leaves was found in guli while lowest number of leaves in bari tomato-8. in terms of leaf length, bari tomato-15 had the longest leaves and ruma vf produced the shortest one. the narrowest leaves were found in ruma vf and the widest leaves recorded from bari tomato 15. bari tomato 15 had the highest number of fruits and bari tomato 17 had the least number of fruits which was one third of bari tomato 15. the highest fruit yield was recorded in bari tomato 15 and the lowest in guli (figure 8). 52 nasrin et al. v1. bari tomato 2, v2. bari tomato 8, v3. bari tomato14, v4. bari tomato 15, v5. bari tomato16, v6. bari tomato17, v7. bari tomato18, v8. bari tomato 19, v9. bonkim ruby, v10.pusa ruby, v11. suraksa, v12. patharkuchi, v13. ruma vf, v14. ruma 19, v15. guli fig. 8. average performance of tomato varieties in respect of growth and yield traits, a). plant height, b) leaves plant-1, c). leaf length and d). leaf breadth, e). fruits plant-1 and f). fruit weight plant-1 conclusion the results showed that both tomato genotypes and salinity treatments were significantly different from the agro-morphological traits of tomato plants. higher salinity levels were not suitable for plant height, number of leaf, length of leaf, breath of leaf, fruits plant-1 and weight of fruits plant-1. local tomato variety guli gave the better plant height up to 12 4dsm-1. tomato var. bari tomato 15 gave highest fruit weight per plant up to 8 dsm-1. this could be a very good opening point for advance research on salinity-tolerant varieties. evaluation of fifteen tomato germplasm for salt tolerance 53 acknowledgements the authors are grateful to the bangobondhu fellowship trust for financial support to conduct the study. references ahmad, m., a. shoukat, m. anjum, m. kamran, m. q.saeed, r. hussain, m. h. abbas and y. shafiq. 2019a. assessment of tomato genotypes against salinity on the basis of morphological and physiological parameters in hydroponic conditions. nat. sci., 17 (2): 56-70. http://www.sciencepub.net/nature, doi:10.7537/marsnsj170219.06. ahmad, r., s. hussain, m.a. anjum, m.f. khalid, m. saqib, i. zakir, a. hassan, s. fahad, s. ahmad, 2019b. oxidative stress and antioxidant defense mechanisms in plants, under salt stress in plant abiotic stress tolerance. springer: 191–205. al-daej, m.i. 2018. salt tolerance of some tomato (solanum lycopersicum l.) cultivars for salinity under controlled conditions. ame. j. pl. phy. 13: 58-64. ashraf, m. and a. wahed. 1993. response of some genetically divers lines of chickpea to salt. aust. j. pl. phys., 154: 257-266. https://www.jstor.org/stable/42939026. bose, t.k. and. m.g. som. 1990. vegetable crops in india. published by b. mitra and naya prokash, 206, bidlran sarani, calcutta, india, pp.241-249. boyer, j.s. 1982. genetic plant productivity and the environment. science, 218: 443-448. cho j.y., s.j. chung and a. feigin. 1996. interactive effects of saline on photosynthesis and related growth parameters in tomatoes. pp.549-554. estan, m.t., m.m. martinez-rodriguez, f. perez-alfocea, t.j. flowers, m.c. bolarin. 2005. grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shoot. j. exp. bot. 56: 703–712. fontes, p.c.r. and c.p. ronchi. 2002. critical values of nitrogen indices in tomato plants grown in soil and nutrient solution determined by different statistical procedures. pesq. agropec. bras. 37: 14211429 gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. (2nd edn.). john wiley and sons, new york, usa, pp: 1-340. hassan, m.m., t.a. el-masry, and a.a. abou-arab. 1999. effect of soil salinity on growth, yield and elemental concentrations in tomato. egt j. hort. 26(2): 187 198. http://www.fao.org/soils-portal/soil-management/management-of-some-problem-soils/salt-affectedsoils/more-information-on-salt-affected-soils/en/. islam m.a., m.m. rahman, m. bodrud-doza, m.i. muhib, m. shammi and a. zahid. 2018. a study of groundwater irrigation water quality in south-central bangladesh: a geo-statistical model approach using gis and multivariate statistics, acta geochim, 37: 193–214. islam m. a., a. zahid, m.m. rahman, m.s. rahman, m.j. islam, y. akter. 2016. investigation of groundwater quality and its suitability for drinking and agricultural use in the south central part of the coastal region in bangladesh, expo. health, 9: 27-41. islam, m.t., m.i. aral, m.a. hossain, a.k. sen and r.k. dutta. 2011. identification of tomato genotypes for salt tolarence, in. j. sust. crop prod. 6(1): 17-21. javed, a., u.h. tanveer and s. muhammad. 2002. effect of salinity on yield, growth and nutrient contentment of tomato, pak. j. agric. sci. 39(2): 76-79. karim m.a., e. nawata, and s. sigenaga. 1993. effects of salinity and water stress on the growth, yield and physiological characteristics in hexaploid triticale, jpn. j. trop. agric., 37: 46-52 karim z., s.g. hussain and m. ahmed. 1990. salinity problems and crop intensification in the coastal regions of bangladesh, barc, dhaka. http://www.fao.org/soils-portal/soil-management/management-of-some-problem-soils/salt-affected-soils/more-information-on-salt-affected-soils/en/ http://www.fao.org/soils-portal/soil-management/management-of-some-problem-soils/salt-affected-soils/more-information-on-salt-affected-soils/en/ 54 nasrin et al. mahajan, s. and n. tuteja. 2005. cold, salinity and drought stresses: an overview. arch. biochem. biophysics, 444(2): 139–158. doi: 10.1016/j.abb.2005.10.018. moniruzzaman, m., m.n. islam, m.f.b. hossain, m.m. rashid and k.u. ahamed. 2013. evaluation of tomato germplasm against salinity. bul. ins. trop. agric., kyushu univ. 36: 9-16. parvaiz, m. 2014. response of maize to salt stress a critical review. int. j. healt. sci. (ijhs), 1(1): 13-25. pengfei, z., m. masateru and d. yanyan. 2017. effects of salinity stress at different growth stages on tomato growth, yield and water use efficiency. communications in soil science and plant analysis. the united graduate school of agricultural sciences, gifu university, 1-1 yanagido, japan. pp.5011193. doi.org/10.1080/00103624.2016.1269803. pompeiano, a., e. di patrizio, m. volterrani, a. scartazza, l. guglielminetti. 2016. growth responses and physiological traits of seashore paspalum subjected to short-term salinity stress and recovery. agr. water manag. 163: 57–65. doi: 10.1016/j.agwat.2015.09.004. rahman, m.m., m. hossain, k.f.b. hossain, m.t. sikder, m. shammi, m. rasheduzzaman, m.a. hossain, a.m. alam and m.k. uddin. 2018. effects of nacl-salinity on tomato (lycopersicon esculentum mill.) plants in a pot experiment. open agric. 3: 578–585. shalhevet, j. 1994. using water of marginal quality for crop production. major issues, agric. wat. mang. 25(3): 233-269. doi.org/10.1016/0378-3774 (94)90063-9. shammi m., b. karmaker, m.m. rahman, m.s. islam, r. rahman and m.k. uddin. 2016. assessment of salinity hazard of irrigation water quality in monsoon season of batiaghata upazila, khulna district, bangladesh and adaptation strategies, pollution, 2: 183-197. srdi. 2010. srmaf project. soil resource development institute. ministry of agriculture. government of the people’s republic of bangladesh. pp. 1–60. umar, j., a. aliyu, k. shehu and l. abubakar. 2018. a study on effects of salinity on growth and yield of tomato genotype (solanum lycopersicum), sust. food prod. 3:16-24. doi: 10.18052/www.scipress.com/sfp.3.16. yadav, r., k.r. chaturvedi, dubey, sarwan, p.k. joshi and p. minhas. 2003. potentials and hazards associated with sewage irrigation in haryana, in. j. agric. sci. 73: 249-255. yeo, a.r., s.j.m. capcorn and t.j. flowers. 1985. the effect of salinity upon photosynthesis in rice (oryza sativa l.): gas exchange by individual leaves in relation to their salt content, j. exp. bot. 36: 12401248. effect of salinity on the number of fruits plant-1 different salinity levels had a significant effect on the number of fruits plant-1 (figure 1e). the maximum number of fruits plant-1(14.4) were observed in 4 dsm-1 which was statistical similar to the control (14.4) followed by the 8dsm-1 (12.9). the ... effects of salinity level on weight of fruits per plant significant variations were found in different salinity levels in respect of weight of fruits per plant (figure 1f). the maximum weight of fruits plant-1 (422.5 g) was observed in 4 dsm-1 which was statistical similar to the control (415.8 g) followed... bangladesh agron. j. 2022, 25(1): 83-90 improvement of existing cropping pattern through short duration mustard variety in the chalanbeel area s.s. kakon, m.a.k. mian1, a.a. begum, j.a. chowdhury, r.r. saha2 and d.a. choudhury agronomy division, 1cso, research wing, 2former director,planning and evaluation wing, bangladesh agricultural research institute, gazipur, bangladesh corresponding e-mail: kakonbari@gmail.com (received: 15 may 2022, accepted: 21 june 2022) keywords: mustard, yield, rice equivalent yield and chalanbeel abstract the experiment was conducted at dobila, tarash of shirajgonj in chalanbeel during the rabi seasons of 2018-2019 and 2019-2020 to improve the existing cropping pattern, increase cropping intensity, yields and economic return through incorporating of modern crop varieties and improved management practices. the treatments were i) mustard (var. barisarisha-14)-boro-fallow cropping pattern, ii) mustard (var. bari sarisha-15)boro-fallow cropping pattern, iii) mustard (var. tori-7)-boro-fallow cropping patternandiv) fallow–boro–fallow (existing cropping pattern). boro rice (var. brri dhan29) was used to improve cropping pattern. the results revealed that the mean crop duration of improved cropping pattern ranged 192-195 days by inclusion of mustard. rice equivalent yield of improved cropping pattern was 9.51-10.04 t ha-1 year-1 which was 46% higher than that of existing pattern (5.37 t ha-1 year-1). land use efficiency (53%) of improved cropping pattern were 9 and 47% higher, respectively than those of existing cropping pattern. higher mean gross return (tk. 2,80,860 ha-1), gross margin (tk. 169680 ha-1) and bcr (2.53) were recorded in improved cropping pattern: mustard (var. bari sarisha-14)boro – fallow} due to inclusion of high yielding variety of mustard than existing cropping pattern (gross return: tk. 161010 ha-1 and gross margin: tk. 86183 ha1) in chalanbeel area. therefore, farmers in chalanbeel region of bangladesh could follow improved cropping pattern for higher crop productivity and profitability where lands remain fallow before transplanting of boro rice. introduction bangladesh is predominately an agricultural country. it is one of the most densely populated countries of the world with population growth rate of 1.34% (bbs, 2017). rice occupies about 74% of the total cropped area and is cultivated in three seasons in a year (bbs, 2017). in rice based cropping pattern, t. aman-fallow-boro-fallow is dominant where cropping intensity is 200% (aziz et al., 2011). at present total cultivable land is 8.5 million hectare and it is shrinking day by day. the annual loss of agricultural land is about 0.73% per annum due to construction of houses, roads and industrial infrastructure (bbs, 2019). a number of reports on different cropping pattern are available in bangladesh and india that an additional crop could be introduced without much changes or replacing the existing ones for considerable increases of productivity as well as profitability of the farmers (khan et al., 2005; nazrul et al., 2013, kamrozzaman et al., 2015). the cropping pattern in an area depends largely on agroclimatic, technical and institutional factors (vaidyanathan, 1987). there is very little scope of increasing cultivable land but there are scopes of increasing cropping intensity from the present level of 84 kakon et al. 190% to 250% by improving the present cropping pattern incorporating short duration crops like: lentil, mustard, potato etc. in the existing cropping pattern in different unfavourable ecosystem. beel (low land goes under water and remains under water about 4-5 months generally from july to november) areas are under unfavourable ecosystem covering an area of 2.43 million hectares in bangladesh (aziz et al., 2016). chalanbeel is an extensive lowland area in the lower atrai basin and spreads across singra and gurudaspur upazilas of natore district, chatmohar, bhangura, faridpur upazilas of pabna district and ullahpara, rajgonj and tarash upazilas of sirajgonj district. generally unfavourable ecosystem is less productive and remains fallow in most of the part of the year. the existing major cropping pattern under chalanbeel area is: fallow–boro-fallow and hence the land remains fallow in the rabi and kharif season in this area. the cropping intensity of this region is therefore remarkably low compared to other regions of this country. among the rice crop, boro rice receives the most irrigation water of all crops, with an estimated amount of 1,000 mm/cycle. for production one kg rice grain 3000-5000 l water is required (rahman et al., 2013 and hossain et al., 2014). on the contrary, mustard, lentil, wheat, potato, mungbean, maize, vegetables like cabbage, cauliflower, yard long bean, spinach and aus rice receive less irrigation water for successfully cultivation than boro rice. but the crop productivity could be increased by improving existing cropping patterns through by introducing new crops and crop varieties suitable for the region. high yielding short duration variety along with modern cultivation techniques are the prerequisite for developing improved cropping pattern. only rice production is not profitable and suitable for the farmers of this area due to it requires huge amount of irrigation water for boro cultivation as well as soil native fertility decline for monoculture of rice (sarker et al., 2020). a huge part of land remains fallow 4 to 5 months after harvest of boro rice in this area. mustard can easily be cultivated in this region after harvest of boro rice and can get high economic return within a short time. recently, bangladesh agricultural research institute (bari) has developed high yielding mustard (brassica campestris) varieties, bari sarisha-14 and bari sarisha-15 whose yield potential is higher than tori-7 and can easily be cultivated before boro rice. in chalanbeel area, duration of flood, flooding depth etc. are the most important factor that influence of cropping pattern. at present situation, some farmers of chalanbeel area are interested to cultivate maize, wheat, garlic and oilseeds crops (like mustard) after receding of water from the soil. in most cases, farmers cultivate tori-7. but the farmers harvest poor yield from local var. tori-7 that can be increased by introducing high yielding varieties (alam and rahman, 2006; basak et al., 2007). crop duration of bari developed short duration mustard varieties is 75-85 days, whereas brri and bina has developed short/medium duration rice varieties. under this situation, the experiment was undertakento introduce mustard in fallow-boro-fallow cropping pattern and productivity through rice based cropping pattern. materials and methods the experiment was conducted at dobila, tarash of shirajgonj in chalanbeel during the rabi season of 2018-2020. the treatments were i) mustard (bari sarisha-14)boro rice, ii) mustard (var. bari sarisha-15)-boro rice, iii) mustard (var. tori-7)-boro rice iv) fallow-borofallow. the experiment was laid out in rcb design with four dispersed replications (farmers’ field). unit plot size was 20 decimals. the experimental site belongs to aez-5 of sirajgonj. the land type is medium low land (generally water depth 1.4-2.3 m) waterlogged 4-5 months from july to october. the geographical position of the area is between 24.52○n latitude and 89.01○e longitude. the land was low land and the soil of the study area was silt loam in texture. the meteorological data of the experimental site revealed that the highest temperature prevails in august-september and the lowest in december to january. in both years, there was no precipitation in december. maximum rainfall was received during the months of july. the soil was silty clay loam in texture having ph 7.24. soil samples were collected from the experimental field from a depth of 0-15cm prior to application of fertilizer. results of soil analysis of chemical properties are presented in table 1. organic matter concentration in soil was low (1.34%) and improvement of existing cropping pattern through mustard 85 deficient in total n (0.088%), available p (33.05 ppm), exchangeable k (0.274meq 100-1 g soil), available s (17.08 ppm) and available b (0.235 ppm). all agronomic activities including sowing/transplanting and harvesting date, seed rate, plant spacing, fertilizer management etc. were mentioned in table 2. mustard was the first crop of the sequence. the seeds were sown on broadcast with seed rate of 08 kg /ha on 5-12 november, 2018 and 2019, in two consecutive years. fertilizer management was done followed by frg (2012) and intercultural operations like weeding, mulching, irrigation and pest management were done to support the normal growth of the crops. the crop was harvested on 24 january5 february, 2019 and 2020 in 1st and 2nd year, respectively. after harvest of mustard then boro rice was the second crop of the sequence. boro rice seedlings were grown in adjacent plot and 35-40 days old seedlings were transplanted with a spacing of 20 cm  15 cm. boro rice seedlings were transplanted on 02-05 february, 2019 and 2020 and harvested on 05-20 may, 2019 and 2020 in 1st and 2nd year, respectively. fertilizer management and other intercultural operations like weeding, mulching, irrigation and pest management were done according to brri (2013). rice plant was harvested at 30 cm height from soil surface and remaining parts of the plants were incorporated in soil. for comparison among the crop sequences, the yields of all crops were converted into rice equivalent yield on the basis of prevailing market price of individual crops (verma and modgal, 1983). the economic indices like gross return, gross margin and benefit cost ratio were also calculated on the basis of prevailing market price of the inputs and outputs (produces). land use efficiency land use efficiency was calculated by taking total duration of individual crop in a sequence divided by 365 days (tomer and tiwari, 1990). it was calculated by following formula. land use efficiency = d1+ d2+d3+d4 365 × 100 where d1 + d2 + d3 and d4, the duration of first, second, third and fourth crop of the pattern. production efficiency production efficiency values in terms of kgha-1day-1were calculated by total production in a cropping sequence divided by total duration of crops in that sequence (tomer and tiwari, 1990). y1 + y2 + y3 + y4 d1 + d2 + d3 + d4 y1: yield of 1st crop y2: yield of 2nd crop y3: yield of 3rd crop y4: yield of 4th crop d1= duration of 1st crop of the pattern d2= duration of 2nd crop of the pattern d3= duration of 3rd crop of the pattern d4= duration of 4th crop of the pattern crop cut was done from an area of one square meter at three spots from each plot for yield samples in all cases. the data on yield and economics of all the crops were taken plot wise and stated in table 2. table 1. chemical properties of experimental soil (initial) location aez ph om (%) total n (%) available p (µg/ml) exchange able k (meg/100g) available s (µg/g) available b (µg/g) chalanbeel area, sirajgonj 05 7.24 1.34 0.088 33.05 0.274 17.08 0.235 86 kakon et al. table 2. crop management of existing and improve cropping patterns in the chalanbeel areas of sirajganj during the year of 2018-2020 parameter fallowborofallow mustard-boro-fallow mustard –boro-fallow mustard –boro-fallow crop rice mustard rice mustard rice mustard rice varieties brri dhan29 bari sarisha-14 brri dhan29 bari sarisha-15 brri dhan29 tori-7 brri dhan29 date of sowing/ transplanting 07.2.19 09.11.18 09.2.19 12.11.18 14.02.19 6.11.18 29.01.19 11.2.20 05.11.19 05.2.20 10.11.19 11.02.20 9.11.19 02.02.20 seed rate (g/kg ha-1) 50 8 50 8 50 7 50 sowing method line broadcast line broadcast line broadcast line spacing (cm) 25×15 25×15 20×15 20×15 seedling age (days) 35-40 35-40 35-40 40-45 fertilizer dose (kg ha-1) (n, p, k, s, zn and b) 136-2520-8-0-0 105-32-4024-2-1 140-20-6518-2.6-0 105-32-4024-2-1 140-20-6518-2.6-0 115-34-4436-1-1 140-20-6518-2.6-0 irrigation (no.) several times 1 several times 1 several times 1 several times weeding (no.) 1 weeding at 20-25 dat 1 2 weeding 1st once at 15-20 dat and 2nd at 40 dat 1 2 weeding 1st once at 15-20 dat and 2nd at 40 dat 1 weeding at 20-25 dat date of harvesting (range) 20.5.19 4.02.19 24.05.19 5.02.20 2.06.20 24.01.19 05.05.19 25.5.20 1.02.20 22.05.20 8.02.19 29.05.19 26.01.20 08.05.20 field duration (days) 102 87 105 89 106 80 97 103 88 108 90 109 76 95 turnaround time (days) 5 9 5 4 3 3 results and discussion yield and yield components of different mustard varieties differed significantly but had no significant variation in plantsm-2 (table 3). among the variety, variation was found in case of days to maturity and it was 84, 86, and 74 days for bari sarisha-14, bari sarisha-15 and tori-7. the tallest plant (95.00 cm) was recorded in bari sarisha-15 and the shortest plant in tori-7. number of siliquae plant-1 varied significantly in different mustard varieties. the maximum number of siliquae plant-1 was recorded in bari sarisha-14 (90) which was followed by bari sarisha-15 (81). tori-7 produced the lowest number of siliquae plant-1 (45). the highest number of siliquae plant-1 of bari sarisha-14 and bari sarisha-15 seemed to be related to the tall statured and more branched canopy. similar trend was observed in seeds siliqua-1. the maximum 1000-seedweight was found in bari sarisha-14 (3.57 g) which was followed by bari sarisha-15 (3.42 g). improvement of existing cropping pattern through mustard 87 seed yield also differed significantly among mustard varieties. mustard var. bari sarisha-14 produced the highest seed yield (1787 kgha-1) which was 51% higher than tori-7. the highest seed yield of bari sarisha-14 might be due to cumulative effect of siliquae plant-1 and 1000-seeds weight. bari sarisha-15 was second yielder (1619 kg ha-1). the yield level of bari sarisha-15 was also higher (45%) than that of tori -7. table 3. performance of short duration mustard varieties in chalanbeel area during rabi season of 2018-19 and 2019-20 (pooled analysis) variety days to maturity plants m-2 (no.) plant height (cm) siliquae plant-1 (no.) seeds siliqua-1 (no.) 1000seed wt.(g) seed yield (kg ha-1) stover (kg ha-1) bari sarisha-14 84 54 85 90 25 3.57 1787 2482.50 bari sarisha-15 86 59 95 81 20 3.42 1619 2137.50 tori -7 74 62 72 45 14 2.73 876 1260.00 level of significance 4.62 ns 5.87 7.09 13.73 0.095 70.49 169.6 cv (%) 3.29 12.66 4.04 5.71 4.7 3.60 6.36 5.00 seed yield mustard–boro-fallow cropping pattern gave higher grain yield of boro than fallow–borofallow cropping pattern (table 4). the rice equivalent yield revealed that mustard–boro-fallow cropping pattern produced higher rice equivalent yield (10.04 and 9.51 t ha-1) over farmer’s existing cropping system (5.37 t ha-1). higher rice equivalent yield was obtained in improved cropping pattern due to inclusion of short duration mustard and high yielding varieties as well as improved management technologies. the rice equivalent yield was higher in mustard (var. bari sarisha-14)–boro-fallow cropping pattern which was gave 46% higher than the sole rice yield (5.37 t ha-1) whereas mustard (var. bari sarisha-15)–boro-fallow pattern was showed 28% increased yield than the sole rice cultivation. the lower rice equivalent yield (5.37 t ha-1and 7.62 t ha-1) was obtained in the farmer’s pattern with local variety (tori -7) in mustard and traditional management practices. it is evident from the above findings that improved cropping pattern gave higher yield compared to existing pattern. this finding was in agreement with that of by nazrul et al. (2017), rahman et al. (2015) and nazrul et al. (2013). field duration: in improved pattern mustard var. bari sarisha-14 and bari sarisha-15 and rice var. brri dhan-29 was used in boro. bari sarisha-14 needed 7-12 more days to attained maturity than tori-7. as a result, production efficiency and land use efficiency was higher in improved pattern than farmer’s existing cropping pattern. though turn around time in improved pattern very crucial so all inputs including land preparation should be done in proper time (table 2). cost and return analysis from the economic point of view, mustard-boro–fallow cropping pattern showed its superiority over fallow–boro-fallow/mustard–borofallow cropping pattern. the highest gross margin of the mustard (bari sarisha-14)–boro-fallow pattern was tk. 169680 ha-1, which was 42% higher than that of sole boro cultivation (table 4). similarly, the gross return of the mustard–boro-fallow cropping pattern was tk. 280860 ha-1, which was 42% higher than sole boro rice. the production cost per hectare in mustrad–boro-fallow pattern (tk. 111180 ha-1) was 33% higher over that of sole rice production cost. the higher gross margin of mustard–boro-fallow was achieved mainly due to higher yield advantages of component crops. higher (2.53) bcr was recorded in mustrad–boro-fallow pattern over that of sole rice production and mustard (tori-7)-boro-fallow pattern, respectively (table 4). land use efficiency: land use efficiency is the effective use of land in a cropping year, which mostly depends on crop duration. the land-use efficiency of mustrad–boro-fallow pattern was 47% higher (53%) than that of existing pattern (28%) (table 4). the land use efficiency was higher in mustrad– boro-fallow due to cultivation of mustard in the pattern.the similar trend of the findings was cited by nazrul et al. (2017), rahman et al. (2015) and nazrul et al. (2013). 88 kakon et al. production efficiency: the production efficiency of mustrad–borofallow pattern was found to be 74.98kg ha-1 cropping pattern while in existing cropping pattern it was found to be 52.0 and 67.90 kg ha-1 day-1 for fallow–boro-fallow pattern and mustard (tori-7)-boro-fallow pattern, respectively (table 4). pest and disease incidence: no disease or pest incidence was observed in the experiment plots. farmers’ opinion farmers are interested to grow bari released variety of mustard in this area. they opined that the mustard (bari sarisha-14) cultivation before rice gave the higher economic return against the fallow– boro-fallow pattern. training on production technology for mustard–boro-fallow pattern is needed. table 4. yield and economic performance of existing and improved cropping patterns in the chalanbeel areas of sirajganj during the year of 2018-19 and 2019-20 (pooled analysis) parameter fallowborofallow mustard-boro-fallow mustard-boro-fallow mustard-boro-fallow crop rice mustard rice mustard rice mustard rice varieties brri dhan29 bari sarisha-14 brri dhan29 bari sarisha-15 brri dhan29 tori-7 brri dhan29 yield (t ha-1) 5.37 1.79 5.72 1.62 5.65 0.87 5.53 straw yield (t ha-1) 6.69 2.5 6.84 2.14 6.8 1.26 6.58 rice equivalent yield (t ha-1 year-1) 5.37 10.04 9.51 7.61 bcr 2.15 2.53 2.36 2.21 gross return (tk. ha-1) 161010 110500 170360 98740 168450 53460 164570 280860 267190 218030 total cost (tk. ha-1) 74827 40960 70220 39960 73200 33605 65245 gross margin (tk. ha-1) 86183 169680 154030 119180 lue (%) 28 53 53 48 pe (kgha-1day-1) 52 74.98 71.50 67.90 unit price (tk. kg-1): boro rice=25, rice straw= 4, mustard=60, mustard straw = 1 conclusion the total crop productivity (in terms of rey), land use efficiency and profitability of improved cropping pattern i.e., mustard (var: bari sarisha-14)boro rice (var: brri dhan29)fallow were much higher than that of existing cropping pattern fallow–(var: brri dhan29)-fallow due to inclusion of hyv short duration mustard. thus, mustard var. bari sarisha-14 can be successfully accommodated in the existing cropping pattern which increased cropping intensity and system productivity with reasonable profitability. references alam, m.m. and m.m. rahman. 2006. effect of row spacing on seed yield of five varieties of rapeseed, bangladesh j. crop sci. 17(1): 163-168. aziz, m.a. and a.k.m.h. rahman. 2011. development of alternate cropping pattern for coastal saline of bangladesh against farmer existing t. aman – fallow fallow pattern. annual research report, 2010-11. agronomy division. bangladesh agricultural research institute. gazipur. pp.259-260. aziz, m.a., m.s. alom, j.a chowdhury, a.a begum, s.s. kakon, m.z ali, s. akther, s.k. paul, m.a.m. mia and m.s.a khan. 2016. survey on crops and cropping at chalanbeel areas of bangladesh. bari annual report, agronomy division. 171p. improvement of existing cropping pattern through mustard 89 basak, n.c., j.c. pandit and m.h. khurram. 2007. on-farm evaluation of three mustard varieties under different fertilizer packages. bangladesh j. sci. ind. res. 42(3): 335-340. bbs (bangladesh bureau of statistics). 2017. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning. dhaka. bangladesh. bbs (bangladesh bureau of statistics). 2019. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning. dhaka. bangladesh. brri (bangladesh rice research institute). 2013. modern rice cultivation, 17th edition. bangladesh rice research institute (brri), gazipur 1701. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council (barc), farmgate, new airport road, dhaka-1215. p.274. hossain, m.a., m.o. ali, m.g. hossain, f. khatun, a.h.m.m. haque, r.h. mondol and m.b. anowar. 2014. fashal dharay dal fashal paribeshbandhob o takshi krishi projukti. pulses res. sub-station, bangladesh agri. res. inst. gazipur. kamrozzaman, m.m., m.a.h. khan, s. ahmed and a.f.m.r. quddus. 2015. on-farm evaluation of production potential and economics of wheat – jute-t. aman rice-based cropping system. j. bangladesh agril. univ. 13(1): 93–100. khan, m.a.h., m.a. quayyum, m.i. nazrul, n. sultana and m.r.a. mollah. 2005. on-farm evaluation of production potential and economics of mustard-rice based improved cropping system. j. socio. res. dev. 2(1): 37-42. nazrul, m.i., m. k. hasan and m. r. i. mondal. 2017. production potential and economics of mungbean in rice based cropping pattern in sylhet region under aez 20. bangladesh j. agril. res. 42(3): 413 424. nazrul, m.i., m.r. shaheb, m.a.h. khan and a.s.m.m.r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh j. agril. res. 16(2): 41-50. rahman, m.m., m.a.r. sarkar, m.m. masood, m.j. uddin and m.j. ali. 2013. dry direct seeded boro rice production technology. dept. of agron. bau. mymensingh. rahman, m.m., m.a. rahaman, m. ahmed, m.m. uddin and a.k. choudhury. 2015. improvement from `mustard-boro-t.aman cropping pattern to mustard–boro-jute-t.aman. bangladesh j. agril. res. 40(2): 259-270. sarker, u.k., s. monira and m.r. uddin. 2020. on-farm evaluation and system productivity of wheat-jutet. aman rice cropping pattern in char area of bangladesh. agril. sci. 2(1): 39-46. tomer, s.s and a.s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35(1& 2): 30-35. vaidyanathan, a. 1987. agricultural development in eastern india. economic and political weekly, 22(52), december 26, 1987. verma, s.p and s.c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2): 89-92. bangladesh agron. j. 2018, 21(2): 33-44 performance of legumes on weed suppression with hybrid maize intercropping q. naher, s. m. r. karim1 and m.begum1 onfarm research division, bangladesh agricultural research institute (bari), gazipur 1bangladesh agricultural university, mymensingh corresponding author, e-mail: kakonbari@gmail.com (received: 22 november 2018, accepted: 9 april 2019) key words: maize, legume crop, intercropping, weed suppression, yield abstract field experiment was carried out at the bangladesh agricultural research institute, joydebpur, gazipur during 2010 to 2011 to identify suitable legume crops with maize in maize + legume intercropping systems for better weed suppression, productivity and economic benefits in rabi season. there were 17 treatments of which two sole crop of hybrid maize (zea mays bari hybrid bhutta -9) (weed free and no weeding), three weed free sole crops of pea (sn), bushbean (sn) and cowpea (sn) in rabi season, and their intercropping. twelve intercropping with different weeding regimes (no weeding, one hand weeding at 20 days after emergence (dae), one hand weeding at 40 dae, and two hand weeding at 20 and 40 dae of maize-legume intercropping under normal row (75 cm  25 cm), and two rows of legumes in between two rows of maize were used . among all intercropping, maize-pea with two hand weeding at 20 and 40 dae gave the lowest (6.57 g m-2 at harvest) weed dry weight and the highest weed control efficiency (86% at harvest). maize-pea with two hand weeding at 20 and 40 dae gave the highest yield (maize: 7.58 t ha-1; 6.27 t ha-1 pea), resource complementarily and profitability (ler = 1.89, bcr = 4.19). intercropping of two rows of pea in between two rows of maize with two hand weeding at 20 and 40 dae to be a promising practice for weed suppression and profitable maize + legume intercropping in rabi season. introduction maize stands third position among cereal crops in bangladesh and also in total production covering an area of 1.52 lac ha with an annual production around 8.87 lac m ton (bbs, 2011). in bangladesh, the maximum grain yield of 14 t/ha from hybrid maize in rabi season was reported by farid and shil (2006). various causes are responsible for reducing yield. among the causes weed is the major factor for low yield of maize. weeds are one of them (karimmojeni et al., 2010). weeds compete with plant nutrients, soil moisture, light and space against crop plants (kandasamy, 2017). although appropriately selected herbicides may perform an important role in weed reduction, increasing weed resistance to herbicides, high cost and negative effects of herbicides on environment have increased the need of non-chemical weed control in agro-ecosystems (ahmad et al., 2013).weed competition is high when maize crop is sown with wide spacing, which allows a high portion of ambient light to penetrate. it is possible that maize could be intercropped with a short-duration legume crop, however, to fill the uncovered spaces between the rows and thus (legume crop) act as the suppressed weed. about:blank 34 naher et al. intercropping is widely practiced in the tropical and subtropical asian countries because of its increased productivity and insurance against crop failure. it also helps to reduce weed populations, insect, pests infestation and risk of complete crop failure (islam et al., 2013). intercropping is an agricultural practice which can be used for decreasing the dependency on chemical herbicides in weed control (banik et al., 2006) and defined as the growth of two or more crop species simultaneously in the same field during a growing season (thayamini and brintha, 2010). maize based intercropping systems are often subjected to severe stress offered by weed. several researchers have been reported on intercropping (ijoyah, 2012) and mostly focusing on cereal-legume based (hugar and palled, 2008). legumes can relocate fixed n to intercropped cereals through their joint growing period and this n is an imperative resource for the cereals (bhagad et al., 2006).maize suffers from severe weed competition and depending upon the intensity, nature, stages and duration of weed infestation, it causes yield losses from 28-100% (patel et al., 2006). weed suppression in intercropping system, and more efficient use of environmental resources by component crops had been reported (mashingaizde, 2004). in addition, weeds can deplete nutrients from soils (sreenivas and satyanarayana, 1996). herbicides have simplified weed control and are extensively used, even replacing cultural weed control methods in several regions. intercropping can suppress the weed growth more than the sole crops (baumann et al., 2000). there is only limited information available on herbicide-free weed management practices that provide adequate weed suppression while maintaining acceptable yields on weed suppression. therefore, the objective of this study was to select the suitable legume crop in the intercropping system for maximum weed suppression and increased yields. materials and methods the experiment was conducted at the on-farm research field of bangladesh agricultural research institute, joydebpur, gazipur during rabi season of 2010-11. the experiment site was located at chhiata series under agro-ecological zone28. before opening the land, the soil samples were taken from the spots of the experimental area and analyzed from the soil science division, bari. the soil analysis showed that the soil of the experimental field was loam in texture and low in organic matter (1.16%). the soil ph is 7.2 and contained very low amount of total nitrogen (0.061%), phosphorus (3 g g-1), sulphur (0.6 µg g-1), zinc (3.54 µg g-1), boron (0.44 µg g-1) and potassium (0.13 meq. /100 g soil).the rainfall during the period was 189 mm in 2010-11. during the crop growth period average monthly maximum temperature was recorded in the month of april (22.5 °c) and the minimum was recorded in the month of january 10.51 °c in 2010-11.there were 17 treatments viz., sole maize (no weeding) = t1, maize + garden pea (no weeding) = t2, maize + garden pea (one hand weeding at 20 dae) = t3, maize + garden pea (one hand weeding at 40 dae) = t4, maize + garden pea (two hand weeding at 20 and 40 dae) = t5, maize + bushbean (no weeding) = t6,maize + bushbean (one hand weeding at 20 dae) = t7, maize + bushbean (one hand weeding at 40 dae) = t8, maize + bushbean (two hand weeding at 20 and 40 dae) = t9, maize + cowpea (no weeding) = t10, maize + cowpea (one hand weeding at 20 dae) = t11, maize + cowpea (one hand weeding at 40 dae) = t12, maize + cowpea (two hand weeding at 20 and 40 dae) = t13, sole maize (weed free) = t14,sole garden performance of legumes on weed suppression with hybrid maize intercropping 35 pea (weed free) = t15, sole bushbean (weed free) = t16 and sole cowpea (weed free) = t17 were studied. maize was sown in 75 cm  20 cm spacing both in sole and intercrop system. planting arrangement in intercrop treatments, two rows of legumes accommodated between maize rows.the trials were laid out in a randomized complete block design with three replications. the plot size was 5.0m  4.5m. maize var. bari hybrid maize-7, garden pea var. bari motorshuti-1, bushbean var. bari jharsheem-1 and cowpea var. bari felon-1 were used as test crops. fertilizer was applied for maize at the rate of 250-50100-44-5-2 kg of n, p, k,s, zn and b ha-1, respectively, from urea, triple super phosphate, murate of potash, gypsum, zinc sulphate and boric acid, respectively. half amount of n and full dose of other fertilizers were incorporated into the soil at the time of final land preparation. the remaining urea was top dressed in two equal installments as top dressing at 8-10 leaf stage (30-35 das) and at tasseling stage (50-60 das) followed by irrigation. fertilizers were applied for sole pea, bushbean and cowpea at the rate of 23-30-8, 12-9-13, 23-33-55 kg of n, p, k ha-1, respectively from urea, tsp, mop, gypsum, zinc sulphate and boric acid, respectively. half amount of urea and full amount of other fertilizers were applied at the time of final land preparation. sowing of both maize and legumes were done on 27 november 2010. weed management was done as per treatment specification. green pods of pea and bushbean were manually collected in three installments at 55, 65 and 70 dae while cowpea was harvested at 125 dae. maize was harvested at 155 dae. legume equivalent yield and maize equivalent yield were computed using the formula of bandyopadhaya (1984). legume equivalent yield = yil + (yim× pm) / pl maize equivalent yield = yim + (yil × pl)/pm where, yil = yield of intercrop legume (t ha-1) yim = yield of intercrop maize (t ha-1) pm = selling price of maize pl = selling price of legume land equivalent ratio (ler) land equivalent ratio (ler) was obtained according to willey (1979) as follows: ler = yield of mazie as intercrop yield of maize as sole crop + yield of legume as intercrop yield of legume as sole crop competitive ratio (cr) (willey and rao, 1980) competitive ratio of maize: (crm) :{(yim/ysm)/yil/ysl)} × (zl/zm) competitive ratio of legume: (crl) : {(yil/ysl)/(yim/ysm)} × (zm/zl) where, ysm = yield of sole maize ysl = yield of sole legume yim = yield of intercrop maize yil = yield of intercrop legume zi= proportion of legume in intercrop zm= proportion of maize in intercrop weed control efficiency (wce) was calculated using the following formula (curz et al., 1986). wce = 100 dwc dwt-dwc × dwc = dry weight of weeds in the weedy check dwt = dry weight of weeds in the weeding treatment the collected data were statistically analyzed by using mstat program and the means were adjudged by using lsd. economic analysis was also done. 34 naher et al. results and discussion weed density and weed dry weight were significantly affected by different intercropping systems and weeding regime (table 1).the weed population was dominated by grasses with little contribution from broadleaf and sedges. cynodon dactylon, eleusine indica, echinochloa crus-galli, cyperus rotundus, leersia hexandra, enhydra fluctuans, portuloca oleracea, vicia sativa, rumex maritimus were the common species dominating the community in the experimental plots. the highest weed population (2527337 and 162.7 at 20 dae, 40 dae and at harvest, respectively) and weed dry weight (59.62, 108.80 and 40.40g m-2 at 20 dae, 40 dae and at harvest, respectively) was found in no weeding sole maize (t1) and the lowest in t5 {maize + pea (weeding at 20 and 40 dae)} treatment. similar results were obtained by islam (2002) and liebman and dyek (1993). among the intercropping systems, the maximum weed population and weed dry biomass were recorded in (t10) maize + cowpea with no weeding. this might be due to the slow initial growth and widen row spacing of cowpea which provided with the conductive condition for growth of weeds (singh et al., 1980). table 1. weed density and weed dry weight in different maize + legumes intercropping systems during the rabi season of 2010-11 treatment weed density (no. m-2) weed dry weight (g m-2) 20 dae 40 dae at harvest of legumes 20 dae 40 dae at harvest of legumes t1 252.7 a 337.0 a 162.7 a 59.62 a 108.8 a 40.40 a t2 192.0 fg 238.3 cd 117.7 c 41.54 bcd 61.63 b 30.58 c t3 201.0 def 49.33 ef 59.33 ef 42.37 b 10.64 de 15.81 f t4 194.3 efg 228.0 d 45.67 g 40.88 bcd 50.55 c 11.28 g t5 186.3 g 41.00 f 22.67 i 39.96 d 8.52 e 6.57 h t6 203.3 cde 262.0 b 138.7 b 40.23 d 62.95 b 31.68 bc t7 207.0 bcd 52.33 ef 72.00 d 42.04 bc 13.38 d 20.46 e t8 210.7 bc 241.3 cd 62.00 e 40.87 bcd 53.87 c 14.12 f t9 204.3 cd 60.00 e 29.00 hi 40.19 d 11.48 de 7.31 h t10 209.0 bcd 263.0 b 141.3 b 39.95 d 61.73 b 32.48 b t11 205.7 bcd 60.33 e 72.33 d 40.47 cd 13.47 d 24.25 d t12 214.7 b 252.7 bc 54.33 f 41.20 bcd 51.71 c 14.57 f t13 207.3 bcd 55.00 ef 35.00 h 40.99 bcd 11.42 de 7.53 h lsd (0.05) 9.343 15.09 7.598 1.711 4.484 1.862 cv (%) 2.90 5.88 6.26 2.59 7.19 6.04 t1= sole maize (no weeding), t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4= maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6= maize + bushbean (no weeding), t7= maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae) weed control efficiency of different treatments varied from 15-26.18% at 20 dae, 22-87.8% at 40 dae and 13-86% at harvest (table 2). the highest weed control efficiency (wce) was recorded in maize + pea (86.14%) followed by maize + bushbean (82.19%) and maize + cowpea (78.46%) intercropping. among the intercropping systems, un-weeded maize + cowpea (13-22%) intercropping plot gave the lower wce. among all the weed control treatments, maize + pea performance of legumes on weed suppression with hybrid maize intercropping 35 with two hand weeding had the highest weed control efficiency (26-88%) while it was 19-82% at maize + bushbean and 18-83% at maize + cowpea treatment. the maximum weed control efficiency was associated with maize + pea intercropping, and it was minimum with maize + cowpea intercropping system. the reduction in weed population and weed dry biomass in intercropping systems may be attributed to shading effect and competition stress created by canopy of more number of crop plants in a unit area having suppressive effect on associated weeds. similar results were reported by kumar and reddy (2000). table 2. weed control efficiency (%) of different intercropping systems under varying weeding regimes during the rabi season of 2010-11 treatment 20 dae 40 dae at harvest of legumes t2 24.02 ab 29.30 cd 27.60 f t3 20.39 bcd 85.36 ab 63.39 d t4 23.09 abc 32.33 c 71.85 c t5 26.18 a 87.82 a 86.14 a t6 19.49 cde 22.28 e 14.71 g t7 18.08 def 84.47ab 55.72 e t8 16.58 ef 28.42 cd 61.88 d t9 19.13 de 82.20 b 82.19 ab t10 17.24 def 21.96 e 13.13 g t11 18.60 def 82.09 b 55.55 e t12 15.00 f 25.01de 66.63 d t13 17.95 def 83.68 ab 78.46 b lsd (0.05) 3.789 4.553 4.833 cv (%) 11.39 4.85 5.06 t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4= maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6= maize + bushbean (no weeding), t7= maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae) effect on maize yield and yield attributes yield and yield contributing characters of maize were influenced significantly by different intercropping systems and weeding regime treatment (table 3). the maximum length of cob (19.37) was recorded in weed free sole maize (t14) which was statistically similar with maize + pea intercropping with two hand weeding (18.37 cm) and no weeding sole maize (18.30). the lowest cob length (15.27 cm) was obtained from no weeding maize + cowpea intercropping systems which was statistically at par with no weeding maize + pea and maize + bushbean intercropping systems (16.23 cm and 16.30 cm). higher number of grains cob-1 was recorded from weed free sole maize (593.3) which was statistically identical to maize + pea with two hand weeding and maize + bushbean intercropping systems. the lowest grains cob-1 was in no weeding maize + cowpea association. the highest 1000-grain weight was obtained from weed free sole maize (312.5 g) than unweeded sole maize plot (258.5 g). among the intercropping systems, maize + pea produced higher grain weight (295.2 g) than maize + bushbean and maize + cowpea association. lower 1000grain weight was obtained from maize + cowpea association. table 3. yield attributes of maize in maize + legumes intercropping systems during the rabi season of 2010-11 34 naher et al. treatment cob length (cm) no. of grains cob-1 1000-grain wt. (g) t1 18.30 ab 567.0 abc 258.5 e t2 16.23 de 484.0 gh 278.6 bcde t3 16.73 cd 502.7 fg 285.0 bcd t4 17.67 bc 560.7 bcd 285.0 bcd t5 18.37 ab 585.7ab 295.2 ab t6 16.30 de 475.7 h 272.5 bcde t7 17.27 bcd 542.0 cde 275.5 bcde t8 17.77 bc 563.0 bc 277.1bcde t9 17.87 bc 575.3 ab 289.9 abc t10 15.27 e 421.0 i 256.7e t11 16.60 cd 519.0 ef 264.0 de t12 16.77 cd 519.3 ef 269.0 cde t13 16.70 cd 535.7de 287.2 bc t14 19.37 a 593.3 a 312.5a lsd (0.05) 1.141 24.52 22.759 cv (%) 3.95 2.75 4.86 t1= sole maize (no weeding), t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4 = maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6 = maize + bushbean (no weeding), t7 = maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae) significant influence was observed in grain yield of maize under different intercropping systems (fig. 1). the highest grain yield (8.80 t ha-1) was obtained from weed free sole maize while the lowest yield (4.64 t ha-1) showed in unweeded maize + cowpea intercropping plot. among the intercropping systems maize + pea with two hand weeding at 20 and 40 dae recorded highest grain yield than all other intercropping treatments. fig. 1. grain yield of maize in maize + legumes intercropping systems during the rabi season of 2010-11 when maize was intercropped with pea, higher grain yield was obtained (7.58 t ha-1) than that of maize + bushbean and cowpea intercropping association. this might be due to less inter-species competition for nutrient especially nitrogen between maize and pea, in addition, as a leguminous crop pea supplies 0 2 4 6 8 10 g ra in y ie ld ( t h a1 ) treatments performance of legumes on weed suppression with hybrid maize intercropping 35 supplementary nitrogen to maize that aided to gain statistically similar grain yield of maize. the results are in agreement with those of singh et al. (2000). yield and yield attributes of legumes yield and yield attributes of legumes were significantly influenced by the treatments (table 4). pods per plant were significantly influenced by intercropping systems with varying weeding regime. higher number of pods per plant was observed in maize + bushbean with two hand weedings (13) intercropping systems which was statistically similar with all the treatments of maize + bushbean intercropping and respective sole crop. sole treatments showed higher pods per plant. reduced inter and intra species competition for growth factors might have contributed towards higher number of pods per plant of sole legume..higher pod yield was produced from maize + bushbean intercropping system (9.13 t ha-1) with two hand weeding which was followed by one hand weeding at 20 dae (8.23 t ha-1) and 40 dae (7.63 t ha-1), respectively (fig. 2). within maize + pea intercropping two hand weeding gave higher pod yield (4.93 t ha-1) than one hand weeding at 20 dae (4.43 t ha-1), at 40 dae (4.30 t ha-1) and no weeding treatment (3.1 t ha-1). weed free sole cowpea gave higher grain yield (0.59 t ha-1) than cowpea with two and one hand weeding treatments. no hand weeding gave lower grain than the sole situation. besides, sole legume grown in sufficient sunlight due to higher photosynthesis occurred at the vegetative to pod formation stage then more carbohydrate was translocated to pod, so pod yield was higher. sarker and pal (2004) and razzaque et al. (2007) also reported higher pod yield of groundnut was obtained from sole crop. the pod yield of legumes in intercropping situation was considerably reduced. this corroborates with the findings of sarkar and pal (2004) and razzaqueet al. (2007). table 4. yield attributes of legumes in maize + legumes intercropping system during the rabi season of 2009-10 treatment pods plant-1 (no.) pod length (cm) t2 7.333 cde 6.933 e t3 8.333 cd 7.367de t4 9.000 bc 7.833 de t5 11.000 ab 7.600 de t6 12.330 a 10.400 c t7 11.330 ab 10.700 c t8 11.670 a 10.730 c t9 13.000 a 10.670 c t10 6.333 de 12.600 b t11 5.667 e 12.870 ab t12 6.667 cde 13.630 a t13 7.667 cde 13.770 a t15 12.330 a 8.067d t16 12.000 a 12.170 b t17 11.670 a 12.700 b lsd (0.05) 2.234 0.869 cv (%) 13.69 4.93 34 naher et al. fig. 2. seed yield of legumes in maize + legumes intercropping system during the rabi season of 2010-11 t1= sole maize (no weeding, t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4 = maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6 = maize + bushbean (no weeding), t7 = maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae), t15 = sole garden pea (weed free), t16= sole bushbean (weed free), t17= sole cowpea (weed free) assessment of competition and evaluation of intercrop productivity competitive ratio: competitive ratio (cr) values showed the variability in competitive ability of component crops with the variation of intercropping (table 5). the results indicated that maize was a better competitor when it was sown with pea and bushbean and a poor competitor when it was sown with cowpea. in maize + pea intercropping with different weeding regimes, maize with no weeding treatment showed higher competition to pea and to weeds. it was followed by one weeding at 20 dae and two weeding at 20 and 40 dae. in maize + bushbean intercropping, maize was better competitor when two hand weeding were done. similar results were also obtained by patra et al. (2000). the difference in competitive ratio of maize and legumes in maize + cowpea intercropped was minimum indicating similar competitive ability of maize and cowpea. land equivalent ratio (ler) the highest land equivalent ratio (ler) was recorded in maize + pea (1.89) with two hand weedings. the lowest ler value was found in maize + cowpea with no weeding (1.29) treatment. ler 1.89 indicates that 89 percent yield advantage is obtained when grown as intercrops compared to growing sole crops (table 5).the results are in agreement with that of quayyum et al. (1987), patra et al. (2000), santalla et al. (2001) and razzaque et al. (2007). 0 2 4 6 8 10 12 s ee d yi el d (t h a1 ) treatments performance of legumes on weed suppression with hybrid maize intercropping 35 table 5. competitive ratio and ler of maize and legumes in intercropping systems in the rabi season of 2010-11 treatment competitive ratio land equivalent ratio (ler) maize legume difference t1 pea 1.00 t2 1.17 0.85 + 0.32 1.30 t3 1.04 0.96 + 0.08 1.53 t4 1.02 0.98 + 0.04 1.74 t5 1.09 0.91 + 0.18 1.89 bush bean t6 1.01 11.80 + 0.02 1.26 t7 1.02 13.10 + 0.04 1.42 t8 1.14 13.83 + 0.17 1.61 t9 1.12 1.27 + 0.23 1.69 cowpea t10 0.83 0.99 0.39 1.29 t11 0.86 0.98 0.31 1.43 t12 0.83 0.87 0.38 1.54 t13 0.89 0.89 0.24 1.67 t14 1.00 t15 1.00 t16 1.00 t17 1.00 t1= sole maize (no weeding, t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4 = maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6 = maize + bushbean (no weeding), t7 = maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae), t15 = sole garden pea (weed free), t16= sole bushbean (weed free), t17= sole cowpea (weed free) intercrop efficiency based on equivalent yield and benefit cost the performance of maize + legume intercropping systems was also evaluated based on equivalent yield (bandyopadhyay, 1984). the maximum maize equivalent yield (20.12 t ha-1) was obtained from t5 (maize + pea with two hand weeding at 20 and 40 dae) treatment (table 6). lower maize equivalent yield (6.35 t ha-1) was obtained from t10 which was followed by t11 (7.03 t ha -1), t1 (6.50 t ha-1) and t12 (7.99 t ha -1), respectively. on the other hand, among the intercrop bushbean equivalent yield was higher than pea and cowpea. lower legume equivalent yield (0.6 t ha-1) was obtained in sole crop of cowpea (t17). many plant studies also reported higher economic advantage in intercropping system than sole crop (saha et al., 2001 and begum et al., 2010). table 6 showed that the highest gross return (tk. 90347 ha-1) was obtained from maize as sole with weed free condition (t14). pea in sole situation also showed much higher gross return (tk. 175340 ha-1) than other bushbean and cowpea. among intercropping, maize + pea with two hand weeding treatment gave higher gross return in both maize and pea crops which was followed by maize + bushbean with two hand weeding. higher total gross return of tk. 203263 ha-1 was obtained from the same treatment in intercropping situation than any other sole crop cultivation. the highest cost of cultivation was noted in sole pea and bushbean treatment (tk. 65900 ha-1) and the lowest cost of cultivation of tk. 20300 ha-1 was recorded from sole cowpea. net return varied from tk. 9035 to 154748 ha-1 among the treatments. the highest net return was recorded from maize + pea intercropping with two hand weeding (tk. 154748 ha-1). 34 naher et al. table 6. equivalent yield and cost benefit analysis of different maize + legume intercropping systems during rabi season of 2010-11 treatment equivalent yield (t ha-1) gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr maize legume t1 6.50 70505 40500 30005 1.74 t2 13.52 6.76 136968 45515 91453 3.01 t3 16.52 8.26 167143 47550 119593 3.52 t4 17.62 8.81 178080 47500 130580 3.75 t5 20.12 10.06 203263 48515 154748 4.19 t6 10.45 10.45 106289 45515 60774 2.34 t7 11.80 11.80 119812 47500 72312 2.52 t8 13.10 13.10 132863 47500 85363 2.80 t9 13.83 13.83 140079 49515 90564 2.83 t10 6.35 1.27 65330 39000 26330 1.68 t11 7.03 1.41 72065 40000 32065 1.80 t12 7.59 1.52 77674 40000 37674 1.94 t13 8.25 1.65 84352 42515 41837 1.98 t14 90347 45515 44832 1.98 t15 8.77 175340 55000 120340 3.19 t16 11.03 110300 55000 55300 2.01 t17 0.59 29335 20300 9035 1.45 t1= sole maize (no weeding, t2= maize + garden pea (no weeding), t3= maize + garden pea (weeding at 20 dae), t4 = maize + garden pea (weeding at 40 dae), t5= maize + garden pea (weeding at 20 and 40 dae), t6 = maize + bushbean (no weeding), t7 = maize + bushbean (weeding at 20 dae), t8= maize + bushbean (weeding at 40 dae), t9= maize + bushbean (weeding at 20 and 40 dae), t10= maize + cowpea (no weeding), t11= maize + cowpea (weeding at 20 dae), t12= maize + cowpea (weeding at 40 dae), t13= maize + cowpea (weeding at 20 and 40 dae), t15 = sole garden pea (weed free), t16= sole bushbean (weed free), t17= sole cowpea (weed free) the highest bcr was found in maize + pea with two hand weeding (4.19) whereas sole cowpea and maize + cowpea with no weeding intercropping gave the lowest bcr than any other treatments (1.45 to 1.68). conclusion the results revealed that intercropping of two rows of pea in between two rows of maize (75 cm x 20 cm) with two hand weeding at 20 and 40 dae to be a profitable practice for weed-suppression and a higher economic return. references ahmad, m., m.j. khan and d. muhammad. 2013. response of maize to different phosphorus levels under calcareous soil conditions. sarhad j. agric. 29(1): 43-48. bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. banik, p., a. midya, b.k. sarkar and s.s. ghose. 2006. wheat and chickpea intercropping systems in an additive series experiment: advantages and weed smothering. eur. j. agron. 24 325-332. baumann, d.t., m.j.kropf and l.bastiaans 2000: intercropping leeks to suppress weeds. weed res. 40: 361-376. performance of legumes on weed suppression with hybrid maize intercropping 35 bbs, 2011. yearbook of agricultural statistics. bangladesh bureau of statistics, ministry of planning. govt. of the people’s republic of bangladesh. pp.35. begum, s., islam, m.n., rahman, m. t., chowdhury, j. a. and haque, m.i. 2010. suitability study of different chili varieties for intercropping with sweet gourd. j. exp. biosci. 1(2): 1-4. bhagad, s.b., s.a. chavan, m.v. zagade and a.v. dahiphale. 2006. intercropping groundnut and sweet corn at different fertility levels and row proportions. indian j. crop sci. 1(1-2): 151-153. cruz, f.d., k. moody and m.b.d. ramas. 1986. reducing variability sampling weeds in upland rice (oryza sativa). philopp j. weed sci. 13: 56-59. farid, a.t.m. and n.c. shil 2006. nutrient management for hybrid maize cultivation in bangladesh. in: hybrid maize production technology. training manual. development of hybrid maize research project. plant breeding division, bangladesh agril. res. inst. 24p. hugar,h.y.and y.b. palled. 2008. effect of intercropping vegetables on maize associated with weeds in maize-vegetable intercropping systems. karnakata. j. agric. sci. 21(2): 159-161. ijoyah, m.o. 2012. review of intercropping research on cerealvegetable based cropping system.scientific j. crop sci. 1(3): 55-62. islam, m.n. 2002: competitive interference in a maize-bush bean intercropping systems. ph.d. dissertation. bangladesh sheikh mujiburrahman agricultural university, salna, gazipur-1703. islam, m.n., rahman, m. s., ahmed, f., alom, m.s. and akhteruzzaman, m. 2013. performance of different hyv mustard varieties with sugarcane (sacchaarum officinarum) as intercrop in farmers’ fields. bangladesh j. agril. res. 38(1): 137-143. kandasamy, s. 2017. effect of weed management practices on weed control index, yield and yield components of sweet corn. j agri res. 2 (4):000139. karimmojeni, h., h.r.mashhadi, h. m. alizadeh, r.d. cousens and m.b.mesgaran. 2010. interference between maize and xanthium strumarium or datura stramonium. weed res. 50: 253-261. kumar, k.a. and m.d. reddy. 2000. integrated weed management in maize + turmeric intercropping systems. indian j. weed sci. 32 (1&2) :59-62. liebman, m. and e. dyek. 1993. crop rotation and intercropping strategies for weed management. ecol. appl. 3 : 92–122. mashingaidze, n. 2004. the effect of detassilling and leaf stripping on productivity and weed pressure in a maize-bean intercrop in chinyika resettlement area. msc. thesis, crop science department, university of zimbabwe. pp. 88. patel, v.j., p.n. upadhyay, j.b. patel and m.i.meisuriya. 2006. effect of herbicide mixture on weeds in kharif maize (zea mays l.) under middle gujarat conditions. indian j. weed sci. 38(1&2): 54-57. patra, b.c., b.k. mandal and a.l.padhi.2000: production potential of winter maize (zea mays l.) based intercropping systems. indian j. agril.sci.70(4): 203-206. quayyum, m.a., m.e.akanda and m.f. karim. 1987: row spacing and number of rows of chickpea grown in association with maize (zea mays l.) bangladesh j. agril.res.12(4) 223-230. 34 naher et al. razzaque, m.a., s.rafiquzzaman, m.m. bazzaz, m.a. ali and m.m.r. talukdar. 2007: study on the intercropping groundnut with chill at different plant populations. bangladesh j. agril. res. 32(1) 37-43. saha, r.r., m.a.quayyum, s.alom, p.c.sarker, a.khayer, a.f.m.f. rahman.2001: fertilizer management in hybrid maize with soybean intercropping system under irrigated condition. j. bio. sci. 1(9) 812-814. santalla, m., a.p. rodino, p.a. casquero and ronamde 2001: interactions of bushbean intercropped with field and sweet corn. europ. j. agron.15 185196. sarker. r.k. and p.k. pal. 2004: effect of intercropping rice (oryza sativa) with groundnut (arachishypogaea) and pigeonpea (cajanuscajan) under different row orientations on rainfed uplands. indian j. agron.49(3)147-150. singh, d.p., n.s. rana and r.p. sing. 2000: growth and yield of winter maize as influenced by intercrops and nitrogen application. indian j. agron.45(3) 515519. singh, h.p., m.c. saxena and j.p.sahu. 1980: harvest index in relation to yield in (legume). tropical grain legume 17/18: 6-8. sreenivas, g. and v. satyanarayana. 1996. nutrient removal by weeds and corn. ind. j. agron. 41(1) 160-162. thayamini, h.s. and i.brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135-145. willey rw 1979: intercropping: its importance and research needs. field crops abs. 32(1) 1-10. willey rw, rao mr 1980: a competitive ratio for quantifying competition between intercrops. expl. agric. 16 117-125. bangladesh agron. j. 2017, 20 (1): 45-56 effect of age and storage duration of seedling on growth and yield of wet season rice p saha1, msu bhuiya2, b karmakar1*, m salim2 , b ahmed1, p shil3 and sk roy4 1bangladesh rice research institute, gazipur, bangladesh. 2bangladesh agricultural university, mymensingh, bangladesh. 3agriculture studies, model shool and college, boyra, khulna. 4agriculture studies, khulna public college, boyra, khulna. * corresponding author's email: biswajitbrri@gmail.com key words: shoot, root, biomass, leaf area index, crop growth rate. abstract the experiment was conducted at the agronomy research field of bangladesh agricultural university, mymensingh from july to december 2013 to find out the effect of seedling age and storage duration on growth and yield of wet season rice. the experiment comprised of four ages of seedling (25, 30, 35 and 40-d-old) and four storage durations (0, 1, 2 and 3-days) of uprooted seedlings. rice var. brri dhan52 was used as a test variety. the experiment was laid out in a split-plot design with 3 replications placing seedling age in the main plot and storage duration in the subplot. the effect of age and storage -duration of seedling, and their interaction were significant on growth parameters (shoot height, root length, number of tillers hill-1, leaf area index and crop growth rate), grain yield and straw yield. the growth parameters and yield exhibited a trend of decrease with the increase in seedling age and storage duration. all the growth parameters and yield showed highest value in the younger seedlings of 25-d-old with 0-day storage duration of uprooted seedlings while the lowest in the older seedlings of 40-d-old with 3-days of storage duration. the var.brri dhan52 produced the highest lai (8.23), cgr (7.33 mg day-1 hill-1) and biomass (26.87 g) at 60, 45 and 60 days after transplanting. grain yield reduced by 13, 19 and 37% of 30, 35 and 40-d-old seedlings, respectively compared to 25-d-old seedlings. in case of seedling storage, grain yield reduced by 5, 14 and 31% of 1, 2 and 3-d storage, respectively compared to 0-d storage. for optimum growth and yield of wet season rice, 25-d-old seedlings may be stored up to 1-day after uprooting taking into account the possible delay in transporting seedlings to the flood affected area from the nearby districts. introduction rice is the most important and extensively cultivated grain crop of bangladesh. among the groups of rice, transplanted aman rice covers the largest area of 5.60 million hectares (49.08 % of the total rice area) and contributes to 38.10% (12.89 million tons) of the total rice production in the country (bbs, 2013). the bangladesh agriculture is prone to numerous risks and hazards like drought, salinity, excessive rainfall, flood, storm, flash flood and so on. the magnitude and frequency of flood and flash flood throughout the country are still alarming. crop damage due to early or flash flood is very common feature in bangladesh. due to unexpected incessant rainfall or flash flood during wet season (aman), most of the cultivated lands of low lying area go under water causing severe damage to the rice seedlings in the freshly transplanted fields. as a result, an acute shortage of rice seedlings occurs frequently when the floodwater recedes. farmers in flood prone areas face difficulty in double transplanting due to unavailability of seedlings. sometimes, seedlings age is so young or too old 46 saha et al. which would not be suitable for good harvest. at that time, rice seedlings of optimum age may be required to transport to the flood affected area from the nearby districts which may take 2 to 3 days. so, the optimum age and storage duration of uprooted seedling may contribute significantly to the growth and yield of wet season rice. therefore, the optimum age and storage duration of uprooted seedling in the flood prone areas can play a significant role on the growth and yield of transplant aman rice. therefore, the present study was undertaken to determine the optimum age of seedlings on storage effect exerted in wet season rice and investigate the effect of age and storage of seedlings on growth and development of wet season rice. materials and methods the experiment was conducted during the period from july to december 2013 at the agronomy field laboratory of bangladesh agricultural university (bau), mymensingh (24°75’ n latitude and 90°50’ e longitude at an elevation of 18 m above the sea level). the soil of the experimental land belong non-calcareous dark grey flood plain type under the old brahmaputra alluvial floodplain of aez-9. the land was medium high with sandy loam texture having a soil ph of 6.40, moderate in organic matter content. the experimental field is situated under subtropical climate. usually the rainfall is heavy during kharif season (april to september). rice var. brri dhan52, a high yielding submergence tolerant variety, was used in the experiment. the experiment consisted of two factors viz., seedling age (25, 30, 35 and 40-d-old seedlings) and storage duration of seedling after uprooting (0, 1, 2, and 3 days). the experiment was laid out in a split-plot design with 3 replications assigning seedling age in the main plots and storage duration in the sub-plots. the sprouted seeds were sown in the wet nursery bed on four dates viz., 26 june, 1 july, 6 july and 11 july in 2013 to obtained 40, 35, 30 and 25 day old seedlings for transplanting. proper care was taken to raise the seedlings in the seedbed. weeds were removed and irrigation was given in the nursery bed as and when necessary. the experimental land was prepared in puddle condition through ploughing and cross ploughing four times with a country plough followed by laddering to level the soil. the fertilizers urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum were applied experimental plots @ 195, 52, 82 and 60 kg ha-1, respectively (brri, 2011). the entire amounts of tsp, mop and gypsum were applied as basal dose at the time of final land preparation. urea was top dressed in three equal splits at 15, 35 and 50 days after transplanting (dat). the nursery bed was made wet by applying water on the previous days before uprooting the seedlings. the seedlings were uprooted carefully from nursery bed on 2, 3, 4 and 5 august 2013 without causing much mechanical injury to the roots and stored separately on the shade before transplanting for 3, 2, 1 and 0 day, respectively, as per treatments. seedlings of 40, 35, 30 and 25 days with the combination of storage duration of 3, 2, 1 and 0 days were transplanted in the main field on 5 august, 2013 with 3 seedlings hill-1 at 25 x 15 cm spacing. uniform management practices were followed for all the treatments. sampling was started from 15 dat and continued up to 60 dat at 15 day intervals. five hills were randomly selected and marked with the bamboo sticks in each unit plot excluding border rows. data on plant height, shoot height, root length, number of tillers hill-1, leaf area index (lai), total dry matter (g hill-1), crop growth rate (cgr), yield and yield components were collected . leaf area index (lai) and crop growth rate (cgr) were calculated from the following formula expressed by yoshida (1981) and hunt (1978). 47 effect of age and storage duration of seedling on growth and yield of wet season rice leaf area index (lai): the leaf area was measured by an automatic leaf area meter (type aan-7, hayashi dam ko co., japan). leaf area index was calculated as the ratio of total leaf area and total ground area of the sample following formula expressed by yoshida (1981) and hunt (1978). lai = p la where, la= total leaf area of the leaves of the sampled plant (m2) and p= area of the ground surface covered by the plant (m2) crop growth rate (cgr): crop growth rate refers to the increase of plant dry matter per unit of time following the formula of yoshida (1981) and hunt (1978). cgr = 12 12 tt ww where, w1 = total dry matter hill-1 at time t1 and w2 = total dry matter hill-1 at time t2 and (t2 t1)= time difference of two consecutive harvests. the collected data were statistically analyzed using mstat and mean differences among the treatments was adjudged by dmrt (gomez and gomez, 1984). results and discussion shoot height shoot height was significantly influenced by seedling age, storage duration of uprooted seedlings and their interaction at 45 and 60 dat (table 1). the highest shoot height was obtained at all sampling dates when 25-d old seedlings were transplanted without storage. the shoot height exhibited a trend of decrease with the increase of age and storage durations of uprooted seedlings at all sampling dates. similar results were found by paul et al. (2003) and kaykobad (2001). this reduction in shoot height might be due to better growth and vigor of the 25-d-old seedlings after transplanting. the recovery of transplanting shock is much better in younger seedlings compared to the older ones. shoot height gradually decreased in older seedlings at all sampling dates. in general, interaction of seedling age and storage duration followed the similar trend of higher shoot height in younger seedlings without storage in all the sampling dates. huridal et al. (1999) also obtained the similar results. root length seedling age, storage duration and their interaction had significant effect on root length at 45 and 60 dat but it remained insignificant at 15 and 30 dat (table 1). the longest root length was obtained at all sampling dates when 25-d-old seedlings were transplanted and the shortest root length was recorded at all sampling dates when 40 day old seedlings were transplanted (table 1). these findings are in conformity with bali and uppal (1999). the longest root length was obtained at all sampling dates with 0-d of storage duration and the shortest root length was obtained at all sampling dates with 3-days of storage duration. these findings agree to those of islam (1995). the recovery of transplanting shock and root formation is much better in younger seedlings compared to the older ones. root length was gradually increased up to 45 dat and decreased at 60 dat in all seedling ages irrespective of younger or older ones. this 48 saha et al. might be due to the tendency of the plant to restrict its root system within the nutrient rich top soil after the completion of establishment of the plant. root length was gradually decreased as the age of seedlings increased at all sampling dates. furthermore, it was gradually increased up to 45 dat but decreased at 60 dat in all cases of storage durations. the root length exhibited a trend of decrease with the increase in storage durations of uprooted seedlings from 0 to 3 days at all sampling dates. interaction of age and storage of seedlings showed that 25-d-old seedlings with 0-d storage had higher root length compared to the older and stored seedlings. this indicates that both the age of seedlings and storage duration influenced root length negatively. tillers production hill-1 number of tillers hill-1 was significantly influenced by seedling age, storage duration and their interaction at 30, 45 and 60 dat (table 2). the mean highest number (12.3) of tillers hill-1 was obtained at all sampling dates when 25-d-old seedlings were transplanted and the lowest number (9.6) of tillers hill-1 was obtained at all sampling dates when 40-d-old seedlings were transplanted. tillers hill-1 was gradually increased up to 45 dat but decreased at 60 dat in all seedling ages irrespective of younger or older ones. this might be due to the internal mechanism of the plant to produce the maximum number effective tillers hill-1 by eliminating the non-vigorous tillers. number of tillers hill-1 was gradually decreased as the age of seedlings increased at all sampling dates (table 2). similar result was also observed by haque (2002). the maximum number of tillers hill-1 was obtained at all sampling dates with 0 day of storage duration and the minimum number of tillers was obtained at all sampling dates with 3 days of storage duration. this finding was justified by islam (1995). number of tillers hill-1 was gradually increased up to 45 dat but decreased at 60 dat in all cases of storage durations. number of tillers hill-1 exhibited a trend of decrease with the increase in storage durations of uprooted seedlings from 0 to 3 days at all sampling dates (table 2). at all sampling dates, the maximum tillers hill-1 was obtained in 25-d-old seedlings with 0 day storage duration while the lowest tillers hill-1 was found in 35-d-old seedlings with 3 days storage duration at 30 dat. forty-d-old seedlings gave the lowest tillers hill-1 at 45 and 60 dat with 1 and 3 day storage duration, respectively (table 2). this might be the cumulative effect of old age of seedlings with longer duration of storage. both the factors discouraged early growth of tillers due to recovery shocking of the seedlings. leaf area index (lai) leaf area index (lai) was significantly influenced by seedling age at 30, 45 and 60 days after transplanting (dat) (table 2). the highest lai was obtained at all sampling dates when 25-dold seedlings were transplanted and the lowest leaf area index was obtained at all sampling dates when 40-d-old seedlings were transplanted. lai gradually increased with the increase of time in all cases irrespective of the age of seedling whether it is young or old. this might be due to the internal mechanism of the plant to produce the maximum amount of food material to be accumulated in the grain by the utilization of solar radiation with the help of chlorophyll (hunt, 1978). lai was gradually decreased as the age of seedling increased at all sampling dates (table 2). but it was contradictory with the result found by hossain et al. (2011). storage duration had significant effect on lai at 1% level of probability at 15, 30, 45 and 60 dat (table 2). the highest lai (6.65) was obtained with 0-day of storage duration and the lowest (3.99) was obtained at all sampling dates with 3-days of storage duration at all sampling dates. lai was gradually increased up to 60 dat in all cases of storage durations. these findings are in line 49 effect of age and storage duration of seedling on growth and yield of wet season rice with hunt (1978). lai exhibited a trend of decrease with the increase in lai area index was significantly influenced by the interaction between the age and storage duration of uprooted seedlings at 15, 45 and 60 dat (table 2). at all sampling dates, the highest lai was obtained in 25-d-old seedlings with 0-day storage duration. lai was the lowest at 40-d-old seedlings with 3-day storage and the values were 0.51, 2.21 and 3.01 at 15, 45 and 60 dat, respectively (table 2). crop growth rate (cgr) crop growth rate (cgr) was significantly affected by age and storage duration of seedlings during the period of 15-30, 30-45 and 45-60 dat (figure 1 and 2). the highest crop growth rate was observed during all sampling periods when 25-d-old seedlings were transplanted and the lowest crop growth rate was obtained at all sampling dates when 40-d-old seedlings were transplanted. crop growth rate of all ages of seedlings attained peak within the period of 30-45 dat (figure 1). cgr changed with growth reached maximum at panicle emergence and decreased soon after (wilson and ellis, 1981; tanaka, 1983). similar results were also observed by hossain et al. (2011). the highest cgr was obtained during all sampling periods with 0 day storage duration and the lowest crop growth rate was obtained at all sampling dates with 3 days of storage duration. crop growth rate of all storage durations of uprooted seedlings attained peak within the period of 30-45 dat (figure 2). after attaining the peak, cgr gradually decreased soon after in all cases of storage durations (tanaka, 1983). interaction of age and storage duration of seedlings had no significant effect on cgr at 15-30 and 30-45 dat. however, it had significant effect on cgr at 45-60 dat. grain yield seedling age and storage duration of uprooted seedlings had significant effect on grain yield (figure 3 and 4). these findings are in conformity with karmakar and sarkar (2015) and hussain et al. (2012). grain yield in general declined along with increased seedling age and also storage duration (sarkar et al., 2011 and upadhyay et al., 2003). grain yield reduced by 13, 19 and 37% of 30, 35 and 40-d-old seedlings, respectively compared to 25-d-old seedlings. these findings are supported by karmakar and sarkar (2015) who reported that yield reduced by 22% in 35-d old seedlings compared to 14-d old seedlings. it might be due to transplanting of younger seedlings produced higher number of panicles per unit area and more grains per panicle while older seedlings could not compete with younger seedlings in this regards. moreover, higher sterility observed in older seedling than younger seedlings. these all together contributed to get higher yield in younger seedlings. similar yield reduction trend also found in case of seedling storage duration. grain yield reduced by 5, 14 and 31% of 1, 2 and 3-d storage of seedlings, respectively compared to 0-d storage. higher yield observed in 0-day storage duration compared 1, 2 and 3-day storage duration of seedlings. interaction of seedling age and storage duration of uprooted seedlings had no significant effect on grain yield except 35-d old seedlings with 2-d storage (figure 5). conclusion all the growth parameters of wet season rice exhibited a trend of increase with younger seedlings and without storage of seedlings. growth and development were gradually decreased with increased seedlings age from 25 to 40 days with storage durations ranging from 0 to 3 days. considering the possible delay in transporting seedlings to the flood affected area from 50 saha et al. the nearby districts, it may be concluded that 25-d-old seedlings may be kept stored up to 1 day after uprooting to get optimum growth and development that would be contributed for higher yield. table 1. effect of seedling age, storage and their interaction on shoot height and root length of wet season rice treat. shoot height (cm) root length (cm) days after transplanting days after transplanting 15 30 45 60 15 30 45 60 effect of seedling age a1 37.3 56.3 75.9 89.6 16.33 19.67 20.92 16.58 a2 37.2 54.8 73.8 88.3 16.17 19.08 20.50 14.67 a3 35.6 54.3 71.7 86.9 15.67 18.33 19.58 14.83 a4 35.1 50.4 67.7 86.7 14.25 17.50 17.75 14.50 lsd (0.05) 2.0 4.1 2.5 4.6 3.83 2.4 effect of storage duration of seedling d1 38.7 55.1 74.3 89.8 15.92 19.42 20.58 16.25 d2 36.8 54.7 72.3 88.1 15.58 19.00 20.08 14.92 d3 35.8 53.5 71.5 87.2 15.75 18.33 19.42 14.25 d4 34.3 52.7 71.1 86.4 15.17 17.83 18.67 14.17 lsd (0.05) 3.3 2.2 3.4 4.4 2.18 2.25 interaction effect of age and storage duration of seedling a1×d1 40.7 60.7 78.7 98.0 18.00 22.67 22.33 17.00 a1×d2 40.0 59.0 78.0 89.3 16.33 18.00 21.67 16.00 a1×d3 35.3 55.3 74.7 85.7 16.00 19.33 22.30 15.00 a1×d4 34.7 56.7 72.3 85.3 16.33 21.67 18.33 14.33 a2×d1 40.3 54.3 73.3 89.0 16.67 18.33 21.33 16.67 a2×d2 36.3 55.7 72.3 86.0 14.00 19.67 22.23 13.67 a2×d3 38.3 52.7 73.7 89.3 16.67 19.33 19.00 13.67 a2×d4 33.7 50.3 76.0 88.7 16.00 16.00 19.33 14.67 a3×d1 34.7 53.7 69.7 86.7 15.00 22.00 21.33 14.33 a3×d2 37.0 53.7 71.3 91.0 17.33 16.33 19.00 15.00 a3×d3 36.0 58.7 73.3 84.7 16.67 17.33 18.33 14.67 a3×d4 35.3 51.3 72.3 85.3 13.67 17.67 18.67 15.33 a4×d1 39.0 51.7 75.3 85.3 15.33 17.67 17.33 17.00 a4×d2 34.0 50.3 67.3 86.0 14.67 19.00 17.23 15.00 a4×d3 33.7 47.3 64.3 89.0 12.33 17.33 18.00 13.67 a4×d4 33.3 52.3 63.7 86.3 14.67 16.00 18.33 12.33 lsd0.05 6.6 7.3 6.8 8.9 ns ns 4.36 4.51 in a column, figures having common letter(s) do not differ significantly whereas the figures with dissimilar letters differ significantly as adjusted by dmrt a1 = 25, a2 = 30, a3 = 35 and a4 = 40-d old seedling. d1 = 0, d2 = 1, d3 = 2 and d4 = 3 days storage duration. 51 effect of age and storage duration of seedling on growth and yield of wet season rice table 2. effect of seedling age, storage and their interaction on tillers hill-1 and leaf area index of wet season rice treat. tillers hill-1 (no.) leaf area index days after transplanting days after transplanting 15 30 45 60 15 30 45 60 effect of seedling age a1 5.6 10.8 13.0 12.3 0.84 2.95 4.50 6.71 a2 5.5 10.5 11.8 11.2 0.82 2.51 4.11 6.10 a3 5.5 8.4 10.9 9.9 0.74 2.42 3.78 4.88 a4 4.7 9.6 10.2 9.7 0.73 1.88 3.57 4.50 lsd (0.05) 3.3 2.2 0.6 0.28 0.65 0.56 effect of storage duration of seedling d1 5.6 10.6 12.7 11.5 1.04 2.98 4.90 6.65 d2 5.4 10.2 11.8 10.9 0.68 2.60 4.10 6.33 d3 5.4 9.3 11.1 10.7 0.73 2.32 4.03 5.22 d4 4.9 9.3 10.4 10.3 0.67 1.86 2.92 3.99 lsd (0.05) 0.81 2.5 1.4 1.1 0.2 0.3 0.5 0.4 interaction effect of age and storage duration of seedling a1×d1 6.3 13.0 15.0 14.0 1.26 3.44 5.47 8.23 a1×d2 6.0 11.7 13.7 12.5 0.64 3.26 4.79 7.05 a1×d3 5.0 8.3 13.3 9.3 0.54 2.58 4.58 6.21 a1×d4 5.3 11.6 10.0 13.0 0.51 2.53 3.83 5.35 a2×d1 6.2 10.7 12.6 12.3 1.18 3.12 4.09 6.82 a2×d2 5.3 11.7 14.3 12.7 0.67 2.72 4.68 7.96 a2×d3 5.7 9.3 8.3 10.5 0.75 2.53 4.54 5.20 a2×d4 4.7 9.0 12.0 9.0 0.75 1.68 3.12 4.41 a3×d1 5.0 12.0 11.0 9.7 1.00 2.90 5.26 6.26 a3×d2 6.0 7.6 12.0 9.0 0.66 2.44 3.77 5.15 a3×d3 5.7 8.0 11.6 10.6 0.88 2.43 3.55 4.95 a3×d4 5.3 6.0 9.0 10.3 0.73 1.90 2.53 3.18 a4×d1 5.0 6.3 12.0 8.9 0.71 2.45 4.79 5.30 a4×d2 4.0 10.0 7.0 9.3 0.75 2.00 3.15 5.18 a4×d3 5.3 11.6 11.0 12.0 0.75 1.73 3.44 4.51 a4×d4 4.3 10.3 10.6 8.7 0.71 1.35 2.21 3.01 lsd (0.05) ns 4.93 2.8 2.2 0.28 ns 0.94 0.75 in a column, figures having common letter(s) do not differ significantly whereas the figures with dissimilar letters differ significantly as adjusted by dmrt a1 = 25, a2 = 30, a3 = 35 and a4 = 40-d old seedling. d1 = 0, d2 = 1, d3 = 2 and d4 = 3 days storage duration. 52 saha et al. 0 2 4 6 8 10 15-30 30-45 45-60 c g r × 1 0 2 (m g d -1 ) days after transplanting fig. 1. crop growth rate (cgr) of wet season rice as influenced by age of seedling at different days after transplanting. 0 2 4 6 8 10 15-30 30-45 45-60 c g r × 1 0 2 (m g d -1 ) days after transplanting fig. 2. crop growth rate (cgr) of wet season man rice as influenced by storage duration of seedling at different days after transplanting ● a1 = 25-d-old seedling ■ a2 = 30-d-old seedling ▲a3 = 35-d-old seedling * a4 = 40-d-old seedling ● d1 = 0 day storage duration ■ d2 = 1 day storage duration ▲d3 = 2 day storage duration * d4 = 3 day storage duration 53 effect of age and storage duration of seedling on growth and yield of wet season rice fig. 3. effect of seedling age on grain yield of var. brri dhan52 and yield reduction of 30, 35 and 40-d old seedling compared to 25-d old seedling. fig. 4. effect of storage duration of seedling on grain yield of var. brri dhan52 and yield reduction of 30, 35 and 40-d old seedling compared to 25-d old seedling. 54 saha et al. fig. 5. interaction effect of seedling age and storage duration on grain yield of var. brri dhan52 of 30, 35 and 40-d old seedling compared to 25-d old seedling. reference bali, a. s. and h. s. uppal. 1999. soil nitrate profile and root growth of basmati rice under varying transplanting dates and irrigation regimes. applied biol. res. 1(1): 25-28. bbs (bangladesh bureau of statistics) 2013. monthly statistical bulletin of bangladesh, bangladesh bureau of statistics, statistics division, min. plan., govt. of people's repub. of bangladesh, dhaka. pp. 71. brri (bangladesh rice research institute) 2011. annual report for 2010. bangladesh rice res. inst., joydebpur, gazipur. pp. 73-77. gomez, k. a and a. a. gomez. 1984. statistical procedure for agril. res. intl. rice res. inst., john wiley and sons. new york, chichester, brisbane, toronto, singapore. pp. 139-240. haque, d. e. 2002. effect of madagascar technique of younger seedling and wider spacing on growth and yield of boro rice. ms thesis, dept. agron., bangladesh agril. univ., mymensingh. pp. 28-71. hossain, m. a., m. a. r. sarkar and s. k. paul. 2011. growth of transplant aman rice as affected by row arrangement, age of tiller seedlings and number of tiller seedlings hill-1. tropical agril. res. and extension. 14 (4) (in press). hunt, r. 1978. plant growth analysis. study in biology no. 96. edward arnold, london. pp. 2730. 55 effect of age and storage duration of seedling on growth and yield of wet season rice hunt, r. 1978. the filled curve in plant growth studies. math and plant physiology (eds. rose, d.a. and edwards, d.a.c.). aca. press, london. pp. 283-298. huridal, s. s., k. prabhuyot and p. kaur. 1999. evaluation of agronomic practices for rice using computer simulation model. ceres-rice. oryza. 36(1): 63-65. islam, m. s. 1995. effect of variety and storing time of seedlings on the yield of boro rice. ms thesis, dept. agron., bangladesh agril. univ., mymensingh. pp. 6. karmakar b, m. a. r. sarkar. 2015. optimizing seedling age of promising rice genotypes in rainfed environment. journal of crop and weed, 11: 149-160. kaykobad, s. a. m. 2001. effect of storage conditions and storage durations of uprooted seedlings on the yield and yield contributing characters of transplant aman rice cv. binashail. ms thesis, dept. of agron., bangladesh agril. univ., mymensingh. pp. 36. paul, s. k., m. a. r. sarkar and m. ahmed. 2003. leaf production, leaf and culm dry matter yield of transplant aman rice as affected by row arrangement and tiller separation. asian j. plant sci. 5: 161-166. sarkar, m. a. r, s. k. paul, m. a. hossain 2011. effect of row arrangement, age of tiller seedlings and number of tiller seedlings hill-1 on performance of transplant aman rice. agril sci. j. 6 (2): 59-68. singh, r. s. and s. b. singh. 1998. response of rice (oryza sativa l.) to age of seedlings and level and time of application of nitrogen under irrigated condition. ind. j. agron. 43(4): 632635. tanaka, a. 1983. physiological aspects of productivity. in: potential productivity of yield crops under different environments. irri. los banos, phillippines. pp. 77-78. upadhyay v. v., r. mathew, s. k. vishwakarma, v. k. shukla. 2003. effect of number of seedlings per hill and age of seedlings on productivity and economics of transplanted rice. jnkvv. res. j. 37(1): 27-29. wilson, j. h. and ellis, r. d. 1981. supply of dry matter from stem and seed in rice grown under dry land conditions. intl. rice res. newsl. 6(1): 23-24. yoshida, s. 1981. physiological analysis of rice yield. in: "fundamentals of rice crop science". intl. rice res. inst., los banos, phillippines. pp. 269. bangladesh agron. j. 2023, 26(1): 28-31 performance of row spacing on the yield of sesame varieties mohammad ayub hossain khan1* and maminul islam2 1agronomy division, bangladesh agricultural research institute, gazipur, bangladesh 2department of agricultural extension, cox’s bazar, bangladesh *corresponding author, email: ayubagronomy@yahoo.com (received: 14 may 2023, accepted: 11 september 2023) keywords: sesamum indicum l., capsule, seed yield abstract the experiment was carried out during kharif-i season of 2020 in the experimental field of regional agricultural research station (rars), bangladesh agricultural research institute (bari), cumilla to evaluate the optimum plant spacing of sesame varieties. there were four plants spacing s1 (30 ××5 cm2), s2 (30×× 10 cm2), s3 (40 ××5 cm2) and s4 (40×× 10 cm2) and two sesame varieties of v1 (bari til 3) and v2 (bari til 4) were included in the experiment. the experiment was conducted using a split-plot design with three replications. the highest seed yield (1646 kg ha-1) was found from bari til 4 but the highest number of capsule plant1 and number of branches plant-1 were obtained from bari til-3. the maximum seed yield (1913 kg ha-1) was achieved in the interaction of s4v2 (40 ××10 cm2 and bari til 4) that was identical to s2v2 (30 x 10 cm2 and bari til 4). introduction sesame (sesamum indicum l.) commonly known as til in bengali, belongs to the sesamum genus of the pedaliaceae family. it is the second largest source of edible oil in bangladesh. the crop is grown in both summer and winter. it is grown mainly for seeds that contain 46% 64% oil and 20% protein (raja et al., 2007). sesame oil contains good quality polyunsaturated fatty acids viz., 47% oleic and 39% linoleic acid. we can get a very good quality edible and medicinal oil, from sesame and it can be conserved for a long time. til oil cake serves as a beneficial feed for various animals including poultry, fish, cattle, goats, and more. as sesame drought tolerant oilseed crop is grown successfully in the early summer in bangladesh under rain fed condition. the crop is cultivated either as a pure stand or as a mixed crop with aus rice, jute, groundnut, millets, and sugarcane. in bangladesh, sesame occupies a remarkable area under production and contributes second-ranked production after rapeseed and mustard. although at present about 21,347 hectares of land are under sesame cultivation with a production of 19795 metric tons (bbs, 2020) but land area and production under sesame cultivation is decreasing day by day. in our country the yield of sesame is very poor compared to india and other sesame growing countries of the world. to increase the productivity of sesame, various improved technologies are needed and among them, various agro-techniques, isolating location-specific varieties assumes greater significance. in particular, variety, sowing time, population density and or plant spacing, and fertilizer management are very important. plant spacing is one of the most important factors for getting higher yield. the optimum plant spacing depends on some factors including growing environment, planting system and cultivar used. recommended plant spacing for sesame is not enough for normal growth and development for recently released high yielding sesame varieties. keeping this point in mind, this experiment was undertaken to evaluate the performance of sesame varieties under different plant spacing for getting higher yield. effect of row spacing on sesame 29 materials and methods the experiment was conducted at the research field of rars, bari, cumilla, bangladesh during the kharif i season, 2020. the soil of the experimental plot was sandy loam. the experiment was conducted using a splitplot design with three replications. the unit plot size was 3.6 m × 2.0 m. four spacing were arranged in main -plot and two varieties in subplots. the spacing of the experiment were; s1 = 30 × 5 cm2, s2 = 30 × 10 cm2, s3 =40 × 5 cm2 and s4 =40 × 10 cm2 and the varieties were v1= bari til 3 and v2 = bari til 4. the seeds were sown on 17 march, 2020. the seed rates were used @ 8 kg ha−1 and after 25 days after emergence the spacing were maintained according to the treatment. seeds were placed 2 to 3 cm depth in rows and seeds were covered with loose soil properly. fertilizers were applied @ 50, 30, 25,20,1.8 and 1.8 of n-p-k-s-zn & b kg ha−1 respectively. half urea and all other fertilizers were applied as basal dose; remaining urea was top dressed at 25 days after sowing (das). thinning and weeding were done at 20 and 40 days after emergence. irrigation was given two times at 30 days after sowing (before flowering) and 60 das. ripcord was given three times @ 3g l−1 of water for controlling the infestation of sesame hairy caterpillar. bavistin was sprayed @ 2 g l−1 of water for controlling the stem rot disease. at maturity stage, before harvesting ten randomly selected plants were uprooted to collect data on plants m2, plant height, branches plant−1, capsules plant−1, seeds capsule−1, and 1000-seed weight and yield m2. data were analyzed statistically and treatments means were compared by least significant difference (lsd) test. results and discussion effect of spacing the maximum number of branches plant-1 (4.30) was found in treatment s4 (40 × 10 cm) which was identical with s2 (30 × 10 cm) and s3 (40 × ×5 cm2) and the lowest (3.30) in s1 (30 ××5 cm2). the maximum capsules plant-1 (65.20) was observed in s4 (40××10 cm2) which was identical with s3 (40 ××5 cm2) and s2 (30 × 10 cm2) and the lowest in s1 (30 × 5 cm2). the highest seeds capsule-1 (82.2) was found in s2 (30 × 10 cm2) and the lowest (72.3) in s1 (30 × 5 cm2). the maximum 1000 -seed weight (2.80 g) was achieved in s1 (30×5 cm2) followed by s3 (40×5 cm2) and the lowest (2.60g) in s2 (30 × 10 cm). the maximum seed yield (1817 kg ha-1) was obtained in s4 (40 ×10 cm2) that was statistically identical with s2 (30 × 10 cm2) and the lowest yield (1234 kg ha-1) in s1 (30 × 5 cm2). enhanced exploitation of resources viz., solar radiation, nutrients, and water etc. may have favored 40 cm×××10 cm spacing in obtaining the maximum grain yield. the finding was in agreement with shinde et al., 2011 and yadav et al., 2007. table1. effect of spacing on yield and yield attributes of sesame during kharif–i, 2020 in rars, bari, cumilla treatment plant height (cm) branches plant−1 (no.) capsules plant−1 (no.) seeds capsule−1 (no.) 1000-seed weight (g) seed yield (kg ha−1) s1(30×5 cm2) 123.50 3.30 51.20 72.30 2.80 1234 s2(30×10 cm2) 120.20 4.10 58.50 82.20 2.60 1735 s3(40×5 cm2) 123.80 3.60 59.30 75.70 2.80 1457 s4(40×10 cm2) 124.70 4.30 65.20 78.20 2.70 1817 lsd(0.05) ns 0.97 12.83 ns ns 180.9 cv (%) 3.50 12.68 10.96 9.45 8.18 5.80 30 khan & islam effect of variety the highest plant height (124.20 cm), seeds capsule−1 (78.70) and seed yield (1646 kg ha−1) were achieved in var. bari til 4 and the lowest in bari til 3. the highest branches plant−1 (4.0), capsule plant (61.1) and 1000seed weight (2.80g) was obtained in bari til 3 and the lowest in bari til 4. similar results on 1000seed weight was also found by kokilavani et al. 2007, and riaz et al. 2002 indicated that the number of capsules plant-1 differed significantly by different varieties. chongdar et al. 2015 also observed variation in the number of seeds capsule−1 due to different varietal performance. suryabala et al. (2008) opined that different sesamum cultivars showed a significant variation in seed yield. table 2. effect of varieties on yield and yield attributes of sesame during kharif-i, 2020 in rars, bari, cumilla treatment plant height (cm) branches plant−1 (no.) capsules plant−1 (no.) seeds capsule−1 (no.) 1000-seed weight (g) seed yield (kg ha−1) variety v1 (bari til 3) 121.9 4.00 61.10 75.50 2.80 1475 v2 (bari til 4) 124.2 3.70 56.00 78.70 2.70 1646 level of significant ns * * ns ns * interaction effect between spacing and varieties of sesame table-3 showed that different spacing and varieties had significant effect on branches plant-1, capsule plant-1 and seed yield (kg ha−1). table 3. interaction effect of spacing and variety on yield and yield attributes of sesame varieties during kharif-i 2020 in rars, bari, cumilla treatment (spacing× variety) plant height (cm) branches plant−1 (no.) capsules plant−1 (no.) seed capsule−1 (no.) 1000-seed weight (g) seed yield (kg ha−1) s1v1 121.70 3.70 55.30 71.00 2.70 1257 s1v2 125.30 3.00 47.00 73.70 2.90 1211 s2v1 120.30 4.30 61.00 79.70 2.60 1614 s2v2 120.00 3.90 56.00 84.70 2.60 1856 s3v1 122.00 4.00 65.00 75.70 3.00 1309 s3v2 125.70 3.30 53.70 75.70 2.80 1605 s4v1 123.70 4.10 63.00 75.70 2.80 1720 s4v2 125.70 4.50 67.30 80.70 2.70 1913 cv (%) 4.42 8.34 4.83 8.31 7.24 5.04 lsd(0.05) ns 0.60 5.325 ns ns 148 s1=30×5 cm, s2=30×10 cm, s3=40×5 cm, s4=40×10 cm; v1= bari til 3, v2= bari til 4 the maximum branches plant-1 (4.50) was observed in the interaction of s4v2 (40 × 10 cm2 spacing and variety bari til 4) which was identical to the interaction of s2v1 (30 ××10 cm2 ×bari til 3), s4v1 (40 ××10 cm2 × bari til 3), s3v1 (40 ××5 cm2 × bari til 3), s2v2 (30 ××10 cm ×bari til 4) and the lowest branches plant−1 (3.0) of s1v2 (30 ××5 cm and bari til 4). the maximum number of capsule plant−1 (67.3) was obtained in s4v2 (40 ××10 cm2 and variety bari til 4) which was statistically identical to s3v1 (40 ××5 cm and bari til 3) and s4v1 (40 ××10 cm2 and bari til 3) and the lowest capsule plant−1 (47.0) of s1v2 (30×××5 cm and bari til 4). the maximum seed yield (1913 kg ha-1) was achieved in the interaction of s4v2 (40 ××10 cm and bari til 4) that was identical to s2v2 (30 ××10 cm and bari til 4) and the lowest yield (1211 kg ha−1) in the interaction of s1v2 (30×××5 cm and bari til 4). the finding of ozturk (2012) showed effect of row spacing on sesame 31 that the highest seed yield was obtained from the narrow row spacing (30 cm) whereas the lowest seed yield from widest row spacing (70 cm). the highest plant height (125.7 cm) was observed of s4v2 (40×××10 cm and bari til 4) and s3v2 (40×5 cm2 and bari til 4) and the lowest plant height (120.0 cm) of s2v2 (30×××10 cm2 and bari til 4). the highest seeds capsule-1 (84.7) was obtained of s2v2 (30 × 10 cm and bari til 4) and the lowest (71.0) was obtained of s1v1 (30 ××5 cm2 and bari til 3). the highest 1000seed weight (3.00 g) was achieved of s3v1 (40 × 5 cm2 and bari til 3) and the lowest (2.60 g) in s2v1 (30 × 10 cm2 and bari til 3) followed by s2v2 (30×××10 cm and bari til 4). conclusion from the study, it may be concluded that 40 ××10 cm2 or 30×××10 cm2 would be the optimum spacing for sesame var. bari til 4 or bari til 3. these results indicate that 40 × 10 cm2 and 30 × 10 cm2 could be the optimum row spacing of sesame under the agro-ecological conditions of the experimental location. references bbs (bangladesh bureau of statistics). 2020. statistical pocketbook of bangladesh. bangladesh bureau of statistics. statistics division, ministry of planning. government of the people’s republic of bangladesh. chongdar, s., b. chhetri, s. mahato and a. saha. 2015. production potentials and economic feasibility of improved sesame (sesamum indicum l.) cultivars under varying dates of sowing in prevailing agroclimatic condition of north bengal. int. j. agric. sci. 7(2): 434-439. kokilavani, s., r. jagannathan and s.k. natarajan. 2007. manual terminal clipping on yield and nutrient uptake of sesame varieties. res. j. agric. biol. sci. 6(3): 987-999. oztürk, o. and o. saman. 2012. effects of different plant densities on the yield and quality of second crop sesame. int. j. agric. biosyst. engin. 6(9): 644-649. raja, a., k.o. hattab, l. gurusamy and s. suganya. 2007. sulphur levels on nutrient uptake and yield of sesame varieties and nutrient availability. int. j. soil sci. 2(4): 278-285. riaz, a., m. tariq, s.m. farrukh and a. shamim. 2002. comparative performance of two sesamum (sesamum indicum l.) varieties under different row spacings. asian j. plant sci. 1(5): 546-547. shinde, s.d., b.s. raskar and b.d. tamboli. 2011. effect of spacing and sulphur levels on productivity of sesame (sesamum indicum l.) under summer condition. j. maharastra agric. univ. 36(1): 28-31. suryabala, y., a.b. abidi, r.p. singh and s. anju. 2008. response of sulphur nutrition on nutritional characteristics of oil and cake of sesame (sesamum indicum l.) varieties. j. oilseeds res. 25(1): 3840. yadav, r.a., m. akhilesh and d. singh. 2007. response of sesame cultivars under various plant spacing and seed rates. plant arch. 7(1): 287-288. bangladesh agron. j. 2019, 22 (1): 115-120 intercropping of cabbage with maize m.m. khanum1*, m.m. bazzaz2, b. ahmed3, m.s. huda4 and m.a. hossain5 1scientific officer, agricultural research station, bari, rajbari, dinajpur-5200 2senior scientific officer, bangladesh wheat and maize research institute, nasipur, dinajpur-5200 3scientific officer, plant physiology division, station, bari, gazipur-1701 4,5senior scientific officer, agricultural research station, bari, rajbari, dinajpur-5200 corresponding e-mail: mahbuba.bari27@gmail.com (received: 19 september 2019, accepted: 27 november 2019) keyword: intercropping, maize, cabbage, cereal, yield, cost-benefit abstract the experiment was carried out at the research field of agricultural research station, rajbari, dinajpur (latitude: 25.63544, longitude: 88.65144) during rabi season of 2016-2017 and 2017-18 under aez-1 to find out the suitable crop combination for higher productivity and economic return. five different treatments were employed in the study viz. t1= sole maize (60cm x×20cm), t2= maize planting (75cm×x 25cm) + 1 row cabbage (50cm×50cm) t3= maize paired row (150cm/37.5cm x 25cm) + 2 rows cabbage (50cm x×50cm) t4=maize planting (60cm x×20cm )+1 row cabbage (60cm x×50cm), t5= maize paired row (120cm/30cm× x 20cm) + 2 rows cabbage (60cm x 50cm) were evaluated. maize grain yield in intercropped combination varied from 6.60-9.23 t ha-1. but the highest maize yield was recorded in maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) followed by that in maize paired row (150/37.5cm × 25cm) +2 rows cabbage (50cm x×50cm), while the highest cabbage yield was recorded in maize planting (60cm x 20cm) + 1 row cabbage(60cm x 50cm) between maize. the highest maize equivalent yield was also obtained in maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) followed by that in maize paired row (150/37.5cm x 25cm) + 2 rows cabbage (50cm x 50cm). the highest gross return, gross margin and bcr were obtained in maize planting (60cm × 20cm) + 1 row cabbage (60cm x 50cm) followed by that in maize paired row (150/37.5cm x 25cm) +2 rows cabbage(50cm x 50cm) and the lowest in sole sowing of maize. the overall results indicated that among the intercrop combinations maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) and maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm) were found suitable for total productivity and economic return of the system. introduction intercropping may be defined as the cultivation of two or more crops at the same time in the same field (ouma and jeruto, 2010). intercropping offers a possible solution to raise productivity through temporal intensification in a country like bangladesh where the possibility of bringing more land under cultivation is limited. yield advantages through intercropping have been reported by many workers (willey, 1979). the advantages is often attributed to the fact that different crops complement each other and make better use of resources when grown together rather than separately (ahmed et al., 2018). besides, intercropping also acts as insurance for resource poor farmers if one crop fails, they get some yield of another crop (islam et al., 2014). maize (zea mays) is a versatile photo insensitive crop which can give high yield relatively in a shorter period of time due to its unique photosynthetic mechanism as c4 plant (hatch about:blank 120 khanum et al. and slack, 1998). maize is the third important cereal crop in bangladesh (bbs, 2015). the area coverage under maize in dinajpur is expanding rapidly instead of wheat. due to development of some potential hybrid maize and its availability in this region, farmers tend to shift their cultivation with maize crop in rabi season (shaheenuzzaman et al., 2015). in addition to that, favorable agro-climatic conditions have made this crop suitable for greater adoption in winter season in dinajpur region as well as in the country. being row and spaced crop, some short duration vegetables may have access to grow with maize as intercrop for extra quick cash generation without hampering maize yield. innovations in maizelegume intercropping allow farmers to grow a wide range of food legumes as understory intercrops with maize. maize can be planted at its recommended population, but every other row is shifted to provide a wider alternate inter row to the legume or strip-cropped by lowering maize population but maintaining similar yields (ahmed et al., 2008). growing of short duration vegetables specially cabbage as intercrop with maize in between row may offer considerable yield advantage over sole cropping due to efficient utilization of growth resources (talukder et al., 2016). cabbage (brassica oleracea l.var. capitata f.), is an important cole crop, belonging to family cruciferae, is rich in phyto nutrients and antioxidants. mixed or intercropping can increase total productivity of land through maximum utilization of natural resources (thayamini et al., 2010). higher total productivity per unit area in intercropping is achieved over sole cropping (boras et al., 2006). intercropping practices lead to more monetary return and better utilization of land and inputs (quayyum et al., 1985). regarding this views, an attempt was undertaken to get maximum benefit from intercropping by optimizing plant population of maize and cabbage. materials and methods the experiment was conducted in the research field of agricultural research station, rajbari, dinajpur (latitude: 25.63544, longitude: 88.65144) during rabi season of 2016-2017 and 2017-18. the experiment was laid out in randomized complete block (rcb) design with three replications. the unit plot size was 6m x 4m. five different treatments were employed in the study viz. t1= sole maize (60cm x×20cm), t2= maize planting (75cm x 25cm) + 1 row cabbage (50cm x 50cm), t3= maize paired row (150cm/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm), t4=maize planting (60cm×20cm) +1 row cabbage (60cm x 50cm), t5=maize paired row (120cm/30cm x 20cm) +2 rows cabbage (60cm x 50cm). the land of the experimental plot was prepared with a power tiller by ploughing and cross ploughing followed by laddering and the soil was brought into good tilth. fertilizers were applied @ 260-72-148-48-4-2 kg ha-1n-p-k-s-zn-b in the form of urea-tsp-mop-gypsum-znso4-boric acid for both the sole maize and intercrop combinations. one third of urea and full amount of other fertilizers were applied at final land preparation. remaining urea was applied at 30 and 60 das in two equal splits. maize (bari hybrid bhutta-9) was sown on november 02-04 during the conducting years and cabbage (bari badhacopy-1) was sown on november 12-14 during the consecutive years. two irrigations were provided after top dressing of urea. earthing up and other intercultural operations were done when required. other plant protection measures were taken when required. cabbage was harvested on january 10-12 and the maize on april 1013 respectively during the consecutive years. yield contributing characters of cabbage and maize were measured from ten randomly selected plants of the sampling area of each treatment avoiding border plants. maize grain yield and cabbage yield were measured from the whole plot and then calculated per hectare basis maintaining standard moisture content. the relative yield was intercropping of cabbage with maize 119 obtained by dividing the intercrop yield of a crop with the respective sole crop yield of that crop using the formula (dewit and vander bergh, 1965). the relative yield of a crop = yield of component crops / yield of sole crop maize equivalent yield was computed by converting yield of intercrops on the basis of prevailing market price of individual crop following the formula of bandyopadhyay (1984) as given below: maize equivalent yield = yim + (yic x pc) / pm where, yim = yield of intercrop maize, yic = yield of intercrop cabbage, pm = market price of maize and pc = market price of cabbage. collected data were statistically analyzed by using mstat software packages and mean differences for each character were compared by least significant difference (lsd) test (gomez and gomez, 1984). results and discussion effect on yield and yield components of maize yield and yield contributing characters of intercropped maize were statistically significant (table 1). the highest plant height (273.13 cm) was recorded from sole maize and the lowest plant height (244.28cm)was obtained from maize paired row (120cm/30cm20cm) + 2 rows cabbage (60cm50cm) intercropping combination. the highest number of grains cob-1 (579.06) was recorded from sole maize plot and the lowest number of grains cob-1 (453.27) was found in maize paired row (120cm/30cm20cm) +2 rows cabbage (60cm50cm) intercropping combination. the same trend was observed in case of 1000grain weight and it was ranged from 236.73285.53 g in different treatments. the highest 1000 grain weight (285.53 g) was recorded from sole maize and the lowest 1000 grain weight (236.73) was obtained from maize paired row (120cm/30cm20cm) + 2 rows cabbage (60cm50cm) intercropping combination. the highest grain yield (9.11 t ha-1) was recorded from sole maize, which could be due to higher no. of grains cob-1 and 1000grain weight. the grain yield of maize in intercropped combination varied from 6.60-9.23 t ha-1. the yield data indicated that due crop competition in intercropping yield loss of maize was observed. effect of intercrops the intercrop yield of cabbage was influenced significantly by different intercropping combinations (table 2). the highest cabbage yield (50.04 t ha-1) was recorded from maize planting (60cm20cm) + 1 row cabbage (60cm50cm) intercropping combination followed by maize paired row (150cm/37.5cm  25cm) + 2 rows cabbage (50cm  50cm) combination (46.97 t ha-1). the lowest yield was obtained from maize planting (75cm25cm) +1 row cabbage (50cm50cm) intercropping combination (41.41t ha-1). maize equivalent yield maize as wider spaced plant offers some component crops to grow together without economic loss sacrificing small maize yield with greater total production in respect of land and time. this practice offered considerable yield advantages and higher economic return over sole cropping because of its efficient utilization of growth resources (faruque et al., 1996). all the intercropped combinations showed higher maize equivalent yield than sole maize in all cases. among the treatments, the highest maize equivalent yield (25.50 t ha-1) was obtained from maize planting (60cm x 20cm)+ 1 row cabbage (60cm x 50cm) followed by that of maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm50cm) intercrop combination in the both years (table 2). the lowest maize equivalent 120 khanum et al. yield (20.40 t ha-1) was obtained from maize paired row (120cm/30cm x 20cm) + 2 rows cabbage (60cm x 50cm) intercrop combination. cost and return analysis the cost and return analysis of sole and intercropping of maize and cabbage are presented in table 3. higher gross return was obtained from all intercrop combinations than sole crop. the result revealed that the highest gross return (tk. 382500 ha-1) and gross margin (tk. 298270 ha-1) were obtained in maize planting (60cm × 20cm) + 1 row cabbage (60cm50cm), followed by maize paired row (150/37.5cm × 25cm) +2 rows cabbage (50cm50cm). the lowest gross return and gross margin were obtained from sole maize. the highest benefit cost ratio (4.54) was also obtained from maize planting (60cm × 20cm) + 1 row cabbage (60cm50cm) followed by that of maize paired row (150/30cm × 25cm) +2 rows cabbage (50cm50cm) and the lowest in sole maize (2.55). table 1. yield and yield contributing characters of maize and yield of cabbage underinter cropping situation at ars, rajbari, dinajpur (pooled data of 2 years) treatments plant height (cm) grains cob -1 (no.) 1000-grain wt.(g) yield (t ha-1) maize cabbage t1 273.15 558.13 285.53 9.23 t2 269.40 579.06 266.80 6.69 46.32 t3 251.04 532.33 265.60 7.82 46.97 t4 270.43 570.06 270.80 8.82 50.04 t5 244.28 453.27 236.73 6.60 41.41 cv (%) 3.24 5.13 3.25 3.56 5.44 lsd(0.05) 13.59 52.04 13.79 13.17 5.04 t1= sole maize (60cm20cm), t2= maize planting (75cm25cm) +1 row cabbage (50cm50cm ), t3= maize paired row (150cm/37.5cm  25cm) + 2 rows cabbage (50cm  50cm), t4= maize planting (60cm20cm)+ 1 row cabbage (60cm50cm), t5= maize paired row (120cm/30cm20cm) + 2 rows cabbage (60cm50cm). table 2. maize grain yield, cabbage yield, maize relative and equivalent yield influenced by intercropping with cabbage at ars, rajbari, dinajpur treatments maize grain yield (t ha-1) cabbage yield (t ha-1) relative yield of maize (t ha-1) maize equivalent yield (t ha-1) t1 9.23 9.23 t2 6.69 46.32 0.72 22.13 t3 7.82 46.97 0.85 23.48 t4 8.82 50.04 0.95 25.5 t5 6.60 41.41 0.71 20.40 t1= sole maize (60cm x 20cm), t2= maize planting (75cm x 25cm) +1 row cabbage (50cm x 50cm ), t3= maize paired row (150cm/37.5cm x 25cm) + 2 rows cabbage (50cm x 50cm), t4= maize planting (60cm x 20cm)+ 1 row cabbage (60cm x 50cm), t5= maize paired row (120cm/30cm x 20cm) + 2 rows cabbage (60cm x 50cm). table 3. cost and return analysis of maize and cabbage under sole and intercropping situations (average of two years) intercropping of cabbage with maize 119 treatments gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 138450 54230 84220 2.55 t2 331950 84230 247720 3.94 t3 352150 85457 266693 4.12 t4 382500 84230 298270 4.54 t5 306050 87251 218799 3.50 market price: maize 15 tk. kg-1, cabbage 5 tk. kg-1 conclusion the results revealed that the highest yield of maize was obtained in sole cropping of component crops. under intercropping, the highest maize yield was recorded in maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) followed by that of maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm), while the highest cabbage yield was recorded in maize planting (60cm × 20cm) + 1 row cabbage (60cm x 50cm) between maize. the highest maize equivalent yield was also obtained in maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) followed by that of maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm). the highest gross return, gross margin and bcr were obtained in maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) followed by that of maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm) and the lowest in sole sowing of maize. the overall results indicated that among the intercrop combinations maize planting (60cm x 20cm) + 1 row cabbage (60cm x 50cm) and maize paired row (150/37.5cm x 25cm) +2 rows cabbage (50cm x 50cm) were found suitable for total productivity and economic return of the system. references ahmed, b., d. shabnam, s. shabnam, m.a. hossain and m.m. islam. 2018. intercropping grasspea with chilli at varying plant population. int. j. app. res. 4 (1): 58-61. ahmed, h., h. herren, z. r. khan, j. a. pickett and c. m. woodcock. 2008. integrated pest management: the push-pull approach for controlling insect pests and weeds of cereals and its potential for other agricultural systems including animal husbandry. philos trans r soclond b biol sci. 363(1491): 611-621. bbs (bangladesh bureau of statistics). 2015. statistical pocket book of bangladesh. statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh. pp.91–93. boras, m., n. roukia and r. babilie. 2006. the effect of corn intercropping on autumn potato in terms of productivity and land equivalent ratio. tishreen univ. j. studies & scientific researchbiol. sci. series.28(1). bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph.d. dissertation, indian agril. res. inst., new delhi. baidoo, p.k., m.b. mochiah and k. apusiga. 2012. onion as a pest control intercrop in organic cabbage (brassica oleracea) production system in ghana. sus. agric. res. 1(1): 36-41. 120 khanum et al. dewit, c. t. and j. p. vander bergh. 1965. competition between herbage plants. neth. j. agri. sci. 13: 212-221. faruque.a., a. hashem and a. jahan. 1996. productivity and profitability of potato intercropped with wheat. bangladesh j. bot. 25(1): 1-4. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons, new york. pp.97-129. hatch, m.d. and c.r. slack. 1998. c4 photosynthesis: discovery, resolution, recognition and significance. discoveries in plant biology, world scientific publishing, singapore. 1: 175–196. islam, h.m.s., r.u. choudhury, b. ahmed, s. shabnam and m.m. rahman. 2014. adoption of mixed cropping in rabi season by the farmers of madaripur sadarthana under madaripur district. intl. j. buss. soc. sci. res. 1(3): 168171. ouma, g. and p. jerito. 2010. sustainable horticultural crop production through intercropping: the case of fruits and vegetable crops: a review. agric. bio. j. north america. 1(5): 1098-1105. quayyum, m.a., m.e. akanda and t. islam. 1985. effect of intercropping maize with groundnut at varying levels of plant population and nitrogen levels, bangladesh j. agric. 10(3): 1-6. shahenuzzaman, m., r.r. saha, b. ahmed, j. rahman and m. salim. 2015. green cob and fodder yield of sweet corn as influenced by sowing time in the hilly region. bangladesh j. agril. res. 40(1): 61-69. talukder, a.h.m.m.r., b. ahmed, l. nahar, k.m.f. hossain, j. rahman and s.k. paul. 2016. enhancement of farm productivity through intercropping of vegetables, pulse and oilseed crops with wheat at jamuna char area of islampur in jamalpur district. int. j. appl. res. 2(2): 71-76. thayamini, h., seran and i. brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135–145. willey, r.w. 1979. intercropping its importance and research needs. part. 1. competition and yield advantages. field crops abst. 32(1): 1-10. microsoft word 3 bangladesh agron. j. 2017, 20(2): 17-26 effect of spacing and seedling per hill on the effect of spacing and seedling per hill on the effect of spacing and seedling per hill on the effect of spacing and seedling per hill on the performance of aus rice performance of aus rice performance of aus rice performance of aus rice var. var. var. var. brri dhan48brri dhan48brri dhan48brri dhan48 t. a. ninadt. a. ninadt. a. ninadt. a. ninad1111, m. m. bahadur, m. m. bahadur, m. m. bahadur, m. m. bahadur2222, m. a. hasan, m. a. hasan, m. a. hasan, m. a. hasan2222, m. m. alam, m. m. alam, m. m. alam, m. m. alam3333 and m. s. ranaand m. s. ranaand m. s. ranaand m. s. rana1111 1m. s. student, dept. of crop physiology and ecology, hajee mohammad danesh sci. and tech. university, dinajpur 2professor, dept. of crop physiology and ecology, hajee mohammad danesh sci. and tech. university, dinajpur 3lecturer, dept. of agronomy, shahid akber ali science and technology college, thakurgaon. (received:received:received:received: 20 april 2017, accepted:accepted:accepted:accepted: 7 december 2017)))) key words: key words: key words: key words: spacing, no. of seedling, yield, var. brri dhan48, aus rice abstractabstractabstractabstract an experiment was conducted at the research field and laboratory in the department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur, during the period of april to august, 2016 to study the effect of spacing and number of seedlings hill-1 on the yield of aus rice var. brri dhan48. four spacing’s viz. 20 cm × 10 cm, 20 cm × 15cm, 20cm × 20 cm and 20 cm × 25cm and three number of seedlings hill-1 viz. 1, 2 and 4 were included in the study. results indicated that the highest number of total tillers hill-1 (22.86), number of effective tillers hill-1 (21.24), number of grains panicle-1 (128.79) and 1000-grain weight (23.30g) were found with 20cm × 25cm spacing. the highest plant height (104.27 cm), number of leaves plant-1 (35.80), grain yield (3.06 tha-1), straw yield (3.37 tha-1) and harvest index were obtained from 20 cm × 10 cm spacing. the highest grain yield of 2.98 t ha-1 was obtained from 4 seedlings hill-1, while the lowest 2.47 t ha-1 from 1 seedlings hill-1. the highest grain yield of 3.40 tha-1 was obtained from 20 cm × 10 cm spacing with 4 seedlings hill-1 while the lowest grain yield of 2.21 tha-1 from the wider spacing. results of the present study revealed that 20 cm x 10 cm spacing with 4 seedlings hill-1 combination was found to be the best for obtaining maximum grain yield of aus rice var. brri dhan48. introductionintroductionintroductionintroduction rice is the most extensively cultivated staple food crop for the people of bangladesh. it plays a vital role in bangladesh agriculture as it covers 74 per cent of total cultivable area (ais, 2001). the total production under rice cultivation in bangladesh about 19.1 million tons from boro, 13.02 million tons from aman and 2.6 million tons from aus rice in 2014-15 (bbs, 2015). rice is grown in three distinct season’s viz. aus, aman and boro among which aus rice covers only 12.27% of the rice growing area. the average yield of rice in aus is only 1.45 (bbs, 2001). so, among these three seasons, rice yield is the lowest in aus season as compared to the other growing seasons and therefore, efforts should be made to increase the yield of aus rice. optimum plant density ensures proper growth of the aerial and underground parts of the plant through efficient utilization of solar radiation, nutrients, land as well as air spaces and water (miah et al., 1990). regardless of plant spacing within and among rows, plant density must be such that the crop develops a canopy able to intercept more than 95% of the incoming solar radiation during reproductive growth. baloch et al. (2002) reported that appropriate plant density of a cultivar is necessary for obtaining higher yield and quality of rice. 18 ninad et al. number of seedlings hill-1 is an important factor for successful rice production which affects plant population unit-1 area, availability of sunlight and nutrients, photosynthesis and respiration, which ultimately influence the yield of crop (chowdhury et al., 1993). excess number of seedlings hill-1 may produce higher number of tillers hill-1 resulting in mutual shading and lodging and thus favouring the production of higher grain and straw yield, while less number of seedlings hill-1 may cause reduction of total number of panicles in per unit area which may be associated with poor yield. therefore, an experiment was conducted to find out the effect of spacing and number of seedlings hill-1 on the yield of aus rice var. brri dhan48. materials materials materials materials and mand mand mand methodsethodsethodsethods the experiment was conducted at the research farm and laboratory of crop physiology and ecology department, hajee mohammad danesh science and technology university (hstu), dinajpur during april to august, 2016 to study the effect of spacing and number of seedlings hill-1 on the yield of aus rice var. brri dhan48. the experimental field was a medium high land belonging to the non-calcareous dark gray floodplain soil under the agro-ecological zone (aez-1) of old himalayan piedmont plain (fao, 2005). treatments include four spacing’s viz. 20 cm × 10 cm, 20 cm × 15 cm, 20 cm × 20 cm and 20 cm × 25 cm and three numbers of seedlings hill-1 viz. 1, 2 and 4 were. the experiment was carried out in a randomized complete block design with three replications. the unit plot size was 3.0 m × 2.0 m. brri dhan48 is a high yielding variety of aus rice developed by brri was used as planting material. the experimental land was prepared through ploughing and cross ploughing and fertilized with urea, triple super phosphate (tsp) muriate of potash (mop), gypsum and zinc sulphate at the rate of 180, 100, 60, 60 and 10 kg ha-1, respectively. twenty five days old seedlings were transplanted on 5th may, 2016 with 20 cm spacing between lines and 10, 15, 20 and 25 cm spacing between hills in respective treatment intercultural operations were done for maintaining the normal growth and development of the crop. the crop was harvested at full maturity and five hills were randomly selected from each unit plot for recording of necessary data. the collected data was analyzed by using the “analysis of variance” (anova) technique with the help of a computer package (mstat-c) program (gomez and gomez, 1984). results and results and results and results and ddddiscussioniscussioniscussioniscussion plant height (cm): plant height (cm): plant height (cm): plant height (cm): the effect of row spacing and number of seedling hill-1 on plant height at different days after transplanting (dat) was statistically significant (table. 1). results showed that plant height increased with decreasing row spacing. the tallest plant was recorded at s1 (20 cm × 10 cm) spacing while shortest plant was recorded at s4 (20 cm × 25 cm) spacing. the taller plant in densely populated plants might have resulted due to competition for sunlight than those of wider spacing as reported by abbas et al. (1994) and akita et al. (1992). result showed that at 35, 55, 75 dat and at harvest n3 (4 seedlings hill-1) showed the longest plant while n1 (1 seedling hill-1) showed shortest plant. the result was similar with the findings of shrirame et al. (2000) and shah et al. (1991). results indicated that the longest plant was found in 20 cm × 10 cm spacing with 4 seedlings hill-1 (s1n3). number of leaves hillnumber of leaves hillnumber of leaves hillnumber of leaves hill----1111:::: significant variations were observed in number of leaves hill-1 at 55 and 75 dat as influenced due to row spacing (table 1). results showed that s1 treatment was 19 effect of spacing and seedling per hill on the performance evident for the highest number of leaves hill-1 and the lowest in s4. in case of number of seedling hill-1 4 seedling hill-1 showed highest number of leaves per hill while lowest number of leaves hill-1 from 1 seedling hill-1 which was supported by shrirame et al. (2000). interaction effect indicated that the highest number of leaves hill-1 was found s1n3 and the lowest number in s4n1 at 55 and 75 dat. number of total tillers hillnumber of total tillers hillnumber of total tillers hillnumber of total tillers hill----1111:::: the highest number of total tillers hill-1 was recorded at s4 (20 cm × 25 cm) and the lowest at s1 (20 cm × 10 cm) spacing. reduction in total tillers hill-1 in closer spacing might be due to increased number of plants per unit area. this increased number of plants per unit area exerted competition among plants for nutrients and light that caused a reduction in tiller number. similar results were also reported by baloch et al. (2002) in rice. results showed that (4 seedling hill-1 showed the highest number of total tillers hill-1 (23.47). the results are in conformity with karmakar et al. (2002), shrirame et al. (2000) and bina (1987). in case of interaction the highest number of total tillers hill-1 was found in s4n3 and the lowest one in s1n1. number of effective tillers hillnumber of effective tillers hillnumber of effective tillers hillnumber of effective tillers hill----1111:::: the effect of row spacing, seedling number hill-1 and the interaction was statistically significant (table 2). the highest number of effective tillers hill-1 was recorded at 20 cm x 25 cm spacing and the lowest 20 cm x 10 cm spacing increase in effective tillers hill-1 in wider spacing might be due to increased number of plants per unit area. similar results were also reported by baloch et al. (2002) in rice. the highest number of effective tillers hill-1 was found from 4 seedlings hill-1 and the lowest number with 1 seedlings hill-1 which was supported by islam (1980). number of nonnumber of nonnumber of nonnumber of non----effective tillers hilleffective tillers hilleffective tillers hilleffective tillers hill----1111:::: row spacing, seedling number hill-1 and the interaction had significant influence on transplant aus rice (table 2). the highest number of non-effective tillers hill-1 (6.69) was observed in s1 and the lowest one (5.22) in closer spacing of s4 reduction in the number of non-effective tiller in widely populated area might be due to plant can able to produce effective tiller at later growth stages which was in agreement with those of baloch et al. (2002). it was observed that the highest number of non-effective tillers hill-1 (7.17) was found in s1n1 and the lowest one (4.00) in s4n3. length of panicle length of panicle length of panicle length of panicle (cm):(cm):(cm):(cm): the longest panicle length (23.35 cm) was produced by 20 cm × 25 cm spacing and the shortest one (20.97 cm) by 20cm × 10 cm. similar results was observed by lious (1987) who stated that closer spacing decreased panicle length. the longest panicle length (24.40 cm) was produced by 4 seedlings hill-1 and the shortest one (20.02 cm) by 1 seedlings hill-1. number of grains paniclenumber of grains paniclenumber of grains paniclenumber of grains panicle----1111:::: the highest number of grains panicle-1 (128.79) was observed in 20 cm × 25 cm spacing while lowest number of grains panicle-1 (104.17) in 20 cm × 10 cm spacing. reduction in the number of grains panicle-1 under closer spacing might be due to increased number of plants per unit area. this increased number of plants per unit area exerted competition among plants for nutrients and light that might have caused lower crop growth rate with consequently a reduction in the number of filled grains panicle-1 which was supported by sarker et al. (2002) and ghosh et al. (1988). it was found that more seedling with higher no. of grains while less no. of seedling produced lowest (111.30) number of grains panicle-1. 20 ninad et al. number of sterile number of sterile number of sterile number of sterile spikelet’sspikelet’sspikelet’sspikelet’s paniclepaniclepaniclepanicle----1111:::: result revealed that the number of sterile spikelets panicle-1 decreased with increasing row spacing. the highest number of sterile spikelets panicle-1 (27.06) was found in 1 seedling hill-1. the highest number of sterile spikelets panicle-1 (30.50) was obtained from 20 cm × 10 cm with 1 seedlings hill-1 and the lowest one (20.00) from 20 cm × 25 cm with 4 seedlings hill-1. thousandthousandthousandthousand----grain weight (g):grain weight (g):grain weight (g):grain weight (g): the highest 1000-grain weight (23.30g) was recorded from 20 cm × 25 cm spacing and the lowest one (22.51g) from 20 cm × 10 cm spacing. 1000-grain weight decreased with increasing plant density in rice which was obtained by baloach et al. (2002) and yan et al. (2007). result revealed that 4 seedling hill-1) showed highest 1000 grains weight (24.20g) while 1 seedling hill-1 showed the lowest 1000 grains weight (21.87g). similar findings were observed by wen and yang (1991). in interaction, the highest 1000grain weight (24.60g) was found in s4n3 and lowest one (21.57g) in s1n1. grain yield (thagrain yield (thagrain yield (thagrain yield (tha----1111):):):): grain yield was significantly influenced by spacing, number of seedlings hill-1 and the interaction (fig. 1, 2 & 3). the highest (3.06 tha-1) grain yield was recorded in 20 cm × 10 cm spacing and the lowest grain yield (2.47 tha-1) in wider row spacing of 20 cm × 25 cm. the highest grain yield was recorded in closer spacing might be due to highest number of plants per unit area which was supported by neelam and nisha (2000) kang et al. (2001) and baloach et al.(2002). result revealed that more seedling showed the highest grain yield (2.98 tha-1) where the lowest grain yield (2.47 tha-1) with 1 seedling hill-1. similar results were also found by islam et al. (2002) and obulamma et al. (2002). the interaction between 20 cm × 10 cm with 4 seedlings hill-1 produced the highest grain yield (3.40 tha-1) and 20 cm × 25 cm with 1 seedlings hill-1 produced the lowest grain yield (2.21 tha-1). straw yield (thastraw yield (thastraw yield (thastraw yield (tha----1111): ): ): ): straw yield was significantly influenced by spacing, number of seedlings hill-1 and their interaction (fig. 1, 2 & 3). the highest straw yield was recorded in 20 cm × 10 cm spacing (3.37 tha-1) and the lowest in 20 × 25 cm spacing (3.07 tha-1). the result is consistent with the findings of baloach et al. (2002). result revealed that 4 seedling hill-1 showed the highest straw yield (3.61 tha-1), while the lowest straw yield (2.92 tha-1) with 1 seedling hill-1. the results found by karmakar et al. (2002) and shrirame et al. (2000) were similar with the findings. the interaction between 20 cm × 10 cm with 4 seedlings hill-1 produced the highest straw yield (3.75 tha-1) and 20 cm × 25 cm with 1 seedling hill-1 produced the lowest straw yield (2.78 tha-1). harvest index (%) :harvest index (%) :harvest index (%) :harvest index (%) : the highest harvest index was observed in wider row spacing of 20 cm × 10 cm (47.63%) and the lowest one (44.52%) from the spacing of 20 cm × 25 cm. result revealed that 4 seedlings hill-1) showed the highest harvest index (47.12%) where the lowest (45.69 %) with 1 seedling hill-1 which was also achieved by karmakar et al. (2002), shrirame et al. (2000) and bina (1993). the interaction between 20 cm × 10 cm with 4 seedlings hill-1 produced the highest harvest index (47.55%) and 20 cm × 25 cm with 1 seedlings hill-1 produced the lowest harvest index (44.34%). 21 effect of spacing and seedling per hill on the performance table 1. effect of spacing and number of seedling hill-1 on plant height, number of leaves hill-1 and number of total tillers hill-1 of aus rice at different days after transplanting (dat) treatment plant height (cm) leaves hill-1 (no.) total tillers hill-1(no.) spacing 35 dat 55 dat 75 dat at harvest 35 dat 55 dat 75 dat 35 dat 55 dat 75 dat at harvest s1 60.00a 79.22a 99.99a 104.27a 21.03 29.11a 35.80a 7.28d 10.28d 15.81d 22.86a s2 59.11ab 78.67ab 99.66a 103.72a 20.23 28.33a 34.94ab 8.44c 11.28c 17.39c 21.96b s3 58.00bc 78.67ab 96.56b 100.90b 19.11 28.72a 33.93bc 8.89b 12.17b 18.11b 21.14c s4 57.67c 77.67b 96.36b 100.75b 20.01 26.42b 32.82c 10.17a 13.00a 19.44a 20.34d level of significance ** * ** ** ns ** ** ** ** ** ** seedling hill-1 n1 57.17b 76.25c 94.58c 99.22b 14.35c 29.11c 30.91c 6.12c 9.83c 15.23c 19.85c n2 57.42b 78.67b 98.68b 103.67a 19.63b 28.33b 32.42b 8.96b 11.79b 18.13b 21.41b n3 61.50a 80.75a 101.16a 104.35a 26.32a 28.72a 39.80a 11.00a 13.42a 19.71a 23.47a level of significance ** ** ** ** ** ** ** ** ** ** ** interaction s1n1 56.33 77.00 95.67eg 101.60cd 15.60 21.83g 32.17ce 5.33h 8.50 14.10i 21.20ef s1n2 57.67 79.33 97.33df 107.19b 19.83 30.00de 34.00c 8.00e 10.50 16.33fg 22.73c s1n3 63.00 82.00 107.00a 111.56a 27.67 36.00a 41.67a 8.50de 11.83 17.00ef 24.65a s2n1 58.00 76.00 95.00fg 98.92df 14.77 20.00h 32.17ce 6.00gh 9.00 14.83hi 20.47g s2n2 59.00 77.33 98.67d 100.00cf 19.33 29.00ef 31.00de 8.83d 11.33 17.83de 21.50e s2n3 62.00 80.33 104.30b 106.67b 26.60 35.50a 41.23a 10.50c 13.50 19.50bc 23.90b s3n1 57.00 76.67 94.00g 99.04df 13.67 20.17h 29.80de 6.17g 10.33 15.50gh 19.30h 22 ninad et al. treatment plant height (cm) leaves hill-1 (no.) total tillers hill-1(no.) spacing 35 dat 55 dat 75 dat at harvest 35 dat 55 dat 75 dat 35 dat 55 dat 75 dat at harvest s3n2 58.33 80.00 96.00dg 98.00ef 20.00 32.00c 32.33cd 9.00d 12.33 18.67cd 21.13f s3n3 61.00 81.00 101.67c 105.67b 23.67 34.00b 39.67a 11.50b 13.83 20.17b 23.00c s4n1 56.00 75.33 93.67g 97.30f 13.37 19.97h 29.50e 7.00f 11.50 16.50fg 18.42i s4n2 56.00 78.00 96.32dg 100.64ce 19.33 28.00f 32.33cd 10.00c 13.00 19.67bc 20.27g s4n3 60.00 79.67 98.09de 102.33c 27.33 31.30cd 36.63b 13.50a 14.50 22.17a 22.34d level of significance ns ns ** ** ns ** ** ** ns ** ** cv (%) 3.21 2.40 3.50 3.64 7.45 3.10 4.17 5.00 4.31 3.33 3.89 in a column, values followed by similar letter (s) did not differ significantly by dmrt at ≤5% level of significant note: ns = not significance s1 = 20 cm x 10 cm, s2 = 20 cm x 15 cm, s3 = 20 cm x 20 cm, s4 = 20 cm x 25 cm n1 = 1 seedling, n2 = 2 seedlings, n3 = 3 seedling 23 effect of spacing and seedling per hill on the performance table 2. effect of spacing and number of seedling hill-1 on the yield attributes of aus rice treatment effective tillers hill-1 (no.) noneffective tillers hill-1(no.) panicle length (cm) grains panicle-1 (no.) sterile spikelets panicle-1 (no.) 1000 grains weight (g) harvest index (%) spacing s1 18.24d 6.69a 20.97d 104.17d 28.94a 22.51d 47.63a s2 19.74c 6.12b 21.88c 110.72c 26.55b 22.80c 45.62b s3 20.41b 5.70bc 22.63b 112.83b 23.62c 23.08b 45.05bc s4 21.24a 5.22c 23.35a 128.79a 21.69d 23.30a 44.52c level of significance ** ** ** ** ** ** ** seedling hill-1 n1 17.75c 6.54a 20.02c 111.30c 27.06a 21.87c 45.69c n2 20.10b 6.42a 22.21b 113.71b 25.14b 22.69b 46.31b n3 21.87a 4.84b 24.40a 117.38a 23.40c 24.20a 47.12a level of significance ** ** ** ** ** ** ** interaction s1n1 16.25h 7.17a 18.73 101.67h 30.50a 21.57j 47.15ab s1n2 18.25f 7.17a 20.75 104.00g 29.50b 22.15h 47.20ab s1n3 20.22d 5.75bc 23.42 106.83f 26.83c 23.80d 47.55a s2n1 17.25g 6.67ab 19.82 106.50f 29.08b 21.80i 45.31df s2n2 20.68d 6.68ab 21.83 111.33e 26.20c 22.50g 46.40bc s2n3 21.28c 5.00cd 24.00 114.33cd 24.37d 24.10c 46.17df s3n1 18.50f 6.50ab 20.40 110.50e 25.23d 22.03h 44.97ef s3n2 20.22d 6.00bc 22.83 113.00d 23.20ef 22.90f 45.54ce s3n3 22.50b 4.60de 24.67 115.00c 22.42fg 24.30b 46.63ef s4n1 19.00e 5.83bc 21.13 126.53b 23.42e 22.09h 44.34f s4n2 21.25c 5.83bc 23.42 126.50b 21.67g 23.20e 46.09cd s4n3 23.47a 4.00e 25.50 133.33a 20.00h 24.60a 45.80cd level of significance ** ** ns ** ** ** ** cv (%) 7.45 12.26 5.54 6.73 11.29 3.43 4.03 note: ns= not significance in a column, values followed by similar letter(s) did not differ significantly by dmrt at p ≤ 5 s1 = 20 cm x 10 cm, s2 = 20 cm x 15 cm, s3 = 20 cm x 20 cm, s4 = 20 cm x 25 cm n1 = 1 seedling, n2 = 2 seedlings, and n3 = 3 seedling 24 ninad et al. fig. 1. effect of spacing on the grain and straw yield (t ha aus rice fig. 3. effect of interaction between spacing and number of seedling hill effect of spacing on the grain and straw yield (t ha-1) of fig. 2. effect of number of seedling hill-1 on the grain yield (t ha-1) of aus rice effect of interaction between spacing and number of seedling hill-1 on the grain and straw yield (t ha-1) of aus on the grain and straw aus rice 25 effect of spacing and seedling per hill on the performance conclusionconclusionconclusionconclusion based on the present study it may be concluded that the aus rice var. brri dhan48 grown under 20 cm × 10 cm spacing with 4 seedlings hill-1 could obtained optimum grain yield. however, these findings need to be further investigated and evaluated on different agroecological zone before final recommendation to the farmers. referencesreferencesreferencesreferences abbas, m., m. p. singh, k. b. nigam and v. s. kandalkar. 1994. effect of phosphorus and hill density on yield and yield attributing characters of rice. indian j. agron. 39(2): 249-251. baloch, a. w., a. m. soomro, m. a. javed and m. ahmed. 2002. optimum plant density for high yield in rice. asian j. plant sci. 1: 25-27. bbs (bangladesh bureau of statistics). 2001. statistical yearbook of bangladesh, bangladesh bureau of statistics. stat. div. minis. plann., govt. people's rep. bangladesh. dhaka. p. 138. bbs (bangladesh bureau of statistics). 2015. estimates of boro rice (husked), 2014-15. pp. 1-6. bina ((bangladesh institutye of nuclear agriculture) 1987. annual report, 1986-87. bangladesh inst. nucl. agric. p.o. box no. 4. mymensingh. p. 165. bina (bangladesh institutye of nuclear agriculture) 1993. annual report, 1992-93. bangladesh inst. nucl. agric. p.o. box no. 4. mymensingh. pp. 143-147. chowdhury, m. j. u., a. u. sarker, m. a. r. sarkar and m. a. kashem. 1993. effect of variety and number of seedlings hill-1 on the yield and its components of late transplant aman rice. bangladesh j. agril. sci. 20(2): 311-316. fao (food and agricultural organization). 2005. fao production year book. food and agricultural organization, rome. 59: 54. ghosh, b. c., m. d. reddy and b. b. reddy. 1988. effect of seedling density on growth and yield of transplanted rice in an intermediate deep water situation. thai j. agril. sci. 21(10): 1321. gomez k. a. and a. a. gomez. 1984. statistical procedures for agricultural research. a wiley int. sci. pub. john wiley and sons, new york, brisbane, singapore. p.139 islam, m. r., m. a. salam, m. a. harman and m. a. r. sarkar 2002. effect of hill density and number of seedlings hill-1 on the yield and yield components of fine rice cv. kalizira. bangladesh j. agril. sci. 29(2): 325-328. kang, y. k., h. t. kim, n. k. cho and y. c. kim. 2001. effect of planting date and plant density on yield and quality of rice in jeju. korean j. crop sci. 46: 95-99. karmakar, b., m. a. r. sarkar, m. r. uddin and m. biswas. 2002. effect of row arrangements, number of seedlings hill-1 and nitrogen rates on yield and yield components of late transplant aman rice. bangladesh. j. agri1. sci. 29(2): 275-281. miah, m. h. n., m. a. karim, m. s. rahman and m. s. islam. 1990. performance of nizersail mutants under different row spacings. bangladesh j. train. dev. 3(2): 31-34. 26 ninad et al. neelam, k. c. and c. nisha. 2000. effect of row spacing and nitrogen level on growth, yield and seed quality of scented rice under transplanted condition. indian j. agron. 45: 45: 304306. obulamma, u., r. reddepa and r. reddy. 2002. effect of spacing and seedling number on growth and yield of hybrid rice. j. res. angrau. 30(1):76-78. sarker, g., m. rahman, r. hasan and s. c. roy. 2002. system of rice intensification: yield and economic potential in boro rice at different locations of bangladesh. life-nopest project, care-bangladesh. p. 1-5. shah, m. h., m. k. khushu, b. a. khanday, and a. s. bali. 1991. effect of spacing and seedlings per hill on transplanted rice under late sown condition. indian j. agron. 36(2): 274-275. shrirame, m. d., h. j. rajgire and a. h. rajgire. 2000. effect of spacing and seedling number hill1on growth attributes and yield of rice hybrids under lowland condition. j. soils crops. 10(1):109-113. bangladesh agron. j. 2018, 21(2): 73-78 agro-economic performance of intercropping hybrid maize with vegetables and spices at farmer’s field m. i. nazrul senior scientific officer, on-farm research division, bangladesh agricultural research institute (bari) corresponding author, email: mi_nazrul@yahoo.com; m.i.nazrul@gmail.com (received: 4 december 2018, accepted: 9 april 2019) keywords: intercropping, maize, vegetables, spices, yield, cost-benefit abstract the experiment was conducted at multi location testing (mlt) site, moulvibazar, bangladesh during rabi season of 2016-17 and 2017-18 to study the profitability of intercropping of hybrid maize with vegetables and spices. five intercrop combinations of hybrid maize along with sole maize were arranged in randomized complete block design (rcbd) replicated six times. there were six treatments viz., t1: maize + potato, t2: maize + red amaranth, t3: maize + spinach, t4: maize+ data shak, t5: maize + coriander and t6: maize as sole. the grain yield of maize in intercropped combination varied significantly. the highest grain yield (9.71 t ha-1) was in sole maize. the highest maize equivalent yield 15.60 t ha-1 was recorded from the treatment t1 (100% maize + potato) whereas the lowest yield (8.61 t ha-1) was obtained from the treatment t6 (sole maize). the highest gross return (tk. 312000 ha -1) and benefit cost ratio (3.29) was obtained from the treatment t1 (100% maize + potato). on the contrary, the lowest gross margin (tk. 101600 ha-1) was obtained from treatment t2 (maize + red amaranth). it revealed that the combination of maize with potato was more compatible and profitable intercropping system in sylhet region of bangladesh. introduction maize is a very common, popular and multi uses cereal crop at present situation over the world. every year a huge amount of maize grain is required as feed and fodder for poultry and livestock sector and most of them are imported (pandey and koirala. 2017). maize can be used as alternative crop of rice or wheat to fulfill the food demand for the increasing population in our country. the climate of bangladesh is suitable for maize cultivation. popularity of maize cultivation is increasing day by day of our country. it is generally grown in our country during winter season. most of the farmers grow maize as a sole crop in this region but maize is a long duration crop. in that case, farmers can easily cultivate different short duration vegetables and spice crops with maize in existing cropping pattern. intercropping has already recognized as a potentially beneficial system of crop production. it is traditional practice in bangladesh. it increases (marshal and willey, 1983; quayum et al., 1999; caruford, 2000) total productivity by judicious choice of compatible crops, by adopting appropriate planting geometry, inter/intra specific competition may be minimized resulted efficient use of natural resources. through intercropping system the total crop production and income of per unit area will be increased (akanda and quayyum, 1982; shaheb and nazrul, 2014). intercropping can play an important role in increasing vegetable production (rashid, 1987). so, suitable crop combinations need to be identified through better compatibility. besides, intercropping increased total production (rahman, 1999 and mondol et al., 1999) and greater profit about:blank 74 m.i. nazurl margin and utilize higher resource use efficiency (hashem and moniruzzaman, 1986). hence, the present experiment was conducted to increase yield and economic return of farmers and improve the productivity of existing cropping pattern as well as land bring under cultivation by intercropping practices in sylhet region. materials and methods the experiment was conducted at multi location testing (mlt) site, moulvibazar during rabi season of 2016-17 and 2017-18 to study the feasibility of intercropping of hybrid maize with different short duration vegetables and spices and economic returns. five intercrop combinations of hybrid maize along with sole maize were arranged in randomized complete block design replicated six times. there were six treatments viz., t1: maize + potato, t2: maize + red amaranth, t3: maize + spinach, t4: maize + data shak, t5: maize + coriander and t6: maize as sole. the unit plot size was 8 m × 5 m. hybrid maize (var. bari hybrid maize-9). potato (var. diamant), spinach (var. local), red amaranth (var. bari lalshak-1), and coriander (var. local) were used as component crops. the seeds of maize, potato, spinach, red amaranth, data shak, and coriander were sown during 25-28 november in each year with maintaining recommended methods. the spacing for sole and intercropping maize was 60 cm  25 cm. fertilizers were applied @ 255-55-1-40-40-6-2 kg ha-1 n-p-k-zn-b for maize. one-third n and full amount of all other fertilizer were applied as basal. rest n was applied as top dress in two equal splits at 30 and 60 days after sowing (das). subsequently three irrigations were applied at 20, 30 and 60 das. ear thing up was done at 30 days after planting potato. two hand weeding were done at 20 and 25 das to keep the crop reasonably weed free. the component crops were harvested 10-20 february and maize harvested from 1012 may, 2016-17 and 2017-18. ; ten maize plants were randomly selected prior to harvest from each plot; yields of companion were collected from whole plot basis. at harvest, the yield data was recorded plot wise and analyzed statistically and mean separations were done by lsd using statistical tools for agricultural research (star) package. maize equivalent yield (mey) and benefit cost analysis also done. grain yield of maize was determined at 14% moisture content. equivalent yield of component crops were determined following the method of anjaneyulu et al. (1982). maize equivalent yield (mey) =ym + (yi × pi)/pm where, ym = yield of maize (t ha-1) yi = yield of intercrop vegetable (t ha-1) pi = price of intercrop vegetables (tk ha-1) pm = price of maize (tk ha-1) the relative yield was obtained by dividing the intercrop yield of a crop with the respective sole crop yield of that crop using the formula (dewit and vander bergh, 1965). the relative yield of crops = yield of components crops yield of sole crops results and discussion agro-economic performance of intercropping hybrid maize 77 effect on yield and yield components of maize pooled analysis was done as there was no difference in characters in years. among the yield and yield contributing characters of intercropped maize cob length and stover yields were not statistically significant (table 1). however, agronomic performance of sole maize was a little bit higher than the treatments. the highest grain yield (9.71 t ha-1) was recorded from sole maize that was statistically similar with t4 (maize + data shak) and t1 (maize + potato) and t5 (maize + coriander), which could be due to higher weight of cobs, no. of grains/cob and 1000-grain weight. on the other hand, the lowest grain yield 7.17 t ha-1 was recorded from t3 (maize + spinach). the yield data indicated that there was not significant yield loss of maize due to intercropped with potato, data shak and coriander. table 1. yield and yield contributing characters of maize under different intercropping situation at moulvibazar crop combinations plant height (cm) cob length (cm) weight of cob (g) grains cob-1 1000 grain wt. (g) grain yield (t ha-1) stover yield (t ha1) t1:maize + potato 194.00 13.70 103.13 151.83 353.33 9.60 11.86 t2:maize + red amaranth 151.63 13.60 118.67 191.10 214.67 7.20 10.94 t3:maize + spinach 195.40 15.97 114.33 210.03 230.67 7.17 11.12 t4:maize + data shak 182.93 15.00 105.00 209.63 358.00 9.70 11.93 t5:maize + coriander 203.83 15.00 129.50 208.87 291.00 9.39 11.50 t:maize as sole 203.83 14.33 134.37 240.80 382.00 9.71 11.84 cv (%) 2.93 10.44 6.47 11.08 7.79 4.51 3.91 lsd (0.05) 15.67 ns 21.57 63.49 69.06 1.13 ns effect of intercrops the intercrop yield of potato, red amaranth, spinach, data shak and coriander were influenced significantly by different intercropping combinations (table 2). the maximum yield of component crops (potato) was recorded from maize + potato intercropping combination followed by spinach combination. the lowest yield was obtained from maize + coriander intercropping combination. relative yield relative yield determines competitive ability of component crops in intercropping system. greater value of relative yield showed more competitive ability in intercrop situation compared to its monoculture (juskiw et al., 2000). the relative yields of maize were 0.99, 0.74, 0.75 0.99 and 0.97 when maize was intercropped with potato, red amaranth, spinach, data shak and coriander, respectively (table 2). this indicates that maize yield was reduced by 1%, 26%, 25%, 1%, and 3% of sole crop when it was intercropped with potato, red amaranth, spinach, data shak and coriander, respectively. the lower relative yield of maize in intercropping indicated that the crop faced competition for space, nutrients, light, and water with component crops. the findings are in agreement with that of singh (1993) and rahman (1999). maize equivalent yield all the intercropped combinations showed higher maize equivalent yield than sole maize in all cases. among the treatments, significantly the highest maize equivalent yield (15.60 t ha-1) was obtained from maize + potato intercrop 74 m.i. nazurl combination (table 2). though highest grain yield was recorded from sole maize but equivalent yield and economic return was much lower than other treatment. similar results were observed by researchers rahaman, et al., 2015 and hossain, et al., 2015. the lowest maize equivalent yield (9.53 t ha-1) was obtained from maize + red amaranth intercrop combination. although maize yield was 1%, 26%, 25%, 1%, and 3% lower than sole crop when it was intercropped with when it was intercropped with potato, red amaranth, spinach, data shak and coriander. but maize equivalent yield from maize + potato, maize + red amaranth, maize + spinach, maize + data shak and maize + coriander intercrop combination showed 81%, 11%, 14%, 52% and 51% higher yield advantage over the sole maize, respectively. sarker et al. (2013) reported that the lowest maize equivalent yield, gross margin and benefit cost ratio were obtained from sole crop of maize. this result showed that maize + potato was the best intercrop combination in respect of total yield advantage followed by maize + data shak and maize + coriander inter cropping system. table 2. grain yield of sole maize, intercrop yield, relative yield and equivalent yield of maize as influenced by intercropping with vegetables and spices at moulvibazar. crop combinations grain yield (t ha-1) intercrop yield (t ha-1) relative yield of maize maize equivalent yield (t ha-1) t1:maize + potato 9.60 10.00 0.99 15.60 t2:maize +red amaranth 7.20 5.83 0.74 9.53 t3:maize + spinach 7.17 6.78 0.75 9.88 t4:maize + data shak 9.70 5.69 0.99 13.11 t5:maize + coriander 9.39 2.95 0.97 13.08 t6:maize as sole 9.71 0.00 1.00 8.61 cv (%) 4.51 lsd (0.05) 1.13 monetary advantage an analysis on cost and return of intercropping maize with different short duration components crops have been presented in table 3. higher gross return was obtained from all intercrop combinations than sole crop. many researchers also documented higher gross margin or net return in intercropping system than sole crop (ali, et al., 2015; alam et al., 2008; bhuiyan et al., 2013; farhad et al., 2014; rahaman, et al., 2015 and hossain, et al., 2015). among the combinations, the highest gross return was obtained from maize + potato intercropping system, which was 81% higher than sole maize. almost similar trend was followed in case of gross margin. the higher benefit-cost ratio (bcr) was recorded from maize + garden pea combination followed by maize + bush bean. table 3. monetary advantage analysis of maize intercropping with vegetables and spices at moulvibazar (average of 2 years) crop combinations maize equivalent yields (t ha1) gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio t1:maize + potato 15.60 312000 209000 103000 3.29 t2:maize+red amaranth 9.53 190600 89000 101600 2.14 t3: maize + spinach 9.88 197600 91000 106600 2.17 agro-economic performance of intercropping hybrid maize 77 t4: maize + data shak 13.11 262200 94750 167450 2.77 t5: maize + coriander 13.08 261600 94500 167100 2.77 t: maize as sole 8.61 172200 70000 102200 2.46 price (tk. kg-1): maize20.00; potato12.00; red amaranth8.00; spinach8; data shak12.00 and coriander25.00 conclusion and recommendation from these results, it revealed that maize grown as intercrop with short duration component crops (vegetables/spices) like potato, data shak and coriander may be profitable than sole maize. all of the intercrop combinations except red amaranth and spinach are agronomically and economically viable than sole cropping. the overall results indicated that among the intercrop combinations maize sowing with potato was found suitable for total productivity and economic return of inter crop systems in sylhet region. references akanda, m. e. and m. a. quayyum. 1982. effect of intercropping mung bean, blackgram, soybean, cowpea and groundnut with maize. bangladesh j. agril. res. 7(1): 66-69. ali, m.r.m., s. rahman, m. asaduzzaman, m.m. hossain and m.a. mannan. 2015. intercropping maize with different vegetables. bangladesh agron. j. 18(1): 4952. alom, m. s., n. k. paul and m. a. quayyum. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean in different planting methods. saarc j. agri. 6:73-82. anjaneyulu, v. r., s. p. singh and m. pal. 1982. effect of competition free period and technique and pattern of pearl millet planting on growth and yield of mungbean, and total productivity in solid pearl millet and pearl millet/mungbean intercropping system. indian j. agron. 27(3):219-226. bhuiyan, m. s., s. k. bhowal, i. s. farhad, m. m. u. chowdhury, and m. amin. 2013. intercropping soybean with kaon in varying plant population in the coastal area of noakhali region. bangladesh agron. j. 16(1): 81-86. dewit, c. t. and j. p. vander bergh, 1965. competition between herbage plants. neth. j. agric. sci. 13: 212-221. farhad, i. s. m. u. a. chowdhury, s. k. bhowal and a. s. m. m. r khan. 2014. chilli-garlic intercropping system in coastal saline area. app. sci. report. psci publications. 2(2): 47-50. hasem, a and a. f. m. moniruzzaman. 1986. effect of intercropping maize with cowpea at varying plant population levels. bangladesh j. agron. 1: 25-39. hossain, m. h., s. k. bhowal, a. s. m. m. r. khan. 2015. intercropping system of maize with different winter vegetables. malays. j. med. biol. res. vol. 2(2). mondol, m. r. i., m. r. khan, m. a. ali, m. n. islam and m. a. mannan. 1999. a study on intercropping sesame with groundnut. bangladesh j. agril. res. 24(4): 657-662. pandey, p. r. and k. b. (eds.) koirala. 2017. best practices of maize production technologies in south asia. saarc agriculture centre, dhaka: p145. 74 m.i. nazurl quayyum, m. a., m. e. akanda and t. islam. 1985. effect of intercropping maize with groundnut at varying levels of plant population and nitrogen levels, bangladesh j. agric.10(3):1-6. rahaman, m. a., m. m. rahman, s. roy, m. ahmed and m. s. bhuyan. 2015. on-farm study on intercropping of hybrid maize with different short duration vegetables in the charland of tangail. bangladesh agron. j. 2015, 18(2): 65-69. rahman, m. a. 1999. comparative performance of intercropping in pulse and oil seeds with rainfed wheat (triticum aestivum) in bangladesh. indian j. agron. 44 (3): 504-508. sarker, u. k., s. dey, s. kundu and m. a. awal. 2013. on-farm study on intercropping of hybrid maize with short duration vegetables. j. bangladesh agril. univ. 11(1): 1-4. shaheb, m. r and m. i. nazrul. 2014. production and economics of mixed intercropping of potato with other short duration vegetables. bangladesh agron. j. 17(2): 39-46. microsoft word baj 355c__press bangladesh agron. j. 2020, 23(1): 47-58 effect of sunflower residues and herbicide on weed suppression, grain yield and economics of transplanted aman rice s.s. tanu1, p. biswas2, s. ahmed2 and s.c. samanta2 1ms student, 2professor, dept. of agronomy, patuakhali science and technology university corresponding e-mail: samantapstu@yahoo.com (received: 25may, 2020, accepted: 07 august, 2020) keywords: sunflower residues, aman rice, butachlor, yield, weed index, gross margin abstract a field experiment was conducted at agronomy field laboratory, patuakhali science and technology university, dumki, patuakhali from july 2018 to november 2018 to evaluate the effect of sunflower residues and herbicides on the yield and economic performance of transplanted aman rice. weed control methods tested were t1 = weedy check (unweeded control), t2 = weed-free check by hand weeding twice, t3 = pendimethalin, t4 = pretilachlor, t5 = butachlor, t6 = pyrazosulfuron ethyl, t7 = bensulfuron methyl + acetachlor, t8 = bispyriback sodium, t9 = 2,4-d amine, t10 = mcpa, t11 = sunflower residues, t12 = sunflower residues + 100% pyrazosulfuron ethyl, t13 = sunflower residues + 75% pyrazosulfuron ethyl, t14 = sunflower residues + 50% pyrazosulfuron ethyl. the experiment was laid out in a randomized complete block design with fourteen treatments replicated thrice. weedy check registered significantly the highest total weed density (354.67 m-2) and total weed dry matter (51.81 g-2) while weed-free treatment by hand weeding twice recorded significantly the lowest total weed density (6.67 m-2) and total weed dry matter 0.49 g-2) . weedy check produced the highest weed index (34.24%) and hand weeding produced the lowest. among different herbicides applied alone, butachlor had the lowest total weed density (15 m-2) and total weed dry matter (6.43 g-2) after hand weeding. hand weeding recorded the highest grain yield (5.14 t ha-1) which was statistically similar to pendimethalin, pretilachlor, butachlor, bensulfuron methyl + acetachlor and sunflower residues + 100% pyrazosulfuron ethyl. higher grain yield was attributed to a higher number of panicle m-2, number of filled grains panicle-1 and 1000-grain weight. the highest gross margin (22955 tk. ha-1) and benefit-cost ratio (1.32) were obtained from butachlor. integration of sunflower residues with pyrazosulfuron ethyl produced effective weed suppression and satisfactory yield comparable to butachlor. although the integration is less profitable than butachlor the farmers can use this technology as a feasible and environmentally sound approach in transplanted aman rice field. introduction weeds are a major cause of yield reduction in rice and its control is labor intensive. hand weeding and other traditional control methods are time consuming and involve high labor costs. the climate as well as the edaphic condition of bangladesh is favorable for the growth of weeds. so, the rice crop is usually infested heavily with weeds resulting in grain yield reduction by 7080% for direct seeded aus rice (early summer), 30-40% for transplanted aman rice (late 48 tanu et al. summer), and 22-36% for modern boro rice (winter) (brri, 2008). weeds not only cause huge reductions in rice yields but also increase the cost of cultivation, reduce input efficiency, interfere with agricultural operations, impair quality, act as alternate hosts for several insect pests, diseases, affect the aesthetic look of the ecosystem as well as native biodiversity, affect human and cattle health (bhuiyan et al., 2017). weeds compete for nutrient, space, sunlight and moisture with rice resulting in crop yield loss. thus, weed is a serious threat for sustaining rice production in bangladesh and necessitates proper weed management for rice production. herbicidal weed control methods offer an advantage to save labor and money, as a result, regarded as cost-effective. chemical weed control is becoming popular in bangladesh mainly due to scarcity of labor during peak growing season and lower weeding cost. the early crop growth stage (up to 45–60 days of transplanting) is the most competitive for weeds and hence the crop growth is affected negatively (barua et al., 2008). therefore, both pre-emergence and post emergence herbicide works well in transplanted rice. due to high labor and huge time requirement for manual weeding, farmers of the coastal areas, particularly in kalapara upazila are forced to opt for other alternative measures like chemical weed control. phyrazosulfuron ethyl (an early post-emergence herbicide), pendimethalin (preemergenceherbicide ), and butachlor (pre-emergence herbicide)are being used for weed control in rice in this area. however, the indiscriminate use of herbicides poses serious problems, such as environmental pollution, human health hazards, developing weed resistance, depletion of crop diversity, and reduction of crop productivity (khanh et al., 2005). allelopathy is suggested to be a potentially safer method for weed control compared to the use of synthetic herbicides. jabran et al. (2015) reported that allelopathy has a pertinent significance for ecological, sustainable, and integrated weed management systems. many researchers reported that the incorporation of sunflower residues alone or in combination with lower doses of herbicides into field soil significantly reduced the weed population and dry weight over control (alsaadawi et al., 2011; saif et al., 2016; rawat et al., 2017). however, little information is available on the use of crop residues and herbicides for weed control in transplanted aman rice in bangladesh. therefore, this study was undertaken to investigate the effect of sunflower residues and herbicides on weed growth, yield, and economics of transplanted aman rice. materials and methods the experiment was conducted at the agronomy field laboratory of patuakhali science and technology university (pstu), dumki, patuakhali in high land during the period from july to november, 2018. the experimental site lies at 22ο27' n latitude and 90ο23' e longitude at an altitude of three-meter above the sea level. the experimental field belongs to the agro-ecological zone-13; ganges tidal floodplain. the texture of the soil was clay loam having ph 6.0, organic matter 1.38%, total n 0.09%, available p 6.30 ppm, exchangeable k 0.11 me/100g, available s 15.25 ppm, and available zn 0.46 ppm. there were fourteen weed control treatments included in the study. these were as follows: t1 = weedy check (unweeded control), t2 = weed-free check by hand weeding twice (at 20 and 40 dat), t3 = pendimethalin (pe), t4 = pretilachlor (pe), t5 = butachlor (pe), t6 = pyrazosulfuron ethyl (early post-emergence), t7 = bensulfuron methyl + acetachlor (pe), t8 = bispyriback sodium ((post-emergence), t9 = 2, 4-d amine (poe), t10 = mcpa (poe), t11 = sunflower residues (pe), t12 = sunflower residues (pe) + 100% pyrazosulfuron ethyl (early postemergence), t13 = sunflower residues (pe) + 75% pyrazosulfuron ethyl (early post-emergence) and t14 = sunflower residues (pe) + 50% pyrazosulfuron ethyl (early post-emergence). sunflower residues were studied in combination with pyrazosulfuron ethyl only because many of effect of sunflower residues and herbicide on weed suppression and yield of aman rice 49 the farmers of this region use this herbicide for weed control in rice. the experiment was laid out in a randomized complete block design with three replications. the layout was completed one day before transplanting. spaces of 1m and 0.5 m were maintained in between replication and unit plots, respectively. the individual plot size was 4 m × 2.5 m (10 m2). the variety brri dhan49 was used as planting material. fertilizer was applied @ 90-15-519-1 kg n, p, k, s, and zn ha-1, respectively through urea, triple super phosphate, muriate of potash, gypsum and zinc sulphate on a soil test basis. urea was applied in three equal splits; 1st at 15 days after transplanting (dat), 2nd at 30 dat and 3rd at 45 dat. the total amount of triple super phosphate, muriate of potash, gypsum and zinc sulphate was applied during final land preparation. thirty-two days old uniform seedlings were transplanted on 9 august 2018 at the rate of 2-3 seedlings hill-1 at a spacing of 20 × 20 cm. the herbicides used in this experiment are available in paddy growing area and their description with the rate and time of application is as follows: table 1. details of the herbicides used in the study trade name common name chemical family rate of application time of application panida 33ec pendimethalin dinitroaniline 2.50 l ha-1 5 dat super heat 500 ec pretilachlor chloroacetamide 1.0 l ha-1 5 dat amchlor 5g butachlor chloroacetamide 25 kg ha-1 5 dat super power 10wp pyrazosulfuron ethyl sulfonylurea 150 g ha-1 7 dat super mix 18 wp bensulfuran methyl+ acetachlor chloroacetamide + sulfonylurea 0.74 kg ha1 5 dat extra power 20wp bispyribac sodium pyrimidinylthiobenzoates 148 g ha-1 7 dat fielder 2, 4-d amine phenoxy-carboxylic acid 2.25 l ha-1 28 dat mcpa 500 mcpa phenoxy-carboxylic acid 988 ml ha-1 28 dat dat= days after transplanting liquid/powdery herbicides were sprayed uniformly with the spray volume of 500 l ha-1 for preemergence spray and 350 l ha-1 for post-emergence spray using a knapsack sprayer with a flat fan nozzle. the pre-emergence application was made on the soil surface with 5 cm water depth uniformly with minimum trampling. granular herbicide was broadcast uniformly on the soil surface by mixing with sand. hand weeding was carried on bund side and paths whenever the weeds emerged in order to keep the experimental site clean. in the weed-free treatment, the plots were kept weed free up to 40 dat by two hand weeding at 20 and 40 days after transplanting. weedy plots allowed season long weed infestation. at physiological maturity, heads of sunflower plants were removed and the plants were harvested, air-dried for several days under sun light and chopped into 2-3 cm pieces. sunflower plants were collected from the farmers’ field of sreerampur village of dumki upazila, patuakhali. chopped material was kept under room condition until use. the air-dried and chopped residues were incorporated in soil 3 days after transplanting of aman rice @ 5 t ha-1. data on weed density and dry weight were recorded at 45 dat randomly from 0.25 m2 (0.5 x 0.5 m) area and then converted to per square meter. dry weights of weeds were taken by drying them in an electric oven at 70οc until the constant weight was recorded. phyto-toxicity of herbicides on rice plants was determined visually (yellowing leaves, burning leaf tips, stunting growth etc.) according to the scale suggested by irri (1999). the rating of toxicity was done within a week (2nd, 4th, and 6th days) of herbicides application from 10 samples of 50 tanu et al. each plot. the mean rate was calculated from 10 sample plants of a unit field plot. the day of recovery from the toxicity was also recorded visually. the degree of toxicity on the rice plants was measured by the following scale. rating visual symptom effect 1 no effect no toxicity 2 yellowing leaves slightly toxicity 3 yellowing leaves and stunting moderate toxicity 4 burning leaves and leaf tips severe toxicity 5 burning plant, plant killed highly toxicity (plant killed) yield components were recorded from 10 random hills except for the harvest and border area. an area of 5.12 m2 (3.2 m x 1.6 m) was harvested from the centre of each plot to estimate grain and straw yields. after threshing and cleaning, the fresh weight of grain was recorded and adjusted to 14 % moisture content. straw yield was recorded after proper sun drying. weed index (wi) was calculated by using the following formula (misra and misra, 1997) weed index (%) = ��� � ×100 where, x = yield from weed free plots, y = yield from treated plots the cost of cultivation of each treatment was worked out. further the economic evaluation of each treatment was done by estimating the gross returns, net returns and benefit cost ratio. the price of the inputs at the time of their use and the prevailing market price of the products obtained were considered for working out the cost of cultivation, returns, and benefit-cost ratio. the collected data were statistically analyzed using the f-test. data on weed count and weed dry weight have shown a high degree of variation. therefore, the data on weed count and weed dry weight were subjected to square-root [(x + 0.5)0.5] transformation to make an analysis of variance more valid as suggested by chandel (1984). data were analyzed with star 2.0.1 software for analysis of variance and means were compared based on the least significant difference (lsd) test at the 0.05 probability level (gomez and gomez, 1984). results and discussion phytotoxicity of herbicides on rice plant the degree of toxicity of the herbicide to rice plants and the symptoms produced on the plant are presented in table 2.all the pre-emergence and early post-emergence herbicides showed no toxicity. angiras and kumar (2005) also found that the application of pyrazosulfuron ethyl showed no phytotoxic effect on rice plants. bhuiyan et al. (2018) reported no phytotoxic symptoms on rice with the application of combined herbicide like metolachlor + bensulfuron methyl. zahan et al. (2014) found a non-hazardous effect of pretilachlor on transplanted aman rice crop production. post-emergence herbicides 2, 4-d amine and mcpa showed burning of the lower leaves that recovered within 15 days. similar results were also reported by shibayama (1980) who observed the yellowing and burning of lower leaves of rice plants treated with phenoxy acetic acid herbicides. effect of sunflower residues and herbicide on weed suppression and yield of aman rice 51 table 2. toxicity level of different herbicidal treatments on transplanted aman rice plants treatments rating symptoms observed on rice crop toxicity level pendimethalin (pe) 1.0 no effect no toxicity pretilachlor (pe) 1.0 no effect no toxicity butachlor (pe) 1.0 no effect no toxicity pyrazosulfuron ethyl (early post-emergence) 1.0 no effect no toxicity bensulfuron methyl + acetachlor (pe) 1.0 no effect no toxicity bispyriback sodium (postemergence) 1.0 no effect no toxicity 2, 4-d amine (poe) 3.67 burning of lower leaves toxicity mcpa (poe) 3.67 burning of lower leaves toxicity sunflower residues (pe) + 100% pyrazosulfuron ethyl (early post-emergence) 1.0 no effect no toxicity sunflower residues (pe) + 75% pyrazosulfuron ethyl (early-post emergence) 1.0 no effect no toxicity sunflower residues (pe) + 50% pyrazosulfuron ethyl (early-post emergence) 1.0 no effect no toxicity pe = pre-emergence, poe = post-emergence effect of weed control methods weed density all the weed control methods reduced the mean density of total weeds as compared to the weedy check (table 3). non-treated weedy check recorded the highest total mean weed density (354.67 plants m-2) and weed-free treatment by hand weeding recorded the lowest density (6.67 plants m-2). akbar et al. (2011) reported that hand pulling resulted in higher weed suppression than in chemical weed control. table 3. effect of weed control methods on weed prevalence at 45 days after transplanting of transplanted aman rice treatments weed density (no. m-2) weed dry weight (gm-2) t1 18.81 a (354.67) 7.22 a (51.81) t2 2.67 i (6.67) 0.97 h (0.49) t3 6.34 fg (40.00) 3.05 b-d (8.83) t4 5.92 g (34.67) 2.98 c-e (8.37) t5 3.90 h (15.00) 2.63 ef (6.43) t6 7.80 de (60.34) 3.22 bc (9.91) t7 3.95 h (15.33) 2.68 d-f (6.78) t8 7.24 ef (52.00) 3.20 bc (9.80) t9 9.35 bc (87.00) 3.39 b (10.98) t10 8.40 cd (70.67) 3.26 bc (10.15) t11 9.75 b(94.66) 3.44 b (11.34) t12 5.80 g (33.33) 1.97 g (3.39) t13 7.33 ef (53.67) 2.58 f (6.14) t14 8.58 cd (73.35) 2.94 c-f (8.16) ls ** ** lsd(0.05) 1.0174 0.3952 cv (%) 8.02 7.57 t1 = weedy check, t2 = weed-free check by hand weeding twice, t3 = pendimethalin, t4 = pretilachlor, t5 = butachlor,t6 = pyrazosulfuron ethyl, t7 = bensulfuron methyl + acetachlor, t8 = bispyriback sodium, t9 = 2, 4-d amine, t10 = mcpa, t11 = sunflower residues, t12 = sunflower residues + 100% pyrazosulfuron ethyl, t13 = sunflower residues + 75% pyrazosulfuron ethyl, t14 = sunflower residues + 52 tanu et al. 50% pyrazosulfuron ethyl, ls = level of significance. figures in parentheses are original values. figures in a column followed by different letters differ significantly, but with common letter (s) do not differ significantly at 5% level of probability. butachlor and bensulfuron methyl + acetachlor were similar in controlling total weed density and significantly reduced the total weed density over a weedy check and other herbicides tested alone or in combination with sunflower residues. application of butachlor at 1.25 kg a.i. ha-1 gave efficient weed control in rice as reported by hasanuzzaman et al. (2008). singh et al. (2005) observed that bensulfuron methyl (londax) at different doses (40 g a. i. ha-1 and 50 g a.i. ha-1) applied alone or as tank mixture with butachlor @ 1000 g a.i. ha-1 reduced the density of all the sedges and broad-leaved weeds. the lower weed density was due to their higher efficacy to control weeds in rice. both the herbicides reduced the total mean weed density by about 96% as compared to the weedy check. the herbicides 2, 4-d amine and mcpa were the worst regarding weed control. 2, 4-d amine and mcpa being broad leaf killer, they only picked broadleaved weeds, while the grasses escaped its control. hence their overall effect was lesser as compared to other herbicides. sunflower residue incorporated alone resulted in 73.31% control of the total weed population. sunflower residue along with 100%, 75% and 50% pyrazosulfuron ethyl resulted in 90.60%, 84.87% and 79.32% reduction of total weed density, respectively over weedy check. however, the use of 50% of the recommended dose of pyrazosulfuron ethyl coupled with sunflower residue scored statistically similar suppression of total weed density to that achieved with the recommended dose (100%) of the same herbicide used alone. weed dry weight the observation on weed dry matter recorded from different weed control treatments at 45 dat is presented in table 3. in general, all weed control treatments significantly reduced the total weed dry weight compared with non-treated plots. the minimum weed dry weight of weeds was recorded from manual weeding (0.49 g m-2) and the maximum weed dry weight was recorded in weedy check (51.81 g m-2). among the sole herbicide treatments, butachlor registered the lowest weed dry weight (6.43 g m-2) and 2, 4-d amine the highest (10.98 g m-2). none of the treatments were compared to manual weeding in reducing total weed dry weight. however, sole application of sunflower residue and sole application of pyrazosulfuron ethyl at the recommended dose recorded statistically similar total weed dry weight indicating the allelopathic properties of sunflower. sunflower residues + 50% pyrazosulfuron ethyl, sunflower residues + 75% pyrazosulfuron ethyl, butachlor, and bensulfuron methyl + acetachlor were statistically similar and better than all other herbicides tested in reducing total weed dry weight. raj et al. (2016) reported that total weed dry biomass at the harvesting of rice was significantly reduced by pre-emergence application of pendimethalin, butachlor and bispyriback sodium over weedy check. yield attributes data pertaining to yield components are presented in table 4. plant height was significantly affected by different weed control treatments. among weed control treatments, manual weeding recorded the highest plant height (101.34 cm) which was similar to sunflower residues + 100% pyrazosulfuron ethyl (95.97 cm). butachlor recorded plant height of 94.89 cm, next to sunflower residues + 100% pyrazosulfuron ethyl. weedy check recorded the lowest plant height (88.66 cm). all weed control treatments except 2, 4-d amine, and mcpa recorded a significantly higher number of panicles m-2 over the weedy check. the highest number of panicles m-2 (305.00) was recorded from weed free plots by manual weeding which was statistically similar to sunflower residues + 100% pyrazosulfuron ethyl (271.75), butachlor (270.25), bensulfuron methyl + acetachlor (265.00), pretilachlor (263.25) and pendimethalin effect of sunflower residues and herbicide on weed suppression and yield of aman rice 53 (262.75). in general, pre-emergence and early post-emergence herbicides performed better than post-emergence herbicides. the post-emergence herbicides 2, 4-d amine and mcpa produced the lowest no. of panicles m-2 among the herbicides used alone or in combination with sunflower residues and were similar to weedy check. gopinath et al. (2012) observed a higher number of panicles m-2 in butachlor treated plots in rice. all the herbicides except 2, 4-d amine and mcpa resulted in a significantly higher number of grains panicle-1 than the weedy check. of the weed control treatments, the highest number of grains panicle-1 (120.78) was recorded in weed-free treatment, being similar to sunflower residues + 100% pyrazosulfuron ethyl (109.80) and butachlor (108.11). these results are the substantiating with the results of acharya and bhattacharya (2013). the reason for higher plant height, more number of panicles m-2 and grains panicle-1 in the treatments might be due to the fact that there was lower weed-crop competition in terms of dry matter production of weeds as well as good source sink relationship which allowed the crop to absorb the required amount of nutrient, water and sunlight for its growth, production of panicles m-2 and grains panicle-1. all the pre-emergence herbicides, pyrazosulfuron ethyl (early post-emergence) and bispyriback sodium (post-emergence) tested alone, sunflower residues used alone or in combination with pyrazosulfuron ethyl (75 and 50%) produced similar no. of grains panicle-1. weedy check treatment gave the lowest no. of grains panicle-1 (78.85). weedy check treatment produced significantly the highest number of sterile spikelets panicle-1 (29.53). weed-free treatment by hand weeding twice produced the lowest number of sterile spikelets panicle-1 (9.15) which was similar to sunflower residues + 100% pyrazosulfuron ethyl (12.53). 1000-grain weight was not significantly influenced by different weed control treatments. table 4. effect of weed control methods on yield attributes of transplanted aman rice treatments plant height (cm) panicle m-2 (no.) grains panicle-1 (no.) sterile spikelets panicle-1 (no.) 1000-grain weight (g) t1 88.66 d 209.50 d 78.85 d 29.53 a 17.49 t2 101.34 a 305.00 a 120.78 a 9.15 g 19.15 t3 94.15 b-d 262.75 ab 105.42 b 16.47 c-f 18.79 t4 94.40 bc 263.25 ab 105.89 b 16.27 c-f 18.94 t5 94.89 bc 270.25 ab 108.11 ab 14.47 ef 19.01 t6 90.31b-d 252.50 bc 100.25 bc 19.93 bc 18.25 t7 94.47 bc 265.00 ab 106.76 b 15.80 d-f 18.97 t8 93.43b-d 261.75 b 105.38 b 16.80 c-e 18.78 t9 89.43 cd 215.75 cd 85.02 d 21.27 b 18.05 t10 90.19 cd 217.00 cd 87.53 cd 21.13 b 18.22 t11 92.14 b-d 253.25 bc 101.02 b 18.87 b-d 18.46 t12 95.97 ab 271.75 ab 109.80 ab 12.53 fg 19.12 t13 93.32 b-d 260.50 b 101.77 b 17.87 b-e 18.67 t14 92.49 b-d 260.25 b 101.38 b 18.60 b-d 18.66 ls ** ** ** ** ns lsd(0.05) 5.68 42.54 13.24 4.08 cv (%) 3.63 9.95 7.79 13.68 7.58 t1 = weedy check, t2 = weed-free check by hand weeding twice, t3 = pendimethalin, t4 = pretilachlor, t5 = butachlor, t6 = pyrazosulfuron ethyl, t7 = bensulfuron methyl + acetachlor, t8 = bispyriback sodium, t9 = 2, 4-d amine, t10 = mcpa, t11 = sunflower residues, t12 = sunflower residues + 100% pyrazosulfuron ethyl, t13 = sunflower residues + 75% pyrazosulfuron ethyl, t14 = sunflower residues + 50% pyrazosulfuron ethyl, ls = level of significance. figures in a column followed by different letters differ significantly, but with common letter (s) do not differ significantly at 5% level of probability. 54 tanu et al. grain yield, straw yield, harvest index and weed index grain yield was significantly influenced by weed control treatments (table 5). the weed-free plots by hand weeding recorded the highest grain yield (5.14 t ha-1), being comparable to pendimethalin, pretilachlor, butachlor, bensulfuron methyl + acetachlor, and sunflower residues + 100% pyrazosulfuron ethyl. singh et al. (2008) reported that the application of different herbicide treatments gave similar yield to that of weed-free plots. the weedy check treatment produced significantly the lowest grain yield (3.38 t ha-1). among different herbicides, butachlor gave the maximum yield (4.81 t ha-1). bhanurekha et al. (2004) observed that pre-emergence application of butachlor @ 1.5 kg a.i. ha-1 recorded the highest rice grain yield among different herbicides. pre-emergence application of butachlor @ 1.25 kg a.i. ha-1 recorded a significantly higher grain yield of 6084 kg ha-1 in transplanted rice (jayadeva et al., 2009). singh et al. (2005) observed that bensulfuron methyl (londax) at different doses (40 g a.i. ha-1 and 50 g a.i. ha-1) applied alone or as tank mixture with butachlor @ 1000 g a.i. ha-1 increased the grain yield. all these results support our findings of the experiment.2, 4-d amine and mcpa recorded the lowest grain yields (4.01 and 4.11 t ha-1, respectively) among the herbicides treatments. the pre-emergence and early post-emergence herbicides (sole) treated plots, contributed to yield increase ranging from 30.47% to 42.31% with an average value of 38.34% over the weedy check, while the respective increase in yields for 2, 4-d amine and mcpa were only 18.64% and 21.60%, respectively. however, the post emergence herbicide bispyriback sodium recorded a 33.43% yield increase over the weedy check. from the data presented, it might reasonably be argued that early application of herbicides offered early season weed control up to the period of full canopy cover by rice plants, which might also contribute to higher grain yield. application of post-emergence herbicides at 28 dat (as recommended) could not bring the desired benefits as weeds grew luxuriantly and competed with the crop for resources like nutrients, solar radiation, water, and space. moreover, they have shown phytotoxicity symptoms (burning of lower leaves) as shown in table 2 which might have resulted in decreased nutrient uptake and photosynthetic efficiency and thereby ultimately reduced the grain yield. it is noticeable here that grain yields produced by sunflower residue alone and sunflower residue + pyrazosulfuron ethyl at 75 and 50% of recommended dose were comparable to pyrazosulfuron ethyl used alone. in indicates that a reduced rate of pyrazosulfuron ethyl may be feasible for providing satisfactory grain yield when it is applied simultaneously with sunflower residue. these findings are in agreement with alsaadawi and sarbout (2015) who found that a combination of a lower rate of trifluralin and sunflower residues at 6 t ha-1 significantly reduced weed density and weed biomass by 79 and 90%, respectively over control. straw yield followed a similar trend as the grain yield. the harvest index was not significantly affected by weed control treatments. all the weed control methods showed a lower weed index (3.31-21.98%) than the weedy check (34.24%) (table 5). singh et al. (2008) reported that the application of different herbicide treatments recorded a lower weed index. similar results were also reported by bhuiyan et al. (2017). the highest weed index in weedy check was due to the lowest grain yield associated with unchecked weed growth throughout the crop growth period. pre-emergence and early post-emergence herbicides exhibited lower weed index as compared to post-emergence herbicides (2, 4-d amine, and mcpa). however, the lowest weed index was noticed in the application of sunflower residues along with 100% pyrazosulfuron ethyl (3.31%) followed by butachlor (6.42%), as a result of satisfactory control of weeds. effect of sunflower residues and herbicide on weed suppression and yield of aman rice 55 table 5. effect of weed control methods on grain yield, straw yield, harvest index and weed index of transplanted aman rice treatments grain yield (t ha-1) % increase yield over control straw yield (t ha-1) harvest index (%) weed index (%) t1 3.38 d 5.01 e 40.29 34.24 t2 5.14 a 52.07 7.39 a 41.02 0.00 t3 4.71 ab 39.35 6.41 b-d 42.36 8.37 t4 4.72 ab 39.64 6.43 b-d 42.33 8.17 t5 4.81 ab 42.31 6.86 a-c 41.22 6.42 t6 4.41 bc 30.47 5.95 d 42.57 14.20 t7 4.73 ab 39.94 6.60 a-d 41.75 7.98 t8 4.51 bc 33.43 6.36 b-d 41.49 12.26 t9 4.01 c 18.64 5.85 de 40.67 21.98 t10 4.11 c 21.60 5.89 d 41.10 20.04 t11 4.40 bc 30.18 6.12 cd 41.83 14.40 t12 4.97 ab 47.04 6.99 ab 41.56 3.31 t13 4.46 bc 31.95 6.35 b-d 41.26 13.23 t14 4.45 bc 31.66 6.24 b-d 41.63 13.42 ls ** ** ns lsd(0.05) 0.58 0.86 cv (%) 7.74 8.09 5.20 t1 = weedy check, t2 = weed-free check by hand weeding twice, t3 = pendimethalin, t4 = pretilachlor, t5 = butachlor, t6 = pyrazosulfuron ethyl, t7 = bensulfuron methyl + acetachlor, t8 = bispyriback sodium, t9 = 2, 4-d amine, t10 = mcpa, t11 = sunflower residues, t12 = sunflower residues + 100% pyrazosulfuron ethyl, t13 = sunflower residues + 75% pyrazosulfuron ethyl, t14 = sunflower residues + 50% pyrazosulfuron ethyl, ls = level of significance figures in a column followed by different letters differ significantly, but with common letter (s) do not differ significantly at 5% level of probability. economic analysis the acceptance of generated technology by the farmers ultimately depends on the economics involved in the production. the data on a total variable cost, gross return, gross margin and benefit-cost ratio of rice as influenced by weed control treatments are presented in table 6. the maximum variable cost (tk.82235.00 ha-1) was involved in the case of hand weeding. the treatment with sunflower residues (5 t ha-1) + 100% pyrazosulfuron ethyl needed the second highest cost (tk.81345.00 ha-1) followed by sunflower residues (tk.80985.00 ha-1). the lowest cost of production (tk.70985.00 ha-1) was involved in the weedy check. the cost varied due to differences in the cost of weed control methods. weed-free treatment by hand weeding realized the highest gross return of tk.102160.00 ha-1 followed by the application of butachlor (tk.95490.00 ha-1) and bensulfuron methyl + acetachlor (tk.93610.00 ha-1). this can be attributed to better weed control in these treatments resulting in increased grain yield and thereby increased gross return. weedy check realized the lowest (tk. 67480.00 ha-1) gross return. the highest gross margin of tk. 22955.00 ha-1 was earned from the application of butachlor followed by bensulfuron methyl + acetachlor (tk. 21959.00 ha-1). 56 tanu et al. table 6. effect of different weed control methods on the cost of production, gross return, gross margin and benefit-cost ratio of transplanted aman rice treatments total variable cost (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) benefit-cost ratio t1 70985 67480 -3505 t2 82235 102160 19925 1.24 t3 73723 92890 19167 1.26 t4 72135 93100 20965 1.29 t5 72535 95490 22955 1.32 t6 71345 86150 14805 1.21 t7 71651 93610 21959 1.31 t8 71873 89390 17517 1.24 t9 73235 79870 6635 1.09 t10 71973 81650 9677 1.13 t11 80985 87040 6055 1.07 t12 81345 98470 17125 1.21 t13 81255 88520 7265 1.09 t14 81165 88130 6965 1.09 t1 = weedy check, t2 = weed-free check by hand weeding twice, t3 = pendimethalin, t4 = pretilachlor, t5 = butachlor, t6 = pyrazosulfuron ethyl, t7 = bensulfuron methyl + acetachlor, t8 = bispyriback sodium, t9 = 2, 4-d amine, t10 = mcpa, t11 = sunflower residues, t12 = sunflower residues + 100% pyrazosulfuron ethyl, t13 = sunflower residues + 75% pyrazosulfuron ethyl, t14 = sunflower residues + 50% pyrazosulfuron ethyl note: price of input and output urea = 20.00 (tk. kg-1), tsp = 28.00 (tk. kg-1), mop = 20.00 (tk. kg-1), gypsum = 20.00 (tk. kg-1), zinc sulphate = 180.00 (tk. kg-1), labor = 450.00 (tk. day-1), rice seed = 22.00 (tk. kg-1), pendimethalin = 1095 tk. l-1, pretilachlor = 1150 tk. l-1, butachlor = 62.00 (tk. kg-1), pyrazosulfuron ethyl = 60.00 (tk. 25 g-1), bensulfuran methyl+ acetachlor = 45.00 (tk. 50 g-1), bispyribac na = 120.00 (tk.20 g-1), 2,4-d amine = 100.00 (100 ml-1), mcpa = 100.00 (100 ml-1). however, the gross margin recorded in butachlor was around 15.21% higher than weed free treatment. higher gross margin was the result of higher grain and straw yields due to better control of weeds throughout the crop growth. the highest gross margin and benefit-cost ratio were recorded in bensulfuronmethyl as reported by saha and rao (2009). a negative gross margin was recorded in the weedy check (-tk. 3505 ha-1). the highest bcr of 1.32 was realized with the application of butachlor which was close to bensulfuron methyl + acetachlor (1.31). this was due to the lower cost of herbicides and no labor use for weeding. hand weeding recorded a lower bcr (1.24) which could be due to the higher cost involved in engaging human labor for weeding. the lowest bcr was due to lowest grain and straw yields caused by heavy weed infestation. hasanuzzaman et al. (2008) and singh et al. (2017) reported that herbicidal treatments were more profitable than hand weeding. maiti and mukharjee (2003) also obtained lower gross margin and bcr in farmers’ practice of hand weeding. among the weed control treatments, although hand weeding rendered effective weed control and highest grain yield, preemergence application of butachlor rendered the highest gross margin and benefit cost ratio of transplanted aman rice. the use of butachlor reduces the drudgery on labors and saves scarce and costly labor thus resulting in a lower cost of cultivation. effect of sunflower residues and herbicide on weed suppression and yield of aman rice 57 conclusion from this study, it is observed that the use of butachlorand bensulfuron methyl+ acetachlor were most profitable among different weed control methods. the use of herbicide may be an alternative in controlling weeds more easily and cheaply when there is a labor crisis. it may therefore be concluded that the herbicide butachlorand bensulfuron methyl+ acetachlor can be used as an alternative for greater profitability when labor is a limiting factor in producing transplanted aman rice. application of sunflower residues along with pyrazosulfuron ethyl is another option for an eco-friendly approach in minimizing reliance upon synthetic herbicides in sustainable agriculture. references acharya, s.s. and s.p. bhattacharya. 2013. comparative efficacy of pyrazosulfuron ethyl and bentazon with acetamides for weed control in transplanted boro rice (oryza sativa) in the lower gangetic plain zone of west bengal, india. intl. j. bio-resour. stress mng. 4(4): 506509. akbar,n., e. ullahand k.m.a. jabran. 2011.weed management improves yield and quality of direct seeded rice. asian j. crop sci. 5(6): 688-694. alsaadawi, i.s. and a.k. sarbout. 2015. reducing herbicide rate in combination with allelopathic sunflower residues for weed control in cowpea. j. allelochem. interact. 2(1): 9-16. alsaadawi, i.s.,a. khaliq, a.a. al-temimi and a. matloob. 2011. integration of sunflower residues with a pre-plant herbicide enhances weed suppression in broad bean. planta daninha vicosa-mg. 29(4): 849-859. angiras, n.n. and s. kumar. 2005. efficacy of pyrazosulfuron ethyl against weeds in rice nursery under mid hill conditions of himachal pradesh. indian j. weed sci. 25(3&4): 202-204. barua, i.c., n. borah, j. deka and n.c. deka. 2008. weed flora of transplanted autumn rice of barak valley, assam. proceedings, biennial weed science conference, 27-28 february, rajendra agricultural university, pusa, bihar, india, p.178. bhanurekha, k., p. kavitha and r.m. shrinivasa. 2004. performance of herbicides for weed control in transplanted rice (oryza sativa l.). the andhra agric. j. 51(1 & 2): 1-4. bhuiyan, m.k.a., m.m. mahbub and m.z.i. baki. 2018. sensitivity of annual weeds against metolachlor + bensulfuron methyl herbicide in transplanted rice. bangladesh agron. j. 21(1): 61-70. bhuiyan, m.k.a., m.m. mahbub, m.z.i. baki and l. nahar. 2017. sensitivity of annual weeds against sulfentrazone 48 sc herbicide in rice cultivation. bangladesh rice j. 21(1): 61-70. brri (bangladesh rice research institute). 2008. annual report for 2007. bangladesh rice res. inst. joydebpur, gazipur. pp.28-35. chandel, s.r.s. 1984. a hand book of agricultural statistics, 7th ed., pp.358-359. gomez, k.a. and a.a. gomez.1984. statistical procedure for agriculture research. 2nd edition. john willey and sons, new york. p.680. gopinath, k.a., b.l. mina, k.p. singh and k.c. nataraja. 2012. integrated weed management in direct seeded rainfed rice (oryza sativa). indian j. agron. 57(3): 245-249. hasanuzzaman, m., m.o. islam and m.s. bapari. 2008. efficacy of different herbicides over manual weeding in controlling weeds in transplanted rice. australian j. crop sci. 2(1): 1824. irri (international rice research institute). 1999. world rice statistics. 1997-98. intl. rice res. inst. manila, philippines. p.233. 58 tanu et al. jabran, k., g. mahajan, v. sardana and b.s.chauhan. 2015. allelopathy for weed control in agricultural systems. crop prot. 72: 57-65. jayadeva, h.m., s.t. bhairappanavar, p.r. somashekharappa and b.r. rangaswamy. 2009. efficacy of azimsulfuron for weed control in transplanted rice. indian j. weed sci. 41(3&4): 172-175. khanh, t.d., m.i. chung, t.d. xuan and s. tawata. 2005. the exploitation of crop allelopathy in sustainable agriculture. j. agron. crop sci. 191: 172-184. maity, s.k. and p.k. mukherjee. 2003. integrated weed management practices in dry direct seeded summer rice. indian j. agric. sci. 79: 976-979. misra, m. and m. misra. 1997. estimation of ipm index in jute: a new approach. indian j. weed sci. 29: 39-42. raj, r., a. kumar, v. kumar, c.b. singhand u.c. pandey. 2016. herbicide options for controlling weeds in transplanted rice (oryza sativa) under north eastern plains zone indian j. agron. 61(2): 197-203. rawat, l.s., r.k. maikhuri, y.m. bahuguna, n.k. jha and p.c. phondani. 2017. sunflower allelopathy for weed control in agriculture system. j. crop sci. biotech. 20(1): 45-60. saha, s. and k.s. rao. 2009. efficacy of sulfonylurea herbicides for broad spectrum weed control in wet direct sown summer rice. oryza. 46(2): 116-119. saif, h.b., m.n. bari, m.r. islam and m.a. rahman. 2016. allelopathic potential of sunflower extract on weed control and wheat yield under subtropical conditions. intl. j. appl. sci. 2(40): 44-48. shibayama, h. 1980. morphological responses of rice plants to mcpa. japan agril. res. quar. 14(1): 1-3. singh, s., j.k. ladha, g.k. gupta, l. bhusan and a.n. rao. 2008. weed management in aerobic rice systems under varying establishment methods. crop prot. 27: 660-671. singh, t., b.s. satapathy, p. goautam, b. lal, u. kumar, k. saikia and k.b. pun. 2017. comparative efficacy of herbicides in weed control and enhancement of productivity and profitability of rice. expt. agric. 1-9. singh, v.p., g. singh and m. singh. 2005. effect of bensulfuron-methyl (londax 60 df) on sedges and non-grassy weeds in transplanted rice. indian j. weed sci. 37(1&2): 40-44. zahan, t., m.m. rahman, a. hashem, m. begum, r.w. bell and m.e. haque. 2014. weed control efficacy of herbicides in unpuddled transplanted aman (summer) rice. in: proc. conservation agriculture for smallholders in asia and africa. mymensingh, bangladesh. december 7-11. pp.110-111. microsoft word 14 bangladesh agron. j. 2017, 20(2): 123-133 effect of fertilizer and manure on the movement ofeffect of fertilizer and manure on the movement ofeffect of fertilizer and manure on the movement ofeffect of fertilizer and manure on the movement of npks in npks in npks in npks in rice rice rice rice soilsoilsoilsoilssss ofofofof madhupur tract and meghnamadhupur tract and meghnamadhupur tract and meghnamadhupur tract and meghna river floodplainriver floodplainriver floodplainriver floodplain m. a. khanm. a. khanm. a. khanm. a. khan1111****, m. a. islam, m. a. islam, m. a. islam, m. a. islam1111, a. s. m. f. bari, a. s. m. f. bari, a. s. m. f. bari, a. s. m. f. bari1111 and and and and s. akters. akters. akters. akter2222 1department of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2biotechnology division, bangladesh institute of nuclear agriculture, mymensingh-2202, bangladesh *corresponding author, e-mail: makhan_sau@ymail.com (receivedreceivedreceivedreceived:::: 21 december 2017, accepted:accepted:accepted:accepted: 29 january 2018) keywordskeywordskeywordskeywords: nutrient leaching, yield, nutrient accumulation, soil diversity abstractabstractabstractabstract the experiment was conducted in a net house of sher-e-bangla agricultural university,(23°35'n latitude and 90°35'e longitude) dhaka, bangladesh during november may to study the effect of fertilizer and manure on the yield of boro rice and movement of nutrients through undisturbed soil columns. the experiment consists of 2 factors, i.e. soils and fertilizer plus manure. two soils (s1= sau soil and s2= sonargaon soil) with 4 levels of fertilizer plus manure, as t0: control, t1: 100% n120p20k45s20 (recommended dose), t2: 50% npks + 5 t ha−1 cowdung, t3: 50% npks + 2.1 t ha−1 poultry manure were imposed during boro (winter) season. boro rice (brri dhan29) was grown in the soil cores, and fertilizer and manure treatments were applied to the soils. higher and statistically similar grain yields of boro rice were found from t1, t2, and t3 fertilizer treatments. the highest grain yield was found where 50% npks + 5 t ha-1 cowdung were used in the sonargaon soil. higher grain n, p and k concentrations were obtained in the treatment combination where fertilizer plus manure were applied in two soils. higher leachate n, p and k concentrations were found in 100% chemical fertilizer treatment. the n leaching increased up to 45 dat and then declined while the p and k leaching increased up to 35 dat and then decreased. higher ph values were found in the 10-20cm depth of post-harvest soils in comparison to 0-10 cm. the higher ph values were found in soils where 50% npks + 2.1 t ha−1 poultry manure applied. the level of p more increased in the depths of 0-10 cm of sau soil where fertilizer or fertilizer plus manure were applied and the p concentrations more increased in the depth of 10-20 cm where fertilizer plus manure were applied in sau soil. the level of s more increased in the depths of 0-10 cm and 10-20 cm of s2t2 and s2t3 treatment combination where fertilizer plus manure applied in sonargaon soil. similar levels of n and k concentrations were observed in the initial and post-harvest soils. introductionintroductionintroductionintroduction the soil fertility depletion is a major problem to higher crop production in bangladesh. the increasing cropping intensity has resulted in a great exhaustion of nutrients in soils. rice-rice cropping system is the most important cropping pattern in bangladesh. among the three types of rice, boro rice covers about 56.66% of total rice area and it contributes to 43.24% of the total rice production in the country (bbs, 2008). the application of fertilizer and manure play an important role in the production of dry season winter rice (locally called, boro rice). it will, therefore, be necessary to place greater emphasis on strategic research to increase the 124 khan et al. efficiency of applied nutrients through integration with organic manures, which will help in accomplishing twin objectives of sustaining soil health and ensuring food security and environmental protection. application of manure and fertilizer affects the nutrient movement in soil. the available nutrient moves downward with percolated water. the bioavailability and movement of nutrients in the soil are dependent on some factors including the source and concentration of the nutrient, soil properties such as clay content, ph and redox conditions, ions and type and amount of organic matter. the mobility of nutrient through the percolated water was evaluated by this experiment and the effect of manure and fertilizer on the growth and yield of boro rice were evaluated. organic matter decomposition and nutrients mineralization are greatly affected by the soil moisture level (guntinas et al., 2012). anaerobic condition in paddy soil leads to mobilization of some nutrients and thus affects nutrients bio availability to rice plants (fageria et al., 2011). the transport of nitrogen (n), phosphorus (p), potassium (k) and sulfur (s) in soil is governed by the difference of soil and the variation of added fertilizer. application of chemical fertilizers with farmyard manure increased n, p and k uptake by rice plants and increased grain yield of rice (yang et al., 2004). the mobility of n, p, k and s in soil is still not thoroughly understood. there is the possibility of preferential flow of k in the undisturbed soil cores due to lack of k sorption (jalali and rowell, 2009). repeated application of organic forms of p could lead to significant leaching of p to ground water (anderson and magdoff, 2005). little work has been done on the fate of applied fertilizer and manure during rice culture through undisturbed soil columns. to increase the efficiency of manure and fertilizer in rice cultivation, it is necessary to identify the suitable level and type of manure and fertilizer. the fate of added fertilizer in the soil column and estimation of nutrient leaching is important for plant nutrition and soil fertility. soil is a heterogeneous system, and the study was undertaken to understand the effect of manure and fertilizer on yield and leaching loss of nutrients through undisturbed soil columns with rice culture. materials and methodsmaterials and methodsmaterials and methodsmaterials and methods an experiment was carried out in a net house of sher-e-bangla agricultural university (23°35'n latitude and 90°35'e longitude) during july 2011 to may 2012 to evaluate the movement of nutrient in undisturbed soil columns with rice culture. boro (winter) rice was grown in the core during december 2011 to may 2012 and transplanted aman (t. aman) rice was grown in the same cores during july 2011 to november, 2011. the climate of the experimental area is characterized by a scanty rainfall associated with moderately low temperature in the rabi season (october to march, 2011-2012). two different types of soils were collected in pvc pipes from the sau farm and sonargaon, narayanganj during july, 2011. twenty four (2 soils × 4 fertilizer treatment × 3 replication) undisturbed soil cores (25 cm diameter and 40 cm length) were collected in pvc pipes. initial soil samples were collected from each site and analyzed for physico-chemical properties. the soil was taken from a rice cultivated farm with a homogenous soil. the polyvinyl chloride (pvc) pipe was pushed to the soil by creating pressure inside pipe wall and by adding water to the soil. the soil cores were transferred to the net house and processed for setting on the plastic container. filter paper (whatman no. 1), glass wool and a 4-cm layer of acid-washed silica sand (sieved to obtain a 1–2 mm particle diameter) were placed at the bottom of the plastic container that served as the base for the pvc soil core. two holes in the plastic base 125 effect of fertilizer and manure on the movement of npks in rice 40cm40cm40cm40cm soil coresoil coresoil coresoil core rice plantrice plantrice plantrice plant filter paperfilter paperfilter paperfilter paper coarse sand layercoarse sand layercoarse sand layercoarse sand layer glassglassglassglass--- woolwoolwoolwool plastic pipeplastic pipeplastic pipeplastic pipe glassglassglassglass----tttt corkcorkcorkcork leachateleachateleachateleachate were connected using polypropylene tubes and a t tube to a conical flask that was used to collect column leachate (fig. 1). fig. 1. leachate collection from undisturbed soil core with fertilizer and manure application in boro rice. two soils (soil-1: sau soil, soil-2: sonargaon soil) and four fertilizer treatments (t0: control, t1: recommended dose of fertilizer (n120p20k45s20), t2: 50% npks + 5 ton ha-1 cowdung, t3:50% npks + 2.1 ton ha-1 poultry manure) were used for rice cultivation in the pvc core. the differences between sau and sonargaon soils were in texture (silt loam and silty clay loam), ph (6.4 and 7.3), extractable k (0.05 and 0.06 cmolkg-1), p (19.85 and 12.00 ppm) s(14.40 and 16.00 ppm) and total n(0.06 and 0.07%). sonargaon soil had higher organic carbon (1.01%) than sau soil (0.69%). the treatment wise required amounts of manures and n, p, k and s fertilizers per core were applied by considering the soil weight of 0-15 cm depth. poultry manure had elevated n (2.2%), p (1.99%), k (0.82%) and s (0.29%) in comparison to the n (1.46%) p (0.29%) k (0.74%) and s (0.24%) of cowdung. full amounts of manure, tsp, mp and gypsum were applied at final land preparation before transplanting of rice seedlings. urea was applied in 3 equal splits: one third was applied at basal before transplanting, one third at active tillering stage (30 dat) and the remaining one third was applied at five days before panicle initiation stage. 126 khan et al. rice var. brri dhan29 was used as the test crop in this experiment which is recommended for boro season. the experimental design was randomized complete block design (rcbd) with two factors and three replicates for each treatment. the distance maintained between core to core and row to row were 40 cm and 1m respectively. thirty days old boro seedlings were transplanted on the second week of december, 2011. two seedlings for one hill were transplanted in the core. traditional irrigation (2-3 cm continuous flooding) was applied during the growing period of boro rice crop. intercultural operations and plant protection measures were done to ensure normal growth of the crop. leachate samples were collected at 25, 35, 45, 55, 65 and 75 days after transplantation of boro rice and analyzed for n, p, k and s by using standard analytical methods. the boro crop was harvested at full maturity when 80-90% of the grains were turned into straw colored on may, 2012. the crop was cut at the ground level. after harvest, the rice yield parameters and yield were recorded. soil and leachate analysissoil and leachate analysissoil and leachate analysissoil and leachate analysis soil samples were analyzed for both physical and chemical characteristics viz. texture, ph, total n and available p, k, and s contents. mechanical analysis of soil was done by hydrometer method (bouyoucos, 1926) and the textural class was determined. soil ph was measured with the help of a glass electrode ph meter (jackson, 1962). the soil organic carbon was determined by wet oxidation method (walkley and black, 1935). total soil n concentrations were determined by the micro kjeldahl method (page et al., 1982). available p was determined from the soil with 0.5 m nahco3 solutions, ph 8.5 (olsen et al., 1954). exchangeable k was determined by 1n nh4oac (ph 7) extraction method. available s content was determined by extracting the soil with cacl2 (0.15%) solution as described by (page et al., 1982). the leachate samples were analyzed for n, p, k and s by using similar methods. the data obtained for different parameters were statistically analyzed to find out the significant difference of different treatments on yield and yield contributing characters. the mean values of all the characters were calculated and analysis of variance was performed by the ‘f’ (variance ratio) test. the significance of the difference among the treatment means was estimated by the duncan’s multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). results and discussionresults and discussionresults and discussionresults and discussion effect of soileffect of soileffect of soileffect of soils, fertilizers, fertilizers, fertilizers, fertilizer and manureand manureand manureand manure on the yield parameters on the yield parameters on the yield parameters on the yield parameters and yield ofand yield ofand yield ofand yield of boroboroboroboro ricericericerice the effects of soil, fertilizer and manure on the yield parameters and yield of rice are presented in table 1. the plant height, panicle length and filled grains panicle-1, grain and straw yields were not significantly influenced by the variation of soils. sonargaon soil showed higher plant height, panicle length and number of filled grains panicle-1. the higher grain (29.67 g/core) and straw yield (34.13 g/core) were obtained in sonargaon soil and lower in sau soil (table 1). plant height, panicle length, filled grains panicle-1, 1000 grain weight and grain yield were significantly affected by fertilizer and manure treatments. among the different fertilizer doses, t3 (50% npks + 2.1 t poultry manure) showed the highest plant height (79.95 cm), which was closely followed by t1, (rdcf) t2 (50% npks + 5 t ha-1 cowdung) and lowest plant height (64.18 cm) was observed in the t0 treatment. higher and statistically similar number of filled grains panicle-1 and 1000 grain weight were noticed in the t1, t2 and t3 fertilizer treatments. the higher straw yield (34.90 g/core) was recorded in t1 ((n120p20k45s20) treatment.) the 127 effect of fertilizer and manure on the movement of npks in rice grain yield was significantly increased due to the application of manure and chemical fertilizers (rahman et al., 2009). table 1. effects of soil, fertilizer and soil ×fertilizer on the yield parameters and yield of boro rice treatments plant height (cm) panicle length (cm) no. of filled grain/ panicle 1000 grain wt. (g) straw yield (g/core) grain yield (g/core) effect of soil s1 70.27 21.16 83.01 20.23 28.05 24.58 s2 73.22 21.94 95.34 20.52 34.13 29.67 se (±) ns ns ns ns ns ns effect of fertilizer and manure t0 64.18 c 20.57 76.00 b 20.12 b 24.95 20.22 b t1 73.73 ab 22.26 100.00 a 20.75 a 34.90 30.67 a t2 69.12 bc 21.55 92.00 ab 20.27 ab 31.80 29.27 ab t3 79.95 a 21.84 89.00 ab 20.37 ab 32.72 28.33 ab se (±) 1.629 ns 4.306 0.116 ns 2.1260 interaction effect of fertilizer and soil s1t0 61.52 20.72 73.00 20.30 b 23.97 19.53 s1t1 73.48 21.86 95.00 20.43 ab 32.40 28.03 s1t2 69.12 21.22 76.00 20.13 b 28.23 24.23 s3t3 76.96 20.86 88.00 20.07 b 27.60 26.50 s2t0 66.84 20.42 79.00 19.93 b 25.93 20.90 s2t1 73.97 22.66 105.00 21.07 a 37.40 33.30 s2t2 69.13 21.88 108.00 20.40 ab 35.37 34.30 s2t3 82.94 22.82 90.00 20.67 ab 37.83 30.17 se (±) ns ns ns 0.1633 ns ns in a column figure(s) having similar letter do not differ significantly at 5% level of significance as per dmrt. different doses of fertilizers showed significant variations in respect of grain yield. the application of fertilizers and manure had a positive effect on the grain yield of boro rice. among the different doses of fertilizers, t1 showed the highest grain yield/core (30.67 g core-1) which was statistically similar with the t2 and t3 treatment. on the contrary, the lowest grain yield/core (20.22 g core-1) was observed with t0 where no fertilizer was applied. application of inorganic fertilizer and manure increased the rice yield in the findings of (miah et al., 2006; reddy et al. 2005; xu et al., 2008). the combined application of different doses of fertilizer and soils had an insignificant variation on the plant height, panicle length, filled grains panicle-1, grain and straw yields of rice (table 1). the higher plant height, panicle length and straw yields were recorded in s2t3 (sonargaon soil + 50% npks + 2.1 t ha-1 poultry manure) treatment. the highest number of filled grains per panicle of rice (108.00) was recorded with the treatment combination s2t2 (sonargaon soil + 50% npks + 5 t cowdung/ha). the combined effect of different doses of fertilizer and soils on the straw yield of rice was insignificant. the higher straw yield (37.83 g core-1) was recorded with the treatment combination s2t3 (sonargaon soils +50% npks + 128 khan et al. 2.1 t poultry manure ha-1) and the lowest straw yield (23.97 g core-1) was found in s1t0 (soils sau+ control treatment) treatment combination. the highest grain yield was recorded in (34.30 g core-1) s2t2 which was similar to s2t1 and s2t3 treatment combination. the results indicate that 50% nutrient from inorganic fertilizer and 50% from manure can be used for boro rice cultivation. npks concentration in grainnpks concentration in grainnpks concentration in grainnpks concentration in grain effect of soilseffect of soilseffect of soilseffect of soils, fertilizer and manure, fertilizer and manure, fertilizer and manure, fertilizer and manure on non non non n, , , , pppp, , , , kkkk and and and and s concentration ins concentration ins concentration ins concentration in boro rice grain boro rice grain boro rice grain boro rice grain the grain n, p and k concentrations were not significantly affected by different soils. similar grain n p and k concentrations were found in sau and sonargaon soils. significant variation was observed in grain s concentration of rice grown in two different soils. between these two soils, s2 showed the higher (0.117%) s concentration compared to grain s (0.103%) of s1 soil. table 2. effects of soil, fertilizer and soil ×fertilizer on the n, p, k and s concentration of boro rice grain treatments grain nutrient concentration (%) n p k s effect of soil s1 1.155 0.248 0.269 0.103 a s2 1.153 0.242 0.282 0.117 b se (±) ns ns ns 0.002 effect of fertilizer and manure t0 1.050 0.223 0.231 d 0.095 d t1 1.178 0.248 0.286 c 0.125 a t2 1.205 0.261 0.296 a 0.105 c t3 1.183 0.249 0.291 b 0.115 b se (±) ns ns 0.0073 0.0041 interaction effect of soil and fertilizer s1t0 0.980 0.226 0.240 0.086 s1t1 1.210 0.258 0.276 0.112 s1t2 1.240 0.272 0.283 0.102 s1t3 1.190 0.237 0.279 0.112 s2t0 1.120 0.220 0.221 0.104 s2t1 1.147 0.238 0.296 0.139 s2t2 1.170 0.251 0.309 0.108 s2t3 1.177 0.261 0.303 0.117 se (±) ns ns ns ns cv (%) 10.49 13.61 6.48 9.18 in a column figure(s) having similar letter do not differ significantly at 5% level of significance as per dmrt. nitrogen and phosphorus concentrations in grain of boro rice showed statistically insignificant variation due to the application of different doses of fertilizers and manure (table 2). the similar levels of grain n concentrations were recorded in all the treatments except control. the higher n (1.205%) and p (0.261%) concentrations were recorded from t2 (50% npks + 5 t cowdung ha-1) which was closely followed by t3 (50% npks + 2.1 t poultry manure ha-1) effect of fertilizer and manure on the movement of npks treatments and the lowest level was found in the grain of t n and p content in rice grain due to the application of organic manure and fertilizers have been reported by investigators (hoque, 1999). potassium and sulphur (s) concentrations in grain of rice showed statistically significant variation due to the application of different doses of fertilizers and manure. the highest k concentration in grain (0.296%) was recorded in t increased due to combined application of organic manure and chemical fertilizers. the higher (0.125%) s concentration in grain was recorded from t followed (0.115%) by t3. the lower grain k (0.231%) and s (0.095%) concentrations we found from t0 treatment. the combined effect of different doses of fertilizer and soils on n, p, k and s concentrations in rice grain was insignificant (table 2). (0.272%) were recorded with the treatment combination s ha−1 cowdung). the higher k (0.309%) treatment combination s2t2 (sonargaon soil + 50% npks + 5 grain n, p k and s concentrations were effect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate n growing periodgrowing periodgrowing periodgrowing period the nutrient concentrations in the leachate were not significantly influenced while significantly affected by fertilizer treatments. no significant effect on leachate n, p, k and s concentrations in the leachate maximum dates of sampling. the applied fertilizer and manure resulted concentrations in the leachate. higher n concentrations were found in the leachate of 100% recommended a dose of chemical fertilizer (t control treatment (fig. 2). fig. 2. effect of fertilizer and manure on n and k conc. in the leachate of different dates of boro rice growing period. dat the n leaching increased up to 45 dat and concentration (5.36 ppm) was found in t treatments, higher concentrations of k were found in the leachate of 100% chemical fertilizer treatment compared to other fertilizer treatments (fig. 2). the highest k concentration (5.24 ppm) in the leachate was found at 35 dat with t 129 effect of fertilizer and manure on the movement of npks in rice the lowest level was found in the grain of t0 treatment. a significant increase in n and p content in rice grain due to the application of organic manure and fertilizers have been 1999). rations in grain of rice showed statistically significant variation due to the application of different doses of fertilizers and manure. the highest k concentration in grain (0.296%) was recorded in t2 treatment. potassium content in grain was e to combined application of organic manure and chemical fertilizers. the higher (0.125%) s concentration in grain was recorded from t1 as n120p20k45s20 which was closely . the lower grain k (0.231%) and s (0.095%) concentrations we effect of different doses of fertilizer and soils on n, p, k and s concentrations in ). the higher grain n (1.240%) and p concentrations (0.272%) were recorded with the treatment combination s1t2 (sau soil +50% npks + 5 the higher k (0.309%) and s (0.139%) concentrations were recorded with the (sonargaon soil + 50% npks + 5 t ha−1 cowdung). the lower were found in s1t0 and s1t0 treatment combination. effect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate neffect of fertilizers and manure on the leachate n, p, p, p, p,,,, kkkk and sand sand sand s concentrations during boro rice concentrations during boro rice concentrations during boro rice concentrations during boro rice leachate were not significantly influenced by different soils while significantly affected by fertilizer treatments. the combined effect of soil and fertilizer had no significant effect on leachate n, p, k and s concentrations in the leachate samples of the applied fertilizer and manure resulted in higher npks higher n concentrations were found in the leachate of 100% dose of chemical fertilizer (t1) and lowest concentration was observed in the 2. effect of fertilizer and manure on n and k conc. in the leachate of different dates of . dat (days after transplanting). the n leaching increased up to 45 dat and after that decreased gradually and highest concentration (5.36 ppm) was found in t1 treatment at 45 dat. among the fertilizer treatments, higher concentrations of k were found in the leachate of 100% chemical fertilizer er treatments (fig. 2). the highest k concentration (5.24 ppm) in the leachate was found at 35 dat with t1 treatment and lowest k concentrations 129 treatment. a significant increase in n and p content in rice grain due to the application of organic manure and fertilizers have been rations in grain of rice showed statistically significant variation due to the application of different doses of fertilizers and manure. the highest k treatment. potassium content in grain was e to combined application of organic manure and chemical fertilizers. the higher which was closely . the lower grain k (0.231%) and s (0.095%) concentrations were effect of different doses of fertilizer and soils on n, p, k and s concentrations in p concentrations (sau soil +50% npks + 5 t recorded with the the lower concentrations during boro rice concentrations during boro rice concentrations during boro rice concentrations during boro rice different soils effect of soil and fertilizer had samples of higher npks higher n concentrations were found in the leachate of 100% tion was observed in the 2. effect of fertilizer and manure on n and k conc. in the leachate of different dates of decreased gradually and highest dat. among the fertilizer treatments, higher concentrations of k were found in the leachate of 100% chemical fertilizer er treatments (fig. 2). the highest k concentration (5.24 treatment and lowest k concentrations 130 khan et al. were found from the control. chemical fertilizer was more leachable from the soil solution than organic plus inorganic fertilizer treatments due to adsorption to organic and inorganic colloids and slow release of nutrient from manure. the higher k concentrations were found in the leachate of 35 dat and then almost similar trend was observed. when fertilizer was app initially more leachable k was present in the leachate firstly, and after 35 days soluble k was fixed on the soil colloidal surface. the fertilizer application did not affect the leachate leachate-p concentrations were relatively low with all soils, fertilizer treatments and different time of sampling. higher leachate p concentrations were found in the t where fertilizer and manure were applied (fig.3). dat and then decreased. among the fertilizer treatments, higher levels of s concentrations were recorded in the leachate of two combined tre were used with 50% chemical fertilizer (fig. obtained at 55 dat from the t3 treatment wh manure ha-1 were applied. the lowest s concentration (0. control treatment. fig. 3. effect of fertilizer and manure on n and k conc. in the leachate of different dates of boro rice growing period effect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in post between two soils, sonargaon soil showed higher ph (7 depth of post-harvest soil. almost similar soil ph values were f harvest soils of sau and sonargaon. (0.08%) at 0-10 cm depth compared to in the depth of (0-10) cm and (10 concentrations varied significantly with soil and h sau soil than sonargaon soil. in both the soils levels of p decreased with increasing soil depth may be due to more applied p fixation with the top soil (26.77 ppm) was found at a depth of 0 depth of 10-20 cm of sonargaon soil. the sau soil compared to sonargaon soil 0-10 cm and 10-20 cm of each soil soils. available sulfur in the post-harvest soils and higher s concentrations were found in the sonargaon soil compared to sau soil. lower and similar levels of s concentrat 10-20 cm depths of sau soil but the level of s decreased with increasing depth of sonargaon were found from the control. chemical fertilizer was more leachable from the soil solution than organic fertilizer treatments due to adsorption to organic and inorganic colloids and slow release of nutrient from manure. the higher k concentrations were found in the leachate of 35 dat and then almost similar trend was observed. when fertilizer was app initially more leachable k was present in the leachate firstly, and after 35 days soluble k was he fertilizer application did not affect the leachate-p concentrations significantly and the s were relatively low with all soils, fertilizer treatments and different higher leachate p concentrations were found in the t1, t2 and t3 treatments fertilizer and manure were applied (fig.3). the leachate p concentration increased at dat and then decreased. among the fertilizer treatments, higher levels of s concentrations were recorded in the leachate of two combined treatment where cowdung or poultry manure were used with 50% chemical fertilizer (fig.3). the highest concentration of 4.21 ppm s was treatment where 50% inorganic fertilizer and 2.1 ton poultry d. the lowest s concentration (0.83 ppm) was obtained from the effect of fertilizer and manure on n and k conc. in the leachate of different dates of effect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in posteffect of soil, fertilizer and manure on ph and npks concentrations in post----harvest soilharvest soilharvest soilharvest soil l showed higher ph (7.3) than sau soil ph (6.8) at 0-10 harvest soil. almost similar soil ph values were found at 10-20 cm depth of post harvest soils of sau and sonargaon. sau soil showed the higher total n concentration cm depth compared to the soil of 10-20 cm depth. similar n-conc. was found 10-20) cm of sonargaon soil. the available p and k significantly with soil and higher levels of p concentrations were found both the soils levels of p decreased with increasing soil depth p fixation with the top soils. the highest available p concentration depth of 0-10 cm of sau soil and lowest (15.02 ppm) in the . the higher concentrations of available k were found in compared to sonargaon soil and similar levels of k were obtained in the depth of may be due to higher mobility of applied k in both the harvest soil showed statistically significant variations in different and higher s concentrations were found in the sonargaon soil in both the depths lower and similar levels of s concentrations were found at 0-10 and but the level of s decreased with increasing depth of sonargaon were found from the control. chemical fertilizer was more leachable from the soil solution than organic fertilizer treatments due to adsorption to organic and inorganic colloids and slow release of nutrient from manure. the higher k concentrations were found in the leachate of 35 dat and then almost similar trend was observed. when fertilizer was applied initially more leachable k was present in the leachate firstly, and after 35 days soluble k was and the s were relatively low with all soils, fertilizer treatments and different treatments p concentration increased at 35 dat and then decreased. among the fertilizer treatments, higher levels of s concentrations poultry manure ppm s was poultry ppm) was obtained from the effect of fertilizer and manure on n and k conc. in the leachate of different dates of 10 cm cm depth of postwed the higher total n concentration conc. was found and k igher levels of p concentrations were found in both the soils levels of p decreased with increasing soil depth concentration in the the higher concentrations of available k were found in and similar levels of k were obtained in the depth of may be due to higher mobility of applied k in both the different in both the depths 10 and but the level of s decreased with increasing depth of sonargaon 131 effect of fertilizer and manure on the movement of npks in rice soil (table 3). the depth wise observed variability of s may be the cause of the difference of physico-chemical properties of soil. the ph of 0-10 cm depth of post-harvest soil showed insignificant variation due to the application of different doses of fertilizers (table 3). the ph of 10-20 cm depth of post-harvest soil was significantly affected by different soils. almost similar soil ph was found at 10-20 cm depth of post-harvest soil of sau and sonargaon soils. total n, available p, k and s concentrations in post-harvest soil showed statistically significant differences due to the application of different manure and fertilizer in rice. the level of total n in post-harvest soil slightly increased due to combined application of fertilizer and manure. the slightly higher (0.09 and 0.08 %) total n concentrations were found in the post-harvest soils of (0-10) cm and (10-20) cm depths where t2 (50% npks + 5 ton cowdung/ha) treatment was applied during t.aman and boro season. table 3. effects of soil, fertilizer and soil × fertilizer on the ph, n, p, k and s content in postharvest soil treatments soil ph total n (%) available p (ppm) available k (ppm) available s (ppm) (0-10) cm (10-20) cm (0-10) cm (10-20) cm (0-10) cm (10-20) cm (0-10) cm (10-20) cm (0-10) cm (10-20) cm effect of soil s1 6.8 a 7.2 a 0.08a 0.07 26.77a 22.63a 17.79a 17.37a 19.82a 18.79a s2 7.3 b 7.6 b 0.07b 0.07 18.52b 15.02b 12.13b 12.29b 29.36b 24.42b se (±) 0.042 0.015 0.001 ns 1.4383 0.751 0.833 0.712 0.790 0.796 effect of fertilizer and manure t0 7.2 7.2 c 0.06d 0.06c 14.92b 13.87c 9.75b 10.58c 13.43c 13.88c t1 6.9 7.5 a 0.07c 0.07b 24.66a 16.74bc 16.25a 13.92bc 25.78b 20.94b t2 7.1 7.4 b 0.09a 0.08a 27.19a 23.56a 14.58ab 16.33ab 25.37b 25.05ab t3 7.1 7.5 ab 0.08b 0.07b 23.87ab 21.15ab 19.25a 18.50a 33.78a 26.54a se (±) ns 0.021 0.002 0.001 2.034 1.067 1.178 1.007 1.117 1.126 interaction effect of soil and fertilizer s1t0 6.9 6.9 c 0.060e 0.070b 19.58 17.04 9.50c 11.67 11.56e 12.69e s1t1 6.7 7.4 b 0.077b 0.070b 29.55 20.43 20.00ab 16.67 22.92d 19.79cde s1t2 6.8 7.1 c 0.097a 0.077a 28.52 26.37 16.67bc 20.83 14.58e 19.48cde s1t3 6.8 7.3 b 0.077b 0.077a 29.53 26.70 25.00a 20.33 30.21bc 23.19bc s2t0 7.5 7.4 b 0.070c 0.060c 10.25 10.70 10.00c 9.50 15.29e 15.06dc s2t1 7.2 7.6 a 0.067d 0.077a 19.78 13.05 12.50bc 11.17 28.65cd 22.08cd s2t2 7.4 7.6 a 0.077b 0.077a 25.85 20.74 12.50bc 11.83 36.15ab 30.63a s2t3 7.2 7.7 a 0.077b 0.070b 18.21 15.60 13.50bc 16.67 37.35a 29.90ab se (±) ns 0.030 0.002 0.0018 ns ns 1.666 1.424 1.579 1.5923 cv (%) 2.08 0.72 3.56 4.28 21.99 13.81 19.29 16.62 11.12 12.77 in a column figure(s) having similar letter do not differ significantly at 5% level of significance as per dmrt. the level of available p, k and s in post-harvest soil increased due to the application of fertilizer and manure. the higher levels of post-harvest soil available p were recorded at 0-10 cm (27.19 ppm) and 10-20 cm (23.56 ppm) depths with t2 (50% npks + 5 t cowdung ha−1) treatment. the level p increased more only in the depth of 0-10 cm by using 100% chemical fertilizer but lower concentration was noticed in the depth of 10-20 cm due to more p fixation of chemical fertilizer in the upper layer soil. higher amounts of p moved to 10-20 cm depth where fertilizer and manure were applied may be due to reducing the fixing capacity of soil by application of 132 khan et al. manure. avoola and makinde (2009) found that application of chemical fertilizer with organic manure increase n and p content in post-harvest soil. the post-harvest soil of t3 (50% npks + 2.1 t poultry manure ha−1) treatment gave the higher levels of k and s concentration in the soils of 0-10 cm and 10-20 cm depths. higher concentrations of n, p, k and s were found in different depths of post-harvest soils where fertilizer plus manure were applied due to positive effects of applied manure in combination with fertilizer (table 3). the ph at 10-20 cm depth of post-harvest soil was significantly influenced by interaction effect of different soils and fertilizer and the ph values were more increased in the depths of 10-20 cm in comparison to 0-10 cm depth. the higher levels of ph of post-harvest soils were recorded in the fertilizer applied treatments of both the soils. the ph of sau soil was more increased with the application of different fertilizer, manure may be due to increasing leaching losses of basic cations from the soil. the higher ph (7.7) of post-harvest soil was recorded with the treatment combination s2t3 (sonargaon soil + 50% npks + 2.1 t ha-1 poultry manure) treatment. almost similar n concentrations were found at a depth of 0-10 and 10-20 cm, the higher (0.097%) total n concentration was found in s1t2 (sau soil + 50% npks + 5 t ha−1 cowdung) treatment combination and lowest (0.060 %) was obtained from s1t0 (sau soil + control treatment) treatment combination. higher levels of p were found in the depths of 0-10 cm than 10-20 cm where chemical fertilizer was applied in sau soil (s1t1). the level of p more increased in the depths of 0-10 cm and 10-20 cm of sau soil where inorganic fertilizer and manure were applied. the organic matter influenced the level of p increasing at 10-20 cm depth. the combined effect of fertilizer and soils significantly influenced the k and s content in post-harvest soil and higher levels of k were found in the sau soil compared to sonargaon soil where fertilizer and manure were applied. the highest available potassium concentration was obtained at 0-10 cm of s1t3 (sau soil + 2.1 t ha-1 poultry manure) treatment combinations and lowest (9.50 ppm) from s1t0 (sau soil + no fertilizer). higher levels of s were found in the sonargaon soil compared to sau soil where fertilizer and manure were applied. in the soil of 0-10 cm, the highest available sulfur concentration (37.35 ppm) was obtained from s2t3 (sonargaon soil + 2.1 t poultry manure ha-1) treatment combinations and lowest (11.56 ppm) from s1t0 (sau soil + no fertilizer) treatment combination. similarly in the depth of (10-20) cm, the higher (30.63 ppm) available s in post-harvest soils were obtained from s2t2 (sonargaon soil + 50% npks+5 t cowdung ha−1) and the lower (12.69 ppm) available s concentration was found from s1t0 (sau soil + no fertilizer) treatment combination. conclusionconclusionconclusionconclusion higher n and k leaching were obtained in the undisturbed column where chemical fertilizers were used for boro cultivation. applications of organic plus inorganic fertilizer are recommended for reducing leaching, increasing soil fertility, nutrient accumulation and yield of boro rice. higher n p and k leaching were observed during 30 to 45 days after transplantation of boro rice. the application of organic matter increased more the level of p and s at 0-10 cm and 10-20 cm depths for increasing mobility. the almost similar levels of n and k were found in the initial and post-harvest soil due to higher leaching. acknowledgementacknowledgementacknowledgementacknowledgement the authors gratefully acknowledge the financial support of ministry of science and technology (bangladesh) to conduct this research. 133 effect of fertilizer and manure on the movement of npks in rice referencesreferencesreferencesreferences anderson, b. h. and f. r. magdoff, 2005. relative movement and soil fixation of soluble organic and inorganic phosphorus. j. environ. qual. 34(6): 2228-33. bbs (bangladesh bureau of statistics). 2008. statistical yearbook of bangladesh. statistics division, ministry of planning, govt. of peoples republic of bangladesh. dhaka. bangladesh. p. 71. bouyoucos, g. j. 1926. hydrometer method improved for making particle size analysis of soils. agron. j. 54: 4661-4665. fagaria, n. k., g. d. carvalho, a. b. santo, e. p. b. ferreira and a. m. knupp, 2011. chemistry of lowland rice soils and nutrient availability. commun. soil sci. plant anal. 42: 19131933. gomez, k. a. and a. a. gomez, 1984. statistical procedures for agricultural research. jhon wiley and sons, new york. guntinas, m. e., m. c. leiros, c. trasar, f. trasar-cepeda and g. sotres, 2012. effects of moisture and temperature on net soil nitrogen mineralization. euro. j. soil biol.48: 73-80. hoque, s. a. 1999. nutrient requirements of wet land rice production. proc. int. symp. on paddy soils, september 15-19, beijing, china academia sinica. 281-282. jackson, m. l. 1962. soil chemical analysis. constable and co. ltd london. jalali, m. and d. rowell, 2009. displacement studies on leaching of potassium. environ. geo. 57(1): 4148-4155. miah, m. a. m., m. ishaque and p. k. saha, 2006. integrated nutrient management for improving soil health and rice production. proc. of twenty first brri-dae joint workshops on bridging the rice yield gap for food security. brri, gazipur, bangladesh, 19-21 sept., paper. 11: 115. olsen, s. r., c. v. cole, f. s. watanabe and l. a. dean, 1954. estimation of available phosphorus in soils by extraction with sodium bicarbonate, u.s. dept. agric. circ. p. 929. page, a. l., r. h. miller and d. r. keeney, (ed). 1982. methods of soil analysis part 2, chemical and microbiological properties, second edition american soc. of agron., inc., soil sci. soc. of american inc. madson, wisconsin, usa. pp. 403-430. rahman, m. s., m. r. islam, m. m. rahman and m. i. hossain, 2009. effect of cowdung, poultry manure and urea-n on the yield and nutrient uptake of brri dhan 29. bangladesh res. pub. j. 2: 552-558. reddy, b. g. m., p. s. pattar and p. h. kuchanur, 2005. response of rice to poultry manure and graded levels of npk under irrigated conditions. oryza. 42(2): 109-111. walkley, a. and d. r. black, 1935. an examination of the digestion method for determining soil organic matter and proposed modification of the chronic acid titration method. soil sci. 37: 29-38. xu, m. g., d. c. li, j. m. li, d. z. qin, yagikazuyuki and y. hosen, 2008. effects of organic manure application with chemical fertilizers or nutrient absorption and yield of rice in hunan of southern china. agri. sci. china. 7 (10): 1245-1252. yang, c. m., l. yang, y. yang and z. ouyang, 2004. rice root growth and nutrient uptake as influenced by organic manure in continuously and alternately flooded paddy soils. agric. water. manag. 70 (1): 67-81. bangladesh agron. j. 2019, 22(2): 41-54 morpho-physiological traits of soybean as affected by drought i.a. rima1, m.a. mannan1*, m.a.a. mamun1 and z.u. kamal2 1department of agronomy, 2department of soil science bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding e-mail: mannanbsmrau@yahoo.com (received: 17 december 2019, accepted: 27 february 2020) keywords:morpho-physiology, water stress, soybean abstract an experiment was conducted to study the effects of water deficit stress on morphophysiological parameters in soybean plant in pots at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh during february to june, 2018. seven soybean genotypes namely,i) g00081 ii) g00056 iii) shohag iv) g00078 v) g00137 vi) g00035 and vii) g00060 were grown in two watering regimes viz. control (80% of the field capacity) and water deficit stress (50% of the field capacity). morpho-physiological traits including plant height, number of leaf, relative water content, water saturation deficit, chlorophyll, proline, dry matter and yield were investigated. results indicated that genotypic variability was found in water deficit stress tolerance in soybean. it was found that leaf of the genotype g00081 maintained higher water content, higher accumulation of prolineas well as less reduction of chlorophyll compared to other genotypes studied. total dry matter accumulation and grain yield plant-1was also higher in this genotype. genotype g00081 also showed relatively higher water deficit stress tolerance. on the contrary, g00035 was found to be susceptible showing lower yield. higher water deficit stress tolerance in g00081 was attributed to higher relative leaf water and chlorophylls with accumulation of higher amount of proline. introduction plant experiences water deficit stress either when the water supply to roots becomes difficult or the transpiration rate becomes very high.water deficit stress inhibits the photosynthesis of plants, causes changes in chlorophyll contents and damages the photosynthetic apparatus (escuredoet al., 1998) which ultimately reduces growth promoters (prabaet al., 2009). under water deficit stress, cell expansion of leaf is reduced due to low turgor which is controlled by the processes related to cellular water uptake and cell wall extension that results in decreased leaf area and weight (cramer et al., 1993). the yield and biochemical composition of a plant mainly depends on growth conditions, which is markedly affected by water availability (pacliket al., 1996). soybean is inherently more stress tolerant (singh et al., 2003) than other legume crops but it still suffers considerable damage due to water deficit stress in different regions where rainfall is scanty or irregular and irrigation facility is unavailable. water stress as a key abiotic limiting factor for soybean production can cause soybean yield reduction up to 40% or even more (pathanet al., 2007). mechanisms of water deficit stress tolerance, especially at low water stress involve processes at the cellular level, the most important being osmotic adjustment and protection of the membrane system. osmotic adjustment is the decrease of osmotic potential by the active accumulation of organic as well as inorganic solutes within the cells. high concentrations of inorganic ions become detrimental to cellular metabolism and must be sequestered in the vacuole. in order to keep osmotic balance, specific types of organic molecules (such 42 rima et al. as soluble sugars, betains, proline etc.) are accumulated in the cytoplasm. those compounds protecting plants against stresses by cellular adjustment through the protection of membranes integrity and enzymes stability (farooq et al., 2009) are termed as compatible solutes asthey can be accumulated in high concentrations without impairing normal physiological function. the present study was undertaken to analyze the changes of morpho-physiological parameters that are associated with water deficit stress tolerance of soybean. materials and methods the experiment was conducted in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur during february to june, 2018. it was located at 24.090 n latitude and 90.260 e longitudes at an elevation of 8.4 m from the mean sea level. the soil of the pot was fertilized uniformly with 0.9, 0.8 and 0.8 g urea, triple super phosphate and muriate of potash corresponding to 160-150-150 kg urea, triple super phosphate and muriate of potash per hectare, respectively. ten healthy seeds of seven soybean genotypes namely i) g00081 ii) g00056 iii) shohag iv) g00078 v) g00137 vi) g00035 and vii) g00060 were grown in each pot in 15 february, 2018. light irrigation was given by using the water can to ensure uniform germination of seeds after sowing. two water regimes i) control (80% field capacity) ii) water deficit stress (50% field capacity) were maintained from 1st trifoliate (14 days after germination) stage to maturity using portable digital moisture meter (pogo soil sensor ii, stevens, usa). different intercultural operations were done as and when were necessary. data on plant height, number of leaf / plant, dry weight of leaf, stem and total dry matter were collected at 40 days after drought imposition. leaf chlorophyll, proline and water relations traits were measured at flowering stage. yield and yield contributing data were collected after harvest. the recorded data were statistically analyzed by “mstat-c” software to examine the significant variation of the results due to different treatments. the treatment means were compared by least significance difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion at 40 days after drought imposition, the plant height at control was the highest in shohag (156 cm), while the lowest was in gooo60 (55 cm). under water stress condition the highest plant height was recorded with g00078 (110.33 cm) and the lowest was in g00060 (46.33 cm). relative (per cent of control) plant height of the genotypes ranged from 64% to 94%. highest relative plant height was obtained from genotype g00056 (94%) which was then followed by g00060 (84%), g00137 (81%), g00078 (78%), g00035 (77%), and g00081 (72%); and it was lowest in shohag (64%) (figure 1).plant height reduction due to water stress was lower in gooo56 (16%), while that was higher in shohag (36%). the lower height intheplants under water deficiency occurred, probably duetheaba action,in whichitisproduced inthecellsunder water stress condition and this way inhibited the cell divisionand / or dna synthesis which was supported by wang et al. (1998. similarresults ontheheightreduction in plantsunder waterstressweredescribed bymartinez etal. (2004)studyingatriplexhalimus,aswellaslacerdaetal. (2001)workingwithgenotypes ofsorghumbicolorunder water stress in saline soil. morpho-physiological traits of soybean 43 fig. 1. effect of drought on plant height of soybean at 40 days after drought imposition. bar indicate lsd (0.05). number of leaf of different soybean genotypes varied significantly due to water deficit stress imposition (figure 2). at 40 days after drought imposition, the number of leaves both in control and water stress treatments was recorded to be the highest in g000137 and shohag, respectively. relative number of leaves of the genotypes ranged from 53 to 81% at water stress condition. highest relative number of leaf was obtained from g00081 (81%), followed by g00056 (71%), g00060 (67%), g00035 (65%) and shohag (58%) and it was lowest in g00078 (53%). the reduction in the number of leaves due to water stress was lowest ing00081 (19%), while highest in g00078 (67%). the smallernumberofleavesshownintheplants under waterstresswasdue to the dropin leaf relative water content (lrwc). similar result was also reported by uddin et al. (2013) in mungbean (vignaradiatal.) plant. fig. 2. effect of drought on number of leaf of soybean at 40 days after drought imposition. bar indicate lsd (0.05). 72 94 64 78 81 77 84 0 20 40 60 80 100 120 140 160 180 g00081 g00056 shohag g00078 g00137 g00035 g00060 pl an t h ei gh t ( cm ) genotypes control drought relative values (%) 81 71 58 53 65 66 67 0 20 40 60 80 100 120 g00081 g00056 shohag g00078 g00137 g00035 g00060 n um be r o f l ea f p la nt =1 genotypes control drought relative values (%) 44 rima et al. they found significant effect of water stress on the number of leaves per plant at 30, 75 and 90 das (days after sowing). the result showed that as the water stress increased, the number of leaves per plant decreased indicating that water stress had a direct effect on senescence and dropped out the leaves. effect of water deficit stress on leaf dry matter production was statistically significant (figure 3). the highest leaf dry matter under control was recorded in g00137 (19.40 g), followed by g00078 (17.30 g), shohag (16.09 g), g00081 (11.70 g), g00056 (10.85 g) and g00035 (8.18 g) while the lowest was found in g00060 (2.40 g). on the other hand, under water deficit stress condition shohag produced the highest leaf dry matter (10.34 g), followed by g00137 (8.30 g), g00056(5.88 g), g00078 (5.31 g), g00035 (4.01 g) and g00081 (3.66 g);and the lowest was recorded from g00060 (2.59 g). relative leaf dry matter of the genotypes ranged from 43% to 73%. highest relative leaf dry matter was obtained from g00081 (73%) and it was lowest in g00137 (43%). the reduction of the leaf dry matter due to water stress was lower in g00081 (27%), while that was higher in g00137 (57%). khan (2014) reported that leaf traits like leaf number, leaf area and its dry weight of the soybean genotypes were sharply decreased when the plants were exposed to water and salt stress conditions.fentaet al. (2014) also found significant differences in leaf dry matter, stem dry matter and shoot dry matter in wellwatered and drought conditions. leaf dry weight was reduced in water stressed cotton plants as was reported by pace et al. (1999). fig. 3. effect of drought on leaf dry weight of soybean at 40 days after drought imposition. bar indicate lsd (0.05). petiole dry weight of soybean genotypes was affected significantly due to water stress (figure 4). the highest petiole dry weight under control was recorded in g00137 (10.40 g), followed by shohag (7.54 g), g00078 (5.23 g), g00056 (5.15 g), g00081 (4.51 g) and g00035 (2.33 g);whereas the lowest in g00060 (1.18 g). on the other hand, under water deficit stress condition g00137 produced the highest petiole dry matter (3.46 g) while the lowest was recorded from g00060 (0.76 g). relative petiole dry matter of the genotypes ranged from 33% to 53%. highest relative leaf dry matter was obtained from g00060 (53%) and it was lowest in g00137 (33%). the reduction of the leaf dry matter due to water stress was lower in g00061 (47%), while that was higher in g00137 (67%). 73 54 61 51 43 49 64 0 10 20 30 40 50 60 70 80 g00081 g00056 shohag g00078 g00137 g00035 g00060 le af d ry w ei gh t ( g pl an t-1 ) genotypes control drought relative values (%) morpho-physiological traits of soybean 45 fig. 4. effect of drought on petiole dry weight of soybean at 40 days after drought imposition. bars indicate lsd 0.05). the effect of water deficit stress on stem dry matter production was statistically significant (figure5). the highest stem dry matter under control condition was recorded in g00137 (18.17 g) which was followed by g00078 (17.49 g), shohag (15.18 g), g00056 (10.18 g), g00035 (6.04 g) and g00081 (3.93 g); and the lowest was found in g00060 (2.03 g). on the other hand, under water stress condition g00078 produced the highest stem dry matter (9.06 g) while the lowest was recorded from g00060 (1.36 g). relative stem dry matter of the genotypes ranged from 28% to 65% at water deficit conditions showing the highest with g00081 (65.03%) which was then followed by g00060 (63%), g00078 (52%), g00035 (50%), shohag (44%) and g00137 (42%) while it was lowest in bari soybean-5 (36.72%). fig. 5. effect of drought on stem dry weight of soybean at 40 days after drought imposition. bars indicate lsd (0.05). 51 39 51 47 33 48 53 0 10 20 30 40 50 60 70 80 g00081 g00056 shohag g00078 g00137 g00035 g00060 pe tio lr dr y we ig ht (g p la nt -1 ) genotypes control drought relative values (%) 65 28 44 52 42 50 63 0 10 20 30 40 50 60 70 g00081 g00056 shohag g00078 g00137 g00035 g00060 st em d ry w ei gh t ( g pl an t-1 ) genotypes control drought relative values (%) 46 rima et al. the reduction of the stem dry matter due to water stress was lower in binasoybean-1 (52.97%), while that was higher in bari soybean-5 (63.28%). canavaret al. (2014) reported thatmorphological components such as leaf stem and total dry weight of sunflower cultivars were found to be mostly influenced by water stress. the lowest reduction in terms of leaf, stem and total dry weight was obtained from the cultivar that grown under well-watered condition as compared with the other sunflower cultivars under the water stress. moussa (2011) reported that water deficits decreased the dry weight of stems and leaves; total biomass and seed yield of soybean genotypes, but did not affect the dry weight of roots. pod dry weight of soybean genotypes was affected significantly due to water stress (figure 6). the highest pod dry weight under control was recorded in g00035 (15.30 g), followed by g00056 (12.08 g), g00060 (11.79 g), g00081 (10.94 g), g00137 (10.67 g) and shohag(9.42 g) the lowest was found in g00078 (7.66 g). on the other hand, under water deficit stress condition g00035 produced the highest pod dry matter (9.55 g) and the lowest was recorded from g00137 (4.78 g). relative pod dry matter of the genotypes ranged from 41% to 77% which was the highest in g00081 (77%) and lowest in g00056 (41%). the reduction of the pod dry matter due to water stress was lower in g00081 (33%), while that was higher in g00056 (69%). fig. 6. effect of drought on pod dry weight of soybean at 40 days after drought imposition. bar indicate lsd (0.05). the effect of water deficit stress on total dry matter production was statistically significant (table figure 7). the highest total dry matter under control was recorded in g00137 (58.64 g), followed by shohag (49.34 g), g00078 (47.7 g), g00056 (38.26 g), g00035 (32.19 g) and g00081 (22.09 g) and the lowest was found in g00060 (17.42 g). shohag produced the highest total dry matter (25.99 g) and the lowest was recorded from g00060 (12.52 g). relative total dry matter of the genotypes ranged from 41% to 71% at water deficit conditions. highest relative total dry matter was obtained from g00081 (72%) and lowest in g00056 (41%). the reduction of the total dry matter due to water stress was lower in g00081 (28%), while that was higher in g00056 (59%). water stresscausedsignificantdecreasein plant growth. these results are in harmony with abassandmohamed(2011)who reportedthatthe plant growthparametersof commonbean(shootand root length, fresh and dry weights of shoots and roots)decreasedsignificantly withincreasingdrought stressascomparedwithcontrolplants.suchdecline inshootand rootgrowthin response todroughtmight be due to either decrease in cell elongation, cell turgor, cell volume and eventually cell growth (banonetal., 77 41 55 62 45 62 76 0 10 20 30 40 50 60 70 80 90 g00081 g00056 shohag g00078 g00137 g00035 g00060 po d dr y we ig ht (g p la nt -1 ) genotypes control drought relative values (%) morpho-physiological traits of soybean 47 2006),and/orduetoblockingupof xylemandphloemvesselshinderingphotosynthetictranslocation(lavisoloand schuber,1998). water stress inhibits dry matter production largely through its inhibitory effects on leaf expansion, leaf development and consequently reduced light interception (nam et al., 1998). fig. 7. effect of drought on total dry weight of soybean at 40 days after drought imposition. bar indicate lsd (0.05). relative water content in leaf indicates the water status in leaf. it was found that under water stress condition leaf moisture decreased significantly (figure 8). highest relative water content was found under control in the leaves of g00035 (89.4%) followed by g00081 (86.38%), shohag (85.86%), g00056 (83.12%), g00060 (81.09%) and g00078 (63.9%); and it was lowest in g000137 (61.02%). but under drought condition the highest relative water content was observed in genotype g00056 (75.18%) and the lowest was in g00078 (38.09%). fig. 8. effect of drought on relative water content of soybean at flowering stage. bar indicate lsd (0.05). water saturation deficit increased in drought condition in all the genotypes (figure 9). highest water deficit was found in g00078 (38.04%) and it was lowest in g00081 (14.17%). 72 41 53 45 41 55 71 0 10 20 30 40 50 60 70 80 90 100 g00081 g00056 shohag g00078 g00137 g00035 g00060 to ta l d ry w ei gh t ( g pl an t-1 ) genotypes control drought relative values (%) 0 20 40 60 80 100 120 g00081 g00056 shohag g00078 g00137 g00035 g00060 re lat ive w at er co nt en t ( % ) genotypes control drought 48 rima et al. veluandpalanisami(2002) reportedthat waterstresssignificantly reducedrelativewatercontentoftheplant. nayyarand gupta (2006) reported that the decrease in the rwc in response to drought stress has been noted in a wide variety of plants saying that when leaves were subject to water stress, leaves exhibited large reductions in rwc and water potential. siddique et al. (2001) found that exposure of plants to water stress substantially decreased the leaf water potential, relative water content and transpiration rate with a concomitant increase in leaf temperature. the effect of water deficit stress on total chlorophyll of soybean genotypes was significant at 40 days after water stress imposition (figure 9). the total chlorophyll in well watered condition was highest in g00060 (4.32 mgg-1 fresh weight of leaf) and it was lowest in shohag (3.45 mgg-1fresh weight of leaf). drought stress decreased chlorophyll content in leaf of all the genotypes and it was highest in g00060 (3.43 mgg-1fresh weight of leaf). it was reportedthatthis pigmentwassensitive toincreasingenvironmental stress(terziet al., 2010).thedecreaseintotalchlorophyllcontent mayhaveresultedfromadecreaseinleafwaterstatus inthesoybean. fig. 9. effect of drought on total chlorophyll of soybean leaf at flowering stage. bar indicate lsd (0.05). at 40 days after water deficit stress imposition, the highest amount of proline was recorded in g00081 (1.75 µ mole g-1 fw leaf), followed by g00137 (1.73 µ mole g-1 fw leaf), g00060 (1.69 µ mole g-1 fw leaf), g00078 (1.64µ mole g-1 fw leaf) and shohag (1.60 µ mole g-1 fw leaf) while the lowest was recorded in g00035 (1.38 µ mole g-1 fw leaf). (figure 10).karimi and mohseni (2013) found that drought stress significantly enhanced accumulation of proline in the leaf of all the cultivars viz., shirale, oscar, con-ii, rainbow and 19h at flower initiation stage, and there were variability of proline accumulation among the genotypes. hossain et al. (2014) found that progressive water restriction increased the concentration of proline in leaves of soybean genotypes. nareshet al. (2013) reported similar increasing trend of proline content in genotypes under water deficit of vigna radiate l. 0 1 2 3 4 5 6 7 8 g00081 g00056 shohag g00078 g00137 g00035 g00060 to ta l c hl or op hy ll ( m m ol g -1 fre sh le af ) genotypes control drought morpho-physiological traits of soybean 49 fig. 10. effect of water deficit stress on proline content at flowering stage.bar indicate lsd (0.05). the effect of water deficit stress on number of podsplant-1was statistically significant (table 1). the highest number of podsplant-1under control was recorded in g00035 (104) and the lowest in g00081 (53). on the other hand, under water stress condition the genotype g00081 had the highest number of pods (47.67) while the lowest was recorded from g00137 (39). relative number of podsplant-1of the genotypes ranged from 43% to 90% at water deficit condition. highest relative number of podsplant1was obtained from g00081 (90%), followed by g00060 (78%), g00078 (53%) and g00137 (45%);and it was lowest in g00056 (43%). the reduction of the number of podsplant-1due to water stress was lower in g00081 (10%), while that was higher in g00056 (57%). thesignificantreductioninnumberofthe harvested pods plant-1underwaterstressmaybeattributed tothe abscissionofthereproductivestructures.gwathmey andhall(1992)reportedsimilar results. water stress caused by water shortage decreased pod number in pea as was reported by duzdemiret al. (2009). the effect of water deficit stress on number of seeds pod-1 was statistically significant (table 1). the highest number of seedspod-1under control was recorded from g00081 (2.26) and the lowest was found in g00137 (1.42). on the other hand, under water stress condition,g00060 produced the highest number of seedspod-1(1.73) while the lowest was recorded from g00137 (0.93). relative number of seedspod-1of the genotypes ranged from 61 to 92% at water deficit conditions. highest relative number of seedspod-1was obtained from g00060 (92%) which was then followed by g00056 (78%), g00081 (75%), and it was lowest in g00035 (59%). the reduction of the number of seedspod-1due to water stress was lower in g00060 (8%), while that was higher in g00035 (41%). kazietal.(2002)showed thatnumber ofseedshead-1reduced duetoa long droughtperiodinsunflower. thereductionin numberof seed pod-1andseedsizeunder water stress treatmentsmay beattributed to the limitationof dry matterpartitioning tothereproductivesinkorevenseed formation factorsaswasreported byturkand hall (1980). bord and hartville (1998) citedthat under drought stress condition, seed number reduced in all plants, mainly because of the abscission of flowers and pods. 0.00 0.50 1.00 1.50 2.00 2.50 g00081 g00056 shohag g00078 g00137 g00035 g00060 pr ol in e ( µ m ol es g -1 fre sh w ei gh t o f l ea f) genotypes control water deficit stress 50 rima et al. table 1. number of podsplant-1 and number of seeds pod-1 of seven selected soybean genotypes as affected by drought genotypes number of pods plant-1 number of seeds pod-1 control drought control drought g00081 53.00 47.67 (90) 2.26 1.70 (75) g00056 101.67 43.67 (43) 2.01 1.57 (78) shohag 100.00 44.33 (44) 2.04 1.21 (59) g 00078 75.67 40.33 (53) 1.97 1.19 g00137 87.00 39.00 (45) 1.42 0.93 (65) g00035 104.00 45 (43) 1.84 1.08 (59) g00060 57.00 44.33 (78) 1.88 1.73 (92) lsd(0.01) 1.30 0.18 cv (%) 8.21 5.76 values presented in parentheses indicate percent of the control. the effect of water deficit stress on the weight of 100 seed was statistically significant (table 2). the highest seed weight both under control and water stress conditions was recorded in g00081 (14 g and 12.48 g) and the lowest in g00037 (10.33 g and 7.0 g). relative weight of 100 seed of the genotypes ranged from 65% to 89% at water deficit conditions. table 2. 100-seed weight and grain yield plant-1of seven selected soybean genotypes as affected by drought genotypes 100-seed weight(g) grain yield plant-1 (g) control drought control drought g00081 14.00 12.48 (89) 8.63 6.38 (74) g00056 13.99 11.37 (81) 7.95 4.26 (54) shohag 12.42 9.32 (75) 11.64 5.33 (46) g 00078 11.32 8.80 (78) 10.76 5.23 (49) g00137 10.33 7.00 (68) 10.54 4.48 (43) g00035 13.48 8.82 (65) 12.67 4.91 (39) g00060 12.13 10.66 (88) 8.24 5.82 (71) lsd(0.01) 3.19 0.22 cv (%) 7.01 6.76 values presented in parentheses indicate percent values to the control. highest relative weight of 100-seed was obtained from g00081 (89%) followed by g00060 (88%), g00056 (81%), g00078 (78%), shohag (75%) and g00137 (68%); and it was lowest in g00035 (65%). morpho-physiological traits of soybean 51 the reduction of the weight due to water stress was lower in g00081 (11%) while that was higher in g00035 (35%). soybean yield is more sensitive to drought stress during the early reproductive stage (i.e. flowering to early pod expansion) than other developmental stages (westgate and peterson, 1993). in another experiment it was revealed that the effects of drought stress and cultivar were significant on fertile pod plant-1, seeds plant-1, seed yield, hundred kernels weight, seeds pod-1 of soybean (malekiet al., 2013). the effect of water deficit stress on yield was statistically significant (table 2). the highest yield under control condition was recorded in g00035 (12.67 g) while the lowest in g00056 (7.95 g). on the other hand, under water stress conditions, g00081 produced the highest yield (6.38 g) and the lowest was recorded from g00056 (4.26 g). relative yield of the genotypes ranged from 39% to 74% across water deficit conditions. highest relative yield was obtained from g00081 (74%) followed by g00060 (71%), g00056 (54%), g00078 (49%), shohag (46%) and g00137 (43%) and it was lowest in g00035 (39%). the reduction of the yield plant-1 due to water stress was lower in g00081 (26%), while that was higher in genotype g00035 (61%) indicating that this genotype is susceptible. drought induced yield reduction was alsoreportedinmany cropspecies,the extent of whichdepended upontheseverityanddurationof thestressperiod.in maize, water stress reducedyield by delayingsilking,thusincreasingtheanthesis-tosilkinginterval.thistraitwashighlycorrelatedwithgrainyield,specificallyearandkernelnumberplant1(cattivellietal., 2008). followingheading,droughthadlittleeffectontherateof kernelfillinginwheat,butitsduration(timefromfertilizationtomaturity)wasshortenedanddryweightreduced at maturity(wardlawandwillenbrink,2000).droughtstressin soybean reduced totalseedyield(fredericketal.,2001).in the present study,thereductioninseedyieldunderwaterstress wasassociatedwithdramaticdecreaseinalltheseyield components. supporting evidenceswere reported byludlow and mushow(1990). theyattributed the reduction inseedyieldunderwaterstresstothe reduction innumberofpodsplant-1,numberofseedspod-1 and seed weight. asletal.(2003)citedthatincreaseintheirrigationintervalresultedin thereduction intheseedyielddue to theincreasein thepercentage ofinfertileseeds. conclusion from the above results, it may be concluded that wide range of variability of morpho-physiological parameters associated with water deficit stress tolerance was found in the soybean genotypes tested. water deficit stress exerted inhibitory effects on dry matter accumulation and yield of soybean. g00081 showed a relatively higher water deficit stress tolerance while g00035 was susceptible in terms of dry matter accumulation and yield performance. it may be concluded that higher water deficit stress tolerance in g00081 was associated with higher water content in leaf, higher accumulation of proline and less reduction of leaf chlorophyll. acknowledgement we are grateful to the ministry of education, government of bangladesh for funding the research. references abass, s.m. and h.i. mohamed. 2011. alleviation of adverse effects of drought stress on common bean (phaseolus vulgaris l.) by exogenous application of hydrogen peroxide. bangladesh j. bot. 41: 7583. 52 rima et al. asl, k.k., d.mazaheriands.a. peighambari. 2003.effect of four irrigation intervalson theseedyieldandquantitativecharacteristics of sunflowercultivars.iranianj.agric. sci. 34(2):293-301. banon, s., j. ochoa, j.a. franco, j.j. alarcon and m.j. sanchez-blanco. 2006. hardening of oleander seedlings by deficit irrigation and low air humidity. environ. exp. bot. 56: 36-43. bord, j.e. and b.g. harville. 1998. late-planted soybean yield response to reproductive source/sink stress. crop sci. 38: 763-771. canavar, o., k.p. gotz, f. ellmer, f.m. chmielewskiand m.a. kaynak. 2014. determination of the relationship between water use efficiency, carbon isotope discrimination and proline in sunflower genotypes under drought stress. aust. j. crop sci. 8(2): 232-242. cattivelli, l., f. rizza, f.w. badeck, e. mazzucotelli, a.m. mastrangelo, e. francia, c. mare, a. tondelli and a.m. stanca. 2008. drought tolerance improvement in crop plants: an integrative view from breeding to genomics, field crops res. 105: 1-14. cramer, g.r. and d.c. bowman. 1993. cell elongation control under stress conditions. in: handbook of plant and crop stress, m. pessarakli (ed.). marcel dekker, new york, pp.303-319. duzdemir, o., a. kurunc and a. unlukara. 2009. response of pea (pisumsativum) to salinity and irrigation water regime. bulgarian j. agril. sci. 15(5): 400-409. escuredo, i.p., c. arrese-igor and m. becana. 1998. oxidative damage in pea plants exposed to water deficit or paraquat. plant physiol. 116: 173-181. farooq, m., a. wahid, n. kobayashi, d. fujita and s.m.a. basra. 2009. plant drought stress: effects, mechanisms and management. agron. sustain. dev. 29: 185-212. fenta, b.a., s.e. beebe, k.j. kunert, j.d. burridge, k.m. barlow, j.p. lynch and c.h. foyer. 2014. field phenotyping of soybean roots for drought stress tolerance. agron.j.4: 418-435. frederick, j.r., c.r. camp and p.j. bauer. 2001. drought-stress effects on branch and main stem seed yield and yield components of determinate soybean. crop sci. 41:759-763. gomez, a.a. and a.a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. pp.20-2015. gwathmey,c.o.and a.e. hall. 1992. adaptation to mid-season droughtofcowpea genotypeswith contrasting senescence traits. crop sci. 32: 773-778. hossain, m.m., x. liu, x. qi, h.m. lam and j. zhang. 2014. differences between soybean genotypes in physiological response to sequential soil drying and rewetting. the crop j. 2: 366-380. karimi, m. and a.b. mohseni. 2013. effects of osmotic stress on soybean varieties. j. nov. appl. sci. 2(4): 101-105. kazi, b.r., f.c. oad, g.h. jamro, l.a. jamali and n.l. oad. 2002. effect of water stress on the growth, yield and oil content of sunflower. pak. j. appl. sci. 2: 550-552. khan, m.s.a. 2013. evaluation of soybean genotypes in relation to yield performance, salinity and drought tolerance. a ph. d dissertation. department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur-1706, bangladesh. lacerda, c.f., j. cambraia, m.a. oliva and h.a. ruiz. 2001. plant growth and solute accumulation and distribution in two sorghum genotypes, under nacl stress. rev. bras. fisiol. veg. 13: 270-284. lavisolo, c. and a. schuber. 1998. effects of water stress on vessel size xylem hydraulic conductivity in vitisviniferal. j. exp. bot. 49: 693-700. ludlow, m.m. and r.c. muchow. 1990. a critical evaluation of traits for improving crop yields in water limited environments.adv.agron. 43: 107-153. maleki, a., a. naderi, r. naseri, a. fathi, s. bahamin and r. maleki. 2013. physiological performance of soybean cultivars under drought stress. bull. env. pharmacol. life sci. 2(6): 38-44. martinez, j.p., s. lutts, a. schanck, m. bajji and j.m. kinet. 2004. is osmotic adjustment required for water stress resistance in the mediterranean shrub atriplexhalimus l. plant physiol. 161(9): 1041-1051. morpho-physiological traits of soybean 53 moussa, h.r. 2011. low dose of gamma irradiation enhanced drought tolerance in soybean. bulg. j. agric. sci. 17: 63-72. nam, n.h., g.v. subbaroa, y.s. chauhan and c. johansen. 1998. importance of canopy attributes in determining dry matter accumulation of pigeon pea under contrasting moisture regimes. crop sci. 38: 955-961. naresh, r.k., purushottam, s.p. singh, a. dwivedi and v. kumar. 2013. effects of water stress on physiological processes and yield attributes of different mungbean (l.) varieties. african j.biochem. res. 7(5): 55-62. nayyar, h. and d. gupta. 2006. differential sensitivity of c3 and c4 plants to water deficit stress: association with oxidative stress and antioxidants. environ. exp. bot. 58: 106-113. pace, p.f., h.t. crale, j.t. cothren and s.a. senseman. 1999. drought induced changes in shoot and root growth of young cotton plants. j. cotton sci. 3: 183-187. paclik, r.l., sakova, and v. curn. 1996. reaction of different cultivars of soybean subsp. oleifera to water stress. fytotechnicka-rada. 1: 55-62. pathan, m.s., j.d. lee, j.g. shannon and h.t. nguyen. 2007. recent advances in breeding for drought and salt stress tolerance in soybean. m.a. jenks, p.m. hasegawa, and s. m. jain (eds). in: advances in molecu-lar breeding toward drought and salt tolerant crops. springer nether-lands. pp.739-773. praba, m.l., j.e. cairns, r.c. babu and h.r. lafitte. 2009. identification of physiological traits underlying cultivar differences in drought tolerance in rice and wheat. j. agron. crop sci. 195: 30-46. siddique, m.r.b., a. hamid and m.s. islam. 2001. drought stress effects on water relations of wheat. bot. bull. acad. sin. 41: 35-39. singh, b.b., p. hartmann, c. fatokun, m. tamo, s. tarawali and r. ortiz. 2003. recent progress on cowpea improvement. chronic hort. 43: 8-12. terzi, r., a. sağlam, n. kutlu, h. nar and a. kadıoğlu. 2010. impact of soil drought stress on photochemical efficiency of photosystem ii and antioxidant enzyme activities of phaseolus vulgaris cultivars. turk j. bot.34: 1-10. turk,k.j.and a.e. hall. 1980. drought adaptation of cowpea. iv:influenceofdroughtonwateruseand relationwithgrowthandseedyield.agron.j.72:440-448. uddin s., s. parvin and m.a. awal. 2013. morpho-physiological aspects of mungbean (vignaradiatal.) in response to water stress. int. j. agric. sci. res. 3(2): 137-148. velu, g. andk.palanisami.2002.impactofmoisturestressongrowthandyieldof sunflower. madras agric. j. 88(10-12): 660-665. wardlaw,i.f. andj. willenbrink.2000. mobilizationoffructanreservesand changesinenzymeactivities inwheatstemscorrelatewithwater stress duringkernelfilling,newphytol.148: 413-422. warpo. 2005. annual report, water resource planning organization. dhaka, bangladesh. westgate, m.e. andc.m.peterson. 1993. flower and poddevelopmentinwater-deficient soybeans (glycinemaxl.merr.). j. exp. bot. 44(1): 109-117. bangladesh agron. j. 2018, 21(2): 25-32 phenology, growth and pod yield of french bean (phaseolus vulgaris l.) as influenced by temperature variations under different sowing dates s.s.kakon*, m.a.k. mian, r.r.saha, s.s.nasreen1, q.naher2 and m.a.hossain2 agronomy division, bangladesh agricultural research institute (bari) 1regional agricultural research station, akborpur, moulvibazar 2on-farm research division, bari, gazipur *corresponding author, e-mail: kakonbari@gmail.com (received: 7 january 2019, accepted: 23 march 2019) keywords: temperature, french bean, phenology, growth and pod yield abstract the experiment was conducted at the research field of the agronomy division, bangladesh agricultural research institute (bari), bangladesh during rabi season of 2017-2018 to evaluate the flowering behavior and pod yield of french bean. three varieties namely bari jharsheem-1, bari jharsheem-2 and bari jharsheem-3 were sown on 30 november, 15 december and 30 december, respectively for getting temperature variation. sowing dates based on temperature variation, significantly affect the flowering behaviour and pod yield of french bean varieties. developmental events were badly affected when sown on 30 december. crop accumulated lower gdd for different development events when sown late. flowering duration of 30 november sowing were longer due to prevailing low temperatures (min.10.3-11.4 °c and max 23.7-24.5 °c) (table 2). on the contrary, minimum flowering duration was recorded in 30 december sown crop (11-17 days). minimum duration might be due to prevailing high temperature (min.14.9-15.3 °c and max 27.6-28.8 °c) that shorten the flowering duration of all french bean varieties. pod yield of all the varieties were more at november sowing and decreased towards late sowing. november 30 sowing performed better in relation to yield components and yield which was very close to 15 december sowing. bari jharsheem-1 produced the highest pod yield (16.77t ha-1) in 30 november sowing. french bean had been sown on november to december showed the greater variability in respect of flowering, flowering duration and the number of pods. the results revealed that november would be the optimum sowing date (15 nov.-30 nov.) for maximum pod yield of french bean var. bari jharsheem-1. introduction french bean (phaseolus vulgaris) is popularly known as rajma, haricot bean, kindey bean, snap bean, navy bean, field bean, dry bean, pole bean etc and it is also known as ‘jhar sheem’ in bangladesh. french-bean is one of the important legume crops worldwide for direct human consumption. due to its wide spread utilization of both the green pods and dried seeds. green pods are rich in vitamins, protein and minerals. besides this, a huge amount of french bean is consumed as soup. its demand especially to the urban people is increasing day by day. the growth and development of any crop is primarily governed by the environmental conditions of the soil and climate. sowing time of any crop depends on environmental conditions; mainly air temperature and rainfall greatly affect the growth and development of bean plants (szyrmer et al., about:blank 26 kakon et al. 1992; gross and kigel, 1994; mouhouche et al., 1998; ibarra perez et al., 1999). the sowing times has marked effects on growth and yield of most crops in different parts of the world as delay in sowing beyond the optimum time usually results in yield reduction (vange and obi, 2006). late sowing is one of the major causes of low yield of french bean. in bangladesh, french bean is usually cultivated after harvesting of t. aman . but sowing time of french bean sometimes delayed due to late harvesting of t. aman, as a result the crop face higher temperature during its reproductive stage. temperature based agro-climatic indices such as growing degree days (gdd) can be quite useful in predicting growth and yield of any crop. growing degree days are based on the concept that, real time to attain a phenological stage is linearly related to temperature range between base temperature (tb) and optimum temperature. according to wilczek and ćwintal (2003), very high air temperatures and low rainfall much shortened the period of red clover flowering, whereas low temperatures along with high and frequent precipitation resulted in the prolongation of the plant’s flowering even to 40-50 days. wallace et al. (1991) also proved a significant shortening of the period to the beginning of plant flowering along with the increase of air temperature in the range of 12-28 °c. the mean temperature requirement for optimum growth of french bean has been reported to be 14 – 24 °c (kay, 1979), 16-30 °c (nonneck, 1989) and 15-25 °c (rashid, 1999). heitholt et al. (1986) also reported that late flowers aborted more frequently than did early flowers in soybean. pod abscission was increased by delay sowing which was accordance with fisher (1980). high temperature stress causes substantial loss in crop yield due to the damage of reproductive organs (savin and nicolas, 1996) and reduced length of reproductive period. so, it is now essential to study the crop growth behaviors in changing climatic condition for future requirement. therefore, the present experiment was conducted to evaluate the growth and development, flowering behaviour and pod yield under different temperature variation from different sowing time. materials and methods the experiment was conducted at the agronomy research field of bangladesh agricultural research institute, bangladesh during rabi season of 2017-18. the experimental site was located at chhiata series under agro-ecological zone-28 (aez-28), latitude 23°59′ n and longitude 90°24′ e. before opening the land, the soil samples were taken from the spots of the experimental area and analyzed from the soil science division, bari. the soil analysis showed that the soil of the experimental field was loam in texture and low in organic matter (1.27%). the soil was acidic in nature with ph 6.1 and contained very low amount of total nitrogen (0.067%), phosphorus (9.6%), sulphur (12%), zinc (2 meq/100 g) and medium amount of potassium (0.18 meq/100 g). the rainfall during the period was 42.0 mm in 2017-18. the 12 treatment combinations were studied. the main plot treatments consisted of three sowing dates viz. 15 november, 30 november, 15 december and 30 december while sub-plot treatments consisted of three varieties (bari jharsheem-1, bari jharsheem-2 and bari jharsheem-3).the experiment was laid out in a splitplot design with 3 replications. the unit plot size was 3.0 m × 3.0 m. the crop was fertilized with 120-40-60 -12-3 n-p-k-s-zn ha-1, respectively (frg, 2012). half of n and full doses of other fertilizers were applied at the time of final land preparation and the rest urea was top dressed at 30 das. seeds were treated with vitavax phenology, growth and pod yield of french bean 27 and sown continuously in 30 cm apart rows. plant to plant distance was maintained by 10 cm. hand weeding was done at 20 and 35 days after sowing (das). pre sowing irrigation was given to the crop for uniform emergence. the crop was attacked by cutworm (agroti sipsilon) and hairy caterpillar (spilarctia obliqua) at early growth stage. the cutworm was controlled by hand picking. perfecthion 40 ec @ 2.0 ml l-1 of water was sprayed at an interval of 7-10 days for 3 times to control hairy caterpillar. the phenological data were recorded by field monitoring every day. at each harvesting time, five plants were taken randomly from each plot to record the data on yield components. growing degree days (gdd) were computed considering base temperature as 8 °c (thavaprakaash et.al, 2007). in present study, a different thermal index like growing degree days (gdd) was calculated to find the relationship of these thermal indices with different phenological stages. the agro-climatic indices were computed as follows: growing degree day (gdd) = {(t max +t min)/2}-tb, here, tb is base temperature pod yield was recorded from an area of 3 m x 2 m avoiding border effect. data on different parameters were subjected to analysis of variance and the treatment means were compared by least significant difference (lsd) test. results and discussion duration and growing degree days for vegetative phase and crop growth duration of french bean crop developmental events and growth duration were influenced by the interaction effects (table 1) of sowing date and variety. crop growth duration was recorded maximum in bari jharsheem -2 when sown on 30 november (69 days) with the highest gdd (977.35) followed by 15 december sowing (65 days) with the 2nd highest gdd (914.25) and the second crop growth duration was recorded maximum in bari jharsheem-1 with the 2nd highest gdd (945.85). the minimum duration (49 days) with minimum gdd (672.65) was recorded in bari jharsheem-3 at 30 december sowing. the reasons for variation in growth duration might be due to increased day and night temperature at later sowing (fig. 1). the late sown crops flowered earlier with reduced vegetative durations than those of early sown ones. the highest duration for flowering was recorded in 30 november (21-24 days) sowing with maximum gdd (857.55-977.35). the lowest duration for flowering was recorded (11-17 days) with maximum gdd (672.65-818.40) in 30 december sowing. similar result was also reported by rangaswamy (1975). table 1. required duration and growing degree days for crop development events and crop duration of french bean varieties by sowing date during rabi (2017-2018) sowing date  variety emergence days to required .1st flowering duration (days) gdd duration (days) gdd d1  v1 6 120.50 35 599.10 d1  v2 7 140.00 37 630.95 d1  v3 7 140.00 31 540.50 d2  v1 7 108.80 41 606.95 d2  v2 8 125.35 43 629.30 d2  v3 8 101.35 39 590.20 d3  v1 8 120.30 40 533.55 26 kakon et al. d3  v2 9 134.70 42 561.80 d3  v3 8 96.30 39 518.65 d4  v1 8 109.30 38 490.90 d4  v2 9 117.85 35 441.25 d4  v3 8 109.30 34 426.35 cont,d sowing date  variety flowering duration (day) crop growth duration (day) duration (days) gdd duration (days) gdd d1  v1 18 262.75 56 885.15 d1  v2 21 281.15 61 937.25 d1  v3 17 255.95 55 874.9 d2  v1 24 302.00 67 945.85 d2  v2 24 312.05 69 977.35 d2  v3 21 252.65 61 857.55 d3  v1 23 347.45 63 882.15 d3  v2 22 280.65 65 914.25 d3  v3 18 259.15 57 782.25 d4  v1 17 287.85 57 818.4 d4  v2 12 198.30 52 723.75 d4  v3 11 177.40 49 672.65 v1 = bari jharsheem-1, v2 = bari jharsheem-2, v3 = bari jharsheem-3, d1 = 15 november, 30 november, d2 = 15 december, d4 = 30 december. fig. 1. mean temperatures (max. and min.) during crop growing period in 2017-18 temperature is an important factor of flowering in french bean (fig. 1). flowering duration in all varieties was also observed maximum in 30 november sowing (21-24 days). flowering duration of 30 november sowing were longer due to prevailing low temperatures (min.10.3-11.4 °c and max 23.7-24.5 °c) (table 2). on the contrary, minimum flowering duration was recorded in 30 december sown crop (11-17 days). minimum duration might be due to prevailing phenology, growth and pod yield of french bean 27 high temperature (min.14.9-15.3 °c and max 27.6-28.8 °c) that shorten the flowering duration of all french bean varieties. similar results were also observed by łabuda and brodaczewska (2007). table 2. prevailing average temperature during the duration of flowering of french bean varieties sown at different dates sowing date flowering duration bari jharsheem-1 bari jharsheem-2 bari jharsheem-3 max. tem. °c min. tem. °c max. tem. °c min. tem. °c max. tem. °c min. tem. °c 15 november 25.90 13.00 25.1 11.5 26.6 13.6 30 november 24.5 10.9 24.8 11.4 23.7 10.3 15 december 26.9 13.4 26.9 13.5 26.4 12.9 30 december 28.8 15.3 27.7 15.3 27.6 14.9 total dry matter the yield of a crop is mainly determined by the accumulation of dm and its partitioning into the economic sink. at flowering stage, the total dry matter production of french bean varieties varied due to different sowing dates (fig. 2). significantly the highest total dry matter (8.93 g plant-1) was obtained in bari jharsheem-2 had been sown on 30 november. the lowest total dry matter (4.02 g plant-1) was recorded in bari jharsheem-2 had been sown at 30 december. fig. 2. total dry matter production of french bean varieties at flowering stage under different sowing date. v1 = bari jharsheem-1, v2 = bari jharsheem-2, v3 = bari jharsheem-3, d1 = 15 november, 30 november, d2 = 15 december, d4 = 30 december. yield and yield components yield and yield attributes of french bean varieties were significantly affected by sowing dates (table 3). bari jharsheem-1 produced the tallest plant (45.93cm) in 30 november sowing. the shortest plant (25.47 cm) was obtained in bari 26 kakon et al. jharsheem-2 when crop sown on 30 december. significantly the highest number of pods plant-1 (16.28) was recorded the in bari jharsheem-1 had been sown on 30 november which was statistically similar to that of same sowing with variety bari jharsheem-2. the lowest number of pods plant-1(6.45) was obtained in bari jharsheem-2 sown on 30 december due to high temperature. it could be noted that 30 december sown plants experienced high temperature (fig.1) during flowering period which caused fewer flower. the flowers were weathered and dried. 30 november sowing received lower day and night temperature during cropping period that caused longer crop growth duration and ultimately produced more tdm and translocation of more tdm to pods. on the other hand, 30 december sowing received higher day and night temperature that hastened maturity and reduced tdm production and translocation of less tdm to the reproductive organ. pod yield decreased with delay sowing. significantly the highest pod yield (16.77t ha-1) was recorded in bari jharsheem-1 in 30 november sowing. the lowest pod yield (7.34 t ha-1) was produced in bari jharsheem-2 from 30 december sowing. sabale et al. (2010) was also found similar differences in the performance of bush beans under different dates of sowing. the highest yield was obtained from optimum sowing probably due to favourable climate possibly optimum temperature resulting better vegetative growth of the plants which ultimately led to the better flowering, fruit set and increased pod yield, which is in agreement with the findings of mohanty et al. (2001) and nielsen (2002). pod yield was possibly reduced due to increase in temperature over 30 november sowing. pod yield of french bean would be decreased at the rate of 252 kg ha-1 day-1 for 30 november sowing. several researcher found that the decreased yield of french bean due to delay planting (singh and singh 1987; ali 1989). table 3. yield and yield components of different french bean varieties under different sowing dates during 2017-18 treatments plant population (m-2) plant height (cm) pods plant-1 (no.) pod yield (t ha-1) d1  v1 22.00 44.37 13.55 14.84 d1  v2 21.00 40.00 12.89 13.64 d1  v3 21.00 43.63 10.03 9.93 d2  v1 22.00 45.93 16.28 16.77 d2  v2 21.00 41.33 15.27 15.44 d2  v3 21.00 44.27 11.33 10.86 d3  v1 21.33 39.00 14.16 14.67 d3  v2 22.33 38.50 13.53 13.13 d3  v3 22.33 36.29 9.97 10.22 d4  v1 21.67 29.23 11.23 12.50 d4  v2 20.67 25.47 6.45 7.34 d4  v3 21.33 28.67 7.51 8.82 lsd (0.05) ns 4.78 5.99 4.55 cv (%) 5.10 1.824 1.23 0.973 v1 = bari jharsheem-1, v2 = bari jharsheem-2, v3 = bari jharsheem-3, d1 = 15 november, 30 november, d2 = 15 december, d4 = 30 december conclusion french bean varieties sown on november to december showed variability in respect of the flowering, flowering duration, number of pods setting and pod about:blank#10033_b phenology, growth and pod yield of french bean 27 yield. but november sowing would be the optimum time for getting maximum pod yield from bari jharsheem-1. references ali, m. 1989. response of frenchbean genotypes to planting dates during winter season. indian j. pulses res. 2(1): 59-63. fisher, n. m. 1980. the effect of time on planting on four beans (phaseolus vulgaris) genotypes in kenya. j. agric. sci. cambodia. 59(2): 401-408. gross, y. and j. kigel. 1994. differential sensitivity to high temperature of stages in the reproductive development of common bean (phaseolus vulgaris l.). field crops. res. for pollinating insects. acta horti. 288: 321325. heitholt, j. j., d. b. egli and leggett, j. e. 1986. characteristics of reproductive abortion in soybean. crop sci. 26: 589-595. ibarra–perez, f. j., d. barnhart, b. ehdaie, k. m. knio and j. g. waines. 1999. effects of insect tripping on seed yield of common bean. crop. sci. 39: 428-433. kay, d. e. 1979. haricot bean (phaseolus vulgaris l .) crop and produc. digest no. 3-food legumes. p.127. mohanty, s. k., b. baisakih, u. k. dikshit and b. bhol. 2001. kalamung, a promising local mungbean cultivar. environ. ecol. 16(1): 222-223. mouhouche, b., f. ruget and r. delécolle. 1998. effects of water stress applied at different phonological phases yield components of dwarf bean (phaseolus vulgaris l.). agron. 18: 197-205. nonnecke, r. vegetables production. van notrand reinhold. new york, usa, 1989. rangaswamy, g. (1975). diseases of crop plants in india. prentice hall of india pvt. ltd., new delhi. rashid, m. m. 1999. shabjibiggayan (in bengali). rashid pub. house, 94, old dohs, dhaka-1206. pp. 418431. sabale, r. n., s. b. wani and t. d. dalvi (2010). evaluation of sowing time for rabi french bean and validation by dssat-3.5. j. maharashtra agri. univ. 35(3):480-482. savin, r. and m. e. nicolas. 1996. effect of short periods of drought and high temperature on grain growth and starch accumulation of two malting barley cultivars. australian j. plant physiol. 23: 201-210. singh, r. c. and m. singh 1987. response of french bean (phaseolus vulgaris l.) varieties to sowing time. haryana agric. univ. j. res. 17: 266-268. szyrmer, j., j. dembińska and a. wawer. 1992. przebieg wegetacji i zmiennoś ćcechuż ytkowychodmian i form phaseolus vulgaris l. / the vegetation pattern and variability of useful traits of cultivars and forms of phaseolus vulgaris l. biul. inst. hod. aklim. rośl. 180: 229 -239. thavaprakaash, n., r. jagannathan, k. velayudham and l. gurusamy. 2007. seasonal influence on phenology and accumulated heat units in relation to yield of baby corn. int. j. agric. res. 2: 826-831. wallace d. h., p. a. gniffke, p. n. masaya and r. w. zobel. 1991. photoperiod, temperature, and genotype interaction effects on days and nodes required for flowering of bean. j. amer. soc. hort. sci. 116(3): 534-543. 26 kakon et al. wilczek m. and m. ćwintal. 2003. wpływ warunków pogodowych i glebowych na długoś ć kwitnienia nasiennej koniczyny czerwonej. / the in fluence of weather and soil conditions on red clover flowering length. ann. univ. mariae curie-skłodowska, sect. eee hortic. 13: 263 -269. vange, t. and i. u. obi. 2006. effect of planting date on some agronomic traits and grain yield of upland rice varieties at makurdi, benue state, nigeria. j. sustain. dev. agric. env. 2(1): 1-9 (issn 0794-8867). introduction materials and methods bangladesh agron. j. 2021, 24(1): 57-70 influence of sowing dates on the phenological development, growth and yield of white maize genotypes s. akhtar1, m.j. ullah2, a. hamid3, m.s. islam2, m.k.u. ahamed4 and s.m. masum2 1krishi gobeshona foundation, 2department of agronomy, 4department of botany, sher-e-bangla agricultural university, 3department of agronomy, bangabandhu sheikh mujibur rahman agricultural university corresponding e-mail: shahrina.akhtar@gmail.com (received: 05 march 2021, accepted: 14 march 2021) keywords: white maize, genotypes, sowing date, phenology, performance abstract the experiment was conducted at the sher-e-bangla agricultural university (90o22 e, 23o 41 n), dhaka, bangladesh in rabi (winter) season of 2017-2018 to study the effects of sowing date on growth and yield of four white maize genotypes, viz. psc-121, yangnuo-7, yungnuo-30 and changnuo-6. sowing dates were november 26, december 11, and december 26. data were collected on different phenological growth stages, dry matter, physiological attributes, yield, and yield attributes. a delay in sowing date delayed the time required for seedling emergence, to reach the 6-leaf collar, maturity stage, and also reduced yield. the planting of psc-121 in november 26 gave the highest dry matter plant-1, the number of grains cob-1, and 100grain weight that resulted in the highest grain yield (11.65 t/ha) of the genotype. introduction in bangladesh, maize covers an area of about 0.304 m ha with a production of over 2 mt per year which is almost exclusively used as livestock feed. however, white maize covers only 12% of worldwide which is regularly grown for providing grains for human ingestion (ullah et al., 2017). the interest of consumers is increasing, in white maize particularly in those regions where maize is the main cereal for food. preferences for endosperm color depend on the local traditions, though white is generally chosen for human food. today, white maize is preferred for human consumption because the degradation of carotenoids during baking or frying causes a strong aroma and flavor (malver et al., 2008). maize can be grown all over the country. it is a fast-growing crop that grows well with a minimum temperature of 10ºc and a maximum of 30ºc. however, a significant decrease in maize yield with delayed sowing was reported by anapalli et al. (2005) and williams ii (2008). identification of suitable high-yielding varieties (hyv) and optimum seeding time are the two key important factors for sustainable maize production (ramankutty, 2002; liaqat et al., 2018). the phenology of corn has been described as the appearance of leaves or leaf collars during the vegetative stage and the accumulation of material in the grain during the reproductive stage. the duration of phenological events changes based on accumulated temperature patterns which are depended on prevailing air temperature. as the relationship between various physical factors of the environment and seasonal changes dictates the phenology of a plant during its life cycle (varma et al., 2014). its adaptation varies in terms of the ability to mature and setting grains. sowing at proper time and selection of good variety are the most important factors for cropping system. to minimize the negative effect of 58 akhtar et al. some abiotic and biotic stress on the plant, sowing date can play a major role in determining the seed yield, quality, seed germination, and understanding whole phenology stages in many regions (koca and canavar, 2014). in bangladesh conditions, maize planted in the late dry season suffers from heat stress during flowering and early grain filling stages which may affect these developmental stages. sometimes drought coupled with heat shock may also affect the crop. since climate change impacts are visible in bangladesh agriculture, it is necessary to look for cereal germplasms that can withstand high temperatures. evaluation of new maize germplasms in terms of adaptive potential under high heat regimes as well as under optimal conditions could open up an avenue for sustaining maize production in bangladesh. it is also necessary to identify the morphological and physiological traits to heat stress of maize genotypes with sowing date. materials and methods the experiment was conducted in the experimental field of sher-e-bangla agricultural university, dhaka-1207, during the rabi season of 2017-2018. the soil was shallow red brown terrace that belongs to the tejgaon soil series under the agro-ecological zone aez-28), madhupur tract (rashid et al., 2018). the experimental area was situated at 23o 41 n latitude and 90o22 e longitude at an elvation of 8.6 meters above sea level (khanam et al., 2016). the average sunshine hours and temperature during the study period are presented in fig. 1. the experiment comprised two factors; varieties: v1 = psc 121, v2 = yangnuo-7, v3 = youngnau30 and v4 = changnuo-6; and sowing date: s1= november 26, s2= december 11 and s3= december 26, 2017. the experiment was laid out in a randomized complete block design (rcbd) with three replications. unit plot size was 2.4 m  3.5 m. the amount of fertilizer in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate, and boric acid was calculated according to bari (2016). the total amount of tsp, mop, gypsum, zinc sulphate, and boric acid and 1/3rd of total urea were broadcasted and incorporated in a plot two days before sowing. the rest of the urea was top-dressed in two equal installments: one at 4-6 leaf stage and another at 10-12 leaf stage (pre-tasseling stage). cow dung was applied @ 5 ton/ha at the time of final land preparation. seeds of white maize genotypes were sown in a line 60 cm  20 cm apart. different intercultural operations such as thinning, weeding, watering, earthing up, etc. were done when necessary. phenological, growth, and yield data were measured. the collected data were analyzed, and the mean differences were compared by least significant difference (lsd) using a computer-operated program statistix 10. fig. 1. line graphs showing the average sunshine hour (a) and total rainfall (b) from november 16 to april 18, 2017 in the study area influence of sowing dates on growth and yield of white maize genotypes 59 results and discussion days to emergence corn emergence (ve stage) is achieved when the coleoptiles reach and break through the soil surface. generally, corn that emerges under favorable conditions can be 4 to 5 days after sowing. the date of emergence is the function of germination time. the genotype and sowing dates and their interactions had a significant effect (figs. 2-4) on days to emergence. the maximum date of emergence was found from changnuo-6 (6 days) which was statistically similar to yungnuo-7 (6 days), and whereas the lowest date of emergence from psc-121 (5 days). crop sown on december 11 recorded the maximum date of emergence which was statistically at par with november 26 sowing. the lowest date of emergence (5 days) was observed from november 26. among the interaction effect, the highest date of emergence was observed from the combination of december 11 sowing with genotype changnuo-6 (6 days), while the lowest date of emergence from november 25 sowing with yungnuo-30 (5 days). the maximum date of emergence under the december 11 sowing was attributed to the maximum date of emergence characters. ali et al. (2018) reported that one of the most vital factors contributing to the yield gap is the sowing of maize on appropriate sowing dates. the delay in sowing date can lead to a linear decrease in grain yields (anapalli et al., 2005). fig. 2. days to emergence of white maize as influenced by varying sowing dates (s1=26 november 2017, 11th december 2017 and 26th december 2017); (lsd5% =0.09) fig. 3. days to emergence of different white maize genotypes (v1=psc-121, v2 =yangnuo-7, v3 = yungnuo-30, v4 = changnuo-6; lsd5% =0.11) fig. 4. days to emergence of white maize as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december; lsd5% =0.19). 60 akhtar et al. days to 6-collar leaf stage (v6) data on the 6-collar leaf stage have been presented in figs. 5-7 and the variety, sowing dates, and their interactions had a significant effect. during this stage, the uppermost ear and tassel were initiated and kernel row numbers were determined. the highest (42.44 days) date to the 6collar leaf stage was found from psc-121 and the lowest (32.11 days) from yungnuo-7. crop sown on december 26 recorded the maximum (40 days) date to 6-collar leaf stage which was statistically at par with may 29 sowing (19 days). the lowest 6-collar leaf (36 days) was observed from july 6. among the interaction effect of white maize varieties and sowing dates the highest days to 6-collar leaf stage (42. days) from the combination of psc-121 with december 26 sowing. the lowest date to 6-collar leaf stage (30 days) was obtained from the treatment combination yungnuo-7 with november 26 sowing. fig. 5. days to 6-collar leaf stage of different white maize genotypes grown across varying sowing dates (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; lsd5% =0.11). fig. 6. days to 6-collar leaf stage of white maize as influenced by varying sowing dates (26 november 2017, 11th december 2017 and 26th december 2017) (lsd5% =0.09). fig. 7. days to 6-collar leaf stage of white maize grown season as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo6; s1=26th november s2=11th december and s3=26th december; lsd5% = 0.19). influence of sowing dates on growth and yield of white maize genotypes 61 days to 10-collar leaf stage (v10) during the v10 growth stages, any management practice that helps reduce plant stress and allows for adequate nutrient levels can help maximize yield potential. ten leaves have formed, the corn stalk elongates, and the tassel rapidly grows during this phase. the variety, sowing dates, and their interactions had a significant effect on days to 10-collar leaf stage (figs. 8-10). the maximum (62 days) date to 10-collar leaf stage was found from yungnuo-30, which was statistically similar to psc-121 (62 days), and the lowest (52. days) date 10-collar leaf was found from yungnuo-7. crop sown on december 26 recorded the highest (59 days) date to 10-collar leaf stage. the lowest (57 days) date to the 10-collar leaf stage was observed from november 26. among the interaction, the highest date to 10-collar leaf stage (63 days) was observed from the combination of psc-121 genotype with december 26 sowing. while the lowest (51 days) date to 10-collar leaf stage was obtained from the treatment combination of yungnuo-7 variety with november 26 sowing. fig. 8. days to 10-collar leaf stage of different white maize genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; lsd5% =0.9). fig. 9. days to 10-collar leaf stage of white maize as influenced by varying sowing dates (s1=26 november, s2= 11th december and s3= 26th december (lsd5% =0.8). fig. 10. days to 10-collar leaf stage of white maize grown as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26 th , s2=11th december and s3=26th december ; lsd5% = 0.16). 62 akhtar et al. days to 12-collar leaf stage (v12) at v12, kernel row determination is almost complete. as the plant nears pollination, soil moisture and nutrient availability become increasingly critical for yield determination. the genotype, sowing dates, and their interactions had a significant effect on days to 12-collar leaf stage (figs. 11-13). the maximum (64 days) date to 12-collar leaf stage was found from yungnuo-30, which was statistically similar to yungnuo-30 (62.44 days) and the lowest (53.89 days) date of emergence from yungnuo-7. crop sown on december 26 recorded the highest (61 days) date to the 12-collar leaf stage. the lowest date of emergence (58 days) was observed from november 26. among the interaction, genotypes and sowing dates, the highest date to 12-collar leaf stage (65 days) was observed from the combination of genotype yungnuo-30 with december 26 sowing. while the lowest (53 days) date to the 12-collar leaf stage was obtained from the treatment combination of genotype yungnuo-7 with november 26 sowing. fig. 11. days to 12-collar leaf stage of different white maize genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; lsd5%= 0.9). fig. 12. days to 12-collar leaf stage of white maize as influenced by varying sowing dates (s1=26 november, 11th december and 26th december) (lsd5% =0.8). fig. 13. days to 12-collar leaf stage of white maize grown as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s2=26th december; lsd5% = 0.16). influence of sowing dates on growth and yield of white maize genotypes 63 plant height the variety, sowing dates, and their interactions had a significant effect on plant height in figs. 14-16. the highest plant height (203.47 cm) was found from psc-121 and the lowest (158.02 cm) from yungnuo-7. crop sown on november 26 was recorded the highest plant height (201.03 cm). the lowest plant height (158.25 days) was observed from december 26. among the interaction, the highest plant height (217.67 cm) was observed from the combination of psc-121 with november 26 sowing while the lowest date of plant height (137.33 cm) from the treatment combination of genotype yungnuo-7 with december 26 sowing. fig. 14. plant height of different white maize genotypes (v1=psc-121, v2= yangnuo-7, v3= yungnuo-30, v4= changnuo-6; lsd5% 0.09 grown in rabi 2017-2018 season. fig. 15. plant height of white maize as influenced by varying sowing dates (s1=26 november, s2=11 december and s3=26 december) (lsd5% = 0.08). fig. 16. plant height of white maize as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december; lsd5% =017). 64 akhtar et al. leaf area per plant leaf area per plant varied depending upon the growth stages, the smallest (0.0177-0.0341 m2 at 30 das while the greatest (0.6763-0.7600 m2) at maturity (table 1) with the advancement of plant age the leaf area of the individual plant progressively increased. at the earlier stages, the leaf area of the treatments was inconsistent while at the later stages the effect of the treatments was found to be conspicuous. at the maturity, the leaf area in most of the cases was found to be greater with the changnuo-1 which at the latest stage ranged 0.6843-0.7536. the leaf area in most of the cases was found to be greater with the second sowing which at the latest stage ranged from 0.7172-0.7214. it was the greatest with the latest sowing at 90 das (days after sowing) at which it ranged from 0.8035-0.8229. at the maturity, the leaf area in most of the cases was found to be greater with the interaction effect of changnuo-1 and december 26 and at this stage, the leaf area per plant ranged 0.6841-0.7600 m2. table 1. leaf area per plant of white maize grown in rabi 2017-18 season as influenced by genotypes and varying sowing dates treatments leaf area plant-1 (m2) at different days after sowing 30 das 45 das 60 das 75 das 90 das at harvest effect on variety v1 0.0194 0.0324 0.1789 0.3469 0.8391 0.7113 v2 0.0235 0.0422 0.2607 0.4989 0.7580 0.6843 v3 0.0246 0.0399 0.2277 0.4915 0.8690 0.7536 v4 0.0248 0.0373 0.2091 0.4315 0.7770 0.7286 lsd 5% 1.60 0.03 0.30 0.10 0.08 0.09 effect on sowing dates s1 0.0216 0.0406 0.2103 0.4311 0.8061 0.7172 s2 0.0233 0.0372 0.2259 0.4095 0.8035 0.7198 s3 0.0243 0.0361 0.2210 0.4861 0.8229 0.7214 lsd 5% 1.39 0.03 0.26 0.08 0.08 0.07 interaction effect of variety and sowing date v1s1 0.0161 0.0298 0.1502 0.3147 0.8576 0.7068 v1s2 0.0206 0.0375 0.1911 0.3481 0.7956 0.7083 v1s3 0.0216 0.0299 0.1953 0.3780 0.8642 0.7187 v2s1 0.0263 0.0507 0.2787 0.5290 0.7334 0.6841 v2s2 0.0181 0.0374 0.2048 0.4064 0.7660 0.6926 v2s3 0.0262 0.0387 0.2986 0.5614 0.7747 0.6763 v3s1 0.0219 0.0459 0.2041 0.5292 0.8725 0.7481 v3s2 0.0341 0.0420 0.3136 0.4778 0.8670 0.7528 v3s3 0.0177 0.0318 0.1654 0.4676 0.8677 0.7600 v4s1 0.0222 0.0360 0.2083 0.3515 0.7607 0.7297 v4s2 0.0206 0.0319 0.1940 0.4057 0.7853 0.7253 v4s3 0.0317 0.0441 0.2249 0.5373 0.7851 0.7307 lsd(0.05) 0.078 0.06 0.52 0.17 0.15 0.15 cv (%) 18.4 15.29 19.82 3.47 1.68 1.93 note: (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december influence of sowing dates on growth and yield of white maize genotypes 65 stover dry weight per plant from 30 to 90 das dry weight per plant increased progressively with advances of growth stages from 30 days after sowing up to maturity. at 30 das each plant accumulated dry weight at around 20 g in the season. the dry weight gradually increased and attained 79-80 g at 75 (almost flowering) and then finally reached around 120.26 g at maturity. it was apparent that the dry weight was somewhat inconsistent with sowing dates. table 2. dry weight per plant at different growth stages of white maize genotypes under varying sowing dates during rabi 2017-18 up to 90 das treatments growth stages 30 das 45 das 60 das 75 das 90 das effect on variety v1 20.42 31.24 54.15 81.63 122.45 v2 20.70 29.16 50.40 76.64 110.37 v3 20.66 29.99 54.56 80.38 122.45 v4 20.78 29.99 54.56 80.38 122.03 lsd 5% 1.99 1.99 2.30 2.22 2.12 effect on sowing dates s1 20.74 30.93 53.42 79.34 120.26 s2 20.64 29.68 53.42 80.28 119.64 s3 20.54 29.68 53.42 79.66 118.08 lsd 5% 1.33 1.35 1.35 1.23 1.67 interaction effect of variety and sowing date v1s1 20.12 31.24 54.98 81.22 123.70 v1s2 20.62 29.99 53.73 82.47 121.20 v1s3 20.52 32.49 53.73 81.22 122.45 v2s1 20.97 29.99 49.98 76.22 111.21 v2s2 20.15 28.74 51.23 77.47 111.21 v2s3 20.97 28.74 49.98 76.22 108.71 v3s1 20.87 31.24 54.98 79.97 122.45 v3s2 20.93 29.99 53.73 81.22 123.70 v3s3 20.18 28.74 54.98 79.97 121.20 v4s1 20.99 31.24 53.73 79.97 123.70 v4s2 20.87 29.99 54.98 79.97 122.45 v4s3 20.49 28.74 54.98 81.22 119.95 lsd(0.05) 0.74 0.76 0.50 0.88 0.98 cv (%) 1.34 1.23 1.34 1.34 1.01 note: (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december relationship of dry weight with leaf area linear regression was made to find relations of dry weight with the leaf area irrespective of genotype and sowing dates. it was observed that the leaf area had a moderate effect on the dry weight showing the regression coefficient value of 0.4047 (fig. 17). as the result of changing sowing date, maize crop receives a different level of radiation as well as thermal temperature and period also vary. cirilo and andrade (1994) were found that late sowing of crops decreased their 66 akhtar et al. growth and development because less amount of solar radiation was captured by the crop during emergence to the silking stage. fig.17. relationship of dry weight with leaf area. days to physiological maturity the variety, sowing dates, and their interactions had a significant effect on days to physiological maturity (figs. 18-20). the highest (134 days) date physiological maturity was found from psc121 and whereas the lowest (113 days) date from changnuo-6 of physiological maturity. crop sown on december 26 recorded the highest (132 days) date of physiological maturity while the lowest (126 days) was observed from november 26 sowing. among the interaction, s the highest (141 days) date of physiological maturity was observed from the combination of genotype psc-121 with december 26 sowing. while the lowest (111.00 days) was obtained from the treatment combination of genotype yungnuo-7 with november 26 sowing. sangoi (1993) was found hybrid maize planted during earlier sowing date elongated growth period of more than 2 weeks than planted in delayed date. fig. 18. days to physiological maturity of different white maize genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo6; lsd5% =0.08 grown in rabi 2017-2018 season. fig. 19. days to physiological maturity of white maize as influenced by varying sowing dates (s1=26 november, s2=11th december and s3=26th december) (lsd5% =0.07). influence of sowing dates on growth and yield of white maize genotypes 67 fig. 20. days to physiological maturity as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, 11th december and 26th december; lsd5% =0.1). number of grain row per cob the variety, sowing dates, and their interactions had a significant effect on the number of grain rows per cob (table 3). table 3. yield attributes of white maize genotypes under varying sowing dates during rabi 2017-18 treatments number of grain row per cob number of grains per row on a cob number of grains per cob 100grain weight effect on variety v1 13.67 22.11 301.84 31.16 v2 11.44 16.07 183.72 26.25 v3 13.50 20.94 282.55 31.38 v4 13.56 20.24 274.50 32.80 lsd(0.05) 0.68 0.87 0.96 1.00 effect on sowing dates s1 13.08 21.11 278.75 32.38 s2 12.83 20.02 258.45 30.01 s3 13.67 18.34 244.75 28.80 lsd(0.05) 0.58 0.75 0.83 0.87 interaction effect of variety and sowing date v1s1 14.00 23.10 323.40 33.02 v1s2 13.00 23.11 300.43 30.43 v1s3 14.00 20.12 281.68 30.04 v2s1 11.33 16.80 190.34 28.98 v2s2 11.33 16.54 187.40 26.50 v2s3 11.67 14.86 173.42 23.27 v3s1 13.33 22.40 298.59 33.43 v3s2 13.67 20.76 283.79 30.57 v3s3 13.50 19.65 265.28 30.13 v4s1 13.67 22.14 302.65 34.10 v4s2 13.33 19.67 262.20 32.54 v4s3 13.67 18.92 258.64 31.76 lsd(0.05) 1.17 1.51 1.66 1.74 cv (%) 5.41 1.38 1.75 3.38 note: (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december 68 akhtar et al. the highest (13.67) number of rows was found from the genotype psc-121 whereas the lowest (11.44) number of rows from yungnuo-7. crop sown on december 26 recorded the highest (13.67) number of row while lowest (12.83) number of rows from december 11 sowing. among the interaction, the highest number of rows (14) was observed from the combination of psc121 genotype and december 26 while the lowest number of rows (11.33) from genotype yungnuo-7 with november 26 sowing. number of grains per row on a cob the variety, sowing dates, and their interactions had a significant effect on the number of grains per row on a cob (table 3). the highest (22.11) number of grains per row was found from psc121 and whereas the lowest (16.07) from yungnuo-7. crop sown on november 26 recorded the highest number of grains per row (21.11) while the lowest (18.38) number of grains per row from december 26 sowing. among the interaction effect, the highest number of grains per row (23.11) was observed from the combination of psc-121 genotype with december 11 sowing while the lowest (14.86) from the treatment combination of genotype yungnuo-7y with december 26 sowing. number of grains per cob the variety, sowing dates, and their interactions had a significant effect on the number of grains per cob (table 3). the highest (301.84) number of grains per cob was found from genotype, psc-121 and whereas the lowest (183.72) from yungnuo-7. crop sown on november 26 recorded the highest (278.75) number of grains per while the lowest number of grains per cob (244.75) from december 26 sowing. among the interaction effect, the highest number of grains per cob (323.4) was observed from the combination of genotype psc-121 with november 26 sowing. while the lowest number of grains of cob (173.42) was obtained from genotype yungnuo-7 with december 26 sowing. grain number per cob, as well as flower distribution, had been adversely affected by the delay in sowing dates (otegui and melon, 1997). 100grain weight the variety, sowing dates, and their interactions had a significant effect on 100-seed weight (table 3). the highest 100-seed weight (32.8 g) was found from changnuo-6 and whereas the lowest (26.25 g) from genotype yungnuo-7 (26.25 g). crop sown on november 26 was recorded the highest (32.38 g) number of grains per cob while the lowest weight (28.80 g) from december 26 sowing. among the interaction, the highest weight (34.10 g) was observed from the combination of changnuo-6 genotype with november 26 sowing. while the lowest weight (23.27 g) was obtained from the treatment combination of genotype (yungnuo-7) with december 26 sowing. killi and altanbay (2005) also observed that seed weight was significantly affected by the sowing dates. grain yield proper selection of sowing dates can optimize maize yield. the variety, sowing dates, and their interactions had a significant effect on grain yield per hectare (figs. 21-23). the highest (11.48 t ha-1) grain yield was found from psc-121 and whereas the lowest (7.87 t ha-1) from genotype (changnuo-6). crop sown on november 26 recorded the highest (10.14 t ha-1) grain yield while lowest weight (9.97 t ha-1) from december 26 sowing. among the interaction effect, the highest (11.65 t ha-1) grain yield was observed from the combination of psc-121 genotype with november 26 sowing while the lowest (7.81 t ha-1) from the treatment combination genotype (yungnuo-7) with december 26 sowing. considerable yield declined as a result of sowing too influence of sowing dates on growth and yield of white maize genotypes 69 late as reported in maize (meza et al., 2008). maize yield response to sowing date is very similar in different years and locations attributing yield benefits to early sowing (good et al., 2015; shrestha et al., 2016). fig. 21. per hectare seed yield of different white maize genotypes (v1=psc121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; lsd 5% = 0.1. fig. 22. per hectare seed yield of white maize as influenced by varying sowing dates (s1=26 november, s2=11th december, and s3=26th december) (lsd5% = 0.08. fig. 23. per hectare seed yield of white maize as influenced by varying sowing dates and genotypes (v1=psc-121, v2=yangnuo-7, v3= yungnuo-30, v4= changnuo-6; s1=26th november, s2=11th december and s3=26th december; lsd5% = 0.17. conclusion from the present study it may be concluded that the genotype psc-121 gave the highest yield and yield attributes when sown on november 26. this information may be useful for maize growers and researchers. 70 akhtar et al. references ahmmed, t., m.j. ullah, m.a. mannan and m.s. akter. 2020. performance of white maize under different spacing and integrated fertilizer management. asian plant res. j. 6(2): 23-32. ali, w., m. ali, z. ahmad, j. iqbal, s. anwar, m.h. khan and a. kamal. 2018. influence of sowing dates on varying maize (zea mays l.) varieties grown under agro-climatic condition of peshawar, pakistan. eur. j. exp. biol. 8(6): 36. anapalli, s., s.l. ma, d.c. nielsen, m.f. vigil and l.r. ahuja. 2005. simulating planting date effects on corn production using rzwqm and ceres maize models. agron. j. 17: 58-71. bari (bangladesh agricultural research institute). 2016. bari annual report 2015-16. pp.27-38. cirilo, a.g. and f.h. andrade. 1994. sowing date and maize productivity: i. crop growth and dry matter partitioning. crop sci. 34: 1039-1043. good, d., j. newton and s. irwin. 2015. early planting and 2015 corn yield prospects: how much of an increase? farmdoc daily, p.5. khanam, m., m.s. islam, m.h. ali, i.f. chowdhury and s.m. masum. 2016. performance of soybean under different levels of phosphorus and potassium. bangladesh agron. j. 19(1): 99-108. killi, f. and s.g. altunbay. 2005. seed yield, oil content and yield components of confection and oil seed sunflower cultivars (helianthus annuus l.) planted on different dates. int. j. agric. biol.7: 21-24. koca, y.o. and o. canavar. 2014. the effect of sowing date on yield and yield components and seed quality of corn (zea mays l.). scientific papers. series a. agron. lvii: 227-231. liaqat, w., m. akmal and j. ali. 2018. planting dates effect on production of high yielding maize varieties. sarhad j. agri. 34(1): 102-113. malvar, r.a., p. revilla, j. moreno-gonzález, a. butrón, j. sotelo and a. ordás. 2008. white maize: genetics of quality and agronomic performance. crop sci. 48: 1373–1381. meza, f.j., d. silva and h. vigil. 2008. climate change impacts on irrigated maize in mediterranean climates: evolution of double cropping as an adaptation alternative. agric. syst. 98: 21-30. otegui, m.e. and s. melon. 1997. kernel set and flower synchrony within the ear of maize: i. sowing date effects. crop sci. 37: 441-447. ramankutty, n., j.a foley, j. norman and k. mcsweeney. 2002. the global distribution of cultivable lands: current patterns and sensitivity to possible climate change. global ecol. biogeogr. 13: 377-392. sangoi, l. 1993. aptidao dos campos de langes (sc) para producao de milho em diferentes epocas de semeadura. pesquira agropecuaria brasileira. brasilia. 28: 51-63 shrestha, u., l.p. amgain, t.b. karki, k.r. dahal and j. shrestha. 2016. effect of sowing dates and maize cultivars in growth and yield of maize along with their agro-climatic indices in nawalparasi, nepal. j. agrisearch. 3(1): 57-62. ullah, m.j., m.m. islam, k. fatima, m.s. mahmud, j. rahman and s. akhter. 2017. comparing modern varieties of white maize with local races: ear characters. j. expt. biosci. 8(2): 49-58. varma, v.s., k.k. durga and p. neelima. 2014. effect of planting date on maize grain yield and quality: a review. review plant studi.1(2): 26-38. williams ii, m.m. 2008. sweet corn growth and yield responses to planting dates of the north central united states. hort. sci. 43: 1775-1779. bangladesh agron. j. 2022, 25(1): 97-103 sustainable soil management for nutrition sensitive agriculture through micronutrient inclusion in boro rice cultivation p.k. biswas, s. samia and s. shome department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh corresponding e-mail: parimalbiswas@hotmail.com (received: 25 may 2022, accepted: 11 july 2022) keywords: zinc, boron, organic manure, foliar spray, rice abstract the experiment was conducted in boro season, 2020-21 to compare the performance of fortified rice variety brri dhan84 with non-fortified mega variety brri dhan89 and their suitable combinations for maximum growth and yield. treatments were: two rice variety viz., i) brri dhan84 (v1) and ii) brri dhan89 (v2) in the main plot and seven different fertilizer management viz., i) no fertilizer (f1), ii) recommended npks (rfd) with zn as basal (f2), iii) rfd + zn as foliar at anthesis (f3), iv) rfd + zn & b as foliar at anthesis (f4), v) 50% rfd + 50% cowdung as basal (f5), vi) 50% rfd + 50% cowdung + zn & b as basal (f6) and vii) 50% rfd + 50% cowdung as basal + zn & b as foliar at anthesis (f7) in the sub-plot. the experiment was laid out in a split-plot design having 3 replications. no significant variations observed between the two varieties for almost all the studied characters except filled grains panicle-1 where the variety brri dhan89 showed higher number of grains (116.14) than the other variety. foliar application of zinc and born (f4) gave the highest plant height (102.54 cm), effective tillers hill-1 (12.83) that similar (13.00) with f2 (recommended npks with zn as basal), panicle length (25.91 cm), 1000-grain weight (23.58 g), grain yield (7.67 t ha-1), biological yield (14.85 t ha-1) and harvest index (51.69%). the interaction of v2f4 and v1f4 resulted superior response for almost all the studied parameters. foliar application of zinc and boron (f4) along with rfd increased 8.79 and 27.45% yield in brri dhan89 compared to that of foliar (f3) and basal (f2) application of zinc, respectively that was 17.11 and 26.77% for the other rice variety brri dhan84. introduction rice (oryza sativa l.) is the staple food in bangladesh and accounting for approximately 78 percent of the country’s total net cropped areas cultivation. the country achieves an autarky to meet up the rice demand for its 169.04 million peoples from 11.55 million hectares of cultivated gross area (kabir et al., 2020; nasim et al., 2021). rice provides about 75% of the calories and 55% of the protein in the average daily diet of the people of bangladesh and contributes 18% to gdp (bhuiyan et al., 2002). grain quality has always been an important consideration in rice variety selection and development. fortified rice varieties are rich in micronutrients like zinc and iron. nutrition-sensitive agriculture is a food-based approach to agricultural development that puts nutritionally rich foods to overcome malnutrition and micronutrient deficiencies. micronutrients provided by soils are crucial for plant development and growth. nutrient mining occurs when crops take out a high proportion of the nutrients available in the soil, leaving a nutrient imbalance that threatens the sustained provision of food and ecosystem services. furthermore, good nutrition is achieved through healthy and balanced diets, composed of foods with adequate nutritional composition. exploring different soil management practices can help increase the nutritional content of crops, as many are directly affected by the nutritional status of the soil. fao and itps (2015) have demonstrated the extent of soil fertility has suffered from unsustainable management practices. rates of malnutrition in bangladesh are among the highest in the world. more than 54 %t of preschool-age children, equivalent to more than 9.5 million children, are stunted, 98 biswas et al. 56 percent are underweight and more than 17 % wasted. bangladeshi children also suffer from high rates of micronutrient deficiencies, particularly vitamin a, iron, iodine and zinc deficiency. improving nutrition through soils can have a significant impact on malnutrition in bangladesh. this populationwide zinc deficiency is one key reason why stunting affects 41% of children in bangladesh aged under five years (rahman et al., 2016). cultivation of mv and hybrid varieties of different crops is deteriorating soil fertility status of most bangladesh soil day by day due to exhaustive nature of those varieties. as a consequences new nutrient deficiency in soil is emerging. chronologically n, p, k, s, zn and b deficiencies have arisen in bangladesh soils (islam, 2008). some reasons of micronutrient deficiency in bangladesh were highlighted by jahiruddin and islam (2014) and those are organic matter depletion, unbalanced use of fertilizers, minimum or no use of manure, high cropping intensity, high ph (e.g. calcareous soils), nutrient leaching and light textured soils (jahiruddin and islam, 2014). rice bio-fortified with zinc (zinc rice) could help the critical gap by delivering up to 90% of their daily dietary requirements of zinc naturally (bashar and miah, 2016). rice var. brri dhan84 composes of zinc which may scale up its potentially-competitive agronomic characteristics along with another non-fortified variety. kaer et al. (2020) also reported that the zinc enriched brri dhan84 is a superb variety for cultivating in the dry (boro) season and farmers can be economically benefited. the study was therefore undertaken to compare the performance of fortified rice var. brri dhan84 with brri dhan89 and to determine the suitable fertilizer management. materials and methods the experiment was conducted during the december 2020 to june 2021 at the agronomy field of shere-bangla agricultural university, dhaka. the seeds of boro rice var. brri dhan84 and brri dhan89 were used as plant materials and the seeds were collected from bangladesh rice research institute (brri), joydebpur, gazipur. the basal recommended dose i.e., urea, tsp, mop, zn and b and with cowdung were used in the experiment as per treatment. the whole amount of all fertilizers except urea along with cowdung was applied as a basal dose during final land preparation. the urea fertilizer was applied as four equal splits at 10, 20, 30 and 40 days after transplanting (dat). the foliar application of zn and b were applied as per treatment before anthesis. the sprouted seeds of two rice varieties were sown in the nursery bed on 05 december, 2020 from which 35 days old seedlings were transplanted in the main field on 10 january, 2021 maintaining 20 cm x 20 cm spacing. the experiment was laid out in a split-plot design with three replications. the treatments were two variety viz., i) brri dhan84 (v1) and ii) brri dhan89 (v2) in the mainplot and seven different fertilizer management viz., i) no fertilizer (f1), ii) recommended npks (rfd) with zn as basal (f2), iii) rfd + zn as foliar at anthesis (f3), iv) rfd + zn & b as foliar at anthesis (f4), v) 50% rfd + 50% cowdung as basal (f5), vi) 50% rfd + 50% cowdung + zn and b as basal (f6) and vii) 50% rfd + 50% cowdung as basal + zn and b as foliar at anthesis (f7) in the sub-plot. water was ensured to the field throughout the growing season up to 10 days before harvesting. two hand weedings were done for all the treatments on 30 and 45 dat. the field was infested by different insects and diseases those controlled by applying appropriate ways in time. five hills per plot was randomly selected for collecting plant height, number of tillers hill-1 and spad value at stipulated dates. the yield and yield attributes were recorded. the grain yield and straw yield were recorded at 12 % moisture level. statistical analyses were done by using the crop stat computer package and the mean differences among the treatments were compared by least significant difference test at 5 % level of significance following gomez and gomez (1984). results and discussion effect of variety sustainable soil management for nutrition sensitive agriculture 99 all the studied characters showed non-significant variation between the two varieties except number of filled grains panicle-1 where brri dhan89 (116.14) showed higher response compared to that of brri dhan84 (89.47) (table 1 and table 2). the mega var. brri dhan89 resulted 29.81% higher number of filled grains panicle-1 than the other biofortified variety brri dhan84. numerically the variety brri dhan89 showed 7.36% higher grain yield than brri dhan84. similar variation of filled grains panicle-1 among rice varieties was also reported by khatun et al. (2020).the number of grains panicle-1 is mainly determined by the panicle architecture, including panicle length and the number and length of primary, secondary and higher order branches (sakamoto and matsuoka, 2008; kovi et al., 2011). table 1. varietal and fertilizer response on different crop characters of boro rice treatments plant height (cm) effective tillers hill-1 (no.) panicle length (cm) filled grains panicle-1 (no.) unfilled grains panicle-1 (no.) variety v1 96.05 12.14 25.36 89.47b 18.43 v2 97.60 10.86 26.09 116.14a 16.71 lsd(0.05) ns ns ns 13.394 ns cv (%) 5.38 14.51 4.92 9.81 17.54 fertilizer management f1 86.74d 9.17c 24.75b 96.50ab 13.83c f2 99.40abc 13.00a 25.49ab 98.83ab 21.17ab f3 99.73ab 12.83a 25.75a 108.17ab 18.50abc f4 102.54a 12.83a 25.91a 105.67ab 22.83a f5 97.67bc 11.50ab 25.93a 105.33ab 16.17bc f6 94.44c 10.33bc 26.14a 92.33b 14.83c f7 97.25bc 10.83abc 25.91a 112.83a 15.67c lsd(0.05) 4.297 2.183 1.020 20.307 6.284 cv (%) 3.72 15.93 3.33 16.58 30.01 interaction v1f1 84.19e 9.67cde 24.25c 85.33cde 11.33d v1f2 100.14ab 14.00a 25.24bc 76.00de 26.67a v1f3 97.77abc 13.00ab 25.58abc 96.67a-e 17.00bcd v1f4 102.02ab 12.67abc 26.09ab 92.00b-e 24.33ab v1f5 98.23abc 13.67a 25.71ab 97.00a-e 15.00cd v1f6 92.81cd 10.33b-e 25.43abc 75.00e 16.33bcd v1f7 97.20abc 11.67a-e 25.22bc 104.33a-d 18.33a-d v2f1 89.29de 8.67e 25.66abc 107.68abc 16.33bcd v2f2 98.65abc 12.00a-d 25.73ab 121.67a 15.67bcd v2f3 101.70ab 12.67abc 25.92ab 119.67ab 20.00a-d v2f4 103.05a 13.00ab 25.73ab 119.33ab 21.33abc v2f5 97.11abc 9.33de 26.15ab 113.67abc 17.33bcd v2f6 96.08bc 10.33bcde 26.84a 109.67abc 13.33cd v2f7 97.29abc 10.00bcde 26.59ab 121.33a 13.00cd lsd(0.05) 6.077 3.088 1.442 28.719 8.887 cv (%) 3.72 15.93 3.33 16.58 30.01 v1 = brri dhan84, v2 = brri dhan89, f1 = no fertilizer, f2 = rfd with zn as basal, f3 = rfd with zn as foliar, f4 = rfd with zn and b as foliar, f5 = 50% rfd & 50% cowdung, f6 = 50% rfd & 50% cowdung with zn and b as basal, f7 = 50% rfd & 50% cowdung with zn and b as foliar effect of fertilizer management the highest plant height (102.54 cm) at harvest, highest number of effective tillers hill-1 (12.83), 1000grain weight (23.58 g), grain yield (7.67 t ha-1), biological yield (14.85 t ha-1) and harvest index (51.69 %) was recorded from the f4 (rfd with zn and b as foliar) treatment but the lowest result given by f1 (no fertilizer) treatment for most of the studied parameters (table 1 and table 2). application of rfd (npks) as per frg (2018) but zinc and boron as foliar application during anthesis (f4) gave 27.20 % and 74.32 % higher grain yields than f2 (rfd with zn as basal dose) and f1 (no fertilizer) treatments respectively. significant effect of zinc on plant height of rice was reported by uddin et al. (1997), https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6514245/#b41 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6514245/#b21 100 biswas et al. effective tillers hill-1 by rahman et al. (2008), grain yield by islam et al. (1997), wasaya et al. (2017) and azad (2018) and straw yield by islam et al. (1997). interaction of variety and fertilizer management the treatment combination of v2f4 (brri dhan89 and rfd with zn and b as foliar application) showed the highest plant height (103.05 cm), grain yield (7.80 t ha-1)and biological yield (15.31 t ha-1) compared to that of other interactions whereas the highest number of effective tillers hill-1 (14.00) by v1f2, panicle length (26.84 cm) by v2f6, number of filled grains panicle-1 (121.67) by v2f2, number of unfilled grains panicle-1 (26.67) by v1f2, 1000-grain weight (23.83 g) by v2f6, straw yield (8.11 t ha-1) by v2f3 and harvest index (52.36 %) by v1f4 treatment combinations (table 1 and table 2). the lowest parameters were recorded from v1f1 (brri dhan84 and no fertilizer application) interactions. recommended fertilizer dose (rfd) with zinc and boron as foliar spray (f4) gave 76.06 % and 72.71 % higher yield compared to their respective control (f1) of brri dhan89 (v2) and brri dhan84 (v1) respectively whereas 27.45 % and 26.77 % higher than f2 (rfd with zinc as basal dose). zinc being essential nutrient plays a significant role in stomatal regulation and reducing the tensions of less water by creating ionic balance in plants system (baybordi, 2006) and is involved in various physiological processes such as synthesis of protein and carbohydrates (yadavi et al., 2014). similarly, b application improves growth, and enhances stress tolerance in plants and improves grain production (hussain et al., 2012). both zn and b play an important role in the basic plant functions like photosynthesis, protein and chlorophyll synthesis (cakmak, 2008). table 2. grain weight, yield and harvest index of boro rice affected by variety and fertilizer management treatments 1000-grain wt. (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) variety v1 21.64 5.98 6.72 12.70 46.88 v2 22.34 6.42 7.25 13.66 46.79 lsd(0.05) ns ns ns ns ns cv (%) 7.90 9.21 26.19 17.66 10.09 fertilizer management f1 20.57d 4.40e 6.92abc 11.32e 39.05d f2 20.98cd 6.03c 7.31a 13.34cd 45.34c f3 21.42cd 6.80b 7.48a 14.28ab 47.81bc f4 23.58a 7.67a 7.19ab 14.85a 51.69a f5 23.33ab 6.86b 7.01abc 13.87bc 49.45ab sustainable soil management for nutrition sensitive agriculture 101 treatments 1000-grain wt. (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) f6 22.13abc 6.10c 6.63bc 12.73d 47.91bc f7 21.92bcd 5.54d 6.37c 11.91e 46.61bc lsd(0.05) 1.474 0.402 0.636 0.664 2.924 cv (%) 5.62 5.45 7.65 4.23 5.24 interaction v1f1 19.80e 4.36h 6.86bc 11.22g 39.02e v1f2 21.70b-e 5.94ef 6.97bc 12.91de 46.04cd v1f3 20.63de 6.43de 6.85bc 13.27d 48.45a-d v1f4 23.47ab 7.53ab 6.87bc 14.40ab 52.36a v1f5 23.33abc 6.60cd 6.83bc 13.42cd 49.11abc v1f6 20.43de 5.73fg 6.40c 12.12efg 47.30bcd v1f7 22.13a-d 5.29g 6.28c 11.57fg 45.86cd v2f1 21.33cde 4.43h 6.98bc 11.41fg 39.07e v2f2 20.26de 6.12def 7.65ab 13.77bcd 44.63d v2f3 22.20a-d 7.17bc 8.11a 15.28a 47.17bcd v2f4 23.70ab 7.80a 7.50ab 15.31a 51.02ab v2f5 23.33abc 7.13bc 7.18bc 14.32bc 49.78abc v2f6 23.83a 6.47de 6.86bc 13.33d 48.52a-d v2f7 21.70b-e 5.79fg 6.45c 12.24ef 47.35bcd lsd(0.05) 2.084 0.569 0.900 0.940 4.136 cv (%) 5.62 5.45 7.65 4.23 5.24 v1 = brri dhan84, v2 = brri dhan89, f1 = control, f2 = rfd with zn as basal, f3 = rfd with zn as foliar, f4 = rfd with zn and b as foliar, f5 = 50% rfd & 50% cowdung, f6 = 50% rfd & 50% cowdung with zn and b as basal, f7 = 50% rfd & 50% cowdung with zn and b as foliar conclusion based on the results of the study, it may be concluded that the fortified boro rice variety brri dhan84 has the ability to produce similar yield to other mega variety brri dhan89. foliar application of zinc and boron during anthesis along with recommended fertilizer (npks) showed higher yield compared to that of basal application of zinc & with npks. the recommended fertilizer dose (npks) of boro rice with zinc and boron as foliar spray (f4) during anthesis gave 76.06 % and 72.71 % higher yield compared to their respective control (f1) of brri dhan89 (v2) and brri dhan84 (v1) respectively whereas 27.45 % and 26.77 % higher than f2 (npks with zinc as basal dose). however, to reach a specific conclusion and recommendation, experiments with different levels of other micronutrients need to be repeated with more varieties and in different agro-ecological zones. acknowledgement the author gratefully acknowledged the ministry of science and technology, govt. of the people’s republic of bangladesh for providing financial support under special allocation fund to conduct the study. references azad, m.a.k. 2018. effect of foliar and broadcast application of zinc and boron on growth and yield of transplanted aman rice in aez-11 (cv. brri dhan56). ms student, dept. of crop science & technology, rajshahi university, bangladesh. bashar, m.k. and m.a.h. miah. 2016. nutritional security through biofortified zinc rice. the daily star newspaper, 04 february, 2016. 102 biswas et al. baybordi, a. 2006. effect of fe, mn, zinc and cu on the quality and quantity of wheat under salinity stress. j. water soil sci. 17: 140-150. bhuiyan, n.i., d.n.r. paul and m.a. jabber. 2002. feeding the extra millions by 2025: challenges for rice research and extension in bangladesh. keynote paper presented at the national workshop on rice research and extension, bangladesh rice research institute, gazipur, january 29-31, 2002. cakmak, i. 2008. enrichment of cereal grains with zinc: agronomic or genetic biofortification. plant soil. 302: 1–17. fao and itps. 2015. status of the world’s soil resources (swsr) – main report. food and agriculture organization of the united nations and intergovernmental technical panel on soils, rome, italy. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council, farmgate, dhaka. furutani i., s. sukegawa and j. kyozuka. 2006. genome-wide analysis of spatial and temporal gene expression in rice panicle development. plant j. 46: 503–511. 10.1111/j.1365-313x.2006.02703.x. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research 2nd edn. irri, los banos, languna, the philippines, pp.62-74. huang, m., y.b. zou, p. jiang, b. xia, m. ibrahim and h.j. ao. 2011. relationship between grain yield and yield components in super hybrid rice. agric. sci. china, 10: 1537–1544. 10.1016/s16712927(11)60149-1. hussain, m., m.a. khan, m.b. khan, m. farooq and s. farooq. 2012. boron application improves the growth, yield and net economic return of rice. rice sci. 19: 259-262. islam, m.r., t.m. risat and m. jahiruddin. 1997. direct and residual effects of s, zn and b on yield, nutrient uptake in a rice-mustard cropping system j. indian soc. soil sci. 45(1): 126-129. islam, m.s. 2008. soil fertility history, present status and future scenario in bangladesh, bangladesh j. agric. environ. 4: 129-151. jahiruddin, m. and m.r. islam. 2014. project report (2011-2014). requirement of micronutrients for crops and cropping patterns. piu-barc (natp phase-i) project. project id no. 339. kabir, m.s., m. salam, a. islam, m.a.r. sarkar, m. mamun and m. rahman. 2020. doubling rice productivity in bangladesh: a way to achieving sdg 2 and moving forward. bangladesh rice j. 24: 1–47. https://doi.org/10.3329/brj.v24i2.53447. kader, m.a., p.s. biswas, t.l. aditya, m. anisuzzaman, t.k. hore and m.e. haq. 2020. zinc enriched high yielding rice variety brri dhan84 for dry season rice growing areas of bangladesh. asian plant res. j. 6(1): 6-13. https://doi.org/10.9734/aprj/2020/ v6i130117. khatun, s., m.m.a. mondal, m.i. khalil, m. roknuzzaman and m.m.i. mollah 7. 2020. growth and yield performance of six aman rice varieties of bangladesh. asian res. j. agric. 12(2): 1-7. kovi, m.r., x.f. bai, d.h. mao and y.z. xing. 2011. impact of seasonal changes on spikelets per panicle, panicle length and plant height in rice (oryza sativa l.). euphytica 179: 319–331. 10.1007/s10681010-0332-7. li, s., w. li, b. huang, x. cao, x. zhou and s. ye. 2013. natural variation in ptb1 regulates rice seed setting rate by controlling pollen tube growth. nat. commun. 4: 2793. 10.1038/ncomms3793. nasim, m., a. khatun, m. kabir, a. mostafizur, m. mamun and m. sarkar. 2021. intensification of cropping through utilization off allow period and unutilized land resources in bangladesh. bangladesh rice j. 25: 89–100. https://doi.org/10.3329/brj.v25i1.55181 qi, w., f. sun, q. wang, m. chen, y. huang and y.q. feng. 2011. rice ethylene-response ap2/erf factor oseatb restricts internode elongation by down-regulating a gibberellin biosynthetic gene. plant physiol. 157: 216–228. 10.1104/pp.111.179945. rahman, m.t., m. jahiruddin, m.r. humauan, m.j. alam and a.a. khan. 2008. effect of sulphur and zinc on growth, yield and nutrient uptake of boro rice (cv. brri dhan29). j. soil nat. 2(3): 10-15. https://doi.org/10.9734/aprj/2020/%20v6i130117 https://doi.org/10.3329/brj.v25i1.55181 sustainable soil management for nutrition sensitive agriculture 103 rahman, s., t. ahmed, r. ahmed, n. alam, a.m.s. ahmed, s. ireen, i. chowdhury, f. chowdhury and s.m. rahman. 2016. status of zinc nutrition in bangladesh: the underlying associations, j. nutr. sci. 5. 1-9. doi. 10.1017.jns.2016.17. sakamoto, t. and m. matsuoka. 2008. identifying and exploiting grain yield genes in rice. curr. opin. plant biol. 11: 209–214. 10.1016/j.pbi.2008.01.009. uddin, m.n., m.r. islam and a. hossain. 1997. effects of nitrogen, phosphorus and sulphur on aus rice and their residual effect of aman rice in a tidal flooded soil of bangladesh. bangladesh j. agric. sci. 24(1): 61-65. wasaya, a., m.s. shabir, m. hussain, m. ansar, a. aziz, w. hassant and i. ahmad. 2017. foliar application of zinc and boron improved the productivity and net returns of maize grown under rainfed conditions of pothwar plateau. j. soil sci. plant nutr. 17(1): 33-45. yadavi, a., r.s. aboueshaghi, m.m. dehnavi and h. balouchi. 2014. effect of micronutrıents foliar application on grain qualitative characteristics and some physiological traits of bean (phaseolus vulgaris l.) under drought stress. indian j. fund. appl. life sci. 4: 124-131. yu, y., q.f. li, j.p. zhang, f. zhang, zhou and y.z. feng. 2017. laccase-13 regulates seed setting rate by affecting hydrogen peroxide dynamics and mitochondrial integrity in rice. front. plant sci. 8: 1324. 10.3389/fpls.2017.01324. zhang, k., q. song, q. wei, c. wang, l. zhang and w. xu. 2016. down-regulation of osspx1 caused semi-male sterility, resulting in reduction of grain yield in rice. plant biotechnol. j. 14: 1661–1672. 10.1111/pbi.12527. bangladesh agron. j. 2021, 24(1): 109-117 increasing cropping intensity and crop productivity of four crops based mustard-boro-t. aus-t. aman cropping pattern a. barman1, s. shome2, m.r. khatun1, m.m. masud1 and s. akther1 1soil science division, bari, gazipur, bangladesh 2department of agronomy, sau, dhaka, bangladesh corresponding e-mail: alakbarman.sau@gmail.com (received: 19 april 2021, accepted: 01 may 2021) keywords: cropping system; fertilizer; marginal benefit cost ratio; rice equivalent yield; yield abstract a field trial on soil test based (stb) fertilizer doses was conducted during the year of 2017-2018 and 2018-2019 in jashore region (aez-11) to find out the most suitable fertilizer doses for four crop based cropping pattern considering the agronomic feasibility and economic return of the system. the experiment consisted of eight different treatments viz. t1: 100% npksznb (stb), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5:t1 + 25% pk, t6:t1 + 25% npk, t7: 75% of t1, t8: native fertility. randomized complete block design (rcbd) with three replications was followed. data revealed that seed yield of mustard was remarkably influenced by fertilizer treatments while grain yield of other components of the cropping system was not affected significantly by the treatments except control or native fertility. it was observed that 25% more npk over 100% stb dose provided the highest yield of all the component crops. the highest rice equivalent yield (3.34 t ha-1) was recorded from t6 and the lowest (1.88 t ha-1) from t8 treatment. maximum gross return (tk. 420000/ha) and marginal benefit cost ratio (4.08) were also obtained from t6 treatment. so, 25% npk+ 100% stb dose of fertilizer could be followed for productive and remunerative rice based cropping system mustardboro-t. aus-t.aman in aez-11. introduction bangladesh is one of the highest populous countries of the world with the annual growth rate of about 1.37% (bbs, 2019). on the other hand, available agricultural land of bangladesh is decreasing with an alarming rate of about 1% per year (hossain et al., 2014). rate of cropland shifting to non-agricultural land (housing, industry, etc.) is formidable as it is associated with the food security of the country (islam et al., 2018). meeting the challenge of ensuring food security through horizontal expansion of land is not possible due to decrease in agricultural land. so intensifying land use system through multiple cropping or by growing more and more crops on the same piece of land in a calendar year is a promising option to feed this teeming millions. rice based cropping system consisting of boro-fallow-t. aman is a popular cropping pattern of bangladesh (parvin et al., 2017). inclusion of mustard and short duration t. aus variety in this cropping pattern could increase the cropping intensity of our country up to 400% as well as improve the socio-economic condition of the farmer. however, the advantage of including extra crops in rice based cropping systemcould depends upon the selection of variety and appropriate agronomic management practices such as fertilizer management (hossain et al., 2014). aziz et 110 barman et al. al. (2013) reported that multiple cropping system effects soil carbon and nitrogen status, and also improve soil functional properties. nevertheless, continuous cropping causes nutrient mining from soil while a blanket fertilizer dose for all regions without considering the soil nutrient status leads to tremendous damage to soil, environment and economy. sultana et al. (2015) opined that actual recommended fertilizer dose is higher than actual need of fertilizer and this gap creates soil nutrient imbalance.as soil fertility is a major determinant for the success and failure of a crop production system, time demands a suitable fertilizer recommendation based on soil testing for promising four crops based cropping pattern which is agronomically feasible and economically profitable. as such, the present study was undertaken to find out the most suitable fertilizer dose for mustard-boro-t.aus-t.aman cropping pattern at aez-11 considering both the yield and economic return of the system. materials and methods initial soil status the field experiment was executed at the central farm of rars, jashore (aez 11) during 201718 and 2018-19. the initial soil samples from 0-15 cm depth was collected and analyzed before establishing the experiment. initial soil status of experimental field is presented in table 1. table 1. chemical properties of experimentalsoil (initial) at the rars, jashore ph om (%) ca mg k total n % p s b cu fe mn zn meq/100 g soil g g-1 7.7 0.92 12 3.4 0.19 0.048 15.1 18.0 0.14 2.1 38 5.0 2.0 critical level 2.0 0.5 0.12 very low 7.0 10 0.2 0.2 4.0 1.0 0.6 experimental details the experiment was conducted in a randomized complete block design with three replications. eight different treatments viz. t1: 100% npksznb (stb), t2: t1 + 25% n, t3: t1 + 25% np, t4: t1+ 25% nk, t5:t1+ 25% pk, t6:t1+ 25% npk, t7: 75% of t1, t8: native fertility was applied in different plots having size of 4.2m x 3m each. the stb fertilizer dose for mustard, boro, t.aus and t.aman is n138p22k25s0zn1.85, n186p30k23s30zn0, n90p15k2.17s23zn0 and n159p30k7s24zn0, respectively. mustard crop (var. bari sarisha-14) was used as test crop for the first component of the pattern. mustard seeds were sown in line with 30 cm row to row on november 06, 2017 and november 07, 2018. fertilizer n-p-k-s-zn and b were supplied from urea, tsp, mp, gypsum, zinc sulphate and boric acid respectively. all pksznb and 1/3 of n were applied at the time of final land preparation. the remaining two third of n were applied as top dress at 30 and 60 days after sowing. three irrigation and other intercultural operations were done as and when required. the mustard was harvested on january 28, 2018 and january 27, 2019. after mustard, brri dhan28 was transplanted in the same plots on february 3, 2018 and february 2, 2019 with a row to row spacing of 20 cm and plant to plant spacing of 15 cm. all fertilizers including 1/3rd of n were applied before transplanting. rest of n was applied in two installments at 15 and 45 days after transplanting. for t. aus rice, the variety brri dhan48 was used in the experiment. transplanting was done on may 15, 2018 and may 14, 2019 with a row to row spacing of 20 cm and plant to plant spacing of 15 cm. all fertilizers including 1/3rd of n were applied before transplanting. rest of n was applied in two installments at 15 and 45 days after transplanting. for t. aman rice, the variety brri dhan57 was used in the experiments.transplanting was done on july 29, 2018 and july 28, 2019 with increasing crop productivity of four crop based cropping pattern 111 a row to row spacing of 20 cm and plant to plant spacing of 15 cm. t. aman rice was harvested on november 4, 2018 and november 5, 2019. data collection and analysis data on yield and yield contributing characters were recorded and analyzed using statistix 10 software. the means were separated using least significant difference (lsd) at the 5% level of significance. rice equivalent yield is determined by the following equation rice equivalent yield of a crop= yield of that crop (t ha-1) × unit price of that crop unit price of rice economic analysis gross return from this rice based cropping system was calculated by multiplying the yield of crops with their market price. total variable cost included the fertilizer cost. gross margin was calculated by subtracting the variable cost from the gross return. marginal benefit cost ratio (mbcr) was calculated by dividing the marginal value product by total variable cost. results and discussion mustard data regarding yield and yield contributing characters of mustard as influenced by the fertilizer rate has been presented in table 2 & 3. in both the experimental years (2017-2018 and 20182019), 25% npk+100% stb gave highest plant height, no. of branches plant-1, no. of pods plant-1, no. of grains pod-1, 1000 seed weight (g) and stover yield while no fertilizer gave the lowest value of these parameters. in the two consecutive years, about 46% and 48% more yield was obtained than 100% stb dose while 25% more npk was added to 100% stb dose. the native nutrient treatment produced the lowest mustard seed yield (0.91 and 0.96)t ha-1 in jashore during the year of 2017-18 and 2018-19. alike trend of increased yield in mustard due to added fertilizers in 3 or 4 cropping patterns was also reported by barman et al. (2019) and saha et al. (2016). dobermann et al. (2013) opined that site-specific plant nutrient management (stb in our study) can increase yield as well as nutrient use efficiency of crop rotation. table 2. yield and yield contributing characters of mustard during 2017-2018 treat ment plant height (cm) no. of branches no. of pods plant-1 pod length (cm) no. of grains pod-1 ineffective pods plant-1 1000 seed weight (g) seed yield stover yield (t ha-1) t1 82.03b 5.53de 63.53de 4.00bc 32.53c 9.33bcd 3.40cd 1.10c 2.26b t2 84.67ab 6.73bc 73.53c 4.40ab 35.46abc 11.00abc 3.66bc 1.12c 2.30b t3 87.60a 7.00b 87.46b 4.53ab 36.80ab 9.00cd 3.83b 1.43b 2.43ab t4 85.86ab 6.86bc 86.33b 4.53ab 35.53abc 8.00d 3.70bc 1.23c 2.36b t5 82.80b 5.80cd 67.00cd 4.40ab 34.40bc 11.66ab 3.46bcd 1.21c 2.30b t6 89.33a 8.46a 96.20a 4.93a 38.40a 7.00d 4.26a 1.61a 2.70a t7 75.66c 5.40de 59.00ef 3.93bc 28.53d 12.66a 3.20de 1.01d 2.16b t8 61.86d 4.53e 55.33f 3.60c 25.00e 13.33a 2.96e 0.91d 1.56c cv (%) 2.91 9.13 5.19 9.18 5.94 9.14 6.60 6.93 6.85 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. 112 barman et al. table. 3. yield and yield contributing characters of mustard during the year 2018-2019 treat ment plant height (cm) no. of branches no. of pods plant-1 pod length (cm) no. of grains pod-1 ineffective pods plant-1 1000 seed weight (g) seed yield stover yield (t ha-1) t1 95.28bc 5.98 cd 71.33de 4.65bc 36.75 bc 15.02 ab 3.32 cd 1.16 cde 2.23b t2 97.19 b 6.88 bc 81.31 c 5.04 ab 39.32 ab 13.12 bc 3.53 bc 1.35 bcd 2.30 b t3 98.12 ab 7.74 b 95.25 b 5.32a 39.44 ab 13.08 bc 3.72 b 1.63 ab 2.43 b t4 100.01 ab 6.96b 94.03b 5.35a 39.42ab 13.10 bc 3.61 bc 1.41 bc 2.36 b t5 97.00 b 5.76 de 75.02cd 5.28 a 38.43ab 11.87 cd 3.35 bcd 1.36 bcd 2.30 b t6 101.62 a 8.86 a 104.04 a 5.74 a 40.72 a 10.02 d 4.15 a 1.72 a 2.70 a t7 95.13 b 5.62 de 67.22ef 4.02 c 32.76 c 16.62 a 3.11de 1.07de 2.16 b t8 90.12 c 4.87e 62.04f 4.01 c 30.31c 17.32 a 2.86 e 0.96 e 1.60 c cv (%) 2.97 9.42 6.88 6.98 8.23 7.32 6.98 9.11 7.96 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. boro the second component of the cropping pattern was boro rice. the yield contributing characters and grain yield of boro rice are presented in table 4 and table 5. most of the yield contributing characters, straw and grain yield of boro rice was significantly influenced by the different fertilizer treatments. highest plant height was recorded from t6 treatment which was statistically at par with t2, t3, t4 and t5. in both the experimental years, 25% npk with 100% stb gave highest no. of tiller hill-1, no of panicle hill-1, panicle length, grain and straw yield which was statistically similar with all other treatments except control plot or treatment. but numerically t6 treatment produced highest grain yield (6.28 and 6.34 t ha-1) in both the consecutive years. fertilizer has no significant effect on 1000-grain weight. barman et al. (2019) also reported highest boro rice yield from 25% extra npk over 100% stb dose in four crop based cropping pattern. table 4. yield and yield contributing characters of boro rice during the year 2018 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000 grain wt. (g) straw yield grain yield (t ha-1) t1 88.39c 18.89a 18.27a 17.66a 21.30 6.10a 5.45ab t2 90.07ab 19.19a 18.05a 18.14a 21.42 6.37a 5.61ab t3 91.12ab 20.17a 18.18a 18.65a 22.08 6.44a 5.72 a t4 95.01a 19.59a 18.25a 18.76a 22.50 6.70a 5.82ab t5 95.42a 19.95a 18.35a 19.02a 22.89 6.89a 5.73ab t6 93.66a 20.85a 19.68a 19.81a 23.18 6.97a 6.28 a t7 89.92bc 20.08a 17.25a 18.31a 21.42 5.27a 5.35ab t8 79.98d 15.15b 14.48b 16.45b 20.43 4.67b 4.79 b cv (%) 3.56 2.87 2.67 1.91 4.54 10.02 9.53 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. increasing crop productivity of four crop based cropping pattern 113 table 5. yield and yield contributing characters of boro rice during the year 2019 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000grain wt. (g) straw yield grain yield (t ha-1) t1 85.33c 19.74a 19.22a 19.44a 22.36 6.13a 5.43ab t2 89.05ab 19.66a 19.02a 19.42a 23.22 6.12a 5.52ab t3 90.67ab 20.04a 19.06a 19.74a 22.04 6.18a 5.81a t4 93.65a 19.73a 19.11a 19.76a 21.36 6.34a 5.76ab t5 94.47a 20.15a 19.18a 19.48a 21.74 6.11a 5.68ab t6 93.82a 20.22a 19.48a 19.68a 23.18 6.13a 6.34 a t7 86.74bc 20.08a 19.13a 19.22a 21.14 5.67a 5.14ab t8 76.82d 15.01b 14.44b 16.32b 20.73 4.32b 4.28b cv (%) 3.36 2.64 2.45 2.67 5.12 9.86 8.68 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. t. aus rice data on yield and yield contributing characters of t. aus rice was depicted in table 6 & 7. both in 2018 and 2019, the tallest plant was recorded for t6 treatment but it was statistically similar with t2, t3, t4 and t5 treatment. no of tillers hill-1, no of panicle hill-1, panicle length and straw yield was statistically similar for t1, t2, t3, t4 and t5 treatments but for t8 treatment. 1000grain weight was not affected by fertilizer dose. during the experimental years of 2018 and 2019, adding 25% npk over 100% stb provided 44% and 50% higher yield, respectively than 75% of stb dose which was about 68% and 77% higher, respectively compared to native fertility. barman et al. (2020) also reported 64% higher yield from 25% npk+100% stb dose than no fertilizer. an increase of n, p and k fertilizer doses from stb recommended doses significantly increased yield and yield contributing parameters of rice (hasan et al., 2017). table 6. yield and yield contributing characters of t. aus rice during the year 2018 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000 grain wt. (g) straw yield grain yield (t ha-1) t1 82.13c 16.62a 16.18a 16.44a 19.42 4.32a 2.73ab t2 91.45ab 16.64a 16.00a 16.51a 19.54 4.08a 2.76ab t3 91.22ab 16.98a 16.08a 16.64a 19.62 4.04a 2.70ab t4 94.32a 16.64a 16.17a 16.72a 19.71 4.48a 2.74ab t5 95.42a 17.12a 16.28a 16.81a 19.81 4.05a 2.80ab t6 93.87a 17.21a 16.54a 16.92a 19.92 4.01a 3.03 a t7 87.19bc 17.00a 16.18a 16.31a 19.38 3.74a 2.01b t8 77.41d 15.02b 14.33b 14.22b 19.21 2.34b 1.20 c cv (%) 3.87 2.89 3.55 1.86 4.57 10.23 8.11 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. 114 barman et al. table 7. yield and yield contributing characters of t. aus rice during the year 2019 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000 grain wt. (g) straw yield grain yield (t ha-1) t1 82.00c 15.44a 15.14a 15.62a 19.42 4.32a 2.71ab t2 90.12ab 15.55a 15.12a 15.65a 19.35 4.13a 2.73ab t3 90.08ab 16.11a 15.07a 15.96a 19.26 4.06a 2.75ab t4 93.22a 15.77a 15.14a 15.97a 19.47 4.47a 2.77ab t5 94.31a 16.22a 15.18a 15.68a 19.58 4.08a 2.88ab t6 92.71a 16.11a 15.33a 15.89a 19.39 4.09a 3.19 a t7 86.12bc 15.98a 15.02a 15.33a 19.31 3.71a 2.21b t8 76.31d 14.11b 13.21b 13.66b 19.31 2.40b 1.10 c cv (%) 4.12 5.03 3.18 2.34 4.55 8.98 9.20 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. t. aman the forth component of the cropping pattern was t. aman rice. table 8 and table 9 represented the experimental data related to yield and yield contributing characters of t. aman rice. t6 treatment produced the tallest plant which was statistically similar with all other treatment except t7 and t8. control treatment produced the lowest no. of tillers hill-1 while other treatments showed no significant variations in both the consecutive years. there was no significant impact of treatments on panicle length and 1000-grain weight. highest straw yield was recorded from t6 and lowest from t8. during the two consecutive experimental seasons of 2018 and 2019, about 93% and 88% higher yield, respectively was recorded from t6 treatment than control but it was statistically similar with 100% stb dose and other treatments. ali et al. (2009) observed maximum grain yield from soil test value for hyg while saha et al. (2016) reported higher yield from 20% more from the stb dose in potato-maize-t. aman cropping pattern of aez-3. table 8. yield and yield contributing characters of t. aman rice during the year 2018 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000 grain wt. (g) straw yield grain yield (t ha-1) t1 96.42ab 15.44a 15.43b 18.41 21.41 5.43ab 3.32a t2 96.51ab 17.53a 16.52ab 18.55 21.53 5.53abc 3.45a t3 97.64ab 17.61a 16.61ab 18.66 21.62 5.61abc 3.55a t4 97.72ab 16.72a 16.72ab 18.73 21.73 4.71bc 3.65a t5 98.82a 17.81a 16.81ab 18.84 21.83 5.81ab 3.75a t6 98.94a 17.91a 16.91a 18.95 21.93 5.91a 4.08a t7 94.32b 16.33a 15.33ab 18.32 21.31 4.31bc 3.23a t8 72.21c 9.23b 9.23c 18.20 21.21 3.23c 2.11b cv (%) 2.88 4.77 4.75 5.12 4.11 10.82 7.32 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. increasing crop productivity of four crop based cropping pattern 115 table 9. yield and yield contributing characters of t. aman rice during 2019 treatments plant height (cm) no. of tiller hill-1 no. of panicle hill-1 panicle length (cm) 1000 grain wt. (g) straw yield grain yield (t ha-1) t1 95.54ab 15.84a 15.13b 18.44 21.04 5.14ab 3.53a t2 95.55ab 16.85a 16.24ab 18.05 21.55 5.05abc 3.54a t3 96.56ab 16.74a 16.46ab 18.96 21.26 5.06abc 3.65a t4 96.47ab 15.97a 15.58ab 18.67 21.17 4.87bc 3.46a t5 97.58a 16.02a 15.87ab 18.38 21.58 5.78ab 3.57a t6 97.59a 16.11a 16.09a 18.19 21.59 5.89a 3. 98a t7 93.63b 15.74a 15.12ab 18.72 21.33 4.52bc 3.22a t8 71.42c 9.63b 9.02c 18.51 21.22 3.81c 2.08b cv (%) 3.11 4.98 5.21 5.55 4.11 9.22 8.98 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. rice equivalent yield productivity of different crops on the rice based cropping system was determined by rice equivalent yield (rey) which was calculated from yield of component crops. average yield of component crops and rice equivalent yield of mustard was depicted in table 10. from the results of two years research on four crop based cropping pattern, it was observed that the highest rey (3.34 t ha-1) was recorded from t6 (25% extra npk over 100% stb dose) and lowest from t8. rey of mustard was 46% higher than 100% stb dose when 25% more npk was added to it. barman et al. (2020) also documented higher rice equivalent yield of mustard from 25% npk+ 100% stb dose. mondal et al. (2015) also claimed of having 49 to 67% higher productivity from the intensified land use system under four cropped based cropping pattern. inclusion of mustard in rice based cropping pattern increase rey about 45.3-51.6% (hossain et al., 2014). naher et al. (2016) and hossain et al. (2014) opined that short duration varieties and improved four crop based cropping pattern increases total productivity and profitability over farmers existing pattern. table 10. rice equivalent yield of mustard-boro-t. aus-t. aman treatments average yield of crops in the pattern rice equivalent yield mustard in the pattern mustard boro t.aus t.aman t1 1.13 5.44 2.72 3.43 2.26 t2 1.24 5.57 2.75 3.50 2.48 t3 1.53 5.77 2.73 3.60 3.06 t4 1.32 5.79 2.76 3.56 2.64 t5 1.29 5.71 2.84 3.66 2.58 t6 1.67 6.32 3.11 4.03 3.34 t7 1.04 5.25 2.11 3.23 2.08 t8 0.94 4.53 1.15 2.10 1.88 price : 1 kg mustard = tk. 50, 1 kg rice = tk. 25 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. 116 barman et al. economic analysis cost and return analysis was done on the basis of prevailing market price of the commodities. economics analysis of the cropping pattern mustard-boro-t.aus-t.aman was delineated in table 11. it was observed that highest gross return, total variable cost, gross margin and marginal value product was obtained from 25% extra npk over 100% stb dose. the maximum marginal benefit cost ratio was also gained from t6 treatment. although the total variable cost is higher for t6 but its output value surpassed other fertilizer packages. that’s why 25% more npk with 100% stb dose was the most economically profitable fertilizer package for mustard-borot.aus -t.aman cropping pattern under aez-11. hossain et al. (2014) found highest mbcr from mustard-boro-t.aus-t.aman. thus four crop based cropping pattern would play a vital role to ensure food security of the country in upcoming days (mondal et al., 2014) and also improve socio-economic condition of farmers. table 11.economic analysis of the cropping pattern mustardboro-t. aus-t. aman treatments gross return of the system total variable cost gross margin marginal product value (mvp) marginal benefit cost ratio (mbcr) (tk./ha) t1 346250 40708 305542 104750 2.57 t2 357500 42231 315269 116000 2.75 t3 379000 43252 335748 137500 3.18 t4 368750 42682 326068 127250 2.98 t5 369750 42180 327570 128250 3.04 t6 420000 43703 376297 178500 4.08 t7 316750 30531 286219 75250 2.46 t8 241500 0 241500 urea= 16 tk kg-1, tsp= 25 tk kg-1, mop= 15 tk kg-1, gypsum= 12 tk kg-1, zinc sulphate= 200 tk kg-1 t1: 100% stb, t2: t1 + 25% n, t3: t1 + 25% np, t4: t1 + 25% nk, t5: t1 + 25% pk, t6: t1 + 25% npk, t7: 75% of t1, t8: control treatment or native fertility. conclusion considering the system productivity, and cost and return analysis of the experiment, it may be concluded that 25% extra npk with 100% stb dose is agronomically feasible and economically profitable for mustard-boro-t.aus-t.aman cropping pattern in aez-11. so, this fertilizer dose may be followed for a remunerative and productive rice based mustard-boro-t. aus-t. aman cropping system under jashore region. further experimentation will be required under different aezs’ to find out suitable region specific fertilizer packages for this pattern. references ali, m.r., d.j. costa, m.a. sayed, m.a.h. khanand j.a. abedin. 2009. development of fertilizer recommendation for the cropping pattern potato-boro-t. aman in irrigated medium highland condition under aez -9. bangladesh j. agril. res. 34(1): 41-49. aziz i, t. mahmood, k.r. islam and e. ashraf. 2013. estimation of cropping system impacts on c and n status of soil. int. j. agric. appl. sci. 5(1): 1-7. barman, a., m.m. masud, s. akhter, m.a. hossain and s. shome. 2020. development of fertilizer recommendation of four crops grown under the cropping pattern: mustard-borot. aust. aman in aez–8. bangladesh j. agril. res. 45(2): 113-123. increasing crop productivity of four crop based cropping pattern 117 barman, a., s. shome, m. j. alam, s. akhter and m.a. hossain. 2019. fertilizer recommendation for four crop based cropping pattern: potatoborot. aus-t. aman under aez–11. bangladesh agron. j. 22(1): 71-78. bbs. 2019. statistical yearbook of bangladesh. 39th edition. statistics division, ministry of planning, govt. of the people’s republic of bangladesh. p.47. dobermann, a., r. nelson, d. beever, d. bergvinson, e. crowley, g. denning, k. giller, j. d’arros hughes, m. jahn, j. lynam, w. masters, r. naylor, g. neath, i. onyido, t. remington, i. wrightand and f. zhang. 2013. solutions for sustainable agriculture and food systems. technical report for the post-2015 development agenda. sustainable development solutions network, new york. hasan, a.b.m.m., s.m. shamsuzzaman, h.a.k. chowdhury, s.m. rasel, n.h. khan, m.e. rahman, m. mehnaz and a.w. samsuri. 2017. effect of different fertilizer packages on the yield and yield attributes on brri dhan47 in saline areas. bangladesh j. bot. 46(1): 467-472. hossain, i., m.r.i. mondal, m.j. islam, m.a. aziz, a.s.m.m.r. khan and f. begum. 2014. four crop based cropping pattern studies for increasing cropping intensity and productivity in rajshahi region of bangladesh. bangladesh agron. j. 17(2): 55-60. islam, m.a., m.j. islam, m.a. ali, a.s.m.m.r. khan, m.f. hossain and m. moniruzzaman. 2018. transforming triple cropping system to four crops pattern: an approach of enhancing system productivity through intensifying land use system in bangladesh. int. j. agon. doi: pageshttps://doi.org/10.1155/2018/7149835. mondal, r.i., f. begum, a. aziz and s.h. sharif. 2015. crop sequences for increasing cropping intensity and productivity. saarc j. agril. 13(1): 135147. naher q., m.r. amin., m.r. islam m.a. ali, a.k. choudhury, m.k. hasan and a.s.m.m.r. khan. 2016. location specific climate resilient agricultural technologies in bangladesh. ofrd (onfarm research division), bari, bangladesh. pp.37-38. parvin, n., a. khatun, m.k. quais and m. nasim. 2017. cropping pattern, intensity and diversity in dhaka region. bangladesh rice j. 21(2): 123-141. saha, p.k., f. rahman, m. akter, r. islam, a.t.m.s. hossain and m.g. ali. 2016. integrated nutrient management for potato-maize-t. aman rice cropping pattern in bangladesh. rice j. 20(1): 51-58. sultana, j., m.n.a. siddique and m.r. abdullah. 2015. fertilizer recommendation for agriculture: practice, practicalities and adaptation in bangladesh and netherlands. int. j. bus. manag. soc. res. 1(1): 21-40. file:///c:\users\dell\downloads\39th microsoft word baj 347c__press bangladesh agron. j. 2020, 23(1): 1-11 improving performances of late transplant aman rice through spacing and nutrient management options r.m. foysal1, b. karmakar2, m.a.r. sarkar1, a.k.m.h. akther3, s. akter4 and b. ahmed2 1department of agronomy, bangladesh agricultural university, mymensingh, bangladesh 3deputy inspector general (dig), bangladesh police.4khulna university, khulna 2adaptive research division, bangladesh rice research institute, gazipur, bangladesh. corresponding e-mail: biswajitbrri@gmail.com (received: 03 march, 2020, accepted: 21 june, 2020) keywords: poultry manure, vermicompost, panicle, grain yield, harvest index, brri dhan46. abstract crop and nutrient management options could improve the yield performances of late transplant aman rice which is generally lower compared to optimum transplanting. to address these issues, an experiment was conducted at bangladesh agricultural university, mymensingh to investigate the effect of spacing and nutrient management options on yield and yield components of late transplant aman rice and to find out the better treatment combination to obtain higher yield. the experiment was laid out in two factors randomized complete block design (rcbd) with three replications consisting of three spacings viz. s1 =25 cm×15 cm , s2 =25 cm×10 cm and s3 =20 cm×10 cm; and eight nutrient management options viz. n0 = control (no fertilizer), n1 = poultry manure @ 5 t ha-1 , n2 = vermicompost @ 3 t ha-1 , n3 = researcher’s practice (urea, tsp, mop, gypsum and znso4 @ 180,75,105, 60 and 7.5 kg ha-1, respectively), n4 = 75% n3 + poultry manure @ 2.5 t ha-1, n5 = 50% n3+ poultry manure @ 5 t ha-1, n6 = 75% n3+ vermicompost @ 1.5 t ha-1 and n7 = 50% n3+ vermicompost @ 3 t ha-1. pre-germinated seeds of brri dhan46 were sown in wet nursery bed on 16 august and 30–d–old seedlings were transplanted as per treatments on 15 september in 2017. yield and yield components were significantly influenced by spacing, nutrient management options and their interactions. the highest yield (5.20 t ha-1) was obtained the spacing 25 cm×10 cm which was at par with 25 cm×15 cm (5.12 t ha-1) and the lowest (4.88 t ha-1) was in 20 cm×10 cm. statistically similar grain yield 5.85, 5.81 and 5.79 t ha-1 were produced in the treatments n3, n4 and n6, respectively. grain yield increased in the treatments having combination of inorganic and organic nutrient, and also in the optimum inorganic fertilizers (researcher’s practice). the highest grain yield (5.98 t ha-1) was obtained in the interaction s2×n3 which was at par with s1 x n3, s1 x n4, s1 x n6, s2 x n4 and s2 x n6. performances of sole organic fertilizers were not satisfactory level. therefore, reduced amount (75%) of inorganic fertilizers combined with organic fertilizers (poultry manure 2.5 t ha-1 or vermicompost 1.5 t ha-1) along with closer spacing 25 cm×10 cm would be recommended to achieve better and sustainable yield performance of late transplant aman rice cv. brri dhan46. introduction rice is the staple and primary food source for more than one-third of world's population (karmakar et al., 2004; singh and singh, 2008; sharada and sujathamma, 2018). almost one fourth of the calories consumed by the entire world population come from rice (subudhi et al., 2 foysal et al. 2006). as the primary food crop of bangladesh, the area and production of rice were 11.61 million hectares and 36.28 million tons, respectively (bbs, 2019). among the rice seasons, aman rice covers 5.68 m ha (48.91% of total rice area) and produced 13.99 m t (38.57% of total cleaned rice production) (bbs, 2019). aman rice cultivation is cost-effective utilizing rain water as the crop grown in wet season. however, sometimes the aman crop damaged due flood and flash flood and some low lying areas are regularly affected by flood and flash flood. in those cases, late transplant aman rice could play vital role to have good harvest. however, decreasing rate of agricultural land by 0.4% per annum (hasan et al., 2013; karmakar and ali, 2019) and increasing population by 1.28% (bbs, 2019) are the major limitation of horizontal expansion of rice cropping area. the rapid population growth always keeps farm and farmers as well as legislators under pressure for producing more and more rice. moreover, in recent years frequent flash flood drastically declines the production of rice to some great extant. the loss of rice harvest costs huge sum of foreign currency due to import of rice to meet our national demand. flood hits during the monsoon season or on the onset of monsoon season, may to july. sometimes this flood costs the young transplanted seedlings death in some low land areas. after decreasing the water level late transplanted aman rice could be cultivated. brri dhan46 is late transplant aman rice released by bangladesh rice research institute in the year of 2007. the yield of late transplant aman rice can be increased with the modern cultivation practices like proper spacing arrangement, nutrient management, seedling age etc. a crop production system with high yield targets cannot be sustainable unless balanced nutrient inputs are supplied to soil against nutrient removal by crops (bhuiyan et al., 2007). imbalanced and continuous application of chemical fertilizers on crop production might be disturbed soil health and microbes (khadka et al., 2008). application of inorganic fertilizer is considered to be most effective measures for improving rice production. mythili et al. (2003) reported that zinc and sulphur deficient soil with n, p, k, s as gypsum coupled with poultry manure produced the highest grain yield (5.63 t ha-1). it revealed that the efficient fertilizer management gives higher yield of crop and reduces fertilizer cost (hasan et al., 2004). organic sources of nutrients applied to preceding crop can benefit the succeeding crop. therefore, a judicious integration of chemical fertilizer along with organic manure may help to maintained soil fertility as well as increase crop productivity. poultry manure contains sufficient amount of nutrients especially it has enough phosphorus that very beneficial for rice crop. fresh chicken manure is rich with 0.8% potassium, 0.4 % to 0.7 % phosphorus, and 0.9 % to 1.5 % nitrogen (wikipedia, 2019a). vermicompost is the product of the decomposition process using various species of worms, usually red wigglers, white worms, and other earthworms, to create a mixture of decomposing vegetable or food waste, bedding materials, and vermicompost. vermicompost is the end-product of the breakdown of organic matter by earthworms. it improves soil aeration, enriches soil with microorganisms (adding plant hormones such as auxins and gibberellic acid) (wikipedia, 2019a). average organic matter content of the soil of bangladesh is less than 1.5% and in many cases it is less than 1% (barc, 2018). islam et al. (2015) reported that application of 50% recommended chemical fertilizers + poultry manure @ 2.5 t ha-1 produced the highest plant height, number of tillers hill-1. thus, any alternative means has to be suggested to the farmers to maintain the high level of productivity. that’s why, integrated use of organic manures such as vermicompost, poultry manure and inorganic fertilizers can be an effective strategy for nutrient management in rice as well as to sustain long term productivity. so, the proper utilization of different source of nutrients in context of crop-soil productivity must be explored for the existence of the people. in some regions the soil are not only deficient in macronutrients such as n, p, k and s but also some of the micronutrients such as zn and b. sreelatha et al. (2006) found the grain yield of rice applying poultry manure @ 1 t ha-1 along with recommended dose of fertilizer. it may supply sufficient amount of s, zn and b for growth of rice plants. application improving yield performances of late transplant aman rice 3 of poultry manure may play an important role in rice cultivation when used alone or in combination with chemical fertilizers. vermicompost is rich in nitrogen (2-3%), phosphorus (1.55-2.25%) and potash (1.85-2.25%); and other micronutrients (wikipedia, 2019b). it is beneficial for soil microbes and also contains ‘plant growth hormones & enzymes’. vermicompost retains nutrients for long time and while the conventional compost fails to deliver the required amount of macro and micronutrients including the vital nkp to plants in shorter time. combination of 75% of recommended inorganic fertilizers and cow-dung (5 t ha-1) improves the physical, chemical and biological properties of soil and thus it helps to increase and conserves the soil productivity (marziaet al., 2016). sustainable production of crops cannot be maintained by using only chemical fertilizers and similarly it is not possible to obtain higher crop yield by using organic manure alone (moe et al., 2019). to expand crop productivity more emphasis should be given on spacing along with integrated nutrient management. therefore, the experiment was executed to investigate the effect of spacing and nutrient management options on yield and yield components of late transplant aman rice (brri dhan46) and to find out the better combination of spacing and nutrient management options to obtain higher yield. materials and methods an experiment was conducted at agronomy field laboratory, bangladesh agricultural university, mymensingh during july to december 2017. the experimental field was located at 24.75o n latitude and 90.50o e longitude at an average altitude of 18 m from above the sea level. the site belongs to the old brahmaputra floodplain agro-ecological zone (aez) 9 having non-calcareous dark-grey floodplain and silty loam soil. the soil of the experimental field was more or less neutral in nature (ph 6.82) and low in organic matter content (1.19%). the climate of the locality was tropical in nature characterized by high temperature, high humidity and heavy precipitation with occasional breezy winds in aman season (wet season) (june-october) and scanty rainfall associated with moderate to low average air temperature (oc), relative humidity (%), rainfall (mm) and sunshine (day-1) during the experimental period. the experiment was comprised two factors covering three spacings s1 = 25 cm×15 cm, s2 = 25 cm×10 cm and s3 =20 cm×10 cm; and eight nutrient management options viz. n0 = control (no fertilizer), n1 = poultry manure @ 5 t ha-1 , n2 = vermicompost @ 3 t ha-1 , n3 = researcher’s practice (urea, tsp, mop, gypsum and znso4 @ 180,75,105, 60 and 7.5 kg ha-1, respectively), n4 = 75% n3 + poultry manure @ 2.5 t ha-1 , n5 = 50% n3 + poultry manure @ 5 t ha-1 , n6 = 75% n3 + vermicompost @ 1.5 t ha-1 and n7 = 50% n3 + vermicompost @ 3 t ha-1.the experiment was laid out in a randomized complete block design with three replications. the size of unit plot was 4 m × 5 m. high yielding late transplant aman rice variety brri dhan46 released bybangladesh rice research institute (brri) was used in the experiment. seeds of brri dhan46 were collected from brri, gazipur. pre-germinated seeds were sown in the wet nursery bed on 16 august and 30–d–old seedlings were transplanted as per the treatments on 15 september in 2017. seeding and transplanting was purposively delayed to address the late planting effect and to find out how can overcome that adverse effect utilizing that late transplant aman rice variety brri dahn46. for the treatment n1, n4 and n5; poultry manure @ 5, 2.5 and 5 t ha-1; and for the treatment n2, n6 and n7; vermicompost@ 3, 1.5 and 3 t ha-1, respectively were applied at 10 days before transplanting. all inorganic fertilizers except urea having in different treatments were applied one day before transplanting during final land preparation. nitrogen was top dressed as per treatment in the form of urea (prilled) in three equal splits; one-third during final land preparation as basal dose, one-third at 15 days after transplanting (dat) and the rest one-third at 30 dat. the distance maintained between two unit plots was 0.5 m and between blocks was 1 m. the bunds around individual plots were made firm enough placing polythene sheet inside the soil up 4 foysal et al. to 50 cm to control water and nutrient movement among the plots. yield and yield parameters like panicles hill-1, grains panicle-1, panicle length, spikelet sterility, 1000-grain weight, grain, straw and biological yield; harvest index were recorded at harvest. data collected on different parameters were analyzed using the statistical software mstat-c program and mean differences among the treatment were adjusted by using the least significance test (lsd) at 5% level of significance (gomez and gomez, 1984). results and discussion the results of the experiment on effect of spacing and integrated nutrient management and their interaction on the growth and yield of aman rice cv. brri dhan46 have been presented and discussed in this chapter. grain yield spacing had significant effect on grain yield at 1% level of probability. these results were in confirmation of the findings of karmakar et al. (2014) and obulamma and reddeppa (2002). the results indicated that the spacing 25 cm x 10 cm (s2) produced the highest grain yield (5.20 t ha-1) that was statistically similar with 25 cm x 15 cm (5.12 t ha-1) (table 1). the lowest grain yield (4.88 t ha-1) was recorded from s3 (20 cm×10 cm). the highest grain yield from s2(25 cm×10 cm) was due to the highest number of effective tillers hill-1.the crop got less time for tillering so that the medium spacing produced the highest yield. grain yield differences might be due to the availability of sunlight for photosynthesis inserted across the row spacing 25 cm. table1. effect of spacing on yield components and yield of brri dhan46 spacing panicles hill-1 (no.) panicle length (cm) grains panicle-1 (no.) sterile spikelet panicle-1 (no.) 1000 grain wt. (g) grain yield (t ha-1) harvest index (%) s1 8.86a 23.14 129.21 12.57 26.14 5.12ab 45.23b s2 9.14a 23.10 129.73 12.43 26.30 5.20a 47.88a s3 7.65b 22.87 127.44 13.01 26.09 4.88b 45.28b lsd(0.05) 0.73 0.52 5.12 0.69 0.38 0.14 0.26 f-test ** ns ns ns ns ** ** ** =significant at 1% level of probability and, ns = not significant. s1 = 25 cm×15 cm, s2 =25 cm×10 cm, and s3 = 20 cm×10 cm grain yield significantly affected by the nutrient management options at 1% level of probability. these results are in good harmony with karmakar et al. (2002).the results showed that the treatment n3 (researcher’s practice) produced the highest grain yield (5.85 t ha -1), however it was at par and very close to n4 (75% n3 + poultry manure 2.5 t ha-1) and n6 (75% n3 + vermicompost 1.5 t ha-1) those yielded 5.81 and 5.75 t ha-1, respectively (fig. 1). the lowest (3.12 t ha-1) grain yield was found in treatment n0 (no fertilizer). yield of the treatments applied sole poultry manure and sole vermicompost were significantly higher than the control plot, nevertheless, those were significantly lower than the treatments where applied the combination of organic and inorganic fertilizers. moreover, long term effect of organic fertilizers is very much promising as nutrients release from it slowly. however, poultry manure and vermicompost with 75% inorganic fertilizers produced similar yield with researcher’s practice. it is very much helpful to get higher yield and to improve soil health. the crop was transplanted at least one month improving yield performances of late transplant aman rice 5 later than the optimum planting date (15 july to 15 august) (brri, 2019) so that the crop got less time in the monsoon to utilize the nutrient from the organic fertilizers. in this aspect, n3 (researcher’s practice: 110% inorganic fertilizers), n4 (75% n3+ poultry manure 2.5 t ha-1) and n6 (75% n3+ vermicompost 1.5 t ha-1) released nutrient sufficiently and readily which may be a strong reason for the higher yield of these treatments. yield and yield component increased with increased nutrient levels (salem et al., 2011). sarkar et al. (2014) also indicated the highest number of effective tillers hill-1, grains panicle-1, panicle length and grain yield were recorded in the treatment using 75% recommended dose of fertilizer. mollah et al. (2011) found that cow dung had a positive effect on grain and straw yields of aman rice. interaction of spacings and nutrient management options showed significant variation in respect of grain yield. the highest grain yield (5.98 t ha-1) was produced by the combination of s2×n3 that at par with s1×n3, s2 x n4, s1 x n4 and s2 x n6 (table 3). the lowest grain yield (4.05 t ha1) was produced by s1 (25 cm×15 cm) with control (no manures and fertilizer). in general higher grain yield was observed in the interactions of the spacing 25 cm x 10 or 15 cm and researcher’s practice along with reduced amount (75%) of researcher’s practice. the results showed that combination of inorganic and organic fertilizers along with bit closer spacing 25 cm x 10 cm might be better to get better yield from late transplant aman rice. these results are corroborated with sarker et al. (2015) in brri dhan33 and islam et al. (2007) who observed that conventional spacing of 25 cm×15 cm in combination with 50% n, p, k, s, zn and 5 t ha-1 poultry manure appeared as the best practice for transplant aman rice. fig.1. effect of nutrient management options on grain yield of late transplant aman rice (brri dhan46). n0 = control, n1 = poultry manure @ 5 t ha-1, n2 = vermicompost @ 3 t ha-1, n3 = recommended dose of inorganic fertilizer, n4 = 75% n3 + poultry manure @ 2.5 t ha-1, n5 = 50% n3+ poultry manure @ 5 t ha-1, n6 = 75% n3+ vermicompost @ 1.5 t ha-1, n7 = 50% n3 + vermicompost @ 3 t ha-1 2.72 3.95 4.16 5.85 5.81 5.34 5.79 5.53 0 1 2 3 4 5 6 7 n0 n1 n2 n3 n4 n5 n6 n7 g ra in y ie ld ( t h a1 ) nutrient management options lsd0.05 = 0.17 6 foysal et al. panicle production spacing had significant effect on number of panicles hill-1. these results are in good alignment with the findings of karmakar et al. (2014); verma et al. (2002); patra and nayak (2001).the number of panicles hill-1ranged from 7.65 to 9.14 among the spacings. the results indicated that s1 (25cm×10cm)produced the highest number of panicles hill-1(9.14) followed by 25 cm x 15 cm (8.86) (table 1). in comparison with these results, mobasser et al. (2007) reported that the spacing had a significant effect on the total number of tillers hill-1. the probable reasons of difference in producing the number of panicles hill-1 was mainly the spacing. the lowest number (7.65) was recorded in s3 (20cm×10cm) which is statistically identical to s3 (20cm×10cm). wang et al. (2006) found that greater light interception by middle and lower layer leaves, equal row spacings were appropriate for cultivars with erect and semi erect panicles. nutrient management exerted significant effect on the number of panicles at 5% level of probability. sarker et al. (2015) reported that number of effective and tillers hill-1 influenced by organic and inorganic fertilizers. it was found that n3 (recommended dose of inorganic fertilizer) produced the highest number of panicles hill-1(8.92) followed by n4 (8.88) (table 2). probably this treatment provided adequate nutrients to the plants and as a result produced the highest number of panicles hill-1. where n2 (vermicompost @ 3 t ha-1), n4 (75% researcher’s practice+ poultry manure @ 2.5 t ha-1), n6 (75% researcher’s practice+ vermicompost @ 1.5 t ha-1) and n7 (50% researcher’s practice+ vermicompost @ 3 t ha-1) were statistically identical with n3. the lowest number of panicles hill-1(7.50) was obtained in n0 (control). number of effective tillers hill-1 was not significant due to the interaction of spacing and nutrient management options. number of panicles hill-1 ranged from 7.00 to 9.88 (table 3). panicle length spacing, nutrient management options and their interactions had no significant influence on panicle length. in contrast, tyeb et al. (2013) and karmakar et al. (2002) observed that spacing has significant effect on panicle length. tyeb et al. (2013) reported that the highest panicle length was obtained from 25 cm×20 cm spacing while the lowest panicle length was obtained from 20 cm×10 cm, among the spacings of 25 cm×15 cm, 25 cm×20 cm, 20 cm×20 cm and 20 cm×10 cm used for4 varieties of rice viz. brri dhan41, brri dhan46, brri dhan51 and brri dhan52. panicle length was significantly affected by nutrient management options. kandil et al. (2010) and mannan et al. (2010) reported similar results. the longest panicle was produced in n4 (8.96 cm) followed by n3 (8.92 cm) and the shortest was in n0 (7.25 cm). grains panicle-1 spacing had insignificant effect on the number of grains production per panicle. in contrast, pol et al. (2005) reported that rice crop transplanted with 20 cm×20 cm spacing produced significantly more number of panicle hill-1. nutrient management options had significant effect on the number of grains panicle-1 at 5% level of probability (table 2). these findings collaborate with those reported by sarker et al. (2015) reported that grains panicle-1 significantly influenced by organic and inorganic fertilizers. the results indicated that the treatment, n2 (vermicompost @ 3 t ha-1 ), n4 (75% researcher’s practice+ poultry manure @ 2.5 t ha-1), n5 (50% researcher’s practice+ poultry manure @ 5 t ha-1), n6 (75% researcher’s practice+ vermicompost @ 1.5 t ha-1) and n7 (50% researcher’s practice+ vermicompost @ 3 t ha-1) were statistically identical with highest number of grains panicle-1. the lowest number of grains panicle-1 was found inn0 (control) followed by n1 (poultry manure @ 5 t ha-1). interaction of improving yield performances of late transplant aman rice 7 spacing and nutrient management had insignificant variation in terms of grains panicle-1 at 5% level of probability. table 2. effect of integrated nutrient management options on yield components and yield of late transplant aman rice brri dhan46 nutrient management options panicles hill-1 (no.) panicle length (cm) grains panicle-1 (no.) sterile spikelet panicle-1 (no.) 1000 grain wt. (g) harvest index (%) n0 7.25b 20.2 102.88c 12.6 25.7 43.33f n1 7.62b 21.32 120.57b 13.1 26.0 46.60c n2 7.9ab 22.51 126.52ab 12.7 26.1 46.47e n3 8.92a 23.26 131.68a 12.4 26.3 48.10b n4 8.96a 23.05 131.73a 12.2 26.3 48.15de n5 7.61b 23.1 130.58a 12.6 26.1 45.54c n6 8.47ab 23.0 128.02ab 12.1 26.3 46.23cd n7 8.40ab 23.3 129.15ab 12.2 26.2 45.69a lsd(0.05) 1.2 1.8 8.35 1.1 0.73 0.42 f-test * * * ns ns ** ** =significant at 1% and * =significant at 5% level of probability, ns = not significant. n0 = control, n1 = poultry manure @ 5 t ha-1, n2 = vermicompost @ 3 t ha-1, n3 = researcher’s practice, n4 = 75% n3 + poultry manure @ 2.5 t ha-1, n5 = 50% n3+ poultry manure @ 5 t ha-1, n6 = 75% n3+ vermicompost @ 1.5 t ha-1, n7 = 50% n3 + vermicompost @ 3 t ha-1 sterile spikelet panicle-1 number of sterile spikelet panicle-1 was not significantly influenced by spacing and nutrient management options and their interactions (table 3).karmakar et al. (2014) also found that spacing had no significant effect on spikelet sterility. however, the highest sterile spikelets panicle-1 (13.69) was found in the interaction of s3 x n1 while it was the lowest (11.53) in s2 x n4). table 3. interaction effect of spacing and nutrient management options on yield components and yield of late transplant aman rice brri dhan46. interaction s××××n panicles hill-1 (no.) panicle length (cm) grains panicle-1 (no.) sterile spikelet panicle-1 (no.) 1000 grain wt. (g) grain yield (t ha-1) harvest index (%) s1×n0 7.00 22.21 121.6cd 14.0 26.13 4.05l 43.00k s1×n1 7.77 23.27 133.7abc 13.44 26.29 5.07ghi 46.41fg s1×n2 9.08 23.33 137.2a 12.04 26.14 5.00i 43.67k s1×n3 9.81 23.49 140.7a 15.40 26.27 5.95a 48.45a s1×n4 9.67 23.46 138.4a 15.15 26.31 5.88a 47.52ab s1×n5 8.11 22.59 126.9abcd 12.75 26.07 5.47de 46.37fg s1×n6 9.55 23.55 137.7a 13.91 26.24 5.74ab 45.56ij s1×n7 8.78 23.44 133.2abcd 12.15 26.26 5.57cd 47.28de s2×n0 7.11 23.79 120.9d 15.64 26.32 3.71m 43.45k s2×n1 8.10 22.95 127.9abcd 13.06 26.30 4.74j 47.09def 8 foysal et al. interaction s××××n panicles hill-1 (no.) panicle length (cm) grains panicle-1 (no.) sterile spikelet panicle-1 (no.) 1000 grain wt. (g) grain yield (t ha-1) harvest index (%) s2×n2 8.51 22.84 129.4abcd 12.29 26.24 5.16gh 46.12ghi s2×n3 9.22 23.61 139.1a 16.02 26.43 5.98a 48.54a s2×n4 9.00 23.48 136.3a 15.53 26.25 5.86a 47.25ab s2×n5 6.78 23.69 130.6abc 13.02 26.27 5.08ghi 44.98j s2×n6 8.55 23.26 135.9ab 15.26 26.41 5.81a 45.57bc s2×n7 8.33 23.91 138.5a 12.60 26.18 5.13gh 47.30ab s3×n0 7.44 23.07 120.1d 16.19 26.30 4.25k 43.55k s3×n1 7.00 23.64 126.1abc 13.69 26.29 5.05hi 46.29bc s3×n2 6.66 23.21 128.6abc 12.75 26.31 5.34f 46.63efg s3×n3 9.44 23.17 133.2ab 12.95 26.22 5.77ab 47.10abc s3×n4 8.78 23.51 136.5ab 12.98 26.31 5.63c 48.08a s3×n5 7.88 22.97 131.1abcd 13.89 26.35 5.48de 48.26a s3×n6 8.40 23.13 128.4abcd 12.22 26.19 5.11ghi 47.56bcd s3×n7 8.00 22.27 123.8bcd 13.91 26.37 5.00i 48.18a lsd (0.05) 4.06 1.56 14.5 5.96 0.62 0.22 0.72 f-test ns ns * ns ns ** ** ** =significant at 1% and * =significant at 5% level of probability, ns = not significant. s1 = 25 cm × 15 cm, s2 =25 cm×10 cm and s3 = 20 cm × 10 cm n0 = control, n1 = poultry manure @ 5 t ha-1, n2 = vermicompost @ 3 t ha-1 , n3 = researcher’s practice, n4 = 75% n3 + poultry manure @ 2.5 t ha-1 , n5 = 50% n3+ poultry manure @ 5 t ha-1 , n6 = 75% n3+ vermicompost @ 1.5 t ha-1 , n7 = 50% n3 + vermicompost @ 3 t ha-1 1000-grain weight spacing and nutrient management exerted insignificant effect on 1000-grain weight. grain weight is mostly genetic characteristics so that it did not affected by spacing (karmakar et al., 2014), nutrient management options and their interactions. islam et al. (2015) also reported that the interaction effect of date of transplanting and spacing was found significant for yield and plant characters except 1000-grain weight. in contrast, subhendu et al. (2003) found that 1000grain weight significantly affected by nutrient management options. interaction effect between spacing and nutrient management options under the study exerted insignificant effect on 1000grain weight (table 3). harvest index spacing had significant influence on harvest index at 1% level of probability (table 1). these results are in good harmony with karmakar et al. (2014). the spacing s2 (20cm×10cm) gave the highest harvest index (47.88%). nutrient management also showed significant influence on harvest index (mondal and swamy, 2003). the highest harvest index (48.15%) was found in the treatment n4and the lowest (43.33%) was in treatment n0 (no manures and fertilizer (table 2).the effect of interaction of spacing and nutrient management options on harvest index was significant at 1% level of probability (table 3). interaction of s2×n3showed the highest harvest index (48.54%), which was statistically identical with s2 x n4, s1 x n3, s1 x n4, s3×n5 and s3×n4. the lowest harvest index (43.00%) was found in the interaction of s1×n0 (25cm×15cm spacing × no fertilizer and manure). improving yield performances of late transplant aman rice 9 conclusion nutrient management options, spacings and their interaction had significant influence on yield and yield components of late transplant aman rice cv. brri dhan46. statistically similar yield were produced in the spacings25 cm x 10 cm and 25 cm x 15 cm, and the treatment combinations of poultry manure (2.5 t ha-1) and vermicompost (1.5 t ha-1) with 75% of the researcher’s practice (urea, tsp, mop, gypsum and znso4 @ 180,75,105, 60 and 7.5 kg ha-1, respectively). yield performance of the researcher’s practice was also statistically similar with organic and inorganic fertilizers treatments. moreover, yield performances of sole organic fertilizers were not satisfactory level. moreover, long term effect of organic fertilizers is very much promising as nutrients release from it slowly. it could be recommended that combination of reduced amount (75%) of inorganic fertilizers and organic fertilizers (poultry manure 2.5 t ha-1 or vermicompost 1.5 t ha-1) along with 25 cm x 10 cmor 25 cm x 15 cm spacingwould be recommended to accomplish higher yield and sustainable performances of late transplant aman rice cv. brri dhan46. references barc (bangladesh agricultural research council). 2018. fertilizer recommendation guide. barc, farmgate, dhaka, bangladesh. bbs (bangladesh bureau of statistics). 2019. the yearbook of agricultural statistics of bangladesh. statistics div., ministry of planning. govt. peoples repub., bangladesh, dhaka. p.54. brri (bangladesh rice research institute). 2019. adhunik dhaner chash (cultivation of modern rice), 22th edition, gazipur, bangladesh. pp.5-81. bhuiyan, m.s.h., m.s. hossain, m.a. sobahan, m.a. alam and m.s. ali. 2007. effect of organic manures and nitrogen levels on plant height and number of tillers nhill-1 of transplant aman rice. j. subtrop. agric. res. dev. 5(3): 291-296. gomez, k.a. and a.a. gomez. 1984. duncan's multiple range test. statistical procedures for agricultural research. 2nd edn. jhon wiley and sons.pp.207-215. hasan, m.k., m.a.r. sarkar and a.k. hasan. 2004. effect of poultry manure based integrated fertilizer management on growth and yield of aromatic rice. bangladesh j. seed sci. tech. 8(2): 97-103. hasan, m. n., m.s. hossain, m.a. bari and m.r. islam. 2013. agricultural land availability in bangladesh. soil resource development institute, dhaka, bangladesh. pp.1-42. islam, a.k.m.a., m.a.r. sarkar and n. islam. 2007. effect of spacing and nutrient management in sri method on the yield components and yield of transplant aman rice. bangladesh j. crop sci. 18(1): 1-6. islam, s.m.m., s.k. paul and m.a.r. sarkar. 2015. effect of weeding regime and integrated nutrient management on yield contributing characters and yield of brri dhan49. crop weed. 11:193-197. karmakar, b., m.a.r. sarkar, m.r. uddin and m. biswas. 2002. effect of row arrangements, number of seedlings per hill and nitrogen rates on yield and yield components of late transplanting aman rice. bangladesh j. agril. sci. 29(2): 275-281. karmakar, b., m.a. ali, m.a. mazid, j. duxbury and c.a. meizner. 2004. validation of system of rice intensification (sri) practice through spacing, seedling age and water management. bangladesh agron. j. 10(1&2): 13-21. karmakar, b., m.a.r. sarkar, m.a. ali and s.m. haefele. 2014. optimizing plant density of the promising rice genotypes in northwest bangladesh. bangladesh rice j. 18(1&2): 1-8. 10 foysal et al. karmakar, b. and m.a. ali. 2019. production and preservation of quality rice seed. 1st edition, bangladesh rice research institute (brri), gazipur, bangladesh. pp.1-36. kandil, a.a., s.e. el-kalla, a.t. badawi and o.m. el-shayb. 2010. effect of hill spacing, nitrogen levels and harvest date on rice productivity and grain quality. crop environ. 1(1): 22-26. khadka,y.g., s.k. rai and s.raut. 2008. long term effects of organic and inorganic fertilizers on rice under rice-wheat cropping sequence. nepal j. sci. tech. 9: 7-13. mannan, m.a., m.s.u. bhuiya, s.m.a. hossain and m.i.m. akand. 2010. optimization of nitrogen rate for aromatic basmati rice (oryza sativa l.). bangladesh j. agril. res. 35(1): 157-165. marzia, r., m.a.r. sarkar and s.k. paul. 2016. effect of row arrangement and integrated nutrient management on the yield of aromatic fine rice (cv. brri dhan34). intl. j. plant soil sci. 13(5): 1-8. mobasser, h.r., d.b. tari, m. vojdani, r.s. abadi and a. eftekhar. 2007. effect of seedling age and planting space on yield and yield components of rice (cv. neda). asian j. plant sci.6 (2): 438-440. moe, k., s.m. moh, a.z. htwe, y. kajihara and t. yamakawa. 2019. effects of integrated organic and inorganic fertilizers on yield and growth parameters of rice varieties. rice sci. 26(5): 309-318. mollah, m.r.a., n. islam, and m.a.r. sarkar. 2011. integrated nutrient management for potatomungbean-t. aman rice cropping pattern under level barind agro-ecological zone. bangladesh j. agril. res. 36(4): 711-722. mondal, s. and s.n. swamy. 2003. effect of time on n application yield and yield attributes of rice (oryza sativa l.) cultivar. env. ecol.21(2):411-413. mythili, s., k. natarajan and r. kalpana. 2003.integrated nutrient supply system for zinc and sulphur in lowland rice. agril. sci. digest.23(1): 26-28. obulamma, u., r. reddepa and r. reddy. 2002. effect of spacing and seedling number on growth and yield of hybrid rice. j. res. angrau. 30(1): 76-78. patra, a.k. and b.c. nayak. 2001. effect of spacing on rice varieties of various duration of seedlings on productive tillers, spikelet sterility, grain yield and harvest index of hybrid rice. intl. rice res. notes, 27(1): 51. pol, p.p., a.j. dixit and s.t. thorat. 2005. effect of integrated nutrient management and plant densities on yield attributes and yield of sahayadri hybrid rice. j. maharashtra agric. univ. 30(3): 357-359. salem, a.k.m., w.m. elkhoby, a.b abou-khalifa and m. ceesay. 2011. effect of nitrogen fertilizer and seedling age on inbred and hybrid rice varieties. american-eurasian agri. env.sci.11:640646. sarkar, s.k., m.a.r. sarkar, n. islam and s.k. paul. 2014.yield and quality of aromatic fine rice as affected by variety and nutrient management. j. bangladesh agril. univ. 12(2): 279-284. sarker, d., s. mazumder, s. kundu, f. akter and s.k. paul. 2015. effect of poultry manure incorporated with nitrogenous and sulfur fertilizer on the growth, yield, chlorophyll and nutrient contents of rice var. brri dhan33. bangladesh agron. j. 18(1): 99-111. sharada, p. and p. sujathamma. 2018. effect of organic and inorganic fertilizers on the quantitative and qualitative parameters of rice (oriza sativa l.). current agri. res. 6(2): 12-19. doi : http://dx.doi.org/10.12944/carj.6.2.05. singh, y. and u.s. singh. 2008.genetic diversity analysis in aromatic rice germplasm using agro morphological traits. j. pl. genet. resour. 21(1): 32-37. improving yield performances of late transplant aman rice 11 sreelatha, t., a.s. raju and a.p. raju. 2006. effect of different doses of farm yard manure and poultry manure and their interaction with fertilizer nitrogen on yield and nutrient uptake in mesta-rice cropping system. j. res. angrau. 34(1): 41-47. subhendu, m., s.n. salamy and s. mandal. 2003. effect of time on nitrogen application on yield and yield attributes of rice (oryza sativa l.) cultivars. env. ecol. 21(2): 411-413. subudhi, k.k.m., j. sehgal, w.e. blum and k.s. gojbhiya. 2006. integrated use of organic manures and chemical fertilizer in red soils for sustainable agriculture. red lat. soils. 4(1): 367376. tyeb, a., m.a. samad and s.k. paul. 2013. growth of transplanted aman rice as affected by variety and spacing. bangladesh j. env. sci.(24): 103-108. verma, a.k., n. pandey and s. tripathi. 2002. effect of transplanting spacing and number nitrogen fertilizer and row spacing. indian j. agril. sci.74(3): 144-146. wang, j.l., z.j. xu and x.z. yi. 2006. effect of seedling quantity and row spacing on the yield and yield components of hybrid and conventional rice in northern china. chinese j. rice sci. 20(6): 631-637. wikipedia. 2019a. poultry manure, properties, benefits, operation and maintenance. retrieved from https://en.wikipedia.org/wiki/poultrymanure. wikipedia.2019b. vermicompost, properties, benefits, operation and maintenance. retrieved from https://en.wikipedia.org/wiki/vermicompost. bangladesh agron. j. 2022, 25(1): 15-22 morpho-physiological responses of soybean varieties to salinity stress s.n. mahfuza1, a.f.m.s. ahsan1, i. m. ahmed1, f. ahmed2, a.h.m.m. rahman talukder1 and m.n. islam3 1senior scientific officer,2chief scientific officer, plant physiology division, bari, gazipur-1700, bangladesh 3senior scientific officer, seed technology division, bari, gazipur-1700, bangladesh corresponding e-mail: snmagro1977@gmail.com (received: 23 february 2022, accepted: 28 april 2022) keywords: soybean, salinity, ion uptake, h2o2 and mda contents abstract soybean (glycine max l. merr) has a tremendous value in agriculture as a good source of high-quality plant protein and vegetable oils in one hand and nitrogen fixing ability on the other, now a day largely growing in coastal salt marshes areas of bangladesh. the aim of this study was to evaluate morphological and physiological responses of soybean varieties (shohag, bari soybean-6, bari soybean-5 and binasoybean-4) to pot grown plants in different concentrations of salinity level i.e., control (0.3), 4, 8 and 12 ds m−1 during 2020-21. irrespective of the variety, with the increase of salinity levels physiological parameters as well as seed yield were greatly affected. salinity stress decreased total chlorophyll (chl a+b) and total dry matter (tdm) was reduced due to salinity stress, which ultimately reduced seed yield irrespective of the variety. sodium (na+), calcium (ca2+), potassium (k+) ion content and the potassium sodium ratios (k+: na+) in leaf tissue were significantly affected by salinity levels. under salinity stress, bari soybean6 showed a higher k+: na+ ratio in leaf, which indicates higher tolerance to salinity compared to others. however, h2o2 and mda contents was comparatively lower in the respective variety. this variety also showed higher tdm production, filled pods plant-1 and seed yield plant-1 in all salinity levels compared to other varieties. results revealed that, soybean var. bari soybean-6showedmore tolerance against salinity stress compared to other varieties. introduction soybean (glycine max l. merr) is a major source of high-quality protein and oil for human consumption (katerji et al., 2000). soybean has become an important crop in bangladesh for its increasing demand as an ingredient in poultry and fish meal. salinity stress is the most damaging stress, and rising soil salinity in coastal areas has heightened concern about the possibility of crop damage in fields near the sea. in bangladesh, 2.85 million hectares area of coastal and off-shore are affected by varying degrees of soil salinity with ph ranges of 6.0-8.4 which is composed of the interface of various ecological and economic systems, including mangroves, tidal flat (ahmad, 2019; haque, 2006). salinity problem has been increasing in bangladesh, and over the last 35 years, salinity has increased by around 26 percent in the coastal region of bangladesh (mahmuduzzaman et al., 2014). due to severe and moderate salinity affect crop growth is hampered in this area because soil salinity affects every aspect of plant growth and development. the inhibition of plant growth due to salinity is attributed to salt-induced ion toxicity, nutrient deficiencies, salt-induced osmotic stress, hormonal imbalance, and salt-induced oxidative stress. salinity also caused a drastic reduction in grain yield of many crops including soybean (khan et al., 2016), mungbean (aziz et al., 2005), and peas (duzdemir et al., 2009). since, the growth, development, and yield of a crop are the product of genetic potential interacting with the environment, soybean seed production may be 16 mahfuza et al. limited by soil salinity (ghassemi-golezani et al., 2009). growing salt-tolerant crop or variety is one of the cost-effective strategies for coping with soil salinity. the comparison of the performance of different cultivars under salinity stress is useful to select the best one for cultivation to minimize the yield loss. this study was undertaken to investigate the morpho-physiological basis of salinity tolerance of soybean varieties and their comparative salinity tolerance would help to identify the most salt-tolerant variety and to increase soybean productivity in the saline soils of bangladesh. materials and methods a pot experiment was conducted at the vinyl house of plant physiology division, bari, gazipur during rabi season of 2020-21. four variety namely: shohag, bari soybean-6, bari soybean-5 and binasoybean-4, were tested under four salinity levels (control, 4, 8 and 12 ds m-1). salinity was imposed at 30 days after sowing (das) by adding nacl solution. salt solution was prepared by dissolving calculated amount of lab-grade nacl with pond water. salt solution was applied with an increment of 4 ds m-1 in every alternate day until desired salinity levels were attained. in control treatment, pond water was used which salinity levels was 0.3 ds m-1. salinity levels were maintained by monitoring and adding salt solution when require up to maturity. the experiment was laid out in randomized complete block design with 3 replications. plastic pots (top dia: 25 cm, bottom dia: 18 cm and height 25 cm; 12 kg soil) was filled up with soil and cow dung (4:1). seeds were sown in each pot on 29 november 2020. fertilizers were applied @30-30-80-20-3-1 kg-1 ha npksznb (fgr, 2018) in the form of urea, triple super phosphate (tsp), muriate of potash (mop) gypsum, zinc sulphate and boric acid respectively. half of n and all other fertilizers were applied as basal and remaining n was applied at 30 days after sowing (das). irrigation was done as and when required for maintaining adequate soil moisture. after emergence plants were thinned to three plants in each pot. plants from three pots were sampled for leaf area and dry matter measurement at reproductive stages. plant parts were dried in an oven for 72 hours at 70 ○c and dry weight was recorded. at harvest yield and yield components data were collected from three pots and analyzed statistically and mean separation was done by lsd test at 5% level of significance using data processing software. chlorophyll estimation leaves of each variety were properly cut into small pieces and weighed 0.5 g and were taken for chlorophyll estimation at 55 das. chlorophyll a, chlorophyll b and total chlorophyll were estimated following arnon’s method (arnon, 1949). the absorbance of the solution was read at 645 and 663 nm for chlorophyll a, chlorophyll b and total chlorophyll. calculation: chlorophyll a (mg g-1) = {12.7 (d663) 2.69 (d645)}  v/(1000  w) chlorophyll b (mg g-1) = {22.9 (d645) 4.68 (d663)}  v/(1000  w) total chlorophyll (mg g-1) = chl. a+ chl. b where, d = optical density; v = final volume of 80% acetone (ml); w = fresh weight of sample taken (g) sodium, potassium and calcium ion uptake measurement at 45 das, fully expanded third leaf from top was collected from each treatment for determination of sodium and potassium ion content in leaf tissue. cell sap of leaf was extracted from leaf using mortar and pistil. laqua twin sodium ion meter (na-11, horiba, japan) laqua twin calcium ion meter (ca-11, horiba, japan) and laqua twin potassium ion meter (k-11, horiba, japan) were used for na+, ca2+ and k+ determination, respectively. measurement of lipid peroxidation (mda) the level of lipid peroxidation was measured by estimating mda, a decomposition product of the peroxidized polyunsaturated fatty acid component of the membrane lipid, using thio barbituric acid morpho-physiological responses of soybean to salinity stress 17 (tba) as the reactive material following the method of heath and packer (1968). briefly, the leaf tissue (0.5 g) was homogenized in 3 ml 5% (w/v) trichloro acetic acid (tca), and the homogenate was centrifuged at 11,500×g for 10 min. the supernatant (1 ml) was mixed with 4 ml of tba reagent (0.5% of tba in 20% tca). the reaction mixture was heated at 95ºc for 30 min in a water bath and then quickly cooled in an ice bath and centrifuged at 11,500×g for 15 min. the absorbance of the colored supernatant was measured at 532 nm and was corrected for non-specific absorbance at 600 nm. the concentration of mda was calculated by using the extinction coefficient of 155 mm−1 cm−1 and expressed as nmol of mda g-1 fw. measurement of h2o2 hydrogen peroxide was assayed according to the method described by yu et al. (2003). the extraction of h2o2 was done by homogenizing 0.5 g of leaf tissue with 3 ml of 50 mm k-phosphate buffer (ph 6.5) at 4ºc. the homogenate was centrifuged at 11,500×g for 15 min. the supernatant (3 ml) was mixed with 1 ml of 0.1% ticl4 in 20% h2so4 (v/v), and the mixture was then centrifuged at 11,500×g for 15 min at room temperature. the optical absorption of the supernatant was measured spectrophotometrically at 410 nm to determine the h2o2 content (є= 0.28 μm−1 cm−1) and expressed as nmolg-1 fw. the data on different parameters were analyzed statistically by using statistix 10 program. the mean separation was done by the lsd at 5% level of probability. results and discussion effect of salinity levels on pigment contents photosynthetic pigment contents sharply decreased with increase in salinity levels in all the varieties (figure 1a). pigment contents were higher in bari soybean-6 in all the salinity levels and lower in shohag. total chlorophyll content of bari soybean-6decreased 4,6and 11%, under 4,8 and 12ds m1salinity stresses, respectively which was comparatively lower than other three varieties. this result was also in agreement with mannan and karim (2011). netondo et al. (2004) also observed that photosynthetic activity decreases when plants are grown under saline conditions leading to reduced growth and productivity. the reduction in photosynthesis under salinity can be attributed to a decrease in chlorophyll content (jamil et al., 2007) and activity of photo-system ιι (ganivea et al., 1998). total dry matter (tdm) tdm in all the salinity treatments sharply decreased at all the studies soybean varieties (figure 1b). the tdm of shohag (sensitive to salt) decreased about 27, 46 and 68% in 4, 8 and 12 ds m-1 salinity stresses, respectively against control (no salinity). tdm reduction of binasoybean-4 was about 19, 33, and 57% in 4, 8 and 12 ds m-1 salinity stresses respectively whereas in bari soybean-5, the reduction was 16, 33 and 47% in 4,8 and 12 ds m-1 salinity stresses, respectively, then the control (no salinity) which leads it to the second position of the studied varieties. however, the maximum tdm production was found in bari soybean-6 variety under all salinity levels. dolatabadian et al. (2011) and kondetti et al. (2012) noticed plant height and total biomass significantly decreased due to salinity. plant height the effects of salt stress on the morphological characteristics of four treated soybean varieties were evaluated. plant height of shohag, bari soybean-6, bari soybean-5 and binasoybean-4 were significantly reduced by increasing salinity levels (figure 1c). in the present study, plant height decreased in all the varieties with increasing intensity of salinity. however, in all the salinity levels, relatively higher plant height was observed in bari soybean-6, which was significantly higher than the other three varieties. on the other hand, relatively lower plant heights were recorded in shohag, which was followed by binasoybean-4 in all the salinity levels. 18 mahfuza et al. number of filled pod plant-1 number of filled pod plant-1 of the varieties varied significantly (figure 1d). under control condition, the highest number of filled pod plant-1 was observed in bari soybean-6, which was identical with shohag and bari soybean-5 but differed from binasoybean-4. moreover, under 4, 8 and 12 ds m-1 salinity level higher number of filled pod plant-1 was recorded in bari soybean-6 and shohag gave the lower number of filled pod plant-1 under all salinity level. fig.1. effect of salinity levels on total chlorophyll (a) total dry matter (b) plant height (c) and no. of filled pod plant -1(d) of soybean varieties. bars indicate se values. effect of salinity levels on sodium (na+), potassium (k+) content, calcium (ca+) content and k+: na+ ratio the amount of na+, k+, k+: na+ ratio and ca+ accumulated in the leaves of soybean varieties (shohag, bari soybean-6, bari soybean-5 and binasoybean-4) are shown in figure 2a-d. in the present study, sodium (na+) content increased in all the varieties with salinity intensity. increasing rate was significantly higher in shohag leaves than rest of the varieties. in shohag leaves, na+ content increased 31, 97 and 142%, in 4, 8 and 12 ds m-1 salinity stress, respectively, which was significantly higher than other varieties. comparatively, increasing rate of na+ content was less in bari soybean-6, which was followed by bari soybean-5 and binasoybean-4. 0.00 0.50 1.00 1.50 2.00 control 4 ds 8 ds 12 ds t o ta l ch lo ro p h y ll ( m g g -1 f w ) a shohag bari soybean-6 bari soybean-5 bina soybean-4 0 5 10 15 20 control 4 ds 8 ds 12 ds t o ta l d ry m at te r (g p la n t-1 ) b 0 10 20 30 40 50 60 70 control 4 ds 8 ds 12 ds p la n t h ei g h t (c m ) salinity level c 0 10 20 30 40 50 60 control 4 ds 8 ds 12 ds n o . o f fi ll ed p o d p la n t-1 salinity level d morpho-physiological responses of soybean to salinity stress 19 fig. 2. effect of salinity levels on na+(a), k+(b), ca2+ (c) and k+: na+ (d) ratio in the leaves of soybean varieties. bars indicate se values. potassium (k+) content showed the reverse effect on na+ content which means that decreasing trend with increasing salinity level (figure 2b). the k+ content is the main cation in plants and is an important component of the cell osmotic potential (reggiani et al., 1995). the results were supported by reports of essa (2002) and sobhanian et al. (2010). on the other hand, k+: na+ ratio decreased significantly with salinity levels in all varieties (figure 3d). bari soybean-6 showed higher potassium/sodium ratio than shohag, bari soybean-5and binasoybean-4in all the salinity treatments. ca2+ contents in leaf decreased with increased salinity levels (figure 3c). the variety bari soybean6 maintained a higher ca2+ under all salinity levels than the other three varieties. essa (2002) reported that the main response of the plant to salt stress is a change in ca2+ homeostasis and attributed that the salt tolerance of plants is their ability to avoid na+ toxicity and to maintain ca2+ and k+ concentrations. according to mannan et al. (2013), the relatively high salt tolerance of ags 313 was associated with the limited accumulation of sodium and high accumulation of different mineral ions in different plant parts, as well as the maintenance of better water relations under salinity than in the case of shohag. in the present study, na+ ion was increased, k+ and ca2+ ion decreased in all varieties with increasing salinity stress, which is a common phenomenon in all plants. the accumulation of na+ ion might be involved in the osmotic adjustment. in this experiment, k+: na+ ratio was higher in bari soybean-6. 0 20 40 60 80 100 control 4 ds 8 ds 12 ds n a+ p p m a shohag bari soybean-6 bari soybean-5 bina soybean-4 0 500 1000 1500 2000 2500 3000 3500 control 4 ds 8 ds 12 ds k + p p m b 0 200 400 600 800 1000 1200 1400 1600 control 4 ds 8 ds 12 ds c a2 + p p m salinity level c 0 20 40 60 80 100 120 control 4 ds 8 ds 12 ds k + : n a+ salinity level d 20 mahfuza et al. effect of salinity levels on h2o2 and mda content h2o2 contents significantly increased in soybean varieties with salinity stress compared with the control (figure 3a). however, the increment of h2o2 contents was lower in bari soybean-6 than rest of the varieties. at 12 dsm-1 salinity level, the content of h2o2 increased by 3.55 folds, in the leaves of bari soybean-6, while h2o2 content increased by 4.36 folds, in shohag over their control. salinity stress effect on lipid peroxidation was determined as the presence of malondialdehyde (mda) in soybean leaf tissues. the amount of mda significantly increased in the soybean seedlings compared to control when exposed to salinity. the increase rate of mda in shohag was higher than in the rest soybean varieties (figure 3b). the contents of mda were 143,159 and 166% higher at 12 ds salinity stress in bari soybean-6, bari soybean-5, and binasoybean-4compared to their control whereas, in case of shohag mda content was189% higher than their respective control in the same situation. fig. 3. effect of salinity levels on h2o2 (a) and mda (b) content of soybean varieties. bars indicate se values. seed yield plant-1 seed yield, which is the ultimate goal is very sensitive to salinity conditions. reduction percentage of seed yield plant-1 was higher at higher salinity levels compare to control and gradual increased in reduction in seed yield was obtained with the increment of salinity (fig 4). the seed yield of soybean varieties was varied significantly among the treatment combinations. the seed yield reduction percentage was higher in shohag which was 20, 43 and 62% in 4,8 and 12 dsm-1 salinity stresses, respectively compared with control. on the other hand, bari soybean-6 showed relatively lower seed yield reduction i.e., 6, 28 and 38% in 4,8 and 12 ds m-1 salinity stresses, respectively compared with control. bari soybean-5and binasoybean-4 gave moderate seed yield in all salinity level compared with control. 0 10 20 30 40 50 60 70 control 4 ds 8 ds 12 ds h 2 o 2 ( n m o l g -1 fr es h w ei g h t) salinity level a shohag bari soybean-6 bari soybean-5 bina soybean-4 0 10 20 30 40 50 60 70 control 4 ds 8 ds 12 ds m d a ( n m o l g -1 fr es h w ei g h t) salinity level b morpho-physiological responses of soybean to salinity stress 21 fig. 4. effect of salinity levels on seed yield plant-1 of soybean varieties. bars indicate se values. conclusion the result showed that plant biomass, higher k+ concentration, k+: na+ ratio, h2o2 and malondialdehyde (mda) contents as well as yield contributing characters and seed yield as indices of salinity stress tolerance, it has exebit that soybean var. bari soybean-6 is relatively tolerant to salinity stress, than the other three varieties. references ahmad, h. 2019. bangladesh coastal zone management status and future trends. j. coast. zone mngt. 22(1): 1-7. arnon, d.i. 1949. copper enzymes in isolated chloroplasts. polyphenoloxidase in beta vulgaris. plant physiol. 24(1): 1. aziz, m.a., m.a. karim, m.a. hamid, q.a. khalique and m. hossain. 2005. salt tolerance in mungbean: growth and yield response of some selected mungbean genotypes to nacl salinity. bangladesh j. agric. res. 30: 529-535. dolatabadian, a., s.a.m.m. sanavy and f. ghanati. 2011. effect of salinity on growth, xylem structure and anatomical characteristics of soybean. not. sci. biol. 3(1): 41-45. duzdemir, o., a. kurunc and a. unlukara. 2009. response of pea (pisum sativum) to salinity and irrigation water regime. bulgarian j. agric. sci. 15(5): 400-409. essa, t.a. 2002. effect of salinity stress on growth and nutrient composition of three soybean (glycine max l. merrill) cultivars. j. agron. crop sci. 188(2): 86-93. frg. 2018. fertilizer recommendation guide, bangladesh agricultural research council (barc). farmgate, new airport road, dhaka. ganieva, r.a., s.r. allahverdiyev, n.b. guseinova, h.i. kavakli and s. nafisi. 1998. effect of salt stress and synthetic hormone polystimuline k on the photosynthetic activity of cotton (gossypium hirsutum). turkish j. bot. 22(4): 217-222. ghassemi-golezani, k., m. taifeh-noori, s. oustan and m. moghaddam. 2009. response of soybean cultivars to salinity stress. j. food agric. environ. 7(2): 401-404. haque, s.a. 2006. salinity problems and crop production in coastal regions of bangladesh. pakistan j. bot. 38(5): 1359-1365. 0 2 4 6 8 10 12 14 16 control 4 ds 8 ds 12 ds s ee d y ie ld ( g p la n t-1 ) salinity level shohag bari soybean-6 bari soybean-5 bina soybean-4 22 mahfuza et al. heath, r.l. and l. packer. 1968. photoperoxidation in isolated chloroplasts: i. kinetics and stoichiometry of fatty acid peroxidation. arch. biochem. biophys. 125(1): 189-198. jamil, m., k.j. lee, j.m. kim, h.s. kim and e.s. rha. 2007. salinity reduced growth ps2 photochemistry and chlorophyll content in radish. scientia agricola, 64: 111-118. katerji, n., j.w. van hoorn, a. hamdy and m. mastrorilli. 2000. salt tolerance classification of crops according to soil salinity and to water stress day index. agric. water mng. 43(1): 99-109. khan, m.s.a., m.a. karim, m.m. haque, m.m. islam, a.j.m.s. karim and m.a.k. mian. 2016. influence of salt and water stress on growth and yield of soybean genotypes. pertanika j. trop. agric. sci. 39(2): 167 – 180. mahmuduzzaman, m., z.u. ahmed, a.k.m. nuruzzaman and f.r.s. ahmed. 2014. causes of salinity intrusion in coastal belt of bangladesh. int. j. plant res. 4(4a): 8-13. mannan, m.a., m.a. karim, m.m. haque, q.a. khaliq, h. higuchi and e. nawata. 2013. response of soybean to salinity: iii. water status and accumulation of mineral ions. trop. agr. develop. 57(1): 41-48. mannan, m.a. and m.a. karim. 2011. mechanisms of salinity tolerance in soyabean. bangladesh agron. j. 14(1&2): 85-93. netondo, g.w., j.c. onyango and e. beck. 2004. sorghum and salinity: ii. gas exchange and chlorophyll fluorescence of sorghum under salt stress. crop sci. 44(3): 806-811. reggiani, r., a. bertani and s. bozo. 1995. the effect of salinity on early seedling growth of seeds of three wheat (triticum aestivum l.) cultivars. canadian j. plant sci. 75(1): 175-177. sobhanian, h., r. razavizadeh, y. nanjo, a.a. ehsanpour, f.r. jazii, n. motamed and s. komatsu. 2010. proteome analysis of soybean leaves, hypocotyls and roots under salt stress. proteome sci. 8(1): 115. thomas, j.m.g., k.j. boote, l.h. allen, m. gallo‐meagher and j.m. davis. 2003. elevated temperature and carbon dioxide effects on soybean seed composition and transcript abundance. crop sci. 43(4): 1548-1557. yu, c.w., t.m. murphy and c.h. lin. 2003. hydrogen peroxide-induced chilling tolerance in mung beans mediated through aba-independent glutathione accumulation. func. plant biol. 30(9): 955-963. bangladesh agron. j. 2020, 23(2): 1-12 production potential and weed dynamics in maize + legumes intercropping system q. naher*, s.m.r. karim 1 , m. begum 1 and m.a. hossain* *onfarm research division, bangladesh agricultural research institute, joydebpur, gazipur 1701, bangladesh 1 professor, agronomy division, bangladesh agricultural university, mymensingh corresponding email: ofrdjoy@yahoo.com (received: 03 september, 2020, accepted: 26 september, 2020) keywords: maize, legume, intercropping, productivity, competitive ability abstract the experiment was carried out at the bangladesh agricultural research institute, gazipur during summer season of 2012 to identify suitable legume crops for growing with maize in a maize + legume intercropping system for better weed suppression, system productivity and economic benefits in kharif season. there were 17 treatments, viz.t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free), t15= sole mungbean (weed free), t16= sole soybean (weed free) and t17= sole blackgram (weed free) were studied. intercropping systems significantly reduced the weed population and weed dry biomass in comparison to sole cropping of maize under unweeded situation. among the three different intercropping systems, maize + mungbean with two hand weedings produced the lowest weed dry weight (184.30 g at 20 dae and 14.07 g at 40 dae) and the highest weed control efficiency (87% at 40 dae) followed by maize + soybean and maize + blackgram intercropping systems. the highest grain yield was obtained from weed free sole maize (8.05 t ha -1 ) than unweeded sole maize (6.48 t ha -1 ) treatment. among all intercropping, maize + mungbean along with two hand weedings gave the highest yield (maize: 7.18 t ha -1 ; 572.6 kg ha -1 mungbean), resource complementarity and profitability (mey = 10.62 t ha -1 , ler = 1.81 and bcr = 2.47). from the study it was concluded that maize + mungbean with two hand weedings at 20 and 40 dae would be the best in reducing weed growth, producing maximum yield and getting net return in intercropping systems during kharif season. introduction maize (zea mays l.) is one of the most versatile emerging crop having wider adaptability under varied agro-climatic conditions. globally, maize is known as queen of cereals because it has the highest genetic yield potential among the cereals. it is a source of carbohydrate and used for both human consumption and animal feed worldwide due to its high feeding value (undie et al., 2012). wide range of weed flora invades maize crop and causes yield losses ranging from 34 to 67% and sometimes even more (kumar and thakur, 2005). weed management is, therefore, very important aspect to augment maize production. the wider row spacing in maize can be used to grow legumes which not only will act as a smoother crop but will give additional yield. mungbean, soybean and blackgram as a potential kharif legumes of bangladesh can be mailto:ofrdjoy@yahoo.com 2 naher et al. successfully intercropped with maize provided effective weeds control. kharif maize suffers from severe weed competition and depending upon the intensity, nature, stages and duration of weed infestation, it causes yield losses from 28-100% (patel et al., 2006). katsaruware and manyanhaire (2009) concluded that maize-cowpea intercrops reduced weed biomass when compared to sole crops. intercropping is a practice of growing of two or more, generally, dissimilar crops simultaneously on the same piece of land with distinct row arrangement. with the rapid population increase, the demand for food has been increasing while land availability has been declining. thus, the only way to increase agricultural production is to increase yield per unit area (odedina et al., 2014). legumes in maize based cropping systems are considered to be better alternatives for securing nitrogen economy and increasing yield of maize besides bonus yield, greater productivity per unit time and space and higher net returns of intercropping system over monoculture. this practice is an attractive strategy to smallholder farmers for increasing productivity, utilization of land and labour though intensification of land uses (seran and brintha, 2010). it can suppress the weed growth more than the sole crops (baumann et al., 2000). weed management is commonly very labor intensive in small-holder agriculture, often constrains the land area that can be farmed, and inadequate weed control is often a major constraint yield (wortmann et al., 2009). crop suppression of weeds is an important component of weed management. weeds are commonly more suppressed by crop competition in intercropping compared to sole cropping (getachew et al., 2007). intercropping of short-duration crops like cowpea, blackgram, greengram or sesbania between maize rows has been found quite effective in weed suppression. since maize is grown in wide spaced rows, the short duration varieties of pulses and oilseeds can be intercropped with it successfully. intercrop efficiency with varying levels of weed management has not been well studied for the maize–bean intercrop. the objective of this study was, therefore, to evaluate weeding and legumes effect in maize–legume intercropping on weed suppression, and the agronomic and economic efficiency of intercropping. materials and methods the experiment was conducted at the on-farm research field of bangladesh agricultural research institute, joydebpur, gazipur during kharif season of 2012. the experiment site was located at chhiata series under agro-ecological zone-28. before opening the land, the soil samples were taken from the spots of the experimental area and analyzed from the soil science division, bari. the soil analysis showed that the soil of the experimental field was loam in texture and low in organic matter (1.16%). the soil ph is 7.2 and contained very low amount of total nitrogen (0.061%), phosphorus (3 g/g), sulphur (0.6 g/g), zinc (3.54 g/g), boron (0.44 g/g) and potassium (0.13 meq./100g soil). during the period of experimentation the maximum and minimum temperature ranged from 27.1°c to 35.5°c and 21.4°c to 25.4°c, respectively. crops received total 201.4 and 240.1 mm rainfall distributed during marchto july in 2012. there were 17 treatments viz., t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 = sole maize (weed free), t15= sole mungbean (weed free) , t16= sole soybean (weed free) and t17= sole blackgram (weed free) were studied. maize was sown in 75 cm × 20 cm spacing both in sole and intercrop system. mungbean, blackgram and soybean were sown in 30 cm × 10 cm spacing in sole and intercrop situation. planting arrangement in intercrop treatments, two rows of legumes accommodated between one row of maize. the trials were laid out in a randomized complete block design with three replications. the plot size was 5.0m ×4.5m. maize variety bari hybrid maize-7, mungbean variety bari mung-5, blackgram variety bari mash-3 and production potential and weed dynamics in maize 3 soybean variety bari soybean-5 were used as test crops. fertilizer was applied for maize at the rate of 250-50-100-44-5-2 kg of n, p, k, s, zn and b ha -1 , respectively, from urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid, respectively. half amount of n and full dose of other fertilizers were incorporated into the soil at the time of final land preparation. the remaining urea was top dressed in two equal installments at 8-10 leaf stage (30-35 das) and at tasseling stage (50-60 das) followed by irrigation. the fertilizer doses for grain legumes were 21-17-18 and 23-18-18 kg of n, p, k ha -1 , respectively from urea, tsp, mop, respectively. in case of sole cropping of legumes, the entire fertilizers were applied. sowing of both maize and legumes were done on 15 march 2012. weed management was done as per treatment specification. mature mungbean and blackgram were harvested at 65 dae while soybean was harvested at 100 dae. maize was harvested at 120 dae. maize equivalent yield was computed using the formula of bandyopadhaya (1984). maize equivalent yield= yim + (yil pl)/pm where, yil = yield of intercrop legume (t ha -1 ) yim = yield of intercrop maize (t ha -1 ) pm = selling price of maize pl = selling price of legume weed control efficiency (wce) was calculated using the following formula (curz et al., 1986). land equivalent ratio (ler) land equivalent ratio (ler) was obtained according to willey (1979) as follows: ler = crop sole as legume of yield intercrop as legume of yield crop sole as maize of yield intercrop as mazie of yield  competitive ratio (cr) (willey and rao, 1980) competitive ratio of maize: (crm) :{(yim/ysm)/yil/ysl)}  (zl/zm) competitive ratio of legume: (crl) : {(yil/ysl)/(yim/ysm)}  (zm/zl) where, ysm = yield of sole maize ysl = yield of sole legume yim = yield of intercrop maize yil = yield of intercrop legume zi = proportion of legume in intercrop zm = proportion of maize in intercrop wce = 100 dwc dwt-dwc  dwc = dry weight of weeds in the weedy check dwt = dry weight of weeds in the weeding treatment the collected data were statistically analyzed by using mstat programme and the means were adjudged by using lsd. economic analysis was also done. results and discussion weed density, weed dry weight and weed control efficiency (wce) were affected by different intercropping system and weeding regime is presented in table 1. intercropping systems significantly reduced the weed population and weed dry biomass than sole cropping of maize under unweeded situation. cynodon dactylon, eleusine indica, echinochloa crusgalli, paspalum conjugatum, cyperus rotundus l. and physalis heterophyll were the common and dominant weeds in the maize field. in kharif season, weed density, weed dry weight and weed control efficiency (wce) were recorded at 20 dae and 40 dae. maximum weed density (363.3 no. m -2 at 20 dae and 426 m -2 at 40 dae) and 4 naher et al. weed dry weight (216.8g at 20 dae and 284.4g at 40 dae) were recorded in unweeded monocultured maize crop. among the three different intercropping systems, t5 (maize + mungbean with two hand weedings at 20 and 40 dae) treatment provided the lowest weed density (275.3 m -2 at 20 dae and 53.33 m -2 at 40 dae) and weed dry weight (184.3 g at 20 dae and 14.07 g at 40 dae) and it was followed by maize + soybean and maize + blackgram (table 1). table 1. weed density, weed dry weight and weed control efficiency (%) in different maize + legumes intercropping systems during the kharif season of 2012 treatments weed density (no. m-2) weed dry weight (g m-2) weed control efficiency (%) 20 dae 40 dae 20 dae 40 dae 20 dae 40 dae t1 363.30 426.00 216.80 284.40 t2 284.70 324.30 190.50 178.00 21.32 23.84 t3 283.00 113.00 189.10 25.61 21.82 73.40 t4 270.70 326.30 181.20 157.90 25.25 23.27 t5 275.30 53.33 184.30 14.07 24.05 87.53 t6 293.30 330.70 196.30 182.60 18.83 22.34 t7 286.00 85.67 192.20 35.17 21.12 79.82 t8 289.30 333.30 193.70 163.90 20.13 21.65 t9 291.00 62.00 194.80 17.50 19.55 85.46 t10 310.00 330.30 207.50 181.20 14.13 22.38 t11 280.70 64.00 187.80 17.67 22.42 84.96 t12 277.30 349.30 185.60 179.60 23.46 17.87 t13 290.30 99.33 190.30 38.50 19.82 76.71 lsd(0.05) 20.37 22.54 11.75 8.90 4.97 6.04 cv (%) 4.48 6.49 8.32 3.10 13.99 6.91 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free) , t15= sole mungbean (weed free) , t16= sole soybean (weed free) and t17= sole blackgram (weed free) this was probably due to more shading effect of mungbean canopy owing to more number of mungbean plants per unit area (pandey and prakash, 2002 and dwivedi and shrivastava, 2011). at 20 dae, the wce in all the treatments was almost same while at 40 dae the wce varied significantly in all treatments. weed control efficiency of different treatments varied from 14.8-25.3% at 20 dae and 17.9-87.53% at 40 dae, respectively. among the weed control treatments, two hand weeding at 20 and 40 dae in maize + mungbean caused the highest weed control efficiency (24.0-87.5%) while it was 19.55-85.46% in maize + soybean and 19.82-80.09% in maize + blackgram treatments. the reduction in weed population and weed dry biomass in intercropping systems may be attributed to shading effect and competition stress created by canopy of more number of crop plants in a unit area having suppressing effect on associated weeds thus preventing the weeds to attain full growth. similar results were reported by pandey and prakash (2002) that maize and legume intercropped either as paired rows + two rows of legume or one row of legume in between two rows of maize adversely affected the weed growth and caused 22.4 and 31.9% weed growth suppression as compared to sole maize, respectively . khan et al. (2011) evaluated the effect of weed control on production potential and economics of maize (zea mays l.)legume intercropping system. among the intercropping systems, t10 (maize + blackgram no weeding plot ) gave lower wce (14.13-22.38%). production potential and weed dynamics in maize 5 yield and yield attributes of maize yield and yield contributing characters were influenced significantly by different intercropping systems and weeding regimes in kharif season (table 2). the maximum cob length of maize was found in sole maize (16.80 cm) and maize + mungbean intercropping t5 (16.67 cm). table 2. yield attributes of maize in maize + legumes intercropping system during the kharif season of 2012 treatments cob length (cm) grains cob-1 (no.) 1000-grain wt. (g) t1 16.80 486.30 273.70 t2 15.53 459.00 260.50 t3 15.48 473.00 272.4 0 t4 15.95 484.00 268.3 0 t5 16.67 501.00 277.5 0 t6 15.13 432.00 263.2 0 t7 15.73 440.70 269.7 0 t8 15.97 473.00 267.9 0 t9 15.83 474.70 267.1 0 t10 15.07 436.00 264.4 0 t11 15.50 440.00 265.8 0 t12 15.92 471.70 269.1 0 t13 15.90 478.7 0 272.00 t14 17.70 554.00 276.9 0 lsd(0.05) 1.097 38.60 5.266 cv (%) 4.10 4.88 1.17 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) and t14 =sole maize (weed free) the lowest cob length was obtained from no weeding maize + soybean t10 (15.07 cm) condition which was statistically at par with t6 (15.13 cm), treatment. higher number of grains cob -1 was recorded from weed free sole maize (554) treatment. the lower number of grains cob -1 was observed in no weeding maize + soybean (432) and maize + blackgram (436) intercropping system. among the intercropping systems, maize + mungbean with two hand weedings (501) gave higher grains cob -1 than all maize + blackgram and maize + soybean intercropping systems. significant influence was observed in 1000grain weight by the treatments. the highest 1000-grain weight was recorded from maize + mungbean with two hand weedings intercropping system (277.5 g) which was statistically at par with weed free sole maize (276.9 g), no weeding sole maize (273.7 g), one hand weeding at 20 dae maize + mungbean intercropping treatment (272.4 g) and maize + blackgram two hand weedings (272 g) treatments. among the intercropping systems, maize + mungbean was obtained higher grains weight than maize + blackgram and maize + soybean association. significant influence was observed in yield of maize by the different intercropping situations (fig. 1). the highest grain yield was obtained from weed free sole maize (8.05 t ha -1 ) than unweeded sole maize (6.48 t ha -1 ) treatment. the lowest yield showed in unweeded maize plot in all intercropped situation. among the intercropping situation, maize + mungbean with two hand weedings (7.18 t ha -1 ) treatment marked higher grain yield than maize + blackgram (6.55 t ha -1 ) and maize + soybean (6.25 t ha -1 ) 6 naher et al. intercropping systems. higher yield of maize was observed in monoculture compared to their respective intercropped might be due to no intercrop competition for light, nutrients, moisture and space. this corroborates with the findings of quayyum and moniruzzaman (1995) and uddin et al. (2003). they reported that maize yield was found to be highest from sole crop than intercropped with legume. the reduction of maize yield was probably due to intercrop competition between crops and weeds. lower crop-weed competition under two hand weedings might have led to better yield components and thus resulted in higher yield (mundra et al., 2003). fig. 1. grain yield of maize in maize + legumes intercropping system during kharif season of 2012. yield and yield attributes of legumes all the yield characters of legumes were significantly influenced by the treatments of maize + legumes intercropping systems (table 3). higher number of pods plant -1 was recorded in intercropped soybean (80) which was statistically similar with sole soybean (78) and the lowest one was in intercropped mungbean (16.43) that was similar with others mungbean treatments. among the legumes intercropping systems, maize + soybean was found in higher number of pods plant -1 with varying weeding regime (akhteruzzaman and quayyum, 1991) who reported that number of pods plant -1 of legumes were reduced by intercropping in kharif season. the highest seeds pod -1 was obtained in sole legumes, except mungbean. among the intercropping systems, maize + mungbean intercropping gave higher number of seeds pod -1 than other maize + soybean and maize + blackgram intercropping (table 3). maximum 1000-seed weight was observed in soybean mono cropping system which was followed by soybean with two hand weedings in intercropping treatments. the lowest 1000-seed weight was observed in blackgram intercropping treatments. 6.48 4.99 5.65 6.52 7.18 4.98 5.15 5.68 6.25 4.96 5.89 6.30 6.50 8.05 0 1 2 3 4 5 6 7 8 9 g ra in y ie ld ( t h a -1 ) treatments production potential and weed dynamics in maize 7 table 3. yield attributes of legumes in maize + legumes intercropping system during the kharif season of 2012 treatments pods plant-1 (no.) seeds pod-1 (no.) 1000-seed weight (g) t2 16.57 f 12.17 a 36.30 de t3 16.43 f 13.33 a 37.13 c-e t4 16.77 f 13.13 a 38.40 c-e t5 18.83 f 13.53 a 39.63 b-e t6 52.67 c 2.46 c 31.33 f t7 70.67 b 2.433 c 41.00 bc t8 70.33 b 2.467 c 37.33 c-e t9 79.67 a 2.500 c 43.33 ab t10 26.00 e 5.667 b 35.17 ef t11 37.67d 5.667 b 35.27 ef t12 35.43 d 6.000 b 36.07de t13 38.57 d 6.333 b 36.63 c-e t15 18.83 f 12.33 a 40.57 b-d t16 78.33 a 2.933 c 46.00 a t17 47.67 c 6.667 b 39.27 b-e lsd(0.05) 6.244 1.257 3.936 cv (%) 8.97 10.47 6.16 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free) , t15=sole mungbean (weed free) , t16=sole soybean (weed free) and t17= sole blackgram (weed free) seed yield of legumes was influenced by the treatments (fig. 2). sole legumes produced the highest seed yield then it reduced significantly when it was grown in association with maize as intercrop. the higher seed yield produced from maize + mungbean intercropping with two hand weedings (572.6 kg ha -1 ) which was followed by maize + blackgram (510.8 kg ha -1 ) and maize + soybean (502.9 kg ha -1 ) intercropping systems. the lowest yield was obtained by mungbean no weeding treatment (302.4 kg ha 1 ) which was statistically similar with maize + blackgram no weeding (316.6 kg ha -1 ) and maize + soybean no weeding (333.7 kg ha -1 ) treatments. reduced yield of legumes under different intercropping situations was due to less population (67%) compared with sole crop of legumes (100%). besides, legumes yield was poor due to less availability of light and nutrient in intercropping situation and also shading effect of maize. these findings were in accordance to those of torofder et al. (1992) and razzaque et al. (2007). among the intercropped treatments, weeding done twice at 20 and 40 dae resulted higher grain yield of mungbean than one hand weeding and no weeding treatment due to better growth environment. they also reported that, weeding done at 45 days appeared to have an adverse effect on crop yield as it might have distributed the root zone of the plants. a delay in weeding resulted in reduction of crop yield. it also might be due two hand weedings intercropping systems favoured of intercropped mungbean and judicious use of growth resources compared to other intercropped combinations. 8 naher et al. fig. 2. seed yield of legumes in maize + legumes intercropping system during the kharif season of 2012. assessment of competition and evaluation of intercrop productivity competitive ratio index was used to assess the competition effects of maize and component crops in the maize + legume intercropping system.competitive ratio values showed the variability in competitive ability of component crops with the variation of intercropping systems. results showed that all treatments of maize intercropping had higher competitive ability of maize than legumes (table 4).among thethree intercropping systems, maize + soybean and maize + blackgram intercropping association performed better than maize + mungbean intercropping systems. table 4. competitive ratio of maize and legumes in intercropping systems during the kharif season of 2012 treatments competitive ratio maize legumes difference mungbean t2 1.39 0.72 0.67 t3 1.02 0.94 0.08 t4 1.14 0.88 0.26 t5 1.06 0.94 0.12 soybean t6 1.51 0.66 0.85 t7 1.31 0.76 0.55 t8 1.28 0.78 0.50 t9 1.27 0.78 0.49 blackgram t10 1.61 0.62 0.99 t11 1.27 0.79 0.48 t12 1.33 0.75 0.58 t13 1.29 0.78 0.51 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) 302.4 453.3 481.3 572.6 333.7 398.4 447.8 502.9 316.6 477.4 486.4 510.8 817.8 981.7 1048.0 0 200 400 600 800 1000 1200 s e e d y ie ld ( k g h a -1 ) treatments production potential and weed dynamics in maize 9 evaluation of intercrop productivity intercrop productivity was evaluated by equivalent yield, land equivalent ratio and monetary advantage (table 5). the maximum maize equivalent yield (10.62 t ha -1 ) was obtained from t5 treatment. the results showed that all the intercropping systems gave higher maize equivalent yield than that of their corresponding sole crop yield. the lowest maize equivalent yield (6.48 t ha -1 ) was obtained from no weeding regime of sole maize. akhteruzzaman and quayyum (1991) and patra et al. (2000) also reported similar observations in different intercropping systems. land equivalent ratio varied from 1.07 to 1.81 in intercropping systems with different hand weeding treatments (table 6). the highest land equivalent ratio (ler) was 1.81 in maize + mungbean with two hand weedings situation and the lowest (1.07) was in maize + blackgram intercropping with no weeding situation. the results showed that the total gross return was higher in all the intercropping systems compared to their respective sole crop. higher total gross return of tk. 108853 ha -1 was obtained from maize + mungbean intercropping with two hand weedings situation. on the other hand, the lowest gross return of tk. 50643 ha -1 from sole situation in mungbean treatment (table 6). the cost of cultivation increased in the intercropping systems compared with the respective sole crop of maize and legumes. it might be due to increased seed requirement and additional cultural practices for legumes in the intercropping systems. the results support those of patel and rajagopal (2001) under cereal + legume intercropping system. the highest cost of cultivation was observed in maize + soybean (tk. 45035 ha -1 ) intercropping systems. the lowest cost of cultivation was tk. 30515 ha -1 from sole situation of mungbean. the cost of cultivation increased in the intercropping system over the respective sole crops of legumes due to another crop addition in this system. table 5. equivalent yield and land equivalent ratio of maize + legume intercropping systems at different weeding regime during the kharif season of 2012 treatments maize equivalent yield (t ha-1) land equivalent ratio t1 6.48 1.00 t2 6.80 1.14 t3 8.37 1.42 t4 8.41 1.60 t5 10.62 1.81 t6 6.98 1.11 t7 7.54 1.20 t8 8.37 1.34 t9 9.27 1.48 t10 6.86 1.07 t11 8.75 1.34 t12 9.22 1.43 t13 8.62 1.51 t14 8.05 1.00 t15 1.00 t16 1.00 t17 1.00 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free) , t15=sole mungbean (weed free) , t16=sole soybean (weed free) and t17= sole blackgram (weed free) 10 naher et al. table 6. cost benefit analysis of different maize + legume intercropping systems during the kharif season of 2012 treatments gross return (tk. ha-1) cost of cultivation (tk. ha-1) net return (tk. ha-1) bcr maize legume total t1 66388 66388 40515 25873 1.64 t2 51472 19161 70633 41715 28918 1.69 t3 58067 28298 86365 43215 43150 2.00 t4 66755 29918 96673 43215 53458 2.24 t5 73430 35423 108853 44000 64853 2.47 t6 51325 22791 74115 40034 34081 1.85 t7 52953 27121 80074 42535 37539 1.88 t8 58295 30415 88710 42535 46175 2.09 t9 64042 34081 98123 45035 53088 2.18 t10 51005 19921 70926 41115 29811 1.73 t11 60475 29611 90086 42615 47471 2.11 t12 64613 30176 94789 42615 52174 2.22 t13 67092 31698 98790 43015 55775 2.30 t14 82308 82308 44675 37633 1.84 t15 50643 50643 30515 20128 1.66 t16 65669 65669 32785 32884 2.00 t17 64322 64322 30555 33767 2.11 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram (weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free) , t15=sole mungbean (weed free) , t16=sole soybean (weed free) and t17= sole blackgram (weed free) market price: mungbean tk. 30 kg -1 ; blackgram tk. 15 kg -1 ; soybean tk. 15 kg -1 and maize tk. 12 kg -1 . the higher bcr (benefit cost ratio) was observed from same treatment of the maize + mungbean with two hand weedings situation (2.47) but sole legumes gave also higher bcr than other situations except mungbean (1.66). sole maize with no weeding treatment gave lower bcr than other intercropping systems (1.64). conclusion the results of this study revealed that intercropping of two rows of mungbean in between two rows of maize with two hand weeding at 20 and 40 dae to be a profitable practice for good yield advantages, optimum exploitation of the environmental resources, weed control efficiencies, ler and monetary values. references akhteruzzaman, m. and m.a. quayyum. 1991. intercropping of maize with three varieties of groundnut at two levels of plant population. bangladesh j. agril. sci. 18(1): 39-44. banddyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum legume intercropping systems. ph. d. dissertation, indian agril. res. insti. new delhi. production potential and weed dynamics in maize 11 baumann d.t., m.j. kropf and l. bastiaans. 2000. intercropping leeks to suppress weeds. weed res. 40: 361-376. cruz, f.d., k. moody and m.b.d. ramas. 1986. reducing variability sampling weeds in upland rice (oryza sativa). philopp j. weed sci. 13: 56-59. dwivedi, s.k. and g.k. shrivastava. 2011. planting geometry and weed management for maize (zea mays) – blackgram (vigna mungo) intercropping system under rainfed vertisols. indian j. agron. 56(3): 202-208. getachew, a., g. amare and w. sinebo. 2007. cereal-faba bean mixed cropping: yield advantage and land use ei ciency. res. rep. 70. ethopian inst. agric. res., addis ababa, ethiopia. katsaruware, r.d. and i.o. manyanhaire. 2009. maize-cowpea intercropping and weed suppression in leaf stripped and detasselled maize in zimbabwe. j. environ. agric. food chemis. 8(1): 1218-1226. khan, m.a., a.n. khan, r. khan, umm-e-kalsoom and m.a. khan. 2011. weed control efficiency of intercropping legumes in maize. pak. j. weed sci. res. 17(4): 303-312. kumar, a. and k.s. thakur. 2005. influence of intercropping and weed control measures on weeds and productivity of rainfed maize (zea mays). ind. j. weed sci. 37: 65-67. mundra, s.l., a.k. vyas and p.l. maliwal. 2003. effect of weed and nutrient management on weed growth and productivity of maize (zea mays l.). indian j. weed sci. 35(1&2): 57-61. odedina, j.n, t.o, fabunmi, s.o. adigbo, s.a. odedina and r.o. kolawole. 2014. evaluation of cowpea varieties (vigna unguiculata l. walp) for intercropping with okra (abelmoschus esculenta, l moench). j. res. com. 2(2): 91-108. pandey, a.k. and v. prakash. 2002. weed management in maize and soybean intercropping system. indian j. weed sci. 34(1&2): 58−62. patel, j.r. and rajagopal, s. 2001. production potential of forage maize (zea mays l.) with legumes under intercropping systems. indian j. agron. 46(2): 211-215. patel, v.j., p.n. upadhyay, j.b. patel and m.i. meisuriya. 2006. effect of herbicide mixture on weeds in kharif maize (zea mays l.) under middle gujarat conditions. indian j. weed sci. 38(1&2): 54-57. patra, b.c., b.k. mandal and a.l. padhi. 2000. production potential of winter maize (zea mays l.) based intercropping systems. indian j. agril. sci. 70(4): 203-206. quayyum, m.a. and a.f.m. maniruzzaman. 1995. effect of maize (zea mays l.) and rice (oryza sativa) with blackgram (phaseolus mungo). indian j. agron. 40(1): 20-25. razzaque, m.a., s. rafiquzzaman, m.m. bazzaz, m.a. ali and m.m.r. talukdar. 2007. study on the intercropping groundnut with chill at different plant populations. bangladesh j. agril. res. 32(1): 37-43. seran, t.h. and i. brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135-145. torofder, g.s., a. ahmed, m.m. alam and m.a. quayyum. 1992. intercropping of maize with different legume. bangladesh j. life sci. 4(2): 33-37. uddin, m.s., m.j. rahman, s.a. begum and m.r. ali. 2003. intercropping of maize with soybean in saline area under rainfed condition. bangladesh j. agril. res. 28(3): 451-455. undie, u.l., d.f. uwah and e.e. attoe. 2012. effect of intercropping and crop arrangement on yield and productivity of late season maize/soybean mixtures in the humid environment of south southern nigeria. j. agril. sci. 4(4): 37-50. willey, r.w. 1979. intercropping: its importance and research needs. field crops abs. 32(1): 1-10. willey, r.w. and m.r. rao. 1980. a competitive ratio for quantifying competition between intercrops. expl. agric. 16: 117-125. wortmann, c.s., m. mamo, c. mburu, e. letayo, g. abebe, k.c. kayuki, m. chisi, m. mativavarira, s. xerinda, and t. ndacyayisenga. 2009. atlas of sorghum (sorghum bicolor (l.) moench) production in eastern and south-ern africa. univ. of nebraska-lincoln, lincoln. microsoft word 7. baj-293_revised bangladesh agron. j. 2018, 21(1): 71-76 effect of irrigation and mulch materials on growth and yield of wheat s. rummana1, a.k.m.r. amin1*, m.s. islam and g. m. faruk2 1department of agronomy, sher-e-bangla agricultural university 2deputy secretary, ministry of health and family welfare *corresponding author, e-mail: ruhulsau@yahoo.com (received: 14 december 2017, accepted: 01 october 2018) keywords: wheat, irrigation, mulch, straw, rice husk, plastic sheet, yield abstract an experiment was carried out in agronomy field of sher-e-bangla agricultural university, dhaka to find out the performance of wheat (var. bari gom 27) as influenced by time of irrigation and different mulch materials during 2015-2016. four levels of irrigation viz. control, one irrigation at cri (crown root initiation) stage, one irrigation at flowering stage and two irrigations each at cri + flowering stage; and four different mulch materials viz. control, rice straw, rice husk and plastic sheets were considered as treatment variables. the experiment was laid out in a splitplot design with three replications, assigning irrigation to main plot and mulch materials to sub plots. results showed that time of irrigation and different mulch materials had significant effect on plant characters, yield and yield components of wheat. two irrigations given at cri + flowering stage resulted with significantly higher plant height, number of spikelets spike-1, number of grains spike-1, 1000grain weight, grain yield, straw yield and harvest index over one irrigation and control plots. among mulch materials, black plastic mulch resulted with significantly higher grain yield of wheat. the highest grains (4.15 t ha-1) and straw yields (4.25 t ha-1) were obtained with two irrigations at cri and flowering stage with black plastic mulch for achieving higher productivity. introduction wheat (triticum aestivum l.) is the second largest cereal crop next to rice in bangladesh. during the year 2014-2015, 1347926 m. tons of wheat was produced from 436814 hectares of land with an average yield of 3.1 t ha-1 in the country (bbs, 2015). the months of december and january are almost dry where; july receives maximum precipitation of 12.85% (bbs, 2015). the residual soil moisture following the rainy season is abundantly available at early stage of the crop, but not usually retained in the later stage. so water is the most important limiting factor for wheat production. more than 80% of the water resources from surface runoff and groundwater have been used for irrigation. the excessive exploitation of groundwater resources from shallow and deep aquifers has caused the water table to fall and create many other environmental problems (liu and wei, 1989). the groundwater table is falling steadily at the rate of about 1 m per year and the main factors leading to this fall are the expanding wheat area which is irrigated with groundwater and the low water-use efficiency of crops (hu et al., 2002). the availability of water for irrigated wheat (water requirement of high yielding variety normally varies from 400 and 500 mm) is also gradually becoming limited. mulching has been proved to be beneficial in conserving moisture and increasing productivity of wheat (chakraborty et al., 2008). mulching is an important agronomic practice to reduce moisture loss from soil surface. mulching is a traditional practice in agriculture which acts as a barrier to evaporation, soil temperature could be raised or reduced depending on growing season and crop 72 rummana et al. requirement, higher yield and quality, less infestation of insect and disease, prolonged growing season, higher nutritive value of the produce, improved storage ability etc. transfer of vapor or heat from the soil. mulching is done with crop residues, polythene paper, ordinary paper, gravel, concrete etc. the most well known benefits of mulching are soil moisture and temperature regulation, suppressing weeds, improving germination and emergence of seedlings. plastic sheets and rice husk are also effective mulch material. however, very few studies were carried out in bangladesh regarding the effect of irrigation and mulching in wheat. therefore, this study is designed to understand the interactive effect of variable irrigation levels and different mulch materials on growth and productivity of wheat. materials and methods the experiment was conducted at the agronomy field and laboratory, sher-e-bangla agricultural university, dhaka-1207 during the period from november, 2015 to march, 2016. before sowing, wheat var. bari gom 27 seeds were tested for germination (over 90%). the experiment was set up in november in a splitplot design where accommodate irrigation treatments viz .control (i0), one irrigation at cri stage (i1), one irrigation at flowering stage (i2) and two irrigations each at cri + flowering stage (i3) in main plot and and mulch materials (control, rice straw, rice husk, and black plastic sheets) in sub-plot. the size of each unit plot was 4.0 m x 2.5 m with row to row distance was 50 cm. the land was fertilized with cow dung – urea – tsp – mop gypsum @ 10000-220-180-40-110 kg ha-1, respectively. cow dung was applied 10 days before final land preparation. total amount of triple superphosphate, muriate of potash, gypsum and half of urea were applied at basal doses during final land preparation. the remaining 50% urea was side dressed at 35 days after sowing (das). flood irrigation applied with plastic pipe in individual plots as per treatment. mulch materials were applied in the plots as per treatment after completion of germination. for mulching, upper surface of soil of respective plot (as per treatment) was covered with the mulch materials. data on grain yield and yield components were recorded. grain yield was adjusted at 14% moisture content. the data was analyzed using a computer operated program stat 10. results and discussion effect of irrigation on plant height and yield component plant height and yield components differed significantly due to different levels of irrigation (table 1). at harvest the tallest plant (76.02 cm) was obtained with two irrigations at cri + flowering stage and the shortest plant from i0 (control). spikelet spike-1 was influenced by different irrigation level (table 1). the highest (45.00) number of spikelet was found with two irrigation at cri + flowering stage. one irrigation at cri and at flowering resulted with similar spikelet spike-1. lowest number of spikelets (39.31) was found with control treatment. this result was in agreement with the findings of ali and amin (2007).two irrigations at cri + flowering (i3) reflected the highest ( 49.71) number of grains spike-1. one irrigation at flowering (i2) and control (i0) appeared with the lowest numbers (44.64 and 43.59, respectively) of grains spike-1. mushtaq and muhammad (2005) reported that the increased frequency of irrigation improved the number of grains spike-1. moreover, thousand grain weight was significantly influenced by different level of irrigations (table 1). two irrigations at cri + flowering facilitated to produced the grains of maximum weight value (45.96 g) followed by i1 (one irrigation at cri) 41.51 g and i2 (40.04 g) (one irrigation at flowering). the lowest thousand grain weight (38.28 g) was obtained from i0 (control) which were comparable with those of kong et al. (2008) and mushtaq and muhammad (2005). grain and straw yield effect of irrigation and mulch materials on growth 73 irrigation levels showed significant variation in grain yield of wheat (table 1). the highest grain yield (3.37 t ha-1) was recorded from two irrigations at cri and flowering of plants. among the treatments, the control plots appeared with lowest grain yield (1.72 t ha-1). straw yield was also affected due to irrigation treatments. two irrigations (i3) facilitated better growth of rice straw resulting the highest yield (3.98 t ha-1) compare to the other irrigation levels including control treatments (table 2). irrigation number and timing also have better effects on plant growth and yield of rice as revealed in this study is also supported by chaudhary and dahatonde (2007). table 1. effect of irrigation on plant height, yield and yield attributes of wheat treatment plant height at harvest (cm) spikelets spike-1 (no.) grain spike-1 (no.) 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) i0 63.41 39.31 43.59 38.28 1.72 2.26 i1 73.22 43.03 46.91 41.51 3.07 3.44 i2 67.17 42.64 44.64 40.04 2.57 3.11 i3 76.02 45.00 49.71 45.96 3.73 3.98 lsd (0.05 ) 1.04 1.81 1.45 0.64 0.02 0.02 cv (%) 1.49 4.26 3.14 1.54 0.80 0.58 here, i0= control i1= one irrigation at cri i2= one irrigation at flowering i3= two irrigations at cri + flowering effect of mulching on plant height and yield components at harvest the tallest plant (74.20cm) was obtained with black plastic mulch and the shortest plant (66.05 cm) from i0 (control). number of spikelet spike-1 differed significantly with different mulch materials (table 2). highest number of spikelet was obtained from black plastic mulch (44.76) which was statistically similar with rice straw mulch (43.80). lowest spikelet number spike-1 was obtained from control (39.72). highest number of grains (49.41) were obtained from m3 (black plastic sheet), followed by m1 (rice straw). rice husk (m2) and control (m0) plots were recorded with statistically similar results (45.11 and 43.4, respectively) with control being the lowest. the result revealed that black plastic mulch appeared with calculated 5.33, 9.53 and 13.82% higher grains spike-1 than (m1, m2 and m0 mulches, respectively. one thousand grain weight significantly differed due to different mulch materials (table 2). significantly the maximum 1000-grain weight (43.59 g) was obtained from m3 (black plastic sheet mulch).followed by rice straw (m1) mulch (42.15 g). no mulch treatment (control) showed the lowest weight (39.48 g). grain and straw yield grain yield ha-1 differed with different mulch materials (table 2). significantly the maximum grain yield was obtained from black plastic mulch (3.34 t ha-1) followed by rice straw (2.94 t ha1) mulch. the use of black plastic sheet as a mulch might have enhanced nutrients uptake due to favorable soil moisture which ultimately increased grain yield of wheat as also supported by li et al. (2004), deng et al. (2006) and ramakrishna et al. (2006). straw yield differed significantly due to different mulch materials (table 4). highest straw yield (3.67 t ha-1) was obtained from m3 (black plastic sheet mulch) followed by. rice straw mulch treatment (m1). no mulch plot showed the lowest (2.77 t ha-1) straw yield. deng et al., (2006) and ramakrishna et al., (2006) also reported similar advantages of mulching in straw yield of wheat. table 2. effect of mulching on plant height, yield and yield attributes of wheat 74 rummana et al. treatment plant height at harvest (cm) spikelets spike-1 (no.) grain spike-1 (no.) 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) m0 66.05 39.72 43.41 39.48 2.27 2.77 m1 71.68 43.80 46.91 42.15 2.94 3.36 m2 67.88 41.70 45.11 40.56 2.54 2.99 m3 74.20 44.76 49.41 43.59 3.34 3.67 lsd (0.05) 1.44 1.44 1.71 0.79 0.04 0.03 cv (%) 2.44 4.03 4.38 2.27 0.95 0.48 here, m0= control m1= rice straw m2= rice husk m3= black plastic sheet interaction effects on plant height and yield components plant height was significantly influenced by interaction effect of irrigation and mulching. the maximum plant height (80.20 cm) was obtained with i3m3 which was statistically similar to i3m1 (two irrigations at cri + flowering and rice straw mulch). the shortest plant (59.47 cm) was obtained from i0m0. different combination of irrigation levels and mulch materials showed significant variation in the number of spikelet spike-1 (table 3). the combination i3m3appeared with the maximum number of spikelets spike-1 (47.18), followed by i3m1, i1m3), i2m3 and i1m.1, respectively. control treatment (i0m0) showed the lowest number (37.17) of spikelets spike-1. highest number of grains spike-1 (52.53) was obtained from i3m3 combination which was statistically similar to i3m1 (50.61)and i1m3 (50.90) combinations. lowest grain spike-1 was obtained from i0m0 (41.27) which was statistically similar to i0m1 (44.53) and i0m2 (42.08). in the case of 1000grain weight i3m3 showed with the maximum weight (47.53 g) and that was statistically similar to i3m1 (46.27), i3m2 (46.01) and i1m1 (46.17 g). the lowest weight of 1000grains (37.11 g) were obtained from i0m0 (control) which was statistically similar to i0m1(37.83 g), i0m2 (38.34 g), i1m2 (38.38 g), i2m0 (38.17 g) and i2m1 (38.34 g). yield different combination of irrigation levels and mulch materials showed significant variation in grain yield ha-1 (table 3). the i3m3 combination (2 irrigations at cri + flowering and black plastic sheet) expressed with the highest grain yield (4.15 t ha-1) which was significantly different from other treatment combinations. second highest grain yield (3.98 t ha-1) was obtained from i3m1 combination. these results revealed that the soil moisture was most efficiently utilized under black plastic mulch. on the other hand the lowest grain yield (1.41 t ha-1) was obtained from i0m0 (control). combined effect of irrigation and mulching showed significant effect on straw yield (table 3). among the combinations, the highest straw yield (4.25 t ha-1) was obtained from i3m3 combination. lowest straw yield (1.98 t ha-1) was obtained from i0m0 (control). table 3. interaction effect of irrigation and mulching on plant height, yield and yield attributes of wheat interaction plant height at harvest (cm) spikelets spike-1 (no.) grain spike-1 (no.) 1000grain weight (g) grain yield (t ha-1) straw yield (t ha-1) i0m0 59.47 37.17 41.27 37.11 1.41 1.98 i0m1 65.50 40.13 44.53 37.83 1.88 2.47 i0m2 61.47 38.57 42.08 38.34 1.62 2.10 i0m3 67.20 41.35 46.47 39.85 1.97 2.51 i1m0 69.40 39.93 43.65 38.64 2.29 2.85 effect of irrigation and mulch materials on growth 75 i1m1 75.53 44.50 47.53 46.17 3.35 3.59 i1m2 70.40 42.37 45.55 38.38 2.74 3.16 i1m3 77.53 45.32 50.90 42.87 3.91 4.14 i2m0 63.27 39.63 41.38 38.17 2.03 2.63 i2m1 68.13 43.87 44.98 38.34 2.56 3.18 i2m2 65.40 41.87 44.45 39.52 2.36 2.85 i2m3 71.88 45.18 47.73 44.12 3.32 3.77 i3m0 72.07 42.13 47.33 44.01 3.35 3.61 i3m1 77.53 46.68 50.61 46.27 3.98 4.20 i3m2 74.27 44.01 48.35 46.01 3.44 3.85 i3m3 80.20 47.18 52.53 47.53 4.15 4.25 lsd (0.05) 2.87 2.88 3.41 1.58 0.04 0.03 cv (%) 2.44 4.03 4.38 2.27 0.95 0.48 here, i0 = control, i1 = one irrigation at cri, i2 = one irrigation at flowering, i3 = two irrigations at cri + flowering, m0 = control, m1 = rice straw, m2 = rice husk, m3 = black plastic sheet. conclusion based on the results of the study it can be concluded that two irrigations at cri and flowering stage in combination with black plastic mulch is the best for obtaining higher yield of wheat. references ali, m.a. and s. amin. 2007. effect of irrigation frequency on yield and yield attributes of wheat cultiver ‘shatabdi’. pak. j. agril. sci. 2(3): 145-147. bbs (bangladesh bureau of statistics). 2015. statistical pocket book of bangladesh. bangladesh bureau of statistics, statistics division, ministry of planning, government of the people’s republic of bangladesh. chakraborty, d., s. nagarajan, p. aggarwal, v. k.gupta, r. k. tomar,r. n. garg, r. n. sahoo, a. sarkar, u. k. chopra, k. s. s. sarma, and n. kalra. 2008. effect of mulching on soil and plant water status, and the growth and yield of wheat (triticum aestivum l.) in a semi-arid environment. agric. water manage. 95: 1323–1334. chaudhary, a.a. and b.n. dahatonde. 2007. influence of irrigation frequency, irrigation depth and antitranspirants on the growth, yield and water use efficiency of wheat. madras agric. j. 24(1):54-55. deng, x. p.,l. shan, h. p. zhang and n. c. turner. 2006. improving agricultural water use efficiency in arid and semiarid areas of china. agric. water manage. 80(13): 2340. doi: 10.1016/j.agwat.2005.07.021. [cross ref]. hu, c.s., x. y. zhang, y. s. chengand, d. pei. 2002. an analysis on dynamics of water table and overdraft in the piedmont of mt. taihang. syst. sci. compr. stud. agric.18 (2): 89–91. kong, x. x., z.p. yanva. and w. j. cheng. 2008. effect of limited irrigation on yield of winter wheat and water use efficiency. plant soil.284: 335-350. li, f.m., j. wang, j. z.xu. and h. l. xu. 2004. productivity and soil to plastic film mulching durations for spring wheat on entisols in the semiarid loess plateau of china. soil till res.78: 9–20. liu, c. and z. wei. 1989. agricultural hydrology and water resources in the north china plain. chinese scientific press, beijing, pp.236. 76 rummana et al. mushtaq, a. and s. muhammad. 2005. growth and yield of wheat is influenced by different irrigation frequencies. faisalabad. pakistan: directorate of agricultural information, ayub agricultural research institute. pak. j. agric. res.43(4): 331-338. ramakrishna, a., h. m. tam, s. p. wani. and t. d. long. 2006. effect of mulch on soil temperature, moisture, weed infestation and yield of groundnut in northern vietnam. field crops res. 95(2-3):115–125. bangladesh agron. j. 2020, 23(2): 13-22 sowing time and management effects on phenology, growth and yield of garden pea s.s. kakon * , m.m. sheikh 1 , m.s.a. khan 2 , a.a.begum * , j.a. chowdhury * and m.a.hossain 3 * agronomy division, bangladesh agricultural research institute, joydebpur,gazipur 1 regional agricultural research station, bari, burirhat,rangpur 2 training and communication wing, bari, gazipur 3 on-farm research division, bari, gazipur, 1701, bangladesh corresponding e-mail: kakonbari@gmail.com (received: 09 september, 2020, accepted: 13 october, 2020) key words: temperature, phenology, sowing date, management practices, yield, garden pea abstract the experiment was conducted at the research field of the agronomy division, bangladesh agricultural research institute (bari), gazipur and regional agricultural research stations (rars), burirhat during two successive rabi seasons of 2015 and 17 to find out the relation between different development events of garden pea (pisum sativum l.) and the sowing time based temperature, and also to minimize the yield reduction by adopting appropriate management practices. the treatments comprised with three sowing dates (30 november, 15 december and 30 december) and three management practices (low, medium and high). under high management, nov. 30 sowing took maximum days (64 days in 2015-16 and 58 days in 2016-17 at joydebpur and 58 days in 2015-16 and 57 days in 2016-17 at rars, burirhat) to reach harvesting maturity. the results indicated that the number of days required for attaining different phenological stages decreased with delay of sowing. late sowing took minimum time from flowering to fresh pod maturity (51 days and 49 days in two years at joydebpur, and 49 days and 46 days in two years at burirhat) due to increase in minimum temperature. the results revealed that the highest pod yield (14.77 t ha -1 in 2015-16 and 13.09 t ha -1 in 2016-17 at joydebpur and 9.63 tha -1 in 2015-16 and 10.33 t ha -1 in 2016-17 at burirhat) was recorded from 30 november sowing with high management practices which was followed by 15 december with the same management. yield reduction in late sowing was reduced to some extent by high management practices. the two year results revealed that 30 november sowing with high management practices (extra 20% recommended fertilizer dose, hrc + two irrigation at pre flowering and pod development stage + seed treatment + one weeding at 21 dae) showed better pod yield than other combinations. introduction pea (pisum sativum l.) is commonly used in human diet throughout the world and it is rich in protein (21-25 %), carbohydrates, vitamin a and c, ca, phosphorous and has high levels of amino acids lysin and trytophan (bhat et al., 2013). average green pod yield per unit area of the crop in the country is quite low as compared to some other countries. the garden pea is grown mainly for young pod to get tender green seeds as vegetable. the crop has gained popularity for its short durability and high nutritive value. besides this, a huge amount of garden pea is consumed as soup. garden pea can play an important role to overcome our national protein deficit. its demand especially to the urban people is increasing day by day. edible-pod peas prefer consistently cool growing conditions rather than hotter areas (slinkard et al., 1994). among the climatic factors, temperature plays a key role in determining sowing time and consequently the duration of different phenophases and thus the crop productivity (tewari and singh, 1993). further, 14 kakon et al. delay in sowing may not permit proper vegetative growth of the crop and it may face high temperature at its later growth stages leading to forced maturity and low productivity. garden pea is a cool loving crop and winter is becoming shorter due to climate change, consequently the crop may be affected. it is mostly grown after aman rice in rice based cropping pattern. temperature above 30 o c is harmful for garden pea (sousa-majer et al., 2004). global temperature is rising. developing seeds exposed to high temperature was found aborted and reduction in pea seed yield (jeuffroy, 1990). high-temperature stress affects reproductive development, as reported in legumes such as chickpea (kaushal et al., 2013; kumar et al., 2013) and pea (guilioni et al., 1997). it was reported that different environmental conditions, especially temperature due to different sowing time provide variable in crop growth, development and yield stability (ali et al., 2016). it is also needed to minimize the yield reduction by taking different management. so, the experiment was conducted to evaluate the crop growth and yield performance under different management practices. materials and methods the experiment was conducted at the research field of the agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur and rars, burirhat during rabi season of 2015-16 and 2016-17.the soil was silty clay in texture with ph of 6.5. the crops received no rainfall at joydebpur, gazipur and rars, burirhat during the crop season of 2015-16 and 2016-17. the treatments were comprised with three sowing dates; i. 30 november (d1), ii. 15 december (d2) and iii. 30 december (d3) and management practices; i. low: 25-30-56-5 kg npks/ha, no irrigation, no weeding, no pesticide (m1). ii. medium: 25-30-56-5 kg npksha -1 , one weeding at 21 dae, two irrigations at pre flowering and pod development stages and spraying pesticides (dithane m-45) (m2). iii. high: 30-36-67-6 npks kgha -1 (recommended dose + extra 20% recommended dose, hrc+ two irrigation at pre flowering and pod development stage, seed treatment(seeds were treated with vitavex200 @ 2.5 g kg -1 seeds before 24 hours of sowing),one weeding at 21 dae (m3). the experiment was laid out in a split-plot design with three replications. the sowing dates were assigned in the main plots and management practices were arranged in sub-plots. garden pea var. bari motorshuti-3 was used as test crop. seeds were sown in lines with maintaining 30 cm row to row spacing. half of urea and full doses of other fertilizers were applied at the time of final land preparation. the remaining half of urea was top dressed at flowering stage followed by irrigation. in case of low management, all fertilizers were applied at the time of final land preparation. insecticide was sprayed in the respective treatment plots. at flowering stage, plant samples were collected from an area of one square meter of all treatments and the plant samples were dried in an oven for 72 hours at 80 o c and then dry weights were recorded. the phenological data were recorded by field monitoring every day. the yield component data was collected from 10 randomly selected plants prior to harvest from each plot. meteorological data for air temperature and rainfall were obtained from meteorological station located adjacent to the experiment field. at later stage of cropping season rust disease was visible. rust disease was controlled by tilt only joydebpur. at harvest, the yield data was recorded plot wise and analyzed statistically by mstat-c and means were compared using least significant difference (lsd). results and discussion days for development events the phenological stages of garden pea may be broadly classified as emergence, flowering, 50% flowering, pod set and fresh pod. the number of days required for different development events of garden pea grown under different sowing dates and management practices over the years and over the locations have been presented in table 1. all the phonological events varied on sowing dates and management practices. emergence of early sown crop occurred 1 days earlier than those of late sown. late sowing reduced the length of vegetative growth stage causing early flowering. the 30 november https://www.frontiersin.org/articles/10.3389/fpls.2017.01658/full#b167 https://www.frontiersin.org/articles/10.3389/fpls.2017.01658/full#b191 https://www.frontiersin.org/articles/10.3389/fpls.2017.01658/full#b109 sowing time and management effects on phenology, growth and yield 15 sowing took maximum days for first flowering (32 days and 29 days in both the years at joydebpur and 31 days for two years at burirhat) and 50% flowering (35 days for two locations in 2015-16 and 31 days in 2016-17 at joydebpur and 34 days in 2016-17 at burirhat) whereas 30 december sowing took minimum days for first flowering (26 days in 2015-16 and 28 days in 2016-17 at joydebpur and 28 days in 2015-16 and 26 days in 2016-17 at burirhat) and 50% flowering (29 days in two years over the locations).the days for harvesting maturity (fresh pod ) varied by sowing date and management practices. table 1. number of days required for attaining different developmental events of garden pea grown at different sowing dates under different management practices during rabi season of 2015-16 and 2016-17 at joydebpur and rars, burirhat treatments developmental events sowing dates management emergence days to1st flower initiation 2015-16 2016-17 2015-16 2016-17 joy. bur. joy. bur. joy. bur. joy. bur. 30 nov. low 6 7 6 7 32 31 29 31 medium 6 6 6 7 32 31 29 30 high 6 7 6 7 32 30 29 28 15 dec. low 6 7 6 8 27 28 29 27 medium 6 7 6 7 27 28 29 27 high 6 6 6 7 27 27 29 26 30 dec. low 7 8 8 8 26 27 28 26 medium 7 8 8 8 26 27 28 26 high 7 7 8 7 26 27 28 25 table 1. cont , d treatments developmental events sowing dates management days to 50% flower initiation fresh pod 2015-16 2016-17 2015-16 2016-17 joy. bur. joy. bur. joy. bur. joy. bur. 30 nov. low 35 35 31 34 62 58 56 55 medium 35 34 31 33 64 60 58 57 high 35 34 31 32 64 61 58 57 1 15 15 dec. low 29 31 31 30 56 53 52 50 medium 29 31 31 30 57 54 54 52 high 29 30 31 30 57 55 55 52 30 dec. low 29 29 29 29 51 49 49 46 medium 29 29 29 28 55 52 51 48 high 29 29 29 27 55 53 51 48 the 30 november sowing took maximum days (64 days in 2015-16 and 58 days in 2016-17 at joydebpur and 58 days in 2015-16 and 57 days in 2016-17at burirhat). low management practices took minimum days for harvesting fresh pod and both the medium and high management practices took maximum days. the minimum days for harvesting maturity were found in 30 december sowing (51 days and 49 days in two years at joydebpur 49 days and 46 days in two years at burirhat) at low management practices. the maximum days needed for pod harvest (64 days in 2015-16 and 58 days in 2016-17) was recorded both medium and high management practices at 30 nov. sowing. the reasons for variation in growth duration might be due to variation in day and night temperature and in increased temperature at the later sowing. the mean temperatures during crop duration varied across the sowing dates over the years and over the locations (table 2a and 2b).the late sown crop received comparatively higher temperatures from emergence to 1 st flowering and 50% flowering to maturity stages than those of early sown ones. at 30 16 kakon et al. dec. sowing, from emergence to 1 st flowering the maximum and minimum temperature were (27 0 c and 19.60 0 c in 2015-16 and 31.35 0 c and 12.60 0 c in 2016-17), respectively at joydebpur. from 50% flowering to harvesting maturity the maximum and minimum temperature were (29.65 0 c and 11.99 0 c in 2015-16 and 30.24 0 c and 14.72 0 c in 2016-17), respectively at joydebpur. at 30 dec. sowing, from emergence to 1 st flowering the maximum and minimum temperature were (28.67 0 c and 16.00 0 c in 2015-16 and 28.70 0 c and 16.80 0 c in 2016-17), respectively. from 50% flowering to harvesting maturity the maximum and minimum temperature were (22.43 0 c and 11.43 0 c in 2015-16 and 25.83 0 c and 12.06 0 c in 2016-17), respectively at burirhat. late sown crop produced flower early and also matured early than early sown due to prevailing higher minimum and maximum temperatures. similar results were also observed by helena and brodaczewska (2007). table 2a. average mean temperature for different phonological events of gardenpea (var. bari motorshuti-3) as affected by sowing dates at joydebpur during rabi season of 2015-16 phenological events sowing dates 30 november 15 december 30 december min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c emergence (days 18.35 29.02 17.50 24.00 15.40 26.80 emergence to1st flowering 16.30 27.40 18.00 24.00 19.60 27.00 first flowering to 50% flowering 12.40 26.70 16.23 26.03 10.93 26.15 50% flowering to harvesting maturity(fresh pod) 11.93 24.73 12.38 25.68 11.99 29.65 table 2a. average mean temperature for different phenological events of gardenpea (var. bari motorshuti-3) as affected by sowing dates at joydebpur during rabi season of 2016-17 phenological events (days) sowing dates 30 november 15 december 30 december min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c emergence 16.73 30.67 14.83 27.38 12.43 27.48 emergence to1st flowering 14.74 28.16 13.15 26.75 12.42 27.45 first flowering to 50% flowering 13.00 28.06 11.33 27.46 12.60 31.35 50% flowering to harvesting (fresh pod) 11.56 26.43 13.36 28.11 14.72 30.24 table 2b. average mean temperature for different phonological events of gardenpea (var. bari motorshuti-3) as affected by sowing dates at rars, burirhat during rabi season of 2015-16 phenological events sowing dates 30 november 15 december 30 december min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c emergence (days 17.80 28.73 17.80 28.73 16.23 27.53 emergence to1st flowering 16.00 28.67 16.40 26.07 16.20 25.60 first flowering to 50% flowering 15.90 20.67 13.53 24.93 11.50 23.40 50% flowering to harvesting maturity(fresh 11.43 22.43 12.47 24.33 13.33 26.73 sowing time and management effects on phenology, growth and yield 17 pod) table 2b. average mean temperature for different phonological events of gardenpea (var. bari motorshuti-3) as affected by sowing dates at rars, burirhat during rabi season of 2016-17 phenological events (days) sowing dates 30 november 15 december 30 december min. tem. 0c max. tem. 0c min. tem. 0c max. tem. 0c 73 max. tem. 0c emergence 17.00 28.70 16.87 28.70 16.43 28.60 emergence to1st flowering 16.80 28.70 16.40 28.33 15.47 28.00 first flowering to 50% flowering 12.13 25.33 11.60 24.00 13.90 27.77 50% flowering to harvesting (fresh pod) 12.06 25.83 12.76 26.47 14.17 27.86 total dry matter at, flowering stage, the total dry matter production of garden pea varied due to different sowing dates and management practices (fig.1a and 1b) over the years over the locations. at joydebpur, significantly the highest total dry matter (46.5gm -2 in 2015-16 and 41.93 gm -2 in2016-17) was recorded in 30 november sowing with high management practices. the lowest total dry matter (14.68 g m -2 in 2015-16 and20.79 g m -2 in 2016-17 and) was recorded at 30 december sowing with low management practices which was identical with medium management practices at the same date of sowing. on the other hand, at burirhat, the highest total dry matter (40.20 gm -2 in 2015-16 and 42.67gm -2 in 2016-17) was recorded in 30 november sowing with high management practices. the lowest total dry matter (14.86 g m -2 in 2015-16 and 16.34 g m -2 in 2016-17) was recorded in 30 december sowing with low management practices which was identical with medium management practices at the same date of sowing. 0 10 20 30 40 50 60 d1m1 d1m2 d1m 3 d2m 1 d2m 2 d2m 3 d3m 1 d3m 2 d3m3 t o ta l d ry m a tt e r( g m -2 ) treatment 2015-16 2016-17 18 kakon et al. d1= 30 nov. d2= 15 dec. d3= 30 dec., m1=low management, m2=medium management, m3= high management fig.1a. total dry matter production of gardenpea at flowering stage under different sowing dates and management practices during 2015-16 and 2016-17 at joydebpur. d1= 30 nov. d2= 15 dec. d3= 30 dec., m1=low management, m2=medium management, m3= high management fig. 1b. total dry matter production of gardenpea at flowering stage under different sowing dates and management practices during 2015-16 and 2016-17 at rars, burirhat. yield and yield attributes plant population, plant height, number of pods plant -1 and pod yield were significantly different by different sowing dates and management practices over the location over the years (table 3). maximum population (14 plant m -2 in 2015-16 and 16 plant m -2 in 2016-17) was recorded in 30 december sowing with high management practices and the lowest (13 plant m -2 ) recorded from 30 november sowing with low management practices at joydebpur. on the other hand, maximum population (15.72plant m -2 in 2015-16 and 14.72 plant m -2 in 2016-17) was recorded in 30 november sowing with high management practices at burirhat. the tallest plant was recorded from 30 november sowing with high management practices (48.33 cm and 43.70 cm in two years at joydebpur and 45.20 cm in 2015-16 and 52.00 cm in 2016-17 at burirhat) which was identical with medium management practices at the same date of sowing (47.67 cm in 2016-17 at burirhat). the shortest plant was recorded from 30 december sowing with low management practices (36.78 cm in 2015-16 and 32.83 cm in 2016-17 at joydebpur and 33.13 cm in 2015-16 and 37.16 cm in 2016-17 at burirhat). significantly the highest number of pods (16.67 plant -1 in 2016-16 and 13.45 plant -1 in 2016-17 at joydebpur and 19 plant -1 in 2015-16 and 15.00 plant -1 in 2016-17 at burirhat) was recorded in 30 november sowing with high management practices while lowest number of pod in 30 december sowing with low management practices. pod yield of garden pea varied significantly under different sowing dates and management practices. pod yield of garden pea was more at november 30 sowing and decreased towards late sowing. the maximum pod yield also recorded from 30 november sowing with high management practices (14.77 tha -1 in 2015-16 and 13.09 t ha -1 in 2016-17 at joydebpur and 9.63 t ha -1 in 2015-16 and 10.33 t ha -1 in 2016-17 at burirhat) which was followed by 15 dec. sowing of same management practices. the lowest pod yield was obtained from 30 december sowing with low management practices (8.90 t ha -1 in 0 5 10 15 20 25 30 35 40 45 d1m1 d1m2 d1m 3 d2m 1 d2m 2 d2m 3 d3m 1 d3m 2 d3m3 t o ta l d ry m a tt e r (g m -2 ) treatment 2015-16 2016-17 sowing time and management effects on phenology, growth and yield 19 2015-16 and 8.70 t ha -1 in 2016-17 at joydebpur and 5.58 t ha -1 in 2015-16 and 5.00 t ha -1 in 2016-17 at burirhat). the lower pod yield at 30 december sowing might be due to prevailing high temperature during flowering to maturity (fig. 2a and 2b and fig.3a and 3b) that hastens forced maturity and reduced tdm production and translocation to the yield components. similar results were recorded by ali et al. (2016). fig 2a. maximum and minimum temperature during growing period (2015-2016) at bari, joydebpur, gazipur. fig 2b. maximum and minimum temperature during growing period (2016-2017) at bari, joydebpur, gazipur. 0.00 10.00 20.00 30.00 40.00 50.00 60.00 15-nov 30-nov 15-dec 30-dec 15-jan 30-jan 15-feb 29-feb t e m p e ra tu re ( 0 c ) growing period (2015-16) max min 0 10 20 30 40 50 60 15-nov 30-nov 15-dec 30-dec 15-jan 30-jan 15-feb 28-feb t e m p e ra tu re ( 0 c ) growing period (2016-17) min max 20 kakon et al. fig 3a. weekly mean temperatures (max. and min.) during crop growing period 2015-16 at bari, rars, burirhat. fig 3b. weekly mean temperatures (max. and min.) during crop growing period 2016-17 at bari, rars, burirhat. this study indicated that raise in temperature reduced the grain growth duration resulted in yield reduction, which in agreement with the findings of mohanty et al. (2001). it was observed that the pod yield of dec. 30 sowing was increased from 8.70 to 10.18 t ha -1 through high management practices. it was noted that the crop was partially damaged by rust disease before harvest that resulting poor yield in all treatments at joydebpur. table 3. plant population, plant height and yield contributing characters and yield of garden pea grown at different sowing dates under different management practices at joydebpur and rars, burirhat during rabi season 2015-16 and 2016-2017 treatments plant population m-2 plant height(cm) joydebpur burirhat joydebpur burirhat 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 d1m1 10.69 12.67 13.11 d 11.11 d 44.62 39.16 34.60 cd 38.40 d d1m2 10.55 14.00 14.27 b 13.07 b 46.78 42.00 40.63 b 43.80 bc d1m 3 9.67 14.67 15.72 a 14.12 a 48.33 43.70 45.20 a 52.00 a d2m 1 10.95 14.33 14.46 b 10.56 d 42.03 37.09 33.07 d 37.60 d d2m 2 11.11 15.00 14.32 b 12.62 c 44.02 39.26 36.13 bc 41.80 cd 0 5 10 15 20 25 30 35 t e m p e ra tu re maximum minimum 0 5 10 15 20 25 30 35 t e m p e ra tu re maximum minimum sowing time and management effects on phenology, growth and yield 21 d2m 3 10.11 15.33 15.03 a-c 12.83 bc 45.32 42.25 42.33ab 47.67 ab d3m 1 12.44 15.00 13.44 d 10.44 d 36.78 32.83 33.13 d 37.16 d d3m 2 12.22 15.33 14.56 b 11.56 d 38.17 34.19 35.67 c 38.40 d d3m3 14.00 16.00 15.10 a-c 11.10 d 39.61 36.56 37.67 bc 41.73 cd lsd 1.23 1.72 * * 4.66 0.12 * * cv (%) 6.12 6.61 5.21 3.34 6.69 6.75 5.05 6.51 cont , d treatments pods plant-1(no.) pod yield tha-1 joydebpur burirhat joydebpur burirhat 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 d1m1 12.53 11.91 10.73 d 10.27 d 11.03 10.90 6.86 cd 5.80 e d1m2 15.00 12.87 11.00 bc 12.60 bc 12.47 12.45 8.68 ab 8.44 b d1m 3 16.67 13.45 14.27 a 15.00 a 14.77 13.09 9.63 a 10.33 a d2m 1 10.69 11.55 12.87 bc 11.00 d 10.17 10.17 6.37 cd 6.38 de d2m 2 13.07 12.06 11.80 bc 12.90 c 11.50 12.15 7.41 bc 6.70 de d2m 3 14.20 13.09 14.07 ab 13.20 b 13.63 12.75 9.33 a 9.07 ab d3m 1 7.20 7.18 10.00 d 9.60 d 8.98 8.70 5.58 cd 5.00 f d3m 2 7.57 8.86 10.33 d 11.93 c 10.08 9.58 5.71 cd 6.70 de d3m3 8.78 9.89 11.27 cd 12.00 c 11.50 10.18 5.10 d 7.44 cd lsd(0.05) 1.11 0.50 * * 0.52 0.36 * * cv (%) 5.30 5.95 6.74 9.60 5.54 5.81 3.66 6.32 d1= 30 nov. d2= 15 dec. d3= 30 dec., m1=low management, m2=medium management, m3= high management conclusion the results revealed that temperature variation in different sowing dates influenced highly on phenology, growth and yield of garden pea. increased temperature enhanced early flowering of late sown garden pea. high temperature from flowering to maturity reduced duration of pod setting and produced lower yield at 30 dec. sowing. the pod yield reduction was reduced to some extent by high management practices. two year results revealed that 30 november sowing with high management practices (extra 20% recommended fertilizer dose, hrc + two irrigation at pre flowering and pod development stage + seed treatment + one weeding at 21 dae) showed better pod yield than other combinations. references ali, m.z., m.a. aziz, m.a.i. sarker, s. mazumder, s.k. paul, t.a. mujahidi, m.s.a. khan and m.s. bhuiyan. 2016. effect of sowing time based temperature variations on growth, yield and seed quality of garden pea. bangladesh agron. j. 19(1): 29-36. bhat, t.a., m. gupta, m.a. ganai, r.a. ahanger and h.a. bhat. 2013. yield, soil health and nutrient utilization of field pea (pisum sativum l.) as affected by phosphorus and biofertilizers under subtropical conditions of jammu, intl. j. m. plant anim. sci. 1(1): 1-8. guilioni, l., j. wery and f. tardieu. 1997. heat stress-induced abortion of buds and flowers in pea: is sensitivity linked to organ age or to relations between reproductive organs. ann. bot. 80: 159–168. helena, ł. and a. brodaczewska. 2007. the influence of environmental factors on flowering of french bean (phaseolus vulgaris). acta agrobot. 60(2): 153-159. jeuffroy, m.h., c. duthion, j.m. meynard and a. pigeaire. 1990. effect of a short period of high day temperatures during flowering on the seed number per pod of pea (pisum sativum l). agron. edp sci. 10(2): 139-145. 22 kakon et al. kaushal, n., r. awasthi, k. gupta, p. gaur, k.h. siddique and h. nayyar. 2013. heat-stress-induced reproductive failures in chickpea (cicer arietinum) are associated with impaired sucrose metabolism in leaves and anthers. funct. plant biol. 40: 1334–1349. kumar, s., p. thakur, n. kaushal, j.a. malik, p. gaur and h. nayyar. 2013. effect of varying high temperatures during reproductive growth on reproductive function, oxidative stress and seed yield in chickpea genotypes differing in heat sensitivity. arch. agron. soil sci. 59: 823–843. mohanty, s.k., b. baisakih, u.k. dikshit and b. bhol. 2001. kalamung, a promising local mungbean cultivar. environ. ecol. 16(1): 222-223. slinkard, a.e., g. bascur and g. hernandez-bravo. 1994. biotic and abiotic stresses of cool season food legumes in the western hemisphere. pp.195–203. sousa-majer. m.j., n.c. turner, d.c. hardle, l.r. morton, l. morton and j.v. thomas. 2004. response to water deficit and high temperature of transgenic peas (pisum sativum l.). j. exp. bot. 55(396): 497-505. tewari, s.k. and m. singh. 1993. yielding ability of wheat at different date of sowing a temperature development performance. indian j. agron. 38(2): 204-209. bangladesh agron. j. 2022, 25(1): 23-36 farmers’ rice yield in fallow t. aman rice fallow cropping pattern due to variability in genotype and management n. parvin1, m.a. salam2, m.u. salam3, m.a. kader2, b. nessa4 1senior scientific officer, rice farming systems division, bangladesh rice research institute, gazipur-1701. 2professor, department of agronomy, bangladesh agricultural university, mymensingh-2202. 3freelance consultant, 115/3, east bhurulia, joydebpur, gazipur – 1700, bangladesh; 4senior scientific officer, plant pathology division, bangladesh rice research institute, gazipur1701. corresponding e-mail: nargisrfs@gmail.com (received: 02 march 2022, accepted: 29 march 2022) keywords: genotype, high yield potential, management, rice, yield variability abstract farmers’ existing rice production practices provide key indications of interventions for improving yield in their environments. this study aimed to explore those indications in the fallow t. aman rice fallow cropping pattern (cp) under rainfed farming practiced by the farmers in kapasia, gazipur. research method employed one-to-one and face-to face interview of 154 farmers practicing the cp. the average yield of t. aman was estimated as 3.23 t ha-1, slightly below the national average yield of 3.93 t ha-1, in the range of 1.18 to 5.65 t ha-1. variety was one of the two broad factors that determined the yield variation. the high yeld potential (hyp) category absolutely preferred the production aim, where swarna-ranjit (31.2% by farmer) and brri dhan49 (24.7% by farmer) were the dominated varieties where average yields were very close (3.51 and 3.36 t ha-1) for swarna-ranjit and brri dhan49, respectively). management was the second factor determining the yield variation within varieties. while both the varieties received similar maximum yield (5.65 t ha-1), swarna-ranjit produced the minimum yield of 1.40 t ha-1 and brri dhan49 of 1.98 t ha-1. this study did not find a consistent pattern of response of the three measured management components transplanting time, seedling age and seedling density to yield in either variety. the yield variance of brri dhan49 under three management components was higher compared to swarna-ranjit. farmers practiced relatively a wide range of three management combinations to achieve high yield in swarna-ranjit, but a narrow range of the three management combinations for brri dhan49 to achieve the same level of yield. it is concluded that the variety-specific agronomic management to be the avenue for yield improvements in farmers’ fields. introduction according to fao (2018), rice sector provides about 70 % of agricultural gdp; it also shares one-sixth of the national income of bangladesh. for this country, rice is the staple food; in addition, it is a dominant factor of social and political stability (nath, 2015). yield can be enhanced through improved genotype and management specific to environments (anderson et al., 2005). a number of studies support that high yield varieties coupled with appropriate management greatly contribute to increased yields (fischer and wall, 1976; byerlee and anderson, 1994; anderson et al., 2005; sarangi et al., 2016; salam, 2017). suitability of a genotype and its scope for management depend on environment to which the rice crop is cultivated. depending on the environment, cropping patterns are also developed and practiced. therefore, genotype and management aspects of yield are largely specific to cropping patterns. 24 parvin et al. rice is grown in about 3.20 million hectares of land under ‘rainfed low land’ system (rahman et al., 2020), accounting for about 27 % of the total rice area. this system is characterized by occasional flood and water stagnation at vegetative phase and periodic drought or moisture stress at reproductive phase of t. aman rice (rahman et al., 2020). the fallow t. aman rice fallow is a cropping pattern (cp) under this system. this cp covers 509,480 ha of land accounting for about 5.89 % of net cropped area (nasim et al., 2017), and 4.29 % of total rice area (based on 11.87 hectare of total rice area as of 2020 (rabbi et al., 2020). the fallow t. aman rice fallow cp spreads over 167 upazilas, and, being periodically stressed, characterized by low yield zone under poor genetic and/or crop management scenarios. thus, there is a scope of exploring yield potential in this environmentally constraint cropping pattern. for improving rice yield under the fallow t. aman rice fallow cropping pattern, information is necessary on farmers ‘existing rice production practices with respect to genotype and management components. keeping these views in mind the present study was designed to estimate farmers’ rice yield status in the fallow t. aman rice fallow cropping pattern; to record farmers variety choice, management practices and their influence on yield; and to map farmers’ rice yield of dominant varieties with respect to management. materials and methods this study was undertaken in kapasia upazila, gazipur district of bangladesh located in between 24°02' and 24°16' north latitudes and 90°30' and 90°42' east longitudes. it belongs to madhupur tract of the agro ecological zone (aez-28) which has unique combination of physiographic, edaphic, hydrological and agro climatic characteristics. this region is a complex relief where soil developed mostly as heavy grey clay under the madhupur clay. predominant general soil type are deep red brown terrace and shallow grey terrace soil and acid basin clays are the major ones. it comprises different kinds of landscape, mainly well drained dissected terrace and valleys and poorly drained level terrace. the aez covers 4,244 square kilometer area (fao, 1988). the composition of land type in the aez is 56% high, 18% medium high, 7% medium low, 9% low and 10% homestead and water bodies (fao, 1988). characteristically, soil texture is loamy, ph 4.8-5.5 (kumar et al., 2018). the soils are low (1.0 – 1.7%) in organic matter content and fertility (bbs, 2016). the net cropped area of the kapasia upazila is 19,600 hectare. among the cropping patterns, fallowt. aman rice – fallow occupies 1700 hectare of 8.7% of the net cropped area ( brri, 2021a) under rainfed cropping systems. the research site was undertaken through farmers’ survey in six (6) out of eleven (11) unions of the upazila. the six unions – chandpur, durgapur, kapasia sadar, rayed, targaon and tok – were selected as the farmers in the unions had been traditionally practicing the target cropping pattern. those six unions covered about 80% area under this cropping pattern during 2017 cropping season (kapasia upazila agriculture office, 2018). the sample size was 154 and drawn 33.1, 21.4, 18.2, 16.2, 9.1 and 1.9%, respectively, from chandpur, kapasia, tok, rayed, targaon and durgapur. semi-structured questionnaire was developed for collecting data. the questionnaire included rice variety, time of transplanting, seedling age, and seedling number per hill. the questionnaire was pre-tested before finalizing. survey was executed by face-to-face individual interviewing. the interviews were conducted during march to june 2018, where the interviewees were asked to respond the queries based on recalled data for t. aman rice growing season of 2017. data were collected as hard copy and entered in ms-excel. all data were tabulated with unique identifier and curated. during the curation process, where data were not clearly recorded and/or had confusion on understanding, the respected interviewees were contacted via mobile phone. in order to analyse structurally, the data categorised for (i) variety diversification, (ii) transplanting time, (iii) seedling age and (iv) seedling density. (i) variety diversification: farmers’ rice varieties were grouped into four categories in relation to product speciality. they were aromatic scented rice, high yield potential (fertilizer using efficiency is higher and has potentiality to give higher yield, hyp), market demand (high value rice varieties) that rice yield in fallow t. aman rice fallow cropping pattern 25 have demand in market for their taste at consumer level and photosensitivity (varieties which have photosensitivity to day length). (ii) transplanting time: the whole range of the rice transplanting time applied by the farmers was categorised at 15-day interval into five groups, very early (upto to 14 july), early (15-29 july), mid (30 july -13 august), late (14-28 august) and very late (after 28 august). (iii) seedling age: the whole range of the rice seedling age used by the farmers was categorised at 10day interval into four groups, younger (≤ 30), middle (31-40), older (41-50), and very older > 50. (iv) seedling density (seedling number per hill): the whole range of the rice seedling density used by the farmers was categorised into three groups, standard (≤ 3), high (4-5), and very high (> 5). distribution of farmers rice yields were analysed using analysis tool pack of ms-excel and presented as box-whisker graph and histogram. variety and management specific yields were compiled using pivot table fuction of ms-excel. yields were compared statistically using 95% confident interval. the yields under the groups of three management components (transplanting time, seedling age and seedling density were arranged in a matrix in ms-excel cells for the two dominant varieties used by the farmers, and presented in a map. results distribution of rice yield achieved by the farmers figure 1 reveals the distribution of rice yields of the sampled farmers in the study area under fallow t. aman rice fallow cropping pattern. the yields ranged from 1.18 to 5.65 t ha-1. the figure further shows that the middle 50% of the yield data concentrated within 2.82 to 3.70 t ha-1. the average and median of yields were recorded as 3.23 and 3.29 t ha-1, respectively. fig. 1. distribution of rice yield achieved by farmers in the fallow t. aman rice fallow cropping pattern in kapasia. box represents middle 50% of the yields, vertical line is the range, and within the box, horizontal line is the median and solid circle is the average. frequency distribution of the farmers’ rice yields is presented in figure 2. results reveal that, yields in the study area more or less followed normal distribution. the maximum frequency (24.0%) of farmers received the yield of 2.5 3.0 t ha-1, followed by 22.1 and 20.8% received 3.5 4.0 and 3.0 3.5 t ha-1, respectively. a small segment of farmers (7.8%) received comparatively low yield (≤ 2.0 t ha-1); on the other hand, 14.9% of the surveyed farmers achieved comparatively high yield (≥ 4.0 t ha-1). 26 parvin et al. fig. 2. frequency distribution of rice yield obtained by the farmers in fallow t. aman rice fallow cropping pattern in kapasia, gazipur. farmers’ chosen rice varieties in the study area, the farmers grew as many as 13 rice varieties (figure 3). data shows that, among the varieties, swarna–ranjit was the most preferred variety which was chosen by 31.2% farmers, closely followed by brri dhan49, adopted by 24.7% farmers. relatively smaller number of farmers used swarna–guti (8.4%), brri dhan51 (7.8%), pajam (7.1%), kaishabinni (7.1%), hurabdi (3.9%), br11 (2.6%), kalizira (1.9%), nizershail (1.9%), brri dhan41 (1.3%), br22 (1.3%) and brri dhan34 (0.6%) respectively. only 13.0% surveyed farmers grew local varieties (kaishabinni, hurabdi and kalizira). fig. 3. status of farmers’ rice variety choice in the fallow t. aman rice fallow cropping pattern in kapasia, gazipur. farmers’ chosen rice varieties according to purpose of growing according to purpose of growing, farmers had broadly chosen four categories of rice varieties. they were ‘aromatic’ (var. brri dhan34 and kalizira), ‘high yield potential’ (var. br11, brri dhan41, brri dhan49, brri dhan51, swarna-guti and swarna-ranjit), market demand (var. nizershail and pajam) and photosensitivity (var. br22, hurabdi and kaisha binni). absolute majority of the farmers rice yield in fallow t. aman rice fallow cropping pattern 27 (76.0%) grew rice varieties under the high yield potential category. only small number of farmers cultivated varieties that belonged to photosensitivity (12.3%), market demand (9.0%) and aromatic (2.5%) category. fig. 4. status of farmers’ rice variety group by the purpose of growing in the fallow t. aman rice fallow cropping pattern in kapasia, gazipur. hyp = denotes for high yield potential. farmers’ chosen rice varieties according to purpose of growing – the distribution of yields figure 5 presents the distribution of rice yields achieved by the farmers under the four categories of purpose of growing. the highest average yield was achieved from the, high yield potential (hyp) group (3.41 t ha-1) followed by market demand (2.87 t ha-1) and photosensitivity (2.73 t ha-1) and the lowest in the varieties under aromatic group (1.72 t ha-1). range of yield in the hyp varieties was 1.40 to 5.65 t ha-1 where the middle 50% of the yield data concentrated between 2.82 and 3.94 t ha-1. on the other hand, the range of yield of market demand varieties was 1.69 to 3.94 t ha-1 where middle 50% of the yield data concentrated between 2.15 to 3.51 t ha-1. for the photosensitivity group, the range of yield was 1.41 to 3.55 t ha-1, with the middle 50% of the yield data concentrated between 2.37 and 3.06 t ha-1. under the aromatic rice group, where the average yield was the lowest, the farmers received the yield in the range of 1.18 to 2.96 t ha-1 with the middle 50% of the yield between 1.28 and 1.80 t ha-1. 28 parvin et al. fig. 5. distribution of farmers’ rice yield according to purpose of growing in fallowt. aman rice fallow cropping pattern in kapasia, gazipur. box represents middle 50% of the yield, vertical line is the range, and within the box, horizontal line is the median and solid circle is the average. values inside the figure denote for sample number within variety group. hyp = denotes for high yield potential. farmers’ chosen rice varieties under high yield potential (hyp) group results show that, two rice varieties (swarna-ranjit and brri dhan49) accounted for about 60% of farmers’ choice in the study area of which swarna-ranjit was 31.25% and that of brri dhan49 was 24.7% (figure 6). with respect to other varieties, swarna-guti was chosen by 8.4%, brri dhan51 (7.8%), br11 (2.6%), brri dhan41 (1.3%) of the surveyed farmers. fig. 6. status of farmers’ rice variety choice for high yield potential (hyp) in fallow t. aman rice fallow cropping pattern in kapasia, gazipur. rice yield in fallow t. aman rice fallow cropping pattern 29 yield distribution of swarna-ranjit and brri dhan49, the most chosen varieties under the high yield potential (hyp) group as mentioned earlier that swarna-ranjit and brri dhan49 were the most chosen rice varieties in the study area under the high yield potential (hyp) group. it was observed that both the varieties received similar maximum yield (5.65 t ha-1). however, swarna-ranjit produced the minimum yield of 1.40 t ha-1 and brri dhan49 of 1.98 t ha-1. the figure 7 further shows that the middle 50% yield data of brri dhan49 and swarna-ranjit was found from 2.82 to 3.83, and 3.12 to 4.0 t ha-1, respectively. the average yield of 3.51 t ha-1 was found from swarna-ranjit and 3.36 t ha-1 from brri dhan49. the median yield of 3.51 and 3.39 t ha-1 was received from swarna-ranjit and brri dhan49, respectively. the figure 7 shows that the middle 50% of yields in swarna-ranjit ranged between 3.12 and 4.0 t ha-1 whereas with brri dhan49 was 2.82 and 3.83 t ha-1. fig. 7. rice yield distribution of brri dhan49 and swarna-ranjit, the most chosen varieties, in the fallow t. aman rice fallow cropping pattern in kapasia, gazipur. box represents middle 50% of the yields, vertical line is the range, and within the box, horizontal line is the median and solid circle is the average. values inside the figure denotes for sample number within variety group. management in rice varieties by the farmers under the variety choice scenario in the study area, it is already reported the farmers almost equally using brri dhan49 and swarna-ranjit. therefore, the variety management aspect highlights on those two varieties. management in rice varieties (transplanting time): for brri dhan49, the yield (1.98 t ha-1) was significantly lowest at the very early transplanting window, which significantly increased to 3.68 t ha-1 in the early transplanting (figure 8). the yield then declined in subsequent transplanting windows. however, this decline was not statically significant. on the contrary, for swarna-ranjit, the yield (3.81 t ha-1) from very early transplanting window was comparable to other transplanting windows. the lowest yield (3.23 t ha-1) was obtained in early transplanting window which significantly increased to 3.99 t ha-1 in the mid transplanting. the yield then declined gradually in later transplanting windows but those declines were not significant. 30 parvin et al. fig. 8. response of transplanting time on rice yield in the fallow t. aman rice fallow cropping pattern in kapasia upazila of gazipur district, bangladesh. vertical bars represent 95% confidence intervals of the farmers’ yields within each defined transplanting window. management in rice varieties (seedling age): in brri dhan49, yield decreased with the increasing of seedling age but differences were not significant (figure 9). in swarna-ranjit younger seedlings produced an average yield of 3.50 t ha-1, which increased to 3.72 t ha-1 in the middle-aged seedlings; afterwards, the yield gradually decreased with older and very older seedlings (figure 9). fig. 9. response of seedling age on rice yield in the fallow t. aman rice fallow cropping pattern in kapasia, gazipur. vertical bars represent 95% confidence interval of the farmers’ yields within each defined seedling age group. management in rice varieties (seedling density): yield decreased with the increase of seedling density in brri dhan49 (figure 10). however, with swarna-ranjit, no yield difference was found between high and very high seedling density. rice yield in fallow t. aman rice fallow cropping pattern 31 fig. 10. response of seedling density on rice yield in the fallow t. aman rice fallow cropping pattern in kapasia upazila of gazipur district, bangladesh. vertical bars represent 95% confidence interval of the farmers’ yields within each defined seedling age group. comparing the variance in rice yield of two varieties under three management practices the yield variance of brri dhan49 under three management components was higher compared to swarna-ranjit (figure 11). the yield variance for transplanting time window in brri dhan49 was higher (0.43 t ha-1) comparted to swarna-ranjit (0.11 t ha-1). in brri dhan49, seedling age accounted for a yield variance of 0.15 t ha-1, slightly higher than swarna-ranjit (0.10 t ha-1). the variance of yield for seedling density was high between the two varieties (0.32 and 0.20 t ha-1 for brri dhan49 and swarna-ranjit, respectively). fig. 11. comparing variance in rice yield for two varieties under three management components in fallow t. aman rice fallow cropping pattern in kapasia upazila of gazipur district, bangladesh. mapping of farmers’ rice yield under brri dhan49 and swarna-ranjit 32 parvin et al. among the possible 60 combinations of three management components (five transplanting time window, four seedling age group and three seedling density group), brri dhan49 was used in 16 and that of swarna-ranjit in 23 combinations (figure 12). fig.12. mapping farmers’ rice yield (shade), together with respective frequency (number in the shade), for two varieties under three management combination (transplanting time, seedling age and seedling density) in fallow t. aman rice fallow cropping pattern in kapasia upazila of gazipur district, bangladesh. about 68% farmers grew brri dhan49 in six combinations of management transplanting in early or mid-windows, using younger or middle or older seedings, and all under high seedling density. about 67% of the farmers who achieved the highest level of yields (> 4.0 t ha-1) for this variety, belonged to this management segment. on the contrary, about 46% farmers grew swarna-ranjit in the same six combinations of management. only about 38% of the farmers who achieved the highest level of yields (> 4.0 t ha-1) for this variety, belonged to this management segment. discussion this study investigates the insights of farmers’ rice yield and its variability in the rainfed-based fallow t. aman rice fallow cropping pattern in kapasia, gazipur. rice crop under this pattern can get stressed as provision of supplementary irrigation is missing due to lack of facilities. in relation to the first objective, the average yield status of the surveyed farmers was 3.23 t ha-1. this yield was slightly below the national average of t. aman rice yield, 3.93 t ha-1 (equivalent clean rice yield of 2.63 t ha-1 as of 2019-20 data, brri, 2021b). the yield, however, was not similar to all the farmers; it spread from 1.18 to 5.65 t ha-1 indicating some farmers performed well and some did not. farmers’ yield variability within a region is expected because the systems with which the farmers grow rice is likely to be different to one another. the systems include choice of variety and management components. rice yield in fallow t. aman rice fallow cropping pattern 33 variety plays an important role in yield variation in t. aman season, like all other rice types. varietal difference during the season can cause large variation in yield as wide as 2.60 and 5.50 t ha-1 (brri, 2012a; brri, 2013; brri, 2014a; brri, 2014b; brri, 2018). in relation to the second objective, it was observed that farmers grew as many as 13 varieties which impacted on yield variation. for example, kalizira yielded as low as 1.18 t ha-1, whereas both brri dhan49 and swarna-ranjit yielded 5.65 t ha-1. other studies also show much lower yield in aromatic rice compared to hyp group (singh et al., 2000; hossain et al., 2008). the major thrust of the farmers, however, was to achieve high yield as the survey revealed as high as 76% of them choose varieties for hyp group. the study observed that the yields varied according to the variety-type targeted by the farmers. six rice varieties were cultivated under hyp group, where the two varieties, brri dhan49 and swarna-ranjit, accounted for about three-quarter of the choice, 41 and 33%, respectively, among this category. of the two widely chosen varieties in the study area, the average yield of swarna-ranjit was slightly higher (~5%) than brri dhan49. the yield potential of a variety can be influenced by management (lampayan et al., 1994; anderson et al., 2005; alam et al., 2013; sarangi et al., 2016). this study specifically investigated management factors influencing the yield of brri dhan49 and swarna-ranjit, those two varieties were dominant in the studied cropping pattern. the very early transplanting negatively impacted the yield in brri dhan49 (brri, 2012b), the effect of transplanting time was not evident in swarna-ranjit. in recent observations, brri dhan49 was found to express erratic flowering behaviour during early transplanting times (pre-mid-july), probably because of its reaction to photoperiod (brri, personal communication). the older aged seedlings tended to reduce yield, though insignificantly, in brri dhan49, but it was not the case for swarna-ranjit, except for the very old seedlings (over 50 days). the pattern of yield response in brri dhan49 to seedling age was similar to that reported by hasanuzzaman et al. (2014) for the same variety who found decreased yield with increased seedling age of 25 day-old onward. on the contrary, no significant yield variation for seedling age in the range of 30 to 60 days was found for brri dhan49 (yasmeen et al., 2016). a lower yield was achieved in both the varieties when the seedling density was used over 3 per hill; which corroborates with the var. br11, brri dhan32 and brri dhan33 (alam et al., 2012) and hashemi (bozorgi et al., 2011). taking the response of the three management components together, the variance of yield in brri dhan49 was more than swarna-ranjit especially with respect to transplanting time and seedling density (number hill-1). swarna-type varieties occupied 20.68% of t. aman rice area compared to 14.30% by brri dhan49 (brri, 2020). however, in stressed area such as in the northern region (dinajpur, rajshahi and rangpur) the adoption of swarna-type varieties was 7 to 16 times higher than brri dhan49 (brri, 2020). it may be noted that swarna-ranjit is a mega variety for low land in rainfed rice system in assam, india, covering 50% area (chetia, 2018). farmers achieved high level of yields by concentrating on few specific combinations of management of var. brri dhan49 transplanting in early window, using younger or middle aged seedlings with standard or high seedling density. on the other hand, farmers who grew swarna-ranjit adopted diverse combinations of management to achieve high level of yields. the findings indicate that the farmers are already experienced with the suitable management options transplating high yield for brri dhan49, and probably not for swarnaranjit. it may also reveals that the yield potential of swarna-ranjit can be explored in wide variety of management options. the issues of response of yield in ‘swarna-ranjit’ to management options should need to be thoroughly investigated in future research. conclusion farmers obtained wide range of yield of rice under the fallow t. aman rice fallow cropping pattern in the study area. relatively a wide range of three management combinations (transplanting time, 34 parvin et al. seedling age and seedling density) was employed to achieve high yield in var. swarna-ranjit under high yield potential. on the contrary, var. brri dhan49, under the same growing purpose produced high yield under narrow range of the three management combinations. it is concluded that the thrust for yield improvements in farmers’ fields should centre around variety-specific agronomic management. acknowledgements this study is a part of first author’s on-going phd research in the department of agronomy of the bangladesh agricultural university (bau). the project implementation unit (piu), national agricultural technology program – phase ii project (natp-2) of the bangladesh agricultural research council (barc) offered a phd fellowship, and the bangladesh rice research institute (brri) granted study leave and provided with research facilities to run the phd programme np deeply acknowledges both natp-2 and brri for that. np also thanks the sub-assistant agriculture officers (saaos) of department of aagricultural extension (dae) at kapasia upazila for providing information related with this study. references alam, m.s., m.a. baki, m.s. sultana, k.j. ali and m.s. islam. 2012. effect of variety, spacing and number of seedlings per hill on the yield potentials of transplant aman rice. int. j. agron. agri. r. 2(12): 10-15. https://www.innspub.net/wp-content/uploads/2021/12/ijaar-vol-19-no-5p-1-9.pdf. alam, m.m., m.r. karim and j.k. ladha. 2013. integrating best management practices for rice with farmers’ crop management techniques: a potential option for minimizing rice yield gap. field crop res. 144: 62-68. https://doi.org/10.1016/j.fcr.2013.01.010. anderson, w.k., m.a. hamza, d.l. sharma, m.f.d. antuono, f.c. hoyle, n. hill, b.j. shackley, m. amjad and c. zaicou-kunesch. 2005. the role of management in yield improvement of the wheat crop—a review with special emphasis on western australia. aust. j. agric. res. 56: 1137–1149. https://doi.org/10.1071/ar05077. bbs. 2016. yearbook of agriculture 2015. bangladesh bureau of statistics (bbs), statistics and informatics division (sid), ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh, p.9. bozorgi, h.r., a. faraji, r.k. danesh, a. keshavarz, e. azarpour and f. tarighi. 2011. effect of plant density and yield components of rice. world appl. sci. j. 12(11): 2053-2057. http://idosi.org/wasj/wasj12(11)/17.pdf. brri. 2012a. brri annual report 2009-2010. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.211. brri. 2012b. brri annual report 2009-2010. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.327. brri. 2013. brri annual report 2010-2011. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.262. brri. 2014a. brri annual report 2011-2012, bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.334. brri. 2014b. brri annual report 2012-2013. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.317. https://www.innspub.net/wp-content/uploads/2021/12/ijaar-vol-19-no-5-p-1-9.pdf https://www.innspub.net/wp-content/uploads/2021/12/ijaar-vol-19-no-5-p-1-9.pdf https://doi.org/10.1016/j.fcr.2013.01.010 https://doi/ http://idosi.org/wasj/wasj12(11)/17.pdf rice yield in fallow t. aman rice fallow cropping pattern 35 brri. 2018. brri annual report 2017-2018, bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.331. brri. 2020. annual research review xv agricultural economics division. annual research review workshop 2019-20. bangladesh rice research institute, gazipur 1701, bangladesh, p.3. brri. 2021a. cropping pattern, intensity and diversity in dhaka region. bangladesh rice j. 21(2): 1155. http://www.brri.gov.bd/site/page/55d231c8-8ba2-46d9-93bf-a63d5aa129a4. brri. 2021b. bangladesher dhaner jomi, uthpdan o pholoner data (rice area, production and yield in bangladesh). rice database. http://www.brri.gov.bd/site/page/f6e878c8-ceac-402d9bed-6fb29a787428. byerlee, d. and j.r. anderson. 1994. technology transfer systems for improved crop management: lessons for the future. in: agricultural technology: policy issues for the international community. commonwealth agricultural bureaux international, cambridge, uk. pp.208– 230. chetia, s.k., m. kalita, r.k. verma, b. barua, t. ahmed, m.k. modi and n.k. singh. 2018. flood proofing of ranjit, a popular variety of north-eastern india through transfer of sub1 rice qtl by modified marker-assisted backcross breeding. indian j. genet. 78(2): 166-173. doi: 10.5958/0975-6906.2018.00021.4. fao. 1988. land resources appraisal of bangladesh for agricultural developmentreport 2: agro ecological regions of bangladesh. food and agriculture organization of the united nations, rome, italy, p.570. https://www.fao.org/3/s7223e/s7223e.pdf. fao. 2018. rice prices and growth, and poverty reduction in bangladesh. background paper to the unctad-fao commodities and development report 2017 commodity markets, economic growth and development. food and agriculture organization of the united nations, rome, p.35. https://www.fao.org/3/i8332en/i8332en.pdf. fischer, r.a. and p.c. wall. 1976. wheat breeding in mexico and yield increases. j. australian inst. agric. sci. 42: 139–148. hasanuzzaman, m., m.a. hasan, m. sadekuzzaman, m.m. bahadur and m.r. islam. 2014. dry matter accumulation, leaf characteristics and yield of aman rice as influenced by seedling ages. j. bangladesh soc. agric. sci. technol. 11(1&2): 35-40. hossain, m.f., m.s. islam, m.m. rahman, m.o. faruk and m.g. ershad. 2008. yield and quality performance of some aromatic rice varieties of bangladesh. j. agrofor. environ. 2(2): 155158. https://www.academia.edu/15192562. kumar, u., m. mukta and m.y. mia. 2018. changes in soil properties of four agro-ecological zones of tangail district in bangladesh. progressive agriculture. 29(4): 284-294. doi: https://doi.org/10.3329/pa.v29i4.41342. lampayan, r.m., a.f.m. saleh, s.i. bhuiyan and m.a. lantican. 1994. a cognitive model of farmers’ rice crop establishment decisions in rainfed lowlands. in: proceedings of the international agricultural engineering conference. asian institute of technology, bangkok, thailand, december, 1994. pp.727–739. nasim, m., s.m. shahidullah, a. saha, m.a. muttaleb, t.l. aditya, m.a. ali and m.s. kabir. 2017. distribution of crops and cropping patterns in bangladesh. bangladesh rice j. 21(2): 1-155. https://www.banglajol.info/index.php/brj/article/view/38195. http://www.brri.gov.bd/site/page/55d231c8-8ba2-46d9-93bf-a63d5aa129a4 http://www.brri.gov.bd/site/page/f6e878c8-ceac-402d-9bed-6fb29a787428 http://www.brri.gov.bd/site/page/f6e878c8-ceac-402d-9bed-6fb29a787428 https://www/ https://www/ https://www.academia.edu/15192562/ https://doi.org/10.3329/pa.v29i4.41342 https://www.banglajol.info/index.php/brj/article/view/38195 36 parvin et al. nath, n.c. 2015. food security in bangladesh: status, challenges and strategic policy options. paper presented at 19th biennial conference of the bangladesh economic association (bae), held on 8-10 january, 2015, dhaka, bangladesh. https://bea-bd.org/site/images/pdf/080.pdf. rabbi, s.m.h.a, p.l. biswas, e.s.m.h. rashid, n.m.f. rahman, k.m. iftekharuddaula, m.s. rahman, m.a.r. sarkar, m.a.a. mamun, m.u. salam and m.s. kabir. 2020. increasing rice yield through targeting genetic potentials by rice types. bangladesh rice j. 24 (2) : 67-82. doi: https://doi.org/10.3329/brj.v24i2.53449. rahman, m.s., m.m. haque, m.j. kabir, a.k.m.s. islam, m.a.r. sarkar, m.a.a. mamun, m.u. salam and m.s. kabir. 2020. enhancing rice productivity in the unfavorable ecosystems of bangladesh. bangladesh rice j. 24(2) : 83-102. doi: https://doi.org/10.3329/brj.v24i2.53450. salam, m.u. 2017. improving productivity of mungbean in south-central region of bangladesh. consultancy report. usaid-aesa project, house no.7, road no. 2, banani, dhaka-1213, bangladesh. http://www.aesabd.org/download/aesa-mungbean-study-report-oct-2017.pdf. sarangi, s.k., b. maji, s. singh, d.k. sharma, d. burman, s. mandal, u.s. singh, a.m. ismail and s.m. haefele. 2016. using improved variety and management enhances rice productivity in stagnant flood-affected tropical coastal zones. field crop res. 190: 70-81. https://doi.org/10.1016/j.fcr.2015.10.024. singh, k., u.s. khush, g.s. khush and r. rohilla. 2000. genetics and biotechnology of r quality traits in aromatic rices. in: aromatic rices, r.k. singh, u.s. singh and g.s. khush (eds.). oxford & ibh publishing co. pvt. ltd. new delhi, india, pp.47-69. http://books.irri.org/8120414209_content.pdf. yasmeen, r., s. akter, t. halder, a. biswas, m.m. rahman and l. ferdousi. 2016. performance study of some t. aman varieties under normal transplanting and double transplanting system. saarc j. agric. 14(1): 37-45. doi: https://doi.org/10.3329/sja.v14i1.29574. https://bea/ https://doi.org/10.3329/brj.v24i2.53449 https://doi.org/10.3329/brj.v24i2.53450 http://www.aesabd.org/download/aesa-mungbean-study-report-oct-2017.pdf https://doi.org/10.1016/j.fcr.2015.10.024 http://books.irri.org/8120414209_content.pdf https://doi.org/10.3329/sja.v14i1.29574 bangladesh agron. j. 2020, 23(2): 97-102 yield and physiological indices of lentil genotypes against drought stress b. ahmed 1 , a.s. mitu 2 , m. sultana 3 , n. tasnim 4 and a.h.m.m.r. talukder 5 135 bangladesh agricultural research institute, gazipur-1701 2 bangladesh suger crop research institute, pabna-6620 4 sher-ebangla agricultural university, dhaka-1207 corresponding e-mail: bulbul@bari.gov.bd (received: 13 october, 2020, accepted: 01 november, 2020) keywords: ascorbate peroxidase (apx), catalase (cat), peroxide dismutase (pod), malondialdihyde (mda) physiological indices, drought, lentil abstract four lentil genotypes/varieties blx-010014-9, ili-5143, bari mosur-3 and bari mosur-2 were given irrigation regimes (with and without irrigation) to evaluate the physiological indices of genotypes against drought stress. the experiment was conducted during rabi (winter) season of 2017-18 under pot culture at the plant physiology division of bangladesh agricultural research institute (bari). the experimental design was randomized completed block (rcbd) with six replications. irrespective of genotypes/varieties, physiological parameters as well as seed yield were greatly affected due to irrigation regimes. based on physiological parameters like accumulation of chlorophyll, enzymatic and non-enzymatic antioxidantthe genotype blx-010014-9 was found to be drought tolerant due to its higher and lower values of enzymatic and nonenzymatic antioxidant indices (greater cat, pod, apx and lower mda) across the irrigation levels treatment. this genotype may be further explored to characterize its genes and mechanisms against drought stress for increased lentil production and way to developing the drought tolerant variety/varieties. introduction among the various abiotic stresses, drought is a great crop yield limiting phenomenon in many areas of the world (rahimi, 2016). directly or indirectly, drought affects at morphological, physiological, biochemical and molecular levels of crops (saeedipour, 2012) that adversely reduce the plant growth and productivity (wang et al., 2001). estimated yield reduction for cereal crops like maize and wheat were up to 21% and 40%, respectively due to severe drought as reported by daryanto et al. (2016). legume crop like lentil is also vulnerable to drought stress at reproductive growth stage that limits its yield (farooq et al., 2016) by 6 to 54% (oweis et al., 2004). acclimation of plants to drought stress is the result of adaptive changes in plant growth and physiological processes. it is well known that abiotic stresses can cause oxidative damage to plants, either directly or indirectly through the formation of reactive oxygen species (ros) while plants survive with the increasing production of antioxidant enzyme like ascorbate peroxidase (apx, ec.1.11.1.11), catalase (cat, ec 1.11.1.6) and peroxide dismutase (pod, ec 1.15.1.1) which can scavenge ros as a physiological mechanism of drought tolerance (das and choudhary, 2016). so, this mechanism can play a vital role for breeder to identify lentil genotypes, keep on high level yield production under drought conditions. earlier ahmed et al. (2016) observed the genotype blx-010014-9 as most drought tolerant giving comparative relative yield where physiological mechanism is needed to be explored. hence, this experiment was conducted to explore the changes in physiological responses against drought tolerance indices of lentil. 96 ahmed et al. materials and methods an experiment was conducted in pot house of plant physiology division of bari to evaluate the yield differences and physiological mechanism of lentil genotypes against drought tolerance indices. the experiment was conducted during november, 2017 to february, 2018. earlier selected four lentil genotypes/varieties, blx-010014-9, ili-5143, bari moshur-3, and bari moshur-2 based on their relative yield performance under drought conditions were used in this experiment under. the test crops were grown under irrigation (control) and drought (no irrigation) conditions. the control plants were maintained with proper irrigation started at 30 days after sowing (das) while the other set of plants were subjected to water stress by withholding irrigation during whole growing period. the study was laid out in randomized complete block design with six replications and each pot was considered as one replication. to carry out the experiment total 48 (26 cm top diameter, 20 cm base diameter and 25 cm in height) pots were arranged with placement of 24 pots in two replicate blocks in the pot house. soil and well decomposed farm yard manure were mixed properly in 4:1 volume ratio and kept in each pot containing 12 kg of soil. fertilizers @ 12-16-20-12-1.0-0.5 kg ha -1 of n-pk-s-zn-b were applied in the form of urea, triple super phosphate, muriate of potash, sulphur and zinc sulphate and boron, respectively (frg, 2012). each pot received double rate of 0.16-0.48-0.24-0.42-0.16-0.018 g urea, triple super phosphate, muriate of potash, sulphur and zinc sulphate and boron, respectively. provax200 wp treated seeds were sown on 27 november, 2017. seven to ten healthy and uniform size seeds were sown each pot as per variety arrangement. subsequently, five healthy seedlings in each pot were maintained. crop growth and physiological parameters were recorded with time. to measure the physiological parameters sampling was done on sunny days within the period of 11.00 am to 1.30 pm when drought stress symptoms were visible in crops. physiological parameter chlorophyll accumulation of leaves (mg g -1 fw) second or third leaf sample from plant of each plot was collected and weighed out in 0.5 g (fresh weight). then the sample was treated using 10 ml (v) of 80% acetone approximately 48 hours until the leaf turned white under dark condition. the optical density was measured with uv-1800 spectrophotometer (shimadzu, japan) against 80% acetone as blank at 663nm (od663) and at 645 nm (od645) for chlorophyll a (chl a) and chlorophyll b (chl b), respectively. the chlorophyll concentrations (chl) were determined using following formula as described by arnon (1994). chl a (mg g -1 ) = [12.7 (od 663)-2.69(od645)] × v/ (1000×w) chl b (mg g -1 ) = [22.9 (od 645)-4.68(od663)] × v/ (1000 ×w) total chlorophyll (mg g -1 ) = [20.2 (od 645) + 8.02 (od 663)] × v/ (1000×w) bio-chemical analysis enzyme extraction and assays to perform bio-chemical analysis fully expanded 3 rd leaf from the top of plant of each plot was collected and kept in laboratory within zipper bag keeping in ice box. using a pre-cooled mortar and pestle, 0.5 g of leaf tissue was homogenized in 8 ml of 50 mm ice-cold tris-hcl buffer buffer (ph 7.2) containing 1mm na2hpo.12h2o and 1mm nah2po4.2h2o. the homogenates were centrifuged at 10,000×g for 20 minute. supernatants were collected after centrifugation and used to determine biochemical compounds such as cat, pod and mda. the collected supernatant was stored at 4 °c temperature until use. all biochemical activities were performed by shimadzu uv spectrophotometer (uv-1800). catalase (cat, ec: 1:11:1.6): catalase activity was carried out in a 3-ml reaction volume containing 2.8 ml of 50 mm tris-hcl buffer (ph 7.2, not containing edta), 100 µl of enzyme extract and 100 µl of 300 mm h2o2 from 30% h2o2 was taken in a quevette which was placed in measuring chamber of yield and physiological indices of lentil genotypes 97 uv spectrophotometer. activity was determined at 240 nm wavelength, which measures the decrease in absorbance for 30 second. the activity was calculated using the extinction coefficient of 39.4 mm cm -1 according to wu et al. (2003). peroxidase (pod, ec 1.11.1.7): pod activity was carried out in a 3-ml reaction volume containing 2.7 ml of 50 mm tris-hcl buffer (ph 7.2, not containing edta), 100 µl of enzyme extract and 100 µl of 1.5% guaicol, 100 µl of 300 mm h2o2 from 30% h2o2 was taken in a quevette which was kept in measuring chamber of uv spectrophotometer. activity was determined at 240 nm wavelength, which measures the decrease in absorbance for 1 min. the activity was calculated using the extinction coefficient of 39.4 mm cm -1 according to wu et al. (2003). mda (lipid peroxidation) assays: malondialdihyde (mda) (lipid peroxidation) was measured as per protocol of wu et al. (2003). 1.5 ml plant enzyme extract and 2.5 ml reaction solution (5% trichloroacetic acid + 0.6% thiobarbituric acid) was mixed together in a small tube and gave in hot water bath at 95 °c for 15 minutes and then gave immediately in ice bath. subsequently, the reaction solution was centrifuged @ 4800 rpm for 10 minutes. the absorbance of the supernatant was recorded at 532 nm. correction of non-specific turbidity was made by subtracting the absorbance value read at 600 nm. the level of lipid peroxidation was expressed as nmol g −1 fresh weight, with a molar extinction coefficient of 0.155 mmcm −1 . ascorbate peroxidase (apx, ec: 1.11.1.11) activity was assayed following the method of chen et al. (2010). the reaction buffer solution contained 50 mm k-phosphate buffer (ph 7.0), 0.5 mmasc, 0.1 mm h2o2, 0.1 mm edta, and enzyme extract in a final volume of 0.7 ml. the reaction was started by the addition of h2o2, and the activity was measured by observing the decrease in absorbance at 290 nm for 1 min using an extinction coefficient of 2.8 mm −1 cm −1 . agronomic parameters at maturity stage three plants from each treatment combination were collected and agronomic parameters like plant height, pods plant -1 , seeds pod -1 , 100-seed weight and seed yield plant -1 was recorded. the recorded data were statistically following mstat-c. the treatment means were compared by least significant difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion synthesis of antioxidant enzyme under drought condition stress generally induces accumulation of free radicals or ros and causes oxidative fracture in plant cells. the synthesized antioxidant enzyme by stressed cultivars/varieties scavenges the ros. overall, activity in synthesis of antioxidant enzyme like pod, cat, apx, and mda by different lentil genotypes under drought stressed compared with the unstressed is given below. drought tolerance or sensitivity of a genotype/variety is positively related with synthesize of antioxidant enzyme (chutipaijit, 2016). water stress significantly increased pod activity in all cultivars except the genotype ili-5143. bari mosur-2 and blx-010014-9 synthesized 15.73% and 12.95% higher pod under drought condition comparing with control. the genotype ili-5143 synthesized 86.0% lower pod which indicates the drought sensitivity of it (figure 1a). the measured activities of an antioxidant enzyme like ascorbate peroxidase (apx) were synthesized significantly higher in genotype/cultivar blx-010014-9 and bari mosur-3 under drought and control (irrigated) conditions. the genotype/variety blx-010014-9, ili-5143 and bari mosur-2 synthesized 327.4%, 336.9% and 95.4% higher apx under drought environment over control (figure 1b). 98 ahmed et al. fig. 1. effect of drought stress on enzymatic antioxidant (a) peroxide dismutase (pod), (b) ascorbate peroxidase (apx), (c) catalase (cat) and non-enzymatic antioxidant (d) malondialdihyde (mda) activities in lentil genotypes/varieties comparing with control catalase activity (cat) was measured in four lentil varieties/cultivars when wilting symptom was sharply appeared under drought condition (figure 1c). compared with the control, there was significantly higher cat activity upon exposure to drought stress in genotype/cultivar blx010014-9 and bari mosur-2. the accumulation of higher level cat enhanced scavenging ability for h2o2 in cultivar blx-010014-9 and bari mosur-2 inhibited the accumulation of ros and thus protected the plants from lipid peroxidation of membrane systems and oxidative damages under drought stress. cell membrane damage was monitored by mda (malondialdehyde) content of the leaf and which showed maximum values in all the studied lentil varieties/genotypes subsequent to water stress condition thus reflects the lower extent of tolerance to drought. hameed et al. (2011) reported that higher drought tolerance cultivar shows lower mda value when subjected to stress. all species exhibited a significant rise in their mda content subsequent to drought stress except for genotype blx-010014-9. at this point, the increase was much higher in bari mosur-3 and ili-5143 which was 75.6% and 65.1%, respectively over control. the lowest mda value was found in genotype blx010014-9 which was 26.7% over control (figure 1d). consequently the higher values of antioxidant enzymes and lower value of mda suggested the genotype blx-010014-9 as drought tolerant which can prevent the cell membrane damages effectively under drought stress. effect of drought stress on accumulation of photosynthetic pigment all genotypes significantly reduced the accumulation of chlorophyll pigment like chlorophyll a, chlorophyll b and total chlorophyll when subjected to drought stress. under restricted water supply 0 20 40 60 80 100 120 p o d a ct iv it y ( m m g -1 f w -1 ) control drought 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 a p x ( m m g -1 f w -1 ) control drought 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 c a t a ct iv it y ( m m g -1 f w -1 ) control drought 0.0 5.0 10.0 15.0 20.0 25.0 30.0 m a lo n d ia ld e h y d e ( m d a ) (g m o l-1 f w -1 ) control drought a b c d yield and physiological indices of lentil genotypes 99 condition the variety bari mosur-3 significantly reduced the (55.1%) chlorophyll a pigment over control. but, all cultivars/varieties showed the significant inverse relations under drought for the accumulation of chlorophyll b pigment. chl b content decrease was evaluated till 25% in genotype blx-010014-9 and 53% in variety bari mosur-3. total chlorophyll content decreased in blx010014-9 by (33.9%), ili-5143 (34%) and bari mosur-3 (51.0%), and increased in bari mosur-2 (2.60%). the reduction of total chlorophyll (chl, a+b) under drought stress indicates the inferior capacity for light harvesting by genotypes. similarly, the result of the study agreement with the study of mafakheri et al. (2010) who described that drought stress significantly decreased chlorophyll a, chlorophyll b and total chlorophyll content chickpea cultivars. fig. 2. accumulation of chl a, chl b and total chlorophyll (a+b) of different lentil genotypes/varieties under drought condition morphological growth, yield contributing and yield parameters of lentil irrespective of lentil varieties the plant height was reduced 10.86% under drought condition over control (table 1). genotype ili-5143 showed the tallest plant (38.62cm) and followed by the genotype blx-010014-9 (33.65cm) along with irrigation. even both cultivars had better performance under drought conditions (33.29, 31.27cm, respectively) over others. bari mosur-2 showed shorter plants (25.85cm) with drought treatment even it was poor (30.25cm) in irrigated condition compare to others indeed (table 1). the declination of plant height in drought stress can be owing to the relative reduction of augmentation and water loss of the protoplasm (nonami, 1998) which causes to the reduction of turgor pressure and cell division (taiz and zeiger, 2006). yield supporting components act as a noble indicators under drought stress and our study showed the significant reduction in number of pods plant -1 , 100-seed weight and yield under drought stress condition. similarly, asfaw and blair (2014) also reported that yield and yield supporting components were reduced significantly in common beans under drought stress. irrespective of genotypes/varieties the highest number of pods plant -1 were found when they were grown under irrigated condition which was 24.7% higher over drought condition. the genotype blx-010014-9 showed the highest pods plant -1 (45.63) followed by the genotype ili-5143 (42.13) irrespective of irrigation treatments. combined effect showed that the genotype blx-010014-9 under control condition produced the highest pods plant -1 (45.63) while the variety bari mosur-3 under drought condition produced the lowest pods plant -1 (22.34) (table 1). the number of pods in plant -1 were reduced under drought stressed over the irrigated condition might be due to reduction in flower fertilization and aggregate of flower shattering. the maximum 100-seed weight was recorded in genotype blx-010014-9 and ili-5143 (22.73 g and 22.38 g, respectively) under irrigated conditions and the lowest was in ili-5143, bari mosur-3 and bari mosur-2 (20.31, 0 0.2 0.4 0.6 0.8 1 1.2 1.4 b l x -0 1 0 0 1 4 -9 il i5 1 4 3 b a r i m o su r3 b a r i m o su r2 b l x -0 1 0 0 1 4 -9 il i5 1 4 3 b a r i m o su r3 b a r i m o su r2 control drought c h lo ro p h y ll ( m g g -1 f w ) chl a chl b chl (a+b) 100 ahmed et al. 20.11, 20.10 g, respectively) under without irrigation condition (table 1). irrespective of varietal difference seed yield plant -1 was reduced 39.0% under drought condition might be due to the reduction in number of pods plant -1 . this finding is corroborated with the results of pilbeam et al. (1992) who opined that grain yield of legume decreases greatly under drought condition due to the reduction of pods plant -1 . combined effect showed that blx-010014-9 under watery condition produced the highest seed yield (2.65 g plant -1 ) which was attributed by the maximum number of pods in plant -1 . the grain yield was decreased 29.0%, 29.8%, 49.0% and 52.0% for genotypes blx-010014-9, ili-5143, bari mosur-3 and bari mosur-2, respectively when those were given no irrigation. table 1. combined effect of irrigation regimes and genotypes on growth, yield and yield attributes of lentil during rabi 2017-2018 irrigation regimes genotype/variety plant height (cm) pods plant -1 (no.) seeds pod -1 (no.) 100-seed weight (g) yield plant -1 (g) control (with irrigation) blx-010014-9 33.65 45.63 1.96 22.73 2.65 ili-5143 38.62 42.13 1.56 22.38 2.52 bari mosur-3 31.20 26.39 1.52 21.35 2.21 bari mosur-2 30.25 35.26 1.31 21.31 2.13 drought (no irrigation) blx-010014-9 31.27 36.32 1.63 21.56 1.86 ili-5143 33.29 35.81 1.50 20.31 1.79 bari mosur-3 28.63 22.34 1.12 20.11 1.12 bari mosur-2 25.85 25.34 1.15 20.10 1.02 cv (%) 5.43 9.63 0.34 4.21 7.52 lsd(0.05) 11.3 22.3 ns 1.23 1.36 conclusion the results showed that large genetic variations were evident as drought tolerant trait. genotype blx010014-9 was found comparatively tolerant to drought stress as compared to others by showing the pertinent physiological indices like greater cat, pod, apx and lower mda. so, blx-010014-9 would be a potential genotype for cultivating in the drought prone areas and also be used for development of the drought tolerant variety/varieties of lentil. references ahmed, b., m.j. alam, m.a. hossain, m. sultana, m.n. islam and m.r. ali. 2016. study of selected lentil genotypes against drought. intl. j. appl. sci. 2(2): 95-99. arnon, d.i. 1994. copper enzymes in isolated chloroplasts. polyphenol oxidase in beta vulgaris. plant physiol. 24: 1-15. asfaw, a and m.w. blair. 2014. quantification of drought tolerance in ethiopian common bean varieties. agric. sci. 5: 124-139 chen, f., f. wang, f.b. wu, w.h. mao and g.p. zhang. 2010. modulation of exogenous glutathione in antioxidant defense system against cd stress in the two barley genotypes differing in cd tolerance. plant physiol. biochem. 48: 663-672. doi:10.1016/ j.plaphy.2010.05.001. pubmed: 20605723. chutipaijit, s., s. cha-um and k. sompornpailin. 2016. high contents of proline and anthocyanin increase protective response to salinity in oryza sativa l. spp. indica. aust. j. crop sci. 5: 1191-1198 yield and physiological indices of lentil genotypes 101 daryanto, s., l. wang and p.a. jacinthe. 2016. global synthesis of drought effects on maize and wheat production. plos one 11:e0156362 10.1371/ journal.pone. 0156362. das, k. and a.r. choudhury. 2016. reactive oxygen species (ros) and response of antioxidants as rosscavengers during environmental stress in plants. redox homeostasis managers in plants under environmental stresses, p.53. farooq m., n. gogoi, s. barthakur, b. baroowa, n. bharadwaj and s.s. alghamdi. 2016. drought stress in grain legumes during reproduction and grain filling. j. agron. crop sci. 203: 81–102. doi: 10.1111/jac.12169. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka 1215. 274p. gomez, a.a. and a.a. gomez. 1984. statistical procedure of agricultural research. second edition. john wiley and sons. new york. hameed, a., n. bibi, j. akhter and n. iqbal. 2011. differential changes in antioxidants, proteases, and lipid peroxidation in flag leaves of wheat genotypes under different levels of water deficit conditions. plant physiol. biochem. 49: 178-185. doi:https://doi.org/10.1016/ j.plaphy.2010.11.009. pubmed: 21159517. mafakheri, a., a. siosemardeh, b. bahramnejad, p.c. struik and e. sohrabi. 2010. effect of drought stress on yield, proline and chlorophyll contents in three chickpea cultivars. aust. j. crop sci. 4(8): 580585. nonami, h. 1998. plant water relations and control of cell elongation at low water potentials. j. plant res. 111: 373–382. doi: 10.1007/bf02507801. oweis, t., a. hachum and m. pala. 2004. lentil production under supplemental irrigation in a mediterranean environment. agric. water manag. 68(3): 251-265. pilbeam c.j., j.k. akatse, p.d. hebblethwaite and c.d. wright. 1992. yield production in two contrasting forms of spring-sown faba beans in relation to water supply. field crops res. 29: 73-287. rahimi, m.h., s. houshmand, m. khodambashi, b. shiran and s. mohammady. 2016. effect of drought stress on agro-morphological traits of lentil (lens culinaris medik.) recombinant inbred lines. bangladesh j. agril. res. 41(2): 207-219. saeedipour, s. 2012. effect of post-anthesis water deficit on yield and some physiological parameters on two wheat cultivars. afr. j. agric. res. 7: 3446-3452. taiz, l. and e. zeiger. 2006. plant physiology, 4th edn. sunderland, ma: sinauer associates inc publishers. wang, w.x., b. vinocur, o. shoseyov and a. altman. 2001. biotechnology of plant osmotic stress tolerance: physiological and molecular considerations. acta hortic. 560: 285–292. doi: 10.17660/actahortic.2001.560.54. wu, f.b., g.p. zhang and p. dominy. 2003. four barley genotypes respond differently to cadmium lipid peroxidation and activities of antioxidant capacity. environ. exp. bot. 50: 67-78. doi:10.1016/s0098-8472(02)00113-2. https://doi.org/10.1016/%20j.plaphy.2010.11.009 http://www.ncbi.nlm.nih.gov/pubmed/21159517 bangladesh agron. j. 2020, 23(2): 59-68 planting system effects on intercropping of gardenpea and sorghum a.a. begum* 1 m.a.k. mian 1 , s.m.a.h.m. kamal 2 , m.r.karim 1 , r.r.saha 3 and m.a. hossain 4 1 agronomy division, bari, gazipur-1701 2 rars, burirhat, rangpur, 3 oilseed research center-1701 4 ofrd, bari, gazipur-1701 *corresponding e-mail: luckyshamol6869@gmail.com (received: 30 september, 2020, accepted: 20 october, 2020) keywords: intercropping, sorghum, gardenpea, light availability, equivalent yield, bcr abstract the field experiment was conducted at agronomy research field, joydebpur and rars, burirhat, rangpur, bari during rabi season of 2018-2019 and 2019-2020 to find out suitable combination of sorghum and gardenpea intercropping for higher productivity and monetary advantage. treatments included in the experiment were: t1 = sorghum normal row (snr) + 1 row gardenpea (gp), t2 = snr + 2 rows gp, t3 = sorghum paired row (spr) + 2 rows gp, t4 = spr + 3 rows gp, t5 = spr + 4 rows gp, t6 = sole sorghum (60 cm  10 cm) and t7 = sole gp (30 cm  10 cm). light availability on gardenpea decreased with the increase of shade produced by sorghum canopy over the time up to 60 das. the lowest light availability on gardenpea was observed in t2 treatment and the highest was observed in sole gardenpea (t7) followed by t3 treatment in both the years. the maximum grain yield of sorghum was observed in t6 and it was decreased (6-10% in 2018-2019 and 1-12% in 2019-2020) at joydebpur and (5-11% in 2018-2019 and 6-14% in 2019-2020) at burirhat. the highest sorghum equivalent yield (sey) of 10.93 t ha -1 in 2018-2019 and 12.02 t ha -1 in 2019-2020 at joydebpur and 12.06 t ha -1 in 2018-2019 and 11.77 t ha -1 in 2019-2020 at burirhat and also the highest land equivalent ratio (ler) of 1.77 in 2018-2019 and 1.93 in 2019-2020 at joydebpur and 1.79 in 2018-2019 and 1.81 in 2019-2020 at burirhatwere observed in t5 treatment. the highest gross margin of tk.146600 ha -1 in 2018-2019 and tk.168400 ha -1 in 2019-2020 at joydebpur and tk. 169200 ha -1 in 2018-2019 and tk.163400 ha -1 in 2019-2020 at burirhat and also the benefit cost ratio (bcr) of 3.04 in 2018-2019 and 3.34 in 2019-2020 at joydebpur and 3.35 in 2018-2019 and 3.27 in 2019-2020 at burirhat were also found in the same treatment. the results revealed that sorghum paired row + 4 rows gardenpea might be agronomically feasible and economically profitable for sorghum + gardenpea intercropping system at joydebpur and burirhat region. introduction intercropping is an important tool for getting higher productivity per unit area of land (mahfuza et al., 2012). higher productivity from intercropping depends on judicious choice of component crops, suitable planting system or proportion of component crops (islam et al., 2006). sorghum is an unbranched and erect cereal crop grown with a wide spacing. several short duration and short stature vegetable like garden pea may be grown in association with sorghum. sorghum grain is as nutritious as other cereal grains; contains about 11% water, 340 k.cal of energy, 11.6% protein, 73% carbohydrate and 3% fat by weight (thimmaiah, 2002; taylor et al., 2006; yan et al., 2012). it is used as food, feed, fodder and fuel. sorghum's health benefits include more antioxidants, high protein, fiber and gluten free which make it a perfect dietary grain for all people, especially celiac patients. certain sorghum mailto:luckyshamol6869@gmail.com 60 begum et al. varieties are more easily digestible. on a field basis, sorghum yields have exceeded 11 t ha -1 with above average yields ranging from 7-9 t ha -1 where moisture is not a limiting factor. gardenpea is a very popular vegetable with rich in different nutrients. it contains about 68g water, 127 k.cal of energy, 7.4g protein, 24g carbohydrate and 26g calcium per 100 grams edible portion. generally legumes in association with non-legumes helps not only in utilization of the nitrogen being fixed in the current growing season, but also helps in residual nutrients build up of the soil (kakraliya et al., 2018). legumes enrich the soil with n and thus facilitate a better environment to subsequent crops for better growth and productivity (meena et al., 2015). legume cultivation releases up to seven times less ghgs per unit area than non-legume crops. legumes allow the sequestration of carbon (1.42 mg c ha -1 year -1 ) in soils and induce the conservation of fossil energy inputs in the system (kakraliya et al., 2018). farmers in the developing countries often demand for quick return from their crops, so they can get quick return by growing short duration vegetable crops with long duration crop like maize, sorghum etc. however, suitable intercrops, local food habit and market demands are important factors for getting higher benefit from intercropping. however, findings on profitability of sorghum + gardenpea intercropping under different planting systems are meagre in bangladesh. so, this experiment was conducted to find out suitable intercrop combination and planting system of sorghum and gardenpea intercropping for higher productivity and economic return. materials and methods the field experiment was conducted at the agronomy research field, joydebpur, gazipur and rars, burirhat, rangpur, bari during rabi season of 2018-2019 and 2019-2020. the soil was silty clay in texture at joydebpur (aez-28) and sandy loam at burirhat, rangpur (aez-3). treatments included in the experiment were: t1 = sorghum normal row (snr) + 1 row gardenpea (gp), t2 = snr + 2 rows gp, t3 = sorghum paired row (spr) + 2 rows gp, t4 = spr + 3 rows gp, t5 = spr + 4 rows gp, t6 = sole sorghum (60 cm  10 cm) and t7 = sole gp (30 cm  10 cm). the experiment was laid out in a randomized complete block design with three replications and the unit plot size was 4.8m  5m in both locations in both years. local sorghum variety (bsl-20) and bari sorghum-1 was used in 1 st and 2 nd year, respectively, and bari motorshuti-3 were used in the experiment for both locations in both years. seeds of sorghum and gardenpea were sown on same day. in 1 st year, seeds were sown on 22 november 2018 at joydebpur and 15 november 2018 at burirhat and in 2 nd year, seeds were sown on 24 november 2019 at joydebpur and 17 november 2019 at burirhat. seeds of both crops were treated with provax @ 3g kg -1 of seed in both locations. fertilizers were applied at the rate of 120-48-75-30-31 kg ha -1 of n, p, k, s, zn, b as urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate and boric acid for sole maize and intercrop. one third of n, whole amount of tsp, mop, gypsum, zinc sulphate and boric acid were applied as basal. remaining 2/3 n was top dressed at 25 and 45 days after sowing (das) of sorghum. in intercrop, extra n (40 kg ha -1 ) was applied in 2 splits at 20 and 35 das to gardenpea. sole gardenpea was fertilized at the rate of 4625-31-13-2.1 kg ha -1 of n, p, k, s and zn (frg, 2018). one third of n and all other fertilizers were applied as basal. rest n was applied in 2 splits at 20 and 35 das in both locations in both years. light availability or photosynthetically active radiation (par) was measured only at joydebpur location by par ceptometer (model – lp-80, accu par, decagon, usa). the par was measured at 5-day intervals from 25 to 60 das at around 11:30 am to 13:00 pm. four readings each of parinc and part were recorded at different spots of each plot. the proportion of intercepted par (parint) was calculated using the following equation and expressed in percentage (ahmed et al., 2010): light availability {parint (%)} = parinc part parinc 100 whrer, parinc = incident par, part = transmitted par, parint = intercepted par. https://news.uns.purdue.edu/html4ever/0004.hamaker.sorghum.html intercropping of gardenpea and sorghum 61 there was no facility to measure light availability in burirhat, rangpur. data on yield contributing characters of sorghum were taken from randomly selected 5 plants from each plot. yields of both the crops were taken from whole plot area in both locations. in 1 st year, sorghum was harvested on 4 april, 2019 and gardenpea was harvested 2 times on 20 and 28 january, 2019 and in 2 nd year, gardenpea was harvested 2 times on 25 and 31 january, 2020 and sorghum was harvested on 14 april, 2020 at joydebpur. on the other hand, in 1 st year, sorghum was harvested on 5 april, 2019 and gardenpea was harvested 2 times on 25 january and 2 february, 2019 and in 2 nd year, gardenpea was harvested 2 times on 2 and 10 february, 2019 and sorghum was harvested on 15 april, 2020 at burirhat. in both locations, sey was computed by converting yield of intercrops on the basis of prevailing market price of individual crop following the formula by bandyopadhyay (1984) as given below: sorghum equivalent yield = yis + (yigppgp)/ ps where, yis = yield of intercropped sorghum, yigp = yield of intercropped gardenpea, ps = market price of sorghum and pgp = market price of gardenpea. land equivalent ratio (ler) was obtained according to willey (1979) as follows: yield of sorghum as intercrop yield of gardenpea as intercrop yield of sorghum as sole crop yield of gardenpea as sole crop collected data of both the crops were analyzed statistically and the means were adjudged using lsd(0.05) test. economic analysis was also done considering local market price of harvested crops. results and discussion light availability availability of light on sorghum and gardenpea in intercropping was not markedly affected with each other in both years. because gardenpea was harvested at 55-60 das. at that time sorghum canopy could not produced much shade which might affect gardenpea. irrespective of treatments, availability of light on gardenpea canopy was almost 100% at earlier growth stage, 30 das of gardenpea and it decreased with the increase of shade produced by sorghum canopy over the time up to 60 das or up to harvest of gardenpea. however, among the intercropping treatments, the higher light availability on gardenpea was observed in t3 treatment followed by t4 throughout the growing period in both the years. the lower light availability on gardenpea was observed in snr + 2 rows gardenpea (t2) followed by t1 treatment and the lowest was observed at 60 das in the same treatment. among all treatments, the highest light availability was observed in sole gardenpea (t7) followed by t3 treatment in both the years. light availability on gardenpea canopy was more in the paired row than normal row of sorghum throughout the growing period and it was higher in 2019-2020 than that of 2018-2019 (fig.1 a.2018-2019 and b. 2019-2020). it might be due to higher number of tillers hill -1 in local variety used in 1 st year. fig. 1. light availability on gardenpea canopy in sorghum + gardenpea intercropping systems at joydebpur (a. 2018-2019 and b. 2019-2020). 0 20 40 60 80 100 120 30 40 50 60l ig h t a v a il a b il it y ( % ) days after sowing t1=snr +1 row gp t2=snr +2 row gp t3=spr +2 row gp t4=spr +3 row gp t5=spr +4 row gp t7=sole gp 0 20 40 60 80 100 120 30 40 50 60l ig h t a v a il a b il it y ( % ) days after sowing t1=snr +1 row gp t2=snr +2 row gp t3=spr +2 row gp + ler = a. 2018-2019 b. 2019-2020 62 begum et al. yield and yield components of sorghum grain yield and yield contributing characters of sorghum at both locations during rabi of 2018-2019 and 2019-2020 have been presented in table 1 and table 2. plant height, yield contributing characters (number of panicles hill -1 , panicle length, number of grains panicle -1 , 1000-grain weight) and grain yield of sorghum were not significantly differed among the treatments in both years in both locations. at joydebpur the highest grain yield (3.87 t ha -1 in 1 st year and 4.41 t ha -1 in 2 nd year) were recorded in sole sorghum due to no intercrop competition for growth resources like light, nutrients, moisture and space in sole cropping. table 1. plant height, panicle hill -1 , panicle length and grains panicle -1 of sorghum in sorghum + gardenpea intercropping during rabi of 2019-2020 (joydebpur and burirhat, rangpur) treatments plant height (cm) panicles hill-1 (no.) panicle length (cm) grains panicle-1 (no.) 20182019 20192020 20182019 20192020 20182019 20192020 20182019 20192020 joydebpur t1 185.3 134 5.3 2.1 18.40 16.6 784 1541 t2 184.0 136 5.3 2.1 18.87 16.5 756 1543 t3 192.0 136 5.0 2.1 18.67 16.8 723 1591 t4 186.7 137 5.3 2.1 19.13 16.6 794 1597 t5 185.7 136 5.7 2.2 19.80 16.8 742 1604 t6 193.0 137 5.3 2.3 19.60 17.4 814 1615 lsd(0.05) ns ns ns ns ns ns ns ns cv (%) 7.80 3.82 6.05 8.63 5.70 6.88 10.37 6.13 burirhat, rangpur t1 185.3 132 6.0 1.5 18.40 17.97 788 1570 t2 187.7 135 6.0 1.0 18.87 17.83 759 1530 t3 184.0 137 5.7 1.8 18.67 17.85 766 1582 t4 183.3 128 5.7 1.1 19.13 18.15 798 1564 t5 187.0 129 6.3 1.3 19.80 18.39 758 1574 t6 190.3 139 6.7 2.6 19.60 18.72 818 1602 lsd(0.05) ns ns ns ns ns ns ns ns cv (%) 5.93 5.18 7.90 8.63 6.30 5.41 8.63 5.94 this corroborates with the findings of begum et al. (2016). among the intercropping system, t5 (spr + 4 rows gp) gave the highest grain yield (3.64 t ha -1 in 1 st year and 4.39 t ha -1 in 2 nd year) followed by t4. the lowest grain yield (3.47 t ha -1 in 1 st year and 3.90 t ha -1 in 2 nd year) was recorded in snr + 2 rows gp (t2). however, grain yield of sorghum in different treatments were attributed by the cumulative effect of yield components. at burirhat, rangpur the highest grain yield (3.92 t ha -1 in 1 st year and 4.46 t ha -1 in 2 nd year) were recorded in sole sorghum due to no intercrop competition for growth resources like light, nutrients, moisture and space in sole cropping. this corroborates with the findings of begum et al. (2016). among the intercropping system, t5 (spr + 4 rows gp) gave the highest grain yield (3.71 t ha -1 in 1 st year and 4.20 t ha -1 in 2 nd year) followed by t4. the lowest grain yield (3.49 t ha -1 in 1 st year and 3.83 t ha -1 in 2 nd year) was recorded in snr + 1 row gp (t1). however, grain yield of sorghum in different treatments were attributed by the cumulative effect of yield components. intercropping of gardenpea and sorghum 63 grain yield of sorghum in 2 nd year was higher than that of in 1 st year in both locations. it might be due to local variety of sorghum was used in 1 st year and in 2 nd year, hyv bari sorghum-1 was used in both locations. table 2. 1000-grain weight and grain yield of sorghum in sorghum + gardenpea intercropping during rabi of 2019-2020 (joydebpur and burirhat, rangpur) treatments 1000-grain wt. (g) grain yield ( t ha-1) yield decrease over sole sorghum (%) 2018-2019 2019-2020 2018-2019 2019-2020 2018-2019 2019-2020 joydebpur t1 16.67 33.13 3.54 3.94 9 11 t2 16.93 32.13 3.47 3.90 10 12 t3 16.93 33.33 3.52 3.91 9 11 t4 16.60 33.73 3.54 4.12 9 7 t5 16.67 33.80 3.64 4.39 6 1 t6 17.07 33.32 3.87 4.41 lsd (0.05) ns ns ns ns cv (%) 5.50 5.31 5.84 9.64 burirhat, rangpur t1 16.80 32.02 3.49 3.83 11 14 t2 17.07 32.35 3.65 3.98 7 11 t3 16.07 31.93 3.58 4.03 9 10 t4 16.73 32.47 3.65 4.01 7 10 t5 16.93 32.56 3.71 4.20 5 6 t6 17.73 33.03 3.92 4.46 lsd (0.05) ns ns ns ns cv (%) 4.57 6.22 5.77 7.13 t1 = sorghum normal row (snr) + 1 row gardenpea (gp), t2 = snr + 2 rows gp, t3 = sorghum paired row (spr) + 2 rows gp, t4 = spr + 3 rows gp, t5 = spr + 4 rows gp, t6 = sole sorghum (60 cm  10 cm) and t7 = sole gp (30 cm  10 cm) yield of gardenpea yield and yield components of gardenpea in different sorghum + gardenpea intercropping in both the locations (joydebpur and burirhat, rangpur) during rabi of 2018-2019 and 2019-2020 have been presented in (table 3). number of plants m -2 and green pod yield of gardenpea were significantly influenced by different planting systems in both year and in both locations. at joydebpur the highest number of plants m -2 was observed in sole gardenpea (28 m -2 in 1 st year and 26 m -2 in 2 nd year) and the lowest was observed in t1 treatment (11 m -2 in 1 st year and 10 m -2 in 2 nd year) due to variation of planting system. the highest green pod yield (8.84 t ha -1 in 1 st year and 8.18 t ha -1 in 2 nd year) was found in sole gardenpea due to higher plant population per unit area. there was no intercrop competition for growth resources in sole cropping of gardenpea. among the intercrop treatments, the highest green pod yield (7.29 t ha -1 in 1 st year and 7.63 t ha -1 in 2 nd year) was observed in t5. the lowest green pod yield (3.89 t ha -1 ) was observed in t3 in 1 st year and in t1 in 2 nd year (4.67 t ha -1 ) due to the lowest number of plant population of gardenpea per unit area. at burirhat more or less similar trend was observed in burirhat. the highest number of plants m -2 was observed in sole gardenpea (30 m -2 in 1 st year and 27 m -2 in 2 nd year) and the lowest was observed in t3 treatment (12 m -2 in both year) due to variation of planting system. the highest green pod yield (9.95 t ha -1 in 1 st year and 8.68 t ha -1 in 2 nd year) was found in sole gardenpea due to higher plant population per unit area. there was no intercrop competition for growth resources in sole cropping of gardenpea. among 64 begum et al. the intercrop treatments, the highest green pod yield (8.35 t ha -1 in 1 st year and 7.57 t ha -1 in 2 nd year) was observed in t5. the lowest green pod yield (4.68 t ha -1 ) was observed in t3 in 1 st year and in t1 in 2 nd year (5.02 t ha -1 ) due to the lowest number of plant population of gardenpea per unit area. table 3. plant height, yield and yield components of gardenpea in sorghum + gardenpea intercropping during rabi of 2019-2020 (joydebpur and burirhat, rangpur) treatments plant height (cm) plants m-2 (no.) pod plant-1 (no.) seed pod-1 (no.) green pod yield (t ha-1) 20182019 20192020 20182019 20192020 20182019 20192020 20182019 20192020 20182019 20192020 joydebpur t1 50.33 48.5 12 10 6.33 6.4 5.07 5.07 4.76 4.67 t2 51.40 51.4 21 23 6.27 6.4 5.13 5.13 6.44 7.62 t3 50.87 48.5 11 13 7.13 7.2 5.07 5.07 3.89 4.72 t4 51.87 50.5 14 15 6.73 6.8 5.13 5.13 6.25 6.92 t5 52.67 51.3 21 23 6.53 6.6 5.20 5.20 7.29 7.63 t7 49.47 48.4 28 26 7.33 7.4 6.87 6.87 8.84 8.18 lsd(0.05) ns ns 4.06 5.54 ns ns ns ns 1.05 2.47 cv (%) 10.20 5.94 8.35 12.20 13.30 8.77 6.67 6.67 6.60 14.42 burirhat, rangpur t1 64.43 57.8 14 14 8.1 8.20 7.90 5.67 5.80 5.15 t2 63.63 55.7 25 23 8.0 7.87 7.63 5.00 7.54 6.48 t3 64.83 59.5 12 12 8.9 8.73 7.87 5.20 4.68 5.02 t4 64.23 56.3 18 16 8.5 8.07 8.07 5.13 7.25 6.62 t5 64.43 59.4 24 21 8.3 8.33 8.03 5.73 8.35 7.57 t7 61.83 58.5 30 27 9.1 9.20 8.10 6.07 9.95 8.68 lsd(0.05) ns ns 4.81 6.83 ns ns ns ns 0.58 0.86 cv (%) 8.90 3.06 9.09 14.01 12.67 10.68 6.89 9.93 4.39 4.59 t1= (snr) +1 row gp, t2=snr +2 row gp, t3= sorghum paired row (spr) +2 row gp, t4=spr +3 row gp, t5= spr +4 row gp, t6=sole sorghum (60 cm  10 cm) and t7= sole gp (30 cm  10 cm) evaluation of intercrop productivity sorghum and gardenpea intercrop productivity was evaluated on the basis of land equivalent ratio and sorghum equivalent yield (bandyophadhyay, 1984). land equivalent ratio (ler) and sorghum equivalent yield (sey) of different treatment in both locations have been presented in table 4. the ler values were found more than unity in all the intercropping systems indicated that land was more efficiently utilized under intercropping than sole cropping of sorghum and gardenpea. at joydebpur the ler values in the intercrops ranged from 1.35 to 1.77 in 1 st year and 1.46 to 1.93 in 2 nd year which indicated that land utilization increased 35 to 77% in 1 st year and 46 to 93% in 2 nd year by intercropping. the highest ler (1.77 and 1.93 in 1 st and 2 nd year, respectively) was observed in spr + 4 rows gp (t5). sey of all the intercropping systems was higher than sole sorghum indicating higher productivity of intercropping than sole sorghum. in intercropping, the highest sorghum equivalent yield (10.93 and 12.02 t ha -1 in 1 st and 2 nd year, respectively) was observed in t5 treatment (spr + 4 rows gp) which was 182 and 173% higher than sole sorghum in 1 st and 2 nd year, respectively. the lowest sey was observed in t6 (sole sorghum) in both years. at burirhat similar trend was observed in burirhat. the ler values in the intercrops ranged from 1.38 to 1.79 in 1 st year 1.43 to 1.80 in 2 nd year and which indicated that land utilization increased 38 to 79% in 1 st year and 43 to 80% in 2 nd year by intercropping. the highest ler (1.79 and 1.80 in 1 st and 2 nd year, intercropping of gardenpea and sorghum 65 respectively) was observed in spr + 4 rows gp (t5). sey of all the intercropping systems was higher than sole sorghum indicating higher productivity of intercropping than sole sorghum. in intercropping, the highest sorghum equivalent yield (12.06 and 11.77 t ha -1 in 1 st and 2 nd year, respectively) was observed in t5 treatment (spr + 4 rows gp) which was 208 and 164% higher than sole sorghum in 1 st and 2 nd year, respectively. the lowest sey was observed in t6 (sole sorghum) in both years. table 4. land equivalent ratio and sorghum equivalent yield as influenced by different planting systems in sorghum + gardenpea intercropping during rabi of 2019-2020 (joydebpur and rangpur) treatments ler sey (t ha-1) % increased of sey over sole sorghum 2018-2019 2019-2020 2018-2019 2019-2020 2018-2019 2019-2020 joydebpur t1 1.44 1.46 8.30 8.61 115 95 t2 1.64 1.82 9.91 11.52 156 161 t3 1.35 1.46 7.41 8.63 92 96 t4 1.62 1.78 9.79 11.04 153 150 t5 1.77 1.93 10.93 12.02 182 173 t6 1.00 1.00 3.87 4.41 t7 1.00 1.00 8.84 8.18 burirhat t1 1.47 1.45 9.29 8.98 137 101 t2 1.69 1.64 11.19 10.46 186 135 t3 1.38 1.48 8.26 9.05 111 103 t4 1.66 1.66 10.90 10.63 178 138 t5 1.79 1.81 12.06 11.77 208 164 t6 1.00 1.00 3.92 4.46 t7 1.00 1.00 9.95 8.68 t1 = sorghum normal row (snr) + 1 row gardenpea (gp), t2 = snr + 2 rows gp, t3 = sorghum paired row (spr) + 2 rows gp, t4 = spr + 3 rows gp, t5 = spr + 4 rows gp, t6 = sole sorghum (60 cm  10 cm) and t7 = sole gp (30 cm  10 cm) economic performance cost and return analysis is an important tool to evaluate the economic feasibility of intercropping system and monetary advantage was evaluated according to shah et al. (1991). benefit cost analysis of sorghum + gardenpea intercropping systems in both locations have been presented in table 5. gross return and bcr depends on equivalent yield. at joydebpur among intercropping treatments, the highest gross return (tk. 218600 ha -1 and tk. 240400 ha -1 in 1 st and 2 nd year, respectively) was observed in t5 treatment (sorghum paired row + 4 rows gardenpea) and it was close to t2 owing to higher sey in both years. the gross margin also followed the similar trend of gross return. cost of production differed among the treatments. the highest cost of production was recorded in t5 treatment which was close to t2 (snr + 2 rows gp) due to involvement of higher costs (higher amount of gardenpea seed and labor cost) in both years. among intercropping treatments, the highest benefit cost ratio (3.04 and 3.34 in 1 st and 2 nd year, respectively) was obtained from t5 (snr + 4 rows gp) treatment. this result has been supported by the findings of islam et al. (2013). at burirhat among intercropping treatments, the highest gross return (tk. 241200 ha -1 and tk. 235400 ha -1 in 1 st and 2 nd year, respectively) was observed in t5 treatment (sorghum paired row + 4 rows gardenpea) and 66 begum et al. it was close to t2 owing to higher sey in both years. the gross margin also followed the similar trend of gross return. table 5. benefit cost analysis of sorghum + gardenpea intercropping under different planting system during rabi of 2018-2019 and 2019-2020 (joydebpur and burirhat, rangpur) gross return (tk. ha-1) cost of cultivation (tk. ha-1) gross margin (tk. ha-1) bcr 2018-2019 2019-2020 2018-2019 2019-2020 2018-2019 2019-2020 2018-2019 2019-2020 joydebpur t1 166000 172200 66000 66000 100000 106200 2.52 2.61 t2 198200 230400 73500 73500 124700 156900 2.70 3.13 t3 148200 172600 66000 66000 82200 106600 2.25 2.62 t4 195800 220800 70500 70500 125300 150300 2.78 3.13 t5 218600 240400 72000 72000 146600 168400 3.04 3.34 t6 77400 88200 52500 52500 24900 35700 1.47 1.68 t7 176800 163600 61500 61500 115300 102100 2.87 2.66 burirhat t1 185800 179600 66000 66000 119800 113600 2.82 2.72 t2 223800 209200 73500 73500 150300 135700 3.04 2.85 t3 165200 181000 66000 66000 99200 115000 2.50 2.74 t4 218000 212600 70500 70500 147500 142100 3.09 3.02 t5 241200 235400 72000 72000 169200 163400 3.35 3.27 t6 78400 89200 52500 52500 25900 36700 1.49 1.70 t7 199000 173600 61500 61500 137500 112100 3.24 2.82 t1= (snr) +1 row gp, t2=snr +2 rows gp, t3= sorghum paired row (spr) +2 rows gp, t4=spr +3 rows gp, t5= spr +4 rows gp, t6=sole sorghum (60 cm  10 cm) and t7= sole gp (30 cm  10 cm) market price (tk kg -1 ): sorghum = 20, gardenpea = 20 in both locations cost of production differed among the treatments. the highest cost of production was recorded in t5 treatment which was close to t2 (snr + 2 rows gp) due to involvement of higher costs (higher amount of gardenpea seed and labor cost) in both years. among intercropping treatments, the highest benefit cost ratio (3.35 and 3.27 in 1 st and 2 nd year, respectively) was obtained from t5 (snr + 4 rows gp) treatment. this result has been supported by the findings of islam et al. (2013). conclusion result revealed that all the intercropping showed better productivity and profitability than growing sole sorghum. sorghum paired row + 4 rows gardenpea intercropping was found agronomically feasible and economically profitable in joydebpur and rangpur. references ahmed, f., m.n. islam, m.t. rahman, m.a. jahan and m.s.a. khan. 2010. leaf area index, radiation interception, dry matter production and grain yield of hybrid maize as influenced by plant spacing. bangladesh agron. j. 13(1 & 2): 51-58. bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. begum, a.a., m.s.u. bhuiya, s.m.a. hossain, amina khatun and s.k. das. 2016. effect of planting system of potato and plant density of maize on productivity of potatohybrid maize intercropping system. bangladesh j. agril. res. 41(3): 397-409. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council (barc), farmgate, dhaka 1215. 223p. intercropping of gardenpea and sorghum 67 islam, m.n., m. akhteruzzaman and m.s. alom. 2013. split application of inorganic fertilizers in potato (solanum tuberosum l.)-hybrid maize (zea mays l.) intercropping system. bangladesh j. agril. res. 38(3): 447-453. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effects on the physiological attributes and productivity of maize–bushbean intercropping systems. bangladesh j. agril. res. 31(3): 353-364. kakraliya, s.k., u. singh, a. bohra and k.k. chaudhary. 2018. nitrogen and legumes: a metaanalysis. in: legumes for soil health and sustanable management. 277-314pp. http://researchgate.net/publication/326227137-nitrogen-and-legumes-a-meta-analysis. mahfuza, s.n., m.n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping different vegetables and spices with pointed gourd. j. expt. biosci. 3(1): 77-82. meena, r.s., r.s.yadav, h. meena, s. kumar, y.k. meena and a. singh 2015. towards the current need to enhance legume productivity and soil sustainability worldwide: a book review. j clean prod. 104: 513–515 shah, n.h., p.k. koul, b.a. khanday and d. kachrov. 1991. production potential and monetary advantage index of maize intercropped with different grain legumes. indian j. agron. 36(1): 23-28. taylor, j., t.j. schober and s.r. bean. 2006. novel food and work at sebnie and merse mengesha /arch. agr. environ. sci. 3(2): 180-186. thimmaiah, s.k. 2002. effect of salinity on biochemical composition of sorghum (sorghum bicolor l.) seeds. indian j. agril. biochem. 15(1-2): 13-15. willey, r.w. 1979. intercropping: its performance and research needs. part i. competition and yield advantages. field crops abs. 32: 1-10. yan, k., p. chen, h. shao, s. zhao, l. zhang, g. xu and j. sun. 2012. responses of photosynthesis and photosystem ii to higher temperature and salt stress in sorghum. j. agron. crop sci. 198(3): 218 -225. https://dx.doi.org/10.1111/j.1439-037x.2011.00498.x bangladesh agron. j. 2020, 23(2): 103-109 organic amendment on soil quality and yield performance of dry direct seeded boro rice m.m. rahman 1 and m. uddin 2 1 professor and 2 post-graduate student, department of agronomy, bangladesh agricultural university, mymensingh corresponding email: rahmanag63@gmail.com (received: 10 october, 2020, accepted: 03 november, 2020) keywords: trichocompost, vermicompost, mustard oil cake, water saving, boro rice, organic matter abstract an experiment was conducted at khitrokashipur, durgapur, rajshahi during march to june 2018 to study the effect of organic amendment on soil quality and yield performance of dry direct seeded boro rice var. brri dhan28. the treatments were trichocompost (tc), vermicompost (vc), mustard oil cake (moc), trichocompost + mustard oil cake (tc+moc), vermicompost + mustard oil cake (vc + moc), and no amendment control. the experiment was laid out in a randomized complete block design with three replications. trichocompost and vermicompost were applied @ 3 t ha -1 , while mustard oil cake was used @ 0.5 t ha -1 . the results revealed that trichocompost and vermicompost fertilization exerted significant influence on yield performance of brri dhan28 in boro season. the treatment trichocompost (t1) @ 5 t ha -1 produced the highest grain yield (5.95 t ha -1 ), while the mustard oil cake (t3) @ 0.5 t ha -1 the highest effective tillers hill -1 (15.33), though the highest straw yield (5.46 t ha -1 ) was produced in the treatment vc + moc (t5). in case of soil properties, trichocompost (t1) @ 3 t ha -1 and mustard oil cake (t3) @ 0.5 t ha -1 improved soil organic matter content, while trichocompost (t1) @ 3 t ha -1 and vermicompost (t2) @ 0.5 t ha -1 improved phosphorus and potassium content. field capacity was greatly influenced by trichocompost (t1) @ 3 t ha -1 and vermicompost + mustard oil cake (t5). soils with trichocompost (t1) @ 3 tha -1 showed the highest bulk density. it was concluded that organic amendment greatly improved the yield performance of brri dhan28 and also soil physical and chemical properties under dry direct seeded boro rice cultivation system. introduction rice (oryza sativa l.) contributes 95% to food production in bangladesh. about 77% of cropped area of bangladesh is used for rice production, with the annual production of 37.36 million tons from 11.68 million ha of land (ais, 2020). the rice production in the country has been increased by 3.4 folds over the last four decades. in bangladesh, more than 55.0 million tons of rice will be required by the year 2050 when population of bangladesh will be 233.3 million (basak, 2009). the possibility of expanding the area under rice in near future is limited. the major challenges to achieve this gain are accompanied with less water, labor shortage, and negative impact of chemicals use, especially for attaining long-term sustainability. the rice production with less water and labor can be achieved by adopting different climate smart technologies, such as dry direct seeding, organic amendment and cropping pattern renovation. direct seeding of rice refers to the process of establishing the rice crop from seeds directly sown in the field rather than by transplanting of seedlings from the nursery. there are three principal methods of direct seeding of rice (dsr): dry seeding (sowing dry seeds into dry soil), wet seeding (sowing pregerminated seeds on wet puddle soils) and water seeding (seeds sown into standing water). dry seeding mailto:rahmanag63@gmail.com 104 rahman et al. has been the principal method of rice establishment since the 1950s in developing countries (pandey and velasco, 2005). in the traditional transplanting system (tpr), puddling creates a hard pan below the plough-zone and reduces soil permeability. it leads to high losses of water through puddling, surface evaporation and percolation. water resources, both surface and underground are shrinking and water has become a limiting factor in rice production (rahman, 2019). in practice, boro rice uses about 70% of total water used in agriculture. therefore, technologies and practices need to be in place for sustaining boro rice production, while increasing cropping intensity with minimal water input especially in the drought prone areas. dry seeding allows cultivation of boro rice with less than 50% irrigation water compared with that required in puddle transplanted method (rahman et al., 2012: rahman and masood, 2014, rahman, 2019). the adoption of a direct-seeded method for lowland rice culture would significantly decreases costs of rice production (rahman and masood, 2014). as this cultivation system is done in dry land, organic matter decreases rapidly and therefore, it needs to increase organic matter status in soil. direct seeding is done after dry cultivation, and controlled irrigation is provided to keep the soil at field capacity. however, standing water is maintained for a very short period of time from panicle initiation to heading or grain filling (rahman et al., 2020). organic amendment through trichocompost, vermicompost and mustard oil cake increases organic matter content and water holding capacity of soil as well as allows more infiltration to increase water retention capacity of the soil (minasny and mcbratney, 2018). t. aman – mustard – dds boro rice is considered as one of the most promising cropping patterns for increasing farm productivity and farmers income (rahman, 2018). however, it is important to adopt management practices that improve the system productivity and soil health as well. therefore, the present study was undertaken to evaluate the effect of organic amendment on soil quality and yield performance of dry seeded boro rice under t. aman rice – mustard dds boro rice cropping pattern. materials and methods site and soil the experiment was conducted at farmers’ field in khitrokashipur village of durgapur upazilla in rajshahi district. the field is located at 24°75 n latitude, 90°50 e longitude and at an altitude of 18 m. the area falls under high barind tract agro-ecological zone (aez-26) having non–calcareous dark grey floodplain soil. the land was a medium high with moderate drainage facilities. the soil was silt loam having ph value of 6.5. the particle density and bulk density values of soil were 2.60 and 1.35 g cc -1 , respectively. soil contained 1.78% organic matter, 0.14% total n, 1.98 µ g -1 available p, 0.10 meq 100g -1 exchangeable k and 4.56 µg g -1 available s. the experimental area falls under the sub-tropical climate characterized by its heavy rainfall during kharif season (april to september) and scanty rainfall during rabi season (october to march). experimental treatments and design the study included six combinations of three organic manures viz., (i) trichocompost (tc) @ 3 t ha -1 (t1); (ii) vermicompost (vc) @ 3 t ha -1 (t2); (iii) mustard oil cake (moc) @ 0.5 t ha -1 (t3); (iv) =trichocompost + mustard oil cake @ 0.5 t ha -1 (t4); (v) vermicompost + mustard oil cake @ 0.5 t ha -1 (t5) and (vi) control (no organic matter applied, t0) in a randomized complete block design (rcbd) with three replications. the size of each unit plot was 3m x 2.5m. crop management the experiment was done under t. aman rice – mustard dds boro cropping pattern. twenty five days old seedling of brri dhan57 was transplanted in well puddled land at 25 cm x 15 cm spacing organic amendment on soil quality and yield performance of boro rice 105 with three seedling hill -1 on 12 july 2017. the crop was cultivated with recommended agronomic management practices as and when needed. the aman rice was harvested on 5 november 2017. then mustard var. bari sharisha14 was sown on 27 november and harvested on 20 february 2018. after harvest of mustard, rice var. brri dhan28 was grown following the standard practices for dry direct seeded system. seeds were sown in furrows with 5 seeds hill -1 on 16 march 2018 under dry direct seeded system. the land was fertilized with urea, triple super phosphate, muriate of potash and gypsum at the rate of 375 kg, 60 kg, 92 kg and 70 kg ha -1 , respectively. the whole amount of triple super phosphate, muriate of potash and gypsum was applied at the time of final land preparation. urea was applied in three equal splits at 21, 42 and 63 days after sowing (das). pre-emergence herbicide (panida 33ec) was applied for weed control @ 50 ml 10 l -1 of water on 17 march 2018. intercultural operations were done for maintaining the normal growth and development of the crop. weeding was done twice by hand pulling at 21 and 41das. irrigation was provided only to maintain the field at moist soil condition for successful crop growth and development. during the whole crop period, only four irrigations were given at 22, 43, 65 and 73 das. the crop was infested by thrips which was controlled by applying diazinon @ 35 ml 10 l -1 of water. the crop was harvested at full maturity on 23 june 2018 from central 1.8 m × 1.5 m area of each plot for recording yields of grain and straw. grains and straw were sun dried and cleaned. grain yields was adjusted to 14% moisture and converted to ton per hectare. data recording data on various plant characters like plant height, tiller production and yield contributing characters were recorded from randomly collected five hills plot -1 before plot harvest. after harvest of boro rice, soil sample was collected from 0 to 15 cm depth from the experimental field by iron core to record soil related datasoil ph, bulk density, organic matter content (%), field capacity (%), phosphorus and potassium content. after processing the soil was taken to the humboldt soil lab of the department of soil science, bau. soil ph was determined by glass electrode ph meter. the soil phosphorus was determined by olsen method (horta and torrent, 2007). soil organic matter content was determined by wet oxidation method. for determining field capacity (%) collected soils with cores were soaked with water for about 48 hours. after that soil was allowed to air dry about 72 hours and weighted. the field capacity (%) was determined using the following formulae. field capacity (%) = x 100 statistical analysis the collected data were compiled and tabulated in proper form and were subjected to statistical analysis with the help of a computer package programme statistix 10 and mean differences were adjudged by duncan’s multiple range test. results and discussion crop yield and yield parameters organic amendment had significant effect on grain and straw yields, number of effective and noneffective tillers hill -1 but insignificant on plant height, number of total tillers hill -1 , panicle length, number of grains panicle -1 , number of sterile spikelets panicle -1 and 1000-grain weight. data presented in table 1 revealed that the maximum plant height (107.21 cm) was observed in control treatment (t0) and the shortest (104.58 cm) in tc + moc @ 0.5 t ha -1 treatment (t4). the highest number of effective tillers hill -1 (15.33) and non-effective tillers (3.67) was obtained with the treatment moc @ 0.5ton ha -1 (t3). the lowest number of effective tillers hill -1 (12.33) and non-effective tillers was found in the 106 rahman et al. control treatment (table 1). the highest number of grains plant -1 (85.33) was obtained from vc @ 3 ton ha -1 (t2), and the lowest one (68.300) was observed with control. the highest number of sterile spikelet (26.66) was obtained from tc + moc (t4), while the lowest (23.00) in control (table 2). numerically, the highest 1000-grain weight (20.75 g) was obtained from vc + moc (t5) and the lowest weight (19.15 g) was obtained from moc (t3). table 1. effect of organic amendment on plant height and tiller production of dry direct seeded boro rice var. brri dhan28 treatments plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) non effective tillers hill-1 (no.) panicle length (cm) t0 107.15 12.67 12.33b 2.33b 23.33 t1 105.00 14.67 13.33ab 2.33b 24.03 t2 105.83 15.67 13.00ab 2.67ab 23.03 t3 105.67 16.67 15.33a 3.67a 23.70 t4 104.58 16.67 15.00ab 3.00ab 27.73 t5 106.17 14.67 14.00ab 2.67ab 23.70 lsd (0.05 ) ns ns 2.92 1.23 ns cv (%) 1.63 12.10 7.47 15.65 3.81 in a column, figures with same letter(s) or without letter do not differ significantly t0= control (no organic matter used), t1=trico-compost (tc) @ 3 t ha -1 used, t2 = vermicompost @ ha -1 , t3= mustard oil cake @ 0.5 ha -1 , t4= trichocompost + mustard oil cake , t5 = vermicompost + mustard oil cake table 2. effect of organic amendment on yield and related attributes of dry direct seeded boro rice var. brridhan28 treatments grains panicle-1 (no.) sterile spikelet panicle-1 (no.) weight of 1000-grain (g) grain yield ha-1 (ton) straw yield ha-1 (ton) t0 68.30 23.00 20.19 4.25b 4.68b t1 72.77 26.00 19.89 5.95a 5.41a t2 85.33 26.33 20.08 5.57a 5.07ab t3 77.80 24.33 19.15 5.25ab 5.37a t4 73.13 26.67 20.06 5.61a 5.38a t5 73.07 25.00 20.75 5.48ab 5.46a cv (%) 8.94 11.93 4.69 8.33 4.41 lsd (0.05) ns ns ns 1.26 0.65 in a column, figures with same letter(s) or without letter do not differ significantly, whereas figures with dissimilar letter(s) differ significantly t0= control (no organic matter used), t1=trico-compost (tc) @ 3 t ha -1 used, t2= vermicompost @ ha -1 , t3=mustard oil cake @ 0.5 ha -1 , t4= trichocompost+mustard oil cake , t5=vermicompost+mustard oil cake the maximum grain yield (5.95 t ha -1 ) was observed in the treatment tc @ 5 ton ha -1 (t1), while the lowest one (4.25 t ha -1 ) in control (t0). the result revealed that yield improvement was obtained with the organic amendment with tricho-compost alone or in combination with mustard oil cake. the grain yield obtained with tc was similar with those of t2 and t4. however, the highest straw yield (5.66tha 1 ) was observed in the treatment vc + moc (t5), while the lowest one (4.68 t ha -1 ) in control treatment. thus, the result clearly showed that the yield improvement of direct seeded boro rice was possible through organic amendment with trichocompost or vermicompost @ 3 t ha -1 . benbi et al. (1998) also found that farm yard manure in combination with npk chemical fertilizers resulted in higher soil organic carbon concentration and enhanced crop growth along with higher root biomass production. organic matter amendment is effective in increasing rice yield. organic amendment with compost along with application of chemical fertilizers increased the biomass and grain yields of crops (saleque et al., 2004, sarwar et al., 2007). several studies also reported that long – term organic amendment increased rice yield in rice – wheat system (shamsuhddin and fauziah, 2010; mitran and mani, 2017). organic amendment on soil quality and yield performance of boro rice 107 mitran and mani (2017) reported that the long-term application of inorganic fertilizer in conjunction with fym, ps, and gm had a significant effect on maintaining positive yield trend in case of rice under such rice – wheat system over control. soil physical and chemical properties organic amendment did not have significant effect on ph, organic matter content, bulk density, field capacity, phosphorus and potassium content of soil of the experimental field after harvest of the dry direct seeded rice (table 3). however, the lowest ph of soil (5.8) was found in control (t0) and the highest (6.02) was observed in the treatment tricho-compost (t1) @ 3 t ha -1 . the highest om of soil (1.08) was found with mustard oil cake (t3) @ 0.3 t ha -1 and the lowest (0.84) was with vermicompost treatment @ 3 t ha -1 (t2). the highest bd of soil (1.43) was determined in the treatment trichocompost @ 3 t ha -1 (t1) and the lowest (1.32) was in vermicompost + moc @ 0.5 t ha -1 (t5). however, the highest fc of soil (33.83) was found in vermicompost + mustard oil cake @ 0.5 tha -1 (t5) treatment and the lowest (31.20) in trichocompost @ 3 t ha -1 treatment (t1). phosphorus was the highest (24.9) in the treatment trichocompost @ 3 t ha -1 (t1) and lowest (16.23) in vermicompost treatment @ 0.3 t ha -1 (t2). the treatment vermi-compost @ 3 t ha -1 (t2) had the highest k of soil (0.17), while the lowest (0.15) in vermicompost + moc @ 0.5 t ha -1 treatment (t5). it was noted that soil ph and soil organic matter were consistently higher in t4 and t5 than those in other treatments. on the other hand, soil bulk density, field capacity and soil phosphorus content were consistently higher in t4 and t3 than those in other treatments. however, soil potassium was consistently high in t4 and t1 than the other treatments. earlier report indicated that integrated nutrient management through the combined use of inorganic and organic fertilizers increased crop yield and improved n and k use efficiency (ryan et al., 2017). it was also disclosed that the efficiency of fertilizer p use could possibly be increased by recycling of p from crop residues, and organic and mineral fertilizers (hedge and dwivedi, 1993). integrated use of organic manures and fertilizers not only improved the efficiency of p (vats et al., 2001) but also significantly increased the availability of p. mitran and mani (2017) observed that long – term organic amendment increased p content in rice soil. organic amendment also improved water use efficiency (wue) of crop plants by improving soil water holding capacity as reported by shehzadi et al. (2017)). a high wue is a good indicator of a crop to cope with soil water deficit and provides a greater opportunity for increasing grain yield (zhou et al., 2017). table 3. effect of organic amendment on soil physical and chemical characteristics after growing direct seeded boro rice in a rice-mustard-direct seeded rice system treatments ph organic matter (%) phosphorus meq100g-1 potassium meq100g-1 bulk density (g cm-3) field capacity (%) t0 5.8 1.04 22.39 0.16 1.42 32.58 t1 6.0 1.01 24.97 0.16 1.43 31.20 t2 6.1 0.84 16.23 0.17 1.33 31.98 t3 6.2 1.08 22.43 0.16 1.36 31.85 t4 6.3 1.06 17.66 0.16 1.35 31.54 t5 6.2 0.91 10.93 0.15 1.32 33.81 cv (%) 3.68 18.14 33.04 15.46 6.26 9.52 lsd0.05 ns ns ns ns ns ns in a column, figures with same letter(s) or without letter do not differ significantly, whereas figures with dissimilar letter(s) differ significantly; ns = non significance,[t0= control (no organic matter used), t1=trico-compost (tc) @ 3 t ha -1 used, t2= vermicompost@ ha -1 , t3=mustard oilcake@ 0.5 ha -1 , t4= trichocompost+mustard oil cake , t5=vermicompost+mustard oil cake.] 108 rahman et al. conclusion organic amendment significantly influenced the yield performance of dry direct seeded boro rice and the highest grain yield was obtained with tc @ 0.3 tha -1 (t1). thus, organic matter amendment along with recommended chemical fertilization applicaton is an important management option for obtaining the high grain yield of dry direct seeded boro rice in a rice based cropping system. acknowledgement we are highly grateful to the project implementation unit of bangladesh agricultural research council (barc), farmgate, dhaka-1215 for funding under the competitive research grant (crg) sub-project # 777 under natp2. references ais. 2020. agricultural diary, agricultural information service, khamar bari, dhaka-1215. basak, j.k., m.a. ali, m.n. islam and m.j.b. alam. 2009. assessment of the effect of climate change on boro rice production in bangladesh using ceres-rice model, proceedings of the international conference on climate change impacts and adaptation strategies for bangladesh, 18-20 february 2009. pp.103-113. benbi d.k., c.r. biswas, s.s. bawa and k. kumar. 1998. influence of farmyard manure, inorganic fertilizer and weed control practices on some soil physical properties in a long-term experiment. soil use manage. 14: 52-54. hegde, d.m. and b.s. dwivedi. 1993. integrated nutrient management for dry land agriculture. fert. news. 39(4): 19–26. horta, m.c. and j. torrent. 2007. the olsen p method as an agronomic and environmental test for predicting phosphate release from acid soils. nutr. cycl. agroecosyst. 77: 283–292. minasny, b. and a.b. mcbratney. 2018. limited effect of organic matter on soil available water capacity. european j. soil sci. 69: 39-47. mitran, t. and p.k. mani. 2017. effect of organic amendments on rice yield trend, phosphorus use efficiency, uptake, and apparent balance in soil under long-term rice-wheat rotation. j. plant nutri. 40(9): 1312-1322. pandey, s. and l. velasco. 2005. trends in crop establishment methods in asia and research issues. in: rice is life: scientific perspectives for the 21 st century, proceedings of the world rice research conference, 4–7 november 2004, tsukuba, japan, pp.178–181. rahman, m.m. 2018. dry direct seeded boro rice based cropping patterns for producing more with less water. department of agronomy, bangladesh agricultural university, mymensingh. pp.1-28. rahman, m.m. 2019. potential benefits of dry direct seeded rice culture: a review. fund. and appl. agric. 4(2): 1-15. rahman, m.m., m.a. uddin and m.m. masood. 2012. irrigation water saving, yield performance and costeffectiveness of different rice cultivation systems in boro season. bangladesh agron. j. 15(1): 99106. rahman, m.m. and m.m. masood. 2014. sustaining productivity in boro (winter) season using minimal water through dry direct seeding of rice. j. crop weed. 10(2): 24-30. rahman, m.m., m.m. masood and m.a.r. sarkar. 2020. water management effects on irrigation cutback and yield performance of dry direct seeded boro rice. asian australas. j. biosci. biotechnol. 5(1): 6-14. organic amendment on soil quality and yield performance of boro rice 109 ryan, t., s. pearl, b. sanchez, b. rodrigo, e. badayos, s. paterno and p.c. sta. cruz. 2017. effect of organic amendments and microbial inoculant on nitrogen, phosphorus and potassium use efficiency of sugarcane under acid typic hapludand. j. inter. soc. southeast asian agril. sci. 23(2): 114124. saleque, m.a., m.j. abedin, n.i. bhuiyan, s.k. zaman and g.m. panaullah. 2004. long-term effects of inorganic and organic fertilizer sources on lowland rice. field crop res. 86: 53-65. sarwar, g., n. hussain, h. schmeisky and s. muhammad. 2007. use of compost an environment friendly technology for enhancing rice-wheat production in pakistan. pak. j. bot. 39(5): 1553-1558. shamshuddin, j. and c. fauziah. 2010. alleviating acid soil infertility constraints using basalt, ground magnesium limestone and gypsum in a tropical environment. malaysian. j. soil sci. 14: 1–13 shehzadi, s., z. shah and w. mohammad. 2017. impact of organic amendments on soil carbon sequestration, water use efficiency and yield of irrigated wheat. biotechnol. agron. soc. environ. 21(1): 36-49. vats, m.r., d.k. sehgal, and d.k. meheta. 2001. integrated effect of organic and inorganic manuring on yield sustainability in long-term fertilizer experiments. indian j. agril. res. 35: 19–24. zhou, q., c.x. ju, z.q. wang, h. zhang, l.j. liu, j.c. yang and j.h. zhang. 2017. grain yield and water use efficiency of super rice under soil water deficit and alternate wetting and drying irrigation. j. integra. agric. 16: 1028-1043. mitran, t. and p.k. mani. 2017. effect of organic amendments on rice yield trend, phosphorus use efficiency, uptake, and apparent balance in soil under long-term rice-wheat rotation. j. plant nutri. 40(9): 1312-1322. microsoft word baj 361c__press bangladesh agron. j. 2020, 23(1): 91-99 post-emergence weed control of strip-planted wheat by herbicides t. zahan1, m.r. islam2, m.a. hossain3, m.f. hossain3, q. naher3, s. ishtiaque1, and m.a. ali4 1so, 3sso and 4cso, on-farm research division, bari, gazipur 2cso, dg office, bari, gazipur corresponding e-mail: taslimazahan_tzp@yahoo.com (received: 01april 2020, accepted: 17 july, 2020) keywords: conservation agriculture, minimum tillage, productivity, weed management, wheat abstract transformation of a wheat field from conventionally heavy tillage to stripplanting is beneficial considering soil health improvement and savings in cultivation cost. therefore, an experiment was conducted at the experimental field of on-farm research division, bangladesh agricultural research institute, gazipur during rabi season of 2017-18 and 2018-19 to evaluate some available post-emergence herbicides for managing weeds in strip-planted wheat var. bari gom-30 and to find out the most effective post-emergence herbicide and its suitable rate for controlling weeds under strip tillage system. three postemergence herbicides (ethoxysulfuron, carfentrazone-ethyl plus isoproturon and carfentrazone-ethyl) were tested at their label rate and double of the label rate and their performance were compared with two times manual weeded control treatment. the study revealed that application of ethoxysulfuron at label rate and double of the label rate was effective for grass weed control, but not for broadleaf weeds. application of carfentrazone-ethyl plus isoproturon both at label rate and double of the label rate was effective to control all types of weeds. moreover, the highest grain and straw yields were recorded from label rate application of carfentrazone-ethyl plus isoproturon and its double rate application was also offered similar results in case of grain and straw yields. however; considering undetermined herbicide residual issue and having adverse effect on wheat leaves and finally on yield, the study discourages double of the label rate application of carfentrazone-ethyl plus isoproturon for managing weeds in wheat under strip tillage system. introduction intensive crop cultivation is seriously affecting health and quality of soil. heavy tillage is considered as the major reason of soil erosion as well as soil quality depletion. moreover, high cultivation cost is involved with heavy tillage because of using enough fuel and labour. on the other hand, strip tillage reduces cultivation cost as it requires less fuel, labour and saves time of cultivation (hossain et al., 2015). additionally, strip tillage reduces the rate of soil erosion compare to the conventional tillage because of less disturbance of soil. this minimum tillage also helps to preserve moisture in soil and it keeps soil micro-environment cool by practicing for long period (salahin et al., 2017). furthermore, wheat gives better yield and economic return under strip tillage than conventional system (hossain et al., 2014). 92 zahan et al. but weed is the major barrier to get targetable yield in the strip tillage system (zahan et al., 2016). now-a-days, unavailability and high wage of labour are diverting farmers to choose herbicides for weed control rather than manual weeding. broadleaf weed infestation in wheat not only reduces the yield drastically but it also deteriorates the grain quality (zand et al., 2007). to control broadleaf weeds, there are very few post-emergence herbicides are registered and available in the market of bangladesh. besides, the response of wheat varieties to different post-emergence herbicides might be different because of the genetic and physiological variability within the varieties (punia et al., 1996). therefore, an experiment was designed to evaluate weed controlling efficiency of some available post-emergence herbicides at different application rates in strip-planted wheat cv. bari gom-30 and to identify most suitable and effective herbicide for this new promising wheat variety. materials and methods the experiment was conducted at on-station field of on-farm research division, bangladesh agricultural research institute (bari), gazipur (23°59ˊ12.67567ˊˊ n and 90°24ˊ38.17521ˊˊ e) during rabi season of 2017-18 and 2018-19. the soil of the experimental land was sandy in texture having low organic matter (1.41%) and soil ph 5.02. during the study period prevailing monthly average of maximum and minimum temperature and monthly total rainfall of the experimental site has been presented in fig 1. three post-emergence herbicides named ethoxysulfuron (early post-emergence), carfentrazone-ethyl plus isoproturon (late postemergence) and carfentrazone-ethyl (late post-emergence) were evaluated at their label rate and double of the label rate comparing with a control treatment (manually weeded for two times at 20 and 40 days after sowing). the trade names of the used products of ethoxysulfuron, carfentrazone-ethyl plus isoproturon and carfentrazone-ethyl for the experiment were sunrise 150wp,affinity 50.75wp and hammer 24ec, respectively. the experiment was laid out in rcb design with three replications. the unit plot size was 5 m x 3 m. fig 1. prevailed monthly maximum and minimum averaged air temperature and monthly total rainfall at bari, gazipur during november 2018 to april 2019 0 5 10 15 20 25 30 35 40 n ov '1 7 d ec '1 7 ja n' 18 feb '1 8 m ar '1 8 a pr '1 8 m ay '1 8 ju ne'1 9 ju ly '1 8 a ug '1 8 sep t'1 8 o ct '1 8 n ov '1 8 d ec '1 8 ja n' 19 fe b'1 9 m ar '1 9 a pr '1 9 a ir t em p er a tu re (o c ) 0 50 100 150 200 250 300 350 400 450 r a in fa ll ( m m ) tmax tmin rainfall post-emergence weed control of strip-planted wheat 93 previous crop, t. aman rice was harvested by retaining 20 cm residue in the field. the field was weed-free; therefore, no pre-planting herbicide was applied. seeds of wheat var. bari gom-30 were sown at the rate of 150 kg ha-1 by a two-wheel tractor driven strip planter within the strips apart by 20 cm on 21 november 2017 and 17 november 2018. before strip till, the land was fertilized with phosphorus, potassium and sulphur in the form of triple super phosphate (tsp), muriate of potash (mop) and gypsum @ 160, 50 and 110 kg ha-1, respectively. all fertilizers were broadcasted in the field just before seeding wheat. nitrogen fertilizer was applied in the form of urea @ 200 kg ha-1 in two equal installments. first installment of urea was applied at 15 days after sowing (das) and the second one was at the spike initiation stage. early post-emergence herbicide (ethoxysulfuron) was applied at 15 das and late post-emergence herbicides (carfentrazone-ethyl plusisoproturon and carfentrazoneethyl) were applied at 25 das. shallow irrigation was provided for four times to ensure proper germination and growth of wheat. crop protection measures were also taken as and when necessary. wheat was harvested on 19 march 2018 and 26 march 2019 at maturity. during 2019, crop required 11 days more to get maturity compared to the previous year because crop received heavy rainfall during february 2019 as well as march 2019 and the maturity period was delayed. data on weed density and biomass were collected at 35 das from randomly selected two spots of 50cm×50cm sized quadrat. weed species were also identified and weed population of each species was also counted. data on yield contributing characters were recorded from randomly selected ten plants. yield data were collected from the central 2m×3m area of each plot and converted in to t ha-1. the collected data were analyzed by using a statistical package program ‘r’ (version 3.3.3). results and discussion effect of herbicides on weeds the wheat field was infested by seventeen (17) weed species during rabi season of 2017-18 among which four were grass weeds (cynodon dactylon, digitaria sanguinalis, echinochloa colona and elusina indica), one were sedges (cyperus rotundus) and twelve broadleaf weeds (polygonum hydropiper, chenopodium album, vicia virsuta, physalis heterophylla, enhydra fluctuans, gnaphalium affine, nicotiana plumbaginifolia, portulaca oleracea, eclipta prostrate, amaranthus viridis, alternanthera sessilis and brassica kaber). during 2018-19, nine (09) weed species were identified among which five were grass weeds (cynodon dactylon, digitaria sanguinalis, echinochloa colona, elusina indica and oryza rufipogon) and four (04) were broadleaf weeds (enhydra fluctuans, blumea lacera, brassica kaber, marsilea quadrifolia and amaranthus viridis). the most infested weed species of strip planted wheat was echinochloa colona during both years (table 1). grass weeds were dominant over other types of weeds (73% and 97% of the total infested weeds during 2017-18 and 2018-19, respectively). the study revealed that herbicide treatments reduced densities of all weed species at 35 days after sowing (das) compared to the control. in case of grass weeds, application of ethoxysulfuron at double of the label rate offered the highest density reduction in 2017-18 whereas carfentrazone-ethyl plus isoproturon at double of the label rate gave the highest in 2018-19 (table 2). in case of broadleaf weeds, carfentrazone-ethyl plus isoproturon at double of the label rate provided the highest reduction in densities during both years. during 201718, sedge weed were fully reduced by all herbicide treatments whereas this type of weed was absent in 2018-19. 94 zahan et al. table 1. infested weed species in controlled plots of wheat at 35 days after sowing under strip tillage system in gazipur during rabi season of 2017-18 and 2018-19 weed species local name family life cycle % infestation 2017-18 2018-19 grass cynodon dactylon durba poaceae perennial 13.7 11.6 digitaria sanguinalis angulighas poaceae annual 13.6 25.8 echinochloa colona khudeshama poaceae annual 41.6 41.2 elusina indica chapra poaceae perennial 4.1 12.5 oryza rufipogon wild rice poaceae annual 5.4 sedge cyperus rotundus mutha cyperaceae perennial 2.1 broadleaf polygonum hydropiper biskatali polygonaceae perennial 4.3 vicia sativa wild lentil/vetch fabaceae perennial 1.8 physalis heterophylla foska begun solanaceae perennial 1.5 portulaca oleracea nuneshak portulaceae perennial 2.5 eclipta prostrata keshuti asteraceae perennial 1.8 chenopodium album bathua chenopodiaceae perennial 3.2 gnaphalium affine shetolomi/ bon copi asteraceae perennial 3.2 nicotiana plumbaginifolia bon tamak solanaceae perennial 1.2 enhydra fluctuans helencha asteraceae perennial 2.1 1.6 blumea lacera shialmutra asteraceae perennial 0.4 amaranthus viridis shaknotey amaranthaceae perennial 2.1 alternanthera sessilis chanchi amaranthaceae perennial 1.2 marsilea quadrifolia shushnishak marsileaceae perennial 0.7 brassica kaber bon sharisha brassicaceae perennial 0.8 table 2. effect of post-emergence herbicides on density reduction of weeds at 35 days after sowing of strip-planted wheat during rabi season of 2017-18 and 2018-19 at onstation, ofrd, bari, gazipur treatments % density reduction over control grass weeds sedge weed broadleaf weeds 2017-18 2018-19 2017-18 2017-18 2018-19 control ethoxysulfuron@rd 71.1 61.3 100 90.5 77.8 ethoxysulfuron@2rd 76.4 72.0 100 95.8 88.9 carfentra+isop@rd 52.9 72.7 100 83.9 100.0 carfentra+isop@2rd 54.9 73.7 100 94.0 100.0 carfentra@rd 53.1 59.6 100 88.1 11.1 carfentra@2rd 60.2 66.6 100 96.4 55.6 here, carfentra+isop = carfentrazone-ethyl + isoproturon, carfentra = carfentrazone-ethyl, rd = label rate, 2rd = double of the label rate post-emergence weed control of strip-planted wheat 95 the study demonstrated that herbicide treatments had significant effect on total weed density and biomass at 35 das (fig. 1). the highest number of weeds as well as the highest weed biomass was recorded from control plots during both years. the lowest weed density was counted from ethoxysulfuron at double of label rate application during 2017-18 and from double of the label rate application of carfentrazone-ethyl plus isoproturon during 2018-19. in case of weed biomass, the lowest weight was obtained from double rate application of carfentrazone-ethyl plus isoproturon during both years because of giving effective control on broadleaf weeds. fig. 1. effect of herbicides on (a) total weed density and (b) total weed biomass at 35 days after sowing of wheat under strip tillage system during 2017-18 and 2018-19 at onstation, ofrd, bari, gazipur. effect of herbicides on wheat leaves the effect of the tested post-emergence herbicides on wheat was visually assessed from the day of herbicide application up to harvest. no herbicide had any visual effect on wheat except carfentrazone-ethyl plus isoproturon. in case of carfentrazone-ethyl plus isoproturon, bleaching was observed on leaves of wheat from 3 days of application and later on bleaching turned into leaf yellowing and necrosis. the chemical family of this late post-emergence herbicide is triazolinone plus urea and because of being the family member of urea the site of action of carfentrazone-ethyl plus isoproturon is inhibition of photosynthesis at photosystem ii. that’s why; this herbicide had the bleaching effect on wheat leaves. but the fact is the length of the recovery period from adverse visual effect carfentrazone-ethyl plus isoproturon on wheat leaves. it was visually examined that wheat leaves recovered within 15 days after application (daa) of carfentrazone-ethyl plus isoproturon at label rate; whereas those took 25-30 daa to recovery at double of the label rate application (fig. 2). 0 50 100 150 200 250 300 350 400 450 t o ta l w e e d d e n si ty ( n o . m -2 ) 2017-18 2018-19 p<0.001 at 35 das p<0.001 at 50 das (a) 0.0 10.0 20.0 30.0 40.0 50.0 60.0 t o ta l w e e d b io m a ss ( g m -2 ) 2017-18 2018-19 p<0.001 at 35 das p<0.001 at 50 das (b) 96 zahan et al. fig. 2. effect of carfentrazone-ethyl plus isoproturon at (a) label rate and (c) double of the label rate on wheat leaves at 5 days after application (daa) and at 20 daa for (b) label rate application and for (d) double of the label rate application. effect of herbicides on yield contributing characters and yield of wheat herbicide treatments had significant effect on yield contributing characters as well as yield of strip-planted wheat during both years except spike length and grains spike-1 (table 3 and table 4). during both years, the highest number of tillers and heads m-2, grain yield and straw yield were obtained from carfentrazone-ethyl plus isoproturon at label rate of application and similar results except straw yield were also found from double rate application. the lowest numbers of tillers and heads m-2 and straw yield were recorded from control plots however the lowest grain yield was found from the double rate application of carfentrazone-ethyl. (a) (b) (c) (d) post-emergence weed control of strip-planted wheat 97 table 3. effect of herbicides on yield and yield contributing characters of wheat under strip tillage system during 2017-18, gazipur treatments tillers m-2 (no.) spikes m-2 (no.) spike length (cm) grains spike-1 (no.) grain yield (t ha-1) straw yield (t ha-1) control 280 d 272 d 15.6 34 3.86 c 4.69 c ethoxysulfuron@rd 335 c 322 c 15.3 36 3.89 c 4.86 bc ethoxysulfuron@2rd 348bc 337 c 15.7 36 4.04 bc 5.01 bc carfentra+isop@rd 415 a 405 a 15.8 39 4.82 a 5.85 a carfentra+isop@2rd 390ab 377ab 15.3 34 4.56 ab 5.19 b carfentra@rd 360bc 347bc 15.6 37 4.22 bc 4.78 c carfentra@2rd 350bc 328 c 14.9 34 3.81 c 5.00 bc level of significance *** *** ns ns * *** cv (%) 6.97 6.60 5.14 9.34 8.08 3.93 in a column, means with similar letter(s) are statistically identical as per lsd0.05 here, carfentra+isop = carfentrazone-ethyl + isoproturon, carfentra = carfentrazone-ethyl, cv = coefficient of variance, *** = 0.1% level of significance, * = 5% level of significance, ns = non-significant table 4. effect of herbicides on yield and yield contributing characters of wheat under strip tillage system during 2018-19, gazipur treatments tillers m-2 (no.) spikes m-2 (no.) spike length (cm) grains spike-1 (no.) grain yield (t ha-1) straw yield (t ha-1) control 239 d 236 e 17.5 45.3 2.63 e 3.83 d ethoxysulfuron@rd 253 c 249 de 17.8 47.1 3.10 de 4.73 bc ethoxysulfuron@2rd 255 c 255 cd 17.7 47.9 3.67 bc 4.90 b carfentra+isop@rd 281 a 281 a 18.1 49.1 4.37 a 5.63 a carfentra+isop@2rd 271 ab 271 ab 17.6 51.4 4.13 ab 5.10 b carfentra@rd 266 b 262 bcd 17.7 48.7 3.20 cd 4.43 c carfentra@2rd 271 ab 265 bc 17.9 49.4 3.13 cde 4.73 bc level of significance *** *** ns ns *** *** cv (%) 2.42 2.92 2.60 5.84 8.79 5.22 in a column, means with similar letter(s) are statistically identical as per lsd0.05 here, carfentra+isop = carfentrazone-ethyl + isoproturon, carfentra = carfentrazone-ethyl, cv = coefficient of variance, *** = 0.1% level of significance, * = 5% level of significance, ns = non-significant economic analysis the results showed that plots with recommended dose of carfentrazone-ethyl plus isoproturon had the highest gross return as well as the highest gross margin (table 5). the lowest gross return and gross margin were calculated from the control plots and the reason was related to the high cost involvement for manual weeding. 98 zahan et al. table 5. cost effectiveness of herbicides in strip-planted wheat during 2017-18 and 2018-19 at gazipur treatments 2017-18 2018-19 total cost of production (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) total cost of production (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) control 56770 82833 26063 56070 82833 26763 ethoxysulfuron@rd 43395 97733 54338 42695 97733 55038 ethoxysulfuron@2rd 44295 114900 70605 43595 114900 71305 carfentra+isop@rd 45390 136633 91243 44690 136633 91943 carfentra+isop@2rd 48285 129100 80815 47585 129100 81515 carfentra@rd 43211 100433.3 57222 42511 100433 57922 carfentra@2rd 43926 98733.2 54807 43226 98733 55507 market price (tk. ha-1) of commercial herbicides: pendimethalin = 2525, ethoxysulfuron @ rd = 900, ethoxysulfuron @ 2rd = 1800, carfentrazone-ethyl+isoproturon @ rd = 2895, carfentrazoneethyl+isoproturon @ rd = 5790, carfentrazone-ethyl = 716, carfentrazone-ethyl = 1431 manual weeding cost (tk.): 50labours ha-1 for 2 times weeding (in weed-free check) @ 350 labour-1 day-1, herbicide application cost (tk.): 1labour ha-1 round-1 @ 350 labour-1 day-1, irrigation cost (tk.): 6labours ha-1 for 3 times irrigation during 2017-18 and 4 labours ha-1 for 2 times during 2018-19 @ 350 labour-1 day-1, harvest and post-harvest processing cost (tk.): 45 labours ha-1 @ 350 labour-1day1, market price of grain (tk. kg-1): 30.00, and straw: 1.00. conclusion label rate application of carfentrazone-ethyl plus isoproturon provided the highest grain and straw yields as well as the highest economic return; however, double of the label rate application gave the most effective weed control. therefore, the study suggested application carfentrazone-ethyl plus isoproturon at the label rate in strip-planted wheat cv. bari gom-30 as a profitable weed control practice. references hossain, m.i., m.k. gathala,t.p. tiwari and m.s. hossain. 2014. strip tillage seeding technique: a better option for utilizating residual soil moisture in rainfed moisture stress environments of north-west bangladesh. int. j. recent dev. eng. tech. 2(4): 132-136. hossain, m.i., m. gathala, m.n.a. siddique,m.j. islam and m.a. islam. 2015. long-term bed planting trial for improving productivity and fertility in wheat-mungbean-rice cropping pattern. in: barma, n.c.d., malaker, p.k., mannaf, m.a., sarker, z.i., hossain, m.i., khaleque, m.a., sarker, m.a.z., bodruzzaman, m., hakim, m.a. and hossain, a. (editors), wrc annual report 2014-15, wheat research centre, bangladesh agricultural research institute, nashipur, dinajpur. pp.95-102. salahin, n., k. alam, a.t.a.m.i. mondol, m.s. islam, m.h. rashid and m.a. hoque. 2017. effect of tillage and residue retention on soil properties and crop yields in wheatpost-emergence weed control of strip-planted wheat 99 mungbean-rice crop rotation under subtropical humid climate. sci. res. pub.:1-7. http://www.scirp.org/journal/ojss. punia, s.s., r.s. hooda, r.k. malik and b.p. singh. 1996. response of varying doses of tribenuron-methyl on weed control in wheat. haryana agric. univ. j. res. 26(4): 243253. zahan, t., m.m. rahman and m. begum. 2016. weed control efficacy of herbicides in wheat under strip tillage system. fund. appl. agric. 1(2): 92-96. zand, e., m.a. baghestani, s. soufizadeh, r. pourazar, m. veysi, n. bagherani, a. barjasteh, m.m. khayami and n. nezamabadi. 2007. broadleaved weed control in winter wheat (triticum aestivum l.) with post-emergence herbicides in iran. crop prot.26:746-752. microsoft word baj 363c__press bangladesh agron. j. 2020, 23(1): 107-116 seed yield and yield components of sesame as affected by various weed control methods j. hossain1, m.o. ali2, m.a. islam1, m.s. alam1, m.r. islam3 and j. rahman3 1pulses research centre, 2pulses research sub-station, 3regional agricultural research station, bangladesh agricultural research institute (bari), bangladesh corresponding e-mail: jamilbari11@gmail.com (received: 27 april 2020, accepted: 04 august 2020) keywords: panida 33 ec, sesame, yield, weed control method, weed biomass abstract weed control strategy greatly influences on weed infestation and yield of sesame. an experiment was conducted at regional agricultural research station, ishurdi, pabna during kharif-1 season of two consecutive years 2015-16 and 2016-17 to find out the suitable weed control methods in sesame. it comprises five weed control methods viz., application of panida (t1), application of panida with one hand weeding at 20 dae (t2), one hand weeding at 20 dae (t3), two hand weedings at 20 and 40 dae (t4) and control (no weeding) (t5 ). the experiment was laid out in a randomized complete block design with three replications. among the weed species, cyperus rotundus and digitaria sangunalis were the most abundant weeds. application of panida with one hand weeding at 20 dae (t2) gave the lowest weed density, weed biomass and the highest weed control efficiency followed by application of panida (t1) in both years. weed biomass influenced negatively on plant height, number of capsule plant-1, seed yield and stalk yield. the maximum seed yield and stalk yield were also obtained from t2 which was statistically similar to t1 treatment and the minimum seed yield from t5. economic analysis indicated that t2 gave higher gross return but t1 provided higher gross margin and benefit cost ratio. the treatment, t4 showed higher total variable cost due to the high cost of labour for hand weeding with the increase of variable cost, which affected the marginal return and benefit-cost ratio. however, based on the economic point of view, application of panida in pre-emergence condition (t1) was a profitable and suitable weed control method in summer sown sesame. introduction sesame [sesamum indicum (l.)] is one of the important edible oilseeds cultivated crop in bangladesh. it’s oil content generally varies from 46 to 52% and protein content between 2026%. the production of this crop is 35000 metric tons from 93000 acres of land in bangladesh (bbs, 2019). it is cultivated almost everywhere in the country in the early summer (kharif-1) under rain fed condition. severe weed competition is one of the major constraints of low yield of sesame. prevalence of high temperature with high relative humidity and frequent rainfall during the crop season leads to become wet and moist soil which is favorable for flourishing weed growth and slower plant growth, particularly during early growth stages. a critical period of weed competition in sesame is between 15 and 30 days after seedlings emergence and weeds alone reduce about 50-78% seed yield of sesame (karnas et al., 2019; amare et al., 2011). besides, the rising cost of labour and difficulty of mechanical weeding due to moist soil condition in the summer season call for an alternate weed control measure (punia et al., 2001). 108 hossain et al. though manual weeding is effective and eco-friendly yet they are tedious and timeconsuming. however, chemical weed management is more favourable and effective as they are quick in action, selective in nature, cost effective and efficient to control weeds during the critical period (jain et al., 2001; jain and badkul, 2013). many herbicides are presently used for controlling weeds in rice field. but the information about the weed control methods in summer sown sesame is meager. therefore, the present experiment has been undertaken to find out the appropriate weed control methods for summer sesame. materials and methods location, soil and climatic condition the present study was carried out at the regional agricultural research station, ishurdi, pabna during two consecutive years, 2016 and 2017 (kharif-1 season), geographical position: 24.11ο n; 89.07ο e; under the aez-11 (high ganges river flood plain) (frg, 2012). the soil of the experimental site was medium-high and clay loam texture having 1.22% organic matter, ph 7.40, 0.07% total nitrogen (n), 0.36 meq 100 g-1 soil potassium (k), 10.6 ppm phosphorus (p), 7.2 ppm sulfur (s) and 1.13 ppm zinc (zn). it is under sub-tropical humid climatic conditions and the detailed daily maximum, minimum temperature and rainfall were presented in fig. 1 and fig. 2. the average daily minimum and maximum temperatures were 23.49οc and 33.49οc in the first year, respectively and 24.57 οc and 34.04 οc in the second year during the growing period (march-july). however, the differences in minimum and maximum temperatures were slightly less in the first season than the second season. the total rainfall (march-july) was 1221 mm in 2016 and 4768 mm in 2017, which was higher than first season. treatments and design the experiment was laid out in a randomized complete block design (rcbd) with 3 replications. the unit plot size was 3 m × 4 m. five weed control methods were included in this study. these were application of panida (t1), application of panida with one hand weeding at 20 dae (t2), one hand weeding at 20 dae (t3), two hand weedings at 20 and 40 dae (t4) and control (no weeding) (t5). herbicide, panida 33 ec (pendimethalin, 2.5 l ha-1) was applied as a preemergence condition at moist soil condition just after post sowing irrigation for proper seed germination. spraying was done at the rate of 5 ml panida per liter water with knapsack charger hand sprayer fitted with t-jet nozzle. field experiment sesame var. bari til-4 was used in the experiment. seeds were sown on 10 april and 14 march, 2016 and 2017 respectively in line by hand maintaining 30 cm rows with continuous seeding. fertilizer was applied @ 58-25-40-20-2-1 kg ha-1 of n-p-k-s-zn-b respectively in the form of urea, triple superphosphate, muriate of potash, gypsum, zinc sulphate and boric acid, respectively (frg, 2012). half of n and all other fertilizers were applied at final land preparation and the remaining n was applied as topdressed at 25 days after emergence. tilt 250 ec (propiconazole) and nitro [chlorpyrifos (50%) + cypermathrin (5%)] were sprayed at after flowering to control diseases and insects. no irrigation was applied and weeding was done as per treatments. the crop was harvested on 11 july and 14 june, 2016 and 2017 respectively. data collection species wise weed population was counted at random from an area of one 1 m2 per each plot with quadrate (1m x 1m) at 30 dae (days after emergence) and the dry weight of weed species was determined after in an oven-drying for 72 hours at 70οc. the weight of the dried samples was taken and the average data were expressed as weed biomass (g m-2). the frequency of seed yield and yield components of sesame 109 different weeds was determined and the density of each species was calculated according to odum (1971). ) 2(mareas survey total of weedsnumber total =) 2m (no. density weed 100 species weedallof density total species weedeachof density = density weedrelative × weed control efficiency (wce) was calculated according to the formulae of mani et al. (1973). 100 plot check weedyin weight dry plott treatmenin weight dry -plot check weedyin weight dry = (%)wce × weed persistence index (wpi) was computed using the given formula as suggested by mishra and mishra (1997) plot control in weight dry weed plot treatedin weight dry weed plot treatedin population weed plot control in population weed =wpi × five plants of sesame in each plot were selected randomly to gather data on yield components. data on plant population m-2 of sesame were recorded at physiological maturity and the crop was harvested plot-wise at full maturity. the harvested crop was bundled separately with tag and then brought to the threshing floor. yield and yield components were recorded after harvesting the crop. seed and stalk were dried in the sun to minimize the moisture and converted to yield (kg ha-1). data were recorded on plant height (cm), branches plant-1 (no.), capsules plant-1 (no.), capsule length (cm), seeds capsule-1 (no.), 1000-seed weight (g), seed yield (kg ha-1) and stalk yield (kg ha-1). statistical analysis the analysis of variance (anova) of collected data were performed statistically using ‘r’ software (version: r-3.3.1) (r core team, 2016) and mean separation was done as least significant difference (lsd) at 5% level of significance (gomez and gomez, 1984). yield and yield components of sesame did not vary year to year so pooled analysis was done. fig. 1. daily maximum, minimum temperature and rainfall during the cropping season 2016 at ishurdi. 110 hossain et al. fig. 2. daily maximum, minimum temperature and rainfall during the cropping season 2017 at ishurdi. results and discussion weed indices the number of weed species and relative weed density was affected by different weed control methods at 30 dae (table 1). it was observed that cyperus rotundus (mutha), digitaria sangunalis (anguli), cynodon dactylon (durba) and enhydra fluctuans (helancha) were the common weeds in sesame field. among the weed species, cyperus rotundus and digitaria sangunalis were the most dominant weeds. khan et al. (2011) also reported that these weeds were grown abundantly in kharif-1 season in north-west region in bangladesh. the highest number of weeds (167 m-2 in 2015-16 and 355 m-2 in 2016-17) were recorded from control treatment (t5) and the lowest (67 m-2 in 2015-16 and 115 m-2 in 2016-17) from application of panida with one hand weeding at 20 dae (t2), which was statistically similar with t1. application of panida and hand weeding controlled digitaria sangunalis and other grass weeds and controlled less of cyperus rotundus and broad-leaf weeds, which reduced the density of grass weed than sedge and broad-leaf weeds. the weed density was higher in second growing period (2016-17) than first growing period (2015-16). this might be due to higher minimum and maximum temperatures and total rainfall in the second growing season than the first growing season. weed biomass was significantly influenced by different weed control methods (table 2). the highest weed biomass (155 g m-2and 172 g m-2) was obtained from untreated control (t5) in 2015-16 and 2016-17, respectively and the lowest dry weight (24 g m-2and 25 g m-2) was calculated from t2 in 2015-16 and 2016-17, respectively. the weed control efficiency among the weed control methods ranged from 76 to 85% in 2015-16 and 72 to 85% in 2016-17 (table 2). the highest weed control efficiency was found in application of herbicide with hand weeding at 20 dae (t2), which was 85% in both years. weed persistence index (wpi) was also varied from 0.45 to 0.38 in 2015-16 and from 0.82 to 44 in 2016-17; where application of herbicide with one hand weeding at 20 dae (t2) gave less wpi in both years. this may be attributed to better control of weeds due to suppress of weed emergence through herbicide and weeding under critical period of weed competition critical which might had provided higher weed control efficiency. the results corroborate the findings of rahman et al. (2017), who stated that seed yield and yield components of sesame 111 pre-emergence of herbicide with one weeding at 20 dae provides less weed infestation, weed biomass and high weed control efficiency in sesame. table 1. effect of weed control methods on different weed species’ population and their relative weed density in sesame field at ishurdi during 2015-16 and 2016-17 treatments local name scientific name type 2015-16 2016-17 weed density (no. m-2) relative weed density (%) weed density (no. m-2) relative weed density (%) t1 mutha cyperus rotundus sedge 33 49 123 99 anguli/khuda anguli digitaria sangunalis/ digitaria ischaemum grass 19 28 1 1 others broadleaf 10 15 0 0 durba cynodon dactylon 6 9 0 0 total 68 100 124 100 t2 mutha cyperus rotundus sedge 40 60 114 99 anguli digitaria sp. grass 18 27 1 1 helancha enhydra fluctuans broadleaf 2 3 0 0 durba cynodon dactylon 4 6 0 0 other 3 4 0 0 total 67 100 115 100 t3 mutha cyperus rotundus sedge 36 41 155 80 anguli digitaria sp. grass 52 59 38 20 total 88 100 193 100 t4 mutha cyperus rotundus sedge 39 45 165 86 anguli digitaria sp. grass 47 55 37 19 total 86 100 192 100 t5 mutha cyperus rotundus sedge 81 49 260 73 anguli digitaria sp. grass 86 51 95 27 total 167 100 355 100 lsd (0.05%) 9.74 10.31 cv (%) 5.43 2.79 t1: application of panida; t2: application of panida with one hand weeding at 20 dae; t3: one hand weeding at 20 dae; t4: two hand weeding at 20 and 40 dae; t5: control (unweeded). 112 hossain et al. table 2. weed biomass, weed control efficiency and weed persistence index of sesame in different weed control methods at ishurdi during 2015-16 and 2016-17 treatments weed biomass (g m-2) weed control efficiency (%) weed persistence index 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 t1 37 49 76 72 0.58 0.82 t2 24 25 85 85 0.38 0.45 t3 31b 44 80 74 0.38 0.47 t4 33 41 79 76 0.41 0.44 t5 155 172 lsd (0.05%) 9.02 5.25 cv (%) 8.53 4.20 t1: application of panida; t2: application of panida with one hand weeding at 20 dae; t3: one hand weeding at 20 dae; t4: two hand weeding at 20 and 40 dae; t5: control (unweeded). yield components and yield of sesame plant population had no significant difference among different weed control methods (table 3). plant population varied 28-32 m-2. however, higher plant population was found under application of panida with hand weeding at 20 dae, while lower plant population in weedy check. hossain et al. (2010) also found similar results. the plant height was affected significantly by the treatments (table 3). the maximum plant height was found in application of herbicide with one hand weeding at 20 dae (124 cm), which was statistically similar at application of panida (t1) and one hand weeding at 20 dae (t3). the lowest plant height was recorded in untreated plot (110 cm). the plant height was increased in better weed control management at proper time possibly due to consume of maximum utilization of moisture and nutrients by crop (riaz et al., 2006). the number of branches plant-1 had not significant effect among the treatments, which ranged 2.87-1.97. application of herbicide with one hand weeding at 20 dae (t2) gave the maximum number of capsule per plant (45) which was statistically at par to t1. the lowest number of capsule per plant (37) recorded in t5 and t5. the results were in agreement with the findings of ambika and sundari (2019) that pre-emergence herbicide treatment along with one hand weeding resulted in maximum number of capsules plant-1 of sesame. capsule length and seeds capsule-1 had no significant effect among the treatments. capsule length ranged 1.97 -1.73 cm and number of seeds capsule-1 varied 77-70. the highest thousand seed weight was recorded from t2, which was statistically similar to treatment t1 and t3, and the lowest thousand seed was calculated in t5. similar results have also been reported by akter (2015), who mentioned that 1000-seed weight was higher when two hand weeding was done or herbicide applied at pre-emergence condition. the seed yield of sesame was significantly influenced by different weed management methods (table 4.). higher seed yield (805 kg ha-1) was obtained from t1 followed by t2 treatment and lower seed yield was gained at t5. seed yield was increased 130% in t2 over control which was followed by t1. the improvement in seed yield under these treatments may be attributed to more weed reduction at critical growth stages of crop which favored healthy plant growth to produce maximum number of capsule plant-1 and thousand seed weight which gave higher yield of sesame. the results were in agreement with the findings of rahaman et al. (2017) that pre-emergence herbicide treatment along with one hand weeding resulted in maximum seed yield of sesame. but hossain et al. (2020) reported that two hand weedings at 15 and 30 das gave higher seed yield in sesame. seed yield and yield components of sesame 113 application of panida with one hand weeding at 20 dae (t2) and application of panida (t1) also gave the highest stalk yield (3361 kg ha-1, 3167 kg ha-1 respectively). unweeded treatment (t5) recorded the lowest stalk yield (1180 kg ha-1) due to severe weed competition with sesame which resulted in stunted growth and lower yield. this is in agreement with the findings of mruthul et al. (2015). table 3. yield contributing characters of sesame as affected by different weed control methods at ishurdi during 2015-16 and 2016-17 (pooled) treatments plant population m-2 plant height (cm) branches plant-1 (no.) capsules plant-1 (no.) capsule length (cm) t1 31 123 2.87 43 1.97 t2 32 124 2.63 45 1.87 t3 30 119 1.97 38 1.75 t4 30 117 2.07 37 1.80 t5 28 110 2.40 37 1.73 lsd(0.05) ns 4.66 ns 4.57 ns cv (%) 11.16 3.21 5.11 9.29 12.48 t1: application of panida; t2: application of panida with one hand weeding at 20 dae; t3: one hand weeding at 20 dae; t4: two hand weeding at 20 and 40 dae; t5: control (unweeded); cv = coefficient of variation table 4. yield and yield contributing characters of sesame as affected by different weed control methods at ishurdi during 2015-16 and 2016-17 (pooled) treatment seeds capsule-1 (no.) 1000-seed weight (g) seed yield (kg ha-1) stalk yield (kg ha-1) seed yield increase over control (%) t1 74 1.76 771 3167 120 t2 77 1.91 805 3361 130 t3 73 1.74 524 1583 50 t4 70 1.69 514 1972 47 t5 71 1.49 350 1180 0 lsd(0.05%) ns 0.17 43.56 195 cv (%) 8.54 8.23 6.00 7.07 t1: application of panida; t2: application of panida with one hand weeding at 20 dae; t3: one hand weeding at 20 dae; t4: two hand weeding at 20 and 40 dae; t5: control (unweeded); cv = coefficient of variation. according to regression analysis of the obtained results, plant height, number of capsule plant-1, seed yield and stalk yield were changed to various weed biomass under different treatments (fig. 3). weed biomass accounted for 75% variations in plant height, 23% variations in capsule plant1, 52% variations in seed yield and 39% variations in stalk yield, which could result to the competition for growth resources between weeds and crop. the association analysis was also performed using two years mean data among weed biomass and yield attributing traits, and the 114 hossain et al. results revealed that weed biomass showed a negative correlation with plant height (r = -0.87), number of capsule plant-1 (r = -0.48), seed yield (r = -0.73) and stalk yield (r = -0.63). these results are agreement with the findings of aktar et al. (2013), who stated that increasing trend of weed biomass decreases the yield of the crop. fig. 3. plant height, capsule plant-1, seed yield and stalk yield depended on the weed biomass under different weed control methods. economics economic analysis of different weed control methods on sesame has shown in table 5. the highest gross return (tk. 56350 ha-1) was registered with application of panida with one hand weeding at 20 dae followed by application of panida and the least gross return was registered in unweeded control (tk. 24500 ha-1). but two hand weeding at 20 dae and 40 dae attributed the highest cost (tk. 42750 ha-1) and less cost in (tk. 18750 ha-1) in control (t5). the highest gross margin (tk. 33189 ha-1) and bcr (2.60) were obtained from pre-emergence of panida followed by pre-emergence of panida with one hand weeding at 20 dae. this might be due to high cost of labour for hand weeding resulting in the increase of variable cost and reducing the seed yield and yield components of sesame 115 marginal return, which affect the benefit cost ratio. these findings are supported by other workers (rahman et al., 2017; ambika and sundari, 2019). table 5. economic performance of sesame under different weed control methods treatments gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) bcr application of panida 53970 20781 33189 2.60 application of panida with one hand weeding at 20 dae 56350 32781 23569 1.72 one hand weeding at 20 dae 36680 30750 5930 1.19 two hand weeding at 20 and 40 dae 35980 42750 -6770 0.84 control 24500 18750 5750 1.31 cost:sesame : tk.70 kg-1, panida 33 ec: tk. 325 per 400 ml, urea: tk. 16 kg-1, tsp: tk. 22 kg-1, mop: tk. 15 kg-1, labour : tk. 400 eight hour-1 head-1 conclusion application of herbicide, panida 33 ec in pre-emergence condition with one hand weeding at 20 days after emergence decreased the weed infestation and weeds biomass, and increased the weed control efficiency, which was followed by the application of panida 33 ec in preemergence. although, the treatment of application of panida 33 ec in pre-emergence condition with one hand weeding at 20 days after emergence gave the highest seed yield, on the basis of economic point of view application of panida 33 ec in pre-emergence condition was profitable and suitable weed control method in summer sown sesame. references ambika, m. and a. sundari. 2019. weed management in irrigated sesame (sesamum indicum l.). world scient. news. 131: 272-278. aktar, n. 2015. weed management towards improvement of growth and yield of sesame varieties. m. s. thesis, dept. of agronomy. sher-e-bangla agricultural university, dhaka. p.53. aktar, s., m.a. hossain, a. siddika, n. naher, and m.r. amin. 2013. efficacy of herbicides on the yield of lentil (lens culinaris medik.). the agriculturists. 11(1): 89-94. amare, m. 2011. estimation of critical period for weed control in sesame (sesamum indicum l.) in northern ethiopia. ethiopia j. appl. sci. technol. 2(1): 59-66. bbs (bangladesh bureau of statistics). 2019. yearbook of agricultural statistics-2018. bangladesh bureau of statistics, ministry of planning, government of the peoples republic of bangladesh. p.40. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka 121. p.274. gomez k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john willey and sons, new york, usa. 116 hossain et al. hossain, m.s., a. rahman. m. salim, m. hoque and a.k. hasan. 2020. response of selected sesame varieties to different weed management practices. fund. appl. agril. 5(2): 167–175. doi:10.5455/faa.80257. hossain, a., m.a.s. chowdhury, p.k. malaker, m.s.n. mandal and m.a.z. sarker. 2010. efficacy and economics of herbicides against narrow and broad-leaved weeds of wheat. bangladesh j. weed sci. 1(1): 71-79. jain, v.k., y.s. chauhan and m.k. bhargava. 2001. chemical weed control in soybean (glycine max (l.) merrill.). pestol. 25(10): 11-14. jain, n. and a.j. badkul. 2013. herbicidal weed control in sesame (sesamum indicum l.). j. pharma. phytochem. 2(1): 349-352. khan, m.s.a., m.t. rahman, s.n. mahfuza, s. akther and m. akhteruzzaman. 2011. weed survey in mungbean field at different agro-ecological zones of bangladesh. j. expt. biosci. 2(2): 3946. karnas, z., d. isik, n. tursun and k. jabran. 2019. critical period for weed control in sesame production. weed biol. mng. 19: 121-128. mruthul, t., a.s. halepyati and b.m. chittapur. 2015. chemical weed management in sesame (sesamum indicum l.). karnataka j. agric. sci. 28(2): 151-154. mani, v.s., m.l. pandita, k.c. gautam and b. wandas. 1973. weed hilling chemicals in potato cultivation. pans. 23: 17-18. misra, m. and a. misra. 1997. estimation of ipm index in jute: a new approach. indian j. weed sci. 29: 39-42. odum, e.p. 1971. fundamentals of ecology. w. b. saunders company, philadelphia. 574p. punia, s.s., m. raj, y. ashok and r.k. malik. 2001. bioefficacy of dinitroaniline herbicides against weeds in sesame. indian j. weed sci. 33(3, 4): 143-143. r core team. 2016. r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. url https://www.r-project.org/. riaz, m., m.a. malik, t.z. mahmood and m. jamil. 2006. effect of various weed control methods on yield and yield components of wheat under different cropping patterns. int. j. agric. bio. 8(5): 636-640. rahman, j., m.i. riad, f.s. shikha, r. sultana and n. akter. 2017. weed control methods in sesame. int. j. agron. agri. res. 11(5): 1-6. bangladesh agron. j. 2022, 25(1): 47-56 zinc priming triggers osmoregulation to enhancing growth of soybean (glycine max l.) under salinity f. nowroz, m.m. alam and m.r.h. raihan sher-e-bangla agricultural university, dhaka-1207, bangladesh corresponding e-mail: farzana.flora1992@gmail.com (received: 24 april 2022, accepted: 05 may 2022) keywords: proline, osmotic stress, relative water content, oil crops, legumes abstract soil salinity is becoming an alarming issue in crop production and increasing trend with a disastrous effect in near future. an experiment was conducted following completely randomized design to investigate the responses of zinc (zn) priming (0.5 and 1.0 mm znso4· 7h2o) upon exposure to different salt concentrations (50, 100, and 150 mm nacl) in mitigating salt-induced damages in soybean (glycine max l.). results evidenced that shoot and root length, stem diameter, number of branches, number of leaves, and shoot and root biomass was reduced in a dose-dependent manner compared to control seedling. in a contrary, zn priming resulted in the improvement of the parameters, particularly at a lower dose of salt. moreover, leaf reduced relative water content and proline content were revived in primed seed in comparison with non-primed stressed plants. these triggers soybean plants' tolerance to salt stress. it was concluded that priming seeds with lower concentration of zn (0.5 mm) could alleviate the salt stress through improving plant growth characteristics, relative water content while decreasing proline content. introduction recently, it has been reported that worldwide approximately 20% of land under cultivation, as well as more than 30% of irrigated land, are being affected by salinity (fao, 2019). continuous malpractices in crop cultivation including poor irrigation and drainage system, improper application of mineral fertilizers, intrusion of wastewater or saltwater to cultivable land, and unyielding soil degradation can accentuate salt stress conditions in agricultural land. under salt stress plants are exposed to both osmotic and ionic stress which starts disturbing from germination, changing plant morphological, physiological, and biochemical attributes and ultimately reducing crop yield and quality within a very short period of time (hasanuzzaman et al., 2021). soybean is one of the most popular legumes due to its versatile usage and can withstand a wide array of environmental conditions but different types of adversities like salt stress, extreme temperatures, drought, metal/metalloid toxicity, imbalanced nutrition, ultraviolet radiation, ozone etc. often reduce the yield and quality of crop production (hasanuzzaman et al., 2022). under salt stress, the morphological attributes like plant height, root and shoot fresh weight (fw) and dry weight (dw), leaf number, and branch number are seen to decrease notably in a dose-dependent manner (sadak et al., 2020). in addition, the salient physiological and biochemical characteristics of soybean like chlorophyll contents, carotenoid contents, relative water content (rwc), antioxidant enzymes activities are hampered by an increased rate of proline (pro) content due to imposition of salinity (soliman et al., 2020; rahman et al., 2021) which resulted loss in both yield and quality of soybean. however, different protective tactics such as using salt tolerant genotypes, seed priming, changing faulty agronomic practices, using stress elicitors etc. are now being applied to minimize the losses. in mitigation of salt stress of soybean, seed priming using micronutrient showed the satisfactory result 48 nowroz et al. with an improved plant growth characteristic and withstand better under stress, compared to control or no priming through enhancing antioxidant activities (mangena et al., 2020). zinc (zn) is an important micronutrient that helps in maintaining the stability of cell membrane structure and functions as well. moreover, zn is proved to be advantageous over other treatments in the alleviation of potassium ion content in leaves, photosynthetic pigments, rwc, stomatal conductance, seed yield while lowering sodium ion (na+) content, malondialdehyde and electrolyte leakage percentage and subsequently increasing strong antioxidant defense activities to better withstand in water stress condition caused by salinity (yusefi-tanha et al., 2020; osman et al., 2021). though zn is very beneficial in soybean cultivation and recorded to be a protective tool in crop salt stress resistance as a priming agent, very little work has been done to explore the performance of zn priming in soybean under salt stress condition. the present study aimed to investigate the role of zn priming in conferring soybean salt tolerance. materials and methods seeds of soybean (cv. bari soybean-6) were collected from the bangladesh agricultural research institute (bari), gazipur, bangladesh. the entire experiment was conducted with three replications following a completely randomized design (crd). after collecting, mature, healthy, and uniform-sized seeds were sorted manually and selected for the priming treatment. before priming, seeds were washed with distilled water (dh2o) three times to remove adhering dusts. after then primed with two different concentrations of zinc sulfate (znso4·7h2o), viz. 0.5 and 1.0 mm zn by immersing for 3 h in the dark at room temperature. seeds were then washed again for three times with dh2o and air-dried to obtain a safe moisture content (al-zahrani et al., 2022). both primed and non-primed seeds were sown in 14 l plastic pots (35 cm diameter) in well-prepared soil, mixed with organic matter, urea, triple superphosphate, muriate of potash, gypsum and boric acid as recommended by bari (2019). at 21 days after sowing (das), salinity treatment was imposed on the sets of plants by irrigating with 50, 100, and 150 mm nacl solution and a uniform field capacity was maintained up to 42 das by measuring moisture percentage of the soil with a moisture meter. relevant morphological and physiological parameters were observed at 21 days after the initiation of salinity treatment. measurement of growth parameters growth parameters were obtained from the five randomly selected plants from each treatment at 42 das after 21 d later from the initiation of salt treatment. for measuring the shoot and root length, plants were uprooted and washed with running tap water to remove the adhering soil. then shoot length was measured from the base to the tip of the uppermost leaf, whereas root length was also measured from the base to the longest branch of the root by using a measuring scale and expressed in centimeters (cm). by using a slide caliper stem diameter was measured from three different points of five randomly selected plants and expressed in millimeters (mm). primary branches were counted manually from five randomly selected plants and the values were averaged for determining the number of branches plant−1. similarly, fully expanded leaves were counted and averaged for the determination of the number of leaves plant−1. determination of fresh weight and dry weight of shoot and roots five randomly selected plants were uprooted, washed with dh2o and then roots were separated from shoots. after that, by using a digital balance fresh weight (fw) of roots and shoots was measured. then sun-dried to reduce the initial moisture and followed by oven-drying for 72 h at 80 ○c and weighed again for measuring dry weight (dw) and expressed as g plant−1. the summation of fw and dw of root and shoot was considered as total fw and dw and expressed as g plant−1. parameters were taken at 21 d later from the imposition of salt stress at 42 das. estimation of relative water content (rwc) of leaf zinc priming and soybean growth under salinity 49 the procedure of barrs and weatherly (1962) was followed to estimate the rwc of the leaf at 42 das after 21 d of salt stress imposition. immediately after plucking three randomly selected leaves lamina were weighed for the fw and then dipped in dh2o for 24 h by covering with filter paper. the leaf lamina was weighed again after 24 h for the turgid weight (tw) by removing excess adhering water with blotter paper. these laminas were then oven-dried at 80 ○c for 48 h and weighed for dw. after then, rwc of the leaf was calculated by using the following formula: rwc (%) = fw − dw tw − dw × 100 determination of proline content proline content was determined at 42 das (21 d of salt exposure) by following the method of bates et al. (1973). a leaf sample of 0.5 g was homogenized with 3% sulfosalicylic acid and the homogenate was centrifuged for 12 min at 11,500 ×g. then the 1 ml of aliquot was mixed with 1 ml glacial acetic acid and 1 ml acid ninhydrin solution in a falcon tube and heated at 100 ○c in a water bath for 60 min. after cooling at room temperature, 5 ml toluene was added to the mixture and vortexed and kept for a while to separate a colored chromophore. then the optical density of the chromophore was observed at 520 nm by using a spectrophotometer. finally, the pro content was estimated by plotting the absorbance values against a standard curve and was expressed as µmol g−1 fw. statistical analysis statistical analysis was done by using costat v.6.400 computer-based software (cohort software, monterey, ca, usa) (costat, 2008). the mean values were compared by applying tukey’s hsd test and the value was considered as statistically significant at p ≤ 0.05. results root length, shoot length, and stem diameter of plants noticeable reduction of root length was observed by 29, 28, and 29% in 50, 100, and 150 mm nacl stressed plants, respectively compared to the control plants (figure 1a). priming with 0.5 and 1.0 mm zn improved root length by 41 and 32%, respectively under 50 mm salt-stressed plants in comparison to the corresponding salt-stressed plants only. but under 100 and 150 mm nacl treated plants priming with zn did not improve root length in comparison to the salt-stressed plants alone. upon exposure to 50, 100, and 150 mm nacl, shoot length was declined by 22, 30, and 41%, respectively in comparison to the control plants (figure 1b). when compared to the corresponding unprimed salt-stressed plants, 0.5 mm zn priming improved shoot length by 31 and 20% in 50 and 150 mm nacl stressed plants, respectively, whereas 1.0 mm zn improved by 29 and 19%, respectively. under 100 mm nacl treated plants priming did not enhance shoot length compared to the corresponding salt-affected plants alone. similarly, stem diameter was also decreased by 17, 29, and 34% in salt-affected plants compared to the untreated control plants (figure 1c). the highest increase in stem diameter was found by 13, 19, and 18% in plants under 50, 100, and 150 mm nacl treated plants with 0.5 mm zn priming, respectively in comparison to the corresponding salt-stressed plants without priming. 50 nowroz et al. fig. 1. shoot length (a), root length (b), and stem diameter (c) of soybean as affected by different concentrations of nacl and seed priming with zinc sulfate (znso4·7h2o). denote zn0.5 and zn1.0 seed priming with 0.5 and 1.0 mm znso4·7h2o, respectively. mean value (± sd) was calculated by p ≤ 0.05 applying tukey’s hsd test. number of branches and leaves plant-1 salt stress significantly affects branch and leaf number of soybean plants. branch number reduced by 57% in 50 mm, 70% in 100 mm and 82% in 150 mm, whereas leaf number was declined by 47% in 50 mm, 49% in 100 mm and 58% in 150 mm nacl stressed plants in comparison to the control plants. priming with 0.5 and 1.0 mm zn increased branch number by 75 and 45%, and leaf number by 42 and 33% in 50 mm salt-affected plants compared to its corresponding unprimed salt-stressed plants only (figure 2a, b). fig. 2. number of branches plant−1(a) and the number of leaves plant−1(b) of soybean as affected by different concentrations of nacl and seed priming with zinc sulfate (znso4·7h2o). denote zn0.5 and zn1.0 seed priming with 0.5 and 1.0 mm znso4·7h2o, respectively. mean value (± sd) was calculated by p ≤ 0.05 applying tukey’s hsd test. fresh and dry weight of roots and shoots zinc priming and soybean growth under salinity 51 the highest reduction of root fw and dw was observed by 76 and 73% in 150 mm salt-affected plants, respectively compared to the control plants. priming with 0.5 and 1.0 mm zn in 50 mm nacl conditions, improved root fw by 159 and 136%, and root dw by 147 and 140%, respectively in comparison to the corresponding salt-treated plants without priming. under 100 and 150 mm salt stressed plants priming did not enhance root fw and dw compared to the salt-affected plants alone (figure 3a, b). upon exposure to 50, 100, and 150 mm nacl, shoot fw was declined by 60, 68, and 78%, and shoot dw was declined by 59, 68, and 78%, respectively compared to the control plants. priming with zn (0.5 mm) enhanced shoot fw by 51, 31, and 44%, and shoot dw by 65, 41, and 44% in 50, 100, and 150 mm nacl treated plants in comparison to its corresponding salt-affected plants without priming. on a contrary, improvement of shoot fw (by 42%) and shoot dw (by 52%) were found in 50 mm salt stressed plants when priming was done with 1.0 mm zn compared to the salt-stressed plants only (figure 3c, d). the highest reduction of total fw and dw was also found in salt-affected soybean plants. but priming with zn enhanced biomass accumulation in salt-stressed plants compared to its salt-treated plant alone (figure 3e, f). fig. 3. root fresh weight (a), root dry weight (b), shoot fresh weight (c), shoot dry weight (d), total fresh weight (e), and total dry weight (f) of soybean as affected by different concentrations of nacl and seed priming with zinc sulfate (znso4·7h2o). denote, zn0.5 and zn1.0 as seed priming with 0.5 and 1.0 mm znso4·7h2o, respectively. mean value (± sd) was calculated at p ≤ 0.05 applying tukey’s hsd test. relative water content and proline accumulation in plants 52 nowroz et al. leaf rwc was decreased by 11, 13, and 18% in 50 mm, 100 mm, and 150 mm nacl treated plants compared to the controls. zinc priming at 0.5 and 1.0 mm increased rwc by 9, 8, and 7%, and by 5, 6, and 6% in 50, 100, and 150 mm salt-stressed plants, respectively compared to the corresponding unprimed salt-affected plants only (figure 4a). proline accumulation was upgraded by 103% in 50 mm, 193% in 100 mm, and 333% in mm nacl treated plants in comparison to its untreated controls plants. when compared to the corresponding saltstressed but unprimed plants, pro content reduced by 27, 38, and 14% with 0.5 mm zn, and by 30, 25, and 7% with 1.0 mm zn in plants treated with 50, 100, and 150 mm nacl, respectively (figure 4b). fig. 4. leaf relative water content (a) and proline content (b) of soybean as affected by different concentrations of nacl and seed priming with zinc sulfate (znso4·7h2o). denote, zn0.5 and zn1.0 as seed priming with 0.5 and 1.0 mm znso4·7h2o, respectively. mean value (± sd) was calculated at p ≤ 0.05 applying tukey’s hsd test. phenotypic appearance phenotypic pictures of salt-affected soybean plants with/without zn priming are shown in figure 5. growth was retarded when salt stress was imposed on soybean plants at different concentrations, priming with zn improved plants growth compared to the corresponding unprimed salt-stressed plants (figure 5). zn1.0zn0.5zn0 0 mm nacl zn1.0zn0.5zn0 50 mm nacl 100 mm nacl 150 mm nacl zn1.0zn0.5zn0 zn1.0zn0.5zn0 fig. 5. phenotypic appearance of soybean plants as affected by different concentrations of nacl and seed priming with zinc sulfate (znso4·7h2o). denote, zn0.5 and zn1.0 as seed priming with 0.5 and 1.0 mm znso4·7h2o, respectively. discussion zinc priming and soybean growth under salinity 53 seed priming protects plant from cell damage, elevates water status, dry matter production and stress tolerance with the desired yield under stress condition (abdel hamid et al., 2019). a higher concentration of nacl hinders uptake and translocation of both nutrients and water and leads to an altered cell formation and growth retardation which is a very common phenomenon in salt stressed plants (hasanuzzaman et al., 2022). upon exposure to salt stress, the growth attributes of soybean i.e. shoot and root length, stem diameter, branches and leaves number were reduced and the lowest parameters were recorded at higher salt concentrations (figure 1, 2). these findings are in line with other studies on soybean (sadak et al., 2020; rahman et al., 2021) whereas it has been proved that the growth retardation of soybean increases with increasing salt concentrations. however, alleviation of these growth parameters was noticeable in seedlings pre-treated with zn priming. although both doses of priming helped in attenuating the loss, lower concentration of priming (0.5 mm znso4·7h2o) performed better in most of the parameters, the dose-dependent changes of priming are in accordance with another study (soliman et al., 2020), whereas it was concluded that higher dose priming may show toxicity with an undesirable outcome. the fresh and dry mass of above-ground and below-ground parts of soybean including the total plant fw and dw were decreased in a dose-dependent manner (figure 3) and the higher doses (100 and 150 mm nacl) exposure showed the lowest weight compared to control soybean. but the root structure was affected greatly more than other plant parts even under low (50 mm nacl) salt concentrations. as the destructive na+ ion of salt stress is getting into the plant through the root system, it causes a huge reduction of root growth with a disturbed root structure (silva et al., 2021). as zn priming advantages plants in imbibition of nutrients during seed soaking, it may help in better performance compared to without priming. the positive effect of zn priming under salt stress in growth parameters are also reported in other crops like maize (imran et al., 2018) and wheat (spańo et al., 2020). when plants are imposed to higher salt concentrations, an excess amount of na+ and cl− ions are accumulated in root cells and restrain plants from water absorption through root zone and causes osmotic stress included with lower water potentiality (munns and tester, 2008) and ultimately results in reduced rwc. fig. 6. possible changes of soybean by zinc priming under salt stress which indicates the salt stress tolerance ability of this priming. soybean without any salt stress showed a higher percentage of rwc and that was opposite to salt stressed plant and the lowest value was in the highest salt concentrations. conversely, zn primed soybean subjected to salt stress, exhibited comparatively higher leaf rwc than an unprimed seedling. when plants are treated with zn, higher accumulation of organic osmolytes were recorded under salinity that ultimately resulted in higher turgor and water potentiality (iqbal et al., 2018) and it might 54 nowroz et al. be the reason behind the uplifted rwc in primed seed. similar results of salt stress mitigation in leaf rwc, through priming, has been recorded by mangena (2020) and reported a positive association between soybean plant and priming with a better establishment against salt stress. proline in plant cells act as an osmolyte that enhances protection against cellular membrane degradation and activates enzyme coherence under stress conditions (suresh et al., 2017). so, enhancement of pro content indicated a higher accumulation of organic solute in response to salt stress and the maximum was in higher nacl accumulation whereas control soybean exhibited the lowest pro content. zinc priming in both concentrations diminished the rate of pro content in this experiment which is not a common phenomenon but is supported by another study by sheteiwy et al. (2020). this may be caused due to osmotic adjustment ability of this soybean variety under salt stress conditions. with the application of zn, a possible reduction in ros generated damage to plants lead to a better adaptability of the plant to salinity (sofy et al., 2020). in a nutshell, zn priming can uphold the prime morphological and physiological attributes of soybean in salt stress conditions to some extent (figure 6) and this phenomenon indicates the salt stress tolerance ability of this priming. furthermore, lower concentration (0.5 mm) priming can give a satisfactory outcome even under higher salt concentrations compared to a higher level (1.0 mm) zn priming. acknowledgements the author intends to express her humble gratitude to the ministry of science and technology, bangladesh for providing financial support through r&d fellowship. the author also wants to acknowledge dr. mirza hasanuzzaman, professor, department of agronomy, sher-e-bangla agricultural university for his guidance during the preparation of the manuscript. the authors acknowledge taufika islam anee and abdul awal chowdhury masud assistant professors, department of agronomy, sher-e-bangla agricultural university for their help in critically checking the manuscript. references abdelhamid, m.t., r.r. el-masry, d.s. darwish, m.m.f. abdalla, s. oba, r. ragab, a.e.l. sabagh, m.h.e. kholy and e. omer. 2019. mechanisms of seed priming involved in salt stress amelioration. in: m. hasanuzzaman and v. fotopoulos (eds.). priming and pretreatment of seeds and seedlings. springer, singapore. pp.219-251. al-zahrani, h.s., k. nahar, h.f. alharby, h. alsamadany, k.r. hakeem and m. hasanuzzaman. 2022. zinc supplementation enhances glutathione-mediated antioxidant defense and glyoxalase systems to conferring salt tolerance in soybean (glycine max l.). agron. 12: 1032. doi:10.3390/ agronomy12051032. bari (bangladesh agricultural research institute). 2019. krishi projukti hatboi (in bengali). bangladesh agricultural research institute, gazipur-1701, bangladesh. barrs, h.d. and p.e. weatherley. 1962. a re-examination of the relative turgidity technique for estimating water deficits in leaves. aust. j. biol. sci. 15: 413–428. bates, l.s., r.p. waldren and d. teari. 1973. rapid determination of free proline for water stress studies. plant soil. 39: 205–207. costat. 2008. costat—statistics software version 6.400. cohort software: monterey, ca, usa.fao (food and agriculture organization of the united nations). 2019. available online: http://www.fao.org/globalsoilpartnership/resources/highlights/detail/en/c/1412475/ (accessed on 2 april 2022). zinc priming and soybean growth under salinity 55 hasanuzzaman, m., k. parvin, t.i. anee, a.a.c. masud and f. nowroz. 2022. salt stress responses and tolerance in soybean. in: m. hasanuzzaman and k. nahar (eds.). plant stress physiology perspectives in agriculture. intech open, london. doi:10.5772/ intechopen.102835. hasanuzzaman, m., m.r.h. raihan, a.a.c. masud, k. rahman, f. nowroz, m. rahman, k. nahar and m. fujita. 2021. regulation of reactive oxygen species and antioxidant defense in plants under salinity. int. j. mol. sci. 22: 9326. doi: 10.3390/ijms22179326. imran, m., b. boelt and k-h. mühling. 2018. zinc seed priming improves salt resistance in maize. j. agro. crop. sci. 204: 390– 399. iqbal, m.n., r. rasheed, m.y. ashraf, m.a. ashraf and i. hussain. 2018. exogenously applied zinc and copper mitigate salinity effect in maize (zea mays l.) by improving key physiological and biochemical attributes. environ. sci. pollut. res. 25: 23883-23896. mangena, p. 2020. role of benzyladenine seed priming on growth and physiological and biochemical response of soybean plants grown under high salinity stress condition. int. j. agron. 5: 8847098. doi:10.1155/2020/8847098. munns, r. and m. tester. 2008. mechanisms of salinity tolerance. annu. rev. plant biol. 59: 651–681. osman, h.s., s.m. gowayed, m. elbagory, a.e-d. omara, a.m.a. el-monem, u.a. abd el-razek and e.m. hafez. 2021. interactive impacts of beneficial microbes and si-zn nanocomposite on growth and productivity of soybean subjected to water deficit under salt-affected soil conditions. plants. 10: 1396. doi:10.3390/ plants10071396. rahman, m., k. rahman, k.s. sathi, m.m. alam, k. nahar, m. fujita and m. hasanuzzaman. 2021. supplemental selenium and boron mitigate salt-induced oxidative damages in glycine max l. plants. 10: 2224. doi:10.3390/plants10102224. sadak, m.s., a.r. abd el-hameid, f.s.a. zaki, m.g. dawood and m.e. el-awadi. 2020. physiological and biochemical responses of soybean (glycine max l.) to cysteine application under sea salt stress. bull. natl. res. cent. 44: 1. doi:10.1186/s42269-019-0259-7. sheteiwy, m.s., h. shao, w. qi, p. daly, a. sharma, h. shaghaleh, y.a. hamoud, m.a. el-esawi, r. pan, q. wana and h. lua. 2020. seed priming and foliar application with jasmonic acid enhance salinity stress tolerance of soybean (glycine max l.) seedlings. j. sci. food. agric. 101: 20272041. silva, b.r.s., b.l. batista and a.k.s. lobato. 2021. anatomical changes in stem and root of soybean plants submitted to salt stress. physiological and biochemical responses of soybean (glycine max l.) to cysteine application under sea salt stress. plant biol. 23: 57-65. sofy, m.r., k.m. elhindi, s. farouk, and m.a. alotaibi. 2020. zinc and paclobutrazol mediated regulation of growth, upregulating antioxidant aptitude and plant productivity of pea plants under salinity. plants. 9: 1197. doi:10.3390/plants9091197. soliman, m.h., a.m. abdulmajeed, h. alhaithloul, b.m. alharbi, m.a. el-esawi, m. hasanuzzaman and a. elkelish. 2020. saponin biopriming positively stimulates antioxidants defense, osmolytes metabolism and ionic status to confer salt stress tolerance in soybean. acta physiol. plant. 42: 114. doi:10.1007/s11738-020-03098-w. spanò, c., s. bottega, l. bellani, s. muccifora, c. sorce and m.r. castiglione. 2020. effect of zinc priming on salt response of wheat seedlings: relieving or worsening? plants. 9: 1514. doi:10.3390/plants9111514. suresh, k., a.s. beena, a. monika and s. archana. 2017. physiological, biochemical, epigenetic and molecular analyses of wheat (triticum aestivum) genotypes with contrasting salt tolerance. front. plant sci. 8: 1151. yusefi-tanha, e., s. fallah, a. rostamnejadi and l.r. pokhrel. 2020. zinc oxide nanoparticles (znonps) as a novel nanofertilizer: influence on seed yield and antioxidant defense system in soil grown soybean (glycine max cv. kowsar). sci. total environ. 738: 140240. doi:10.1016/j.scitotenv.2020.140240. about:blank 56 nowroz et al. bangladesh agron. j. 2023, 26(1): 18-27 assessment of yield and yield attributes of tossa jute as affected by variety and field duration m. ahmed1*, j.f. tanni2, s.m.s. parvej3, s.a. jui1, m.s.a. mamun3 and s. mitra4 1department of crop management, bangladesh jute research institute, dhaka-1207, bangladesh 2department of plant pathology, sher-e-bangla agricultural university, dhaka-1207, bangladesh 3department of soil science, bangladesh jute research institute, dhaka-1207, bangladesh 4department of physiology, bangladesh jute research institute, dhaka-1207, bangladesh *corresponding author, email: hadi.sau@gmail.com (received: 4 april 2023, accepted: 18 september 2023) keywords: high yielding variety, field duration, golden fibre, biomass and fibre yield abstract a study was conducted at the jute research sub-station (jrss), tarabo, narayanganj in 2022 to find out the suitable varieties and field duration for tossa jute (corcorus olitorius) harvesting for better fibre and stick yield production. the treatment was assigned of tossa jute varieties (3) viz., bjri tossa pat-7, robi-1 (bjri tossa pat-8) and indian variety jro-524 and four field durations viz. 90, 100, 110, and 120 days, respectively. a factorial rcbd design with three replications was used. results showed that varieties and field duration significantly affected plant height, base diameter, fibre yield and stick yield. the var. jro-524 had the highest fibre yield (2.30 tha−1) than bjri tossa pat-7 and robi-1(2.10 tha−1 and 2.25 tha−1 respectively) when harvested at 90 days after sowing (das). on the other hand, bjri tossa pat-7 and robi-1 produced significantly higher fibre yields (3.20 tha−1 and 3.55 tha−1; 3.45 tha−1 and 3.80 tha−1 respectively) and stick yields (6.15 tha−1, and 6.25 tha−1; 6.67 tha−1, and 6.84 tha−1 respectively) at harvesting 110 and 120 das. the results showed that var. bjri tossa pat-7 and bjri tossa pat-8 could be a better fibre yield and stick yield production when it could be harvested at 120 das. introduction bangladesh's main cash crop is jute (corchorus spp.). the term "jute" is frequently used to refer to the plant and the fibre made from the plant's bark. jute have been produced by cultivating jute on an average of 7-8 lakh hectares of land with 80-90 bales (haque et al., 2020). tossa jute (c. olitorius) produce higher fibre than deshi jute (c. capsularis). in our country, farmers generally cultivate jro-524, as it can be harvested 90 days after sowing (das) (alim et al., 2021). the present study was taken to know the potentiality of high yielding varieties of bangladesh jute research institute (bjri) viz. bjri tossa pat-7 and robi-1(bjri tossa pat-8) compared to jro-524. farmers have little interest in growing bjri tossa pat-7 and bjri tossa pat-8 because of the lengthy vegetative season. on the other hand, the indian variety jro-524 a has shorter vegetative period than the bangladeshi variety (islam et al., 2019). previous results showed that the latest breeding lines sown between the 30th of march and the 10th of april, significantly increased the yield of fibre, with corresponding yields of 3.11 and 3.04 tha−1 at manikganj and 3.13 and 3.11 tha−1 at jashore (ferdous et al., 2021). it was found that c. capsularis cv. jrc-321 was given 30, 45 or 60 kg k ha−1 and 0 or 10 kg b ha−1 harvesting at 80, 100 or 120 days after emergence (maiti and singh, 2019). at increased field duration 120 das resulted in fibre with a good balance of strength and fineness (sarkar and bandyopadhyay, 2000). field duration played an important role in the fibre production of bjri desi pat-10. the first week of april was taken for the sowing of seeds. the plants were harvested at various harvesting ages (90, 100, 110, and 120 days). the results showed that at 110 days of harvesting yield and yield attributes of tossa jute as affected by variety and field duration 19 age, the salt-tolerant cultivar bjri deshi pat-10 produced the highest amount of fibre. (jannatul et al., 2023). tossa jute varieties such as bjri tossa pat-7 and robi-1 (bjri tossa pat-8). robi-1 is the most promising tossa variety for fibre production in bjri. field period can be an important factor for higher production. thus, the present study was taken to determine the appropriate harvesting time for higher fibre production. materials and methods the experiment was conducted at jute research sub-station (jrss), tarabo, narayangang in 2022. the experiment was designed in rcbd with three replications. the unit plot size was (4.0 x 2.5) m2. two high yielding varieties of tossa:viz. bjri tossa pat-7 and robi-1(bjri tossa pat-8) and one indian tossa variety jro-524 were used as planting materials for the study. in the very first week of april, the crop had been sown. the seeds were sown on 1st april 2022 at the rate of 6 kg ha−1 in 30 cm apart lines with hands. all the intercultural operations like thinning, weeding, irrigation, insect pest and disease management were done properly. the experimental fields were prepared through ploughing, harrowing and levelling several times; and fertilizers were applied @ urea 100 kg, triple super phosphate (tsp) 25 kg, muriate of potash (mop) 80 kg and gypsum (sulphate) 40 kg per hectare of land. few amounts of cow dung were previously supplied to add organic matter content to the soil. half of the urea was applied at land preparation and the rest half was top dressed at 45 das. the plants were harvested at 90, 100, 110, and 120 das as part of the treatment. plant height was recorded from 10 randomly selected plants from each plot. the effective plant height was considered from ground level to the top of the leaf at the vegetative phase at the harvest stage. plant height data was measured by a meter scale and converted into cm. the base diameter of the plant was measured with a meter scale as the horizontal distance covered by the plant. the data were recorded from 10 selected plants at harvest and the mean value was counted and expressed in millimeters (mm). the fibres and sticks of each plot were taken after retting and then their weight was recorded and expressed in t ha−1. the statistical analysis of all the gathered data was performed with the help of a computer statistical package named doe-bioresearch in r software. the least significant difference (lsd) and t-test were used to determine the mean differences between the treatments at the 0.05 level. (gomez and gomez, 1984). graphs were created with the help of ggplot2 in r software. results and discussion performance of varieties on plant height the three tossa varieties had a considerable impact on plant height (fig. 1). the box graph indicated that v2 (2.99 m) represented the highest plant height. the smallest plant height was identified in v3 (2.63 m), which is statistically comparable to v1 (2.73m). a similar result was found by hasan et al. (2018) in the southern part of bangladesh bjri tossa pat-8 produced longer plant length over jro-524. 20 ahmed et al. fig. 1: effect of variety on plant height. (v1= bjri tossa pat-7, v2= robi-1(bjri tossa pat-8) and v3= jro-524). effect of field duration on plant height field duration influenced significantly plant height (fig. 2). the highest plant height (3.83m) was found at d4 which was statistically equivalent to d3. the smallest plant height was (2.18 m) found in d1 which was statistically similar to d2. the highest plant height was 75.68% greater than the lowest plant height found in d1. the result indicated that the plant height increased with the increase in field duration. the field duration of 120 das was given the highest plant height. islam et al. (2019) found a positive increase in plant length with an increase in field duration up to 120das in tossa jute production. similarly, debnath et al. (2018) reported that the increasing pattern of plant height was almost the same in case of variety bjri tossa pat-6 and bjri tossa pat-6 up to 90 das and after 90 das this parameter increase pattern remained sharper in case of variety bjri tossa pat-6 compare to bjri tossa pat-5 upto 120 das. fig. 2. effect of field duration on plant height. d1= 90 das, d2= 100 das, d3= 110 das, d4= 120 das. yield and yield attributes of tossa jute as affected by variety and field duration 21 interaction effect of variety and field duration on plant height the interaction effect of varieties and field duration differ significantly (table 1). the highest plant height (3.75 m) was found in the v2d4 treatment combination (bjri tossa pat -8 at field duration 120 das) which was statistically comparable to v1d4 and v2d3. the second height value (3.62 m) was found from the v2d3 combination which was statistically equivalent to v1d3 and v1d4. the lowest value (2.1 m) was found from the v1d1 treatment combination (bjri tossa pat7 at field duration 90 das) which was statistically similar to v1d2, v2d1, v2d2, v3d1 and v3d2). the height plant height found in the v2d4 treatment combination was 78.57% greater than the lowest value found in the v1d1 treatment combination. islam et al. (1995) found similar results that field duration increased plant height by 3.70 m in 120 das in tossa jute production and weng et al. (1990) also reported that there was a positive growth in tossa jute stem due to increasing field duration. table 1. interaction effect of variety and field duration on plant height of tossa jute treatments plant height (m) v1 x d1 2.10f v1 x d2 2.30ef v1 x d3 3.20bc v1 x d4 3.35abc v2 x d1 2.20f v2 x d2 2.40ef v2 x d3 3.62ab v2 x d 4 3.75a v3 x d1 2.25ef v3 x d2 2.50ef v3 x d3 2.70de v3 x d4 3.05cd lsd(0.05) 0.48 cv (%) 10.16 v1 bjri tossa pat-7, v2= robi-1(bjri tossa pat-8), v3= jro-524, d1= 90 das, d2= 100 das, d3= 110 das, d4= 120 das. performance of variety on base diameter different varieties had a significant effect on plant base diameter (fig. 3). fig. 3. effect of variety on jute base diameter. legends: v1= bjri tossa pat-7, v2= robi-1 (bjri tossa pat-8) and v3= jro-524. 22 ahmed et al. the height base diameter (17.88 mm) was found from v2, robi-1(bjri tossa pat-8). the smallest base diameter (17.03 mm) was found from v3 (jro-524) which was statistically identical to v1 (bjri tossa pat-7). hsu and chi (1976) reported that the basal diameter of tossa varieties had a great impact on fibre yield production and it was numerically greater in bjri tossa pat-6 and bjri tossa pat-7 than in jro-524 (ferdous et al., 2020). it was reported that basal diameter was higher in bjri high yielding varieties than those of indian local varieties (mukul et al., 2021). effect of field duration on base diameter field duration had a great influence on the plant base diameter, as the field duration increased plant base diameter increased (fig. 4). the highest base diameter (20.07 mm) was found from d4 at 120 das. the second and third highest base diameter was found in d2 and d3 at 100 das and 110 das, respectively. the lowest value (13.55 mm) was found from d1 (90 das). the results indicated that the longer field duration had a positive influence on plant base diameter. the highest base diameter found in d4 was 48.11% greater than the lowest one found in d1. das et al., (2014) reported the same results that tossa jute reached a maximum in breath length when it got the fuller length of field period of 120 das. fig. 4. effect of field duration on plant base diameter. d1= 90 das, d2= 100 das, d3= 110 das, d4= 120 das interaction effect of variety and field duration on base diameter the highest base diameter (21.50 mm) was recorded from the v2d4 treatment combination at 120 das (table 2). table 2. interaction effect of variety and field duration on the base diameter of tossa jute treatment base diameter (mm) v1 x d1 13.30g v1 x d2 17.20f v1 x d3 18.45d v1 x d4 20.20b v2 x d1 13.35g v2 x d2 17.40ef v2 x d3 19.25c v2 x d4 21.50a v3 x d1 14.00g v3 x d2 17.65ef v3 x d3 18.00de v3 x d4 18.50d lsd(0.05) 0.75 cv (%) 2.54 v1 = bjri tossa pat-7, v2 = robi-1(bjri tossa pat-8), v3 = jro-524, d1 = 90 das, d2 = 100 das, d3 = 110 das, d4 = 120 das yield and yield attributes of tossa jute as affected by variety and field duration 23 the second highest value was found in the v1d4 (bjri tossa pat-7 at 120 das field duration). the lowest base diameter (13.30 mm) was recorded in v1d1 which was statistically identical to v2d1 and v3d1 respectively. the highest basal diameter found in v2d4 was 61.65% greater than the lowest basal diameter found in v1d1. weng et al. (1990) discovered that tossa jute produced higher basal diameter with increasing field duration as it had got more vegetative period with long days of sunlight. similar results were also found by ferdous et al. (2020) that tossa jute got a maximum basal diameter with a longer vegetative period of 120 das. performance of variety on fibre yield fibre yield had been differed significantly by the different varieties of tossa jute (fig 5). the highest fibre yield (3.00 t ha−1) was found from v2 (bjri tossa pat-8) which was statistically similar to v2 (bjri tossa pat-7) and the lowest fibre yield (2.68 t ha−1) was found from v3 (jro-524). bjri tossa pat-8 produced 11.94% higher than jro-524. ahmed et al. (2023) reported that bjri tossa pat-8 produced a higher fibre yield than jro-524 and was highly significant. plants with greater plant height had longer basal length resulting in increased fibre weight that ultimately improved the yield of the variety. ferdous et al. (2021) reported similar results on fibre production for tossa jute. fig. 5. effect of variety on fibre yield, v1= bjri tossa pat-7, v2 = robi-1(bjri tossa pat-8) and v3= jro-524 effect of field duration on fibre yield the fibre yield of tossa was significantly influenced by different field duration (fig. 6). fig. 6. effect of field duration on fibre yield. d1= 90 das, d2= 100 das, d3= 110 das, d4= 120 das 24 ahmed et al. the highest fibre yield (3.42 t ha−1) was found from d4 at 120 das. the second and third fibre yield (3.18 tha-1 and 2.57 tha−1) were found from d3 and d2, respectively. the lowest fibre yield (2.22 t ha−1) was found from d1 at 90 das. the highest fibre yield found from d4 was 54.05% greater than the lowest fibre yield found in d1. bjri tossa pat-8 produced the maximum number of plantm-2, the tallest plant, maximum base diameter and largest leaf area at 120 das. thus, bjri tossa pat-8 got superior on growth, yield and yield contributing traits as well as their sustainability (rafiq et al., 2020, ferdous et al., 2020). interaction effect of variety and field duration on fibre yield the interaction effect of varieties of tossa jute and field duration was significant on fibre yield (table 3). table 3. interaction effect of variety and field duration on fibre yield and stick yield of tossa jute treatment fibre yield (t ha−1) stick yield (t ha−1) v1 x d1 2.10h 4.70c v1 x d2 2.55efg 5.05c v1 x d3 3.20bc 6.15b v1 x d4 3.55ab 6.25ab v2 x d1 2.25gh 4.80c v2 x d2 2.50fg 5.10c v2 x d3 3.45ab 6.67ab v2 x d4 3.80a 6.84a v3 x d1 2.30fgh 5.00c v3 x d2 2.65def 5.15c v3 x d3 2.90cde 5.17c v3 x d4 2.93cd 5.20c lsd(0.05) 0.38 0.63 cv (%) 4.81 6.78 v1= bjri tossa pat-7, v2 = robi-1(bjri tossa pat-8), v3= jro-524, d1= 90 das, d2 = 100 das, d3 = 110 das, d4 = 120 das. the highest fibre yield (3.80 t ha−1) was produced in v2d4 (bjri tossa pat-8 at 120 das) which was statistically similar to v1d4 and v2d3, respectively. the second highest fibre yield (3.55 t ha−1) was found in v1d4. however, there are no significant differences among v1d4, v1d3 and v2d3. the lowest fibre yield (2.10 t ha−1) of this study was found in v1d1 (bjri tossa pat-7 at 90 das) which was statistically similar to v2d1 and v3d1, respectively. the highest fibre yield found in the v2d4 was 80.95% higher than the lowest fibre yield found in the v1d1 treatment combination. the result showed that v3d1 and v3d2 gave numerically higher fibre yields than the v1d1, v1d2, v2d1 and v2d2, respectively. but fibre yield was decreased in v3d3 and v3d4 compared to v1d3, v1d4, v2d3 and v3d4 treatment combinations. this observation was agreed with ferdous et al. (2021) who worked with tossa jute and reported that bjri tossa pat-8 jute produced higher fibre yield at 120 das than 90 das. interaction effect of variety and field duration on stick yield stick yield was significantly influenced by the interaction effect of variety and field duration (table 3). the highest stick yield (6.84 t ha−1) was found in v2d4 (bjri tossa pat-8 at 120 das) which was statistically similar to v1d4 and v2d3, respectively. the second highest stick yield (6.67 tha-1) was statistically comparable to v1d3 and v1d4. the lowest stick yield (4.70 t ha−1) was found in the v1d1 treatment combination and there were no significant differences among v1d2, v2d1, v2d2, v3d1, v3d2, v3d3 and v3d4. bjri tossa pat-8 produced a 45.53% higher stick yield than the jro-524. the result indicated that stick yield was higher in v3d1 and v3d2 than the v1d1, v1d2 and v2d1, v2d2. but v1d3, v1d4 and v2d3, v2d4 gave higher stick yields than v3d3 and yield and yield attributes of tossa jute as affected by variety and field duration 25 v3d4. islam et al. (1995) indicated that bjri tossa pat-6 and bjri tossa pat-7 produced higher stick yield with longer plant height at 120 das and hsu and chi (1976) also claimed that tossa jute produced higher biomass in longer field duration at 115-120 das. performance of variety on stick yield the stick yield of tossa significantly differed with respect to varieties (fig.7). v2 (robi-1) gave the highest stick yield (5.85 tha table 3. interaction effect of variety and field duration on fibre yield and stick yield of tossa jute) treatment fibre yield (t ha−1) stick yield (t ha−1) v1 x d1 2.10h 4.70c v1 x d2 2.55efg 5.05c v1 x d3 3.20bc 6.15b v1 x d4 3.55ab 6.25ab v2 x d1 2.25gh 4.80c v2 x d2 2.50fg 5.10c v2 x d3 3.45ab 6.67ab v2 x d4 3.80a 6.84a v3 x d1 2.30fgh 5.00c v3 x d2 2.65def 5.15c v3 x d3 2.90cde 5.17c v3 x d4 2.93cd 5.20c lsd(0.05) 0.38 0.63 cv (%) 4.81 6.78 v1= bjri tossa pat-7, v2 = robi-1(bjri tossa pat-8), v3= jro-524, d1= 90 das, d2 = 100 das, d3 = 110 das, d4 = 120 das. and the second highest from v1 (bjri tossa pat-7) which was statistically similar to v1. the lowest value (5.13 tha−1) was found in the v3 (jro-524). the stick yield of bjri tossa pat-8 was 14.03% higher than jro-524. debnath et al. (2018) observed that bjri tossa pat-8 with longer plant height and basal diameter produced a higher stick yield. das et al. (2014) found a similar result for stick yield. fig. 7. effect of variety on stick yield. v1= bjri tossa pat-7, v2= robi-1(bjri tossa pat-8) and v3= jro-524 26 ahmed et al. effect of field duration on stick yield field duration had a great impact on stick yield (fig 8). the stick yield differed significantly due to different field durations. the highest stick yield (6.09 t ha−1) was found from d4 (120 das) which was statistically similar to d3 (110 das). the lowest stick yield (4.83 t ha−1) was found from d1 (90 das) which was statistically identical to d2 (100 das). the stick yield at 120 das was 26.08% higher than the stick yield at 90 das. stick yield was increased with the increase in field duration (islam et al., 1995). kamat et al. (2002) also found a similar result when working with hemp plants, reporting that it produced higher biomass at 60-70 das than at 30-40 das. fig. 8. effect of field duration on stick yield. d1= 90 das, d2= 100 das, d3= 110 das, d4= 120 d conclusion the varieties and field duration had a significant effect on plant height, base diameter, fibre yield and stick yield for tossa jute production. the outcomes of the present study concluded that bjri tossa pat-7 and bjri tossa pat-8 (robi-1) gave lower fibre yield when harvested at 90–100 das compared to the popular indian tossa variety jro-524. on the other hand, bjri tossa pat-7 and bjri tossa pat-8 (robi-1) gave higher fibre yield when it was harvested at 110-120 das compared to jro-524. the results concluded that bjri tossa pat-7 and bjri tossa pat-8 could be a better choice for fibre yield and stick yield production when it would be harvested at 120 das. references ahmed, m., j.f. tanni, s.a. jui, s.m.s. parvej and m.s.a. mamun. 2023. tossa jute production under the influence of variety and growth period. j. exp. biosci. 14(2): 25-36. alim, m.a., a. sultana, t. sultan and j. ferdous. 2021. fertilizer requirement for maximum growth and yield of salt tolerant variety bjri deshi pat-10. int. j. innov. res. technol. 1(2): 9-12. bbs (bangladesh bureau of statistics). 2022. yearbook of agricultural statistics of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. das, b., k. chakrabarti, s. tripathi, and a. chakraborty. 2014. review of some factors influencing jute fiber quality. j. nat. fibers. 11(3): 268–81. debnath, m.r., m.m. islam, m.z.a. rafiq, p.n. nandi and d.n. nandi. 2018. dry matter accretion at different harvesting stages of newly released jute variety (bjri tossa pat6). bangladesh j. environ. sci. 35: 67-70. yield and yield attributes of tossa jute as affected by variety and field duration 27 ferdous, j., m.s. hossain, m.a. alim and m.m. islam. 2020. effect of field duration on yield and yield attributes of tossa jute varieties at different agroecological zones. bangladesh agron. j. 22(2): 7782. ferdous, j., m.s. hossain, m.y. sarker, m.a. alim and m.m. islam. 2021. effect of sowing date on fibre yield and yield attributes of advanced breeding line o-0412-9-4 and o-043-7-9 of tossa jute (corchorus olitorius l.). bangladesh agron. j. 25(1): 1-6. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. second edn. john wiley and sons inc., new york. pp.304-307. hassan, k.m., m.i. bhuyan, m.k. islam, m.f. hoque, m. monirul, k.m.m. hassan and m. ferdous. 2018. performance of some jute & allied fibre varieties in the southern part of bangladesh. int. j. adv. geosci. 6(1): 117-121. haque, s.m.a., m. kamrujjaman, m.s. hossain, j. ferdous and m.t. rahman. 2020. disease incidence, seed quality and yield of jute variety cvl-1 affected by seeds stored in different types of containers. int. j. sustain. agric. technol. 16(5): 08-13. hsu, s.t. and c.y. chi. 1976. studies on the effect of different harvesting periods on yield and quality of jute fibre. field crop res. 29(3): 190. islam, m.m., j. ferdous and m.k. debnath. 2019a. performance of cvl-1 seedling growth and dry weight attributes under greenhouse and field conditions as affected by seed source and seedling age. agric. food sci. 6(1):109-113. islam, m.m., j. ferdous and m.m. hoque. 2019b. assessment of o-9897 seedling growth and dry weight parameters under greenhouse and field conditions as influenced by seed source and seedling age. am. j. plant biol. 4(3): 28-33. islam, m.m., k.r. haque, a.a. miah, n. nuruzzaman and m.a. rahman. 1995. response of stage of the harvest to yield, yield components and quality of jute fibre. bangladesh j. jute fib. res. 20(1): 915. jannatul, f., m.a. alim, t. sultan and a. sultana. 2023. comprehensive research effect of harvesting age on fibre yield and yield contributing characters of highly salt tolerant c. capsularis variety bjri deshi pat-10. int. j. multidisip. res. 6(1): 4-7. kamat, j., d.n. roy and k goel. 2002. effect of harvesting age on the chemical properties of hemp plants. j. wood chem. technol. 22(4): 285-293. maiti, r.k. and v. singh. 2019. a review of research on jute production and quality. farm manag. 4(2): 97133. mukul, m.m., n. akter, m.m. islam, m.s.h. bhuiyan, m.g. mostofa, r.k. ghosh and m.a. ali. 2021. morpho-phenetical study of high yielding tossa jute variety bjri tossa pat 7 (mg-1) for bast fibre yield and qualities. heliyon 7(10). rafiq, a.l., m.z. tasnime, n. zehad, m. mohebbullah, a.b.m.z. hoque and m.j. alam. 2020. varietal performance of jute based on yield and yield contributing characters. int. j. bus. soc. sci. res. 8(3): 63–67. sarkar, a.k. and p.k. bandyopadhyay. 2000. effect of potassium, boron and crop age on the yield and quality of white jute (corchorus capsularis l.). int. j. acad. res. 4(1): 73-77. weng, c.h., n.x. lai and b.f. shao. 1990. effect of harvesting dates on fibre yield and quality of kenaf and jute. field crop res. 43(11): 1076. bangladesh agron. j. 2021, 24(2): 55-61 yield and quality of some tropical sugarbeet genotypes under bangladesh conditions m.a.t. sohel*, m.a.e. hossain, a.m.s. rahman, f.h. shanta and m.r.r. rajib bangladesh sugarcrop research institute, ishurdi, pabna. *principle scientific officer, agronomy & farming systems division corresponding e-mail: atsohel@yahoo.com (received: 17 august 2021, accepted: 19 september 2021) keywords: genotype, yield and quality, tropical sugarbeet abstract the experiment was conducted at the experimental farm of agronomy and farming systems division, bangladesh sugarcrop research institute (bsri), ishurdi, pabna, bangladesh during 2012-13 cropping season to assess the comparative performance of yield and quality of six tropical sugarbeet genotypes viz., cs 0327, hi 0473, cs 0328, hi 0044, shubhra and cauvery. the different genotypes showed significant differences in their yield and yield components, such as beet length, beet girth, beet yield, shoot yield, sugar yield and harvest index. the quality parameters, such as total soluble solids or brix, sucrose percentage and apparent purity percentage of sugarbeet were also different among the genotypes. maximum beet length (31.38 cm), beet girth (36.09 cm), beet yield (75.46 t ha-1), shoot yield (38.46 t ha-1) and sugar yield (11.82 t ha-1) were found in cauvery followed by cs 0328. in case of sugarbeet quality, the maximum total soluble solids (tss) and sucrose percentage (21.90% and 15.68%, respectively) were recorded in cauvery followed by the genotype cs 0328 (21.52% and 15.50%, respectively). so, it was concluded that tropical sugarbeet genotype cauvery appeared as the best one with respect to yield and quality parameters followed by cs 0328 under bangladesh conditions. introduction sugarbeet (beta vulgaris) is one of the most important sugar crops of temperate climates (abdelmotagally and attia, 2009). it ranks the second as sugar crop after sugarcane in the world. sugarbeet is a fleshy root crop processed for sugar production. sugarbeet is mainly a temperate crop but can be successfully grown under tropical climatic conditions. sugarbeet growth, yield and quality are influenced by different variety, spacing, various agronomic practices, fertilizer management, date of sowing etc. choosing the sugarbeet hybrid with high yield potential is important as well as good adapted agronomic measures and practices, synchronized with requirements and needs of the plant (ulakovic et al., 2015). variety plays an important role on the performance of tropical sugarbeet. all sugarbeet genotypes cultivated in bangladesh are imported from foreign countries; so, it is preferable to evaluate them under bangladesh conditions especially under newly reclaimed soil to select the best suited ones. yield and yield parameters of sugarbeet differed significantly among the varieties /lines (bairagi et al., 2013). lamani and halikatti (2019) observed that the genotype cauvery recorded significantly higher yield, yield attributes and quality parameters than genotype indus. brac (2010) conducted field experiment with nine varieties/lines in patuakhali and noakhali, i.e. in the coastal area of bangladesh. among the nine sugarbeet varieties/lines cauvery gave the highest beet yield (120 t ha-1) and proved to be highly tolerant to salinity. hossain et al. (2011) conducted an experiment in bangladesh agricultural university farm, mymensingh with five sugarbeet varieties/lines, where eb-0809 gave the highest mailto:atsohel@yahoo.com https://www.frontiersin.org/articles/10.3389/fpls.2018.01041/full#b12 56 sohel et al. yield (89.74 t ha-1) compared to other varieties. sugarbeet is a new crop in bangladesh and until now it has not been grown commercially in a large scale. systematic research to improve the yield and quality of sugarbeet through best agronomic practices is also scare. considering the above facts, the present study was carried out to evaluate yield, yield related parameters and quality of six selected tropical sugarbeet genotypes under bangladesh conditions. materials and methods the experiment was conducted at bsri farm, ishurdi (aez-11) during rabi cropping season of 201213 following a randomized complete block design with three replications. each plot size was 4.0 m × 4.0 m i.e. 16 m2. the seeds were sown on 04 november 2012 at about 2 cm depth at a distance of 50 cm from line to line and 20 cm from plant to plant. six tropical sugarbeet genotypes, viz. cs 0327, hi 0473, cs 0328, hi 0044, shubhra and cauvery were used as treatment materials. the land was uniformly fertilized with 260 kg urea, 100 kg triple super phosphate (tsp), 225 kg muriate of potash (mop), 100 kg gypsum, 10 kg zinc sulphate and 7 kg boric acid ha-1 (bsri, 2011). three weedings were done at 30, 50 and 70 das for the study. plants were thinned at the age of 35 days after sowing to obtain one plant per hill. earthing-up was done to cover the root base and to facilitate drainage operation. the experimental field required 3 irrigations applied at 45, 90 and 125 das. data on yield and yield contributing components, viz. beet length, beet girth, beet yield, shoot yield, sugar yield, harvest index, total soluble solids or brix, sucrose percentage and apparent purity percentage were collected following standard methods. all data were statistically analyzed according to the technique of analysis of variance (anova) by means of “statistix-10” computer software package for windows version (statistix-10, 2013) and least significant difference (lsd) method was used to test the differences between treatment means at 5% level of probability. results and discussion yield, yield contributing characters and quality in respect of beet length (cm), beet girth (cm), beet yield (t ha-1), shoot yield (t ha-1), sugar yield (t ha-1), harvest index (hi), total soluble solids (tss %) or brix (%), sucrose percentage (%) and apparent purity percentage (%) are presented and discussed here under: yield and yield components beet length and beet girth beet length and beet girth were significantly responded to different sugarbeet genotypes at harvest (fig. 1 and fig. 2). the maximum beet length and beet girth (31.38 cm and 36.09 cm) was obtained from the variety cauvery which was statistically similar with cs 0328 (29.99 cm and 35.01 cm), respectively. the lowest beet length (27.80 cm) and beet girth (30.33 cm) was measured from hi 0044 and shubhra, respectively. enan et al. (2009), hossain et al. (2011) and bairagi et al. (2013) were also found genotypic differences in beet length and girth. yield and quality of some tropical sugarbeet genotypes 57 fig. 1. effect of genotypes on beet length of six tropical sugarbeet genotypes at harvest. fig. 2. effect of genotypes on beet girth of six tropical sugarbeet genotypes at harvest. beet yield and shoot yield beet and shoot yield were significantly influenced by sugarbeet genotypes at harvest (fig. 3 and 4). among the genotypes, the maximum beet yield and shoot yield (75.46 t ha-1 and 38.46 t ha-1, respectively) was recorded in cauvery, which was statistically similar with cs 0328 (72.07 t ha-1 and 37.59 t ha-1, respectively), while the lowest yield (57.57 t ha-1 and 25.25 t ha-1, respectively) obtained from shubhra. the highest beet yield and shoot yield were attributed to the higher number of leaves plant-1, individual beet and shoot fresh weight plant-1. these results agreed with the findings of brac (2010), jozefyova (2004), rahman (2011) and badawi et al. (2003) that genotypic differences influenced the plant morphological characters. 58 sohel et al. fig. 3. effect of genotypes on beet yield of six tropical sugarbeet genotypes at harvest. fig. 4. effect of genotypes on shoot yield of six tropical sugarbeet genotypes at harvest. sugar yield and harvest index (hi) sugar yield and harvest index were significantly influenced by tropical sugarbeet genotypes at harvest (fig. 5 and 6). the maximum sugar yield (11.82 t ha-1) was found in cauvery followed by cs 0328 (11.17 t ha-1) and genotype hi 0044 gave the lowest amount of sugar yield (8.58 t ha-1). the highest value of harvest index was achieved in genotype cs 0327 (0.716), and the genotype cs 0328 gave the lowest (0.657). sugar yield varied significantly due to significant difference in beet yield. the results reflected that genotype cauvery and cs 0328 was the suitable genotype in terms of sugar yield. similar findings were reported by marlander and rothe (2005), azzazy et al. (2007) and aly (2006) that there was a significant genotypic difference in producing sugar yield under tropical conditions. yield and quality of some tropical sugarbeet genotypes 59 fig. 5. effect of genotypes on sugar yield of six tropical sugarbeet genotypes at harvest. fig. 6. effect of genotypes on harvest index of six tropical sugarbeet genotypes at harvest. beet quality characters total soluble solids or brix genotypes were significantly influenced the total soluble solids in juice of tropical sugarbeet root (table 1). the maximum tss (21.90 %) was recorded in cauvery followed by cs 0328 (21.52 %) where the genotype hi 0044 gave the lowest tss (19.79 %). sucrose percentage sucrose percentage in tropical sugarbeet was significantly influenced by the genotypes (table 1). the results revealed that cauvery had the maximum concentration of sucrose (15.68 %), which was 60 sohel et al. statistically similar with cs 0328 (15.50 %). the lowest concentration (13.95 %) of sucrose was found in the genotype hi 0044. superiority at tss and sucrose % may be due to the genetic structure of this variety. this result was in agreement with the findings of ntwanai and tuwanai (2013), osman et al. (2003), islam et al. (2012) and enan et al. (2009) also that sucrose content varied due to genotypic differences. table 1. total soluble solids, sucrose percentage and apparent purity percentage of sugarbeet as affected by genotypes at harvest treatments (variety) beet quality characters total soluble solids (tss %) or brix (%) sucrose percentage (%) apparent purity percentage (%) cs 0327 20.41 c 14.65 c 71.79 a cs 0328 21.52 a 15.50 a 72.04 a hi 0044 19.79 d 13.95 d 70.50 b hi 0473 20.65 bc 14.73 c 71.32 ab shubhra 21.04 b 15.03 b 71.41 ab cauvery 21.90 a 15.68 a 71.60 ab cv (%) 1.28 1.05 1.15 lsd(0.05) 0.40 0.24 1.23 in a column, figures with a similar letter do not differ significantly and those with dissimilar letter significant at 5% level. apparent purity percentage apparent purity percentage of tropical sugarbeet was significantly influenced by the different genotypes. the maximum apparent purity percentage (72.04 %) was obtained from cs 0328 followed by cs 0327 (71.79 %) and the lowest (70.50 %) purity percentage was appeared in genotype hi 0044. conclusion it may be concluded that among the six genotypes, cauvery showed the better performance in all aspect of yield and quality parameters of sugarbeet, except harvest index and apparent purity percentage followed by the genotype cs 0328 in all the studied charactyers. hence, the sugarbeet genotypes cauvery and cs 0328 could be selected for further evaluation under different field conditions before going for cultivation commercially in bangladesh. references abdel-motagally, f.m.f. and k.k. attia. 2009. response of sugarbeet plants to nitrogen and potassium fertilization in sandy calcareous soil. int. j. agric. bio. 11: 695-700. aly, e.f. 2006. effect of environmental conditions on productivity and quality of some sugarbeet varieties. ph. d. thesis. fac. of agric. benha univ., egypt. azzazy, n.b., n.m.s. shalaby and a.m. abd el-razek. 2007. effect of planting density and days to harvest on yield and quality of some sugarbeet varieties under fayoum condition. egypt. j. appl. sci. 22(12a): 101-14. badawi, m.a., m.a. el-agroudy and a.n. attia. 2003. effect of sowing dates and npk fertilization on growth and yield of sugarbeet (beta vulgaris l.). j. agric. sci. 20(6): 2683-2689. bairagi, a., s.k. paul, m.a. kader and m.s. hossain. 2013. yield of tropical sugarbeet as influenced by variety and rate of fertilizer application. pak. sugar j. 28(4): 15. yield and quality of some tropical sugarbeet genotypes 61 brac. 2010. project report on sugarbeet cultivation, bangladesh rural advancement committee, pp.13-16. bsri. 2011. sugarbeet cultivation in bangladesh. bangladesh sugarcrop research institute. ishurdi, pabna, bangladesh. p.4. david, d. and a. young. 1981. soil survey and land evaluation. george allen and unwin publishers ltd, 40 museum street, london wc1a 1lu uk. enan, s.a.a.m., s.r.e. el-sheikh and k.a.m. khaled. 2009. evaluation of some sugarbeet varieties under different levels of n and mo fertilization. j. agric. bio. chem. envir. sci. 4(1): 345-362. hossain, m.m., m.a. kader and m.a. kashem. 2011. effects of sowing date and variety on the yield of tropical sugarbeet (beta vulgaris l.). b. agro. j. 14(1&2): 95-101. islam, m.s., s. ahmad, m.g. uddin and m.a. sattar. 2012. evaluation of tropical sugarbeet genotypes under bangladesh condition. j. agric. res. 37(4): 721-728. jozefyova, l. 2004. effect of harvest time on sugarbeet fertilized with increased nitrogen. wfl publisher science and technology. food, agric. envir. 2(1): 232-237. lamani, k.d. and s.i. halikatti. 2019. performance of sugarbeet genotypes and date of sowing on yield and quality parameters. advan. res. 18(2): 1-7. doi: 10.9734/air/2019/46696. marlander, b. and i. rothe. 2005. zuckerrubenanbau im wandel der zeit-herausforderung, inovation und entwicklungspotencial. zuckerindustrie 130(6): 482-486. ntwanai, b. and s.w. tuwanai. 2013. effect of planting date on yield and sugar content of sugarbeet cultivars grown in cradock, eastern cape. african crop science conference proceedings 11: 5154. osman, a.m.h., g.s. el-sayed, m.s.h. osman and k.s. el-sogheir. 2003. soil application of some microelements with relation to yield and quality of sugarbeet varieties. ann. agric. sci., moshtohor, 41(3): 1071-1088. rahman, m.k. 2011. feasibility of sugarbeet cultivation in bangladesh: a review (handbook in bangali version). bangladesh sugarcrop research institute. ishurdi, pabna, bangladesh. pp.1-10. shahl, i.h., n.u. khanl, g. flasool and n. saeed. 2000. effect of sowing time and plant population on root yield and accumulation of sugar in sugarbeet. pak. j. bio. sci. 3(12): 2005-2007. statistix 10. 2013. analytical software. tallahassee, florida, usa. syngenta. 2004. syngenta bangladesh ltd. http// sugarbeet.ucdavis.edu/ sbpm/nutrients/ fig1. gif. www. sugarproducer.com, 2011. sugar producer magazine. ulakovic, v., n. glamoclija, v. filipovic and v. ugrenovic. 2015. mineral nutrition plants in function of stable sugarbeet production. selekcija i semenarstvo 21: 39-49. doi: 10.5937/selsem1502039d. bangladesh agron. j. 2021, 24(1): 37-42 influence of twig removal on yield and economics of pea varieties s.s. kakon, s.m.a.h.m. kamal1, m.a.k. mian, r.r. saha2 and m.a. hossain3 agronomy division, bangladesh agricultural research institute, joydebpur, gazipur 1breeder seed production centre, debigonj, panchaghor, bangladesh agricultural research institute 2oil seed research centre, bangladesh agricultural research institute, joydebpur, gazipur 3on-farm research division, bangladesh agricultural research institute, joydebpur, gazipur corresponding e-mail: kakonbari@gmail.com (received: 30 january 2020, accepted: 12 april 2021) keywords: twig removal, leafy vegetable, yield, bcr, pea abstract the experiment was conducted at the research field of agronomy division, bari, joydebpur, gazipur during rabi seasons of 2016-2017 and 2017-2018 to evaluate the effects of twig removal on yield and yield attributes, and extra benefit incurred due to removal of twig as a leafy vegetable in pea varieties. treatments consisted of three varieties such as v1=natore local, v2 = bari motorshuti-1 and v3= bari motor-1 and five twig removal variables, viz. t1= control (no removal), t2 = removal of 5 cm twig at 25 dae, t3= removal of 7.5 cm twig at 25 dae, t4=removal of 10 cm twig at 35 dae, t5= removal of 12.5 cm twig at 35 dae. leafy vegetable yield varied among the varieties and twig removal variables. the highest leafy vegetable yield (778 and 975 kgha-1) over the years was recorded in bari motorshuti-1 when 12.5 cm twig removed at 35 days after emergence which was at par with bari motor-1 at the same cutting time and the same length. the maximum pod yield (9.15 t ha-1 and 9.52 t ha-1) was recorded in bari motorshuti-1 when 5cm twig removed at 25 days after emergence (dae), which was statistically similar to the same variety with twig removal of 7.5 cm at 25 dae. the highest gross return (tk. 76522.00 ha-1), gross margin (tk.48272.00 ha-1) and bcr (2.71) was recorded in bari motorshuti-1 when twig removed 5 cm at 25 dae, which was similar to the same variety with 7.5 cm twig removed at 25 dae. the result revealed that 5-7.5 cm twig removal at 25 dae from the tip might be a profitable technique for pea (var. bari motorshuti-1) production for dual purpose as vegetables and pod yield. introduction pea (pisum sativum l.) is one of the most important leguminous vegetable crops grown during the winter season in bangladesh for local consumption. the crop is a major source of protein (21% 25%) with high levels of amino acids, lysine and tryptophan that have high nutritional value (bhat et al., 2013; gregory et al., 2016). pea is grown in an area of 10 379 535 hectares, with a total production of 10 979 946 tons in the world (fao, 2014). not only limited to human and animal food but field pea can be used in enhancing the soil fertility by using as green (brown) for manure and as cover crops (papnai and singh, 2011). in developing countries like bangladesh, animal source of protein being expensive, plant protein source can be a great alternative (bitew et al., 2015). it can play an 38 kakon et al. important role to overcome protein deficit. pea is grown mainly for getting young pod and uses tender green seeds as a vegetable. the crop has gained popularity for its short duration and high nutritive value. leaf of pea is tasty and nutritious. pea shoots are used as a green leafy vegetable and generally are a good source of several vitamins and minerals. it also has high sugar content (12%), vitamin a and c, calcium, phosphorus and a little bit of iron ndsu. pea contains 8687% of total digestible nutrients and containing 5-20% less trypsin inhibitors than soybean, which can be feed to livestock without further processing (ndsu, 2003). nevertheless, it is imperative to increase productivity in different agroecological zones by manipulating various agronomic practices. pea may produce some vegetables by clipping the growing shoot for human consumption in addition to its optimum yield. moreover, this pruning practice could produce more branching and thereby increase pod formation. saxena and sheldrake (1979) and agricar (1990) have also reported an increased chickpea yield due to clipping of the young shoot during vegetative growth. nipping produced a higher yield compared to control treatment giving the highest return to farmers as stated by sumarjit and sophia (2006). nipping is also found as an effective technique in encouraging flower production but reducing foliage production (albert, 2009). foliage nipping at the early stages of the crop could the increase number of branches while restricting profuse vegetative growth thereby promoting crop yield were stated by singh and diwakar (1995). some farmers have been practicing shoot clipping of pea in bangladesh especially in the ishurdi region. farmers not only removed twig at the vegetative stage but also twig removed at the flowering stage for vegetable purposes. but they do not follow the optimum time and length of shoot for clipping. twig removal practice does not require any tools and equipment; it can be done by hand picking and cost-effective practice for small farmers. in this context, the investigation was undertaken to assess the effect of twig removal on the yield (pod and vegetable) and yield attributes of pea for dual purposes. materials and methods the experiment was conducted at the research field of agronomy division, bangladesh agricultural research institute (bari), joydebpur, gazipur during two successive rabi seasons of 2016-2017 and 2017-2018. the soil of joydebpur belongs to the chhiata series under agroecological zone-28. the soil was slightly clay loam and acidic (ph 6.1). treatments consisted of three varieties such as v1=natore local, v2= bari motorshuti-1 (garden pea) and v3= bari motor-1 (field pea) and five twig removal variables, viz. t1= control (no removal), t2= removal of 5 cm twig at 25 dae, t3= removal of 7.5 cm twig at 25 dae, t4=removal of 10 cm twig at 35 dae, t5= removal of 12.5 cm twig at 35 dae. the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 3 m 3 m. seeds of pea varieties were sown on 27 november in both years. fertilizers were applied at the rate of 35-2025-10 kg ha-1 of n-p-k-s (frg, 2012) in the form of urea, triple super phosphate (tsp), muriate of potash (mop) and gypsum. half of the urea, the whole amount of tsp, mop and gypsum was applied as basal. the remaining urea was top-dressed at 35 days after emergence (dae). the fresh leafy vegetable yield was recorded as per treatment imposition and pod yield was taken from the whole plot. at a later stage of the cropping season, rust disease was visible, then @ (tilt) 0.5 mll-1 was sprayed to control it. the crop was harvested on 22 february 2017 and 27 february 2018. data on yield and yield components were collected from the whole plot before harvest. collected data were analyzed statistically and means were separated by lsd(0.05). influence of twig removal on yield and economics of pea 39 results and discussion the yield of removed a twig as a leafy vegetable varied by the interaction of variety and twig removal of pea (fig. 1) in both years. the maximum vegetable yield over the years (778 and 975 kg ha-1) was recorded in bari motorshuti-1 when 12.5 cm twig removal at 35 days after emergence which was at par with that of bari motor-1 at the same cutting time and the same length. the lowest vegetable yield was recorded in all the varieties with twig removal of 5 cm at 25 days after emergence. v1=natore local, v2 = bari motorshuti-1 and v3= bari motor-1and and five twig removal t1= control (no removal), t2= removal of 5 cm twig at 25 dae, t3= removal of 7.5 cm twig at 25 dae, t4=removal of 10 cm twig at 35 dae, t5= removal of 12.5 cm twig at 35 dae fig. 1. leafy vegetable yield of pea as influenced by variety and twig removal during 2016-17 and 2017-18. plant height, yield and yield contributing characters plant height, yield and yield contributing characters of pea were significantly influenced by the interaction of variety and twig removal (table 1). twig removal significantly reduced plant height in all the varieties. the tallest plant (98.27 cm and 110.63cm) over the years were recorded in v1t1 (no removal with natore local) treatment and the shortest plant (36.10 and 38.70 cm) in v2t5 (twig removal of 12.5 cm at 35 dae with bari motorshuti-1) over the years. these results were supported by aslam et al. (2008) who explained that vigorous cutting of chickpea was positively related to the production of the tallest plants. the highest number of branches plant-1 (3.23 and 3.35) was recorded in v1t3 (twig removal of 7.5 cm at 25 dae with natore local) treatment which was followed by v1t2 treatment and the lowest (1.30 in 2016-17 and 1.58 in 2017-18) was recorded in v2t5 (twig removal of 12.5 cm at 35 dae with bari motorshuti-1). the maximum number of podsplant-1 (12.90 and 14.30) was found in v2t2 (twig removal of 5 cm at 25 dae with bari motorshuti-1) which was statistically similar to that of 0 200 400 600 800 1000 1200 l e a fy v e g .y ie ld (k g h a -1 ) treatments 2016-17 2017-18 40 kakon et al. v2t3 treatment while the lowest in v3t5 treatment (7.03 and 7.28) in both the years. an increase in auxiliary branches might be due to apical dominance exerted by the accumulation of cytokine in over auxin (agrikar, 1990). this result indicated that there was a significant positive effect of twig removal on lateral growth and pod yield. similar findings were observed by saxena and sheldrake (1979), who reported that clipping of the young shoot during vegetative growth caused an increase in auxiliary branches, which resulted in increased seed yield. higher pod yield (9.14 tha-1 and 9.52 tha-1) was recorded in v2t2 treatment which was at par with v2t3 treatment. higher yields were attributed due to the cumulative effect of the number of branches plant-1 and number of podsplant-1. the lowest pod yield over the years (3.08 tha-1and 3.28 tha-1) was recorded in v1t5. these results indicated that clipping length from the tip was the main determinant influencing yield. it was observed that 5-7.5 cm length from the tip at 25 dae was the optimum for clipping length to obtain the dual advantage of fresh leafy vegetables and pod yield. the results indicated that twig removal of 5-7.5 cm length from the tip at 25 dae performed better as compared to other treatments in terms of pod yield along with an additional leafy vegetable. this result showed close similarity with the findings of sumarjit and sophia (2000). significant reduction in the number of branches plant-1 and pods plant-1 was observed when 10.0 cm and 12.5 cm twig was removed from the tip at 35 dae, which resulted in lower pod yield but provided the highest leafy vegetables. similar results were obtained by khan et al. (2006). table 1. plant height, yield attributes and yield of pea as influenced by variety and twig removal during rabi seasons (2016-2017 and 2017-2018) treatment plant height (cm) branches plant-1 (no.) pods plant-1 (no.) pod yield (tha-1) 20162017 20172018 20162017 20172018 20162017 20172018 20162017 20172018 v1t1 98.27 110.63 3.16 3.19 8.27 8.86 4.31 4.63 v1t2 88.70 97.70 3.20 3.33 8.51 9.04 4.48 4.76 v1t3 81.00 94.00 3.23 3.35 8.35 8.78 4.38 4.56 v1t4 76.73 85.97 3.17 3.23 7.85 8.08 3.29 3.74 v1t5 71.30 78.97 2.80 3.15 7.04 7.58 3.08 3.30 v2t1 51.03 53.37 1.41 1.70 12.80 14.16 8.32 8.55 v2t2 49.17 52.50 1.60 1.74 12.90 14.30 8.62 8.84 v2t3 47.27 51.27 1.66 1.76 12.47 14.05 8.33 8.68 v2t4 44.83 45.83 1.54 1.67 11.11 13.02 7.27 8.01 v2t5 36.10 38.70 1.30 1.58 9.76 11.67 5.93 6.58 v3t1 78.07 86.07 1.47 1.62 10.67 11.01 5.10 5.25 v3t2 75.50 79.20 1.48 1.66 10.32 10.82 5.12 5.46 v3t3 68.30 71.63 1.52 1.71 9.98 10.45 5.04 5.28 v3t4 65.70 69.03 1.44 1.62 8.05 8.28 4.22 4.74 v3t5 55.97 59.30 1.31 1.59 7.03 7.28 4.04 4.24 lsd(0.05) 5.93 7.47 0.09 0.074 0.83 0.48 0.61 0.053 cv(%) 4.95 6.78 6.61 4.53 5.10 6.23 6.55 4.05 v1=natore local, v2 = bari motorshuti-1 and v3= bari motor-1and and five twig removal t1= control (no removal), t2= removal of 5 cm twig at 25 dae, t3= removal of 7.5 cm twig at 25 dae, t4=removal of 10 cm twig at 35 dae, t5= removal of 12.5 cm twig at 35 dae. cost benefits analysis average over the years, the highest gross return (tk. 90311 ha-1), gross margin (tk. 57061 ha-1) and benefit-cost ratio (2.72) were obtained from v2t2 treatment (bari motorshuti-1 with influence of twig removal on yield and economics of pea 41 twig removal of 5 cm at 25 dae) followed by v2t3 treatment (bari motorshuti-1 with twig removal of 7.5 cm at 25 dae). these results indicated that twig removal provided a higher gross return, gross margin, and benefit-cost ratio than that of the control (table 2). higher monetary returns obtained from those treatments might be due to higher yield and vegetable yield for twig removal. similar results were also obtained by ali et al. (2000) who found that the shoot picking system gave higher total production, gross return, gross margin, and benefit-cost ratio. the results revealed that twig removal of 5-7.5 cm at 25 dae might be economically profitable for the dual purpose of pea production. it was noted that the crop was partially affected by rust disease before harvest that resulting in poor yield as well as gross margin and bcr in all treatments in the study. table 2. cost and return analysis of twig removing in pea varieties (average of 2016-2017 and 2017-2018) treatments pod yield (tha-1) leafy veg. yield (kg ha-1) gross return (tk. ha-1) cost of production (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio v1t1 4.47 0.00 44700 27020 19680 1.65 v1t2 4.62 297.11 48577 27830 23047 1.75 v1t3 4.47 473.64 48489 28830 22959 1.68 v1t4 3.52 592.19 39888 28960 13628 1.38 v1t5 3.19 768.60 38049 28960 11789 1.31 v2t1 8.35 0.00 83500 32880 50620 2.54 v2t2 8.73 376.40 90311 33250 57061 2.72 v2t3 8.51 525.12 89251 33250 56001 2.68 v2t4 7.64 725.14 82201 32650 53551 2.52 v2t5 6.26 876.83 69565 32650 40915 2.13 v3t1 5.18 0.00 51750 29580 26170 1.75 v3t2 5.29 345.70 55666 29960 25706 1.86 v3t3 5.16 512.20 55698 31360 24338 1.78 v3t4 4.48 692.92 50343 31360 18983 1.61 v3t5 4.14 865.27 48322 31360 16962 1.54 v1=natore local, v2=bari motorshuti-1 and v3=bari motor-1and and five twig removal t1=control (no removal), t2= removal of 5 cm twig at 25 dae, t3= removal of 7.5 cm twig at 25 dae, t4=removal of 10 cm twig at 35 dae, t5= removal of 12.5 cm twig at 35 dae. market price (tk/kg): fresh pod 10/-, leafy vegetable 8/ conclusion in conclusion, twig removing was found to influence significantly in enhancing the productivity of pea. twig removing practice done before or at 30 days was found to be profitable. as twig removing plays a significant role in branching, twig removed plots gave superior results over controlled treatments. from two years study it is revealed that twig removal of 5-7.5 cm at 25 dae of bari motorshuti-1 would be appropriate for obtaining higher pod yield as well as leafy vegetable yield. 42 kakon et al. references agricar, g.p. 1990. gram. in: pulse crops of india. icar, new delhi, india pp.54-136. albert, s. 2009. pea growing problems: troubleshooting. harvest to table. ali, m.a., s.s. zaman, m.a. karim, m.a. mannan and m.f. islam. 2000. effect of shoot picking on the agro-economic performance of chickpea. bangladesh j. agril. res.25(2): 261-267. aslam, m., a.h. khalil, k. himayatullah, m. ayaz, m. ejaz and m. arshad. 2008. effect of available soil moisture depletion levels and topping treatments on growth rate and total dry biomass in chickpea. j. agri. res.46(3): 229-243. aziz, m.a. 2000. response of chickpea to nipping.pakistanj.sci.indus.res.43(3):191-192. bhat, t.a., m. gupta, m.a. ganai, r.a. ahanger and h.a. bhat. 2013. yield, soil health and nutrient utilization of field pea (pisum sativum l.) as affected by phosphorus and biofertilizers under subtropical conditions of jammu. intl. j. m. plant anim. sci.1(1):1-8. bitew, y., f. asargew and g. chakelie. 2015. evaluation of intra and inter row spacing on the seed yield and yield component of field pea (pisum sativum l.). j.afrikana.2(2):1–15. fao. 2014.http://faostat.fao.org/site/567/desktopdefault.aspx?p=567. gregory, e., f. shana, k. hans, p. julie, w. michael, k. janet and h. kenneth. 2016. field pea production a1166 (revised). north dakota state university, extension service. khan, h., a. latif, s. mahmood and m.s.s. khan. 2006. effect of nipping at various stages on yield and yield components of chickpea (cicer arietinum l.). j. res. sci. bahauddin zakariya university, multan, pakistan. ndsu. 2003. field pea production. north dakota state university, usa,pp.1-83. papnai, g. and n.p. singh. 2011. applied horticulture: crop production technology (vegetable crops). india: uttarakhand open university. pp.1-15. saxena, n.p. and a.r. sheldrake. 1979. physiology of growth, development and yield of chickpea in india. in: proceedings of international workshop on chickpea improvement. 28fe.-mar 1979. icrisat. hyderabad, india, p.106. singh, h. and b. diwakar. 1995. chickpea a botany and production practices. icrsat. skill development series no.16. sumarjit, s.m. and d.k. sophia. 2006. profitability of nipping in cultivation of pea (pisum sativum)– an indigenous agro-technique in manipur. indian j. agron. 51(3): 206-208. https://www.harvesttotable.com/pea_growing_problems_troublesh/ http://www.academia.edu/17452563/evaluation_of_intra_and_inter_row_spacing_on_the_seed_yield_and_yield_component_of_field_pea_pisum_sativum_l._ http://www.academia.edu/17452563/evaluation_of_intra_and_inter_row_spacing_on_the_seed_yield_and_yield_component_of_field_pea_pisum_sativum_l._ http://agresearch.montana.edu/wtarc/producerinfo/agronomy-nutrient-management/pulses/ndsufactsheet.pdf http://agresearch.montana.edu/wtarc/producerinfo/agronomy-nutrient-management/pulses/ndsufactsheet.pdf bangladesh agron. j. 2021, 24(2): 109-113 growth and yield of chickpea as affected by detopping time and height m.s. kobir*, m.o. ali, m.j. hossain, m.s. alam, s. paul, p. hajong and m. h. rahman bangladesh agricultural research institute, bangladesh *corresponding email: shahriar1302027@gmail.com (received: 04 october 2021, accepted: 09 december 2021) keyword: de-topping, nipping, chickpea, time, height, yield abstract the production area of chickpea in bangladesh is decreasing day by day due to the competition with higher yielding crop which is/or profitable than chickpea. as such, the experiment was undertaken at regional agricultural research station, jashore during 2019-2020 and 2020-2021 to study the effect of most suitable method of de-topping (nipping) in chickpea (var. bari chola-10) for its growth and yield improvement. treatments were imposed in a split-plot design where in main plot : time of nipping : 30 days after emergence (dae) , 40 dae e350 dae and in sub-plot: different heights of nipping practices: control, nipping 5 cm from growing tip, nipping 8 cm from growing tip and nipping 10 cm from growing tip. in interaction treatment, the highest days to flower (68), days to mature (112), vegetable yield (703 kg ha-1) was observed when chickpea plants were de-topped after 50 dae at 10 cm from growing tip. the highest plant height (46 cm) was observed when de-topping at 40 dae was done at 10 cm from growing tip. seed yield (1419.95 kg ha-1) and marginal benefit cost ratio (mbcr) (13.1) was recorded maximum when chickpea plants de-topped 50 dae at 5 cm from growing tip. de-topping practices in chickpea (var. bari chola-10) after 50 dae at 5 cm from growing tip could maximize the productivity of chickpea. introduction per capita availability of pulses is very low against per capita demand due to back drop of pulses production (azad et al., 2019). among the pulse crops chickpea is one of the most important pulses crop in bangladesh as it contains protein (%) in almost half of its’ individual seed weight. bangladesh has to import a huge amount of chickpea each year due to its huge shortage against demand of production. removal of apical meristem (apical dominance of auxin) is termed as de-topping / nipping (khan et al., 1993) which promotes the emergence lateral branches due to role of cytokinins (campbell et al., 2008). the more the lateral branches the more the flower initiating points that increases yield. number of branches followed by more pods are the resulted effect of de-topping at various stages of plant growth that boost the grain yield of chickpea (aziz, 2000; aslam et al., 2008). severity of diseases are reduced and yield is increased in case of de-topping at 45 days after sowing (sumarjit and sophia, 2006). in addition, de-topped chickpea leaves are a good source of fodder (zahid et al., 1997). so, this experiment was undertaken to study the effect of de-topping practice along with its time and find out suitable de-topping management in chickpea (var. bari chola-10) for yield improvement. materials and methods the experiment was conducted in the regional agricultural research station, bangladesh agricultural research institute, jashore during rabi season of 2019-20 and 2020-21. the latitude, longitude and altitude of this site is 23018’ n, 89018’ e and 19 m, respectively (kobir et al., 2020). the site belongs to aez-11 n ‘high ganges river floodplain’ (bbs, 2019).the soil of the experimental field was sandy clay-loam in texture with medium high land. treatments were imposed in a split-plot design where in main plot : time of de-topping/ nipping (03): i) e130 days after emergence (dae) ii) e240 mailto:shahriar1302027@gmail.com 110 kobir et al. dae iii) e350 dae an in sub-plot different heights of nipping practices (04): t1control, t2 nipping 5 cm from growing tip, t3nipping 8 cm from growing tip, t4nipping 10 cm from growing tip. . the chickpea var. bari chola-10 was used. fertilizers were given as basal as n, p2o5, k2o, s and b @ 20, 40, 20, 20, 1 kg ha-1, respectively. different parameters on growth, yield components and yield of chickpea were studied. data were tabulated by microsoft excel software and data were analyzed by statistical software “r” packages. results and discussion results revealed that treatment nipping had significant influence on plants m-2, days to flower, days to maturity, plant height, pods plant-1, vegetable production ha-1 and seed yield ha-1 (table 1). nipping at 40 dae showed maximum t values of days to maturity, pods plant-1, branches plant-1, seed yield and followed by nipping at 50 dae but only vegetable yield was highest with later nipping and followed by 10 days earlier this practice. nipping 30 dae was proved comparatively lower in each parameter. table 1. growth and yield of chickpea as affected by nipping (pooled over the years) treatments plants m-2 (no.) days to flowering (no.) days to maturity (no.) plant height (cm) pods plant-1 (no.) branches plant-1 (no.) vegetable production (kg ha-1) seed yield (kg ha-1) e1 22 62 114 42 21 2 123 663 e2 32 64 116 44 28 3 212 1201 e3 38 65 115 39 26 3 385 1150 cv (%) 6.98 1.25 0.75 11.45 17.35 12.20 19.68 18.00 lsd(0.05) 2.13 0.77 0.91 2.97 3.89 ns 55.63 242.68 e1-30 days after emergence, e2-40 days after emergence, e3-50 days after emergence plants m-2, days to flower, vegetable production ha-1 and seed yield ha-1 were significantly varied due to nipping point when days to maturity, plant height, pods plant-1, branches plant-1 did not response with the practice (table 2). table 2. growth and yield of chickpea as affected by different height of nipping (pooled over the years) treatments plantsm -2 (no.) days to flowering (no.) days to maturity (no.) plant height (cm) pods plant-1 (no.) branches plant-1 (no.) vegetable production (kg ha-1) seed yield (kg ha-1) t1 31 63 115 43 25 3 0 894 t2 30 64 115 41 28 3 223 1150 t3 30 64 115 43 25 3 283 1068 t4 33 65 115 41 22 3 455 974 cv (%) 6.96 1.37 0.61 7.46 26.91 15.39 14.54 14.10 lsd(0.05) 2.1 0.84 ns ns ns ns 57.59 232.00 t1control, t2nipping 5 cm from growing tip, t3nipping 8 cm from growing tip, t4nipping 10 cm from growing tip nipping 10 cm growing tip gave maximum plants m-2, days to flower, vegetable production ha-1 and at par with other nipping times but vegetable yield was obtained highest with de-topped 10 cm tip. numerically greater number of pods plant-1 was registered with nipping 5 cm growing tip, that treatment increased seed yield maximum and followed by 8 and 10 cm nipping. treatment no nipping (control) had no additional vegetable yield and poor seed yield thus knocking at nipping practices. in case of combined effect, the highest plant height was found when chickpea plants de-topped after 40 days of emergence at 10 cm from growing tip and the lowest plant height was found when chickpea plants were de-topped after 50 days of emergence at both 10 cm and 5 cm from growing tip. when chickpea plants were de-topped in 40 days after emergence at 10 cm from growing tip, the plants get growth and yield of chickpea as affected by de-topping time and height 111 adequate days to attain highest apical height which is not possible when chickpea were de-topped in 50 days after emergence. aslam et al. (2008) however pointed out that vigorous cutting of chickpea plants is related to tallest plant. the highest plants m-2, days to flower and days to mature was recorded when chickpea plants de-topped 50 dae at 10 cm from growing tip. on the other hand, the lowest plants m-2, days to flower and days to mature was observed when chickpea plants de-topped after 30 dae at 5 cm from growing tip, not de-topped at 30 dae, respectively (table 3). gaudreau et al. (2020) claimed that de-topping in later stage of vegetative growth, the auxiliary inflorescence can only initiate after the recovery period which can delay the overall growth of the plant thus maturity gets later. but de-topping in early stage of vegetative growth, the plants can get adequate days to flower after recovering from pruning. the highest branches plant-1 was found when chickpea plants were not de-topped at 40 days after emergence and the lowest branches plant-1was found when chickpea plants were de-topped after 30 days of emergence at 10 cm from growing tip. the highest pods plant-1 was found when chickpea plants de-topped after both 40 and 50 days of emergence at 5 cm from growing tip and the lowest pods plant-1was found when chickpea plants were de-topped after 30 days of emergence at 10 cm from growing tip (table 3). table 3. combined effect of nipping time and height on phenology of chickpea (pooled basis of two year) combined treatment plants m-2 (no.) days to flowering (no.) days to maturity (no.) plant height (cm) pods plant-1 (no.) branches plant-1 (no.) e1t1 28 57 112 41.5 23 3 e1t2 16 62 114 41.5 21 3 e1t3 18 62 114 42.5 21 2 e1t4 23 64 115 40 15 2 e2t1 28 60 114 45 26 3 e2t2 31 63 115 42 30 3 e2t3 33 65 116 45.5 26 3 e2t4 34 65 117 44.5 28 3 e3t1 35 60 113 41 24 3 e3t2 38 64 114 38 30 3 e3t3 38 65 116 39 27 3 e3t4 41 67 118 38 21 3 cv (%) 6.96 1.37 0.61 7.46 17.91 15.39 lsd(0.05) 3.79 1.48 1.68 5.95 10.66 0.70 e1-30 days after emergence, e2-40 days after emergence, e3-50 days after emergence, t1control, t2nipping 5 cm from growing tip, t3nipping 8 cm from growing tip, t4nipping 10 cm from growing tip in the pooled basis of analysis, the highest vegetable yield was found from de-topping after 50 days of emergence at 10 cm from growing tip and the lowest vegetable yield was found when chickpea crops not de-topped in 30, 40 and 50 days after emergence (figure 1). the highest seed yield was found from de-topping after 50 days of emergence at 5 cm from growing tip and the lowest seed yield was found when chickpea crops were not de-topped in 30 days after emergence (figure 1). this may be happened due to light nipping at certain period of time can enhance plant height, branches plant-1, pods plant-1, days to flower as well as days to mature, those lead to increase in seed yield. aslam et al. (2010) reported that removal of 2 cm from growing tip at 70 days after sowing gave the highest seed yield and the lowest seed yield was found in control. similar trend also found by even and wahab (1983) and othman and wan (1987). 112 kobir et al. e1-30 days after emergence, e2-40 days after emergence, e3-50 days after emergence, t1control, t2nipping 5 cm from growing tip, t3nipping 8 cm from growing tip, t4nipping 10 cm from growing tip fig.1. combined effect of nipping time and height on vegetable and grain yield of chickpea. cost analysis: partial cost analysis of chickpea de-topping showed that the highest total additional taka over control and marginal benefit cost ratio achieved when chickpea crops was de-topped in 50 dae at 5 cm from growing tip (e3t2). the lowest total additional taka over control and marginal benefit cost ratio calculated when chickpea crops were de-topped in 30 days after emergence at 5 cm from growing tip (e1t2) (table 4). table 4. partial cost analysis of different treatment combinations (2019-20 and 2020-21) combined treatment total add. tk. over control cost of treatment mbcr 2019-20 2020-21 mean 2019-20 2020-21 mean 2019-20 2020-21 mean e1t1 e1t2 9988.8 8420 9204.4 3600 3600 3600 2.7 2 2.3 e1t3 25216.0 23580 24398 4800 4800 4800 5.2 5 5.1 e1t4 21195.3 19550 20372.6 7000 7000 7000 3.0 3 3.0 e2t1 e2t2 34041.6 32450 33245.8 3600 3600 3600 9.4 9 9.2 e2t3 34041.6 25595 29818.3 4800 4800 4800 7.0 7 7.0 e2t4 37147.4 35180 36163.7 7000 7000 7000 5.0 5 5.1 e3t1 e3t2 51612.2 44755 48183.6 3600 3600 3600 14.3 12 13.1 e3t3 34151.5 30900 32525.7 4800 4800 4800 7.1 6 6.5 e3t4 41966.6 38665 40315.8 7000 7000 7000 5.9 6 5.9 e1-30 days after emergence, e2-40 days after emergence, e3-50 days after emergence, t1control, t2nipping 5 cm from growing tip, t3nipping 8 cm from growing tip, t4nipping 10 cm from growing tip, mbcr=marginal benefit cost ratio input price: (tk./ kg) urea-16 -1, tsp-22 1, mop-15 1, gypsum-06, power tiller (1 pass): tk. ha-1 2250 1, irrigation tk. kg-1 (1 time): 900, labor: tk. day-1 400 08 hours-1, tk. kgchickpea seed-120 1 output price: tk. / kg : chickpea-70 1, vegetable-55 conclusion from the above findings, it can be concluded that growth and yield of chickpea is affected by detopping practice. seed yield was maximum when chickpea plant (var. bari chola-10) is de-topped after 50 dae (days after emergence) at 5 cm from growing tip followed by highest marginal benefit cost ratio. growth and yield of chickpea as affected by de-topping time and height 113 references aslam, m., a.h. khalil, k. himayatullah, m. ayaz, m. ejaz and m. arshad. 2008. effect of available soil moisture depletion levels and topping treatments on growth rate and total dry biomass in chickpea. j. agri. res. 46(3): 229-243. aslam, m., e.a. khan, himayatullah, m. ayaz, h.k. ahmad, m. mansoor and k. hussain. 2010. effect of soil moisture depletions and de-topping on yield and yield components of chickpea. j. agri. res. 26(2): 177-186. azad, a.k., a. wahab, m.g. saha, z. nesa, m.l. rahman, h.h. rahman and l. amin. 2019. krishi projukti hatboi (handbook on agro-technology), 8th edition. bangladesh agricultural research institute, gazipur-1701, bangladesh: 47, 64, 67. aziz, m.a. 2000. response of chickpea to nipping. pakistan j. sci. indus. res. 43(3): 191-192. bbs (bangladesh bureua of statistics). 2019. yearbook of agricultural statistics-2018, p.08. campbell, n.a., j.b. reece, l.a. urry, m.l. cain, s.a. wasserman, p.v. minorsky and r.b jackson. 2008. biology (8th ed.) pearson benjamin cumming. san francisco and london: pp.827-830. even, e.j. and a.g wahab. 1983. effect of leaf removal on the growth of winter oil seed rape (brassica napus l.). proc. 6th int’l. rapeseed cong. paris. 17-19 may, 1: 104-109. gaudreau, s., t. missihoun and h. germain. 2020. early topping: an alternative to standard topping increases yield in cannabis production. plant sci. today. 7(4): 627–630. https://doi.org/10.14719/pst.2020.7.4.927. khan, r.u., h.h. muendel and m.f. chaudhry. 1993. effect of topping and ratooning on seed yield and fodder production of rape seed (brassica napus l.). agron. trend agric. sci. 1: 17-23. kobir, m.s., m.h. rashid and s. ahmed. 2020. development of integrated fertilizer management strategies in lentil for higher productivity in the south-western region of bangladesh. agril. sci. 2(1): 275281.https://doi.org/10.30560/as.v2n1p275. merga, b. and j. haji. 2019. economic importance of chickpea: production, value, and world trade, cogent food & agriculture. 5 (1): 161. https://doi.org/10.1080/23311932.2019.1615718. othman, m. and wan. 1987. the effects of height and frequency of previous defoliation on nodulation, nitrogen fixation and regrowth of phasey bean agris record fao of the united nations. 10(1): 110. sumarjit, s.m. and d.k. sophia. 2006. profitability of nipping in pea (pisum sativum l.) an indigenous agro-technique in manipur. indian. j. agron. 51: 206-208. zahid, m.s., m.u. mufti, s. khan and m.b. bhatti. 1997. impact of improved varieties and production technology in improving the existing fodder production systems under the medium rainfall areas of fatehjang (attock district). sarhad j. agric. 13: 517-525. https://doi.org/10.30560/as.v2n1p275 https://doi.org/10.1080/23311932.2019.1615718 conclusion references bangladesh agron. j. 2022, 25(1): 115-128 germination and growth performance of seedlings of ascorbic acid, silicon and gibberellic acid treated secondary seed of wheat under salt stress s. islam1, p.k. biswas1, a.k.m.r. amin1, m. fujita2, a.k. paul3, j.a. mahmud4 and m. hasanuzzaman1 1department of agronomy, 3department of soil science, 4department of agroforestry and environmental science, shere-bangla agricultural university, dhaka-1207, bangladesh 2department of applied biological science, kagawa university, kagawa 761-0795, japan corresponding e-mail: parimalbiswas@hotmail.com (received: 16 june 2022, accepted: 23 june 2022) keywords: wheat, salt stress, ascorbic acid, silicon, gibberellic acid abstract considering the effect of salt stress on morph-physiological and biochemical changes of wheat (triticum aestivum l. var. bari gom-26) as well as mitigation of the adverse effect through exogenous application of ascorbic acid (asa), silicon (si) and gibberellic acid (ga3), the experiment was conducted at department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh. in the field experiment, four levels of salt stress (0, 50, 80, 120 mm nacl) were applied at 20 days after sowing and grown up to harvest. asa (2 mm ascorbic acid), si (200 µm sio2), ga3 (100 µm gibberellic acid) were applied as foliar spraying at 20 days interval. seeds were collected from the field experiment which used as secondary seeds as planting materials for second experiment to evaluate the influence of asa, si and ga3 on growth performance and physiological attributes of seedlings under salt stress. experiment revealed that asa, si and ga3 enhanced the germination and growth performance of seedling under salinity stress. overall, ga3 significantly increased the seed germination (%) and seedling growth parameters, while silicon mostly improved the fresh weight and chlorophyll (a, b and a+b) and asa showed better relative water contents with other parameters. considering the results of experiments, ga3 performed better than the asa and si in mitigating salt stress. introduction among abiotic stresses, salt stress is one of the critical determinants limiting crop production (wassmann et al., 2009). about 20% of the world total agricultural areas are affected by salinity (fao, 2015). it is expected that, by the middle of the twenty-first century, 50% of the world’s arable area will be influenced by salinity (machado and serralheiro, 2017). saline conditions crucially influence various plant development phases; germination and early seedling are acknowledged as more delicate growth stages in most plant species (ibrahim et al., 2016). higher salinity induced both ionic and osmotic stresses in the plant that causes growth inhibition, yield reduction and even death of the plant (hasanuzzaman et al., 2013; nahar et al., 2016). the immediate response of plants to higher salinity is osmotic stress that reduces cell expansion, cell division, and stomatal closure consequently inhibits leaf area, photosynthesis and growth of the plant. in the later stage, plants experience ionic stress due to the accumulation of na+ and cl‒ at the toxic level. higher accumulation of na+ causes premature senescence of adult leaves by disrupting protein synthesis and interfering with enzyme activity (wu and wang, 2012; rahman et al., 2016a). salt-induced osmotic stress, ionic toxicity and a lower rate of photosynthesis increase the production of reactive oxygen 116 islam et al. species (ros). a higher composition of ros interrupts the antioxidant defense system and hence causes oxidative stress (hasanuzzaman et al., 2013). mitigation of abiotic stress including salinity by using antioxidants is one of the common approaches for plant biologists in recent times. the antioxidants including ascorbic acid (asa), play a significant role in the mitigation of additional cellular reactive oxygen species function caused by salinity stresses (venkatesh and park, 2014). reduced ascorbic acid (asa) is the non-enzymatic antioxidant component that plays a vital role in the asa-gsh cycle. as an efficient electron donor, asa directly reacts with ros (hasanuzzaman et al., 2011). enhanced synthesis of asa plays a crucial role in conferring stress tolerance by detoxifying ros and maintaining other antioxidants gsh, α-tocopherol etc (de tullio et al., 2004). the effect of plant elements in mitigating the effect of abiotic stress in plants including salinity has become a matter of interest in recent decades. among them, silicon (si) is the second most abundant element in the soil. although it is a non-essential element, it has some beneficial role for plant growth and development. the beneficial role of si plays a role against various abiotic stresses (srivastava et al., 2015). silicon reduces na+ uptake acting as a mechanical barrier. accumulation of si by plant reduces transpiration through deposition in the cell wall of leaves which decreases na+ uptake and transpiration. also, si application improves salt stress tolerance by improving the water status of the plant (wang et al., 2015). moreover, si mitigates salt-induced oxidative stress by detoxifying ros by regulating the antioxidant defense system (zhu and gong, 2014). of the plant hormones, gibberellic acid (ga3) helps enhance plant growth and development under abiotic stress conditions (ryu and yong-gu, 2015). the exogenous application of ga3 developed sufferance under abiotic stress by induction and developing of the endogenous levels of salicylic acid (alonsoramírez et al., 2009). moreover, seed priming with ga3 alleviate the drastic effect of salinity and increase grain weight and grain quality by improving photosynthetic pigments, leaf area and plant growth (shaddad et al., 2013). foliar applications of ga3 also confer salt stress tolerance by increasing germination percentage, plant growth and up regulating antioxidant enzyme (tabatabei, 2013). a different study showed that ga3 has a significant outcome on various of the biological processes that happen in plants, before-mentioned as better germination percentage in various plants under natural circumstance (al sahil, 2016). although many studies revealed the mechanisms, by which asa, si and ga3 alleviate salt stress through ionic and osmotic homeostasis, regulating antioxidant defence and another biochemical process, it was necessary to further study to understand the mechanisms how they alleviate salt-induced damages in wheat. materials and methods plant materials and growth conditions the experiment was conducted at plant physiology laboratory, sher-e-bangla agricultural university, dhaka (90°77´ e longitude and 23°77´ n latitude) during october to december, 2018. wheat (triticum aestivum l. var. bari gom-26) seeds were collected from the previous experiment where ascorbic acid (2 mm), silicon (200 µm sio2) and gibberellic acid (100 µm)were exogenously applied under different level of salt stress (0, 50, 80 and 120 mm nacl). the collected seed of the previous experiment was named as secondary seed. the secondary seed of bari gom-26 were surface sterilized with 70% ethanol for 8–10 min for sterilization. seeds were rinsed several times with distilled running water. fifty seeds were sown in hydroponic plates with 250 ml of distilled water. the growth performance and physiological attributes data were collected from 10 days old seedling. germination (%) a germination test was carried out in the plant physiology laboratory. fifty seeds were soaked in water for one hour then spread on a layer of moistens filter paper in the petri dish. the lid was put on performance of wheat seedlings under salt stress 117 the petri dish and placed in the dark room and recorded the number of seeds that germinate daily. germination % was determined by using the following formula: germination % = (seeds germinated / total seed) × 100 measurement of fresh and dry biomass, relative water content and chlorophyll (chl) content for fresh weight (fw) and dry weight (dw) measurement, 10 seedlings from each treatment were selected and uprooted carefully, weighed and deliberated as fw. dw was determined after drying the seedlings at 80 °c for 48 h. leaf relative water content was measured in accordance with barrs and weatherly (1962). leaf laminas were weighed (fw) then placed immediately between two layers of filter paper and submerged in distilled water in a petri dish for 24 h in a dark place. turgid weight (tw) was measured after gently removing excess water with a paper towel. dry weight was measured after 48 h oven drying at 70 °c. leaf relative water content (rwc) was determined by using the following formula: rwc (%) = (fw−dw) / (tw−dw) × 100 chlorophyll (chl) content was measured as a fresh leaf sample of 0.25g was taken from randomly selected seedlings to measure the chlorophyll content. the samples were homogenized with 10 ml of acetone (80% v/v) using pre-cooled pestle and mortar and the homogenate was centrifuged at 10,000 × g for 10 min. the absorbance of the supernatants was measured with a uv visible spectrophotometer at 663 and 645 nm for chl a and chl b respectively. the amount of chlorophyll contents was calculated using the equations suggested by arnon (1949). chlorophyll a (μg/ml) = 12.7 (a663) 2.69 (a645) chlorophyll b (μg/ml) = 22.9 (a645) 4.68 (a663) total chlorophyll (μg/ml) = 20.2 (a645) + 8.02 (a663) shoot and root length seedlings were taken randomly and shoot-root length was measured in centimeters with the scale. root shoot ratio length basis root-shoot ratio was calculated by following the method of khandakar (1980) to estimate root efficiency to support production. root length root-shoot ratio (%) = × 100 shoot length vigor index seedling vigor index was calculated by using by the formula of abdul-baki and anderson (1973). vigor index (vi) = germination (%) × seedling length (cm) survivability (%) number of servable seedling survivability (%) = × 100 total number of seed statistical analysis the data obtained for different parameters, mean values of each parameter were calculated and subjected to based costat v.6.400 (costat, 2008) software. the average of three replications (n = 3) was used to determine mean (± sd) for each treatment and mean differences were compared using lsd (0.05) test. 118 islam et al. results and discussion germination percentage in this study, germination percentage significantly increased in secondary seed with previously exogenous application of ga3 under minimal or no salt stresses (0 mm and 50 mm) (figure 1). neither higher salt stress 80 mm or 120 mm showed significant variations with the application of ga3. germination percentage significantly increased 1.33% and 1.66% in control and 50 mm nacl, respectively in the secondary seeds of previously exogenous application of ga3 in salinity stress. however, results showed that the percentage of germination of secondary seed decrease collaterally with the increase of salt stresses throughout the treatments. in the present study, germination percentage increased in secondary seeds. these results revealed that secondary seeds from saline conditions with exogenous application of asa, si, and ga3 increased seed performances. usually, salt stresses reduce photosynthetic parameters, chlorophyll content and stomatal opening, and hinder the normal growth of plant, while affecting the proper seed development (neill et al., 2002; netondo et al., 2004). fig. 1. germination percentage of salt-stress induced secondary seeds from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. relative water content relative water content of seedlings of secondary seed showed insignificant variations. rwc of seedlings of secondary seeds previously treated in 100 mm nacl with different mitigating agents (asa, 2 mm), si, 200 µm) and ga3, 100 µm), while ga3 showed significant results in control and asa in 50 mm nacl, respectively (figure 2). the highest increase of rwc of secondary seedling was observed in previously treated 50 mm nacl by asa application under salt stressed. rwc is considered as an important parameter for evaluating plants for tolerance to salinity stress (boyer et al., 2008). in this study, salinity stress led to a significant decrease of rwc in wheat with increasing nacl concentration (figure 2). in the previous studies, the rwc of the plant decreased under salinity stress conditions in a diverse group of plants (polash et al., 2018; keyvan, 2010). decrease in rwc was due to loss of turgor that results in physiological drought for cell extension processes (shamsi and kobraee, 2013). however, when salt treated wheat plants were supplemented with asa, si and ga3, plant showed increased rwc which was due to the retention in water in their tissue (figure 2). the enhanced water content in plants due to exogenous application of protectants was also observed by other researchers (hasanuzzaman et al., 2013). performance of wheat seedlings under salt stress 119 fig. 2. relative water content of salt stress induced secondary seeds from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. growth parameter shoot and root length shoot length of seedlings from secondary seed significantly increased (4.0%, 7.4%, 9.5% and 10.6%, respectively) with previously exogenous application of ga3 under different salinity level (figure 3). shoot lengths were higher in lower or minimal salt stressed. the exogenous application of asa (2 mm), si (200 µm) and ga3 (100 µm) in previous experiment under different salt stress improved the shoot length of seedling derived from secondary seeds. in addition, shoot lengths were decreased respectively in previously increased doses of salt treated seeds. root length of seedlings from secondary seeds were significantly increased with previously exogenous application of si (200 µm) and ga3 (100 µm) under different salt stresses. the highest results (9.6%, 19%, 13% and 8.5% increase under 0, 50, 80 and 120 mm nacl) were found from the ga3 (100 µm) application under all the salt stresses (figure 4). results showed the similar type of reduction in root length as shoot length under salt stresses. salinity stress restricts plant growth due to osmotic stress and ionic toxicity (munns et al., 2006). under salt stress, root cells may lose water instead of absorbing it due to the hyperosmotic pressure of the soil solution. as a result physiological drought induced by salinity stress, resulting in decreased cell elongation, cell expansion, wilting and ultimately, decreased plant shoot and root growth (munns and tester, 2008). however, supplementation of osmoprotectants and synthetic plant growth regulator like asa, si and ga3 increased adaptation of wheat cultivars to salinity to some extent. this may be achieved through osmoregulation which in turn increased osmotic adjustment by increasing water flow and water status by using the organic solutes (islam and mehraj, 2014). 120 islam et al. fig. 3. shoot length of salt stress induced secondary seeds from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. fig. 4. root length of seedlings of secondary seeds induced different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. root-shoot ratio the seedlings of secondary seeds showed significant increase (10.8%) in root-shoot ratio. the highest root-shoot ratio was found in previously applied 120 mm nacl conditions. previously applied ga3 (100 µm) under 120 mm nacl treated secondary seeds showed effective result, while other doses of mitigating agents asa (2 mm), si (200 µm) and ga3 (100 µm)) were found ineffective under different salt stressed seeds (figure 5). the root-shoot ratio increased simultaneously with increased salt stresses in every previously treated seeds. performance of wheat seedlings under salt stress 121 fig. 5. root-shoot ratio of seedlings of secondary seeds derived from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. fresh and dry weight seedling-1 fresh weight of seedlings of secondary seed derived from different salt treated plant showed significant variations with different mitigating agents asa (2 mm), si (200 µm) and ga3 (100 µm). the highest increases in fw were observed by si (3.84%) in 80 mm nacl and ga3 (12.5%) under 120 mm nacl salt stressed secondary seedlings (figure 6). fresh weight in previously treated plants seeds were decreased with the increased salt stresses. dry weight of previously affected salt stressed seedlings of secondary seed showed significant variation and increased by si (200 µm) and ga3 (100 µm). exogenous application of salt stress mitigating agent si (200 µm) increased the seedling dw by 9.52% under 50 mm nacl and 80 mm nacl salt stressed conditions, while ga3 (100 µm) increased dw of salt stressed secondary seedlings by 12.5% under 120 mm salt stress (figure 7). dry weights in different treatments were also decreased with the increased salt stresses as like as fw of seedlings. fig. 6. fresh weight per seedling of salt stressed secondary seedlings from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. reduction of biomass, a significant disturbance in photosynthetic parameters along with reduced chlorophyll contents, reduction of stomatal conductance, photosynthesis rates, and inhibition of metabolic phenomena, and increased ros generation which can increase oxygen-induced cellular damage (neill et al., 2002). however, previously application of ga3, asa and si increased biomass of secondary seedlings. ga3 is plant hormones that are associated with various plant growth and development processes. ga3 plays a central role in tolerance to salinity stress by improving the activity 122 islam et al. of antioxidant enzymes and preventing lipid peroxidation, increased the accumulation of proline and potassium and increased the different physiological parameters, ultimately produced biomass (miceli et al., 2019; alsudays et al., 2020). on the other hand, application of asa helps to uptake nutrients (n, p and k), protects metabolic processes against h2o2 and other toxic derivatives of oxygen affected many enzyme activities, minimize the damage caused by oxidative processes through synergistic function with other antioxidants and stabilize membranes (farahat et al., 2013). furthermore, it was showed that si supplementation ameliorated the adverse effects of nacl on plants growth, biomass, and oxidative stress by increasing the content of proline and cytokinin (zhu et al., 2020). si supplement could induce salt tolerance in plants by improving photosynthesis, membrane integrity, and detoxification of toxic radicals and elevating its antioxidant capacity under salinity stress (robatjazi et al., 2020). fig. 7. dry weight per seedling of salt stressed secondary seedlings from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. vigor index salt stress mitigating agents (asa, 2 mm; si, 200 µm and ga3, 100 µm) previously treated salt stressed secondary seed showed significant increase in seedling vigor index. asa treated plants seeds increased 2.27, 3.54, 3.61, and 3.83%, respectively; si treated plants seeds increased 5.63, 11.17, 7.41 and 6.55%, respectively and ga3 treated plants seeds increased 8.49, 14.45, 12.26 and 10.43%, respectively in 0, 50, 80 and 120 mm nacl stresses (figure 8). the highest vigor indexes were found from the ga3 (100 µm) treated plants seeds in all the salt stresses. performance of wheat seedlings under salt stress 123 fig. 8. vigor index of previously salt treated seedlings of secondary seeds from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. survivability percentage there were no significant variations in survivability percentages with mitigating agents (asa, 2 mm; si, 200 µm and ga3, 100 µm) in different slat stressed secondary seeds except for 120 mm nacl treatment. survivability percentages increased 3.74% and 4.68% by asa (2 mm) and ga3 (100 µm), respectively (figure 9). however, survivability percentages decreased with increased salt stresses in salt stressed secondary seeds. fig. 9. survivability percentage of previously salt treated seeding of secondary seeds from different salinity level comprising salt stress mitigating agents. asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. mean (±sd) was calculated from three replicates for each treatment. values in a column with different letters are significantly different at p ≤ 0.05 applying lsd test. chlorophyll content in this experiment, chlorophyll (a, b and a+b) of salt stressed secondary seedlings did not show any significant variation with the application of salt stress mitigating agents (asa, 2 mm), si, 200 µm) and ga3,100 µm)) under previously four different salt stress conditions including control treatment (0, 50, 80 and 120 mm) (table 1). table 1. chlorophyll (a, b and a+b) of salt stressed secondary seeds of different salinity level comprising of salt stress mitigating agents. treatments chl a (nmol/g dw) chl b (nmol/g dw) chl (a+b) (nmol/g dw) 124 islam et al. control 0.67 ± 0.02 ab 0.38 ± 0.02 ab 1.06 ± 0.01 ab asa 0.66 ± 0.01 abc 0.39 ± 0.03 ab 1.05 ± 0.02 abc si 0.69 ± 0.02 a 0.41 ± 0.03 a 1.10 ± 0.02 ab ga3 0.67 ± 0.01 ab 0.38 ± 0.04 ab 1.05 ± 0.03 ab 50 mm nacl 0.68 ± 0.01 a 0.40 ± 0.02 ab 1.08 ± 0.01 ab 50 mm nacl + asa 0.67 ± 0.01 ab 0.40 ± 0.25 ab 1.07 ± 0.03 ab 50 mm nacl + si 0.70 ±0.02 a 0.41 ± 0.04 a 1.11 ± 0.02 a 50 mm nacl + ga3 0.68 ± 0.01 a 0.39 ± 0.04 ab 1.07 ± 0.04 ab 80 mm nacl 0.67 ± 0.05 ab 0.37 ± 0.01 bc 1.04 ± 0.05 abc 80 mm nacl + asa 0.66 ± 0.05 abc 0.37 ± 0.01 bc 1.03 ± 0.06 bc 80 mm nacl + si 0.69 ±0.05 a 0.40 ± 0.02 ab 1.08 ± 0.05 ab 80 mm nacl+ ga3 0.67 ± 0.05 ab 0.36 ± 0.03 bcd 1.03 ± 0.06 bc 120 mm nacl 0.60 ± 0.04 cd 0.33 ± 0.01 cd 0.93 ± 0.05 d 120 mm nacl + asa 0.58 ± 0.05 d 0.33 ± 0.01 cd 0.92 ± 0.07 d 120 mm nacl + si 0.61 ± 0.04 bcd 0.36 ± 0.01 bcd 0.97 ± 0.05 cd 120 mm nacl + ga3 0.60 ± 0.04 cd 0.32 ± 0.02 d 0.92 ± 0.07 d lsd(0.05) 0.029 0.020 0.037 cv (%) 5.57 6.70 4.38 asa, si and ga3 indicate 2 mm ascorbic acid, 200 µm sio2 and 100 µm gibberellic acid, respectively. means (±sd) were calculated from three replications (n = 3) for each treatment. values with different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. however, the application of salt stress mitigation agent si (200 µm) in showed simultaneous increase in chlorophyll (a, b and a+b) under different salt treatments in secondary seedlings. the highest increase in chlorophyll a (2.23, 2.20, 2.08 and 2.5% in 0, 50, 80 and 120 mm, respectively), chlorophyll b (7.74, 4.68, 7.68 and 9.02% in 0, 50, 80 and 120 mm, respectively) and chlorophyll a+b (4.18, 3.11, 4.10 and 4.76% in 0, 50, 80 and 120 mm, respectively) were found in salt stressed secondary seedlings from previously treated plants by si (table 1). in addition, the lowest chlorophyll a, b and a+b were found from the highest salt stress 120 mm). salinity stress often causes alteration in photosynthetic pigment biosynthesis (cuin et al., 2010). kiani-pouya and rasouli (2014) reported that the chlorophyll content decreased significantly under severe salinity stress in wheat. however, exogenous application of asa, si and ga3 in salt treated plant increased chl content (tahir et al., 2012). conclusion the application of salt stress mitigating agents like asa, si and ga3 all together improve the plant growth and development as well as enhance the secondary seed performances. in this study seeds and seedlings performances from the previously exogenous applied salt stress mitigating agents in wheat plant’s seeds showed significant variations in germination percentage, shoot length, root length, fresh and dry weight seedling-1 and vigor indexes. however, the performances of secondary seed and seedlings in this study elucidates that exogenous application of salt stress mitigating agents may significantly reduce the stress impacts in wheat plants under different salt stresses as well as in secondary seeds during their germination and seedling growth. in this study, secondary seeds from ga3 application in salt stressed plants significantly have increased the seed germination and seedling growth parameters, while silicon mostly improved the fresh weight and chlorophyll (a, b and a+b) and asa showed better relative water contents with other parameters in secondary seeds. preceding research hardly explain the secondary seeds performances, thus further research is necessary on this topic. the results of this study have evaluated the secondary seeds performances which plants treated by salt stress mitigating agents during salt stress conditions. acknowledgement performance of wheat seedlings under salt stress 125 the authors are thankful to dr. mirza hasanuzzaman, professor, department of agronomy, sher-ebangla agricultural university for providing necessary facilities and successful execution of laboratory work to conduct the study. references abdul-baki, a.a. and j.d. anderson. 1973. vigor determination in soybean seed by multiple criteria1. crop sci. 13(6): 630. al sahil, a. 2016. effect of gibberellic and salicylic acids pre-soaking on seed germination attributes of cucumber (cucumis sativus l.) under induced salt stress. cercetariagron. moldova. 49: 99–109. alam, m., k. nahar, m. hasanuzzaman and m. fujita. 2014. alleviation of osmotic stress in brassica napus, b. campestris, and b. juncea by ascorbic acid application. biol. plant. 58(4): 697-708. alonso-ramírez, a., d. rodríguez, d. reyes, a.j. jiménez, g. nicolás, m. lópez-climent, a. gómezcadenas and c. nicolás. 2009. evidence for a role of gibberellins in salicylic acid-modulated early plant responses to abiotic stress in arabidopsis seeds. plant physiol. 150(3): 1335-44. alsudays, i.m.a. and h.e.s.a. el sayed. 2020. influence of ascorbic acid, gibberellic acid and moringa oleifera extract for alleviating salinity stress by enhancing antioxidant enzymatic activity and some physiological studies on two tomato cultivars. j. appl. life sci. int. 23(12): 39-62. arnon, d.i. 1949. copper enzymes in isolated chloroplasts. polyphenol oxidase in beta vulgaris. plant physiol. 24(1): 1–15. barrs, h.d. and p.e. weatherley. 1962. a re-examination of the relative turgidity techniques for estimating water deficits in leaves. aust. j. biol. sci. 15: 413-428. boyer, j.s., r.a. james, r. munns, t.a. condon, and j.b. passioura. 2008. osmotic adjustment leads to anomalously low estimates of relative water content in wheat and barley. funct. plant biol. 35(11): 1172-1182. costat. 2008. costatstatistics software version 6.400. cohort software, 798 lighthouse ave. pmb 320, monterey, ca, 93940, usa. cuin, t.a., d. parsons and s. shabala. 2010. wheat cultivars can be screened for nacl salinity tolerance by measuring leaf chlorophyll content and shoot sap potassium. funct. plant biol. 37(7): 656-664. de tullio, m.c., r. liso and o. arrigoni. 2004. ascorbic acid oxidase: an enzyme in search of a role. plant biol. 48: 161-166. fao (food and agriculture organization). 2015. agristat. fao, rome. www.fao.org (accessed 27 jan. 2016). farahat, m.m., a.m. azza, h.m. mona and m.z. sahar. 2013. salt tolerance in grevillea robusta seedlings via foliar application of ascorbic acid. middle-east j. sci. res. 14(1): 09-15. gill, s.s. and n. tuteja. 2010. reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants. plant physiol. biochem. 48(12): 909–930. doi:10.1016/j.plaphy.2010.08.016. hasanuzzaman, m., k. nahar and m. fujita. 2013. plant response to salt stress and role of exogenous protectants to mitigate salt-induced damages. in: ecophysiology and responses of plants under salt stress. ahmed, p., m.m. azooz and m.n.v. prasad, (ed.). springer, new york. pp.25–87. hasanuzzaman, m., m.a. hossain and m. fujita. 2011. nitric oxide modulates antioxidant defense and the methylglyoxal detoxification system and reduces salinity-induced damage of wheat seedlings. plant biotechnol. rep. 5: 353-365. hasanuzzaman, m., m.a. hossain, j.a.t. da silva and m. fujita. 2012. plant responses and tolerance to abiotic oxidative stress: antioxidant defense is a key factor. in: crop stress and its management: perspectives and strategies. bandi, v., a.k. shanker, c. shanker and m. mandapaka, (ed.). springer, berlin. pp.261– 316. 126 islam et al. hassan, n.m., z.m. el-bastawisy, a.k. el-sayed, h.t. ebeed and m.m. nemat alla. 2015. roles of dehydrin genes in wheat tolerance to drought stress. j. adv. res. 6: 179-188. ibrahim, m.e.h., x. zhu, g. zhou and e.h. abidallhaa. 2016. effects of nitrogen on seedling growth of wheat varieties under salt stress. j. agric. sci. 8: 131. islam, s. and h. mehraj. 2014. growth and yield of wheat as influenced by ga3 concentrations. int. j. bus. soc. sci. res.2(1): 74-78. keyvan, s. 2010. the effects of drought stress on yield, relative water content, proline, soluble carbohydrates and chlorophyll of bread wheat cultivars. j. anim. plant sci. 8(3): 1051-1060. khandakar, a.l. 1980. a rational basis for testing jute seed quality. bangladesh j. jute fib. res. 5(1&2): 5157. kiani-pouya, a. and f. rasouli. 2014. the potential of leaf chlorophyll content to screen bread-wheat genotypes in saline condition. photosynthetica. 52(2): 288-300. machado, r.m.a. and r.p. serralheiro. 2017. soil salinity: effect on vegetable crop growth, management practices to prevent and mitigate soil stalinization. horticulturae. 3: 30. miceli, a., a. moncada, l. sabatino and f. vetrano. 2019. effect of gibberellic acid on growth, yield, and quality of leaf tomato and rocket grown in a floating system. agron. 382(9): 1-22. munns, r. and m. tester. 2008. mechanisms of salinity tolerance. annu. rev. plant biol. 59: 651-681. munns, r., r.a. james and a. lauchli. 2006. approaches to increasing the salt tolerance of wheat and other cereals. j. exp. bot. 57: 1025–1043. nahar, k., m. hasanuzzaman and m. fujita. 2016. roles of osmolytes in plant adaptation to drought and salinity. in: osmolytes and plants acclimation to changing environment: emerging omics technologies. iqbal, n., r. naza, and n.a. khan, (ed.). springer, new delli. pp.37-58. neill, s.j., r. desikan, a. clarke, r.d. hurst and j.t. hancock. 2002. hydrogen peroxide and nitric oxide as signaling molecules in plants. j. exp. bot. 53(372): 1237-1247. netondo, g.w., j.c. onyango and e. beck. 2004. sorghum and salinity: ii. gas exchange and chlorophyll fluorescence of sorghum under salt stress. crop sci. 44(3): 806-811. ozfidan-konakci, c., e. yildiztugay and m. kucukoduk. 2015. protective roles of exogenously applied gallic acid in oryza sativa subjected to salt and osmotic stresses: effects on the total antioxidant capacity. plant growth regul. 75: 219–234. polash, m.a.s., m.a. sakil, m. tahjib-ul-arif and m.a. hossain. 2018. effect of salinity on osmolytes and relative water content of selected rice genotypes. trop. plant res. 5(2): 227-232. rahman, a., k. nahar, m. hasanuzzaman and m. fujita. 2016a. calcium supplementation improves na+/k+ ratio, antioxidant defense and glyoxalase systems in salt-stressed rice seedlings. front. plant sci. 7: 609. rahman, a., m.s. hossain, j.a. mahmud, k. nahar, m. hasanuzzaman and m. fujita. 2016b. manganeseinduced salt stress tolerance in rice seedlings: regulation of ion homeostasis, antioxidant defense and glyoxalase systems. physiol. mol. biol. plants. 22(3): 291-306. reddy, p.s., g. jogeswar, g.k. rasineni, m. maheswari, a.r. reddy, r.k. varshney and p.v.k. kishor. 2015. proline over-accumulation alleviates salt stress and protects photosynthetic and antioxidant enzyme activities in transgenic sorghum. plant physiol. biochem. 94: 104–113. robatjazi, r., p. roshandel and s.d. hooshmand. 2020. benefits of silicon nutrition on growth, physiological and phytochemical attributes of basil upon salinity stress. int. j. hort. sci. technol. 7(1): 37-50. ryu, h. and y. yong-gu. 2015. plant hormones in salt stress tolerance. j. plant biol. 58(3): 147– 155. doi:10.1007/s12374-015-0103-z. shaddad, m.a.k., h.m. abd elsamad and d. mostafa. 2013. role of gibberellic acid (ga3) in improving salt stress tolerance of two wheat cultivars. int. j. plant physiol. biochem. 5(4): 50-57. performance of wheat seedlings under salt stress 127 shahbaz, m., a. abid, a. masood and e.a. waraich. 2017. foliar-applied trehalose modulates growth, mineral nutrition, photosynthetic ability, and oxidative defense system of rice (oryza sativa l.) under saline stress. j. plant nutr. 40: 584-599. shamsi, k. s. and kobraee. 2013. biochemical and physiological responses of three wheat cultivars (triticum aestivum l.) to salinity stress. annal. biol. res. 4(4): 180-185. srivastava, r.k, p. pandey, r. rajpoot, a. rani, a. gautam and r.s. dubey. 2015. exogenous application of calcium and silica alleviates cadmium toxicity by suppressing oxidative damage in rice. protoplasma. 252: 959−975. tabatabei, s.a. 2013. the effect of salicylic acid and gibberellin on enzyme activity and germination characteristics of wheat seeds under salinity stress conditions. intl. j. agri. crop sci. 6(5): 236240. tahir, m.a., t. aziz, m. farooq and g. sarwar. 2012. silicon-induced changes in growth, ionic composition, water relations, chlorophyll contents and membrane permeability in two salt-stressed wheat genotypes. arch. agron. soil sci. 58(3): 247-256. venkatesh, j. and s.w. park. 2014. role of l-ascorbate in alleviating abiotic stresses in crop plants. bot. studies. 55: 38. wang, s., p. liu, d. chen, l. yin, h. li and x. deng. 2015. silicon enhanced salt tolerance by improving the root water uptake and decreasing the ion toxicity in cucumber. front. plant sci. 6: 759. wassmann, r., s. jagadish, s. heuer, a. ismail, e. redona, r. serraj, r. singh, g. howell, h. pathak and k. sumfleth. 2009. climate change affecting rice production: the physiological and agronomic basis for possible adaptation strategies. adv. agron. 101: 59–122. wu, g.q. and s.m. wang. 2012. calcium regulates k+/na+ homeostasis in rice (oryza sativa l.) under saline conditions. plant soil environ. 58(3): 121–127. wutipraditkul, n., p. wongwean and t. buaboocha. 2015. alleviation of salt-induced oxidative stress in rice seedlings by proline and/or glycinebetaine. biol. plant. 59(3): 547–553. you, j. and z. chan. 2015. ros regulation during abiotic stress responses in crop plants. front. plant sci. 6: 1092. zeng. f., f. zhao, b. qiu, y. ouyang, f. wu and g. zhang. 2011. alleviation of chromium toxicity by silicon addition in rice plants. agric. sci china. 10(8): 1188–1196. zhu, y., x. jiang, j. zhang, y. he, x. zhu, x. zhou and y. liu. 2020. silicon confers cucumber resistance to salinity stress through regulation of proline and cytokinins. plant physiol. biochem. 156: 209220. zhu, y.x. and h.j. gong. 2014. beneficial effects of silicon on salt and drought tolerance in plants. agron. sustain. dev. 34: 455-472. bangladesh agron. j. 2021, 24(2): 91-97 intercropping of spinach with bottlegourd as a leafy vegetables under different planting methods m.s. islam1 , m.f. khatun2*, q. naher3, m.f. hossain3, m.s. hossain4 1sso, ofrd, bari, kishoreganj-2300; 2sso, pgrc, bari, gazipur-1701; 3sso, ofrd, bari, gazipur-1701; 4sso, srdi, regional laboratory, kishoreganj-2300 *corresponding email: mfkhatun79@gmail.com (received: 25 september 2021, accepted: 15 december 2021) keywords: intercropping, leafy vegetables, spinach, bottle gourd, land equivalent yield abstract intercropping is the option of growing more crops in the same piece of land for additional profit and to mitigate the losses or failure of the main crop. considering this view, an experiment was designed to observe the growth and yield performance of spinach as an intercrop with bottle gourd as leafy vegetable under various planting method to increase productivity and economic return. the study included four planting systems viz; broadcasting spinach with bottle gourd, line sowing spinach with bottle gourd, sole bottle gourd and sole spinach followed by rcb design with three dispersed replications. based on the growth and yield performance with economic return, intercropping performed better than sole cropping. the higher bottle gourd equivalent yield (15.67 to 28.36 %) was obtained in line sowing of spinach with bottle gourd than sole bottle gourd. the land equivalent ratio (ler) showed a positive influence on intercropping systems compare to monoculture. the maximum gross return (tk. 430000 ha-1), gross margin (tk. 325000 ha-1) and bcr (4.10) was obtained from line sowing of spinach with bottle gourd. this practice could be able for better return with the same input and using the same area of land with minimum risk. introduction in bangladesh, the majority of farmers are practicing monoculture rather than an intercropping system. however, intercropping use nutrients efficiently and gives greater yield stability over monoculture (seran and brintha, 2010). moreover, mixed or intercropping can ensure maximum land utilization of the available resources and compared with each sole crop to increase productivity (launay et al., 2009;mucheru-muna et al., 2010). in the past, bottle gourd was consumed as lau but recently the young leaves and twigs as shak are getting popularity due to its palatability and health benefits. at present, laushak production areas are covering 16156 acres of land with total production of 26812 metric tons (bbs, 2019). farmers can harvest twig at least 8-10 times within a season from a single plant. but nowadays, the price of 3-4 twigs of laushak remains expensive and varies tk. 15-20 in the local market. after 7-10 days of twig cutting, another 3 to 4 twigs comes out from each plant and grow up quickly due to epical dominance. on the other hand, spinach as a short duration vegetable it can quickly grow up in the line without causing yield hamper. in the early season, the price of spinach also expensive in market compare to other vegetables. therefore, farmers can get spinach within a short time as an additional cropand canearn extraearly income. hence, this study has been conducted to observe the growth and yield performance of spinach as an intercrop with bottle gourd. material and method mailto:mfkhatun79@gmail.com 92 islam et al. the experiment was conducted at mlt site hossainpur (aez -7, latitude 240 25´ n and longitude 90o 39´ e) under ofrd, bari, kishoreganj during the rabi season of 2015-16 and 2016-17 to evaluate the performance of intercropping spinach with bottle gourd as a leafy vegetable. four planting systems were maintained t1: broadcasting spinach with bottle gourd, t2: line sowing spinach with bottle gourd, t3: sole bottle gourd and t4: sole spinach. the completely randomized block design with three dispersed replications was laid out. seeds sowing was done on 5 october 2015 and 24 october 2016. bottle gourd was planted 50 and 25 cm of line to line and plant to plant distances, respectively where 15 and 10 cm for spinach. fertilizer doses: n75 p25k60 kg and 10 tons per hectare decomposed cowdung were used. full dose cowdung, tsp and 1/2 amount of mop were applied at final land preparation. one-third urea was applied at 21 das after seed sowing. the rest of urea and mop were applied at the time of each cutting of bottle gourd twig. irrigation and intercultural operations were done as and when necessary. foliar application of liquid fertilizer at 10 days interval was also done three times to enhance the vegetative growth. secure was also used 3 times to protect the gummosis disease on the same day’s interval. the insecticide confidor and desis were also used 2 times in the growing season to control red pumpkin beetle and aphid. fifteen-time twig of bottle gourd was harvested as a leafy vegetable from single plant whereas spinach was harvested on 18 november 2015 and lau shak started from 25 november 2015 in 2015-16 cropping season. in 2016-17, spinach was harvested on 30 november 2016 and lau shak on 5 january 2017. as an intercrop, the spinach yield was converted to equivalent laushak yield. data recorded on yield and yield attributing characters and analyzed the mean differences by (lsd) test (gomez and gomez, 1984). the laushak equivalent yield (t ha-1) was quantified by using the equation (1) mentioned by prasad and srivastava (1991). on the other hand, the land equivalent ratio was also calculated by equation (2) (mian, 2008). moreover, based on the prevailing market price of bottle gourd and spinach was considered to calculate the economic performance following the existing market price. bey (t ha -1)=bottle gourd yield (t ha -1)+ spinach yield (t ha -1) x spinach price (tk. kg -1 ) bottle gourd price (tk. kg -1 ) …(1) ler= yield of intercrop(bottle gourd) yield of sole crop (bottle gourd) + yield of intercrop (spinach) yield of sole crop (spinach) ………………………(2) table 1. nutrient status of cowdung (%) name of the manure ph om ca mg k total n p s b zn cowdung 7.2 8.5 1.74 0.53 0.56 0.57 0.8 0.2 0.012 0.14 the initial soil samples of the experimental field were collected and analyzed (table 2). the ph, oc and total nitrogen of the soil were highly acidic (5.51), low (0.91%) and low (0.06%), respectively, while available p, k, ca, mg, s, zn and b were over the critical value. table 2. chemical properties of initial soil sample in the study field soil depth ph oc (%) total n (%) p (mg kg-1) k ca mg s zn b (mg 100 g-1) mg kg-1 0-20 (cm) 5.51 0.91 0.06 20 0.19 3.8 1.6 10.5 2.13 0.61 critical level 7.0 0.12 2.0 0.5 10 0.60 0.20 the average maximum precipitation of 25.7 mm in october and the minimum rainfall 8.2 mm recorded in january. besides, the average maximum temperature was 31.96oc in the month of october and 12.95oc as minimum temperature in january. results and discussion yield and yield contributing characters of bottle gourd intercropping of spinach with bottlegourd as a leafy vegetables 93 the yield and yield contributing characters of bottle gourd as leafy vegetable were influenced significantly under different planting system with spinach except number of twigs per plant (table 4). the maximum average twig length (87.26 cm) was recorded from t3 treatment (sole bottle gourd) which was (78 cm) statistically similar to t2 treatment (line sowing spinach with bottle gourd) may be due to minimum interspecific competition as well as optimum light interception, nutrient and water uptake for growth that reflects on higher twig length. the lowest average twig length (71.85 cm) was found in t1 treatment. a similar trend was found in individual twig weight (g) and bottle gourd twig yield (t ha-1). the highest average individual twig weight was obtained (89.6 g) in t3 treatment (sole bottle gourd) and the lowest was obtained (155.8 g) from t1 treatment which was statically at par to t2 treatment. the maximum average bottle gourd twig yield (13.33 t ha-1) resulted in t3 treatment (sole bottle gourd) that was statically similar t2 treatment (12.06 t ha -1). the similar result was reported by bhuiyan et al. (1999); ofrd (2006) where intercropping provided the highest yield than sole maize. the minimum bottle gourd twig yield was found (11.40 t ha -1) in t1 treatment (broadcasting spinach with bottle gourd). table 4. performance of yield and yield contributing characters of bottle gourd as leafy vegetables at different planting system during 2015-16 and 2016-17 treatments twig length (cm) mean individual twig weight (g) mean bottle gourd twig yield (t ha-1) mean 2015-16 2016-17 2015-16 2016-17 2015-16 2018-17 t1 73.40 70.30 71.85 151.6 160 155.8 11.22 11.57 11.40 t2 76.00 80.00 78.00 162.0 173.3 167.7 11.89 12.23 12.06 t3 86.40 88.52 87.46 194.0 185.2 189.6 13.25 13.41 13.33 lsd (0.05) 10.6 9.22 10.63 12.12 0.78 1.42 cv (%) 5.86 6.12 17.12 11.55 6.57 4.89 lsd=least significant differences, ns=no significant, cv=coefficient of variance, ,t1: broadcasting, spinach with bottle gourd, t2: line sowing spinach with bottle gourd, t3: sole bottle gourd spinach yield as intercrop the average, yield data has been presented in table 5. the maximum spinach yield was recorded (4.44 t ha-1) from t4 treatment (sole spinach) which was statistically similar in t2 treatment (3.83 t ha-1) it might be less sharing of input. quayyum and maniruzzaman(1995) who reported that the single cropping practice having little or no sharing of input sun and air within the plants. on the contrary, the minimum spinach yield was obtained (3.29 t ha-1) in t1 treatment. bottle gourd equivalent yield the equivalent yield of bottle gourd was influenced by different cropping systems (table 5). the highest bottle gourd equivalent yield was found (17.2 t ha-1) in t2 treatment than the sole spinach and the sole bottle gourd due to adding intercrop yield. total productivity can increase significantly as compared to single cropping by making better use of water, nutrients and solar energy (yildirim and guvenc, 2005). alom et al. (2013) also reported the brinjal equivalent yields (bey) in all intercropping systems were found higher than sole brinjal indicating higher productivity of intercropping systems. similar results were also reported by suresha et al. (2007) in different chilli based intercropping systems. t1 treatment gave the second highest equivalent yield (15.5 t ha-1) which was statistically similar to t3 due to higher bottle gourd twig weight. on the other hand, the lowest bottle gourd equivalent yield was found in t4 treatment (4.44 t ha-1). by practicing this system yield increased over the sole bottle gourd 15.67 to 28.36% from the intercropping treatments. land equivalent ratio 94 islam et al. the maximum ler value was calculated from t2 treatment (1.80) followed by t1 treatment (1.60)(table 5) which was indicated the superiority of intercropping over both sole crop (t3 and t4). table 5. equivalent yield and percent yield (%) increased of bottle gourd and spinach during 2015-16 and 2016-17 (average) treatments spinach yield (t ha-1) spinach yield (t ha-1) bottle gourd twig yield (t ha-1) bottle gourd equivalent yield (t ha-1) ler 2015-16 2016-17 t1 3.09 3.48 3.29 11.4 15.5 1.60 t2 3.56 4.10 3.83 12.6 17.2 1.80 t3 13.4 13.4 1.00 t4 4.12 4.76 4.44 4.44 1.00 t1: broadcasting spinach with bottle gourd, t2: line sowing spinach with bottle gourd, t3: sole bottle gourd andt4: sole spinach ler: land equivalent ratio economic performance of spinach with bottle gourd as a leafy vegetable intercropping system spinach with bottle gourd economically profitable than sole cropping (table 6). the highest gross return (tk. 430000 ha-1), gross margin (tk. 105000 ha-1) as well as bcr (4.10) were recorded in t2 treatment. uddin et al., 2009 also reported that maize + spinach provided the highest yield with highest gross income followed by maize + lalshak and maize + potato, but sole crop maize had produced lowest yield with a least gross return. in the case of the intercropping system, the total variable cost was high due to cultivation cost was much higher under all intercropping systems than sole cropping because of extra labor cost for sowing, harvesting and intercultural activities for the two crops cultivation. table 6. equivalent yield and economic analysis ofspinach with bottle gourd intercropping at different planting system treatments bottle gourd equivalent yield (t ha-1) yield increased over sole bottle gourd (%) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 15.5 15.67 384500 102000 282500 3.77 t2 17.2 28.36 430000 105000 325000 4.10 t3 13.4 335000 98000 237000 3.42 t4 4.44 111000 80000 31000 1.40 t1: broadcasting spinach with bottle gourd, t2: line sowing spinach with bottle gourd,t3: sole bottle gourd and t4: sole spinach, tvc: total variable cost, bcr: benefit cost ratio, price: bottle gourd twig (lau shak) tk.25 kg-1 and spinach tk.30 kg-1 the intercropping system gave higher gross margin than the sole cropas reported by razzaque et al. (2007) &alom et al. (2008). in this study, the highest gross return (tk.111000 ha-1), gross margin (tk.8000 ha-1) from t4 treatment but bcr much lower (1.40) so, treatment t2 showed higher bcr (4.10) followed by t3 (3.42) due to higher gross return. conclusion vegetable cultivation under the intercropping system is more profitable and viable in terms of economically and agronomical aspects which able to increase the total production. the study revealed that the intercrop of spinach or any short duration vegetables especially line sowing with bottle gourd would be suitable and profitable for in bangladesh. farmers are interested to cultivate leafy vegetable with bottle gourd which would contribute some additional profit with minimum effort and costing, thereby met up the vegetable requirement and nutritional demand of the farm family. intercropping of spinach with bottlegourd as a leafy vegetables 95 acknowledgements the authors thank the owner of the experimental field for providing land and continuous support to conduct the research. the authors also express their gratitude to thescientific assistant who involves this study and acknowledge to the moa and bari, gazipur for ensuring financial support to carry out the research. references alom, m.s., n.k. paul and m.a. quayyum. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean (vigna radiata l.) in different planting methods. saarc j. agri. 6(2): 73–82. alom, m.s., b.l. nag, m.n. islam, f.ahmed and s.akther. 2013. performance of different crop species with pointed gourd (trichosanthes dioica roxb.) bangladesh j. agril. res. 38(3): 523-529. akhtar, s., m.s. zaman, n. sultana, m.a.h. khan, m.m. zaman, s. sultana and m.k. alam. 2015. intercropping of short duration vegetables with hybrid maize. int. j. appl. res. 1(2): 113-116. bbs (bangladesh bureau of statistics). 2019. agricultural statistical yearbook of bangladesh. statistics division, bangladesh bureau of statistics. ministry of planning, government of the people’s republic of bangladesh, dhaka. bhuiyan, m.k.a., m.m. haque, q.a.khaliq, j.a. begum and a.h.m.r. mawlla. 1999. productivity and economics of grain legumes intercropped with maize. bangladesh agron. j. 9 (1&2): 35-42. black, c.a. 1965. method of soil analysis part -i and ii. am. soc. agronomy inc. madison, wiscosin, usa. p.770. caballero r., e.l. goicoechea and p.j. hernaiz.1995. forage yield and quality common vetch and oat sown at varying seed ratios and seedling rates of common vetch. field crops res. 41: 135-140. farhad, i.s.m., m.m.u. chowdhury, s.k. bhowal, a.k. choudhury and a.s.m.m.r. khan. 2014. chilli-garlic intercropping system in costal saline area. app. sci. report. 6(2): 47-50. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research (2nd ed.). newyork: wiley. pp.188–206. hanlon, e.a. and g.v. johnson. 1984. bray/kurtz, mehlich ill, ab/d and ammonium acetate extraction of p, k, and mg in four oklahoma soils. commun. soil sci. plant anal.15: 277–294. islam, m.s., m.f. khatun, a.s.m.m.r. khan, s. istiaque and m.f. hossain. 2016. intercropping vegetables with maize in the haor area of kishoreganj. j. agril. sci. 1(2): 49-53. islam, m.r., m.a.k. main, n. ara and m.f. hossain. 2013. intercropping lentil and turmeric relayed with pointed gourd. bangladesh j. agric. environ. 9(1): 33-37. islam, m.n., m. akhteruzzaman, m.s. alom and m. salim. 2014.hybrid maize and sweet potato intercropping: a technology to increase productivity and profitability for poor hill farmers in bangladesh. saarc j. agri. 12(2): 101-111. jackson, m.l. 1962. soil chemical analysis. new york: prentice-hall inc. p.498. karim, z., s.m. rahman, m.i. ali and a.j.m.s. karim. 1988. soil bulk density: a manual for determination of soil physical parameters. dhaka, bangladesh: soils and irrigation division, barc. launay, m., n. brisson, s. satger, h. hauggaard-nielsen, g. corre-hellou, e. kasynova, r. ruske, e.s. jensen and m.j. gooding. 2009. exploring options for managing strategies for pea-barley intercropping using a modeling approach. eur. j. agron. 31: 85-98. mucheru-muna, m., p. pypers, d. mugendi and b. vanlauwe. 2010. a staggered maize-legume intercrop arrangement robustly increases crop yields and economic returns in the highlands of central kenya. field crops res. 115: 132-139. 96 islam et al. mian, m.a.k. 2008. performance of maize oriented cropping patterns under different nutrient management. ph. d. dissertation. dept. agron. bangladesh agril. univ., mymensingh. pp. 31-137. matusso, j.m.m., j.n. mugwe, and m. mucheru-muna. 2012. potential role of cereal-legume intercropping systems in integrated soil fertility management in smallholder farming systems of sub-saharan africa research application summary. third ruforum biennial meeting 24-28 september 2012, entebbe, uganda. okigbo, b.n. 1979. evaluation for plant interactions and productivity in complex mixtures as a basis for improved cropping systems design: in: proc. intl. workshop on intercropping 10-13 jan., hyderbad, india.pp.350-356. ofrd (on-farm research division).2006. bangladesh agricultural research institute, joydebpur, gazipur, intercropping maize with short duration vegetables crop. annual res. report. pp.291-297. prasad, k. and v.c. srivastava. 1991. pigeonpea (cajanus cajan) and soybean (glycine max) intercropping system under rainfed situation. indian j. agric. sci. 61(4): 243-246. quayyum, m.a. and a.f.m. maniruzzaman. 1995. effect of maize (zea mays l.) and rice (oryza sativa) with black gram (phaseolus mungo). indian j. agron. 40(1): 20-25. rodge, b.m. and s.s. yadlod. 2009. studies of intercropping in vegetables. intl. j. agril. sci. 5(2):357-358. razzaque, m.a., s. rafiquzzaman, m.m.m. bazzaz, a. ali and m.m.r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agril. res. 32(1): 37-43. seran, t.h. and i. brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135-145. saddam, a.a. 2009. effect of intercropping of zeamaize with potato solanum tuberosum, l. on potato growth and on the productivity and land equivalent ratio of potato and maize. j. agric. 4: 164-170. suresha, b.a., t.b. allolli, m.g. patil, b.k. desai and s.a hussain. 2007. yield and economics of chilli based intercropping system. karnataka j. agric. sci. 20 (4): 807-809. sperber, i. 1948. a direct turbidimetric method for determining eitheral sulfates in urine. j. bio. chem. 172: 441–444. uddin, m.j., m.a. quayyum and k.m. salahuddin. 2009. intercropping of hybrid maize with short duration vegetables at hill valleys of bandarban. bangladesh j. agric. res. 34(1): 51-57. van oort, p.a.j., f.gou, t.j. stomphand van der werf, w. 2020. effects of strip width on yields in relay-strip intercropping: a simulation study. european j.agron.112:125936. walkley, a. and i.a. black. 1934. an examination of degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. soil sci. 37: 29–37. yildirim, e. and i. guvenc. 2005. intercropping based on cauliflower: more productive, profitable and highly sustainable. european j. agro. 22: 11-18. economic performance of spinach with bottle gourd as a leafy vegetable table 6. equivalent yield and economic analysis ofspinach with bottle gourd intercropping at different planting system bangladesh agron. j. 2020, 23(2): 81-86 influence of organic manures on drought stress at different growth stages of wheat a.k.m.r. amin and m.a. baque department of agronomy, sher-e-bangla agricultural university corresponding e-mail: ruhulsau@yahoo.com (received: 30 september, 2020, accepted: 22 november, 2020) keywords: organic manure, drought stress, yield, wheat abstract a pot experiment was conducted in the net house of the agronomy department, sher-ebangla agricultural university, dhaka during the period from november, 2018 to march, 2019 to evaluate the suitable organic source to mitigate the drought stress impact on wheat. the experiment comprised two factors viz. factor a: three levels of organic manures, i) o0 = control (without organic manure), ii) o1 = cowdung (10 t/ha), iii) o2 = poultry litter (5 t/ha), and factor b: four levels of drought i) d0 = control (without drought), ii) d1 = crown root initiation stage (at 20-29 das), iii) d2 = booting stage (at 45-54 das), iv) d3 = anthesis stage (at 55-64 das). the experiment was laid out in a completely randomized design (factorial) with three replications. organic manure showed positive impact on yield and cowdung (o1) gave the highest grain yield (4.06 g plant -1 ). this may be attributed to the highest number of effective tillers plant -1 (3.21), spike length (9.53 cm), spikelet spike -1 (17.31), grains spikelet -1 (2.31) and 1000-grain weight (44.61 g) of wheat in this treatment. in respect of drought imposition treatments, grain yield was found higher in control treatment (without imposition of drought) which was statistically similar with drought imposition at booting stage treatment (d2). these two treatments also showed highest number of effective tillers plant -1 , spikelets spike -1 , grains spike -1 and 1000-grain weight. regarding the interaction of organic manure and drought, cowdung without drought imposition (o1d0) and cowdung with drought imposition at booting stage (o1d2) were highest yielder among the other interactions which was attributed to higher 1000-seed weight, number of effective tillers plant -1 , spikelets spike -1 and grains spike -1 . results revealed that application of organic manure could reduce the impact of drought on wheat irrespective of growth stages. however, application of cowdung (10 t ha -1 ) was found more effective to combat drought impact at booting stage of wheat compared to other growth stages. introduction wheat (triticum aestivum l) is the most important cereal crop in the world and it is one of the main sources of carbohydrate and also contains a considerable amount of protein, minerals and vitamins. it has significant role in human nutrition. drought stress is one of the major abiotic stresses, which adversely affects crop growth and yield. drought is the most common environmental stress affecting about 32% of the 99 million hectares under wheat cultivation in developing countries and at least 60 million hectares under wheat cultivation in developed countries (rajaram, 2000). drought stress reduces plant growth by affecting various physiological and biochemical processes, such as transpiration, translocation, ion uptake and nutrient metabolism (farooq et al., 2008). understanding of plant responses to drought stress is of great importance and a fundamental part for making the crops tolerant to stress conditions (zhao et al., 2008). some studies suggest that drought stress influences the thermal tolerance of photosynthesis (havaux, 1992). mirzaei et al. (2011) reported that drought stress induced at all growth stages reducing grain yield and yield components. drought stress at stages of mailto:ruhulsau@yahoo.com 82 amin and baque stem elongation, flowering and grain filling stages induced 32, 32 and 35% reduce in grain yield, respectively. sarwar (2005) also found that grain yield and yield components of wheat significantly increased with the application of different organic materials resulting in the compost to be the most superior one. in addition, yassen et al. (2006) was found that the irrigation at 60% water holding capacity and applying mineral nitrogen 60 kg/fed, with presence of the chicken manure as an organic fertilizer produced the highest wheat yield through two growth seasons. as such, this experiment was designed to determine the effect of water stress at different growth stages of wheat and to combat water stress through application of organic manure. materials and methods the pot experiment was conducted at the net house of the department of agronomy, sher-e-bangla agricultural university (sau), dhaka-1207, during the period of november 2018 to march 2019. the experimental field was located at 23 0 41’ n latitude and 90 o 22’ e longitude at a height of 8.6 m above the sea level. the soil of the experimental site was clay loam belonging to the “madhupur tract” under aez 28. the experiment comprised two factors viz. factor a: organic manure (o)-3, i) o0 = control (recommended dose of chemical fertilizer/ rdcf + without organic fertilizer ), ii) o1 = rdcf + cowdung, iii) o2 = rdcf + poultry litter, factor b: comprising drought by removing irrigation4 i) d0 = control (without drought), ii) d1 = crown root initiation stage (at 19-20 das), iii) d2 = booting stage (at 45-54 das), iv) d3 = anthesis stage (at 55-64 das). the experiment was laid out in a completely randomized design (factorial) with three replications. a total of 36 earthen pots measuring 22 cm diameter and 18 cm height were collected from the local market. each pot was fill-up with 20 kg of soil. urea, tsp, mop, gypsum, zinc oxide and boric acid were used at the rate of 200, 72, 66, 110, 4 and 5 kg ha -1 (2.00, 0.72, 0.66, 1.10, 0.04 and 0.05 g pot -1 ), respectively mixed with the soil before fill-up the pot except urea. urea was applied in three equal splits at pot filling up, 21 das and 55 das. cowdung and poultry litter were applied in the pots @ 10 and 5 t ha -1 , respectively as per treatment. seeds of wheat variety bari gom28 were collected from wheat research center, bangladesh agriculture research institute (bari) campus, joydebpur, gazipur. before sowing, seeds were treated with provex 200ec @ 2.5 g powder for kg -1 seed. ten seeds were sown in each pot on 23 rd november 2018. after sowing, the seeds were covered with soil and lightly pressed by hand. five plants were kept for assessment in each pot after 14 das. different intercultural operations were done to ensure normal growth of the crop except irrigation. irrigation was applied as per need of treatment of the experiment where irrigation was not applied during drought imposition period(s) treatments. the crop was harvested at different dates on the basis of physiological maturity. the crop was harvested on 11 march, 2019. data on different crop characters, yield attributes and yield were collected from the harvested five plants from each pot. threshing, cleaning and drying of grains were done separately for each treatment. properly dried grain and straw were weighed and converted into g plant -1 basis. the collected data of each pot were statistically analyzed to obtain the level of significance using the computer-based software statistics10. mean difference among the treatments were tested with duncan’s multiple range test (dmrt) test at 5 % level of significance. results and discussion significant difference existed among different organic manures with respect to yield and yield contributing characters (table 1 and table 2). the yield advantages of 0.45 g and 0.75 g plant -1 for o1 (cowdung) applied pot over o2 (poultry litter) and o0 (no organic manure) applied pot was found possibly aided by higher tillers plant -1 (3.21), spike length (9.53cm), spikelets spike -1 (17.31), grains spike -1 (2.31), weight of 1000-grains (44.61 g), straw yield (4.44 g plant -1 ), biological yield (8.50 g plant -1 ) and harvest index (47.26%) in the o2 (cowdung) applied treatment. the result agrees with the findings of ibrahim et al. (2008) and hammad et al. (2011) that organic fertilizer increased wheat yield https://www.researchgate.net/profile/hafiz_hammad?_sg=fkqgoy4kb07hvrr6lm72m-jt7kfl9k7nar0uwaaorlryfsi3xhh_q_rrc-jcst7qcvhhjdg.g9fje5swm_xby25cxphaxcmx68dasscsifzsnw3cumrxx2fcf1qhhkjlta8fdelgfvvdqva0lmv9sqfyiebiqw influence of organic manures on wheat 83 over control. according to uyanoz et al. (2006) yield attributes of wheat improve with organic manure which corroborates with the present findings. table 1. effect of organic manures on plant height and yield attributes of wheat organic manure plant height (cm) effective tillers plant-1 (no.) spike length (cm) spikelet spike-1 (no.) grains spikelet-1 (no.) grains spike-1 (no.) weight of 1000 grains (g) o0 69.105 b 2.02 c 8.34 b 16.18 b 1.94 b 31.01 c 39.69 b o1 76.779 a 3.21 a 9.53 a 17.31 a 2.31 a 37.16 a 44.61 a o2 70.171 b 2.65 b 8.50 b 16.52 b 1.92 b 32.71 b 40.41 b se 2.42 0.14 0.19 0.33 0.06 0.70 0.99 cv (%) 8.23 13.17 5.21 4.90 7.60 5.09 5.86 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: o0= control (only rdcf + no organic manure), o1= rdcf + cowdung, o2 = rdcf + poultry litter table 2. effect of organic manure on yields and harvest index of wheat organic manure grain yield plant-1 (g) straw yield plant1 (g) biological yield plant-1 (g) harvest index (%) o0 3.31 c 3.73 c 7.04 c 46.66 o1 4.06 a 4.44 a 8.50 a 47.26 o2 3.56 b 4.05 b 7.61 b 46.51 se 0.0819 0.776 0.1526 ns cv (%) 5.51 4.67 4.85 3.75 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: o0= control (only rdcf+ no organic manure), o1= rdcf + cowdung, o2 = rdcf + poultry litter the result reveled that among the drought imposed treatments, the control plants d0 (without drought) and d2 (drought imposition at booting stage, 45-54 das) showed highest and statistically similar grain yield, effective tillers hill -1 , spikelet spike -1 , grains spike -1 , weight of 1000 gains and harvest index (table 3 and table 4). d0 (without drought) treatment was out yielded by producing 28.99% and 65.78% higher yield over d1 (drought imposition at crown root initiation stage) and d3 (drought imposition at anthesis stage), respectively. on the other hand, d2 (drought imposition at booting stage) treatment was out yielded by producing 23.96% and 59.32% higher yield over d1 (drought imposition at crown root initiation stage) and d3 (drought imposition at anthesis stage), respectively. the treatment d0 (without drought) also produced highest level of tillers plant -1 , spikelets spike -1 , grains spike -1 , straw yield, biological yield and harvest index than drought imposition plants. however, among the drought imposition treatments d2 (drought at booting stage) gave highest yield and yield attributes than other drought imposition treatments. the present result was supported by the findings of akram (2011) that drought imposition at different growth stages caused severe reduction in yield and yield components of wheat. similar result was also observed by alghabari and isham, (2018) that drought stress affected barley yield through impaired grain development and grain filling duration. 84 amin and baque table 3. effect of drought stress on plant height and yield attributes of wheat drought stage plant height (cm) effective tillers (no.) spike length (cm) spikelet spike-1 (no.) grains spikelet-1 (no.) grains spike-1 (no.) weight of 1000 grain (g) d0 76.02 a 2.93 a 9.82 a 17.94 a 2.29 a 36.70 a 44.82 a d1 69.82 bc 2.47 bc 8.40 c 16.00 b 1.95 b 32.16 b 40.33 b d2 74.73 ab 2.75 ab 9.11 b 17.62 a 2.16 a 35.26 a 43.10 a d3 67.50 c 2.36 c 7.83 d 15.10 c 1.83 b 30.40 c 38.05 b se 2.7952 0.1630 0.2161 0.3852 0.0737 0.8072 1.14.76 cv (%) 8.23 13.17 5.21 4.90 7.60 5.09 5.86 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: d0 = control (no stress), d1= crown root initiation stage (20-19 das), d2 = booting stage (45-54 das) and d3= anthesis stage (55-64 das) table 4. effect of drought stress on yields and harvest index of wheat drought stage grain yield plant-1 (g) straw yield plant-1 (g) biological yield plant-1 (g) harvest index (%) d0 4.36 a 4.70 a 9.06 a 48.10 a d1 3.38 b 3.89 c 7.27 c 46.29 b d2 4.19 a 4.43b 8.62 b 48.27 a d3 2.63 c 3.26d 5.90 d 44.59 b se 0.0946 0.0896 0.1762 0.8268 cv (%) 5.51 4.67 4.85 3.75 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: d0 = control (no stress), d1= crown root initiation stage (20-19 das), d2 = booting stage (45-54 das) and d3= anthesis stage (55-64 das) interaction of organic manure and drought stress treatment showed significant variation in all the studied parameters in this experiment (table 5 and table 6). the interaction of o1d0 (cowdung × without drought treatment) and o1d2 (cowdung × drought at booting stage) performed best in respect of grain yield (4.72 and 4.55 g plant -1 , respectively) which may be attributed to highest effective tillers plant -1 , spike length, spikelet spike 1 , grains spikelet 1 and weight of 1000-grain in these interactions. table 5. interaction effects of organic manure and drought stress on plant height and yield contributing characters of wheat interaction (organic manu. × drou.) plant height (cm) effective tillers plant-1 (no.) spike length (cm) spike let spike-1 (no.) grains spikelet-1 (no.) grains spike-1 (no.) weight of 1000 grains (g) o0d0 70.76 a-d 2.21 e 9.44 bc 17.18 bc 2.15 bc 34.09 bc 45.14 a-c o0d1 68.40 b-d 1.88 e 7.87 f-h 15.61 d-f 1.82 ef 29.56 ef 37.76 fg o0d2 71.53 a-d 2.10 e 8.77 c-e 17.61 ab 1.87 de 32.22 c-e 41.91 b-e o0d3 65.73 cd 1.87 e 7.27 h 14.29 f 1.93 c-e 28.19 f 33.97 g o1d0 79.83 a 3.48 a 10.79 a 18.91 a 2.51 a 40.02 a 46.99 a o1d1 75.47 a-c 3.12 ab 9.08 b-d 16.56 b-d 2.13 b-d 35.83 b 43.28 a-d o1d2 78.72 a-d 3.32 ab 9.72 b 17.72 ab 2.63 a 39.02 a 45.93 ab influence of organic manures on wheat 85 o1d3 73.10 a-d 2.95 a-c 8.54 d-f 16.03 c-e 1.99 b-e 33.78 b-d 42.25 b-d o2d0 77.47 ab 3.10 ab 9.22 b-d 17.73 ab 2.20 b 36.00 b 42.32 b-d o2d1 65.60 cd 2.40 c-e 8.24 e-g 15.83 c-e 1.91 c-e 31.08 d-f 39.95 d-f o2d2 73.95 a-c 2.83 b-d 8.84 c-e 17.53 ab 1.98 b-e 34.53 bc 41.46 c-f o2d3 63.67 d 2.26 de 7.69 gh 14.97 ef 1.57 f 29.22 f 37.92 e-g se 4.84 0.28 0.37 0.66 0.12 1.39 1.98 cv (%) 8.23 13.17 5.21 4.90 7.60 5.09 5.86 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: o0= control (only rdcf+ no organic manure), o1= rdcf + cowdung, o2 = rdcf + poultry, d0 = control (no stress), d1= crown root initiation stage (20-19 das), d2 = booting stage (45-54 das) and d3= anthesis stage (55-64 das) table 6. interaction effects of organic manures and drought stress on yields and harvest index of wheat interaction (organic manure × drought) grain yield plant -1 (g) straw yield plant -1 (g) biological yield plant -1 (g) harvest index (%) o0d0 4.07 cd 4.48 c 8.55 c 47.52 a-d o0d1 2.78 fg 3.40 ef 6.18 ef 45.00 d-f o0d2 3.91 d 3.86 d 7.77 d 50.32 a o0d3 2.47 g 3.16 f 5.63 f 43.80 f o1d0 4.72 a 4.96 a 9.69 a 48.75 ab o1d1 4.00 cd 4.41 c 8.41 47.47 a-d o1d2 4.55 ab 4.87 ab 9.42 ab 47.10 b-e o1d3 2.96 f 3.51 e 6.47 e 45.72 c-f o2d0 4.30 bc 4.65 a-c 8.95 bc 48.02 a-c o2d1 3.35 e 3.87 d 7.22 d 46.39 b-f o2d2 4.10 cd 4.56 bc 8.66 c 47.38 a-d o2d3 2.47 g 3.12 f 5.59 f 44.24 ef se+ 0.16 0.15 0.30 1.43 cv (%) 5.51 4.67 4.85 3.75 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: o0= control (only rdcf+ no organic manure), o1= rdcf + cowdung, o2 = rdcf + poultry, d0 = control (no stress), d1= crown root initiation stage (20-19 das), d2 = booting stage (45-54 das) and d3= anthesis stage (55-64 das) conclusion it may be concluded from the result that, application of cowdung (10 t ha -1 ) seems promising to overcome yield loss due to drought stress at booting stage of wheat. acknowledgement: ministry of science and technology. references akram, m. 2011. growth and yield components of wheat under water stress of different growth stages. bangladesh j. agril. res. 36(3): 455-468. alghabari, f. and m.z. ishan. 2018. effect of drought stress on growth, grain filling duration, yield and quality attributes of barley (houdium vulgare l.). bangladesh j. bot. 47(3): 421-428. bbs (bangladesh bureau of statistics). 2018. 45 years agriculture statistics of major crops. bangladesh bureau of statistics (bbs) statistics and informatics division (sid), ministry of planning. p.194. 86 amin and baque farooq, m., a. wahid, n. kobayashi, d. fujita and s.m.a. basra. 2009. plant drought stress: effects, mechanisms and management. agron. sust. dev. 29: 185-210. hammad, h.m., a. khaliq, a. ahmad and k. laghar. 2011. influence of different organic manures on wheat productivity. intl. j. agric. biol. 13(1): 137-140. havaux, m. 1992. stress tolerance of photo system ii in vivo: antagonistic effects of water, heat, and photo inhibition stresses. plant physiol. 100: 424-432. ibrahim, m., a. hussain, m. iqbal and e. valeem. 2008. response of wheat growth and yield to various levels of compost and organic manure. pakistan j. bot. 40(5): 2135-2141. mirzaei, a., r. naseri, and r. soleimani. 2011. response of different growth stages of wheat to moisture tension in a semiarid land. world appl. sc. j. 12(1): 83-89. rajaram, s. 2000. international wheat breeding: past and present achievements and future directions. in warren e kronstand honorary symposium, 18 feb 1999, oregon state university extension service, special report p.1017. sarwar, g. 2005. use of compost for crop production in pakistan. ökologie und umweltsicherung. 26/2005. universität kassel. uyanoz, r., u. cetin and e. karaarslan. 2006. effect of organic materials on yields and nutrient accumulation of wheat. j. plant nut. 29(5): 959-974. yassen, a.a., m. abd el-hady and s.m. zaghloul. 2006. replacement part of mineral n fertilizer by organic ones and its effect on wheat plant under water regime conditions. world j. agric. sci. 2: 421-428. zhao, c.x., l.y. guo, c.a. jaleel, h.b. shao and h.b. yang. 2008. prospects for dissecting plant-adaptive molecular mechanisms to improve wheat cultivars in drought environments. comp. rend. biol. 331: 579–586. https://www.researchgate.net/profile/hafiz_hammad?_sg=fkqgoy4kb07hvrr6lm72m-jt7kfl9k7nar0uwaaorlryfsi3xhh_q_rrc-jcst7qcvhhjdg.g9fje5swm_xby25cxphaxcmx68dasscsifzsnw3cumrxx2fcf1qhhkjlta8fdelgfvvdqva0lmv9sqfyiebiqw bangladesh agron. j. 2022, 25(1): 57-65 salt stress tolerance and germination performance of mungbean genotypes under salt stress m.s. kobir, m.o. ali, j. hossain, m.s. alam, m. rahman, k.u. ahammad, p. hajong, and s. paul bangladesh agricultural research institute, bangladesh corresponding email: shahriar1302027@gmail.com (received: 25 april 2022, accepted: 19 may 2022) keywords: germination, mungbean, seedling, nacl stress abstract sea level rising, as a result of global warming, is a major threat to crop production; because inclusion of saline water in crop land limits the crop production. so, an experiment was undertaken to evaluate some mungbean genotypes under different levels of salt stresses in germination stage. the experiment was conducted at regional agricultural research station, jashore during rabi 2020-2021. the seeds of seven mungbean genotypes viz. bari mung-6, bari mung-8, bmxki-112004-3, bmxki112009-21, mmat-v07, bmmp-201524 and bmmp-201506 were collected from different sources. this experiment was conducted following factorial completely randomized design (crd) with two replications. the experimental factors were i) mungbean genotypes (seven) and ii) salt stress (three levels: 0, 4 and 8 dsm-1). the results showed that mungbean var. bari mung-6 at 0 dsm-1 and 4 dsm-1 showed highest value in case of germination index (9), germination percentage (100%), co-efficient of germination (40), vigor index (1950) and lowest value in case of mean germination time (2.5). bari mung-8 at 0 ds m-1 showed the inverse results. genotype bmxki-11200921, mmat-v07 and bmmp-201524 at 4 dsm-1 and in some extent in 8 dsm-1 showed highest value in case of germination stress tolerance index, plant height stress index, root length stress index, shoot fresh weight stress index, root fresh weight stress index, shoot dry weight stress index and in root dry weight stress index. the lowest values in these parameters were found in bari mung-8 at 8 dsm-1 salt stress. bari mung-6, mmat v07, bmxki-112009-21 and bmmp-201524 genotypes were found to be more tolerant to salt stress than rest of the genotypes in germination stage. introduction mungbean is an important pulse crop in bangladesh which is grown for its various nutritional benefits and as for green manuring purposes. its grain is used for human consumption as it contains 19.5%28.5% protein. bangladesh has produced about 37,000 m tons mungbean from 109,000 acres of land in 2019-2020 (bbs, 2021). for crop production, biodiversity, food and nutritional security, soil salinity is a serious threat now-adays. in 1973, salinity affected area in bangladesh was 8330 square km whereas in 2009 it increases in around 10560 square km (srdi, 2010). more than thirty-five million people are living in coastal region of bangladesh in 19 districts which covers about 32% of the whole country huq and rabbani (2011). the growth of most salt sensitive crop plant is inhibited due to excessive na+ and cl-ion. the effect of nacl salt solution concentration on plant growth has been studied in different pulse crop species. at 50mm of nacl, reduction of dry mass production in glycine max, phaseolus vulgaris and brassica juncea in increased salt concentration was found by taffouo et al. (2004) and syeed et al. (2011). in 58 kobir et al. vigna unguiculata and mucuna poggei effect of nacl was observed in 100mm of nacl. combination of osmotic and specific ion effects of na+ and cl-can reduce the dry mass in increased salinity level munns (2002). salt tolerance of a plant can be defined as the plants can complete its life cycle in certain concentration of salt substrates. on the basis of morphological, physiological and biochemical indices different scientific techniques like conventional breeding, selection and transgenics can be used to mitigate the salinity stress in plants. selection of salt tolerant genotypes in the early stage can be a very reliable strategy as this strategy is less time consuming, less laborious and less expensive dasgan et al. (2002). understanding the physiological or biochemical processes that is more sensitive to salt stress that can be used as effective selection criterion is also important, ashraf and harris (2004). therefore, the objective of this study was to evaluate the influence of salt stress on germination and seedling growth of seven mungbean genotypes with a view to a better understanding of the mechanisms and capability of salt tolerance in these genotypes. materials and methods the experiment was conducted at regional agricultural research station, jashore during rabi 202021. seven selected genotypes of mungbean viz., bari mung-6, bari mung-8, bmxki-112004-3, bmxki-112009-21, mmat-v07, bmmp-201524, and bmmp-201506 was tested and evaluated in vitro condition in petridishes at 0, 4 and 8 ds m-1 nacl salt solution. a two factorial experiment was set in following factorial completely randomized design (crd) with two replications. the experimental factors were i) mungbean genotypes (seven) and ii) salt stress (three levels: 0, 4 and 8 ds m-1). the seven genotypes were randomly assigned to seven petri dishes (9 cm diameter) of which each petri dish contained 10 seeds of each genotype following two replications. three salt treatments i.e., 0 (control), 4 and 8dsm–1were obtained by dissolving laboratory grade nacl in the solution until the treatment level reached to the desired ec. an ec meter was used to check the desired ec regularly. the control i.e., 0 dsm–1 was maintained using distilled water only. the seeds were soaked in water and imbibed for 24 hours and then placed in petri dishes containing filter paper to allow them for germination. in control, 4 ml of distilled water was added to the petri dish. filter papers were moistened with 4 ml of respective salt solutions to develop the respective level of salt treatments (4 ds m-1 and 8 dsm–1). the mungbean seeds were allowed to germinate at around 25°c room temperature and kept them for eight days for observation. the number of germinated seeds (2 mm radicle length) was counted every day. the final count was done on day eight and germination percentage (gp) was calculated using the following formulae stated by almudaris (1998). germination percentage (%) = total no. of seed germinated in final day total no. of seed taken × 100 co-efficient of germination (cg) was calculated using the following formula copeland (1976): 𝐶𝑜 − 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡𝑜𝑓𝑔𝑒𝑟𝑚𝑖𝑛𝑎𝑡𝑖𝑜𝑛(%) = 𝐴1 + 𝐴2 + ⋯ . 𝐴𝑥 𝐴1𝑇1 + 𝐴2𝑇2 + ⋯ 𝐴𝑥𝑇𝑥 × 100 where, cg = coefficient of germination (%), a = number of seeds germinated, t = time corresponding to a, x = number of days to final count. germination index was calculated as the product of number of days after sowing and number of germinated seeds divided by the total number of seeds sown li (2008). germination index (gi) = dini/ s where, di = number of days after sowing seeds under a particular treatment, ni = the number of germinated seeds and s = the total number of seeds sown for the experiment. performance of mungbean genotypes under salt stress 59 the mean germination time (mgt) was calculated using the daily counts, according to the following equation described by moradi et al. (2008): mgt = σ nd / σ n where, n is the number of newly germinated seeds at day d; d = days from the beginning of the germination test; n = number of all germinated seeds (final germination). the vigor of the seedlings was calculated according to the following formula stated by abdul-baki and anderson (1973): vigor index= {mean of root length + mean of shoot length} × seed germination (%) plumule length (pl) was measured from shoot base to the tip of the longest leaf and radicle length (rl) was measured from root base to the root tip. seedling fresh weight was recorded immediately after the harvest at day nine. root length stress tolerance index (rlsi), plant height stress tolerance index (phsi), shoot fresh weight stress tolerance index (sfsi), root fresh weight stress tolerance index (rfsi), shoot dry weight stress tolerance index (sdsi) and root dry weight stress tolerance index (rdsi) were calculated using the following formula described by ashraf and harris (2004): pi = nd1 (1.00) + nd2 (0.75) + nd3 (0.50) + nd4 (0.25) where, nd1, nd2, nd3 and nd4 = number of seeds germinated on the 2nd, 4th, 6th and 8th day, respectively. gsti = (pi of stressed seeds / pi of control seeds) x 100 phsi = (plant height of stressed plants / plant height of control plants) x 100 rlsi = (radicle length of stressed plants / radicle length of control plants) x 100 sfsi = (shoot fresh weight of stressed plants / shoot fresh weight of control plants) x 100 rfsi = (root fresh weight of stressed plants / root fresh weight of control plants) x 100 sdsi = (shoot dry weight of stressed plants / shoot dry weight of control plants) x 100 rdsi = (root dry weight of stressed plants / root dry weight of control plants) x 100 data of different parameters were recorded from five seedlings of each unit petri dish and analyzed statistically by statistical software statistix-10 and the mean separation was done by least significance difference test at 5% level of probability. results and discussion co-efficient of germination (cg) showed significant variation among the genotypes and salt treatments (figure 1). results revealed that cg decreased with the increase of salt concentration for all the genotypes except bari mung-6 and bmxki-112009-21. the highest cg was found by the genotype bari mung-6 in 4 dsm-1 salt solutions which is followed by genotype bmmp-201524 in 0.0 dsm-1 salt solutions and the lowest was found in bari mung-8 in 8 dsm-1 salt solutions (figure 1). 60 kobir et al. fig. 1. effect of different levels of salinity on selected mungbean genotypes in respect of co-efficient of germination. germination index (gi) showed significant differences for the genotypes and salt solutions (figure 2). results showed that in some genotypes gi increased in 4 dsm-1salt concentration compared to control but in 8 dsm-1 gi again decreased compared to control and 4 dsm-1 concentrations. the highest gi was found by bari mung-6 in control dishes and the lowest by the genotype bari mung-8 in 4 dsm-1 and 8 dsm-1 nacl salt solution (figure 2). similar results were also found by almodares et al. (2007) and khan and weber (2008). they reported that increasing of salinity level decreases the germination index, but in some cases certain level of salinity can enhance the germination capability of some genotypes which was accordance with the present findings. fig. 2. effect of different levels of salinity on selected mungbean genotypes in respect of germination index. germination percentage (gp) showed significant variation for genotypes and different salt concentrations (figure 3). in case of genotype bari mung-6, bari mung-8, and bmxki-112004-3 gp decreased with the increase of salt concentration but in case of genotype bmxki-112009-21, 0 5 10 15 20 25 30 35 40 45 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -8 b a r i m u n g -8 b a r i m u n g -8 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 m m a t -v 0 7 m m a t -v 0 7 m m a t -v 0 7 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 c o -e ff ic ie n t o f g e rm in a ti o n genotypes× salt sol. (ds m-1) lsd-13.48, p≤0.05 0 1 2 3 4 5 6 7 8 9 10 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -8 b a r i m u n g -8 b a r i m u n g -8 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 m m a t -v 0 7 m m a t -v 0 7 m m a t -v 0 7 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 g e rm in a ti o n i n d e x genotypes× salt sol. (ds m-1) (lsd-2.30, p≤0.05) performance of mungbean genotypes under salt stress 61 mmat-v07, bmmp-201524 and bmmp-201506 gp increased in 4 dsm-1 salt concentrations compared to control and 8 dsm-1 concentrations (figure 3). in controlled condition and in 8 dsm-1 salt concentrations the highest gp was found in bari mung-6 and the lowest in bari mung-8 (figure 3). in 4 dsm-1 concentrations highest gp was found in bari mung-6 and in bmmp-201506 and the lowest by bari mung-8 (figure 3). these findings indicated that there were genetically differences in different cultivars in respect to salt stress. lauchli and grattan (2007) stated that germination rates may vary with the species and genotypes in different salt stress conditions. the reduction of germination percentage might be due to alteration of enzymes and hormones that exists in the seeds khan and rezvi (1994). this might be also happened due to lower osmotic potential of germination media which leads to reduction of imbibition’s of water by planting materials khan and weber (2008). fig. 3. effect of different levels of salinity on selected mungbean genotypes in respect of germination percentage. mean germination time (mgt) showed significant variation for genotypes and salt concentrations (figure 4). mgt was increased with the increase of salinity for all the genotypes except bari mung-6 and bari mung-8. in these two genotypes mgt decreased in 4 dsm-1 salt concentration but mgt again increased in 8 dsm-1salt concentrations (figure 4). the longest mgt was found by bari mung8 in control dishes and in 8 dsm-1salt concentration there were no germinated seeds at all and the lowest mgt was observed by bari mung-6 in 4 dsm-1salt concentrations (figure 4). hapsari and trustinah (2018) also indicated that the increasing of salinity level could reduce the speed of germination. these results were also accordance with trustinah et al. (2016) and sehrawat et al. (2014). the speed of germination or mgt is more important than the germination rate as mgt indicate the growing strength of seed vigor by sadjad et al. (1999) and sari et al. (2013). 0 20 40 60 80 100 120 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -8 b a r i m u n g -8 b a r i m u n g -8 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 m m a t -v 0 7 m m a t -v 0 7 m m a t -v 0 7 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 g e rm in a ti o n p e rc e n ta g e genotypes×salt sol. (ds m-1) (lsd-27.44, p≤0.05) 62 kobir et al. fig. 4. effect of different levels of salinity on selected mungbean genotypes in respect of mean germination time. vigor index (vi) showed significant variations for genotypes and salt concentrations (figure 5). results revealed that vi decreased with the increase of salinity for all the genotypes. the highest vi was observed by bari mung-6 in 0 dsm-1 salt solutions and the lowest was found by bari mung-8 in 8 dsm-1 salt solutions (figure 5). similar trend was also reported by hapsari and trustinah (2018) and sehrawat et al. (2014). this might be happened as salt stress may negatively affect morphophysiological, biochemical and biometrics characters of mungbean sunil et al. (2012). fig. 5. effect of different levels of salinity on selected mungbean genotypes in respect of vigor index. germination stress tolerance index (gsti) showed significant variations for genotypes and nacl salt concentrations (table 1). the results showed that gsti decreased with the increase of salinity for all the genotypes except mmat-v07. the maximum gsti was found by bmxki-112004-3 in 4 dsm-1 which was followed by genotype mmat-v07 in 8 dsm-1 and bari mung-6 in 4 dsm-1 (table 1). the lowest gsti was observed by bari mung-8 in both 4 and 8 dsm-1. 0 1 2 3 4 5 6 7 8 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -8 b a r i m u n g -8 b a r i m u n g -8 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 m m a t -v 0 7 m m a t -v 0 7 m m a t -v 0 7 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 m e a n g e rm in a ti o n t im e ( d a y s) genotypes×salt sol. (ds m-1) (lsd-3.44, p≤0.05) 0 500 1000 1500 2000 2500 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -6 b a r i m u n g -8 b a r i m u n g -8 b a r i m u n g -8 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 4 -3 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 b m x k i1 1 2 0 0 9 -2 1 m m a t -v 0 7 m m a t -v 0 7 m m a t -v 0 7 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 2 4 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 b m m p -2 0 1 5 0 6 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 v ig o r in d e x genotypes×salt sol (ds m-1) lsd-540.80, p≤0.05 performance of mungbean genotypes under salt stress 63 plant height stress index (phsi) showed significant variations for genotypes and nacl salt concentrations (table 1). the results revealed that increase in salt concentration leads to decrease in phsi. the highest phsi was found by bmxki-112009-21 in 4 dsm-1salt concentrations and the lowest phsi by bari mung-8 in 8 dsm-1 concentrations. root length stress index (rlsi) showed significant variations for genotypes and nacl salt concentrations (table 1). the results revealed that increase in salt concentration leads to decrease in rlsi except genotype bmmp-201524. the maximum rlsi was found by bmxki-112009-21 in 4 dsm-1 salt concentrations followed by bmmp-201524 in 8 dsm-1 and the lowest rlsi by bari mung8 in 8 dsm-1 concentrations. root dry weight stress index (rdsi) showed significant variations for genotypes and nacl salt concentrations (table 1). all the genotypes exhibit minimal rdsi in both the salt concentrations except bmxki-112009-21 in 4 dsm-1. root fresh weight stress index (rdsi) showed significant variations for genotypes and nacl salt concentrations (table 1). the highest rfsi was found by genotype bmmp-201506 in 4 dsm-1 concentrations and the lowest rfsi by bari mung-8 and bmmp-201524 in both the salt concentrations and in bmxki-112004-3, bmxki-112009-21, bmmp-201506 when salt concentration was 8 dsm-1. shoot dry weight stress index showed non-significant variations for genotypes and nacl salt concentrations (table 1). shoot fresh weight stress index (sfsi) showed significant variations for genotypes and nacl salt concentrations (table 1). the results revealed that increase in salt concentration leads to decrease in sfsi for all the genotypes. the highest sfsi was found by bmmp-201524 in 4 dsm-1 salt concentrations followed by mmat-v07 in 4 dsm-1 salt stress and the lowest sfsi by bari mung-8 in 8 dsm-1 concentrations. table 1. salt tolerance stress indices as influenced by genotypes and salt stresses genotypes salt sol. (ds m-1) gsti phsi rlsi rdsi rfsi sdsi sfsi bari mung-6 4 115.00 52.90 49.76 0.0 51.31 50.00 66.69 bari mung-6 8 38.21 23.36 39.19 0.0 32.14 50.00 58.48 bari mung-8 4 0.00 20.00 17.44 0.0 0.00 0.00 25.00 bari mung-8 8 0.00 0.00 0.00 0.0 0.00 0.00 0.00 bmxki-112004-3 4 126.00 59.76 44.22 0.0 49.99 50.00 87.8 bmxki-112004-3 8 65.07 20.80 43.46 0.0 0.00 60.00 68.29 bmxki-112009-21 4 78.57 80.13 71.84 50 77.50 65.91 93.36 bmxki-112009-21 8 23.81 26.09 40.26 0.0 0.00 72.72 83.06 mmat-v07 4 97.14 43.26 64.50 0.0 66.66 83.62 96.44 mmat-v07 8 125.00 36.96 48.07 0.0 68.13 83.33 84.04 bmmp-201524 4 70.83 69.04 49.09 0.0 0.00 62.50 97.00 bmmp-201524 8 28.20 21.09 69.53 0.0 0.00 62.50 73.43 bmmp-201506 4 102.57 50.35 39.68 0.0 100.00 62.50 93.05 bmmp-201506 8 43.59 23.30 28.54 0.0 0.00 62.50 91.46 lsd(0.05) 75.9 36.11 67.08 47.93 43.58 ns 40.82 gsti= germination stress tolerance index, phsi= plant height stress index, rlsi= root length stress index, sfsi= shoot fresh weight stress index, rfsi=root fresh weight stress index, sdsi=shoot dry weight stress index, rdsi=root dry weight stress index, lsd= least significance differences in 5% level of probability salt stresses significantly reduce the seedling shoot and root height and biomass as well. this might be happened for the reduction of the plant ability to uptake water as osmotic deficit or for inclusion of toxic ions in the transpiration streams by munns (1993, 2005). several studies also reported significant reduction in seed germination and seedling growth in different crops and a large genotypic variation in response to salt stresses by farooq et al. (2015) and parihar et al. (2015). in case of 4 dsm-1 salt stress in some genotypes several physiological indices showed their highest positive result in present study. 64 kobir et al. hapsari and trustinah (2018) also corroborates the same results. they reported that some tested genotypes showed better normal seedling dry weight compared to control. dutta and bera (2014) also reported the same results as root fresh weight and dry eight were increased under salinity. conclusion the research work revealed significant differences among the mungbean genotypes in various salinity levels in germination and seedling stages. the germination percentage, germination index, coefficient of germination, vigor index and different salt tolerant indices were decreased with the increase of salinity level and the mean germination time increased with the increase of salinity. in some genotypes salt stress tolerance indices were increased in 4dsm-1 after that it decreased in the onset of increasing salinity level. mungbean var. bari mung-6, genotypes, mmatv07, bmxki-112009-21 and bmmp-201524 were found to be more tolerant to salt stress than other genotypes. this variability of genotypes can be used later for breeding program and further study will be needed for assessing whether these genotypes are performing the same in their growth and development phases under nacl salt stresses. references abdul-baki, a. and j.d. anderson. 1973. vigor determination of soybean seed by multiple criteria. crop sci. 3: 360– 633. almodares, a., m.r. hadi and b. dosti. 2007. effects of salt stress on germination percentage and seedling growth in sweet sorghum cultivars. j. biol. sci. 7: 1492–1495. almudaris, m.a. 1998. notes on various parameters recording the speed of seed germination. der tropenlandwirt. 99: 147-154. ashraf, m. and j.c. harris. 2004. potential biochemical indicators of salinity tolerance in plants. plant sci. 166: 3–16. https://doi.org/10.1016/j.plantsci.2003.10.024. bbs (bangladesh bureau of statistics). 2021. statistical yearbook of bangladesh. bureau of statistics, statistics division, ministry of planning, gov. of the people’s republic of bangladesh. dasgan, h.y., h. aktas, k. abak, and i. cakmar. 2002. determination of screening techniques to salinity tolerance in tomatoes and investigation and investigation of genotypes response. pl. sci. 163: 695– 703. https://doi.org/10.1016/s0168-9452(02)00091-2. dutta, p. and a.k. bera. 2014. effect of nacl salinity on seed germination and seeling growth of mungbean cultivars. agricultural research communicationcentre. legume res. 37(2): 161-164. farooq, m., m. hussain, a. wakeel and k.h.m. siddique. 2015. salt stress in maize: effects, resistance mechanisms and management – a review. agron. sust. dev. 35: 461–481. https://doi.org/10.1007/s13593-015-0287-0. hapsari, r.t. and trustinah. 2018. salinity tolerance of mungbean genotypes at seedling stage. biosaintifika. 10(2): 409-416. haque, m.a., d.e. jharna, m.f. hoque, m.n. uddin and m.a. saleque. 2008. soil solution electrical conductivity and basic cations composition in the rhizosphere of lowland rice in coastal soils. bangladesh j. agric. res. 33: 243–250. huq, s. and g. rabbani. 2011. climate change and bangladesh: policy and institutional development to reduce vulnerability. j. bangladesh stud. 13: 1–10. khan, m.a. and d.j. weber. 2008. ecophysiology of high salinity tolerant plants. 1st ed. springer, amsterdam. khan, m.a. and y. rizvi. 1994. effect of salinity, temperature and growth regulators on the germination and early seedling growth of atriplex griffithii var. stocksii. can. j. bot. 72: 475–479. https://doi.org/10.1139/b94-063. https://doi.org/10.1016/j.plantsci.2003.10.024 https://doi.org/10.1016/s0168-9452(02)00091-2 https://doi.org/10.1007/s13593-015-0287-0 https://doi.org/10.1139/b94-063 performance of mungbean genotypes under salt stress 65 li, y. 2008. effect of salt stress on seed germination and seedling growth of three salinity plants. pakistan j. bio. sci. 11: 1268–1272. https://doi.org/10.3923/pjbs.2008.1268.1272. moradi, d.p., f.s. zadeh and m. janmohammadi. 2008. influence of priming technique on seed germination behavior of maize inbreed lines (zea mays l.). j. agri. biol. sci. 3: 22-25. munns, m. 2002. comparative physiology of salt and water stress. plant cell env. 25: 230-250. munns, r. 1993. physiological processes limiting plant growth in saline soils: some dogmas and hypotheses. plant cell environ. 16: 1524. https://doi.org/10.1111/j.1365-3040.1993.tb00840.x. munns, r. 2005. genes and salt tolerance: bringing them together. new phytologist, 167: 645–663. https://doi.org/10.1111/j.1469-8137.2005.01487.x. parihar, p., s. singh, r. singh, v.p. singh and s.m. prasad. 2015. effect of salinity stress on plants and its tolerance strategies: a review. env. sci. pollu. res. inst. 22: 4056–75. https://doi.org/10.1007/s11356-014-3739-1. sadjad, s., e. murniati and s. ilyas. 1999. parameter pegujian vigor benihdari komparatifke simulatif. jakarta: grasindo: p.21. sari, m., e. widajati and p.r. asih. 2013. seed coating sebagai pengganti fungsi polong pada penyimpanan benih kacang tanah. jur. agr. indo. 41(3): 215-220. sehrawat, n., m. yadav, k.v. bhat, r.k. sairam and p.k. jaiwal. 2014. evaluation of mungbean genotypes for salt tolerance at early seedling growth stage. biocatalysis agri. biotech. 3(4): 108–113. srdi (soil resources development institute). 2010. saline soils of bangladesh. srdi, ministry of agriculture, dhaka, bangladesh. sunil, k.b., m. prakash, n. sathiya and j. gokulakrishnan. 2012. breeding for salinity tolerance in mungbean. in: 2nd international conference on asia agriculture and animal (icaaa 2012). apcbee procedia. 4: 30–35. syeed, s., n.a. anjum, r. nazar, n. iqbal, a. masood and n.a. khan. 2011. salicylic acid-mediated changes in photosynthesis, nutrients content and antioxidant metabolism in two mustard (brassica juncea l.) cultivars differing in salt tolerance. acta physiol. plant. 33: 877–886. taffouo, v.d., m. kenne, t.r. fokam, w.o. fotsop, t. fonkou, z. vondo and a. amougou. 2004. salt stress variation response in five leguminous plants, agron. afr. 16: 33 44. trustinah, r., r. iswanto and t. hapsari. 2016. toleransigalur f3 kacanghijauterhadapcekamansalinitas. pp.489-497. pros. sem. hasil penelitian tanaman aneka kacang dan umbi 2015. balitkabi, malang. https://doi.org/10.3923/pjbs.2008.1268.1272 https://doi.org/10.1111/j.1469-8137.2005.01487.x https://doi.org/10.1007/s11356-014-3739-1 bangladesh agron. j. 2023, 26(1): 9-17 effect of leaf clipping on growth and yield of blackgram (vigna mungo l.) a. sultana1, m.f. karim1, m.h. mahmud2*, s.c. sarker1 and m.d. hossain3 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2project implementation unit-barc, nata-phase-ii project, barc, dhaka-1215, bangladesh 3bangladesh wheat and maize research institute, regional station, jamalpur, bangladesh *corresponding author, email: h.mahmud193@gmail.com (received: 18 april 2023, accepted: 11 september 2023) keywords: pulse crop, source-sink relationship, leaf clipping, blackgram, seed yield abstract an experiment was conducted at sher-e-bangla agricultural university farm, dhaka to investigate the effect of variety and leaf clipping on the growth and yield of blackgram (vigna mungo l.) from march to june-2019. the experiment was laid out in a split-plot design with three replications. the treatments were blackgram variety (3); v1: bari mash-1, v2: bari mash-2 and v3: bari mash-3, and leaf clipping (4); c0: no leaf clipping (control), c1: clipping of 1st basal leaf, c2: clipping of 2nd basal leaves and c3: clipping of total apical leaves having no inflorescence. growth, yield and yield contributing characteristics were compared under different treatments. results indicated that variety and leaf clipping significantly affected most of the growth and yield contributing characteristics of blackgram. in the case of variety, mthe aximum value of the yield and yield contributing characteristics such as pod−1 length (8.99 cm), pods plant−1 (14.00), number of seeds pod−1 (9.78), 1000 seeds weight (48.58 g), and seed yield (1381.70 kg ha−1), were observed in var. bari mash-3. in the case of leaf clipping, maximum pod length (8.44 cm), pods plant−1 (15.18), seeds pod (9.32), 1000seeds weight (48.33 g), seed yield (1306.7 kg ha−1), was recorded in clipping of 1st basal leaf treatment. the blackgram var. bari mash-3 and clipping of 1st basal leaf was found superior in producing maximum pod length (9.32 cm), number of pods plant−1 (16.87), number of seeds pod−1 (10.80), 1000seeds weight (51.67 g), and seed yield (1456.70 kg ha−1). so, var. bari mash3 and clipping of 1st basal leaf may improve the growth and yield of blackgram. introduction pulses constitute an integral part of the human diet and are a potential source of protein for the millions of people of bangladesh. the per capita pulse consumption in bangladesh is only 14.3 g day−−1, much lower than the who recommendation of 45 g day−1 and the indian council of medical research recommendation of 60 g day−1 (afzal et al., 1999; hies, 2010). among the pulses, blackgram is very much popular in bangladesh and ranks 3rd in terms of consumption and total area in which different varieties of this crop are cultivated (bbs, 2021). bangladesh agricultural research institute (bari) developed several high-yielding varieties such as bari mash1, bari mash-2, bari mash-3, and bari mash-4 (bari, 2019). but farmers generally grow the local varieties, which affects the seed yield. cutting leaves from the plant is known as leaf clipping for better growth and development. photosynthetic active radiation is the major factor regulating photosynthesis and other physiological processes in plants. the dry matter production and yield depends on it to a greater extent. shading at both 50 and 75% of the full sunlight had significant negative effect on leaf area index (16 35%), total dry matter production (11 18%), grain yield (19 32%) of pulses over full sunlight (monoj et al., 2019). defoliation or leaf damage can decreases assimilate availability during grain filling, seed and biological yield (echarte et al., 2006). 10 sultana et al. defoliation up to a certain limit may be useful to overcome this problem of excessive vegetative growth. rao and ghildiyal (1985) stated that the remaining leaves of defoliated plant had higher net photosynthetic rate (pn) than intact plant improving yield. in bangladesh, few studies have been conducted to determine the effect of variety and leaf clipping on the growth and yield of blackgram. considering the above facts, the study was undertaken to find out the suitable variety and optimum level of leaf clipping on blackgram seed production. materials and methods the experiment was conducted in the agronomy field of sher-e-bangla agricultural university (sau). the experimental site is geographically situated at 23°77ʹ n latitude and 90°33ʹ e longitude and the agro-ecological zone (aez) of “the modhupur tract”, aez-28. the treatments were blackgram variety (3): v1=bari mash-1 v2=bari mash-2 v3=bari mash-3 and leaf clipping (5): c0=no leaf clipping (control), c1=clipping of 1st basal leaf, c 2=clipping of 2nd basal leaf and c3=clipping of total apical leaves having no inflorescence. the experiment was laid out in a split-plot design having 3 replications. blackgram varieties are assigned in the main plot, and leaf clipping treatment is in subplot. fertilizers were applied in the doses of 45, 90, 40, 55, and 10 kg ha−1 for urea, tsp, mop, gypsum, and boric acid, respectively. seeds were sown at the rate of 35 kg ha−1 in the furrow 30cm apart rows at about 2-3 cm depth and treated with bavistin before sowing the seeds to control the seed-borne diseases. leaf clipping was done at 30 das according to treatment variables. harvesting was done once when 90% of the pods became brown to black in color. harvest index was calculated on dry basis with the help of following formula. harvest index (hi%) = seed yield biological yield × 100 the collected data were compiled and analyzed statistically using comuter package program statistix 10 data analysis software and the mean differences were adjusted by least significant difference (lsd) test at a 5% level of probability (gomez and gomez, 1984). results and discussion plant height variety, leaf clipping and treatment combination has showed significant variation on plant height of blackgram at different days after sowing (das) (table 1). the maximum plant height (11.88, 28.35, 47.75, and 53.75 cm at 15, 30, 45 das and harvest, respectively) was observed from var. bari mash-3 t, which was statistically similar to var. bari mash-2 at 30 das (26.99 cm) and at harvest (51.67 cm) respectively. whereas the minimum plant height was observed from bari mash-1. the probable reason for this may be the varietal potentiality of the plant. the present study was similar to the findings of siddikee et al. (2018). at 15 das maximum plant height (11.50 cm) was observed in clipping of 1st basal leaf treatment, at 30 das maximum plant height (27.80 cm) was observed in no leaf clipping treatment which was statistically similar to clipping of 2nd basal leaves and clipping of 1st basal leaf treatment, and at 45 das and harvest, respectively the maximum plant height (48.24 cm and 55.20 cm) was observed in clipping of 1st basal leaf treatment. whereas the minimum plant height at 15 days (10.96 cm) was observed in clipping of 2nd basal leaves treatment which was statistically similar with clipping of total apical leaves having no inflorescence and no leaf clipping, and at 30, 45 das, and at harvest, respectively, the minimum plant height (25.51, 41.24, and 47.22 cm, respectively) was observed in clipping of total apical leaves having no inflorescence treatment. removal of leaves in certain levels may influence growth if the old or bacterial or pest infested leaves or sunburned leaves were effect of leaf clipping on growth and yield of blackgram 11 removed. the maximum plant height (12.19 cm and 29.32 cm) at 15 das and 30 das was observed in bari mash-3 with no leaf clipping and (53.07 cm and 58.23 cm) at 45 das and at harvest was observed in bari mash-3 with clipping of 1st basal leaf treatment combination. whereas the minimum (10.07 cm) at 15 das was observed in bari mash-2 with no leaf clipping. at 30, 45 das, and harvest, the minimum plant height (24.03, 38.63, and 45.20 cm, respectively) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence. table 1. effect of variety, leaf clipping and combination of treatment on the plant height and branch no. plant−1 of blackgram at different das plant height (cm) branch no plant−1 15 das 30 das 45 das at harvest 30 das 45 das at harvest variety v1 10.61c 25.83b 40.96c 48.19b 0.43c 3.27c 4.15c v2 10.91b 26.99a 44.58b 51.67a 0.57b 4.67b 5.68b v3 11.88a 28.34a 47.75a 53.75a 0.85a 6.28a 6.88a lsd (0.05) 0.52 1.55 2.11 2.34 0.05 0.18 0.35 leaf clipping c0 11.06b 27.80a 44.77b 51.92b 0.53c 4.53b 5.33b c1 11.50a 27.46a 48.24a 55.20a 0.91a 4.91a 5.91a c2 10.96b 27.47a 43.48b 50.47b 0.64b 4.87a 5.60b c3 11.01b 25.51b 41.24c 47.22c 0.38d 4.64b 5.24c lsd (0.05) 0.40 1.21 1.67 1.83 0.04 0.14 0.29 combination of treatment v1c0 10.93 cd 26.60 cd 40.00 ef 45.97 fg 0.47 ef 3.33 ef 4.13 e v1c1 10.73 de 26.11 c-e 43.70 cd 52.53 cd 0.53 e 3.53 e 4.33 e v1c2 10.36 de 26.60 cd 41.50 d-f 49.07 ef 0.40 fg 3.27 f 4.27 e v1c3 10.41 de 24.02 e 38.63 f 45.20g 0.33 g 2.93 g 3.87 e v2c0 10.07 e 27.49 a-d 45.90 bc 53.60 bc 0.67 d 4.73 cd 5.67 cd v2c1 12.05 a 27.11 b-d 47.97 b 54.83 bc 0.80 c 4.53 d 6.13 c v2c2 10.49 de 27.73 a-d 42.93 d 50.00 de 0.40 fg 4.87 c 5.73 c v2c3 11.03 b-d 25.67 de 41.53 de 48.23 e-g 0.40 fg 4.53 d 5.20 d v3c0 12.19 a 29.32 a 48.40 b 56.20 ab 0.47 ef 5.53 b 6.80 ab v3c1 11.73 ab 29.15 ab 53.0 7 a 58.23 a 1.40 a 6.67 a 7.27 a v3c2 12.03 a 28.09 a-c 46.00 bc 52.33 cd 1.13 b 6.47 a 6.80 ab v3c3 11.59 a-c 26.83 cd 43.55 cd 48.23e-g 0.40 fg 6.47 a 6.67 b lsd (0.05) 0.70 2.10 2.89 3.17 0.07 0.25 0.51 cv (%) 3.67 4.53 3.79 3.61 6.62 3.05 5.28 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. v1: bari mash-1, v2: bari mash-2, and v3: bari mash-3, and c0: no leaf clipping (control), c1: clipping of 1st basal leaf, c2: clipping of 2nd basal leaves and c3: clipping of total apical leaves having no inflorescence branches plant−1 variety, leaf clipping and treatment combination has showed significant variation on the branches plant−1 of blackgram (table 1). the maximum number of branches plant−1 (0.85, 6.28 and 6.88) at 30, 45 das, and at harvest, respectively) was observed in barimash-3 treatment. whereas numerically, the minimum number of branches plant−1 (at 30, 45 das, and at harvest, 12 sultana et al. respectively) was observed from bari mash-1. probably the varietal performance was responsible for the variation in branches plant−1 of blackgram. sunil et al. (2020) was also found similar results which supported the finding. the maximum number of branches plant−1 (0.91, 4.91, and 5.91 at 30, 45 das, and at harvest, respectively) was observed in clipping of 1st basal leaf treatment, which was statistically similar to clipping of 2nd basal leaves treatment at 45 das. whereas the minimum number of branches plant−1 (0.38) at 30 das was observed in clipping of total apical leaves having no inflorescence treatment, at 45 das, the minimum number of branches plant−1 (4.53) was observed in no leaf clipping, which was statistically similar with clipping of total apical leaves having no inflorescence and, at harvest, respectively, the minimum (5.24) was observed in clipping of total apical leaves having no inflorescence treatment, which was statistically similar with no leaf clipping (5.53) treatment during harvest. this could be that these lower leaves, only use photo assimilate for their maintenance apart from losing carbon for respiration. their removal has certainly helped to get more assimilate on the other parts and thereby enhance plant growth and development, but clipping of total apical leaves having no inflorescence caused injury damages to the plant. as a result, energy was being lost to makeup the injury and plant growth became detritions as a result the number of branches became pore in this part. ahmed (2017) was also found similar results. the maximum number of branches plant−1 (1.40, 6.67, and 7.27 at 30, 45 das, and at harvest, respectively) was observed in bari mash-3 with clipping of 1st basal leaf treatment combination. whereas numerically, the minimum number of branches plant−1 (0.33, 2.93, and 3.87 at 30, 45 das, and at harvest, respectively) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence treatment combination. above ground dry weight plant−1 the above-ground dry matter weight plant−1 of blackgram was not significantly influenced blackgram variety except for leaf clipping and treatment interaction (table 2). the maximum above-ground dry-weight plant−1 (1.59 g) was observed from no leaf clipping treatment at 15 das, which was statistically similar to clipping of 1st basal leaf treatment (1.57 g), at 30 das, numerically the maximum above-ground dry weight plant−1 (4.78 g) was observed form clipping of 1st basal leaf treatment which was statistically similar with no leaf clipping. at 45 das and harvest, respectively, the maximum above-ground dry-weight plant−1 (6.48 and 8.73 g) was observed in no leaf clipping treatment, which was statistically similar to all other treatments except clipping of total apical leaves having no inflorescence treatment at 45 das. whereas the minimum above-ground dry weight plant−1 (1.51 g) was observed from clipping of 2nd basal leaves at 15, 30, 45 das, and at harvest respectively, the minimum above-ground dry-weight plant−1 (4.61, 6.19, and 7.22 g) was observed form clipping of total apical leaves having no inflorescence, which was statistically similar with clipping of 2nd basal leaves at 30 das and at harvest respectively. sultana et al. (2013) was also found similar results. the maximum above-ground dry weight plant−1 (1.67, 5.63, 8.03, and 10.13 g at 15 das, 30 das, 45 das, and at harvest, respectively) was observed in bari mash-3 with no leaf clipping treatment combination, whereas the minimum above-ground dry weight plant−1 (1.47 g) was observed in bari mash-2 with clipping of total apical leaves having no inflorescence at 15 das, at 30 das (4.07 g) was observed in bari mash2 with clipping of 2nd basal leaves, at 45 das (4.80) was observed in bari mash-1 with clipping of 1st basal leaf and at harvest (5.94 g) was observed in bari mash-1 with clipping of 2nd basal leaves treatment combination. pod length plant−1 variety, leaf clipping and treatment combination has showed significant variation on pod length of blackgram (table 2). the maximum pod length of blackgram (8.99 cm) was observed in bari mash-3. in contrast, the minimum pod length plant−1 of blackgram (7.67 cm) was observed in bari mash-1 which was statistically similar with bari mash-2. the probable reason for this effect of leaf clipping on growth and yield of blackgram 13 may be the genetically potential of the variety that has helped in increasing pod length of blackgram variety. sunil et al. (2020) and siddikee et al. (2018) found similar result. the maximum pod length of blackgram (8.44 cm) was observed in clipping of 1st basal leaf treatment which was statistically similar with no leaf clipping and the minimum (7.95 cm) in clipping of total apical leaves having no inflorescence treatment which was statistically similar with clipping of 2nd basal leaves. leaf removal, may, therefore, influence yield and yield contributing characters through photosynthate production and its distribution into plant parts depending on the magnitude of clipping of leaves. (biswas et al., 2005). the maximum pod length of blackgram (9.32 cm) was observed in bari mash-3 with clipping of 1st basal leaf, whereas the minimum pod length plant−1 (7.42 cm) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence treatment combinations. number of pods plant−−1 variety, leaf clipping and treatment combination has showed significant variation on number of pods plant−−1 of blackgram (table 2). table 2. effect of variety, leaf clipping and combination of treatment on the above ground dry weight/plant (g), pod length (cm) and pod plant−−1 of blackgram treatment above ground dry weight/plant (g) pod length (cm) pods plant−1 (no) 15 das 30 das 45 das at harvest variety v1 1.52b 4.45b 5.03c 6.38c 7.66b 11.75c v2 1.51b 4.11c 6.40b 7.65b 7.82b 13.32b v3 1.62a 5.51a 7.84a 9.50a 8.99a 14.00a lsd(0.05) 0.08 0.18 0.30 0.52 0.38 0.54 leaf clipping c0 1.59a 4.76ab 6.48a 8.73a 8.16ab 12.11c c1 1.57a 4.78a 6.40ab 7.98b 8.44a 15.18a c2 1.51b 4.63b 6.63a 7.45c 8.04b 12.91b c3 1.52b 4.61b 6.19b 7.22c 7.95b 11.89c lsd(0.05) 0.06 0.14 0.24 0.40 0.31 0.40 combination of treatment v1c0 1.59 ab 4.51 cd 4.84 e 7.19 de 7.83 cd 11.47 de v1c1 1.49 bc 4.61 c 4.80 e 6.20 fg 7.92 cd 12.40 c v1c2 1.48 bc 4.31 d-f 5.57 d 5.94 g 7.49 d 12.13 cd v1c3 1.51 bc 4.39 c-e 4.89 e 6.17 fg 7.42 d 11.00 e v2c0 1.51 bc 4.14 ef 6.57 b 8.87 c 7.70 cd 12.40 c v2c1 1.58 a-c 4.17 ef 6.55 b 7.80 d 8.08 c 16.27 a v2c2 1.48 bc 4.07 f 6.49 b 7.19 de 7.56 cd 12.40 c v2c3 1.47 c 4.09 f 5.99 c 6.74 ef 7.79 cd 12.20 c v3c0 1.67 a 5.63 a 8.03 a 10.13 a 8.93 ab 12.47 c v3c1 1.64 a 5.55 ab 7.84 a 9.92 ab 9.32 a 16.87 a v3c2 1.57 a-c 5.51 ab 7.82 a 9.22 bc 9.09 ab 14.20 b v3c3 1.59 ab 5.35 b 7.68 a 8.75 c 8.63 b 12.47 c lsd(0.05) 0.11 0.25 0.42 0.70 0.53 0.70 cv (%) 4.17 3.07 3.84 5.20 3.82 3.14 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. v1: bari mash-1, v2: bari mash-2, and v3: bari mash-3, and c0: no leaf clipping (control), c1: clipping of 1st basal leaf, c2: clipping of 2nd basal leaves and c3: clipping of total apical leaves having no inflorescence the maximum number of pods plant−1 of blackgram (14.0) was observed in bari mash3 and the minimum (11.75) in bari mash-1 treatment. siddikee et al. (2018) and mane et al. (2018) was also found similar result. the maximum number of pods plant−1 of blackgram (15.18) 14 sultana et al. was observed in clipping of 1st basal leaf treatment and the minimum number of pods plant−−1 of blackgram (11.89) was observed in clipping of total apical leaves having no inflorescence which was statistically similar with no leaf clipping. the result obtained from the study was similar with the findings of mondal et al. (2011). the maximum number of pods plant−1 of blackgram (16.87) was observed in bari mash-3 with clipping of 1st basal leaf, whereas the minimum (11.00) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence treatment combinations. number of seeds pod−1 variety, leaf clipping and treatment combination has showed significant variation on the number of seeds pod−1 of blackgram (table 3). the maximum number of seeds pod−1 of blackgram (9.78) was observed in bari mash-3. in contrast, the minimum (7.93) was observed in bari mash-1. the probable reason for this may be the genetic potential of the genotype that has helped produce more seeds pod−1 on blackgram variety. the result obtained from the study was similar to the findings of sunil et al. (2020). the maximum number of seeds pod−1 of blackgram (9.32) was observed in clipping of 1st basal leaf, and the minimum (8.31) was observed in clipping of total apical leaves having no inflorescence, which was statistically similar with no leaf clipping. removal of leaves in certain levels may influence growth such as if the old or bacterial or pest infested leaves or sun burn leaves were removed, it helps the plant for saving energy, which may be translocated to the others part, which influences the yield contributing characters to plant, but if the sources were removed excessively then its cause detritions and low yield of the plant. the result obtained from the present study was similar to sultana et al. (2013). the maximum number of seeds pod-1 of blackgram (10.80) was observed in bari mash-3 with clipping of 1st basal leaf, whereas the minimum (7.27) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence treatment combinations. 1000-seed weight variety, leaf clipping and treatment combination has showed significant variation on 1000 seeds weight of blackgram (table 3). the maximum 1000-seed weight of blackgram (48.58 g) was observed in bari mash-3, and the minimum (39.0 g) was observed in bari mash-1 treatment. the probable reason for this may be the genetic potential of the genotype that has helped in producing more seeds pod−1 on blackgram variety. the maximum 1000-seed weight of blackgram (48.33 g) was observed in clipping of 1st basal leaf, and the minimum (40.33 g) was observed in clipping of total apical leaves having no inflorescence treatment. removing these relative sinks probably reduced this competition, resulting in a significant increase in 1000-seed weight (sultana et al., 2013). the maximum 1000-seed weight of blackgram (51.67 g) was observed in bari mash-3 with clipping of 1st basal leaf, whereas the minimum was observed in bari mash-1 with clipping of total apical leaves having no inflorescence treatment combination. seed yield variety, leaf clipping and treatment combination has showed significant variation on grain yield (kg ha−1) of blackgram (table 3). the maximum grain yield of blackgram (1381.70 kg ha−1) was numerically observed in bari mash-3, and the minimum (1115.50 kg ha−1) was observed in bari mash-1 treatment. this increase in seed yield of blackgram varieties might be due to the higher production efficiency that has been reflected through improvement in different yield attributing characters. sunil et al. (2020), mane et al. (2018), and jadhav et al. (2014) also found similar results in the study. the maximum grain yield of blackgram (1306.70 kg ha−1) was observed in clipping of 1st basal leaf, and the minimum (1127.30 kg ha−1) was observed in clipping of total apical leaves having no inflorescence treatment. seed yield was greater in basal 2 leaves defoliated plant (5.95 t ha−−1) than the top defoliated ones (0.90 t ha−−1) i.e., defoliation of basal four leaves effect of leaf clipping on growth and yield of blackgram 15 caused a reduction of only 35.3% seed yield than control. in contrast, the top four leaves defoliation caused a 61.6% yield reduction. these results indicate that upper leaves contribute more assimilate to the sink than the basal leaves. this is possible because upper leaves are younger, capture more sunlight than the basal leaves, and produce more assimilation. rao and ghildiyal (1985), and mariko and hogetsu (1987) was also found similar results. the maximum grain yield of blackgram (1456.70 kg ha−1) was observed in bari mash-3 with clipping of 1st basal leaf treatment combinations and the minimum (982.00 kg ha−1) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence. stover yield variety, leaf clipping and treatment combination has showed significant variation on stover yield (kg ha−1) of blackgram (table 3). the maximum stover yield of blackgram (3620.50 kg ha-1) was observed in bari mash-3, and the minimum (3290.80 kg ha−1) in bari mash-1 which was statistically similar to bari mash-2. mane et al. (2018) found similar result which supported the study. the maximum stover yield of blackgram (3651.10 kg ha−1) was observed in no leaf clipping, and the minimum (3233.30 kg ha−1) was observed in clipping of total apical leaves having no inflorescence, which was statistically similar to the clipping of 1st basal leaf treatment. the maximum stover yield of blackgram (3953.30 kg ha−1) was observed in bari mash-3 with no leaf clipping, and numerically the minimum (3073.30 kg ha-1) was observed in bari mash-1 with clipping of total apical leaves having no inflorescence combination. biological yield variety, leaf clipping and treatment combination has showed significant variation on biological yield of blackgram (table 3). the maximum biological yield of blackgram (5002.20 kg ha−1) was observed in bari mash-3, and the minimum (4406.30 kg ha−1) was observed in bari mash-1 treatment which was statistically similar to bari mash-2. the higher biological yield of bari mash-3 as compared to bari mash-1 might be due to the accumulation of more dry matter and higher biomass potential. mane et al. (2018) and siddikee et al. (2018) was also found simila results. the maximum biological yield of blackgram (4868.20 kg ha−1) was observed in no leaf clipping, which was statistically similar to clipping of 2nd basal leaves and the minimum (4360.70 kg ha-1) in clipping of total apical leaves having no inflorescence treatment. the maximum biological yield of blackgram (5313.30 kg ha−1) was observed in the bari mash-3 with no leaf clipping treatment combination, whereas the minimum in bari mash-1 with clipping of total apical leaves having no inflorescence. excess removal of source (leaves) reduced dry matter production, ultimately reducing yield. as biological yield is the combination of grains and stover yield, excess removal of leaves alters the growth, which influences the yield contributing characters as a result yield and growth were reduced. harvest index variety, leaf clipping and treatment combination has showed significant variation on harvest index (%) of blackgram (table 3). the maximum harvest index of blackgram (27.66%) was observed in the bari mash-3 whereas the minimum (25.30%) in bari mash-1 which was statistically similar to bari mash-2. jadhav et al. (2014) also reported that black gram varieties differed significantly in harvest index. the maximum harvest index of blackgram (27.80%) was observed in clipping of 1st basal leaf treatment. the minimum harvest index of blackgram (24.97%) was observed in no leaf clipping treatment, which was statistically similar to clipping of total apical leaves having no inflorescence (25.77%) treatment. biswas et al. (2005) was reported that the effect of defoliation on the harvest index varied significantly with the clipping treatments. it was higher in 33 and 66% defoliation (average of 24.5%) than in control and 100% defoliation (average of 22.7%). the maximum harvest index of blackgram (28.81%) was observed in the 16 sultana et al. bari mash-3 with clipping of 1st basal leaf treatment combination, whereas the minimum harvest index of blackgram (23.91%) was observed in the bari mash-1 with no leaf clipping treatment combination. table 3. effect of variety, leaf clipping and combination of treatment on the seeds pod−1, 1000 seed weight (g), seed yield (kg ha−1), stover yield (kg ha−1), biological yield (k g ha−1) and harvest index (%) of blackgram treatment seeds pod−1 (no.) 1000 -seed weight (g) seed yield (kg ha−1) stover yield (kg ha−1) biological yield (kg ha−1) harvest index (%) variety v1 1.52b 4.45b 5.03c 6.38c 7.66b 11.75b v2 1.51b 4.11c 6.40b 7.65b 7.82b 13.32b v3 1.62a 5.51a 7.84a 9.50a 8.99a 14.00a lsd(0.05) 0.08 0.18 0.30 0.52 0.38 0.54 leaf clipping c0 1.59a 4.76ab 6.48a 8.73a 8.16ab 12.11c c1 1.57ab 4.78a 6.40ab 7.98b 8.44a 15.18a c2 1.51b 4.63b 6.63a 7.45c 8.04bc 12.91b c3 1.52b 4.61b 6.19b 7.22c 7.95c 11.89c lsd (0.05) 0.06 0.14 0.24 0.40 0.31 0.40 combination of treatment v1c0 7.73 ef 37.33 gh 1096.70 g 3490.00 b-d 4586.70 cd 23.91 e v1c1 8.40 de 44.00 c-e 1223.30 ef 3266.70 de 4490.00 cd 27.26 a-c v1c2 8.33 de 40.00 fg 1160.00 fg 3333.30 b-e 4493.30 cd 25.82 b-d v1c3 7.27 f 34.67 h 982.00 h 3073.30 e 4055.30 e 24.22 de v2c0 9.00 cd 46.33 b-d 1194.70 ef 3510.00 b-d 4704.70 c 25.39 de v2c1 8.77 cd 49.33 ab 1240.00 de 3296.70 c-e 4536.70 cd 27.33 ab v2c2 7.93 ef 43.00 df 1206.70 ef 3486.70 b-d 4693.30 c 25.71 b-d v2c3 8.87 cd 41.67 ef 1100.00 g 3290.00 de 4390.00 d 25.06 de v3c0 9.40 bc 47.00 bc 1360.00 bc 3953.30 a 5313.30 a 25.60 c-e v3c1 10.80 a 51.67a 1456.70 a 3600.00 b 5056.70 ab 28.81 a v3c2 10.13 ab 51.00a 1410.00 ab 3592.00 bc 5002.00 b 28.20 a v3c3 8.80 cd 44.67 c-e 1300.00 cd 3336.70 b-e 4636.70 cd 28.04 a lsd (0.05) 0.74 3.99 70.03 301.21 291.56 1.72 cv (%) 4.88 5.26 3.33 5.11 3.64 3.81 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. v1: bari mash-1, v2: bari mash-2, and v3: bari mash-3, and c0: no leaf clipping (control), c1: clipping of 1st basal leaf, c2: clipping of 2nd basal leaves and c3: clipping of total apical leaves having no inflorescence conclusion from the above findings, it can be concluded that most of the growth, yield, and yieldcontributing characteristics of blackgram gave the best performance from var. bari mash-3. again, leaf clipping of 1st basal leaf showed the best performance regarding most yield and yieldcontributing characteristics. in the case of combined effect, var. bari mash-3 and clipping of 1st basal leaf gave the best result in producing the maximum pod length, number of pods plant-1, number of seeds pod-1, and 1000seeds weight, which ultimately influences seed yield. the highest seed yield was obtained from bari mash-3, and clipping of 1st basal leaf of blackgram treatment combination can be treated as the best treatment combination in this study. effect of leaf clipping on growth and yield of blackgram 17 references afzal, m.a., m.a. baker and m.l. rahman. 1999. lentil cultivation in bangladesh. lentil, blackgram and mungbean development pilot project, pulses research station, bari, gazipur-1701, bangladesh. ahmed, m.f. 2017. effect of leaf clipping and variety on growth and yield of mungbean. m. s. thesis, department of agronomy, sher-e-bangla agricultural university, dhaka−1207, bangladesh. bari (bangladesh agricultural research institute). 2019. ‘krishi projukti hathboi’. bangladesh agricultural research institute, joydebpur, gazipur, bangladesh. p.68. bbs (bangladesh bureau of statistics). 2021. statistical pocket book of bangladesh. mins. planning govt. peoples repub. bangladesh. p.143. biswas, m.i., m.a. hossain and m.s.a. fakir. 2005. effect of defoliation at vegetative stage on dry mass production and yield in cowpea. j. bangladesh agril. univ. 3(1): 13-20. echarte, l., f.h. andrade, v.o. sadras and p. abbat. 2006. kernel weight and its response to source manipulations during grain filling in argentinean maize hybrids released in different decades. field crops res. 96(2): 307-312. gomez, m.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons, new york. pp.97–129, 207–215. hies. 2010. preliminary report of household income and expenditure survey. bangladesh bureau of statistics, ministry of planning, gob, dhaka, bangladesh. jadhav, p.b., d.r. kamble, k.t. jadhav and d.l. gadpale. 2014. performance of black gram (vigna mungo l. hepper) varieties to different sowing dates. adv. res. j. crop improv. 5(2): 166-171. mane, r.b., b.v. asewar, y.e. kadam and k.v. deshmukh. 2018. correlation studies in weather parameters and yield of black gram varieties under changing weather conditions. bull. env. pharmacol. life sci. 7: 37-42. manoj k.n., m.r. umesh, y.m. ramesh, s.r. anand and s. angadi. 2019. dry matter production and radiation use efficiency of pulses grown under different light conditions. bangladesh j. bot. 48(1): 9-15. mariko, s. and k. hogestu. 1987. analytical studies on the responsed of sunflower (helianthes annus) to various defliation treatments. ecol. res. 2: 1-17. mondal, m.m.a., m.a. rahman, m.b. akter and m.s.a. fakir. 2011. effect of defoliation during reproductive stage on yield in mungbean (vigna radiata wilczek). legume res. 34(3): 222 225. rao, t.r.k. and m.c. ghidiyal. 1985. analysis of photosynthetic source and sink relationship in mungbean (vigna radiata (l) wilezck). indian j. plant physiol. 28: 135-144. siddikee, m.r., r. sultana, m. hasan, t. rahman, a.b. siddique and a.k.m.r. amin. 2018. effect of nitrogen sources on the yield of different blackgram (vigna mungo) varieties. asian res. j. agric. 10(3): 1-8. sultana, m., b. ahmed, m.m. rahman, s. sultana and m.m. haque. 2013. growth and seed yield of mungbean as influenced by leaf clipping and fertilizer doses. bangladesh res. pub. j. 9(2): 78-86. sunil, c., p. mahadevu, g.s. yogesh, c. hanagi and a.b. mohankumar. 2020. performance of blackgram varieties under rainfed conditions of chamarajanagar district in karnataka. j. krishi vigyan. 8(2): 215-218. blank page bangladesh agron. j. 2020, 23(2): 111-117 growth, flower dropping, pod set and yield response of soybean varieties as affected by suplemental fertilizer spray at flowering n. chakma, p.k. biswas and m. hasanuzzaman department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh corresponding e-mail: nidhichakma045@gmail.com (received: 17 october, 2020, accepted: 04 december, 2020) keywords: foliar spray, urea, mop, dap, flower and pod dropping, yield, soybean abstract a field experiment was conducted during the period from january to may 2014 to study the response of growth, flower dropping, pod setting and yield of two soybean varieties to foliar fertilization of urea at early stage of flowering. soybean varieties, bari soybean-5 and bari soybean-6, were feeded with four supplemental foliar spray treatments of fertilizer, viz. m1: control i.e., no additional nutrient spray; m2: 20% of recommended urea spray at flowering; m3: 20% dose of the recommended mop; and m4: 20% dose of the recommended dap at early flowering stage. the experiment was laid out in a splitplot design with three replications. there was no significant effect of variety, fertilization spray or their interaction observed on growth parameters. however, flower and pod dropping was affected with higher flower dropping (55.2%) in bari soybean-5 and maximum pod dropping (16.44%) with dap spray treatment. higher yield attributes’ values such as seeds pod -1 (2.42), seed yield (1.18 t ha -1 ), stover yield (1.02 t ha -1 ), and biological yield (2.21 t ha -1 ) were obtained with foliar dap spray treatment. the interaction of bari soybean-5 and foliar dap spray showed the highest seed yield (1.48 t ha -1 ), stover yield (1.26 t ha -1 ) and biological yield (2.75 t ha -1 ). introduction soybean is the most important oil seed crop in the world, which belongs to fabaceae family. the crop not only provides oil, it also supplies vegetable protein to millions of people. the multipurpose use of soybean is gradually increasing day by day in bangladesh thus the cultivated area of soybean also increasing. the area harvested for soybean in bangladesh was above 62000 ha and the production was 96921 ton with average yield of 1.5 t ha -1 . however, the world average yield of soybean was about 2.9 t ha -1 (faostat, 2018). the reason for low yield rate of soybean is mainly due to use of low yielding varieties and insufficient agronomic management (khanam et al., 2016). experimental evidences reveal that soybean is highly responsive to different fertilizers and its yield can be increased remarkably through the judicious fertilization (bari, 1988; mohamed, 1984; kazi et al., 2002). soybean yield depends on number of pods produced per unit area and seed weight. the number of pods depend on the number of floral buds which attain maturity. although the crop produces abundant flowers, but a large proportion of them drop away during development (kokubun, 2011). according to shibles et al. (1975), the flower and pod dropping rate were estimated to reach 80%. reduction of flower and pod dropping rate is an important factor in increasing yield of soybean. generally, essential plant nutrients are applied as a basal dose during land preparation to attain maximum yield of a crop. although soil application is the most effective method, but under some circumstances foliar fertilization is more effective and economic (fageria et al., 2009). 112 chakma et al. foliar spraying is helpful when crop roots are unable to provide enough nutrients and much more economic since foliar application rate is less compared to soil application. many researchers reported that supplemental nutrients applied at different reproductive stages of crop through foliar application increases the yield of soybean. specially, at early flowering or pod initiation stage, soybean requires more nutrients for the development of pod and seed along with optimum soil moisture (dandge et al., 2018). it is suggested that nitrogen (n) is the determinant of seed production for crops with high seed n content (kinugasa et al., 2012). rigorous researches are still necessary to identify and specify the right nutrients for highest potential yield of soybean. the experiment was undertaken to investigate the influence of foliar nutrient spray on flower and pod droppings of soybean, and to study the growth and yield response of two soybean varieties towards urea, mop and dap spray at early flowering stage. materials and methods the experiment was carried out at research field of agronomy department, sher-e-bangla agricultural university, dhaka during the period of jan-may, 2014. the soil of the experimental site is belonged to the modhupur tract (aez no. 28). the topography of the experimental site was adequately uniform, leveled and soil was deep red brown terrace soil with ph 5.6. the full amount of recommended dose @ 60, 175, 120, 115 and 10 kg ha -1 of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum and boric acid respectively (frg, 2012) were applied during final land preparation. two soybean varieties, bari soybean-5 and bari soybean-6 were used for this experiment. the experiment consisted two factors and it was laid out in a split-plot design with three replications. total number of plots was 24 and the size of each unit plot was 3m  3m. two soybean varieties were assigned in the main plot, v1: bari soybean-5 and v2: bari soybean-6 and the sub-plots had four supplemental spray treatments, m1: control (no additional nutrient spray); m2: 20% of recommended urea spray at flowering; m3: 20% of recommended mop spray at flowering and m4: 20% of recommended dap spray at flowering. the supplemental spray was done at flowering stage (60 days after sowing). different intercultural operations such as thinning, irrigation, weeding and plant protection measures were done as and when needed. five plants from each plot were randomly selected and different growth parameters (plant height, leaflet number, branches plant -1 and dry matter plant -1 ) were recorded at 75 das and 100 das. another five plants were randomly selected for documenting flower and pod dropping rate by using a clean paper. the harvesting was done when 90% of the pods become brown in color and the plants were harvested from 5.4 m 2 central area of each plot. yield attributes such as no. of pods plant -1 , no. of seeds pod -1 , grain yield, stover yield and harvest index were recorded at the time of harvesting. the collected data were statistically analyzed by using statistix 10 statistical program and the significant differences were compared by the least significant difference (lsd) test at 5% level of probability (gomez and gomez, 1984). results and discussion growth parameters the growth parameters of two soybean varieties didn’t show any significant variation in regards of effect of variety, fertilization, and interaction of variety x fertilizers at 75 das and 100 das (table 1). while in terms of variety, bari soybean-5 performed comparatively better for plant height (57.57 cm and 58.67 cm) and branch number plant -1 (4.03 and 3.62), highest dry weight plant -1 (7.59 g and 15.17 g) was recorded in bari soybean-6 at 75 das and 100 das, respectively. among the fertilizer treatments, dap fertilization (m4) showed highest plant height (55.69 cm and 58.42 cm) at 75 das and 100 das, highest branch number plant -1 (3.83) and dry weight plant -1 (16.92) at 100 das. in growth, flower dropping, pod set and yield response of soybean 113 terms of the interaction effect of variety and fertilization, v1m4 (bari soybean-5 and dap) presented highest plant height and branch number plant -1 at 75 das and 100 das, and v2m4 (bari soybean-6 + dap) produced highest dry matter plant -1 at 100 das. it seems that the combination of nitrogen and phosphorous fertilizer showed better result in soybean plants growth traits. a similar foliar spray was performed by kaur and singh (2019) at pod initiation stage with the treatments of water, urea, mop, dap, npk 19:19:19, molybdenum and zinc spray, and similarly, the treatments didn’t significantly influence the growth attributes of soybean. table 1. effect of foliar urea, mop and dap spray on different growth parameters of soybean at 75 das and 100 das treatments plant height (cm) leaflet numbers plant-1 branch number plant-1 dry weight plant-1 (g) 75 das 100 das 75 das 100 das 75 das 100 das 75 das 100 das variety v1 57.57 58.67 70.36 24.57 4.03 3.62 6.61 11.71 v2 50.11 52.23 64.40 25.50 3.62 3.42 7.59 15.17 foliar spray m1 54.68 56.23 71.50 27.60 3.90 3.33 6.62 12.40 m2 53.00 54.68 69.87 23.60 4.03 3.50 7.09 11.51 m3 51.97 52.47 62.50 23.13 3.53 3.40 7.82 12.92 m4 55.69 58.42 65.64 25.80 3.83 3.83 6.87 16.92 se 4.70 4.38 11.46 3.61 0.66 0.54 1.32 3.21 variety x foliar spray v1m1 59.09 60.80 74.40 29.80 3.93 3.20 6.09 11.46 v1m2 56.47 58.47 73.33 22.27 4.27 3.80 5.68 9.64 v1m3 54.58 54.40 63.80 19.93 3.60 3.27 8.51 8.94 v1m4 60.14 61.00 69.89 26.27 4.33 4.20 6.16 16.79 v2m1 50.28 51.67 68.60 25.40 3.87 3.47 7.15 13.35 v2m2 49.54 50.90 66.40 24.93 3.80 3.20 8.51 13.38 v2m3 49.37 50.53 61.20 26.33 3.47 3.53 7.12 16.89 v2m4 51.25 55.83 61.40 25.33 3.33 3.47 7.58 17.05 se 6.65 5.66 16.20 4.47 0.99 0.75 1.71 5.34 cv (%) 15.12 13.67 29.45 25.00 30.04 26.79 32.25 41.41 v1 = bari soybean-5, v2 = bari soybean-6, m1 = no supplemental spray, m2 = supplemental spray of urea, m3 = supplemental spray of mop, m4 = supplemental spray of dap flower and pod dropping in case of flower and pod dropping attributes, flower dropping and pod dropping displayed significant variation for two varieties and fertilizer treatments respectively. there was no statistically significant variation found among soybean variety and fertilization interaction (table 2). the maximum flower dropping (%), pod dropping (%), and total pod dropping (%) was recorded under bari soybean-5 (55.2, 15.36, and 70.56 respectively). although, highest flower dropping % (55.30) was found under urea treatment (m2), maximum pod dropping % and subsequently total dropping % (16.44, and 68.99, respectively) was found in dap treatment (m4). the highest remaining pod was found under mop treatment (m3). oko et al. (2003) reported reduced flower abortion rate in soybean when foliar urea was applied at reproductive stages compared to control. roy (2013) reported minimum flower dropping and pod dropping under supplemental irrigation + n spray before flowering 114 chakma et al. in chickpea. the result inconsistency might be due to differences in variety, soil moisture availability and subsequent treatments. table 2. effect of foliar urea, mop and dap spray on flower and pod dropping percentage of two soybean varieties treatments flower dropping (%) pod dropping (%) total dropping (%) pod remaining (%) variety v1 55.2 a 15.36 70.56 29.45 v2 50.89 b 13.89 63.87 35.96 foliar spray m1 52.61 14.22 ab 66.83 32.84 m2 55.3 12.93 b 68.24 31.76 m3 51.73 14.93 ab 64.82 35.22 m4 52.56 16.44 a 68.99 31.01 se 3.78 1.12 4.38 4.42 variety x foliar spray v1m1 55.36 16.31 71.67 28.33 v1m2 55.77 12.58 68.35 31.65 v1m3 52.81 16.66 69.47 30.59 v1m4 56.87 15.89 72.77 27.23 v2m1 49.86 12.13 61.98 37.35 v2m2 54.83 13.29 68.13 31.87 v2m3 50.64 13.19 60.16 39.84 v2m4 48.24 16.98 65.22 34.78 se 4.65 3.63 6.1 6.21 cv (%) 12.35 13.27 11.29 23.41 v1 = bari soybean-5, v2 = bari soybean-6, m1 = no supplemental spray, m2 = supplemental spray of urea, m3 = supplemental spray of mop, m4 = supplemental spray of dap maximum flower dropping and total dropping was found in v1m4 (bari soybean-5 x dap spray) and consequently, minimum pod remaining was found in the same interaction. the lowest total dropping was recorded under v2m3 (bari soybean-6 + mop) and consequently, maximum remained was found under same interaction (table 2). yield and yield attributes among the yield attributes, pod length, seed yield and biological yield showed significant differences for two soybean varieties, while other yield attributes didn’t show any significant differences (table 3). the higher pods number plant -1 and harvest index was recorded in bari soybean-6 and higher pod length (cm), seeds pod -1 , 1000-seed weight, seed yield, stover yield and biological yield was found in bari soybean-5. among the fertilizer treatments, seeds pod -1 and 1000-seed weight showed significant differences for different foliar fertilization at early flowering stage. the highest pods number plant -1 (57.72), pod length (3.47 cm), and harvest index % (59.01) was recorded under mop treatment (m3), however, highest number of seeds pod -1 , highest stover yield, and biological yield was found in dap treatment (m4). a similar result was obtained by vinoth kumar et al. (2013), where highest number of pods plant -1 , number of seeds pod -1 , grain yield was recorded under 2% dap treatment. singh et al. (2018) growth, flower dropping, pod set and yield response of soybean 115 also performed a similar experiment at pod initiation stage and reported highest pods plant -1 and seed yield under 2% dap spray. the interaction effect of variety and fertilizer showed statistically significant differences in seeds pod -1 , pod length, seed yield, and biological yield. the maximum seeds pod -1 (2.48) was recorded from v1m3 (bari soybean-5 + mop) which was statistically similar (2.43) to v1m4 (bari soybean-5 + dap). on the other hand, maximum seed yield (1.48 t ha -1 ) and biological yield (2.75 t ha -1 ) was recorded from v1m4 (bari soybean-5 + dap at flowering). the harvest index didn’t show any significant variation among interaction treatments; however, maximum harvest index was found from v2m2 (bari soybean-6 + urea spray at early flowering). table 3. effect of foliar urea, mop and dap spray on yield attributes of two soybean varieties treatments pods plant-1 (no.) pod length (cm) seeds pod-1 (no.) 1000seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) variety v1 50.33 3.51 a 2.41 103.47 1.29 a 1.03 2.32 a 55.56 v2 60.45 3.36 b 2.36 95.9 0.95 b 0.71 1.66 b 57.38 foliar spray m1 55.67 3.44 2.33 c 104.04 a 1.03 0.81 1.84 55.37 m2 54.43 3.43 2.37 b 102.39 ab 1.21 0.91 2.11 57.94 m3 57.72 3.47 2.41 ab 96.59 b 1.07 0.73 1.79 59.01 m4 53.73 3.41 2.42 a 95.74 b 1.18 1.02 2.21 53.54 se 9.24 0.04 0.02 3.13 0.19 0.14 0.29 3.24 variety x foliar spray v1m1 53.73 3.44 bc 2.29 d 111.33 1.17 ab 0.91 2.08 ab 55.01 v1m2 46 3.49 b 2.42 b 104.33 1.28 ab 1.13 2.40 ab 53.47 v1m3 56.23 3.68 a 2.48 a 98.66 1.21 ab 0.82 2.03 ab 59.35 v1m4 45.33 3.41 bc 2.43 ab 99.57 1.48 a 1.26 2.75 a 54.41 v2m1 57.6 3.44 bc 2.37 b 96.74 0.88 b 0.71 1.59 b 55.74 v2m2 62.87 3.36 cd 2.33 cd 100.44 1.13 ab 0.69 1.81 b 62.42 v2m3 59.2 3.25 d 2.34 cd 94.52 0.92 b 0.64 1.56 b 58.67 v2m4 62.13 3.41 bc 2.4 b 91.91 0.87 b 0.78 1.66 b 52.58 se 13.42 0.05 0.03 4.42 0.23 0.21 0.38 5.74 cv (%) 28.91 1.87 1.39 5.43 28.85 27.2 26.03 9.94 v1 = bari soybean-5, v2 = bari soybean-6, m1 = no supplemental spray, m2 = supplemental spray of urea, m3 = supplemental spray of mop, m4 = supplemental spray of dap conclusion in conclusion, it appears that foliar application of urea, mop and dap at early flowering stage had no significant effect on plant growth traits of soybean. in case of flower & pod dropping and yield attributes, the results showed inconsistency with previous findings of other researchers. it is suggested that further study is required before recommending foliar nutrient application for optimum soybean production. 116 chakma et al. references bari (bangladesh agricultural research institute). 1988. annual report 1988-1989. bari, joydebpur, gazipur-1701, bangladesh. dandge, m.s., y.v. ingle, p.d. peshattiwar and h.h. dikey. 2018. effect of foliar nutrition on soybean productivity. intl. j. chem. stud. 6(1): 1290-1292. fageria, n.k., m.p. barbosa filho, a. moreira and c.m. guimaraes. 2009. foliar fertilization of crop plants. j. plant nutr. 32(6): 1044-1064. faostat. 2018. world food and agriculture statistical pocket book 2018. rome. p.254. frg. 2012. fertilizer recommendation guide. bangladesh agricultural research council (barc), farmgate, dhaka-1215, bangladesh. p.274. gomez, a.a. and k.a. gomez. 1984. statistical procedures for agricultural research, john wiley and sons, ink., new york. pp.207-215. kaur, v.h. and g. singh. 2019. effect of foliar fertilization at early reproductive stages on growth, productivity and profitability of soybean (glycine max (l.) merrill). appl. biol. res. 21(3): 250254. kazi, b.r., f.c. oad and a. lakho. 2002. effect of irrigation frequencies on growth and yield of soybean. pakistan j. appl. sci. 2(6): 661-662. khanam, m., m.s. islam, m.h. ali, i.m. chowdhury and s.m. masum. 2016. performance of soybean under different levels of phosphorus and potassium. bangladesh agron. j. 19(1): 99-108. kinugasa, t., t. sato, s. oikawa and t. hirose. 2012. demand and supply of n in seed production of soybean (glycine max) at different n fertilization levels after flowering. j. plant res. 125: 275-281. kokuban, m. 2011. physiological mechanisms regulating flower abortion in soybean. in: soybeanbiochemistry, chemistry and physiology, doi: 10.5772/15694. mohamed, s.a. 1984. effect of irrigation and water use efficiency of corn plants in fayoum governrate. ann. agric. sci. 20(2): 221-235. oko, b.f.d., a.e. eneji, w. binang, m. irshad, s. yamamoto, t. honna and t. endo. 2003. effect of foliar application of urea on reproductive abscission and grain yield of soybean. j. plant nutr. 26(6): 1223-1234. doi: 10.1081/pln-120020366 roy, i. 2013. influence of supplementary nitrogen, irrigation, and hormones on flower droppings, growth and yield of chickpea. masters thesis. sher-e-bangla agricultural university, dhaka, bangladesh1207. singh, a.k., c.s. singh, a.k. singh and s. karmakar. 2018. soybean productivity as influenced by foliar application of nutrients. j. pharmacog. phytochem. sp1: 413-415. shibles, r.m., i.c. anderson and a.h. gibson. 1975. crop physiology (evans, l.t., ed.) cambridge university press, london, pp.151-190. van roekel, r.j., l.c. purcell and m. salmeron. 2015. physiological and management factors contributing to soybean potential yield. field crops res. 182: 86-97. vinoth kumar, c.k. vaiyapuri, a.m. mohamed and g. gopalswamy. 2013. influence of foliar spray of nutrients on yield and economics of soybean (glycine max l. merill). j. biol. sci. 13: 563-565. https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.5772%2f15694 bangladesh agron. j. 2021, 24(2): 127-136 deep placement of npk briquette in rice: environment friendly technology for sustainable rice production a.b.s. sarker1, a.j. mridha2 and m.a. mazid miah3 1pso, agronomy division; 2agronomy division, 3ex head, soil science division bangladesh rice research institute, gazipur corresponding e-mail: sarkerabs@yahoo.com (received: 05 december 2021, accepted: 15 december 2021) keyword: usg, boro season, t. aman season, t. aus season abstract nine experiments were conducted at the bangladesh rice research institute (brri) farm, gazipur, brri regional station, sagardi, barisal and farmers’ field of barisal during boro, t. aus and t. aman season, 2012 to evaluate the npk briquette efficacy in rice production. experimental results revealed that deep placement of npk briquette (2 x 2.4 g) increased rice grain yield about 10 % and it saves 51, 9 and 20 kg npk ha-1 than brri fertilizer recommended rate in boro season. similarly, npk briquette (1 x 3.4 g) produced 28 and 18% more rice grain yield than brri fertilizer recommended rate with a savings of 29 kg n and 7 kg k ha-1 in t. aus and t. aman season, respectively. in general, deep placement method gave higher grain yield compared to conventional urea application. undiscounted benefit cost ratio (bcr) was 1.44, 2.40 and 3.20 for boro, t. aus and t. aman, respectively when comparing at the same rates of n application. thus, use of npk briquette over urea broadcast and incorporation was economically viable and efficient for rice cultivation. this method helps to reduce n loss through soil-water interface which plays a vital role in reducing environmental pollution. introduction rice is the most extensively cultivated crop in bangladesh and staple food of bangladeshi people also. bangladesh is an agro-based country and predominantly rice based one which earns about 21.10% of her gross domestic product (gdp) from agriculture (anonymous, 2008). the area and the production of rice in this country are 11.25 million hectares and 29.75 million tons, respectively (ais, 2008). the edaphic and climatic factors of bangladesh are favorable for rice cultivation but the average yield of boro rice in this country is quite low (2.55 t ha-1) in the fiscal year of 2006-2007 (bbs, 2007). the farmers have to produce maximum rice from minimum land by adopting improved agronomic practices. deep placement of npk briquette can play a significant role in increasing yield of boro rice. bhuiyan et al. (1988) reported that deep point placement of usg resulted in significantly higher grain yield of rice than split application of prilled urea. further increases in grain yield, better n use efficiency (kg grain /kg n) and higher apparent n recovery occurred when the hole was closed after usg application. similarly, mohanty et al. (1999) reported that usg deep placement resulted additional grain yield of 1080, 510 and 350 kg/ha over prilled urea in alternate wetting and drying, shallow low land and intermediate low land, respectively. recent increase in the cost of inorganic fertilizer makes it important to examine the relationships between grain yield and n utilization by rice to improve the efficiency of n utilization. many strategies have been developed to increase the efficiency of urea-n use from fertilizer through proper timing, rate, deep placement, modified forms of fertilizer, and use of nitrification and urease inhibitors. among them deep placement of urea fertilizer is one of the most effective application method in reducing total mailto:sarkerabs@yahoo.com 128 sarker et al. n loss in the floodwater and is likely to minimize losses through volatilization and surface runoff (de datta & craswell, 1982). similarly, kapoor et al. (2008) reported that broadcast application of n as urea resulted in an average ten times higher amounts of ammonium n in flood water compared to deep placement of urea briquette. they also reported that deep placement of p and k resulted in lower content of p and k in floodwater. in rice cultivation system generally, p and k fertilizer is applied as broadcast but an npk briquette is applied by deep point placement. for very low level of p and k in soil, particularly under upland condition, initial broadcast application followed by deep point placement to each subsequent planting is generally recommended. the use of urea briquettes gave higher rice yields and resulted in greater removal of npk than prilled urea (prasad and prasad, 1983). kapoor et al. (2008) reported that deep placed n-p briquettes gave significantly higher rice grain yield, total p and k uptake. they also found that closer spacing (20 cm x 10 cm) led to better utilization of p and k and provided opportunities for deep placement of n-p or n-p-k briquettes in soils with low available p. bulbule et al. (2008) reported that grain yield of rice significantly increased when the crop was fertilized through briquettes (56-30-30 kg npk/ha) as compared to the application of conventional fertilizers (100-50-50 kg npk/ha). the deep placement of npk briquette combines the concept of balance fertilization and deep placement advantage towards higher nutrient use efficiency in rice. in this context, npk briquette deep placement technology for higher rice yield as well as better utilization of applied fertilizer by the crop and indirectly to avoid environmental pollution through volatilization and surface runoff to be ascertained. materials and methods nine field experiments were conducted at brri farm gazipur, brri regional station, sagordi, barisal and farmer’s field at babuganj of barisal by agronomy division of brri. eight treatments were tested. the treatments were t1 = brri recommended dose of prilled urea at three splits and p k s and zn fertilizer was applied as basal at final land preparation, t2 = one 2.70 g usg (n78 ) in boro and one 1.90 g usg (n52) was placed at the centre of each four hills + brri recommended rate p k s and zn fertilizer was applied as basal at final land preparation, t3 = 2.40 g npk briquette (two in boro, one in t. aus and t. aman) was placed at the centre of each four hills (n:p:k ratio = 7.0:1.6:2.0 and doses of npk = 87 kg nha-1, 20 kg pha-1 and 25 kg kha-1 in boro and 43.5 n kg nha-1, 10 kg pha-1 and 12.5 kg kha-1 in t aus and t. aman, s and zn as recommended, t4 = one 3.40 g npk briquette was placed at the centre of each four hills (n:p:k ratio = 9.1:2.4:3.5 and doses of npk = 57 kg nha-1, 15 kg pha-1 and 22 kg kha-1 ) and s and zn as recommended, t5 = npks and zn doses were same as t3 but sources were urea, tsp, mp, t6 = npks and zn doses were same as t4 but sources were urea, tsp, mop, t7 = absolute control and t8 = n alone for prilled urea. the nutrients of the treatments for the location and season are given in table 1. the experiment was laid down in rcb design with three replications. the tested variety was brri dhan29 in boro, brri dhan27 in t aus and brri dhan49 in t. aman season. the unit plot size was 4 x 6 m. transplanting was done by two seedlings per hill and the seedling age was 40, 30 and 35 days, respectively in boro, t. aus and t. aman season at plant spacing of 20 cm x 20 cm. all fertilizer was applied as per treatment before and after transplanting. the usg and npk briquettes were deep placed between four hills as per treatment after 7 days of transplanting. table 1. summary of treatments applied at different locations and across seasons treatments description location season n rate (kg/ha) p rate (kg/ha) k rate (kg/ha) t1= rec. fertilizer rate brri recommend on-station (gazipur)) boro 138a 26b 75b aus 77a 15b 37b aman 93a 16b 42b on-station (barisal) boro 138 30 30 aus 77 11 17 aman 93 15 17 on-farm boro 138 30 30 deep placement of npk briquette in rice: environment friendly technology 129 (babuganj) aus 77 11 18 aman 93 15 18 t2 = usg n78 kg ha-1 + rec. pkszn usg (one-2.7 g briq) all all 78c pk rate similar as t1 in respective season t2 = usg n52 kg ha-1 + rec. pkszn usg (one-1.8 g briq) all t. aus and t. aman 52 t3 = (2x2.40) npk briquette n87 npk (two-2.4 g briq) all boro 87c 20c 25c t3 = (1x2.40) npk briequette n44 npk (one-2.4 g briq) all t. aus and t. aman 43.5c 10c 12.5c t4 = 3.40 g npk briequette n57 npk (one-3.4 g briq) all all 57c 15c 22c t5 = npk same at t3 from urea, tsp and mop npk (urea,tsp, mop) all boro 87a 20b 25b npk (urea, tsp, mop) all t. aus and t. aman 43.5a 10b 12.5b t6 = npk same at t4 from urea, tsp and mop npk (urea, tsp, mop) all all 57a 15b 22b t7 = abs. control absolute control all all 0 0 0 t8 = only n n alone all all 102 25d 64d placement of usg and npk briquette was done 10 days after transplanting. flood water nh4-n was determined through spectrophotometer by using nessler reagent (radov et al., 1985) and continued for seven days. grain yield (t/ha) was determined from 5m2 from each treatment and straw yield per square meter was calculated from 16 hills. the data were statistically analyzed. table 2. treatment description for boro rice treatments description n rate (kg/ha) p rate (kg/ha) k rate (kg/ha) basal /deep placed n (kg/ha) 1st topdress n (kg/ha) 2nd topdress n (kg/ha) t1 check 0 25a 64b 0 0 0 t2 usg (one-2.7 g briq) 78 25a 64b 78 0 0 t3 usg (two-1.8 g briq) 104 25a 64b 104 0 0 t4 urea 78 25a 64b 26 26 26 t5 urea 104 25a 64b 34 35 35 t6 npk (two-2.4 g briq) 78 16c 42c 78 0 0 t7 urea 156 25a 64b 52 52 52 t8 npk (two-3.4 g briq) 102 25d 64d 102 0 0 a applied as tsp, b applied as mop (kcl), c p and k is applied as npk briquette (treat. 6; made with 45 kg urea + 27 kg dap + 28 kg mop), d p and k is applied as npk briquette (treatment 8; made with 40 kg urea + 30 kg dap + 30 kg mop) table 3. treatment description for t. aus and t. aman rice treatments description n rate (kg/ha) p rate (kg/ha) k rate (kg/ha) basal /deep placed n (kg/ha) 1st topdress n (kg/ha) 2nd topdress n (kg/ha) t1 check 0 16a 42b 0 0 0 t2 usg (one-1.8 g briq) 52 16a 42b 52 0 0 t3 usg (one-2.7 g briq) 78 16a 42b 78 0 0 t4 urea 78 16a 42b 26 26 26 t5 udp (two-1.8 g briq) 104 16a 42b 104 0 0 t6 npk (one-3.4 g briq) 51 13c 32c 51 0 0 130 sarker et al. t7 urea 120 16a 42b 40 40 40 t8 npk (two-2.4 g briq) 78 16d 42d 78 0 0 a applied as tsp, b applied as mop (kcl), c p and k is applied as npk briquette (treat. 6; made with 45 kg urea + 27 kg dap + 28 kg mop), d p and k is applied as npk briquette (treatment 8; made with 40 kg urea + 30 kg dap + 30 kg mop) results and discussion grain yield of nine locations with all treatments of boro, t. aus and t. aman are presented in table 46 and grain yield advantage (%) over recommended fertilizer rate is shown in table 7. brri recommended fertilizer rate (npkszn) produced higher grain yield than without fertilizer and n alone treatment irrespective of locations and seasons. the only exception was observed for the first cropping (boro) at babuganj where n alone treatment with available soil p and k gave similar yield as the brri recommended treatment. overall, the highest grain yields were obtained with the deep placement of npk briquette at all locations. during the boro season t3 (two-2.4 g npk briquette) which was three locations average 10.06% higher. during the t. aus and t. aman season t4 (one-3.4 g npk briquette) gave the highest grain yield and it was three locations average 17.69% higher in t aus and 27.99% in t aman season (table 7). table 4. effect of different treatments on the grain yield of brri dhan29 during boro season 2012 at different locations treatments boro on-station (gazipur) on-station (barisal) on-farm (barisal) t1 = rec. fertilizer rate 7.00 b 6.99 ab 6.67 bc t2 = usg n52 kg ha-1 + rec. pkszn 7.13 ab 7.15 a 7.03 b t3 = (2 x 2.40) npk briqutte n87 7.47 a 7.29 a 7.94 a t4 = 3.40 g npk briqutte n57 5.92 c 6.43 b 6.13 c t5 = npk same at t3 from urea, tsp and mop 6.96 b 6.89 ab 7.16 b t6 = npk same at t4 from urea, tsp and mop 6.12 c 6.26 b 6.22 c t7 = absolute control 3.89 d 3.20 c 4.14 d t8 = only n 5.88 c 6.19 b 6.88 bc figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by dmrt table 5. effect of different treatments on the grain yield of brri dhan49 during t aman season 2012 at different locations treatments t. aman on-station (gazipur) on-station (barisal) on-farm (barisal) t1 = rec. fertilizer rate 4.20 bc 4.77 bc 4.40 b t2 = usg n52 kg ha-1 + rec. pkszn 4.44 b 5.26 ab 4.94 ab t3 = (1x2.40) npk briqutte n44 3.89 c 5.54 ab 4.22 b t4 = 3.40 g npk briqutte n57 4.85 a 5.70 a 5.19 a t5 = npk same at t3 from urea, tsp and mop 3.27 d 4.68 bc 4.01 bc t6 = npk same at t4 from urea, tsp and mop 4.03 d 4.70 bc 4.37 b t7 = absolute control 2.96 e 3.60 d 3.16 d t8 = only n 3.30 d 4,29 cd 3.55 cd deep placement of npk briquette in rice: environment friendly technology 131 figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by dmrt table 6. effect of different treatments on the grain yield of brri dhan27 during t.aus season 2012 at different locations treatments t. aus on –station (gazipur) onstation (barisal) on-farm (barisal) t1 = rec. fertilizer rate 3.24 c 2.84 d 2.73 b t2 = usg n52 kg ha-1 + rec. pkszn 3.57 b 3.34 b 2.90 b t3 = (1x2.40) npk briquette n44 3.20 c 3.10 c 2.96 b t4 = 3.40 g npk briquette n57 3.93 a 3.58 a 3.72 a t5 = npk same at t3 from urea, tsp and mop 2.96 d 2.80 d 2.72 b t6 = npk same at t4 from urea, tsp and mop 3.18 c 3.04 c 2.87 b t7 = absolute control 2.13 e 2.02 e 2.38 d t8 = only n 2.51 d 2.47 d 2.51 cd figures in a column means followed by different letters differ significantly, whereas figure with common letter(s) are not significantly different at the 5% level by dmrt table 7. effect of different treatments on the grain yield advantage over recommended fertilizer rate average of three locations during boro, t aman and t. aus season treatments average yield increase in boro over recommend rate (%) average yield increase in t. aman over recommend rate (%) average yield increase over recommend rate (%) t1 = rec. fertilizer rate 0.0 0.00 0.00 t2 = usg n52 kg ha-1 + rec. pkszn 3.25 11.43 9.41 t3 = npk briquette n87 (boro) and n44 (t. aus and t. aman) 10.06 5.47 1.85 t4 = 3.40 g npk briquette n57 -10.51 27.99 17.69 t5 = npk same at t3 from urea, tsp and mop 1.82 -4.45 -10.97 t6 = npk same at t4 from urea, tsp and mop -9.89 3.49 -2.02 t7 = abs. control -45.51 -25.21 27.45 t8 = only n -8.04 14.50 16.83 npk briquette deep placement increased rice grain yield when compared with urea broadcast and incorporation during boro season at three locations with equivalent n87 rate (fig. 1) with same pk level. similar yield increase was also observed in all locations in both t. aus and t. aman season (fig. 2-5). in figures 3 and 5-6, a single 3.4 g npk briquette deep placement (n57 rate) is compared with same rate of n, p, and k applied as urea, tsp and mop for t. aus, aman and boro season respectively. the npk rates were low for the boro rice; hence there was no difference between deep placement of npk and the conventional application (fig. 6). however, for both the t. aus and t. aman crop npk briquette deep placement produced higher yield than conventional application of npk (fig. 3 and 5). the results indicate that the deep placement of npk briquette has some yield advantage over urea, tsp, and mop application at equivalent rate in wetland rice culture system. in boro season deep placement of npk briquette with 87 kg n/ha produced higher yield than the higher level of brri recommended n138 rate (fig. 7). it means deep placement method saved on an overage 51-9-20 kg npk/ha across location with increase of 10% rice yield in boro season. similarly, t. aus and t. aman season also showed 28 and 18% yield increase with less fertilizer as npk briquette deep placement as compared to higher level of brri recommended n rate (figure 8-9). 132 sarker et al. fig. 1. influence of npk briquette and urea-n at equivalent rate (n87) on the yield of brri dhan29 in boro season at different locations. fig. 2. yield comparison between npk briquette and urea-n at equivalent rate (n44) at different locations in t. aus season. again, deep placement method saved n fertilizer 20 kg/ha in t. aus and 36 kg/ha in t. aman season. based on these results it may be concluded that npk briquette deep placement in wet land rice culture enhanced rice yield with less amount of fertilizer than using the conventional method of urea, tsp and mop application. deep placement of npk briquette in rice: environment friendly technology 133 fig. 3. influence of npk briquette and urea-n at equivalent rate (n57) on the yield of brri dhan27 in t. aus season at different locations. fig. 4. yield comparison between npk briquette and urea-n at equivalent rate (n44) at different locations in t aman season. fig. 5. yield comparison between npk briquette and urea-n at equivalent rate (n57) on the yield of brri dhan49 at different locations in t aman season. 0 1 2 3 4 5 6 7 hq,gazipur rs, barisal ff,barisal location y ie ld (t /h a) npk briq-n57 urea-n57 fig. 6. yield comparison between npk briquette and urea-n at equivalent rate (n57) with same level of pk on the yield of brri dhan29 in boro season. 134 sarker et al. fig. 7. comparison of grain yield between recommended fertilizer rate (n138) and npk briquette (n87) deep placement in boro season at different locations. fig. 8. comparison of grain yield between recommended fertilizer rate (n77) and npk briquette (n57) deep placement during t aus season at different locations. fig. 9. grain yield comparison between recommended fertilizer rate (n93) and npk briquette (n57) deep placement during t aman season at different locations. deep placement of npk briquette in rice: environment friendly technology 135 a partial budget analysis was done to determine the economic benefit of npk briquette over urea broadcast and incorporation. table 4 revealed that additional yields obtained from npk briquette deep placement were 577, 713 and 880 kg/ha in boro, t. aus and t. aman season, respectively and thus additional returns (tk./ha) were tk. 8655, tk. 10695 and tk. 13200, respectively. on the other hand, by using npk briquette for rice production additional cost were incurred tk. 3540, tk. 3144 and tk. 3144 in boro, t. aus and t. aman production, respectively. therefore, in all seasons, positive net returns were obtained from npk briquette placement for rice cultivation. table 7 also showed that undiscounted bcr (3.20) were highest in t. aman production followed by t. aus production (2.40). finally, it may conclude that use of npk briquette over urea broadcast and incorporation was economically viable and efficient for rice production. table 7. partial budget analysis of npk briquette for rice production in different seasons over urea broadcast and incorporation season npk briquette additional yield (t/ha) additional return (tk./ha) additional cost (tk./ha) total cost (tk./ha) net return (tk./ha) undiscounted bcr cost for briquette manuf. labor requirement boro 2.4g: 8720-25 577 8655 1140 2400 3540 5115 1.44 t. aus 3.4g: 5715-22 713 10695 744 2400 3144 7551 2.40 t. aman 3.4g: 5715-22 880 13200 744 2400 3144 10056 3.20 note: estimated price of paddy was tk. 15/kg, manufacturing cost of npk briquette was tk. 6/kg, labor required for npk briquette placement was 8 man-day /ha and wage rate of labor was tk. 300/day experimental result revealed that deep placement method of npk briquette in rice production saved 51 kg n/ha in boro and around 29 kg n/ha in t. aus and t. aman season. deep placement method favors to obtain higher yield compared to urea application to some extend. undiscounted benefit cost ratio (bcr) was 1.44, 2.40 and 3.20 for boro, t. aus and t. aman rice, respectively. conclusion deep placement of npk briquettes (2 x 2.4g) increased about 10% higher rice grain yield and saved 51, 9 and 20 kg npk/ha than brri fertilizer recommended rate in boro season. similarly, 23% more rice yield obtained from npk briquette (1 x 3.4 g) use than brri recommended fertilizer rate with a savings of 28 kg n and 7 kg k /ha irrespective of t. aus and t. aman season. npk briquette use also promotes balance fertilization in rice production. deep placement of npk briquette leads to the accumulation of nutrients in the reduced zone of soil and subsequently these nutrients are utilized efficiently by rice plants for better growth and increased yield. this method leads to a significant decrease in flood water nh4-n content and the resultant effect decrease the load of volatilization and surface runoff and ultimately reduces environmental pollution and it may be considered as environment friendly technology. references ais (agriculture information service). 2008. krishi diary (in bengali). khamarbari, new airport road, farmgate, dhaka, bangladesh. p.23. anonymous. 2008. economic advisory sub-division. economic division. minist. plan. govt. people's repub. bangladesh. p.132. barber, s.a. 1976. efficient fertilizer use. in: patterson f. l ed. pp.13-29. agronomic research for food. madison. wi asa special publication no. 26. amer. soc. agron. 136 sarker et al. bbs (bangladesh bureau of statistics). 2007. statistical year book of bangladesh bureau of statistics, stat. div., min. plan., govt. people's repub., bangladesh, dhaka. pp.47-50. bhuiyan, n.i., a.l. shah, m.a. saleque and s.k. zaman. 1988. effect of n source and application method on dry season irrigated rice. irrn 13(3): 28. bulbule, a.v., a.g. durgude, v.s. patil and kulkarnil. 2008. fertilization of low land transplanted rice through briquettes. crop res. 35(1& 2): 1-5. de datta, s.k. and e.t. craswell. 1982. nitrogen fertilizer and fertilizer management in wet land rice soils. in rice research strategies for the future, international rice research institute. los banos, laguna, philippines, pp.283-316. fan xiao-hui, s.yong-sheng, l. de-xi, y. lin-zhang and l. jia-fa. 2006. ammonia volatilization losses and 15n balance from urea applied to rice on a paddy field. j. env. sci. 18 (2): 299-303. irri (international rice research institute). 2006. rice yield (t ha-1), by country and geographical region. world rice statistics. intl., rice res. inst. los banos, laguna, philippines. pp.1-8. kapoor, v., u. singh, s.k. patil, h. magre, l.k. shrivastava, v.n. mishra, r.o. das, samadhiya, j. sanabria and r. diamond. 2008. rice growth, grain yield, and flood water nutrient dynamics as affected by nutrient placement method and rate. agron. j. 100(3): 526-536. mitsui, s. 1955. inorganic nutrition, fertilization and soil amelioration for low land rice. 2nd ed. yokendo press, tokyo, japan 105p. mohanty, s.k., u. singh, v. balasubramanian and k.p. jha. 1999. nitrogen deep-placement technologies for productivity, profitability, and environmental quality of rainfed lowland rice systems. nutr. cycl. agro ecosys. 53: 43-57. prasad, m. and r. prasad. 1983. removal of nitrogen, phosphorus and potassium by rice-wheat double cropping system as affected by duration of rice variety, methods of planting rice and levels and sources of nitrogen. plant soil. 70: 287-295. radov, a.s., i.v. pustovoi and a.v. korolkov. 1985. practical on agrochemistry. moscow: agropromizgat. 312p. (russian). sanchez, p.a. 1976. properties and management of soils in the tropics. john wiley and sons inc. 618p. shioiri, m. 1941. denitrification in paddy soils. (in japanese.) kagaku (science in japan) 16: 104-116. 1pso, agronomy division; 2agronomy division, 3ex head, soil science division bangladesh rice research institute, gazipur corresponding e-mail: sarkerabs@yahoo.com keyword: usg, boro season, t. aman season, t. aus season abstract nine experiments were conducted at the bangladesh rice research institute (brri) farm, gazipur, brri regional station, sagardi, barisal and farmers’ field of barisal during boro, t. aus and t. aman season, 2012 to evaluate the npk briquette efficacy i... introduction materials and methods results and discussion experimental result revealed that deep placement method of npk briquette in rice production saved 51 kg n/ha in boro and around 29 kg n/ha in t. aus and t. aman season. deep placement method favors to obtain higher yield compared to urea application t... conclusion references bangladesh agron. j. 2020, 23(2): 45-49 integrated nutrient management on the yield and profitability of cauliflower s. k. bhowal 1* , m. h. hossain 2 , m. m. bashir 3 1 scientific officer, 2 principal scientific officer, 3 senior scientific officer, ofrd, bari, cumilla, bangladesh *correspondng e-mail: shamal.bau@gmail.com (received: 27 september, 2020, accepted: 27 october, 2020) keywords: integrated nutrient management, cauliflower, yield, profitability abstract field experiments were conducted at multi location testing (mlt) sites of chandina and debidwer of cumilla district, and kasba of brahmanbaria district under on-farm research division (ofrd), bangladesh agricultural research institute, cumilla during 2016-18 to find out the appropriate dose of fertilizer for the maximum productivity of hybrid cauliflower varieties. five integrated nutrient management packages such as t1= recommended fertilizer dose for high yield goal (hyg), viz. 40-20-38-7-0-0 npksznb kg ha -1 , t2= t1 + 1.5 t ha -1 vermicompost, t3 = t1 + 5 t ha -1 cowdung, t4= stb (107-61107-30-3.0-1.0 npksznb kg ha -1 and t5= farmers practices (114-74-123.5-0-0 npksznb kg ha -1 ) were used in the trial. the experiment was laid out in a randomized complete block (rcb) design with six dispersed replications. the result revealed that the highest curd breadth (21.68 cm), individual curd weight (1.86 kg) and curd yield (44.14 t ha -1 ) was obtained from t2 treatment followed by t3 and t4 treatments. the lowest yield was found from farmers practice. similarly the highest gross return (tk. 626669.00 ha -1 ) and gross margin (tk. 493869.00 ha -1 ) were also found from t2 treatment and the lowest (tk. 457734.00 ha -1 and 438066.00 ha -1 ) respectively from farmer's practice t5. introduction cauliflower (brassica oleracea var. botrytis l.) is the most popular cruciferous vegetable among the cole crops. the crop is the native of south europe in the mediterranean region and was introduced in india from england in 1822 (chatterjee and swarup, 1972). the edible part of cauliflower ‘curd’ which is prefloral fleshy apical meristem. it is cultivated for its attractive curd which is used as raw cocked vegetables, curries, soups and pickles. it is predominant due to its attractive appearance, good taste, easy digestible, rich source of nutrients and high yielding capacity. it is a major source of protein, calcium, phosphorus, potassium, sodium, iron and vitamins. like other vegetable crops of the family, cauliflower is a heavy feeder of mineral elements, it removes large amount of macronutrients from the soil. heavy manuring has been recommended for getting good yield of cauliflower by different workers in india (roy, 1981, randhawa and khurana, 1983). mineral nutrition plays an important role in influencing the quality of crops and it is fact that the soil health deteriorates due to continuous use of chemical fertilizers, (savci, 2012). the integrated nutrient management paves the way to overcome these problems, which involves conjunctive use of chemical fertilizers and organic manures to sustain crop production as well as maintenance of soil health (nanjappa et al., 2001). systematic approach to nutrient management by tapping all possible sources of organic and inorganic in a judicious manner to maintain soil fertility and crop productivity is the essence of integrated nutrient management (inm) (chowdhury et al., 2014). mailto:shamal.bau@gmail.com 46 bhowal et al. farmers in bangladesh produces cauliflower in the field ignoring the adequate and rational use of fertilizers. the inorganic fertilizer is much expensive for the common farmers and also hazardous to the soil environment. to combat the problems, it is necessary to adopt integrated nutrient management practices in cauliflower production for boosting up the safe production. considering the above facts, this experiment was initiated to find out an integrated fertilizer (inorganic and organic) dose for the maximum production of cauliflower. materials and methods the experiment was conducted at mlt sites barura, chandina and brahmanbaria under on-farm research division of bangladesh agricultural research institute, cumilla during rabi 2016-18 to find out the integrated fertilizer (inorganic and organic) dose for the cultivation of cauliflower. five integrated nutrient management packages for cauliflower cultivation such as t1= recommended fertilizer dose for hyg (40-20-38-7-0-0 npksznb kg ha -1 (frg, 2012) t2= t1 + 1.5 t ha -1 vermicompost, t3 = t1 + 5 t ha -1 cowdung, t4= stb (107-61-107-30-3.0-1.0 npksznb kg ha -1 and t5= farmers practices (114-74-123.5-0-0 npksznb kg ha -1 ) were used in the trial. the experiment was laid out in randomized complete block (rcb) design with six dispersed replications. unit plot size was (4.0 m  5.0 m) 20 m 2 and the variety hybrid fulkupi atlas 777 was used. seedlings were transplanted at the main field maintaining row to row and plant to plant distance 60 cm and 40 cm, respectively in last week of october to first week of november in both the years. fertilizers were applied on the basis of experimental treatments. dolochun was applied @ 1 t ha -1 in the whole experimental field. all intercultural and pest control measures were done as and when necessary. harvesting of cauliflower was done on 2nd to 3rd weeks of january. initial soil properties of the farmer’s field during 2017-18 are presented in table 1. data on yield and yield parameters of cauliflower were recorded and analyzed statistically at 5 % level of probability using statistical program statistix10 and presented in the table 3. cost of production was calculated on the basis of cost of land preparation, seed cost, fertilizer cost, pesticide cost, labor cost and land rent are presented in the table 4. chemical composition of manures used in the study table 1 summarized the results of chemical analysis of the vermicompost and cowdung manure used in the study. nutrients status of vermicompost was higher than cowdung. the soil quality includes soil reaction (ph) and mineral nutrient elements has been presented in table 2. table 1. chemical composition of cowdung and vermicompost organic manure ph om (%) total-n (%) available p (μg/g soil) exchangeable k (meq/100g) available s (μg/g soil) vermicompost 7.3 18.30 0.72 251.31 0.73 409.81 cowdung 8.2 12.27 0.56 196.64 0.65 81.10 integrated nutrient management on the yield and profitability of cauliflower 47 table 2. initial and post-harvested soil properties of the farmer’s field soil properties land type ph organic matter (%) k meq100 ml-1 total n (%) p s b µgml-1 initial mhl 5.2 2.40 0.12 0.12 5 2 0.28 post-harvested soils t1 mhl 4.48 2.89 33.88 0.17 7.21 61.06 0.27 t2 mhl 4.66 3.09 41.47 0.16 10.36 49.91 0.40 t3 mhl 4.51 3.17 41.00 0.16 9.24 36.56 0.36 t4 mhl 4.95 3.92 29.54 0.20 7.09 32.35 0.30 t5 mhl 4.59 2.45 22.1 0.17 8.21 19.11 0.32 critical level 0.12 0.12 10 10 0.20 source: srdi regional laboratory, cumilla, note: t1= recommended fertilizer dose for hyg (frg-2012), t2= t1 + 1.5 t ha -1 vermicompost, t3 = t1 + 5 t ha -1 cowdung, t4= stb and t5= farmers practices results and discussion yield and yield attributing characters yield components and curd yield of cauliflower under different integrated fertilizer management practices are presented in table 3. the result showed that there is no significant difference among t1, t2 and t3 treatments regarding the curd length. the shortest curd length (22.23cm) was recorded in t4 treatment, which was statistically similar to farmers fertilizer management practice. the maximum curd breadth (21.68 cm) was found in t2 but it was statistically similar with t1 and t3. individual curd weight of cauliflower differed significantly under different organic and inorganic fertilizer management practices. the maximum individual curd weight was recorded from t2 (1.86 kg) that was followed by t3 and t4 treatments and minimum in t1 (1.47 kg) i.e. frg 2012. there was no significant variation in plant population m -2 , but numerically highest was in t3 and lowest in t5 treatment. the result reveled that among the different integrated nutrient management practices the maximum curd breadth (21.68 cm) and individual curd weight (1.86 kg) was found in t2 that was statistically similar with t3 treatment (table 3). similar result was also reported by sharma et al. (2019) who stated that integrated use of fertilizer, manure and bio fertilizer improves soil fertility and crop growth of cole crops. so, the highest curd yield (44.14 t ha -1 ) was also obtained from t2 treatment and minimum curd yield was documented from farmer's practice. the variation in curd yield of cole crops were also observed by kayesh et al. (2019) and dey et al. (2018) who explains that it may be attributed to the total dry matter production and its partitioning to different yield contributing organs. table 3. effect of different organic and inorganic fertilizer packages on yield and yield contributing characters of cauliflower at cumilla and brahmanbaria (av. 2016-18) treatments curd length (cm) curd breadth (cm) individual curd weight. (kg.) plant population (no.) curd yield (t ha-1) t1 23.19 20.23 1.47 3.02 39.25 t2 24.59 21.68 1.86 3.15 44.14 t3 24.74 20.91 1.65 3.28 41.43 t4 22.23 19.18 1.58 3.13 41.04 t5 22.89 18.74 1.48 2.84 32.47 cv (%) 3.52 5.69 9.87 11.29 8.79 lsd (0.05) 1.56 2.16 0.30 ns 6.57 note: t1= recommended fertilizer dose for hyg (frg-2012), t2= t1 + 1.5 t ha -1 vermicompost, t3 = t1 + 5 t ha 1 cowdung, t4= stb and t5= farmers practices 48 bhowal et al. cost and return analysis cost and return analysis of different nutrient management packages of cauliflower has been presented in table 4. from cost and return analysis it was revealed that the gross return, total cultivation cost and gross margin varies with different fertilizer management practices. results showed that gross return (tk. 626669.00 ha -1 ) and gross margin (tk. 493869.00 ha -1 ) was highest in t2 treatment that received 1.5 t ha -1 vermicompost with recommended fertilizer dose for hyg (frg, 2012) and the lowest in farmer's practice. the findings of mahamud (2006) and salwa (2019) agreed with that the combination of inorganic fertilizers with organic fertilizers would plays a vital role to ensure safe and economic food production. table 4. economic analysis of cauliflower as affected by different integrated nutrient management packages at cumilla and brahmanbaria (average) treatments gross return (tk. ha-1) total cost of cultivation (tk. ha-1) gross margin (tk. ha-1) t1 557018.00 140900.00 416118.00 t2 626669.00 132800.00 493869.00 t3 589299.00 158800.00 430499.00 t4 578966.00 140900.00 438066.00 t5 457734.00 120000.00 337734.00 price of input and output: urea tk. 16/kg, tsp tk. 22/kg, mop tk. 15/kg, gypsum tk. 10 /kg, cowdung tk. 1/kg, vermicompost tk. 15/kg and cauliflower (curd) tk. 13/kg chemical properties of soils of the experimental site the ph value of initial soil sample of the experiment was 5.2. soils of the area are loams to clays in texture having very strongly acidic to slightly acidic in reaction (frg, 2012). from the post-harvest soil analysis it was revealed that the ph values were lower than initial sample. it should be mentioned that the initial soil was collected in moist condition during the period of october. for this reason, ph value may be showed high than post-harvest soils. as well as post-harvest soils were collected in dry condition during the period of february, after harvesting of the crop. organic matter (%) of postharvest soils was higher than initial sample. nutrients status of % total n, available p, exchangeable k, available s and b of post-harvest soils were higher than initial soils sample (table 2). this nutritional change occurred due to the addition of vermicompost and cowdung in the experimental plots. the changes of the chemical properties of initial and post-harvested soils was also mentioned by ali et al. (2018) who stated that vermicompost in addition to inorganic fertilizers ensured favorable chemical properties of soil for the production of cauliflower. farmers’ opinion farmers’ opined that they did not know the soil test based fertilizer application method and other integrated fertilizer management practices for cauliflower production. they expressed that the higher yield of cauliflower could be possible by integration of organic and chemical fertilizers. conclusion based on the experimental results it was concluded that combination of organic and chemical fertilizer package viz., 1.5 t ha -1 vermicompost with recommended fertilizer dose for hyg had the maximum integrated nutrient management on the yield and profitability of cauliflower 49 positive effect on plant growth, yield and yield contributing characters of cauliflower. judicious application of organic manure in combination with chemical fertilizers is essential for yield maximization of cauliflower. references ali, s., m.a. kashem and m.m.h. sarker. 2018. effect of vermicompost on the growth and yield of cauliflower in acid soil of bangladesh. j. sylhet agril. univ. 5(1): 37 43. chaterjee, s.s. and v. swarup. 1972. indian cauliflower has as till greater future. indian hort. 10: 18-20. chowdhury, m.m.u., i.s.m. farhad, s.k. bhowal, s.k. bhowmik and a.k. choudhury. 2014. fertilizer management for maximizing soybean (glycine max l.) production in char lands of bangladesh. the agriculturists. 12(2): 98-102. dey, p., s. srivastava, n.k. lenka, k.c. shinogi, a.k. vishwakarma and a.k. patra (eds.). 2018. saarc training manual on integrated nutrient management for improving soil health and crop productivity, icar-indian institute of soil science, bhopal, india. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council (barc), farmgate, dhaka. kayesh, e., m.s. sharker, m.s. roni and u. sarker. 2019. integrated nutrient management for growth, yield and profitability of broccoli. bangladesh j. agril. res. 44(1): 13-26. mahamud, m.s. 2006. effect of different sources of nutrients on the growth and yield of broccoli (cv. ‘premium crop’) and cauliflower (cv. ‘bari 1’). ms thesis, faculty of agriculture, sher-ebangla agricultural university, dhaka. nanjappa, h.p., b.r. ramchanrappa, and b.o. mallikarjuna. 2001. effect of integrated nutrient management on yield and nutrient balance in maize. indian j. agron. 46(4): 668-701. randhawa, k.s. and d.s. khuraha. 1983. effect of nitrogen, phosphorus and potassium fertilization on the yield and quality of cauliflower. veg. sci. 10(1): 1-7. roy, h. k. 1981. effect of nitrogen on curd size and yield of cauliflower. veg. sci. 8(2): 75-78. salwa, m. and m.a. kashem. 2019. effect of nutrient management on growth and yield of cauliflower hybrids in haor area. bangladesh agron. j. 22(1): 95-104. savci, s. 2012. an agricultural pollutant: chemical fertilizer. intl. j. environ. sci. dev. 3(1): 77-80. sharma, a., s. singh and a. saurabh. 2019. a review: integrated nutrient management in cole crops. j. pharmacog. phytoche. sp4: 07-08. bangladesh agron. j. 2021, 24(1): 13-23 effect of late seeding warmer condition on phenology and yield of wheat s. sharmin, m.a. hasan and s. sikder department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur 5200, bangladesh corresponding e-mail: seulisharminhstu@gmail.com (received: 11 december 2020, accepted: 10 january 2021) keywords: cell membrane thermostability, heat susceptibility index, phenology, yield, wheat abstract four wheat variety/genotype (bari gom-26, baw-1202, baw-1182 and bari gom-27) were tested under three heat stress regimes (normal, moderate and severe) to evaluate the effect of late seeding warmer condition on phenology and yield of wheat, as well as to identify suitable cultivars to develop heat-tolerant genotypes at hajee mohammad danesh science and technology university (hstu), dinajpur during november, 2016 to april, 2017. results revealed that genotype baw-1182 and baw-1202 showed greater thermostability of cell membrane with acceptable yield performance under heat stress condition. the order of tolerance based on heat susceptibility index (based on grain yield) was baw-1182>baw-1202>bari gom27>bari gom-26 under heat stress conditions. thus, baw-1182 and baw-1202 have the greatest potential to be used as high-yielding wheat genotypes under warm to hot environments and could be used in a breeding programme to develop heattolerant wheat. introduction wheat (triticum aestivum l.) is an important cereal crop ranking number one globally and number two in bangladesh both in terms of production and acreage. generally, wheat is sown in mid-november to ensure optimal crop growth and avoid high-temperature stress. however, about 60% of the wheat is cultivated in late sowing conditions after harvesting the transplanted aman rice (baharuddin et al., 1994). an important limitation to wheat productivity is the heat stress that affects different growth stages, specially anthesis and grain filling as evident from late sowing (din et al., 2010). despite the low yield of wheat due to terminal heat stress, its cultivation cannot be avoided totally. the adverse effect of temperature can be minimized by breeding heat-tolerant genotypes that could be sown late with a high grain yield. in this context, this study aimed to evaluate the effect of late seeding warmer condition on phenology and yield of wheat genotypes followed by screening high-temperature stress-tolerant traits of wheat genotypes in the breeding program. materials and methods the experiment was set up at hajee mohammad danesh science and technology university (hstu), dinajpur during november, 2016 to april, 2017. the experimental site was situated under the dinajpur sadar upazila and located at 25º39′ n latitude and 88º41′ e longitude with an elevation of 37.58 meter above sea level. the experimental field was a medium high land mailto:seulisharminhstu@gmail.com 14 sharmin et al. belonging to the non calcareous dark grey floodplain soil under the agro-ecological zone (aez-1) of the old himalayan piedmont plain. three growing conditions -normal sowing in november 20, moderate heat stress sowing in december 20 and severe heat stress sowing in january 10 were placed in the main plots whereas four wheat variety/genotypes: bari gom26, baw-1202, baw-1182 and bari gom-27 were placed in sub-plots following split-plot design. seeds were sown in rows of 20 cm apart, at the rate of 120 kg ha-1. a fertilizer dose of 140-35-75-18-2-0.5 kg ha-1 n, p, k, s, zn and b was applied following fertilizer recommendation. phenological stages like anthesis, physiological maturity were observed and recorded in days when 50% of plants of each plot reached a definite stage (zadoks et al., 1974). cell membrane thermostability test was done as described by blum and ebercon (1981). heat susceptibility index (s) was calculated for yield as following fischer and maurer (1978). data were collected on yield and yield contributing characters of wheat. the data were analyzed by partitioning the total variance with the help of a computer using the mstatc program. the treatment means were compared using tukey’s test at a 5% level of significance. results and discussion late sown (20 december and 10 january sown) wheat genotypes exposed to heat stress (>20oc) during most of their reproductive growth phase but the wheat genotypes sown on 20 november experienced more or less 20oc temperature throughout their whole reproductive growth phase and considered as normal growing condition (fig. 1). the optimum temperature for wheat crop growth is about 20oc (al-khatib and paulsen, 1984). temperature in the range of 20 to 25oc has been considered favorable for wheat seed germination, seedling emergence and optimum plant establishment (behl et al., 1993). fig. 1. maximum, minimum and mean air temperature from 01 november 2016 to 30 april 2017 showing the period of anthesis and maturity of normal, moderate heat stress and severe heat stress. phenology days to anthesis days required to anthesis were significantly influenced by the interaction effect of growing conditions and wheat genotypes (table 1). under the normal growing condition, baw-1182 effect of late seeding on phenology and yield of wheat 15 required the highest number of days (73 days) for anthesis which was followed by bari gom-27 (72 days) and bari gom-26 (72 days) whereas baw-1202 required the lowest number of days (66 days) for anthesis. due to late seeding warmer conditions (both at moderate and severe heat stress conditions) anthesis occurred earlier than normal growing condition in all the wheat genotypes except in baw-1202 at moderate heat stress condition. but earliness of anthesis due to heat stress conditions (both at moderate and severe heat stress conditions) were not similar for all wheat genotypes at moderate and severe heat stress conditions. delay in sowing (both at moderate and severe heat stress conditions) decreased the number of days required to anthesis. days to anthesis required a lower number of days under heat stress conditions and similar results were found by dias et al. (2009) and nahar et al. (2010). table 1. effect of late seeding warmer condition and wheat genotypes on days to anthesis genotypes days to anthesis (days) growing conditions normal moderate heat stress severe heat stress v1 (bari gom-26) 72 ab 69 bc 60 d v2 (baw-1202) 66 c 69 bc 59 d v3 (baw-1182) 73 a 69 bc 62 d v4 (bari gom-27) 72 ab 70 ab 60 d level of significance ** cv (%) 1.65 means followed by the same letter(s) did not differ significantly at 5% level by mstatc program. ** significant at the 1% probability level physiological maturity days required to physiological maturity were significantly influenced by the interaction effect of growing conditions and wheat genotypes (table 2). under the normal growing condition, bari gom-26, baw-1182 and bari gom-27 required the highest number of days (106 days) for physiological maturity whereas baw-1202 required the lowest number of days (100 days) for physiological maturity. due to late seeding warmer conditions (both at moderate and severe heat stress conditions) physiological maturity occurred earlier compared to the normal growing condition in all the wheat genotypes. but earliness of anthesis due to heat stress conditions (both at moderate and severe heat stress conditions) were not similar for all wheat genotypes. hossain et al. (2011, 2012a) and hakim et al. (2012) also found that the duration of maturity of spring wheat genotypes reduced by high temperature stress in northern bangladesh. the increasing temperature during grain tended to stop grain growth prematurely and to hasten physiological maturity. a similar result was found by amrawat et al. (2013). table 2. effect of late seeding warmer condition and wheat genotypes on physiological maturity genotypes physiological maturity (days) growing conditions normal moderate heat stress severe heat stress bari gom-26 106 a 100 b 95 c baw-1202 100 b 96 c 90 d baw-1182 106 a 102 b 95 c bari gom-27 106 a 102 b 90 d level of significance ** cv (%) 0.88 means followed by the same letter(s) did not differ significantly at 5% level by mstatc program. ** significant at the 1% probability level 16 sharmin et al. cell membrane thermostability cell membrane thermostability (cmt) of flag leaf at 18 days after anthesis differed among the wheat genotypes tested (fig. 2). the highest cell membrane thermostability was found in baw1202 (53.8%) which was followed by bari gom-26 (53.1%). on the other hand, baw-1182 (42.8%) showed moderate cell membrane thermostability and bari gom-27 (29.7%) showed the lowest cell membrane thermostability. the results indicated that the wheat genotypes baw1202 and bari gom-26 were more tolerant against heat stress conditions than baw-1182 and bari gom-27. genotypic differences in membrane injury of flag leaf at anthesis of the fieldgrown wheat were also reported by hasan et al. (2007) and mohi-ud-din et al. (2007). fig. 2. cell membrane thermostability of different wheat genotypes at 18 days after anthesis. tillers m-2 tillers per m2 of four wheat genotypes at different growing conditions are presented in table 3. results showed that the interaction effect of growing conditions and wheat genotypes on tillers m-2 was significant. under the normal growing condition, baw-1202 showed the maximum tillers m-2 (332.3) which was statistically similar to bari gom-27 (320.2). genotype baw-1182 (275.3) showed the lowest number of tillers m-2 which was statistically similar to bari gom-26 (273.0). under moderate heat stress condition, bari gom-27 showed the highest tillers m-2 (336.3). baw-1182 showed moderate (296.7) which was statistically similar to baw1202 (278.8). bari gom-26 showed the lowest tillers m-2 (226.3). under severe heat stress condition, bari gom-27 showed the maximum tillers m-2 (215.8) which was statistically similar to baw-1202 (214.5). genotype baw-1182 (179.0) showed moderate tillers m-2 and lowest in bari gom-26 (107.7). table 3. effect of late seeding warmer condition and wheat genotypes on tillers m-2 genotypes tillers m-2 (no.) growing conditions normal moderate heat stress severe heat stress bari gom-26 273.0 c 226.3 d 107.7 f baw-1202 332.3 a 278.8 c 214.5 d baw-1182 275.3 c 296.7 bc 179.0 e bari gom-27 320.2 ab 336.3 a 215.8 d level of significance ** cv (%) 4.33 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. ** significant at the 1% probability level effect of late seeding on phenology and yield of wheat 17 spikes m-2 spikes per m2 of four wheat genotypes at different growing conditions are presented in table 4. results showed that the interaction effect of growing conditions and wheat genotypes on spikes m-2 was significant. under the normal growing condition, baw-1202 showed the maximum spikes m-2 (327.5) which was statistically similar to bari gom-27 (315.8). genotype baw1182 (268.3) showed the lowest number of spikes m-2 which was statistically similar to bari gom-26 (270.0). under moderate heat stress conditions, bari gom-27 showed the highest spikes m-2 (327.2). genotype baw-1182 showed moderate (290.3), which was statistically similar to baw-1202 (272.5). bari gom-26 showed the lowest spikes m-2 (239.5), which was also statistically similar to baw-1202 (272.5). under severe heat stress conditions, bari gom26 showed the maximum spikes m-2 (240.7) which was statistically similar to baw-1202 (209.8). genotype baw-1182 showed the lowest spikes m-2 (174.8), which was statistically similar to bari gom-27 (176.7). bari gom-27 is also statistically similar to baw-1202. results from other studies showed that spike number plant-1 was not significantly influenced by late sowing (hasan et al., 2007). hu and rajaram (1994) reported that spike number plant-1 was less sensitive while the yield, grains spike-1, biomass and plant height were more sensitive to high temperature. table 4. effect of late seeding warmer condition and wheat genotypes on spikes m-2 genotypes spikes m-2 (no.) growing conditions normal moderate heat stress severe heat stress bari gom-26 270.0 cd 239.5 de 240.7 de baw-1202 327.5 a 272.5 cd 209.8 ef baw-1182 268.3 cd 290.3 bc 174.8 g bari gom-27 315.8 ab 327.2 a 176.7 fg level of significance ** cv (%) 4.21 means followed by the same letter(s) did not differ significantly at 5% level by mstatc program. ** significant at the 1% probability level spikelets spike-1 spikelets spike-1 of four wheat genotypes at different growing conditions is presented in table 5. results showed that the interaction effect of growing conditions and wheat genotypes on spikelets spike-1 was significant. table 5. effect of late seeding warmer condition and wheat genotypes on spikelets spike-1 genotypes spikelets spike-1 (no.) growing conditions normal moderate heat stress severe heat stress bari gom-26 18.83 bcd 21.47 a 18.30 bcd baw-1202 17.57 d 20.00 ab 18.23 bcd baw-1182 19.07 bcd 21.67 a 19.43 bc bari gom-27 18.13 cd 18.53 bcd 17.30 d level of significance * cv (%) 3.06 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. * significant at the 5% probability level 18 sharmin et al. under the normal growing condition, baw-1182 showed the maximum number of spikelets spike-1 (19.07), which was statistically similar to bari gom-26 (18.83), bari gom-27 (18.13) and baw-1202 (17.57). genotype baw-1202 showed the lowest number of spikelets spike-1. under moderate heat stress conditions, baw-1182 showed the maximum number of spikelets spike-1 (21.67) which was statistically similar to bari gom-26 (21.47) and baw-1202 (20.00). bari gom-27 showed the lowest spikelets spike-1 (18.53), which was also statistically similar to baw-1202 (20.00). under severe heat stress condition, baw-1182 showed the maximum number of spikelets spike-1 (19.43), which was statistically similar to bari gom-26 (18.30) and baw-1202 (18.23). bari gom-27 showed the lowest (17.30) which was also statistically similar to bari gom-26 and baw-1202. grains spike-1 grains spike-1 at different growing conditions are presented in table 6. from the results it was observed that grains per spike were significantly influenced by growing conditions. irrespective of growing conditions, normal growing conditions showed the maximum grains spike-1 (50.20) which was statistically similar to moderate heat stress (49.14) whereas severe heat stress showed the lowest grains spike-1 (42.32). due to heat stress, grains per spike were decreased in severe heat stress condition (15.70%) and moderate heat stress condition (2.11%). sowing of seed at normal growing conditions may have enjoyed a longer duration and favorable temperature for growth and development as compared to others and produced a maximum number of grains spike-1. heat stress, singly or in combination with drought, is a common constraint during anthesis and grain filling stages in many cereal crops of the temperate region (nahar et al., 2010). grains spike-1 of four wheat genotypes are presented in table 7. from the results it was observed that grains spike-1 were significantly influenced by wheat genotypes but the combined effect insignificant. in the case of variety /genotype, bari gom-26 had the highest grains spike-1 (54.80) where baw-1182 had a moderate number (49.00) which was statistically similar to bari gom-27 (44.30). genotype baw-1202 showed the lowest number of grains spike-1 (40.78) which was also statistically similar to bari gom-27. significant differences among the genotypes for the number of grains spike-1 were found in wheat (falaki et al., 2009) and it may be due to the variation in the genetic potential. grain weight spike-1 grain weight spike-1 of four wheat genotypes at different growing conditions is presented in table 6. results showed that the interaction effect of growing conditions and wheat genotypes on grain weight spike-1 was significant. under the normal growing conditions, baw-1182 showed the maximum grain weight (2.51 g), which was statistically similar to bari gom-26 (2.42 g) and bari gom-27 (2.24 g). genotype baw-1202 showed the lowest grain weight (2.14 g) which was also statistically similar to bari gom-26 (2.42 g) and bari gom-27 (2.24 g). under moderate heat stress conditions, bari gom-26 showed the highest grain weight (2.69 g) whereas baw-1182 showed moderate weight (2.21 g) but similar to baw-1202 (2.16 g). bari gom-27 showed the lowest grain weight (1.60 g). under severe heat stress condition, bari gom-26 showed the maximum grain weight (1.82 g), which was statistically similar to baw-1182 (1.68 g) and baw-1202 (1.64 g). bari gom-27 showed the lowest grain weight (1.25 g). significant variations were observed among the genotypes in the reduction of grain weight spike-1 under heat stress of 26°c mean temperature (fokar et al., 1998). effect of late seeding on phenology and yield of wheat 19 table 6. effect of late seeding warmer condition and wheat genotypes on grain wt. spike-1 genotypes grain wt. spike-1 (g) growing conditions normal moderate heat stress severe heat stress bari gom-26 2.42 abc 2.69 a 1.82 de baw-1202 2.14 cd 2.16 bcd 1.64 e baw-1182 2.51 ab 2.21 bc 1.68 e bari gom-27 2.24 bc 1.60 ef 1.25 f level of significance ** cv (%) 5.63 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. ** significant at the 1% probability level 1000-grain weight the 1000-grain weight at different growing conditions is presented in table 7. from the results, it was observed that 1000-grain weight was significantly influenced by growing conditions. in the case of growing conditions, normal growing conditions showed the highest 1000-grain weight (48.11 g) and moderate heat stress showed medium 1000-grain weight (40.82 g), whereas severe heat stress showed the lowest 1000-grain weight (36.32 g). delayed sowing shortened the duration of each developmental phase, which ultimately reduces the grain filling period and lowers the grain weight (spinks et al., 2004). the 1000-grain weight of four wheat genotypes is presented in table 7. from the results it was observed that 1000-grain weight was significantly influenced by wheat genotypes but the combined effect was insignificant. irrespective of genotypes, baw-1202 showed the maximum 1000-grain weight (46.82 g), which was statistically similar to bari gom-26 (43.51 g) and bari gom-27 showed the lowest 1000-grain weight (35.03 g). again, baw-1182 (41.65 g) was moderate in weight and statistically similar to bari gom-26 (43.51 g). reduced grain size under heat stress conditions might be due to the rapid reduction in grain growth duration. the net effect of heat stress in the grain filling period was lower grain weight due to the reduction in grain filling period, grain filling rate or combined effect of both (tashiro and wardlaw, 1989). table 7. effect of late seeding warmer condition and genotypes on grains spike-1 and 1000grain wt. treatments grains spike-1 (no.) 1000-grain wt. (g) growing conditions normal 50.20 a 48.11 a moderate heat stress 49.14 a 40.82 b severe heat stress 42.32 b 36.32 c level of significance ** ** cv (%) 5.71 6.63 genotypes bari gom-26 54.80 a 43.51 ab baw-1202 40.78 c 46.82 a baw-1182 49.00 b 41.65 b bari gom-27 44.30 bc 35.03 c level of significance ** ** cv (%) 7.61 8.52 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. ** significant at the 1% probability level 20 sharmin et al. grain yield the grain yield of four wheat genotypes at different growing conditions is presented in table 8. results showed that the interaction effect of growing conditions and wheat genotypes on grain yield was significant. at normal growing conditions, bari gom-26 produced the maximum grain yield (361.0 g m-2), which was statistically similar to bari gom-27 (315.7 g m-2). bari gom-27 also statistically similar to baw-1202 (285.7 g m-2) whereas baw-1182 (242.7 g m-2) gave the lowest grain yield which was identical to baw-1202 (285.7 g m-2). under moderate heat stress conditions, baw-1202 (270.0 g m-2) attained the maximum grain yield, which was statistically similar to baw-1182 (254.7 g m-2), bari gom-27 (227.7 g m-2) and bari gom-26 (226.3 g m-2). under severe heat stress condition, baw-1202 (202.0 g m-2) gave the maximum grain yield, which was statistically similar to baw-1182 (181.0 g m-2) and bari gom-27 (152.3 g m-2). bari gom-26 (140.0 g m-2) showed the lowest grain yield, which was statistically similar to baw-1182 (181.0 g m-2) and bari gom-27 (152.3 g m-2). results from other studies showed that in the case of late sowing, climate and soil moisture were unfavorable (high temperature, low relative humidity in the air and low soil moisture) for crop production, which ultimately affected crop growth and yield (hossain et al., 2012d; hossain et al., 2013). in subtropical climates like bangladesh, excess radiation and high temperatures are often the most limiting factors affecting plant growth and final grain yield (wahid et al., 2007; hossain et al., 2009; nahar et al., 2010; hossain et al., 2011; sikder, 2011; hakim et al., 2012). biological yield the biological yield of four wheat genotypes at different growing conditions is presented in table 9. results showed that the interaction effect of growing conditions and wheat genotypes on biological yield was significant. at normal growing conditions, baw-1182 attained the highest biological yield (1701 g m-2). bari gom-26 showed moderate biological yield (1313 g m-2), which was statistically similar to baw-1202 (1299 g m-2). bari gom-27 showed the lowest value of biological yield (1178 g m-2). under moderate heat stress condition, baw-1182 (1397 g m-2) attained the highest biological yield while bari gom-26 showed the lowest (1006 g m-2) which was statistically similar to bari gom-27 (1035 g m-2) and baw-1202 (1064 g m-2). under severe heat stress conditions, bari gom-27 (808.7 g m-2) attained the highest biological yield. baw-1182 (705.3 g m-2) showed a moderate value which was statistically similar to baw-1202 (625.3 g m-2). bari gom-26 (538.0 g m-2) showed the lowest biological yield which was similar to baw-1202 (625.3 g m-2). hossain et al. (2012c) and hossain et al. (2012d) noticed that when wheat was grown from sowing to maturity at high temperatures, phenological development was rapid, leading to poor biomass production and consequently poor biological yield. table 8. effect of late seeding warmer condition and wheat genotypes on grain yield genotypes grain yield (g m-2) growing conditions normal moderate heat stress severe heat stress bari gom-26 361.0 a 226.3 def 140.0 h baw-1202 285.7 bc 270.0 bcd 202.0 efg baw-1182 242.7 cde 254.7 cd 181.0 fgh bari gom-27 315.7 ab 227.7 def 152.3 gh level of significance ** cv (%) 6.89 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. ** significant at the 1% probability level effect of late seeding on phenology and yield of wheat 21 table 9. effect of late seeding warmer condition and wheat genotypes on biological yield genotypes biological yield (g m-2) growing conditions normal moderate heat stress severe heat stress bari gom-26 1313 bc 1006 e 53 8.0 h baw-1202 1299 c 1064 e 625.3 gh baw-1182 1701 a 1397 b 705.3 g bari gom-27 1178 d 1035 e 808.7 f level of significance ** cv (%) 2.87 means followed by the same letter(s) did not differ significantly at the 5% level by the mstatc program. ** significant at the 1% probability level heat susceptibility index (hsi) heat susceptibility index (hsi) based on grain yield varied in different wheat genotypes both at moderate and severe heat stress conditions. a lower susceptibility index indicates higher tolerance. according to heat susceptibility index, the order of tolerance was baw-1182 (-0.26)>baw-1202 (0.26)>bari gom-27 (1.47)>bari gom-26 (1.95) under moderate heat stress condition and baw-1182 (0.57)>baw-1202 (0.66)>bari gom-27 (1.18)>bari gom26 (1.39) under severe stress condition. hossain and teixeira de silva (2012a) and hossain et al. (2012b) stated hsi to be a measure of yield stability. therefore, a stress-tolerant genotype as defined by hsi needs not necessarily to have a high yield potential. the ideal wheat genotype should be high yielding under any environmental conditions. fig. 4. heat susceptibility index of different wheat genotypes based on grain yield (g/m2) at moderate and severe heat stress. conclusion wheat genotypes baw-1182 and baw-1202 showed greater thermostability of cell membrane under heat stress conditions and came out with potential yield harvest. however, based on the heat susceptibility index for grain yield (under moderate and severe heat stress), baw-1182 was found as most tolerant. 22 sharmin et al. references al-khatib, k. and g.m. paulsen. 1984. mode of high temperature injury to wheat during grain development. physiol. plant. 61: 363-368. amrawat, t., n.s. solanki, s.k. sharma, d.k. jajoria and m.l. dotaniya. 2013. phenology growth and yield of wheat in relation to agrometeorogical indices under different sowing dates. african j. agric. res. 8(49): 6366-6374. badruddin, m., d.a. saunders, a.b. siddique, m.a. hossain, m.o. ahmed, m.m. rahman and s. parveen. 1994. determining yield constraints for wheat production in bangladesh. in: saunders d.a. and g.p. hettel, editors. wheat in heat stressed environments: irrigated, dry areas and rice-wheat farming systems. cimmyt, mexico.pp.265-71. behl, r.k., h.s. nainawatee and k.p. singh. 1993. high temperature tolerance in wheat. in: international crop science, crop science society of america, usa. pp.349-355. blum, a. and a. embercon. 1981. cell membrane stability as a measure of drought and heat tolerance in wheat. crop sci. 21: 4347. cimmyt. 1995. cimmyt/nars consultancy on me: bread wheat breeding. wheat special report no. 38. cimmyt, mexico, df. defra. 2005. india-uk collaboration on impacts of climate change in india. dias, a.s., a.s. baullo and fe lindon. 2009. ultrastructure and biochemical traits of bread and durum wheat grains under heat stress. brazil j. plant physiol. 20: 223-233. din, r., g. subhani, n. ahmad, m. hussain and a. rehman. 2010. effect of temperature on development and grain formation in spring wheat. pak. j. bot. 42: 89906. falaki, a.m., s. miko, i.b. mohammed, i.u. abubakar and j.a. valencia. 2009. evaluation of some improved bread wheat varieties at chiyako, jigawa state, nigeria. arpn j. agric. biol. sci. 4(4): 1-4. farooq, m., h. bramley, j.a. palta and k.h.m. siddique. 2011. heat stress in wheat during reproductive and grain-filling phases. crit. rev. plant sci. 30: 1-17. fischer, r.a. and r. maurer. 1978. drought resistance in spring wheat (triticum aestivum l.) cultivars. i. grain yield response. aust. j. agric. res. 29: 897-912. fokar, m., a. blum and h.t. nguyen. 1998. heat tolerance in spring wheat. ii grain filling. euphytica. 104: 9-15. hakim, m.a., a. hossain, j.a.t. silva, v.p. zvolinsky and m.m. khan. 2012. yield, protein and starch content of twenty wheat (triticum aestivum l.) genotypes exposed to high temperature under late sowing conditions. j. sci. res. 4(2): 477-489. hasan, m.a., j.u. ahmed, m.m. bahadur, m.m. hoque and s. sikder. 2007. effect of late planting heat stress on membrane thermostability, proline content and heat susceptibility index of different wheat cultivars. j. natn. sci. foundation sri lanka. 35(2): 109-117. hossain, a. and j.a. teixeira da silva. 2012a. phenology, growth and yield of three wheat (triticum aestivum l.) varieties as affected by high temperature stress. not. sci. biol. 4(3): 97-106. hossain, a., j.a. teixeira da silva, m.v. lozovskaya and v.p. zvolinsky. 2012c. the effect of high temperature stress on the phenology, growth and yield of five wheat (triticum aestivum l.) genotypes. asian australian j. plant sci. biotech. 6(1): 14-23. hossain, a., j.a. teixeira da silva, m.v. lozovskaya, v.p. zvolinsky and v.i. mukhortov. 2012d. high temperature combined with drought affect rainfed spring wheat and barley in south– eastern russia; yield, relative performance and heat susceptibility index. j. plant breed. crop sci. 4(11): 184-196. effect of late seeding on phenology and yield of wheat 23 hossain, a., m.a.z. sarker, m. saifuzzaman, j.a. teixeira da silva, m.v. lozovskaya and m.m. akhter. 2013. evaluation of growth, yield, relative performance and heat susceptibility of eight wheat (triticum aestivum l.) genotypes grown under heat stress. int. j. plant prod. 7(3): 615-636. hossain, a., m.a.z. sarker, m. saifuzzaman, m.m. akhter and m.s.n. mandal. 2009. effect of sowing dates on yield of wheat varieties and lines developed since 1998. bangladesh j. prog. sci. tech. 7: 5-8. hossain, a., m.a.z., sarker, m.a. hakim, m.v. lozovskaya and v.p. zvolinsky. 2011. effect of temperature on yield and some agronomic characters of spring wheat (triticum aestivum l.) genotypes. int. j. agril. res. innov. tech. 1(1&2): 44-54. hossain, a., m.v. lozovskaya, v.p. zvolinsky and j.a. teixeira da silva. 2012a. effect of soil and climatic conditions on yield-related components performance of spring wheat (triticum aestivum l.) varieties in the northern bangladesh. nat. sci. j. fund. appl. res. 2(39): 7786. hossain, a., m.v. lozovskaya, v.p. zvolinsky and j.a. teixeira da silva. 2012b. effect of soil and climatic conditions on phenology of spring wheat (triticum aestivum l.) varieties in the northern bangladesh. nat. sci. j. fund. appl. res. 2 (39): 86-97. hossain, m.m., h. takeda and t. senboku. 1995. proline content in brassica under high temperature stress. japan int. res. center agric. sci. (jircas) j. 2: 87-93. hu, z.h. and s. rajaram. 1994. differential responses of bread wheat characters to high temperature. euphytica. 72: 197-203. mohi-ud-din, m., m.a. rahman and j.u. ahmed. 2007. changes in spad value and soluble carbohydrate concentration during senescence of wheat flag leaf under heat stressed environment. j. asiat. soc. bangladesh sci. 33(2): 121-130. nahar, n., k.u. ahmed and m. fujita. 2010. phenological variation and its relation with yield in several wheat (triticum aestivum l.) cultivars under normal and late sown mediated heat stress condition. not. sci. biol. 2(3): 51-56. qin, d.h., y.h. ding and s.w. wang. 2002. a study of environment change and its impacts in western china. j. earth sci. front. 9: 321-328. sikder, s. 2011. physiological basis of heat tolerance in wheat. lap lambert acad. pub. germany. pp.1-269. spinks, p.q., h.b. shaffer, j.b. iverson and william p. mccord. 2004. phylogenetic hypotheses for the turtle family geoemydidae. mol. phylogenetics evol. 32(1): 164–182. tashiro, t. and i.f. wardlaw. 1989. a comparison of the effect of high temperature on grain development in wheat and rice. ann. bot. 64: 59-65. wahid, a., s. gelani, m. ashraf and m.r. foolad. 2007. heat tolerance in plants: an overview. environ. expt. bot. 61(3): 199-223. zadoks, j.c., t.t. chang and c.f. konzak. 1974. a decimal code for the growth stages of cereals. weed res., oxford. 14: 415-421. bangladesh agron. j. 2021, 24(1): 101-108 on-farm evaluation of production potential and economics of four crops based cropping pattern s. k. bhowal1, m. h. hossain2 and m. m. bashir3 1scientific officer, 2principal scientific officer, 3senior scientific officer, ofrd, bari, cumilla, bangladesh correspondng e-mail: shamal.bau@gmail.com (received: 11 april 2021, accepted: 21 april 2021) keywords: on-farm assessment, four crops, cropping pattern, cropping intensity, system productivity abstract a field experiment was conducted at multi-location testing (mlt) site, barura under on-farm research division (ofrd), bangladesh agricultural research institute, cumilla during 2014-16 to determine the productivity and profitability of cropping patterns, viz. boro (var. brri dhan28)-t.aus (var. brri dhan48)t. aman (var. brri dhan49)-fallow (existing cropping pattern) and boro (var. brri dhan28)-t. aus (var. brri dhan48)-t. aman (var. binadhan-11)-mustard (var. bari sarisha14) as improved cropping pattern. the results showed that improved cropping pattern provided higher amount of grain and by-product yield. the highest mean rey (18.08 t ha-1), pe (54.61 kg ha-1 day-1), lue (90.68 %) and syi (77.12%) was obtained from improved cropping pattern boro-t.aus-t. aman-mustard and the lowest (14.30 t ha-1 in 2014-15 and 13.98 t ha-1 in 2015-16) from farmers existing cropping pattern. the highest gross return (tk. 274800 ha-1 in 2014-15 and tk. 276600 ha-1 in 2015-16), gross margin (tk. 113950 ha-1 in 2014-15 and tk. 106750 ha-1 in 2015-16) and bcr (1.70 in 2014-15 and 1.66 in 2015-16) were obtained from improved four crops based cropping pattern (boro-t. aus-t. amanmustard). two years results showed that four crops could be grown one after another in a sequence in the farmers field of cumilla region for achieving higher system productivity and economic return. introduction bangladesh is a densely populated country with lower per capita arable land (12 decimal head-1) usage. the annual loss of agricultural land is about 0.73% per annum mainly due to construction of houses, roads and industrial infrastructure (bbs, 2019). thus increase of cropping intensity in rice based cropping system is becoming important for food security and poverty alleviation. a vast area remains fallow after the harvest of t. aman rice in cumilla and chandpur district of bangladesh. in near future, the main challenge is to increase 50% yield per unit land by manipulating limited resources. in order to produce more food within a limited area, the most important options are to increase the cropping intensity and to increase the production efficiency of the individual crop by using optimum management practices (mondal et al., 2015). recently with the development of short duration varieties of rice, mustard, potato, pulse and jute, opportunities have been created to accommodate four crops in same piece of land in a year (azad et al., 2020). cumilla region is highly diversified in respect to topography, agro-ecology, land-use pattern and cropping system. barura upazila occupies the highest cropping intensity (ci) of 292% followed mailto:shamal.bau@gmail.com 102 bhowal et al. by debidwar (265%) and chandina (250%) under cumilla district which are much more higher than the national average rendering those upazilas as the most intensive cropping area of the country (saha et al., 2017). cumilla is the highest rice growing district in bangladesh where boro-t. aus-t. aman-fallow is one of the major cropping patterns in the district covering of an areas of 47,350 ha (dae, 2019). rice is a promising cash crop in this region. by changing the variety of t. aman, a short duration mustard variety can be easily fitted in boro-t. aus-t. aman-fallow cropping pattern. thus it is expected that inclusion of mustard in boro-t. aus-t. aman-fallow cropping pattern would increase cropping intensity and productivity in cumilla region. further, adoption of this alternate cropping pattern boro-t. aus-t. aman-mustard can generate employment and the additional income for the rural poor of the region (hossain et al., 2017). to utilize the fallow land and to increase mustard production, it may be introduced in the fallow period before boro cultivation in the existing boro-t. aus-t. aman rice -fallow cropping pattern. potential adoption of this improved cropping pattern intensifying mustard in boro-t. aus-t. aman-fallow cropping system can generate employment and the addition of income for the rural poor and save foreign exchange for edible oil import. considering the above issues, the present study was undertaken to ascertain feasibility of growing four crops in sequence for increasing cropping intensity, productivity and income of farm families of cumilla region of bangladesh. materials and methods the experiment was conducted at folkamuri, barura under cumilla district during 2014-15 and 2015-16. the crop field was sandy loam soil and it belongs to chandina soil series under the agro ecological zone (aez)-19. initial and final chemical properties of experimental soils are presented in the table 1. the trial was conducted to derive the economic consequences of four cropping patterns viz. boro-t. aus-t. aman-mustard (improved cropping pattern) and borot. aust. aman-fallow (existing cropping pattern). the experiment was laid out in a randomized complete block design with four dispersed replications. two plots of 250 decimal were selected. one for the improved pattern and the others for farmers pattern. boro rice variety brri dhan28, t. aus rice variety brri dhan48 and t. aman rice variety binadhan-16 were used in both existing and improved cropping pattern. in the improved cropping pattern, mustard variety bari sarisha-14 was introduced against fallow period. the experimental soil was sandy loam with low organic matter content (2.26%) and soil ph was ranged 5.40-5.47 acidic in nature. the status of n, p, k, b and zn was low, optimum, low, very high and low, respectively (table 1). the experimental design was a randomized complete block with six dispersed replications. table 1. initial and final soil properties of the farmer’s field at barura, cumilla during 2014-15 and 2015-16 soil properties land type ph organic matter (%) k total n (%) p zn b meq100 ml-1soil µgml-1 initial mhl 5.47 2.26 0.14 0.16 24.5 2.91 0.24 final mhl 5.40 2.30 0.16 0.13 18.75 2.95 0.62 critical level 0.12 0.12 8. 0 0.6 0.20 analyzed by: regional soil resource development institute laboratory, cumilla; mhl: medium high land production potential and economics of four crop based cropping pattern 103 the agronomic practices used for crop production under existing and improved cropping pattern are presented in table 2. land use efficiency, production efficiency, rice equivalent yield and sustainable yield index of cropping patterns were calculated as follows: table 2. agronomic practices employed in existing and improved cropping patterns at mlt site amratoli, barura under cumilla district (average of 2014-15 and 2015 -16) parameters existing cropping pattern (ecp) improved cropping pattern (icp) crop boro rice t. aus rice t. aman rice fallow boro rice t. aus rice t. aman rice mustard variety brri dhan28 brri dhan48 brri dhan49 brri dhan28 brri dhan48 bina dhan-11 barisarish a-14 date of transplanting / sowing 26-28 january 10-13 may 15-18 august seed bed 30dec. transplanted 02 -05 feb seed bed, 16 april transplanted 07-08 may seed bed 16 july trans. 13-15 aug, 14-15 nov. seed rate (kg ha-1) 40 40 40 35 35 35 07 seedling age/days 35 30 30 32 21 28 planting method line line line line line line broadcast spacing 20 cm15cm 15 cm15cm 25 cm 15 cm 20 cm 15 cm 15 cm 15cm 20 cm15 cm broadcast fertilizer dose (npksznb, kg ha-1) 92-24-24-80.5-0 60-20-359.0-1.0-0 78-24-60-80.5-0 120-24-126.5-2.8-0 69.1-1537.5-9.61.8-0 82.9-2435-10.46.11-0 115-34-2028.8-2.511.70 fertilizer application method all pks used as basal during final land preparation. n used in 2 equal splits all pks used as basal during final land preparation. n used in 2 equal splits all pks used as basal during final land preparation. n used in 2 equal splits all pkszn and 1/3 n used as basal and rest 2/3 n used in 3 equal splits, 21 dat, 35 dat and at 45 dat. all pkszn used as basal and n used in 2 equal splits, 15 dat & at 30-35 dat. all pkszn used as basal and n used in 3 equal splits, 7 dat, 22 dat and 5-7 days before panicle initiation stage. all pkszn and half n used as basal and rest n used in 20-25 days after seed germination at prior to flowering stage. irrigation/ rainfed irrigated rainfed rainfed irrigated irrigated irrigated rainfed insect-pest control chemical chemical chemical ipm ipm ipm ipm harvesting date 26-29 april 25-27 july 02-05 dec. 23-25 april 03-05 aug 09-11 nov. 01-03 feb. field duration (days) 90-92 75-78 107-110 80-82 87-89 87-90 77-78 land use efficiency: land use efficiency is worked out by taking total duration of individual crop in a sequence divided by 365 days (tomer and tiwari, 1990). it is calculated by following formula. 104 bhowal et al. 100 365 efficiency use land 321 d + d + d  where d1, d2 and d3 the duration of first, second and third crops of the pattern. production efficiency: production efficiency values were calculated by total production in a cropping sequence divided by total duration of crops in that sequence (tomer and tiwari, 1990). 321 -1-1 321 d + d + d dayha kg. y+ y+ y efficiency production  where, y1= yield of first crop and d1= duration of first crop of the pattern y2= yield of second crop and d2= duration of second crop of the pattern y3= yield of third crop and d3= duration of third crop of the pattern sustainable yield index: sustainable yield index (syi) was computed following the formula of krishna and reddy (1997) as given below. 100 (syi)index yieldesustainabl mean mean y sd y  where, ymean: estimated mean yield of a practice over years, sd: estimated standard deviation and ymax: observed maximum yield in the experiment over the years. rice equivalent yield (rey): for comparison between crop sequences, the yield of all crops was converted into rice equivalent on the basis of prevailing market price of individual crop (verma and modgal, 1983). rice equivalent yield (t ha-1) = yield of individual crop market price of that crop market price of rice the economic indices like gross and net returns and benefit cost ratio were also calculated on the basis of prevailing market price of the produces and different operations performed and materials used for raising crops. benefit cost ratio (bcr) was calculated by the following formula: benefit cost ratio (bcr) = gross return (tk. ha-1) total cost of cultivation (tk. ha-1) rice plant was harvested at 12-20 cm height from soil surface and remaining parts of the plant was incorporated with soil. grain and byproduct yields were collected from harvested plants. the data were recorded on different parameters and presented in the table. results and discussion grain and byproduct yield of crops in cropping patterns yield of different crops in improved and existing cropping patterns are presented in table 3. improved pattern required 228-332 days against 285-288 days due to inclusion of mustard (var. production potential and economics of four crop based cropping pattern 105 bari sarisha-14) instead of fallow period in the pattern. field duration of t. aman rice (var. binadhan-11) in the improved cropping pattern was shorter due to change of variety. the yield of t. aman rice was also lower in the improved pattern than the existing cropping pattern. the yield of boro rice and t. aus rice was higher in the improved pattern than the existing cropping in both the years except boro rice in 2014-15. improved cropping pattern showed higher grain yield of boro rice by 6.20 t ha-1 in 2014-15 and 6.34 t ha-1 in 2015-16 and t. aman rice by 4.45 t ha-1 in 2014-15 and 4.35 t ha-1 in 2015-16 over existing pattern except 2015-16 in t. aman rice. higher yield of rice possibly due to improved production technologies. similar results were obtained by mandal et al. (2015), nazrul et al. (2017), khan (2018). the improved cropping pattern produced higher amount of total by-product yield (18.74 t ha-1) than the farmers’ existing pattern (15.49 t ha-1). the by-product yield of improved pattern was higher due to change of variety with improved technologies for the component crops. similar results were also documented by hossain et al. (2014) and hossain et al. (2017). mustard (var. bari sarisha14) in improved pattern produced valuable by-products in both the years. so, farmers are able to use the by-product of rice and mustard in domestic purpose and also sale in the local market with high price. table 3. productivity of existing and improved cropping patterns at mlt site amratoli, barura under cumilla district during 2014-15 and 2015 -16 productivity years ecp (existing cropping pattern) icp (improved cropping pattern) boro rice t. aus rice t. aman rice fallow boro rice t. aus rice t. aman rice mustard grain yield (t ha-1) 201415 6.39 3.48 4.43 6.20 4.29 4.45 1.69 201516 5.89 3.32 4.77 6.34 4.21 4.35 1.47 mean 6.14 3.40 4.60 6.27 4.25 4.40 1.58 by product yield (t ha-1) 201415 6.46 4.52 4.68 6.23 4.49 4.90 3.16 201516 6.32 4.42 4.58 6.19 4.63 4.76 3.12 mean 6.39 4.47 4.63 6.21 4.56 4.83 3.14 system productivity rice equivalent yield (rey) was different under different cropping sequences. the highest rey (18.08 t ha-1) was recorded from the improved cropping pattern boro-t. aus-t.aman-mustard and the lowest (14.14 t ha-1) from the existing cropping pattern i.e. borot. aust. aman (table 4). rice equivalent yield in the improved cropping pattern was higher compared to existing cropping pattern due to the inclusion of mustard with management practices. improved cropping pattern increased rey about 27.86% compared to farmers existing cropping pattern. inclusion of high yielding new variety (binadhan-11) and improved management practices in the improved pattern increased the t. aman rice equivalent yield. lower rice equivalent yield was obtained in the farmer’s pattern possibly due to traditional management practices. similar trend was noted by naher et al. (2016). maximum production efficiency (54.61 kg ha-1 day-1) was obtained from improved cropping pattern in both the years (table 4). the higher production efficiency of improved cropping pattern might be due to improved management practices. the lowest production efficiency (51.98 kg ha-1 day-1) was observed in farmers’ existing pattern 106 bhowal et al. where improved management practices easily. similar trends were noted by nazrul et al. (2013) and khan et al. (2005). the average land-use efficiency indicated that improved cropping pattern used the land for 91.52 % in 2014-15 and 89.84 % in 2015-16, period of the years, whereas farmer’s existing cropping pattern used the land for 73.47 % in 2014-15 and 75.57 % in 2015-16, period of the years (table 4). the land use efficiency was higher in improved cropping pattern because of the cultivation of mustard as fourth crop in a fallow land and longest field duration (331 days).the farmers existing pattern occupied the field for 272 days of the year. the values of sustainable yield index (syi) as a measure of sustainability of the system which was high in the improved cropping system over farmer’s practice (table 4). icp recorded the highest syi of 78.28 % in 2014-15 and 75.96 % in 2015-16 followed by ecp (70.23 % in 2014-15 and 68.15 % in 2015-16). it indicates that cropping system involving mustard in fallow period i.e four crop based improved cropping pattern recorded higher syi compared to three rice crop based farmers existing crop sequence. so, improved pattern is therefore, more stable than farmer’s pattern. short duration mustard variety bari sarisha-14 could provide special advantage regarding utilization of fallow period in cropping sequence as well as increased production of mustard. the results are in agreement with the findings of ram et al. (2012). table 4. rice equivalent yield, production efficiency, land use efficiency and sustainable yield index of existing and improved cropping patterns during 2014-15 and 2015 -16 cropping patterns years rice equivalent yield (t ha-1) production efficiency (kg ha-1 day-1) land use efficiency (%) sustainable yield index (%) ecp 2014-15 14.30 52.57 73.47 70.23 2015-16 13.98 51.39 75.57 68.15 mean 14.14 51.98 74.52 69.19 icp 2014-15 18.32 55.34 91.52 78.28 2015-16 17.84 53.89 89.84 75.96 mean 18.08 54.61 90.68 77.12 market price of mustard @ 30 tk kg-1, rice@ 15 tk kg-1, urea @ 16, tsp @ 24, mp @15,zypsum @10, zinc sulphate @ 120 and boric acid@ 150 tk kg-1, ecp = existing cropping pattern, icp = improved cropping pattern economics economic analysis was done on the basis of prevailing market price of the commodities. the gross return was different for different cropping patterns. the highest gross return (tk. 274800 ha-1) in 2014-15 and (tk. 276600 ha-1) in 2015-16 and gross margin (tk. 113950 ha-1) in 2014-15 and (tk. 106750 ha-1) in 2015-16 were obtained in improved boro-t.aus-t. amanmustard cropping pattern and the lowest gross return (tk. 214500 ha-1) in 2014-15 and (tk. 209700 ha-1) in 2015-16 and gross margin (tk. 76950 ha-1) in 2014-15 and (tk. 72150 ha-1) in 2015-16 were found in existing cropping pattern (table 5). the highest total cultivation cost (tk. 160850 ha-1 in 2014-15 and 2015-16) was recorded from cropping sequence boro-t. aus-t. aman-mustard, due to the inclusion of mustard in improved cropping pattern and the lowest (tk. 137550 ha-1 in 2014-15 and 2015-16) from the existing cropping sequence boro t. aust. aman-fallow. the highest (1.70) bcr in 2014-15 and (1.66) bcr in 2015-16 was recorded in improved boro-t. aus-t. aman-mustard cropping pattern compared to the farmers existing cropping pattern borot. aust. aman-fallow (1.55) in 2014-15 and in (1.52) in (2015-16). others (mondal et al., 2014, khan et al., 2020 and bhowal et al., 2019) agreed that production potential and economics of four crop based cropping pattern 107 the four crop based cropping pattern would play a vital role to ensure food security of the country in upcoming days. table 5. cost and return analysis of existing and improved cropping pattern at mlt site amratoli, barura under cumilla district during 2014-15 and 2015-16 cropping pattern years gross return (tk. ha-1) total cost of cultivation (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio icp 2014-15 274800 160850 113950 1.70 2015-16 276600 160850 106750 1.66 mean 271200 160850 110350 1.68 ecp 2014-15 214500 137550 76950 1.55 2015-16 209700 137550 72150 1.52 mean 212100 137550 74550 1.54 conclusion two years study revealed that four crops based cropping pattern such as boro (var. brri dhan28)-t. aus (var. brri dhan48)t. aman (var. binadhan-11)-mustard (var. bari sarisha14) is agronomically feasible and economically profitable compared to the existing farmers cropping pattern boro (var. brri dhan28)-t. aus (var. brri dhan48)-t. aman (var. brri dhan49)-fallow. so, the farmers of cumilla region could be suggested to grow mustard under four crops based cropping pattern for getting maximum profit. references bbs. 2019. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning. dhaka. bangladesh. bhowal, s.k., m.m. bashir and m.h. hossain. 2019. development of vegetable based cropping pattern in cumilla region. bangladesh agron. j. 22(1): 7-13. azad, a.k., m. miaruddin, m.a. wahab, m.h.r. seikh, b.l. nug and m.h.h. rahman. 2020. krishi projukti hatboi (handbook on agro-technology), 9th edition, gazipur-1701, bangladesh. dae. 2019. paper presented at annual research-extension regional review and program planning workshop. khamarbari, cumilla, bangladesh. mondal, r.i., f. begum, a. aziz and s.h. sharif. 2015. crop sequences for increasing cropping intensity and productivity. saarc j. agri. 13(1):135-147. mondal, r.i., f. begum and a. aziz. 2014. four crop based cropping pattern in one piece of land in a year (t. aman-mustard-boro-t. aus). (bengali booklet) bangladesh agricultural research institute, gazipur-170, bangladesh. 31p. nazrul, m.i., m.r. shaheb, m.a.h. khan and a.s.m.m.r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16(2): 41-50. nazrul, m.i., m.k. hasan and m.r.i. mondal. 2017. production potential and economics of mungbean in rice based cropping pattern in sylhet region under aez 20. bangladesh j. agril. res. 42(3): 413-424. naher, q., m.r. amin, m.r. islam, m.a. ali, a.k. choudhury, m.k. hasan and a.s.m.m.r. khan. 2016. location specific climate resilient agricultural technologies in bangladesh. ofrd (onfarm research division), bari, bangladesh. pp.37-38. 108 bhowal et al. hossain, m.h., m.m. bashir, s.k. bhowal, q. naher, t. zahan, m.k. hasan and a.s.m.m.r. khan. 2017. production technology of four crop based cropping pattern mustard-boro-t. aus-t. aman in cumilla region (bengali booklet). on-farm research division, bari, bangladesh. p.23. hossain, i., r.i. mondal, m.j. islam, a. aziz, a.s.m.m.r. khan and f. begum. 2014. four crop based cropping pattern studies for increasing cropping intensity and productivity in rajshahi region of bangladesh. bangladesh agron. j. 17(2):55-60. krishna, a. and reddy, k. 1997. production potential and economics of different rice (oryza sativa) based cropping systems in andhra pradesh. indian j. agril. sci. 67(12):551-553. khan, m.a.h., m.a. quayyum, m.i. nazrul, n. sultana and m.r.a. mollah. 2005. on-farm evaluation of production potential and economics of mustard-rice based improved cropping system. bangladesh j. socio. res. dev. 2(1): 37-42. khan, m.a.h., n. sultana, n. akter, m.s. zaman and a.k. choudhury. 2018. increasing cropping intensity and productivity through mungbean inclusion in wheat-fallow-t. aman rice cropping pattern. bangladesh j. agril. res. 43(2): 333-343. khan, m.a.h., n. sultana, n. akter, s. akhter and m.r. ali. 2020. on-farm evaluation and system productivity of garden pea-boro-t. aman rice cropping pattern in mymensingh, bangladesh agron. j. 23(1): 37-46. ram, a.j., r.a. dungrani, m.k. arvadia and k.l. sahrawat. 2012. diversification of rice (oryza sativa l.) based cropping systems for higher productivity, resource-use efficiency and economic returns in south gujarat of india. arch. agron. soil sci.58(6): 561-572. saha, a., m. nasim, m.h. rashid and s.m. sahidullah. 2017. crop diversity and cropping patterns of cumilla region. bangladesh rice j.21(2): 91-105. tomer, s.s. and a.s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35(1&2):30-35. verma, s.p. and s.c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2):89-92. microsoft word baj 349c__press bangladesh agron. j. 2020, 23(1): 13-27 performance of poultry litter based compost on morpho-physiological characters and yield of t. aman rice and soil fertility a.k.m.m.b. chowdhury1, t.s. tudu1, m.a. shohag1, m.a. hossain1 and m.z. islam2 1department of crop physiology and ecology, hajee mohammad danesh science and technology university (hstu), dinajpur, bangladesh. 2division of plant breeding, bangladesh wheat and maize research institute(bwmri),dinajpur, bangladesh. corresponding e-mail: minarbari07@gmail.com (received: 18 march, 2020, accepted: 19 august, 2020) keywords: rice varieties, fertilization, soil health, yield, yield contributing characters abstract an experiment was carried out at the research field of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur from july to november 2018. the study evaluated the effects of poultry litter based composts on morpho-physiological, yield and yield contributing characters of transplanted aman rice (var.binadhan-7, brri dhan56, brri dhan66) and soil fertility. the experiment was laid out in a two factorial complete randomized design (crd) with three replications. factor a included three varieties (binadhan-7: v1, brri dhan56: v2, and brri dhan66: v3) and factor b comprised of three fertilization levels viz. control (inorganic)-f1, poultry litter based compost 20 ton ha-1: f2, and 30 ton ha -1: f3. the performances of plant growth parameters such as plant height, tiller number, leaf number, leaf area, spad value, as well as yield and yield contributing parameters, and soil chemical properties were measured. varieties and fertilizer levels significantly influenced most of the morphophysiological traits and yield and yield contributing characters. the tallest plant was recorded from v2 variety (brri dhan56). the highest leaf number hill -1 (80.89 at 30 dat) was recorded from v3 (brri dhan66). the highest number of tiller was produced by the interaction of compost f2 (20 t ha -1) with v1 (binadhan-7). the highest effective tiller number (13.67) hill-1wasrecorded from f2 (compost 20 t ha -1) with f1 (binadhan-7) at maturity. the longest panicle (24.16 cm) was found in f1v1 (inorganic with binadhan-7) treatment. the highest 1000-grain weight (23.57 g) was recorded from f3v3 treatment (compost-30 t ha -1 with brri dhan66). the maximum harvest index was recorded from f1 (inorganic) with brri dhan66. soil fertility status increased with higher dose poultry litter based compost (30 t ha-1). introduction rice (oryza sativa l.) is the principal food crop in bangladesh, and about 74.85% of the total arable lands are used for rice (aus, aman and boro) cultivation (bbs, 2018). rice plays a dominant role in bangladesh agriculture sinceit covers 74.85 percent of the total cropped area (bbs, 2018). the yield of rice is low (3.072 t ha-1) in bangladesh compared to other ricegrowing countries (bbs, 2018). it has already been reported that decreasing organic matter in farm soils has caused significant yield reductions (shelly et al., 2016). almost 85% of the population of bangladesh lives in rural areas having the main occupation of farming. the 14 chowdhury et al. government of bangladesh has given the highest priority to increase food availability in the country (saha et al., 2009). one of the methods to reach this goal regarding increasing the food sufficiency is the reduction of the yield gap of the food grain per unit area. a modern variety of transplant aman can be planted intensively to augment income and welfare for low-income farmers (sarker et al., 2013). the depleted soil fertility is a major constraint to higher crop production in bangladesh. rice-rice is the most common cropping system in bangladesh. continuous practicing of this highly exhaustive cropping sequence in most irrigated fertile lands resulted in the decline of soil physio-chemical conditions in general, particularly soil organic matter (som) content (liza et al., 2014 and hossaen et al., 2011). it is known that inorganic fertilizers supply only nutrients in the soil, but organic manure supplies nutrients as well as improves soil quality. the long term impact of chemical fertilizers on soils and the environment is harmful (tilahun et al., 2013, diacono and montemurro, 2010 and golabi et al., 2007). the use of unbalanced nutrients in the soils may be harmful in the long run causing soils an unproductive one. indeed, sustainable production of crops cannot be maintained by using only chemical fertilizers, and similarly, it is not possible to obtain higher crop yield by using organic manure alone (saha, 2014 and bair, 1990). a judicious combination of organic and inorganic sources of nutrients is necessary for sustainable agriculture that can ensure food production with high quality (islam et al., 2014 and nambiar, 1991). integrated use of organic manure and chemical fertilizers would be quite promising not only in providing high stability in production but also in maintaining better soil fertility (chowdhury et al., 2020 and alam, 2017). poultry manure is another good source of nutrients in the soil. meelu and singh (1991) showed that 4 t ha-1 poultry manure along with 60 kg n ha-1 as urea produce grain yield of crop similar to that with 120 kg nha-1 as urea alone. but direct application of poultry manure has harmful effects on soil health (urra et al., 2019). that’s why it needs to be composted. poultry litter based compost can supply a substantial amount of plant nutrients and, therefore, can contribute to crop yields (chowdhury et al., 2013, kobra, 2016; najafi and abbasi, 2013). therefore, it is necessary to use fertilizer and manure in an integrated way to obtain sustainable crop yield without declining soil fertility. applications of both chemical and organic fertilizers need to be applied for the improvement of soil physical properties and supply of essential plant nutrients for higher yield. the present investigation was, therefore, undertaken to develop a suitable integrated dose of poultry litter based compost for rice (var.binadhan-7, brri dhan56, brri dhan66) and to observe the effects of different levels of inorganic fertilizers and poultry litter based compost on the yield and yield components of rice (var. binadhan-7, brri dhan56, brri dhan66) as well as soil fertility. materials and methods the experiment was conducted to find out the effect of fertilizer and manure on the yield of t. aman rice. it was conducted during the period from july to november 2018 in the wet season. the location of the site is crop physiology and ecology research field, hajee mohammad danesh science and technology university (hstu), dinajpur. the experiment was laid out in a two factorial complete randomized design (crd) with three replications. factor-a: three varieties were v1 = binadhan-7, v2 = brri dhan56, v3= brri dhan66 and factor-b: three fertilization treatment were: f1 = control (inorganic), f2 = compost 20 t ha -1, f 3 = compost 30 t ha -1 . the soil was collected from the arable land of crop physiology and ecology research field, hajee mohammad danesh science and technology university (hstu), dinajpur from a depth performance of poultry litter based compost on yield of t. aman rice 15 of l5 cm. the collected soil was sundried for a week, and the weeds were removed. fifteenkilogram soil was taken into each pot. thus the pots were ready for planting. the pots were placed in the selected space of the research field of crop physiology and ecology, hstu, dinajpur in 18 rows and 3 columns. the row to row and column to column distance was maintained properly. the amounts of n, p, k, s and zn fertilizers required per pot (control) were calculated as per the weight of soil. the full amount of tsp, mop, gypsum and zinc sulphate was applied as basal dose before transplanting of rice seedlings for f1 fertilization (control). poultry litter based composts were applied150 g pot-1 for f2 fertilization and 225 g pot -1 for f3 fertilization. the compost used in this research was made by kobra (2016). composting material was poultry manure, sawdust, rice husk and ash. chemical compositions of poultry litter based compost were n-1.6%, p-1.21%, and k-0.35% (kobra, 2016). the seedlings of rice (var. binadhan-7, brri dhan56and brri dhan66) were collected from badc, dinajpur. during seedling growing, no fertilizers were used. proper water and pest management practices were followed whenever required. forty days old seedlings of rice were carefully transplanted on july 23, 2018in well puddle pots. three seedlings were sown in each pot. intercultural operations were done to ensure the normal growth of the crop. plant protection measures were followed as and when necessary. soil n, p, k, s, ph, organic matter and organic carbon were measured. soil analysis was done following standard methods at srdi, nashipur, dinajpur. the data obtained for different parameters were statistically analyzed to find out the significant difference between chemical fertilizers and poultry litter based composts on the yield of transplant aman rice. the mean values of all the characters were calculated and analysis of variance was performed by mstat-c statistical software. the significance of the differences among the treatment means was estimated by duncan’s multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). results and discussion the experiment was conducted to find out the effect of fertilizer and manure on the yield of t. aman rice in different soil. the results are presented and discussed in the tables and possible interpretations are given under the following headings. plant height the effects of poultry litter based composts on plant height at different days after transplanting (dat) were statistically significant (table 1). results showed that plant height increased with various doses of compost. the tallest plant was recorded in brri dhan56 at 30 dat where the lengths were 74.22, 99.11, 101.3, 101.6 and 103.6 cm at maximum vegetative, booting, anthesis, and maturity stages, respectively. the shortest plant was recorded from binadhan-7 where the lengths of the plants were 63.78, 78.78, 85.78, 88.78 and 91.22 cm at 30 dat, maximum vegetative, booting, anthesis and maturity stages respectively. the tallest plant was recorded from f1fertilization (inorganic) (72.78 cm at 30 dat). the tallest plant was recorded from f3fertilization (compost-30t ha -1) (92.22 and 101.1 cm at vegetative and booting stages, respectively. and the tallest plant was recorded from f1fertilization (inorganic) (95.44 and 98.11 cm at anthesis and maturity stages, respectively. the shortest plants were recorded from f2fertilization (compost-20 t ha -1) (64.67, 85.11, 88.00, 94 and 96 cm at 30 dat, maximum vegetative, booting, anthesis and maturity stages, respectively). plant height was significantly affected by the interaction between fertilization and different varieties (table 1). results indicated that the tallest plants (84.67, 104.7, 108, 105.3 and 107.3 cm at 30 dat, maximum 16 chowdhury et al. vegetative, booting, anthesis and maturity stages, respectively were found in f2 (compost 20 t ha-1) fertilization with variety v1 (binadhan-7), and the shortest plants (61.33cm at 30 dat) from f3v2. inorganic fertilizer may help in initial plant height enhancement due to quick nutrient availability, but later on, similar results were found by the application of other treatments (poultry litter based composts). a similar result was also reported by hosaain et al. (2010) and buri et al. (2006). number of leaves hill-1 the effects of poultry litter based composts on leaf number hill-1 at different days after transplanting (dat) were statistically insignificant (table 2). results showed that leaf number hill1 increased with minimum different doses of compost. the highest leaf number hill-1 (80.89 at 30 dat) was recorded from v3. the highest leaf number hill -1 at vegetative and booting were recorded from v2 (brri dhan56) and the highest leaf number hill -1 at anthesis was recorded from v1 (binadhan-7). the lowest leaf number hill -1was recorded from v3 (54.56) at anthesis. the different fertilization doses influenced the leaf number hill-1. the highest number of leaves hill-1 was found from f3 and the lowest one was for f2 at anthesis. leaf number hill -1 was insignificant. number of tiller hill-1 the effects of poultry litter based composts on tiller hill-1at different days after transplanting (dat) were statistically significant (table 3). results showed that the number of tillers hill-1 increased with various doses of compost. the highest number of tiller number hill-1 was recorded from v2 variety (brri dhan56) (15.33, 14.89, 15.56, 13.11 and 14.11 at 30 dat, maximum vegetative, booting, anthesis and maturity stages, respectively). the shortest plant was recorded from v1 variety (binadhan-7) (13, 13.44, 14.89, 12.78 and 13.44 at 30 dat, maximum vegetative, booting, anthesis and maturity stages, respectively). the highest tillers number hill-1 were recorded from f1 (inorganic) (15.33, 15.33, 13.67 and 15.44 at 30dat, maximum vegetative, anthesis and maturity stages respectively). the highest tillers number hill-1were recorded from f3 (compost-30 t ha -1) (16.22 at booting stage). the lowest tillers number hill1were recorded from f2 (compost-20 t ha -1) (12.56, 11.89 and 13.89 at 30 dat, vegetative, booting stages, respectively). the lowest tiller number hill-1 was recorded from f3 (compost-30 t ha-1) (11.78 and 12.33 at anthesis and maturity stages, respectably). table 1. effect of fertilization on plant height of different rice varieties at different stages treatments plant height (cm) varieties 30 dat vegetative booting anthesis maturity v1=binadhan-7 63.78b 78.78b 85.78b 88.78b 91.22b v2=brri dhan56 74.22a 99.11a 101.3a 101.6a 103.6a v3=brri dhan66 65.11b 90.67a 98.56a 94.22ab 97ab level of significance ** ** * ** ** fertilization f1=inorganic 72.78a 91.22 96.56ab 95.44 98.11 f2=compost 20 tha -1 64.67b 85.11 88.00b 94.00 96.00 f3=compost 30 tha -1 65.67b 92.22 101.10a 95.11 97.67 level of significance ** ns * ns ns interaction v1 64.00bc 82.33bc 90.67ab 92.33cd 96.33bc performance of poultry litter based compost on yield of t. aman rice 17 treatments plant height (cm) f1 v2 62.67bc 72.00c 71.00b 86.33d 88.ood v3 64.67bc 82.00bc 95.67a 87.67d 89.33cd f2 v1 84.67a 104.7a 108.00a 105.3a 107.30a v2 70.00b 90.67ab 93.67a 101.7ab 103.7ab v3 68.00bc 102.0a 102.30a 97.67abc 99.67ab f3 v1 69.67b 86.67b 91ab 88.67d 90.67cd v2 61.33c 92.67ab 99.33a 94.00b-d 96.33bc v3 64.33bc 92.67ab 105.30a 100.00a-c 104.00ab level of significance ** * * ** ** cv (%) 5.00 7.99 11.10 5.82 5.49 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p≤ 5% level of probability. ns indicates insignificant, *indicates significant at 5% level of probability **indicates significant at 1% level of probability table 2. effect of fertilization on leaf number of different rice varieties at different stages treatments leaf number varieties 30 dat vegetative booting anthesis v1=binadhan-7 67.56 85.56ab 90.11 54.56 v2=brri dhan56 69.56 94.33a 93.11 53.89 v3=brri dhan66 80.89 75.56b 91.56 51.67 level of significance ns * ns ns fertilization f1=inorganic 77.11 90.22ab 95.56a 57.00 f2=compost 20 tha -1 63.56 70.11b 81.78a 49.67 f3=compost 30 tha -1 77.33 95.11a 97.44a 53.44 level of significance ns * ns ns interaction f1 v1 80.00 98.00 90.67 58.67 v2 54.67 68.33 89.33 54.67 v3 68.00 90.33 90.33 50.33 f2 v1 77.67 104.0 100.7 58.33 v2 59.00 76.67 78.67 45.67 v3 72.00 102.3 100.00 57.67 f3 v1 73.67 68.67 95.33 54.00 v2 77.00 65.33 77.33 48.67 v3 92.00 92.67 102.00 52.33 level of significance ns ns ns ns cv (%) 28.98 23.32 17.94 15.78 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability 18 chowdhury et al. number of effective tillers hill-1 the effects of varieties on the number of effective tillers hill-1 at different days after transplanting (dat) were statistically significant (figure 1). results showed that the number of effective tiller hill-1 increased with various doses of poultry-based compost. the highest number of effective tiller hill-1 was recorded from v2 (brri dhan56) (11.44 and 12.33 at anthesis and maturity stage, respectively). the lowest number of effective tillers hill-1 was recorded from v3 (brri dhan66) (10.89 and 11.56 at anthesis and maturity stage, respectively). the number of effective tillers hill-1 was influenced by different fertilization presented in fig. 2. it was observed that f1 (inorganic) produced the highest number of effective tillers hill-1 (11.89 at anthesis stage), and f2 (compost-20 t ha-1) showed the lowest result (12.33 at maturity stage). the number of effective tillers hill-1 was significantly affected by the interaction between varieties and fertilization (fig. 3). results indicated that the highest number of effective tillers hill-1 (12.67, 13.67) was found in the combination of v1f2 (binadhan-7 with compost-20 t ha -1). nitrogen availability may play an important role in the tiller generation. inorganic fertilizer is a good source of available nitrogen with flooding irrigation as per islam et al. (2014), shaha (2014) and hossain (2010). alam et al. (2012) also stated similar findings. table 3. effect of fertilization on tiller number of different rice varieties at different stages treatments tiller number varieties 30dat vegetative booting anthesis maturity v1=binadhan-7 13.00 13.44 14.89 12.78 13.44 v2=brri dhan56 15.33 14.89 15.56 13.11 14.11 v3=brri dhan66 13.67 13.22 15.56 12.11 12.78 level of significance ns ns ns ns ns fertilization f1=inorganic 15.33 15.33 15.89 13.67 15.44 f2=compost 20 tha -1 12.56 11.89 13.89 12.56 12.56 f3=compost 30 tha -1 14.11 14.33 16.22 11.78 12.33 level of significance ns * ns ns ** interaction f1 v1 17.00a 16.33 14.67 14.00 15.33ab v2 8.33b 11.67 15.00 13.00 13.33abc v3 13.67ab 12.33 15.00 11.33 11.67c f2 v1 16.67a 17.33 17.00 14.00 16a v2 15.67a 12.00 13.00 13.00 12.67bc v3 13.67ab 15.33 16.67 12.33 13.67abc f3 v1 12.33ab 12.33 16.00 13.00 15ab v2 13.67ab 12.00 13.67 11.67 11.67c v3 15.00a 15.33 17.00 11.67 11.67c level of significance * ns ns ns ** cv (%) 18.49 21.70 20.16 17.52 15.75 in a column, means followed by different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability performance of poultry litter based compost on yield of t. aman rice 19 fig. 1. effect of different varieties on effective tiller/hill at anthesis and maturity stages fig. 2. effect of different fertilization on effective tiller/hill in rice at anthesis and maturity stages fig.3. interaction effect between different varieties and different fertilization on effective tiller/hill in rice at anthesis and maturity stages 11.67 11.33 12.33 11.44 11.56 10.89 0 2 4 6 8 10 12 14 maturity anthesis n u m b e r o f e ff e c ti v e t il le r varieties v1=binadhan7 v2=brri dhan57 v3=brri dhan66 11.89 13.44 a 11 11.22 ab 10.78 10.89 b 0 2 4 6 8 10 12 14 16 anthesis maturity n u m b e r o f e ff e c ti v e t il le r fertilization f1= inorganic f2= 20 t/ha f3= 30 t/ha 1 1 .6 7 1 3 .3 3 1 1 .6 7 1 1 1 0 .6 7 1 0 .6 7 1 2 .6 7 1 3 .6 7 1 0 .6 7 1 1 .3 3 1 1 1 2 1 1 .3 3 1 3 .3 3 1 0 .6 7 1 1 .3 3 1 0 .6 7 1 0 0 2 4 6 8 10 12 14 16 anthesis maturity n u m b e r o f e ff e c ti v e t il le r variety and fertilization level f1v1 f1v2 f1v3 f2v1 f2v2 f2v3 f3v1 f3v2 f3v3 20 chowdhury et al. stem dry weight hill-1 stem dry weight per plant was affected by the interaction between variety and fertilization presented in table 4. at the maximum vegetative stage, the highest stem dry weight per plant (9.93g) was obtained in v3f2 (brri dhan66 with compost-20 t ha -1), and the lowest stem dry weight plant-1 (6.2 g) was obtained in v3f1 (brri dhan66 with inorganic). at the booting stage, the highest stem dry weight plant-1(15.29 g) was obtained in v3f3 (brri dhan66 with compost30 t ha-1) and the lowest stem dry weight plant-1(10.30 g) was obtained in v2f2 (brri dhan56 with compost-20 t ha-1). at the anthesis stage, the highest stem dry weight plant-1(42.14g) was obtained in v1f2 (binadhan-7 with compost-20 t ha -1), which was statistically similar in v1f1 (binadhan-7 with inorganic) (42.02 g), and the lowest stem dry weight plant-1(27.65 g) was recorded from v2f3 (brri dhan56 with compost-30 t ha -1). leaf dry weight hill-1 leaf dry weight plant-1 was affected by the interaction between variety and fertilization presented in table 4. at the vegetative stage, the highest leaf dry weight plant-1 (8.26 g) was obtained in v3f2 (brri dhan66 with compost-20 t ha -1) and the lowest leaf dry weight plant-1 (5.50 g) was obtained in v1f3 (binadhan-7 with compost-30 t ha -1). at the booting stage, the highest leaf dry weight plant-1 (9.86 g) was obtained in v3f3 (brri dhan66 with compost-30 t ha -1) and the lowest leaf dry weight plant-1 (6.65 g) was obtained in v2f3 (brri dhan56 with compost-30 t ha-1). table 4. effect of fertilization on stem dry weight and leaf dry weight of different ricevarieties at different stages treatments stem dry weight (g) leaf dry weight (g) varieties vegetative booting anthesis vegetative booting anthesis v1=binadhan-7 7.44 11.93 37.28 6.91 8.18 4.66 v2=brri dhan56 9.24 13.17 37.29 7.52 8.18 4.52 v3=brri dhan66 7.38 13.29 34.87 6.22 8.23 4.33 level of significance ns ns ns ns ns ns fertilization f1=inorganic 9.00 13.18 41.37a 7.28 8.44 4.91 f2=compost 20 tha -1 6.62 11.47 30.57b 5.73 7.17 4.13 f3=compost 30 tha -1 8.44 13.74 37.50a 7.64 8.98 4.47 level of significance ns ns ** ns ns ns interaction f1 v1 9.60 12.27 42.02a 8.12 8.23 4.81 v2 6.52 12.33 33.95a-c 5.63 7.80 4.91 v3 6.20 11.20 35.87a-c 7.00 8.51 4.27 f2 v1 10.83 14.47 42.14a 8.23 8.90 5.26 v2 6.96 10.30 30.09bc 6.06 7.08 3.70 v3 9.93 14.73 39.63a 8.26 8.57 4.61 f3 v1 6.56 12.80 39.96a 5.50 8.19 4.66 v2 6.40 11.77 27.65c 5.50 6.65 3.80 v3 9.19 15.29 37ab 7.66 9.86 4.52 level of significance ns ns ** ns ns ns cv (%) 23.83 23.35 16.31 28.18 22.20 19.13 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability performance of poultry litter based compost on yield of t. aman rice 21 at the anthesis stage, the highest leaf dry weight plant-1 (5.26 g) was obtained in v1f2 (binadhan-7 with compost-20 t ha-1), and the lowest leaf dry weight plant-1 (3.7 g) was recorded from v2f2 (brri dhan56 with compost-20 t ha -1). root dry weight hill-1 root dry weight plant-1was affected by the interaction between variety and fertilization presented in table 5. at the vegetative stage, the highest root dry weight plant-1(4.3g) was obtained in v3f2 (brri dhan66 with compost-20 t ha -1), and the lowest root dry weight plant-1(2.18g) was obtained in v2f2 (brri dhan56 with compost-20 t ha -1). at the booting stage, the highest root dry weight plant-1(3.86g) was obtained in v2f1 (brri dhan56 with inorganic), and the lowest root dry weight plant-1(2.65g) was obtained in v3f2 (brri dhan66 with compost-20 t ha -1).at the anthesis stage, the highest root dry weight plant-1(3.01g) was obtained in v1f1binadhan-7 with inorganic), and the lowest root dry plant-1 (2.2g) was recorded from v2f3 (brri dhan56 with compost-30 t ha-1). leaf area leaf area evaluated for different varieties and fertilization is presented in table 5. leaf area was found with almost similar in each treatment. the maximum leaf area was recorded from v2 (brri dhan56) (5588 cm2 and 5229 cm2 at vegetative and booting stages, respectively) and the maximum leaf area was recorded from v1 (binadhan-7) (3126 cm 2 and 3159 cm2 at anthesis and maturity stages, respectively). table 5. effect of fertilization on root dry weight and leaf area of different rice varieties at different stages treatments root dry weight (g) leaf area (cm2) varieties vegetative booting anthesis vegetative booting anthesis maturity v1=binadhan-7 2.79 3.05 2.67 5028 5151 3126 3159 v2=brri dhan56 3.29 3.29 2.61 5588 5229 2805 3119 v3=brri dhan66 2.92 3.35 2.46 4500 5210 2905 3116 level of significance ns ns ns ns ns ns ns fertilization f1=inorganic 3.08 3.13 2.78 5305 5352 3096 3156 f2=compost 20 tha -1 2.59 2.92 2.32 4227 4628 2675 3058 f3=compost 30 tha -1 3.34 3.65 2.64 5585 5610 3065 3181 level of significance ns ns ns ns ns ns ns interaction f1 v1 2.93 2.82 3.01 5755 5169 3297a 2924 v2 2.66 3.86 2.52 4163 5135 3082ab 3458 v3 2.80 2.89 2.48 5167 5150 2997ab 3096 f2 v1 3.40 3.45 2.76 6095 5557 2989ab 3356 v2 2.18 3.58 2.25 4667 4356 2338b 2634 v3 4.30 2.65 2.84 6003 5774 3089ab 3367 f3 v1 2.90 3.65 2.58 4065 5331 3003ab 3188 v2 2.93 2.98 2.20 3850 4392 2603ab 3080 v3 2.93 3.22 2.60 5584 5908 3109ab 3081 level of significance ns ns ns ns ns * ns cv (%) 21.69 21.44 22.90 23.83 18.06 18.80 17.18 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability 22 chowdhury et al. the maximum leaf area was recorded from f3 (compost-30 t ha -1) (5585 cm2, 5610 cm2 and 3181 at vegetative, booting and maturity stages, respectively), and the maximum leaf area was recorded from f1 (inorganic) (3096 cm 2 at anthesis stage). at the vegetative stage, the highest leaf area (6095 cm2) was obtained in v3f2 (brri 66 with compost-20 t ha -1) and the lowest leaf area (3850 cm2) was obtained in v2f3 (brri dhan56 with compost-30 t ha -1). at the booting stage, the highest leaf area (5908 cm2) was obtained in v3f3 (brri dhan66 with compost-30 t ha-1), and the lowest leaf area (4356 cm2) was obtained in v2f2 (brri dhan56 with compost-20 t ha-1). at the anthesis stage, the highest leaf area (3109 cm2) was obtained in v3f3 (brri dhan66 with compost-30 t ha-1) and the lowest leaf area (2338 cm2) was obtained in v2f2 (brri dhan56 with compost-20 ton ha-1). at the maturity stage, the highest leaf area (3458 cm2) was obtained in v2f1 (brri 56 with inorganic), and the lowest leaf area (2634 cm 2) was obtained in v2f2 (brri dhan56 with compost-20 t ha -1). spad value spad value was significantly influenced by poultry litter based composts, but the spad value was not significantly influenced in the case of varieties (table 6). result revealed that spad value was increased with the use of composts. the highest spad value (48.74) was recorded from f3and the lowest spad value (44.77) from f2 at vegetative stages in other stages spad value was not significant. the interaction effect of fertilization and different varieties was significantly influenced by spad value at vegetative and booting stages. table 6. effect of fertilization on spad value of different rice varieties at different stages treatments stages varieties vegetative booting anthesis v1=binadhan-7 47.44 40.77 46.76 v2=brri dhan56 44.57 41.16 45.62 v3=brri dhan66 49.33 40.71 46.77 level of significance ns ns ns fertilization f1=inorganic 47.83ab 41.48 45.53 f2=compost 20 tha -1 44.77b 39.49 46.73 f3=compost 30 tha -1 48.74a 41.67 46.88 level of significance * ns ns interaction f1 v1 47.57ab 42.13ab 46.60 v2 44.8b 39.73ab 46.17 v3 49.97ab 40.43ab 47.50 f2 v1 46.37ab 39.57ab 43.97 v2 43.27b 40.30ab 46.07 v3 44.07b 43.60a 46.83 f3 v1 49.57ab 42.73ab 46.03 v2 46.23ab 38.43b 47.97 v3 52.20a 40.97ab 46.30 level of significance * * ns cv (%) 7.48 5.98 5.38 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability performance of poultry litter based compost on yield of t. aman rice 23 the highest spad value (52.20) at the vegetative stage was recorded from f3v3 (compost -30 t ha-1 with brri dhan66), and the lowest spad value (43.27) was recorded from f2v2. the highest spad value (43.60) at the booting stage was recorded from f2v3. the lowest spad value (38.43) was recorded from f3v2 at the booting stage. spad value was significantly influenced by poultry litter based composts but the spad value insignificant in the case of varieties (table 8). result revealed that spad value was increased with the use of composts. the highest spad value (48.74) was recorded from f3 and the lowest spad value (44.77) from f2 at the vegetative stages, whereas in other stages spad value was not significant. the interaction effect of fertilization and different varieties was significantly influenced by spad value at vegetative and booting stages. the highest spad value (52.20) at the vegetative stage was recorded from f3v3whreas the lowest spad value (43.27) was recorded from f2v2 at the vegetative stage. the highest spad value (43.60) at the booting stage was recorded from f2v3 and the lowest spad value (38.43) from f3v2 at the booting stage. zubaer et al. (2007) and chowdhury et al. (2020) found a similar result at drought conditions that compost and nutrients increased chlorophyll contents in a crop plant. panicle length panicle length was not significantly influenced by poultry litter based composts but significantly influenced by different rice varieties (table 7). the longest panicle length (22.9 cm) was produced by v1 (binadhan-7), and the shortest panicle length (20.48 cm) produced by v3 (var. brri dhan66). panicle length was not significantly influenced by poultry litter based composts (table 9). interaction between fertilizer and different rice varieties significantly influenced the panicle length. the longest panicle (24.16cm) found in f1v1 (inorganic with binadhan-7) treatment and the shortest one (19.83cm) found in f3v3 (compost-30 t ha -1 with brri dhan66). sarker et al. (2013) and haque (2013) was found similar results of increased panicle length due to the application of manure on rice plants. 1000-grain weight production of rice yield also depends on 1000-grain weight, which was significantly influenced by poultry litter based composts, but the 1000-grain weight was not significantly influenced by varieties (table 7). results revealed that the highest 1000-grain weight (22.23g) was recorded from f3and the lowest 1000-grain weight (19.66 g) was recorded from f2. this result was in agreement with the reports of aziz (2008). the interaction effect of fertilizer and different varieties significantly influenced the 1000-grain weight. the highest 1000-grain weight (23.57 g) was recorded from f3v3 treatment and the lowest 1000-grain weight (19.27 g) was recorded from f1v2 (inorganic with brri dhan56). grain yield grain yield was significantly influenced by poultry litter based composts, but the grain yield (g pot-1) was not significantly influenced in the case of varieties (table 7). result revealed that grain yield was increased with the use of composts. the highest grain yield (23.61 g pot-1) was recorded from f1 (inorganic). the lowest grain yield (14.32 g pot -1) was recorded from f2 (compost-2 t ha-1). the interaction effect of fertilizer and different varieties was significantly influenced by grain yield. the highest grain yield (24.58 g pot-1) was recorded from f3v1 (compost-30 t ha-1 with binadhan-7). the lowest grain yield (11.98 g pot-1) was recorded from f2v2 (compost -20 t ha -1 with brri dhan56).islam et al. (2013) and najafi and abbasi (2013) also found a similar result in rice production. saleque et al. (2004) reported that the application of compost increased the yield of rice. 24 chowdhury et al. straw yield the straw yield was significantly influenced by poultry litter based composts (table 7). result revealed that straw yield was increased with the use of composts. but the straw yield was not significantly influenced in varieties. the highest straw yield (18.19 g) was recorded from f1 (inorganic). the lowest straw yield (14.76 g) was recorded from f3. the combined effect of compost and different varieties significantly influenced the straw yield. the highest straw yield (18.6 g) was recorded from f2v1 (compost 20 t ha -1 with binadhan-7). the lowest straw yield (13.5 g) was recorded from f3v3 (compost-30 t ha -1 with brri dhan66) treatment. harvest index as a useful index of measuring the plant biomass converted into fruitful economic yield, the harvest index was significantly influenced by poultry litter based composts (table 7). the harvest index was not significantly influenced by varieties. results revealed that the harvest index was increased with the use of different composts treatment. the highest harvest index (58.2%) was recorded from f3 (compost 30t ha -1). the lowest harvest index (47.89%) was recorded from f2 (compost-20 t ha-1). the combined effect of poultry litter based composts and different varieties significantly influenced in harvest index. the highest harvest index (62.78%) was recorded from f1v3 (inorganic brri dhan66). the lowest harvest index (45.04%) was recorded from f2v2 (compost 20t ha-1× brri dhan56). table 7. effect of fertilization on yield parameters of different varieties of rice treatments yield parameters varieties panicle length (cm) grain yield g pot-1 1000 grain weight (g) straw yield (g pot-1) harvest index (%) v1=binadhan-7 22.9a 21.63 20.80 16.09 57.03 v2=brri dhan56 22.49a 17.74 20.11 16.66 50.47 v3=brri dhan66 20.48b 19.49 22.26 15.50 54.79 level of significance ** ns ns ns ns fertilization f1=inorganic 22.60 23.61a 21.28ab 18.19a 56.19a f2=compost 20 tha -1 21.85 14.32b 19.66b 15.3b 47.89b f3=compost 30 tha -1 21.42 20.92a 22.23a 14.76b 58.2a level of significance ns ** ** ** * interaction f1 v1 24.16a 24.28ab 20.9ab 18.17a 57abc v2 22.5abc 16.71bcd 19.27b 16.03abc 51.31abc v3 22.05abc 23.91ab 22.23ab 14.07bc 62.78a f2 v1 22.97ab 21.98ab 20.15ab 18.6a 53.54abc v2 22.11abc 11.98d 19.3b 14.67abc 45.04c v3 22.38abc 19.26abcd 20.89ab 16.7abc 52.82abc f3 v1 20.66bc 24.58a 22.8a 17.8ab 58.04ab v2 20.94bc 14.29cd 20.42ab 15.2abc 47.33bc v3 19.83c 19.59abc 23.57a 13.5c 59.01ab level of significance ** ** ** ** ** cv (%) 7.14 19.16 7.66 15.72 13.26 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability performance of poultry litter based compost on yield of t. aman rice 25 soil chemical properties results revealed that organic matter was increased with the use of different composts treatment (table 8). the highest organic matter (2.328%) and the highest organic carbon (1.29%) were found in the case of f3 (compost 30 t ha -1).the lowest organic matter (1.03%) and the lowest organic carbon (0.49%) were found in the case of f1 (inorganic). the change of ph value was insignificant by the application of fertilization. results revealed that n, p, k, s content of the soil was increased with the use of different composts treatment. the highest n (0.102%), p (130.0µg/g soil), k (0.449ppm/100g soil), s (62.04µg/g soil) was found in f3 (compost 30 t ha-1) treatment. the lowest n (0.0856%), p (110.0 µg/g soil), k (0.37 ppm/100g soil), s (39.92µg/g soil) was found in f1 (inorganic) treatment. a similar trend was also found by liza et al. (2014) and salaque et al. (2004) due to the application of organic manure. table 8. effect of fertilization on soil chemical properties treatments fertilization ph organic matter (%) organic carbon (%) n(%) p (µg/g soil) k (ppm/100 g soil) s (µg/g soil) f1=inorganic 6.529 1.030c 0.49b 0.0856 110.0b 0.37b 39.92c f2=compost 20 tha -1 6.650 1.912b 1.13a 0.090 126.4a 0.436a 49.24b f3=compost 30 tha -1 6.618 2.328a 1.289a 0.102 130.0a 0.449a 62.04a level of significance ns ** ** ns ** ** ** cv (%) 1.85 20.78 22.73 22.09 6.72 8.02 11.94 in a column, means followed by a different letter(s) differed significantly by duncan’s multiple range test at p ≤ 5% level of probability. ns indicates insignificant *indicates significant at 5% level of probability **indicates significant at 1% level of probability conclusion according to the present study, it could be suggested that the rice is grown with compost-30 t ha-1 along with var.binadhan-7) revealed to get the optimum yield. however, these findings need to be further investigated and evaluated in the different agro-ecological zone before the final recommendation for the farmers. references alam, m.j. 2017. amelioration of the adverse effect of drought on rice cultivation through poultry litter based compost.ms thesis, department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh. alam, m.s., m.a. baki, m.s. sultana, k.j. ali and m.s. islam.2012.effect of variety, spacing and number of seedlings per hill on the yield potentials of transplant aman rice. ijarit. 2 (12): 10-15. aziz, m.a. 2008. effect of cowdung on the growth and yield of hybrid and hyv rice.ms thesis, department of agronomy, bangladesh agricultural university, mymensingh. bbs (bangladesh bureau of statistics).2018. statistical yearbook of bangladesh. statistics division, ministry of planning, government of the people’s republic of bangladesh. dhaka. bangladesh. 26 chowdhury et al. bbs (bangladesh bureau of statistics). 2015. statistical yearbook of bangladesh. statistics division, ministry of planning, government of the people’s republic of bangladesh. dhaka, bangladesh. bair, w. 1990. characterization of the environment for sustainable agriculture in semi-arid tropics. in: proc. sustainable agriculture issue, prospective and prospects in semi-arid tropics (ed. singh, r.p.), hyderabad, india. india soc. agron. pp.90-128. buri, m.m., r.n. issaka, t. wakatsuki and e. otoo. 2006. soil organic amendments and mineral fertilizers: options for sustainable lowland rice production in the forest agro-ecology of ghana. agril. food sci. j. ghana, 3(1): 237-248. chowdhury, a.k.m.m.b., m.a. hossain, j. alam, m.a. hasan and m.z. islam. 2020. amelioration of adverse effect of drought on brri dhan28 through poultry litter based compost. the agriculturists 18(1): 42-55. chowdhury, a.k.m.m.b., c.s. akratos, d.v. vayenas and s. pavlou. 2013. olive mill waste composting: a review. int. biodeter biodegr. 85: 108-119. diacono, m. and f. montemurro. 2010. long-term effects of organic amendments on soil fertility. a review. agron. sustain. dev. 30: 401-422. golabi, m.h., m.j. denney and c. iyekar. 2007. value of composted organic wastes as an alternative to synthetic fertilizers for soil quality improvement and increased yield. compost sci. utilization, 15(4): 267-271. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. international rice research institute. john wiley and sons, new york pp.139-240. haque, a. 2013. integrated use of manures and fertilizers for maximizing the growth and yield of boro rice (cv. brri dhan28). ms thesis, department of soil science, bangladesh agricultural university, mymensingh. hossaen, m.a., a.t.m. shamsuddoha, a.k. paul, m.s.i. bhuiyan and a.s.m. zobaer.2011. efficacy of different organic manures and inorganic fertilizer on the yield and yield attributes of boro rice. the agriculturists 9(1&2): 117–125. hossain, m.i., m.n. uddin, m.s. islam, m.k. hossain and m.a.h. khan. 2010. effects of manures and fertilizer on nutrient content and uptake by brri dhan 29. j. agroforest. environ. 3(2): 65-67. islam, f., m.a. khan, a.s.m.f. bari, m.t. hosain and sabikunnaher, m. 2013. effect of fertilizer and manure on the growth, yield and grain nutrient concentration of boro rice (oryza sativa l.) under different water management practices. the agriculturists, 11: 44-51. islam, m.r., m.b. rashid, a.b. siddique and h. afroz. 2014. integrated effects of manures and fertilizers on the yield and nutrient uptake by brri dhan49. j. bangladesh agril. univ. 12(1): 67-72. kobra, u.e.z. 2016. valorization of poultry wastes by aerobic composting for the organic agriculture. ms thesis, department of crop physiology and ecology, hajee mohammad danesh science and technology university dinajpur-5200, bangladesh. liza, m.m.j., m.r. islam, m. jahiruddin, m.m. hasan, m.a. alam, s.m. shamsuzzaman and a.w. samsuri. 2014. residual effects of organic manures with different levels of chemical fertilizers on rice. life sci. j. 11(12): 6-12. meelu, o.p. and y. singh. 1991. integrated use of fertilizers and organic manure for higher returns. prog. farm. punjab agril. univ. 27: 3-4. najafi, n. and m.a. abbasi. 2013. effects of soil water conditions, sewage sludge, poultry manure and chemical fertilizers on macronutrients concentrations in rice plant. int. j. agron. plant prodn. 4(5): 1066-1077. performance of poultry litter based compost on yield of t. aman rice 27 nambiar, k.k.m. 1991. long-term fertility effects on wheat productivity. in: wheat for the nontraditional warm areas, (ed.) saunders d.a., cimmyt. pp.516-521. rejesus, r.m., m.e.m. mutuc, m. yasar, a.v. lapitan, f.g. palis and t.t.n. chi. 2012. sending vietnamese rice farmers back to school: further evidence on the impacts of farmer field schools. canadian j. agric. econ. 60(3): 407-426. saha, p.k. and m.a.m. miah. 2009. efficiency of ipns–based chemical fertilizer application in wet land rice. bangladesh j. agric. res. 34(1): 5–13. saha, u. 2014. integrated use of cowdung and inorganic fertilizer on the performance of modern varieties of transplanted aman rice. ms thesis, department of agronomy, bangladesh agricultural university, mymensingh, bangladesh. saleque, m.a., m.s. abedin, n.i. bhuiyan, s.k. zaman and g.m. panaullah. 2004. longterm effect of inorganic and organic fertilizer sources on yield and nutrient accumulation of lowland rice. field crops res. 86: 53-65. sarker, b.c., m. zahan, u.k. majumder, m.a. islam and b. roy. 2013. growth and yield potential of some local and high yielding boro rice cultivars. j. agroforest. environ. 7(1): 107-110. shelley, i.j., m. takahashi-nosaka, m. kano-nakata, m.s. haque and y. inukai. 2016. rice cultivation in bangladesh: present scenario, problems and prospects. j. intl. coop. agric. dev. 14: 20-29. tilahun, t., d. nigussie, b. wondimu and g. setegn. 2013. effect of farmyard manure and inorganic fertilizers on the growth, yield and moisture stress tolerance of rain-fed lowland rice. american j. res. comm. 1(4): 275-301. urra, j., i. alkorta and c. garbisu. 2019. potential benefits and risks for soil health derived from the use of organic amendments in agriculture. agron. 9(9): 542-552. zubaer, m.a., a.k.m.m.b. chowdhury, m.z. islam, t. ahmed and m.a. hasan. 2007. effects of water stress on growth and yield attributes of aman rice genotypes. intl. j. sust. crop prodn. 2(6): 25-30. bangladesh agron. j. 2020, 23(2): 35-43 nitrogen fertilization on growth and yield response of oat (avena sativa l.) m.m. islam 1 , a.a. mamun 1 *, s.k. ghosh 1 and d. mondal 1 1 agrotechnology discipline, khulna university, khulna-9208, bangladesh corresponding e-mail: mamungpbat@ku.ac.bd (received: 24 september, 2020, accepted: 04 october, 2020) keywords: oat, n fertilization, growth, productivity abstract nitrogen is one of the main inputs of oat cultivation and its efficient management is a basic for harvesting the maximum potentiality of the crop. an investigation was conducted at field laboratory of agrotechnology discipline, khulna university, bangladesh to find out the effect of nitrogen fertilizer on growth, yield and yield contributing characters of oat during 2017-2018. the experiment was designed in randomized complete block with seven n rates (0, 30, 45, 60, 75, 90 and 105 kg ha -1 ) in triplicate run. application of n nitrogen significantly increased the growth and yield of oat. the results showed that 105 kg ha -1 n was supreme in all growth parameters and straw yield but 90 kg ha -1 n was better for main yield parameters and grain yield. the maximum plant height (101.27 cm), leaf number (11.90), tillers plant -1 (9.93), plant density (41.33 m -2 ) and straw yield (4.70 tha -1 ) were recorded with 105 kg ha -1 n application, whereas the highest grain yield (1.76 t ha -1 ) was found with 90 kg ha -1 n. from the results of the present research, it may be concluded that application of 90 kg n ha -1 could be used for oat production in soils of aez 13, bangladesh. introduction in meeting up human nutrition, the cereals are on the first place in bangladesh and also in the world. among the cereals, the oat (avena sativa l.) is a healthy and useful addition to human diet and animal feed (barut, 2003; peterson et al., 2005). oats are cultivated for the grain, as source of protein, for hay, as winter cover, and are used as a pasture crop in the growing or milk stage during rabi season. it is adapted to a wide range of soil types, altitude and rainfall conditions. it can tolerate waterlogged conditions better than most of other cereals (mengistu, 1997). foods that are prepared with oat include oats bran, oats meal, oats flour and oats flakes, which are mainly consumed as breakfast cereals. oat straw is used as fodder, but mostly for bedding purposes because of its excellent absorbent qualities. other food products processed from oat are infant foods, muesli, granola bars, breads and biscuits or cookies. in brewing, oats are mainly used as an ingredient to improve the pleasant flavor properties of the final product. additionally, new processes have been recently developed to manufacture non-dairy functional products using oats (duke, 1983). oats has traditionally been considered as a low input crop and can be grown on soil with lower fertility. however, it grows poorly without the addition of nutrients. for higher yield, nutrient management is now considered as a great factor when growing oats. the unsatisfactory yield of oats in bangladesh is mainly ascribed to low soil fertility, inadequate manuring and cultural practices. the agricultural lands of bangladesh are characterized with low amounts of organic matter having poor ability to retain nutrients. continuous loss of nutrients from the soil without replacement makes the soil deficient in nutrients or the nutrients reduced to marginal level. the continued depletion of nutrients, particularly n from soil will eventually reduce soil n supply and decrease the productivity and quality of the produces. 36 islam et al. high yields of a crop are the result of ensuring environmental, technological, management, capital, and inputs timely. proper and optimum application of fertilizers not only increases the yield but also favorably affects the quality of the produce (may et al., 2004). nitrogen is largely responsible for setting up the yield potential of the crop. the use of n fertilizer is a major factor for the profitable production of most of the crops. the use of optimal n rates may allow the crop to give higher yield by lixiviating it into available form during crop development. apart from the other roles played by nitrogen, it is a major constituent of protein and chlorophyll of green plant. however, higher dose of nitrogen cause lodging of crop. nitrogen deficient plants are stunted, have fewer tillers, smaller heads and finally grain yield is reduced primarily through a reduction in kernels per head and head density. the n for plant growth is supplied from both the soil and from the application of n fertilizer. where the available n is inadequate for optimum yield and quality, n fertilizer is required to supply to optimize the production. soil type, cropping history, yield potential and the season are important factors to consider in n management decisions (https://www.agric.wa.gov.au). the main reason for low acreage of oats is that this crop is grown with little care for optimum yield. as a result average yields and gross returns frequently have been low. many reports of high yields have been made by farmers and researchers, showing that high yields with excellent quality can be attained. numerous experiments have shown that oats will respond to fertilizer when soil fertility is limiting (jackson et al., 1994; koul, 1997; omer, 1998 and gasim, 2001). however, several factors are responsible for less than maximum economic return and among them a recommended rate of n fertilizer is an important factor in determining the potential yield. nitrogen fertilization is still so complex and is worth to research closely as its effects are very variable due to environmental factors. if an optimum n fertilizer dose could be marked, then the most profitable rates of n fertilization could be recommended to the oats producer. in many cases, the producer is also interested to get high straw yield of oats for feeding their animals. however, for the harvest of the increased grain and straw yield it is necessary to apply optimum quantity of n fertilizer. considering the importance of n on the productivity of oats, an investigation was carried out to find out the response of yield and yield components of oat to different doses of n fertilizer. materials and methods site and soil description: the study to investigate the effect of varying doses of nitrogenous fertilizer on growth and yield of oat was executed at the professor dr. purnendu gain field laboratory of agrotechnology discipline, khulna university, khulna during rabi season of 2017-18. the area was located in the agro-ecological zone of ganges tidal floodplain (aez 13). the experimental site was situated by latitude 22°79′88″ e, longitude 89°53′44″ n and elevation of 18 m above mean sea level with sub-tropical climate. before sowing the crop, the soil of the experimental field was analyzed in the laboratory for their physico-chemical properties. soil was well drained, non-saline and non-sodic clay loam type with ph 6.8, total n 0.060%, available p2o5 38.0 kg ha -1 and available k2o 265.0 kg ha -1 . treatments and experimental design: the experiment was arranged in randomized complete block design (rcbd) with seven treatments (table 1) each replicated thrice. a net plot size of 3.0 m  2.0 m was maintained for each treatment. a distance of block to block 0.5 m and that of plot to plot 0.25 m was maintained. recommended dose of fertilizers (eagri, 2012), except n, was applied. crop husbandry: seeds of an indian oat cultivar kent, collected from central cattle breeding and dairy farm (ccbdf), dhaka, was used as the planting material in this experiment. seeds were treated with vitavax-200 at the rate of 3 g kg -1 seed for 24 hours, was sown along the open furrow spaced 25 cm apart at 4-5 cm depth at a seed rate of 60 kg ha -1 . full dose of organic manure (cow dung) was added three weeks before sowing. recommended full quantity of phosphorus and potash and half dose of nitrogen as per treatment details were applied during final land preparation and thoroughly mixed in https://www.agric.wa.gov.au/ nitrogen fertilization on growth and yield of oat 37 the soil. remaining half dose of nitrogen was top dressed after 30 days of seed sowing. the other intercultural operations were kept normal and uniform for all the treatment plots. table 1. list of treatments followed in the experiment treatments treatment description nitrogen rate (kg ha-1) t0 no nitrogen (control) 0 t1 33.75% less than recommended 30 t2 22.5% less than recommended 45 t3 11.25% less than recommended 60 t4 recommended dose 75 t5 11.25% more than recommended 90 t6 22.5% more than recommended 105 weather information: a summary of the mean fortnightly temperatures, relative humidity, soil temperature and total monthly precipitation is provided in table 2. growing season air temperatures were average to below average and precipitation was average to above average during the study period. table 2. fortnightly weather data at the experimental field area during the growing season month & fortnight air temperature (°c) relative humidity (%) soil temperature (°c) at different soil depths (cm) rainfall (mm) max. min. max. min. 5 20 november’17 19.40 1 31.90 19.00 98.00 50.00 19.70 24.20 2 28.55 18.50 97.00 53.50 23.90 25.25 december’17 50.30 1 27.25 17.25 99.50 61.00 22.00 23.40 2 25.70 15.15 98.50 61.00 20.55 22.55 january’18 nil 1 22.20 10.55 97.00 50.50 17.25 19.10 2 25.30 11.50 99.50 40.50 18.35 20.20 february’18 nil 1 28.90 16.40 96.50 39.50 21.90 22.20 2 31.15 18.35 97.50 40.50 23.95 24.15 march’18 1.20 1 33.70 20.45 95.50 36.50 27.30 27.20 2 33.80 23.05 96.50 47.00 29.80 29.60 april’18 76.00 1 33.70 21.70 94.50 48.50 29.10 29.70 2 35.20 24.55 94.00 54.00 30.35 30.60 *source: regional weather station, khulna, bangladesh variables measured ten plants from each plot were selected randomly and data on plant height, leaves plant -1 , tiller plant -1 , and numbers of filled and unfilled grains spike -1 were recorded. plant height was measured from the soil level to the highest leaf tip with the help of a meter tape. three rows from each plot were randomly selected and then numbers of plants were counted from one meter length of each row. ten randomly selected plants from each plot of each replication were taken into account and numbers of tillers plant -1 were counted and their averages were worked out. all the plants of each plot of each replication were harvested and tied into bundles. after threshing and cleaning by winnowing, grain yield and total stover plot -1 were measured separately with electric balance and digital scale balance, respectively. the yield was converted on hectare basis in tones. grain yield was calculated based on a cleaned sample with a moisture level adjusted to 14%. 38 islam et al. data analysis: the data were analyzed for analysis of variance (anova) at an error rate of 5% to determine the impact of each treatment by using the computer package program star (statistical tools for agricultural research). construction of graphs, calculation of means and standard errors were carried out by using microsoft office excel 2012 program. the differences among the treatment means were compared by duncan’s new multiple range test (dmrt) at 95% confidence level. functional relationships were developed between yield attributes and yield, and between treatments and yield by using simple regression analysis. results and discussion growth attributes plant height is an important morphological character that acts as a potent indicator of availability of growth resources in its vicinity. different levels of nitrogenous fertilizer had significant effects on plant height of oat at 60 days after sowing (das) and at harvest but had no significant effect at 30 das (figure 1). this may be because the uptake of nitrogen by oat plants is low during early development and increased with crop growth. although only relatively small amounts of fertilizers are required during the very early stages of plant growth, high concentration of nutrients in the roots zone at that time are beneficial in promoting early growth (hanway, 1966). vertical bars represent mean standard error. fig. 1. effect of different levels of nitrogen on plant height (cm) of oat. increasing n rate resulted a significant increase in plant height. oats that received the highest n rate produced taller plants. at 60 das as well as at harvest, the highest plant height was observed for 22.5% more than recommended doses of nitrogenous fertilizer. throughout the growth period, the minimum plant height was recorded for the plants receiving no additional nitrogen (control). the increase in plant height with nitrogen fertilizer is due to the fact that nitrogen promotes plant growth, increases the number of internodes and length of the internodes which results in progressive increase in plant height (gasim, 2001). mangesh (2016) found that application of nitrogen at 100 kg ha -1 recorded significantly higher plant height as compared to application of 60 kg ha -1 . maral et al. (2013) found maximum plant height by applying 98 kg ha -1 nitrogenous fertilizer in oats. these findings are in agreement with this experimental result. other growth attributes besides plant height of oats viz., leaves plant -1 , tillers plant -1 and plant density (m -2 ) were recorded at different intervals of crop to analyze the performance and progress of crop growth. all the growth attributes of oats were significantly influenced by different levels of nitrogen 0 20 40 60 80 100 120 at 30 das at 60 das at harvest p la n t h e ig h t (c m ) ns (cv=17.96%) t0 t1 t2 t3 t4 t5 t6 p≤0.01 (cv=8.20%) p≤0.01 (cv=8.02%) nitrogen fertilization on growth and yield of oat 39 application (table 3). maximum leaves plant -1 , tillers plant -1 and plant density (m -2 ) were obtained with application of 105 kg ha -1 n throughout the growing period. statistically the maximum number of leaves plant -1 (11.90) at harvest was observed when 105 kg ha -1 n was applied followed by the application of 90 kg ha -1 n. the minimum number of leaves plant -1 (6.43) was recorded in control. the rest of the treatments in respect of the number of leaves plant -1 were intermediate. the variation in number of leaves plant -1 may be due to the timely availability of n from applied fertilizer. statistically the maximum number of tillers plant -1 (9.93) was observed when 105 kg ha -1 n was applied followed by 90 kg n ha -1 . while the minimum number of tillers 6.87 were observed where no additional n was applied (control). fertilizer treatments tended to influence plant density in oats. the statistically significant variation in plant density in oat suggesting that the addition of n resulted in measurable seedling growth under the conditions of this study. these findings are in line with godara et al. (2016) who reported that all growth parameters were influenced significantly by increasing levels of nitrogen from 40 to 120 kg ha -1 . sheoran et al. (2017) revealed that number of tillers m -1 row length were influenced significantly with increasing levels of nitrogen from 40 to 120 kg ha -1 . anay et al. (2012) revealed that the leaves plant -1 and number of tillers plant -1 in oats increased significantly with each increment of 40 kg n from 0-100 kg ha -1 . table 3. effect of different levels of nitrogenous fertilizer on growth attributes of oat (avena sativa l.) n level (kg ha-1) no. of leaves plant-1 no. of tillers plant-1 plant density (m-2) 30 das 60 das harvest 30 das 60 das harvest 30 das 60 das harvest 00 4.67±0.34e 5.80±0.07e 6.43±0.02e 6.37±0.12d 6.73±0.10e 6.87±0.12e 28.67±0.51e 28.33±0.51f 29.33±.51e 30 5.00±0.07de 6.50±0.09de 6.97±0.12de 6.67±0.08d 7.23±0.17de 7.37±0.14de 31.00±0.33d 31.67±0.19e 32.33±0.19d 45 5.47±0.17de 7.27±0.14cd 7.83±0.07cd 7.10±0.12cd 7.47±0.16de 7.73±0.17d 32.00±0.33cd 33.33±0.19de 33.67±0.19d 60 5.97±0.27cd 8.20±0.29c 8.73±0.21c 7.70±0.17bc 8.00±0.14cd 8.17±0.13cd 33.67±0.19c 34.67±0.19cd 34.67±0.19cd 75 6.63±0.28bc 9.37±0.28b 9.97±0.32b 8.37±0.19ab 8.67±0.15bc 8.87±0.14bc 35.67±0.19b 37.00±0.33bc 37.00±0.33bc 90 7.47±0.32ab 10.00±0.31b 10.73±0.37ab 8.70±0.20a 9.33±0.13ab 9.40±0.15ab 37.00±0.33b 39.00±0.0ab 39.33±0.19ab 105 8.13±0.26a 11.37±0.20a 11.90±0.23a 9.10±0.19a 9.87±0.08a 9.93±0.09a 39.33±0.19a 40.67±0.19a 41.33±0.19a ls ** ** ** ** ** ** ** ** ** cv (%) 5.92 4.60 4.72 4.52 3.64 3.47 1.93 2.47 2.34 ls= level of significance, cv= co-efficient of variation, **= significant at 1% level of probability, means followed by the same letter(s) within columns are not significantly different at p≤0.05. yield attributes yield and all yield contributing characters except harvest index of oat were affected significantly with varying levels of n (table 4). spike length of oat was affected significantly by n rate. a linear increased in spike length was found with progressively greater n rates (table 4). the greater spike length (38.33 cm) was recorded for the plants supported with 105 kg ha -1 n which was statistically similar with the spike length (36.00 cm) produced by the plants that received 90 kg n ha -1 . the shortest spike (13.67 cm) was found for the plants under control. this may be due to the fact that low level of nitrogen leads to slow growth and low cell division, thus shortening the length of the spike. mantai et al. (2016) stated that different levels of nitrogen could significantly increase the panicle length and the panicle weight in oats. filled grains spike -1 also increased with greater levels of n indicating that greater filled grains spike -1 compensated the cost for increased rate of n (table 4) but nitrogen rate had an opposite impact on unfilled grains spike -1 and there was a linear decrease in unfilled grains spike -1 with an increase in n rate up to 90 kg ha -1 . the maximum filled grains spike -1 (37.80) was found for 90 kg n ha -1 and that of minimum (18.07) for control whereas for unfilled grains spike -1 , the maximum (12.40) and minimum (6.80) number were recorded for control and 90 kg n ha -1 , respectively. 40 islam et al. there was a significant increase in 1000-grain weight resulted by nitrogen levels. application of 105 kg n ha -1 gave the highest (73.00 g) while the control gave the lowest mean (54.13 g) seed weight. increasing the rate of nitrogen application may lead to an improvement in production of photosynthates at source and their transportation to sink efficiency. mohr et al. (2007) recorded that 1000-grain weight is higher at the rate of 80 kg ha -1 nitrogen application. a gradual increase in the application of nitrogen resulted a small but statistically significant increase in grain yield, the summation of all yield components of oats. the highest mean grain yield (1.76 t ha -1 ) was achieved for 90 kg n ha -1 while the lowest grain yield (0.73 t ha -1 ) was for control. but the mean grain yield was leveled off at higher n rate (105 kg ha -1 ) although the decrease was very slight. the increasing in nitrogen levels led to increasing of plant height (figure 1), leaves plant -1 , tillers palnt -1 , plant density (table 3), spike length, filled grains spike -1 and 1000-grain weight (table 4) which led to increasing of grain yield in oat. nitrogen also plays an important role in increasing the fertility of most florets compared to the low levels (hanif and langer, 1972). these findings were corresponded with the results reported by mantai et al. (2016). joon et al. (1993) observed that the grain yield of oats increased only up to 80 kg n ha -1 and decreased thereafter with increasing nitrogen. mohr et al. (2007) showed that low to moderate nitrogen rates significantly increased yield with optimum relative yield achieved with a plant available n supply of approximately 100 kg ha -1 . the stover yield of oat was significantly affected by nitrogen application. application of 105 kg n ha -1 showed significant superiority over that of control. the next best result was found for 90 kg ha -1 . such a positive yield response may be due to the increase in vegetative production and dry matter accumulation with successive levels of nitrogen application. increased application of nitrogen, therefore, provides better nutrition to oats which resulted in maximum stover yield. midha et al. (2015) found that increasing rates of nitrogen application up to 120 kg ha -1 significantly enhanced the forage yield over the lower doses of nitrogen. the effect of nitrogen doses on harvest index of oat was not significant. the lowest harvest index (25.42%) was calculated for 105 kg ha -1 nitrogen application but interestingly, the highest value (30.51%) was at 30 kg n ha -1 rate. sharma et al. (2001) revealed that application of 100 kg n ha -1 significantly increased the grain and straw yields and harvest index was significantly reduced by nitrogen fertilization. table 4. effect of different levels of nitrogenous fertilizer on yield and yield attributes of oat (avena sativa l.) n level (kg ha-1) spike length (cm) no. of filled grains spike-1 no. of unfilled grains spike-1 1000-grain weight (g) grain yield (t ha-1) stover yield (t ha-1) harvest index (%) 00 13.67±0.51d 18.07±0.37e 12.40±0.76a 54.13±0.99d 0.73±0.02d 1.99±0.16e 27.45±1.89 30 21.33±0.51c 21.67±0.58d 9.00±0.31ab 56.43±0.55cd 1.03±0.07cd 2.39±0.21de 30.51±2.39 45 25.67±0.83c 25.80±0.35c 8.93±0.49ab 58.13±1.00bcd 1.13±0.03bcd 2.99±0.08cd 27.49±0.76 60 27.00±0.67bc 28.53±0.26c 8.33±0.17ab 61.57±2.33bcd 1.34±0.06abc 3.56±0.18bc 27.59±1.75 75 32.33±0.84ab 34.00±0.57b 7.73±1.00ab 64.20±1.79abc 1.44±0.08abc 3.87±0.20abc 27.30±1.88 90 36.00±0.67a 37.80±0.55a 6.80±0.55b 67.60±1.95ab 1.76±0.14a 4.32±0.14ab 28.82±1.81 105 38.33±0.69a 35.67±0.40ab 7.47±0.27b 73.00±3.23a 1.61±0.09ab 4.70±0.03a 25.42±1.07 ls ** ** * ** ** ** ns cv (%) 7.69 3.59 19.88 5.35 13.80 9.03 12.84 ls= level of significance, cv= co-efficient of variation, **= significant at 1% level of probability, *= significant at 5% level of probability, ns= not significant, data followed by same letter (s) are not different statistically. although yield varied considerably with the variation in nitrogen rate, reasonably close and positive linear relationships were evident between relative grain yield and panicle length (r 2 = 0.93), grain yield and filled grains panicle -1 (r 2 = 0.91), grain yield and rate of n (r 2 = 0.92) and straw yield and n rate (r 2 = 0.98) (figure 2). optimum relative grain yield was achieved with plants supplied 90 kg n ha -1 and that of straw yield with 105 kg n ha -1 suggesting that a higher rate of nitrogen was required to optimize yield in oat. the regression analysis revealed that more than 90% variation in grain yield as nitrogen fertilization on growth and yield of oat 41 well as in straw yield could be explained by the variation in nitrogen rate. previous works were also reported similar results indicating that increased grain yield values due to increased nitrogen rates (rocquigny et al., 2004; muurinen et al., 2007). vertical bars represent mean standard error. fig. 2. functional relationships between yield parameters and grain yield, and between n levels and yield (grain and straw). conclusion yield and yield contributing characters of oat were responsive to increased amount of nitrogen up to 105 kg n ha -1 . however, 90 kg n ha -1 was the best for grain yield in oat cultivation in soils of aez-13 region. references anay, r., s.b. agrawal and p. naveen. 2012. effect of soil enrichment in conjunction with bio-organics and chemical fertilizers on yield and quality of fodder oat (avena sativa l.). j. trop. for. sci. 28(3): 59-63. https://www.cabdirect.org/cabdirect/abstract/20143096976 barut, a.a. 2003. the effect of sowing time and seed size on yield and yield components in some oat types (avena sativa l.): phd thesis//ankara university, institute of natural and applied science, turkey, pp. 114 duke, j.a. 1983. handbook of energy crops. purdue university, center for new crops & plants products, india. eagri. 2012. oats, rye and triticale origin, geographic distribution, economic importance, soil and climatic requirement, varieties, cultural practices and yield. http://eagri.org/eagri50/agro302/lec05.pdf. gasim, s.h. 2001. effect of nitrogen, phosphorus and seed rate on growth, yield and quality of forage maize (zea mays l.). m.sc. thesis, faculty of agriculture, university of khartoum. y = 0.0404x + 0.1753 r² = 0.9257 0.0 0.5 1.0 1.5 2.0 0 20 40 60 g ra in y ie ld ( t h a -1 ) panicle length (cm) grain yield y = 0.0465x 0.0434 r² = 0.9118 0.0 0.5 1.0 1.5 2.0 0 20 40 60 g ra in y ie ld ( t h a -1 ) filled grains spike-1 grain yield y = 0.0096x + 0.7411 r² = 0.9196 0.0 0.5 1.0 1.5 2.0 -20 0 20 40 60 80 100 120 g ra in y ie ld ( t h a -1 ) nitrogen rate (kg ha-1) grain… y = 0.0273x + 1.8261 r² = 0.9823 0.0 2.0 4.0 6.0 -50 0 50 100 150s tr a w y ie ld ( t h a -1 ) nitrogen rate (kg ha-1) straw yield https://www.cabdirect.org/cabdirect/abstract/20143096976 http://eagri.org/eagri50/agro302/lec05.pdf 42 islam et al. godara, a.s., b.s. satpal and s.k. duhan. 2016. effect of different nitrogen levels on forage yield, quality and economics of oat (avena sativa l.) genotypes. forage res. 41(4): 233-236. hanif, m. and r.h.m. langer. 1972. the vascular system of the spike let in wheat (triticum aestivum). ann. bot. 36(4): 721-727. hanway, j.j. 1966. how a corn plant develops. special report no. 38, iowa state university of science and technology, cooperative extension service. https://www.agric.wa.gov.au/. accessed on: 27.12.2019. jackson, g.d., r.k. berg, g.d. kushnak, t.k. blake and g.i. yarrow. 1994. nitrogen effects on yield, betaglucan content, and other quality factors of oat and waxy hulless barley. commun. soil sci. plant anal. 25(17-18): 3047–3055. joon, r.k., b.d. yadav and a.s. faroda. 1993. effect of nitrogen and cutting management on grain production of multi-cut oat (avena sativa). indian j. agron. 38(1): 19-21. koul, g.g. 1997. effect of sowing methods, nitrogen levels and seed rates on yield and quality of fodder maize (zea mays l.). m.sc. thesis, faculty of agriculture, university of khartoum. mangesh, s.s. 2016. effect of different levels of nitrogen on performance of fodder oat (avena sativa l.) varieties under lateritic soil of konkan region. m.sc. thesis, dr. balasahed sawant konkan krishi vidyapeeth, dapoli (agricultural university), ratnagiri (maharashtra), india. mantai, r.d., j.a. gonzalez de siva, e. gh. arenhardt, o.b. scremin, a.t. woschinski de mamann, r.z. frantz, a.c. valdiero, r. pretto and d.k. krysczun. 2016. simulation of oat grain (avena sativa) using its panicle components and nitrogen fertilizer. afr. j. agric. res. 11(40): 39753983. doi: 10.5897/ajar2016.10943 maral, h., z. dumlupinar, t. dokuyucu and a. akkaya. 2013. response of six oat (avena sativa l.) cultivars to nitrogen fertilization for agronomical traits. turkish j. field crop. 18(2): 254-259. may, e.w., r.m. mohr, g.p. lafond, a.m. johnston and f.c. stevenson. 2004. effect of nitrogen, seeding date and cultivar on oat quality and yield in the eastern canadian prairies. can. j. plant sci. 84(4): 1025-1036. mengistu, a. 1997. conservation-based forage development for ethiopia. self help development international, addis ababa, ethiopia. p.170. midha, l.k., b.s. duhan and s.k.m. arya. 2015. performance of promising entries of oat (avena sativa l.) under different nitrogen levels. forage res. 41(2): 122-125. mohr, r.m., c.a. grant, w.e. may, and f.c. stevenson. 2007. the influence of nitrogen, phosphorus and potash fertilizer application on oat yield and quality. can. j. soil sci. 87(4): 459-468. muurinen, s., j. kleemola and p. peltonen-sainio. 2007. accumulation and translocation of nitrogen in spring cereal cultivars differing in nitrogen use efficiency. agron. j. 99(2): 441-449. doi: 10.2134/agronj2006.0107 omer, e.a. 1998. farm yard manure and urea fertilization on growth and forage yield of two maize (zea mays l.) cultivars. m. sc. thesis, faculty of agriculture, university of khartoum. peterson, d.m., d.m. wesenberg, d.e. burrup and c.a. erickson. 2005. relationships among agronomic traits and grain composition in oat genotypes grown in different environments. crop sci. 45(4): 1249-1255. doi: 10.2135/cropsci2004.0063 rocquigny, p.j., m.h. entz, r.m. gentile and s.c. duguid. 2004. yield physiology of a semi dwarf and tall oat cultivar. crop sci. 44(6): 2116-2122. doi: 10.2135/cropsci2004.2116 sharma, m.s., b.p. singh and s.d. mishra. 2001. influence of cutting schedules, nitrogen and phosphorus levels on growth and yield of oat. range manag. agrofor. 22(1): 60-64. sheoran, r.s., u.n. satpal joshi, b.s. duhan, p. kumari, s. arya and d.s. phogat. 2017. agronomic evaluation of oat (avena sativa l.) genotypes for forage yield, quality and economics under varying levels of nitrogen. forage res. 43(1): 35-38. https://www.agric.wa.gov.au/ https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.5897%2fajar2016.10943?_sg%5b0%5d=9wa9h5gyystw5phjc0o60hyf5l-ldpsgtugq7w1p4_9m1ma3znuom0sqfqezys6stiqr_zrggdhkimkoiihpuoceiq.qajgasib-56_t90z-arim083srmyph8rcyqduj_3hewz7cx5bk8xyiu9xx6capdzsi4k-1nurrdvxi6g7atdkq https://www.cabdirect.org/cabdirect/search/?q=pb%3a%22self+help+development+international%22 https://www.cabdirect.org/cabdirect/search/?q=pb%3a%22self+help+development+international%22 https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.2134%2fagronj2006.0107?_sg%5b0%5d=qvrd1i8kne7onwikenlltnitc3r3nqblxmnizkqp7okrwme83gh4okijkaad5wy5-yztwvwywojv44xeu237hstbsg.vuff2v8xpnmjnehobz9zsaealq2ej9srfos1bnda820xzb_nz9hmjeteqjhybyjqi69mc1yedz0reiksfemcjq https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.2135%2fcropsci2004.2116?_sg%5b0%5d=beulvudjysvggebvwqu4mwk-b4wj8llmsdgln-skweg52hwkwqojukcabkzzpf_hp-wapx4cghejzmq-ywqidtbxzw.blnuwlehsv4bvrtvo4lo2ejtnh94yfuomdh1bn-mup4epyibq3k30ra_cnfii3wnug6z8sic3iwgrfzyz_sb1g bangladesh agron. j. 2021, 24(1): 83-92 influence of planting method and nitrogen dose on growth and yield of quinoa (chenopodium quinoa willd.) p.k. biswas1, k. fatema2 and a. rahman3 1prof., 3assoc. prof., department of agronomy, sau 2ms student, department of entomology, sau dhaka-1207, bangladesh corresponding e-mail: parimalbiswas@hotmail.com (received: 10 april 2021, accepted: 18 april 2021) keywords: growth, yield, seedling, nitrogen, quinoa abstract the experiment was conducted at sher-e-bangla agricultural university, dhaka during rabi season 2018-19 to find out the influence of planting methods and nitrogen dose on growth and yield of quinoa-a highly nutritious super food newly introduced in bangladesh. the experiment was laid out in a split-plot design with 3 replications. two planting methods viz., i) seed sowing (m1) and ii) seedling planting (m2) in the main plot and eight nitrogen doses viz., i) control (f1), ii) 50 kg n ha-1 (f2), iii) 100 kg n ha-1 (f3), iv) 150 kg n ha-1 (f4), v) 180 kg n ha-1 (f5), vi) 200 kg n ha-1 (f6), vii) 220 kg n ha-1 (f7) and ix) 250 kg n ha-1 (f8) in the sub-plot were assigned. almost all the studied characters were found statistically significant due to variation in treatments. the higher plant height, leaf number plant-1, branch number plant-1 and inflorescence height were observed in seedling transplantation than seeds sowing. increment of nitrogen doses increased the plant height, leaves number plant-1, branch number plant-1, inflorescence height and spad value up to 150-200 kg n ha-1 and then decreased. higher doses of nitrogenous fertilizer application increased the grain weight. planting seedling with 150 kg n ha-1 showed the highest seed yield (1227.43 kg ha-1) which was similar to 180 kg n ha-. cultivation of quinoa with 25 days old seedlings and 150 kg n ha-1 gave 206.77% higher yield compared to that of control and it was 64.71% higher in case of seeds sowing with similar nitrogen dose. introduction quinoa (chenopodium quinoa willd.) has been recognized as a climate resilient crop of great value with most nutritious food crops and the seeds contains high quality protein, which has all the essential amino acids including lysine, methionine and threonine that are scarce in cereals and legumes (repo-carrasco et al., 2003). food and agriculture organization (fao) has identified quinoa as one of the crops that will play an important role in ensuring future food security and designated the year 2013 as the “year of quinoa” (bazile et al., 2015). worldwide, the demand for quinoa is growing, especially in the health food segment, but current supplies are inadequate. besides the use for human consumption, quinoa seed has other uses as livestock and poultry feed. the whole plant can be used as green fodder and harvest residues can be fed to the animals. quinoa seeds are an exceptionally nutritious food source, owing to their high protein content with all essential amino acids, lack of gluten, and high content of several minerals such as ca, mg, fe, and it is also rich in vitamins (bhargara et al., 2006). 84 biswas et al. worldwide quinoa is cultivating using true seeds as planting material, but ramesh et al. (2019) reported that the crop can also be cultivate using 20 days old seedlings. hirich (2014) reported that application and suggested the increased seed yield with increasing nitrogen supply. the yield was highest in the 50% of full irrigation with 240 kg n ha−1. another experiment conducted by shams (2011) with nitrogen fertilization showed that high nitrogen fertilizer dose significantly increased quinoa yield. alandia et al. (2016) reported that quinoa is a crop which can profit from relatively high levels of n-application under north european conditions. agronomy department of sher-e-bangla agricultural university has been working with quinoa and agronomic management package have been identified where november as the optimum sowing time of quinoa in bangladesh (biswas and tanni, 2020). the national seed board also registered the crop as „sau quinoa-1‟ to cultivate in the country. the study was therefore undertaken with planting methods and nitrogen dose to find out the maximum yield potentiality of quinoa. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka during the period from november 2018 to april 2019. the farm belongs to the general soil type, shallow red brown terrace soils under tejgaon series of aez-28. the seeds of „sau quinoa-1‟ was used. the land was finally leveled with leveler to ensure uniform application of water. urea for nitrogen as per treatment along with tsp and mop @ 100 kg p & 80 kg k ha-1, respectively were used. the whole amount of all fertilizers along with one third of urea was applied as a basal dose and the remaining urea was top dressed in two equal installments at 30 and 45 days after sowing. the seeds were sown on 20 november, 2018 in the main field as well as in surrounding nursery bed from where 25 days old seedlings were uprooted and planted in respective plots maintaining 30 cm x 10 cm spacing. the experiment was laid out in a split-plot design with three replications. there were two planting methods viz., i) seed sowing (m1) and ii) seedling planting (m2) assigned in the main plot and eight nitrogen dose viz., i) control (f1), ii) 50 kg n ha-1 (f2), iii) 100 kg n ha-1 (f3), iv) 150 kg n ha-1 (f4), v) 180 kg n ha-1 (f5), vi) 200 kg n ha-1 (f6), vii) 220 kg n ha-1 (f7) and ix) 250 kg n ha-1 (f8) in the sub-plot. the gap filling, weeding and other intercultural operations were done as and when necessary. no severe insects and disease infestations were observed during experimentation. the seeds sowing plots were harvested 10 february, 2019 and seedling transplanting on 20 february, 2019. ten plants per plot was randomly selected for collecting yield contributing and other relevant data like plant height, leaves number plant-1, branch number plant-1, inflorescence height, spad value, 1000grain weight and grain yield. the harvested plants were sundried and threshed from where collected seeds were dried to a constant temperature and weighed. statistical analyses were done by using the crop stat computer package and the mean differences among the treatments were compared by least significant difference test (lsd) at 5 % level of significance following gomez and gomez (1984). results and discussion plant height effect of planting method plant height at 21 and 35 days after sowing/planting (das/p) and at harvest was significantly differed for planting method (table 1). the tallest plant at 21 dap (12.95 cm), 35 dap (56.67 influence of planting method and nitrogen dose on quinoa 85 cm) and at harvest (55.62 cm) was found in seedling planting compared to that of seed sowing. planting seedling showed 38.80, 12.89 and 6.88% taller plants at 21, 35 das/planting and at harvest, respectively compared to that of the plants from seed. biswas and tanni (2020) was found higher plant height (62.47 cm) of quinoa from sowing seeds at november 10. table 1. effect of planting method and nitrogen dose on plant height and leaves number plant-1 of quinoa treatments plant height (cm) at leaves plant-1 (no.) 21 das/p 35 das/p harvest 21 das/p 35 das/p planting material: m1 m2 9.33 b 12.95 a 50.20 b 56.67 a 52.04 55.62 12.03 b 35.95 a 71.71 68.93 lsd (0.05) cv (%) 1.103 8.20 4.084 4.98 ns 8.25 4.694 15.21 ns 30.77 nitrogen dose: f1 f2 f3 f4 f5 f6 f7 f8 10.41 bcd 10.84 bcd 10.09 cd 9.83 d 11.71 ab 11.51 bc 11.64 ab 13.07 a 44.95 c 50.38 bc 53.92 ab 54.86 ab 57.55 a 56.17 a 55.19 ab 54.43 ab 47.55 c 52.37 abc 50.88 bc 54.32 ab 55.86 ab 56.41 a 56.81 a 56.45 a 19.17 b 22.50 ab 24.95 ab 22.73 ab 27.43 a 26.68 a 24.33 ab 24.13 ab 61.47 c 73.77 ab 76.30 ab 77.53 a 75.43 ab 66.77 abc 66.45 abc 64.85 bc lsd(0.05) cv (%) 1.489 11.27 5.499 8.70 5.160 8.11 6.321 22.28 11.990 14.42 m1 = sowing seeds, m2 = planting seedlings, f1 = 0 kg n ha-1, f2 = 50 kg n ha-1, f3 = 100 kg n ha-1, f4 = 150 kg n ha-1, f5 = 180 kg n ha-1, f6 = 200 kg n ha-1, f7 = 220 kg n ha-1, f8 = 250 kg n ha-1 effect of nitrogen dose plant height of quinoa was significantly influenced by nitrogen dose at all studied dates. at 21 das/p, the highest plant height (13.07 cm) was recorded in f8 (250 kg n ha-1) that similar to f7 and f5 whereas the lowest plant height (9.83 cm) by f4 that similar to f3, f2 and f1 (table 1). almost similar trend was also observed at 35 das/p but at harvest, application of 150 to 250 kg n ha-1 resulted similar and significantly higher plant height and no nitrogen application treatment gave the shortest plant height (47.55 cm). geren (2015) also reported that the plant height of quinoa increased noticeably by increasing nitrogen fertilizer rate up to 175 kg n ha-1. fawy et al. (2017) reported 33% higher plant height of quinoa by 240 kg n ha-1 whereas weisany et al. (2013) also reported 33% higher plant height of quinoa by soil application of nitrogen than control. interaction effect of planting method and nitrogen dose the interaction effect of planting method and nitrogen dose showed significant variations of plant height. the tallest plant at 21 das/p was given by m2f8 (16.30 cm) that similar to m2f7 (15.30 cm) and the shortest plant (8.08 cm) found in m1f7 that similar to all nitrogen levels under seed sowing. at 35 das/p, the tallest plant (61.37 cm) was resulted in m2f3 that similar to all nitrogen doses of seedling planting except no nitrogen application and the shortest plant (43.30 cm) observed in m1f1 which was at par with m1f2, m1f4, m1f4 and m2f1combinations (table 2). at harvest, the tallest plant (60.53 cm) was found in m1f5 and the shortest plant (43.11 cm) at m1f1. 86 biswas et al. number of leaves plant-1 effect of planting method the maximum number of leaves plant-1 (35.95) at 21 dap was recorded in seedling planting as compared to that of sowing seeds (12.03) but at 35 das, the scenario was reverse where maximum leaves plant (71.71) was given by the plants of seeds though no significant variation observed between them (table 1). sadia (2018) also reported 29.19 leaves plant-1 of quinoa using seeds as planting material. effect of nitrogen dose at 21 das/p, the maximum number of leaves plant-1 (27.43) was observed in f5 that similar to f6 whereas the lowest number of leaves plant-1 in control plants (table 1). similar trend was also shown in 35 das/p. application of 120 kg n ha-1 gave 33.80 leaves plant-1 of quinoa as reported by sadia (2018). interaction of planting method and nitrogen dose the number of leaves plant-1 was significantly influenced by the interaction of planting method and nitrogen dose and the highest number of leaves plant-1 at 21 das/p was observed in m2f5 (41.80) that similar to m2f6 (41.03). no variation was recorded among the interactions of m1 irrespective of all nitrogen doses (table 1) that exhibited the lower number of leaves plant-1. the scenario was different at 35 das/p where m1f5 resulted the highest number of leaves plant-1 and the lowest in m2f1 interaction (59.13). table 2. effect of planting method and nitrogen dose on plant height and number of leaves plant-1 of quinoa treatments plant height (cm) at leaves plant-1 (no.) at 21 das/p 35 das/p harvest 21 das/p 35 das/p m1f1 m1f2 m1f3 m1f4 m1f5 m1f6 m1f7 m1f8 m2f1 m2f2 m2f3 m2f4 m2f5 m2f6 m2f7 m2f8 9.49 c-f 10.41 cde 9.04 def 8.95 ef 9.81 c-f 8.99 ef 8.08 f 9.85 c-f 11.33 c 11.27 c 11.13 cd 10.70 cde 13.60 b 14.03 b 15.20 ab 16.30 a 43.30 f 45.27 ef 46.47 def 51.00 c-f 57.40 abc 53.20 bcd 52.27 b-e 52.67 b-e 46.60 def 55.49 abc 61.37 a 58.72 abc 57.70 abc 59.13 ab 58.11 abc 56.20 abc 43.11 f 48.07 def 45.67 ef 54.30 a-d 60.53 a 54.79 a-d 55.93 abc 53.90 a-d 51.99 b-e 56.67 abc 56.09 abc 54.33 a-d 51.19 cde 58.03 abc 57.68 abc 59.00 ab 13.20 d 12.93 d 11.67 d 10.67 d 13.07 d 12.33 d 10.80 d 11.60 d 25.13 c 32.07 bc 38.23 ab 34.80 ab 41.80 a 41.03 a 37.87 ab 36.67 ab 63.80 bcd 68.07 a-d 69.33 a-d 77.00 abc 84.67 a 68.27 a-d 74.33 a-d 68.20 a-d 59.13 d 79.47 ab 83.27 a 78.07 abc 66.20 bcd 65.27 bcd 58.57 d 61.50 cd lsd(0.05) cv (%) 2.09 11.27 7.78 8.70 7.30 8.11 8.94 22.28 16.96 14.42 m1 = sowing seeds, m2 = planting seedlings, f1 = 0 kg n ha-1, f2 = 50 kg n ha-1, f3 = 100 kg n ha-1, f4 = 150 kg n ha-1, f5 = 180 kg n ha-1, f6 = 200 kg n ha-1, f7 = 220 kg n ha-1, f8 = 250 kg n ha-1 influence of planting method and nitrogen dose on quinoa 87 number of branches plant-1 effect of planting method the higher number of branches plant-1 at harvest was recorded from the plants of seedling (19.87) compared to that of seeds (10.89) which was 82.46% higher (table 3). sadia (2018) reported 17.67 branches plant-1 of quinoa from seeds as planting method. effect of nitrogen dose application of various levels of nitrogen resulted significant variations on branch number plant-1 of quinoa and the 100 kg n-1 gave highest number of branches plant-1 (17.07) that similar to all other doses except control, 220 and 250 kg n ha-1 (table 3). the lowest number of branches plant-1 (11.53) was found in 250 kg n ha-1. application of 120 kg n ha-1 resulted 20.00 branches plant-1 of quinoa as reported by sadia (2018). table 3. effect of planting method and nitrogen dose on yield and other crop characters of quinoa treatments branches plant1 (no.) inflorescence length (cm) spad value 1000-seed weight (g) seed yield (kg ha-1) planting material: m1 m2 10.89 b 19.87 a 23.69 b 41.28 a 55.53 55.66 2.94 2.97 945.46 934.15 lsd(0.05) cv (%) 1.67 11.18 3.62 5.01 ns 6.06 ns 3.20 ns 7.68 nitrogen dose: f1 f2 f3 f4 f5 f6 f7 f8 15.07 bc 16.60 ab 17.07 a 16.77 ab 16.40 ab 15.63 abc 13.97 c 11.53 d 26.53 c 29.95 bc 33.20 ab 36.02 a 33.53 ab 35.98 a 32.92 ab 31.77 ab 38.13 d 46.02 c 55.77 b 59.34 ab 57.75 b 64.61 a 61.85 ab 61.32 ab 2.67 d 2.75 c 2.87 b 3.06 a 3.06 a 3.09 a 3.08 a 3.10 a 538.19 f 756.71 e 993.22 cd 1170.64 a 1097.77 ab 1033.37 bc 1003.73 cd 924.80 d lsd(0.05) cv (%) 1.83 10.08 4.87 12.67 6.20 9.44 0.06 1.80 87.24 7.85 m1 = sowing seeds, m2 = planting seedlings, f1 = 0 kg n ha-1, f2 = 50 kg n ha-1, f3 = 100 kg n ha-1, f4 = 150 kg n ha-1, f5 = 180 kg n ha-1, f6 = 200 kg n ha-1, f7 = 220 kg n ha-1, f8 = 250 kg n ha-1 interaction of planting method and nitrogen dose interaction of planting method and nitrogen dose showed significant variations for branches number plant-1 where m2f3 gave significantly the higher number of branches plant-1 (23.13) that similar to m2f4 (22.80) and m2f2 (22.67) but the lowest number of branches plant-1 in m1f1 (9.80) that similar to all other nitrogen doses of seeds sowing method except m1f5 (table 4). biswas and tanni (2020) reported 25.20 branches plant-1 of quinoa from november-10 sowing of seeds with 180 kg n ha-1. inflorescence length at harvest effect of planting method the higher length of inflorescence was recorded in seedling planting (41.28 cm) compared to that of seeds sowing (23.69 cm) which was 74.25% higher than seed sowing method (table 3). 88 biswas et al. similar inflorescence length (22.01 cm) of quinoa using seeds as planting material was also reported by biswas and tanni (2020). ramesh et al. (2019) also reported similar inflorescence length (19.00-23.50 cm) of quinoa in india. effect of nitrogen dose application of various levels of nitrogen fertilizer resulted significant variations on inflorescence length of quinoa and the 200 kg n-1 gave maximum length (36.02 cm) that similar to all other doses except control and 50 kg n ha-1 (table 3). the lowest inflorescence length (26.53 cm) was found in control plots. application of 120 kg n ha-1 resulted 18.56 cm length of inflorescence as reported by sadia (2018). interaction of planting method and nitrogen dose interaction of planting material and nitrogen dose showed significant variations for inflorescence length where m2f3 gave maximum length (45.13 cm) that similar to almost all other treatments of seedling planting except m2f2 and m2f1 and all treatments of seeds sowing. the lowest inflorescence length (17.50 cm) was observed in m1f1 that similar to m1f2, m1f3, m1f7 and m1f8 interactions (table 4). similar inflorescence length (21.10-31.70 cm) was also reported by rao and shahid (2012). table 4. interaction effect of planting method and nitrogen dose on yield and other crop characters of quinoa treatment combinations branches plant-1 (no.) inflorescence height (cm) spad value 1000-seed weight (g) seed yield (kg ha-1) m1f1 m1f2 m1f3 m1f4 m1f5 m1f6 m1f7 m1f8 m2f1 m2f2 m2f3 m2f4 m2f5 m2f6 m2f7 m2f8 9.80 e 10.53 de 11.00 de 10.73 de 12.40 de 11.00 de 11.07 de 10.60 de 20.33 b 22.67 ab 23.13 a 22.80 ab 20.40 b 20.27 b 16.87 c 12.47 d 17.50 h 21.10 gh 21.27 fgh 28.13 ef 28.97 de 27.63 efg 23.83 e-h 21.10 gh 35.57 cd 38.80 abc 45.13 a 43.90 ab 38.10 bc 44.33 ab 42.00 abc 42.43 abc 29.41 h 40.79 g 58.53 a-e 64.34 ab 59.36 a-e 66.37 a 63.47 ab 61.99 abc 46.84 f 51.24 ef 53.00 def 54.35 c-f 56.14 b-e 62.85 abc 60.23 a-d 60.65 a-d 2.62 d 2.72 c 2.88 b 3.06 a 3.08 a 3.06 a 3.05 a 3.09 a 2.71 c 2.77 c 2.87 b 3.06 a 3.03 a 3.11 a 3.12 a 3.12 a 676.24 g 841.53 f 939.12 def 1113.85 abc 1060.90 bcd 1030.32 bcd 1013.79 bcd 887.90 ef 400.13 h 671.88 g 1047.31 bcd 1227.43 a 1134.65 ab 1036.42 bcd 993.66 cde 961.70 def lsd(0.05) cv (%) 2.59 10.08 6.87 12.67 8.77 9.44 0.09 1.80 123.37 7.85 m1 = sowing seeds, m2 = planting seedlings, f1 = 0 kg n ha-1, f2 = 50 kg n ha-1, f3 = 100 kg n ha-1, f4 = 150 kg n ha-1, f5 = 180 kg n ha-1, f6 = 200 kg n ha-1, f7 = 220 kg n ha-1, f8 = 250 kg n ha-1 spad value effect of planting method there was no significant variation observed between the two planting methods for spad value though the numerically higher value (55.66) was found in seedling planting compared to that of seed sowing (55.53) (table 3). influence of planting method and nitrogen dose on quinoa 89 effect of nitrogen dose various levels of nitrogen resulted significant variations on spad value of quinoa and the maximum value (64.61) was observed in 200 kg n-1 that similar to f7 (61.85), f8 (61.32) and f4 (59.34) (table 3). the lowest spad value (38.13 cm) was found in control plants. interaction of planting method and nitrogen dose interaction of planting method and nitrogen dose showed significant variations for spad value where m1f6 gave significantly the maximum value (66.37) that similar to all other nitrogen doses of seed sowing except m1f1 and m1f2 as well as m2f6, m2f7 and m2f8. the lowest spad value (29.41) was observed in m1f1 (table 4). weight of 1000 seeds effect of planting method the 1000-seed weight was not significantly varied for the two planting methods where seedlings planting gave numerically higher 1000-seed weight (2.97 g) compared to that of seeds sowing (2.94 g) (table 3). biswas and tanni (2020) reported that the 1000-seed weight of quinoa varied significantly with sowing dates that ranges from 1.17-2.58 g for march to november sowing with seed sowing method. effect of nitrogen dose application of various doses of nitrogen fertilizer resulted significant variations on 1000-seed weight and the maximum weight (3.10 g) was observed in f8 (250 kg n-1) that similar to f6 (3.09 g), f7 (3.08 g), f5 (3.06 g) and f4 (3.06 g) (table 3). the lowest 1000-seed weight (2.67 g) was found in control treatment that showed 13.87% lower weight than f8 treatment. similar higher 1000-seed weight (3.06 g) of quinoa was also reported by application of 187.50 kg n ha-1 (kansomjet et al., 2017) but dissimilar opinion was also given by basra et al. (2014) who stated that 1000-grain weight of quinoa not affected by nitrogen fertilization from 0 to 120 kg n ha-1. interaction of planting method and nitrogen dose interaction of planting method and nitrogen dose showed significant variations for 1000-seed weight where m2f8 and m2f7 gave significantly the highest identical 1000-seed weight (3.12 g) that similar to f6, f5 and f4 irrespective of their planting material (table 4). sowing seeds with 120 kg n ha-1 resulted similar (2.84 g) 1000-seed weight of quinoa as reported by sadia 92018). seed yield effect of planting method there was no significant variation of seed yield observed between the two planting methods. the numerically higher seed yield (945.46 kg ha-1) was observed in seed sowing compared to that of seedling transplanting (934.15 kg ha-1) (table 3). similar seed yield of quinoa (1.16 t ha-1) was also reported by biswas and tanni (2020). effect of nitrogen dose application of various doses of nitrogen fertilizer resulted significant variations on seed yield of quinoa and the highest yield (1170.64 kg ha-1) observed in f4 (150 kg n-1) that similar (1097.77 kg ha-1) to f5 (180 kg n-1) and followed by f6 (1033.37 kg ha-1) (table 3). the lowest seed yield 90 biswas et al. (538.19 kg ha-1) was found in control treatment. application of 150 kg n ha-1 (f4) showed 117.51% higher yield than control (no nitrogenous fertilizer application). kansomjet et al. (2017) was found higher seed yield (2641.70 kg ha-1) of quinoa by application of 93.75 kg n ha-1 and its increment reduced seed yield (lavini et al., 2014). jacobsen and christiansen (2016) reported that quinoa yield increased significantly with an application up to 180 kg n ha-1. in another study jacobsen et al. (1994) reported that seed yield in quinoa increased with increasing napplication, however, on the other hand only small yield decreases were seen when decreasing n-level from highest n application of 160 kg ha-1. interaction of planting method and nitrogen dose interaction of planting method and nitrogen dose showed significant variations for seed yield of quinoa where m2f4 gave significantly the maximum seed yield (1227.43 kg ha-1) that similar to m2f5 (1134.65 kg ha-1) and m1f4 (1113.85 kg ha-1). the lowest seed yield (400.13 kg ha-1) was observed in m2f1 that followed by m1f1 (676.24 kg ha-1) (table 4). the values obtained correspond to those reported by erley et al. (2005) that nitrogen fertilizer rates at 80 and 120 kg n ha-1 had the highest of quinoa grain yield at 3,083 and 3,495 kg ha-1, respectively. kaveeta et al. (2009), oelke et al. (1992), basra et al. (2014), carlsson et al. (1984), thanapornpoonpong (2004), shams (2012), gomaa (2013) and geren (2015) also reported that nitrogen fertilizer rates affected grain yield of quinoa due to promoting vegetative growth behaviour of nitrogen fertilizer. nitrogen had increased ability for photosynthesis and photosynthate translocation to promote grain and these results agreed with thanapornpoonpong (2004) who noticed that seed yield plant-1 increased with increasing nitrogen fertilizer rates. kansomjet et al. (2017) reported that nitrogen fertilizer rate of 93.75, 187.50 and 312.50 kg n ha-1 results on higher seed yield of quinoa than those of control. in denmark, it is recommended to apply 80–120 kg of n ha-1 at crop establishment in the spring to obtain a yield of about 2 t ha-1 of seed. in germany quinoa responded strongly to n fertilization to 120 kg n ha-1, with a 94 % yield increase compared to 0 n (schulte auf‟m erley et al., 2005). estimated yield potential may exceed the observed yields, indicating that even higher rates of nitrogen application may increase yield (hirich et al., 2013). conclusion the planting method had significant effect on plant height at earlier stages, branches number plant-1 and inflorescence height where seedling planting method showed superior performance but the other studied parameters resulted non-significant variations. the nitrogen dose significantly influenced all the studied parameters where no nitrogen (control) as well as higher nitrogen dose negatively influenced on yield and other characters. higher yield (1170.64 kg ha-1) was obtained in f4 (150 kg n-1) that similar (1097.77 kg ha-1) to f5 (180 kg n-1). the highest grain yield (1227.43 kg ha-1) was observed in m2f4 that similar to m2f5 (1134.65 kg ha-1) and m1f4 (1113.85 kg ha-1) and the lowest grain yield was observed in m2f1 (400.13 kg ha-1). based on the results of the study, it may be concluded that quinoa can also be grown in bangladesh by 25 days old seedling with 150 to 180 kg n ha-1. however, to reach a specific conclusion and recommendation more experiments are suggested with different levels of other fertilizers and in different agro-ecological zones. influence of planting method and nitrogen dose on quinoa 91 acknowledgement the author acknowledged the ministry of science and technology, govt. of the peoples republic of bangladesh for providing financial support to conduct the study at sher-e-bangla agricultural university. references alandia, g., s.-e. jacobsen, n.c. kyvsgaard, b. condori and f. liu. 2016. nitrogen sustains seed yield of quinoa under intermediate drought. j. agron. crop sci. 202: 281291, doi: 10.1111/jac.12155. basra, s.m.a., s. iqbal and i. afzal. 2014. evaluating the response of nitrogen application on growth, development and yield of quinoa genotypes. intl. j. agric. biol. 16: 886-892. bazile, d., d. bertero and c. nieto. 2015. state of the art report on quinoa around the world in 2013. rome: food and agriculture organization of the united nations (fao) & cirad (centre de coopération internationale en recherche agronomique pour le développement). bhargava, a., s. sudhir and o. deepak. 2006. quinoa (chenopodium quinoa willd.). an indian perspective. inds. crop products. 23: 73-87. biswas, p.k. and z.a. tanni. 2020. quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh: agronomic performance with sowing date. bangladesh agron. j. 23(1): 67-73. carlsson, r., p. hanczakowski and t. kaptur. 1984. the quality of the green fraction of leaf protein concentrate from chenopodium quinoa willd. grown at different levels of fertilizer nitrogen. anim. feed sci. technol. 11: 239-245. dost, m. 2015. field evaluation results across locations and identification of suitable quinoa varieties,” in wrap up workshop of regional quinoa project (tcp/rab/3403–fao) (rome: food and agriculture organization of the united nations). erley, g.s.a., h.p. kaul, m. kruse and w. aufhammer. 2005. yield and nitrogen utilization efficiency of the pseudocereals amaranth, quinoa and buckwheat under differing nitrogen fertilization. eur. j. agron. 22: 95-100. fawy, h.a., m.a. attia and r.h. hagab. 2017. effect of nitrogen fertilization and organic acids on grains productivity and biochemical contents of quinoa plant grown under soil conditions of ras sader-sinai. egyptian j. desert res. 67(1): 171-185. geren, h. 2015. effects of different nitrogen levels on the grain yield and some yield components of quinoa (chenopodium quinoa willd.) under mediterranean climatic conditions. turk. j. field crops 20: 59-64. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research 2nd edn. irri, los banos, languna, the philippines, pp.62-74. gomaa, e.f. 2013. effect of nitrogen, phosphorus and biofertilizers on quinoa plant (chenopodium quinoa). j. appl. sci. res. 9: 5210-5222. hirich, a. 2014. eff ects of deficit irrigation using treated wastewater and irrigation with saline water on legumes, corn and quinoa crops. ph.d., thesis, hassan ii institute of agronomy and veterinary medicine, morocco. hirich, a., r. choukr-allah and s.-e. jacobsen. 2013. the combined effect of deficit irrigation by treated wastewater and organic amendment on quinoa (chenopodium quinoa willd.) productivity. desalination water treat. 106, doi:10.1080/19443994.2013.777944. jacobsen, s.-e. and j.l. christiansen. 2016. some agronomic strategies for organic quinoa (chenopodium quinoa willd.). j. agro. crop sci. 202(6): 01-10, doi:10.1111/jac.12174. https://doi.org/10.1111/jac.12155 92 biswas et al. jacobsen, s.-e., i. jørgensen and o. stølen. 1994. cultivation of quinoa (chenopodium quinoa) under temperate climatic conditions in denmark. j. agric. sci. 122: 47-52. kansomjet, p., p. thobunluepop, s. lertmongkol, e. sarobol, p. kaewsuwan, p. junhaeng, n. pipattanawong and m.t. ivan. 2017. response of physiological characteristics, seed yield and seed quality of quinoa under difference of nitrogen fertilizer management. am. j. plant physiol. 12: 20-27. kaveeta, l., m. nanakorn, s. suwanwong and s. tantiwiwat. 2009. plant physiology. kasetsart university press, bangkok p.261. lavini, a., c. pulvento, r. d‟andria, m. riccardi, r. choukr-allah and o. belhabib. 2014. quinoa‟s potential in the mediterranean region. j. agron. crop sci. 200: 344–360. doi: 10.1111/jac.12069. oelke, e.a., d.h. putnam, t.m. teynor and e.s. oplinger. 1992. quinoa. alternative field crops manual. http://www.hort.pur due.edu/newcrop/afcm/quinoa.html. ramesh, k., k.b. suneetha devi, k.a. gopinath and k. praveen. 2019. geographical adaptation of quinoa in india and agro techniques for higher productivity of quinoa. j. pharma. phytochem. 8(3): 2930-2932. rao, n.k. and m. shahid. 2012. quinoa a promising new crop for the arabian peninsula. american-eurasian j. agric. environ. sci. 12(10): 1350-1355. repo-carrasco, r., c. espinoza and s.-e. jacobsen. 2003. nutritional value and use of the andean crops quinoa (chenopodium quinoa) and kañiwa (chenopodium pallidicaule). food rev. int. 19: 179–189. doi: 10.1081/fri120018884. sadia, a. 2018. influence of fertilizer levels on growth and yield of quinoa. ms thesis, department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh. schulte auf‟m erley, g., h.p. kaul, m. kruse and w. aufhammer. 2005. yield and nitrogen utilization efficiency of the pseudo cereals amaranth, quinoa and buckwheat under differing nitrogen fertilization. eur. j. agron. 22: 95-100. shams, a.s. 2011. response of quinoa to nitrogen fertilizer rates under sandy soil conditions. int j. water resour. arid environ. 1: 318–325. shams, a.s. 2012. response of quinoa to nitrogen fertilizer rates under sandy soil conditions. proceedings of the 13th international agronomy conference, september 9-10, 2012, benha university, egypt. pp.195-205. thanapornpoonpong, s. 2004. effect of nitrogen fertilizer on nitrogen assimilation and seed quality of amaranth (amaranthus spp.) and quinoa (chenopodium quinoa willd.). ph.d. thesis, georg august university of gottingen, phayao, thailand. weisany, w., y. raei, and k.h. allahverdipoor. 2013. role of some of mineral nutrients in biological nitrogen fixation. bull. env. pharmacol. life sci. 2(4): 77-84. bangladesh agron. j. 2023, 26(1): 32-39 effect of crop establishment method and fertilizer management on yield performance of boro rice (var. brri dhan28) in t. aman-mustard-boro rice cropping pattern m. l. k. khan1, m. a. ali2 and s. k. paul1* 1department of agronomy, bangladesh agricultural university, mymensingh 2202, bangladesh 2on farm research division, bangladesh agricultural research institute, joydebpur, gazipur, bangladesh *corresponding author, email: skpaul@bau.edu.bd (received: 4 june 2023, accepted: 11 september 2023) keywords: conservation agriculture, fertilization, benefit cost ratio abstract the study was carried out at the salpoborian village under sadr papilla of mymensingh from february to june 2014 to assess the effect of crop establishment method and fertilizer management on the yield performance of boro rice (var. brri dhan28) in t. aman-mustardboro rice cropping pattern. the experiment comprised three crop establishment methods viz. traditional puddled-transplanting (tpt), unpuddled-one pass in dry condition (udc), unpuddled-zero tillage (uzt) and five levels of fertilizers viz., 100-60-40-60-10 n-p-k-s-zn kg ha-1 at recommended (rd) dose (f1), n-k-s-zn at rd plus 50% p (f2), n-p-s-zn at rd plus 50% k (f3), p-k-s-zn at rd plus 75% n as guti urea (2.7 g/4 hills) (f4), p-k-s-zn at rd plus 75% n as pilled urea (f5). the experiment was laid out in a split -plot design with 4 replications with crop establishment method in the mainplots and fertilizer management in the sub-plots. grain yield was not significantly influenced by crop establishment method, fertilizer management and their interactions. however, numerically the maximum grain yield of 3.19 t ha−1 was found in both unpuddled-one pass in dry condition (udc) and unpuddled-zero tillage (uzt) with 3.32 t ha−1 in p-k-s-zn at rd plus 75% n as pilled urea (f5) and 3.47 t ha−1 in unpuddled-one pass in dry condition with p-k-s-zn at rd plus 75% n as pilled urea and traditional puddled-transplanting with p-k-s-zn at rd plus 75% n as pilled urea. similar higher gross margin (tk. 26629 and tk. 27428) and benefit cost ratio (1.61 and 1.60) was also observed in uzt × f4 and udc × f5, respectively. so, it can be concluded that unpuddled-zero tillage with p-k-s-zn at rd plus 75% n as guti urea (uzt × f4) and unpuddled-one pass in dry condition with p-k-s-zn at rd plus 75% n as prilled urea (udc × f5) is the beneficial technique for boro rice (var. brri dhan28) cultivation in t. aman-mustard-boro rice cropping pattern. introduction about 72.31% of total cropped area of bangladesh is used for rice production, with annual production of 36.60 million tons from 11.42 million ha of land (bbs, 2020). rice crop area is decreasing day by day due to high population pressure. in our country, the dominant cropping pattern, t. aman (wet season rice) -fallow-boro (dry season rice) plays an important role which covers about 1.8 million ha (about 22% of the total land) of land. bangladesh agricultural research institute (bari) developed high yielding yellow seeded mustard (brassica campestris) varieties, bari sarisha14 and bari sarisha15 recommended for t. aman-mustard-boro rice cropping pattern. increasing demand for the rice-mustard-rice cropping system led to the innovation of alternative crop establishment method and fertilizer application for boro rice. different crop establishment methods are generally followed in the field. among them zero and minimum tillage crop establishment methods have some advantages like time, labor, low plough and water cost over traditional puddle system. different types of agricultural tools are used in farming for initial land preparation which among the crop production factors contributes up to crop establishment method and fertilizer management on yield performance of boro rice 33 20% (khurshid et al., 2006). during such cultivation, sub-soil compaction is usually caused by tillage system specifically through mechanical practices. repeated ploughing may result in plough pan formation in cultivated soil due to use of heavyweight tillage machineries. plough pans are formed in the same profile under power tiller and country plough treatment mostly in rice field (islam et al., 2005). puddling is advantageous for rice cultivation but imposes limitations for upland crops. under the conventional tillage system, a plough pan layer is developed that may impose changes in soil physical properties and may lead to a decrease in soil physical quality (bertolino et al., 2010). adoption of minimum tillage and non-puddled transplanting might be an alternative to puddled transplanting to overcome negative impacts such as excess water requirement, formation of hardpan, soil fertility deterioration etc. (sayre and hobbs, 2004; singh et al., 2014). this technology has possible to allow saving in labor, energy, water and time during rice establishment as well as improving soil fertility (islam et al., 2012). among the production factors affecting crop yield, fertilizer is the single most important factor that plays a dominant role in yield increase if other production factors are not limiting. an increasing in the yield of rice by 70-80% may be obtained from proper application of n fertilizer (ifc, 1982). the efficiency of nitrogen use by rice plant is very low, the recovery of being only 30-50% (de datta and crasswell, 1982). phosphorus influences the flowering, photosynthesis, nfixation, ripenning and quality of rice. potassium in rice plays an effective role in root development and ripenning and impacts resistance to diseases (tisdale and nelson, 1996). application of potassium in appropriate rate and time helps spikelets formation or grain of rice (zheng et al.,1995). brri dhan28 is a highly yield potential variety with life cycle of 135-140 days. so, the present study is to examine the response of this variety to application of different rates of n, p, k, s and zn fertilizers in different crop establishment method. materials and methods experimental site the experiment was carried out at the farmers field, swalpobarian (24.7960 n latitude and 90.3130 e longitude) khagdahar, mymensingh, during the boro season of 2014 (february-june) to assess the effect of crop establishment method and fertilizer management on the performence of boro rice. the experimental area belongs to the non-calcareous dark grey soil under agro-ecological zone of the old brahmaputra floodplain (aez-9) (undp and fao, 1988). the land was medium high and the soil was silty loam and well drained and its general fertility level is low. experimental treatments and design the experiment comprised three rice establishment methods viz. traditional puddled (double tillage with laddering) transplanting (tpt), unpuddled-one pass in dry condition (udc), unpuddled-zero tillage (uzt) and five fertilizer managements viz. 100-60-4060-10 kg n-p-k-szn ha−1 as recommended (rd) dose (f1), n-k-s-zn at rd plus 50% p (f2), n-p-s-zn at rd plus 50% k (f3), p-k-s-zn at rd plus 75% n as guti urea (2.7g usg/ 4 hill) (f4), p-k-s-zn at rd plus 75% n as prilled urea (f5). the experiment was laid out in a splitplot design with 4 replications where plant establishment methods in the mainplots and fertilizer management in the sub-plots. each plot size was 80 m2 (10.0 m8.0 m). crop husbandry after harvest of mustard, the experimental field was prepared as per treatment protocol. traditional puddled transplantingland was puddled with 2 tillages’ followed by laddering for land leveling. unpuddled transplanting-land was prepared with single pass in dry condition with no laddering and submergence in water for two days, then direct transplant the seedling on third day. 34 khan et al. unpuddled-zero tillage with no laddering, and submergence the land in water for two days, and then direct transplant the seedling on third day. weeds and stubble of the previous crop were collected and removed by hand from the field. the land was prepared finally 24 february 2014. about 50-day-old seedlings were uprooted carefully from the nursery bed. before uprooting the seedlings, nursery beds were slightly irrigated for easier uprooting. uprooted seedlings were transplanted in the unit plots on 25 february 2014 at the rate of two seedling hill−1 maintaining spacing 20 cm15 cm. the experimental plots were fertilized as per the fertilizer treatment. the fertilizer n, p, k, s and zn was applied @ 100, 60, 40, 60 and 10 kg ha−1 in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum and zinc sulphate, respectively. the entire amounts of triple super phosphate, half of muriate of potash, gypsum and zinc sulphate were applied as basal dose at final land preparation. urea was applied at three splits in the form of prilled urea and one split in the form of urea super granule (usg). urea was top-dressed in three equal installments. the first and second splits were top dressed at 15 dat (after seedling recovery) and maximum tillering stage (30 dat), respectively. urea super granule (usg) was applied at the centre of four hills in every alternate row by guti urea applicator at 15 dat (days after transplanting). the third split of urea and half of mop were applied before the panicle initiation stage (45 dat). three weeding were done by hand pulling as necessary to keep the plots weed-free. weeding was done at 25, 35 and 45 dat, respectively. experimental plots were irrigated as and when necessary to enhance tillering and weed control. flood irrigation was given to maintain a level of standing water 2-4 cm till the maximum tillering stage and after that, a water level of 4-5 cm was maintained up to grain filling stage. excess water was drained out from the plots 15 days before the harvest. no chemical was used to protect the plant. but parching was used to allow birds for pest control. a logo system (every ten lines after one row gap was maintained) was followed in every plot for proper aeration and naturally minimize the insect and pest. the bunds around individual plots were repaired as and when necessary, so that water did not move between the plots. data collection the crop was harvested at full maturity when about 90% of the seeds become golden yellow in color. the crops were harvested on 11 may 2014. the harvested crop of each plot was separately bundled and threshed by pedal thresher. grains were sun-dried and cleaned properly. moisture was adjusted at 14% moisture during weight. straws were also sun dried properly. finally grain and straw yields converted to t ha−1. statistical analysis data were compiled and tabulated in proper form for statistical analysis. the recorded data on different parameters were analyzed with the help of computer package cropstat 7.2. the mean differences among the treatments were tested with duncan’s multiple range test (gomez and gomez, 1984). results and discussion plant height, total tillers hill−1 and non-effective tillers hill−1were significantly influenced by crop establishment method (figure 1, 2 and table 1). the maximum plant height (83.10 cm) was obtained from tpt, followed by unpuddled-one pass in udc and the shortest plant (78.95 cm) from uzt. it is observed that the decreasing number of tillages found to produce a negative effect on plant height (figure 1). crop establishment method and fertilizer management on yield performance of boro rice 35 . fig. 1. the plant height of boro rice (cv. brri dhan28) as influenced by different crop establishment method (p<0.05). tpt: traditional puddled-transplanting, udc: unpuddled-dry cultivation, uzt: unpuddled-zero tillage]. fig. 2. number of total tillers hill−1 of boro rice as influenced by different crop establishment method (p<0.05). tpt: traditional puddled-transplanting, udc: unpuddled-one pass in dry condition, uzt: unpuddled-zero tillage. table 1. effect of crop establish method on the crop characters, yield components and yield of boro rice (cv. brri dhan28) crop establishment method effective tillers hill−1 (no.) non effective tillers hill-1 (no.) panicle m−2 (no.) panicle length (cm) grains panicle−1 (no.) sterile spikelets panicle−1 (no.) 1000 grain weight (g) grain yield (t ha−1) straw yield (t ha−1) harvest index (%) tpt 12.02 1.88a 286.05 21.26a 115.12 6.01 22.24 3.18 2.99 51.54a udc 12.47 1.64b 288.50 21.39a 117.57 5.34 22.32 3.19 2.98 51.69a uzt 12.78 1.83a 284.75 20.87b 115.06 5.41 21.77 3.19 3.12 50.49b level of significance ns * ns * ns ns ns ns ns * cv (%) 19.1 6.0 3.7 3.2 5.2 18.2 3.5 12.0 12.9 2.8 tpt = traditional puddled-transplanting, udc= unpuddled-one pass in dry condition, uzt= unpuddled-zero tillage. * = significant at 5% level of probability, ns = not significant 36 khan et al. the maximum number of total tillers hill−1 (14.62) was obtained from uzt which was at par with udc and the lowest one (13.90) was counted from tpt (figure 2). a similar result on number of total tillers hill−1 due to crop establishment method has also been reported by hobbs et al. (1997). the maximum number of non-effective tillers hill−1 (1.88) was found from tpt which was at par with uzt and the lowest (1.64) was found from udc. crop establishment method was not significantly influenced the number of effective tillers hill−1 and panicles m−2 (table 1). numerically the highest number of effective tillers hill-1 (12.78) and maximum number of panicle m−2 (288.50) were found from uzt and udc, respectively. the length of panicle was significantly influenced by the crop establishment method (table 1). the maximum panicle length (21.39 cm) was obtained from udc which was statistically identical with tpt and the shortest panicle (20.87 cm) from uzt. grains panicle−1, sterile spikelets panicle−1, 1000-grain weight, grain yield and straw yield were not significantly influenced by crop established method. numerically, higher grain yield (3.19 t ha−1) was found in both udc and uzt crop establishment system compare to tpt system. the highest harvest index (51.69%) was found in udc which was at par with tpt and the lowest one (50.49 (3.19 t ha−1) was found in uzt. plant height was significantly affected by the effect of fertilizer management. the maximum t plant (83.25 cm) was obtained from f1 which was at par with f2, f3, and f5 (figure 3). the shortest plant height (78.25 cm) was obtained in f4. here, it is observed that reduced fertilizer dose found to produce a negative effect on plant height (figure 3). similar result on plant height due to fertilizer doses have also been reported in previous studies (singh et al., 2006; paul et al., 2020 and paul et al., 2021), who noticed that higher fertilizer application significantly increased plant height. the other crop characters, yield components and yield were not significantly influenced by fertilizer management (table 2). numerically grain yield (3.32 t ha-1), straw yield (3.15 t ha-1) and harvest index (51.35%) were found when fertilized with f5 (table 2). fig. 3. the plant height of boro rice as influenced by fertilizer management (p<0.05). f1: n, p, k, s, zn at recommended (rd) dose, f2: n, k, s, zn at rd plus 50% p, f3: n, p, s, zn at rd plus 50% k, f4: p, k, s, zn at rd plus 75% n as guti urea, f5: p, k, s, zn at rd plus 75% n as prilled urea. crop establishment method and fertilizer management on yield performance of boro rice 37 table 2. effect of fertilizer management on the crop characters, yield components and yield of boro rice (cv. brri dhan28) crop establishment method effective tillers hill−1 (no.) non-effective tillers hill−1 (no.) total tillers hill−1 (no.) panicles m−2 (no.) panicle length (cm) grains panicle−1 (no.) sterile spikelets panicle−1 (no.) 1000-grain weight (g) grain yield (t ha−1) straw yield (t ha−1) harvest index (%) f1 12.39 1.88 14.28 286.16 21.24 115.20 5.46 22.10 3.07 2.91 51.35 f2 12.14 1.71 13.86 282.50 20.84 113.54 5.71 21.90 3.08 2.94 51.22 f3 12.95 1.80 14.76 287.08 21.22 117.20 6.23 22.08 3.25 3.12 50.92 f4 12.25 1.90 14.15 288.16 21.45 119.48 4.98 22.24 3.21 3.05 51.32 f5 12.38 1.63 14.02 288.25 21.12 114.16 5.56 22.23 3.32 3.15 51.37 level of significance ns ns ns ns ns ns ns ns ns ns ns cv (%) 6.0 19.1 6.0 3.7 3.2 5.2 18.2 3.5 12.0 12.9 2.8 f1= n, p, k, s, and zn at recommended (rd) dose, f2= n, k, s, and zn at rd plus 50% p, f3 = n, p, s, and zn at rd plus 50% k, f4 = p, k, s, and zn at rd plus 75% n as guti urea, f5 = p, k, s, and zn at rd plus 75% n as prilled urea. ns= not significant table 3. effect of interaction between crop establish method and fertilizer management on the crop characters, yield components and yield of boro rice (cv. brri dhan28) crop establishment method plant height (cm) effective tillers hill−1 (no.) noneffective tillers hill−1 (no.) total tillers hill−1 (no.) panicles m−2 (no.) panicle length (cm) grains panicle-1 (no.) sterile spikelets panicle−1 (no.) 1000grain weight (g) grain yield (t ha−1) straw yield (t ha−1) harvest index (%) tpt ×× f1 84.50 12.07 1.91 13.98 286.50 20.98 115.53a 5.54a 22.10 3.00 2.83 51.48 tpt ×× f2 84.25 12.28 1.91 14.20 281.00 20.91 110.65b 5.66a 22.16 3.08 2.92 51.47 tpt ×× f3 84.25 12.28 1.66 13.95 287.50 20.91 121.17a 6.55a 22.21 3.21 3.01 51.51 tpt × f4 80.00 11.59 2.04 13.63 287.50 21.66 121.16a 5.83a 22.37 3.16 2.97 51.56 tpt ×× f5 82.50 11.87 1.88 13.75 287.75 21.83 107.08b 6.47a 22.36 3.47 3.25 51.68 udc ×× f1 84.25 12.37 1.70 14.07 287.00 21.66 115.31a 5.21b 22.65 3.01 2.77 52.12 udc ×× f2 86.00 12.24 1.58 13.82 287.00 21.20 114.65a 6.97a 22.21 3.08 2.92 51.47 udc ×× f3 81.25 13.08 1.71 14.79 287.00 21.58 120.12a 5.93a 22.37 3.25 3.03 51.60 udc ×× f4 76.00 12.45 1.87 14.32 288.50 21.58 116.74a 3.60c 22.36 3.13 2.95 51.56 udc ×× f5 81.50 12.20 1.37 13.57 293.00 20.95 121.01a 5.00b 22.05 3.47 3.25 51.68 uzt ×× f1 81.00 12.74 2.03 14.78 285.00 21.08 114.76a 5.64a 21.56 3.21 3.15 50.46 uzt ×× f2 78.00 11.91 1.63 13.57 279.50 20.40 115.31a 4.51b 21.34 3.08 2.98 50.74 uzt ×× f3 78.00 13.49 2.03 15.53 286.75 21.16 110.32b 6.20a 21.65 3.28 3.32 49.64 uzt ×× f4 78.75 12.70 1.78 14.49 288.50 21.12 120.53a 5.51b 22.00 3.33 3.22 50.85 uzt ×× f5 79.00 13.08 1.66 14.74 284.00 20.58 114.40a 5.22b 22.30 3.03 2.95 51.48 level of significance ns ns ns ns ns ns 8.69 * ns ns ns 51.47 cv (%) 3.7 6.0 19.1 6.0 3.7 3.2 5.2 18.2 3.5 12.0 12.9 51.56 tpt = traditional puddled-transplanting, udc= unpuddled-one pass in dry condition, uzt= unpuddled-zero tillage; f1= n, p, k, s, and zn at recommended (rd) dose, f2= n, k, s, and zn at rd plus 50% p, f3 = n, p, s, and zn at rd plus 50% k; f4 = p, k, s, and zn at rd plus 75% n as guti urea, f5 = p, k, s, and zn at rd plus 75% n as prilled urea. * = significant at 5% level of probability, ns= not significant 38 khan et al. the number of grains panicle−1, sterile spikelets panicle−1 and the crop characters and yield components and yield were not significantly influenced by the interaction between crop establishment method and fertilizer management (table 3). apparently, the highest grain yield (3.47 t ha−1) was obtained from udc × f5 and tpt ××f5 and the lowest grain yield (3.00 t ha-1) from tpt ×× f1 where numerically the highest straw yield (3.32 t ha−1) from uzt×f3 (table 3). the highest number of panicle m−2 (293) in udc× f5 and higher number total tillers hill−1 in uzt ×× f3 might be responsible for higher grain and straw yields udc × f5 and uzt× f3, respectively. economic analysis the highest variable cost (tk. 49374 ha−1) was obtained from tpt×f1 because all variable costs were considered in calculation. while the lowest variable cost (43337 bdt ha−1) from uzt ×× f2 (table 4). table 4. economic performance of boro rice under crop establishment method and fertilizer management crop establishment method ×× fertilizer management variable cost (tk. ha−1) gross return (tk. ha−1) gross margin (tk. ha−1) benefit-cost ratio (bcr) tpt ×× f1 49374 63297 13923 1.28 tpt ×× f2 47872 65189 17316 1.36 tpt ×× f3 48360 67665 19305 1.39 tpt × ×f4 48516 65734 17218 1.35 tpt ×× f5 48126 73281 25155 1.52 udc ×× f1 47101 63063 15962 1.34 udc ×× f2 45599 65189 19590 1.43 udc ×× f3 46087 67646 21559 1.47 udc ×× f4 46243 65637 19394 1.42 udc ×× f5 45853 73281 27428 1.60 uzt ×× f1 44839 67938 23099 1.51 uzt ×× f2 43337 65150 21813 1.50 uzt ×× f3 43825 67041 23216 1.53 uzt ×× f4 43981 70610 26629 1.61 uzt ×× f5 43669 64331 20662 1.47 the highest gross return (73281 tk. ha−1) was found in tpt ×× f5 and udc ××f5. the lowest gross return (tk. 63063 ha−1) was obtained from udc × f1. the highest gross margin (27428 bdt ha−1) was found udc × f5 followed by uzt ×× f4 (table 4). the higher benefit-cost ratio 1.61 and 1.60 obtained from uzt × f4 and udc × f5, respectively. this might be possibly due to higher gross return and low variable cost of unpuddled crop establishment method and reduced n dose used. so, it can be concluded that unpuddled-zero tillage with p, k, s, and zn at rd plus 75% n as guti urea (uzt × f4) and unpuddled-one pass in dry condition with p, k, s, and zn at rd plus 75% n as prilled urea (udc × f5) could be the beneficial for boro rice (var. brri dhan28) cultivation in t. aman-mustard-boro rice cropping pattern. conclusion from the results of the study, it can be concluded that unpuddled-one pass dry cultivation (udc) with p, k, s, zn at rd plus 75% n as prilled urea (udc ×× f5) could be the suitable technique for boro rice (var. brri dhan28) cultivation in t. aman-mustard-boro rice cropping pattern. crop establishment method and fertilizer management on yield performance of boro rice 39 acknowledgements the authors thankfully acknowledge to international rice research institute (irri) for partial financial support to conduct the study. references bbs (bangladesh bureau of statistics), 2020. statistical yearbook of bangladesh statistics division, ministry of planning, govt. of the people’s republic of bangladesh. pp. 125-144. bertolino, a.v.f.a., n.f. fernandes, j.p.l., miranda, a.p., souza, m.r.s. lopes and f. palmieri. 2010. effects of plough pan development on surface hydrology and on soil physical properties in southeastern brazilian plateau. j. hydrol. 393 (1–2): 94-104. de datta, s.k. and e.t. creswell. 1982. nitrogen fertility and management in wetland rice soils. in: rice research strategies for the future, c.c. gray iii, f.e. marcos, and n.c. brady (eds.). los baños, philippines: international rice research institute. pp. 283–316. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. john wiely and sons. new york. pp. 97-129. hobbs, p.r., g.s. giri and p. grace. 1997. reduced and zero tillage options for the establishment of wheat after rice in south asia. rice-wheat consortium for the indo-gangetic plains and cimmyt (rwc paper no. 2). ifc. 1982. fso/faic working parts on the economics of fertilizers. international fertilizer correspondent. 23(1): 7-10. islam, a.k.m.s., m.m. hossain, m.a. saleque, m.a. rahman, b. karmakar, and m.e. haque. 2012. effect of minimum tillage on soil properties, crop growth and yield of aman rice in drought prone northwest bangladesh. bangladesh agron. j. 15(1): 43-51. islam, m.s., a.s.m.s. karim, m.s. hossain and m.m. masud. 2005. tillage and mulch effects on some soil physical properties and yield of wheat in shallow red brown terrace soils of bangladesh. sarhad j. agric. 21(4): 655-665. khurshid, k., m. iqbal, m.s. arif and a. nawaz. 2006. effect of tillage and mulch on soil physical properties and growth of maize. int. j. agric. biol. 8: 593–596. paul, n.c., s.k. paul, m.a. salam and s.c. paul. 2021. dry matter partitioning, yield and grain protein content of fine aromatic boro rice (cv. brri dhan50) in response to nitrogen and potassium fertilization. bangladesh j. bot. 50(1): 103-111. paul, s.k., n.y. nila and m.a.r. sarkar. 2020. grain yield and quality of aromatic boro rice (cv. brri dhan50) subject to date of transplanting and nutrient management. thai j. agric. sci. 53(2): 85-96. sayre, k.d. and p. hobbs. 2004. the raised-bed system of cultivation for irrigated production conditions. in: sustainable agriculture and the intonational rice-wheat system, r. lal., p.r. hobbs., u. norman and d.o. hansen (eds.). crc press, boca raton. p. 337-355. singh, a., r. kumar and j.s. kang. 2014. tillage system, crop residues and nitrogen to improve the productivity of direct seeded rice and transplanted rice. current agric. res. j. 2(1): 14-29. singh, r.p., p.k. yadav, r.k. singh, m.k singh and j. singh. 2006. effect of chemical fertilizer, fym and biofertilizer on performance of rice and soil properties. crop res. 32: 283-285. tisdale, s.l. and n.l. nelson. 1996. soil fertility and fertilizer. 2nd edn. mc.millan, new york. 10022. pp. 71-110. undp and fao. 1988. land resources appraisal of bangladesh for agricultural development. report 2. agro-ecological regions of bangladesh fao, undp, rome. pp. 116. zheng, z.s., x.h., liu, j.x., wu, x.g., zhu, s.f. zhang and x.g. wang. 1995. the effects of different fertilizer application methods and plant densities on yield and quality of rice. acta agric. shanghai. 11(3): 81-86. bangladesh agron. j. 2019, 22(2): 139-150 growth performance of lentil by the effect of irrigation and boron splitting asfoliar application s. paul1, t.s. roy2, r. chakraborty3, m. roy4 and s.c. sarker5* 1ms student, 2professor, 3lecturer, 5assistant professor, department of agronomy, sher-e-bangla agricultural university, dhaka 1207. 4ms student, department of agroforestry and environmental science, sher-e-bangla agricultural university, dhaka -1207. corresponding e-mail: shimul@sau.edu.bd (received: 08 march 2020, accepted: 29 april 2020) key words: boron, irrigation, foliar application, splitting abstract a field experiment was conducted for evaluating the effect of irrigation and boron splitting as foliar spray on growth and yield of lentil at the research field of the department of agronomy, sher-e-bangla agricultural university, dhaka from november, 2018 to march, 2019.three levels of irrigation viz., i0: control, i1: one irrigation at 25 days after sowing (das), i2: two irrigations at 25 das and 40 das and boron was applied by four levels viz., b0: control, b1: 80% recommended dose as basal + rest 20% as foliar spray (fs) at pre-flowering (pf), b2: 60% rd as basal + rest 40% as fs at pf, b3: 40% rd as basal + rest 60% as fs at pf. the experiment was fully set up in a split-plot design with three replications. two irrigations at 25 and 40 das result produced that the highest plant length, branches plant-1, leaves plant-1, dry weight plant-1. on the other hand, b3 (40% rd as basal + rest 60% as fs at pf) produced significantly the highest growth of lentil. result also showed that the highest plant length (27.59 cm), number of branches (5.73) and plant dry matter (4.83 g) recorded from i2b3 combinations. therefore, the combination of two irrigations at 25 and 40 das and boron at 40% rd as basal + rest 60% as foliar spray at pre-flowering might be considered as effective dose for the cultivation of lentil in bangladesh. introduction legumes are considered the world's most essential food source after cereals, as they are the main protein and energy sources for humans. it is cultivated in an area of 898 million ha in bangladesh with 389 million tons of output and 434 kgha-1of productivity (bbs, 2018). according to the recommendation of the fao (2013), a minimum pulse intake per capita should be 80 g per day, whereas in bangladesh it is only 17.92 g per day. it belongs to the papilionaceae sub family under the leguminosae. seed contains 25% protein, 1.1% fat and 59% carbohydrate. a significant amount of vitamin a and b is also provided by lentil. totally in bangladesh, 176,633 metric tons of lentil from an area of 385399 million hectares were produced during 2017-2018 (bbs, 2018). soil is the major factor in many parts of the world which limits crop production. plant physiological processes for example photosynthesis, cellular growth and turgidity, etc. are directly or indirectly influenced by irrigation (reddi and reddi, 1995). siliquae per plant, seed and oil yield decreased with higher water pressure (rahnema and bakhshandeh, 2006).inadequate water supply in growing stage, may decrease quantity and quality of crop (debaeke and aboudrare, 2004). in contrary, nutrient leaching, reduced crop production and wastage of water are also reported (pang et al., 1997; sezen et al., 2006). foliar application of nutrients can increase the use of nutrients and reduce pollution by lowering the amount of fertilizer applied to the soil directly (abdo, 2001). boron is an addictive substance in the growth, development and quality of plants (pilbeam and kirkby, 1983; marschner, 1995; brown et al., 1999; dordas et al., 2007). boron also plays a crucial role in sugar exchange, nitrogen fixation, protein 150 paul et al. synthesis, sucrose synthesis, cell wall formation, membrane stability and k+ movement (singh et al., 2014). boron deficiency results in plant sterility due to reproductive tissue malformation that affects pollen germination, leading to increased flower fall and decreased fruit area (subasinghe et al., 2003). considering the above facts, the present work was carried out to examine the effect of irrigation and boron levels on the growth of lentil. materials and methods the experiment was conducted at the agronomy research field, sher-e-bangla agricultural university, dhaka-1207 during the period from november, 2018 to march, 2019. the research field soil is slightly acidic with a low content of organic matter. before sowing, lentil var. bari mushur 6 seeds were tested for germination (over 90%). the experiment was set up in november in a split-plot design where accommodated irrigation treatments viz. control (i0), one irrigation (i1) at 25 days after sowing (das), two irrigations (i2) at 25 and 40 das in main plot and boron levels viz. b0 = 0 kg b/ha (control), b1=80% recommended dose of b as basal + rest 20% as foliar spray (bf) at pre-flowering (pf), b2 = 60% rd of b as basal + rest 40% as fs at pf, b3= 40% rd of b as basal + rest 60% as fs at pf in sub-plot. the size of the each unit plot was 2.5m 1.5m. the distance maintained between two blocks and plots were 0.5m and 0.3m, plant to plant distance 6cm. the land was fertilized with urea-tsp, mop-boric acid @ 50-90-40-8.5 kg ha-1. total urea, tsp and mop were applied as basal dose. boron was applied as boric acid as basal dose and rest amount were applied as foliar application at before flowering stage. the seeds were treated with autostin® 50 wdg (carbendazim group) before sowing the seeds to control the seed borne diseases. the seeds were sown in rows in the furrows having a depth of 2-3 cm. row to row distance was 30 cm. irrigation was applied in the experiment field at two times (25 days after sowing and 40 days after sowing). first irrigation was applied at vegetative stage and second irrigation at flowering stage. data recorded on growth parameters were recorded. the data was analyzed using a computer operated program mstat-10 and treatments means were estimated by the estimated by the duncan multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). results and discussion plant height effect of irrigation the plant height of lentil was highly influenced by irrigation(figure 1). resultsshowed that the highest plant height (15.91, 22.38, 25.22 and 24.72 cm at 35, 50, 65 das and at harvest respectively) was obtained from i2 (25 das and 40 days after sowing) followed by i1 (25 das) level of irrigation. similarly, the shortest plant height (12.84, 19.35, 21.55 and 22.09 cm at 35, 50, 65 das and at harvest) was recorded from i0 (no irrigation). results revealed that plant height increased with increasing irrigation levels irrespective of growing period up to at harvest. latif (2006), piri et al. (2011) and hosseiniet al. (2011) have found similar results when applying two irrigations during branching and pod development stage. growth performance of lentil by the effect of irrigation 149 i0 =no irrigation, i1= irrigation at 25 das, i2 = irrigation at 25 and 40 das fig.1. response of irrigation on plant height of lentil at different days aftersowing (se =1.0735, 0.6354, 0.5148, 0.503 at 35, 50, 65 das and at harvestrespectively). effect of boron lentil plant height also differed considerably due to different treatments of boron on different days after sowing (figure2). result showed that the highest plant height (16.98, 22.12, 24.39 and 23.97 cm at 35, 50, 65 das and at harvest, was obtained from b3 (40% recommended dose as basal + rest 60% as flower spray at pre-flowering) followed by b2 (60% rd as basal + rest 40% as fs at pf) and b1 (80% rd as basal + rest 20% as fs at pf) and without boron produced the lowest plant height (13.06, 20.05, 23.24, 23.14 cm at 35, 50, 65 das at harvest) respectively was obtained from b0 (control). comparable results was additionally found by vimalan et al. (2017). it seemed that 1.5 kg b ha-1 vastly increased plant height and control (b0) had the lowest quality of plant height in lentil. b0 = control; b1 = 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf fig.2. response of boron on plant height of lentil at different days after sowing (se= 0.6906, 0.8538, 0.9341, 0.9525 at 35, 50, 65 das and at harvest respectively). 0 5 10 15 20 25 30 35 das 50 das 65 das at harvest pl an t h ei gh t ( cm ) days after sowing i₀ i₁ i₂ 0 5 10 15 20 25 30 35 das 50 das 65 das at harvest pl an t h ei gh t ( cm ) days after sowing b₀ b₁ b₂ b₃ 150 paul et al. interaction effect of irrigation and boron interaction effect of different levels of irrigation and boron application in terms of plant height also exposed significant variation at different days after sowing (table 1). result indicated that the highest plant height (19.74, 22.54, 27.02 and 25.59 cm at 35, 50, 65 das and at harvest) was recorded from i2b3. correspondingly, the lowest plant height (12.71, 19.44, 23.99 and 23.30 cm at 35, 50, 65 days after sowing and control) had the lowest plant height in lentil and at harvest respectively was recorded from i0b0 which was statistically similar to i0b1 and i0b2. table 1. interaction effect ofirrigation and boron on plant height of lentil atdifferent days after sowing treatment combinations plant height (cm) at 35 das 50 das 65 das at harvest i0b0 12.71 bc 19.44 ab 23.99 a-d 23.30 i0b1 11.53 c 18.07 b 19.81d 21.38 i0b2 13.28 bc 20.17 ab 21.12 cd 21.56 i0b3 13.84 bc 20.23 ab 21.28 cd 22.11 i1b0 14.49 bc 21.66 ab 23.54 a-d 24.50 i1b1 15.31 a-c 21.35 ab 24.12 a-d 25.34 i1b2 15.57a-c 19.66 ab 24.26 a-d 24.40 i1b3 17.37 ab 21.72 ab 24.88 a-c 24.21 i2b0 11.98 c 19.57 ab 22.20 b-d 22.95 i2b1 15.05 bc 23.45 a 25.10 a-c 25.85 i2b2 16.88 ab 22.10 ab 26.55 ab 26.56 i2b3 19.74 a 22.54 ab 27.02 a 27.59 se 1.1962 1.4789 1.6179 ns cv (%) 13.98 12.3 11.85 12 ns = non-significant;i0 =no irrigation; i1= 25 das; i2 = 25 das and 40 das, b0= control; b1= 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf number of leaves plant-1 effect of irrigation the number of leaves plant-1differed considerably due to different treatments of irrigations on different days after the planting. (figure3). the greatest number of leaves plant-1 was obtained at different stages of growth (14.23, 24.35, 52.58 and 48.88 at 35, 50, 65 das and at harvest) from i2 (25 days after sowing and 40 das).the lowest number leaves plant-1 (14.44, 24.99, 37.54 and 36.65 at 35, 50, 65 das and at harvest) was obtained from i0 (control). growth performance of lentil by the effect of irrigation i0 = no irrigation, i1 = 25 das, i fig. 3. response of irrigation on number of leaves plant 0.3887, 1.3164, 7.9574, 4.475 at 35, 50, 65 das and at harvest respectively) effect of born boron had a major effect on the number of leaves plant number of leaves plant-1 (15.08, 27.37, 53.63 and 43.81 at 35, 50, 65 das and at harvest respectively) was obtained from b3 (40% recommended dose as basal + rest which was statistically different with b2 (60% rd as basal + rest 40% as fs at pf) and b basal + rest 20% as fs at pf) and without boron produce the lower number of leaves plant 23.11, 40.89 and 44.43 at 35, 50, 65 das and at harvest) was recorded from b b0 = control; b1 = 80% recommended dose as basal + rest 20% as foliar spray at pre basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs a fig. 4. response of boron on number of leaves plant (se=0.5633, 1.4268, 7.1379, 7.3402 at 35, 50, 65 das and at harvest respectively) 0 10 20 30 40 50 60 35 das 50 das n um be r o f l ea ve s p la nt -1 0 10 20 30 40 50 60 35 das 50 das n um be r o f l ea ve s p la nt -1 days after sowing f irrigation 149 = 25 das, i2 = 25 & 40 das number of leaves plant-1 of lentil at different dayafter sowing(se= 0.3887, 1.3164, 7.9574, 4.475 at 35, 50, 65 das and at harvest respectively). had a major effect on the number of leaves plant-1 (figure4). result showed that the highest (15.08, 27.37, 53.63 and 43.81 at 35, 50, 65 das and at harvest respectively) (40% recommended dose as basal + rest 60% as foliar spray at pre-flowering) (60% rd as basal + rest 40% as fs at pf) and b1 (80% rd as basal + rest 20% as fs at pf) and without boron produce the lower number of leaves plant-1(13.41, 44.43 at 35, 50, 65 das and at harvest) was recorded from b0 (control). = 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as = 40% rd as basal + rest 60% as fs at pf response of boron on number of leaves plant-1 of lentil at different days after sowing (se=0.5633, 1.4268, 7.1379, 7.3402 at 35, 50, 65 das and at harvest respectively). 65 das at harvest days after sowing i₀ i₁ i₂ 65 das at harvest days after sowing b₀ b₁ b₂ b₃ 150 paul et al. interaction effect of irrigation and boron interaction effect of different levels of irrigation and boron application in terms of leaves plant-1 also exposed significant variation at different days after sowing (table 2). the highest number of leaves plant-1 (45.19, 53.22 and 55.23 at 50, 65 das and at harvest) was produced from the interaction of i2b3. the lowest number of leaves plant-1 was produced from the interaction of i0b0 (control) which was statistically similar with i0b1, i0b2, i0b3, i1b0, i1b1 and i1b3 combinations. table 2. interaction effect of irrigation and boron on the number of leaves plant-1 of lentilat different days after sowing treatment combinations number of leaves plant-1 at 35 das 50 das 65 das at harvest i0b0 14.00 24.89 c 34.44 ab 33.44 i0b1 14.00 24.73 c 36.78 ab 35.44 i0b2 14.78 25.21 c 34.49 ab 37.02 i0b3 15.00 25.14 bc 34.67 ab 35.70 i1b0 13.56 24.22 bc 41.67 ab 42.33 i1b1 13.70 23.22 bc 43.89 ab 44.89 i1b2 14.81 25.55 ab 44.44 ab 49.44 i1b3 14.78 31.78 a 43.00 ab 40.13 i2b0 12.67 20.22 bc 36.55 ab 36.52 i2b1 13.33 21.45 bc 32.33 b 36.14 i2b2 24.43 42.56 d 48.22 ab 46.96 i2b3 25.46 45.19 d 53.22 ab 55.23 se ns 2.4713 12.363 ns cv (%) 15.46 11.82 13.89 12.5 ns = non-significant, i0 =no irrigation; i1= 25 das; i2 = 25 das and 40 das b0 =control; b1= 80% recommended dose as basal + rest 20% as foliar spray at preflowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf number of branches plant-1 effect of irrigation from the study it was found that irrigation had great influence on the number of branches per plant in lentil (figure 5). the highest number of branches per plant (4.79, 4.93 and 5.15 at 50, 65 das and at harvest respectively) was recorded from i2 (25 das and 40 days after sowing) and the lowest (3.26, 3.05 and 3.55 at 50, 65 das and at harvest respectively) was recorded from i0(control). rahman (1994) also reported that two irrigations gave the highest number branches per plant and the lowest was found in case of without irrigation. growth performance of lentil by the effect of irrigation i0 = no irrigation, i1 = 25 das, i fig. 5. response of irrigation on number of branches plant (se = 0.2719, 0.127, 0.1085 at 50, 65 das and at harvest respectively) effect of boron the number of branches per plant of lentil also significantly increase treatments at different days after sowing (figure branches plant-1 (4.37, 4.48, 4.60 at 50, 65 das and at harvest) was obtained from b recommended dose as basal + 60% as foliar spray at b2 (60% rd as basal + rest 40% as fs at pf) at 65 das and at harvest. likewise, the lowest number of branches plant-1 (3.72, 3.89, 3.95 at 50, 65 das (control) followed by b1 (80% rd as basal + rest 20% as fs at pf). b0 = control; b1 = 80% as recommended dose + rest 20% as foliar spray at pre rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf fig. 6. response of boron application on number of branches plant (se= 0.2385, 0.2527, 0.161 at 50, 65 das and at harvest respectively) 0 1 2 3 4 5 6 50 das n um be r o f b ra nc he s p la nt -1 0 1 2 3 4 5 50 das n um be r o f b ra nc he s p la nt -1 days after sowing f irrigation 149 = 25 das, i2 = 25 das & 40 das response of irrigation on number of branches plant-1 of lentil at different days after sowing 50, 65 das and at harvest respectively). umber of branches per plant of lentil also significantly increased by different levels of boron ure 6). results exposed that the highest number of (4.37, 4.48, 4.60 at 50, 65 das and at harvest) was obtained from b3 (40% recommended dose as basal + 60% as foliar spray at pre-flowering) which was statistically same with (60% rd as basal + rest 40% as fs at pf) at 65 das and at harvest. likewise, the lowest number of (3.72, 3.89, 3.95 at 50, 65 das and at harvest separately) was recorded from b0 (80% rd as basal + rest 20% as fs at pf). = 80% as recommended dose + rest 20% as foliar spray at preflowering; b2 = 60% rd as basal + = 40% rd as basal + rest 60% as fs at pf response of boron application on number of branches plant-1 of lentil at days after sowing 50, 65 das and at harvest respectively). 65 das at harvest days after sowing i₀ i₁ i₂ 65 das at harvest days after sowing b₀ b₁ b₂ b₃ 150 paul et al. interaction effect of irrigation and boron interaction effect of different levels of irrigation and boron application on number of branches plant-1 also showed significant variation at different days after of sowing (table 3). result represented that the highest number of branches plant-1 (5.34, 5.45 and 5.74 at 50, 65 das and at harvest) was recorded from i2b3 combination. correspondingly, the lowest number of branches plant-1 (3.12, 3.45 and 3.55 at 50, 65 das and at harvest,) was collected from i0b0 treatment combination which was statistically similar with i0b1 and i0b2 followed by i0b3,i1b0 and i1b1. table 3. interaction effect of irrigation and boron on the number of branches plant-1 of lentil at different days after sowing treatment combinations number of branches plant-1 at 50 das 65 das at harvest i0b0 3.11 c 3.45 d 3.55e i0b1 3.16 c 3.47 cd 3.55 e i0b2 3.33 c 3.54 cd 3.55 e i0b3 3.45 bc 3.55 cd 3.56 e i1b0 3.68 bc 3.69 cd 3.70 de i1b1 3.72 bc 3.74 cd 3.79 de i1b2 3.89 a-c 3.98 b-d 3.87 c-e i1b3 4.32 a-c 4.45 a-d 4.51 b-d i2b0 4.37 a-c 4.54 a-d 4.62 bc i2b1 4.56 a-c 4.69 a-c 4.97 ab i2b2 4.89 ab 5.06 ab 5.29 ab i2b3 5.33 a 5.45 a 5.73 a se 0.4131 0.4378 0.2789 cv (%) 17.94 18.33 11.43 ns = non-significant, i0 =no irrigation; i1= 25 das; i2 = 25 das and 40 das b0 =control; b1= 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf dry matter plant-1 effect of irrigation in case of irrigation, major variability was observed in total dry matter (figure 7). the figure indicated that plant dry matter increased with advancement of growth stage irrespective of irrigation levels. it can be concluded from the figure that two irrigations (i1 and i2) produced the maximum amount of plant dry matter (1.30, 2.58, 3.54 and 4.44 g at 35, 50, 60 das and at harvest) and control (i0) showed the minimum (1.23, 2.30, 3.39 and 3.82 g at 35, 50, 60 das and at harvest) for sampling dates of 25 das and 40 days after sowing. a similar result was founded by latif (2006), wherewith two irrigations he found more dry matter plant-1 on mustard than with one irrigation. growth performance of lentil by the effect of irrigation 149 ns = non-significant, i0 = no irrigation; i1 = 25 das; i2 = 25 das and 40 das fig. 7. response of irrigation application on dry matter (g) plant-1 of lentil atdifferent days after sowing (se= 0.0508, 0.056, 0.4946, 0.4956 at 35, 50, 65 das and at harvest respectively). effect of boron in all the durations observed, substantial variability in plant dry matter was found due to boron (figure 8). the figure showed that plant dry matter weight showed an increasing trend with advances of time for all boron levels. the rate of increase was found slow up to 35 das after that dry weight increased up to harvest irrespective of boron levels. the figure showed that b3 (40% recommended dose as basal + rest 60% as fs at pf) had produced the highest dry matter weight (1.34, 2.57, 3.51and 4.40 g at 35, 50, 65 das and at harvest) and control (b0) showed that the lowest (1.28, 2.41, 3.19 and 3.39 g at 35, 50, 65 das and at harvest) respectively. b0 = control; b1 = 80% as recommended dose + rest 20% as foliar spray at preflowering; b2 = 60% rd as basal +rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf fig. 8. response of boron application on dry matter (g) plant-1 of lentil at different days aftersowing (se = at 1.030, 1.039, 1.038, 1.469 35, 50, 65 das and at harvest respectively). 0 1 2 3 4 5 35 das 50 das 65 das at harvest d ry m at te r ( g) p la nt ⁻¹ days after sowing i₀ i₁ i₂ 0 1 2 3 4 5 35 das 50 das 65 das at harvest d ry m at te r(g ) p la nt ⁻¹ days after sowing b₀ b₁ b₂ b₃ 150 paul et al. interaction effect of irrigation and boron it revealed from (table 4) that the combined effect of two levels of irrigation at (25 and 40 days after sowing) with boron at (40% recommended dose as basal + rest 60% as foliar spray at pre-flowering) gave the significant highest dry matter per plant at all growth stages. the results revealed that the vast plant dry matter (4.77 g) was found from i2b3 at harvest which was statistically identical with i2b2, i2b1, i1b2, i1b3 and i1b2 (at 50, 65 das and at harvest). the lowest dry matter (1.30, 2.26, 2.72 and 3.51 g at 35, 50, 65 das and at harvest) was found from i0b0(control). table 4. interaction effect of different levels of irrigation and boron on dry matter of lentil at different days after sowing [ treatment combinations dry weight (g) plant-1 at 35 das 50 das 65 das at harvest i0b0 1.30 2.26 2.72 ab 3.51 i0b1 1.30 2.25 3.13 b 3.54 i0b2 1.29 2.25 3.16 b 2.97 i0b3 1.28 2.26 3.18 b 3.25 i1b0 1.22 2.27 3.26 ab 3.78 i1b1 1.29 2.25 3.33 ab 4.84 i1b2 1.37 2.31 3.34 ab 3.62 i1b3 1.39 2.32 3.38 ab 3.63 i2b0 1.31 2.32 4.45 ab 3.27 i2b1 1.28 2.36 4.36 ab 4.74 i2b2 1.30 2.38 3.73 ab 4.75 i2b3 1.31 2.41 4.21 ab 4.77 se ns ns 0.6709 ns cv (%) 13.63 17.76 15.45 16.31 ns = non-significant, i0 =no irrigation; i1= 25 das; i2 = 25 das and 40 das b0 =control; b1= 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf interaction effect of irrigation and boron on days to flowering and days to maturity days to flowering of lentil showed substantial variability due to different levels irrigation and boron treatment. the highest days to flowering (56 days) was recorded from i0b2 treatment, while the lowest (52 days) was recorded from i1b1 (table 5). statistically significant differences were found for days to pod maturity of lentil due to different levels of irrigation and boron treatment. the maximum days to pod maturity (94 days) was recorded from i2b3, which was statistically similar to i2b2, i2b1, i1b1, i2b1 and i2b3. the minimum days to pod maturity (88 days) was recorded from i0b0, which was statistically similar to i0b1, i0b2 and i0b3, respectively. growth performance of lentil by the effect of irrigation 149 table 5. interaction effect of irrigation and boron on days to flowering and daysto maturity of lentil at different days after sowing treatment combinations days to flowering days to maturity i0b0 55.78 ab 88.99 d i0b1 55.12 a-c 89.37 d i0b2 56.18 a 89.89 cd i0b3 55.77 ab 89.85 cd i1b0 53.51 a-c 91.22 b-d i1b1 52.52 c 92.43 a-c i1b2 52.91 bc 94.00 a i1b3 53.24 a-c 93.87 a i2b0 54.04 a-c 94.10 a i2b1 53.35 a-c 93.91 a i2b2 53.40 a-c 93.77 ab i2b3 54.13 a-c 94.32 a se 0.538 0.7112 cv (%) 1.72 1.34 ns = non-significant, i0 =no irrigation; i1= 25 das; i2 = 25 das and 40 das b0 =control; b1= 80% recommended dose as basal + rest 20% as foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf conclusion in conclusion,it was observed that the combined effect of irrigation and boron levels had influenced growth factors including plant length (cm), number of leaves plant-1, number of branches plant-1, dry matter (g) content of lentils. in this study, irrigation for two times at 25 and 40 days after sowing and boron at 40% basal along with 60% as foliar spray at pre-floweringhave shown better outcome on lentil production. this recommended combination of irrigation and boron application could be utilized as an effective method for increasing growth and production of lentil. acknowledgement the authors avail the opportunity to express their sincere thanks and heartfelt gratitude to the government of the people’s republic of bangladesh through its ministry of science and technology (most) for providing financial support for conducting field experiment and preparation of the thesis for awarding ms degree in agronomy, sher-e-bangla agricultural university, dhaka-1207. 150 paul et al. references abdo, f. 2001. the response of two mungbean cultivars to zinc, manganese and boron i. morphological, physiological and anatomical aspects. bull. fac. agric. univ. cairo, 52(3): 445-466. bbs. 2018. statistical yearbook of bangladesh. bangladesh bureau of statistics. ministry of planning, govt. of the people’s republic of bangladesh, dhaka. brown, p.h., n. hu. h. bellaloui, and a. dandekar, 1999. transgenically enhanced sorbitol synthesis facilitates phloem boron transport and increases tolerance of tobacco to boron deficiency. plant physiol. 119(1): 17-20. debaeke, p. and a. aboudrare. 2004. adaptation of crop management to waterlimited environments. europ. j. agron.21(4): 433-446. dordas, c., g.e. apostolides and o. goundra. 2007. boron application affects seed yield and seed quality of sugar beets. j. agric. sci.145(4): 377-384. fao. 2013. http://faostat.fao.org/ hosseini, f., a. nezami, m. parsa and g.k. hajmohammadnia. 2011. effects of supplementary irrigation on yield and yield components of lentil (lens culinaris medik.) cultivars in mashhad climate. j. water soil (agric. sci. technol.) 25(3): 625-633. latif, m.m.a. 2006. influence of irrigation and nitrogen on the yield of rapeseed (brassica napus). ms thesis, dept. of agronomy, bangladesh agril. univ., mymensingh, bangladesh. marschner, h. 1995. mineral nutrition of higher plants. 2nd. edn. academic pres. pang, x.p., j. letey and l. wu. 1997. irrigation quantity and uniformity and nitrogen application effects on crop yield and nitrogen leaching. soil sci. soc. america j.61(1): 257-261. pilbeam, d.j. and e.a. kirkby. 1983. the physiological-role of boron in plants. j. plant nutr. 6(7): 563582. piri, i., m.m. nik, a. tavassoli and f. rastegaripour. 2011. effect of irrigation intervals and sulphur fertilizer on growth analyses and yield of brassica juncea. afr. j. microbiol. res. 5(22): 36403646. rahnema, a.a. and a.m. bakhshandeh. 2006. determination of optimum irrigation level and compatible canola varieties in the mediterranean environment. asian j. plant sci. 5(3): 543-546. reddi, g.h.s. and t.y.reddi. 1995. irrigation of principal crops. in:efficient use of irrigation water, 2nd ed. kalyani pub., new delhi. pp.229-259. sezen, s.m., a. yazar and s. eker. 2006. effect of drip irrigation regimes on yield and quality of field grown bell pepper. agric. water mngt. 81(1-2): 115-131. singh, a., m. khan and s. arun. 2014. effect of boron and molybdenum application on seed yield of mungbean. asian j. biol. sci. 9(2): 169-172. subasinghe, s., g. dayatilake and r. senaratne. 2003. effect of b, co and mo on nodulation, growth and yield of cowpea (vigna unguiculata). trop. agric. res. ext. 6: 108-112. vimalan, b., p. gayathri, s. thiyageshwari and j. prabhaharan. 2017. effects of boron on the seed yield and protein content of green gram (vigna mungo) var. co 8. life sci. int. res. j.4(1): 90-92. plant height effect of irrigation effect of boron interaction effect of irrigation and boron effect of irrigation effect of born interaction effect of irrigation and boron effect of irrigation effect of boron interaction effect of irrigation and boron effect of irrigation effect of boron interaction effect of irrigation and boron conclusion acknowledgement references bangladesh agron. j. 2019, 22 (1): 57-69 effect of water, nutrient and weed management on the yield and quality of aromatic boro rice (cv. brri dhan50) s.k. paul*, m.c. ray, m.a.r. sarkar and s.k. sarkar department of agronomy, bangladesh agricultural university, mymensingh 2202, bangladesh *corresponding e-mail: skpaul@bau.edu.bd (received: 25 april 2019, accepted: 30 july 2019) keywords: yield, grain protein, aromatic bororice abstract an experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh during january to june 2016 to observe the effect of water, nutrient and weed management practices on the yield and quality of aromatic boro rice (cv. brri dhan50). the experiment consisted of three water managements viz. conventional flood irrigation, awd (alternate wetting and drying) and sri (system of rice intensification); two nutrient managements viz. recommended dose of inorganic fertilizers (urea, tsp, mop, gypsum, znso4 @ 250, 120, 120, 100, 10 kg ha -1, respectively) and 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1; and three weed managements viz. weedy check (control), two hand weeding at 20 and 40 dat, and pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) application. the highest number of effective tillers hill-1, grains panicle-1,grain yield and protein (%) in grain were obtained in sri water management which was followed by awd and conventional flood irrigation. between the two nutrient management practices, application of 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 produced higher number of effective tillers hill-1,grains panicle-1,1000-grain weight, grain yield and protein (%) in grain than in organic fertilizer. among the weed management practices, application of pre-emergence herbicide (rifit 33ec) followed by post-emergence herbicide (fast klin 10wp) produced the highest number of effective tillers hill-1,grains panicle1,1000-grain weight, grain yield and protein (%) in grain followed by two weedings at 20 and 40 dat while the lowest grain yield was obtained in weedy check. the highest number of effective tillers hill-1,grains panicle1, grain yield and protein (%) in grain was found in sri water management combined with 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 and application of preemergence herbicide followed by post-emergence herbicide. so, it may be concluded that, to get the highest grain yield in aromatic boro rice, sri method along with application of 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 and applying preemergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) could be recommended. introduction rice (oryza sativa) is the most extensively cultivated cereal crop in bangladesh. aromatic rice contributes a small portion (10%) but an important subgroup of rice production. in recent years, aromatic rice has been introduced to the global market because of its taste, deliciousness and high price (adhikari et al., 2018). the yield of fine rice is lower than that of coarse and about:blank 58 paul et al. medium rice varieties. to overcome this situation increment of aromatic rice production unit-1 area is the only alternative to bring self-sufficiency in aromatic rice through intensive care, management and adoption of new technologies. irri has developed awd (alternate wetting and drying) technology. this system can save 30% irrigation water, save energy and fuel consumption. awd requires irrigation when the water level goes down to 15 cm below the soil surface. sri (system of rice intensification) is another water saving technology (stool et al., 2002) where minimum water input with intermittent or saturated soil requires 2050% less water (lek and yongyod, 1989) than continuous flooding. in recent years there has been serious concern about long-term adverse effect of continuous and indiscriminate use of inorganic fertilizers on deterioration of soil structure, soil health and environmental pollution (ghosh and bhat, 1998). combined application of manure with inorganic fertilizers increased grain yield and protein content of aromatic rice (sarkar et al., 2014, roy et al., 2015; pal et al., 2016; biswas et al., 2016 and marzia et al., 2016). high competitive ability of weeds exerts a serious negative effect on crop production causing significant losses in crop yield. yield losses due to weed infestation are greater than the combined losses of insect pests and diseases. in bangladesh, weed infestation reduces the grain yield 70-80% in aus rice, 30-40% for transplanted aman rice and 22-36% for modern boro rice cultivars (mamun, 1990). in case of aromatic rice grain yield was reduced by 28.16% in binadhan-9 in aman season (zannat et al., 2014) whereas by 59.82% in brri dhan50 at boro season (sinha et al., 2018) due to weed infestation. herbicides are effective in controlling weeds alone or in combination with hand weeding (ahmed et al., 2005). herbicides in combination with hand weeding would help to obtain higher crop yield with less efforts and cost (prasad and rafy, 1995; sathyamoorthy et al., 2004). so, the present study was undertaken to find out the effect of water, nutrient and weed management on the growth, yield and quality of aromatic bororice (cv. brri dhan50). materials and methods the experiment was carried out at the agronomy field laboratory of bangladesh agricultural university, mymensingh during january to june 2016 to study the effect of water, nutrient and weed management practices on the performance of aromatic boro rice. the experimental field was located at 24o°75'n latitude and 90o°50'e longitude at an elevation of 18m above the mean sea level. the experimental area belongs to non-calcareous dark grey floodplain soil under the sonatola soil series of old brahmaputra floodplain in agro ecological zone (aez9) (undp and fao, 1988). the experimental field was medium high, fairly leveled with well drained soils. the soils of this series are pre-dominantly silty loam, dark grey in color having ph 6.5 and low in organic matter. the experiment comprised three water management viz. conventional flood irrigation (i1), awd (alternate wetting and drying) (i2) and sri (system of rice intensification) (i3); two levels of nutrient management viz. recommended dose of inorganic fertilizer (urea, tsp, mop, gypsum, znso4 @ 250, 120, 120, 100, 10 kg ha-1 respectively) (f1) and 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 (f2), and there levels of weed management viz. weedy check (control) (w0),two hand weedings at 20 and 40 (days after transplanting) dat (w1) and application of pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) (w2). the experiment was laid out in a randomized complete block design with three replications. eachunit plot size was 4.0 m × 2.5m. the rice var. brri effect of water, nutrient and weed management 59 dhan50 of aromatic boro rice was used as the test crop. sprouted seeds were sown in the nursery bed on 13 december 2015 for awd and continuous flooding practices. in sri method seeds were sown in 11 january 2016. the experimental plots were fertilized with as per experimental treatments. the entire amounts of triple super phosphate, muriate of potash, gypsum and zinc sulphate and poultry manure were applied at final land preparation. urea was applied in three equal installments at 15, 30 and 45 dat. the seedlings were uprooted on 26 january 2016 without causing much mechanical injury to the roots and they were immediately transplanted in the well puddled main fieldat the rate of two seedlings hill-1, maintaining row and hill distance of 25 cm and 15 cm in awd and conventional flooding systems. in case of sri, single seedling hill-1 was used12-day old seedlings whereas conventional and awd systems 30-day old seedlings were used. awd is monitored the depth of irrigated water on the field using a ‘field water tube’ or magic pipe. it involves installation of a perforated pipe in the rice field to allow observation of water level. in this experiment, magic pipe was installed at 10 dat. after irrigation, the depth of irrigation water will gradually decrease. when the irrigation water has dropped to 15 cm below the surface of the soil, irrigation was applied with 5 cm depth water. from one week before to one week after flowering, irrigation water was kept at 5 cm depth. after flowering, the water level was dropped again to 15 cm below the surface before irrigation. water management was the most complicated variable in sri method where rice crops are kept unflooded during vegetative growth with partial amount of water was applied to keep the soil moist.it was even allowed to dry out for 2 to 4 days during tillering to keep the soil well aerated and to allow better root growth. from panicle initiation (pi) to hard dough stage, a thin layer of water (2-3 cm) was kept on the plots. again water was drained out from the plots during ripening stage. data on weed population were recorded from each plot at 65 dat by using 1 m2 quadrate as per method described by cruz et al. (1986). the weeds inside each quadrate were uprooted and cleaned, separated species-wise and dried first in the sun and then in an electrical oven for 72 hours at a temperature of 80 oc followed by weed dry weight of each plot was recorded by an electrical balance. the crop was harvested on 25 may, 30 may and 06 june 2016, respectively for conventional, awd and sri. the grains were cleaned and finally the weight was adjusted to a moisture content of 14%. the straw was sun dried and the yields of grain and straw plot-1 were recorded and converted to t ha-1. harvest index indicates the ratio of economic yield (grain yield) to biological yield (grain yield + straw yield) and was calculated by the following formula: harvest index (%) = ×x 100. estimation of protein in grains was done by following micro-kjeldahl method. oven dried rice kernels were then put in polythene bags and kept in desiccators for subsequent chemical analysis for estimation of protein. protein content (%) was estimated by micro-kjeldahl method (aoac, 1984) at the agri-varsity humboldt soil testing laboratory of soil science department, bangladesh agricultural university, mymensingh. the recorded data were compiled and tabulated for statistical analysis. analysis of variance was done with the help of computer package, mstat. the mean differences among the treatments were adjudged by duncan’s multiple range test (gomez and gomez, 1984). 60 paul et al. results and discussion weed dry weight there was significant effect on total weed dry weight (g m-2) due to water management (table 1). the highest total weed dry weight (38.71 g m-2) was found in i1 (conventional flood irrigation) followed by awd (alternate wetting and drying), while the lowest total weed dry weight (33.35 g m-2) was found in i3 (sri) water management (table 1).there was significant effect on total weed dry weight due to nutrient management (table 1). maximum weed dry weight (37.75 g m-2) was found in f1 (recommended dose of inorganic fertilizer) and minimum one (33.56 g m-2) was found in f2 (25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1) nutrient management (table 1). there was significant effect on total weed dry weight due to weed management (table 1). at 65 dat, the maximum total weed dry weight (75.03 g m-2) was found in w0 (no weeding) followed by two hand weedings at 20 and 40 dat while the lowest total weed dry weight (8.91 g m-2) in w2 (pre-emergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp) weed management (table 1).non-significant variation was found on total weed dry weight due to interaction effect of water and nutrient management at 65 dat (table 2). however, numerically, the highest weed dry weight (41.43 g m-2) was found in i1×f1 (conventional flood irrigation × recommended dose of inorganic fertilizer) and the lowest (31.35 g m-2) one was found in i3×f2 (sri × 25% less than recommended dose of inorganic fertilizer + poultry manure) treatment (table 2). significant variation was found on total weed dry weight due to interaction effect of water and weed management at 65 dat (table 3). the highest weed dry weight (80.48 g m-2) was found in i1×w0 (conventional flood irrigation × no weeding) followed by i2 × w0 (awd × no weeding) and i3 × w0 (sri × no weeding) and the lowest (7.66 g m -2) one was found on i3×w2 (sri × pre-emergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp) treatment (table 3).significant variation was found on total weed dry weight due to interaction effect of nutrient and weed management practices at 65 dat (table 4). the highest total weed dry weight (77.74 g m-2) was found in f1×w0 (recommended dose of inorganic fertilizer × no weeding) and the lowest (8.692 g m-2) one was found in f1×w2 (recommended dose of inorganic fertilizer× pre-emergence herbicide rifit 33ec followed by postemergence herbicide fast klin 10wp) treatment (table 4). non-significant variation was found on total weed dry weight due to interaction effect of water, nutrient and weed management practices at 65 dat (table 5). yield and yield components crop characters, yield contributing characters, yield and grain protein content were significantly influenced by water management except panicle length and 1000-grain weight (table 1). the tallest plant (82.56 cm), number of total tillers hill-1 (12.25), effective tillers hill-1 (11.07) and grains panicle-1 (119.99) were found in i3 (sri method) followed by i2 (awd) and all parameters showed the lowest values in i1 (conventional flood irrigation) (table 1). while the highest number of non-effective tillers hill-1(1.44) was recorded in awd (alternate wetting and drying) and sterile spikelets panicle-1 (16.12) were recorded in i1 (conventional flood irrigation) and the lowest values were found in i3 (sri). the highest grain yield (5.41 t ha-1) was obtained in i3 (sri) water management followed by i2 (awd) and the lowest grain yield (4.80 t ha-1) in i1 (conventional flood irrigation). the increased yield might be due to the highest number of grains panicle-1 and number of effective tillers hill-1. straw yield also showed similar trend as that of grain yield. the highest grain protein content (8.54%) was found in i3 effect of water, nutrient and weed management 59 (sri) followed by i2 (awd) and the lowest grain protein content (7.96%) in i1 (conventional flood irrigation). table 1. effect of water management on crop characters, yield components and yield of aromatic boro rice (cv. brri dhan50) treatments dry matter of weed (g m-2) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) panicle length (cm) grains panicle-1 (no.) no. of sterile spikelets panicle-1 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) grain protein content (%) water management i1 38.71a 76.96b 10.49b 9.08b 1.41a 21.36 116.11c 16.12a 18.30 4.80c 5.20c 48.00 7.957b i2 34.90b 82.49a 10.92b 9.48b 1.44a 21.64 117.03b 14.11b 18.64 4.99b 5.46b 47.75 8.093b i3 33.35c 82.56a 12.25a 11.07a 1.18b 21.89 119.99a 13.75c 19.32 5.41a 6.05a 47.20 8.536a cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 nutrient management f1 37.75a 80.69 10.81b 9.40b 1.41a 21.52 114.40b 15.10a 18.41b 4.72b 5.37b 46.78 8.00b f2 33.56b 80.66 11.63a 10.36a 1.28b 21.74 117.68a 14.22b 19.15a 5.03a 5.77a 46.57 8.26a cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 weed management w0 75.03a 78.81b 9.13c 8.17c 0.96c 21.22 b 116.53 16.50a 18.12b 2.91c 3.80c 43.36c 7.92b w1 23.03b 81.46a 11.62b 9.97b 1.65a 21.57ab 118.05 14.03b 18.50b 5.10b 6.19b 45.17b 8.12b w2 8.91c 81.75a 12.91a 11.50a 1.41b 22.10a 120.55 13.46c 19.64a 5.75a 6.73a 46.07a 8.54a cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 in a column, figures with same letter or without letter do not differ significantly (as per dmrt). i1 = conventional flood irrigation, i2 = awd (alternate wetting and drying), i3 = sri (system of rice intensification), f1 = recommended dose of inorganic fertilizer, f2 = 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha -1, w0 = weed check (control), w1 = two hand weeding at 20 and 40 dat, w2 = pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) all yield contributing characters, yield and grain protein content were significantly influenced by nutrient management except plant height and panicle length (table 1). the highest number of total tillers hill-1 (11.63), effective tillers hill-1 (10.36), grains panicle-1 (117.68) and 1000-grain weight (19.15 g) were found in all the parameters showed lower values in f1.the highest number of non-effective tillers hill-1 (1.41) and sterile spikelets panicle-1 (15.10) were produced in f1 nutrient management, while the lowest number of sterile spikelets panicle-1 (14.22) in f2 (25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1). higher grain yield (5.03 t ha-1) and straw yield (5.77 t ha-1) were obtained in f2 (25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1) nutrient management than that of f1.the increased yield might be due to higher number of grains panicle-1, higher 1000-grain weight and higher number of effective tillers hill-1. application of inorganic fertilizer along with manure greatly influence the grain yield of rice were reported (islam et al., 2015; roy et al., 2015; pal et al., 2016; biswas et al., 2016 and sarkar et al., 2016). table 1 indicates that higher grain protein content (8.26%) was found in f2 compared to f1. integration of poultry manure with chemical fertilizer increased grain protein content was also reported (sarkar et al., 2014; biswas et al., 2016 and pal et al., 2016) crop characters, yield contributing characters, yield and grain protein content were significantly influenced by water management except grains panicle-1 (table 1). the tallest plant (81.75 cm) was found in w2 (pre-emergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp) which was at par with w1(two hand weeding at 20 and 40 dat) while the shortest plant (78.81 cm) was found in w0 (no weeding). the highest number of total tillers hill -1 (12.91), effective tillers hill-1 (11.50), longest panicle (22.10 cm) and the highest weight of 1000-grain (19.64 g) were obtained in w2 whileall the parameters showed intermediate values in w1and the corresponding lowest values in w0. the highest number of non-effective tillers hill-1 (1.65) was produced in w1 while the lowest number of non-effective tillers hill-1 (0.96) in w0. the highest number of sterile spikelets panicle-1 (16.50) was produced in w0 weed management, while the lowest number of sterile spikelets panicle-1 (13.46) in w2. number of grains panicle-1 was not significantly influenced by different weed management. table 1 indicates that numerically the highest number of grains panicle-1 (120.55) was produced in w2 while the lowest number of grains panicle -1 (116.53) by w0. the highest grain yield (5.75 t ha-1), straw yield (6.73 t ha-1) and harvest index (46.07%) were produced in w2 followed by w1 while the corresponding lowest values were obtained in w0. weed infestation reduced 49.39% grain yield over w2. similar trend was reported by sinha et al. (2018) that weed reduced grain yield by 59.83% in aromatic boro rice cv. brri dhan50. the highest grain protein content (8.54%) was found in w2 and the lowest grain protein content (7.92%) in w0which was at par with w1. table 2 indicates that the highest number of total tillers hill-1(12.78), effective tillers hill-1 (11.67), and grain yield (5.19 t ha-1 t ha-1) were obtained in i3 × f2 (sri × 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1t). grain yield produced in i3 × f1 (sri × recommended dose of inorganic fertilizer) was at parini3 × f2 (sri-25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 t) while the corresponding lowest values in i1 f1 (conventional flood irrigation × recommended dose of inorganic fertilizer). table 2. interaction effect of water and nutrient management on crop characters, yield components and yield aromatic boro rice (cv. brri dhan50) interaction (water × nutrient management) dry matter of weed (g m2) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) panicle length (cm) grains panicle1 (no.) no. of sterile spikelets panicle-1 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) grain protein content (%) i1 × f1 41.43 82.59 10.15c 8.64d 1.52 21.22 113.40 16.89 18.07 4.76c 5.01 48.72 7.58 i1 × f2 35.98 82.54 10.82bc 9.52bc 1.29 21.50 114.82 15.35 18.54 4.92b 5.44 47.49 7.93 i2 × f1 36.43 82.14 10.51bc 9.09c 1.42 21.66 115.10 14.31 18.27 4.80bc 5.28 47.61 7.94 i2 × f2 33.36 82.84 11.32b 9.87bc 1.45 21.63 116.96 13.92 19.00 4.95b 5.65 46.69 8.24 i3 × f1 35.35 77.35 11.74ab 10.47b 1.27 21.67 115.71 14.12 18.87 4.98ab 5.86 45.94 8.48 i3 × f2 31.35 76.58 12.78a 11.67a 1.09 22.10 118.26 13.38 19.77 5.19a 6.24 45.40 8.59 cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 in a column, figures with same letter or without letter do not differ significantly (as per dmrt). i1 = conventional flood irrigation, i2 = awd (alternate wetting and drying), i3 = sri (system of rice intensification) f1 = recommended dose of inorganic fertilizer, f2 = 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha table 3 indicates that the highest number of grains panicle-1(119.0) was produced in i3 × w2 (sri × pre-emergence herbicide rifit 33ec followed by post-emergence herbicide fast klin 10wp) which was at par to i2 w2 (awd pre-emergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp). the highest grain yield (6.14 t ha-1) was produced in i3 w2 followed by i3 w2 (sri two hand weeding at 20 and 40 dat) (6.14 t ha -1) and the lowest grain yield (2.70 t ha-1) in i1 ×w0 (conventional flood irrigation × no weeding). the highest number of effective tillers hill-1(11.96) was obtained in f2 × w2 (25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 × pre-emergence herbicide rifit 33ec followed by post-emergence herbicide fast klin 10wp) followed by f1×w2 (recommended dose of inorganic fertilizer preemergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp) and lowest one (7.79) in f1×w0 (recommended dose of inorganic fertilizer no weeding) table 3. interaction effect of water and weed management on crop characters, yield components and yield of aromatic boro rice (cv. brri dhan50) in a column, figures with same letter or without letter do not differ significantly (as per dmrt). i1 = conventional flood irrigation, i2 = awd (alternate wetting and drying), i3 = sri (system of rice intensification), w0 = weed check (control), w1 = two hand weeding at 20 and 40 dat, w2 = pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) interaction (water × weed management) dry matter of weed (g m-2) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) panicle length (cm) grains panicle-1 (no.) no. of sterile spikelets panicle-1 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) grain protein content (%) i1 × w0 80.48a 81.47 8.39 7.40 0.99d 20.87 116.40de 20.10a 17.71 2.70e 3.45 43.90 7.35 i1 × w1 25.80c 83.65 10.88 9.14 1.74ab 21.32 117.00cd 14.53bc 18.12 5.07c 5.81 46.59 7.82 i1 × w2 9.832e 82.57 12.20 10.70 1.50b 21.90 117.93b 13.73cd 19.08 5.43bc 6.35 46.09 8.11 i2 × w0 73.46b 81.15 8.71 7.79 0.91e 21.25 116.58d 14.85b 17.92 2.83de 3.73 43.14 7.83 i2 × w1 22.00d 83.08 11.47 9.54 1.93a 21.60 116.86d 13.96bd 18.40 5.41bc 6.19 46.63 7.99 i2 × w2 9.236e 83.24 12.57 11.11 1.47b 22.08 118.63ab 13.53cd 19.60 5.69b 6.48 46.75 8.46 i3 × w0 71.10b 73.81 10.30 9.31 0.99d 21.55 117.61bc 14.56bc 18.74 3.21d 4.20 43.34 8.28 i3 × w1 21.28d 78.51 12.50 11.23 1.28c 21.80 117.28c 13.59cd 19.00 5.69b 6.58 46.37 8.46 i3 × w2 7.662e 78.57 13.95 12.68 1.27c 22.31 119.0a 13.11d 20.24 6.14a 7.36 45.48 8.87 cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 table 4. interaction effect of nutrient and weed management on crop characters, yield components and yield of aromatic boro rice (cv. brri dhan50) nutrient × weed management dry matter of weed (g m-2) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) panicle length (cm) grains panicle1 (no.) no. of sterile spikelets panicle-1 1000 grain weight (g) grain yield (t ha1) straw yield (t ha1) harvest index (%) grain protein content (%) f1 × w0 77.74a 78.87 8.74 7.79ef 0.95c 21.19 107.53 17.12 17.77 2.78 3.58 43.71 7.71 f1 × w1 26.34c 81.85 11.18 9.37d 1.81a 21.44 109.36 14.39 18.16 5.22 5.98 46.60 7.93 f1 × w2 9.128e 81.35 12.49 11.03b 1.46b 21.93 111.31 13.80 19.29 5.60 6.55 46.09 8.36 f2 × w0 72.28b 78.74 9.52 8.54e 0.98c 21.26 111.52 15.87 18.48 3.05 4.02 43.14 7.93 f2 × w1 19.71d 81.65 12.06 10.57c 1.49b 21.71 112.73 13.67 18.84 5.56 6.40 46.48 8.24 f2 × w2 8.692e 81.57 13.32 11.96a 1.37b 22.26 113.78 13.11 19.99 5.90 6.90 46.09 8.59 cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 in a column, figures with same letter or without letter do not differ significantly (as per dmrt). f1 = recommended dose of inorganic fertilizer, f2 = 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha -1 w0 = weed check (control), w1 = two hand weeding at 20 and 40 dat, w2 = pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) table 5 indicates that the highest number of total tillers hill-1 (14.58), effective tillers hill-1 (13.40) and grains panicle-1 (118.65) were obtained in i3×f2×w2 (sri 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha -1 preemergence herbicide rifit 33ec followed by post emergence herbicide fast klin 10wp) treatment while the corresponding lowest values in i1f1×w0 (conventional flood irrigation × recommended dose of inorganic fertilizer ×no weeding) treatment. table 5. interaction effect of water, nutrient and weed management on crop characters, yield components and yield of aromatic boro rice (cv. brri dhan50) in a column, figures with same letter or without letter do not differ significantly (as per dmrt). i1 = conventional flood irrigation, i2 = awd (alternate wetting and drying), i3 = sri (system of rice intensification) f1 = recommended dose of inorganic fertilizer, f2 = 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha -1 w0 = weed check (control), w1 = two hand weeding at 20 and 40 dat, w2 = pre-emergence herbicide (rifit 33ec) followed by post emergence herbicide (fast klin 10wp) interaction (water × nutrient × weed management) dry matter of weed (g m-2) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) panicle length (cm) grains panicle-1 (no.) no. of sterile spikelets panicle-1 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha1) harvest index (%) grain protein content (%) i1 × f1 × w0 83.30 81.61 8.11f 7.10i 1.01 20.56 114.17fg 21.43 17.49 2.55h 3.25 43.96 7.23 i1 × f1 × w1 31.04 83.21 10.4d 8.49fg 1.91 21.21 117.17bcde 15.19 17.98 4.78e 5.43 46.81 7.58 i1 × f1 × w2 9.960 82.94 11.98c 10.33cde 1.65 21.89 117.93ab 14.05 18.74 5.25de 6.23 45.73 7.93 i1 × f2 × w0 77.67 81.33 8.67ef 7.70g 0.97 21.18 117.70b 18.76 17.93 2.89g 3.66 44.12 7.47 i1 × f2 × w1 20.56 84.09 11.37cd 9.80de 1.57 21.42 117.83abc 13.87 18.25 5.36cde 6.19 46.40 8.05 i1 × f2 × w2 9.703 82.20 12.42b 11.07bcde 1.35 21.90 117.93ab 13.41 19.42 5.62bc 6.47 46.48 8.28 i2 × f1 × w0 75.52 82.13 8.34efg 7.42gh 0.93 21.59 115.10f 15.02 17.50 2.72gh 3.43 44.22 7.60 i2 × f1 × w1 24.03 82.28 11.01cde 9.03defg 1.98 21.48 115.63def 14.18 18.00 5.29d 6.07 46.56 7.82 i2 × f1 × w2 9.733 82.00 12.18bc 10.82c 1.37 21.92 116.50cde 13.71 19.31 5.49cd 6.35 46.36 8.40 i2 × f2 × w0 71.39 80.16 9.07e 8.17fgh 0.90 20.91 116.00de 14.67 18.34 3.00fgh 4.04 42.61 8.05 i2 × f2 × w1 19.96 83.88 11.93c 10.05d 1.88 21.73 117.00c 13.74 18.79 5.52c 6.30 46.70 8.17 i2 × f 2× w2 8.740 84.48 12.96abc 11.40bcd 1.56 22.24 117.77abd 13.35 19.88 5.88b 6.60 47.12 8.52 i3 × f1 × w0 74.40 72.88 9.77de 8.85f 0.92 21.42 116.33d 14.92 18.31 3.15fg 4.06 43.68 8.28 i3 × f1 × w1 23.95 80.05 12.13bc 10.60cd 1.53 21.63 117.30bcd 13.79 18.50 5.59bc 6.43 46.50 8.40 i3 × f1 × w2 7.690 79.10 13.32ab 11.95b 1.36 21.98 117.50bc 13.64 19.81 6.07ab 7.08 46.15 8.75 i3 × f2 × w0 67.79 74.74 10.83cdef 9.77def 1.07 21.68 116.87cd 14.19 19.16 3.27f 4.35 42.91 8.28 i3 × f2 × w1 18.62 76.97 12.87abcd 11.85bc 1.02 21.98 117.87ab 13.39 19.49 5.80b 6.72 46.32 8.52 i3 × f2 × w2 7.634 78.04 14.58a 13.40a 1.18 22.64 118.65a 12.57 20.67 6.20a 7.64 44.79 8.98 cv (%) 6.44 3.62 7.62 5.17 11.84 4.37 8.19 14.46 4.94 3.86 4.00 3.48 4.18 the highest grain yield (6.20 t ha-1) was obtained in i3×f2×w2 followed by i3×f2×w1 while the lowest grain yield (2.55 t ha -1) was found in i1×f1×w0. grain protein content was not statistically significant (table 5). a functional relationship was observed between dry matter weight of weeds (at 65 dat) and grain yield of aromatic boro rice (cv. brri dhan50). a negative linear relationship between weed dry weight (at 65 dat) and grain yield of aromatic boro rice was observed, indicating that higher the weed dry matter value lower the grain yield (figure 1). the functional relationship adequately described by regression equation y = -0.0445x + 6.2706 (r² = 0.9714). the functional relationship indicates that 97% of the variation in grain yield could be explained from the variation in weed dry matter production at 65 dat. this finding is in agreement with that of sinha et al. (2018) who reported that 89% of boro rice (cv. brri dhan50) yield could be explained by the functional relationship of weed dry matter production at 65 dat while islam et al. (2015) reported that 80% of the variation in grain yield could be explained from the variation in weed dry matter production at 60 dat in brri dhan49. conclusion the highest number of effective tillers hill-1,grains panicle-1, grain yield and protein (%) in grain was found in sri water management along with 25% less than recommended dose of inorganic fertilizer + poultry manure @ 2.5 t ha-1 and application of pre-emergence herbicide followed by post emergence herbicide. therefore, it could be concluded that sri method along with application of 25% less than recommended dose of inorganic fertilizer + poultry @ 2.5 tha-1 and pre-emergence herbicide (rifit 33ec) followed by post-emergence herbicide y = -0.0445x + 6.2706 r² = 0.9714 0 1 2 3 4 5 6 7 0 20 40 60 80 100 g ra in y ie ld ( t/ h a) weed dry weight (g/m2) effect of water, nutrient and weed management 59 (fast klin 10wp) may be recommended for higher grain yield and quality in terms of grain protein content in aromatic boro rice cv. brri dhan50. acknowledgement the financial assistance of ministry of science and technology, govt. of the people’s republic of bangladesh, to conduct the research project is thankfully acknowledged. references adhikari, a., m.a.r. sarkar, s.k. paul and k.k. saha. 2018. impact of nutrient management on the yield performance of some aromatic fine rice (oryza sativa l.) varieties in boro season. arch. agr. environ. sci. 3(3): 245251. ahmed, g.j.u., m.k.a. bhuiyan, c.r. riches, m. mortimer and d. jhonson. 2005. farmer’s participatory studies of integrated weed management system for intensified lowland. proceeding of the 8th biennial agronomy convention, bangladesh agron. j. 31-32. aoac. 1984. official methods of analysis. association of official agricultural chemists. washington, d. c. pp. 121-135. biswas, t., s.k. paul, m.a.r. sarkar and s.k. sarkar. 2016. integrated use of poultry manure with prilled urea and urea super granules for improving yield and protein content of aromatic rice (cv. brri dhan50). prog. agric. 27(2): 86-93. cruz, e.d., k. moody and m.b.d. ramos. 1986. reducingvriability in sampling weeds in upland rice (oryza sativa). philipp. j. weed sci. 13: 56-59. ghosh, b.c. and r. bhat. 1998. environment hazards of nitrogen loading in wetland rice fields. environ. pollut. 102: 123-126. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research. intl. rice res. inst., philippines, john wiley and sons. new york, chichester, brisbane, toronto, singapore.680p. islam, s.m.m., s. k. paul and m.a.r. sarkar. 2015. effect of weeding regime and integrated nutrient management on yield contributing characters and yield of brri dhan49. j. crop weed. 11 (special issue): 193-197. lek, p. and s. yongyod. 1989. water management for wet and dry season rice growing in irrigated area. irrigation station 2-10. paper for 1999 pathunthani. rice research center annual seminar. mamun, a.a. 1990. weeds and their control: a review of weed research in bangladesh. agricultural and rural development in bangladesh.japan intl. cooperation agency, dhaka, bangladesh. jsard. 19: 45-72. marzia, r., m.a.r. sarkar and s.k. paul. 2016. effect of row management and integrated nutrient management on the yield of aromatic fine rice (cv. brri dhan34).int. j. plant soil sci. 13(5): 1-8. pal, s., s.k paul, m.a.r. sarkar and d.r. gupta. 2016. response on yield and protein content of fine aromatic rice varieties to integrated use of cowdung and inorganic fertilizers. j. crop weed. 12(1): 01-06. 60 paul et al. prasad, k. and a. raffy. 1995. effect of integrated weed management on weed growth nutrient uptake, economics and energetics in rainfed upland rice (oryza sativa). indian j. agril. sci. 65(4): 260-264. roy, b., m.a.r. sarkar and s.k. paul. 2015. effect of integrated nutrient management in boro rice cultivation. saarc j. agri. 13(2): 131-140. sarkar, m.a.r., s.k. paul and u. paul. 2016. effect of plant nutrient and weed management in direct wet seeded boro rice. prog. agric. 27(4): 466-472. sarkar, s.k., m.a.r. sarkar, n. islam and s.k. paul. 2014. yield and quality of aromatic fine rice as affected by variety and nutrient management. j. bangladesh agril. univ. 12(2): 279-284. sathyamoorthy, n.k., s. mahendran, r. babu and t. ragavan. 2004. effect of intgrated weed management practices on total weed dry weight, nutrient removal of weeds in rice-rice wet seedbed system. j. agron. 3(4): 263267. sinha, t., s.k. paul. and m.a.r. sarkar. 2018. effect of age of seedlings at staggered transplanting and weed management on the growth and yield of aromatic boro rice (cv. brri dhan50). j. bangladesh agril. univ. 16(1): 5-11. stool, w.a., n. uphoff and a. kassam. 2002. a review of agricultural research issues raised by the system of rice intensification (sri) from madagascar: opportunities for improving farming systems for resource-poor farmers. agril. sys. 71(3): 249-274. undp and fao. 1988. land resources appraisal of bangladesh for agricultural development. report 2. agroecological regions of bangladesh. bangladesh agril. res. coun., dhaka-1207. pp.212-221. zannat, s.t., s.k. paul and m.a. salam. 2014. effect of weeding regime and nitrogen management on the performance of transplant aromatic aman rice (cv. binadhan-9). bangladesh j. seed sci. tech. 18(1 & 2): 29-34. bangladesh agron. j. 2021, 24(2): 83-90 influence of nitrogen dose and application method on growth and yield of baby corn p.k. biswas, n.j. sarna and s. shome department of agronomy, sher-e-bangla agricultural university, dhaka-1207 corresponding e-mail: parimalbiswas@hotmail.com (received: 18 september 2021, received: 25 october 2021) keywords: nitrogen management, cob yield, baby corn abstract the experiment was conducted at sher-e-bangla agricultural university during rabi season of 2019-20 to find out the influence of nitrogen management on cob yield of baby corn. the experiment was laid out in a split-plot design having 3 replications where four nitrogen dose viz., i) 0 kg n ha-1 (n1), ii) 100 kg n ha-1 (n2), iii) 150 kg n ha-1 (n3) and ii) 200 kg n ha-1 (n4) in the main plot and three nitrogenous fertilizer application method viz., i) basal (m1), ii) side dressing at 30 das (m2) and iii) 50% basal + 50% side dressing at 30 das (m3) in the sub-plot. almost all the studied parameters were found statistically significant. the higher plant height, dry matter plant-1, number of cobs plant-1, fresh weight cob-1, husk weight cob-1 and cob yield were observed in application of 200 kg nha-1. basal application of nitrogen fertilizer gave the highest cob weight and husk weight. basal application of 200 kg n ha-1 showed the highest plant height (177.80 cm), cobs plant-1 (2.91), cob length (9.94 cm), fresh cob weight (61.05 g), de-husked cob weight (11.74 g) and husk fresh weight (49.30 g) but the highest number of cobs ha-1 (218497) from n2m3 (100 kg nha-1 applied 50% as basal dose and 50% at 30 das) and highest cob yield (7732.41 kg ha-1) from n4m2 (application of 200 kg nha-1 at 30 das). introduction baby corn refers to the whole, entirely edible cobs of immature corn harvested just before fertilization at 2-3 cm long silk emergence stage. it is emerging worldwide as one of the high value crops due to its high nutritive value, delicious taste and very large demand by the foreign tourists. it is a low calorie vegetable having higher fibre content without cholesterol. no nutrients are utilized for seed set and hence, they are retained in plant part (stover) which make it nutritious cattle feed (bakshi et al., 2016). besides nutritive advantage, it is also freefrom residual effect of pesticides as it is harvested within aweek of tassel emergence and the young cob is wrapped uptightly with husk and well protected from insects and pests. baby corn has primeplace as a safe and quality vegetable. to sustain the heavycattle population, baby corn can provide a valuablesupplementary source of green fodder (bakshi and wadhwa, 2012). baby corn is grown almost throughout the world is an off shoot of maize which is grown for its young, fresh, finger like green ears, harvested at the time of silk emergence and before pollination and fertilization (ramchandrappa et al., 2004). ears are ideal for baby corn if they are bite size, 5-10 cm long and 0.85 – 1.70 cm diameter at the base (bar-zur and saadi, 1990). it contains 10.04g protein, 8.2g carbohydrate, 0.20g fat, o.86g phosphorus, 28 mg calcium and 0.10 mg iron per 100 g of edible portion (thakur et al., 2000). its byproducts such as tassel, young husk silk and green stalk provide feed for cattle and aquaculture (bindhani et al., 2007). moreover stover, dry leaves and cob covering can be used as good fuel (ahmed, 1994 the soil and climate of our country is suitable for baby corn production. at present baby corn is growing in some areas of chittagong hill tracts. the baby corn yield of bangladesh is 0.99 – 1.1 ton per hectare but its potentiality is 5 ton per hectare (bari, 2004). mailto:parimalbiswas@hotmail.com 84 biswas et al. so to meet the demand of baby corn it is imported from foreign countries like thailand, taiwan etc. and costing about tk. 10 crore per year (bari, 2004). the yield potential of baby corn is greatly influenced by proper method of nitrogen application with proper dose. an increased response to applied nitrogen was observed in baby corn by pandey et al. (2002). increased baby corn production can be achieved by changes of n-fertilizer dose with appropriate application method. optimum rate and time of n application can enhance yield productivity and nutrient use efficiencies while reducing the environmental pollution (neilsen, 2013). the study was therefore, undertaken to find out the yield potentiality of baby corn with nitrogen fertilizer management. materials and methods the experiment was conducted at the agronomy field of sher-e-bangla agricultural university, dhaka during the period from november 2019 to march 2020. the seeds of “baby star” variety of baby corn was used as plant materials and the seeds were collected from khustia seed store, mirpur, dhaka. the seeds were sown on 15 november, 2019 having a spacing of 45 cm x 20 cm. the experiment was laid out in a split-plot design with three replications where four nitrogen dose viz., i) 0 kg n ha-1 (n1), ii) 100 kg n ha-1 (n2), iii) 150 kg n ha-1 (n3) and ii) 200 kg n ha-1 (n4) in the mainplot and three nitrogenous fertilizer application method viz., i) basal (m1), ii) 30 das (m2) and iii) 50% basal + 50% at 30 das (m3) in the sub-plot. the chemical fertilizers i.e., urea as per treatment along with tsp and mop as per recommended dose were used t. the whole amount of all fertilizers except urea was applied as a basla. irrigation water was ensured to the field as and when necessary. two hand weedings were done for all the treatments. the field was infested by different insects and diseases those controlled by applying appropriate ways in time.the immature cobs from harvest area of each plot werecollected and weighed atdifferent dates and finally converted as per hectare basis. yield contributing and other relevant data like plant height at harvest, dry matter plant-1 at harvest, days to tasseling, days to silking, total number of cobs plant-1, cob length, cob diameter, fresh weight of cobs, dehusked cob yield plant-1, husk yield plant-1, number of harvested cobs ha-1 and fresh cob yield ha-1 were collected. statistical analyses were done by using the crop stat computer package and the mean differences among the treatments were compared by least significant difference test at 5 % level of significance. results and discussion plant height the plant height at harvest was significantly differed due to nitrogen dose and interactions of nitrogen dose and application method but insignificant for nitrogen application method (table 1). the maximum t plant height (176.33 cm) was found in 200 kg n ha-1 that similar to 150 and 100 kg n ha-1 whereas no nitrogenous fertilizer application showed the lowest plant height (151.92 cm) that also similar to 100 and 150 kg n ha-1. the increment of plant height was 9.39, 15.40 and 16.07% in 100, 150 and 200 kg n ha-1, respectively as compared to that of control (no nitrogen fertilizer) application. the present investigation corroborates the findings of kar et al. (2006), muniswamy et al. (2007), suryavanshi et al. (2008) and ashok kumar (2009). thakur et al. (1997) observed significant favourable effect of application of 150 200 kg n ha-1 on plant height, functionalleaves plant-1, stem diameter, dry matter plant-1, greenfodder yield, baby corn yield and net returns compared to the lower n levels. the maximum plant height was given by the combination n4m1 (177.80 cm) that similar to all most all other interactions exceptthe lowest plant height (149.33 cm) height in n1m1 that similar to n1m2 (150.93 cm), n1m3 (155.50 cm) and n2m2 (162.07 cm). dry matter weight influence of nitrogen dose and application method on growth 85 the maximum dry matter plant-1 (80.94 g) at harvest was recorded in application of 200 kg n ha-1 that similar to 150 kg n ha-1 (74.33 g) and 150 kg n ha-1 (70.86 g) and the lowest dry matter plant-1 (58.97 g) by no nitrogen application that similar to n2 and n3 (table 1). compared to that of no nitrogen application, the highest dry matter increment for nitrogen was found in n4 (37.26%) that followed by n2 (26.05%) and n3 (20.16%). the highest dry matter plant-1 (98.02 g) was found in n3m3 (split application of 150 kg nha-1) that similar to almost all other interactions except n1m2, n2m3 and n3m1. the lowest dry matter plant-1(41.58 g) was given by n1m2 that similar to almost all other interactions except n2m2, n3m3 and n4m1. days to tasseling and silking the tasseling and silking duration of baby corn was significantly varied for the interaction of nitrogen dose and application method (table 1). the highest duration (79 days) was needed for n1m3 that similar to almost all other interactions except n2m1, n2m3, n3m1, n3m3and n4m3 whereas the lowest duration (75 days) was found in n2m1 that similar to almost all other interactions except n1m2, and n1m3. the highest silking duration (84 days) was found in n1m3 that similar to n2m2 (84 days), n1m1 (83 days) and n1m2 (83 days) whereas the lowest identical duration (81 days) was given by n2m1, n3m1 and n4m3 that similar to almost all other interactions except n1m1, n1m2, n1m3 and n2m2. number of cobs plant-1 there was significant variation observed among different nitrogen doses and interactions for number of cobs plant-1 and the maximum number of cobs plant-1 (2.50) was found in application of 200 kg nha-1 treatment that similar to n3 (2.37) and n2 (2.38) and the lowest number (2.11 plant-1) in control (table 2).higher number of cobs plant-1 (2.91) was found in n4m1 that similar to n2m3 (2.57) and n3m2 (2.55) and the lowest number of cobs plant-1 (1.91) by n1m1 that similar to n1m2 (2.15), n3m1 (2.20), n1m3 (2.26) and n2m2 (2.26). irrespective of nitrogen application methods, the higher doses of nitrogen increased the number of cobs plant-1 that also supported by many researchers. sahoo and mahapatra (2004) reported that increase in the level of npk increased the number of cobs plant-1, weight of whole green cob and yield of green cob significantly. singh and singh (1984) also observed more number of cobs in nitrogen fertilized plots of baby corn mainly due to reduction in per cent of barrenness rather than prolificacy. cob length and cobdiameter there was no significant variation observed among different nitrogen dose and application method for cob length of baby corn though their interactions significantly varied where the highest cob length (9.94 cm) was found in n4m1 that similar to all other interactions except n1m1 (8.11 cm) which showed the lowest cob length that also similar to all other interactions except n4m1 (table 2). cob girth did not show any variations for nitrogen dose, application method and their interactions. table 1. growth parameters of baby corn as affected by nitrogen dose and application method treatments plant height (cm) dry matter (g plant-1) days to tasseling days to silking nitrogen dose (n) n1 n2 n3 n4 151.92 166.18 175.31 176.33 58.97 74.33 70.86 80.94 78 76 76 76 84 82 81 81 lsd(0.05) 23.689 21.435 ns ns 86 biswas et al. nitrogen fertilizer application method (m) m1 m2 m3 167.45 166.62 168.24 71.02 68.15 74.66 76 77 76 82 82 82 lsd(0.05) ns ns ns ns interactions (n x m) n1m1 n1m2 n1m3 n2m1 n2m2 n2m3 n3m1 n3m2 n3m3 n4m1 n4m2 n4m3 149.33 150.93 155.50 170.80 162.07 165.67 171.87 176.33 177.73 177.80 177.13 174.07 66.49 41.58 68.83 81.18 87.48 54.32 46.48 68.07 98.02 89.91 75.46 77.45 76 78 79 75 77 75 76 76 75 77 76 76 83 83 84. 81 84 81 81 82 81 82 81 81 lsd(0.05) 14.46 40.98 2.80 2.64 cv (%) 4.99 33.22 2.12 1.86 n1 = no nitrogen, n2 = 100 kg nha-1, n3 = 150 kg nha-1, n4 = 200 kg nha-1, m1 = basal, m2 = 30 das, m3 = 50% basal + 50% at 30 das fresh weight cob-1 different nitrogen doses and interactions showed significant variation for cob fresh weight of baby corn. the maximum cob fresh weight (41.29 g) was found in application of 200 kg nha-1 treatment (n4) that followedby n2 (38.93 g) and n3 (38.01 g) and the lowest cob fresh weight (31.87 g) in n1 (control) treatment (table2). the fresh cob weight of 200 kg n ha-1 was 43.49% higher compared to that of cob weight in no nitrogen application. higher doses of nitrogen gave higher cob yield of baby corn that also reported by prathyusha and hemalatha (2013).the interaction of nitrogen dose and application method resultedthe maximum cob fresh weight (47.71 g) in n4m1 that similar to n2m1(42.90 g), n4m2(38.84 g) and n2m2& n3m3 (38.56 g) and the lowest cob fresh weight (30.53 g) in n1m1 that similar to n1m2 (32.02 g)and n1m3 (33.07 g). similar higher cob fresh weight of baby corn with higher fertility level was also reported by ghosh et al. (2017). table 2. interaction effect of nitrogen dose and application method on crop characters of baby corn treatments cobs plant-1 (no.) cob length (cm) cob diameter (cm) fresh weight (g cob-1) nitrogen dose (n) n1 n2 n3 n4 2.11 2.38 2.37 2.50 8.28 9.28 8.81 9.26 4.16 4.15 4.02 4.17 31.87 38.97 38.01 45.73 lsd(0.05) 0.36 ns ns 5.69 influence of nitrogen dose and application method on growth 87 nitrogen fertilizer application method (m) m1 m2 m3 2.34 2.32 2.39 9.02 8.89 8.82 4.11 4.13 4.14 43.24 36.63 36.07 lsd(0.05) ns ns ns ns interactions (n x m) n1m1 n1m2 n1m3 n2m1 n2m2 n2m3 n3m1 n3m2 n3m3 n4m1 n4m2 n4m3 1.91 2.15 2.26 2.33 2.26 2.57 2.20 2.55 2.36 2.91 2.34 2.39 8.11 8.53 8.19 9.75 9.04 9.06 8.27 9.07 9.10 9.94 8.94 8.92 4.06 4.16 4.27 4.16 4.14 4.14 3.87 4.13 4.05 4.33 4.07 4.11 30.53 32.02 33.07 43.00 38.56 35.34 38.37 37.10 38.56 61.05 38.84 37.31 lsd(0.05) 0.360 1.68 0.51 9.29 cv (%) 19.40 8.85 12.19 18.93 n1 = no nitrogen, n2 = 100 kg nha-1, n3 = 150 kg nha-1, n4 = 200 kg nha-1, m1 = basal, m2 = 30 das, m3 = 50% basal + 50% at 30 das de-husked cob fresh weight different nitrogen doses, application method and their interactions resulted significant variation for dehusked cob fresh weight. higher t cob weight (9.59 g) was found in application of 200 kg nha-1 treatment (n4) that similar to n2 (8.96 g) and n3 (8.68 g) and the lowest cob fresh weight (7.95 g) incontrol treatment (table3). the fresh weight of dehusked cob at 200 kg n ha-1 was 20.63% higher compared to that of no nitrogen application treatment. parodhanet al. (2007)also reported that highest husked, de-huskedand standard yield of baby corn was obtained with 175 kg nha-1 and it was at par with 125 kg n ha-1. similarly, dadarwaletal. (2009) reported that increasing the rates of npk applicationfrom 120: 40: 30 to 180: 60: 45 kg npk ha-1 significantlyincreased de-husked cob and green fodder yield of baby corn. the highest cob fresh weight (9.46 g) was found in basal application of nitrogen fertilizer (m1) that similar to m2 and the lowest cob fresh weight (8.10 g) in m3 treatment.the highest cob fresh weight (11.74 g) was found in n4m1 and the lowest cob fresh weight (7.38 g) in n1m1that similar to almost all other interactions except n4m1 and n2m1. husk fresh weight cob-1 different nitrogen doses, fertilizer application method and their interactions resulted significant variation for husk fresh weight cob-1 of baby corn. the maximum t husk weight (36.15 g) was found in application of 200 kg nha-1 (n4) that similar to n2 (30.01 g) and the lowest husk weight (23.69 g) incontrol treatment (table 3) that similar to all other treatments except n4. higher green cob as well as green fodder yields at higher level of nitrogen was also reported by bindhaniet al. (2007). the highest husk fresh weight (33.60 g) was found in basal application of nitrogen fertilizer (m1) that similar to m3 and the lowest husk fresh weight (27.81 g) in m2 treatment. the highest husk fresh weight (49.30 g cob-1) was found in n4m1 that differed from all other interactions and the lowest husk fresh weight (22.44 g) in n1m1that similar to almost all other interactions except n4m1. harvested cobs ha-1 88 biswas et al. different nitrogen doses as well as interactions of nitrogen dose and application method resulted significant variation for harvested cobs ha-1. the highest number of cobs ha-1 (196524) was found in application of 100 kg nha-1 treatment (n2) that similar to n4 (193808) and n3 (182451) and the lowest number of cobs ha-1 (172082) in n1 (control) treatment (table 3). table 3. interaction effect of nitrogen dose and application method on yield and other crop characters of baby corn treatments de-huskedcob fresh weight (g cob-1) husk fresh weight (g cob-1) harvested cobs (no. ha-1) cob fresh yield (kg ha-1) nitrogen dose (n) n1 n2 n3 n4 7.95 8.96 8.68 9.59 23.69 30.01 29.33 36.15 172082 196524 182451 193808 6924.71 7315.21 7265.40 7016.40 lsd(0.05) 1.623 6.548 17432.35 ns nitrogen fertilizer application method (m) m1 m2 m3 9.46 8.82 8.10 33.60 27.81 27.97 179797 188870 189981 6742.74 7431.16 7217.39 lsd(0.05) 0.99 5.75 ns ns interactions (n x m) n1m1 n1m2 n1m3 n2m1 n2m2 n2m3 n3m1 n3m2 n3m3 n4m1 n4m2 n4m3 7.38 8.53 7.94 9.69 8.55 8.64 9.01 8.89 8.13 11.74 9.32 7.69 22.44 23.49 25.13 33.31 30.01 26.70 29.35 28.20 30.43 49.30 29.52 29.61 157021 175538 183685 187389 183685 218497 162947 203683 180723 211831 192573 177019 6135.83 7104.10 7504.34 7219.22 7408.14 7318.26 7450.25 7479.97 6865.98 6165.68 7732.41 7180.96 lsd(0.05) 1.97 11.49 36962.60 1527.68 cv (%) 12.97 22.29 11.47 12.38 n1 = no nitrogen, n2 = 100 kg nha-1, n3 = 150 kg nha-1, n4 = 200 kg nha-1, m1 = basal, m2 = 30 das, m3 = 50% basal + 50% at 30 das higher green cob as well as green fodder yields at higher level of nitrogen was also reported by bindhaniet al. (2007). the highest number of cobs ha-1 (218497) was found in n2m3 that similar to n4m1 (211831), n3m2 (203683), n4m2 (192573), n2m1 (187389), n2m2 (183685) and n1m3 (183685). the lowest number of cobs ha-1 (157021) found in n1m1that similar to almost all other interactions except n2m3, n3m2 and n4m1. fresh cob yield different nitrogen doses and application method showed non-significant variation for fresh cob yield ha-1 of baby corn but their interactions was found significant. the highest cob yield ha-1 (7732.41 kg) was found in n4m2 that similar to all other interactions except n1m1 and n4m1 andthe lowest fresh cob yield ha-1 (6135.83 kg) found in interaction of n1m1that similar to all other interactions except n4m2. conclusion influence of nitrogen dose and application method on growth 89 based on the results of the study it may be concluded that baby corn can be successfully cultivate in bangladesh. increment of nitrogen dose increased the fresh cob weight of baby corn but the number remain unchanged. nitrogen fertilizer application method had no remarkable impact on cob yield. application of 200 kg n ha-1 as basal dose or 150 kg n ha-1having 50% as basal dose and rest 50% as side dressing at 30 days after sowing might be recommended for baby corn cultivation.however, to reach a specific conclusion and recommendation experiments with different levels of other fertilizers and with more varieties should be repeated in different agro-ecological zones. acknowledgement the author acknowledged the ministry of science and technology, govt. of the people’s republic of bangladesh for providing financial support to conduct the study. references ashok kumar. 2008. productivity, economics and nitrogenuse efficiency of specialty corn (zea mays) as influenced by planting density and nitrogen fertilization. indian j. agron. 53(4): 306-309. ahmed, f. 1994. maize production technology (in bengali). international fertilizer development center (ifdc) – consultant of ministry of agriculture, bangladesh. bakshi, m.p.s. and m. wadhwa. 2012. nutritional evaluation of baby corn husk-a new feed resource for livestock. indian j. anim. sci. 82: 1548-50. bakshi, m.p.s., m. wadhwa and h.p.s. makkar. 2016. wastes to worth: vegetable wastes and by-products as animal feed. commonwealth agric. bureau rev. 11: no. 012. bari (bangladesh agriculture research institute). 2004. production technology of baby corn(in bengali). agronomy division, bari, joydebpur, bangladesh. bindhani, a., k.c. barik, l.m. garnayak and p.k. mahapatra. 2007. nitrogen management in baby corn (zea mays l.). indian. j. agron. 52: 135-138. bar-zur, a. and h. saadi. 1990. prolific maize hybrids for corn. j. hort. sci.65: 97-100. dadarwal, r.s., n.k. jain and d. singh. 2009. integrated nutrientmanagementin baby corn (zea mays). indian j. agric. sci.79(12): 1023-1025. das, s., v.k. yadav, jat, k. asha, r. sujay, k. joyti and j.c. sekhar. 2008. babycorn in india. dmt technical bulletin. directorate of maize research, pusa campus, new delhi: 1-45. ghosh, m., s.k. maity, s.k. gupta and a.r. chowdhury. 2017. performance of baby corn under different plant densities and fertility levels in lateritic soils of eastern india, int. j. pure app. biosci. 5(3):696-702. doi: http://dx.doi.org/10.18782/2320-7051.5012. kar, p.p., k.c. barik, p.k. mahapatra, l.m. garnayak, b.s. rath, d.k. bastia and c.m. khanda. 2006. effect of planting geometry and nitrogen on yield, economics and nitrogen uptake of sweet corn (zea mays). indian j. agron. 51(1): 43-45. muniswamy, s., r.gowda and s.r. prasad. 2007. effect of spacing and nitrogen levels on seed yield and quality of maize single cross hybrid pehm-2. mysore j. agric. sci. 41(2): 186-190. nielsen, r.b. 2013. root development in young corn, in: purdue university department of agronomy. pandey, a.k., v.p. moni, v. prakash, r.d.singh and h.s. gupta. 2002. effect of varieties and plant densities on yield, yield attributes and economics of baby corn (zea mays). indian j. agron. 47: 221-226. parodhan, r.s., s. bala and p. khoyumthem. 2007. response torate of nitrogen and effect of rate of nitrogen and effect of plant density on yield of baby corn. j. intercad. 11(3): 265-269. prathyusha, c. and s. hemalatha. 2013. yield and economics of specialty corn at various levels of nitrogen application under pongamia + maize agri-silvy system. intl. j. adv. res. 1(6): 476-481. 90 biswas et al. ramchandrappa, b.k., i.i.v. nangappa and i.i.k. shiva kumar. 2004. yield and quality of babycorn (zea mays l.) as influenced by spacing and fertilizer levels. acta agron.hungarica. 52: 237-243. http://dx.doi.org/10.1556/aagr.52.2004.3.4. sahoo, s.c. and p.k. mahapatra. 2004. response of sweet corn (zea mays) to nitrogen levels and plant population. indian j. agric. sci. 74(6): 337-338. salahuddin, m. and n.a. ivy. 2003. cultivation of maize. production and uses of maize in bangladesh. pp.29-35. singh, n.b. and p.p. singh. 1984. effect of intercropping with legumes on grain yield of maize and its residual effect on succeeding wheat. indian j. agron. 29: 295-298. suryavanshi, v.p., b.n. chavan, k.t. jadhav and p.a. pagar. 2008. effect of spacing, nitrogen and phosphorous levels on growth, yield and economics of kharif maize. intl. j. trop. agric. 26(34): 287-291. thakur, d.r., o. prasad, p.c.kharwara and s.k. bhalla. 1997. effect of nitrogen and plant spacing on growth, development and yield of baby corn. indian j. agron. 42(3): 479-483. thakur, d.r., v. sharma and s.r. pathik. 2000. evaluation of maize (zea maysl) cultivars for their suitability baby corn under mid-hills of north-western himalayan. india j. agril. sci. 70: 146-148. http://dx.doi.org/10.1556/aagr.52.2004.3.4 bangladesh agron. j. 2022, 25(1): 91-96 intercropping spinach and red amaranth with brinjal under different planting system m.z. ali, a.a. begum, s.s. kakon, m.r. karim and d.a. choudhury agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh corresponding e-mail: zabiedbd@yahoo.com (received: 18 may 2022, accepted: 05 july 2022) keywords: intercropping, brinjal, spinach, red amaranth, yield and cost-benefit abstract the experiment was conducted at agronomy research field of bangladesh agricultural research institute, gazipur, during the rabi season of 2018 to 2019 and 2019 to 2020 to find out the suitable crop combination of spinach (spinacia oleracea) and red amaranth (amaranthus cruentus) with brinjal (solanum melongena) for higher brinjal equivalent yield, monetary advantage and maximize land utilization through intercropping system. treatments were: t1 = 2 rows spinach (50%) in between two rows of brinjal (100%), t2 = 3 rows spinach (75%) in between two rows of brinjal (100%), t3 = 2 rows red amaranth (50%) in between two rows of brinjal (100%), t4 = 3 rows red amaranth (75%) in between two rows of brinjal (100%), t5 = sole brinjal ( 80 cm × 60 cm), t6 = sole spinach (line to line 20 cm) and t7 = sole red amaranth (line to line 20 cm) were used in the study. all the intercropping combinations showed better performance in terms of brinjal equivalent yield, gross return and benefit cost ratio (bcr) over sole crops. among the intercropping combinations, 3 row spinach (75%) in between two rows of brinjal (100%) was the most feasible and profitable intercropping system in respect of brinjal equivalent yield (34.72 t ha-1), land equivalent ratio (1.57), gross return (tk. 6,94,346 ha1), gross margin (tk. 4,59,088 ha-1) and benefit cost ratio (2.95). from the two years, results revealed that all intercropping treatments were productive as compared to sole treatments but 3 rows spinach (line to line 20 cm) 75% in between two rows of brinjal (80 cm × 60 cm) 100% intercropped combination might be agronomically feasible and economically profitable. introduction intercropping is a traditional practice in bangladesh and it increases total productivity per unit area through maximum utilization of land, labour, and growth resources (ahmed et al., 2013; islam et al., 2006; mahfuza et al., 2012). by judicious choice of compatible crops and adopting appropriate planting geometry, inter/intraspecific competition may be minimized resulting in higher total productivity (alom et al., 2013). canopy architecture of tall stature crop regulates the availability of light on under storied crop (faruque et al., 2006). in bangladesh, small farmers constitute 79.4% of our farming community and their cultivated lands are shrinking day by day (moa, 2014). in that context, intercropping is one of the viable technologies to ensure the efficient utilization of their resources for increased production and family income. intercropping offers the possibility of yield advantage relative to sole cropping through yield stability and improved yield in tropical and sub-tropical areas (nazir et al., 2002; malik et al., 2002; bhatti et al., 2005). brinjal (solanum melongena) is an important vegetable crop is cultivated round the year throughout the country in bangladesh. it is a tall structure, long duration (140-180 days), and wide spaced (80 cm × 60 cm) crop. so, there is a great scope to cultivate short duration (30-45 days) leafy vegetables like red amaranth, and spinach in the inter row space of brinjal as intercrop. leafy vegetables like red amaranth and spinach being short structure quick growing crops can be easily intercropped between two rows of brinjal at early growth stage for mailto:zabiedbd@yahoo.com 92 ali et al. getting the higher economic returns. the nutritive value of red amaranth lies in their content of β-carotene (precursor of vitamin a) and vitamin c. it contains carotene (11.94 mg), vitamin c (43 mg), calcium (374 mg), carbohydrate (5.0 g), protein (5.3 g), fat (0.1 g) and calories (43 k cal.) 100 g-1 of an edible portion (begum, 2000). spinach (spinacia oleracea) is a greenleafy vegetable that belongs to the family amaranthaceae. it is often recognized as one of the functional foods for its wholesome nutritional, antioxidants, and anti-cancer composition. the major micronutrients in spinach are vitamins a (from â-carotene), c, k, and folate, and the minerals, calcium, iron, and potassium. spinach also provides fiber and is low in calories. its tender, crispy, dark green leaves are one of the favorite ingredients of chefs all around the world. spinach vegetables are also valuable in maintaining the alkaline reserve of the body. they are valued mainly for high protein (2.9 g), calcium (30 mg), iron (0.81 g), magnesium (24 mg), potassium (167 g), carbohydrate (3.6 g), vitamin, fiber (2.2 g), and mineral contents (rumeza et al., 2006). however, the literature regarding spinach-brinjal and red amaranthbrinjal intercropping is very scarce. keeping this view in mind, the experiment was conducted to find out the suitable crop combination of spinach and red amaranth with brinjal for increasing total productivity, economic return and maximize land utilization through an intercropping system. materials and methods a field experiment was conducted at agronomy research field of bangladesh agricultural research institute, joydebpur, gazipur, during the rabi season of 2018 2019 and 2019 2020. the soil was silty clay loam with ph 6.3 belonging to agro ecological zone (aez) 28. the treatments were: t1 = 2 rows spinach (50%) in between two rows of brinjal (100%), t2 = 3 rows spinach (75%) in between two rows of brinjal (100%), t3 = 2 rows red amaranth (50%) in between two rows of brinjal (100%), t4 = 3 rows red amaranth (75%) in between two rows of brinjal (100%), t5 = sole brinjal ( 80 cm × 60 cm), t6 = sole spinach (line to line 20 cm) and t7 = sole red amaranth (line to line 20 cm). the trial was set up in a randomized complete block design with three replications. the unit plot size was 4.2 m × 3.2 m. the sole crop of brinjal and intercropped treatments were fertilized with cow dung @ 5 t/ha and 12031-120-13-3-1.5 kg/ha of n-p-k-s-zn-b in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate, and boric acid, respectively. for sole brinjal and intercrop, full amount of all other fertilizer except n and k were applied in the pit before one week of transplanting brinjal. n and k were applied in three equal splits at 21, 40, and 60 days after transplanting (dat) of brinjal as ring method followed by irrigation. sole spinach fertilized with 50-13-18-5 kg/ha of n-p-k-s. half n and all other fertilizers were applied at the time of final land preparation and the rest n was applied at 10 days after emergence (dae) of spinach. sole red amaranth fertilized with 78-18-35-4 kg/ha of n-p-ks. half n and all other fertilizers were applied at the time of final land preparation and the rest n was applied at 10 dae of red amaranth (frg, 2018). brinjal (var. bari begun-8) as main crop and red amaranth (var. bari lalshak-1) and spinach (var. bari spinach-1) were used as intercrops in this study. the sole crop of brinjal was planted at a spacing of 80 cm × 60 cm. after the establishment of brinjal seedling (12 days after transplanting) spinach and red amaranth seeds were sown as per treatments. brinjal (thirty-days-old seedling) was transplanted on 29 november, 2018 and 10 december 2019. seed of spinach and red amaranth sown on 11 december, 2018 and 23 december, 2019. brinjal was harvested four times and it was harvested in 2019 on 04 march, 11 march, 18 march, 29 march and in 2020 harvested on 03 april, 13 april, 21 april, and 2 may. both spinach and red amaranth were harvested on 13 january, 2019 and 27 january, 2020. four irrigations were done in the experimental field. first irrigation was applied just after transplanting (brinjal) and sowing of the component crops for proper germination. second, third and fourth irrigation was applied at 45, 60, and 90 days after transplanting (dat) of brinjal. weeding was done as per requirement. sex pheromone trap was used for controlling of brinjal shoot and fruit borer from active vegetative stage up to fruit developing stage. yield and yield contributing characters were recorded and pooled data analyzed statistically and means separations were done by lsd test at a 5% level of significance. brinjal http://www.scialert.net/asci/result.php?searchin=keywords&cat=&ascicat=all&submit=search&keyword=nutritive+value http://www.scialert.net/asci/result.php?searchin=keywords&cat=&ascicat=all&submit=search&keyword=vitamin+a http://www.scialert.net/asci/result.php?searchin=keywords&cat=&ascicat=all&submit=search&keyword=vitamin+c http://www.scialert.net/asci/result.php?searchin=keywords&cat=&ascicat=all&submit=search&keyword=vitamin+c http://www.scialert.net/asci/result.php?searchin=keywords&cat=&ascicat=all&submit=search&keyword=vitamin+c https://scialert.net/fulltext/?doi=pjbs.2003.2044.2049#38030_b intercropping spinach and red amaranth with brinjal 93 equivalent yield (bey) was converted by converting yield of intercrops on the basis of the market price of the individual crop following the formula islam et al. (2012): bey = yield of intercrop brinjal + brinjalof price piyi × where, yi = yield of intercrops (spinach/ red amaranth) and pi = price of intercrop (spinach/ red amaranth). land equivalent ratio (ler) values were determined from the yield data of the crops according to mian (2008). ler = rsy riy bsy biy  where, biy = intercrop yield of brinjal bsy = sole crop yield of brinjal riy = intercrop yield of component crops (spinach/ red amaranth). rsy = sole crop yield of component crops (spinach/ red amaranth). results and discussion yield and yield contributing characters of brinjal plant height, number of fruits plant-1, single fruit weight, fruit length, fruit diameter, and yield of brinjal (t ha-1) was significantly influenced by intercropping (table 1). the maximum plant height of 102.79 cm was obtained from t5 treatment (sole brinjal) which was statistically similar to that of t3 (101.84cm), t4 (98.40 cm), and t1 (97.60 cm) treatments and the lowest plant height 96.78 cm from t2 treatment. table 1. fruit yield and yield attributes of brinjal under sole and intercropping system. treatment plant height (cm.) number of fruits plant-1 single fruit weight (g) fruit length (cm) fruit diameter (cm.) fruit yield (t ha-1) t1 97.60 25.53 86.86 20.88 4.32 19.44 t2 96.78 24.37 86.34 19.47 4.12 18.39 t3 101.84 27.36 91.01 23.38 4.77 20.81 t4 98.40 26.31 89.67 21.98 4.50 19.80 t5 102.79 29.93 96.10 25.27 4.95 21.21 lsd(0.05) 8.49 3.49 7.26 2.64 0.45 2.99 cv (%) 4.53 6.94 4.28 6.31 5.22 7.96 note: t1 = 2 rows spinach (50%) in between two rows of brinjal (100%), t2 = 3 rows spinach (75%) in between two rows of brinjal (100%), t3 = 2 rows red amaranth (50%) in between two rows of brinjal (100%), t4 = 3 rows red amaranth (75%) in between two rows of brinjal (100%), t5 = sole brinjal (80 cm × 60 cm), t6 = sole spinach (line to line 20 cm) and t7 = sole red amaranth (line to line 20 cm). among the intercropping combinations, the maximum number of fruits plant-1 (27.36), the highest single fruit weight (91.01 g), fruit length (23.38 cm), and fruit diameter (4.77 cm) were recorded in t3 treatment which followed by t4 and t1 treatments and the minimum number of fruits plant-1 (24.37), lowest single fruit weight (86.34 g), fruit length (19.47 cm), and fruit diameter (4.12 cm) were recorded in t2 treatment. the maximum brinjal fruit yield (21.21 t ha-1) was obtained from t5 treatment (sole brinjal) which was statistically similar with t3 (20.81 t ha-1), t4 (19.80 t ha-1) and t1 (19.44 t ha-1) treatments and the lowest (18.39 t ha-1) in t2 treatment. under intercropping, the maximum fruit yield (20.81 t ha-1) was recorded in t3 treatment (2 rows red amaranth 50% in between two rows of brinjal 100%) and the lowest fruit yield (18.39 t ha-1) in t2 treatment (3 rows spinach 75% in between two 94 ali et al. rows of brinjal 100%). the higher fruit yield in the sole crop was attributed due to more number of fruit plant-1 and higher single fruit weight. islam et al. (2014) also reported a similar result. yield of spinach and red amaranth the yield of spinach and red amaranth was significantly influenced by intercrop spinach and red amaranth with brinjal (figure 1). the higher spinach yield (31.93 t ha-1) and red amaranth yield (22.62 t ha-1) were recorded in sole spinach and sole red amaranth. among the intercropping combinations, the higher spinach yield (22.47 t ha-1) was recorded in t2 treatment (3 rows spinach 75% in between two rows of brinjal 100%) and the lowest spinach yield (15.89 t ha-1) from t1 treatment (2 rows spinach 50% in between two rows of brinjal 100%). in the case of red amaranth, a similar trend was also observed. higher red amaranth biomass yield (14.96 t ha-1) was recorded in t4 treatment (3 rows red amaranth 75% in between two rows of brinjal 100%) and the lowest red amaranth yield (11.61 t ha-1) from t3 treatment (2 rows red amaranth 50% in between two rows of brinjal 100%). faruque et al. (2006) also reported a similar result. fig. 1. green biomass yield of spinach and red amaranth under sole and intercropping system (lsd0.05 = 2.71). brinjal equivalent yield (bey) brinjal equivalent yield expressed total productivity. brinjal equivalent yield was higher in all the intercrops (27.20 to 34.72 t ha-1) than the sole crop of brinjal 22.08 t ha-1 (table 2). in intercrop combination, the maximum brinjal equivalent yield (34.72 t ha-1) was recorded in t2 treatment which was followed by t4 treatment (31.57 t ha-1). the lowest brinjal equivalent yield (27.20 t ha-1) was obtained from t3 treatment over the sole brinjal. total productivity also increased by 57.23, 43.00, 33.39, and 23.21% at t2, t4, t1 and t3 treatments, respectively. ahmed et al. (2013) also reported that intercrop combination increases the equivalent yield. land equivalent ratio (ler) the maximum land equivalent ratio (1.57) was recorded in t2 treatment (3 rows spinach (75%) in between two rows of brinjal 100%) followed by t4 treatment 1.43 (3 rows red amaranth (75%) in between two rows of brinjal 100%) (table 3). the ler of different crop combinations ranged from 1.23 to 1.57% indicating that land utilization was increased 23 to 57% by intercropping. the mean values of ler (more than one) in all intercropping treatments revealed that land was more efficiently utilized under intercropping than under sole cropping of brinjal, spinach, and red amaranth. nazir et al. (2002) also reported that intercrop combinations always increases the land equivalent ratio (ler). intercropping spinach and red amaranth with brinjal 95 table 2. brinjal equivalent yield (bey), land equivalent ratio (ler) and % increase of bey over sole brinjal in brinjal + spinach/ red amaranth intercropping system. treatment bey (t ha-1) ler % increase of bey over sole brinjal t1 29.45 1.33 33.39 t2 34.72 1.57 57.23 t3 27.20 1.23 23.21 t4 31.57 1.43 43.00 t5 22.08 1.00 note: t1 = 2 rows spinach (50%) in between two rows of brinjal (100%), t2 = 3 rows spinach (75%) in between two rows of brinjal (100%), t3 = 2 rows red amaranth (50%) in between two rows of brinjal (100%), t4 = 3 rows red amaranth (75%) in between two rows of brinjal (100%), t5 = sole brinjal (80 cm × 60 cm), t6 = sole spinach (line to line 20 cm) and t7 = sole red amaranth (line to line 20 cm). cost and return analysis intercropping combination of spinach and red amaranth with brinjal showed higher monetary return than sole crop (table 3). among the intercropping situation, the highest gross return (tk. 6,94,346 ha-1) was recorded from t2 treatment (3 rows spinach (75%) in between two rows of brinjal 100%). this intercropping combination also gave the highest gross margin (tk. 4,59,088 ha-1) and benefit cost ratio (2.95). the results of increased productivity and returns were consistent with the earlier reports of yield advantage of crop mixture compared to monoculture (akhteruzzaman and quayyum,1991, islam et al., 2012 and ahmed et al., 2013). table 3. costbenefit analysis of brinjal, spinach and red amaranth under sole and intercropping situation. treatment gross return (tk ha-1) cost of production (tk ha-1) gross margin (tk ha-1) benefit cost ratio (bcr) t1 5,89,049 2,34,058 3,54,991 2.52 t2 6,94,346 2,35,258 4,59,088 2.95 t3 5,44,083 2,32,789 3,11,294 2.34 t4 6,31,488 2,33,289 3,98,199 2.71 t5 4,41,533 1,98,851 2,42,682 2.22 price: brinjal: tk. 20/kg, red amaranth: tk. 15/kg, spinach: tk. 15/kg note: t1 = 2 rows spinach (50%) in between two rows of brinjal (100%), t2 = 3 rows spinach (75%) in between two rows of brinjal (100%), t3 = 2 rows red amaranth (50%) in between two rows of brinjal (100%), t4 = 3 rows red amaranth (75%) in between two rows of brinjal (100%), t5 = sole brinjal (80 cm × 60 cm), t6 = sole spinach (line to line 20 cm) and t7 = sole red amaranth (line to line 20 cm). conclusion from the two years results revealed that all intercropping treatments were productive as compared to sole treatments but 3 rows spinach (line to line 20 cm) 75% in between two rows of brinjal (80 cm × 60 cm) 100% intercropped combination might be agronomically feasible and economically profitable. references ahmed, f., m.n. islam, m.s. alom, m.a.i. sarker and m.a. mannaf. 2013. study on intercropping leafy vegetables with okra (abelmoschus esculentus l.). bangladesh j. agril. res. 38(1): 137-143. akhteruzzaman, m. and m.a. quayyum. 1991. intercropping of maize with three varieties of groundnut at two levels of plant population. bangladesh j. agric. sci. 18(1): 39-44. alom, m.s., b.l. nag, m.n. islam, f. ahmed and s. akter. 2013. performance of different crop species with pointed gourd (trichosanthe sdioica roxb.). bangladesh j. agric. res. 38(3): 523-529. begum, m.n. 2000. swastha-pusti babosthapona. 1st edn. bangla academy, dhaka, p.138. 96 ali et al. bhatti, i.h. 2005. agro-physiological studies on sesame-legume intercropping system in different geometric arrangements. ph. d. thesis, department of agronomy university of agriculture faisalabad, pakistan. faruque, a., m.a. rahaman, m.a.h.s. jahan, m. ahmed and m.a. khayer. 2006. effect of different planting systems in maize/ spinach-red amaranth intercropping. bangladesh j. agric. environ. 2(2): 69-76. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council (barc), new airport road, farm gate, dhaka-1215. pp.99-102. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effect on the physiological attributes and productivity of maize-bushbean intercropping system. bangladesh j. agril. res. 31(3): 353-364. islam, m.r., m.a.k. mian and m.t. rahman. 2012. suitability of intercropping sesame with mukhikachu. bangladesh j. agril. res. 37(4): 625-634. islam, m.r.., m.t. rahman, m.f. hossain and n. ara. 2014. feasibility of intercropping leafy vegetables and legumes with brinjal. bangladesh j. agric. res. 39(4): 685-692. mahfuza, s.n., m.n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping different vegetables and spices with pointed gourd. j. expt. biosci. 3(1): 77-82. malik, m.a., m.f. saleem, m. sana and a. aziz. 2002. agro economic expression of different relay crops after rice harvest under conventional and zero tillage. int. j. agric. biol. 4: 277-278. mian, m.a.k. 2008. performance of maize oriented cropping patterns under different nutrient management. ph. d. dissertation. dept. agron. bangladesh agril. univ., mymensingh. pp.31-137. moa (ministry of agriculture). 2014. hand book of agricultural statistics, december 2007. government of the peoples republic of bangladesh. http://www.moa.gov.bd/ statistics/ statistics.htm. nazir, m.s., a. jabbar, i. ahmad, s. nawaz and i.h. bhatti. 2002. production potential and economics of intercropping in autumn-planted sugarcane. int. j. agric. biol. 4: 140-142. rumeza h., i. zafar, m. iqbal, h. shaheena and r. masooma. 2006. use of vegetables as nutritional food: role in human health. j. agric. biol. sci. 1(1): 18-22. http://www.moa.gov.bd/ microsoft word baj 357c__press bangladesh agron. j. 2020, 23(1): 67-73 quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh: agronomic performance with sowing date p.k. biswas1 and z.a. tanni2 1department of agronomy, sher-e-bangla agricultural university, dhaka 2ist, sher-e-bangla agricultural university, dhaka corresponding e-mail: parimalbiswas@hotmail.com (received: 27 may 2020, accepted: 24 august, 2020) keywords: bangladesh, quinoa, optimum sowing date, yield, nutrition abstract the experiment was conducted at sher-e-bangla agricultural university, dhaka with the financial support of saures (sher-e-bangla agricultural university research system) to study the possibility of growing quinoa in bangladesh with different sowing dates having two cultivars. the experiment comprised of two factors; factor a: cultivar (2) viz., titicaca (c1) and vikinga (c2) and factor b: sowing date (5) viz. november -10 (s1), december -10 (s2), january -10 (s3), february -10 (s4) and march -10(s5). the experiment was laid out in split-plot design with three replications. results revealed that different growth parameters, yield attributes and yield were significantly varied with different sowing dates. at harvest, the tallest plant height (63.75 cm), highest seed yield (0.77 t ha-1) and straw yield (0.89 t ha-1) was found from titicaca but the higher number of branches plant-1 (17.71) from vikinga. the tallest plant height (62.54 cm), highest branch number plant-1 (22.82), longest inflorescence (29.62 cm), highest 1000-seed weight (2.56 g), seed yield (1.09 t ha-1), straw yield (1.25 t ha-1) and harvest index (46.58%) was exhibited by november -10 sowing. the interaction effect of titicaca sown in november -10 (c1s1) resulted the highest plant height at harvest (72.83 cm), branches plant-1 (25.20), 1000-seed weight (2.58 g), seed yield (1.16 t ha-1) and straw yield (1.33 t ha-1) but the highest inflorescence length (31.46 cm) and harvest index (47.02%) from c2s2 (vikinga sown in december – 10). from the above results it can be concluded that quinoa – as a new crop is suitable to cultivate in rabi season of bangladesh with a complete agronomic management package. introduction quinoa (chenopodium quinoa willd.) is a yearly herbaceous plant belongs to amaranthaceae family that originated in the appeasing slopes of the andes in south america. it was cultivated and worn by the inca (ruling class) people since 5,000 b.c. it is obsessive in broad diversity of forms i.e., grains, flakes, pasta, bread, biscuits, beverages, meals etc. quinoa is revealed as a strength rations by north americans and europeans in the 1970‟s and its reputation is dramatically increased in recent years because it is gluten-free (helpful for diabetic patients) and high in protein. in 2018, world production of quinoa was 158,920 tonnes, led by peru and bolivia with 99% of the total combined (faostat, 2020). quinoa is a quick-rising plant, grows up to 2 m tall with exchange, thickly ragged, triangular to ovate vegetation. every inflorescence produced hundreds of little achiness, approximately 2 mm in width. quinoa is an achene (a seed-similar to fruit with a firm fur) with diversified colours quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh 67 ranging from white or pale yellow to orange, red, brown and black. an ideal average temperature for quinoa would be around 15–20°c, but some specific landraces can also withstand extreme temperatures from −8°c to +38°c (bazile et al., 2015). quinoa grain is the only vegetable food that provides all amino acids fundamental to the life of humans in most favorable quantities and is comparable with milk. the crop is rich in protein (7.47 to 22.08%) with higher concentration of lycine, isoleucine, methionine, histidine, cystine and glycine. the ash substance is 3.4 per cent containing high amount of ca, fe, zn, cu and mn. the oil content is 1.8 to 9.5 per cent and loaded in necessary fatty acids like linoleate and linolenate. in adding up, quinoa seed is wealthy in thiamine (0.4 mg), folic acid (78.1 mg), vitamin c (16.4 mg), riboflavin (0.39 mg) and carotene (0.39 mg) in 100 g seed, respectively. the calorific assessment is 350 cal per 100 g grains and is bigger than that of additional cereal and legume foods and its glycemic index is 53 which is much lower than white rice. the digest ability of quinoa protein is more than 80 per cent. quinoa also have usual defiant oxidants like α-tocopheral (5.3 mg), γ-tocopheral (2.6 mg) in 100 g seed and phytoestrogens that avoid regular diseases such as osteoporosis, breast cancer, heart diseases and additional feminine troubles caused by require of estrogen during the menopause. fao declared 2013 as international year of quinoa (bhargava et al., 2006). the importance of quinoa is getting momentum around the world due to its ability to withstand in extreme conditions (bazile et al., 2015). the high genetic diversity of the crop provides its opportunities for leveraging its hardiness and further wide adaptation (louafi et al., 2013). today, drought and soil salinization are major limiting factors in cultivation, a fact that is generating significant pressure on arable land availability. considering these major challenges, the crop is presently cultivated, or is under experimentation, in more than 95 countries and its cultivation continue to expand rapidly worldwide (bazile, 2014; bazile et al., 2016). the cultivation of quinoa spreading throughout the world as far as tibet, morocco, france, india, china, the united kingdom, sweden, denmark, netherlands, canada, usa, australia, thailand, kenya and italy, among others (bhargava et al., 2006; pulvento et al., 2010; bazile et al., 2015). a balanced diet, adequate in all necessary nutrients; energy, protein, vitamins and minerals, can satisfy both perceptible and hidden hunger (jahan and hossain, 1998). though rice as a cereal is the main food of bangladesh, it is not well balanced and as a result children and women suffer from high levels of malnutrition and micronutrient deficiencies such as low birth weight, undernutrition, vitamin a deficiency, iodine-deficiency disorders and iron-deficiency anaemia. at the same time, new health problems related to over-nutrition such as obesity are emerging (world bank, 2005). optimum planting time is the first step and measured as a base that leads to growth of appropriate manufacture technology particularly for a new-fangled crop in a particular area (sajjad et al., 2014). there is no research has yet been conducted to introduce quinoa in bangladesh. hence it is high time to introduce the crop like quinoa in bangladesh to supplement for the malnutrition facing by the country people’s. therefore the experiment was undertaken during rabi season taking two danish cultivars and different dates of sowing to identify the optimum sowing date of quinoa for the prevailing climatic condition of bangladesh. materials and methods the experiment was conducted at the agronomy farm of sher-e-bangla agricultural university (sau), dhaka that located in 23°77' n latitude and 90.26o e longitudes during november, 2017 to july, 2018. the general soil type of the experimental field was deep red brown terrace 68 biswas and tanni soil belongs to the tejgaon series under the agroecological zone, madhupur tract (aez-28). the soil was consuming a texture of silty clay with ph 5.6 and organic matter 0.78%, sand 26%, silt 45% and clay 29%. during the experimental period the maximum temperature (39.4oc), highest relative humidity (78%) and highest rainfall (277 mm) and the minimum temperature (17oc) and minimum relative humidity (64%) was recorded. the experiment comprised of two factors; factor a: cultivar (2) titicaca (c1) and vikinga (c2), factor b: sowing dates (5) november -10 (s1), december -10 (s2), january -10 (s3), february -10 (s4) and march -10 (s5). two danish cultivars e.g., titicaca and vikinga was collected from dae, bangladesh. initially the experiment was designed with a sowing date of each month but finally the plants of april and may sowing were damaged and june to october sowing were not possible due to excessive soil moisture. the land was opened on the 05 november, 2017. urea, triple super phosphate (tsp) and muriate of potash (mop) @180, 152 and 63 kg ha-1 were added in the experimental soil as a source of nitrogen (n), phosphorous (p) and potassium (k), respectively. full dose of tsp and mop along with one third urea were applied in final land preparation as basal dose and the rest amount of urea was top dressed at 25 and 40 das (risi and nicholas, 1991). the experiment was laid out in a split-plot design with three replications where cultivars were assigned in the main plot and sowing dates in sub-plot. the first sowing was done on november -10, 2017 in solid rows in the furrows having a depth of 2-3 cm and row to row distance was 30 cm. other seed sowing were done as per treatment. thinning was done two times; first at 10 das and second at 15 das to maintain optimum plant population in each plot. irrigation was given at 15 and 30 das for optimizing the vegetative growth for all experimental plots equally and supplementary irrigation was maintained as and when necessary. proper drainage facilities was also maintained accurately to remove excess water from the experimental plot. the field was weeded twice at 20 and 35 das by hand weeding. five plants from each plot were randomly selected and marked with sample card from which plant height and branches plant-1 were recorded at different growth stages. length of inflorescences plant-1, 1000-seed weight, seed and straw yield were recorded at harvest. harvesting was done when 90% of the grain became green to yellow (titicaca) and red (vikinga) in color. the matured crops were collected by hand picking from each plot. the collected crops were sun dried, threshed and the seeds were separated, cleaned and dried in the sun for 3 to 5 consecutive days for achieving safe moisture of seed. the dried seeds and straw were cleaned and weighed. the collected data were compiled and analyzed statistically using the analysis of variance (anova) technique with the help of cropstat and the mean differences were adjudged by least significant difference (lsd) test at 5% level of significance (gomez and gomez, 1984). results and discussion effect of cultivar plant height at 15 das showed non-significant variation for different cultivars but at 30 das and harvest significant variation was observed (table 1). at 30 das, the higher plant height (57.55 cm) was obtained from titicaca and the lower (44.37 cm) from vikinga. similar trend was also followed at harvest with higher plant height (63.75 cm) of titicaca compared to that of vikinga (50.62 cm). the plant height of titicaca at harvest was 20.58% higher than vikinga. such higher plant height of titicaca might be due to its genetical character. the result was similar with the findings of fernando et al. (2012) who conducted a research on quinoa cultivars viz. titicaca and vikinga and found higher plant height from titicaca. branches plant-1 at 30 das and harvest showed significant variation for cultivars but non-significant at 15 das (table1). the higher number of branches plant-1 (16.11 and 17.11) was obtained from vikinga quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh 69 compared to titicaca (15.05 and 16.59) at 30 das and harvest, respectively. inflorescence length and 1000-seed weight showed non-significant variation for cultivars. seed yield of quinoa showed significant variation for cultivars. the higher seed yield (0.77 t ha-1) from titicaca and the lower (0.61 t ha-1) from vikinga. the titicaca yield was 26.23% higher than vikinga. similarly higher straw yield (0.89 t ha-1) was obtained from titicaca and the lower (0.76 t ha-1) from vikinga. no significant variations for harvest index was observed between the two cultivars (table 2). effect of sowing date plant height at 15, 30 das and harvest showed significant variation for different sowing dates (table1). at 15 das, the highest plant height (44.57 cm) was obtained from february -10 sowing and the lowest (22.62 cm) from november -10 sowing. at 30 das, the highest plant height (55.63 cm) was obtained from january -10 sowing and the lowest (38.10 cm) from march -10 sowing. at harvest, the maximum plant height (62.54 cm) was obtained from november -10 sowing that similar to all other sowings except march -10 sowing that showed the lowest plant height (42.75 cm). these results were supported with the findings of troiani et al. (2004) who conducted a research on quinoa time sowing and reported second half of the november to the end of december showed the highest plant height. number of branches plant-1 at 15, 30 das and harvest showed significant variation for different sowing dates (table1). at 15 and 30 das, the highest number of branches plant-1 (23.60 and 25.83) was obtained from january -10 sowing and the lowest number of branches (5.50 and 10.13) obtained from november -10 sowing, respectively. at harvest, the highest branch number (23.45) was obtained from january -10 sowing that similar to december – 10 and november – 10 sowing and the lowest branch number (6.51) from march-10 sowing. the highest inflorescence length plant-1 (29.62 cm) was obtained from november 10 sowing that similar to december – 10 sowing (28.33 cm) and the lowest inflorescence length (13.85 cm) obtained from march -10 sowing. weight of 1000-seed of quinoa showed significant variation for different sowing dates (table 2) where the highest 1000-seed weight (2.56 g) was obtained from november -10 sowing that similar to december – 10 sowing (2.47 g) and the lowest 1000-seed weight (1.17 g) from march -10 sowing. november sowing produced seed with 118% higher size compared to that of march sowing. seed size is an important parameter for quinoa seed germination capacity as koyro and eisa (2007) reported that smaller seed size of quinoa showed lower germination capacity. table 1. effect of cultivar and sowing date on plant height and branch number plant-1of quinoa treatments plant height (cm) at branches plant-1 (no.) at 15 das 30 das harvest 15 das 30 das harvest effect of cultivar titicaca 37.49 57.55 a 63.75 a 12.21 15.05 b 16.59 b vikinga 29.36 44.37 b 50.63 b 13.22 16.11 a 17.71 a lsd(0.05) ns 12.936 12.728 ns 1.026 1.073 cv (%) effect of sowing date 17.30 17.41 14.16 13.42 18.32 19.23 november – 10 22.62 b 54.57 a 62.54 a 5.50 d 10.13 c 22.84 a december – 10 29.52 b 54.49 a 62.47 a 9.20 c 13.32 bc 22.80 a january – 10 44.23 a 55.63 a 60.46 a 23.60 a 25.83 a 23.45 a february – 10 44.57 a 52.01 a 57.73 a 14.65 b 16.79 b 10.15 b march – 10 26.17 b 38.10 b 42.75 b 10.64 c 11.82 c 6.51 c lsd(0.05) cv (%) 10.000 24.69 8.749 14.03 8.282 11.83 2.402 15.44 3.524 18.49 2.704 12.88 figures in a column with common letter(s) do not differ significantly at 5% probability level. 70 biswas and tanni seed yield of quinoa showed significant variation for different sowing dates and the highest yield (1.09 t ha-1) was obtained from november -10 sowing that followed by december -10 sowing (0.88 t ha-1) and the lowest seed yield (0.26 t ha-1) from march -10 sowing. the seed yield of quinoa was reduced by 19.27, 32.11, 55.96 and 76.15% for december, january, february and march sowing, respectively compared to that of november sowing. higher seed yield of quinoa at 15 october sowing was also reported by ramesh et al. (2017). the highest straw yield (1.25 t ha-1) was obtained from november -10 sowing that similar to december (0.99 t ha-1) and january (0.90 t ha-1) sowing and the lowest straw yield (0.38 t ha-1) from march -10 sowing. the highest harvest index (47.06%) was obtained from december-10 sowing that similar to november (46.58%) and january (45.12%) sowing and the lowest (40.63%) from march -10 sowing (table 2). table 2. effect of cultivar and sowing date on yield and other parameters of quinoa treatments inflorescence length (cm) wt. of 1000 seeds (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) effect of cultivar titicaca 22.01 2.05 0.77 a 0.89 a 46.39 vikinga 25.18 2.03 0.61 b 0.76 b 44.53 lsd(0.05) cv (%) ns 9.23 ns 12.89 0.089 8.52 0.104 4.28 ns 6.76 effect of sowing date november – 10 29.62 a 2.56 a 1.09 a 1.25 a 46.58 a december – 10 28.33 ab 2.47 a 0.88 bc 0.99 ab 47.06 a january – 10 25.27 b 2.25 b 0.74 c 0.90 b 45.12 ab february – 10 20.86 c 1.75 c 0.48 d 0.62 bc 43.64 b march – 10 13.86 d 1.17 d 0.26 e 0.38 c 40.63 c lsd(0.05) cv (%) 3.094 10.71 0.145 5.81 0.187 10.26 0.372 4.20 2.268 7.86 figures in a column with common letter(s) do not differ significantly at 5% probability level. interaction effect of cultivar and sowing date interaction between cultivar and sowing date showed significant differences on plant height at 15 and 30 das and at harvest (table 3). at 15 das, the highest plant height (50.78 cm) was observed in c1s4 (titicaca with february -10 sowing) which was at par with c1s3, c2s3 and c2s4. the lowest plant height (20.89 cm) was observed in c2s1 (vikinga with november -10 sowing) which was statistically similar with c2s2, c2s5, c1s1 and c1s5. at 30 das, the highest plant height (65.36 cm) was observed in c1s1 (titicaca with november -10 sowing) that statistically similar with c1s2, c1s4, c1s3 and c2s3. the lowest plant height (33.99 cm) was observed in c2s5 (vikinga with march -10 sowing) that similar with c1s5, c2s2 and c2s1. at harvest, the highest plant height (72.83 cm) was found in c1s1 (titicaca with november -10 sowing) which was statistically similar with c1s2, c1s4 and c1s3. the lowest plant height (37.09 cm) was observed in c2s5 (vikinga with march -10 sowing) that similar to c1s5. at 15 das, the highest branch number plant-1 (23.93) was observed in c1s3 (titicaca with january -10 sowing) that similar to c2s3. the lowest branch number plant-1 (5.60) was observed in c2s1 (vikinga with november -10 sowing) that similar to c1s1. quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh 71 table 3. interaction effect of cultivar and sowing date on plant height and branch number plant-1 of quinoa interactions plant height (cm) at branches plant-1 (no.) at 15 das 30 das harvest 15 das 30 das harvest c1s1 24.34 def 65.36 a 72.83 a 5.40 e 10.13 c 25.20 a c1s2 35.61 b-e 65.23 a 71.57 a 9.33 c 13.08 c 21.21 bc c1s3 48.50 ab 57.40 ab 62.80 ab 23.93 a 25.88 a 22.20 abc c1s4 50.78 a 57.55 ab 63.15 ab 12.66 c 14.67 bc 8.46 de c1s5 28.20 c-f 42.20 cd 48.40 cd 9.73 cd 11.50 c 5.86 e c2s1 20.89 f 43.78 cd 52.10 bc 5.60 e 10.13 c 20.40 c c2s2 23.42 ef 43.74 cd 53.50 bc 9.06 d 13.56 c 24.47 ab c2s3 39.96 abc 53.85 abc 58.12 bc 23.26 a 25.78 a 24.70 ab c2s4 38.36 a-d 46.46 bc 52.31 bc 16.63 b 18.90 b 11.83 d c2s5 24.13 def 33.99 d 37.09 d 11.54 cd 12.14 c 7.15 e lsd(0.05) cv (%) 14.284 24.69 12.373 14.03 11.713 11.83 3.397 15.44 4.985 18.49 3.824 12.88 figures in a column with common letter(s) do not differ significantly at 5% probability level. c1 = titicaca, c2 = vikinga, s1 = november -10, s2 = december -10, s3 = january -10, s4 = february 10 and s5 = march -10 sowing at 30 das, the highest number of branches plant-1 (25.88) was observed in c1s3 (titicaca with january -10 sowing) that also similar toc2s3 (vikinga with january -10 sowing). the lowest number of branches plant-1 (10.13) was observed in c1s1 (titicaca with november -10 sowing) that identical to c2s1 (vikinga with november -10 sowing) and similar with c1s5, c2s5, c1s2, c2s2 and c1s4. at harvest, the highest branch number plant-1 (25.20) was found in c1s1 (titicaca with november -10 sowing) that similar to c2s3, c2s2 and c1s3. the lowest number of branches plant-1 (5.86) was observed in c1s5 (titicaca with march -10 sowing) that similar to c2s5. interaction between cultivar and sowing dates showed significant differences on inflorescence length plant-1 at harvest (table 4). the tallest inflorescence (31.46 cm) was found in c2s2 (vikinga with december -10 sowing) which was statistically similar with c2s1, c1s1 and c2s3. the shortest inflorescence (13.37 cm) was observed in c1s5 (titicaca with march -10 sowing) that similar to c2s5. the highest 1000-seed weight (2.58 g) was found in c1s1 (titicaca with november -10 sowing) which was similar to c2s1, c2s2 and c1s2. the lowest 1000-seed weight (1.10 g) was observed in c2s5 (vikinga with march -10 sowing) that similar to c1s5 (titicaca with march -10 sowing). the highest seed yield (1.16 t ha-1) was found in c1s1 (titicaca with november -10 sowing) that similar to c2s1 (1.01 t ha-1) and c1s2 (0.96 t ha-1) and the lowest seed yield (0.21 t ha-1) in c2s5 (vikinga with march -10 sowing) that similar to c1s5 and c2s4. the highest straw yield (1.33 t ha-1) was found in c1s1 (titicaca with november -10 sowing) which was statistically similar to c2s1 and c1s2 and the lowest straw yield (0.33 t ha-1) was observed in c2s5 (vikinga with march -10 sowing) that similar toc1s5, c2s4 and c1s4. the highest harvest index (47.02%) was found in c2s2 (vikinga with december -10 sowing) that similar to all interactions except c2s5 and c2s4 those were statistically similar. 72 biswas and tanni table 4. interaction effect of cultivar and sowing date on yield and other parameters of quinoa interactions inflorescence length (cm) wt. of 1000 seeds (g) grain yield (t ha-1) straw yield (t ha-1) harvest index (%) c1s1 28.50 b 2.58 a 1.16 a 1.33 a 46.59 a c1s2 25.20 b-d 2.47 ab 0.96 ab 1.09 abc 46.83 a c1s3 23.13 c-e 2.20 c 0.86 bc 0.97 bc 46.99 a c1s4 19.77 e 1.75 d 0.54 def 0.63 de 46.15 a c1s5 13.37 f 1.24 e 0.31 fg 0.43 e 41.89 ab c2s1 30.73 a 2.53 a 1.01 ab 1.16 ab 46.54 a c2s2 31.46 a 2.46 ab 0.79 bcd 0.89 bcd 47.02 a c2s3 27.40 a-c 2.30 b 0.62 cde 0.83 cd 42.76 ab c2s4 21.96 de 1.74 d 0.41 efg 0.61 de 40.20 b c2s5 14.34 f 1.10 e 0.21 g 0.33 e 38.89 b lsd(0.05) 4.374 0.205 0.249 0.326 5.875 cv (%) 10.71 5.81 10.26 4.20 7.86 c1 = titicaca, c2 = vikinga, s1 = november -10, s2 = december -10, s3 = january -10, s4 = february -10 and s5 = march -10 sowing conclusion quinoa can be successfully cultivate in bangladesh during rabi season. the cultivar titicaca performed better compared to that of vikinga. among the five sowing dates, sowing at november-10 gave the highest grain yield where cultivar titicaca sown in november could be the best combination. acknowledgements the author acknowledged the financial authority of sher-e-bangla agricultural university, dhaka 1207 for support to startup the research on a new crop quinoa under the umbrella of saures (sher-e-bangla agricultural university research system) research grant. the support from dr. md. sekender ali, pro vice-chancellor of sher-e-bangla agricultural university also gratefully acknowledged for providing seeds of two quinoa cultivars collected from dae. references bazile, d., c. pulvento, a. verniau, m.s. al-nusairi, d. ba, j. breidy, l. hassan, m.i. mohammed, o. mambetov, m. otambekova, n.a. sepahvand, a. shams, d. souici, k. miri and s. padulosi. 2016. worldwide evaluations of quinoa: preliminary results from post international year of quinoa, fao projects in 9 countries, front plant sci. 7: 850. bazile, d., h.d. bertero and c. nieto. 2015. state of the art report on quinoa around the world in 2013; roma: fao & cirad: 589. bazile, d. 2014. state of the art report on quinoa around the world in 2013. in: bazile, d. (ed) food and agriculture organizations of the united nations (fao), santiago. bhargava, a., s. shukla and d. ohri. 2006. chenopodium quinoa-an indian perspective. ind. crop. prod. 23: 73–87. faostat. 2020. quinoa production in 2018. un food and agriculture organization, corporate statistical database. quinoa (chenopodium quinoa willd.) – a potential new crop in bangladesh 73 fernando, s.v., s.v. edmar, g.b. marcel and s. lucas. 2012. development and productivity of quinoa sown on different dates during off-season. revista ciencia agron. 43(3): 510-515. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research (2nded.). int. rice res. inst., a willey int. sci. pub. pp.28-192. jahan, k. and m. hossain. 1998. nature and extent of malnutrition in bangladesh: bangladesh national nutrition survey 1995-96. dhaka: institute of nutrition and food sciences, university of dhaka; p.33. koyro, h.w. and s. eisa. 2007. effect of salinity on composition viability and germination of seeds of chenopodium quinoa willd. plant soil. 302(1): 79-90. louafi, s., d. bazile and j.l. noyer. 2013. conserving and cultivating agricultural genetic diversity: going beyond established cleavages. in: cultivating biodiversity to transform agriculture. versailles: ed. quae, pp.185-222. pulvento, c., m. riccardi, a. lavini, r. d’andria, g. jafelice and e. marconi. 2010. field trial evaluation of two chenopodium quinoa genotypes grown under rainfed conditions in a typical mediterranean environment in south italy. j. agron. crop sci. 196: 407-411. ramesh, k., k.b. suneetha devi, k.a. gopinath and m. uma devi. 2017. growth, yield and economics of quinoa as influenced by different dates of sowing and varied crop geometry. int. j. pure appl. biosci. 5(6): 849-854. risi, j.c. and w.g. nicholas. 1991. effects of sowing date and sowing rate on plant development and grain yield of quinoa (chenopodium quinoa) in a temperate environment. the j. agril. sci. 117(03): 325-332. sajjad, a., h. munir, ehsanullah, s.a. anjum, m. tanveer and a. rehman. 2014. growth and development of quinoa (chenopodium quinoa willd.) at different sowing dates. agri. res. 52(4): 535-546. troiani, r.m., t.m. sanchez, n.b. reinaudi and l.a. de ferramola. 2004. optimal sowing dates of three species of grain –bearing amaranth in the semi-arid argentine pampa. spanish agri. res. 2(3): 385-391. world bank. 2005. maintaining momentum to 2015: an impact evaluation of interventions to improve maternal and child health and nutrition in bangladesh. washington, the world bank. bangladesh agron. j. 2021, 24(1): 43-55 physiological and yield responses of some selected rapeseed/mustard genotypes to salinity stress f. ahmed1, i.m. ahmed1, a.f.m. shamim ahsan1, b. ahmed1 and f. begum2 1plant physiology division, bari, gazipur-1701 2oil seed research center, bari, gazipur-1701 corresponding e-mail: faruquebari@gmail.com (received: 12 february 2021, accepted: 19 february 2021) keywords: salnity, rapeseed/mustard, toerant genotypes, physiological parameters, seed yield abstract an experiment on rapeseed/mustard genotypes was conducted during 2019-2020 rabi season in vinyl house of plant physiology division of bangladesh agricultural research institute (bari), gazipur to find out the salt-tolerant genotypes based on the responses of their physiological parameters and yield. five selected rapeseed/ mustard genotypes (v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari sarisha-14, v5 = bd-6950) were tested at three salinity levels (s0= 0, s1= 5 and s2=10 ds m-1). irrespective of the genotypes, salinity stress showed a negative effect on the measured physiological parameters as well as seed yield. leaf chlorophyll contents, leaf area, leaf photosynthetic rate and total dry matter (tdm) were reduced due to salinity stress which ultimately affected seed yield irrespective of the genotypes. however, these parameters were less affected by the salinity in v1 and v2 genotypes compared to others. sodium and potassium ion contents and their ratios (k+/na+) in leaf tissues were significantly affected by salinity stress. among the genotypes, v1 and v2 showed higher k+/na+ ratios in leaf under both the salinity treatments, and that phenomenon indicated their higher tolerance to salinity than the other genotypes. catalase (cat), peroxidase (pod) activity and malondialdehyde (mda) content of the genotypes increased due to salinity stress with variability among the genotypes. the higher cat and pod activity with lower mda content was found in v1 and v2 genotypes which indicated their better salt tolerance ability compared to others. these genotypes also showed higher seed yield under both the salinity levels (5 and 10 ds m-1) compared to other genotypes. based on the responses of physiological parameters and seed yield to salinity, the genotypes jun-536(v1) and bjdh-12(v2) could be considered relatively tolerant to salinity stress. introduction salinity is an important limiting factor that causes low crop yield with inferior quality. the adverse effects of salinization cause both osmotic stress and ionic toxicity in plants, leading to secondary stresses such as nutritional disorders and oxidative stress. one of the most detrimental effects of salinity stress is the accumulation of na+ and cl− ions in tissues of plants exposed to soils with high nacl concentrations. entry of both na+ and cl−into the cells causes’ severe ion imbalance and the excess uptake of them might cause significant physiological disorder(s). generation of reactive oxygen species (ros) like singlet oxygen, superoxide radical, hydrogen peroxide, and hydroxyl radicals exposed to salinity stress causes injury to plants. the genotypes which produce more ros scavenging enzymes under stress can be considered as comparatively tolerant genotype. mailto:faruquebari@gmail.com 44 ahmed et al. among the oilseed crops grown in bangladesh, rapeseed/mustard (brassica spp.) holds the first position acarage and production. it constitutes an important source of edible oil and is grown under diverse agro-ecological situations. this crop can also be grown successfully in the coastal districts of southern bangladesh where the cropping intensity is lower than in other parts of the country. however, most of the southern districts of the country are under saline zones which cover an area of 25-30% of the total cultivable land (srdi, 2012). though soil salinity is the most dominant factors limiting crop production in the coastal areas of bangladesh during dry season, salt-tolerant rapeseed/mustard can bring substantial changes in the agricultural practices in those saline soils. genetic variations in salt tolerance exist in the glycophytes, and the degree of salt tolerance varies with plant species and varieties within a species. there also exist differences in sensitivity to salinity among brassica cultivars which need to be found out in a systematic study. therefore, the present study was conducted to find the tolerant mustardrapeseed genotype(s) based ontolerance of physiological and yield parameters. materials and methods a pot experiment on mustard-rapeseed was conducted in the vinyl house of plant physiology division, bari, gazipur during the rabi season of 2019-2020. five selected mustard/rapeseed genotypes, namely: v1= jun-536, v2= bjdh-12, v3= bd-10115, v4= barisarisha-14, v5= bd-6950 was grown in three salinity levels (s0 = 0, s1 = 5 and s2 =10 ds m-1) in pots inside a plastichouse of plant physiology division, bari, gazipur during rabi season of 2019-2020. salinity was imposed at 20 days after sowing by adding nacl solution. salt solution was prepared by dissolving calculated amount of lab grade nacl with pond water. salt solution was applied with an increment of 5ds m-1 every alternate day until desired salinity levels were attained. in the control treatment, pond water was used which salinity level was 0.2 ds m-1. salinity levels were maintained by monitoring and adding salt solution when required up to maturity. the experiment was laid out in a factorial randomized complete block design with 5 replications. plastic pots (top dia: 25 cm, bottom dia: 18 cm and height 25 cm; 12 kg soil) were filled up with soil and cowdung (4:1). seeds were sown in each pot on 12 november 2019. fertilizers were applied @100-30-80-20-3-1 kgha-1npksznb. half of n and all other fertilizers were applied as basal and the remaining n was applied at 20 days after sowing (das). irrigation was done as and when required for maintaining adequate soil moisture. after emergence plants were thinned to three plants in each pot. plants from three pots were sampled for leaf area and dry matter measurement at different growth stages. sampled plants were separated into leaf, stem, and siliqua depending on growth stages. leaf area was measured by an automatic area meter (li-3100 c; li-cor, usa). plant parts were dried in an oven for 72 hours at 70oc and dry weight was recorded. at harvest yield and yield components data were collected from three pots and analyzed statistically and mean separation was done by lsd test at 5% level of significance using data processing software. chlorophyll estimation leaves of each genotype were properly cut into small pieces and weighed 0.5 g and were taken for chlorophyll estimation at 55 das. chlorophyll a, chlorophyll b and total chlorophyll were estimated following arnon’s method (arnon, 1949). the absorbance of the solution was read at 645 and 663 nm for chlorophyll a, chlorophyll b and total chlorophyll. calculation: chlorophyll a (mg g-1) = {12.7 (d663) 2.69 (d645)}v/(1000w) chlorophyll b (mg g-1) = {22.9 (d645) 4.68 (d663)}v/(1000w) response of rapeseed/mustard genotypes to salinity stress 45 total chlorophyll (mg g-1) = 20.2 (d645) + 8.02 (d663)v/(1000w) where, d = optical density; v = final volume of 80% acetone (ml); w = fresh weight of sample taken (g) leaf photosynthesis measurement: leaf photosynthetic rate was measured on 50 das by a portable photosynthesis system (li-6800, usa). fully expanded third leaf from the top was used for this purpose and the measurement was carried out from 10 am to 11.30 pm. sodium and potassium ion uptake measurement: at 55 das, fully expanded third leaf from the top was collected from each treatment for determining of sodium and potassium ion content in leaf tissue. cell sap of leaf was extracted from the leaf using mortar and pistil. laquatwin sodium ion meter (na-11, horiba, japan) and laquatwin potassium ion meter (k-11, horiba, japan) were used for na+ and k+ determination, respectively. enzyme extraction and assays using a pre-cooled mortar and pestle, 0.5 g of leaf tissue was homogenized in 1 ml of 50 mmice-cold k-phosphate buffer (ph 7.0) containing 100 mmkcl, 1 mmascorbate, 5 mmβmercaptoethanol, and 10% (w/v) glycerol. the homogenates were centrifuged at 11,500×g for 10 min, and the supernatants were used for determining of enzyme activity. all procedures were performed at 0°c to 4°c. determination of protein the protein concentration of each sample was determined following the method of bradford (1976) using bsa as a protein standard where 5, 10, 15, 20, 25 μgμl-1 protein concentrations were used to prepare the standard curve. peroxidase (pod, ec 1.11.1.7): pod activity was estimated according to hemeda and klein (1990). the reaction mixture contained 25 mm k-p buffer (ph 7.0), 0.05% guaiacol, 10 mm h2o2 and enzyme. the activity was determined by the increase in absorbance at 470 nm due to guaiacol oxidation for 1 min using extinction coefficient of 26.6 mm-1 cm-1. catalase (cat, ec: 1.11.1.6): cat activity was measured according to the method of hossain et al. (2010) by monitoring the decrease of absorbance at 240 nm for 1 min caused by the decomposition of h2o2. the reaction mixture contained 50 mm k-phosphate buffer (ph 7.0), 15 mm h2o2, and enzyme solution in a final volume of 0.7 ml. the reaction was initiated with enzyme extract, and the activity was calculated using the extinction coefficient of 39.4 m−1 cm−1. lipid peroxidation the level of lipid peroxidation in plant tissues was expressed as 2-thiobarbituric acid (tba) reactive metabolites, mainly malondialdehyde (mda), and was determined according to hodges et al. (1999). fresh samples (leaves) of around 0.5 g were homogenized in 4.0 ml of 1% trichloroacetic acid (tca) solution and centrifuged at 10,000g for 10 min. the supernatant was added to 1ml 0.5% (w/v) tba made in 20% tca. the mixture was heated in boiling water for 30 min, and the reaction was stopped by placing the tubes in an ice bath. the samples were centrifuged at 10,000×g for 10 min, and the absorbance of the supernatant was recorded at 532 nm. correction of non-specific turbidity was made by subtracting the absorbance value read at 600 nm. the level of lipid peroxidation was expressed as nmol g−1 fresh weight, with a molar extinction coefficient of 0.155 mmcm−1. 46 ahmed et al. results and discussion leaf chlorophyll content interaction effect of genotypes and salinity showed significant influence on chlorophyll a content (fig. 1). under control conditions (non saline) chlorophyll-a content of the genotypes were identical while chlorophyll-b differed significantly. fig.1. interaction effect of genotype and salinity on leaf chlorophyll content of mustard/rapeseed at 55 das (vertical bars indicate se). v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = barisarisha-14, v5 = bd-6950 (s0= 0, s1= 5 and s2=10 ds m-1salinity). the maximum chlorophyll-b content was found in v2 which was identical with v3 but significantly higher than others. the lowest chl b was detected in v4 which was identical to that of v5. total chlorophyll content was the highest in v2 which was identical with v3 but significantly higher than others and the lowest value was found in v4. at 5ds m-1 salinity, all the genotypes showed statistically similar chlorophyll-content except v4 which showed the lowest value. chlorophyll-b content of v1 and v2 were identical and these values were significantly higher than v3, v4 and v5 genotypes which showed statistically similar values. the total chlorophyll content of v1 and v2 were identical but significantly higher than others. at 10ds m-1 salinity, chlorophyll-a content of v1, v2 and v3 was identical which were significantly higher than the other two genotypes. again chlorophyll-a content of v4 and v5 were statistically similar. the lowest value was found in v4. chlorophyll-b content was the highest in v2 which was identical with v1 and v5 but significantly higher than others. the lowest value was found in v4. the total chlorophyll content was the highest in v2 which was identical with v1 but significantly higher than others. total chlorophyll content of v3 and v5 genotypes were identical and the lowest value was found in v4. in general, the photosynthetic pigments i.e. chlorophyll content decreased with the increase of salinity. shah (2007) also reported reduced chlorophyll content in mustard under salinity stress. photosynthesis interaction effect of genotype and salinity showed significant influence on leaf photosynthetic rate (fig. 2). under control conditions, the highest photosynthetic rate was found in v5 (23.55 0 0.2 0.4 0.6 0.8 1 1.2 1.4 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 c h lo ro p h y ll ( m g g -1 f w ) treatments chl a c hl b response of rapeseed/mustard genotypes to salinity stress 47 µmol m-2s-1) which were identical with all other genotypes except v4 which showed the lowest value. at 5ds m-1 salinity, the highest photosynthetic rate was observed in v5 which was identical with v3 and v2. again, v2 and v1 were identical and the lowest value was found in v4 genotype. at 10 ds m-1 salinity, the highest rate was recorded in v2 (15.05 µmolm-2s-1) which were identical with other genotypes, except v4, which showed the lowest value (12.67 µmol m-2 s-1). in general, with the increase of salinity levels photosynthetic rate was reduced irrespective of the genotypes. salt-induced reduction in photosynthesis is associated with the partial stomatal closure and/or the non-stomatal limitation which is involved in the dark enzymatic processes of co2 assimilation e.g. the decrease in rubisco activity and content, or pi-regeneration capacity (ashraf and harris, 2013). fig. 2. interaction effect of genotype and salinity on leaf photosynthesis of mustard/ rapeseed at 55 das (vertical bars indicate se) v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari-14, v5 = bd-6950s0= 0, s1= 5 and s2=10 dsm-1 salinity. leaf area and dry matter production leaf areaplant-1 of the mustard-rapessdgenotypes differed significantly under different levels of salinity stress (table 1). under control conditions at 45 das, the maximum leaf area was observed in v2 (410 cm2), which was identical with v1 and v3. at 5 ds m-1salinity, the highest leaf area was found in v2 (396.67 cm2), which was identical with v1, v3 and v5 genotypes. the lowest value was found in v4 (217.67 cm2) genotype. under 10 ds m-1, v2 produced the highest leaf area (248.33 cm2), which was identical with all other genotypes and the lowest value was observed in v4 (167.67 cm2). in general leaf area was reduced with increased salinity levels irrespective of the genotypes. salinity-induced osmotic stress is considered responsible for the reduced leaf area in canola and wild mustard (huang and redmann, 1995). furthermore, high salinity is known to induce ionic stress, which causes premature abscission and senescence of adult leaves, thus reducing the available photosynthetic area (munns, 2002). at 55 das, under control condition (no salinity), the maximum leaf area was found in v2 (438.33 cm2), which was identical with all other genotypes, except v4 which produced the lowest leaf area. at 5 ds m-1salinity, v2 (401.67 cm2) produced the highest leaf area which was identical with all other genotypes except v4 which produced the lowest leaf area (246.67 cm2). 0 5 10 15 20 25 30 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 p h o to sy n th e si s (µ m o l m -2 s -1 ) treatments 48 ahmed et al. at 10 ds m-1 salinity, the highest leaf area was found in v2 and was identical with all other genotypes except v4 which produced the lowest leaf area (197 cm2). total dry matter production of the genotypes was identical at 45 das under control conditions, although comparatively higher values were observed in v2 (8.0 g plant-1) and v1 (7.83 gplant-1) and the lowest (6.93 g plant-1) in v4. at 5 dsm-1 salinity, the highest tdm was found in v2 (6.98 gplant-1) which were identical with all other genotypes except v4 which produced the lowest dry matter. at 10 dsm-1 salinity, all the genotypes showed identical values except v4 which showed the lowest tdm (4.07 g plant-1). at 55 das under control condition, tdm production of v1, v2, v3 and v5 was identical and the lowest value was found in v4. at 5ds m-1salinity, statistically similar tdm was observed in all the genotypes except v4 which was lowest among the genotypes. at 10 ds m-1salinity, the maximum tdm was observed in v1 which was identical with v2, similarly v2 and v3 were identical and the lowest value was found in v4. at harvest under control condition, tdm production of the genotypes was identical except v4 which produced the lowest. at 5ds m-1 salinity tdm of the genotypes were statistically identical. under 10 ds m-1 salinity, the maximum tdm was found in v1 which was identical with v2, v3 and v5 but lowest in v4. dry matter production which is considered as an index of photosynthetic activity (essa and al-ani, 2001) was reduced under saline conditions. reduction in total dry matter accumulation under saline conditions was also reported by shamsul et al. (2011) in indian mustard (brassica juncea). table 1. interaction effect of genotype and salinity on leaf area and tdm of mustard/ rapeseedgenotypes salinity genotype leaf area (cm2) total dry matter (g plant -1) 45 das 55 das 45 das 55 das harvest s0 v1 396.67 437.33 7.83 9.24 10.80 v2 410.00 438.33 8.00 9.17 10.20 v3 389.67 401.77 7.50 9.00 10.47 v4 326.00 342.67 6.93 7.27 9.90 v5 380.33 410.67 7.10 9.00 10.20 s1 v1 380.00 398.67 6.83 8.88 9.33 v2 396.77 401.67 6.98 8.98 9.53 v3 378.33 388.33 6.22 8.10 9.10 v4 217.67 246.67 5.49 6.83 8.20 v5 365.00 391.67 6.20 8.77 9.17 s2 v1 244.33 303.67 5.85 7.80 8.87 v2 248.33 310.00 5.98 7.65 8.63 v3 240.00 302.00 5.63 7.67 8.25 v4 167.67 197.00 4.07 5.99 7.98 v5 243.33 298.67 5.87 7.77 8.60 lsd (0.05) 27.68 38.51 1.42 1.27 1.50 cv (%) 5.2 6.6 11.2 9.4 9.6 s0=0, s1=5 and s2=10 ds m-1 salinity. v1= jun536, v2 = bjdh-12, v3 = bd-10115, v4 = bari-14, v5 = bd-6950. potassium and sodium ion in leaf tissue the interaction effect of genotype and salinity on potassium content in leaf tissue was significant (table 2). under control conditions, the maximum k+ was observed in v3 (2700 ppm) which response of rapeseed/mustard genotypes to salinity stress 49 was identical with v1 and v2 but significantly higher than others. at 5ds m-1, the highest k+ was recorded in v4 (2900 ppm) and the lowest value was found in the v5 (2300 ppm) genotype. at 10ds m-1 salinity, the highest k+ was recorded in v1 (4800 ppm) genotype and the lowest value was found in v4 which was identical with v2. the adverse effect of salinity on plant growth may be due to ion cytotoxicity and osmotic stress. high levels of k+in young expanding tissue are associated with salt tolerance in many plant species (bandeh-hagh et al., 2008; shabala, 2009). sodium content in leaf tissue was significantly lower in the control treatment than other salinity levels irrespective of the genotypes, and the maximum na+ content under no salinity condition was found in v4 which was identical with v5 but significantly higher than others. sodium content in leaf tissues increased significantly due to salinity stress irrespective of the genotypes. at 5ds m-1 salinity, the highest na+ content was found in v4 (650 ppm) and the lowest value was observed in v3 (170 ppm) which was identical with v2. at 10ds m-1 salinity, the highest na+ content was found in v4 (1400 ppm) which was significantly higher than all other genotypes. the lowest na+ content was found in v2 (260 ppm). the potassium and sodium ion ratio in leaf tissue was drastically reduced due to salinity stress. genotypes showed significant variability in k+/na+ ratios in leaf tissue under control conditions. the highest value was found in v2 (44.14) which was significantly higher than others. genotypes v2 and v5 showed moderate ratios of k+/na+ content in leaf tissue and the lowest in v4 (14.34). at 5ds m-1 salinity, the maximum value was observed in v2 (13.73) which was identical with all other genotypes and the lowest value was found in v4 (4.50). at 10 ds m-1 salinity, the maximum value was observed in v2 (12.70) which was identical with v1 (10.97) and v3 (10.92) but significantly higher than other genotypes. the lowest value of k+/na+ ratio was found in v4 (2.23 ppm) and v5 showed the moderate value. a decrease in uptake of potassium (k) and consequent decrease in growth at higher sodium (na) concentration has been reported earlier by ashraf and mcneilly (2004). table 2. interaction effect of genotype and salinity on potassium and sodium ion uptake and their ratios in mustard/rapeseed genotypes at 55 das salinity genotype k+ (ppm) na+(ppm) k+/na+ s0 v1 2500 68 36.87 v2 2600 59 44.14 v3 2700 120 22.78 v4 2400 170 14.34 v5 2200 110 20.03 s1 v1 2500 210 11.91 v2 2600 190 13.73 v3 2300 170 13.55 v4 2900 650 4.50 v5 2500 220 11.52 s2 v1 4800 440 10.97 v2 3300 260 12.70 v3 4000 370 10.92 v4 3100 1400 2.23 v5 4400 580 7.61 lsd (0.05) 225.86 72.25 2.78 cv (%) 4.5 11.9 10.5 s0=0, s1=5 and s2=10 ds m-1 salinity. v1= jun536, v2 = bjdh-12, v3 = bd-10115, v4 = bari-14, v5 = bd-6950. 50 ahmed et al. antioxidant activity antioxidant activity was significantly affected due to salinity stress (fig. 3). under control treatment, higher catalaze (cat) activities were found in v5 and lower in v2. at 5ds m-1 salinity, the highest cat activity was observed in v2 which was significantly higher than others. fig. 3. effect of salinity stress on the catalyze activity in rapeseed/mustard genotypes at 55das. (vartical bar indicate se). v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari14, v5 = bd-6950.s0= 0, s1= 5 and s2=10 ds m-1salinity. at 10 ds m-1salinity cat activity was higher than control and 5ds m-1salinity and the maximum activity was observed in v2 which was identical with v1 but significantly higher than others. cat activity of v3 and v5 were identical and the lowest was found in v4. peroxidase (pod) activity also increased due to temperature stress compared to control (fig.4). under control conditions, comparatively higher pod activity was found in v5 followed by v2 and v1 and the lower in v4 and v3. at 5ds m-1salinity the highest pod activity was observed in v2 which was significantly higher than other. at 10 ds m-1salinity pod activity of v1, v2 and v5 were satirically identical, v3 showed moderate activity while the lowest was found in v4. the reduced rate of photosynthesis increases the formation of reactive oxygen species (ros) and increases the activity of enzymes (cat and pod) that detoxify the ros (foyer and noctor, 2005). fig. 4. effect of salinity stress on the pod activity in rapeseed/mustard genotypes at 55 das (varticalbars indicatese).v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari-14, v5 = bd-6950s0=0, s1= 5 and s2=10 ds m-1salinity. 0 0.1 0.2 0.3 0.4 0.5 0.6 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 c a t ( m m o l g -1 f w m im -1 ) treatments 0 0.5 1 1.5 2 2.5 3 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 p o d ( m m o l g 1 f w m im -1 ) treatments response of rapeseed/mustard genotypes to salinity stress 51 malondialdehyde (mda) content also increased due to salinity stress compared to control (fig. 5). under control conditions, the genotypes showed variability in mda activity which increased with the increase in salinity levels. at 5ds m-1salinity, the maximum mda activity was foun in v4 followed by v5 and v3, and the lowest was found in v2. at 10 ds m-1salinity, almost a similar trend was observed where the highest mda was found in v4 and the lowest in v2. higher mda content in the cell is correlated with salt stress sensitivity while lower mda content displays higher antioxidative ability, reflecting higher tolerance to stress (noreen and ashraf, 2009). fig. 5. effect of salinity stress on the mda activity in rapeseed-mustard genotypes at 55 das (vertical bars indicate±se). v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari14, v5 = bd-6950. s0= 0, s1= 5 and s2=10 ds m-1salinity. yield and yield contributing characters effect of genotypes genotypes showed significant difference in plant height (table 3). the tallest plant was found in v3 (127.33 cm) which was significantly higher than all other genotypes. siliquaplant-1 of the genotypes also varied significantly. the highest number of siliquaplant-1 was recorded in v5 (115.82) and the lowest siliquaplant-1 was recorded in v4 (57.37) genotype. the number of seedssiliqua-1 of the genotypes differed significantly. table 3. effect of genotype on yield and yield component of mustard/rapeseed genotype plant height (cm) no. of siliqua plant-1 no. of seeds siliqua-1 1000-seed weight (g) seed yield plant-1 (g) v1 117.96 94.56 13.44 2.97 3.55 v2 100.59 95.26 13.99 3.19 3.91 v3 127.33 79.74 15.69 3.10 3.59 v4 73.56 57.37 25.84 3.27 2.91 v5 110.37 115.82 13.24 2.80 3.26 lsd (0.05) 7.56 13.45 2.22 0.27 0.31 cv (%) 7.50 10.50 11.40 9.30 9.60 v1= jun536, v2 = bjdh-12, v3 = bd-10115, v4 = bari-14, v5 = bd-6950. 0 10 20 30 40 50 60 70 80 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 m d a ( n m o l g -1 f w m im -1 ) treatments 52 ahmed et al. the highest number of seedssiliqua-1 was observed in v4 (25.84) which were significantly higher than other genotypes and the lowest value was observed in v5 (13.24). the seed size of the genotypes varied significantly. the highest 1000-seed weight was recorded in v4 (3.27 g) which was significantly higher than others and the lowest was recorded in v5 (2.80 g). seed yieldplant-1 of the genotypes varied significantly. the highest seed yield was found in v2 which significantly higher than others. but the lowest yield was observed in v4. effect of salinity salinity stress significantly affected yield and yield contributing characters of rapeseed/mustard genotypes (table 4). plant height was significantly reduced due to salinity stress. the tallest plant was recorded in control (125.44 cm) condition while the shortest in 10 ds m-1salinity treatment (86.29 cm). table 4. effect of salinity on yield and yield components of rapeseed/mustard salinity plant height (cm) no. of siliqua plant-1 no. of seeds siliqua-1 1000-seed weight (g) seed yieldplant-1 (g) s0 125.44 91.64 17.39 3.29 4.16 s1 100.16 85.18 16.50 3.09 3.38 s2 86.29 76.82 15.42 2.82 2.79 lsd(0.05) 5.85 10.42 1.72 0.21 0.24 cv (%) 7.50 10.50 11.40 9.30 9.60 s0= 0, s1= 5 and s2=10 ds m-1 the most common undesirable effect of salinity on the crop of brassica is the reduction in plant height, component characters of yield as well as deterioration of the product quality (zamani et al., 2010). siliquaplant-1 was significantly reduced due to salinity stress, the highest number was observed in the control (91.64) condition which was identical with 5ds m-1salinity level and the lowest (76.82) in 10 dsm-1. a negative effect of salinity on the number of siliqua plant-1 of indian mustard was also observed by kripa et al. (2011). the highest number of seedssiliqua-1 was found in the control conditions (17.39) which was identical with 5 ds m-1and the lowest (15.42) in 10 ds m-1salinity. these results corroborate the findings of ahmad (2010). reduced seed size was observed due to salinity stress. the highest 1000-seed weight was found in the control conditions (3.29 g) which was significantly higher than others and the lowest (2.82 g) in 10 ds m-1salinity. seed yield was also reduced due to salinity stress and the highest seed yield (4.16gplant-1) was recorded in the control conditions and the lowest (2.79 gplant-1) in 10 ds m-1 salinity. this finding is supported by kripa et al. (2011). interaction effect of genotype and salinity on seed yield interaction effect of genotype and salinity showed significant influence on seed yieldplant-1 (fig.6). under control conditions, the seed yield of v1 and v2 were identical. at 5 ds m-1salinity the maximum seed yield was found in v2 which was identical with v1, v3 and v5 but significantly higher than v4. at 10 ds m-1salinity v2 showed the highest seed yield which was significantly higher than other. the lowest yield was found in v4 genotype. salinity may reduce the crop yield by upsetting the water and nutritional balance of plants (francois, 1994; islam et al., 2001). response of rapeseed/mustard genotypes to salinity stress 53 fig. 6. interaction effect of genotype and salinity on the seed yield of rapeseed/mustard (vertical barsindicate se) v1= jun-536, v2 = bjdh-12, v3 = bd-10115, v4 = bari sarisha-14, v5 = bd-6950. s0= 0, s1= 5 and s2=10 ds m-1salinity. conclusion results revealed that genotypes jun-536 and bjdh-12 were comparatively salt-tolerant as evaluated based on seed yield and important physiological parameters. references ahmad, b. 2010. effects of salinity on yield and component characters in canola (brassica napus l.) cultivars. not. sci. biol. 2(1): 81-83. arnon, d.i. 1949. copper enzymes in isolated chloroplasts. polyphenoloxidase in beta vulgaris. plant physiol. 24: 1. ashraf, m. and p.j.c. harris. 2013. photosynthesis under stressful environments: an overview. photosynthetica 51: 163-190. ashraf, m. and t. mcneilly. 2004. salinity tolerance in brassica oilseeds. critical rev. plant sci. 23(2): 157-174. bandeh-hagh, a., m. toorchi, a. mohammadi, n. chaparzadeh, g.h. salekdeh and h.kazemnia. 2008. growth and osmotic adjustment of canola genotypes in response to salinity. j. food agric. environ. 6(2):201-208. bradford, m.m. 1976. a rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. anal. biochem. 72: 248-254. chakraborty, k., r.k. sairam and r.c. bhattacharya. 2012. differential expression of salt overly sensitive pathway genes determines salinity stress tolerance in brassica genotypes. plant physiol. biochem. 51:90-101. essa, a.t. and d.h. al-ani. 2001. effect of salt stress on the performance of six soybean genotypes. pakistan. j. biol. sci. 4: 175-177. foyer, c.h. and g. noctor. 2005. oxidant and antioxidant signalling in plants: a re-evaluationof the concept of oxidative stress in a physiological context. plant cell environ.28:1056-71. 0.00 1.00 2.00 3.00 4.00 5.00 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 v1 v2 v3 v4 v5 s0 s1 s2 y ie ld p la n t -1 (g ) treatments 54 ahmed et al. francois, l.e. 1994. growth, seed yield, and oil content of canola grown under saline environments. agron. j. 86(2):233-237. hemeda, h.m. and b.p. klein. 1990. effects of naturally occurring antioxidants on peroxidase activity of vegetable extracts. j. food sci. 55: 184-185. hodge, d.m., j.m. delong, c.f. forney and r.k. prange. 1999. improving the thiobarbituric acidreactive-substance assay for estimating lipid peroxidation in plant tissues containing anthocyanin and other interfering compounds. planta 207(4): 604-611. hossain, m.a., m. hasanuzzaman and m. fujita. 2010. up-regulation of antioxidant and glyoxalase systems by exogenous glycinebetaine and proline in mungbean confer tolerance to cadmium stress. physiol. mol. biol. plants 16: 259–272. huang, j. and r.e. redmann. 1995. physiological responses of canola and wild mustard to salinity and contrasting calcium supply. j. plant nutr. 18(9): 1931-1949. islam, m.r., m.a.r. bhuiyan, b. prasad and m.a. quddus. 2001. salinity effect on yield andcomponent characters in rapeseed and mustard varieties. j. biol. sci. 1(9):840-842. james, r.a., c. blake, c.s. byrt and r. munns. 2011. major genes for na+ exclusion, nax1 and nax2 (wheat hkt1; 4 and hkt1; 5), decrease na+ accumulation in bread wheat leaves under saline and waterlogged conditions. j. expt. bot. 62(8): 2939–2947. khan, n.a. 2003. nacl inhibited chlorophyll synthesis and associated changes in ethylene evolution and antioxidative enzyme activities in wheat. biol. plant. 47: 437-440. khan, n.a., h.r. ansari, m. khan and r.m. samiullah. 2002. effect of phytohormones on growth and yield of indian mustard. indian j. plant physiol. 7: 75-78. kim, y., j. arihara, t. nakayama, n. nakayama, s. shimada and k. usui. 2004. antioxidative responses and their relation to salt tolerance in echinochloa oryzicola vasing and seteriavirdis (l.) beauv. plant growth regul. 44: 87-92. kripa, s., s.k.s. parihar, k. kuldeep, d. kant and k. arun. 2011. relative salt tolerance of indian mustard (brassica juncea) genotypes in relation to germination, growth and seed yield. j. oilseed brassica. 2(2): 76-82. marschner, h. 1986. mineral nutrition in higher plants. academic press, london, pp.477-542. mehmood, a., a. hussain, m. irshad, m. hamayun, a. iqbal and n. khan. 2019. in vitro production of iaa by endophytic fungus aspergillusawamori and its growth promoting activities in zea mays. symbiosis 77: 225–235. munns, r. 2002. comparative physiology of salt and water stress. plant cell environ. 25: 239-250. noreen, z. and m. ashraf. 2009. assessment of variation in antioxidative defense system in salttreated pea (pisumsativum) cultivars and its putative use as salinity tolerance markers. j. plant physiol. 166(16): 1764–1774. shabala, s. 2009. salinity and programmed cell death: unraveling mechanisms for ion specific signaling. j. expt. bot. 60:709–712. shabala, s. 2013. learning from halophytes: physiological basis and strategies to improve abiotic stress tolerance in crops. ann. bot. 112: 1209–1221. shah, s.h. 2007. effects of salt stress on mustard as affected by gibberellic acid application. gen. appl. plant physiol. 33(1-2): 97-10. shamsul, h., b.a. mir, a.s. wani, s.a. hasan, i. mohd and a. aqil. 2011. screening of salt-tolerant genotypes of brassica juncea based on photosynthetic attributes j. plant interactions. 6(1): 53-60. shrivastava, p. and r. kumar. 2015. soil salinity: a serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation. saudi j. biol. sci. 22:123–131. response of rapeseed/mustard genotypes to salinity stress 55 song, x.s., w.h. hu, w.h. mao, j.o. ogweno, y.h. zhou and j.q. yu. 2005. response of ascorbate peroxidase isoenzymes and ascorbate regeneration system to abiotic stresses in cucumis sativus l. plant physiol. biochem. 43(12): 1082–1088. srdi. 2012. saline soils of bangladesh. soil resources and development institute. ministry of agriculture, farmgate, dhaka-1215. sudhir, p. and s.d.s. murthy. 2004. effects of salt stress on basic processes of photosynthesis. photosynthetica, 42:481486. xia, x.j., c.j. gao, s.l. xong, y.h. zhou, k.a.i. shi and j.q. yu. 2014. role of h2o2 dynamics in brassinosteroid-induced stomatal closure and opening in solanum lycopersicum. plant cell environ. 37: 2036–2050. zamani z., m.t. nezami, d. habibi and m.b. khorshidi. 2010. effect of quantitative and qualitative performance of four canola cultivars (brassica napus l.) to salinity conditions. adv. environ. biol. 4(3): 422-427. bangladesh agron. j. 2021, 24(2): 63-72 enhancement the productivity of processing category potato by biochar t. s. roy1, b. r. das1, n. sultana1, r. chakraborty1 and m. s. rahman2 1department of agronomy, 2department of bio chemistry, 4 department of agricultural chemistry, faculty of agriculture, sher-e-bangla agricultural university, bangladesh corresponding author: tuhinsuvraroy@sau.edu.bd (received: 19 august 2021, accepted: 30 october 2021) keywords: tuber yield, french fry, biomass inoculation, potato abstract the application of biochar may enhance the yield of potato for different processing categories. a field experiment was conducted at sher-e-bangla agricultural university, dhaka-1207, during the period from november, 2020 to april, 2021 to find out the response of biochar on yield of potato for different processing categories. the experiment comprised of potato varieties (3): v1: bari alu-29 (courage), v2: bari alu-28 (lady rosetta) and v3: bari alu-25 (asterix) and biochar level (5): b0: 0 t ha-1, b1: 2.50 t ha-1, b2: 5.00 t ha-1 and b3: 7.50 t ha-1 and b4: 10 t ha-1. the study was laid out in a randomized complete block design with 3 replications. the results showed that biochar amendment could enhance the yield of processing category potato. the total yield and marketable yield of potato gradually increased with increasing biochar level. the results also revealed that the processing category potato viz., canned, chips and french fry potato yield progressively increased with advancing biochar level irrespective of varieties except dehydrated category. in case of marketable yield, bari alu-25 and bari alu-29 with biochar level 5 to 10 t ha-1performed superior than other combinations and produced 19.50 to 21.30 t ha-1which are 18.54 to 36.45% higher than without biochar. the combination of v2b4 produced maximum canned (8.10 t ha-1) and dehydrated potato (10.09t ha-1) but v3b4 made significantly highest chips (9.03 t ha-1) and french fry (5.70 t ha-1) potato, whereas, bari alu-29 and bari alu-28 did not produce any french fry category potato. however, the level of biochar of 5 to 10 t ha-1 could enhance processing category potato production. it may be concluded that potato growers may apply biochar along with recommended rate of other fertilizers for producing maximum processing category potato. introduction among the world top ten potato producing countries, bangladesh ranked the 8 th position (faostat, 2019). beside of area and production of potato in bangladesh, the yield has also been increasing but, the quality of potato are very low in compared to those of the other leading potato growing countries like belgium, france, usa, denmark, the netherlands, uk (faostat, 2019). the addition of soil amendment is necessary to restore the fertility of the soil. biochar is one of the soil amendments that can improve soil fertility (ding et al., 2016; hunt et al., 2010). biochar is produced by pyrolysis of biomass under low or anaerobic conditions (nair et al., 2014). it is a mixture of char and ash, but it is mainly (7095%) carbon rich material. biochar have good effects on some soil physical properties such as reducing soil bulk density (mukherjee and lal, 2013 and mankasingh et al., 2011), increases the water retention capacity (karhu et al., 2011 and vaccari et al., 2011) and increases soil ph, ec, cec of acidity soil (abewa et al., 2014) and reduces the necessity of inorganic fertilizers. biochar also can be a direct source of nutrients for plants which contains n, p, k, ca, mg, s and micronutrient. mollick et al. (2020) reported that, the yield and processing quality of potato have been 64 roy et al. significantly influenced by the application of 7 t ha-1 of biochar in potato field. so, considering beneficial effect of biochar, the present investigation was undertaken to observe the performance of potato varieties for processing purposes under biochar treatments. materials and methods the experiment was conducted at the agronomy research field, sher-e-bangla agricultural university, dhaka-1207 situated at 23°771116 min. north latitude and 90°375884 min. east longitude at an altitude of 8.6 meter above the sea level (anon., 2004) during the period from november, 2020 to april, 2021.top soil was silty clay in texture, soil ph was 5.6 and has organic carbon of 0.45%. the experiment was consisted of two factors, i.e., factor a:potato varieties (3): v1: bari alu-29 (courage), v2: bari alu-28 (lady rosetta) and v3: bari alu-25 (asterix); factor b: biochar level (5): b0: 0 t ha-1, b1: 2.50 t ha-1, b2: 5.00 t ha-1 and b3: 7.50 t ha-1 and b4: 10 t ha-1. experiment was laid out in a factorial randomized complete block design (rcbd) with 3 replications. certified grade sprouted potato tubers were used as planting material. the experimental plot was fertilized by recommended doses of urea 325kg ha-1, triple super phosphate (tsp) 200kg ha1, gypsum 100 kg ha-1, zinc sulphate 8 kg ha-1mondal et al. (2011).the total amount of biochar was applied at 7 days before planting as per treatment. seed tubers (50-60 g) were planted at 4-5cm depth in soil on november 11, 2020. all other intercultural operations and plant protection measures were taken as per when needed. harvesting of potato was done on february 19, 2021 at 7 days after haulm cutting. the potatoes of each plot were separately harvested, bagged and tagged and brought to the laboratory. all yield and quality contributing parameters were recorded as per treatments. on the basis of weight, the tubers have been graded into marketable tuber (>20g) and non-marketable tuber (<20g). marketable tubers were again separated into canned potato (20-35 mm) dehydrated potato (35-45 mm), chips potato (45-75 mm) and french fries potato (>75 mm) as per processing category (marwaha et al., 2010).the data obtained for different characters were statistically analyzed following the analysis of variance techniques by using mstat-c computer package program. the significant differences among the treatment means were compared by least significant difference (lsd) at 5% level of probability (gomez and gomez, 1984). results and discussion potato yield: potato yield was significantly (p≤0.05) influenced by varietal variation and/or biochar level (figures 1, 2 & table 1). results of figure 1 showed that, the v3 produced maximum yield followed by v1 and v2 produced the minimum one. bari alu-25 produced 20.79 % higher yield more potato than bari alu-28. this might be due to genetic potentiality of potato cultivars. the results of our findings were also in line with the findings of youseef et al. (2017) and vakis (1990) who found that potato yield varied with varietal variation. the yield of potato progressively increased with increasing biochar levels (figure 2). the 32.06 % higher yield was obtained from b4 than b0. the higher yield might be attributed to vigorous plant growth, more tubers hill-1 and large sized tuber. biochar as a soil conditioner it may have increased soil fertility, reduced nutrient leaching, increased microbial activity in soil, improved water holding capacity, and cation exchange capacity in both sandy and clay soils which facilitated better photosynthetic activities, partitioning of photosynthates to the sink (storage organ potato tuber) consequently increased yield and quality of crops. this may also be because biochar serves as a carrier substrate for nitrogen (n) and other mineral nutrients which increase the effectiveness of biochar by retaining and preventing the leaching of n beyond the reach of plants the results of our findings were accordance with those of youseef et al. (2017), ding et al. (2016), yang et al. (2015), who reported that biochar application enhanced the yield of potato. potato yield was also significantly influenced by the interaction effect of variety and biochar level (table 1). the highest potato yield (27.33 t ha-1) was obtained from the v3b4 which was statistically similar to v3b3, v3b2 and enhancement the productivity of processing category potato 65 v1b4 and the lowest (17.78 t ha-1) was obtained from the v2b0. treatment combination v3b4 produced 53.71% higher yield than v2b0. v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 1. effect of variety on the potato yield (lsd 0.05=1.46) b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 8.0 t ha-1 fig. 2. effect of biochar on the potato yield (lsd 0.05=1.89) marketable potato yield: marketable potato yield (>20 g) was significantly (p≤0.05) differed by different potato varieties (figure 3). results revealed that, the treatment v3 produced the maximum marketable potato followed by v1 and v2whereas minimum. v3 produced 11.79 % higher marketable potato than v2. biochar level had significant influenced on the marketable potato yield (figure 3). v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 3. effect of variety on the marketable potato yield (lsd 0.05=0.98) b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 10.0 t ha-1 fig. 4. effect of biochar on the marketable potato yield (lsd 0.05=1.27) results revealed that, marketable potato yield gradually increased with increasing biochar levels and b4 produced maximum marketable potato which was statistically at par with b3 and b2 and 21.58 % higher marketable potato yield was obtained from the plot treated with 10 t ha-1 biochar (b4) than without biochar (b0).gautam et al. (2017), reported that higher levels of the biochar amended soils could be due to improved availability of phosphorous as a result of biochar addition which also could be the reason for better production of marketable potato. collins et al. (2013) also reported that increased biochar application had increased quality potato tuber. youseef et al. (2017) reported that marketable yield was significantly increased with increasing biochar application rates up to 5 m3fed-1. marketable potato yield was significantly differed by the interaction effect of variety and biochar level (table 1). the maximum marketable potato yield (21.30 t ha-1) was obtained from the v3b4 which was 0 6 12 18 24 30 v1 v2 v3 p o ta to y ie ld ( t h a -1 ) variety 0 6 12 18 24 30 b0 b1 b2 b3 b4 p o ta to y ie ld ( t h a -1 ) different levels of biochar 16 17 18 19 20 v1 v2 v3 m a rk e ta b le p o ta to y ie ld (t h a -1 ) varieties 0 5 10 15 20 25 b0 b1 b2 b3 b4 m a rk e ta b le p o ta to y ie ld (t h a -1 ) different levels of biochar 66 roy et al. statistically at par with v3b3, v3b2, v1b2, v1b3 and v1b4 and the lowest marketable potato yield (15.61 t ha-1) from the v2b0 treatment combination which was statistically at par with v1b0, v1b1, v2b1, v2b2 and v3b0. treatment combination v3b4 produced 36.45 % more marketable potato than treatment combination v2b0. these results agree with those reported by nair et al. (2014) who found that marketable potato yield increased with increasing biochar. table 1. interaction effect of variety and biochar on the yield characters of potato treatment combinations potato yield (t ha-1) marketable potato yield (t ha-1) v1b0 19.15 g-i 16.45 de v1b1 20.04 f-i 17.50 c-e v1b2 22.83 c-f 19.52 a-c v1b3 23.59 b-e 19.97 ab v1b4 25.70 a-c 20.24 ab v2b0 17.78 i 15.61 e v2b1 18.41 hi 16.52 de v2b2 20.41 e-i 17.75 c-e v2b3 21.75 d-g 18.52 b-d v2b4 23.84 b-d 18.97 bc v3b0 21.28 d-h 17.69 c-e v3b1 23.49 b-e 18.55 b-d v3b2 25.05 a-c 19.50 a-c v3b3 26.29 ab 20.58 ab v3b4 27.33 a 21.30 a lsd (0.05) 3.27 2.19 cv (%) 8.71 7.05 v1: bari alu-29 (courage), v2: bari alu-28 (lady rosetta) and v3: bari alu-25 (asterix); b0: 0 t ha-1, b1: 2.50 t ha1, b2: 5.00 t ha-1, b3: 7.50 t ha-1 and b4: 10 t ha-1. in a column the mean having the same letter(s) don’t differ significantly at 5% level of [probability canned potato yield: potato variety showed significant difference on canned potato yield (figure 5). the highest canned potato (6.74 t ha-1) was produced by the v2and the lowest canned potato (3.09 t by the v3. biochar levels exerted significant difference on canned potato yield (figure 6). the highest canned potato (6.04 t ha-1) was produced by the b4 and the lowest canned potato (3.96 t ha-1) by the treatment b0. interaction effect of variety and different biochar levels exerted significant difference on canned potato yield (table 2). the highest canned potato (8.10 t ha-1) was produced by the treatment combination v2b4 and the lowest canned potato (2.46 t ha-1) was produced by the treatment combination v3b0 which was statistically similar with v3b1. v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 5. effect of variety on the canned potato yield b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 10.0 t ha-1 fig. 6. effect of biochar on the canned potato 0 2 4 6 8 v1 v2 v3 c a n n e d p o ta to y ie ld ( t h a -1 ) varieties 0 2 4 6 8 b0 b1 b2 b3 b4 c a n n e d p o ta to y ie ld ( t h a -1 ) different levels of biochar enhancement the productivity of processing category potato 67 (lsd 0.05=0.34) yield (lsd 0.05=0.44) dehydrated potato yield: dehydrated potato yield was significantly (p≤0.05) differed by the varietal difference (figure 7). the highest dehydrated potato yield (6.39 t ha-1) was recorded from the v2 followed by v1 (6.35 t ha-1) whereas the lowest one (4.67 t ha-1) was recorded from v3. dehydrated potato yield was significantly differed by the different biochar levels (figure 8). the highest dehydrated potato yield (6.94 t ha-1) was recorded from the b4 whereas the lowest one (4.74 t ha-1) was recorded from b2. v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 7. effect of variety on the dehydrated potato yield (lsd 0.05=0.49) b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 10.0 t ha-1 fig. 8. effect of biochar on the dehydrated potato yield (lsd 0.05=0.63) dehydrated potato yield was significantly differed by the interaction effect of variety and biochar levels (table 2). the highest dehydrated potato yield (10.09 t ha-1) was recorded from the treatment combination v2b4 whereas the lowest one (4.04 t ha-1) was recorded from v3b2 which was statistically similar with v3b4, v3b3, v3b1 and v2b2. chips potato yield: potato variety exerted significant influence on chips potato yield (figure 9). the highest chips potato (7.19 t ha-1) was produced by the v3 and the lowest chips potato (3.61 t ha-1) was produced by the v2.biochar levels employed significant influence on chips potato yield (figure 10). the chips potato yield gradually increased with increasing biochar level.the highest chips potato (6.82 t ha-1) was produced by the b4 and the lowest (3.94 t ha-1) by the treatment b0. interaction effect of variety and different biochar levels exerted significant influence on chips potato yield (table 2). the highest chips potato (9.03 t ha-1) was produced by the treatment combination v3b4and the lowest chips potato (2.08 t ha-1) was produced by the treatment combination v2b0.increases chips potato yield has been attributed to better water holding capacity, higher cation exchange capacity, increased aeration, increased nutrient retention and the ability of biochar to reduce bulk-density. nair et al. (2014) stated similar comments regarding chips potato yield. 0 1 2 3 4 5 6 7 v1 v2 v3 d e h y d ra te d p o ta to y ie ld ( t h a -1 ) varieties 0 2 4 6 8 b0 b1 b2 b3 b4d e h y d ra te d p o ta to y ie ld ( t h a -1 ) different levels of biochar 68 roy et al. v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 9. effect of variety on the chips potato yield (lsd 0.05=0.38) b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 10.0 t ha-1 fig. 10. effect of biochar on the chips potato yield (lsd 0.05=0.50) french-fry potato yield: french-fry potato yield was significantly influenced by the potato variety (figure 23). the highest french-fry potato yield (4.32 t ha-1) was recorded from the v3 and both the variety v1 and v2 did not produce any french-fry potato. french-fry potato yield was significantly influenced by the different biochar levels (figure 24). the results also revealed that french-fry potato yield increased with increasing biochar level. the highest french-fry potato yield (1.90 t ha-1) was recorded from the b4treatment whereas the lowest (0.99 t ha-1) from b0 treatment. the increase in yield of potato for french fry production with the application of biochar could be attributed to corresponding increase in leaf area, which was responsible for synthesizing photosynthesis and increase in tuber weight (youseef et al., 2017). v1: bari alu-29, v2: bari alu-28 and v3: bari alu-25 fig. 11. effect of variety on yield of potato for french fry production (lsd 0.05=0.24) b0: 0 t ha-1, b1: 2.5 t ha-1, b2: 5.0 t ha-1, b3: 7.5 t ha-11 and b4: 10.0 t ha-1 fig. 12. effect of biocharon yield of potato for french fry production (lsd 0.05=0.30) french-fry potato yield was significantly influence by the interaction effect of variety and different biochar levels (table 2). the highest french-fry potato yield (5.70 t ha-1) was recorded from the treatment combination v3b4whereas v1 and v2 in combination with all the biochar levels did not produce any french-fry potato. table 2. interaction effect of variety and biochar on yield of potato for different processing purpose treatment combinations yield for canned potato production (t ha-1) yield for dehydrated potato production yield (t ha-1) yield of potato for chips production (t ha-1) yield of potato for french fry production 0 2 4 6 8 v1 v2 v3c h ip s p o ta to y ie ld ( t h a -1 ) varieties 0 2 4 6 8 b0 b1 b2 b3 b4 c h ip s p o ta to y ie ld ( t h a -1 ) different levels of biochar 0 1 2 3 4 5 v1 v2 v3 f re n ch f ry p o ta to y ie ld (t h a -1 ) varieties 0.0 0.5 1.0 1.5 2.0 b0 b1 b2 b3 b4 f re n ch f ry p o ta to y ie ld ( t h a 1 ) different levels of biochar enhancement the productivity of processing category potato 69 (t ha-1) v1b0 3.87 fg 5.64 cd 4.43 f-h nf v1b1 4.43 ef 7.22 b 5.09 ef nf v1b2 4.70 e 5.62 cd 5.52 e nf v1b3 5.82 cd 6.75 b 5.73 de nf v1b4 6.48 c 6.49 bc 6.55 cd nf v2b0 5.55 d 5.47 cd 2.08 j nf v2b1 6.38 c 6.44 bc 3.15 i nf v2b2 6.40 c 4.56 d-f 3.71 hi nf v2b3 7.26 b 5.41 cd 4.23 gh nf v2b4 8.10 a 10.09 a 4.88 e-g nf v3b0 2.46 h 5.21 de 5.30 e 2.98 c v3b1 2.57 h 5.05 d-f 6.47 cd 4.06 b v3b2 3.42 g 4.04 f 7.19 bc 4.29 b v3b3 3.44 g 4.82 d-f 7.95 b 4.55 b v3b4 3.54 g 4.23 ef 9.03 a 5.70 a lsd (0.05) 0.76 1.09 0.86 0.53 cv (%) 9.18 11.19 9.46 21.87 in a column the mean having the same letter(s) don’t differ significantly at 5% level of probabilityv1: bari alu-29 (courage), v2: bari alu-28 (lady rosetta) and v3: bari alu-25 (asterix); b0: 0 t ha-1, b1: 2.50 t ha-1, b2: 5.00 t ha-1, b3: 7.50 t ha-1 and b4: 10 t ha-1. nf means not found. conclusion from the above findings, it may be concluded that biochar had significant positive role on potato production. the marketable yield, canned, chips and french fry category potato yield sharply increased with increasing biochar level. among the treatment combinations, bari alu-25 and bari alu-29 with biochar level from 5 to 10 t ha-1 produced significantly higher yield (19.50 to 21.30 t ha-1) than other combinations which are 18.54 to 36.45% higher than without biochar. the combination of v2b4 produced maximum canned (8.10 t ha-1) and dehydrated potato (10.09t ha-1) but v3b4 made significantly maximum chips (9.03 t ha-1) and french fry (5.70 t ha-1) category potato, whereas, no french fry category potato was found from bari alu-29 and bari alu-28 it may be concluded that potato growers could apply biochar along with recommended rate of other fertilizers for producing maximum processing category potato. acknowledgements this study was supported by the grant of advanced research in education (gare), bangladesh bureau of educational information and statistic (banbeis), ministry of education, government of the people`s republic of bangladesh. references abewa, a., b. yitaferu, y.g. selassie and t. amare. 2014. the role of biochar on acid soil reclamation and yield of teff (eragrostistef [zucc] trotter) in northwestern ethiopia. j. agric. sci.6(1): 1-12. anonymous. 2004. effect of seedling throwing on the grain yield of wart land rice compared to other planting methods.crop soil water management program agronomy division, brri, gazipur 1710. p.56. chan, k., l. van zwieten, i. meszaros, a. downie and s. joseph. 2008. agronomic values of green waste biochar as a soil amendment. soil res. 45: 629-634. collins, h.p., j. streubel, a. alva, l. porter and b. chaves. 2013. phosphorus uptake by potato from biochar amended with anaerobic digested dairy manure effluent. agron. j. 105(4): 989-998. 70 roy et al. cornelissen, g., v. martinsen, v. shitumbanuma, v. alling, g.d. breedveld, d.w. rutherford, m. sparrevik, s.e. hale, a. obia, j. mulder, p.o. boxand w.r. division. 2013. biochar effect on maize yield and soil characteristics in five conservation farming sites in zambia. pp.256-274. ding, y., y. liu, s. liu, z. li, x. tan, x. huang, g. zeng, l. zhou and b. zheng. 2016. biochar to improve soil fertility. a review. agron. sust. dev. 36(2): 1-18. dou, l., m komatsuzaki, and m. nakagawa. 2012. effects of biochar, mokusakueki and bokashi application on soil nutrients, yields and qualities of sweet potato. int. res. j. agril. sci. soil sci.2(8): 318-327. faostat.2019. statistical database. food and agricultural organization of united nations, rome, italy. food agric. 80: 810-820. gautam, d.k., r.m, bajracharya and b.k. sitaula. 2017. biochar amendment of soil and its effect on crop production of small holder farms in rasuwa district of nepal. int. j. agric. environ. biores. 2(2): 120-135. gomez, k.a. anda.a. gomez. 1984. statistical procedure for agricultural research. second edn. intl. rice res. inst., john wiley and sons. new york. pp.1-340. hunt, j., m. duponte, d. sato and a. kawabata. 2010. the basics of biochar: a natural soil amendment. soil crop manag. 30(7): 1-6. kang, s.w., j.w. park, d.c. seo, y.s. ok, k.d. park, i.w. choi and j.s. cho. 2016. effect of biochar application on rice yield and greenhouse gas emission under different nutrient conditions from paddy soil. j. environ. eng. 142: 1-7. karhu, k., t. mattila, i. bergström and k. regina. 2011. biochar addition to agricultural soil increased ch4 uptake and water holding capacity-results from a short-term pilot field study. agric. ecosyst. environ. 140(1-2): 309-313. mankasingh, u., p. choi and v. ragnarsdottir. 2011. biochar application in a tropical, agricultural region: a plot scale study in. appl. geochem. 26: 218-221. marwaha, r.s., s.k. pandey, d. kumar, s.v. singh and p. kumar. 2010. potato processing scenario in india: industrial constraints, future projections, challenges ahead and remedies-a review. j. food sci. technol. 47(2): 137-156. mollick, m.o.a., a.k. paul, i. alamand m.m. sumon. 2020. effect of biochar on yield and quality of potato (solanum tuberosum l.) tuber. intl. j. bio. stress manag. 11(5): 445-450. mondal, m.r.i., m.s. islam, m.a.b. jalil, m.m. rahman, m.s. alam and m.h.h. rahman. 2011.krishiprojuktihatboi (handbook of agro-technology), 5th edition. bangladesh agricultural research institute, gazipur-1701, bangladesh. p.307. mukherjee, a. and r. lal. 2013. biochar impacts on soil physical properties and greenhouse gas emissions. pp.313-339. mukherjee, a. and a.r. zimmerman. 2013. organic carbon and nutrient release from a range of laboratoryproduced biochars and biochar–soil mixtures. geoderma.193: 122-130. nair, a., r.a.j.l. kruse, tillman and v. lawson. 2014.biochar application in potato production. iowa state res. farm prog. rep. 2027. pp.17-21. novak, j.m., i., lima, b. xing, j.w. gaskin, c. steiner, k. das, m. ahmedna, d. rehrah, d.w. watts and w.j. busscher. 2009. characterization of designer biochar produced at different temperatures and their effects on a loamy sand. ann. environ. sci. 3: 195-206. vaccari, f.p. 2015. biochar stimulates plant growth but not fruit yield of processing tomato in a fertile soil. agric. ecosyst. environ. 207: 163-170. vakis, n.j. 1990. evaluation of potato varieties and clones. miscellaneous rep. 38, agric. res. inst., ministry of agric. and nat. resources, nicosia, cyprus. yang, y., s. ma, y. zhao, m. jing, y. xu and j. chen. 2015. a field experiment on enhancement of crop yield by rice straw and corn stalk-derived biochar in northern china. sustainability. 7: 1371313725. enhancement the productivity of processing category potato 71 yilangai, r.m., s.a. manu, w. pineau, s.s. mailumo and k.i. okekeagulu. 2014. the effect of biochar and crop veil on growth and yield of tomato (lycopersicum esculentus mill) in jos, north central nigeria. curr. agric. res. 2(1): 37-42. yooyen, j., s. wijitkosum and t. sriburi. 2015. increasing yield of soybean by adding biochar. j. environ. res. develop. 9(4): 1066-1074. youseef, m.e.a., i.a.s. al-easily and d.a.s. nawar. 2017. impact of biochar addition on productivity and tubers quality of some potato cultivars under sandy soil conditions. egypt j. hort. 44(2): 199 -217. zheng, h., z.y. wang, x. deng, s. herbert and b. xing. 2013. impacts of adding biochar on nitrogen retention and bioavailability in agricultural soil. geoderma. 206:32-39 enhancement the productivity of processing category potato by biochar gomez, k.a. anda.a. gomez. 1984. statistical procedure for agricultural research. second edn. intl. rice res. inst., john wiley and sons. new york. pp.1-340. bangladesh agron. j. 2021, 24(2): 31-41 performance of sesame(sesamumindicum l.) varieties under varied nutrient levels m. malek1, m.h. ali2, m.f. karim3, m.j. ullah3, a.k. paul4 and s.m. masum3 1farm management wing, 3department of agronomy, 4department of soil science, sher-e-bangla agricultural university, 2fast capital university of bangladesh corresponding e-mail: smmasum607@sau.edu.bd (received: 01 august 2021, accepted: 27 september 2021) keywords: sesame, nutrient levels, varieties, high yield, bangladesh abstract the study was carried out to evaluate some sesame varieties under different nutrient levels for enhancing the productivity of sesame during march – june, 2014. the experiment was carried out in a split-plot design with three replications. the main -plot treatments had four nutrient levels viz., 75% of the recommended dose of fertilizer(rdf), 100% rdf, 125% of rdf, and 150% of rdf, and the sub plot treatments included six sesame varieties viz., laltil (local), atshira (local), t6, bari til-3, bari til-4 and binatil-2. rdf indicates a nutrient schedule of 56:72:23 kg n, p2o5, and k2o ha-1. the effect of nutrient levels, varieties, and their interaction showed significant variation in respect of yield contributing parameters, yield, and harvest index. results revealed that in nutrient levels, 100% of rdf produced the highest seed yield (1223 kg ha-1). the least seed yield was observed with 150% of rdf (924 kg ha-1). among the sesame varieties,bari til-4 showed the optimum growth and yield contributing parameters as a result highest seed yield (1170 kg ha-1). the lowest seed yield was obtained from laltil (811.30 kg ha-1). the interaction effect was found significant where highest seed yield of 1481 kg ha-1 with 100% of rdf combination of sesame var. bari til-4. introduction sesame (sesamumindicum l.) commonly known as til in bengali, belongs to the sesamum genus of the pedaliaceae family. it is grown mainly for seeds that contain 46% 64% oil and 20% protein (raja et al., 2007). sesame oil contains good quality poly-unsaturated fatty acids viz., 47% oleic and 39% linoleic acid. the crop is cultivated either as a pure stand or as a mixed crop with aus rice, jute, groundnut, millets, and sugarcane. in bangladesh, sesame occupies a remarkable area under production and contributes second-ranked production after rapeseed and mustard. although at present about 3, 21,338hectares of land are under sesame cultivation with a production of 19795 metric tons (bbs, 2020) but land area and production under sesame cultivation is decreasing day by day. in 2009-10, about 36 thousand hectares of land were under sesame cultivation where total production was 32306 metric tons (bbs, 2010). however, the climatic and edaphic conditions of bangladesh are quite suitable for the cultivation ofsesame. khulna, jashore, faridpur, barisal, patuakhali, rajshahi, pabna, rangpur, sylhet, cumilla, dhaka, and mymensingh districts are the leading sesame producing areas of bangladesh. lack of acclimatizing high yielding varieties, poor crop stand establishment, capsule shattering, uneven ripening, lesser fertilizer retorts, abundant branching, indeterminate growth habit, truncated harvest index, and vulnerability to diseases are the restrictivereasons in sesame production worldwide (tripathy et al., 2019). however, the environmental conditions, agricultural operations such as nutrition, and varieties have an impacton sesame seed yield and its harvest index (bedigian et al., 1985). this probably indicates a great opportunity for a prolonged and higher increase in the 32 malek et al. productivity of sesame. to increase the productivity of sesame, various improved technologies are needed and among them, various agro-techniques, isolating location-specific varieties assumes greater significance (myint et al., 2020). in particular, variety, sowing time, population density and/or plant spacing, and fertilizermanagement in the soil play significant roles as determinants of seed yield. there are several modern varieties available in bangladesh; but, the farmers are continuing to grow local varieties. besides, inappropriate use of fertilizers is one of the major production constraints. therefore, adoption of sustainable variety and maintenance of nutrient status in the soil would fulfill the maximizing yield of sesame (monayem et al., 2015). higher productivity in any crop can be achieved through a combination of ideal variety associated with appropriate nutrient management practices.besides, without or little use of fertilizers for sesame is a common practice in in bangladesh. keeping all the above facts, the study was undertaken to comparethe varietiesalong with the fertilizer management on sesame growth performance and productivity. materials and methods the experiment was carried out at the research field of the agronomy department, sher-e-bangla agricultural university, dhaka during march-june 2014. the experimental field was located at 90° 33′ e longitude and 23° 71′ n latitude at a height of 9 m above the sea level. the climate of the experimental area was sub-tropical and characterized by high temperature, heavy rainfall during kharif-1 season (march-june), and scanty rainfall during rabi season (october-march) associated with moderately low temperature (khanam et al., 2016). the land belongs to the agro-ecological zone “madhupur tract” (aez-28) having the red brown trace soils of tejgaon series. the soil of the experimental site was well-drained and medium-high. the physical and chemical properties of the soil of the experimental site are silty clay in texture and having soil ph varied from 5.45-5.61. organic matter content was very low (0.83). the soil physical components such as sand, silt, clay content were26%, 45%, and 29%, respectively, organic carbon 0.45, total n 0.61%, k 0.11 meq 100g soil-1, and p, s, b, and zn 0.65, 7.74, 0.35 and 3.99 µgg-1 ppm, respectively. the experiment consisted of split-plot design where nutrient levels was placed in main – plot and variety in subplot (table 1). laltil variety was collected from ullapara, sirajgonj where atshira variety from khoksha, kushtia, and rest varieties. t6, (bari til-3, and bari til-4) from bangladesh agricultural research institute (bari), joydeppur, gazipur. the variety binatil 2 was collected from the bangladesh institute of nuclear agriculture (bina). the treatments in main –plot were nutrient levels viz. n1 = 75% of rdf(43:54:23 kg n, p2o5 and k2o ha-1) n2 = 100% of rdf(58:72:30 kg n, p2o5 and k2o ha-1) n3 = 125% of rdf(72:90:38 kg n, p2o5 and k2o ha-1) n4 = 150% of rdf(86:108:45 kg n, p2o5 and k2o ha-1) and sub plot treatments were as v1 = laltil (local), v2 = atshira (local) v3 = t-6 v4 = bari til-3 v5 = bari til-4 v6 = binatil 2 the fertilizers used in the study were urea, tripple superphosphate (tsp), and muriate of potash (mop) to supply n, p, and k, respectively (frg, barc, 2012). before sowing seeds, the percentage of germination was found over 95. row spacing was 30 cm with seed rate 5 kg /ha. seeds were placed 23 cm depth in rows and seeds were covered with loose soil properly. the thinning operation was done for ensuring the optimum plant populations. all other recommended agronomic practices were followed (bari, 2013). regular observations were made to observe the growth stages of the crop. the data collected on different parameters were statistically analyzed by using the mstatc computer performance of sesame(sesamumindicum l.) varieties 33 package program and treatment means were compared by lsd test at 5% level of probability (gomez and gomez, 1984). results and discussion effect of nutrient levels on yield attributes a significant variation was observed for the number of capsule plant-1, number of seeds capsule-1, capsule length, and weight of 1000seedsdue to the application of different nutrient levels on sesame (table 2). regarding nutrient levels, the number of capsules plant-1 was maximum (77.28) from 100% of rdf (n2) followed by n3 (125% of rdf). lower number of capsule plant-1 (63.83) was recorded from 75% of rdf (n1) which was statistically similar with n4 (150% of rdf). bennet et al. (1996) also found an increased number of capsules plant-1 with napplication up to 120 kg ha-1. each successive increase in the dose of n up to 60 kg ha-1 significantly increased the capsules plant-1 (prakash et al., 2001). nahar et al. (2008) indicated that the number of capsules plant-1 increased significantly up to 100 kg n ha-1. significantly higher seed yield was recorded with 50 kg p2o5 ha-1 due to an increase in capsules plant-1 (prakasha and thimmegowda, 1992). mian et al. (2011) opined that the highest number of capsules plant-1 was recorded with 90 kg p2o5 ha-1. increasing the level of k from 100 to 150 percent of the recommended dose, the number of capsules plant-1 of sesamum increased significantly (subrahmaniyan et al., 2001).the number of seeds capsule-1 was maximum (79.53) from 100% of rdf (n2) followed by n3 (125% of rdf). the lowest number of seeds capsule-1 (72.76) was recorded from 150% of rdf (n4) which was statistically similar with n1 (125% of rdf). nahar et al. (2008) also indicated that the seeds capsule-1 increased significantly up to 100 kg n ha-1. kathiresan (1999) indicated that the p level of 35 kg ha-1 influenced the number of seeds capsule-1 of sesamum. application of potassium markedly increased the number of seeds capsule-1 (mandal et al., 1992). tiwari et al. (1994) was found that the application of k2o significantly increased the seeds capsule-1 of sesamum. the capsule length was maximum (3.19 cm) from 100% of rdf (n2) followed by n3 (125% of rdf). the lowest capsule length (2.13 cm) was recorded from 150% of rdf (n4) which was statistically similar with n1 (75% of rdf). mian et al. (2011) opined that the highest capsule length was recorded with 90 kg p2o5 ha-1 compared to 70 and 110 kg p2o5 ha-1. tiwari et al. (1994) was found that the application of k2o significantly increased the capsule length of sesame. the weight of 1000-seeds was highest (2.78 g) from 100% of rdf (n2) followed by n3 (125% of rdf). the lowest weight of 1000seeds (2.60 g) was recorded from 75% of rdf (n1) which was statistically similar with n4 (150% of rdf). ghosh and patra (1994) recorded a higher 1000 -seeds weight of sesamum upto 60 kg n ha-1. each successive increase in the dose of n up to 60 kg ha-1 significantly increased 1000 -seeds weight (prakash et al., 2001). nahar et al. (2008) indicated that the 1000seeds weight increased significantly up to 100 kg n ha-1. mian et al. (2011) opined that the highest 1000 seeds weight was recorded with 90 kg p2o5 ha-1. application of potassium markedly increased the 1000seeds weight (mandal et al., 1992). prakasha and thimmegowda (1992) reported 53 percent increased seed yield with higher n rate due to enhanced value of yield attributes viz., capsules plant-1, number of seeds capsule-1, capsule length, and weight of 1000 -seeds. performance of varieties in terms of yield attributes the tested local and modern varieties of sesame varied significantly in number of capsule plant-1, number of seeds capsule-1, capsule length, and weight of 1000seeds (table 2). the maximum number of capsule plant-1(77.33) was obtained from v5 (bari til-4) followed by v4 (bari til-3). table 2. effect of nutrient levels, variety, and their interaction on yield contributing parameters of sesame treatment yield contributing parameters number of capsule plant-1 number of seeds capsule-1 1000 -seeds weight (g) capsule length (cm) nutrient levels 34 malek et al. n1 63.83 c 73.05 c 2.60 c 2.18bc n2 77.28 a 79.53 a 2.78 a 2.32 a n3 69.11 b 75.69 b 2.70 b 2.24 b n4 64.28 c 72.76 c 2.62 c 2.13 c lsd0.05 1.21 1.41 0.04 0.06 varieties v1 56.58 f 65.82 e 2.45 c 2.05 c v2 59.17 e 69.03 d 2.52 c 2.12 b v3 70.25 d 77.66 c 2.73 b 2.26 a v4 76.08 b 79.67 b 2.79ab 2.30 a v5 77.33 a 80.76 a 2.81 a 2.31 a v6 72.33 c 78.62 c 2.75ab 2.28 a lsd0.05 0.93 0.97 0.07 0.05 combination of nutrient levels and varieties n1v1 58.67jk 68.30hij 2.47 h 2.15ghi n1v2 63.67 hi 72.77 g 2.60 fg 2.17gh n1v3 64.67ghi 72.90 g 2.63 fg 2.17gh n1v4 65.00gh 75.57fg 2.63 fg 2.20fg n1v5 66.33fgh 75.80fg 2.63 fg 2.23ef n1v6 64.67ghi 72.97 g 2.63 efg 2.20fg n2v1 56.33 kl 67.47hij 2.47 h 2.13 hi n2v2 61.67ij 69.43 h 2.53 gh 2.16gh n2v3 76.67 c 82.33bc 2.87 b 2.36bc n2v4 93.00 a 85.33ab 2.97 a 2.42 a n2v5 94.67 a 88.13 a 3.00 a 2.43 a n2v6 81.33 b 84.50 b 2.87 b 2.41ab n3v1 56.00 kl 65.97ij 2.43 h 2.10 i n3v2 59.67 j 68.77 hi 2.50 h 2.15ghi n3v3 72.00 d 78.40def 2.80 bc 2.27 e n3v4 75.33 c 80.10cde 2.83 bc 2.32 cd n3v5 76.67 c 81.20 cd 2.83 bc 2.35 c n3v6 75.00 c 79.70 cd 2.80 bc 2.28 de n4v1 55.33 l 61.53 k 2.43 h 1.82 k n4v2 51.67 m 65.17 j 2.43 h 2.02 j n4v3 67.67fg 77.00ef 2.63 efg 2.23ef n4v4 71.00 de 77.67ef 2.73 cde 2.24ef n4v5 71.67 d 77.90def 2.77bcd 2.24ef n4v6 68.33ef 77.30ef 2.70 def 2.24ef lsd0.05 2.975 3.026 0.090 0.052 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. note: n1= 75% of rdf (43:54:23 kg n, p2o5 and k2o ha-1), n2= 100% of rdf (58:72:30 kg n, p2o5 and k2o ha-1), n3= 125% of rdf (72:90:38 kg n, p2o5 and k2o ha-1), n4= 150% of rdf (86:108:45 kg n, p2o5 and k2o ha-1); v1 = laltil (local), v2 = atshira (local), v3 = t-6, v4 = bari til-3, v5 = bari til-4, v6 = binatil 2 the lowest number of capsule plant-1 (56.58) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). el-serogy et al. (1997), deshmukh et al. (2005), kokilavani et al. (2007), and riaz et al. (2002) indicated that the number of capsules plant-1 differed significantly by different varieties. the maximum number of seeds capsule-1 (80.76) was obtained from v5 (bari til-4) followed by v4 (bari til-3). the lowest number of seeds capsule-1 (65.82) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). variation in the number of seeds capsule-1 was noticed significantly among varieties (govindaraju and balakrishnan, 2002). ali and jan (2014) and chongdar et al. (2015) also observed variation in the number of seeds capsule-1 due to different varietal performance. the maximum capsule length (2.31 cm) was obtained from v5 (bari til-4) performance of sesame(sesamumindicum l.) varieties 35 which was statistically similar with v3 (t-6), v4 (bari til-3), and v6 (binatil 2). the lowest capsule length (2.05 cm) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). riaz et al. (2002) and lakshmi and lakshmamma (2005) also found similar results regarding capsule length of sesame and observed that different varieties showed different capsule lengths. the maximum weight of 1000seeds (2.81 g) was obtained from v5 (bari til-4) which was statistically similar to v4 (bari til-3) and v6 (binatil 2). the lowest weight of 1000 -seeds (2.45 g) was observed from local variety v2 (atshira) which was statistically similar with local varietyv1 (laltil). similar results on 1000seeds weight was found from rao et al. (1990) and yadav et al. (1991) which supported the present findings. they observed that the hyv variety gave a higher 1000 seed weight than the local variety. interaction effect of nutrient levels and varieties on yield attributes results showed that yield attributes due to the combination between different nutrient levels and varieties were significant (table 2). the combination of n2v5 showed the maximum number of capsule plant-1 (94.67) which was statistically similar with n2v4 followed by n2v6. the lowest number of capsule plant-1 was recorded from n4v1 (55.33) which were statistically similar with n3v1and n2v1. the maximum number of seeds capsule-1 (88.13) from the n2v5 combination was statistically similar with n2v4 followed by n2v6. the lowest number of seeds capsule-1 was recorded from n4v1 (61.53) followed by n4v2 and n3v1. the maximum capsule length (2.43 cm) was recorded from n2v5which was statistically similar with n2v4 and closely followed by n2v6. the lowest capsule lengthwas recorded from n4v1 (1.82 cm) followed by n4v2. different varieties had a significant response to different nutrient rates. similarly, the variety t6 and bari til-3 showed increased capsule length up to 100 kg n ha-1 but the variety bari til 2 responded up to 150 kg n ha-1 (nahar et al., 2008).the maximum weight of 1000seeds (3.00 g) was obtained from the n2v5which was statistically similar with n2v4 followed by n2v3 and n2v6. the lowest weight of 1000seeds was recorded from n4v1 (2.47 g) which were statistically similar with n2v1, n3v1, n3v2, n4v1 and n4v2. effect of nutrient levels on yield and harvest index seed yield, stover yield, and harvest index were significantly influenced due to different nutrient levels (fig. 1). seed yield ha-1 was maximum (1223 kg ha-1) from 100% of rdf (n2) followed by n3 (125% of rdf). the lowest seed yield ha-1 (924 kg ha-1) was recorded from 150% of rdf (n4) followed by n1 (75% of rdf). the highest seed yield from 100% of rdf (n2) might be due to the higher number of capsules plant-1, number of seeds capsule-1, capsule length, and 1000 seed weight. jadhav et al. (1992) also reported that the highest grain yield was recorded when 120 kg n and 75 kg p2o5 ha-1 was applied on account of a higher number of capsules plant-1 and number of seeds capsule-1, which was statistically on par with 120 kg n and 50 kg p2o5 ha-1. seed yield increased for every further increase in the rate of n and k application upto 80 and 60 kg ha-1, respectively (mandal et al., 1992). nahar et al. (2008) indicated that the seed yield increased significantly up to 100 kg n ha-1. kathiresan (1999) indicated that the p level of 35 kgha-1 influenced the seed yield of sesamum. 36 malek et al. n1 = 75% of rdf (43:54:23 kg n, p2o5 and k2o ha-1), n2 = 100% of rdf (58:72:30 kg n, p2o5 and k2o ha-1), n3 = 125% of rdf (72:90:38 kg n, p2o5 and k2o ha-1), n4 = 150% of rdf (86:108:45 kg n, p2o5 and k2o ha-1) fig.1. seed yield (a), stover yield (b), and harvest index (c)of sesame as influenced by different levels of nutrients (lsd0.05=13.43, 16.45, and 0.679, respectively) the application of potassium markedly increased the seed yield (mandal et al., 1992). increasing the level of k from 100 to 150 percent of the recommended dose, the seed yield of sesame increased significantly (subrahmaniyan et al., 2001). the stover yield ha-1 was highest (1473 kg ha-1) from 100% of rdf (n2) followed by n3 (125% of rdf). the lowest stover yield ha-1 (1274kg ha-1) was recorded from 75% of rdf (n1) which was followed by n4 (150% of rdf). ali and jan (2014) reported that plots treated with 120 kg n ha-1 produced maximum stover yield (5351 kg ha-1). vaghani et al. (2010) reported that significantly higher stover yields were achieved with the fertilizer application of 100 kg n + 25 kg p2o5 + 80 kg k2o + 40 kg s ha-1. mian et al. (2011) opined that the highest seed and stover yield was recorded with 90 kg p2o5 ha-1.the harvest index was highest (45.36%) from 100% of rdf (n2) followed by n1 (75% of rdf). the lowest harvest index (41.23%) was recorded from 150% of rdf (n4) which was statistically similar with n3 (125% of rdf). ali and jan (2014) reported that 120 kg n ha-1 produced the highest harvest index. khade et al. (1996) indicated that the harvest index increased with up to 50 kg p2o5 ha-1. the highest harvest index was achieved by the application of 44 kg n and 44 kg p2o5ha-1 (abdel, 2008). sarawagi et al. (1995) opined that significant seed yield, stover yield, and harvest index of summer sesame was 60 to 90 kg k2o ha-1. effect of varieties on yield and harvest index significant influence was found for seed yield ha-1, stover yield ha-1, and harvest index (%) by different sesame varieties (figure 2). the maximum seed yield ha-1 (1170 kg ha-1) was obtained from v5 (bari til-4) followed by v4 (bari til-3). the lowest seed yield ha-1(811.30kg ha-1) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). production capacity of yield contributing characters viz. number of capsules plant-1, number of seeds capsule-1, capsule length and weight of 1000seeds was highest compared to other tested variety and resulted in highest seed yield. suryabala et al. (2008) and monpara et al. (2008) also found the yield of sesame varied significantly due to performance of sesame(sesamumindicum l.) varieties 37 different varieties according to producing capability of yield contributing parameters. the maximum stover yield ha-1 (1476kg ha-1) was obtained from v5 (bari til-4) which was statistically similar with v4 (bari til-3) and v6 (bina-til 2) followed by v3 (t-6). the lowest stover yield ha-1 (1139kg ha-1) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). suryabala et al. (2008) and hamdollah et al. (2009) opined that different sesamum cultivars showed a significant variation in stover yield. v1 = laltil (local), v2 = atshira (local), v3 = t-6, v4 = bari til-3, v5 = bari til-4, v6 = binatil 2 fig. 2. seed yield (a), stover yield (b), and harvest index (c) of sesame as influenced by different varieties (lsd0.05=16.44, 14.82, and 0.713, respectively) the maximum harvest index (44.22%) was obtained from v5 (bari til-4) which was statistically similar tov4 (bari til-3). the lowest harvest index (41.60%) was observed from local variety v1 (laltil) followed by local variety v2 (atshira). a similar result was also found by balasubramaniyan et al. (1995) and they opined that different varieties had a significant effect on the harvest index. they also opined that hyv possesses a higher harvest index than the local variety. ali and jan (2014) also found significant variation with sesame varieties on seed yield, stover yield, and harvest index. interaction effect of nutrient levels and varieties on yield and harvest index statistically, significant variation was observed by the combined effect of different nutrients and varieties regarding seed yield ha-1, stover yield ha-1,and harvest index (%) (table 3).results signified that combination between different nutrient levels and varieties, n2v5 listed the maximum seed yield ha-1 (1481 kg ha-1) which was statistically similar with n2v4 followed by n2v6. the lowest seed yield ha-1was recorded from n4v1 (670kg ha-1) which was followed by n4v2.the maximum stover yield ha1(1715kg ha-1) resulted in n2v5which was statistically similar with n2v4 followed by n2v6, n2v3,and n3v5. the lowest stover yield ha-1 was recorded from n4v1(1043kg ha-1) which was followed by n4v2 and n3v1. finally, n2v5showed thatthe maximum harvest index (46.34%) followed by n2v6 and n2v4. the lowest harvest index was recorded from n4v2 (35.87%) followed by n4v1 and n4v5.bhosaleet al. 38 malek et al. (2011) found that sesame cv. ‘gujrattil 2’ reported significantly highest seed yield, stover yield, harvest index with the fertilizer application of 25 kg n + 25 kg p2o5 + 50 kg k2o ha-1. table 3. combined effect of different levels of nutrients and varieties on yield and harvest index of sesame treatment seed yield ha-1 (kg) stover yield ha-1 (kg) harvest index (%) n1v1 908.00 i 1203.00jk 42.85bcde n1v2 965.30 h 1247.00ij 42.66cde n1v3 974.70gh 1280.00ij 44.42 a n1v4 990.70fgh 1317.00gh 41.76 f n1v5 1005.00fg 1343.00 g 40.22 g n1v6 984.00gh 1286.00 hi 41.62 f n2v1 868.00 j 1182.00 k 39.52gh n2v2 961.30 h 1239.00 j 43.53bc n2v3 1161.00 c 1622.00 c 42.10def n2v4 1457.00 a 1706.00 b 43.18bc n2v5 1481.00 a 1715.00 a 36.34 j n2v6 1408.00 b 1664.00 c 42.11def n3v1 798.70 k 1128.00 l 38.91 hi n3v2 958.70 h 1238.00 j 43.62b n3v3 1105.00 d 1512.00 d 42.17def n3v4 1132.00 cd 1530.00 d 41.42 f n3v5 1135.00 cd 1621.00 c 38.15 i n3v6 1120.00 d 1519.00 d 40.32 g n4v1 670.70 m 1043.00 m 36.92 j n4v2 756.00 l 1106.00 l 35.87 k n4v3 1011.0fg 1356.00 g 42.98bcd n4v4 1027.00ef 1468.00ef 39.61gh n4v5 1059.00 e 1489.00 de 39.18 h n4v6 1021.00 f 1438.00 f 42.03ef lsd0.05 33.22 41.16 0.7933 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. note: n1= 75% of rdf (43:54:23 kg n, p2o5 and k2o ha-1), n2= 100% of rdf (58:72:30 kg n, p2o5 and k2o ha-1), n3= 125% of rdf (72:90:38 kg n, p2o5 and k2o ha-1), n4= 150% of rdf (86:108:45 kg n, p2o5 and k2o ha-1); v1 = laltil (local), v2 = atshira (local), v3 = t-6, v4 = bari til-3, v5 = bari til-4, v6 = binatil 2 conclusion the combined effect of nutrient levels, 100% of rdf (58 -7230 kg n p205k20/ ha) with variety. bari til-4produced the highest seed yield (1481 kg ha-1) and oil yield (670 kg ha-1). .hence, it is concluded that the combination of 100% of rdf and var. bari til-4is conductive to produce maximum seed yield (kg ha-1) of sesame in bangladesh. references abdel, r.a.e. 2008. response of sesame to nitrogen and phosphorus fertilization in northern sudan. j. appl. biosci. 8(2): 304-308. balasubramaniyan, p., p. gnanamurthy and v. dharmalingam. 1995. response oj irrigated sesame varieties to planting density and nitrogen. sesame safflower newsl. 10: 59-62. barc (bangladesh agricultural research council). 2012. fertilizer recommended guide, 2013. farmgate, dhaka, bangladesh. performance of sesame(sesamumindicum l.) varieties 39 bari (bangladesh agricultural research institute). 2013. krishiprojuktihatboi (in bengali). bangladesh agricultural research institute, gazipur, bangladesh. pp. 215-225. bbs (bangladesh bureau of statistics). 1996. statistical yearbook of bangladesh. bureau of statistics, statistics division, ministry of planning, govt, of the people's republic of bangladesh. dhaka. bbs (bangladesh bureau of statistics). 2010. statistical yearbook of bangladesh. bureau of statistics, statistics division, ministry of planning, govt, of the people's republic of bangladesh. dhaka. bbs (bangladesh bureau of statistics). 2020. statistical yearbook of bangladesh. bureau of statistics, statistics division, ministry of planning, govt, of the people's republic of bangladesh. dhaka. p.121. bedigian, d., d. s. seigler and j. r. harlan. 1985. sesamin, sesamolin and the original of sesame biochem systematics. biochem. syst. ecol. 13(2):133-139. bennett, m.r.,k. thiagalingam and d.f. beeck. 1996. effect of nitrogen application on growth, leaf nitrogen content, seed yield and yield components of sesame. sesame safflower newsl.11: 21-28. bhosale, n. d., b. m. dabhi, v. p. gaikwad and t. c. poonia. 2011. response of sesamum (sesamumindicum l.) to different levels of potash and sulphur under south saurashtra region. advance res. j. crop impr. 2(1): 121-124. chongdar, s., b. chhetri, s.k. mahato and a. saha. 2015. production potentials and economic feasibility of improved sesame (sesamumindicum l.) cultivars under varying dates of sowing in prevailing agroclimatic condition of north bengal. int. j. agric. sci. 7(2): 434-439. deshmukh, m.r., h.c. jasin and s.s. duhoon. 2005. relative performance of sesame (sesamumindicum l.) varieties in kymore plateau zone of madhya pradesh (india). j. oilseeds res. 22(1): 197-198. el-serogy, s.t., m.a. el-emam and w.a.i. sorour. 1997. the performance of two sesame varieties under difference sowing methods in two locations. ann. agric. sci. 42(2): 355-364. ghosh, d.c. and a.k. patra. 1994. effect of plant density and fertility levels on productivity and economics of summer sesame (sesamumindicum l.). indian j. agron.39(l):71-75. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons, new york. govindaraju, p.k. and balakrishnan. 2002. effect of soil alkalinity on plant growth, yield and oil content of sesamum. madras agric. j.89(1-3): 133-135. hamdollah e., z.s. saeid, g.g. kazem and h.g. mohammad. 2009. effects of water limitation on grain and oil yields of sesame cultivars. j. food agric. environ. 7(2): 339-342. jadhav, a.s., g.v. chavan and s.r. gungarde. 1992. geometry of sesame (sesamumindicum l.) cultivars under rainfed conditions. indian j. agron. 37(4): 857858. jebaraj, s. and m.n. sheriff. 1996. svpr 1 (tss 6): a short duration high yielding white-seeded sesame for tamil nadu. indian fmg. 45(10): 5. kathiresan, g. 1999. effect of growth regulators and clipping on sesame growth and yield in different seasons. sesame safflower newsl. 14: 46-49. khade, v.n., s.n. jadhav and s.a. khanvilkar. 1996. studies on scheduling of irrigation and phosphate fertilization to sesamum. j. maharashtra agric. univ. 21(3): 410-411. khanam, m., m.s. islam, m.h ali., i.f. chowdhury and s.m. masum. 2016. performance of soybean under different levels of phosphorus and potassium. bangladesh agron. j.19: 99-108. kokilavani, s., r. jagannathan and s.k. natarajan. 2007. manual terminal clipping on yield and nutrient uptake of sesame varieties. res. j. agric. biol. sci.3(6): 987-999. lakshmi, p. and p. lakshmamma 2005. growth and yield of sesame (sesamumindicum) as influenced by seasons. j. oilseeds res.22(1):228-230. mandal, s.s., d. verma and s. kuila. 1992. effect of organic and inorganic sources of nutrients on growth and seed yield of sesame (sesamumindicum l.). indian j. agric. sci.62(4): 258-262. mian, m.a.k., m.k. uddin, m.r. islam, n.a. sultana and h. kohinoor. 2011. crop performance and 40 malek et al. estimation of the effective level of phosphorus in sesame (sesamumindicum l.). academic j. plant sci. 4(1): 1-5. monayem, m.a., a. sadia, m.a. rashid and s.a.m. shiblee. 2015. factors affecting adoption of improved sesame technologies in some selected areas in bangladesh: an empirical study. the agriculturists. 13(1): 140-151. monpara, b.a., m.d. vora, b.m. chovatiya and b.v. radadia. 2008. g. til3: a white and bold seeded sesame (sesamumindicum l.) variety for saurashtra region of gujarat. j. oilseeds res.25(2): 186187. myint d., a. syed, gilani, m. kawase and k.n. watanabe. 2020. sustainable sesame (sesamumindicum l.) production through improved technology: an overview of production, challenges, and opportunities in myanmar. sustainability. 12: 3515. doi:10.3390/su12093515 nahar, z., k.k. mistry, a.k. saha and q.a. khaliq. 2008. response of nitrogen levels on yield of sesame (sesamumindicum l.). saarc j. agri.6(1): 1-7. prakash, o.m., b.p. singh and p.k. singh. 2001. effect of weed control measures and nitrogen fertilization on yield and yield attributes of sesamum(sesamumindicum l.) under rainfed condition. indian j. agric. sci.71(9): 610-612. prakasha, n.d. and s. thimmegowda. 1992. effect of irrigation and fertilizer levels on nutrient concentrations and protein yield of sesame (sesamumindicum l.). indian j. agron.37(2): 387-388. raikwar, r.s. and p. srivastva. 2013. productivity enhancement of sesame (sesamumindicum l.) through improved production technologies. african j. agric. res. 8(47): 6073-6078. raja, a., k.o. hattab, l., gurusamy and s.suganya 2007. sulphur levels on nutrient uptake and yield of sesame varieties and nutrient availability. int. j. soil sci. 2: 278-285. rao, k.l., d.v.n. raju and c.p. rao. 1990. response of sesamum varieties to rate and method of nitrogen application under rainfed condition. the andhra agric. j.37(2): 352-356. riaz a., m. tariq, s.m. farrukh and a. shamim. 2002. comparative performance of two sesamum (sesamumindicum l.) varieties under different row spacings. asian j. plant sci.1(5): 546-547. sarawagi, s.k., n. lai, r.s. tripathi and k.k. purohit. 1995. effect of nitrogen, potassium, sulphur on growth and yield of sesame in summer season. ann. agric. res. 16(1): 101-103. subrahmaniyan, k., d. dinakaran, p. kalaiselven and n. arulmozhi. 2001. response of root rot resistant cultures of sesame (sesamumindicum l.) to plant density and npk fertilizer. agric. sci. dig. 21(3): 176-178. suryabala y., a.b. abidi, r.p. singh and a. singh. 2008. response of sulphur nutrition on nutritional characteristics of oil and cake of sesame (sesamumindicum l.) varieties. j. oilseeds res. 25(1): 3840. tiwari, k.p., r.k. jain and r.s. raghuwanshi.1994. effect of sowing dates and plant densities on seed yield of sesame cultivars. crops res. (hisar). 8(2): 404-406. tripathy, s.k., j. kar and d. sahu. 2019. advances in sesame (sesamumindicum l.) breeding. in advances in plant breeding strategies: industrial and food crops. eds. al-khayri, j.m., s.m. jain and d.v. johnson. springer, cham, switzerland. pp. 577–635. vaghani, j.j., k.b. polara, p.k. chovatia, b.v. thumar and k.b. parmar. 2010. effect of nitrogen, potassium and sulphur on yield, quality and yield attributes of kharif sesame (sesamumindicum l.). asian j. soil sci. 5(2): 318-321. yadav, l.n., a.k. keshurwani, b.k. verma and y.d. tiwari. 1991. september sown sesamum gives high yields in madhya pradesh. indian fmg. 41: 34-35. ali, s. and a. jan. 2014. sowing dates and nitrogen level effect on yield and yield attributes of sesame cultivars. peshawar, pakistan: agricultural university peshawar. sarhad j. agric. 30(2): 203-209. bangladesh agron. j. 2022, 25(2): 73-82 foliar application effects of zinc oxide nanoparticles on growth, yield and drought tolerance of soybean d.b. dola and m.a. mannan department of agronomy, bangabandhu sheikh mujibur rahman agricultural university gazipur-1706, bangladesh corresponding e-mail: mannanagr@bsmrau.edu.bd (received: 16 november 2022, accepted: 29 december 2022) keywords: soybean, nano fertilizer, drought mitigation abstract in modern agriculture, the application of nano fertilizers is increasing the productivity and stability of different crops by reducing the destructive effects of abiotic stresses. the nano particles are significant for their particle shape, potential reactivity, tunable pore size and high surface area. a pot experiment was conducted at the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university, gazipur during rabi season (december 2020 to march 2021) to evaluate the effects of foliar spray of nano zinc (zno) in varying doses (0, 100 and 200 ppm) on growth, dry matter accumulation and yield of soybean under drought (40% of field capacity, fc) and control (80% of fc) conditions. the trial was conducted in a completely randomized design (crd) with three replications. plant height; fresh and dry weight of leaf, stem and whole plant; number of pods per plant; number of seeds pod-1; 100-seed weight and seed yield of soybean were suppressed due to drought stress. under both drought and control conditions, the foliar application of nano zinc substantially improved the growth, dry matter accumulation and yield of soybean. in drought condition, the foliar spray of 200 ppm nano zinc solution increased plant height, total fresh and dry weight by 21.69, 34.23 and 76.03%, respectively. in drought conditions, nano zn particles at 100 and 200 ppm increased seed yield by 26.79 and 63.50%, and in control conditions by 13.07 and 23.56%, respectively. as such the results indicated that foliar application of nano zinc oxide improved growth, yield and drought tolerance of soybean. introduction soybean (glycine max) is an annual self-pollinated diploid legume under the family fabaceae. soybean is recognized as an oil seed containing several useful nutrients including protein, carbohydrate, vitamins, and minerals. according to index mundi (2021), the soybean production in 2020 was 156,000 mt and also it has been increased about 44% for last decade in bangladesh. the annual soybean production and imports are increasing gradually to meet the feed requirements for the livestock, poultry and fisheries sectors, and soybean oil for human consumption (usda, 2019). among the abiotic factors, the drought is considered the most devastating, affecting all plants growth and development stages causing huge losses in soybean yield (engels et al., 2017). drought stress is a multidimensional stress and causes changes in the physiological, morphological, biochemical, and molecular traits in plants which ultimately affects negatively on mailto:mannanagr@bsmrau.edu.bd 74 dola et al. yield of plants (salehi-lisar and bakhshayeshan-agdam, 2016). since drought tolerance is a quantitative trait and many genes are involved, it is difficult to create a molecular marker for a plant’s response to a water deficit (sinclair, 2011). furthermore, the timing, intensity, and duration of a drought varies (mir et al., 2012), creating a hurdle for properly testing varieties. therefore, plant breeders typically combine data from multi-location trials to test new varieties, determine how genotypes respond across environments, and minimize effects of genotype by environment interactions (crossa, 1990). the use of nano fertilizers has led to the increased productivity, stability due to reduction of biotic and abiotic stresses as well as reduced production costs in the last decade (kashyap et al., 2016, 2017). according to davar et al. (2014), different trace elements and their oxides of nano particles were used for enhancing drought stress resistance in different plants. additionally, sharifi and khoramdel (2016) was found that foliar application of zn nano particles combined with the inoculum of bradyrhizobium japonicum improved yield of soybean. sheykhbaglou et al. (2010) observed that foliar application of nano-iron oxide at the concentration of 750 ppm increased leaf and pod dry weight over the control. nano particles are characterized by its particle shape, tunable pore size, potential reactivity and high surface area (seleiman et al., 2021). in plants, the cellular organelles are targeted, and certain contents are released through the nano particle target (cunningham et al., 2018). in agriculture, a wide scope of nano technology is still unexplored. above circumstances, the present research was conducted to study the effect of the foliar application of nano zno fertilizer on growth, dry matter accumulation and yield of soybean plant under drought condition. materials and methods location the pot experiment was conducted under semi-controlled environment in poly house condition in the department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), bangladesh during 2020-2021. the experimental site was situated in a subtropical climatic zone of madhupur tract (aez 28) (24.09° n latitude and 90.26° e longitude) above 8.4 m above the mean sea level and about 40 km north of dhaka. plastic pots (30 cm length and 24 cm diameter) were used in the experiment which was filled with soil, holds about 28% moisture at field capacity (fc). soil used in the plastic pots was clay loam with 40.51% sand, 28.78% silt and 30.71% clay having ph of 6.93. the soil organic carbon, available p, exchangeable k were 0.61%, 0.8 mg 100g-1 soil and 0.79 cmolc kg-1 dry soil, respectively. the soil was mixed with cowdung at 1:0.25 ratio and dried well. then each pot was filled with 11 kg of that soil mixture. plant materials and preparation of nano solution soybean variety bu soybean-1 was used in this experiment. this high yielding variety was released by the bangabandhu sheikh mujibur rahman agricultural university. for the preparation of nano zinc solution, zinc nano powder of having 50-100 nm particle size and 1525 m2/g have been used and zinc was 79.1-81.5% (complexometric titration) (sigma-aldrich, 2016). to prepare 100 ppm nano zno solution, 100 mg of this powder was added to 1 l of distilled water and similarly, 200 ppm nano zno solution was prepared by adding 200 mg of that zno powder into 1 l of distilled water. both of the solutions were heated at 60°c temperature for 16 hours on magnetic stirrer with hot plate. after that, sonication bath was given to both solutions with vibration to mix all the particles into the water homogenously, so that the solution can foliar application of nanoparticles on growth, yield and drought tolerance of soybean 75 penetrate through the plant leaves effortlessly during the application (sandhya et al., 2021). then those solutions were stored in a plastic bottle at room temperature. the required amount of solution was inserted into the hand sprayer during the application of the solution into the plant. treatments and intercultural operation ten healthy seeds were sown maintaining uniform spacing in each pot. after sowing, minimal irrigation was applied by using a beaker to maintain uniform germination. thinning was done during the appearance of first two leaf stage and kept three uniform and apparently healthy plants in each pot. uniform application of 0.32 g urea, 0.933 g tsp and 0.64 g mop was given into each pot corresponding to 80-205-128 kg urea, triple super phosphate and muriate of potash ha-1, respectively (frg, 2018). after trifoliate stage the pots were investigated regularly to identify the moisture level of soil by using portable digital moisture meter (pogo soil sensor ii, stevens, usa) and 1 l of water was added on a regular basis to maintain the field capacity to 80% in nine pots of well-watered (control) plants and 500 ml was added to the rest of the each pot which were kept in water stressed condition by having 40% field capacity (drought) throughout the growing season. the experiment consisted of two factors. factor a: i. well water (control), ii. drought, factor b: 3 doses of nano zno. the control and drought treated plants leaves were sprayed with water (0 ppm nano zno), 100 ppm nano zno solution and 200 ppm nano zno solutions through a hand sprayer after 15 days beginning of drought stress. the experiment was laid out in completely randomized design (crd) with three replications. growth and yield parameters morphological growth related parameters, such as height of plants, leaf, stem fresh weight and total dry weight were observed after 15 days of spraying (at flowering stage). at the physiological maturity stage, seed yield plant-1, number of pods plant-1, number of seed pod-1, and 100-seed weight were also recorded. statistical analysis the crop stat statistical software version 7.2 has been used to analyze the recorded data. mean values of all treatments were compared using least significance difference (lsd) test at 5% level of significance results and discussion plant height plant height is one of the most important morphological traits to determine the growth and development of the plant. the scarcity of water affected the increment of plant height remarkably (figure 1). the height of soybean plants had been decreased by 15.85% under drought relative to the control condition. in control condition, plant height had reached maximum to 32.07 cm after the application of 200 ppm of nano zno fertilizer and the lowest was 26.95 cm in untreated plants. in drought condition the highest height was found into the plants which were treated with 200 ppm nano fertilizer. among all of the treatments, the untreated plants remained to the rock-bottom level with only 22.68 cm height under drought. more specifically, at 15 days after the application of 100 and 200 ppm of nano zno fertilizers, the height of the bu soybean-1 had been increased by 17.17 and 18.1%, respectively in control condition compared to the untreated plants. simultaneously, in drought condition, plant height had been increased significantly by 12.87 and 76 dola et al. 21.7%, due to the application of 100 and 200 ppm of nano zno fertilizers, respectively. similar result was reported by gholinezhad (2017), that application of nano fertilizer increased plant height by 20% in comparing to the control (no fertilizer) condition. according to dola et al. (2022), application of 200 ppm nano iron fertilizer enhanced the plant height by 21.24% in drought condition compared to the untreated plants. due to having small and high solubility compound, nano fertilizer absorbed quickly by plants and solved food shortages plants and increased plant growth (rasht, 2013). according to linh et al. (2020), height of nano particle treated plants reached approximately 50 cm, while 40 cm in the untreated control plants under drought conditions. fig. 1. effect of zinc fertilizer on plant height of soybean after 15 days of spraying. bars indicate (±se). znn0, znn1, znn2 = 0, 100 and 200 ppm nano fertilizer, respectively. fresh weight drought is one of the most alarming abiotic stress for soybean plants which affects almost all of the morphological traits of the plants severely. the water stressed condition affects fresh weight of leaf, stem and finally the total fresh weight of soybean plants adversely. due to drought condition, fresh weight of soybean leaves had been attenuated drastically by 28.36% compared to the control condition (table 1). but after the application of nano fertilizers, the amount of loss had been minimized. in control condition, the maximum leaf fresh weight was recorded 14.28 g after 200 ppm nano zinc solution spray, whereas, 11.32 g was the lowest. considering the water deficit condition, maximum fresh weight of leaves was 9.92 g found into 200 ppm nano zinc solution treated plants. among all of the experimental plants, untreated drought stressed plants were bearing the lowest sized leaves which were only 8.11 g. in drought stressed condition, fresh weight of soybean leaves increased by 13.07 and 22.32% at 15 days later of the foliar application of 100 and 200 ppm nano zno solution, respectively relative to untreated plants. in control condition, 100 and 200 ppm nano zinc fertilizers incremented the leaf fresh weight by 19.43 and 26.15%, respectively compared to the untreated plants. stem weight is also an impactful parameter which influences the total weight of a plant. the drought condition in vegetative stage of soybean plants deteriorated the fresh weight of stem by 37.24% compared to the control condition (table 1). the highest stem fresh weight of soybean was encountered as 6.08 g into the plants treated with 200 ppm nano zinc fertilizer and the minimum of 4.35 g into the untreated plants in control condition. in drought condition, the maximum fresh weight of soybean stem was 4.63 g achieved by the application of 200 ppm nano fertilizer and the lowest bc d a c a b 0 5 10 15 20 25 30 35 control (80% of fc) drought (40% of fc) p la n t h e ig h t (c m .) water regimes znn0 znn1 znn2 foliar application of nanoparticles on growth, yield and drought tolerance of soybean 77 stem fresh weight only 2.73 g into the untreated plants. in control condition, stem fresh weight improved by 17.47 and 39.77% at 15 days after 100 and 200 ppm nano zno fertilizers treatments application, respectively related to untreated plants. moreover, in drought condition, 100 and 200 ppm nano zinc solution accelerate the fresh weight of soybean plants exponentially by 28.94 and 69.6%, respectively compared to the plants remained untreated. evaluating all of the data mentioned above, it could be manifested that the solution of nano zinc particles also had a great impact on the total fresh weight of soybean plants. certainly, the water deficit condition into the soybean plants curtailed the total fresh weight by 30.82% compared to the plants grown in control condition (table 1). in control condition, the highest total fresh weight of soybean was found 20.36 g after the exogenous use of 200 ppm nano zno fertilizer and the minimum value was 15.67 g observed in totally untreated plants. in drought condition, the untreated plants had the lowest total fresh weight of 10.84 g only. but 15 days after the application of 200 ppm nano zinc particles in drought condition increased the total fresh weight of soybean to 14.55 g. in control condition, 100 and 200 ppm solution of nano zno improved the total fresh weight of soybean plants by 18.89 and 29.93%, respectively compared to the untreated plants. furthermore, the acceleration of the total fresh weight of soybean plants was 17.01 and 34.23% with the foliar application of 100 ppm and 200 ppm nano zinc fertilizer, respectively in drought condition relative to the untreated plants. this phenomenon should be considered as a noticeable increment in morphological growth of soybean plants. similar result was reported in green gram (vigna radiata l.) by raju et al. (2016). according to gülser et al. (2019), the highest stem fresh weight was found after the application of 30 mg kg-1 iron. linh et al. (2020) also found that treatment of nano particles improved the shoot development in both well-watered and drought-stressed plants at the vegetative stage. liu and lal (2014) have also claimed the similar result that using nano solutions increased the growth rate of soybeans by 33%. according to askary et al. (2017), the application of fe2o3 nanoparticles had significantly increased plant growth than the untreated plants. table 1. effect of zinc nano fertilizer on leaf fresh weight, stem fresh weight and total fresh weight of soybean after 15 days of spraying nano zinc (ppm) leaf fresh weight (g plant-1) stem fresh weight (g plant-1) total fresh weight (g plant-1) control drought control drought control drought 0 11.32b 8.11c 4.35ab 2.73b 15.67b 10.84c 100 13.52ab 9.17bc 5.11ab 3.52b 18.63ab 12.69bc 200 14.28a 9.92bc 6.08a 4.63ab 20.36a 14.55b lsd(0.05) 1.72 2.28 1.81 cv (%) 11.6 23.2 11.5 means followed by diverse letters differ significantly by lsd at p < 0.05 dry weight the harmful effect of water stressed condition in soybean plants declined the dry weight of different plant parts in vegetative stage remarkably. due to the drought condition, dry weight of soybean leaves had been decreased by 55.37% in vegetative stage of plants compared to the control condition (table 2). at 15 days after the foliar application of 200 ppm nano zinc fertilizer in control condition, the highest dry weight of soybean leaves was estimated as 2.48 g, whereas in this similar condition and stage, the untreated plants provided only 1.77 g dry weight of leaves in soybean plants. in drought condition, maximum 1.47 g of leaf dry weight was observed due to the foliar application of 200 ppm nano zinc solution. evidently, among all of 78 dola et al. the treatments and conditions, the lowest leaf dry weight (0.79 g) was found into the untreated drought affected plants. after the application of 100 and 200 ppm nano zno solution in control condition, dry weight of soybean leaves increased by 18.64 and 40.11%, respectively compared to the untreated plants. in drought condition, a significant increment of leaf dry weight by 37.97 and 86.08%, had been observed after the application of 100 and 200 ppm solution of nano zinc particles, respectively relative to the untreated plants. stem dry weight of soybean plants at vegetative stage had been deteriorated by 70.83% due to the hazardous effect of drought condition compared to the control condition (table 2). the highest amount of stem dry weight of soybean was 2.12 g, achieved by the foliar application of 200 ppm nano zinc solution in control condition. but due to avoiding all of the doses of nano zinc solution, stem dry weight of soybean plants was measured as only 1.44 g in control condition. conversely, the lowest stem dry weight of soybean plants was only 0.42 g found into the untreated plants grown in drought condition. in vegetative stage of soybean plants, 100 and 200 ppm nano zinc solution enhanced stem dry weight by 29.86 and 45.83%, respectively in control condition relative to the untreated plants. in drought condition, application of 100 and 200 ppm of nano zno fertilizer incremented stem dry weight by 35.71 and 59.52%, respectively compared to the untreated plants. table 2. effect of zinc nano fertilizer on leaf dry weight, stem dry weight and total dry weight of soybean after 15 days of spraying nano zinc (ppm) leaf dry weight (g plant-1) stem dry weight (g plant-1) total dry weight (g plant-1) control drought control drought control drought 0 1.77b 0.79c 1.44b 0.42c 3.22c 1.21f 100 2.1ab 1.1c 1.87a 0.57c 3.97b 1.66e 200 2.48a 1.47bc 2.12a 0.67c 4.60a 2.13d lsd(0.05) 0.41 0.27 0.40 cv (%) 14.1 13.0 8.1 means followed by diverse letters differ significantly by lsd at p < 0.05. after the analysis of the above mentioned data, it was evident that the nano zinc particles could outperform to improve the dry weight of soybean plants in vegetative stage. due to the harmful effect of drought, the total dry weight of soybean plants had dropped down by 62.42% relative to the control condition (table 2). the maximum total dry weight of soybean had been observed as 4.60 g into the plants treated with 200 ppm nano zno fertilizer in control condition. in control condition, only 3.22 g of total dry weight had been also noticed into the untreated plants. in drought condition, the highest amount of total dry weight of soybean plants was 2.13 g, attained after the application of 200 ppm nano zinc whereas, the lowest amount was only 1.21 g, obtained from the untreated plants suffering from drought condition. after the foliar application of 100 and 200 ppm of nano zno fertilizer in control condition, the total dry weight of soybean plants increased by 23.29 and 42.86%, respectively compared to untreated plants. in drought condition, the total dry weight had been accelerated sharply by 37.19 and 76.03% with the application of 100 and 200 ppm of nano zno fertilizer, respectively. chakralhoseini et al. (2002) found that iron at low concentration of 2.5 mg kg-1 in soil increased dry matter weight of soybean. sheykhbaglou et al. (2010) reported that application of nano-iron oxide at the concentration of 750 ppm caused an increase in dry pod weight and dry weight of leaf plus pod in soybean. according to vaghar et al. (2020), in early grain filling stage, the combined fe and zn foliar application increased the total dry matter content by 20.9%. foliar application of nanoparticles on growth, yield and drought tolerance of soybean 79 yield and yield contributing characters the number of pods is considered as one of most important yield components of soybean plants. due to the drought condition, the number of pods of soybean plants decreased by 25.36% compared to the control condition (table 3). the highest number of pods plant-1 was 61.86 found into 200 ppm nano zno fertilizer treated plants in control condition. in control condition, 54.11 pods plant-1 on average also found due to the lack of nano iron solution. the lowest number of pods were counted as 40.39 pods plant-1 into drought condition when none of the treatments were applied. in drought condition, about 52.94 pods plant-1 was also found after the application of 200 ppm of nano zno fertilizer. this foliar application of 100 and 200 ppm nano zno fertilizer in control condition increased the number of pods plant-1 by 8.43 and 14.32%, respectively in relation to the untreated plants. in drought condition, the application of 100 and 200 ppm nano zno fertilizer raised the average number of pods plant-1 by 47.78 and 52.94%, respectively compared to the untreated plants. the number of seeds pod-1 is directly related with the final yield content of soybean plants. about 27.62% less number of seeds pod-1 was found into a drought affected soybean plants compared to the control condition (table 3). the highest average number of seeds pod-1 (2.66) was recorded into 200 ppm nano zno fertilizer treated plants in control condition. in control condition, an average number of seeds pod-1 (2.10) when the plants remained untreated. the lowest number of seeds pod-1 was only 1.82 encountered into the untreated plants in drought condition. the foliar application of 200 ppm of nano iron solution increased seeds pod-1 to 1.86 seeds in drought condition. the application of 100 and 200 nano zno fertilizer increased the number of seeds pod-1 by 17.62 and 26.66%, respectively compared to the untreated plant. also in drought condition, the application of 100 and 200 ppm nano zno fertilizer improved the average number of seeds pod-1 in soybean plants by 13.16 and 19.74%, respectively relative to the untreated plants. table 3. effect of zinc nano fertilizer on number of pods plant-1, number of seeds pod-1, 100 seeds weight and seed yield of soybean nano zinc (ppm) number of pods plant-1 number of seeds pod-1 100seeds weight (g) seed yield (g plant-1) control drought control drought control drought control drought 0 54.11b 40.39d 2.1b 1.52c 9.94ab 6.41c 11.63c 4.74f 100 58.67ab 47.78c 2.47ab 1.72bc 10.1a 7.52bc 13.15b 6.09e 200 61.86a 52.94bc 2.66a 1.82bc 10.49a 8.76b 14.37a 7.75d lsd(0.05) 5.89 0.50 1.26 1.18 cv (%) 6.3 13.8 8.0 6.9 means followed by diverse letters differ significantly by lsd at p < 0.05. the obvious negative effect of drought condition also affects the 100-seeds weight noticeably. due to the drought condition in soybean plants, the 100-seeds weight of soybean had been declined by 35.51% compared to control condition (table 3). the maximum 100-seeds weight of soybean plants (10.49 g) was estimated into the 200 ppm of nano zno fertilizer treated plants in control condition. moreover, into this control level, 9.94 g of 100-seeds weight was also measured when the plants remained totally untreated. the lowest value of 100-seeds weight of soybean plant was only 6.41 g found into the untreated plants suffering from drought. whereas, the 100-seeds weight of 8.76 g was also observed in drought condition when the plants treated with 200 ppm nano zno fertilizer. the application of 100 and 200 ppm nano zno fertilizer incremented the 100-seeds weight of soybean plants in control condition by 1.51 and 5.53%, respectively compared to the untreated plants. the soybean under drought 80 dola et al. condition also manifested an increase of 100-seeds weight by 17.32 and 36.66%, due to the application of 100 and 200 ppm nano zno fertilizer, respectively compared to the untreated plants. the yield is one of the most vital components of any crop which defines the productivity of that crop. the average yield of soybean had been declined due to the adverse effect of drought condition by 59.24% compared to the control condition (table 3). the highest seed yield was 14.37 g plant-1 in 200 ppm of nano zno fertilizer treated plants in control condition. in control condition, only 11.63 g plant-1 yield was also calculated into the untreated plants. the lowest amount of yield was only 4.74 g plant-1 estimated into the drought affected plants which remained untreated. an increased yield of 7.75 g plant-1 was also found in drought condition, after the application of 200 ppm nano zno fertilizer. the application of 100 and 200 ppm nano zno fertilizer in control condition increased the yield by 13.07 and 23.56%, respectively compared to the untreated plants. in drought condition, the soybean plants treated with 100 and 200 ppm nano zno fertilizer depicted a raise by 26.79 and 63.50% of yield, respectively compared to the untreated plants. similar result was also found by vaghar et al. (2020) that under stressed conditions in the flowering, pod formation and seed filling stage, fe and zn nanochelates increased the number of grains plant-1, average seed yield of soybean by 43.8% and, reached the production rate of 2901.93 kg ha-1 more than other treatments. zn and mn foliar application increased the number of pods plant-1 by 23.2% compared with control (vaghar et al., 2020). in irrigation withheld conditions in pod formation, and seed filling stages, the treatment of zn and mn increased the number of pods plant-1 by 25.2%, and 20.6%, respectively compared to the control treatment. zn and mn treatment raised the 100-seed weight, where this increase was 16.5% higher than in the control. under stress conditions, it was 22% (vaghar et al., 2020). conclusion the growth, dry matter accumulation, and yield of soybean have been negatively impacted by the water deficiency condition. however, the negative effects of drought stress reduced when zno nanoparticles were applied as foliar to plants. the foliar application of 200 ppm zno nano particles performed the best to rectify the negative effect of drought and increases the plant characters (plant height, fresh and dry weight of leaf, stem and whole plant) and yield contributing traits (seed yield, 100-seed weight, number of seeds pod-1, number of pods plant-1) of soybean. according to these findings, it can be suggested that the foliar application of zno can amend the adverse effect of drought condition and uphold the yield of soybean. references askary, m., m.r. amirjani and t. saberi. 2017. comparison of the effects of nano-iron fertilizer with iron-chelate on growth parameters and some biochemical properties of catharanthus roseus. j. plant nut: 40(7): 974-982. chakralhoseini, m. r., a. ronaghi, m. mafton and n.a. karimian. 2002. soybean response to application of iron and phosphorus in a calcareous soil. sci. technol. j. agric. natur. res. 6(4): 91-101. crossa, j. 1990. statistical analyses of multilocation trials. adv. agron. academic press. 44: 55-85. cunningham, f.j., n.s. goh, g.s. demirer, j.l. matos and m.p. landry. 2018. nanoparticlemediated delivery towards advancing plant genetic engineering. trends biotechnol. 36(9): 882-897. foliar application of nanoparticles on growth, yield and drought tolerance of soybean 81 davar, z.f., a. roozbahani and a. hosnamidi. 2014. evaluation the effect of water stress and foliar application of fe nanoparticles on yield, yield components and oil percentage of safflower (carthamus tinctorious l.). inter. j. adv. biol. biomed. res. 2(4): 11502014. derosa, m.c., c. monreal, m. schnitzer, r. walsh and y. sultan. 2010. nanotechnology in fertilizers. nat. nanotec. 5(2): 91. dola, d.b., m.a. mannan, u. sarker, m.a.a. mamun, t. islam, s. ercisli, m.h. saleem, b. ali, o.l. pop and r.a. marc. 2022. nano-iron oxide accelerates growth, yield, and quality of glycine max seed in water deficits. front. plant sci. 13: 992535. engels, c., f.a. rodrigues, a.o. ferreira, t.m. inagaki and a.l. nepomuceno. 2017. drought effects on soybean cultivation-a review. ann. res. rev. biol. 16(1): 1-13. frg (fertilizer recommendation guide). 2018. fertilizer recommendation guide. bangladesh agricultural research council, dhaka, bangladesh 1215. gholinezhad, e. 2017. effect of drought stress and fe nano-fertilizer on seed yield, morphological traits, essential oil percentage and yield of dill (anethum graveolens l.). j. essent. oil bear. plants. 20(4): 1006-1017. gülser, f., h.i. yavuz, t.h. gökkaya and m. sedef. 2019. effects of iron sources and doses on plant growth criteria in soybean seedlings. eurasian j. soil sci. 8(4): 298-303. indexmundi. 2021. bangladesh soybean oilseed production by year. retrieved from https://www.indexmundi.com/agriculture/?country=bd&commodity=soybeanoilseed&graph=production kashyap, p.l., s. kumar and a.k. srivastava. 2017. nano diagnostics for plant pathogens. environ. chem. lett. 15(1): 7-13. kashyap, p.l., p. rai, s. sharma, h. chakdar, s. kumar, k. pandiyan, and a.k. srivastava. 2016. nanotechnology for the detection and diagnosis of plant pathogens. in nanoscience in food and agriculture 2 (pp. 253-276). springer, cham. linh, t.m., n.c. mai, p.t. hoe, l.q. lien, n.k. ban, l.t.t. hien, n.h. chau and n.t. van. 2020. metal-based nanoparticles enhance drought tolerance in soybean. journal of nanomaterials. 2020, article id 4056563, 13 pages, 2020. https://doi.org/10.1155/2020/4056563 liu, r. and r. lal. 2014. synthetic apatite nanoparticles as a phosphorus fertilizer for soybean (glycine max). sci. rep. 4(1): 1-6. mir, r.r., m. zaman-allah, n. sreenivasulu, r. trethowan and r.k. varshney. 2012. integrated genomics, physiology and breeding approaches for improving drought tolerance in crops. theor. appl. genet. 125(4): 625-645. mitra, j. 2001. genetics and genetic improvement of drought resistance in crop plants. curr. sci. 80(6): 758-763. movahhedy-dehnavy, m., s.a.m. modarres-sanavy and a. mokhtassi-bidgoli. 2009. foliar application of zinc and manganese improves seed yield and quality of safflower (carthamus tinctorius l.) grown under water deficit stress. ind. crops prod. 30(1): 82-92. nagesh, a.k.b. 2019. foliar application of nanofertilizers in agricultural crops—a review. j. farm. sci. 32: 239–249. raju, d., u.j. mehta, and s.r. beedu. 2016. biogenic green synthesis of monodispersed gum kondagogu (cochlospermum gossypium) iron nanocomposite material and its application in germination and growth of mungbean (vigna radiata) as a plant model. iet nanobiotechnol. 10(3): 141-146. 82 dola et al. rasht, i. 2013. effect of application of iron fertilizers in two methods' foliar and soil application on growth characteristics of spathyphyllum illusion. eur. j. exp. biol. 3(1): 232-240. salehi-lisar, s.y and h. bakhshayeshan-agdam. 2016. drought stress in plants: causes, consequences, and tolerance. in: drought stress tolerance in plants, 1: pp.1-16. springer, cham. sandhya, m., d. ramasamy, k. sudhakar, k. kadirgama, w.s.w. harun. 2021. ultrasonication an intensifying tool for preparation of stable nanofluids and study the time influence on distinct properties of graphene nanofluids–a systematic overview. ultrason. sonochem. 73: 105479. seleiman, m.f., a.f. almutairi, m. alotaibi, a. shami, b.a, alhammad and m.l. battaglia. 2021. nano-fertilization as an emerging fertilization technique: why can modern agriculture benefit from its use? plants. 10(1): 2. sharifi, s.r. and s. khoramdel. 2016. effects of nano-zinc oxide and seed inoculation by plant growth promoting rhizobacteria (pgpr) on yield, yield components and grain filling period of soybean (glycine max l.). iranian j. field crops res. 13(4): 738-753. sheykhbaglou, r., m. sedghi, m.t. shishevan and r.s. sharifi. 2010. effects of nano-iron oxide particles on agronomic traits of soybean. not. sci. biol. 2(2): 112-113. sigma-aldrich. 2016. certificate of analysis. iron (ii, iii) oxide-nanopowder, 50-100 nm particle size (sem), 97% trace metal basis. 3050 spruce street, saint louis, mo 63103, usa. sinclair, t.r. 2011. challenges in breeding for yield increase for drought. trends plant sci. 16(6): 289-293. singh, m.d. and b.a. kumar. 2017. bio efficacy of nano zinc sulphide (zns) on growth and yield of sunflower (helianthus annuus l.) and nutrient status in the soil. int. j. agric. sci. 9(6): 37953798. tarafdar, j.c., r. raliya, h. mahawar and i. rathore. 2014. development of zinc nanofertilizer to enhance crop production in pearl millet (pennisetum americanum). agric. res. 3(3): 257262. usda. 2019. bangladesh: oilseeds and products annual. retrieved from https://www.fas.usda.gov/data/bangladesh-oilseeds-and-products-annual-1. vaghar, m.s., s. sayfzadeh, h.r. zakerin, s. kobraee and s.a. valadabadi. 2020. foliar application of iron, zinc, and manganese nano-chelates improves physiological indicators and soybean yield under water deficit stress. j. plant nut. 43(18): 2740-2756. bangladesh agron. j. 2021, 24(2): 73-81 effects of planting dates on growth, yield and quality of newly released sugarcane varieties m.a.t. sohel*, m.s. hossain, n. islam, m. kamruzaman, f.h. shantaand r.r. rajib bangladesh sugarcrop research institute, ishurdi, pabna, bangladesh corresponding e-mail: atsohel@yahoo.com (received: 31july 2021, accepted: 16september 2021) key words: sugarcane, planting date, yield abstract the experiment was conducted at farmer’s field of kapasia, gazipur during november, 2011 to march, 2013under the aez 28 (modhupur tract).the experiment was carried out to find the effects of varieties and planting dates on growth, yield and quality of sugarcane. two varieties (viz; isd 38 and isd 39) and five planting datesfrommid-november to mid-marchwere laid out in a factorial randomized complete block (rcb) design with three replications. among the varieties, there was no significant difference; however isd 38 performed better than isd 39 in all aspect of yield contributing characters. growth characters viz., tillers and millable cane stalks were significantly influenced by different planting dates. the highest germination (72.17%), tiller (111.03  103 ha-1), millable cane (91.12  103 ha-1), pol % cane (14.91%)and cane yield (75.47 t ha-1) were obtained from midnovember planting and gradually decreased with the advancement of planting times where all the lowest values were recorded from mid-march planting. interaction between variety and planting date, mid-november planting with isd 38 produced the highest germination (73.67%), tiller (115.39  103 ha-1), millable cane (98.16  103 ha-1), pol % cane (14.95%) and cane yield (93.64 t ha-1). the overall results revealed that variety isd 38 in mid-november planting is optimum for sugarcane production under the modhupur tract soils of bangladesh. introduction the total area and production of sugarcane in bangladesh are gradually reducing. at present, the area under sugarcane is about 80.97 thousand hectares covering both mill and non-mill zones with an annual production of about 3142 thousand tons (bbs, 2019). although bsri released high recovery (11-12 %) varieties but in the mills it stands at 6.51-8.4% and for last few years it is almost to 7.0 % (alam et al., 2009). there are number of reasons for lower cane yield and one of those is the planting of low yielding varieties. therefore, it is need of the time to introduce new high yielding varieties with good ratoon ability in the country (chattha and ehsanullah, 2003). mian (2006) reported that variety plays a key role in both increasing and decreasing per unit area sugar yield. the use of inferior quality cane varieties affect sugarcane production negatively as situation prevails today. the solution of low cane yield and sugar recovery problem lies in the planting time of improved cane varieties (chattha et al., 2006).selection of a proper variety to be grown in a particular agro-ecological zone is a primary requisite to explore its yield and sugar recovery potential(james, 2004). viator et al., (2005) stated that planting date is one of the important variables that affects sugarcane stand establishment. hoy et al., (2006) observed that cane weight and maturity of sugarcane are highly associated with planting time that may influence its productivity. due to late planting, the cane http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#viator--r.p.--e.p.-richard-jr.--d.d.-garrison--e.o.-dufrene-jr.-and-t.l.-tew.-2005 http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#hoy--j.w.--a.e.-arceneaux-and-c.f.-savario.-2006 74 sohel et al. germination and tiller population become lowered consequently resulted in lesser millable cane stalk production and hence reduced final cane yield (omoto and abaya, 2005). hossain et al. (2011) concluded that growth characters like tillers, millable cane stalks, cane height, girth and unit stalk weight were significantly influenced by different planting dates. the values of all the yield contributing factors and quality parameters were higher in the crops planted in november compared to that planted in february and march. early and late planting had resulted in reduced yield of sugarcane (hoy et al., 2006). a progressive decrease in sucrose content of cane juice was recorded with delay in each planting date. munsif et al. (2018) also observed that higher number of tillers, millable cane production, cane yield and higher sugar recovery was achieved from early planting. jintrawet et al., (2000) found that sugarcane planted during the first week of november gave higher cane yield. the present study was conducted with aim to compare the latest varieties each other and to find out the appropriate planting date for higher yield of sugarcane under the modhupur tract soils of gazipur region. materials and methods the experiment was conducted at grower’s field in kapasia, gazipur during november, 2011 to march, 2013 under the aez 28. the experiment was laid out in a factorial randomized complete block (rcb) design with three replications. each experimental plot had a size of 36.0m2. the treatments were included in the experiment such as factor a: two varieties v1: isd 38 and v2: isd 39 whereas factor b: five planting dates as p1: mid november, 2011, p2: mid december, 2011, p3: mid-january, 2012, p4: mid february, 2012 and p5: mid-march, 2012.. trenches were made by hand spade. setts containing two buds were planted end to end in the main field on 15th of the said months maintaining 100 cm row distance. application of fertilizers was given @ 260, 152, 250, 139 and 6 kg ha-1 as urea, tsp, mp, gypsum and zinc sulphate, respectively (frg, barc, 2005). full doses of tsp, gypsum, zinc sulphate, 1/3rd of urea and mp; regent 3gr @ 22 kg ha-1 for control termite were applied in trenches during the time of plantation. the rest of mp and urea were applied in two equal splits at early tillering stage and late tillering phase of sugarcane. necessary intercultural operations like weeding, mulching, irrigation and pest management were done as and when required. furadan 5g was applied as a preventive measure against borers in two times at 90 and 150 dap @ 40 kg ha-1 for each time. disregarding of the planting dates, all cane were harvested at maturity stage. during the course of the experiment germination, tiller and millable cane production were taken. moreover yield of cane and pol % cane were measured at harvest. economic and statistical analyses on different parameters were done following the standard procedures. the treatment means that were significantly different at 5% levels of significance were separated using the duncan multiple rang test (dmrt). results and discussion germination percentage effects of variety germination percentage was not significant response by varieties (table 1). the variety isd 38 produced the numerically maximum (59.40%) germination percentage than the variety isd 39 (57.67%). thus, in the present finding the variation in germination percentage could be probably attributed to the differences in the genetic makeup of the varieties (worku and chinawong, 2006). effects of planting date planting date exerted a significant effect on germination percentage (table 1). the results indicate that the highest germination percentage (72.17%) was measured from mid-november planting whereas, the lowest germination percentage (52.50%) from mid-march planting. gradual decrease in germination (%) of setts was observed with the delay in planting due to prevailing lowest air temperature. it has http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#omoto--g.-and-g.o.-abayo.-2005.-effect-of-delayed-planti http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#hoy--j.w.--a.e.-arceneaux-and-c.f.-savario.-2006 http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#hoy--j.w.--a.e.-arceneaux-and-c.f.-savario.-2006 http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#jintrawet--a. http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#jintrawet--a. effects of planting dates on growth, yield and quality of newly 75 been observed that speed and percent of germination are greatly reduced when ambient temperature goes below 200c and soil moisture stress exists (miah et al., 2003). interaction effects of variety and planting date interaction effect of variety and planting date on germination percentage was significant (table 2). the maximum germination percentage (73.67%) was observed in mid-november planting with the variety isd 38 but statistically similar in mid-november planting with the variety isd 39 (70.67%) and the lowest (51.33%) was observed in mid-march planting with the variety isd 39 which was statistically followed by the other treatments. tiller production ( 103 ha-1) effects of variety there was no significant response in tiller production of different varieties (table 1). however, the variety isd 38 gave the maximum tiller (94.17  103 ha-1) compared to that of the variety isd 39 (87.58  103 ha-1). effects of planting date planting date had a significant effect on tiller production (table 1). the results revealed that the highest number of tiller (111.03  103 ha-1) was observed in mid-november planting and the lowest (80.48  103 ha-1) from mid-march planting. table 1. germination percentage, tiller production, millable caneand pol% cane as affected by variety and planting date treatments germination percentage tiller production ( 103 ha-1) millable cane ( 103 ha-1) pol %cane variety: isd 38 59.40 94.17 78.76 13.95 isd 39 57.67 87.58 74.13 13.71 lsd at 5% ns ns ns ns planting time: mid-november 72.17 a 111.03 a 91.12 a 14.91 a mid-december 59.83 b 93.56 b 82.44 b 13.97 ab mid-january 54.50bc 88.47 bc 79.15 b 13.73 b mid-february 53.67bc 80.83 c 69.75 c 13.40 b mid-march 52.50 c 80.48 c 59.75 d 13.13 b lsd (0.05) 7.02 10.51 7.44 1.02 cv (%) 9.89 9.54 8.02 6.06 in a column, figures with similar or without letter do not differ significantly and those with dissimilar letter significant at 5% level. ns = not significant the early planted crops produced higher number of tillers but progressively declined with delayed planting. number of tiller consequently affects the yield of sugarcane and is therefore considered to be an important parameter of sugarcane crop (loganandhan et al., 2013). the possible reason for lower tillers in late sowing could be that delay in planting date might result in reducing germination percent due to low temperature which could consequently produce lesser number of tillers. similar results were obtained by omoto and abayo (2005) who also reported that delaying planting date reduces number of tillers. interaction effects of variety and planting date interaction effect of variety and planting date on tiller production was significant (table 2). the maximum tiller production (115.39 103 ha-1) was observed in mid-november planting with the variety http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#loganandhan--n.--gujja--biksham--goud--vinod-and-u.s.-natarajan.-2013 http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#omoto--g.-and-g.o.-abayo.-2005.-effect-of-delayed-planti 76 sohel et al. isd 38 but statistically similar in mid-november planting with the variety isd 39 (106.66  103 ha-1) and the lowest (78.38  103 ha-1) was observed in mid-march planting with the variety isd 39. table 2. interaction effect of variety and planting date on germination percentage, tiller production, millable cane and pol% cane treatments germination percentage tiller production ( 103 ha-1) millable cane ( 103 ha-1) pol % cane variety x planting time isd 38 mid-november 73.67 a 115.39 a 98.16 a 14.95 a mid-december 60.67 b 98.70 bc 84.05 b 14.20 abc mid-january 54.67 b 94.44 bcd 80.61 bc 13.73 abc mid-february 54.33 b 82.58 de 70.33 cde 13.63 abc mid-march 53.67 b 79.72 de 60.61 ef 13.33 c isd 39 mid-november 70.67 a 106.66 ab 84.08 b 14.87 ab mid-december 59.00 b 88.42 cde 80.83 bc 13.83 abc mid-january 54.33 b 82.50 de 77.69 bcd 13.50 bc mid-february 53.00 b 81.95 de 69.16 def 13.47 bc mid-march 51.33 b 78.38 e 58.89 f 12.77 c lsd at 5% 9.93 14.86 10.52 1.44 cv (%) 9.89 9.54 8.02 6.06 in a column, figures with similar or without letter do not differ significantly and those with dissimilar letter significant at 5% level. millable cane ( 103 ha-1)stalks production effects of variety millable cane production was not influenced significantly by varieties (table 1). results indicated that the numerically maximum (78.76  103 ha-1) millable cane produced from the variety isd 38 than the variety isd 39 (74.13  103 ha-1). effects of planting date planting date exhibited a significant effect on millable cane production (table 1). the results stated that the highest millable cane production (91.12 103 ha-1) was found in mid-november planting and the lowest (59.75 103 ha-1) from mid-march planting. the higher millable cane production in early planting might be due to increased photosynthesis resulted by higher leaf area in early planting and thereby increased higher millable cane production. the results are in lined with those of ferdous et al. (2015) which also stated that higher millable cane production was significantly higher in early planting. munsif et al. (2018) also observed that higher millable cane production was achieved from early planting. interaction effects of variety and planting date a significant effect of millable cane production was observed due to interaction between variety and planting date (table 2). mid november planting with the variety isd 38 produced the highest millable cane (98.16 103 ha-1) and the lowest (58.89 103 ha-1) was observed from mid-march planting with the variety isd 39. pol % cane http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#ferdous--h.m.--q.a.-khaliq-and-a.-karim.-2015.-ef http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#ferdous--h.m.--q.a.-khaliq-and-a.-karim.-2015.-ef effects of planting dates on growth, yield and quality of newly 77 effects of variety pol (%) cane was not significantly response by varieties (table 1). the variety isd 38 produced the maximum (13.95%) pol (%) cane than isd 39 (13.71%). effects of planting date planting date had a significant effect on pol (%) cane (table 1). the results indicated that the maximum pol (%) cane (14.91%) was measured from mid-november planting but statistically similar with middecember planting (13.97%) whereas, the lowest pol (%) cane (13.13%) from mid-march planting.sanghera et al. (2016)reported that planting from 15th october to 30th october resulted in low pol (%) cane while 15 november planting showed promising results for enhancement of pol (%) cane. abbas and hossan (2015)observed that pol decreased from 12% to 6.71 % by delay in planting. almodares and darany (2006) also stated that higher pol (%) cane was recorded in early plantings. similar trend was reported by hoque et al. (1994) in bangladesh condition. interaction effects of variety and planting date interaction between variety and planting date on pol (%) cane was significant (table 2). the highest pol (%) cane (14.95%) was observed in mid-november planting with the variety isd 38 but statistically similar in mid-november planting with the variety isd 39 (14.87%) and the lowest (12.77%) in midmarch planting with the variety isd 39 which was statistically followed by the other treatments. cane yield effects of variety the results revealed that sugarcane yield was significantly influenced by variety at harvest (figure 1). between the varieties, higher yield (75.47 t ha-1) was obtained from variety isd 38 than the variety isd 39 (67.84 t ha-1). yield is the contribution of several attributes like number of millable stalk, stalk length and girth of cane. getaneh et al. (2016) observed that significant response represents among different varieties. khan et al. (2003) reported that increase in cane yield might be due to maximum plant height, weight per stool and cane girth. variation among sugarcane varieties in respect of cane yield has also been reported by jamil et al. (2007). fig. 1.sugarcane yield as influenced by variety 0 10 20 30 40 50 60 70 80 90 isd 38 isd 39 y ie ld ( t h a -1 ) variety http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#sanghera--g.s.--r.-kumar--v.-tyagi--k.s.-thind-and-b.-sharma.-2016. http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#abbas--a.-and-s.-hossan http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#almodares--a.-and-s.m. 78 sohel et al. effects of planting date planting date performed significant variation on sugarcane yield at harvest (figure 2). the results indicate that the maximum yield (87.96 t ha-1) was found in mid-november planting, whereas, the lowest yield (51.94 t ha-1) was obtained from mid-march planting. the possible reason for this reduction with delay planting might be due to the reduction in number of tiller, stem diameter, internode length and plant height. the results are in lined with that of jintrawet et al. (2000)who investigated that early planted sugarcane gave higher cane yield. early planting resulted in higher yield of 19.87% as compared to late planting. this result support the findings of hoque et al. (1994) where they reported significant reduction in cane yields from planting beyond november. similar results were observed by hoy et al.(2006). fig. 2.sugarcane yield as influenced by planting date interaction effects of variety and planting date a significant response observed in sugarcane yield among the interaction between variety and planting date at harvest (figure 3). results indicated that the highest yield (93.64 t ha-1) was obtained from midnovember planting with the variety isd 38 whereas, the lowest yield (40.66 t ha-1) was observed in mid-march planting with the variety isd 39. 0 10 20 30 40 50 60 70 80 90 100 mid november mid december mid january mid february mid march y ie ld ( t h a -1 ) planting time http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#jintrawet--a. http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#jintrawet--a. http://researcherslinks.com/current-issues/influence-of-planting-date%20on-yield-and-quality-of-sugarcane-under-the-agro-climatic-conditions-of-mardan/14/1/1706/html#hoy--j.w.--a.e.-arceneaux-and-c.f.-savario.-2006 effects of planting dates on growth, yield and quality of newly 79 fig. 3. sugarcane yield as influenced by interaction effect of variety and planting date conclusion the results indicated that sugarcane variety isd 38 when planting inmid-november resulted in higher cane yield while delayed planting decreased cane yield. thus, variety isd 38 with planting of setts in the month of mid-november is recommended for obtaining higher yield of sugarcane under the modhupur tract soils in bangladesh. references abbas, a. and s. hossan. 2015. effect of sowing dates and nitrogen levels for ethanol production from sweet sorghum stalks and grains. afr. j. agric. res. 11 (4): 266-275. almodares, a. and s.m.m. darany. 2006. effects of planting date and time of nitrogen application on yield and sugar content of sweet sorghum. j. environ. biol. 27: 601-605. alam, m.m., g.m.m. alam, m.a.s. miah and s. m. k. rahman. 2009. factors affecting sugar recovery of bangladesh sugar industry. pakistan sugar j. 24(1): 14-20. azam, m. and m. khan. 2010. significance of the sugarcane crops with special reference to khyber pakhtunkhwa. sarhad. j. agric. 26(2): 289-295. barc (bangladesh agricultural research council). 2005. fertilizer recommendation guide. published by barc, new airport road, farmgate, dhaka-1215. pp. 97-136. bbs 2019. statistical yearbook of bangladesh. bangladesh bureau of statistics. planning division, ministry of planning. government of the peoples' republic of bangladesh. p. 167. chattha, a.a., m. rafique, m. afzal, f. ahmed and m. bilal. 2006. prospects of sugar industry & sugarcane cultivation in punjab. proceedings of 41th annual convention of pakistan society of sugar technologists held at rawalpindi on august 21-22, 2006. pp. 173-181. chattha, m.u. and e. ehsanullah. 2003. ehsanullah agro-quantitative and qualitative performance of different cultivars and strains of sugarcane (saccharum officinarum l.). pakistan sugar j. 18(06):25. ferdous, h.m., q.a. khaliq and a. karim. 2015. effect of sowing dates on growth and yield of tropical sugarbeet. int. j. agron. agric. res., 1 (7): 53-60. 0 20 40 60 80 100 120 variety x planting date y ie ld ( t h a -1 ) isd 38 x mid november isd 38 x mid deccember isd 38 x mid january isd 38 x mid february isd 38 x mid march isd 39 x mid novemver isd 39 x mid december isd 39 x mid january isd 39 x mid february isd 39 x mid march 80 sohel et al. getaneh, a., f. tadesse, n. ayele and m. bikilla. 2016. agronomic performance evaluation of sugarcane varieties under finchaa sugar estate agro-ecological conditions. afr. j. agric. res. 11(44: 44254433. hoque, m.a.,m.m. uddin and m.n.u. khan. 1994. effect of time and methods of planting on yield and quality of sugarcane. bangladesh j. sugarcane. 16: 146-151. hossain, m. s., m.a.t. sohel, a.k.m.r. islam, m.j. alam and m.k. rahman. 2011. effect of planting date on growth, yield and juice quality of sugarcane. the planter, kuala lumpur, 87 (1028): 200-206. hoy, j.w., a.e. arceneaux and c.f. savario. 2006. effect of date and rate of billetplanting on sugarcane yield. j. am. soc. sugarcane tech. 26(1): 116-124. jintrawet, a., s. laohasiriwong and c. lairuengroeng. 2000. predicting the effect of planting dates on sugarcane performance in thailand. p. 28-29. proceedings of international canegro workshop. august, 4-7. jamil, m., s. afghan, m.a. majid and a. rasool. 2007. ratooning performance of different sugarcane varieties. pakistan sugar j. 22(3):38-47. james, g. 2004. sugarcane (2nd ed.). blackwell science ltd, uk pp. 109-125. kabir, m.l. 1998. effect of planting time and techniques on the yield and yield contributing parameters of sugarcane. m. s. thesis. department of agronomy. bangladesh agricultural university. mymensingh. pp. 21-30. khan, m.a., h.k. keerio, s. junejo, r.n. panhwar, m.a. rajput, y.m. memon and b.r. qazi. 2003. evaluation of new sugarcane genotypes developed through fuzz. correlation of cane yield and yield components. pakistan j. applied sci. 3(4): 270-273. loganandhan, n., gujja, biksham, goud, vinod and u.s. natarajan. 2013. sustainable sugarcane initiative (ssi): a methodology of more with less. sugar technol. 15(1): 98-102. https://doi.org/10.1007/s12355-012-0180-y miah, m.a.s.,m.a.hossain, m.f. hasan, s.aliand m.r.alam. 2003. sugarcane germination under subtropical climate in bangladesh. indian sugar. 52(12): 991-1001. mian, a.m. 2006. sugarcane variety composition in pakistan. proceedings of seminars on agriculture. organized by pakistan society of sugar technologists held at faisalabad on 19th june 2006. pp.107-121. mohamed, b.d. and a.b.a. el-taib. 2007. evaluation of some spring planted sugarcane genotypes under different growing seasons: 1-quality traits performance. assiut. j. agric. sci. 38(1):1-15. munsif, f., m. zahid, m.arif, k. ali and i. ahmad. 2018. influence of planting date on yield and quality of sugarcane under the agro-climatic conditions of mardan. sarhad j. agric. 34(3): 649-655. nazir, a., g.a. jariko and m.a. junejo. 2013. factors affecting sugarcane production. pak. j. commer. soc. sci. 7(1): 128-140. omoto, g. and g.o. abayo. 2005. effect of delayed planting of seed cane on sugarcane germination, growth rate and yield. kenya sugar research foundation, technical bulletin no. 2 (may, 2005). rahman, m.s.,s. khatun and m.k. rahman. 2016. sugarcane and sugar industry in bangladesh: an overview. sugar tech. 18 (6). 10.1007/s12355-016-0489-z. soomro, a.f., s. tunio, f.c. oad and i. rajper. 2013. integrated effect of inorganic and organic fertilizer on yield and quality of sugarcane. pak. j. bot. 45(4): 1339-3148. shukla, s.k. and i. singh. 2011. tillering pattern, growth and yield of three promising genotypes of sugarcane under three fertility levels in sub-tropical india. india. j. sugarcane tech. 26(2): 10-13. sanghera, g.s., r. kumar, v. tyagi, k.s. thind and b. sharma. 2016. genetic divergence among elite sugarcane clones (saccharum officinarum l.) based on cane yield and quality traits from northern india. j. exp. biol. agric. sci., 3(2): 184-190. sundara, b. 2000. sugarcane cultivation. vicas publishing house pvt. ltd., new delhi, india. https://doi.org/10.1007/s12355-012-0180-y effects of planting dates on growth, yield and quality of newly 81 viator, r.p., e.p. richard jr., d.d. garrison, e.o. dufrene jr. and t.l. tew. 2005. sugarcane cultivar yield response to planting date. j. amer. soc. sugarcane technol. 25: 78-87. worku, b. and s. chinawong. 2006. agronomic performances and industrial characterstics of sugarcane varieties under finchaa valley conditions, oromiya, east africa. kamphaengsaen acad. j. 4(1): 27-33. bangladesh agron. j. 2022, 25(1): 7-14 fertilizer recommendation for chilli-garlic intercropping system i.s.m. farhad1, e. jahan2, r. sen3, m.m.u. chowdhury4 and s. akhter5 1 & 3soil science division, bari, gazipur, bangladesh 2regional laboratory, srdi, tangail, bangladesh 4on-farm research division, bari, noakhali, bangladesh 5tcrc, bari, gazipur, bangladesh corresponding e-mail: farhadsau@gmail.com (received: 31 january 2022, accepted: 28 february 2022) keywords: intercropping, optimum fertilizer, chilli equivalent yield, bcr abstract an experiment was conducted at central research farm, bari, gazipur and on farm research division, bari, noakhali during rabi season of 2017-18, 2018-19 and 2019-20 to develop a fertilizer recommendation for chilli with garlic intercropping system. six treatment combinations viz. t1= 100% rdcf of chilli + 0% rdcf of garlic, t2= 100% rdcf of chilli +10% rdcf of garlic, t3= 100% rdcf of chilli + 20% rdcf of garlic, t4= 100% rdcf of chilli +30% rdcf of garlic, t5= 100% rdcf of chilli +40% rdcf of garlic and t6= 100% rdcf of chilli +50% rdcf of garlic were tested. the experiment was laid out in randomized complete block design with 3 replications. both chilli and garlic characters significantly influenced by different treatment combinations. the maximum yield of chilli (10.12 and 9.10 t ha-1 at gazipur and noakhali, respectively) and garlic (3.70 and 3.55 t ha-1 at gazipur and noakhali, respectively) were obtained from t6 treatments which were statistically similar with t5 treatment. chilli equivalent yield progressively increased with the increase of inorganic fertilizers. the results showed that t6 provided the highest cey (17.52 and 16.18 t ha-1 at gazipur and noakhali, respectively) followed by t5 (17.47 and 16.14 t ha-1 at gazipur and noakhali, respectively). the highest gross margin (tk. 339755 ha-1 and tk 310198. ha-1at gazipur and noakhali, respectively) as well as bcr (4.50 and 4.32 at gazipur and noakhali, respectively) were obtained from t5 treatment while the lowest net return (tk. 266661 ha1 and tk. 242264 ha-1at gazipur and noakhali, respectively) as well as bcr (3.92 and 3.76 at gazipur and noakhali, respectively) were observed from t1 treatment. though t6 treatment gave higher yield over all the treatments but it showed lower bcr compared to t5 treatment due to higher cost involvement for inorganic fertilizer. introduction in bangladesh, the majority of farmers are practicing monoculture rather than an intercropping system. however, intercropping use nutrients efficiently and gives greater yield stability over monoculture (seran and brintha, 2010). moreover, mixed or intercropping can ensure maximum land utilization of the available resources and compared with each sole crop to increase productivity (launay et al., 2009; mucheru-muna et al., 2010). intercropping is an important tool for getting higher productivity per unit area by intensifying the use of land particularly densely populated countries which has limited per capita land for crop production. chilli is one of the major spices cropin bangladesh which generally grown in char land as a sole crop. farmers of different region especially coastal and char areas grow chilli as a sole or sometimes intercropping with garlic and onion. from the previous research findings of begum et al. (2015), chilli-garlic intercropping system was found very productive and profitable for the char land. moreover, it is a promising practice in coastal saline area as both chilli and garlic can mailto:farhadsau@gmail.com 8 farhad et al. tolerate salinity level up to 3 10 ds m-1 at fruiting stage (amin et al., 2011). however, there is still no recommended fertilizer dose for chilli with garlic intercropping system. to get the maximum return and crop production, fertilizer management is the most logical way to raise total production. so, it is necessary to find out the optimum fertilizer dose for chilli-garlic intercropping system. thus, this experiment was carried at gazipur and noakhali with the objective to develop a fertilizer recommendation for chilli with garlic intercropping system. materials and methods a field experiment was conducted at central research farm, bari, gazipur (aez-28) and on farm research division, bari, noakhali (aez-18) during rabi season of 2017-2018, 2018-19 and 2019-20 to develop a fertilizer recommendation for chilli with garlic intercropping system. the experiment confined with intercropping where chilli was transplanted as main crop and garlic as companion crop. the variety of chilli was bari morich-3 and local in gazipur and noakhali, respectively. the variety of garlic was bari garlic-2 in both the location. before conducting the experiment, initial composite soil samples at a depth of 0-15 cm from the experimental plots were collected and analyzed following standard methods (table 1). table 1. chemical properties of initial soil (0-15 cm depth) of the experimental field at central research farm, bari, joydebpur, gazipur and ofrd, bari, noakhali during rabi season sample ph ec om total n k ca mg p s zn b cu fe mn dsm-1 (%) meq/100 g soil µg g-1 soil a t g az ip u r average 6.1 1.36 0.08 0.18 3.8 2.2 12.0 16 1.6 0.17 4.0 72 8 critical level 0.12 0.12 2.0 0.5 7 10 0.6 0.2 0.2 4.0 1.0 in te rp re ta ti o n s li g h tl y a ci d ic l o w v er y l o w l o w m ed iu m v er y h ig h m ed iu m m ed iu m o p ti m u m l o w v er y h ig h v er y h ig h v er y h ig h a t n o ak h al i average 6.9 0.85 1.23 0.07 0.11 5.0 2.3 9.5 28 1.9 0.49 1.2 17 7.6 critical level 0.12 0.12 2.0 0.5 10 10 0.6 0.2 0.2 4.0 1.0 in te rp re ta ti o n n eu tr al n o n s al in e l o w v er y l o w l o w o p ti m u m v er y h ig h l o w o p ti m u m h ig h o p ti m u m v er y h ig h v er y h ig h v er y h ig h the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 4.0 m  3.0 m. chilli transplantation and garlic cloves dibbling were done on last week of november at gazipur and 2nd week of december at noakhali in all the three consecutive years. one row of garlic was sown in between two rows of chilli. line to line spacing of chilli was 40 cm and chilli to garlic spacing was 20 cm. plant to plant spacing of chilli and garlic was 40 cm and 10 cm, respectively. the experiment was set up with six treatments viz. t1= 100% rdcf of chilli + 0% rdcf of garlic, t2= 100% rdcf of chilli +10% rdcf of garlic, t3= 100% rdcf of chilli + 20% rdcf of garlic, t4= 100% rdcf of chilli +30% rdcf of garlic, t5= 100% rdcf of chilli + 40% rdcf of garlic and t6= 100% rdcf of chilli + 50% rdcf of garlic. recommended fertilizer dose was estimated based on the soil test value. at gazipur, recommended dose of chemical fertilizer (rdcf) for chilli was n99.5 p32.6 k64 s9.5 zn0.2 b0.9 kg ha-1and garlic was n118 p27.5 k60 s28 zn0.5 b2.8 kg ha-1 where as the fertilizer recommendation for chilli-garlic intercropping system 9 recommended doses of chemical fertilizer for chilli and garlic were n104 p52 k89 s1.4kg ha-1 and n127 p44 k83.6 s4b0.7 kg ha-1, respectively at noakhali. the whole amounts of p, s, zn, b and 1/4th of k were applied at the time of final land preparation. remaining k and whole amounts of n were applied in three equal installments at 25, 50 and 75 days after transplantation from 10-12 cm away from the base of the plant which would be beneficial for the growth and yield of garlic. cowdung (5 t ha-1) were applied as a basal in all the plots. all the intercultural operations such as irrigation, weeding, insect control etc. were done as and when necessary. at noakhali, soil salinity level was measured by using electrical conductivity meter adwa (ad 310) at 15 days interval from emergence to maturity stages of the crop in all the three consecutive years and similar trends were observed. salinity level was 1.18 to 10.41 ds m-1, 1.12 to 9.75 ds m-1 and 1.15 to 8.19 ds m-1 in 2017-18, 2018-19 and 2019-20, respectively over the whole growing period. soil salinity gradually increased up to 2nd week of april and then declined due to heavy rainfall at the later stages of the crop growing period. chilli was harvested five times at 15 days interval starting from 3rd week of march, at gazipur and last week of march at noakhali. garlic was harvested in its maturity on 1st week of april and 3rd week of april at gazipur and noakhali, respectively in all the three years. ten plants from each plot were tagged at random to take records on different agronomic parameters of chilli and garlic. data on yield and yield contributing parameters were recorded and statistically analyzed with the help of statistical package statistix 10 (analytical software. tallahassee, fla, usa) and mean separation was tested by duncan’s multiple range test (dmrt) (steel and torrie, 1960). chilli equivalent yield (cey) was calculated after bandyopadhyay (1984): chilli equivalent yield (kg/ha) = yield of garlic(kg/ha ) x price of garlic (tk./kg) price of chilli (tk./kg) methods of chemical analysis soil ph was measured by a combined glass calomel electrode (jackson, 1958). organic carbon determination by wet oxidation method (walkley and black, 1934). total n was determined by modified kjeldahl method. ca and mg were determined by nh4oac extraction method. k, cu, fe, mn and zn were determined by dtp aextraction followed by aas reading. boron was determined by cacl2 extraction method. phosphorus was determined by bray and kurtz method (acid soils) and modified olsen method (neutral + calcareous soils). s was determined by cah4(po4)2. h2o extraction followed by turbidimetric method with bacl2. results and discussion chilli the effect of chemical fertilizers on the yield and yield parameters of chilli are summarized in the tables 2 & 3. chilli yield and yield attributes like plant height, number of branches plant-1, number of fruits plant-1 and average fruit weight plant-1 of chilli were significantly influenced by different nutrient packages. the maximum plant height (65.7 cm and 61.9 cm at gazipur and noakhali, respectively) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of garlic) which was statistically similar with t5 treatment whereas the lowest plant height (59.8 cm and 56.3 cm at gazipur and noakhali, respectively) was obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of garlic). no. of branches plant-1 positively affected by different fertilizer treatment. significantly highest number of branches plant-1 (9.0 and 7.8 at gazipur and noakhali, respectively) was obtained from t6 treatment whereas the lowest number of branches plant-1 (7.3 and 6.1 at gazipur and noakhali, respectively) was recorded in t1 treatment. number of fruits plant-1 progressively increases with the increase of inorganic fertilizers. the maximum number of fruits plant-1 (156.5 and 133.1 at gazipur and 10 farhad et al. noakhali, respectively) was obtained from t6 treatment which was statistically similar with t5 treatment. while the minimum number of fruits plant-1 (127.1 and 101.5 at gazipur and noakhali, respectively) was obtained from t1 treatment. the maximum average fruit weight plant-1 (232.1 g and 207.3 g at gazipur and noakhali, respectively) was obtained from t6 treatment which was statistically similar with t5 . the lowest average fruit weight plant-1 (177.6 g and 154.2 g at gazipur and noakhali, respectively) was recorded in t1 treatment. table 2. yield and yield components of chilli as influenced by different treatment combinations at gazipur during rabi season (pooled data of 3-years) treatments plant height (cm) number of branches plant-1 number of fruits plant-1 average fruit weight plant-1 (g) fruit yield (t ha-1) t1 59.8d 7.3c 127.1d 177.6e 8.13e t2 60.7cd 8.1bc 131.7d 200.1d 8.40d t3 61.3cd 8.4ab 136.6c 207.3c 8.83c t4 62.5bc 8.4ab 142.4b 213.2b 9.19b t5 64.2ab 8.8ab 154.8a 229.5a 10.09a t6 65.7a 9.0a 156.5a 232.1a 10.12a se (±) 1.25 0.98 3.16 2.95 0.19 cv (%) 6.25 5.83 3.87 3.26 7.23 means followed by same letter (s) do not differ significantly at 5% level of significance by duncan’s multiple range test (dmrt) table 3. yield and yield components of chilli as influenced by different treatment combinations at noakhali during rabi season (pooled data of 3-years) treatments plant height (cm) number of branches plant1 number of fruits plant-1 average fruit weight plant-1(g) chilli yield (t ha-1) t1 56.3c 6.1d 101.5e 154.2e 7.26e t2 57.2c 6.5cd 106.3d 162.7d 7.58d t3 58.5bc 6.8bcd 114.8c 175.6c 7.99c t4 60.3ab 7.2abc 123.2b 193.4b 8.41b t5 61.7a 7.6ab 132.6a 205.5a 9.06a t6 61.9a 7.8a 133.1a 207.3a 9.10a se (±) 1.62 0.81 3.54 3.10 0.22 cv (%) 5.46 6.66 4.84 3.52 7.64 means followed by same letter (s) do not differ significantly at 5% level of significanceby duncan’s multiple range test (dmrt) t1= 100% rdcf of chilli + 0% rdcf of garlic, t2= 100% rdcf of chilli +10% rdcf of garlic, t3= 100% rdcf of chilli + 20% rdcf of garlic, t4= 100% rdcf of chilli +30% rdcf of garlic, t5= 100% rdcf of chilli +40% rdcf of garlic and t6= 100% rdcf of chilli +50% rdcf of garlic. yield of chilli progressively increases with the increase of inorganic fertilizers. the maximum yield of chilli (10.12 and 9.10 t ha-1 at gazipur and noakhali, respectively) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of garlic)which was statistically similar with t5 treatment (100% rdcf of chilli +40% rdcf of garlic) and superior to all other treatments.the lowest yield of chilli (8.13 and 7.26 t ha-1 at gazipur and noakhali, respectively) was observed in t1 treatment (100% rdcf of chilli + 0% rdcf of garlic).the result was similar to the findings of jha et al. (2000) and islam (2007) in maize + potato intercropping. garlic the effect of chemical fertilizers on the yield and yield parameters of garlic are summarized in the tables 4 and 5. the results indicated that most of the yield attributes of garlic were significantly fertilizer recommendation for chilli-garlic intercropping system 11 influenced by different treatment combinations except plants m-2. the maximum plant height (52.4 cm and 51.2 cm at gazipur and noakhali, respectively) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of garlic) which was statistically at par with t4 and t5 treatment whereas the lowest plant height (47.3 cm and 46.1 cm at gazipur and noakhali, respectively) from t1 treatment (100% rdcf of chilli + 0% rdcf of garlic). table 4. effect of different treatments on the yield and yield attributes of garlic at gazipur during rabi season (pooled data of 3-years) treatments plant population m-2 (no.) plant height (cm) clove bulb-1 (no.) bulb diameter (cm) individual bulb weight (g) bulb yield (t ha-1) t1 24.4 47.3b 19.4c 3.38d 12.6c 3.09d t2 24.5 48.5b 21.6bc 3.43cd 13.2bc 3.16d t3 24.8 49.1b 21.2bc 3.49bc 14.1abc 3.35c t4 24.7 51.4a 22.8ab 3.54b 14.8ab 3.51b t5 24.7 52.3a 24.1a 3.62a 15.7a 3.69a t6 24.8 52.4a 24.3a 3.64a 15.8a 3.71a se (±) 0.08 1.21 1.13 0.03 0.79 0.05 cv (%) 2.41 5.80 5.81 3.91 5.81 7.12 means followed by same letter (s) do not differ significantly at 5% level of significance by duncan’s multiple range test (dmrt) t1= 100% rdcf of chilli + 0% rdcf of garlic, t2= 100% rdcf of chilli +10% rdcf of garlic, t3= 100% rdcf of chilli + 20% rdcf of garlic, t4= 100% rdcf of chilli +30% rdcf of garlic, t5= 100% rdcf of chilli +40% rdcf of garlic and t6= 100% rdcf of chilli +50% rdcf of garlic. the maximum number of clove bulb-1 (24.3 and 23.8 at gazipur and noakhali, respectively) was obtained from t6 treatment which was statistically similar with t4 and t5 treatment whereas the minimum number of clove bulb-1 (19.4 and 18.9 at gazipur and noakhali, respectively) from t1 treatment (100% rdcf of chilli + 0% rdcf of garlic). both of bulb diameter and individual bulb weight are progressively increases with the increase of fertilizers. the maximum bulb diameter (3.64 cm and 3.60 cm at gazipur and noakhali, respectively) and individual bulb weight (15.8 cm and 15.6 cm at gazipur and noakhali, respectively) were obtained from t6 treatment (100% rdcf of chilli + 50% rdcf of garlic) which was statistically significant with t5 treatment (100% rdcf of chilli + 40% rdcf of garlic). the lowest bulb diameter (3.38 cm and 3.32 cm at gazipur and noakhali, respectively) and individual bulb weight (12.6 cm and 11.9 cm at gazipur and noakhali, respectively) were obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of garlic).yield of garlic progressively increases with the increase of inorganic fertilizers.the maximum bulb yield of garlic (3.71 t ha-1 and 3.55 t ha-1 at gazipur and noakhali, respectively) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of garlic)which was statistically similar with t5 treatment (100% rdcf of chilli +40% rdcf of garlic) and superior to all other treatments.the lowest yield (3.09 and 2.97 t ha-1 at gazipur and noakhali, respectively) was obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of garlic). table 5. effect of different treatments on the yield and yield attributes of garlic at noakhali during rabiseason (pooled data of 3-years) treatments plant population m-2 (no.) plant height (cm) clove bulb-1 (no.) bulb diameter (cm) individual bulb weight (g) bulb yield (t ha-1) t1 24.0 46.1c 18.9c 3.32d 11.9d 2.97e t2 24.1 46.6c 20.8bc 3.41c 12.8cd 3.12d t3 24.1 47.7bc 21.2b 3.49b 13.5bc 3.28c 12 farhad et al. t4 24.3 49.5ab 22.5ab 3.54ab 14.2b 3.37b t5 24.5 51.0a 23.6a 3.59a 15.4a 3.54a t6 24.5 51.2a 23.8a 3.60a 15.6a 3.55a se (±) 0.07 1.16 0.97 0.04 0.45 0.03 cv (%) 2.21 5.91 5.38 3.46 5.54 7.42 means followed by same letter (s) do not differ significantly at 5% level of significance by duncan’s multiple range test (dmrt) t1= 100% rdcf of chilli + 0% rdcf of garlic, t2= 100% rdcf of chilli +10% rdcf of garlic, t3= 100% rdcf of chilli + 20% rdcf of garlic, t4= 100% rdcf of chilli +30% rdcf of garlic, t5= 100% rdcf of chilli +40% rdcf of garlic and t6= 100% rdcf of chilli +50% rdcf of garlic. chilli equivalent yield (cey) chilli equivalent yield was progressively increases with the increase of inorganic fertilizers. the results showed that t6 provided the highest cey (17.52 and 16.18 t ha-1 at gazipur and noakhali, respectively) that was 22.43% and 22.57% higher over t1 at gazipur and noakhali, respectively (figure 1). the treatment t5 also gave higher cey (17.47 and 16.14 t ha-1 at gazipur and noakhali, respectively) followed by t4, t3 and t2. the higher cey was mainly attributed due to additional yield advantage resulted from fertilizer effect in chill-garlicinter cropping. the result was similar to the findings of begum et al. (2016) who observed that there was a trend of increase in potato equivalent yield (pey) with the increase of inorganic fertilizer level and decreased considerably towards lower fertilizer levels. akhteruzzaman et al. (2008) also reported pey increased towards higher fertilizer rates in potato hybrid maize intercropping. cost and return analysis cost and return of chilli with garlic intercropping have been described in the tables 6 & 7. among the treatments, the highest gross margin (tk. 339755ha-1 and tk. 310198 ha-1at gazipur and noakhali, respectively) as well as bcr (4.50 and 4.32 at gazipur and noakhali, respectively) were obtained from t5 treatment (100% rdcf of chilli + 40% rdcf of garlic) whereas the lowest gross margin (tk. 266661 ha-1 and tk. 242264 ha-1at gazipur and noakhali, respectively) as well as bcr (3.92 and 3.76 at gazipur and noakhali, respectively) were observed in t1 treatment (100% rdcf of chilli + 0% rdcf of garlic). though t6 treatment gave higher yield over all the treatmentsbutt it showed lower bcr compared to t5 treatment due to higher cost involvement for inorganic fertilizer. table 6. cost and return analysis of chilli with garlic intercropping system as influenced by different fertilizer treatment combinations at gazipur during rabi season (pooled data of 3-years) treatments yield (t ha-1) chilli equivalent gross total cost gross benefit 14.31 14.72 15.53 16.21 17.47 17.52 13.2 13.82 14.55 15.15 16.14 16.18 0 5 10 15 20 25 0 5 10 15 20 t1 t2 t3 t4 t5 t6 t1 t2 t3 t4 t5 t6 % c e y i n cr e a se o v e r t 1 c h il li e q u iv a le n t y ie ld ( t h a -1 ) treatment fig.1. chilli equivalent yield (cey) and % cey increase over ti in different treatment combinations % chilli equivalent yield increase over t1 chilli equivalent yield gazipur noakhali fertilizer recommendation for chilli-garlic intercropping system 13 chilli garlic yield (t ha-1) return (tk. ha-1) (tk. ha-1) margin (tk. ha-1) cost ratio (bcr) t1 8.13 3.09 14.31 357750 91089 266661 3.92 t2 8.40 3.16 14.72 368000 92566 275434 3.97 t3 8.83 3.35 15.53 388250 94042 294208 4.12 t4 9.19 3.51 16.21 405250 95520 309730 4.24 t5 10.09 3.69 17.47 436750 96995 339755 4.50 t6 10.12 3.71 17.52 438000 98472 339528 4.44 input and output price per kg: urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, zinc sulphate =tk.150, boric acid = tk.220, chilli selling price = tk. 25 and garlic selling price = tk. 50 table 7. cost and return analysis of chilli with garlic intercropping system as influenced by different treatment combinations at noakhali during rabi season (pooled data of 3-years) treatments yield (t ha-1) chilli equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio (bcr) chilli garlic t1 7.26 2.97 13.20 330000 87736 242264 3.76 t2 7.58 3.12 13.82 345500 89028 256472 3.88 t3 7.99 3.28 14.55 363750 90520 273230 4.01 t4 8.41 3.37 15.15 378750 91910 286840 4.12 t5 9.06 3.54 16.14 403500 93302 310198 4.32 t6 9.08 3.55 16.18 404500 94694 309806 4.27 input and output price per kg: urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, zinc sulphate =tk.150, boric acid = tk.220, chilli selling price = tk. 25 and garlic selling price = tk. 50 conclusion from the present study, it may be concluded that treatment package consists of 100% rdcf of chillialong with 40% rdcf of garlic is most profitablefor chilli with garlic intercropping systemin the study area (aez-28 and 18). references akhteruzzaman, m., m.n. islam, b.l. nag and m.t. rahman. 2008. productivity of potato-hybrid maize intercropping under different fertilizer levels. eco-friendly agril. j. 1(5): 300-303. amin, m., m.s. bhuiyan, a.h.m.a. faisal, i.s.m. farhad and m.a. rahaman. 2011. crop adaptation in saline soils of noakhali (i. crop performance). bangladesh agron. j. 14(1 & 2): 43-52. bandyopadhyay, s.k. 1984. nitrogen and water relations in grain sorghum legume intercropping systems. ph. d. dissertation, indian agricultural research institute (iari), new delhi110012, india. begum, s.a., m.s. zaman and a.s.m.m.r. khan. 2015. intercropping of root crops with chilliincharlands of mymensingh. prog. agric. 26: 109-114. 14 farhad et al. begum, a.a., m.s.u. bhuiya, s.m.a. hossain, a. khatun and s.k. das. 2016. effect of fertilizer management on productivity of potato-hybrid maize intercropping system. bangladesh j. agril. res. 41(4): 633-645. islam, m.z. 2007. production potential of maize oriented intercropping as influenced by npk level and row arrangement, ph.d. thesis, dept. agron., bangladesh agril. univ., mymensingh, bangladesh. pp.64-163. jackson, m.l. 1958. soil chemical analysis. prentice hall inc. engle-wood, cliffs, n.y. jha, g., d.p. singh and r.b. thakur. 2000. production potential of maize + potato intercropping as influenced by fertilizer and potato genotypes. indian j. agron. 45(1): 59-63. launay, m., n. brisson, s. satger, h. hauggaard-nielsen, g. corre-hellou, e. kasynova, r. ruske, e.s. jensen and m.j. gooding. 2009. exploring options for managing strategies for pea-barley intercropping using a modeling approach. eur. j. agron. 31: 85-98. mucheru-muna, m., p. pypers, d. mugendi and b. vanlauwe. 2010. a staggered maize-legume intercrop arrangement robustly increases crop yields and economic returns in the highlands of central kenya. field crops res. 115: 132-139. seran, t.h. and i. brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135-145. steel, r.g.d. and j.h. torrie. 1960. principles and procedures of statistics with special reference to the biological sciences. mcgraw hill, new york, pp.187-287. walkley, a. and black, i.a. 1934. an examination of the degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. soil sci. 37: 29-38. microsoft word baj 360c__press bangladesh agron. j. 2020, 23(1): 83-89 impact of integrated weed management on bulb yield of onion m.r. islam1, m. moniruzzaman2, a.j.m. obaidullah1 and a.h.f. fahim3 1s.o., rsrc, bari, magura, 2s.s.o., rsrc, bari, magura, 3s.o., src, bari, bogura corresponding e-mail: rislamriaz@gmail.com (received: 12 may 2020, accepted: 17 july 2020) keywords: onion, bari piaz-1, weed, oxadiazon abstract the experiment was conducted at regional spices research centre, bangladesh agricultural research institute, magura, bangladesh during 2016-2017 and 20172018 to optimize weed management practice for onion bulb production through integrated weed management (iwm). the experiment was laid out in a randomized complete block design with three replications. two different herbicides (oxadiazon and pendimethalin) with different doses in combination with hand weeding (hw) were used as treatments. the total number of treatments were 12 viz. t1=oxadiazon@1.0 l/ha, t2=oxadiazon@1.5 l/ha, t3= oxadiazon@2.0 l/ha, t4= oxadiazon@1.0 l/ha + one hw at 45 dat (days after transplanting), t5= oxadiazon@1.5 l/ha + one hw at 45 dat,t6= oxadiazon@2.0 l/ha + one hw at 45 dat, t7=pendimethalin@1.0 l/ha, t8=pendimethalin@1.5 l/ha, t9= pendimethalin@1.0 l/ha + hw at 45 dat, t10= pendimethalin@1.5 l/ha+ hw at 45 dat, t11= weed free and t12 = weedy check (control). the onion var. bari piaz-1 was used as the test crop. the highest bulb yield (7.63 tha-1 in 2016 & 9.56 t ha-1in 2017) and benefit cost ratio (2.14 in 2016 and 2.46 in 2017) were obtained from t6= oxadiazon@2.0 l/ha + one hand weeding at 45 dat while the lowest bulb yield (4.22 t ha-1in 2016 and 6.28 t ha-1in 2017) was obtained from t12 = weedy check (control), while lowest benefit cost ratio (1.33 in 2016 and 1.74 in 2017) from treatment t11 =weed free. it was concluded that oxadiazon@2.0 l/ha with one hand weeding at 45 days after transplanting performed better for controlling weed and maximizing bulb yield of onion. introduction onion (allium cepa l.) belongs to the family alliaceae, a group that includes bulb crops. it is a condiment crop consumed fresh and dry as a spice and one of the most important vegetable crops in the world (ray and yadav, 2005). onion is a very important and major spice crop in bangladesh. it ranks the first in production among the spices crops cultivated in the country. about 17, 37, 714 matric tones of onion produces from 4, 41, 105 acres of land during 201718 (bbs, 2018). weeds are one of the main plant protection problems in onion fields. they compete with onions for light, nutrients, water, space and also are host plants of several harmful insects and pathogens (dunan et al., 1996, kizilkaya et al., 2001, ghoshel, 2004, qasem, 2006, smith et al., 2008). as in many crops, weeds cause yield reduction in onions owing to slow emergence, low initial growth rate, long vegetative period and low competitive ability of the crop (boyham et al., 2016). onion is poor competitor against weeds due to their slow, vertical growth that fails to shade out weeds (kizilkaya et al., 2001). uncontrolled weed growth caused 84 islam et al. 49 to 86 percent reduction in bulb yield of onion compared with the best herbicidal treatment (james and harlen, 2010). lack of effective and economically viable weed management options for onion production has been reported as a critical constraint affecting farmers' motivation to grow the crop (waiganjo, 2004). the conventional method of weed control i.e. hand weeding and hoeing are vary laborious, time consuming and expensive. weedicides applied at the preemergence stage, significantly controlled the weed population (nargis et al., 2006). panse et al. (2014) reported that post–emergence herbicides kill weeds and keep the hardy weeds under control by arresting their growth through various kinds of deformities in foliage and growing points. on the other hand, patel et al. (2012) was found that the application of pre-emergence herbicide followed by one hand weeding was effective for higher yield of onion. for controlling weed, integrated management through cultural, mechanical and herbicidal methods could be more efficient than single methods because onion is a narrow leafed crop and the herbicides which do not herm onion also may not herm the narrow leafed weed. therefore, the present study was undertaken to optimize weed management practice for onion bulb production through integrated weed management (iwm). materials and methods the experiment was conducted at regional spices research centre, bangladesh agricultural research institute, magura during the year 2016-2017 and 2017-2018. the land was medium high land and clay loam in texture having ph of7.55. the unit plot size was 3.0 m x 1.5 m. the most popular onion variety bari piaz-1 was used with 42 days old seedlings. the crop was transplanted maintaining 15 cm x 10 cm spacing. the experiment was laid out in randomized complete block design with three replications. two different herbicides (oxadiazon and pendimethalin) with different doses in combination with hand weeding (hw) were used as the treatment variables. the total number of treatments were 12 viz. t1= oxadiazon@1.0 l/ha, t2=oxadiazon@1.5 l/ha, t3= oxadiazon@2.0 l/ha, t4 = oxadiazon@1.0 l/ha + one hw at 45 dat (days after transplanting), t5= oxadiazon@1.5 l/ha + hw at 45 dat,t6 = oxadiazon@2.0 l/ha + hw at 45 dat, t7 = pendimethalin@1.0 l/ha, t8 = pendimethalin@1.5 l/ha, t9 = pendimethalin@1.0 l/ha + hw at 45 dat, t10 = pendimethalin@1.5 l/ha + hw at 45 dat, t11 = weed free and t12 = weedy check (control). the fertilizers were applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum at the rate of n120 p54 k75 s20 kg/ha respectively. half of n, k and full dose of p and s were applied at the time of final land preparation and remaining n, k was top dressed into two equal splits at 25 and 50 days after transplanting (dat). four irrigations at 25 dat, 45 dat 70 dat and 90 dat were provided. the crop was harvested 110 days after transplanting. data on plant height (cm), number of leaves per plant, number of weed per m2, neck diameter (cm), length of bulb (cm), diameter of bulb (cm), individual bulb weight (g) and yield (tha-1) were collected. the benefit cost ratio (bcr) was calculated on the basis of prevailing local market price of onion bulbs and cost of inputs. data on weed density (plantm-2), dry matter weight of weeds (gm-2) were recorded from the standing crop by using quadrat of 1m x 1m. weed control efficiency (wce) was calculated by using the following formula used by (das, 2008). �����%� = � − � � �100 where, dmc was dry matter weight of weeds in control plot and dmt was dry matter of weeds in treated plots. the recorded data on yield and other parameters were statistically analyzed by using statitix10 software. the difference between the treatments means were judged by duncan’s multiple range test (dmrt) (gomez and gomez, 1984). impact of integrated weed management on bulb yield of onion 85 results and discussion effect on weed different weed species were found in experimental plots. among them, the prominent weed species were cyperus rotundas, chenopodium album, cynodon dactylon, amaranthus viridis, amaranthus spinosus, physalis heterophylla, echinochloa crusgalli etc. similar types of weed species were also reported in onion field (karim et al., 2014, naresh et al., 2002, panse et al., 2014 and syed and malik, 2001). it was found that the weed density, dry weight of weed and weed control efficiency were varied significantly among the different treatment combinations (table 1). the highest weed density (506.67 no. m-2 in 2016-17 and 596.67 no. m-2 in 201718), dry weight of weed (280.44 g m-2 in 2016-17 and 307.29 g m-2 in 2017-18) and minimum weed control efficiency (0%) was found in weedy check (control) plot. because under this treatment no weeding was done and the plot was allowed to grow weed naturally. in this situation the weed covered the whole plot prior to the onion seedlings establishment and started to take soil nutrients and natural resources such as soil moisture, sunlight etc. the lowest weed density (0 no. m-2), dry weight of weed (0 g m-2) and maximum weed control efficiency (100%) was found in weed free plot. because under this treatment weeding was done immediately the weeds appear on the plot as a result there was no competition between crop and weed for soil nutrient and natural resources. among the herbicidal treatments lowest weed density (26.67 no. m-2 in 2016-17 and 26 no. m-2 in 2017-18), lowest dry weight of weed (35.67 g m-2 in 201617 and 36.46 g m-2 in 2017-18) and maximum weed control efficiency (87.27% in 2016-17 and 88.11% in 2017-18) was found from the application of oxadiazon@2.0 l/ha with one hand weeding at 45 days after transplanting. that means oxadiazon performed better than pendimethalin in onion field for controlling weed. similar results were also reported by uygur et al. (2010). table 1.effect of different weed management treatment on weed treatments weed density (plant m-2) dry weight of weed (g m-2) weed control efficiency (%) 2016-17 2017-18 2016-17 2017-18 2016-17 2017-18 t1 oxadiazon@1.0 l/ha 66.00 bc 54.00 bcd 85.45b 76.66bcd 69.53f 75.12f t2oxadiazon@1.5 l/ha 59.00 bcd 45.00 cd 77.07c 77.76bc 72.50e 74.68f t3oxadiazon@2.0 l/ha 54.00 cde 45.00 cd 70.49d 68.53d 74.85d 77.68d t4 oxadiazon@1.0 l/ha + hw at 45 dat 47.00 de 51.00 cd 63.44ef 74.63bcd 77.37c 75.71ef t5oxadiazon@1.5 l/ha + hw at 45 dat 43.00 e 37.00 cde 70.37d 55.15e 74.90d 82.04c t6 oxadiazon@2.0 l/ha + hw at 45 dat 26.67 f 26.00 de 35.67g 36.46f 87.27b 88.11b t7 pendimethalin@1.0 l/ha 68.00 b 92.00 b 77.44c 54.84e 72.34e 82.13c t8 pendimethalin@1.5 l/ha 64.00 bc 64.00bcd 84.51b 80.06b 69.88f 73.92f t9pendimethalin@1.0 l/ha + hw at 45 dat 50.67de 74.00 bc 68.54de 74.45bcd 75.56d 75.76ef t10 pendimethalin@1.5 l/ha + hw at 45 dat 56.00 bcd 52.00 cd 60.21f 70.63cd 78.51c 76.99de t11 weed free 0 g 0 e 0 h 0 g 100a 100a t12-weedy check (control) 506.67a 596.67a 280.44a 307.29a 0.00 g 0.00 g level of significance ** * ** ** ** ** cv (%) 8.23 24.81 4.47 6.47 1.29 1.49 in a column, means followed by the same letter did not differ significantly by dmrt. hw= hand weeding, dat =days after transplanting, * = 5% level of significance and ** = 1% level of significance. 86 islam et al. effect on growth parameters growth characters of onion as influenced by different treatments revealed significant variations (table 2). the longest plant (52.27 cm in 2016 and 52.36 cm in 2017), higher number of leaves per plant (6.87 in 2016 and 7.47 in 2017) and higher neck diameter (0.94cm in 2016 and 1.27cm in 2017) were recorded from the application of oxadiazon@ 2.0 l/ha with one hand weeding at 45 days after transplanting. the shortest plant (45.00 cm in 2016 and 46.63cm in 2017), lower number of leaves per plant (5.07 in 2016 and 6.3 in 2017) and lowest neck diameter (0.68 cm in 2016 and 0.97cm in 2017) was recorded from weedy check (control) treatment. because due to lacking of optimum environment under weedy condition all the growth parameters reduced and the crop has to survive competing with weeds. similar results were reported by uygur et al. (2010). table 2. effect of different weed management treatments on growth parameters of onion treatments plant height (cm) no. of leaves plant-1 neck diameter (cm) 2016-17 2017-18 2016-17 2017-18 2016-17 2017-18 t1 oxadiazon@1.0 l/ha 49.40 abc 48.58e 6.47 a 6.50f 0.89 a 1.00de t2oxadiazon@1.5 l/ha 50.20 abc 49.63d 6.27 a 6.63de 0.89 a 1.09bc t3oxadiazon@2.0 l/ha 50.07 abc 50.80c 5.60 ab 6.73d 0.79 ab 1.13b t4 oxadiazon@1.0 l/ha + hw at 45 dat 51.40 a 50.62c 6.40 a 7.17b 0.90 a 1.23a t5oxadiazon@1.5 l/ha + hw at 45 dat 49.60 abc 51.57b 6.60 a 7.27b 0.78 ab 1.27a t6 oxadiazon@2.0 l/ha + hw at 45 dat 52.27 c 52.36a 6.87 a 7.47a 0.94 a 1.27a t7 pendimethalin@1.0 l/ha 48.13 c 48.60e 5.80 ab 6.60ef 0.74 ab 1.02cde t8 pendimethalin@1.5 l/ha 48.47 bc 48.69e 6.40 a 6.67de 0.81 ab 1.07cde t9pendimethalin@1.0 l/ha + hw at 45 dat 51.20 ab 50.57c 6.40 a 7.03c 0.79 ab 1.09bc t10 pendimethalin@1.5 l/ha + hw at45 dat 50.80 abc 51.26b 6.07 ab 7.20b 0.86 ab 1.13b t11 weed free 48.20 c 49.47d 6.47 a 6.70 de 0.82 ab 1.11b t12-weedy check (control) 45.00 d 46.63f 5.07 b 6.30 g 0.68 b 0.97e level of significance ** ** * ** ** ** cv (%) 3.52 2.65 10.12 8.64 9.26 13.46 in a column, means followed by the same letter did not differ significantly by dmrt. hw= hand weeding, dat =days after transplanting, * = 5% level of significance and ** = 1% level of significance. effect on yield parameters the yield and yield contributing characters were varied significantly among the different treatment combinations (table 3). the biggest bulb diameter (3.54 cm in 2016 and 4.7 cm in 2017), longest bulb (3.51cm in 2016 and 4.67cm in 2017), heaviest individual bulb (13.20 g in 2016 and 29.72 g in 2017) and highest bulb yield (7.63 tha-1 in 2016 and 9.56 t ha-1 in 2017) was recorded from the application of oxadiazon@2.0 l/ha with one hand weeding at 45 days after transplanting. this is due to the effectiveness of oxadiazon for controlling weed as well as proper timing of hand weeding. so, that the crop gets minimum crop weed competition and impact of integrated weed management on bulb yield of onion 87 optimum growing environment. similar results were recorded from patel et al. (2012) and uygur et al. (2010).the smallest bulb diameter (2.44 cm in 2016 and 2.88 cm in 2017), shortest bulb (3.09 cm in 2016 and 2.96 cm in 2017), lightest individual bulb (8.34g in 2016 and 19.01 g in 2017) and lowest bulb yield (4.22 t ha-1 in 2016 and 6.28 t ha-1 in 2017) were recorded from weedy check (control) treatment. because, under weedy condition the growth parameters of onion such as height and number of leaves were reduced ultimately this lowers the accumulation of photosynthates on the bulb. similar results on variation of onion yield due to different time of planting were also reported by devulkar et al. (2015) and misra et al. (2014). during the year 2017-2018, the bulb yield of onion was higher than the year 2016-2017, this was because of timely showing and transplanting of onion. table 3. effect of different weed management treatments on bulb yield and yield contributing characters of onion treatments bulb diameter (cm) bulb length (cm) single bulb weight (g) bulb yield (t ha-1) 201617 201718 201617 201718 2016-17 201718 201617 201718 t1 oxadiazon@1.0 l/ha 3.10 ab 3.80ef 3.38 ab 3.93f 10.67 ab 28.66k 6.85abc 7.72ef t2oxadiazon@1.5 l/ha 3.11 ab 3.94d 3.40 ab 4.01e 11.23abc 30.43i 6.96abc 8.06de t3oxadiazon@2.0 l/ha 3.17 ab 4.14c 3.52 ab 4.18d 11.58 ab 34.73e 7.00abc 8.09d t4 oxadiazon@1.0 l/ha + hw at 45 dat 3.27 ab 4.35b 3.61 a 4.33c 11.56 ab 38.45c 6.98abc 8.56bc t5oxadiazon@1.5 l/ha + hw at 45 dat 3.08 ab 4.37b 3.58 a 4.55b 11.89abc 42.86b 7.04abc 8.89b t6 oxadiazon@2.0 l/ha + hw at 45 dat 3.54 ab 4.75a 3.65 ab 4.67a 13.20abc 44.58a 7.63 a 9.56a t7 pendimethalin@1.0 l/ha 3.10 ab 3.75f 3.41 ab 3.84g 10.48 bc 29.72j 6.29 bc 7.55f t8 pendimethalin@1.5 l/ha 3.41 a 3.87de 3.42 ab 3.97ef 9.49 abc 31.61h 6.51 bc 7.67f t9pendimethalin@1.0 l/ha + hw at 45 dat 3.12 ab 4.18c 3.74 a 4.15d 13.27 a 33.06g 7.29 ab 8.22cd t10 pendimethalin@1.5 l/ha + hw at 45 dat 3.19 ab 4.35b 3.51 ab 4.13d 12.24 ab 37.66d 6.92abc 8.57bc t11 weed free 2.85 bc 3.82ef 3.54 ab 3.76h 10.60 c 33.63f 6.07 c 7.44f t12-weedy check (control) 2.44 c 2.87g 3.09 b 2.95i 8.34 d 19.01l 4.22 d 6.28g level of significance ** ** * ** ** ** ** ** cv (%) 9.25 7.34 8.05 5.64 12.42 9.34 9.39 7.58 in a column, means followed by the same letter did not differ significantly by dmrt test. hw= hand weeding, dat =days after transplanting, * = 5% level of significance and ** = 1% level of significance. cost benefit analysis the economic performance of onion as influenced by different weed management practices are presented in the table 4. the highest gross return as well as benefit cost ratio (2.14 in 2016 and 2.46 in 2016) was found from the treatment t6 (oxadiazon@2.0 l/ha + hand at 45 dat) and the lowest benefit cost ratio(1.33 in 2016 and 1.74 in 2017) from treatment t11 (weed free). this is because hand weeding is very laborious than spraying of herbicides also expensive and time consuming. similar results also reported by panse et al. (2014). 88 islam et al. table 4. economic performance of onion as influenced by different treatments treatments total cultivation cost(tk. ha-1) gross return (tk. ha-1) bcr 2016-17 2017-18 2016-17 2017-18 2016-17 2017-18 t1 oxadiazon@1.0 l/ha 115000 115000 239750 270200 2.08 2.35 t2oxadiazon@1.5 l/ha 118000 118000 243600 282100 2.06 2.39 t3oxadiazon@2.0 l/ha 121000 121000 245000 283150 2.02 2.34 t4 oxadiazon@1.0 l/ha + hw at 45 dat 125000 131000 244300 299600 1.95 2.29 t5oxadiazon@1.5 l/ha + hw at 45 dat 126000 134000 246400 311150 1.96 2.32 t6 oxadiazon@2.0 l/ha + hw at 45 dat 125000 136000 267050 334600 2.14 2.46 t7 – pendimethalin@1.0 l/ha 127000 128000 220150 264250 1.73 2.06 t8 pendimethalin@1.5 l/ha 130000 130000 227850 268450 1.75 2.07 t9pendimethalin@1.0 l/ha + hw at 45 dat 133000 133000 255150 287700 1.92 2.16 t10 pendimethalin@1.5 l/ha + hw at45 dat 135000 135000 242200 299950 1.79 2.22 t11 weed free 160000 150000 212450 260400 1.33 1.74 t12-weedy check (control) 110000 125000 147700 219800 1.34 1.76 urea-tk. 16/kg, tsp-tk. 15kg-1, mop-tk.15 kg-1, gypsumtk. 10 kg-1, zinc sulphate –tk.100 kg-1, boric acid-tk. 100 kg-1, labourtk. 400man-1day-1, irrigation3000ha-1 irrigation-1, leas valuetk. 25000ha-1 for 5 months, seed-1500 kg-1, sale price-tk. 30 kg-1 bulb in 2016 and tk. 35 kg-1 bulb in 2017 . conclusion application of pre-emergence herbicide oxadiazon@2.0 l/ha with one hand weeding at 45 days after transplanting showed highest weed control efficiency, benefit cost ratio and increased bulb yield of onion. references bbs.2019. yearbook of agricultural statistics-2018.bangladesh bureau of statistics. statistics and informatics division (sid).ministry of planning. government of the people’s republic of bangladesh. dhaka. 30:133. boyham, g.e., d.m. granberry and w.t. kelley. 2016. green onions: commercial vegetable production.https://athenaeum.libs.uga.edu/bitstream/handle/10724/12353/c821. das, t.k. 2008. weed science: basics and applications. 1st edition: jain brothers publishers, new delhi. 901p. devulkar, n.g., d.r. bhanderi, s.j. more and b. jethava. 2015. optimization of yield and growth in onion through spacing and time of planting. green fmg. int. j. 6: 305-307. dunan, c.m., p. westra, f. moore and p.chapman.1996. modelling the effect of duration of weed competition, weed density and weed competitiveness on seeded, irrigated onion. weed res. 36: 259–269. ghoshel, h.z. 2004. single herbicide treatments for control of broadleaved weeds in onion (allium cepa l.) crop prot. 23: 539-542. impact of integrated weed management on bulb yield of onion 89 gomez, k.a. and a.a. gomez.1984. statistical procedures for agricultural research 2nd ed. john wiley & sons, new york. pp.146-184. james, r.l. and m.h.v. harlen. 2010. multiplication of reduced rate herbicides for weed control in onion. j. weed sci. technol. 24: 153-159. karim, m.m., m.h. khan, s. ghosh, a.s.m.y. ali and m.a. haque. 2014. effect of different doses of oxadiazon herbicide on weed control in onion field. eco-friendly agric. j. 7(10): 115-118. kizilkaya, a., h. onen and z. ozer. 2001. researches on the effects of weed competition on onion yield. j. turkish weed sci. 4(2): 58-65. misra, a.d., a. kumar and w.i. meitei. 2014. effect of spacing and planting time on growth and yield of onion var. n-53 under manipur himalayas. indian j. hort.71(2): 207-210. naresh, k., i.b. maurya and s.k. intodia. 2002. integrated weed management in onion (allium cepa l.) seed crop in vertisols of south rajasthan. intl. j. veg. sci. 29(2): 191-192. nargis, b., m.s. jilani and w. kashif. 2006. integrated weed management in different varieties of onion. indus. j. biol. sci. 3(1): 678-684. panse, r., a. gupta, p.k. jain, d.s. sasode and s. sharma. 2014. efficacy of different herbicides against weed flora in onion (allium cepa l.). j. crop weed.10(1): 163-166. patel, t.u., c.l. patel, d.d. patel, j.d. thanki, m.k. arvadia and h.b. vaidya. 2012. performance of onion under weed and fertilizer management. indian j. weed sci. 44(3): 151–158. qasem, j.r. 2006. chemical weed control in seedbed sown onion (allium cepa l.). crop prot. 25: 618-622. ray, n. and d.s. yadav. 2005. advance in vegetable production. research book center. new delhi. pp.237-238. smith, r., s.a. fennimore, s. orloff, g.j. poole, c.e. bell, d.w. cudney, s.a. fennimore and s. orloff. 2008. weeds (flint ml editor). uc ipm pest management guidelines: onion and garlic. university of california, agriculture and natural resources, publication. pp.34-53. syed, w.h. and m.f. malik. 2001. efficacy of cultural and chemical weed control in transplanted onion. j. biol. sci. 1(9): 825-827. uygur, s., r. gurbuz and f.n. uygur. 2010. weeds of onion fields and effects of some herbicides on weeds in cukurova region, turkey. african j. biotechnol. 9(42): 7037-7042. waiganjo, m.m. 2004. studies on the distribution, ecology and preventive management of thrips (thysanoptera: thripidae) on onion in kenya. phd thesis, kenyatta university, waiganjo, nairobi. 211p. bangladesh agron. j. 2020, 23(1): 29-36 influence of phosphorus levels on growth and yield of four lentil varieties r.a. sonet, m.h. ali, a.k.m.r. amin, m.n. haque and s.m. masum department of agronomy, sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka-1207, bangladesh corresponding e-mail: smmasum607@yahoo.com (received: 23 april, 2020, accepted: 07 june, 2020) keywords: lentil, phosphorus, variety, nodule, aez 28 abstract an adequate supply of phosphorus (p) is important for the proper growth and yield of lentil, particularly in poor fertile soil. as such an experiment was carried out to evaluate the effects of phosphorus (p) fertilizer application on growth, yield, and yield components of lentil at the agronomy research field of sher-e-bangla agricultural university, dhaka, bangladesh during 2013-201. four lentil varieties (bari masur-4, bari masur-5, bari masur-6, and bari masur-7) and four levels of p (0, 20, 40 and 60 kg p2o5 ha-1) were used in this experiment as treatment variables. interaction of cultivar and p levels showed a significant influence on all the plant characters studied except plant height and branch production. the highest seed yield (1.98 t ha-1) was obtained from the combination of bari masur-7 with 40 kg p2o5 ha-1, and the lowest (1.08 t ha-1) was from bari masur-5 with 0 kg p2o5 ha-1. addition of p fertilizer beyond 40 kg ha-1 decreased seed yield irrespective of varieties. results revealed that the application of p fertilizer offers a large scope for obtaining a higher yield of lentil in bangladesh. however, the application of p fertilizer at the rate of 40 kg p2o5 ha-1 would be the optimum for achieving higher yield irrespective of varieties. introduction pulses are the basic component of a cropping pattern in bangladesh as these crops suitable in crop rotation and diversified or intercropping systems followed under different agro-ecological regions. lentil (lens culinaris medik) locally known as masoor, is an important winter crop that has been grown as an important pulse for over 8,000 years (dhuppar et al., 2012). in bangladesh, lentil placed first position among the pulses in 154680.56 hectares, and production mt168837 (bbs, 2017). lentil share a rich source of dietary protein, macronutrients, micronutrients (fe, zn and se), and vitamins for poor consumers who cannot afford animal products due to high prices. despite its importance, the production of lentil in bangladesh is characterized by low mean yield of 1.27 t ha-1 (bbs, 2017) due to lack of improved variety. furthermore, variety plays an important role in producing a high yield of lentil because different varieties responded differently for their genotypic characters (hussain et al., 2002). among different released varieties of lentil in bangladesh: bari masur-4, bari masur-5, bari masur-6, and bari masur-7 are mentionable for high yield potential and quality. phosphorus (p) is a non-renewable and second most important macronutrient which is required for young tissues and performs several functions related to growth, development, and metabolism of the plant and also regulates many metabolic activities of the plant life. phosphorus increases the hardiness of the crop and an adequate supply of phosphorus results in rapid 30 sonet et al. growth (singh and singh, 2016). phosphorus is the key element for successful pulse production because it is involved in root development, stalk and stem strength, flower and seed formation, crop maturity and production, n-fixation, crop quality and resistance to plant diseases by enhancing the physiological functions. it plays an important role to stimulate biological activities like nodulation, nitrogen fixation, and nutrient uptake in soil and rhizosphere environment resulting in a higher yield of legume crops (khanam et al., 2016). the effect of phosphorus fertilization was significant on the number of pods plant-1 and grain yield (singh et al., 2003). the optimum phosphorus application enhances the yield attributes such as the number of pods plant-1, grains pod-1 and 1000-seed weight, resulting in high production (singh and singh, 2016). farmers usually grow lentil without any fertilizer. lentil suffering from p deficiency stimulates the length of the primary root, length and number of lateral roots and root hairs (sarker and karmoker, 2009), the increment in lateral roots was more than the primary root and resulted to increase in root surface area. the increase in the root surface area enhances the phosphorus acquisition from phosphorus-deficient soils, however, the varieties having prolific root hair formation are better in the acquisition of those nutrients (p, k, fe, mn, cu, zn, mo) which are less available in soil (gahoonia et al., 2006). the majority of soils under lentil cultivation in aez 28 of bangladesh are low to medium in available phosphorus, therefore, they respond well to the recommended level of phosphorus fertilizers (shil et al., 2016; rashid et al., 2018). there was, therefore, a need to study the effect of p fertilizer levels on the growth and yield of lentil genotypes. materials and methods the field experiment was conducted at the research field of the agronomy department, sher-ebangla agricultural university, dhaka (tejgaon series under aez 28) during the period december 2013 to april 2014. the experimental site was located at 23º77' n latitude and 903' e longitude with an elevation of 4.0 m from the sea level. the temperature during the cropping period ranged between 17.0ºc to 26.9ºc, the humidity 58.66% to 80.25% with 10.5-11.0 hours day length, and very little rainfall was recorded. the soil of the experimental site was silt loam in texture, with ph 6.4, organic carbon 0.68%, total nitrogen 0.08%, available phosphorus 10.99 mgkg-1, available potassium 0.05 meq100 g-1 and available sulphur10.5 mgkg-1. the climate of this area is subtropical with average monthly maximum and minimum temperature, rainfall, relative humidity of 27.34 c and 16.04 c, 62.34 mm, 66.53%, respectively. four lentil varieties (v1 = bari masur4, v2 = bari masur-5, v3 = bari masur-6, v4 = bari masur-7) and four levels of phosphorus (p0 = 0 kg p2o5 ha-1, p1 = 20 kg p2o5 ha-1, p2 = 40 kg p2o5 ha-1, p3 = 60 kg p2o5 ha-1) were used. the experiment was laidout in a splitplot design with three replications. different varieties of lentils were in the main plot and different levels of phosphorus in sub-plot. in this experiment phosphorus was applied as per treatment and urea (175 kg ha-1), mop (125 kg ha-1), gypsum (75 kg ha-1) were used as a recommended doses (frg, 2012). the whole amount of all fertilizers except p was applied as basal dose (during final land preparation). rate of p in the form of triple super phosphate (tsp) was used as per treatment and applied as a basal dose. sowing was done on 18 november 2013 in continuous rows at the rate of 35 kg ha-1. after sowing the seeds were covered with soil, slightly pressed by hand. the maturity of the crop was determined when 95% of the pods become brown. the data collected on different parameters were statistically analyzed and significant differences among the treatment means were compared by duncan’s multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). influence of phosphorus levels on growth and yield of lentil 31 results and discussion plant height plant height is a useful growth index that influences dry matter production and yield. although plant height is controlled genetically it may be modified by different agronomic practices. plant height was significantly influenced by variety and levels of phosphorus at 15 and 60 das but showed a non-significant effect at 30, 45, 75, and 90 das (table 1). the plant height of lentil increased significantly up to 60 kg p2o5 ha-1. variations in plant height due to varieties were also reported by hasan et al. (2015) and datta et al. (2013). increment in plant height might be due to the stimulation of biological activities in the presence of a balanced supply of phosphorus. similar results on the increased plant height with an increased level of phosphorus application have also been reported by other researchers (barua et al., 2011; datta et al., 2013). table 1. effect of variety and phosphorus on plant height of lentil at different days after sowing (das) variety × p2o5 level (kg ha-1) plant height (cm) at 15 das 30 das 45 das 60 das 75 das 90 das bari masur-4 0 10.57 a-c 12.52 17.70 19.47 b 27.67 29.10 20 10.57 a-c 12.57 19.83 27.87 ab 29.40 31.77 40 11.55 a-c 12.30 20.43 27.07 ab 30.20 32.07 60 10.83 a-c 13.17 20.00 31.67 a 30.97 32.07 bari masur-5 0 10.77 a-c 12.47 17.53 25.17 ab 26.87 29.97 20 10.20 bc 12.53 19.27 27.63 ab 29.07 30.17 40 10.89 a-c 13.50 20.17 26.73 ab 29.07 31.17 60 11.33 a-c 14.93 21.13 25.77 ab 30.73 31.53 bari masur-6 0 10.53 a-c 12.67 19.43 25.97 ab 27.30 26.97 20 10.13 c 12.37 19.40 27.43 ab 27.40 28.17 40 10.77 a-c 12.67 19.63 27.30 ab 28.43 30.43 60 10.63 a-c 12.47 19.67 27.17 ab 28.63 30.53 bari masur-7 0 12.60 a 12.87 19.83 27.10 ab 29.17 26.53 20 11.50 a-c 14.50 20.07 27.40 ab 31.43 29.50 40 12.30 ab 12.83 20.97 29.97 a 30.97 31.40 60 10.83 a-c 14.50 21.23 27.40 ab 32.87 31.63 se(0.05) 0.61 1.18 1.39 2.45 1.74 1.76 cv (%) 9.65 15.60 12.22 15.78 10.28 10.09 any two means not sharing the same letter differ significantly at 5% level of probability (dmrt) nodule number plant-1 nodule production plant-1 was significantly influenced by varieties and different levels of phosphorus at 15, 30, 45, 60, 75, and 90 days after sowing (table 2). at 60 days after sowing the highest number of the nodules plant-1 (13.33) was found from the combination of bari masur-6 with60 kg p2o5 ha-1. at 15 days the lowest number of the nodules plant-1 (0.333) was found from bari masur-4 with 0 kg p2o5 ha-1. the number of nodules increases as the plant grows, and normally reaches the maximum at the mid flowering stage when the plant needs n the most (jindal et al., 2008). datta et al. (2013) observed that numbers of nodule production in lentil increase with the increasing the phosphorus level. the symbiotic parameters i.e. nodulation, nodule dry weight, and leghaemoglobin content are positively influenced by phosphorus application (rashid et al., 2018). so, proper application of p to lentil facilitates the 32 sonet et al. earlier formation of nodules, increasing their numbers which enhances the nitrogen fixation (gahoonia et al., 2006). thus, p increases the yield of lentil by stimulating physiological functions and root development that improve nodulation (sharma and sharma, 2004). the increasing dose of p from 20 to 60 kg p2o5 ha-1 increased the nodules and their dry weight per plant (jindal et al., 2008). the number of nodules per plant declined at the highest dose (80 kg ha-1) of p (rasheed et al., 2010). effective branches plant-1 the number of effective branches plant-1 is one of the most important yield contributing characters in lentil. effective branches plant-1 was significantly influenced by variety and different levels of phosphorus applications (table 3). the highest number of effective branches plant -1 (8.00) was found from bari masur-7 with 40 kg p2o5 ha-1 and the lowest number of effective branches (4.00) from bari masur-5 with 0 kg p2o5 ha-1. patil et al. (2003) and hussain et al. (2002) also reported that effective branches plant-1 also vary with variety and different levels of p. table 2. effect of variety and phosphorus on nodule production of lentil at different das variety × p2o5 level (kg ha-1) number of nodules plant-1at 15 das 30 das 45 das 60 das 75 das 90 das bari masur-4 0 0.33 d 1.00 c 2.00 b 6.00 cd 4.33 de 2.67 fg 20 1.33 a-d 1.67 bc 2.33 ab 8.33 bc 5.33 b-e 4.33 c-g 40 2.33 a 2.67 a 2.67 ab 10.67 ab 5.33 b-e 5.00 b-g 60 1.67 a-c 1.67 bc 2.67 ab 11.67 ab 7.67 a-c 7.00 a-c bari masur-5 0 0.67 cd 1.33 bc 2.00 b 2.67 e 3.33 e 3.33 e-g 20 1.00 b-d 1.00 c 2.67 ab 3.67 de 5.00 c-e 4.00 d-g 40 1.67 a-c 2.00 ab 2.67 ab 6.33 cd 6.33 a-e 4.67 c-g 60 1.67 a-c 2.00 ab 2.67 ab 9.00 bc 7.33 a-d 5.33 b-f bari masur-6 0 0.67 cd 1.33 bc 2.33 ab 8.33 bc 5.33 b-e 2.33 g 20 1.33 a-d 1.67 bc 1.67 b 11.33 ab 6.00 a-e 4.33 c-g 40 2.00 ab 2.00 ab 2.33 ab 11.33 ab 6.00 a-e 6.33 a-d 60 2.00 ab 2.00 ab 3.33 a 13.33 a 8.33 ab 7.67 ab bari masur-7 0 1.33 a-d 1.67 bc 1.67 b 4.00 de 5.00 c-e 2.33 g 20 2.00 ab 2.00 ab 2.33 ab 6.33 cd 7.67 a-c 5.67 b-e 40 1.67 a-c 2.00 ab 2.67 ab 10.00 ab 8.00 a-c 6.67 a-d 60 1.67 a-c 1.67 bc 3.33 a 10.00 ab 8.67 a 8.67 a se(0.05) 0.304 0.236 0.323 1.042 0.923 0.835 cv (%) 36.14 23.61 22.74 21.71 25.66 28.80 any two means not sharing the same letter differ significantly at 5% level of probability (dmrt) number of filled pods plant-1 pods plant-1is an important parameter determining the seed yield of the crop. it is clear from the data given in table 3 that number of filled pods plant-1 was significantly influenced by the combination of varieties and different levels of phosphorus application. the highest number of filled pod plant-1 (73.0) was found from bari masur-7 with 40 kg p2o5 ha-1 and the lowest filled pod plant-1 (26.33) from bari masur-5 with 0 kg p2o5 ha-1. datta et al. (2013) mentioned that numbers of pod in lentil significantly varied due to var iations of variety and p levels. it might be the reason for moderate plant nutrients availability due to which the plant produces more pods plant-1 as compare to other treatments and also phosphorus strongly influence of phosphorus levels on growth and yield of lentil 33 increases the reproduction of the plants i.e. flowering and fruiting. furthermore, p fertilization might stimulate the plant for flowering and fruiting which leads to producing more pods (maqsood et al., 2000). number of seeds pod-1 the number of seeds pod-1 is also an important yield contributing parameter which has a great effect on final yield. it was observed that the treatment combination of variety and phosphorus had a significant effect on number of seeds pod-1 (table 3). the highest number of seeds pod-1 (1.97) was found for the treatment bari masur-6 with 40 kg p2o5 ha-1 and bari masur-7 with 40 kg p2o5 ha-1 while the lowest number of seeds pod-1 (1.64) from bari masur-4 with 0 kg p2o5 ha-1. the used plant materials are the modern variety of lentils in bangladesh therefore variation was mainly due to application of different phosphorus levels. hussain et al. (2002) reported that the number of seed pod-1 varied greatly with varieties in lentil. zeidan (2007) reported that increasing phosphorus levels from 0 to 60 kg increased seeds pod-1. the numbers of seeds pod-1 are enhanced with a successive increase in p levels from 20 to 40 and 60 kg ha-1 (choubey et al., 2013). the increment in p accumulates the photosynthesis from growing organs to seeds leading to make them plump and bold, thus affect the seed size and weight. hence, seeds pod-1can be improved by superior p fertilization. 1000-seed weight seed weight is an important quality parameter of crops which has a great effect on final yield. although this character is genetically controlled, the growing condition also exerts considerable influence on its expression. it is observed that the treatment combination of variety and phosphorus had a significant effect on 1000-seed weight (table 3). the highest 1000-seed weight (26.67 g) was found from bari masur-6 with 40 kg p2o5 ha-1 whereas the lowest (20.33 g) from bari masur-4 with 0 kg p2o5 ha-1. table 3. effect of variety and phosphorus on yield contributing parameters and yield of lentil variety × p2o5 level (kg ha-1) effective branch plant-1 (no.) filled pods plant-1 (no.) seeds pod-1 (no.) 1000-seed weight (g) seed yield (t ha-1) bari masur-4 0 4.33 fg 35.00 d-f 1.64 b 20.33 c 1.11 de 20 5.33 d-g 53.00 b-d 1.77 ab 21.33 a-c 1.48 c-e 40 6.33 a-e 61.00 a-c 1.91 ab 26.33 ab 1.56 bc 60 6.33 a-e 55.67 a-c 1.78 ab 23.67 a-c 1.51 cd bari masur-5 0 4.00 g 26.33 f 1.66 ab 21.33 a-c 1.08 e 20 5.00 e-g 48.67 c-e 1.74 ab 21.67 a-c 1.42 c-e 40 6.00 b-f 62.67 a-c 1.90 ab 25.33 a-c 1.54 bc 60 5.67 c-g 55.00 a-c 1.75 ab 21.33 a-c 1.44 c-e bari masur-6 0 5.67 c-g 33.00 ef 1.74 ab 21.00 bc 1.37 c-e 20 6.67 a-e 51.33 b-e 1.93 ab 23.00 a-c 1.74 a-c 40 7.33 a-c 68.67 ab 1.97 a 26.67 a 1.79 a-c 60 7.00 a-d 54.00 a-d 1.71 ab 24.00 a-c 1.79 a-c bari masur-7 0 5.33 d-g 35.67 d-f 1.69 ab 22.00 a-c 1.39 c-e 20 7.33 a-c 53.00 b-d 1.89 ab 22.00 a-c 1.73 a-c 40 8.00 a 73.00 a 1.97 a 26.00 ab 1.98 a 60 7.67 ab 53.67 b-d 1.91 ab 25.33 a-c 1.95 ab se(0.05) 0.569 5.734 0.095 0.124 0.124 cv (%) 16.08 19.39 9.02 13.73 13.73 any two means not sharing the same letter differ significantly at 5% level of probability (dmrt) 34 sonet et al. variation in 1000-seed weight in different varieties was also reported by datta et al. (2013) in lentil. saxena and varma (1996) also obtained a significant effect on 1000-seed weight and the highest was recorded from 30 to 60 kg p2o5 ha-1which is conformity with the present results. in lentil increasing level of p from 20 to 80 kg ha-1 significantly increase the time of field maturity (rasheed et al., 2010) because p stimulates the nitrogenase activity of root nodules and physiological processes (khan et al., 2006). so, higher p rates application lengthen the period of crop maturity and consequently increase the seed yield, by improving 1000-seed weight (rasheed et al., 2010). seed yield seed yield is the output of different treatments applied as well as the effect of different agronomic practices and the environment. the variation in seed yield might be due to differences in yield attributing parameters like the number of pods plant-1, seeds pod-1, and test weight among the varieties which are influenced by the phosphorus fertilizer application (table 3). the yield varied from 1.08 to 1.98 t ha-1 due to different levels of p and varieties. the highest seed yield (1.98 t ha-1) was found from bari masur-7 with 40 kg p2o5 ha-1. however, the increase in seed yield of bari masur-4, bari masur-5, bari masur-6 and bari masur-7 were 40, 43, 31 and 43%, respectively compared to the controls. this indicates the fact that agronomic biofortification may have fostered the photosynthesis process and translocation of photosynthetic products to the seed as a result of an increase in enzymatic activity (islam et al., 2018). an increase in phosphorus fertilizer beyond 40 kg ha-1 tended to decrease seed yield irrespective of varieties. this might be due to the imbalance of other nutrients. similar findings were also obtained by singh et al. (2005) who reported that increased phosphorus application demonstrated a higher yield of lentil at a certain level. conclusion the agronomic biofortification had influenced the plant height, branch plant-1, and importantly, the number of nodules plant-1. so, optimum management of p is necessary to harvest the full potential of the lentil crop cultivated on low to medium p status soils. the combination effect revealed that lentil var. bari masur-7 with 40 kg p2o5 ha-1 performed best in producing a higher seed yield. therefore, it could be concluded that var. bari masur-7 with 40 kg p2o5 ha1may be a promising practice for obtaining a higher seed yield of lentil under aez 28 of bangladesh. references barua, r., m.s.u. bhuiya, m.m. kabir, s. maniruzzamanand z. ahmed. 2011. effects of mimosa (mimosa invisa) compost and phosphorus on the yield and yield components of lentil (lens culinaris l.). the agriculturists. 9: 63-72. bbs (bangladesh bureau of statistics). 2017. yearbook of agricultural statistics. statistics and information division, ministry of planning. government of the people’s republic of bangladesh, dhaka-1207. choubey, s.k., v.p. dwivedi and n.k. srivastava. 2013. effect of different levels of phosphorus and sulphur on growth, yield and quality of lentil (lens culinaris m). indian j. sci. res. 4: 149150. datta, s.k., m.a.r. sarkar and f.m.j. uddin. 2013. effect of variety and level of phosphorus on the yield and yield components of lentil. intl. j. agril. res. innov. tech. 3(1): 78-82. influence of phosphorus levels on growth and yield of lentil 35 dhuppar, p., s. biyan, b. chintapalli and s. rao. 2012. lentil crop production in the context of climate change: an appraisal. indian res. j. ext. edu. 2(special issue): 33-35. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council, khamarbari, farmgate, dhaka. p.31. gahoonia, t.s., o. ali, a. sarker, n.e. nielsen and m.m. rahman. 2006. genetic variation in root traits and nutrient acquisition of lentil genotypes. j. plant nutr. 29: 643-655. gomez, k.a. and a.a. gomez. 1984. statistical procedure for agricultural research (2nd ed.). international rice research institute. jhon wiley and sons, inc. singapore. pp.139-240. hasan, a.k., m. ashiquzzaman, q.f. quadir and i. ahmed. 2015. phosphorus use efficiency of different varieties of lentil and grasspea. res. agric. livest. fish. 2(2): 271-277. hussain, m., s.h. shah and s.m. nazir. 2002. differential genotypic response to phosphorus application in lentil (lens culinaris medic). intl. j. agric. biol. 4: 61-63. islam, m.m., m.r. karim, m.m.h. oliver, t.a. urmi, m.a. hossain and m.m. haque. 2018. impacts of trace element addition on lentil (lens culinaris l.) agronomy. agron. 8: 100, doi:10.3390/agronomy8070100. jindal, c., v. khanna and p. sharma. 2008. impact of rhizobium and psb inoculation on peconomy, symbiotic parameters and yield of lentil (lens culinaris medikus). j. res. punjab agri. univ. 45: 1-3. khan, h., f. ahmad, s.q. ahmad, m. sherin and a. bari. 2006. effect of phosphorus fertilizer on grain yield of lentil. sarhad j. agric. 22: 433-436. khanam, m., m.s. islam, m.h. ali, i.f. chowdhury and s.m. masum. 2016. performance of soybean under different levels of phosphorus and potassium. bangladesh agron. j. 19: 99108. maqsood, m., m.s.i. zamir, r. ali, a. wazid and n. yousaf. 2000. effect of different phosphorous levels on growth and yield performance of lentil (lens culinaris medik). pakistan j. biol. sci. 3: 523-524. patil, b.l., v.s. hegde and p.m. salimath. 2003. studies on genetic divergence over stress and non-stress environment in mungbean. indian j. gen. plant breed. 63(1): 77-78. rasheed, m., g. jilani, i.a. shah, u. najeeb and t. iqbal. 2010. improved lentil production by utilizing genetic variability in response to phosphorus fertilization. soil plant sci. 60: 485493. rashid, m.a., t.m.b. hossain, m.e. hoque, m.m. rahman and k.s. rahman. 2018. adoption of lentil varieties in bangladesh: an expert elicitation approach. bangladesh j. agril. res. 43(1): 159-168. sarker, b.c. and j.l. karmoker. 2009. effects of phosphorus deficiency on the root growth of lentil seedlings (lens culinaris medik) grown in rhizobox. bangladesh j. bot. 38: 215-218. saxena, k.k. and v.s. varma. 1996. effect of n, p and k on the growth of yield of lentil (lens culinaris). indian j. agron. 40(2): 249-242. sharma, b.c. and s.c. sharma 2004. integrated nutrient management in lentil. adv. plant sci. 17: 195-197. shil, n.c., m.a. saleque, m.r. islam and m. jahiruddin. 2016. soil fertility status of some of the intensive crop growing areas under major agro-ecological zones of bangladesh. bangladesh j. agril. res. 41(4): 735-757. singh, k.k., c. srinivasarao and m. ali. 2005. root growth, nodulation, grain yield, and phosphorus use efficiency of lentil as influenced by phosphorus, irrigation, and inoculation. commun. soil sci. plan. 36: 1919–1929. 36 sonet et al. singh, n. and g. singh. 2016. response of lentil (lens culinaris medikus) to phosphorus-a review. agric. rev. 37(1): 27-34. singh, o.n., m. sharma and r. dash. 2003. effect of seed rate, phosphorus and fym application on growth and yield of bold seeded lentil. indian j. pulses res. 16: 116-118. zeidan, m.s. 2007. effect of organic manure and phosphorus fertilizers on growth, yield and quality of lentil plants in sandy soil. res. j. agric. biol. sci. 3(6): 748-752. bangladesh agron. j. 2022, 25(1): 129-138 intercropping of cauliflower with sweet gourd at different plant population m.m. khanum1, m.s. huda1, m. nuruzzaman2, m.a.a.a. muzahid3 and m.m. alam4 1agronomy division, 2on-farm research division, ars, bari, rajbari, dinajpur, 3department of horticulture, bau, mymensingh-2202, 4agronomy division, rars, bari, hathazari, chattogram corresponding e-mail: mahbuba.bari27@gmail.com (received: 23 june 2022, accepted: 06 july 2022) keywords: sweet gourd, cauliflower, intercropping, ler, monetary return abstract intercropping is a popular way to boost crop yield and profitability by maximizing the use of natural and agricultural resources. a study was carried out to establish crop arrangement for sweet gourd and cauliflower intercropping systems. the experiment was carried out during two consecutive years of 2019-20 and 2020-21 to identify the appropriate cauliflower population for intercropping with sweet gourd for increased production and profitability. seven treatments viz. t1= sole sweet gourd (2 m  2 m), t2=100% sweet gourd + 3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd + 3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd + 4 rows cauliflower 50% (50 cm  50 cm), t5=100% sweet gourd + 4 rows cauliflower 31% (50 cm  80 cm), t6=100% sweet gourd + 5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm). the maximum sweet gourd equivalent yield (sgey) 34.83 t ha-1 was obtained from t4. the maximum gross return (tk. 278640 ha-1), gross margin (tk. 180384 ha-1), bcr (2.85) and ler (1.40) were also observed from t4 and the lowest in sole cauliflower (t7). the overall results revealed that among the intercrop combinations 100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm) (t4) followed by 100% sweet gourd + 3 rows cauliflower 37.5% (60 cm  50 cm) (t2) combinations could be profitable combinations for cauliflower with sweet gourd intercropping system. introduction intercropping is a popular strategy used in modern agricultural systems to increase productivity and yield stability while minimizing resource use and impact on environmental (alizadeh et al., 2010). intercropping advantages include increased output or production, more effective use of water, land, nutrients and labor and a significant decline in insect, disease, and weed problems (awal et al., 2006). vegetables are grown on 2.63 percent of cultivable land in bangladesh (bbs, 2015). malnutrition is unlikely to arise if people consume an adequate amount of vegetables. in bangladesh, the average daily vegetable consumption per capita is 56 grams, but the recommended daily intake is 250 grams (fao, 2015). in bangladesh, the output of vegetables, such as sweet gourd (cucurbita maxima), is steadily growing. it occupied 42636 acres of land in bangladesh, with a total production of 186112 metric tons (bbs, 2016). sweet gourd is often cultivated with greater row spacing and inter row space may be efficiently and effectively utilized for maximum production. as a result, farmers may easily intercrop short duration crop with sweet gourd at an early stage of growth. as a result, farmers may easily plant a short-term crop as an intercrop with sweet gourd at an early stage of growth. cauliflower (brassica oleracea l. var. botrytis) is the most widely produced vegetable in the country in terms of crop cultivated area of 47749 acres of land with a total production of 268484 metric tons (bbs, 2016). cauliflower is a high-value, short-duration (60-70 days) rabi crop which gives early return by suitable 130 khanum et al. appropriate crops, population density, and planting geometry for component crops might result in improved intercrop productivity (santalla et al., 2001). however, there is little literature on population density and planting geometry of intercropping cauliflower with a wide spacing sweet gourd crop. as such, the experiment was carried out to determine the cauliflower population for intercropping with sweet gourd for increased production and economic return. materials and methods experimental site description the experiment was carried out at the agricultural research station, bangladesh agricultural research institute (bari), rajbari, dinajpur, during two consecutive rabi season of 2019-20 and 2020-21. the experimental site was located at latitude: 25°38̍7.3̎ n and longitude: 88°39̍5.65̎ e at an elevation of 39 m above mean sea level and it belongs to the agro-ecological zone-1 (old himalayan piedmont plain) in bangladesh (frg, 2018). the initial soil sample (0-15 cm) was tested at the soil resources development institute (srdi), dinajpur, bangladesh (table 1). the soil at the experimental area was medium-high and clay loam texture having 2.19% organic matter, ph 6.05, 0.10% total nitrogen (n), 0.13meq 100 g-1 soil potassium (k), 47.20μg/g phosphorus (p), 8.12μg/g sulfur (s),0.91μg/g zinc (zn) and 0.33 μg/g boron (b). during crop growth period, monthly weather data on temperature (maximum and minimum) and rainfall (mm) were recorded in both the years (figure 1). the average maximum and minimum temperature in the crop season (november to april) were 27.1°c and 15.04°c, 28.53°c and 15.33°c during in 2019-20 and in 2020-21, respectively. during the crop season, the experimental site's weather is hot sub-humid with total rainfall of 129 mm in 2019-20 and 25 mm in 2020-21. experimental design and treatments the experiment was conducted in a randomized complete block design with three replications to test the effectiveness of sweet gourd and cauliflower intercropping. the unit plot size was 16 m2 (4 m  4 m). sweet gourd was the major crop while cauliflower as an intercrop. the experiment consisted of seven treatments viz., t1=sole sweet gourd (2 m  2 m), t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm), t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm), t6=100% sweet gourd +5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm). crop husbandry sweet gourd var. bari misti kumra-2, and cauliflower var. bari fulcopy-1 was used in this experiment. twenty-five days old seedlings of cauliflower were transplanted on 12 november, 2019 and 10 november, 2020. fifteen days old seedlings of sweet gourd were transplanted on 27 november, 2019 and 25 november, 2020. the recommended doses of fertilizers such as, 75-36-60-21-2-1.4 kg n, p, k, s, zn and b ha-1 and 90-45-75-18-2.4-1.4 kg n, p, k, s, zn and b ha-1 for sole crop of sweet gourd and cauliflower, respectively were applied separately in sole crop. in intercropping sweet gourd was fertilized with 90-55-85-22-2.4-2 kg n, p, k, s, zn and b ha-1 in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid, respectively (frg, 2018). cowdung @ 5 t ha-1 were applied as a blanket dose during final land preparation. all of organic manure and chemical fertilizers were applied at final land preparation, while urea and mop were top dressed in three equal splits at 15, 30 and 50 dat of cauliflower. the full amount of p, k, s, zn and b and cowdung were applied in pit 7 days before transplanting of sweet gourd seedlings. n was be applied around the plant as side dressing at 15, 30, 50 and 70 dat under moist soil condition and mixed thoroughly with the soil. four irrigations were provided after applying of urea. fungicide indofil m @ 0.2% was sprayed at every 15 days interval to control powdery mildew on sweet gourd. cucurbit fruit fly was controlled in the sweet gourd field using pheromone traps (cue lure) @100 traps per hectare from 30 days after planting through sweet gourd harvesting. harvesting of sweet gourds began intercropping cauliflower with sweet gourd 131 at 105 dat and was repeated four times in both years. cauliflower was harvested three times (74, 80 and 84 dat) in two consecutive years. assessment of economic indices the economic analysis took total variable costs (tvc), gross returns (gr), gross margin (gm) and bcr into account. the variable costs included human labour, machinery rent and production inputs (seed, fertilizer, pesticides). gross returns were determined by multiplying crop economic yield by price at harvesting time. the difference between gr and tvc was used to determine the gross margin (gm) (gm= gr-tvc). various competition functions such as sweet gourd equivalent yield (sgey), land equivalent ratio (ler), replacement value of intercropping (rvi), monetary advantage index (mai), aggressivity index (a), relative crowding coefficient (rcc), system productivity index (spi), competitive ratio (cr) and benefit-cost ratio was calculated to determine the benefit and effect of competition among the treatments. the competition functions were calculated by using the following formula: sweet gourd equivalent yield the sweet gourd equivalent yield (sgey) was calculated using the following formula: sweet gourd equivalent yield (sgey)= yisg + yic×pc psg where, yisg= yield of intercrop sweet gourd, yic= yield of intercrop cauliflower, psg = price of sweet gourd, pc= price of cauliflower land equivalent ratio the following formula was used to compute the land equivalent ratio (ler) ler= (yisg/yssg) + (yic/ysc) here, yisg = intercrop yield of sweet gourd; yssg = sole crop yield of sweet gourd; yic = intercrop yield of cauliflower; ysc= sole crop yield of cauliflower (ofori and stern, 1987 and willy, 1979). replacement value of intercropping replacement value of intercropping (rvi) and monetary advantage index (mai) was calculated according to moseley (1994) and ali and mishra (1993), respectively. rvi= yisg×psg+yic×pc yssg×psg-cssg where, yisg & yic are the yield of intercrops, psg & pc are the respective market price of these crops, yssg & cssg are the yield and input cost of the main crop in sole stand. monetary advantage index the monetary advantage index was computed in the method stated by (ghosh, 2004). mai = value of combined intercrop yield×(ler-1)/ler. aggressivity index the following formula was used to determine the aggressivity index (a) a sweet gourd= yisg yic yssg×zssg ysc×zcp and acauliflower = yic yisg ysc×zcp yssg×zsgp where, yisg & yic are the yield of intercrops, yssg&ysc are yield of sole crops and zsgp and zcp are the proportion of sweet gourd and cauliflower, respectively (banik et al., 2006 and khan et al., 2018). relative crowding coefficient: the following formula was used to compute the relative crowding coefficient (rcc): rccsweet gourd× rcccauliflower, where, rccsweet gourd= yisg×zcp (yssg-yisg)×zsgp and rcc cauliflower= yic×zsgp (ysc-yic)×zcp where zsgp and zcp are the proportion of sweet gourd and cauliflower in the mixture, respectively. 132 khanum et al. system productivity index the following formula was used to estimate the system productivity index (spi) system productivity index (spi)= yssg × (yic+yisg) ysc where, yssg & ysc are yield of sole crops and yisg&yic are the yield of intercrops (willey, 1979). competitive ratio the competitive ratio (cr) among various treatment combinations was estimated usingthe formula below (willey and rao, 1980): cr sweet gourd = lersweet gourd × zcp ler cauliflower zsgp and crcauliflower = lercauliflower × zsgp ler sweet gourd zcp where, zsgp and zcp are the proportion of sweet gourd and cauliflower in the mixture, respectively. benefit-cost ratio the benefit-cost ratio (bcr) was carried out using the current price of sweet gourd and cauliflower in the local market at the time of harvesting. benefit-cost ratio (bcr)was calculated using the following formula (hossain et al., 2015): bcr = gross return total variable cost data recorded and statistical analysis data on fruit plant-1, fruit length, fruit diameter, single fruit weight, and fruit yield of sweet gourd were collected from selected 4 plants from each plot. data on plant height, curd diameter, individual curd weight and yield were recorded from ten randomly selected plants from each plot. yields of both the crops were taken from whole plot. collected data of all crops were analyzed (combined analysis) statistically by using r software packages (r core team, 2016) and mean differences for each character were compared by least significant difference (lsd) at 5% level of significance (gomez and gomez, 1984). table 1. initial status of soils of the experimental plots at ars, bari, rajbari, dinajpur soil characteristic ph organic matter (%) total n (%) available p (μg/g) k (meq/100g) s (μg/g) zn (μg/g) b (μg/g) initial 6.05 2.19 0.10 47.20 0.13 8.12 0.91 0.33 status sa m l vh l l m m sa=slightly acidic, m=medium, l=low, vh=very high fig. 1. monthly average maximum temperature, minimum temperature and rainfall during the cropping period in both years of experimentation. intercropping cauliflower with sweet gourd 133 results and discussion yield and yield contributing characters of sweet gourd: the number of fruit plant-1, fruit length, fruit diameter, single fruit weight and fruit yield of sweet gourd were affected significantly by intercrop combination and sole cropping (table 2). the highest number of fruit plant-1 (4.01) was obtained from sole sweet gourd (t1) and the lowest 3.02 from t4 treatment. sole sweet gourd (t1) gave the highest fruit length (26.25 cm) and diameter (20.88 cm) which was followed by t3 treatment (25.82 cm length and 20.08 cm diameter) and the lowest fruit length (24.77 cm) and diameter (19.62 cm) were measured in t4. the maximum single fruit weight (2.81 kg) was obtained from sole sweet gourd (t1) which was followed by t3 (2.60 kg) and the lowest (2.18 kg) in t4. the highest fruit yield 25.20 t ha-1 was obtained from sole sweet gourd (t1) and the lowest (20.01 t ha-1) in t4. the yield of sweet gourd in different treatments varied from 19.98 to 25.20 t ha-1 where 12.34 to 21 % yield reduction was recorded in intercropping systems than sole sweet gourd (t1). intercropping systems resulted in a 15.51% lower yield than sole cropping systems (islam et al., 2013). in the present study, highest fruit plant-1, fruit length, fruit diameter, single fruit weight and finally fruit yield of sweet gourd were obtained from sole cropping and among the intercropping where a less number of cauliflower population (table 2). table 2. yield contributing characters and fruit yield of sweet gourd in sweet gourdcauliflower intercropping system (pooled of 2 years) treatments fruits plant-1 (no.) fruit length (cm) fruit diameter (cm) single fruit weight (kg) fruit yield (t ha-1) t1 4.01 26.25 20.88 2.81 25.20 t2 3.42 24.37 19.37 2.21 20.01 t3 3.50 25.82 20.08 2.60 22.09 t4 3.02 24.77 19.62 2.18 19.98 t5 3.48 25.04 19.90 2.30 20.34 t6 3.32 24.79 19.65 2.20 20.15 lsd (0.05) 0.34 1.91 1.46 0.55 2.23 cv (%) 6.53 1.55 3.40 8.70 6.42 t1=sole sweet gourd (2m  2m), t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm), t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm) and t6=100% sweet gourd+5 rows cauliflower 31% (40 cm  100 cm) these results were consistent with the findings of hossain et al. (2015) who reported that the yield of sweet gourd in different treatments varied from 12.16 to 17.12 t ha-1 where 1.34 to 28.93% yield reduction was recorded in intercropping system than sole sweet gourd. this was due to competition of cauliflower population with sweet gourd and shading effect of cauliflower, which seriously affected the vegetative growth of the seedlings resulting drastically reduced the fruit yield of sweet gourd. the results were in agreement with the findings of alom et al. (2014). yield contributing characters and curd yield of cauliflower: yield contributing characters and curd yield of cauliflower were significantly influenced by the intercropped of different cauliflower population in sweet gourd (table 3). the maximum plant height (52.66 cm), curd diameter (17.45 cm), individual curd weight (1073.33 g) were recorded in (t3) which was followed by t5 treatments. while the lowest (889.89 g) in sole cauliflower (t7). however, the highest cauliflower yield 32.50 t ha-1 was recorded in sole cauliflower (t7). on the other land, the highest cauliflower yield under intercrop situation was recorded in t4 (19.80 t ha-1) which was followed by t2 (15.82 t ha-1). the lowest cauliflower yield 11.12 t ha-1 was recorded from t3 in two consecutive years. in the present study, the planting arrangement significantly influenced cauliflower yield in different intercropping combinations were due to the different plant population of cauliflower in per unit area (table 3). increase of cauliflower population with sweet gourd, increased the curd yield of cauliflower. the cauliflower yield varied in different treatment might be due to the variation of number of cauliflowers of that treatment. 134 khanum et al. table 3. yield contributing characters and curd yield of cauliflower in sweet gourdcauliflower intercropping system (pooled of 2 years) treatments plant height (cm) curd diameter (cm) individual curd weight (g) curd yield (t ha-1) t2 48.33 16.50 900.20 15.82 t3 52.66 17.45 1073.33 11.12 t4 45.00 16.02 920.33 19.80 t5 50.00 17.11 990.16 14.17 t6 49.00 16.76 950.09 15.01 t7 43.67 15.86 889.89 32.50 lsd (0.05) 4.76 1.58 92.26 1.91 cv (%) 5.44 4.85 6.04 4.32 t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm50 cm), t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm) and t6=100% sweet gourd+5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm) sweet gourd equivalent yield (sgey): sweet gourd equivalent yield gave higher (30.43-34.83 t ha-1) in all the intercropping system over sole crop of sweet gourd (25.20 t ha-1) (table 4). the highest sweet gourd equivalent yield (34.83 t ha-1) was recorded from sweet gourd (100 %) + 4 rows of cauliflower (50 %) (t4) which covered the yield advantages of 21 and 40 % over their respective sole crops. this yield advantage might be attributed to the combined yield of both crops. intercropping has been shown to produce greater biomass and as a result, make better use of land and available resources than sole cropping. similar results were observed by rahman et al. (2015), hossain et al. (2015) and khanum et al. (2019). economic performance: intercropping cauliflower with sweet gourd resulted in a higher gross return and gross margin than growing cauliflower as a single crop. 100% sweet gourd + 4 rows cauliflower 50% (50 cm  50 cm) was obtained the maximum gross return tk. 278640 ha-1 which gave additional benefit of tk. 201600 ha-1 over sole sweet gourd and tk. 195000 ha-1 over sole cauliflower (table 4). total cultivation cost was reduced in sole crop and higher in intercropping treatments due to the addition of component crop. among the intercropping systems, 100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm) (t4) obtained the highest benefit cost ratio of 2.85 which further indicated the superiority to t4 over other treatments. these findings were consistent with those of bharati et al. (2007) who found that sweet gourd intercropping had a greater net return than a single sweet gourd crop. these findings were consistent with those of rahman et al. (2015), hossain et al. (2015) and khanum et al. (2019) who found that intercropping systems had a higher gross margin or net return than sole crops. table 4. sweet gourd equivalent yield (sgey) and economics of intercropping sweet gourd with cauliflower (mean data of 2 years) treatments sgey (t ha-1) gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 25.20 201600 81805 119795 2.46 t2 31.87 255000 96015 158985 2.66 t3 30.43 243440 95500 147940 2.55 t4 34.83 278640 98256 180384 2.85 t5 30.96 247740 95640 152100 2.59 t6 31.40 251260 95640 155620 2.63 t7 24.37 195000 92500 102500 2.10 sg = sweet gourd, sgey= sweet gourd equivalent yield, tvc = total variable cost market price (tk kg-1): sweet gourd 8/-, cauliflower 6/ t1=sole sweet gourd (2m2m), t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm), intercropping cauliflower with sweet gourd 135 t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm) and t6=100% sweet gourd+5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm) land equivalent ratio (ler): based on a two-year average and regardless of planting combinations, the maximum ler value (1.40) was found in t4 (100% sweet gourd + 4 rows cauliflower 50% (60 cm  50 cm) intercropping system against the minimum for t3 (100% sweet gourd + 3 rows cauliflower (60 cm  80 cm) (1.21) indicating that the yield advantages ranged between 21-40%. in this study, the ler of sweet gourd and cauliflower intercropping was 1.32-1.42 (2019-2020) and 1.29-1.40 (20202021) respectively, demonstrating the clear advantage of intercropping. in this analysis, the ler values in all intercropping systems were greater than 1.0 (table 5) indicating the yield benefit of intercropping over sweet gourd single cropping. the results were consistent with the observations of seran and brintha (2009). system productivity index (spi): the findings revealed that 100% sweet gourd + 4 rows cauliflower (60 cm  50 cm) t4 intercropping system showed the maximum spi value (31.02) than other intercropping systems (table 5). the system productivity index (spi) assists in standardizing the yield of the secondary crop (cauliflower) in terms of the primary crop (sweet gourd), as well as identifying the crop combinations that most effectively used growth resources while maintaining consistent yields. (tajudeen, 2010). replacement value of intercropping (rvi): the rvi values were in the range of 2.03 to 2.32. the rvi value for sole sweet gourd (t1) was the lowest (1.68). the greatest rvi value (2.32) was found in t4 (100% sweet gourd + 4 rows cauliflower (60 cm  50 cm) (table 5), suggesting that this combination was more lucrative than sweet gourd alone and other intercropping treatments. it was found that about 50% more lucrative than sole sweet gourd crop was intercropping cauliflower with sweet gourd. monetary advantage index (mai): the monetary advantage index (mai) values were positive in all intercropping treatments (table 5). the highest mai (tk. 79907 ha-1) was received in t4 (100% sweet gourd + 4 rows cauliflower (60 cm  50 cm) which implies that this combination was productive and financially beneficial due to higher ler value. table 5. land equivalent ratio (ler), system productivity index (spi), replacement value of intercropping (rvi) and monetary advantage index (mai) of sweet gourd with cauliflower intercropping system (average of 2 years) treatments ler values spi rvi mai (tk. ha-1) sweet gourd cauliflower total t1 1.00 1.00 1.68 t2 0.79 0.48 1.28 27.94 2.12 55908 t3 0.87 0.34 1.21 25.90 2.03 43692 t4 0.79 0.60 1.40 31.02 2.32 79907 t5 0.80 0.43 1.24 26.91 2.06 48454 t6 0.79 0.46 1.26 27.42 2.09 52076 t7 1.00 1.00 t1=sole sweet gourd (2m × 2m), t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm × 80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm), t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm) and t6=100% sweet gourd+5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm) competitive ratio (cr): the competitive ratio values showed difference between the intercropping treatments suggesting the differential competitive potential of the component crop to be affected by the intercrops of cauliflower (table 6). cauliflower had a higher cr value (range: 1.30-2.56) than sweet gourd (range: 0.39-0.76), suggesting that cauliflower was the excellent competitor relative to sweet gourd. as a result, 100% sweet gourd + 3 rows cauliflower (60 cm  80 cm) (t2) intercropping system with higher cr discrepancy (2.17) showed differentials in the competitiveness of the component crops. however, 100% sweet gourd + 4 rows of cauliflower (50 cm  50 cm) (t4) 136 khanum et al. intercropping system with a lower cr discrepancy (0.54) showed quite meaningful competition between component crops. the findings revealed that equal competition across component crops with a minimal cr allowed for more efficient use of growth resources, resulting in increased intercropping efficiency and production. these results are consistent with the observations of islam et al. (2016). relative crowding coefficient (rcc): the relative crowding coefficient (rcc) of sweet gourd and cauliflower was substantially higher than unity, indicating higher non-competitive interference than competitive interference. i.e., yield benefits were received in intercropping treatments where t4 treatment was the maximum (5.94). in all treatments, the intercropped sweet gourd had greater relative crowding coefficient values, that seems to be, more aggressive than the intercropped cauliflower (table 5). table 6. competitive ratio (cr) of sweet gourd and cauliflower in sweet gourd-cauliflower intercropping system (average 2 years) treatments competitive ratio (cr) relative crowding coefficient (rcc) sweet gourd cauliflower differences sweet gourd cauliflower product t1 t2 0.61 1.63 1.02 1.45 2.53 3.67 t3 0.39 2.56 2.17 1.63 2.25 3.66 t4 0.76 1.30 0.54 1.91 3.11 5.94 t5 0.54 1.85 1.31 1.29 2.49 3.21 t6 0.57 1.73 1.16 1.23 2.76 3.39 t7 t1=sole sweet gourd (2m  2m), t2=100% sweet gourd+3 rows cauliflower 37.5% (60 cm  50 cm), t3=100% sweet gourd+3 rows cauliflower 23% (60 cm  80 cm), t4=100% sweet gourd+4 rows cauliflower 50% (50 cm  50 cm), t5=100% sweet gourd+4 rows cauliflower 31% (50 cm  80 cm) and t6=100% sweet gourd+5 rows cauliflower 31% (40 cm  100 cm) and t7=sole cauliflower (50 cm  50 cm) conclusion intercropping not only enhances productivity and system sustainability but also enhances farmer’s income, employment and reduces risks against climatic aberrations and changes. sweet gourd 100% (2m × 2m) + 4 rows cauliflower 50% (50 cm × 50 cm) combinations could be productive and profitable for cauliflower intercropping with sweet gourd. references ali, m. and j.s. mishra. 1993. intercropping of black gram (phaseolus mungo) and green gram (p. radiatus) with spring sunflower (helianthus annuus). indian j. agric. sci. 63: 493-495. alizadeh, y., a. koocheki and m.n. mahallati. 2010. yield, yield components and potential weed control of intercropping bean (phaseolus vulgaris l.) with sweet basil (ocimum basilicum l.). iranian j. field crops res. 7(2): 541-553. awal, m.a., h. koshi and t. ikeda. 2006. radiation interception and use by maize/peanut intercrop canopy. agricultural and forest meteorology. 139: 74-83. banik, p., a. midya, b.k. sarkar and s.s. ghose. 2006. wheat and chickpea intercropping systems in an additive series experiment: advantages and weed smothering. european j. agron. 24: 325-332. bbs. 1990-2017. yearbook of agricultural statistics of bangladesh, bangladesh bureau of statistics, statistical division, ministry of planning, government of the people's republic of bangladesh, dhaka. intercropping cauliflower with sweet gourd 137 bharati, v., r. nandan, v. kumar and i.b. panday. 2007. effect of irrigation levels on yield, water-useefficiency and economics of winter maize (zea mays)-based intercropping systems. indian j. agron. 52(1): 27-30. fao. 2015. statistical yearbook 2013/2014, vol. 2, fao. rome. retrieval from www.fao.org. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council. new airport road, farmgate, dhaka. pp.95-106. ghosh, p.k. 2004. growth, yield, competition and economics of groundnut/cereal fodder intercropping systems in the semi-arid tropics of india. field crops res. 88: 227-237. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley and sons, new york. pp.97-129. hossain, m.h., s.k. bhowal and a.s.m.m.r. khan. 2015. intercropping system of maize with different winter vegetables. malays. j. med. biol. res. 2(2): 153-156. islam, m.n., m. akhteruzzaman and m.s. alom. 2013. split application of inorganic fertilizers in potato (solanum tuberosum l.)-hybrid maize (zea mays l.) intercropping system. bangladesh j. agril. res. 38(3): 447-453. islam, m.r., m.s.m. molla and m.a.k. main. 2016. productivity and profitability of intercropping sesame with turmeric at marginal farmers level of bangladesh. saarc j. agril. 14(1): 47-58. khan, m., n. sultana, n. akter, m. zaman and m. islam. 2018. intercropping garden pea (pisum sativum) with maize (zea mays) at farmers’ field. bangladesh j. agric. res. 43: 691-702. khanum, m.m., m.m. bazzaz, b. ahmed, m.s. huda, m.a. hossain. 2019. intercropping of cabbage with maize, bangladesh agron. j. 22(1): 115-120. moseley, w.g. 1994. an equation for the replacement value of agroforestry. agrofor. sys. 26: 47-52. ofori, f. and w.r. stern. 1987. cereal-legume intercropping systems. adv. agro. 41: 41-90. rahman, m., s. roy, m. ahmed and m. bhuyan. 2015. on-farm study on intercropping of hybrid maize with different short duration vegetables in the char land of tangail. bangladesh agron. j. 18: 6569. santalla, m., a.p. rodino, p.a. casquer and a.m. de ron. 2001. interactions of bush bean intercropped with field and sweet maize. european j. agron. 15: 185-196. seran, t.h. and i. brintha. 2009. studies on determining a suitable pattern of capsicum (capsicum annum l.) vegetable cowpea (vigna unguiculata l.) intercropping. karnataka j. agric. sci. 22: 11531154. tajudeen, o.o. 2010. evaluation of sorghum-cowpea intercrops productivity in savanna agro-ecology using competition indices. j. agric. sci. 2: 229-234. willey, r.w. 1979. intercropping its importance and research needs. part. 1. competition and yield advantages. field crops abst. 32(1): 1-10. willey, r.w. and r.m. rao. 1980. a competitive ratio for quantifying competition between intercropping. expt. agric. l6: 117-125. http://www.fao.org/ bangladesh agron. j. 2021, 24(1): 71-81 effects of irrigation, organic and inorganic nutrient sources on the growth, yield and soil fertility status with rice-rice cropping m.a. khan1, s.a. shampa1, p.k. biswas2 and m.b. hossain3 1department of soil science, 2department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 3bangladesh agricultural research council, farmgate, dhaka-1207, bangladesh corresponding e-mail: makhan_sau@ymail.com (received: 07 march 2021, accepted: 26 march 2021) keywords: irrigation, fertilizer, manure, rice yield, soil fertility abstract continuous cultivation of highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (som) content. the experiment was laid out inasplitplot design with irrigation (i1: traditional irrigation i.e. continuous flooding, i2: saturated condition, i3: alternate wetting and drying) in main plots and fertilizers treatments: t0 = control, t1 =100% (recommended dose of chemical fertilizer), t2 =50% rdcf + 5 ton cowdung ha1, t3=70% rdcf + 3 ton cowdung ha-1, t4 =50% rdcf + 5 ton compost ha-1, t5 =70% rdcf + 3 ton compost ha-1, t6 = 50% rdcf + 3.5 ton poultry manure ha-1, t7 =70% rdcf + 2.1 ton poultry manure ha-1to the sub plots. the rice yields were not significantly affected by different irrigation but higher grain yields were obtained in continuous flooded irrigation. the treatment t7 gave higher boro and t. aman rice yields. the higher boro rice grain yields were obtained from i1t7 (70% rdcf + 2.1 ton poultry manure ha-1 with continuous flooded irrigation) followed by i3t7 (alternate wetting and drying + 70% rdcf + 2.1 ton poultry manure ha-1). the 100% rdcf was applied to t. aman rice resulted residual effects of fertilizer and the higher t. aman rice yields were recorded in i2t2 (saturated condition + 50% rdcf + 3 ton cowdungha-1) followed by i2t3 (saturated condition + 50% rdcf + 3 ton cowdungha-1) treatment combinations due to more residual effects of inorganic plus manure application during boro rice cropping. the highest organic matter level was found in post-harvest soils where inorganic fertilizer plus cowdung were used and soil ph increased by using poultry manure. the higher levels of available p and k concentrations were observed in the post experiment soils where fertilizer and manure were applied. introduction rice-rice is the most important cropping system in bangladesh. continuous cultivation of this highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (som) content. organic matter decomposition, nutrient mineralization, leaching and efficiency of fertilizer and manures in rice field are greatly affected by the soil moisture level. the yield of rice is low in bangladesh than in the other rice growing countries like south korea and japan (fao, 1999). organic and chemical fertilizers are applied for higher yield and improvement of soil fertility and physico-chemical properties. more nutrients are leached out from soil when more 72 khan et al. irrigation water is added during boro rice growing period. moisture levels affect the organic matter accumulation and mineralization. yang et al. (2004) reported that application of chemical fertilizers with farmyard manure or wheat or rice straw in alternate wetting and drying condition increased n, p, & k uptake by rice plants. organic manure can supply a good amount of plant nutrients thus can contribute to crop yields. the integrated approach by using the organic and inorganic sources of nutrients helps to improve the efficiency of nutrients. water input can be reduced by reducing ponded water depths to soil saturation or by alternate wetting/drying. increasing water scarcity necessitates the development of irrigated rice systems that require less water than traditional flooded rice. in irrigated aerobic rice systems, rice grows in non-flooded and saturated irrigation. the present research work was, therefore, undertaken to find out the effect of chemical fertilizers and organic manure on the productivity and fertility and nutrient availability in boro-t. aman rice cropping pattern. materials and methods field characteristics the experiment was conducted in the field of experimental farm at sher-e-bangla agricultural university (sau), dhaka during january, 2012 to december, 2014. the area belongs to the tejgaon soil series of madhupur tract (aez 28) having 2874n latitude and 9035 e longitude with an elevation of 8.2 meter from sea level. the soil of the experimental field classified as deep red brown terrace soils in bangladesh soil classification system (undp and fao, 1988). the soil is a silt loam with 6.4 ph, 1.12% organic matter (walkley and black, 1975), 0.08% total n (micro kjeldahl method; bremner and mulvaney, 1982), 12.0 μg g-1 available p (0.5m nahco3 extractable; olsen and sommers, 1982) and 22.5 μg g-1 exchangeable k (1mnh4oac extractable; page et al., 1982). experimental design and treatment the experiment was laid out in a split plot design assigning irrigations to the main plots and fertilizer treatments to the sub-plots with three replications. three irrigation treatments (i1= continuous flooding (3-4 cm water), i2= saturated condition (disappearance of water on the surface) and i3: alternate wetting and drying) and eight fertilizer treatments t0: control, t1: 100% recommended dose of chemical fertilizer (rdcf), t2: 50% rdcf + 5 tha-1 cowdung, t3: 70% rdcf + 3 tha-1 cowdung, t4: 50% rdcf + 5 tha-1compost, t5: 70% rdcf + 3 tha-1 compost, t6: 50% rdcf + 3.5 tha-1 poultry manure, t7: 70% rdcf + 2.1 tha-1 poultry manure were applied in the experiment during boro rice cultivation. field experiment the land was leveled and the experimental plot was partitioned into the unit plots. treatment wise cowdung, compost, and poultry manures were applied before four days of final land preparation. there were 1.46% n, 0.29% p, 0.74% k in cowdung; 2.2% n, 1.99% p, 0.82% k in poultry manure and 1.49% n, 0.28% p, 1.60% in water hyacinth compost. tsp, mop, gypsum, zinc sulphate and one third urea were applied during final land preparation. the remaining one third urea was applied at 30 dat and another one third at 55 dat. the fertilizer and manures were mixed in the soils of the plots. the first crop boro rice var. brri dhan29 was transplanted during first week of january, 2012 and second crop t. aman rice (var. brri dhan32) was transplanted in july 2012. the 35-day old seedlings for boro rice (dry season rice) and t. aman (wet season rice) were transplanted with a spacing of 20 cm × 20 cm. intercultural operations were done whenever required. effects of irrigation and nutrient sources on rice-rice cropping pattern 73 after harvest of boro rice, t. aman rice was transplanted and grown in rainfed condition without any manure application in soil but recommended dose (n100p15k45s12zn2) was applied. supplemented irrigation was applied as per irrigation treatments during t. aman growing period. the yield and yield parameters were recorded for each crop. similarly, third crop boro rice (2013), fourth crop t. aman rice (2013) and fifth crop boro rice (2014) were grown in the same plots with the application of similar fertilizer and irrigation treatments. after harvest of fifth crop, treatment wise postexperimental soils were collected from 0-15cm depth and analyzed for n, p, k, ph and soil organic matter content by using standard methods. soil analysis: soil ph was measured by glass electrode ph meter using soil-water ratio 1:2.5 (mclean, 1982). organic matter content was estimated by wet oxidation method (walkley and black, 1975). the total n contents in soil were determined by micro-kjeldahl method (bramner and mulvaney, 1982). the soil p (olsen and sommers, 1982) and k (page et al.,1982) were determined by using spectrophotometer and flame photometer, respectively. statistical analysis the data obtained for different parameters were statistically analyzed and significance of the difference among the treatment means was estimated by the duncan’s multiple range test (dmrt) at 5% level of probability. results and discussion effects of irrigation, fertilizer and manure (boro rice) the number of effective tillers hill-1 was significantly influenced by irrigation in first crop boro rice and the highest number of effective tillers hill-1 was found in continuous flooded condition (i1) and lowest in i3 (alternate wetting and drying) (table 1). higher yields of first and third boro rice crops were found in continuous flooded condition which was closely similar to other irrigation treatments (table 1). table 1. effects of irrigation on the effective tillers hill-1, grain and straw yield of first (boro), second (t. aman) and third (boro) rice crops treatments number of effective tillers hill-1 straw yield (t ha-1) grain yield (t ha-1) 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop i1 13.8a 7.15 12.52 7.07 5.98 7.02 7.06 4.37 6.38 i2 11.3b 7.27 12.89 7.08 6.53 6.81 6.94 4.81 6.05 i3 12.6ab 6.94 13.03 6.82 6.52 6.81 6.82 4.58 6.19 i1=continuous flooded; i2= saturated condition; i3= alternate wetting and drying in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt among the different fertilizer treatments, t3 showed maximum number of effective tillers hill-1 (13.9) in first crop boro rice which was statistically similar to t7 (70% rdcf + 2.1 ton poultry manure ha-1) treatment. in first crop, t7 showed the maximum plant height (89.67 cm) which was statistically similar to all other treatments except t0 (control). in second crop (t. aman rice), the residual effect of t7 and renewal application of chemical fertilizer showed the highest number (7.6) of effective tillers hill-1. treatment t4 followed by t3 showed the maximum plant height (124.9 cm) and panicle length (26.06 cm) which was statistically similar to all fertilizer 74 khan et al. treatments except t0. in the third crop boro rice, the highest number of effective tillers hill-1 (14.1) was found in t7 treatment and higher plant height, panicle lengths and number of filled grains panicle-1 were found in organic plus inorganic treatments (table 2). the lowest number of effective tillers hill-1, plant height, and filled grains panicle-1 were observed in t0 treatment. different fertilizer treatments showed significant variations in respect of grain and straw yields in first, second and third rice crops (table 3). the highest straw yield of first crop was obtained in t3 treatment which was statistically similar to t4, t5 and t7and the lowest straw yield was obtained in t0 treatment. the highest grain yield (7.47 t ha-1) of first crop was observed in the t7 treatment which was statistically similar with the t1, t3, t4 and t5 and the lowest grain yield (5.02 t ha-1) was observed with t0 treatment. the highest straw yield of second crop (6.78 t ha-1) was obtained in t2 treatment which was statistically similar to all other treatments except t0. the highest grain yield of second crop was observed in the t7 treatment which was statistically similar to all other treatment except t0 (control and the lowest grain yield (3.79 tha-1) was observed with t0 where no fertilizer was applied. the highest straw yield of third crop (7.72 t ha-1) was obtained in t1 (100% rdcf) treatment which was statistically similar to t3, t5. t6 and t7 treatments and the lowest straw yield was obtained in t0treatment. the highest grain yield of third crop was observed in the t1 and t7 treatments and the lowest grain yield (5.02 t ha-1) was observed with t0 where no fertilizer was applied. table 2. effects of nutrient sources on the effective tillers, plant height and panicle length of first (boro), second (t. aman) and third (boro) rice crops treatments number of effective tillers hill-1 plant height (cm) panicle length (cm) 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop 2nd crop 3rd crop t0 11.8c 6.77 10.53c 77.89b 105.79b 73.02b 23.36b 22.47c t1 13.6ab 7.31 13.87a 89.33a 123.34a 85.57a 24.70ab 25.04ab t2 12.3abc 6.76 11.13bc 85.55a 124.44a 86.46a 26.51a 24.57ab t3 13.9a 7.27 13.22a 87.55a 122.65a 86.57a 26.06a 24.74ab t4 12.8abc 7.36 12.73ab 86.88a 124.99a 84.20a 25.55a 24.75ab t5 11.6c 6.64 13.22a 87.33a 123.36a 84.83a 25.31ab 25.68a t6 12.0bc 7.31 13.73a 86.44a 121.15a 87.55a 25.16ab 24.41b t7 12.4abc 7.56 14.07a 89.67a 124.80a 84.53a 25.24ab 24.84ab in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt table 3. effects of nutrient sources on the filled grains panicle-1, grain and straw yield of first (boro), second (t. aman) and third (boro) rice crops treatments filled grains panicle-1 straw yield(t ha-1) grain yield(t ha-1) 1st crop 3rd crop 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop t0 99.7b 83b 5.63 c 5.201b 4.03c 5.02 c 3.79b 3.47d t1 130.6a 107a 7.01 b 6.71a 7.72a 7.40 a 4.81a 7.01a t2 108.0a 129a 7.01 b 6.78a 6.91b 6.86 b 4.71a 6.40abc t3 122.7a 113a 7.55 a 6.10ab 7.48ab 7.41 a 4.56a 6.91ab t4 123.3a 121a 7.23 ab 6.29ab 6.81b 7.19 ab 4.48a 6.21c t5 122.3a 116a 7.14 ab 6.65a 7.23ab 7.24 ab 4.50a 6.32bc t6 114.2a 129a 7.01 b 6.55a 7.61a 6.95 b 4.85a 6.78abc t7 109.1a 121a 7.36ab 6.48a 7.25ab 7.47 a 4.98a 7.01a in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt effects of irrigation and nutrient sources on rice-rice cropping pattern 75 interaction effects of irrigation and fertilizer the highest grain yield of first crop boro rice (7.93 t ha-1) was recorded with the treatment combination i1t7 which was statistically similar to i1t2, i1t3, i2t5, i2t3, i2t4, i2t5, i3t3 i3t5 and i3t5 treatment combinations and the lowest grain yield (4.48 t ha-1) was found in i3t0 treatment (table 4). the highest grain yield of second (5.34 t ha-1) and third crops (7.36 t ha-1) were found in i2t7 and i2t7 treatment combinations, respectively. these results indicate that 70% nutrient from inorganic fertilizer and 30% nutrient from poultry manure or cowdung or compost with continuous flooding or saturated condition or alternate wetting drying performed better for increasing the yield of boro rice and similar results in the second crop t. aman rice due to the combined application manure and fertilizer. among the manure poultry manure performed better with different levels irrigation. table 4. interaction effect of fertilizer and irrigation on the grain and straw yields of first (boro rice), second crop (t. aman rice) and third crop (boro rice) treat. ist crop 2nd crop 3rd crop grain yield (t ha-1) i1 i2 i3 i1 i2 i3 i1 i2 i3 t0 4.91e 5.66d 4.48e 3.71 3.86 3.81 3.43 3.48 3.51 t1 7.51ab 7.53ab 7.15b 4.96 5.24 4.23 6.86 7.26 7.03 t2 7.32ab 6.37c 6.90bc 4.66 4.89 4.59 6.78 5.82 6.60 t3 7.32ab 7.42ab 7.50ab 4.25 4.46 4.97 7.29 6.69 6.75 t4 7.30ab 7.27ab 7.00bc 4.19 4.46 4.78 6.55 6.40 5.67 t5 7.18b 7.32ab 7.21ab 4.01 4.96 4.52 6.31 6.30 6.35 t6 7.04bc 6.90bc 6.91bc 4.16 5.23 5.15 6.53 6.36 6.23 t7 7.93a 7.08bc 7.40ab 5.04 5.34 4.55 7.31 6.06 7.36 straw yield (t ha-1) t0 5.57 6.33 4.97 5.00 5.15 5.46 5.57 6.33 4.97 t1 7.37 6.94 6.71 6.75 6.78 6.59 7.37 6.94 6.71 t2 7.23 6.70 7.10 5.56 7.00 7.35 7.23 6.70 7.10 t3 7.32 7.74 7.58 5.78 6.23 6.28 7.32 7.74 7.58 t4 7.27 7.18 7.24 6.01 6.24 6.61 7.27 7.18 7.24 t5 7.08 7.18 7.15 6.23 6.55 7.17 7.08 7.18 7.15 t6 7.04 7.13 6.88 6.19 6.86 6.58 7.04 7.13 6.88 t7 7.65 7.46 6.96 6.32 7.40 6.10 7.65 7.46 6.96 in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt the combined effects of different doses of fertilizer and irrigation on the grain and straw yield of rice were not significantly different. the 100% rdcf was applied in all the treatments during t. aman rice cultivation except control treatment but yields were significantly affected due to the application of different types of fertilizer and manure treatments in the previous boro rice cultivation. higher t. aman rice yields (second crop) were obtained in organic plus inorganic fertilizer treatments with different levels of irrigation due to residual effects of fertilizer and manure which was applied in previous boro rice cultivation. the highest straw yield (7.74 t ha-1) of third crop was obtained from i2t3 treatment combination. the highest grain yield of third crop (7.36 t ha-1) was recorded with the treatment combination i3t7 which was similar to i1t7 (7.31 t ha-1), i1t3 (7.29 t ha-1) and i2t1 (7.26 t ha-1) 76 khan et al. treatment combinations. the lowest grain yield (3.43 t ha-1) was found in i1t0 treatment combination. this result indicated that 70% nutrient from inorganic source and 30% nutrient from poultry manure with the application of alternate wetting and drying performed better for increasing the boro rice yield. rahman et al. (2019) and islam et al. (2013) found similar results by using manure and fertilizer in rice with different levels of irrigation. effects of irrigation, fertilizer and manure on the growth and yield of fourth crop t. aman rice the results showed that the yield and yield parameters of t. aman rice were not significantly influenced by irrigation but significantly influenced by residual effects of fertilizer and manure application (table 5). among the different fertilizer treatments, t6 showed the highest plant height (123.2 cm). the maximum panicle length (25.26 cm), filled grains panicle-1 (88.1) and 1000 seed weight (21.22 g) were found in the t5, t3 and t7 treatments respectively and the lowest plant height, number of effective tillers hill-1, filled grains panicle-1were observed in t0 treatment. the application of fertilizers plus manure in the previous rice crops had a positive and significant effect on the grain and straw yield of t. aman rice (table 5). the highest straw yield (6.26 t ha-1) was obtained due to the residual effect of t5 treatment which was statistically similar to all other treatments except t0. table 5. effect of fertilizer and manure on the yield parameters and yield of fourth crop t. aman rice treatments plant height (cm) panicle length (cm) number of filled grains panicle-1 1000grainweight(g) straw yield (t ha-1) grain yield (t ha-1) t0 104.9b 21.78c 68.37b 19.56c 4.42b 3.47b t1 118.6a 24.46ab 85.42a 20.78ab 6.03a 4.34a t2 120.7a 24.46ab 87.93a 20.22bc 5.78a 4.48a t3 120.8a 24.77ab 88.09a 20.44abc 6.02a 4.40a t4 119.9a 23.99b 83.69a 21.11ab 5.94a 4.32a t5 118.9a 25.26a 84.71a 21.00ab 6.26a 4.09a t6 123.2a 24.29b 84.77a 20.89ab 5.82a 4.07a t7 119.3a 24.36ab 78.84a 21.22a 5.92a 4.18a in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt the highest grain yield (4.48 t ha-1) was observed in the t2 treatment in boro rice crops which was statistically similar to all other treatment except t0 (control). this result indicates that t. aman rice yield was increased more due to the residual effects of fertilizer plus manure treatments which were applied during previous boro rice cropping. the lowest grain yield (3.79 t ha-1) was observed with t0 where no fertilizer was applied. interaction effects of fertilizer and manure on the grain and straw yield of fourth crop t. aman rice plant height, panicle length, number of filled grains panicle-1, 1000 seed weight were not significantly influenced by interaction effect of irrigation and fertilizer. the grain and straw yields were significantly influenced by irrigation and fertilizer treatments. the highest straw yield (7.21 t ha-1) was found in i1t5 treatment combination which was statistically similar to i1t7, i2t1, i2t2, effects of irrigation and nutrient sources on rice-rice cropping pattern 77 i2t3 treatment combinations. the highest grain yield of 5.35 t ha-1 was recorded in i2t2 treatment combination which was statistically comparable to i1t5, i1t7, i2t1, i2t3 and i3t4. table 6. effect of irrigation and fertilizer and manure on the grain and straw yield of fourth crop (t. aman rice ) treat. grain yield (t ha-1) straw yield (t ha-1) i1 i2 i3 i1 i2 i3 t0 3.35h 3.58fgh 3.47gh 4.45fg 4.65efg 4.16g t1 3.96d-h 4.87abc 4.21c-g 5.71b-f 6.65a-d 5.75a-f t2 3.97d-h 5.35a 4.13c-h 5.28c-g 6.88ab 5.20d-g t3 3.80d-h 5.09ab 4.31b-f 5.51b-g 6.70abc 5.84a-f t4 4.37b-f 4.02d-h 4.56a-d 5.61b-g 5.79a-e 6.42a-d t5 4.84abc 3.67e-h 3.77d-h 7.21a 5.90a-e 5.67b-f t6 3.90d-h 3.91d-h 4.42b-e 5.34c-g 6.13a-d 6.00a-e t7 4.56a-d 4.11c-h 3.89d-h 6.72abc 5.63b-f 5.42b-g in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt these results indicate that t. aman rice yield was increased due to the interaction of effects of fertilizer and reduced irrigation treatments where fertilizer, manure were applied combined with reduced level of irrigation during previous boro rice cropping (table 6). individual effects of irrigation and fertilizer on growth, yield of fifth crop boro rice the number of effective tillers hill-1, plant height, filled grains panicle-1, grain yield were not significantly affected by irrigation but panicle length and straw yields were affected significantly (table 7). the highest number of effective tillers hill-1 (13.64), were found in continuous flooded condition which was closely similar to (13.58) in alternate wetting and drying irrigation. the highest panicle length (22.29 cm) and straw yield (7.51 t ha-1) were found in i1 and lower and statistically similar panicle length and straw yield were recorded in i2 and i3 treatments. the highest grain yield (7.11 t ha-1) was found in i1treatment which was closely similar to saturated irrigation (6.98 t ha-1) and the lowest (6.87 t ha-1) in i3. table 7. effect of irrigation on the growth and yield parameter of fifth crop boro rice treatments number of effective tillershill-1 plant height (cm) panicle length (cm) number of filled grainspanicle-1 straw yield (t ha-1) grain yield (t ha-1) i1 13.64 77.40 22.29b 93.48 7.51b 7.11 i2 13.18 76.82 21.62a 98.23 7.22a 6.98 i3 13.58 76.36 21.75a 98.42 7.24a 6.87 i1=continuous flooded; i2= saturated condition; i3= alternate wetting and drying in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt 78 khan et al. the number of effective tillers hill-1, panicle length, filled grains panicle-1, straw and grain yield were significantly affected by application of different fertilizer and manure (table 8). the highest number of effective tillers hill-1 (14.4) was found in t1 treatment which was statistically similar to all other treatments except t0 (control). the higher plant height, panicle lengths, filled grains panicle-1 were found in organic plus inorganic treatments and lowest values were observed in t0 treatment. the highest panicle length (22.50 cm), filled grains panicle-1 (108.5) were found in t6 where filled grains panicle-1 was statistically similar to t4, t7, t3, t5 and t1 treatments. table 8. effects of fertilizer and manure on the yield parameters and yield of fifth crop boro rice treatments no. effective tillers hill-1 plant height (cm) panicle length (cm) no. of filled grains panicle-1 straw yield (t ha-1) grain yield (t ha-1) t0 10.80b 70.91 20.53b 78.3c 5.70.b 5.42e t1 14.36a 78.31 22.30a 94.4abc 7.78a 7.03cd t2 14.09a 78.37 22.28a 90.1bc 7.39a 7.07bcd t3 13.53a 76.13 21.64ab 100.8ab 7.66a 7.37abc t4 13.40a 76.69 21.95a 103.2ab 7.35a 7.19bc t5 14.07a 79.02 22.01a 95.7abc 7.48a 6.74d t6 13.62a 78.21 22.50a 108.5a 7.49a 7.40ab t7 13.87a 77.22 21.87a 102.5ab 7.71a 7.70a in a column figures having similar letter(s) do not differ significantly at 5% level whereas figures with dissimilar letter(s) differ significantly as per dmrt the application of fertilizers and manure had a positive and significant effect on the grain and straw yield of boro rice (table 8). the highest straw yield (7.78 t ha-1) was obtained in t1 (rdcf) treatment which was statistically similar to all other treatments except control. the highest grain yield (7.70 t ha-1) was observed in the t7 treatment which was statistically similar to t6 treatments and lowest grain yield (5.02 t ha-1) was observed in t0 treatment. this result indicates that application of 70% nutrient as inorganic fertilizer and 30% nutrient from organic sources increased the yield and yield contributing parameters of boro rice. interaction effects of irrigation and fertilizer on the growth and yield of fifth crop boro rice the numbers of effective tillers hill-1, panicle length and straw yield were not significantly influenced by combined effects of irrigation and fertilizer. the maximum plant height (81.60 cm) and filled grains panicle-1 (119.60 cm) were obtained from i1t3 which was closely similar to i1t7, i3t6, i3t7 and lowest was recorded in i1t0 treatment combination (table 9). the highest grain yield of rice (7.94 t ha-1) was recorded with the treatment combination i1t7 which was statistically similar to i1t3 (7.73 t ha-1), i1t6(7.72 t ha-1), i3t7(7.62 t ha-1), i1t4(7.60 t ha-1) and i3t6(7.55 t ha-1) treatment combinations and the lowest grain yield (5.26 t ha-1) was found in i2t0 treatment combination. the results also indicate that 70% nutrient from inorganic sources plus 30% nutrient from poultry manure or cowdung with continuous flooded (i1) or alternate wetting and drying (i3) condition produced better yield of boro rice. the best yield performance was obtained from i1t7 treatment combinations followed by i1t3. lin et al. (2011) reported that reduced irrigation with organic material application increased yield of rice. effects of irrigation and nutrient sources on rice-rice cropping pattern 79 table 9. interaction effect of fertilizer and irrigation on plant height, filled grains/panicle and grain yield of fifth crop boro rice treat. plant height (cm) no. of filled grains panicle-1 grain yield (t ha-1) i1 i2 i3 i1 i2 i3 i1 i2 i3 t0 69.73h 72.43fgh 70.58gh 70.4g 80.8efg 83.8c-g 5.60i 5.26i 5.38i t1 78.78a-d 77.63a-e 78.53a-d 74.3fg 111.4a-d 97.6a-g 6.71gh 7.50a-e 6.87fgh t2 77.60a-e 77.62a-e 79.88abc 82.6d-g 85.1b-g 102.7a-f 7.08c-h 6.99d-h 7.15b-h t3 81.60a 74.20d-h 72.58e-h 119.6a 97.8a-g 85.1b-g 7.73ab 7.16b-g 7.22b-g t4 77.62a-e 77.31a-f 75.16c-g 96.5a-g 112.8abc 100.4a-f 7.60abc 7.40a-f 6.56h t5 79.43abc 81.60a 75.96b-f 86.1b-g 103.8a-f 97.4a-g 5.77i 7.14b-h 7.30b-g t6 75.98b-f 77.87a-d 80.78ab 108.0a-e 103.8a-f 113.7ab 7.72ab 6.93e-h 7.55a-d t7 78.47a-d 75.83b-f 77.36a-f 110.5a-e 90.3a-g 106.6a-e 7.94g 7.53a-d 7.62abc in a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per dmrt effect of irrigation, fertilizer and manure on the nutrient concentration and chemical properties of post-harvest field soil the application of manure and fertilizer in the boro seasons influenced the om content in soil. the lower level of om matter was found in the post-harvest soils of t0 (control) and t1 (rdcf) treatments. the increasing levels of om were almost similar in all the treatments where manure plus inorganic fertilizer were used. similarly, higher levels of available p were found in the t2-t7 treatments where organic plus inorganic fertilizers were used. the highest concentration p was found in the t7 treatment where 70% rdcf + 2.1 ton poultry manure ha-1 used. the level of soil n and k concentrations were increased more where inorganic and organic fertilizers were used. the highest k concentration was found in t5 treatment where 70% inorganic fertilizer and 3 ton ha-1 water hyacinth compost were used. the ph of post-harvest soils increased in t6 and t7 treatments where poultry manure was applied in combination with fertilizer (table 10). the soil organic matter, ph and nutrient levels were not significantly affected by interaction effects of irrigation and fertilizer treatments. table 10. effect of fertilizer and manure on the nutrient concentration and chemical properties of post-experiment soil treatments soil ph soil organic matter (%) total n (%) available p (ppm) available k (ppm) t0 6.6b 1.08c 0.079 11.23d 19.56c t1 6.6b 1.15bc 0.088 13.62c 28.33ab t2 6.6b 1.33a 0.096 15.80abc 29.44ab t3 6.6b 1.32a 0.096 13.82c 27.33b t4 6.6b 1.29a 0.092 14.26bc 30.11ab t5 6.5b 1.33a 0.102 15.21abc 31.94a t6 6.9a 1.31a 0.089 16.50ab 28.44ab t7 6.7ab 1.27ab 0.090 16.59a 29.61ab conclusion the growth and yield of rice crops were not significantly affected by irrigation but higher yields were obtained in continuous flooded irrigation. the higher boro rice yields were found from the treatments where 70% nutrient from inorganic fertilizer and 30% nutrients from organic sources 80 khan et al. were applied. the poultry manure performed better compared to compost and cowdung for increasing the yield of boro rice. the maxinum grain yield of boro rice was recorded with the treatment combination i1t7 (continuous flooding +70% rdcf + 2.1 ton poultry manure ha-1) followed by i3t7 (alternate wetting and drying + 70% rdcf + 2.1 ton poultry manure ha-1) treatment combination. t. aman rice yields were significantly influenced due to the residual effects of applied fertilizer plus manure treatments during previous boro cropping. higher t. aman rice yields were obtained in i2t7 (saturated condition +70% rdcf + 2.1 ton poultry manure ha-1) or i1t7 (continuous flooded + 70% rdcf + 2.1 ton poultry manure ha-1) treatment combinations. the level of soil organic matter, n, p and k concentrations increased in the treatments where manure plus inorganic fertilizers were used. the application of poultry manure increased the ph of the soil. acknowledgement the authors gratefully acknowledge the financial support from core research grants of bangladesh agricultural research council. references bari, a.s.m.f., m.a. khan and s. sultana. 2013. effect of various inorganic fertilizer and manure applications with different water managements on yield and yield attributes of boro rice. j. expt. biosci. 4(2): 1-6. bremner, j.m. and c.s. mulvancy. 1982. in: a.l. page et al. (ed.) methods of soil analysis, part 2,23 amer. soc. agron. inc, madi, wis. fao (food and agriculture organization). 1999. yearbook of production, fao statistics division. pp.605-607. islam, m.m.a.f., m.a. khan and a.s.m.f. bari. 2013. effect of fertilizer and manure with different water management on the growth, yield and quality of boro rice. the agriculturist 11(2): 4451. ishaque, m., g.m. panaullah, n. bhuyian and p.k. saha. 1998. integrated nutrient management with inorganic fertilizer and green/organic manures for boro-t. aman rice cropping pattern. in proceedings “national workshop on integrated nutrient management for crop production and soil fertility” held on 24-25 march, 1998 at bari, gazipur, bangladesh. pp.111-114. mclean, e.o. 1982. soil ph and lime requirement. in: methods of soil analysis, part 2, chemical and microbiological properties, a. l. page,(eds.), amer. soc. of agro. inc., madison, wi, usa. pp.199-224. rahman, m.m., m.a. khan, a.k. paul and m.a. haque.2019. effect of fertilizer, manure and irrigation on nutrient availability in soil of boro rice field. euras. j. soil sci. 8(4):282-288. olsen, s.r. and l.e. sommers. 1982. in: a.l. page et al. (ed.) methods of soil analysis, part 2,2 amer. soc. of agron. inc, madi, wis. page, a.l., r.h. miller and d.r. keeney. 1982. methods of analysis part 2, chemical and microbiological properties, second edition american society of agronomy, inc., soil sci. soc. of amer. inc. madison, wisconsin, usa. pp.403-430. undp and fao. 1988. land resources appraisal of bangladesh for agricultural report no. 2. agro-ecological region of bangladesh. united nations development program in food and agriculture organization, 212-221. effects of irrigation and nutrient sources on rice-rice cropping pattern 81 walkley, a. and d.r. black. 1975. an examination of the digestion method for determining soil organic matter and proposed modification of the chronic acid titration method. soil sci. 37: 29-38. xiangin, l., d. zhu and xinjunlin. 2011. effects of water management and organic fertilization with sri crop practices on hybrid rice performance and rhizosphere dynamics. paddy water environ. 9: 33-39. xu, m.g., d.c. li, j.m. li, d.z. qin, yagikazuyuki and y. hosen. 2008. effects of organic manure application with chemical fertilizers or nutrient absorption and yield of rice in hunan of southern china. agric. sci. china 7(10): 1245-1252. yang, c.m., l. yang, y. yang and z. ouyang. 2004. rice root growth and nutrient uptake as influenced by organic manure in continuously and alternately flooded paddy soils. agric. water mng. 70(1): 67-81. bangladesh agron. j. 2020, 23(2): 23-34 planting time effect on quality seed production of three varieties of carrot (daucus carota l.) lutfunnahar 1 , m. f. hossain 2* , m. a. malek 3 , r. kamrunnahar 4 and j.hossain 5 1 upazilla agriculture officer, dae, gouripur, mymensingh 2 regional agricultural research station, bari, ishwardi, pabna 3senior instructor, agriculture training institute, ishwardi, pabna 4 upazilla agriculture officer, dae, atgharia, pabna 5 pulses research centre, bari, ishwardi, pabna corresponding author: farukgolap@gmail.com (received: 20 september, 2020, accepted: 29 november, 2020) keywords: carrot, germination, seed yield, variety, umbel abstract crop management like planting time is a crucial factor for maximizing yield especially for seed production. seed production of carrot is greatly influenced by temperature as it requires adequate periods of cool temperature (vernalization) for flowering and seed production. to find out optimum planting time of carrot steckling for quality seed production the experiment was conducted at the field laboratory of horticulture farm, bangladesh agricultural university, mymensingh during the period from october 2015 to may 2016.three planting time viz. 05 january, 15 january and 25 january on the seed production of three carrot varieties viz. ba (brasillia agroflora), pa (prima agroflora) and nk (new kuroda) which constituted 9 treatment combinations were included in the experiment. the experiment was laid out in randomized complete block design (rcbd) with three replications. planting time had significant effect on most of the parameters studied. the january 05 planting of steckling gave the highest seed yield (527.92 kg ha -1 ) and the lowest was in january 25 planting of steckling (314.75 kg ha -1 ). among the varieties ba gave the highest seed yield (448.73 kg ha -1 ) and the lowest yield for new kuroda (395.35 kgha -1 .) considering interaction of planting time and variety the highest seed yield (572.37 kg ha -1 ) was obtained from the treatment combination of early planting (05 january) with the variety of ba and the lowest (279.77 kg ha -1 ) was recorded from the late planting (25 january) in variety pa. hence, ba carrot variety planting on 5 january may be recommended for carrot seed production in mymensingh region in bangladesh. introduction carrot (daucus carota var. sativus) is a member of the family apiaceae (peirce, 1987) and considered to be native of mediterranean region (shinohara, 1984) and its cultivation as a crop also began in that region. carrot is one of the most ancient vegetables grown all over the temperate regions in spring, summer and autumn. but in tropical and sub-tropical countries, carrots are produced during winter. carrot is important for its high nutritional value and possible diversified used in making different palatable dishes and long-term storage. it contains appreciable amount of carotene (10 mg/100g), thiamin (0.04 mg/g) and riboflavin (0.05 mg/g) (sharfuddin and siddique, 1985), and it is an excellent source of iron, carbohydrate vitamin-b, vitamin-c and sugar. in carrot roots sucrose is most abundant with endogenous sugar contents, 10 times more than those of glucose and fructose. further, it has some important medicinal value. carrot roots play an important role to protect the blindness in children providing vitamin a. the area of carrot cultivation in bangladesh is 5085 acre with a total production of 19246 mt (bbs, 2020). carrot is grown in bangladesh during winter season. it usually requires 24 lutfunnahar et al. relatively low temperature for flowering. the climatic condition of bangladesh is not very suitable for the production of seeds of most of the high yielding exotic varieties. moreover, a number of popular exotic cultivars are hybrid varieties. consequently, it has become a regular task for the government and private seed supplying organizations of bangladesh to import the seeds of high yielding carrot verities from abroad every year. almost entire production of carrot in bangladesh is based upon imported seeds. the imported seeds are relatively expensive which are not always available in time for sowing. hence, cultivation of good quality carrot becomes an uncertainty every year. on the other hand, locally produced seeds cannot cope with the requirement. to boost up carrot production in the country timely supply of quality seed in desired quantity should be ensure, which is possible only by improving local seed production technology. time of planting is an important factor for the quality of carrot seed production. the proper planting time depends on the existing cropping pattern and prevailing environment. it is the key factor for successful carrot seed production. carrot is a biennial crop and it seed production is greatly influenced by temperature (bose and som, 1986). it requires adequate periods of cool temperature (vernalization) for flowering and seed production. carrots should have sufficient vegetative growth prior to cool temperature exposure as vernalization successfully induces flower formation. the variation in flowering characters among the sowing dates could probably be related to the level and activity of endogenous gibberellins, substances known to enhance flowering characters in low temperatures (rubatzky et al., 1999). cold temperature (4-10ºc) for 4 to 8 weeks to initiate flowers and produce seeds depending on the cultivar. elongation of inflorescence, flowering and seed development requires warm temperature. whereas seed maturity and harvesting needs dry weather. early planting causes winter killing or late season pest infestations. planting too late results in a lack of vernalization, this limits flowering and thus reduces seed yield. growers tend to manipulate planting time in order to obtain better growth, more flower formation and finally higher production of quality seed. similarly, variety is another important factor for seed production. in bangladesh, there is no recommended variety of carrot. most of the seed companies of the world produce carrot seeds to suit their own climatic conditions and if the seeds are used without adaptability test, the growers may face economic losses. in this case, varietal selection plays an important role in carrot seed production. there is a vast scope for increasing the yield of carrot per hectare by using seeds of high yielding variety. many countries have developed good quality high yielding varieties even through introduction. hence, the present study was undertaken to find out the optimum planting time of steckling and suitable variety for maximum seed production of carrot. materials and methods the present research work was conducted at the field laboratory of horticulture farm of bangladesh agricultural university, mymensingh during the period from october 2007 to may 2008. the experimental area is located at 24.6 o n and 90.5 o e latitude and at an altitude of 18 m from the sea level. the soil of the experimental area was sandy loam type and belonged to the old brahmaputra flood plain alluvial tract (undp, 1988). the analytical data of the soil sample collected from the experimental area were determined in the humboldt soil testing laboratory, department of soil science, bangladesh agricultural university, mymensingh. the soil texture was silt loam consists of sand-35.40%, silt-62.60% and clay-6.15%. the experimental site was medium high land and the chemical properties of soil was presented in table 1. the experimental area is situated in the sub-tropical zone, characterized by heavy rainfall during the months of april to september and scanty rainfall during october to march (anon, 1999). rabi season is characterized by low temperature but plenty of sunshine. the detailed metrological data in respect of air temperature, relative humidity, total rainfall and soil temperature recorded by the weather yard, department of irrigation and water management. bangladesh agricultural university, mymensingh during the period of study have been presented in figure 1. planting time effect on quality seed production of three varieties 25 the two-factor experiment was laid out in the randomized complete block design (rcbd) with three replications. each block was divided into nine unit plots each measuring 1.5 m  1.0 m. the block to block and plot to plot distances were 1 m and 50 cm respectively. in each block nine treatments were placed randomly. thus, there were 27 (9×3) unit plots altogether in the experiment. the experiment consists of two factors viz., factor a: three dates of transplanting of steckling, p1 = early planting (05 january 2016); p2 = mid planting (15 january 2016) and p3 = late planting (25 january 2016) and factor b: three varieties, v1 = brassilia agroflora (ba); v2 = prima agroflora (pa) and v3 = new kuroda (nk). ploughing and cross ploughing by power tiller was done followed by laddering to obtain a good tilth condition. the land was fertilized cow dung, urea, tsp (triple super phosphate) and mop (muriate of potash) were applied @ 10 tons, 150 kg, 105 kg and 175 kg per hectare, respectively. the total quantity of cow dung was applied during land preparation. half of the recommended quantity of urea, total quantity of tsp and half of mop were applied as top dressing after 30 days and the remaining halves of urea and mop after 45 days of seed sowing seed of three carrot varieties were sown on 5, 15 and 25 november 2015, respectively. irrigation, weeding and other intercultural operation was done according to need for proper growth and development of carrot root. carefully uprooted plants were pruned as per required extent (1//2 root and 3/4 th shoot) of the treatment. prior to transplanting, the cut stecklings were kept in the solution of dithane m-45 @ 2 g per litter of water for 5 minutes to prevent fungal infestation at the cut surface. the prepared stecklings of carrot were transplanted on 5, 15 and 25 january 2016 maintaining a spacing of 30 and 25 cm between the rows and stecklings, respectively. a little portion of the root was kept above the ground level at the time of transplanting. the transplanting was done in the afternoon. irrigation was given just after transplanting so that the roots get established properly in the soil, and it was continued given at 7-10 days interval. flowering and fruit setting are critical period for irrigation. thereafter it has stopped to enhance umbel maturity. weeding and mulching were done for four times during the experimental period to keep the plots free from weeds for conservation of moisture and better soil aeration and to break the soil crust. roughing was done at the time of flowering to maintain varietal purity. ten plants were selected randomly from each plot and data on different seed yield parameters were collected on individual plant basis from the selected plants. the data collected from the experimental plots were statistically analyzed. the mean values of all treatments were calculated and the analysis of variance for most of the characters was accomplished by f variance test. the significance of difference among the treatment means was evaluated by least significant difference (lsd) test at 5% levels of probability (gomez and gomez, 1984). table 1. initial soil status of the experimental plot soil properties/constituents values critical level soil ph 6.7 organic carbon (%) 0.86 total nitrogen (%) 0.16 0.12 available phosphorus (ppm) 17.05 10.00 available potassium (me/100g soil) 0.10 0.15 zinc (ppm) 10.35 1.15 sulphur (ppm) 5.85 8.00 boron (ppm) 5.85 8.00 molybdenum (ppm) 0.063 0.10 source: agrivarsity humboldt soil testing laboratory, department of soil science, bangladesh agricultural university, mymensingh 26 lutfunnahar et al. results and discussion plant height the influence of three different planting dates was found to be significant in respect of plant height at root harvest. it was observed that plant height decreased gradually with the advancement of planting time. the tallest plant (84.56cm) was obtained from p1 and the shortest plant (76.34 cm) was recorded from p2 (table 2). gogoi et al. (2016) obtained the similar results in broccoli. but varietal effect had no significant effect on plant height. the interaction of planting time and variety on the plant height was found to be significant. however, the highest plant height (86.41 cm) was observed in p1v1 and the lowest plant height (74.13 cm) was found in p3v3. days to 50% flowering and 50% fruit set the effect of planting time, variety and their interaction on days required to 50% flowering and 50% fruit set was found to be significant (table 2). however, p3 required the longest period for flowering (143.92 days) and fruiting (159.83 days) while p1 required shortest period for flowering and fruiting. this finding agrees with the reports of roberts et al. (1997) who stated that if cold temperatures are experienced early in growth stages, flowering of most biennial vegetable species is increased. lengthening the exposure of carrot to low temperatures increases vernalization response (sakr and thompson, 1942; dickson and peterson, 1958; hiller and kelly, 1979). contrary, the longest time required to 50% flowering (144.84 days) and fruiting (163.38 days) was found in the variety v3 while the shortest time for flowering (138.36 days) and fruiting (151.37 days) was in v1 (table 2). rashid (1976) reported the similar results regarding this parameter. in case of interaction effect, p3v3 required the longest period for flowering (146.80 days) and fruiting (165.20 days) whereas, p1v1 required the shortest period for flowering (136.08 days) and fruiting (148.60 days). days required from flowering to fruit set planting time had no significant effect on days taken from flowering to fruit set but effect of variety was significant. the maximum days (18.54) was required for variety v3 and the minimum days (13.01 days) required in the varicty v1. on the contrary, interaction of planting time and variety on days planting time effect on quality seed production of three varieties 27 required from 50% flowering to 50% fruit set was significant. the longest period (18.88 days) was found in the treatment combination p2v3 and the shortest period (12.52 days) was in p1v1. number of primary and secondary umbels per plant the effect of planting time had significant effect on the number of primary and secondary umbels per plant but not significant for variety (table 2). nevertheless, the maximum number of primary umbels (9.25) was found in early planting (p1) while it was the minimum (7.18) in the late planting (p3). these results were agreed with elballa and cantliffe (1996) who reported that the number of primary umbels decreased with the increasing temperature in late planting. flowering characteristics expressed as umbel size and number of umbellets, were observed to decline progressively along with the respective planting dates. similar trend was found for secondary umbels per plant. interestingly, varietal effect was not significant. the interaction of planting time and variety was highly significant in respect of number of primary umbels and secondary umbers per plant. the maximum numbers of primary umbels (9.62) per plant was obtained from the treatment interaction p1v1 which was statically identical with the interaction of p1v2 while the minimum number of primary umbels (7.13) per plant was found in the combination of p3v3. similarly, the maximum number of secondary umbels (8.38) was found in the treatment combination of p1v1 and the minimum number of umbels (6.01) was found in combination p3v3. table 2. effect of planting time, variety and their interaction on plant height and floral characters of carrot for seed production treatments plant height at 90 days (cm) days to 50% flowering days to 50% fruit set days required from flowering to fruit set no. of primary umbels/ plant no. of secondary umbels/ plant p1 84.56 139.93 155.83 15.89 9.25 7.69 p2 81.35 142.01 158.25 16.23 8.26 6.91 p3 76.34 143.92 159.97 16.04 7.18 6.09 level of sig. ** ** ** ns ** ** lsd(0.05) 3.01 1.95 2.10 0.30 0.23 0.24 cv (%) 5.13 1.41 1.32 1.06 12.58 11.60 v1 83.07 138.36 151.37 13.01 8.47 7.26 v2 80.06 142.67 159.30 16.62 8.22 6.92 v3 79.11 144.84 163.38 18.54 8.03 6.51 level of sig. ns * ** ** ns ** lsd(0.05) 3.68 5.48 5.03 0.50 0.28 0.29 cv (%) 2.56 2.32 3.86 7.49 2.68 5.45 p1v1 86.41 136.08 148.60 12.52 9.62 8.38 p1v2 84.07 140.83 157.40 16.57 9.18 7.65 p1v3 83.20 142.90 161.50 18.60 8.96 7.04 p2v1 83.02 138.60 151.82 13.22 8.54 7.27 p2v2 81.04 142.70 159.30 16.60 8.33 6.96 p2v3 80.00 144.75 163.63 18.88 7.92 6.50 p3v1 79.80 140.40 153.70 13.30 7.25 6.13 p3v2 75.09 144.50 161.20 16.70 7.16 6.15 p3v3 74.13 146.80 165.20 18.14 7.13 6.01 level of sig. * * ** ** ** ** lsd(0.05) 5.20 3.33 5.62 2.45 0.93 0.79 cv (%) 5.02 2.35 3.56 15.24 11.27 11.48 p1 = 5 january 2016, p2 = 15 january 2016, p3 = 25 january 2016 v1= ba (brassilia agroflora), v2= pa (prima agroflora), v3= nk (new kuroda) and ns non-significant 28 lutfunnahar et al. number of single umbels per compound umbel number of single umbels per compound umbel was significantly influenced by the time of planting, variety and their interaction. the maximum number (86.88) of single umbels per compound umbel was observed in p1 planting while it was minimum (76.71) in p3 planting (table 3). on the other hand, the highest number of single umbels (85.44) per compound umbel was recorded from the variety v1 while the variety v3 produced the lowest number of single umbels (78.36) per compound umbel. it was possible due to the higher number of primary and secondary umbels produced in the plant grown from ba variety. conversely, the maximum number of single umbels (91.47) was found in p1v1 combination and the minimum number of umbels (73.78) was in p3v3. number of flowers per single umbel the variation caused by the effect of planting time on number of flowers per single umbel was statistically significant. the maximum number of (53.51) of flowers per single umbel was observed in p1 planting and the minimum (49.21) was in p3 (table 3). the maximum number of flowers per single umbel (53.46) was found in the variety v1 and the minimum number of flowers (49.37) was in the variety v2. the interaction effect on the number of flowers per single umbel was also significant for the same parameters. however, maximum number of flowers (55.20) per single umbel was found from the treatment combination of p1v1 whereas, the minimum number of flowers (48.62) was recorded from the combination of p3v3 (table 3). table 3. effect of planting time, variety and their interaction on umbel characteristics of carrot for seed production treatments no. of single umbels/compound umbel no of flowers/single umbel diameter of main umbel (cm) diameter of primary umbel (cm) diameter of secondary umbel (cm) p1 86.88 53.51 14.82 8.77 4.86 p2 80.96 51.17 14.01 8.54 4.49 p3 76.71 49.21 13.30 8.40 4.12 level of sig. ** ** ** * ** lsd(0.05) 3.52 2.49 0.58 0.26 0.16 cv (%) 6.27 4.20 1.94 2.18 8.24 v1 85.44 53.46 14.71 8.41 5.53 v2 80.75 49.37 13.99 9.07 4.45 v3 78.36 51.05 13.55 8.22 4.69 level of sig. ** ** * ** * lsd(0.05) 4.31 3.05 0.72 0.32 0.20 cv (%) 4.42 4.01 3.00 5.21 11.60 p1v1 91.47 55.20 15.43 8.64 4.85 p1v2 86.00 51.60 14.89 9.23 4.76 p1v3 83.19 53.73 14.13 8.45 4.98 p2v1 84.30 53.60 14.83 8.33 4.45 p2v2 80.46 49.12 13.70 9.08 4.40 p2v3 78.12 50.18 13.50 8.21 4.62 p3v1 80.56 51.60 13.79 8.28 4.30 p3v2 75.80 47.41 13.40 8.92 4.20 p3v3 73.78 48.62 13.01 8.02 4.47 level of sig. ** ** ** ** ** lsd(0.05) 5.43 2.62 0.43 0.42 0.26 cv (%) 6.66 5.11 3.13 4.90 5.74 p1 = 5 january 2016, p2 = 15 january 2016, p3 = 25 january 2016 v1= ba (brassilia agroflora), v2= pa (prima agroflora), v3= nk (new kuroda) planting time effect on quality seed production of three varieties 29 diameter of main umbel different planting time, variety and their interaction had significant effect on the diameter of main umbel (table 3). however, the longest diameter (14.82 cm) was found in p1 planting and the shortest diameter (13.30 cm) was found in p3 planting. these results are in agreement with the findings of ali et al. (2014). similarly, the highest diameter of main umbel (14.71 cm) was found in the variety v1 and the lowest diameter (13.55cm) was in the variety v3. the interaction of p1v1 produced the maximum diameter of main umbel (14.43 cm) while p3v3 combination produced the minimum diameter (13.01 cm). table 4. effect of planting time and variety and their interaction on seed yield of carrot treatments seed yield in main umbel (g) seed yield in primary umbel (g) seed yield in secondary umbel (g) seed yield plant -1 (g) p1 1.76 2.74 1.62 6.18 p2 1.47 2.13 1.05 4.68 p3 1.24 1.54 0.76 3.68 level of sig. *** ** *** *** lsd(0.05) 0.23 0.22 0.24 0.58 cv (%) 14.63 8.60 7.80 5.54 v1 1.58 2.35 1.27 5.24 v2 1.50 2.06 1.08 4.67 v3 1.39 2.00 1.07 4.62 level of sig. ns * ns * lsd(0.05) 0.25 0.22 0.25 0.48 cv (%) 15.63 10.68 8.80 5.90 p1v1 1.85 2.90 1.75 6.70 p1v2 1.80 2.72 1.62 6.17 p1v3 1.63 2.60 1.50 5.67 p2v1 1.70 2.30 1.25 5.38 p2v2 1.50 2.10 1.00 4.57 p2v3 1.20 2.00 0.89 4.10 p3v1 0.95 1.85 0.83 3.66 p3v2 1.45 1.20 0.62 2.37 p3v3 1.33 1.59 0.83 4.11 level of sig * ns ** ** lsd(0.05) 0.94 2.01 1.37 1.97 cv (%) 17.96 12.47 15.02 7.95 p1 = 5 january 2016, p2 = 15 january 2016, p3 = 25 january 2016 v1= ba (brassilia agroflora), v2= pa (prima agroflora), v3= nk (new kuroda) and ns non-significant diameter of primary and secondary umbel the effect of planting time on the diameter of primary and secondary umbel was found significant. the early planting (p1) gave the highest diameter (8.77 cm and 4.86 cm) of primary and secondary umbel and late planting (p3) gave the lowest diameter (8.40 cm and 4.12 cm) of primary and secondary umbel. the diameter of primary and secondary umbel was also statistically influenced by three varieties of carrot. however, the maximum diameter of primary umbel (9.07 cm) was found in v2 and the minimum diameter (8.22 cm) was in the variety v3. on the contrary, the maximum diameter of 30 lutfunnahar et al. secondary umbel (5.53 cm) was found in the variety v1 and minimum (4.45 cm) in variety v2. the interaction effect of planting time and variety exhibited significant effect on the diameter of primary and secondary umbel. the maximum diameter of primary umbel (9.23 cm) of was found in the treatment combination of p1v2 and the minimum diameter (8.02 cm) was obtained from the combination of p3v3 treatment. similarly, the maximum diameter (4.98 cm) of secondary umbel was found in the treatment combination of p1v3 and the minimum diameter (4.20 cm) was obtained from the combination of p3v2 treatment. seed yield per plant significant variation was found on seed yield in main umbel, primary umbel and secondary umbel per plant respectively due to the different planting time. the highest seed yield in main umbel (1.76 g), primary umbel (2.74 g) and secondary umbel (1.62 g) was recorded at early planting (p1). a similar report was revealed by cardoso (2000), who stated that seeds in the primary umbels were of better seed yield and quality than the seeds of secondary umbel. the seed yield per plant is the total seed yield in main, primary and secondary umbels. the results of the planting time on the seed yield per plant showed that there was great variation in seed yield among the plants raised from different planting dates. seed yield was gradually decreased with the mid and late planting. early planting (p1) produced the highest seed yield (6.18 g) per plant followed by mid and late planting. the reasons of higher yield may be attributed to favorable temperature that prevailed during early planting. this result is in agreement with the finding of baljit and malik (1986). similarly, there was a significant effect among the three varieties of carrot. the maximum seed yield per plant (5.24 g) was obtained from the variety v1 possibly, due to the presence of higher number of single umbels per compound umbel and maximum number of flowers in every single umbel and the minimum seed yield (4.62 g) was found from the variety v3 which was statistically similar to v2. in case of interaction effect, the highest seed yield per plant (6.70 g) was found in the treatment combination of p1v1 and the lowest (2.37 g) was in combination of p3v2 (table 4). seed yield per hectare planting time, variety and their interaction effect on seed yield per hectare was noticed significant. the highest seed yield (527.92 kg ha -1 ) was found in early planting (p1) and the trend was gradually decreased with the advancement of planting time (fig. 2), and the lowest seed yield (314.75 kg ha -1 ) was found in late planting (p1). mengistu and yamoah (2010) reported that low temperature in early planting enhanced maximum seed yield as earlier planting seemed to obtain favorable climate for maximizing seed yield. this result is also in agreement with the findings of hossain et al. (2015). similarly, the highest seed yield (448.43 kgha -1 ) was produced by the variety v1 and the lowest seed yield (395.35 kg ha -1 ) was produced by v3 (fig. 2). this might be due to the fact that the variety brasilia agroflora had a good genetic potential which enhanced more cell division and cell elongation resulting best performance. malek et al. (2013) stated that the highest seed yield was recorded from brasilia agroflora and the quality of seed was produced from the same variety. mohanty and prusti (2001) reported that seed yields vary with the cultivars. however, the treatment combination of p1v1 produced the highest seed yield (572.37 kgha -1 ) and p3v2 produced the lowest (279.77 kg ha -1 ) seed yield of carrot (fig. 3). planting time effect on quality seed production of three varieties 31 seed quality parameters the term seed quality incorporates several attributes of seeds among which thousand seed weight and germination percentage were used in this study. 1000-seed weight planting time showed significant effect on 1000-seed weight. the maximum 1000-seed weight (1.75 g) was found in p1 planting time and minimum (1.43 g) in p3 planting time. these results are agreed with the finding of gray (1984). weight of 1000 seeds also varied significantly among the varieties of carrot. the highest 1000-seed weight (1.81g) was found in the variety v1 followed by v2 (1.56g) and the lowest (1.39 g) was recorded in the variety v3 (table 5). malik et al. (1988) found 1000-seed weight of carrot 0.96g. this result is in agreement with this finding. the interaction effect of planting time and variety also showed significant effect on 1000-seed weight. nonetheless, the maximum 1000seed weight of (1.98 g) was found in the combination of p1v1 and the minimum weight (1.28g) was in p3v3 combination. 32 lutfunnahar et al. table 5. effect of planting time, variety and their interaction on seed quality of carrot treatments 1000-seed weight (g) seed germination (%) p1 1.75 87.32 p2 1.56 80.84 p3 1.44 75.77 level of sig. ** ** lsd(0.05) 0.05 3.32 cv (%) 2.30 14.07 v1 1.81 87.32 v2 1.56 80.84 v3 1.39 75.77 level of sig. ** ** lsd(0.05) 0.06 4.08 cv (%) 2.33 15.96 p1v1 1.98 91.54 p1v2 1.73 86.52 p1v3 1.53 83.92 p2v1 1.87 82.60 p2v2 1.54 81.20 p2v3 1.28 78.72 p3v1 1.60 78.45 p3v2 1.43 75.12 p3v3 1.28 73.76 level of sig ** ** lsd(0.05) 0.11 5.78 cv (%) 5.38 16.88 germination percentage the percentage of germination varied with different planting dates. the maximum germination (87.32%) was found in the seeds of p1 planting and the lowest (75.77%) was in p3 planting (table 5). verma et al. (1993) obtained maximum (90.12-92.93%) and minimum (60%) germination due to climatic variations. the variation among the varieties on seed germination percentage was also significant. the variety v1 gave the highest germination percentage (84.19) followed by v2 (80.94%) and the lowest (78.80%) was obtained from the variety v3. malek et al. (2012) reported that the highest quality of seed (germination and vigour) was exhibited in brasilia agroflora followed by prima agroflora and the lowest quality of seed was observed in new kuroda variety. this might be due to higher thousand seed weight which enhanced the speed of germination. in case of interaction, the highest germination (91.54%) was recorded in the seeds produced from the treatment combination of p1v1 whereas the lowest germination (73.76%) was found from p3v3 treatment combination. conclusion the findings of this experiment revealed that the seed yield of carrot was significantly affected by different dates of steckling planting and carrot variety. brassilia agroflora (ba) planted on 5 january was suitable combination for maximum seed yield of carrot in mymensingh region of bangladesh. references ali, m.a., a. khurshidul, n. rezowana, m. mosfeq-ul-hasan, and m.d.a. mollah. 2014. effect of different sources of organic manure and sowing time on the growth and yield of carrot. int. j. sust. agric. technol. 10(5): 12-19. planting time effect on quality seed production of three varieties 33 anonymous. 1999. records of climatologically observations (daily); may 1998 to april 1999. weather yard, department of irrigation and water management, bangladesh agricultural university, mymensingh. baljit, s. and y.s. malik. 1986. effect of steckling planting dates and spacing on quality of seed produced by different orders umbels in carrot. haryana j. hort. sci. 15(3-4): 272-277. bbs. 2020. bangladesh bureau of statistics. statistics division, ministry of planning. govt. of the people’s republic of bangladesh. dhaka. bose, t.k. and m.g. som. 1986.vegetable crops in india. naya prokash, calcatta, india, pp.567-569. cardoso, a.i. 2000. yield and quality of carrot seeds from cultivars brasilia and carandai. bragantia brazil. 59(1): 77-81. dickson, m.h. and c.e. peterson. 1958. hastening greenhouse seed production for carrot breeding. proceed. american soc. horti. sci. 71: 412-415. elballa, m.m.a. and d.j. cantliffe. 1996. altermation of seeds stalk development, seed yield and seed quality in carrot by varying temperature during seed growth and development. j. amer. soci. hort. sci. 121(6): 1076-1081. gogoi, s., r.d. milu, p. bora, n. mazumdar and b.k. das. 2016. effect of sowing dates and spacing on broccoli (brassica leracea var. italica) seed production. indian j. agril. res. 50(4): 350-353. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research (2 nd ed.). john wiley and sons. new york. p.680. gray, d. 1984. the performance of carrot seeds in relation to their viability. ann. appl. biol. 104: 559-565 hiller, l.k. and w.c. kelly. 1979. the effects of post-vernalization temperature on seeds talk elongation and flowering in carrots. j. am. soc. hort. sci. 104: 253-257. hossain, m.f., n. ara, m.r. uddin, m.r. islam and m.z. azam. 2015. effect of sowing date and plant spacing on seed production of cauliflower. bangladesh j. agril. res. 40(3): 494-500. malek, m., d. mohammed, m. sikdar and m. rahman. 2013. effects of variety and growing condition on yield and quality of carrot seed. j. environ. sci. nat. resour. 5(2): 301-306. malek, m.a., d. mohammed, m. sikdar and m.s. rahman. 2012. effects of variety and weight of stecklings on yield and quality of carrot seed. j. agrofor. environ. 6(1): 47-50. malik, y.s., k.p. singh and p.s. yadav. 1988. effect of spacing and number of umbels on yield and quality of seed in carrot (daucus carota). seed res. 11(1): 63-67. mengistu, t. and c. yamoah. 2010. effect of sowing date and planting density on seed production of carrot (daucus carota var. sativa) in ethiopia. african j. plant sci. 4(8): 270-279. mohanty, b.k. and a.m. prusti. 2001. studies on genetics for production of seed crops. res. crops. 2(3): 378-381. peirce, l.c. 1987. vegetable characteristics, production and marketing. john wiley and sons. inc. new york. pp.251-52. rashid, m.m. 1976. bangladesher shabjee’ bangla academy, dhaka, bangladesh. p.308. roberts, e.h., r.j. summerfield, r.h. ellis, p.q. craufurd and t.r. wheeler. 1997. the induction of flowering. in: wien, h.c. ed. the physiology of vegetable crops. cambridge university press, cambridge. p.672. rubatzky, v.e., c.f. quiros and p.w. simon. 1999. carrots and related vegetable umbelliferae. cabi publishing, uk. p.294. sakr, s. and h.c. thompson. 1942. effects of temperatures and photoperiod on seed stalk development in carrot. proceed. american soc. hort. sci. 41: 343-346. sharfuddin, a.f.m. and m.a. siddique. 1985. shabjee biggan (in bengali). first edn. mrs. hassina akhtar beauty, bau, mymensingh. p.11. shinohara, s. 1984. vegetable seed production technology of japan. vol. i. shinohara’s authorized agricultural consulting engineer office. tokyo. pp.123-142. 34 lutfunnahar et al. undp. 1988. land resource appraisal of bangladesh for agricultural development report 2: agroecological region of banlgladesh, fao, rome, italy. p.577. verna, t.s., c. ramesh, s.c. sharma, k.d. lakhanpal, s. jhoshi and r. chand. 1993. effect of root size and umbel order on yield and quality of carrot (daucus carota var. sativus) seeds. inian j. agril. sci. 63(9): 574-577. bangladesh agron. j. 2025, 28(2): 61-65 yield performance of bwmri released wheat varieties in the border regions of bangladesh m. m. hossain1*, t. islam1, m. a. a. mamun1, m. s. n. mandal2, a. hossain3, m. a. hakim4, and m. m. bazzaz5 1on-farm research division, bangladesh wheat and maize research institute, nashipur, dinajpur-5200 2genetic resource and seed division, bangladesh wheat and maize research institute, nashipur, dinajpur-5200 3soil science division, bangladesh wheat and maize research institute, nashipur, dinajpur-5200 4wheat breeding division, bangladesh wheat and maize research institute, nashipur, dinajpur-5200 5agronomy division, bangladesh wheat and maize research institute, nashipur, dinajpur-5200 *corresponding author, email: mobarak.hossain@bwmri.gov.bd (received: 20 october 2025, accepted: 23 november 2025) keywords: exotic variety, food security, replace, yield, yield contributing characters abstract a field experiment was conducted during the rabi season of 2023–24 in three upazilas, haripur, baliadangi, and ranishankoil, of thakurgaon district of northern bangladesh to assess the feasibility of bwmri released new varieties against an existing exotic one (indian origin. seven wheat varieties (bwmri gom 1, bwmri gom 2, bwmri gom 3, bwmri gom 4, bari gom 30, bari gom 32, bari gom 33) taking an indian variety, sorna/china 3 as control. the experiment was laid out in rcbd with three replications. the unit plot size was 4 m × 5 m. seeding was done on 21 november 2023 in a continuous pattern at 20 cm line apart. the highest yield was observed in bwmri gom 2 (5.30 t ha-1) and bwmri gom 4 (5.10 t ha-1) against the lowest yield (3.23 t ha-1) in sorna/china 3. the yields of bari gom30, bari gom 32, bari gom 33, and bwmri gom 1 were comparable, ranging from 4.33 to 4.57 t ha-1. it was concluded the yield performance of bwmri gom 2 and bwmri gom is superior to sorna/china 3 in these areas. introduction wheat is the second most significant cereal crop in bangladesh, playing a crucial role in ensuring food security and supporting rural livelihoods (fpmu, 2024). in recent years, wheat consumption in the country has seen a notable increase, primarily driven by the expansion of the processed food industry, changes in dietary preferences, and the growing demand for bakery products and snacks (the daily star, 2025). as more bakeries and snack producers emerge across the country, the demand for wheat flour has risen sharply. this growing consumption underscores the importance of wheat in the national food system and economy. however, despite the increasing demand for wheat, the area available for wheat cultivation remains limited, mainly due to competition from other crops such as maize, boro rice, and other rabi (winter) crops. this competition poses a challenge to the expansion of wheat production, making it essential to explore ways to improve wheat yield and productivity in the country (fao, 2025). thakurgaon, a district situated near the indian border, stands out as the most productive region for wheat cultivation in bangladesh. according to the department of agricultural extension (dae) in 2023-24 season over 0.031 million hectares of land were cultivated for wheat in thakurgaon with a total production of 0.12 million tons (dae, 2023). this makes thakurgaon a significant contributor to the country's wheat supply. despite this, most farmers in the region continue to rely on wheat varieties imported from india, which have been traditionally adapted to the region’s agro-climatic conditions. however, the reliance on foreign varieties raises questions yield performance of bwmri released wheat varieties in the border regions of bangladesh 62 about their long-term sustainability, particularly in the face of changing climate conditions and emerging pest and disease challenges (hossain and da silva, 2013). in response to these concerns, the bangladesh wheat and maize research institute (bwmri) has developed new wheat varieties specifically designed to address the unique challenges faced by bangladeshi farmers in that particular region. these new varieties exhibit enhanced tolerance to terminal heat, which is crucial in the context of climate change, as rising temperatures pose a significant threat to wheat yields. additionally, these varieties show improved resistance to diseases that often affect wheat crops in bangladesh, further increasing their potential for higher productivity (bwmri, 2020-21). the bwmri varieties also promise increased yield potential, making them an attractive alternative for farmers seeking to improve their crop output (bwmri, 2021). given the importance of wheat in bangladesh’s food security and economic structure, it is crucial to assess the performance of these newly developed wheat varieties against the indian varieties currently in use, especially in boarder area. (alam et al., 2021) the findings of this experiment are expected to offer critical information about the potential advantages of adopting bwmri wheat varieties over exotic one considering climate resilience, disease resistance, and overall productivity. materials and methods the on-farm trial was conducted in three upazilas: haripur, baliadangi, and ranishankoil of thakurgaon district located at the aez 1: old himalayan piedmont plain (fig. 1), during rabi 2023–24. the field was medium high land having the soil properties presented in the table 1. a total of seven wheat varieties were used in the experiment, including bwmri gom 1, bwmri gom 2, bwmri gom 3, bwmri gom 4, bari gom 30, bari gom 32, bari gom 33, against one check, the indian variety, china 3/sorna. the experiment was laid out in rcb design with three replications in each site. the unit plot size was 20 square meters (5m × 4m). seeds were sown on 21 november 2023 in a continuous pattern with line to line 20 cm distance. the bwmri recommended seed rate, fertilizer dosage, and crop management practices were performed. soil properties were analyzed at the soil science lab, bwmri, dinajpur and the recorded data were analyzed with r software. table 1. soil properties of the experimental field properties value implication soil ph 5.97 near neutral sand content 67.7% rapid drainage silt content 15.36% moderate retention clay content 16.97% some retention texture sandy loam dries quickly flood risk above flood level safe, drought-prone sand/silt ratio 4.4 dominant sand silt/clay ratio 0.91 slightly more silt 63 hossain et al. fig. 1. map showing the sites of on-farm trials results and discussion data presented in table 2 revealed that the height of the plant (cm), number of spikelets and grains per spike, and weight (g) of thousand grains (tgw), as well as the grain yield (t ha-1) (fig. 2) varied significantly among the varieties. bari gom 33 was the tallest plant (102.3 cm) among the eight varieties. bwmri gom 1, bwmri gom 2, bwmri gom 3, bwmri gom 4, and bari gom 30 had moderate heights, ranging from 93 to 97.5 cm. the indian variety, sorna/china 3, was the shortest (79.9 cm), followed by the bari gom 30 (86.3 cm). moreover, bwmri gom 2, bwmri gom 3, bwmri gom 4 and bari gom 33 had the statistically similar highest number of spikelets per spike of around 18. the lowest spikelets/spike (14) was recorded from the sorna/china 3 followed by the rest of the varieties. table 2. effect of varieties on the yield attributes and yield of wheat variety plant height (cm) grain per spike (no.) spikelets per spike (no.) tgw bwmri gom 1 94.0bc 47ab 15b 51b bwmri gom 2 97.5b 43bc 18a 58a bwmri gom 3 96.0bc 51a 17a 46d bwmri gom 4 95.5bc 42bc 17a 56a bari gom 30 93.0c 44b 16b 47cd bari gom 32 86.3d 43bc 16b 49bc bari gom 33 102.3a 49a 18a 48cd sorna/china 3 79.9e 40c 14c 44e lsd (0.05) 1.37 4.14 0.83 1.22 cv (%) 2.54 5.88 5.49 4.22 tgw: thousand grain weight; lsd: least significant difference; cv: co-efficient of variance. means with similar letters are significantly identical yield performance of bwmri released wheat varieties in the border regions of bangladesh 64 furthermore, bwmri gom 1, bwmri gom 3, and bari gom 33 had the statistically similar highest number of grains per spike (47–51). china 3 recorded the lowest grains (40). the rest of the varieties had a moderate number of grains per spike, ranging from 42 to 44. the heaviest grains (1000-grain weight) were recorded from bwmri gom 2 (58 g), which is statistically similar to bwmri gom 4 (56 g), followed by bwmri gom 1 (51 g). the lowest grain weight was recorded from sorna/china 3 (44 g). the weight of the rest of the varieties ranged from 46–49 g. the highest values of several yield-contributing characters might have been attributed to the highest grain yield in bwmri gom 2 (5.30 t ha-1) and bwmri gom 4 (5.10 t ha-1) (figure 1). the lowest yield (3.23 t ha-1) was observed in china 3. the yields of bwmri gom 1, bwmri gom 3, bari gom 30, bari gom 32, and bari gom 33, ranged from 4.26 to 4.57 t ha-1. differences in grain yields among the varieties might be due to the inherent genetic quality of varieties that might have been influenced by the different yield contributing characteristics viz., number of spikelets, grains per spike, and weight of 1000grains in this study. fig. 2. effect of varieties on the grain yield (t ha−1) of wheat the yield performance of wheat varieties is influenced by a complex interplay of genetic, environmental, and management factors. genetically, each variety has a distinct yield potential, which is determined by key traits such as tiller number, spike length, grains per spike, and seed weight (chairi et al., 2020). modern wheat breeding efforts aim to enhance both yield potential and stress resilience to adapt to changing environmental conditions (yaghoubi khanghahi et al., 2021). environmental factors such as temperature, rainfall, and soil fertility significantly impact yield, with varieties exhibiting varying levels of performance under different climatic stresses (guijarro-real et al., 2025). furthermore, management practices, including sowing date, nutrient management, plant density, and irrigation, play a critical role in unlocking the genetic potential of a variety, ensuring it can thrive under local conditions (kumar and kumar, 2025). yield performance is also closely tied to yield components such as the number of effective tillers, grains per spike, and seed weight, which collectively contribute to the overall productivity of the variety (b. alam et al., 2024). moreover, genotype-environment-management (g × e × m) interactions b a b a b b b c 0 1 2 3 4 5 6 b w m r i g o m 1 b w m r i g o m 2 b w m r i g o m 3 b w m r i g o m 4 b a r i g o m 3 0 b a r i g o m 3 2 b a r i g o m 3 3 s o rn a / c h in a 3 y ie ld ( t h a − 1 ) cv=6.56 lsd (5%)=0.48 65 hossain et al. underscore the importance of considering both genetic traits and environmental conditions when assessing yield, as varieties may perform optimally in some environments while underperforming in others (martínez-peña et al., 2023). therefore, wheat breeding should not only focus on selecting high-yielding varieties but also ensure that agronomic practices are optimized to allow these varieties to express their full potential in specific environmental and management contexts. understanding and addressing these factors is crucial for improving wheat production and ensuring food security in diverse agricultural conditions. conclusion the results of this on-farm trial demonstrated that all the tested bwmri developed wheat varieties outperformed the indian variety sorna/china 3 in the tested areas. these findings indicate that bwmri varieties are better suited to boost wheat production, achieving superior yields and enhanced agronomic characteristics that could effectively substitute the sorna/china 3 variety in indian border regions of thakurgaon district. references alam, b., i. ullah, f. ullah, i. ullah khan, m.a. aslam, g. zahid, s. begum, a. errum, f. amin, r. ikram, m. murtaza, f. jabeen, e. yaseen, g.m. ali and s.h. khattak. 2024. morphological and yield characterization of different wheat genotypes. j. agric. vet. sci. 4(2): 2025-2151. alam, m.a., m. skalicky, m.r. kabir, m.m. hossain, m.a. hakim, m.s.n. mandal, r. islam, m.b. anwar, a. hossain, f. hassan, a. mohammadein, m.a. iqbal, m. brestic, m.a. hossain, k.r. hakeem and a. el sabagh. 2021. phenotypic and molecular assessment of wheat genotypes tolerant to leaf blight, rust and blast diseases. phyton-int. j. exp. bot. 90(4): 1301-1320. bwmri. 2021. bwmri annual research report 2020-21. bangladesh wheat and maize research institute, dinajpur, bangladesh. chairi, f., r. sanchez-bragado, m.d. serret, n. aparicio, m.t. nieto-taladriz and j.l. araus. 2020. agronomic and physiological traits related to genetic advance of semi-dwarf durum wheat in spain. plant sci. 295: 110210. dae. 2023. field crops wing report. department of agricultural extension, ministry of agriculture, government of the people’s republic of bangladesh. fao. 2025. country brief: bangladesh. global information and early warning system (giews). https://www.fao.org/giews/countrybrief/ fpmu. 2024. bangladesh food situation report. food planning and monitoring unit, ministry of food, bangladesh. guijarro-real, c., d. martín-lammerding, p. giraldo, e. benavente and m. ruiz. 2025. environmental clues for yield performance and stability of spanish bread wheat landraces. field crops res. 322: 109729. hossain, a. and j.a.t. da silva. 2013. wheat production in bangladesh: its future in the light of global warming. aob plants. 5: pls042. kumar, a. and m. kumar. 2025. effects of integrated nutrient management on wheat growth and yield under late-sown conditions. int. j. res. agron. 8(5): 375–382. martínez-peña, r., f.z. rezzouk, m.c. díez-fraile, m.t. nieto-taladriz, j.l. araus, n. aparicio and r. vicente. 2023. genotype-by-environment interaction for grain yield and quality traits in durum wheat: identification of ideotypes for castile and león. eur. j. agron. 151: 126951. the daily star. 2025. how wheat fuels a tk 16,000cr industry. the daily star. 10 september 2025. yaghoubi khanghahi, m., b. leoni and c. crecchio. 2021. photosynthetic responses of durum wheat to chemical and microbiological fertilization under salt and drought stresses. acta physiol. plant. 43(8): article 13289. blank page bangladesh agron. j. 2022, 25(2): 51-56 comparative productivity and profitability of chilli-legume vegetable intercropping systems j.a. chowdhury, a.a. begum, s.s. kakon, m.z. ali, m.a.h. khan and m.r. karim agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh corresponding e-mail: jasminedaisy.bari@gmail.com (received: 03 october 2022, accepted: 13 april 2023) keywords: chilli, legume vegetable, intercropping, chilli equivalent yield, benefit cost ratio abstract the field experiment was carried out on chilli legume vegetables intercropping system using five treatments at the agronomy research field of bangladesh agricultural research institute, gazipur during rabi season, 2019-2020 and 20202021. the study was conducted to find out the suitable intercrop combination for higher productivity and economic return. the treatments were viz., t1= sole chilli (60 cm × 50 cm), t2 = chilli (100%) + one row bush bean (50%), t3= chilli (100%) + two row bush bean (100%), t4= chilli (100%) + one row pea (50%), t5= chilli (100%) + two row pea (100%). significantly the highest yield (8.67 t/ha) was obtained in sole chilli. but chilli + one inter row pea intercropping system gave the highest chilli equivalent yield (21.47 t/ha). the highest gross margin (tk. 151896/ha) and bcr (3.42) were obtained from the same treatment. the results revealed that one row pea (50%) intercropped with chilli (100%) might be suitable intercrop combination for higher productivity and economic return. introduction intercropping system is an important feature of tropical agriculture which could be a viable option to increase productivity of crops per unit area and per unit time. intercropping is a crop management system involving growing of two or more dissimilar crops simultaneously on the same land area. it involves crop intensification in respect to both time and space dimensions (ahlawat and sharma, 2002) and increases total productivity through efficient utilization of land, labour, growth resources such as solar radiation and different inputs including fertilizer and water. it is a cropping system which integrates crop production with soil conservation. intercropping is an excellent technique to increase total productivity (islam et al., 2010), monetary return (begum et al., 2010) and resource use efficiency (islam et al., 2006) as well as to fulfill the diversified need of farmers (akhteruzzaman et al., 2008). moreover, it provides several major advantages namely; diversification reduces risk associated with crop failure, offers greater yield stability and utilizes the available growth resources more efficiently and sustainably (islam et al., 2006). the use of early maturing crop varieties, row arrangement, spacing and plant population are some important methods that help increase the yield of intercrop (rahman et al., 2009). better intercrop production could be achieved with the choice of the appropriate crops (santalla et al., 2001), population density and planting geometry of component crops (myaka 1995). benefits of intercropping may be briefed as: better use of resources, improvement of soil fertility by legume components of the system, soil preservation through covering the bare land between the rows, reduction of biotic and abiotic risks by increasing diversity, suppression of weed infestation etc. (van wolfswinkel, 2012). another advantage of mixing crop is the yield and quality improvement compared with sole cropping. the most 52 chowdhury et al. common crop combination in tropical intercropping systems is mixture of legumes and nonlegumes (wood and mayers 1987; fujita et al., 1990). inclusion of legumes enhances crop and nitrogen yields of the non-legumes (baker and blamey, 1985; wood and mayers, 1987). chilli is one of the major spices crops in bangladesh cultivated in 2, 49,748 acres of land (both winter and summer) with a production of 492000 metric tons (bbs, 2021). it is usually grown as sole and in some cases as intercrop in various parts of bangladesh. chilli is generally grown with wide row spacing about 60 cm, which makes it suitable for intercropping. intercropping of chilli with different vegetables offer greater scope to utilize the land and other resources to the maximum extent. productivity of the system can be enhanced by judicious selection of vegetables differing in duration and growth rhythms, so as to adjust the demand for the above and underground resources (suresha et al., 2007). so, in the inter-row space of chilli, legume crop such as french bean or pea can be introduced as intercrop for higher economic return as well as incorporated plant biomass can be improved soil nutritious status. therefore, this experiment was conducted to find out suitable legume vegetable species to grow as an intercrop with chilli for higher productivity and economic return. materials and methods a field experiment was conducted under irrigated condition during rabi season, 2019-2020 and 2020-2021 at the agronomy research field of bari, gazipur (23°53'-24°21'n latitudes and 90°09'-92°39'e longitudes). gazipur located at an elevation of 14 meters (45.93 feet) above sea level, a tropical wet and dry or savanna climate (classification: aw). the district’s yearly temperature is 28.95ºc (84.11ºf) and it is 1.21% higher than bangladesh’s averages. gazipur typically receives about 71.24 millimeters (2.8 inches) of precipitation and has 115.47 rainy days (31.64% of the time) annually. the soil of research area belongs to the chhihata series under aez-28. the soil was silty clay loam with ph 6.23, om 1.29% (very low), total n 0.112% (very low), exchangeable k 0.098 meq/100g soil (very low), available p 15.23μg/ml (optimum), available s 24.94 µg/g (optimum), available zn 0.654 µg/g (low) and available b 0.168 µg/g (very low). organic matter, n, k and b were under critical level in the soil. the experiment consisted of five different treatments viz., t1= sole chilli (60 cm × 50 cm), t2= chilli (100%) + one row bush bean (50%), t3= chilli (100%) + two row bush bean (100%), t4= chilli (100%) + one row pea (50%), t5= chilli (100%) + two row pea (100%). experiment was laid out in a randomized complete block design (rcbd) with three replications and each gross plot was of size 3.6 × 3.0 m2. bushbean (var. bari jharsheem-2) and pea (var. bari motorsuti3) were used as intercrop. chilli cv. bari morich-3 was transplanted with 2 seedlings per hill and later maintained one seedling per hill. the inter row spacing was 60 cm and intra row spacing was 50 cm. intercrops were sown between the rows. five tons of cowdung per ha was applied to the crop before transplanting. basal dose of fertilizer was applied @ 96-45-75-151.5-1.4 kg/ha n p k s zn b (frg, 2018). half of n and all other fertilizers were applied as basal during final land preparation. remaining n was applied in three equal splits at 25, 50 and 70 dat in chilli as ring method. under intercropping situation no additional fertilizer was applied. chemical fertilizers were used in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid. thirty days old seedling of chilli was transplanted on 21 november 2019 and 18 november 2020, respectively and intercrops were sown 10 days after planting of chilli in line according to the treatment combinations. intercultural operations and plant protection measures were taken up as and when required. first harvesting of chilli was done at 120 dap (days after planting) in 2020.and 118 dap in 2021 and harvesting was continued up to 196 dap in 2020 and 200 dap in 2021. french bean was harvested three comparative productivity and profitability of chilli-legume vegetable intercropping systems 53 times at 73, 78 and 85 das in 2020 and 75, 80 and 86 das in 2021. pea was harvested on 10 january 2020 and 8 january 2021. observations were taken on five randomly selected plants in each plot in respect to plant height, number of chilli fruits/plant, weight of chilli fruit, number of pods, pod length, single plant pod weight and yield. for economic analysis, gross income, total operational cost, gross margins and bcr were calculated. data on yield and yield contributing characters were taken and statistically analyzed following mstat-c software package. means were adjudged by lsd test at 5% level of significance. chilli equivalent yields (cey) were computed by converting yield of intercrops on the basis of prevailing market price of the individuals by using the formula of bandyopadhayay (1984). chilli equivalent yield (cey) = yield of component crop + where, yi = yield of component crop (pea/bushbean) in intercropping pi = price of component crop (pea/bushbean) in intercropping results and discussion yield and yield contributing characters of chilli the growth of chilli was found to be affected by the intercrops. the two years pooled yield and yield attributes data of chilli have been presented in table 1. the plant height was significantly lower in all the treatments than the sole (table 1). the plant height was comparatively higher in sole chilli (90.40 cm) and the lowest (61.15 cm) was recorded when two row bushbean intercropped with chilli at harvest. this might be due to insufficient nutrient uptake through competition in this intercropping system. similar results were also obtained by ahmed et al. (2018). the number of fruit/plant and weight of fruit/plant differed significantly due to influence exerted by different treatments. the maximum number of fruits/plant (232) and highest weight of fruit/plant (320.46 g) were observed in sole chilli, while the lowest number of fruits/plant (168) and weight of fruit/plant (186.44 g) were observed in chilli + two inter row bushbean intercropping. in sole chilli, the values of these parameters were more might be due to the utilization of wider space and less compitition for natural resources. similar results were observed by begum et al. (2015). yield of chilli varied from 6.72 t/ha to 8.67 t/ha due to influence exerted by different treatments. among the treatment combinations sole chilli gave the highest yield of 8.67 t/ha. among the intercropping systems, the highest chilli yield was recorded in chilli + single row pea cropping (8.57 t/ha) might be due to less competition for different growth resources. chilli yield was the lowest (6.72 t/ha) in the chilli + two inter row bushbean treatment, might be due to the large canopy of french bean which hampered the growth and yield of chilli. similarly, varghese et al. (1979) reported the negative effects of intercropping on yield of cabbage. islam et al. (2006) and santalla et al. (2001) also reported that seed yield was higher in monoculture as compared to their corresponding intercropped yield. the yield loss due to intercropping also reported by ahmed et al. (2013), muoneke and ndukwe (2008) and manga et al. (2003). intercropping system also significantly reduced chilli yield by 1 to 23% over sole chilli (table 1) might be due to inter-specific competition for space, solar radiation, nutrients and water. chilli + two row bush bean intercropping system reduced 23% chilli yield followed by chilli + two row pea (19%) while the minimum yield loss of chilli was found in chilli + one row pea (1%) followed by chilli + one row bush bean (4%) combinations. the yield loss due to intercropping also reported by ahmed et al. (2013). 54 chowdhury et al. table 1. crop characters and yield of chilli as influenced by different intercropping (pooled of 2019-2020 and 2020-2021) treatments plant height (cm) fruits/plant (no.) fruit weight/ plant (g) chilli yield (t/ha) intercropped chilli yield decreases over sole chilli (%) sole chilli (60 cm × 50 cm) 90.40 232 320.46 8.67 chilli (100%)+one row bush bean (50%) 72.15 196 255.65 8.31 4 chilli (100%)+two row bush bean(100%) 61.15 168 186.44 6.72 23 chilli (100%) + one row pea (50%) 78.70 215 229.55 8.57 1 chilli (100%) + two row pea (100%) 65.85 186 212.93 7.06 19 lsd(0.05) 13.56 11.11 77.05 0.22 cv (%) 6.49 4.55 3.89 2.29 yield of legume vegetables the two years pooled yield of pea and bush bean have been presented in table 2. the yield of pea and bush bean was significantly influenced by intercropped with chilli. among the intercropping combinations the higher yield of bushbean (11.15 t/ha) was recorded in t3 treatment (chilli 100% + two row bush bean 100%) and the lowest bushbean yield (8.17 t/ha) from t2 treatment (chilli 100% + one row bush bean 50%). this might be due to higher plant population in t3 treatment. in case of pea the similar trend also observed due to similar cause. the higher pea yield (7.14 t/ha) was recorded in t5 treatment (chilli 100% + two row pea 100%) and the lowest pea yield (6.45 t/ha) was obtained from t4 treatment (chilli 100% + one row pea 50%). ahmed et al., (2006) also reported similar result. table 2. yield of legume vegetables as influenced by intercropping (pooled of 2019-2020 and 2020-2021) treatments yield (t/ha) chilli (100%) + one row bush bean (50%) 8.17 chilli (100%) + two row bush bean (100%) 11.15 chilli (100%) + one row pea (50%) 6.45 chilli (100%) + two row pea (100%) 7.14 lsd(0.05) 1.57 cv (%) 3.89 equivalent yield and cost and return analysis total productivity of system was expressed in chilli equivalent yield (cey). chilli equivalent yield (cey) and cost benefit analysis data are presented in table 3. the chilli equivalent yield was influenced in response to different intercropping systems (figure 2). all intercropping gave higher cey than sole chilli indicating higher productivity than sole cropping. among those, the highest cey (21.47 t/ha) was observed in chilli + one row intercrop pea combination followed by t5 combination (21.34 t/ha) and the lowest (8.67 t/ha) was observed in sole chilli. maximum cey in aforesaid combination was observed due to additional yield of component crop. further, economics of different chilli intercropping system was analyzed taking into account the prices prevailed at local market. though, the sole chilli gave significantly the highest yield per ha but gross return and gross margin/ha were highest in all intercropped treatments because of higher cye. considering the economics of intercropping in chilli, chilli + one interrow pea was found to be the best with highest gross return (tk. 214700/ha) and gross margin (tk. 151896/ha) comparative productivity and profitability of chilli-legume vegetable intercropping systems 55 where as next best treatment was chilli + two inter row pea (tk. 213400/ha and tk. 150449/ha respectively. the highest bcr (3.42) was observed in chilli + one row intercrop pea intercropping system followed by chilli + two rows inter crop pea (3.39). cost of production of all intercropping systems was more than sole chilli because of the involvement of higher seed cost as well as cost of more labours engaged in different operations. chilli + legume intercropping system increased total productivity by 90 -148% over sole chilli (table 3). among the treatments, cey in chilli + one row pea combination was 148% higher over the sole chill and lowest in chilli + one row bush bean. similar results were also reported by begum et al. (2015) in chilli + root crop intercropping systems. table 3. chilli equivalent yield and economics of different chilli intercropping (pooled of 20192020 and 2020-2021) treatments chilli equivalent yield (t/ha) % increase cey over sole chilli gross return (tk/ha) cost of cultivation (tk/ha) gross margin (tk/ha) bcr t1 8.67 86700 57000 29700 1.52 t2 16.48 90 164900 62280 102620 2.65 t3 17.87 106 178700 62876 115824 2.84 t4 21.47 148 214700 62804 151896 3.42 t5 21.34 146 213400 62951 150449 3.39 market price (tk./kg): chilli= 10, bushbean= 10, pea= 20 t1= sole chilli (60 cm × 50 cm), t2 = chilli (100%) + one row bush bean (50%), t3= chilli (100%) + two row bush bean (100%), t4= chilli (100%) + one row pea (50%), t5= chilli (100%) + two row pea (100%). conclusion it can be concluded that chilli intercropped with bushbean or pea produced higher yield than sole chilli. all studied combinations can be cultivated for higher productivity but chilli (100 %) + one row of pea (50%) in between chilli lines combination could be more suitable combination for higher productivity and profitability of intercrop, reference ahlawat, i.p.s. and r.p. sharma. 2002. agronomic terminology. indian society of agronomy, division of agronomy, indian agricultural research institute, new delhi, india. ahmed, f., m.n. islam, m.s. alom, m.a.i. sarkar and m.a. mannaf. 2013. study on intercropping leafy vegetables with okra (abelmoschus esculentus l.). bangladesh j. agril. res. 38(1): 137143. akhetruzzaman, m., m.n. islam, b.l. nag and m.t. rahman. 2008. productivity of potato-hybrid maize relay cropping under different fertilizer levels. eco-friendly agril. j. 1(5): 300-303. baker, c.m. and f.p.c. blamey. 1985. nitrogen fertilizer effects on yield and nitrogen uptake of sorghum and soybean grown in sole cropping and intercropping system. field crop res. 12: 233-240. begum, s.a., m.s. zaman and a.s.m.m. rahman khan. 2015. intercropping of root crops with chilli in charlands of mymensingh. progres. agric. 26: 109-114. begum, s., m.n. islam, m.t. rahaman, j.a. chowdhury and m.i. haque. 2010. suitability study of different chilli varieties for intercropping with sweet gourd. expt. biosci. 1(2): 1-4. 56 chowdhury et al. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council (barc), farm gate, dhaka 1215. 223p. fujita, k., s. ogata, k. matsumoto, t. masuda, g.k.o. budu and k. kuwata. 1990. nitrogen transfer and dry matter production in soybean and sorghum mixed cropping system at different population densities. soil sci. plant nutr. 36(2): 233-241. islam, m.n., m.a.i. sarker, m.k. islam, s. begum and m.a. mannaf. 2010. intercropping of brinjal with chilli under different planting geometry for higher productivity and return. j. expt. biosci. 1(2): 51-55. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effect on the physiological attributes and productivity of maize-bushbean intercropping system. bangladesh j. agril. res. 31(3): 353-364. muoneke, c.o. and o.o. ndukwe. 2008. effect of plant population and spatial arrangement onthe productivity of okra/ amaranthus intercropping system. j. trop. agric. food, environ extn. 7(1): 15-21. myaka, f.a. 1995. effect of time of planting and planting pattern of different cowpea cultivars on yield of intercropped cowpea and maize in tropical and subhumid environment. trop. sci. 35: 274-279. rahman, m.t., m.n. islam, m.i. ahmed, r.k. bhuiya and m.r. islam. 2009. intercropping mungbean with mukhikachu. annual research report (2009-2010). agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701. pp. 89-93. santalla m., a.p. rodino, p.a. casquero and a.m. de ron. 2001. interactions of bush bean intercropping systems in maize/ spinach-redamaranth intercropping. bangladesh j. agric. environ. 2(2): 69-76. suresha, b.a., t.b. allolli, m.g. patil, b.k. desai and s.a. hussain. 2007. yield and economics of chilli based intercropping system. karnataka j. agric. sci. 20(4): 807-809. van wolfswinkel, m. 2012. intercropping of annual foodcrops. from: www.allindiary.org. accessed: feb. 2nd. varghese, l., s.b. umale and m.p. kawthalkar. 1979. effect of intercrops on the growth and yield of cabbage. south indian hort. 38: 196-198. wood, i.m. and r.j.k. myers. 1987. food legumes in farming systems in the tropics and subtropics. in: wallis es, byth de (eds.) food legume improvement for asian farming systems. aciar, canberra, pp. 34–45. bangladesh agron. j. 2024, 27(2): 61-69 effects of nitrogen and different rates of pendimethalin with bispyribac-sodium on directseeded aus rice s. sultana1, a.k.m.r. amin 1, t.a. sourav 1, m.r.h. khan1, a.b.m.j. islam 2, s.m. masum1* 1department of agronomy, sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka-1207, bangladesh 2rice farming division, bangladesh rice research institute, gazipur, bangladesh *corresponding author, email: smmasum607@sau.edu.bd (received: 26 april 2025, accepted: 21 july 2025) keywords: dry direct-seeded rice (dsr), nitrogen rates, herbicide application, tiller number, dry weight, biological yield, harvest index abstract the study was conducted at sher-e-bangla agricultural university in bangladesh, aiming to investigate the effects of nitrogen rates and herbicides on the competitiveness and yield parameters of dry direct-seeded rice (dsr) from march to july 2022. there were two factors in the experiment: nitrogen rates of 60 kg ha−1 (n60) and 80 kg ha−1 (n80), and the application of pre-emergent herbicide pendimethalin followed by post-emergent herbicide bispyribac-sodium. the herbicide treatments included: no weeding (h0), pendimethalin at 1000 g a.i. ha−1 (h1), bispyribac-sodium at 25 g a.i ha⁻1 (h2), pendimethalin at 500 g a.i. ha−1 combined with bispyribac-sodium at 15 g a.i. ha⁻1 (h3), pendimethalin at 1000 g a.i. combined with bispyribac-sodium at 30 g a.i. ha−1 (h4), and pendimethalin at 1500 g a.i. ha−1 combined with bispyribac-sodium at 45 g a.i. ha−1 (h5). the split-plot design consisted of 12 treatment combinations and 3 replications, with main plots for nitrogen rates and subplots for herbicidal treatments using rice var. brri dhan98. the result showed that the highest tiller number hill−1 was recorded for 80 kg ha−1 combined with pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 at 30, 45, 60, and 75 das, respectively. the study also exhibits the impact of nitrogen rates and herbicides on the dry weight of plants in brri dhan98 under the dsr system. nitrogen rates did not significantly affect the dry weights of plants at 15, 30, and 45 days after sowing (das). however, the nitrogen rate of 80 kg n ha−1 resulted in the highest dry weight at 60 and 75 das. the study also found that the biological yield and harvest index of var. brri dhan98 were better (9.41 and 47.74, respectively) in 80 kg ha−1 combined with pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 30 g a.i. ha−1. introduction direct-seeded cultivation involves sowing the rice seeds directly in the field without the urgency of a nursery or transplanting operations (bista, 2018). though weed management remains a threat, direct-seeded rice (dsr) is achieving popularity in asia as it is a climate-smart and resource-efficient production method (ahmed et al., 2020). direct-seeded rice is a promising alternative to traditional transplanting systems. the usual method is water, labor, and energy intensive. on the contrary, dsr enhances planting efficiency and soil health, and reduces methane emissions along with retrenching the labor requirement by 11-66% compared to pre-germinated rice (rashid et al., 2009; kumar and ladha, 2011). in comparison with the puddled transplanted rice (ptr) system, weeds compete more intensively in the dsr system for resources with the crop seedlings starting from the germination stage (chauhan and johnson, 2011; chauhan and opeña, 2012). a 70-80% 62 sultana et al. grain yield of aus rice could be significantly hampered in the case of an improper weed management system (brri, 2008). among the weeding methods, manual weeding is widely used in bangladesh. again, the farmers mix either pre-emergence (pre) or post-emergence (post) herbicides with water for easy application. however, this method may not be enough to control the vast weed species in dsr fields (chauhan and opeña, 2012). seba (2022) also found that the application of the pre herbicide pendimethalin, succeeded by the post herbicide bispyribac-sodium, effectively mitigates weed proliferation and checks the emergence of resistant weed biotypes in the dsr system. the impacts of herbicides in dsr fields can fluctuate based on the n fertility levels present in the soil. elevated nitrogen applications can alter the biochemical properties of both the soil and the plants, potentially augmenting or diminishing the absorption and efficacy of specific herbicides (brochado et al., 2023). the study aims to compare n and herbicide requirements in dsr and evaluate the efficacy of preemergence pendimethalin followed by post-emergence bispyribac-sodium combinations. materials and methods the field experiment studied the combined effects of nitrogen and pendimethalin, along with varying rates of bispyribac-sodium, on the growth and yield of aus rice under dry directseeded conditions at sher-e-bangla agricultural university, dhaka-1207, bangladesh, from march to july 2022. the experimental field was located in aez-28 (the modhupur tract), with a ph range of 5.8 to 6.5. the soil was classified as silty clay, and rainfall during the growing period varied from 17 mm to 390.7 mm. aus rice var. brri dhan98 was used as the experimental crop. there were two factors in the experiment: nitrogen rates of 60 kg ha−1 (n60) and 80 kg ha−1 (n80), and the application of pre-emergent herbicide pendimethalin followed by post-emergent herbicide bispyribac-sodium. the herbicide treatments included: no weeding (h0), pendimethalin at 1000 g a.i. ha−1 (h1), bispyribac-sodium at 25 g a.i. ha−1 (h2), pendimethalin at 500 g a.i. ha−1 combined with bispyribac-sodium at 15 g a.i. ha−1 (h3), pendimethalin at 1000 g a.i. ha−1 combined with bispyribac-sodium at 30 g a.i. ha−1 (h4), and pendimethalin at 1500 g a.i. ha−1 combined with bispyribac-sodium at 45 g a.i. ha−1 (h5). the study employed a split-plot design with 12 treatment combinations, each replicated three times. the main plots varied in nitrogen levels, while the sub-plots incorporated different rates of pendimethalin and bispyribac-sodium. on march 21, 2022, the field was cultivated with a power tiller and irrigated after three ploughs and cross-ploughs. weeds and pests were cleared. by march 27, the final layout was completed; each plot was leveled with a wooden board. nutrients, including phosphorus (p), potassium (k), sulfur (s), and zinc (zn), were applied to rice per brri’s aus rice recommendations. fertilizer doses included: triple superphosphate (90 kg ha−1), muriate of potash (40 kg ha−1), gypsum (60 kg ha−1), and zinc sulfate (10 kg ha−1). all fertilizers, except urea, were applied during land preparation, with urea split into three applications: first at preparation, then at 25 days and 50 days after sowing, based on treatments. the field was irrigated only at the flowering stage of the tested crop. the data were analyzed and mean differences were assessed by using the least significant difference (lsd) test at a 5% significance level. results and discussion total number of tillers hill−1 the total number of tillers hill−1 did not significantly differ across different nitrogen rates except at 75 days after sowing (das) (table 1). the highest (9) number of total tillers hill−1 at 75 das was found with the n80 treatment, while the lowest (8) from the n60 treatment. the total number of tillers hill−1 of direct-seeded aus rice varied significantly as a result of the herbicides used (table 1). experimental results revealed that, at 15 das, the maximum tiller number hill−1 (5) was recorded from the combined pre-emergence herbicide pendimethalin 1000 g a.i. ha−1 + effects of nitrogen and pendimethalin with bispyribac-sodium on direct-seeded aus rice 63 post-emergence bispyribac-sodium 30 g a.i. ha−1. at 30 das, the maximum tiller number hill−1 (9) from mixed herbicide pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1. at 45 das, the highest tiller number hill−1 (13) was recorded from the pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4). at 60 das, the maximum tiller number in hill−1 (13) was recorded for pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4). the combined impact of pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) resulted in the highest tiller number hill−1 in both nitrogen doses (table 1). the tiller number hill−1 for n80 combined with h4 is 5, 9, 13, and 13 at 30, 45, 60, and 75 das, respectively. the combined effect of pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5) was also similar at 30, 45, 60, and 75 das, respectively, for n80h5. on the other hand, n60h0 resulted in the lowest tillers number hill−1. table 1. effect of nitrogen rates and pre and post-emergence herbicides rates on tiller number hill−1 of var. brri dhan98 under dsr system here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 treatments number of tillers 30 das 45 das 60 das 75 das nitrogen levels n60 3.83 6.38 8.89 8.00 b n80 3.61 6.61 9.22 9.22 a lsd (0.05) ns ns ns 0.48 cv (%) 8.96 15.60 3.19 3.87 pendimethalin fb. bispyribac-sodium rates h0 3.50 bc 4.67 d 6.83 d 4.17 e h1 3.67 b 6.17 c 8.83 c 8.83 c h2 3.00 c 4.67 d 6.17 d 6.17 d h3 3.83 b 7.83 b 9.83 b 9.83 b h4 4.67 a 9.00 a 12.83 a 12.83 a h5 3.67 b 6.67 c 9.83 b 9.83 b lsd (0.05) 0.55 0.77 0.68 0.67 cv (%) 12.34 9.80 6.27 6.48 nitrogen levels × pendimethalin fb. bispyribac-sodium rates n60h0 3.67 bc 4.33 f 5.33 g 0.00 h n60h1 4.00 ab 5.33 ef 9.00 de 9.00 de n60h2 3.00 c 5.00 ef 6.67 f 6.67 f n60h3 4.00 ab 7.67 bc 9.33 d 9.33 d n60h4 4.67 a 8.67 ab 12.33 b 12.33 b n60h5 3.67 bc 7.33 cd 10.67 c 10.67 c n80h0 3.33 bc 5.00 ef 8.33 e 8.33 e n80h1 3.33 bc 7.00 cd 8.67 de 8.67 de n80h2 3.00 c 4.33 f 5.67 g 5.67 g n80h3 3.67 bc 8.00 bc 10.33 c 10.33 c n80h4 4.67 a 9.33 a 13.33 a 13.33 a n80h5 3.67 bc 6.00 de 9.00 de 9.00 de lsd (0.05) 0.83 1.65 0.95 0.96 cv (%) 12.34 9.80 6.27 6.48 64 sultana et al. dry weight of plants though nitrogen rates didn’t play a role in causing significant differences in dry weights of plants at 15, 30, and 45 das but 80 kg n ha−1 resulted in the highest dry weight at 60 and 75 das (table 2). table 2. effect of nitrogen rates and pre and post-emergence herbicide rates on the dry weight of plants of var. brridhan98 under the dsr system treatments dry weight (g plant−1) 15 das 30 das 45 das 60 das 75 das nitrogen levels n60 2.42 5.58 12.95 29.21 b 31.21 b n80 2.53 5.00 14.08 35.19 a 37.03 a lsd (0.05) ns ns ns 1.12 0.97 cv (%) 11.17 15.85 6.09 2.43 1.99 pendimethalin fb. bispyribac-sodium rates h0 1.85 c 4.60 d 9.54 d 14.75 e 11.52 e h1 1.71 c 5.96 ab 13.95 b 29.97 c 36.04 c h2 2.84 b 5.42 bc 13.70 b 27.01 d 27.48 d h3 1.87 c 4.15 d 12.39 c 39.44 b 40.92 b h4 3.70 a 6.40 a 15.64 a 42.23 a 44.90 a h5 2.88 b 5.22 c 15.88 a 39.81 b 43.85 a lsd (0.05) 0.41 0.57 1.43 1.49 1.45 cv (%) 13.79 9.01 4.60 3.83 3.52 nitrogen levels × pendimethalin fb. bispyribac-sodium rates n60h0 1.19 fg 4.42 de 7.60 g 8.30 j 0.00 g n60h1 2.53 b-d 6.60 ab 13.32 cd 26.06 h 38.26 c n60h2 2.78 bc 6.27 ab 13.82 cd 25.72 h 26.54 e n60h3 1.71 ef 4.29 de 11.84 ef 38.32 de 40.97 b n60h4 3.69 a 6.80 a 15.13 ab 39.76 cd 41.24 b n60h5 2.61 b-d 5.09 c-e 16.01 ab 37.11 e 40.24 bc n80h0 2.51 cd 4.77 de 11.47 f 21.19 i 23.04 f n80h1 0.89 g 5.32 b-d 14.59 bc 33.88 f 33.83 d n80h2 2.91 bc 4.56 de 13.58 cd 28.31 g 28.42 e n80h3 2.02 de 4.02 e 12.93 de 40.56 bc 40.87 b n80h4 3.71 a 6.00 a-c 16.16 a 44.69 a 48.55 a n80h5 3.15 ab 5.36 b-d 15.75 ab 42.52 b 47.46 a lsd (0.05) 0.63 1.33 1.43 2.15 2.05 cv (%) 13.79 9.01 4.60 3.83 3.52 here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 dry weight of plants significantly differed due to the effect of herbicides (table 2). at 15 das, the maximum dry weight (g) (3.70) was recorded from the combined pre-emergence effects of nitrogen and pendimethalin with bispyribac-sodium on direct-seeded aus rice 65 herbicide pendimethalin 1000 g a.i. ha−1 + post-emergence bispyribac-sodium 30 g ai ha−1 (h4). at 30 das, a similar trend was followed. at 45 das, the highest dry weight (g) (15.88) was recorded from the pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5). at 60 das, the maximum dry weight (g) (39.81) was recorded from the pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4). lodhi (2016) also found that weed control treatments significantly impact dry matter accumulation after sowing. weedy check plots had the lowest dry matter production but increased significantly with weed control treatments at all growth intervals. pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) resulted in the dry weight (g) in both nitrogen doses (table 2). dry weight (g) for n80h4 was 3.71, 6.00, 16.16, 44.69, and 48.55 at 15, 30, 45, 60, and 75 das, respectively. the effect of 80 kg n ha−1 and pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5) was also satisfactory for n80h5. on the other hand, n60h0 resulted in the lowest dry weight (g). no. of panicles m−2 the number of panicles m−2 was significantly affected by nitrogen rates. the maximum number of panicles m−2 was recorded with 80 kg n ha−1, compared with 60 kg n ha−1 was 151 m−2 (table 3). panicle number (250 m−2) was higher in the herbicide-treated plots than in the weedy check plots and was the highest in the highest dose of pre-post emergence herbicide, i.e., pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5) (table 3). on the other hand, the lowest number of panicles was observed at the plots from the control (0 m−2). similar results were also noted by hossain (2015). the combined effect, pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5) resulted in the highest number of panicles m−2 (255 m−2) at the nitrogen dose of 60 kg n ha−1 (table 3). on the other hand, n60h0 resulted in the lowest no. of panicles m−2 (0 m−2). panicle length (cm) the panicle length (cm) was significantly affected by nitrogen rates. the highest panicle length (14.87 cm) was recorded for the plots treated with 80 kg n ha−1, (table 3). the panicle length (19.55 cm) was higher in the herbicide-treated plots than in the weedy check plots and gave the highest, followed by pre-post emergence herbicide, i.e., pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) (table 3). on the other hand, the lowest panicle length (cm) was observed at the control plot. according to research by jabran et al., (2012), using herbicides to suppress weeds produces longer panicles than the weedy check (control). pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) resulted in the maximum panicle length (20.56 cm) at 80 kg n ha−1 (table 3), followed by n80h5 with 80 kg n ha−1, and the herbicide dose was pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (19.59 cm). on the other hand, n60h0 resulted in the lowest no. of panicles m−2 (0 cm). number of filled grains panicle−1 the highest number of filled grain panicle−1 (37) was recorded for the plots treated with 80 kg n ha−1 (table 3). yesuf and balcha (2014), chamely et al., (2015), and zhang et al., (2020) have documented that the application of nitrogen fertilizer has a notable impact on rice grains, specifically length and width. pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 treated plots had more filled grain panicle−1 than the other combinations (table 3). on the other hand, the lowest number of filled grain panicle−1 was observed from the control plots (0). n80h5 resulted in the most filled grain panicle−1 (72), at the nitrogen dose of 80 kg n ha−1, while n60h0 resulted in the lowest number of filled grain panicle−1 (0). 1000-grain weight the 1000-grain weight (g) was significantly affected by nitrogen rates. the highest number of 1000-grain weight (17.89 g) was recorded from 80 kg n ha−1 pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 treated plots, which had more 1000-grain weight 66 sultana et al. than the other combinations (table 3). the 1000-grain weight (g) was higher in the herbicidetreated plots than in the weedy check plots and gave the highest (23.67 g) from treatment h5. the result of pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) was also similar to h5 (22.33 g). table 3. effect of nitrogen rates and pre and post-emergence herbicides rates on yield contributing parameters of var. brri dhan98 under dsr system treatments panicle m−2 (no.) panicle length (cm) filled grains panicle−1 (no.) 1000-grain weight (g) nitrogen levels n60 151 b 12.23 29.83 b 13.94 b n80 156 a 14.87 36.78 a 17.89 a lsd (0.05) 2.48 1.58 3.52 0.86 cv (%) 20.76 15.83 7.37 3.78 pendimethalin fb. bispyribac-sodium rates h0 0.00 d 0.00 d 0.00 e 0.00 d h1 210.00 b 16.29 b 29.33 c 19.50 b h2 42.00 c 7.00 c 9.50 d 9.17 c h3 206.40 b 19.11 a 26.33 c 20.83 b h4 212.40 ab 19.55 a 63.67 b 22.33 a h5 250.20 a 19.36 a 71.00 a 23.67 a lsd (0.05) 38.77 1.40 4.53 1.39 cv (%) 20.97 8.56 11.29 7.22 nitrogen levels × pendimethalin fb. bispyribac-sodium rates n60h0 0.00 e 0.00 e 0.00 g 0.00 g n60h1 200.40 bc 16.99 b-d 26.33 e 20.33 de n60h2 0.00 e 0.00 e 0.00 g 0.00 g n60h3 211.20 a-c 18.72 a-c 19.67 f 19.33 d-f n60h4 238.80 a-c 18.55 a-c 63.00 c 21.00 cd n60h5 255.60 a 19.13 ab 70.00 ab 23.00 ab n80h0 0.00 e 0.00 e 0.00 g 0.00 g n80h1 219.60 a-c 15.59 cd 32.33 de 18.67 ef n80h2 84.00 d 14.00 d 19.00 f 18.33 f n80h3 201.60 a-c 19.50 ab 33.00 d 22.33 bc n80h4 186.00 c 20.56 a 64.33 bc 23.67 ab n80h5 244.80 ab 19.59 ab 72.00 a 24.33 a lsd (0.05) 64.27 1.98 6.60 1.94 cv (%) 20.97 8.56 11.29 7.22 here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 effects of nitrogen and pendimethalin with bispyribac-sodium on direct-seeded aus rice 67 on the other hand, the lowest number of panicles was observed from the control plot (0 g). similar findings were reported by jabran et al., (2012). pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 (h5) resulted in the highest 1000-grain weight (g) at 80 kg n ha−1 (table 3). treatment n80h5 resulted in the highest 1000-grain weight (24.33 g), followed by n80h4 80 kg n ha−1, and the herbicide dose was pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 (23.67 g). on the contrary, n60h0 resulted in the lowest 1000grain weight (0 g). biological yield the biological yield was considerably different for nitrogen doses (fig. 1). the highest biological yield (4.60 t ha−1) was recorded with 80 kg n ha−1. fig. 1. effect of nitrogen rates and pre and post-emergence herbicide doses on biological yield. here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1. the biological yield significantly differed due to the herbicide application, where pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 treated plots had more biological yield (t ha−1) than the other combinations (fig. 2). fig. 2. effect of nitrogen rates and pre and post-emergence herbicide doses on harvest index (%). here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribacsodium 45 g a.i. ha−1 the biological yield (8.94 t ha−1) was higher in the herbicide-treated plots than in the weedy check plots. on the other hand, the lowest biological yield (t ha−1) was where weeding was not performed (0 t ha−1). hasanuzzaman et al., (2008) corroborate the findings that the 68 sultana et al. efficacy of the herbicidal interventions impacted the biological yield. pendimethalin 1000 g ai ha−1 + bispyribac-sodium 30 g a.i. ha−1 (h4) resulted in the highest biological yield of 80 kg n ha−1 (table 4). treatment n80h4 resulted in the highest biological yield (9.41 t ha−1) where n60h0 resulted in the lowest biological yield (0 t ha−1). harvest index the harvest index (%) was considerably different for nitrogen doses (fig. 2). the highest harvest index (31.06%) was recorded with 80 kg n ha−1. the harvest index (%) significantly differed due to the herbicide application. pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1 treated plots had more harvest index (%) than the other combinations (table 4 and fig. 3). the harvest index (45.76%) was higher in the herbicide-treated plots than in the weedy check plots, followed by (h4). on the other hand, the lowest harvest index (%) was observed where weeding was not performed (0%). pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 30 g a.i. ha−1 (h4) resulted in the highest harvest index (47.74%). at 80 kg n ha−1 (table 4). on the other hand, n60h0 resulted lowest harvest index (0%). table 4. effect of nitrogen rates and pre and post-emergence herbicide rates on the yield of var. brri dhan98 under the dsr system treatments biological yield (t ha−1) harvest index(%) n60h0 0.00 f 0.00 g n60h1 2.32 e 39.28 c n60h2 0.0 f 0.00 g n60h3 2.10 e 28.21 e n60h4 8.48 c 43.77 b n60h5 8.26 c 42.39 b n80h0 0.00 f 0.00 g n80h1 3.27 d 35.59 d n80h2 2.42 e 24.60 f n80h3 3.52 d 33.86 d n80h4 9.41 a 47.74 a n80h5 8.94 b 44.57 ab lsd (0.05) 0.43 3.43 cv (%) 6.02 6.30 here: n60=60 kg n ha−1 and n80=80 kg n ha−1; h0= no weeding, h1= pendimethalin 1000 g a.i. ha−1 + bispyribacsodium 0 g a.i. ha−1; h2= pendimethalin 0 g a.i. ha−1 + bispyribac-sodium 25 g a.i. ha−1; h3= pendimethalin 500 g a.i. ha−1 + bispyribac-sodium 15 g a.i. ha−1; h4= pendimethalin 1000 g a.i. ha−1 + bispyribac-sodium 30 g a.i. ha−1; h5= pendimethalin 1500 g a.i. ha−1 + bispyribac-sodium 45 g a.i. ha−1 conclusion the findings of this study showed that overall growth and crop production properties were significantly enhanced with fertilizer application of 80 kg n ha⁻1.moreover, weed control was found effective when pendimethalin @ 1500 g a.i. ha−1 in combination with bispyribacsodium @ 45 g a.i. ha⁻1 was applied. these findings have also resulted in an enhanced yield of dsr, as well as being effectively employed for weed management in direct-seeded aus rice of var. brri dhan98. effects of nitrogen and pendimethalin with bispyribac-sodium on direct-seeded aus rice 69 acknowledgment ` the authors gratefully acknowledge the financial support of the saures, sher-ebangla agricultural university, bangladesh, to conduct this research. references ahmed, s., m.j. alam, a. hossain, a.k.m.m. islam, t.h. awan, w. soufan, a.a. qahtan, m.k. okla and a.e. sabagh. 2020. interactive effect of weeding regimes, rice cultivars, and seeding rates influence the rice-weed competition under dry direct-seeded condition. sustainability. 13(1): 317. bista, b. 2018. direct seeded rice: a new technology for enhanced resource-use efficiency. int. j. appl. sci. biotechnol. 6(3): 181–198. brochado, m.g.d.s., l.b.x.d. silva, a.d.c. lima, y.m. guidi and k.f. mendes. 2023. herbicides versus nitrogen cycle: assessing the trade-offs for soil integrity and crop yield—an in-depth systematic review. nitrogen. 4(3): 296–310. brri (bangladesh rice research institute). 2008. brri annual internal review 2007–2008. soil science division, bangladesh rice research institute, gazipur, bangladesh. chamely, s., n. islam, s. hoshain, m. rabbani, m. kader and m. salam. 2015. effect of variety and nitrogen rate on the yield performance of boro rice. prog. agric. sci. 26(1): 6–14. chauhan, b.s. and d.e. johnson. 2011. row spacing and weed control timing affect yield of aerobic rice. field crops res. 121(2): 226–231. chauhan, b.s. and j. opeña. 2012. effect of tillage systems and herbicides on weed emergence, weed growth, and grain yield in dry-seeded rice systems. field crops res. 137: 56–69. hossain, m.h. 2015. efficacy and residual activity of herbicide on growth and yield of transplanted aus rice. m.sc. thesis, sher-e-bangla agricultural university, dhaka, bangladesh. jabran, k., ehsanullah, m. hussain, m. farooq, m. babar, m.n. doğan and d.j. lee. 2012. application of bispyribac-sodium provides effective weed control in direct-planted rice on a sandy loam soil. weed biol. manag. 12(3): 136–145. kumar, v. and j.k. ladha. 2011. direct seeding of rice: recent developments and future research needs. adv. agron. 111: 297–413. lodhi, r. 2016. efficacy of bensulfuron methyl + pretilachlor against weeds in transplanted rice. ms thesis, jawaharlal nehru krishi vishwa vidyalaya, jabalpur, india. rashid, m.h., m.m. alam, m.a.h. khan and j.k. ladha. 2009. productivity and resource use of direct(drum)-seeded and transplanted rice in puddled soils in rice–rice and rice-wheat ecosystems. field crops res. 113(3): 274–281. seba, m.s.z. 2022. influence of herbicides on growth, yield and controlling weeds in direct-seeded aus rice. ms thesis. sher-e-bangla agricultural university, dhaka, bangladesh. yesuf, e. and a. balcha. 2014. effect of nitrogen application on grain yield and nitrogen efficiency of rice (oryza sativa l.). asian j. crop sci. 6(3): 273–280. zhang, j., t. tong, p.m. potcho, s. huang, l. ma and x. tang. 2020. nitrogen effects on yield, quality and physiological characteristics of giant rice. agronomy. 10(11): 1816. bangladesh agron. j. 2021, 24(2): 13-20 arsenic stress tolerance in lentil varieties m. s. islam1 and m. h. sohag2 1professor, department of agronomy, sher-ebangla agricultural university, dhaka 2m.s. student, department of agronomy, sher-ebangla agricultural university, dhaka corresponding author: msislamsau@yahoo.com (received: 31 july 2021, accepted: 16 september 2021) keywords: soil arsenic, plant performance, seed arsenic, seed yield, lentil abstract a pot experiment was conducted inside a rainshelter in the department of agronomy, sher-e-bangla agricultural university, dhaka in 2016 to evaluate the arsenic (as) stress tolerance of seven lentil varieties, viz., barimasur-1, barimasur-2, barimasur-3, barimasur-4, barimasur-5, barimasur-6 and barimasur-7 against three levels of arsenic stress viz., no arsenic stress (control), 25 mg as / kg soil and 50 mg as / kg soil. arsenic treatment was imposed during pot filling with 10 kg airdried soil pot-1. the pots were fertilized with 0.225 g urea, 0.425 g tsp and 0.175 g mop pot-1 before seed sowing. six healthy seeds of seven lentil varieties were sown in each pot and the plants were thinned to four after three weeks later. it was observed that increasing levels of as significantly decreased pods plant-1, 1000 seeds weight, seed yield, stover yield, harvest index and relative values of these parameters, whereas increased seed arsenic content and relative seed arsenic content in all the lentil varieties studied. although barimasur-7, barimasur-6 and barimasur-5 gave the higher seed yield, their relative seed yield, relative values of yield components, relative stover yield and relative harvest index were lower, but seed arsenic content and relative seed arsenic content were higher compared to that of barimasur-1, barimasur-2, barimasur-3 and barimasur-4. therefore, barimasur-1, barimasur-2, barimasur-3 and barimasur-4 varieties were superior and safe for consumption considering seed arsenic content and suitable for breeding considering relative seed arsenic content under soil arsenic stress conditions. correlation studies indicated that as stress decreased relative seed yield by most negatively influencing the relative 1000 -seeds weight followed by relative pods plant-1, relative stover yield and relative seeds pod-1. introduction environmental pollution in bangladesh has been becoming worse day by day. the arsenic (as) contamination of groundwater has now become a serious threat to public health in bangladesh, as over 97% of its population is dependent upon groundwater for drinking purposes (ahmed, 2002, shankar and shanker, 2014). the most of districts in bangladesh is highly polluted with arsenic. the presence of high arsenic content in the soil has led to its accumulation in paddy, which has resulted in its collection at the concentration beyond the food safety threshold (zhu et al., 2008; zheng et al., 2011). lentil (lens culinaris l.) is one of the major pulse crops of the world. it is a principal source of protein in the human diet. in bangladesh, it ranks first among the pulse crops in terms of area and production (bbs, 2019). the national average yield and total production in bangladesh are 1230.92 kg/ha and 175384 tons, respectively. the total production is increasing day by day as such consumption also rapidly increasing in bangladesh (bbs, 2019). lentil is mainly cultivated in greater faridpur, jessore, kushtia, pabna, laksmipur, rajshahi where the soils and groundwater are contaminated with as (afzal et al., 1999; bamwsp, 2005; apsu, 2004). people of that as affected areas as well as of the whole country are at risk of consuming ascontaminated lentil and creating a serious problem for human mailto:msislamsau@yahoo.com 14 islam et al. health. several reviews have been examined the sources and behavior of as in different plants, but speciation and toxicity in lentil and its impact on sustainable agriculture are not established. under this circumstance, this experiment was initiated to examine the arsenic stress tolerance of seven lentil varieties. materials and methods a pot experiment was carried out at sher-e-bangla agricultural university in the rabi season of 2016 2017 to screen out seven lentil varieties against arsenic stress. the treatments consisted of the seven bari released lentil varieties (viz., bari masur 1, bari masur 2, bari masur 3, bari masur 4, bari masur 5, bari masur 6, and bari masur 7) and three arsenic treatments (control i.e., no arsenic, 25 mg as/kg soil, and 50 mg as/kg soil). the experiment was laid out in a randomized complete block design with 5 replications. fresh and healthy seeds of seven varieties of lentil were washed thrice in sterile distilled water and six seeds were sown in each earthen pot of equal sizes (30 cm in height and 40 cm in diameter). the soil was mixed, air-dried, and ground to a particle size of < 2 mm. ten kg of air-dried soil was put in each pot. seeds were sown in a clean soil (control) and a soil spiked with 25 and 50 mg as kg−1, added as sodium arsenate (as, mw 312.01 g/mol; technical grade, purity 98.5 %, sigma-aldrich, bangalore, india). before sowing seeds, the pots were fertilized with 0.225 g urea, 0.425 g tsp and 0.175 g mop pot-1, which resembled to 45, 85 and 35 kg ha-1 of urea, tsp and mop, respectively (ais, 2015). the pots were arranged in a completely randomized design, and the plants were grown in a net house covered with polythene sheets at the middle stage of vegetative growth. the plants were thinned to 4 per pot three weeks later. data were recorded on plant height, pods plant-1, seeds pod-1, 1000seed weight, stover yield plant-1, seed yield plant-1 and harvest index. relative values of all the plant characters studied and seed arsenic content was calculated as, relative value = value under as stress ÷ value under control condition. based on the relative values of all the plant characters studied and seed arsenic content, the lentil varieties tolerant and susceptible to as stress were selected. data were analysed and the means were compared by the least significance difference (lsd) test. results and discussion the effects of different levels of arsenic (as) on different yield attributes, yields and seed as content of seven lentil cultivars have been presented and discussed below: effects of arsenic on the production of pods and seeds of lentil arsenic (as) stress significantly reduced number of pods plant-1 in all the lentil varieties studied except brimasur-1 and barimasur-2 (table 1). the highest number of pods plant-1 was found in all the varieties with no as treatment and it was significantly decreased with the increasing level of as in all the varieties. the significantly lowest number of pods plant-1 was found in as50 (50 mg as kg-1 soil) in all the 5 varieties (brimasur-3, barimasur-4, barimasur-5, barimasur-6 and bariasur-7) which was statistically identical to that of all the varieties except barimasur-6. the reduction in number of pods plant-1 might be due to the reduction in translocation of photosynthates towards reproductive organs specially flower buds as a result of oxidative stress created by as stress. the negative effect on photosynthesis and also on increasing oxidative stress in rice due to arsenic stress was also reported by gautam et al. (2019) and gautam et al. (2020). the reduction in pods plant-1 was also reported by bustingorri and lavado (2014) in soybean. the number of seeds pod-1 was not significantly influenced by stress (table 1). the increasing level of as reduced number of seeds pod-1 in all the seven lentil varieties studied but reduction was statistically insignificant. the variable effect of as on number of seeds pod-1 or number of seeds per panicle were found by different researchers in different crops. arsenic stress tolerance in lentil varieties 15 table 1. pod and seed production of seven lentil varieties as influenced by arsenic level arsenic level pods plant-1 (no.) seeds pod-1 (no.) v1 v2 v3 v4 v5 v6 v7 v1 v2 v3 v4 v5 v6 v7 as0 25.9 21.5 37.1 37.7 38.1 45.3 56.9 1.18 1.21 1.27 1.33 1.42 1.57 1.64 as25 24.8 (0.956) 20.6 (0.958) 35.0 (0.943) 35.8 (0.950) 33.7 (0.885) 42.0 (0.927) 39.9 (0.701) 1.13 (0.958) 1.16 (0.959) 1.20 (0.945) 1.26 (0.947) 1.26 (0.947) 1.46 (0.930) 1.27 (0.774) as50 23.9 (0.923) 19.5 (0.907) 33.7 (0.908) 34.3 (0.910) 31.9 (0.837) 37.8 (0.834) 38.1 (0.670) 1.09 (0.924) 1.10 (0.909) 1.16 (0.913) 1.21 (0.910) 1.19 (0.838) 1.31 (0.834) 1.07 (0.652) lsd(0.05) 3.26 0.92 cv (%) 4.8 5.6 v1 = barimasur-1, v2 = barimasur-3, v3 = barimasur-3, v4 = barimasur-4, v5 = barimasur-5, v6 = barimasur-6, v7 = barimasur-7; as0 = no arsenic, as25 = 25 mg arsenic kg-1 soil, as50 = 50 mg arsenic kg-1 soil figures in the parentheses indicate relative values effects of arsenic on the seed size and stover yield of lentil different as levels had significant influence on 1000seeds weight of lentil varieties. in all the seven lentil varieties, as level decreased 1000seeds weight (table 2) with the increasing level of as. the decrease in 1000 -seeds weight in barimasur-1, barimasur-2, barimasur-3 and barimasur-4 due to as level was insignificant whereas, it was significantly increasd in barmasur5, barimasur-6 and barimasur-7. the highest 1000seeds weight in barimasur-5 (18.3 g), barimasur-6 (19.5 g) and barimasur-7 (20.6 g) were found in no arsenic (as0) treatment and the significantly lowest in as50 treatment. the lowest values for this parameter were 15.3 g for barimasur-5, 16.2 g for barimasur-6, and 13.5 g for barimasur-7. the treatment consisting 25 mg arsenic kg-1 soil (as25) produced lower 1000seeds weight and was statistically identical to that of both as0 and as50 in all the seven lentil varieties except barimasur-7. reduction in 1000 -seeds weight might be due to hamper lipid peroxidation, ion leakage, oxidative stress and photosynthesis. these results may also be supported by the findings of lersen et al. (1992) and ahmed (2002). stover yield stover yield of seven lentil varieties was significantly influenced by different levels of as (table 2). arsenic level decreased stover yield, seed yield, relative seed yield and harvest index of seven rice varieties with increasing level of as. the highest stover yield plant-1 and seed yield plant-1 in barimasur-1 (2.31 g), barimasur-2 (2.44 g), barimasur-3 (2.57 g), barimasur-4 (2.61 g), barimasur-5 (2.76 g), barimasur-6 (3.27 g) and barimasur-7 (4.05 g) were found in no arsenic (as0) treatment and the lowest in as50 treatment which were statistically identical to that of as25 treatment. the treatment consisting 25 mg arsenic kg-1 soil (as25) produced the intermediate but statistically identical values for stover yield to that of as0 (no arsenic) and as50 (50 mg as kg-1 soil) treatment. the decrease in stover yield might be due to the decrease in photosynthesis as well as dry matter production caused by arsenic stress as reported by srivastava and sharma (2013) in blackgram, hibo et al. (2013) in soybean. effects of arsenic on seed yield of lentil seed yield of seven lentil varieties was significantly influenced by different levels of as (table 3). arsenic level decreased seed yield of seven lentil varieties with increasing level of as. the highest seed yield plant-1 in barimasur-1 (2.11 g), barimasur-2 (2.22 g), barimasur-3 (2.34 g), barimasur-4 (2.37 g), barimasur-5 (2.43 g), barimasur-6 (2.89 g) and barimasur-7 (3.15 g) were found in no arsenic (as0) treatment and the lowest in as50 treatment and that were statistically identical to that of as25 treatment. the treatment consisting 25 mg arsenic kg-1 soil (as25) produced the 16 islam et al. intermediate but statistically identical values for seed yield plant-1 to that of as0 (no arsenic) and as50 (50 mg as kg-1 soil) treatment. table 2. weight of 1000seeds and stover yield of lentil varieties as influenced by arsenic levels arsenic level weight of 1000seeds (g) stover yield (g plant-1) v1 v2 v3 v4 v5 v6 v7 v1 v2 v3 v4 v5 v6 v7 as0 14.5 11.7 22.3 18.5 18.3 19.5 20.6 2.31 2.44 2.57 2.61 2.76 3.27 4.05 as25 13.8 (0.952) 11.2 (0.957) 21.1 (0.946) 17.5 (0.946) 16.2 (0.885) 17.4 (0.892) 16.4 (0.796) 2.20 (0.952) 2.32 (0.951) 2.42 (0.942) 2.48 (0.950) 2.44 (0.884) 3.02 (0.924) 2.84 (0.701) as50 13.4 (0.924) 10.6 (0.906) 20.3 (0.910) 16.9 (0.914) 15.3 (0.836) 16.2 (0.831) 13.5 (0.655) 2.12 (0.918) 2.21 (0.906) 2.33 (0.907) 2.38 (0.912) 2.31 (0.837) 2.73 (0.834) 2.72 (0.672) lsd(0.05) 2.56 0.16 cv (%) 4.8 5.4 v1 = barimasur-1, v2 = barimasur-3, v3 = barimasur-3, v4 = barimasur-4, v5 = barimasur-5, v6 = barimasur-6, v7 = barimasur-7; as0 = no arsenic, as25 = 25 mg arsenic kg-1 soil, as50 = 50 mg arsenic kg-1 soil figures in the parentheses indicate relative values effects of arsenic on the harvest index of lentil significant differences in harvest index due to arsenic level were found only in barimasur-6 and barimasur-7, whereas in all other lentil varieties differences were statistically similar (table 3). increasing arsenic level decreased harvest index in barimasur-6 at as25 and in barimasur-7 at as50, whereas increased in barimasur-7 at as25 (table 3). these findings are also inconformity with that of rahman et al. (2012) and smith et al. (2003). table 3. seed yield and harvest index of lentil varieties as influenced by arsenic level arsenic level seed yield (g plant-1) harvest index (%) v1 v2 v3 v4 v5 v6 v7 v1 v2 v3 v4 v5 v6 v7 as0 2.11 2.22 2.34 2.37 2.43 2.89 3.15 47.74 47.64 47.66 47.59 46.82 46.92 43.75 as25 2.02 (0.96) 2.12 (0.96) 2.21 (0.94) 2.25 (0.94) 2.15 (0.88) 2.58 (0.89) 2.51 (0.80) 47.87 (1.003) 47.75 (1.002) 47.73 (1.001) 47.57 (1.000) 46.84 (1.000) 46.07 (0.982) 46.92 (1.072) as50 1.95 (0.92) 2.01 (0.91) 2.13 (0.91) 2.16 (0.91) 2.03 (0.83) 2.41 (0.83) 2.06 (0.65) 47.91 (1.003) 47.63 (0.998) 47.76 (1.002) 47.58 (1.000) 46.77 (0.999) 46.89 (0.999) 43.1 (0.985) lsd(0.05) 0.13 3.06 cv (%) 6.1 5.8 v1 = bariomasur-1, v2 = barmasur-3, v3 = barimasur-3, v4 = barimasur-4, v5 = barimasur-5, v6 = barimasur-6, v7 = barimasur-7; as0 = no arsenic, as25 = 25 mg arsenic kg-1 soil, as50 = 50 mg arsenic kg-1 soil figures in the parentheses indicate relative values effects of arsenic on the seed arsenic content of lentil seed arsenic content was significantly influenced by as level. increase in arsenic level increased seed arsenic content (figure 1). seed arsenic content was significantly highest in barimasur-7, which was statistically identical to that of barimasur-6, whereas, it was significantly the lowest in barimasur3, which was statistically followed by that of barimasur-4, barimasur-1 and barasur-2 both under as25 and as50 arsenic level. this findings were informity with that of alam et al. (2019) in other three varieties of lentil. arsenic stress tolerance in lentil varieties 17 v1 = barimasur-1, v2 = barimasur-3, v3 = barimasur-3, v4 = barimasur-4, v5 = barimasur-5, v6 = barimasur-6, v7 = barimasur-7 fig. 1. effect of arsenic level on as content in seed of seven lentil varieties (lsd0.05 = 3.56). effects of arsenic on the relative performance of lentil varieties increase in as level decreased relative values of all the parameters studied including relative seed yield and relative seed arsenic content (table 1, 2 & 3 ; figure 2). all the as level treatment significantly decreased relative seed yield in all the lentil varieties studied except barimasur-1 at as level as25. relative seed yield was significantly lowest in barimasur7 which was statistically identical to that of barimasur-5 and barimasur6, whereas it was significantly the highest in barimasur-1, which was statistically identical to that of barmasur-2, barimasur-3 and barimasur4 both under as25 and as50 arsenic level. relative seed as content was significantly highest in barimasur7, which was statistically identical to that of barimasur6, whereas, it was significantly the lowest in barimasur 3, which was statistically followed by that of barimasur4, barimasur1 and barimasur2 both under as25 and as50 arsenic level. these findings are also inconformity with that of rahman et al. (2012), smith et al. (2003) and alam et al. (2019). arsenic level s ee d a s co n te n t (p p m ) arsenic level file:///c:/users/p/appdata/roaming/microsoft/word/saures%20technuical%20report 18 islam et al. v1 = barimasur-1, v2 = barimasur-3, v3 = barimasur-3, v4 = barimasur-4, v5 = barimasur-5, v6 = barimasur-6, v7 = barimasur-7 fig. 2. effect of arsenic level on relative as content in seed of seven lentil varieties (lsd0.05 = 0.67). table 4. functional relationship between relative seed yield and other relative plant characters as affected by arsenic plant characters regression equation and correlation coefficient (r) relative pods plant-1 y = 0.669x + 0.289 r= 0.94** relative seeds pod-1 y = 0.687x + 0.280 r= 0.93** relative 1000 seeds weight y = 0.667x + 0.297 r= 0.94** relative stover yield y = 0.560x + 0.306 r= 0.93** **. correlation is significant at the 0.01 level (2-tailed) functional relationship between relative seed yield and relative yield components the significant positive correlations were found i) between relative pods plant-1 and relative seed yield (r = 0.94**), ii) between relative seeds pod-1 and relative seed yield (r = 0.93**), iii) between relative 1000 seeds weight and relative seed yield (r = 0.94**) and iv) between relative stover yield and relative seed yield ( r = 0.93**) under as stress condition (table 4). the functional relationships of relative seed yield with relative values of various yield components and stover yield studied indicated that the relative seed yield was most post positively correlated with the relative 1000seeds weight followed by relative pods plant-1, relative stover yield and relative seeds pod-1. these results again indicated that as stress decreased relative seed yield by most negatively influencing the relative 1000seeds weight followed by relative pods plant-1, relative stover and yield relative seeds pod-1. conclusion barimasur-1, barimasur2, barimasur3 and barimasur4 varieties were superior and safe for consumption considering seed arsenic content and suitable for breeding considering relative seed arsenic content under soil arsenic stress conditions. references r el at iv e se ed a s co n te n t arsenic level file:///c:/users/p/appdata/roaming/microsoft/word/paper-%20arsenic%20stress%20tolerance%20in%20seven%20lentil%20varieties.doc arsenic stress tolerance in lentil varieties 19 afzal, m.a., m.a. bakar and l.r. rahman. 1999. lentil cultivation in bangladesh. lentil blackgram mungbean development pilot project. pub. no. 18. bangladesh agricultural research institute, gazipur, bangladesh. ahmed, m.f. 2002. alternative water supply option for arsenic affected area of bangladesh. international workshop on arsenic mitigation in bangladesh, dhaka. ais (agriculture information service). 2015. masur (in bengali). agriculture information service. ministry of agriculture, govt. of people’s republic of bangladesh. dhaka, bangladesh. http://www.ais.gov.bd/site/ekrishi/96a49836-0765-4319-9c41. alam, m.z., m.a. hoque, g.j. ahammed, r. mcgree and l.c. boggs. 2019. arsenic accumulation in lentil (lens culinaris) genotypes and risk associated with consumption of grains. scientific reports. 9: 94319439. https://doi.org/10.1038/s41598-019-45855-z apsu (arsenic policy support unit). 2004. risk assessment of arsenic mitigation options, phase-i (rammo-i). dhaka: arsenic mitigation policy support unit and itb-bangladesh centre for water supply and waste management. bamwsp (bangladesh arsenic mitigation water supply project). 2005. bangladesh arsenic water supply project web site: www.bamwsp.org. bbs (bangladesh bureau of statistics). 2019. year book of agricultural statistics. bangladesh bureau of statistics. statistics division, ministry of planning, govt. of people’s republic of bangladesh. dhaka, bangladesh. begum, m., j. akter, m. jahiruddin and m.r. islam. 2008. effect of arsenic and its interaction with phosphorus on yield and arsenic accumulation in rice. j. bangladesh agril. univ. 6(2): 277–284. bustingorri, c. and r. s. lavado. 2014. soybean as affected by high concentrations of arsenic and fluoride in irrigation water in controlled conditions. agril. water management, 144: 134139. doi.org/10.1016/j.agwat.2014.06.004. choudhury, b., s. chowdhury and a.k. biswas. 2011. regulation of growth and metabolism in rice (oryza sativa l.) by arsenic and its possible reversal by phosphate. j. plant interact. 6: 15–24. doi: 10.1080/17429140903487552 gautam, a., a.k. pandey and r. dubey. 2019. effect of arsenic toxicity on photosynthesis, oxidative stress and alleviation of toxicity with herbal extracts in growing rice seedlings. indian j. agric. biochem. 32: 143–148. gautam, a., a.k. pandey and r.s. dubey. 2020. azadirachta indica and ocimum sanctum leaf extracts alleviate arsenic toxicity by reducing arsenic uptake and improving antioxidant system in rice seedlings. physiol. mol. biol. plants. 26: 63–81. doi: 10.1007/s12298-019-00730-z. hibo, l., y. lanfang and l. yadong. 2013. effects of soil arsenic on soybean main traits and chlorophyll content at different growing stage. acta agron. sin. 39(7): 13031308. doi.org/10.3724/sp.j.1006.2013.01303. jha, a. and r. dubey. 2004. carbohydrate metabolism in growing rice seedlings under arsenic toxicity. j. plant physiol. 161: 867–872. doi: 10.1016/j.jplph.2004.01.004. jha, a. and r. dubey. 2005. effect of arsenic on behaviour of enzymes of sugar metabolism in germinating rice seeds. acta physiol. plant. 27: 341–347. doi: 10.1007/s11738-005-0010-x. larsen, e.h., l. moseholm and m.m. nielsen. 1992. atmospheric deposition of trace elements around point sources and human health risk assessment uptake of arsenic and chromium by vegetables grown near a wood preservation factory. sci. total environ. 126(3): 263-275. mishra, s., a. jha and r. dubey. 2011. arsenite treatment induces oxidative stress, upregulates antioxidant system, and causes phytochelatin synthesis in rice seedlings. protoplasma. 248: 565–577. doi: 10.1007/s00709-010-0210-0. rahman, m.s., m.a. hossain, m.j.u. sarker and m.a. bakr. 2012. adoption and profitability of bari lentil varieties in some selected areas of bangladesh. bangladesh j. agril. res. 37(4): 593-606. http://www.ais.gov.bd/site/ekrishi/96a49836-0765-4319-9c41. https://doi.org/10.1038/s41598-019-45855-z http://www.bamwsp.org/ https://doi.org/10.1016/j.agwat.2014.06.004 http://zwxb.chinacrops.org/ https://doi.org/10.3724/sp.j.1006.2013.01303 20 islam et al. shankar, s. and u. shanker. 2014. arsenic contamination of groundwater: a review of sources, prevalence, health risks, and strategies for mitigation. sci. world j. 2014: 304524. https://doi.org/10.1155/2014/304524. smith, e., j. smith, l. smith, t. biswas, r. correll and r. naidu. 2003. arsenic in australian environment: an overview. j. environ. sci. health part a toxic/hazard subst. environ. eng. 38: 223–239. smith, e., r. naidu and a.m. alston. 1998. arsenic in the soil environment: a review. adv. agron. 64: 149–195. stoeva, n., m. berova and z. zlatev. 2003. physiological response of maize to arsenic contamination. biol. plant. 47: 449–452. doi: 10.1023/b:biop.0000023893.12939.48. zheng, m.z., c. cai, y. hu, g.x. sun, p.n. williams and h.j. cui. 2011. spatial distribution of arsenic and temporal variation of its concentration in rice. new phytol. 189: 200–209. doi: 10.1111/j.14698137.2010.03456.x. zhu, y.g., p.n. williams and a.a. meharg. 2008. exposure to inorganic arsenic from rice: a global health issue? environ. pollut. 154: 169–171. doi: 10.1016/j.envpol.2008.03.015. https://doi.org/10.1155/2014/304524 hibo, l., y. lanfang and l. yadong. 2013. effects of soil arsenic on soybean main traits and chlorophyll content at different growing stage. acta agron. sin. 39(7): 13031308. doi.org/10.3724/sp.j.1006.2013.01303. jha, a. and r. dubey. 2004. carbohydrate metabolism in growing rice seedlings under arsenic toxicity. j. plant physiol. 161: 867–872. doi: 10.1016/j.jplph.2004.01.004. bangladesh agron. j. 2022, 25(2): 1-9 growth and yield response of selected aman varieties as influenced by leaf cutting m.j. hossain1§, a.a.c. masud2*§, m.s. islam2, s. akhter3 and m.m. haque1 1department of agricultural botany, sher-e-bangla agricultural university, dhaka-1207 2department of agronomy, sher-e-bangla agricultural university, dhaka-1207 3institute of seed technology, sher-e-bangla agricultural university, dhaka-1207 *corresponding e-mail: chy.masud3844@sau.edu.bd (received: 11 june 2022, accepted: 05 december 2022) keywords: leaf removal, photo assimilation, modern rice, harvest index, flag leaf, penultimate leaf abstract sustainable crop production in the era of increasing input price is adding extra burden while the cultivable land is reducing at an alarming pace. this research article aims to test the hypothesis that the leaf cutting as an agronomic practice could be a better prospective in increasing rice grain production. an experiment was carried out in the experimental field of sher-e-bangla agricultural university, to assess the effect of leaf cutting on plant growth and yield of selected brri released aman varieties. the experiment consisted of five rice varieties namely brri dhan32, brri dhan33, brri dhan39, brri dhan62, and brri dhan56 treated either as control or leaf cutting (except flag and penultimate leaf). the experiment was laid out in randomized complete block design (rcbd) with three replicates. leaf cutting was observed with detrimental effect on the usual plant growth and yield performances. irrespective of all studied varieties, the highest value was obtained while no leaf cutting was performed. brri dhan39 was found to be the highest yield producing variety in terms of greater flag leaf length, leaf breadth, flag leaf area, required less time to grain filling, filled grain panicle-1, filled grain%, 1000grain weight, grain yield and harvest index in leaf cutting condition followed by brri dhan32 in terms of plant height, chlorophyll content, tiller hill-1 and straw yield. no significant differences in yield contributing parameters except the panicle hill-1 were observed in leaf cutting condition compared to control. leaf cutting at heading (except flag leaf and penultimate leaves) reduced average 10-20% loss of grain yield. brri dhan62 shown highly affected by leaf cutting compared to the rest other varieties. therefore, it can be concluded by suggesting that leaf cutting reduces plant functional efficiency which can be improved by enhancing photosynthetic capacity through proper management of leaf architecture. introduction rice (oryza sativa l.) is the staple food for over half of the world population and is the second most common cereal crop in the world (shang et al., 2020). around 75% of agricultural land in bangladesh is occupied by rice cultivation that contributes nearly 28% of the gdp (mazumder et al., 2020). ever increasing population is putting an extra pressure on cultivable land and is reducing cultivable land at 0.4% rate due to urbanization and industrialization (karmakar and karmakar, 2019). thus, rice output must be increased urgently through yield maximization to ensure long-term food security. proper agronomic management is necessary to maximize rice crop growth and grain yield. in bangladesh rice cultivation varies due to seasonal change in water supply. during the growing season, the mean temperature, and the total temperature variation, range, distribution pattern, and diurnal changes, or a combination of these may be mailto:chy.masud3844@sau.edu.bd 2 hossain et al. highly correlated with the grain yields of rice (islam et al., 2019). potential for increased rice production strongly depends on the ability to integrate a better crop management for the different varieties into the existing cultivation. variety itself is a genetic factor which contributes a lot in producing yield and yield components of a particular crop (mahmud et al., 2013). to increase cropping intensity and production, there is no alternative for cultivation of short duration variety and adoption of modern agricultural practices. there are several important factors those have tremendous influence on the growth and development, tiller production, grain formation and other yield contributing characters. flag leaf is metabolically active and has proved that the flag leaf, stem and head are the closest source food to the grain (rahman et al., 2013). flag leaf contributed to 45% of grain yield and is the single most component for yield loss through synthesis and translocation of photo-assimilates to the rice grain (das et al., 2017; karmakar and karmakar, 2019). the contribution of leaf removal in different rice cultivar was the minimum, suggesting the probability of maximum translocation of photosynthesis from stem to the grain during grain feeling stage of rice after leaf removal (abou-khalifa et al., 2008). since the productivity of a plant depends on the efficiency of its photosynthetic processes and therefore on the extent of its photosynthetic surface, the growth and development of leaves have a profound impact on the yield of the plant (mazur et al., 2019). the top three leaves have the greatest impact on grain yield. as a result, a thorough investigation of rice yield after chopping flag leaf and surrounding leaves was conducted (abou-khalifa et al., 2008). in order to improve rice grain yield, it is necessary to examine the morphological and physiological properties of functional leaves. another significant chemical involved in photosynthesis in plant leaves is chlorophyll, which has a direct impact on crop biomass and production. photosynthetic rate and chlorophyll content are linked. (mahmud et al., 2013). if leaf removal has no influence on grain production, it might become one of the most cost-effective ways to boost yield, with the added benefit of providing green fodder for farm animals. rice cultivation's effectiveness as a dualpurpose crop is largely determined by improved agronomic techniques and cutting time. for collecting enough fodder without reducing grain productivity, the timing of cutting rice leaves and the selection of an appropriate variety appear to be crucial. considering the above facts, the present study was carried out to evaluate yield, yield related parameters and quality of selected rice cultivars as influenced by leaf cutting. materials and methods the experiment was conducted at the research field of sher-e-bangla agricultural university, dhaka from july to december, 2016. five rice varieties released from bangladesh rice research institute (brri) were used as plant materials. the rice varieties used in the experiments were v1=brri dhan32, v2=brri dhan33, v3=brri dhan39, v4=brri dhan62, v5=brri dhan56. the seeds were collected from the brri, joydebpur. the experiment consists of two factors, factor a: five varieties, and factor bcontrol (c), and leaf cutting (lc; except flag and penultimate leaves). the experiment was laid out in randomized complete block design with three replications. rice seedlings were sown in the seedbed under the supervision of farm management division of sher-e-bangla agricultural university, dhaka. as per brri recommendation seedbed was prepared with 1 m wide and added nutrients as per requirements of soil. seed were sown in the seedbed @ 70 gm-2. the plot selected for the experiment was exposed to the sun for a week after initial soil opening. later on, the land was harrowed, ploughed and cross-ploughed several times followed by laddering to obtain a good tilth condition. weeds and stubble were removed and 10 tha-1 amounts of cowdung, tsp, mp, gypsum and zinc and 1/3 of urea were applied at the time of final land preparation at broadcasting method. half of the rest 2/3 of urea was applied at 25 days after transplanting (dat) and the rest amount of urea was applied at 45 growth and yield of aman varieties as influenced by leaf cutting 3 dat. the nursery bed was made wet by application of water one day before uprooting the seedlings. at 23 days after sowing, seedlings were uprooted and transplanted to the previously prepared main field, maintaining a distance of 25 cm × 20 cm. two seedlings hill-1 were used during transplanting. gap filling was done for all of the missing hills at 10 dat by planting same aged seedlings. first weeding was done from each plot at 15 dat and second weeding was done from each plot at 40 dat. the rice plant was harvested depending upon the maturity of grains and harvesting was done manually from each plot. maturity of crop was determined when 80-90% of the grains become golden yellow in color. ten randomly selected hills per plot from which different data were collected and 3 m2 areas from middle portion of each plot was separately harvested and bundled, properly tagged and then brought to the threshing floor. harvesting, threshing and cleaning of rice seed were done carefully. fresh weight of grain and straw were recorded plot wise. finally, the weight was adjusted to a moisture content of 13%. the data on plant height, leaf parameters, tiller hill-1, chlorophyll (chl) of flag leaf, panicle hill-1, grain panicle-1, grain filling time, filled and unfilled grain panicle-1 were collected before harvesting. after harvesting, the straw was sun dried and the yield parameter viz., grain yield, filled grain%, 1000-grain weight, straw yield, biological yield and harvest index were recorded accordingly. chlorophyll content was measured on fresh weight basis extracting with 80% acetone and used doubled beam spectrophotometer (model: u-2001, hitachi, japan) according to witham et al. (1986). the total chlorophyll content was estimated by adding chl a and chl b. harvest index was calculated dividing the grain yield by the total biological yield (grain and straw) of the same area and multiplying by 100. harvest index (%) = × 100 the data obtained for different characters were statistically analyzed to observe the significant difference among the treatment (statistix 10). the significance of the difference among the treatment means were estimated by the least significant difference (lsd) test at 5% level of probability. results and discussion effect of leaf cutting on growth parameters of rice plant growth parameters were significantly influenced due to leaf cutting. leaf cutting negatively impacted on different plant parameters. however, in all the tested parameters, the controls resulted with the highest performances compared to the respective other treatment. therefore, here we will consider the highest and lowest values of the varieties while leaf cutting was performed. plant height, leaf no. at heading the plant height of different varieties exhibited wide variation in length due to leaf cutting. the plant height was maximum (127.61 cm) in brri dhan33. the shortest plant height (97.26 cm) was found from brri dhan56. the remaining varieties were intermediate in this regard (fig. 1a). the number of leaves produced at heading of different rice cultivars showed no significant variation due to leaf cutting. therefore, less detrimental effect of leaf cutting was observed in varieties due to leaf cutting. however, the maximum numbers of leaves at heading (64.67) were produced by brri dhan62 which were statistically superior to the rest of the varieties. brri dhan32 and brri dhan39 produced second highest number of leaves which was also statistically different from the rest of the lines. the least number of leaves (53.67) produced by brri dhan56 while the other varieties took intermediate positions and they were statistically different among themselves (fig. 1b). confalonieri et al. (2011) detected plant height as a key factor to predict rice yield potential and established a model to estimate the plant height increase. similarly, karmakar and karmakar (2019) reported that plant height was significantly affected by 4 hossain et al. nitrogen rates and different leaf clipping times in brri dhan41. suprio et al. (2010) also found effective grains per panicle revealed significant positive relationship with plant height. it indicated that increasing plant height increases effective panicles per plant. fig. 1. combined effect of varieties and leaf cutting on plant height (a) and leaf number at heading (b) of rice. means with different letters are significantly different at p≤0.05 by lsd test. here c, lc denotes control and leaf cutting, v1v5; brri dhan32, brri dhan33, brri dhan39, brri dhan62, brri dhan56, respectively. leaf parameters (leaf length, breadth and area) leaf cutting significantly reduced the leaf length, breadth and area of flag leaf, penultimate and 3rd leaf in all five tested varieties compared to the control (table 1). however, due to leaf cutting the highest reduction of leaf length in flag leaf, penultimate and 3rd leaf 22.24, 23.37 and 17.29% was observed in v5, v4 and v2 variety, respectively. on the contrary, the highest flag, penultimate and 3rd leaf length was observed in v3, v3 and v5 variety, respectively (table 1). leaf length is very important in rice because leaf length is positively correlated with panicle length thereby was correlated with the grain yield of rice. genetic analysis of the morphological and physiological characteristics of functional leaves, especially flag leaf is found important for rice improvement program. it is noticed that when leaf length is high the panicle length is also high. rahman et al. (2013) observed length of flag leaf and panicle of two rice cultivars, br11 and brri dhan28 where flag leaf length positively correlates with yield and was highly significant. plants with greater flag leaf length had elongated panicle length, thus producing increased number of primary and secondary rachis resulted in increased number of grains in the panicle that ultimately improved the yield of the variety. flag leaf contributed to 45% of grain yield and is the single most component for yield loss. these results are in agreement with earlier reports on the contribution of flag leaf and top three leaves to grain yield (misra and misra, 1991). table 1. combined effect of varieties and leaf cutting on leaf length, breadth and area of rice treatment leaf length (cm) leaf breadth (cm) leaf area (cm2) f p t f p t f p t v1 37.22de 49.26cd 20.52cd 1.65bcd 1.56d 1.31fg 59.33cd 63.33c 29.67bc v2 38.52de 51.19bcd 18.26de 1.74ab 1.68cd 1.24g 61.67bcd 71.00b 32.33b v3 60.89b 66.86a 14.49f 1.77ab 1.84abc 1.83a 62.00bcd 59.00cd 25.67de v4 34.23e 28.49f 22.04bc 1.42e 1.38ef 1.44cd 42.67f 53.00ef 19.00f v5 38.60de 46.18d 25.82a 1.52de 1.30f 1.31efg 58.33d 51.00f 23.00e lsd(0.05) 5.48 6.59 3.08 0.16 0.17 0.10 3.99 5.07 2.66 cv (%) 7.06 7.47 8.59 5.88 6.32 4.13 3.96 4.71 5.59 combined effect of varieties and leaf cutting on leaf length, breadth and area of rice. means with different letters are significantly different at p≤0.05 by lsd test. here, v1v5; brri dhan32, brri dhan33, brri dhan39, brri dhan62, brri dhan56, respectively and f, p, t denotes flag leaf, penultimate leaf and 3rd leaf, accordingly. bc b a cd cd de b de e cd 0 20 40 60 80 100 120 140 160 v1 v2 v3 v4 v5 pl an t h ei gh t (c m ) c lc a bc a a cdbcd d bcd ab e 0 10 20 30 40 50 60 70 80 v1 v2 v3 v4 v5 le af n u m b er a t h ea d in g c lca b growth and yield of aman varieties as influenced by leaf cutting 5 thereby indicating, it is possible to improve grain yield by genetic improvement of length of flag leaf. furthermore, the highest leaf breadth reduction in flag, penultimate and 3rd leaf were 8.33, 24.75 and 12.83% in v1, v5 and v5, respectively compared to control. interestingly, variety v3 was reported with highest leaf breadth in all three mentioned leaves. blake et al. (200) found that potential yield and grain number were positively correlated with length, breadth and area of flag leaf. in terms of leaf area, the variety with highest value under leaf cutting condition is v3, v2 and v2 (62, 71 and 32 cm2 in flag, penultimate and 3rd leaf) respectively. however, less leaf area reduction in flag, penultimate and 3rd leaf was observed in v2, v2 and v1 variety, respectively compared to control (table 1). the grains yield and yield related traits were positively related to flag leaf area (bassuony and zsembeli, 2021). prakash et al. (2011) found that the grains yield was positively related with flag leaf area in rice varieties. chlorophyll content in flag leaf chlorophyll content of flag leaf at 12 days and at maturity from the study of five brri released rice varieties showed significant differences due to leaf cutting. results indicated that flag leaf contained increased amount of total chlorophyll at 12 days than that of at maturity for all of the studied varieties. however, highest reduction of chl 27.56 and 35.30% in flag leaf at 12 days and maturity was resulted in v3 variety compared to control (fig. 2). this might have happened due to the increased demand of photo assimilates for the growing panicle. any damage done to that flag leaf will have a direct and dramatic impact on crops potential. chlorophyll is positively correlated with photosynthetic rate. in rice, the leaf is metabolically active and critically important in determining yield. it has been assigned an important role in terms of supply of photosynthates to the grains (suárez et al., 2021). increased grain yield was observed by rahman et al. (2013) in brri dhan34 when chlorophyll was higher. abou-khalifa et al. (2008) also found the similar yield enhancing role of chl content in flag leaf in two rice cultivars. fig. 2. combined effect of varieties and leaf cutting on chl of flag leaf at 12 days after heading (a) and chl of flag leaf at maturity (b) of rice. means with different letters are significantly different at p≤0.05 by lsd test. here c, lc denotes control and leaf cutting, v1v5; brri dhan32, brri dhan33, brri dhan39, brri dhan62, brri dhan56, respectively. effect of leaf cutting on yield contributing parameters of rice different yield contributing characters viz. tillers hill-1, panicle hill-1, duration of grain filling, grain panicle-1, effective grain panicle-1 and filled grain% were significantly affected due to leaf cutting (table 2). no significant variation of tillers hill-1 was observed due to leaf cutting whereas, the panicle number hill-1 were significantly reduced by leaf cutting. the highest reduction (31.26%) of panicle was observed in v5 variety and the lowest (10.16%) was in v3 variety, compared to cd a b a d e bc f bcd e 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 v1 v2 v3 v4 v5 c h l a t fl ag le af ( m g g-1 f w ) c lc a b b cd ef b c d e f 0.0 1.0 2.0 3.0 4.0 5.0 v1 v2 v3 v4 v5 c h l a t fl ag le af ( m g g-1 f w ) c lca b 12 days after heading at maturity 6 hossain et al. the control. however, significant variance in grain filling duration was not observed due to leaf cutting although except v3 in rest other varieties, leaf cutting delayed the grain filling duration. in terms of grains panicle-1, filled grains panicle-1 and filled grain% were not significantly reduced due to leaf cutting whereas 24.84, 29.72 and 49.43% highest reduction was resulted in v2, v2 and v5, respectively (table 2). due to reduced photo assimilation and reduced tiller number highly impacted on the panicle number of the rice that leads to reduced panicle size and resulted in reduction of other yield contributing characters. this finding corroborates with the earlier findings of won et al. (2022) who reported that the greater sink size the higher is the grains panicle-1. table 2. combined effect of varieties and leaf cutting on yield contributing characteristics of rice treatments no. of tiller hill-1 no. of panicle hill-1 duration of grain filling no. of grains panicle-1 filled grain panicle-1 filled grain% c lc c lc c lc c lc c lc c lc v1 15.67ab 15.00b 17.70a 15.18b 33.00cd 34.67a-c 107.20cd 105.60cd 93.37b 89.38b 87.10ab 84.75ab v2 17.00a 15.00b 19.10c 14.39d 30.33de 35.33a-c 150.64a 113.23b 131.44a 92.37b 87.23ab 81.69bc v3 13.00c 12.67c 13.81d 12.41de 35.00a-c 29.00e 102.76d 104.35d 93.19b 90.78b 90.64a 86.98ab v4 11.33c 9.33d 16.41de 14.35e 36.33ab 37.33a 76.49e 66.32f 60.82c 50.67d 79.64bc 76.37c v5 13.00c 12.00c 15.36f 10.56g 31.00de 34.33bc 110.57bc 106.45cd 93.33b 92.97b 84.58ab 87.44ab lsd (0.05) 1.70 1.02 2.83 5.69 8.83 7.97 cv (%) 7.43 3.99 4.91 3.18 5.60 5.49 combined effect of varieties and leaf cutting on yield contributing characteristics of rice. means with different letters are significantly different at p≤0.05 by lsd test. here, v1v5; brri dhan32, brri dhan33, brri dhan39, brri dhan62, brri dhan56, respectively and f, p, t denotes flag leaf, penultimate leaf and 3rd leaf, accordingly. effect of leaf cutting on yield parameters of rice grain parameters significantly varied due to leaf cutting (fig. 3). the 1000-grain yield reduced in all tested varieties excepted increased in v5. the highest reduction of 1000-grain yield (13.43%) was observed in v2 variety (fig. 3a). significant variation in grain yield was observed in all varieties except v3 was observed under leaf cutting condition. the highest reduction of grain yield was (30.72%) in v2 variety compared to respective control (fig, 3b). straw yield significantly reduced under leaf cutting condition. however highest straw yield under leaf cutting condition was observed in v2 variety whereas the lowest was in v5 variety. on the contrary, v3 and v3 showed statistically similar yield. the highest reduction compared to control (31.79%) was observed in v5 followed by 25.05% in v2 variety (fig. 3c). the harvest index showed no significant differences between the control and the variety treated with leaf cutting. except v1 and v2, in rest three varieties leaf cutting increased harvest index significantly. in leaf cutting condition, the highest harvest index 56.51% followed by 54.74% was observed in v5 and v3, respectively (fig. 3d). results indicating yield was always significantly reduced when leaf was removed from the plant at panicle initiation stage. this is might be due to the inappropriate food supply to sink that mostly leaf does and thus the effect was observed as various defects in the floral identity. therefore, it is worth mentioning that leaf has a great contribution on yield. tambussi et al. (2007) also found the similar result and stated that grains filling is sustained by current photosynthesis of the upper parts of the plant, i.e., the flag leaf and penultimate leaves and the ear. growth and yield of aman varieties as influenced by leaf cutting 7 fig. 3. combined effect of varieties and leaf cutting on yield parameters: 1000-grain weight (a), grain yield (b), straw yield (c), harvest index (d) of rice. means with different letters are significantly different at p≤0.05 by lsd test. here c, lc denotes control and leaf cutting, v1v5; brri dhan32, brri dhan33, brri dhan39, brri dhan62, brri dhan56, respectively. correlation with other parameters from correlation analysis, it has been resulted those different parameters showed strong relation between each other. plant height showed strong correlation with most of the crop parameters. third leaf length showed negative correlation with leaf breadth and leaf are. in addition, duration of grain filling notably impacted yield and yield contributing characters. furthermore, harvest index has negatively affected by most of the plant parameters (table 3). gholizadeh et al. (2017) observed similar positive correlation among different leaf chl and nitrogen dynamics and their relationship to lowland rice yield for site-specific paddy management. table 3. correlation matrix of different plant parameters of rice here, ph, ln, dgf, gp, fgp, tsw, gy, sy and hi denotes plant height, leaf number, duration of grain filling, grain panicle-1, filled grain panicle-1, 1000-seeds weight, grain yield, straw yield and harvest index cd bc a bcd dd d b cd cd 0 5 10 15 20 25 30 35 40 v1 v2 v3 v4 v5 10 00 -g ra in w ei gn t (g ) c lc b a b b b d c b c c 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 v1 v2 v3 v4 v5 g ra in y ie ld (t h a-1 ) c lc cd a c cd d e b e e f 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 v1 v2 v3 v4 v5 st ra w y ie ld (t h a-1 ) c lc bc d c c b c d a b a 0 10 20 30 40 50 60 70 v1 v2 v3 v4 v5 h ar ve st in de x (% ) c lc a b dc ph flag penul. 3rd flag penul. 3rd ln flag penul. 3rd 12-d-head maturity t. hill-1 p. hill-1 dgf gp fgp f. grain % tsw gy sy hi ph 1.00 flag 0.49 1.00 penul. 0.57 0.79 1.00 3rd -0.24 -0.55 -0.52 1.00 flag 0.54 0.55 0.77 -0.61 1.00 penul. 0.63 0.69 0.74 -0.53 0.65 1.00 3rd 0.15 0.83 0.49 -0.52 0.33 0.48 1.00 ln 0.17 0.21 0.09 -0.30 0.36 0.32 0.45 1.00 flag 0.65 0.56 0.86 -0.27 0.71 0.61 0.14 -0.09 1.00 penul. 0.60 0.17 0.51 -0.29 0.59 0.62 -0.07 0.33 0.61 1.00 3rd 0.66 0.17 0.58 -0.21 0.62 0.64 -0.19 0.13 0.71 0.90 1.00 12-d-head 0.40 -0.08 -0.19 0.14 0.00 0.21 -0.02 0.53 -0.15 0.41 0.27 1.00 maturity 0.45 0.15 0.44 -0.30 0.64 0.52 0.04 0.55 0.44 0.80 0.72 0.28 1.00 t. hill-1 0.52 0.07 0.49 -0.09 0.47 0.54 -0.28 -0.07 0.66 0.76 0.85 0.12 0.67 1.00 p. hill-1 0.19 -0.13 0.00 0.15 0.16 0.37 -0.11 0.46 0.10 0.64 0.53 0.69 0.58 0.50 1.00 dgf -0.13 -0.38 -0.44 0.06 -0.15 -0.45 -0.10 0.28 -0.50 -0.13 -0.23 0.26 -0.05 -0.38 -0.01 1.00 gp 0.55 0.23 0.57 -0.01 0.41 0.50 -0.21 -0.25 0.78 0.66 0.79 0.09 0.38 0.80 0.35 -0.49 1.00 fgp 0.58 0.32 0.64 -0.03 0.45 0.54 -0.13 -0.21 0.82 0.65 0.78 0.04 0.40 0.78 0.29 -0.52 0.97 1.00 f. grain % 0.44 0.47 0.63 -0.10 0.43 0.40 0.21 0.00 0.63 0.32 0.38 -0.20 0.29 0.39 -0.12 -0.38 0.42 0.63 1.00 tsw 0.45 0.73 0.56 -0.49 0.45 0.47 0.65 0.36 0.33 0.25 0.16 0.12 0.23 -0.06 -0.12 -0.20 0.08 0.22 0.52 1.00 gy 0.48 0.43 0.42 0.01 0.25 0.59 0.25 0.28 0.38 0.44 0.44 0.48 0.33 0.34 0.47 -0.52 0.49 0.51 0.27 0.43 1.00 sy 0.60 0.15 0.27 -0.06 0.34 0.58 -0.11 0.25 0.37 0.77 0.72 0.73 0.52 0.61 0.71 -0.22 0.63 0.58 0.07 0.20 0.71 1.00 hi -0.43 0.14 -0.03 0.15 -0.29 -0.33 0.30 -0.19 -0.18 -0.71 -0.63 -0.62 -0.50 -0.54 -0.63 -0.16 -0.39 -0.29 0.18 0.09 -0.11 -0.77 1.00 leaf breadth leaf area chlorophyll (flag leaf) leaf length leaf breadth leaf area chlorophyll (flag leaf) leaf length 8 hossain et al. conclusion leaf cutting has a detrimental effect on the normal growth and physiology of the rice crops. in all tested varieties in the present study, control treatments were reported with highest plant growth, leaf, yield contributing and grain yield parameters compared to the varieties treated with leaf cutting. based on the comparison of five rice varieties, brri dhan39 (v3) was found to be the highest yield producing variety in terms of greater flag leaf length, leaf breadth, flag leaf area, required less time to grain filling, filled grain panicle-1, filled grain%, 1000-grain weight, grain yield and harvest index in leaf cutting condition. brri dhan32 (v2) is the second highest performing variety considering plant height, chlorophyll content, tiller hill-1 and straw yield. leaf cutting at heading (except flag leaf and penultimate leaves) reduced avarage10-20% loss of grain yield. it has been seen from this experiment that brri dhan39 show less effected by leaf cutting on the other hand brri dhan62 shown highly affected by leaf cutting. hence it can be concluded that leaf cutting at heading stage is not a better practice and by developing the photosynthetic capacity of leaf is the key to overcome the photosynthate-source restriction on grain yield and to make a new breakthrough of yield potential in future development of rice. acknowledgement the authors acknowledged the farm division of sher-e-bangla agricultural university to provide the input materials and bangladesh rice research institute (brri) to supply the quality seeds that supported us a lot to conduct the study. references abou-khalifa, a.a.b., a.n. misra and a.e.a.k.m. salem. 2008. effect of leaf cutting on physiological traits and yield of two rice cultivars. afr. j. plant sci. 2(12): 147-150. bassuony, n.n. and j. zsembeli. 2021. inheritance of some flag leaf and yield characteristics by halfdiallel analysis in rice crops (oryza sativa l.). cereal res. commun. 49(3): 503-510. blake, n.k., s.p. lanning, j.m. martin, j.d. sherman and l.e. talbert. 2007. relationship of flag leaf characteristics to economically important traits in two spring wheat crosses. crop sci. 47(2): 491-494. confalonieri, r., s. bregaglio, a.s. rosenmund, m. acutis and i. savin. 2011. a model for simulating the height of rice plants. eur. j. agron. 34(1): 20-25. das, s.r., m.y. ali and m.m. islam. 2017. effect of leaf clipping on yield attributes of modern and local rice varieties. bangladesh rice j. 21(1): 101-104. gholizadeh, a., m. saberioon, l. borůvka, a. wayayok and m.a.m. soom. 2017. leaf chlorophyll and nitrogen dynamics and their relationship to lowland rice yield for site-specific paddy management. inf. process. agric. 4(4): 259-268. islam, a.r.m., s. shen, s. yang, z. hu and r. chu. 2019. assessing recent impacts of climate change on design water requirement of boro rice season in bangladesh. theor. appl. climatol. 138(1): 97-113. karmakar, b. and b. karmakar. 2019. effect of nitrogen rates and leaf clipping on forage and grain yield, and seed quality of transplant aman rice. bangladesh rice j. 23(2): 49-57. mahamud, j.a., m.m. haque and m. hasanuzzaman. 2013. growth, dry matter production and yield performance of transplanted aman rice varieties influenced by seedling densities per hill. int. j. sustain. agric. 5(1): 16-24. growth and yield of aman varieties as influenced by leaf cutting 9 mazumder, s.r., h. hoque, b. sinha, w.r. chowdhury, m.n. hasan and s.h. prodhan. 2020. genetic variability analysis of partially salt tolerant local and inbred rice (oryza sativa l.) through molecular markers. heliyon. 6(8): e04333. doi:10.1016/j.heliyon.2020.e04333. mazur, v.a., h.v. pantsyreva, k.v. mazur and i.m. didur. 2019. influence of the assimilation apparatus and productivity of white lupine plants. agron. res. 17(1): 206–219. misra, a.n. and m. misra. 1991. physiolgocal responses of pearl millet to agroclimatic conditions. in: r. prakash and a. ali (eds.) environmental contamination and hygien. jagmandir books, new delhi, india. pp. 165-175. prakash, m., a. anandan and b.s. kumar. 2011. varietal variations in flag leaf area and yield in mutant lines of py 5 rice. karnataka j. agric. sci. 24(4): 525-526. rahman, m.a., m.e. haque, b. sikdar, m.a. islam and m.n. matin. 2013. correlation analysis of flag leaf with yield in several rice cultivars. j. life earth sci. 8: 49-54. shang, f., x. chao, k. meng, x. meng, q. li, l. chen and j. wang. 2020. fine mapping of a grain shape gene from a rice landrace longliheinuo-dwarf (oryza sativa l. ssp. japonica). agron. 10(3): 380. doi:10.3390/agronomy10030380. suárez, j.c., j.a. polanía, j.a. anzola, a.t. contreras, d.l. méndez, j.i. vanegas, j.e. noriega, l. rodríguez, m.o. urban, s. beebe and i.m. rao. 2021. influence of nitrogen supply on gas exchange, chlorophyll fluorescence and grain yield of breeding lines of common bean evaluated in the amazon region of colombia. acta physiol. plant. 43(4): 1-15. suprio, c., k.d. pradip, g. biswajit, k.s. kalyan and b. bhubaneswar. 2010. quantitative genetic analysis for yield and yield component in rice. sci. biol. 2(1): 117-120. tambussi, e.a., j. bort, j.j. guiamet, s. nogués and j.l. araus. 2007. the photosynthetic role of ears in c3 cereals: metabolism, water use efficiency and contribution to grain yield. crit. rev. plant sci. 26(1): 1-16. won, p.l.p., n. kanno, n.p. banayo, c.s. bueno, p.s. cruz and y. kato. 2022. source–sink relationships in short-duration and hybrid rice cultivars in tropical asia. field crops res. 282: 108485. doi:10.1016/j.fcr.2022.108485. bangladesh agron. j. 2022, 25(2): 11-17 intercropping of dwarf yard long bean with maize under different planting system a.a. begum, j.a. chowdhury, m.z. ali, m.r. karim and d.a. choudhury agronomy division, bari, gazipur 1701 corresponding email: luckyshamol6869@gmail.com (received: 16 may 2022, accepted: 06 december 2022) keywords: planting system, par interception, ler, yield, bcr, maize, yard long bean abstract the field experiment was conducted at agronomy research field, bari, gazipur during kharif-1 season of 2020 and 2021 to find out suitable combination of maize and dwarf yard long bean intercropping for higher productivity and monetary advantage. treatments included in the experiment were: t1= maize normal row (mnr) +1 row dwarf yard long bean (dylb), t2= maize paired row (mpr) + 2 rows dylb, t3= mpr +3 rows dylb, t4= mpr + 4 rows dylb, t5= sole maize (60 cm x 20 cm) and t6= sole dylb (40 cm x 25 cm). light availability on dylb decreased with the increase of shade produced by maize canopy over the time up to 105 das. the lowest light availability on dylb was observed in t1 treatment and the highest light availability in sole dylb (t6). the maximum grain yield of maize was observed in sole maize decreased by 1-4 % among the intercrop treatments. the highest maize equivalent yield (13.75 t ha-1), gross return (tk. 247500 ha-1), gross margin (tk. 139000 ha-1) and benefit cost ratio (2.28) were observed int3 followed by t1. the highest land equivalent ratio (1.56) was also found in the same treatment. the results revealed that maize paired row + 3 rows dwarf yard long bean and hybrid maize normal row (60cm x 20cm) + 1 row dwarf yard long bean might be agronomically feasible and economically profitable for maize and dwarf yard long bean intercropping system at joydebpur. introduction agriculture is facing great challenges to ensure food security, enhance resource use efficiency, and mitigate climate change, which cannot be addressed in isolation (chen et al., 2014). intercropping, as an ancient and traditional cropping system, has a vast potential for realizing sustainable agriculture (knörzer et al., 2009) and it plays important roles in ensuring food and nutrient supply and raising farm income (yin et al., 2017). numerous studies have reported multiple benefits of intercropping systems, such as diversifying crops for market supply (chai et al., 2014), increasing farm income (yang et al., 2018), maximizing land use (dhima et al., 2007), increasing crop yield (li et al., 2001), improving soil quality (cong et al., 2015), and controlling pests and weeds (blaser et al., 2007). some studies have indicated that intercropping system with legume crops could simultaneously reduce n fertilizer and irrigation input and also decrease co2 emissions (yang et al., 2018). intercropping is an important tool for getting higher productivity per unit area of land (mahfuza et al., 2012). intercropping also helps to reduce weed populations, insect pests infestation and risk of complete crop failure (ahmed, 2001; islam et al., 2013). higher productivity from intercropping depends on judicious choice of component crops, suitable planting system or proportion of component crops (begum mailto:luckyshamol6869@gmail.com https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0008 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0021 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0042 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0005 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0040 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0012 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0025 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0009 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0004 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0040 12 begum et al. et al., (2020). research and development work on multiple cropping should be emphasized for sustainable agriculture. maize based intercropping is found profitable and suitable in many countries as well as in bangladesh. maize is c4 plant which has higher yield potential (ahmed, 2001) and greater land use efficiency (bhuiyan, 2001). the newly released hybrids have potential to give yields of 10-12 t ha-1 (rahman et al., 2011). maize is an unbranched and erect cereal crop grown with wide spacing. several short duration and short stature vegetable like dwarf yard long bean (dylb) may be grown in association with hybrid maize. maize is an important cereal crop and dylb is a very popular legume vegetable especially to the urban people with rich in calcium and protein. generally legumes in association with non-legumes helps in not only utilization of the nitrogen being fixed in the current growing season, but also helps in residual nutrients buildup of the soil (kakraliya et al., 2018). farmers often demand for quick return from their crops, so they can get it by growing short duration vegetable crops with long duration crop like maize. moreover, there is no need any trellis or sticks as supporting for dwarf yard long bean plant. it could minimize the production cost of maize + dylb intercropping. therefore, this experiment was conducted to find out suitable planting system of hybrid maize and dylb intercropping for higher productivity, monetary advantage and ensuring food and nutritional security. materials and methods the field experiment was conducted at agronomy research field, bari, gazipur, during kharif-1 season of 2020 and 2021, respectively. treatments included in the experiment were: t1= maize normal row (mnr) +1 row dylb), t2= maize paired row (mpr) + 2 rows dylb, t3= mpr +3 rows dylb, t4= mpr +4 rows dylb, t5= sole maize (60 cm x 20 cm) and t6= sole dylb (40 cm x 25 cm). the experiment was laid out in a randomized complete block design with three replications and the unit plot size was 4.8 m x 5 m. hybrid maize (var. bari hybrid maize-9) and dylb (bari barboti-2) were used in both years. seeds of maize and yard long bean were sown on 10 march, 2020 and 15 march, 2021, respectively, after treated with provex @ 3 g kg-1 seed. fertilizers were applied at the rate of 225-60-120-45-4-1.6 kgha-1 of npksznb (frg, 2018) as urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate and boric acid for sole maize and intercrop. one third of n, whole amount of tsp, mop, gypsum, zinc sulphate and boric acid were applied as basal. remaining 2/3 n was top dressed at 20 and 40 days after sowing (das) of maize. in intercrop, extra n (20 kg ha-1) was applied in two equal splits at 20 and 40 das as side dress to dylb (frg, 2018). sole dylb was fertilized at the rate of 2127-33-9-1.2-1.2 kg ha-1 of npksznb. two third of n and all other fertilizers were applied as basal. rest n was applied at 20 and 40 das. light availability or photo synthetically active radiation (par) was measured by par ceptometer (model – lp-80, accu par, decagon, usa). the par was measured at 15-day intervals from 30 to 105 das at around 11:30 am to 13:00 pm in both years. four readings each of parinc and part were recorded at different spots of each plot. part indicated the light availability above underneath crop (dylb). the proportion of transmitted par (part) was expressed in percentage (ahmed et al., 2010): light availability, part (%) = par t x 100 par inc where, par inc= incident par, and par t = transmitted par data on yield contributing characters of maize were taken from randomly selected 5 plants from each plot. yields of both crops were taken from whole plot area. maize was harvested on 25 june 2020 and 30 june 2021. dylb was harvested five times on 20 april, 30 april, 10 may, intercropping dwarf yard long bean with maize 13 18 may and 24 may 2020 and on 25 april, 05 may, 14 may, 22 may and 01 june 2021. maize equivalent yield was computed by converting yield of intercrops on the basis of prevailing market price of individual crop following the formula of bandyopadhyay (1984) as given below: maize equivalent yield = yim + (yib  pb)/ pm where, yim = yield of intercropped maize, yib = yield of intercropped dylb, pm = market price of maize and pb = market price of dylb. land equivalent ratio (ler) was obtained according to willey (1979) as follows: yield of maize as intercrop yield of dylb as intercrop yield of maize as sole crop yield of dylb as sole crop collected data of both years of both crops were pooled analyzed statistically and the means were adjudged by using lsd at 5% level of significance. cost benefit analysis was also done considering local market price of harvested crops. monetary advantage was evaluated according to shah et al. (1991) as follows: bcr = gross return total cost of production results and discussion light availability irrespective of treatments, availability of light on dylb canopy was almost 100% at earlier growth stage (30 das) and it decreased with the increased of shade produced by maize canopy over the time up to 105 das and then increased up to harvest due to leaf senescence of maize. the flower initiation of dylb started from 30 das. so, flowering was slightly affected with the increased of shade produced by maize canopy over the time up to 105 das in both years. the lowest light availability (50%) on dylb was observed at 105 das in hybrid maize normal row (mnr) + 1 row dylb treatment and the highest was observed in sole dylb treatment and light availability on dylb was more or less similar in mpr + 2 rows dylb, mpr + 3 rows dylb and mpr + 4 rows dylb. among the treatments, light availability on dylb canopy was more in the paired row than normal row of maize throughout the growing period (fig.1). fig.1. light availability on dylb canopy in hybrid maize + dylb intercropping 0 20 40 60 80 100 120 30 45 60 75 90 100 l ig h t a v a il a b il it y ( % ) days after sowing t1=mnr +1 row dylb t2=mpr +2 row dylb t3=mpr +3 row dylb t4=mpr +4 row dylb t6=sole dylb ler = + 14 begum et al. effect of intercropping on maize yield contributing characters and grain yield of maize influenced by intercropping have been presented in table 1. plant height, yield contributing characters (cob length, cob diameter, number of grains cob-1, 1000 grain weight) and grain yield of maize were not significantly differed. although the highest grain yield (8.07tha-1) was recorded in sole maize due to no intercrop competition for growth resources like light, nutrients, moisture and space in sole cropping. this result corroborates with the findings of begum et al. (2020) in maize + garden pea intercropping. the lowest grain yield (7.75 t ha-1 was recorded in mpr + 4 rows of dylb. grain yield in different treatments were attributed to the cumulative effect of yield components. table 1. plant height, yield components and yield of maize in maize +dylb intercropping under different planting system during two kharif -1 seasons (pooled analysis of 2020 and 2021) treatments plant height (cm) cob length (cm) cob diameter (cm) grains /cob (no.) 1000grain wt.(g) grain yield (t/ha) yield decreased over sole maize (%) t1 219 16.5 4.45 511 300 7.99 1.0 t2 219 16.7 4.38 506 290 7.85 2.7 t3 220 16.8 4.36 503 288 7.80 3.3 t4 220 16.8 4.35 500 285 7.75 4.0 t5 214 16.0 4.60 516 305 8.07 t6 lsd(0.05) ns ns ns ns ns ns cv (%) 6.80 4.35 4.07 8.29 5.54 7.53 t1= mnr + 1 row dylb, t2= mpr + 2 rows dylb, t3= mpr + 3 rows dylb, t4= mpr + 4 rows dylb, t5= sole maize and t6=sole dyl effect of intercropping on yield of dylb yield of dylb (pooled of kharif-1 2020 and 2021) in maize + dylb intercropping has been presented in (table 2). yield of dylb was significantly influenced by different planting systems. the highest vegetable /pod yield (6.03tha-1) was found in sole dylb due to no intercrop competition for growth resources and higher number of plants m-2. but in intercropping treatments, light availability for photosynthesis to dylb was depended on degree of shading produced by maize canopy. because, flowering of dylb was slightly affected by insufficient transmitted light (light availability) through the maize canopy in intercrop situation. however, among the intercrop treatments, the highest vegetable yield (3.57 tha-1) was observed in t3 (mpr + 3 rows dylb) treatment followed by t1 (mnr + 1 row dylb) treatment. the lowest vegetable yield was observed in t2 (mpr + 2 row dylb) due to lowest number of plantsm-2. on the other hand, treatment t4 (mnr + 4 rows dylb) having the highest number of plants m-2 failed to produce the highest vegetable/pod yield due to more number of plants m-2 of dylb which was over crowded in t4 treatment. it might be due to t4 had the highest number of plants m-2 (8.89 m-2). intercropping dwarf yard long bean with maize 15 table 2. plant population, vegetable yield of dylb, mey and ler as influenced by maize + dylb intercropping under different planting system (pooled analysis of kharif-1 season 2020 and 2021) treatments plants m-2 (no.) vegetable/pod yield (t ha-1) mey (t ha-1) increased of mey over sole maize (%) ler t1 5.56 2.51 12.17 50.81 1.41 t2 4.44 2.04 11.25 39.41 1.31 t3 6.67 3.57 13.75 70.38 1.56 t4 8.89 2.30 11.58 43.49 1.34 t5 8.07 1.00 t6 10.00 6.03 1.00 lsd (0.05) 1.81 0.78 cv (%) 9.26 8.64 t1= mnr + 1 row dylb, t2= mpr + 2 rows dylb, t3= mpr + 3 rows dylb, t4= mpr + 4 rows dylb, t5= sole maize and t6=sole dylb intercrop productivity land equivalent ratio and mey in maize + dylb intercropping have been presented in table 2. the ler values were more than unity in all the intercropping systems indicated that land was more efficiently utilized under intercropping than sole cropping of maize and dylb. the ler values in the intercrops ranged from 1.31 to 1.56 which indicated 31 to 56 % land utilization increased by intercrop cultivation. the highest ler (1.56) was observed in t3 (mpr + 3 rows dylb) treatment followed by t1 treatment. maize/pea (pisum sativum l.) intercropping systems can also increase ler compared with sole cropping systems in northwest china (yang et al., 2018). on the other hand, mey of all the intercropping systems was higher than sole maize indicating higher productivity of intercropping than sole maize. among the intercropping, the highest mey (13.75 t ha-1) was observed in t3 treatment (mpr + 3 rows dylb) which was 70% higher over sole maize followed by t1treatment. the lowest was observed in t2 (mpr + 2 rows dylb). economic return cost and return analysis of maize + dylb intercropping systems have been presented in table 3. the highest gross return (tk. 247500 ha-1) was observed in t3 treatment (mpr + 3 rows dylb) and it was close to t1 due to higher mey. the gross margin followed the similar trend of gross return. maize /pea (pisum sativum l.) intercropping systems can also increase net income, compared with sole cropping systems in northwest china (yang et al., 2018). the highest cost of production (tk.112500 ha-1) was recorded in t4 treatment which was close to t3 due to involvement of different costs. the highest benefit cost ratio (2.28) was obtained from t3 (mpr + 3 rows dylb) followed by t1 treatment. this result has been supported by the findings of islam et al. (2013) and begum et al. (2020). table 3. costbenefit analysis of hybrid maizedylb intercropping (pooled of kharif-1 2020 and 2021) treatments gross return (tk.ha-1) cost of cultivation (tk.ha-1) gross margin (tk.ha-1) bcr t1 219120 105500 113620 2.08 t2 202500 104500 98000 1.94 t3 247500 108500 139000 2.28 t4 208500 112500 96000 1.85 t5 145260 96000 49260 1.51 t6 180900 95000 85900 1.90 t1= mnr + 1 row dylb, t2= mpr + 2 rows dylb, t3= mpr + 3 rows dylb, t4= mpr + 4 rows dylb, t5= sole maize and t6=sole dylb market price (tk.kg-1): maize= 18, dylb= 30 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0040 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0040 16 begum et al. conclusion two years result revealed that all the intercropping systems showed better productivity than sole maize. hybrid maize paired row (30cm/120cm/30cm x 20cm) + 3 rows dwarf yard long bean and hybrid maize normal row (60cm x 20cm) + 1 row dwarf yard long bean intercropping might be agronomically feasible and economically profitable in joydebpur. references ahmed, f., m.n. islam, m.t. rahman, m.a. jahan and m.s.a. khan. 2010. leaf area index, radiation interception, dry matter production and grain yield of hybrid maize as influenced by plant spacing. bangladesh agron. j. 13(1&2): 51-58. ahmed, f. 2001. analysis of the yield advantage in maize mungbean intercropping with particular references to growth process and micro-environmental condition, phd thesis, dept.agril. sci., kyushu univ., japan. bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. begum, a.a, m.a.k. mian, s.m.a.h.m. kamal, m. karim, r.r. saha and m.a. hossain. 2020. planting system effects on intercropping of gardenpea and sorghum. bangladesh agron. j. 23(2): 59-68. bhuiyan, m.k.a. 2001. productivity and economic feasibility of grain legume intercropped with maize, ms thesis, dept. agron., bangbandhu sheikh mujibur rahman agril. univ., gazipur, bangladesh. blaser, b.c., j. singer and l.r. gibson 2007. winter cereal, seeding rate, and intercrop seeding rate effect on red clover yield and quality. agron. j. 99(3): 723. https://doi.org/10.2134/agronj2006.0247. chai, q., a.z. qin, y.t. gan and a.z. yu. 2014. higher yield and lower carbon emission by intercropping maize with rape, pea, and wheat in arid irrigation areas. agron. for sustainable development, 34(34): 535–543. https://doi.org/10.1007/s13593-013-0161-x. chen, x., z. cui, m. fan, p. vitousek, m. zhao, w. ma, z. wang, w. zhang, x. yan, j. yang, x. deng, q. gao, q. zhang, s. guo, j. ren, s. li, y. ye, z. wang, j. huang and f. zhang. 2014. producing more grain with lower environmental costs. nature, 514(7523): 486–489. https://doi.org/10.1038/natur e13609. cong, w.f., e. hoffland, l. li, j. six, j.h. sun, x.g. bao, f.s. zhang and w. van der werf. 2015. intercropping enhances soil carbon and nitrogen. global change biol. 21: 1715–1726. https://doi.org/10.1111/gcb.12738. dhima, k.v., a.s. lithourgidis, i.b. vasilakoglou and c.a. dordas 2007. competition indices of common vetch and cereal intercrops in two seeding ratios. field crops res. 100(2): 249– 256. https://doi.org/10.1016/j.fcr.2006.07.008. farid, a.t.m. and n.c. shil. 2006. nutrient management for hybrid maize cultivation in bangladesh. in: hybrid maize production technology. training manual. development of hybrid maize research project. plant breeding div., bangladesh agril. res. inst. p.24. frg (fertilizer recommendation guide). 2018. bangladesh agricultural research council (barc), farmgate, dhaka 1215. p. 223. islam, m.n., m. akhteruzzaman and m.s. alom. 2013. split application of inorganic fertilizers in potato (solanum tuberosum l.)-hybrid maize (zea mays l.) intercropping system. bangladesh j. agril. res. 38(3): 447-453. https://doi.org/10.2134/agronj2006.0247 https://doi.org/10.1007/s13593-013-0161-x https://doi.org/10.1038/natur%20e13609 https://doi.org/10.1016/j.fcr.2006.07.008 intercropping dwarf yard long bean with maize 17 kakraliya, s.k., u. singh, a. bohra and k.k. chaudhary. 2018. nitrogen and legumes: a metaanalysis. in: legumes for soil health and sustainable management. pp. 277-314. http://researchgate.net/publication/326227137-nitrogen-and-legumes-a-meta-analysis. knorzer, h., s. graeff-honninger, b. guo, p. wang and w. claupein. 2009. the rediscovery of intercropping in china: a traditional cropping system for future chinese agriculture–a review. climatechange, intercropping, pest control and beneficial microorganisms (pp.13–44). springer. li, l., j. sun, f. zhang, x. li, s. yang and z. rengel. 2001. wheat/maize or wheat/soybean strip intercropping: i. yield advantage and interspecific interactions on nutrients. field crops res. 71: 123–137. https://doi.org/10.1016/s0378 -4290(01)00157-5. mahfuza, s.n., m.n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping different vegetables and spices with pointed gourd. j. expt. biosci. 3(1): 77-82. rohman, m.m., m. amiruzzaman, r. sultana, m.b.m. khaldun, m.n. amin and v.r. bonik. 2011. bhutter jaat, beej utpadon o beboher. bangladesh agril. res. inst., joydebpur, gazipur, bangladesh. p.15-20. shah, n.h., p.k. koul, b.a. khanday and d. kachrov. 1991. production potential and monetary advantage index of maize intercropped with different grain legumes. indian j. agron. 36(1): 23-28. willey, r.w. 1979. intercropping: its performance and research needs. part i. competition and yield advantages. field crops abs. 32: 1-10. yang, c., z. fan and q. chai. 2018. agronomic and economic benefits of pea/maize intercropping systems in relation to n fertilizer and maize density. agron. 8(4): 52. https://doi.org/10.3390/agronomy80 40052. yin, w., q. chai, y. guo, f. feng, c. zhao, a. yu, c. liu, z. fan, f. hu and g. chen. 2017. reducing carbon emissions and enhancing crop productivity through strip intercropping with improved agricultural practices in an arid area. j. cleaner prod. 166: 197–208. https://doi.org/10.1016/j.jclepro.2017.07.211. http://researchgate.net/publication/326227137-nitrogen-and-legumes-a-meta-analysis bangladesh agron. j. 2022, 25(2): 19-29 polyethylene glycol mediated osmotic stress on germination, seedling traits and seed metabolic efficiency of wheat s.k. pramanik, s. sikder and m.a. hasan department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh corresponding e-mail: pramaniksk100@gmail.com (received: 07 august 2022, accepted: 09 october 2022) keywords: polyethylene glycol, osmotic stress, germination, seedling growth, seed metabolic efficiency. abstract germination characteristics, early seedling growth and seed metabolic efficiency of four wheat genotypes (bari gom 28, bari gom 29, baw 1177 and eswyt 29) were evaluated under 15% polyethylene glycol (peg-6000) induced osmotic stress (3 bar). germination characteristics (germination rate, co-efficient of germination and germination vigor index), shoot and root length, shoot and root dry weight, and seed metabolic efficiency decreased under osmotic stress induced by peg than control treatment. but the degree of reduction was different for various wheat genotypes. genotype baw 1177 showed the highest performance in respect to germination and early seedling traits at both control and peg induced osmotic stress than other three genotypes. so, genotype baw 1177 can be considered as relatively drought tolerant genotype. introduction in bangladesh wheat is the second most important cereal crop after rice (barma et al., 2019) grown over an area of 0.33 million hectares with an annual production of about 1.03 million metric tons (bbs, 2020). though wheat is an important cereal crop in bangladesh but its average yield is low (3.09 t ha-1) (bbs, 2020) as compared to that of the advanced countries. at present, the domestic production of the country can only encounter around 20% of total wheat demand (usda, 2018). however, wheat productivity has been declined due to various abiotic stresses over the last two decades particularly drought stress (shao et al., 2008). rising temperature and changing in precipitation pattern leads to increasing incidence and intensity of drought events in the country like bangladesh (khan et al., 2019) where drought employs expressively adverse effects on wheat production in northern and central part of the country (abhinandan et al., 2018). drought stress is responsible for either inhibition or delayed seed germination or seedling establishment (balkan and gençtan, 2013). it has negative effects on the morphological, physiological, and biochemical attributes of the wheat crop (chachar et al., 2016) and it results in a significant reduction in overall production (bilal et al., 2015 and abid et al., 2018). seed germination is a prerequisite and important transition stage for crop plants from seeds to seedlings. the semi-arid regions of the world experience low moisture availability during seed germination of wheat crop (farooq et al., 2019). low moisture availability during seed germination and subsequent growth stages of wheat crop declines final production of wheat as seedling stage of crop plants is highly vulnerable to the water deficit stress (rauf et al., 2007). 20 pramanik et al. seed germination and seedling emergence and/or establishment are important criteria for testing the tolerance of wheat genotypes to various abiotic stresses, particularly, drought stress (hubbard et al., 2012, rauf et al., 2007). evaluation of seed germination under polyethylene glycol (peg-6000) induced drought stress is the most common screening method used to test the drought tolerance of different crop plants during seed germination and early seedling establishment (awan et al., 2021). the use of osmotic substances of high molecular weight such as peg is a common method to test the drought tolerance of crop plants during seed germination and seedling establishment (zarei et al., 2007). several investigations indicated that in vitro screening using peg is one of the reliable approaches to select drought-tolerant genotypes based on germination indices (kocheva and georgiev 2003, shahbazi 2012). therefore, the present study was carried out to test the drought tolerance of four wheat genotypes at early seedling stage through peg-induced osmotic stress. materials and methods experimental site and period the experiment was conducted at crop physiology and ecology laboratory, hajee mohammad danesh science and technology university, dinajpur, bangladesh during november, 2021. experimental design and treatments four wheat genotypes were evaluated under two growing conditions control and 15% peg induced drought stress following completely randomized design with three replications. peg solution was prepared by dissolving calculating amount of peg (151.5 g / 1000 ml) in tap water as described by michel (1983). normal tap water was used as control treatment. characteristics of the wheat genotypes: bari gom 28: high yielding variety, duration: 105-110 days, plant height: 95-100 cm, 1000grain weight: 35-40 g, grain yield: 3.5-5.4 t/ha, tolerant to terminal heat stress, resistant to leaf rust and ug99 race of stem rust, moderately tolerant to bipolaris leaf blight, moderately susceptible to wheat blast and fit to the rice-wheat cropping system bari gom 29: high yielding variety, duration: 102-108 days, plant height: 95-100 cm, 1000grain weight: 44-48 g, grain yield: 4.0-5.0 t/ha, tolerant to terminal heat stress, and moderately susceptible to wheat blast baw 1177: advanced line of bangladesh wheat and maize research institute (bwmri) eswyt 29: advanced line of bwmri. spring bread wheat adapted to mega-environment 1 i.e. the optimally irrigated, low rainfall areas with an average minimum temperature in the coolest quarter between 3 and 11°c. (me1): seed placement and data collection on germination and seedling traits twenty-five seeds of each genotype were placed on filter paper soaked by treatment solution and distilled water according to treatment in 11 cm diameter sterilized petri dish. the 10 ml treatment solution or distilled water was poured on the filter paper and afterwards the solution or distilled water was given according to the needs. seedlings were allowed to grow up to 7 days after placement of germination. germination was counted at 24-hours interval starting from 72h after of seed set and continued up to 7th day. a seed was considered germinated as plumule and radicle came out and was larger than 2 mm long. the rate of germination was calculated according to krishnasamy and seshu, (1990) and co-efficient of germination and vigor index polyethylene glycol mediated osmotic stress on germination, seedling traits of wheat 21 were calculated using the formulae (copeland, 1976). at 7th days after seed placement for germination, five seedlings from each petri dish were sampled for shoot and root length. then shoot, root and remaining seeds were dried separately at 70oc for 72h in an electric oven (modele28# 03-54639, binder, germany) and weight were recorded with an electrical balance (modeland ek300i). the mean length and dry weight were calculated for each treatment combination. calculation of amount of seed material respired (smr) and seed metabolic efficiency (sme) smr was calculated as: smr = sdw – (shw + rtw + rsw), where, sdw = seed dry weight before germination, shw = shoot dry weight, rtw = root dry weight and rsw = remaining seed dry weight. seed metabolic efficiency was calculated using the formula (rao and sinha, 1993). the relative performance regarding different germination and seedling traits was calculated as described by asana and william (1965) using the following formula relative performance (%) = (variable measured under stress condition ÷ variable measured under normal condition) × 100 calculation of drought tolerance/resistance indices the drought tolerance/resistance indices based on different traits were calculated using the following formulas: i) tolerance (tol) = yp-ys (rosielle and hamblin 1981); where yp and ys are the mean values of genotypes under non-stress and stress conditions, respectively; the genotypes with low values of this index are more stable in two different conditions. ii) drought tolerance index (dti) = ys ÷ yp (goudarzi and pakniyat 2008); the genotypes with high value of this index will be more tolerant to stress. iii) drought sensitivity index (dsi) = (yp -ys) ÷ yp (farshadfar and javadinia 2011); the genotypes with low value of this index will be more desirable. iv) mean productivity (mp) (ys yp) ÷ 2 (rosielle and hamblin 1981); the genotypes with high value of this index will be more desirable. statistical analyses of data the experimental data were analyzed by partitioning the total variance using stata program (small stata 12.0) and the means were compared by tukey’s test at 5% level of probability. results and discussion germination characteristics the interaction effect of growing conditions and wheat genotypes significantly influenced the germination rate and germination vigor index but insignificant in co-efficient of germination (table 1). all the genotypes showed higher germination rate at control (84.83 to 98.48%) as compared to peg induced osmotic stress condition (64.11 to 79.12%). under stress condition, baw 1177 attained the highest germination rate (79.12%), whereas eswyt 29 had the lowest germination rate (64.11%). in relative performance, bari gom 29 showed the highest performance (87.49%) while eswyt 29 had the lowest performance (70.33%) and rest two genotypes bari gom 28 and baw 1177 showed moderate performance (77.12 and 80.34%, respectively). 22 pramanik et al. co-efficient of germination was found higher at control with a range from 35.49% in bari gom 29 to 36.44% in baw 1177 as compared to peg induced osmotic stress condition with a range from 33.73% in bari gom 29 to 34.91% in baw 1177. considering relative performance highest performance was found in baw 1177 (95.80%), while bari gom 28 had the lowest performance (94.35%). at control condition, the highest germination vigor index was found in baw 1177 (33.83), whereas the lowest in bari gom 29 (30.71). the moderate germination vigor index (32.44) was found in both bari gom 28 and eswyt 29. under stress condition, again baw 1177 attained the highest germination vigor index (27.15), while eswyt 29 had the lowest (23.87) which was statistically similar with bari gom 28 (24.02) and bari gom 29 (23.94). in relative performance, genotype baw 1177 showed the highest performance (80.25%), whereas eswyt 29 the lowest performance (73.58%). table 1. effects of polyethylene glycol induced osmotic stress (-3 bar) on germination characteristics of wheat genotypes genotypes growing conditions germination rate co-efficient of germination germination vigor index % rp (%) rp (%) rp (%) bari gom 28 control 96.57a 77.12 36.10 94.35 32.44a 74.04 stress 74.47b 34.06 24.02d bari gom 29 control 84.83a 87.49 35.49 95.04 30.71b 77.96 stress 74.22b 33.73 23.94d baw 1177 control 98.48a 80.34 36.44 95.80 33.83a 80.25 stress 79.12b 34.91 27.15c eswyt 29 control 91.15a 70.33 36.19 95.50 32.44a 73.58 stress 64.11b 34.56 23.87d cv (%) 1.34 1.96 1.44 in a column, means followed by the same letter(s) did not differ significantly at p ≤ 5% level by tukey test. rp = relative performance. a decline in germination percentage under moisture stress has been reported in wheat by sharma et al. (2022). they observed that the germination rate was reduced with the increment of water deficit stress but the degree of reduction in rate of germination was not similar for all wheat genotypes. development at the germination stage have been adopted a suitable growth stage for testing the drought stress tolerance in wheat. it could be assumed that the presence of increased concentrations of osmotic potential during the growth of germination stage inhibits the developmental traits and survival of wheat. differential degree of sensitivity in germination characteristics to peg induced water stress among the wheat genotypes may be due to genetic variability of wheat to water stress condition. mahpara et al. (2022) bilgili et al. (2019) and rana et al. (2017) similarly detected significant differences in germination characteristics of wheat genotypes under peg induced water deficit stress. early seedling growth early seedling growth (shoot length, root length, shoot dry weight, and root dry weight) of 7 days old seedling was significantly influenced by the interaction effect of growing conditions and wheat genotypes (table 2 and fig. 1). the longest shoot length was found at control with a range from 3.44 cm in bari gom 28 to 3.82 cm in baw 1177 as compared to stress condition with a range from 1.36 cm in bari gom 29 to 2.72 cm in baw 1177. at control condition, the longest shoot length (3.82 cm) was found in baw 1177 followed by 3.79 cm in eswyt 29 and 3.52 cm in bari gom 29, whereas the shortest shoot length (3.44 cm) was polyethylene glycol mediated osmotic stress on germination, seedling traits of wheat 23 found in bari gom 28. under stress condition, baw 1177 produced the highest shoot length (2.72 cm) followed by bari gom 28 (2.19 cm), while bari gom 29 had the lowest shoot length (1.36 cm) which was statistically identical with eswyt 29 (1.37 cm). normal tap water peg solution fig. 1. seven days old seedlings of wheat genotype grown under normal tap water and peg solution. considering relative performance, baw 1177 performed highest (71.20%), whereas eswyt 29 performed lowest (36.14%) followed by bari gom 29 (38.63%). moderate performance (63.66%) was found in bari gom 28. at control condition, baw 1177 produced the longest root (7.28 cm) followed by bari gom 29 (7.06 cm) and eswyt 29 (7.21 cm), whereas bari gom 28 produced the shortest root (6.18 cm). table 2. effects of polyethylene glycol induced osmotic stress (-3 bar) on early seedling growth of 7 days old seedlings of wheat genotypes genotypes growing conditions shoot length root length shoot dry weight root dry weight cm rp (%) cm rp (%) mg rp (%) mg rp (%) bari gom 28 control 3.44a 63.66 6.18b 78.64 0.030bc 76.66 0.040b 70.00 stress 2.19b 4.86c 0.023d 0.028d bari gom 29 control 3.52a 38.63 7.06a 64.44 0.033ab 72.72 0.035c 71.42 stress 1.36c 4.55c 0.024d 0.025e baw 1177 control 3.82a 71.20 7.28a 82.14 0.035a 77.14 0.045a 73.33 stress 2.72b 5.98b 0.027cd 0.033c eswyt 29 control 3.79a 36.14 7.21a 64.07 0.031abc 58.06 0.038bc 52.63 stress 1.37c 4.62c 0.018e 0.020e cv (%) 6.61 6.16 6.14 2.99 in a column, means followed by the same letter(s) did not differ significantly at p ≤ 5% level by tukey test. rp = relative performance. under stress condition, baw 1177 produced the longest root (5.98 cm), whereas bari gom 29 had the shortest root (4.55 cm). but under stress condition, all the genotypes produced statistically similar root length. in relative performance, it was found that genotype baw 1177 showed higher relative root length (82.14%) compared to others genotypes (78.64% in bari gom 28, 64.44% in bari gom 29 and 64.07% in eswyt 29). results showed that shoot dry weight was decreased at water stress condition. minor variations among the wheat genotypes both under control (0.030 mg to 0.035 mg) and peg induced water deficit (0.018 mg to 0.027 mg) conditions were observed. under control condition, baw 1177 attained the highest shoot dry weight (0.035 mg) followed by bari gom 29 (0.033 mg) and eswyt 29 (0.031 mg), whereas bari gom 28 had the lowest shoot dry weight (0.03 mg). 24 pramanik et al. under water stress condition, eswyt 29 showed the lowest shoot dry weight (0.018 mg) and highest shoot dry weight was found in baw 1177 (0.027 mg) followed by bari gom 28 (0.023 mg) and bari gom 29 (0.024 mg). in relative performance, it was found that the genotype baw 1177 and bari gom 28 showed the higher relative value (77.14 and 76.66%), whereas eswyt 29 attained the lowest relative value (58.06%) in shoot dry weight. bari gom 29 showed moderate performance (72.72%) compared to others. results showed that root dry weight was decreased at stress condition. there existed minor variations among the wheat genotypes both at control (0.035 mg to 0.045 mg) and peg induced osmotic stress (0.024 mg to 0.033 mg) conditions. under control condition, baw 1177 showed the highest root dry weight (0.045 mg), whereas bari gom 29 had the lowest (0.035mg) and it was at par with eswyt 29 (0.038 mg). under osmotic stress condition, eswyt 29 showed the lowest root dry weight (0.024 mg) followed by bari gom 29 (0.025 mg) and highest root dry weight was found in baw 1177 (0.033 mg). in relative performance, genotype baw 1177 showed the higher relative value (73.33%) and eswyt 29 lower relative value (52.63%). moderate performance was found in bari gom 29 (71.42%) followed by bari gom 28 (70.00%). reduction in seedling growth is the result of restricted cell division and enlargement, as drought stress directly reduces growth by decreasing cell division and elongation (kramer, 1983). reduction in shoot and root length might be due to less water absorption and decrease in external osmotic potential created by peg (kaydan and yagmur, 2008). significant reduction in term of shoot length, root length and seedling dry weight among the genotypes might be attributed to their differential response in term of tolerance level to moisture stress. these results of the present study are parallel to the findings of faisal et al. (2019) mahpara et al. (2022) and sharma et al. (2022). seed metabolic efficiency (sme) the significant variation of sme of four wheat genotypes at different growing conditions is presented in table 3. at control condition, genotype baw 1177 attained the maximum sme (3.36 g g-1) which was statistically identical with eswyt 29 (2.91 g g-1), whereas lowest sme in bari gom 29 (1.41 g g-1) followed by bari gom 28 (1.47 g g-1). at peg induced osmotic stress, genotype baw 1177 attained the highest sme (2.4 g g-1), whereas eswyt 29 the lowest sme (0.65 g g-1) followed by bari gom 29 (0.72 g g-1) and bari gom 28 (0.96 g g-1). stress condition reduced the sme in all genotypes but the magnitude of reduction in sme was not similar in all genotypes. in relative performance, highest performance was performed by baw 1177 (71.43%) and lowest performance by eswyt 29 (22.33%). table 3. effects of polyethylene glycol induced osmotic stress (-3 bar) on seed metabolic efficiency of wheat genotypes genotypes growing conditions seed metabolic efficiency g g-1 relative performance (%) bari gom 28 control 1.47b 65.30 stress 0.96c bari gom 29 control 1.41b 51.06 stress 0.72c baw 1177 control 3.36a 71.43 stress 2.40a eswyt 29 control 2.91a 22.33 stress 0.65c cv (%) 6.15 in a column, means followed by the same letter(s) did not differ significantly at p ≤ 5% level by tukey test. polyethylene glycol mediated osmotic stress on germination, seedling traits of wheat 25 the reduction in sme at water stress condition suggested that at water stress, substrate respiration was not linked to building useful plant parts (shoot and root) and could lead to thermal dissipation of respiratory energy by an alternate oxidase pathway or cyanide resistant pathway. reduction in sme may be attributed to inability to accumulate respiratory product to wheat seedlings. the results are in accordance of findings of sikder et al. (2010). they concluded that seed metabolic efficiency of wheat genotypes was affected to a greater extent under stress condition. correlation analysis among different germination and early seedling traits correlation analysis among different germination and early seedling traits in this investigation presented in table 4 indicates that all the traits maintained a significant positive relation with each other. table 4. correlations (pearson) among the different germination and seedling traits of wheat genotypes germination rate co-efficient of germination germination vigor index shoot length root length shoot dry weight root dry weight seed metabolic efficiency germination rate 1.000** co-efficient of germination 0.926** 1.000** germination vigor index 0.889** 0.972** 1.000** shoot length 0.835** 0.902** 0.891** 1.000** root length 0.833** 0.868** 0.880** 0.923** 1.000** shoot dry weight 0.799** 0.780** 0.780** 0.872** 0.850** 1.000** root dry weight 0.9311** 0.9210** 0.8795** 0.9014** 0.8345** 0.8855** 1.0000** seed metabolic efficiency 0.768** 0.649** 0.556** 0.533* 0.561** 0.647** 0.756** 1.000** ** and * indicate significant at the 1% and 5% probability level, respectively. relationship of different seedling traits with seed metabolic efficiency different seedling attributes (shoot length, root length, shoot dry weight and root dry weight) of wheat genotypes maintained a positive linear relationship with seed metabolic efficiency (fig. 2). the results revealed that the genotype with higher sme produced higher shoot length, root length, shoot dry weight and root dry weight, while the genotype with lower sme provided lower values of that attributes. it indicated that the seedling traits of wheat genotypes increased with the increment of sme and decreased with the decreasing of sme. the higher shoot length, root length, shoot dry weight and root dry weight resulted from higher sme probably due to the genotype with higher sme links adequate substrate respiration to build useful plant parts (shoot and root). it also might be due to the more ability of genotype with higher sme to accumulate respiratory product to wheat seedlings. drought tolerance/resistance indices drought tolerance, drought tolerance index, drought sensitivity index and mean productivity of wheat genotypes based on different germination and early seedling traits are presented in table 5. variation in different indices observed in different wheat genotypes indicating different levels of drought tolerance under peg induced osmotic stress. the genotype with the least tol and dsi and the highest dti, and mp showed more tolerance to stress condition than the other 26 pramanik et al. genotypes. farshadfar et al. (2013) and hooshmandi (2019) used tol, dti, dsi and mp as a tolerance criterion for wheat genotypes in stress conditions. fig. 2. linear relationship of different seedling traits with seed metabolic efficiency. table 5. drought tolerance /resistance indices of wheat genotypes based on different germination and seedling traits wheat genotypes tolerance/resistance indices germination and seedling traits gr cg gvi sl rl sdw rdw sme bari gom 28 tol 22.10 2.04 8.42 1.25 1.32 0.007 0.012 0.51 dti 0.77 0.94 0.74 0.64 0.79 0.770 0.700 0.65 dsi 0.23 0.06 0.26 0.36 0.21 0.230 0.300 0.35 mp 85.52 35.08 28.23 2.82 5.52 0.027 0.034 1.22 bari gom 29 tol 10.61 1.76 6.77 2.16 2.51 0.009 0.010 0.69 dti 0.87 0.95 0.78 0.39 0.64 0.730 0.710 0.51 dsi 0.13 0.05 0.22 0.61 0.36 0.270 0.290 0.49 mp 79.53 34.61 27.33 2.44 5.81 0.029 0.030 1.07 baw 1177 tol 19.36 1.53 6.68 1.10 1.30 0.008 0.012 0.96 dti 0.80 0.96 0.80 0.71 0.82 0.770 0.730 0.71 dsi 0.20 0.04 0.20 0.29 0.18 0.230 0.270 0.29 mp 88.80 35.68 30.49 3.27 6.63 0.031 0.039 2.88 eswyt 29 tol 27.04 1.63 8.57 2.42 2.59 0.013 0.018 2.26 dti 0.70 0.95 0.74 0.36 0.64 0.580 0.530 0.22 dsi 0.30 0.05 0.26 0.64 0.36 0.420 0.470 0.78 mp 77.63 35.38 28.16 2.58 5.92 0.025 0.031 1.78 gr = germination rate, cg = co-efficient of germination, gvi = germination vigor index, sl = shoot length, rl = root length, sdw = shoot dry weight, rdw = root dry weight, sme = seed metabolic efficiency, tol =tolerance, dti = drought tolerance index, dsi = drought sensitivity index, mp = mean productivity polyethylene glycol mediated osmotic stress on germination, seedling traits of wheat 27 conclusion based on different germination and early seedling traits evaluated as well as drought tolerance indices, genotype baw 1177 was found comparatively drought tolerant, whereas eswyt 29 was found drought susceptible and bari gom 29 and bari gom 28 were found moderately drought tolerant. references abhinandan, k., l. skori, m. stanic, n. hickerson, m. jamshed, m.a. samuel. 2018. abiotic stress signaling in wheat-an inclusive overview of hormonal interactions during abiotic stress responses in wheat. front. plant sci. 9: 734. abid, m., s. ali, l.k. qi, r. zahoor, z. tian, d. jiang, j.l. snider and t. dai. 2018. physiological and biochemical changes during drought and recovery periods at tillering and jointing stages in wheat (triticum aestivum l.). sci. rep. 8: 4615. asana, r.d. and r.f. williams. 1965. the effect of temperature stress on grain development in wheat. aust. j. agril. res. 16(1): 1-13. awan, s.a., i. khan, m. rizwan, x. zhang, m. brestic, a. khan, et al. 2021. exogenous abscisic acid and jasmonic acid restrain polyethylene glycol-induced drought by improving the growth and antioxidative enzyme activities in pearl millet. physiol. plant 172: 809-819. balkan, a. and t. gençtan. 2013. effect of osmatic stress on germination and early growth in bread wheat (triticum aestivum). j. tekirdag agril. faculty 10(2): 44-52. barma, n.c.d., a. hossain, m.a. hakim, k.a. mottaleb, m.a. alam, m.m. reza and m.m. rohman. 2019. progress and challenges of wheat production in the era of climate change: a bangladesh perspective. in wheat production in changing environments. springer, singapore pp. 615-679. bbs. 2020. yearbook of agricultural statistics 2019, bangladesh bureau of statistics (bbs), statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka bangladesh. bilal, m., i. iqbal, r.m. rana, u.r. shoaib, q. haidery, f. ahmad, a. ijaz and h.m.i. umar. 2015. comprehensive review of effects of water stress and tolerance in wheat (triticum aestivum l.). trop. plant res. 2: 271-275. chachar, m.h., n.a. chachar, q. chachar, s.m. mujtaba, s. chachar and z. chachar. 2016. physiological characterization of six wheat genotypes for drought tolerance. int. j. res. granthaalayah 4: 184-196. copeland, l.o. 1976. principles of seed science and technology (burgess publication company, minneapolis, minnesota), p. 164. didem, b.g., a.t.a.k. mehmet and m.a.v.i. kazım. 2019. effects of peg-induced drought stress on germination and seedling performance of bread wheat genotypes. yyu j. agril. sci. 29(4): 765-771. farooq, s. h. onen, c. ozaslan, c.c. baskin and h. gunal. 2019. seed germination niche for common ragweed (ambrosia artemisiifolia l.) populations naturalized in turkey. south afric. j. bot. 123: 361-371. farshadfar, e. and j. javadinia 2011. evaluation of chickpea (cicer arietinum l.) genotypes for drought tolerance. seed and plant improv. j. 27(4): 517-537 (in persian). 28 pramanik et al. farshadfar, e., r. mohammadi, m. farshadfar and d. shokouh. 2013. relationships and repeatability of drought tolerance indices in wheat-rye disomic addition lines. aust. j. crop sci. 7(1): 130-138. goudarzi, m. and h. pakniyat 2008. evaluation of wheat cultivars under salinity stress based on some agronomic and physiological traits. j. agril. soc. 4: 35-38. hooshmandi, b. 2019. evaluation of tolerance to drought stress in wheat genotypes. artículos de investigación 37(2): 37-43. hubbard, m., j, germida and v. vujanovic. 2012. fungal endophytes improve wheat seed germination under heat and drought stress. botany 90: 137-149. kaydan, d. and m. yagmur. 2008. germination, seedling growth and relative water content of shoot in different seed sizes of triticale under osmotic stress of water and nacl. afric. j. biotech. 7(16): 2862-2868. khan, n., s. shahid, t. ismail, k. ahmed and n. nawaz. 2019. trends in heat wave related indices in pakistan. stochastic environmental research and risk assessment. 33: 287-302. kocheva, k. and g. georgiev. 2003. evaluation of teh reaction of two contrasting barley (hordeum vulgare l.) cultivars in response to osmotic stress with peg 6000. bulg. j. plant physiol. 290-294. kramer, p.j. 1983. water relation of plants. academic press, orlando, p. 342. krishnasamy, v. and d.v. seshu. 1990. germination after accelerated aging and associated characters in rice varieties. seed sci. tech. 18: 353. mahpara, s., a. zainab, r. ullah, s. kausar, m. bilal, m.i. latif et al. 2022. the impact of peg induced drought stress on seed germination and seedling growth of different bread wheat (triticum aestivum l.) genotypes. plos one 17(2): e0262937. michel, b.e. 1983. evaluation of the water potentials of solutions of polyethylene glycol 8000. plant physiol. 72: 66. rana, m.s., m.a. hasan, m.m. bahadur and m.r. islam. 2017. effect of polyethylene glycol induced water stress on germination and seedling growth of wheat (triticum aestivum). the agriculturists 15(01): 81-91. rao, d.g. and s.k. sinha. 1993. efficiency of mobilization of seed reserves in sorghum hybrids and their parents as influenced by temperature. seed res. 21: 97. rauf, m., m. munir, m. ul hassan, m. ahmad and m. afzal. 2007. performance of wheat genotypes under osmotic stress at germination and early seedling growth stage. afric. j. biotech. 6: 971-975. rosielle, a.a. and j. hamblin 1981. theoretical aspects of selection for yield in stress and non-stress environments. crop sci. j. 21: 943-946. shahbazi, f.a. 2012. study on the seed susceptibility of wheat (triticum aestivum l.) cultivars to impact damage. j. agric. sci. tech. 14(3): 505-512. shao, h.b., l.y. chu, c.a. jaleel and c.x. zhao. 2008. water deficit stress induced anatomical changes in higher plants. comptes rendus biologies 331: 215-225. sharma, v., a. kumar, a. chaudhary, a. mishra, s. rawat, y.b. basavaraj, v. shami and p. kaushik. 2022. response of wheat genotypes to drought stress stimulated by peg. stresses 2: 26-51. polyethylene glycol mediated osmotic stress on germination, seedling traits of wheat 29 sikder, s. and n.k. paul 2010. study on influence of temperature regimes on germination characteristics and seed reserves mobilization in wheat. afric. j. plant sci. 4(10): 401-408. summiya, f., s.m. mujtaba, asma and w. mahboob. 2019. polyethylene glycol mediated osmotic stress impacts on growth and biochemical aspects of wheat (triticum aestivum l.) j. crop sci. biotech. 22(3): 213223. usda. 2018. foreign agricultural service. bangladesh, grain and feed annual. 2018. retrieved from https ://gain.fas.usda.gov/. accessed on 31 jan 2019. zarei, l., e. farshadfar, r. haghparast, r. rajabi and m.m.s. badieh. 2007. evaluation of some indirect traits and indices to identify drought tolerance in bread wheat (triticum aestivum l.). asian j. plant sci. 6(8): 1204-1210. bangladesh agron. j. 2021, 24(1): 119-128 growth and yield of wheat as influenced by micronutrients under water deficit condition m. a. tithi1, m. a. mannan1, m. a. r. khan1and m. m. rahman2 1department of agronomy and 2department of soil science bangabandhu sheikh mujibur rahman agricultural university, bangladesh corresponding e-mail: mannanbsmrau@yahoo.com (received: 25 april 2021, accepted: 10 june 2021) keywords: zn, fe, application strategy, drought tolerance. abstract crop productivity is greatly affected by drought stress. in order to evaluate the effects of zn and fe micronutrients on growth and yield of wheat (triticum aestivum l.) variety bari gom 29, a pot experiment was conducted at the agronomy research field of bangabandhu sheikh mujibur rahman agricultural university during november 2018 to march 2019. two water regimes i.e. control (80% of field capacity) and drought (40% of field capacity) were maintained throughout the growing season. micronutrients zn and fe viz. i) znso4.7h2o and fe3so4.7h2o @22 kgha-1were applied in soil before sowing; ii) znso4.7h2o solution and fe3so4.7h2o solution @ 5% of each were applied as foliar spray at flowering stage following completely randomized design (crd) with three replications. the results indicated that drought stress affected negatively wheat growth such as plant height, fresh weight of leaf, stem, root and total weight of plant as well as yield. zn and fe mitigate the drought effects in wheat which ultimately improve the growth and the yield. among the micronutrients, fe (fe3so4.7h2o) was found more effective when it was applied as foliar spray @ 5% solution for increasing the growth and yield of wheat under water deficit stress condition. introduction wheat (triticum aestivum l.) is economically one of the most important cereal crops in the world. wheat, next to rice is the staple food of the people in bangladesh. less rainfall is the main constraint for wheat production in the arid/semi-arid regions, and it is reducing 50% crop yield (wang et al., 2003). climate change is associated with global warming that affects climatic variability. drought is the environmental stress that negatively affects the growth, development and productivity of a crop (kamal et al., 2010). various techniques are being used to protect plants from the adverse effects of abiotic stresses like drought, which include exogenous supplementations of silicon, nitric oxide, growthpromoting hormones, enzymes, and nutrient management (saxena and shekhawat, 2013). among the remedies for abiotic stress, nutrient regulations or management are considered as the cost effective and ecofriendly techniques (tripathi et al., 2017). in addition, studies also showed that an exogenous supply of nutrients plays a crucial role in the enhancement of plant tolerance against various abiotic stresses. some nutrients such as calcium (ca), magnesium (mg), sulfur (s), zinc (zn), and iron (fe) have shown significant results when they are examined under salinity, drought, and heavy-metal stresses (nazar et al., 2012). currently, the application of fe as a nutrient supplement and its role in imparting tolerance to plants against abiotic stresses are 120 tithi et al. gaining attention as an area of research. tabatabai et al. (2015) reported that zinc sulfate played a more important role in stomata regulation and ion balance in plant systems to reduce the tension of drought. considering above facts, the objectives of the present study were to investigate the effectiveness of zinc (zn) and iron (fe) micronutrients in reducing the adverse effects of drought stress in wheat in relation to growth and yield, and to identify the effective application method of zinc (zn) and iron (fe) for improving the drought tolerance potential of wheat. materials and methods site and soil description: a pot experiment was conducted under semi-controlled environment (inside screen house) at department of agronomy, bangabandhu sheikh mujibur rahman agricultural university (bsmrau), gazipur, bangladesh during november 2018 to march 2019. the experimental site is in the center of madhupur tract (24.09o n latitude and 90.26o e longitude) at 8.4 m above the sea level. plastic pots (30 cm length and 24 cm diameter) were used in the experiment which was filled with soil, holds about 28% moisture at field capacity (fc). the soil of the pot was fertilized uniformly with 0.9, 0.8 and 0.8 g urea, triple super phosphate and muriate of potash corresponding to 160-150-150 kg urea, triple super phosphate and muriate of potash per hectare, respectively (barc,2012). the experimental soil was sandy loam with ph 6.93, soil organic carbon 0.61%, total n 0.070%, available p 0.06 mg 100 g-1 , exchangeable k 0.79 cmolc kg-1 dry soil, available s 10.00 g g-1, cec 13.05 cmolc kg-1 dry soil and ec 0.04 dsm-1. air temperature, relative humidity and rainfall in the period of experimentation are presented in table 1. table 1. air temperature, relative humidity and rainfall in the period of experimentation month air temperature (ºc) relative humidity (%) total rainfall(mm) maximum minimum average november, 2018 29.22 17.22 23.22 86.73 71.10 december, 2018 25.50 13.10 19.30 86.65 21.69 january, 2019 26.61 11.61 19.22 85.42 0.00 february, 2019 27.82 14.34 20.26 85.36 46.10 march, 2019 27.88 14.43 24.5 85.27 51.32 source; department of agricultural engineering, bsmrau (http://bsmrau.edu.bd/age/weather-data/) treatments and experimental design: the experiment was designed at completely randomized design (crd) with three replications. ten seeds of bari gom 29 were sown in each pot and light irrigation was given by using the watering can to ensure uniform germination. after germination thinning were done remaining 3 healthy seedlings in each pot. the treatment combinations were: c=control (80% of field capacity), d1=drought (40% of field capacity), d2=drought+ znso4.7h2o@22kgha-1 (11 mgkg-1 soil), d3=drought+ fe3so4.7h2o @22kgha-1 (11 mgkg-1 soil), d4=drought+ znso4.7h2o + fe3so4.7h2o @22kgha-1 (11 mgkg-1 soil)of both, d5=drought+ znso4.7h2o @ 5%(5 g 100 ml-1 water) as foliar spray, d6=drought+ fe3so4.7h2o @ 5% (5 g100 ml-1 water)as foliar spray, d7=drought+ znso4.7h2o + fe3so4.7h2o @ 5%(5 g100 ml-1 water) of both foliar spray. znso4.7h2o and fe3so4.7h2o were applied in soil before sowing and solutions treatments were applied as foliar spray at flowering stage. moisture level in pot soil was measured daily using portable digital moisture meter (pogo soil sensor ii, stevens, usa) and required amount of water was added daily to reach 80% of field capacity and 40% of field capacity for control and drought treatments, respectively. http://bsmrau.edu.bd/age/weather mailto:znso4.7h2o@22kg growth and yield of wheat as influenced by micronutrients 121 data recorded: growth parameters like plant height, fresh weight of leaf, stem, root and total weight of plant were recorded at 15 and 30 days after flowering. yield and yield contributing parameters were recorded at maturity after harvest. data analysis: the recorded data were statistically analyzed by “crop stat 7.2” software to examine the significant variation of the results due to different treatments. the treatment means were compared by least significant difference (lsd) test at 5% level of significance (gomez and gomez, 1984). microsoft excel 2013 software program was used wherever appropriate to perform statistical analysis. results and discussion growth attributes plant height of wheat variety barigom 29 varied appreciably under drought stress as presented in figure 1. though plant height is genetically controlled, drought stress also played a significant role in its regulation. plant height showed an increasing trend but drought stress significantly reduced the rate of increase in plant height of the wheat variety. at 15 days after flowering, in control condition the plant height was 58.72 cm and in drought condition the plant height was 49.55 cm. application of zn and fe micronutrients increased the plant height under drought stress and the highest plant height (56.26 cm) was recorded when fe3so4.7h2o was applied @5% solution as foliar spray followed by fe3so4.7h2o @ 22 kgha-1(54.27 cm), znso4.7h2o @ 22 kgha-1 (53.40 cm), znso4.7h2o @ 5% c= control, d1= drought, d2=drought+znso4.7h2o @ 22 kgha-1, d3= drought+fe3so4.7h2o @ 22 kgha-1, d4=drought+ znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both, d5=drought+ znso4.7h2o @ 5% solution as foliar spray, d6= drought+ fe3so4.7h2o @5% solution as foliar spray, d7= drought+ znso4.7h2o+ fe3so4.7h2o @ 5 % solution of both as foliar spray fig. 1. effect of zn and fe on plant height of wheat under drought stress at 15 and 30 days after flowering. bars indicate (±se). 0 10 20 30 40 50 60 70 80 90 c d1 d2 d3 d4 d5 d6 d7 p la n t h ei g h t (c m ) treatments 15 days after flowering 30 days after flowering 122 tithi et al. solution as foliar spray (53.38 cm), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (52.27 cm) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (51.51 cm). on the other hand, at 30 days after flowering, in control condition the plant height was 83.11 cm and in drought condition it was 67.89 cm. under drought condition the highest plant height (77.89 cm) was recorded when fe3so4.7h2o was applied @5% solution as foliar spray and the lowest was recorded in 70.59 cm when znso4.7h2o+ fe3so4.7h2o was applied @ 5% solution of both as foliar spray. the decrease in plant height might be due to decrease in relative turgidity and dehydration of protoplasm which in associated with the loss of turgor and reduce expansion of cell and cell division (arnon, 1972). soil application and foliar spray of fe alone or in combination with other micronutrients increase plant height of wheat reported by abbas et al. (2009). monjezi et al. (2013) was found that drought stress on wheat reduced the plant height, but with zn application significantly increased the plant height. these findings agreed with those of bayoumi et al. (2008) in wheat, manivannan et al. (2007) in sunflower those reported reduction in plant height under drought stress and found positive effects of micronutrients on plant height. drought stress exerted significant effect on leaf fresh weight of bari gom 29 as shown in table 2. leaf fresh weight showed an increasing trend but drought stress appreciably reduced the rate of increase in leaf fresh weight of the wheat variety. it was observed that in control condition the leaf fresh weightplant-1 was 3.57g and in drought condition it was 2.15gat 15 days after flowering. zn and fe micronutrients tended to reduce the adverse effect of drought stress in relation to leaf fresh weight and the highest leaf fresh weight (3.40g) was recorded when fe3so4.7h2o was applied @5% solution as foliar spray followed by znso4.7h2o @ 5% solution as foliar spray (2.58g), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (2.57g), znso4.7h2o @ 22 kgha-1(2.42g), fe3so4.7h2o @ 22 kgha-1(2.40g) and the lowest was recorded in fe3so4.7h2o @ 5% solution of both as foliar spray (2.37 g). consequently, at 30 days after flowering, in control condition the leaf fresh weightplant-1 was 3.98g and in drought condition the leaf fresh weightplant-1 was 2.22g. the highest leaf fresh weight plant-1 (3.40g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by fe3so4.7h2o @ 22 kgha-1(2.72 g), znso4.7h2o @ 5% solution as foliar spray (2.71 g), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (2.64 g), znso4.7h2o @ 22 kgha-1(2.50 g) and the lowest was recorded in fe3so4.7h2o @ 5% solution of both as foliar spray (2.57 g) under drought condition. it was found that drought stress reduced the leaf fresh weightplant-1 but application of zn and fe increases the leaf fresh weight in all of the cases. reduction in leaf fresh weight might be due to loss of leaf turgidity under drought (salsinha et al., 2020), which was maintained at a satisfactory level when micronutrients were applied in drought condition in our study. stem fresh weight of wheat variety barigom 29 showed a great variation due to drought stress as indicated in table 2. the stem fresh weightplant-1 was 5.43 g in control condition and in drought condition it was 3.34g at 15 days after flowering. both zn and fe had positive impact under drought stress on stem fresh weight and the highest value of stem freshweightplant-1 (4.44 g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (4.14g), znso4.7h2o @ 5% solution as foliar spray (3.93g), znso4.7h2o @ 22 kgha-1(3.79g), fe3so4.7h2o @ 22 kgha-1(3.69g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (3.45g). thus, at 30 days after flowering, the stem fresh weight plant-1 was 10.38g in control condition and in drought condition it was 6.01g. application of zn and fe improved the ability of wheat plant to tolerate drought stress by maintaining greater stem fresh weight and the highest stem fresh weightplant-1 (7.03g) was recorded in fe3so4.7h2o @5% solution as foliar growth and yield of wheat as influenced by micronutrients 123 spray treatment followed by znso4.7h2o @ 22 kgha-1(6.90g), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (6.40g), fe3so4.7h2o @ 22 kgha-1(6.37g), znso4.7h2o @ 5% solution as foliar spray (6.27g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (6.21g). though drought stress adversely affected stem fresh weight in wheat, but the application of micronutrients established a positive effect with stem fresh weight in most of the cases. root fresh weight of the wheat variety bari gom 29 varied appreciably under drought stress as presented in table 2. application of zn and fe showed a better performance at 15 days after flowering in terms of root fresh weightplant-1 and in control condition it was recorded 1.18g, whereas in drought condition it was found 0.56gplant-1. after zn and fe application in drought condition, the highest root fresh weightplant-1 (0.81g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (0.74g), fe3so4.7h2o @ 22 kgha-1(0.68 g), znso4.7h2o @ 5% solution as foliar spray (0.68g), znso4.7h2o @ 22 kgha-1(0.62g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (0.61g). likewise, at 30 days after flowering, the positive influence of zn and fe on root fresh weight plant-1 was found and in control condition it was 1.83 g, whereas in drought condition it was 0.89g. the highest root fresh weightplant-1 (1.70g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o @ 5% solution as foliar spray(1.38g), fe3so4.7h2o @ 22 kgha-1 (1.32g), znso4.7h2o+ fe3so4.7h2o @ 22 kg ha-1 of both(1.31g), znso4.7h2o @ 22 kgha-1 (1.22g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (1.13g) under drought condition. it was reported by morizet et al. (1983) that root weight increased while shoot weight decreased with the application of water deficit stress. this result is in agreement with the findings reported by shahbaz et al. (2012) who showed a marked reduction of root fresh weight when wheat varieties were grown under drought stress for 7 weeks. table 2. effect of zn and fe micronutrients on leaf fresh weight, stem fresh weight, root fresh weight, and total fresh weight of wheat under drought stress at 15 and 30 days after flowering (daf) treat ments leaf fresh weight (gplant-1) stem fresh weight (gplant-1) root fresh weight (gplant-1) total fresh weight (gplant-1) 15 daf 30 daf 15 daf 30 daf 15 daf 30 daf 15 daf 30 daf c 3.57 3.98 5.43 10.38 1.18 1.83 10.18 16.19 d1 2.15 2.22 3.34 6.01 0.56 0.89 6.02 9.12 d2 2.42 2.57 3.79 6.90 0.62 1.22 6.83 10.69 d3 2.40 2.72 3.69 6.37 0.68 1.32 6.77 10.41 d4 2.57 2.64 4.14 6.40 0.74 1.31 7.45 10.25 d5 2.58 2.71 3.93 6.27 0.68 1.38 7.19 10.29 d6 3.30 3.40 4.44 7.03 0.81 1.70 8.55 12.13 d7 2.37 2.56 3.45 6.21 0.61 1.13 6.43 9.90 lsd(5%) 0.9 0.97 1.13 3.45 0.19 0.42 2.07 3.89 cv (%) 36 19.5 17.5 31.5 15.9 23.2 16.2 25.4 c= control, d1= drought, d2=drought+znso4.7h2o @ 22 kgha-1, d3= drought+fe3so4.7h2o @ 22 kgha-1, d4=drought+ znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both, d5=drought+ znso4.7h2o @ 5% solution as foliar spray, d6= drought+ fe3so4.7h2o @5% solution as foliar spray, d7= drought+ znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray. 124 tithi et al. total fresh weight of wheat variety bari gom 29 varied under drought stress as presented in table 2. at 15 days after flowering, in control condition the total fresh weightplant-1 was 10.18g and in drought condition it was 6.02g. application of zn and fereduced the adverse effect of drought stress and the highest total fresh weightplant-1 (8.55g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment, followed by znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (7.45g), znso4.7h2o @ 5% solution as foliar spray, (7.19g), znso4.7h2o @ 22 kgha-1 (6.83g), fe3so4.7h2o @ 22 kgha-1, (6.77 g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (6.43g). likewise, at 30 days after flowering, in control condition the total fresh weightplant-1 was 16.19g and in drought condition it was 9.12g and the highest total fresh weightplant-1 (12.13g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by fe3so4.7h2o @ 22 kgha-1 (10.69g), fe3so4.7h2o @ 22 kgha-1(10.41g), znso4.7h2o @ 5% solution as foliar spray (10.29 g), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (10.25g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (9.90g). it was noticed that drought stress badly reduced total fresh weight in wheat and the application of micronutrients showed the positive effects to mitigate the drought stress in wheat. zhang et al.(2011) reported that drought stress inhibited the growth of wheat seedlings, under drought stress, the root fresh weight was inhibited; reduction of water to promote root growth, and the root was relatively stout (ma et al., 2012). due to the lack of water, the aerial parts of slow growth, aboveground growth was inhibited, studies have shown that (yuehua, 2013; li and ma, 2013), drought stress suppressed the dry matter accumulation in wheat seedling, so for plant height, root length, fresh weight, dry weight, etc. the trend were decreasing, but the effect of the zn and fe were found better in this experiment. adequate zn nutrition improves vegetative growth and drought tolerance in alfalfa by enhancing root growth and rwc (grewal and williams, 2000). the maintenance of good leaf water status is a result of proper control exerted by the guard cells in diverse conditions, which improves the growth and enhances crop survival under stress conditions (steudle, 2002). yield attributes number of spikeplant-1 of wheat variety barigom 29 reduced significantly under drought stress as presented in table 3. the number of spikeplant-1 was 3.42in control condition and in drought condition it was 1.39. application of zn and fe had an influence to decrease the negative effect of drought stress and the highest number of spikeplant-1 (2.45) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment, followed by znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both(2.14), fe3so4.7h2o @ 22 kgha-1(2.04), znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (2.03), znso4.7h2o @ 5% solution as foliar spray (1.89) and the lowest was recorded in znso4.7h2o @ 22 kgha-1(1.76) under micronutrients treated condition. spike length of wheat variety bari gom 29 varied significantly under drought stress as presented in table 3. the spike length was 10.80 cm in control condition and in drought condition it was found9.01 cm. application of zn and fe tended to reduce the adverse effect of drought stress in most of the cases and the highest spike length (10.72cm) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o @ 5% solution as foliar spray (10.18 cm), fe3so4.7h2o @ 22 kgha-1(10.12cm), znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both (9.87cm), znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (9.82cm) and the lowest was recorded in znso4.7h2o @ 22 kgha1(9.75cm) under zn and fe applied condition. spike length has important contribution to the final crop yield, it effects on the number of spikeletspike-1, grain size and number of growth and yield of wheat as influenced by micronutrients 125 grainsspike-1. more spike length leads to more number of spikelet spike-1 which leads to more number of grains and then ultimately the maximum crop yield. sharafizad et al. (2013) reported that moderate dosage of salicylic acid (1.2 mm) increased spike length. table 3. effect of zn and fe micronutrients on yield and yield contributing characters of wheat under drought stress treatments number of spikeplant-1 spike length (cm) 100-grain weight (g) grain yieldplant-1 (g) straw yieldplant-1 (g) c 3.42 10.80 5.41 35.89 20.20 d1 1.39 9.01 4.16 10.85 6.70 d2 1.76 9.75 4.49 11.13 7.48 d3 2.04 10.12 4.84 14.97 8.28 d4 2.14 9.87 4.92 11.30 6.97 d5 1.89 10.18 4.68 15.06 8.48 d6 2.45 10.8 5.16 16.10 9.12 d7 2.03 9.82 4.35 11.29 7.57 lsd (5%) 0.96 0.72 0.59 5.91 3.02 cv (%) 26.9 4.2 7 21.8 18.8 c= control, d1= drought, d2=drought+znso4.7h2o @ 22 kg ha-1, d3= drought+fe3so4.7h2o @ 22 kgha1, d4=drought+ znso4.7h2o+ fe3so4.7h2o @ 22kgha-1 of both, d5=drought+ znso4.7h2o @ 5% solution as foliar spray, d6= drought+ fe3so4.7h2o @5% solution as foliar spray, d7= drought+ znso4.7h2o+ fe3so4.7h2o @ 5 % solution of both as foliar spray. individual grain weight is an important yield parameter that plays an important role in the actual yield of the crop. 100-grain weight of wheat variety bari gom 29 showed a variation due to drought stress as presented in table 3. in control condition the 100-grain weight was 5.41 g and in drought condition it was 4.16 g. under drought stress when zn and fe were applied, the highest 100grain weight (5.16g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o+ fe3so4.7h2o @ 22kgha-1of both (4.92g), fe3so4.7h2o @ 22 kgha-1 (4.84g), znso4.7h2o @ 5% solution as foliar spray (4.68g), znso4.7h2o @ 22 kgha-1(4.49g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (4.35g).monjezi et al. (2013) proposed that zinc spray alleviates drought stress effect on thousand grain weight in wheat. treated wheat plants with sa or zn resulted in significant increases in the number of tillers and spikesplant-1 as well as of grainsplant-1and weight of grains when irrigated water every 14 and 28 days reported by mahmoud (2015). grain yieldplant-1 of wheat variety bari gom 29 varied widely under drought stress as presented in table 3. in control condition the grain yieldplant-1was 35.89 g and in drought conditions it was 10.85g. and under drought condition the highest grain yieldplant-1 (16.10g) was recorded when fe3so4.7h2o @5% solution was applied as foliar spray followed by znso4.7h2o @ 5% solution as foliar spray (15.06 g), fe3so4.7h2o @ 22 kg ha-1 (14.97g), znso4.7h2o + fe3so4.7h2o @ 22 kg ha-1 of both(11.30g), znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (11.29g) and the lowest was recorded in znso4.7h2o @ 22 kgha-1 (11.13g). these findings are in agreement with the results of monjezi et al. (2013) who recorded the highest seed yield from the simultaneous application of iron and zinc, under the stress-free condition and application of iron under the stress-free condition were 660.79 and 651.67 gm-2, respectively. drought stress at any particular stage or during entire growing season considerably reduced the yield and components of yield in wheat crop (nasri, 2005). raza et al. (2012) found maximum reduction in grain yield plant-1 (48.45%)when drought 126 tithi et al. occurred at grain filling stage, whereas about 10.45% and 25.15%in grain yield plant-1 was noticed when drought occurred at tillering and anthesis stage of wheat, respectively. maleki et al. (2014) stated that, zinc sulfate can decrease negative effects of drought stress on maize grain yield and yield components straw yieldplant-1 of wheat variety barigom 29 varied appreciably under drought stress as presented in table 3. in control condition the straw yieldplant-1was 20.20 g and in drought condition it was 6.70 g. application of zn and fe tended to alleviate the detrimental effect of drought stress in most of the cases and the highest straw yieldplant-1(9.12 g) was recorded in fe3so4.7h2o @5% solution as foliar spray treatment followed by znso4.7h2o @ 5% solution as foliar spray (8.48g), fe3so4.7h2o @ 22 kgha-1(8.28g), znso4.7h2o+ fe3so4.7h2o @ 5% solution of both as foliar spray (7.57g) d2(7.48 g) and the lowest was recorded in znso4.7h2o+ fe3so4.7h2o @ 22kgha-1of both (6.97g). withholding water after anthesis reduced straw yield by 28.5% as claimed by johari-pireivatlou (2010). shirazi et al. (2014) found that different irrigation regimes had significant effect on the straw yield. straw yield exhibited the tendency of increasing with the increase of irrigation levels. this might be due to the luxuriant vegetative growth in terms of plant height and numbers of tillerplant-1. zn application results in appreciable increase in leaf area, the content of chlorophyll and other photosynthetic pigments, and stomatal conductance, thus resulting in improved growth and yield (karim et al., 2012). similarly, sultana et al. (2016) noted that zn countered the adverse impact of drought and remarkably increased wheat productivity. in another study, chattha et al. (2017) noted that zn application improved maize yield and harvest index in drought stress. moreover, hera et al. (2018) noted that foliar applied zn diminished the negative impacts of water deficit and increased growth and yield of wheat. seadh et al. (2009) reported that the mixture of four micronutrients (cu, mn, fe and zn) at the rate of 500 ppm produced the highest values of grain and straw yields with the micronutrient foliar application treatments in wheat. conclusion water deficit stress negatively affects the plant height, fresh weight of leaf, stem and root as well as yield of wheat. application of fe and zn micronutrients reduced the adverse effects of drought stress and improved these parameters of wheat under drought condition. among the micronutrients, fe (fe3so4.7h2o) was found more effective when it was applied as foliar spray @ 5% solution for increasing the growth and yield of wheat in water deficit condition. acknowledgement: the authors are grateful to ministry of science and technology, government of bangladesh for funding the research. references abbas, g., m.q. khan, m.j. khan, f. hussain and i. hussain. 2009. effect of iron on the growth and yield contributing parameters of wheat (triticum aestivum l.). the j. of animal & plant sci. 19(3): 135-139. arnon, i. 1972. crop production in dry regions. vol. i: background and principles, london: leonard hill (1972), p.650. barc (bangladesh agricultural research council). 2012. fertilizer recommendation guide. bangladesh agricultural research council. farmgate, dhaka. growth and yield of wheat as influenced by micronutrients 127 bayoumi, t.y., m.h. eid and e.m. metwali. 2008. application of physiological and biochemical indices as a screening technique for drought tolerance in wheat genotypes. afr. j. biotech. 7(14): 1684-5315. chattha, m.u., m.u. hassan, i. khan, m.b. chattha, a.mahmood, m.u. chattha, m. nawaz, m.n. subhani, m. kharal and s. khan. 2017. biofortification of wheat cultivars to combat zinc deficiency. front. plant sci.8: 281.[crossref] [pubmed. gomez, a.a. and a.a. gomez. 1984. statistical procedure of agricultural research. john wiley and sons. new york. 20-2015. grewal, h.s. and r. williams. 2000. zinc nutrition affects alfalfa responses to water stress and excessive moisture. j. plant nutri.23: 949–962. [crossref]. hera, m.h.r.., m. hossain and a.k. paul. 2018. effect of foliar zinc spray on growth and yield of heat tolerant wheat under water stress. int. j. biol. environ. eng.1: 10–16. johari-pireivatlou, m. 2010. effect of soil water stress on yield and proline content of four wheat lines. afr. j. biotech. 9(1): 1684-5315. kamal, a.h.m., k.h. kim, k.h. shin, j.s. choi, b.k. baik, h. tsujimoto and s.h. woo. 2010. abiotic stress responsive proteins of wheat grain determined using proteomics technique. aus. j. crop sci. 4(3): 196203. karim, m., y.q. zhang, r.r. zhao, x.p. chen, f.s. zhang and c.q. zou. 2012. alleviation of drought stress in winter wheat by late foliar application of zinc, boron, and manganese. j. plant nutr. soil sci.175: 142–151.[crossref]. li, m. and j.l. ma. 2013. influences of salt and drought stress on proline content in three popular varieties. hunan agric. sci. 1(110): 105-107. ma, f., d.d. li, j. cai, d. jiang, w.x. cao and t.b. dai. 2012. responses of wheat seedlings root growth and leaf photosynthesis to drought stress. chinese j. appl. ecol. 23(3): 724-730. mahmoud, r.s. 2015. application of salicylic acid and zinc improves wheat yield through physiological processes under different levels of irrigation intervals. int. j. plant res. 5(5): 136-156. maleki, a., s. fazel, r. naseri, k. rezaei and m. heydari. 2014. the effect of potassium and zinc sulfate application on grain yield of maize under drought stress conditions. adv. environ. biol. 890-894. manivannan, p., c.a. jaleel, b. sankar, a. kishorekumar, r. somasundaram, g.a. lakshmanan and r. panneerselvam. 2007. growth, biochemical modifications and proline metabolism in helianthus annuus l. as induced by drought stress. colloids and surfaces b: biointerfaces: 59(2): 141-149. monjezi, f., f. vazin and m. hassanzadehdelouei. 2013. effects of iron and zinc spray on yield and yield components of wheat (triticum aestivum l.) in drought stress. cercetari agronomice in moldova. 46(1): 23-32. morizet t., m. pollucsck and d. togola. 1983. drought tolerance in four maize varieties. int. j. bot. studies. 4(6): 43-50. nasri, m. 2005. interaction of nutrient elements and drought stress in cultivars of brassica napus. in the second international conference on integrated approaches to sustain and improve plant production under drought stress. rome, italy, september. 109: 24-28. nazar, r., n. iqbal, a. masood, m.i.r. khan, s. syeed and n.a. khan. 2012. cadmium toxicity in plants and role of mineral nutrients in its alleviation. american j. plant sci. 3(10): 241-624. raza, s., m.f., saleem, i.h., khan, m.jamil, m., ijaz and m.a. khan. 2012. evaluating the drought stress tolerance efficiency of wheat (triticum aestivum l.) cultivars. russian j. agric. socioeconomic sci. 12(12): 41-47. 128 tithi et al. salsinha, y.c.f., d. indradewa, y. asih purwestri and d. rachmawati. 2019. morphophysiologica lchanges during vegetative stage drought stress in the local pigmented rice (oryza sativa l.) from east nusatenggar. the 6th international conference on biological science icbs, aip conf. proc. 2260, 030020-1–030020-9; https://doi.org/10.1063/5.0015865published by aip publishing. 978-0-7354-2020-5/$30.00. saxena, i. and g.s. shekhawat.2013. nitric oxide (no) in alleviation of heavy metal induced phytotoxicity and its role in protein nitration. nitric oxide. 32: 13–20. seadh, s.e., m.i. el-abady, a.m. el-ghamryand s. farouk. 2009. influence of micronutrients foliar application and nitrogen fertilization on wheat yield and quality of grain and seed. j.biol. sci.9(8): 851-858. shahbaz, m., y. masood, s. perveen and m. ashraf. 2012. is foliar-applied glycinebetaine effective in mitigating the adverse effects of drought stress on wheat (triticum aestivum l.).j. appl. bot. food quality. 84(2): 192. sharafizad, m., a. naderi, s.a.siadat, t. sakinejad and s. lak. 2013. effect of drought stress and salicylic acid treatment on grain yield, process of grain growth, and some of chemical and morphological traits of chamran cultivar wheat (triticumaestivum). adv. environ. biol. 7(11): 3234-3241. shirazi m.u, m.a. khan, n. bhatti, a. unar, a.h.b. bozdar, s.m. mujtaba and m.i. lashari. 2014. growth and water use efficiency in wheat genotypes grown under water stress condition. j. agric. res. develop. 4: 023-028. steudle, e. 2002. water uptake by roots: effects of water deficit.j. exp. bot.51: 1531–1542. [crossref][pubmed]. sultana, s., h.m. naser, n.c. shil, s.akhter and r.a. begum. 2016. effect of foliar application of zinc on yield of wheat grown by avoiding irrigation at different growth stages. bangladesh j. agric. res.41: 323–334.[crossref]. tabatabai, s.m.r., m. oveysi and r. honarnejad. 2015. evaluation of some characteristics of corn under water stress and zinc foliar application. adv. environ. biol. 16: 34-38. tripathi, d.k., g. bashri, s. shweta, p. ahmad and v. singh. 2017. efficacy of silicon against aluminum toxicity in plants: an overview. silicon in plants: adv. future prospects. 1: 355366. wang, w. x., t. barak, b. vinocur, o. shoseyov and a. altman. 2003. abiotic resistance and chaperones: possible physiological role of sp1, a stable and stabilizing protein from populus. in: plant biotech. 2002 and beyond. 439-443. yuehua, s.m. 2013. effect of drought stress simulated by peg-6000 on physiological character of syneilesis aconitifolia. zhang, y.q., q. lin, j.b. liu, h.s. zhang and c.x. zhao. 2011. effects of drought stress on photosynthetic characteristics and yield of different fertilizer and water types of wheat. j. tritic. crops. 31(4): 724-730. https://doi.org/10.1063/5.0015865 bangladesh agron. j. 2022, 25(2): 57-65 effect of added urea foliar spray and leaf clipping on growth and yield response of mungbean m.d. hossain1, m.f. karim2, p.k. biswas2 and m.h. mahmud3 1farm superintendent, bangladesh wheat and maize research institute, regional station, jamalpur 2department of agronomy, sau dhaka-1207, bangladesh 3project implementation unit-barc, national agricultural technology program-phase-ii project, barc, dhaka-1215, corresponding e-mail: dalour94@gmail.com (received: 07 october 2022, accepted: 20 january 2023) keywords: leaf clipping, foliar spray, growth, yield, mungbean abstract an experiment was conducted at sher-e-bangla agricultural university, dhaka, during march to may 2018 to study the impact of added urea foliar spray and leaf clipping on growth and yield of mungbean. the experiment was laid out in splitplot design with three replications and composed of four levels of urea foliar spray viz. f0 = recommended fertilizer (rf) + no foliar spray (fs), f1 = rf + 1% urea fs at flower initiation (fi), f2 = rf + 2% urea fs at fi, f3 = rf + 3% urea fs at fi and four levels of leaf clipping viz. c0 = no leaf clipping, c1 = clipping 1 basal leaf, c 2 = clipping 2 basal leaves, c3= clipping total apical leaves having no inflorescence. results indicated that foliar spray and leaf clipping had significant effect on most of the growth and yield contributing parameters. in case of foliar spray of urea, the maximum plant height, nodules plant-1, highest above ground dry matter plant-1, pods plant-1, pod length, seeds pod-1, 1000 seed weight, seed yield, stover yield and biological yield were recorded from f0. in case of leaf clipping, all growth and yield attributes were recorded highest from c1. regarding combined effect, the highest growth and yield parameters were recorded from the treatment combination of f0c1. so, f0 along with c1 is suggested for yield improvement in mungbean cultivation. introduction pulses are the cheapest source of high quality proteins, minerals and energy in human diet. with the development of irrigation facilities, the area of cultivation of hyv cereal crops has been increased significantly, while pulses have been pushed to marginal lands of low yield potential. the area under pulse production has been decreasing continuously in bangladesh alarmingly (shahjahan, 2001). in bangladesh, a large number of people are suffering from malnutrition. pulses are cheaper sources of protein than animal proteins (singh and jambunathan, 1989). a minimum per capita intake of pulse should be 80 g day-1, whereas it is 8.72 g day-1 in bangladesh. the total production of mungbean in bangladesh during 2016-17 was 34,783 tons from an area of 1, 02,311 ha (bbs, 2018). fertilizers (n and p) may increase significantly mungbean yield (patel and parmer, 1986) by increasing root growth, nodulation, leaf area, and total dry matter. foliar applied n to mungbean at flowering stage was found to increase seed yields (abdo, 2001). the foliar application of nitrogen alone was more effective than npk combinedly in producing higher number of seeds per pod (hamayun et al., 2011). in this situation foliar spray of urea at 58 hossain et al. flowering could be an option to check the abortion rate in pulses. but optimum fertilizer requirement depends on soil fertility levels and methods of application. in this context the foliar application of nitrogen at flowering stage may fulfill the nitrogen requirement of plant at its flowering stage received very minimum n (20 kg ha-1) as basal dose. sink in mungbean is determined by the number of pods per plant (mackenzie et al., 1975), number of seeds per pod and weight of' an individual seed (avrdc, 1976). removal of apical shoot above node 5 or removal of inflorescence or axillary bud at nodes 1-4 together with the apical shoot greatly increased pod number and seed weight of mungbean (clifford, 1979). thus, the study was undertaken to maximize the seed yield of mungbean by manipulating its sourcesink through removal of selective leaves and additional foliar spray of urea during onset of flowers. materials and methods the present research work was conducted at sher-ebangla agricultural university farm, dhaka-1207 during the period from march to may, 2018 which belongs to 2377n latitude and 9033e longitude and the agro-ecological zone of the modhupur tract, aez-28 (anonymous, 1988). the experiment was carried out in split-plot design with three replications. foliar spray treatments were assigned in the main plots and leaf clipping treatments were in the sub-plots. the experiment consists 4 levels of foliar spray of urea viz. i) f0: recommended fertilizer (rf) + no foliar spray (fs), ii) f1: rf + 1% urea fs at flower initiation (fi), iii) f2: rf + 2% urea fs at fi and iv) f3: rf + 3% urea fs at fi and 4 levels of leaf clipping viz. i) c0: no leaf clipping, ii) c1: clipping 1 basal leaf, iii) c 2: clipping 2 basal leaves and iv) c3: clipping total apical leaves having no inflorescence. the seed of the test crop i.e., bari mung-5 was collected from bangladesh agricultural research institute (bari), joydebpur, gazipur. seeds were sown in line in main plot after good tilth of land. the experimental area was fertilized with 20, 40, 20, 20 and 01 kg ha-1 of n, p2o5, k2o, s and b. the entire amount of tsp, mop, gypsum and boric acid were applied during the final preparation of land. in addition that 0, 1, 2 and 3 % urea solution were prepared with water. those solutions were applied in the field using a knapsack sprayer on the mungbean leaves thoroughly during flower initiation. after establishment of seedlings, various intercultural operations were accomplished for better growth and development of the mungbean. the height of plant was recorded in centimeter (cm) at harvest. data were recorded from randomly selected 5 plants each plants and then average the parameters viz, plant height from the ground level to the tip of the plant, above ground dry matter and number of pods plant-1. the number of nodules plant-1 was observed and counted from each plot and average number of nodules plant-1 at 60 das was recorded. pod length and the number of seeds pods-1 was taken from randomly selected 20 pods of each treatment combination at the time of harvest. one thousand cleaned, dried seeds were counted randomly from each harvest sample and expressed in gram. the seeds and the stover collected from 1 square meter of each plot were sun dried properly. the weight of seeds was taken and converted the yield in t ha-1. biological yield was calculated by biological yield = seed yield + stover yield. harvest index was calculated from the ratio of grain yield to biological yield and expressed in percentage. the collected data were compiled and analyzed statistically using the analysis of variance (anova) technique using mstat-c computer package and the mean differences were adjusted by least significance difference (lsd) test at 5% level of probability. effect of foliar spray and leaf clipping on growth and yield of mungbean 59 results and discussion plant height plant height of mungbean at harvest showed statistically significant in combine effect of foliar spray and leaf clipping treatment, but insignificant in fertilizer management in respect of foliar spray of urea and leaf clipping treatment (table 1). the maximum plant height at harvest was 51.96 cm respectively, which were recorded from f0 which was statistically similar with f1 and f2. the minimum plant height 49.23 cm, at harvest was observed from f2. these are an agreement with those of palta et al. (2005) and zeidan (2003). in leaf clipping, the maximum plant height was recorded in c1 (51.46 cm) which was closely followed by c0 and c2 at harvest. on the other hand, the minimum plant height was obtained in c3 (48.74 cm). the finding is close conformity of findings with tripathi et al. (2012), kumar et al. (2009) and raj and tripathi (2005). the maximum plant height (61.20 cm) was obtained in the treatment combination of f0c1 which was statistically similar with f1c0 while the minimum plant height (45.10 cm) was recorded in the treatment combination of f1c1 which was statistically similar with f0c0, f0c3, f1c3, f2c0, f2c1, f2c3, f3c0, f3c1 and f3c2. above ground dry matter plant-1 statistically significant variation was found due to different foliar spray of urea, leaf clipping and treatment combination of above ground dry matter plant-1 at harvest (table 1). in case of foliar spray, the highest above ground dry matter plant-1 (11.89 g) was found from f0 which was statistically similar to f1, whereas the lowest dry matter plant-1 (10.57 g) was recorded in f3 which was statistically similar to f2. similar result was found by salisbury and ross (1985). in case of leaf clipping, the highest above ground dry matter plant-1 was recorded in c1 (11.85 g) which was closely followed by c2 and c0. on the other hand, the lowest dry matter plant-1 was obtained in c3 (10.27 g). the high source-sink ratio caused by defoliation increased the photosynthetic rates in the remaining leaves in okra, mungbean, soybean and groundnut (bhatt and rao, 2003; pandey and singh, 1984; chen and lia, 1991; ghosh and sengupta, 1986). the highest above ground dry matter plant-1 (14.76 g) was obtained in the treatment combination of f0c1 which was statistically similar with f3c3 while the lowest dry matter plant-1 (8.41 g) was recorded in the treatment combination of f0c0 which was statistically similar with f0c2, f0c3, f2c0, f2c3 and f3c1. number of nodules plant-1 statistically significant variation was found due to different foliar spray of urea, leaf clipping and its combination in terms of nodules plant-1 at 60 das (table 1). the highest nodules plant-1 (3.00) was found from f0 which was statistically similar to f3 and followed by f1, whereas the lowest nodules plant-1 (2.38) was recorded in f2 from foliar spray treatment. tripathi et al. (2012) and muhammad et al. (2006) found that production of nodules plant-1 differed significantly due to different fertilizer application in many legumes. in case of leaf clipping, the highest nodules plant-1 (3.01) was found in c1 which was statistically similar to c0, while the lowest nodules plant-1 was recorded in c3 (2.53) which was statistically similar to c2. the highest nodules plant-1 (3.40) was found in the treatment combination of f0c1 which was statistically similar to f0c0, f0c3, f1c2, f1c3, f3c0, f3c1 and f3c3. the lowest nodules plant-1 (1.87) was observed in the treatment combination of f2c0 which was statistically similar to f0c2, f1c0, f2c0, f2c1 and f3c 2. pod length statistically non-significant variation was recorded for pod length due to fertilizer management in respect of foliar spray of urea, leaf clipping and combination treatment (table 1). the highest pod length (7.70 cm) was recorded from f0 followed by f1 where the lowest pod length (7.33 60 hossain et al. cm) was observed from f3 which was statistically identical with f2. azadi et al., (2013) showed that stem diameter, number of node and seed yield showed significant difference among various amounts of nitrogen fertilizer where pod length varied non-significantly. numerically highest pod length (7.57 cm) was observed from c1 which was similar to c2 and c0 and the lowest pod length (7.41 cm) was observed from c3. from combination treatment, the numerically longest pod length (7.82 cm) was recorded from the treatment combination of f0c1. numerically the shortest pod length (7.14 cm) was found from f3c0. number of pods plant-1 statistically significant variation was recorded for number of pods plant-1 due to fertilizer management in respect of foliar spray of urea and combination treatment but insignificant in leaf clipping treatment (table 1). in case of foliar spray, the highest number of pods plant-1 (7.96) was recorded from f0 followed by f1 where the lowest number of pods plant-1 (6.51) was observed from f3 which was statistically similar to f2. patel and patel (1994) reported the similar results. in case of leaf clipping, numerically highest number of pods plant-1 (7.49) was observed from c1 which was statistically similar to c2 and c0 and the lowest number of pods plant-1 (6.87) was observed from c3. these results are in conformity with bernacchi et al. (2007) who observed that transpiration was proportional to leaf conductance in soybean under constant environmental conditions. the highest number of pods plant-1 (9.81) was recorded from the treatment combination of f0c1 which was statistically similar to f0c3, f3c0, and f3c3. the lowest number of pods plant-1 (5.66) was found from f1c3 which was statistically similar to f0c0, f0c2, f1c1, f1c3, f2c0, f2c1, f2c2, f2c3, f3c1, and f3c2. patel and patel (1994) found similar results. table 1. interaction effect of foliar spray and leaf clipping on plant height, above ground dry matter plant-1, nodules plant-1, pod length and pods plant-1 of mungbean treatments plant height (cm) above ground dry matter plant-1 (g) nodules plant1 (no.) pod length (cm) pods plant-1 (no.) foliar spray f0 51.96 11.89 3.00 7.70 7.96 f1 49.99 11.40 2.67 7.62 7.70 f2 49.23 10.77 2.38 7.42 7.14 f3 49.49 10.57 2.88 7.33 6.51 lsd(0.05) ns 0.42 0.88 ns 0.08 leaf clipping c0 50.61 11.17 2.82 7.54 7.46 c1 51.46 11.85 3.01 7.57 7.49 c2 49.86 11.35 2.55 7.55 7.55 c3 48.74 10.27 2.53 7.41 6.87 lsd(0.05) ns ns ns ns ns interactions f0c0 48.71 8.41 2.80 7.59 5.81 f0c1 61.20 14.76 3.40 7.82 9.81 f0c2 51.03 9.71 2.40 7.61 6.04 f0c3 46.89 10.19 3.40 7.78 9.14 f1c0 55.82 10.91 2.27 7.72 8.19 f1c1 45.10 10.50 2.60 7.23 6.80 f1c2 50.77 12.41 3.00 7.35 7.91 f1c3 46.27 11.78 2.80 7.36 5.66 f2c0 50.63 10.04 1.87 7.21 6.49 f2c1 50.33 11.09 2.40 7.77 6.85 f2c2 51.47 12.62 2.67 7.76 6.90 f2c3 47.53 8.53 2.53 7.75 5.80 effect of foliar spray and leaf clipping on growth and yield of mungbean 61 f3c0 50.69 11.71 3.27 7.14 9.49 f3c1 45.81 9.03 2.87 7.32 6.36 f3c2 46.16 12.65 2.07 7.55 6.61 f3c3 54.27 14.18 3.3 7.32 9.36 lsd(0.05) 5.602 1.98 0.60 ns 1.37 cv (%) 6.63 10.52 13.10 9.58 11.07 f0 = recommended fertilizer + no foliar spray, f1 = recommended fertilizer + 1% urea foliar spray at flower initiation, f2 = recommended fertilizer + 2% urea foliar spray at flower initiation, f3 = recommended fertilizer + 3% urea foliar spray at flower initiation. c0 = no leaf clipping, c1 = clipping 1 basal leaf, c2 = clipping 2 basal leaves, c3 = clipping total apical leaves having no inflorescence number of seeds pod-1 statistically significant variation was recorded for number of seeds pod-1 due to fertilizer management in respect of foliar spray of urea and interaction effect of foliar spray and leaf clipping but insignificant leaf clipping treatment (table 2). in case of foliar spray, the highest number of seeds pod-1 (10.92) was recorded from f0 followed by f1 where the lowest number seeds pod-1 (9.92) was observed from f3 which was statistically similar to f2. this result was close to mahajan et al. (2016). in case of leaf clipping, numerically highest number seeds pod-1 (10.54) was observed from c1 which was statistically similar to c0 and c2. the lowest number of seeds pod-1 (10.17) was observed from c3. this observation agreed with those of pandey (1983) who worked in cowpea and hintz and fehr (1990) who worked in soybean. the highest number of seeds pod-1 (12.08) was found from the treatment combination of f0c1 which was statistically similar to f1c2, f2c0, f2c1, f2c2, f2c3, f3c0, and f3c3. the lowest number of seeds pod-1 (9.20) was found from f0c3 which was statistically similar to f0c0, f0c2, f1c0, f1c1, f1c2, f1c3, f2c1, f2c3, f3c0, f3c1, f3c2, and f3c3. combined foliar spray and leaf clipping may support the plant to stop floral dropping, hence empty or partially filled pod production reduced. thousand seeds weight statistically non-significant variation was recorded for thousand seeds weight in all cases of treatments (table 2). in case of foliar spray, the highest thousand seeds weight (46.33 g) was recorded from f0 followed by f1, where the lowest thousand seeds weight (45.60 g) was observed from f3 which was statistically identical with f2. rajender et al. (2002) showed 1000seed weight increased with increasing n rates. the highest thousand seeds weight (46.49 g) was observed from c1 which was statistically similar to c2 and c0 and the lowest thousand seed weight (44.54 g) was observed from c3. similarly clifford (1979) found increased grain weight after the removal of axillary buds. the highest thousand seeds weight (48.07 g) was recorded from the treatment combination of f0c1. the lowest thousand seeds weight (43.32 g) was found from f1c0. seed yield statistically non-significant variation was recorded for seed yield due to fertilizer management in respect of foliar spray of urea but significant in leaf clipping and combination effect (table 2). in case of foliar spray, numerically the highest seed yield (0.90 t ha-1) was recorded from f0 followed by f1 where the lowest seed yield (0.83 t ha-1) was observed from f2 and f3. similar observations were reported by rahman et al. (2014) who observed that foliar spray of n, p and k significantly increased pods/plant, seeds / pod, biomass and grain yield in common bean. significantly highest seed yield (0.98 t ha-1) was observed from c1 which was statistically similar to c0 and c2 and the lowest seed yield (0.8 t ha-1) was observed from c3. clifford (1979) reported an increased seed weight by removing axillary buds in mungbean. the highest seed yield (1.26 t ha-1) was recorded from the treatment combination of f0c1 which was statistically 62 hossain et al. similar to f3c3. the lowest seed yield (0.60 t ha-1) was found from f0c0 which was statistically similar to f0c2, f0c3, f1c1, f1c3, f2c0, and f3c2. stover yield statistically significant variation was recorded for stover yield due to fertilizer management in respect of foliar spray of urea, leaf clipping and combination of treatment (table 2). the significantly highest stover yield (2.49 t ha-1) was recorded from f1 followed by f0 where the lowest stover yield (2.11 t ha-1) was observed from f3 which was statistically identical to f2. mahajan et al. (1994) found that soil application of 1% urea foliar spray at flower initiation increased stover yield significantly of groundnut. the highest stover yield (2.42 t ha-1) was observed from c1 which was statistically similar to c2 and c0 and the lowest stover yield (2.20 t ha-1) was observed from c3. higher rate of photosynthesis in remaining leaves of partially clipped plants compared to the leaves in intact plants may contribute the compensation to source loss by clipping in soybean (rao and ghildiyal, 1985). the highest stover yield (2.62 t ha1) was recorded from the treatment combination of f0c1 which was statistically similar to f0c2, f0c3, f1c0, f1c1, f1c2, f1c3, f2c1, f2c2 and f3c3. the lowest stover yield (1.76 t ha-1) was found from f2c3 which was statistically similar to f0c0, f3c0, f3c1 and f3c2. biological yield statistically significant variation was recorded for stover yield due to fertilizer management in respect of foliar spray of urea, leaf clipping and its treatment combination (table 2). the highest biological yield (3.32 t ha-1) was recorded from f0 followed by f1 where the lowest biological yield (3.07 t ha-1) was observed from f2 which was statistically identical to f3. the highest biological yield (3.40 t ha-1) was observed from c1. the lowest biological yield (3.00 t ha-1) was observed from c3, which was statistically similar to c2 and c0. the high source sink ratio caused by defoliation increased the photosynthetic rates in the remaining leaves in okra, mungbean, soybean and groundnut (bhatt and rao, 2003; pandey and singh, 1984; chen and lia, 1991; ghosh and sengupta, 1986). the highest biological yield (3.88 t ha-1) was recorded from the treatment combination of f0c1 which was statistically similar to f1c0, f2c1 and f3c3. the lowest biological yield (2.53 t ha-1) was found from f3c2 which was statistically similar to f0c0, f2c0, f2c3, f3c0, f3c1 and f3c2. table 2. effect of foliar spray and leaf clipping on seeds pod-1, weight of 1000 seeds, seed yield, straw yield, biological yield and harvest index of mungbean treatments seeds pod-1 (no.) weight of 1000 seeds (g) seed yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) foliar spray f0 10.92 46.33 0.90 2.45 3.32 25.79 f1 10.34 46.18 0.88 2.49 3.18 24.90 f2 10.22 45.77 0.83 2.18 3.01 28.73 f3 9.92 45.60 0.83 2.11 3.00 29.70 lsd(0.05) 0.88 ns ns 0.09 0.11 2.73 cv (%) 11.32 9.88 11.74 8.99 11.56 12.03 leaf clipping c0 10.40 45.82 0.84 2.23 3.07 26.52 c1 10.54 46.49 0.98 2.42 3.41 26.58 c2 10.28 46.02 0.82 2.27 3.09 28.64 c3 10.17 44.54 0.80 2.20 3.00 27.42 lsd(0.05) ns ns 0.08 0.22 0.26 ns effect of foliar spray and leaf clipping on growth and yield of mungbean 63 interactions f0c0 10.05 47.35 0.60 1.94 2.53 23.66 f0c1 12.08 48.07 1.26 2.62 3.88 32.55 f0c2 10.02 43.36 0.74 2.47 3.21 22.99 f0c3 9.20 46.54 0.74 2.35 3.09 23.97 f1c0 10.08 43.32 0.96 2.61 3.58 26.86 f1c1 10.30 45.31 0.76 2.57 3.32 22.77 f1c2 10.60 44.73 0.88 2.43 3.31 26.56 f1c3 9.88 45.04 0.71 2.33 3.05 23.39 f2c0 11.12 45.48 0.71 2.19 2.90 24.43 f2c1 10.50 45.74 1.08 2.42 3.50 30.96 f2c2 11.22 44.95 0.97 2.37 3.34 29.19 f2c3 10.84 46.92 0.77 1.76 2.53 30.33 f3c0 10.37 47.14 0.93 2.07 3.01 31.14 f3c1 9.27 44.97 0.82 2.09 2.91 28.30 f3c2 9.28 45.13 0.68 1.80 2.49 27.34 f3c3 10.75 47.46 1.16 2.47 3.62 32.01 lsd(0.05) 1.73 ns 0.17 0.43 0.52 4.27 cv (%) 9.94 9.25 11.58 11.23 9.93 9.28 f0 = recommended fertilizer + no foliar spray, f1 = recommended fertilizer + 1% urea foliar spray at flower initiation, f2 = recommended fertilizer + 2% urea foliar spray at flower initiation, f3 = recommended fertilizer + 3% urea foliar spray at flower initiation. c0 = no leaf clipping, c1 = clipping 1 basal leaf, c2 = clipping 2 basal leaves, c3 = clipping total apical leaves having no inflorescence harvest index statistically significant variation was recorded for harvest index due to fertilizer management in respect of foliar spray of urea and treatment combination, but insignificant in leaf clipping of mungbean (table 2). the highest harvest index (29.7%) was recorded from f3 followed by f2 where the lowest harvest index (24.9%) was observed from f1 which was statistically similar to f0. the highest harvest index (28.64%) was observed from c2, which was statistically similar to c3. the lowest harvest index (26.52%) was observed from c0, which was statistically similar to c2. from combination treatment, the highest harvest index (32.55%) was recorded from the treatment combination of f0c1 which was statistically similar to f2c1, f2c2, f2c3, f3c0, f3c1 and f3c3. the lowest harvest index (22.77%) was found from f1c1 which was statistically similar to f0c0, f0c2, f0c3, f1c0, f1c2, f1c3 and f2c0. hamid (1994) demonstrated that the development of tertiary branches and much of the secondary branches in mungbean is counterproductive. conclusion considering the above results, it may be concluded that fertilizer dose and leaf clipping had significant role in the grain yield. among the fertilizer dose and leaf clipping, recommended fertilizer dose with no foliar spray and clipping 1 basal leaf gave best yield. so, recommended fertilizer dose with clipping 1 basal leaf is very important to get optimum yield of mungbean variety. however, further experimentation will need to be executed in different agro-ecological zones with more varieties under recommended fertilizer dose with clipping basal leaf to reach a specific conclusion and recommendation. 64 hossain et al. acknowledgement the author acknowledged the ministry of science and technology, govt. of the peoples republic of bangladesh for providing financial support to conduct the study at sher-e-bangla agricultural university. references abdo, f.a. 2001. the response of two mungbean cultivars to zinc, manganese and boron. morphological, physiological and anatomical aspects. bulletin of faculty of agriculture, cairo university. 52(3): 445-466. anonymous. 1988. the year book of production. fao, rome, italy. avrdc. 1976. asian vegetable research and development center. mungbean annual report for 1975. shanhua, tanian, taiwan. azadi, e., m. rafiee and h. nasrollahi. 2013. the effect of different nitrogen levels on seed yield and morphological characteristic of mungbean in the climate condition of khorramabad. ann. biol. res. 4 (2): 51-55. bernacchi, c.j., b.a. kimball, d.r. quarles, s.p. long and d.r. ort. 2007. decreases in stomatal conductance of soybean under open-air elevation of co2 are closely coupled with decreases in ecosystem evapotranspiration. plant physiol. 143: 134-144. bbs. 2018. bangladesh bureau of statistics. statistics division. yearbook of statistics of bangladesh. ministry of planning, government of the peoples republic of bangladesh, dhaka. bhatt, r.m. and n.k.s. rao. 2003. influence of leaf excision on photosynthesis, seed setting and yield in okra. indian j. plant physiol. 8: 345-348. chen, c.y. and w.s.i. lia. 1991. effects of source-sink alteration on stomatal movement in different soybean cultivars. photosynthetica. 25: 437-439. clifford, p.e. 1979. source limitation of sink yield in mungbean. ann. bot. 43: 397-399. ghosh, b.k. and u.k. sengupta. 1986. effect of source manipulation on photosynthetic activity in groundnut. indian j. plant physiol. 29: 351-356. hamayun, m., s.a. khan and a.l. khan. 2011. effect of foliar and soil application of nitrogen, phosphorus and potassium on yield components of lentil. pakistan. j. bot. 43(1): 391-396. hamid m.a. 1994. growth and reproduction of mungbean in a wide range of population densities. munghean session. international symposium on pulses research. new delhi, 1994. hintz, w.r. and w.r. fehr. 1990. plant density and defoliation effect on the recovery of soybean injured by stem cut off during vegetative development. agron. j. 82: 57-59. kumar, m., o.p. lathwal and s. kumar. 2009. growth behaviour of mungbean genotypes under varying sowing time during summer season. haryana j. agron. 25(1&2): 79-81. mackenzie, d.r., n.c. chen, t.d. liou, b.f. henry and e.b. oyer. 1975. response of mungbean (vigna radiata l.) and soybean (glycine max l.) to increasing plant density. american soc. hort. 100(5): 579-583. mahajan, h.s., y.g. patil, n.a. hirwe, t.r. patil and m.r. deshmukh. 2016. effect of foliar nutrition of urea and diammonium phosphate on seed yield and economics of sesame (sesamum indicum l.) under rainfed situation. intl. j. agric. sci. 12(1): 101-105. mahajan, t.s., a.s. chavan and j.h. dongale. 1994. effect of boron on yield and quality of groundnut on laterite soil. indian j. agric. sci. 64(8): 532-535. effect of foliar spray and leaf clipping on growth and yield of mungbean 65 muhammad, a., r. abdul, a. muhammad and m.i. zafar. 2006. association among rhizobium phaseoli strains and mungbean genotypes under rainfed conditions. sarhad j. agric. 22(3): 453-457. palta, j.a., a.s. nandwal, s. kumari and n.c. turner. 2005. foliar nitrogen applications increase the seed yield and protein content in chickpea (cicer arietinum l.) subject to terminal drought. australian j. agric. res., 56: 105-112. pandey, r.k. and v.b. singh. 1984. influence of source and sink size on growth and seed yield of mungbean (vigna radiata). legume res. 7: 27-36. pandey, r.k. 1983. influence of defoliation on seed yield in cowpea (vigna unguiculata l. waip.) in a sub-tropical environment, field crop res. 7: 249-265. patel, j.r. and z.g. patel. 1994. effect of foliar fertilization of nitrogen and phosphorus on growth and yield of summer mungbean (vigna radiata l.). indian j. agron. 39(4): 574-580. patel, d.b. and r.k. parmer. 1986. physiological analysis of yield variation in mungbean (vigna radiata l.). j. agron crop sci. 165: 120-132. rahman, r. and k. venkataramana. 2006. effect of foliar nutrition on npk uptake, yield attributes and yield of greengram (vigna radiata l.). crop res. hisar. 32(1): 21-23. rahman, i.u., a. afzal, a. asghar, z. iqbal, f. ijaz, s. manan, k. khan, s. karim and g. qadir. 2014. growth and yield of phaseolus vulgaris as influenced by different nutrient treatments. intl. j. agron. agri. res. 4(3): 20-26. raj, s. and k.p. tripathi. 2005. productivity and economics of mungbean (vigna radiata l.) as influenced by varieties and nutrient management. j. arid leg. 2(2): 223-226. rajender, k., v.p. singh and r.c. singh. 2002. effect of n and p fertilization on summer planted mungbean (vigna radiata l.). crop res. hisar. 24(3): 467-470. salisbury, f.b. and c.w. ross. 1985. plant physiology. 3rd ed. wadsworth, belmont, ca. p. 540. shahjahan, m. 2001. pulses in bangladesh: production, problems, prospect and future plans. research report on post harvest technology of crops 2000-2001. bangladesh agricultural research institute, joydebpur, gazipur. singh, u. and r. jambunathan. 1989. pulses as a substitute for animal protein. the proceedings of advances in pulses research in bangladesh, national workshop on pulses, june 6–8. (pp. 191-97). bari, joydebpur, bangladesh. tripathi, p.k., m.k. singh, j.p. singh and o.n. singh. 2012. effect of rhizobial strains and sulphur nutrition on mungbean (vigna radiata l.) cultivars under dryland agro-ecosystem of indogangetic plain. african j. agril. res. 7(1): 34-42. zeidan, m.s. 2003. effect of sowing dates and urea foliar application on growth and seed yield of determinate faba bean (vicia faba l.) under egyptian conditions. egypt j. agron., 24: 93102. microsoft word 6. baj-473e bangladesh agron. j. 2024, 26(2): 41-48 determination of optimum nitrogen level for maximizing yield of two hyv boro rice varieties in bogura region, bangladesh s.m.m.s. tonmoy1*, t.k. roy2, a. sannal3, m.a.u. razu4 and m.m. rana5 1farm management division, bangladesh rice research institute, gazipur-1701, bangladesh 2 entomology division, bangladesh rice research institute, gazipur-1701, bangladesh 3 plant pathology division, bangabandhu sheikh mujibur rahman agricultural university, gazipur, bangladesh 4 rice farming systems division, bangladesh rice research institute, gazipur-1701, bangladesh 5agronomy division, bangladesh rice research institute, gazipur-1701, bangladesh *corresponding author, email: smstonmoy47@gmail.com (received: 01 february 2024, accepted: 29 april 2024) keywords: hyv, nitrogen levels, brri dhan89, brri dhan100, harvest index abstract application of n fertilizer is very crucial for rice, but both excessive and mild reduced productivity. a field experiment was conducted during the boro 2021-2022 season to find out the optimum dose of n fertilizer for higher yield. the trial was conducted in a factorial rcbd design with three replications. factor a: two varieties of rice viz. brri dhan89 and brri dhan100 and b: five nitrogen levels i.e., 0, 90, 120, 150, and 180 kg ha−1. yield and yield-contributing traits varied significantly with n levels. brri dhan89 outyielded brri dhan100 due to its varietal potential and longer life cycle. the highest tiller number hill−1, panicle number hill−1, panicle length, filled grain panicle−1, grain yield, biological yield and harvest index and lowest spikelet sterility were obtained from 120 kg n ha−1 irrespective of variety. the result revealed that the combination of both varieties with 120 kg n ha−1 followed by 90 kg n ha−1 in maximizing rice productivity while avoiding excess use of n fertilizer. introduction bangladesh stands as the third-largest global producer of rice, trailing only china and india, boasting a production volume of 36 million tons (rahman et al., 2021). in bangladesh, rice cultivation is categorized into three main classes based on the seasons: aus, aman, and boro. boro rice covered largest area, encompassing over 40.91% of the total rice cultivation area of 11.828 million acres and production 19.885 million metric tons (bbs, 2022). production of rice depends many factors including variety, soil, environment, cultural practice etc. fertilizer management and time of planting also influenced grain yield (rana et al., 2023). to maximize yields on limited land resources, the application of nitrogen (n) fertilizer is crucial for modern rice cultivars. rice demand is anticipated to rise at an annual rate of approximately 1% (rosegrant et al., 2001). there's limited lands for expansion in rice cultivation areas or additional irrigated land. hence, enhancing the efficiency of n fertilizer usage to maintain economically viable input levels for boosting rice production. moreover, n fertilizer is one of the most important nutrient components for plant growth, yield as well as grain quality. applying top-dressed nitrogen during the rapid growth phase of rice can be absorbed very effectively. applying higher concentrations of n has been shown to boost both plant growth and n metabolism. in plants, applying an excess of n extends the crop's duration, leading to a reduction in the period between leaf appearance and leaf yellowing, ultimately decreasing grain yield and increasing n loss (wang et al., 2016). utilizing an appropriate n rate is crucial not just for achieving optimal economic yields but also for mitigating environmental pollution. the application of n fertilizers is crucial for unlocking the maximum yield capacity of contemporary rice cultivars (chamely et al., 2015). 42 tonmoy et al. however, the effectiveness may vary due to factors like soil fertility, fertilizer application, and crop responsiveness to nutrient inputs. moreover, excessive n application can result in ground water contamination, elevated production expenses, diminished crop yields and environmental harm (djaman et al., 2018). considering the above factors, the specific purpose of this study was to find out the optimum dose of n fertilizer for better yield performance in bogura region, bangladesh. materials and methods experimental site, design and materials in the boro (dry) season of 2021-2022, a field trial was conducted at the regional station of bangladesh rice research institute (brri) in sirajganj. the climate in the area are characterized by alternating periods of cold in seedling to maximum tillering stage and alternate hot rainy season in flowering to maturity stage. the experiment adhered to a factorial randomized complete block design (rcbd) with three replications. factor a: encompassed two high-yielding varieties of boro rice namely brri dhan89 and brri dhan100. factor b: five different levels of nitrogen viz., 0, 90, 120, 150, and 180 kg ha−1.the experimental plot was situated on medium-high elevation land with soil characterized as sandy loam. agronomic management practices the seeds were immersed in water within a bucket for duration of 24 h. and pre-germinated seeds were sown in a moist seedbed at the brri regional station in sirajganj research field on november 22, 2021. seedlings aged 45 days were transplanted with one seedling per hill asspacing was maintained at 20cm x 20cm.the experimental plot received with triple super phosphate (tsp), muriate of potash (mop), gypsum, and zinc sulphate at rates of 50, 80, 45, and 2.0 kg ha−1, respectively. the total quantities of tsp, gypsum, zinc sulphate, and two-third of mop were applied during final land preparation. nitrogen was applied according to the designated treatment in three equal split: the first top dress of n at 15 days after transplanting (dat), the 2nd at 30 dat, and the 3rd at 45 dat. while, rest one-third of mop fertilizer was applied during 3rd top dressing of urea at 45 dat. weeds were managed through the application of a pre-emergence herbicide called rifit 500 ec (pretilachlor) at a rate of 988 ml ha−1 within 5 dat. hand weeding by using a "khurpi" was also done at 25 days after transplanting for further weed management. irrigation was administered as needed until the rice reached the soft dough stage. to prevent insect infestation, the suntap plus 50wp (cartap+fipronil) insecticide was applied at a rate of 750 g ha−1 at the heading stage. throughout the experiment, fungal diseases were controlled by applying amistar top 325sc (azoxystrobin + difenoconazole) fungicide at a rate of 500 ml ha−1. data collection to record panicle length and the number of spikelets, five hills were randomly selected from each experimental plot. the plant height was measured from ground level upto the tip of the panicle after flowering. the 1000-grain weight, grain yield and straw yields were determined after harvesting. the biological yield and harvest index (%) were calculated by using the following formula: biological yield (t ha−1) = grain yield (t ha−1) + straw yield (t ha−1) harvest index (hi%) = grain yield biological yield × 100 statistical analysis all data were subjected to separate statistical analyses using the analysis of variance technique implemented in r software (versions 4.2.1, 2022) and differences among treatment means, the least significant difference (lsd) test was employed at level of 5%. results and discussion determination of optimum nitrogen level for maximizing yield of boro rice 43 effect of variety on yield and yield contributing traits there were significant different of plant height between two rice varieties. from table 1 it was observed that plant height of brri dhan89 (110.60 cm) was taller than brri dhan100 (104.62 cm). no significance difference was found in case of tiller hill−1 and panicle hill−1. between two rice varieties longest panicle length (26.71 cm), highest filled grain panicle−1 (152.59), highest unfilled grain panicle−1 (10.76), highest sterility percent (10.76), highest straw yield (8.75 t ha−1), biological yield (15.99 t ha−1) and highest hi (45.08) were observed in brri dhan89 as compared to brri dhan100. the highest grain yield (7.24 t ha−1) was observed in brri dhan89 due to its highest panicle length, filled grain panicle−1, tiller number, panicle number, panicle length. the research findings were also supported by azad et al., 2022; chakma, 2006; roy et al., 2021; roy et al., 2024; hossain et al., 2010 and dutta et al., 2002). table 1. effect of variety on yield and yield contributing traits variety yield (t ha−1) straw yield (t ha−1) biological yield (t ha−1) harvest index (%) brri dhan89 7.24 a 8.75 a 15.99 a 45.08 a brri dhan100 5.12 b 6.84 b 11.96 b 42.73 b *** *** *** lsd(0.05) 0.2740711 0.2658882 0.4265024 1.159781 cv (%) 5.782148 4.447491 3.979089 3.443713 effect of n levels on yield and yield contributing traits there was no significance difference of plant height at different n levels (table 2). the number of tillers hill−1, panicle hill−1, panicle length, filled grain panicle−1 were varied significantly due to different level of n rates (table 2). the maximum number of tiller hill−1 (11.65) was found due to application of 180 kg ha−1 n followed by n120 (11.52), n50 (11.40), and n150 (10.88). lowest number of tiller hill−1 (10.33) was found n0 treatment. higher number of panicle hill−1 (11.18) was found due to application of 120 kg ha−1 n and which was statistically similar with n180 (11.03) and n90 (10.87) and lowest was found in n0 (9.60) treatment. the maximum panicle length (26.12 cm) was observed in n180 n level and which was statistically similar with n120 n levels and lowest panicle length was observed in n0 (24.69 cm) n levels. similar result also reported by jahan et al., (2020). gewaily et al., (2018) reported that the increase in panicle number and panicle length with n fertilization. the maximum number of filled grain panicle−1 (159.70) was found in n120 n level which was statistically similar with n90 (154.03) and n150 (153.75) n level. highest number of unfilled grain panicle−1 was observed in n180 (18.80) n level while lowest in n50 (12.70) n levels. the highest sterility % was found in n180 (10.83) n level and lowest was found in n120 (7.68) n level. hence, it might be concluded that unfilled grain panicle−1 increased by increased n levels. similar result also concluded that jahan et al. (2020). the increased number of filled grain with the increase in n rates indicates that n fertilization is important for both sources and sinks development reported by jahan et al. (2020). table 2. effect of n levels on yield and yield contributing traits nitrogen level plant height (cm) number of tillers hill−1 number of panicle hill−1 panicle length (cm) number of filled grains panicle−1 number of unfilled grains panicle−1 sterility percentage (%) n0 105.28 10.33 b 9.60 c 24.69 c 126.82 c 14.35 9.34 ab n90 107.31 11.40 a 10.87 ab 25.43 b 154.03 ab 12.70 8.13 b n120 107.85 11.52 a 11.18 a 25.74 ab 159.70 a 13.37 7.68 b n150 108.47 10.88 ab 10.21 bc 25.60 b 153.75 ab 16.97 9.87 ab n180 109.14 11.65 a 11.03 ab 26.12 a 150.00 b 18.80 10.83 a 44 tonmoy et al. lsd(0.05) ns 0.8998866 0.87815 0.494504 7.702076 ns ns cv (%) 2.32 6.650724 6.84557 1.597518 4.265603 28.68612 23.8302 note: ns=non‐significant yield (t ha−1), straw yield (t ha−1), biological yield (t ha−1), and hi (%) were varied significantly due to different level of n rates (table 2.1). highest yield (7.02 t ha−1) was found in n120 due to higher tiller number hill−1, panicle length and highest number of panicle hill−1, highest number of filled grain panicle−1 and lowest percent of spikelet sterility. grain yield is influenced by various yield contributing factors as reported by jahan et al. (2020). this study also showed grain yield increased with increased n levels up to 120 kg ha−1 and after that grain yield decreased with increasing n levels. lowest yield (4.76 t ha−1) was found n0 level. the highest straw (8.33 t ha−1) yield was found due to application of 180 kg ha−1 n level and which was significantly differ from others n level. lowest straw yield (6.83 t ha−1) was found in n0 level. highest straw yield with higher n level might be due to better n uptake leading to greater dry matter accumulation and its translocation to their sink (rajesh et al., 2015). the maximum biological yield (14.92 t ha−1) was found in n120 level and which was statistically similar with others n level except n0 level. higher hi was observed in n120 (46.91) and which was statistically similar with n90 (46.41). lowest harvest index was found in n0 (41.00) and which was statistically similar with n180 (41.43). table 2.1. effect of n levels on yield and yield contributing traits interaction effects of variety and n levels on yield and yield contributing traits interaction effect of varieties and n levels did not vary plant height, tiller hill−1 and panicle hill−1 significantly (table 3). the highest number of panicle hill−1 was found in v2n90 (brri dhan100 followed by n 90 kg ha−1) while lowest was found v2n0 (brri dhan100) and n 0 kg ha−1. the interaction effect between varieties and n levels was influenced significantly by panicle length. the maximum panicle length (27.37 cm) was observed in v1n120 (brri dhan89 and n 120 kg ha−1) which was statistically similar with v1n90), v1n150 and v1n180, respectively. lowest panicle length (23.44 cm) was found in v2n90. this result supported by yoseftabar (2013) reported that the increase in panicle number and panicle length with n fertilization. the interaction effect of varieties and n levels was non-significance by the number of filled grains panicle−1, number of unfilled grains panicle−1, percent spikelet sterility and percent hi. the maximum percent of hi (47.91) was found in v1n120 followed by v1n90 and lowest hi (40.27) was in v2n0. alam et al. (2009) also reported that the interaction of variety and n had t significant effect. table 3. interaction effects of variety and n levels on yield and yield contributing traits variety × nitrogen level plant height (cm) number of tiller hill−1 number of panicle hill−1 panicle length (cm) number of filled grains panicle−1 number of unfilled grains panicle−1 sterility percentage (%) harvest index (%) v1×n0 108.45 10.47 9.73 25.66 b 131.17 17.00 11.51 41.72 v1×n90 109.77 10.60 10.33 26.83 a 156.60 16.73 9.62 47.48 v1×n120 110.40 11.63 11.33 27.37 a 163.97 14.73 8.24 47.91 v1×n150 112.13 11.07 10.30 26.80 a 157.17 19.53 10.98 45.24 nitrogen level yield (t ha−1) yield increase over control (%) straw yield (t ha−1) biological yield (t ha−1) harvest index (%) n0 4.76 d 6.83 c 11.59 b 41.00 c n90 6.72 ab 41.18 7.71 b 14.43 a 46.41 a n120 7.02 a 47.48 7.90 b 14.92 a 46.91 a n150 6.29 bc 27.76 8.01 b 14.30 a 43.75 b n180 6.10 c 26.92 8.53 a 14.63 a 41.43 c lsd(0.05) 0.43 0.42 0.67 1.83 cv (%) 5.78 4.44 3.97 3.44 determination of optimum nitrogen level for maximizing yield of boro rice 45 v1×n180 112.25 11.70 11.13 26.90 a 154.07 24.47 13.46 43.03 v2×n0 102.12 10.20 9.47 23.74 c 122.47 11.70 7.13 40.27 v2×n90 104.84 12.20 11.40 23.44 d 151.47 8.67 6.64 45.34 v2×n120 105.29 11.40 11.01 24.03 c 155.43 12.00 7.13 45.92 v2×n150 104.68 11.68 10.11 24.41 c 150.33 14.40 8.75 42.26 v2×n180 106.15 11.60 10.93 25.34 b 145.93 13.13 8.20 39.84 lsd (0.05) ns ns ns 0.70 ns ns ns ns cv% 2.33 6.65 6.85 1.60 4.27 28.69 23.83 3.44 note: ns=non‐significant the interaction effect of varieties and n levels was influenced significantly by grain yield (t ha−1) and biological yield (t ha−1) and non-significant by straw yield (fig. 1, 2, 3). fig. 1. interaction effect of varieties and n levels on yields. (where, t0=0, t1=90, t2=120, t3=150 & t4=180 kg n ha-1) the highest grain yield (8.14 t ha−1) was obtained by v1n120 (brri dhan89 and n 120 kg ha−1) combination followed by v1n90 (brri dhan89 and n 90 kg ha−1) due to higher tiller number hill−1, panicle number hill−1, panicle length, number of filled grains panicle−1, hi, and lower number of unfilled grains panicle−1 and percent spikelet sterility. the lowest yield (4.17 t ha−1) was found in v2n0 (brri dhan100 and n 0 kg ha−1). highest straw yield (9.61 t ha−1) was produced by v1n180 and lowest straw yield (6.18 t ha−1) was produced by v2n0. 46 tonmoy et al. fig. 2. interaction effect of varieties and n levels on straw yield. (where, t0=0, t1=90, t2=120, t3=150 & t4=180 kg n ha-1) highest biological yield (16.96 t ha−1) was observed in v1n120 and lowest (10.35 t ha−1) was v2n0. similar findings also reported by razib et al. (2023). the optimum n application rates for achieving maximum yield vary with both the rice cultivar and the specific growing season, highlighting the importance of tailoring n fertilization practices to the rice variety and prevailing climatic conditions (jahan et al., 2020). fig. 3. interaction effect of varieties and n levels on biological yield. (where, t0=0, t1=90, t2=120, t3=150 & t4=180 kg n ha-1) conclusion the growth and yield repercussion of rice var. brri dhan89 and brri dhan100 were varied due to application of different n levels. plant height, tiller number, panicle length, number of unfilled determination of optimum nitrogen level for maximizing yield of boro rice 47 grains and straw yield increased due to increased levels of n in both rice varieties. but number of panicle hill−1, number of filled grains panicle−1, biological yield, and hi was aptitude to increase with the increased of n levels up to 120 kg ha−1and after that decreased with increasing n levels. it elicits that over n rates did not give additional benefit regarding to grain yield. based on grain yield and yield contributing characters the order of n levels was n120>n90>n150>n180>n0. so, n level 120 kg ha−1 could be recommended in combination with recommended dose of tsp, mop, and gypsum fertilizer to assure optimum requirement of nutrient for both brri dhan89 and brri dhan100. acknowledgment authors are greatly thankful to the authorities of bangladesh rice research institute (brri), regional station, sirajganj for the assistance in conducting the experiment. references alam, m.m., m.h. ali, a.a.k.m. ruhul and m. hasanuzzaman. 2009. yield attributes yield and harvest index of three irrigated rice varieties under different levels of phosphorus. adv. biol. res. 3(3&4): 132–139. azad, a.k., u. sarker, s. ercisli, a. assouguem, r. ullah, r. almeer and i. peluso. 2022. evaluation of combining ability and heterosis of popular restorer and male sterile lines for the development of superior rice hybrids. agronomy 12(4): 965. bbs. 2022. yearbook of agricultural statistics of bangladesh. bureau of statistics, statistical division, ministry of planning, government of the people's republic of bangladesh, dhaka. chakma, s. 2006. influence of spacing on the growth and yield attributes of modern boro rice varieties. ms thesis, bangladesh agricultural university, mymensingh. chamely, s.g., n. islam, s. hoshain, m.g. rabbani, m.a. kader and m.a. salam. 2015. effect of variety and nitrogen rate on the yield performance of boro rice. progress. agric. 26(1): 6–14. djaman, k., v.c. mel, f.y. ametonou, r. el-namaky, m.d. diallo and k. koudahe. 2018. effect of nitrogen fertilizer dose and application timing on yield and nitrogen use efficiency of irrigated hybrid rice under semi-arid conditions. j. agric. sci. food res. 9(2): 223. dutta, r.k., m.a.b. mia and s. khanam. 2002. plant architecture and growth characteristics of fine grain and aromatic rice and their relation with grain yield. intl. rice comm. newsl. 51:51–56. gewaily, e.e., a.m. ghoneim and m.m. osman. 2018. effects of nitrogen levels on growth, yield and nitrogen use efficiency of some newly released egyptian rice genotypes. open agric. 3(1): 310–318. hossain, m.s., f.i. monshi, a.m.a. kamal and m.f. miah. 2010. grain yield and protein content of transplant aman rice as influenced by variety and rate of nitrogen. j. agrofor. environ. 3(2): 235–238. jahan, a., a. islam, i.u. sarkar, m. iqbal, n. ahmed and r. islam. 2020. nitrogen response of two high yielding rice varieties as influenced by nitrogen levels and growing seasons. geol. ecol. landsc. 6(1): 24–31. rahman, m., m. islam, m. rahaman, m. sarkar, r. ahmed and m. kabir. 2021. identifying the threshold level of flooding for rice production in bangladesh: an empirical analysis. j. bangladesh agril. univ. 19(2): 243– 250. rana, m.m., m.b. hossain, t.k. roy, r. shultana, m.r. hasan, u.a. naher, j.c. biswas and m. maniruzzaman. 2023. response of yield and agronomic output of bangabandhu dhan100 under varying sowing window in cold prone rangpur region. indian j. agric. res. 58(2): 259-265. razib, m.a.h., a.u. sarker, n. sultana, m.n. islam and r. podder. 2023. performance of three boro rice varieties under different levels of nitrogen application. res. agric. livest. fish. 9(3):267–278. rosegrant, m.w., m.s. paisner, s. meijer and j. witcover. 2001. global food projections to 2020: emerging trends and alternative futures. international food policy research institute, washington, dc. pp. 224. roy, t.k., sannal, a., tonmoy, s.m.m.s., akter, s., roy, b., rana, m.m., alam, z., and hasan, m.r. 2024. trait analysis of short duration boro rice (oryza sativa l.) varieties in northern region of bangladesh: insights from heatmap, correlation and pca. nova geodesia. 4(2). roy, t.k., m. hasan, s. pramanik and s. sikder. 2021. yield performance of rice varieties under nacl induced salinity stress in boro season. j. sci. technol. 19: 40–51. yoseftabar, s. 2013. effect nitrogen management on panicle structure and yield in rice (oryza sativa l.). int. j. agric. crop sci. 5(11). 1224–1227. wang, z., w. zhang, s.s beebout, h. zhang, l. liu, y. yang and j. zhang. 2016. grain yield, water and nitrogen use efficiencies of rice as influenced by irrigation regimes and their interaction with nitrogen rates. field crops res. 193: 54–69. bangladesh agron. j. 2022, 25(2): 43-49 growth and yield performance of aus rice under agronomic managements m.h. mahmud1, p.k. biswas2, m.s. islam2 and m.d. hossain3 1project implementation unit-barc, national agricultural technology program-phase-ii project, barc, dhaka1215, 2department of agronomy, sau dhaka-1207, bangladesh, 3farm superintendent, bangladesh wheat and maize research institute, regional, station, jamalpur corresponding e-mail: h.mahmud193@gmail.com (received: 02 august 2022, accepted: 22 december 2022) keywords: agronomic management, growth, yield, aus rice abstract the experiment was conducted at the experimental field of sher-e-bangla agricultural university, dhaka during the period from march to june, 2018 to study the effects of agronomic managements on growth and yield of aus rice. the experiment comprised of split –plot design where varieties in the main plots viz., i) brri dhan65 (v1) and ii) nerica (v2) and five agronomic managements in the subplots viz., i) no management-m0, ii) no weeding, but all other managements-m1, iii) no fertilizer application, but all other managements-m2, iv) no irrigation application, but all other managements-m3 and v) recommended management-m4, respectively. almost all the studied characters were found statistically significant due to variation in treatments. significant variation was recorded different yield contributing characters and yield of aus rice. at 30, 50, 70 das and harvest, the taller plant (24.61 cm, 41.27 cm, 60.23 cm and 80.28 cm, respectively), grain yield (0.96 t ha-1) and straw yields (2.75 t ha-1) were recorded from v2 compared to that of v1. similarly, the tallest plant (27.11 cm, 49.66 cm, 71.49 cm and 91.07 cm at 30, 50, 70 das and harvest, respectively), grain yield (2.34 t ha-1) and straw yield (5.30 t ha-1) were observed from m4. in respect of interaction, the highest grain yield (2.43 t ha-1) and straw yield (5.31 t ha-1) were observed from v1m4 (brri dhan65 with recommended management), while the lowest grain yield (0.12 t ha-1) from v1m0 (brri dhan65 with no management) and straw yield (0.85 t ha-1) from v2m0 (nerica with no management). irrespective of variety with no management reduced 94-95% grain yield of aus rice that was 84-89% for no weeding and no fertilizer application. introduction rice (oryza sativa l.) is the most important food in tropical and subtropical regions (singh et al., 2012). it is the staple food of more than three billion people in the world, most of who live in asia (irri, 2009). it is the driving force of bangladesh agriculture covers about two-thirds of the cultivated land and constitutes 90% of the food grain production in bangladesh (bbs, 2020). in bangladesh, the geographical, climatic and edaphic conditions are favorable for year-round rice cultivation. rice yields are either decelerating/stagnating/declining in post green revolution era mainly due to imbalance in fertilizer use, soil degradation, irrigation and weeding schedule, type of cropping system practiced lack of suitable rice genotypes/variety for low moisture adaptability and disease resistance (prakash, 2010). the average yield of rice in bangladesh is about 3.07 t ha-1 (bbs, 2018). 44 mahmud et al. appropriate agronomic management practices greatly influence the growth and yield of rice. yield loss is occurred due to improper weeds, nutrient management and irrigation schedule. therefore, these managements are a complete package for satisfactory any crop production specially rice production in bangladesh. weed free condition during the critical period of competition, recommendation doses of fertilizer application and appropriate amount of water are essential for obtaining optimum rice yield. subsistence farmers in bangladesh spend more time and energy on control of weeds; do not give proper dose of fertilizer and optimum amount of water for rice cultivation. thus, the appropriate agronomic management practices need to be adopted by the farmers for maximizing rice yield. the present research work was, therefore, undertaken to find out the effect of agronomic management on growth and yield of aus rice. materials and methods the experiment was conducted at experimental field of sher-e-bangla agricultural university (2377n latitude and 9033e longitude) which belongs to the agro-ecological zone of the modhupur tract, aez-28 (anonymous, 1988). the soil of the experimental field classified as deep red brown terrace soils in bangladesh soil classification system (undp and fao, 1988). split -plot design with three replications was followed where variety in the main plots and agronomic managements in the sub-plots. there were 10 plots of size 5.0 m × 2.0 m in each of 3 replications. there were two rice varieties viz. nerica (v1) and brri dhan65 (v2) and five agronomic managements viz. (no management-m0, no weeding, but all other managements-m1, no fertilizer application, but all other managements-m2, no irrigation application, but all other managements-m3, and recommended management-m4. seeds were sown in line in main plot after good tilt of land. the experimental area was fertilized with 120, 100, 80, 60 and 10 kg ha-1 of n, p2o5, k2o, s and zn. the entire amount of tsp, mop, gypsum and zinc sulphate were applied during the final preparation of land. half of urea was applied during final land preparation and rest half applied two equal installments at 30 das and 45 das. plant height, number of tillers hill-1 and number of leaves hill-1 were calculated from randomly pre-selected 5 hills plot-1. dry matter was recorded from the mean oven dry weight of plants from 2 hills plot-1. filled grains panicle-1 and unfilled grains panicle-1 were counted from the average number of grains from ten panicles.1000-grain weight was measured at 12% moisture content. grain yield and straw yield were determined and biological yield was calculated by summing up the grain and straw yield. harvest index refers to the ratio of economic yield to biological yield and was computed with following formula (gardner et al., 1985). all the data collected on different parameters were statistically analyzed by technique using mstatc computer package program and the mean differences were calculated using least significant difference (lsd) test at 5 % level of probability. results and discussion effect of variety plant height, number of leaves hill-1, dry matter weight hill-1 and length of panicle varied significantly and number of effective tillers hill-1 and number of non-effective tillers hill-1 statistically identical a (table 1). the higher plant height (80.28 cm) and panicle length (19.84 growth and yield performance of aus rice under agronomic managements 45 cm) was obtained from nerica whereas, the higher value of dry matter content hill-1 (8.78 g), number of effective tillers hill-1 (5.24) and number of non-effective tillers hill-1 (1.72) was found from the brri dhan65. due to genetic makeup of different varieties, plant height among the varieties might be varied (murshida et al., 2017). amin et al. (2006) revealed that the variation of dry matter among rice varieties. number of filled grains panicle-1 and number of total grains panicle-1 varied significantly where number of unfilled grains panicle-1, weight of 1000-grain, grain yield, straw yield and biological yield varied numerically for brri dhan65 and nerica (table 2). rice var. nerica produced better in all aspect of the yield and yield contributing characters viz. the number of filled grains panicle-1 (49.09), number of unfilled grains panicle-1 (27.25), weight of 1000-grain (22.51g), grain yield (0.96 t ha-1), straw yield (2.75 t ha-1), biological yield (3.71 t ha-1) and harvest index (21.52%) compared to brri dhan65. effect of agronomic management different agronomic managements showed significant differences on plant height, number of leaves hill-1, dry matter weight hill-1, number of effective tillers hill-1, and panicle length except number of non-effective tillers hill-1 (table 1). both recommended management (m4) and no irrigation but all other managements (m3) gave the highest plant (91.07 cm), dry matter content hill-1 (14.12 g) and panicle length (21.91 cm) and number of leaves hill-1 (61.13), number of effective tillers hill-1 (8.50) and non-effective tillers hill-1 (2.33) was found from recommended management (m4) individually. on the other hand, no management (m0) produced lowest in all growth parameters which are similar to no weeding. table 1. effect of variety and agronomic management on growth parameters of aus rice treatments plant height (cm) number of leaves hill-1 dry matter weight hill-1 (g) number of effective tillers hill-1 number of non-effective tillers hill-1 panicle length (cm) v1 71.80b 44.63a 8.78a 5.24 1.72 17.53b v2 80.28a 34.80b 8.31b 4.92 1.71 19.84a se (±) 0.99 1.98 0.99 ns ns 0.35 cv (%) 11.43 13.63 12.11 28.63 26.15 5.13 m0 60.31d 24.20d 4.55b 3.00c 1.00 15.41c m1 75.72b 38.30c 7.87b 3.50c 1.83 17.99b m2 66.77c 26.77d 5.39b 3.33c 1.83 17.57b m3 86.38a 48.17b 11.78a 7.00b 1.50 20.57a m4 91.07a 61.13a 14.12a 8.50a 2.33 21.91a se (±) 1.78 1.48 0.81 0.65 ns 0.73 cv (%) 14.52 9.14 13.21 21.55 27.83 6.72 brri dhan65 (v1), nerica (v2), no management -m0, no weeding but all other managements-m1, no fertilizer application but all other managements-m2, no irrigation but all other managements-m3, recommended management-m4, not significant –ns means with dissimilar letters are significantly different at p ≤ 0.05 at lsd test. different agronomic managements showed significant differences on yield and yield contributing characters (table 2). recommended management (m4) gave highest value in attributes of yield and yield contributing characters, whereas no irrigation but all other managements (m3) 46 mahmud et al. performed highest in number of unfilled grains panicle-1, and harvest index. lowest performance was obtained from no management (m0) and no weeding but all other managements (m1) in all parameters except in number of unfilled grains panicle-1 and weight of 1000grains for m1. no management reduced 94% grain yield of aus rice that followed by 87% for no weeding and 86% for no fertilizer application. without irrigation reduced 32% yield that might be due to the contribution of rainfall during the growing period. singh et al. (1999) reported that no weed management until maturity removed significantly higher amount of nitrogen through weeds (12.97 kg ha-1) and reduced the grain yield of rice by 49% compared to that of weed free crop up to 60 dat. table 2. effect of variety and agronomic management on yield and yield contributing characters of aus rice treatments number of filled grains panicle-1 number of unfilled grains panicle-1 weight of 1000 grains (g) grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) variety v1 36.58b 23.71 22.02 0.95 2.67 3.63 19.45 v2 49.09a 27.25 22.51 0.96 2.75 3.71 21.52 se (±) 2.26 ns ns ns ns ns ns cv (%) 14.46 13.73 6.71 24.59 3.21 5.11 24.70 agronomic management m0 26.33c 19.33b 20.36c 0.14c 0.94c 1.08c 12.97c m1 27.83c 29.67a 21.96b 0.31c 1.45c 1.77c 12.90c m2 33.33c 19.67b 22.31b 0.33c 1.98c 2.29c 17.51b m3 55.33b 29.17a 23.11ab 1.62b 3.87b 5.48b 28.53a m4 71.67a 29.67a 23.56a 2.39a 5.30a 7.70a 30.51a se (±) 6.20 3.10 0.51 0.24 0.37 0.58 1.37 cv (%) 25.03 21.28 3.99 22. 08 18.32 17.24 11.61 brri dhan65 (v1), nerica (v2), no management -m0, no weeding but all other managements-m1, no fertilizer application but all other managements-m2, no irrigation but all other managements-m3, recommended management-m4, means with dissimilar letters are significantly different at p ≤ 0.05 at lsd test. interaction effect interaction effect of variety and agronomic managements showed significant differences on all growth characters (table 3). the tallest plant (94.48 cm) and panicle length (22.61 cm) were observed from the nerica with recommended management which are 50.61% and 37.44% higher than no management of same variety. the highest number of leaves hill-1 (70.40), dry matter content hill-1 (14.48 g), number of effective tillers hill-1 (9.33) and number of noneffective tillers hill-1 (2.67) showed 60.41, 71.75, 71.38 50.19 and 65.72%, respectively lower performance observed from brri dhan65 with recommended management than no management.no weeding, but all management also reduced 41.66, 55.73, 64.31, 37.45 and 57.16%, respectively lower performance of same parameters. suresh kumar et al. (2016) reviewed that weed flora under transplanted condition is very much diverse and consists of grasses, sedges and broad-leaved weeds causing yield reduction of rice crop up to 76 %. growth and yield performance of aus rice under agronomic managements 47 table 3. interaction effect of variety and agronomic management on growth parameters of aus rice at harvest treatments plant height (cm) number of leaves hill-1 dry matter weight hill-1 number of effective tillers hill-1 number of non-effective tillers hill-1 panicle length (cm) v1m0 57.88f 27.87e 4.09e 2.67d 1.33bc 14.36e v1m1 70.37d 41.07c 6.41cd 3.33d 1.67a-c 16.50d v1m2 61.11ef 30.40e 4.41de 3.00d 2.00ab 16.31d v1m3 82.03c 53.40b 11.46ab 7.67b 1.00bc 19.29c v1m4 87.66b 70.40a 14.48a 9.33a 2.67a 21.20b v2m0 62.73e 20.53f 5.02de 3.33d 0.67c 16.45d v2m1 81.07c 35.53d 7.33c 3.67d 2.00ab 19.47c v2m2 72.42d 23.13f 6.39cd 3.67d 1.67a-c 18.83c v2m3 90.73ab 42.93c 10.81b 6.33c 2.00ab 21.84ab v2m4 94.48a 51.87b 13.76ab 7.67b 2.00ab 22.61a se (±) 2.543 2.09 1.14 0.63 0.57 0.73 cv (%) 5.79 9.14 25.64 21.55 57.83 6.72 brri dhan65 (v1), nerica (v2), no management -m0, no weeding but all other managements-m1, no fertilizer application but all other managements-m2, no irrigation but all other managements-m3, recommended management-m4, means with dissimilar letters are significantly different at p ≤ 0.05 at lsd test. interaction effect of variety and agronomic managements showed significant differences on yield and yield contributing characters (table 4). the highest number of filled grains panicle-1, weight of 1000grain, grain yield, straw yield, biological yield and harvest index were observed from the recommended management both the varieties except in number of unfilled grains panicle-1 for nerica and weight of 1000 grain for brri dhan65. the lowest performance gave brri dhan65 with no management combination. nerica with no management reduced number of filled grains panicle-1 (56.25%), grain yield (93.64%), straw yield (83.75%) and biological yield (86.81%) and no weeding, but all management also reduced 58.93, 32.80, 83.90, 54.50 and 63.84%, respectively from recommended management. jayadeva et al. (2009) and subha and ramana (2009) found that hand weeding at 20 and 40 dat recorded highest plant height, dry matter production, tillers m-2, nutrient uptake by crop and highest grain and straw yield of rice crop. table 4. interaction effect of variety and agronomic management on yield and yield contributing characters of aus rice treatments number of filled grains panicle-1 number of unfilled grains panicle-1 weight of 1000 grains (g) grain yield (tha-1) straw yield (tha-1) biological yield (t ha-1) harvest index (%) v1m0 20.00e 17.00ef 20.78e 0.12c 1.03de 1.15d 10.74f v1m1 25.00de 22.33de 21.62d 0.23c 1.58d 1.82cd 12.28ef v1m2 22.00de 16.33f 22.19cd 0.27c 1.32de 1.59d 15.82d v1m3 47.67c 29.67bc 22.59c 1.70b 4.12b 5.82b 28.06b v1m4 68.67ab 33.33ab 22.89bc 2.43a 5.31a 7.74a 30.38ab v2m0 32.67d 21.67d-f 19.95e 0.15c 0.85e 1.01d 15.19d v2m1 30.67de 37.00a 22.30cd 0.38c 2.38c 2.77c 13.53de v2m2 44.67c 23.00d 22.42cd 0.38c 1.58d 1.96d 19.20c v2m3 63.00b 28.67bc 23.63ab 1.53b 3.62b 5.15b 29.01ab v2m4 74.67a 26.00cd 24.22a 2.36a 5.23a 7.66a 30.65a se (±) 4.20 3.13 0.51 0.237 0.365 0.576 1.373 cv (%) 20.03 16.28 3.99 22. 08 18.32 17.24 11.61 brri dhan65 (v1), nerica (v2), no management -m0, no weeding but all other managements-m1, no fertilizer application but all other managements-m2, no irrigation but all other managements-m3, recommended management-m4, means with dissimilar letters are significantly different at p ≤ 0.05 at lsd test. 48 mahmud et al. conclusion considering the above results, it may be concluded that agronomic management had significant role in the grain yield of rice. among the treatments, variety with recommended agronomic management (var. brri dhan66 with recommended practices) gave comparable higher grain yield closely followed by var. nerica with same management. however, further experimentation will need to be executed in different agro-ecological zones with more varieties of aus rice under agronomic management to reach a specific conclusion and recommendation. references ahmed, m.r., m.a. rashid, m.s. alam, k.a. billah and f. jameel. 1997. performance of eight transplant aman rice varieties under irrigated conditions. bangladesh rice j. 8(1&2): 43-44. amin, m. r., a. hamid, r. u. choudhury, s. m. raquibullah and m. asaduzzaman. 2006. nitrogen fertilizer effect on tillering, dry matter production and yield of traditional varieties of rice. intl. j. sustain. crop prod. 1(1): 17-20. anonymous. 1988. the year book of production. fao, rome, italy. baloch, m. s., i. u. awan, h. gul and a. a. khakwani. 2006. effect of establishment methods and weed management practices on some growth attributes of rice. rice sci. 13(2): 131-140. bbs (bangladesh bureau of statistics). 2018. statistical year book of bangladesh for 2018. stat. & infor. div., min. of plan. govt. of the people's repub. of bangladesh. p. 139. bbs (bangladesh bureau of statistics). 2020. statistical yearbook of bangladesh for 2020. bureau of statistics, statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. brkb. 2017. bangladesh rice knowledge bank. retrieved from http://www.knowledgebankbrri.org/riceinban.php fao. 2006. food and agriculture organization. retrieved from: http// www.fao.org fao. 2009. food and agriculture organization. fao production yearbook, food and agriculture organization, rome, italy. 56-77. gardner, f.p., r.b. pearce and r.l. mistechell. 1985. physiology of crop plants. iowa state univ. press, powa. p.66. hossain, s. m. a and a. b. m. n. alam. 1991. productivity of cropping pattern of participating farmers. in: fact searching and intervention in two fsrdp sites, activities. 1980-1990. farming system research and development programme, bau, mymensingh, bangladesh. pp. 41-44. irri. 2009. international rice research institute. rough rice production by country and geographical region-usda. trend in the rice economy in: world rice statistics. retrieved from: www.irri.org/science/ricestat. jayadeva, h.m., s.t. bhairappanavar, p.r. somashekarappa and b.r. rangaswamy. 2009. efficacy of azim sulfuran for weed control in transplanted rice. indian j. weed sci., 41 (3&4): 172175. moorthy, b. t. s. and f. c. das. 1992. performance evaluation of tow manually operated weeders in upland rice. orissa j. agril. res. 5(1-2): 36-41. murshida, s., m.r. uddin, m.p. anwar, u.k. sarker, m.m. islam and m.m.i. haque. 2017. effect of variety and water management on the growth and yield of boro rice. progress. agric. 28(1): 26–35. growth and yield performance of aus rice under agronomic managements 49 prakash, n. b. 2010. different sources of silicon for rice farming in karnataka. paper presented in indo-us workshop on silicon in agriculture, held at university of agricultural sciences, bangalore, india, 25-27th february 2010, p.14. singh, a. k., n. chandra and r. c. bharati. 2012. effects genotypes and planting time on phenology and performance of rice (oryza sativa l.). vegetos, 25: 151-156. singh, g., r. k. singh, v. p. singh, r. nayak and r. s. singh. 1999. weed management in transplanted rice (oryza sativa) under rainfed lowland situation. indian j. agron. 44(4): 728732. subha l. c. and m. v. ramana. 2009. growth and nutrient uptake of transplanted rabi rice and weeds as influenced by different weed management practices. in: national symposium on weed threat to environment, biodiversity and agriculture productivity, tnau, coimbatore. p. 63. sureshkumar r., y. ashoka and s. ravichandran. 2016. effect of weeds and their management in transplanted rice-a review. int. j. res. appl. nat. soc. sci. 4(11): 159-174. undp and fao. 1988. land resources appraisal of bangladesh for agricultural report no. 2. agro-ecological region of bangladesh. united nations development program in food and agriculture organization, 212-221. xu, s and c. wang. 2001. study of yield attributes of some restorer and maintainer lines. intl. rice res. newsl. 26(7): 136-138. bangladesh agron. j. 2021, 24(2): 115-125 effect of sunflower crop residue on weed suppression in direct-seeded aus rice under rice – sunflower-rice cropping pattern l. khatun1, t. chakrobarty1, m.a. zaman1, m. nasim1 and s. mondal1, 2* 1 bangladesh rice research institute, gazipur-1701. bangladesh 2bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding e-mail: satyen1981@gmail.com (received: 30 november 2021, accepted: 17 december 2021) keywords: allelopathy, direct-seeded rice, sunflower residue, system productivity, weed, yield abstract in bangladesh direct-seeded aus rice is a conventional rice cultivation practice and weed infestation is a severe problem in direct-seeded rice production due to the existence of favorable environment during this period. so, by minimizing the use of herbicides and replace them with eco-friendly and environmentally sustainable herbicides based on natural plant products or allelochemicals, a factorial experiment based on randomized complete block design with three replications was performed at the research field of bangladesh rice research institute (brri), gazipur, bangladesh from july 2018 to august 2019 to evaluate effect of sunflower crop residue on weeds growth and yield of direct seeded aus rice in transplanting aman-sunflower-aus cropping pattern. weed population and weed dry weight were significantly affected by crop residues treatment. weed population was significantly lower in c3 (direct sowing of aus after 7 days of sunflower residue incorporation) treatment than the control c1 (direct sowing of aus without sunflower residue incorporation) treatment. the lowest weed dry weight (90.5 g m-2) was also obtained from c4 (direct sowing of aus after 14 days of sunflower residue incorporation). the highest reduction of grain yield was obtained from without crop residue and no weeding treatments. the highest number of effective tillers m-2 (403.33), grain panicle-1 (114.67), tillers hill-1 (16.36), and grain yield (3.32 t ha-1) were observed from the treatments where sunflower residue was incorporated and the plots that were weed free. results of this study indicate that sunflower residues showed potentiality to inhibit weed growth and it has a significant effect on the yield and yield parameters of direct seeded rice. again weeds played a significant role in the reduction of yield of direct seeded rice. thus, sunflower residues might be substitute for weed management practice as well as obtaining higher yield of direct seeded rice. introduction bangladesh has three rice growing seasons: aus, aman and boro which cover about 9.6, 48.82 and 41.58% of total rice area and these contribute to 7.63, 38.62 and 53.74% of the total rice production respectively (bbs, 2019). boro is the most important and single largest crop in bangladesh in respect of volume of production. due to higher weed infestation problem, farmers don’t like to cultivate aus rice specially direct seeded aus rice. seasonal variation was also observed in the yield losses caused by weeds, with estimated rice yield losses dueto weeds at 70-80%, 30-40% and 22-36% in aus rice, transplanted aman rice and boro rice, respectively (mamun, 1990). yield loss in direct seeded rice is about 40-100% (mazid et al., 2001; ahmed and chauhan, 2014; mondal et al., 2020). with a substantial yield loss due to weed in direct seeded aus rice, manual weeding is becoming less effective because of labor crisis at critical times and mailto:satyen1981@gmail.com 116 khatun et al. increased labor costs. due to labor scarcity and lack of proper technologies, chemical weed control is becoming popular than hand weeding (ahmed et al., 2011; hasanuzzaman et al., 2008). chauhan et al. (2015) was found that even after the application of pre and post-emergence herbicides, it was not enough to achieve adequate weed control in direct seeded rice. to overcome the problems related to herbicides, use of allelopathic strategies is an alternative way in weed management for sustainable agriculture (narwal, 1997).the application of the allelopathic properties of some crops (e.g. sunflower) has been suggested for weed management due to the possibility of reducing the application of expensive, pollutant synthetic herbicides (belz, 2007; kruse et al., 2000). as a tool for biological weed control in crop production, allelopathy may be natural technique (cheema and khaliq, 2000; heidarzadeh et al., 2010). even in alley cropping system direct seeded aus rice is a good practice to uphold rice yield, minimizing weed infestation and soil health improvement through incorporation of pruning materials (mondal et al., 2013). considering the above point of view, the present study was conducted to determine the allelopathic and residual potential of sunflower towards weeds and yield performance of direct seeded rice. materials and methods the experiment was carried out at the research farm of bangladesh rice research institute (brri), gazipur, bangladesh in medium high land during july 2018 to august 2019 (aman-2018 to aus 2019). the experimental field belongs to the agro-ecological zone -28 (madhupur tract). soil texture was clay loam. the experiment was executed in factorial randomized complete block design with three replications. the treatments were: factor a: time of crop residue incorporation: c1: direct sowing of aus without sunflower residue incorporation, c2: direct sowing of aus immediately after sunflower residue incorporation, c3: direct sowing of aus after 7 days of sunflower residue incorporation and c4: direct sowing of aus after 14 days of sunflower residue incorporation and factor b: weeding: w1: weeding and w2: no weeding. the experiment was conducted under t. aman (var. brri dhan71)-sunflowerds (direct seeded) aus (var. brri dhan83) cropping pattern to determine the effect of sunflower residue incorporation on weed scenario in direct seeded aus rice and the system productivity of the following pattern. the seed of aman rice was sown in the first week of july 2018 and twenty-five days old seedlings of transplantingamanrice var. brri dhan71 were transplanted on using 2-3 seedlings hill-1 at a spacing of 20 × 20 cm and harvested at last week of november 2018. sunflower var.bari sunflower-2 were sown at a depth of 1 cm in december 2018. seeds were planted with inter-row and interplant spacing of 50 and 25 cm, respectively. a basal dose of 180 urea, 160 triple super phosphates, 150muriate of potash and 150 kgha-1was applied in each plot. plots were irrigated as per necessary for sunflower. after 90 days of sowing, mature sunflower plants were decapitated. remaining vegetative parts were uprooted, chopped into 3-5 cm to incorporate in the soil by ploughing in the recommended plot as per treatment. direct seeded aus rice var. brri dan83 (growth duration 103 days) was selected. seeds were sown continuously by maintaining 20 cm line to line distance according to the treatment at three dates (29 march 2019, 4 april 2019 and 11 april, 2019) and after sowing irrigation were ensured for germinating the seed. the recommended dose of chemical fertilizers was: 150 urea, 52 triple super phosphate and 75 kgha-1 muriate of potash. growth and yield attributes of rice in case of t. aman rice the crop cut area was 6 m2 for grain yield measurement and 4 hills from three different place (4 hills × 3=12 hills) of the plot were taken for obtaining yield attributing characters of effect of sunflower crop residue on weed suppression in direct-seeded aus rice 117 rice. the data were recorded on grain weight (kg), straw weight (kg), moisture percentage (%), tiller number hill-1, panicle number hill-1, grain panicle-1, unfilled spikelet panicle-1, thousand grain weight (g). in aus season data on weed parameters at 40 and 55 days after sowing the rice and alsorecorded on grain weight (kg), moisture percentage (%), tiller number hill-1, effective tiller m-2 and filled spikelet panicle-1. biological yield was calculated by using following formula. biological yield= grain yield + straw yield. growth and yield attributes of sunflower plant height (cm), stem diameter (cm), capitulum diameter (cm), number of seeds per capitulum, thousand seed weight and total seed weight (kg) of the plot were recorded. weed density and dry matter production weed samples were collected from prefixed location of 1 m × 1m area in each plot. collected weeds were separated into grass, sedge and broadleaf and were expressed in number m-2. after counting the weeds were firstly dried in shade for removing extra moisture and then oven dried at 70 °c for 48 h and weighed (g). statistical analysis all data were statisticallyanalyzed through star (statistical tools for agricultural research) statistical package and treatment means were compared by lsd test at 5% level of significance. results yield and yield component of aman rice (brri dhan71) there was no significant difference among the treatments in case of tiller, panicle number hill-1 filled spikelets and 1000grain weight. table 1. effect of weeding and crop residue of sunflower on yield component of aman rice, brri dhan71 crop residue of sunflower weeding (w1) no weeding (w2) tiller no. hill-1 panicle no.hill-1 filled spikelets panicle-1 (no. thousand grain wt. (g) tiller no. hill-1 panicle no.hill-1 filled spikeletspanicle-1 (no.) thousand grain wt. (g) c1 9.58 8.01 87.19 24.08 9.00 8.25 86.03 24.22 c2 10.33 9.58 83.82 24.04 10.55 9.75 87.09 23.87 c3 12.00 11.67 86.58 24.23 11.89 10.02 84.73 24.17 c4 13.01 12.23 87.18 24.05 12.33 11.11 86.37 24.25 lsd(0.05) ns ns ns ns ns ns ns ns cv (%) 1.70 1.47 4.79 0.83 1.70 1.47 4.79 0.83 ns=not significant grain yield and biological yield of brri dhan71 grain yield and biological yield of brri dhan71 showed insignificant difference among the treatments. on an average brri dhan71 gave similar yield and biological yield in all the treatments (fig.1). 118 khatun et al. fig. 1. variation in grain yield and biological yield influenced by sunflower crop residue and weeding. yield and yield component of sunflower there was no significant difference in case of plant height among the treatments. stem diameter showed statistically significant difference among the treatments. the highest stem diameter (2.38 cm) was recorded in c1w2 followed by c4w1 (2.28 cm) treatment and the lowest value in c4w2 (1.33 cm) followed by c3w2 (1.51 cm) treatment (table 2). maximum capitulum diameter (22.67 cm) was found in c1w2 treatment followed by c2w1 (20.67 cm) and c4w1 (19.67 cm) and minimum capitulum diameter (8.00 cm) was recordedin c4w2 treatment (table 2). maximumnumber of seeds per capitulum (546.67) was found in c4w1 treatment followed by c1w2 (520.00), c2w1 (446.67) and c2w2 (446.6) where minimumnumber of seeds per capitulum (246.67) was in c1w2 followed by c4w2 (313.33) treatment (table 2). maximum value of thousand seeds weight(67.33 g) was found in c4w1 followed by c3w2 (65.66 g) and c4w2 (65.00 g) and minimum thousand seeds weight(67.33 g) was registered in c3w1 (62.33 g) followed by c1w2 (62.66 g) (table 2). the maximumseed yield was found in c1w2 (2.43 tha-1) treatment followed by c4w1 (2.32 tha-1) and c2w1 (2.14 tha-1) and lowest yield (1.46 tha-1) was recorded in c2w2 treatment (table 2).maximum yield of sunflower (2.43 t ha-1) was observed in c1w2 treatment followed by c4w1 (2.32 t ha-1) and c2w1 (2.14 t ha-1) treatments. minimum yield (1.46) was in c2w2 followed by c4w2 (1.68 t ha-1) treatment (table 2). table 2. effect of weeding and crop residue of sunflower on yield and yield componentof sunflower crop residue of sunflower weeding (w1) no weeding (w2) plant height (cm) stem diameter (cm) capitulum diameter (cm) no.of seeds per capitulum 1000 seed wt.(g) seed yield (tha-1) plant height (cm) stem diameter (cm) capitulum diameter (cm) no. of seeds per capitulum 1000seed wt. (g) seed yield (tha-1) c1 105.00 1.78 13.33 246.67 63.00 1.75 116 2.38 22.67 520.00 62.66 2.43 c2 113.00 1.85 20.67 466.67 64.33 2.14 113 2.11 14.33 446.6 63.66 1.46 c3 119.33 2.03 15.00 396.00 62.33 1.75 116 1.51 10.33 396.67 65.66 1.97 c4 103.33 2.28 19.67 546.67 67.33 2.32 127 1.33 8.00 b 313.33 65.00 1.68 0 5 10 15 20 25 30 grainyield (t ha-1) biological yield(t ha1) grainyield (t ha-1) biological yield (t ha-1) weeding (w1) no weeding (w2) y ie ld ( th a -1 ) c1 c2 c3 c4 effect of sunflower crop residue on weed suppression in direct-seeded aus rice 119 lsd(0.05) ns 0.56 6.18 167.23 ns 0.51 ns 0.56 6.18 167.23 ns 0.51 cv (%) 9.12 6.12 10.45 9.45 3.73 9.26 9.12 6.12 10.45 9.45 3.73 9.26 ns=not significant weed scenario the experimental field was infested with the naturally occurring weed community including grass, broad leaved and sedge weeds. the weed composition of the plots is presented in table 4. the most dominant weed species (on the basis of density) encountered in the weedy plots at 40das. number of grasses differed significantly among the treatments. the highest number of grasses (45.33 and 65.00 m2) was observed in the treatments where no sunflower residue was incorporated (c1w1 and c1w2 respectively) and lowest number of grasses (13.67 and 23.33 m-2) was recorded in the treatment where aus rice was sown 7 days after the incorporation of sunflower residue (c3w1 and c3w2 respectively) (table 3). the highest number of sedges m-2 was registered in c2w1 (254), c4w1 (250) and c4w2 (398) which were statistically different from other treatments and the lowest number of sedges m-2 in c1w1 (215) treatment followed by c3w1 (226) and c3w2 (230) treatments (table 3). the highest number of broadleaved weed m-2 was found in c1w2 (20.67) treatment followed by c1w1 (20.33) and the lowest in c3w1 (10.00) (table 3).there is no significant difference of dry weight and fresh weight of weeds among the treatments.the effect of crop residue on fresh weight and dry weight of weeds in ricesunflower-rice cropping pattern was statistically significant. incorporation of sunflower residue significantly reduced fresh weight and dry weight of weeds. the highest value (660.01 g m-2) of fresh weight of weeds was registered in c1 treatment and the lowest (535.03 g m-2) value was in c4 treatments. the highest value (205.02 g m-2) of dry weight was recorded in c1 treatment which was statistically different from others and the lowest value (125.33 g m-2) was in c4 treatment (fig. 2). table 3. effect of sunflower crop residue on the growth, plant population and dry matte production of weeds crop residue weeding (w1) no weeding (w2) no. of grass m-2 no. of sedge m2 no. of broadleaf m-2 fresh wt. of weed (g m-2) dry wt. of weed (g m-2) no. of grass m2 no. of sedge m-2 no. of broad leaf (m-2) fresh wt. of weed (g m-2) dry wt. of weed (g m-2) c1 45.33 215.00 20.33 590.02 180.01 65.00 273 20.67 730.12 230.03 c2 31.67 254.00 13.67 570.23 170.06 41.00 319 14. 67 710.20 190.05 c3 13. 67 226.00 10.00 440.32 100.05 23.33 230 14.00 630.11 180.15 c4 24.33 250 .00 11.33 400.04 90.50 36.67 398 16.00 670.02 160.21 lsd(0.05) 3.78 14.48 3.10 54.80 23.80 3.78 14.48 3.10 54.80 23.80 cv (%) 6.15 3.50 11.72 10.56 11.78 6.15 3.50 11.72 10.56 11.78 120 khatun et al. fig. 2. effect of sunflower crop residue on fesh and dry weight of weeds in rice-sunflower-rice cropping pattern. yield and yield parameters of aus rice in rice-sunflower-rice cropping pattern sunflower residue incorporation at different time in combination with the weeding treatments was no significant effect on plant height at harvest. (table 4). data presented in table 1 revealed that there were no significant effects on effective tiller m-2 among the treatments combination. there was no significant difference among the treatments in case of number of tillers hill-1(table 4). grains per panicle showed insignificant different among the treatments. maximum number of filled spikeletspanicle-1(114.67) was observed in c2w1 followed by c3w1 (113.67) treatment and minimum number of filled grains panicle-1(114.67) was found in c1w2 (75.33) treatment (table 4).there was no significant difference among various treatments combination (table 4). table 4. yield and yield parameters of aus rice (var. brri dhan83) in rice-sunflower-rice cropping pattern crop residue of sunflower weeding (w1) no weeding (w2) plant height (cm) effective tiller m-2 (no.) tillers hill-1 (no.) filled spikelets panicle-1 (no.) grain yield (tha-1) plant height (cm) effective tillers m-2 (no.) tillers hill-1 (no.) filled spikelets panicle-1 (no.) grain yield (tha-1) c1 99.00 385.00 13.67 105.00 2.75 97.67 262.33 4.67 75.33 1.72 c2 103.67 403.33 16.33 114.67 3.21 98.33 269.67 5.67 93.67 2.39 c3 104.00 394.00 15.67 113.67 3.32 98.67 316.33 6.00 86.67 2.26 c4 102.67 267.83 13.33 102.33 3.00 99.33 265.33 4.33 88.33 1.99 lsd(0.05) ns 73.79 2.03 6.78 0.21 ns 73.79 2.03 6.78 0.21 cv (%) 5.05 9.16 8.33 7.95 9.53 5.05 9.16 8.33 7.95 9.53 ns=not significant effect of crop residue on filled spikeletspanicle-1andgrain yield (t ha-1)of aus rice crop residue incorporation of sunflower had significant effect on filled spikelets panicle-1 and grain yield (t ha-1) of aus rice. the highest filled spikeletspanicle-1 (104.17) was observed in the treatment where aus rice was sown immediately after the incorporation of sunflower residue (c2) which was 660.07 640.22 535.22 535.03 205.02 180.01 140.1 125.33 0 100 200 300 400 500 600 700 c1 c2 c3 c4 f re sh a n d d ry w e ig h t o f w e e d s (g m -2 ) sunflower crop residue fresh weight of weeds (gm-2) dry weight of weeds (gm-2) effect of sunflower crop residue on weed suppression in direct-seeded aus rice 121 statistically identical with the treatment where aus rice was sown seven days after the incorporation of sunflower residue (c3) and lowest value (90.17) was noted where no residue was incorporated (fig. 2). grain yield of rice was significantly influenced by crop residue incorporation of sunflower at different time. the highest grain yield (2.80 t ha-1) was found in (c2) which was statistically similar with the treatment c3 (1.79 t ha-1). the lowest grain yield (2.23 t ha-1) was noted in the treatment (c1) where no residue was incorporated (fig. 3).effective tillers m-2, tillers hill-1, filled spikelets panicle-1 and yield (t ha-1) of aus were significantly affected by weed management practices. the highest value of effective tillers m-2 (362.54), tillers hill-1 (14.75), filled spikelets panicle-1 (108.92) and yield (3.07 t ha-1) of aus was found in weeding plot and lowest was in no weeding plot (fig. 4). fig. 3. effect of crop residue on filled spikelets panicle-1 and yield of aus rice in rice-sunflower-rice cropping pattern. fig. 4. effect of weeding on effective tillers m-2, tillers hill-1, filled spikelets panicle-1 and yield of aus in rice-sunflower-rice cropping pattern. rice equivalent yield (rey) of the cropping patterns 90.17 104.17 100.17 95.33 2.23 2.8 2.79 2.49 0 10 20 30 40 50 60 70 80 90 100 110 c1 c2 c3 c4 f il le d s p ik e le ts p a n ic le -1 sunflower crop residue filled spikelets panicle-1 yield (t ha-1 ) 362.54 14.75 108.92 3.07 278.42 5.17 86 2.09 0 50 100 150 200 250 300 350 400 effective tiller m-2 tiller hill-1 filled spikelets panicle-1 yield (t ha-1 ) g ro w th p a ra m e tr s a n d y ie ld a tt ri b u te s weeding weeding (w1) no weeding (w2) 122 khatun et al. there was no significant difference in rey among the treatments. the highest rey was registered in c4w1 (19.31 t ha-1) followed by c2w1 (18.78 t ha-1) and c1w2 (18.65 t ha-1) treatments and the lowest in c2w2 (14.83 t ha-1) treatment (table 5). table 5. rice equivalent yield(t ha-1) of rice-sunflower-rice cropping pattern crop residue of sunflower weeding (w1) no weeding (w2) c1 16.51 18.65 c2 18.78 14.83 c3 16.88 16.86 c4 19.31 15.32 lsd(0.05) ns ns cv (%) 12.05 12.05 discussion among the sunflower residue treatments, the significantly higher number of weeds (grass and broadleaf) was recorded in the plots (45.33 and 20.33 m-2 respectively) which were not treated with sunflower residue incorporation and the lowest value of weeds (grass and broadleaf) in c3w1 (10.00 m2) and c3w2 (14.00 m-2) treatment where aus seeds were directly sown after seven days of sunflower residue incorporation. there was significant reduction of weed number in sunflower residue incorporated plot. this might be due to inhibition of weed growth by allelopathic effect of sunflower residue. sunflower rhizosphere soil reduces the seedling growth (population, plant height) and yield attributes (seed and biomass) of p. hysterophorus and trianthemaportulacastrum weeds in pot experiments. the effect of such soil was due to the presence of allelochemicals (p-hydroxybenzoic acid, vanillic acid, caffic acid, ferulic acid) released by sunflower roots in soil (rawat et al., 2011). sarkeret al. (2020) also found the highest weed population (9.67 m-2) with no sunflower crop residues and the lowest weed population (1.67 m-2) was found in the treatments where 2.0 t ha-1 of sunflower crop residues was used in transplanted aman rice and also reported that application of sunflower residues reduce weed. allelopathic effects of sunflower on other crops and weeds are well established in the literature (mahmood et al., 2013). again the effect of crop residue on fresh weight and dry weight of weeds was significant. the highest value of fresh weight (660.01 g m-2) was found in c1 (direct sowing of t. aus without sunflower residue incorporation) and dry weight (205.02 g m-2) was found in c1 treatment and lowest value of fresh weight (535.03 g m-2) and dry weight (125.33 g m-2) was in c4 (direct sowing of t. aus after 14 days of sunflower residue incorporation ) treatment followed by c3 (direct sowing of t. aus after 7 days of sunflower residue incorporation) treatment. similar trend in weed dry weight was observed by sahoo et al. (2020). they reported that significantly lower weed dry weight was recorded in the sunflower residue incorporation plot (69.7 g m-2) which was lesser than sunflower residue removal (71.1 g m-2) and control (73.6 g m-2) at 40 days after sowing/transplanting. maximum plant height (104.0 cm) of aus rice was found in c3w1 treatment followed by c2w1 (103.67 cm) andc4w1 (102.67 cm) while shortest (99.0 cm) was found in c1w1 treatment (control) followed by c1w2 (97.67 cm),c2w2 (98.33 cm),c3w2 ( 98.67 cm) and c4w2 (99.33 cm). the highest number of effective tiller m-2 (403.33) was registered in c2w1 treatment followed by c3w1 (394.00) and c1w1 (385.00) treatments. the lowest number of effective tiller m-2 (262.33) in c1w2 treatment followed by c4w2 (265.33) treatments. islam et al., (2018) reported the lowest number of effective tiller hill–1 due to the severe crop weed competition in the weedy treatment whereas, the highest number was found in weed free treatment because of no crop-weed competition in t. aman rice. the highest number of panicles m-2 (305.00) was recorded from weed free plots by manual weeding in transplanted rice (tanu et al. 2020). maximum number of tiller hill-1 (16.36) was found in effect of sunflower crop residue on weed suppression in direct-seeded aus rice 123 weed free treatment (c2w1) followed by c3w1 (15.67). the highest number of tiller hill-1 may be due to the reduction of inter species competition between crop and weed thus facilitated efficient utilization of resources viz., sunlight, nutrient and moisture to produce effective tillers. the lowest tiller hill-1 (4.33) was in weed containing treatment (c4w2) followed by c1w2 (4.67) treatment. again the highest number of filled spikelets panicle-1 (114.67) was observed in c2w1 followed by c3w1 (113.67) treatment and minimum number of filled spikelets panicle-1 (75.33) was found in c1w2 treatment. the reason for higher plant height, more number of effective tiller m-2 and filled spikelets panicle-1 in the weed free treatments might be due to the fact that there was lower weed-crop competition in terms of dry matter production of weeds as well as good source sink relationship which allowed the crop to absorb the required amount of nutrient, water and sunlight for its growth, production of panicles m-2 and grains panicle-1. the highest number of grains panicle-1 (120.78) was recorded in weed-free treatment and weedy check treatment gave the lowest no. of grains panicle-1 (78.85) in transplanted rice by tanu et al. (2020). these results are also the substantiating with the results of acharya and bhattacharya (2013). the highest yield (3.32 t ha-1) was observed in c3w1 treatment followed by c2w1 (3.21 t ha-1) treatment and lowest yield was recorded in c1w2 (1.72 t ha-1) treatment followed by c4w2 (1.99 t ha-1) treatment. from the yield data it was observed that in all cases maximum yield was observed in weed free condition and the lowest was in weed containing treatments. crop residue incorporation of sunflower had significant effect on filled spikelets panicle-1 and yield (t ha-1) of aus rice. the highest filled spikelets panicle-1 (104.17) and yield (2.80 t ha-1) of aus rice was observed in c2 (direct sowing of t. aus immediately after sunflower residue incorporation) treatment and lowest was in c1 (direct sowing of t. aus without sunflower residue incorporation) treatment. sarker et al. (2020) also found maximum number of grains panicle-1 (141.7) by using sunflower crop residues at 2.0 t ha-1 in transplanted aman rice and the lowest number of grains panicle-1 (66.83) was produced by no crops residues treatment. the highest numbers of tillers hill-1, numbers of grains panicle-1, 1000-grain weight, grain yield and straw yield were observed where wheat crop residues were incorporated @ 2.0 t ha-1 (ferdousi et al., 2017). effective tiller m-2, tiller hill-1, filled spikelets panicle-1 and yield (t ha-1) of aus were significantly affected by weed management practices. the highest value of effective tiller m-2 (362.54), tiller hill-1 (14.75), filled spikelets panicle-1 (108.92) and yield (3.07 t ha-1) of aus was found in weeding plot and lowest was in no weeding plot. bhurer et al. (2013) reported that weed control treatments significantly increased the number of paniclesm-2, panicle weight, filled grains/panicle and thousand grain weight. conclusion results of the present study reveal that application of sunflower residue reduces weed infestation and it has positive effect on yield and yield attributes of rice. therefore, sunflower residues could be a prospective weed control tool for crop production in modern agricultural science. so, further study is neededon this regard for several yearsto draw a better conclusion on yield performance of different crops, weed status and soil health. references acharya, s.s. and s.p. bhattacharya. 2013. comparative efficacy of pyrazosulfuron ethyl and bentazon with acetamides for weed control in transplanted boro rice (oryza sativa) in the lower gangetic plain zone of west bengal, india. intl. j. bio-resour. stress mng. 4(4): 506509. ahmed, s. and b.s. chauhan. 2014. performance of different herbicides in dry-seeded rice in bangladesh.the scientific world journal (3):729418. doi:10.1155/2014/729418. https://www.researchgate.net/journal/the-scientific-world-journal-1537-744x http://dx.doi.org/10.1155/2014/729418 124 khatun et al. ahmed, s., m.r. islam, m.m. alam, m.m. haque and a.j.m.s. karim. 2011. rice production and profitability as influenced by integrated crop and resources management. eco-friendly agriculture. 11: 720-725. bbs (bangladesh bureau of statistics) .2019. statistical year book of bangladesh, bureauof statistics division, ministry of plan, government people's republic of bangladesh, dhaka. pp.140-144. belz, r.g. 2007. allelopathy in crop/weed interactions an update, pest manag. sci. 63:308–326. bhurer, k.p., d.n. yadav, j.k. ladha, r.b. thapa and k. pandey. 2013. effect of integrated weed management practices on performance of dry direct seeded rice (oryza sativa l.). agron. j. nepal. 3. chauhan, b.s., s. ahmed, t.h. awan, k. jabran and s. manalil. 2015. integrated weed management approach to improve weed control efficiencies for sustainable rice production in dryseeded systems. crop protection.71: 19-24. https://doi.org/10.1016/j.cropro.2015.01.012. cheema, z.a. and a. khaliq. 2000. use of sorghum allelopathic properties to control weeds in irrigated wheat in a semi-arid region of punjab. agr.ecosyst. environ. 79: 105-112. ferdousi, s., m.r. uddin, m. begum, u.k. sarker, m.n. hossain and m.m.i. hoque. 2017. herbicidal activities of wheat residues in transplant aman rice. prog. agric. 28:253-261. https://doi.org/10.3329/pa.v28i4.36364. hasanuzzaman, m., o. islam and s. bapari. 2008. efficacy of different herbicides over manual weeding in controlling weeds in transplanted rice. australian j. crop sci. 2(1):1824. heidarzade, a., h. pirdashti and m. esmaeili. 2010. quantification of allelopathic substances and inhibitory potential in root exudates of rice (oryza sativa) varieties on barnyardgrass (echinochloa crus-galli l.). plant omics j. 3:204-209. islam, a.k.m.m., m.a.u.h. hia, s.k. sarkar and m.p. anwar. 2018. herbicide based weed management in aromatic rice of bangladesh. j. bangladesh agric. univ. 16(1): 31–40. kruse, m., m. strandberg and b. strandberg. 2000. ecological effects of allelopathic plants. a review, department of terrestrial ecology, silkeborg, denmark, rep. no. 315. mahmood, k., a. khaliq, z.a. cheema and m. arshad. 2013. allelopathic activity of pakistani wheat genotypes against wild oat (avenafatua l.). pak. j. agri. sci. 50: 169-176. mamun, a.a. 1990. weeds and their control: a review of weed research in bangladesh. agricultural and rural development in bangladesh. japan intl. cooperation agency, dhaka, bangladesh. jsard. 19: 45-72 mazid, m.a., m.a. jabber, c.r. riches, e.j.z. robinson, m. mortimer and l.j. wade. 2001. weed management implications of introducing dry-seeded rice in the barind tract of bangladesh. proc. brighton crop protection conf.-weeds, bcpc, farnham, surrey, uk. mondal, s., m.g. miah, n.e. elahi, m.a. saleque and a. rahman.2013. effect of nitrogen levels and gliricidia sepium alley widths on rice based agroforestry systems. bangladesh rice j. 17(1&2): 26-32. mondal, s., m.i.r. khan, s. dixit, p.c.s cruz, e.m. septiningsih and a.m. ismail. 2020. growth, productivity and grain quality of ag1 and ag2 qtls introgressionlines under flooding in directseeded rice system.field crop res. 248: 1-12. narwal, s.s. 1997. allelopathy and its practical use for weed management. lecture delivered at expert consultation group meeting on weed ecology and management. food and agriculture organization, rome, italy. rawat, l.s., s.s. narwal, h.s. kadian and v.s. negi. 2011. allelopathic effects of sunflower (helianthus annuus) on germination and growth of parthenium hysterophorus, allelopathy j. 27(2):225-236. sahoo, t.r., r.k. paikaray, b. beheraand s.n. jena.2020. effect of sunflower residue incorporation, method of establishment and nutrient management on weed population and dry matter in rice. j. pharmaco. phytochem. 9(2): 939-941. https://doi.org/10.1016/j.cropro.2015.01.012 https://doi.org/10.3329/pa.v28i4.36364 effect of sunflower crop residue on weed suppression in direct-seeded aus rice 125 sarker, b.s., m.r. uddin, m.p. anwar, u.k. sarker and s. rasul. 2020. effect of sunflower crop residues on weed management in transplanted aman rice. j. bangladesh agril. univ. 18(3): 557– 564.https://doi.org/10.5455/jbau.18316 issn 1810-30. tanu, s.s., p.s. biswas, ahmed and s.c. samanta.2020. effect of sunflower residues and herbicide on weed suppression, grain yield and economics of transplanted aman rice. bangladesh agron. j. 23(1): 47-58. https://doi.org/10.5455/jbau.18316%20issn%201810-30 ahmed, s. and b.s. chauhan. 2014. performance of different herbicides in dry-seeded rice in bangladesh.the scientific world journal (3):729418. doi:10.1155/2014/729418. bangladesh agron. j. 2021, 24(1): 129-138 foliar application of boron and irrigation levels on the performance of lentil s. paul1, s.c. sarker2, t.s. roy3, r. chakraborty4,m. roy5 and m. a. islam6 1ms student,2,4assistant professor,3professor, department of agronomy, 5ms student, department of agroforestry and environmental science and 6ms student, department of genetics and plant breeding, sher-e-bangla agricultural university, dhaka 1207. corresponding e-mail: shimul@sau.edu.bd (received: 05 may 2021, accepted:18 may 2021) keywords: boron, splitting, irrigation, lentil, yield. abstract the experiment was conducted to study the response of lentil to irrigation levels and different methods of boron application in relation to yield and yield contributing characters. three levels of irrigation viz., i0: control (no irrigation), i1: one irrigation at 25 days after sowing (das), i2: two irrigations at 25 das and 40 das, and four levels of boron viz., b0: control (no boron), b1: 80% recommended dose (rd) as basal + rest 20% as a foliar spray (fs) at pre-flowering (pf), b2: 60% rd as basal + rest 40% as fs at pf, b3: 40% rd as basal + rest 60% as fs at pf as treatment variables. it was found that the highest number of pods plant-1, number of seeds pod-1, 1000-seed weight, pod length, seed yield and stover yield was obtained with two irrigations. in contrast, b3 had a significant effect on the yield contributing characters of lentil. results also revealed that numerically more seed yield (638.23 kg ha-1) was recorded in i2b3. similar trend was found in case of stover yield (751.26 kg ha-1) and biological yield (1389.4 kg ha-1) from i2b3 combinations. these results suggested that combined application of irrigation at 25 and 40 das and boron at 40% rd as basal + rest 60% as fs at pf significantly enhanced the crop yields of lentil. introduction in bangladesh, 176,633 metric tons of lentils from an area of 385399 million hectares were produced during 2017-2018 (bbs, 2018). the poor fertility of the soil and not use of manures and proper fertilizers are considered to be the key reasons for reduced yield of lentil. physiological processes of plants such as photosynthesis, cell growth and turgidity, etc., are affected directly or indirectly by irrigation (reddi and reddi, 1995).water stress can affect leaf area growth, flowering, pod setting and resulting in low yield. in the growing stage, insufficient water supply can decrease crop quantity and quality (debaeke and aboudrare, 2004). vegetative stage, pre-flowering stage and pod setting stage are critical periods for water use in the lentil cycle. the considerable rise in lentil yield characteristics can be accomplished by using irrigation water, though most farmers in bangladesh do not use irrigation water both in pulses and lentils (quah and jafar, 1994). the plants require smaller amounts of micronutrients but must be available to plants for better growth and production. boron (b) is an important for plant growth, development and quality (pilbeam and kirkby, 1983; marschner, 1995; brown et al., 1999; dordas et al., 2007). boron also plays a large role in sugar exchange, nitrogen fastening, protein synthesis, sucrose mailto:shimul@sau.edu.bd 130 paul et al. synthesis, cell wall formation, membrane stability and k+ movement (singh et al., 2014). boron soil deficiency is a major cause of lower crop yields in bangladesh, india, nepal and china (anantawiroon et al., 1997). boron deficiency results in plant sterility due to malformation of the reproductive tissue that affects pollen germination, resulting in increased flower fall and reduced fruit area (subasinghe et al., 2003). irrigation and micronutrient like boron management are very important for maintaining lentil production in dry and nutrient-deficient soil. thus, the present study was initiated to assess the effects of irrigation and boron on yield performance of lentil. materials and methods the experiment was conducted during from november 2018 to march 2019 at agronomy research field, sher-e-bangla agricultural university, dhaka-1207. the soil of the research field was slightly acidic, with low organic matter content before sowing. lentil var. bari mashur 6 seeds were sown on november, 2018. the experiment was laid out in a split-plot design where irrigation treatments in main plot:viz., control (i0)(no irrigation), one irrigation (i1) at 25 days after sowing (das), two irrigations (i2) at 25 and 40 das and boron application viz., b0 = 0 kg b/ha (control), b1=80% recommended dose of b as basal + rest 20% as foliar spray (bf) at pre-flowering (pf), b2 = 60% rd of b as basal + rest 40% as fs at pf, b3= 40% rd of b as basal + rest 60% as fs at pf in sub-plot. the size of each unit plot was 2.5m 1.5m. the land was fertilized with urea-tsp, mop-boric acid @ 50-90 – 40-8.5 kg ha-1, respectively. total urea, tsp and mop were applied as a basal dose. boron was applied as boric acid as basal dose and rest amount was applied as a foliar application at before flowering stage. the seeds were treated with autostin50 wp (carbendazim group) before sowing to control the seed-borne diseases. the seeds were sown in rows in the furrows having a depth of 2-3 cm. row to row distance was maintained 30 cm. data on yield parameters were recorded and analysed using a computer-operated program mstat-c, and treatments means were estimated by the duncan multiple range test (dmrt) at 5% level of probability (gomez and gomez, 1984). results and discussion yield contributing parameters number of pods plant-1 a significant variation was found in the total number of pods per plant due to different irrigation levels (figure 1). at harvest, the highest number of pods per plant (18.59) was found in irrigation at the vegetative and reproductive stage (i2) followed by the treatment of i1 (17.78). on the other hand, the lowest number of pods per plant (12.28) was also produced in no irrigation treatment. the number of pods per plant of lentil varied significantly due to different levels of boron application (figure 2). result showed that the highest number of pods per plant (18.49) was obtained from b3 (40% recommended dose as basal + rest 60% as a foliar spray at preflowering) at 65 days after sowing (das). likewise, the lowest number of pods per plant (13.47) was recorded from b0 (control) at harvest. the result showed that the maximum number of pods per plant (17.78) was recorded from i2b3 at harvest which was statistically similar to others except control. the lowest number of pods per plant (11.56) at harvest was obtained from i2b0 treatment (table 1). irrigation at higher frequencies may have decreased the plant water stress resulting higher partitioning of food materials into flower primordial which resulted the higher number pod setting in plants. this could be due to the greater role of foliar boron application in the production of indole acetic acid (iaa), which may have resulted in more pods per plant (taliee and sayadian, 2000). foliar application of boron and irrigation levels on lentil 131 i0 = no irrigation, i1= 25 das i2 = 25 & 40 das fig. 1. effect of irrigation on number of pods plant-1of lentil at different days after sowing (se= 0.837, 1.529, 0.2562 at 50, 65 das and at harvest respectively). b0 =control; b1 = 80% recommended dose as basal + rest 20% as a foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf fig. 2. effect of boron on number of pods plant-1 of lentil at different days after sowing (se = 0.599, 1.5679, 1.220 at 50, 65 das and at harvest respectively). 0 2 4 6 8 10 12 14 16 18 20 50 das 65 das at harvest n u m b e r o f p o d s p la n t⁻ ¹ days after sowing i₀ i₁ i₂ 0 2 4 6 8 10 12 14 16 18 20 b₀ b₁ b₂ b₃ n u m b er o f p o d s p la n t⁻ ¹ level of foliar boron 50 das 65 das at harvest 132 paul et al. table 1. interaction effect of irrigation and boron on number of pods plant-1 of lentil at different days after sowing treatment combinations number of pods plant-1 50 das 65 das at harvest i0b0 2.78 bc 13.45 a-c 13.72 a i0b1 2.89 bc 12.78 a-c 13.74 ab i0b2 6.55 a 11.67 a-c 14.52 ab i0b3 5.44 a-c 10.55 bc 12.14 b i1b0 5.33 a-c 15.22 a-c 13.15 ab i1b1 5.78 ab 15.89 a-c 14.67 ab i1b2 2.56 c 14.22 a-c 15.74 ab i1b3 4.11 a-c 20.67 a 16.55 ab i2bo 4.61 a-c 10.23 c 11.56 ab i2b1 4.22 a-c 11.78 a-c 15.26 ab i2b2 5.11 a-c 16.98 a-c 17.77 ab i2b3 5.33 a-c 19.22 ab 17.78 a se 1.039 2.715 2.113 cv (%) 12.97 13.46 14.05 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non-significant, i0 = no irrigation; i1= 25 das; i2 = 25 das and 40 das, b0 =control; b1= 80% recommended dose as basal + rest 20% as a foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf pod length significant variation was observed on pod length of lentil due to different levels of irrigation treatments (table 2). results revealed that the maximum pod length (1.31cm) was obtained from two irrigation i2 (at 25 days after sowing and 40 das) which was statistically similar to i1 (25 das). however, the lowest pod length (1.26 cm) was recorded from i0 (control).a substantial difference was also observed on seed length of lentil due to different levels of boron treatments (table 3). results showed that the maximum pod length (1.33cm) was obtained from b1 (80% as recommended dose as basal + rest 20% as a foliar spray at pre-flowering) was statistically similar to b2 (60% rd as basal + rest 40% as fs at pf), and b3(40% rd as basal + rest 60% as fs at pf). the lowest pod length (1.20 cm) was recorded from b0. pod length was significantly improved by the synergistic effect of different levels of irrigation and boron application (table 4). results showed that higher pod length (1.42 cm) was recorded from i2b3 combination which was statistically similar to i2b2, i2b1. however, the lowest pod length (1.23cm) was recorded from i0b0 combination which was statistically similar to i0b1, i0b2, i0b3, i1b0, i1b2 and i2b0 respectively. combinedly, boron application at two spilt and irrigation at optimum levels may have increased the cell division of flowers primordial resulted the vigorous development of pod in onward of growth stage. number of seeds pod-1 the number of seeds per pod of lentil, significant variation was observed due to different levels of irrigation treatments (table 2). results revealed that the highest number of seeds per pod (1.94) was obtained from i2 (25 days after sowing and 40 das) which was statistically similar to i1 (25 das). on the other hand, the lowest number of seeds per pod (1.61) was acquired from i0 (without irrigation). a similar result was founded by roy et al. (2016).the substantial influence was also found by different levels of boron application for the number of seeds per pod (table 3). result showed that maximum number of seeds per pod (2.00) was recorded from b3 which foliar application of boron and irrigation levels on lentil 133 was statistically identical to b1 (1.96). conversely, the lowest number of seeds per pod (1.74) was collected from b2 (60% rd as basal + rest 40% as fs at pf). the result of this study was similar to the pandey and gupta (2013).the number of seeds pod-1 was significantly influenced by the interaction effect of different levels of irrigation and boron application (table 4). results showed that the highest number of seed pod-1 (2.00) was recorded from i2b3 combination which was statistically similar to i2b1, i2b2, i2b1 and i1b1 treatment combination. likewise, the lowest number of seeds per pod (1.40) was recorded from i0b0 which was statistically similar to i0b2, i0b2, i1b0 i0b3, i1b0 and i2b0.islam et al. (2018) reported that agronomic bio-fortification through foliar boron application might have enhanced the seed setting that resulted in an increasing number of seeds per pod. 1000-seed weight the irrigation levels had a significant effect on 1000-seed weight where maximum 1000-seed weight (24.26 g) was recorded from two irrigations (i2) at 25 and 40 das which was significantly similar to i1 (25 das) respectively. the lowest 1000-seed weight (19.61 g) was obtained from i0 (control). hossain et al., (2013) was also found a significant increase in 1000seed weight with two irrigations; one at the pit-flowering stage and another at the fruiting stage. significant effect was also found by different levels of boron treatments for 1000-seed weight of lentil (table 3). table 2. effect of irrigation on yield contributing characters of lentil at harvest treatments yield contributing characters pod length (cm) number of seeds pod-1 1000-seed weight (g) i0 1.26 1.61 19.61 b i1 1.30 1.94 22.84 a i2 1.31 1.86 24.26 a se ns ns 0.725 cv (%) 8.52 12.14 11.29 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non significant, i0 = no irrigation; i1= 25 das; i2 = 25 das and 40 das table 3. effect of boron on yield contributing characters of lentil at harvest treatments yield contributing characters pod length (cm) number of seeds pod-1 1000-seed weight (g) b0 1.20 1.92 a 21.11b b1 1.33 1.96 ab 22.43 ab b2 1.29 1.74 b 22.87 a b3 1.25 2.00 a 22.53ab se ns 0.065 0.508 cv (%) 8.84 10.33 6.86 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non significant, b0=control; b1 = 80% recommended dose as basal + rest 20% as a foliar spray at preflowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf result revealed that the maximum 1000-seed weight (22.87 g) was recorded from b2 which was statistically similar to b1 (22.53 g) and b3 (22.53 g). similarly, the lowest 1000-seed weight (21.11 g) was obtained from b0 (control). maqbool et al. (2018) and vimalan et al. (2017) also 134 paul et al. noted similar results. weight of 1000-seed was significantly influenced by the interaction effect of different levels of irrigation and boron application (table 4). results showed that maximum 1000-seed weight (25.53 g) was recorded from i2b2 combination which was statistically identical to i1b1and similar to i2b3. accordingly, the lowest 1000-seed weight (17.69 g) was recorded from i0b0 combination which was statistically similar to i0b1 followed by i0b2, i0b3 and i1b0, respectively. gunasekera et al. (2006) noted that by increase in moisture stress intensity, 1000seed weight decreases. increased water use efficiency with increasing water stress has also been observed in lentils reflecting the lower soil evaporation component of water use without irrigation. the higher seed weight could be due to the higher mobilization of photosynthates to the developing seeds at higher accumulation boron (islam et al., 2018). table 4. interaction effect of irrigation and boron on yield contributing parameters of lentil at harvest treatment combinations yield contributing characters pod length (cm) number of seeds pod-1 1000-seed weight (g) i0b0 1.23 ab 1.40 17.69 e i0b1 1.28 ab 1.40 19.99 de i0b2 1.31 ab 1.67 21.05 cd i0b3 1.22 ab 1.57 20.98 cd i1b0 1.30 ab 1.70 23.01 a-d i1b1 1.22 ab 1.89 23.35 a-c i1b2 1.21 b 1.89 22.37 b-d i1b3 1.30 ab 2.00 23.29 a-c i2bo 1.36 ab 1.69 22.64 b-d i2b1 1.4 a 1.89 23.95 a-c i2b2 1.41 a 1.66 25.53 a i2b3 1.42 a 2.00 24.42 ab se 0.066 ns 0.814 cv (%) 8.84 10.33 6.3 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non-significant, i0 = no irrigation; i1= 25 das; i2 = 25 das and 40 das, b0 =control; b1= 80% recommended dose as basal + rest 20% as a foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf yield characters seed yield irrigation level exerted a significant result on lentil seed yield (table 5). the maximum seed yield (570.56 kg ha-1) of lentil was obtained from the treatment i2 (irrigation at 25 das and 40days after sowing) followed by the treatment i1 (irrigation at 25 days after sowing). the lowest seed yield (363.1 kg ha-1) was recorded from i0 (control). from the result, it was observed that seed yield increased gradually with the irrigation level. shortage of irrigation water greatly reduced the yield. a similar result was found by zhang et al. (2000). significant variation was also found by different levels of boron treatment (table 6). the highest seed yield (583.51 kg ha-1) was recorded from b3 followed by b2 and b1 while lowest seed yield (448.70 kg ha-1) from b0. vimalan et al. (2017) reported similar result with seed yield of green gram. the interaction of irrigation level and boron had a significant influence on seed yield (table 7). the maximum seed yield (638.23 kg ha-1) was recorded in from i2b3which was statistically different from i2b2, i2b1, i2b0, i1b3, i1b2, i1b1, i1b0, i0b3 combinations. likewise, the lowest amount of seed yield (210.67 kg ha-1) was recorded from i0b0. the increase in number of irrigation resulted in foliar application of boron and irrigation levels on lentil 135 significant increase in seed yield, which may be attributed from the higher number of pods per plant, number of seeds per pod and 1000-seed weight. increase in seed yield with increase in number of irrigations has been reported by panda et al. (2004). if micronutrients are applied in conjunction with macronutrients to favorably influence the plant vigor, morphology, and metabolic processes (valenciano et al., 2011). stover yield irrigation had a significant variation on stover yield of lentil (table 5). result showed that the highest stover yield (573.98 kg ha-1) was obtained from i2and the lowest stover yield (405.14 kg ha-1) was recorded from i0. the same result was found by paramjit and roy (2001). variation was also found by different levels of boron on stover yield of lentil (table 6). the result showed that the highest stover yield (598.81 kg ha-1) was recorded from b3and the lowest stover yield (496.31 kg ha-1) from b0. the combined effect of irrigation and boron showed a significant effect on stover yield of lentil (table 7). the highest stover yield (751.20 kg ha-1) was recorded from i2b3 combination while the lowest stover yield (252.27 kg ha-1) was recorded from i0b0 (control). application of two irrigations recorded significantly higher stover yield than one irrigation which in turn gave significantly higher stover yield than no irrigation in chickpea (pandey et al., 1984). this variation of results indicated that the increasing irrigation levels were more effective on soil moisture and favorable soil for more to more increase plant height as well as stover yield. the results showed that stover yield directly proportional to the application of irrigation water. it might be due to the morpho-physiological growth performance of plants that depends on optimum level of irrigation, which enhanced dry matter accumulation and finally increased overall yield performance. biological yield a significant effect was observed on biological yield of lentil in different levels of irrigation (table 5). the maximum biological yield (1167.2 kg ha-1) was recorded from i1 (25 days after sowing) which was statistically similar to i2 (25 days after sowing and 40 das). the lowest biological yield (768.3 kg ha-1) were obtained from i0 (no irrigation). roy et al. (2016) mentioned a similar result in chickpea. the biological yield was found significant in respect to boron (table 6). the result revealed that the highest biological yield (1182.4 kg ha-1) was recorded from b3 (40% recommended dose as basal + rest 60% as fs at pf) which was significantly different from b2 (60% rd as basal + rest 40% as fs at pf). likewise, the lowest biological yield (945.0 kg ha-1) was obtained from b0 (control).the interaction effect of irrigation and boron had a significant variation on biological yield (table 7). from the table, it was observed that higher biological yield (1389.4 kg ha-1) was recorded in the combination of i2b3 which was statistically incompatible with other treatments. the lowest biological yield (492.9 kg ha-1) was recorded from the combination of i0b0 (control). harvest index the harvest index was found significant in different levels of irrigation (table 5).the highest harvest index (49.85%) was recorded from i2 (irrigation at 25 das and 40das), which was statistically similar to i1 (25 das).there were no significant variations in case of harvest index due to different boron management except control treatment (table 6). among the treatments, b3gave the maximum harvest index (53.34%), which was followed by other treatments except b0 (control). the combined application of irrigation and boron had a significant variation on harvest index (table 7). the result showed that the maximum harvest index was calculated from i2b3 which was statistically different from other treatments. likewise, the lowest harvest index (43.24%) was recorded from the combination of i0b0 (control). 136 paul et al. table 5. effect of irrigation on yield and harvest index of lentil at harvest treatments seed yield (kg ha-1) stover yield (kg ha-1) biological yield (kg ha-1) harvest index (%) i0 363.10 b 405.14 b 768.24 b 47.26 i1 545.00a 552.22 a 1167.22 a 46.69 i2 570.56 a 573.98 ab 1144.54 a 49.85 se 2.057 5.467 5.782 ns cv (%) 14.46 35.48 19.51 16.02 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non significant, i0 = no irrigation; i1= 25 da; i2 = 25 das and 40 das table 6. effect of boron on yield and harvest index of lentil at harvest treatments seed yield (kg ha-1) stover yield (kg ha-1) biological yield (kg ha-1) harvest index (%) b0 448.70 b 496.31 945.01 b 47.48 b1 466.98 ab 486.90 953.88 b 48.95 b2 472.44 ab 553.02 1025.46ab 49.06 b3 583.51 a 598.89 1182.40 a 49.34 se 4.063 ns 7.266 ns cv (%) 24.73 28.44 21.23 16.2 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non-significant, b0 =control; b1= 80% recommended dose as basal + rest 20% as a foliar spray at preflowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf table 7. interaction effect of irrigation and boron on yield and harvest index of lentil at harvest treatment combinations yield and harvest index characters seed yield (kg ha-1) stover yield (kg ha-1) biological yield (kg ha-1) harvest index (%) i0b0 210.67 c 252.27 c 492.94 d 47.36 ab i0b1 268.77 bc 477.57 a-c 846.34 b-d 43.57 ab i0b2 271.03 bc 412.57 bc 783.60 cd 47.34 ab i0b3 372.20 ab 478.17 a-c 950.37bc 49.68 ab i1b0 357.23 ab 711.03 ab 1168.26 a-c 39.13 b i1b1 474.30 a 556.57 a-c 1130.87 a-c 50.78 b i1b2 508.37 ab 653.97 ab 1162.34 a-c 43.73 b i1b3 514.10 a 567.30 ab 1207.40ab 52.51 b i2bo 512.20 a 525.63 a-c 1173.83 a-c 53.85 b i2b1 457.87 ab 426.57 bc 884.44 b-d 51.77 b i2b2 537.93 ab 592.53 ab 1130.46 a-c 47.58 b i2b3 638.23 a 751.20 a 1389.43 a 45.93 a se 7.038 8.765 12.585 4.661 cv (%) 24.73 28.44 21.23 16.2 similar letter within the parenthesis do no differ significantly at 5% level of significance according to duncan’s multiple range test ns = non-significant, i0 = no irrigation; i1= 25 das; i2 = 25 das and 40 das, b0 =control; b1= 80% recommended dose as basal + rest 20% as a foliar spray at pre-flowering; b2 = 60% rd as basal + rest 40% as fs at pf; b3 = 40% rd as basal + rest 60% as fs at pf foliar application of boron and irrigation levels on lentil 137 conclusion it can be concluded that the irrigation and boron application as foliar spray significantly influenced the seed yield of lentil. seed yield and yield attributes of lentil were the best in the treatment i2b3 (two irrigations at 25 das and 40 das and boron at 40% rd as basal + rest 60% b as fs at pf). acknowledgement the authors avail the opportunity to express their sincere thanks and heartfelt gratitude to the government of the people’s republic of bangladesh through the ministry of science and technology (most) for providing financial support (nst fellowship) for conducting this research. references anantawiroon p., k.d. subedi and b. rerkasem. 1997. screening wheat for boron efficiency. in: bell r.w., and rerkasem b. (eds) boron in soils and plants. developments in plant and soil sciences, vol.76.springer, dordrecht. bbs. 2018. statistical yearbook of bangladesh. bangladesh bureau of statistics. ministry of planning, govt. of the people’s republic of bangladesh, dhaka. brown, p.h., n. bellaloui, h. hu, and a. dandekar. 1999. transgenically enhanced sorbitol synthesis facilitates phloem boron transport and increases tolerance of tobacco to boron deficiency. plant physiol. 119(1): 17-20. debaeke, p. and a. aboudrare. 2004. adaptation of crop management to water-limited environments. europ. j. agron. 21(4): 433-446. dordas, c., g.e. apostolides and o. goundra. 2007. boron application affects seed yield and seed quality of sugar beets. j. agric. sci. 145(4): 377-384. gomez, k. a. and a. a. gomez. 1984. statistical procedure for agricultural research. john willey and sons, new york. pp.97-411. gunasekera, c.p., l.d. martin, r.j. french, k.h.m. siddique and g. walton. 2006. genotype by environment interactions of indian mustard (brassica juncea l.) and canola (brassica napus l.) in mediterranean type environments: i. crop growth and seed yield. euro. j. agron. 25: 112. hossain, m., m. alam and m. ripon. 2013. effect of irrigation and sowing method on yield and yield attributes of mustard. rajshahi univ. j. life earth agric. sci. 41: 6570. islam, m., m. karim, m. oliver, m. hosain, t.a. urmi, m. hossain and m.m. haque. 2018.impacts of trace element addition on lentil (lens culinaris l.) agronomy.agron. 8(7): 100. maqbool, r., w. ali, m.a. nadeem and t. abbas. 2018. boron application in clayloam soil for improved growth, yield and protein contents of mungbean in water-stresses. sainsmalaysiana. 47(1):51-58. marschner, h. 1995. mineral nutrition of higher plants.2nd. edn. academic pres. panda, b.b., s.k. bandyopadhyay and y.s. shivay. 2004. effect of irrigation level, sowing dates and varieties on yield attributes, yield, consumptive water use and water-use efficiency of indian mustard (brassica juncea). indian j. agric. sci. 74(6): 339-342. pandey, n. and b. gupta. 2013. the impact of foliar boron sprays on reproductive biology and seed quality of black gram. j. trace. elem. med. biol. 27(1): 58-64. 138 paul et al. pandey, r.k., w.a.t. herrera, a.w. villegas and j.w. penletion. 1984. drought response of grain legumes under irrigation gradient. ii. plant growth agron. j. 76: 557-560. paramjit, v.p.s. and d.k. roy. 2001. effect of different levels of nitrogen and irrigation on nitrogen uptake and quality of malt barley var. alfa-93. res. crops.2(2): 120-122. pilbeam, d.j. and e.a. kirkby. 1983. the physiological-role of boron in plants. j. plant nutr.6(7): 563-582. quah, s. and n. jafar. 1994. effect of nitrogen fertilizer on seed protein of mungbean. applied biology beyond the year 2000.in: proc. 3rd symp. malaysian soc. appl. biol.pp.72-74. reddi, g.h. and t.y. reddi. 1995. irrigation of principal crops. in: efficient use of irrigation water.2nd ed, kalyani pub. new delhi pp.229-259. roy, i., p.k. biswas, m.h. ali, m.n. haque, m.s. islam and a.k.k. achakzai. 2016. effect of supplemental application of nitrogen, irrigation and hormone on the yield and yield components of chickpea. world j. agric. sci. 12(1): 70-77. singh, a., m. khan and s. arun. 2014. effect of boron and molybdenum application on seed yield of mungbean. asian j. biol. sci. 9(2): 169-172. subasinghe, s., g. dayatilake and r. senaratne. 2003. effect of b, co and mo on nodulation, growth and yield of cowpea (vignaunguiculata). trop. agric. res.6: 108-112. taliee, a. and k. sayadian. 2000. effect of supplemental irrigation and plant nutrient in chickpea (dry farming). j. agron. crop sci. 2: 12–19. valenciano, j.b., j.a. boto and v. marcelo. 2011. chickpea (cicerarietinum l.) response to zinc, boron and molybdenum application under field conditions. new zealand j. crop hort. sci. 39(4): 217-229. vimalan, b., p. gayathri, s. thiyageshwari and j. prabhaharan. 2017. effects of boron on the seed yield and protein content of green gram (vignamungo) var. co 8. life sci. int. res. j.4: 59. zhang, h., m. pala, t. oweis and h. harris. 2000. water use and water-use efficiency of chickpea and lentil in a mediterranean environment. aust. j. agric. res.51(2): 295-304. bangladesh agron. j. 2020, 23(2): 119-125 herbicide use strategy and its economy as a weed management option in wheat varieties m.g. mostafa, m.f. karim* and h.m.m.t. hossain department of agronomy, faculty of agriculture, sher-e-bangla agricultural university, dhaka, bangladesh *corresponding e-mail: pdmfkarim@yahoo.com (received: 13 november 2020, accepted: 27 november 2020) keywords: weed control, pre-emergence herbicide, economic management, wheat abstract weed pressure is an additional threat to high temperature stressed wheat crop for its optimum production. a field experiment was conducted at sher-e-bangla agricultural university, dhaka, bangladesh during rabi 2017-2018 to assess the response of wheat varieties to different weed managements and its economical viability. as such three varieties i.e. bari gom-28, bari gom-29, and bari gom-30 along with five weed managements viz. control (no weeding), two hand weeding at 20 and 40 das, panida 33ec (pendimethalin) @ 2000 ml ha -1 spray at 5 das as pre-emergence, affinity 50.75 wp (isoproturon) @ 1500 g ha -1 spray at 25 das as post-emergence and panida 33ec (pendimethalin) @ 2000 ml ha -1 at 5 das + affinity 50.75 wp (isoproturon) @ 1500 g ha 1 at 5 & 25 das were treatment variables tested under split plot design.cynodon dactylon, cyperus rotundus, echinochloa colona, eleusine indica, chenopodium album, alternanthera philoxeroides, brassica kaber, leliotropium indicum, vicia sativa,etc.werethe major weeds as determined based on their field intensity.results revealed that bari gom-30 out-yielded other varieties with the highest grain yield (3.01 t ha -1 ). pre-emergence application of panida 33ec at 5 das proved as suitable weed management compared to other methods. bari gom-30 in combination with panida 33ec @ 2000 ml ha -1 spray at 5 das as pre-emergence gave higher yield and yield attributes while bari gom-28 under no weeding check showed lower grain yield (2.09 t ha -1 ). economically maximum gross return (tk.75761.52ha -1 ),net income (tk.21775.92ha -1 ), and bcr (1.41) were associated with panida 33ec treatment when minimum values were obtained in the control plot (no weeding). so, the application of pre-emergence herbicide, panida 33ec might be economically viable weed management ensuring a higher yield in wheat cultivation. introduction wheat (triticum aestivum l.) is one of the world’s most commonly consumed cereal grains in general and staple food of about two billion people (36% of the world population) in particular. wheat provides about 55% carbohydrates and 20% food calories for the global population (breiman and graur, 1995). wheat grain contains 71% carbohydrate, 13% protein, 1.5% fat, 12% fibre, and some vitamins and minerals. it is also used for animal feed and a unique component in industrial use which is about 12%. as the second most important cereal crop in bangladesh, 13.16 lakh tons of grain is grown on 4.15 lakh ha land at an average annual production rate of 4.19% (bbs, 2019). but the area coverage and production may be reduced because of the rise in mean temperature by 0.66 °c since 1999 and by2.13°c in 2050 (poulton and rawson, 2011) and in recent past the infestation of wheat blast coupled with weeds abundance in wheat field. in general, wheat yield depends on varietal character, inputs, and agronomic management practices. the productivity of wheat is lower compared to other parts of south asia, which could be primarily forced to short growth duration due to higher average temperature than optimum temperature (24°c) and further aggravated with seasonal weeds infestation. weed competes with crop plants for water, nutrients, space, and solar radiation resulting in a reduction of yield by 20 to 50% (bhan and dixit, 1998). besides other crops weed is a major problem for maximizing higher yields of wheat mailto:pdmfkarim@yahoo.com 120 mostafa et al. and unchecked weed growth reduces crop yield up to 57% (singh et al., 1997). the shortage of labours for hand weeding makes the use of herbicides inevitable throughout the world (hossain, 2015). thus the application of herbicides is getting alternative attention from economic point of view (zhang, 2003: kauret al., 2018). considering the above facts, this experiment was undertaken to examine influence of pre and post-emergence herbicides either individual or double-action over the convention in the potential yields of some modern wheat varieties along with economic validation. materials and methods the field experiment was conducted at sher-e-bangla agricultural university, dhaka-1207 during rabi 2017-2018. the location of the experimental site is 90º37´ e longitude and 23º77´ n latitude. the soil belongs to the modhupur tract (aez no. 28). the experiment consisted of two factors as a) factor a: varieties (3) i.e. v1= bari gom-28, v2= bari gom-29, v3= bari gom-30 and b) factor b: weed managements (5) viz. w0 = no weeding (control), w1 = two hand weeding at 20 das and 40 das, w2 = panida 33ec (pendimethalin) @ 2000 ml ha -1 spray at 5 das (pre-emergence), w3 = afinity 50.75wp (isoproturon) @ 1500 g ha -1 spray at 25 das (post-emergence), w4 = panida 33ec (pendimethalin) @ 2000 ml ha -1 spray at 5 das + affinity 50.75wp (isoproturon) @ 1500 g ha -1 spray at 25 das. the experiment was laid out in a split-plot design with three replications where the variety was placed in the main plot and weed managements in subplot. fertilizers were applied following bari recommendations as urea, tsp, mop, and gypsum @ 220, 150, 50, and 120 kg ha -1 , respectively. the whole amount of all fertilizers and two-third amount urea was applied at the time of final land preparation and thoroughly incorporated with soil. rest urea was added at the crown root initiation (cri) stage (21 das). there were negligible infestations of insect-pests during the crop growth period. only mole cricket and cutworm attacked the crop during the early growing stage and controlled by spraying diazinon 60ec. data of yield and yield contributing parameters were collected at the final harvest. analysis of variance was done following mstat-c. the mean differences among the treatments were adjusted by least significant difference (lsd) at a 5% level of significance (gomez and gomez, 1984). results and discussion the spike length, spikelets spike -1 , grains spike -1 , and grain yield except 1000 grain weight were varied significantly due to variety (figs. 1, 2, and 3). it was observed that bari gom-30 (v3) produced longer spike (16.15cm) and at par with bari gom-29 (v2), a higher number of spikelets spike -1 (14.76) and similar with bari gom-29, maximum filled grain spike -1 (42.66), grain yield (3.01 t ha -1 ) and numerically maximum 1000-grain weight (50.84 g). variety bari gom-28 (v1) produced a lesser value of each parameter. sultana et al. (2012) had observed on spike length, spikelets spike -1 , grains spike -1 , and grain yield that variety differs with each parameter. chahal et al. (2003) reported a change in number of spikelets spike -1 and smeia et al. (2005) noted a varied number of grains spike -1 across the wheat varieties. on the other hand, hossain et al. (2010) noted that variety did not differ significantly in respect of 1000-grain weight. (a) (b) fig. 1. effect of variety on length of spike (lsd0.05=1.42) (a) and spikelets spike -1 (lsd0.05=1.34) (b) of wheat. herbicide use strategy and its economy as a weed management121 (a) (b) fig. 2. effect of variety on grains spike -1 (lsd0.05=2.02) (a) and 1000 grain weight of wheat (lsd0.05=ns) (b) of wheat. v1=bari gom-28, v2=bari gom-29, v3=bari gom-30 fig. 3. effect of variety on grain yield of wheat (lsd0.05=0.08). weed managements showed significant variation in spikelets spike -1 , grains spike -1 1000 grain weight, and grain yield except for spike length (figs. 4, 5, and 6).numerically longest spike length (15.77 cm) was recorded at w2 (panida 33ec) which also registered maximum spikelets spike -1 (14.68) and similar to other weed control methods, highest filled grain spike -1 (43.02) and was statistically similar with two hand weeding (w1) and panida 33ec + affinity 50.75wp (w4), greater 1000-grain weight (51.51 g) and at par with other weed management and highest grain yield (3.12 t ha -1 ) which was statistically similar with two hand weeding (w1). treatment no weed control (w0) was significantly inferior in all the above cases.hossain et al. (2010) recorded a gradual trend of increased length (7.25 and 12.12 cm) of the spike when they applied sencor 70wg @ 0.40 kg ha -1 at 60 das and 90 das, respectively. singh et al. (2004) opined similar results with pre-emergence pendimethalin @ 0.75 kg ha -1 along with one hand weeding or 2,4-d 0.5 kg ha -1 at 30 das that gave significantly higher spikes m -2 . pre-emergence herbicide, panida 33ec (pendimethalin) @ 2000 ml ha -1 spray at 5 das controlled weeds for greater production of yield components and grain yield as weed could not compete with wheat for nutrition, water, and sunlight. 122 mostafa et al. (a) (b) fig. 4. effect of different weed managements on the length of spike (lsd0.05=ns) (a) and spikelets spike -1 (lsd0.05=1.39) (b) of wheat. (a) (b) fig. 5. effect of different weed managements on the grains spike -1 (lsd0.05=4.71) (a) and 1000-grains weight (lsd 0.05=4.69) (b) of wheat. w0= no weeding, w1= two hand weeding, w2=panida 33ec, w3= afinity 50.75wp, w4=panida 33ec + affinity 50.75wp fig. 6. effect of different weed managements on grain yield of wheat (lsd0.05=0.27). the combined effect of variety and weed management seems to be influencing insignificant variations regarding spike length, spikelets spike -1 ,grains spike -1 ,1000-grain weight, and grain yield (table 1). the longest (16.70 cm) spike was measured at bari gom-30 with panida 33ec (v3w2) which was statistically similar with all other treatment combinations except v1w0, v1w3 and v1w4. the shortest 0 5 10 15 20 w0 w1 w2 w3 w4n o . o f sp ik el et s sp ik e -1 different weed control methods herbicide use strategy and its economy as a weed management123 spike (13.20 cm) was found in v1w0 (bari gom-28 and no hand weeding) and at par with v1w1, v1w2, v1w3, v1w4, v2w0, v2w1, v2w3, v2w4, and v3w0. number of spikelets spike -1 was counted highest (15.43) from v3w2 which was statistically similar with all other treatment combinations except v1w0 and v1w3. the lowest (12.40) number of spikelets spike -1 was obtained from v1w0 and similar with almost all other treatment combinations. filled grains spike -1 (47.38) was maximum, obtained from v3w2and followed by v2w1, v2w2, v3w1, v3w3, and v3w4. the lowest filled grains spike -1 (32.99) was found at bari gom-28 with no weeding (v1w0) which was statistically similar with all other treatment combinations except v2w1, v2w2, v3w1, and v3w4. maximum 1000 grain weight (53.57g) was showed by bari gom-30 with panida 33ec (v3w2) and similar with all treatment combinations except v1w0 and v1w3. the lowest 1000-grain weight (43.68 g) was noted from bari gom-28 with no weeding (v1w0) which was statistically similar with almost all other treatments. grain yield (3.52 t ha -1 ) was marked as highest in v3w2 which was at par with v3w1 and v2w2 when the lowest (2.09 t ha -1 ) from v1w0. application of pre-emergence herbicide, panida 33ec (pendimethalin) @ 2000 ml ha -1 at 5 das completely controlled weed population thus weed free wheat crop diverted maximum dry matter towards economic units of wheat followed by greater grain yield. this result is corroborated to sultana et al. (2012) who reported that the combined effect of variety and weeding methods had a significant effect on yield and yield contributing characters. table 1.combined effect of varieties and weed managements on the yield and yield contributing characters of wheat treatment combinations length of spike (cm) spikelets spike-1 (no.) grains spike-1 (no.) 1000-grain weight (g) grain yield (t ha-1) v1w0 13.20 d 12.40 c 32.99 d 43.68 c 2.09 g v1w1 14.31 a-d 13.80 a-c 37.57 b-d 48.49 a-c 2.57 d-f v1w2 14.60 a-d 13.94 a-c 39.06 b-d 49.84 a-c 2.69 d-f v1w3 13.31 cd 12.78 bc 35.03 cd 45.14 bc 2.27 fg v1w4 13.93 b-d 13.20 a-c 36.70 cd 46.97 a-c 2.46 d-g v2w0 14.33 a-d 13.22 a-c 35.76 cd 46.10 a-c 2.43 e-g v2w1 15.87 a-d 14.27 a-c 41.87 a-c 50.04 a-c 2.79 c-e v2w2 16.00 ab 14.67 a-c 42.63 a-c 51.12 a-c 3.16 a-c v2w3 14.63 a-d 13.61 a-c 36.68 cd 48.28 a-c 2.54 d-g v2w4 15.46 a-d 14.00 a-c 38.93 b-d 49.20 a-c 2.64 d-f v3w0 15.49 a-d 14.20 a-c 38.30 b-d 48.91 a-c 2.60 d-f v3w1 16.40 ab 15.07 ab 45.49 ab 51.97 ab 3.29 ab v3w2 16.70 a 15.43 a 47.38 a 53.57 a 3.52 a v3w3 15.93 a-c 14.41 a-c 39.57 a-d 49.51 a-c 2.70 c-f v3w4 16.23 ab 14.67 a-c 42.53 a-c 50.27 a-c 2.92 b-d lsd(0.05) 2.67 2.40 8.15 8.13 0.46 cv (%) 10.50 10.21 12.29 9.87 10.18 w0= no weeding; w1= two hand weeding: w2=panida 33ec: w3= afinity 50.75wp: w4=panida 33ec+affinity 50.75wp and v1=bari gom-28: v2=bari gom-29: v3=bari gom-30 as the labour cost is increasing sharply due to labour shortage in pick period so introducing the application of herbicide should be economically viable as per analysis. the analysis of weed managements revealed that cost of production was highest (tk. 58385.60 ha -1 ) from w1 (two hand weeding at 20 and 40 das) due to the higher rate of labour wedge and the lowest cost (tk. 53135.60 ha 1 ) was calculated from w0 (no weeding, control). the cost of production was varied from tk. 53885.60 ha -1 to tk. 54385.60 ha -1 due to the use of two different herbicides. the highest gross return (tk. 75761.52 ha -1 ) was obtained from the treatment w2 (panida 33ec, pendimethalin @ 2000 ml ha -1 spray at 5 das as pre-emergence) and the lowest gross return (tk. 57906.62 ha -1 ) was obtained from no weeding treatment (w0). the second-highest gross return (tk.70128.48 ha -1 ) was obtained from two hand weeding (w1) as the biological yield was higher after w2. on the other hand, the lowest gross return (tk. 57906.62 ha -1 ) was marked at w0 (control) attributed due to the minimum biological yield as plants were stressed under weed pressure caused by no weeding during their life span. as such the 124 mostafa et al. highest net income (tk. 21775.92 ha -1 ) was obtained from panida 33ec (w2) followed by the highest bcr (1.41) and no weeding treatment showed minimum values, tk. 4771.02 ha -1 and 1.09, respectively (table 2). rashid et al. (2012) reported that net income from herbicide application in rice was 116% higher than hand weeding owing to increased yield and lower cost. table 2. cost-benefit analysis of different weed management practices on wheat treatme nt cost of production (tk. ha-1) gross return (tk. ha-1) gross margin (tk. ha-1) bcr other cost of production weeding cost total cost grain straw total w0 53135.6 0 53135.60 53979.12 3924.0 57906.62 4771.02 1.09 w1 53135.6 5250 58385.60 65594.88 4533.6 70128.48 16142.88 1.20 w2 53135.6 850 53985.60 71061.12 4700.4 75761.52 21775.92 1.41 w3 53135.6 750 53885.60 57167.76 4092.0 61259.76 7374.16 1.14 w4 53135.6 1250 54385.60 60903.02 4357.2 65260.22 10874.62 1.20 w0= no weeding; w1= two hand weeding: w2=panida 33ec: w3= afinity 50.75wp: w4=panida 33ec+affinity 50.75wp and v1=bari gom-28: v2=bari gom-29: v3=bari gom-30 conclusion the use of herbicide is found suitable as alternative weed management where labour cost could be minimized. wheat var.bari gom-30 could be cultivated along with panida 33ec (pendimethalin) @ 2000 ml ha -1 spray (at 5 das) as a pre-emergence herbicide for its optimum economic yield harvest. references bbs (bangladesh bureau of statistics). 2019. yearbook of agricultural statistics-2017. ministry of planning. govt. of the people’s republic of bangladesh. p.39. bhan, v.m. and a. dixit. 1998. influence of isoproturon application for controlling phalaris minor in wheat. world weeds, 5(1&2): 53-56. breiman, a. and d. graur. 1995. wheat evolution. israel j. pl. sc. 43: 85-98. chahal, p.s., h.s. brar, and u.s. walia. 2003. management of phalaris minor in wheat through integrated approach. indian j. weed sci. 35(1&2): 1-5. gomez, a. and a. gomez. 1984. statistical procedure for agricultural research. 2nd edition, john willey and sons, new york. hossain, a., m.a.s. chowdhury, t. jahan, m.a.i. sarker and m.m. akhter. 2010. competitive ability of wheat cultivars against weeds. bangladesh j. weed sci. 1(1): 63-70. hossain, m.m. 2015. recent perspective of herbicide: review of demand and adoption in world agriculture. j. bangladesh agril. univ. 13(1): 19–30. kaur, e., r. sharma and n.d. singh. 2018. efficacy of ppre-eemergence and ppost-eemergence hherbicides on wweed control control and yield yield in wheatwheat. int. j. curr. microbiol. appl. sci. 7(2): 883-887. poulton, p.l. and h.m. rawson. 2011. physical constraints to cropping in southern bangladesh. in: rawson, h. m. sustainable intensification of rabi cropping in southern bangladesh using wheat and mungbean. aciar technical reports no. 78, p.256. rashid, m.h., m.m. alam and j.k. ladha. 2012. comparative efficacy of pretilachlor and hand weeding in managing weeds and improving the productivity and net income of wet-seeded rice in bangladesh. field crops res. 128: 17–26. singh, g., v.p. singh and m. singh. 2004. effect of carfentrazone-ethyl on non-grassy weeds and wheat yield. indian j. weed sci. 36(1&2): 19-20. herbicide use strategy and its economy as a weed management125 singh, r.k., d.k.singh, and r.p. singh. 1997. weed crop competition in wheat as affected by different weed species. indian j. weed sci. 29(3 & 4): 199. smeia, w., b.a. lone and s. ansar-ul-haq. 2005. weed management in late sown wheat using different herbicides. environ. ecol. 23(3): 546548. sultana, m.r., m.a. alim, m.b. hossain, s. karmaker and m.s. islam. 2012. effect of variety variety and weed weed management management practices practices on yield yield and yield yield attributes attributes of wheatwheat. j. environ. sci. nat. res. 5(2): 91-96. zhang, z.p. 2003. development of chemical weed control and integrated weed management in china. weed biol. manag. 3: 197– 203. bangladesh agron. j. 2022, 25(1): 1-6 effect of sowing date on fibre yield and yield attributes of advanced breeding line o-0412-9-4 and o043-7-9 of tossa jute (corchorus olitorius l.) j. ferdous, m.s. hossain, m.y. sarker, m.a. alim and m.m. islam1 agronomy division and 1planning, training and communication division, bangladesh jute research institute, dhaka, bangladesh corresponding e-mail: tanny.jannat92@gmail.com (received: 09 december 2021, accepted: 05 april 2022) keywords: tossa jute, breeding line, fibre yield and sowing date abstract the experiment was conducted at jute agriculture experimental station (jaes), manikganj and jute research sub station (jrss), jashore during 20192020 to determine the optimum sowing date of advanced breeding line o-0412-9-4, o-043-7-9 of tossa jute and bjri tossa pat 5 (o-795) used as control. the experiment was laid-out in factorial rcbd with three replications. crops were sown on four different dates viz., 30 march, 15 april, 30 april and 15 may as treatment variables. plants were harvested at 120 days after sowing. all crops were given normal cultural practices. results showed that advanced breeding line o-0412-9-4 and o-043-7-9 sown on 30 march to 10 april gave significantly higher fibre yield of 3.11 and 3.04 t ha-1, respectively) at manikganj and 3.13 and 3.11 t ha-1, respectively at and jashore. introduction jute (corchorus spp.) is a cash crop of bangladesh. jute is a common term used both for plant and the fibre obtained from the bark of the plants. jute is one of the mainstays of bangladesh economy. it plays an important role earning about 5-6% foreign exchange through exporting jute and jute goods. (islam et al., 2019). jute crop enriches the topsoil by adding organic matter through dropping leaves and leftover roots in the field (alam et al., 2019). the jute crop also greatly improves the soil fertility status by incorporating organic matter to the soil through decomposition of shaded leaves and plant residues and helps in breaking plough-pans through its long taproots. also, jute and jute goods have been recognized as being friendly to the environment. (haque et al., 2020). though national average yield is increased from 1.59 to 2.04 tons per hectare (bbs, 2015). but the present status of jute as a cash crop facing a problem for increasing preference to food crop due to population pressure. the quality status of jute seed at farm level is very poor and farmers are normally ignorant of seed quality and quality evaluating tests one of the most important problems for jute production in bangladesh is the unavailability of quality seed during proper time of sowing. only about 10 to 15% quality jute seeds are supplied by different national agencies, but the rest amount of quality seed is yet to be managed to supply (ferdous and islam, 2018). tossa jute is a high land crop grown in the summer season in bangladesh. it is the most important fibre crop as well as cash crop of the country (hossain et al., 2020). tossa (c. olitorious) produces more biomass in poor soil and has great potentiality as renewable (annual plant) raw materials for paper pulp production. there are so many attributes responsible for yield of jute fibre i.e. sowing time, plant population, plant height, base diameter etc. in traditional jute cultivation at farm level, the farmers are usually sow seeds in different times, but optimum sowing time plays very important rules for higher yield and quality fibre. to know appropriate sowing time is very essential to produce desirable amount of tossa jute as well as biomass. 2 ferdous et al. o-0412-9-4 and o-043-7-9 are promising important advanced breeding line of tossa jute. the experiment was therefore, undertaken to determine the appropriate date of sowing for advanced tossa breeding line o-0412-9-4 and o-043-7-9, at different agro-ecological zones of bangladesh for higher fibre yield. materials and methods the experiment was conducted at jute agriculture experimental station (jaes), manikganj, and jute research sub station (ss), jashore during 2019-2020. the experiment was laid out in factorial rcbd with three replications. unit plot size was 4.0m  2.5m. advanced breeding line of tossa o-0412-9-4, o-043-7-9 and variety bjri tossa pat 5 (o-795) was used as control. crops were sown on four different dates viz., 30 march, 15 april, 30 april and 15 may as treatment variables. seeds were sown in line of 30 cm apart. other cultural and intercultural practices were followed as per bjri recommendation. plants were harvested at 120 days after sowing. location wise average data of fibre yield and quality attributing characters were analyzed with the help of computer statistical package (statistix 10). the mean differences among the treatments were adjusted as per least significant difference (lsd) at 0.05 level (gomez and gomez, 1984). results and discussion results revealed that plant population and plant height differ significantly due to variety irrespective of sowing date at jaes manikganj. at the same location, fibre yield and stick yield were not differed significantly due to variety irrespective of sowing date (table 1). advanced breeding line line o-04129-4 and o-043-7-9 were gave numerically higher fibre yield (2.92 t ha-1) and (2.95 t ha-1) over control variety o-795 (2.86 t ha-1) at manikganj. at jashore, fiber yield and stick yield both were significantly higher than advanced breeding line o-0412-9-4 and o-043-7-9 (2.95 t ha-1) and (3.07 t ha-1) than control variety (2.56 t ha-1). hossain et al. (2015), islam and rahman (2008) were also reported the similar observations. table 1. effect of variety irrespective of date of sowing on fibre yield and yield components of tossa jute at different locations location treatments pp (m-2) ph (m) bd (mm) fy (t ha-1) sy (t ha-1) manikganj o-0412 31.46 2.99 15.27 2.92 5.80 o-043 32.82 2.90 15.11 2.95 5.84 o-795 32.54 2.81 14.82 2.86 5.83 lsd(0.05) 0.90 0.14 ns ns ns cv (%) 3.28 5.56 4.06 5.46 5.63 jashore o-0412 32.36 2.90 15.56 2.95 6.34 o-043 31.76 2.88 16.06 3.07 6.55 o-795 30.40 2.90 15.68 2.56 6.07 lsd(0.05) 0.81 ns 0.77 0.10 0.22 cv (%) 3.04 7.87 5.83 3.95 4.30 ns = not-significant, pp = plant population, ph = plant height, bd = base diameter, fy = fibre yield, sy = stick yield. results showed that yield and yield contributing characters like plant population, base diameter, plant height and fibre yield were significantly affected due to sowing date irrespective of variety at manikganj (table 2). crop sown on 30 march gave the highest fibre and stick yields (3.13 and 6.44 t ha-1, respectively). plant height (3.06m) and base diameter (15.74 mm) were also found the highest at the same date. the crop sown on 20 march recorded the lowest fibre and stick yields (2.70 and 5.40 t ha-1, respectively) at manikganj. all the yield and yield contributing characters like plant population, base diameter, fibre yield and stick yield were significantly affected but only plant height was affected significantly due to sowing date irrespective of variety at jashore (table 2). crops sown on 10 april gave the highest fibre and stick yield (3.10 t ha-1 and 6.45 t ha-1, respectively) at jashore. among the effect of sowing date on fibre yield and yield attributes of tossa jute 3 sowing dates, plant height (2.97 m) and base diameter (15.95 mm) were also found the highest crop sown 10 april. the lowest fibre and stick yield (2.91 and 6.00 t ha-1, respectively) were obtained from the crop sown on 20 march. similar observations were reported by islam and rahman (2008) and islam and alam (2012). irrespective of locations plant height of the advanced breeding line o-0412-94 and o-043-7-9were 2.95 m and 2.89 m which was 3.14 and 1.04% higher than that of bjri tossa pat-5 (2.86 m) (figure 1). likewise, base diameter of the advanced breeding line o-0412-9-4 and o043-7-9 were 15.42 mm and 15.59 mm which was 1.11 and 2.22% higher than that of bjri tossa pat5 (15.25 mm) (figure 2). similarly, advanced breeding line o-0412-9-4 and o-043-7-9 were produced 2.94 and 3.07 t ha-1 fibre, respectively which was also 8.48 and 13.28% higher than that of bjri tossa pat-5 (2.71 t ha-1) (figure 4). at the same time, advanced breeding line o-0412-9-4 and o-043-7-9 were produced 6.07 t ha-1 and 6.20 t ha-1 stick, respectively which was also 2.02 and 2.24% higher than that of bjri tossa pat-5 (5.95 t ha-1) (figure 3). similar observations were reported by ferdous and islam (2018). fig. 1. plant height as affected by advance line/variety of jute fig. 2. base diameter as affected by advance line/variety of jute fig. 3. fibre yield as affected by advance line/variety of jute fig. 4. stick yield as affected by advance line/variety of jute it was observed that yield and yield contributing characters like plant population, base diameter and plant height, fibre yield and stick yield were affected significantly due to interaction of variety and sowing date at manikganj (table 3). the advanced breeding line o-0412-9-4 sown on 30 march gave the highest fibre and stick yield (3.11 t ha-1 and 6.50 t ha-1, respectively at manikganj. the advanced breeding line o-043-7-9 sown on 10 april gave the highest fibre and stick yield (3.14 t ha-1 and 6.37 t ha-1, respectively at manikganj. the lowest fibre yields (2.74 t ha-1and 2.77 t ha-1, respectively) were recorded from the breeding line o-0412-9-4 and o-043-7-9 sown on 20 april at manikganj. hossain et al. (2015); ferdous and islam (2018); islam and rahman (2008) and islam and alam (2012) were reported the similar results. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 o-0412 o-043 o-795 p la n t h e ig h t (m ) advance line/variety 0.00 5.00 10.00 15.00 20.00 o-0412 o-043 o-795 b a se d ia m e te r (m m ) advance line/variety 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 o-0412 o-043 o-795 s ti ck y ie ld ( t h a -1 ) advance line/variety 0.00 1.00 2.00 3.00 4.00 o-0412 o-043 o-795 f ib re y ie ld ( t h a -1 ) advance line/variety 4 ferdous et al. table 2. effect of date of sowing irrespective of variety on fibre yield and yield components of tossa jute at different locations location treatments pp (m-2) ph (m) bd (mm) fy (t ha-1) sy (t ha-1) manikganj 20 march 31.55 2.80 14.74 2.70 5.40 30 march 33.35 3.06 15.74 3.13 6.44 10 april 32.85 2.99 15.43 3.03 6.24 20 april 31.35 2.74 14.36 2.71 5.49 lsd(0.05) 1.03 0.16 0.60 0.15 0.32 cv (%) 3.28 5.56 4.06 5.46 5.63 jashore 20 march 29.34 2.85 15.04 2.91 6.00 30 march 34.45 2.96 15.95 3.01 6.22 10 april 34.16 2.97 16.05 3.10 6.45 20 april 28.07 2.79 15.10 2.96 6.08 lsd(0.05) 0.93 ns 0.89 0.12 0.26 cv (%) 3.04 7.87 5.83 3.95 4.30 ns = not-significant, pp = plant population, ph = plant height, bd = base diameter, fy = fibre yield, sy = stick yield. table 3. interaction effect of variety and date of sowing on fibre yield and yield components of tossa jute at manikganj treatments pp (m-2) ph (m) bd (mm) fy (t ha-1) sy (t ha-1) v1 x s1 29.75 2.89 15.23 2.78 5.38 v1 x s2 33.14 3.13 15.94 3.11 6.50 v1 x s3 31.85 3.11 15.41 3.07 6.20 v1 x s4 31.11 2.84 14.50 2.74 5.24 v2 x s1 32.14 2.76 14.27 2.84 5.86 v2 x s2 32.31 3.08 14.83 2.93 6.31 v2 x s3 33.70 3.03 16.00 3.14 6.37 v2 x s4 33.40 2.74 14.17 2.77 5.46 v3 x s1 32.90 2.75 14.73 2.49 4.95 v3 x s2 34.70 2.78 16.46 2.65 6.45 v3 x s3 33.03 3.05 14.87 3.08 6.22 v3 x s4 29.53 2.64 14.40 2.62 5.76 lsd(0.05) 1.79 0.73 1.04 0.27 0.56 cv (%) 3.28 5.56 4.06 5.46 5.63 ns = not-significant; v1= o-0412, v2= o-043, v3= o-795; s1= 20 march, s2= 30, march, s3= 10 april, s4= 20 april; pp = plant population, ph = plant height, bd = base diameter, fy = fibre yield, sy = stick yield. it was observed that yield and yield contributing characters like plant population and plant height, base diameter, fibre yield and stick yield were affected significantly due to interaction of variety and sowing date at jashore (table 4). the advanced breeding line o-0412-9-4 sown on 30 march gave the highest fibre and stick yields (3.13 t ha-1 and 6.35 t ha-1, respectively) at jashore. the advanced breeding line o-043-7-9 sown on 10 april gave the highest fibre and stick yields (3.18 t ha-1 and 6.41 t ha-1, respectively) at jashore. the lowest fibre yields (2.75 t ha-1 and 3.03 t ha-1, respectively) were recorded from the breeding line o-0412-9-4 and o-043-7-9 sown on 20 march at jashore. the similar observations were reported by hossain et al. (2015) and islam and alam (2012). table 4. interaction effect of variety and date of sowing on fibre yield and yield components of tossa jute at jashore treatments pp (m-2) ph (m) bd (mm) fy (t ha-1) sy (t ha-1) effect of sowing date on fibre yield and yield attributes of tossa jute 5 v1 x s1 30.21 2.89 15.21 2.75 6.57 v1 x s2 36.48 3.17 17.29 3.13 6.35 v1 x s3 34.56 2.92 16.05 3.00 6.22 v1 x s4 28.18 2.61 15.66 2.93 6.21 v2 x s1 32.15 2.83 14.37 3.03 5.82 v2 x s2 32.68 2.84 14.41 3.03 6.34 v2 x s3 33.44 2.96 15.48 3.18 6.41 v2 x s4 28.76 2.89 15.19 3.10 6.04 v3 x s1 25.65 2.83 15.71 2.94 5.61 v3 x s2 33.32 2.88 16.13 2.85 6.00 v3 x s3 35.33 3.04 16.62 3.01 6.80 v3 x s4 27.28 2.86 14.27 2.85 5.88 lsd(0.05) 1.62 0.39 1.53 0.22 0.45 cv (%) 3.04 7.87 5.83 3.95 4.30 ns = not-significant; v1= o-0412, v2= o-043, v3= o-795; s1= 20 march, s2= 30 march, s3= 10 april, s4= 20 april; pp = plant population, ph = plant height, bd = base diameter, fy = fibre yield, sy = stick yield. conclusion from the study, it was found that the advanced tossa breeding line o-0412-9-4 and o-043-7-9 gave higher yield and yield contributing characters like plant population and plant height, base diameter, fibre yield and stick yield when sown at on 30 march to 10 april at manikganj and jashore. references alam m.a., j. ferdous, m.r. debnath, m.s.hossain and m.m. islam. 2019. reduction of production cost of jute (bjri tossa pat 5) as influenced by urea top dressing dose and period. res. j. food nutr. 3(3): 1-5. bbs. 2015. yearbook of agricultural statistics of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. ferdous, j. and m.m. islam. 2018. off season seed yields of bjri tossa pat-7 and bjri tossa pat-5 as affected by sowing dates and locations. j. expt. biosci. 9(2): 55-63. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. second edn. john wiley and sons inc., new york. pp.304-307. haque, s.m.a., m. kamrujjaman, m.s. hossain, j. ferdous and m.t. rahman. 2020. disease incidence, seed quality and yield of jute variety cvl-1 affected by seeds stored in different types of containers. int. j. sustain. agril. technol. 16(5): 08-13. hossain, m.s., j. ferdous, m. kamrujjaman, m.a. alim and m.m. islam. 2020. fibre yield, yield attributes and economics of tossajute (corchorus olitorius l.) as affected by different weedicides. int. j. sustain. agril. technol. 16(5): 14-19. hossain, m.s., m.m. islam, i. ahmed m.s. rahman and m.l. rahman. 2015. effect of sowing dates on fibre yield and yield attributes of white jute breeding line bjc-5003 at different locations of bangladesh. int. j. sustain. agril. technol. 11(8): 01-06. islam, m.m. and a.t.m.m. alam. 2012. agronomic research and advancement in jute crop in bangladesh, (sub-theme paper). souvenir, 11th conference on advances in agronomic research under changing environment in bangladesh. held on october 6, 2012 at bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh. p.101. islam, m.m. and m. rahman. 2008. hand book on agricultural technologies of jute, kenaf and mesta crops. bangladesh jute research institute, manikmia avenue, dhaka-1207, bangladesh. p.92. 6 ferdous et al. islam, m.m., j. ferdous and m.m. hoque. 2019. assessment of o-9897 seedling growth and dry weight parameters under greenhouse and field conditions as influenced by seed source and seedling age. am. j. plant biol. 4(3): 28-33. jute (corchorus spp.) is a cash crop of bangladesh. jute is a common term used both for plant and the fibre obtained from the bark of the plants. jute is one of the mainstays of bangladesh economy. it plays an important role earning about 5-6% foreign... bangladesh agron. j. 2021, 24(2): 99-107 growth, grain development and yield performance of boro rice varieties under water stress condition c.k. apu1, p.k. biswas2*, t.s. roy2, s. shome2 and a. barman3 1department of agricultural extension (dae), nasirnagar, brahmanbaria, bangladesh 2department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh 3soil science division, bangladesh agricultural research institute, gazipur, bangladesh *corresponding email:parimalbiswas@hotmail.com (received: 27 october 2021, accepted: 08 november 2021) keywords: irrigated rice; moisture stress; water deficit; water management; yield abstract a field experiment was conducted at the agronomy field, sher-e-bangla agricultural university, dhaka to evaluate the effect of water stress at reproductive stage on growth, grain development and yield of boro rice. the experiment consisted of two factors: factor a: water stress viz. no water stress (w1) and water stress (w2) and factor b: variety viz. brri dhan28 (v1), brri dhan29 (v2), brri dhan50 (v3), binadhan-10 (v4), brri hybriddhan3 (v5), aloron (v6). in no water stress, irrigation water was maintained strictly from transplanting time to harvesting time while in water stress condition; supply of irrigation was stopped just after flowering upto harvest. results showed that growth, grain development and yield of boro rice were significantly affected by water stressed condition. all the tested varieties performed better under no water stress condition compared to water stress condition. about 7% panicle weight was decreased due to water stress condition at reproductive stage. grain development of brri dhan29 was least affected by water stress while the most affected variety was binadhan-10. water deficit at reproductive stage reduced about 15-22% grain yield of tested varieties. aloron was the least affected variety due to water stress while brri dhan50 was the most affected variety. the variety aloron provided equal yield (7.31 t ha-1) under stress condition as given by brri dhan29 under no water stress condition. so, aloron may be a better option to cultivate in the region where irrigation water is scarce or costly. introduction rice which is the driving force of bangladesh agriculture occupies about two-thirds of the cultivated land area and constitutes 90% of the food grain production in bangladesh (bbs, 2020). boro (january may) is the single largest crop grown in bangladesh which accounts more than 50% of total rice production (bbs, 2020). boro rice is generally cultivated under irrigated condition when rainfall is very scanty. irrigated rice cultivation is the most productive and plays a vital role in fulfilling global food demand. but one estimate shows that2000–5000 l of water is required to produce 1 kg of rice (caine et al. 2019). but accelerated urbanization and industrialization result in decreasing freshwater resources for rice production. therefore, time demands the production of “more rice with less water” for global food security (maneepitak et al., 2019). water stress is one of the most restrictive factors for growing rice (halder et al., 2018). keller (2005) reported that water flow through the soil-root-shoot pathway assists nutrient uptake by plant roots and leaf transpiration generates the tension necessary for the roots to absorb this essential solution so in a dry soil, uptake of water and nutrients becomes progressively more difficult for any crop. moisture stress hampers photosynthesis in plants by closing stomata and destructing the chlorophyll contents and photosynthetic apparatus(waraich et al., 2011).disturbed photosynthesis adversely affects the tiller number, leaf area, dry matter production, mailto:parimalbiswas@hotmail.com 100 aup et al. filled grains per panicle, 1000-grain weight and grain yield (sabetfar et al., 2013). drought stress at vegetative phase of rice has minimal effect on subsequent growth and grain yield whereas drought during reproductive stage causes about 30% yield reduction (fofana et al., 2010).this might be due to low dry matter accumulation, delayed an thesis, reduction of the number of spikelets per panicle and decrease in numbers of filled grains (halder and burrage, 2003). actually water stress during reproductive stage may reduce grain mass by 20%, no. of spikelet up to 60%, filled grains up to 40% which contribute as a whole to reduction in yield. farmers use groundwater for boro rice cultivation as it is available in comparison with any other facilities. but, excessive and improper use of groundwater threatened soil horizon, environment as well as groundwater availability. exploring the ways to reduce water use for rice production is therefore of great strategic value for sustainable crop production for the world facing water scarcity (molden et al., 2010).considering the above fact , a detailed study was undertaken to explore the extent of water stress at reproductive stage affects growth and yield of rice and to find out suitable varieties providing high yield under water stress condition and saving the cost of irrigation water in boro rice production. materials and methods the experiment was conducted at sher-e-bangla agricultural university (2377n latitude and 9033e longitude) which belongs to the agro-ecological zone of the modhupur tract, aez-28 (anonymous, 1988). split plot design with three replications was followed to implement the experiment where water stress was put in the mainplots and variety in the sub-plots. there were two water stress conditions (w1: no water stress and w2: water stress) and six varieties v1: brri dhan28,v2: brri dhan29, v3: brri dhan50,v4: binadhan-10,v5: brri hybriddhan3 and v6: aloron. water stress means absence of irrigation water from reproductive stage to harvesting stage where no water stage means no scarcity of irrigation water during rice cultivation. before reproductive stage there is no discrimination of irrigation water among the plots. unit plot of 4 m × 2 m was made with 0.75 m distance between plot to plot.thirtydays old seedlings were transplanted in the main field. the experimental area was fertilized with 120, 80, 80, 20 and 5 kg ha-1 of n, p2o5, k2o, s and zn as per recommended method (frg, 2012). crop management was practiced according to necessity. plant height, number of tillers hiil-1 and number of leaves hiil-1were calculated from randomly pre-selected 5 hills plot-1. dry matter was recorded from the mean oven dry weight of plants from 2 hills per plot. filled grains panicle-1 and unfilled grains panicle-1 were counted from the average number of grains from ten panicles.1000-grain weight was measured at 12% moisture content.grain yield and straw yield were determined from the central 4 m2 area of each plot and expressed as t ha-1. biological yield was calculated by summing up the grain and straw yield. harvest index refers to the ratio of economic yield to biological yield and was computed with following formula (gardner et al., 1985). harvest index (%) = all the data collected on different parameters were statistically analyzed following the analysis of variance (anova) technique using statistix 10 computer package program and the mean differences were calculated using least significant difference (lsd) test at 5 % level of significance. results and discussion effect of water stress on crop growth characters crop growth parameters viz. plant height, number of tillers hill-1 and number of leaves hill-1showed significant variation when water stress was imposed at reproductive stage (table 1). plants under no water stress condition were found to be a bit taller with higher number of tillers and leaves than the plants under water stress condition. number of tillers and leaves hill-1 were reduced by about 8% and 12%, respectively due to water stress condition. about 12% higher stem dry weight was recorded for 100 yield biological yieldgrain  growth, grain development and yield performance of boro rice 101 no water stress condition than water stress condition. on the other hand, leaf dry weight and root dry weight were not influenced by water stress condition. sokoto and muhammad (2014)found water stress at flowering and grain filling stage decreased plant height. plant cannot uptake sufficient nutrients from soil due to water scarcity which consequently caused plant growth retardation (mannan et al., 2012). mostajeran and rahimi-eichi (2009) documented decreased tiller number per hill due to decreased soil moisture level. inability to produce dry matter due to inhibited photosynthesis by moisture stress might be responsible for lower tiller production. dearth of water required for food production and cell division might be another reason (zubaer et al., 2007). effect of variety on crop growth characters varietal differences had significant impact on all growth parameters (table 1). at harvest, tallest plant (106.98 cm) was recorded from binadhan-10 and shortest plant (85.03 cm) was obtained from brri dhan50. maximum number of tillers (14.88) and leaves (48.64) were observed in brri dhan50 while minimum tillers (10.50) and leaves (23.0) were recorded from aloron. brri dhan50 provided lowest leaf dry weight while binadhan-10 produced lowest stem and root dry weight at harvest. the variety brridhan29 gave highest stem and root dry weight which was significantly different from other varieties. the variation in plant height among the different varieties might be due to genetic makeup of different varieties (murshida et al., 2017). table 1. effect of water stress and variety on growth parameters of boro rice at harvest treatments plant height (cm) number of tillers hill 1 number of leaves hill-1 leaf dry weight (g hill-1) stem dry weight (g hill-1) root dry weight (g hill-1) water stress w1 98.35 a 12.48 a 35.05 a 16.77 31.31 a 9.39 w2 93.68 b 11.53 b 30.79 b 15.05 27.57 b 8.23 lsd(0.05) 4.27 0.60 2.36 ns 2.29 ns cv (%) 3.09 23.82 12.07 13.76 5.41 21.02 variety v1 94.75 b 12.35 ab 42.81 b 19.04 a 33.24 ab 9.67 ab v2 95.46 b 12.47 ab 25.16 d 19.51 a 35.89 a 12.04 a v3 85.03 c 14.87 a 48.64 a 9.45 c 26.40 c 7.21 bc v4 106.98 a 10.93 b 32.93 c 16.06 a 26.04 c 6.27 c v5 98.29 b 10.90 b 25.00 d 14.30 b 27.06 c 8.03 bc v6 95.56 b 10.50 b 23.00 d 17.09 ab 27.99 bc 9.66 ab lsd(0.05) 3.54 2.74 5.80 4.18 5.79 2.51 cv (%) 3.06 17.92 14.63 21.81 16.34 23.63 w1no water stress, w2water stress and v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5brri hybrid dhan3, v6aloron. interaction effect of water stress and varietyon crop growth characters interaction effect of water stress and variety had significant influence on all crop growth parameters (table 2). all the tested varieties performed better under no water stress condition. when there was no water stress throughout the crop duration, tallest plant (110.37 cm)was recorded from binadhan-10 and maximum number of tillers and leaves were recorded from brri dhan50. at harvest, the variety brri dhan29 provided maximum leaf, root and stem dry weight. when water supply was stopped at reproductive stage, growth and development of all the tested varieties were hampered considerably. tiller and leaf production of brri dhan50 was least affected by water stress. brri dhan29 and aloron accumulated more dry matter in stem, leaves and root at harvest under water stress condition compared to other varieties. chowdhury et al. (2004) observed that plant height decreased with the decrease in soil moisture levels and elucidated inhibition of cell division and cell enlargement due to water stress as the possible reason. 102 aup et al. table 2. interaction effect of water stress and variety on growth parameters of boro rice at harvest treatments plant height (cm) number of tillers hill -1 number of leaves hill-1 dry leaf weight (g hill-1) dry stem weight (g hill-1) dry root weight (g hill-1) w1v1 97.25 cd 12.60 abc 46.13ab 19.74 a 35.89 ab 10.12 ab w1v2 97.41 cd 13.80 ab 28.07 def 20.96 a 39.93 a 13.34 a w1v3 86.68 ef 15.61 a 51.75 a 11.49 bc 27.86 bcd 9.13 bc w1v4 110.37 a 11.07 bc 34.20 cd 16.27 ab 25.35 cd 5.98 cd w1v5 101.17 bc 11.00 bc 25.47ef 16.91 ab 31.14 bc 8.52 bcd w1v6 97.21 cd 10.80 bc 24.73 ef 15.24 ab 27.67 cd 9.26 bc w2v1 92.25 de 12.10 abc 39.50 bc 18.35 a 30.58 bcd 9.22 bc w2v2 93.51 d 11.13 bc 22.27 f 18.06 a 31.86 bc 10.74 ab w2v3 83.39 f 14.13 ab 45.53 ab 7.41 c 24.93 cd 5.28 d w2v4 103.60 b 10.80 bc 31.67 cde 15.85 ab 26.74 cd 6.56 cd w2v5 95.41 cd 10.80 bc 24.53 ef 11.69 bc 22.97 d 7.53 bcd w2v6 93.91 d 10.20 c 21.27 f 18.95 a 28.32 bcd 10.05 ab lsd(0.05) 5.009 3.790 8.20 5.910 8.190 3.490 cv (%) 3.06 17.92 14.63 21.81 16.34 23.63 w1no water stress, w2water stress and v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5brri hybrid dhan3, v6aloron. effect of water stress on yield and yield contributing characters filled grainspanicle-1, 1000-grains weight and harvest index were not significantly influenced by different water stress condition while water stress had significant effect on unfilled grainspanicle-1, grain yield, straw yield and biological yield (table 3).all the yield and yield contributing characters achieved maximum value under no water stress condition. water stress at reproductive stages caused about 14% yield reduction compared to no water stress condition. mannan et al. (2012)reported lower number of filled grains per panicle and grain weight due to water stress at reproductive stage. inactivation of pollen grain due to dryness, hampered pollen tube development and disturbed assimilates production and distribution might be the causes (fofana et al., 2010).actually moisture stress obstructs photosynthesis and limits the supply of photosynthates to developing grains which eventually reduces grain yield. effect of variety on yield and yield contributing characters varietal performance had significant impact on yield and yield contributing characters (table 3). the maximum number of filled grains panicle-1(133.28)was obtained from brri dhan29 which was statistically at par with brri dhan28 and brri hybrid dhan3. the lowest number of filled grains panicle-1 (98.88) was recorded from aloron. maximum 1000-grain weight (26.55 g) was obtained from brri hybrid dhan3 and minimum (21.03 g) from brri dhan28. aloron provided maximum grain yield which was 12% and 18% higher than brri hybrid dhan3 and brri dhan29. lowest yielder brri dhan50 and brri dhan28 gave about 50% lower yield than aloron. aloron also had the highest straw yield and biological yield. maximum harvest index (49.64%) was recorded from brri dhan29 which was statistically similar with other varieties except brri dhan50 and brri hybrid dhan3. mannan et al. (2012) also documented significant variations in case of yield and yield contributing attributes due to difference in genetic makeup of varieties. table 3. effect of water stress and variety on yield and yield contributing characters of boro rice treat ments filled grains panicle-1 unfilled grains panicle-1 1000grain weight grain yield (t ha-1) straw yield (t ha-1) biolo gical yield (t ha-1) harvest index (%) growth, grain development and yield performance of boro rice 103 water stress w1 117.8 14.23 22.31 6.86 a 7.4 a 14.26 a 48.1 w2 106.6 20.04 22.26 5.75 b 6.47 b 12.22 b 47 lsd(0.05) ns 1.87 ns 0.48 0.79 1.24 ns cv (%) 8.14 7.59 0.54 5.31 7.91 1.95 1.95 variety v1 121.25 a 21.27 a 21.03 c 5.14 d 5.70 d 10.84 d 47.35 ab v2 133.28 a 20.70 a 18.37 d 6.74 b 6.84 b 13.57 c 49.64 a v3 102.15 bc 21.42 a 18.37 d 5.05 d 5.91 d 10.97 d 46.17 b v4 100.82 bc 10.48 b 25.19 b 5.85 c 6.55 bc 12.40 c 47.20 ab v5 117.17 ab 11.95 b 26.55 a 7.08 b 8.09 a 15.17 b 46.68 b v6 98.88 c 17.00 ab 25.40 b 7.98 a 8.53 a 16.51 a 48.25 ab lsd(0.05) 16.4 7.78 0.66 0.63 0.75 1.18 2.87 cv (%) 12.13 25.01 2.45 8.31 8.94 7.42 5.00 w1no water stress, w2water stress and v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5brri hybrid dhan3, v6aloron. interaction effect of water stress and varietyon yield and yield contributing characters the interaction between water stress and variety significantly influenced yield and yield contributing characters (table 4). all the tested varieties performed better under no water stress condition than water stress condition from reproductive stage to harvest. brri dhan29 gave the maximum filled grainspanicle-1both under no water stress condition (145.43) and water stress condition(121.13). number of unfilled grains was found minimum in binadhan-10 under both the situation when plants faced no water stress and water stress at reproductive stage. grain yield was considerably reduced (1522%) due to water stress condition in case of all the varieties. aloron provided maximum grain yield in both the cases of no water stress and water stress but water stress reduced about 15% yield of that variety. however, grain yield of aloron was the least affected due to water stress while brri dhan50 (22% yield reduction) was the most affected variety by water stress. better performance was also recorded from aloron in case of straw yield and biological yield. harvest index of varieties was not significantly influenced by water stress except brri dhan50. sarvestani et al. (2008) documented that water stress at reproductive stage reduced about 50% grain yield in comparison to no water stress condition. table 4. interaction effect of water stress and variety on yield and yield contributing characters of boro rice treatments filled grains panicle-1 (no.) unfilled grains panicle-1 1000 grain weight (g) grain yield (t ha-1) straw yield (t ha-1) biolo-gical yield (t ha-1) harvest index (%) w1v1 123.63 abc 16.40 abc 21.13 d 5.63 def 6.10 d 11.72 ef 48.01 a w1v2 145.43 a 16.47 abc 18.26 e 7.31 bc 7.44 b 14.76 bc 49.55 a w1v3 100.07 de 16.70 abc 17.23 f 5.59 ef 5.93 d 11.52 ef 48.68 a w1v4 102.73 cde 8.40 c 25.37 bc 6.33 de 7.30 bc 13.63 cd 46.46 ab w1v5 126.57 ab 9.437 c 26.10 b 7.65 b 8.73 a 16.39 ab 46.69 ab w1v6 108.67 b-e 14.97 abc 25.47 bc 8.64 a 8.91 a 17.55 a 49.19 a w2v1 118.87 bcd 26.13 a 25.47 bc 4.65 g 5.30 d 9.95 f 46.68 ab w2v2 121.13 bcd 21.93 ab 18.49 e 6.16 def 6.23 cd 12.39 de 49.72 a w2v3 104.23 b-e 26.13 a 17.10 f 4.52 g 5.90 d 10.42 f 43.66 b w2v4 98.90 de 12.57 bc 25.01 c 5.36 fg 5.80 d 11.17 ef 47.94 a w2v5 107.77 b-e 14.47 abc 27.00 a 6.52 cd 7.45 b 13.96 cd 46.67 ab w2v6 89.10 e 19.03 abc 25.33 bc 7.31 bc 8.15 ab 15.47 bc 47.32 ab lsd(0.05) 23.19 12.86 0.93 0.89 1.06 1.63 4.05 cv (%) 12.13 25.01 2.45 8.31 8.94 7.42 5.00 w1nowater stress, w2water stress and v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5 brri hybrid dhan3, v6aloron. 104 aup et al. effect of water stress on grain growth pattern panicle weight was significantly influenced by water stress at 5, 10, 15, 20, 25 days after anthesis and at harvest (figure 1). panicle weight increased from 5 days after anthesis up to harvest for both no water stress and water stress condition. panicle weight was reduced by about 7% at harvest due to water stress condition at reproductive stage. fofana et al.(2010)found that effect of water stress on yield was most severe when drought occurred during panicle development. this might be associated with low dry matter production during the drought period as well as during the recovery period following the drought. when drought occurred during grain filling, the percentage of filled grain was decreased to 40% and individual grain mass decreased by 20% (sarvestani et al., 2008). mannan et al. (2012) also found variation in grain development due to water deficit condition. w1-no water stress,w2-water stress (lsd (0.05) value = 0.06, 0.33, 0.23, 0.29, 0.24 and 0.11 at 5, 10, 15, 20, 25 days after anthesis and at harvest, respectively). fig.1. effect of water stress on panicle weight at different days after anthesis effect of variety on grain growth pattern varietal variances showed significant difference in anthesis development. panicle weight was significantly influenced by different varieties at 15, 25 days after anthesis and at harvest but statistically similar at 5 and 10 days after anthesis (figure 2). panicle weight of all the tested varieties was increased throughout the grain development period with a little fluctuation. at harvest, maximum panicle weight was recorded in brri hybrid dhan3 (4.61 g) which was statistically similar with aloron (4.42g). on the other hand, brri dhan50produced the minimum panicle weight at harvest (2.30 g).these findings corroborated with the findings of murshida et al. (2017). 0 0.5 1 1.5 2 2.5 3 3.5 4 5 10 15 20 25 at harvest p a n ic le w t. ( g ) days after anthesis w1 w2 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5 10 15 20 25 at harvest p a n ic le w t. ( g ) days after anthesis v1 v2 v3 v4 v5 v6 growth, grain development and yield performance of boro rice 105 v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5brri hybriddhan3, v6aloron (lsd (0.05) = ns, ns, 0.61, 0.56, 0.46 and 0.75 at 5, 10, 15, 20, 25 days after anthesis and at harvest, respectively). fig. 2. effect of variety on panicle weight at different days after anthesis interaction effect of water stress and varietyon grain growth pattern panicle weight was significantly influenced by the interaction of water stress and variety at 15, 20, 25 days after anthesis and at harvest but statistically insignificantat 5 and 10 days after anthesis (table 5). table 5. interaction effect of water stress and variety on panicle weight at different days after anthesis treatments 5 days 10 days 15 days 20 days 25 days at harvest w1v1 1.3 1.45 2.70 a-d 2.74 a-e 2.76 cd 2.78 d w1v2 0.80 1.33 1.73 de 2.78 a-e 2.73 cd 3.34 bcd w1v3 0.73 2.00 2.31 a-e 2.25 def 2.38 cde 2.39 d w1v4 0.72 1.04 3.04 ab 3.40 a 3.50 ab 3.52 a-d w1v5 0.71 1.10 2.77 abc 3.29 ab 4.01 a 4.84 a w1v6 0.74 1.22 3.20 a 3.08 abc 3.95 a 4.46 ab w2v1 0.52 0.97 2.05 b-e 2.40 c-f 2.41 cde 2.63 d w2v2 0.68 1.17 1.36 e 1.88 f 2.08 e 3.32 bcd w2v3 0.73 1.30 1.98 cde 2.047 ef 2.19 de 2.32 bcd w2v4 0.66 1.13 2.10 b-e 2.64 b-f 2.96 bc 3.03 cd w2v5 0.67 0.96 2.35 a-e 2.89 a-d 3.56 ab 4.39 abc w2v6 0.66 1.47 2.91 abc 2.71 a-e 3.80 a 4.38 abc lsd(0.05) ns ns 1.00 0.79 0.65 1.41 cv (%) 16.49 28.80 14.05 17.34 12.54 13.67 w1no water stress, w2water stress and v1brri dhan28, v2brri dhan29, v3brri dhan50, v4binadhan-10, v5 brri hybriddhan3, v6aloron. panicle weight of all the tested varieties was reduced due to water stress at reproductive stage. grain development of brri dhan29 was least affected by water stress while the most affected variety was binadhan-10. panicle weight of binadhan-10 at harvest was declined by 14% due to water stress. sokoto and muhammad(2014)reported that applied moisture stress during reproduction phase reduced yield with the magnitude of yield reduction being 25.8% (average of reproduction in booting, flowering and grain filling stage) compared to control. fofana et al. (2010)alsoshowed that stress at booting and flowering stages had the similar effect on grain yield. conclusion considering the above results, it may be concluded that water stress at reproductive stage significantly reduces the grain yield. among the tested varieties, aloron performed best under water stress condition. so, in the region, where the irrigation water is a matter of concern in case of cost and availability, the variety aloron may be a better option to cultivate as it provides equal yield as mega variety brri dhan29 under no water stress condition.however, further experimentation will need to be executed in different agro-ecological zones with more varieties under water stress condition to reach a specific conclusion and recommendation. references anonymous. 1988. the year book of production. fao, rome, italy. bbs (bangladesh bureau of statistics). 2020. statistical yearbook of bangladesh for 2020. bureau of statistics, statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. 106 aup et al. caine, r.s., x. yin, j. sloan, e.l. harrison, u. mohammed, t. fulton, a.k. biswal, j. dionora, c.c. chater, r.a. coe, a. bandyopadhyay, e.h. murchie, r. swarup, w.p. quick andj.e. gray.2019.rice with reduced stomatal density conserves water and has improved drought tolerance under future climate conditions. new phytol. 221(1): 371–384. castilo, e, j. siopongco, r.j. buresh, k.t. ingram and s.k.d. datta. 1987. effect of nitrogen timing and water deficit on nitrogen dynamics and growth of lowland rice. irri saturday, 7 november 1987. los banos, laguna, phillippines. chowdhury, m.j., m.t. islam, and m.o. islam. 2004. evaluation of two local transplant aman rice cultivars and a mutant under soil moisture stress. bangladesh j. soc. agril.sci. technol.1(1&2): 127–131. fofana, m., m. cherif, b. kone, k. futakuchi and a. audebert. 2010. effect of water deficit at grain repining stage on rice grain quality. j. agric. biotech. sustain. dev. 2(6): 100–107. frg. 2012. fertilizer recommendation guide. bangladesh agricultural research council (barc). farmgate, dhaka 1215. p.74. gardner, f.p., r.b. pearce and r.l. mistechell. 1985. physiology of crop plants. iowa state univ. press, powa. p.66. halder, k.p., m.s. islam, m.r. manir and m.a. ali. 2018. moisture stress and different rates of nutrients on growth and yield of rice. bangladesh rice j. 22(2): 23–30. halder, k.p. and s.w. burrage. 2003. drought stress effects on water relations of rice grown in nutrient film technique. pak.j.biol.sci. 6 (5): 441-444. keller, m. 2005. deficit irrigation and vine mineral nutrition. american j. enol. vitic. 56: 267–283. maneepitak, s., h. ullah, a. datta, r. shrestha, s. shrestha and b. kachenchart. 2019. effects of water and rice straw management practices on water savings and greenhouse gas emissions from a doublerice paddy field in the central plain of thailand. european j. agron. 107:18–29. mannan m.a., m.s.u. bhuiya, m.i.m. akhand and m.m. zaman. 2012. growth and yield of basmati and traditional aromatic rice as influenced by water stress and nitrogen level. j. sci. found.10(2):52– 62. molden, d., t. oweis, p. steduto, p. bindraban, m.a. hanjra and j. kijne. 2010. improving agricultural water productivity: between optimism and caution. agric. water mngt. 97: 528–535. mostajeran, a. and v. rahimi-eichi. 2009. effects of drought stress on growth and yield of rice (oryza sativa l.) cultivarsand accumulation of proline and soluble sugars in sheathand blades of their different ages leaves. american-eurasian j. agric. environ. sci. 5(2): 264–272. murshida, s., m.r. uddin, m.p. anwar, u.k. sarker, m.m. islam and m.m.i. haque. 2017. effect of variety and water management on the growth and yield of boro rice. progress. agric.28(1): 26–35. sabetfar, s., m. ashouri, e. amiri and s. babazadeh. 2013. effect of drought stress at different growth stages on yield and yield component of rice. persian gulf crop protect. 2(2): 14–18. sarvestani ,z.t., h. pirdashti, s.a.m.m. sanavy and h. balouchi . 2008. study of water stress effects in different growth stages on yield and yield components of different rice (oryza sativa l.) cultivars. pak. j. biol. sci. 11(10):1303–1309. sokoto, m.b. and a. muhammad. 2014. response of rice varieties to water stress in sokoto, sudan savannah, nigeria. j. biosc. medicines. 2: 68–74. waraich, e.a., r. ahmad, saifullah, m.y. ashraf and ehsanullah. 2011. role of mineral nutrition in alleviation of drought stress in plants. australian j. crop sci. 5: 764–777. zubaer, m.a., a.k.m.m.b. chowdhury, m.z. islam, t. ahmed and m.a. hasan. 2007. effects of water stress on growth and yield attributes of aman rice genotypes. intl. j. sustain. crop prod. 2(6): 25– 30. https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=caine%2c+robert+s https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=yin%2c+xiaojia https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=sloan%2c+jennifer https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=harrison%2c+emily+l https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=mohammed%2c+umar https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=fulton%2c+timothy https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=biswal%2c+akshaya+k https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=dionora%2c+jacqueline https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=chater%2c+caspar+c https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=chater%2c+caspar+c https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=coe%2c+robert+a https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=bandyopadhyay%2c+anindya https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=murchie%2c+erik+h https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=swarup%2c+ranjan https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=quick%2c+w+paul https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=gray%2c+julie+e https://nph.onlinelibrary.wiley.com/action/dosearch?contribauthorraw=gray%2c+julie+e https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/sumana-maneepitak https://www.researchgate.net/profile/hayat-ullah-2 https://www.researchgate.net/profile/avishek-datta-3 https://www.researchgate.net/profile/rajendra-shrestha-6 https://www.researchgate.net/profile/sangam-shrestha https://www.researchgate.net/scientific-contributions/boonlue-kachenchart-2066579939 https://pubmed.ncbi.nlm.nih.gov/?term=sarvestani+zt&cauthor_id=18817260 https://pubmed.ncbi.nlm.nih.gov/?term=pirdashti+h&cauthor_id=18817260 https://pubmed.ncbi.nlm.nih.gov/?term=sanavy+sa&cauthor_id=18817260 https://pubmed.ncbi.nlm.nih.gov/?term=balouchi+h&cauthor_id=18817260 bangladesh agron. j. 2024, 27(1): 48-54 effect of soil amendments on tomato yield and soil characteristic in acidic soil at moulvibazar m. shaheenuzzamn1*, m.s. alam2, m.a.m miah2, m. rasheduzzaman2, m.h. hossain3 and f. sinthi4 1pulse research sub-station, bangladesh agricultural research institute, gazipur, bangladesh 2regional agricultural research station, bangladesh agricultural research institute, moulvibazar, bangladesh 3chief scientific officer, regional agricultural research station, bangladesh agricultural research institute, cumilla, bangladesh 4department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh *corresponding author, email: shaheenuzzamn@gmail.com (received: 12 february 2025, accepted: 17 april 2025) keywords: amendments, acidic soil, high temperature, tomato abstract different soil amendments have various effects on crop growth, yield, and soil properties. the experiment was followed a randomized complete block design (rcbd) with three replications. data on tomato growth and yield were collected, and soil samples were analyzed before and after the cropping seasons. results showed that all amendments significantly increased tomato growth and yield compared to the control (no soil amendments). however, the amendments did not significantly affect days to first flowering (dff), fruit length (fl), fruit diameter (fd), average fruit weight (afw), fresh weight per plant (fwpp), or dry matter per plant (dmpp). in contrast, days after 50% flowering (d50 %f), plant height (ph), number of branches per plant, number of fruits per plant (nfpp), number of fruits per plot (nfpp), and yield per hectare (yph) were significantly influenced by the soil amendments. additionally, the shelf life of tomatoes was significantly (p > 0.001) affected by the amendments on acidic soil. regarding soil properties, lime, phosphorus, and trichoderma improved soil chemical properties. the findings confirm that applying soil amendments enhances tomato growth, yield, and quality. introduction tomato (lycopersicon esculentum mill.) is the most popular vegetable globally grown (araujo et al., 2016). the popularity of tomato among consumers is not only because of its good taste, but also because it contains high levels of vitamin c, lycopene, and beta-carotene, which are antioxidants that promote good health. soil acidity is a significant challenge in many agricultural regions, particularly in tropical and subtropical areas, where acidic soils often have low fertility and poor structure, limiting crop production. the cultivation of tomatoes (solanum lycopersicum), a widely grown and economically important crop, is especially impacted by such unfavorable soil conditions. soil amendments, including the use of lime, organic materials, and chemical fertilizers are commonly applied to improve both soil characteristics and crop yield in acidic environments. one of the most effective strategies for managing soil acidity is liming, which neutralizes acidic soils by increasing ph, improving the availability of essential nutrients, and reducing toxic elements like aluminum and manganese (rengel, 2011). phosphorus (p) availability is also a key issue in acidic soils, as it becomes less accessible to plants when soil ph is low. amending the soil with p fertilizers can improve nutrient uptake and support root growth, which is critical for enhancing crop yield (fageria and baligar, 2008). organic amendments, such as compost and biochar, can improve soil structure, water retention, and microbial activity, further boosting plant growth and soil health (sohi et al., 2010). additionally, the introduction of trichoderma 49 shaheenuzzamn et al. fungi has been demonstrated to improve plant resistance to pathogens, enhance nutrient absorption, and promote plant growth by modifying root systems and soil properties (harman et al., 2004). research on the combined effects of these amendments has shown that the application of lime, p, and organic materials in acidic soils can significantly improve tomato yield by enhancing soil physical and chemical properties. studies have reported increases in soil ph, improved nutrient availability, and better root development, all of which contribute to higher crop productivity. previous findings also suggest that a balanced application of lime, p, and trichoderma significantly enhances tomato yield by improving soil characteristics, such as ph balance, nutrient availability, and microbial activity. the integration of organic and inorganic amendments offers a sustainable approach to managing acidic soils and improving long-term soil fertility in agricultural systems. the study was done to assess the effect of soil amendments on tomato growth, yield and soil properties. materials and methods experimental location and soil the experiment was conducted at the regional agricultural research station, bari, akbarpur, moulvibazar during rabi season of 2021-2022 and 2022-23 to find out the effects on tomato growth, yield and soil properties at acidic soil condition. the site belongs to the agro-ecological zone of eastern surma-kushiyara floodplain (aez-20) and northern and eastern hills (aez-29). the experimental field situated at 24°24 ′-24°38 ′ n latitude and 91°37 ′-91°37 ′ e longitude. the soil series belongs to the “khadimnagar” having sandy loam in texture which consist moderate organic matter content (1.45%), n 0.80%, k 0.07m mol 100 g−1 of soil, p was 25 μg g−1 of soil and s was 10 μg g−1 of soil with ph value 4-5. each year, soil chemical properties in the experimental field were measured before and after the cultivation of groundnut (table 1.) to check whether leguminous crop increases soil ph and organic matter or not. the metreological data such as maximum temperature (°c), minimum temperature (°c), uv index, precipitation (mm), and relative humidity (%) of the research site throughout the study duration from september 2021 to may of 2022 and september 2022 to may of 2023 cropping seasons are presented in fig. 1 and 2. which were collected from weather station of sreemongal, sylhet, 12 km far from the experimental field. fig. 1 (a-b). meteorological data for the research site, showing maximum temperature (°c), minimum temperature (°c), uv index, number of rainy days and relative humidity (%) during the years 20212022 and 2022-2023. design and treatments the experiment was laid out in randomized complete block design (rcbd) with three replications. the treatments of the experiment were 5 (five) viz., t1= fertilizer effect of soil amendments on tomato yield and soil characteristic in acidic soil 50 recommendation guide (frg); t2= frg with p (60 kg ha−1); t3= frg with lime (2 t ha−1); t4= frg with p (30 kg ha−1) + lime (2 t ha−1), and t5= frg with lime (2 t ha−1) +trichoderma (2 t ha−1). fertilizer management the crop was fertilized with 160-60-80-28-3-1.5 kg ha−1 n-p-k-s-zn-b in the form of urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate, and boric acid, respectively (frg, 2018). half of the quantity of k and organic fertilizer, entire p, zn, and b were applied during land preparation. the remaining half of the organic fertilizer was used during pit preparation. the rest of k and entire n were applied at two equal installments at 15 and 30 days after transplanting under moist condition and mixed thoroughly with soil as soon as possible. before applying the fertilizer doses, the chemical properties of the experimental plots were recorded and presented in table 1a. post harvest soil analysis was also done which depicted in table 1b. table 1a. initial chemical properties of experimental soil at rars, akbarpur, moulvibazar table 1b. final chemical properties of experimental soil at rars, akbarpur, moulvibazar t1=frg recommendation, t2= frg with p (60 kg ha−1), t3= frg with lime (2 t ha−1), t4= frg with p (30 kg ha−1) + lime (2 t ha−1), t5= frg with lime (2 t ha−1) +trichoderma (2 t ha−1). crop management and protection a light irrigation was done at just after transplanting in each seedling for establishment. thereafter, flood irrigation was applied for three times at 30, 40, and 80 dap, and other intercultural operations were done as when necessary, following the recommended production technologies of the tomato crops (bari, 2020). hand weeding was done twice at the plant establishment and flowering stage. some leaves and emerging twigs were pruned during the cropping season. diseases like leaf spot, root rot, rust, wilt, and insect pests viz., termite, leaf minor were control through recommended insecticides and fungicide. the seedlings of tomato variety (bari tomato-15) were transplanted on 15 and 18 november, 2022 and 2023, respectively. the crops were harvested when attained to their respective physiological maturity. the unit plot size was 3 m × 2.75 m. statistical analysis data were collected in relation to phenology, yield attributes, yield, and quality of tomato. the data recording for each trait (3) was carried out from all replications. the recorded agronomic data were subjected to the analysis of variance (anova) using r software, version location ph om (%) ca mg k total n% p s b cu fe mn zn meq 100 g−1 µg g−1 rars, moulvibazar 4.3 1.61 1.70 0.42 0.40 0.08 42.5 13 0.54 0.76 63 19.11 0.24 critical level c: n=10:1 2.0 0.8 0.20 0.12 10 10 0.2 1 10 5 0.6 treatment ph om (%) ca mg k total n% p s b cu fe mn zn meq 100 g−1 µg g−1 t1 4.5 1.71 1.73 0.96 0.45 0.048 93.38 86.91 0.68 0.87 355.20 15.00 3.69 t2 4.6 1.86 1.60 0.93 0.55 0.038 107.05 97.49 0.66 0.93 378.60 17.10 3.75 t3 4.8 1.96 3.87 1.46 0.53 0.048 78.16 107.49 0.40 0.93 346.50 12.00 2.64 t4 4.9 2.26 5.58 1.29 0.48 0.065 78.94 124.02 0.50 1.02 350.70 11.10 2.97 t5 5.0 2.57 7.22 1.02 0.51 0.089 90.76 27.20 0.52 0.99 289.50 4.80 2.01 51 shaheenuzzamn et al. 4.3.1 (r core team, 2019), and mean separation was carried out using the least significant difference (lsd) test at a 5% probability level by gomez and gomez (1984). results and discussion changes of post-harvest soil properties the results of the study showed that soil ph and organic matter increased significantly when added p, lime, and trichoderma with approved fertilizers to acidic soils. depending on different treatments soil ph increased by 5-16% and organic matter increased by 6-60%. the maximum soil ph (16%) and organic matter (60%) were increased where lime and trichoderma were applied with recommended fertilizers where the lowest value was observed where only approved fertilizers were used. the order of soil acidity and organic matter among different treatments was t5>t4>t3>t2>t1. similar results were observed for ca. in case of mg, higher values were obtained where lime was applied with recommended fertilizers (t3) and lower where p was applied (t2). for k higher values were obtained where p was applied (t2) and lower values where only approved fertilizer levels were used (t1). the percentage of total nitrogen (n) was lower where p was applied with approved fertilizers (t2) and higher where lime and trichoderma were added (t5). naturally p excess was observed where p was applied with approved fertilizers (t2) and p deficiency was observed where lime was applied (t3). s values were found to be higher when p and lime were added with recommended fertilizers (t4) and significantly reduced s values where lime and trichoderma were added (t5). b values were observed to be higher at the approved fertilizer levels (t1) and lower where lime was applied (t3). cu was higher where p and lime were added (t4) and lower where only p or lime was applied (t2 and t3). fe content was found to be higher where p was applied (t2) and lower where lime and trichoderma were applied (t5). similar results were obtained for mn and zn. overall, the results provide key insights into the effects of adding p, lime, and trichoderma, along with approved fertilizers, on acidic soils. the combination of lime and trichoderma with approved fertilizers had the most significant positive impact on soil ph, organic matter, and n content (t5). p applications led to higher k and fe levels but resulted in lower n and mg content. lime application played a key role in increasing ca and mg levels but led to p and b deficiencies. these results suggest that amendments involving lime, p, and trichoderma, depending on the target nutrients, can optimize soil health in acidic environments. phenology, yield contributing traits and yield of tomato the results showed that soil amendments had no significant effect on days to first flowering (dff), fruit length (fl), or fruit diameter (fd) of tomatoes grown in acidic soil (table 2). however, amendments significantly influenced days after 50% flowering (d50 %f), plant height (ph), number of branches per plant, and number of fruits per plant (nfpp) in tomatoes. t1 treatment recorded the longest days after 50% flowering (d50 %f) (35 days), followed by t4 with 34 days and t5 with 34 days. t1 also showed the highest d50 %f at 40 days, followed by t5 (40 days) and t4 (39 days). in terms of plant height, t5 produced the maximum plant height (112.42 cm), followed by t2 at 110.77 cm in acidic soil. these findings suggest that soil amendments with fertilizers were effectively utilized by the tomato plants, leading to significant growth in plant height. this supports previous research by ortas (2013), which showed that soil amendments in various fertilizer forms enhanced tomato plant height. the number of tomato branches was also positively influenced by the amendments, promoting greater vegetative growth. treatment t4 recorded the maximum nfpp (52.00), followed by t3 with 49.67 fruits, and t1 with 47.67 fruits. this variation in fruit number was due to differences in nutrient release from the amendments. as shown in table 3. the nfpp and fruit yield per hectare (yph) were significantly influenced by the soil amendments, while shelf life was highly significant. however, average fruit weight (afw), fresh weight per plant (fwpp), and dry matter per plant (dmpp) were not significantly affected. treatment t5 recorded the maximum nfpp (858.0), followed by effect of soil amendments on tomato yield and soil characteristic in acidic soil 52 t2 (846.33), while t4 had the lowest (700.0). treatment t2 produced the maximum yph (68.99 t ha−1), followed by t3 (68.04 t ha−1) and t4 (63.38 t ha−1), while t1 had the lowest fruit yield (59.32 t ha−1). the results showed that yield-contributing factors were higher in p-treated plants compared to control. regarding shelf life, t3 and t4 showed the longest shelf life after harvest (30 and 28 days, respectively), followed by t2 (25 days). treatment t1 recorded the shortest shelf life (14 days) for tomatoes. table 2. effect of different soil amendments on yield and yield-related traits on tomato at acidic soil (pooled average of 2021-2022 and 2023-24) treatment days to first flowering (days) d50 %f (days) plant height (cm) flowering length (cm) fruit diameter (cm) branches plant−1 number of fruits plant−1 average fresh weight (g) t1 35 40 109.2 4.9 4.23 4.76 47.67 42.89 t2 32 37 110.77 5.47 4.46 4.43 46.33 46.45 t3 34 39 108.87 5.07 4.23 4.77 49.67 45.12 t4 34 39 107.97 5.07 4.4 4.89 52 45.99 t5 34 40 112.42 5.17 4.13 4.89 44.33 50.63 cv (%) 5.51 4.95 4.04 8.95 8.7 14.5 12.54 8.79 lsd (0.05) 3.51 3.63 8.35 0.86 0.70 1.23 11.33 7.64 here, t1=frg (2018), t2= frg with p (60 kg ha−1), t3= frg with lime (2 t ha−1), t4= frg with p (30 kg ha−1) +lime (2 t ha−1), t5= frg with lime (2 t ha−1) +trichoderma (2 t ha−1). table 3. effect of different soil amendments on yield and yield-related traits on tomato at acidic soil (pooled average of 2021-2022 and 2023-24) treatment fresh weight per plant (g) dry matter per plant (gm) fruits plot−1 yield per plot (kg) yield (t ha−1) shelf life (days) total soluble solids t1 250.67 31.23 740.67 16.31 59.32 13.51 4.75 t2 282.67 35.18 846.33 18.97 68.99 25.08 4.73 t3 262.67 32.86 710.67 18.71 68.04 30.91 4.97 t4 330.22 33.71 700.67 17.43 63.38 28.06 4.7 t5 200.33 34.21 858.67 17.76 64.59 21.68 4.81 cv (%) 14.53 14 8.62 18.78 18.78 13.83 6.03 lsd (0.05) 72.58 8.81 125.22 6.30 22.94 6.21 0.55 here, t1=frg (2018), t2= frg with p (60 kg ha−1), t3= frg with lime (2 t ha−1), t4= frg with p (30 kg ha−1) +lime (2 t ha−1), t5= frg with lime (2 t ha−1) +trichoderma (2 t ha−1). correlation analysis among the studied traits under the study, all the phenological and yield contributing traits were exhibited positive and negative correlation from each other’s (fig. 2). the traits dff perform positive significant correlation (p= 0.05 level) with days to flowering (df), fruit length (fl), dmpp, yield per plot (ypp) and yield per hactare (yph). this indicates that as the dff increase, these traits tend to increase as well, potentially leading to higher yields per plot and per hectare. plant height showed positive significant correlation (p=0.05 level) with number of fruits plant−1 (nfpp) and number of fruit plot−1 (nfpp). this suggests that taller plants are associated with an increased number of fruits, which may contribute to higher overall yield. similarly, fl, nfpp and ypp traits present positive significant correlation with dmpp, fpp and yph, respectively. these relationships suggest that improvements in these traits are likely to enhance the dry matter content, fruit count, and overall yield. rest of the traits showed positive and negative insignificant correlation with one to another. the lack of significance in some cases implies that these traits might not directly influence one another in a consistent manner under the conditions 53 shaheenuzzamn et al. studied. for instance, early flowering (dff) might be negatively associated with traits such as ph, suggesting that earlier flowering plants may be shorter and potentially produce fewer fruits per plant. these findings have practical implications for tomato breeding programs. traits that exhibit strong positive correlations with yield components, such as dff with ypp and yph and ph with nfpp and fpp are valuable targets for selection. improving these traits may lead to higher yields, both per plot and per hectare. fig. 2. correlation of phenological and yield contributing traits with fruit yield of tomato (dff= days to first flowering; df= days to flowering (50%), ph= plant height; fl= fruit length; fd= fruit diameter; brpp= branches plant−1; nfpp= number of fruits plant−1; afw= average fruit weight; fwpp= fresh weight plant−1; dmpp= dry matter plant−1; fpp= number of fruit plot−1; ypp= yield per plot; yph= yield per hectare) conclusion the study showed that soil amendments such as lime, p, and trichoderma significantly improved tomato growth, yield, and soil properties in acidic soil. the combination of lime and trichoderma with recommended fertilizers was particularly effective, enhancing soil ph, organic matter, and nitrogen content. p application resulted in higher k and fe levels but reduced mg and n. the findings confirm that appropriate soil amendments not only boost tomato productivity but also improve soil chemical characteristics, providing a sustainable solution for managing acidic soils in agriculture. references araujo, j.c., s.f.p. telhado, r.h. sakai, c.a.s. lebo and p.c.t. melo. 2016. univariate and multivariate procedures for agronomic evaluation of organically grown tomato cultivars. hortic. bras. 34(3): 374-380. bari. 2020. krishi projukti hatboi (handbook on agro-technology), 9th edition. bangladesh agricultural research institute, gazipur-1701, bangladesh. fageria, n.k. and v.c. baligar. 2008. ameliorating soil acidity of tropical oxisols by liming for sustainable crop production. adv. agron. 99: 345-399. frg. 2018. fertilizer recommendation guide. bangladesh agricultural research council (barc). farmgate, dhaka-1215. 223p. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. 2nd ed., a wiley interscience publication, john wiley and sons, singapore. pp. 302. effect of soil amendments on tomato yield and soil characteristic in acidic soil 54 harman, g.e., c.r. howell, a. viterbo, i. chet and m. lorito. 2004. trichoderma species-opportunistic, avirulent plant symbionts. nat. rev. microbiol. 2(1): 43-56. islam, m.r., m.a. alam, m.m. kamal, r. zaman, a. hossain, h. alharby, a. bamagoos, m. farooq, j. hossain, c. barutcular, f. çig. 2019. assessing impact of thermal units on growth and development of mustard varieties grown under optimum sown conditions. j. agrometeorol. 21(3): 270-281. islam, m.r., m.m. kamal, m.f. hossain, j. hossain, m.g. azam and m.s islam. 2021. productivity and profitability of turmeric (curcuma longa) and okra (abelmoschus esculentus) intercropping system for marginal farmers in north-western part of bangladesh. philipp. agric. scientist. 104(2): 114123. ortas, i. 2013. influences of nitrogen and potassium fertilizer rates on pepper and tomato yield and nutrient uptake under field conditions. academic j. 8(23): 1048-1055. r core team. 2019. r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. available at: http://www.r-project.org/ rengel, z. 2011. soil ph, soil health and climate change. soil health clim. change. 1: 69-85. sohi, s.p., e. krull, e.l. capel and r. bol. 2010. a review of biochar and its use and function in soil. adv. agron. 105: 47-82. bangladesh agron. j. 2021, 24(2): 137-149 light interception and productivity of maize intercropped with legumes in kharif season q. naher and m.a. hossain onfarm research division, bari,gazipur 1701, bangladesh corresponding e-mail: ofrdjoy@yahoo.com (received: 09 december 2021, accepted: 19 december 2021) keywords:light interception, maize legume intercropping, weed growth, productivity abstract the experiment was carried out at the bangladesh agricultural research institute, joydebpur, gazipur during 2012 to evaluate the intercepted par in maize intercropped withlegumein comparison to monoculture for better weed suppression, productivity and economic benefits in kharif season. there were 17 treatments in the experiment viz., t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram( weeding at 20 dae), t12= maize + blackgram( weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free), t15= sole mungbean (weed free), t16=sole soybean (weed free) and t17= sole blackgram (weed free).the results showed that par was significantly affected by cropping system, where it was higher in intercropping systems compared to sole crop . regarding weed control, intercrops were more effective than sole crops and it was related to lower availability of par for weeds in intercropping systems. the highest grain yield (8.05 t ha-1). was obtained from weed free sole maize among all intercropping, maize + mungbean along with two hand weeding gave the highest yield (maize: 7.18 t ha-1; 572.6 kg ha-1 mungbean), maize equivalent yield (mey) = 12.49t ha-1and bcr = 2.84). from the study it can be concluded that maize mungbean intercropping with two hand weedings at 20 and 40 dae would be the best in reducing weed growth, producing maximum yield and net return in intercropping systems under kharif season. introduction maize (zeamays l.) is the third most important cereal next to rice and wheat, in the world as well in bangladesh. many factors are responsible for the low yields of maize in bangladesh.the average yield of maize in bangladesh is 3.0 t/ha (bbs, 2017) which is too low compared tomanyother countries. weedis one of the major constraints of maize production in our country. they cause yield losses worldwide with an average of 12.8 per cent despite weed control practices and 29.2% in case of unchecked weed growth (dogan et al., 2004). although maize plant is vigorous and tall in nature, yet it is very sensitive to weed competition at early stages of growth. hence, it is necessary that maize should be kept free of weeds for the first 30 days after crop emergence. now-a-days, the labour force is diminishing in agriculture. management of weeds in cropped field has become a real challenge to the farmers. the production and productivity of maize is reduced due to competition offered by weeds for growth resources viz., nutrients, moisture, sunlight and space during entire vegetative growth and early reproductive stage. intercropping is an agricultural practice which can be used for decreasing the dependency on chemical herbicides in weed control (banik et al., 2006).intercropping generates beneficial biological intermailto:ofrdjoy@yahoo.com 138 naher et al. actions between crops increasing grain yield and stability, more efficient using available resources and reducing weed pressure (kadziuliene et al., 2009). many authors indicated the limiting effect of intercropping on the number and biomass of weeds (gharineh and moosavi, 2010). weed suppression in intercropping through more efficient use of environmental resources by component crops has been reported (poggio, 2005). light interception and light use efficiency (lue) of crops directly determine dry matter accumulation and yield formation, depending on canopy traits such as the distribution and photosynthetic capacity of the leaves (gao et al., 2010). higher light interception or a higher lue can result in greater productivity. numerous studies reported that yield advantage in intercropping was mainly due to greater light interception and use efficiency. katsaruware and manyanhaire (2009) reported that maize-cowpea intercrops reduced weed biomass when compared to sole crops and it was as a result of limited availability of resources to weed species, where incoming par reaching the ground was reduced by maize-cowpea intercrop. baumann et al. (2000) reported that intercropping increase light interception by the weakly competitive component and can, therefore, shorten the critical period for weed control and reduce growth and fecundity of late-emerging weeds.the tall maize c4 plants canopy provides greater light penetration so that better light distribution is available over the leaves located in lower state. the under storey short stature c3 legume crop is shaded but this is partially offset by its higher photosynthetic rates per unit radiant energy at a low light intensity and it may be compatible crop as intercrop with maize (muoneke et al., 2007). among the intercrops, blackgram, greengram, soybean and cowpea were generally found to increase the yield of maize or gave similar yield along with an additional yield of intercrop (li et al., 2001). the aim of the present study was to quantify the effect of intercropping on weed suppression by evaluating the amount of photosynthetically active radiation (par) consumption. materials and methods the experiment was conducted at the on-farm research field of bangladesh agricultural research institute, joydebpur, gazipurduring kharif season of 2012. the experiment site was located at chhiata series under agro-ecological zone-28. before opening the land, the soil samples were taken and showed that the soil of the experimental field was loam in texture and low in organic matter (1.16%). the soil ph is 7.2 and contained very low amount of total nitrogen (0.061%), phosphorus (3 g/g), sulphur (0.6 g/g), zinc (3.54 g/g), boron (0.44 g/g) and potassium (0.13 meq./100g soil).during the crop growth period average monthly maximum temperature was recorded in the month of april (22.5° c). there were 17 treatments in the study viz., t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram( weeding at 20 dae), t12= maize + blackgram (weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) t14 =sole maize (weed free), t15=sole mungbean (weed free), t16=sole soybean (weed free) and t17= sole blackgram (weed free)were studied. maize was sown in 75 cm20 cm spacing both in sole and intercrop system. planting arrangement in intercrop treatments, two rows of legumes accommodated between one row of maize.the trialwaslaid out in a randomized complete block design with three replications. the plot size was 5.0m4.5m. maize var. bari hybrid maize-7, mungbean var. bari mung-5, blackgramvar. bari mash-3 and soybean var. bari soybean-5 were used as test crops. fertilizer was applied for maize at the rate of 250-50-100-44-5-2 kg of n, p, k,s, znand bha-1, respectively, from urea, triple super phosphate, muriate of potash, gypsum, zinc sulphate and boric acid, respectively. half amount of n and full dose of other fertilizers were incorporated into the soil at the time of final land preparation. the remaining urea was top dressed in two equal installments as top dressing at 8-10 leaf stage (30-35 das) and at tasseling stage (55das) followed by irrigation. fertilizers were applied for sole mungbean, blackgram and soybean at the rate of 21-17-18 and 23-18-18 kg of n, p, k ha-1, respectively from urea, tsp, mop, respectively. half light interception and productivity of maize intercropped 139 amount of urea and full amount of other fertilizers were applied at the time of final land preparation. additional fertilizers were not applied for legumes in intercrop situation. urea was top dressed as band placement in maize rows only. sowing of both maize and legumes were done on 15march 2012. weed management was done as per treatment specification. mature mungbean and blackgram were harvested at 65 dae while soybean was harvested at 100 dae. maize was harvested at 120das. legume equivalent yield and maize equivalent yield were computed using the formula of bandyopadhaya (1984). maize equivalent yield= yim + (yil pl)/pm where, yil = yield of intercrop legume (t ha-1) yim = yield of intercrop maize (t ha-1) pm = selling price of maize pl = selling price of legume weed control efficiency (wce) was calculated using the following formula (curz et al., 1986). wce = 100 dwc dwt-dwc  dwc = dry weight of weeds in the weedy check dwt = dry weight of weeds in the weeding treatment the portion of intercepted par (parint) was calculated using the following equation and expressed in percentage (ahmed et al., 2010). parint (%) = 100 parinc part-parinc  where, parint = intercepted par, parinc = incident par and part = transmitted par the collected data were statistically analyzed by using mstat programme and the means were adjudged by using lsd. economic analysis was also done. results and discussion weed density, weed dry weightand weed control efficiency (wce) asaffected by different intercropping systems and weeding regime are presented in table 1. intercropping systems significantly reduced the weed population and weed dry biomass than sole cropping of maize under unweeded situation. cynodondactylon, eleusineindica, echinochloa crus-galli, paspalumconjugatum, cyperusrotundus l. and physalisheterophyll were the common and dominant weeds in the maize field. maximum weed density (363.3m-2 at 20 dae and 426m-2 at 40 dae) and weed dry weight (216.8g at 20 dae and 284.4g at 40 dae) were recorded in unweeded monoculture maize crop. among the three different intercropping systems, t5(maize + mungbean with two hand weeding sat 20 and 40 dae) treatment provided the lowest weed density (275.3 m-2 at 20 dae and 53.33 m-2 at 40 dae) and weed dry weight (184.3 g at 20 dae and 14.07 g at 40 dae) and it was followed by maize + soybean and maize + blackgram systems. the reduction in weed population and weed dry biomass in intercropping systems mightbe attributed to shading effect and competition stress created by canopy of more number of crop plants in a unit area having suppressing effect on associated weeds thus preventing the weeds to attain full growth. similar results were reported by dwivedi and shrivastava (2011).at 20 dae, the weed control efficiency (wce) in all the treatments was almost same while at 40 dae the wce varied significantly in all treatments. weed control efficiency of different treatments varied from 14.8-25.3% at 20 dae and 17.9-87.53% at 40 dae. among the weed control treatments, two hand weeding sat 20 and 40 dae in maize + mungbean caused the highest weed control efficiency (24.0-87.5%) while it 140 naher et al. was (19.55-85.46%) in maize + soybean and (19.82-80.09%) in maize + blackgram treatments. pandey and prakash (2002) reported that maize and legume intercropped either as paired rows + two rows of legume or one row of legume in between two rows of maize adversely affected the weed growth and caused 22.4 and 31.9% weed growth suppression as compared with sole maize, respectively. among the intercropping systems, maize + soybean unweeded plot gave lower wce (18.83-22.34%). table 1. weed density, weed dry weight and weed control efficiency in different maize +legumes intercropping systems during the kharif season of 2012 treatments weed density (no. m-2) weed dry weight (g m-2) weed control efficiency (%) 20 dae 40 dae 20 dae 40 dae 20 dae 40 dae t1 363.3 a 426.0 a 216.8 a 284.4 a t2 284.7 cd 324.3 c 190.5 cde 178.0 b 21.32 abc 23.84 e t3 283.0 cd 113.0 d 189.1 cde 25.61 e 21.82 abc 73.40 d t4 270.7 d 326.3 c 181.2 e 157.9 c 25.25 a 23.27 e t5 275.3 cd 53.33 g 184.3 de 14.07 f 24.05 ab 87.53 a t6 293.3 bc 330.7 bc 196.3 bc 182.6 b 18.83 cd 22.34 e t7 286.0 cd 85.67 ef 192.2 cde 35.17 d 21.12 abc 79.82 bc t8 289.3 cd 333.3 bc 193.7 cd 163.9 c 20.13 bc 21.65 e t9 291.0 bcd 62.00 g 194.8 cd 17.50 ef 19.55 bc 85.46 ab t10 310.0 b 330.3 bc 207.5 ab 181.2 b 14.13 d 22.38 e t11 280.7 cd 64.00 fg 187.8 cde 17.67 ef 22.42 abc 84.96 ab t12 277.3 cd 349.3 b 185.6 cde 179.6 b 23.46 abc 17.87 e t13 290.3 bcd 99.33 de 190.3 cde 38.50 d 19.82 bc 76.71 cd cv (%) 4.48 6.49 8.32 3.10 13.99 6.91 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram( weeding at 20 dae), t12= maize + blackgram( weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae) photosynthetically active radiation (par) interception light/ solar radiation is the energy that drives crop productivity by the process of photosynthesis (keating and cerberry, 1993). it is an important resource essential for crop production. the plants use this resource to produce biomass and part of biomass is converted to economic yield (trenbath, 1986). percent radiation interceptions in different intercropping systems with varying weeding regimes in kharif season are presented in fig. 1. among the intercropping systems, maize + mungbean intercropping intercepted more light than maize + soybean and maize + blackgram systems at all growth stages. maize + mungbean with two hand weeding at 20 and 40 dae received more light (95%) at 50 dae which was followed by one hand weeding (90%) and no weeding (88%) treatments. same trend was observed in soybean and blackgram intercropping combinations. percent par interception was lower in earlier growth stages but it increased gradually up to 50 dae in mungbean and blackgram in maize + blackgram association with the increase of foliage coverage of maize and legumes. significantly the higher mean of par interception was recorded in intercrop treatments and sole cropped legume than that of sole cropmaize (eskandari, 2012). among the legume crops, the intensity and the quality of solar radiation intercepted by the canopy are important determinants of yield components and therefore yield of soybean since it is sensitive to shading (liu et al., 2010). light interception and productivity of maize intercropped 141 fig.1. photosynthetically active radiation interception of maize + legumes intercropping systems during the kharif season of 2012. light levels during the late flowering to mid pod formation stages of growth have been found to be more critical than during vegetative and late reproductive periods (liu et al., 2010). differences in varietal arrangement of foliage and canopy architecture of intercrop components may lead to more par interception by intercropping compared with sole crops (keating and carberry, 1993). total dry matter total dry matter (tdm) production of maizewas significantly influenced by different legume intercropping systems and weeding regimes (fig. 2). dry matter accumulation of maize increased slowly and attained plateau at around 80 dae and then the pattern of curves remained similar until harvest. the highest dry matter accumulation of maize (2065 g m-2) was obtained in monoculture. it might be due to utilized solar radiation and co2 as the plants were spaced planted with better nitrogen uptake and less weed infestation. similar results were reported by talukder et al. (2003).among the intercropping systems in maize + mungbean with two hand weeding at 20 and 40 dae (t5)gave higher tdm than maize + soybean and maize + blackgram association at all the growth stages. the lowest dry matter accumulation was recorded in no weeding in all intercropped situation. 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 25 35 45 55 at harvest r a d ia ti o n i n te rc e p ti o n (% ) days after emergence t1 t2 t3 t4 t5 maize+mungbean 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 20 40 60 80 at harvest r a d ia ti o n i n te rc e p ti o n (% ) days after emergence t1 t6 t7 t8 t9 maize+soybean 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00 25 35 45 55 at harvest r a d ia ti o i n te rc e p ti o n (% ) days after emergence t1 t10 t11 t12 t13 maize +blackgram 142 naher et al. fig. 2. total dry matter of maize under various maize + legumes intercropping systems at different days after emergence during the kharif season of 2012. intercrop legumes with lower density faced different levels of shading from different planting geometry of maize and subsequently accumulated lower dry matter (kephart et al., 1992). the highest dry matter accumulation was observed in sole legumes than intercropped. among all the intercropping systems mungbean gave higher dry matter accumulation than soybean and blackgram at all the growth stages. leaf area index leaf area index (lai) ofmaize was significantly influenced by different legumes intercropping systems and weeding regimes at different days after emergence (fig. 3). it was measured at 25, 35, 45, 55 dae and at harvest of mungbean, blackgram and at 20, 40, 60, 80 dae and at harvest of soybean. lai of maize reached to maximum at 80 dae and then decreased due to leaf senescence. sole maize (t1) produced significantly higher(3.74) lai as compared to all intercropping treatments. 0.00 500.00 1000.00 1500.00 2000.00 2500.00 20 40 60 80 100 t o ta l d ry m a tt e r( g /m 2 ) days after emergence t1 t2 t3 t4 t5 t14 maize+mungbean 0.00 500.00 1000.00 1500.00 2000.00 2500.00 20 40 60 80 100 t o ta l d ry m a tt e r (g /m 2 ) days after emergence t1 t6 t7 t8 t9 t14 maize+soybean 0.00 500.00 1000.00 1500.00 2000.00 2500.00 20 40 60 80 100 t o ta l d ry m a tt e r (g /m 2 ) days after emergene t1 t10 t11 t12 t13 t14 maize+black gram light interception and productivity of maize intercropped 143 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram( weeding at 20 dae), t12= maize + blackgram( weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae),t14 =sole maize (weed free) fig. 3. leaf area index of maize under various maize + legumes intercropping systems at different days after emergence during the kharif season of 2012. similar results had been reported by oljacaet al. (2000) who reported that sole maize produced higher lai values than any other mixtures. lai of maize was higher when it was intercropped with mungbean with two hand weeding (t5) in all the growth stages. it ranged from 1.19 to 3.14 which was followed by maize + soybean (0.93 to 2.56) and maize + blackgram (1.02 to 2.54) intercropping systems. leaf area index was lowest in no weeding intercropping treatment at 20 dae in maize under mungbean, soybean and blackgram combination which were statistically similar than that of other growth stages (fig. 3). thobatsi (2009) also found maize intercropped with cowpea long duration cultivar had significantly higher lai. yield and yield attributes of maize yield and yield contributing characters were influenced significantly by different intercropping systems and weeding regimes (table 2). maximum cob length of maize was found in sole maize (16.8 cm) and maize + mungbean intercropping t5 (16.7 cm). the lowest cob length was obtained from no weeding maize + soybean (15.07 cm) which was as par with t6 (15.13 cm), treatment. higher number of grains cob-1was recorded from weed free sole maize (554) while lower number in no weeding maize + 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 20 40 60 80 100 l e a f a re a i n d e x days after emergence t1 t2 t3 t4 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 20 40 60 80 100 l e a f a re a i n d e x days after emergence t1 t6 t7 t8 t9 t14 0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 20 40 60 80 100 l e a f a re a i n d e x days after emergence t1 t10 t11 t12 t13 t14 maize + blackgram maize + soybean maize + mungbean 144 naher et al. soybean (432) and maize + blackgram (436) intercropping system. among the intercropping systems, maize + mungbean with two hand weedings gave higher grains cob-1 (501) than maize + blackgram and maize + soybean intercropping systems. significant influence was observed in 1000-grain weight by the treatments. the maximum 1000-grain weight was recorded from maize + mungbean with two hand weedings intercropping system (277.5g) which was statistically at par with weed free sole maize (276.9 g), no weeding sole maize (273.7 g), one hand weeding at 20 dae maize + mungbean intercropping plot (272.4g) and maize + blackgram two hand weedings (272 g) treatments. among the intercropping systems, maize + mungbean obtained higher grains weight than maize + blackgram and maize + soybean association. the highest grain yield was obtained from weed free sole maize (8.05 t ha-1) than unneeded sole maize (6.48 t ha-1) treatment (fig. 4). table 2. yield attributes of maize in maize + legumes intercropping system during the kharif season of 2012 treatments cob length (cm) grains cob-1(no.) 1000-grain wt. (g) t1 16.80 ab 486.3 b 273.7 ab t2 15.53 bcd 459.0 bcde 260.5 f t3 15.48 cd 473.0 bcde 272.4 abc t4 15.95 bcd 484.0 bc 268.3 bcde t5 16.67abc 501.0 b 277.5 a t6 15.13 d 432.0 e 263.2 ef t7 15.73 bcd 440.7 cde 269.7 bcd t8 15.97 bcd 473.0 bcde 267.9 bcde t9 15.83 bcd 474.7 bcde 267.1 cde t10 15.07 d 436.0 de 264.4 def t11 15.50 cd 440.0 cde 265.8 def t12 15.92 bcd 471.7 bcde 269.1 bcde t13 15.90 bcd 478.7 bcd 272.0 abc t14 17.70 a 554.0 a 276.9 a cv (%) 4.10 4.88 5.45 the lowest yield was foundin unweeded maize plot in all intercropped situation. among the intercropping situation, maize + mungbean with two hand weedings treatment marked higher grain yield (7.18 t ha-1) than maize + blackgram (6.55 t ha-1) and maize + soybean (6.25 t ha-1) intercropping systems. higher yield of maize observed in monoculture compared to their respective intercropped might be due to no intercrop competition for light, nutrients, moisture and space. this corroborates with the findings of uddin et al. (2003)who reported that maize yield was found to be highest from sole crop when intercropped with legume. the reduction of maize yield was probably due to intercrop competition between crops and weeds. lower crop-weed competition under two hand weedings might have led to better yield components and thus resulted in higher yield (mundra et al., 2003). light interception and productivity of maize intercropped 145 fig. 4. grain yield of maize in maize + legumesintercropping system in kharif season. yield and yield attributes of legumes all the yield characters of legumes were significantly influenced by the treatments of maize + legumes intercropping systems and the results are presented in table 3.higher number of pods plant-1 was recorded in intercropped soybean (80) which was statistically identical with sole soybean (78) and the lowest one was in intercropped mungbean (16.4) that was similar with others mungbean treatments. among the legumes intercropping systems, maize + soybean was found in higher number of pods /plantwith varying weeding regime. akhteruzzaman and quayyum (1991)also reported that number of pods plant-1 of legumes were reduced by intercropping in kharif season. the highest seeds pod-1 was obtained in sole legumes, except mungbean. among the intercropping systems maize + mungbean intercropping in mungbean gave higher number of seeds pod-1 than other maize + soybean and maize + blackgram intercropping (table 4). maximum 1000-seed weight was observed in soybean mono cropping systems which was followed by soybean two hand weedings in intercropping treatments. the lowest 1000-seed weight was observed in blackgram intercropping treatments. seed yield of legumes were influenced by the treatments in kharif season (fig. 5). sole legumes produced the highest seed yield then it reduced significantly when it was grown in association with maize as intercrop. the higher seed yield produced from maize + mungbean intercropping with two hand weedings (572.6 kg ha-1) which was followed by maize + blackgram (510.8 kg ha-1) and maize + soybean (502.9 kg ha-1) intercropping systems. the lowest yield was obtained by mungbean no weeding treatment (302.4 kg ha1) which was statistically similar with maize + blackgram no weeding (316.6 kg /ha) and maize + soybean no weeding (333.7 kg ha-1) treatments. besides, legumes yield was poor due to less availability of light and nutrient in intercropping situation and also shading effect of maize. these findings are in accordance to those of torofderet al. (2006). it also might be due two hand weedings intercropping systems favoured of intercropped mungbean and judicious use of growth resources compared to other intercropped combinations. table 3. yield attributes of legumes in maize + legumes intercropping system during the kharif season of 2012 treatments pods plant-1 (no.) seeds pod-1 (no.) 1000-seed weight (g) t2 16.57 f 12.17 a 36.30 de 0 1 2 3 4 5 6 7 8 9 g ra in y ie ld ( t h a -1 ) treatments 146 naher et al. t3 16.43 f 13.33 a 37.13 cde t4 16.77 f 13.13 a 38.40 cde t5 18.83 f 13.53 a 39.63 bcde t6 52.67 c 2.467 c 31.33 f t7 70.67 b 2.433 c 41.00 bc t8 70.33 b 2.467 c 37.33 cde t9 79.67 a 2.500 c 43.33 ab t10 26.00 e 5.667 b 35.17 ef t11 37.67d 5.667 b 35.27 ef t12 35.43 d 6.000 b 36.07de t13 38.57 d 6.333 b 36.63 cde t15 18.83 f 12.33 a 40.57 bcd t16 78.33 a 2.933 c 46.00 a t17 47.67 c 6.667 b 39.27 bcde cv (%) 8.97 10.47 6.16 fig. 5. seed yield of legumes in maize legumes intercropping system in kharif season. evaluation of intercrop productivity intercrop productivity was evaluated by equivalent yield and monetary advantage (table4). the maximum maize equivalent yield (12.49t ha-1) was obtained from t5 treatmentin both intercrop and sole situation. the lowest maize equivalent yield (6.48 t ha-1) was obtained from no weeding regime of sole maize.patraet al. (2000)also reported similar observations in different intercropping systems.the results showed that the total gross return was higher in all the intercropping systems compared to their respective sole crop. the highest total gross return of tk. 124900ha-1was obtained from maize + mungbean intercropping with two hand weedings situation. on the other hand, the lowest gross return of tk. 50643 ha-1was found from sole situation in mungbean treatment. the cost of cultivation increased in the intercropping systems compared with the respective sole crop of maize and legumes. it might be due to increased seed requirement and additional cultural practices for legumes in the intercropping systems. similar results were also reported by patel and rajagopal (2001) under cereal + legume intercropping system.the highest cost of cultivation was observed in maize + soybean (tk. 45035 ha-1) intercropping systems. the lowest cost of cultivation was tk. 30515 ha-1 from sole 0 200 400 600 800 1000 1200 s e e d y ie ld ( k g h a -1 ) treatments light interception and productivity of maize intercropped 147 mungbean. the cost of cultivation increased in the intercropping system over the respective sole crops of legumes due to addition of another crop in this system. the highest bcr (benefit cost ratio) was observed from same treatment of the maize + mungbean with two hand weedings situation (2.84). sole maize with no weeding treatment gave lower bcr than other intercropping systems (1.60). table 4. equivalent yield andeconomic analysis of maize + legume intercropping systems at different weeding regimes during the kharif season of 2012 treatments maize equivalent yield (t ha-1) gross return (tk. ha-1) cost of cultivation (tk. ha-1) bcr t1 6.48 64800 40515 1.60 t2 7.93 79300 41715 1.90 t3 9.77 97700 43215 2.26 t4 9.98 99800 43215 2.31 t5 12.49 124900 44000 2.84 t6 8.14 81400 41034 1.98 t7 8.80 88000 42535 2.07 t8 9.76 97600 42535 2.29 t9 10.81 108100 45035 2.40 t10 8.00 80000 41115 1.95 t11 10.21 102100 42615 2.40 t12 10.76 107600 42615 2.52 t13 10.22 102200 43015 2.38 t14 8.05 82308 44675 1.84 t15 0.818 50643 30515 1.66 t16 0.982 65669 32785 2.00 t17 1.05 64322 30555 2.11 t1= sole maize (no weeding), t2= maize + mungbean (no weeding), t3= maize + mungbean (weeding at 20 dae), t4= maize + mungbean (weeding at 40 dae), t5= maize + mungbean (weeding at 20 and 40 dae), t6= maize + soybean (no weeding), t7= maize + soybean (weeding at 20 dae), t8= maize + soybean (weeding at 40 dae), t9= maize + soybean (weeding at 20 and 40 dae), t10= maize + blackgram (no weeding), t11= maize + blackgram( weeding at 20 dae), t12= maize + blackgram( weeding at 40 dae), t13= maize + blackgram (weeding at 20 and 40 dae),t14 =sole maize (weed free), t15=sole mungbean (weed free) , t16=sole soybean (weed free) and t17= sole blackgram (weed free) conclusion the results revealed that intercropping of two rows of mungbean in between two rows of maize with two hand weeding at 20 and 40 dae appeared as a profitable practice for good yield advantages, optimum use of par, weed control efficiencies, and monetary values. references ahmed, f., m.n. islam, m.t. rahman, m.a. jahan and m.s.a. khan. 2010. leaf area index, radiation interception, dry matter production and grain yield of hybrid maize as influenced by plant spacing. bangladesh agron. j.13 (1 & 2):51-58. akhteruzzaman, m. and m.a.quayyum.1991. intercropping of maize with three varieties of groundnut at two levels of plant population. bangladesh j. agril. sci.18(1): 39-44. alom, m.s., n.k. paul and m.a. quayyum. 2010. production potential of different varieties of hybrid maize (zea mays l.) with groundnut (arachishypogaea l.) under intercropping system. bangladesh j. agril. res. 35(1): 51-64. 148 naher et al. bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. ph. d. dissertation, indian agricultural research institute, new delhi. banik, p., a.midya, b.k.sarkar and s.s. ghose. 2006. wheat and chickpea intercropping systems in an additive experiment. advantages and weed smothering. european j.agron.24:325-328. bbs. 2017. yearbook of agricultural statistics of bangladesh-2018.bangladesh bureau of statistics. ministry of planning. govt. of the peoples’ republic of bangladesh. pp.73-110. baumann, d.t., m.j. kropf and l. bastiaans. 2000. intercropping leeks to suppress weeds. weed res. 40: 361-376. cruz, f.d., k.moody and m.b.d. ramas. 1986. reducing variability sampling weeds in upland rice(oryza sativa). philopp j. weed sci.13: 56-59. dogan, m.n., a. unay, o. boz and f. albay. 2004. determination of optimum weed control timing in maize (zeamays l.). turkish j. agron., 28: 349-354. dwivedi, s.k. and g.k. shrivastava. 2011. planting geometry and weed management for maize (zea mays) – blackgram (vignamungo) intercropping system under rainfedvertisols. indian j. agron.56(3): 202-208. eskandari, h. 2012. intercropping of maize (zea mays) with cowpea (vignasinensis) and mungbean (vignaradiata): effect of complementarity of intercrop components on resource consumption, dry matter production and legumes forage quality. j. basic. appl. sci. res. 2(1): 355-360. gao, y., a. duan, x. qiu, j. sun, j. zhang, h. liu and h. wang. 2010. distribution and use efficiency of photosynthetically active radiation in strip intercropping of maize and soybean. agron.j. 102(4): 1149–1157. gharineh, m.h. and s.a.moosavi. 2010. effects of intercropping (canola-fababean) on density and diversity of weeds. notulae sci. biol. 2(4):109-112. kadziuliene, z., l. sarunaite, i. dereikyte, s. maiksteniene, a. arlauskiene, l. masilionyte, r. cenuleviciene and v. zekaite. 2009. qualitative effects of pea and spring cereals intercrop in the organic farming systems. agron. res.7(2):606-611. katsaruware, r.d. and i.o. manyanhaire. 2009. maize-cowpea intercropping and weed suppression in leaf stripped and detasselled maize in zimbabwe. j. environ. agric food chem. 8(1): 1218-1226. keating, b.a. and p.s. carberry. 1993. resource capture and use in intercropping: solar radiation.field crops res.34: 273-301. kephart, k.d., d.r. buxton and s.e. taylor. 1992. growth of c3 and c4 perennial grasses in reduced irradiance. crop sci.32: 1033-1038. li, l.s., j. zhang, x.f. li, s.yang and z. rengel.2001. wheat/maize or wheat/ soybean strip intercropping yield advantage and interspecific interaction on nutrients. field crops res. 71: 123-137. liu, b., x.b. liu, c.wang,j. jin, s.j. harbert and m. hashemi. 2010. response of soybean yield and yield components to light enrichment and planting density. int. j. plant prod.4(1): 1-10. mundra, s.l., a.k.vyas and p.l.maliwal. 2003. effect of weedand nutrient management on weedgrowth and productivityof maize(zea mays l.). indian j. weed sci. 35(1&2):57-61. muoneke, c.o., m.a.o.ogwuche and b.a. kalu. 2007. effect of maize planting density on the performance of maize/soybean intercropping system in a guinea savannah agro-ecosystem. african j. agril. res.2(12):667-677. oijaca, s., r. cvetkovic, d. kovacevic, g. vsiii and n. momirovic. 2000. effect of plant arrangement pattern and irrigation on efficiency of maize and bean intercropping system. j. agric. sci.135: 261270. pandey, a.k. andv.prakash. 2002. weed management in maize and soybean intercropping system.indian j.weed sci.34(1&2): 58−62. patel, j.r. and s. rajagopal. 2001. production potential of forage maize (zea mays l.) with legumes under intercropping systems. indian j. agron.46(2):211-215. light interception and productivity of maize intercropped 149 patra, b.c., b.k. mandal and a.l. padhi. 2000. production potential of winter maize (zea mays l.) based intercropping systems. indian j. agril. sci.70(4):203-206. poggio, s.l. 2005. structure of weed communities occurring in monoculture and intercropping of field pea and barley. j. agric. ecosys. environ.109:48-58. quayyum, m.a. and a.f.m. maniruzzaman. 1995. effect of maize (zea mays l.) and rice (oryza sativa) with blackgram (phaseolusmungo). indian j. agron. 40(1): 20-25. s. maitra, d.c. ghosh, g.sounda, p.k. jana and d.k. roy.2000.productivity, competition and economics of intercropping legumes in finger millet (eleusinecoracana) at different fertility levels.indian j. agric. sci.70(12):824-828. talukder, a.s.m.h.m., m.a. sufian, c.a. meisner, j.m. duxbury, j.g. lauren and a.b.s. hossain. 2003. rice, wheat and mungbean yields in response to n levels and management under a bed planting systems. bangladesh j. ghurpukur, shatkhira.5:44-48. thobatsi, t. 2009. growth and yield responses of maize (zea mays l.) and cowpea (vignaunguiculatal.) in an intercropping system. msc. thesis. university of pretoria. 159p. torofder, g.s., a.ahmed,m.m. alam and m.a. quayyum. 1992. intercropping of maize with different legume. bangladesh j. life sci. 4(2): 33-37. trenbath, b.r. 1986. resource use by intercrops. in: ca francis (ed), multiple cropping systems. macmillan pub. co.866 third avenue, new york 10022. pp.57-81. uddin, m.s., m.j.rahman, s.a. begum and m.r. ali. 2003. intercropping of maize with soybean in saline area under rainfed condition. bangladesh j. agril. res. 28(3): 451-455. light interception and productivity of maize intercropped with legumes in kharif season bangladesh agron. j. 2024, 27(1): 19-22 influence of date of transplanting on the yield performance of salt tolerant rice varieties during boro season t. akter agronomy division, bangladesh rice research institute, gazipur corresponding author, email: tahminatanni.ag@gmail.com (received: 03 november 2024, accepted: 31 march 2025) keywords: dry-season boro rice, salt-tolerant rice varieties, transplanting date optimization, coastal region agriculture abstract future food security in bangladesh relies heavily on effective adaptation strategies for dryseason boro rice production in coastal regions. this study focused on yield performance by evaluating the different transplanting dates as an adaptation approach for dry-season boro rice. an experiment was conducted in kamargati village, kaliganj upazila under satkhira district to assess the effect of rice variety, transplanting date, and their interaction on the yield performance of salt-tolerant boro rice during december 2023 to february 2024. the study included three varieties: brri dhan67, brri dhan97, and brri dhan99, with five transplanting dates: 15th december, 30th december, 15th january, 30th january, and 15th february. the experiment followed a split-plot design with three replications. results showed that var. brri dhan67 yielded the highest grain (5.58 t ha−1) when transplanted on 15th december. in the transplanting from 15th to 30th december, brri dhan99 outperformed brri dhan97 in terms of yield. however, after 15th january, increasing soil and water salinity led to crop damage, resulting in no yield. the challenge of early transplantation arises due to the prevalence of t. aman rice in the area, while late transplanting faces difficulties from increasing salinity in soil and water. the results indicate significant differences in yield based on the variety and planting date, with var. brri dhan67 consistently producing higher yields in early stages. introduction rice (oryza sativa) is a crucial staple crop, feeding billions of people worldwide. the boro season, or winter rice, is one of the most important for attaining high yields in bangladesh (uddin, 1993; sikder et al., 2021). to mitigate the challenges posed by saline conditions, salttolerant rice varieties have been developed, showing promise for sustaining rice production in affected regions (thirumeni et al., 2024). transplanting time is crucial in the boro season as it significantly affects yield performance. delayed transplanting may expose the crop to lower temperatures and shorter day lengths, which can negatively impact flowering, grain filling, and yield as a whole (khan et al., 2022). because of the high salinity levels, bangladesh's boro season salt-tolerant rice varieties still show yield variability depending on transplanted time (islam et al., 2021). alam et al. 2020 showed that by avoiding the crucial reproductive stage during periods of high salinity, early transplanting in december enabled salt-tolerant cultivars to yield more. in saline-affected areas, yield and water productivity can also be increased by modifying the dates of planting and utilizing salt-tolerant rice cultivars (sarangi et al., 2021). farmers can optimize planting schedules to enhance production and minimize crop loss by conducting research on salt-tolerant rice cultivars under different transplanting dates. it is 20 akter possible to improve the management of rice production in vulnerable areas in order to ensure both food security and economic stability by knowing how transplanting date affects yield, especially in saline are. in order to determine the best time to plant in saline-prone salt-tolerant rice cultivars in boro season under various transplanting dates was done. materials and methods experimental site the experiment was conducted at farmer’s field in kamargati village under the kaliganj upazila of satkhira (aez 13, ganges tidal floodplain) during boro season from december 2023 to may 2024. experimental details the study consisted of three brri salt tolerant varieties viz, brri dhan67, brri dhan97 and brri dhan99 with five transplanting dates: 15th december, 30th december, 15th january, 30th january, and 15th february. the experiment was laid out in a split-plot design with three replications. forty-five days old seedlings were transplanted in 5 m × 5 m rows using 2-3 seedlings hill−1 maintaining spacing of 20 cm × 20 cm. fertilizer and cultural practices were followed as per brri recommendations. data collection and analysis the crops were harvested at different dates because of variety and different date of transplanting. the maturity of crops was determined at the time when 90% of the grains became golden yellow in colour. then the harvested crops of each plot and variety were bundled separately, properly tagged and brought to the threshing floor. grains were separated from the plants by pedal thresher. the grains then were cleaned, weighed and dried in the sun. then the grain moisture content was adjusted to 14% moisture content. finally grain yields unit−1 area were converted to t ha−1. data were collected on yield and yield attributes and mean difference were compared by least significant difference (lsd) test. results and discussion effect of transplanting dates on grain yield the results showed that a significant variation in yield across transplanting dates and rice varieties, emphasizing the importance of optimal planting time for maximizing yield. rice var. brri dhan67 showed the maximum yields of 5.58 and 5.13 t ha−1 when transplanted on december 15 followed by december 30. however, yield dropped sharply to 2.83 t ha−1 by mid-january and reached zero by january 30. brri dhan97 showed consistently lower yields across all dates, with a peak yield of 3.54 t ha−1 on december 15, followed by a gradual decline to 3.33 t ha−1 by december 30, and further reductions in january. brri dhan99 exhibited moderate performance, at 4.12 t ha−1 on december 15, decreasing steadily to 1.91 t ha−1 by january 15, and ceasing production in late january. influence of date of transplanting on the yield performance of salt tolerant rice varieties 21 fig. 1. yield (t ha−1) of different varieties over time the fig. 1 showed that all varieties marked decline in yield over time, reaching zero by late january. salam et al. (2019) identified brri dhan67 as a high-yielding variety in salineaffected areas, corroborating its peak performance in this study. however, delays in transplanting expose crops to adverse environmental conditions, such as increased salinity and temperature fluctuations, leading to reduced yields. effect of environmental conditions on yield rising soil and water salinity from january to april had a negative impact on rice yields (fig. 2). fig. 2. salinity data brri dhan67, recognized as salinity tolerance (islam & gregorio, 2013; salam et al., 2019), performed best under optimal conditions but suffered yield reductions under increased 0.00 1.00 2.00 3.00 4.00 5.00 6.00 y ie ld ( t h a − 1 ) brri dhan67 brri dhan97 brri dhan99 0 2 4 6 8 10 12 14 16 18 20 1 5 -d e c2 3 2 2 -d e c2 3 2 9 -d e c2 3 5 -j a n -2 4 1 2 -j a n -2 4 1 9 -j a n -2 4 2 6 -j a n -2 4 2 -f e b -2 4 9 -f e b -2 4 1 6 -f e b -2 4 2 3 -f e b -2 4 1 -m a r2 4 8 -m a r2 4 1 5 -m a r2 4 2 2 -m a r2 4 2 9 -m a r2 4 5 -a p r2 4 1 2 -a p r2 4 1 9 -a p r2 4 s a lin it y d a ta ( d s m − 1 ) salinity data (ds/m) linear (salinity data (ds/m)) 22 akter salinity stress in january. the reduced yields of brri dhan97 after december 30 may also reflect its sensitivity to temperature fluctuations, as noted by najeeb et al. (2021). conclusion the results showed the critical importance of transplanting dates in maximizing rice yield under saline conditions. the optimal transplanting boro rice was identified as december 15–30, with yields declining significantly beyond this period. rice var. brri dhan67 identified the most promising variety for saline-prone areas, while brri dhan97 and brri dhan99 require further evaluation to enhance performance under sub-optimal planting conditions. however, this study's limitation to a single location highlights the need for broader research to account for varying environmental factors across different regions. future studies should include more varieties and locations to better understand yield performance across different environments. references alam, a., h. ullah, a. attia, and a. datta. 2020. effects of salinity stress on growth, mineral nutrient accumulation and biochemical parameters of seedlings of three citrus rootstocks. int. j. fruit sci. 20(40): 786-804. islam, m.a., v. shelia, f. ludwig, l.l. de bruyn, m.h. rahman and g. hoogenboom. 2021. bringing farmers’ perceptions into science and policy: understanding salinity tolerance of rice in southwestern bangladesh under climate change. land use policy. 101 (october): 105159. islam, m.r. and g.b. gregorio. 2013. progress of salinity tolerant rice variety development in bangladesh. sabrao j. breed.genet. 45(1): 21–30. khan, m.n.a., m.b. hossain, p.k. biswas, a.r. amin and a. rahman. 2022. influence of transplanting date on performance of boro rice varieties in lalmai-hill area. saarc j. agric. 20(1): 143–155. najeeb, s., a. mahender, a. anandan, w. hussain, z. li and j. ali. 2021. genetics and breeding of lowtemperature stress tolerance in rice. in: ali, j., s.h. wani. (eds) rice improvement. springer, cham. salam, m.t.b., b. karmakar, s.m.t. hossain, m.h. robin, m.z. mariam, and m. hossain. 2019. agronomic performance of modern rice varieties in southwest bangladesh. plant sci. today. 6(4): 528–532. sarangi, s.k., m. mainuddin, b. maji, k.k. mahanta, s. digar, d. burman, u.k. mandal and s. mandal. 2021. optimum sowing date and salt tolerant variety boost rice (oryza sativa l.) yield and water productivity during boro season in the ganges delta. agron. 11(12): 2413. sarwar, a.k.m.g. and s.c. chanda. 2020. growth and yield descriptors of rice influenced by transplanting date. j. agric. food environ. 1(4): 48–52. sikder, m.k.i., s.g. kim, m.j. alam, m.m. hoque and m.m. hassan. 2021. production and acreage growth and seasonality in rice in bangladesh. asian j. agric. ext., econ. sociol. 39(3): 1–14. thirumeni, s., k. paramasivam and m. subramanian. 2024. breeding salt-tolerant rice varieties in puducherry (u. t.). in: singh, r.k., m. prakash, r.k. gautam, s.l. krishnamurthy, s. thirumeni. (eds) genetic improvement of rice for salt tolerance. springer, singapore. uddin, m.n. 1993. rice in bangladesh. jircas international symposium series, 2(1), 31–41. bangladesh agron. j. 2022, 25(1): 105-113 response of biochar on growth and yield of aman rice under salt stress m.m. khanam, n. nawal, m. hasanuzzaman, m.f. karim and a. rahman* department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding e-mail: anisur68@yahoo.com (received: 08 june 2022, accepted: 11 august 2022) keywords: salinity, biochar, aman rice, brri dhan62, rice yield abstract a pot experiment was conducted in sher-e-bangla agricultural university, dhaka, bangladesh during aman season, 2018 to assess the effect of biochar on rice (brri dhan62) under salt stress conditions. the factorial experiment was laid out in randomized complete block design (rcbd) with four replications. three levels of salinity were used viz. control (s0), 1600 ppm nacl (s1), and 2800 ppm nacl (s2) under factor a and four levels of biochar were applied viz. 0 t ha−1 (b0), 2 t ha−1 (b1), 4 t ha−1 (b2) and 6 t ha−1 (b3) under factor b. the salt materials were added on pot in two installments at 20 and 30 days after transplanting (dat). exposure to salinity decreased growth and yield of rice including plant height, tillers hill-1, effective tillers hill-1, grains panicle-1, 1000-grain weight, grain yield and straw yield. the magnitude of growth and yield reduction increased with increasing the salinity level. exposure of 1600 ppm and 2800 ppm nacl declined the grain yield of rice by 28 and 100%, respectively. straw yield (18 and 100%, respectively) and other yield contributing parameters declined by these two levels of salinity in the same way. application of different levels of biochar ameliorated saltinduced damages to a certain extent. under 2800 ppm nacl stress, application of biochar extended life duration of rice plant upto 80 dat, whereas without biochar application rice plant died after 60 dat. upon exposure to 1600 ppm nacl stress, application of 2, 4 and 6 t ha−1 of biochar increased grain yield by 37, 42 and 30%, respectively, compared with the respective salt treatments (without biochar). biochar enhanced yield of rice under saline conditions by enhancing yield contributing attributes including effective tillers and 1000-grain weight and by reducing salt-induced damages. however, response of 4 t ha−1 of biochar was best among the biochar levels (2, 4 and 6 t ha−1 of biochar) under both saline and non-saline conditions. introduction rice is the second most widely grown cereal and primary source of food for more than half of the world population (haque et al., 2015). it is adapted to a variety of climatic conditions. but continuous climate change induced various environmental stresses on plants including salinity, drought, heat, cold etc. among the environmental factors, salinity is one of the detrimental abiotic stresses reducing crop growth and productivity (rahman et al., 2017). around 20% of world irrigated land are salt affected (munns and tester, 2008) and it is assumed that 50% of world cultivable land will be affected by salinity by 2050 (mahajan and tuteja, 2005). however, salinity is a major environmental threat for crop production as its negative effect starts from germination and exist till death of plant (mahajan and tuteja, 2005; mishra et al., 2013). salinity in the plant root region creates osmotic, ionic and oxidative stress in plants (munns and tester, 2008; hussain et al., 2017) which ultimately reduced growth and yield of plant (hasanuzzaman et al., 2013; rahman et al., 2016a; rahman et al., 2016b). salt induced stress reduced plant height, tiller number, effective tillers, filled grain, grain yield, straw yield even causes death of plant (hasanuzzaman et al., 2013; islam et al., 2022). mailto:anisur68@yahoo.com 106 khanam et al. biochar is carbon rich fine-grained charcoal produced by pyrolysis of biomass in a low oxygen environment and it increase soil fertility (liu et al., 2016; zhang et al., 2019). biochar improves physical, chemical and biological properties of soil by increasing soil organic carbon, cation exchange capacity and stabilization of soil structure (zheng et al., 2018). chaganti and crohn (2015) revealed that biochar application under salt stress conditions reduces salt-induced damages by reducing na+ uptake and increasing nutrient uptake. biochar application decreased bulk density, electrical conductivity, exchangeable na+ and exchangeable clin soil under salt stress conditions that helps to mitigate salinity stress in rice (zhang et al., 2019). however, yang et al. (2021) revealed that application of 10 t ha–1 of biochar increased tropical rice production by improving soil physical properties and at the same time increased soil salinity. application of biochar in higher rate (>10 t ha–1) decreased growth and yield of rice (chen et al., 2021 and yang et al., 2021). considering the issues discussed, the present study was conducted to identify the lower rate of biochar which can play positive role on rice under salt stress conditions. materials and methods the experiment was conducted at sher-e-bangla agricultural university, dhaka, bangladesh during aman season (july to december) 2018 in net house conditions on plastic pot (14 inches diameter and 18 inches depth). the experimental pots were filled with 12 kg well dried and fertilized soil. urea, tsp, mop and gypsum fertilizers were applied at the rate of 150, 50, 80 and 60 kg ha−1 as per recommendation of bangladesh rice research institute (brri). four levels of biochar were applied on plastic pot as per treatment. after growing in seedbed, 25 days old seedlings were transplanted in experimental pot. two seedlings were transplanted in each hill and three hills set in each pot. different intercultural operations were done as per requirement of the crop. after establishment of seedlings, three levels of nacl were added on pot in two equal installments at 20 and 30 dat. the experiment was laid out in randomized complete block design (rcbd) with four replications. three levels of salinity viz. control (s0), 1600 ppm nacl (s1), and 2800 ppm nacl (s2) were under factor a and four levels of biochar viz. 0 t ha−1 (b0), 2 t ha−1 (b1), 4 t ha−1 (b2) and 6 t ha−1 (b3) were under factor b. all plants from each pot were considered for different growth, yield and yield contributing parameters like plant height, tiller hill-1, effective tillers hill-1, grains panicle-1, 1000-grain weight, grain yield and straw yield. the collected data analyzed by statistix 10 software by following two-way anova model and mean separation was done by least significant difference (lsd) test at the 5% level of significance. results and discussion plant height salinity significantly influenced plant height of rice (table 1). in response to 1600 ppm nacl stress, rice plant showed statistically similar plant height compared with control. upon exposure to 2800 ppm nacl, the plant height of rice declined by 19, 48, 71 and 100% at 40, 60 and 80 dat, and at harvest, respectively, compared with untreated control. our results in agreement with islam et al. (2022) who stated that salinity decreased plant height of rice and magnitude of decreases increased with the advancement of the growth period. under saline conditions, na+ enter into shoot of rice through apoplastic pathway which disrupts cell division and cell elongation and ultimately reduced growth of rice (hussain et al., 2017). biochar application had significant influence on plant height of rice upto 40 dat (table 1). at 20 dat, the longest plant recorded for the application of 4 t ha−1 of biochar. application of 2 and 6 t ha−1 of biochar had no impact on plant height compared with control at 20 dat. at 40 dat, the longest plant recorded for the application of 6 t ha−1 of biochar. biochar application influenced plant height of rice under salt stress conditions (table 1). upon exposure to 1600 ppm nacl, all treatment combinations showed statistically similar plant height. under 2800 ppm nacl stress conditions, rice plant survived upto 60 dat without biochar application, response of biochar on growth and yield of aman rice 107 whereas rice plant survived upto 80 dat when combined with biochar application. upon exposure to 2800 ppm nacl, plant height increased by 56, 68 and 76%, respectively at 60 dat for the application of 2, 4 and 6 t ha−1 of biochar. table 1. effect of nacl and biochar on plant height of aman rice (brri dhan62) treatments plant height (cm) 20 dat 40 dat 60 dat 80 dat at harvest effect of nacl s0 45.36 63.64 a 87.17 a 87.96 a 86.8 a s1 45.278 62.06 a 79.35 a 86.67 a 85.99 a s2 45.22 51.36 b 45.45 b 25.34 b 0 b lsd(0.05) ns 3.63 14.68 12.49 4.73 cv (%) 7.07 8.54 28.88 26.05 11.43 effect of biochar b0 45.24 ab 56.42 b 64.789 57.05 b 58.691 b1 43.47 b 56.64 b 71.237 69.99 ab 57.762 b2 46.597 a 59.73 ab 72.649 75.99 a 59.118 b3 45.833 ab 63.28 a 73.948 63.59 ab 54.824 lsd(0.05) 2.66 4.19 ns ns ns cv (%) 7.07 8.54 28.88 26.05 11.43 combined effect of nacl and biochar s0b0 44.27 a-c 61.25 bc 87.21 a 87 a 86.74 a s0b1 45.85 ab 63.43 a-c 85.52 a 87.42 a 87.26 a s0b2 48.28 a 68.11 ab 88.09 a 91.50 a 89.67 a s0b3 42.49 bc 61.78 bc 87.86 a 85.92 a 83.53 a s1b0 45.53 ab 58.85 c 76.85 a-c 84.15 a 89.33 a s1b1 43.74 a-c 56.96 c 80.90 ab 89.32 a 86.03 a s1b2 44.74 a-c 63.38 a-c 78.98 a-c 86.10 a 87.69 a s1b3 47.44 a 69.05 a 80.66 ab 87.12 a 80.95 a s2b0 45.93 ab 49.17 d 30.31 d 0 e 0 b s2b1 40.83 c 49.54 d 47.29 d 33.25 bc 0 b s2b2 46.78 ab 47.72 d 50.88 cd 50.38 b 0 b s2b3 47.58 a 59.03 c 53.33 b-d 17.75 cd 0 b lsd(0.05) 4.61 7.25 29.31 24.98 9.47 cv (%) 7.07 8.54 28.88 26.05 11.43 here, s0= 0 ppm nacl s1= 160 ppm nacl s2= 280 ppm nacl b0= 0 t ha−1 biochar b1=2 t ha−1 biochar b2= 4 t ha−1 biochar b0= 6 t ha−1 biochar ns= non significant tillers hill−1 exposure to nacl stress declined the tillers hill−1 in entire life of rice except 20 dat (table 2). at 40 dat, application of 1600 and 2800 ppm nacl declined the tillers hill−1 of rice by 11% and 46 %, respectively, compared with control. upon exposure to 1600 and 2800 ppm nacl, the tillers hill−1 of rice declined at 60 dat (12% and 76%, respectively), 80 dat (8% and 86%, respectively) and at harvest (11% and 100%, respectively) in the same way. the present study revealed that the magnitude of tiller decreasing trend increased with the advancement of the growth period and increment of the salinity level. the immediate response of salinity to plant is osmotic and ionic stress which reduces cell elongation, cell division, stomatal closure and leaf area as well as photosynthesis, plant height and tiller number (rahman et al., 2017). the number of tillers hill−1 of rice enhanced by different levels of biochar application (2, 4 and 6 t ha−1) at 20 dat, 80 dat and at harvest (table 2). at 40 and 60 dat, biochar had no impact on tiller production or on mortality. 108 khanam et al. interaction effect of biochar and salinity had significant impact on tiller production at 60 dat, 80 dat and at harvest (table 2). under controlled conditions, biochar treated plant produced statistically similar number of tiller hill-1 throughout the growth period of rice. in response to 2800 ppm nacl, all tillers of rice plant died without biochar application at 80 dat whereas few tillers remained alive for the application of 2, 4 and 6 t ha−1 of biochar. at harvesting time, no tiller remained alive in response to 2800 ppm nacl irrespective of biochar levels. table 2. effect of nacl and biochar on number of tiller hill−1 of aman rice (brri dhan62) treatments tiller hill−1 (no.) 20 dat 40 dat 60 dat 80 dat at harvest effect of salt s0 5.1913 12.12 a 12.49 a 11.18 a 10.41 a s1 5.3856 10.83 b 10.94 a 10.32 a 9.29 b s2 5.3437 6.59 c 2.94 b 1.53 b 0 c lsd(0.05) ns 1 1.57 1.15 0.7 cv (%) 15.13 14.15 24.84 20.76 14.75 effect of biochar b0 4.57 b 9.08 7.9133 6.13 c 5.63 b b1 5.35 a 9.96 8.6975 8.26 ab 6.97 a b2 5.41 a 10.47 9.5333 8.88 a 7.05 a b3 5.90 a 9.89 9.0167 7.44 bc 6.60 a lsd(0.05) 0.67 ns ns 1.32 0.8 cv (%) 15.13 14.15 24.84 20.76 14.75 combined effect of salt and biochar s0b0 4.51 12.25 12.97 a 10.31 ab 9.65 ab s0b1 5.19 12 12.28 ab 11.49 a 10.72 a s0b2 5.22 13 13.15 a 11.38 a 10.70 a s0b3 5.85 11.25 11.58 ab 11.56 a 10.56 ab s1b0 4.70 9.63 c 9.40 b 8.08 b 7.25 c s1b1 5.70 11.47 11.32 ab 11.55 a 10.2 ab s1b2 5.38 11.40 12.05 ab 11.90 a 10.45 ab s1b3 5.77 10.83 10.98 ab 9.750 ab 9.25 b s2b0 4.50 5.38 1.38 c 0 d 0 d s2b1 5.15 6.40 2.50 c 1.75 cd 0 d s2b2 5.65 7 3.40 c 3.38 c 0 d s2b3 6.08 7.59 4.50 c 1 d 0 lsd(0.05) ns ns 3.14 2.29 1.39 cv (%) 15.13 14.15 24.84 20.76 14.75 effective tillers hill−1 application of nacl in brri dhan62 decreased the number of effective tillers hill−1 to a great extent (table 3). increase in salinity strength proportionally decreased the number of effective tillers hill−1 in rice. exposure to 1600 and 2800 ppm nacl decreased the number of effective tillers hill−1 by 19 and 100%, respectively, compared with control (table 3). our results in line with hussain et al. (2017) who reported that salinity delayed flowering and even arrest panicle initiation by decreasing nutrient uptake, photosynthesis and ultimately reduced productive tillers. the number of effective tiller hill−1 of rice was influenced by different levels of biochar application (table 3). the present study revealed that the number of effective tillers hill−1 of brri dhan62 here, s0= 0 ppm nacl s1= 160 ppm nacl s2= 280 ppm nacl b0= 0 t ha−1 biochar b1=2 t ha−1 biochar b2= 4 t ha−1 biochar b0= 6 t ha−1 biochar ns= non significant response of biochar on growth and yield of aman rice 109 increased by 16 and 20% by the application of 2 and 4 t ha−1 of biochar, respectively. the present finding corroborates with sriphirom et al. (2020) who reported that biochar application increases productive tiller and yield by increasing nutrient uptake efficiency. however, compared with control, application of 6 t ha−1 of biochar showed no impact on productive tiller production. combined application of nacl and biochar showed significant effect on the number of effective tillers hill−1 of rice. the highest number of effective tiller hill−1 (9.33) recorded for the application of 4 t ha−1 of biochar under controlled condition (0 ppm nacl). at 1600 ppm nacl stress, application of 2, 4 and 6 t ha−1 of biochar increased the effective tillers hill−1 of brri dhan62 by 41, 48 and 22%, respectively, compared with salt-treated alone (table 3). exposure to 2800 ppm nacl stress, brri dhan62 failed to produce productive tillers in absence or presence of any doses of biochar. filled grains panicle−1 treatment of rice plant with 1600 and 2800 ppm nacl decreased the number of filled grains panicle−1 by 15 and 100%, respectively, compared with untreated control (table 3). the reduction of the filled grains panicle−1 was 100% under severe salinity as there was no plant alive and effective tiller production under this treatment. this result is in line with nahar et al. (2009) who reported that increase in salinity decreased the number of filled grains panicle−1. the number of filled grains panicle−1 varied significantly for the application of different levels of biochar (table 3). compared with control, application of 2 and 4 t ha−1 of biochar increased the filled grains panicle−1 by 9 and 10 %, respectively. chen et al. (2021) reported that biochar application increased the number of productive tillers, number of filled grain and grain yield of rice. addition of 6 t ha−1 of biochar showed similar result compared with control. interaction effect of nacl treatment and biochar application had significant impact on the production of filled grains panicle−1 (table 3). under controlled condition, application of 2 and 4 t ha−1 of biochar showed no impact on the production of filled grains panicle−1. application of 6 t ha−1 of biochar slightly decreased the number of filled grains panicle−1. however, in 1600 ppm nacl treated rice plant, the production of the filled grains panicle−1 enhanced by 22, 28 and 20% for the application of 2, 4 and 6 t ha−1 of biochar, respectively, compared with salt treated plant alone. upon exposure to 2800 ppm nacl stress, brri dhan62 failed to produce filled grain in absence or presence of any doses of biochar. total grains panicle−1 imposition of 1600 and 2800 ppm nacl decreased the number of total grains panicle−1 in rice by 26 and 100%, respectively, compared with untreated control (table 3). imposition of 2800 ppm nacl caused death of all plant at harvesting time as a result reduction of total grains panicle−1 was 100% under this treatment. these results were in line with previous studies (nahar et al., 2009; islam et al., 2022) who reported that salinity decreases number of grains in rice. the number of total grains panicle−1 showed positive relation with biochar application in brri dhan62 (table 3). when rice plants were exposed to 2, 4 and 6 t ha−1 of biochar, the production of the total grains’ panicle-1 uplift by 21, 27 and 10%, respectively, compared with control. the combination of different levels of salinity and biochar showed significant effect on the production of total grains panicle−1 (table 3). in untreated control conditions, application of different levels of biochar, statistically produced similar number of total grains panicle−1. when rice plants were exposed to 1600 ppm nacl with the application of 2, 4 and 6 t ha−1 of biochar, the total grains panicle−1 enhanced by 52, 64 and 33%, respectively, compared with 0 t ha−1 of biochar. in 2800 ppm nacl stressed-plant, application of any dose of biochar failed to produce any number of grains in brri dhan62 as all plants died under this treatment. thousand grains weight 110 khanam et al. upon exposure to 1600 ppm nacl, 1000-grain weight reductions were insignificant compared with control (table 3). application of 2800 ppm nacl caused death of all plant before harvesting time. as a result, reduction of 1000-grain weight was 100% compared with untreated control. different levels of biochar application had non-significant influence on 1000-grain weight of brri dhan62. the interaction effect of nacl and biochar had significant influence on 1000-grain weight of rice (table 3). under controlled conditions, application of different level of biochar showed no variation on 1000-grain weight of rice. in 1600 ppm nacl-treated rice plant, application of different levels of biochar uplift 1000-grain weight and showed statistically similar results. exposure of 2800 ppm nacl caused death of all rice plant in all biochar treated rice plant. grain yield exposure to 1600 and 2800 ppm nacl decreased grain yield by 28 and 100%, respectively, compared with control (table 3). salinity reduced grain yield in rice by decreasing yield attributes including effective tillers, number of grain and 1000-grain weight (islam et al., 2022). the present study revealed that salinity decreased grain yield by decreasing the number of effective tiller hill−1, total grains and filled panicle−1 which is in line with previous studies (zeng et al., 2002; islam et al., 2022). application of biochar increased grain yield of rice by promoting nutrient uptake (liu et al., 2016). yang et al. (2021) stated that biochar increased rice yield by increasing soil physical properties, soil organic carbon, nutrient uptake and maintaining soil temperature. the present study revealed that, biochar increased grain yield by increasing the number of effective tillers and filled grain. application of 2, 4 and 6 t ha−1 of biochar enhanced grain yield of rice by 15, 18 and 10%, respectively, compared with control (table 3). this result was in agreement with zhang et al. (2012) who noticed that application of rice biochar at the rate of 10 t ha–1 enhanced rice grain yield by 10%. chen et al. (2021) also stated that biochar application increased grain yield and yield attributes. application of biochar under salt stress conditions increased grain yield of rice. upon exposure to 1600 ppm nacl, grain yield enhancement was 37, 42 and 30% for the application of 2, 4 and 6 t ha−1 of biochar, respectively (table 3). however, in response to 2800 ppm nacl, all rice plants died before harvesting time irrespective of different biochar levels. zhang et al. (2019) revealed that biochar application reduces salt induced damages and increased rice yield under salt stress conditions. table 3. effect of nacl and biochar on yield attributes and yield of rice (brri dhan62) treatments effective tillers hill−1 (no.) filled grains panicle−1 (no.) 1000-grain wt. (g) grain yield pot−1 (g) straw yield pot−1 (g) effect of salt s0 9.099 a 61.07 a 22.90 a 39.21 a 141.46 a s1 7.34 b 51.89 b 22.32 a 28.09 b 116.16 b s2 0 c 0 c 0 b 0 c 0 c lsd(0.05) 0.35 2.41 0.67 1.24 5.13 cv (%) 8.87 8.90 6.21 7.7 8.31 effect of biochar b0 4.93 b 35.58 b 15 20.27 c 82.31 b b1 5.74 a 38.91 a 15.25 23.31 ab 85.99 ab b2 5.94 a 39.22 a 15.04 23.84 a 91.37 a b3 5.3 b 36.91 ab 14.99 22.31 b 83.81 b lsd(0.05) 0.40 2.79 ns 1.43 5.93 cv (%) 8.87 8.90 6.21 7.7 8.31 combined effect of salt and biochar s0b0 9.03 ab 62.65 a 23.250 a 38.66 a 141.24 a s0b1 9.09 ab 62.82 a 22.750 ab 39.58 a 141.99 a s0b2 9.33 a 61.17 ab 22.625 ab 40.19 a 145.74 a s0b3 8.95 ab 57.67 bc 22.975 ab 38.39 a 136.87 a s1b0 5.75 e 44.08 d 21.750 b 22.13 d 105.70 d s1b1 8.12 c 53.92 c 23.000 ab 30.35 bc 116.00 c response of biochar on growth and yield of aman rice 111 s1b2 8.5 bc 56.50 bc 22.500 ab 31.34 b 128.37 b s1b3 7 d 53.07 c 22.020 ab 28.54 c 114.56 c s2b0 0 f 0 e 0 c 0 e 0 e s2b1 0 f 0 e 0 c 0 e 0 e s2b2 0 f 0 e 0 c 0 e 0 e s2b3 0 f 0 e 0 c 0 e 0 e lsd(0.05) 0.70 4.83 1.35 2.48 10.27 cv (%) 8.87 8.90 6.21 7.7 8.31 straw yield straw yield of rice decreased upon exposure to different level of salinity (table 3). upon exposure to 1600 and 2800 ppm nacl, straw yield of rice declined by 18 and 100%, respectively, compared with control. salinity drastically reduced the straw yield of rice by decreasing photosynthesis, nutrient uptake (siddique et al., 2015), and tiller number (islam et al., 2022). the present study revealed that application of 2 and 6 t ha−1 of biochar have no impact on straw yield of rice (table 3). however, application 4 t ha−1 of biochar in brri dhan62 uplifted straw yield production by 11%. the combined effect of application of biochar and nacl had significant influence on straw yield of rice. in non-saline conditions, all level of biochar showed similar results whereas in 1600 ppm nacltreated rice plant, application of 2, 4 and 6 t ha−1 of biochar increased straw yield by 9, 21 and 8%, respectively. however, upon exposure to 2800 ppm nacl, all rice plants died before harvesting time irrespective of biochar levels. zhang et al. (2019) revealed that biochar application improved anatomical structure and ultra-structure of root which increased leaf mesophyll cell activity, photosynthetic capacity and dry matter accumulation. conclusion salinity decreased growth and yield of aman rice (brri dhan62). exposure of 1600 and 2800 ppm nacl decreased grain yield of rice by 28 and 100%, respectively, by decreasing the number of effective tillers, filled grain and 1000-grain weight. the magnitude of growth and yield reduction increased with increasing the salinity level. application of 2, 4 and 6 t ha−1 of biochar facilitates to recover the saltinduced damages under 1600 ppm nacl stress and extended life duration of rice upto 80 dat under 2800 ppm nacl stress. among the different rates of biochar, application of 4 t ha−1 of biochar showed better result in ameliorating salt-induced damages and yield loss under 1600 ppm nacl stress in rice. references chaganti, v.n. and d.m. crohn. 2015. evaluating the relative contribution of physiochemical and biological factors in ameliorating a saline-sodic soil amended with composts and biochar and leached with reclaimed water. geoderma, 259–260: 45–55. chen, x., s. yang, j. ding and x. sun. 2021. effects of biochar addition on rice growth and yield under water-saving irrigation. water. 13: 209. doi: 10.3390/w13020209. hasanuzzaman, m., k, nahar and m. fujita. 2013. plant response to salt stress and role of exogenous protectants to mitigate salt-induced damages. in: ahmad, p., m.m. azooz, m.n.v. prasad. (eds) ecophysiology and responses of plants under salt stress. new york: springer. pp.25–87. here, s0= 0 ppm nacl s1= 160 ppm nacl s2= 280 ppm nacl b0= 0 t ha−1 biochar b1=2 t ha−1 biochar b2= 4 t ha−1 biochar b0= 6 t ha−1 biochar ns= non significant 112 khanam et al. haque, m.m., h.r. pramanik and j.k. biswas, k.m. iftekharuddaula and m. hasanuzzaman. 2015. comparative performance of hybrid and elite inbred rice varieties with respect to their source-sink relationship. sci. world j. 326802. doi: 10.1155/2015/326802. hussain, s., z. jun-hua, z. chu, z. lian-feng, c. xiao-chuang, y. sheng-miao, a.b. james, h. ji-jie and j. qian-yu. 2017. effects of salt stress on rice growth, development characteristics, and the regulating ways: a review. j. integr. agric. 16(11): 2357-2374. islam, m.r., m.m. islam, s.c. sarker, m.j. ullah and a. rahman. 2022. performances of boro rice as affected by different concentrations of marine water. vietnam j. agri. sci. 5(1): 1326-1336. liu, y., h. lu, s. yang and y. wang. 2016. impacts of biochar addition on rice yield and soil properties in a cold waterlogged paddy for two crop seasons. field crops res. 191: 161-167. mahajan, s. and n. tuteja. 2005. cold, salinity and drought stresses: an overview. arch. biochem. biophys. 444(2): 139-158. munns, r. and m. tester. 2008. mechanisms of salinity tolerance. annu. rev. plant biol. 59: 651-681. mishra, p., k. bhoomika and r.s. dubey. 2013. differential responses of antioxidative defense system to prolonged salinity stress in salt-tolerant and salt-sensitive indica rice (oryza sativa l.) seedlings. protoplasma. 250: 3–19. nahar, k. and m. hasanuzzaman. 2009. germination, growth, nodulation and yield performance of three mungbean varieties under different levels of salinity stress. green farming. 2: 825-829. rahman, a., m.s. hossain, j.a. mahmud, k. nahar, m. hasanuzzaman and m. fujita. 2016b. manganeseinduced salt stress tolerance in rice seedlings: regulation of ion homeostasis, antioxidant defense and glyoxalase systems. physiol. mol. biol. plants. 22(3): 291-306. rahman, a., j.a. mahmud, k. nahar, m. hasanuzzaman, m.s. hossain and m. fujita. 2017. salt stress tolerance in rice: emerging role of exogenous phytoprotectants. in: li, j. (eds.). advances in international rice research. rijeka, crotia. intech. 140-174. rahman, a., k. nahar, m. hasanuzzaman and m. fujita. 2016a. calcium supplementation improves na+/k+ ratio, antioxidant defense and glyoxalase systems in salt-stressed rice seedlings. front. plant sci. 7: 609. doi: 10.3389/fpls.2016.00609. siddique, a.b., m.a. islam, m.a. hoque, m.m. hasan, m.t. rahman and m.m. uddin. 2015. mitigation of salt stress by foliar application of proline in rice. univers. j. agric. res. 3(3): 81-88. sriphirom, p., a. chidthaisong, k. yagi, s. tripetchkul and s. towprayoon. 2020. evaluation of biochar applications combined with alternate wetting and drying (awd) water management in rice field as a methane mitigation option for farmers’ adoption. soil sci. plant nutr. 66(1): 235-246. yang, z., t. vancov, j. penuelas, j. sardans, a. singla, a.f. alrefaei, x. song, y. fang and w. wang. 2021. optimal biochar application rates for mitigating global warming and increasing rice yield in a subtropical paddy field. exp. agric. 57: 283-299. zeng, l., m.c. shannon and c.m. grieve. 2002. evaluation of salt tolerance in rice genotypes by multiple agronomic parameters. euphytica. 127(2): 235-245. zhang, a., r. bian, g. pan, l. cui, q. hussain, l. li, j. zheng, j. zheng, x. zhang and x. han. 2012. effects of biochar amendment on soil quality, crop yield and greenhouse gas emission in a chinese rice paddy: a field study of 2 consecutive rice growing cycles. field crops res. 127: 153-160. zhang, j., z. bai, j. huang, s. hussain, f. zhao, c. zhu, l. zhu, x. cao and q. jin. 2019. biochar alleviated the salt stress of induced saline paddy soil and improved the biochemical characteristics of rice seedlings differing in salt tolerance. soil tillage res. 195: 104372. doi: 10.1016/j.still.2019.104372. zheng, h., x. wang, l. chen, z. wang, y. xia, y. zhang, h. wang, x. luo, and b. xing. 2018. enhanced growth of halophyte plants in biochar-amended coastal soil: roles of nutrient availability and rhizosphere microbial modulation. plant cell environ. 41: 517–532. response of biochar on growth and yield of aman rice 113 bangladesh agron. j. 2023, 26(1): 48-55 escalation of growth and yield in mungbean by sink manipulation: an approach for minimizing pod picking episode a.h.m.m.r. talukder1*, f. ahmed1, i.m. ahmed1, s.n. mahfuza1, a.f.m.s. ahsan1, n. mokarraoma1, m.k. shahadat2, l. nahar3 1plant physiology division, bangladesh agricultural research institute, gazipur-1701, bangladesh 2on-farm research division, bari, daulatpur, khulna, bangladesh 3department of agricultural botany, sher-e-bangla agricultural university, dhaka, bangladesh *corresponding author, email: motiurbari@yahoo.com (received: 14 july 2023, accepted: 15 september 2023) keywords: mungbean, sink manipulation, pod picking, growth, yield abstract farmers’ frequently experience difficulties with their mungbean (indeterminate type) crops harvests due to continuous picking that prolong the pod-picking episode and cause an economic crisis. to solve these issues, deflowering strategies (sink manipulation) were employed in this study following the randomized complete block design. a series of deflowering strategies were started from 40 days after sowing (das) to 55 das; resulting reduced pod production as well as pod picking episode (3 to 4 times) with 6.8-36.8% seed yield compared to control. the minimum seed yield reduction was 6.8%; deflowering at 55 das; with the maximum gross margin tk.112,800 ha−1. considering relative yield, yield reduction, and gross margin, 50 or 55 days produced flower (which would be matured within 60-65 das) could be considered for obtaining the economic seed yield. introduction growth and production of crops are closely related to the potency of sources and sinks as well as their equilibrium condition (zhang and flottmann, 2018, smith and stitt, 2007). however, to increase mungbean productivity, it is necessary to carefully study how the output is influenced by sink and how this varies during the course of development. the efficiency of individual plant parts, such as the leaves, stems, roots, and flowers, is a measure of how successfully they compete to suck in assimilates for potential growth rate (marcelis, 1996). the amount of minerals, sugar, and amino acids available for the growth of other plant parts decreases as a result of developing blooms acting as strong sinks for these nutrients (mossa et al., 2018). leguminous plants have blooms that are designed to miscarry because reproductive organs compete for nutrients. due to the mungbean's indeterminacy before it reached physiological maturity in the first flash, the second flash from fresh racemes develops from upper branches. the second flash from new racemes emerges from upper branches due to the indeterminacy of mungbean earlier than the physiological maturity of the first flash. naturally, the mungbean crop exhibits low-highhigh and low frequencies in pod formation with the first-second-third and later flash of the flower. it's interesting to note that mungbean crops, which have already completed their juvenile period, start to generate new blooms and pods after receiving new management. hence one common method for limiting the plant's ability to reproduce and produce pod is to sink this opposition by eliminating flower buds (kokubun et al., 2009). the mungbean's consistent blooming and fruiting, which displays a weekly and erratic cycle for pod development, causes problems for farmers. in the current study, bari mung-6, a typical flowering and bearing kind of mungbean variety were selected, causing farmers to deal with the bother of pod selection and incur significant costs. to growth and yield in mungbean by sink manipulation 49 reduce the pod-picking event, an experiment was done in which the flowers buds−1 were removed on separate days following seeding while just keeping the pod. materials and methods an experiment was conducted in the pot-house of the plant physiology division, bari, during consecutive two kharif-i (mid-march to mid-june) seasons, 2021 and 2022, to observe sink manipulation impacts on growth, yield, and the pod-picking episode of mungbean. geographically the study area was located between 23°53' and 24°21' n latitudes and in between 90°09' and 92°39' e longitudes and 25 km north of the capital city of bangladesh. this study was done following the randomized complete block design (rcbd) with 10 replications and each pot represented one replication. mother seeds of trial var. bari mung-6 were collected from pulse research centre of bangladesh agricultural research institute (bari), ishurdi, pabna-6600. five deflowering strategies were employed viz. (i) control (no deflowering) (ndf); (ii) deflowering started at 40 days after sowing (das) (df40); (iii) deflowering started at 45 das (df45); (iv) deflowering started at 50 das (df50), (v) deflowering started at 55 das (df55). a total of 50 plastic pots (26 cm top diameter, 20 cm base diameter, and 25 cm height) were organized in the pot-house of the plant physiology division of bari, with 10 pots placed in each replicate blocks. soil and fully decomposed farmyard manure were appropriately blended in a 4:1 volume ratio and sieved through a 2 mm sieve. the sieved soil samples were weighed and placed in pots, each holding around 12 kg of soil. fertilizers @ 18-18-24-12-2.0-1.2 kg ha−1 of n-p-k-s-zn-b were applied in the form of urea, triple super phosphate, muriate of potash, zypsum, zinc sulfate, and boron respectively (ahmmed et al., 2018). the pots had enough perforation system at the bottom for the drainage of water. seven to ten healthy, bigger, and equal-sized mungbean seeds were chosen and treated with provax 200 ec @ 2.5 g kg−1 seeds and sown on 05 march 2021 and 01 march 2022. finally, following uniform emergence two seedlings in each pot were maintained. for growth data, randomly selected three pots were sampled for dry matter measurement at 35 das (just before treatment application), 55 das, and 70 das (after final harvest). sampled plants were separated into leaves, stems, and roots based on plant growth stages. plants were dried in an oven for 72 hours at 80° c ± 2 and calculated total dry matter weight (g plant−1) from the summation of leaves, stem, and roots weights were taken in an electronic balance. besides these, the relative yield, percent yield reduction; absolute growth rate and relative growth rate were calculated by using the following formula: relative yield = yield of deflowered (treated) plants yield of control (non deflowered)plants × 100 percent yield reduction = yield of control pot − yield of deflowering pot yield of control pot × 100 𝐴bsolute growth rate (agr) = ∆w ∆t = (w2−w1) (t2−t1) (garcía et al., 2006) relative growth rate (rgr) = (ln 𝑊2̅̅ ̅̅ ̅̅ ̅̅ −ln 𝑊1̅̅ ̅̅ ̅̅ ̅̅ ) (t2−t1) (hoffmann and poorter, 2002) where, w and t represent weight (g) and time (day), respectively. ln 𝑊2 ̅̅ ̅̅ ̅̅ ̅ and ln 𝑊1 ̅̅ ̅̅ ̅̅ ̅ are the means of the natural logarithm-transformed dry weights. at harvest, yield and yield components data were collected from three pots and analyzed using anova technique least significant different values were calculated at 0.05 probability level wherever the f-test was significant. data analysis was performed with the software environment r 4.2.3 using ‘agricolae’ package (r core team, 2023). 50 talukder et al. results and discussion in the present study, mungbean crops growth and yield showed variable responses due to deflowering at different dates after sowing. the obtained response due to deflowering response and their relevant discussion has been described in this chapter. total dry matter this study evaluated sink manipulation effect on total dry matter (summation of leaf, stem and root) production of mungbean. dry matter at 3 stages of growth was collected viz. 30 das (before imposing deflowering treatment), 55 das and 70 das (just before harvest). in both 2021 and 2022, there were no significant differences in total dry matter production among the treatments at 35 das (figure 1). fig. 1. effect of deflowering treatments viz. no deflowering (ndf), deflowering at 40 days after sowing (df40), deflowering at 45 days after sowing (df45), deflowering at 50 days after sowing (df50) and deflowering at 55 days after sowing (df55) on total dry weight in mungbean during kharif 2021 and 2022. data were collected at 35 days after sowing (das), 55 das and 70 das in 2021. treatments with same letter did not vary significantly. at 35 das, the ranges of total dry matter were 5.19 to 5.39 g plant−1 and 6.70 to 6.92 g plant−1 in 2021 and 2022, respectively. in 2021, at 55 das, total dry matter was recorded highest from df40 (9.42 g plant−1), whereas the lowest but statistically identical total dry weight was found from ndf (7.55 g plant−1) and df55 (7.58 g plant−1). at 70 das, dry matter production in df40 (13.03 g plant−1) was, which was statistically identical with df45 (12.80 g plant−1) and df55 (12.80 g plant−1). similarly in 2022, at 55 das, maximum total dry weight was recorded from df40 (11.41 g plant-1). however, at 70 das, df45 produced maximum dry weight plant−1 (22.07 g plant−1), which was again statistically identical to df50 (21.80 g plant−1) and df55 (21.60 g plant−1) (figure 1). over the growing seasons, total dry weight (g plant−1) was much greater in 2022 than 2021 due to sufficient rainfall during the growth period; however, treatment effects showed almost similar pattern of response (figure 1). in the both 2021 and 2022, there was no discernible difference in total dry weight among treatments when samples were taken at 35 days following sowing. deflowering effects on total dry weight were noticeable when sampling was 55 das and 70 das. overall, it appeared that deflowering at later stage increased total dry weight in all deflowering treatments in both the years and followed increasing pattern as 35 das< 55 das< 70 das. deflowered sunflower plants had a larger stem and leaf dry weight, according to previous research of ho and below (1989). in accordance with their growth and yield in mungbean by sink manipulation 51 findings, deflowering effect in the present study showed increased total dry weight in comparison to control (ndf) (figure 1). on an average, plant dry weight (summation of leaf, stem and root) was increased by 21.1 and 31.0%, 9.85 and 35.2%, 7.75 and 32.6%, and 2.79 and 34.6% at 55 das and 70 das sampling, respectively over the control. this could mainly be attributed to the production of new leaves and absence of potential sink in deflowered treatments. previous study conducted by mitra and ghildhyal (1988) found that deflowered mungbean plants significantly increased in dry weight of leaf, stem, roots and nodules. absolute growth rate and relative growth rate the figure 2 showed the variation in absolute and relative growth rate at 35 das, 55 das and 70 das in different deflowering treatments. in 2021, agr decreased from 35 das to 55 das in all treatments except df40. those treatments showed rapid rise in agr after 55 das up to 70 das. df40, however, demonstrated a continuous increase in agr from 35 to 70 das. in case of rgr, all treatments dropped in rgr from 35 das to 55 das. however, rgr increased in df45, df50 and df55 from 55 das to 70 das. rgr, however, did not rise any further in ndf, and df40 continued to decline. during 2022, all treatments except df40 showed slightly downward trend for rgr from 35 das to 55 das, however, all treatments showed sharp increase up to 70 das. where, rgr were higher in df45 and df55. fig. 2. absolute growth rate and relative growth rate of mungbean as influenced by deflowering treatments during 2021 and 2022. 0 0.01 0.02 0.03 0.04 0.05 0.06 35 das 55 das 70 das r el at iv e g ro w th r at e 2021 ndf df40 df45 df50 df55 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 35 das 55 das 70 das a b so lu te g ro w th r at e 2021 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 35 das 55 das 70 das a b so lu te g ro w th r at e 2022 0 0.02 0.04 0.06 0.08 0.1 35 das 55 das 70 das r el at iv e g ro w th r at e 2022 52 talukder et al. effect of deflowering on plant height deflowering treatments showed variable response in plant height in both years. however, overall plant height was found taller in 2022 than 2021 (figure 3). in 2021, the range of plant height was between 20.4 ± 0.83 in ndf to 22.9 ± 0.58 in df40, which was statistically identical to df45 (22.6 ± 0.37). in 2022, the highest plant height was recorded from df40 (33.0 ± 0.87 cm) and df45 (33.0 ± 1.15 cm). whereas, ndf produced lowest plant height 26.2 ± 0.58 cm. fig. 3. deflowering treatments effect on plant height (cm), number of pods plant−1, pod length (cm), number of seeds pod−1, 100-seeds weight (g) and yield plant−1 (g) in mungbean during kharif 2021 and 2022. effect of deflowering on yield components and seed yield over the growing seasons, the deflowering strategies effects were noticeable in the production of the number of pod plant−1 which was gradually increased with the prolongation of the deflowering period, and control (ndf) treatment produced significantly maximum number of pods plant−1 (23.0 ± 1.15 and 24.0 ± 1.15 in 2021 and 2022, respectively). number of pods growth and yield in mungbean by sink manipulation 53 plant−1 increased gradually when deflowering was delayed i.e., df40<df45<df50<df55 (figure 3). pod length did not differ significantly among the different deflowering strategies in 2022. however, in 2021 there was no significant difference among the deflowering treatments except control (ndf). numerically the highest pod length was found at df40 in both the seasons (figure 3). the number of seeds pod-1 obtained from different deflowering strategies over control had a significant effect. on an average over two growing seasons, the number of seeds pod−1 ranged from 8 to 10 (figure 3). the highest number seeds pod−1 were recorded from df40 in both the seasons (10.2 ± 0.40 and 8.90 ± 0.17, respectively). however, delay in deflowering reduced the number of seeds pod-1 (figure 3). deflowering strategies did not influence on 100-seed weight in 2021. however, in 2022, 100 -seed weight was maximum at df40 (4.64 ± 0.12 g), which was statistically similar to df45 (4.55 ± 0.26 g). there were no significant differences between control (ndf) and df55 (figure 3). the seed yield of mungbean was significantly influenced by different deflowering strategies. among the deflowering treatments, yield (g plant−1) was increased with prolongations of deflowering but decreased compared to the control. the maximum (12.8 g plant−1) and minimum yield (7.43 g plant−1) were found in control (ndf) and df40, respectively in 2021. in a similar fashion, highest seed yield (12.63 g plant−1) was recorded from control (ndf) and lowest yield (8.65 g plant−1) from df40 in 2022 (figure 3). naturally, flower blooming in mungbean crops starts at the base of the inflorescence and continues up to the top, known as the "first flush," and after the first flash pod reaches physiological maturity, flower blooming begins again at the trailing edge of the same inflorescence, known as the "second flash"(mondal et al., 2011). however, in our current study, the results of deflowering found a significant effect on yield-contributing traits and seed yield of mungbean crops. over the growing seasons, the deflowering strategies effects were noticeable in the production of the number of pod plant-1 and were gradually increased with the prolongation of the deflowering period, and control (no deflowering) treatment produced the significant maximum number of pods plant-1. the number of pods plant−1 was increased chronologically retaining the onset flower 40<45<50<55 days over control (figure 2). pod set percentage was decreased by 40.4%, 29.80%, 17.0%, and 10.6% in response to deflowering at 40, 45, 50, and 55 das, respectively than control. results suggested that earlier deflowering treated plants retained fewer flowers than the later deflowering and consequently decreased the number of pods plant−1. pod length (size) was less responsive due to deflowering. though number of pods plant-1 was higher in ndf, however number of seeds pod−1 was lower in ndf along with df50. on the average growing seasons, the number of seeds pod1 ranged from 8 to 10. the percentage of seed set pod−1 was increased by 25.0% and 12.5% at earlier deflowering strategies viz. 40 and 45 das over control, but at later deflowering strategies was almost similar to control. as a result, 100-seeds weight was highest in df40 and df50 only in 2022. the seed yield of mungbean was significantly influenced by different deflowering strategies. among the deflowering treatments, yield (g plant−1) was increased with delay in deflowering, however deflowering did not significantly increase yield compared to the control (ndf). the maximum (12.8 g plant−1) and minimum yield (7.43 g plant−1) were found in control (ndf) and df40. so, it appeared that flower retention at earlier stage increased total number of pods plant−1 and thereby increased yield. seed yield decreased by 41.9%, 41.1%, 25.0%, and 10.0%, from deflowering at 40, 45, 50, and 55 das, respectively. in accordance with the previous study of ojehomon (1970) on cowpea, deflowering on mungbean at early stage of the reproductive cycle decreased grain yield and later deflowering, increased grain yield. 54 talukder et al. relative yield and percent yield reduction over control deflowering at 40, 45, 50, and 55 das, produced 58%, 59%, 75% and 90% relative yield plant-1 over control in 2021, respectively. the similar trend was observed in 2022. here deflowering treatments produced considerably higher relative yield than 2021. delay in deflowering time steadily boosted relative yield. the minimum relative yield of 58% and 68% in 2021 and 2022, respectively were found when all bloomed flowers were removed at 40 das but the maximum relative yield (90% and 97% in 2021 and 2022, respectively) were found when all bloomed flowers were removed at 55 das (figure 4). deflowering at 40, 45, 50, and 55 das reduced the grain yield of mungbean by 42%, 41%, 25%, and 10%, respectively in 2021 in comparison to the control, whereas in 2022 yield reduction from deflowering at 40, 45, 50, and 55 das were 32%, 22%, 14% and 3%, respectively (figure 4). fig. 4. relative yield (%) and % yield reduction over control (no deflowering) at different deflowering treatments in mungbean during kharif 2021 and 2022. cost-benefit analysis from control (ndf) pots, pods were picked maximum of five times, which produced highest seed yield (1.91 t ha−1), and at the same time incurred highest pod picking cost hectare (tk. 52,500 ha−1). (table 1). minimum one-time pod picking was done from deflowering at 40 and 45 das treated plants where marginal benefit cost ratio (mbcr) was 1.50 and 1.12, respectively. the maximum gross margin of tk. 1, 12,800 ha−1 was obtained from deflowering at 55 das treated plants but gave lowest mbcr (0.43). deflowering at 50 das gave gross return of tk. 116,400 and gave highest mbcr (1.60) (table 1). table 1. economic performances under different deflowering strategies treatments economic analysis grain yield (g plant−1) (average of two growing season) grain yield (t ha−1) pod picking episode average pod picking cost of two season (tk ha−1) gross return (tk. ha−1) gross margin (tk. ha−1) mbcr ndf 12.7 1.91 05 times 52,500 1,52,400 99,900 1.00 df40 8.0 1.20 01 times 15,000 96,000 81,000 1.50 df45 9.2 1.38 01 times 15,000 1,10,400 95,400 1.12 df50 9.7 1.46 02 times 30,000 1,16,400 86,400 1.60 df55 11.9 1.79 02 times 30,000 1,42,800 1,12800 0.43 one hectare areas pod picking need 30 labors and per labor cost is tk. 500 day-1. where, ndfno deflowering (control), df40deflowering at 40 days after sowing (das), df45deflowering at 40 das, df50deflowering at 50 das and df55deflowering at 55 das. mbcr=marginal benefit cost ratio 58% 59% 75% 90% -42% -41% -25% -10% 68% 78% 86% 97% -32% -22% -14% -3% -60% -40% -20% 0% 20% 40% 60% 80% 100% 120% df40 df45 df50 df55 r e la ti v e y ie ld ( % ) a n d % y ie ld re d u c ti o n 2021 2022 growth and yield in mungbean by sink manipulation 55 in terms of economic analysis, df40 and df45 facilitate only a single pod picking episode. however, based on the overall cost benefit analysis, df50 and df55 required a couple times of pod picking, where df50 gave higher mbcr (1.60) than any other treatments. conclusion the study showed that mungbean yield varied depending on the sink size (deflowering) at various periods of the reproductive phase. so, it is important to consider potential sink sizes throughout the reproductive phase in order to obtain economic yield. 50 or 55 days produced flower (which would be matured within 60-65 das) could be considered for obtaining the economic seed yield by sacrificing minimum seed yield (6.8%). so, farmers should complete pod picking within 65 das without waiting for the maturity of the remaining pods. acknowledgments this research was funded by climate change project (phase-ii), implemented by kgf, farmgate, dhaka, bangladesh. references ahmmed, s. and m. jahiruddin. 2018. fertilizer recommendation guide-2018. bangladesh agricultural research council (barc), farmgate, dhaka-1215, bangladesh. pp. 223. garcía, a.l., j.a. franco, n. nicolás and r.m. vicente. 2006. influence of amino acids in the hydrophonic medium on the growth of tomato plants. j. plant nutr. 29: 2093-2104 ho, l. and f.e. below. 1989. whole plant senescence of sunflower following seed head removal. plant physiol. 91: 85-90. hoffmann, w.a. and h. poorter. 2002. avoiding bias in calculations of relative growth rate. ann. bot. 80: 37-42. kokubun, m., k. nonokawa, a. kaihattttsu and y. yashima. 2009. mechanisms controlling flower abortion in soybean. tohoku j. agric. res. 60: 23-26. marcelis, l.f. 1996. sink strength as a determinant of dry matte partitioning in the whole plant. j. exp. bot. 47: 1281-1291. mitra, s., and m.c. ghildhyal. 1988. photosynthesis and assimilate partitioning in mungbean in response to source-sink alteration. j. agron. crop sci. 160: 303-308. mondal, m.m.a., m.s.a. fakir, a.k.m.a. prodhan, m.r. ismail and m. ashrafuzzaman. 2011. deflowering effect on vasculature and yield attributes in raceme of mungbean (vigna radiata l. wilczek). aust. j. crop sci. 5: 1339-1344. mossa, h.y, a. mohammed and d. fekadu. 2018. effect of flower bud removal on root quality of anchote (coccinia abyssinica l. cogn.) accessions at bishoftu, ethiopia. asian j. plant sci. res. 8(4): 18-23. ojehomon, o.o. 1970. effect of continuous removal of open flowers on the seed yield of two varieties of cowpea (vigna unguiculata l. walp). j. agric. sci.74: 375-381. r core team 2023. r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. smith, a.m. and m. stitt. 2007. coordination of carbon supply and plant growth. plant cell environ. 30: 1126-1149. zhang, h and s. flottmann. 2018. source-sink manipulations indicate seed yield in canola is limited by source availability. eur. j. agron. 96: 70-76. microsoft word baj 358c__press bangladesh agron. j. 2020, 23(1): 75-81 intercropping garlic (allium sativum) with chilli (capsicum annuum l.) in the haor area of kishoreganj m.f. khatun1, m.s. islam2, m.a. ali 3, m.o. ali4 and q.m. ahmed1 1so, pgrc, bangladesh agricultural research institute, gazipur; 2sso, ofrd, bangladesh agricultural research institute, kishoreganj-2300; 3cso, ofrd, bangladesh agricultural research institute, gazipur; 4cso, prss, bangladesh agricultural research institute, gazipur *corresponding e-mail: mfkhatun79@gmail.com received: 27 july 2020, accepted: 09 august, 2020) keywords: intercropping, haor, chilli, garlic, equivalent yield, economic return abstract haor is one of the uncertain areas for crop production and productivity in bangladesh. traditionally, single cropping practice in a short cropping season is the key obstacle to increase crop productivity. a study was carried out at multi location testing site (mlt), nikly under the on-farm research division (ofrd), bangladesh agricultural research institute (bari), kishoreganj at haor area during the two consecutive rabi seasons of 2015-16 and 2016-17 to evaluate the performance of garlic with chilli intercropping system, its productivity and economic viability. four treatments were consisted viz., sole chilli, one row garlic in between chilli rows, double rows garlic in between chilli rows and garlic with broadcasting chilli. the highest chilli equivalent yield (28 t ha-1) was obtained from one row garlic in between chilli rows and the minimum chilli equivalent yield was (15 t ha-1) obtained in sole chilli. these intercropping practices yield increased 25-89% over the sole chilli. the highest gross return (tk.559400 ha-1), gross margin (tk. 428240 ha-1) and bcr (4.26) were found in one row garlic in between chilli rows and the lowest gross return (tk. 297800 ha-1) and gross margin (tk.188080 ha-1) were obtained from sole chilli but the lowest bcr (1.74) in double rows garlic in between chilli rows. considering the experimental findings of two years, one row garlic in between chilli rows would be a suitable intercropping system for higher productivity and economic return. introduction intercropping is the most common practice which has an important role in increasing productivity and stability of yield. intercropping is a management practice where two or more crops grow simultaneously in the same land area, particularly in the tropics (andrews and kassam, 1976). though, it is a traditional method of crop production but it has not been widely practice by the farmers of haor areas. mainly, intercropping involves crop intensification with respect to both time and space dimensions (ahlawat and sharma, 2002) showing several advantages over the sole cropping, such as enhancement of efficient use of environmental factors (e.g., light, nutrient and soil moisture) and labors, reduces the adverse effect of various biotic and abiotic stress, provides the diversity of food, generates more income, offers insurance against crop failure, higher return and total productivity per unit area (farhad et al., 2014). haor is a wetland in the north-eastern part of bangladesh which physically is a bowl-shaped shallow depression and also seasonally flooded the hundreds of haors and beels with crops (hussain and salam, 2007). the total area of haor type wetland ecosystem in bangladesh is 8 76 khatun et al. million hectares. it includes about 47 major haors and 6300 beels of varying size of which about 3500 are permanent and 2800 are seasonal. (hussain and salam, 2007). in kishoreganj district, mithamain, karimganj, austagram, itna, nikli, bajitpur, kuliarchar, tarail, bhairab, katiadi upazilla are the fully and partially haor area covering 20.6 hectare of land. however, day-by-day the net cultivable land for agriculture is increasing due to siltation through flooding. agriculture is the main profession of the haor people. chilli is one of the major spice and an important cash crop in bangladesh. people prefer and consume it (both dried and green) for its color, pungency and spicy taste (mathukrishnan et al., 1993). about 103381.49 ha of land of bangladesh is under chilli cultivation both rabi (winter) and kharif (summer) seasons. the production is about 136,872 metric tons (bbs, 2017). the review of research work done so far indicated that growth of chilli as intercrops is more beneficial than growing chilli in many situations (aravazhi et al., 1997; natarajan, 1992; sadashiv, 2004). chilli is the major rabi crop at noakhali, bogra. likewise, the farmers of kishoreganj haor areas are cultivating chilli vastly. nevertheless, the spices crop like onion, garlic production is very less in these areas. the framers cultivate onion and garlic as a sole crop and sometimes as a mixed crop in the chilli field. they do not maintain the proper spacing, planting time and management. they also do not analyze the cost and return of these spice crops. if intercropping done properly then, the farmer will get some spices at a time which will be meet up their family requirement. for this reason, the present study was undertaken to evaluate the performance of the intercropping system and to find out a suitable combination of garlic with chilli as well as to enhance productivity and economic return. material and methods the study was conducted at mlt site, nikli under the ofrd, bari, kishoreganj during two consecutive years of 2015-16 and 2016-17. the experimental field was situated on latitude 24º 21ʹ n and 90º 58ʹ e longitude. the experiment was laid out in a randomized complete block design with four dispersed replications. there were four treatments like, sole chilli (t1), one row garlic in between chilli rows (t2), double rows garlic in between chilli rows (t3) and garlic with broadcast chilli (t4). the garlic variety was bari roshun-3 and the chilli variety was balujhuri as local popular variety in the haor area of nikli. among the four treatments garlic with broadcasting chilli was sown followed by the broadcasting system and other treatments were planted in line. the unit plot size was 6 m. x 3 m. the chilli seedlings were transplanted with 30 cm x 25 cm spacing and garlic cloves dibbling were done 10 cm x 10 cm on 24 october 2015 and on 05 november 2016, respectively. fertilizer was applied the rate of n98 p66 k100 s20 b1 kg ha -1 and decomposed cowdung @ 5t ha-1 (frg, 2012). the whole amounts of cowdung, p, s, b and 1/4th of k were applied at the time of final land preparation. remaining k and whole amounts of n were applied in three equal installments at 25, 50 and 75 days after transplantation. irrigation was done as per water requirement. at the seedling stage dithane m 45 @ 2 g l-1 were sprayed in two times to control root rot disease of chilli and tilth @1.5g l-1 were applied for anthracnose disease. weeding and earthing up were done as and when required. in the first year chilli was harvested on 5 january to 12 march 2016 and garlic was harvested on 20 march 2016. the next year, chilli was harvested on 15 january to 20 march 2017 and garlic on 23 march 2017. soil related information of the experimental field the soil type of haor was silty loam. the upper 5 cm was silt and till to 20 cm below 5 cm was loamy but below 1 m from the surface was pit soil. initial soil characteristics of the experimental intercropping garlic (allium sativum) with chilli (capsicum annuum l.) 77 field were determined followed by standard methods of analysis (table-1). the soil was moderately acidic in nature. most of the essential plant nutrients were above the critical limit except phosphorus. table 1. chemical properties of initial soil (0-15 cm depth) of the experimental field soil depth (cm) ph total n (%) ca mg k p s zn meq 100 g-1 µg/g 0-15 5.3 0.10 2.5 1.2 0.34 5 17 1.15 critical limit 0.12 2 0.5 0. 12 10 10 2 weather information of the growing season the weather data has been taken in the growing season carefully (table 2). the highest rainfall 144 mm was occurred at the month of march and the lowest rainfall 8 mm was recorded in the month of january. there was no rainfall occurred on november and december. the maximum temperature was 31.97 0c in october and minimum was 12.93 0c in january. table 2. the average rainfall and temperature distribution during the growing season of 201516 and 2016-17 months monthly average rainfall (mm) monthly average temperature (0c) max. min. october 25.5 31.97 24.27 november 0 27.31 21.5 december 0 20.06 16.54 january 8 17.7 12.93 february 45 23.08 17.48 march 144 27.67 20.05 data collection and statistical analysis each m2 of land in five random places per plot were selected for data collection. data on yield and yield contributing characters were recorded and analyzed statistically with the help of the mstatc program (gomez and gomez, 1984) and mean separation was done as per least significant difference (lsd) test at 5% level of significance. the yield of garlic was converted to the equivalent yield of chilli. chilli equivalent yield (cey) was calculated by the following formula of prasad and srivastava (1991). the economic analysis was calculated based on the existing market price at the harvesting period in the local market of garlic and chilli. all production costs were calculated to find out the economic benefit. yield of intercrop garlic x market price of garlic cey (t/ha) = yield of chilli + market price of chilli results and discussion yield and yield contributing characters of chilli yield and yield contributing characters of chilli were significantly differed except plant population m-2, length of chilli and the individual chilli weight in both the years (table 3). the longest plant 78 khatun et al. height of chilli (89.4 cm and 64.4 cm) was found in t1 (sole chilli) and the shortest plant height (77.3 cm and 56.5 cm) from t4 treatment 2015-16 and 2016-17, respectively. the similar trend was also observed in number of chilli plant-1, and individual weight of chilli. in this study, t1 treatment (sole chili) was planted through row system which ensured optimum population to avoid plant to plant competition that might be influenced the variables like plant height, fruit bearing and chilli length over the treatments in both growing season. the results were agreed with quayyum and maniruzzaman (1995) who mentioned that the sole cropping system having less or no sharing of input, sun and air within the plants. in case of chilli yield, the highest 15.8 and 14 t ha-1 obtained from t1 and lowest 13.8 and 11.6 t ha -1 in t4 treatment both the growing season respectively. islam et al. (2006) and santalla et al. (2001) also reported that crop yield was higher in monoculture as compared to their corresponding intercropped yield. in other sense, the minimum inter-specific competition for space as well as nutrient uptake and water exploitation than t3 and t4 intercropping system, (table 3) might be resulted the highest yield. the results were consistent with the findings by kadalli et al. (1989). in addition, from the two years data, the highest mean yield of chilli (14.9 t ha-1) in t1 treatment which was statistically similar to t2 (14.2 t ha -1) and t3 (13.6 t ha -1) whereas lowest from t4 intercropping system. this might be due to dense population of garlic and chilli in the plots. as such, intercrop reduced yield as compared to monoculture but in most of the intercrops increased the overall profit. similar finding was reported by singh (1985). table 3. yield and yield contributing characters of chilli under the different intercropping system of garlic with chilli during rabi 2015-16 and 2016-17 treatments plant population no. (m2) plant height (cm) no. of chilli plant-1 length of chilli (cm) 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 t1 15 15.0 89.4 64.4 64.0 54.0 5.87 6.83 t2 14 13.4 83.7 63.8 53.7 46.0 5.85 6.29 t3 12 14.7 80.2 59.8 49.0 44.5 5.80 6.16 t4 15 14.8 77.3 56.5 42.4 27.8 5.00 5.57 lsd(0.05%) ns ns 5.11 4.84 8.50 11.4 ns ns cv (%) 1.72 2.41 3.73 3.97 8.15 7.93 1.53 3.08 t1: sole chilli, t2: one row garlic in between chilli rows, t3: double rows garlic in between chilli rows and t4: garlic with broadcasting chilli table 3. cont’d. treatments individual chilli wt. (g) garlic yield (t ha-1) mean yield (t ha-1) chilli yield (t ha-1) mean yield (t ha-1) 2015-16 2016-17 2015-16 2016-17 2015-16 2016-17 t1 2.80 2.76 15.8 14.0 15 t2 2.64 2.55 5.52 5.59 5.56 15.1 13.2 14.2 t3 2.57 2.46 3.60 4.32 3.96 14.3 12.9 13.6 t4 2.43 2.28 1.56 2.97 2.27 13.8 11.6 12.7 lsd (0.05 %) ns ns 4.21 3.24 3.73 2.11 2.56 4.84 cv (%) 1.38 1.57 3.27 2.51 2.89 3.27 4.11 3.69 t1: sole chilli, t2: one row garlic in between chilli rows, t3: double rows garlic in between chilli rows and t4: garlic with broadcasting chilli intercropping garlic (allium sativum) with chilli (capsicum annuum l.) 79 yield of garlic among the three combinations of the intercropping system except sole chilli the highest garlic mean yield (5.56 t ha-1) was found in t2 (one row garlic in between chilli rows) (table 3). it may be the optimum interspace which reduced the competition with nutrients, water, and light as well as minimum pest infestation that helps to produce bigger garlic size. chilli was planted with wider row spacing and the crop has initial slow growth, therefore, it provided excellent opportunities to take up intercrops (duragannavar et al., 2013). according to seran and brintha (2010), intercrops have the potentials to give higher yield than sole crops, greater yield stability and efficient use of nutrients. the lowest garlic mean yield (2.27 t ha-1) was obtained from t4 treatment which was statistically similar to t3 treatment due to effect of closer spacing. chilli equivalent yield the maximum equivalent yield of chilli (28 t ha-1) was found in t2 treatment which was similar to t3 treatment (23.5 t ha -1) due to the higher price of garlic than chilli. the minimum equivalent yield (15 t ha-1) was found in t1 treatment (table 4). the intercropping systems t2, t3 and t4 has been yield increased 89, 60 and 25%, respectively, over the sole chilli (15 t ha-1) (table 4). suresha et al. (2007) reported similar result in different chilli based intercropping systems. saddam (2009) also reported a similar result and they found 1-24% increased ratio compared with the productivity of sole potato and 71-109% compared with the productivity of sole maize. in an intercropping system land equivalent ratio (ler) is higher than any sole crop that means the intercropping competency over the mono-cropping (vandermeer, 1989). jha et al. (2002) and sharma et al. (2000) reported that maximum productivity and more profitability in terms of equivalent yield and monetary return from the intercropping system. economic analysis of different intercropping system of garlic with chili considering the economic analysis, the highest gross return (tk. 559400 ha-1), gross margin (tk. 428240 ha-1) and bcr (4.26) were calculated from t2 (table 4). the lowest gross return (tk. 297800 ha-1), gross margin (tk. 188080 ha-1) were recorded from t1 treatment (sole chili). but the lowest bcr (1.74) was found in t4 treatment due to the total variable cost was higher than the other treatments. islam (2007) indicated that gross margin and benefit-cost ratio (bcr) was higher in intercropping conditions than sole cropping. to increase the profitability additional yield of companion crop has contributed over sole chilli. ijoyah and dzer (2012) reported that greater combined yields and more economic return of intercropping compared to sole cropping. besides, many researchers indicated the intercropping system get a higher gross margin than sole crop (razzaque et al., 2007; alom et al., 2008; bhuiyan et al., 2013; farhad et al., 2014). table 4. equivalent yield and economic performance of different intercropping system of garlic with chilli in the haor area of kishoreganj treatments chilli yield (t ha-1) garlic yield (t ha-1) cey (t ha-1) % yield increased over sole chilli gross return (tk. ha-1) tvc (tk.ha-1) gross margin (tk.ha-1) bcr t1 15 15 297800 109720 188080 2.71 t2 14.2 5.56 28.0 89 559400 131160 428240 4.26 t3 13.6 3.96 23.5 60 470000 270080 199920 1.74 t4 12.7 2.27 18.4 25 366400 115220 246180 3.18 t1: sole chilli, t2: one row garlic in between chilli rows, t3: double rows garlic in between chilli rows t4: garlic with broadcasting chilli ; price: chillitk.20/kg, garlictk.50/kg, cey: crop equivalent yield, tvc: total variable cost, bcr: benefit cost ratio 80 khatun et al. conclusion from the two years study, it is concluded that intercropping garlic with chilli showed more potential than the sole cropping to enhance productivity without hampering the yield of main crop of chilli. among the intercropping systems, one row garlic in between chilli rows was more suitable and productive both agronomic and economic point of view in the haor areas. it is suggested to be effective to increase garlic yield in the haor and beel areas of bangladesh. references andrews, d.j. and a.h. kassam. 1976. the importance of multiple cropping in increasing world food supplies. in: multiple cropping. american society of agronomy, special publication no. 27: 1-10. ahlawat, i.p.s. and r.p. sharma. 2002. agronomic terminology. indian society of agronomy, division of agronomy, indian agricultural research institute, new delhi, india. alom, m.s., n.k. paul and m.a. quayyum. 2008. performance of hybrid maize (zea mays l.) under intercropping systems with mungbean in different planting methods. saarc j. agric. 6: 7382. aravazhi, e., s. natarajan and s. thambaraj. 1997. economics of intercropping in chilli. south indian hort. 45: 139-194. bbs (bangladesh bureau of statistics). 2017. agricultural statistical yearbook of bangladesh. statistics division, bangladesh bureau of statistics. ministry of planning, government of the people’s republic of bangladesh, dhaka. bhuiyan, m.s., s.k. bhowal, i.s. farhad, m.m.u. chowdhury and m. amin. 2013. intercropping soybean with kaon in varying plant population in the coastal area of noakhali region. bangladesh agron. j. 16(1): 81-86. duragannavar, f.m., b.n. patil, s.i. halikatti, y.b. palled, p.l. patil and h.d. mohankumar. 2013. yield, nutrient uptake and economics as influenced by chilli + cotton intercropping system. karnataka j. agric. sci. 26(1): 20-25. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council (barc), farmgate, dhaka. pp.1-274. farhad, i.s.m., m.m.u. chowdhury, s.k. bhowal, a.k. choudhury and a.s.m.m.r. khan. 2014. chilli – garlic intercropping system in coastal saline area. appl. sci. rept. 6(2): 47-50. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research (2nd ed.). newyork: wiley, pp.188–206. hussain, m.m. and m.a. salam. 2007. basic service delivery advocacy: review report. development wheel (dew), dhaka. islam, m.z. 2007. production potential of maize oriented intercropping as influenced by npk level and row arrangement, phd. thesis, dept. agron., bangladesh agril. univ., mymensingh, bangladesh. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effects on the physiological attributes and productivity of maizebush bean intercropping system. bangladesh j. agril. res. 31(3): 353-364. ijoyah, m.o. and d.m. dzer. 2012. yield performance of okra (abelmoschus esculentus l. moench) and maize (zea mays l.) as affected by time of planting maize in makurdi, nigeria. isrn agron. 2012: 7 pages, doi: 10.5402/2012/485810. intercropping garlic (allium sativum) with chilli (capsicum annuum l.) 81 jha, g., d.p. singh, s.k. varshney, s. jumar, s.m.p. khurana, g.s. shekhawat, s.k. pandey and b.p. singh (eds.). 2002. fertilizer requirement of winter maize + potato intercropping system. in: proc. of the global conf. potato, new delhi, india, 6-11 december 1999. 2: 974-977. kadalli, v.g., v.m. bankapur and a.a. patil. 1989. studies on companion cropping of onion with chilli and french bean. j. maharashtra agric. univ. 14(3): 378-379. mathukrishnan, c., t. thangaraj and t. chatterjee. 1993. chilli and capsicum vegetable crops. calcutta: naya prakash. https://doi.org/10.3329/pa.v19i2.16965. natarajan, s. 1992. effect of intercrops on chilli (capsicum annum l.) under semi dry conditions. south indian hort. 40: 273-276. prasad, k. and v.c. srivastava. 1991. pigeonpea (cajanus cajan) and soybean (glycine max) intercropping system under rainfed situation. indian j. agric. sci. 61(4): 243-246. quayyum, m.a. and a.f.m. maniruzzaman. 1995. effect of maize (zea mays l.) and rice (oryza sativa) with black gram (phaseolus mungo). indian j. agron. 40(1): 20-25. razzaque, m.a., s. rafiguzzaman, m.m.m. bazzaz, a. all and m.m.r. talukdar. 2007. study on the intercropping groundnut with chilli at different plant populations. bangladesh j. agric. res. 32(1): 37-43. santalla, m., a.p. rodino, p.a. casquero and a.m. de ron. 2001. interactions of bush bean intercropping with field and sweet maize. european j. agron. 15: 185-196. saddam, a.a. 2009. effect of intercropping of maize with potato on potato growth and on the productivity and land equivalent ratio of potato and maize. j. agric. 4: 164-170. suresha, b.a., t.b. allolli, m.g. patil, b.k. desai and s.a. hussain. 2007. yield and economics of chilli based intercropping system. karnataka j. agric. sci. 20(4): 807-809. sadashiv, b. 2004. production potential of hybrid cotton (gossypium hirsutum) based vegetable intercropping systems under irrigation. m.sc. (agril.) thesis, university of agricultural sciences, dharwad, india. sharma, s.k., r.c. thakur and r.s. rana. 2000. production potential of maize based cropping system under rainfed conditions. agril. sci. digest 20(3): 187-188. singh, h. 1985. studies in relay intercropping of rapeseed in haryana. m.sc. (horticulture). haryana agricultural university, hisar. seran, t.h. and i. brintha. 2010. review on maize based intercropping. j. agron. 9(3): 135-145. vandermeer, j. 1989. the ecology of intercropping. cambridge university press, cambridge, uk. p.237. bangladesh agron. j. 2020, 23(1): 37-46 on-farm evaluation and system productivity of garden pea-boro-t. aman rice cropping pattern in mymensingh m.a.h. khan1, n. sultana1, n. akter2, s. akhter2 and m.r. ali3 1sso, 2so, on-farm research division, mymensingh, bari, bangladesh, and 3pso, rars, jamalpur, bangladesh. corresponding author: helim1367@gmail.com (received: 30 april, 2020, accepted: 17 august, 2020) keywords: garden pea, management, cropping intensity, profitability, production efficiency abstract the experiment was conducted at multi location testing site under on-farm research division, bangladesh agricultural research institute, mymensingh 201617 and 2017-18 to evaluate the agro-economic performance of improved cropping pattern for increasing cropping intensity, system productivity and profitability as compared to farmers’ existing cropping pattern. the experiment was laid out randomized complete block design with six dispersed replications. two cropping pattern viz., improved cropping pattern garden pea (var. bari motorshuti-3) boro (var. brri dhan28) t. aman rice (var. brri dhan32) and farmers’ existing pattern fallow boro (brri dhan28) t. aman rice (var. brri dhan32) as control were tested. improved cropping pattern produced higher mean rice equivalent yield (30.26 t ha-1 yr.-1), production efficiency (74 kg ha-1 day-1 ), land utilization index (72 %) and labour employment (382 man-days ha-1 yr.-1) than farmers’ pattern which were 200, 37, 35 and 55% higher over existing pattern. average gross return (tk.486430 ha-1), gross margin (tk. 284787 ha-1) and marginal benefit cost ratio (4.60) of improved pattern indicate it’s superiority over farmers’ pattern. the fertility status of soil i.e. ph, organic matter, total n, available p, s, zn and b content in soil were increased over the initial soil due to addition of garden pea biomass. thus, inclusion of garden pea in the existing pattern would improve soil health and system productivity as a whole. experimental findings revealed that there is potential for greater adoption of intensified cropping systems with increased productivity and profitability as compared to rice–rice systems in mymensingh region. introduction increased population, food scarcity, poverty, starvation and environmental degradation are the primary challenges of the 21st century (neamatollahi et al., 2017). in the world about 1 billion people keep on hungry every day due to the inadequate food supply and this number will rise up to 2 billion by 2050 (faostat, 2014). for the developing countries of asia and africa, this situation insists on the increasing momentum in agricultural production with more than 70 percent increase in the coming decades (neamatollahi et al., 2017). to enhance agriculture productivity improved cropping patterns and better management practices are essential. land and water resources are becoming very limited due to the rapid change in population and urbanization. subsequently, to determine the optimal use of the available resources improved 38 khan et al. cropping pattern has been developed for exploiting the net profit subjected to some limitations (osama et al., 2017). bangladesh covers about 14.84 m ha (million hectares) of total land and among this 3.74 m ha (25% of the total) is not appropriate for cultivation due to deployment for urban areas, commercial buildings, countryside homesteads, roads etc. (quasem, 2011). bangladesh also suffers frequently from different normal disasters that may get worse in the long run as a result of climate change (hossain et al., 2016 and rokonuzzaman et al., 2018). as such, there is a scope of increasing cropping intensity from existing level of 195% by improving the existing cropping patterns through including short duration crops viz. mustard, potato, mungbean, garden pea and other vegetables in the rice based cropping systems during whole year by augmenting productivity of each crops (ladha et al., 2016 and datta et al., 2017). the existing major cropping pattern of mymensingh region is fallow-boro-t. aman rice which covers about 66 % of the total cultivated land (dae, 2018). only rice production is not profitable and suitable for the farmers of this area due to it requires huge amount of irrigation water for boro cultivation as well as soil native fertility decline for monoculture of rice (sarker et al., 2020). so an adaptation of alternative cropping patterns to support the most efficient use of the limited natural resources is a prime need for recent days. a huge part of land remains fallow 2 to 3 months after harvest of t. aman rice in this area. garden pea can easily be cultivated in this region after harvest of t. aman rice and can get high economic return within a short time. it is also adds nutrient in soil that improves soil health as it is a leguminous crop. considering the above facts, the present experiment was undertaken for increasing cropping intensity and productivity by incorporating garden pea in rice based cropping system and increasing farmer’s income and creating employment opportunity with improved cropping pattern garden pea boro-t. aman rice. materials and methods the experiment was conducted at multi location testing (mlt) site under on-farm research division, bangladesh agricultural research institute, mymensingh at farmers’ field under irrigated condition to increase cropping intensity and productivity by incorporating garden pea in the existing cropping system (fallow – boro t. aman rice) during 2016-17 and 2017-18. the experimental site belongs to old brahmaputra floodplain agro-ecological zone (aez-9) of mymensingh. the geographical position of the area is between 24o45/ n latitude and 90o24/ e longitude. the land was medium high and the soil of the study area was sandy loam in texture with well drainage system. the meteorological data of the experimental site revealed that the highest temperature prevails in august-september and the lowest in december. in both years, there is no precipitation in december. maximum rainfall was received during the months of may to september. the meteorological data of the experimental site revealed that the highest temperature prevailed (32.5 and 32.8 oc) in august and the lowest (9.0 and 11.20 oc) in december during two consecutive years. the crop received 213.7 mm and 64.7 mm rain showers from october to march in two successive years. the relative humidity was highest (87.1 & 88.0 %) in july and lowest (75.9 and 74.8%) in march during two consecutive years. monthly mean maximum and minimum air temperature (32.5 and 20.5 oc), total rainfall (1973 mm) and relative humidity (82.7 %) were prevailing during the study period. initial soil sample was collected and analyzed (table 1). general soil types predominantly include dark grey floodplain soils. organic matter content was low, top soils were acidic to neutral and sub-soils were neutral in reaction. in general, fertility level including n, k and b was very low. system productivity of garden pea-boro-t. aman rice cropping pattern 39 the experiment was laid out in a randomized complete block design with six dispersed replications. two cropping pattern viz., improved cropping pattern garden pea (var. bari motorshuti-3) boro (var. brri dhan28) t. aman rice (var. brri dhan32)) and farmers’ existing pattern fallow boro (brri dhan28) t. aman rice (var. brri dhan32) were the treatments variables of the experiment. the unit plot size was 600-800 sq.m. all field operations and management practiced both improved and farmers’ patterns are presented in table 4. garden pea was the first crop of the sequence. the seeds were sowing 30 cm × 20 cm a part rows at the rate of 40 kg ha-1 on 12-17 november, 2016 and 14-18 november 2017, in two consecutive years. fertilizer management was done followed by frg (2012) and intercultural operations like weeding, mulching, irrigation and pest management were done to support the normal growth of the crops. the crop was harvested on 10-27 january, 2017 and 17-31 january 2018 in 1st and 2nd year, respectively. after harvest of garden pea pods, the plants were incorporated into soil. boro rice was the second crop of the sequence. boro rice seedlings were grown in adjacent plot and 35-40 days old seedlings were transplanted with a spacing of 20 cm × 15 cm. boro rice seedlings were transplanted on 14-20 february, 2017 and 17-23 february, 2018 and harvested on 18-26 may, 2017 and 21-31 may, 2018 in 1st and 2nd year, respectively. fertilizer management and other intercultural operations like weeding, mulching, irrigation and pest management were done according to brri (2013). rice plant was harvested at 30 cm height from soil surface and remaining parts of the plants were incorporated in soil. t. aman rice was the third crop of the sequence. t. aman rice seedlings were grown in adjacent plot and 25-30 days old seedlings were transplanted with a spacing of 20 cm × 15 cm. on 1520 july, 2017 and 17-24 july, 2018 and harvested on 16 to 23 october, 2017 and 20-31 october 2018 in two successive years. fertilizer management and other intercultural operations were done properly to support the normal growth of the crop according to brri (2013). t. aman rice plants were harvested at 15 cm height from soil surface and remaining parts of the plants were incorporated in soil. in farmers’ pattern, 40-45 days old seedlings of boro rice and 30-35 days old seedlings of t. aman rice were transplanted with a20 cm × 15 cm spacing. boro rice seedlings were transplanted on 08-12 february, 2017 and 05-11 february, 2018 and harvested on 18-22 may, 2017 and 13-19 may, 2018 in 1st and 2nd years, respectively. t. aman rice seedlings were transplanted on 08-14 august, 2017 and 06-13 august 2018, and harvested on 12-18 november, 2017 and 11-18 november, 2018. fertilizer management and other intercultural operations like weeding, mulching, irrigation and pest management were done according to farmers’ own practices. plot-wise yield data were determined on an area basis of each plot. grains and straw were sun dried and weighed adjusting at 12 % moisture content for rice. agronomic performance like field duration, rice equivalent yield (rey), production efficiency and land utilization index were calculated as follows. rice equivalent yield (rey): for comparison between crop sequences, the yield of every crop was converted into rice equivalent on the basis of prevailing market price of individual crop (verma and modgal, 1983). rice equivalent yield (rey) was computed as yield of individual crop multiplied by market price of that crop divided by market price of rice. rice equivalent yield (tha-1yr-1) = riceof pricemarket cropof that pricemarket crop individualof yield × production efficiency: production efficiency value in terms of kgha-1day-1 was calculated by total main product in a cropping pattern divided by total duration of crops in that pattern (tomar and tiwari, 1990). 40 khan et al. production efficiency (kgha-1day-1) = ∑ ∑ id iy where, yi = yield (kg) of i th crop, di= duration (day) of i th crop of the pattern and i = 1, 2, 3, 4 land utilization index (lui): it was worked-out by taking total duration of crops in an individual cropping pattern divided by 365 days (rahman et al., 1989). it was calculated by the following formula: land utilization index (%) = where d1, d2, d3 and d4 the duration of 1 st, 2nd 3rd and 4th crop of the pattern cost and return analysis was done on the basis of prevailing market price of the commodities. the inputs used included seed, fertilizer, labour and insecticides. the mbcr of the farmer’s prevalent pattern and any replacement for it can be computed as the marginal value product ((mvp) over the marginal value cost (mvc). the marginal of prevalent pattern (f) and any potential replacement (e) which was computed as (cimmyt, 1988). marginal benefit cost ratio (mbcr) = mvc mvp (f) tvc (e) tvc (f) returngross (e) returngross = results and discussion soil fertility status: the status of soil ph, organic matter content, total n, available p, k, s, zn and b in initial soil as well as after completion of two cropping cycle of garden pea-boro-t. aman rice cropping pattern is shown in table 1. soil chemical analysis of improved cropping pattern revealed that on an average, ph and organic matter content of the soil increased slightly. initially the ph of the soil was 6.07 but after completion of two cropping cycle the soil ph slightly increased to near 6.09. it was also found that the fertility status of soil i.e. organic matter, total n, available p, s, zn and b contents in soil were increased slightly over the initial soil due to addition of garden pea biomass. however, k in the improve pattern tended to be lower than the farmers one, which indicated to add more k in soil to improve k content. rao and bhardwaj (1980) conclusively proved that pulses receiving optimum fertilizer, especially p, had more pronounced residual effect both in terms of n and p on the succeeding cereals. table 1. effect of garden pea inclusion in fallow – boro t. aman rice cropping pattern on soil fertility status of the farmers’ field in mymensingh during 2016-17 and 2017-18 sample land type rainfed/ irrigated ph om (%) total n (%) k (meq100-1 g) p (bray) s zn b (µg g-1) initial mhl irrigated 6.07 1.37 0.074 (vl) 0.069 (vl) 18.13 (opt.) 22.12 (m) 1.27 (m) 0.09 (vl) post harvest mhl irrigated 6.09 1.39 0.075 (vl) 0.067 (vl) 21.60 (h) 22.54 (opt) 1.29 (m) 0.12 (vl) note: mhl = medium high land, vl = very low and l = low 100 365 d4 d3d2d1 × +++ system productivity of garden pea-boro-t. aman rice cropping pattern 41 organic matter added to soil through incorporation of non-economic plant parts helped to maintain the quality of soil (table 2). these results are supported by mondal et al. (2015) and khan et al. (2018) who found that inclusion of mungbean in the existing farmer’s cropping pattern improve the soil fertility status. table 2. addition of organic matter from crop residues in soil of improved and farmers’ existing cropping pattern at mymensingh during 2016-17 and 2017-18 crops improved pattern added residues (t ha-1) farmers’ pattern added residues (t ha-1) 2016-17 2017-18 mean 2016-17 2017-18 mean garden pea 1.36 1.34 1.35 boro rice (30 cm) 1.35 1.27 1.31 1.25 1.29 1.27 t. aman rice (15 cm) 0.69 0.67 0.68 0.63 0.67 0.65 total 3.40 3.28 3.34 1.88 1.96 1.92 crop management: crop management practices under improved cropping pattern garden peaboro t. aman rice and farmers existing cropping pattern fallow boro t. aman rice are shown in table 3. average field duration of improved cropping pattern took 261 days for completion of one cycle, while existing cropping pattern required 195 days for completion of one cycle. average turnaround time for improved cropping was 104 days whereas it was 171 days to complete one cycle of existing cropping pattern. table 3. crop management practices of improved cropping pattern garden pea – boro t. aman rice (ip) and farmers’ existing cropping pattern fallow – boro t. aman rice (fp) in mymensingh during 2016-17 and 2017-18 parameters years improved cropping pattern (ip) farmers’ existing pattern(fp) crop garden pea boro rice t. aman rice fallow boro rice t.aman rice variety 2016-17 2017-18 bari motorshuti-3 bari motorshuti-3 brri dhan28 brri dhan28 brri dhan32 brri dhan32 brri dhan28 brri dhan28 brri dhan32 brri dhan32 spacing (cm) 2016-17 2017-18 30×20 30×20 20×15 20×15 20×15 20×15 20×15 20×15 20×15 20×15 fertilizer dose (kg npksznb ha-1) 2016-17 2017-18 28-33-60-0501-01 150-20-6518-1.3-0 90-10-3512-1-0 160-2060-20-0-0 100-2024-0-0-0 sowing/ planting time 2016-17 2017-18 12-17 nov. 14-18 nov. 14-20 feb. 17-23 feb. 1520 july 17-24 jul 08-12 feb 05-11 feb 08-14 aug 06-13 aug seedling age (days) 2016-17 2017-18 35-40 35-40 25-30 25-30 40-45 40-45 30-35 30-35 irrigation (no.) 2016-17 2017-18 01 01 15 14 6 5 17 18 7 6 weeding (no.) 2016-17 2017-18 01 01 02 02 01 01 02 02 01 01 harvesting time 2016-17 2017-18 10-27 jan. 17-31 jan 18-26 may 21-31 may 16-23 oct 20-31 oct 18-22 may 13-19 may 12-18 nov. 11-18 nov. field duration (days) 2016-17 2017-18 66 70 95 96 96 99 99 97 97 96 turnaround time (days) 2016-17 2017-18 25 22 28 27 55 51 87 88 82 84 42 khan et al. the newly introduced crop in the farmers existing pattern was garden pea in the rabi season to use fallow period. result indicated that garden pea could be easily fitted in the existing cropping pattern. yield performance: green pods/ grain yield of garden pea, boro and t. aman rice of improved and existing cropping pattern have been present in table 4. pod yields of garden pea were 8.38 and 8.74 t ha-1 and stover yields were 1.36 and 1.34 t ha-1 in two consecutive years, respectively. two years average green pod and stover yields of garden pea were 8.56 and 13.5 t ha-1. grain yields of boro rice were 5.84 and 5.92 t ha-1 and straw yields were 5.94 and 5.98 t ha-1 in 1st and 2nd year, respectively. mean grain and straw yields of boro rice were 5.88 and 5.96 t ha-1, respectively. grain yields of t. aman rice were 4.40 and 4.42 t ha-1 and straw yields were 4.55 and 4.51 t ha-1 in the two successive years. mean grain and straw yields of t. aman rice were 4.41 and 4.53 t ha-1. it was revealed that all the component crops under improved pattern gave higher grain yield as well as by-product yield (table 5). average yield of boro and t. aman rice in improved cropping pattern increased by 2 % over farmers’ practice (fp). the yield of improved pattern was higher presumably due to improved production technologies and use balanced fertilizers for component crops. table 4. yield of different crops under improved cropping pattern garden pea boro t. aman rice (ip) and farmers’ existing cropping pattern (fp) in mymensingh during 2016-17 and 2017-18 parameters years improved cropping pattern (ip) farmers’ cropping pattern (fp) garden pea boro rice t. aman rice fallow boro rice t. aman rice pod/grain yield (t ha-1) 2016-17 2017-18 mean 8.38 8.74 8.56 5.84 5.92 5.88 4.40 4.42 4.41 5.74 5.77 5.76 4.28 4.36 4.32 stover straw yield (t ha-1) 2016-17 2017-18 mean 1.36 1.34 1.35 5.94 5.98 5.96 4.55 4.51 4.53 5.80 5.92 5.86 4.40 4.46 4.43 in farmers’ existing cropping pattern, grain and straw yields of boro and t. aman rice have been present in table 4. in the existing pattern, grain yields of boro rice were 5.74 and 5.77 t ha-1 and straw yields were 5.80 and 5.92 t ha-1 in two successive years, respectively. mean grain and straw yields of boro rice were 5.76 and 5.86 t ha-1, respectively. grain yields of t. aman rice were 4.28 and 4.36 t ha-1 and straw yields were 4.40 and 4.46 t ha-1 in the two consecutive years. mean grain and straw yields of t. aman rice were 4.32 and 4.43 t ha-1. average grain yield of boro rice in fallow – boro t. aman rice cropping pattern was obtained 5.86 t ha-1. the result is in conformity with the findings of sultana et al. (2014) for the variety brri dhan28 in mustard – boro t. aman cropping pattern at mymensingh region. system productivity: total productivity of cropping systems was evaluated in terms of rice equivalent yield (rey) and it was calculated from the yield of component crops. rice equivalent yields (rey) of improved cropping pattern (garden pea – boro t. aman rice) were estimated 29.79 and 30.70 t ha-1 yr-1 which were 197 and 203 % higher over existing cropping pattern in two successive years. the mean rice equivalent yield of improved cropping pattern was 30.26 t ha-1 yr.-1 which was 200% higher against existing cropping pattern (10.08 t ha-1 yr-1) due to introduction of new crop and improved management practices. higher rice equivalent yield indicates higher productivity and efficiency of the improved pattern. (table 5). this findings were supported by nazrul et al. (2017) and khan et al. (2018). system productivity of garden pea-boro-t. aman rice cropping pattern 43 production efficiency: the higher production efficiency in terms of kg ha-1 day-1 was calculated from improved cropping pattern than existing cropping pattern (table 5). mean production efficiency of improved cropping pattern was found 74 kg ha-1day-1 which was 37 % higher over farmers’ existing cropping pattern (54 kg ha-1 day-1). the higher production efficiency of improved cropping pattern might be due to inclusion of high yielding garden pea as well as improved management practices. similar trend of findings were noted by nazrul et al. (2017) and khan et al. (2018) in production efficiency of improved cropping pattern. land utilization index (lui): land utilization index is the effective use of land in a cropping year, which mostly depends on crop duration. mean land utilization index (lui) indicated that improved cropping pattern used the land for 72 % period of the year, whereas farmers’ existing pattern used the land for 54 % period of the year. in improved cropping pattern, land use efficiency was 35 % higher than farmers’ practice. the higher land use efficiency in improved cropping pattern because this pattern occupied the field for longest period (261 days) whereas the farmers’ pattern occupied the field for 195 days of a year (table 5). as a result labour utilization could be more in the improved cropping pattern than existing one. analogous trend of findings were cited by nazrul et al. (2017) and khan et al. (2018) in land utilization index of improved cropping pattern. labour employment generation: human labour was employed for land preparation, sowing, and transplanting, fertilizing, weeding, pesticide application, harvesting, carrying, threshing, cleaning and drying. it was observed that mean total number of human labour used for crops production under improved cropping pattern was 382 man-days ha-1 year-1 which was generated 55% higher labour employment than that of existing cropping pattern (246 man-days ha-1 year-1). improved cropping pattern engaged the field for longest period (261 days) whereas the farmers’ pattern occupied the field for 195 days of a year. as a result labour utilization could be more in the improved cropping pattern than existing one. it was also generated employment of women, children and aged people due to inclusion of garden pea (table 5). table 5. rice equivalent yield, production efficiency, land utilization index and labour employment of improved cropping pattern (ip) and farmers’ existing cropping pattern (fp) in mymensingh during 2016-17 and 2017-18 year cropping pattern rey (tha-1yr-1) pe (kgha-1day-1) lui (%) labour employment (man-days ha-1 yr-1) 2016-17 ip fp 29.79 10.02 146 51 70 54 385 244 2017-18 ip fp 30.70 10.13 76 53 73 53 379 248 mean ip fp 30.26 10.08 74 54 72 54 382 246 % increased/decreased over fp 200 37 35 55 note: rey = rice equivalent yield, pe = production efficiency, lui = land utilization index, ip = improved pattern and fp = farmers’ pattern cost and return analysis: the cost and return analysis are presented in table 6. it indicated that higher return was found in improved cropping pattern (garden pea – boro t. aman rice) than farmers’ existing pattern (fallow – boro t. aman rice). two years average gross return of the improved pattern was tk.486430 ha-1 which was 183 % higher over farmers’ pattern (tk. 171705 ha-1). mean total variable cost of improved cropping pattern was tk. 201643 ha-1 which was 51% higher than farmers’ pattern (tk. 133200 ha-1) which was probably due to 44 khan et al. inclusion of garden pea in the pattern as well as management practices. average gross margin was substantially higher in the improved pattern (tk. 284787 ha-1) than farmers’ pattern (tk. 38506 ha-1). the higher gross margin of the improved pattern was achieved mainly due to higher yield advantages of the component crops. additional gross margin (640%) was achieved by adding 51 % extra cost in the improved pattern. these findings are supported by sarker et al. (2014) who reported that wheat – mungbean t. aman rice produced the higher economic benefit in terms of bcr. mean marginal benefit cost ratio (mbcr) was found 4.60 which further indicated the superiority of the improved pattern over farmers’ one. thus, inclusion of garden pea in the existing pattern might be agronomically viable, economically profitable and environmentally sustainable for the farmers’ in the study site. table 6. gross return, total variable cost, gross margin and marginal benefit cost ratio (mbcr) of garden pea – boro t. aman rice (ip) and fallow – boro t. aman rice (fp) in mymensingh during 2016-17 and 2017-18 year cropping pattern gross return (tk. ha-1) total variable cost (tk. ha-1) gross margin (tk. ha-1) mbcr 2016-17 ip fp 471670 170700 200640 132537 271030 38163 4.42 2017-18 ip fp 501190 172710 202646 133862 298544 38848 4.78 mean ip fp 486430 171705 201643 133200 284787 38506 4.60 % increased/decreased over fp 183 51 640 note: price: green pod = tk. 35.00 kg-1, rice = tk. 15.00 kg-1, rice straw = tk. 2.00 kg-1 and stover = tk. 1.00 kg-1 apparent soil nutrient balance: total n, p, k and s uptake by different crops at the farmer’s field are presented in fig.1. the partial net balance of n was negative in both the patterns and ranged from -91 to -214 kg ha-1. nitrogen replenishment through chemical fertilizer and organic matter addition either singly or in combination was not enough to balance n removal by crops presumably due to substantial loss of the applied n from the soil. -300 -200 -100 0 100 200 300 400 n p k s n p k s n p k s nutrient uptake (kgha1) nutrient added (kgha-1) apparent nutrient balance (kgha-1) fig 1. effect of improved pattern and farmers' pattern on soil nutrient balance in mymensingh improved pattern farmers' pattern system productivity of garden pea-boro-t. aman rice cropping pattern 45 the p balance was favourable as expected due to individual crop basis fertilization. excess amount of p accumulated in the soil and positive effect of p was reflected in the improved pattern. in farmers’ pattern, p balance was also positive. however, the partial net balance of k was negative and ranged from -63 to -92 kg ha-1. this may lead to k depletion in the long run. there was a positive balance of s in both the patterns and ranged from 7 to 31 kg ha-1. these results are supported by khan et al. (2018) who reported the similar trend of nutrients in wheat – mungbean t. aman rice cropping pattern. conclusion results of the two years trial clearly indicated that garden pea (var. bari motorshuti-3) boro (var. brri dhan28) t. aman rice (var. brri dhan32) cropping pattern was more productive and profitable than the farmers existing cropping pattern fallow boro (var. brri dhan28) -t. aman rice (var. brri dhan32). thus, garden pea can be successfully accommodated in the existing farmers’ pattern with total crop duration (261 days) in mymensingh region to increase cropping intensity and system productivity with profitability. furthermore, through this cropping pattern the soil health may be improved and the farmers could cultivate year round crop successfully and creates employment opportunity of labour forces. references brri (bangladesh rice research institute). 2013. modern rice cultivation, 17th edition, bangladesh rice research institute, joydebpur, gazipur-1701. cimmyt (international maize and wheat improvement centre). 1988. agronomic data to farmer recommendation: an economic training manual. international maize and wheat improvement centre, mexico, d. f. 79p. dae (department of agriculture extension). 2018. paper presented in the regional research extension review and program planning workshop at regional agricultural research station, bari, jamalpur. datta, a., h. ullah and z. ferdous. 2017. water management in rice. in: chauhan, b.s., k. jabran, g. mahajan (eds.) rice production worldwide. pp.255–277. https://doi.org/10.1007/9783-319-47516-5_11. faostat (food and agriculture organization corporate statistical database). 2014. fao, rome, italy. frg (fertilizer recommendation guide). 2012. bangladesh agricultural research council (barc), farmgate, new airport road, dhaka-1215. p.274. hossain, m.s., a. hossain, m.a.r. sarkar, m. jahiruddin, j.a. teixeira da silva and h.m. israil. 2016. productivity and soil fertility of the rice-wheat system in the high ganges river floodplain of bangladesh is influenced by the inclusion of legumes and manure. agric. ecos. environ. 218: 40–52. https://doi.org/10.1016/j.agee.2015.11.017. khan, m.a.h., n. sultana, n. akter, m.s. zaman and a.k. choudhury. 2018. increasing cropping intensity and productivity through mungbean inclusion in wheat-fallow-t. aman rice cropping pattern. bangladesh j. agril. res. 43(2): 333-343. ladha, j.k., a.n. rao, a.k. raman, a.t. padre, a. dobermann, m. gathala and s. noor. 2016. agronomic improvements can make future cereal systems in south asia far more productive and result in a lower environmental footprint. global change biol. 22: 1054–1074. ttps://doi.org/10.1111/gcb.13143. 46 khan et al. mondal, r.i., f. begum, a. aziz and s.h. sharif. 2015. crop sequences for increasing cropping intensity and productivity. saarc j. agri. 13(1): 135-147. nazrul, m.i., m.k. hasan and m.r.i. mondal. 2017. production potential and economics of mungbean in rice based cropping pattern in sylhet region under aez 20. bangladesh j. agril. res. 42(3): 413-424. neamatollahi, e., j. vafabakhshi, m.r. jahansuz and f. sharifzadeh. 2017. agricultural optimal cropping pattern determination based on fuzzy system. fuzzy infor. eng. 9: 479–491. https://doi.org/10.1016/j.fiae.2017.12.004. osama, s., m. elkholy and r.m. kansoh. 2017. optimization of the cropping pattern in egypt. alexandria eng. j. 56: 557–566. https://doi.org/10.1016/j.aej.2017.04.015. quasem, m.a. 2011. conversion of agricultural land to non-agricultural uses in bangladesh: extent and determinants. bangladesh dev. studies, 34: 59-85. rahman, m.m., m.h. khan, r.n. mallick and r.e. hudgens. 1989. guidelines for farming systems research methodology. bangladesh agricultural research council, farmgate, dhaka-1215. rao, j.v. and r.b.l. bhardwaj. 1980. influence of residual fertility on green gram in intensive cropping system. indian j. agron. 25: 97-101. rokonuzzaman, m., m.a. rahman, m. yeasmin and m.a. islam. 2018. relationship between precipitation and rice production in rangpur district. prog. agri. 29: 10-21. https://doi.org/10.3329/pa.v29i1.37476. sarker, m.a.z., m.a. alam, a. hossain and m.a. mannaf. 2014. agro-economic performance of crop diversification in rice based cropping systems of northwest bangladesh. agric., forest. fish. 3(4): 264--270. sarker, u.k., s. monira and m.r. uddin. 2020. on-farm evaluation and system productivity of wheat-jutet. aman rice cropping pattern in char area of bangladesh. agril. sci. 2(1): 3946. sultana, s., m.s. zaman, m. yasmin and s. akhter. 2014. development of mustard-boro-t. aman rice cropping pattern against fallow-boro-t. aman rice cropping pattern. bangladesh j. agriculturist. 7(1): 95-99. tomer, s.s. and a.s. tiwari. 1990. production potential and economics of different crop sequences. indian j. agron. 35 (1&2): 30-35. verma, s.p. and s.c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2): 89-92. bangladesh agron. j. 2025, 28(1): 1-7 intercropping onion and garlic with brinjal under different planting system m. z. ali*, a. a. begum, j. a. chowdhury, s. s. kakon and m. a. k. mian agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh *corresponding author, email: zabiedbd71@gmail.com (received: 05 october 2025, accepted: 20 november 2025) keywords: brinjal, brinjal equivalent yield, garlic, intercropping, land equivalent ratio, light interception, onion, yield abstract the experiment was conducted at the agronomy research field of bangladesh agricultural research institute, gazipur during rabi season of 2019-2020 and 2020-21 to find out the suitable crop combination of onion and garlic with brinjal for increasing total productivity, economic return and maximize land utilization through intercropping system. seven treatments viz., t1= brinjal (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal (80 cm × 60 cm) 100%, t6= sole onion (15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100% were used in the study. results showed that light availability on onion and garlic decreased with the increased of shade produced by brinjal canopy over the time up to 95 days after transplanting of onion seedling and planting of garlic cloves. in both the years, throughout the growing period of onion and garlic the maximum light availability was observed in t6 (sole onion) and t7 (sole garlic) treatments followed by t4 treatment (3 row garlic 43% in between two row of brinjal 100%) and t3 treatments (4 row garlic 57% in between two row of brinjal 100%) and the minimum light availability was observed in t1 treatment (4 row onion 57% in between two row of brinjal 100%) followed by t2 treatment (3 row onion 43% in between two row of brinjal 100%). light availability was more in brinjal + garlic intercropping system than brinjal + onion intercropping system throughout the growing period. all the intercropping combinations showed better performance in terms of brinjal equivalent yield, gross return, gross margin and benefit cost ratio (bcr) over sole crops. among the intercropping combination, 4 row garlic (15 cm × 10 cm) 57% in between two row of brinjal (80 cm × 60 cm) 100% was the agronomically most feasible and profitable intercropping system in respect of brinjal equivalent yield (36.42 t ha−1), land equivalent ratio (ler)1.29, gross return (tk.7,28,333 ha−1), gross margin (tk.4,76,596 ha−1) and benefit cost ratio (2.89). introduction bangladesh is a densely populated country. day by day its total cropped area is declining due to urbanization, increase of population and industrialization. as a result, our total food demands are increasing. intercropping is a traditional practice in bangladesh and it increases total productivity per unit area through maximum utilization of land, labour and growth resources (ahmed et al., 2013). by judicious choice of compatible crops and adopting appropriate planting geometry, inter/intra specific competition may be minimized resulting higher total productivity (alom et al., 2013). canopy architecture of tall stature crop regulates the availability of light on under storied crop (faruque et al., 2006). in bangladesh small farmers constitute 79.4% of our farming community and their cultivated lands are shrinking day by day (moa, 2014). in that context, intercropping is one of the viable technology to ensure efficient utilization of their resources for increased production and family income. intercropping offers the possibility of yield 2 ali et al. advantage relative to sole cropping through yield stability and improved yield in tropical and subtropical areas (nazir et al., 2002; malik et al., 2002; bhatti et al., 2005). brinjal is a long duration (160-180 days) and wide spaced (80 cm × 60 cm) crop. so, there is a great possibility to cultivate minimum canopy spread herbaceous plant like onion and garlic in the inter row space of brinjal. onion or garlic can be cultivated together with brinjal as they have different growth habit and duration. productivity can be increased through intercropping of these two crops. farmers can be benefited economically by proper utilization of the resources as well as contributing to food security and nutritional aspect. on the other hand, onion and garlic is the high value spices crop that market value always remains high (onion around 40 to 50 tk kg−1 and garlic around 100 to 120 tk kg−1) and they have also repellent character which may help in control brinjal shoot and fruit borer. so, there is a great possibility to cultivate minimum canopy spread herbaceous plant like onion and garlic in the inter row space of brinjal. productivity can be increased through intercropping of these crops. however, the literature regarding onion-brinjal and garlic-brinjal intercropping is very scarce. keeping this view in mind, the experiment was undertaken to find out suitable intercrop combination of onion and garlic with brinjal for increasing total productivity, economic return and maximize land utilization through intercropping system. materials and methods a field experiment was conducted at agronomy research field of bangladesh agricultural research institute, gazipur during rabi season of 2019-20 and 2020-21. the soil was silty clay loam with ph 6.3 belonging to agro ecological zone (aez) 28. the treatments were: t1= brinjal normal row (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal normal row (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal normal row (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal normal row (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal (80 cm × 60 cm) 100%, t6= sole onion (15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100%. the trial was set up in randomized complete block design with three replications. the unit plot size was 3.2 m × 4.2 m. the sole crop of brinjal and intercropped treatments were fertilized with cowdung 5 t ha-1 and 140-41-120-18-3-1.5 kg ha-1 of n-p-k-s-zn-b in the form of urea, triple super phosphate, murate of potash, gypsum, zinc sulphate and boric acid, respectively. for sole brinjal and intercrop, except n and k, full amount of all other fertilizer were applied in pit before 1 week of transplanting brinjal seedling. n and k were applied in three equal splits at 21, 40 and 60 days after transplanting (dat) of brinjal seedling as ring method followed by irrigation. sole onion and garlic were fertilized with 105-60-144-32-3.5-2.1 kg ha-1 of n-p-k-s-zn-b and 135-57-105-50-4.0-4 kg ha-1 n-p-ks-zn-b in the form of urea, triple super phosphate, murate of potash, gypsum, zinc sulphate and boric acid, respectively. for onion and garlic half n, k and all other fertilizers were applied at the time of final land preparation. rest n and k were applied in two equal splits at 25 dat and 50 dat under moist soil condition and mixed thoroughly with the soil as soon as possible for better utilization (frg, 2018). brinjal (var. bari begun-8) as base crop and onion (var. bari piaz-4) and garlic (var. bari roshun-4) were used as intercrops in this study. the sole crop of brinjal was planted at a spacing of 80 cm × 60 cm. in intercropping system four rows of onion, three rows of onion, four rows of garlic and three rows of garlic were intercropped in between two rows of brinjal. after establishment of brinjal seedling (12 dat) onion seedling and garlic cloves were transplanted/planted as per treatments. brinjal (thirty days old seedling) was transplanted on 29 november, 2019 and 10 december, 2020. onion seedling and cloves of garlic was transplanted/planted on 11 december, 2019 and 23 december, 2020, respectively. brinjal was harvested four times and it was harvested in 2020 on 12 march, 23 march, 18 april, 7 may and in 2021 harvested on 25 march, 7 april, 21 april, and 12 may. both onion and garlic were harvested on 16 april, 2020 and 21 april, 2021, respectively. five irrigations were done in the intercropping onion and garlic with brinjal under different planting system 3 experimental field. first was applied at just after brinjal transplanting. second, third, fourth and fifth irrigation were applied at 10, 45, 60 and 90 dat of brinjal seedling. weeding was done as per requirement. sex pheromone trap were used for controlling of brinjal shoot and fruit borer at active vegetative, fruit setting and fruit developing stage. light availability or photo synthetically active radiation (par) was measured by par ceptometer (model – lp-80, accu par, decagon, usa). the par was measured at 5-day intervals from 25 to 90 dat of onion seedling/ dap of garlic cloves at around 11:30 am to 13:00 pm. four readings each of parinc and part were recorded at different spots of each plot. the proportion of intercepted par (parint) was calculated using the following equation and expressed in percentage: light availability {part (%)} = part parinc × 100 where, parinc = incident par, part = transmitted par, parint = intercepted par. the yield component data of brinjal was taken from 10 randomly selected plants prior to harvest from each plot. yield data of brinjal, onion and garlic were recorded plot wise. yield and yield contributing characters were recorded and pooled data analyzed statistically and mean separations were done by lsd test at 5% level of significance. brinjal equivalent yield (bey) was converted by converting yield of intercrops on the basis of present market price of individual crop following the formula: bey = yield of intercrop brinjal + brinjal of price pi × yi where, yi = yield of intercrops (onion/garlic) and pi = price of intercrop (onion/garlic). land equivalent ratio (ler) was determined from the yield data of the crops according to mian (2008). ler = biyb bsy + riyc rsyc biyb = intercrop yield of brinjal bsy = sole crop yield of brinjal riyc = intercrop yield of component crops (onion/ garlic). rsyc = sole crop yield of component crops (onion/ garlic). results and discussion light availability in both the year (2019-20 and 2020-21), irrespective of treatments, availability of light on onion and garlic canopy was almost 100% at earlier growth stage 30 dat of onion seedling and 30 days after planting of garlic cloves and it decrease with the increase of shade produced by brinjal canopy over the time up to onion and garlic harvest (fig. 1). in both the years, throughout the growing period of onion and garlic the maximum light availability was observed in t6 (sole onion) and t7 (sole garlic) treatments. however, among the intercropping treatments the maximum light availability was observed in t4 treatment (3 row garlic 43% in between two row of brinjal 100%) followed by t3 treatment (4 row garlic 57% in between two row of brinjal 100%). the minimum light availability was observed in t1 treatment (4 row onion 57% in between two row of brinjal 100%) followed by t2 treatment (3 row onion 43% in between two row of brinjal 100%) up to onion and garlic harvest. among all treatments, the maximum light availability was observed in t6 (sole onion) and t7 treatments (sole garlic) treatment (fig.1). light availability was more in brinjal + garlic intercropping system than brinjal + onion intercropping system throughout the growing period. 4 ali et al. fig.1. light availability on onion and garlic in brinjal + onion/ garlic intercropping system (2019-20 and 2020-21) yield and yield contributing characters of brinjal number of fruits plant−1, single fruit weight, fruit length, fruit diameter and yield of brinjal was significantly varied due to intercropping of onion and garlic with brinjal and sole crop of brinjal except plant height (table 1). table 1. fruit yield and yield attributes of brinjal under sole and intercropping system treatment plant height (cm) fruit plant−1 (no.) single fruit weight (g) length of fruit (cm) fruit diameter (cm) fruit yield (t ha−1) t1 90.95 19.85 72.17 19.47 3.48 14.75 t2 93.82 22.67 78.64 21.98 4.03 16.12 t3 96.37 23.12 82.65 20.88 3.84 16.83 t4 99.39 25.84 86.99 23.38 4.19 19.94 t5 104.01 28.08 94.74 25.27 4.33 22.48 lsd (0.05) ns 2.89 9.87 2.64 0.17 2.99 cv (%) 5.69 6.42 6.32 6.31 7.37 8.82 note: t1= brinjal normal row (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal normal row (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal normal row (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal normal row (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal normal row (80 cm × 60 cm) 100%, t6= sole onion (15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100%. significantly the maximum number of fruits plant−1 (28.08), single fruit weight plant−1 (94.74 g), highest fruit length (25.27 cm) and fruit diameter (4.33 cm) and fruit yield (22.48 t ha−1) were recorded in sole planting of brinjal. in case of intercropping combination, the maximum number of fruits plant−1 (25.84), single fruit weight plant−1 (86.99 g), highest fruit length (23.38 cm), fruit diameter (4.19 cm) and fruit yield (16.83 t ha−1) was recorded in t4 treatment (brinjal normal row 100% + 3 row garlic 43%). similar trend was found in case of onion with brinjal intercropping combination the maximum number of fruits plant−1 (22.67), single fruit weight plant−1 (78.64 g), highest fruit length (21.98 cm), fruit diameter (4.03 cm) and fruit yield (16.12 t ha−1) was recorded in t2 treatment (brinjal normal row 100% + 3 row onion 43%). the lowest number of fruit plant−1 (19.85 in onion and 23.12 in garlic), single fruit weight (72.17 g in onion 0 20 40 60 80 100 120 30 45 55 65 80 95 t1 = bnr + 4 row o t2 = bnr + 3 row o t3 = bnr + 4 row g t4 = bnr + 3 row g t6 = sole o t7 = sole g days after transplanting l ig h t a va ila b ili ty ( % ) 2019-2020 0 20 40 60 80 100 120 30 45 55 65 80 95 t1 = bnr + 4 row o t2 = bnr + 3 row o t3 = bnr + 4 row g t4 = bnr + 3 row g t6 = sole o t7 = sole g 2020-2021 days after transplanting l ig h t a va ila b ili ty ( % ) intercropping onion and garlic with brinjal under different planting system 5 and 82.65 cm in garlic), fruit length (19.47 cm in onion and 20.88 cm in garlic), fruit diameter (3.48 cm in onion and 3.84 cm in garlic) and fruit yield (14.75 t ha−1 in onion and 16.83 t ha−1 in garlic) were obtained from t1 and t3 treatments (brinjal normal row (80 cm × 60 cm) 100% + 4 row onion/garlic (15 cm × 10 cm) 57%). it was apparent that all the yield contributing characters and yields in the intercrops increased gradually with the decreased of garlic population. this might be due to competition between brinjal and garlic crop for moisture, light and nutrients. islam et al., (2014) also not find any significant difference in yield and yield attributes of brinjal due to intercropping of leafy vegetables/legumes i.e. growing of the intercrops in interspaces between brinjal rows did not affect the base crop. yield of onion and garlic the number of plant m−2, plant height, single bulb weight and bulb yield of onion and garlic was markedly differed by intercrop combination (table 2). the highest number of plant m−2 of onion (69.59 m−2) was obtained from t6 treatment (sole onion). among the intercropping situation in case of onion, the highest number of plant m-2 (38.59 m−2) of onion was obtained from t1 treatment (brinjal 100% + 4 row onion 57%) and the lowest number of plant m-2 (27.59 m2) was recorded in t4 treatment (brinjal 100% + 3 row garlic 43%). the highest plant height (50.45 cm) and single bulb weight (60.90 g) was recorded in t2 treatment (brinjal 100% + 3 row onion 43%) and the lowest plant height (46.42 cm) and single bulb weight (55.08 g) was obtained from t1 treatment (brinjal 100% + 4 row onion 57%). on the other hand, in case of garlic the similar trend also was observed. the highest number of plant m−2 of garlic (36.26 m−2) was obtained from t3 treatment (brinjal 100% + 4 row garlic 57%) and the lowest number of plant m−2 (27.59 m-2) was recorded in t4 treatment (brinjal 100% + 3 row garlic 43%). the highest plant height (43.65 cm) and single bulb weight (12.96 g) was recorded in t4 treatment (brinjal 100% + 3 row garlic 43%) and the lowest plant height (41.82 cm) and single bulb weight (10.16 g) was obtained from t3 treatment (brinjal 100% + 4 row garlic 57%). the highest bulb yield of onion (15.68 t ha−1) was obtained from t6 treatment (sole onion) and the highest bulb yield of garlic (7.25 t ha−1) was obtained from t7 treatment (sole garlic). among the intercropping situation the maximum bulb yield of onion (8.66 t ha−1) was recorded in t1 treatment (brinjal 100% + 4 row onion 57%) and the lowest bulb yield (6.23 t ha−1) was obtained from t2 treatment ((brinjal 100% + 3 row onion 43%). similar trend also was observed in case of garlic. the highest bulb yield of garlic (3.92 t ha−1) was recorded in t3 treatment (brinjal 100% + 4 row garlic 57%) and the lowest bulb yield (2.91 t ha−1) was obtained from t4 treatment (brinjal 100% + 3 row garlic 43%). the higher bulb yield in onion and garlic was attributed to maximum number of plant m-2. faruque et al. (2006) also reported similar result. table 2. bulb yield and yield components of onion and garlic under sole and intercropping system treatments plant m-2 plant height (cm) single bulb weight (g) bulb yield (t ha-1) t1 38.59 46.42 55.08 8.66 t2 27.92 50.45 60.90 6.23 t3 36.26 41.82 10.16 3.92 t4 27.59 43.65 12.96 2.91 t6 69.59 53.74 61.88 15.68 t7 65.92 45.15 13.70 7.25b lsd (0.05) 4.60 4.86 5.01 1.55 cv (%) 5.70 5.70 7.69 11.42 note: t1= brinjal normal row (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal normal row (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal normal row (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal normal row (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal normal row (80 cm × 60 cm) 100%, t6= sole onion ((15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100%. 6 ali et al. brinjal equivalent yield brinjal equivalent yield was expressed in total productivity. brinjal equivalent yields were higher in all the intercrops (30.14 to 36.42 t ha-1) than the sole crop of brinjal (22.48 t ha-1) indicated higher productivity than sole cropping (table 3). in intercrop combination the highest brinjal equivalent yield (36.42 t ha-1) was recorded in t3 treatment (4 row garlic 57% in between two row of brinjal 100%) which was followed by t4 treatment (34.46 t ha-1) (3 row garlic 43% in between two row of brinjal 100%) and t1 treatment (34.22 t ha-1) (4 row onion 57% in between two row of brinjal 100%). the total productivity were also increase of 34.05-62.00% over sole brinjal. ahmed et al. (2013) also reported that intercrop combination always increase the equivalent yield. land equivalent ratio the highest land equivalent ratio (1.29) was recorded in t3 treatment (4 row garlic 57% in between two row of brinjal 100%) and t4 treatment (3 row garlic 43% in between two row of brinjal 100%) intercropping system (table 3). the land equivalent ratio (ler) of different crop combinations ranged from 1.11 to 1.29 indicating that land utilization was increased 11 to 29% through intercropping. the mean values of ler (more than one) in all intercropping treatments revealed that land was more efficiently utilized under intercropping than that of sole cropping of brinjal, onion and garlic. nazir et al. (2002) also reported that intercrop combination always increase the land equivalent ratio (ler). table 3. brinjal equivalent yield (bey), land equivalent ratio (ler) and % increase of bey over sole brinjal in brinjal + onion/garlic intercropping system treatments bey (t ha-1) % increase of bey over sole brinjal ler t1 34.22 52.23 1.21 t2 30.14 34.05 1.11 t3 36.42 62.00 1.29 t4 34.46 53.31 1.29 t5 22.48 1 note: t1= brinjal normal row (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal normal row (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal normal row (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal normal row (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal normal row (80 cm × 60 cm) 100%, t6= sole onion (15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100%. cost benefit analysis cost and return analysis is an important tool to evaluate the economic feasibility of intercropping system and monetary advantage was evaluated according to shah et al. (1991). benefit cost analysis of brinjal + onion/garlic intercropping system have been presented in table 4. intercropping combination of onion and garlic with brinjal showed higher monetary return than sole crop. among the intercropping situation the maximum gross return (tk.7,28,333 ha-1) was recorded from t3 treatment (4 row garlic 57% in between two row of brinjal 100%). this intercropping combination also gave the maximum gross margin (tk. 4,76,596 ha-1) and benefit cost ratio (2.89) followed by t1 treatment (2.78) (4 row onion 57% in between two row of brinjal 100%) and t4 treatment (2.75) (3 row garlic 43% in between two row of brinjal 100%). the minimum gross return (tk. 6,02,708 ha-1), gross margin (tk.3,58,467 ha-1) and bcr (2.47) were obtained from t2 treatment (3 row onion 43% in between two row of brinjal 100%). the results revealed that intercropping increased productivity and returns were consistent with the earlier reports of yield advantage of crop mixture compared to monoculture (akhteruzzaman et al., 1991, islam et al., 2012 and ahmed et al., 2013). intercropping onion and garlic with brinjal under different planting system 7 table 4. cost and return analysis of sole brinjal and brinjal+ onion/ garlic intercropping system treatments gross return (tk. ha−1) cost of production (tk. ha-1) gross margin (tk. ha-1) benefit cost ratio (bcr) t1 6,84,442 2,46,637 4,37,805 2.78 t2 6,02,708 2,44,241 3,58,467 2.47 t3 7,28,333 2,51,737 4,76,596 2.89 t4 6,89,267 2,50,241 4,39,026 2.75 t5 4,49,633 2,29,851 2,19,782 1.96 price: brinjal: tk. 20 kg−1, onion: tk. 45 kg−1, garlic: tk. 100 kg−1, note: t1= brinjal normal row (80 cm × 60 cm) 100% + 4 row onion (15 cm × 10 cm) 57%, t2= brinjal normal row (80 cm × 60 cm) 100% + 3 row onion (15 cm × 10 cm) 43%, t3= brinjal normal row (80 cm × 60 cm) 100% + 4 row garlic (15 cm × 10 cm) 57%, t4= brinjal normal row (80 cm × 60 cm) 100% + 3 row garlic (15 cm × 10 cm) 43%, t5= sole brinjal normal row (80 cm × 60 cm) 100%, t6= sole onion (15 cm × 10 cm) 100%, t7= sole garlic (15 cm × 10 cm) 100%. conclusion from two years results revealed that all intercropping combination showed higher productive and profitable than sole brinjal. 4 row garlic (15 cm × 10 cm) 57% in between two row of brinjal (80 cm × 60 cm) 100% intercropped combination was found agronomically feasible and economically profitable. references ahmed, f., m.n. islam, m.s. alom, m.a.i. sarker and m.a. mannaf. 2013. study on itercropping leafy vegetables with okra (abelmoschus esculentus l.). bangladesh j. agril. res. 38(1): 137-143. akhteruzzaman, m and m.a. quayyum. 1991. intercropping of maize with three varieties of groundnut at two levels of plant population. bangladesh j. agril. sci. 18(1): 39-44. alom, m.s., b.l. nag, m.n. islam, f. ahmed and s. akter. 2013. performance of different crop species with pointed gourd (trichosanthes dioicaroxb.). bangladesh j. agril. res. 38(3): 523-529. bhatti, i.h. 2005. agro-physiological studies on sesame-legume intercropping system in different geometric arrangements. ph. d. thesis, department of agronomy, university of agriculture faisalabad, pakistan. faruque, a., m.a. rahaman, m.a.h.s. jahan, m. ahmed and m.a. khyer. 2006. effect of different planting systems in maize/spinach-red amaranth intercropping. bangladesh j. agric. and environ. 2(2): 6976. frg. 2018. fertilizer recommendation guide, bangladesh agricultural research council (barc), farm gate, dhaka 1215. pp. 102-223 and 109-110. islam, m.r., m.a.k. mian and m.t. rahman. 2012. suitability of intercropping sesame with mukhikachu. bangladesh j. agril. res. 37(4): 625-634. islam, m.r., m.t. rahman, m.f. hossain and n. ara. 2014. fesibility of intercropping leafy vegetables and legumes with brinjal. bangladesh j. agril. res. 39(4): 685-692. malik, m.a., m.f. saleem, m. sana and a. aziz. 2002. agro economic expression of different relay crops after rice harvest under conventional and zero tillage. int. j. agric. biol. 4: 277-278. mian, m.a.k. 2008. performance of maize oriented cropping patterns under different nutrient management. ph. d. dissertation. dept. agron. bangladesh agril. univ., mymensingh. pp. 31-137. moa. 2014. ministry of agriculture, hand book of agricultural statistics, december 2007. government of the peoples republic of bangladesh. http://www.moa.gov.bd/ statistics/ statistics.htm. nazir, m.s., a. jabbar, i. ahmad, s. nawaz and i.h. bhatti. 2002. production potential and economics of intercropping in autumn-planted sugarcane. int. j. agric. biol. 4: 140-142. shah, n.h., p.k. koul, b.a. khanday and d. kachrov. 1991. production potential and monetary advantage index of maize intercropped with different grain legumes. indian j. agron. 36(1): 23-28. blank page microsoft word 1. baj-450e bangladesh agron. j. 2024, 26(2): 1-6 nutrient requirement of advanced olitorius breeding line o-0512-6-2 for maximum growth and yield a. sultana*, j. ferdous, s.a. jui, n. tasnim and m.a. alim agronomy division, bangladesh jute research institute, manik mia avenue, dhaka, bangladesh *corresponding author, email: oni.abida@gmail.com (received: 15 january 2023, accepted: 20 november 2023) keywords: fiber crop, nutrient, growth, fiber yield, olitorius breeding line abstract the research work was conducted at jute agriculture experimental station (jaes) manikganj and jute agriculture regional station (jars) faridpur of bangladesh. the present study aimed at determining the nutritional requirement for optimum growth and yield of an advanced olitorius breeding line of o-0512-6-2 in bangladesh. the experiment was laid out in rcbd with 10 treatments having three replications during the year 2019, 2020 and 2021. the results indicated significant effect on yield and yield contributing characters over control with different fertilizer (npks) levels of advanced olitorius breeding line of o-0512-6-2. the highest number of plant height, base diameter, green weight with leaves and without leaves was observed by the treatment t3 (n100p10k25s20) which is statistically significant. the highest fiber yield (2.75 t ha−1) and stick yield (6.50 t ha−1) at manikganj and highest fiber yield (2.58 t ha−1) and stick yield (6.09 t ha–1) at faridpur was also obtained by the combined dose of n100p10k25s20 (t3) kg ha−1. therefore, this combination n100p10k25s20 kg ha−1 seemed to be optimum for maximum growth and yield of advanced olitorius breeding line of o-0512-6-2. introduction jute is an eco-friendly and the major cash crop in bangladesh. bangladesh produces 33 % of the total worldwide production of jute. bangladesh's top priority is to improve jute fiber yield and quality. bangladesh generated jute fiber on an average of 7.45 lakh ha of land per year (bbs, 2021). jute holds an important position in the industrial sector of the economy of bangladesh (islam and ali, 2017). however, from 2010-2011 and onwards, the area and development grew dramatically as people became more environmentally conscious and shifted to natural fibers to avoid harmful effects of synthetic fibers on the environment. as a result, demand for jute fiber has risen in recent years, both domestically and internationally. jute fiber is produced mainly from white jute (corchorus capsularis) and tossa jute (corchorus olitorius). demand of jute fiber is being increased in the recent years both in home and abroad (islam and ali, 2018). jute fiber is used to make many different sorts of bags, wools, ropes, sacks, and coverings. the superior quality jute fiber is used for making carpets, twine, curtains, cloth etc. jute sticks, the byproduct, are used as fuel, fencing and raw materials for paper pulp and hardboard. jute leaves, which are high in vitamins, carotenoids, calcium, potassium, and dietary fibres, are used in soups and folk medicine to cure fevers, chronic cystitis, colds, and tumours. aside from its diverse uses, cultivation of this crop improves soil fertility by supplying a large quantity of green biomass through leaves, twigs, and thinned out plant, which includes a significant number of macro and micro nutrients (singh et al., 2015). bangladesh jute research institute (bjri) has been developed some tossa varieties/ strains. the importance of macronutrients (n, p, k and s) on the growth, yield and quality of fiber crops is well established. judicial application of npk and s may increase the yield of a variety. the importance of n, p, k and s on the growth, yield and quality of fiber crops is well established (ali et al., 2017a, 2017b). balanced nutrition is a crucial component of developing plants and comprises providing the plant with enough of the vital minerals n, p, k, mg, ca etc. (senjobi et al., 2013). determination of nutrients rate for the new varieties/ strains are also pre-requisite for final release. yet this fertilizer plays an 2 sultana et al. important role to increase the fibre growth and yield. it is necessary to find a fertilizer combination which is economically profitable and at the same time gives maximum yield and yield potential. so, an experiment has been undertaken to observe the effects of macronutrients (n, p, k and s) on growth, yield and quality of the advanced tossa jute breeding line o-0512-6-2. materials and methods in bangladesh, the experiment was carried out at jute agriculture experimental station (jaes) manikganj and jute agriculture regional station (jars) faridpur of bangladesh during 20192021. the experiment was laid out in randomized complete block design (rcbd) with 10 treatments of npk and s (kg ha⁻1) having three replications. total 10 treatments combination along with a control distributed randomly in each plot as one replication. the dimension of unit plot was (2.1 m×2 m) having 1 m space between plots, blocks and around the field. there was 20 cm deep drain around each block and plot. the land was well prepared and fertilizers were applied as per treatments. the following treatments combinations were used in the experiment: t1: n0p0k0s0 t6: n100p15k30s30 t2: n75p10k25s20 t7: n100p15k30s40 t3: n100p10k25s20 t8: n100p20k30s20 t4: n125p10k25s20 t9: n100p20k30s30 t5: n100p15k30s20 t10: n125p20k35s40 required amount of n, p, k and s fertilizers were applied in the form of urea, tsp, mop and gypsum. the experiment was sown on first week of april and harvested first week of august. half urea and total amount of tsp, mop and gypsum were incorporated to the experimental plot as per treatment design at the time of final land preparation. remaining half of urea was top dressed at 45 days after sowing (das). table 1. soil initial analysis report at the experimental plot of manikganj ph om total n (%) phosphorus (µg g−1) potassium (meq/100 g) sulfur (µg g−1 soil) 6.7 2.8 0.094 10 0.13 7.0 neutral medium very low low low very low table 2. soil initial analysis report at the experimental plot of faridpur ph ec (ds m−1) om nitrogen (%) phosphorus (µg g−1 soil) potassium (meq/100 g) sulfur (µg g−1 soil) 7.4 12.71 1.8 0.088 6.28 0.06 9.91 weeding, thinning, insect pest and disease management were done in time. plant population, plant height, base diameter, green weight with leaves, green weight without leaves, fiber yield and stick yield were recorded from each plot. all collected data were analyzed statistically following the anova technique and the means were adjusted by dmrt (gomez and gomez ,1984). results and discussion nitrogen, phosphorus, potassium and sulfur are the main essential macronutrients for most of the biological process in a plant. their individual effects and interactions on fiber plants were showed in many studies (maity et al., 2007). fiber yield and yield contributing characters were affected by different treatment combinations. this experiment used 10 treatment combinations. nutrient requirement of advanced breeding line for maximum growth 3 in manikganj, the highest plant height (3.04 m), base diameter (17.42 mm), green weight with leaves (39.02 t ha−1) and green weight without leaves (35.81 t ha−1) were observed with the application of treatment t3 (n100p10k25s20). (table 3) significant effect of increasing dose of fertilizer application on fiber yield and stick yield was also observed. table 3. yield and yield contributing characters of advanced olitorius breeding line o-0512-6-2 with different levels of npk and s at manikganj treatment plant population m2 plant height (m) base diameter (mm) green weight with leaves (t ha−1) green weight without leaves (t ha−1) t1:n0p0k0s0 28.33 2.66bc 15.79ab 31.26bc 28.97b t2:n75p10k25s20 27.69 2.80abc 16.11ab 28.72c 27.19b t3:n100p10k25s20 32.81 3.04a 17.42a 39.02a 35.81a t4:n125p10k25s20 27.93 2.87abc 16.05ab 33.29ab 31.03a t5:n100p15k30s20 27.38 2.91ab 16.13ab 32.50bc 30.83ab t6:n100p15k30s30 31.00 2.94ab 17.06ab 28.80bc 28.21b t7:n100p15k30s40 39.26 2.88abc 16.02ab 29.16bc 28.82b t8:n100p20k30s20 32.46 2.83abc 15.78ab 33.12bc 29.04b t9:n100p20k30s30 33.81 2.86abc 15.90ab 32.85bc 28.91b t10:n125p20k35s40 35.04 2.61c 15.42b 34.60ab 32.59ab cv (%) 14.47 2.64 6.71 10.59 12.18 significantly highest fiber yield (2.75 t ha−1) and stick yield (6.50 t ha−1) was observed with the treatment combination of t3 (n100p10k25s20) (fig. 1, 2). fig. 1. fiber yield of advanced olitorius breeding line o-0512-6-2 using different chemical fertilizer treatments. each datum was calculated from three independent experiments in manikganj. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 fi br e yi el d (t ha −1 ) treatments 4 sultana et al. fig. 2. stick yield of advanced olitorius breeding line of o-0512-6-2 using different chemical fertilizer treatments. each datum was calculated from three independent experiments in manikganj. in case of plant population, the highest number of plant (39.26) was observed with the application of treatment t7 (n100p15k30s40) which is statistically non-significant. in faridpur, the effect of different doses of fertilizer application on advanced breeding line o-0512-6-2 growth and yield metrics were observed. the plant height (2.99 m), highest base diameter (13.88 mm), green weight with leaves (33.18 t ha−1) and green weight without leaves (29.45 t ha−1) were observed by the treatment combination of t3 (n100p10k25s20) (table 4). table 4. yield and yield contributing characters of advanced olitorius breeding line o-0512-6-2 with different levels of npk and s at faridpur treatment plant population m-2 plant height (m) base diameter (mm) green weight with leaves (t ha−1) green weight without leaves (t ha−1) t1:n0p0k0s0 18.33 2.47 12.23ab 21.47bc 17.32b t2:n75p10k25s20 21.33 2.87 11.45b 26.72c 21.63b t3:n100p10k25s20 24.34 2.99 13.88a 33.18a 29.45a t4:n125p10k25s20 27.93 2.99 12.67ab 31.47ab 26.27a t5:n100p15k30s20 27.23 3.10 12.67ab 27.33bc 23.03ab t6:n100p15k30s30 21.20 2.82 12.70ab 24.13bc 19.42b t7:n100p15k30s40 29.26 2.94 13.27ab 25.63bc 21.55b t8:n100p20k30s20 26.26 3.16 13.68a 26.88bc 21.33b t9:n100p20k30s30 23.31 3.08 13.08ab 26.67bc 22.47b t10:n125p20k35s40 24.04 3.17 12.69ab 29.18ab 27.89ab cv (%) 14.47 7.44 9.02 8.52 10.32 significant effect of additional fertilizer application on fiber and stick yield was also observed. the highest fiber yield (2.58 t ha−1) and stick yield (6.09 t ha−1) which was statistically significant and obtained by treatment t3 (n100p10k25s20) (fig. 3, 4). so, the combined dose of npk and s 100-10-25-20 kg ha−1 is a suitable dose for the cultivation of advanced breeding line o-0512-6-2 for maximum growth and production. these results are strongly supported by the previous research results (sarker et al., 2000; ali et al., 2017). 0 1 2 3 4 5 6 7 8 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 st ic k yi el d (t ha −1 ) treatments nutrient requirement of advanced breeding line for maximum growth 5 fig. 3. fiber yield of advanced olitorius breeding line of o-0512-6-2 using different chemical fertilizer treatments. each datum was calculated from three independent experiments in faridpur. fig. 4. stick yield of advanced olitorius breeding line of o-0512-6-2 using different chemical fertilizer treatments. each datum was calculated from three independent experiments in faridpur. conclusion the use of combined chemical fertilizers had a considerable favorable impact on all yield contributing characteristics as well as yield. the present study revealed the positive impacts of combined dose of npks on the fiber yield and yield component of advanced olitorius breeding line o-0512-6-2 in both locations. the combined dose of n100p10k25s20 is a suitable dose for the cultivation of advanced olitorius breeding line of o-0512-6-2 in bangladesh. references ali, m.s., m.m. hoque, m.n. gani and m.m. islam. 2017. variation in inorganic fertilizer is an important regulator of yield potential in bjri mesta-3. am. j. environ. eng. sci. 4(6): 78-84. ali, m.s., m.n. gani and m.m. islam. 2017a. nutrient management on growth and yield of bjri tossa pat 6. nutr. food technol. 3(3): 1-5. ali, m.s., m.n. gani and m.m. islam. 2017b. efficiency of bjri kenaf-4 yield under different fertilizer levels. american j. agric. for. 5(5): 145-149. bbs (bangladesh bureu of statistics). 2021. statistical yearbook of bangladesh. bangladesh bureau of statistics, ministry of planning, government of the peoples republic of bangladesh. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 fi be r y ie ld (t ha −1 ) treatments 0 1 2 3 4 5 6 7 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 st ic k yi el d (t ha −1 ) treatments 6 sultana et al. gomez, k.a. and a.a. gomez .1984. statistical procedures for agricultural research. 2nd edn, wiley, new york. pp. 13-175. islam, m.m. and m.s. ali. 2018. industrial research advances of jute in bangladesh. int. j. agric. biosyst. eng. 3(1): 1-9. islam, m.m. and m.s. ali. 2017. economic importance of jute in bangladesh: production, research achievements and diversification. int. j. econ. theor. appl. 4(6): 45-57. maity, s.k., s. karmakar and p.k. mukherjee. 2007. response of ramie (boehmeria nivea) cultivars to nutrient management and planting methods. indian j. agron. 52(3): 257-260. sarker, a.k. and p.k. bandopaddhay. 2000. effect of potassium, boron and crop age on the yield and quality of white jute (corchorus capsularis). j. interacademicia. 4(1): 73-77. senjobi, b.a., s.j. akinsete, o.t. ande and o.a. ademoye. 2013. sandy soil improvement using organic materials and mineral fertilizer on the yield and quality of jute plant (corchorus olitorius). j. bio. life sci. 4(1): 220-233. singh, s.r., d.k. kundu, m.k. tripathi, p. dey, a.r. saha, m. kumar and b.s. mahapatra. 2015. impact of balanced fertilization on nutrient acquisition, fibre yield of jute and soil quality in new gangetic alluvial soils of india. appl. soil ecol. 92: 24-34. bangladesh agron. j. 2022, 25(2): 109-117 effect of nitrogen doses in boro rice grown with variable levels of floating duckweed a. hossain1, h.m.m.t. hossain2, a.k.m.r. amin2, and m.h. mahmud3 1bangladesh institute of nuclear agriculture, 2department of agronomy, sau dhaka-1207, bangladesh, 3project implementation unit-barc, national agricultural technology program-phase-ii project, barc, dhaka corresponding e-mail: alif.bina21@yahoo.com (received: 11 december 2022, accepted: 29 january 2023) keywords: nitrogen dose, boro rice, floating duckweed, yield abstract an experiment was carried out at the agronomy research farm of sher-e-bangla agricultural university, dhaka during the period from november 2018 to june 2019 to study the nitrogen requirement of boro rice grown with floating duckweed. the experiment was laid out in a factorial randomized complete block design with three replications. the treatments were duckweed: viz. d0 = control (0 g duckweeds m-2), d1 = 200 g duckweeds m-2, d2 = 400 g duckweeds m-2 and d3 = 600 g duckweeds m-2) and nitrogen treatment: n1 = 45 kg n ha-1, n2 = 90 kg n ha-1 and n3 = 180 kg n ha-1). different doses of duckweeds showed significant influence on most of the parameters of which d2 (400 g duckweeds m-2) treatment the best performance on growth and yield parameters of rice. among different doses of nitrogen, n2 (90 kg n ha-1) gave the best results on growth and yield parameters of rice. in case of combined effect, d2n2 showed the highest number of tillers hill-1 (16.40), dry weight hill-1 (48.97 g), number of effective tillers hill-1 (14.73) and number of grains panicle-1 (189.50). this treatment combination also showed the highest number of filled grains panicle-1 (183.90), panicle length (25.83 cm), 1000 -grain weight (25.13 g), seed yield (7.24 t ha-1), straw yield (8.47 t ha-1), biological yield (15.71 t ha-1) and harvest index (46.09%). on the other hand, d0n3 gave the least results on these parameters. findings revealed that application of 400 g duckweeds m-2 with 90 kg n ha-1 showed the superiority over other treatment combinations to produce higher grain yield of boro rice. introduction globally, agriculture is currently facing unprecedented challenges for nourishing the increasing population without devastating the environment (chen et al., 2014; zhang et al., 2015). in bangladesh, area covered by rice was 11.39 million hectares with the production of 35.05 million metric tons (bbs, 2018). boro rice is one of the most important rice crops for bangladesh with respect to its high yield and contribution to rice production. nitrogen is a major essential plant nutrient and a key input for increasing crop yield. rice plants require a large amount of nitrogen at the early and mid tillering stage to maximize the number of panicles. optimum dose of nitrogen fertilization plays a vital role in growth and development of rice plant. rice grain yield was recorded significantly highest between ranges of 90-250 kg ha-1 nitrogen application (marazi et al., 1993; daniel and wahab, 1994; bali et al., 1995). a significant increase in tillering (hussain et al., 1989; meena et al., 2003) with increase in nitrogen supply was observed. gm is generally eco-friendly, economically viable and renewable for sustainable agriculture. 110 hossain et al. over the last 40 years, research regarding duckweed mainly focused on phytoremediation and nutrient recovery from wastewater and for animal feedstock and the production of biofuels, due to its high growth rate, high biomass yield, excellent nutrient uptake ability, and tolerance to high nutrient levels (cheng et al., 2002; mohedano et al., 2012). so far, few studies have examined the influence of duckweed on nh3 volatilization (zimmo et al., 2003; li et al., 2009; sun et al., 2015), and only li et al. (2009) reported that duckweed cover combined with urea could effectively increase rice yield at 90 and 180 kg n ha−1. meanwhile, the current chinese agriculture systems are highly fertilized, few studies have comprehensively accessed the n balance of urea combined with duckweed in current intensive rice cropping systems. therefore, a field experiment was conducted with the aims to increasing n use efficiency with floating duckweed on boro rice yield. materials and methods the experiment was carried out at sher-e-bangla agricultural university farm, dhaka, bangladesh during the period from november 2018 to june 2019. the geographical location of the site is 90°33´e longitude and 23°77´n latitude which belongs to “the modhupur tract”, aez-28. the experiment was laid out in factorial randomized complete block design (rcbd) with three replications. the experiment was comprised of duckweed at four levels, d0 = control (0 g duckweeds m-2), d1 = 200 g duckweeds m-2, d2 = 400 g duckweeds m-2 and d3 = 600 g duckweeds m-2, and nitrogen at three levels, n1 = 45 kg n ha-1, n2 = 90 kg n ha-1 and n3 = 180 kg n ha-1. healthy seeds of boro rice var. brri dhan28 was used as test crop. after final preparation of land with recommended fertilizer dose, 40 days old seedlings with 25 cm × 15 cm spacing was maintained. after collection of duckweeds from sources those were kept in a cistern in research field for purification and refreshing. when field was ready then measured in several packets previously determined weight after water removal. duckweeds were introduced in the target plots after two days of planting seedlings. water level of plots maintained in below plots ridges to control duckweeds in desired plots. all intercultural and plant protection measures were taken to all the plots. the first plant height and number of tillers hill-1 were measured at 25 dat and continued up to harvest with 20 days interval. data on yield components were collected from the sample plants of each plot. the significant differences among the treatments were judged at 5% level of probability by using least significant difference (lsd) with a computer operated program named mstat-c. results and discussion plant height significant difference was found among the treatment on plant height of rice at all growth stages due to application of duckweed at different rates, different doses nitrogen and its combination (table 1). results revealed that the maximum plant height (23.19, 61.41 and 97.49 cm at 30, 60 dat and at harvest, respectively) was found from the treatment d2 which was statistically same with d1 at 60 dat but at harvest it was significantly different from other treatments. the lowest plant height (20.28, 52.82 and cm at 30, 60 dat and at harvest, respectively) was found from control treatment d0. the maximum plant height (23.06, 60.69 and 97.28 cm at 30, 60 dat and at harvest, respectively) was found from the treatment n3 which was statistically similar with n2 whereas the lowest plant height (20.21, 54.68 and 89.14 cm at 30, 60 dat and at harvest, respectively) was found from the treatment n1. the result obtained from the present study was followed by the findings of adhikari (2018) and chamely and islam (2015). the highest plant height (24.43, 63.99 and 100.90 cm at 30, 60 dat and at harvest, respectively) was found from the treatment combination of d2n3 whereas the lowest plant height (21.77, 55.59 and 92.73 cm at 30, 60 dat and at harvest, respectively) from the treatment combination of d0n1. effect of duckweed and nitrogen on growth and yield of boro rice 111 table 1. plant height and number of tillers hill-1 of rice as influenced by duckweed and nitrogen and their combination treatments plant height (cm) number of tillers hill-1 30 dat 60 dat at harvest 30 dat 60 dat at harvest effect of duckweed (d) d0 20.28 b 52.82 d 88.35 c 6.256 c 10.03 b 10.81 c d1 22.12 ab 59.78 a 94.29 b 7.333 b 13.09 a 14.44 ab d2 23.19 a 61.41 a 97.49 a 9.289 a 14.16 a 14.76 a d3 21.16 ab 56.78 c 92.86 b 6.978 bc 10.95 b 13.06 b lsd(0.05) 2.41 2.30 1.87 0.92 1.40 1.50 effect of nitrogen (n) n1 20.21 b 54.68 b 89.14 b 7.125 11.91 b 13.06 b n2 21.80 ab 57.72 ab 93.32 ab 7.875 13.60 a 14.89 a n3 23.06 a 60.69 a 97.28 a 7.392 10.66 c 11.85 b lsd(0.05) 2.08 5.45 7.92 ns 1.22 1.30 combined effect of duckweed and nitrogen d0n1 21.77 a-c 55.59 a-c 92.73 ab 6.00 e 9.913 e-g 10.22 de d0n2 19.94 bc 52.80 bc 88.30 ab 6.87 de 10.93d-g 12.41 b-d d0n3 19.14 c 50.08 c 84.03 b 5.90 e 9.253 g 9.800 e d1n1 22.18 a-c 60.67 a-c 94.77 ab 6.20 de 13.07b-d 14.27 ab d1n2 23.21 a-c 62.43 ab 98.11 ab 6.60 de 14.40 ab 15.99 a d1n3 20.96 a-c 56.23 a-c 89.98 ab 9.20 bc 11.80 c-f 13.07 bc d2n1 23.63 ab 61.46 ab 96.59 ab 9.77 b 14.19 a-c 14.54 ab d2n2 21.49 a-c 58.79 a-c 94.93 ab 11.43 a 16.17 a 16.40 a d2n3 24.43 a 63.99 a 100.9 a 6.67 de 12.13 b-e 13.33 bc d3n1 21.43 a-c 55.97 a-c 93.62 ab 6.53 de 10.47 e-g 13.20 bc d3n2 22.81 a-c 60.73 a-c 97.33 ab 6.60 de 12.91 -d 14.76 ab d3n3 19.24 c 53.63 a-c 87.63 ab 7.80 cd 9.46 fg 11.21 c-e lsd(0.05) 4.17 10.90 15.83 1.60 2.43 2.59 cv (%) 11.35 11.16 10.03 12.67 11.90 11.53 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability d0 = control (0 g duckweeds m-2), d1 = 200 g duckweeds m-2, d2 = 400 g duckweeds m-2, d3 = 600 g duckweeds m-2, n1 = 45 kg n ha-1, n2 = 90 kg n ha-1, n3 = 180 kg n ha-1 number of tillers hill-1 significant effect was found on number of tillers hill-1 of rice among the treatment at all growth stages due to application of duckweed at different rates, different doses nitrogen and its combination (table 1). results revealed that the maximum number of tillers hill-1 (9.29, 14.16 and 14.76 at 30, 60 dat and at harvest, respectively) was found from the treatment d2 which was statistically similar with d1 at 60 dat and at harvest whereas the lowest number of tillers hill-1 (6.26, 10.03 and 10.81 at 30, 60 dat and at harvest, respectively) from control treatment d0. the highest number of tillers hill-1 (7.88, 13.60 and 14.89 at 30, 60 dat and at harvest, respectively) was found from the treatment n2 which was significantly different from other treatments. the lower number of tillers hill-1 (7.39, 10.66 and 11.85 at 30, 60 dat and at harvest, respectively) was found from the treatment n3 which was statistically identical with n1. more or less similar result was also observed by karim (2019), adhikari (2018) and chamely and islam (2015) also found that n had significant effect on number of tillers hill-1. the maximum number of tillers hill-1 (11.43, 16.17 and 16.40 at 30, 60 dat and at harvest, respectively) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d1n1, d1n2, d2n1 and d3n2. the lowest number of tillers hill-1 (5.90, 9.25 and 9.80 at 30, 60 dat and at harvest, respectively) was found from the 112 hossain et al. treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1 and d3n3. number of non-effective tillers hill-1 significant effect was found on number of non-effective tillers hill-1 of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 2). the highest number of non-effective tillers hill-1 (4.25) was found from control treatment d0 which was significantly different from other treatments. the lowest number of noneffective tillers hill-1 (1.76) was found from the treatment d2. the highest number of noneffective tillers hill-1 (3.45) was found from the treatment n3while lower number of non-effective tillers hill-1 (2.26) was found from the treatment n2 followed by n1. the result obtained from the present study was followed with the findings of karim (2019) and adhikari (2018). in treatment combinations, lower number of non-effective tillers hill-1 (1.40) was found from d2n2 which was statistically similar with d1n2 and d2n1. effective tillers hill-1 number of effective tillers hill-1 of rice among the treatment was found significant due to application of duckweed at different rates, different doses nitrogen and its combination (table 2). the maximum number of effective tillers hill-1(13.02) was found from the treatment d2 followed by d1 whereas the lowest number of effective tillers hill-1 (7.41) from control treatment d0. higher number of effective tillers hill-1 (11.67) was found from the treatment n2 followed by n1 whereas the lowest number of effective tillers hill-1 (8.97) from n3. karim (2019) and chamely and islam (2015) also found significant effect of n on number of effective tillers hill-1 of rice which supported the present study. higher number of effective tillers hill-1 (14.73) was found from the treatment combination of d2n2 which was statistically similar with d1n2 whereas the lowest number of effective tillers hill-1 (6.40) was found from the treatment combination of d0n3 which was statistically similar with d0n1 and d3n3. number of grains panicle-1 number of grains panicle-1 of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination were found significant (table 2). higher number of grains panicle-1 (179.40) was foun from the treatment d2 which was statistically identical with d1 whereas the lowest number of grains panicle-1 (132.60) from control treatment d0. the maximum number of grains panicle-1 (169.70) was found from the treatment n2 which was statistically similar with n1 whereas the lowest number of grains panicle-1 (149.80) from the treatment n3. the result obtained from the present study was corroborates with the findings of karim (2019), adhikari (2018) and chamely and islam (2015). the maximum number of grains panicle-1 (189.50) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d1n1, d1n2, d2n1, d2n3 and d3n2. the lowest number of grains panicle-1 (121.50) was found from the treatment combination of d0n3 which was statistically similar with d0n1, d0n2 and d3n3. number of filled grains panicle-1 significant variation was found on number of filled grains panicle-1 of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 2). the maximum number of filled grains panicle-1 (170.00) was found from the treatment d2 which was statistically identical with d1 whereas the lowest number of filled grains panicle-1 (110.10) from control treatment d0. the highest number of filled grains panicle-1 (156.60) was found from the treatment n2 whereas the lower number of filled grains panicle-1 (129.30) from the treatment n3 which was statistically identical with n1. similar result was also observed by chamely and islam (2015) and adhikari (2018). the maximum number of filled grains panicle-1 (183.90) was found from the treatment combination of d2n2 which was statistically similar with effect of duckweed and nitrogen on growth and yield of boro rice 113 the treatment combination of d1n2, d2n1 and d2n3. lower number of filled grains panicle-1 (93.18) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1. number of unfilled grains panicle-1 statistically significant variation was found on number of unfilled grains panicle-1 of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 2). the highest number of unfilled grains panicle-1 (22.53) was found from control treatment d0.the lowest number of unfilled grains panicle-1 (9.35) was found from the treatment d2 which was significantly different from other treatments. chamely and islam (2015) also found similar result with the present study. the lowest number of unfilled grains panicle-1 (13.08) was found from the treatment n2 whereas higher number of unfilled grains panicle-1 (20.51) was found from the treatment n3 followed by n1. the lowest number of unfilled grains panicle-1 (5.62) was found from the treatment combination of d2n2 which was significantly different from other treatment combinations whereas the maximum number of unfilled grains panicle-1 (28.29) was found from the treatment combination of d0n3 followed by d0n1 and d3n3. table 2. yield contributing parameters of rice as influenced by duckweed and nitrogen and also their combination treatments yield contributing parameters no. of noneffective tillers hill-1 no. of effective tillers hill-1 no. of grains panicle-1 no. of filled grains panicle-1 no. of unfilled grains panicle-1 panicle length (cm) 1000 grain weight (g) effect of duckweed (d) d0 4.25 a 7.41 d 132.6 c 110.1 c 22.53 a 18.89 c 20.94 b d1 2.40 c 11.87 b 171.6 a 155.7 a 15.81c 23.48 a 23.05 ab d2 1.76 d 13.02 a 179.4 a 170.0 a 9.35 d 24.58 a 24.49 a d3 3.11 b 8.58 c 152.8 b 133.5 b 19.30 b 21.29 b 22.31 b lsd(0.05) 0.31 1.05 16.89 15.34 1.73 2.07 2.13 effect of nitrogen (n) n1 2.93 b 10.02 b 157.7 ab 141.1 b 16.65 b 22.01 ab 22.88 ab n2 2.26 c 11.67 a 169.7 a 156.6 a 13.08 c 23.29 a 23.82 a n3 3.45 a 8.972 c 149.8 b 129.3 b 20.51 a 20.88 b 21.40 b lsd(0.05) 0.27 0.91 14.62 13.28 1.49 1.80 1.84 combined effect of duckweed and nitrogen d0n1 4.53 a 7.57 fg 131.1 de 108.8 ef 22.26 b 18.90 ef 21.40b-d d0n2 3.43 bc 8.25 ef 145.3 c-e 128.3 de 17.03 cd 20.61 c-f 22.07a-d d0n3 4.80 a 6.40 g 121.5 e 93.18 f 28.29 a 17.17 f 19.37 d d1n1 2.47 e 11.30 cd 170.7 a-c 155.0 bc 15.69 de 23.73a-d 23.03a-d d1n2 1.53 g 13.80 ab 180.2 ab 167.4 ab 12.79 e 24.55 ab 24.45 a-c d1n3 3.20 b-d 10.52 d 163.7 a-c 144.8b-d 18.96 c 22.15b-e 21.67a-d d2n1 1.67 fg 12.80 bc 178.1 ab 168.4 ab 9.723 f 24.15 a-c 24.67 ab d2n2 1.40 g 14.73 a 189.5 a 183.9 a 5.623 g 25.83 a 25.13 a d2n3 2.20 ef 11.53 cd 170.4 a-c 157.7 a-c 12.71 e 23.75a-d 23.67 a-c d3n1 3.03 cd 8.42 ef 151.0b-d 132.1 c-e 18.94 c 21.27b-e 22.40a-d d3n2 2.67 de 9.89 de 163.7 a-c 146.8b-d 16.86 cd 22.17b-e 23.63 a-c d3n3 3.62 b 7.44 fg 143.7 c-e 121.6 de 22.09 b 20.43 d-f 20.91 cd lsd(0.05) 0.54 1.82 29.25 26.57 2.99 3.59 3.69 cv (%) 11.13 10.49 10.86 11.02 10.53 9.62 9.59 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability 114 hossain et al. d0 = control (0 g duckweeds m-2), d1 = 200 g duckweeds m-2, d2 = 400 g duckweeds m-2, d3 = 600 g duckweeds m-2, n1 = 45 kg n ha-1, n2 = 90 kg n ha-1, n3 = 180 kg n ha-1 panicle length panicle length of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination was found significant variation (table 2). the maximum panicle length (24.58 cm) was found from the treatment d2 which was statistically identical with d1 whereas the lowest panicle length (18.89 cm) from control treatment d0. the maximum panicle length (23.29 cm) was found from the treatment n2 which was statistically similar with n1 whereas the lowest panicle length (20.88 cm) from the treatment n3. the maximum panicle length (25.83 cm) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d1n1, d1n2, d2n1 and d2n3. the lowest panicle length (17.17 cm) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1, d0n2 and d3n3. weight of 1000 grain significant variation was found on 1000grain weight of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 2). the maximum 1000grain weight (24.49 g) was found from d2 which was statistically similar with d1 whereas the lowest 1000grain weight (20.94 g) was found from control treatment d0 which was statistically identical with d3. the maximum 1000grain weight (23.82 g) was found from the treatment n2 which was statistically similar with n1 whereas the lowest 1000 grain weight (21.40 g) from the treatment n3. the result obtained from the present study was following with the findings of chamely and islam (2015). the maximum 1000grain weight (25.13 g) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d0n2, d1n1, d1n2, d1n3, d2n1, d2n3, d3n1 and d3n2. the lowest 1000grain weight (19.34 g) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1 and d3n3. grain yield significant effect was found on seed yield of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 3). higher grain yield (6.24 t ha-1) was found from the treatment d2 which was statistically identical with d1 whereas the lowest grain yield (3.87 t ha-1) was found from control treatment d0. the maximum grain yield (6.08 t ha-1) was found from the treatment n2 which was followed by n1. the lowest grain yield (4.39 t ha-1) was found from the treatment n3 which was significantly different from other treatments. gewaily and adel (2018) was also found a linear increase in grain yield with continuous rate increase of nitrogen from 0 to 220 kg ha-1. the maximum grain yield (7.24 t ha-1) was found from the treatment combination of d2n2 which was statistically similar with d1n2. the lowest seed yield (3.40 t ha-1) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1, d3n1 and d3n3. the result obtained on seed yield of rice was conformity with the findings of yao and zhang (2017) that increased n use efficiency with duckweed and also found that rice cultivation using urea combined with duckweed achieved higher rice yield by 9–10%. straw yield significant effect was found on straw yield of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 3). the maximum straw yield (7.71 t ha-1) was found from the treatment d2 which was statistically effect of duckweed and nitrogen on growth and yield of boro rice 115 similar with d1 whereas the lowest straw yield (6.60 t ha-1) was found from control treatment d0. the highest straw yield (7.77 t ha-1) was found from the treatment n2 which was significantly different from other treatments. biological yield significant effect was found on biological yield of rice among the treatment due to application of duckweed at different rates, different doses nitrogen and its combination (table 3). the maximum biological yield (13.64 t ha-1) was found from the treatment d2 which was statistically identical with d1. the lowest biological yield (10.47 t ha-1) was found from control treatment d0 which was statistically identical with d3. the highest biological yield (13.84 t ha-1) was found from the treatment n2 which was significantly different from other treatments. the lowest biological yield (11.92 t ha-1) was obtained from the treatment n3 which was statistically identical with n1. chamely and islam (2015) and karim (2019) also found similar result with the present study. the maximum biological yield (15.71 t ha-1) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d1n2 and d2n1. the lowest biological yield (9.51 t ha-1) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1. table 3. yield parameters of rice as influenced by duckweed and nitrogen and their combination treatments yield parameters grain yield (t ha-1) straw yield (t ha-1) biological yield (t ha-1) harvest index (%) effect of duckweed (d) d0 3.87 c 6.60 b 10.47 b 36.90 b d1 5.89 a 7.27 ab 13.05 a 44.54 a d2 6.24 a 7.71 a 13.94 a 44.61 a d3 4.64 b 6.85 b 11.50 b 40.16 ab lsd(0.05) 0.61 0.69 1.30 4.46 effect of nitrogen (n) n1 5.01 b 6.99 b 11.92 b 41.34 n2 6.08 a 7.77 a 13.84 a 43.52 n3 4.39 c 6.57 b 10.96 b 39.80 lsd(0.05) 0.53 0.60 1.13 ns combined effect of duckweed and nitrogen d0n1 3.75 gh 6.46 cd 10.21 fg 36.76 c d0n2 4.46 efg 7.24 b-d 11.70 c-g 38.09 bc d0n3 3.40 h 6.10 d 9.51 g 35.84 c d1n1 5.84 cd 7.17 b-d 12.68 c-e 44.83 ab d1n2 6.95 ab 8.02 ab 14.97 ab 46.39 a d1n3 4.87 d-f 6.63 cd 11.51 c-g 42.41 a-c d2n1 6.16 bc 7.55 a-c 13.71 a-c 44.94 ab d2n2 7.24 a 8.47 a 15.71 a 46.09 a d2n3 5.31 c-e 7.10 b-d 12.41 c-f 42.82 a-c d3n1 4.30 e-h 6.76 cd 11.07 d-g 38.83 a-c d3n2 5.65 cd 7.34 a-c 13.00 b-d 43.52 a-c d3n3 3.98 f-h 6.45 cd 10.43 e-g 38.12 bc lsd(0.05) 1.06 1.20 2.25 7.72 cv (%) 12.09 9.93 10.87 10.98 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability d0 = control (0 g duckweeds m-2), d1 = 200 g duckweeds m-2, d2 = 400 g duckweeds m-2, d3 = 600 g duckweeds m-2, n1 = 45 kg n ha-1, n2 = 90 kg n ha-1, n3 = 180 kg n ha-1 116 hossain et al. lower straw yield (6.57 t ha-1) was found from the treatment n3 which was statistically identical with n1. the maximum straw yield (8.47 t ha-1) was found from the treatment combination of d2n2 which was statistically similar with the treatment combination of d1n2, d2n1 and d3n2. lower straw yield (6.10 t ha-1) was found from the treatment combination of d0n3 which was statistically similar with the treatment combination of d0n1, d1n3, d3n1 and d3n3. harvest index significant effect was found on harvest index of rice among the treatment due to application of duckweed and combined effect of duckweed and nitrogen, but non-significant in nitrogen application at different doses (table 3). higher harvest index (44.61%) was found from the treatment d2 which was statistically similar with d1 and d2 whereas the lowest harvest index (36.90%) from control treatment d0. the highest harvest index (43.52%) was found from the treatment n2 whereas the lowest harvest index (39.80%) from n3. karim (2019) and chamely and islam (2015) was also found similar result. the maximum harvest index (46.09%) was found from the treatment combination of d2n2 which was statistically identical with the treatment combination of d1n2. treatment combinations, d1n1 and d2n1 were similar with d2n2. the lowest harvest index (35.84%) was found from the treatment combination of d0n3 which was statistically identical with d0n1. conclusion considering the above results, it may be concluded that (400 g duckweeds m-2) application showed the superiority over other treatments to produce higher grain yield of rice. nitrogen (90 kg n ha-1) application showed higher rice yield over other nitrogen treatments. application of 400 g duckweeds m-2 with 90 kg n ha-1 performed the best among the treatments. the trial is confined in one location with one season resulr so, more research is needed in different agroecological zones (aez) of bangladesh for regional adaptability and other performances. references adhikari, j. 2018. effect of nitrogen fertilizer and weed management on the yield of transplant aman rice. j. bangladesh agril. univ. 16(1): 12–16. bali, a.s., m. siddique, b.a. ganai, h.v. khan and k.n. singh. 1995. response of rice (oryza sativa) genotypes to nitrogen levels under transplanted conditions in kashmir valley. indian j. agron. 40(1): 35-37. bbs. 2018. bangladesh bureau of statistics. statistical year book of bangladesh. stat. div. min. planning. dhaka. chamely, s.g. and n. islam. 2015. effect of variety and nitrogen rate on the yield performance of boro rice. progress. agric. 26 (1): 6-14. chen, x., z. cui, m. fan, x. yan, n. an, w. zhang, and f. zhang. 2014. producing more grain with lower environmental costs. nature. 514: 486-489. cheng, j., b. a. bergmann, j. j. classen, a.m. stomp, and j.w. howard. 2002. nutrient recovery from swine lagoon water by spirodela punctata. bioresour. technol. 81: 81-85. daniel, k.v. and k. wahab. 1994. levels and time of nitrogen in semi dry rice. madras agric. j. 81(6): 357-358. gewaily, e.e. and m.g. adel. 2018. effects of nitrogen levels on growth, yield and nitrogen use efficiency of some newly released egyptian rice genotypes. open agriculture. 3: 310–318. http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0040 effect of duckweed and nitrogen on growth and yield of boro rice 117 hussain, t., g. jilani, and a. ghaffar. 1989. influence of rate and time of nitrogen application on growth and yield of rice in pakistan. int. rice. res. newsl. 14(6): 18. karim, m. 2019. effect of different doses of urea on the yield of boro rice varieties in haor areas of bangladesh. asian pl. res. j. 3(2): 1-9. li, f., z. wang, j. dai, q. li, x. wang, c. xue, h. liu and g. he. 2015. fate of nitrogen from green manure, straw, and fertilizer applied to wheat under different summer fallow management strategies in dry land. biol. fert. soils. 51: 769-780. li, h., x. liang, y. lian, l. xu and y. chen. 2009. reduction of ammonia volatilization from urea by a floating duckweed in flooded rice fields. soil sci. soc. am. j. 73: 1890-1895. marazi, a.r., g.m. khan, k.h. singh and a.s bali. 1993. response of rice (oryza sativa) to different n levels and water regimes in kashmir valley. indian j. agric. sci. 63(11): 726 727. meena, s.l., s. surendra, y.s. shivay and s. singh. 2003. response of hybrid rice (oryza sativa) to nitrogen and potassium application in sandy clay loam soils. indian j. agric. sci. 73(1): 811. mohedano, r.a., r.h.r. costa, f.a. tavares and p. belli-filho. 2012. high nutrient removal rate from swine wastes and protein biomass production by full-scale duckweed ponds. bioresour. technol. 112: 98-104. sun, h.j., h.l. zhang, j. min, y.f. feng and w.m. shi. 2015. controlled-release fertilizer, floating duckweed, and biochar affect ammonia volatilization and nitrous oxide emission from rice paddy fields irrigated with nitrogen-rich wastewater. paddy wat. environ. 14: 105-111. yao, y. and m. zhang. 2017. duckweed (spirodela polyrhiza) as green manure for increasing yield and reducing nitrogen loss in rice production. field crops res. 214: 273–282. zhang, x., e.a. davidson, d.l. mauzerall, t.d. searchinger, p. dumas and y. shen. 2015. managing nitrogen for sustainable development. nature. 528: 51-59. zimmo, o.r., n.p. van-der-steen and h.j. gijzen. 2003. comparison of ammonia volatilisation rates in algae and duckweed-based waste stabilisation ponds treating domestic wastewater. water res. 37: 4587-4594. http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0120 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0120 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0115 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0135 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0135 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0175 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0175 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0175 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0175 http://refhub.elsevier.com/s0378-4290(17)30650-0/sbref0175 microsoft word baj 362c__press bangladesh agron. j. 2020, 23(1): 101-106 effect of weeding and herbicide management on fibre yield and yield attributes of tossa jute j. ferdous, m.s. hossain, m.a. alim and m.m. islam1 agronomy division and 1planning, training and communication division, bangladesh jute research institute, dhaka, bangladesh corresponding e-mail: tanny.jannat92@gmail.com (received: 20 february 2020, accepted: 18 august, 2020) keywords: jute yield, whip super 9 ec, sunrice ® 150wg, weeding abstract the experiment was conducted at jute agriculture experimental station (jaes), manikganj and jute research regional station, faridpur during 2019 to find out the effect of weeding and herbicide management on fibre yield and yield attributes of tossa jute (var. o-9897) cultivation. two herbicide treatments, such as; w1 = fenoxaprop-p-ethyl (whip super 9 ec) and w2 = ethoxysulfuron (sunrice ® 150wg) were tested. there were 14 treatments. t1t6 treatments did not include hand weeding which was done 20 days after the herbicide spray [t1 = 100% recommended doses (rd) of both w1and w2 where w2 was sprayed one day after that of w1, t 2 = 50% dose both of w1and w2where w2was sprayed one day after that of w1, t3 = 100% dose of both w1 and w2 where both of the herbicide mixed together and sprayed on the same day, t4 = 50% dose of both w1 and w2 where mixture of both were sprayed on the same day, t5 = only 100% dose of w1, t6 = only 100% dose of w2]. the treatments t7 t12 included one had weeding following the application of herbicides [t7 = 100% dose both of w1 and w2 where w2 was sprayed 1 day after that of w1, t8 = 50% dose both of w1 and w2 where w2 was sprayed 1 day after of w1, t9 = 100% dose both of w1 and w2 were mixed and sprayed together on the same day, t10 = 50% dose both of w1 and w2 mixed together and sprayed same day, t11 = only 100% dose of w1, t12 = only 100% dose of w2]. the treatments t13 and t14 did not include herbicide application [t13 = two hand weeding (20-25 and 45-50 das) and t14 = control with no herbicide application]. the experiment was laid out in rcbd with three replications. results revealed that khudesama (echinochloa colonum) and angulighash (digitaria sanguinalis), khudesama and mutha (cyperus rotundus) were best controlled by herbicide application. t3 gave highest fibre yield of 1.89 tha -1 when w1 and w2 sprayed at the same day with 100% rd. in case of one weeding 20 days after spray fibre yield and stick yield were differed significantly as compared to those of control at manikganj. treatment t7 gave highest fibre yield (3.11 t ha -1) when w2 sprayed after 1 day of w1 with 100% rd. at faridpur, t3 gave the highest fibre yield (2.68 t ha-1) when w1 and w2 sprayed at the same day with 100% rd. incase of one weeding 20 days after spray, t7 gave highest fiber yield (2.79 t ha -1) when w2 was sprayed 1 day after that of w1 with 100% rd. introduction jute is an upland crop grown in summer season in bangladesh. it is the most important fibre crop as well as one of the cash crops of the country. weed is one of the most important pests in 102 ferdous et al. jute which deteriorate the yield and quality of fibre to a considerable extent. weeds affect light interception and passing of wind and affect photosynthesis in jute plant and ultimately crop will receive stunted growth. in consequence, yield of crop is reduced (islam and rahman, 2008); kundu, 1958). the hot and humid environment of summer is highly favorable for weed germination and weed growth. as a result, weeding and thinning operations involve about 40% or more of the labour cost investment in jute cultivation. in bangladesh, weeds are generally controlled by raking and nirani (hand weeding). in bangladesh, weeds are generally controlled by raking and nirani (hand weeding) and weeding and thinning operations involve about 50% or more of the labour cost (alam, 2003). an effective weed management practice is necessary for higher crop production and better economic return (gaffer et al., 1988). herbicide has effectiveness in terms of weed control in jute field. different factors affect weed infestation in a field, among them water, light and mineral nutrients (talukder, 1978). therefore, a routine weedicide field trial experiment was undertaken in two different aez for jute fibre production. materials and methods the experiment was conducted at jute agriculture experimental station (jaes), jute research manikganj and jute research regional station, faridpur in 2019 to find out the effect of weeding and herbicide management on fibre yield and yield attributes of tossa jute cultivation. the experiment was laid out in rcbd with three replications. unit plot size was 4.0m x 2.5m. space between plot to plot and around the field was 1.0 m and between replications 1.5 m. tossa jute varieties o-9897 was used as the study material. two different herbicide treatments, such as; w1 = fenoxaprop-p-ethyl (whip super 9 ec); w2 = ethoxysulfuron (sunrice®150wg) were tested. there were 14 treatments. t1 t6 treatments did not include hand weeding which was done 20 days after the herbicide spray [t1 = 100% doses of both w1 and w2 where w2 was sprayed one day after that of w1, t2 = 50% dose both of w1 and w2 where w2 was sprayed one day after that of w1, t3 = 100% dose of both w1 and w2 where both of the herbicide mixed together and sprayed on the same day, t4 = 50% dose of both w1 and w2 where mixture of both were sprayed on the same day, t5 = only 100% dose of w1, t6 = only 100% dose of w2]. the treatments t7 t12 included one had weeding following the application of herbicides [t7 = 100% dose both of w1 and w2 where w2 was sprayed 1 day after that of w1, t8 = 50% dose both of w1 and w2 wherew2 was sprayed 1 day after of w1, t9 = 100% dose both of w1 and w2 were mixed and sprayed together on the same day, t10 = 50% dose both of w1 and w2 mixed together and sprayed same day, t11 = only 100% dose of w1, t12 = only 100% dose of w2]. the treatments t13 and t14 did not include herbicide application [t13= two hand weeding (20 25 and 45 50 das) and t14 = control with no herbicide application]. crops were sown on last week of march to first week of april and harvested 120 days after sowing. results and discussion manikganj results revealed that all the weedicide of different dose significantly controlled the weeds. the parameters like plant population, base diameter and plant height differed significantly due to weeding and herbicide application at manikganj (table 1). plant population and plant height both were significantly increased at different treatments with weedicide spray than control plot. fibre yield and stick yield were differed significantly with control but in case of only weedicide spray without weeding at faridpur (fig. 1). effect of weeding and herbicide management on tossa jute 103 treatment t3 (2.06 tha -1) gave maximum fibre yield when w1 and w2 sprayed at the same day with 100% rd followed by t4 (2.06 t ha -1) when w1 and w2 sprayed at the same day with 50% rd. in case of one weeding 20 days after spray, fibre yield and stick yield were differed significantly than control at manikganj (fig. 1). treatment t7 (3.11 t ha -1) gave maximum yield when w2 sprayed after 1 day of w1 with 100% rd followed by t10 (2.81 t ha -1) when mixture sprayed same day of w1 with 50% rd. the lowest result was found at control (1.44 t ha -1). the results were in agreement with sadiq et al. (2002); salkin and nagaari (1983); rafique (1980) and ross and lembi (1985). table1. effect of weeding and herbicide management on growth parameters of tossa jute at manikganj treatments pp (m-2) ph (m) bd (mm) t1 w1+w2 100% of rd w2 was sprayed 1 day after of w1 35.15 2.57 14.85 t2 w1+w2 50% of rd w2 was sprayed 1 day after of w1 34.79 2.52 13.97 t3 w1+w2 100% of rd mixture was sprayed same day of w1 36.03 2.65 15.11 t4 w1+w2 50% of rd mixture was sprayed same day of w1 33.63 2.53 14.32 t5 w1 100% of rd w1 was sprayed as per method 33.62 2.55 14.62 t6 w2 100% of rd w2 was sprayed as per method 34.43 2.35 14.74 t7 w1+w2 100% of rd w2 was sprayed 1 day after of w1 40.40 2.93 15.73 t8 w1+w2 50% of rd w2 was sprayed 1 day after of w1 36.87 2.71 14.77 t9 w1+w2 100% of rd mixture was sprayed same day of w1 39.52 2.75 14.19 t10 w1+w2 50% of rd mixture was sprayed same day of w1 36.38 2.78 15.38 t11 w1 100% of rd w1 was sprayed as per method 35.16 2.62 15.34 t12 w2 100% of rd w2 was sprayed as per method 35.04 2.48 14.59 t13 normal weed management 2 weeding (20-25 & 4550 das) 37.78 2.89 15.59 t14 control (no weeding & spraying) 28.50 2.08 11.41 lsd(0.05) 2.39 0.30 2.71 cv (%) 2.55 3.81 6.18 ns = not-significant, pp = plant population, ph = plant height, bd = base diameter, w1 = fenoxapropp-ethyl (whip super 9 ec); w2 = ethoxysulfuron (sunrice 150wg); rd = recommended dose faridpur results showed that all the weedicide of different dose significantly controlled the weeds. yields and all the yield contributing parameters like plant population, base diameter and plant height differed significantly due to weeding and herbicide management at faridpur (table 2). plant population and plant height both were significantly increased at different treatments with 104 ferdous et al. weedicides spray when compared with control plots. fibre yield and stick yield were differed significantly than in comparison to those of control but only under weedicide spray without weeding at faridpur (fig. 2). treatment t3 (2.68 t ha -1) gave the maximum fibre yield when w1 and w2 were sprayed at the same day using 100% rd which followed by t5 (2.52 t ha -1) when only w1 was sprayed using 100% rd. one weeding 20 days after spray, the fibre yield and stick yield were differed significantly compared to those of control at faridpur (fig 2). fig. 1. effect of weeding and herbicide management on fibre and stick yield of tossa jute at manikganj table 2. effect of weeding and herbicide management on growth parameters of tossa jute at faridpur treatments pp (m-2) ph (m) bd (mm) t1 w1+w2 100% of rd w2 will be sprayed 1 day after of w1 34.81 2.34 10.74 t2 w1+w2 50% of rd w2 will be sprayed 1 day after of w1 34.22 2.42 11.18 t3 w1+w2 100% of rd mixture will be sprayed same day of w1 34.79 2.63 11.85 t4 w1+w2 50% of rd mixture will be sprayed same day of w1 33.48 2.48 11.14 t5 w1 100% of rd w1 will be sprayed as per method 34.00 2.64 12.60 t6 w2 100% of rd w2 will be sprayed as per method 34.43 2.25 9.82 t7 w1+w2 100% of rd w2 will be sprayed 1 day after of w1 39.53 2.70 13.51 t8 w1+w2 50% of rd w2 will be sprayed 1 day after of w1 36.35 2.55 11.77 t9 w1+w2 100% of rd mixture will be sprayed same day of w1 36.70 2.29 10.94 t10 w1+w2 50% of rd mixture will be sprayed same day of w1 38.14 2.61 13.04 t11 w1 100% of rd w1 will be sprayed as per method 34.78 2.43 10.51 t12 w2 100% of rd w2 will be sprayed as per method 34.83 2.56 11.70 t13 normal weed management 2 weeding (20-25 & 45-50 das) 37.61 2.50 11.54 t14 control (no weeding & spraying) 28.54 2.48 10.65 lsd(0.05) 3.38 ns 2.95 cv (%) 3.19 7.01 8.53 ns = not-significant, pp = plant population, ph = plant height, bd = base diameter, w1 = fenoxapropp-ethyl (whip super 9 ec); w2 = ethoxysulfuron (sunrice 150wg); rd = recommanded dose treatment t7 gave highest yield (2.79 t ha -1) when w2 was sprayed one day after that of w1 using 100% rd. the lowest fibre yield was found with control (1.74 t ha-1) which could be due 0.00 1.00 2.00 3.00 4.00 5.00 6.00 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 y ie ld ( t h a -1 ) treatments fibre yield (t/ha) stick yield (t/ha) effect of weeding and herbicide management on tossa jute 105 to incidence of more weeds in the control plots. similar results were also reported by jamil et al. (2000); ross and lembi (1985); sadiq et al. (2002) and ahmad (1996). fig. 2. effect of weeding and herbicide management on fibre yield and stick yield of tossa jute at faridpur conclusion from the above results, it could be concluded that the fibre yield and stick yields differed significantly in comparison with those of control under weedicide spray without weeding both at manikganj and faridpur. treatment t3 gave highest fibre yield of 1.89 tha -1 when w1 and w2 were sprayed at the same day with 100% rd. in case of one weeding 20 days after spray, both the fibre yield and stick yields differed significantly compared to those of control at manikganj with t7 (3.11 t ha -1) which gave the highest yield when w2was sprayed after one day of w1using 100% rd. at faridpur t3 gave the highest fibre yield (2.68 t ha -1) when w1 and w2were sprayed at the same day using 100% rd. in case of one weeding 20 days after spray, t7 also gave the highest yield (2.79 t ha -1) when w2 was sprayed one day after that of w1 using 100% rd. references ahmad, s.s., a. abid, z.a. cheema and a. tanveer. 1996. study of various chemical weed control practice in lentil. j. agric. res. 34: 127-134. alam, a.t.m.m. 2003. present status and future strategies of weed management in jute field. jute and jute fabrics, bangladesh. newsletter of bangladesh jute res. inst. january-march.pp.46. gaffer, m.a., t.m.t. iqbal and m.s. alam.1988.weed and seed (in bengali). published by t. m. jubair bin iqbal, villagemonipotal, p.o. meghai, sirajganj. pp.221-238. islam, m.m. and m. rahman. 2008. in: hand book on agricultural technologies of jute, kenaf and mesta crops. bangladesh jute res. inst., manikmia avenue, dhaka-1207, bangladesh.p.82. 0.00 1.00 2.00 3.00 4.00 5.00 6.00 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 t14 y ie ld ( t h a -1 ) treatments fibre yield (t/ha) stick yield (t/ha) 106 ferdous et al. jamil, m., a. sattar, s.w. hassan and a.l. malghani. 2000. effect of time dose of stomp (weedicide) application on weed control in lentil under the irrigated conditions. sci. inter. 12: 305-307. kundu, b.c. 1958. in: jute in india. ministry for food and agriculture. govt. of india, new delhi. pp.100-105. rafique, i. 1980. nodulation and growth response of lentil to herbicide application. lens. 7: 54-55. ross, m.a. and c.a. lembi. 1985. applied weed science. burggs pub. co. minnesota, usa. salkin, a.b. and d. naygaari. 1983. survey of weed in lentil in northeastern syria. lens. 10: 2931. sadiq, m., m. jamil, s.m. mehdi, m. sarfraz, m.r. gondal and g. hassan. 2002. effect of various weedicide on weed control and yield of lentil crop in salt affected soil. asian j. plant sci. 3: 275-276. talukder, f.a.h. and m. waseque. 1978. weeds and their control with special reference to jute field weeds. jute jute fab. bangladesh. 2: 23-30. bangladesh agron. j. 2022, 25(1): 67-73 effect of rice husk on arsenic accumulation in potato plant under different levels of arsenic treated soil t.s. roy1, m.s. rahman2, m. mostofa3, m. nahid4, m.g. khatun5 and m.a. razzaque4 1department of agronomy, 2department of bio chemistry, 4department of agricultural chemistry, faculty of agriculture, sher-e-bangla agricultural university, bangladesh 3tuber crops research centre, bangladesh agricultural research institute, gazipur 5institute of seed technology, faculty of agriculture, sher-e-bangla agricultural university corresponding e-mail: tuhinsuvraroy@sau.edu.bd (received: 10 may 2022, accepted: 22 may 2022) keywords: arsenic, potato flesh, peel, haulm, root, rice husk abstract a pot experiment was conducted in the experimental field of sher-e-bangla agricultural university, dhaka during the period from november, 2020 to may, 2021 to find out the effect of rice husk as an bio-adsorbent to decontaminate as toxicity in potato. the experiment consisted of two factors. factor a: arsenic levels (4) viz., as0: control (0 mg as kg-1 soil), as1: 20 mg as kg-1 soil, as2: 40 mg as kg-1 soil, and as3: 60 mg as kg-1 soil. factor b: rice husk levels (4) viz., r0: control (0 g kg-1 soil), r1: 20 g kg-1 soil, r2: 40 g kg-1 soil and r3: 60 g kg-1 soil. the experiment was laid out in a factorial randomized complete block design with three replications. results revealed that as and/or rice husk had significant effect on arsenic load in different plant parts of potato t. arsenic content in potato tuber flesh, peel, haulm and root gradually increased with the increase of its levels. on the contrary, as content in plant parts decreased with increasing rice husk levels. the soil treated with as1r3 exhibited as accumulation in tuber flesh (0.1070 mg kg -1 fresh weight) and peel (0.443 mg kg -1 fw), respectively. as load in different plant parts was in the sequence: root > haulm > tuber peel > tuber flesh. although, the least as loading in tuber flesh was observed in as1r1, as1r2, as1r3 (range 0.1258-0.1070 mg kg-1 fw) which also showed higher productivity (range 402.67 416.67 g plant-1), but the treatment combination of as1r1 may be suitable for safe potato cultivation in lower level as contaminated soil. therefore, potato growers can grow potato up to 20 mg as kg-1 contaminated soil treated with 20 g rice husk kg1 soil, which contains safe as load than the critical one (0.157 mg as kg -1 fw) for human consumption. so, application of rice husk for potato cultivation may a good option to reduce the arsenic hazards in lower arsenic endemic areas. introduction arsenic (as), the toxic metalloid element, causes terrible health hazards to human beings. around 110 million people in south and south-east asia are suffering from this problem, the magnitude is considered to be the maximum in bangladesh (sanyal, 2005). as-contaminated groundwater used for irrigation may pose serious health hazard to people eating food from irrigated crops (williums et al., 2006). roychowdhury et al. (2003) reported that the contribution of food-chain towards as pollution in human is many folds greater than that of the drinking water. the acute minimal lethal dose of as in adults is estimated to be 1 mg-1kg-1day-1 (das et al., 2004). recent studies suggest that a number of crops and vegetable plant species accumulate significant amount of as. 68 roy et al. the higher as accumulation was observed in aroids, amaranth, radish, lady’s finger, cauli flower, and brinjal, whereas the lower level of as accumulation was observed in potato, beans, green chili, tomato, bitter guard, and turmeric, etc. due to the as-contaminated irrigation water (mandal and suzuki, 2002). as concentration in plants varied from less than 0.01 to about 5.0 g kg-1, whereas the food safety limits of less than 1.0 mg kg-1 (abedin et al., 2002). potato is a world’s single most important tuber crop with a vital role in the global food system and food security (brown, 2005). bangladesh was the world’s 8th largest producer of potatoes with a total production of about 97,44,412 million ton (faostat, 2019). potato consumption as processed and fresh food is also increasing considerable in bangladesh. people living in as affected areas are consuming contaminated potatoes that creates serious health problems. bio-sorption technology includes metal removal performance for industrial waste water. this process is economical and eco-friendly compare with others (lee et al., 2009). it is a conventional technique for metal remediation. bio sorption uses adsorbents derived from non-living biomass like sawdust, rice husk, egg shell etc. and removes toxic metals from industrial waste water and contaminated soil (lee et al., 2013). however, it is necessary to search for appropriate agricultural management practices to minimize the arsenic content in tubers. in this context, the present investigation was mainly axed of as accumulation in potato through rice husk application. materials and methods the pot experiment was conducted at the research field of sher-e-bangla agricultural university. the location of the site is 23.740n latitude and 90.350e longitude with an elevation of 8.2 meter from sea level. the experiment consisted of two factors. factor a: arsenic levels (4) viz., as0: control (0 mg as kg-1 soil), as1: 20 mg as kg-1 soil, as2: 40 mg as kg-1 soil, and as3: 60 mg as kg-1 soil. factor b: rice husk levels (4) viz., r0: control (0 g kg-1 soil), r1: 20 g kg-1 soil, r2:40 g kg-1 soil and r3: 60 g kg-1 soil. the two factors experiment was laid out in a randomized complete block design with five replications. rice husk was collected from a rice mill. the collected soil was sandy loam. soil ph and organic carbons were 5.8 and 0.44%, respectively. the experimental soil of basket was fertilized with a recommended dose of n, p, k, s, zn, b and cowdung @ 575 µg, 345 µg, 750 µg, 108 µg, 18 µg, 8.75 µg and 50 g, respectively, per 10 kg soil (mondal et al., 2011). the certified grade potato tubers of var. courage were used as planting material. collected seed potato tubers were kept at room temperature to facilitate sprouting. the properly sprouted, healthy, and uniform sized (60-70 g) seed potato tubers were planted according to treatment and an entire potato planted in each basket. seed potatoes were planted on an average 5-6 cm depth in the basket. all the intercultural operations and plant protection standards were taken as per tuber crops research centre recommendation. haulm (shoot of potato plant) pulling was done at 90 dap when the majority of plants showed senescence and the tops started drying. after haulm pulling, the tubers were kept under the soil for 10 days for skin hardening. the potatoes of each basket were separately harvested, bagged, tagged and brought to the laboratory for further analysis. all yield contributing parameters were calculated as per tuber crops research centre, bari, bangladesh. potatoes were harvested and packed with labeled net bags according to treatment. haulm (above ground portion), roots and tuber were collected as per treatment. after peeling the tuber, both peel and flesh samples were separated into different labeled packets. the labeled packets were immediately sent to the analytical laboratory of bangladesh council of scientific and industrial research (bcsir), dhaka, where arsenic was determined with an atomic absorption spectrophotometer (hg-aas) following usepa method 1632 (usepa, 2001). the data obtained for different characters were statistically analyzed to observe the significant difference among different treatments. the analysis of variance of all the recorded parameters performed using statistics-10 software. the difference of the means value was separated by least significant difference (lsd) at 5% level of probability (gomez and gomez, 1984). effect of rice husk on arsenic accumulation in potato 69 results and discussion arsenic accumulation in tuber flesh the arsenic load in tuber flesh increased with increasing arsenic level (table 1). a higher concentration of arsenic in soils also created higher absorption of this element by plant parts, which were damaged and restricted plants growth (onken and hossner, 1995). on the contrary, arsenic load in tuber flesh decreased with increasing the rate rice husk application (table 2). the treatment combination of different arsenic and rice husk levels significantly influenced arsenic load in tuber flesh (table 3). the least amount of arsenic load in tuber flesh was observed in as1r3 (0.1070 mg kg-1 fw), whereas, the maximum was recorded in as3r0(0.5063 mg kg-1 fw). the overall arsenic accumulation result showed that high bio adsorbent in soil that occurred more bio sorption process as a result increasing of rice husk levels in a particular concentration of arsenic. arsenic content in tuber flesh drastically decreased by only increasing of rice husk level. rice husk acted as a bioadsorbent in soil and breakdown by microorganism with the presence of soil water and produced cellulosic waste materials viz., acetamido, amido, amino, alcoholic, carbonyl, phenolic, sulphydryl groups, etc., by microorganism with the presence of soil water adsorb arsenic by rice husk from the soil solution and make an intermediate complex between soil colloid and arsenic. rice husk has a close affinity for heavy metal remediation from the aqueous solutions (sud et al., 2008). as a result, when rice husk (bio-adsorbent) levels increased in soil occurred more biosorption process, then the concentration of as decreased in tuber flesh (table 3). table 1. effect of arsenic levels on arsenic accumulation (mg kg-1 fw) in different plant parts of potato at harvest treatments tuber flesh tuber peel haulm root as0 0.0000 d 0.0000 d 0.0000 d 0.0000 d as1 0.1983 c 0.6938 c 4.2545 c 5.1320 c as2 0.2623 b 1.4469 b 5.8308 b 9.0067 b as3 0.3739 a 2.0305 a 8.2600 a 12.821 a lsd(0.05) 0.0103 0.287 0.6987 4.114 cv (%) 5.94 9.30 18.27 7.32 in a columns means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of probability. as0: control, as1: 20 mg as kg-1 soil, as2: 40 mg as kg-1 soil, as3: 60 mg as kg1 soil. arsenic accumulation in tuber peel arsenic content of tuber peel varied significantly with different arsenic levels. the arsenic content of the tuber peel gradually increased with increasing arsenic levels (table 1). the minimum arsenic load in tuber peel was recorded in as1 (0.6938 mg kg-1 fw/), while the maximum in as3 (2.0305 mg kg-1 fw/). arsenic concentration in potato peel was higher than arsenic concentration in potato flesh (norton et al., 2013). arsenic load in tuber peel varied significantly with different rice husk levels. the arsenic load in tuber peel gradually decreased with increasing rice husk levels (table 2). the lowest arsenic load in tuber peel was recorded in r3 (0.5795 mg kg-1 fw) while the maximum in r0 (1.7423 mg kg-1 fw). table 2. effect of rice husk levels on arsenic accumulation (mg kg-1 fw) in different plant parts of potato cv. courage treatments tuber flesh tuber peel haulm root r0 0.3592 a 1.7423 a 6.6577 a 9.1834 a r1 0.1982 b 1.0799 b 4.3503 b 7.0293 b 70 roy et al. r2 0.1604 c 0.7694 c 3.5818 c 5.8994 c r3 0.1167 d 0.5795 d 3.7555 bc 4.8472 d lsd(0.05) 0.103 0.287 0.6987 4.114 cv (%) 5.94 9.30 18.27 7.32 in a columns means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of probability. ns= non-significant, r0-= 0 g rice husk kg-1 soil, r1 =20 g rice husk kg-1 soil, r2= 40 g rice husk kg-1 soil, r3= 60 g rice husk kg-1 soil the treatment combination of arsenic and rice husk levels significantly influenced the arsenic load in potato peel (table 3). the maximum arsenic load in tuber peel was observed in as3r0 (3.8277 mg kg-1 fw) while no accumulation was found in as0 r0 followed by as0 r1, as0r2 and as0r3 because no arsenic was treated in soil and the minimum arsenic load was recorded in as1r3 (0.3443 mg kg-1 fw). table 3 also showed that only by increasing of rice husk level, the accumulation of arsenic decreased in tuber peel. rice husk acted as a bioadsorbent in soil and breakdown by microorganism with the presence of soil water and produced cellulosic waste materials viz., acetamido, amido, amino, alcoholic, carbonyl, phenolic, sulphydryl groups, etc. by microorganism with the presence of soil water adsorb arsenic by rice husk from the soil solution and make an intermediate complex between soil colloid and arsenic. rice husk has a close affinity for heavy metal remediation from the aqueous solutions (sud et al., 2008). high bioadsorbent in soil occurred more bisoroption process as a result increasing of rice husk levels in a particular concentration of arsenic, arsenic content in tuber peel decreased. the experimental results exhibited that arsenic concentration in potato peel was always higher than arsenic concentration in potato flesh. norton et al. (2013) also stated similar trends of arsenic load in tuber flesh and peel. arsenic accumulation in haulm arsenic accumulation in haulm (above ground shoot) varied significantly due to different arsenic levels. table 1 showed that the arsenic load in haulm progressively increased with increasing arsenic levels due to a higher concentration of arsenic in soils also creates higher absorption of this element by haulm. onken and hossner (1995) also indicated similar opinion. arsenic accumulation in haulm varied significantly with different rice husk levels (table 2). the result also demonstrated that arsenic load in haulm decreased with increasing rice husk level. the combination of arsenic and rice husk levels showed significant effect on arsenic loading by haulm (table 3). the maximum arsenic load in haulm was observed in as3r0 (13.360 mg kg-1 fw) while no accumulation was found in as0 r0 followed by as0 r1, as0r2 and as0r3 because no arsenic was treated in soil and the minimum arsenic load was recorded in as1r2 (3.0477 mg kg-1 fw). arsenic accumulation in root accumulation of arsenic in root differed significantly due to different levels of arsenic were treated in soil (table 1). the amount of arsenic load in root progressively increased with increasing arsenic levels. on the contrary, the accumulation of arsenic gradually decreased with increasing rice husk levels (table 2). the combined effect of arsenic and rice husk was also significant on arsenic loading by root. table 9 showed that the maximum arsenic load in root was detected in as3r0 (17.950 mg kg-1 fw) while no accumulation was found in as0 r0 followed by as0 r1, as0r2 and as0r3 because no arsenic was treated in soil and the minimum arsenic load was recorded in as1r3 (3.4497 mg kg-1 fw). table 3. combined effect of arsenic and rice husk on arsenic accumulation (mg kg-1 fw) in different plant parts of potato at harvest treatment combinations tuber flesh tuber peel haulm root as0 r0 0.0000 h 0.0000 k 0.0000 g 0.0000 j as0 r1 0.0000 h 0.0000 k 0.0000 g 0.0000 j effect of rice husk on arsenic accumulation in potato 71 as0r2 0.0000 h 0.0000 k 0.0000 g 0.0000 j as0r3 0.0000 h 0.0000 k 0.0000 g 0.0000 j as1r0 0.4407 c 1.0807 g 5.5943 cd 7.4513 f as1r1 0.1258 g 0.8343 h 3.8697 ef 5.2343 g as1r2 0.1223 g 0.5157 i 3.0477 f 4.3927 h as1r3 0.1070 g 0.3443 j 4.5063 de 3.4497 i as2r0 0.4900 a 2.0610 b 7.6760 b 11.332 c as2r1 0.2070 e 1.6227 d 5.7973 cd 9.2470 d as2r2 0.1923 e 1.2183 f 5.1173 cde 8.1340 ef as2r3 0.1600 f 0.8857 h 4.7327 de 7.3133 f as3r0 0.5063 a 3.8277 a 13.360 a 17.950 a as3r1 0.4627 b 1.8627 c 7.7343 b 13.636 b as3r2 0.3270 d 1.3437 e 6.1623 c 11.071 c as3r3 0.1997 e 1.0880 g 5.7830 cd 8.6260 de lsd(0.05) 0.0207 0.573 1.3973 8.228 cv (%) 3.95 9.30 18.27 7.32 in a colums means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of probability. ns= non-significant, as0: control, as1: 20 mg as kg-1 soil, as2: 40 mg as kg-1 soil, as3: 60 mg as kg-1 soil. r0= 0 g rice husk kg-1 soil, r1= 20 g rice husk kg-1 soil, r2 =40 g rice husk kg-1 soil, r3 = 60 g rice husk kg-1 soil accumulation pattern of arsenic in potato plant parts the maximum accumulation of arsenic was detected in the root (53.6%) as compared to those of other plant parts (figure 1). the roots contained a higher arsenic load than haulm> tuber peel > tuber flesh. haulm accumulated 43.6% arsenic, whereas, tuber only 3.8%. finally, tuber flesh (1.5%) accumulated arsenic very low concentration of this toxic metalloid as compared to all other plant parts. comparison of arsenic loading of different plant parts clearly showed that translocation of arsenic in edible part is relatively lower than the any other plant parts. generally, the distribution arsenic load in plant parts is found to be in the order: root> haulm>tuber. abedin et al. (2002) and sanyal (2005) also observed similar order for arsenic loading in potato plant parts. a plant can only uptake arsenic as as (iii) and as (v). however, it is possible when arsenic complex hydrolysis in soil solution and make as (iii) and as (v) but when bioadsorbent like rice husk was present in the soil the as (iii) and as (v) made a bond with different cellulosic organic complex with soil colloid and produced intermediate complex among arsenic, cellulosic compound and soil colloid. in this regard, the plant could not accumulate arsenic. rice husk has a close affinity for heavy metal remediation from the aqueous solutions (sud et al., 2008). the sorption of heavy metals towards biomaterials is attributed to their constituents, which are mostly carbohydrates, proteins, and phenolic compounds because they carry functional groups, for example, amines, carboxyls, and hydroxyls, which can bind to the metal ions (choi and yun, 2006). 72 roy et al. fig. 1. arsenic accumulation pattern of potato (average value of all treatments). conclusion rice husk had significant effect on arsenic accumulation in plant parts of potato. the soil treated with 60 g rice husk kg-1 soil, decreased 67.51 and 66.73% arsenic accumulation through tuber flesh and peel, respectively compared to without rice husk. among the treatment combinations, although as1r1, as1r2 and as1r3 were found suitable but as1r1 was the appropriate because, in this combination, tuber flesh accumulated only 0.1233 mg as kg-1 fw which is still lesser than the critical level of arsenic contamination (0.15 mg kg-1 fw), so, potato growers can cultivate potato up to 20 mg kg-1 arsenic contaminated soil using 20 g rice husk kg-1 soil. since arsenic content in tuber reduced with increasing the rice husk levels, so further onfarm research trial at arsenic contaminated areas is to be done to find out another bio-adsorbents to minimize more than 80% of arsenic load from potato tuber. acknowledgement this study was supported by sher-e-bangla agricultural university research system (saures). references abedin, m.j., j. feldmann and a.a. meharg. 2002. uptake kinetics of arsenic species in rice plants. plant physiol. 128: 1120-1128. https://doi.org/10.1104/pp.010733. brown, c.r. 2005. antioxidants in potato. amer. j. potato res. 82:163-172. choi, s. and y. yun. 2006. biosorption of cadmium by various types of dried sludge: an equilibrium study and investigation of mechanisms. j. hazard mater 138: 378-383. https://doi.org/10.1016/j.jhazmat.2006.05.059. das, h.k., a.k. mitra, p.k. sengupta, a. hossain, f. islam and g.h. rabbani. 2004. arsenic concentrations in rice, vegetables, and fish in bangladesh: a preliminary study. environ. intl. 30: 383-387. 43.6 % 53.6 % 1.5 % 2.3 % haulm root tuber flesh tuber peel https://doi.org/10.1104/pp.010733 effect of rice husk on arsenic accumulation in potato 73 faostat (fao, statistics division). 2019. statistical database. food and agricultural organization of the united nations, rome, italy. gomez, k.a and a.a. gomez. 1984. statistical procedure for agricultural research. wiley inter-science publication, new york. p.680. lee, h.y., c. jeon, k.j. lim, k.c. hong, j.e. lim, b.s. choi, n.w. kim, j.e. yang and y.s. ok. 2009. adsorption characteristics of heavy metal ions onto chemically modified rice husk and sawdust from aqueous solutions. korean j. environ. agric. 28: 158-164. https://doi.org/10.5338/kjea.2009.28.2.158. mondal, m.r.i., m.s. islam, m.a.b. jalil, m.m. rahman, m.s. alam and m.h.h. rahman. 2011. krishi projukti hatboi (handbook of agro-technology), 5th edition. bangladesh agricultural research institute, gazipur-1701, bangladesh. p.307. norton, g., c. deacon, a. mestrot, j. feldmann, p. jenkins, c. baskaran and a.a. meharg. 2013. arsenic speciation and localization in horticultural produce grown in a historically impacted mining region. environ. sci. technol. 47: 6164-6172. https://doi.org/10.1021/es400720r. onken, b.m. and l.r. hossner. 1995. plant uptake and determination of arsenic species in soil solution under flooded conditions. j. environ. qual. 24: 373–381. https://doi.org/10.2134/jeq1995.00472425002400020022x. roychowdhury, t., t. uchino, h. tokunaga and m. ando. 2002. survey of arsenic in composites from an arsenic affected areas of west bengal, india. food chem. taxicol, 40: 1611-21. sanyal, s. k. 2005. arsenic contamination in agriculture: a threat to water-soil-crop-animal-human condition 92nd session of indian science congress association. ahamadabad, india, 3-7 january, 2005. saud, d., g. mahajan and m. kaur. 2008. agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions –a review. bioresour. technol, 99: 6017-6027. https://doi.org/10.1016/j.biortech.2007.11.064. usepa (us environmental protection agency). 2001. method 1632, revision a: chemical speciation of arsenic in water and tissue by hydride generation quartz . willium, p.n., m.r. islam, e.e. adomako, a. raab, s.a. hossain and y.g. zhu. 2006. increase in rice grain arsenic for regions of bangladesh irrigating paddies with elevated arsenic in ground waters. environ. sci. technol. 40: 4903-08. https://doi.org/10.2134/jeq1995.00472425002400020022x bangladesh agron. j. 2021, 24(1): 93-100 inluence of different levels of cowdung on mitigation of water deficit effect on wheat a.k.m.r. amin1 and s. reza2 1professor and 2ms student, department of agronomy, sher-e-bangla agricultural university corresponding e-mail: ruhulsau@yahoo.com (received: 10 april 2021, accepted: 20 april 2021) keywords: organic manure, water deficit, growth stages, yield, wheat abstract the experiment was conducted in pot at the net house of the department of agronomy, sher-e-bangla agricultural university, dhaka during the period from november, 2018 to march, 2019to find out the optimum dose(s) cowdung to mitigate the water deficit effect on wheat. the experiment comprised of two factors viz. factor a: five levels of cowdung, i) c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose, and factor b: four levels of water deficit at, i) d0 = control (no water deficit), d1= crown root initiation stage (20-19 das), d2 = booting stage (45-54 das) and d3= an thesis stage (55-64 das). the experiment was laid out in a factorial r and omized complete block design with three replications. the test crop variety was bari gom28. the result reveled that cowdung level had positive impact on yield of wheat under water deficit condition, and 50% higher cowdung of recommended dose (c4) gave the highest grain yield (5.12g plant-1). the particular treatment also produced the highest number of effective tillers plant-1 (5.25), spike length (10.39 cm), spikelet spike-1 (15.72), grains spike-1 (32.56), grains spikelet-1 (2.07) and 1000-grain weight (47.32 g) of wheat. the treatment c3 (25% higher cowdung of recommended dose) also gave statistically similar yield with c4 treatment. in respect of water deficit imposition treatments, grain yield was found the highest in control treatment which was statistically similar with water deficit imposition at booting stage treatment (d2). these two treatments also showed the higher and similar number of effective tillers plant-1 (4.86 and 4.58), spike length (10.53cm and 10.11cm), spikelets spike-1(15.50 and 15.19), grains spike-1 (34.10 and 30.17), grains spikelet-1 (2.20 and 1.98) and 1000-grain weight (45.42g and 45.36g, respectively). regarding the interaction of levels of cowdung and water deficit imposition at different stages of plant growth, c4d0 and c3d0 were highest yielder which was attributed to higher 1000-seed weight, number of effective tillers plant-1, spikelets spike-1 and grains spike-1. contrary, 25% higher cowdung than recommended dose (as it saved 25% cowdung) seems promising to overcome yield loss due to water deficit imposition at booting stage of wheat (d2). however, application of cowdung (12.5 t ha-1) was found effective to combat water deficit at booting stage (d2) of wheat compared to other growth stages. introduction wheat production of bangladesh was 11.0 lac metric tons and area cover 3.5 lac hectares (bbs, 2019). drought affects all plant development stages from germination, vegetative and mailto:ruhulsau@yahoo.com 94 amin et al. reproductive growth to grain filling and maturation of the crop (hossain et al., 2012). drought reduces nitrogen (n) uptake efficiency and utilization by plants. drought is one of the major abiotic stresses that affect at least 60% of wheat production in high-income countries and about 32% of 99 million hectares in least developed countries (chen et al., 2012). water deficit might decrease wheat grain yield from 17 to 70% (nouri-ganbalani et al., 2009). daryanto et al. (2016) reported 20.6% yield losses in 40% reduced water. sarwar (2005) found that grain yield and yield components of wheat significantly increased with the application of different organic materials resulting in the compost to be the most superior one. in addition, yassen et al. (2006) found that the irrigation at 60% water holding capacity and applying mineral 60kg nfed-1, with presence of the chicken manure as an organic fertilizer produced the highest wheat yield. on the other hand, amin and baque (2020) observed that application of organic manure could reduce the impact of drought on wheat irrespective of growth stages. they also observed that application of cowdung (10 t ha-1) was found more effective to combat drought impact at booting stage of wheat. as such, this research work was designed to determine the effect of different levels of cowdung on mitigation of water deficit effect on wheat. materials and methods apot experiment was conducted at the net house of the department of agronomy, sher-ebangla agricultural university (sau), dhaka-1207, during the period of november 2018 to march 2019. the experimental field was located at 24o09՛ n latitude and 90026՛ e longitude at a height of 8.5 m above the sea level (fao/undp, 1988). the soil of the experimental site was clay loam belonging to the “madhupur tract” under aez 28. two factors experiment werefactor a: five levels of cowdung, viz.i) c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose, and factor b: four levels of water deficit at, i) d0 = control (no water deficit), d1= crown root initiation stage (2019 das), d2 = booting stage (45-54 das) and d3= anthesis stage (55-64 das) (amin and baque, 2020). the experiment was laid out in a factorial r and omized complete block design with three replications. the test crop variety of wheat was bari gom28. sixty earthen pots measuring 22 cm diameter and 18 cm height was fill-up with 20 kg of soil. urea, tsp, mop, gypsum, zincoxide and boric acid were used at the rate of 200, 72, 66, 110, 4 and 5 kg ha-1, respectively (brri, 2006 / frg, 2018), which were 2.00, 0.72, 0.66, 1.10, 0.04 and 0.05 g pot-1, respectively and mixed all of them except urea with the soil before fill-up the pot. urea was applied in three equal installments at pot filling, 21 das and 55 das. recommended dose of cowdung was 10 t ha-1 and was applied as per treatment. seeds of wheat variety bari gom28 were collected from bangladesh agriculture research institute (bari), joydebpur, gazipur. before sowing, seeds were treated with provex 200ec @ 2.5 g powder for kg-1 seed. fifteen seeds were sown in each pot on 21st november 2018. after sowing, the seeds were covered with soil and lightly pressed by hand. for assessment, five plants were kept in each pot after 14 das. different intercultural operations were done to ensure normal growth and development of the crop except irrigation. irrigation was applied as per need of treatment of the experiment where irrigation was not applied during water deficit imposition period(s) treatments. on the basis of physiological maturity, the crop was harvested from 4-10 march, 2019. data on different crop characters, yield attributes and yield were collected from the harvested five plants from each pot. post-harvest operations likethreshing, cleaning and drying of grains were done separately for each treatment. properly dried grain and straw were weighed and converted into g plant-1 basis. the collected data of each pot were statistically analyzed by using the computerinluence of cowdung on water deficit mitigation of wheat 95 based software statistics 10. mean difference among the treatments were compared with duncan’s multiple range test (dmrt) test at 5 % level of significance. results and discussion the result reveled that different cowdung treatment varied significantly with respect to yield and yield contributing characters of wheat (table 1 and table 2). the yield advantages of 0.78, 0.48, 0.38 and 0.13g plant-1 for c4 (50% higher cowdung of recommended dose) applied pot over c0 (no cowdung), c1 (25% less cowdung of recommended dose), c2 (recommended dose of cowdung) and c3 (25% higher cowdung of recommended dose, respectively) applied pot was found possibly due to maximum effective tillers plant-1 (5.25), spike length (10.39cm), spikelets spike-1 (15.72), grains spike-1 (32.56), grains spikelet-1 (2.07), weight of 1000grains (47.32 g), straw yield (6.47 g plant-1), biological yield (11.39 g plant-1) and harvest index (44.08%) in the c4 applied treatment. on the other hand, c3 treatment gave statistically similar yield and yield attributes with c4 treatment in some traits. the result agreed with the findings of amin and baque (2020), hammad et al. (2011) and ibrahim et al. (2008) that organic manure increased wheat yield over control. according to uyanoz et al. (2006) yield attributes of wheat improve with organic manure which corroborates with the present results. table 1. effect of different levels of cowdung on plant characters and yield attributes of wheat cowdung dose plant height (cm) effective tillers plant-1 (no.) spike length (cm) spikelets spike-1 (no.) grains spike-1 (no.) grains spikelet-1 (no.) weight of 1000 grains (g) c0 66.65 c 2.94 e 9.48 c 14.07 b 22.36 d 1.58 c 39.51 c c1 68.07 bc 3.56 d 9.68 bc 14.25 b 26.25 c 1.84 b 41.86 b c2 68.08 bc 3.90 c 9.82 bc 14.48 b 28.78 b 1.99 ab 42.85 b c3 69.97 ab 4.68 b 10.17 ab 15.50 a 31.36 a 2.02 ab 46.58 a c4 72.14 a 5.25 a 10.39 a 15.72 a 32.56 a 2.07 a 47.32 a se 1.33 0.13 0.27 0.34 0.71 0.08 1.00 cv (%) 4.71 8.07 6.78 5.58 6.18 10.87 5.62 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance by dmrt. here: c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose table 2. effect of different levels of cowdung on yield and harvest index of wheat cowdung dose grain yield plant-1 (g) straw yield plant-1 (g) biological yield plant-1 (g) harvest index (%) c0 4.34 d 5.90 b 10.24 b 42.29 c1 4.64 c 6.08 ab 10.72 b 43.21 c2 4.76 bc 6.17 ab 10.79 b 43.47 c3 4.99 ab 6.50 a 11.48 a 43.37 c4 5.12 a 6.47 a 11.59 a 44.08 se 0.126 0.247 0.294 ns cv (%) 6.45 9.72 6.56 5.84 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significanc by dmrt. here: c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose, and ns = not significant https://www.researchgate.net/profile/hafiz_hammad?_sg=fkqgoy4kb07hvrr6lm72m-jt7kfl9k7nar0uwaaorlryfsi3xhh_q_rrc-jcst7qcvhhjdg.g9fje5swm_xby25cxphaxcmx68dasscsifzsnw3cumrxx2fcf1qhhkjlta8fdelgfvvdqva0lmv9sqfyiebiqw 96 amin et al. significant difference existed among the water deficit-imposed treatments, the control plants d0 and d2 showed maximum statistically similar grain yield, spike length, spikelets spike-1, weight of 1000 grains and harvest index (table 3 and table 4). without drought treatment was superior by producing 34.41 and 19.78% higher yield over d3 and d1 treatments, respectively. on the other hand, d2 treatment was out yielded by producing 29.18 and 15.11% higher yield over d3 and d1, respectively. the treatment without drought also produced highest level of tillers plant-1, spikelets spike-1, grains spike-1, straw yield, biological yield and harvest index than drought imposition plants. however, among the drought imposition treatments, d2gave highest yield and yield attributes than other drought imposition treatments. the present result was confirmatory with the findings of amin and baque (2020) and akram (2011) that drought imposition at different growth stages caused severe reduction in yield and yield components of wheat. similar result was also observed by alghabari and isham (2018) that drought stress affected barley yield through impaired grain development and grain filling duration. table 3. effect of water deficit treatment on plant characters and yield attributes of wheat water deficit stage plant height (cm) effective tillers plant-1 spike length (cm) spikelets spike-1 grains spike-1 grains spikelet-1 weight of 1000 grains (g) d 0 73.41 a 4.86 a 10.53 a 15.50 a 34.10 a 2.20 a 45.42 a d1 70.75 b 3.94 c 9.69 bc 14.75 b 26.08 c 1.76 c 42.87 b d 2 67.31 c 4.58 b 10.11 ab 15.19ab 30.17 b 1.98 b 45.36 a d 3 64.46 d 2.88 d 9.29 c 13.84 c 22.70 d 1.62 c 40.84 c se 1.19 0.12 0.24 0.30 0.64 0.07 0.89 cv (%) 4.71 8.07 6.78 5.58 6.18 10.87 5.62 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance here: d0 = control (no water deficit), d1= water deficit at crown root initiation stage (20-19 das), d2 = water deficit atbooting stage (45-54 das) and d3= water deficit at anthesis stage (55-64 das) table 4. effect of water deficit treatment on yield and harvest index of wheat water deficit stage grain yield plant-1 (g) straw yield plant-1 (g) biological yield plant-1 (g) harvest index (%) d0 5.39 a 6.72 a 12.11 a 44.47 a d1 4.50 b 6.01 b 10.51 b 42.82 ab d 2 5.18 a 6.63 a 11.70 a 43.84 ab d 3 4.01 c 5.53 c 9.54 c 41.99 b se 0.11 0.23 0.26 0.92 cv (%) 6.45 9.72 6.56 5.84 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. d0 = control (no water deficit), d1= water deficit at crown root initiation stage (20-19 das), d2 = water deficit atbooting stage (45-54 das) and d3= water deficit at anthesis stage (55-64 das). inluence of cowdung on water deficit mitigation of wheat 97 interaction of cowdung level and water deficit imposition treatments showed significant variation in all the studied parameters (table 5 and table 6). the interaction of c4d0 and c3d0 performed best in respect of grain yield (5.93 and 5.62 g plant-1, respectively) which may be attributed to highest effective tillers plant-1, spike length, spikelets spike1, grains spikelet1 and weight of 1000grains in these interactions. on the other hand, interaction of c3d2 also showed statistically similar yield (5.48 g ha-1) and yield contributing characters with c4d0 and c3d0 interactions. table 5. interaction effects of different levels of cowdung and water deficit imposition treatment on plant characters and yield attributes of wheat interaction plant height (cm) effective tillers plant-1 spike length (cm) spikelets spike-1 grains spike-1 grains spikelet-1 weight of 1000grain (g) c0d0 71.67 a-d 3.81 fg 10.26 a-g 14.71 c-h 26.99 f-h 1.83 e-h 42.63 ef c0d1 68.67 c-g 2.22 k 9.16 g-i 13.73 g-i 21.18 j 1.54 h-i 38.04 g c0d2 64.85 gh 3.43 gh 9.47 c-i 14.42 d-i 24.55 hi 1.70 gh 40.35 fg c0d3 61.40 h 2.31 jk 9.01 i 13.42 hi 16.72 k 1.25 i 37.03 g c1d0 73.38 a-d 4.08 d-f 10.47 a-d 15.01 a-g 32.70 cd 2.18 a-d 45.19 c-e c1d1 70.91 a-f 3.77 fg 9.30 e-i 14.23 f-i 23.51 ij 1.65 gh 40.15 fg c1d2 65.92 f-h 3.88 fg 9.83 b-i 14.63 c-h 27.50 fg 1.88 d-g 44.05 d-f c1d3 62.08 h 2.52 i-j 9.10 hi 13.11 i0 21.30 j 1.62 gh 38.04 g c2d0 72.27 a-d 4.58 d 10.16 a-h 15.24 a-f 35.62 b 2.34 ab 37.97 g c2d1 69.38 b-g 4.02 ef 9.64 c-i 14.37 e-i 26.49 f-h 1.84 e-h 43.75 d-f c2d2 66.11 e-h 4.16 d-f 10.03 b-i 14.86 b-g 30.52 de 2.05 b-f 45.75 b-e c2d3 64.54 gh 2.83 ij 9.43 d-i 13.45 hi 22.50 ij 1.67 gh 43.94 d-f c3d0 74.33 ab 5.67 a-c 10.57 a-c 16.22 ab 36.07 b 2.22 a-c 49.63 ab c3d1 71.12 a-f 4.45 de 10.06 b-i 15.66 a-c 30.54 de 1.95 c-g 45.44 c-e c3d2 68.23 d-g 5.53 bc 10.40 a-e 15.9 a-c 33.78 bc 2.12 a-e 48.41 a-c c3d3 66.21 e-h 3.06 hi 9.63 c-i 14.50 d-h 25.06 g-i 1.73 f-h 42.82 ef c4d0 75.42 a 6.16 a 11.20 a 16.33 a 39.13 a 2.40 a 51.67 a c4d1 73.68 a-c 5.25 c 10.30 a-f 15.76 a-d 28.70 ef 1.82 e-h 46.99b-d c4d2 71.42 a-e 5.91 ab 10.80 ab 16.10 ab 34.48 bc 2.14 a-e 48.22 a-c c4d3 68.05 d-g 3.66 fg 9.27 f-i 14.70 c-h 27.93 e-g 1.90 e-h 42.38 ef se 2.65 0.27 0.55 0.67 1.43 0.17 2.00 cv (%) 4.71 8.07 6.78 5.58 6.18 10.87 5.62 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance by dmrt. here: c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose; d0 = control (no water deficit), d1= water deficit at crown root initiation stage (20-19 das), d2 = water deficit atbooting stage (45-54 das) and d3= water deficit at anthesis stage (55-64 das). 98 amin et al. table 6. interaction effects of different levels of cowdung and water deficit imposition treatment on yield and harvest index of wheat interaction grain yield plant-1 (g) straw yield plant-1 (g) biological yield plant-1 (g) harvest index (%) c0d0 4.82 d-g 6.36 a-e 11.18 c-f 43.11 ab c0d1 4.13 h-j 5.70 d-f 9.83 g-i 42.01 ab c0d2 4.91 d-f 6.44 a-d 11.35 c-f 43.26 ab c0d3 3.51 k 5.10 f 8.61 j 40.77 b c1d0 5.13 b-d 6.48 a-d 11.61 b-e 44.19 ab c1d1 4.50 f-i 5.97 b-f 10.47 e-h 42.98 ab c1d2 5.07 c-e 6.45 a-d 11.52 b-e 44.00 ab c1d3 3.86 jk 5.40 ef 9.26 ij 41.67 b c2d0 5.45 a-c 6.76 a-c 12.21 a-c 44.64 ab c2d1 4.41 f-i 5.88 c-f 10.29 f-i 42.86 ab c2d2 5.12 b-e 6.47 a-d 11.59 b-e 44.18 ab c2d3 4.07 ij 5.58 d-f 9.65 h-j 42.18 ab c3d0 5.62 ab 7.08 a 12.70 ab 44.25 ab c3d1 4.62 e-h 6.10 a-e 10.72 e-h 43.10 ab c3d2 5.48 a-c 7.06 a 12.54 ab 43.70 ab c3d3 4.23 h-j 5.74 d-f 9.97 g-i 42.43 ab c4d0 5.93 a 6.91 ab 12.84 a 46.18 a c4d1 4.86 d-g 6.40 a-d 11.26 c-f 43.16 ab c4d2 5.32 b-d 6.75 a-c 12.07 a-d 44.08 ab c4d3 4.37 g-i 5.82 c-f 10.19 f-i 42.89 ab se 0.25 0.49 0.59 2.06 cv (%) 6.45 9.72 6.56 5.84 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s)differ significantly at 5% level of significance by dmrt. here: c0= control (no cowdung), c1= 25% less cowdung of recommended dose, c2 = recommended dose of cowdung, c3 = 25% higher cowdung of recommended dose and c4 = 50% higher cowdung of recommended dose; d0 = control (no water deficit), d1= water deficit at crown root initiation stage (20-19 das), d2 = water deficit atbooting stage (45-54 das) and d3= water deficit at anthesis stage (55-64 das). conclusion it isconcluded from the result that although both of 50% and 25% higher cowdung than recommended dose gave the highest yield but 25% higher cowdung than recommended dose (as it save 25% cowdung) may be suggested to overcome yield loss due to water deficit conditionat booting stage of wheat (d2). acknowledgement the author acknowledged the sher-e-bangla agricultural university research system (saures) for providing financial support to conduct the study at sher-e-bangla agricultural university campus. inluence of cowdung on water deficit mitigation of wheat 99 references akram, m. 2011. growth and yield components of wheat under water stress of different growth stages. bangladesh j. agril. res. 36(3): 455-468. alghabari, f. and m.z. ishan. 2018. effect of drought stress on growth, grain filling duration, yield and quality attributes of barley (houdium vilgare l.). bangladesh j. bot.47(3): 421-428. amin, a.k.m.r. and m.a. baque. 2020. influence of organic manures on drought stress at different growth stages of wheat. bangladesh agron. j. 23(2): 81-86. bbs (bangladesh bureau of statistics). 2019. year book of agricultural statistic-2018. statistics and informatics div., ministry of planning. govt. people's repub., bangladesh, dhaka. bari (bangladesh agricultural research institute). 2020. gom utpadon projukti (in bangla). krishi projukti hatboi (part 1), 4th edition. pp.13-14. chen, x., d. min, t.a.yasir and y.g. hu. 2012. field crops research evaluation of 14 morphological, yield-related and physiological traits as indicators of drought tolerance in chinese winter bread wheat revealed by analysis of the membership function value of drought tolerance (mfvd). field crop res. 137: 195–201. daryanto, s., l. wang, p.a. jacinthe, l. cordain, a. simopoulos, d. ray, n.mueller, p. west, j. foley and n. kadam. 2016. global synthesis of drought effects on maize and wheat production. hui d, editor. plos one. 11: 0156362. https://doi.org/10.1371/journal.pone.0156362 fao/undp (food and agriculture organization). 1988.land resources appraisal of bangladesh for agricultural development report 2: agroecological regions of bangladesh. fao/undp. fao (food and agriculture organization). 2014.flood irrigation of wheat on the transitional redbrown earth. i. effect of duration of ponding on soil water, plant growth, yield and n uptake. australian j. argil. res. 42(7): 1023-1035. geravandi, m., e. farshadfar and d. kahrizi. 2011. evaluation of some physiological traits as indicators of drought tolerance in bread wheat genotypes. russian j. plant physiol. 58: 69– 75. hammad, h.m.,a. khaliq, a. ahmad and k. laghar. 2011. influence of different organic manures on wheat productivity. intl. j. agric. biol. 13(1):137-140. hossain, a., j.a. teixeira da silva, m.v. lozovskaya and v.p. zvolinsky. 2012. high temperature combined with drought affect rainfed spring wheat and barley in south-eastern russia: i. phenology and growth. saudi j. biol. sci. 19: 473-487. ibrahim,m., a. hussain, m. iqbal and e. valeem. 2008. response of wheat growth and yield to various levels of compost and organic manure. pakistan j. bot. 40(5): 2135-2141. kilic, h. and y. tacettin. 2010. the effect of drought stress on grain yield, yield components and some quality traits of durum wheat (triticumturgidum sp. durum). not. bot. hort. agrobot. cluj-napoca. 38: 164–170. liu, y., h. liang, x. lv, d. liu, x. wen and y. liao. 2016. effect of polyamines on the grain filling of wheat under drought stress. plant physiol. biochem. 100: 113-129. nezhadahmadi, a., z.h. prodhan and g. faruq. 2013. drought tolerance in wheat (review article). the sci. world j. 2013(1): 1-12. nouri-ganbalani, a., g. nouri-ganbalani, and d. hassanpanah. 2009. effects of drought stress condition on the yield and yield components of advanced wheat genotypes in ardabil, iran. j. food agric. environ. 77: 228–234. sarwar, g. 2005. use of compost for crop production in pakistan. ökologie und umweltsicherung. 26/2005. universität kassel. https://doi.org/10.1371/journal.pone.0156362 https://www.researchgate.net/profile/hafiz_hammad?_sg=fkqgoy4kb07hvrr6lm72m-jt7kfl9k7nar0uwaaorlryfsi3xhh_q_rrc-jcst7qcvhhjdg.g9fje5swm_xby25cxphaxcmx68dasscsifzsnw3cumrxx2fcf1qhhkjlta8fdelgfvvdqva0lmv9sqfyiebiqw 100 amin et al. uyanoz, r., u. cetin and e. karaarslan. 2006. effect of organic materials on yields and nutrient accumulation of wheat. j. plant nut. 29(5): 959-974. waraich, e.a., r. ahmad and m.y. ashraf. 2011. role of mineral nutrition in alleviation of drought stress in plants. australian j. crop sci. 5: 764–777. waraich, e.a., r. ahmad, s. saifullah ahmad and a. ahmad. 2010. impact of water and nutrient management on the nutritional quality of wheat. j. plant nutr. 33: 640–653. yassen, a.a., m. abd el-hady and s.m. zaghloul. 2006. replacement part of mineral n fertilizer by organic ones and its effect on wheat plant under water regime conditions.world j. agric. sci. 2: 421-428. bangladesh agron. j. 2025, 28(1): 17-22 intercropping compatibility of cheena and kaon with groundnut at charland condition of bangladesh m. r. karim1*, j. a. chowdhury1, s. s. kakon1, m. z. ali1, m. a. h. khan1, m. a. k. mian1 and j. rahman2 1agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh 2bangladesh agricultural research institute, rars, jamalpur, bangladesh *corresponding author, email: mrkarimsau09@gmail.com (received: 07 october 2025, accepted: 20 november 2025) keywords: arachis hypogaea, bcr, charland, chenna, groundnut, intercropping, koan abstract intercropping is a sustainable cropping strategy that enhances productivity, resource-use efficiency, and economic returns, particularly in fragile agro-ecological zones such as charlands in bangladesh. this study evaluated the intercropping compatibility of groundnut (arachis hypogaea l.) with two minor cereals—cheena (panicum miliaceum l.) and kaon (setaria italica l.)—under varying row arrangements in charland ecosystems during the 2024–25 cropping season. the treatments included four intercropping systems: groundnut:cheena (4:1 and 4:2), groundnut:kaon (4:1 and 4:2), and three sole cropping systems: groundnut, cheena, and kaon. agronomic yield attributes, groundnut equivalent yield (gey), economic returns, land equivalent ratio (ler), competitive ratio (cr), and relative crowding coefficient (rcc) were analyzed. sole groundnut produced the highest pod yield (2.18 t ha−1), while intercropping reduced individual groundnut yield. however, overall system productivity improved under intercropping, with groundnut:cheena (4:2) producing the highest gey (3.20 t ha−1), gross return (tk 256,200 ha−1), gross margin (tk 201,100 ha−1), and benefit–cost ratio (4.65). groundnut:kaon (4:2) also performed strongly with a gey of 3.14 t ha−1 and a benefit–cost ratio of 4.62. all intercropping treatments recorded ler > 1.0, indicating yield advantage over sole cropping. competitive indices revealed that kaon was more aggressive than cheena, but cheena-based systems were more complementary and profitable. the findings suggest that intercropping groundnut with cheena (particularly at a 4:2 row proportion) is the most compatible and profitable option for charland conditions, ensuring enhanced productivity, profitability, and sustainability. introduction bangladesh’s agriculture is undergoing immense pressure due to the increasing population, decreasing arable land, and climate variability. among the vulnerable agro-ecosystems, charlands—riverine floodplains created by silt deposition—present both challenges and opportunities for crop production. these lands are highly fertile but fragile, characterized by sandyloam soils, recurrent flooding, poor water retention, and limited input use (paul et al., 2017). despite their vast coverage, charlands are underutilized and often associated with low-input, subsistence-level farming systems. sustainable crop intensification strategies are required to fully harness their potential. intercropping, the simultaneous cultivation of two or more crops on the same land, has been widely advocated as a viable approach to improve productivity, optimize resource utilization, and enhance resilience in marginal environments (lithourgidis et al., 2011; maitra et al., 2021). legume–cereal intercropping, in particular, has been shown to improve soil fertility through 18 karim et al. biological nitrogen fixation, increase system yield through complementary resource use, and reduce production risks through crop diversification. groundnut (arachis hypogaea l.) is one of the most important legume oilseed crops in bangladesh. it thrives in sandy and sandy-loam soils, making it well suited for charlands. groundnut provides edible oil, protein, fodder, and income for rural households (hossain et al., 2019). it is a short-duration crop, allowing flexibility in multiple cropping systems. in parallel, minor cereals such as cheena (panicum miliaceum l.) and kaon (setaria italica l.) are hardy, drought-tolerant, and adapted to marginal soils. they are nutrient-rich, containing high levels of protein, dietary fiber, vitamins, and minerals, making them valuable for food and nutrition security. despite their resilience and nutritional potential, these cereals remain underutilized in bangladesh. intercropping groundnut with cheena or kaon could provide multiple benefits: like it can enhanced productivity through better utilization of light, water, and nutrients; economic gains through higher system profitability driven by favorable market prices (tk 100 kg−1 for cheena/kaon vs tk 80 kg−1 for groundnut) and resilience through diversification and reduced yield variability. although groundnut–cereal intercropping has been widely studied (e.g., groundnut with maize, sorghum, or millet) (semahegn, 2022; sherif et al., 2005), there is limited evidence on groundnut intercropping with cheena and kaon, especially under charland conditions in bangladesh. given the government’s priority on crop diversification and nutritional security, exploring the compatibility of groundnut with minor cereals is timely. considering the above issues, the proposed study is undertaken to observe the compatibility of cheena and kaon intercropping with groundnut. materials and methods the experiment was conducted at naovanga char, jamalpur district, during rabi 202425. the experiment was laid out in rcbd design with seven treatments i.e. t1 (groundnut:cheena = 4:1), t2 (groundnut:cheena = 4:2), t3 (groundnut:kaon = 4:1), t4 (groundnut:kaon = 4:2), t5 (sole groundnut), t6 (sole cheena) and t7 (sole kaon). bari cheenabadam-9, bari cheena-1 (tushar) and bari kaon-2 were respectively taken as groundnut, cheena and kaon verieties. the plot size was 3.0 m × 3.0 m. in case of 4:1 ratios, seeds are sown with 25 cm row to row distance. in 4:2 ratios, seeds are sown with 20 cm row to row distance. groundnut was sown in line with 15 cm plant to plant spacing. cheena and kaon were sown in continous line. the plants were fertilized with 15–80–60–60–1.8 kg ha−1 of n-p-k-s-b respectively. half n and all of other fertilizers were applied during final land preparation. rest half n was applied at 40-45 das. irrigation was done as and when necessary. data on grain yield (kg ha−1), tillers per plant, panicles per plant and 1000-grain weight were collected for cereals while seeds per pod, pods per plant, number of primary branches per plant, 100-seed weight and shelling percentage were collected for groundnut. crops were harvested as whole plot basis. mean comparison among the treatments was made by lsd test at 5% level of significance. groundnut equivalent yield (gey): groundnut equivalent yield was calculated as; gey = yig + (yia × pa)/pg where, yig= yield of intercrop groundnut, pg= price of groundnut, pa= price of other intercrop component “a” and yia= yield of intercrop “a” financial analysis: to determine the most profitable groundnut-minor cereal intercropping pattern, economic analysis was done through; gross margin (tk/ha) = gross returns (tk/ha) − cost of cultivation (tk/ha) benefit cost ratio (bcr) = gross return (tk/ha) total cost of cultivation (tk/ha) land equivalent ratio (ler): to determine land use efficiency lers were calculated thus: ler = la + lb = ya / sa + yb / sb intercropping compatibility of cheena and kaon with groundnut at charland condition 19 where la and lb = partial lers of crop a (sorghum) and b (groundnut) ya and yb = individual crop yields in intercropping, sa and sb = individual crop yields in sole crop and intercrop. competitive indices: two measures of competitiveness of crops in intercropping, namely, competitive ratio (cr) and the relative crowding coefficient (rcc) were calculated as follows: (i) competitive ratio, cr cra = {(yia/ysa)/(yib/ysb)} x (zb / za) crb = {(yib/ysb)/(yia/ysa)} x (za / zb) where, cra = competitive ratio of crop ‘a’; crb = competitive ratio of crop ‘b’; yia = yield of intercrop crop ‘a’; ysa = yield of sole crop ‘a’; yib = yield of intercrop crop ‘b’; ysb = yield of sole crop ‘b’; za = proportion of crop ‘a’ in intercrop; zb = proportion of crop ‘b’ in intercrop (ii) relative crowding coefficient, rcc rcca = {(yia × zb)/(ysa – yia)} × za rccb = {(yib × za)/(ysb – yib)} × zb where, rcca = relative crowding coefficient of crop ‘a’; rccb = relative crowding coefficient of crop ‘b’; yia = yield of intercrop crop ‘a’; ysa = yield of sole crop ‘a’; yib = yield of intercrop crop ‘b’; ysb = yield of sole crop ‘b’; za = proportion of crop ‘a’ in intercrop; zb = proportion of crop ‘b’ in intercrop results and discussion yield components and yield of groundnut yield components of groundnut varied significantly under different intercropping systems. plant height, number of branches per plant, pod number, effective pod number, nut weight per square meter, and pod yield (t ha−1) were influenced by the presence of intercrops (cheena and kaon) and their row proportions (table 1). table 1. yield components and yield of groundnut in different combination here, t1= (groundnut:cheena = 4:1), t2= (groundnut:cheena = 4:2), t3= (groundnut:kaon = 4:1), t4= (groundnut:kaon = 4:2), t5= (sole groundnut) plant height ranged from 41.67 cm (t4: groundnut:kaon = 4:2) to 67.33 cm (t5: sole groundnut). the tallest plants were recorded in the sole groundnut plot, while the shortest occurred when groundnut was intercropped with kaon in a 4:2 row proportion. this suggests that interspecific competition with kaon strongly restricted groundnut vegetative growth compared to cheena. earlier studies confirm that cereals, due to their rapid early growth and higher nutrient uptake capacity, often compete more strongly with legumes for resources, leading to reduced plant height and biomass in legumes (lithourgidis et al., 2011; maitra et al., 2021). treatments plant height (cm) no. of branches plant−1 pod per plant (nos) effective pod plant −1 nut weight (g m−2) yield (t ha−1) t1 56.33 3.67 30 29 180 1.80 t2 48.33 3.33 34 31 202 1.79 t3 65.00 5.67 26 25 196 1.66 t4 41.67 5.00 29 27 205 1.98 t5 67.33 4.33 35 31 214 2.18 lsd(0.01) 9.33 1.77 3.24 3.09 20.67 0.20 cv 5.90 14.21 5.58 5.75 5.51 5.51 20 karim et al. branch number per plant was highest in groundnut:kaon (4:1) with 5.67, followed by groundnut:kaon (4:2) with 5.00. in contrast, sole groundnut produced only 4.33 branches. this may be attributed to stress-induced branching when intercropped with cereals, especially kaon, as legumes tend to compensate for competition by increasing branch numbers. pods per plant ranged from 26 (t3: groundnut:kaon = 4:1) to 35 (t5: sole groundnut). sole groundnut produced significantly higher pod numbers compared to all intercrops. similarly, effective pods per plant were highest in t5 (31 pods) and lowest in t3 (25 pods). this indicates that intercropping reduces reproductive success due to competition for assimilates. the decline was sharper under groundnut–kaon intercropping than groundnut–cheena. nut weight per square meter followed a similar pattern, being highest in sole groundnut (214 g m−2) and lowest in groundnut:cheena (4:1) (180 g m−2). however, groundnut:kaon (4:2) produced nut weight (205 g m−2) comparable to sole groundnut, indicating that although kaon reduced per plant productivity, its influence was less detrimental at the plot level under certain row ratios. pod yield per hectare was maximum in sole groundnut (2.18 t ha−1), followed by groundnut:kaon (4:2) (1.98 t ha−1). the lowest yield was observed in groundnut:kaon (4:1) (1.66 t ha−1). intercropping reduced groundnut yield in all cases, consistent with earlier reports that intercropping usually decreases the yield of the main crop compared to monoculture, but enhances overall system productivity (lithourgidis et al., 2011). thus, the results suggest that while sole groundnut ensures maximum pod yield, intercropping with kaon (4:2) provides a competitive alternative by maintaining a relatively high yield compared to other intercrops. groundnut equivalent yield and productivity advantages groundnut equivalent yield (gey) provides a holistic measure of productivity by converting intercrop yields into groundnut equivalents based on market prices (table 2). table 2. yield and groundnut equivalent yield (gey) of crops in different intercrop combination and monocrop here, t1= (groundnut:cheena = 4:1), t2= (groundnut:cheena = 4:2), t3= (groundnut:kaon = 4:1), t4= (groundnut:kaon = 4:2), t5= (sole groundnut), *market price: groundnuttk 80 kg−1, cheenatk 100 kg−1, kaontk 100 kg−1 the highest gey was recorded in groundnut:cheena (4:2) (3.20 t ha−1), followed by groundnut:kaon (4:2) (3.14 t ha−1). sole groundnut produced a gey of only 2.18 t ha−1, while sole cheena and sole kaon gave the lowest values (1.50 t ha−1 and 1.44 t ha−1, respectively). this clearly demonstrates the productivity advantage of intercropping. the higher gey in groundnut:cheena (4:2) was due to substantial cheena yield (1.13 t ha−1) along with stable groundnut performance. cheena’s shorter duration and rapid growth allow efficient use of available resources, particularly in the early growth phase, without completely suppressing groundnut. on the other hand, kaon produced comparatively lower additional yield, which explains why its contribution to gey was less than cheena. treatments yield (t ha−1) groundnut equivalent yield gey (t ha−1) groundnut cheena kaon t1 1.8 0.75 0 2.74 t2 1.79 1.13 0 3.20 t3 1.66 0 0.61 2.42 t4 1.98 0 0.93 3.14 t5 2.18 0 0 2.18 t6 0 1.2 0 1.50 t7 0 0 1.15 1.44 intercropping compatibility of cheena and kaon with groundnut at charland condition 21 these findings align with studies from india and africa where legumes intercropped with short-duration cereals improved overall system productivity and ensured greater returns compared to monocropping (maitra et al., 2021). financial analysis of cropping systems profitability is a critical determinant for farmers when choosing cropping systems. the economic analysis (table 3) revealed substantial differences among treatments. the highest gross return was obtained from groundnut:cheena (4:2) (tk 256,200 ha−1), followed closely by groundnut:kaon (4:2) (tk 251,400 ha−1). sole groundnut generated only tk 174,400 ha−1. in terms of gross margin, groundnut:cheena (4:2) (tk 201,100 ha−1) was again superior, followed by groundnut:kaon (4:2) (tk 197,000 ha−1). the lowest margin was found in sole kaon (tk 81,000 ha−1). the benefit–cost ratio (bcr) was also highest in groundnut:cheena (4:2) (4.65), indicating the most profitable system. this was followed by groundnut:kaon (4:2) (4.62). sole groundnut achieved a bcr of only 3.35. the superior profitability of intercrops, particularly with cheena, can be attributed to higher gey and favorable price structure. cheena and kaon both fetched tk 100 kg−1 in the market, compared to tk 80 kg−1 for groundnut. hence, their inclusion significantly enhanced economic returns. similar economic advantages of cereal–legume intercropping have been documented in sub-saharan africa and south asia (lithourgidis et al., 2011). table 3. financial analysis from different cropping system treatments gey gross return total cost gross margin bcr t1 2.74 219000 54600 164400 4.01 t2 3.20 256200 55100 201100 4.65 t3 2.42 193800 54200 139600 3.58 t4 3.14 251400 54400 197000 4.62 t5 2.18 174400 52000 122400 3.35 t6 1.50 120000 35000 85000 3.43 t7 1.44 115000 34000 81000 3.38 here, t1= (groundnut:cheena = 4:1), t2= (groundnut:cheena = 4:2), t3= (groundnut:kaon = 4:1), t4= (groundnut:kaon = 4:2), t5= (sole groundnut), t6= (sole cheena), t7= (sole kaon), * market price: groundnuttk 80 kg−1, cheenatk 100 kg−1, kaontk 100 kg−1 land equivalent ratio ler is a standard index for assessing the efficiency of intercropping compared to monocropping. all intercropping treatments recorded ler > 1.0 (table 4), confirming yield advantages of intercropping. groundnut:cheena (4:2) achieved the highest ler (1.76), followed by groundnut:kaon (4:2) (1.72). groundnut:cheena (4:1) and groundnut:kaon (4:1) recorded lower ler values (1.45 and 1.29, respectively). this indicates that two rows of cereals intercropped with four rows of groundnut were more resource-efficient than one row of cereals with groundnut. the additional cereal rows improved system yield without proportionately reducing groundnut yield, thereby increasing total land productivity. ler values from previous studies on legume–cereal systems ranged between 1.2–1.8, consistent with the present findings (maitra et al., 2021). competitive ratio and relative crowding coefficient the competitive ratio provides insights into the dominance of one crop over another in an intercrop system. in groundnut:cheena (4:2), cheena recorded a cr of 2.14, much higher than groundnut (1.57), indicating cheena’s competitive dominance. in groundnut:kaon (4:2), kaon had a cr of 4.62, showing even greater dominance over groundnut (cr = 1.22) (table 4). 22 karim et al. this explains why groundnut yields were more suppressed in kaon intercrops compared to cheena intercrops. kaon is more competitive in resource use, particularly for light and soil nutrients.rcc values further validate these interactions. groundnut:cheena (4:2) recorded an rcc of 7.53, indicating strong complementarity, whereas groundnut:kaon (4:1) had the lowest rcc (0.30), signifying poor compatibility.the results clearly show that, sole groundnut yields highest per crop but is less profitable than intercropping. groundnut:cheena (4:2) ensures the most profitable and resource-efficient system, balancing yield, economics, and competition. groundnut:kaon (4:2) also performs strongly and may be suitable where kaon is culturally or nutritionally preferred. intercropping enhances land productivity (ler > 1), system profitability, and risk minimization, making it highly suitable for resource-poor charland farmers. these outcomes align with the broader literature emphasizing the ecological and economic sustainability of cereal–legume intercropping (lithourgidis et al., 2011; maitra et al., 2021). table 4. land equivalent ratio (ler), competitive ratio (cr) and relative crowding coefficient (rcc) as influenced by intercropping minor cereals with groundnut treatments ler cr rcc groundnut cereal groundnut cereal t1 1.45 0.55 1.82 1.25 0.44 t2 1.76 0.64 1.57 2.14 7.53 t3 1.29 0.60 1.67 0.85 0.30 t4 1.72 0.82 1.22 4.62 1.97 here, t1= (groundnut:cheena = 4:1), t2= (groundnut:cheena = 4:2), t3= (groundnut:kaon = 4:1), t4= (groundnut:kaon = 4:2) conclusion the study confirms that intercropping groundnut with minor cereals, cheena and kaon, significantly improves productivity and profitability compared to monocropping under charland conditions. while sole groundnut yielded the highest pod output, intercropping maximized system efficiency and economic returns. the groundnut:cheena (4:2) system proved most compatible, achieving the highest gey (3.20 t ha−1), gross margin (tk 201,100 ha−1), and bcr (4.65). groundnut:kaon (4:2) was also highly productive and profitable. all intercropping systems recorded ler > 1, confirming yield advantages. therefore, adoption of groundnut:cheena (4:2) intercropping can be recommended as a profitable, resource-efficient, and sustainable cropping system for charland farmers in bangladesh. references hossain, m.i., m.m. rahman, and s. sultana. 2019. groundnut production in bangladesh: constraints and opportunities. bangladesh j. agric. res. 44(1): 1-15. lithourgidis, a.s., c.a. dordas, c.a. damalas, and d.n. vlachostergios. 2011. annual intercrops: an alternative pathway for sustainable agriculture. aust. j. crop sci. 5(4): 396-410. maitra, s., a. hossain, m. brestic, m. skalicky, p. ondrisik, h. gitari, k. brahmachari, t. shankar, p. bhadra, j.b. palai, j. jena, u. bhattacharya, s.k. duvvada, s. lalichetti and m. sairam. 2021. intercropping—a low input agricultural strategy for food and environmental security. agron. 11(2): 343. paul, s. k., m.h. rashid, and m. a. hossain. 2017. agricultural adaptation practices in charlands of bangladesh. environ. nat. resour. j. 15(1): 1-12. semahegn, z. 2022. intercropping of cereal with legume crops. int. j. res. agron. 5(1): 26-31. sherif, s.a., a.a. zohry and t. sahar. 2005. intercropped with groundnut on growth, yield and yield components of both crops. arab. univ. j. agric. sci. 13(3): 771-791. bangladesh agron. j. 2020, 23(2): 51-58 growth assessment of tropical sugarbeet as influenced by spacing m.a.t. sohel*, m.a.e. hossain, h.p. roy, s.m. reza, f.h. shanta and m.r.r. razib bangladesh sugarcrop research institute, ishurdi, pabna. corresponding e-mail: atsohel@yahoo.com (received: 22 october, 2020, accepted: 10 november, 2020) keywords: germination, growth, spacing, sugarbeet abstract the experiment was carried out at the research field of agronomy and farming systems division, bangladesh sugarcrop research institute (bsri), ishurdi, pabna during 20122013 to determine the most suitable spacing for sugarbeet cultivation in bangladesh. the experiment was conducted with nine spacing viz. 50 cm  20 cm, 60 cm  20 cm, 70 cm  20 cm, 50 cm  25 cm, 60 cm  25 cm, 70 cm  25 cm, 50 cm  30 cm, 60 cm  30 cm and 70 cm  30 cm in a randomized complete block design with three replications. the effects of spacing on sugarbeet plantation were observed on growth and growth contributing components (germination percentage, number of leaves plant -1 , root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, shoot dry weight, crop growth rate) of sugarbeet. the highest germination percentage (95.67%), number of leaves plant -1 (34.33) at 30 das, shoot length (54.07 cm) at 120 das, root fresh weight (969.47 g plant -1 ) at 150 das, shoot fresh weight (752.47 g plant -1 ) at 120 das and other growth contributing parameters were obtained with the spacing 70 cm  30 cm. however, the maximum root length (38.97 cm) was obtained with 50 cm  20 cm spacing. it was concluded that the wider spacing promoted the growth of individual beet, though the optimum spacing for maximum root growth of sugarbeet was 50 cm  20 cm. introduction sugar is an important source of energy with glucose being the most important for the body. the brain requires around 130 g of sugar (glucose) per day to keep functioning. food and agriculture organization (fao) recommend to consume for a healthy man about 13 kg sugar per year, in a sense sugar is a part of our food habit (patil and patil, 2011). there are different types of sugar producing crops in the world like sugarcane, sugarbeet, date palm, palmyra palm, stevia etc. sugarbeet (beta vulgaris) is one of the most important crops in a temperate climates (sohrabi and heidari, 2008; abdelmotagally and attia, 2009). it ranks the second as sugar crop after sugarcane in the world. sugarbeet is grown nearly in 40 countries and accounts for up to 40 to 45% of the total world sugar production (shahl et al., 2000). sugarbeet has an average sugar content of 14-20% and optimal beet yield 80 to 100 t ha -1 for the tropical climates whereas 15% sugar and 40 to 60 t ha -1 beet yield for temperate climates (syngenta, 2004). one hundred gram sugarbeet contains 42.68 kilocalories, 8 g carbohydrates, and 2g of fiber and 1 g of protein (song et al., 2010). sugarbeet is mainly a temperate crop, but for tropical region such as india, pakistan, bangladesh etc. the international company syngenta developed and introduced some new sugarbeet genotypes that can be grown successfully under tropical climatic conditions which is known as “tropical sugarbeet”. the optimum spacing in sugarbeet is very important to achieve high beet yields with good quality. sugarbeet leaves development during the growing season results in more efficient use of sunlight, since it is important for the formation and expansion of canopy (sarmadnia and koocheki, 1997). there is a mailto:atsohel@yahoo.com 52 sohel et al. close relationship between yield and production of leaf area. yield is affected by the amount of radiation received by the leaves (fortune et al., 1999; sarmadnia and koocheki, 1997). it is well known that optimum plant population density is prerequisite for high yield and quality of beets. kashem (2014) reported from a study conducted at gazipur that the best time for sowing of sugarbeet is early november with a spacing of 50cm  20cm. however, more experiments are necessary to conduct in different environment to make a conclusion on determining the optimum plant spacing for maximum productivity of sugarbeet in bangladesh. the present study was therefore, undertaken at bsri to find out the optimum plant spacing for sugarbeet cultivation in bangladesh. materials and methods the experiment was carried out at agronomy and farming systems research field, bangladesh sugarcrop research institute during november 2012 to may 2013. the experimental field was located at 24  08 n latitude and 89  04 e longitude at an average altitude is 20 m. the experiment comprised nine spacing viz. 50 cm  20 cm, 60 cm  20 cm, 70 cm  20 cm, 50 cm  25 cm, 60 cm  20 cm, 70 cm  25 cm, 50 cm  30 cm, 60 cm  30 cm and 70 cm  30 cm with three replications in a randomized complete block design. the sugarbeet variety cauvery was used in this experiment. the size of the unit plot was 16 m 2 (4 m  4 m). the experimental lands was ploughed well by tractor where the deep ploughing and cross ploughing were done four times followed by leveling with a ladder. the land was then uniformly fertilized with 120 kg n, 45 kg p, 135 kg k, 19 kg s, 2.5 kg zn and 1.2 kg b ha -1 (bsri, 2011). three weedings were done at 30, 50 and 70 das. plants were thinned at the age of 35 days after sowing to obtain one plant hill -1 . earthing-up was done to cover the root base and to facilitate drainage operation. construction and re-construction were performed during each time of weeding. the experimental field required 3 irrigations applied at 45, 90 and 125 das. data collection for growth contributing components (germination percentage, number of leaves plant -1 , root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, shoot dry weight, crop growth rate) were done from five randomly selected plants of each plot. root and shoot dry weight were measured through air-dry, and then oven dry at 70 0 c till constant weight obtained which were converted to g plant -1 . all data were statistically analyzed according to the technique of analysis of variance (anova) by means of “statistix-10” computer software package for windows version (statistix-10, 2013) and least significant difference (lsd) method was used to test the differences between treatment means at 5% level of probability. results and discussion germination percentage germination percentage did not show any significant response among different spacing of tropical sugarbeet (table 1). the maximun germination percentage (95.67%) was obtained from the spacing 70 cm  30 cm and the minimum (93.67%) was obtained from the spacing 70 cm  25 cm. table 1. germination percentage of sugarbeet as affected by spacing at 15 days after seed sowing treatments germination percentage (%) t1 = 50 cm x 20 cm 94.33 t2 = 60 cm x 20 cm 94.67 t3 = 70 cm x 20 cm 95.00 t4 = 50 cm x 25 cm 94.67 t5 = 60 cm x 25 cm 94.67 t6 = 70 cm x 25 cm 93.67 t7 = 50 cm x 30 cm 94.67 t8 = 60 cm x 30 cm 95.67 t9 = 70 cm x 30 cm 95.67 growth assessment of tropical sugarbeet as influenced by spacing 53 lsd(0.05) ns cv (%) 2.28 ns = not significant number of leaves plant -1 number of leaves plant -1 in tropical sugarbeet at different das was significantly influenced by spacing except at 30 das (fig. 1). leaf number increased rapidly up to 120 das and then decline at 150 das due to drying of older leaves with all the spacing. the highest number of leaves plant -1 (34.33) was obtained from the spacing of 70 cm  30 cm which was statistically similar with 60 cm  30 cm (33.67), 50 cm  30 cm (33.40), 70 cm  25 cm (33.33), 60 cm  25 cm (33.07) and 50 cm  25 cm (31.53) spacing at 120 das. the lowest number of leaves plant -1 (27.87) was obtained from 50 cm  20 cm which was statistically similar with 60 cm  20 cm (29.13) and 70 cm  20 cm (31.47) spacing. number of leaves plant -1 decreased in closer spacing might be due to competition for space, nutrients, light and moisture than that of wider spacing. theurer (1979) also reported that spacing affects sugar production. fig. 1 number of leaves plant -1 of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) root and shoot length a significant effect of spacing was observed at different das for root and shoot length. root length increased gradually up to 150 das (fig. 2) and shoot length increased rapidly up to 120 das but decreased at 150 das with all the spacing (fig. 3). the spacing 50 cm  20 cm created the maximum root length (38.97 cm) followed by the spacing of 60 cm x 20cm (38.04 cm), 70 cm  20 cm (37.74 cm) and minimum root length (33.17 cm) was obtained from the spacing of 70 cm  30 cm followed by the spacing 60 cm  30 cm (33.82 cm) and 50 cm  30 cm (34.21 cm) at 150 das. at 120 das, the highest shoot length (54.07 cm) was found in the spacing 70 cm  30 cm followed by the spacing 60 cm  30 cm (53.23 cm) and 50 cm  30 cm (52.17 cm) while the spacing of 50 cm  20 cm gave the lowest (44.77 cm) shoot length followed by the spacing 60 cm  20 cm (47.20 cm). the general trend was a decrease in root length with the increase of wider spacing and increase in shoot length with the increase of wider spacing throughout the growth period. pospisil et al. (2000) also reported that increasing plant population might be due to closer spacing resulted in leaf surface reduction in each plant. 54 sohel et al. fig. 2 root length plant -1 of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) fig. 3 shoot length plant -1 of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) root and shoot fresh weight root and shoot fresh weight plant -1 were significantly influenced by spacing throughout the growth period. the root fresh weight gradually increased from 30 to 150 das (fig. 4) while the shoot fresh weight gradually increased from 30 to 120 das and thereafter, slightly decreased at 150 das with all spacing (fig. 5). the highest root and shoot fresh weight (969.47 g plant -1 and 752.47 g plant -1 ) were obtained from 70 cm  30 cm spacing while the lowest weight (691.53 g plant -1 and 478.20 g plant -1 ) were accompanied with 50 cm  20 cm spacing, respectively. this might be due to the lowest number of leaves, lower root and shoot weight and results reveal that closer spacing decreases the crop growth throughout the growth period. these results were similar to el-sarag (2009), who reported that the maximum root and shoot fresh weight were achieved from the lowest plant population or wider spacing (46,000 plants fed -1 ). growth assessment of tropical sugarbeet as influenced by spacing 55 fig. 4 root fresh weight as of sugarbeet affected by spacing over the growth period (vertical bar indicates lsd at 0.05) fig. 5 shoot fresh weight of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) these findings also agreed with sadre (2012), who mentioned that the increase in beet yield characters value can be explained through the fact that, the higher biomass in treatments having comparatively less plant population was possibly due to optimum utilization of soil and other environmental resources with lower competition by the crop. heitholt and sassenrath (2010) stated that plant populations affect most root parameters of sugarbeet even under optimal growth conditions and therefore it is considered a major factor determining the degree of competition between plants. similar findings were also reported by ahmad et al. (2010) and hamidia et al. (2010). root and shoot dry weight root and shoot dry weight plant -1 were significantly influenced by spacing over the growth period. root dry weight increased gradually up to 150 das (fig. 6) and shoot dry weight increased gradually up to 120 das but, decreasing at 150 das (fig. 7) for all the spacing. the highest root and shoot dry weight (116.07 g plant -1 and 68.42 g plant -1 ) was found with 70 cm  30 cm spacing while 50 cm  20 cm spacing gave the lowest root and shoot dry weight (102.33 g plant -1 and 43.33 g plant -1 ), respectively. it happened due to inadequate number of plants in wider spacing and over population in 56 sohel et al. closer spacing. it reveals that wider spacing is the best in terms of the highest root and shoots dry weight plant -1 production. fig. 6 root dry weight of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) fig. 7 shoot dry weight of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) crop growth rate (cgr) crop growth rate of tropical sugarbeet was significantly influenced by spacing at 30–60, 60–90 and 90120 das but insignificant variation observed at 120-150 das (fig. 8). at 90-120 das, the highest cgr (2.56 g day -1 ) was achieved from 70 cm  25 cm spacing which was statistically similar with all other spacing due to efficient utilization of environmental factors like light, air, soil nutrient, soil moisture etc. because of its optimum canopy development. spacing of 50 cm  20 cm caused by narrow spacing lowered the cgr (1.99 g day -1 ) due to competition among over populated plants. growth assessment of tropical sugarbeet as influenced by spacing 57 fig. 8 crop growth rate of sugarbeet as affected by spacing over the growth period (vertical bar indicates lsd at 0.05) conclusion the findings of the study reflected that despite the individual plant with wider spacing of 70 cm  30 cm produced the maximum growth of sugarbeet the spacing 50 cm  20 cm was the optimum for higher root yield. references abdel-motagally, f.m.f. and k.k. attia. 2009. response of sugarbeet plants to nitrogen and potassium fertilization in sandy calcareous soil. int. j. agric. bio. 11: 695-700. ahmad, z.p., k.m. shah, h. el-sharkawi, p.b.s. gama, e.a. khan, t. honna and s. yamamoto. 2010. sugarbeet (beta vulgaris l.) response to different planting methods and row geometries ii: effect on plant growth and quality. j. food agric. envir. 8(2): 785-791. bsri. 2011. sugarbeet cultivation in bangladesh. bangladesh sugarcrop research institute. ishurdi, pabna, bangladesh. p.4. el-sarag, e.i. 2009. maximizing sugarbeet yield, quality and water use efficiency using some agriculture practice under north sinai conditions. suez canal university, egypt. bull. fac. agric. cairo univ. 60: 2-13. fortune, r.a., j.i. burke, t. kennedy and e. o’sullivan. 1999. effect of early sowing on the growth, yield and quality of sugarbeet. j. field crops res. 19: 3-17. hamidia, a., n. khodabandehb and a.d. mohammadynasabc. 2010. plant density and nitrogen effects on some traits of maize (zea mays l.). plant ecophys. 2: 47-52. heitholt, j.j. and g.f. sassenrath. 2010. inter-plant competition: growth responses to plant density and row spacing physiology of cotton. pp.179-186. kashem, m.n. 2014. effect of sowing date, spacing, nitrogen and potassium on growth, yield and quality of tropical sugarbeet. ph. d. thesis, fac. agron., bsmrau univ., gazipur, bangladesh. patil, a.s. and k.a. patil. 2011. production consumption and deficit of sugar at global level in 2010-11 and 2011-12 a forecast www.ibap. pospisil, m., a. pospisil and m. rastija. 2000. effect of plant density and nitrogen rates upon the leaf area of seed sugarbeet on seed yield and quality. euro. j. agron. 12: 69-78. http://www.ibap/ 58 sohel et al. sadre, p. a. soleymani and h.r. javanmard. 2012. root yield and quality traits of sugarbeet (beta vulgaris l.) in relation to nitrogen fertilizer and plant density in isfahan region. int. j. agric. crop sci. 4(20): 1504-1507. sarmadnia, g.h. and a. koocheki. 1997. crops physiology. publications of mashhad university jahad, iran. shahl, i.h., n.u. khanl, g. flasool and n. saeed. 2000. effect of sowing time and plant population on root yield and accumulation of sugar in sugarbeet. pak. j. bio. sci. 3(12): 2005-2007. sohrabi, y. and g. heidari. 2008. influence of withholding irrigation and harvest times on yield and quality of sugarbeet (beta vulgaris). intl. j. agric. biol. 10: 427-431. song, w., c.m. derito and m.k. liu. 2010. cellular antioxidant activity of common vegetables. j. agric. food chem. 58(11): 6621-6629. statistix 10. 2013. analytical software. tallahassee, florida, usa. syngenta. 2004. syngenta bangladesh ltd. http// sugarbeet.ucdavis.edu/ sbpm/nutrients/ fig1. gif. www.sugarproducer.com, 2011. sugar producer magazine. theurer, j.c. 1979. growth patterns in sugarbeet production. j. americ. soc. sugarbeet tech. 20(4): 343367. bangladesh agron. j. 2022, 25(1): 37-45 phenotyping rice germplasm associated with salinity tolerance under hydroponics system a. biswas1*, s. akter1, s. mondal1,2*, h.n. barman1, s. pervin1, m.m.e. ahmed1, m.s. rahman1 and r. yasmeen1 1bangladesh rice research institute, gazipur-1701, bangladesh 2bangabandhu sheikh mujibur rahman agricultural university, gazipur-1706, bangladesh *corresponding e-mail: satyen1981@gmail.com; avijitbrri@gmail.com.com (received: 13 march 2022, accepted: 26 may 2022) keywords: genetic variation, germplasm, phenomics, rice, salinity abstract screening of different rice (oryza sativa l.) germplasms or breeding lines is a continuous effort to identify the promising source. a series of experiments (20) were undertaken to identify promising materials for five years of salinity screening from 2015 to 2019. the materials included total of 3,195 rice germplasm and breeding lines, out of which bangladesh rice research institute (brri) developped 2, 295 germplasms, 193 advanced breeding lines from brri, and 707 advanced breeding lines from international rice research institute (irri), philippines. from this study, the genotypes were categorized as 122 tolerant, 220 moderately tolerant, 1,207 sensetive, and 1,646 highly sensetive. among the brri germplasms, most of the materials (61%) had sensitive responses against salinity, while only 2 and 3% of rice germplasm exhibited tolerant and moderately tolerant, respectively. brri lines comprised 44% sensetive and 35% highly sensetive rice genotypes. in the tolerance level, 4% appeared as tolerant and 17% moderately tolerant against salinity. likewise, irri lines also showed relatively higher tolerance (9%) than the brri germplasm and lines. they were classified into 9 % tolerant and 16 % moderately tolerant rice genotypes. introduction among abiotic stresses, salinity is the second most destructive constraint on rice production after drought, affecting approximately 1 billion hectares of land worldwide (fageria et al., 2012). rice is relatively more sensetive to salt stress in seedling and early vegetative stages (lutts et al., 1995; mondal et al., 2020) and later at the reproductive phage (singh et al., 2010). sodium chloride (nacl) is dominant in saline soils among many salt contaminants and is readily soluble in water to yield toxic ions like sodium (na+) and chloride (cl–). roots of higher plants absorb readily smaller molecule, na+, and ultimately translocate to all plant parts causeingionic imblance, osmotic stress, and nutritional imbalance in rice plants (siringam et al., 2011; barua et al., 2015). direct salt accumulation disrupts metabolic processes and all major morpho-physiological and yield-related features, including tiller number, panicle length, spikelet number per panicle (khatun et al., 1995), grain filling (rao et al., 2013), plant biomass (zeng et al., 2007), and photosynthesis (baker, 2008), resulting drastically yield reduction. an essential tool for managing the rice field's salinity problem is integrating plant tolerance and cultural practices. therefore, development of salt-tolerant high-yielding rice genotypes can be the best attempt to cultivate salinity-affected areas (hakim et al., 2014). rice landraces play a prominent role in attaining local food security and serve as an excellent genetic reserve for rice genomics upgrading (tang et al., 2002). screening of rice germplasm for salt tolerance at the early seedling stage relies on genetic potentiality and seedling vigor under salinity stress. to widen the genetic base, the reliable use of the best sources, identifying a larger number of genotypes mailto:satyen1981@gmail.com mailto:avijitbrri@gmail.com.com 38 biswas et al. under salt stress is necessary. thus, the screening program was undertaken to determine performances of different rice germplasm and advanced breeding lines of both brri and irri against salt stress that can be used as donors in the salinity tolerance breeding program. materials and methods plant materials seeds of rice genotypes were received from plant breeding division, genetic resource and seed division, biotechnology division and hybrid rice division, brri, bangladesh and irri, philippines. an initial evaluation of 3,258 rice genotypes consisting of 2295 bangladeshi germplasm (mostly old indigenous genotypes), 193 advanced breeding lines developed by brri, 707 advanced breeding lines introduced from irri and 62 line/variety from other sources was conducted. beside, pokkali, nona bokra andir 58443-6b-10-3 were used as tolerant check variety and ir29 and irri 154 were used as salt-sensitive check varieties. experimental condition the experiment was done at the greenhouse of the plant physiology division, brri from 2015 to 2019. all the rice germplasms were screened at the seedling stage for salt tolerance in the hydroponics system using irri standard protocol (gregorio et al., 1997). at first, seedlings were raised in the hydroponic system using yoshida nutrients solution with ec level 12 dsm-1 under the laboratory conditions. yoshida nutrient solution comprised macronutrients and micronutrients and was prepared as suggested by yoshida et al. (1976). fig. 1. rapid screening technique for rice genotypes under salinity stress in hydrophonic systems using plastic trays (1= styrofoam ready for seed sowing, 2 = seed sowing, 3 = seedling growing in saline water 4 = experiment is ready for salinity scoring). the screening of rice genotypes for salt tolerance at the seedling stage was conducted in the hydroponics system (gregorio et al., 1997), which is termed as a rapid screening technique that uses plastic trays with tight-fitting thermocol support platform with holes for placing the seeds (figure 1). seeds were sown in the nylon mesh set just below the thermocol platform. before the greenhouse experiment, the seeds were disinfected with naocl solution (200 ml nacl in 1-litre water) and incubated for 48 hours to enhance germination. one pre-germinated seed was sown in each hole of phenotyping rice germplasm associated with salinity tolerance under hydroponics system 39 styrofoam seedling float and the seedling floats were then covered with a lid for 2 to 3 days to promote germination in the dark. the tap water was replaced with yoshida nutrient solution after three days of seeding. salinization was done seven days after sowing. after seven days, salinity was developed by adding crude salt to obtain an ec of 12 dsm-1. the yoshida solution's volume was adjusted to touching the seedling float at two days intervals. the ph was adjusted to 5 and ec was also adjusted with 12 dsm-1 synchronizing with the yoshida solution. when ec was higher than 12 ds m-1, tap water was applied to the solution, and nacl was added when ec was lower than 12 ds m-1. alikely, 1 n hcl was added to the solution when it’s ph was more than 5.0 and 1 n naoh was added when ph was less than 5.0. scoring of rice germplasms and breeding lines based on the visual symptoms like reduced leaf area, changing of lower leaves into whitish color, leaf tip death and leaf rolling, the rice seedlings were categorized as highly tolerant, tolerant, moderately tolerant, sensetive and highly sensetive (table 1). the standard saline tolerant genotypes, pokkali, nona bokra, ir 58443-6b-10-3 and saline sensetive genotype ir29 and irri 154 were used for test comparison. plants were exposed to salinity until the sesetive check variety died. after that rice genotypes were compared with both sesetive and tolerant check variety. if the phenotypes of any plants close to tolerant check variety were identified and the tested genotype as tolerant genotypes close to sensetive check variety e identified the tested genotype as sensetive genotype. the visual scoring for salinity tolerance was done by standard evaluation system (ses) score developed by gregorio et al. (1997). experimental design and analysis experimentals were crried out by following rcbd design with three replications. data analyses were performed using statistical tool for agricultural research (star), version 2.0.1, developed by international rice research institute (star, 2013). table 1. modified standard evaluation score (ses) of visual salt injury at seedling stage (gregorio et al., 1997) score observation tolerance 1 normal growth, no leaf symptoms highly tolerant 3 nearly normal growth, but leaf tips or few leaves whitish and rolled tolerant 5 growth severely retarded; most leaves rolled; only a few are elongating moderately tolerant 7 complete cessation of growth; most leaves dry; some plants drying sensetive 9 almost all plants dead or dying highly sensetive results a total of 3,195 rice germplasms were screened during five-years-period, 2015–2019 (table 2). out of these, 2,295 sources, germplasm were collected from genetic resources and seed division, brri, 193 advanced lines from the plant breeding division, brri and 707 advanced lines from the irri. the response of the rice varieties against salinity is presented in table 2. table 2. the number of rice genotypes rated for salinity tolerance in brri, gazipur, bangladesh from 2015-2019 sources response to salinity total t mt s hs brri germplasm 48 72 774 1,401 2,295 40 biswas et al. brri lines 8 33 84 68 193 irri lines 66 115 349 177 707 total 122 220 1,207 1,646 3195 t = tolerant; mt= moderately tolerant; s = sensetive; hs = highly sensetive from the above study, 125 tolerant, 225 moderately tolerant and 1,245 sensetive and 1,662 highly sensetive germplasms were identified from four different rice grmplasmsources. of the 2,295 genotypes of brri germplasm, 1401 were highly sensetive, and only 48 entries were tolerant to salinity stress (table 2). in brri lines, the higher number of rice genotypes (84) was sensetive, and only eight entries were found tolerant to salinity from a total of 193 advanced breeding lines. similarly, 349 rice genotypes were scored as sensitive and 66 genotypes exhibited tolerance to salinity from 707 advanced breeding lines developed in irri. the percentage of tolerant, moderately tolerant, sensetive, and highly sensitive rice genotypes varied greatly among three different sources of rice genotypes, including brri germplasm, brri lines, irri lines, and others (figure 2). fig. 2. percentage shared by each source of rice genotype groups, including brri germplasm (n=2295), brri lines (n=193), irri lines (n=707). most of the brri germplasms are 40 ensitive (34%) and highly sensitive (61%) to salinity stress and only 2 and 3% of genotypes were tolerant and moderately tolerant, respectively. on the other hand, brri developed advanced breeding lines comprised of 44% 40 ensitive and 35% highly 40 ensitive. in terms of tolerance, 4% appeared as tolerant, and 17% moderately tolerant against salinity stress. like brri germplasm and brri lines, irri lines also had a higher percentage of sensitive (50%) materials. but irri lines had relatively higher tolerance with a figure of 9% tolerant and 16% moderately tolerant rice genotypes. taking into accounts, brri lines and irri lines had higher cumulative frequency of tolerant genotypes ranging from 21 to 25% tolerant and moderately tolerant rice genotypes. the potentiality of different sources of rice genotypes against salinity stress in the present study, screened 3,195 rice genotypes for salinity tolerance. in each group of genotypessources, most of the materials were found sensetive to salinity stress with very few tolerant genotypes. out of 2,295 germplasms, only 48 rice genotypes scored three (3) based on the performance against salinity stress in greenhouse conditions (table 3). table 3. list of 48 rice genotypes from brri germplasm with ses score 3 evaluated during 2015 to 2019 at brri, gazipur, bangladesh name of the genotypes ses hashakumira, bhobanibhog, bhawalia, kumari amon, kolom, lal kumari, pura binni, 3 phenotyping rice germplasm associated with salinity tolerance under hydroponics system 41 kajal kori, binni, khama rang, temboro, lembur, chan moni, murali (2), beti balam, patnai (3), lati sail, nedukenari, raja morol, kajol gouri, jamrishaity, ausbaku, kachra boron, modu sail, binna chupi, ful kumari, raja sail tapl -14, radha, gutiswana, fazla (nawgan), kajal (nawgon), dudkalam, sadamota, lamba vojon, kali binni, kalobirun, boainchabiruim, moinamoti, boleshwas, bambudhan, changaidhan, kalo sail, gaindha, hijoldhiga, munsur, nona khorchi, hoglapata, benapol(brown) from a total of 193 brri lines developed at brri, only eight advanced breeding lines rated score(ses) three (3) based on screening results against salinity stress in greenhouse conditions (table 4). among the tested genotypes, most of them were sister lines and originated from the same crosses. table 4. list of 8 rice genotypes from brri lines with ses score 3 in evaluations conducted from 2015 to 2019 name of the genotypes ses br7091-4r-1, br7098-4r-2, br7100-r-6-6, br7102-4r-1, br7105-4r-2, br71095r-4, br7113-4r-1, br9539-b-12-11-13 3 like brri lines, irri lines also showed potentiality with a better performance against salinity stress. sixty-six advanced breeding lines ranked score (ses) three (3) based on screening results against salinity stress in greenhouse conditions from a total of 707 irri lines produced at irri, philippines (table 5). table 5. list of 66 rice genotypes from irri lines with ses score 3 conducted during 2015 to 2019 at brri, gazipur, bangladesh name of the genotypes source ir15t1409, ir15t1473, ir90477-74-1-2-3, ir106469-23-3-ajy1-b-1, ir108174-bcmu 10-1-b-1, ir126952-1699-41-8-10-9, ir126952-28-55-9-3-15-b, ir126952-2912-508-10-5, ir126952-29-27-58-1-2, ir126952-29-85-275-20-1, ir66946-3r-178-1-1, ir89330-14-3-12-2-3, ir89331-32-3-1-3-2-2, ir90477-74-1-2-3-2-ajy, ir91669-16-32-2-2, ir92860-33-cmu 1-1cmu 2-ajy b, ir09t484, ir87916-4-1-2-1-1-b, ir87938-1-1-1-2-1-3-b, ir87938-1-1-3-2-1-b, ir87938-1-2-2-1-3-b, ir87938-1-2-2-21-b, ir15t1324, ir15t1408, ir15t142, ir15t1466, ir58443-6b-10-3, ir63307-4b-43, ir65833-4b-17-1-3, ir66946-3r-178-1-1, ir69992-ac2, ir69997-ac2, ir70870-bp-25-2, ir72579-b-3-2-3-14, ir72579-b-3-2-3-8, ir72593-b-13-3-3-1, ir72593-b-182-2-2, ir72593-b-3-2-2-2, ir77674-5-1, ir83416-7-b-12-3-1-3-ajyi-b, ir87831-3-11-2-2-bayb, ir87870-6-1-1-1-1-b, ir87872-7-1-1-2-1-b, ir87888-3-ajyi-b, ir14t106, ir15t1074, ir15t1106, ir15t1107 3 discussion in rice, significant genetic diversity in salt stress tolerance is available. combining superior alleles from various sites, the availability of multiple breeding tolerance sources and gene exploration can further extend the genetic base and increase the degree of tolerance (rahman et al., 2016). identified 48 new potential donors for salt tolerance. these new sources show similar tolerance to the previously identified donors commonly used pokkali group and nona bokra. these landraces are currently being cultivated by farmers in the salt-affected areas of the coastal region of south bangladesh and west bengal,india despite their poor grain quality and lower yield. they could also be useful for varietal improvement with conventional breeding tools and new qtls/genes sources for molecular breeding. in the present study, screened 3,195 rice germplasms for salinity tolerance, and most of the materials were collected from the brri germplasm center. in each group of germplasms sources, the majority of the materials were found sensetive to salinity stress. rice has been grouped as a salt-sensitive cereal, especially at its early stage (lutts et al., 1995). from a total of 2,295 germplasm materials, only 120 42 biswas et al. rice genotypes scored (ses) 3 to 5 based on performance against salinity stress in greenhouse conditions with very few tolerant genotypes. in addition to characterizing physiological responses to salt stress, advances have been made in identifying quantitative trait loci (qtls) and genes controlling salinity tolerance traits. for example, several qtls for salt tolerance have been identified in rice, including a major locus on chromosome 1, comprising the major locus saltol obtained from pokkali (bonilla et al., 2002) and skc1 (oshkt1;5) from nona bokra. the saltol locus is involved in na/k homeostasis under salt stress (platten et al., 2013). these qtls improve the salinity tolerance of modern high-yielding varieties (hyv) but do not provide complete tolerance in modern hyv background. thomson et al. (2010) conducted experiment to identify and combine genes and qtls controlling different physiological mechanisms at both the seedling and reproductive stages to rapidly develop rice varieties that can produce higher and more stable yields under high salt stress conditions. further, identified other salinity tolerant genesfrom different sources. by pyramiding, these genes may provide more salinity tolerance in hyv background. it is reported that, seven landraces viz., akundi, ashfal, capsule, chikirampatnai, jataibalam, kalarata and kutipatnai had accumulated less na and comparatively more k, retaining a lower na/k ratio in the leaves (rahman et al., 2016). they essentially restrict the transport of sodium to the shoot. along with rice germplasm screening, also screened advanced breeding lines developed in salinity tolerance breeding programs both from brri and irri. to develop high-yielding salt-tolerant varieties, screened a total of 193 brri lines developed at brri. only 41 advanced breeding lines scored (ses) 3 to 5 based on screening results against salinity stress in greenhouse conditions. among them, most of them were sister lines and originated from the same cross. among tested brri lines, some good breeding lines were promoted as salt-tolerant rice varieties. based on better performance and higher grain yield in actual salinity areas, the advanced breeding lines br5999-82-3-2-hr1, br7105-4r-2, and br7100-r-6-6 were released as brri dhan54, brri dhan61, and brri dhan67, respectively from brri. brri dhan67 can tolerate 8 ds m-1 salinity (brri, 2018) with grain yield of 6.2 t ha-1 yield at south bangladesh under high salinity regime. brri researchers has developed a high-yielding salt-tolerant variety csr23 (also called as iet13769), which can tolerate ph 2.0±10.0 and salinity up to 8 ds m-1(singh et al., 2006). csr23 is better in k+ uptake and na+ exclusion and suitable for the majority of coastal regions. like brri lines, irri lines also showed relatively more potentiality with a better performance against salinity stress. one hundred and eighty-one advanced breeding lines ses score ranked 3 to 5 based on screening results against salinity stress in greenhouse conditions from a total of 707 irri lines produced at irri. recently, a salt-tolerant transgenic line from ir64 variety with overexpressing pcino1 from halophytic wild rice called porteresia coarctata has been developed. p. coarctata is a landrace in india, sri lanka, bangladesh and myanmar. transgenic rice tolerates upto 200 mmoll-1 salt or higher concentration in pots by inositol production under saline conditions and shows normal growth and grain yield under greenhouse conditions (mukherjee et al., 2019). among the promising irri developed breeding lines, ir63307-4b-4-3 and ir78761-b-satb1-28-3-26 were released as brri dhan47 and brri dhan73. the ideal salinity tolerant variety should possess tolerance to the high amount of na+, control the uptake of na+ and keep high uptake of k+, good initial vigor, agronomically superior with high yield potential. before the yield trial, these breeding lines were subjected to screening against salinity in greenhouse conditions and they exhibited a score (ses) 3 during the screening period. these results suggested that the screening results effectively identify promising materials from a large set of accessions. salinity tolerance is a complex trait in rice and controlled by polygenes. as a whole, the identified tolerant rice genotypes from three different sources might have potentiality in developing advanced breeding lines with improved salinity tolerance in rice. pokkali and nona-bokra and their derived lines have been widely used as saline tolerant donors in developing saline tolerant rice varieties and identifying candidate genes against salinity (rahman et al., 2016). recent advances in genomics also suggested the javascript:; phenotyping rice germplasm associated with salinity tolerance under hydroponics system 43 use of diverse parents in developing elite lines from germplasm. moreover, this study's identified materials may serve as a key founder in producing breeding lines with improved salinity tolerance. conclusion screening and identification of new tolerant breeding lines is a continuous work. in the present study, extensive scale screening of rice seedlings was performed against major abiotic stress, salinityto identify promising genetic materials and sources. however, much effort is required to develop tolerance breeding lines across the whole life cycle specially in reproductive stage. in the future, promising materials from the identified set may be tested in both the seedling and reproductive stages. acknowledgment this research received no external funding. we would like to acknowledge necessary support and seed suply provided by the plant breeding division and genetic resources and seed division, bangladesh rice research institute. references baker, n.r. 2008. chlorophyll fluorescence: a probe of photosyn thesis in vivo. ann. rev. plant biol. 59: 89–113. bangladesh bureau of statistics (bbs). 2016. yearbook of agricultural statistics 2015, ministry of planning. government of the people's republic of bangladesh. pp.49-58. bangladesh rice research institute (brri). 2018. adhunik dhaner chas. 21st edition. brri, bangladesh. pp.58-62. barua, r., m. de ocampo, j. egdane, a. m. ismail, and mondal, s. 2015. phenotyping rice (oryza sativa l.) genotypes for physiological traits associated with tolerance of salinity at seedling stage. sci agric. 12: 156-162. bonilla, p., j. dvorak, d. mackill, k. deal and g. gregorio. 2002. rlfp and sslp mapping of salinity tolerance genes in chromosome 1 of rice (oryza sativa l.) using recombinant inbred lines. philippines agric. sci. 85: 68–76. fageria, n.k., l.f. stone and a.b. santos. 2012. breeding for salinity tolerance. in: r fritsche-neto, a borém (eds) plant breeding for abiotic stress tolerance. springer-verlag berlin: heidelberg, pp.103–122. gregorio, g.b., d. senadhira and r.d. mendoza. 1997. screening rice for salinity tolerance, irrl discussion paper series no. 22. hakim, m.a., a.s. juraimi, m.m. hanaf, m.r. ismail, a. selamat, m.y. rafii and m.a. latif. 2014. biochemical and anatomical changes and yield deduction in rice (oryza sativa l.) under varied salinity regimes, biomed res. intl. article id 208584, https://doi.org /10.1155/ 2014/ 208584res. khatun, s., c.a. rizzo and t.j. flowers. 1995. genotypic variation in the effect of salinity on fertility in rice. plant soil. 173: 239–250. lutts, s., j.m. kinet and j. bouharmont. 1995. changes in plant response to nacl during development of rice (oryza sativa l.) varieties differing in salinity resistance. j. exp. bot. 46(12): 1843–1852. mondal, s., j. hasan, p. l. biswas, e. ahmed, t. halder, m. p. ali, a. khatun, m. nasim, t. islam, e. s. ella and e. m. septiningsih. 2020. nitrogen use efficiency in rice under abiotic stress: plant breeding approach", in recent advances in rice research. london, united kingdom: intechopen, doi: 10.5772/intechopen.94038. 44 biswas et al. mukherjee, r., a. mukherjee, s. bandyopadhyay, s. mukherjee, s. sengupta, s. ray and a.l. majumder. 2019. selective manipulation of the inositol metabolic pathway for induction of salt tolerance in indica rice variety. sci. rep. 9(1): 5358. doi: 10.1038/s41598-019-41809-7. platten, j.d., j.a. egdane and a.m. ismail. 2013. salinity tolerance, na+ exclusion and allele mining of hkt1; 5 in oryza sativa and o. glaberrima: many sources, many genes, one mechanism? bmc plant biol. 13: 32. rahman, m.a., m.j. thomson, m. shah-e-alam, m. de ocampo, j. egdane and a.m. ismail. 2016. exploring novel genetic sources of salinity tolerance in rice through molecular and physiological characterization. ann. bot.117(6): 1083-97. rao, p.s., b. mishra and s.r. gupta. 2013. effects of soil salinity and alkalinity on grain quality of tolerant, semi-tolerant and sensitive rice genotypes. rice sci. 20: 284 –291. singh, r.k., b. mishraand g.b. gregorio. 2006. csr23: a new salt tolerant rice variety for india. int. rice res. notes, 31(1): 16-18. singh, r.k., e.d. redoña and l. refuerzo. 2010. varietal improvement for abiotic stress tolerance in crop plants: special reference to salinity in rice. in: pareek, a., s.k. sopory, h.j. bohnertandgovindjee, editors.abiotic stress adaptation in plants. springer, dordrecht, pp.387–415. siringam, k., n. juntawong, s. cha-um, and c. kirdmanee. 2011. salt stress induced ion accumulation, ion homeostasis, membrane injury and sugar contents in salt-sensitive rice (oryza sativa l. spp. indica) roots under iso-osmotic conditions. afr. j. biotechnol. 10: 1340–1346. tang, s.x., y.z. jiang, x.h. wei, z.c. li and h.y. yu. 2002. genetic diversity of isozymes of cultivated rice in china. acta agron. sin. 28: 203–207. tang, t., j. lu and j. huang. 2006. genomic variation in rice: genesis of highly polymorphic linkage blocks during domestication. plos genet. 2: 1824–1833. thomson, m.j., m. de ocampo, j. egdane. 2010. characterizing the saltol quantitative trait locus for salinity tolerance in rice. rice 3: 148–160. zeng, y., h.z. zhang, l. shen, s.j. sun, m. wang, d. liao, x. liu, x. wang, f. xiao and g. wen. 2007. evaluation of genetic diversity of rice landraces (oryza sativa l.) in yunnan, china. breed. sci. 57: 91–99. bangladesh agron. j. 2023, 26(1): 56-74 efficacy of herbicide mixtures for transplanted aman rice in silty clay loam soil of bangladesh zobayra haque jame1, taslima zahan2, h. m. m. tariq hossain1, promita shikha roy3 and sheikh muhammad masum1* 1department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh 2on-farm research division, bari, gazipur-1701, bangladesh 3baligaon amzad ali college, tongibari, munshigonj, bangladesh *corresponding author, email: smmasum607@yahoo.com (received: 13 july 2023, accepted: 30 august 2023) keywords: chemical control, mixture herbicide, rice, weed, yield abstract weed management plays an important role in obtaining target yield. a field experiment was carried out at the agronomy field of sher-e-bangla agricultural university, dhaka, bangladesh, from july to december 2019 to get the most effective weed control strategy for transplanted aman rice. the soil of the study field was silty clay loam in nature. the study consisted of two factors i.e., variety (4: chinigura, br11(mukta), brri dhan56, and brri hybrid dhan6) and herbicide (4) viz., bispyribac-sodium wp @ 150 g ha-1, acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1, pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1, and weedy check as a control. the experiment was laid out in a split-plot design with three replications. thirteen weed species were found in the experimental plots, mostly broadleaf and sedge. monochoria vaginalis was the most dominant weed species. the study noticed that the application of mixed herbicides offered better weed control over single herbicide application. application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 significantly reduced weed density and biomass and was the best way of controlling complex weed flora. the study marked out br11 (mukta) as the most potential aman rice variety to produce the highest yields at applying acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1. this treatment gave the highest gross return (tk. 1,46,010), net return (tk. 88,699), and benefitcost ratio (2.55). therefore, the study suggests the application of mixed herbicides and br11 (mukta) to get the optimum yield of transplanted aman rice and maximum economic benefit. introduction rice (oryza sativa l.) is bangladesh's major growing crop, mostly grown in three seasons viz. aus (pre-monsoon), aman (monsoon or rainy season) and boro (dry season) rice. among the three growing seasons, the area coverage of aman rice is the highest (67% of the cropped area of 85.77 hectares). in 2020, the amount of land used for hyv varieties was 44.47 lakh (4.44 million) hectares, hybrid 2.40 lakh (0.24 million) hectares, local varieties 7.15 lakh (0.75 million) hectares, and for broadcast aman 3.12 lakh (0.31 million) hectares of cultivable land. the total land under the aman rice was 57.14 lakh (5.71 million) hectares (magzter, 2021). in 2019–20, about 88% was planted to modern varieties, with traditional landrace varieties covering 12% (bbs, 2019). the average rice yield of bangladesh is almost 50% less than the world's average yield (rahman et al., 2023). therefore, to boost rice yield and production, attempts must be made to increase the yield per unit area by adopting modern rice varieties and applying improved technology and management practices (such as irrigation, spacing, weed, insect, etc.) weed is the most important threat to the upland or aerobic rice systems, resulting in yield losses between 30 and 98% (ramana et al., 2014). the high competitive ability of weeds exerts a serious negative effect on crop production. among the harmful pest, weeds contribute to maximum losses in crop production, potentially reducing crop production by 34%, followed by animal pests (18%) and pathogens by 16% (abbas et al., 2018). although hand weeding is a performance of herbicide mixture for t.aman rice 57 popular weed control method, the unavailability of labour during the peak period discourages farmers from choosing this method. mechanical weeding and chemical weed control are the alternatives to hand weeding. in the last few years, chemical weed control has increased (ahmed et al., 2014) because of getting quick and site-specific weed control at a low cost compared to traditional control methods (zahan et al., 2018). using herbicides is a promising alternative for controlling weeds (rahman, 2016). however, continuous and indiscriminate use of herbicides may alter their degradation and pose persistence problems due to residual effects beyond harvest, threatening health and ecology. the use of herbicides with different modes of action and chemistry is desirable to reduce the problem of residue build-up, a shift in weed flora (rajkhowa et al., 2006), and the development of herbicide resistance in weeds (rao et al., 2007). herbicide mixture may be one option for managing or delaying cross-resistance development in weeds against herbicides (dhawan et al., 2009). different pre-mix and tank-mix combinations are being tried to control mixed types of weeds in one go (yadav et al., 2008), reducing the total volume of herbicide and easing and economizing its application. zahan et al. (2021) found that sole dependence on herbicides having a single mode of action is not advisable. it can contribute to weed species shifting towards difficulty to control and the rapid evolution of multiple herbicide resistance, which threatens wheat production. bharat and kachroo (2007) reported that tank mix application of fenoxaprop+ metribuzin (120+100 g ha−1, sulfosulfuron + 2, 4-d (25 + 500 g ha−1), clodinafop + metsulfuron methyl (60+2 g ha−1, isoproturon + 2, 4-d (1000 + 500 g ha−1) and metribuzin (175 or 200 g ha−1) significantly reduced both grass and broadleaf weeds. applying two or more herbicides simultaneously, using pre-package mixtures, or mixing different herbicide products before the applications, is a prevalent approach in chemical weed control. some mixed herbicides are usually available in our country and worldwide, such as bensulfuron methyl + acetachlor, bensulfuron methyl + pretilachlor, bensulfuron methyl + butachlor, bensulfuron methyl + mefenacet, bensulfuron methyl + quinclorac, bensulfuron methyl + cyhalofop-butyl + fecoxaprop-p-ethyl, bispyribac sodium, butachlor + propanil, carfentrazoneethyl + isoproturon, ethoxysulfuron + fluazifop-p-ethyl, fenoxaprop-p-ethyl + ethoxysulfuron, etc (bcpa, 2020). currently, the use of mixed herbicides against weeds in transplanted aman rice has increased its effectiveness daily. rice varieties colossally affect the development and pervasion of weeds in the field. typically short-height varieties face more weed infestation than taller ones (tshewang et al., 2016). thus, an appropriate variety ought to be chosen to keep away from the weed rivalry and get the greatest yield from rice. high-yielding rice varieties are now more available than conventional ones (shew et al., 2019). even the growth process of rice plants under different agro-climatic conditions differs with rice varieties (alam et al., 2012). moreover, zahan et al. (2017) reported that the response of transplanted aman rice varieties differs with herbicides. therefore, the performance of herbicides also could vary with the aman rice varieties. some herbicide mixtures have been launched in bangladesh for wide-spectrum weed control in transplanted rice. but the information on their efficacy against weeds in transplanted rice varieties is very meager in the literature. therefore, the study evaluated the performance of transplanted aman rice varieties and found the most efficient mixed herbicide(s) with the best yield providing aman rice varieties. materials and methods the study was done at the agronomy field of sher-e-bangla agricultural university (sau), dhaka, bangladesh. the experimental site is geographically situated at 23°77ʹ n latitude and 90°33ʹ e longitude at an altitude of 8.6 meters above sea level. the experimental field belongs to the agro-ecological zone (aez) of “the modhupur tract”, aez-28. the land was fairly leveled highland. the soil of the experimental site was silty clay loam in texture belonging to the tejgaon 58 jame et al. series having ph 5.8–6.5 and ece 25–28 at 0-15 cm soil depths. the experiment was conducted in the rainy (aman) season from july to december 2019. usually, the experimental site was under the subtropical climate and was characterized by high temperature, high humidity, and heavy precipitation with occasional gusty winds from march to august; however, scanty rainfall was associated with moderately low temperature. the detailed meteorological data of monthly averaged maximum and minimum temperature, relative humidity, and total rainfall during the experimentation period are given in table 1. table 1. monthly average of maximum and minimum temperature and the monthly total rainfall during the study period (july to december 2019) month air temperature (˚c) relative humidity (%) total rainfall (mm) maximum minimum july’19 32.6 26.8 81 114 august’19 32.6 26.5 80 106 september’19 32.4 25.7 80 86 october’19 31.2 23.9 76 52 november’19 29.6 19.8 53 00 december’19 28.8 19.1 47 00 source: metrological centre, (climate division), bangladesh meteorological department, agargaon, dhaka the study considered two factors as treatments, i.e., variety 4: chinigura, br11(mukta), brri dhan56, and brri hybrid dhan6 and herbicide 4: bispyribac-sodium wp @ 150 g ha−1, acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1, pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1, and weedy check as a control. the experiment was laid out in a splitplot design with three replications. in the main plot, there was herbicide treatment, and variety was in the subplot. there were 16 treatment combinations and 48 unit plots. the unit plot size was 5.04 m2 (2.8 m×and 1.8 m). the blocks and unit plots were separated by 1.0 m and 0.50 m spacing, respectively. herbicides were applied to each plot at par with the treatment requirement by a knapsack hand sprayer. in the case of weedy check plots, weeds were allowed to grow along with the crop throughout the crop season and no control measures were adopted to check the weeds. the weed flora present in the weedy check plots was noted. the tested varieties' healthy and disease-free seeds were collected from bangladesh rice research institute (brri). before raising seedlings, sprouted seeds of all the rainy season (aman) rice varieties were planted in the seedbeds, and 25-day old seedlings were transplanted in the main field on july 8, 2019 following the standard procedures. detailed information on the tested herbicides is given in table 2. table 2. details of the tested herbicides in aman rice herbicide trade name with registered company mode of action rate of application time of application (dat) bispyribac-sodium xtrapower 20wp; aci crop care ltd. inhibits plant amino acid synthesis – acetohydroxyacid synthase (ahas) 150 g ha−1 20 acetochlor 14% + bensulfuron methyl 14% ayna plus-18wp; jass agro ltd. inhibits cell division in the shoots and roots of the plant 750 g ha−1 12 pretilachlor 6% + pyrazosulfuron 0.15% upleros; aci crop care ltd. inhibits acetolactate synthase 9.88 kg ha−1 3 the experimental land was fertilized with n, p, k, s, and zn at 69, 20, 35, 11, and 2 kg ha-1 in the forms of urea, triple super phosphate, muriate of potash, gypsum, and zinc sulphate, respectively. all of the fertilizers except urea were applied as basal doses at the time of final land preparation. urea was applied in three equal splits: the first split at 21 days after transplanting (dat), the second split was top dressed at 45 dat (active vegetative stage), and the third split was applied at 60 dat (panicle initiation stage). irrigation was provided up to 5 cm in each plot performance of herbicide mixture for t.aman rice 59 according to the critical stages of rainy season rice. regular observations were made to see the growth and visual differences of the crops due to the treatments applied in the experimental field. weed density and dry matter were recorded from 1 m2 of the area at 30 and 60 days after transplanting of rainy season rice. after counting the numbers, fresh weeds were oven dried at 80° c until a constant weight was obtained. the sample was then transferred into desiccators and allowed to cool down to room temperature, and the final weight of the sample was taken. relative weed density, weed control efficiency (wce), weed control index (wci), crop growth rate (cgr; mg cm-2 day-1), relative growth rate (rgr; mg g-1 day-1), and net assimilation rate (nar; mg cm-2 day-1) were calculated following the below-mentioned formula. (i) relative weed density (%) = number of individuals of same species number of individual of all species × 100 (mishra, 1968) (ii) wce = weed population in control−weed population in treated plot weed population in control × 100 (mani et al., 1973) (iii) wci = weed dry weight in control−weed dry weight in treated plot weed dry weight in control × 100 (mishra and tosh, 1979) (iv) crop growth rate (cgr) = 𝑊2−𝑊1 𝑃(𝑡2−𝑡1) (watson, 1956) where, p = ground area (cm-2), w1 = dry weight per unit area at t1, w2 = dry weight per unit area, at t2, t1 = time of first sampling, t2 = time of second sampling (v) relative growth rate (rgr) = 𝐿𝑛(𝑊2)−ln(𝑊1) (𝑡2−𝑡1) (beadle, 1985) where, ln = natural log values, w1 = dry weight per unit area at t1, w2 = dry weight per unit area, at t2, t1 = time of first sampling, t2 = time of second sampling (vi) net assimilation rate (nar) = (𝑊2−𝑊1)( lnla2−lnla1) (𝑡2−𝑡1)( lnla2−lnla1) (gregory, 1926) where, la1 = leaf area of first sampling, la2 = leaf area of second sampling, w1 = dry weight per unit area at t1, w2 = dry weight per unit area at t2, t1 = time of first sampling, t2 = time of second sampling, ln = natural log values dry matter accumulation in rice plant (g) was recorded at 30, 45, 60, and 90 dat. the sample plants were oven-dried for 72 hours at 70°c, and then data were recorded from randomly selected plant samples plant−1 plot−1. the crop was manually harvested at the maturity of grains (when 80–90% of the grains were golden yellow). the harvesting dates of chinigura, br11, brri dhan56, and brri hybrid dhan-6 were november 29, 2019, november 22, 2019, november 08, 2019, and november 15, 2019, respectively. data on yield contributing characters were collected from ten (10) pre-selected hills plot−1 before harvesting the whole plot crop. grain and straw yields were recorded from the central area of 1 m2 of each plot and finally converted to t ha−1 after adjusting grain moisture content at 12%. the straw yield was recorded after sun-drying the straws properly. for cost and return analysis, input costs, overhead costs, and some common costs were considered (mian and bhuiya, 1977). in the input costs, all material costs and non-material costs were taken into consideration. in a day 8 working hours was considered for labour as a man's day with 400 tk. wage labour−1 day−1. the mechanical labour came from the tractor. a period of eight working hours for a tractor was taken to be tractor day. in the case of overhead cost, the value of land was taken tk. 200000 ha−1. the interest on this cost was calculated for 6 months @ tk. 12.5% per year based on the interest rate of the bank. the common cost was 5% of the total cost. the total cost of production, gross return, net return, and benefit-cost ratio was calculated from the following formula. 60 jame et al. total cost of production (tk. ha−1) = input costs (tk. ha−1) + overhead costs (tk. ha−1) + common cost (tk. ha−1) gross return from rice (tk. ha−1) = value of grain yield (tk. ha−1) + value of straw (tk. ha−1) net return (tk. ha−1) = gross return (tk. ha−1) – total cost of production (tk. ha−1) benefit cost ratio (bcr) = grossreturn (tk/ha) cost of production (tk/ha) the collected data were compiled and analysed statistically using the analysis of variance (anova) technique with the help of a computer package program named statistix 10 data analysis software and the mean differences were adjusted by the least significant difference (lsd) test at 5% level of probability. results and discussion the experimental field was infested by thirteen weed species with three grasses, three sedges, and seven broadleaf weed species and the most dominating species were broadleaf and sedge weeds (table 3). these weed species were belonging to the nine families of alismataceae, menyanthaceae, asteraceae, sphenocleaceae, pontederiaceae, onagraceae, papayeraceae, cyperaceae, and poaceae. the grasses were e. cruss-galli, eleusine indica, and e. colona, sedges were scirpus maritimus, cyperus diformis and c. rotundus, and broadleaved were, sagittaria guayansis, nymphoides cristatum, enydra fluctuans, sphenoclea zeylanica, monochoria vaginalis, ludwigia octovalvis, and marsilea quadrifolia. bhuiyan, and mahbub (2020) reported infestation of two types of grass, two sedges, and four broadleaves in the rice field belonging to the families of poaceae, cyperaceae, pontederiaceae, marsileaceae, sphenocleaceae, and asteraceae. the broadleaf weed species were m. vaginalis, marsilea minuta, s. zeylanica, and eclipta alba, grasses were e. crus-galli, cynodon dactylon, and sedges were c. difformis, and scirpus maritimus. yadav et al. (2008) also reported that the major associated weeds in rice field were e. glabrescens, and e. colona (l.) among grasses, ammannia baccifera l. and euphorbia sp. among broad-leaved weeds, and fimbristylis miliacea (l.) vahl, cyperus iria l., c. rotundus l., and c. difformis l. among sedges. bari et al. (1995) reported that the three important weeds of transplanted aman rice fields were f. miliacea, paspalum scrobiculatum, and lyperus rotundus. mamun et al. (1993) also reported that f. miliacea, lindernia antipola, and eriocaulen cenerseem were important weeds in transplant aman rice fields. table 3. weed flora of the experimental field in aman season during 2019 local name english name scientific name family habitat weed type chapra goose grass eleusine indica poaceae annual grass choto shama jungle rice echinochloa colona poaceae perennial grass boro shama barnyard grass echinochloa crus-galli poaceae annual grass holde mutha yellow nutsedge cyperus diformis cyperaceae perennial sedge mutha nutsedge cyperus rotundus cyperaceae perennial sedge cechra dwarf club-rush scirpus maritimus cyperaceae perennial sedge shusni shak european water clover marsilea quadrifolia papayeraceae perennial broadleaf chadmala duck weed sagittaria guayansis menyanthaceae perennial broadleaf helenca buffalo spinach enydra fluctuans asteraceae annual broadleaf jheel-morich gooseweed sphenoclea zeylanica sphenocleaceae annual broadleaf choto pani kochu pickerel weed monochoria vaginalis pontederiaceae perennial broadleaf pani long mexican primrose willow ludwigia octovalvis onagraceae perennial broadleaf species-wise weed population (no. m-2) and relative weed density (%) at 30 dat and 60 dat showed that there was a predominance of broadleaf and sedge weeds in weedy check plots (table 4). m. vaginalis was the most dominant weed (36 or 18 m-2 and 15.93, 16.98 %) at 30 and 60 dat followed by s. guayansis and c. rotundus weed species at 30 and 60 dat. while performance of herbicide mixture for t.aman rice 61 the dominancy of s. maritimus at least at 30 dat and m. quadrifolia at 60 dat was the least among all the weed species. table 4. species wise weed population (no. m-2) and relative weeds density (%) in weedy check plots at 30 and 60 dat scientific name weed population (no. m−2) relative weeds density (%) 30 dat 60 dat 30 dat 60 dat sagittaria guayansis 31 12 13.72 11.32 enydra fluctuans 18 8 7.96 7.55 sphenoclea zeylanica 22 9 9.73 8.49 monochoria vaginalis 36 18 15.93 16.98 ludwigia octovalvis 17 9 7.52 8.49 marsilea quadrifolia 7 2 3.10 1.89 scirpus maritimus 5 4 2.21 3.77 eleusine indica 10 6 4.43 5.66 echinochloa colona 13 9 5.75 8.49 cyperus diformis 23 9 10.18 8.49 cyperus rotundus 27 12 11.95 11.32 echinochloa crus-galli 7 3 3.10 2.83 weed density and dry matter effect of herbicides was significant on weed density and dry matter at 30 and 60 dat of rainy (aman) season rice (figure 1). results revealed that the highest weed density (26 and 14 m−2 at 30 and 60 dat) and maximum weed dry matter (8.02 and 5.36 g m-2 at 30 and 60 dat) was recorded in weedy check plot. on the other hand, acetochlor 14% + bensulfuron methyl 4% wp treated plot had the lowest weed density (2.33 and 1.78 m-2 at 30 and 60 dat) and minimum weed dry matter (1.78 and 1.00 g m−2 at 30 and 60 dat). this was due to the application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1 mix herbicide which might have prevented the germination of susceptible weed species and also reduced the growth of germinated weeds by inhibiting the process of photosynthesis comparable to other herbicide treatments. earlier studies also reported maximum weed density and dry matter in untreated weedy checks (mishra, 2019; suryakala et al., 2019). application of a mixture of herbicides offered 80% or even more control of annual and perennial weeds comparable to a single application of herbicide in the previous studies (mahbub and bhuiyan, 2018). fig. 1. effect of herbicide on (a) weed density and (b) weed dry matter at 30 and 60 days after transplanting of rainy (aman) season rice (here, h0=weedy check, h1=bispyribac sodium wp @ 150 g ha−1, h2=acetochlor 14%+ bensulfuron methyl 4% wp @ 750 g ha−1 and h3=pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1) a a b b d d c c 0 10 20 30 30 dat 60 dat w ee d d en si ty m -2 h0 h1 h2 h3 a ab bd d c c 0 2 4 6 8 10 30 dat 60 dat w ee d d ry w ei g h t (g m -2 ) h0 h1 h2 h3(b) (a) 62 jame et al. fig. 2. effect of variety on weed density and weed dry matter at 30 and 60 days after transplanting of rainy (aman) season rice (here, v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6) the variety had a significant effect on weed density and weed dry matter at 30 dat and 60 dat of rainy season rice (fig.2). the highest weed density m-2 (16.92 and 8.08 m-2 at 30 and 60 dat) and maximum weed dry matter (5.92 and 3.40 g m-2 at 30 and 60 dat) was counted from the chinigura rice variety. minimum weed density (10.19 and 4.95 m-2 at 30 and 60 dat) and dry matter (3.22 and 1.61 g m-2 at 30 and 60 dat) were observed in br 11 rice variety. the reason for getting a lower number of weeds in the high-yielding cultivar might be due to the vigorous growth of the cultivar helping to suppress weeds. afrin et al. (2015) also reported that competitive rice varieties viz., hybrids, usually have better vigour than inbreeds and effectively suppress the infestation of weed populations or density. the interaction effect of herbicide and variety was significant on weed density and dry matter at 30 and 60 dat (table 5). table 5. combined effect of herbicide and rice variety on weed density and weed dry weight m-2 of t. aman rice at 30 and 60 dat treatment weed density (m-2) weed dry weight (g m-2) 30 dat 60 dat 30 dat 60 dat h0v1 29.67±1.19a 16.34± 0.82a 9.70±0.39a 7.08±0.35a h0v2 20.00±0.8d 12.13±0.61c 6.51 ±0.26d 3.68±0.18d h0v3 27.33±1.09b 13.87±0.69b 9.27±0.37b 5.97±0.3b h0v4 25.00 ±1 c 12.3 ±0.62c 6.580±0.26d 4.71±0.24b h1v1 24.66±0.99c 7.33±0.37d 8.03±0.32c 2.73 ±0.14e h1v2 15.33 ± 0.61e 4.67±0.23g 4.01±0.16f 1.35±0.07h h1v3 23.33 ±0.93c 7.67±0.38d 5.83±0.23e 2.48±0.12ef h1v4 16.67 ± 0.67e 5.33±0.27f 4.12±0.16f 1.85±0.09g h2v1 4.33 ± 0.17h 3.66±0.18h 3.10±0.12g 1.79±0.09g h2v2 0.11 ± 0.01i 0.33±0.02k 0.81±0.03g 0.39±0.02j h2v3 4.33±± 0.17h 3.67±0.18h 1.86 ± 0.07i 1.02±0.051i h2v4 3.67 ± 0.15h 1.66±0.08j 1.31±0.05k 0.81±0.04i h3v1 9.01 ±0.36fg 4.99±0.25fg 2.85±0.11h 1.98±0.1g h3v2 5.33 ± 0.21h 2.66±0.13i 1.54±0.06jk 1.01±0.05i h3v3 9.34 ± 0.37f 6.00±0.3e 2.64±0.11h 2.40±0.12f h3v4 7.34 ±0.29g 2.99±0.15i 1.77±0.07ij 1.31±0.07h se 0.88 0.23 0.11 0.13 cv (%) 7.67 4.36 3.18 6.15 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability. here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14%+ bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1; v1 = chinigura, v2 = br 11, v3 = brri dhan56 and v4 = brri hybrid dhan6 a a c d a b b c 0 10 20 30 30 dat 60 dat w ee d d en si ty m -2 v1 v2 v3 v4 a ad d b bc c 0 2 4 6 8 30 dat 60 dat w ee d d ry w ei g h t (g m -2 ) v1 v2 v3 v4(b)(a) performance of herbicide mixture for t.aman rice 63 the results revealed that chinigura variety had the highest weed density (29.67 and 16.34 m-2 at 30 and 60 dat) and maximum dry matter (9.70 and 7.08 g m−2 at 30 and 60 dat) in the weedy check plots. while application of mixed herbicide, i.e., acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1 in br11 variety had the lowest weeds density (0.11 and 0.33 m−2 at 30 and 60 dat) and minimum weed dry weight (0.86 and 0.39 g m-2 at 30 and 60 dat). the variation in weed density and dry matter was due to the effective weed control offered by mixing herbicides and high-yielding rice cultivars compared to application of single herbicide with low-yielding rice varieties. weed control efficiency and weed control index application of herbicides significantly affects the weed control efficiency (wce) and weed control index (wci) of t. aman rice at 30 and 60 dat (figure 3). due to herbicide treatments, wce ranged from 22.1 to 88.9% and wci ranged from 32.4 to 82.5% over the weedy check plots. application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 offered higher wce and wci than the other treatments. however, all the herbicide treatments suppressed weeds, but the magnitude of suppression was higher in acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 treated plots (wce: 88.9 and 83.7 % and wci: 78.7 and 82.5% at 30 and 60 dat, respectively). the weedy check plot obtained the minimum wce and wci (0.0 % at both 30 and 60 dat). the differences in wce and wci of the herbicide treatments were due to the variations in weed density in treated plots that directly reflected the effect of herbicides on weeds. herbicides deteriorate the physiological and morphological features of weeds, help to reduce weed density and biomass, and increase weed control efficiency (bhuiyan and mahbub, 2020) and weed control index (suryakala et al., 2019). in the earlier study, mishra (2019) found that the weed control efficiency was higher with the application of bensulfuron methyl 60g ha-1 + pretilachlor 600 g ha-1 at 3 dat than hand weeding, which varies from 74% at 30 dat to 42.9% at 90 dat. this might be due to the effect of weeds during the initial stages of crop growth with herbicide application. priya and kubsad (2013) also reported higher weed control efficiency and lower weed index in herbicide treatments than weedy check owing to lower weed dry weight, higher weed control efficiency, and lower weed index due to effective control of complex weed flora. fig. 3. effect of herbicide on weed control efficiency and weed control index of t. aman rice at 30 and 60 days after transplanting (here, h0 =weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 =acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha1). rice varieties significantly affected wce and wci of t. aman rice at 30 and 60 dat (figure 4). wce ranged from 41.2 to 59.2%, and wci ranged from 39.0 to 56.3% with the varieties. experiment results revealed that cultivation of br11 rice variety cultivation recorded the maximum wce (49.0 and 59.2%) and wci (50.4 and 56.3%) at 30 and 60 dat while the cultivation of d d c c a a b b 0 20 40 60 80 100 30 dat 60 dat w ee d c o n tr o l e ff ic ie n cy (% ) h0 h1 h2 h3 d d c c a a b b 0 20 40 60 80 100 30 dat 60 dat w ee d c o n tr o l in d ex (% ) 64 jame et al. brri dhan56 rice variety cultivation recorded minimum wce (41.2 and 43.8 %) and wci (39.0 and 50.3%) at 30 and 60 dat. afrin et al. (2015) also found a similar result, who reported that different rice varieties significantly influenced weed control efficiency and index. chauhan and johnson (2011) reported that the weed control index could be attributed to less weed biomass due to the highly competitive variety's ability to suppress weeds. fig. 4. effect of variety on weed control efficiency and weed control index of t. aman rice at 30 and 60 days after transplanting (here, v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan) the combined effect of herbicide and rice variety significantly affected wce and wci at 30 and 60 dat (table 6). table 6. combined effect of herbicide and rice variety on weed control efficiency (%) and weed control index (%) of t. aman rice at 30 and 60 dat treatment combinations weed control efficiency (%) weed control index (%) 30 dat 60 dat 30 dat 60 dat h0v1 h0v2 h0v3 h0v4 h1v1 16.89±0.35h 55.12±1.84g 17.22±0.29h 61.44±1.23de h1v2 23.35±0.49g 61.50±2.05f 38.35±0.64g 63.32±1.27d h1v3 14.64±0.3h 44.73±1.49h 37.11±0.62g 58.46±1.17e h1v4 33.32±0.69f 56.81±1.89g 37.39±0.63g 60.79 ±1.22de h2v1 85.41±1.78b 77.60 ±2.59c 68.04±1f 74.72±1.49c h2v2 99.45±2.07a 97.28±3.24a 86.79±1.28a 89.31±1.79a h2v3 84.16±1.75b 73.54±2.45d 79.94±1.18b 82.92±1.66b h2v4 85.32±1.78b 86.55±2.88b 80.14±1.18b 82.87±1.66b h3v1 69.64±1.45d 69.44±2.31e 70.62±1.04e 72.03±1.44c h3v2 73.35±1.53c 78.04±2.6c 76.34±1.13c 72.65±1.45c h3v3 65.81±1.37e 56.74±1.89g 71.52±1.05de 59.80±1.2e h3v4 70.64±1.47cd 75.7±2.52cd 73.15±1.08d 72.12±1.44c se 1.39 1.72 1.17 1.56 cv (%) 3.78 4.05 3.14 3.61 in a column means having a similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at a 0.05 level of probabilit here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2= acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1, v1 = chinigura, v2 = br 11, v3 = brri dhan56 and v4 = brri hybrid dhan6 due to the combined effect of herbicide and rice variety, the wce ranged from 14.64 to 99.45% and wci ranged from 17.22 to 89.31% over the weedy check plot. application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 mixed herbicide along with br 11 c ca a d d b b 0 10 20 30 40 50 60 70 80 30 dat 60 dat w ee d c o n tr o l ef fi ci en cy ( % ) v1 v2 v3 v4 c ca a b db b 0 10 20 30 40 50 60 70 30 dat 60 dat w ee d c o n tr o l in d ex ( % ) performance of herbicide mixture for t.aman rice 65 rice variety recorded the maximum wce (99.5 and 97.3%) and wci (86.8 and 89.3%) at 30 and 60 dat. the reason might be related to the effect of the application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 in br11 that hampered weed growth and reduced weed number and biomass, and boosted up weed control efficiency and weed control index of this combined treatment. while the minimum wce and wci (0.0 and 0.0 %) at 30 and 60 dat was recorded in weedy check plots along with chinigura rice, and statistically similar results were also found in the weedy check plots along with br11, brri dhan56, and brri hybrid dhan6 rice cultivation. plant height plant height is an important morphological character that acts as a potential indicator of the availability of growth resources in its approach. the study results expressed that rice plant heights significantly varied with herbicide treatments (figure 5). the maximum plant height (40.1 cm) was recorded from acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 (h2) mixed herbicide treatment at 15 dat which was statistically similar with bispyribac sodium (40.0 cm) and significantly superior over remaining treatments. at 30 dat the maximum plant height (80.0 cm) was recorded from pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1which was statistically similar with (79.3 cm) acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1. the tallest plants (99.8, 117.3, 136.1, and 138.8 cm at 45, 60, and 90 dat, and at harvest, respectively) were recorded from acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 treated plots and statistically similar results were also obtained from bispyribac sodium treated plots, pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1 treated plots, and also from bispyribac-sodium treated plots. on the other side, acetochlor 14% + bensulfuron methyl 4% wp treated plots had the shortest plants (37.34 cm) at 15 dat which was statistically similar with pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots. however, the weedy check plots had the shortest plants at 15, 45, 60, and 90 dat, and even at harvest (72.8, 92.7, 113.3, 130.7, and 132.9 cm, respectively). at the earlier growth stage, spraying mixed herbicide in plants may produce a thin layer in the leaf surface area that might hamper photosynthesis, and as a result, dry matter accumulation and plant height get affected for a while comparable to the plants of no herbicide sprayed plots or weedy check plots. in the earlier study, das et al. (2017) reported that the application of herbicides did not show any phytotoxic symptoms on rice plants. however, teja et al. (2017) reported that the plant height of rice varied significantly with herbicide treatments. fig. 5. effect of herbicide on plant height of t. aman rice at different days after transplanting. here, weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14%+ bensulfuron methyl 4% wp @ 75 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1. a c c b b b a b a ab ab ab b a a a a a b a b a a ab 0 50 100 150 200 15 dat 30 dat 45 dat 60 dat 90 dat at harvest p la n t h ei g h t (c m ) h0 h1 h2 h3 66 jame et al. rice plant height was significantly differed with the varieties at different days after transplanting (figure 6). the results expressed that chinigura had the maximum plant height (45.60, 87.67, 107.99, 130.97, 155.24, and 158.18 cm at 15, 30, 45, 60, 90 dat, and, at harvest, respectively) while br11 had the minimum plant height (34.31, 64.58, 74.77, 80.61, 117.76, and 119.86 cm at 15, 30, 45, 60, 90 dat, and at harvest, respectively). the variation in plant height is probably due to the genetic makeup of the variety. salam et al. (2020) also observed a similar result and reported that the varieties significantly influenced plant height. fig. 6. effect of variety on plant height of t. aman rice at different days after transplanting rice plant height was significantly varied with the combined effect of herbicide and variety (table 7). table 7. combined effect of herbicide and variety on plant height at different after transplanting of aman rice treatments days after transplanting (dat) at harvest 15 30 45 60 90 h0v1 45±59±1.3 a 82.43±4.54 b 100.53±3.01 d 128.80±2.51 c-e 147.53± 9.31 b 149.33±6.67 c h0v2 38.30±1.09 b-d 58.53±2.12 i 72.73±2.7 h 78.67±0.7 i 116.29±3.5 g 117.07±4.26 f h0v3 37.24±1.06 c-e 73.90± 1.39 fg 101.01±6.26 d 126.87±2.7 c-f 129.58±2.7 de 134.2±2.37 de h0v4 39.16±1.12 bc 76.30±3.64 d-f 96.40±5.24 ef 118.93± 4.24 g 129.33±2.9 de 130.93±2.8 e h1v1 46.16±1.32 a 89.05± 4.16 a 109.97±4.05 ab 130.53±1.56 bc 156.30±5.19 a 157.23±5.76 b h1v2 33.33±0.95 fg 60.67± 2.75 i 78.30±2.79 g 79.27±0.89 i 120.54±3.87 fg 121.53± 5.4 f h1v3 39.59±1.13 bc 75.33± 2.27 e-g 109.23±7.66 ab 130.07±0.06 bc 131.42±3.03 c-e 133.50± 4.91 de h1v4 41.07±1.17 b 79.43±1.22 b-d 100.08±1.17 de 123.97±3.25 e-g 126.10±3.61 ef 130.40±3.64 e h2v1 44.50±1.27 a 89.83 ±3.33 a 111.83±5.93 a 130.56±1.91 bc 158.78±4.57 a 164.33±5 a h2v2 32.89±0.94 g 69.57±0.86 h 74.23±2.32 h 84.45±1.77 h 116.42±6.47 g 119.37±6.62 f h2v3 36.32±1.04 c-e 80.27±1.14 bc 106.27±6.65 bc 124.67±4.6 d-f 132.72 ±5.04 cd 133.70±5.87 de h2v4 35.65±1.02 d-g 77.40± 2.62 c-e 106.97±5.8 bc 129.31±1.46 b-d 136.43±4.1 c 137.83±4.1 d h3v1 46.17±1.32 a 89.37±2.93 a 109.62±6.96 ab 134.00±3.03 ab 158.37±0.87 a 161.81±1.92 ab h3v2 32.71±0.93 g 69.53±2.73 h 73.83±3.54 h 80.03±1.57 hi 117.79±0.51 g 121.47±1.03 f h3v3 33.97±0.97 e-g 82.50±0.75 b 104.36±4.05 c 136.07±0.37 a 133.80±0.46 cd 130.93±0.64 e h3v4 36.66±1.05 c-e 78.59±2.54 c-e 94.46 ±4.49 f 121.93±4.58 fg 132.07±0.57 cd 132.23±0.64 de se 1.59 1.60 1.83 2.45 2.82 3.16 cv(%) 5.04 2.54 2.32 2.59 2.58 2.85 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1; v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 chinigura variety had the tallest plants (46.2 cm) at 15 dat in pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots and statistically similar height was found in bispyribac sodium treated plots (46.2 cm), weedy check plots (45.6 cm), and acetochlor 14% + bensulfuron methyl 4% wp treated plots (44.5 cm) with the same variety. at 30, 45, 60 dat, and even at harvest, the tallest plants were found from chinigura variety in acetochlor 14% + bensulfuron methyl 4% wp treated plots and also from pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots and bispyribac-sodium wp treated plots. however, at 60 dat, brri dhan56 had the tallest plants in pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots and also from chinigura variety a a a a a a c c d c c c b b b a b b b b c b b b 0 50 100 150 200 15 dat 30 dat 45 dat 60 dat 90 dat at harvest p la n t h ei g h t (c m ) days after trasnplanting v1 v2 v3 v4 performance of herbicide mixture for t.aman rice 67 in the pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots. br11 recorded the shortest plants from pretilachlor 6% + pyrazosulfuron 0.15% wp treated plots at 15 dat. at 30, 45, 60, and 90 dat, and at harvest the shortest plants (58.5, 72.7, 78.7, 116.3 and 117.1 cm, respectively) were in the weedy check plots of chinigura variety. dry matter accumulation (dma), crop growth rate (cgr), and net assimilation rate (nar) application of herbicides significantly affected dma, cgr, and nar of t. aman rice at 30, 45, 60 and 90 dat (fig. 8). the maximum dmas (9.2, 27.5, 63.8 and 108.1 g plant−1 at 30, 45, 60 and 90 dat, respectively), cgr (3.94 mg cm-2 day-1), and nar (7.46 mg cm-2 day1) were recorded in acetochlor 14% + bensulfuron methyl 4% wp treated plots. the minimum dmas (5.7, 20.9, 49.5, and 90.3 g plant-1 at 30, 45, 60, and 90 dat respectively) and cgr (3.63 mg cm-2 day-1) were found in weedy check plots. the minimum nar (6.20 mg cm-2 day-1) was recorded in bispyribac-sodium wp treated plots. the dma and cgr differences in herbicidetreated plots over weedy check plots were due to the reduction of weeds which ultimately helped in undisturbed plant growth by utilizing its surrounded resources. similar result was also observed by lodhi (2016) who reported that weed control treatments caused remarkable variations in the quantity of dry matter accumulation and crop growth rate of rice. fig. 8. effect of herbicide(a) and variety (b) on dry matter accumulation plant-1 of t. aman rice at 30, 45, 60 and 90 days after transplanting here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha−1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1, v1 = chinigura, v2 = br 11, v3 = brri dhan56 and v4 = brri hybrid dhan6 the dry matter accumulation (dma) differs with the varieties due to the differences in leaf area, growth stage, and resources utilization ability of the varieties. in this study, varieties had significant effect on dmas of t. aman rice at 30, 45, 60 and 90 dat and also on cgr (fig. 8 and figure 9). br11 had the maximum dmas (8.32, 32.61, 74.26 and 125.85 g plant−1, respectively) at 30, 40, 60 and 90 dat and the maximum cgr (4.59 mg cm−2 day−1). while chinigura rice had the minimum dmas (7.18, 15.42, 39.27, and 72.95g plant−1 at 30, 40, 60 and 90 dat, respectively) and the minimum cgr (2.99 mg cm−2 day−1). usually, high yielding or hybrid varieties have competition, weed suppression, and resource utilization ability greater than the local varieties that influence dry matter accumulation. the results of this study are aligned with nahida et al. (2013), who reported that dry matter (dm) accumulation over time considerably varied with the varieties, and also with the study of mia and shamsuddin (2011), who reported that the higher cgr is related to higher leaf area index and net assimilation rate. the combined effect of herbicide and rice variety was significant on dma (table 8) and (table 9) cgr. the maximum dry matter accumulations (10.3, 37.5, 84.4, and 138.8 g plant-1, at 30, 45, 60, and 90 dat, respectively) and cgr (4.83 mg cm−2 day−1) were recorded in acetochlor 14% + bensulfuron methyl 4% wp treated plots of br11. in weedy check plots, d b b b c a a a a a a a b a a a 0 50 100 150 30 dat 45 dat 60 dat 90 dat d ry m a tt er a cc u m u la ti o n (g p la n t-1 ) h0 h1 h2 h3 b c c d a a a a b b b c a a a b 0 50 100 150 30 dat 45 dat 60 dat 90 dat v1 v2 v3 v4a b 68 jame et al. chinigura rice had the minimum cgr (2.76mg cm-2 day−1) and minimum dry matter accumulation at 30 dat (5.32 g plant−1). dmas at 45 and 60 dat were minimum (12.2 and 33.9 g plant−1) in bispyribacsodium treated plots of chinigura rice. table 8. combined effect of herbicide and rice variety on dry matter accumulation at 30, 45, 60, and 90 days after transplanting of t. aman rice treatment dry matter accumulation (g plant−1) 30 dat 45 dat 60 dat 90 dat h0v1 5.32±2.2 i 13.80±1.2 g 34.99±0.6 g 66.00±0.8 h h0v2 6.14±1.3 gh 26.11±0.4 e 60.05±1 d 108.07±1.2 f h0v3 5.58±0.5 hi 16.70±2.1 f 40.74±0.7 f 76.51±0.9 gh h0v4 5.58±4.8 hi 27.16±4.1 e 62.34±1.2 d 110.55±1.3 e h1v1 7.24±3.1 f 12.20±3.7 g 33.89±0.6 g 66.00±0.8 h h1v2 8.14±2.9 e 31.28±3.3 d 72.61±1.2 c 123.43±1.2 bd h1v3 6.71±3.9 fg 3237±4.3 cd 73.82±1.3 c 119.1±1.4 ce h1v4 8.29±5.1 d 32.88±1.9 cd 75.57±1.3 bc 114.69±1.5 de h2v1 8.91±1.3 cd 18.13±2.1 f 45.33±0.8 ef 80.78±0.9 g h2v2 10.26±1.9 a 37.45±1.4 a 84.40±1.4 a 138.76±1.5 a h2v3 8.27±2.2 d 18.72±1.7 f 46.23±0.8 e 82.57±0.9 g h2v4 9.48±1.4 bc 35.56±1.5 ab 79.28±1.3 ab 130.4±1.5 ab h3v1 7.24±1.8 f 17.55±2.4 f 42.93±0.7 ef 79.04±0.9 g h3v2 8.74±0.4 cd 35.58±0.8 ab 79.97±1.3 ab 133.1±1.5 ab h3v3 6.78±0.5 fg 18.58±2.5 f 45.19±0.8 ef 82.15±0.9 g h3v4 9.84±0.7 abg 34.24± 2.6 bc 76.5±1.3 bc 126.44±1.4 bc se 0.35 1.21 2.54 5.09 cv (%) 5.73 5.84 5.21 6.10 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha−1, h2 = acitachlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1; v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 table 9. combined effect of herbicide and rice variety on crop growth rate and net assimilation rate of t. aman rice treatments crop growth rate (mg cm−2 day−1) net assimilation rate (mg cm−2 day−1) h0v1 2.76±0.11g 6.04±0.4fg h0v2 4.27±0.17c 6.44±0.43de h0v3 3.18±0.13f 5.83± 0.39g h0v4 4.29±0.17c 7.19±0.48b h1v1 2.85±0.11g 6.15±0.41e-g h1v2 4.52±0.18b 6.25±0.42ef h1v3 4.03±0.16d 7.19±0.48b h1v4 3.48±0.14e 5.22±0.39h h2v1 3.15±0.13f 7.19±0.48b h2v2 4.83±0.19a 7.93±0.53a h2v3 3.23±0.13f 6.91±0.46bc h2v4 4.55±0.18b 7.82±0.52a h3v1 3.21±0.13f 7.76±0.52a h3v2 4.73±0.19a 6.74±0.45cd h3v3 3.29±0.13f 6.05±0.4fg h3v4 4.44±0.18b 6.96±0.46bc se 0.06 0.17 cv (%) 2.17 3.26 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acitachlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1; v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 performance of herbicide mixture for t.aman rice 69 a fig. 9. effect of herbicide (a) and variety (b) on crop growth rate of t. aman rice here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1, v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 b fig. 10. effect of herbicide (a) and variety (b) on net assimilation rate at 30, 45, 60, and 90 days after transplanting of t. aman rice in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha−1, h2 = acitachlor 14% + bensulfuron methyl 4% wp @ 750 g ha−1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha−1; v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 grain yield, straw yield, and harvest index the grain and straw yields (t ha-1) and harvest index (%) of t. aman rice were significantly influenced by herbicide application, and grain yield significantly varied with the herbicide treatments (figure 11, fig. 12 and figure 13). the grain and straw yields (3.25 t ha−1 and 2.26 t ha−1, respectively) and harvest index (36.0%) were the lowest in weedy check plots where weeds were allowed to grow throughout the crop growing season. the highest grain and straw yields (4.49 t ha−1 and 6.38 t ha−1, respectively) and harvest index (42.0%) were obtained from acetochlor 14% + bensulfuron methyl 4% wp, and it provided superior weed control over all other herbicide treatments. effective mix herbicides can affect a wide range of weed species causing a reduction of weed density comparable to single or other low-effective mix herbicide applications. the similar result reported by suryakala et al. (2019) showed that grain yield production was lower in un-weeded control, respectively indicating the importance of weed management in the critical growth period of the crop by herbicide application, which facilitated the efficient use of resources. hossain and mondal (2014) also reported that tank-mix application of bispyribac + ethoxysulfuron, pretilachlor fb metsulfuron-methyl + chlorimuron-ethyl and pretilachlor + bensulfuron resulted in more rice grain yield than their sole application. mishra (2019) reported c b a a 0 1 2 3 4 5 h0 h1 h2 h3 c ro p g ro w th ra te ( m g c m -2 d a y -1 ) d a c b 0 1 2 3 4 5 v1 v2 v3 v4 c d a b 0 2 4 6 8 10 h0 h1 h2 h3 n et a ss im il a ti o n r a te (m g c m -2 d a y -1 ) a a b a 0 2 4 6 8 v1 v2 v3 v4 n et a ss im il a ti o n r a te (m g c m -2 d a y -1 ) b a 70 jame et al. better performance of herbicide combinations in controlling weeds and increasing yield in transplanted rice. fig. 11. effects of herbicide and variety on grain yield of t. aman rice here, h0 = weedy check, h1 = bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1 v1 = chinigura, v2 = b 11, v3 = brri dhan56 and v4 = brri hybrid dhan6 grain and straw yields and harvest index were significantly varied with rice varieties (figure 11, figure 12, and figure 13). the maximum grain and straw yields (4.71 t ha-1 and 6.40 t ha-1, respectively) and harvest index (42.2%) were recorded from br11 because of producing the maximum number of filled grains per panicle along with a maximum 1000-seed weight that collectively contributed to higher grain yield. while chinigura rice had the minimum grain and straw yields (2.63 t ha-1 and 5.13 t ha-1, respectively) and harvest index (34.3%). the similar finding was reported by islam et al. (2013) that the varieties which produced a higher number of effective tillers hill–1 and a higher number of filled grains panicle–1 also showed higher grain yield ha–1. dutta (2002) also reported that the genotypes, which produced more effective tillers hill–1 and a higher number of grains per panicle also showed higher grain yield in rice. grain yield was significantly influenced by the combined effect of herbicide and rice variety (table 10). br11 had the maximum grain and straw yields (5.57 t ha−1 and 6.76 t ha−1, respectively) and harvest index (45.1%) in acetochlor 14% + bensulfuron methyl 4% wp applied plots while chinigura rice produced the minimum grain and straw yields (2.26 t ha−1 and 4.21 t ha−1, respectively) and harvest index (30.8%) in the weedy check plots. fig. 12. effect of herbicide and variety on straw yield of t. aman rice here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1 v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 d c a b 0 1 2 3 4 5 h0 h1 h2 h3 g ra in y ie ld ( t h a -1 ) c a b b 0 1 2 3 4 5 6 v1 v2 v3 v4 b b a b 0 2 4 6 8 h0 h1 h2 h3 s tr a w y ie ld ( t h a -1 ) c a b b 0 2 4 6 8 v1 v2 v3 v4 a b performance of herbicide mixture for t.aman rice 71 table 10. combined effect of herbicide and rice variety on grain and straw yields (t ha-1) and harvest index (%) of t. aman rice treatments grain yield (t ha−1) straw yield (t ha−1) harvest index (%) h0v1 2.26±0.41g 4.79±0.72e 32.00±0.86f h0v2 3.78±0.47e 5.94±0.74b-d 38.89±0.93de h0v3 3.26±0.41f 5.70±0.71cd 36.38±0.87e h0v4 3.68±0.46e 6.34±0.79a-c 36.73±0.87e h1v1 2.32±0.42g 4.21±0.74e 36.35±0.86e h1v2 4.55±0.57c 6.58±0.82ab 40.8 ±0.97b-d h1v3 3.98±0.5de 5.63±0.7d 41.42±0.97b-d h1v4 4.24±0.53cd 6.52±0.82ab 39.41±0.94 c-e h2v1 2.98±0.6f 6.71±0.86a 30.75±0.98f h2v2 5.57±0.7a 6.76±0.85a 45.09±1.07a h2v3 4.88±0.61b 6.34±0.79a-c 43.49±1.04ab h2v4 4.52±0.57c 5.72±0.72cd 44.14±1.05ab h3v1 2.94±0.49f 4.80±0.73e 37.98±0.96de h3v2 4.93±0.62b 6.32±0.79a-c 43.82±1.04ab h3v3 4.28±0.53cd 5.76±0.72cd 42.63±1.01 a-c h3v4 4.36±±0.54c 5.69±0.72cd 43.63±1.04ab se 0.11 0.31 0.45 cv (%) 4.84 6.61 5.31 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1. v1 = chinigura, v2 = br11, v3 = brri dhan56 and v4 = brri hybrid dhan6 economic viability of different treatments combination the economic performance of treatment combinations was determined ha-1 area basis, including total cost of production, gross returns, net returns, and benefit cost ratio (profit over per taka investment) under treatments imposed (table 11). cost of production varied due to different herbicide applications and rice variety cultivation. the cost of production varied mainly for the herbicide application. in the case of a weedy check, there was no involvement of cost for herbicide application. in this experiment, the highest total production cost occurred in pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1 mixed herbicide application along different rice variety cultivation and lowest in weed check fields along with different rice variety cultivation. gross return was influenced by different herbicide treatments along with different rice variety. the highest gross return (146010 taka) was recorded under acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 mixed herbicide along with br11 while the minimum (61290 taka) in weedy check plot along with chinigura. net return was varied by different herbicide treatments along with different rice variety. the highest net return (88699 taka) was recorded under acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 mixed herbicide along with br11 while the minimum (4849 taka) in bispyribac sodium wp @ 150 g ha-1 herbicide along with chinigura. benefit cost ratio (bcr) the benefit cost ratio varied in different herbicide treatments along with different rice variety. the highest benefit cost ratio (2.55) was recorded under acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 mixed herbicide along with br11 due to reason that higher grain yield (5.57 t ha-1), straw yield (6.76 t ha-1) and lower weed density (0.11) and weed biomass (0.33) per meter square were recorded under this treatment combination while the minimum (1.08) in bispyribac-sodium wp @ 150 g ha-1 herbicide along with chinigura. due to reason that effective 72 jame et al. mixed herbicide reduces wide density weed population while helping the plant to higher production due to fewer weeds competition. on the other hand, single herbicides reduce weed density of one or two species, which helps to grow others weeds, and they grow vigorously and consume more resources, resulting in poor crop plant growth. this result supports the findings of salam et al. (2020), who reported that benefit cost ratio varied among different rice varieties. sunil et al. (2010) also reported that pre-emergence application of bensulfuron methyl + pretilachlor (6.6 gr) @ 0.06 + 0.6 kg ha-1 + one inter cultivation at 40 das recorded significantly higher grain and straw yields (4425 and 5020 kg ha-1), lower weed population and dry weight (17 and 2.32 g m-2). this treatment also resulted in higher net returns and b:c ratio. table 11. cost of production, return and benefit cost ratio (bcr) of t. aman rice varieties i.e, chinigura, br11, brri dhan56 and brri hybrid dhan6 under different treatments treatment combinations fixed variable cost herbicide application cost total cost of production gross return (tk) net return (tk) bcr h0v1 55865 0 55865 61290 5425 1.10 h0v2 55865 0 55865 100440 44575 1.80 h0v3 55865 0 55865 87200 31335 1.56 h0v4 55865 0 55865 98340 42475 1.76 h1v1 56016 1345 57361 62210 4849 1.08 h1v2 56016 1345 57361 120330 62969 2.10 h1v3 56016 1345 57361 105130 47769 1.83 h1v4 56016 1345 57361 112520 55159 1.96 h2v1 56011 1300 57311 81210 23899 1.42 h2v2 56011 1300 57311 146010 88699 2.55 h2v3 56011 1300 57311 128340 71029 2.24 h2v4 56011 1300 57311 118720 61409 2.07 h3v1 56243 3364 59607 78300 18693 1.31 h3v2 56243 3364 59607 129570 69963 2.17 h3v3 56243 3364 59607 112760 53153 1.89 h3v4 56243 3364 59607 114690 55083 1.92 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significant ly at 0.05 level of probability. here, h0 = weedy check, h1= bispyribac sodium wp @ 150 g ha-1, h2 = acitachlor 14%+ bensulfuron methyl 4% wp @ 750 g ha-1 and h3 = pretilachlor 6% + pyrazosulfuron 0.15% wp @ 9.88 kg ha-1. v1 = chinigura, v2 = br 11, v3 = brri dhan56 and v4 = brri hybrid dhan6 conclusion the study suggests that the application of acetochlor 14% + bensulfuron methyl 4% wp @ 750 g ha-1 mixed herbicide combination with br11(mukta) gave the maximum grain and straw yields offering the highest gross return, net return, and benefit cost ratio. however, further investigation is necessary for the other soil types under different aezs in bangladesh. acknowledgement the authors acknowledged the farm division of sher-e-bangla agricultural university to provide the input materials and bangladesh rice research institute (brri) to supply the quality seeds that supported us a lot to conduct the study. references abbas, t., z.a. zahir, m. naveed and r.j. kremer. 2018. limitations of existing weed control practices necessitate development of alternative techniques based on biological approaches. adv. agron. 147: 239-280. performance of herbicide mixture for t.aman rice 73 afrin, n., s. bhuiya, r. uddin, s. bir and k. park. 2015. combined effect of herbicides on the weed management of rice. res. crops. 16(3): 416-421. ahmed, s., m. salim, and b.s. chauhan. 2014. effect of weed management and seed rate on crop growth under direct dry seeded rice systems in bangladesh. plos one. 9(7): e101919. alam, m.s., b.k. biswas, m.a. gaffer and m.k. hossain. 2012. efficiency of weeding at different stages of seedling emergence in direct-seeded aus rice. bangladesh j. sci. ind. res. 30(4): 155-167. bari, m.n., a.a. mamun and s.m.s. anwar. 1995. weed infestation in transplant aman rice as affected by land topography and time of transplanting. bangladesh j. agril. sci. 22(2): 227-235. bbs. 2019. yearbook of agricultural statistics of bangladesh 2019. bangladesh bureau of statistics, ministry of planning, government of the people’s republic of bangladesh. bcpa. 2020. registered pesticide list of bangladesh up to 2020. bangladesh crop protection association, farmgate, dhaka, bangladesh. beadle, c.l. 1985. plant growth analysis. in: techniques in bioproductivity analysis and photosynthesis, j. coombs, d.o. hall, s.p. long and j.m.o. scrulock (eds.). pergamon press. pp. 20-25. bharat, r. and d. kachroo. 2007. effect of different herbicides on mixed weed flora, yield and economics of wheat (triticum aestivum) under irrigated conditions of jammu. indian. j. agric. sci. 77(6): 383386. brri. 2008. annual report for 2008. bangladesh rice research institute, joydevpur, bangladesh. pp. 28– 35. chauhan, b.s. and d.e. johnson. 2011. row spacing and weed control timing affect yield of aerobic rice. field crops res.121(2): 226-231. das, t., m. banerjee, g.c. malik and b. mandal. 2017. efficacy of herbicides against weeds in transplanted wet season rice (oryza sativa l.). iosr. j. agric. vet. sci. 10(5): 1-3. dhawan, r.s., s. chawla, p. bhaskar, s.s. punia and r. angiras. 2009. effect of pinoxaden, an accase inhibitor on management of aryloxyphenoxypropionate resistant biotype of phalaris minor. in: abstracts national conference on frontiers in plant physiology towards sustainable agriculture. indian society of plant physiology. aau, jorhat. 5: 148. dutta, r.k., m.a. baset-mia and s. khanam. 2002. plant architecture and growth characteristics of fine grain and aromatic rices and their relation with grain yield. intl. rice comm. newsl. 51:51–56. gregory, f.g. 1926. the effect of climatic conditions on the growth of barley. ann. bot. 40: 1-26. hossain, a. and d.c. mondal. 2014. weed management by herbicide combinations in transplanted rice. indian j. weed sci. 46(3): 220–23. islam, n., m.y. kabir, s.k. adhikary and m.s. jahan. 2013. yield performance of six local aromatic rice cultivars. iosr. j. agric. vet. sci. 6(3): 58–62. lodhi, r. 2016. efficacy of bensulfuron methyl + pretilachlor against weeds in transplanted rice. m. s. thesis, department of agronomy, jawaharlal nehru krishi vishwa vidyalaya, jabalpur. magzter. 2021. business standard newspaper. september 16, 2020. pp. 1-2. mahbub, m.m. and. m.k.a bhuiyan. 2018. performance of bensulfuran methyl 12% + bispyribac sodium 18% wp against annual weeds in transplanted rice (oryza sativa l.) cultivation in bangladesh. sci. agric. 21(3): 85-92. mamun, a.a., s.m.r. karim, m. begum, m.i. uddin and m.a. rahman. 1993. weed survey in different crops under three agroecological zones of bangladesh. baures prog. 8: 41-51. mani v.s., m.l. malla, k.c. gautam and b. das. 1973. weed killing chemicals in potato cultivation. indian farming. 23(8): 17-18. mia, m.a.b. and z.h. shamsuddin. 2011. physio-morphological appraisal of aromatic fine rice (oryza sativa l.) in relation to yield potential. int. j. bot. 7: 223-229. mian, a.l. and m.s.u. bhuiya. 1977. cost, output and return in crop production. bangladesh j. agron. 1(1 & 2): 8. mishra, a. and g.c. tosh. 1979. chemical weed control studies on dwarf wheat. j. res. odisha uni. agric. technol. 10: 1-6. mishra, k. 2019. effect of herbicide bensulfuron methyl plus pretilachlor in weed management of transplanted kharif rice (oryza sativa l.). j. pharma. phytochem. 8(5): 378-382. mishra, r. 1968. community structure ecology work book. oxford ibh publ. co. new delhi. pp. 31-34. nahida, i., m.y. kabir, s.k. adhikary and m.s. jahan. 2013. yield performance of six local aromatic rice cultivars. iosr. j. agric. vet. sci. 6(3): 58-62. 74 jame et al. priya, h.r. and v.s. kubsad. 2013. integrated weed management in rainy season sorghum (sorghum bicolour). indian j. agron. 58(4): 548-553. rahman, m. 2016. herbicidal weed control: benefits and risks. adv. plants agric. res. 4(5): 371‒372. rahman, n.m.f., w.a. malik, m.s. kabir, m.a. baten, m.i. hossain, d.n.r. paul, r. ahmed, p.s. biswas, m.c. rahman, m.s. rahman, k.m. iftekharuddaula, s. hadasch, p. schmidt, m.r. islam, m.a. rahman, g.n. atlin and h.p. piepho. 2023. 50 years of rice breeding in bangladesh: genetic yield trends. theor. appl. genet. 136: 18. rajkhowa, d.j., n. borah, i.c. barua and n.c. deka. 2006. effect of pyrazosulfuron-ethyl on weeds and productivity of transplanted rice during rainy season. indian j. weed sci. 38: 25–28. ramana, a.v., d.s. reddy and k. ramakumar. 2014. influence of sowing time and nitrogen levels on growth, yield and n uptake of rainfed upland rice varieties. andhra. agric. j. 54(3 & 4): 114–120. rao, a.n., i.j. johnson, b. sivaprasad, j.k. ladha and a.m. mortimer. 2007. weed management in direct seeded rice. adv. agron. 93: 153–255. salam, m.a., s. sarker and a. sultana. 2020. effect of weed management on the growth and yield performances of boro rice cultivars. j. agric. food environ. 1(4): 1926. shew, a.m., a.d.m.b. putman, l.l. nalley and a. ghos. 2019. rice intensification in bangladesh improves economic and environmental welfare. environ. sci. policy. 95: 46-57. suryakala, p., g. murugan, m. saravanaperumal, k. suseendran and p. stalin. 2019. effect of weed management practices with new generation herbicides in transplanted rice. j. pharmacogn. phytochem. 8(3): 3913-3915. teja, k.c., b. duary, m. kumar and m.k. bhowmick. 2017. effect of bensulfuron methyl+pretilachlor and other herbicides on mixed weed flora of wet season transplanted rice. int. j. agric. environ. biotech. 8(2): 323-329. tshewang, s., m. brian, s.m. ghimiray and b.s. chauhan. 2016. weed management challenges in rice (oryza sativa l.) for food security in bhutan: a review. crop prot. 90: 117-124. watson, d.j. 1956. the dependence of net assimilation rate on leaf area index. ann. bot.18: 29-31. yadav d.b., s. singh, and a. yadav. 2008. evaluation of azimsulfuron and metsulfuron-methyl alone and in combination for weed control in transplanted `rice. indian j. weed sci. 40(1 & 2): 16-20. zahan, t., a. hashem, m.m. rahman, r.w. bell and m. begum. 2018. efficacy of herbicides in nonpuddled transplanted rice under conservation agriculture systems and their effect on establishment of the succeeding crops. acta sci. malays. 2(1): 17-25. zahan, t., m.f. hossain, a.k. chowdhury, m.o. ali, m.a. ali, e.s. dessoky, m.m. hassan, s. maitra and a. hossain. 2021. herbicide in weed management of wheat (triticum aestivum l.) and rainy season rice (oryza sativa l.) under conservation agricultural system. agronomy. 11(9): 1704. zahan, t., m.m. rahman, a. hashem and m. begum. 2017. response of transplanted aman rice varieties to herbicides in strip tilled non-puddled soil. fundum. appl. agric. 2(3): 303-310. blank page bangladesh agron. j. 2020, 23(2): 127-133 phosphorus and boron effects on nodulation and yield of soybean under non-saline agro-ecosystem of patuakhali s. shabnam 2 , s. ahmed 1 , s. mia 1 1 professor, department of agronomy, 2 ms student, department of agronomy patuakhali science and technology university corresponding e-mail: sultanpstu@yahoo.com received: 18 november, 2020, accepted: 23 december, 2020) keywords: soybean, nodule, phosphorus, boron, yield abstract the field experiment was conducted at agronomy field of patuakhali science and technology university, patuakhali during the period from december 2019 to may 2020 to evaluate the effect of phosphorus (p0 = 0 kg p ha -1 , p1 = 30 kg p ha -1 , p2 = 60 kg p ha -1 , p3 = 90 kg p ha -1 ) and boron (b0 = 0 kg b ha -1 , b1 = 4 kg b ha -1 , b2 = 6 kg b ha -1 ) and their combinations on nodulation and yield attributes of soybean. number of nodules plant -1 , number of pods plant -1 , number of seeds pod, 1000-seed weight, seed yield, stover yield, biological yield and harvest index increased significantly up to 60 kg p ha -1 . on the other hand, number of nodules plant -1 , number pods plants -1 , number of seeds pod -1 , 1000-seed weight, seed yield, stover yield, biological yield and harvest index of soybean were enhanced significantly up to 4 kg b ha -1 . the combination of 60 kg p ha -1 and 4 kg b ha -1 depicted the highest number of nodules (177.8), plant height (75.60 cm), number of pods plant -1 (92.72), number of seeds pod -1 (2.92), weight of 1000-seed (155.3 g) seed yield (1.91 t ha -1 ), stover yield (2.98 t ha -1 ), biological yield (4.89 t ha -1 ) and harvest index (39.06%). thus, the combined application of 60 kg p ha -1 and 4 kg b ha -1 could be the optimum for getting maximum yield of soybean. introduction soybean is the world’s leading economic oil seed crop. it has a great value as food, feed and fuel. it has a tremendous value in agriculture as a good source of high quality plant protein and vegetable oils and nitrogen fixing ability. soybean seed contains about 40-45% protein, 20-22% oil, 22-26% carbohydrate and a high amount of ca, p and vitamins a, b, c and d. it is used as raw materials in various industries viz. burnish, paint, soap, medicine and poultry feed (messina, 1997). the primary functions of phosphorus in plants are to store and transfer energy that is produced through the photosynthetic process to be used for growth and reproduction. phosphorus has a nutritional requirement of soybean for nodule development. it plays a key role in the energy metabolism of all plant cells, particularly in nitrogen fixation as an energy-requiring process (vadez et al., 1999). boron is essential for all plant growth. it aids in the transfer of sugars and nutrients from leaves to reproductive organ and increases pollination and seed development. soybean requires an equal supplier of available boron, especially during flowering and seed development. boron has several role in the soybean plant aiding cell formation, cell wall and vascular tissue formation, node number and plant height, flower development, pollen viability and ultimately pod formation and seed set. as boron is vital to flower formation and seed production, a decrease in boron supply during reproduction stage can result in decreased yield. boron deficiency results in interveinal chlorons of the plant foliage with 128 shabnam et al. brittle leaves in the youngest growth. a dead terminal growing point is one of the symptoms of boron deficiency in soybean. the southern part covers about 20% of the country which is equivalent to ~30% of the net cropped area. a large part of these cultivable lands remain fallow during rabi season, after harvesting t. aman. soybean as moderately salt tolerant crop could be grown economically in the coastal area of patuakhali (saic, 2007). many research works were done at home and abroad to specify the levels of phosphorus and boron application for ensuring maximum productivity of soybean. however, more researches are needed for prescribing the levels of both the nutrients in the coastal area of bangladesh. the present study was therefore undertaken to determine the optimum level of phosphorus and boron as well as their combinations for the maximum growth and yield performance of soybean at the coastal area. materials and methods the field experiment was conducted at agronomy field patuakhali science and technology university, dumki, patuakhali during the period december 2019 to may 2020. the pre-cropping soil of experimental field (0-15 cm depth) was determined as silty loam texture having ph – 6.6, organic matter – 1.10%, total nitrogen – 0.23%, p – 13.9 ppm, exchangeable k – 14.3 meq 100 g soil-1, s – 18 ppm and b – 59 ppm. the experiment was laid out in a factorial randomized complete block design with 3 replications. the variety bari soybean 6 was used as test crop. the unit plot size was 4 m  3 m, spacing 30 cm  10 cm. the experiment consisted two factors with four different levels of phosphorus such as p0: 0 kg p ha -1 , p1: 30 kg p ha -1 , p2: 60 kg p ha -1 , p3: 90 kg p ha -1 and 3 levels of boron such as b0: 0 kg b ha -1 , b1: 4 kg b ha -1 and b2: 6 kg b ha -1 . half of urea and entire amount of other fertilizers was applied as basal during final land preparation and remaining half of urea was applied as top dressed after 21 days and 55 days after sowing. the soil moisture was maintained around 60% field capacity by supplying irrigation water at different dates. different intercultural operations and plant protection measures were taken as and when necessary to raise healthy crop. the seeds of soybean were sown of 20 december 2019. the total number of nodules plant -1 was counted on five plants in different growth stages seedling, pre-flowering and flowering stage (i.e., 30, 60 and 90 days after sowing) to evaluate the nodulation pattern (mete, 2015). the counted nodule number -1 then averaged them to have the nodule number plant -1 . harvesting was done on 18 april 2020. data were collected an individual plant basis and seed yield plant -1 (g) was estimated after cleaning and proper drying. yield of individual plot excluding the broader plants was recorded and then converted to t ha -1 . plant performance was recorded taking measurements on plant height, number of pods plant -1 , number of seeds pod -1 , weight of 1000-seeds, seed yield, stover yield, biological yield and harvest index. the collected data on different parameters were analyzed using analysis of variance technique with the help of mstat-c computer program and the mean difference were compared by least significant test (lsd) at 5% level of significance. results and discussion plant height application of different levels of phosphorus and boron increased significantly the height of plant (table 1). there were significant variations among phosphorus, boron and their interactions. in case of phosphorus, the highest plant height (71.13 cm) was observed with 60 kg p ha -1 (p2) and the shortest (65.45 cm) in control (p0). in case of boron, the highest plant height (68.14 cm) was recorded with 4 kg b ha -1 (b1) and the shortest (65.86 cm) in b0 (table 2). in case interaction effect of phosphorus and boron, the highest plant height (75.60 cm) was found in p2b1 (table 3). further increase in the levels of p and b, decreased plant height. similar findings were also reported by singh et al. (1989). phosphorus and boron effects on nodulation and yield of soybean 129 table 1. effect of different levels phosphorus on plant height, number of nodules plant -1 and yield attributes of soybean phosphorus plant height (cm) number of nodules plant-1 number of pods plant-1 number of seeds pods-1 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) p0 65.45 b 100.4 d 69.97 c 2.44 c 140.8 c 1.26 d 2.38 d 3.64 c 34.62 c p1 65.98 b 125.4 c 76.97 b 2.54 ab 142.3 b 1.38 c 2.64 b 4.02 a 34.33 c p2 71.13 a 154.8 a 88.42 a 2.57 a 150.4 a 1.66 a 2.78 a 4.44 a 37.39 a p3 65.52 b 136.9 b 79.05 b 2.515 b 143.0 b 1.47 b 2.51 c 3.98 b 36.93 b cv (%) 3.87 4.05 6.11 5.57 3.05 4.50 2.82 2.97 2.52 figure followed by same letter (s) are statistically similar as per lsd at 5% p0: 0 kg p ha -1 , p1: 30 kg p ha -1 , p2: 60 kg p ha -1 , p3: 90 kg p ha -1 number of nodules plant -1 the nodule number plant -1 of soybean were found to increase significantly with increasing levels of phosphorus and boron application. the maximum number of nodules (154.8) plant -1 was recorded with 60 kg p ha -1 (p2) and the minimum (100.4) in control (p0) (table 1). the number of nodules plant -1 of soybean varied significantly also due to the different levels of boron application. among the boron treatments, 6 kg b ha -1 gave the maximum number of nodules (138.6) (table 2). table 2. effect of different levels of boron on plant height, number of nodules plant -1 and yield attributes of soybean boron plant height (cm) number of nodules plant-1 number of pods plant-1 number of seeds pods-1 1000 seed weight (g) seed yield (t ha-1) stover yield (t ha-1) biological yield (t ha-1) harvest index (%) b0 67.07 ab 113.1 c 79.74 a 2.42 b 142.6 b 1.29 c 2.37 c 3.66 c 35.25 b b1 68.14 a 136.5 b 79.8 2.54 a 145.3 a 1.59 a 2.71 a 4.30 a 36.97 a b2 65.86 b 138.6 a 76.99 b 2.57a 144.5 a 1.44 b 2.65 b 4.09 b 35.21 b cv (%) 3.87 5.57 6.11 4.05 3.05 4.50 2.82 2.97 2.52 figure followed by same letter (s) are statistically similar as per lsd at 5% b0: 0 kg b ha -1 , b1: 4 kg b ha -1 , b2: 6 kg b ha -1 in case interaction, the maximum number of (177.8) nodules plant -1 were found when crop was fertilized with 60 kg p ha -1 and 4 kg b ha -1 (table 3). these results showed that application of both p and b fertilizer individually increased nodulation with more response to p than b. in previous studies showed that both p and b have positive effect on nodulation and biological nitrogen fixation (hawkesford et al., 2011). when, p and b applied together, this effect augmented further suggesting an additive or synergistic effects. mia et al. (2013) reported that micronutrients specifically p and b has substantial role on nodulation and overall n fixation. therefore, our results corroborate the previous studies. number of pods plant -1 the highest number of pods plant -1 (88.42) was recorded with application of 60 kg p ha -1 which was significantly different from other treatments (table 1). the results are in agreement with the findings of khanam et al. (2016) who reported that the number of pods plant -1 increased with the increase of phosphorus rate up to a certain limit and then decreased. different levels of boron fertilizers also 130 shabnam et al. significantly influenced the number of pods plant -1 . the maximum number of pods plant -1 of soybean (79.8) was recorded from 4 kg b ha -1 (table 2). combined effect of p and b fertilizers application had significant effect on pods plant -1 of soybean. the highest number of pods (92.72) were recorded from 60 kg p ha -1 and 4 kg b ha -1 (table 3). positive influence of p and b application on number of pods plant -1 was also reported by sentimenla et al. (2012). table 3. interaction effect of phosphorus and boron on plant height, number of nodules plant -1 and yield attributes of soybean interaction plant height (cm) number of nodules plant-1 number of pods plant-1 number of seeds pods-1 1000 seed weight (g) seed yield (t ha-1) strover yield (t ha-1) biological yield (t ha-1) harvest index (%) p0b0 67.03 d 87.72 j 67.93 f 2.38 e 142.5 e 1.21 gh 2.23 f 3.44 f 35.17 e p0b1 63.55 h 99.43 i 73.03 e 2.38 e 139.3 fg 1.28 f 2.45 e 3.73 e 34.32 f p0b2 65.78 ef 114.0 h 68.95 f 2.54 cd 140.5 f 1.28 f 2.46 e 3.74 e 34.22 f p1b0 64.18 gh 115.3 h 76.30 d 2.49 d 146.0 d 1.24 g 2.48 e 3.71 e 33.42 g p1b1 68.22 c 128.0 f 77.55 d 2.37 e 138.3 g 1.49 d 2.71 bc 4.20 cd 35.48 e p1b2 65.55 ef 133.0 d 77.07 d 2.74 b 142.5 e 1.42 e 2.73 b 4.15 d 34.22 f p2b0 70.70 b 118.8 g 87.28 b 2.39e 145.5 d 1.53 c 2.63 d 4.16 d 36.78 c p2b1 75.60 a 177.8 a 92.72 a 2.92 a 155.3 a 1.91 a 2.98 a 4.89 a 39.06 a p2b2 67.10 d 168.0 b 85.25 c 2.41 e 150.5 b 1.53 c 2.73 b 4.25 c 36.00 d p3b0 66.38 de 130.8 e 87.45 b 2.4e 136.3 h 1.20 h 2.13 g 3.23 g 37.05.bc p3b1 65.18 fg 140.8 c 73.03 e 2.48 d 148.3 c 1.68 b 2.72 bc 4.40 b 38.18 b p3b2 65.00 fg 139.3 c 76.68 d 2.58 c 144.5 d 1.53 c 2.69 c 4.22 c 36.26 d cv (%) 3.87 5.57 6.11 4.05 3.05 4.50 2.82 2.97 2.52 figure followed by same letter (s) are statistically similar as per lsd at 5% level of significance number of seeds pod -1 number of seeds pod -1 of soybean showed significant variation due to different levels of phosphorus (table 1). the highest number of seeds pod -1 (2.57) was obtained when 60 kg p ha -1 was applied and it was minimum (2.44) in untreated plots (table 1). these results confirmed the findings of khanam et al. (2016) who reported that the number of seeds pod -1 increased with the increase of phosphorus rate up to a certain limit and then decreased. different levels of boron fertilizer also significantly influenced the number of seeds pod -1 (table 2). the maximum number of seeds pod -1 of soybean (2.57) was recorded from 4 kg b ha -1 . in case of interaction effect of phosphorus and boron fertilizers, the maximum number of seeds pod -1 (2.92) was found from 60 kg p ha -1 and 4 kg b ha -1 (table 3). weight of 1000seeds different levels of p had significant effect on 1000-seed weight of soybean (table 1). the heaviest 1000-seed (150.4 g) was recorded from 60 kg p ha -1 . the result was in agreement with those of devi et al. (2012) who observed a significant variation in 1000-seed weight due to boron levels. the application of 4 kg b ha -1 resulted in maximum 1000-seed weight (145.3 g) (table 2). although, the seed weight has been a quite static yield parameter, the combination of p and b had significant effect on 1000-seed weight of soybean (begum et al. 2015, sentimenla et al. (2012)). this results that the soil in the experimental sites is largely deficient of p and b. seed yield the highest soybean yield (1.66 t ha -1 ) was produced when the crop was fertilized with 60 kg p ha -1 and the lowest (1.26 t ha -1 ) in control treatment (table 1). the result was supported by the findings of phosphorus and boron effects on nodulation and yield of soybean 131 khanam et al. (2016). seed yield of soybean varied significantly with different levels of b fertilizer application (table 2). the maximum yield of soybean (1.59 t ha -1 ) was recorded from 4 kg b ha -1 and the lowest (1.29 t ha -1 ) from control treatment (table 2). the results were in agreement with those of sentimenla et al. (2012) who observed that application of 1.5 kg b ha -1 increased soybean seed yield. they also reported that b is vital to flower formation and seed production. the highest seed yield (1.91 t ha -1 ) was recorded with the combination of 60 kg p ha -1 and 4 kg b ha -1 (table 3). the increased yield in this treatment was occurred possibly due to higher number of pods plant -1 and seeds pod -1 with a heavier individual seed weight. stover yield stover yield of soybean varied significantly with different levels of p and b application. the highest stover yield (2.78 t ha -1 ) was obtained when the crop was fertilized with 60 kg p ha -1 and the lowest (2.38 t ha -1 ) in control plot (table 1). the maximum stover yield (2.71 t ha -1 ) was recorded from 4 kg b ha -1 (table 2). different levels of p and b fertilizers in combination affected significantly the stover yield of soybean. the highest stover yield (2.98 t ha -1 ) was harvested with the combined application of p and b @ 60 kg and 4 kg ha -1 respectively (table 3). biological yield biological yield of soybean showed significant variation due to different levels of phosphorus (table 1). the maximum biological yield (4.44 t ha -1 ) was recorded from 60 kg p ha -1 while, the maximum biological yield (4.30 t ha -1 ) was recorded in 4 kg b ha -1 (table 2). the highest biological yield (4.89 t ha -1 ) was recorded from the combination of 60 kg p ha -1 and 4 kg b ha -1 (table 3). generally biological yield increased with the increasing doses of p and b fertilizer application along with other recommended applied fertilizer. since p and b has significant positive impact on biological nitrogen fixation, the plant might have had harvested more n through biological nitrogen fixation. in addition, nutrients maintain stoichiometry in building cells and organs and therefore, application of a deficient nutrient (as p and b in our case) could have improved uptake and assimilation of other nutrients resulting a significant improvement of yield (hawkesford et al., 2011; khanam et al., 2016; sentimenla et al., 2012). harvest index harvest index of soybean varied significantly with different levels of phosphorus and boron application. the maximum h1 (37.39%) was recorded from 60 kg p ha -1 (table 1). the result was consistent with the findings of malik et al. (2006) who found that h1 varied significantly due to different levels of phosphorus. the maximum h1 of soybean (36.97%) was recorded from 4 kg b ha -1 (table 2). combined effect of phosphorus and boron had also significant effect on harvest index of soybean. the highest (39.06%) was recorded from the combination of 60 kg p ha -1 and 4 kg b ha -1 (table 3). conclusion the present study revealed that the application of p and b fertilizers influenced nodule formation, yield attributes and seed yield of soybean. the application of 60 kg p ha -1 and 4 kg b ha -1 could be the most suitable levels for maximum productivity of soybean under non-saline agro-ecosystem of patuakhali. acknowledgement the authors avail the opportunity to express their sincere thanks and heartfelt gratitude to bangladesh university grants commission for financial support and cooperation for conducting field experiment 132 shabnam et al. and preparation of the thesis for awarding ms degree in agronomy, patuakhali science and technology university. references begum, a., m.a. islam, q.m. ahmed, m.a. islam and m.m. rahman. 2015. efffect of nitrogen and phosphorus on the growth and yield performance of soybean. res. agric. livest. fish. 2(1): 35-42. devi, k.n., l.n.k. singh, t.s. devi, h.n. devi, t.b. singh, k.k. singh and w.m. singh. 2012. response of soybean [glycine max (l.) merrill] to sources and levels of phosphorus. j. agril. sci. 4(6): 4453. hawkesford, m., w. horst, t. kichey, h. lambers, and j. schjoerring. 2011. functions of macronutrients. in: marschner, p. (ed.), marschner’s mineral nutrition of higher plants: third edition. academic press, london, uk, pp.191-248. khanam, m.s. islam., m.h. ali, i.f. chowdhury and s.m. masum. 2016. performance of soybean under different levels of phosphorus and potassium. bangladesh agron. j. 19(1): 99-108. malik, m.a., m.a. cheema, h.z. khan and m.a. wahid. 2006. growth and yield response of soybean (glycine max l.) to seed inoculation and varying phosphorus levels. j. agric. res. 44(1): 47-53. messina, m. 1997. soyfoods: their role in disease prevention and treatment, in: liu, k (ed.) soybeans: chemistry, technology and utilizations, chapman and hill, new york pp. 442-466. mete, f.z., s. mia, f.a. dijkstra, m. abuyusuf and a.s.m.i. hossain. 2015. synergistic effects of biochar and npk fertilizer on soybean yield in an alkaline soil. pedosphere, 25: 713-719. mia, s., j.w. van groenigen, t.f.j. van de voorde, n.j. oram and t.m. bezemer. 2014. biochar application rate affects biological nitrogen fixation in red clover conditional on potassium availability. agric. ecosys. environ. 191: 83–91. saic. 2007. saarc agricultural statistics of 2006-07. saarc agricultural information center, farmgate, dhaka-1215, bangladesh. p.23. sentimenla, a., k. singh and s. singh. 2012. response of soybean to phosphorus and boron fertilization in acidic upland soil of nagaland. j. indian soc. soil sci. 60(2): 01-04. singh, b.p., b. singh and b.n. singh. 1989. influence of phosphorus and boron on picking behaviour and quality of french bean (phaseolus vulgaris) under limited irrigation, grown in alfisols deficient in phosphorus and boron. indian j. agril. sci. 59: 541-543. vadez, v., j.h. lasso., d.p. beck and j.j. drevon. 1999. variability of nitrogen fixation in common bean (phaseolus vulgaris l.) under phosphorus deficiency in related to phosphorus use efficiency. euphytica 106: 231-242. bangladesh agron. j. 2020, 23(2): 87-95 on-farm adaptation of some oilseed crops under acidic soil of sylhet region in bangladesh *m. i. nazrul 1 and m. akkas ali 2 1 pso, 2 cso & head, ofrd, bari, bangladesh *corresponding email: mi_nazrul@yahoo.com (received: 13 october, 2020, accepted: 26 october, 2020) key words: oilseed crops, adaptation, crop productivity, acidic soil abstract screening of improve varieties for new areas is necessary to address the soil and environment for improving crop production systems. in this context, six separate field trials were conducted at farmer’s field in sylhet areas for the two consecutive crop seasons during 2017-18 and 2018-19, respectively to evaluate the performance of improved varieties of crops with the existing cultivars. each experiment was laid out in randomized complete block design with six dispersed replications. the unit plot size was varied with experiments. the result showed that improved varieties of oilseed crops mustard var. bari sarisha-16, soybean var. bari soybean-6, groundnut var. bari chinabadam-9, sesame var. bari til-4 and sunflower var. bari surjomukhi-2 performed better under the soil and climatic conditions of sylhet region. this result reveled that these varieties of oilseed crops could be suitable for higher productivity and economic return. introduction bangladesh is one of the most important agrarian’s countries in the world; agriculture sector is the country’s main source of food security, employment, and poverty alleviation. more than 70 percent of bangladesh’s population and 77 percent of its workforce lives in rural areas. nearly half of all of bangladesh’s workers and two-thirds in rural areas are directly employed by agriculture, and about 87 percent of rural households rely on agriculture for at least part of their income (world bank group, 2019; rahman and schmitz, 2007). the sylhet regions are mostly under the agroecological zone -20 (eastern surma kushiyara floodplain), and the soils of this region are strongly acidic (ph 4.5-5.5). farmers mainly grow rice under rain fed ecosystem. the climate of this region is suitable for potato, tomato, cabbage, aroids, wheat and different pulse and oilseed crops (nazrul, 2017; nazrul and shaheb, 2014; nazrul et al., 2013; shaheb et al., 2012; sarker, et al., 2012; nazrul and shaheb, 2012; rahman et al., 2013) in rabi and kharif seasons, respectively. generally, farmers in this region cultivate different crops of local varieties in both seasons under poor management practices. as a result, much lower yield is achieved in sylhet areas (nazrul et al., 2017; nazrul et al., 2013). so, introduction of new crops with modern varieties along with appropriate agronomic management practices would boost up the farm productivity that will reduce the poverty level of resource poor farmers of that area. in addition, agriculture is the only economic activity of most small farmers in this region. about 40-45 % lands of total cultivable area remain fallow due to lack of irrigation and not available suitable different crop varieties under present prevailing agro-climatic situation. nazrul et al. (2020) reported that some crop varieties of pulse, tuber and spices performed better under the soil and climatic conditions of sylhet region. information related to varietal adaptability of different oilseed crops like mustard, soybean, groundnut, sesame, linseed and sunflower in the study areas of rice based rainfed eco-system under climate change situation is scanty. hence, an 88 nazrul et al. experiment was undertaken with an objective to evaluate the yield performance of improved varieties of oil seeds crops with the existing cultivars at farmers' field of sylhet region. materials and methods a total of six separate trials were conducted at farmer’s field in sylhet area for two consecutive crop seasons during 2017-18 and 2018-19 to evaluate the performance of improved crop varieties with the existing cultivars cultivated by the farmers. the study areas are located at latitude 24° 29' n and longitude 91° 39' e of bangladesh. the soil of experimental plots was non-calcareous gray with low organic matter content (1.23%), low soil ph (4.5-5.4), very low total n (0.06%), low content of p (9.46 µg/g), k (0.14) and s (10.07) whereas zn (1.13) and boron (0.51) medium and optimum, respectively. each experiment was laid out in randomized complete block design with six dispersed replications. the unit plot size was varied with the experiments. the monthly air temperature and rainfall during the study period are presented in figure 1. the monthly mean minimum and maximum temperature was 9.53 0 c and 36.43 0 c during the crop season, respectively. during experimentations a total of 7684 mm precipitation was occurred in this region; whereas lowest rainfall 10.9 mm and highest 2465 mm was occurred in january and june, respectively. fig. 1. average of two years monthly maximum and minimum air temperatures ( 0 c) and total rainfall (mm) during study period (source: meteorological department, sylhet) mustard the on-farm trial was conducted at farming system research and development (fsrd) site, kamalbazar, south surma, sylhet. six mustard varieties viz. bari sarisha-9, bari sarisha-11, bari sarisha-13, bari sarisha-14, bari sarisha-15 and bari sarisha-16 were used in this field trial. the crop was fertilized with 90-27-32-10-1.0-0.5 kgha -1 of npksznb (frg, 2012). half of nitrogen and all amounts of phosphorous, potassium, sulpher, zinc and boron were applied during final land preparation. the remaining half nitrogen was applied as top dress at the time of flower initiation. the experiment was conducted under rainfed condition. the seeds were sown on 20-25 november in broadcast method in both years maintaining the seed rate of 7-8 kg ha -1 . the unit plot size was 12 m20 m. the crop was harvested on18-25 february in both years. pesticides rovral 50 wp 0.2 % for controlling gray blight and nitro 505 ec @ 0.5 ml l -1 of water was used against mustard aphid. 0 5 10 15 20 25 30 35 40 0 500 1000 1500 2000 2500 3000 jan. feb. mar. apr. may jun. nov. dec. total rainfall (mm) maximum tem. (0c) minimum tem. (0c) r ai n fa ll ( m m ) t em p er at u re ( o c ) months on-farm adaptation of some oilseed crops under acidic soil of sylhet 89 soybean the experimentation was conducted at farmer’s field under farming system research and development (fsrd) site, kamalbazar, south surma, sylhet. three soybean varieties viz. bari soybean-5, bari soybean-6 and shohag were used in this experiment. cop was fertilized with 23-30-50-15-1.0 kg ha -1 of npksb (frg, 2012). all fertilizer nutrients were applied during final land preparation. seeds of soybean were sown on 15-18 december in broadcast method in both years with maintained the seed rate of 80-90 kg ha -1 . the unit plot size was 8 m5 m. the crop was harvested at full maturity on 5-10 april in both years. there was no remarkable disease and pest attack, except white fly and it was successfully controlled by applying nitro 505 ec at the rate of 0.5 ml l -1 . groundnut the experiment was conducted at farmer’s field under multilocation testing (mlt) site, sunamganj. the experimental material comprised of two varieties viz. bari chinabadam-8 and bari chinabadam-9 including local were used in this experiment. the seeds of groundnut were sown on 2-5 november in both years with maintaining the spacing of 40 cm15 cm. the unit plot size was 8 m5 m; where total of 650 plants were accommodated and harvested on 5-7 march in both years with maintaining 90-100 kg seeds ha -1 . before sowing, seeds were treated with provex @ 0.2% to prevent seed and soil borne diseases. weeding followed by irrigations were done twice at 15-20 and 45-50 days after sowing of seed and earthing up was followed as per package of practices of groundnut (pradheeban et al., 2016).the crop was fertilized with 25-160-85-300-10 kg urea-tsp-mop-gypsumboric acid ha -1 . the half urea and entire amount of tsp, mp, gypsum and boric acid were applied during final land preparation. the rest half urea was top dressed at the initial stage of peg developments. sesame the on-farm trial was conducted at upper-part of hakaluki haor, beanibazar area under sylhet. four sesame varieties viz. bari til-2, bari til-3, bari til-4 and t-6 was used in this trial. the unit plot size was 10 m x 10 m. seeds were sown in broadcast method. the fertilizer nutrients npksznb @ 6030-40-18-2-0.5 were applied in the form of urea, tsp, mop, sulpher, gypsum and boron, respectively as per frg 2012. full dose of all fertilizers and half of urea were applied at the time of final land preparation. remaining nitrogen was applied as top dress at 25-30 days after sowing. the trial was conducted under rainfed condition. sesame seeds (7-8 kg ha -1 ) were sown on 15-18 march in both years. the crop was harvested at full maturity on 12-15 june in both years. intercultural operations viz. weeding and thinning were done in order to support normal plant growth. linseed the experiment was conducted at farmer’s field under multilocation testing (mlt) site, zokiganj. four different cultivars of linseed viz. bari tisi-1 (nila), noakhali local, patuakhali local and zokiganj local were tested in this field trial. the crop was fertilized with 31-13-20-8 kg ha -1 of npks (frg, 2012). half of nitrogen and all phosphorous, potassium and sulpher were applied during final land preparation. the remaining nitrogen was applied at the time of flower initiation as top dress. the seeds (7-8 kg ha -1 ) were sown on 20-25 november in both years in broadcast method. the unit plot size was 10 m8 m. once weeding followed by irrigation was provided at 30-35 days after sowing. the crop was harvested at maturity on 13-15 march in both years. the fungicide bavistin 70 wp (0.2 %) was applied for controlling foot rot disease and in order to support normal growth of linseed. 90 nazrul et al. sunflower the field trial was conducted at farming system research and development (fsrd) site, kamalbazar, south surma, sylhet. three sunflower varieties viz. bari surjomukhi-2, bari surjomukhi-3 and hysun-33 were used in this experiment. the crop was fertilized with 90-35-75-25-1.0-0.5 kg ha -1 of npksznb (frg, 2012). half of nitrogen and all phosphorous, potassium, sulpher, zinc and boron were applied during final land preparation. the remaining nitrogen was applied as top dress in two equal splits at 20-25 and 40-45 days after sowing (das). the seeds (10-12 kg ha -1 ) were sown on 1520 november in both years maintaining the spacing of 50 cm30 cm. the unit plot size was 8 m5 m. the crop was harvested on 25-28 february in both years. seeds were treated with provex-200 @ 3g kg 1 before sowing. twice irrigations were done at 30 and 50 days after sowing of seed. the yield data was recorded from whole plot basis. yield and yield contributing characters were analyzed statistically using “star” software package and means were separated by lsd test at 0.05 % level of significance. results and discussion mustard seed yield and yield components of mustard varieties are presented in table 1. number of days required from sowing to harvesting (76-103 days) of mustard varieties differed significantly. the duration of bari sarisha-16 was the maximum (103 days) which was at par with bari sarisha-13 (100 days) and bari sarisha-11 (98 days). on the contrary, duration of bari sarisha-14 (84 days) and bari sarisha-15 (88 days) was identical but 19 days shorter than bari sarisha-16.the maximum plant height (126.30 cm) was recorded in bari sarisha-16 which was closely followed by bari sarisha-11 and lowest plant height (80.00 cm) was measured in bari sarisha-9.on the other hand, number of siliquaplant -1 was significantly different among the varieties (table 1). the highest number of siliquae plant -1 was recorded in bari sarisha-11 (164) which was identical with bari sarisha-16 (154). inversely, bari sarisha-13 (68) and bari sarisha-15 (66) produced statistically similar number of siliquaplant -1 but much lower than bari sarisha-16 (154). the lowest number of siliqua plant -1 was observed in bari sarisha-9 (53). the results were in agreement with the findings of islam et al. (2015). number of seeds siliqua -1 is a genetically controlled trait differed significantly in mustard varieties. bari sarisha-14 had the highest number of seeds siliqua -1 (26.67). bari sarisha-11 (11.38) and bari sarisha-16 (12.67) produced statistically identical number of seeds siliqua -1 . the seed size i.e. 1000-seed weight of bari sarisha-11 (3.1 g), bari sarisha-13 (3.4 g) and bari sarisha-14 (3.7 g) was identical. bari sarisha-16 produced the smaller sized seeds (2.4g) which was statistically similar with bari sarisha-9 (2.5 g). yield is directly proportional to the cumulative effect of yield attributes. the highest seed yield was recorded in bari sarisha-16 (1230kgha -1 ) which was at par with bari sarisha-11 (1140kgha -1 ). the higher seed yields in the afore said varieties were occurred due to higher number of siliqua plant -1 though much lower in seedssiliqua -1 and also seed size. mian and islam (2010) also reported higher seed yield due to higher siliqua plant -1 . on the contrary, as a short duration varieties, bari sarisha-14 and bari sarisha-15 produced significantly lower seed yields of 890 and 980 kg ha -1 , respectively compared to long duration varieties (100-103days). the results revealed that long duration var. bari sarisha-11 and bari sarisha-16 could be grown in fallow land areas for higher yield but if other crops grown in kharif-i then short duration mustard variety bari sarisha-14 and bari sarisha-15 could be grown. on-farm adaptation of some oilseed crops under acidic soil of sylhet 91 table 1. days to maturity, plant height, seed yield and yield contributing characters of mustard varieties at rainfed eco-system (pooled) name of variety days to maturity plant height (cm) siliqua plant-1 seeds siliqua-1 1000-seed weight (g) seed yield (kg ha-1) bari sarisha-9 76 80.00 53 13.33 2.5 680 bari sarisha-11 98 105.00 160 11.38 3.1 1140 bari sarisha-13 100 100.70 68 22.33 3.4 970 bari sarisha-14 84 85.00 55 26.67 3.7 780 bari sarisha-15 88 87.00 66 22.67 3.2 780 bari sarisha-16 103 126.30 154 12.67 2.4 1230 lsd(0.05) 5.54 14.69 5.3 5.29 0.2 0.18 cv (%) 3.30 8.44 7.5 16.10 5.1 10.95 soybean plant height, number of pods plant -1 , seeds pod -1 , 100-seed weight and seed yield of soybean varieties are presented in table 2. the tallest plant (54.80 cm) was obtained by bari soybean-6. pods plant -1 and seeds pod -1 of different soybean varieties did not differ significantly due to uniformity of pods plant -1 and seeds pod -1 . bari soybean-6 produced numerically maximum number of pods, as a result, the highest number of pods plant (31.10) was recorded in this variety and it was statistically identical with others. higher number of seeds pod -1 was also observed in bari soybean-6. the weight of 100seed of soybean varieties varied significantly in rain fed eco-system under climate change situation. hundred seeds weight followed a similar trend to seeds pod -1 . the highest weight (12.41 g) of 100-seed was recorded in bari soybean-6. seed yield was not varied significantly but numerically bari soybean-6 produced higher seed yield (1365 kg ha -1 ) while sohag was the lowest yielder (1184 kg ha 1 ). yield variation in different soybean varieties was attributed to the cumulative effects of different yield components. similar finding was also reported by islam et al. (2015) and islam and biswas (2010). table 2. yield contributing characters and yield of soybean varieties at farmer’s field of sylhet (pooled ) variety plant height (cm) pods plant-1 seeds pod-1 100-seed weight (g) days to maturity seed yield (kg ha-1) bari soybean-5 51.90 30.76 2.45 10.83 112 1285 bari soybean-6 54.80 31.10 2.60 12.41 113 1365 sohag 50.58 29.70 2.30 10.10 112 1184 lsd(0.05%) 2.36 ns ns 1.96 ns ns cv (%) 2.60 7.48 6.80 10.07 6.24 7.93 groundnut the maximum days to maturity was recorded in bari chinabadam-9 followed by bari chinabadam8 (table 3). the maximum number of pods plant -1 (16.87) was recorded in bari chinabadam-9 followed by bari chinabadam-8, while the lowest in local cultivar (14.83). the highest 100-kernel weight (39.65 g) was recorded in bari chinabadam-9 and the lowest (33.92 g) was in local. higher kernel yield contributed to greater shelling percent and provide higher nut yield. the maximum shelling percent (76.64%) of groundnut was recorded in bari chinabadam-9 followed by bari chnabadam-8 and local. the yield did not varied significantly but numerically higher nut yield (1.57 t ha -1 ) was recorded in bari chinabadam-9 followed by bari chinabadam-8 (1.40 t ha -1 ) and the lowest in local (1.25 t ha -1 ). among the yield components, number of pods plant -1 and kernel weight were more closely associated with pod yield ha -1 . 92 nazrul et al. table 3. days to maturity, yield contributing characters and nut yield of different groundnut varieties at farmer’sfield in sylhet region (pooled). variety days to maturity pods plant-1 (no.) 100-kemel wt. (g) shelling (%) nut yield (t ha-1) bari chinbadam-8 139 15.67 34.81 73.14 1.40 bari chinbadam-9 142 16.87 39.65 76.64 1.57 local 137 14.83 33.92 69.78 1.25 lsd(0.05) ns ns ns ns ns cv (%) 1.37 9.55 7.60 3.43 13.28 sesame results indicated that the maximum plant height (101.10 cm) was found in the variety bari til-4 that was followed by t-6 and bari til-2 (99.89 cm). the maximum number of pods plant -1 was recorded in var. bari til-2 (71.33) that was followed by t-6 and bari til-4. higher number of seeds pod -1 was found in var.t-6 (70.33) followed by bari til-2 (67.33) and the lowest seeds pod -1 in bari til-3 (53.00). the maximum pod length (2.90 cm) was found in t-6 followed by bari til-2. the maximum seed yield was recorded in bari til-4 (1.15 t ha -1 ) that was statistically similar to that of bari til-2 (1.14 t ha -1 ), whereas lowest seed yield was produced by the variety bari til-3 (0.84 t ha -1 ). table 4. seed yield and yield contributing characters of sesame varieties at farmer’s field of sylhet (pooled) variety plant height (cm) plant m-2 (nos.) pods plant-1 (nos.) seeds pod-1 (nos.) pod length (cm) seed yield (t ha-1) bari til-2 99.89 37.23 71.33 67.33 2.67 1.14 bari til-3 95.76 44.57 50.33 53.00 2.37 0.84 bari til-4 101.10 40.57 65.33 61.33 2.60 1.15 t-6 (control) 99.83 41.23 68.67 70.33 2.90 0.98 lsd(0.05) 2.57 ns 10.21 11.69 0.19 0.18 cv (%) 1.25 9.61 8.33 8.92 1.84 8.14 linseed the highest plant height was obtained in bari tisi-1 (64.85 cm) while the shortest plant in noakhalilocal (52.73 cm). the highest number of pods plant -1 was recorded in zakigonj-local (31.40). but plants m -2 and seeds pod -1 was non-significant (table 5). among the varieties, zakigonj-local produced highest 1000 seeds weight (4.01 g) that was followed by noakhali local (3.66 g) and the lowest 1000 seeds weight in bari tisi-1 (3.57 g). likewise, the highest seed yield (0.94 t ha -1 ) of linseed was recorded in zakigonj-local that was statistically followed by noakhali-local (0.81 t ha -1 ). however, the lowest seed yield (0.74 t ha -1 ) was found in patuakhali-local. table 5. seed yield and yield contributing characters of linseed at farmer’s field of sylhet region (pooled) variety plant height (cm) pods plant-1 (nos.) plants m-2 (cm) seeds pod-1 (nos.) 1000seed weight (g) seed yield (t ha-1) nila (bari tisi-1) 64.85 21.28 221 7.22 3.57 0.76 noakhali-local 49.55 20.63 191 7.37 3.66 0.81 patuakhali-local 52.73 19.13 207 7.53 3.64 0.74 zakigonj-local 50.80 31.40 201 7.73 4.01 0.94 lsd (0.05) 4.17 9.6 ns ns 0.6 0.27 cv (%) 3.69 20.55 8.21 7.53 4.74 5.93 on-farm adaptation of some oilseed crops under acidic soil of sylhet 93 sunflower the var. bari surjomukhi-2 produced the maximum (167.77 cm) plant height, which was lowest value (91.02 cm) produced by bari surjomukhi-3 at physiological maturity (table 6). the plant heights of sunflower var. bari surjomukhi-2 was uneven but means height was statistically than others. the differences in plant height may be attributed to the genetic potential of variety and the other prevailing environmental conditions. the plant height of some sunflower hybrids increased with increasing temperature. similar results were reported by anderson et al. (1978); qadir (2006) and canava et al. (2010).the maximum days to maturity (126) were recorded in hybrid hysun-33 and minimum days to maturity were observed in bari surjomukhi-3 (102). total seeds head -1 (903.15) was highest in bari surjomukhi-2 and that of minimum (757.48) was produced in bari sunflower-2. this may be due to comparatively large head size and small seed size. similar trend was also found in case of seed weight head -1 . maximum seed weight (51.42 g) head -1 as obtained from bari surjomukhi-2 followed by hybrid hysun-33 and bari surjomukhi-3. the 1000seed of the sunflower cultivars ranged from 61.38 to 95.00 g. the sunflower var. bari surjomukhi-2 produced the maximum 1000-seed weight (95.00 g), which was significantly different from the other values of this trait. bari surjomukhi-3 produced the minimum 1000-seed weight (61.38 g) in table 4. similar 1000-seed weight was reported by hossain et al. (2018). the seed yield of tested sunflower varieties did not differ significantly. the seed yield plant -1 of all the sunflower cultivars ranged from 1783 to 2033 kg ha -1 . though seed yield was not significant but maximum seed yield (2033 kg ha -1 ) was observed in bari surjomukhi-2.the lowest seed yield (1783 kg ha -1 ) was found in the bari surjomukhi-3. table 6. seed yield and yield contributing characters of sunflower varieties at farmer’s field of sylhet region (pooled) variety plant height (cm) days to maturity total seed head-1 seed weight head-1 (g) 1000seed weight (g) seed yield (kg ha-1) bari surjomukhi-2 167.77 105 903.15 51.42 61.38 2033 bari surjomukhi-3 91.02 102 757.48 42.79 65.00 1783 hysun-33 138.00 126 793.87 43.14 95.00 1800 lsd(0.05%) 6.65 2.77 2.78 2.77 2.78 ns cv (%) 3.25 5.37 2.57 2.60 5.53 11.37 conclusion it showed from the results that mustard var. bari sarisha-16, soybean var. bari soybean-6; groundnut var. bari chinabadam-9; sesame var. bari til-4 and sunflower var. bari surjomukhi-3 could be grown in sylhet region under aez 20 for higher productivity and economic return. acknowledgement authors are gratefully acknowledged bangladesh agricultural research institute, gazipur and meteorological department, sylhet for providing financial help and logistic support and weather data, respectively. thanks to others who contributed in editing and compiling the manuscript. 94 nazrul et al. references anderson, w.k., r.c.g. smith and j.r. mc william. 1978. a systems approach to the adaptation of sunflower to new environments i. phenology and development. field crops res. 1: 141-152. canavar, ö., f. ellmer and f.m. chmielewski. 2010. investigation of yield and yield components of sunflower (helianthus annuus l.) cultivars in the ecological conditions of berlin (germany). helia, 33, nr. 53, pp.117-130. gulles, a.a., v.i. bartolome, r.i.z.a. morantte, l.a. nora, c.e.n. relente, d.t. talay and g. ye. 2014. randomization and analysis of data using star [statistical tool for agricultural research]. philippine j. crop sci. 39 (supplement 1): 137. hossain, m.k., m.m. islam, a.a. mamun and s.m. abdullah and al. mamun. 2018. performance of sunflower genotypes in non-saline and saline soils of southern bangladesh. agron. j. 21(1): 1-7. islam, m.n, m.s. rahman, m.s. alom and m. akhteruzzaman. 2015. performance of different crops productivity enhancement through adaptation of crop varieties at char land in bangladesh. bangladesh j. agril. res. 40(4): 629-640. islam, m.n. and m. biswas. 2010. performance of soybean varieties in the char land area. annual res. report. agronomy division, bangladesh agril. res. institute, gazipur-1701. pp.97-98. islam, m.n., m. akhteruzzamam and s. rahman. 2010. performance of lentil varieties in char land areas. annual res. report. agronomy division, bangladesh agril. res. institute, gazipur-1701. pp.7677. mian, m.a.k. and m.r. islam. 2010. adaptation of bari released crop varieties in char land. annual res. report. agronomy division, bangladesh agril. res. institute, gazipur-1701. pp.93-94. nazrul, m.i. 2017. on-farm verification of linseed and sesame variety for fallow-fallow-t. aman rice cropping system in sylhet region of bangladesh. bangladesh agron. j. 20(1): 7-12. nazrul, m.i. and m.r. shaheb. 2012. screening of pulse crops for fallow land utilization in sylhet region. bangladesh agron. j. 15(2): 59-65. nazrul, m.i. and m.r. shaheb. 2014. performance of sweet gourd as relay with transplanted aman rice under rainfed ecosystem in sylhet region. bangladesh agron. j. 17(2): 47-53. nazrul, m.i., m.k. hasan and m.r.i. mondal. 2017. production potential and economics of mung bean in rice based cropping pattern in sylhet region under aez 20. bangladesh j. agril. res. 42(3): 413424. nazrul, m.i., m.r shaheb, m.a.h. khan and a.s.m.m.r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16(2): 41-50. nazrul, m.i., s.t. zannat and m.a. ali. 2020. evaluation on the field performance of different crops grown under acidic soil in sylhet region of bangladesh. int. j. sustain. crop prod. 15(1): 7-12. qadir, g. 2006. morpho-genetic expression of sunflower under varied temperature and moisture regimes. ph.d. thesis, university of arid agriculture, rawalpindi, pakistan. rahman, k.m.m. and p.m. schmitz. 2007. food production sustainability and security in bangladesh. bangladesh agricultural university, mymensingh and justus-liebig-university, giessen, germany. rahman, m.a., n.c.d. barma, m.h. sarker, m.m.r. sarker and m.i. nazrul. 2013. adaptability of wheat varieties in strongly acidic soils of sylhet. banagladesh j. agril. res. 38(1): 97-104. rakulan, g., l. pradheeban, k. nishanthanand and s. sivachandiran. 2016. effect of different height of earthing up on yield performance of groundnut under irrigated condition in kilinochchi district, sri lanka. world j. pharm. life sci. 2(4): 471-481. shaheb, m.r., m.i. nazrul and m. ali. 2012. performance of mustard varieties for fallow land utilization in sylhet region. bangladesh agron. j. 15(2): 47-52. on-farm adaptation of some oilseed crops under acidic soil of sylhet 95 world bank group. 2019. bangladesh climate-smart agriculture investment plan: investment opportunities in the agriculture sector’s transition to a climate resilient growth path. world bank, washington, dc. © world bank. https://openknowledge.worldbank.org/ handle/10986/32742 license: cc by 3.0 igo. https://openknowledge.worldbank.org/ on-farm adaptation of some oilseed crops under acidic soil of sylhet region in bangladesh *m. i. nazrul1 and m. akkas ali2 1pso, 2cso & head, ofrd, bari, bangladesh *corresponding email: mi_nazrul@yahoo.com bangladesh agron. j. 2025, 28(2): 89-94 effect of nutrient management on growth, yield and nutrient uptake in sorghum s. s. nasreen*, a. a. begum, s. s. kakon, j. a. chowdhury, m. z. ali, s. akther, m. a. h. khan and m. a. k. mian agronomy division, bangladesh agricultural research institute, gazipur 1701 *corresponding author, e-mail: shanjida03@gmail.com (received: 22 october 2025, accepted: 23 november 2025) keywords: total dry matter, spad value, balanced nutrient application abstract a two-year field study was conducted at agronomy research field, bari, gazipur, during rabi season of 2023-2024 and 2024-2025 to evaluate the effect of nutrient management on the growth, yield and nutrient uptake of sorghum. the experiment was conducted in randomized complete block design (rcbd) with 3 replications consisting five treatments viz., t1: 150-75-62.5-33.75-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t2: 120-60-50-27-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t3: 90-45-37.5-20.25-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t4: 6030-25-13.5-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t5: control (native fertility).the unit plot size was 3.6m × 3.6m. bari sorghum-1 seeds were sown on 29 november 2023 and 1 december 2024, respectively. plant spacing was maintained at 60 cm × 10 cm. one third of n and other fertilizer were applied as basal at final land preparation. the rest n was applied at 25 and 50 das in equal splits. data for growth analysis were taken at 35 days after sowing (das), 55 das, 75 das, 95 das and 115 das in the year of 2023-2024. chlorophyll content was measured using a spad meter (model spad-502, minolta crop, ramsey, nj). the yield component data was taken from randomly selected 10 plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise. the collected data were analyzed statistically and means were adjudged by lsd test at 5% level of significance using statistics 10. the highest spad value was observed at 60 das which declined gradually reaching the lowest at 90 das in all treatments. the highest spad values were observed in t1 treatment (28.1 at 35 das to 45.8 at 115 das) in the growing season. the results indicated that higher nutrient level showed higher spad values. the total dry matter (tdm) accumulation was slower up to 55 das then increased rapidly up to 95 das and afterwards increased slowly up to harvest. tdm accumulation was higher (1316 g m-2) at harvest in higher dose of fertilizer (t1) applied. t1 treatment (150-75-62.5-33.75-2.8-1.4 kg ha-1 of n-p-k-s-zn-b) produced the highest yield (4.5 t ha-1 in 2023–2024 and 3.9 t ha-1 in 2024–2025). the 1000-grain weight was also found higher in t1 (39.5 g in 2023–2024). nutrient uptake (n-p-k-s-zn-b) showed a positive correlation with sorghum grain yield. nutrient concentrations and uptake were influenced by nutrient levels. introduction in bangladesh and india, sorghum is commonly known as “jowar”. it is grown as a “safe” crop in the global agricultural ecosystem and is used as a staple food and fodder crop (kale et al., 2023). sorghum is important food and fodder crop in rabi and kharif season in bangladesh. among the different inputs, nutrients play vital role in crop productivity. the inadequate management of nitrogen, phosphorus and potassium is considered a major limiting factor for sorghum grain yield. generally, farmers of bangladesh are not using judicious levels of nutrients to the crop, hence not realizing potential yield of crop (mondal, 2011). the balanced nutrient management, helps to restore and sustain fertility and crop productivity. effective nutrient management is pivotal for maximizing sorghum yield, quality, and sustainability. by 90 nasreen et al. understanding sorghum's nutrient requirements, soil fertility, and implementing appropriate management practices, farmers can enhance productivity while minimizing environmental impact. continued research and adoption of innovative nutrient management strategies are essential for the sustainable cultivation of sorghum in diverse agricultural landscapes. there is no fertilizer recommendation for sorghum production in bangladesh. hence, the experiment was conducted to find out the optimum fertilizer for higher yield of sorghum. materials and methods field experiment was conducted at the agronomy research field of bari, gazipur during rabi season of 2023-2024 and 2024-2025. the soil of the research area belongs to the chihata series under aez-28. soils of the experimental plots were collected and analyzed. the physical and chemical properties of initial soil of the experimental plot has been presented in table1.the soil was clay loam with ph 5.69, om 1.25% (very low), total n 0.107% (low), exchangeable k 0.092 meq 100g soil−1 (low), available p 22.15 µg ml−1 (optimum), available s 25.63 µg g−1 (optimum), available zn 0.513 µg g−1 (low) and available b 0.235 µg g−1 (low). the experiment was consisted of five treatments viz., t1: 150-75-62.5-33.75-2.8-1.4 kg ha-1 of np-k-s-zn-b; t2: 120-60-50-27-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t3: 90-45-37.5-20.25-2.81.4 kg ha-1 of n-p-k-s-zn-b; t4: 60-30-25-13.5-2.8-1.4 kg ha-1 of n-p-k-s-zn-b; t5: control (native fertility). the experiment was laid out in a rcbd with three replications. the unit plot size was 3.6m × 3.6m. bari sorghum-1 seeds were sown on 29 november 2023 and 01 december 2024, respectively maintaining 60 cm line spacing and 10 cm plant to plant distance. one third n and all other fertilizer were applied as basal during final land preparation and rest n was applied at 25 and 50 das in two equal amounts. data for growth analysis and chlorophyll were taken in the year 2023-2024 only. in 2024-2025 growing season, growth data was not recorded due to technical problem. growth analysis data were recorded at 35 das, 55 das, 75 das, 95 das and 115 das. chlorophyll content was measured using a spad meter (model spad-502, minolta crop, ramsey, nj). the yield component data was taken from 10 randomly selected plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise. dry matter of crop was recorded at harvesting time. the collected data were analyzed statistically and means were adjudged by lsd test at 5% level of significance using statistics 10. table 1. initial soil analytical data of the experimental site at agronomy research field, gazipur ph oc (%) total n (%) exchangeable k (meq 100g-1 soil) available p (µg g-1 soil) available s (µg g-1 soil) available zn (µg g-1 soil) available b (µg g-1 soil) 5.69 1.25 0.107 0.092 22.15 25.63 0.513 0.235 vl l l o o l l critical levels 0.12 0.12 7.0 10.00 0.60 0.20 vl= very low, l= low, o= optimum results and discussion spad value was influenced by fertilizer level (fig. 1). the leaf greenness which indicated the leaf chlorophyll content was measured by spad meter. the highest spad value was observed at 60 das which declined progressively reaching the lowest at 90 das in all treatments. the highest spad values were observed in t1 treatment (from 28.1 at 35 das to 45.8 at 115 das) all through the growing season. the results indicated that higher nutrient effect of nutrient management on nutrient uptake in sorghum 91 level showed higher values of spad. higher nutrient dose enhanced greenness of leaves. similar results were reported by guo et al., 2025 (28.2 to 45.6 spad reading) during different stages of sorghum plant. fig. 1. spad value of sorghum at different days after sowing (das) as influenced by different nutrient management (2023-2024) total dry matter (tdm) accumulation was influenced (fig. 2) by different treatments. the tdm accumulation rate was slower up to 55 das then increased rapidly up to 95 das and then increased slowly up to harvest. tdm accumulation was less with native fertility and higher in higher dose of fertilizer (t1) applied (1316 g m−2) at harvest. fig. 2. total dry matter (tdm) accumulation of sorghum at different days after sowing (das) as influenced by nutrient management (2023-2024) yield components and yield of sorghum were affected (table 2) by different nutrient management practices except plant height. grain yield was significantly influenced by nutrient levels. among the treatments, t1 consistently showed superior performance, producing the tallest plants (137 cm), highest plant population (16.4 plants m−2² in 2023–2024), and the highest yields (4.5 t ha-1 in 2023–2024 and 3.9 t ha-1 in 2024-2025). t2 also performed well, although its yield was slightly lower than t1 which was statistically similar. but t3, t4 and especially t5 showed a gradual decline across all parameters, with t5 recording the lowest values in plant height, grain weight, and yield in both years. this result indicates the requirement of 92 nasreen et al. balanced fertilizer use for sorghum. a general decline in grain weight and yield was observed across all treatments in 2024–2025, possibly due to environmental factors. table 2. yield components and yield of sorghum as affected by different treatments treatments plant population (no. m-2) plant height (cm) 1000-grain weight (g) yield (t ha-1) 20232024 20242025 20232024 20242025 20232024 20242025 20232024 20242025 t1 16.4 13.3 137 137 39.5 36.2 4.50 3.94 t2 12.8 13.3 138 138 39.2 34.7 4.10 3.70 t3 12.1 13.2 129 133 36.2 34.2 3.50 3.49 t4 11.6 12.8 128 134 35.3 30.1 3.00 2.80 t5 11.9 12.5 127 129 32.9 29.4 2.50 2.20 lsd (0.05) 1.6 0.4 11.3 7.1 4.3 8.1 0.4 0.6 cv (%) 6.7 1.6 4.6 2.8 6.2 13.1 5.7 10.2 t1: 150-75-62.5-33.75-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t2: 120-60-50-27-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t3: 9045-37.5-20.25-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t4: 60-30-25-13.5-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t5: control (native fertility) 1000-grain weight showed a clear nutrient response, with the highest values in t1 and t2 in both years. it declined sharply in lower nutrient levels, particularly in t5. sorghum’s response to nutrient management varied significantly across years, with 2023-2024 outperforming 2024-2025 in yields. table 3. dry matter of sorghum as affected by different treatments at harvest treatments 2023-2024 2024-2025 grain (t ha-1) straw (t ha-1) grain (t ha-1) straw (t ha-1) t1 3.96 2.77 3.47 2.51 t2 3.61 2.68 3.26 2.40 t3 3.08 2.29 3.07 3.39 t4 2.64 1.97 2.46 1.98 t5 2.20 1.68 1.94 1.69 dry matter of sorghum as affected by different treatments at harvest has been showed in table 3. both grain and straw dry matter were produced higher by t1 treatment in both years. as a result nutrient uptake by grain (table 4 and table 5) and straw (table 6 and table 7) was affected by the grain and straw dry matter content. table 4. nutrient uptake in sorghum grain as affected by different treatments in 2023-2024 treatments n uptake k uptake p uptake s uptake t1 89.50 40.79 12.67 12.28 t2 66.03 38.61 12.27 11.18 t3 55.13 33.57 10.78 9.86 t4 46.46 29.30 9.77 8.45 t5 35.86 25.30 8.36 7.48 effect of nutrient management on nutrient uptake in sorghum 93 table 5. nutrient uptake in sorghum grain as affected by different treatments in 2024-2025 treatments n uptake k uptake p uptake s uptake t1 76.77 34.99 10.87 10.53 t2 59.58 34.84 11.07 10.09 t3 55.45 33.76 10.84 9.91 t4 43.37 27.35 9.12 7.88 t5 31.56 22.26 7.36 6.58 table 6. nutrient uptake in sorghum straw as affected by different treatments in 2023-2024 treatments n uptake k uptake p uptake s uptake t1 43.20 27.98 8.59 4.43 t2 33.84 27.07 8.31 4.29 t3 28.28 23.36 7.33 3.89 t4 23.92 20.09 6.30 3.55 t5 18.89 17.30 5.54 3.19 table 7. nutrient uptake in sorghum straw as affected by different treatments in 2024-2025 treatments n uptake k uptake p uptake s uptake t1 39.14 25.35 7.78 4.02 t2 30.30 24.24 7.44 3.84 t3 41.87 34.58 10.85 5.76 t4 24.05 20.20 6.34 3.56 t5 19.01 17.41 5.58 3.21 cost and return analysis of sorghum is showed in table 8. in both years. t1 generated the highest gross returns, with tk. 202500 in 2024 and tk. 177300 in 2025. table 8. cost and return analysis of sorghum cultivation as influenced by different treatments treatments gross return (tk.ha-1) 2024 gross return (tk.ha-1) 2025 total cost (tk.ha1) 2024 total cost (tk.ha1) 2025 gross margin (tk.ha-1) 2024 gross margin (tk.ha-1) 2025 bcr 2024 bcr 2025 t1 202500 177300 84500 85000 118000 92300 2.40 2.09 t2 184500 166500 80000 80500 104500 86000 2.31 2.07 t3 157500 157050 75500 76000 82000 81050 2.09 2.07 t4 135000 126000 71000 71500 64000 54500 1.90 1.76 t5 112500 99000 62000 62500 50500 36500 1.81 1.58 sorghum price tk. 45 kg-1 t1: 150-75-62.5-33.75-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t2: 120-60-50-27-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t3: 90-45-37.5-20.25-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t4: 60-30-25-13.5-2.8-1.4 kg ha−1 of n-p-k-s-zn-b; t5: control (native fertility) 94 nasreen et al. it also had the highest gross margins—tk. 118000 in 2024 and tk. 92300 in 2025 followed by t2, offering slightly lower gross returns and gross margins, but with reduced costs, resulting in a competitive bcr (2.40 in 2024 and 2.09 in 2025). notably, all treatments showed a decline in gross returns and gross margins from 2024 to 2025, possibly due to reduced yields. conclusion balanced and adequate nutrient application significantly enhanced sorghum growth, yield, and seed quality. the treatment t1 (150-75-62.5-33.75-2.8-1.4 kg ha-1 of n-p-k-s-zn-b) consistently outperformed others, followed by t2 (120-60-50-27-2.8-1.4 kg ha-1 of n-p-k-s-znb), suggesting that higher nutrient inputs result in superior crop performance. nutrient management, therefore, is the key for maximizing sorghum productivity, particularly in nutrientdeficient soils. references kale, s.s., n.r. chavan, n. chavan and g.v. kore. 2023. genetic diversity analysis in sorghum [sorghum bicolor (l.)] genotypes using ssr markers. pharma innov. j. 12(4): 1359–1364. mondal, m.h. 2011. causes of yield gaps and strategies for minimizing the gaps in different crops of bangladesh. bangladesh j. agric. res. 36(3): 469–476. guo, x., q. wu, l. wang, g. zhou, g. zhu, m.s.e. suliman and n.e.a. nimir. 2025. optimum nitrogen and phosphorus combination improves yield and nutrient use efficiency of sorghum in saline soil. plants. 14(1): 102. bangladesh agron. j. 2022, 25(2): 31-41 effect of defoliation on growth and yield of maize m.n. jahan, m.a. hasan and m.r. islam department of crop physiology and ecology, faculty of agriculture, hajee mohammad danesh science and technology university, dinajpur–5200, bangladesh corresponding e-mail: rabiulislam@hstu.ac.bd (received: 02 august 2022, accepted: 26 november 2022) keyword: defoliation, green fodder, light intensity, spad value, zea mays abstract the experiment was conducted to evaluate the effect of defoliation on grain and fodder yield of maize at the research field and laboratory of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur during the period of december 2018 to june 2019. the trial was carried out in a randomized completely block design with three replications. the experimental treatments were: t1– control (without leaf removal), t2– defoliating all leaves except ear and adjacent two leaves above the ear at 7 days after silking (das), t3–defoliating all leaves except ear and adjacent two leaves above the ear at 14das, t4–defoliating all leaves below the ear at 7 das, t5– defoliating all leaves below the ear at 14 das, t6– detopping except two leaves above the ear at 7 das and t7–detopping except two leaves above the ear at 14 das. light intensity was increased (66.9 to 81.05%) when only lower leaves (t5) or both upper and lower leaves (t2) were removed, but when only the upper leaves (t6) were removed it was not increased. spad value was increased (13.58 to 24.5%) but number of leaves and leaf area plant-1 were reduced (60.5 to 63.09% and 64.4%) due to defoliation. substantial amount of green fodder was obtained (0.776 kg m-2) due to defoliation of maize. grain yield of maize was reduced (5.56 to 21.83%) due to different defoliation treatments but the yield reduction was not significant when only lower (t4) or upper (t7) leaves were removed. introduction maize (zea mays l.) belongs to the family poaceae is the world’s most widely grown cereal and global production revealed 1398.3 million metric tons in 2018–2019 (usda, 2019), it is one of the most important crops in bangladesh, which can be well–fitted in the cropping systems (hashem et al., 1983). its demand is increasing day by day and becoming an important cereal crop for its high productivity and diversified use (food items for human, fodder for livestock, feeds for poultry, fuel and raw materials for industry) in bangladesh (islam and kaul, 1986). maize production in bangladesh was 3500 thousand metric ton in the year 2018–2019 (usda, 2019). maize can be conserved as silage, which is a nutritious green fodder for livestock. artificial defoliation provides lot of green fodder at the time of fodder scarcity; hence, defoliation in maize has great impact at broad spectrum for livestock production. location of individual leaves with respect to the ear and photosynthetic efficiency of a variety decides photosynthate translocation rate to the ear. it is estimated that the middle four leaves (2 above and 2 below the ear) approximately contributes 50 percent of the total dry matter accumulation in the ear (allison and watson, 1966). defoliation of maize hybrids at later developmental stages (e.g. v11, vt, r3 and r5) reduced grain yield (hicks et al., 1977). but, when defoliation of leaves occur after ear development; plant l have the advantage of some 32 jahan et al. photosynthetic activity of the leaves and therefore, produces more seeds than the leaves defoliated earlier. proper time and level of defoliation seems to be very important for controlling lodging and obtaining enough forage without reducing grain yield (usman et al., 2007). the information on proper timing and level of defoliation in maize leaves is scarce in bangladesh. therefore, the present study was conducted to know the impact of different levels of defoliation on growth and yield (grain and forage) of maize. materials and methods the experiment was set up at the research field (latitude, longitude and elevation were 25º39′ n, 88º41′ e and 37.58 m, respectively) of crop physiology and ecology department, hajee mohammad danesh science and technology university, dinajpur during december 2018 to june 2019. the unit plot size (2.4 m × 2.0 m) was used for the experiment. the research was conducted following randomized completely block design (rcbd) with three replications and seven treatments. the treatments were: t1 (control i.e. without leaf removal), t2 (defoliating all leaves except ear and adjacent two leaves above the ear at 7 das),t3 (defoliating all leaves except ear and adjacent two leaves above the ear at 14 das), t4 (defoliating all leaves below ear at 7 das), t5 (defoliating all leaves below ear at 14 das), t6 (detopping except two leaves above the ear at 7 das) and t7 (detopping except two leaves above the ear at 14 das). a fertilizer dose of 86.0, 26.0, 41.0, 19.0, 6.0, 1.0 and 0.5 kg ha-1 n, p, k, s, mg, zn and b was applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, magnesium sulphate, zinc sulphate and boric acid (frg, 2018). all fertilizers were applied as basal dose together with 1/3 urea and after irrigations 2/3 urea was top dressed. seeds of hybrid maize pac 293, advanta-brac were sown on december 1, 2018 at a row spacing of 60 and plant spacing 20 cm. two seeds were placed in each hole and after emergence healthy one seedling was kept. maize cobs harvested manually at physiological maturity stage (husk has turned yellow and the seeds were hard enough), dehusked and dried separately under shade. shelling was done with single cob maize sheller and seeds were dried under shade till moisture content reached 12%. five maize plants from each plot were randomly selected for data collection. the parameters first cob height, leaf number plant-1, light intensity in crop canopy and spad (soil plant analyses development) values were collected at 21, 28 and 35 das. light intensity in crop canopy (lux) was recorded using light meter (model: lx–102, origin: china) at noon under bright sunshine and less wind conditions. the sensor of the instruments was placed on the ground level at away from the edges of four corners. spad value was recorded from tagged plants from each plot using self–calibrating minolta chlorophyll meter (model: spad– 505, minolta co. ltd., japan) using the middle portion of cob bearing leaves. leaf area (cm2) was calculated using the formula of kvet et al. (1971) as leaf area plant-1 = mean leaf area × 0.75 × leaf number; where, 0.75 is a factor. cob length, cob diameter, number of rows of grains cob–1, number of grains row-1, grain number cob-1, single cob weight, weight of hundred grains, and grain, stover and green fodder yield also evaluated. the data were analyzed using statistix 10 program and treatment means compared by tukey’s range test at p ≤ 5% level. results and discussion growth parameters, light intensity and spad values of maize growth attributes such as the first cob height (figure 1) of maize plants was not significantly influenced by different defoliation treatments at 21, 28 and 35 days after silking (das) but number of leaves (figure 2) and leaf area plant-1 (figure 3) varied significantly. the maximum number of leaves were obtained by t1 (10.84, 10.66 and 10.13, respectively) followed by t7, effect of defoliation on growth and yield of maize 33 t6, t5 and t4; whereas the lowest number of leaves (4.00) in t2 and t3 treatments. the maximum leaf area plant-1 (0.749 m2) was recorded in t1 which was followed by t7, t4, t5 and t6 treatments and the lowest (0.2667 m2) in t2 which was statistically similar to t3 treatment. here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das, treatment means compared by tukey’s range test at p ≤ 5% level. fig. 1. effect of defoliation on first cob height of plant at 21, 28 and 35 das in maize. here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das. treatment means compared by tukey’s range test at p ≤ 5% level. fig. 2. effect of defoliation on number of leaf plant-1at 21, 28 and 35 das in maize. 80 82 84 86 88 90 92 94 96 98 100 21 das 28 das 35 das f ir st c o b h e ig h t (c m ) treatments t1 t2 t3 t4 t5 t6 t7 a a a c c c c c c b b b b b b b b b b b b 0 1 2 3 4 5 6 7 8 9 10 11 12 21 das 28 das 35 das n o . o f le a f treatments t1 t2 t3 t4 t5 t6 t7 34 jahan et al. here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das. treatment means compared by tukey’s range test at p ≤ 5% level. fig. 3. effect of different levels of defoliation on leaf area plant-1 in maize. the light intensity in canopy (figure 4) and spad values of leaves (figure 5) at 21, 28 and 35 das were significantly influenced by different defoliation treatments of maize. the maximum light intensity in canopy (9.84 thousand lux) at 21 das was recorded in t2 which was followed by t5, t4 and t3 and the lowest light intensity in canopy (5.08 thousand lux) in t6 which was statistically identical to t7 and t1 treatment. similar pattern of light intensity in canopy also found at 28 and 35 das. the maximum spad value (55.86) at 21 das was found in t3 which was statistically at par to t6, t4, t2, t7 and t5 treatments. the lowest spad value (47.56) was recorded in t1 treatment. the maximum spad value (55.2) at 28 das was found in t7 which was statistically identical to those observed in t3, t5, t4 and t6 treatments. the lowest spad value (46.6) was recorded in t2followed by t1 treatment. the maize plant showed almost similar spad values at 35 das as like as 28 das. the significant differences in number of leaves at 21, 28 and 35 das was noticed and it might be due to the obligation of defoliation treatments after 7 and 14 das. these findings are quite similar to those of vasilas and seif (1985) in corn. they revealed significant differences in number of leaves, leaf area plant-1 and lai at 90 das and at harvest noticed among the levels of defoliation may be due to imposition of defoliation treatments after 65 das. removing of leaves either 3 or 4 had a greater impact on lai than removal of 1 and 2 leaves because of the difference in size of leaves; leaves nearest ear were larger than those further from the ear (keating and wafula 1992). effects of leaf removing on lai were different according to the intensity of defoliation and leaf position (barimavandi et al., 2010). the results of the present study revealed that when only lower leaves or both upper and lower leaves removed, the canopy density at lower portion was decreased and light intensity was increased but when only the upper leaves were removed light intensity in the canopy was not increased. heidari (2012) also reported that the upper leaves are more efficient in absorbing light than lower leaves. the variation in spad value due to application of leaf clipping and density was found more a d d c c c b 0 1 2 3 4 5 6 7 8 t1 t2 t3 t4 t5 t6 t7 l e a f a re a p e r p la n t (t h o u sa n d c m 2 ) treatment effect of defoliation on growth and yield of maize 35 conspicuously at later stage of crop growth rather than early stages. in general, the higher the level of leaf clipping, higher was the spad value at the later stage of crop growth except highest density of leaf clipping (d3c4). here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das. treatment means compared by tukey’s range test at p ≤ 5% level. fig. 4. effect of defoliation on light intensity in canopy at 21, 28 and 35 das in maize. here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das. treatment means compared by tukey’s range test at p ≤ 5% level. fig. 5. effect of defoliation on spad value at 21, 28 and 35 das in maize. d c d a a a c a c c b c b a b d e d d e c e 0 1 2 3 4 5 6 7 8 9 10 11 21 das 28 das 35 das l ig h t in te n si ty ( t h o u sa n d l u x ) treatment t1 t2 t3 t4 t5 t6 t7 b b c a b c a a ab a a b c ab a ab a a ab ab a a 30 35 40 45 50 55 60 65 70 21 das 28 das 35 das s p a d v a lu e treatments t1 t2 t3 t4 t5 t6 t7 36 jahan et al. regardless of density spad value in every treatment plants declined sharply from 14 das compared to clipping treatments. this might be due to the greater demand of cob development and its maturation along with scarcity of leaves (emran, 2010). yield contributing traits yield contributing traits such as cob length, number of grains row–1, and number of grains cob-1, single cob weight, grain weight cob-1, 100-grain weight were significantly influenced by different defoliation treatments but cob diameter and number of rows cob–1 insignificant (table 1). the maximum cob length (17.01 cm) was found in t7 which was followed by t6 and t5 and the lowest cob length (14.41 cm) in t2 which followed by t3. however, the cob length was reduced 8.39 percent in t2, 3.6 percent at 14 das (t3), while it was increased 5.72% in treatmentt4, 6.48% in t5, 6.99% at t6 and 8.13% in treatment t7. the percent reduction in number of grains row-1 were 19.78 in treatment t2, while 3.31, 4.72, 1.05, 2.62, t3, 3.31% reduction revealed in t4, t5, t6 and t7 treatments, respectively. the maximum number of grains cob-1 (573.25) was found in t1 which was statistically identical to t4, t5, t7 and t3 treatments and the lowest number of grains cob-1 (472.33) in t2. defoliating all leaves except ear and adjacent two leaves above the ear at 7 das (t2) reduced the number of grains cob-1 compared to other treatments. the highest single cob weight (185.8 g) was found in t1 which was statistically identical to t4, t7 and t5 treatments and the lowest single cob weight (130.5 g) in t2. however, the percent reduction in single cob weight were 29.76 percent in t2, 13.61 percent in t3, 5.16 percent in t4, 6.67 percent in t5, 10.22 percent in t6 and 5.22 percent in t7 treatments. the maximum grain weight cob-1(156.9 g) was recorded in t1 which was statistically similar to t4 and t7. the lowest grain weight cob-1 (112.6 g) was obtained from in t2 treatment. however, the percent reduction in grain weight cob-1 were 28.23 percent in t2, 12.81 percent in t3, 4.39 percent in t4, 6.30 percent in t5, 9.24 percent in t6 and 3.95 percent in t7 treatments. the maximum 100–grain weight (28.93 g) was found in t1 which was statistically identical to t4, t5, t7 and t6 treatments and the lowest 100–grain weight (25.86 g) in t2 treatments. however, the percent reduction in 100–grain weight, were 10.61 percent in t2, 4.59 percent in t3, 1.97 percent in t4, 0.95 percent in t5, 3.45 percent in t6 and 2.86 percent in t7 treatment. the intensities of defoliation and position of leaves on the plant and defoliation time are the most effective factors on the ear length (tilahun, 1993). emam et al. (2013) and souza et al. (2015) revealed the artificial defoliation in reproductive stages responsible for reduction of cob length. these outputs support the present findings. leaf situated one or two above the ear is the principle source of assimilates for the cob development. reductions of the ear diameter in maize at vegetative and reproductive stages due to defoliation were observed by souza et al. (2015), this result is in parallel with the present findings. this result are in accordance with the findings of barimavandi et al. (2010), heidari (2013) and jalilian and delkhoshi (2014) who reported that removing of above leaves of ear could decrease the number of grains in row. kabiri (1996) and echarte et al. (2006) stated that leaf removal at 50% silking resulted in the loss of grain number and so, less stem reserves were exploited because of the deficiency of physiological sinks. these outputs support the findings of present investigation. according to alvim et al. (2011), photosynthetically active leaf area loss above the ear affects the cob mass of maize due to defoliation. zewdu and asregid (2001) also reported that cob weight was reduced under defoliation. heidari (2012) who noted that cob weight was decreased with increasing defoliation intensity. presence of two above leaves is important to form ear with thick and big skin. this skin photosynthesis and reserves had a remarkable effect on row number, length and weight of cob. these findings are in agreements with the present outputs. it seems that seed weight is more dependent on genetic factors than environmental factors (heidari et al., 2009). however, effect of defoliation on growth and yield of maize 37 it was reported that in maize no defoliation produced the maximum seed weight cob-1 and minimum seed weight cob-1 was obtained in defoliation of all leaves below cob at two weeks after mid silking stage (chaudhary et al., 2005). the reason for decreasing grain weight cob-1 in d1 might be due to lower dry matter accumulation and less translocation of assimilates to grains as affected by early stages of detopping (maposse and nhampalele, 2009). assimilate availability can effect mean grain weight at early grain development stages, so that increasing availability of assimilate at later stages of grain filling would not affect mean grain weight (lauer et al. 2004). table 1. influence of different levels of defoliation on yield contributing traits of maize at different days after silking treatments cob length cob diameter number of rows cob–1 number of grains row–1 cm % change over control cm % change over control no. % change over control no. % change over control t1 15.73 d – 15.52 – 15.06 – 38.06 a – t2 14.41 f –8.39 14.54 –6.31 15.46 +2.65 30.53 b –19.78 t3 15.15 e –3.60 15.17 –2.25 14.80 –1.72 36.80 a –3.31 t4 16.60 c +5.72 15.37 –0.96 15.46 +2.65 36.26 a –4.72 t5 16.75 bc +6.48 15.14 –2.44 14.80 –1.72 37.66 a –1.05 t6 16.83 b +6.99 15.01 –3.28 14.13 –6.17 37.06 a –2.62 t7 17.01 a +8.13 15.31 –1.35 14.80 –1.72 36.80 a –3.31 cv (%) 4.35 3.29 3.11 1.42 table 1 continued treatments number of grains cob-1 single cob weight grain weight cob-1 100 -grain weight no. % change over control g % change over control g % change over control g % change over control t1 573.25 a – 185.8 a – 156.9 a – 28.93 a – t2 472.33 c –17.60 130.5 d –29.76 112.6 d –28.23 25.86 c –10.61 t3 544.77 ab –4.96 160.5 c –13.61 136.8 cd –12.81 27.60 b –4.59 t4 560.93 ab –2.14 176.2 ab –5.16 150.0 ab –4.39 28.36 ab –1.97 t5 557.38 ab –2.76 173.4 ab –6.67 147.0 b –6.30 28.66 ab –0.95 t6 524.00 b –8.59 166.8 bc –10.22 142.4 c –9.24 27.93 ab –3.45 t7 545.58 ab –4.82 176.1 ab –5.22 150.7ab –3.95 28.10 ab –2.86 cv (%) 3.70 4.05 13.07 2.21% here, t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das, treatment means compared by tukey’s range test at p ≤ 5% level. defoliating all leaves except ear and adjacent two leaves above the ear at 7 das (t2) reduced the 100–grain weight compared to other treatments (table 1). these results are in accordance with the findings of emam et al. (2013) who reported that maximum 1000–grain weight (220 g) was obtained from control as well as 50% defoliation at 30 days after mid–silking and minimum (90 g) was obtained from 100% defoliation at mid–silking. jalilian and delkhoshi (2014) observed the effect of leaf clipping treatments on the 1000 -grain weight was significant. 38 jahan et al. grain, fodder and stover yields of maize table 2 reveals that different yields of maize such as grain, green fodder and stover yields were significantly influenced due to various defoliation treatments. the maximum grain yield (1193 g m-2) was found in t5 which was statistically identical to t7 and t1 treatments and the lowest grain yield (913 g m-2) in t2 treatments. however, the percent reduction in grain yield were 21.83 percent in t2 treatment , 11.81 percent in t3, 5.56 percent in (t4) and 6.25 percent in treatment t6 and the percent increase in grain yield were 2.14 percent in t5, and 0.06 percent when detopping done except two leaves above the ear at 14 das (t7). table 2. influence of different levels of defoliation on yields of maize at different days after silking treatments grain yield green fodder yield stover yield plant-1 g m-2 % change over control g m-2 g % change over control t1 1160 ab – 0.00 f 209.40 a – t2 910 d –21.83 776.06 a 151.40 c –27.69 t3 1030 c –11.81 758.40 a 162.90 bc –22.20 t4 1100 bc –5.56 706.50 b 196.40 ab –6.20 t5 1193 a +2.14 587.10 c 171.80 bc –17.95 t6 1090 bc –6.25 489.10 e 192.60 ab –8.02 t7 1170 ab +0.06 547.80d 220.40 a +5.25 cv (%) 4.39 2.26 9.93 t1 = control (without leaf removal), t2 =defoliating all leaves except ear and adjacent two leaves above the ear at 7 das, t3 = defoliating all leaves except ear and adjacent two leaves above the ear at 14 das, t4 = defoliating all leaves below ear at 7 das, t5 = defoliating all leaves below ear at 14 das, t6 = detopping except two leaves above the ear at 7 das and t7 = detopping except two leaves above the ear at 14 das, treatment means compared by tukey’s range test at p ≤ 5% level. defoliating all leaves except ear and adjacent two leaves above the ear at 7 das (t2) reduced the grain yield compared to other treatments. the maximum green fodder yield (776.06 g m-2) was found in t2 which was statistically identical to t3 and the lowest green fodder yield (0.00 g m-2) was found in t1 which was followed by t7 and t6. the maximum stover yield plant-1 (220.4 g) was found in t7 which was statistically identical to t1, t4 and t6 treatments and the lowest stover yield plant-1 (151.4 g) in t2 which was at par to t5 and t3 treatments. however, the percent reduction in stover yield plant-1 were 27.69 percent in t2, 22.20 percent in t3, 6.20 percent in t4, 17.95 percent in t5, 8.02 percent in t6 and the percent reduction in stover yield plant-1 was 5.25 percent in t7. grain yield is the product of number of plant m-2, cobs plant-1, grains cob-1 and individual grain weight. a change in any of these characters due to defoliation ultimately affects the grain yield. hassen (2003) reported that the seed yield and stover yield of maize were significantly influenced by the rate of various defoliation levels (0, 25, 50, 75 and 100%). however, adee et al. (2005) calculated that the upper 8 to 10 leaves contributed 88% of the grain yield. grain yield losses associated with defoliations around tasseling/silking are mainly explained by fewer kernel number (kn) (severini et al., 2011), while losses for defoliations right before or at grain filling period (r2, blister stage and on) are largely related to decline in kernel weight (echarte et al., 2006; abendroth et al., 2011). reduction in yield with defoliation treatment in maize was reported by gaias et al. (2017), battaglia (2014), heidari (2017) and alvim et al. (2011). defoliation of all leaves above ear (l3) recorded lesser dry matter production compared to other effect of defoliation on growth and yield of maize 39 levels of defoliation which may be due to heavy loss of foliage’s and photosynthetically active leaf area and their inability to intercept the light which resulted in inadequate synthesis of food reserves. hassen (2003) reported that the grain yield and stover yield of maize were significantly influenced by the rate of defoliation (0, 25, 50, 75 and 100%) treatments. conclusion from the overall results it was concluded that light intensity in the crop canopy was increased when only lower leaves or both upper and lower leaves were removed, but when only the upper leaves were removed light intensity in the canopy was not increased. spad value which indicated the greenness of leaf was increased due to defoliation. grain yield of maize was reduced due to different defoliation treatments but the yield reduction was not significant when only lower or upper leaves were removed and it was significant when both upper and lower leaves were removed. so, farmers could harvest green fodder either from lower or upper leaves to ear without significant yield reduction of maize. references abendroth, l.j., r.w. elmore, m.j. boyer and s.k. marlay. 2011. corn growth and development, pmr 1009. iowa state university extension, ames, iowa. adee, e.a., l.e. paul, e.d. nafziger and g. bollero. 2005. yield loss of corn hybrids to incremental defoliation. crop manag. 4(1), doi:10.1094/cm-2005-0427-01-rs. allison, j.c.s. and d.j. watson. 1966. the production and distribution of dry matter in maize after flowering. ann. bot. 30: 365–38. alvim, k.r.t., c.h. brito, a.m. brandão, l.s. gomes and m.t.g. lopes. 2011. redução da área foliar em plantas de milho na fase reprodutiva. revista ceres. 58: 413–418. barimavandi, a.r., s. sedaghathoor and r. ansari. 2010. effect of different defoliation treatments on yield and yield components in maize (zea mays l.) cultivar of s.c704. aust. j. crop sci. 4(1): 9–15. battaglia, m.l. 2014. corn (zea mays l.) yield response to defoliation at different row widths. an m. sc. (crop science) thesis. department of food and environment, university of kentucky, kentucky. bortoline, p.c., a. moraes and p.c. carvalho. 2005. forage and grain yield of white oat under grazing. revista.brasileira–de–zo tecnia. 34(6, supl): 2192–2199. chaudhary, a.n., m.i. latif, m. haroon ur–rasheed and ghulam–jilani. 2005. profitability increase in maize production through fertilizer management and defoliation under rain fed cropping. int. j. biol. biotech. 2(4): 1007–1012. echarte, l., f.h. andrade, v.o. sadras and p. abbate. 2006. kernel weight and its response to source manipulations during grain filling in argentinean maize hybrids released in different decades. field crops res. 96: 307–312. emam, y., h. bahrani and k. maghsoudi. 2013. effect of leaf defoliation on assimilate partitioning in maize (zea mays l.) hybrid sc. 704. sci. j. agron. plant breed. 1(1): 26–33. emran, s.a. 2010. source–sink manipulation and population density effects on green fodder and grain yield in hybrid maize. m. s. thesis. bsmrau, salna, gazipur. pp. 63–81. fao, 2019. food and agriculture organization of the united nations (fao). global cereal production. available: www.fao.org. 40 jahan et al. frg, 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc), farmgate, dhaka 1215. p. 90. gaias, w.l., e.r. gibbert, l.p.s. chidichima, c. hendges and a.l. muller. 2017. corn crop performance in different levels of defoliation. j. agric. sci. 10: 354–360. gardner, p.f., r.b. pearce and r.l. mitchell. 1985. physiology of crop plants lowa state university press. ames. usa. pp. 31-32. hashem, a., a. quasem, m.s. uddin, m. jahiruddin and r.n. mallick. 1983. the performance of different cropping patterns in 1982–1983 at the cropping systems research site, hathazari, chittagong, regional agricultural research station, hathazari, chittagong. hassen, h. 2003. effect of defoliation on yield components of maize and under sown forage. agri. topica. 18(1/2): 5–7. heidari, h. 2017. effect of defoliation and ½ ear removal treatments on maize seed yield and seed germination. biharean biologist. 11(2): 102–105. heidari h. 2013. yield, yield components and seed germination of maize (zea mays l.) at different defoliation and tassel removal treatments. philipine agril. scientists. 96(1): 42–47. heidari, h. 2012. effect of defoliation intensity on maize yield, yield components and seed germination. life sci. j. 9(4): 1587–1590. heidari, h., s. bahraminejad, g. maleki and a.h. papzan. 2009. response of cumin (cuminum cyminum l.) to sowing date and plant density. res. j. agric. biol. sci. 5(4): 597–602. hicks, d.r., w.w. nelson and j.h. ford. 1977. defoliation effects on corn hybrids adapted to the northern corn belt. agron. j. 69: 387–390. islam, t.m. t and a.k. kaul. 1986. prospects of maize in bangladesh. fao/undp. dhaka, bangladesh. pp. 105-109. jalilian, j. and h. delkhoshi. 2014. how much, leaves near the ear contribute on yield and yield components of maize ? cercet. agron. mold. 47(2): 5-12. kabiri, m. 1996. study on effect of source: sink change and the role of unstable stem reserve on yield of two sweet corn cultivers. m.sc. thesis. department of agriculture, karaj, iran. keating, b.a. and p.s carberry. 1993. resources capture and use in intercropping; solar radiation. field crops res. 34: 273-301. keating, b.a. and b.m. wafula. 1992. modelling the fully expanded area of maize leaves. field crops res. 29: 163-176. khaliliaqdam, n., a. soltani, t. mir–mahmoodi and t. jadidi. 2012. effect of leaf defoliation on some agronomical traits of corn. world appl. sci. j. 20(4): 545–548. kvet, j., j.p. ondok and p.g. jarvis. 1971. method of growth analysis. in: sestak z. j. catsky and p. g. jarvis. (ed.). plant photosynthetic production: manual and methods. the hugue; the hugue publisher. pp. 343-384. lauer, j.g., g.w. roth and m.g. bertram. 2004. impact of defoliation on corn forage yield. agron. j. 96: 1459–1463. magalhães, p.c. and f.o.m. durães. 2006. fisiologia da produção de milho. sete lagoas: embrapa milho e sorgo. 10p. (embrapa milho e sorgo. circular técnica, 76). maposse, i.c. and v.v. nhampalele. 2009. performance of cowpea varieties under different defoliation regimes for multiple uses. in: african crop science conference proceedings. 9: 279–281. effect of defoliation on growth and yield of maize 41 pereira, m.j.r., e.c.b. bonan, a. garcia, r.l. vasconcelos, k.s. giacomo and m.f. lima. 2012. características morfoagronômicas do milho submetido a diferentes níveis de desfolha manual. revista ceres. 59(2): 200–205. severini, a.d., l. borras, m.e. westgate and a.g. cirilo. 2011. kernel number and kernel weight determination in dent and popcorn maize. field crops res. 120: 360–369. souza, v.q., i.r. carvalho, d.n. follmann, m. nardino, r. bellé, d. baretta and d. schmidt. 2015. desfolhamento artificial e seus efeitosnos caracteres morfológicos e produtivosem híbridos de milho. revista brasileira de milho e sorgo. 14: 61–74. tilahun, a. 1993. quantitative and physiological traits in maize (zea mays). associate with different levels of moisture, plant density and leaf defoliation in ethiopia in: proceedings of the first national maize workshop of ethiopia. benti t. and ransom j.k. (eds.).pp. 74-80. iar/cimmyt, addis ababa. umashankara, k.b. 2007. influence of stages and levels of defoliation on seed yield and quality in fodder maize (cv. south african tall). an m. sc. (ag) thesis. department of seed science and technology, dharwad university of agricultural sciences, dharwad – 580005. usda, 2019. united states department of agriculture (usda).world agricultural production, foreign agricultural service. p.14. usman, k., e.j. khan, q. khan, a. wakil and m.u. khan. 2007. effect of detopping on forage and grain yield of rice under agro–climatic conditions of d.i. khan. sarhad j. agric. 23(1): 1–4. vasilas, b.l. and r.d. seif. 1985. defoliation effects on two corn inbreds and their single–cross hybrid. agron. j. 77: 816–820. zewdu, t. and d. asregid. 2001. effect of growing annual forage legumes with maize and maize leaf defoliation on grain and stover yield components and under sown forage production. in: 7th eastern and southern africa regional maize conference, nairobi. pp. 487–490. bangladesh agron. j. 2024, 27(1): 1-8 determination of different doses of herbicide (clio) to control weeds in maize field m.r. karim1*, j.a. chowdhury1, t.a. mujahidi2, m.m. karim3, s. mazumder4 and s.k. paul1,5 1agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh 2bangladesh agricultural research institute, rars, hathazari, bangladesh 3oilseed research center, bangladesh agricultural research institute, gazipur-1701, bangladesh 4sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka-1207, bangladesh 5the university of newcastle, callaghan, 2308, nsw, australia *corresponding author, email: mrkarimsau09@gmail.com (received: 09 september 2024, accepted: 31 march 2025) keywords: herbicide, clio, weeds, maize abstract various weed management practices including physical, mechanical, biological and chemical methods are commonly applied by the farmers. of all possible weed control practices, use of chemicals (herbicides) stands first and a large number of herbicide groups having different mode of actions are commonly used. however, considering the effectiveness and safe use with eco-toxicological aspect, it is important to finalize the optimum dose before application to the farmer’s fields. an experiment was conducted at the research field of agronomy division, joydebpur, gazipur during the kharif-1 season of 2017 and rabi 2017-2018 to find out the optimum rate of herbicide (clio) to control weeds in maize field for getting higher yield. six treatments viz., i) clio @35 ml ha−1, ii) clio @55 ml ha−1, iii) clio @75 ml ha−1, iv) clio @95 ml ha−1, v) clio @115 ml ha−1 and vi) control were tested on maize (cv. bari hybrid maize-9). herbicides were sprayed at 10 days after sowing (das) according to treatments. weed samples were taken at 25 and 45 das. major weeds flora were bathua (chenopodium album), durba (cynadon dactylon), anguli (digitaria sanguinalis), helencha (jussica repens), hatishur (heliotropium indicum), shama (echinochloa crusgalli), bangchora, swetlomy (gnaphalium japonicum), mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (eleusine indica), bon masur (vicia sp.). weed dry matter weight significantly varied in different treatments. weed relative density were highest in no weeding in both kharif-i, 2017 and rabi 2017-18. the highest dry weight of weeds at 25 das (14.15 g m−2) and (15.16 g m−2) and at 45 das (44.31 g m−2) and (48.37 g m−2), respectively in kharif-1, 2017 and rabi 2017-18 were found in control plot whereas the lowest in spraying of clio @115 gm m−2 both at 25 and 45 das. the maximum weed control efficiency (wce) over control both at 25 das (84.95% in kharif-, 2017 and 89.95% in rabi 2017-18) and at 45 das (80.48% in kharifi, 2017 and 89.45% in rabi 2017-18), respectively in spraying of clio @115 ml ha−1. the maximum grain yield both in kharif-i, 2017(9.77 t ha−1) and rabi 2017-18 (9.51 t ha−1) was found in spraying of clio @115 ml ha−1 which was statistically identical with spraying of clio @75 ml ha−1 and 95.00 ml ha−1 and lowest in no weeding. the highest marginal benefit–cost ratio (mbcr) both in kharif-1, 2017 (2.28) and rabi 2017-18 (2.41) was observed in spraying of clio @95 ml ha−1 and lowest in no weeding. results revealed that application of clio @ 95 ml ha−1 at 10 das of maize is economical viable, and it needs further trial to investigate eco-toxicological consequences to environment and living organisms after application. introduction maize is an important cereal crop in bangladesh. it ranks 3rd after rice and wheat. its demand and production area is increasing day by day. it is used as feed for poultry, fodder for 2 karim et al. livestock and also used as various food items. hybrid maize is a high yield potential cereal crop (jahan, 2014). its yield potential varies depending on variety, season and management practices. among management options, weeding is the most critical one. weed infestation reduces crop yield every year. weeds cause around 33% of total crop loss in asia and other countries (oerke, 2006., kobir et al., 2019, paul et al., 2019., kobir et al., 2021., paul et al., 2022., paul et al., 2024b). on an average 37.3% of crop produce is damaged by weeds in bangladesh. various weed management practices including physical, mechanical, biological and chemical methods are commonly applied by the farmers. of all possible weed control practices, use of chemicals (herbicides) stands first and a large number of herbicide groups having different mode of actions are commonly used. however, considering the effectiveness and safe use with eco-toxicological aspect, it is important to finalise the optimum dose before application to the farmer’s fields. in bangladesh different chemicals were used to control weeds (hajong et al., 2015, mondal et al., 2015, hajong et al., 2016, khan et al., 2016, haque, 2017). these chemicals are very much costly and have residual effects (ahmed et al., 2016, paul and naidu, 2022, paul et al., 2024a,). this is also harmful for the environment and health of human beings. the indiscriminant use of herbicide destroys soil health (paul et al., 2023, paul et al., 2024a, paul et al., 2024b). literature revealed that clio is effective at lower dose in controlling weeds in maize field. it is a post emergence herbicide which contains a new active ingredient namely topramezone, a new subclass of the hallucinogen persisting perception disorder (hppd)-inhibiting herbicide. as a result, the possibility of adverse effect of this herbicide is lower than other herbicides. hence, the experiment was conducted to determine the optimum dose of herbicide (clio) to control weeds in maize field. materials and methods an experiment was conducted at the research field of agronomy division, joydebpur, gazipur during the kharif-1 season of 2017 and rabi 2017-2018 to find out the optimum rate of herbicide (clio) to control weeds in maize field for getting higher yield. the land was medium high and the soil was clay loam in texture. six treatments viz., i) clio @35 ml ha−1, ii) clio @55 ml ha−1, iii) clio @75 ml ha−1, iv) clio @95 ml ha−1, v) clio @115 ml ha−1, vi) no weeding were tested in this study. the unit plot size was 3m × 4m. hybrid maize (var. bari hybrid maize-9) was shown on 03 april 2017 (for kharif-1 season of 2017) and 17 november (for rabi 2017-2018) with 60 × 20 cm spacing. maize was fertilized with 190-9075-80-7 kg ha−1 of n, p, k, s, zn (frg, 2012) as urea, triple superphosphate (tsp), muriate of potash (mop), gypsum and zinc sulphate. one third of n, whole amount of tsp, mop, gypsum, zinc sulphate and boric acid were applied as basal. remaining 2/3 n was top dressed at 25 and 45 (days after sowing) das. three irrigations were given to the crop at 21, 45 and 60 das. herbicides were sprayed with a knapsack sprayer at 10 das. all other operations were done as and when required. weed samples were collected at 25 and 45 das. data on yield components were taken from 10 plants and grain yield was taken from whole plot. collected data were analyzed statistically using mstat-c program. the relative density (rd) and weed control efficiency (wce) were calculated by the following formula. relative density (rd) = no. of specific weed species total no. of weeds ×100 weed control efficiency (wce) = dry wt. of control plot -dry wt. of specific plot dry wt. of control plot ×100 results and discussion the results revealed that clio has better weed control efficacy in maize field fields. it contains a new active ingredient namely topramezone, a new subclass of the hppd-inhibiting determination of different doses of herbicide to control weeds in maize field 3 herbicide. as a result, the possibility of adverse effect of this herbicide is lower than other herbicides. major weeds flora in the experiment was bathua (chenopdium album), durba (cyradon dactylon), anguli (digitaria sanguinalis), helencha (jussica repens), hatishur (heliotropium indicum), shama (echinochola crusgalli), bangchora, swetlomy (gnaphlium japonicum), mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (elusine indica), and bon masur (vicia sp.). weed relative density were highest in no weeding condition in both kharif-1, 2017 and rabi 2017-18 (table 1). table 1. weed infestation in maize field at 30 and 60 days after seedling (das) treatments weeds species number of weeds m−2 relative density (%) local name scientific name 25 das 45 das 25 das 45 das kharif 2017 rabi 201718 kharif 2017 rabi 201718 kharif 2017 rabi 201718 kharif 2017 rabi 2017-18 clio @35 ml ha−1 bathua chenopodium album 2 5 6 2 2.74 12.50 5.79 4.90 durba cynadon dactylon 14 11 17 5 19.18 2.78 16.35 5.89 anguli digitaria sanguinalis 3 0 6 0 4.11 4.17 5.79 9.80 helencha jussica repens 3 4 7 6 4.11 16.67 6.73 5.89 hatishur heliotropium indicum 1 2 3 2 1.37 4.17 2.88 3.90 shama echinochloa crusgalli 25 11 32 10 34.25 12.50 30.74 28.43 bangchora 3 2 4 4 4.11 2.78 3.84 9.80 swelomy gnaphalium japonicum 0 1 1 0 0.96 0 mutha cyperus rotundus 3 3 7 2 4.11 19.44 6.73 7.85 shaknote amaranthus viridis 1 2 2 3 1.37 9.72 1.92 5.89 gaicha paspalum commersonii 2 4 1 2.74 4.17 0.96 0 chapra eleusine indica 16 8 18 8 21.91 5.55 17.31 11.76 bon masur vicia sp. 7 1 5.55 5.89 total 73 84 104 93 100 100 100 100 clio @55 ml ha−1 bathua c. album 5 5 9 5 10.64 5.45 12.50 2.74 durba c. dactylon 1 1 2 6 2.13 6.36 2.78 19.18 anguli digitaria sanguinalis 0 0 3 10 0 14.55 4.17 4.11 helencha jussica repens 6 6 12 6 12.76 7.28 16.67 4.11 hatishur heliotropium indicum 0 0 3 4 0 6.36 4.17 1.37 shama echinochloa crusgalli 12 12 9 29 25.53 22.73 12.50 34.25 bangchora 0 0 2 10 0 2.78 4.11 swetlomy gnaphalium japonicum 0 1.81 0 mutha cyperus rotundus 11 11 14 8 23.41 10.91 19.44 4.11 shaknote amaranthus viridis 3 3 7 6 6.38 7.28 9.72 1.37 gaicha paspalum commersonii 1 1 3 0 2.13 0.91 4.17 2.74 chapra eleusine indica 6 6 4 12 12.76 10 5.55 21.91 bon masur vicia sp. 2 2 4 6 4.26 6.36 5.55 4 karim et al. total 47 47 72 87 100 100 100 100 clio @75 ml ha−1 bathua chenopodium album 2 2 2 5 4.65 4.90 3.92 4.90 durba cynadon dactylon 5 5 6 1 11.65 5.89 11.76 5.89 anguli digitaria sanguinalis 0 0 0 0 0 9.80 0 9.80 helencha jussica repens 6 6 8 6 13.95 5.89 15.68 5.89 hatishur heliotropium indicum 2 2 3 0 4.65 3.90 5.89 3.90 shama echinochloa crusgalli 10 10 8 12 23.25 28.43 15.68 28.43 bangchora 4 4 7 0 9.30 9.80 13.72 9.80 swetlomy gnaphalium japonicum 0 0 mutha cyperus rotundus 2 2 3 11 4.65 7.85 5.89 7.85 shaknote amaranthus viridis 3 3 3 3 6.98 5.89 5.89 5.89 gaicha paspalum commersonii 1 0 0 chapra eleusine indica 8 8 8 6 18.60 11.76 15.68 11.76 bon masur vicia sp. 1 1 3 2 2.32 5.89 5.89 5.89 total 43 43 51 94 100 100 100 100 clio @95 ml ha−1 bathua chenopodium album 1 1 2 5 4.55 2.74 6.90 4.90 durba cyradon dactylon 1 1 3 1 4.55 19.18 10.34 5.89 anguli digitaria sanguinalis 0 4.11 9.80 helencha jussica repens 5 5 3 6 22.72 4.11 10.34 5.89 hatishur heliotropium indicum 2 0 1.37 6.90 3.90 shama echinochloa crusgalli 3 3 5 12 13.63 34.25 17.24 28.43 bangchora 1 1 0 4.55 4.11 9.80 swetlomy gnaphalium japonicum 2 0 6.90 0 mutha cyperus rotundus 6 6 5 11 27.27 4.11 17.24 7.85 shaknote amaranthus viridis 4 4 3 18.18 1.37 5.89 gaicha paspalum commersonii 1 2.74 0 chapra eleusine indica 5 6 21.91 17.24 11.76 bon masur vicia sp. 1 1 2 2 4.55 6.90 5.89 total 22 22 29 101 100 100 100 100 clio @115 ml ha−1 bathua chenopodium album 3 2 4.90 10.00 2.74 durba cynadon dactylon 2 5 5.89 6.67 19.18 anguli digitaria sanguinalis 1 1 1 0 4.54 9.80 3.33 4.11 helencha jussica repens 11 11 8 6 50.00 5.89 26.66 4.11 hatishur heliotropium indicum 1 1 2 2 4.54 3.90 6.67 1.37 shama echinochloa crusgalli 10 28.43 34.25 determination of different doses of herbicide to control weeds in maize field 5 bangchora 4 4 3 4 18.19 9.80 10.00 4.11 swetlomy gnaphalium japonicum 1 1 2 4.54 0 6.67 0 mutha cyperus rotundus 3 2 7.85 10.00 4.11 shaknote amaranthus viridis 4 4 3 18.19 5.89 1.37 gaicha paspalum commersonii 0 2.74 chapra eleusine indica 6 8 11.76 20.00 21.91 bon masur vicia sp. 1 5.89 total 22 22 30 64 100 100 100 100 no weeding bathua chenopodium album 5 5 16 2 4.90 12.50 5.45 4.90 durba cyradon dactylon 6 6 7 5 5.89 2.78 6.36 5.89 anguli digitaria sanguinalis 10 10 16 0 9.80 4.17 14.55 9.80 helencha jussica repens 6 6 8 6 5.89 16.67 7.28 5.89 hatishur heliotropium indicum 4 4 7 2 3.90 4.17 6.36 3.90 shama echinochloa crusgalli 29 29 25 10 28.43 12.50 22.73 28.43 bangchora 10 10 4 9.80 2.78 9.80 swetlomy gnaphalium japonicum 0 0 4 0 1.81 0 mutha cyperus rotundus 8 8 12 2 7.85 19.44 10.91 7.85 shaknote amaranthus viridis 6 6 8 3 5.89 9.72 7.28 5.89 gaicha paspalum commersonii 0 0 1 0 4.17 0.91 0 chapra eleusine indica 12 12 13 8 11.76 5.55 10 11.76 bon masur vicia sp. 6 6 7 1 5.89 5.55 6.36 5.89 total 102 102 124 122 100 100 100 100 weed dry matter weight was significantly varied in different treatments. the highest dry weight of weeds at 25 das (14.15 g m−2) and (15.16 gm m−2) and at 45 das (44.31 g m−2) and (48.37 gm m−2), respectively in kharif-1, 2017 and rabi 2017-18 were found in control plot whereas the lowest in spraying of clio @115 ml ha−1 both at 25 and 45 das (table 2). table 2. dry weight of weeds and weed control efficiency in maize field at 25 das and 45 das as affected by different doses of clio treatments at 25 das at 45 das weed dry weight (gm m−2) weed control efficiency (%) weed dry weight (gm m−2) weed control efficiency (%) kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 t1 7.75 8.76 45.22 55.24 19.95 23.94 54.98 57.92 t2 4.10 5.11 71.02 81.02 16.56 18.50 62.67 68.62 t3 3.15 4.16 77.73 75.73 11.56 13.44 74.16 77.17 t4 2.20 3.21 84.45 89.47 8.85 8.84 80.03 88.14 t5 2.13 3.14 84.95 89.95 8.65 8.58 80.48 89.45 t6 14.15 15.16 44.31 48.37 t1= clio @35 ml ha−1, t2=clio @55 ml ha−1, t3= clio @75 ml ha−1, t4= clio @95 ml ha−1, t5= clio @115 ml ha−1, t6= no weeding 6 karim et al. the results corroborate with previous investigation (mondal et al., 2015, paul et al., 2015a, paul et al., 2015c, paul et al., 2017). the maximum wce over control both at 25 das (84.95% in kharif-1, 2017 and 89.95% in rabi 2017-18) and at 45 das (80.48% in kharif-1, 2017 and 89.45% in rabi 2017-18) respectively in spraying of clio @115 ml ha−1 (table 2). the maximum grain yield both in kharif-1, 2017(9.77 t ha−1) and rabi 2017-18(9.51 t ha−1) was found in spraying of clio @115 ml ha−1 which was statistically identical with spraying of clio @ 75 ml ha−1 and 95 ml ha−1 and lowest in no weeding (table 3). table 3. yield and yield contributing characters of maize as affected by different weed management methods t1= clio @35 ml ha−1, t2=clio @55 ml ha−1, t3= clio @75 ml ha−1, t4= clio @95 ml ha−1, t5= clio @115 ml ha−1, t6= no weeding the maximum benefit–cost ratio (mbcr) in kharif-1, 2017 (2.28) was obtained from clio @75 ml ha−1 which closely followed by clio @95 ml ha−1 of same mbcr but in rabi 201718 (2.41) both performed similar with spraying of clio @75 ml ha−1 followed by @95 ml ha−1 and lowest in no weeding (table 4). table 4. cost and benefit analysis of maize as influenced by different weed control management practice price: 15 tk kg−1. t1= clio @35 ml ha−1, t2=clio @55 ml ha−1, t3= clio @75 ml ha−1, t4= clio @95 ml ha−1, t5= clio @115 ml ha−1, t6= no weeding, mbcr = maximum benefit–cost ratio treatments plant height (cm) cob length (cm) cob diameter (cm) 1000-grains weight (gm) grain yield (t ha−1) kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 t1 236.3 248.7 21.13 25.12 4.58 4.67 391.8 387.5 8.35 8.52 t2 219.4 248.4 20.20 18.34 4.87 4.75 295.5 312.1 8.45 8.77 t3 224.2 226.3 17.86 21.44 5.46 5.57 292.6 324.7 8.62 8.24 t4 248.4 236.8 21.43 22.12 4.47 4.82 397.7 392.8 9.56 9.44 t5 212.3 224.2 18.33 20.21 4.85 4.79 324.1 295.5 9.77 9.51 t6 226.3 235.4 17.67 21.13 5.11 5.44 312.1 292.7 4.25 4.37 cv (%) 14.56 13.45 14.44 8.59 32.72 21.35 13.76 13.92 12.98 16.22 lsd (0.05) 3.76 4.22 3.97 3.97 2.95 4.21 4.57 4.25 2.97 3.11 treatments gross return (tk ha−1) total variable cost (tk ha−1) gross margin (tk ha−1) mbcr kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 kharif-1, 2017 rabi 2017-18 t1 93,424 99,455 80,700 80,700 12,724 18,755 2.16 2.23 t2 93,280 1,09,512 80,900 80,900 12,380 28,612 2.15 2.35 t3 1,03,880 1,13,896 81,200 81,200 22,680 32,696 2.28 2.40 t4 1,04,002 1,14,580 81,400 81,400 22,602 33,180 2.28 2.41 t5 1,06,070 1,16,373 83,828 83,828 22,242 32,545 2.27 2.39 t6 83,812 89,805 79,900 79,900 3,912 9,905 2.05 2.12 determination of different doses of herbicide to control weeds in maize field 7 conclusion chemical weed control technique is always prioritized first to the farmers due to its’ quick response and effective weed control efficacy. however, selection of an optimized dose for each and every herbicide is crucial considering its’ effectivity and eco-toxicological aspect. a chemical herbicide named clio was used to finalize an optimum dosage for weed control in maize field. the herbicide clio contains a new active ingredient named topramezone, a new subclass of the hppd-inhibiting herbicide. as a result, the possibility of adverse effect of this herbicide is lower than other herbicides. from the experimental results and findings, it might be concluded that clio has effective weed control efficacy on different weed species in maize fields. application of clio @ 95 ml ha−1 at 10 das of maize is economically profitable and it needs further trials to investigate eco-toxicological consequences to environment and living organisms after application. references ahmed, m., s. ishtiaque, m.m.r. sarker, a.s.m.m.r. khan, a.k. choudhury, m.k. hasan, f. hossain, s.k. paul, and m.u. islam. 2016. hybrid maize and chilli intercropping in the hilly areas of bandarban. bangladesh agron.j. 19(1): 45-48. hajong, p., s. mondal, d. saha, s. ishtiaque and s. paul. 2015. an economic study on panikachu production in jessore district. j. sylhet agril. univ. 2(1): 137-141. hajong, p., s. mondal, b. sikder, s. paul and d. saha. 2016. existing value chain assessment of date palm is selected areas of greater jessore districts. j. sylhet agril. univ. 3(1): 53-58. haque, m.m. 2017. allelopathic effect of sorghum plants parts water extract to control weeds in wheat field. haya saudi j. life sci. 2(1): 6-9. khan, m., j. chowdhury, m. razzaque, m. ali, s. paul and m. aziz. 2016. dry matter production and seed yield of soybean as affected by post-flowering salinity and water stress. bangladesh agron. j. 19(2): 21-27. kobir, m.s., m.o. ali, m. j. hossain, m.s. alam, s. paul, p. hajong and m.h. rahman. 2021. growth and yield of chickpea as affected by detopping time and height. bangladesh agron. j. 24(2): 109-113. kobir, m.s., m.r. rahman, a.m. islam, s. paul, m.m. islam, m.n. farid and p. hajong. 2019. yield performance of some maize varieties as influenced by irrigation management at different growth stages. res. agric., livest. fish. 6(1): 57-67. jahan, m.a.h.s. 2014. effect of different weed control methods in wheat. research report of wheat research centre. pp. 42-46. mondal, h., s. mazumder, s. roy, t. mujahidi and s. paul. 2015. growth, yield and quality of wheat varities as affected by different levels of nitrogen. bangladesh agron. j.18(1): 89-98. oerke, e. c. 2006. crop losses to pests. agric. sci.144(1): 31-43. paul, s.k., s. mazumder, s. mondal, s.k. roy and s. kundu. 2015a. intercropping coriander with brinjal forbrinjal fruit and shoot borer insect suppression. world j. agric. res. 11(5): 303-306. paul, s.k., s. mazumder, s. mondal, s.k. roy and s. kundu 2015b. intercropping coriander with chickpea for pod borer insect suppression. world j. agric. sci. 11(5): 307-310. paul, s.k., s. mazumder, t.a. mujahidi, s.k. roy and s. kundu 2015c. optimization of herbicide teana 9 ec dose for controlling weeds in brinjal. bangladesh agron. j. 18: 113-119. paul, s.k., y. xi., p. sanderson and r. naidu. 2023. investigation of the physicochemical properties of amine-modified organoclays influenced by system ph and their potential to adsorb anionic herbicide. geoderma, 436, 116560. paul, s.k., s. akther, t.a. mujahidi. and s. kundu. 2017. effect of different doses of herbicide (metro 70wg) on weed control in maize field. bangladesh agron. j. 20(1): 109-111. paul, s.k., s. mazumder. and r. naidu. 2024a. herbicidal weed management practices: history and future prospects of nanotechnology in an eco-friendly crop production system. heliyon.10(5): e26527 paul, s.k. and r. naidu. 2022. layered aluminosilicate nanoskeletons: the structure and properties of nanoherbicide formulations. adva. agron. 175: 301-345. 8 karim et al. paul, s.k., m. nuruzzaman., t.c., and r. naidu. 2019. aluminosilicate nano-skeleton to firm the structure and properties of nano-herbicide formulations. in: proceedings of the 8th international contamination site remediation conference. pp. 302-303. paul, s.k., y. xi, p. sanderson, a.k. deb, m.r. islam and r. naidu. 2023. investigation of herbicide sorption-desorption using pristine and organoclays to explore the potential carriers for controlled release formulation. chemosphere, 337, 139335. paul, s.k., y. xi, s. peter. and r. naidu. 2024b. controlled release herbicide formulation for effective weed control efficacy. sci. rep. 14(1): 4216. paul, s.k. and p.s. xy. 2022. rn controlled release formulation of herbicide: a safe technique for effective weed management practice. in: proceedings of the international cleanup conference. pp. 462-463. bangladesh agron. j. 2021, 24(2): 21-30 evaluation of resistant genotype against brinjal shoot and fruit borer (leucinodesorbonalis guenee) m.a. mannan, s. ferdousi, m.m. kamal and s. das agrotechnology discipline, khulna university, khulna-9208, bangladesh corresponding e-mail: mannanku@gmail.com (received: 31july 2021, accepted: 12 september 2021) keywords: bsfb, infestation, brinjal, genotypes, resistant, varieties abstract brinjal shoot and fruit borer (bsfb), leucinodesorbonalis guenee, is a devastating pest of brinjal (solanummelongena l.) in all brinjal growing countries across the globe. ten genotypes of brinjal were evaluated against the pest in experimental field of khulna university, bangladesh following arandomized block design with three replications. the genotypes were bari hybrid begun-2, bari hybrid begun-4, bari bt-4, begun-4, bari begun-9 and bari begun-10, local cultivar-1, local cultivar-2, local cultivar3, local cultivar-4 and bari begun-4among the ten brinjal genotypes, reduced shoot and fruit infestation were recorded in local cultivar-1 and bari begun 2. on degree of infestation, bari hybrid bt begun 4 appeared to be resistant while rest of the genotypes were susceptible or highly susceptible. volume index was documented to be high in bari hybrid begun 4 and low in local cultivar 3, while shape index was high in cultivar 2 and low in bari hybrid begun 4 and bari begun-10. bari hybrid begun 4 possessed greater meso and pericarp thickness although those were not resistant. above all, using resistant genotypes of bari hybrid bt begun 4 may be considered as a last resort inan optimized ipm package to ensure maximum brinjal productivity. introduction in bangladesh, brinjal is one of the most popular and favoured vegetables which is grown throughout the country.it is commercially cultivated in jessore, rajshahi, narsinghdi, dhaka, comilla, and bogra districts. it is grown in both rabi and kharif season in bangladesh. rabi brinjal has been cultivated over 82000 acres of land and the total production was 360000 tons and kharif brinjal has been cultivated over 47000 acres of land and the total production was 170000 tons (bbs, 2020). regarding nutritional value, brinjal possesses a very low caloric value but high content of vitamins, minerals, and bioactive compounds for human health (raigón et al., 2008; plazas et al., 2014b; docimo et al., 2016). brinjal is quite susceptible to several environmental stresses, especially acute temperature, drought, salinity, and inadequate moisture stresses (kalloo, 1993) which affect the growth and development of the plant. it has a relatively longer growth period and life span, brinjal is more vulnerable than other vegetable crops to a broad range of plant diseases, pests, nematodes, and weeds. the major handicap to the sustainable productivity of brinjal in bangladesh is the high incidence of insect pests. in total 9 species of insects belonging to 7 families of 4 orders have been reported as a pest in brinjal field e.g. epilachna beetle (epilachnadodecastigma), jassid (amrascabiguttula), whitefly (bemisiatabaci), shoot and fruit borer (leucinodesorbonalis), rice bug (leptocorisaacuta), aphid (aphis gossypii), thrips (thripshawaiiensis) and leaf hopper (amrascadevastans) (amin et al., 2018). among them, brinjal shoot and fruit borer (bsfb) is reported to induce about 16 and 70% damage to shoots and fruits, respectively (kar et al., 2020). it is recognized as the most damaging pest of brinjal 22 mamman et al. (taylo et al., 2016). it scales down the productivity as well as the quality of marketable fruits of brinjal. the larval stage of the pest is mainly catastrophic and can cause severe damage to fruits and shoots. newly hatched larvae invade the vascular bundle of the plant and hit translocation of food and nutrients towards shoots. approximately 4-6 healthy fruits can be destroyed because of the attack of a single larvae (jayaraj and manisegaran, 2010). because of the concealed mode of life, it is the most serious pest of brinjal (sardana et al., 2004). this insect pest is accountable for 70-92% of yield loss (chakraborti and sarkar, 2011). there are several measures to mitigate this including spraying of chemical insecticides, application of botanical pesticides, adopting ipm technologies, using resistant varieties and so on.. a survey report revealed that 98% of bangladeshi farmers are dependent entirely on spraying insecticides to control bfsb (karim, 2004). so, it is a burning question to identify and use of most effective resistant varieties, proper chemical insecticide and effective botanical pesticides to ensure eco-friendly pest management under ipm technology. materials and methods the present study was carried out at the experimental field of the germplasm centre of khulna university, bangladesh during september 2020 to may, 2021. the study area is situated at 24.09° north latitude and 90.26° east longitudes with an elevation of 8.4 meter from the sea level.the climatic condition of khulna university has unimodal rainfall pattern; most of the rainfalloccurs during the months of may to september. the average rainfall is usually higherthan 200 mm during november to march. the warmer months are april, may and june with mean maximum temperature of 31-34°c and the cold months are november, december and january when the temperature ranges from 1019°c. the area belongs to the ganges flood plain (aez-13), clay loam in texture having low organic matter (1.12%) moderately slow permeability and deficient in nitrogen, potassium and sulphur. the soil is mostly alkaline and somewhat saline in nature having ph 6.5 to 8.5. brinjal seeds of 10 varieties viz. bari hybrid begun-2, bari hybrid begun-4, bari bt-4, begun-4, bari begun-9 and bari begun-10, local cultivar-1, local cultivar-2, local cultivar-3, and local cultivar-4 and bari begun-4 which were collected from horticulture division, bangladesh agricultural research institute (bari), joydebpur, gazipur, the local ones from the farmers of the khulna region. a small seedbed measuring 5 m x 1 m was prepared and seeds were sown there. standard seedling raising practice was followed. the plots were lightly irrigated regularly for ensuring proper development of the seedlings. the seedbed was mulched for ensuring seed germination, proper growth and development of the seedlings. thirty-six day-old (3/4 leaf stage) healthy seedlings were transplanted in 50 cm apart in 2.0 meter ×2.5 size plots in rows in three replications laid out inrcbd design with 3 replications. each row separated by 50 cm which contained 16 plants of each variety. after transplanting light irrigation was given to each pit. dead or damaged seedlings were replaced immediately by new ones from the stock. supple mentary irrigation was applied at an interval of 2-3 days. propping of each plant using bamboo sticks (l m height) was done for providing extra support to avoid lodging of theplants. weeding andmulching were given whenever necessary. cow dung @ 15 tons, 250, 150 and 125 kg of urea, tsp and mop, respectively per hectare. the half of cow dung and tsp were applied as basal dose during land preparation. the remaining cow dung, tsp and, onethird of mop were applied in the pits at transplantation of brinjal seedlings. the entire dose of urea and the rest of mopwere applied as top dressing. the first top dressing of urea (one third) was made at 15 days after transplanting. one third of urea and onethird of mop at the time of flower initiation and rest of urea and mop at the time of fruit development. the incidence of leucinodesorbonalis guenee was recorded at seven days intervals starting from the evaluation of resistant genotype against brinjal 23 first appearance of shoot and fruit borer after transplanting the brinjal crop and continued till the harvesting of the crop. the infestation and intensity of leucinodesorbonalis guenee on young plants were recorded by counting infected and healthy shoots on randomly counted at each picking (weekly). damaged (%) on shoot and fruit was calculated by recording the number of total and infestedshoot and fruit. the observation was converted into percentage and germplasm were classified according to the scoring pattern adopted. the germplasm was categorized as highly resistance (%), resistant (0-15%), moderately resistant (16-30%), susceptible (31-45%) and highly susceptible (above 46%) respectively. the fruit characters studies include length, diameter, shape and volume index, length of peripheral seed-ring and seedless area, thickness of mesocarp and pericarp. numbers of fruits per plant were recorded from 5 randomly selected plants from each plot.random samples of fruits of 5 plants (10 fruits from each plant) were taken from each plot... for calculating various parameters, following formula were used shape index = length fruit/fruit diameter, volume index = length fruit x fruit diameter, rlps = length of peripheral seed ring/total length of fruit, rlsa = length of seed less area/total length of fruit, where, rlps = ratio of length of peripheral seed ring and rlsa = ratio of length of seedless area. total number of infested shoots and fruitsdue to the infestationby the natural population of bsfb from randomly selected 5 plants/replication were counted and recorded at every 10 days interval from 30 days after transplanting (dat). infestation percentage of bsfb on shoots and fruits were calculated.relative resistance of theplants against bsfb was estimated on the basis of shoot and fruit damage severity.those pest damage grading were done on this basis the grading index followed by subbratnam and butani(1981) (table 1). tables 1. pest damage grading due to bsfb attack on shoots and fruits of brinjal (subbratnam and butani, 1981). grading percent shoot infestation percent fruit infestation highly resistant (hr) < 1.0% < 5.0% resistant (r) 1.1-2.0% 5.1-15.0% moderately resistant (mr) 2.1-3.0% 15.1-25.0% susceptible (s) 3.1-5.0% 25.1-40.0% highly susceptible (fis) > 5.0% > 40.0% bsfb= brinjal shoot and fruit borer the critical difference was calculated for the comparison of different germplasm of brinjal. simple correlation (r)between shoot and fruit borer leucinonedsorbonalis guen. and fruit infestation of different germplasm of brinjal and fruit characters. the quantitative data for the character were statically analyzed for analysis of variance and the means were compared by dmrt as well as the correlation between these characters and the degree of fruitinfestation (gomez and gomez, 1984). results and discussion brinjal cultivar-2 gave the tallest (85.83 cm) and it was the shortest in bari begun-4 (plant height 45.83 cm) in length among the tested cultivars (table 2). plants of other varieties were attended medium height. the highest number of leaves were also obtained from local cultivar-4. 24 mamman et al. length and breadth of the leaves of bari hybrid begun-2 and bari hybrid begun-4 were the highest than the other ones.average number of shoots and infested shoot were observed in bari begun-10 (39.33 and 16.67 plant-1, respectively). table 2. growth parameter of the varieties and shoot infestation variety plant height (cm) average no. of leaves plant-1 average length of leaf (cm) average breadth of leaf (cm) no of shoots plant-1 no. of infested shoots plant-1 bari hybrid begun-2 62.50b 53.33bc 33.00a 18.33ab 30.67 13.67abc bari hybrid begun-4 55.33bc 50.33bcd 31.00ab 19.83a 28.33 11.00bc bari btbegun-4 57.00bc 45.33bcd 28.67bc 13.00bcd 36.00 14.00abc bari begun-9 53.17bc 44.00cd 26.33cd 14.67abcd 29.00 9.00c bari begun-10 55.23bc 39.89d 30.67ab 19.33a 39.33 16.67a local cultivar-1 51.17bc 57.17bcd 28.50bc 17.00abc 34.67 12.00abc local cultivar-2 59.17bc 52.67bcd 30.17abc 13.17bcd 31.67 16.33ab local cultivar-3 49.67bc 58.00b 22.00e 12.00cd 31.67 12.00abc local cultivar-4 85.83a 73.67a 24.33de 11.00d 26.00 11.33abc bari begun-4 45.83c 46.50bcd 27.58bcd 13.17bcd 30.67 16.00ab lsd (0.05) 13.68 13.26 4.10 5.87 5.38 data in a column with same letter do not differ significant by lsd test fruit characteristics are consideredas the important ones forresistant breeding and fruit yield. there were significant differences among the brinjal varieties in respect of yield contributing character and yield (table 3). the highest number of flowers and fruits were found in local cultivar-4 (106 and 32, respectively) and those were the lowest in bari begun-4 (44.33 and 9.00, respectively). the highest infested fruits and larvae were obtained from bari hybrid begun-2 and bari hybrid begun-4 (21.67 and 13.33, respectively). average fruit weight per plant was the highest (9.53 kg) and weight of individual fru it in bari bt begun-4 (273.63 g). average yield was recorded from local cultivar -3 (165.00 t/ha) followed by bari bt begun-4 (99.23 t/ha). table 3. yield contributing parameters and fruit yield of the varieties and number of larvae variety no. of flowers plant-1 total no. of fruits plant-1 no. of infested fruit plant-1 no. of larvae plant-1 average fruit weight plant-1 (kg) weight of individual fruit (g) fruit yield (t/ha) bari hybrid begun-2 56.67b 27.00ab 21.67a 9.67ab 7.23bcd 133.67d 115.42b bari hybrid begun-4 73.67ab 23.67abc 17.67ab 13.33a 7.97ab 94.47e 71.45cd bari btbegun-4 6300ab 21.33bcd 1.00e 2.00e 6.27bcd 273.63a 99.23bc bari begun-9 67.00ab 14.33de 5.33de 3.67de 5.23d 74.50f 33.84d bari begun-10 71.67ab 15.33cde 8.00cde 5.00cde 5.53d 79.23f 38.69d local cultivar-1 75.33ab 20.67bcd 1467abc 4.00de 7.56abc 136.40d 90.23bc local cultivar-2 80.67ab 17.00cde 13.00bcd 6.00bcde 6.93bcd 131.47d 71.55cd evaluation of resistant genotype against brinjal 25 local cultivar-3 86.00ab 27.33ab 20.67ab 7.67bcd 9.53a 188.27c 165.00a local cultivar-4 106.00a 32.00a 18.33ab 9.00bc 7.73ab 64.50g 66.24cd bari begun-4 44.33b 9.00e 4.00e 2.33e 5.60cd 206.34b 59.68cd lsd (0.05) 44.37 9.16 7.99 4.28 2.03 6.23 41.22 data in a column with same letter do not differ significantly by lsd test there were significant variations among the varieties in respect of shoot infestation (table 4). infestation percent of shoot by bsfb was recorded in brinjal germplasm, ranged from 32.33 to 52.33%. the maximum shoot infestation (52.33%) was found in bari begun-4, which was statistically similar to local cultivar-2 (51.40%) followed by local cultivar-4 (43.67%). the lowest shoot infestation was recorded from local cultivar-1 (32.33%). infestation percent of fruit borer was recorded in brinjal germplasm, ranged from 4.20 to 80.60. minimum mean infestation in fruits was found in bari btbegun-4 (4.20%) while maximum in bari hybrid begun-2 (80.60). mean percent infestation of shoot and fruit borer in fruits has been presented in table 4. comparable range of fruit infestation was 20.23 to 45.61% reported by jat (2003), though they used different set of varieties/cultivars in their experiment. kumar and shukla (2002) was found 33 to 53% damage of fruits in 12 different cultivars of brinjal. similarly, ashoke and abhishek (2002) while evaluating 12 brinjal cultivars infield conditions reported 33.6553.02% fruit infestation of l. orbonalis larvae. conversely, chaudhary and sharma (2000) found very low attack of brinjal shoot and fruit borer (2.88-5.64%) during screening of nine genotypes of brinjal. general equilibrium position of shoot infestation of different entries of brinjal was calculated on the basis of their infestation, which is varied between 9.0 to 52.33% shoot infestations (table 4and 5). only one genotype of brinjalviz, rari bt begun-4 had 9.00% shoot infestation showing tolerance. four entries like, bari hybrid begun-4, bari begun-9, local cultivar-1 and local cultivar-4 weresusceptibleagainst this pest and other 5 varieties namely bari hybrid begun-2, bari hybrid begun-4 bari begun-10, local cultivar-2 and local cultivar-3 were categorized as highly susceptible genotype, respectively (table 5). none of the varieties were found moderately tolerant and resistance againstfruit borer. another categorization of tested entries against shoot and fruit borer done on the basis of rank allotted to the shoot as well as fruit infestation. table 4. categorization of different germplasm of brinjal by ranking method based on shoot & fruit infestation sl. no. germplasm shoot infestation (%) rank fruit infestation (%) rank 1 bari hybrid begun-2 43.27bc hs 80.60a hs 2 bari hybrid begun-4 39.13cd s 75.60a hs 3 bari btbegun-4 9.00cde t 4.2c t 4 bari begun-9 34.50ef s 34.20bc s 5 bari begun-10 42.50bc hs 53.90abc hs 6 local cultivar-1 32.33f s 71.93ab hs 7 local cultivar-2 51.40a hs 55.23abc hs 8 local cultivar-3 36.67def s 72.77ab hs 9 local cultivar-4 43.67b hs 57.50abc hs 10 bari begun-4 52.33a hs 45.47abc hs table 5. categories of the brinjal varieties of the present study based on average rank of shoot and fruit infestation sl. no. category range of infestation name of germplasm based on shoot infestation fruit infestation 26 mamman et al. 1 highly resistance (hr) ‹ 5% 0 2 resistance 5.1-15 bari bt begun -4 bari bt begun -4 3 moderately resistance (mr) 15.1-25% 0 0 4 susceptible(s) 25.140.0% bari hybrid begun-4, bari begun-9, local cultivar-1 and local cultivar-3 bari begun-9 5 highly susceptible (hs) above 40% bari hybrid begun-2, bari begun-10, local cultivar-2 and local cultivar-4 bari hybrid begun-2, bari hybrid begun-4, bari begun-10, local cultivar-1 and local cultivar2 local cultivar-3 and local cultivar-4 the variationindegreeofinfestationofanypest is the combined effect of genetic architecture of crop variety and abiotic factor. the germplasm/variety cited above are not resistant/moderately resistant to this pest except the genetically modified variety bari bt begun-4. so, it can be mentioned that breeding program of thiscrop is necessary for development of resistant variety of pure line. the mean length of fruit ranged 6.00 to 26.67 cm (table 6). only one genotype viz. loval cultivar-2 were short fruited (fruit length 6 cm); while 5 genotypes like bari begun-4, bari hybrid begun-2, bari hybrid begun-4, bari bt begun-4 and local cultivar-4 hadmedium length of fruits (fruit length 7-10 cm). other four genotype i.e. bari begun-9, bari begun-10. local cultivar1 and local cultivar-3 were having extra-long fruits (fruit length 12-22 cm). there was positive non-significant correlation between the length of fruit and the degree of fruit infestation (table 6). the fruit diameter (fd) was between the ranges of 2.70 to 9.10cm (table 6). two genotypes were in the range of 0 to 4 cm diameters viz, bari begun-9 (2.70 cm) and bari begun-10 (2.76 cm). three varieties viz. local cultivar-1 (5.66 cm), local cultivar-2 (5.90 cm) and local cultivar-4 (4.73) was foundmedium diameter (4 to 6 cm) and the other 5 genotypes viz, bari hybrid begun-2 (6.53 cm), bari hybrid begun-4 (7.78 cm), bari bt begun-4 (9.10cm). the shape index varied from 1.60 to 2.32). six genotypes were grouped into round (shape index 1.6021.86 cm), which were local cultivar-3 (1.85), bari begun-9 (1.86), bari hybrid begun-2 (1.81), local cultivar-1 (1.78), bari hybrid begun-4 (1.60) and bari begun-10 (1.60). four varieties were grouped to oval to longish (shape index 2.10 to 2.32 cm) viz. bari btbegun-4 (2.21), local cultivar2 (2.32), local cultivar-4 (2.24) and bari begun-4 (2.10). the ratio of the length of peripheral seed ring to total length of the fruit (rlps) indicating the degree of mechanical seed barrier to the entry of borer varied from (0.132 to 0.641) as given in table 6. the less rlps (0.132 to 0.189) was observed in five genotypes, which were bari hybrid begun-4 (0.132), bari begun-4 (0.137), bari hybrid begun-2(0.140), bari bt begun-4 (0.163) and local cultiva-2 (0.189). the medium rlps (0.203 to 0.348) was found in four varieties, which were local cultivar-1 (0.203), local cultivar-3 (0.249), local cultivar-4 (0.300) and bari begun-10 (0.348. thehigh rlps (above 0.500) was recorded from only one variety named bari begun-9 (0.641). the ratioof length of seedless area to the total length of fruit indicating the pulpiness of fruit ranged 0.060 to 0.198. table 6. characters of brinjal fruit in relation to shoot and fruit borer incidence s. n. germplasm fruit length (cm) fruit diameter (cm) shape index (l/d) volume index (lxd) rlps rlsa thickness of fruit infestation (%) pericarp mesocarp 1 bari hybrid begun-2 9.54b 6.53cd 1.81bc 605.00a 0.140d 0.117bc 0.47ab 8.98abc 80.60a 2 bari hybrid 7.78b 6.07de 1.60c 614.83a 0.132d 0.156ab 0.55ab 8.86abc 75.60a evaluation of resistant genotype against brinjal 27 begun-4 3 bari btbegun-4 10.61b 9.10a 2.21ab 373.00bc 0.163cd 0.195a 0.61a 10.78a 4.20c 4 bari begun-9 19.78ab 2.70g 1.86abc 392.67abc 0.641a 0.061c 0.23c 10.01ab 34.20bc 5 bari begun-10 21.39ab 2.76g 1.60c 592.00ab 0.347b 0.116bc 0.43b 10.82a 53.90abc 6 local cultivar-1 13.44ab 5.66e 1.78bc 507.25ab 0.203bcd 0.154ab 0.48ab 7.39abcd 71.93ab 7 local cultivar-2 6.00b 5.90de 2.32a 400.83abc 0.189cd 0.156ab 0.52ab 2.78bcd 55.23abc 8 local cultivar-3 26.67a 7.29bc 1.85abc 264.00c 0.249bcd 0.198a 0.51ab 1.87cd 72.77ab 9 local cultivar-4 9.70b 4.73f 2.24ab 268.33c 0.300bc 0.146ab 0.43b 2.43cd 57.50abc 10 bari begun-4 8.06b 7.81b 2.10ab 367.58bc 0.137d 0.188a 0.56ab 1.83cd 45.47abc lsd value 13.98 0.87 0.46 224.56 0.155 0.066 0.17 7.37 35.98 the pericarp thickness of fruit varied from (2.33 to 6.11 cm) (table 4.5). only one genotype was found with medium pericarp (0.15 to 0.35 cm), which was bari begun-9 (0.23 cm). the other 9 varieties had broader pericarp (0.47 – 0.56). the thickness of mesocarp varied1.83 to 10.82 cm (table 6). the narrow mesocarp (1 to 2.78 cm) was found in four genotypes i.e. local cultivar-2 (2.78 cm), local cultivar-3 (1.87 cm), local cultivar-4 (2.43 cm), bari begun-4 (1.83 cm). the medium mesocarp was measured from three varieties ranged (7.0 to 8.98 cm) viz. bari hybrid begun-2 (8.98 cm), bari hybrid begun-4 (8.86 cm) and local cultivar-1(7.39 cm). the broader mesocarp was calculated from three varieties ranged above 10.0 cm, which were bari bt begun-4 (10.78 cm), bari begun-9 (10.01 cm) and bari begun-10 (10.82 cm). correlation matrix between fruit infestation and fruit length, fruit diameter, shape index, volume index, rlps (ratio of length of pericarpal seed ring), rlsa (ratio of length of seedless area) and thickness of pericarp and mesocarp was develop to asses of effect of fruit character on the infestation of fruit borer (table 7). it was observed that shape index, rlsa and pericarp has significant negative association with fruity infestation (r = -0.334, -0.365 and -0.384, respectively), whereas thickness of mesocarp was positively significantly correlated (r = 0.445). other factors like fruit length, fruit diameter, volume index and rlps had non-significant impact in fruit infestation. however, the shape index is the ratio of fruit length and fruit diameter; fruit length had negative association with fruit infestation, while fruit diameter was associated positively. this indicated that enhancement in fruit length reduces the fruit infestationwhereas the fruit diameter increases the infestation (table 7). table 7. relationship of fruit infestation with fruit characters in brinjal character fruit diameter shape index volume index rlps rlsa pericarp thickness mesocarp thickness fruit infestation fruit length 0.731** -0.334 0.850** -0.347 -0.281 0.128 0.518** -0.091 fruit diameter -0.861** 0.978** -0.124 -0.400* -0.114 0.858** 0.322 shape index -0.747** -0.041 0.356* 0.237 -0.810** -0.334 volume index -0.207 -0.383* -0.045 0.804** 0.260 rlps 0.667** -0.807** 0.318 0.350 rlsa 0.899** -0.785** -0.365* pericarp thickness -0.609** -0.384* mesocarp thickness 0.455* it can be summarized that long fruit with more thickness of mesocarp were having less infestation of fruit borer in brinjal crop. these investigations was corroborates with the findings ofmote, 1976)who reported that there were negative correlation of thickness of mesocarp and fruit infestation in brinjal. conclusion 28 mamman et al. it can be concluded from the present experiment that out of the 10 local cultivars and varieties of brinjal screened against shoot and fruit borer, none was found completely free from infestation of the shoot and fruit borer. however, the genetically modified brinjal variety bari bt bgun-4 was recorded lowest percent of shoot and fruit infestation(rating scale1) with highly resistant capacity and higher yield than remaining cultivars. acknowledgement the author are hereby gratefully acknowledge the khulna university research cell for providing fund to conduct the study properly. references amin, m. r., miah, m. s., rahman, h., nancy, n. p. and bhuiyan, m. k. a. 2018. functional and group abundance of insects on eggplant. ban. j.agri. res., 43(4), 647-653. ashoke k. and abhishek s. 2002. varietal preference of fruit and shoot borer, leucinodesorbonalis guen. onbrinjal. insect environ. 8(1):44. bbs. 2020. yearbook of agricultural statistics-2020 (vol. 31st series). bangladesh: bangladesh bureau of statistics (bbs). retrieved from http://bbs.portal.gov.bd/sites/default/files/files/bbs.portal.gov.bd/page/1b1eb817_9325_4354_a756 _3d18412203e2/2020-10-06-09-58-453f7e0a42348e05f0999979870ec 07b. pdf braga, p. c., lo scalzo, r., dal sasso, m., lattuada, n., greco, v. and fibiani, m. (2016). characterization and antioxidant activity of semi-purified extracts and pure delphinine-glycosides from eggplant peel (solanummelongena l.) and allied species. j. funct. foods 20, 411–421. doi: 10.1016/j.jff.2015.10.032 cao, g., sofic, e. and prior, r. l. 1996. antioxidant capacity of tea and common vegetables. j. agric. food chem. 44, 3426–3431. doi: 10.1021/jf9602535 chakraborti, s. and sarkar, p. 2011. management of leucindesorbonalis guenee on eggplants during the rainy season in india. plant protect. res. j. 51 (4), 325-328. chaudhary d.r. and sharma s.d. 2000. screening of some brinjal cultivars against bacterial wilt and fruit borer. agric. sci. digest.,20(2):129-130. daunay, m. c. and hazra, p. 2012. “eggplant,” in handbook of vegetables, eds k. v. peter and p. hazra (houston, tx: studium press), 257–322. docimo, t., francese, g., ruggiero, a., batelli, g., de palma, m. and bassolino, l. 2016. phenylpropanoids accumulation in eggplant fruit: characterization of biosynthetic genes and regulation by a myb transcription factor. front. plant sci. 6:1233. doi: 10.3389/fpls.2015.01233. fao. 2019. compare data. retrieved january 30, 2021, from faostat: http://www.fao.org/faostat/en/#compare gangopadhyay c, maity t.k. and mandal s.k. 1996. screening of brinjal germplasms against fruit and shoot borer, leucinodesorbonalis guen. environ. and ecol., 14:834-836. gomez, k. a., & gomez, a. a. 1984. statistical procedures for agricultural research. john wiley & sons. jatk.l. 2003. biophisical and biochemical factor of resistance in brinjal against leucinodesorbanalis guen. indian journal of entomology,65(2):252-259. jayaraj, j. and manisegaran, s., 2010. management of fruit and shoot borer in brinjal. the hindu sci-tech. agri. college and res. inst. madurai. http://bbs.portal.gov.bd/sites/default/files/files/bbs.portal.gov.bd/page/1b1eb817_9325_4354_a756_3d18412203e2/2020-10-06-09-58-453f7e0a42348e05f0999979870ec%2007b.%20pdf http://bbs.portal.gov.bd/sites/default/files/files/bbs.portal.gov.bd/page/1b1eb817_9325_4354_a756_3d18412203e2/2020-10-06-09-58-453f7e0a42348e05f0999979870ec%2007b.%20pdf evaluation of resistant genotype against brinjal 29 kalloo, g. (993) eggplant: solanummelongena l. genetic improvement of vegetable crops, 587-604. kar, d., kuanar, a., ray, a., gaur, m., pattanaik, b. and mishra, b. 2020. genetic diversity of brinjal fruit and shoot borer (bsfb) population of odisha, india. iranian journal of science and technology, transactions a: science, 1-10. karim a.n.m.r. 2004.ipm for vegetable crops: issues and technology developments in bangladesh. a keynote paper presented at the sixth biennial conference of bangladesh entomological society held at bari, joydebpur, gazipur, bangladesh, october 7, 2004; 2004. krishna t.m, lal o.p., srivastava y.n. 2001. extent of losses caused by shoot and fruit borer, leucinodesorbonalis guen., to promising varieties of brinjal, solanummelongena l. j entomol. res., 25(3):205-212. kumar a. and shukla a. 2002. varietal preference of fruit and shoot borer, leucinodeorbonalis guen. onbrinjal. insect environment. 2002;8(1):44. mennella, g., lo scalzo, r., fibiani, m., d'alessandro, a., francese, g., toppino, l., et al. 2012. chemical and bioactive quality traits during fruit ripening in eggplant (s. melongena l.) and allied species. j. agric. food chem. 60, 11821–11831. doi: 10.1021/jf3037424 naeem, m. y. andugur, s. 2019. nutritional content and health benefits of eggplant. turkish journal of agriculture-food science and technology, 7(sp3), 31-36. niño-medina, g., urías-orona, v., muy-rangel, m. d., & heredia, j. b. (2017). structure and content of phenolics in eggplant (solanummelongena)-a review. south african journal of botany, 111, 161169. plazas, m., andújar, i., vilanova, s., gramazio, p., herraiz, f. j. 2014a. conventional and phenomics characterization provides insight into the diversity and relationships of hypervariable scarlet (solanumaethiopicum l.) and gboma (s. macrocarpon l.) eggplant complexes. front. plant sci. 5:318. doi: 10.3389/fpls.2014.00318 plazas, m., andújar, i., vilanova, s., hurtado, m., gramazio, p., herraiz, f. j. (2013. breeding for chlorogenic acid content in eggplant: interest and prospects. not. bot. horti. agrobot. 41, 26–35. doi: 10.15835/nbha4119036 raigón, m. d., prohens, j., muñoz-falcón, j. e., and nuez, f. 2008. comparison of eggplant landraces and commercial varieties for fruit content of phenolics, minerals, dry matter and protein. j. food comp. anal. 21, 370–376. doi: 10.1016/j.jfca.2008.03.006. rashid, m.m. 1999.begun paribarer shabji. pp. 137 -154. in: shabji biggan(in bangla). 1sted. bangla academy, dhaka, bangladesh. 515 p. sardana h.p., arora s, singh d.k., kadu l.n. 2004. development and validation of adaptable integrated pest management in eggplant, solanummelongena l. in a farmers participatory approach. indian journal of plant protection. 2004; 32:123-128. schippers, r. r. 2000. african indigenous vegetables: an overview of the cultivated species. natural resources institute/acp-eu technical centre for agricultural and rural cooperation, chatham, uk. stommel, j. r., whitaker, b. d., haynes, k. g., and prohens, j. 2015. genotype × environment interactions in eggplant for fruit phenolic acid content. euphytica 205, 823–836. doi: 10.1007/s10681-0151415-2 taylo, l.d., sison m.l.j. and hautea d.m. 2016. use of artificial infestation for field bioefficacy assessment of bt eggplant against the eggplant fruit and shoot borer, leucinodesorbonalis guenee (lepidoptera: crambidae). philipp. agric. sci. 99:119-126. yadav d.s. andsharma mm. 2005. evaluation of brinjal varities foe their resistance against fruit and shoot 30 mamman et al. borer, leucinodesorbonalis guen. indian journal of entomology, (2):129-132. yadav ln, sharma j.k., yadav s.k. 2003. varietal screening of brinjal against fruit and shoot borer, leucinodesorbonalis guen. annals of agro bio research, 8(1):77-80. for calculating various parameters, following formula were used bangladesh agron. j. 2021, 24(2): 1-12 performance of two aman rice varieties using varying plant density in the northeastern region of bangladesh f. ahmed1, m.n. islam2 and m.h.m.b. bhuyan1 1citrus research station, bangladesh agricultural research institute, jaintapur, sylhet 3156, bangladesh 2departments of agronomy, sylhet agricultural university, tillagorh, sylhet-3100, bangladesh corresponding e-mail: faisal.ag.sau@gmail.com (received: 03june 2021, accepted: 29august 2021) keywords: aromatic rice, spacing, panicle, yield, harvest index abstract the experiment was conducted to assess the performance of two popular rice varieties with varying spacing at a farmer's field in darbost union of jaintapur upazila under the sylhet district of bangladesh during aman season 2016. two aman rice varieties (brri dhan34 and binadhan-17), and four levels of plant density (15×10 cm, 20×10 cm, 20×15 cm, and 25×15 cm) were tested in a factorial randomized complete block design (rcbd) with three replications. the results indicated that yield and yield attributes of rice differed significantly due to varieties, spacing, and their interaction. it was recorded that var. binadhan-17 showed maximum flag leaf length (34.33 cm), maximum number of filled grains m−2 (27855), maximum grain weight m−2 (654.58) contributed to increase grain yield (6.55 t ha−1) in closer spacing (20×10 cm), which ultimately increased grain yield. therefore, the results of the present study suggested that rice var. binadhan-17 could be transplanted at 20×10 cm spacing for getting maximum yield (6.55 t ha−1) in northeastern region of bangladesh. introduction in bangladesh, approximately 11.61 million hectares land is under rice cultivation and producing 36.28 million tons (bbs, 2019). in 2018-19, the country acquired a rice surplus of about 2 mt (bbs, 2019). therefore, exporting rice from the current surplus as well as maintaining the productivity and quality is a great challenge for the rice growers in the coming decades, where the high yielding could be an option. the aromatic rice is known for its quality, fragrance, and demand in the domestic as well as international markets (bajpai and singh, 2010). but the fact is that farmers preferred coarse and medium rice varieties, whereas a minimal land space is covered by the fine and aromatic rice varieties (bajpai and singh, 2010). due to a higher price, the aromatic rice is gaining popularity in bangladesh. some locally adapted varieties like chinigura, kalizira, and kataribhog, etc. are covering rice-growing areas. bangladesh rice research institute (brri) and bangladesh institute of nuclear agriculture (bina) has released some high yielder aromatic rice varieties like brri dhan34 and binadhan-17 for the aman season. although the average yield per unit area increased, but, there is a wide yield gap between farmers' fields and onstation research results. this yield gap could be attributed to either the endogenous drivers, like genetic makeup and agronomic practices (imade et al., 2015) or exogenous forces like climatic condition, which affects the genetic capability (lesk et al., 2016). 2 ahmed et al. some previous reports suggested that, a suitable variety is an important key to produce a higher return, together with a proper spacing, which plays a vital role in increasing growth development and yield of a specific rice variety to a great extent (rahman et al., 2007; thakur et al., 2009; bozorgi et al., 2011). a sufficient spacing increases the performance of individual plants, while improper spacing reduced yield up to 20-30% (irri, 1997). an optimum spacing ensures proficient exploitation of solar radiation and nutrients (mohaddesi et al., 2011). in contrast, beyond the optimum level, severe competitions (for light, nutrients, and water) slow down plant growth and decrease grain yield (bozorgi et al., 2011). considering these facts, the study was carried out with the objectives to find out the variety specific spacing for maximizing yield and yield contributing characters of transplanted aman rice. materials and methods experimental site and climatic conditions the experiment was conducted at a farmer's field at darbost union of jaintapurupazila, sylhet. the geographical location of the experimental plot lies between 24°59' and 25°11' north latitudes and in between 92°03' and 92°14' east longitudes at an elevation of 30m above the sea level. the experimental area was situated under sub-tropical climate, characterized by the heavy rainfall during kharif season (april to september), and lower in rabi season (october to march). the soil of the experimental site was sandy loam having medium fertility, belongs to the "khadimnagar" series under eastern surmakushiyara floodplain (frg,2012). the soil contains 1.45% organic matter, 0.8% n, 0.07 m mol k, 25 μg p and 10 μg s per 100 gof soil with a ph value of 5.0. experimental treatments and design the experiment included two factors, factor a-two varieties viz. brri dhan34 (v1) and binadhan-17 (v2), and factor bfour spacing viz. 15×10 cm (s1), 20×10 cm (s2), 20×15 cm (s3), 25×15 cm (s4); laid out in a factorial randomized complete block design (rcbd factorial) with three replications. input use and intercultural operations a piece of land was selected as nursery bed for raising seedlings. the experimental field was ploughed with a power tiller. weeds, stubbles and residues were removed and cleaned from the field. ploughing and cross ploughing was done thrice followed by laddering to prepare the land. the recommended fertilizers dose was n80p30k40s10zn25 ha−1 according to srdi, sylhet. one third of the urea and the whole amount of triple super phosphate (tsp), muriate of potash (mop), gypsum and zinc sulfate were applied as basal dose at the time of final land preparation and thoroughly incorporated into the soil. after uprooting the seedlings were similar sized 23 days old seedlings transplanted at the rate of three seedlings hill−1 maintaining spacing as per treatments. the rest of the urea fertilizer was applied in two equal splits; one at the maximum vegetative growth stage at 30 days after transplanting (dat), and another at 45 dat before panicle initiation stage. weeding was done at 30 dat in order to keep the crop weed free. irrigation water was applied during the cropping season as when necessary. plant protection measures were done as per requirements. sampling, harvesting and processing hills from the middle portion (1×1 m) of each unit plot excluding border rows were randomly selected soon after transplanting and marked with bamboo sticks for determining growth parameters as well as yield and yield components. the crop was harvested at full maturity confirming 80% golden yellow colored grains. after harvested the sampled area the crop of each plot was separately bundled, properly tagged and then brought to the threshing floor. after drying, the grains 14% moisture level was confirmed in the grains. the straws are also sun dried. performance of two aman rice varieties using varying plant density 3 data measurements the data on the plant height, flag leaf length, panicle length, the number of panicles, productive tillers and ineffective tillers were collected before harvesting. the data on filled, empty grain was counted from randomly selected 20 panicles from different random hills. thousands grain weight, grain yield, and straw yield were measured by an electric balance after the drying process. harvest index is basically the ratio of grain yield to total above ground biomass. finally harvest index was calculated according to the following equation (karki et al., 2018). harvest index (%) = grain yield above ground biomass × 100 statistical analysis the recorded data were compiled and analyzed statistically using statix10 computer package program and the analysis of variance were separated for significant difference by lsd test at 5% level of probability. results and discussion effect of spacing on growth parameters of rice varieties significant variations were observed between two varieties, brri dhan34 attains maximum plant height (126.08 cm) whereas binadhan-17 was shorter (81.83 cm). (table 1). similarly, plant spacing influences the plant height significantly. among the four spacing; tallest plant (111.50 cm) was recorded at 15×10 cm spacing, while, the shortest plant (94.50 cm) from 25×15 cm spacing (table 1). the combined effect of variety and spacing showed a significant variation where highest plant height (135.00 cm) was obtained from brri dhan34 planted at 15×10 cm spacing.. contrary the lower plant height (75.67 cm) was obtained when binadhan-17 planted at widest spacing (25×15 cm), which was statistically similar with binadhan-17 (80.33cm) planted at 20×15cm spacing the flag leafof binadhan-17 produced the longest flag leaf (32.58cm) in comparison to brri dhan34 (22.58 cm) (table 1). on the other hand, maximum flag leaf (29.00cm) was observed at 20×15cm spacing, which was statistically similar with 20×10 cm (28.83cm) and 15×10 cm (26.83cm) spacing while, the shortest flag leaf (25.67cm) at wider spacing (25×15cm) (table 1). maximum flag leaf length (34.33cm) was recorded from binadhan-17 planted at 20×10 cm spacing. on the other hand shortest flag leaf (19.67cm) was found from brri dhan34 planted in a spacing of 25×15cm. furthermore, grain yield is positively correlated to the length, width, and area of flag leaf (rahman et al., 2013). in our study, brri dhan34 produced the maximum flag leaf length at wider spacing (20×15 cm) but binadhan-17 produced maximum flag leaf length at closer spacing (20×10 cm), which might be attributed to the genetic makeup of the varieties. table 1. individual effect of varieties and spacing on plant height, flag leaf length, panicle length and number of panicle m−2 of rice treatments plant height (cm) flag leaf length (cm) panicle length (cm) panicle (no. m−2) variety 4 ahmed et al. brri dhan34 126.08±3.69 a 22.58 ±0.80 b 24.17 ±0.29a 265.73 ±3.02 a binadhan-17 81.83 ±2.75 b 32.59 ±0.52 a 19.92 ± 0.38b 265.95 ±3.53 a lsd(0.05) 1.84 1.33 1.48 5.73 spacing 15×10 cm 111.50 ±3.97 a 26.833±0.58 ab 23.00 ±1.73 a 334.00 ±4.58 a 20×10 cm 106.50 ±3.78 b 28.833 ±0.29 a 22.00 ±1.00 a 311.67 ±3.82 b 20×15 cm 103.33 ±1.90 b 29.000 ±1.32 a 21.83 ± 0.76 a 232.50 ± 1.5 c 25×15 cm 94.50 ±2.65 c 25.667 ±1.44 b 21.33 ± 0.76 a 185.20 ±1.83 d lsd(0.05) 3.52 2.55 2.83 10.98 means with dissimilar letters are significantly different at p ≤ 0.05 at lsd test. both maximum number of paniclesm−2 (265.95) and length of panicles were also high (24.17 cm) in binadhan-17 compared to brri dhan34 (265.73) and (19.92cm), respectively (table 1). notably, panicle length was not affected due to varied spacing, whereas, maximum number of panicle (334.00) was recorded at 15×10 cm spacing, where the lowest (185.20)at the wider spacing (25×15 cm) (table 1). moreover, brri dhan34 produced the longest panicle (25.33cm) when grown under 15×10 cm spacing, while binadhan-17 at 20×15cm and 25×15cm spacing produced the shortest panicle (19.33cm).combined effect of variety and spacing also showed that binadhan-17 produced the highest number of panicles m−2 (336.00) when planted by 15×10 cm, which was similar to brri dhan34 (332.00) planted by 15×10 cm spacing. on the other hand brri dhan34 planted 25×15 cm spacing produced the lowest number of panicles m−2 (181.60) planted 25×15 cm spacing, which was statistically similarto binadhan-17 (188.80) planted 25×15 cm spacing. on the other hand brri dhan34 produced longer panicle compared to binadhan-17, which might be due to genetic makeup of the variety. therefore, the result of our study corroborates with the findings of previous reports (sarker, 2012; ali et al., 2014; hossain et al., 2014; shiyam et al., 2014). effect of spacing on yield attributes of rice varieties both the varieties were indifferent regarding number of productive and infertile tillers hill−1. binadhan17 produced higher number of productive tillers hill−1 (6.84) but lower number of infertile tillers hill−1 (3.34). on the other hand brri dhan34 produced lower number of productive tillers hill−1 (6.79) but higher number of infertile tillers hill−1 (3.52) (table 2). the maximum number of productive tillers hill−1 (7.75) was found at 20×15 cm spacing followed by 25×15 cm spacing (7.72) and the lowest number of productive tillers hill−1 (5.57) at 15×10 cm spacing. the result also shows that maximum number of sterile tillers hill−1 (4.30) was found at 15×10 cm spacing followed by 20×10 cm (3.97) spacing and the lowest number of sterile tillers hill−1 (2.58) at 25×15 cm spacing (table2). in case of interaction effects, binadhan-17 recorded maximum number of productive tillers (7.87) planted 25×15 cm but was statistically at par with (7.80) planted 20×15cm, and brri dhan34 (7.70) planted 20×15cm. contrary the lowest number of effective tillers (5.53 was found at brri dhan34 planted 15×10 cm. again, maximum number of infertile tillers (4.50) was recorded at brri dhan34 with performance of two aman rice varieties using varying plant density 5 15×10 cm, which is statistically at par with binadhan-17 (4.20) with 20×10 cm and 15×10 cm (4.10). on the other side binadhan-17 produced the lowest number of sterile tillers (2.33) with 20×15 cm. fig.1. combined effect of varieties and spacing on plant height, flag leaf length, panicle length and number of panicle m−2 of rice. means with dissimilar letters are significantly different at p ≤ 0.05 by lsd test. table 2. individual effect of varieties and spacing on number of productive tillers hill−1, number of sterile tillers hill−1, number of filled and empty grains panicle−1 of rice treatments effective tillers (no. hill−1) infertile tillers (no. hill−1) filled grains (no. panicle−1) empty grains (no. hill−1) variety brri dhan34 6.79 ±0.07a 3.53 ± 0.07a 71.42 ± 1.23b 50.67 ±1.01a binadhan-17 6.84 ± 0.06a 3.34 ±0.09a 84.41 ± 0.52a 40.58 ±1.18b lsd (0.05) 0.13 0.21 2.51 2.75 spacing 15×10 cm 5.57 ±0.08 c 4.30 ±0.09 a 54.50 ±2.78c 67.83 ±1.04a 20×10 cm 6.23 ±0.08b 3.97 ±1.76a 76.00 ±0.5b 50.17 ±1.04b 20×15 cm 7.75 ±0.05a 2.88 ±1.19b 90.33 ±2.57a 36.00 ± 2.29c 25×15 cm 7.72 ± 0.08a 2.58 ±0.10b 90.83 ±2.84a 28.50 ±2.78d lsd (0.05) 0.25 0.40 4.80 5.28 means with dissimilar letters are significantly different at p ≤ 0.05 by lsd test. a ab b c d de ef f 0 30 60 90 120 150 180 p la n t h ei g h t (c m ) brri dhan34 binadhan-17 a bc bc b c a a a a 0 10 20 30 40 50 f la g l ea f le n g th ( cm ) brri dhan34 binadhan-17 b a a-c ab a-ca-c bc c c 0 10 20 30 40 15 10 cm 20 10 cm 20 15 cm 25 15 cm p an ic le l en g th ( cm ) spacing c a ab c d a b c d 0 100 200 300 400 500 15 10 cm 20 10 cm 20 15 cm 25 15 cm p an ic le ( n o . m − 2 ) spacing d 6 ahmed et al. binadhan-17 produced higher number of filled grain panicle−1 (84.42) but lower number empty grain panicle−1 (40.58). on the other hand lower number of filled grain panicle−1 (71.41) and higher number of empty grain panicle−1 (50.67) was recorded from brri dhan34 (table 2). maximum number of filled grain panicle−1 (90.83) was noticed at 25×15 cm spacing, which was statistically similar with 20×15 cm spacing (90.33), but the lowest number of filled grain panicle−1 (54.50) at 15×10 cm spacing. moreover, maximum number of empty grain hill−1 (67.83) was recorded at 15×10 cm spacing, while the lowest number of empty grain hill−1 (28.50) was recorded at 25×15 cm spacing (table 2).. the highest number filled grain (95.67) was obtained at binadhan-17 with 20×15 cm and 25×15 cm but the lowest number of filled grain (54.00) with 15×10 cm. the interaction effect showed significant variation for empty grain. the highest no of empty grain (69.67) was recorded at binadhan-17 with 15×10 cm, which is statistically similar with brri dhan34 (66.00) at 15×10 cm and (65.00) at 20×10 cm. on the other hand the lowest number of empty grain (23.00) was recorded at binadhan-17 than with 25×15 cm. in case of binadhan-17 did not found any variation regarding number of filled grains among 20×10 cm, 20×15 cm and 25×15 cm of spacing, which might be due to the intrinsic capacity of this variety under the competitive condition for natural resources (water, nutrients, air and light). on the other hand number of empty grains increased drastically under closer spacing in brri dhan34. sarker et al. (2002) found that under increased number of plants per unit area under closer spacing reduced the number of grains per panicle as well as increased the number of empty grains, which supports the results (figure2). c b a a c b a a 0 2 4 6 8 10 12 p ro d u ct iv e ti ll er s (n o . h il l− 1 ) brri dhan34 binadhan-17 a a b cd c ab ab d cd 0 1 2 3 4 5 6 7 s te ri le t il le rs ( n o . h il l− 1 ) brri dhan34 binadhan-17 b c c b b c ab a a 0 20 40 60 80 100 120 140 15 10 cm 20 10 cm 20 15 cm 25 15 cm f il le d g ra in s (n o . p an ic le − 1 ) spacing c a a b b a b b c 0 10 20 30 40 50 60 70 80 90 100 15 10 cm 20 10 cm 20 15 cm 25 15 cm e m p ty g ra in s (n o . h il l− 1 ) spacing d performance of two aman rice varieties using varying plant density 7 fig. 2. combined effect of varieties and spacing on number of productive tillers hill−1, number of sterile tillers hill−1, number of filled and empty grains panicle−1 of rice. means with dissimilar letters are significantly different at p ≤ 0.05 by lsd test. effect of spacing on grain weight, yield and harvest index of rice. grain weight is one of the important factors for increasing rice grain yield (huang et al., 2013). thousands grain weight of any variety is dependent on both grain size and grain filling rate. although grain size is regulated by genetic factors, grain filling rate is governed by the macro and micro climate of the field (xie et al., 2015). binadhan-17 had statistically heavier thousands grain weight (23.83) than brri dhan34 (17.32) (table3).. the heavier thousands grain weight (21.28g) was noticed at 25×15 cm which is statistically similar with 20×15 cm (21.23g) while lower thousands grain weight (19.42g) at 15×10 cm (table 3). binadhan-17 produces the same thousands grain weight (24.80g) at 20×15 cm and 25×15 cm. on the other hand, brri dhan34 produces the lower thousands grain weight (16.63g) at 15×10 cm. rice grain yield depended on the length and number of panicles, number of fertile and sterile tillers, number of filled and empty grains per panicle as well as thousand grain weights (melkie and takele, 2020). varieties had significant effect on grain yield. binadhan-17 produced statistically higher grain yield (5.17 t ha−1) than brri dhan34 (3.14 t ha−1) (table 3). it was found that spacing had significant effect on grain yield. the highest grain yield (4.93 t ha−1) was found at 20×10 cm followed by 20×15 cm (4.51 t ha−1) and the lowest grain yield (3.54 t ha−1) at 15×10 cm. (table3). the interaction effect showed significant variation grain yield.binadhan-17 produced maximum grain yield (6.55 t ha−1) with 20×10 cm followed by 20×15 cm (5.55 t ha−1) and the lowest grain yield (4.10 t ha−1) at 15×10 cm. on the other side, brri dhan34 produced maximum grain yield (3.47 t ha−1) with 20×15 cm followed by 20×10 cm (3.32 t ha−1) and the lowest grain yield (2.77 t ha−1) with 25×15 cm.grain yield was significantly influenced by varieties and spacing. binadhan-17 produced maximum grain yield at closer spacing (20×10 cm) but brri dhan34 produced maximum grain yield at wider spacing (20×15cm). in wider spacing (20×15cm) flag leaf length is maximum, maximum number of effective tiller hill−1, least number of sterile tillers hill−1, maximum number of filled grains m−2 contributed to increase grain weight m−2, which ultimately increased grain yield of brri dhan34. similar findings were also obtained by other researchers, who reported that an increased number of effective tillers hill−1, as well as higher number of grains panicle−1 increased grain yield ha−1 (uddin et al., 2011, shiyam et al., 2014). on the other hand binadhan-17 achieved significantly maximum flag leaf length, maximum number of filled grains m−2, maximum grain weight m−2, helped to increase grain yield in closer spacing (20×10 cm). similar finding had also been reported by bhowmick and nayak (2000) and boling et al. (2004)(figure 3). table 3. individual effect of varieties and spacing on thousands grain weight, grain and straw yield ha−1, and harvest index of rice treatments thousands grain weight (g) grain yield (t ha−1) straw y (t ha−1) harvest index (%) variety brri dhan34 17.32 ±0.52b 3.1357 ±0.08b 4.7350± 0.13b 39.818 ±0.14b binadhan-17 23.83 ±0.04a 5.1691 ±0.04 a 7.0731±0.06a 42.097 ±0.02a lsd (0.05) 0.12 0.11 0.19 0.30 spacing 8 ahmed et al. 15×10 cm 19.42 ±0.03c 3.5408 ±0.11c 5.3882 ±0.22c 39.480 ±0.23d 20×10 cm 20.35±0.09b 4.9334 ±0.04a 6.8551± 0.08a 41.296±0.22b 20×15 cm 21.23 ±0.03a 4.5089 ±0.11b 6.1342 ±0.18b 42.415 ±0.32a 25×15 cm 21.28 ±0.03a 3.6266 ±0.09c 5.2387 ±0.13c 40.639 ±0.04c lsd (0.05) 0.24 0.21 0.36 0.57 means with dissimilar letters are significantly different at p ≤ 0.05 by lsd test. the variety binadhan-17 produced highest straw yield (7.07 t ha−1) whereas brri dhan34 produced straw yield of 4.74 t ha−1 (table 3).spacing was also significantly influenced by straw yield. the highest straw yield (6.86 t ha−1) was found at 20×10 cm followed by 20×15 cm (6.13 t ha−1) and the lowest straw yield (5.24 t ha−1) at 25×15 cm. (table 3). the interaction effect showed significant variation on straw yield. the maximum straw yield (8.58 t ha−1) was recorded at binadhan-17 with 20×10 cm followed by 20×15 cm (7.60 t ha−1) and the lowest straw yield (5.91 t ha−1) with 15×10 cm. on the other hand, brri dhan34 produced maximum straw yield (5.13 t ha−1) with 20×10 cm followed by 15×10 cm (4.87 t ha−1) and 20×15 cm (4.67 t ha−1) but the lowest straw yield (4.28 t ha−1) with 25×15 cm. on the other hand binadhan-17 produced higher amount of straw compared to brri dhan34 (figure 3), which might be due to the genetic makeup of the variety that favored the production of maximum straw. f e d d c b a a 0 5 10 15 20 25 30 35 40 1 0 0 0 g ra in w ei g h t (g ) brri dhan34 binadhan-17 a fg ef e g d a b c 0 2 4 6 8 10 g ra in y ie ld ( t h a− 1 ) brri dhan34 binadhan-17 b de d de e c a b c 0 2 4 6 8 10 12 14 15 10 cm 20 10 cm 20 15 cm 25 15 cm s tr aw y ie ld ( t h a− 1 ) spacing c e d ab dc a b b 0 10 20 30 40 50 60 15 10 cm 20 10 cm 20 15 cm 25 15 cm h ar v es t in d ex ( % ) spacing d performance of two aman rice varieties using varying plant density 9 fig. 3. combined effect of varieties and spacing on thousands grain weight, grain and straw yield ha−1, and harvest index of rice. means with dissimilar letters are significantly different at p ≤ 0.05 by lsd test. the varieties with higher harvest index produced higher grain yield due to higher dry matter accumulation and partitioning into the panicles (hay, 1995). varieties showed significant influence on harvest index. binadhan-17 gave higher harvest index (42.09) than brri dhan34 (39.82) (table3). maximum harvest index (42.42) was found at 20×15 cm followed by 20×10 cm (41.29) but the lowest harvest index (39.48) at 15×10 cm. (table 3). harvest index significantly affected by varieties and spacing. binadhan-17 had the maximum harvest index (43.27) with 20×10 cm, which is statistically similar to brri dhan34 (42.62) with 20×15 cm. on the other side the lowest harvest index (38.01) was recorded at brri dhan34 with 15×10 cm. moreover, the yield and harvest index differed due to genetic differences among varieties. grain yield increases because of higher dry matter production due to maximum number of effective tillers, longest flag leaf length, maximum number of filled grain, as well as heavier grain weight. in general harvest index was higher in those rice varieties efficient in translocation of assimilates to the sink (grain) for higher economic yield (alam et al., 2009)(figure3). conclusion from the study, it is revealed that both variety and plant density are important factors for better yield of aman rice in northeastern region of bangladesh. the results showed that binadahn-17 produced higher yield compared to brri dhan34. among the plant density treatments 20×10 cm and 20×15 cm spacing showed better results in terms of yield contributing characters. the interaction effect showed that binadahn-17 produced higher yield when grown under 20×10 cm spacing, while brri dhan34 produced maximum yield with 20×15 cm spacing. therefore, it can be suggested t t.aman var. binadhan-17 could be transplanted at 20×10 cm spacing for getting maximum yield in northeastern region of bangladesh. acknowledgement the authors would like to acknowledge the ministry of science and technology for financial support to conduct the research and department of agronomy and haor agriculture for providing facilities. references agostinetto, d., m.a. nohatto, c.p. tarouco, j.j. franco and e.d.f.f. da rosa. 2018. physiology of rice and red rice plants in competition for nitrogen. científica 46(3):293–298. akter, n., e.kayesh, m.m. hossain and m.s.alam. 2019. morphological and physicochemical characterization of burmese grape (baccaurea ramiflora lour.). fundam. appl. agric. 4(2): 829– 838. alam, m.m., m.h. ali, a.k.m.r. amin and m. hasanuzzaman. 2009. yield attributes, yield and harvest index of three irrigated rice varieties under different levels of phosphorus. adv. biol. re. 3:132– 139. ali, m.a., m.a. sattar, m.n. islam and k. inubushi. 2014. integrated effects of organic, inorganic and biological amendments on methane emission, soil quality and rice productivity in irrigated paddy 10 ahmed et al. ecosystem of bangladesh: field study of two consecutive rice growing seasons. plant soil. 378: 239–252. anik, s.i. and m.a.s.a. khan. 2012. climate change adaptation through local knowledge in the north eastern region of bangladesh. mitig. adapt. strateg. glob. change. 17: 879–896. ashrafuzzaman, m., m.r. islam, s.m. shahidullah and m.m. hanafi. 2009. evaluation of six aromatic rice cultivars for yield and yield contributing characters. int. j. agric. biol. 11:616–620. awan, t.h., r.i. ali, z. manzoor, m. ahmad and m. akhtar. 2011. effect of different nitrogen levels and row spacing on the performance of newly evolved medium grain rice variety, ksk-133. j. anim. plant sci. 21: 231–234. bajpai, a. and y. singh. 2010. study of quality characteristics of small and medium grained aromatic rice of uttar pradesh and uttarakhand. agric. sci. dig. 30: 241–245. bbs. 2019. the yearbook of agricultural statistics of bangladesh. bangladesh bureau of statistics, statistics division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh, p.54. bezbaruha, r., r.c. sharma, and p. banik. 2011. effect of nutrient management and planting geometry on productivity of hybrid rice (oryza sativa l.) cultivars. am. j. plant sci. 2: 297–302. bhowmick, n. and r.l. nayak. 2000. response of hybrid rice (oryza sativa) varieties to nitrogen, phosphorus and potassium fertilizers during dry (boro) season in west bengal. indian j. agron. 45: 323–326. bhowmik, s.k., m.a.r. sarkar and f. zaman. 2012. effect of spacing and number of seedlings per hill on the performance of aus rice cv. nerica 1 under dry direct seeded rice (ddsr) system of cultivation. j. bangladesh agric. univ. 10:191–195. biswas, b. 2008. crop-weather-disease interaction in rice crop. m.sc. thesis. punjab agricultural university, ludhiana, punjab, india. boling, a., t.p. tuong, s.y. jatmiko and m.a. burac. 2004. yield constraints of rainfed lowland rice in central java, indonesia. field crop res. 90: 351–360. bozorgi, h.r., a. faraji and r.k. danesh. 2011. effect of plant density on yield and yield components of rice. world appl. sci. j. 12:2053–2057. donald, c.m. and j. hamblin. 1976. the biological yield and harvest index of cereals as agronomic and plant breeding criteria. adv. agron. 28:361–405. fernandez, c.j., d.d. fromme and w.j. grichar. 2012. grain sorghum response to row spacing and plant populations in the texas coastal bend region. int. j. agron. 238634. doi:10.1155/2012/238634. frg. 2012. fertilizer recommendation guide. bangladesh agricultural research council (barc), dhaka, bangladesh. p.27. garcia, g.a., m.f. dreccer, d.j. miralles and r.a. serrago. 2015. high night temperatures during grain number determination reduce wheat and barleygrain yield: a field study. glob. chang. biol. 21: 4153–4164. gunri, s.k., s.k. pal and a. chaudhury. 2004. effect of integrated nitrogen application on yield of rice in foot hill soil of west bengal. indian j. agron.49:248–250. hay, r.k.m. 1995. harvest index: a review of its use in plant breeding and crop physiology. ann. appl. biol. 126(1):197–216. hirooka, y., k. homma, t. shiraiwa, y. makino, t.s. liu, z. xu and l. tang. 2018. yield and growth characteristics of erect panicle type rice (oryza sativa l.) cultivar, shennong265 under various crop management practices in western japan. plant prod. sci. 21: 1–7. hossain, m.m., f. sultana and a.h.m.a. rahman. 2014. a comparative screening of hybrid, modern cultivars and local rice cultivar for brown leaf spot disease susceptibility and yield performance. arch. phytopath. plant prot.47: 795–802. huang, r., l. jiang, j. zheng, t. wang, h. wang, y. huang and z. hong. 2013. genetic bases of rice grain shape: so many genes, so little known. trends plant sci. 18: 218–226. performance of two aman rice varieties using varying plant density 11 imade, s.r., j.d. thanki and n.n. gudadhe. 2015. integrated effect of organic manures and inorganic fertilizers on productivity, npk uptake and profitability of transplanted rice. res. crops. 16: 401– 405. irri. 1997. rice production manual, international rice research institute, uplb, los banos, philippines. p.95. ishfaq, m., n. akbar, i. khan, s.a. anjum, u. zulfiqar, m. ahmad, m. ahmad and m.u. chattha.2018. optimizing row spacing for direct seeded aerobic rice under dry and moist fields. pak. j. agric. res. 31(4): 291–299. kandil, a.a., s.e. el-kalla, a.t. badawi and o.m. el-shayb. 2010. effect of hill spacing, nitrogen levels and harvest date on rice productivity and grain quality. crop environ. 1: 22–26. karki, s., n.s. poudel, g. bhusal, s. simkhada, b.r. regmi, b. adhikari and s. poudel. 2018. growth parameter and yield attributes of rice (oryza sativa) as influenced by different combination of nitrogen sources.world j. agric. res. 6:58–64. karmakar, b., m.a. ali, m.a. mazid, j. duxbury and c.a. meizner. 2004. validation of system of rice intensification (sri) practice through spacing, seedling age and water management. bangladesh agron. j. 10:13–21. khaliq, a., m.y. riaz and a. matloob. 2011. bio-economic assessment of chemical and non-chemical weed management strategies in dry seeded fine rice (oryza sativa l.). int. j.plant breed. crop sci. 3:302–310. khan, m.a.h., m.m. alam, m.i. hossain, m.h. rashid, m.i.u. mollah, m.a. quddus, m.i.b. miah, m.a.a. sikder and j.k. ladha. 2009. validation and delivery of improved technologies in the rice-wheat ecosystem in bangladesh. in: j.k. ladha, y. sing, o. erenstein, b. hardy (eds.)integrated crop and resource management in the rice-wheat system of south asia. international rice research institute, los banos, philipine. pp.197–220. khush, g.s. 1993. breeding rice for sustainable agriculture systems. in: d.r. buxton, r. shibles, r.a. forsberg, b.l. blad, k.h. asay, g.m. paulsen, r.f. wilson (eds.) international crop science i. the crop science society of america, inc. madison, wisconsin, usa. pp.189–199. lesk, c., p. rowhani and n. ramankutty. 2016. influence of extreme weather disasters on global crop production. nature 529: 84–87. matusmoto, t., k.yamada, y. yoshizawa and k.m. oh.2016. comparison of effect of brassinosteroid and gibberellin biosynthesis inhibitors on growth of rice seedlings. rice sci. 23:51–55. melkie, z. and k.b.a. takele. 2020. effect of nitrogen fertilizer levels and row spacing on yield and yield components of upland rice varieties in pawe, northwestern ethiopia.j. nat. sci. res. 10:1– 12. mohaddesi, a., a. abbasian, s. bakhshipour and h. aminpanah. 2011. effect of different levels of nitrogen and plant spacing on yield, yield components and physiological indices in high-yield rice (number 843).american-eurasian j. agric. enviro. sci. 10: 893–900. montgomery, d.c. 2013. design and analysis of experiments (eighth edition). john wiley & sons, inc. hovoken, nj, usa. prasad, p.v.v., k.j. boote, l.h. allen jr, j.e. sheehy and j.m.g. thomas. 2006. species, ecotype and cultivar differences in spikelet fertility and harvest index of rice in response to high temperature stress. field crop res. 95: 398–411. rahman, m.a., m.e. haque, b. sikdar, m.a. islam and m.n. matin. 2013. correlation analysis of flag leaf with yield in several rice cultivars. j. life earth sci. 8: 49–54. rahman, m.s., m.p. anwar, m.m. rahman, m.a. islam and m.m. rahman. 2007. effect of spacing and weeding regime on the growth and yield of aus rice.cv. br26. bangladesh j. progressive sci. technol. 5(1):129–132. sarker, a.k. 2012. effect of cultivars and nitrogen level on yield and yield performance of transplanted amanrice. m.s thesis in agronomy, bangladesh agricultural university, mymensingh. p.25. 12 ahmed et al. sarker, g., m. rahman, r. hasan and s.c. roy. 2002. system of rice intensification: yield and economic potential in boro rice at different locations of bangladesh. life-nopest project, carebangladesh. pp.1–5. sayeed, k.a. and yunus, m.m. 2018. rice prices and growth, and poverty reduction in bangladesh. food and agriculture organization of the united nations. background paper to the unctad-fao commodities and development report 2017, commodity markets, economic growth and development, food and agriculture organization of the united nations, rome, italy. pp.11–13. sharada, p. and p. sujathamma. 2018. effect of organic and inorganic fertilizers on the quantitative and qualitative parameters of rice (oriza sativa l.). current agri. res. 6: 12–19. shiyam, j.o., w.b. binang and m.a. ittah. 2014. evaluation of growth and yield attributes of some lowland chinese hybrid rice (oryza sativa l.) cultivars in the coastal humid forest zone of nigeria. iosr j. agric. vet. sci. 7(2): 70–73. singh, y and u.s. singh. 2008. genetic diversity analysis in aromatic rice germplasm using agro morphological traits. j. plant genet. resour. 21(1): 32–37. srinagar, k. 2012. evaluation of plant spacing and seedlings per hill on rice (oryza sativa l.) productivity under temperate conditions. pak. j. agri. sci. 49(2): 169-172. surek, h and n. beser. 2003. correlation and path coefficient analysis for some yield-related traits in rice (oryza sativa l.) under thrace conditions. turkey j. agric. for. 27:77–83. thakur, a.k., s.k. chaudhari, r. singh and a. kumar. 2009. performance of rice cultivars at different spacing grown by the system of rice intensification in eastern india. indian j. agric. sci. 79: 443– 447. tian, y., h. zhang, p. xu, x. chen, y. liao and b. han. 2015. genetic mapping of a qtl controlling leaf width and grain number in rice. euphytica 202:1–11. uddin, m.j., s. ahmed, h.m. rashid, m.a. hasan and m. asaduzzaman. 2011. effect of spacing on the yield and yield attributes of transplanted aman rice cultivars in medium lowland ecosystem of bangladesh j. agric. res. 49(4): 465–476. usda. 2020. world agricultural production, circular series wap 06-20. foreign agricultural service, united states department of agriculture, washington dc, usa. p.39. wang, d., j. huang, l. nie, f. wang, x. ling, k. cui, y. li and s. peng. 2017. integrated crop management practices for maximizing grain yield of double-season rice crop. sci. rep. 7:38982. doi:10.1038/srep38982. xie, q., s. mayes and d.l. sparkes. 2015. carpel size, grain filling, and morphology determine individual grain weight in wheat. j. exp. bot. 66:6715–6730. xue, w., y. xing, x. weng, y. zhao, w. tang, l. wang, h. zhou, s.yu, c. xu, x. li and q. zhang. 2008. natural variation in ghd7 is an important regulator of heading date and yield potential in rice. nat. genet. 40: 761–767. yu, h., z. qiu, q. xu, z. wang, d. zeng, j. hu, g. zhang, l. zhu, z. gao, g. chen and l. guo. 2017. fine mapping of lowtiller 1, a gene controlling tillering and panicle branching in rice. plant growth regul. 83: 93–104. bangladesh agron. j. 2022, 25(2): 83-87 intercropping of pea and kheshari as vegetables and fodder crop with dwarf type sunflower variety p. roy1 and f.begum2 1&2 scientific officer and chief scientific officer, oilseed research centre, bangladesh agricultural research institute, joydebpur, gazipur (received: 21 november 2022, accepted: 30 december 2022) keywords: intercrop, sunflower, yield, bcr abstract to find out the optimum row arrangement of pea and khesari as intercrop with sunflower for higher productivity and return, a field experiment of intercropping pea and khesari with sunflower was conducted in oilseed research centre, bari, gazipur during rabi season of 2020-21 and 2021-22. six treatments were t1= sole sunflower, t2 = one row of gardenpea in between two normal rows of sunflower (50 cm x 25 cm), t3 = two rows of gardenpea in between two normal rows of sunflower, t4 = one row of kheshari in between two normal rows of sunflower (50cm x 25cm), t5 = two rows of kheshari in between two normal rows of sunflower & t6= broadcast kheshari in between two normal rows of sunflower. although intercropping reduced sunflower yield but total productivity was increased due to addition of pea and khesari yield. total productivity in terms of sunflower equivalent yield (sey) (7.02 t ha-1 and 6.64 t ha-1 during 2020-21 and 2021-22 respectively) was found to be highest from t3 (two rows of pea in between two normal rows of sunflower treatment while the lowest (1.80 t ha-1 and 1.72 t ha-1) in t1 (sole sunflower) for both the years. highest benefit cost ratio (bcr) (4.0 and 3.80 in 1st and 2nd year respectively) was recorded in t2 treatment (one row of gardenpea in between two normal rows of sunflower) with highest gross margin (tk. 263905 ha-1 and tk. 244012 ha-1). introduction intensive sunflower production is mainly focused on increasing seed yield, but less importance is given to soil properties, potential ecosystem services and resource conservation. this practice can cause the reduction in organic matter content in the soil, loss of soil fertility, increased erosion, as well as pollution of ground waters. hence, it is necessary to introduce alternative practices such as intercropping that has raised much attention because it could improve agriculture production for many crops. previous research has show that it is best to combine two crops, including one from the fabaceae family. plants from this family have the ability to create a large amount of above-ground mass, strong root systems with high absorption power, ability to adapt to shady conditions, suppressive effect on weeds and the ability to fix atmospheric nitrogen and provide nitrogen for other plant species that are intercropped with (de la fuente et al., 2014). commonly intercropped with legumes are crops from а poaceae family, whereas the combination of sunflower with legumes is relatively rare. the reason for this may be that in an earlier period there were no hybrids tolerant to different diseases and pests. however, today there are justifiable reasons for studying combinations of sunflower and the most important legumes. the goal of this research is to analyze and recommend sustainable technology of 84 roy et al. sunflower cultivation in intercropping systems and select the legumes most suitable for intercropping with sunflower, aiming to increase productivity per unit area. materials and methods the field experiment was conducted at the research field of oilseed research centre, bangladesh agricultural research institute, gazipur during rabi season of 2020-21 and 20212022. there were six treatments viz. t1 = sole sunflower, t2 = one row of gardenpea in between two normal rows of sunflower (50 cm x 25 cm), t3 = two rows of gardenpea in between two normal rows of sunflower, t4 = one row of kheshari in between two normal rows of sunflower (50 cm x 25 cm), t5 = two rows of kheshari in between two normal rows of sunflower & t6=broadcast kheshari in between two normal rows of sunflower. the experiment was laid out in randomized complete block design with three replications. the unit plot size was 4m x 5m. both the seeds of sunflower (bari surjomukhi-3), khesari (bari khesari-4) and gardenpea (bari motorshuti-3) were sown on 18 november and 21 november during 2020 and 2021 respectively. fertilizers at the rate of n88p34k80s28zn3b2 kg ha-1 in the form of urea, tsp, mop, gypsum, zinc oxide and boric acid, respectively. full amount of triple super phosphate, muriate of potash, gypsum, zinc oxide, boric acid and half of urea were broadcasted in the experimental plot at the time of final land preparation. the rest half of urea was applied in equal amounts at 30 and 55 days after sowing (das). at harvest, the yield data was recorded plot wise. collected data were analyzed statistically and means were adjusted by lsd test at 5% level of significance using spss. yield of individual crops was converted to sunflower equivalent yield (sey) considering prevailing market price of the crops according to bandyopadhyay (1984). marginal benefit cost analysis was also done. sunflower equivalent yield (sey) (kg/ha) = yis + (yig*pg) / ps &yis + (yik*pg) / pk where, yis = sunflower yield (kg/ha) in intercropping yig = gardenpea yield (kg/ha) in intercropping yik = khesari yield (kg/ha) in intercropping pg = price of gardenpea pk = price of khesari ps = price of sunflower results and discussion light availability average data on light availability during the crop growth period of two consecutive years in this study is representing in figure 1. availability of light on sunflower and pea & khesari intercropping was not markedly affected with each other. because pea & khesari were harvested at 70 to 100 das. at that time sunflower canopy could not produce much shade which might affect gardenpea & khesari. irrespective of treatments availability of light on pea & khesari canopy was almost 100% at earlier growth stage, 30 das of gardenpea & khesari and it decreased with the increase of shade produced by sunflower canopy over the time up to 60 das or up to harvest of gardenpea & khesari. however, among the intercropping treatments, the higher light availability on intercrop system was observed int1 treatment followed by t2 throughout the growing period. the lower light availability on sunflower was observed in t5 treatment. intercropping pea and kheshari with dwarf type sunflower 85 fig 1. average light availability on sunflower and pea & khesari intercropping during rabi season 2020-21 and 2021-22 effect of sunflower seed yield and yield attributes of sunflower was significantly influenced by intercropping system where as total number of branches per plant and seeds per plant did not show any significant difference (table 1). two years average data (2020-21 and 2021-22) on different yield attributing characters are representing here in table 1. total number of seeds per plant, mature seeds per plant, immature seed per plant, 100 seeds weight and yield of sunflower were significantly differed under different treatment combinations. plant height showed higher in treatment t1 and others are similar. maximum number of seeds per plant (801), mature seed per plant (669) and highest seed yield (1.72 t ha-1) were obtained from sole crop (t1). lowest yield (1.33 t ha-1) was obtained from t6 treatment which might be due to lowest number of mature seed per plant (455) and lower 1000 seed weight (61.02 g). table 1. yield and yield components (in average) of sunflower under sunflower + pea and sunflower + khesari intercropping system during rabi season 2020-21 and 2021-22 treatments days to 1st flow. days to maturity plant height (cm) seeds head-1 (no.) mature seeds head-1 (no.) immature seeds head-1 (no.) head diameter (cm) 100 seed wt. (g) seed yield (t ha-1) 202021 202122 t1 32 95 79.02 801 669 132 20.01 78.28 1.88 1.72 t2 30 95 77.05 753 689 64 18.50 76.51 1.76 1.56 t3 31 95 76.13 720 625 95 18.11 62.30 1.62 1.42 t4 32 95 77.10 755 650 105 14.33 75.12 1.70 1.60 t5 31 95 75.22 622 605 117 12.20 61.13 1.63 1.45 t6 34 95 77.90 580 455 125 11.13 61.02 1.50 1.33 lsd (0.05) ns ns 4.9 5.5 2.2 1.8 ns 1.7 1.7 1.2 cv (%) 1.8 8.4 9.2 8.1 4.2 1.6 5.7 t1= sole sunflower, t2 = one row of gardenpea in between two normal rows of sunflower (50 cm x 25 cm), t3 = two rows of gardenpea in between two normal rows of sunflower, t4 = one row of kheshari in between two normal rows of sunflower (50 cm x 25 cm), t5 = two rows of kheshari in between two normal rows of sunflower and t6= broadcast kheshari in between two normal rows of sunflower. 86 roy et al. companion crop yield in intercropping system, the highest yield (4.50 t ha-1 and 4.35 t ha-1 during 2020-21 and 2021-22) of pea was recorded when it was intercropped as two rows of pea in between two normal rows of sunflower (t3). the lowest yield of pea was observed in t2 (4.30 t ha-1 and 4.20 t ha-1 during 2020-21 and 2021-22) (table 2 and 3). in case of khesari, yield was highest (4.83 t ha-1 and 4.62 t ha-1 during 2020-21 and 2021-22) in t5 i.e. two rows of kheshari in between two normal rows of sunflower and lowest (2.88 t ha-1 and 2.44 t ha-1 during 2020-21 and 2021-22) in t6 when it was broadcasted with sunflower which might be due to the lower plant population at harvest. intercrop efficiency table 2 and 3 show the cost return analysis of sunflower with pea and khesari intercropping system in the year 2020-21 and 2021-22 respectively. it was observed that all the intercrop combinations produced higher sunflower equivalent yield (sey) over the sole sunflower. table 2. sunflower equivalent yield and benefit cost analysis of sunflower + pea and sunflower + khesari intercropping system during rabi season 2020-21 treatments companion crop yield (t ha-1) sunflower equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 1.80 90000 62100 27900 1.44 t2 4.38 7.01 350500 86595 263905 4.00 t3 4.50 7.02 351000 87988 263012 3.98 t4 3.91 2.48 124000 64550 56450 1.83 t5 4.83 2.59 129500 68320 61180 1.89 t6 2.88 2.07 103500 67110 36390 1.54 t1= sole sunflower, t2 = one row of gardenpea in between two normal rows of sunflower (50 cm x 25 cm), t3 = two rows of gardenpea in between two normal rows of sunflower, t4 = one row of kheshari in between two normal rows of sunflower (50 cm x 25 cm), t5 = two rows of kheshari in between two normal rows of sunflower and t6=broadcast kheshari in between two normal rows of sunflower. selling price: sunflower seed = tk.50 kg-1, pea = tk.60 kg-1 (green vegetable), khesari= tk.10 kg-1 (green vegetable) table 3. sunflower equivalent yield and benefit cost analysis of sunflower + pea and sunflower + khesari intercropping system during rabi season 2021-22 treatments companion crop yield (t ha-1) sunflower equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) gross margin (tk. ha-1) bcr t1 1.72 86000 62100 23900 1.37 t2 4.20 6.60 330000 85595 244405 3.80 t3 4.35 6.64 332000 87988 244012 3.77 t4 3.50 2.30 115000 64550 50450 1.78 t5 4.62 2.37 118500 68320 50180 1.73 t6 2.44 1.81 90500 67110 23390 1.34 t1= sole sunflower, t2 = one row of gardenpea in between two normal rows of sunflower (50 cm x 25 cm), t3 = two rows of gardenpea in between two normal rows of sunflower, t4 = one row of kheshari in between two normal rows of sunflower (50 cm x 25 cm), t5 = two rows of kheshari in between two normal rows of sunflower andt6=broadcast kheshari in between two normal rows of sunflower. selling price: sunflower seed = tk. 50 kg-1, pea = tk. 60 kg-1 (green vegetable), khesari= tk.10 kg-1 (green vegetable) intercropping pea and kheshari with dwarf type sunflower 87 the highest sey (7.03 t ha-1 and 6.64 t ha-1) was obtained from t3 (two rows of pea in between two normal rows of sunflower) treatment while the lowest (1.80 t/ha and 1.72 t ha-1) in sole sunflower for both the years. in both the year trials, maximum gross return (tk. 351000 ha-1 and 332000 ha-1) was recorded in t3 (two rows of pea in between two normal rows of sunflower) with highest gross margin (tk. 263905 ha-1 and 244405 ha-1) was in t2 (one row of gardenpea in between two normal rows of sunflower) treatment. however, the highest benefit cost ratio (bcr) (4.00 and 3.80 during 2020-21 and 2021-22) was obtained from t2 (one row of pea in between two normal rows of sunflower) treatment which might be due to higher sey and gross return. all the intercrop treatments showed much higher benefit over sole sunflower but highest in one row of pea in between two normal rows of sunflower. conclusion results revealed that among the intercropping treatments, the higher light availability on intercrop system was observed in sole crop followed by the intercrop of one row of gardenpea in between two normal rows of sunflower throughout the growing period. the lower light availability on sunflower was observed two rows of kheshari in between two normal rows of sunflower were intercropped. seed yield was highest in sole crop than all the intercrop system. however by considering the gross margin, gross return and bcr, inercropping of one row of gardenpea in between two normal rows of sunflower would be agronomically feasible and economically profitable for the farmers in intercropping system. references bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping system. ph. d. dissertation, indian agricultural research institute, new delhi. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effects on the physiological attributes and productivity of maize + bushbean intercropping system. bangladesh j. agril. res. 31(3): 353-364. mahfuza, s.n., m.n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping different vegetables and spices with pointed ground. j. expt. biosci. 3(1): 77-82. reddy, m.s. and r.w. willey. 1981. growth and resource use studies in an intercrop of pearl milled/sunflower. field crops res. 4: 13-24. microsoft word 8. baj-475e bangladesh agron. j. 2024, 26(2): 56-66 effect of bispyribac-sodium and spacing on the weed control and performance of aromatic rice varieties f.t.z. bushra1, t.a. sourav2, s.c. sarker3 and s.m. masum3* 1ms student, department of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh 2undergraduate student, faculty of agriculture, sher-e-bangla agricultural university, dhaka, bangladesgh 3departement of agronomy, sher-e-bangla agricultural university, dhaka, bangladesh *corresponding author, email: smmasum607@yahoo.com (received: 11 march 2024, accepted: 29 april 2024) keywords: aromatic rice, plant geometry, herbicide, weed control efficiency, weed index abstract rice (oryza sativa l.), a staple grain, serves as a fundamental dietary component for billions by providing carbohydrates, vitamins, and minerals, supporting livelihoods, and stimulating national economies. a field experiment was led from july to december 2019 at the sher-e-bangla agricultural university’s agronomy field in dhaka, bangladesh, to determine how a post-emergent herbicide and spacing impacts aromatic rice varieties' growth, yield, and weed control. the investigation consisted of three factors, i.e., weed control treatments: weedy check (no weeding) and bispyribac-sodium wp @ 150 g ha−1, aromatic rice varieties: kalizira and brri dhan37 and spacing: 20 cm × 15 cm, 25 cm × 15 cm, 20 cm × 20 cm, and 25 cm × 25 cm in a split-split plot design with three replications. thirteen dissimilar types of weeds invaded the experimental plots. among them, monochoria vaginalis was the most prevalent weed at 30 and 60 dat (24.67 and 19.67 weed population m−2 and 15.24 and 13.02% relative weed density sequentially). among all the factors, the application of bispyribacsodium wp (w1), brri dhan47 (v2, grain yield 2.99 t ha−1) and 20 cm × 20 cm (s3, grain yield 2.87 t ha−1) spacing provided promising results. according to the findings, brri dhan37 planted at 20 cm × 20 cm spacing, along with the suggested application of bispyribac-sodium wp could provide the best result. introduction bangladesh, an agrarian country with a large population, relies heavily on profound rice (oryza sativa l.) cultivation. according to bbs (2022), bangladesh’s agricultural sectors accounted for 11.66% of the country’s gdp in the fiscal year 2021-2022. the total area covered by aman rice was speculated to be 5625907 hectares, 0.87% greater than the financial year 2019-2020. in 2020, 4.44 million hectares of cultivable land were accustomed to hyv varieties, 0.75 million hectares for local varieties, 0.31 million hectares for b. aman, and 0.24 million hectares for hybrid varieties. a total of 5.71 million hectares of land were covered by the aman crop (magzter, 2021). however, as per the statistical yearbook bangladesh (bbs, 2022), aman rice was cultivated for 34.11% of the gross area, and the production was 14959 mt. aromatic rice, known as basmati in india, jasmine in thailand, and kataribhog in bangladesh, has a 15-fold higher amount of 2-acetyl-1-pyrroline (2ap) (singh, 2000). scented rice varieties in bangladesh are conventional, photoperiod-sensitive and cultivated during the aman season. despite low yields, these cultivars generate higher turnover due to low cultivation costs (tanchotikul and hsieh, 1991). weeds are undesired plants that grow in locations where they are not deliberately cultivated. according to ramana et al. (2014), weeds pose the greatest drawback to agricultural productivity, with losses ranging from 30 to almost 100%. according to rao et al. (2007), weeds had a devastating effect on crop production caused loss of 32% across the globe. when weeds existed, the grain production of t. aman, boro, and aus rice were lessened by 70–80, 30, and 36%, respectively, prompting increased use of herbicides for chemical weed control (brri, 2008). 57 bushra et al. weed management in sustainable rice production is burdensome due to arduous and expensive physical and cultural methods. at the same time, chemical control is more inexpensive and less timeconsuming, making it more likable over time. the study intends to ascertain the effectiveness of a post-emergent herbicide and spacing in weed management and contrast the competitiveness of local and contemporary aromatic rice varieties in bangladesh. materials and methods site characteristics the study was carried out in the agronomy field of sher-e-bangla agricultural university in dhaka, 8.6 m above sea level and geographically located between 23°77ʹ n latitude and 90°33ʹ e longitude during the period from july 1 to december 20, 2019. it is situated in the agro-ecological zone of the madhupur tract, aez-28, a complex terrain area encompassed by sediments from floodplains, including red soil hillocks from islands. the soil utilized in the experiment was a silty clay loam with an ece of 25-28 and a ph of 5.8-6.5. specimens of soil were taken at depths of 0 to 15 cm. the atmospheric condition in the region was subtropical, with high temperature, humidity, and precipitation. experimental design and treatments three variables were included in this experiment: aromatic rice varieties (v1 and v2), weed control treatments (w0 and w1) and spacings (s1, s2, s3, and s4). the seeds of kalizira (v1) and brri dhan37 (v2) were procured from brri (bangladesh rice research institute) located in joydebpur, gazipur, after undergoing a typical selection process to ensure their health and absence of illness. a post-emergent herbicide called xtra power 20 wp (sodium 2,6-bis[(4,6-dimethoxypyrimidin2-yl)oxy]benzoate, w1) was used in the experiment, which was registered by aci crop care and applied on august 23, 2019, at the rate of 150 g ha−1. it averts the synthesis of plant amino acids through being fastidious, systematic, and absorbed by the foliage and roots. due to its minimal mammalian toxicity and great activity at modest treatment rates, this herbicide has gained popularity (de et al., 2014). the herbicide was administered through a knapsack sprayer, maintaining a 4-5 cm water level for 65-70 days following transplanting at the rate of 150 g ha−1. the other weed control treatment was w0 for which we applied no herbicides. the spacings were 20 cm × 15 cm, 25 cm × 15 cm, 20 cm × 20 cm, and 25 cm × 25 cm which were denoted by s1, s2, s3, and s4 consecutively. for weed treatment and variety, the investigation used a split-split plot design with three replications, having a unit plot size of 5.04 m2 (2.8 m × 1.8 m). n, p, k, s, and zn were supplied to rice plants by urea (150 kg ha−1), triple superphosphate (100 kg ha−1), muriate of potash (70 kg ha−1), gypsum (60 kg ha−1) and zinc sulfate (10 kg ha-1). the amounts of fertilizer used followed the criteria brri provided for cultivating t. aman rice. three split applications were made for urea: 21 dat, 45 dat as top dressing, and 60 dat at the panicle initiation stage. all other fertilizers were applied in basal doses during final land preparation. data collection and calculations to better understand weed interference, the study identified specific weed species and counted their population in a weedy check plot of 1 m2 listed at 30 and 60 dat. the weeds were uprooted, and the fresh and dry weight, relative weed density, weed control efficiency, and weed control index were measured by applying the following formulas: rwd (%) = number of individuals of same species number of individuals of all species ×100 wce (%) = weed population in control-weed population in treated plot weed population in control ×100 wci (%) = weed dry weight in control-weed dry weight in treated plot weed dry weight in control ×100 effect of bispyribac-sodium and spacing on the weed control of rice 58 grain yield was adjusted to 14% moisture, sun-dried, and weighed carefully. after measuring the dry weight of grains in a central 1 m2 area, the final grain yield was recorded for each plot and then converted to t ha−1. grain yield was calculated using the following formula: grain yield (t ha−1)= grain yield per unit plot (kg) × 10000 area of unit plot in square meter × 1000 an arbitrary sample of 1000cleaned dried seeds was weighed using a digital electric balance at 12% moisture, and the mean weight was expressed in grams. results and discussion in the experiment field, the names and populations of individual weed species were noted at 30 and 60 dat on a pre-marked area of 1 m2 of weedy check plots. thirteen different weed species were heeded, with broadleaf and sedge weeds prevailing. the findings comprise 7 broad leaf weeds and 3 grass and sedge weeds each. the result is tabulated below: table 1. weed flora of the experiment field data on the species-specific weed population (no. m−2) and relative density (%) were recorded in the experiment area after 30 and 60 dat, and monochoria vaginalis was found to be predominant. cyperus rotundus followed it, and sagittaria guayansis was the least prominent, with scirpus maritimus and marsilea quadrifolia at 30 and 60 dat subsequently. table 2. weed population by species (no. m−2) and relative weed density (%) in the experimental area at 30 and 60 dat scientific name weed population (no. m−2) relative weed density (%) 30 dat 60 dat 30 dat 60 dat monochoria vaginalis 24.67 19.67 15.24 13.02 cyperus rotundus 20.21 18.86 12.48 12.48 sagittaria guayansis 19.1 17.85 11.80 11.81 cyperus diformis 18.08 15.34 11.17 10.15 ludwigia octovalvis 14.34 14.23 8.86 9.42 sphenoclea zeylanica 13.44 12.34 8.3 8.17 enydra fluctuans 12.5 11.45 7.72 7.58 local name english name scientific name family habitat weed type shama barnyard grass echinochloa cruss-galli poaceae annual grass choto shama jungle rice echinochloa colona poaceae perennial grass chapra indian goosegrass eleusine indica poaceae annual grass cechra dwarf club-rush scirpus maritimus cyperaceae perennial sedge holde mutha yellow nutsedge cyperus diformis cyperaceae perennial sedge mutha java grass cyperus rotundus cyperaceae perennial sedge chondro mala water snowflake nymphoides cristatum menyanthaceae perennial broadleaf helenca buffalo spinach enydra fluctuans asteraceae annual broadleaf jheel-morich gooseweed sphenoclea zeylanica sphenocleaceae annual broadleaf pani kochu pickerel weed monochoria vaginalis pontederiaceae perennial broadleaf pani long mexican primrose willow ludwigia octovalvis onagraceae perennial broadleaf shusni shak european water clover marsilea quadrifolia papayeraceae perennial broadleaf chad mala duckweed sagittaria guayansis alismataceae perennial broadleaf 59 bushra et al. echinochloa colona 11.66 11.5 7.2 7.61 eleusine indica 8.33 7.54 5.15 4.99 nymphoides cristatum 7.8 9.1 4.82 6.02 echinochloa cruss-galli 5.34 4.35 3.3 2.87 marsilea quadrifolia 3.3 3.34 2.04 2.21 scirpus maritimus 3.1 5.54 1.92 3.67 total weed 161.87 151.11 100 100 presence of weeds m−2 in different weed control treatments different weed-control treatments have various impacts on the number or population of weeds. among the different treatments, herbicide-based weed control (w1) reduced weed m−2 at different dat levels. fig. 1. presence of weeds m−2 ; here, w0: weedy, w1: weeds control the population or quantity of weeds was impacted by 2 different weed control techniques at varying dats. the study revealed that the weedy check plots had the highest weed density, with 13.89 and 11.85 weeds m−2 at 30 and 60 dat, respectively. contrarily, the bispyribac-sodium wp plots had the lowest density, with only 6.35 and 7.04 weeds m−2. 1. 33 0. 7 0 2. 33 2 0 0 0 0. 6 0 3 1 1. 33 0. 8 0 0 2 0 0 0 0 0. 33 1 1. 33 0. 8 0. 5 0 0.5 1 1.5 2 2.5 3 3.5 at 30 dat w0 w1 1 0. 6 1 0 0 2 0 0 1. 33 0 2. 33 2 2 0. 33 0 0. 33 0 0 0 0 0 1 1 0 0 0 0 0.5 1 1.5 2 2.5 3 3.5 at 60 dat w0 w1 effect of bispyribac-sodium and spacing on the weed control of rice 60 fig. 2. weed density m-2 .here, w0: weedy, w1: weeds control. presence of weeds m-2 in different rice varieties rice variety treatments affected weed numbers. brri dhan37 (v2) was a particular rice variety that functions well by lessening weed m−2 at different dats. it had the lowest weed density, as competing rice varieties with finer vigor are more productive in repressing weed infestation. fig. 3. varieties of rice with weed m−2 .here, v1: kalizira, v2: brri dhan37. the study was found that weed m−2 significantly influenced rice varieties at different time intervals (dat). kalizira had the highest weed densities (10.84 and 9.69 m−2), and brri dhan37 (v2) had the lowest (9.40 and 9.20 m−2). fig. 4. effect of variety on weed density m−2 at different dat.here, v1: kalizira, v2: brri dhan37. presence of weeds m−2 in different spacing: as per the column chart, the maximum weed density was recorded at 25 cm × 25 cm spacing, s4, and the lowest at 20 cm × 20 cm, s3. we can conclude that the prevalence of weeds and the requirement for herbicides can be lessened with the s3 spacing, as it can provide shading and lower weeds’ competing abilities. 13 .8 9 11 .8 5 6. 35 7. 04 0 5 10 15 dat 30 dat 60 w ee d de ns ity m -2 w0 w1 1 2 0 1. 33 1 1 0 1 1 1 2. 33 2 2 1. 33 0 0 0 0 0 0 0. 33 1. 33 0. 33 1 0. 33 1 0 0.5 1 1.5 2 2.5 3 3.5 at 60 dat v1 v2 10 .8 4 9. 69 9. 4 9. 2 8 8.5 9 9.5 10 10.5 11 dat 30 dat 60 w ee d de ns ity m −2 v1 v2 1 1 0 1 2 0 0 0 0. 33 0 0. 33 3 2. 33 0. 33 1 0 1. 33 1 1 0 0 1 1 0 0 0 0 0.5 1 1.5 2 2.5 3 3.5 at 30 dat v1 v2 61 bushra et al. fig. 5. presence of weeds m−2 in different spacing. here, s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm and s4: 25 cm × 25 cm. the experiment also revealed that varying spacing significantly impacted weed density at various dats, with maximum density in 25 cm × 25 cm (s4) and minimum in 20 cm × 20 cm (s3). fig. 6. effect of spacing on weed density m−2 at different dats. weed control efficiency the weed control efficiency stretched from 19.34% to 27.88% over the weedy check plot, which is attributable to the different rice varieties used in the experiment. the cultivation of brri dhan37 (v2) resulted in the foremost weed control efficiency at both 30 and 60 dat, with a percentage of 27.88% and 21.09%, respectively. 1. 33 1 0 1 1 1 0 1 0 0 0 2 1. 33 1 0 1 1 1 1 1 0 1 1 1 1 1 0. 33 0 0. 33 0 0 0. 33 0 0 0 0 1. 66 0. 33 11 2 0 0 0 2 1. 33 1 1. 33 1 1 2 2 0 0.5 1 1.5 2 2.5 3 3.5 at 30 dat s1 s2 s3 s4 1 0 1 2 1 1 0 1 0 0 2 2 1 0. 33 1 0 1 1 1 1 1 2 0. 33 1 1 1 0 0 0. 33 0. 33 0 0 0 0 0. 33 0 0 0. 33 1. 33 1 2 0 1. 33 0. 33 1. 33 0. 33 0. 33 3 1 0. 33 1 2 0 0.5 1 1.5 2 2.5 3 3.5 at 60 dat s1 s2 s3 s4 9.91 10.17 8.63 11.76 9.36 9.5 8.66 10.25 0 2 4 6 8 10 12 14 at 30 dat s1 s2 s3 s4 at 60 dat s1 s2 s3 s4 effect of bispyribac-sodium and spacing on the weed control of rice 62 fig. 7. effect of variety on weed control efficiency. aromatic rice cultivated at 20 cm × 20 cm (s3) spacing recorded the highest weed control efficiency (29.27% and 22.98%) at 30 and 60 dat, which was statistically identical to the result when it was cultivated at 20 cm × 15 cm (s1) spacing (29.09%) at 30 dat. fig. 8. effect of spacing on weed control efficiency. here, s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm. and s4: 25 cm × 25 cm. weed control index the weed control index of aromatic rice at 30 and 60 dat is remarkably affected by the varieties of rice used. it ranged from 16.32% to 30.40% over the weedy check plot. the experiment revealed that brri dhan37 (v2) recorded the maximum weed control index (30.40% and 28.81%), while kalizira (v1) recorded the minimum weed control index (24.46% and 16.32%) at 30 and 60 dat. 26.68 19.34 27.88 21.09 0 5 10 15 20 25 30 dat 30 dat 60 w ee d co nt ro l e ffi ci en cy (% ) v1 v2 29.09 19.86 25.86 19.71 29.27 22.9824.88 18.32 0 5 10 15 20 25 30 35 dat 30 dat 60 w ee d co nt ro l e ffi ci en cy (% ) s1 s2 s3 s4 24.46 16.32 30.4 28.81 0 10 20 30 40 dat 30 dat 60w ee d co nt ro l i nd ex (% ) v1 v2 63 bushra et al. fig. 9. effect of variety on weed control index. the highest weed control index was achieved when aromatic rice was cultivated at 20 cm × 20 cm (s3) spacing with weed control indices of 30.20% and 23.92% and cultivation at a spacing of 25 cm × 25 cm (s4) resulted in the minimum weed control index of 21.69% and 20.24% at 30 and 60 dat respectively. fig. 10. effect of spacings on weed control index. here, s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm and s4: 25 cm × 25 cm. combined effects the study examined the collective effect of weed control and rice variety, spacing and their interaction effect on the weed population in the aman rice field. the study revealed that using bispyribacsodium wp @ 150 g ha−1 in combination with brri dhan37 (w1v2) cultivation culminated in the lowest weed density at both time parameters. table 3. effects of variety and weed management combined on weed density treatment combinations weeds density m−2 dat 30 dat 60 w0v1 14.75 ± 1.32a 12.00 ± 1.08a w0v2 13.02 ± 1.62b 11.69 ± 0.72b w1v1 6.93 ± 1.31c 7.38 ± 1.15c w1v2 5.77 ± 0.93d 6.71 ± 0.48d se± 0.04 0.14 cv (%) 1.94 2.28 the weed density was even lower when the herbicide was used with narrow spacing (20 cm × 20 cm). ultimately, the soundest method for curtailing weed density was using the herbicide with brri dhan37 cultivation and narrow spacing (20 cm × 20 cm). table 4. effects of weed control, variety, and spacing combined on weed density treatment combinations weeds density m−2 dat 30 dat 60 w0v1s1 13.00 ± 0.68d 11.67 ± 0.52b w0v1s2 15.00 ± 0.79c 12.00 ± 0.63b w0v1s3 15.00 ± 0.78c 11.67 ± 0.61b w0v1s4 16.00 ± 0.84a 12.67 ± 0.65a w0v2s1 11.34 ± 0.59f 9.98 ± 0.61c w0v2s2 12.44 ± 0.65e 11.67 ± 0.61b w0v2s3 13.00 ± 0.68d 12.67 ± 0.67a w0v2s4 15.30 ± 0.81b 12.44 ± 0.65a 28.07 23.82 29.77 22.29 30.2 23.9221.69 20.24 0 5 10 15 20 25 30 35 dat 30 dat 60 w ee d co nt ro l i nd ex (% ) s1 s2 s3 s4 effect of bispyribac-sodium and spacing on the weed control of rice 64 w1v1s1 5.37 ± 0.28k 6.67 ± 0.33fg w1v1s2 7.13 ± 0.38h 7.00 ± 0.37ef w1v1s3 6.47 ± 0.34i 6.77 ± 0.37f w1v1s4 8.74 ± 0.46g 9.06 ± 0.48d w1v2s1 5.17 ± 0.27k 6.34 ± 0.33g w1v2s2 6.10 ± 0.32j 7.33 ± 0.39e w1v2s3 4.80 ± 0.25l 6.33 ± 0.33g w1v2s4 7.01 ± 0.37h 6.84 ± 0.36f se± 0.08 0.28 cv (%) 1.39 2.43 note viz: ns=nonsignificant; w0:weedy check and w1: bispyribac-sodium wp @ 150 g ha-1; v1: kalizira and v2: brri dhan37; s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm and s4: 25 cm × 25 cm bispyribac sodium wp @ 150 g ha−1 herbicide-treated plot along with brri dhan37 cultivation at 20 cm × 20 cm spacing recorded the maximum weed control efficiency (60.23% and 49.96%) at 30 and 60 dat respectively. table 5. the combined effect of weed control, variety, and spacings on weed control efficiency and weed control index of aromatic rice at different dat treatment combinations weed control efficiency weed control index dat 30 dat 60 dat 30 dat 60 w0v1s1 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v1s2 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v1s3 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v1s4 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v2s1 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v2s2 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v2s3 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w0v2s4 0.00 ± 0h 0.00 ± 0f 0.00 ± 0h 0.00 ± 0h w1v1s1 58.69± 1.17b 42.85± 0.73c 47.64± 0.95f 36.49 ± 0.46e w1v1s2 52.47 ± 1.05e 41.67 ± 0.83c 55.63 ± 1.11d 32.62 ± 0.65f w1v1s3 56.87± 1.14c 41.98 ± 0.84c 54.98 ± 1.1d 30.96 ±0.62fg w1v1s4 45.38 ± 0.91g 28.27 ± 0.53e 37.46 ± 0.75g 30.51 ±0.61g w1v2s1 57.67 ± 1.15c 36.57 ± 0.86d 64.65 ± 1.29b 58.78 ±0.97b w1v2s2 50.95 ± 1.02f 37.19 ± 0.74d 63.46± 1.27c 56.55 ±1.13c w1v2s3 60.23 ± 1.2a 49.96 ± 0.99a 65.80 ± 1.32a 64.73± 1.15a w1v2s4 54.15 ± 1.24d 45.00 ± 0.89b 49.30 ± 0.99e 50.44± 1.1a se± 0.71 0.87 1.09 1.17 cv (%) 1.94 6.11 2.04 4.63 a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at 0.05 probability level. note viz: ns=nonsignificant; w0:weedy check and w1: bispyribac-sodium wp @ 150 g ha-1; v1: kalizira and v2: brri dhan37; s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm and s4: 25 cm × 25 cm grain yield and 1000‐grain weight rice varieties have a significant impact on grain yield, with the brri dhan37 (v2) rice variety achieving a maximum yield (2.99 t ha−1) due to its higher filled grains per panicle and 1000 grain weight (17.56 g). 65 bushra et al. fig. 11. effect of variety on grain yield and 1000‐grain weight. here, v1: kalizira and v2: brri dhan37. the study also found that spacing significantly affects the grain yield of aromatic rice. the maximum yield and 1000‐grain weight were recorded at the spacing of 20 cm × 20 cm (s3, 2.87 t ha−1 and 16.68 g respectively), followed by 25 cm × 15 cm, and lowest in 25 cm × 25 cm (s4) in both parameters. fig. 12. effect of spacing on grain yield and 1000−grain yield. here, s1: 20 cm × 15 cm, s2: 25 cm × 15 cm, s3: 20 cm × 20 cm, s4: 25 cm × 25 cm conclusion the study was led to investigate the consequences of a post-emergent herbicide and spacing on the weed control and growth of two aromatic rice varieties that are extensively cultivated in bangladesh. among different treatments, bispyribac-sodium wp @ 150 g ha−1 herbicide-treated plots (w1) were reported as having the minimum weed density m−2 (6.35 and 7.04 m-2) at 30 and 60 dat. rice varieties notably affected weeds, and brri dhan37 (v2) was perceived as having the minimum weed density m−2 (9.40 and 9.20 m−2) at 30 and 60 dat. in terms of spacing, 20 cm × 20 cm (s3) was proven to be outstanding. to conclude, it was recorded that cultivation of brri dhan37 along with bispyribac-sodium wp @ 150 g ha−1 and a spacing of 20cm × 20cm influenced the outcome appreciatively. however, further trials with the same treatment combination in separate locations in bangladesh would be more useful before delivering a closing statement. references bbs (bangladesh bureau of statistics). 2023. statistical yearbook bangladesh 2022. bangladesh bureau of statistics, ministry of planning. dhaka. bangladesh. brri (bangladesh rice research institute). 2008. annual report for 2007. bangladesh rice research institute, joydevpur, bangladesh. pp. 28–35. de, a., r. bose, k. ajeet and s. mozumdar. 2014. targeted delivery of pesticides using biodegradable polymeric, nanoparticles. springer, new delhi, india. pp. 978-981. magzter. 2021. business standard newspaper. september 16, 2020. pp. 1-2. https://www.magzter.com/in/business-standard-private-ltd/businessstandard /newspaper/519197. ramana, a.v., d.s. reddy and k. ramakumar. 2014. influence of sowing time and nitrogen levels on growth, yield and n uptake of rainfed upland rice varieties. andhra agril. j. 54(3&4): 114–120. rao, a.n., i.j. johnson, b. sivaprasad, j.k. ladha and a.m. mortimer. 2007. weed management in direct seeded rice. adv. agron. 93: 153–255. singh, r.k. 2000. genetics and biotechnology of quality traits in aromatic rices. in: r.k. singh, us. singh, g.s. khush, rashmi rohilla (eds.). aromatic rice. oxford & ibh publishing co. pvt. ltd., new delhi. pp.47 tanchotikul, u. and t.c.y. hsieh. 1991. an improved method for quantification of 2-acetyl-1-pyrroline a popcornlike aroma, in aromatic rice by high-resolution gas chromatography/mass chromatography/selected ion monitoring. j. agric. food chem. 39(5): 944-947. bangladesh agron. j. 2025, 28(1): 29-34 intercropping of summer onion with mukhikachu m. a. h. khan1*, m. rahman2, t. husna2, s. akther1, m. j. islam3 1agronomy division, bangladesh agricultural research institute, gazipur 2regional agricultural research station, bangladesh agricultural research institute, cumilla 3upazila agriculture office, barura, cumilla *corresponding author, email: ayubagronomy@yahoo.com (received: 14 october 2025, accepted: 21 november 2025) keywords: intercrop, mukhikachu, summer onion abstract an experiment was conducted at the research field of regional agricultural research station (rars), bangladesh agricultural research institute (bari), cumilla during kharif i, 2022 to find out the suitable combination of onion with mukhikachu for increasing total productivity, economic return and maximize land utilization through intercropping system. seven treatments viz., i) sole mukhikachu ii) two rows of summer onion in between two rows of mukhikachu iii) three rows of summer onion in between two rows of mukhikachu iv) two rows of summer onion in between two double rows of mukhikachu v) three rows of summer onion in between two double rows of mukhikachu vi) sole summer onion. the trial was set up in a randomized complete block design with three replications. the unit plot size was 3.0 m × 2.70 m. the mukhikachu was (var. bari mukhikachu-1) a main crop and onion (var. bari peaz-5) were used as intercrops in the study. the sole crop of mukhikachu was planted at a spacing of 60 cm × 45 cm, the sole crop of onion at a spacing of 15 cm × 10 cm. results showed that, different intercropping combination significantly influenced yield and yield contributing characters of mukhikachu. the yield of mukhikachu was comparatively lower in intercropping than sole mukhikachu but total productivity was increased due to additional yield of onion. increased total productivity in terms of mukhikachu equivalent yield (mey) was 38.72-42.28 t ha−1 in intercrop combination compared to sole mukhikachu 31.70 t ha−1 (main crop). all the intercropping combinations showed better performance in terms of mukhikachu equivalent yield, gross return and benefit cost ratio (bcr) over sole crops. among the intercropping combinations three rows of onion in between two double rows of mukhikachu was the most feasible intercropping system in respect of mukhikachu equivalent yield (42.28 t ha−1), gross return (tk.8,45600), gross margin (tk. 5,18100) and benefit cost ratio (2.58). three rows of summer onion in between two rows of mukhikachu (bcr 2.56) and two rows of summer onion in between two double rows of mukhikachu (bcr 2.51) were also feasible intercrop combination. introduction intercropping is a common practice of crop cultivation to increase the productivity per unit area and ensure against total crop failure under aberrant weather condition. it increases total productivity per unit area through maximum utilization of land, labor and growth resources. it also increases land equivalent ratio (ler) to a varying degree (hossain and bari, 1996). successful intercropping system gives higher cash return, total production per hectare and diversifies production system than sole cropping and provides greater resources use efficiency. yield advantage in intercropping are mainly due to efficient utilization of resources such as light, water and nutrients than respective sole crop (liu et al., 2006). other potential benefits of intercropping include high productivity and profitability (yildirim and guvence, 2005), increase in soil fertility through nitrogen fixation by addition of leguminous crop in intercropping system (hauggaardmailto:ayubagronomy@yahoo.com 30 khan et al. nielsen et al., 2001), reducing damage caused by pests, weeds and diseases (banik et al., 2006), improvement of quality of forage (barillot et al., 2014) and use of environmental resources efficiently (eskandari and ghanbari, 2010). onion (allium cepa) is one of the most important spices as well as vegetable crops of bangladesh. it is widely cultivated during winter season. but now-a-days some onion varieties are also cultivate in summer season. summer onion cultivation can be a new way to increase the onion production in bangladesh and make it available throughout the year. consequently, demand of onion will be met up and employment opportunity will be created. this crop may be harvest within very short time. onion could be cultivated in between two rows of mukhikachu as an extra or inter-crop. mukhikachu (colocasia esculenta var. globulifera l.) is an important edible aroid in bangladesh as well as in some other countries of the world. it occupies about 80% of the total aroid production in the country (bhuiyan and ahmed, 2001). mukhikachu is rich in vitamin a, c, iron and calcium. in bangladesh, it comes to market as an important summer vegetable when most of the vegetables are not available. it plays a vital role to meet up the demand of vegetables in the lean period. after plantation, the crop requires six months for shoot growth. then it declines and cormel growth starts and continues to grow about 2 to 3 months till maturity, in this condition 8-9 months are required for cultivation of mukhikachu. the rate of mukhikachu emergence and subsequent growth are very slow. the emergence starts at 25-30 days after planting and it continues up to 50 to 60 days. its growth becomes rapid at later stage when soil moisture is sufficient by rainfall. intercropping of summer onion with mukhikachu is a way to avoid direct competition with other crops and to familiarize its potentiality to the farmers. summer onion being a short duration (70-80 days) crop can be intercropped easily with long duration (210-280 days) wider spaced mukhikachu. they have also different growth habit and demand for growth resources. the return from intercropping is higher and more profitable than those from the relevant sole crops. so, if mukhikachu and summer onion can be grown as intercrop, the farmers may be benefited economically. the findings on intercropping mukhikachu with summer onion and their suitable ratio is not available. hence, an experiment was undertaken to find out the suitability of intercropping summer onion with mukhikachu for higher productivity and profitability at varying combinations. materials and methods a field experiment has been conducted at research field of regional agricultural research (rars) station, bangladesh agricultural research institute (bari), cumilla during kharif i 2022. the treatments were: i) sole mukhikachu ii) two rows of summer onion in between two rows of mukhikachu iii) three rows of summer onion in between two rows of mukhikachu iv) two rows of summer onion in between two double rows of mukhikachu v) three rows of summer onion in between two double rows of mukhikachu vi) sole summer onion. bari mukhikachu-1 (main crop) and bari peas-3 (component crop) were used as variety. the trial was set up in a randomized complete block design (rcbd) with three replications. the unit plot size was 3.0 m × 2.70 m. sole mukhikachu and intercrop treatments were fertilized with n-p-k-s 96-27-81-18 kg ha-1 respectively. full amount of pks was applied as basal. n was applied in two equal splits, one at 20 days after planting (dap) and another at 45 dap. the sole crop of normal mukhikachu was planted at a spacing of 60 cm × 45 cm, in case of double rows mukhikachu was planted 55 cm × 20 cm × 45 cm. mukhikachu was planted on 14 march 2022. forty days old onion seedling was transplanted on 16 march 2022. the onion seedling was transplanted at a spacing of 15 cm × 10 cm. irrigation and pesticide were applied as per necessary. weeding was done at 25, 45 and 60 days after transplanting. intercropping of summer onion with mukhikachu 31 for, mukhikachu data on yield and yield contributing characters were taken and analyzed statistically. the yield component data of mukhikachu and onion was taken from 10 randomly selected plants prior to harvest from each plot. for mukhikachu and onion at harvest the yield data were recorded plot wise. the collected data were analyzed statistically using statistix 10 package and means were adjudged by lsd at 5% level of probability. mukhikachu equivalent yield (mey) was converted by converting yield of intercrops on the basis of market price of individual crop following the formula: mukhikachu equivalent yield = yield of intercrop mukhikachu + 𝑌𝑖 ×𝑃𝑖 price of mukhikachu where, yi = yield of intercrop (onion) and pi = price of intercrop (onion). land equivalent ratio (ler) values were determined from the yield data of the crops by the following equation: ler = 𝑌𝑖𝐶 y syc + 𝑌𝑖𝑐𝑐 ysycc where, yic= intercrop yield of mukhikachu ysyc = sole yield of mukhikachu yicc = intercrop yield of component crop (onion) ysycc = sole yield of component crop (onion) results and discussion yield and yield attributing characters of mukhikachu plant height, number of corm plant−1, corm weight plant−1, number of cormel plant−1, cormel weight plant−1 and yield were significantly influenced due to sole and intercropping onion with mukhikachu (table 1). the highest plant height (112.33) was obtained from t1 and the lowest (103.33 cm) was found in t2 treatment. the highest number of corm plant−1 (10.8), and cormel plant−1 (30.2) was recorded in (t5) treatment. the highest cormel wt. plant−1 (517.5 g) was obtained from sole mukhikachu (t1) which was statistically similar with t5 (515.0 g) and t4 (512) treatment. the highest yield (31.70 t ha−1) was obtained from t1 treatment and the lowest (28.80 t ha−1) was observed from t2 treatment. islam et al. (2014) also reported similar result. table 1. yield and yield attributes of mukhikachu under sole and intercropping situation during kharif 2022 treatments plant height (cm) corm plant−1 (no.) corm weight plant−1 (g) cormel plant−1 (no.) cormel weight plant−1 (g) yield (t ha−1) t1 112.33 8.87 488 29.0 517.5 31.70 t2 103.33 8.13 493 25.4 434.0 28.80 t3 107.27 9.73 507 27.6 468.7 29.20 t4 108.73 10.2 508 29.8 512.0 30.30 t5 108.47 10.8 471 30.2 515.0 31.00 lsd(0.05) 5.3 2.1 ns 3.2 32.7 2.1 cv(%) 8.4 5.6 9.8 11.2 7.5 9.5 i) t1sole mukhikachu ii) t2two rows of summer onion in between two rows of mukhikachu iii) t3-three rows of summer onion in between two rows of mukhikachu iv) t4two rows of summer onion in between two double rows of mukhikachu v) t5three rows of summer onion in between two double rows of mukhikachu. 32 khan et al. yield and yield attributes of intercrop onion branch plant−1, bulb height, bulb diameter, single bulb weight and yield were significantly influenced due to sole and intercropping onion (table 2). the highest branch plant−1 (6.13 cm) was obtained from t6 and the lowest (5.86 cm) was in t5 treatment. the highest bulb height (5.00 cm) was recorded in t3 treatment which was identical to t4, t5 and t6 treatment. the highest bulb diameter (3.70 cm) was obtained from sole onion (t6) which was statistically similar (3.60) with t2 treatment. the highest single bulb weight (24.93 g) was obtained from sole onion (t6) which was statistically similar (23.73) with t4 treatment and the lowest (22.07 g) was recorded in t2 treatment. the highest onion bulb yield (8.38 t ha−1) was obtained from t6 treatment and the lowest (4.96 t ha−1) was achieved from t2 treatment. the highest yield was obtained might have the effect of the highest single bulb weight in sole crop. islam et al. (2014) also reported similar result. dahmardeh et al. (2009) also observed that yield of intercropping system is often higher than in sole cropping system. table 2. yield of onion under sole and intercropping situation during kharif i 2022 treatments plant height (cm) branch plant−1 (no.) bulb height (cm) bulb diameter (cm) single bulb weight (g) yield (t ha−1) t2 37.13 5.93 4.63 3.60 22.07 4.96 t3 35.33 5.93 5.00 3.37 23.00 6.34 t4 35.40 5.93 4.97 3.50 23.73 5.22 t5 37.33 5.86 4.80 3.33 22.27 5.64 t6 39.20 6.13 4.93 3.70 24.93 8.38 lsd(0.05) ns 0.18 0.22 0.10 1.42 cv(%) 10.5 9.8 8.8 8.7 8.9 5.8 i) t1sole mukhikachu ii) t2two rows of summer onion in between two rows of mukhikachu iii) t3 -three rows of summer onion in between two rows of mukhikachu iv) t4two rows of summer onion in between two double rows of mukhikachu v) t5three rows of summer onion in between two double rows of mukhikachu vi) t6 -sole summer onion. mukhikachu equivalent yield mukhikachu equivalent yield is expressed in total productivity. mukhikachu equivalent yield were higher (38.72 42.28 t ha−1) in all the intercrops than the sole crop of mukhikachu (31.70 t ha−1) and onion (16.76 t ha−1). in intercrop combination, the highest mukhikachu equivalent yield (42.28 t ha−1) was recorded in t5 treatment (three rows of summer onion in between two double rows of mukhikachu) which was followed by (41.88 t ha−1) t3 treatment (three rows of summer onion in between two rows of mukhikachu) and the lowest mukhikachu equivalent yield (16.76 t ha−1) was obtained from t6 treatment (sole onion). ahmed et al. (2013) also reported that intercrop combination increase the equivalent yield. table 3. mukhikachu equivalent yield (mey), land equivalent ratio (ler) and cost and return analysis of mukhikachu and onion under sole and intercropping situation at rars, bari, cumilla treatments mey (t ha−1) ler gross return (tk. ha−1) cost of production (tk. ha−1) gross margin (tk. ha−1) benefit cost ratio (bcr) t1 31.70 1.00 634000 275000 359000 2.30 t2 38.72 1.81 774400 325000 449400 2.38 t3 41.88 2.07 837600 327500 510100 2.56 t4 40.74 1.90 814800 325000 489800 2.51 t5 42.28 2.00 845600 327500 518100 2.58 t6 16.76 1.00 335200 165000 170200 2.03 cey= chilli equivalent yield; ler= land equivalent ratio, i) t1sole mukhikachu ii) t2-two rows of summer onion in between two rows of mukhikachu iii) t3 -three rows of summer onion in between two rows of mukhikachu iv) t4two rows of summer onion in between two double rows of mukhikachu v) t5three rows of summer onion in between two double rows of mukhikachu vi) t6 -sole summer onion. intercropping of summer onion with mukhikachu 33 cost benefit analysis intercropping combination of onion with mukhikachu showed higher monetary return than sole crop (table 3). the highest gross return (tk. 8,45600) was recorded from t5 treatment (three rows of summer, onion in between two double rows of mukhikachu) which was 33.3% higher than the sole mukhikachu. this intercropping combination (t5) also gave the higher gross margin (tk. 5,18100) and benefit cost ratio (2.58) followed by t3 treatment (three rows of summer onion in between two rows of mukhikachu) with 2.56 bcr. the results of increased productivity and returns were consistent with the earlier reports of yield advantages of crop mixture compared to monoculture (islam et al., 2012 and ahmed et al., 2013). munir et al. (2004) also observed that higher net income and benefit cost ratio was observed in wheat gram intercropping system. conclusion the result revealed that, all intercropping treatments were productive as compared to sole treatments. among the treatments, t5 onion with mukhikachu combination (three rows of summer onion in between two double rows of mukhikachu) were more productive and profitable in respect of cey and monetary return. three rows of summer onion in between two rows of mukhikachu (t3) and two rows of summer onion in between two double rows of mukhikachu (t4) combinations were also profitable in respect of mey and bcr. acknowledgment the authors are greatly thankful to the “upgrading regional horticulture research station, cumilla to regional agricultural research station project” for the financial and technical support during the experimentation. references ahmed, f., m.n. islam, m.s. alom, m.a.i. sarker and m.a. mannaf. 2013. study on intercropping leafy vegetables with okra (abelmoschus esculentus l.). bangladesh j. agril. res. 38(1): 137-143. banik, p., a. midya, b.k. sarkar, and s.s. ghose. 2006. wheat and chickpea intercropping systems in an additive series experiment: advantages and weed smothering. eur. j. agron. 24: 325-332. barillot, r., a.j. escobar-gutiérrez, c. fournier, p. huynh and d. combes. 2014. assessing the effects of architectural variations on light partitioning within virtual wheat–pea mixtures. ann. bot., mcu 099. bhuiyan, m.k.r. and m.s. ahmed. 2001. varietal improvement and development of production package of aroids in diversified areas in bangladesh. a final report. contract research project. agricultural research management project (armp) ida credit281 5-bd, bangladesh agricultural research council, dhaka. pp. 1-2. dahmardeh, m., a. ghanbari, b.s. syasar and m. ramroudi. 2009. effect of intercropping maize with cowpea on green forage yield and quality evaluation. asian j. plant sci. 8: 235-239. eskandari, h. and a. ghanbari. 2010. effect of different planting pattern of wheat (triticum aestivum l.) and bean (vicia faba) on grain yield, dry matter production and weed biomass. not. sci. biol. 2: 111-115. hauggaard-nielsen, h., p. ambus and e.s. jensen. 2001. temporal and spatial distribution of roots and competition for nitrogen in pea-barley intercrops. a field studies employing 23 p techniques. plant soil. 236: 63-74. hossain, m.a. and a.k.m.a. bari.1996. effect of intercropping groundnut with garlic at varying plant population levels. bangladesh hort. 24(1-2): 29-34. islam, m.r., m.a.k. mian and m.t. rahman. 2012. suitability of intercropping sesame with mukhikachu leafy vegetables and legumes with brinjal. bangladesh j. agril. res. 37(4): 625-634. 34 khan et al. islam, m.r., m.t. rahman, m.f. hossain and n. ara. 2014. feasibility of intercropping leafy vegetables and legumes with brinjal. bangladesh j. agril. res. 39(4): 685-692. liu, j.h., z.h. zeng, l.x. jiao, y.g. hu, y. wang and h. li. 2006. intercropping of different silage maize cultivars and alfalfa. acta. agron. sci. 32: 125-130. munir, m., m. saeed and m. imran. 2004. crop productivity and net return in wheatgram intercropping. pakistan j. agric. res. 18: 20-24. yildirim, e. and i. guvence. 2005. intercropping based on cauliflower: more productivity, profitable and highly sustainable. eur. j. agron. 22: 11-18. bangladesh agron. j. 2021, 24(1): 1-11 sustainability of wheat (triticum aestivum l.) yield and improvement of seed quality through probiotic and organic soil amendment m.a. hossain1, 2, s.m.s. islam1 and m.m. hasan3 1plant biotech.& genetic eng. lab., inst. of biol. sci., university of rajshahi 2directorate of secondary and higher education, dhaka-1000 3plant path. lab., agron. & agril. extn. dept., university of rajshahi corresponding e-mail:mahmudul742001@yahoo.com (received: 27 november 2020, accepted: 31 january 2021) keywords: poultry manure, vermicompost, green manure, yield, seed quality, wheat abstract in search of alternative counter to harmful effects of chemical fertilizers on soils and environment, probiotic and organic manures-based fertilizer management options need to be evaluated. the experiments were designed as randomized complete block design (rcbd) consisting of three wheat varieties and nine soil amendment treatments. the result revealed that organic amendments had prominent and variable effects on studied parameters and statistically at par with chemical fertilizer. some yield-associated parameters like spike length, spikeletsspike-1, fertile spikelets spike-1, grains spike-1, grains weight spike-1 and 1000-grain weight were significantly influenced by organic amendments. moreover, grain yield and straw yield were increased73% and 27%, respectively under the treatment of poultry manure combination in comparison with control. in addition, the seed quality characters viz. germination, vigor index and total soluble protein content also exhibited significant improvement showing23%, 44%and 17%, respectively by poultry manure + vermicompost + green manure. the above findings showed that to apply poultry manure + vermicompost + green manure as an effective soil amendment option and to obtain good yield and quality seed of wheat. introduction in bangladesh, wheat occupies 4% of the total cropped area and 11% of the cropped area in the rabi season and contributes 7% to the total output of food cereals (bbs, 2008). in bangladesh, the average yield of wheat is 3.16 t ha-1 (bbs, 2017), which is below the achievable yield of 4.5 t ha-1 (bari, 2011). alam et al. (2013) stated two reasons for the yield gap as (i) biotic factors including poor quality seeds and seedlings, insects, diseases, weeds and rodents; and (ii) abiotic factors including soil, nutrients and water. however, many reasons for this yield gap remain unexplained. nutrients availability of soils is declining with time pace but which had been rich in the past. among the different agricultural inputs, fertilizer is the most important one and nearly 50% of the modern agricultural production depends on this insert (pradhan, 1992). the non-judicial and imbalanced use of chemical fertilizer generate hazards on soil, environment and human health which led the growers’ considerable attention to turn organic manures application for sustainable production practices (singh et al., 2018). it is authentic that fairly good soil fertility and plant nutrients are important to farming, whether the practices are considered “conventional” or “sustainable” (hue and silva, 2000). yadvinder-singh mailto:mahmudul742001@yahoo.com 2 hossain et al. et al. (2008) stated organic materials like crop residues, green manure, and animal manure show great influence on soil productivity. therefore, probiotic and organic manures application should be evaluated on agricultural land reclamation and crop yield potentiality aspects in bangladesh. in this view, the investigation was carried out to assess the effect of probiotic and organic manure amendment soil on the yield and seed quality of wheat. materials and methods the present piece of research work was conducted in the institute of biological sciences (ibs) and plant pathology laboratory, department of agronomy and agricultural extension, university of rajshahi, bangladesh during the period from july 2016 to june 2019. the experimental field is geographically situated at 24º17" n latitude and 88º28" e longitude at an elevation of 20 m above the sea level belonging to the agro-ecological zone-11(aez-11). the soil of the experimental field is characterized by poorly drained with moderate permeable, loamy and slightly alkaline (ph = 8.10) in nature. before 2016, the field was occupied with barley production for two years. the experiment was laid out in randomized complete block design (rcbd) with three replications. three wheat varieties viz. bari gom-28 (v1), bari gom-29 (v2), bari gom-30 (v3)and nine soil amendment treatments viz. control (t0), rice straw + vermicompost + green manure (t1), cow dung + vermicompost + green manure (t2), compost + vermicompost + green manure (t3), poultry manure + vermicompost + green manure (t4), trichoderma harzianum + vermicompost + green manure (t5), mungbean residue + vermicompost + green manure (t6), trichoderma viride + vermicompost + green manure (t7) and chemical fertilizer (t8) were used . the unit plot was 5.0 m2 having the plot to plot 0.5 m, bed to bed 0.25 cm distances and 1m from surrounding the boundary. seeds of dhaincha (sesbania rostrata) were sown at the rate of 50 kg ha-1to the respective plots and after 50 days of sowing young succulent green plants were incorporated into the soil. crop residues (rice straw, mungbean residue), cow dung, compost and poultry litter were applied @ 10 t ha-1 before 7 days of sowing. vermicompost was applied @ 5 t ha-1and trichoderma spp. suspension (1×106 cfu g-1 @ 5 kg ha-1) before sowing. in the case of chemical treatment, one-third of urea (200 kg ha-1), tsp 160 kg ha-1, mop 45 kg ha-1 and gypsum 115 kg ha-1 were used as basal dose (bari, 2014). the rest of the urea was applied as two installments one at 21 das and another at 55 das. data recording in the case of yield and yield attributes, ten spikes were selected randomly from each experimental plot for recording data on spike length, spikeletsspike-1, fertile spikelets spike-1, grains spike-1 and grain weight spike-1, while 1000-grain weight, grain yield and straw yield of crops were recorded which were collected from one square meter area at the center of each unit plot. harvest index (%) the harvest index denotes the ratio of grain yield (economic yield) to biological yield and was calculated with the following formula: harvest index % = grain yield biological yield × 100 here, biological yield= grain yield + straw yield. yield and seed quality of wheat through probiotic and organic soil amendment 3 determination of seed germination four hundred seeds of each treatment were taken for germination test as recommended by ista (1985). germination of seeds was collected regularly for up to 10 days. percentage of germination was determined as follows: germination (%) = no. of germinated seedling no. of seed set for germination × 100 vigor index after setting seeds, the germination percentage was calculated from the final count. vigor index was found out by using the following formula (maguire, 1962): vigor index = no. of normal seedlings first count days to first count + − − − − − − − − + no. of normal seedlings final count days to final count the total soluble protein content of seed a technique formerly defined by guy et al. (1992) was performed with some modification to estimate the total soluble protein of seed using a spectrophotometer. statistical analysis the recorded data were compiled and tabulated for statistical analysis. the trial data for all parameters were analyzed statistically for analysis of variance (anova) throughr-studio (http://www.rstudio.com/) of “agricolae” package (https://cran.r project.org/package=agricolae) and duncan’s multiple range test (dmrt) was performed for comparing treatment means(gomez and gomez, 1984). results and discussion effect of soil amendment on yield and yield attributes spike length the spike length was affected significantly by various soil amendment treatments (table 1). in the final year, it has been found that the treatment t8(chemical fertilizer) produced the maximum spike length (8.60 cm) which was followed byt4(poultry manure + vermicompost + green manure) (8.43 cm) while the smallest spike length recorded from t0 (7.00 cm).it might be due to higher nutrient concentration and moisture retention of the soil amended with poultry manure combination treatment that led to the formation of longer spike length. this result was correlated with ahmed et al. (2002). nevertheless, green manure fortified poultry manure keeps the n balance which may enhanced the length of spike of wheat. the above statement was also supported by nguyen et al. (1995). spikelets spike-1 and fertile spikelets spike-1 the spikelets spike-1 is treated as an important element of wheat grain yield (sabaghina et al., 2014). from table 1, it revealed that spikelets spike-1 varied significantly from 13.80 to 17.97 where the maximum and the minimum value for this parameter were recorded from t8 and t0. http://www.rstudio.com/ https://cran.r-project.org/package=agricolae https://cran.r-project.org/package=agricolae https://cran.r-project.org/package=agricolae 4 hossain et al. nitrogen-rich organic manures may have a positive effect on the growth and yield attributes of wheat where higher fertile spikelet spike-1 from t8 (17.24) and t4 (17.00) but 13.22 was the lowest obtained from t0. these findings were partially correlated with the observation of siavoshi et al. (2011). grains spike-1 grains spike-1is significantly influenced by soil amendments. during the research period, a significantly higher number of grains spike-1 was recorded from the treated plot in comparison with the control plot. the rank of treatments were t8>t4> t5> t7> t3> t6> t2> t1> t0 (table 2). the maximum number of grains spike-1 (45.73) was recorded from t8 which was statistically similar to t4 (44.80) and the least value from t0 (33.67). considering the organic soil amendment treatments, poultry manure (t4) performed the better response; such result might be due greater amount of n within it, which produced more dry matter and partitioning it towards grains which enhanced the grains spike-1. this result was confirmatory with the outcomes of shah et al. (2010) and mukhtiar et al. (2018). table 1. effect of organic and probiotic soil amendments on yield and yield contributing characters of wheat treatments spike length (cm) spikeletsspike-1 (no.) fertile spikeletsspike-1 (no.) 20162017 20172018 20182019 20162017 20172018 20182019 20162017 20172018 20182019 t0 7.31e ± 0.16 7.12f ± 0.10 7.00e ± 0.05 14.66d ± 0.21 14.20d ± 0.20 13.80d ± 0.15 14.00g ± 0.20 13.78f ± 0.17 13.22f ± 0.19 t1 7.45de ± 0.11 7.55e ± 0.11 7.63d ± 0.08 15.33c ± 0.14 15.50c ± 0.26 15.77c ± 0.17 14.74f ± 0.22 14.86e ± 0.13 15.08e ± 0.22 t2 7.62cde 0.12 7.73de ± 0.11 7.84d ± 0.08 15.60c ± 0.12 15.86c ± 0.20 16.10c ± 0.14 15.20de ± 0.12 15.32d ± 0.10 15.51d ± 0.13 t3 7.77bcd 0.09 7.99bcd ± 0.12 8.18c ± 0.10 16.10b ± 0.14 16.40b ± 0.23 16.63b ± 0.16 15.50cd ± 0.14 15.72c ± 0.12 15.93c ± 0.08 t4 8.12ab ± 0.12 8.29ab ± 0.11 8.43ab ± 0.08 17.16a ± 0.13 17.59a ± 0.17 17.81a ± 0.16 16.60a ± 0.16 16.78a ± 0.09 17.00a ± 0.13 t5 7.91bc ± 0.10 8.12abc ± 0.07 8.25bc ± 0.06 16.43b ± 0.14 16.68b ± 0.16 16.88b ± 0.21 15.90b ± 0.16 16.16b ± 0.15 16.40b ± 0.17 t6 7.54cde ± 0.10 7.66de ± 0.08 7.77d ± 0.08 15.51c ± 0.15 15.78c ± 0.20 16.01c ± 0.17 14.90ef ± 0.18 15.10de ± 0.17 15.41de ± 0.15 t7 7.79bcd ± 0.12 7.95cd ± 0.09 8.08c ± 0.06 16.26b ± 0.19 16.46b ± 0.11 16.70b ± 0.19 15.62bc ± 0.15 15.89bc ± 0.13 16.12bc ± 0.16 t8 8.27a ± 0.08 8.41a ± 0.09 8.60a ± 0.10 17.36a ± 0.17 17.68a ± 0.16 17.97a ± 0.17 16.89a ± 0.13 17.06a ± 0.10 17.24a ± 0.18 ls ** ** ** ** ** ** ** ** ** cv (%) 4.58 4.03 2.93 2.76 3.23 3.23 2.42 2.00 2.61 in the column, mean values bearing similar letter(s) or without letter are similar and those having dissimilar letters are differed significantly as per duncan’s multiple range test. t0 = control, t1= rice straw + vermicompost + green manure, t2 = cow dung + vermicompost + green manure, t3 = compost + vermicompost + green manure, t4 = poultry manure + vermicompost + green manure, t5 = t. harzianum + vermicompost + green manure, t6 = mungbean residues + vermicompost + green manure, t7 = t. viride+ vermicompost + green manure, t8 = chemical fertilizer, ls = level of significance, **= 1% level of significance, cv = coefficient of variation yield and seed quality of wheat through probiotic and organic soil amendment 5 grains weight spike-1 as a yield component, grains weight spike-1 of wheat is an important factor that contributes to the grain yield (peltonen-sainio et al., 2007). grain weight spike-1 at harvest varied significantly due to different soil amendment treatments (table 2). among the different soil amendment treatments, t4 (2.14 g) performed better than other treatments. the rest of the treatments were also showed as descending by t5 (2.06 g), t7 (2.01 g), t3 (1.99 g), t2 (1.93 g), t6 (1.89 g), t1 (1.86 g), while the lowest one in t0 (1.60 g). the advancement of grain weight spike-1 that provided with poultry manure treatment combination might be due to balanced nutrient stock during the grain filling stage and improvement of soil fertility. a similar result was also reported by garg and bahla (2008). 1000-grain weight for cereal crops, 1000-grain weight is an important factor to determine the yield and yield attributes (metho et al., 1998). the data of 1000-grain weight of wheat indicated that chemical fertilizer (t8) and poultry manure combination (t4) significantly increased the weight (54.12 g and 53.90 g) while plants that did not receive any soil amendments (t0) showed the lowest (48.78 g) might be due to availability of nutrients throughout the growing period and improvement of soil characters. this outcome was agreed with ahmed et al. (2017). table 2. effect of organic and probiotic soil amendments on yield and yield contributing characters of wheat treatments grains spike-1(no.) grain weight spike-1(g) 1000-grainweight (g) 20162017 20172018 20182019 20162017 20172018 20182019 20162017 20172018 20182019 t0 36.88f ± 0.30 35.04e ± 0.30 33.67i ± 0.87 1.66g ± 0.03 1.62g ± 0.02 1.60g ±0.04 49.52f ± 0.44 48.61e ± 0.51 48.78i ± 0.41 t1 36.98f ± 0.22 38.42d ± 0.23 39.53h ± 0.88 1.74f ± 0.02 1.80f ± 0.03 1.86f ± 0.04 50.03f ± 0.37 51.05d ± 0.30 51.30h ± 0.31 t2 38.11e ± 0.21 39.36d ± 0.26 40.67f ± 0.96 1.80ef ± 0.03 1.88de ± 0.03 1.93e ± 0.05 51.19de ± 0.33 51.84bcd ± 0.59 51.95f ± 0.33 t3 38.76d ± 0.21 40.51c ± 0.39 41.58e ± 1.02 1.83de ± 0.02 1.91d ± 0.03 1.99d ± 0.04 51.77cd ± 0.19 52.34a-d ±0.34 52.49e ± 0.34 t4 42.11b ± 0.40 43.50a ± 0.59 44.80b ± 1.13 1.98b ± 0.02 2.10b ± 0.02 2.14b ± 0.05 52.94ab ± 0.27 53.51ab ± 0.47 53.90b ± 0.39 t5 40.17c ± 0.22 41.59b ± 0.43 43.14c ± 1.08 1.93bc ± 0.03 2.02c ± 0.02 2.06c ± 0.05 52.27bc ± 0.21 52.98abc ± 0.90 53.19c ± 0.38 t6 37.20f ± 0.20 38.71d ± 0.27 40.23g ± 0.97 1.77ef ± 0.03 1.84ef ± 0.03 1.89f ± 0.05 50.48ef ± 0.40 51.39cd ± 0.31 51.60g ± 0.34 t7 39.73c ± 0.25 40.83bc ± 0.42 42.50d ± 1.07 1.89cd ± 0.02 1.99c ± 0.02 2.01d ± 0.05 51.97bcd ± 0.14 52.51a-d ± 0.26 52.64d ± 0.36 t8 42.74a ± 0.37 44.41a ± 0.53 45.73a ± 1.04 2.07a ± 0.03 2.15a ± 0.03 2.20a ± 0.05 53.28a ± 0.30 53.81a ± 0.29 54.12a ± 0.40 ls ** ** ** ** ** ** ** ** ** cv (%) 1.52 2.55 1.09 3.69 2.90 1.48 1.90 3.12 1.23 in the column, mean values bearing similar letter(s) or without letter are similar and those having dissimilar letters are differed significantly as per duncan’s multiple range test. t0 = control, t1= rice straw + vermicompost + green manure, t2 = cow dung + vermicompost + green manure, t3 = compost + vermicompost + green manure, t4 = poultry manure + vermicompost + green manure, t5 = t. harzianum + vermicompost + green manure, t6 = mungbean residues + vermicompost + green manure, t7 = t. viride+ vermicompost + green manure, t8 = chemical fertilizer, ls = level of significance, **= 1% level of significance, cv = coefficient of variation 6 hossain et al. grain yield different yield component specifically spikesm-2 , number and weight of grains spike-1 and 1000grain weight mathematically functioned on yield of cereal crop (thiry et al., 2002). application of different soil amendments showed significant variation of grain yield of wheat (figure 1, 2 and 3). in the last year, influences of different treatments on grain yield were found to be ranked in that following descending order t8 (4.25 t ha-1) > t4 (4.09 t ha-1) > t5 (3.85 t ha-1) > t7 (3.64 t ha-1) > t3 (3.60 t ha-1) > t2 (3.34 t ha-1) > t6 (3.27 t ha-1) > t1 (3.05 t ha-1) > t0 (2.36 t ha-1). better performance of t4 might be enhanced soil fertility and improvement of physical conditions, reduction of nutrient losses which collectively contributed to the higher grain yield. this result was in confirmed to that with the observation of zhang et al. (2016). straw yield soil amendments significantly influenced the straw yield (figure 1, 2 and 3). among the different treatments, t8 (5.40 t ha-1) performed superior. the rest of the treatments were also showed significant result ranked as descending by t4 (5.31 t ha-1), t5 (5.14 t ha-1), t7 (5.05 t ha-1), t3 (4.93 t ha-1), t6 (4.83 t ha-1), t2 (4.73 t ha-1) and t1 (4.60 t ha-1), while the lowest one in t0 (4.18 t ha-1). this performance of organic manures might be due to the capability of abundant nutrients supply and the creation of a favorable growth environment. a similar result was also noted by auti et al. (1999) and kumar and abraham (2018). fig. 1. effect of organic and probiotic soil amendments on grain yield and straw yield of wheat in 2016-2017. fig. 2. effect of organic and probiotic soil amendments on grain yield and straw yield of wheat in 2017-2018. 0 1 2 3 4 5 6 t0 t1 t2 t3 t4 t5 t6 t7 t8 y ie ld ( t h a -1 ) grain yield straw yield 0 1 2 3 4 5 6 t0 t1 t2 t3 t4 t5 t6 t7 t8 y ie ld ( t h a -1 ) grain yield straw yield yield and seed quality of wheat through probiotic and organic soil amendment 7 fig. 3. effect of organic and probiotic soil amendments on grain yield and straw yield of wheat in 2018-2019. harvest index treatment t8 showed a maximum harvest index (44.05%) followed by t4 (43.48%) and the lowest one (36.13%) derived from t0 during 2018-2019 (figure 4).the boosting harvest index might be the continued supply of nutrients and higher dry matter distribution towards grain formation provided by the poultry manure treatment combination. this result was in agreement with the investigation of kabesh et al. (2009) and khan et al. (2018). fig. 4. effect of organic and probiotic soil amendments on harvest index of wheat in 20162017, 2017-2018 and 2018-2019. 0 1 2 3 4 5 6 t0 t1 t2 t3 t4 t5 t6 t7 t8 y ie ld ( t h a -1 ) grain yield straw yield 0 5 10 15 20 25 30 35 40 45 2016-2017 2017-2018 2018-2019 h a rv e st i n d e x t0 t1 t2 t3 t4 t5 t6 t7 t8 8 hossain et al. effect of soil amendments on seed quality after every harvesting, seeds were collected separately from each treatment and preserved. major seed quality characters viz. germination, vigor index and total soluble protein content were determined. the introduction of designed soil amendments not only developed the growth and yield of wheat but also enriched parameters of seed quality. germination (%) soil amendments influenced the germination of seed. the treatment t4 significantly enhanced (92.08%) the germination followed by t5 (88.89%) and t0 had a lower effect (74.78%) on germination in 2018-2019 (table 3). a similar trend was also observed in the previous two cropping season. this might be due to an adequate supply of nutrients which helps to build up carbohydrate-like seed elements thus producing vigorous seeds. the outcome of the investigation was the conformity of previous results of gowda et al. (2010) and aslam et al. (2011). table 3. effect of organic and probiotic soil amendments on seed quality of wheat treatments germination (%) vigor index soluble protein content(mg g-1 fw) 20162017 20172018 20182019 20162017 20172018 20182019 20162017 20172018 20182019 t0 70.50h ± 0.92 72.53g ± 0.93 74.78g ± 0.85 24.70h ± 0.42 27.49f ± 0.40 28.84f ± 0.27 77.31e ± 0.28 77.47e ± 0.58 79.10e ± 0.42 t1 75.31g ± 1.08 77.54f ± 1.02 79.67f ± 1.18 28.20g ± 0.55 32.52e ± 0.54 34.39e ± 0.36 78.20e ± 0.45 79.68d ± 1.05 79.58e ± 0.52 t2 78.14f ± 0.82 80.88de ± 0.98 83.67d ± 0.96 31.69e ± 0.85 34.42d ± 0.96 35.93d ± 0.38 80.25d ± 0.46 80.97cd ± 0.73 82.98d ± 0.39 t3 81.08d ± 0.85 83.86bc ± 0.92 86.17c ± 0.94 32.60d ± 0.43 36.84b ± 0.49 38.36b ± 0.34 80.20d ± 1.02 81.98c ± 1.44 82.24d ± 1.28 t4 88.27a ± 1.05 89.93a ± 1.01 92.08a ± 1.24 35.99a ± 0.73 39.48a ± 0.84 41.54a ± 0.58 88.17b ± 1.89 93.30a ± 0.90 92.56b ± 0.70 t5 84.75b ± 1.06 86.52b ± 1.15 88.89b ± 0.84 34.57b ± 0.52 37.30b ± 0.58 39.26b ± 0.46 87.59b ± 0.59 88.30b ± 0.66 91.03c ± 0.99 t6 78.76e ± 0.89 78.40ef ± 1.46 81.83e ± 1.42 30.21f ± 0.46 34.68d ± 0.33 35.37de ± 0.33 81.51c ± 0.72 81.31c ± 0.63 82.62d ± 0.70 t7 83.59c ± 0.93 83.33cd ± 1.05 86.28c ± 0.96 33.56c ± 0.43 35.78c ± 0.38 36.98c ± 0.42 87.88b ± 0.58 89.17b ± 0.83 91.99bc ± 0.67 t8 81.37d ± 0.86 84.57bc ± 1.05 86.76c ± 01.16 32.46d ± 0.50 34.03d ± 0.34 37.27c ± 0.48 93.32a ± 1.08 93.80a ± 1.20 96.43a ± 1.14 ls ** ** ** ** ** ** ** ** ** cv (%) 0.82 3.34 1.79 0.97 3.16 2.91 1.58 1.61 1.42 in the column, mean values bearing similar letter(s) or without letter are similar and those having dissimilar letters are differed significantly as per duncan’s multiple range test. t0 = control, t1= rice straw + vermicompost + green manure, t2 = cow dung + vermicompost + green manure, t3 = compost + vermicompost + green manure, t4 = poultry manure + vermicompost + green manure, t5 = t. harzianum + vermicompost + green manure, t6 = mungbean residues + vermicompost + green manure, t7 = t. viride+ vermicompost + green manure, t8 = chemical fertilizer, ls = level of significance, **= 1% level of significance, cv = coefficient of variation yield and seed quality of wheat through probiotic and organic soil amendment 9 vigor index the vigor index is an imperative quality of seed that indicates the potentiality of constant emergence of seedlings (pradeep, 2018). after three years of experimentation, considering the comparable trend of vigor index from respective treatments, poultry manure (41.54) and trichoderma harzianum (39.26) in comparison with control treatment (28.84).the speed of germination i.e. vigor index might be significantly different for providing the substantial macro and micro nutrient in the grain filling stage and carbohydrate stored in seed enhances the quality. this result was in agreement with the reflection of farhad et al. (2011). total soluble protein content among the major cereals, wheat is the prominent source of vegetal protein (13%). the results in general t8 produced higher protein (96.43 mg g-1 fw) followed by t4 (92.56 mg g-1 fw) and the least at t0 (79.10 mg g-1 fw). the increase of protein content might be due to the availability of high npk that satisfy the plant requirement and accumulated n in leaf mobilized to seed components which leads the protein production. this result was in corroborates with the findings of abedi et al. (2010) and rasul et al. (2015). considering the fact, the poultry manure combination treatment (t4) was an environmentally friendly alternative to chemical fertilizer (t8) for increasing soil fertility and crop productivity. conclusion there is a potentiality for sustainable improvement of wheat growth, yield and seed quality with organic soil amendment through probiotic and organic manure. in that term, the inclusion of green manure, vermicompost and poultry manure might be a worthy alternative. organic manures particularly poultry manure was a healthier source for improvement of growth, yield parameters and seed quality of wheat as compared to other manures. so, the poultry manures could be suggested for soil amendment and increase wheat production in the studied region. references abedi, t., a. alemzadeh and s.a. kazemeini. 2010. effect of organic and inorganic fertilizers on grain yield and protein banding pattern of wheat. aust. j. crop sci. 4:384-389. ahmed, b.e.a.m., a.a. ishag, m.k. hassan and m.o. ahmed. 2017. response of two wheat cultivars (triticum aestivum l.) to amended nitrogen fertilizer on yield and grain quality in halfa elgadidah area. moj. biol. med. 1(5): 133-136. ahmed, s.i., m.k. abbasi and g. rasool. 2002. integrated plant nutrition system (ipns) in wheat under rain fed conditions of rawalakot azad jammu and kashmir [pakistan]. pak. j. soil sci. 21(1&2): 79-86. alam, m.m., m.r. karim and j.k. ladha. 2013. integrating best management practices for rice with farmers’ crop management techniques: a potential option for minimizing rice yield gap. field crops res. 144: 62-68. aslam, m., m.a. khan, i.u. awan, e.a. khan, a.a. khan and g. jilani. 2011. effect of single and combined use of various organic amendments on wheat grown over green manured soil: growth and yield attributes. pak. j. nutr. 7: 640-646. auti, a.k., s.c. wadile and v.s. pawar. 1999. yield, quality and nutrient removal of wheat (triticum aestivum l.) as influenced by levels and sources of fertilizer. indian j. agron.44: 119-120. bari (bangladesh agricultural research institute). 2014. krishi projukti hatboi (handbook on agrotechnology), 6th edition, gazipur, bangladesh. 10 hossain et al. bari (bangladesh agricultural research institute).2011. krishi projukti hatboi (handbook on agrotechnology), 5th edition, gazipur, bangladesh. bbs (bangladesh bureau of statistics). 2008. statistical yearbook of bangladesh. statistics and informatics div., ministry of planning. govt. people's repub., bangladesh, dhaka. bbs (bangladesh bureau of statistics).2017.statistical yearbook of bangladesh. statistics and informatics div., ministry of planning. govt. people's repub., bangladesh, dhaka. farhad. w, m.f. saleem, m.a. cheema, h.z. khan and h.m. hammad. 2011. influence of poultry manure on the yield and quality of spring maize. crop environ. 2: 6-10. garg, s. and g.s. bahla. 2008. phosphorus availability to maize as influenced by organic manures and fertilizer p associated phosphatase activity in soils. bioresour. technol. 99: 5773-5777. gomez. k.a. and a.a. gomez.1984. statistical procedures for agricultural research (2nd edition). international rice research institute. john wiley and sons, a wiley-inter science publication. gowda, c., p.n.k. biradar, b.n. patil, j.s. awakknavar and r. hunje. 2010. effect of organic manures on growth, seed yield and seed quality of wheat. karnataka j. agric. sci. 21: 366368. guy, c., d. haskell, l. neven, p. klein and c. smelser. 1992. hydration-state-responsive proteins link cold and drought stress in spinach. planta. 188: 265-270. hajieghrari, b. and m. mohammadi. 2016. growth-promoting activity of indigenous trichoderma isolates on wheat seed germination, seedling growth and yield. aust. j. crop sci.10: 13391347. hue, n.v. and j.a. silva. 2000. organic soil amendments for sustainable agriculture: organic sources of nitrogen, phosphorus and potassium: plant nutrient management in hawaii’s soils, approaches for tropical and subtropical agriculture. college of tropical agriculture and human resources, university of hawaii, manoa. 133-144. ista (international seed testing association). 1985. international rules for seed testing. seed sci. technol. 13: 299-513. kabesh, m.o., m.f. el-kramany, g.a. sary, h.m. el-naggar and s.h. gehan. 2009. effects of sowing methods and some bio-organic fertilization treatments on yield and yield components of wheat. res. j. agric. biol. sci. 5: 97-102. khan, t.u., m.t. jan, a. khan, g. ahmad, m. ishaq, k. afridi, a. murad, m.a. qureshi, i. ahmad and m. seed. 2018. integrated management of fertilizer nitrogen and poultry manure enhances wheat production. pak. j. agric. res. 31: 207-215. kumar, s. and t. abraham. 2018. productivity potential of wheat under certified organic production system. int. j. curr. microbiol. appl. sci. 7: 281-288. maguire, j.d. 1962. speed of germination-aid in selection and evaluation for seedling emergence and vigor. crop sci. 2: 176-177. metho, l.a., p.s. hammes and e.a. beyers. 1998. the effect of soil fertility on the contribution of main stem, tillers and kernel position to grain yield and grain protein content of wheat. s. afr. j. plant soil 15: 53-60. mukhtiar, a., a. waqar, m.k. khalil, m. tariq, s. muhammad, a. hussain and a. kamal. 2018. evaluating the potential organic manure for improving wheat yield and quality under agroclimatic conditions of pakistan. adv. crop sci. tech. 6: 1-4. nguyen, m.l., r.j. haynes and k.m. goh. 1995. nutrient budgets and status in three pairs of conventional and alternative and mixed cropping farms in canterbury, new zealand. agric. ecosyst. environ. 52: 149-162. yield and seed quality of wheat through probiotic and organic soil amendment 11 peltonen-sainio, p., a. kangas, y. salo and l. jauhiainen. 2007. grain numbers dominate grain weight in temperate cereal yield determination: evidence based on 30 years of multi-location trials. field crops res. 100: 179-188. pradeep, p. 2018. seed quality parameters (germination percentage and seedling vigor index) of rabi sorghum seeds influenced by rice weevil infestation. moj. toxicol. 4: 391–396. pradhan, s.b. 1992. status of fertilizer use in developing countries of asia and the pacific region in: proc. reg. fadinap sem. chiang mai, thailand: 37-47. rasul, g.a.m., s.t. ahmed and m.q. ahmed. 2015. influence of different organic fertilizers on growth and yield of wheat. american-eurasian j. agric. environ. sci. 15: 1123-1126. sabaghina, n., m. janmohammadi and a.e. segherloo. 2014. evaluation of some agromorphological traits diversity in iranian bread wheat genotypes. annales umcs, biologia 69: 79-92. shah, s.a., s.m. shah, w. mohammad, m. shafi, h. nawaz, s. shehzadi and m. amir. 2010. effect of integrated use of organic and inorganic nitrogen sources on wheat yield. sarhad j. agric. 26: 559-563. shewry, p.r., n.g. halford, p.s. belton and a.s. tatham. 2002. the structure and properties of gluten: an elastic protein from wheat grain. philosophical transactions of the royal society of london series b: biol. sci. 357: 133-142. siavoshi, m.,a. nasiri and s.l. laware. 2011. effect of organic fertilizer on growth and yield components in rice (oryza sativa l.). j. agric. sci. 3:217.224. singh, a., m.s. darhvankar and g. singh. 2018. impact of organic and inorganic amendments on yield and growth of wheat (triticum aestivum l.). int. j. curr. microbiol. appl. sci. 7: 789794. thiry, d.e., r.g. sears, j.p. shroyer and g.m. paulsen. 2002. relationship between tillering and grain yield of kansas wheat varieties. kansas state university agricultural experimental station and cooperative extension service: 1-5. yadvinder-singh, s. bijay, r.k. gupta, j. ladha, j.s. bains and j. singh. 2008. evaluation of press mud cake as a source of nitrogen and phosphorus for the rice-wheat cropping system in the indo-gangetic plains of india. biol. fertil. soils. 45: 289-296. zeidan, m.s. and m.f.e. kramany. 2001. effect of organic manure and slow-release n fertilizer on the productivity of wheat (triticum aestivum l.) in sandy soil. acta agronomica hungarica. 49: 379-385. zhang, h.q., x.y. yu, b.n. zhai, z.y. jin and z.h. wang. 2016. effect of manure under different nitrogen application rates on winter wheat production and soil fertility in dry land. iop conf. ser.: earth environ. sci. 39(1):1-10. https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1692935 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1692935 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1692935 bangladesh agron. j. 2023, 26(1): 40-47 selection of mungbean genotypes against waterlogging stress m.a. jahan1* and f. ahmed2 1department of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2plant physiology division, bari, gazipur-1701, bangladesh *corresponding author, email: jahansau@yahoo.com (received: 29 may 2023, accepted: 18 september 2023) keywords: mungbean, genotypes and waterlogging abstract a pot experiment was conducted in the vinyl house of sher-e-bangla agricultural university (sau), dhaka-1207, during kharif-i season (march to june 2022) to identify waterlog tolerant mungbean genotypes. thirty mungbean genotypes (29 advanced lines and one variety, bari mung-6) were evaluated under waterlogging (96 hours) and normal conditions. waterlogging caused a drastic reduction in dry matter and seed yield in mungbean, however, genotypes showed variable response to waterlogging. under waterlog condition the higher relative yield was found in m11, m8, m30, m7, m16 and m14 while lower in m2 and m17. dry matter production also varied among the genotypes due to waterlogging; however, dry matter production of the genotypes m8, m7, m22, m2, m19 and m11 were comparatively higher than other genotypes. stress tolerance index (sti), yield index (yi) and relative yield (ry) of m16, m20, m7, m8, m11, m30 and m14 were higher than other genotypes. on the basis of dry matter production, sti, yi and ry, genotypes m7, m8, m11, m12, m16, and m20 could be selected as relatively tolerant genotypes against waterlogging stress. introduction mungbean (vigna radiata (l.) wilczak) is one of the important pulse crops in bangladesh. it is a short-duration crop in various cropping systems, increases tenant farmers' income and improves soil fertility (tomooka et al., 1991). its seeds contain about ~24% easily digestible protein, a significant amount of fiber, antioxidants and minerals. seeds can be consumed as whole or split, as sprout or ground into flour for soup. various biotic and abiotic factors are responsible for low yield of mungbean. abiotic stresses are a major environmental problem in agricultural crop production (lesk et al., 2016). among the abiotic stresses, excess moisture or waterlogging stands prominent. mungbean cannot withstand waterlogging, particularly during the early stages of growth (singh and singh 2011). waterlogging of soil is a major limiting factor for crop growth in humid regions (drew, 1991). prolonged rainy period or heavy rainfall in the field with poor soil drainage significantly reduces the seed yield of grain legumes. the growth and seed yield of mungbean are adversely affected by waterlogging of the soil (yadav and saxena, 1998), but the yield response to waterlogging has not been studied as intensively as in some other leguminous crops, such as cowpea (minchin and summerfield, 1976) and soybean (scott et al., 1990). mungbean is grown in kharif-i (the major growing season from last week of february to middle of march) and kharif-ii (mid-august to last week of september) seasons in bangladesh. mungbean usually suffers from unexpected heavy rainfall at sowing or emergence time that cause total crop failure. pre-sowing heavy rain causes delay in sowing resulting in poor seed yield. delayed sown crops face excess rainfall at the time of reproductive phase which is the root cause of enormous losses of seed yield and quality. reduction of growth and yield caused by waterlogging varies with the crop species and genotype (wondimagegne et al., 1992). varietal difference of mungbean to waterlogging stress was reported selection of mungbean genotypes against waterlogging stress 41 by bagga et al. (1984) and the effect on growth and physiological process, duration of flooding and stage at which the plant encountered the stress was studied by islam (2003). despite this fact, very little information is available on the responses of mungbean to soil waterlogging in bangladesh. waterlogging reduces plant growth by affecting one or several physiological processes. several studies revealed that genotypes differed in their responses to water stress conditions. genotypic differences of mungbean to waterlogging stress was reported by bagga et al. (1984) and the effect on growth and physiological process, duration of flooding and stage at which the plant encountered the stress was studied by islam (2003). however, the yield response of waterlogging in mungbean has not been studied as intensively done in some other legumes like soybean and cowpea (khadeja et al., 2022 and omolayo et al., 2022). therefore, the present investigation was carried out to study the effect of waterlogging on mungbean genotypes and to find out the waterlogging tolerant genotypes. materials and methods a pot experiment was conducted at the vinyl house of sher-e-bangla agricultural university campus during kharif-i season of 2022. thirty mungbean genotypes (29 advanced lines and bari mung-6) were used as test genotypes (table 1) under normal and waterlogging conditions. table 1. thirty mungbean genotypes used in the study m1= v1000319ag m11=v1001854bg m21=v1004044bg m2= v1000542by m12=v1002063bg m22=v1004069bg m3=v1000559ag m13=v1002195ag m23=v1004307ag m4=v1000723ag m14=v1002206ag m24=v1004789bg m5=v1000749ag m15=v1002432ag m25=v1004933ag m6=v1000764ag m16=v1002537ag m26=v1004937ag m7=v1001282ag m17=v1002926ag m27=v1004954bg m8=v1001406bg m18=v1003755bg m28=v1004968ag m9=v1001692ag m19=v1003925blm m29=v1004973blm m10-v1001698bg m20=v1004024ag m30=bari mung-6 the experiment was laid out in randomized complete block design (factorial) with 3 replications. plastic pots (with small 4 holes in bottom of each pot; top diameter: 20 cm, bottom diameter: 15 cm and height 19 cm; capacity 10 kg soil) were filled up with well mixed soil and cowdung (4:1). ten seeds were sown in each pot on 7th march 2022. fertilizers were applied @ 24-32-48-24-3-1.5 kg ha−1 npksznb. all fertilizers were applied as basal at sowing. irrigation was done as and when required for maintaining adequate soil moisture before imposing the treatment. after emergence plants were thinned to three plants in each pot. at 30 days after sowing, waterlogging was imposed by transferring each pot into a larger (top diameter: 35 cm, bottom diameter: 30 cm and height 40 cm; capacity 30 l) plastic bucket (walelign and berhanu, 2015; and selina et al., 2002). waterlogging treatments were given by filling the outer container with water up to 3-5 cm above the soil surface of the pot. after four consecutive days (96 hours) of waterlogging pots were removed from waterlogging and kept those at normal condition up to maturity to observe plant growth and seed yield. stress tolerance index (sti) was calculated according to fernandez (1992): sti = ys ×yp (yp)2 yield index (yi) was calculated as follows: yi = (ys)/ (y̅ s) 42 jahan & ahmed where, ys and yp are the yield of individual genotypes under stress and non-stress conditions, respectively; y ̅s and y ̅p are the average yield of all genotypes under stress and non-stress conditions, respectively. the relative yield (ry) under waterlog condition was calculated as the yield of a specific genotype under waterlog divided by the highest yielding genotype in the population. at harvest yield and yield components data were collected from three pots and analyzed statistically using cropstat v. 7.2 software and mean separation was done by lsd test at 5% level of significance. results and discussion effect of waterlogging yield and yield components of mungbean genotypes were significantly reduced by waterlogging (table 2). under normal condition plant height was 37.03 cm, which was reduced (32%) to 25.22 due to waterlogging. kyu et al. (2021) and amin et al. (2017) also reported reduced plant height (29-31%) in mungbean under waterlogging. number of pod plants–1 was reduced by about 55% due to waterlogging. islam (1994) reported that waterlogging significantly reduced pods plant–1 in mungbean and 36% more pods were produced in control plants than waterlogged plants. pod length was also reduced due to waterlogging from 7.68 cm to 6.62 cm. waterlogging caused reduction in number of seeds pods–1; under normal condition it was 10 seeds pods–1, which was reduced to 7.89 seeds pod–1. seed size was reduced due to waterlogging, 100seed weight under normal condition was 4.58 g while under waterlogging it was 4.22 g. seed yield plant–1 was drastically reduced (57%) by waterlogging and it was 7.64 g plant−1 under normal condition while that was only 3.34 g plant–1 under waterlogging. amin et al. (2017) reported 10 to 70% yield reduction in mungbean under waterlogging of various genotypes. umaharan et al. (1997) reported that waterlogging during the vegetative period resulted in a significant decline in pod yield of cowpea and the reductions reflected in the number of pod plant–1. wang et al. (2013) reported that yield loss due to waterlogging may vary between 15% and 80% depended on the crop species and growth stage, soil type and duration of the stress. table 2. effect of waterlogging on yield and yield component on genotypes treatment plant height (cm) no of pods plant−1 pod length (cm) seeds pod−1 100-seed weight (g) grain yield (g plant–1) normal 37.93 22.19 7.68 10.20 4.58 7.69 waterlogging 26.12 9.61 6.62 8.09 4.22 3.34 lsd(0.05) 1.50 0.53 0.37 0.33 0.20 0.23 cv (%) 6.10 11.70 8.40 7.82 6.80 5.40 effect of genotypes yield and yield components of the mungbean genotypes showed significant variability (table 3). highest plant height was observed in m24 (41.55 cm), which was identical with m2, m8, m12, m18, m26, m28 and m30 but significantly higher than other genotypes. moderate type of plant height was observed in m2 (36.4 cm) which was statistically similar with m3, m5, m13, m17, m19, m20 and m21. rest of the genotypes were short stature and shortest plant was found in m23 (27.75 cm). number of pods plant–1 of the genotypes varied significantly. the highest pods plant−1 (27.35) was observed in m20, which was significantly higher than all other genotypes. the lowest number of pods plant (7.6) was found in m15, which was identical with m12, m11 and m30. significant variation was found in pod length of the genotypes. the highest pod length (11.30 cm) was recorded in m12, which was significantly higher than other genotypes. the lowest pod length (6.14 cm) was observed in m19, which was identical with rest of the genotypes. the selection of mungbean genotypes against waterlogging stress 43 highest number of seeds pod−1 was found in m12 (11.30), which was identical with m26, m28, m22, m25, m5 and m2. the lowest number of seeds pod−1was found in m15 (6.35), which was identical with m8. the bold seeded genotypes were m30, m15, m13 and m11 and their 100seed weight were 6.89, 6.65g, 6.52g and 6.38g, respectively. table 3. effect of genotypes on yield and yield components of mungbean treatment plant height (cm) no of pods plant−1 pod length (cm) seeds pod−1 100-seed weight (g) seed yield (g plant−1) m1 30.40 14.90 7.11 9.15 3.95 5.11 m2 36.40 15.95 7.31 10.15 3.09 4.94 m3 32.30 20.10 6.28 8.50 3.56 5.29 m4 25.50 16.45 6.91 8.10 3.84 4.59 m5 34.60 17.10 7.08 10.20 3.90 5.31 m6 26.25 17.60 6.96 9.15 3.95 5.12 m7 31.40 22.95 6.52 9.75 3.38 6.07 m8 39.10 21.35 6.78 7.05 3.25 5.42 m9 26.15 14.45 6.89 9.25 3.37 4.13 m10 30.50 19.85 6.20 9.45 3.40 5.24 m11 29.55 8.75 8.21 9.15 6.38 4.17 m12 39.50 8.35 11.30 11.30 5.99 6.10 m13 34.25 10.10 8.10 7.85 6.52 5.26 m14 27.65 10.95 7.46 8.30 5.62 4.33 m15 29.25 7.60 6.30 6.35 6.65 3.81 m16 24.70 22.00 6.99 8.25 4.92 8.11 m17 32.15 16.20 6.51 8.80 3.82 7.13 m18 37.50 20.25 6.66 9.20 3.92 6.94 m19 32.35 16.25 6.14 8.50 3.46 3.88 m20 31.88 27.35 7.50 9.55 4.66 10.48 m21 34.85 18.70 6.68 9.30 4.56 5.71 m22 31.40 22.20 7.14 10.40 4.73 9.15 m23 27.75 13.45 6.68 9.90 4.09 4.63 m24 41.55 18.60 6.65 8.40 4.28 5.92 m25 30.80 15.35 7.25 10.20 3.84 5.56 m26 37.15 13.60 7.08 10.60 3.98 4.83 m27 31.05 9.95 7.48 9.40 4.81 3.94 m28 37.75 13.45 7.34 10.40 4.00 5.38 m29 28.80 14.40 7.04 9.20 3.25 4.03 m30 38.25 15.50 9.07 8.60 3.89 4.99 lsd (0.05) 5.83 2.04 1.42 1.27 0.79 0.88 cv (%) 6.10 11.70 8.40 7.82 6.80 5.40 the lowest 100-seed weight (3.09g) was observed in m2, which was identical with m8, m29, m9, m7, m10, m19, m3, m17, m4 and m25. seed yield of the genotypes varied significantly among the genotypes studied. varietal/genotypic difference of mungbean to waterlogging effect was reported by bagga et al. (1984). interaction effect genotype and waterlogging interaction showed significant variation on seed yield and yield components (table 4). 44 jahan & ahmed table 4. interaction effect of genotypes and waterlogging on yield and yield components of mungbean treatments plant height (cm) no of pods plant–1 pod length (cm) seeds/pod 100-seed weight (g) seed yield (g plant–1) m1 n 36.2 20.9 7.21 9.4 4.02 7.15 w 24.6 8.9 7.00 8.9 3.87 3.07 m2 n 43.6 25.3 7.82 11.3 3.25 7.81 w 29.2 6.6 6.80 9.0 2.92 2.06 m3 n 39.7 27.3 6.71 9.9 3.57 7.07 w 24.9 12.9 5.84 7.1 3.54 3.52 m4 n 32.4 22.3 7.21 8.5 3.86 5.97 w 18.6 10.6 6.60 7.7 3.82 3.21 m5 n 40.6 23.3 7.33 10.3 3.96 6.91 w 28.6 10.9 6.83 10.1 3.83 3.72 m6 n 33.1 24.6 7.58 10.0 4.19 7.26 w 19.4 10.6 6.33 8.3 3.71 2.99 m7 n 37.4 28.3 6.76 11.3 3.50 7.22 w 25.4 17.6 6.28 8.2 3.25 4.92 m8 n 43.6 25.6 7.28 8.9 3.44 5.75 w 34.6 17.1 6.27 5.2 3.06 5.08 m9 n 32.6 19.3 7.48 9.5 3.53 5.54 w 19.7 9.6 6.30 9.0 3.21 2.72 m10 n 38.4 27.1 6.49 10.4 3.67 6.97 w 22.6 12.6 5.90 8.5 3.12 3.52 m11 n 31.7 8.9 8.31 10.4 6.39 4.19 w 27.4 8.6 8.11 7.9 6.37 4.14 m12 n 40.9 11.1 12.87 13.8 6.44 7.88 w 38.1 5.6 9.72 8.8 5.54 4.32 m13 n 40.6 12.6 9.03 9.5 6.64 7.20 w 27.9 7.6 7.17 6.2 6.40 3.33 m14 n 30.7 13.3 8.39 9.8 5.83 5.49 w 24.6 8.6 6.53 6.8 5.40 3.18 m15 n 32.6 9.6 7.14 7.5 6.77 5.13 w 25.9 5.6 5.45 5.2 6.53 2.49 m16 n 30.2 29.1 7.35 8.8 5.33 10.26 w 19.2 14.9 6.63 7.7 4.50 5.95 m17 n 40.2 25.1 7.02 9.5 3.83 11.93 w 24.1 7.3 5.99 8.1 3.80 2.32 m18 n 50.6 30.6 7.17 10.5 4.14 10.62 w 24.4 9.9 6.15 7.9 3.70 3.26 m19 n 34.1 21.9 6.61 10.1 3.61 5.41 w 30.6 10.6 5.66 6.9 3.30 2.34 m20 n 36.65 42.1 7.79 10.0 4.71 16.16 w 27.1 12.6 7.21 9.1 4.61 4.80 m21 n 38.5 28.3 7.06 10.1 5.04 8.11 w 31.2 9.1 6.29 8.5 4.07 3.30 m22 n 36.2 34.1 8.02 11.7 5.02 14.34 w 26.6 10.3 6.26 9.1 4.43 3.96 m23 n 29.4 20.3 7.06 10.7 4.30 6.88 w 26.1 6.6 6.30 9.1 3.88 2.38 m24 n 47.4 27.6 7.33 9.9 4.45 8.61 w 35.7 9.6 5.97 6.9 4.10 3.22 m25 n 40.2 24.6 7.76 11.5 3.99 8.82 w 21.4 6.1 6.73 8.9 3.68 2.31 m26 n 45.4 17.9 7.45 11.6 3.83 6.38 w 28.9 9.3 6.71 9.6 4.13 3.29 m27 n 42.2 15.6 8.36 10.7 5.28 6.01 w 19.9 4.3 6.60 8.1 4.33 1.86 m28 n 47.1 18.6 7.64 11.1 4.18 7.96 w 28.4 8.3 7.03 9.7 3.81 2.80 m29 n 33.9 18.9 7.50 10.1 3.61 5.98 w 23.7 9.9 6.57 8.3 2.89 2.09 m30 n 41.6 17.6 8.69 9.3 6.98 5.73 w 24.9 6.1 7.44 7.9 6.80 4.25 lsd (0.05) 8.25 2.89 2.00 1.80 1.11 1.24 cv (%) 6.10 11.70 8.40 7.82 6.80 5.40 n= normal, w= waterlogged selection of mungbean genotypes against waterlogging stress 45 irrespective of genotypes, plant height was reduced due to waterlogging, under normal condition, the maximum plant was observed in m18, which was identical with m24, m28, m26, m8, m2 and m27 and the shortest plant in m1. under waterlogging maximum plant height was found in m2, which was statistically similar with other genotypes under waterlogging except m4, m6, m9, m16 and m27. under waterlogging the minimum plant height was found in m4, which was identical with m6, m9, m16 and m27. pods plant–1 was significantly reduced by waterlogging, genotypes m7, m8 and m16 produced comparatively higher number of pods plant–1 both in normal and waterlogging conditions. nawata et al. (1991) reported that in yard long bean, the yield reduction in plants subjected to long-term waterlogging was due to reduction in pod number per plant. the percentage of reduction over control treatment in pod formation due to continuous 6 days waterlogging ranged from 24.39% to 69.66% depending on the genotypes. pod length also reduced by waterlogging and highest pod length was recorded in m12 both in normal and waterlogging conditions. seeds pod−1 was significantly reduced by waterlogging and among the genotypes higher number of seeds pod−1 was found in m5, followed by m28, m22 and m20 under waterlogging. umaharan et al. (1997) reported that waterlogging during the vegetative period resulted in a significant decline in pod yield of cowpea and the reductions reflected in the number of pod plant-1. seeds pod−1 of m8 and m15 was drastically reduced by waterlogging followed by m14 and m19. seed size also reduced by waterlogging and it varied among the genotypes. highest 100-seed weight was found in m30 both in normal and waterlogging conditions. seed size was drastically reduced in m2 and m29 under waterlogging. seed yield/plant was significantly reduced by waterlogging. under normal condition the better yielding genotypes were m20, m22, m18, m17 and m16. under waterlogging condition better yielding genotypes were m16, m7, m8, m20 and m22. wang et al. (2013) reported that yield loss due to waterlogging may vary between 15% and 80% depended on the crop species and growth stage, soil type and duration of the stress. dry matter production figure 1 shows dry matter production at harvest of the genotypes under normal and waterlogging conditions. dry matter was greatly reduced by waterlogging. under normal conditions the highest dry matter was observed in m10 followed by m8, m20, m18, m22, m24 and the lowest in m14. under waterlogging condition highest dry matter was found in m8 followed by m7, m22, m2, m19, m11 and the lowest in m14. kyu et al. (2021) also reported 60-65% dry matter reduction due to waterlogging in mungbean. fig. 1. total dry matter production at harvest in mungbean genotypes under normal and waterlogging conditions. 46 jahan & ahmed stress tolerance index, yield index and relative yield highest sti was found in m20 (1.52) followed by m22, m16, m7, and m12 and the lowest was found in m27 (table 5). the highest yi was found in m16 followed by m8, m7, m20, and m12 while the lowest yi was found in m27. among the genotypes highest relative yield was found in m16 followed by m8, m7, m20, and m12. table 5. stress tolerance index (sti), yield index (yi) and relative yield (ry) of mungbean genotypes under normal and waterlogging condition genotypes seed yield (g plant−1) index ry normal (yp) waterlogged (ys) sti yi m1 7.15 3.07 0.43 1.10 0.57 m2 7.81 2.06 0.32 0.74 0.38 m3 7.07 3.52 0.49 1.26 0.65 m4 5.97 3.21 0.38 1.15 0.59 m5 6.91 3.72 0.50 1.33 0.69 m6 7.26 2.99 0.43 1.07 0.55 m7 7.22 4.92 0.70 1.76 0.91 m8 5.75 5.08 0.57 1.82 0.94 m9 5.54 2.72 0.29 0.97 0.50 m10 6.97 3.52 0.48 1.26 0.65 m11 4.19 4.14 0.34 1.48 0.77 m12 7.88 4.32 0.67 1.55 0.80 m13 7.20 3.33 0.47 1.19 0.62 m14 5.49 3.18 0.34 1.14 0.59 m15 5.13 2.49 0.25 0.89 0.46 m16 10.26 5.25 1.06 1.88 0.97 m17 11.93 2.32 0.54 0.83 0.43 m18 10.62 3.26 0.68 1.17 0.60 m19 5.41 2.34 0.25 0.84 0.43 m20 16.16 4.80 1.52 1.72 0.89 m21 8.11 3.30 0.53 1.18 0.61 m22 14.34 3.96 1.11 1.42 0.73 m23 6.88 2.38 0.32 0.85 0.44 m24 8.61 3.22 0.54 1.15 0.60 m25 8.82 2.31 0.40 0.82 0.43 m26 6.38 3.29 0.41 1.18 0.61 m27 6.01 1.86 0.22 0.67 0.34 m28 7.96 2.80 0.44 1.00 0.52 m29 5.98 2.09 0.24 0.75 0.39 m30 5.73 4.25 0.48 1.52 0.79 ys= yield of individual genotype under stress, yp = yield of individual genotype under non-stress condition, ry= relative yield. conclusion on the basis of dry matter production, stress tolerance index, yield index and relative yield, mungbean genotypes m7, m8, m11, m12, m16, and m20 could be selected as comparatively tolerant against waterlogging. selection of mungbean genotypes against waterlogging stress 47 references amin, m.r., m.a. karim, q.a. khaliq, m.r. islam and s. aktar. 2017. the influence of waterlogging period on yield and yield components of mungbean (vigna radiata l. wilczek). the agricult. 15(2): 88-100. bagga, a.k., m. bela and o.p.s tomar. 1984. effect of short duration of waterlogging on water use efficiency of two mungbean (vigna radiata l. wilczek) varieties. indian j. physiol. 27: 159-165. drew, m.g. 1991. oxygen deficiency in the root environment and plant mineral nutrition. in: plant life under oxygen deprivation, m.b. jackson, d.d. davies and h. lambers (eds.). academic publishing, the hague. pp. 303-316. fernandez, g.c.j. 1992. effective selection criteria for assessing stress tolerance. in: proceedings of the international symposium on adaptation of vegetables and other food crops in temperature and water stress, c.g. kuo (eds.). tainan, taiwan. pp. 115–121 islam, m.r. 2003. eco-physiology of soil-flooding tolerance in mungbean. ph.d. thesis. bangabandhu sheikh mujibur rahman agricultural university, salna, gazipur-1706, bangladesh. islam, m.t. 1994. eco-physiological studies on photosynthesis and dry matter production in mungbean (vigna radiata l. wilczek). ph.d. thesis. kyushu university, fukuoka, japan. khadeja, s.s., a.a.c. masud, m.r. falguni, n. ahmed, k. rahman and m. hasanuzzaman. 2022. screening of soybean genotypes for waterlogging stress tolerance and understanding the physiological mechanisms. adv. agric. 2022: 544665. kyu, k.l., a.i. malik, t.d. colmer, k.h.m. siddique and w. erskine. 2021. response of mungbean (cvs. celera ii-au and jade-au) and blackgram (cv. onyx-au) to transient waterlogging. front. plant sci. 12: 709102. lesk, c., p. rowhani and n. ramankutty. 2016. influence of extreme weather disasters on global crop production. nature. 529: 84–87. minchin, f.r., r.j. summerfield, a.r.j. eaglesham and k.a. stewart. 1978. effects of short-term waterlogging on growth and yield of cowpeas (vigna unguiculata). j. agric. sci. 90: 355-366. nawata, e., s. yoshinaga and s. shigenaga. 1991. effects of waterlogging duration on the growth and yield of yard long bean (vigna sinensis var. sesquipedalis). sci. hort. 48: 185-191. olorunwa, o.j., b. adhikari, a. shi and t.c. barickman. 2022. screening of cowpea (vigna unguiculata l.) genotypes for waterlogging tolerance using morpho-physiological traits at early growth stage. plant sci. 315: 111136. scott, h.d., j. deangulo, l.s. wood and d.j. pitts. 1990. influence of temporary flooding at three growth stages on soybeans. j. plant nutr. 13: 1045–1071. selina. a., e. nawata and t. sakuratani. 2022. effect of waterlogging at vegetative and reproductive growth stages on photosynthesis, leaf water potential and yield in mungbean. plant prod. sci. 5(2): 117-123. singh, d.p. and b.b. singh. 2011. breeding for tolerance to abiotic stresses in mungbean. j. food legum. 24(2): 83–90. tomooka, n., c. lairungreang, p. nakeeraks, y. egawa and c. thavarasook. 1991. production of mungbean and black gram. in: mungbean and the genetic resources. taro, japan.p. 3. umaharan, p., r.p. ariyanayagam and s.q. haque. 1997. effect of short-term waterlogging applied at various growth phases on growth, development and yield in vigna unguiculata. j. agr. sci. 128: 189198. walelign, w. and a. berhanu. 2015. physio-agronomic response of mungbean (vigna radiata l. wilczek) genotypes to waterlogging. ethiop. j. appl. sci. technol. 5(2): 49-69. wang, m., q. zheng, q. shen and s. guo. 2013. the critical role of potassium in plant stress response. int. j. mol. sci. 14: 7370–7390. wondimagegne, s., h.m. shelton and h.b. so. 1992. tolerance of some subtropical pasture legumes to waterlogging. trop. grassl. 26: 187-195. yadav, r.s. and h.k. saxena. 1998. response of waterlogging on growth and seed yield of mungbean (vigna radiata l. wilczek). ind. j. plant physiol. 3: 71-72. microsoft word 7. baj-474e bangladesh agron. j. 2024, 26(2): 49-55 increasing cropping intensity, productivity and profitability through improved cropping pattern against farmers’ existing cropping pattern at madhupur, tangail m.a.h. khan1*, m.m. rahman1, t. tasmima1, and f. begum2 1on-farm research division, bangladesh agricultural research institute, tangail, bangladesh, 2oilseed research centre, agricultural research institute, joydebpur, bangladesh. *corresponding author, email: helim1367@gmail.com (received: 13 march 2024, accepted: 03 june 2024) keywords: rice equivalent yield, harvest index, profitability, efficiency and gross return abstract an on-farm trial was conducted at the farmers’ field of madhupur under on-farm research division, bangladesh agricultural research institute, tangail during 2021-22 and 2022-23 to develop improved cropping pattern mustard (var. bari sarisha-18)-t. aus (var. brri dhan48)-t. aman (var. brri dhan87) and to compare its productivity and profitability against farmers existing cropping pattern fallow-boro (var. brri dhan29)-t. aman (var. brri dhan49) by inclusion of mustard (var. bari sarisha-18)-t. aus (var. brri dhan48) and t. aman (var. brri dhan87) with improved management practices. the experiment was laid out in a randomized complete block design with six dispersed replications. two cropping patterns viz., improved cropping pattern (mustard-t. aus-t. aman) and farmers’ existing cropping pattern (fallow-boro-t. aman) were the treatment variables of the experiment. the unit plot size was 1000-1200 m2. the result of the study showed that three crops could be grown successfully in sequence in the tested site. mean rice equivalent yield of improved cropping pattern was 16.95 t ha−1 which was 54 % higher over existing cropping pattern (11.01 t ha−1). besides, land utilization index, harvest index and profitability of improved cropping pattern was higher than farmers’ existing cropping pattern. the mean gross return (tk. 523830 ha−1) and gross margin (tk. 334281 ha−1) were higher in improved cropping pattern compared to farmers’ existing cropping pattern with only 21% extra cost. the marginal benefit cost ratio (4.44) was also indicated by the superiority of the improved cropping pattern over the farmers’ existing cropping pattern. introduction bangladesh is almost self-sufficient in rice production but other food production such as oil crops, pulses, wheat and vegetables etc. are still largely deficient. mustard is one of the rabi crops in bangladesh though the largest area is still under t. aman rice cultivation during monsoon season. however, most of the aman rice area is covered with long duration t. aman varieties which causes a delay in mustard crop sowing, resulting in reduced yield. the present cropping intensity of the country is 198%. the urgent need is to produce more food to feed the teeming populations. food requirements are estimated to have doubled in the next 25 years. under such a situation, it is very important to improve the existing cropping pattern. there are some scopes of increasing cropping intensity from existing level of 198% by improving existing cropping patterns by incorporating short duration crops viz., mustard, aus rice, potato, and pulses in the rice-based cropping system (khatun et al., 2019). a cropping pattern is the yearly sequence, temporal and spatial arrangement of crops in each land area. the cropping pattern and the changes therein depend on many factors like climate, soil type, rainfall, agricultural technology, availability of irrigation facilities and other inputs, marketing and transport facilities and growth of agro-industries (gadge, 2003). bangladesh agricultural research institute (bari) has developed high yielding brown seeded mustard (brassica napus) variety bari sarisha-18 whose yield potential is 30-40% higher than bari sarisha-14 and have been recommended for mustard-t.aus-t.aman cropping sequence. inclusion of this new variety of mustard with growth duration of 95-100 days in between short duration t. aman rice (115-120 days) and t. aus rice can create 50 khan et al. opportunity to fit in the mustard-t. aus-t. aman cropping sequence. there are 10 major cropping patterns which are practiced by the farmers’ of tangail region, among which fallow-boro-t. aman is one of the major cropping patterns under irrigated high and medium high land of madhupur upazila, tangail. this pattern covers around 44% of the net cropped area (dae, 2021). after the harvest of t. aman and before transplanting of planting of boro the land remains fallow for around 3 months. mustard is a high value crop which can be easily grown in between two crops. boosting up crop production, replacement of crop varieties needs to be essential, which is possible, if short duration t. aman rice variety is included in the pattern. overall productivity as well as profitability of the farmers could be increased considerably by introducing modern varieties and improved management practices. several reports on different cropping pattern are available in bangladesh and abroad (nazrul et al., 2013; khatun et al., 2019) but little efforts have been made for on-farm evaluation of the improved technologies of mustard-t. aus-t. aman cropping pattern. the study was therefore initiated with a view to finding out the agroeconomic performance of an improved package of technologies over the existing farmers’ practices. therefore, the present study was designed to evaluate the productivity, profitability and increasing cropping intensity by inclusion of mustard-t. aus-t. aman rice cropping pattern in tangail region. materials and methods the trial was conducted at the farmers’ field of madhupur under on-farm research division, bari, tangail during 2021-22 and 2022-23 to increase cropping intensity, productivity and profitability of the farmers by inclusion of mustard (var. bari sarisha-18)-t. aus (var. brri dhan48) and t. aman (var. brri dhan87) in the existing cropping system fallow-boro (var. brri dhan29)-t. aman (var. brri dhan49). the experimental site belongs to madhupur tracts agro-ecological zone (aez-28) of tangail. the geographical position of the experimental site is at approximately 24°64ʹ n latitude and 90°09ʹ e longitude with an altitude of 19 m above sea level. the land was medium high, and the soil of the study area was clay loam to clay in texture with well drainage system and almost acidic in reaction having ph range of 4.3 to 6.5. maximum rainfall was received during the months of april to september. the highest temperature (33.9°c) in august and the lowest in december (10.1°c). the relative humidity was the highest (84.5%) in august and the lowest (75.2%) in march. monthly mean maximum and minimum air temperature (31.9 and 19.3°c), total rainfall (2018 mm) and relative humidity (82.7%) were prevailing during the study period. the experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. two cropping patterns viz., improved cropping pattern and farmers’ existing pattern were the treatment variables of the experiment. the unit plot size was 1000-1200 m2. mustard was grown during rabi season, and it was the first crop of the sequence. fertilizer management was followed by (ahmmed et al., 2018) and intercultural operations like weeding, irrigation and pest management were done to support the normal growth and development of the crops. mustard var. bari sarisha-18 was seeded as broadcast method @ of 6 kg ha−1. the crop was sown during 10 to 19 november 2021 and 14 to19 november 2022 and harvested during 16 to 25 february 2022 and 19 to 24 february 2023, respectively. t. aus rice was the second crop of the sequence. seedlings of rice were grown in adjacent plot and transplanting was done with 30 to 35 days old seedlings of rice var. brri dhan48 at a spacing of 20 cm × 15 cm during 20 to 25 april 2022 and 18 to 24 april 2023. t. aus rice was harvested during 06 to 10 july 2022 and 02 to 07 july 2023 in two consecutive years. rice plants were harvested at 30 cm height from soil surface and remaining parts of the plants were incorporated in soil. t. aman rice was the third crop of the sequence. seedlings of rice were grown in an adjacent plot and transplanting was done with 30 to 35 days old seedlings of t. aman rice var. brri dhan87 were transplanted with 20 cm × 15 cm during 25 to 28 july 2022 and 22 to 27 july 2023 in two consecutive years. t. aman rice was harvested during 24 to 27 october 2022 and 23 to 28 october 2023 in two successive years. t. aman rice plant was harvested at 15 cm from soil surface and remaining parts of the plants were incorporated in soil. increasing cropping intensity, productivity and profitability through improved cropping pattern 51 data on the yield of various crops in sequences were recorded and converted to t ha−1. the data of farmer's practice was recorded from adjacent farmers’ plots. agronomic performance like field duration, rice equivalent yield (rey), productivity and land utilization index (lui) of cropping patterns were calculated. rice equivalent yield: for comparison between crop sequences, the yield of every crop was converted into rey based on prevailing market price of individual crop (verma and modgal, 1983). rice equivalent yield (rey) was computed as yield of individual crop multiplied by market price of that crop divided by market price of rice. rey (t ha−1) = yield of individual crop × market price of that crop market price of rice productivity: production efficiency value in terms of kg ha−1day−1 was calculated by total main product in a cropping pattern divided by total duration of crops in that pattern (tomar and tiwari, 1990). production efficiency (kg ha−1day−1) =∑∑ where, yi= yield (kg) of ith crop, di= duration (day) of ith crop of the pattern and i= 1, 2, 3, 4 land utilization index it was worked-out by taking total duration of crops in an individual cropping pattern divided by 365 days (rahman et al. 1989). it was calculated by the following formula: lui (%) =d1+d2+d3+d4 365 × 100 where d1, d2, d3 and d4 the duration of 1st, 2nd, 3rd and 4th crop of the pattern. harvest index (hi) it is the ratio of economic yield and total biological yield of aboveground plant materials. the grain and stover should be at the same moisture content. it has been calculated as per following equation (rahman et al., 1989). hi (%) = economic yield biological yield ×100 marginal benefit cost ratio marginal benefit cost ratio was done based on prevailing market price of the commodities. the inputs used included seed, fertilizer, labour and insecticides. the mbcr of the farmer’s prevalent pattern and any replacement for it can be computed as the marginal value product (mvp) over the marginal value cost (mvc). the marginal of prevalent pattern (f) and any potential replacement (e) which was computed as (cimmyt, 1988). mbcr = gross return ( ) gross return ( ) tvc ( ) tvc ( ) = mvp mvc where tvc= total variable cost results and discussion crop management crop management practices include date of sowing/transplanting, date of harvesting, fertilizer dose used, field duration and turnaround time etc. of improved and existing cropping pattern are shown in table 1. the mean crop field duration of mustard, t. aus and t. aman rice under improved cropping pattern mustard (var. bari sarisha-18)-t. aus (var. brri dhan48)-t. aman rice (var. brri dhan87) were 99, 75 and 92 days, respectively while, in existing cropping pattern fallowboro (brri dhan29)t. aman rice (brri dhan49) were 120 and 102 days for boro and t. aman, respectively. total field duration of improved cropping pattern and existing cropping pattern were 262-267 and 219-225 days, respectively. the crop duration of t. aman rice under existing cropping pattern was higher (101-103 days) than that of improved cropping pattern (91-92 days) due to use of long duration brri dhan49 52 khan et al. variety in t. aman. but in improved cropping pattern, short duration of t. aman rice (brri dhan87) was cultivated, and it was harvested during 23-28 october in both years. after harvesting t. aman rice mustard was easily sown in optimum time. turnaround time for improved and existing cropping patterns were 98-103 and 140-146 days, respectively. table 1. agronomic parameters of farmers’ existing pattern and improved pattern at mlt site madhupur, tangail during 2021-22 and 2022-23 parameters years farmers’ pattern improved pattern crop 2021-22 2022-23 fallow fallow boro boro t. aman t. aman mustard mustard t. aus t. aus t. aman t. aman variety 2021-22 2022-23 fallow fallow brri dhan29 brri dhan29 brri dhan49 brri dhan49 bari sarisha18 bari sarisha18 brri dhan48 brri dhan48 brri dhan87 brri dhan87 sowing/ planting time 2021-22 2022-23 fallow fallow 15-19 jan. 10-15 jan. 15-19 jul. 12-16 jul. 10-16 nov. 14-19 nov. 20-25 apr. 18-24 apr. 25-28 jul. 22-27 jul. seedling age (days) 2021-22 2022-23 fallow fallow 40-45 40-45 30-40 30-40 30-40 30-40 30-35 30-35 spacing (cm) 2021-22 2022-23 fallow fallow 20 × 15 20 × 15 20 × 15 20 × 15 broadcast broadcast 20 × 15 20 × 15 20 × 15 20 × 15 fertilizer dose (npksznb kg ha−1) 2021-22 2022-23 fallow fallow 140-15-30-0-3 140-15-30-0-3 74-12-40-10-3 74-12-40-10-3 90-35-4226-2-2 90-35-4226-2-2 140-15-60-15-3 140-15-60-15-3 70-15-3510-4 70-15-3510-4 harvesting time 2021-22 2022-23 fallow fallow 12-16 may. 12-15 may 24-28 oct. 23-27 oct. 16-25 feb. 19-24 feb. 06-10 jul. 02-07 jul 24-27 oct. 23-28 oct. field duration (days) 2021-22 2022-23 fallow fallow 118 122 101 103 100 97 75 74 92 91 turnaround time (days) 2021-22 2022-23 fallow fallow 86 79 60 61 20 22 58 59 20 22 grain seed−1 and by-product yield grain seed−1 and by-product yield of the study have been presented in table 2. seed yield of bari sarisha-18 was 2.19 and 2.27 t ha−1 and stover yields were 2.29 and 2.37 t ha−1 in two successive years, respectively. two years average result showed that seed and stover yield of bari sarisha-18 in improved cropping pattern was 2.23 t ha−1 and 2.39 t ha−1. the grain yield of t. aus rice was 4.85 t ha−1 in 1st year and 4.93 t ha−1 in 2nd year whereas t. aman rice grain yields were 5.63 and 5.74 t ha−1 in 1st and 2nd years. mean grain and straw yields of t. aus rice were 4.89 and 4.94 t ha−1. two years average, grain and straw yields of t. aman rice (brri dhan87) were 5.69 and 5.83 t ha−1 in improved cropping pattern, respectively which was 26 and 25% higher than existing pattern t. aman rice (brri dhan49) due to change of variety with improved production technologies. similar results were also obtained by (nazrul et al. 2013). farmers’ pattern gave lower yield due to imbalance use of fertilizers and poor management practices. it was revealed that the entire component crops of mustard-t. aus-t. aman rice cropping pattern under improved practices (ip) gave higher yield as well as by-product yield in two consecutive years. inclusion of bari sarisha-18, brri dhan48 and brri dhan72 with improved production technologies increased the total yield over the farmers existing practice. similar results were also obtained by (nazrul et al., 2013). table 2. grain/seed yield and by-product of farmers cropping patterns and improved cropping pattern at mlt site madhupur, tangail during 2021-22 and 2022-23 parameters years farmers’ pattern improved pattern increasing cropping intensity, productivity and profitability through improved cropping pattern 53 fallow boro t. aman mustard t. aus t. aman grain seed−1 yield (t ha−1) 2021-22 6.42 4.51 2.19 4.85 5.63 2022-23 6.53 4.55 2.27 4.93 5.74 average 6.48 4.53 2.23 4.89 5.69 byproduct yield (t ha−1) 2021-22 6.72 4.60 2.29 4.89 5.79 2022-23 6.90 4.70 2.37 4.99 5.87 average 6.81 4.65 2.39 4.94 5.83 rice equivalent yield total productivity of a cropping system was evaluated in terms of rey and it was calculated from yield of component crops. the mean higher rice equivalent yield (16.95 t ha−1) was recorded with the improved cropping system over farmer’s traditional cropping system (table 3). rice equivalent yield increased by 54% in improved cropping pattern due to inclusion of bari sarisha-18 and new high yielding varieties of rice with improved production technologies for the component crops. the lower rice equivalent yield (11.01 t ha−1) was obtained in the farmer’s pattern due to two crops boro and t. aman rice with traditional management practices. it is evident from the above findings that improved cropping pattern gave higher yield compared to existing farmers’ pattern. similar results were obtained by nazrul et al. 2017. production efficiency mean maximum production efficiency (49.69) in terms of kg ha−1 day−1 was obtained from farmer’s existing cropping pattern which was 3.03% higher over improved cropping pattern (table 3). production efficiency of improved cropping pattern was found to be 47.45 and 49.02 kg ha−1 day−1 in two consecutive years while in existing cropping pattern it was found to be 49.91 and 49.46 kg ha−1 day−1, respectively. the production efficiency was lower in improved cropping pattern might be due to inclusion of long duration mustard variety as a result average total duration was (43 days) higher than farmer’s existing pattern. the lower production efficiency was observed in improved pattern (table 3). the result indicates that the crops remained in the field for longer time leading to lower production per day. on the contrary, crops remain standing in the field for a shorter time in farmer’s practices, leading to higher production efficiency. land utilization index land use efficiency is the effective use of land in a cropping year, which mostly depends on crop duration. the average land utilization index indicated that improved cropping pattern used the land for 72.74% period of the year whereas farmer’s pattern used the land for 60.68% period of the year (table 3). the land utilization index was about 20% higher in improved cropping pattern than farmer’s practice due to improved pattern occupied the land for longer duration (265 days) than farmer’s pattern (222 days) in a year. this higher land use efficiency in improved cropping pattern is due to cultivation of three component crops in the pattern. harvest index improved cropping pattern mustard (var. bari sarisha-18) – t. aus (var. brri dhan48) t. aman rice (var. brri dhan87) recorded the higher hi (49.43%) over existing cropping pattern fallow boro (var. brri dhan29) t. aman rice (var. brri dhan49). the hi of improved cropping pattern had higher value due to inclusion mustard, t. aus and t. aman varieties which contributed the higher economic and biological yield. table 3. rice equivalent yield, production efficiency, land utilization index and harvest index of farmers’ practices and improved pattern at mlt site madhupur, tangail during 2021-22 and 2022-23 54 khan et al. year pattern rice equivalent yield (t ha−1) production efficiency (kg ha−1 day−1) land utilization index (%) harvest index (%) 2021-22 fp 10.93 49.91 60.00 49.12 ip 16.74 47.45 73.15 49.41 2022-23 fp 11.08 49.46 61.37 48.85 ip 17.16 49.02 72.33 49.45 mean fp 11.01 49.69 60.68 48.99 ip 16.95 48.23 72.74 49.43 note: ip= improved pattern and fp=farmers’ pattern profitability analysis the cost and return analysis were done based on prevailing market price during the crop season as shown in table 4. table 4. cost and return analysis of farmers’ and improved cropping pattern cropping pattern at mlt site madhupur, tangail during 2021-22 and 2022-23 year pattern gross return (tk ha−1) total variable cost (tk ha−1) gross margin (tk ha−1) mbcr 2021-22 fp 373180 155990 217190 4.35 ip 517500 189166 328334 2019-20 fp 378800 156445 222355 4.52 ip 530160 189932 340228 mean fp 375990 156218 219772 4.44 ip 523830 189549 334281 note: ip= improved pattern and fp=farmers’ pattern; unit price (tk. kg−1): mustard =80/-, boro rice =30/-, t. aus rice =26/-, t. aman rice = 30/-, stover=2/-, and rice straw=4/ the study revealed that mean gross return of the improved and farmers’ pattern was tk 523830 and tk 375990 ha−1, respectively. the mean gross return of improved cropping pattern was 39% higher than farmers’ existing pattern and it might be due to inclusion of high yielding mustard, t. aus and t. aman rice varieties. the mean total variable cost of the improved and farmers’ existing cropping pattern was tk. 189549 ha−1 and tk 156218 ha−1, respectively. about 52% higher gross margin (tk 1334281 ha−1) was calculated at improved pattern over farmer’s existing cropping pattern (tk 219772 ha−1). the mean mbcr was found 4.44 which indicated the superiority of improved cropping pattern over farmer’s existing cropping pattern. conclusion the total crop productivity (in terms of rey), production efficiency and profitability of improved cropping pattern mustard (var. bari sarisha-18)–t. aus (var. brri dhan48)-t. aman rice (var. brri dhan87) were much higher than that of existing cropping pattern, fallowboro (var. brri dhan29)-t. aman rice (var. brri dhan49) due to inclusion of hyv mustard, t. aus and t. aman rice varieties. thus, improved cropping pattern mustard (var. bari sarisha-18)–t. aus (var. brri dhan48)t. aman (var. brri dhan87) is economically as well as agronomically suitable technology. this improved cropping pattern could be demonstrated for large scale production to exhibited areas in the high and medium high land and similar areas in bangladesh with the collaboration of department of agricultural extension (dae) and bari for higher impact. acknowledgement increasing cropping intensity, productivity and profitability through improved cropping pattern 55 the authors are grateful to the respected authority for their financial support to the research work under the project “enhance production of oil seed crops (bari part).” the authors also thankfully acknowledge office staff and farmers who participated in this study for providing their valuable time during the study period. references ahmmed, s., m. jahir uddin, s. razia, r.a. begum, j.c. biswas, a.s.m.m. rahman, m.m. ali, k.m.s. islam, m.m. hossain, m.n. gani, g.m.a. hossain and m.a. satter. 2018. fertilizer recommendation guide2018. bangladesh agricultural research council (barc), farmgate, dhaka. pp. 223. cimmyt. 1988. international maize and wheat improvement centre. from agronomic data to farmer recommendations: an economic training manual. international maize and wheat improvement centre, mexico, d.f. pp. 1-79. dae. 2021. department of agriculture extension. paper presented in the regional research extension review and program planning workshop at bangladesh agricultural research institute, gazipur-1701. gadge, s.s. 2003. influence of changes in cropping pattern on farmers' economic status. indian j. ext. edu. 39(1&2): 99-101. khatun, m.u.s., z. ferdous, z. haque, m.a.u. alam, m. hasan and m.k. islam. 2019. increasing cropping intensity of fallow-boro-t. aman cropping pattern with inclusion of mustard in tista mender floodplain soil. progress. agric. 30(4): 360-370. nazrul, m.i., m.k. hasan and m.r.i. mondal. 2017. production potential and economics of mungbean in rice-based cropping pattern in sylhet region under aez-20. bangladesh j. agril. res. 42(3): 413-424. nazrul, m.i., m.r. shaheb, m.a.h. khan and a.s.m.m.r. khan. 2013. on-farm evaluation of production potential and economic returns of potato-rice based improved cropping system. bangladesh agron. j. 16(2): 41-50. rahman, m.m., m.h. khan, r.n. mallick and r.e hudgens. 1989. guidelines for farming systems research methodology. bangladesh agricultural research council, farmgate, dhaka. pp. 42. verma, s.p and s.c. modgal. 1983. production potential and economics of fertilizer application as resources constraints in maize, wheat crop sequence. himachal j. agric. res. 9(2): 89-92. bangladesh agron. j. 2025, 28(2): 57-60 effect of lime on yield of wheat and maize in the acidic soils of farmers’ field of northern bangladesh m. m. hossain1*, t. islam1, m. a. a. mamun1, m. s. n. mandal2, a. hossain3, m. m. hoque4, m. a. hakim5, and m. m. bazzaz6 1on-farm research division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur5200 2genetic resource and seed division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur-5200 3soil science division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur-5200 4maize breeding division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur-5200 5wheat breeding division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur-5200 6agronomy division, bangladesh wheat and maize research institute (bwmri), nashipur, dinajpur-5200 *corresponding author, email: mobarak.hossain@bwmri.gov.bd (received: 20 october 2025, accepted: 22 november 2025) keywords: soil ph, acidity, alkalinity, yield, mbcr abstract on-farm experiments were conducted on six farms in thakurgaon and panchagarh of northern bangladesh during the 2022-23 and 2023-24 rabi seasons. the experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. the unit plot size was 400 square meters. wheat (bari gom 33) was sown in a continuous pattern, with rows spaced 20 cm apart while the maize (bwmri hybrid maize 2) planting was at a spacing of 60 cm × 25 cm. seeding of both the crops took place on december 20 and 22 in thakurgaon and december 4 and 5 in panchagarh during two years, respectively. the treatment, dolomite lime, was applied at 4 kilograms decimal−1 seven days before the final land preparation. seed rate and fertilizer dose were maintained as per the recommendation of bwmri, dinajpur. the ph of the initial and post-harvest soil was determined at the soil science laboratory, bwmri. dolomite increased the soil ph to 5.68 from 4.99 in the wheat field and 5.85 from 4.94 in the maize field. due to dolomite application the yield of wheat was increased by 25% (4.84 t ha−1) and that in maize by 14% (12.26 t ha−1) compared to the control (3.87 t ha−1 and 10.81 t ha−1 for wheat and maize, respectively). the liming also increased the mbcr by 23 and 34% in wheat and maize over no liming, respectively. introduction soil ph, which measures acidity or alkalinity, significantly affects crop growth and yield. the ph scale of soil typically ranges from 4.0 to 8.0, with highly acidic soil having a ph below 4.5, moderately acidic soil between 4.5 and 5.5, and mildly acidic soil between 5.6 and 6.5. neutral soil has a ph between 6.6 and 7.3. soil ph directly influences the availability of essential nutrients for plants, which are vital for their growth. crops depend on 17 essential nutrients, with carbon, oxygen, and hydrogen obtained from air and water, while the remaining nutrients come from the soil. when soil ph is within the mildly acidic to mildly alkaline range (5.6-7.3), nutrients become more accessible to plants, promoting healthy growth and higher yields (barrow & hartemink, 2023; o’ kennedy, 2022). in bangladesh, the total area of cropland spans approximately 8.5 million hectares, of which about 2.78 million hectares are highly acidic (ph below 4.5), and approximately 3.64 million hectares are moderately acidic (ph between 4.5 and 5.5). in total, this accounts for nearly effect of lime on yield of wheat and maize in the acidic soils of farmers’ field 58 46% of the country's agricultural land. the high acidity of these soils limits crop growth, reducing yield due to nutrient deficiencies, particularly phosphorus, calcium, magnesium, and molybdenum, while the levels of toxic elements such as aluminum, iron, and manganese are elevated (hosna et al., 2024). regions in bangladesh, including greater rangpur, dinajpur, sylhet, chittagong, and the barendra and madhupur garh areas, experience significant soil acidity, affecting agricultural productivity. to ensure optimal crop yields, it is essential to neutralize soil acidity and maintain a ph between 5.6 and 7.5. in northern bangladesh, the deficiency of calcium, magnesium, and other alkaline elements exacerbates soil acidity. approximately 2.1 million hectares of land have low to very low calcium levels, and around 1.1 million hectares suffer from low to very low magnesium levels. applying recommended doses of dolomite (caco₃.mgco₃) can effectively reduce acidity and raise the ph to a suitable level for crop growth, as dolomite contains 20% calcium and 11% magnesium (hasan et al., 2020). wheat and maize are the 2nd and 3rd critical staple crops in bangladesh, contributing significantly to food security and the agricultural economy. wheat is predominantly cultivated in the northern and western regions, while maize, due to its high yield potential and versatility, has gained increasing popularity all over bangladesh. both crops are extensively grown in these regions, where the soils are often acidic (ph 4.5 to 5.5), presenting challenges to crop production. soil acidity hinders nutrient availability, microbial activity, and root growth. one of the most effective methods to mitigate soil acidity is lime application, which neutralizes acidity, reduces the toxicity of aluminum (al), iron (fe), and manganese (mn), improves nutrient availability, and enhances soil structure. this study was undertaken to evaluate the effect of lime on yield performance of wheat and maize. materials and methods the experiment was conducted in thakurgaon and panchagarh district (aez 1: old himalayan piedmont plain) during rabi 2022-23 and 2023-24 seasons. the experiment was laid out in a randomized complete block design (rcbd) with six dispersed replications. land was medium high land, i.e., above normal flood level. rainwater drains quickly, and the soils dry out very early in the dry season. the soil sample has a composition of 67.7% sand, 15.36% silt, and 16.97% clay, indicating a sandy texture with a relatively high proportion of sand. the sand-to-silt ratio is 4.4, suggesting that sand is significantly more abundant than silt, while the silt-to-clay ratio of 0.91 indicates a slightly higher amount of silt compared to clay. the unit plot size was 400 sq. m (20m x 20m). the wheat variety, bari gom 33, and maize variety, bwmri hybrid maize 2, were used in the experiment. wheat seeds were sown as continuous seeding with line to line 20 cm distance, and for maize variety, spacing was maintained at 60 cm and 25 cm between rows and plants. the ph of the soil was examined before sowing at the soil science division, bwmri. treatment dolomite (powered) was applied at 4 kg per decimal one week before final land preparation as recommended by soil resource development institute (srdi). seed rate, fertilizer dose and cultural practices were maintained as per the recommendation of bwmri. crops were harvested at full maturity. grain yield was adjusted to 14% moisture content. the combined analysis of two years data on all measurement parameters was analyzed statistically using the star software (irri, 2013), and mean comparisons were done using dmrt at the 5% level (gomez & gomez, 1984). results and discussion the comparative yield performance of wheat and maize crops with dolomite and without dolomite application in the thakurgaon and panchagarh districts are presented in table 1. the 59 hossain et al. average yield of wheat across the two districts improved in two years following the application of dolomite. initially, the mean ph of the wheat fields was 4.99, which increased to 5.68 after applying dolomite at 4 kg per decimal. in the fields treated with dolomite, the wheat yield reached 25% higher (4.84 t ha−1) than the control (3.87 t ha−1). the average ph of the maize field was 4.94, which increased to 5.85 following the application of dolomite at a rate of 4 kg per decimal. the maize yield was 14% more in the dolomite-treated field, reaching 12.26 t ha−1, compared to 10.81 t ha−1 in the untreated field. the application of dolomite lime is reported to neutralize soil ph effectively, which significantly reduces soil al, fe, and mn toxicity (data not shown). moreover, it increases base saturation, p and mo availability of acid soils, and improves soil structure which might have cumulatively improved the grain yield of wheat and maize in this study. increase in yield in the lime treatment consequently increased the marginal benefit cost ratio (mbcr) by about 23 and 34% in wheat and maize, respectively. table 1. effect of dolomite on the soil ph and the yield of wheat and maize (two years’ mean data of 2022-23 and 23-24 rabi seasons) treatments wheat maize ph yield (t ha−1) mbcr ph yield (t ha−1) mbcr control 4.99b 3.87b 1.19b 4.94b 10.80b 1.87b dolomite 5.68a 4.84a 1.47a 5.85a 12.26a 2.51a lsd (0.05) 0.47 0.34 0.21 0.58 1.14 0.18 cv (%) 6.36 5.50 3.84 7.61 7.02 4.47 mbcr: marginal benefit cost ratio; lsd: least significant difference; cv: co-efficient of variance. means with similar letters are significantly identical it was evident from the results that dolomite liming markedly elevates both soil ph and crop yield in wheat and maize when compared to untreated control conditions. specifically, for wheat, the soil ph increased from 4.99 in the control to 5.68 with dolomite, resulting in a yield rise from 3.87 to 4.84 t ha−1. for maize, the soil ph enhancement from 4.94 (control) to 5.85 (dolomite) accompanied a notable yield jump from 10.8 t ha⁻1 to 12.26 t ha⁻1, with these differences confirmed as significant by the provided lsd values (0.34 for wheat and 1.14 for maize). these findings are corroborated with the previous research, which consistently reports that lime amendments, especially dolomite, improve yields by alleviating soil acidity, increasing the availability of essential nutrients such as calcium, magnesium, and phosphorus, and reducing the detrimental effects of toxic manganese prevalent in acid soils (agegnehu et al., 2021; hosna et al., 2024; sultana et al., 2009). such improvements in plant nutrition directly foster enhanced grain formation and overall productivity, mirroring reports from long-term field trials where dolomite liming led to yield increases of up to 37% in wheat and up to 50% in maize depending on soil and crop parameters. the critical role of nutrient availability, particularly calcium and magnesium supplied by dolomite, is regularly emphasized in the literature as a driver of better root health and nutrient uptake capacity in both wheat and maize. increased yield might have attributed to achieve the higher mbcr in the lime treated acidic soils in this study. additionally, liming is shown to lower the risk of manganese and aluminum toxicity, which is known to suppress plant growth and yield under acidic soil conditions (alemu et al., 2022; gitari et al., 2015; kibet et al., 2023). overall, the data and literature collectively advocate the widespread adoption of dolomite lime application in the acidic soils at the rate of four kilograms per acre in every four years as recommended by soil resource development institute (srdi). effect of lime on yield of wheat and maize in the acidic soils of farmers’ field 60 conclusion based on the experimental results it is concluded that application of lime in acidic soils increases maize and wheat productivity and economic return substantially in the northern bangladesh. references agegnehu, g., t. amede, t. erkossa, c. yirga, c. henry, r. tyler, m. g. nosworthy, s. beyene and g. w. sileshi. 2021. extent and management of acid soils for sustainable crop production system in the tropical agroecosystems: a review. acta agric. scand sect. b soil plant sci. 71(9): 852–869. alemu, e., y.g. selassie and b. yitaferu. 2022. effect of lime on selected soil chemical properties, maize (zea mays l.) yield and determination of rate and method of its application in northwestern ethiopia. heliyon. 8(1): e08657. barrow, n.j. and a.e. hartemink. 2023. the effects of ph on nutrient availability depend on both soils and plants. plant soil 487(1): 21–37. gitari, h.i., b.e. mochoge and b.o. danga. 2015. effect of lime and goat manure on soil acidity and maize (zea mays) growth parameters at kavutiri, embu countycentral kenya. j. soil sci. environ. manage. 6(10): 275–283. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research, international rice research institute, los banos, philippines, john wiley and sons, new york. p. 680. hasan, m.n., m.a. bari and m.l. rahman. 2020. soil fertility trends in bangladesh 2010 to 2020. srsrf project. soil resource development institute, ministry of agriculture, dhaka, bangladesh. pp.84. hosna, k.t., m.m. rahman, s.g. al-solaimani, n.yeasmin, m.n. islam, m.h.a. el-wahed and n. muhammad. 2024. effect of liming on soil ph, nutrient availability, growth and yield of wheat in acidic soils of tista floodplain in bangladesh. int. j. plant soil sci. 36(10): 103–115. irri. 2013. international rice research institute. statistical tool for agricultural research (star) (2.0.1). biometrics and breeding informatics, pbgb division. los banos, laguna 4031, philippines. http://bbi.irri.org. kibet, p.k., j.n. mugwe, n.k. korir, m.w. mucheru-muna, f.k. ngetich and d.n. mugendi. 2023. granular and powdered lime improves soil properties and maize (zea mays l.) performance in humic nitisols of central highlands in kenya. heliyon. 9(6): e17286. o’ kennedy, s. 2022. soil ph and its impact on nutrient availability and crop growth. int. j. geogr. geol. environ. 4(2): 236–238. sultana, b.s., m.m.h. mian, m.r. islam, m.m. rahman, b.c. sarker and m.s. zoha. 2009. effect of liming on soil properties, yield and nutrient uptake by wheat. curr. world environ. 4(1): 39–47. bangladesh agron. j. 2022, 25(2): 129-137 impact of tobacco industry wastewater on germination and seedling growth of mungbean s.k. pramanik, n.j. nezu, t. siddiquea, d. roy and j.k. roy department of crop physiology and ecology, faculty of agriculture, hajee mohammad danesh science and technology university, dinajpur-5200 corresponding e-mail: pramaniksk100@gmail.com (received: 17 january 2023, accepted: 06 february 2023) keywords: mung bean, industrial wastewater, tobacco, germination, seedling growth abstract an experiment was conducted in the month of november, 2021 at crop physiology and ecology laboratory, hajee mohammad danesh science and technology university, dinajpur, bangladesh to study the impact of tobacco industry wastewater on germination and early seedling traits of five mung bean accessions (bd-10022, bd-10023, bd-10024, bd-10026 and bd-10027) following factorial completely randomized design (crd) with three replications. mung bean accession, tobacco industry wastewater and their interaction significantly interacted on germination and seedling traits of mung bean. tobacco industry wastewater reduced the germination percentage, germination rate and co-efficient of germination but insisted longer shoot and root as well as escalated the seedling dry weight of mung bean as compared to tap water. among the five mung bean accessions, bd-10024 and bd-10027 performed comparatively better performance regarding germination and seedling traits, respectively under wastewater conditions. introduction the scarcity of freshwater is increasing day by day due to the increasing demand of water in domestic, municipal, agricultural and industrial sectors, especially in the developing countries of the world (undp, 2016). due to the shortage of freshwater resources the use of industrial wastewater for growing agricultural crops is emerging (niroula, 2003; dash, 2012), particularly in arid and semi-arid regions (pramanik, 2021). industrial wastewater may contain organic matter, n, p, k, ca, caco3 and other essential plant nutrients which are beneficial for crop growth but heavy metal present in excess quantity affects germination of seed (mehta and bharadwaj, 2012). industrial wastewater significantly affects the seed germination and seedling growth of various crop species (huma et al., 2012; cabral et al., 2010; acharya, 2001). industrial wastewater at higher concentration significantly affects germination and growth of wheat (patil et al., 2020), rice (islam et al., 2017) and onion (pokharel et al., 2000). but there can be both beneficial and damaging effects of wastewater irrigation on crops (ramana et al., 2002; saravanamoorthy and kumari, 2007). therefore, it is necessary to study the impact of wastewater on crop production before recommending for irrigation (thamizhiniyan et al., 2009). the tobacco industry is one of the biggest industries in the world that generates and disposes large quantities of wastewater containing many chemical compounds like nicotine, glycogen, alcohol, absorbable organic halogens and exudates of tobacco leaves (sponza, 2002), which may be toxic to the flora (pramanik and sikder, 2020; pramanik, 2021), fauna, public health as well as environment (adenike, 2014; alabi et al., 2014). 130 pramanik et al. bangladesh is one of the most tobacco producing and consuming countries. tobacco industry is one of the largest industries in bangladesh and there are so many active firms of tobacco. tobacco is manufactured or processed by different steps where huge amount of wastewater are originated. for manufacturing of tobacco, first step is the tobacco production that does not contaminate the water. but in second step, nicotine, synthetic flavoring agents and residues of pesticides contribute to produce wastewater (chidambara and han, 2004). untreated or allegedly treated tobacco wastewater may contaminate seed germination and crop growth under irrigation as it contains significant amounts of heavy metals like arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc (sharma et al., 2004). in spite of the large quantities of wastewater generated by the tobacco industry which has been affecting the environmental and public health, there is little information on toxicity of that wastewater on different flora as well as on economic crop growth. mung bean (vigna radiata l.), self-pollinating grain legume belonging to the family fabaceae also known as the moong bean, mugdal or green gram is one of the most important pulse crops in bangladesh. being a short duration (<60 days) crop, it is an ideal legume for catch cropping, intercropping, and relay cropping. the crop is supporting food security by ensuring excellent and easily digestible protein source for humans especially for poor people where meat is lacking (bangar et al., 2019). the raw and mature seeds are rich in carbohydrates, protein, fibers, minerals, antioxidants and phenolics (guo et al., 2012) and has become one of the popular legumes in the tropic and sub-tropics for its rich nutritional components (thomas et al., 2004). mung bean grows mainly in rain-fed conditions at high temperatures (27-30°c) with low humidity and moderate rainfall ranging from 60 to 80 cm (bangar et al., 2019). in bangladesh, the barind tract region is the major mung bean cultivating area where warm and humid climate generally exist with comparatively little rainfall. despite being an economically important crop, the annual overall production (41000 mt) as well as average yield (0.93 mt ha-1) of mung bean (bbs, 2022) is low in bangladesh. the crop faces scarcity of water at different growth and developmental stages which ultimately loss of yield. therefore, one or two supplementary irrigation(s) is/are essential for successful production of mung bean in that region of bangladesh. in the northern part of bangladesh, most of the farmers face severe shortage of irrigation water during dry season. the lower socio-economic group of people living near the tobacco industry use tobacco industry effluent wastewater for cultivating different crops including mung bean without giving any concern on suitability of the water for irrigation. it is hypothesized that different toxic chemicals and heavy metals present in tobacco industry wastewater could interfere in germination, growth and development of mung bean. for the sake of that, the experiment was conducted to evaluate the impact of tobacco industry wastewater on germination and early seedling traits of some mung bean accessions. materials and methods the experiment was carried out at crop physiology and ecology laboratory, hajee mohammad danesh science and technology university, dinajpur, bangladesh in the month of november, 2021 with two factors viz. factor a: five mung bean accessions (bd-10022, bd-10023, bd10024, bd-10026 and bd-10027) and factor b: two irrigation water (i. tap water ii tobacco industry wastewater). the completely randomized design (crd) with three replications was followed to conduct the experiment. healthy seeds of five mung bean accessions were collected from bangladesh agricultural research institute (bari), gazipur. the wastewater samples were collected from the drainage system of three tobacco industries (akij tobacco industry ltd., abul khayer tobacco industry ltd. and british american tobacco bangladesh ltd.) situated in tobacco industry wastewater impacts on germination and growth of mungbean 131 rangpur city. samples were collected in plastic bottles that had been cleaned with hydrochloric acid (1:1) and then rinsed with tap water followed by rinsing with distilled water. the water samples collected from three industries were mixed thoroughly and considered as 100% wastewater. clean, air dried and sterilized petridishes (11cm diameter) were taken for germination test. twenty seeds of each accession were placed on filter paper sprinkled with respective treatment solution. before sowing, seeds were surface sterilized in 0.1% mercuric chloride solution for 30 seconds, and then were washed thoroughly with tap water followed by distilled water. each petridish containing the seeds was irrigated with respective treatment water throughout the experimental period. germination was counted at 24-hours interval and continued up to 6th day. a seed was considered germinated when plumule and radicle came out and larger than 2 mm long. the percentage of germination was counted at 6th day of placement of seeds. the rate of germination was calculated according to krishnasamy and seshu (1990) and co-efficient of germination was calculated using the formulae of copeland (1976). the length of shoot and root of seedling was recorded by centimeter scale at 8 days after placement. five seedlings from each petridish were sampled for shoot and root length. then the seedlings were dried separately at 70°c for 72 hours in an electric oven and weight was recorded with an electrical balance. the mean of length and dry weight were calculated for each treatment combination. data were analyzed by partitioning the total variance using statistix 10 program and the means were compared by tukey’s test at 5% level of probability. results and discussion germination characteristics percent germination, rate of germination and co-efficient of germination of mung bean seeds were significantly varied due to different accessions and wastewater (table 1 and 2). among the accessions, maximum germination percentage (95.61%) and highest rate of germination (94.17%) were noted in bd-10026 which was statistically similar with that of bd-10022 (93.77% and 93.12%, respectively). comparatively lower percentage of germination and rate of germination were observed in other accessions compared to bd-10022 and bd-10026. maximum co-efficient of germination (40.49) was calculated in bd-10022. lower but statistically similar co-efficient of germination of mung bean seeds were recorded in bd-10023 (40.13) and bd-10026 (39.95) whereas minimum value of the trait (34.41) was found in bd10024 followed by bd-10027 (36.77). lower percent germination (81.91%), germination rate (79.33%) and co-efficient of germination (35.44) compared to that of control (97.28%, 97.42%, and 41.26, respectively) indicates that the germination of mung bean seeds was inhibited by tobacco industry wastewater. the interaction effect of mung bean accessions and irrigation water indicated that significant reduction was observed in the germination percent of all mung bean accessions in different extends under tobacco industry wastewater. the maximum and statistically similar germination percentage and rate of germination of mung bean seeds were recorded under control condition except bd-10024 which was reduced at tobacco industry wastewater treatment. tobacco industry wastewater reduced percent germination by 9.03, 27.67, 3.66, 8.79 and 28.92%, while germination rate by 12.09, 31.67, 3.53, 11.67 and 32.23% in bd-10022, bd-10023, bd-10024, bd-10026 and bd-10027, respectively (table 2). the highest co-efficient of germination (44.85) was found in bd-10023 at control condition, whereas the lowest value of the trait (33.14) was recorded in bd-10027 under wastewater condition which was statistically at par with that of bd-10024 under same growing condition. tobacco industry wastewater 132 pramanik et al. reduced the trait by 12.44, 21.05, 6.66, 11.02 and 17.95 % in bd-10022, bd-10023, bd10024, bd-10026 and bd-10027, respectively (table 2). results reveal that bd-10024 performed better compared to other accessions in terms of germination capacity. table 1. effect of tobacco industry wastewater on germination of seeds of mung bean accessions treatments germination characteristics (mean ± se) germination (%) germination rate (%) co-efficient of germination mung bean accessions bd-10022 93.77±2.442 a 93.12±3.388 a 40.49±1.350 a bd-10023 86.17±6.511 bc 84.17±7.290 bc 40.13±2.335 a bd-10024 89.09±3.003 b 87.10±1.847 b 34.41±0.818 c bd-10026 95.61±2.609 a 94.17±3.581 a 39.95±1.423 a bd-10027 83.36±6.585 c 83.33±7.475 c 36.77±1.786 b level of significance ** ** ** critical value for comparison 3.4522 2.9430 0.9787 standard error for comparison 1.142 0.973 0.324 irrigation water control (tap water) 97.28±1.668 a 97.42±1.838 a 41.26±0.971 a wastewater 81.91±2.671 b 79.33±2.709 b 35.44±0.734 b level of significance ** ** ** critical value for comparison 1.5178 1.2939 0.4303 standard error for comparison 0.722 0.616 0.205 coefficient of variation (%) 2.21 1.91 1.46 in a column, values having same letter(s) did not differ significantly by tukey at p 5% level. ** indicates significantly different at 1% level of probability. se indicates standard error. table 2. interaction effect of tobacco industry wastewater and mung bean accessions on germination of mung bean mung bean accessions irrigation water germination percentage rate of germination co-efficient of germination % % change over control % % change over control % change over control bd-10022 control (tap water) 98.20 a -9.03 99.11 a -12.09 43.17 b -12.44 wastewater 89.33 b 87.12 b 37.80 d bd-10023 control (tap water) 100.00 a -27.67 100.00 a -31.67 44.85 a -21.05 wastewater 72.33 c 68.33 c 35.41 e bd-10024 control (tap water) 90.75 b -3.66 88.66 b -3.53 35.59 e -6.66 wastewater 87.43 b 85.53 b 33.22 f bd-10026 control (tap water) 100.00 a -8.79 100.00 a -11.67 42.28 b -11.02 wastewater 91.21 b 88.33 b 37.62 d bd-10027 control (tap water) 97.45 a -28.92 99.34 a -32.23 40.39 c -17.95 wastewater 69.27 c 67.32 c 33.14 f level of significance ** ** ** critical value for comparison 5.7866 4.9331 1.6404 standard error for comparison 1.615 1.376 0.458 coefficient of variation (%) 2.21 1.91 1.46 in a column, values having same letter(s) did not differ significantly by tukey at p 5% level. ** indicates significantly different at 1% level of probability. tobacco industry wastewater impacts on germination and growth of mungbean 133 however, the accession bd-10027 was found the most susceptible in terms of germination percentage and rate of germination, whereas bd-10023 was found the most susceptible accession in respect to co-efficient of germination at tobacco industry wastewater application. different degrees of germination capacity of mung bean seeds under wastewater application might be due to genetic variability of the crop (pramanik, 2021). tobacco industry wastewater knowingly declined the studied germination characteristics of mung bean accessions which might be due to the chemical fraction that leads to the inhibition of germination (bhalla et al., 1973). suseelamma and venkataraju (1994) reported that the inhibition of germination is dependent on the concentration of extract from cigarette tobacco leaf and also its entry to growing points of seedlings. another finding reported that allelochemicals acid and phthalate released from the smoke and tobacco leaf as well as from wastewater probably interfered the plant growth regulators during germination and inhibited germination as well as early seedling growth of plant (jianhua et al., 2012). our findings are very much consistent to findings of other researchers who reported that tobacco industry wastewater significantly hampered the germination characteristics of wheat (pramanik and sikder, 2020) and mung bean (pramanik, 2021). early seedling traits different mung bean accessions showed significant variation in their shoot length, root length, shoot to root ratio and dry weight of seedling (table 3). among the accessions, bd-10024 produced the longest shoot (9.91 cm), maximum seedling dry weight (14.95 mg plant-1) and showed maximum shoot to root ratio (2.66), whereas bd-10026 produced the highest root length (5.74 cm). the shortest shoot (7.42 cm) and shortest root (3.20 cm) were recorded in bd-10027 but the minimum shoot to root ratio (1.44) and minimum dry matter accumulation in seedling (11.97 mg plant-1) were recorded in bd-10026. achieved results on early seedling traits of mung bean accessions were significantly influenced by irrigation water except shoot to root ratio (table 3). mung bean accessions increased their shoot and root length, shoot to root ratio and seedling dry weight by 9.27 cm, 4.69 cm, 1.98 and 13.69 mg plant-1, respectively when germination of seed allowed in tobacco industry wastewater application as compared to that produced at control condition by 8.14 cm, 4.15 cm, 1.96 and 12.24 mg plant-1, respectively. table 3. impact of tobacco industry wastewater on early seedling traits of mung bean accessions treatments early seedling traits (mean ± se) shoot length (cm) root length (cm) shoot to root ratio seedling dry weight plant-1 (mg) mung bean accession bd-10022 8.85±0.345b 5.02±0.138b 1.76±0.135 c 11.99±0.365 c bd-10023 9.08±0.233b 4.40±0.157c 2.06±0.112bc 13.05±0.563 b bd-10024 9.91±0.428a 3.73±0.129d 2.66±0.152 a 14.95±0.415 a bd-10026 8.27± 0.214c 5.74± 0.250a 1.44±0.097 d 11.97± 0.360 c bd-10027 7.42±0.374d 3.20± 0.158e 2.32±0.107 b 12.88± 0.433 b level of significance ** ** ** ** critical value for comparison 0.4557 0.4429 0.3251 0.4769 standard error for comparison 0.1507 0.1465 0.1405 0.1577 growing media control 8.14±0.251 b 4.15±0.241 b 1.96±0.083 12.24±0.334 b waste water 9.27±0.260 a 4.69±0.262 a 1.98±0.104 13.69±0.341 a level of significance ** ** ns ** critical value for comparison 0.2003 0.1947 0.1142 0.2097 standard error for comparison 0.095 0.093 0.094 0.099 coefficient of variation (%) 3.00 5.75 1.46 2.11 in a column, values having same letter(s) did not differ significantly by tukey at p 5% level. ** indicates significantly different at 1% level of probability. ns indicates not significant. se indicates standard error. 134 pramanik et al. the shoot length, root length, shoot to root ratio and seedling dry weight plant-1 were also varied significantly by the interaction effect of mung bean accessions and irrigation water where tobacco industry wastewater considerably increased the seedling traits of mung bean in different extends compared to control condition except shoot to root ratio in bd-10023 and bd-10026. the interaction effect on early seedling traits of mung bean expressed that the longest shoot (10.69 cm), maximum shoot to root ratio (2.72) and the maximum seedling dry weight (15.66 mg plant-1) were recorded in bd-10024, while bd-10026 produced the longest root (6.20 cm) under wastewater condition which was statistically similar to root length (5.27 cm) produced by the same accession under control condition (table 4). the shortest shoot and root length 6.67 and 2.93 cm, respectively were observed in bd-10027 under control. minimum shoot to root ratio (1.32) were recorded in accession bd-10026 germinated at wastewater and minimum seedling dry weight (11.33 mg plant-1) were recorded in bd-10022 at control. table 4. interaction effect of tobacco industry wastewater and mung bean accessions on early seedling traits of mung bean mung bean accession growing media shoot length root length shoot to root ratio seedling dry weight cm % change over control cm % change over control % change over control mg % change over control bd-10022 control (tap water) 8.17 ef +16.65 4.83 bc +7.66 1.69 f +8.28 11.33 d +11.65 wastewater 9.53 b 5.20 b 1.83 e 12.65 c bd-10023 control (tap water) 8.75 cde +7.54 4.17 cde +10.79 2.09 d -2.39 12.17 c +14.46 wastewater 9.41 bc 4.62 bcd 2.04 d 13.93 b bd-10024 control (tap water) 9.12 bcd +17.21 3.53 ef +11.33 2.58 b +5.43 14.24 b +9.97 wastewater 10.69 a 3.93 de 2.72 a 15.66 a bd-10026 control (tap water) 7.98 f +7.14 5.27 a +17.65 1.51 g -12.58 11.36 d +10.74 wastewater 8.55 def 6.20 a 1.32 h 12.58 c bd-10027 control (tap water) 6.67 g +22.34 2.93 f +18.09 2.28 c +3.50 12.11 c +12.63 wastewater 8.16 ef 3.46 ef 2.36 c 13.64 b level of significance ** ** ** * critical value for comparison 0.7638 0.7424 0.1352 0.7994 standard error for comparison 0.213 0.207 0.1639 0.223 coefficient of variation (%) 3.00 5.75 1.46 2.11 in a column, values having same letter(s) did not differ significantly by tukey at p 5% level. **and * indicate significantly different at 1% and 5% level of probability, respectively. tobacco industry wastewater increased the seedling growth by 16.65, 7.54, 17.21, 7.14 and 22.34% for shoot length; 7.66, 10.79, 11.33, 17.65 and 18.09% for root length and 11.65, 14.46, 9.97, 10.74 and 12.63% for seedling dry weight in bd-10022, bd-10023, bd-10024, bd-10026 and bd-10027, respectively. considerable increment (8.28, 5.43 and 3.50%) in shoot to root ratio were found in bd-10022, bd-10024 and bd-10027, correspondingly but accession bd-10023 decreased the trait by 2.39% and bd-10026 by 12.58%. the meaningful tobacco industry wastewater impacts on germination and growth of mungbean 135 increment in the shoot and root length of mung bean seedlings under wastewater might be due to the organic matter content in industrial wastewater which accelerated more accumulation of dry matter in seedling of mung bean (messrouk et al., 2014). wastewater may trigger some growth stimulating enzymes during germination, which in turn increase the amount of hydrolyzates like glucose and amino acids required for growth of embryo axes (pramanik and sikder, 2020) that might be another possible reason for enhancement of early seedling growth. hossain et al. (2018) observed that irrigation with tobacco industry wastewater increased the shoot and root length in cucumber, radish and long yard bean seedlings under laboratory condition, similar facts might be happened in the present findings. tobacco industry wastewater significantly increased the shoot and root length as well as shoot and root dry weight in wheat seedlings (pramanik and sikder, 2020) and in mung bean seedlings (pramanik, 2021). these findings are very much congruent with the results of our present investigation. mojiri et al. (2013) also found increase in shoot and root length of lepidium sativum when irrigated with wastewater that consistent with our findings. conclusion the achieved findings from the present investigation support our hypothesis that the tobacco industry wastewater hinders the germination traits though leads to beneficial changes in early seedling traits to some extent. therefore, tobacco industry wastewater needs a thorough assessment for its suitability as irrigation water. among the studied accessions, bd-10024 showed comparatively better performance in relation to germination and bd-10027 performed better regarding seedling traits under wastewater treated condition. references acharya, i. 2001. effect of brewery industrial effluents on some agricultural crops and soil. m.sc. thesis. central department of botany, tribuvan university, kirtipur, kathmandu. adenike, a. 2014. microbiological, physicochemical and genotoxicological assessment of tobacco wastewater. adv. appl. sci. res. 5(3): 423-438. alabi, o.a., o.w. evi, y. precious, l. moruf and a.b. adekunle. 2014. tobacco industry wastewater-induced genotoxicity in mice using the bone marrow micronucleus and sperm morphology assays. cytologia 79(2): 215-225. bangar, p., a. chaudhury, b. tiwari, s. kumar, r. kumari and k. venkataramana. 2019. morphophysiological and biochemical response of mung bean (vigna radiata l. wilczek) varieties at different developmental stages under drought stress. turk. j. biol. 43(1): 58-69. bbs. 2022. yearbook of agricultural statistics, bangladesh bureau of statistics (bbs), statistics and informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka bangladesh. bhalla, p.r., t.w. whitaker and p.s. sabharwal. 1973. effect of water soluble tobacco smoke extracts from filter and non-filter cigarettes on seed germination of onion and tomato. environ. pollut. 5: 231-236. cabral, j.r., p.s.l. freitas, a. bertonha, and a.s. muniz. 2010. effects of wastewater from a cassava industry on soil chemistry and crop yield of lopsided oats (avena strigosa schreb.). bra. arch. biol. tech. 53: 19-26. chidambara, r.c.b. and l.q. han. 2004. advanced oxidation processes for wastewater treatment: optimization of uv/h2o2 process through a statistical technique. chem. eng. sci. 60: 53055311. 136 pramanik et al. copeland, l.o. 1976. principles of seed science and technology, burgess publication company, minneapolis, minnesota, 164165 pp. dash, a.k. 2012. impact of domestic waste water on seed germination and physiological parameters of rice and wheat. int. j. res. rev. appl. sci. 12(2): 280-286. guo, x. t. li, k. tang and r.h. liu. 2012. effect of germination on phytochemical profiles and antioxidant activity of mung bean sprouts (vigna radiata). j. agric. food. chem. 60: 11050 – 11055. hossain, m. s., m. j. islam, b. c. sarker, s. k. pramanik, r. khatun and m. n. zahan. 2018. suitability assessment of wastewater of three tobacco industries for irrigation and germination of some vegetable seeds. int. j. sci. busi. 2(3): 459-479. huma, z., s. naveed, a. rashid, a. ullah and i. khatta. 2012. effects of domestic and industrial waste water on germination and seedling growth of some plants. curr. opin. agric. 1(1): 27-30. islam, m.r., g.k.m.m rahman, m.a. saleque and m.j. uddin. 2017. effect of industrial effluents on seed germination and seedling growth of rice. dhaka univ. j. biol. sci. 26(1): 59-68. jianhua, y.i., j. zhihong, l. qi, l.v. huzhen and s. hong. 2012. allelopathic effects of decaying tobacco leaves on tobacco seedlings. allelopathic j. 29(1): 5162. krishnasamy, v. and d.v. seshu. 1990. germination after accelerated aging and associated characters in rice varieties. seed sci. tech. 18: 353-359. mehta, a. and n. bharadwaj. 2012. phytotoxic effect of industrial effluent on seed germination and seedling growth of vigna radiata and cicer arietinum. global j. biosci. biotech. 1(1): 1-5. messrouk, h., m.m. hadj, y. touil and a. amrane. 2014. physico-chemical characterization of industrial effluents from the town of ouargla (south east algeria). energy procedia 50: 255262. mojiri, a., h.a. aziz, s.q. aziz, a. gholami and m. aboutorab. 2013. impact of urban wastewater on soil properties and lepidiumsativum in an arid region. int. j. sci. res. environ. sci. 1(1): 1-9. niroula, b. 2003. comparative effects of industrial effluents and submetropolian sewage of biratnagar on germination and seedling growth of rice and blackgram. our nature. 1: 10–14. patil, v.n., r.s patil, s. yadav, a. mulla, s. jadhav and h.v. patil. 2020. phytotoxic effect of industrial effluent on germination of triticum aestivum following in-vitro exposure. int. j. innov. res. sci. eng. tech. 9(4): 1512-1515. pokharel, b., b. niroula and s.k. rai. 2000. study of toxicity of some industrial effluents on root growth of allium cepa. in: third national conference on science and technology. proceedings (volume ii). royal nepal academy of science and technology (ronast), pp. 1151-1154. pramanik, s.k. 2021. impact assessment of tobacco industry wastewater on germination and early seedling growth of mung bean [vigna radiata (l.) r. wilczek]. the agriculturists 19(1&2): 86-94. pramanik, s.k. and s. sikder. 2020. germination and seedling leaf chlorophyll content of wheat under industrial wastewater condition. the agriculturists. 18(1): 10-17. ramana, s., a.k. biswas, s. kundu, j.k. saha and r.b.r. yadav. 2002. effect of distillery effluent on seed germination in some vegetable crops. biorec. tech. 82: 273-275. saravanamoorthy, m.d. and b.d. ranjitha-kumari. 2007. effect of textile waste water on morphophysiology and yield on two varieties of peanut (arachis hypogea l.). j. agril. tech. 3: 335343. tobacco industry wastewater impacts on germination and growth of mungbean 137 sharma, r. k., m. agrawal, and f.m. marshall. 2004. effects of waste water irrigation on heavy metal accumulation in soil and plants. paper presented at a national seminar, bangalore university, bangalore, pp. 7-8. sponza, d.t. 2002. toxicity studies in a tobacco industry biological treatment plant. water, air soil pollution. 134: 137-164. suseelamma, m. and r.r. venkataraju. 1994. effect of diger amuricata (l.) mart. extracts on the germination and seedling growth of groundnut. allelopathy j. 1: 53-57. thamizhiniyan, p., p.v. sivakumar, m. lenin and m. sivaraman. 2009. sugar mill effluent toxicity in crop plants. j. phyto. 1: 68-74. thomas, m., j. robertson, s. fukai and m.b. peoples. 2004. the effect of timing and severity of water deficit on growth development, yield accumulation and nitrogen fixation of mungbean. field crops res. 86: 67-80. undp (united nations development program) 2016.the groundwater resources and its availability for development.master plan organization, ministry of irrigation, water development and flood control, government of the people's republic of bangladesh.technical report no. 5, pp. 4-46. bangladesh agron. j. 2024, 27(1): 9-18 efficacy of moringa leaf extract hormesis as natural biostimulant on yield and bioactive compounds of lettuce s.k. pramanik1*, d. saha1, s. mou1, s. ahammed1, t. siddiquea1, b.s. bandhan2, l. roy1 and r. hasan1 1department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh 2department of chemistry, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh *corresponding author, email: pramaniksk100@gmail.com (received: 2 december 2024, accepted: 31 march 2025) keywords: lettuce, biostimulant, spad, phenol, flavonoid, vitamin c abstract this study was conducted to assess the effectiveness of moringa (moringa oleifera lam.) leaf extract (mle) as a natural biostimulant on yield and bioactive compounds of lettuce. the trial was conducted during november 2023 to february 2024 with lettuce var. bari lettuce-1. twenty plastic pots following complete randomized design with four replications was followed. four concentrations (3%, 4%, 5% and 6%) of mle was foliar sprayed into lettuce where a control treatment (tap water) was also considered. leaf number, leaf length, fresh and dry weight of leaves, spad value, total chlorophyll, total phenol, flavonoid and vitamin c were assessed. correlation and regression analysis among the traits were also carried out. the results show that there was significant improvement in yield traits and bioactive compounds of lettuce except vitamin c due to foliar spray of mle, where 6% mle was found to maximize the value of the all studied traits of lettuce. plants treated with 6% mle provided maximum improvement by 25.01% in leaf number, 14.11% in leaf length, 20.61% in leaf fresh weight, 36.10% in leaf dry weight, 13.13% in spad value, 53.72% in total chlorophyll, 34.17% in total phenol and 19.29% in flavonoid compared to that of control. correlation analysis among leaf traits and bioactive compounds showed positive connection with each other. similarly, regression analysis among bioactive compounds exhibited positive correlation regression among the traits. therefore, mle could play a significant role as safe and natural biostimulant in improving yield and quality of lettuce through improving the vegetative and bioactive traits of lettuce leaf. introduction lettuce (lactuca sativa l.), a member of the asteraceae family, is cultivated worldwide and one of the most consumed rosette leafy vegetables in the raw form for its taste and high nutritive value. it is considered as one of the most important salad vegetables and an excellent source of vitamins, iron, folate, caffeic acid, carotenoids, and other antioxidants (sonmez et al., 2017; malejane et al., 2018). lettuce is a soil nutrient-depleted vegetable which produces a very shallow root system and requires adequate levels of fertilizer during its growing season (thorup-kristensen, 2001). excessive fertilization of the lettuce field may cause many issues to the environment as water quality throughout leaching and runoff, eutrophication, greenhouse effect and acid rain (heckman, 2007; wang et al., 2013) and harmful effects on human health (ikemoto et al., 2002; liu et al., 2014). the rising awareness of consumers on the importance of consuming sustainable, safe, and healthy foods could be met by improving the quality of leafy vegetables with the use of natural biostimulants (corbo et al., 2015). safe and environmentally friendly natural products, such as natural biostimulants have essential role in sustainable agriculture 10 pramanik et al. through improving plant productivity and food quality while reducing environmental pollution (shalaby, 2024). biostimulants are the products derived from biological materials that improve plant productivity including yield, quality and production efficiency due to the presence of plant growth regulators, essential nutrients and plant protective compounds (yakhin et al., 2017, ho). among natural biostimulants, moringa (moringa oleifera lam.) leaf extract (mle) has attained massive attention due to its notable effect on plant productivity (merwad, 2018; zulfiqar et al., 2020). moringa (moringa oleifera lam.) leaf extract is a recently concerned plant extract that is applied to the plants as an environmentally friendly and safe biostimulant, since it contains many beneficial bioactive compounds, macro and micronutrients, minerals, plant hormones, vital amino acids and vitamins (sohaimy et al., 2015; yaseen and há jos, 2021). moringa (moringa oleifera lam.) leaf extract is also considered as an alternative to inorganic fertilizer (saini et al., 2016). the benefits of mle as a growth enhancer in improving yield and quality has been found in lettuce (yaseen and há jos, 2021) and many other crops. no research information is available on the influence of mle in improving the vegetative yield and quality of bangladeshi lettuce cultivars. therefore, the study was aimed to assess the feasibility of applying mle to improve leaf yield and bioactive compounds of bangladeshi lettuce variety, bari lettuce-1. materials and methods location, duration and growing conditions a pot experiment was conducted at department of crop physiology and ecology, hajee mohammad danesh science and technology university (hstu), dinajpur during november 15, 2023 to february 15, 2024. the experimental area is located under the agroecological zone-1 of old himalayan piedmont plain with an elevation of 37.58 m above the sea level. the experimental area belongs to the subtropical climate characterized by rainfall during the month of last april to october and scanty rainfall in the rest of the year. the average temperature and humidity during the lettuce growing season is presented in fig. 1. twenty plastic pots (20 cm diameter and 25 cm height) were filled with equal amount (10 kg pot−1) of a combined medium of soil and compost (weight ratio = 3:1). the soil was characterized by sandy loam texture with ph 5.50, organic carbon 0.24%, organic matter 0.413%, salinity 0.37 ds m−1, total n 0.021%, available p 29.22 μg g−1 and exchangeable k 0.117 meq 100 g−1. inorganic fertilizers were applied on the basis of mass of soil per hectare area @ 200 kg urea, 75 kg tsp and 75 kg mop as per recommendation of bangladesh agricultural research institute (azad et al., 2019). fig. 1. mean temperature and humidity during the growing season of lettuce efficacy of moringa leaf extract hormesis on yield and bioactive compounds of lettuce 11 raising of plant materials and transplanting in the experimental pots seeds of bari lettuce-1 were sown in seedbed on november 15, 2023. after 25 days of the seed sowing, 3 seedlings were transplanted to each experimental pot and light irrigation was given immediately after transplanting and continued up to the seedling’s establishment and development in the pots. when the seedlings attained good development and hard enough then one healthy seedling was selected to remain in each pot and others were thinned out. necessary measures were taken to protect the crop from various insect-pest and diseases during the growing period of the crop when and as necessary. for better growth and development of the plants, irrigation was provided when and as required. experimental design and treatments the single factor experiment was performed using completely randomized design and replicated quarce. four concentrations of mle (3, 4, 5 and 6%) were sprayed on lettuce plants as foliar treatment along with a control treatment (normal tap water). preparation and application of moringa (moringa oleifera lam.) leaf extract moringa (moringa oleifera lam.) leaf extract was prepared by extraction of fresh young leaves obtained from mature moringa trees. first, the leaves were collected then washed and placed in a refrigerator at 4°c for 24 h as described by yaseen and takacs-hajos (2022). the stored leaves were grinded with the amount of 100 ml water kg−1 fresh material using a kitchen blender, thereafter the mixture was squeezed and passed through a locally fabricated extraction machine and filtered twice using whatman no. 1 filter paper based on the method by foidl et al. (2001). the filtrate was placed in 8000 × g centrifuge for 15 min and supernatant was collected. the collected supernatant was considered as 100% mle and saved as a stock extract for preparing desirable concentration of mle (yasmeen et al., 2013). the extract was subject to keep in the refrigerator at 4℃ till the plants ready to be foliar sprayed. the required concentration of 3, 4, 5 and 6% mle were prepared for the foliar spray from stock extract and mixed with 0.1% (v/v) surfactant (tween 20) for optimal penetration. two weeks after transplanting, the plants were foliar sprayed with respective concentrations of mle by a hand sprayer at every 10 days intervals where the control plants were sprayed with water only. harvesting and data collection all lettuce plants were harvested at 50 days after transplanting and data were collected on foliage yield (leaf number plant−1, leaf length, fresh weight and dry weight of leaves plant−1) and bioactive compounds (spad value, total chlorophyll, total phenol, flavonoid and vitamin c content of leaf). spad value of leaf was recorded just before harvesting the plants with a hand held spad meter (model: spad-502 plus, konica minolta, inc.). fig. 2. standard calibration curve of gallic acid (a) and quercetin (b) for determination of total phenol and flavonoid, respectively. a b y = 0.0104x + 0.0469 r2 = 0.998 0 0.1 0.2 0.3 0.4 0.5 0 20 40 60a b so rb a n ce a t 7 6 5 n m concentration of gallic acid (ppm) y = 0.0019x 0.0013 r2 = 0.995 0 0.05 0.1 0.15 0.2 0 50 100 150 a b so rb a n ce a t 4 1 5 n m concentration of quercetin (ppm) 12 pramanik et al. total chlorophyll and vitamin c were measured on fresh weight basis but total phenol and flavonoid were determined on dry weight basis after harvesting the leaves. total chlorophyll was estimated according to witham et al. (1986) using the formula: total chlorophyll (mg g−1 fw) = [20.2 (d645) + 8.02 (d663)] × [v/ (1000 × w)], where, v = volume of 80% aqueous acetone (ml), w = weight of fresh leaf (g), d645 = absorbance at 645 nm wavelength and d663 = absorbance at 663 nm wavelength. phenolic content of the dry extract of leaf was measured by the modified folin-ciocalteu’s method as described by zilani et al. (2016). flavonoid content of dry extract of leaf was estimated using aluminium chloride colorimetric assay as described by mahmud et al. (2017). vitamin c content was determined by redox titration using iodine solution following the method described by ciancaglini et al. (2001). statistical analyses the recorded data were analyzed by partitioning the total variance with the help of software package “statistix 10” program and the treatment means were compared by using tukey’s test at 5% level of probability. results and discussion leaf traits of lettuce the result showed that leaf traits of lettuce plant (leaf number plant−1, leaf length, fresh weight and dry weight of leaves plant−1) were significantly affected due to foliar application of different concentrations of mle (table 1). table 1. effect of foliar application of mle on leaf traits of lettuce treatments leaf number plant−1 leaf length (cm) fresh weight of leaves plant−1 (g) dry weight of leaves plant−1 (g) control 16.95 c 24.38 b 207.03 c 15.54 b 3% mle 18.96 bc (+11.86) 24.45 a (+0.29) 215.49 bc (+4.09) 15.64 b (+0.64) 4% mle 20.85 ab (+23.01) 25.14 a (+3.12) 236.20 ab (+14.09) 16.34 b (+5.15) 5% mle 20.96 ab (+23.66) 26.10 a (+7.05) 239.30 ab (+15.59) 20.24 a (+30.24) 6% mle 21.19 a (+25.01) 27.82 a (+14.11) 249.71 a (+20.61) 21.15 a (+36.10) lsd (0.05) ** * ** ** cv (%) 4.02 5.01 4.01 5.05 cd 2.1382 3.3958 24.734 2.4135 in a column, means having similar letter(s) did not differ significantly at p  5% level by tukey. ** and * indicate significant at 1% and 5% level of probability, respectively. values in parenthesis indicate % improvement over control in respective treatment. the minimum values of the leaf traits of lettuce were recorded under control condition, whereas the maximum values of the traits were measured under 6% mle treated condition. results showed that exogenously applied mle meaningfully improved all the leaf traits studied as compared to control (normal water) at different extends. the degrees of improvement in leaf number plant−1 of lettuce were 11.8, 23.01, 23.66 and 25.01% for 3, 4, 5 and 6% mle treatments, respectively. an increase of 0.29, 3.12, 7.05, and 14.11% were observed in leaf length of lettuce due to application of 3, 4, 5 and 6% mle, correspondingly when compared to control. in terms of fresh mass of leaves plant−1, statistically similar enhancement (14.09, 15.59 and 20.61%) was observed in 4, 5 and 6% mle treated lettuce, respectively, whereas 4.09% increment under 3% mle as compared to that of control. the dry weight of leaves plant−1 of efficacy of moringa leaf extract hormesis on yield and bioactive compounds of lettuce 13 lettuce also showed substantial progression under mle application with the increment of 0.64, 5.15, 30.24 and 36.10% for respective mle concentrations (3, 4, 5 and 6% mle) than that of non-treated control condition. overall results clarified that the highest magnitude of enhancement across all the leaf traits was observed under 6% mle treatment, indicating that this concentration provided the most significant improvement regarding leaf traits compared to the other concentrations of mle applied. it is noticeable that foliar application of mle had significant positive effect on forecited vegetative growth characters of lettuce plant. foliar application of mle significantly increased the leaf number and leaf length of each leaf of lettuce which consequently resulted in increased fresh and dry mass plant−1 as compared to control (normal tap water). the enhancement of lettuce leaf traits using mle may be due to as moringa leaf is a rich source of amino acids, potassium, calcium, iron, vitamin e, ascorbates, phenolic compounds and growth regulating hormones like zeatin (jiang and asami, 2018) that reflected on an increase in growth characters of plants. the presence of phytohormones (auxin, ga3 and especially cytokinin) (latif and mohamed, 2016) in biostimulant like mle influence the physiological processes in plants (rodrigues et al., 2020) where cytokinin plays a vital role in increasing sink capacity (zwack and rashotte, 2013). this findings are in a line with the findings of chanthanousone et al. (2022) who had been reported that the supplementation of mle @ 200 mg l−1 enhanced the fresh mass and quality of lettuce leaves. similar responses of lettuce plant to mle were also observed by admane et al. (2023) on hydroponic lettuce and elbagory (2018) on head lettuce. bioactive compounds of lettuce leaf the analysis of variance of collected data on bioactive compounds of lettuce leaf indicates that, foliar application of mle significantly influenced the spad value (p ≤ 0.05), total chlorophyll (p ≤ 0.01), total phenol (p ≤ 0.01) and flavonoid content (p ≤ 0.05) of lettuce leaf except vitamin-c content of leaf (table 2). table 2. effect of foliar application of mle on spad value and bioactive compounds of lettuce leaf treatments spad value total chlorophyll (mg g−1 fw) total phenol (mg gae g−1 dw) flavonoid (mg qe g−1 dw) vitamin c (mg g−1 fw) control 42.12 b 2.55 c 5.18 d 6.48 b 0.0347 3% mle 43.59 ab (+3.49) 2.81 bc (+10.20) 5.52 cd (+6.56) 7.10 ab (+9.57) 0.0349 (+0.58) 4% mle 43.76 ab (+3.89) 3.12 b (+22.35) 6.12 bc (+18.15) 7.35 a (+13.43) 0.0357 (+2.88) 5% mle 45.43 ab (+7.86) 3.78 a (+48.26) 6.53 ab (+26.06) 7.49 a (+15.59) 0.0351 (+1.15) 6% mle 47.65 a (+13.13) 3.92 a (+53.72) 6.95 a (+34.17) 7.73 a (+19.29) 0.0363 (+4.61) lsd (0.05) * ** ** * ns cv (%) 4.01 5.14 5.08 3.99 4.98 cd 4.7908 0.4468 0.8270 0.7753 0.4731 in a column, means having similar letter(s) did not differ significantly at p 5% level by tukey. ** and * indicate significant at 1% and 5% level of probability, respectively. ns indicates not significant at 5% level of probability. values in parenthesis indicate % improvement over control in respective treatment. the findings revealed that, foliar application of mle notably increased the bioactive compounds of lettuce leaf as compared to control condition but the degrees of increment were different for different concentrations of mle. though, there was no significant variation among the vitamin c content of lettuce leaf under different treatments. the degrees of augmentations in these bioactive traits were maximum with the 6% mle application, followed by the 5, 4, and 3% mle treatments, respectively. among the treatments, the 3% mle treatment improved the bioactive compounds of lettuce leaf by 3.49% in spad value, 10.20% in total chlorophyll content, 6.56% in total phenol content, 9.57% in flavonoid content and 0.58% in vitamin c 14 pramanik et al. content. an increasing level of 3.89% in spad value, 22.35% in total chlorophyll content, 18.15% in total phenol content, 13.43% in flavonoid content, and 2.88% in vitamin c content of lettuce leaf was observed when the lettuce plant was treated with 4% mle. under the treatment of 5% mle, 7.86, 48.26, 26.06, 15.59 and 1.15% improvement were recorded in spad value, total chlorophyll content, total phenol content, flavonoid content and vitamin c content of lettuce leaf, respectively. the 6% mle caused the uppermost augmentations with the increasing level of 13.13% in spad value, 53.72% in total chlorophyll content, 34.17% in total phenol content, 19.29% in flavonoid content and 4.61% in vitamin c content, making it the most effective treatment for enhancing these attributes as compared to other treatments. as expected, the mle application provides higher photosynthetic pigments that contribute to the enhancement of greenness (spad index) and chlorophyll content of leaf (khan et al. 2022). this ability to increase pigment content is in line with other reports on plant-based biostimulants, whose application may lead to the up-regulation of nitrogen and carbon metabolism by enhancing n uptake efficiency and limiting chlorophyll degradation as well as leaf senescence (colla et al., 2017). elzaawely et al. (2017) further mentions that the quality enhancement in plants treated with mle is related to the hormone concentration in moringa leaves, particularly gibberellins (ga7). under a glasshouse experiment, increments in polyphenols of different lettuce cultivars were found in plants treated with 6% mle (yaseen and takacs-hajos, 2022). moringa (moringa oleifera lam.) leaf extract application at a concentration of 20% displayed the maximum phenolic and flavonoid content in the stevia leaf (sardar et al., 2021) that indicates the positive responses of mle as the present study. the increment in vitamin c of lettuce leaf due to 6% foliar mle was also reported by yaseen and takacs-hajos (2022). correlation analysis of the leaf traits and bioactive compounds of lettuce correlation analysis among different leaf traits and bioactive compounds of lettuce presented in table 3 reveals that all the traits showed significant positive correlation with each other except the relation of vitamin c with leaf dry weight plant−1 and total chlorophyll content. table 3. correlations (pearson) among leaf traits and bioactive compounds of lettuce lnp ll fwlp dwlp spad tccl tpcl fcl vit c lnp 1.0000 *** ll 0.7640 *** 1.0000 *** fwlp 0.9574 *** 0.8417 *** 1.0000 *** dwlp 0.7512 ** 0.7789 *** 0.8625 *** 1.0000 *** spad 0.8123 *** 0.9078 *** 0.9042 *** 0.8839 *** 1.0000 *** tccl 0.8722 *** 0.7633 *** 0.9284 *** 0.9717 *** 0.8741 *** 1.0000 *** tpcl 0.9275 *** 0.8219 *** 0.9857 *** 0.9298 *** 0.9215 *** 0.9745 *** 1.0000 *** fcl 0.9687 *** 0.8349 *** 0.9600 *** 0.8088 *** 0.9197 *** 0.8910 *** 0.9477 *** 1.0000 *** vit c 0.6081 * 0.8919* ** 0.6911* * 0.4959 ns 0.8044* ** 0.4829n s 0.6249 * 0.7082 ** 1.0000 *** lnp = leaf number plant−1, fwlp = fresh weight of leaves plant−1, dwlp = dry weight of leaves plant−1, spad = spad value of leaf, tccl = total chlorophyll content of leaf, tpcl = total phenol content of leaf, fcl = flavonoid content of leaf, vit c= vitamin c content of leaf. *, ** and *** indicate correlation is significant at the 0.05, 0.01 and 0.001 level of probability (1-tailed), respectively. ns indicates correlation is not significant at the 0.05 level of probability. efficacy of moringa leaf extract hormesis on yield and bioactive compounds of lettuce 15 the strongest significant positive correlation was observed in fwlp-tpcl (r = 0.9857***) followed by tccl-tpcl (r = 0.9745***), dwlp-tccl (r = 0.9717***), lnp-fcl (r = 0.9687***), fwlp-fcl (r = 0.9600***), lnp-fwlp (r = 0.9574***), tpcl-fcl (r = 0.9477***), dwlp-tpcl (r = 0.9298***), fwlp-tccl (r = 0.9284***), lnp-tpcl (r = 0.9275***), spadtpcl (r = 0.9215***), spad-fcl (r = 0.9197***), ll-spad (r = 0.9078***) and fwlp-spad (r = 0.9042***). moderate significant and positive connection was discovered in ll-vit c (r = 0.8919***), tccl-fcl (r = 0.8910***), dwlp-spad (r = 0.8839***), spad-tccl (r = 0.8741***), lnp-tccl (r = 0.8722***), fwlp-dwlp (r = 0.8625***), ll-fwlp (r = 0.8417***), ll-fcl (r = 0.8349***), ll-tpcl (r = 0.8219***), lnp-spad (r = 0.8123***), dwlp-fcl (r = 0.8088***) and spad-vit c (r = 0.8044***). comparatively weak but significant positive association was found in ll-dwlp (r = 0.7789***), lnp-ll (r = 0.7640***), ll-tccl (r = 0.7633***) and lnp-dwlp (r = 0.7512**). among the correlations, comparatively weaker but positively significant connection was detected in fcl-vit c (r = 0.7082**) and fwlp-vit c (r = 0.6911**) and the weakest but significant positive correlation was found in lnp-vit c (r = 0.6081*) closely followed by tpcl-vit c (r = 0.6249*), whereas the non-significant but positive correlation was observed in dwlp-vit c (r = 0.4959ns) and tccl-vit c (r = 0.4829ns). regression analysis of the bioactive compounds and spad value of lettuce regression analysis results of the bioactive compounds of lettuce in fig. 3 reveals that, vitamin c had positive correlation regression equation with phenol content (r2 = 0.6861) and flavonoid content (r2 = 0.6383) of lettuce leaf. even so, positive correlation regression equation was found between total chlorophyll content and spad value as well as between phenol content and flavonoid content of lettuce leaf at r2 = 0.8917 and r2 = 0.8967, respectively. fig. 3. regression equation results of the studied bioactive compounds and spad value of lettuce y = 0.2674x 8.6654 r2 = 0.8917 0 1 2 3 4 5 40 42 44 46 48 c h l (m g g − 1 f w ) spad y = 1.4314x 4.2892 r2 = 0.8967 0 2 4 6 8 6 6.5 7 7.5 8 p h e n o l (m g g a e g − 1 d w ) flavonoid (mg qe g−1 dw) y = 0.0751x + 3.0789 r2= 0.6861 3.45 3.5 3.55 3.6 3.65 0 5 10v it c ( m g 1 0 0 g − 1 f w ) phenol (mg gae g−1 dw) y = 0.1095x + 2.7423 r2 = 0.6383 3.4 3.45 3.5 3.55 3.6 3.65 6 6.5 7 7.5 8v it c ( m g 1 0 0 g − 1 f w ) flavonoid (mg qe g−1 dw) 16 pramanik et al. conclusion moringa (moringa oleifera lam.) leaf extract as natural biostimulant improved yield traits and certain bioactive components of lettuce leaf. therefore, mle can be the reliable source of safe and natural biostimulant for stimulating yield and quality of lettuce. however, further studies will be effective to reach a conclusion about the efficacy as well as optimum concentration of mle for improving productivity and quality of lettuce, ensuring its practical application in sustainable crop management. references admane, n., g. cavallo, c. hadjila, m.m. cavalluzzi, n.p. rotondo, a. salerno, j. cannillo, g. difonzo, f. caponio and ippolito. 2023. biostimulant formulations and moringa oleifera extracts to improve yield, quality, and storability of hydroponic lettuce. mol. 28: 373. azad, a.k., m.a. ohab, m.g. saha, j. nechha, m.l. rahman, m.h.h. rahman and m. al-amin. 2019. krishi projukti hatboi (handbook on agro-technology). edited, 8th edition, bangladesh agricultural research institute, gazipur-1701, bangladesh. pp. 170. chanthanousone, h., t.t. phan, c.q. nguyen, t.d.t. nguyen, l.t. dang, n.t.h. ho, b.q.l. nguyen and h.t.h. truong. 2022. influence of foliar application with moringa oleifera residue fertilizer on growth, and yield quality of leafy vegetables. j. expt. biol. agril sci. 10(6): 1453-1461. ciancaglini, p., h.l. santos, k.r.p. daghastanli and g. thedei. 2001. using a classical method of vitamin c quantification as a tool for discussion of its role in the body. biochem. and mol. biol. edu. 29: 110-114. colla, g., m. cardarelli, p. bonini and y. rouphael. 2017. foliar applications of protein hydrolysate, plant and seaweed extracts increase yield but differentially modulate fruit quality of greenhouse tomato. hortic. sci. 52: 1214 1220. corbo, m., d. campaniello, b. speranza, a. bevilacqua and m. sinigaglia. 2015. non-conventional tools to preserve and prolong the quality of minimally-processed fruits and vegetables. coatings. 5: 931961. elbagory, m. 2018. effectiveness of organic fertigation and moringa leaf extract spray as an alternative to chemical fertigation for improving yield and quality of lettuce under soilless condition. env. biodiversity soil sec. 2: 175-182. elzaawely, a.a., m.e. ahmed, h.f. maswad and t.d. xuan. 2017. enhancing growth, yield, biochemical, and hormonal contents of snap bean (phaseolus vulgaris l.) sprayed with moringa leaf extract. arch. agron. soil sci. 63(5): 687 699. fao. 2021. food and agriculture organization. data (http://www.fao.org/faostat/en/#data/ qc, accessed on 19 september 2021. foidl, n, h.p.s. makkar and k. becker. 2001. the potential of moringa oleifera for agricultural and industrial uses in: proceedings of the international workshop “what development potential for moringa products”, dar-es-salaam, tanzania. 47-67. heckman, j.r. 2007. sweet corn nutrient uptake and removal. horttechnology. 17: 82-86. hoque, t.s., i. jahan, g. ferdous and m.a. abedin. 2020a. foliar application of moringa leaf extract as a bio-stimulant on growth, yield and nutritional quality of brinjal. j. agric. food env. 1(4): 94-99. hoque, t.s., md. s. rana, s.a. zahan, i. jahan and m.a. abedin. 2020b. moringa leaf extract as a biostimulant on growth, yield and nutritional improvement in cabbage. asian j. med. biol. res. 6(2): 196-203. ikemoto, y, m. teraguchi and y. kobayashi. 2002. plasma levels of nitrate in congenital heart disease: comparison with healthy children. ped. cardiology. 23 (2): 132-136. jiang, k. and t. asami. 2018. chemical regulators of plant hormones and their applications in basic research and agriculture. biosci., biotech. and biochem. 82: 1265-1300. khan, s., d. ibrar, s. bashir, n. rashid, v. hasnain, m. nawaz, a.a. al-ghamdi, m.s. elshikh, h. dvoˇrá ˇcková and j. dvoˇrá ˇcek. 2022. application of moringa leaf extract as a seed priming agent enhances growth and physiological attributes of rice seedlings cultivated under water deficit regime. plants. 11: 261. kim, m.j., y. moon, j.c. tou, b. mou and n.l. waterland. 2016. nutritional value, bioactive compounds and health benefits of lettuce (lactuca sativa l.). j. food comp. anal. 49: 19-34. efficacy of moringa leaf extract hormesis on yield and bioactive compounds of lettuce 17 latif, h.h. and h.i. mohamed. 2016. exogenous applications of moringa leaf extract effect on retrotransposon, ultrastructural and biochemical contents of common bean plants under environmental stresses. south african j. bot. 106: 221-231. liu, c.w., y. sung, b.c. chen and h.y. lai. 2014. effects of nitrogen fertilizers on the growth and nitrate content of lettuce (lactuca sativa l.). int. j. env. health res. 11: 4427-4440. mahmud, i., m.n. zilani, n.n. biswas and b. bokshi. 2017. bioactivities of bruguiera gymnorrhiza and profiling of its bioactive polyphenols by hplc-dad. clinical phytoscience. 3(1): 1-1. malejane, d.n.p., p. tinyani, y. soundy, sultanbawa and d. sivakumar. 2018. deficit irrigation improves phenolic content and antioxidant activity in leafy lettuce varieties. food sci. nutr. 6: 334-341. mampholo, b.m., m.m. maboko, p. soundy and d. sivakumar. 2016. phytochemicals and overall quality of leafy lettuce (lactuca sativa l.) varieties grown in closed hydroponic system. j. food quality. 39(6): 805-815. merwad, a.r.m. 2018. using moringa oleifera extract as biostimulant enhancing the growth, yield and nutrients accumulation of pea plants. j. plant nutr. 41: 425-431. nasir, m., a.s. khan, s.a. basra and a.u. malik. 2016. foliar application of moringa leaf extract, potassium and zinc influence yield and fruit quality of ‘kinnow’ mandarin. int. j. hortic. sci. 210: 227-235. rodrigues, m., j.l.c. baptistella, d.c. horz, l.m. bortolato. and p. mazzafera. 2020. organic plant biostimulants and fruit quality-a review. agron. 10: 988. romani, a., p. pinelli, c. galardi, g. sani, a. cimato and d. heimler. 2002. polyphenols in greenhouse and open-air-grown lettuce. food chem. 79 (3): 337-342. saini, r.k., i. sivanesan and y.s. keum. 2016. phytochemicals of moringa oleifera: a review of their nutritional, therapeutic and industrial significance. biotech. 6: 1-14. sardar, h., a. nisar, m.a. anjum, s. naz, s. ejaz, s. ali, m.s. javed and r. ahmad. 2021. foliar spray of moringa leaf extract improves growth and concentration of pigment, minerals and stevioside in stevia (stevia rebaudiana bertoni). ind. crops prod. 166: 113485. shalaby, o.a. 2024. moringa leaf extract increases tolerance to salt stress, promotes growth, increases yield, and reduces nitrate concentration in lettuce plants. sci. hortic. 325: 112654. sohaimy, s.a.e., g.m. hamad, s.e. mohamed, m.h. amar and r.r. al-hindi. 2015. biochemical and functional properties of moringa oleifera leaves and their potential as a functional food. glob. adv. res. j. agril sci. 4: 188-199. sonmez, i., h. kalkan, h. demir, r. kulcu, o. yaldiz and m. kaplan. 2017. mineral composition and quality parameters of greenhouse grown lettuce (lactuca sativa l.) depending on fertilization with agricultural waste composts. acta sci. pol-hortoru. 16: 85-95. thorup-kristensen, k. 2001. root growth and soil nitrogen depletion by onion, lettuce, early cabbage and carrot. acta hortic. 563: 201-206. wang, s.y. and h. gao. 2013. effect of chitosan-based edible coating on antioxidants, antioxidant enzyme system, and postharvest fruit quality of strawberries (fragaria x aranassa duch.). lwt-food sci. tech. 52(2): 71-79. witham, f.h., d.f. blaydes and r.m. devlin. 1986. exercise in plant physiology (2nd edition). prindle weber and schmidt publishers, boston, usa. 128-131. yakhin, o.k., a.a. lubyanov, i.a. yakhin and p.h. brown. 2017. biostimulants in plant science: a global perspective. front. plant sci. 7: 2049. yaseen, a. and m. takacs-hajos. 2020. effect of moringa leaf extract and set size on the bulb weight, diameter and yield of onions (allium cepa l.). acta agr. debr. 2: 127-131. yaseen, a.a. and m. takacs-hajos. 2022. evaluation of moringa (moringa oleifera lam.) leaf extract on bioactive compounds of lettuce (lactuca sativa l.) grown under glasshouse environment. j. king saud university-science. 34: 101916. yaseen, a.a. and m.t. há jos. 2021. the potential role of moringa leaf extract as bio-stimulant to improve some quality parameters of different lettuce (lactuca sativa l.) genotypes. sarhad j. agric. 37(4): 1107-1119. yasmeen, a., s.m.a. basra, m. farooq, h. rehman, h. hussain and h.r. athar. 2013. exogenous application of moringa leaf extract modulates the antioxidant enzyme system to improve wheat performance under saline conditions. plant growth reg. 69(3): 225-233. zilani, m.n., m.a. islam, s.s. khushi, j.a. shilpi, m.m. rahman and m.g. hossain. 2016. analgesic and antioxidant activities of colocasia fallax. ori. phar. expt. medicine. 16(2):131-7. 18 pramanik et al. zulfiqar, f., a. casadesú s, h. brockman and s. munné -bosch. 2020. an overview of plant-based natural biostimulants for sustainable horticulture with a particular focus on moringa leaf extracts. plant sci. j. 295: 110194. zwack, p. and a.m. rashotte. 2013. cytokinin inhibition of leaf senescence. plant sig. behav. 8: e24737. microsoft word 3. baj-468e bangladesh agron. j. 2024, 26(2): 16-26 evaluation of mung bean accessions for salt tolerance based on germination and seedling traits m.s.i. miajy1, m.n.t. etu1, b.s. bandhan2, a.k.m.m.b. chowdhury3, m.a. rahman3 and s.k. pramanik3* 1department of agronomy, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh 2department of chemistry, hajee mohammad danesh science and technology university, dinajpur-5200, bangladesh 3department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur5200, bangladesh *corresponding author, email: pramaniksk100@gmail.com (received: 26 september 2023, accepted: 29 march 2024) keywords: salinity stress, shoot and root growth, screening, green gram abstract ten mung bean accessions collected from bangladesh agricultural research institute were exposed to two salinity levels (control and 8 ds m−1) to observe the sensitivity of their germination and early seedling traits. the observations were recorded on germination percentage, rate of germination, coefficient of germination, shoot length, root length and seedling dry weight. the accessions, salinity levels and their interaction exhibited significant differences for all the traits. the mean performance of all the traits reduced under salt stress as compared to control. salt tolerant accessions showed less reduction in their germination and seedling traits under salinity than the other accessions tested. considering salt tolerance index (sti) based on seedling dry weight, the order of tolerance was bd6882 > bd-10022 > bd-10024 > bd-10026 > bd-10023 > bd-10027 > bd-6885 > bd-6887 > bd6884 > bd-6875. based on relative total dry weight (rtdw), three accessions viz. bd-6882, bd10022 and bd-10024 were identified as salt tolerant and other seven as moderately salt tolerant. the identified salt tolerant accessions could be a useful stock for further breeding programs to develop salt tolerant mung bean genotype of considerable economic value. introduction mung bean (vigna radiata l.) is the most important pulse crops of the world with great value for food, feed, fodder, fuel (straw), green manure and as a cover crop. it is also known as moong bean, mug dal or green gram, one of the popular pulse crops in bangladesh. being a short duration (about 60 days) crop, it is an ideal legume for catch cropping, intercropping, and relay cropping. mung bean has become the popular legumes in the tropic and sub-tropics for its rich nutritional components (thomas et al., 2004) and easily digestible protein source for human especially for poor people where meat is scarce (bangar et al., 2019). it is an excellent source of protein (24.5%) with high quality of lysine (460 mg g1) and tryptophan (60 mg g−1), fat (0.6%), fiber (0.9%) and ash (3.7%) (potter and hotchkiss, 1998). it also maintains soil fertility through biological nitrogen fixation in soil and thus plays a vital role in sustainable agriculture (kannaiyan, 1999). despite an economically important crop, the annual overall production (41000 mt) as well as average yield (0.93 mt ha−) of mung bean (bbs, 2022) is rather low in bangladesh. scarcity of quality seed of improved varieties, poor crop management practices as well as biotic and abiotic constraints are responsible for the low productivity of the crop (pratap et al., 2019). among different abiotic stresses, salinity is undoubtedly a major constraint for the production of mung bean as it is a salt sensitive crop (ashraf and rasul, 1988), where 50 mm nacl can cause up to 70% yield loss (saha et al., 2010). salinity increases the concentration of sodium and chloride ions which adversely affects the process of germination, seedling establishment, nutritional balance, plant growth and yield in almost all the cultivated crops by lowering the osmotic potential of water or by causing specific ionic toxicity, or both in the growing medium (zahedi et al., 2012; alom et al., 2016; kazal et 17 miajy et al. al., 2017). higher accumulation of salt causes oxidative stress ultimately leads to plant death as a consequence of growth arrest and metabolic damage (hasanuzzaman et al., 2012). it is predicted that 50% of the world's arable land will be salinized by 2050 (jamil et al., 2011; hasanuzzaman et al., 2013). in bangladesh, salinity has increased to 26% in the last 35 years (mahmuduzzaman et al., 2014) and the saline affected area is increasing continuously due to the effect of sea level rise, coastal subsidence, increased tidal effect and continuous reduction of river flow, particularly during dry period. it is a bitter truth that the agricultural land of the country is decreasing day by day and it is quite impossible to expand land horizontally. to increase the total food production of the country, using of marginal land like salt affected soil of the coastal areas for production purpose may be one of the effective strategies. therefore, screening and adaptation of salt tolerant crop varieties will be feasible and economical approach to increase the cropping intensities in the saline areas as well as to ensure food and nutritional security of the country like bangladesh. seed germination is largely affected by the toxicity of na+ and cl− ions, and the ability to withstand this toxicity vary from species to species and even from plant to plant (atak et al., 2006). keeping in view the yield losses due to low germination by salinity, it is very crucial to tackle salinity problem at germination level. in that case, to improve global crop productions, seed germination criteria could be used as quicker and early-stage screening approaches against salinity to identify salt-tolerant genotypes. current investigation was aimed to perform quick and effective screening of mung bean accessions at seed germination and early seedling stage against salinity stress for early selection of tolerant accessions. materials and methods experimental site and period the experiment was conducted at crop physiology and ecology laboratory, hajee mohammad danesh science and technology university, dinajpur, bangladesh in the month of march, 2023. experimental design and treatments ten mung bean accessions were evaluated under two growing conditions, control and nacl induced salt stress (8 ds m−1) following completely randomized design (crd) with three replications. saline solution was prepared by dissolving calculated amount of nacl (640 mg liter−1 water for 1 ds m−1) in tap water. normal tap water was used as control treatment. seed placement and data collection on germination and seedling traits twenty seeds of each accession were placed on filter paper soaked with treatment solution and tap water according to treatment in 11 cm diameter sterilized petri dish. before sowing, seeds were surface sterilized in 0.1% mercuric chloride solution for 30 seconds, and then were washed thoroughly with tap water followed by distilled water. each petri dish containing the seeds was irrigated with respective treatment solution and water throughout the experimental period. germination was counted at 24 hours interval and continued up to 6th day. a seed was considered germinated when plumule and radicle came out and was more than 2 mm long. the percentage of germination was counted on 6th day of placement of seeds. the rate of germination was calculated according to krishnasamy and seshu (1990) and co-efficient of germination was calculated using the formulae of copeland (1976). the length of shoot and root of seedling was recorded by centimeter scale on 8th day after seed placement. five seedlings from each petri dish were sampled for measuring shoot and root length. then the seedlings were dried separately at 70°°c for 72 hours in an electric oven, and weight was recorded with an electrical balance. the mean of length and dry weight were calculated for each treatment combination. calculation of stress tolerance index and relative total dry weight stress tolerance index (sti) was calculated according to goudarzi and pakniyat (2008) using the following formula evaluation of mung bean accessions for salt tolerance 18 stress tolerance index =୚ୟ୰୧ୟୠ୪ୣ ୫ୣୟୱ୳୰ୣୢ ୳୬ୢୣ୰ ୱ୲୰ୣୱୱ ୡ୭୬ୢ୧୲୧୭୬ ୚ୟ୰୧ୟୠ୪ୣ ୫ୣୟୱ୳୰ୣୢ ୳୬ୢୣ୰ ୬୭୰୫ୟ୪ ୡ୭୬ୢ୧୲୧୭୬ relative total dry weight (rtdw) was calculated according to ashraf and waheed (1990) and aziz et al. (2016) using the following formula relative total dry weight = ୈ୰୷ ୵ୣ୧୥୦୲ ୭୤ ୱୟ୪୲ ୲୰ୣୟ୲ୣୢ ୱୣୣୢ୪୧୬୥ ୈ୰୷ ୵ୣ୧୥୦୲ ୭୤ ୡ୭୬୲୰୭୪ ୱୣୣୢ୪୧୬୥ × 100 all the accessions were categorized as tolerant, moderately tolerant, susceptible and highly susceptible using a range of 0-9 scale following ashraf and waheed (1990). statistical analyses of data the experimental data were analyzed by partitioning the total variance using statistix 10 program and the means were compared by tukey’s test at 5% level of probability. results and discussion germination characteristics germination characteristics (percentage of germination, germination rate, and coefficient of germination) of mung bean were significantly varied due to individual effect of different mung bean accessions and salinity levels (table 1). different accessions showed statistically significant difference in germination percentage, germination rate and co-efficient of germination. the maximum germination percentage (94.74%) was recorded in bd-10026 which was nearly followed by bd-10022 (92.90%) and the minimum germination percentage (75.47%) was recorded in bd-6884 which was statistically similar with that of bd-6885 (75.62%) followed by bd-6887 (79.80%). other accessions showed moderate performance in respect to germination percentage (81.92% to 88.23%). the maximum and statistically similar germination rate was recorded in bd-10026 (93.23%) and bd-10022 (92.16%) followed by bd-6875 (85.76%) and bd-10024 (86.14%), whereas the minimum and statistically similar germination rate was observed in bd-6884 (72.98%) and bd-6885 (73.03%) followed by bd-6887 (77.07%). the maximum and statistically similar co-efficient of germination was found in bd-10022 (39.42), bd-10023 (39.18) and bd-10026 (38.97), while the minimum and statistically similar value of the trait was recorded in bd-6884 (31.70) and bd-6887 (31.86). salt stress significantly inhibited the germination capacity of mung bean accession which was represented by lower germination percentage (76.55%), germination rate (74.17%) and co-efficient of germination (33.58) compared to that of control (92.02, 91.18, and 38.15%, respectively). table 1. individual effect of mung bean accessions and salinity levels on germination characteristics of mung bean germination characteristics (mean ± se) treatments germination (%) germination rate (%) co-efficient of germination mung bean accessions bd-6875 86.35±1.6669 d 85.76±1.9789 b 35.59±1.1884 c bd-6882 81.92±2.5427 e 80.82±2.3243 d 36.79±0.9795 b bd-6884 75.47±3.0298 g 72.98±2.8756 f 31.70±0.7256 f bd-6885 75.62±5.5498 g 73.03±5.7099 f 34.80±0.7186 d bd-6887 79.80±6.8829 f 77.07±6.5951 e 31.86±2.1207 f bd-10022 92.90±2.6140 b 92.16±3.2064 a 39.42±1.4580 a bd-10023 85.31±6.4228 d 83.22±7.2784 c 39.18±2.242 a bd-10024 88.23±1.7811 c 86.14±1.7012 b 34.00±0.7063 e bd-10026 94.74±2.6509 a 93.23±3.1646 a 38.97±1.2992 a bd-10027 82.50±6.5039 e 82.37±7.3414 cd 36.36±1.5659 b level of significance ** ** ** critical value for comparison 1.1763 1.8889 0.6221 19 miajy et al. standard error for comparison 0.3504 0.5626 0.1853 salinity levels control (0 ds m-1) 92.02±1.2995 a 91.18±1.4566 a 38.15±0.7043 a salt stress (8 ds m-1) 76.55±1.9111 b 74.17±1.9176 b 33.58±0.5672 b level of significance ** ** ** critical value for comparison 0.3169 0.5088 0.1676 standard error for comparison 0.1567 0.2516 0.0829 cv (%) 0.72 1.18 0.89 in a column, values having same letter(s) did not differ significantly by tukey at p  5 %level. ** indicates significantly different at 1% level of probability. se indicates standard error. the interaction effect of different mung bean accessions and salinity levels was also significant on germination characteristics of mung bean (table 2). among the different treatment combinations, the maximum germination percentage (99.19%) was observed in bd-10023 and bd-10026 under control condition, whereas the minimum value of the trait was recorded in bd-6885 (63.63%) under salt stress. salt stress reduced the germination percentage by 2.24, 10.58, 14.84, 27.37, 31.73, 9.21, 28.00, 3.80, 8.97 and 29.26% in bd-6875, bd-6882, bd-6884, bd-6885, bd-6887, bd-10022, bd-10023, bd10024, bd-10026 and bd-10027, respectively. mung bean accession bd-10026 also showed highest germination rate (99.13%) under control which was statistically similar to that of bd-10023 (99.10%) and bd-10027 (98.43%) germinated under control condition. the lowest germination rate (60.63%) was recorded in bd-6885 under salt stress which was statistically at par with that of bd-6887 (62.66%) under salt stress. the degrees of reduction in germination rate due to salt stress were 5.85, 10.52, 14.38, 29.02, 31.50, 12.31, 32.06, 3.68, 11.91 and 32.52% in bd-6875, bd-6882, bd-6884, bd-6885, bd-6887, bd10022, bd-10023, bd-10024, bd-10026 and bd-10027, respectively. the maximum co-efficient of germination (43.96) was found in bd-10023 under control but bd-6887 showed the minimum value (27.33) of the trait under salt stress. the extents of lowering of co-efficient of germination due to salt stress were 11.89, 8.06, 6.94, 2.15, 24.88, 13.42, 21.75, 3.84, 11.63 and 15.83% in bd-6875, bd-6882, bd-6884, bd-6885, bd-6887, bd-10022, bd-10023, bd-10024, bd-10026 and bd-10027, respectively. development at the germination stage have been adopted a suitable growth stage for testing the stress tolerance in crop. in the present study salt stress considerably reduced the germination traits of mung bean accessions at different magnitudes as compared to control. table 2. interaction effect of mung bean accessions and salinity levels on germination characteristics of mung bean mung bean accessions salinity levels germination (%) % change over control rate of germination (%) % change over control co-efficient of germination % change over control bd-6875 control 87.33 ef -2.24 88.34 c -5.85 37.84 d -11.89 salt stress 85.37 g 83.17 f 33.34 g bd-6882 control 86.49 fg -10.58 85.30 d-f -10.52 38.33 d -8.06 salt stress 77.34 i 76.33 g 35.24 f bd-6884 control 81.52 h -14.84 78.63 g -14.38 32.84 g -6.94 salt stress 69.42 k 67.32 h 30.56 h bd-6885 control 87.61 ef -27.37 85.42 c-f -29.02 34.43 f -2.15 salt stress 63.63 l 60.63 i 35.17 f bd-6887 control 94.85 c -31.73 91.47 b -31.50 36.38 e -24.88 salt stress 64.75 l 62.66 i 27.33 i bd-10022 control 97.39 ab -9.21 98.20 a -12.31 42.26 b -13.42 salt stress 88.42 de 86.11 c-f 36.59 e evaluation of mung bean accessions for salt tolerance 20 bd-10023 control 99.19 a -28.00 99.10 a -32.06 43.96 a -21.75 salt stress 71.42 j 67.33 h 34.40 f bd-10024 control 89.94 d 3.80 87.75 cd -3.68 34.66 f -3.84 salt stress 86.52 fg 84.52 ef 33.33 g bd-10026 control 99.19 a -8.97 99.13 a -11.91 41.37 b -11.63 salt stress 90.29 d 87.32 cd 36.56 e bd-10027 control 96.64b c -29.26 98.43 a -32.52 39.48 c -15.83 salt stress 68.36 k 66.31 h 33.23 g level of significance ** ** ** critical value for comparison 1.8821 3.0221 0.9954 standard error for comparison 0.4955 0.7957 0.2621 cv (%) 0.72 1.18 0.89 in a column, values having same letter(s) did not differ significantly by tukey at p  5% level. ** indicates significantly different at 1% level of probability. se indicates standard error. differential degree of germination capacity of mung bean accessions under control and salt stress condition might be due to some genetic factors as well as heredity dissimilarities (win et al., 2011). it could be assumed that the nacl induced osmotic stress during the growth of germination stage inhibits the developmental traits and survival of mung bean as seedling survival of crop on saline soils may depend on tolerance to low osmotic potential (roundy, 1983). these adverse effects in germination might be due to reduction in water absorption by seeds due to high salinity which decreased osmotic pressure and create abnormalities in normal water uptake mechanisms (bayuelo-jiménez et al., 2002). decreasing germination rate and percentage of seed germination was due to excessive toxic cations and anions (na+ and cl−) produced in seeds at saline media (sanchez et al., 2014; sehrawat et al., 2013), where salt tolerant genotypes show relatively higher germination due to accelerated absorption of na+ (zhang et al., 2010). sehrawat et al. (2014) and kamrul et al. (2018) also observed salt stress caused reduction in germination traits of mung bean which corroborates with our present findings. germination and seedling characteristics were decreased with increasing salinity levels and widely reported in mung bean (swarnakar, 2016); in lentil, chickpea and faba bean (arslan et al., 2016) and in cowpea (haleem, 2015). these results are in consistent with the results of our study. early seedling traits early seedling traits (shoot length, root length and seedling dry weight) of mung bean were significantly influenced by individual effect of mung bean accessions and salinity levels (table 3). among the 10 mung bean accessions, the tallest shoot (10.89 cm) was observed in bd-6882 closely followed by that of bd-10024 (9.86 cm). mung bean accession bd-10026 produced the longest root (5.85 cm) which was statistically similar to root length of bd-6875 (5.49 cm). the maximum accumulation of dry matter in seedling (14.97 mg plant-1) was recorded in bd-10024 which was followed by bd-6884 (13.28 mg plant−1) and bd-10023 (13.08 mg plant−1). the shortest shoot (6.08 cm) and the minimum accumulation of dry matter in seedling (10.16 mg plant−1) were recorded in bd-6887, whereas the shortest root was found in bd-6884 (2.54 cm) which was statistically similar to that of bd-6885 (2.62 cm). table 3. individual effect of mung bean accessions and salinity levels on early seedling traits of mung bean treatments seedling traits (mean ± se) shoot length (cm) root length (cm) seedling dry weight (mg plant-1) mung bean accessions bd-6875 7.27±0.2693 ef 5.49±0.1429 ab 12.30±0.5977 d bd-6882 10.89±0.3398 a 4.81±0.1113 cd 10.56±0.2455 f bd-6884 7.95±0.3906 d 2.54±0.0714 f 13.28±0.5997 b bd-6885 7.03±0.2010 f 2.62±0.0825 f 11.17±0.3599 e 21 miajy et al. bd-6887 6.08±0.2010 g 3.57±0.1649 e 10.16±0.3663 g bd-10022 8.80±0.3429 c 5.08±0.2302 bc 12.02±0.3494 d bd-10023 8.94±0.2390 c 4.50±0.1625 d 13.08±0.4181bc bd-10024 9.86±0.4070 b 3.73±0.1607 e 14.97±0.4249 a bd-10026 8.20±0.2529 d 5.85±0.2760 a 12.00±0.3710 d bd-10027 7.46±0.3909 e 3.28±0.1793 e 12.91±0.4344 c level of significance ** ** ** critical value for comparison 0.3293 0.5716 0.3702 standard error for comparison 0.0981 0.1703 0.1103 salinity levels control (0 ds m-1) 8.80±0.2731 a 4.35±0.2264 a 13.00±0.2880 a salt stress (8 ds m-1) 7.69±0.2519 b 3.94±0.2010 b 11.49±0.2571 b level of significance ** ** ** critical value for comparison 0.0887 0.1540 0.0997 standard error for comparison 0.0439 0.0761 0.0493 cv (%) 2.06 7.12 1.56 in a column, values having same letter(s) did not differ significantly by tukey at p  5% level. ** indicates significantly different at 1% level of probability. se indicates standard error. the combined effect of mung bean accessions and salinity levels significantly interacted on early seedling traits of mung bean (table 4). among different interactions, bd-6882 produced maximum shoot length (11.44 cm) when grown under control condition which was followed by bd-10024 (10.60 cm) under control and bd-6882 (10.33 cm) under salt stress. the longest root (6.33 cm) was observed in bd-10026 under control followed by root length produced by bd-6875 (5.63 cm) under control, whereas the shortest root (2.50 cm) was recorded in bd-6884 under salt stress which was statistically at par with root length of bd-6884 (2.58 cm) under control and root length of bd-6885 (2.52 cm) under salt stress. among different treatment combinations, the maximum dry matter plant-1 (15.69 mg plant-1) was recorded in bd-10024 under control condition followed by that of bd-6884 (14.45 mg plant−1) under control, while the minimum value of the trait (9.46 mg plant−1) was found in bd-6887 under salt stress. salt stress significantly reduced the seedling traits in all mung bean accessions but the degrees of reduction were different in different accessions. the degrees of reduction were 13.24, 9.70, 18.19, 9.23, 10.59, 13.45, 8.36, 13.96, 10.16 and 19.37% in shoot length; 5.15, 5.07, 3.10, 7.01, 11.38, 9.57, 9.94, 9.95, 15.32 and 15.73% in root length and 17.78, 6.77, 16.19, 12.04, 12.81, 8.45, 10.85, 9.18, 10.50 and 11.05% in seedling dry weight in bd-6875, bd-6882, bd-6884, bd-6885, bd-6887, bd-10022, bd10023, bd-10024, bd-10026 and bd-10027, respectively. table 4. interaction effect of mung bean accessions and salinity levels on early seedling traits of mung bean mung bean accessions salinity levels shoot length (cm) % change over control root length (cm) % change over control seedling dry weight (mg plant−1) % change over control bd-6875 control 7.78 gh -13.24 5.63 ab -5.15 13.50 d -17.78 salt stress 6.75 jk 5.34 bc 11.10 hi bd-6882 control 11.44 a -9.70 4.93 b-d -5.07 10.93 h-j -6.77 salt stress 10.33 b 4.68 c-f 10.19 k bd-6884 control 8.74 de -18.19 2.58 j -3.10 14.45 b -16.19 salt stress 7.15 ij 2.50 j 12.11 ef bd-6885 control 7.37 hi -9.23 2.71 ij -7.01 11.88 fg -12.04 salt stress 6.69 jk 2.52 j 10.45 jk bd-6887 control 6.42 k -10.59 3.78f gh -11.38 10.85 ij -12.81 salt stress 5.74 l 3.35g h-j 9.46 l bd-10022 control 9.44 c -13.45 5.33 bc -9.57 12.55 e -8.45 salt stress 8.17 fg 4.82 b-e 11.49 gh evaluation of mung bean accessions for salt tolerance 22 bd-10023 control 9.33 c -8.36 4.73 b-e -9.94 13.83 cd -10.85 salt stress 8.55 ef 4.26 d-g 12.33 ef bd-10024 control 10.60 b -13.96 3.92 e-g -9.95 15.69 a -9.18 salt stress 9.12 cd 3.53 g-i 14.25 bc bd-10026 control 8.66 d-f -10.16 6.33 a -15.32 12.66 e -10.50 salt stress 7.78 gh 5.36 bc 11.33 g-i bd-10027 control 8.26 e-g -19.37 3.56 g-i -15.73 13.66 cd -11.05 salt stress 6.66 jk 3.00 h-j 12.15 ef level of significance ** * ** critical value for comparison 0.5269 0.9146 0.5924 standard error for comparison 0.1387 0.2408 0.1560 cv (%) 2.06 7.12 1.56 in a column, values having same letter(s) did not differ significantly by tukey at p  5% level. ** and * indicate significantly different at 1% and 5% level of probability. se indicates standard error. salt stress caused a significant reduction in early seedling growth and associated developmental parameters which was due to reduction in root and shoot lengths with considerable genotypic variations. growth inhibition under salt stress may be due to the diversion of energy from growth to maintenance (greenway and gibbs, 2003). salt stress caused low intra-cellular water potential and water scarcity around the root zone due to which roots failed to absorb sufficient water and nutrients for adequate plant growth (sunil et al., 2012). salinity suppressed the uptake of essential nutrients like p and k (nasim et al., 2008), which could adversely affect seedling growth and vigor. significant reduction in term of shoot length, root length and seedling dry weight among the mung bean accessions might be attributed to their differential response in term of sensitivity to salt stress. reduction in seedling dry weight also might be due to inability to accumulate respiratory product to mung bean seedlings. the results are in accordance of findings of aziz et al. (2016), kumawat and gothwal (2020) and sarkar and kundagrami (2021) who concluded that seedling dry weight of mung bean accessions was affected to a greater extent under salt stress condition. correlation analysis among different germination and early seedling traits correlation analysis among different germination and early seedling traits of different mung bean accessions presented in table 5 designates that all the traits maintained a significant positive correlation with each other. table 5. correlations (pearson) among the different germination and seedling traits of mung bean accessions germination percentage rate of germination co-efficient of germination shoot length (cm) root length (cm) seedling dry weight (mg plant−1) germination percentage 1.0000** rate of germination 0.9931** 1.0000** co-efficient of germination 0.7957** 0.8105** 1.0000** shoot length 0.4502** 0.4531** 0.5116** 1.0000** root length 0.5807** 0.5925** 0.5979** 0.3619** 1.0000** seedling dry weight 0.4855** 0.4842** 0.3592** 0.3445* 0.4593** 1.0000** ** and * indicate significant at the 1% and 5% probability level, respectively. stress tolerance index based on germination and seedling traits stress tolerance index of mung bean accessions based on different germination and early seedling traits (table 6) indicates different levels of salt tolerance of mung bean under nacl induced salt stress. 23 miajy et al. table 6. stress tolerance index of mung bean accessions based on germination and seedling traits mung bean accessions salt tolerance index germination percentage rate of germination co-efficient of germination shoot length (cm) root length(cm) seedling dry weight (mg plant−1) bd-6875 0.97 0.94 0.88 0.87 0.95 0.82 bd-6882 0.89 0.89 0.92 0.90 0.95 0.93 bd-6884 0.85 0.86 0.93 0.82 0.97 0.84 bd-6885 0.72 0.71 1.02 0.91 0.93 0.88 bd-6887 0.68 0.68 0.75 0.89 0.87 0.87 bd-10022 0.91 0.88 0.86 0.86 0.90 0.91 bd-10023 0.72 0.68 0.78 0.92 0.90 0.89 bd-10024 0.96 0.96 0.96 0.86 0.90 0.91 bd-10026 0.91 0.88 0.88 0.90 0.85 0.89 bd-10027 0.71 0.67 0.84 0.81 0.84 0.89 the accession with high sti showed more tolerance to stress condition than the other accessions. the order of stress tolerance index of mung bean accessions was bd-6875 > bd-10024> bd-10026 > bd-10022 > bd-6882> bd-6884 > bd-6885> bd-10023> bd-10027> bd-6887based on germination percentage, bd-10024 >bd-6875 > bd-6882 > bd-10026 > bd-10022 > bd-6884 >bd6885 > bd-6887 > bd-10023> bd-10027 based on rate of germination, bd-6885> bd-10024> bd6884> bd-6882> bd-10026> bd-6875> bd-10022> bd-10027> bd-10023> bd-6887 based on coefficient of germination, bd-10023> bd-6885> bd-6882 > bd-10026 > bd-6887 > bd-6875 > bd10022 > bd-10024 > bd-6884 > bd-10027 based on shoot length, bd-6884 > bd-6882 > bd-6875 > bd-6885 > bd-10022> bd-10023 > bd-10024 > bd-6887 > bd-10026 > bd->10027 based on root length and bd-6882 > bd-10022 bd-10024 > bd-10026 > bd-10023 > bd-10027 > bd-6885> bd6887> bd-6884>bd-6875 based on seedling dry weight. other researchers (hooshmandi, 2019; haque et al., 2021; pramanik et al., 2022a and pramanik et al., 2022b) also used sti as an important tolerance criterion for plant in stress conditions. salt tolerance based on relative total dry weight seedling−1 the relative total dry matter (tdm) per seedling (% tdm to control conditions) was significantly reduced in different degrees due to salt stress in all the accessions evaluated (table 7). table 7. comparative salt tolerance group of mung bean accessions based on relative total dry weight of seedling mung bean accessions value (%) scale rating bd-6882 93 2 tolerant bd-10022 91 2 tolerant bd-10024 91 2 tolerant bd-10023 89 3 moderately tolerant bd-10026 89 3 moderately tolerant bd-10027 89 3 moderately tolerant bd-6885 88 3 moderately tolerant bd-6887 87 3 moderately tolerant bd-6884 84 3 moderately tolerant bd-6875 82 3 moderately tolerant the accessions tested in this study were considered to be classified into ten groups using 0-9 scale and then categorized as tolerant (rtdw > 90%), moderately tolerant (rtdw is in the range of 7090%), susceptible (rtdw is in the range of 50-70% respectively) and highly susceptible (rtdw < 50%) (ashraf and waheed, 1990). there were three accessions (bd-6882, bd-10022 and bd-10024) that produced greater than 90% rtdw and were identified as tolerant to salinity. other seven accessions had rtdw in the range of 70-90% and were categorized as moderately tolerant to salinity. evaluation of mung bean accessions for salt tolerance 24 in the third (susceptible) and fourth (highly susceptible) group, there was no accession. among the 10 accessions, 30% accession was found as tolerant and other 70% was found as moderately tolerant based on rtdw seedling−1. the relative total dry weight is an important indicator for evaluating salt tolerance in plants which is most usefully presented in terms of relative production over a range of salinities (sarkar and kundagrami 2021 and uddin et al., 2017). aziz et al. (2016) also considered the percent of relative total dry weight for calculating salt tolerance levels of 50 mung bean genotypes that shows conformity with the findings of our study. conclusion the essential requirement of a successful breeding program of any crop is collection and evaluation of germplasm having desirable variability for economically important and environmentally sustainable characters. the response to salt stress is a complex phenomenon and according to genetic variability of the genotypes the response of genotypes to stress varied. from this study, it is observed that salt tolerant accession was found to be less affected by the salt stress and produced better tdm compared to other accessions. based on rtdw, three accessions viz. bd-6882, bd-10022 and bd10024 were screened to be the tolerant to salt stress, whereas other seven accessions were found as moderately tolerant. these accessions may be useful resources for future breeding programs to develop salt tolerant mung bean genotype. references alom, r., m.a. hasan, m.r. islam and q.f. wang. 2016. germination characters and early seedling growth of wheat (triticum aestivum l.) genotypes under salt stress conditions. j. crop sci. biotech. 19(5): 383-392. arslan, a., g.a. majid, k. abdallah, p. rameshwaran, r. ragab, m. singh and m. qadir. 2016. evaluating the productivity potential of chickpea, lentil and faba bean under saline water irrigation systems. irrig. drain. 65:19-28. ashraf, m., and e. rasul. 1988. salt tolerance of mungbean (vigna radiata (l.) wilezek) at two growth stages. plant soil 110: 63-67. ashraf, m., m.h. bokhari and a. waheed. 1990. screening of local/exotic accessions of mungbean (vigna radiata (l.) wilczek) for salt tolerance. japan. j. trop. agric. 34(3): 169-175. atak, m., m.d. kaya, g. kaya, y. çikili and c.y. çiftçi. 2006. effects of nacl on the germination, seedling growth and water uptake of triticale. turk. j. agric. for. 30(1): 39-47. aziz, m.a., m.a. karim, a. hamid, q.a. khaliq, m. hossain and a.j.m.s. karim. 2016. salt tolerance in mungbean: screening of mungbean genotypes against salinity stress at early vegetative stage. in: unfavourable ecosystem: crop production under salinity stress, agronomy division. bangladesh agricultural research institute, gazipur. pp. 1-6. bangar, p., a. chaudhury, b. tiwari, s. kumar, r. kumari and k. venkataramana. 2019. morphophysiological and biochemical response of mungbean (vigna radiata l. wilczek) varieties at different developmental stages under drought stress. turkish j. biol. 43(1): 58-69. bayuelo-jiménez, j.s., r. craig and j.p. lynch. 2002. salinity tolerance of phaseolus species during germination and early seedling growth. crop sci. 42(5): 1584-94. bbs. 2022. yearbook of agricultural statistics, bangladesh bureau of statistics, statistics and informatics division, ministry of planning, govt. of the people’s republic of bangladesh, dhaka bangladesh. copeland, l.o. 1976. principles of seed science and technology. burgess publication company, minneapolis, minnesota. pp. 164. goudarzi, m. and h. pakniyat. 2008. evaluation of wheat cultivars under salinity stress based on some agronomic and physiological traits. j. agri. soc. sci. 4: 35-38. greenway, h. and j. gibbs. 2003. mechanisms of anoxia tolerance in plants. ii. energy requirements for maintenance and energy distribution to essential processes. funct. plant biol. 30(10): 999-1036. haleem, a.h.e.s. 2015. seed germination percentage and early seedling establishment of five (vigna unguiculata l. (walp) genotypes under salt stress. eur. j. exp. biol. 5: 22-32. haque, m.n., s.k. pramanik, m.a. hasan and s. sikder. 2021. evaluation of drought tolerance in hybrid maize based on selected morpho-physiological and yield traits. j. sci. tech. 20-31. 25 miajy et al. hasanuzzaman, m., k. nahar and m. fujita. 2013. plant response to salt stress and role of exogenous protectants to mitigate salt-induced damages. in: ecophysiology and responses of plants under salt stress, p. ahmad, m.m. azooz and m.n.v. prasad (eds.). springer, new york. pp. 25-87. hasanuzzaman, m., m.a. hossain and m. fujita. 2012. plant responses and tolerance to abiotic oxidative stress: antioxidant defenses is a key factor. in: crop stress and its management: perspective and strategies, b. venkateswarlu, a.k. shanker, c. shanker and m. maheswari (eds.). springer, germany. pp. 261-316. hooshmandi, b. 2019. evaluation of tolerance to drought stress in wheat genotypes. idesia. 37(2): 37-43. jamil, a., s. riaz, m. ashraf and m.r. foolad. 2011. gene expression profiling of plants under salt stress. crit. rev. plant sci. 30(5): 435-458. kamrul, h.m., m.s. islam, m.r. islam, h.n. ismaan and a. el sabagh. 2018. germination and early seedling growth of mungbean (vigna radiata l.) as influenced by salinity. azarean j. agric. 5(2):49-59. kannaiyan, s. 1999. bioresource technology for sustainable agriculture. associated publishing com, agra, pp. 422. kazal, v., b. bhushan, r.k. narwal, s. kumar and a. pal. 2017. evaluation of salt tolerance in different isabgol (plantago ovata forsk.) genotypes under differential salt stress imposition. indian j. agri. biochem. 30(1): 41-49. krishnasamy, v. and d.v. seshu. 1990. germination after accelerated aging and associated characters in rice varieties. seed sci. tech. 18: 353. kumawat, c.k. and d.k. gothwal. 2020. effect of salinity on germination and seedling growth in mungbean (vigna radiata l. wilczek) genotypes. j. pharmacog. phytochem. 9(4): 1737-1741. mahmuduzzaman, m., z.u. ahmed, a.k.m. nuruzzaman and f.r.s ahmed. 2014. causes of salinity intrusion in coastal belt of bangladesh. int. j. plant res. 4(4): 8-13. nasim, m.r., t. qures, m. aziz, s. saqib, s.t. nawaz and s. pervaiz. 2008. growth and ionic composition of salt stressed eucalyptus camadulensis and eucalyptus teretcomis. pakistan j. bot. 40: 799-805. potter, n.n. and j.h. hotchkiss. 1998. fats, oils and related products. 5th edn. pp. 403. pramanik, s.k., s. sikder and m.a. hasan. 2022a. pheno-physiological and yield responses of wheat to water deficit stress condition. j. sci. tech. 20: 9-21. pramanik, s.k., s. sikder and m.a. hasan. 2022b. polyethylene glycol mediated osmotic stress on germination, seedling traits and seed metabolic efficiency of wheat. bangladesh agron. j. 25(2): 19-29. pratap, a., s. gupta, s. basu, r. tomar, s. dubey and rathore m. 2019. towards development of limate-smart mungbean: challenges and opportunities. in: genomic designing of climate smart pulse crops, c. kole (eds.). springer, cham, new york. pp. 235–264. roundy, b.a. 1983. response of basin wild rye and tall wheat grass shoot to salination. agro. j. 75: 67-71. saha, p., p. chatterjee and a.k. biswas. 2010. nacl pretreatment alleviates salt stress by enhancement of antioxidant defense and osmolyte accumulation in mungbean (vignaradiata l. wilczek). indian j. exp. biol. 48: 593600. sanchez, p.l., m.k. chen, m. pessarakli, h.j. hill, m.a. gore and m.a. jenks. 2014. effects of temperature and salinity on germination of non-pelleted and pelleted guayule (parthenium argentatum a. gray) seeds. indian crops prod. 55: 90-96. sarkar, m. and s. kundagrami. 2021. screening of mungbean accessions under salinity stress. bangladesh j. bot. 50(3): 475-482. sehrawat, n. and p.k. jaiwal. 2014. evaluation of mungbean genotype at early seedling growth stage. biocatalysis and agri. biotech. 3: 108-113. sehrawat, n., k.v. bhat, r.k. sairam and p.k. jaiwal. 2013. screening of mungbean (vigna radiata l. wilczek) genotypes for salt tolerance. int. j. plant env. sci. 4: 36-43. sunil, k.b., m. prakash, s. narayanan and j. gokulakrishnan. 2012. breeding for salinity tolerance in mungbean. in: 2nd international conference on asia agriculture and animal (icaaa). apcbee procedia 4: 30-35. swarnakar, a. 2016. mitigation of toxic effects of sodium arsenate on germination, seedling growth and amylolytic enzyme of mungbean seedlings with macronutrients, micronutrients and organic acids. int. j. curr. microbiol. appl. sci. 5(12): 151-160. thomas, m., j. robertson, s. fukai and m.b. peoples. 2004. the effect of timing and severity of water deficit on growth development, yield accumulation and nitrogen fixation of mungbean. field crops res. 86: 67-80. uddin, m.s., n. jahan and m.a. monim. 2017. growth and salinity tolerance of wheat genotypes at early vegetative stage. progress. agric. 28(1): 12-17. win, t., a.z. oo, t. hirasawa, t. ookawa and h. yutaka. 2011. genetic analysis of myanmar vigna species in responses to salt stress at the seedling stage. afr. j. biotechnol. 10(9): 1615-1624. zahedi, a.m., i. fazeli, m. zavareh, h. dorry and n. gerayeli. 2012. evaluation of the sensitive components in seedling growth of common bean (phaseolus vulgaris l.) affected by salinity. asian j. crop sci. 4(4): 159-164. evaluation of mung bean accessions for salt tolerance 26 zhang, h., l.j. irving, c. mcgill, c. matthew, d. zhou, p. kemp, h. zhang, l.j. irving, c. mcgill, c. matthew and d. zhou. 2010. the effects of salinity and osmotic stress on barley germination rate: sodium as an osmotic regulator. ann. bot. 106(6): 1027-1035. bangladesh agron. j. 2022, 25(2): 67-72 grain, yield and quality of transplant aman rice and soil nutrients status with application of fertilizers and green manures z. nasrin1, m.f. karim2, m.j. ullah2, m.a. siddiquee3 and m.a. khan2 1national consultant, fao-bd, 2department of agronomy, sher-e-bangla agricultural university, dhaka1207, bangladesh, 3chief scientific officer, bangladesh rice research institute (brri), joydebpur, gazipur-1701, bangladesh. corresponding email: pdmfkarim@yahoo.com (received: 27 august 2022, accepted: 06 january 2023) keywords: mimosa, dhaincha, green manure, grain yield, grain quality, soil nutrient status abstract a field experiment was conducted at sher-e-bangla agricultural university, dhaka during 2014 on transplant aman rice var. br11 (mukta) under different levels of chemical fertilizers and green manures to evaluate its grain yield, grain quality and soil fertility status with incorporation of green manures. the experiment was carried out in a splitplot design with three replications. the level of fertilizers (0, 100, 75, 50% of recommended dose, rfd) was placed in main -plot and levels of green manures management (0, 5 and 10 t ha-1 each mimosa invisa (lajjaboti) and sesbania spp. (dhaincha) in sub-plot. recommended dose of fertilizers of 83n, 21p, 37k, 11s and 1.5 zn kg ha-1, were applied in the form of urea, triple super phosphate (tsp), muriate of potash (mop), gypsum and zinc sulfate, respectively. sixty-day old mimosa invisa and sesbania spp. were in vitro incorporated before aman transplantation. combined application of 75% rfd along with mimosa invisa @ 10 t ha-1 was proved to be the best management in producing higher grain yield (7.25 t ha-1) and that was at par with treatment 50% rfd plus mimosa invisa @ 10 t ha-1. quality of grain was increased markedly in respect of amylose, carbohydrate, and protein as well. furthermore, the treatment improved soil nutrient status in respect of organic matter, nitrogen, sulfur and zn over no incorporations of green manures. so, addition of green manure like mimosa invisa could cut fertilizer cost by 25-50%. introduction in bangladesh rice covering 11.53 million hectares (bbs, 2011) where transplant aman rice occupied 55.3 % of total rice area (bbs, 2018). continuous rice cultivation could be a threat for soil health concern. sulphur and zinc unavailability is resultant effect of continuous cultivation of aus, aman and boro (biswas and naher, 2019). in addition, imbalance use of fertilizers, limited or no use of crop residues or green manure into the soil thus triggered down the soil nutrient status of bangladesh. recently, mg, b and mo are also reported to be limiting in many areas (rahman et al., 2021). on the other hand, imbalance use of chemical fertilizers is further detrimental on the availability of soil nutrients for expression of crop production potentiality. it was notified that sustainable crops production cannot be maintained by using either alone chemical fertilizers or organic manure (moe et al., 2017). so, use of green manure/organic manure along with inorganic fertilizers is mostly scientific in improving soil fertility followed by sustainable crop production from integrated crop management (icm) point of view. dhaincha 68 nasrin et al. (sesbania spp.) is well known plant for conventional soil improving management in bangladesh (sarwar et al., 2017). mimosa invisa (lajjaboti) is an emerging green manuring legume weed is being evaluated for its potentiality towards improving of soil health and quality crop yield indeed over dhaincha (mishra et al., 2011). in bangladesh, study on the performance of mimosa as a green manure is lacking or little in practice. so, the potentiality of this novel green manure is to be tested in bangladesh crop fields. hence, the study of influence of mimosa invisa and sesbania spp. as green manure along with different fertilizers levels for improving t. aman rice grain yield in general and soil improvement in particular. materials and methods an experiment was conducted at sher-e-bangla agricultural university during 2014 aman season (july – november) to evaluate the effect of green manures on transplant aman under different levels of fertilizers. the test crop was rice var. br11 (mukta). the experiment was carried out in a splitplot design with three replications. the level of fertilizers (0, 100, 75, 50% of recommended dose, rfd) was placed in main -plot and levels of green manures management (0, 5 and 10 t ha-1 each mimosa invisa and sesbania spp. in sub-plot. the treatment comprised of fertilizer levels (4); f0 = no fertilizers (control), f1 = recommended dose (n = 83 kg ha-1, p = 21 kg ha-1, k = 37 kg ha-1, s = 11 kg ha-1, zn = 1.5 kg ha-1), f2 = 75% of the recommended dose, f3 = 50% recommended dose in main plot. green manures had 5 levels viz. g0 = no green manure (control), g1 = mimosa invisa at 5 t ha-1, g2 = mimosa invisa at 10 t ha-1, g3 = sesbania spp. at 5 t ha-1, g4 = sesbania spp. at 10 t ha-1 were considered in sub plot. sixty-day old mimosa invisa and sesbania spp. were in vitro incorporated before aman transplantation. the data on grain yield, grain quality and soil health components were recorded. grain quality analysis was done at grain quality and nutrition division, laboratory of brri, gazipur-1701 following national institute of nutrition, nin (1976). soil health quality was determined following protocol of jackson (1962), page et al. (1982), olsen et al. (1954) and black (1965). the data collected were analyzed statistically using mstatc software and mean differences of treatments were adjudged with least significant difference (lsd) test (gomez and gomez, 1984). results and discussion combined effect of fertilizer and green manure levels on grain yield of rice results revealed that grain yield was varied from 3.20 to 7.25 t ha-1 as observed with combination effect of different levels of fertilizer and green manure. the yield advantage due to f2g2 was 126.57% over control. this treatment had significantly higher grain yield (7.25 t ha-1) but followed by f3g2 (6.60 t ha-1), f1g1 (6.57 t ha-1), f2g4 (6.21 t ha-1) and f3g3 (6.18 t ha-1). the control plot gave the lowest yield (3.20 t ha-1) (table 1). the maximum yield was attributed due to increased effective tillers plant-1, panicle length, grains panicle-1 and 1000-grain weight. this might be due to balanced availability of nutrients from the fertilizers and green manures combination. the combined effect of fertilizers and green manures was found positive for increasing different yield contributing traits and yield as reflected in different reports opined by rice scientists (islam et al., 2015; abedin et al., 1999; apostol, 1989; hoque, 1999). combined effect of fertilizer and green manure levels on biochemical parameters of rice grain significantly variations in grain quality parameters were obtained with different combined treatments (table 2). the grain moisture, amylose, protein and carbohydrate content ranged grain, yield and quality of transplant aman rice and soil nutrients status with application 69 between 9.20 10.70, 23.00 27.10, 6.50 8.80 and 71.30 82.10 % in different treatments. carbohydrate and protein constituted about 88% of the total grain weight. table 1. combined effect of different levels of fertilizers and green manures on grain yield of transplant aman rice treatment combinations grain yield (t ha-1) yield advantage over control (%) f0g0 3.20 h f0g1 4.56 fg 42.50 f0g2 4.88 e-g 52.50 f0g3 4.32 g 35.00 f0g4 4.90 e-g 53.12 f1g0 5.20 d-g 62.50 f1g1 6.57 a-c 105.31 f1g2 6.12 b-d 91.25 f1g3 5.86 b-e 83.13 f1g4 5.50 c-f 71.90 f2g0 4.73 fg 47.81 f2g1 5.96 b-e 86.25 f2g2 7.25 a 126.57 f2g3 5.54 b-f 73.13 f2g4 6.21 a-d 94.06 f3g0 4.71 fg 47.19 f3g1 5.95 b-e 86.00 f3g2 6.60 ab 106.25 f3g3 6.18 a-d 93.13 f3g4 5.31 d-g 65.93 lsd(0.05) 1.09 cv (%) 12.00 f0 = no fertilizers (control) f1 = recommended dose f2 = 75% of the recommended dose f3 = 50% of the recommended dose g0 = no green manures (control) g1 = mimosa invisa at 5 t ha-1 g2 = mimosa invisa at 10 t ha-1 g3 = sesbania spp. at 5 t ha-1 g4 = sesbania spp. at 10 t ha-1 treatments f3g2 and f2g4 had similar moisture content value (10.70%) which was maximum from f1g4 (9.20%). amylose content elevated maximum (27.10%) in f3g3 and that was minimum in f2g0 (23.00%). protein content was the highest (8.80%) in f2g2 whereas minimum in f0g0 (6.50%). carbohydrate was determined greater (82.10%) in f3g4 and lower (71.30%) in f0g0. likewise, grain yield was marked that reduced fertilizer rate (50-75%) along with either mimosa or sesbania application at 5 or 10 t ha-1, increases all the grain quality parameters. protein and carbohydrate content was minimum when plant did not get any fertilizer and green manure. the results are in corroborated with findings of pramanik (2006) when he was concerned in rice grain quality with green manure application. soil health status with or without green manures application table 3 showed that incorporation of green manure into soil increased levels of organic matter (0.94 to 1.48%), total nitrogen (0.047 to 0.074%), available sulphur (3.4 to 3.73 ppm) and available zinc (5.63 to 9.13 ppm). this soil quality was improved due to the addition of higher amount of organic matter from green manure into soil. rahman et al. (2013) and sarwar et al. (2017) determined improvement of organic matter and total nitrogen content status in soil after incorporation of green manure which is in corroboration with the present findings. the increased level of sulphur indicates that green manures released sufficient sulfur due to its 70 nasrin et al. decomposition in the soil. similar results were confirmed by sanchez (1976) whereas decreased trend was evident in case of soil ph (6.30 to 6.10), available phosphorus (27.93 to 23.93 ppm) and exchangeable potassium (0.20 to 0.13 meq/100g soil). table 2. combined effect of different levels of fertilizers and green manures on grain quality of transplant aman rice treatment combinations moisture (%) amylose (%) protein (%) carbohydrate (%) f0g0 10.10 de 23.50 k 6.50 h 71.30 h f0g1 10.30 cd 26.10 bc 8.10 def 80.05 fg f0g2 10.50 abc 26.00 c 8.30 bcd 80.10 fg f0g3 10.50 abc 26.40 b 7.80 f 80.60 de f0g4 9.90 ef 23.90 ij 7.90 ef 81.10 bc f1g0 9.70 fg 25.50 d 8.50 abc 80.70 cde f1g1 9.70 fg 23.60 jk 8.30 bcd 80.90 cd f1g2 9.90 ef 24.80 fg 8.60 ab 80.40 ef f1g3 10.40 bc 25.30 de 8.40 bcd 80.10 fg f1g4 9.20 h 23.10 l 8.20 cde 81.50 b f2g0 10.30 cd 23.00 l 8.50 abc 80.10 fg f2g1 10.00 e 24.70 g 8.40 bcd 80.50 def f2g2 9.60 g 26.10 bc 8.80 a 80.80 cde f2g3 9.60 g 24.90 fg 8.50 abc 80.80 cde f2g4 10.70 a 25.10 ef 8.50 abc 79.70 g f3g0 10.10 de 23.80 ijk 7.90 ef 80.90 cd f3g1 10.10 de 24.30 h 8.20 cde 80.60 de f3g2 10.70 a 24.00 hi 8.30 bcd 79.90 g f3g3 10.60 ab 27.10 a 8.20 cde 80.10 fg f3g4 9.90 ef 24.90 fg 6.90 g 82.10 a lsd(0.05) 0.25 0.39 0.30 0.46 cv (%) 1.49 0.94 2.22 0.35 f0 = no fertilizers (control) f1 = recommended dose f2 = 75% of the recommended dose f3 = 50% of the recommended dose g0 = no green manures (control) g1 = mimosa invisa at 5 t ha-1 g2 = mimosa invisa at 10 t ha-1 g3 = sesbania spp. at 5 t ha-1 g3 = sesbania spp. at 10 t ha-1 salahin et al. (2013) opined that incorporation of green manure increases organic acid which ultimately decreases soil ph. georgantas and grigoropoulou (2006) observed that ph value less than 6 created a chemical bond between aluminum (al) and phosphate (known as phosphorus fixation), thus availability of phosphorus may be reduced on soil testing but it is good for use of this nutrient by next crop. sahu and nayak (1971) obtained a slight decline of soil k after green manure addition. table 3. chemical properties of soil as before and after incorporation of green manures chemical properties of soil pre-planting (unincorporated soil) post-harvest (after incorporation) ph 6.30 6.10 organic matter (%) 0.94 1.48 total nitrogen (%) 0.047 0.074 available phosphorus (ppm) 27.93 23.93 exchangeable potassium (meq/100g soil) 0.20 0.13 available sulphur (ppm) 3.40 3.73 available zinc (ppm) 5.63 9.13 source: soil resource development institute (srdi), khamarbari, dhaka grain, yield and quality of transplant aman rice and soil nutrients status with application 71 conclusion it could be suggested that incorporation of green manure either mimosa invisa or sesbania spp. into the soil has a positive influence in increasing grain yield, grain quality of transplanted aman rice and soil health status as well. the 75% recommended dose of fertilizers along with mimosa invisa @ 10 t ha-1 produced the highest grain yield (7.25t/ha) and at par with 50% recommended dose of fertilizers plus mimosa invisa @ 10 t ha-1. so, application of novel green manure like mimosa invisa in t. aman cultivation could reduce fertilizer cost by 25-50%. references abedin, m.j., m.a. rouf., m.h. rashid and m. eaqub. 1999. residual effects of tsp and farmyard manure under renewed application of urea on the yield of crop and some chemical properties of soil. bangladesh j. agric. sci. 10(2): 100-109. apostol, e.d.f. 1989. influence of mirasoil organic and x-rice liquid fertilizer in combination with inorganic fertilizer on ir66 and bpi ri-12 rice varieties. ph.d. thesis, gregorio araneta univ. foundation, malabon, metro manila, philippines. p. 73. bbs. 2011. statistical year book of bangladesh, bangladesh bureau of statistics, ministry of planning, government of the people’s republic of bangladesh, dhaka. bbs. 2018. bangladesh bureau of statistics. 45 years agriculture statistics of major crops (aus, amon, boro, jute, potato and wheat): 22. biswas, j.c. and u.a. naher. 2019. soil nutrient stress and rice production in bangladesh. in advances in rice research for abiotic stress tolerance, woodhead publishing. pp. 431445. black, c.a. 1965. methods of soil analysis. part i and ii. in: chemical and microbiological properties. c. a. black (ed.) american soc. agron. inc. publisher, madison, wisconsin, usa. pp. 445-567. georgantas, d.a. and h.p. grigoropoulou. 2006. phosphorus and organic matter removal from synthetic waster using alum and aluminum hydroxide. global nest j. 8(2): 121-130. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research (2nd ed.). john wiley and sons. new york. chichester, brisbane, toronto, singapore, p. 680. hoque, m.a. 1999. response of brri dhan 29 to sulfur, zinc and boron supplied from manure and fertilizers. m.s. thesis, bau, mymensingh, bangladesh. islam, m.s., n.k. paul, m.r. alam, m.r. uddin, u.k. sarker, m.a. islam and s.u. park. 2015. responses of rice to green manure and nitrogen fertilizer application. j. biol. sci. 15 (4): 207-216. jackson, m.l. 1962. soil chemical analysis. c. englewood, (ed.). prentice hall inc., n. j., usa. p. 46. mishra, a., s.k. mohanty, b. behera and c.r. subudhi. 2011. evaluation of mimosa invisa as a green manure crop in rainfed uplands. indian j. dryland agric. res. dev. 26(2): 101-104 moe, k., k.w. mg, k.k. win and t, yamakawa. 2017. effects of combined application of inorganic fertilizer and organic manures on nitrogen use and recovery efficiencies of hybrid rice (palethwe-1). american j. plant sci. 8(5): 1043. nin. 1976. national institute of nutrition. a manual of laboratory techniques. indian council of medical research, hydrabad-500007, india. pp. 1-3. olsen, s.r., c.v. cole, f.s. watanable and l.a. dean. 1954. estimation of available phosphours in soil by extraction with sodium biocarbonate. u.s. dept. agric. circ. 939. 72 nasrin et al. page, a.l., r.h. miller and d.r. keeney. 1982. methods of soil analysis, part-2. amer. soc. agron. madi, usa. pp. 539-622. pramanik, m.y.a. 2006. effect of green manuring on transplant aman rice and its residual effect on subsequent boro rice. ph.d. thesis, bau, mymensingh, bangladesh. rahman, m., m.m.r. jahangir, m.g. kibria, m. hossain, m. hosenuzzaman, z.m. solaiman and m.a. abedin. 2021. determination of critical limit of zinc for rice (oryza sativa l.) and potato (solanum tuberosuml.) cultivation in floodplain soils of bangladesh. sustainability. 14(1), 167. rahman, m.h., m.r. islam, m. jahiruddin, m.y. rafii, m.m. hanafi and m.a. malek. 2013. integrated nutrient management in maize-legume-rice cropping pattern and its impact on soil fertility. j. food agric. environ. 11(2): 648-652. sahu, b.n. and b.c. nayak. 1971. soil fertility investigations under continuous application of ammonium sulphate alone and in combination with organic manure in the bhubneshwar long term fertility trials. proc. int. symp. on soil fertility evaln. new delhi, india. 1: 873979. salahin, n., m.k. alam, m.m. islam, l. naher and n.m. majid. 2013. effects of green manure crops and tillage practice on maize and rice yields and soil properties. aust. j. crop sci. 7(12): 1901-1911. sanchez, p.a. 1976. properties and management of soils in the tropics. john wiley and sons. n.y. p. 618. sarwar, a.k.m.g., s.m.z. hossain and s.c. chanda. 2017. effect of dhaincha accessions on soil health and grain yield of rice. j. bio sci. agric. res. 13: 1140-1145. microsoft word 10. baj-477e bangladesh agron. j. 2024, 26(2): 77-85 foliar fertilization on brri dhan28 to reduce soil application of nitrogenous fertilizer m.a.j. mohona, m.a. hasan, a.k.m.m.b. chowdhury, m.h.r. hafiz, m.r. islam and s. sharmin* department of crop physiology and ecology, hajee mohammad danesh science and technology university, dinajpur 5200, bangladesh *corresponding author: email: seulisharminhstu@gmail.com (received: 9 may 2024, accepted: 24 june 2024) keywords: foliar fertilization, brri dhan28, nitrogen fertilizer, yield abstract the experiment was conducted at the research farm of crop physiology and ecology department, hajee mohammad danesh science and technology university (hstu), dinajpur during november 2019 to june 2020 to find out the effect of foliar fertilization on the performance of rice var. brri dhan28 and to estimate how much nitrogenous fertilizer can be saved by foliar fertilization without yield reduction. the experiment was laid out following split plot design with three replications. four levels of foliar fertilization (f0 – no foliar fertilization, f1 – foliar fertilization with 2% kno3, f2 foliar fertilization with 2% dap and f3 foliar fertilization with 1% american npks) were placed in the main plot treatments whereas three nitrogen fertilizer levels (n50 -50% of the recommended nitrogen fertilizer, n75 – 75% of the recommended nitrogen fertilizer and n100 – 100% of the recommended nitrogen fertilizer) were placed randomly in the sub-plots. foliar fertilization with kno3, dap (di-ammonium phosphate) and american npks significantly increased the grain yield (t ha−1) compare to control (f0) but kno3 and american npks performed better than dap. foliar fertilization with kno3 and american npks could save 25% of recommended nitrogen fertilizer but foliar fertilization with dap could not save nitrogen fertilizer applied in soil for getting comparable grain yield found in f0n100. foliar fertilization of kno3 and american npks with recommended nitrogen fertilizer applied in soil could increase 11.8 and 12.5% grain yield, respectively compare to f0n100. introduction rice (oryza sativa l.) is one of the most important crops in bangladesh in terms of acreage and production but the average grain yield is very low (2 t ha−1) as compared to egypt (8.4 t ha−1) and usa (6.6 t ha−1). there are many reasons for lower yield of rice and among these the most important is the indiscriminate and improper application of nutrients with unfavorable condition. many factors determine the fertilizer efficiency for rice crop during cultivation such as soil, cultivar, season, environment, planting time, water management, weed control, time and methods of fertilizer application (de datta, 1978). nutrient management practices determine the sustainability of the most intensively cropping systems (flinn et al., 1982). foliar application is well recognized and is being practiced in agriculturally advanced countries. in many cases aerial spray of nutrients is preferred and gives quicker and better results than the soil application (jamal et al., 2006). fageria et al. (2009) also reported that crops respond to soil applied fertilizers in five to six days, while the response is faster (48 hours) in foliar application. foliar application increase nutrients uptake at critical growth stages and resulted in enhanced physiological activity leading to increase yield (kundu and sarkar, 2009). foliar fertilization has great advantage because of low application rates, uniform distribution of fertilizer, reduction in plant stress, plant's natural defense mechanisms to resist plant disease and insect infestations, improvement of plant health and yield (finck, 1982). ali et al. (2005) reported that foliar spray increased the metabolic activity of plant. nitrogen fertilizer is more urgent for security rice production. sharief et al. (2006) found that increasing nitrogen fertilizer levels had significant effect on yield and yield attributes of rice. hasewaga et al. (2000) reported that foliar fertilizers have significant influences of growth and rice paddy yield. ahamad and jabeen (2005) indicated that foliar nutrition 78 mohona et al. generally increases the grain yield as well as decreases the amount of fertilizers which applied as soil application. pramanik et al. (2015) showed that foliar application of fertilizer can increase rice growth and decrease the chemical fertilizer usage. alam et al. (2010) opined that foliar application could be considered only as a supplement to soil application of n. however, foliar fertilization is supplementary to and cannot replace the basal fertilization. keeping in view the study was therefore designed to find out the effect of foliar fertilization on the performance of brri dhan28 and to estimate how much nitrogenous fertilizer can be saved by foliar fertilization without yield reduction. materials and methods the experiment was set up at the research farm of crop physiology and ecology department, hajee mohammad danesh science and technology university (hstu), dinajpur during november 2019 to june 2020. the experimental field was a medium high land belonging to the non-calcareous dark gray floodplain soil under the agro-ecological zone (aez-1) of old himalayan piedmont plain. the soil is sandy loam under the order inceptisol. the initial soil contained 1.28% organic matter, 0.064% nitrogen, 18.56 µg /g phosphorous and 0.18 me / 100g potassium. the experimental site is situated in the sub-tropical region characterized by heavy rainfall during the months from may to september and scantly rainfall in the rest of the year. the experiment was conducted in a split plot design with three replications. four levels of foliar fertilization viz. f0 – n0 foliar fertilization, f1– foliar fertilization with 2% kno3, f2 – foliar fertilization with 2% dap and f3foliar fertilization with 1% american npks were placed in the main plot treatments whereas three nitrogen fertilizer levels viz. n50 – 50% of the recommended nitrogen fertilizer, n75 – 75% of the recommended nitrogen fertilizer and n100 – 100% of the recommended nitrogen fertilizer were placed randomly in the sub plots as sub plot treatments. rice var. brri dhan28 was used. seedbed was prepared and seeds were sown uniformly on 1 december 2019 to obtain 34 days old seedling at transplanting date 3 january, 2020. after land preparation, cow dung and full doses of tsp, mop, gypsum, and zinc sulphate were incorporated thoroughly into the soil as basal dose. urea was splited into equal amount in three times i.e. basal application during land preparation, rapid tillering and before panicle initiation. fertilizer was applied at a recommended rate of 300–100–160– 111.2–5.58 kg ha−1 as urea, triple supper phosphate (tsp), muriate of potash (mop), gypsum, and zinc sulphate (barc, 2018). thirty-four days old seedlings were carefully uprooted from a seedling nursery and planted on well puddle unit plots. three healthy seedlings were transplanted in each hill. intensive cares were taken during the growing period to ensure adequate growth and development of the crop. 2% kno3, 2% di-ammonium phosphate, and 1% american npks solution were prepared and applied in the respective plot for three times at 20 days interval starting from 40 days after transplanting. american npks is a foliar applied mixed fertilizer providing four major nutrient elements of nitrogen, phosphorous, potassium and sulphur with a grade mixing ratio of 8:20:14:5. american npks is also a complete fertilizer as it contains all three principal elements extremely essential for overall plants growth and development. usa company stoller markets american npks fertilizer. weeding, gap filling and other intercultural operations were done as when necessary. data were collected on plant height in cm at 60 and 75 days after transplanting and also at harvest, tillers hill−1 at 60 and 75 days after transplanting and also at harvest, panicles hill−1, panicle length (cm), spikelets panicle−1, grains panicle−1, unfilled spikelet per panicle, 1000-grain weight, grain yield per hill, straw yield (g hill−1) and grain yield (t ha−1). the data were analyzed and means were separated by tukey’s test by partitioning the total variance as described by gomez and gomez (1984). results and discussion plant height and tillers hill−1 at different days after transplanting plant height and number of tillers hill-1of brri dhan28 were not significantly influenced by foliar fertilization, nitrogen levels and their interaction effect at 60 days after transplanting (table 1). foliar fertilization on brri dhan28 to reduce application of nitrogenous fertilizer 79 table 1. effect of foliar fertilization and nitrogen levels on plant height and tillers hill−1 of brri dhan28 at different days after transplanting (dat) treatment plant height (cm) tillers hill−1 at 60 dat at 75 dat at 60 dat at 75 dat foliar fertilization f0 49.52 63.37 13.67 17.07 f1 48.07 64.22 12.52 17.41 f2 48.89 63.25 13.70 16.70 f3 46.89 63.67 11.96 16.45 significance level ns ns ns ns cv (%) 12.17 5.82 25.70 9.74 nitrogen levels n50 47.17 61.25 b 12.14 15.36 b n75 49.58 64.19 ab 13.28 17.31 a n100 48.28 65.44 a 13.47 18.06 a significance level ns * ns ** cv (%) 6.01 5.67 17.03 8.33 foliar fertilization × nitrogen levels f0n50 50.22 63.67 11.67 16.78 ab f0n75 50.55 64.33 15.11 18.33 ab f0n100 47.78 62.11 14.22 16.11ab f1n50 45.33 62.89 11.89 13.67 b f1n75 50.22 65.78 13.34 19.89 a f1n100 48.67 64.00 12.33 18.67 a f2n50 46.89 59.66 13.00 15.56 ab f2n75 50.22 63.55 13.67 15.56 ab f2n100 49.56 66.55 14.44 19.00 a f3n50 46.28 58.78 12.00 15.45 ab f3n75 47.33 63.11 11.00 15.45 ab f3n100 47.11 69.11 12.89 18.44 ab significance level ns ns ns ** cv (%) 6.01 5.67 17.03 8.33 in a column, means followed by different letter(s) within main and interaction effect differed significantly at p ≤ 5% level of probability by tukey’s test here, f0 = no foliar fertilization, f1 = foliar fertilization with kno3, f2 = foliar fertilization with dap, f3 = foliar fertilization with american npks, n50 = 50% of the recommended nitrogen fertilizer, n75 = 75% of the recommended nitrogen fertilizer, n100 = 100% of the recommended nitrogen fertilizer, ns indicates insignificant, ** indicates significant at 1% level of probability at 75 days after transplanting, number of tillers hill-1 of brri dhan28 was significantly influenced by nitrogen levels and the interaction effect of foliar fertilization and nitrogen levels but foliar fertilization had no significant influence on number of tillers hill−1 (table 1). at 75 days after transplanting, the maximum number of tillers hill−1 (18.06) was recorded from n100 which was statistically similar to n75 (17.31). the lowest tillers hill−1 (15.36) was obtained from n50. among the treatment combinations, the maximum number of tillers hill−1 was obtained from f1n75 (19.89) which was statistically similar to those recorded from all other treatment combinations except f1n50 which provided the lowest number of tillers hill−1 (13.67). the results of the present study were also supported by the findings of swaroopa and lakshmi (2015), shafiee et al. (2013) and shayganya et al. (2011). plant height and tillers hill-1 at harvest plant height of brri dhan28 at harvest was significantly influenced by foliar fertilization, nitrogen levels and their interaction effect of foliar fertilization and nitrogen levels (table 2). among the treatment combinations, the maximum plant height was obtained from f3n100 (96.17 cm) which was statistically similar to f3n75. while f0n50 treatment combination provided the lowest plant height (85.50 cm). foliar fertilization with kno3 could not save soil application of nitrogen fertilizer for getting comparable plant height found in f0n100. this is in line with the findings of mohan et al. (2017), pramanik et al. (2015) and rabin et al. (2016). 80 mohona et al. the number of tillers hill-1 was influenced significantly by nitrogen levels and the interaction effect of foliar fertilization and nitrogen levels but it was not influenced significantly by foliar fertilization (table 2). among the treatment combinations, the maximum number of tillers hill-1 was recorded in f2n100 (15.60) followed by f3n100 (15.60) which was statistically similar to all other treatment combinations except f0n50 (12.00) and f2n50 (12.13). foliar fertilization with kno3 and american npks could save 50% of recommended nitrogen fertilizer and foliar fertilization with dap could save 25% of recommended nitrogen fertilizer applied in soil for getting comparable number of tillers hill-1 was found in f0n100. the result in tiller production is with line as reported by swaroopa and lakshmi (2015), pramanik et al. (2015) and rabin et al. (2016). table 2. effect of foliar fertilization and nitrogen levels on plant height and tillers hill-1 of brri dhan28 at harvest foliar fertilization plant height (cm) tillers hill-1 nitrogen levels mean of foliar fertilization nitrogen levels mean of foliar fertilization n50 n75 n100 n50 n75 n100 f0 85.50 f 89.10 de 92.03 b 88.89 c 12.00 b 13.20 ab 13.93 ab 13.04 f1 87.60 e 90.00 cd 91.50 bc 89.70 c 13.27 ab 13.33 ab 15.60 a 14.07 f2 88.10 de 92.60 b 93.03 b 91.24 b 12.13 b 15.40 a 15.60 a 14.38 f3 89.32 de 95.50 a 96.17 a 93.66 a 14.33 ab 14.53 ab 15.53 a 14.80 mean of nitrogen levels 87.63 c 91.81 b 93.18 a 12.93 c 14.12 b 15.17 a cv (%) 5.72 5.56 level of significance ** * means followed by different capital letter(s) for main effect and small letter (s) for interaction differed significantly at p ≤ 5% level of probability by tukey’s test cv for foliar fertilization (plant height and tillers hill−1) = 5.55% and 8.40% cv for nitrogen levels (plant height and tillers hill−1) = 5.72% and 5.56% number of panicles and panicle length number of panicles hill−1 of brri dhan28 was significantly influenced by foliar fertilization, nitrogen levels and their combination effect of foliar fertilization and nitrogen levels (table 3). panicle length (cm) of brri dhan28 was not significantly influenced by foliar fertilization, nitrogen levels and their combination effect of foliar fertilization and nitrogen levels (table 3). among the treatment combinations, the highest number of panicles hill−1 was obtained from f1n100 (14.40) which was statistically similar to those recorded from f3n100 (14.07), f3n75 (13.60), f2n100 (13.53) and f1n75 (13.47). the lowest number of panicles hill−1 was obtained from f0n50 (9.60) which was statistically at par with f2n50 (10.20). foliar fertilization with kno3 could save 50% of recommended nitrogen fertilizer and foliar fertilization with dap and american npks could save 25% of recommended nitrogen fertilizer applied in soil for getting equivalent number of panicles hill-1 found in f0n100. these results are in agreement with the findings of jothi et al. (2019) and rani et al. (2014). table 3. effect of foliar fertilization and nitrogen levels on panicles hill−1 and panicle length of brri dhan28 foliar fertilization panicles hill−1 panicle length (cm) nitrogen levels mean of foliar fertilization nitrogen levels mean of foliar fertilization n50 n75 n100 n50 n75 n100 f0 9.60 e 11.60 cd 13.20 ab 11.47 b 20.12 22.00 21.57 21.23 f1 12.53 bc 13.47 ab 14.40 a 13.47 a 20.30 22.13 21.67 21.28 f2 10.20 de 12.20 bc 13.53 ab 11.98 b 22.10 20.58 21.67 21.45 f3 11.33 cd 13.60 ab 14.07 a 13.00 a 22.00 22.10 21.60 21.90 mean of 10.92 c 12.72 b 13.80 a 21.07 21.70 21.63 foliar fertilization on brri dhan28 to reduce application of nitrogenous fertilizer 81 nitrogen levels cv (%) 3.24 7.94 level of significance ** ns means followed by different capital letter(s) for main effect and small letter (s) for interaction differed significantly at p ≤ 5% level of probability by tukey’s test cv for foliar fertilization (panicles hill−1 and panicle length) = 3.62% and 3.62% cv for nitrogen levels (panicles hill−1 and panicle length) = 3.24% and 7.94% spikelets panicle−1 and grains panicle−1 foliar fertilization, nitrogen levels and their interaction had significant influence on number of spikelets panicle−1 and number of grains panicle−1of brri dhan28 (table 4). table 4. effect of foliar fertilization and nitrogen levels on spikelets panicle−1 and grains−1 panicle of brri dhan28 foliar fertilization spikelets panicle−1 grains panicle−1 nitrogen levels mean of foliar fertilization nitrogen levels mean of foliar fertilization n50 n75 n100 n50 n75 n100 f0 110 f 141 e 165 a-d 139 c 76 g 102 ef 129 c 102 c f1 158 b-e 166 a-d 176 ab 166 a 114 d 129 c 143 ab 129 a f2 138 e 148 de 168 a-d 152 b 92 f 111 de 131 c 111 b f3 151 c-e 170 a-c 180 a 167 a 115 d 132 bc 144 a 130 a mean of nitrogen levels 139 c 157 b 172 a 99 c 119 b 137 a cv (%) 4.53 2.74 level of significance * ** means followed by different capital letter(s) for main effect and small letter (s) for interaction differed significantly at p ≤ 5% level of probability by tukey’s test cv for foliar fertilization (spikelets panicle−1 and grains panicle−1) = 4.68% and 2.85% cv for nitrogen levels (spikelets panicle−1 and grains panicle−1) = 4.53% and 2.74% among the treatment combinations, the maximum number of spikelets panicle−1 (180) was recorded in f3n100 which was statistically similar to f1n100 (176), f3n75 (170), f2n100 (168), f1n75 (166), f0n100 (165). the lowest number of spikelets panicle−1 was obtained from f0n50 (110) which was followed by f2n50 (138) and f0n75 (141). foliar fertilization with kno3 and american npks could save 50% of recommended nitrogen fertilizer and foliar fertilization with dap could save 25% of recommended nitrogen fertilizer applied in soil for getting statistically similar number of spikelets panicle−1 found in f0n100. similar trend has been reported by jagathjothi et al. (2012), manik et al. (2016) and hasan et al. (2020). among the treatment combinations, the maximum number of grains panicle−1 (144) was recorded in f3n100 which was statistically similar to f1n100 (143). the lowest number of grains panicle−1 was obtained from f0n50 (76) which was followed by f2n50 (92), f0n75 (102), f2n75 (111), f1n50 (1114) and f3n50 (115). foliar fertilization with kno3 and american npks could save 25% of recommended nitrogen fertilizer but foliar fertilization with dap could not save nitrogen fertilizer applied in soil for getting comparable number of grains panicle−1 found in f0n100. similar trend has been reported by saleem et al. (2013) and khan et al. (2009). unfilled spikelets panicle−1 and thousand grain weight unfilled spikelets panicle−1 and thousand grain weight were not influenced significantly by foliar fertilization, nitrogen levels and the combined effect of foliar fertilization and nitrogen levels (table 5). 82 mohona et al. table 5. effect of foliar fertilization and nitrogen levels on unfilled spikelets panicle−1 and thousand grains weight of brri dhan28 treatment unfilled spikelet panicle−1 1000 grains weight (g) foliar fertilization f0 36.58 22.65 f1 37.69 22.30 f2 40.23 23.06 f3 36.54 22.14 significance level ns ns cv (%) 14.51 5.28 nitrogen levels n50 39.80 22.65 n75 38.02 22.67 n100 35.40 22.94 significance level ns ns cv (%) 18.21 4.14 foliar fertilization × nitrogen levels f0n50 34.06 22.57 f0n75 39.07 22.72 f0n100 36.60 22.47 f1n50 43.07 22.63 f1n75 37.54 22.51 f1n100 32.47 21.77 f2n50 46.73 22.41 f2n75 37.33 23.31 f2n100 36.63 23.47 f3n50 35.34 22.81 f3n75 38.14 22.15 f3n100 36.13 21.47 significance level ns ns cv (%) 18.21 4.14 in a column, means followed by different letter(s) within main and interaction effect differ significantly at p ≤ 5% level of probability grain yield hill−1 grain yield hill−1 was influenced significantly by foliar fertilization, nitrogen levels and the combined effect of foliar fertilization and nitrogen levels (table 6). among the treatment combinations, the maximum grain yield hill−1 was recorded in f3n100 (33.75 g) which was statistically similar to f1n100 (33.16 g) followed by f3n75, (31.15 g), f2n100 (30.89 g), f0n100 (30.13 g), and f1n75 (30.00 g). the lowest grain yield hill−1 was obtained from f0n50 (18.09 g) which was followed by f1n50 (20.90 g) and f2n50 (21.60 g). foliar fertilization with kno3 and american npks could save 25% of recommended nitrogen fertilizer but foliar fertilization with dap could not save nitrogen fertilizer applied in soil for getting equivalent number of grain yield hill−1 found in f0n100. similar results were also observed by pramanik et al. (2015) and rabin et al. (2016). table 6. effect of foliar fertilization and nitrogen levels on grain yield hill−1 of brri dhan28 foliar fertilization grain yield hill−1 (g) nitrogen levels mean of foliar fertilization n50 n75 n100 f0 18.09 f 24.80 d 30.13 b 24.34 d f1 20.90 e 30.00 b 33.16 a 28.02 b f2 21.60 e 26.16 cd 30.89 b 26.22 c f3 27.50 c 31.15 b 33.75 a 30.80 a mean of nitrogen levels 22.02 c 28.03 b 31.98 a cv (%) 2.42 level of significance ** foliar fertilization on brri dhan28 to reduce application of nitrogenous fertilizer 83 means followed by different capital letter(s) for main effect and small letter (s) for interaction differed significantly at p ≤ 5% level of probability by tukey’s test cv for foliar fertilization and nitrogen levels= 1.83% and 2.42% straw yield hill−1 straw yield hill−1 of brri dhan28 was not influenced significantly by foliar fertilization and the interaction effect of foliar fertilization and nitrogen levels but it was influenced significantly by nitrogen levels (fig. 1). fig. 1 shows that straw yield (g hill−1) was increased gradually with the increment of nitrogen level. the highest straw yield (25.33 g hill−1) was obtained when recommended nitrogen fertilizer was applied as urea (n100) which was statistically equal to that recorded in n75 (23.80 g hill−1). the lowest straw yield (19.15 g hill−1) was recorded in n50. saleem et al. (2013), pramanik et al. (2015) and rabin et al. (2016) also reported increase in nitrogen levels caused significant increase in straw yield in rice. similar trend has been reported by fageria et al. (2009), jagathjothi et al. (2012) and surya (2015). fig.1. effect of nitrogen levels (n50 = 50% of the recommended nitrogen fertilizer, n75 = 75% of the recommended nitrogen fertilizer and n100 = 100% of the recommended nitrogen fertilizer) on straw yield of brri dhan28. grain yield grain yield (t ha−1) was influenced significantly by foliar fertilization, nitrogen levels and the combined effect of foliar fertilization and nitrogen levels (table 7). among the treatment combinations, the maximum grain yield (t ha−1) was recorded in f3n100 (7.63 t ha−1) which was statistically similar to f1n100 (7.58 t ha−1) followed by f3n75, (7.00 t ha−1), f2n100 (6.95 t ha−1), f0n100 (6.78 t ha−1), and f1n75 (6.82 t ha−1). the lowest grain yield was obtained from f0n50 (4.07 t ha−1) which was followed by f2n50 (4.87 t ha−1) and f0n750 (5.42 t ha−1). foliar fertilization with kno3 and american npks could save 25% of recommended nitrogen fertilizer but foliar fertilization with dap could not save nitrogen fertilizer applied in soil for getting comparable grain yield found in f0n100. foliar fertilization of kno3 and american npks with recommended nitrogen fertilizer applied in soil could increase 11.8 and 12.5% grain yield, respectively compare to f0n100. similar trend has been reported by hasan et al. (2020), jothi et al. (2019), manik et al. (2016), pramanik et al. (2015) and saleem et al. (2013). table 7. effect of foliar fertilization and nitrogen levels on grain yield of brri dhan28 foliar fertilization grain yield (t ha−1) nitrogen levels mean of foliar fertilization n50 n75 n100 f0 4.07 f (40.0) 5.42 de (20.1) 6.78 c (0.0) 5.42 c f1 6.06 d (10.6) 6.82 c (+ 0.5) 7.58 ab (+ 11.8) 6.82 a f2 4.87 e (28.2) 5.91 d (12.8) 6.95 bc (+ 2.5) 5.91 b f3 5.67 d 7.00 bc 7.63 a 6.77 a 19.15 b 23.80 ab 25.33 a 0 5 10 15 20 25 30 n50 n75 n100 st ra w y ile d ( g h ill− 1 ) nitrogen levels 84 mohona et al. (16.4) (+ 3.2) (+ 12.5) mean of nitrogen levels 5.17 c 6.29 b 7.24 a cv (%) 3.03 level of significance ** means followed by different capital letter(s) for main effect and small letter (s) for interaction differed significantly at p ≤ 5% level of probability by tukey’s test, values in parenthesis indicates percent change over f0n100 conclusion foliar fertilization with kno3, dap (di-ammonium phosphate) and american npks significantly increased the grain yield (t ha−1) compare to control (f0) but kno3 and american npks performed better than dap. foliar fertilization with kno3 and american npks could save 25% of recommended nitrogen fertilizer but foliar fertilization with dap could not save nitrogen fertilizer applied in soil for getting comparable grain yield found in f0n100. foliar fertilization of kno3 and american npks with recommended nitrogen fertilizer applied in soil could increase 11.8% and 12.5% grain yield, respectively compare to f0n100. references ahmad, r. and r. jabeen. 2005. foliar spray of mineral elements antagonistic to sodiuma technique to induce salt tolerance in plant growing under saline condition. pak. j. bot. 37(4): 913-920. alam, s.s., a.z.m. moslehuddin, m.r. islam and a.m. kamal. 2010. soil and foliar application of nitrogen for boro rice (brri dhan 29). j. bangladesh agric. univ. 8(2): 199-202. ali, a., i.a. mohammed, f. hussain and m. salim. 2005. performance of rice as affected by foliar application of different k fertilizer sources. pak. j. agric. 42: 1-2. barc (bangladesh agricultural research council). 2018. fertilizer recommendation guide. barc, farmgate, dhaka. pp. 1-223. de datta, s.k. 1978. fertilizer management for efficient use in wetland rice soils. in: f.n. ponnamperuma (eds.). soils and rice. international rice research institute los banos, philippines. pp. 671-670. fageria, n.k., m.b.p. filho, a. moreira and c.m. guirmaraes. 2009. foliar fertilization of crop plants. j. plant nutr. 32(6): 1044-1064. finck, a. 1982. fertilizers and fertilization: introduction and practical guide to crop fertilization. verlag chimie gmbh, weinheim, germany. pp. 438. flinn, j.c., s.k. de datta and e. labadan. 1982. an analysis of long term rice yield in a wet land soil. field crops res. 5: 201-216. gomez, k.a. and a. a. gomez. 1984. statistical procedures for agricultural research, international rice research institute, john wiley and sons, new york. pp. 680. hasan, m., m.b. akter, m.m. karim, f. yasmine and a.k. hasan. 2020. response of potassium nitrate on yield and yield contributing characters of boro rice cv. brri dhan28. int. j. multidiscip. pers. 1(1): 5-13. hasewaga, p., r.a. bressan, j.k. zhu and h.j. bohnert. 2000. plant cellular and molecular responses to high salinity. annu. rev. plant mol. biol. 51: 463499. jagathjothi, n., p. muthukrishnan and m.m. amanullah. 2012. influence of foliar nutrition on growth and yield of transplanted rice. madras agric. j. 99(4-6): 275-278. jamal, z., m. hamayun, n. ahmad and m.f. chaudhary 2006. effect of soil and foliar application of different concentrations of npk and foliar application of (nh4)2so4 on different parameters in wheat. j. agron. 5(2): 251-256. kundu, c. and r.k. sarkar. 2009. effect of foliar application of potassium nitrate and calcium nitrate on performance of rainfed lowland rice (oryza sativa l.). indian j. agron. 54: 428-432. jothi, m., p. keerthana, s. gomathi, b. priya, t. ramesh and s. rathika. 2019. effect of foliar spray of potassium on rice under sodic soil. pharm. innov. 8(8): 244-247. khan, p., m.y. memon, m. imtiaz and m. aslam. 2009. response of wheat to foliar and soil application of urea at different growth stage. pak. j. bot. 41(3): 1197-1204. manik, i.h., m.a. abedin, m.r. rahman, t. chakrobarty, s.b. jaman, m.a. noor and r. sultana. 2016. reducing urea demand for rice crop through foliar application of urea in boro season. res. agric. livest. fish. 3(1): 79-85. mohan, a., a. tiwari, m. kumar, d. pandey, a. singh and b. singh. 2017. effect of foliar spray of various nutrients on performance of rainfed rice (oryza sativa l.). j. pharmacogn. phytochem. 6(5): 2252-2256. foliar fertilization on brri dhan28 to reduce application of nitrogenous fertilizer 85 pramanik, a.h.m.m., m.a. hasan, m.g. hossain and m.r. islam. 2015. foliar fertilization on brridhan28 to reduce soil application of nitrogenous fertilizer. j. sci. technol. 13: 64-74. rabin, m.h., m.a. razzaque, s.s. zamil, k. ashraf-uz-zaman and m.a. siddik. 2016. foliar application of urea and magic growth liquid fertilizer on the yield and nutrient content of aman rice cultivars. americaneurasian j. agric. & environ. sci. 16(4): 737-743. rani, s.b., g.t. krishna and p. munirathnam. 2014. studies on the effect of foliar fertilization in combination with conventional fertilizers on yield, economics and nutrient uptake of rice (oryza sativa l.) under k.c. canal ayacut area of andhra pradesh. indian agric. sci. digest. 34(1): 15-20. saleem, i., s. javid, r.a. sial, s. ehsan and z.a. ahmad. 2013. substitution of soil application of urea with foliar application to minimize the wheat yield losses. soil environ. 32(2): 141-145. shafiee, m.i., a.n. boycea, m.m. khandakera, j.m. saadb, t.a. aziz, m.s. mispana, m.s.m. arnuara and b.h. bakara. 2013. pilot studies on rice yield enhancement with foliar application of sbaja in sungai besar, selangor, malaysia. life sci. j. 10(1): 329-335. sharief, a.e., s.e. el-kalla, a.t. el-kassaby, m.h. ghonema and g.m.q. abdo. 2006. effect of biochemical fertilization and times of nutrient foliar application on growth, yield and yield components of rice. j. agron. 5(2): 212-219. shayganya, j., n. peivandy and s. ghasemi. 2011. increased yield of direct seeded rice (oryza sativa l.) by foliar fertilization through multicomponent fertilizers. arch. agron. soil sci. 58(10): 1091–1098. surya, m.s. 2015. flag leaf nutrition for enhancing resource use efficiency in rice (oryza sativa l.). m.sc. thesis. kerala agricultural university, thrissur. swaroopa, v.j. and m.b. lakshmi. 2015. effect of nitrogen and foliar fertilization on yield components and quality parameters of machine transplanted rice. curr. biotica. 9(3): 230-238. bangladesh agron. j. 2023, 26(1): 112-121 effect of fertilizer on the growth and yield of boro and t. aman rice in the soils of industrially polluted agricultural land areas of madhupur tract m.n huda1, s.m. masum2, m.o.a mollick3 and m.a. khan3* 1deputy director, external service, bangladesh betar, sher-e-bangla nagar, dhaka-1207, bangladesh 2department of agronomy, sher-e-bangla agricultural university, dhaka-1207,bangladesh 3department of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: makhan@sau.edu.bd (received: 22 august 2023, accepted: 20 september 2023) keywords: industrial pollution, fertilizer, boro rice, t. aman rice, yield abstract a pot experiment was conducted during 2018-19 in a net house at the department of soil science, sher-e-bangla agricultural university, dhaka, to determine fertilizer's effect on the growth and yield of boro and t. aman rice in the soils of industrially polluted agricultural land areas of madhupur tract. the study consisted of two factors, i.e., polluted soil viz., s1: nonpolluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3, and four fertilizer treatments viz., t0: control, t1: n150p30k60s20zn3.0 (100%rdcf), t2: n105p21k42s14zn2.1 (70%rdcf) t3: n75p15k30s10zn1.5(50%rdcf) the experiment was laid out in a randomized complete block design (rcbd) with three replications. among the soils, the highest boro rice grain yield of 90.83 g pot-1 was found in s2 (polluted soil-1) soil, and the lowest 41.66 g pot-1 in soil s1 (non-polluted soil). the treatment t3(50% rdcf) fertilizer treatment gave the highest plant height (84.12 cm), effective tillers (42.5 hill–1), straw (112.58g pot –1) and grain yield (80.03g pot−1) of boro rice. the higher grain and straw yields of boro rice were obtained from two industrially polluted soils (s2 and s4). the maximum grain yield (112.3g pot–1) of boro was found in s2t3 (contaminated soil 1 and 50% rdcf) , which was statistically similar to s4t2 and s4t3 and lowest in the s1t0 treatment combination. the maximum t. aman grain yield (38.75gpot−1) was obtained in soil s2 (polluted soil-1), which at par to s4 (polluted soil-3). the maximum t. aman rice grain yield (36.68 g pot−1) was found in the t2 treatment, which was closely by t1 treatment. similarly, the maximum t. aman grain yield was obtained in s2t1 (contaminated soil 1 and 100% rdcf) which was statistically similar to s2t2, s4t1, and s4t2 and lowest in the s1t0 treatment combination. the highest t. aman straw yield was found in the s3t1 and lowest in the s1t0 treatment combination. introduction generally, industrial effluents contain several metals which are harmful to plants as well as animals. the effluents generated by textile industries contribute a substantial share of contaminants for pollution of the disposal areas. this problem is most severe in developing countries like bangladesh. the situation in bangladesh is too worse because of poor management and disposal of industrial effluents. improper management and disposal of industrial effluents may cause tremendous negative impacts to our water, soil, crops, aquatic and wildlife, human, biodiversity, and environment. there is a rapid establishment of textile and dyeing industries in many areas of bangladesh. bhaluka is one of the commercially important areas where industrial clusters have developed as part of the country's rapid economic growth. although poultry farms, pharmaceutical industries, and a tannery have been established there, textile manufacturers, including dyeing and effect of fertilizer on the growth and yield of rice 113 printing units, dominate the area (chowdhury and clemett, 2006). these industries provide employment, increase local incomes, and earn foreign exchange. but these industries have brought a range of problems, including serious environmental pollution. these industries discharge untreated effluents into the ecosystem, which local people depend on for their livelihoods. industrial effluents contain appreciable amounts of trace metals, which may accumulate in the soil, thus creating a problem for the safe and rational utilization of agricultural soils (chen et al., 2005). industrial wastewater contains various toxic materials. at low concentrations, some trace elements (e.g., cu, mn, ni, se, and zn, etc.) are essential for the healthy functioning and reproduction of microorganisms, plants, and animals, including man. however, at high concentrations, the same essential elements may pose toxicity. trace elements are present naturally in the soil.moreover, textile effluent is recognized as the top-ranked pollutant among all industrial sectors considering effluents' volume and composition (vanndevivera et al., 1998; roy et al., 2010). the disposal of textile effluents in crop fields decreased rice production which was responsible for environmental degradation (setyorini et al., 2002). usually, industrial effluents contain specific chemicals which pollute different water bodies and damages aquatic ecosystem (moeller and dade, 1992; benard and wright, 1998). it was also reported that industrial effluents were not encouraged for irrigation due to health hazards, which may harm crops and crop consumers (ogedngbe and akinbile, 2010). disposal of textile effluents to crop fields decreased rice production and was responsible for environmental degradation (setyorini et al., 2002). most industries in bangladesh seldom pass the effluent through water treatment plants; as a result, untreated industrial effluent floods the land, mostly rice fields surrounding the industries. large amounts of external nutrient inputs in soil through industrial effluent and the unscientific use of fertilizers have contributed to low n and p use efficiency, resulting in serious soil degradation, eutrophication, groundwater pollution and the emission of ammonia and greenhouse gases (qi et al. 2020). the information’s on crops grown in the industrially polluted soils of bangladesh and appropriate fertilizer management is still lacking. therefore, the study evaluated rice growth and yield in industrially polluted soils and assessed the effect of fertilizer management on the growth and yield of rice in industrially contaminated soils. materials and methods the experiment was conducted at sher-e-bangla agricultural university net house from december 2018 to november 2019. the industrially polluted soils of the experiment belong to the aez no. 28, madhupur tract, in bangladesh. the experiment was laid out in randomized complete block design with three replications. considering the soil pollution intensity, four different soils were collected from bhaluka industrially polluted rice growing areas. the soil texture, ph, % oc, and metal concentrations are mentioned in table 1. there were 48 pots (4 fertilizer treatments x 4 industrially polluted soils x 3 replications) altogether, and 17 kg of soil was taken in each pot. the fertilizer treatments were used in this experiment based on barc fertilizer recommendation guide, 2018. the required amount of inorganic fertilizers was used in this rice experiment. the initial soil samples were dried, powdered in a mill, and analyzed for nutrient content and physicochemical properties following standard methods. there were four fertilizer treatments, namely t0: control, t1: n150p30k60s20zn3.0 (100% rdcf), t2: n105p21k42s14zn2.1 (70% rdcf) t3: n75p15k30s10zn1.5 (50% rdcf) in combination with 4 soils (s1: non-polluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3). traditional irrigation i.e., continuous flooding (2-3 cm water) was imposed during boro and t. aman rice growing period high-yielding popular rice var. brri dhan29 was used for boro rice. treatment-wise, required 114 m.a.khan et al. amounts of fertilizer were applied to both crops boro and t. aman rice. the required amount of tsp, mop, gypsum, zinc sulphate, and one third urea was applied during the final pot preparation by considering the fertilizer treatments and weight of pot soil. the fertilizers were uniformly mixed in the soils of the pot. the first crop var. brri dhan29 was transplanted in the first week of january 2019. two seedlings were transplanted in each pot to make one hill, and intercultural operations were done as required. the crop was harvested at maturity on may 2019. the grains were separated from straw and filled and unfilled grains counted. the weights of grain and straw were recorded after drying. after the harvest of boro rice, the t. aman rice (var. brri dhan33) was grown in the same pots to find out the residual effects of applied fertilizer to the previous crop (boro rice) and newly treatment wise added fertilizer for t. aman rice. the lower amounts of fertilizer were applied during t. aman rice grows according to the recommended dose of chemical fertilizer (n120p20k60s10zn1.5). the data of yield parameters and yields were recorded. after harvesting t. aman rice, the yield and yield parameters were recorded. the data were analyzed with mstat-c. the initial soils were analyzed for soil organic matter, ph, total cd, pb, and zn. soil ph was measured by a glass electrode ph meter using a soil-water ratio of 1:2:5 (mclean, 1982). organic matter content was estimated by the wet oxidation method (nelson and sommers, 1982). the cd, pb, and zn concentrations in soil samples were determined by an atomic absorption spectrophotometer (model: novaa400p, brand: analytic jena) (scott et al., 1991) (table 1). for the determination of total cd, pb, and zn concentrations, soil samples were digested using hno3 and hclo4 and concentrations were determined by flame atomic absorption spectrophotometry. the higher levels of organic carbon, cd and pb were observed in the industrially polluted soils than non-polluted soils. the statistical analysis and the means were separated using duncans multiple range test as per gomez and gomez (1984). table 1. the physicochemical properties and cd, pb, and zn concentrations in industrially polluted initial soils soils cd conc. (ppm) pb conc. (ppm) zn conc. (ppm) ph % oc soil texture s1(non-polluted soils of industrial area) 0.52 1.91 59.0 6.4 0.76 silt loam s2(industrially polluted soil-1) 3.48 5.81 61.0 6.5 0.92 silt loam s3(industrially polluted soil-2) 3.68 6.03 64.0 6.4 1.03 silt loam s4(industrially polluted soil-3) 4.09 6.21 59.5 6.5 0.98 silt loam results and discussion effect of soil on the growth, yield parameters, and yield of boro rice the polluted soils significantly influenced the boro rice yield parameters and straw yields (table 2). the higher number of effective tillers hill-1 and panicle length were noticed in s3 (polluted soil-2). the higher plant height, number of filled grains panicle−1, thousand seed weight, and grain yield (g pot−1) were found in s2 (polluted soil-1), and lower values of the following yield parameters and yields were found in the non-polluted soil (s-1) (table 2). the highest number of unfilled grains panicle−1 was obtained in s3 (polluted soil-2) soil, this result indicates that grain unfilling increased due to industrial soil pollution. the maximum grain yield (90.83 g pot−1) was found in s2 (polluted soil-1), which was statistically similar to s4 (polluted soil-3), and the lowest 67.87 g pot−1 in the s1 (non-polluted soil). the highest straw yield (117.67 g pot−1) was obtained in s4 (polluted soileffect of fertilizer on the growth and yield of rice 115 3), which was statistically similar to s2 (polluted soil-1) and s3 (polluted soil-2) soils and the lowest straw yield in the soil s1 (non-polluted soil). the higher and statistically similar grain and straw yields were obtained from three industrially polluted soils (s2, s3, and s4). table 2. effect of soil on growth, yield contributing parameters, and yield of boro rice treatment effective tiller hill−1 noneffective tillers hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grain 1000grain wt. (g) straw yield (g) grain yield (g) s1 22.00c 2.92b 72.37c 23.74c 122.2a 35.5c 21.17ab 48.00b 41.658c s2 39.58b 3.92b 88.71a 26.95ab 136.0a 32.2c 22.00a 111.08a 90.825a s3 47.50a 5.92a 83.65b 27.30a 104.7b 75.7a 20.42b 112.17a 69.558b s4 39.33b 6.25a 84.12ab 26.15b 132.8a 44.4b 20.75ab 117.67a 90.525a se± 1.62 0.24 1.10 0.22 3.48 1.93 0.30 2.77 2.52 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here,s1: non-polluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3 effects of fertilizer on the growth, yield parameters, and yield of boro rice different fertilizer treatments significantly affected the plant height, panicle length, effective tillers hill−1, filled grains panicle−1, 1000-grain weight, and grain and straw yields (g pot1) (table 3). table 3. effect of fertilizer on growth, yield contributing parameters, and yield of boro rice treatment effective tiller hill−1 noneffective tiller hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grain 1000 grain wt. (g) straw yield (g) grain yield (g) t0 28.25b 4.58b 78.50b 25.63 117.0a 43.8b 21.50 71.83c 63.058b t1 40.67a 6.42a 82.58ab 26.41 131.1a 54.4a 21.33 99.67b 73.575ab t2 37.00a 3.67b 84.96a 25.80 120.9a 43.5b 20.92 104.83ab 75.908a t3 42.50a 4.33b 82.82ab 26.30 126.7a 46.0ab 20.58 112.58a 80.025a se 1.62 0.24 1.10 0.22 3.48 1.93 0.30 2.77 2.52 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, t0: control, t1: n150p30k60s20zn3.0 (100%rdcf), t2: n105p21k42s14zn2.1 (70%rdcf) t3: n75p15k30s10zn1.5 (50%rdcf) the higher number of non-effective tillers pot−1 (6.42), filled grains panicle−1 (131.1), unfilled grains panicle−1 (54.4), and panicle length (26.41 cm) were found in the t1 treatment where 100% rdcf was applied. the treatment t2 (70 % rdcf) fertilizer gave the maximum plant height (84.96 cm) which was, statistically similar to all other treatments except the control. the maximum number of effective tillers hill−1 (42.50), straw (112.58g pot−1), and grain yield (80.03g pot−1) were obtained in fertilizer treatment t3 (50% rdcf), which was statistically similar to t2 (70 % rdcf) and t1 (100 % rdcf) treatments. the results indicate that application of lower levels of fertilizer (50% rdcf or 70% rdcf) performed better for increasing boro rice yield in industrially polluted soils may be due to higher organic matter, nutrient, beneficial and toxic elements supplying capacity of industrially polluted soils. 116 m.a.khan et al. continuous use effluents in the industrially polluted soils for rice production could result in accumulation elements in the concentrations (ghafoor et al., 1999). polluted soils can supply more n, p and k and also valuable micronutrients than what crops require (panicker, 1995) and crops gave higher yields in this study where 50% rdcf or 70 % rdcf were applied. interaction effects of fertilizer and manure on the growth, yield parameters, and yield of boro rice the plant height, panicle length, effective tillers hill−1, filled grains panicle-1, unfilled grains panicle−1, and grain and straw yields of boro rice were significantly influenced by the interaction effects of soil and fertilizer treatments (table 4). the maximum number of effective tillers hill−1 (47.33) was found in s3t3 (polluted soil 2 and 50% rdcf) , which was statistically similar to s4t2, s4t1, s3t2, s3t1, s2t3, and s2t1 treatment combinations. all industrially polluted soils produced a higher number of tillers than non-polluted soils with different fertilizer treatments. the maximum plant height (91.47cm) was noticed in the s2t2 , which was statistically and closely similar to s2t1, s2t3, s3t2, s3t3, s4t1, s4t2, and s4t3 treatment combinations. similar to the number of effective tillers hill-1, all industrially polluted soils produced higher plant height than non-polluted soils with different fertilizer treatments. table 4. effects soil and fertilizer on growth, yield contributing parameters, and yield of boro rice in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here,s1: non-polluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3; , t0: control, t1: n150p30k60s20zn3.0 (100%rdcf), t2: n105p21k42s14zn2.1 (70%rdcf) t3: n75p15k30s10zn1.5 (50%rdcf) similarly, the maximum panicle length (27.83cm) was obtained in s3t3 (polluted soil 2 and 50% rdcf) treatment combination, which was statistically similar to s3t2, s3t1, s2t1, s2t2, treatments effective tiller hill−1 noneffective tiller hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grains panicle−1 1000grain wt. (g) straw yield (g) grain yield (g) s1×t0 16.67f 2.67 71.23ef 23.47fg 104.4ef 32.5f 22.33 36.33g 31.00 f s1×t1 26.33ef 4.33 75.87d-f 24.93def 161.8a 28.9f 20.67 66.33 f 63.63e s1×t2 18.67f 2.33 72.21d-f 22.33g 102.7ef 34.6ef 21.00 42.00g 38.93f s1×t3 26.33ef 2.33 70.17f 24.21ef 120.0c-e 46.1de 20.67 47.33g 33.07f s2×t0 33.00de 3.67 85.20a-c 26.40a-d 118.7c-e 33.3ef 22.33 78.33def 72.17de s2×t1 45.33abc 5.33 90.20a 27.20ab 135.3bc 32.5f 22.67 142.00ab 104.60a s2×t2 32.67de 3.67 91.47a 27.23ab 145.1ab 33.5ef 21.67 92.67de 74.23de s2×t3 47.33a-c 3.00 87.97a 26.97ab 144.9ab 29.5f 21.33 131.33bc 112.30a s3×t0 38.33cd 5.67 79.43b-d 27.47ab 119.7c-e 77.2b 20.00 96.67d 85.60cd s3×t1 46.33a-c 8.00 76.73d-f 26.73a-c 89.1f 91.1a 20.67 40.33g 30.53f s3×t2 50.33ab 4.33 89.58a 27.18ab 106.4d-f 56.9cd 20.67 159.33a 86.87bd s3×t3 55.00a 5.67 88.87a 27.83a 103.7ef 77.5b 20.33 152.33a 75.23de s4×t0 25.00ef 6.33 78.14c-e 25.20c-e 125.3b-e 32.3f 21.33 76.00ef 63.47e s4×t1 44.67a-c 8.00 87.51a 26.77ab 138.1a-c 65.1bc 21.33 150.00a 95.53a-c s4×t2 46.33a-c 4.33 86.57ab 26.47a-d 129.5b-d 49.1d 20.33 125.33bc 103.60a b s4×t3 41.33b-d 6.33 84.27a-c 26.17b-d 138.3a-c 30.9f 20.00 119.33c 99.50a-c se± 3.24 0.48 2.19 0.44 6.95 3.85 0.61 5.55 5.03 cv(%) 15.14 17.42 4.62 2.95 9.72 14.21 4.98 9.88 11.93 effect of fertilizer on the growth and yield of rice 117 s2t3, s4t1, and s4t2 treatment combinations. the highest grains panicle−1 (161.8) was obtained in s1t1 (non-polluted soil and 100% rdcf), which was statistically comparable to s4t1, s2t2, s2t3 and s4t1 treatment combinations, and it indicates that the numbers of filled grains panicle−1 were increased in non-polluted soils. the highest number of unfilled grains panicle−1 (91.1) and non-effective tillers hill−1 were obtained in s3t1 and s4t1 treatment combinations, and it proves that the application of higher amounts of fertilizers in polluted soils increases the number of noneffective tillers and unfilled grains panicle−1. the highest straw yield (159.3 g pot−1) was found in s3t2 (contaminated soil 2 and 70% rdcf) , which was statistically similar to s2t1, s3t3, and s4t1 and lowest in s1t0 treatment combination. the maximum grain yield (112.30 g pot−1) was found in s2t3 (contaminated soil 1 and 50% rdcf) which was statistically comparable to s2t1, s4t1, s4t2, and s4t3 and lowest in s1t0 treatment combination. the higher boro rice yields were obtained in industrially polluted soils with different fertilizer treatments compared to non-polluted soil s1. these results indicate that applying lower levels of inorganic fertilizers on polluted soils increased the grain and straw yields of boro rice, and 70 or 50% recommended dose of chemical fertilizer performed better in different industrially polluted soils. the increase in organic matter and nitrogen after wastewater addition would be beneficial for soil fertility. many investigations, including long and short-term studies, showed that soil fertility increases as a consequence of the application of wastes (bernal et al., 1993; chakrabarti, 1995) in industrially polluted soils and this findings support the results of the present experiment where higher yields were obtained in industrially polluted soils by using 70 or 50% recommended dose of chemical fertilizer. effects of soil on the growth, yield parameters, and yield of t. aman rice the plant height, panicle length, effective tillers hill−1, non-effective tillers hill−1, filled grains panicle−1, grain and straw yield of t. aman rice were affected by different soils (table 5). table 5. effect of soil on growth, yield parameters, grain and straw yield of t. aman rice treatment effective tiller number hill−1 noneffective tiller number hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grain panicle−1 straw yield (g) grain yield (g) s1 14.83c 1.33ab 101.36 24.38a 96.33a 37.35d 27.53b 21.60b s2 24.00b 1.42ab 101.83 24.09ab 86.02b 50.27c 53.93a 38.75a s3 29.50a 1.00b 99.13 22.86b 42.85c 69.99a 54.19a 23.28b s4 24.50b 1.58a 99.77 24.11ab 83.09b 61.86b 47.48a 37.00a se 0.43 0.11 1.32 0.32 1.75 1.53 1.56 1.14 in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability ,here,s1: non-polluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3, the highest panicle length (24.38 cm) and filled grains panicle−1(96.33) were found in soil-1 (non-polluted soil). the highest number of effective tillers hill−1(29.50), un-filled grain panicle−1 (69.99) and straw yields (54.19 g pot−1) were found in soil s3 (polluted soil 2). the highest plant height (101.83 cm) and grain yield (38.75 g pot−1) were obtained in soil s2 (polluted soil-1), and the highest grain yield was closely and statistically similar to the grain yield of soil s4 (polluted soil 3). like boro rice, the higher grain yields were found in industrially polluted soils. 118 m.a.khan et al. effects of fertilizer on the growth, yield parameters, and yield of t. aman rice the plant height, panicle length, effective tillers hill−1, non-effective tillers hill−1, filled grains panicle−1, and grain and straw yields (g pot−1) were affected by different fertilizer treatments. the higher number of filled grains panicle−1(97.26) and straw yield were noticed in t1 (100% rdcf) treatment. the highest straw yield (52.57 g pot−1) was statistically similar to all other fertilizer treatments except the control. the significantly different and the highest panicle length (24.82 cm), number of effective tillers hill-1 (25.83), and grain yield (36.68 g pot-1) were found in t2 treatment where 70% rdcf was used. the highest grain yield was statistically similar to the t1 treatment (100% rdcf), and the lowest yield in the t0 treatment. the single effect of fertilizer treatments shows that t2 (70% rdcf) was suitable for industrially polluted soils. table 6. effect of fertilizer on growth, yield parameters, and yield of t. aman rice in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here, t0: control, t1: n150p30k60s20zn3.0 (100%rdcf), t2: n105p21k42s14zn2.1 (70%rdcf) t3: n75p15k30s10zn1.5 (50%rdcf) interaction effects of soil and fertilizer on the growth, yield parameters and yield of t. aman rice the plant height, panicle length, effective tillers hill−1, filled grains panicle−1, unfilled grains panicle−1, and grain and straw yields were significantly influenced by the interaction effects of soil and fertilizer treatments (table 7). the maximum number of effective tillers hill-1 (33.0) was found in the s3t2 , which was statistically similar to the s3t1 , and the highest plant height (116.47 cm) was observed in the s2t1 treatment combination.the highest panicle length (25.73 cm) and grain yield were obtained in s2t1 (contaminated soil 1 and 100% rdcf) treatment combination. the maximum number of filled grains panicle-1(112.6) was recorded in s1t1 (non-polluted soil and 100% rdcf), which was statistically comparable to s1t2, s1t3, s2t1, and s4t1, and the lowest in s1t0 treatment combinations. the highest number of unfilled grains panicle−1 (73.73) was observed in s3t3 (polluted soil 2 and 50% rdcf) treatment combination, which was statistically comparable to s2t3, s3t0, s3t1, s3t2, s4t0 and s4t1 treatment combinations and lowest unfilled grains panicle-1 in s1t1 . similarly, the highest number of non-effective tillers hill−1 (2.0) was recorded in the s2t3 and lowest in the s1t1 treatment combination. treatment effective tiller hill−1 noneffective tiller hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grain panicle−1 straw yield (g) grain yield (g) t0 17.50b 1.17 96.56b 22.48b 57.53c 58.09a 31.17b 17.86c t1 24.92a 1.17 107.02a 24.35a 97.26a 47.68b 52.87a 36.63a t2 25.83a 1.50 101.70ab 24.82a 79.98b 55.55a 51.76a 36.68a t3 24.58a 1.50 96.82b 23.79ab 73.52b 58.15a 47.33a 29.47b se 0.43 0.11 1.32 0.32 1.75 1.53 1.56 1.14 effect of fertilizer on the growth and yield of rice 119 table 7. interaction effect of soil and fertilizer on growth, yield parameters, and yield of t. aman rice in a column means having a similar letter(s) are statistically similar and those having a dissimilar letter(s) differ significantly at a 0.05 level of probability here,s1: non-polluted soil, s2: polluted soil-1, s3: polluted soil-2, s4: polluted soil-3; , t0: control, t1: n150p30k60s20zn3.0 (100%rdcf), t2: n105p21k42s14zn2.1 (70%rdcf) t3: n75p15k30s10zn1.5 (50%rdcf) these results indicated that industrially polluted soils gave more non-effective tillers hill-1 and unfilled grains panicle−1 with different fertilizer treatments. the highest straw (63.83 g pot-1) yield was found in the s3t1 treatment and the lowest in the s1t0 treatment combination. similar to boro rice, higher grain yields were recorded in industrially polluted soils with different fertilizer treatments. the highest grain yield (50.37 g pot−1) was found i, which was statistically similar to s2t2, s4t1, and s4t2 and lowest in the s1t0 treatment combination. the waste water addition may increase soil fertility. many investigations, showed that soil fertility increases as a consequence of the application of industrial wastes (hart and speir, 1992; navas et al., 1998) and similar findings were obtained in the present study where higher yields were obtained in industrially polluted soils in comparison to non-polluted soil s-1 conclusion boro and t. aman rice yield parameters and yields varied with polluted soils and fertilizer treatments. the higher yields of boro and t. aman rice were obtained in three industrially polluted soils compared to one non-polluted soil of the same industrial areas of bhaluka. the highest boro treatment effective tiller hill−1 noneffective tiller hill−1 plant height (cm) panicle length (cm) filled grains panicle−1 un-filled grain panicle−1 straw yield (g) grain yield (g) s1×t0 9.67h 1.00b 90.70ef 21.37e 49.80f 52.67e 13.80 8.60f s1×t1 16.00g 1.00b 103.00bc 23.70b-d 112.60ab 24.53g 32.90 23.87de s1×t2 16.67fg 1.67ab 105.53b 27.73a 120.13a 36.00f 31.57 27.90cd s1×t3 17.00fg 1.67ab 106.20b 24.70bc 102.80b 36.20f 31.83 26.03cd s2×t0 19.00f 1.00b 102.40b-d 22.03de 61.93e 49.67e 43.43 25.50d s2×t1 24.67de 1.00b 116.47a 25.73ab 122.33a 30.27fg 57.07 50.37a s2×t2 27.33cd 1.67ab 104.00bc 24.43bc 86.93c 54.73de 62.77 45.60a s2×t3 25.00de 2.00a 84.47f 24.17b-d 72.87de 66.40a-c 52.47 33.53bc s3×t0 23.00e 1.00b 93.40de 23.30c-e 42.40f 65.00a-d 38.97 20.57de s3×t1 32.33ab 1.00b 102.93bc 23.26c-e 49.32f 69.70ab 63.83 24.40de s3×t2 33.00a 1.00b 101.20b-d 22.09de 39.60f 71.53a 59.20 26.80cd s3×t3 29.67bc 1.00b 99.00b-e 22.80c-e 40.07f 73.73a 54.77 21.37de s4×t0 18.33fg 1.67ab 99.73b-e 23.23c-e 75.97cd 65.03a-d 54.77 16.77e s4×t1 26.67d 1.67ab 105.67b 24.70bc 104.80b 66.20a-c 57.67 47.87a s4×t2 26.33d 1.67ab 96.07c-e 25.00bc 73.27de 59.93b-e 53.50 46.43a s4×t3 26.67d 1.33ab 97.60b-e 23.50b-e 78.33cd 56.27c-e 50.27 36.93b se 0.85 0.22 2.63 0.64 3.50 3.07 3.12 2.27 cv (%) 6.36 19.05 4.53 4.67 7.87 9.69 11.82 13.05 120 m.a.khan et al. and t. aman rice yields were found in polluted soil-1 and the lowest in non-polluted soil. the single effect of fertilizer treatment t1 (100% rdcf) performed better in non-polluted soil (s1), but the application of reduced levels of fertilizer treatments70% rdcf and 50% rdcf performed better in polluted soils for increasing the yield of boro and t. aman rice. the higher number of tillers hill-1, non-effective tillers hill-1, plant height, panicle length, unfilled grains panicle-1, grain and straw yields were found in three polluted soils compared to one non-polluted soil with different fertilizer treatments. the highest boro and t. aman rice grain yield were found in the contaminated soil-1 and 50% rdcf and contaminated soil-1 and 100% rdcf treatment combinations, respectively, and the lowest in the control treatment combination. the highest t. aman rice yield in the combination of contaminated soil-1 and 100% rdcf was closely similar to the combination of contaminated soil-3 and 70% rdcf and the combination of contaminated soil-3 and 70% rdcf treatment combinations. similarly, the higher yields of boro and t. aman rice were observed in three polluted soils with different fertilizer treatments. the application of reduced amounts of fertilizer treatments 50% rdcf or 70%rdcf could be suggested for industrially polluted soils of bhaluka areas. acknowledgment the authors gratefully acknowledges the special allocation project for the year 20182019[b.s-40] for financial support of the ministry of science and technology, bangladesh to conduct this research. references barc (bangladesh agricultural research council). 2018. fertilizer recommendation guide. barc, farmgate, dhaka, bangladesh. benard, j. and t. w. wright. 1998. environmental science (the way the world work) 6th end. prentice mall. new jersey. bernal, m.p., a. roig and d. garcia. 1993. nutrient balances in calcereous soils after application of different rates of pig slurry. soil use manag. 9: 9-14. chakrabarti, c. 1995. residual effects of long-term land application of domestic wastewater. environ. int. 21: 333-339. chen, y., c. wang and z. wang. 2005. residues and sources identification of persistent organic pollutants in farmland soils irrigated by effluents from biological treatment plants. environ. int. 31: 778-783. chowdhury, n.s. and a.e.v. clemett. 2006. industrial pollution and its threat to mokesh beel wetland in kaliakoir. mach technical report, dhaka, bangladesh. ghafoor, a., s. ahmad, m. qadir, s. i. hussain and murtaza, (1999). formation and leaching of lead species from a sandy loam alluvial soil as related to ph and cl:so4 ratio of leachates. j. agric. res., 30: 391-401. gomez, k. a. and gomez, a. a. 1984. statistical procedures for agricultural research. jhon wiley and sons, new york. hart, p.b.s. and t.w. speir. 1992. agricultural and industrial effluents and wastes as fertilizers and soil amendments in new zealand. in:the use of wastes and byproducts as fertilizers and soil amendments for pastures and crops. p.e.h. gregg, and l.d. currie (eds.). occasional report no.6. fertilizer and lime research centre. massey university. palmerston north, nz. pp.69-90. mclean, e. o. 1982. soil ph and lime requirement. in: methods of soil analysis, part 2, chemical and microbiological properties, a.l.page (eds.). american society of agronomy inc. madison, wi, usa. pp.199-224. moeller and w. dade.1992. toxic chemicals, in: environmental health. usa, 2 p. effect of fertilizer on the growth and yield of rice 121 navas, a., f. bermudez, and j. machin. 1998. influence of sewage sludge application on physical and chemical properties of gypsisols. geoderma 87: 123-135. nelson d.w. and sommers l.e. 1982. total organic carbon and organic matter. page, et al. (eds.), methods of soil analysis. part 2 (second ed.), american society of agronomy, madison, wi (1982), pp. 539577. ogedengbe, k. and c.o. akinbile. 2010. comparative analysis of the impact and agricultural effluent on ona stream in ibadan, nigeria. n. y. sci. j. 3(7): 25-33. panicker, p. v. r. c. 1995. recycling of human waste in agriculture. in: tandon, hls(ed.), recycling of waste in agriculture. fert. dev. consultation org., new delhi, india, p 68-90. roy, r., a. n. m. fakhruddin, r. khatun and m. s. islam. 2010. reduction of cod and ph of textile industrial effluents by aquatic macrophytes and algae. j. bangladesh academy sci. 34(1): 9-14. roy, r., a.n. m. fakhruddin, r. khatun, m. s. islam, m.a. ahsan and a.j.m.t. neger. 2010. characterization of textile industrial effluents and its effects on aquatic macrophytes and algae. bangladesh j. sci. ind. res. 45(1), 7984. scott, r.o., r.l. mitchell, d. purves and r.c. voss. 1991. spectrochemical methods for the analyses of soils, plants and other agricultural materials. consultative committee for development of spectrochemical work, bulletin no. 2 (1971). the macaulay inst. for soil research, aberdeen , 8. setyorini, d., t. prihatini and u. kurnia. 2002. pollution of soil by agricultural and industrial waste. food and fertilizer technology center, indonesia. url: http://www.agnet.org/library/eb/521/dated09 feb20101 qi, d., j. yan and j. zhu. 2020. effect of a reduced fertilizer rate on the water quality of paddy fields and rice yields under fishpond effluent irrigation. agril. water manag. vol. 231 article 105967. vanndevivera, p.c., r. bianchi and w. verstraete. 1998. treatment and reuse of wastewater from the textile wet-processing industry: review of emerging technologies. j. chem. technol. biotechnol. 72:289302. bangladesh agron. j. 2022, 25(1): 75-82 effect of planting system on productivity of hybrid maize-indian spinach intercropping system a.a. begum, m.h rahman, j. hossain, s.s. kakon, m.z. ali and d.a. choudhury agronomy division, bangladesh agricultural research institute, gazipur 1701 corresponding e-mail: luckyshamol6869@gmail.com (received: 15 may 2022, accepted: 02 august 2022) keywords: par interception, ler, yield, equivalent yield and bcr abstract a field experiment was undertaken at joydebpur, jashore and ishurdi farm of bangladesh agricultural research institute during kharif seasons of 2016 and 2017 to find out suitable combination of hybrid maize and indian spinach as intercropping system for higher productivity and monetary advantage. treatments included in the experiment were: t1 = hybrid maize normal row (75 cm  20 cm ) + 1 row indian spinach (plant to plant 25 cm), t2 = hybrid maize paired row (37.5 cm/150 cm  20 cm) + 1 row indian spinach (plant to plant 25 cm), t3 = hybrid maize paired row (37.5 cm/150 cm  20 cm) + 2 rows indian spinach (plant to plant 25 cm), t4 = hybrid maize paired row (37.5 cm/150 cm  20 cm) + 3 rows indian spinach (plant to plant 25 cm), t5 = sole maize (75 cm  20 cm) and t6 = sole indian spinach (40 cm  25 cm). grain yield of maize was the maximum in sole crop but it was decreased 1.0 to 12.6% at joydebpur, 5.2 to 17.1% at jashore and 13.4 to 22.2% at ishurdi due to inter specific competition for growth resources among maize and indian spinach due to intercropping. all intercropping treatments showed better performance than sole maize crop. the highest maize equivalent yield (19.22 and 18.80 t ha-1 at joydebpur, 13.30 and 11.58 t ha-1 at jashore and 11.23 and 11.10 t ha-1 at ishurdi in 2016 and 2017, respectively), gross margin (tk. 196300 and tk. 192000 ha-1 at joydebpur, tk. 111130 and tk. 85330 ha-1 at jashore and tk. 88450 and tk. 86500 ha-1 at ishurdi in 2016 and 2017, respectively) and benefit cost ratio (3.13 and 3.07 at joydebpur, 2.26 and 1.97 at jashore and 2.11 and 2.08 at ishurdi in 2016 and 2017, respectively) were observed in hybrid maize paired row + 3 rows indian spinach intercropping. the highest land equivalent ratio (1.32 and 1.39 at joydebpur and 1.50 and 1.47 at jashore in 2016 and 2017, respectively) was also found in the same treatment. on the other hand, at ishurdi, the highest ler (1.34 and 1.35 in 2016 and 2017, respectively) was observed in mnr + 1 rows isp treatment followed by mpr + 3 rows isp treatment. the results revealed that hybrid maize paired row + 3 rows indian spinach and hybrid maize normal row + 1 row indian spinach intercropping might be economically profitable for hybrid maize + indian spinach intercropping system at joydebpur, jashore and ishurdi. introduction intercropping is an important tool for getting higher productivity per unit area of land (mahfuza et al., 2012). maize is ideal for intercropping and mixed cropping, especially with legumes, potato, onion, groundnuts and vegetables. maize based intercropping is found profitable and suitable in many countries like bangladesh. hybrid maize is a unique crop because of its versatile use and low cost unit-1 production. maize grains and cobs can be used as food for human, poultry, livestock and fish. it can also be used as raw materials of varieties of industrial products (corn starch). so, there is ample scope for expansion of maize in bangladesh (islam and kaul, 1986). on the other hand, indian spinach (basella alba) is one of the important summer leafy vegetables in bangladesh. it is a popular and high mailto:luckyshamol6869@gmail.com 76 begum et al. nutritious leafy vegetable during kharif season. 100 g basella leaves contain 0.12 mg calcium, 1.2 mg iron, 0.08 mg thiamine and 1686 iu carotene (anon, 2000). it demands and popularity is rising due to its nutrient content. higher productivity from intercropping depends on judicious choice of component crops, suitable planting system or proportion of component crops (islam et al., 2006). maize is a c4 crop; its roots enter more than one meter in to the soil and can absorb nutrients from deeper layer. hybrid maize is an unbranched and erect cereal crop grown with wide spacing. several short duration and short stature vegetable like indian spinach may be grown in association with hybrid maize. indian spinach is the most compatible with maize for their contrasting phenology such as different growth habits, growth duration and demand for growth resources. maize takes longer time and offers an opportunity for intercropping. some vegetable crops might be a good intercrop with maize (uddin et al., 2009) and the practice also offers considerable yield advantage and higher economic return over sole cropping (singh et al., 2010; singh et al., 2002; kheroarand patra, 2013). however, literature is meagre regarding hybrid maize indian spinach intercropping under different planting systems. hence, this experiment was undertaken to find out suitable planting systems of hybrid maize and indian spinach intercropping system for higher productivity, economic return and food security. materials and methods a field experiment was undertaken at the agronomy research field, bari, joydebpur, gazipur (23°53′-24°21′n latitudes and 90°09′-92°39′e longitudes), regional agricultural research station (rars), jashore (22°48′-23°22′n latitudes and 88°51′-89°34′ e longitudes) and rars, ishurdi, pabna (24°03’-24°15’ n latitudes and 89°00’-89°11' e longitudes) during kharif season of 2016 and 2017. treatments included in the experiment were: t1 = hybrid maize normal row (75 cm  20 cm ) + 1 row indian spinach (plant to plant 25 cm), t2 = hybrid maize paired row (37.5 cm/150 cm/37.5cm  25 cm) + 1 row indian spinach (plant to plant 25 cm), t3 = hybrid maize paired row (37.5 cm/150 cm  20 cm) + 2 rows indian spinach (plant to plant 25 cm), t4 = hybrid maize paired row (37.5 cm/150 cm  20 cm) + 3 rows indian spinach (plant to plant 25 cm), t5 = sole maize (75 cm  25 cm) and t6 = sole indian spinach (40 cm  25 cm). the experiment was laid out in randomized complete block design with three replications and the unit plot size was 6m  5m. hybrid maize var. bari hybrid maize-9 in all locations and indian spinach var. bari indian spinach-2 at joydebpur and ishurdi but local indian spinach was used at jashorein both years. hybrid maize seeds were sown on 15 march, 2016 and 12 march, 2017 and indian spinach seedlings (25 days old) were transplanted on 13 march, 2016 and 10 march, 2017 at joydebpur, at jashore hybrid maize seeds were sown on 10 april, 2016 and 11 april, 2017 and indian spinach seedlings (20-25 days old) were transplanted on 8 april, 2016 and 9 april, 2017. but at ishurdi, maize seeds were sown and indian spinach seedlings were transplanted on the same day (4 april, 2016 and 23 march, 2017). the seeds of bari hybrid maize-9 were treated with provex at the rate of 3 g per one kg of seed in all locations. fertilizers were applied at the rate of 25076-121-72-5-1 kg ha-1 of n, p, k, s, zn, b (frg, 2012) as urea, triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate and boric acid for sole maize and intercrop. one third of n, whole amount of tsp, mop, gypsum, zinc sulphate and boric acid were applied as basal. remaining 2/3 n was top dressed at 20 and 40 days after sowing (das) of maize. in intercrop, extra n (40 kg/ ha) was applied in 2 splits at 20 and 40 dat as ring method to indian spinach. sole indian spinach was fertilized at the rate of 70-15-45-15 kg/ ha of n, p, k, s. one third of n and all other fertilizers were applied as basal. rest n was applied in 2 splits at 20 and 40 dat as ring method in all locations. light availability was measured by par ceptometer (model – lp-80, accu par, decagon, usa) in only joydebpur location. photo synthetically active radiation (par) was measured at 15-day intervals from 30 to 105 dat at around 11:30 am to 13:00 pm. the par was measured by par ceptometer (model – lp-80, accu par, decagon, usa). lp-80 has an 80 cm long sensor, which is usually used for below canopy measurement. another optional quantum sensor can be used for above canopy measurement through a cable connection. so, simultaneous measurement of par at above and below canopy is possible with this instrument. the respective sensors were simultaneously installed above and below of https://www.researchgate.net/profile/shyamal-kheroar https://www.researchgate.net/profile/shyamal-kheroar productivity of hybrid maize-indian spinach intercropping 77 the canopy (10 cm above the soil surface) for incident par (parinc) and transmitted par (part), respectively. four readings each of parinc and part were recorded at different spots of each plot. part indicated the light availability above underneath crop (indian spinach). the proportion of transmitted par (part) was expressed in percentage (ahmed et al., 2010): light availability, part (%) = part  100 parinc where, parinc = incident par, part = transmitted par data on yield contributing characters of maize were taken from randomly selected 5 plants from each plot. yields of both the crops were taken from whole plot area in all the locations. maize was harvested on 7 july, 2016 and 28 june 2017 and indian spinach was harvested 6 times in both the years (2 may, 12 may, 20 may, 30 may, 8 june and 18 june in 2016 and 29 april, 9 may, 17 may, 27 may, 5 june and 15 june in 2017) at joydebpur. on the other hand, maize was harvested on 20 and 25 july in 2016 and 2017, respectively, at jashore and at ishurdi, 13 and 15 july in 2016 and 2017, respectively. indian spinach was harvested only 3 times at jashore (29 may, 14 and 30 june in 2016 and 29 may, 15 june, 30 june in 2017) and 3 times at ishurdi (24 may, 10 and 26 june in 2016 and 4 june, 20 june, 10 july in 2017). in all locations, maize equivalent yield was computed by converting yield of intercrops on the basis of prevailing market price of individual crop following the formula of bandyopadhyay (1984) as given below: maize equivalent yield = yim + (yiisppisp)/ pm where, yim = yield of intercropped maize, yiisp = yield of intercropped indian spinach, pm = market price of maize and pisp = market price of indian spinach. collected data of both the crops were analyzed statistically and the means were adjudged using lsd(0.05) test. economic analysis was also done considering local market price of harvested crops. result and discussion light availability irrespective of treatments, availability of light (transmitted par) on indian spinach canopy was almost 100% at earlier growth stage 30 dat of indian spinach and it decreased with the increase of shade produced by maize canopy over the time up to 105 dat and then increased up to harvest due to leaf senescence of maize. the lowest light availability on indian spinach was observed at 105 dat in hybrid maize normal row (mnr) + 1 row indian spinach (isp) treatment and the highest was observed in sole isp treatment and light availability on indian spinach was more or less similar in mpr + 1 row isp, mpr + 2 rows isp and mpr + 3 rows isp. among the treatments, light availability on indian spinach canopy was more in the paired row than normal row of maize throughout the growing period (figure 1). 78 begum et al. fig. 1. light availability on isp canopy in hybrid maize + indian spinach intercropping system. effect on yield and yield components of maize number of grainscob-1, 1000grain weight and grain yield of maize were not significantly differed in both years at all locations. numerically the highest grain yield (8.03 and 8.01 t ha-1at joydebpur, 5.80 and6.07 t ha-1 at jashore and 6.86 and 6.63 t ha-1 at ishurdi during 2016 and 2017, respectively) were recorded in sole maize due to no intercrop competition for growth resources like light, nutrients, moisture and space in sole cropping (table 1). this corroborates with the findings of begum et al. (2016; 2020). the lowest grain yield were recorded in mpr + 3 rows isp at all locations. grain yield level at jashore and ishurdi was lower than joydebpur. it might be due to delayed sown of crops where comparatively higher temperature prevailed in cropping period in other two locations than joydebpur. crop faced higher temperature and heavy rainfall at taselling and silking stage which was harmful to pollination resulting yield was decreased. lizaso et al. (2018) reported that maize grain yield was reduced under heat stress mainly via pollen viability resulting in decreased the grain number and yield. the decrease in grain yield under intercrop situation varied from 1.0-12.6 % at joydebpur, 5.2-17.1 % at jashore and 13.4-22.2 % at ishurdi due to inter specific competition for growth resources among maize and indian spinach. table 1. grain yield of hybrid maize as influenced by different planting systems in maize + indian spinach intercropping during kharif 2016 and 2017 treatments grain yield (t ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 7.95 7.77 5.50 5.60 5.91 5.74 t2 = mpr + 1 row isp 7.47 7.35 5.40 5.23 5.53 5.44 t3 = mpr + 2 rows isp 7.35 7.26 5.37 5.07 5.41 5.24 t4 = mpr + 3 rows isp 7.02 7.22 5.30 5.03 5.38 5.16 t5 = sole maize 8.03 8.01 5.80 6.07 6.86 6.63 lsd(0.05) ns ns ns ns ns ns cv (%) 15.3 13.7 15.7 19.1 12.2 14.1 ns= not significant effect on yield of indian spinach number of plants m-2 and leafy vegetable yield of indian spinach were significantly influenced by different planting systems. the highest plants m-2 was observed in mpr + 3 rows isp in all locations (7.5 and 7.1 at joydebpur, 6.0 and 6.2 at jashore and 6.6 and 6.5 at ishurdi during 2016 and 2017, respectively) and the lowest in t2 treatment in all locations due to planting system. the highest 0 20 40 60 80 100 120 30 45 60 75 90 105 l ig h t a v a il a b il it y o n i s p ( % ) days after transplant t1=mnr +1 row isp t2=mpr +1 row isp t3=mpr +2 row isp t4=mpr +3 row isp t6=sole indian spinach (isp) 2016 0 20 40 60 80 100 120 30 45 60 75 90 105 l ig h t a v a il a b il it y o n i s p ( % ) days after transplant t1=mnr +1 row isp t2=mpr +1 row isp t3=mpr +2 row isp t4=mpr +3 row isp t6=sole indian spinach (isp) 2017 productivity of hybrid maize-indian spinach intercropping 79 biomass vegetable yield was found in sole indian spinach due to higher plant population per unit area and there was no intercrop competition for growth resources (table 2). among the intercrop treatments, the highest vegetable yield (18.30 and 17.37 t ha-1 at joydebpur, 12.00 and 9.83 t ha-1 at jashore and 8.78 and 8.91 t ha-1 at ishurdi during 2016 and 2017, respectively) were observed in mpr + 3 rows isp treatment. the lowest vegetable yield were observed in mpr + 1 row isp treatment due to variation of planting systems or number of plant population per unit area in both years at all locations. table 2. leafy vegetable yield of indian spinach as influenced by different planting systems in maize and indian spinach intercropping during kharif 2016 and 2017 treatments leafy vegetable yield (t ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 12.02 11.70 9.9 8.50 7.93 7.86 t2 = mpr + 1 row isp 8.56 6.27 5.95 4.20 3.68 4.13 t3 = mpr + 2 rows isp 12.00 10.07 9.85 7.53 7.21 7.80 t4 = mpr + 3 rows isp 18.30 17.37 12.0 9.83 8.78 8.91 t5 = sole maize t6 = sole indian spinach 40.35 35.25 20.4 15.47 16.61 16.36 lsd(0.05) 6.00 6.00 4.90 2.82 3.57 2.45 cv (%) 11.75 13.58 15.39 11.43 14.75 9.99 vegetable yield of indian spinach at jashore and ishurdi was lower than joydebpur. it might be due to lower number of plant population per unit area and the number of plucking or cutting of indian spinach at jashore and ishurdi were less (3 times) than that of joydebpur (6 times). evaluation of intercrop productivity hybrid maize indian spinach intercrop productivity was evaluated on the basis of land equivalent ratio and maize equivalent yield (bandyophadhyay, 1984). land equivalent ratio (ler) and maize equivalent yield (mey) of maize + indian spinach intercropping in all locations are presented in table 3 and table 4. the ler values in the intercrops ranged from (1.14 to 1.32 and 1.10 to 1.39 at joydebpur, 1.22 to 1.50 and 1.13 to 1.47 at jashore and 1.03 to 1.34 and 1.07 to 1.35 at ishurdi in 2016 and 1017, respectively) which indicated (14 to 32 % and 10 to 39% at joydebpur, 22 to 50% and 13 to 47% at jashore and 3 to 34% and 7 to 35% at ishurdi in 2016 and 1017, respectively) land utilization increased by intercrop cultivation than growing maize and indian spinach as sole crop. table 3. land equivalent ratio as influenced by different planting systems in maize + indian spinach intercropping during kharif 2016 and 2017 treatments land equivalent ratio joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 1.29 1.30 1.44 1.47 1.34 1.35 t2 = mpr + 1 row isp 1.14 1.10 1.22 1.13 1.03 1.07 t3 = mpr + 2 rows isp 1.22 1.20 1.41 1.33 1.22 1.27 t4 = mpr + 3 rows isp 1.32 1.39 1.50 1.47 1.31 1.33 t5 = sole maize 1.00 1.00 1.00 1.00 1.00 1.00 the highest ler (1.32 and 1.39 at joydebpur and 1.50 and 1.47 at jashore in 2016 and 2017, respectively) was observed in mpr + 3 rows isp treatment. on the other hand, at ishurdi, the highest ler (1.34 and 1.35 in 2016 and 2017, respectively) was observed in mnr + 1 row isp treatment followed by mpr + 3 rows isp treatment. mey of all the intercropping systems was higher than sole maize in all locations indicating higher productivity of intercropping than sole maize. among the 80 begum et al. intercropping, the highest maize equivalent yield (19.22 and 18.80 t ha-1 at joydebpur, 13.30 and 11.58 t ha-1 at jashore and 11.23 and 11.10 t ha-1 at ishurdi in 2016 and 2017, respectively) was observed in t4 treatment (mpr + 3 rows isp) followed by t1 (mnr + 1 row isp). the lowest was observed in t5 (sole maize) in all locations. dhima et al. (2007) reported that intercropping maximizing land use and increasing crop yield. table 4. maize equivalent yield as influenced by different planting systems in maize + indian spinach intercropping during kharif 2016 and 2017 treatments maize equivalent yield (t ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 15.96 15.57 12.10 11.27 11.20 10.98 t2 = mpr + 1 row isp 13.18 11.53 9.47 8.03 7.98 8.19 t3 = mpr + 2 rows isp 15.35 13.97 11.94 10.09 10.22 10.44 t4 = mpr + 3 rows isp 19.22 18.80 13.30 11.58 11.23 11.10 t5 = sole maize 8.03 8.01 5.80 6.07 6.86 6.63 market price (tk kg-1): maize = 15, indian spinach = 10 in all locations in both years economic performance economic analysis is an important tool to evaluate the economic feasibility of intercropping systems and monetary advantage was evaluated according to shah et al. (1991). benefit cost analysis of maize + indian spinach intercropping systems in 2016 and 2017 at all locations are presented in table 5a to 5d. among intercropping treatments, the highest gross return (tk. 288300 and tk. 282000 ha-1 at joydebpur, tk. 199500 and tk. 173700 ha-1 at jashore and tk. 168450 and tk. 166500 ha-1 in 2016 and 2017, respectively) was observed in t4 treatment (hybrid maize paired row + 3 rows indian spinach planting system) and it was close to t1 owing to higher mey in all locations. the gross margin followed the similar trend of gross return. the maximum cost of production was recorded in t1 followed by t4 treatments. among intercropping treatments, the highest benefit cost ratio (3.13 and 3.07 at joydebpur, 2.26 and 1.97 at jashore and 2.11 and 2.08 at ishurdi in 2016 and 2017, respectively) was obtained from t4 (hybrid maize paired row + 3 rows indian spinach planting system) followed by t1 (hybrid maize normal row + 1 row indian spinach planting system). this result has been supported by the findings of islam et al. (2013) and begum et al. (2020). table 5a. gross return of maize + indian spinach intercropping under different planting system treatments gross return (tk. ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 239400 233550 181500 169050 168000 164700 t2 = mpr + 1 row isp 197700 172950 142050 120450 119700 122850 t3 = mpr + 2 rows isp 230250 209550 179100 151350 153300 156600 t4 = mpr + 3 rows isp 288300 282000 199500 173700 168450 166500 t5 = sole maize 120450 120150 87000 91050 102900 99450 table 5b. cost of cultivation of maize + indian spinach intercropping under different planting system treatments cost of cultivation (tk. ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 90000 90000 88370 88370 80000 80000 t2 = mpr + 1 row isp 84000 84000 86370 86370 79000 79000 t3 = mpr + 2 rows isp 87000 87000 87370 87370 79500 79500 t4 = mpr + 3 rows isp 92000 92000 88370 88370 80000 80000 https://onlinelibrary.wiley.com/doi/full/10.1002/fes3.260#fes3260-bib-0012 productivity of hybrid maize-indian spinach intercropping 81 t5 = sole maize 80000 80000 65370 65370 75000 75000 table 5c. gross margin of maize and indian spinach intercropping under different planting system treatments gross margin (tk. ha-1) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 149400 143550 93130 80680 88000 84700 t2 = mpr + 1 row isp 113700 88950 55680 34080 40700 43850 t3 = mpr + 2 rows isp 143250 122550 91730 63980 73800 77100 t4 = mpr + 3 rows isp 196300 192000 111130 85330 88450 86500 t5 = sole maize 40450 40150 21630 25680 27900 24450 table 5d. benefit cost ratio of maize and indian spinach intercropping under different planting system treatments benefit cost ratio (bcr) joydebpur jashore ishurdi 2016 2017 2016 2017 2016 2017 t1 = mnr + 1 row isp 2.66 2.60 2.05 1.91 2.10 2.06 t2 = mpr + 1 row isp 2.35 2.06 1.64 1.39 1.60 1.56 t3 = mpr + 2 rows isp 2.65 2.41 2.05 1.73 1.93 1.97 t4 = mpr + 3 rows isp 3.13 3.07 2.26 1.97 2.11 2.08 t5 = sole maize 1.51 1.50 1.33 1.39 1.32 1.33 market price (tk kg-1): maize = 15, indian spinach = 10 in all locations in both years conclusion two years result revealed that all the intercropping systems showed better productivity than sole maize. hybrid maize paired row (37.5 cm/150 cm/37.5 cm  20 cm) + 3 rows indian spinach intercropping and hybrid maize normal row (75 cm  20 cm) + 1 row indian spinach intercropping might be agronomically feasible and economically profitable in all locations (joydebpur, jashore and ishurdi). references anonymous. 2000. puishaker utpadon projukti. in: shabjir unnatojat o utpadon paddhoti (bengali). s.m.m. hossain. ed. horticulture research center, bari, gazipur. 46p. ahmed, f., m.n. islam, m.t. rahman, m.a. jahan and m.s.a. khan. 2010. leaf area index, radiation interception, dry matter production and grain yield of hybrid maize as influenced by plant spacing. bangladesh agron. j. 13(1 & 2): 51-58. bandyopadhyay, s.n. 1984. nitrogen and water relations in grain sorghum-legume intercropping systems. phd. dissertation, indian agril. res. inst., new delhi. begum, a.a, m.a.k. mian, s.m.a.h.m. kamal, m.r. karim, r.r. saha and m.a. hossain. 2020. planting system effects on intercropping of gardenpea and sorghum. bangladesh agron. j. 23(2): 59-68. begum, a.a., m.s.u. bhuiya, s.m.a. hossain, amlna khatun and s.k. das. 2016. effect of planting system of potato and plant density of maize on productivity of potatohybrid maize intercropping system. bangladesh j. agril. res. 41(3): 397-409. dhima, k.v., a.s. lithourgidis, i.b. vasilakoglou and c.a. dordas. 2007. competition indices of common vetch and cereal intercrops in two seeding ratio. field crops res. 100(2-3): 249-256. frg. 2012. fertilizer recommendation guide, bangladesh agricultural research council (barc). farmgate, dhaka 1215. 274p. hossain, m. 2021. why farmers in northern bangladesh are turning to corn for food security. online article published on 5 may 2021 in the daily prothom https://www.researchgate.net/scientific-contributions/kico-dhima-35791443 https://www.researchgate.net/profile/a-lithourgidis https://www.researchgate.net/profile/ioannis-vasilakoglou https://www.researchgate.net/profile/christos-dordas https://www.researchgate.net/journal/field-crops-research-0378-4290 82 begum et al. alo.https://www.weforum.org/agenda/2021/05/why-farmers-in-northern-bangladesh-are-turningto-corn-for-food-security. islam, m.n., m.m. haque and a. hamid. 2006. planting arrangement and population density effects on the physiological attributes and productivity of maize-bushbean intercropping systems. bangladesh j. agril. res. 31(3): 353-364. islam, m.n., m. akhteruzzaman and m.s. alom. 2013. split application of inorganic fertilizers in potato (solanumtuberosum l.)-hybrid maize (zea mays l.) intercropping system. bangladesh j. agril. res. 38(3): 447-453. islam, t.m.t. and a.k. kaul. 1986. prospects of maize in bangladesh. fao/undp publication, dhaka, bangladesh. kheroar, s. and b. patra. 2013. advantages of maize-legume intercropping systems. j. agril. sci. tech. 3(3): 733-744. kumar, r., v. rajasree, l. sagar, u. tripura, k. karthick, r. karthick and g. prasath. 2018. underutilized vegetables as rich source of medicinal value: a boon for the pharmaceutical industries and farmer income. int. j. chem. stud. 6(4): 3320-3323. kumar, s.s., p. manoj and p. giridhar. 2015. nutrition facts and functional attributes of foliage of basella spp. lwt – food sci. technol. 64(1): 468-474. lizaso, j.i., m.r. ramos, l. rodriguez and c.g. leal. 2018. impact of high temperatures in maize: phenology and yield components. field crops res. 216: 129-140. mahfuza, s.n., m.n. islam, a. hannan, m. akhteruzzaman and s. begum. 2012. intercropping different vegetables and spices with pointed gourd. j. expt. biosci. 3(1): 77-82. shah, n.h., p.k. koul, b.a. khanday and d. kachrov. 1991. production potential and monetary advantage index of maize intercropped with different grain legumes. indian j. agron. 36(1): 23-28. singh, g., r.k. mehta and r.v. singh. 2002. energetics, yield, water use and economics of rice-based cropping systems in floodprone situation of eastern uttar pradesh. indian j. agric. sci. 72(2): 6366. singh, n.k., b. rai and r. kumar. 2010. production potential of winter maize (zea mays l.) based intercropping system. environ. ecol. 28(4a): 2449-2452. uddin, m.j., m.a. quayyum and k.m.s. alahuddin. 2009. intercropping of hybrid maize with short duration vegetables at hill valleys of bandarban. bangladesh j. agril. res. 34(1): 51-57. https://www.researchgate.net/profile/shyamal-kheroar https://www.researchgate.net/profile/bikas-patra https://www.researchgate.net/journal/journal-of-agricultural-science-and-technology-b-2161-6264 https://www.researchgate.net/journal/journal-of-agricultural-science-and-technology-b-2161-6264 hossain, m. 2021. why farmers in northern bangladesh are turning to corn for food security. online article published on 5 may 2021 in the daily prothom alo.https://www.weforum.org/agenda/2021/05/why-farmers-in-northern-bangladesh-are-turning-to-corn-f... microsoft word 11. baj-478e bangladesh agron. j. 2024, 26(2): 86-99 growth and yield performance of mustard and rapeseed varieties as influenced by different sowing techniques k.m.t. aziz1, s. razia2, m.h. ali3, m. hasanuzzaman3, t.a. sourav4 and s.m. masum3* 1public relation department, chattogram metropolitan office, chattagram, bangladesh 2ais, chattogram region, department of agricultural extension, chattagram, bangladesh 3department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 4independent researcher, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: smmasum607@yahoo.com (received: 30 april 2024, accepted: 2 july 2024) keywords: brassica, system of mustard intensification, growth, yield, oil percentage abstract an experiment was conducted at the agronomy field, sher-e-bangla agricultural university, dhaka, from november 2013 to february 2014 to investigate mustard and rapeseed varieties' growth and yield performances influenced by different sowing techniques. the experiment was laid out in a factorial randomized complete block design (rcbd) with three replications. the four varieties were bari sarisha-11, bari sarisha-13, bari sarisha-15, sau sarisha 2 (v1, v2, v3, and v4 respectively) and sowing techniques included broadcasting, line sowing, raised bed, system of mustard intensification (smi) (s1, s2, s3, and s4 respectively). results showed that the highest plant height (143.58 cm) was achieved at the combination of bari sarisha-11 and the raised bed technique (v1s3) at harvest. though the highest leaf number varied in different varieties, it was produced by the smi technique. bari sarisha-15 and the smi techniques produced the highest number of primary branches, though bari sarisha-11 produced the maximum secondary branches with the same technique. bari sarisha-11 performed best at all the das regarding dry matter accumulation (g) and the values resulting in 1.07, 11.44, 21.3, and 25.87g. smi also proved to be the best, except for 30 das. the highest seed yield (3.74 t ha−1 and 3.80 t ha−1) was obtained using bari sarisha-11 and smi techniques, respectively. the highest biological yields (12.80 t ha−1 and 12.86 t ha−1) were obtained by bari sarisha-11 and smi technique, respectively. however, the maximum harvest index (34.84% and 32.45%) and highest oil percentages (40.65% and 41.38%) were obtained by bari sarisha-15 and line sowing, respectively. as such the var. bari sarisha-11 could be expected good yield following the smi technique. introduction bangladesh's primary edible oil source is the brassica oil crop. it makes up 59.4% of the nation’s total production of oil seeds (ais, 2010). according to bbs (2010), these crops only comprise about 3% of bangladesh's farmed land. the rapeseed and mustard crops occupy 2.42 lac hectares of total land and 2.22 lakh metric tons of yearly production. seed yield and other yield-contributing characteristics considerably varied among the varieties of rapeseed and mustard (bari, 2001). uddin et al. (1987) reported a significant yield difference between the varieties of rapeseed and mustard of the same species. singh et al. (1999) was found oil content variation due to different varieties and methods. they estimated the oil content of different varieties from different species and the highest oil content (44.3%) from variety pys841 (b. campestris) and the lowest (40.8%) from kranti (b. juncea) by the soxhlet method. according to hossain et al. (2013), the sowing techniques significantly impacted the seed yield. in his investigation, line sowing produced the most seed yield, and broadcasting produced the lowest seed yield. several studies suggest that a higher number of siliqua plant−1 has the greatest effect on the seed yield of rape and mustard (thurling, 1974; mendham et al., 1981; rahman et al., 1988). rahman et al. 2019 stated that the highest biological yield per hectare (5.08 tonnes) was obtained from the broadcast method with the bari sarisha-15 and hossain et al. (2015) further supported the effectiveness of the broadcast method, particularly when combined with two irrigations. bharat et al. (2022) found that early sowing 87 aziz et al. led to higher utilization and accumulation of various agromet indices and the planting geometry of 30 cm × 10 cm was found to increase yields. the mustard intensification (smi) system allows farmers with limited resources to enhance crop yields by minimizing the use of water and seeds while also advocating for ecological and market-oriented principles (lyu et al., 2021). considering the valuable aspects, the study evaluates the impacts of varieties, sowing techniques and identifying the best outcome. materials and methods the research was conducted at the agronomy department of sher-e-bangla agricultural university, dhaka, from november 2014 to february 2015. the field was located in the southeast part of the academic building, and the soil was from the agroecological zone of the madhupur tract (aez 28). soil samples were collected from 0-15 cm depths, mainly sandy to silty and loamy in texture. soil resources and development institute (srdi) conducted soil analyses. the experimental area is in a subtropical climate, with heavy rainfall during the kharif season and less during rabi. the seeds were collected from bangladesh agricultural research institute (bari), gazipur, bangladesh, with a germination percentage of 90%. the land was prepared by plowing and harrowing removing stubbles and weeds and divided into unit plots, spaded one day before planting and fertilized uniformly with sulfur (gypsum) and boron (boric powder) fertilizers. 1/3rd of the urea and full doses of other fertilizers were applied at the time of final land preparation. the remaining urea was top-dressed at 17 and 27 das. the rate applied in the field for n, p2o5, k2o, and zn was 115, 82, 51, and 7.8 kg ha−1 respectively. the experiment was comprised with four mustard and rapeseed varieties and four sowing techniques viz. a. varieties: v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2; b. sowing techniques: s1= broadcasting, s2= line sowing, = raised bed, s4= system of mustard intensification (smi). the experiment was laid out in factorial randomized complete block design (rcbd) with three replications and unit plot size 3 m × 3 m. the germination test was conducted using petri dishes, each containing 25 seeds and data on emergence was collected on a percentage basis by using the following formula: germination (%)= number of seeds germinated number of seeds taken for germination × 100 crop growth rate (cgr), relative growth rate (rgr) and harvest index were calculated by using the following standard formulas as shown below: crop growth rate = w2-w1 t2-t1 g plant−1 day−1 (w1= total plant dry matter at time t1, w2 = total plant dry matter at time t2) relative growth rate = lnw2-lnw1 t2-t1 g plant−1 day−1 (w1 = total plant dry matter at time t1, w2 = total plant dry matter at time t2, ln = natural logarithm) harvest index (%)= grain yield biological yield ×100 the data was analyzed using cropstat, a computer program from irri, philippines, to determine the significance level and compare mean differences with a 5% level of significance. results and discussion effect of varieties and sowing techniques on plant height different varieties significantly influenced mustard and rapeseed plant height (cm) throughout the growing period (fig. 1). growth and yield performance of mustard and rapeseed by sowing techniques 88 fig. 1. effect of varieties and sowing techniques on plant height of mustard and rapeseed plants at different das. according to findings, bari sarisha-11 (v1) showed the highest plant height, which were 96.28, 123.38, 133.03, and 132.88 cm at 45, 60, 75 das, and at harvest, respectively. though sau sarisha 2 (v4) was slightly taller than bari sarisha-11 at 30 das, the difference is insignificant. the var. bari sarisha-13 was the smallest. it also varied significantly due to different sowing techniques (fig. 1). at 30, 45, and 60 das, the raised bed performed well, producing the tallest plants, which were 34.86, 99.64, and 113.49 cm respectively. however, smi performed well at 75 das and at harvest, producing 120.88 and 121.31 cm. combined effect of varieties and sowing techniques on plant height plant height was not significantly affected by the combination of variety and sowing techniques at 30, 60, and 75 das and at harvest but significantly affected at 45 das, as shown in table 1. table 1. combined effect of varieties and sowing techniques on plant height (cm) treatments 30 das 45 das 60 das 75 das at harvest v1s1 42.11 a 107.33 ab 126.08 ab 123.34 b 123.02 b v1s2 31.56 b-e 101.00 b-d 120.17 a-c 123.00 b 122.82 b v1s3 37.45 a-c 113.00 a 136.26 a 144.11 a 143.58 a v1s4 16.89 g 63.78 g 111.02 b-e 141.67 a 142.10 a v2s1 34.11 a-d 82.22 e 98.83 de 96.56 de 96.25 cd v2s2 23.22 e-g 65.11f g 80.58 f 87.56 e 87.31 d v2s3 27.55 d-f 86.11 e 98.42 de 99.45 de 99.21 cd v2s4 18.00 g 46.33 h 95.08 ef 118.33 bc 118.97 b v3s1 36.33 a-d 96.89 d 102.81 c-e 102.33 c-e 102.10 cd v3s2 29.66 c-f 87.55 e 99.81 de 99.22 de 98.80 cd v3s3 35.22 a-d 94.89 d 100.7 de 100.22 de 99.98 cd v3s4 21.11 f 82.22 e 110.68 b-e 112.40 b-d 112.69 bc v4s1 40.78 a 96.44 d 110.49 b-e 111.00 b-d 110.50 bc v4s2 37.55 a-c 100-00 cd 112.87 b-d 110.67 b-d 110.55 bc v4s3 39.22 ab 104.55 bc 118.57 bc 119.66 b 119.35 b v4s4 17.00 g 71.67 f 96.18 d-f 111.11 b-d 111.47 bc cv (%) 17.4 4.9 9.8 8.9 8.9 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi at 30 das, the highest plant height (42.11 cm) was recorded from the combination of bari sarisha-11 and broadcasting technique (v1s1), which was statistically similar with v1s3, v2s1, v3s1, v3s3, v4s1, v4s2, and v4s3. a combination of bari sarisha-11 and raised bed technique (v1s3) scored the highest plant height (113 cm) at 45 das, statistically similar to v1s1. however, the combination of bari sarisha-11 and the raised bed technique (v1s3) performed best at all the other dass. effect of varieties and sowing techniques on leaf number leaf number was significantly affected at 45, 60, and 75 das and at harvest but not at 30 das (fig. 2). at 30, 45, and 75 das, the maximum leaf numbers (7.36, 61.75, and 94.11) were recorded at sau sarisha-2. at 60 das, the maximum leaf number (96.36) was observed at bari sarisha-15. 0 20 40 60 80 100 120 140 160 30 das 45 das 60 das 75 das at harvest pl an t h ei gh t ( cm ) days after sowing (das) bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 0 20 40 60 80 100 120 140 160 30 das 45 das 60 das 75 das at harvest pl an t h ei gh t ( cm ) days after sowing (das) broadcasting line sowing raised bed smi 89 aziz et al. however, it was not significantly affected by sowing techniques at 30 das (fig. 2). smi showed the best results (59.25, 142.17, 201.81, and 78.58) at every das except 30 das. fig. 2. effect of varieties and sowing techniques on leaf number of mustard and rapeseed plants at different das. combined effect of varieties and sowing techniques on leaf number leaf number was not significantly affected by the combination of variety and sowing technique at 30 das but significantly affected at 45, 60, and 75 das and at harvest (table 2). table 2. combined effect of variety and sowing technique on leaf number at 30, 45, 60, and 75 das, and at harvest treatments 30 das 45 das 60 das 75 das at harvest v1s1 6.78 ab 31.67 f 73.44 f 59.22 d 21.67 gh v1s2 8.00 a 25.56 g 61.89 g 33.33 f-h 18.00 hi v1s3 7.11 ab 28.33 fg 62.78 g 43.89 e 23.33 fg v1s4 6.56 ab 52.67 cd 132.33 c 208.00 b 112.67 a v2s1 6.00 b 10.78 i 26.44 k 8.11 j 3.00 k v2s2 6.33 ab 18.67 h 48.00 i 23.44 i 8.00 j v2s3 6.67 ab 24.56 g 54.00 hi 30.22 g-i 13.67 i v2s4 6.89 ab 44.11 e 117.22 d 168.00 c 41.00 d v3s1 6.22 ab 30.56 f 63.11 g 25.44 hi 13.33 i v3s2 6.33 ab 43.22 e 71.33 f 28.11 g-i 17.67 hi v3s3 6.33 ab 56.33 c 83.33 e 59.11 d 35.00 e v3s4 7.00 ab 72.56 a 167.67 a 162.33 c 66.33 c v4s1 7.56 ab 51.22 d 41.00 j 32.11 f-i 18.00 hi v4s2 7.56 ab 73.33 a 57.33 gh 35.11 e-g 19.67 gh v4s3 7.67 ab 54.78 cd 48.56 i 40.33 ef 27.33 f v4s4 6.67 ab 67.67 b 151.44 b 268.89 a 94.33 b cv (%) 15.7 5.4 5.2 7.2 8.9 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi at 30 das, maximum leaf number (8) was recorded at the combination of bari sarisha-11 and line sowing technique (v1s2), which was statistically similar to other combinations except v2s1. at 45, 60, and 75 das and at harvest, v4s2, v3s4, v4s4, and v1s4 performed best respectively. effect of varieties and sowing techniques on the number of primary branches throughout the life cycle, variation had a major impact on the number of primary branches (fig. 3). 0 20 40 60 80 100 120 30 das 45 das 60 das 75 das at harvest le af n um be r days after sowing (das) bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 0 20 40 60 80 100 120 140 160 180 200 220 30 das 45 das 60 das 75 das at harvest le af n um be r days after sowing (das) broadcasting line sowing raised bed smi growth and yield performance of mustard and rapeseed by sowing techniques 90 fig. 3. effect of varieties and sowing techniques on the number of primary branches of mustard and rapeseed plants at different das. at 30 das, the maximum number of primary branches (3) were recorded at sau sarisha-2, which was statistically similar to bari sarisha-11 (3) and bari sarisha-15 (3). however, bari sarisha-15 proved the best in terms of no. of primary branches at all the other das and at harvest respectively. at 30 das, the sowing strategy had no discernible effect on the number of primary branches; however, at 45, 60, and 75 das and during harvest, it did (fig. 3). at 30 das, the maximum number of primary branches (3) were recorded using the raised bed technique, which was statistically similar to line sowing and the smi technique. on the other hand, the smi technique proved the best in terms of no. of primary branches at all the other das and at harvest, resulting in 8, 11, 11, and 11 respectively. additionally, hossain et al. (2013) found that the seeding technique significantly affected the number of total branches produced per plant. combined effect of varieties and sowing techniques on the number of primary branches the number of primary branches in a plant was not significantly affected by the combination of variety and sowing technique at 30 and 45 das and at harvest (table 3). table 3. combined effect of varieties and sowing techniques on the number of primary branches treatments 30 das 45 das 60 das 75 das at harvest v1s1 2.33 b-e 4.33 hi 4.89 hi 5.11 hi 5.00 hi v1s2 2.67 a-d 4.67 g-i 5.78 f-h 5.67 g-i 5.78 f-i v1s3 3.33 ab 5.00 f-i 6.11 f-h 6.33 f-h 6.33 f-h v1s4 3.33 ab 6.67 c-f 9.67 b-d 10.33 bc 10.33 ab v2s1 1.67 c-e 3.67 i 3.45 i 4.44 i 4.33 i v2s2 1.00 e 3.67 i 4.67 hi 4.56 i 4.67 hi v2s3 1.67 c-e 5.67 e-h 5.44 gh 5.67 g-i 5.67 g-i v2s4 1.33 de 5.67 e-h 11.67 a 12.67 a 11.33 a v3s1 2.33 b-e 7.67 a-d 6.89 fg 6.89 e-g 7.22 d-g v3s2 3.33 ab 8.00 a-d 8.44 de 8.33 de 8.67 b-e v3s3 3.67 ab 8.00 a-d 9.22 cd 9.00 cd 9.00 b-d v3s4 2.67 a-d 9.33 a 11.00 ab 11.67 ab 11.67 a v4s1 2.67 a-d 6.33 d-g 7.11 ef 7.22 ef 7.11 e-g v4s2 3.33 ab 7.33 b-e 7.22 ef 8.11 de 7.56 c-f v4s3 4.00 a 8.33 a-c 8.78 d 9.00 cd 9.11 bc v4s4 3.00 a-c 8.67 ab 10.45 a-c 11.22 ab 11.22 a lsd(0.05) 1.36 1.75 1.52 1.45 1.83 cv (%) 30.8 16.3 12.1 11.0 14.0 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi however, it was significant at 60 and 75 das. at 30 das, the maximum number of primary branches was recorded at the combination of sau sarisha-2 and raised bed technique (v4s3), while the minimum number at the combination of bari sarisha-13 and line sowing (v2s2). at 45 das, the maximum number of primary branches was at the combination of bari sarisha-15 and smi technique (v3s4), while the minimum number was at the combination of bari sarisha-13 and broadcast sowing technique (v2s1). at 60 das, the maximum number of primary branches was at the combination of 91 aziz et al. bari sarisha-15 and smi technique (v2s4), while at 75 das, the minimum number was at the combination of bari sarisha-13 and broadcast sowing technique (v2s1). effect of varieties and sowing techniques on the number of secondary branches number of secondary branches was significantly affected by variety throughout the life cycle (fig. 4). at 45 das, the maximum number of secondary branches (8) was recorded at bari sarisha-11, and the minimum number of secondary branches (1) at bari sarisha-15. on 60 and 75 das and at harvest, the maximum number of secondary branches (23, 26, and 28) was recorded at bari sarisha-11 and the minimum number of secondary branches (13, 16, and 17) at bari sarisha-13. the sowing techniques significantly affected the number of secondary branches throughout the life cycle (fig. 4). at 45 das, the maximum number of primary branches (6) was recorded using the smi technique and the minimum number of secondary branches (1) by broadcasting technique which was statistically similar to line sowing. at 60 and 75 das and at harvest, the maximum number of secondary branches (41, 47, and 51) was recorded at the smi technique and the minimum number of secondary branches (8, 9, and 9) at the broadcast sowing technique. fig. 4. effect of varieties and sowing techniques on the number of secondary branches of mustard and rapeseed plants at different das. combined effect of varieties and sowing techniques on the number of secondary branches the combination of variety and sowing technique throughout the life cycle significantly affected the number of secondary branches, as shown in table 4. at 45 das, the maximum number of secondary branches (14) was recorded at the combination of bari sarisha-11 and smi technique (v1s4). the minimum number of secondary branches (0) was observed both at the combination of bari sarisha-15 and line sowing (v3s2) and bari sarisha-15 and raised bed technique (v3s3) which was statistically similar with v2s1, v3s1, v4s1, and v4s2. at 60 and 75 das and at harvest, the maximum number of secondary branches (52, 62, and 70) was recorded at the combination of bari sarisha-11 and smi technique (v1s4). the minimum number of secondary branches (2, 3, and 3) was observed at the combination of bari sarisha-13 and broadcast sowing technique (v2s1). table 4. combined effect of varieties and sowing techniques on the number of primary branches treatments 45 das 60 das 75 das at harvest v1s1 2.89 de 11.89 e-h 12.00 e-g 12.00 e-g v1s2 4.45 c 13.78 e-g 14.00 ef 14.11 d-g v1s3 9.00 b 14.56 ef 15.67 de 16.00 de v1s4 13.89 a 52.00 a 62.00 a 70.33 a v2s1 0.56 h 2.33 i 2.78 h 2.56 h v2s2 1.67 fg 8.78 h 10.67 fg 11.00 fg v2s3 2.67 d-f 9.55 gh 15.00 de 16.00 de v2s4 4.89 c 30.89 d 37.78 c 41.33 c v3s1 0.44 h 10.11 f-h 10.33 fg 10.33 fg v3s2 0 h 13.33 e-g 15.00 de 15.00 d-f growth and yield performance of mustard and rapeseed by sowing techniques 92 v3s3 0 h 12.56 e-h 18.00 d 18.00 d v3s4 4.22 c 36.00 c 39.33 c 40.67 c v4s1 1.00 gh 9.67 gh 10.00 g 10.00 g v4s2 0.56 h 12.33 e-h 12.67 e-g 12.67 e-g v4s3 3.67 d 15.45 e 18.67 d 18.67 d v4s4 2.55 ef 45.56 b 50.11 b 50.00 b lsd(0.05) 1.05 4.52 3.94 4.98 cv (%) 19.2 14.5 11 13.2 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi effect of varieties and sowing techniques on dry matter accumulation variation significantly affected dry matter (g) production throughout the life cycle (fig. 5). bari sarisha-11 performed well at all the das, resulting in 1.07, 11.44, 21.3, and 25.87 g. bari sarisha-13 holds the second position except at 30 das. dry matter (g) production was also significantly affected by the sowing techniques throughout the lifecycle (fig. 5). smi performed best at all the dass except at 30 das, resulting in 14.85, 28.68, and 36.44 g. according to sushma et al. (2023), transplanting seedlings that are 25 days old with a spacing of 30 cm × 30 cm under the system of mustard intensification led to increased dry matter production. fig. 5. effect of varieties on dry matter accumulation of mustard and rapeseed plants at different das. combined effect of varieties and sowing techniques on dry matter accumulation dry matter accumulation (g) was significantly affected by the combination of variety and sowing technique at 30, 45, and 60 das but not significantly at 75 das (table 5). at 30 das, maximum dry matter (1.7 g) accumulation was recorded at the combination of bari sarisha-11 and raised bed technique (v1s3) and minimum dry matter (0.45 g) accumulation was observed at the combination of bari sarisha-15 and smi technique (v3s4) which was statistically similar with v1s1, v1s4, v2s1, v2s2, v2s4, v3s1, v3s2, and v4s4. on 45 das, maximum dry matter (19.2 g) production was recorded using the combination of bari sarisha-11 and smi technique (v1s4). at 60 das, maximum dry matter (35.12 g) production was recorded using the combination of bari sarisha-11 and smi technique (v1s4). at 75 das, maximum dry matter (39.93 g) production was recorded using the combination of bari sarisha11 and smi technique (v1s4) which was statistically similar to v2s4 and v4s4. table 5. combined effect of variety and sowing technique on dry matter accumulation (g) at 30, 45, 60, and 75 das. treatments 30 das 45 das 60 das 75 das v1s1 0.61 e-g 5.25 hi 6.96 ki 11.53 gh v1s2 1.41 b 6.11 g 20.12 e 24.01 de v1s3 1.70 a 15.18 c 23.00 d 28.02 cd 0 5 10 15 20 25 30 35 40 30 das 45 das 60 das 75 das d ry m at te r w ei gh t ( g) days after sowing (das) bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 0 5 10 15 20 25 30 35 40 30 das 45 das 60 das 75 das d ry m at te r w ei gh t ( g) days after sowing (das) broadcasting line sowing raised bed smi 93 aziz et al. v1s4 0.57 fg 19.20 a 35.12 a 39.93 a v2s1 0.58 fg 3.43 j 6.42 l 7.68 h v2s2 0.61 e-g 5.83 gh 10.47 hi 13.94 fg v2s3 0.83 de 6.27 g 16.39 f 20.61 e v2s4 0.48 g 11.24 e 28.91 b 34.52 ab v3s1 0.48 g 5.05 i 6.81 l 8.56 gh v3s2 0.63 e-g 5.23 hi 8.47 jk 11.18 gh v3s3 1.24 bc 7.78 f 12.06 h 18.56 ef v3s4 0.45 g 12.99 d 25.96 c 33.34 bc v4s1 0.81 d-f 3.93 j 6.52 l 10.45 gh v4s2 0.83 de 4.98 i 9.02 ij 18.57 ef v4s3 1.05 cd 9.94 e 14.5 g 24.02 de v4s4 0.54 g 15.98 b 24.72 c 37.98 ab cv (%) 18.3 4.4 6.1 15.4 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi effect of varieties and sowing techniques on crop growth rate crop growth rate (cgr) is a measure of the increase in size, mass, or number of crops over a period of time (fig. 6). cgr was significantly affected by varieties throughout the life cycle. at 30-45 das, the highest cgr (0.691 g plant−1 day−1) was recorded at bari sarisha-11 and the lowest cgr (0.405 g plant−1 day−1) at bari sarisha-13. on 45-60 das, the highest cgr (0.658 g plant−1 day−1) was recorded at bari sarisha-11 but at 60-75 das, the highest cgr (0.604 g plant−1 day−1) was recorded at sau sarisha-2. crop growth rate was significantly affected by the sowing technique throughout the life cycle (fig. 6). at 30-45 das, the highest cgr (0.956 g plant−1 day−1) was recorded using the smi technique, and the lowest cgr (0.253 g plant−1 day−1) at broadcast sowing technique. on 45-60 das and 60-75 das, the highest cgr (0.658 g plant−1 day−1 and 0.518 g plant−1 day−1) was recorded at smi technique. fig. 6. effect of varieties and sowing techniques on cgr of mustard and rapeseed plants at different das. combined effect of varieties and sowing techniques on crop growth rate crop growth rate was significantly affected by the combination of variety and sowing technique at 30-45 and 45-60 das but not significantly at 60-75 das, as shown in table 6. at 30-45 das, highest cgr (1.242 g plant−1 day−1) was recorded at the combination of bari sarisha-11 and smi technique (v1s4) and lowest cgr (0.19 g plant−1 day−1) at the combination of bari sarisha-13 and broadcast sowing technique (v2s1) which was statistically similar (0.208 g plant−1 day−1) with v4s1 at 45-60 das. the highest cgr (1.178 g plant−1 day−1) was recorded at the combination of bari sarisha-13 and smi technique (v2s4). at 60-75, the highest cgr (0.884 g plant−1 day−1) was recorded at the sau sarisha-2 and smi technique (v4s4) combination. table 6. combined effect of variety and sowing technique on cgr (g plant−1 day−1) at 30-45, 45-60 and 60-75 das 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 c g r (g p la nt -1 d ay -1 ) variety 30-45 das 45-60 das 60-75 das 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 broadcasting line sowing raised bed smi c g r (g p la nt -1 d ay -1 ) sowing technique 30-45 das 45-60 das 60-75 das growth and yield performance of mustard and rapeseed by sowing techniques 94 treatments 30-45 das 45-60 das 60-75 das v1s1 0.309 ij 0.114 i 0.305 b-e v1s2 0.314 ij 0.934 c 0.259 c-e v1s3 0.898 c 0.522 e 0.334 b-e v1s4 1.242 a 1.061 b 0.321 b-e v2s1 0.190 k 0.199 g-i 0.084 e v2s2 0.348 hi 0.309 f 0.232 c-e v2s3 0.362 h 0.675 d 0.282 c-e v2s4 0.717 e 1.178 ah 0.374 b-e v3s1 0.305 j 0.117 i 0.117 de v3s2 0.306 ij 0.216 f-i 0.181 c-e v3s3 0.436 g 0.286 fg 0.433 b-d v3s4 0.836 d 0.865 c 0.492 bc v4s1 0.208 k 0.173 hi 0.262 c-e v4s2 0.276 j 0.270 f-h 0.637 ab v4s3 0.593 f 0.304 fg 0.635 ab v4s4 1.030 b 0.582 de 0.884 a cv (%) 4.8 13.2 55 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi effect of varieties and sowing techniques on relative growth rate relative growth rate (rgr) is the increase of materials per unit of plant materials per unit of time. relative growth rate was not significantly affected by variety at 30-45 das but was significant at 45-60 and 60-75 das (fig. 7). at 30-45 das, the highest rgr (0.161 g g−1 day−1) was recorded at bari sarisha-15, and the lowest rgr (0.15 g g−1 day−1 was recorded at sau sarisha-2. on 45-60 das, the highest rgr (0.052 g g−1 day−1) was recorded at bari sarisha-13. at 60-75 das, the highest rgr (0.035 g g−1 day−1) was recorded at sau sarisha-2. relative growth rate was significantly affected by the sowing techniques at 30-45 and 45-60 das but not significant at 60-75 das (fig. 7). at 30-45 das, the highest rgr (0.224 g g−1 day−1) was recorded both at the smi technique, and the lowest rgr (0.132 g g−1 day−1) at both at broadcast and line sowing technique, which was statistically similar (0.138 g g−1 day−1) with raised bed technique. on 45-60 and 60-75 das, the highest rgr (0.048 g g−1 day−1, 0.024 g g−1 day−1) was recorded at line sowing. fig. 7. effect of varieties and sowing techniques on rgr of mustard and rapeseed plants at different das. combined effect of varieties and sowing techniques on relative growth rate relative growth rate was significantly affected at 30-45 and 45-60 das but not significantly at 60-75 das, as shown in table 7. table 7. combined effect of variety and sowing technique on relative growth rate (g g−1 day−1) at 30-45, 45-60 and 60-75 das 0 0.05 0.1 0.15 0.2 0.25 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 r g r (g g -1 d ay -1 ) variety 30-45 das 45-60 das 60-75 das 0 0.05 0.1 0.15 0.2 0.25 broadcasting line sowing raised bed smi r g r (g g -1 d ay -1 ) sowing technique 30-45 das 45-60 das 60-75 das 95 aziz et al. treatments 30-45 das 45-60 das 60-75 das v1s1 0.144 b-d 0.019 g 0.029 b-d v1s2 0.098 f 0.079 a 0.012 d v1s3 0.146 b-d 0.028 fg 0.013 cd v1s4 0.234 a 0.040 cd 0.084 a v2s1 0.121 d-f 0.042 cd 0.012 d v2s2 0.170 b 0.039 c-e 0.019 cd v2s3 0.135 c-e 0.064 b 0.015 cd v2s4 0.210 a 0.063 b 0.012 d v3s1 0.158 bc 0.020 g 0.015 cd v3s2 0.140 b-d 0.033 d-f 0.018 cd v3s3 0.123 d-f 0.029 e-g 0.027 b-d v3s4 0.225 a 0.046 c 0.017 cd v4s1 0.106 ef 0.034 d-f 0.032 b-d v4s2 0.119 d-f 0.039 c-e 0.046 b v4s3 0.150 b-d 0.025 fg 0.033 bc v4s4 0.226 a 0.029 e-g 0.029 b-d cv (%) 12.4 14.5 56.3 here, v1= bari sarisha-11, v2= bari sarisha-13, v3= bari sarisha-15, v4= sau sarisha-2, s1= broadcasting, s2= line sowing, s3= raised bed, s4= smi at 30-45 das, the highest rgr (0.234 g g−1 day−1) was recorded at the combination of bari sarisha-11 and smi technique (v1s4) which was statistically similar to v2s4, v3s4, and v4s4. the lowest rgr (0.098 g g−1 day−1) was observed at the combination of bari sarisha-11 and line sowing (v1s2). at 45-60 das, the highest rgr (0.079 g g−1 day−1) was recorded at the combination of bari sarisha11 and line sowing (v1s2). at 60-75 das. the highest rgr (0.084 g g−1 day−1) was recorded at the combination of bari sarisha-11 and smi technique (v1s4) and the lowest rgr (0.012 g g−1 day−1) at the combination of bari sarisha-11 and broadcast technique (v1s4). effect of varieties and sowing techniques on shell yield, stover yield, seed yield according to fig. 8, all the yield parameters were affected significantly. the highest shell yield (2.62 t ha−1) was obtained at bari sarisha-13, and the lowest shell yield (1.01 t ha−1) at bari sarisha15. the highest shell yield (2.44 t ha−1) was obtained using smi techniques, and the lowest shell yield (1.38 t ha−1) by broadcast sowing techniques. akhter (2005) also reported same result.the highest stover yield (6.95 t ha−1) was obtained at bari sarisha-13, and the lowest stover yield (3.77 t ha−1) at bari sarisha-15. the highest stover yield (6.62 t ha−1) was obtained using the smi technique, and the lowest stover yield (3.72 t ha−1) was found using the broadcast sowing technique. the highest seed yield (3.74 t ha−1) was obtained at bari sarisha-11, and the lowest seed yield (2.54 t ha−1) at bari sarisha-15. the highest seed yield (3.8 t ha−1) was obtained using the smi technique, and the lowest seed yield (2.11 t ha−1) at broadcast sowing technique. fig. 8. effect of varieties and sowing techniques on shell, stover, and grain yield of mustard and rapeseed plants. 0 1 2 3 4 5 6 7 8 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 y ie ld (t h a1 ) variety shell yield stover yield grain yield 0 1 2 3 4 5 6 7 8 broadcasting line sowing raised bed smi y ie ld (t h a1 ) sowing technique shell yield stover yield grain yield growth and yield performance of mustard and rapeseed by sowing techniques 96 effect of varieties and sowing techniques on biological yield according to fig. 9, different varieties and sowing techniques significantly affected mustard and rapeseed plants' biological yield (t ha−1). the highest biological yield (12.8 t ha−1) was obtained at bari sarisha-11, and the lowest biological yield (7.32 t ha−1) at bari sarisha-15. the highest biological yield (12.86 t ha−1) was obtained using the smi technique, and the lowest biological yield (7.21 t ha−1) by broadcast sowing technique. khan et al. (2000) also reported by different sowing methods with similar result. fig. 9. effect of varieties and sowing techniques on biological yield of mustard and rapeseed plants. effect of varieties and sowing techniques on harvest index different varieties and sowing techniques significantly affected the harvest index (%) of mustard and rapeseed plants (fig. 10). the highest harvest index (34.84%) was observed at bari sarisha-15 and the lowest harvest index (28.04%) at bari sarisha-13. islam et al. (1994) also reported that varieties significantly affected the harvest index (%) of mustard. the highest harvest index (32.45%) was observed at line sowing and the lowest harvest index (29.43%) at broadcast sowing which was statistically similar (29.83%) to the smi technique. fig. 10. effect of varieties and sowing techniques on harvest index (%) of mustard and rapeseed plants. effect of varieties and sowing techniques on oil percentage the oil percentage of mustard and rapeseed plant seeds was significantly affected by varieties and sowing techniques. the highest oil percentage (40.65%) was obtained at bari sarisha-15 and the lowest (39.17%) was recorded at bari sarisha-11. the highest oil percentage (41.38%) was obtained at line sowing and the lowest (39.24%) at the raised bed technique. singh et al. (1999) also found oil content variation due to different varieties and sowing methods. 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 b io lo gi ca l y ie ld (t h a-1 ) 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 broadcasting line sowing raised bed smi b io lo gi ca l y ie ld (t h a-1 ) 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 h ar ve st in de x ( % ) 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 broadcasting line sowing raised bed smi h ar ve st in de x ( % ) 97 aziz et al. fig. 11. effect of varieties and sowing techniques on oil percentage (%) of mustard and rapeseed plants. conclusion the e life cycle of mustard var. bari sarisha-11 is longer, it showed better results in almost all the parameters. on the other hand, the system of mustard intensification (smi, s4) resulted in the best performance in almost every parameter followed by the raised bed (s3) sowing technique. from the findings it can be concluded that mustard var. bari sarisha-11 in the smi technique (s4) may be feasible if labour is not a problem in the raised beds. however, more trials need to be performed in different locations in bangladesh for better understanding and utilization. references ais (agricultural information service). 2010. krishi diary (in bangla). agricultural information service, dhaka. 13-14. akhter, s.m.m. 2005. effect of harvesting time on shattering, yield and oil content of rapeseed and mustard. m.s. thesis, sau, dhaka, bangladesh. bbs (bangladesh bureau of statistics). 2010. statistical year book of bangladesh. statistics division, ministry of planning, government of the people’s republic of bangladesh. bari oil research centre. 2001. annual report of 2000-2001. oilseed research centre, bangladesh agricultural research institute, joydebpur, gazipur. bharat, r., v. gupta, m. gupta and s. rai. 2022. effects of different sowing schedules and planting geometry on yield and productivity of brassica juncea l. bangladesh j. bot. 51(3): 631–635. davis, j.b., j.c. brown, d.j. wysocki and n. sirovatka. 2010. 2009-2010 pacific northwest winter canola variety trial. helgi library. 2023. which country produces the most mustard seeds? https://www.helgilibrary.com/charts/whichcountry-produces-the-most-mustard-seeds/ hossain, m.b., m.s. alam and m.a ripon. 2013. effect of irrigation and sowing method on yield and yield attributes of mustard. rajshahi univ. j. life earth agric. sci. 41: 65-70. hossain, m.f., a.k.m. zakaria and m.h. jahan. 1996. technical report on variety ccreening adaptive research oilseeds. rural development academy, bogra, bangladesh. pp. 6-34. islam, n., m. choudhury and m.r. karim. 1994. effects on sowing date on growth and development of mustard and rapes. progressive agric. 59: 23-29. jahan, m.h. and a.k.m. zakaria. 1997. growth and yield performance of different varieties of rapeseed, mustard and canola in level barind tract. progressive agric. 8(1&2): 144-152. khan, m.j., r.a. khattak and m.a. khan. 2000. influence of sowing methods on the productivity of canola grown in saline fields. pak. j. biol. sci. 3(4): 687-691. lyu, x., w. peng, w. yu, z. xin, s. niu and y. qu. 2021. sustainable intensification to coordinate agricultural efficiency and environmental protection: a systematic review based on metrological visualization. j. land use sci. 16(3): 313–338. mendham, n.j., j. russell and n.k. jarosz. 1990. response to sowing time of three contrasting australian cultivars of oilseed rape (brassica napus). j. agric. sci. cambridge. 114(3): 275-283. 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 bari sarisha-11 bari sarisha-13 bari sarisha-15 sau sarisha 2 o il p er ce nt ag e 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 broadcasting line sowing raised bed smi o il p er ce nt ag e growth and yield performance of mustard and rapeseed by sowing techniques 98 mendham, n.j., p.a. shipway and r.k. scott. 1981. the effect of delayed sowing and weather on growth, development and yield of winter oilseed rape (brassica napus). j. agric. sci. cambridge. 96: 389-416. pandit, t.k., s. roy and b. das. 2022. optimization of intra-row spacing for yield enhancement in system of mustard intensification (smi) techniques. int. j. bio-resource. stress manag. 13(11): 1170–1175. rahman, a., m.n. islam, s. fatima, m. rasal-monir, m. kirtania and k.u. ahamed. 2019. effect of different sowing methods and varieties on the yield of mustard (brassica campestris l.). int. j. adv. agric. sci. 4(10): 8-19. rahman, m.m. 2002. status of oilseeds and future prospects in bangladesh. paper presented in review workshop on the impact of technology transfer on oil crops, held at bari on 29 april 2002. rahman, m.m., m.u. salam, m.g. miah and m.s. islam. 1988. effect of sowing time on the performance of mustard (ss-75). bangladesh j. agric. res. 13(1): 47-51. shahbandeh, m. 2024. production of rapeseed by main producing countries 2023/24. statista. https://www.statista.com/statistics/263930/worldwide-production-of-rapeseed-by-country/ singh, s.p., b. singh, r. prakash, and d. pandry. 1999. a new approach to estimate of oil content in brassica. indian j. agric. sci. 9(9): 363-373. sushma, n., o. sampath, n.m. reddy and r.s. kumar. 2023. assessment of system of mustard intensification (smi) with plant geometry and age of the seedlings in enhancing growth and yield attributes of mustard (brassica juncea l.). int. j. environ. clim. change. 13(9): 2338–2346. thurling, n. 1974. morphophysiological determinants of yield in rapeseed (b. campestris and b. napus). ii. yield components. aust. j. agric. res. 25(5): 711-721. uddin, m.m., a. samad, m.r. khan, s. begum, k. hossain and s. khaleda. 1987. variety x sowing date combined in mustard and rapeseed. bangladesh j. agric. res. 12(2): 55-60. microsoft word 4. baj-470e bangladesh agron. j. 2024, 26(2): 27-33 determination of appropriate sowing date on fibre yield and yield attributes of jute (corchorus olitorius l.) var. bjri tossa pat-8 (robi-1) j. ferdous*, m. y. sarker and m. a. alim agronomy division, bangladesh jute research institute, dhaka, bangladesh *corresponding author, email: tanny.jannat92@gmail.com (received: 8 july 2023, accepted: 8 january 2024) keywords: tossa jute, yield, sowing date, robi-1 abstract the experiment was conducted at jute agriculture experimental station (jaes), manikganj; jrrs, rangpur and jrss, jashore to determine the optimum sowing date of jute var. bjri tossa pat-8. the experiment was laid-out in rcbd with three replications and variety o-9897 used as control. crops were sown on five different dates i.e., 20 march, 30 march, 10 april, 20 april and 30 april regarded as treatment. crops were attained recommended cultural practices and harvested at 120 days after sowing. the results showed that bjri tossa pat-8 (robi-1) sown on 10 april to 20 april gave significantly higher fibre and stick yields at manikganj (3.37 t ha−1 and 6.33 t ha−1 respectively); rangpur (3.11 t ha−1 and 5.22 t ha−1, respectively) and jashore (3.96 t ha−1 and 5.57 t ha−1, respectively) with an average 14% higher than control. introduction the agriculture climate of bangladesh is very much suitable for quality fibre production (islam and uddin, 2019). jute being the most important cash crop plays a major role in agriculture and economy of bangladesh. in 1970-80 decades about 15-16 lakh hectare of the total cultivable land was occupied by jute has been reduced to about 7.00 to 8.00 lakh hectare which produced about 16-17 lakh tons of fibre (ferdous and islam, 2018). however, national average yield is increased from 11.324 to 11.593 bale per hectare (bbs, 2022). currently, 85% of bangladesh’s yearly jute fibre output comes from tossa jute and the remaining 15% from white jute. the jute crop also greatly improves the soil fertility status by incorporating organic matter to the soil through decomposition of shaded leaves and plant residues and helps in breaking plough-pans through its long tap roots (ferdous et al., 2022). roughly some 5,000 tons of jute seeds are imported to bangladesh from india a year. however, national average yield is increased from 1.59 to 2.04 tons hectare−1. it is happened due to use of high yielding jute varieties and production technologies, which together contributed toward higher yield (bbs, 2015). bangladesh jute research institute (bjri) have successfully developed a new variety, which has a 20 % higher yield potential, finer and stronger fibre quality, and can be planted early in the season, thereby freeing up land seasonally for rice cultivation. however, to identify the optimum date of sowing for higher fibre yield for bjri tossa pat-8 at different agro-ecological zones of bangladesh. materials and methods the experiment was conducted at jute agriculture experimental station (jaes), manikganj; jute research regional station (jrrs), rangpur and jrss, jashore. the experiment was laid out in randomized complete block design (rcbd) with three replications. unit plot size was 4.0m×2.5m. jute var. bjri tossa pat-8 was used where var. o-9897 as control. crop was sown on four different dates viz., 30 march, 10 april, 20 april and 30 april as treatment varaibles. seeds were sown in line of 30 cm apart. other cultural and intercultural practices were followed as per bjri recommendation. plants were harvested at 120 days after sowing (das). location wise average data on fibre yield and quality attributing characters were analyzed with the help of computer statistical package (statistix 10). the 28 ferdous et al. mean differences among the treatments were adjusted by least significant difference (lsd) at 0.05 level (gomez and gomez, 1984). results and discussion results revealed all the yield contributing data like plant height, base diameter, fibre yield and stick yield were not differed significantly due to variety irrespective of sowing dates at jaes manikganj (table 1). bjri tossa pat-8 gave numerically higher fibre yield (2.98 t ha−1) and stick yield (6.51 t ha−1) over control variety o-9897 at manikganj. at rangpur, bjri tossa pat-8 recorded numerically higher fibre yield (3.33 t ha−1) over control variety o-9897 and comparatively higher stick yield was found in control. at sub-station, jashore, only plant population of those two varieties were differed significantly. bjri tossa pat-8 showed numerically higher fibre yield (3.28 t ha−1) and stick yield (8.67 t ha−1) over control var. o-9897 at jashore. hossain et al. (2015), islam and rahman (2008) were also reported the similar observations. table 1. effect of variety irrespective of date of sowing on fibre yield and yield components of tossa jute at different locations locations treatments plant population (m−2) plant height (m) base diameter (mm) fibre yield (t ha−1) stick yield (t ha−1) manikganj bjri tossa pat-8 26.5 3.17 15.01 2.98 6.51 o-9897 21.9 3.09 14.70 2.70 5.73 lsd(0.05) 0.16 0.12 0.77 0.55 1.25 cv (%) 6.96 3.71 4.91 8.53 2.91 rangpur bjri tossa pat-8 22.0 3.10 16.69 3.33 7.05 o-9897 18.7 3.03 16.16 3.09 7.34 lsd(0.05) 0.16 0.10 0.70 0.24 0.34 cv (%) 7.25 4.28 5.57 8.59 6.13 jashore bjri tossa pat-8 30.1 3.45 15.95 3.28 8.67 o-9897 27.4 3.30 16.19 3.02 7.31 lsd(0.05) 0.12 0.11 1.52 0.31 0.55 cv (%) 7.01 4.29 7.80 2.29 1.27 results showed that all the yield and yield contributing characters like plant population, base diameter, plant height and fibre yield were not significantly differed due to sowing date irrespective of variety at manikganj (table 2). bjri tossa pat-8 sown on 10 april gave the highest fibre and stick yields (3.23 t ha−1 and 6.47 t ha−1, respectively). plant height (3.52 m) and base diameter (18.73 mm) were also found the highest at the same date. all the yield and yield contributing characters like plant population, base diameter, fibre yield and stick yield were not significantly affected but only plant population was differed significantly due to sowing date irrespective of variety at rangpur (table 2). crops sown on 10 april gave the highest fibre and stick yield (2.67 t ha−1and 5.10 t ha−1, respectively). at jashore, all the yield and yield contributing characters like plant population, base diameter, fibre yield and stick yield were not significantly differ but, only plant population significant due to sowing date irrespective of variety (table 2). bjri tossa pat-8 sown on 20 april gave the highest fibre and stick yield (3.59 t ha−1 and 5.15 t ha−1, respectively). at this sowing date, plant height (3.79 m) and base diameter (18.77 mm) were also found the highest crop sown 10 april. the lowest fibre and stick yield (2.81 t ha−1 and 4.15 t ha−1 respectively) were obtained from the crop sown on 20 march. ferdous et al. (2022) also reported similar result. table 2. effect of date of sowing irrespective of variety on fibre yield and yield components of tossa jute at different locations determination of sowing date on fibre yield and yield attributes of jute 29 locations treatments plant population (m−2) plant height (m) base diameter (mm) fibre yield (t ha−1) stick yield (t ha−1) manikganj 30 march 19.32 3.16 14.76 2.48 5.29 10 april 25.40 2.97 16.56 2.62 5.86 20 april 24.90 3.52 18.73 3.23 6.47 30 april 22.15 3.18 15.88 2.29 4.98 lsd(0.05) 2.14 0.16 1.11 0.38 0.54 cv (%) 7.25 4.28 5.57 8.59 6.13 rangpur 30 march 17.03 3.05 15.59 2.25 3.98 10 april 21.07 3.33 16.74 2.60 4.59 20 april 24.35 3.72 20.44 2.67 5.10 30 april 19.70 3.39 17.44 2.10 4.85 lsd(0.05) 0.23 0.15 0.94 0.68 1.53 cv (%) 6.96 3.71 4.91 8.53 9.91 jashore 30 march 22.93 3.72 17.90 2.81 5.15 10 april 27.05 3.65 17.90 3.01 5.14 20 april 32.67 3.79 18.77 3.59 6.55 30 april 32.20 3.77 18.15 3.16 5.30 lsd(0.05) 1.71 0.18 1.52 0.50 0.86 cv (%) 7.01 4.29 7.80 2.29 1.27 it was observed that yield and yield contributing characters like plant population, base diameter and plant height were not differed significantly due to interaction of variety and sowing date at manikganj (table 3). plant height (3.53 m) and base diameter (18.86 mm) were found the highest at var. bjri tossa pat-8 on 10 april sowing. the lowest result was recorded from o-9897 sown on 30 march at manikganj. similar result was reported in ferdous et al. (2022) and hossain et al. (2015). table 3. interaction effect of variety and date of sowing on fibre yield and yield components of tossa jute at manikganj treatments plant population (m−2) plant height (m) base diameter (mm) v1 × s1 19.53 3.27 15.84 v1 × s2 21.93 3.18 15.22 v1 × s3 23.03 3.53 18.86 v1 × s4 20.70 3.24 15.63 v2 × s1 19.10 3.05 13.69 v2 × s2 28.87 2.76 17.90 v2 × s3 26.77 3.51 18.60 v2 × s4 23.60 3.13 16.13 lsd(0.05) 0.92 0.21 1.33 cv (%) 6.96 3.71 4.91 v1= bjri tossa pat-8 (robi-1), v2= o-9897, s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april it was observed that fibre yield and stick yield were differed significantly due to interaction of variety and sowing date at manikganj (fig. 1). bjri tossa pat-8 sown on 10 april gave the highest fibre and stick yield (3.37 t ha−1 and 6.33 t ha−1 respectively) at manikganj. the lowest fibre yield and stick yield (2.45 t ha−1 and 5.18 t ha−1 respectively) were recorded from o-9897 sown on 30 march at manikganj. 30 ferdous et al. fig. 1. interaction effect of variety and sowing date on yield of bjri tossa pat-8 (robi-1) at manikganj. here, v1= robi-1, v2= o-9897; s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april; fy = fibre yield, sy = stick yield. from the interaction table it was observed that yield and yield contributing characters like plant population, base diameter were not varied significantly due to interaction of variety and sowing date at rangpur (table 4). bjri tossa pat-8 sown on 10 april gave the highest plant height (3.58 m) and base diameter (20.41 mm) at rangpur which was followed by 20 april. the lowest data were recorded from the o-9897 sown on 20 march. similar observations were reported by alam et al. (1994), ferdous and islam (2018) and islam and alam (2019). table 4: interaction effect of variety and date of sowing on fibre yield and yield components of tossa jute at rangpur treatments plant population (m−2) plant height (m) base diameter (mm) v1 × s1 18.03 3.36 15.51 v1 × s2 23.33 2.95 16.37 v1 × s3 28.23 3.85 20.46 v1 × s4 20.93 3.82 17.84 v2 × s1 16.03 2.74 15.67 v2 × s2 18.80 3.70 17.11 v2 × s3 20.47 3.58 20.41 v2 × s4 18.47 2.96 17.04 lsd(0.05) 0.54 0.23 1.57 cv (%) 7.25 4.28 5.57 v1= bjri tossa pat-8 (robi-1), v2= o-9897; s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april from the interaction table it was found that fibre yield and stick yield were varied significantly due to interaction of variety and sowing date at rangpur (fig. 2). bjri tossa pat-8 sown on 10 april gave the highest fibre and stick yield (3.11 t ha−1 and 5.22 t ha−1, respectively) than control variety (2.23 t ha−1 and 4.97 t ha−1 respectively) at rangpur which was followed by 20 april. the lowest fibre yield and stick yield (2.26 t ha−1 and 3.95 t ha−1, respectively) were recorded from the o-9897 sown on 20 march. similar observations were reported by ferdous et al. (2022), alam et al. (1994), islam and rahman (2008) and islam and alam (2019). determination of sowing date on fibre yield and yield attributes of jute 31 fig. 2. interaction effect of variety and sowing date on fibre yield of bjri tossa pat-8 (robi-1) at rangpur. here, v1= bjri tossa pat-8 (robi-1), v2= o-9897; s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april; fy = fibre yield, sy = stick yield. at jashore, results showed that all the yield and yield contributing characters like plant population, base diameter significant at jashore (table 5). table 5: interaction effect of variety and date of sowing on fibre yield and yield components of tossa jute at jashore treatments plant population (m−2) plant height (m) base diameter (mm) v1 × s1 23.83 3.73 18.73 v1 × s2 28.77 3.71 18.47 v1 × s3 33.23 3.85 19.30 v1 × s4 32.43 3.82 18.90 v2 × s1 22.03 3.70 17.07 v2 × s2 25.33 3.58 17.33 v2 × s3 32.10 3.72 18.23 v2 × s4 31.97 3.72 17.40 lsd(0.05) 0.90 0.25 2.15 cv (%) 7.01 4.29 7.80 v1= bjri tossa pat-8 (robi-1), v2= o-9897; s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april bjri tossa pat-8 sown on 10 april gave the maximum plant height (3.85 m) and base diameter (19.30 mm) which was followed by 20 april. highest plant population was observed (33.23) in 20 april sowing and lowest from the o-9897 sown on 20 march. ferdous et al. (2022) and ferdous and islam (2018) reported similar findings on jute. at jashore, results showed that fibre yield and stick yield were not significantly changed at jashore (fig. 3.). bjri tossa pat-8 sown on 10 april gave the highest fibre and stick yield (3.96 t ha−1 and 5.57 t ha−1, respectively) than control variety (3.23 t ha−1 and 4.73 t ha−1 respectively) at jashore which was followed by 20 april. 0 1 2 3 4 5 6 v1 x s1 v1 x s2 v1 x s3 v1 x s4 v2 x s1 v2 x s2 v2 x s3 v2 x s4 yi el d (t ha −1 ) treatments fy (tha-1) sy (tha-1) 32 ferdous et al. fig. 3. interaction effect of variety and sowing date on fibre yield of bjri tossa pat-8 (robi-1) at jashore. here, v1=bjri tossa pat-8 (robi-1), v2= o-9897; s1= 30 march, s2= 10 april, s3= 20 april, s4= 30 april; fy = fibre yield, sy = stick yield. the lowest fibre yield and stick yield (2.47 t ha−1 and 4.10 t ha−1 respectively) were recorded from the o-9897 sown on 20 march. ferdous et al. (2022) and ferdous and islam (2018) reported similar findings on jute. conclusion yield and yield contributing characters like plant population and plant height, base diameter, fibre yield and stick yield were affected significantly due to sowing at different time. from the study, it can be concluded that the jute var. bjri tossa pat-8 (robi-1) gave fibre yield and stick yield, 14% higher than control when sown on 10 april to 20 april. references alam, m. a., j. ferdous, m.r. debnath, m.s. hossain and m.m. islam. 2019. reduction of production cost of jute (bjri tossa pat 5) as influenced by urea top dressing does and period. res. j. food nutr. 3(3):1-5. alam, m.m., a. karim, m.r.i. mondal, m.s. mondal and a.b.m. salauddin. 1994. effect of planting time and plant population on the yield of cotton. bangladesh j. jute fib. res. 19(1): 21-26. bbs. 2015. yearbook of agricultural statistics of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. bbs. 2022. yearbook of agricultural statistics of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. ferdous, j. and m.m. islam. 2018. off season seed yields of bjri tossa pat-7 and bjri tossa pat-5 as affected by sowing dates and locations. j. expt. biosci. 9(2): 55-63. ferdous, j., m.s. hossain, m.a. alim and m.m. islam. 2018. effect of field duration on yield and yield attributes of tossa jute varieties at different agro-ecological zones. bangladesh agron. j. 22(2): 77-82. ferdous, j., m.s. hossain, m.y. sarker, m.a. alim and m.m. islam. 2022. effect of sowing date on fibre yield and yield attributes of advanced breeding line o-0412-9-4 and o-043-7-9 of tossa jute (corchorus olitorius l.). bangladesh agron. j. 25(1): 1-6. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. 2nd edn. john wiley and sons inc., new york. pp. 304-307. hossain, m.s., m.m. islam, i. ahmed, m.s. rahman and m.l. rahman. 2015. effect of sowing dates on fibre yield and yield attributes of white jute breeding line bjc-5003 at different locations of bangladesh. int. j. sustain. agril. technol. 11(8): 01-06. islam, m.m. and a.t.m.m. alam. 2012. agronomic research and advancement in jute crop in bangladesh, (subtheme paper). souvenir, 11th conference on advances in agronomic research under changing environment in bangladesh. bangladesh agricultural research institute, gazipur, bangladesh. pp.101. 0 1 2 3 4 5 6 v1 x s1 v1 x s2 v1 x s3 v1 x s4 v2 x s1 v2 x s2 v2 x s3 v2 x s4 yi el d (t ha −1 ) treatments fy (tha-1) sy (tha-1) determination of sowing date on fibre yield and yield attributes of jute 33 islam, m.m. and m. rahman. 2008. in: hand book on agricultural technologies of jute, kenaf and mesta crops. bangladesh jute research institute, manik mia avenue, dhaka-1207, bangladesh. pp. 92. islam, m.m. and n. uddin. 2019. research and development advances of jute seed in bangladesh: a review. haya saudi j. life sci. 4(2): 52-68. bangladesh agron. j. 2023, 26(1): 122-127 yield performance of chia (salvia hispanica l.) in response to planting spacing and npk fertilizers md. moshiur rahman*, md. ariful haque and md. parvez anwar department of agronomy, bangladesh agricultural university, mymensingh, bangladesh *corresponding author, email: rahmanag63@bau.edu.bd (received: 17 june 2023, accepted: 03 october 2023) keywords: chia, plant population, plant height, seed yield, haulm yield and nutrient requirement abstract optimization of plant spacing, and fertilizer dose is very important for realizing maximum yield of a crop. an experiment was conducted at the agronomy field laboratory of bangladesh agricultural university, mymensingh during november 2020 to march 2021 to determine the effect of different spacing and npk fertilizer levels on yield and yield attributes of chia seed. the experiment consisted of four different spacing viz. 30 cm × 15 cm (s1), 30 cm × 30 cm (s2), 40 cm × 15 cm (s3) and 40 cm × 30 cm (s4) and five levels of npk fertilizer viz. no npk (f0), 30: 20: 25 kg npk ha-1 (f1), 60: 40: 50 kg npk ha-1 (f2), 90: 60: 75 kg npk ha-1 (f3) and 120: 80: 100 kg npk ha-1 (f4). the experiment was laid out in a factorial randomized complete block design (rcbd) with three replications. the results revealed that 40 cm × 30 cm spacing produced the highest number of inflorescences plant-1, seed yield and haulm yield. the fertilizer level 90: 60: 75 kg npk ha-1 showed the highest seed yield and haulm yield while 120:80 :100 kg npk ha-1 exhibited the maximum number of inflorescences plant-1. the combination of 30 cm ×30 cm spacing and 90: 60: 75 kg npk ha-1 produced the highest number of inflorescences plant-1 and seed yield whereas the combination of 40 cm × 30 cm spacing and 90: 60: 75 kg npk ha-1 had the highest haulm yield. the present study concluded that cultivation of chia at a spacing of 30 cm × 30 cm and fertilized with 90: 60: 75 kg npk ha-1 could be considered as the promising practice for reasonable seed yield. introduction malnourishment is a major problem in developing countries (mary et al., 2018a). this problem can be alleviated to some extent by increasing production and consumption of ‘super foods’. chia (salvia hispanica l.) is a new ‘super food crop’ in bangladesh which is a rich source of omega-3 fatty acid (α-linolenic acid), soluble and insoluble fibers and proteins in addition to other important nutritional components, such as vitamins, minerals and natural antioxidants. the seed is composed of protein (15%-25%), fats (30%-33%), carbohydrates (26%-41%), high dietary fiber (18%-30%), ash (4%-5%), dry matter (90%-93%), minerals (calcium, iron, magnesium, manganese, phosphorus, potassium, zinc etc.), vitamins (vitamin a, thiamine, riboflavin, niacin, vitamin c, vitamin e) and also contains a large number of antioxidants such as beta-carotene, tocopherol, chlorogenic acid, caffeic acid and flavonoids (ixtaina et al., 2008). chia seeds can be widely used in vegetarian and gluten-free diets. the seed has been considered as an important ingredient for human health and nutrition because of its high content of ω-3 fatty acid that promotes beneficial health effects (vuksan et al., 2010). chia is a short-day plant and is grown both in tropical and subtropical environments. the environmental conditions of bangladesh are suitable for cultivation of this new crop. before recommended for mass cultivation of the new crop, the optimization of different agronomic management practices is necessary for harvesting maximum yield. karim et. al. (2015) reported that november is the most suitable time for sowing of chia seed. however, information related to plant population, their spatial arrangement and nutrient requirement is highly scarce under response of chia to planting spacing and npk fertilizers 123 bangladesh condition. therefore, an experiment was undertaken to find out the optimal spacing and npk fertilizer doses for maximizing chia seed production. materials and methods the experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh, during november 2020 to march 2021. the experimental field is located at 24.75o n latitude and 90.50o e longitude and at an altitude of 18 m. the site belongs to the sonatola series of the old brahmaputra floodplain i.e agro-ecological zone-9 (aez-9). the experimental land was characterized by non-calcareous dark grey floodplain soils. the land was medium high and well drained with silty loam texture. the soil ph of the experimental site was 6.30 and the soil contained 1.35% organic matter. the experimental area is under the sub-tropical climate which is characterized by high temperature and heavy rainfall during kharif season (april to september) and scanty rainfall with moderately low temperature during rabi season (october to march). the overall relative humidity remains high during most part of the year except winter season. the experiment included 4 levels of planting spacing: 30 cm ×× 15 cm (s1), 30 cm × 30 cm (s2), 40 cm × 15 cm (s3) and 40 cm × 30 cm (s4) and 5 levels of npk fertilizers: no npk (f0), 30: 20: 25 kg npk ha-1 (f1 ), 60: 40: 50 kg npk ha-1 (f2 ), 90: 60: 75 kg npk ha-1 (f3), and 120: 80: 100 kg npk ha-1 (f4). the trial was conducted in a factorial randomized complete block design (rcbd) with three replications. the unit plot size was 3.0 m × 2.5 m. the experimental land was prepared with a power tiller and subsequently leveled by laddering. weeds and stubbles of the previous crop were collected and removed from the field as much as possible after leveling. the land was finally prepared, and the plots were laid out on 23 november 2020. the experimental plots were fertilized with nitrogen (n), phosphorus (p), potassium (k), sulphur (s), calcium (ca) and zinc (zn), respectively in the form of urea, triple superphosphate (tsp), muriate of potash (mop), gypsum and zinc sulphate as per experimental specification. moreover, each plot was equally treated with 15, 4 and 1.0 kg ha-1 s, ca and zn respectively to boost up the plant growth. all the fertilizers were applied at final land preparation, but urea was applied in three equal splits at final land preparation, 30 and 55 days after sowing (das). the seeds were sown on 24 november 2020 at spacings as per experimental treatments. the crops were infested with different weeds. weeds were removed manually from the experimental field two times i.e., at 25 das and at 40 das. to maintain the field at moist soil condition and for successful crop growth and development, irrigation was done once (1 january 2021) during the crop growth season. proper drainage was maintained to facilitate draining out of excess water from the plots. the infestations of insect-pests were negligible in the plots. however, fungus fighter (herbal fungicide) @ 10 ml 15l-1 and amistar top 325 sc (azoxystrobin + difenoconazole) @ 1.0 ml l-1 were applied on 16 january 2021 and 26 january 2021, respectively to prevent fungal diseases. the crop was harvested on 14 march 2021 as soon as the pretty purple flowers of the chia flower stalk started to dry and most of the petals had fallen off the flower. five plants (excluding border plants) were randomly selected and uprooted from each unit plot before harvesting for recording the necessary data on various plant characters and yield attributes. the harvested crops of each unit plot were bundled separately and properly tagged. after proper sun drying the yield of seed and straw of each unit plot was recorded and converted to ton per hectare (t ha-1). the collected data were compiled and tabulated in proper form and were subjected to statistical analysis by using a computer package program statistix10 and mean differences were adjudged by least significance difference (lsd) test. 124 rahman et al. results and discussion plant height the spacing had significant no significant effect on plant height (table 1) while npk fertilizer exerted significant effect (table 2). table 2 showed that the fertilizer level 90: 60: 75 kg npk ha-1 produced the tallest plant (111.08 cm) while no npk fertilizer showed the shortest plant (98.14 cm). it was also noted that the higher npk dose above 90: 60: 75 kg npk ha-1 reduced the plant height. the over application of fertilizer increased the interplant competition that reduced the plant height. it was further noted that the combined effect of spacing × npk fertilizer level were not significant for plant height of chia (table 3). table 1. effect of planting spacing on growth, yield and yield attributes of chia spacing plant height (cm) no. of main branches plant-1 no. of inflorescence plant-1 length of inflorescence (cm) 1000seeds weight (g) seed yield (t ha-1) haulm yield (t ha-1) s1 108.07 12.18 29.45 c 38.21 1.41 0.67 c 1.31 c s2 104.31 12.21 31.87 ab 35.55 1.45 0.70 bc 1.56 b s3 104.68 12.43 30.02 bc 38.36 1.42 0.74 b 1.70 a s4 100.78 12.51 33.55 a 37.61 1.43 0.81 a 1.72 a ls ns ns ** ns ns *** *** se (±) 2.75 0.35 1.06 1.22 0.03 0.02 0.04 cv (%) 7.22 7.74 9.28 8.93 5.11 9.47 8.24 in a column, the figures with same letter (s) or without letter do not differ significantly, whereas figures with dissimilar letter (s) differ significantly. ** = significant at 1 % level of probability, *** = significant at 0.1 % level of probability and ns = not significant. s1 = 30 cm ×× 15 cm, s2 = 30 cm ×× 30 cm, s3 = 40 cm ×× 15 cm, s4 = 40 cm × 30 cm table 2. effect of npk fertilizer on growth, yield and yield attributes of chia fertilizer plant height (cm) no. of main branches plant-1 no. of inflorescences plant-1 length of inflorescence (cm) 1000 seeds weight (g) seed yield (t ha-1) haulm yield (t ha-1) f0 98.14 c 12.20 27.85 d 35.92 1.41 0.55 c 1.05 d f1 101.52 c 12.21 30.11cd 37.15 1.43 0.60 c 1.47 c f2 103.55 bc 12.43 31.00 bc 36.62 1.40 0.74 b 1.61 b f3 111.08 a 12.92 33.33 ab 38.28 1.46 0.90 a 1.90 a f4 108.00 ab 11.85 33.83 a 39.20 1.45 0.84 a 1.82 a ls ** ns *** ns ns *** *** se (±) 3.08 0.39 1.18 1.37 0.03 0.02 0.05 cv (%) 7.22 7.74 9.28 8.93 5.11 9.47 8.24 in a column, the figures with same letter (s) or without letter do not differ significantly, whereas figures with dissimilar letter (s) differ significantly. ** = significant at 1 % level of probability, *** = significant at 0.1 % level of probability, ns = not significant. f0 = no npk, f1 = 30: 20: 25 kg npk ha-1, f2 = 60: 40: 50 kg npk ha-1. f3 = 90: 60: 75 kg npk ha-1, f4 = 120: 80: 100 kg npk ha-1 number of main branches plant-1 number of main branches plant-1 was not influenced by spacing, npk fertilizer levels and interaction of spacing and npk fertilizers. however, apparently, it was found that the number of branches plant-1 increased with the increase of fertilizer level. the fertilizer level 90: 60: 75 kg npk ha-1 resulted the highest number of branches plant-1 (table 2). number of inflorescences plant-1 the main effects of spacing and npk fertilizer levels as well as the interactions of spacing and npk fertilizers levels were significant on number of inflorescences plant-1. the highest number of inflorescences plant-1 (33.55) was recorded at a spacing of 40 cm × 30 cm and the lowest response of chia to planting spacing and npk fertilizers 125 (29.45) at 30 cm × 15 cm (table 1). the highest number of inflorescences plant-1 (33.83) was observed at the fertilizer level of 120: 80: 100 kg npk ha-1 (table 2). the result clearly showed that number of inflorescences plant-1 increased with the increase of fertilizer levels. the maximum number of inflorescences plant-1 (39.27) was recorded at 30 cm × 30 cm spacing fertilized with 90: 60: 75 kg npk ha-1 and the lowest (25.67) at the spacing of 30 cm × ×30 cm treated with no npk fertilizer (table 3). table 3. interaction effect of spacing and npk fertilizer on growth, yield and yield attributes of chia spacing ×fertilizer plant height (cm) no. of main branches plant-1 no. of inflorescences plant-1 length of inflorescence (cm) 1000 seeds weight (g) seed yield (t ha-1) haulm yield (t ha-1) s1×× f0 99.87 11.00 27.60 h-j 36.13 1.41 0.45 j 0.63 j s1 ××f1 105.07 12.40 28.60 g-j 37.13 1.47 0.50 ij 1.42 gh s1 ××f2 103.27 12.33 30.00 e-j 36.93 1.48 0.52 h-j 1.53 e-g s1 ××f3 118.87 13.00 35.40 a-d 40.00 1.48 0.60 g-i 1.64 c-f s1 ××f4 113.37 11.60 28.50 g-j 40.87 1.40 0.69 gh 1.76 b-d s2 ××f0 93.13 12.00 25.67 j 34.20 1.38 o.63 gh 0.84 j s2×× f1 99.87 12.53 30.67 b-g 32.53 1.39 0.79 d-f 1.43 f-h s2 × f2 104.80 12.40 32.60 d-i 36.13 1.43 0.88 b-d 1.58 d-g s2 × f3 113.20 12.60 39.27 a 36.80 1.43 1.04 a 1.72 b-e s2 × f4 113.87 12.60 36.00 a-c 38.07 1.45 0.89 b-d 1.82 bc s3 × f0 101.40 12.27 25.80 j 35.60 1.49 0.61 g-i 1.11 i s3 × f1 108.00 12.53 26.40 ij 3.87 1.41 0.69 fg 1.50 f-h s3 ××f2 109.07 12.47 29.70 e-i 38.93 1.33 0.78 d-f 1.73 b-e s3 × f3 101.20 12.60 33.80 b-f 39.53 1.40 0.91 bc 2.13 a s3 ××f4 103.73 11.57 31.53 c-h 39.87 1.50 0.81 c-e 1.85 bc s4 × f0 101.50 11.60 29.53 f-j 34. 47 1.37 0.63 gh 1.30 hi s4 × f1 89.80 12.73 29.93 e-j 38.33 1.42 0.75 ef 1.45 f-h s4 × f2 97.07 12.53 31.93 c-h 37.73 1.35 0.80 c-e 1.77 b-d s4 × f3 111.07 13.47 34.40 b-e 38.20 1.52 0.87 b-d 2.28 a s4 × f4 101.13 12.40 37.10 ab 39.33 1.47 0.97 ab 1.91 b ls ns ns *** ns ns *** *** se (±) 6.16 0.78 2.37 2.73 0.06 0.05 0.11 cv (%) 7.22 7.74 9.28 8.93 5.11 9.47 8.24 s1 = 30 cm × 15 cm, s2 = 30 cm × 30 cm, s3 = 40 cm × 15 cm, s4 = 40 cm × 30 cm, ls = level of significance, *** = significant at 0.1 % level of probability, ns = not significant f0 = no npk, f1 = 30: 20: 25 kg npk ha-1, f2 = 60: 40: 50 kg npk ha-1, f3 = 90: 60: 75 kg npk ha-1, f4 = 120: 80: 100 kg npk ha-1 the increased level of fertilizer helped in growth of plants and increased spacing offered less interplant competition that resulted in highest number of inflorescence plant-1 (mary et al., 2018b). length of inflorescence effect of spacing, npk fertilizer levels and their interactions were not significant for length of inflorescence. the spacing of 40 cm × 15 cm occupied the highest inflorescence length (38.36 cm) and the lowest inflorescence length (35.55 cm) was found at 30 cm × 30 cm spacing (table 1). numerically the highest inflorescence length (40.87 cm) was observed in the treatment combination of 30 cm × 15 cm spacing and fertilizer level of 120: 80: 100 kg npk ha-1 followed by fertilizer level of 90: 60: 75 kg npk ha-1 (table 3). 126 rahman et al. weight of 1000-seeds weight of 1000seeds did not vary significantly due to either main effect of spacing and npk fertilizer levels or their interaction. the maximum weight (1.52 g) of 1000-seeds was observed at 40 cm × 30 cm spacing fertilized with 90: 60: 75 kg npk ha-1 and the lowest weight (1.33 g) at 40 cm × 15 cm spacing fertilized with 60: 40: 50 kg npk ha-1 (table 3). mary et al. (2018a) reported that the weight of chia seeds was not affected for the interaction of spacing and fertilizer levels. seed yield seed yield was significantly influenced by spacing, npk fertilizer levels and interaction between spacing and npk fertilizer levels. in case of main effect of spacing, crops planted at a spacing of 40 cm × 30 cm resulted highest seed yield (0.81 t ha-1) and the lowest seed yield (0.67 t ha-1) at 30 cm × 15 cm spacing (table 1). table 2 showed that the maximum seed yield (0.90 t ha-1) was found at fertilizer level of 90: 60: 75 kg npk ha-1 which was statistically similar 120: 80: 100 kg npk ha-1 (0.84 t ha-1). the interaction effect showed the highest seed yield (1.04 t ha-1) at a spacing of 30 cm × 30 cm fertilized with 90: 60: 75 kg npk ha-1 (table 3). the highest spacing and fertilizer levels helped in more branching, inflorescences, leaves and total dry matter accumulation plant-1 which finally resulted into higher yield. the increase in seed yield at wider spacing was attributed to less intra plant competition and more space available for each plant that enhanced the plant growth and finally resulted into increasing the seed yield. mary et al. (2018b) also reported the highest seed yield at 60 cm×× 45 cm spacing with the fertilizer level of 90: 60: 75 kg npk ha-1 while mohanty et al. (2021) also found the highest seed yield at a spacing of 50 cm ××20 cm with 100 kg n ha-1. haulm yield haulm yield was significantly influenced by different spacing, npk fertilizer levels and interaction of different spacing and npk fertilizer levels. table 1 exhibited that the maximum haulm yield (1.72 t ha-1) was recorded at a spacing of 40 cm ×30 cm which was statistically similar with the spacing of 40 cm × 15 cm (1.70 t ha-1). table 2 revealed that the maximum haulm yield (1.90 t ha-1) was observed at the fertilizer level of 90: 60: 75 kg npk ha-1 which was statistically similar with the fertilizer level of 120: 80: 100 kg npk ha-1 (1.82 t ha-1). in table 3, it was found that the treatment combination of 40 cm ×30 cm spacing and fertilizer level of 90: 60: 75 kg npk ha-1 had the maximum haulm yield (2.28 t ha-1) which was at par with the combination of 40 cm × 15 cm spacing and the fertilizer level of 90: 60: 75 kg npk ha-1 (2.13 t ha-1). the combination of wider spacing and higher npk fertilizer levels resulted in less competition for nutrients that influenced the plant height and number of branches which resulted in higher haulm yield. mary et al. (2018a) was also found the maximum haulm yield at 60 cm × 45 cm spacing while interaction effect of spacing and fertilizer levels was non-significant in relation to haulm yield. the increase in haulm yield at wider spacing is attributed to less intra plant competition and more space was available which resulted into vigorous growth of the plants that translated into the increased haulm yield. conclusion the present result showed the highest seed yield of 1.04 t ha-1 at a spacing of 30 cm × 30 cm fertilized with 90: 60: 75 kg npk ha-1. the highest seed yield was obtained due to more branching, inflorescences and total dry matter accumulation plant-1. based on this study it may be concluded that cultivation at 30 cm × 30 cm spacing and the fertilized with 90: 60: 75 kg npk ha-1 could be considered as the promising practice for obtaining the highest seed yield of chia. response of chia to planting spacing and npk fertilizers 127 references ixtaina, v. y., s. m. nolasco and m. c. tomas. 2008. physical properties of chia (salvia hispanica l.) seeds. ins. crops prod. 8(3): 286-293. karim, m. m., m. ashrafuzzaman and m. a. hossain. (2015). effect of planting time on the growth and yield of chia (salvia hispanica l.). asian j. med. biol. res. 1(3): 502-507. mary, j., h. k. veeranna, g. k. girijesh, r. v. sreedhar, b. c. dhananjaya and s. gangaprasad. 2018a. effect of different spacings and fertilizer levels on growth parameters and yield of chia (salvia hispanica l.). inter. j. pure appl. biosci. 6(2): 259-263. mary, j., h. k. veeranna, g. k. girijesh, r. v. sreedhar, b. c. dhananjaya and s. gangaprasad. 2018b. effect of spacings and fertilizer levels on yield parameters, yield and quality of chia (salvia hispanica l.). j. pharmacol. phytochem. 3: 65-68. mohanty, p., c. umesha, d. r. sarangi and l. kumarsanodiya. 2021. impact of spacing and nitrogen levels on growth and yield of chia (salvia hispanica l.). biol. forum. 13(1): 149-153. vuksan, v., a. l. jenkins, a. g. dias, a. s. lee, e. jovanovski, a. l. rogovik and a. hanna. 2010. reduction in postprandial glucose excursion and prolongation of satiety: possible explanation of the long-term effects of whole grain salba (salvia hispanica l.). eur. j. clinical nutr. 64(4): 436-438. bangladesh agron. j. 2024, 27(1): 29-39 effect of different combinations of organic and inorganic fertilizer for maximizing yield and oil content of sunflower n.j. mim*, a.k.m.r. amin, t.s. roy and m.s. mony department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: nusratmim2649@gmail.com (received: 1 march 2025, accepted: 21 july 2025) keywords: bari surjumukhi-2, bari surjumukhi-3, vermicompost, fertilizer, oil content abstract an experiment was carried out at the agronomy field of sher-e-bangla agricultural university during the period from october 2021 to march 2022 with two factors, factor a: sunflower varieties(2): viz., v1= bari surjumukhi-2 and v2 = bari surjumukhi-3; and factor b: application of different combination of organic and inorganic manures (5): viz, f1= recommended dose of all chemical fertilizer (rdcf), f2= cowdung @ 10 t ha−1 + 75% of rdcf, f3= cowdung @ 10 t ha−1 + 50% of rdcf, f4= poultry litter @ 5 t ha−1 + 75% of rdcf, f5= poultry litter @ 5 t ha−1 + 50% of rdcf, f6= vermicompost @ 5 t ha−1 + 75% of rdcf and f7= vermicompost @ 5 t ha−1 + 50% of rdcf to investigate the effect of different combinations of organic and inorganic fertilizer for maximizing yield and oil content of sunflower. the experiment was followed the randomized complete block design (rcbd) with three replications. results indicated that sunflower var. bari surjumukhi-2 consistently outperformed bari surjumukhi-3. the interaction effects revealed that bari surjumukhi-2 interaction with vermicompost @ 5 t ha−1 + 75% of rdcf (v1f6) achieved the highest overall performance, with values such as head diameter (18.66 cm), number of seeds per head (437.23), 1000-seed weight (62.86 g), seed yield (2.87 t ha−1), stover yield (7.86 t ha−1), harvest index (26.82%), and seed oil content (40.77%). while the interaction of bari surjumukhi-3 with cowdung @ 10 t ha−1 + 50% of rdcf resulted in the lowest values. introduction sunflower (helianthus annuus l.) is an important oilseed crop cultivated globally for its high-quality edible oil and other industrial applications. in bangladesh, sunflower cultivation has gained popularity in recent years as a potential alternative to traditional oilseed crops like mustard and sesame. organic fertilizers, derived from plant or animal sources, have gained increasing attention in recent years due to their potential to improve soil health, enhance nutrient availability, and promote sustainable agricultural practices. these fertilizers are rich in organic matter and slowly release nutrients, providing a steady supply of essential elements throughout the crop's growth cycle (diacono and montemurro, 2010). organic sources contribute not only to the nutrient supply but also improve soil structure, water-holding capacity, and microbial activity, which can indirectly benefit plant growth and yield. studies have shown that the application of organic fertilizers could significantly enhance sunflower yield and oil content, particularly in nutrient-depleted soils (jat et al., 2018). inorganic or synthetic fertilizers are formulated to provide readily available forms of essential nutrients, such as nitrogen, phosphorus, and potassium, to the plants. these fertilizers are often preferred for their consistent nutrient composition and their ability to deliver a quick nutrient boost to the crop during critical growth stages (mirshekari et al., 2022). in sunflower production, nitrogen is particularly important for vegetative growth and biomass accumulation, while phosphorus plays a vital role in root development, flowering, and seed formation. potassium, on the other hand, enhances drought tolerance, disease resistance, and oil quality 30 mim et al. (abbas et al., 2021). the judicious application of inorganic fertilizers, considering the specific nutrient requirements of sunflower varieties, can significantly improve yield and oil content. however, excessive or imbalanced application of inorganic fertilizers can lead to environmental concerns, such as nutrient leaching and soil degradation (guo et al., 2020). the integration of organic and inorganic fertilizers, known as integrated nutrient management (inm), has been recognized as an effective approach to optimize crop productivity while maintaining soil health and environmental sustainability. the combined application of these fertilizers can provide a balanced supply of nutrients, leveraging the benefits of both organic and inorganic sources (ghosh et al., 2021). organic fertilizers contribute to soil fertility and structure, while inorganic fertilizers provide readily available nutrients to meet the immediate nutrient demands of the crop. the synergistic effect of this combination could lead to improved nutrient use efficiency, enhanced soil microbial activity, and better crop performance (rezaei et al., 2021). materials and methods the experiment was conducted at the research field of sher-e-bangla agricultural university, dhaka under the agroecological zone of modhupur tract, aez-28 during the rabi season from october to march 2022. the climate of the experimental site was subtropical, characterized by the winter season from november to february, and the pre-monsoon period from march to april, and the monsoon period from may to october (edris et al., 1979). the experiment was laid out in a randomized complete block design (rcbd) with three replications. there were two factors viz., factor a: sunflower varieties-2 (v1 = bari surjumukhi-2 and v2 = bari surjumukhi-3) and factor b: application of different combination of organic and inorganic manures-5 (f1= recommended dose of all chemical fertilizer (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf the organic fertilizer doses were applied during the final land preparation for uniform distribution and incorporation into soil. for the inorganic fertilizers, the recommended dose of 60:90:60 kg of nitrogen (n), phosphorus oxide (p₂o₅), and potassium oxide (k₂o) per hectare was applied in the form of urea, triple superphosphate (tsp), and muriate of potash, respectively. the application of inorganic fertilizers was split into two doses. the first dose, 50% nitrogen (n) and full doses of phosphorus (p) and potassium (k) was applied at sowing time. the remaining 50% nitrogen was top-dressed 30 days after sowing (das). sowing of seed was done manually by line sowing on 12th october 2022 using a seed rate of 8-10 kg ha−1 by dibbling two seeds at each hill to a depth of 3 cm by maintaining the spacing at 60 cm × 30 cm at each. all intercultural operations like gap filling, hand weeding, irrigation, and plant protection measures were taken properly. plant height (cm), dry weight plant−1 (g), head diameter (cm), number of seed head−1, 1000-seed weight (g), seed yield (t ha−1), stover yield (t ha−1), harvest index (t ha−1), oil content (%) were recorded during the experiment. the harvest index was calculated with the following formula: harvest index (%) = 𝐺𝑟𝑎𝑖𝑛 𝑌𝑖𝑒𝑙𝑑 𝐵𝑖𝑜𝑙𝑜𝑔𝑖𝑐𝑎𝑙 𝑌𝑖𝑒𝑙𝑑 × 100% the data were analyzed and the means were separated by least significant difference (lsd) at 5% level of probability using the statistix 10 data analysis software. results and discussion plant height the plant height of the sunflower was significantly influenced by the integration of different doses of organic and inorganic fertilizer (fig. 1). effect of organic and inorganic fertilizer for maximizing yield and oil content of sunflower 31 fig. 1. effect of integration of organic and inorganic fertilizer on plant height at different das of sunflower. here, f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. lsd (0.05) = 1.75, 4.57, 5.97, 7.64, and 6.96 at 25, 45, 65, and 85 das at harvest, respectively. experimental findings revealed that the maximum plant height of sunflower (28.07, 70.56, 123.29, 130.25, and 127.26 cm) at 25, 45, 65, 85 das, and at harvest, respectively, was observed in the f6 (vermicompost @ 5 t ha−1 + 75% of rdcf) treatment, which was statistically similar to the f4 (26.84, 67.33, 120.57, 127.40, and 124.23 cm) at the same growth stages. in contrast, the lowest plant height of was observed in the f3 (cowdung @ 10 t ha−1 + 50% of rdcf) treatment, which was statistically similar to f5. table 1. interaction effect of variety and integration of organic and inorganic fertilizer on plant height of sunflower on different das interaction plant height (cm) 25 das 45 das 65 das 85 das at harvest v1 × f1 24.70 c-e 68.63 b-d 122.50 cd 131.35 bc 127.35 cd v1 × f2 26.89 bc 70.15 bc 125.01 bc 132.12 bc 130.85 bc v1 × f3 22.38 ef 61.54 ef 111.18 ef 126.55 cd 115.18 e-g v1 × f4 28.22 ab 74.50 ab 132.42 ab 140.60 ab 138.73 ab v1 × f5 24.67 c-e 64.57 c-e 113.37 e 127.75 cd 120.28 d-f v1 × f6 29.90 a 78.06 a 133.59 a 143.25 a 142.35 a v1 × f7 23.81 d-f 64.63 c-e 115.52 de 129.80 bc 122.97 c-e v2 × f1 22.66 ef 54.75 gh 101.98 h-i 105.75 fg 101.63 i-k v2 × f2 24.45 c-e 56.09 f-h 103.61 f-h 107.52 e-g 104.73 h-j v2 × f3 18.45 h 49.80 h 93.72 i 94.30 h 90.17 l v2 × f4 25.45 cd 60.16 e-g 108.71 e-g 114.20 ef 109.73 g-i v2 × f5 19.79 gh 50.85 h 95.88 hi 97.15 gh 94.60 k-l v2 × f6 26.25 b-d 63.05 de 112.98 e 117.25 de 112.16 f-h v2 × f7 21.70 fg 52.02 h 98.07 hi 103.58 f-h 96.65 j-l lsd (0.05) 2.47 4.46 8.44 10.80 9.84 cv (%) 6.08 6.21 4.39 5.39 5.11 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. here, v1 = bari surjumukhi 2 and v2 = bari surjumukhi 3; and f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. 0 20 40 60 80 100 120 140 25 45 65 85 at harvest p la n t h e ig h t (c m ) days after sowing (das) f1 f2 f3 f4 f5 f6 f7 32 mim et al. combining vermicompost with 75% rdcf provides an initial nutrient boost from chemical fertilizers for rapid growth, while vermicompost ensures sustained nutrient release. this approach enhances root development, nutrient uptake, and photosynthesis, leading to taller, more vigorous sunflower plants compared to using chemical or organic fertilizers alone. interaction effect of variety and integration of organic and inorganic fertilizer the plant height of sunflowers was significantly influenced on different das due to the interaction (table 1). experimental results showed that the maximum plant height (29.90, 78.06, 133.59, 143.25, and 142.35 cm) was observed in the v1f6 interaction treatment at 25, 45, 65, and 85 das which was statistically similar to v1f4 (28.22, 74.50, 132.42, 140.60 and 138.73cm) at the same intervals, including harvest. on the other hand, the v2f3 treatment recorded the lowest plant height. leaf area the integration of different doses of organic and inorganic fertilizers significantly affects leaf area (table 2). the experimental findings revealed that at 25, 40, 55, and 70 das, the maximum leaf area (3306.7, 14691, 22003, and 31852 mm) was observed in the v1f6 treatment, which was statistically similar to the v1f4. applying 5 t ha−1 vermicompost with 75% rdcf enhances sunflower leaf area by combining gradual nutrient release with readily available fertilizers. this synergy supports continuous nutrient supply, promoting growth and yield. a similar result was also observed by gahlot and singh (2023), who reported that the integrated use of vermicompost and chemical fertilizers significantly influenced the leaf area of sunflowers. on the other hand, the v2f3 interaction treatment recorded the lowest leaf area followed by v2f5 and v2f7 at the same intervals. table 2. interaction effect of variety and integration of organic and inorganic fertilizer on leaf area on different das of sunflower interaction leaf area plant−1 (mm2) at 25 das 40 das 55 das 70 das v1 × f1 2793.2 b 12755 cd 19005 cd 28732 c v1 × f2 2793.0 b 13072 b-d 19527 b-d 29174 bc v1 × f3 2318.5 de 11850 de 17914 c-e 25972 de v1 × f4 3222.6 a 14162 ab 21265 ab 31319 ab v1 × f5 2604.3 b-d 12018 c-e 17959 c-e 26879 cd v1 × f6 3306.7 a 14691 a 22003 a 31852 a v1 × f7 2785.0 bc 12365 c-e 18307 c-e 27175 cd v2 × f1 2567.2 b-e 11981 de 17904 c-e 20475 hi v2 × f2 2607.5 b-d 12315 c-e 18179 c-e 21503 gh v2 × f3 2248.2 e 11122 e 16572 e 18932 i v2 × f4 2787.7 bc 12773 cd 19252 cd 23377 fg v2 × f5 2365.6 de 11299 e 17020 e 18466 i v2 × f6 2831.3 b 13279 bc 19720 bc 24091 ef v2 × f7 2466.3 c-e 11868 de 17681 de 19310 hi lsd (0.05) 325.15 1269.70 1906.30 2498.50 cv (%) 7.19 6.03 6.06 6.00 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. here, v1 = bari surjumukhi 2 and v2 = bari surjumukhi 3; and f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. dry weight of plant dry weight per plant varies due to different growth stages showed significant influence on different das, affected by different doses of organic and inorganic fertilizer (table 3). based on the experimental findings discovered that the v1f6 exhibited the highest dry weight per plant effect of organic and inorganic fertilizer for maximizing yield and oil content of sunflower 33 (1.31, 19.85, 44.53, and 238.16 g) at 25, 50, 75, das and at harvest respectively. the result was consistent with the research conducted by gahlot and singh (2023). in contrast, the v2f3 interaction treatment resulted in the lowest dry weight per plant (which was statistically similar to the v2f5. table 3. interaction effect of variety and integration of organic and inorganic fertilizer on dry weight plant−1 at different das of sunflower interaction dry weight plant−1 (g) 25 das 50 das 75 das at harvest v1 × f1 1.04 cd 12.83 de 39.32 cd 210.36 b-d v1 × f2 1.08 c 14.19 cd 40.08 bc 214.28 bc v1 × f3 0.90 e 11.17 ef 33.28 e 201.38 c-f v1 × f4 1.14 bc 16.95 b 43.36 ab 224.26 ab v1 × f5 0.94 de 11.01 fg 35.20 e 204.30 c-f v1 × f6 1.31 a 19.85 a 44.53 a 238.16 a v1 × f7 0.97 de 12.31 ef 36.40 c-e 207.28 b-e v2 × f1 0.74 f 10.72 f-h 27.14 gh 188.65 e-h v2 × f2 0.93 e 11.57 ef 29.30 fg 191.32 d-h v2 × f3 0.54 h 7.93 i 24.10 h 174.39 h v2 × f4 1.09 c 14.70 c 32.91 ef 194.25 d-g v2 × f5 0.63 gh 9.16 hi 25.45 gh 180.56 gh v2 × f6 1.21 ab 16.57 b 35.57 de 199.26 c-g v2 × f7 0.67 fg 10.02 gh 26.34 gh 185.70 f-h lsd (0.05) 0.10 1.72 3.89 19.20 cv (%) 6.33 8.03 6.86 5.69 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. here, v1 = bari surjumukhi 2 and v2 = bari surjumukhi 3; and f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. head diameter variation in head diameter among sunflower varieties is attributed to their genetic composition. the integration of different sunflower varieties and the application of varying amounts of organic and inorganic fertilizers have shown significant impacts on the head diameter of sunflowers (table 4). the maximum head diameter of sunflower (18.66 cm) was observed from the v1f6 which was statistically similar to the v1f4 (18.03 cm). in contrast, the v2f3 treatment recorded the lowest head diameter (13.15 cm). integrating vermicompost with chemical fertilizers provides balanced nutrients, including n, p, and k, throughout sunflower growth. vermicompost releases these essential nutrients gradually, while chemical fertilizers support early growth. this continuous supply enhances flower bud initiation, pollination, and seed set, leading to larger heads. vermicompost also improves soil structure, further boosting nutrient uptake and head development. this approach results in larger head diameters compared to using only organic or inorganic fertilizers. this is quite similar to the findings of umar et al. (2017) who found that a 50:50 ratio of vermicompost and npk increased head diameter, and seed weight head−1 of sunflower. number of seeds per head the integrated use of various dosages of organic and inorganic fertilizer also had a significant impact on the number of seeds per sunflower head (fig. 2). the highest number of seeds per head (412.50) was observed from the f6 treated plot whereas the lowest number of seeds head−1 (273.21) was observed from the f3 treated plot. 34 mim et al. fig. 2. effect of integration of organic and inorganic fertilizer on the number of seeds head−1 of sunflower (lsd (0.05) = 26.90). here, f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. interaction effect of variety and integration of organic and inorganic fertilizer the number of seeds head−1 of sunflower was significantly affected by the integration of different sunflower varieties and the application of varying amounts of organic and inorganic fertilizer (table 4). the interaction treatment v1f6 resulted in the maximum number of seeds head−1 (437.23), which was statistically similar to the v1f4 (412.15) and the lowest number of seeds head−1 (242.29) from the v2f3 interaction treatment. weight of 1000 seeds the weight of 1000 sunflower seeds varied significantly across different sunflower varieties. the integrated use of organic and inorganic fertilizers significantly affected 1000seed weight (fig. 3). the maximum weight (59.98 g) was recorded in the f6 treated plot, which was statistically similar to the f4 (59.48 g) plot. the lowest weight (52.91 g) was observed in the f3 treated plot, similar to f5 (53.89 g) plot. a similar result was reported by jayaprakash et al. (2011) who found that the application of 5 t ha−1 vermicompost + 75% npk recorded the highest growth, yield attributes, and seed yield compared to other treatments. fig. 3. effect of integration of organic and inorganic fertilizer on weight of 100 seeds of sunflower (lsd (0.05) = 3.40). here, f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. 0 50 100 150 200 250 300 350 400 450 f1 f2 f3 f4 f5 f6 f7 n u m b e r o f se e d s h e a d -1 integration of organic and inorganic fertilizer 48 50 52 54 56 58 60 62 f1 f2 f3 f4 f5 f6 f7 w e ig h t o f 1 0 0 0 s e e d s (g ) integration of organic and inorganic fertilizer effect of organic and inorganic fertilizer for maximizing yield and oil content of sunflower 35 interaction effect of variety and integration of organic and inorganic fertilizer the weight of 1000 -seeds of sunflower was significantly affected by the integration of different sunflower varieties and the application of varying amounts of organic and inorganic fertilizer (table 4). the interaction treatment v1f6 resulted in the maximum weight of 1000 seeds of sunflower (62.86 g) which was statistically similar to the v1f4 (62.23 g) and v1f2 (60.10 g) whereas the lowest weight of 1000seeds of sunflower (49.51g) from the v2f3 interaction treatment which was statistically similar to the v2f5 (50.67 g). table 4. interaction effect of variety and integration of organic and inorganic fertilizer on head diameter, number of seeds head−1, and weight of 1000seeds of sunflower interaction head diameter (cm) no. seeds head−1 weight of 1000 seed (g) v1 × f1 15.98 c-e 362.28 c-e 58.36 a-d v1 × f2 16.42 bc 382.35 b-d 60.10 a-c v1 × f3 14.25 d-g 304.12 gh 56.31 c-f v1 × f4 18.03 ab 412.15 ab 62.23 ab v1 × f5 14.85 c-g 338.44 e-f 57.10 c-f v1 × f6 18.66 a 437.23 a 62.86 a v1 × f7 15.07 c-g 346.53 d-f 57.65 b-e v2 × f1 15.05 c-g 308.27 gh 53.13 e-h v2 × f2 14.97 c-g 319.56 fg 54.49 d-g v2 × f3 13.15 g 242.29 i 49.51 h v2 × f4 15.50 c-f 353.33 c-f 56.73 c-f v2 × f5 13.78 fg 265.26 i 50.67 gh v2 × f6 16.25 b-d 387.77 bc 57.10 c-f v2 × f7 14.10 e-g 272.65 hi 52.37 f-h lsd (0.05) 2.04 38.04 4.812 cv (%) 7,89 6.71 5.09 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. here, v1 = bari surjumukhi 2 and v2 = bari surjumukhi 3; and f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. seed yield the cultivation of different sunflower varieties significantly influences seed yield. the integration of organic and inorganic fertilizers at varying rates also significantly impacted sunflower seed yield (fig. 4). the experimental results showed that the f6 treated plot recorded the maximum seed yield (2.55 t ha−1), which was statistically similar to plots treated with f4 (2.43 t ha−1). conversely, the lowest seed yield (1.52 t ha−1) was observed in the f3 treated plot, which was statistically similar to plots treated with f5 (1.56 t ha−1). vermicompost supplies n, p, and k gradually, supporting growth, flowering, and seed development, whereas chemical fertilizers ensure an immediate supply of these nutrients. their integration ensures a continuous nutrient supply, enhances soil structure, and boosts yield by supporting optimal plant growth and seed filling. the results align with the findings of ahmad et al. (2018) who reported that integrated use of vermicompost (5 t ha−1) and 75% recommended npk increased sunflower seed yield by 35% over the control while also improving soil properties like organic carbon, available n, p and k status. 36 mim et al. fig. 4. effect of integration of organic and inorganic fertilizer on seed yield of sunflower (lsd (0.05) = 0.15). here, f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. interaction effect of variety and integration of organic and inorganic fertilizer the seed yield of sunflower was significantly affected by the integration of different sunflower varieties and the application of varying amounts of organic and inorganic fertilizer (table 5). the experimental findings indicate that the v1f6 interaction treatment resulted in the maximum seed yield of sunflower (2.87 t ha−1) which was statistically similar to the v1f4 (2.76 t ha−1) interaction treatment. whereas the lowest seed of sunflower (1.31 t ha−1) was observed from the v2f3 which was statistically similar with the v2f5 (1.43 t ha−1), and v2f7 (1.52 t ha−1) interaction treatment. stover yield the v1f6 interaction treatment resulted in the maximum stover yield of sunflower (7.86 t ha−1) which was statistically similar to the v1f4 (7.79 t ha−1), v1f1 (7.55 t ha−1) and v1f2 (7.56 t ha−1) interaction treatment (table 5). whereas the lowest stover yield of sunflower (5.17 t ha−1) was observed from the v2f3 which was statistically similar to the v2f5 (5.36 t ha−1) and v2f7 (5.65 t ha−1) interaction treatment. harvest index the experimental result indicated that the plot treated with f6 treatment had the maximum harvest index (25.67 %) of sunflower (fig. 5) followed by f4 (25.11%) for the harvest index of sunflowers. the lowest harvest index (21.55 %) was observed with f3 treatment which was statistically similar to the f5 (21.81%) and f7 (22.20 %) treatment. 0 0.5 1 1.5 2 2.5 3 f1 f2 f3 f4 f5 f6 f7 s e e d y ie ld ( t h a − 1 ) integration of organic and inorganic fertilizer effect of organic and inorganic fertilizer for maximizing yield and oil content of sunflower 37 fig. 5. effect of integration of organic and inorganic fertilizer on harvest index of sunflower (lsd (0.05) = 1.43). here, f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. oil content (%) cultivation of different varieties of sunflower along with the integration of organic and inorganic fertilizers had shown a non-significant impact on the oil content of sunflower (table 5). the more nitrogen supply is available, the more seed yields are abundant but with less oil content. table 5. interaction effect of variety and integration of organic and inorganic fertilizer on yield attributes, yield, harvest index and oil content of sunflower interaction seed yield (t ha−1) stover yield (t ha−1) harvest index (%) oil content (%) v1 × f1 2.37 bc 7.55 ab 24.05 c-e 39.93 v1 × f2 2.43 b 7.56 ab 24.32 b-d 40.02 v1 × f3 1.73 ef 6.11 e-g 22.08 e-g 38.78 v1 × f4 2.76 a 7.79 a 26.15 ab 40.56 v1 × f5 1.69 ef 6.04 fg 22.56 c-g 38.91 v1 × f6 2.87 a 7.86 a 26.82 a 40.77 v1 × f7 2.19 cd 7.25 bc 23.18 c-f 39.08 v2 × f1 1.77 e 6.23 ef 22.02 fg 39.00 v2 × f2 1.82 e 6.29 ef 22.45 d-g 39.33 v2 × f3 1.31 g 5.17 h 21.02 g 38.35 v2 × f4 2.10 d 6.63 de 24.06 c-e 39.93 v2 × f5 1.43 g 5.36 h 21.05 g 38.78 v2 × f6 2.22 b-d 6.83 cd 24.52 bc 40.18 v2 × f7 1.52 fg 5.65 gh 21.21 fg 38.90 lsd (0.05) 0.22 0.52 2.03 ns cv (%) 6.45 4.73 5.19 3.68 in a column means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 5% level of significance. here, v1 = bari surjumukhi 2 and v2 = bari surjumukhi 3; and f1 = recommended dose of all chemical fertilizers (rdcf), f2 = cowdung @ 10 t ha−1 + 75% of rdcf, f3 = cowdung @ 10 t ha−1 + 50% of rdcf, f4 = poultry litter @ 5 t ha−1 + 75% of rdcf, f5 = poultry litter @ 5 t ha−1 + 50% of rdcf, f6 = vermicompost @ 5 t ha−1 + 75% of rdcf and f7 = vermicompost @ 5 t ha−1 + 50% of rdcf. 19 20 21 22 23 24 25 26 f1 f2 f3 f4 f5 f6 f7 h a rv e st i n d e x ( % ) integration of organic and inorganic fertilizer 38 mim et al. conclusion considering the above results, it may be concluded that sunflower var. bari surjumukhi-2 variety consistently outyielded bari surjumukhi-3 in terms of plant height, leaf area, dry weight, head diameter, number of seeds head−1, weight of 1000 seeds, seed yield, stover yield, harvest index, and seed oil content (40.77%). the interaction effects highlighted that bari surjumukhi-2 combined with vermicompost at 5 t ha−1 + 75% of the recommended dose of chemical fertilizers (v1f6) achieved the highest values with a head diameter (13.15 cm), number of seeds head−1 (242.29), weight of 1000 seeds (49.51 g), seed yield (1.31 t ha−1), stover yield (5.17 t ha−1), harvest index (21.02 %) and seed oil content (38.35%). references abbas, g., z. hussain, b. fatima, a. rehman, m.a. khan and m. habib-ur-rahman. 2021. impact of integrated nutrient management on productivity and quality of spring planted sunflower (helianthus annuus l.). agron. 11(5): 1011. abd, s.a., k.a. jassem and b.m. mohsen. 2019. response of four sunflower genotype (helianthus annuus l.) to different planting dates. j. al-muthanna agric. sci. 7(2): 98-105. ahmad, w., m.a. noor, r. sayyed, a. iqbal, e.e. valeem and s. ahmed. 2018. potential utilization of marginal resources for sustainable sunflower production in salt-affected environments. environ. sci. poll. res. 25: 19866-19884. ali, h., h.a. randhawa and m. yousaf. 2004. quantitative and qualitative traits of sunflower (helianthus annuus l.) as influenced by planting dates and nitrogen application. int. j. agric. biol. 6(2): 410412. ali, a. and s. ullah. 2012. effect of nitrogen on achene protein, oil, fatty acid profile, and yield of sunflower hybrids. chil. j. agric. res. 72: 564–7. awoke, t. and t. anteneh. 2022. evaluation of sunflower (helianthus annuus l.) varieties for growth, yield and yield components under irrigation at lowland area of south omo zone, southern ethiopia. j. agric. aquac. 4(2): 1-6. bakht, j., s. ahmad, m. tariq, h. akbar and m. shafi. 2006. performance of various hybrids of sunflower in peshawar valley. j. agri. sci. 3: 25-29. diacono, m. and f. montemurro. 2010. long-term effects of organic amendments on soil fertility: a review. agron. sust. develop. 30(2): 401-422. edris, k.m., a.m.t. islam, m.s. chowdhury and a.k.m.m. haque. 1979. detailed soil survey of bangladesh. dept. soil survey, bau and govt. people's republic of bangladesh. pp. 118. gahlot, k. and a. singh. 2023. a sustainable approach: effect of integrated nutrient management practices on growth, phenology and yield of sunflower (helianthus annuus l.). j. food chem. nanotech. 9(1): 80-90. ghosh, a., d.s. rana, r. islam and m.a. hossain. 2021. integrated nutrient management for sustaining soil health and crop production in south asia. plant nutri. food prod. 1: 93-128. guo, j.k., x.b. feng, x.y. chen, d.z. wu, c.y. chu, j. yuan and z.q. ye. 2020. effects of nitrogen fertilizer application rates on nitrate distribution in soil profile and sunflower nitrogen utilization. agric. 10(3): 95. hossain, m.k., m.m. islam, a.a. mamun and s.m.a.a. mamun. 2018. performance of sunflower genotypes in non-saline and saline soils of southern bangladesh. bangladesh agron. j. 21(1): 17. hussain, s., f. khan, h. hussain and l. nie. 2016. physiological and biochemical mechanisms of seed priming-induced chilling tolerance in rice cultivars. front. plant sci. 7: 1-7. islam, m.a., s. islam, a. akter, m.h. rahman and d. nandwani. 2021. effect of organic and inorganic fertilizers on soil properties and the productivity of sunflower–mungbean–rice cropping pattern. agric. 11(3): 217. jat, r.a., h.n. meena, a.l. singh, j.n. surya and b.l. gajja. 2018. effects of organic and inorganic fertilizers on yield, oil content and nutrient balances in sunflower (helianthus annuus l.) in sunflower-based cropping systems. commun. soil sci. plant analy. 49(16): 2005-2018. jayaprakash, r., m.v. sriramachandrasekharan and r. nagendran. 2011. effect of vermicompost on growth and yield of sunflower. plant arch. 11(1): 235-237. effect of organic and inorganic fertilizer for maximizing yield and oil content of sunflower 39 khan, r.m., s. mitra, m.t. hosain, m.m. rohman and m.h.n. miah. 2020. impact of nitrogen fertilizer on the growth, seed yield and quality of sunflower. bangladesh agron. j. 23(2): 85-94. lawal, b., g. obigbesan, w. akanbi and g. kolawole. 2011. effect of planting time on sunflower (helianthus annuus l.) productivity in ibadan, nigeria. african j. agric. res. 6: 3049-3054. mirshekari, b., m.j. zarea, m. shakarami, a.h. mohammadi and s. golbabayee. 2022. effect of different levels of nitrogen and phosphorus fertilizers on sunflower seed yield, oil content and oil productivity. agric. sci. digest-a res. j. 42(2): 123-128. supriya, s.m., v.v. kulkarni, c.n. ranganatha and p.g. suresha. 2009. quantitative analysis of oil yield and its components in sunflower (helianthus annuus l.). int. j. curr. microbiol. app. sci. 6: 3088–98. umar, h.s., m. okhovat and s.m. hosseini. 2017. effect of vermicompost and inorganic fertilizer on yield and nutrient uptake of sunflower. biosci. j. 33: 67-78. verma, s., d. singh, a. singh and v. prakash. 2017. integrated nutrient management in sunflower (helianthus annuus l.) under semi-arid tropics of india. j. environ. biol. 38(6): 1361-1365. zheljazkov, v.d., b.a. vick, m.w. ebelhar, n. buehring, b.s. baldwin, t. astatkie and j.f. miller. 2008. yield, oil content, and composition of sunflower grown at multiple locations in mississippi. agron. j. 100: 635–42. bangladesh agron. j. 2024, 27(1): 23-28 effect of plant population and integrated nutrient management on yield of yard long bean (vigna unguiculata) s.s. kakon1*, s. paul2, a.a. begum1, j.a. chowdhury1 and s.t. zannat1 1agronomy division, bangladesh agricultural research institute, gazipur 1701, bangladesh 2agronomy division, rars, jashore, bangladesh agricultural research institute, gazipur 1701, bangladesh *corresponding author, email: kakonbari@gmail.com (received: 20 january 2025, accepted: 21 july 2025) keywords: integrated nutrient management, tdm, yield, yard long bean, bcr abstract the experiment was conducted at agronomy research field of bari, gazipur during kharif1 seasons of 2020-21 and 2021-22 to evaluate the effect of manures and fertilizers and optimum plant population for higher yield of yard long bean. two planting geometry, viz., p1= 45 cm × 30 cm (8 plants m−2) p2= 40 cm × 20 cm (12.5 plants m−2) and three nutrient levels viz., f1=recommended fertilizer dose (rfd) (21-27-33-9-1.2-1.2 kg ha−1 npksznb), f2= ipns (16-25-30-9-1.2-1.2 kg ha−1 npksznb) + poultry manure (pm) (3 t ha−1) and f3 = ipns (16-25-30-9-1.2-1.2 kg ha−1 npkszn) + vermicompost (vc) (3 t ha−1) were used. the integrated treatment combinations involve both organic and inorganic source of nutrients which significantly influenced the growth and yield attributes. the better results in terms of vegetable fresh yield were obtained in the following order: pm > vc> npk. application of vc is not beneficial due to 15 times higher price than pm. the result indicated that plant spacing of 40 cm  20 cm with pm added npk fertilizer combination (f2) gave the maximum pod yield (4.90 t ha−1 in 2020-21 and 4.83 t ha−1 in 2021-22) which was statistically similar to same spacing with vc added npk fertilizer combination (f3) but the highest benefit cost ratio (2.15) was recorded in plant spacing of 40 cm  20 cm with pm added npk fertilizer combination (f2). from the result it might be could be concluded that plant spacing of 40 cm × 20 cm (1,25,000 plants ha−1) with organic and inorganic source of nutrients {ipns (16-2530-9-1.2-1.2 kg ha−1 npkszn) with pm (3 t ha−1)} was found to achieve the maximum productivity of yard long bean cultivation at gazipur. introduction vigna unguiculata (l.) commonly known as yard long bean or pole type vegetable cowpea belongs to the family fabaceae and is one of the most popular and remunerative vegetable crop traditionally grown in bangladesh, cultivated mainly for tender pods that are consumed both fresh and cooked. it is a rich and inexpensive source of vegetable protein and its cultivation enriches soil fertility by fixing atmospheric nitrogen. fresh pods are used as a green vegetable. the pods are rich in calcium, phosphorus, sodium, and potassium and also fair amounts of vitamin a, thiamine and ascorbic acid are present (piluek, 1994). it has become an essential component of sustainable agriculture in marginal lands of the tropics because of its quick growth habit. but the yield of yard long bean is quite low. it is usually growing during february/march to may/june. optimum plant spacing and low inputs or improper application of fertilizers resulted low yield. nowadays, increasing cost of inorganic fertilizers and reduction in soil health with chemical fertilizers, it is essential to replace inorganic fertilizers through organic for sustainable agriculture. in bangladesh different plant spacing of yard long bean are used by the farmers in different locations. moreover, organic matter content in bangladesh soils is very low (<1.5%) and is being gradually depleted (ullah et al., 2008). neither the chemical fertilizer nor organic manure alone can help 24 kakon et al. achieve sustainable crop production. the integrated nutrient management is the best approach to restore/ maintain soil fertility and productivity on sustainable basis. organic manure improves soil structure through aggregation favourably influencing tillage properties, crusting, water infiltration, moisture retention, aeration and temperature. but in bangladesh, most soils have less than 1.5%, and some even less than 1% organic matter contents (fao, 2014). organic fertilizers have been shown to help preserve natural resources and reduce degradation of ecosystem (francis and daniel, 2004). in bangladesh, now a day, the organic fertilizers like cowdung and chicken manure are available due to increasing dairy and poultry farm. on the other hand, the price of vermicompost is very high (15 times higher) comparable to cowdung and chicken manure. farmers of bangladesh are mostly habituated with the use of macronutrients, especially n, p, k and s for crop production. use of manures is limited. in addition, there are some reports on combined effect of npks (25%) and vermicompost (75%) have given higher yield of tomato, cabbage, okra compared to recommended dose of full amount npks and control (islam et al., 2017; akhter et al., 2019). however, information on the use of poultry manure and vermicompost in combination with inorganic fertilizers for yard long bean is scanty in bangladesh. considering the above facts, the present study was therefore under taken to investigate the effects of organic manure and inorganic fertilizer alone or in combination and appropriate plant spacing for higher yield of yard long bean. materials and methods the experiment was conducted at the research field of agronomy division bari, gazipur during kharif seasons of 2020-21 and 2021-22. the soil of the gazipur research area belongs to chhihata series under aez-28. initial soil nutrient status is given in table 1. in gazipur soil ph was (6.10 in 2020 and 6.28 2021-22) which indicated the soil was slight acidic. organic matter percentage was low in both the years. over the years nitrogen percentage was very low. phosphorus level was low. potassium level was low. sulphur status was low in gazipur location. organic matter concentration, total n, available p, exchangeable k, available s and available b was higher in poultry manure and vermicompost. table 1. initial soil nutrient status of gazipur location during kharif season of 2020-21 and 2021-22 location ph om (%) total n (%) exchangeable k (meq 100−1g soil) available p (µg ml−1) available s (µg ml−1) available zn (µg ml−1) available b (µg ml−1) agronomy field bari, gazipur 2020-21 6.10 1.41 0.148 0.095 5.65 11.38 0.24 0.160 2021-22 6.28 1.41 0.11 0.161 14.31 12.37 0.24 0.160 vl l l l l vl l poultry manure 8.1 18.7 2.13 2.55 0.87 0.90 0.11 vermicompost 7.2 25.3 1.24 2.0 1.06 0.87 0.015 note: h=high, m= medium, l= low, vl= very low the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 3.6 m × 3.0 m. two planting spacing, viz., p1= 45 cm × 30 cm (8 plants m−2), p2= 40 cm × 20cm (12 plants m−2) and three fertility levels viz., f1 = recommended fertilizer dose rfd) (21-27-33-9-1.2-1.2 kg ha−1 npksznb), f2= ipns + poultry manure (3 t ha−1) and f3 =ipns + vermicompost (3 t ha−1) were used. seeds of yard long bean were sown on 1 march, 2021 and 18 march, 2022. fertilizers were applied as per treatments in the form of urea, tsp, mop, gypsum, zinc sulphate and boric acid. one-third of urea and full amount of all other fertilizers were applied at the time of final land preparation. the remaining urea was top dressed in two equal splits at 35 and 50 das (days after sowing). a light irrigation was given after sowing of seeds uniform for germination. three irrigations effect of plant population and integrated nutrient management on yield of bean 25 were done at 25 and 50 das. intercultural operations like thinning were done at 15 das and weeding was done two times at 15 and 25 das. for dry matter estimation, 5 plants were sampled at maturity. yard long bean was harvested several times started on 13 may, 2021 and 17 may, 2022. for dry matter at harvest, 10 plants were randomly collected from each plot and oven dried at 80oc for 72. the yield component data was taken from 5 randomly selected plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise. the collected data were analyzed statistically using mstat-c package and means were adjudged by least significant difference (lsd) test at 5% level of probability. cost and return performance of the study was also evaluated. results and discussion total dry matter production total dry matter (tdm) production of yard long bean was influenced by spacing and inorganic and organic fertilizer combination in both the years. total dry matter reduced in plant spacing p1 [45cm × 30cm (8 plants m−2)] under all fertilizer treatments. it might be due to lower population (8 plants m−2) and leaf senescence caused by might reduce the photosynthetic efficiency and ultimately reduced the dry matter accumulation. total dry matter was higher (218 g m−2 and 224 g m−2) in p2f2 followed by p2f3 treatment. the lowest tdm was observed from p1f1 and p1f3 treatments (fig.1a and fig.1b). vc and poultry matter (pm) treatments had a beneficial optimistic effect on tdm production of yard long bean. similar results were reported by mohanty et al. (2017) in french bean. fig. 1. total dry matter (tdm) production of yard long bean at harvest as influenced by planting geometry and fertilizer levels during 2020-21 (a) and 2021-22 (b). here, two spacing: p1=40 cm  25 cm, p2 = 40 cm  20 cm and three fertilizer dose: f1= rfd (21-27-33-9-1.2-1.2 kg ha−1 npksznb), f2 = ipns + poultry manure (3 t ha−1), f3 =ipns + vermicompost (3 t ha−1) plant population, plant height, yield attributes and yield number of plants m−2, plant height at harvest, number of pods plant−1 of yard long bean showed significant variations due to planting geometry and inorganic and organic fertilizer combination in both the years (table 2). number of plants m−2 at harvest varied widely, which ranged between 6 and 11. plant height at maturity varied from 52.53 to 61.48 cm regardless 0 50 100 150 200 250 p1f1 p1f2 p1f3 p2f1 p2f2 p2f3 t o ta l d ry m a tt e r (g m − 2 ) treatment a 0 50 100 150 200 250 p1f1 p1f2 p1f3 p2f1 p2f2 p2f3 t o ta l d ry m a tt e r (g m − 2 ) treatment b 26 kakon et al. of treatments. the maximum plant height over the years (57.73 cm and 61.48 cm) was recorded from planting density p2f3 (which was followed by p2f2.the shortest plant over the years (52.53 cm and 53.51 cm) was in p1f1 treatment. the increase in height of yard long bean plants amended with organic is probably due to release of nutrients which promoted vigorous plant growth through efficient photosynthesis (mondal et al., 2019). nitrogen fertilization had a tendency to increase plant height as nitrogen involves in cell division and cell elongation of plants (mazumder et al., 2019). the number of pods per plant increased with decrease in plant density. the number of pods plant−1 ranged between 9 and 17 across the fertility level and plant population. the decrease in the number of pods per plant with the increase in plant density could be due to increased intra row competition which eventually might have caused reduction in the number of pods plant−1 as a result of higher net assimilation rate and reduction of competition in wider spacing and also nutrient, moisture and light. the maximum number pods plant−1 over the years (15 and 17) was recorded with 8 plant m−2 when the crop was fertilized with ipns + 3 t ha−1 pm which was statistically similar to ipns + 3 t ha−1 vc. these results are in conformity with the findings of sharma et al. (2008), jakusko et al. (2009), bakry et al. (2011), almaz et al. (2016). higher pod length (28.50 cm in 2020-21 and 28.77cm in 2021-22) was obtained from p1f2 treatment followed by p1f3. the lowest pod length over the years (24.77 cm and 20.63 cm) was recorded in p2f1 treatment. pod yield of yard long bean was also found significantly differed due to spacing and inorganic and organic fertilizer combination (table 2). the maximum pod yield (4.90 t ha−1 and 4.83 t ha−1) was recorded from p2f2 (planting density 12 m−2 under ipns + 3 t ha−1 pm) treatment which was statistically similar with p2f3 treatment. all the yield contributing characters were higher in p1 plant spacing but pod yield was higher in p2 due to higher plant population. therefore, the combined application of manures and fertilizers could supply the nutrients timely and also maintain the suitable condition for flowering, fruiting and their growth. the findings of this investigation confirm the results of earlier work singh and chauhan (2009) who reported that, organic and inorganic fertilizers combinations significantly increase the growth and pod yield attributes in french bean. these results are in conformity with the findings of sharma et al. (2008), jakusko et al. (2009), bakry et al. (2011), almaz et al. (2016). the lowest pod yield over the years (3.64 t ha−1 and 3.67 t ha−1) was obtained from p1f1 treatment. it might be due to lower number of plant population ha−1 (100000 plants ha−1). addition of pm or vc greatly improved the yield of yard long bean in this study compared to npk fertilizers and this confirms the findings of xu et al. (2005) who stated that higher total yield than those grown with organic fertilizers. table 2. plant population, plant height at harvest, yield attributes and yield of yard long bean as influenced by planting geometry and integrated nutrient management interaction (spacing × fertility level) population m−2 (no.) plant height (cm) pod plant−1 (no.) pod length (cm) pod yield (t ha−1) 2020-22 202021 202122 202021 202122 202021 202122 202021 202122 p1 × f1 6 52.53 53.51 12 15 26.83 25.31 3.64 3.67 p1 × f2 7 54.83 55.50 15 17 28.50 28.77 3.84 4.02 p1 × f3 7 51.60 54.37 14 16 25.97 27.10 3.80 4.09 p2× f1 11 55.47 55.80 9 9 24.77 20.63 4.35 4.38 p2 × f2 10 56.07 60.01 11 13 27.13 22.00 4.90 4.83 p2 × f3 9 57.73 61.48 12 13 26.47 24.04 4.84 4.87 lsd (0.05) 1.31 1.41 1.50 1.01 0.96 1.05 0.96 0.13 0.05 cv (%) 8.23 3.30 3.15 4.68 3.86 4.17 4.17 3.03 4.15 two spacing: p1=40 cm 25 cm, p2=40 cm  20 cm and three fertilizer dose: f1= rfd (21-27-33-9-1.2-1.2 kg ha−1 npksznb), f2= ipns+ poultry manure (3 t ha−1), f3 =ipns + vermicompost (3 t ha−1), npk = nitrogen, phosphorus, potassium; pm = poultry manure, vc=vermicompost effect of plant population and integrated nutrient management on yield of bean 27 cost and return application of manures with npk had positive effect on economic return over control (table 3). in general, pm added plots had higher benefit than vc added plots. from the costbenefit analysis it was found that the highest gross return (tk. 1,45,876 ha−1) was obtained from p2f2 treatment and the lowest gross return (tk.91,073 ha−1) was found in p1f1 treatment. the highest cost of cultivation was recorded in p2f3 treatment (tk. 91,364 ha−1) due to higher labour and fertilizer cost. the highest gross margin (tk. 77,946 ha−1) was obtained from p2f2 treatment. the highest benefit cost ratio (2.15) was obtained from p2f2 treatment and the lowest bcr (1.29) was recorded in p1f3 treatment (table 3). though p2f3 treatment produced the highest pod yield but this treatment showed the lowest bcr (1.29) due to higher labour and fertilizer cost. the results were consistent with the earlier reports of lower labour and fertilizer cost which gave the highest fruit yield and returns (islam et al., 2012 and subrahmaniyan et al., 2011). table 3. cost and return of yard long bean as influenced by planting geometry and integrated nutrient management (pooled of 2020-21 and 2021-22) treatment gross return (tk ha−1) cost of production (tk ha−1) gross margin (tk ha−1) benefit cost ratio p1 × f1 91364 58850 32514 1.55 p1 × f2 117912 62970 54942 1.87 p1 × f3 118374 91430 26944 1.29 p2× f1 109167 63885 45282 1.71 p2 × f2 145876 67930 77946 2.15 p2 × f3 145669 97630 48039 1.49 two spacing: p1 = 40 cm 25 cm, p2 = 40 cm  20 cm and three fertilizer dose: f1 = rfd (21-27-33-9-1.2-1.2 kg ha−1 npksznb), f2 = ipns+ poultry manure (3 t ha−1), f3 = ipns + vermicompost (3 t ha−1); npk = nitrogen, phosphorus, potassium; pm = poultry manure, vc=vermicompost. the price rate of manures and fertilizers (taka): urea: tk. 16.00 kg−1, tsp: tk. 11.00 kg−1, mop: tk. 15.00 kg−1, pm: tk. 1.00 kg−1 and vc: tk. 15 kg−1. the fresh yard long bean rate was tk. 25.00 kg−1 conclusion from the result it could be concluded that plant density of 40 cm × 20 cm (1,25,000 plants ha−1) with integrated nutrient management practices {organic poultry manure (3 t ha−1) and inorganic combination)} was found to achieve the maximum productivity of yardlong bean which in turn gives high returns to the farmers. reference akhter, a., m.a. islam and m.r. karim, 2019. effects of nutrient management and netting on the growth and yield of okra. fundam. appl. agric. 4(1): 627-631. almaz, m., t. gezahegn, j.j. sharma and m.d. belel. 2016. determination of optimum plant density for faba bean (vicia faba l.) on vertisols at haramaya, eastern ethiopia. cogent food agric. 2:122128. bakry, b.a., t.a. elewa, m.f. el-karamany, m.s. zeidan and m.m. tawfik. 2011. effect of row spacing on yield and its components of some faba bean varieties under newly reclaimed sandy soil condition. world j. agric. sci.7(1): 68-72. fao, 2014. food and agriculture organization. production year book of 2014. farjana, s., m.a. islam and t. haque. 2019. effects of organic and inorganic fertilizers and mulching on growth and yield of cabbage (brassica oleracea var. capitata l.). j. hort. postharvest res. 2(2): 110. francis, c.a. and h. daniel. 2004. organic farming encyclopedia of soils in the environment. elsevier, oxford, uk. pp. 77-84. 28 kakon et al. islam, m.r., m.a.k. mian and m.t. rahman. 2012. suitability of intercropping sesame with mukhikachu. bangladesh j. agric. res. 37(4): 625-634. islam, m.a., s. islam, a. akter, m. rahman and d. nandwani. 2017. effect of organic and inorganic fertilizers on soil properties and the growth, yield and quality of tomato in mymensingh, bangladesh. agric.7:18 jakusko, b.b., u.i. anasunda, and a.b. mustapha. 2013. effect of inter-row spacing on some selected cowpea (vigna unguiculata (l) walp) varieties in yola, adamawa state, nigeria. iosr j. agric. vet. sci.2, no. 3 (2013): 30-35. mader, p., a. fliessbach, d. dubois, p. fried and u. niggli, 2002. soil fertility and biodiversity in organic farming, sci. 296:1694-1697. mondal, m.m.a., farid a., k.m.e. nabi, m.m.a. noor and m.t.r. mondal. 2019. performance of organic manures on the growth and yield of red amaranth (amaranthus tricolor) and soil properties. res. agric., livest. fish. 6(2): 263-269. mazumder, n., t. sultana, p. paul and m.m. noor. 2019. influence of npk fertilizer and spacing on growth parameters of onion (allium cepa l. var. bari piaz-1). res. agric., livest. fish. 6(1): 1925 mohanty s., g.s. sahu, s.k. dash, s.r. pradhan, s.mangaraj and s. nahak. 2017. integrated nutrient management for seed production in french bean phaseolus vulgaris (l.). int. j. curr. microbiol. appl. sci. 6(10): 3295-3303. piluek, k. 1994. the importance of yardlong bean. in: proc. 2nd symp. vegetable legumes. kasetsart university research and development institute and arc-avrdc, bangkok, thailand. sharma, v.k., p. pathania and g.d. sharma. 2008. response of french bean (phaseolus vulgaris l.) varieties to sowing dates and plant density in cold desert region. legume res. 31(3): 230-231. singh n.i. and j.s. chauhan. 2009. response of french bean (phaseolus vulgaris l.) to organic manures and inorganic fertilizer on growth & yield parameters under irrigated condition. nat. sci. 7(5):1-3. subrahmaniyan, k., w. zhou, and p. veeramani. 2011. weed control through degradable, herbicidal and organic plastics and organic mulches and their effect on crop growth and yield of winter rapeseed (brassica napus). indian j. of agri. sci. 81(4): 348-352. ullah, m.s., m.s. islam, m.a. islam and t. haque. 2008. effects of organic manures and chemical fertilizers on the yield of brinjal and soil properties. j. bangladesh agril. univ. 6(2): 271–276. xu, h.l., r. wang, r.y. xu, m.a. mridha and s. goyal. 2005. yield and quality of leafy vegetables grown with organic fertilizations, acta hortic. 627: 25-33. bangladesh agron. j. 2022, 25(2): 97-107 yield of mungbean as influenced by planting geometry and integrated fertilizer management m.s. hosen, s.c. sarker1, h.m.m.t. hossain1, m. roy2, m. hasanuzzaman1, a. rahman1 1department of agronomy, sher-e-bangla agricultural university, dhaka 1207. 2department of agricultural forestry and environmental science, sher-e-bangla agricultural university, dhaka *corresponding e-mail: shimulsau@gmail.com (received: 24 november 2022, accepted: 16 december 2022) keywords: planting geometry, yield, organic and inorganic fertilizers abstract mungbean production is decreasing because of inappropriate management of fertilizer and plant population so a study was initiated to find out the effect of different combinations of organic and inorganic fertilizers with different plant geometry on the yield of mungbean var. bari mung-5. the experiment was laid out in a splitplot design with three replications. the experiment comprised of three level of plant geometry viz. s1= 20 cm × 10 cm, s2= 30 cm × 10 cm and s3= 45 cm × 15 cm, and six level of fertilizers: f0= control (without fertilizer), f1= recommended dose of npk, f2=5 t ha-1cowdung, f3=5 t ha-1cowdung with recommended dose of npk, f4= 2.5 t ha-1 cowdung with recommended dose of npk and f5=2.5 t ha-1cowdung with half recommended dose of npk. among the three spacing, 30 cm × 10 cm (s2) produced maximum seed yield (1022.8 kg ha-1) while the lowest in s3 (834.4 kg ha-1). cowdung had a significant effect on the seed yield and yield attributes of mungbean. the maximum seed yield (1038.9 kg ha-1) was obtained f4 while minimum (930.0 kg h-1) by applying cowdung @5 t ha-1. among the treatment combinations, s2f4 was showed maximum yield (1156.7 kg ha-1) when considering stover yield and biological yield. plant spacing of 30 cm × 10 cm along with 2.5 t ha-1 with recommended dose of 40, 80, 30 kg ha-1 of urea, tsp, mop could be more beneficial for the farmers to get maximum yield from var. bari mung-5. introduction mungbean (vigna radiata) is the most important pulse crop of bangladesh and positions the third in protein substance and ranked fourth in respect of pulse cropped area (moa, 2014). according to fao (2013), a minimum intake of pulse by an individual should be 80 g/day, whereas it is 47.92 g in bangladesh (bbs, 2016). in bangladesh, total yield of pulses is only 0.65 million ton (mt) against 2.7 mt requirement. this implies the lack is practically 80% of the complete prerequisite (rahman and ali, 2007). presumably, the lower yield of mungbean is one of the main reasons behind this disparity (moa, 2005). a good quality soil should have at least 2.5% organic matter, but in bangladesh most of the soils have less than 1.5%, and some soils even less than 1% organic matter (barc, 2005). crop residues and soil organic matter both could influence the diversity of soil microbial community and promote the crop growth and yield. integrated management of chemical fertilizers and organic wastes may be an important approach for sustainable production of crops. 98 hosen et al. organic farming express as large-scale use of animal or farm yard manure (fym), compost, crop residues, green manuring, vermicompost, bio-fertilizers and bio-pesticides. but it may not be possible to obtain desired production from sole use of organic fertilizers. equilibrium use of fertilizer is important to obtain maximum seed yield. being leguminous in nature, mungbean needs low nitrogen but optimum doses of other major nutrients as per recommendation. besides, optimum planting density is an important aspect of modern agriculture for securing good yield (ahamed et al., 2011). absorption of efficient sunlight depends on the equal distribution of leaf area, this is possible by proper row spacing and distributing plants in the field (naseri et al., 2010). high planting density increases competition among the plants and reduce the absorption of light, water and nutrient. the plant having wider spacing produce extra branch and pod, but the number of pods per unit area become low as a result it decreases the yield (singh et al., 2003).therefore, optimum plant population ensures normal plant growth due to efficient utilization of moisture, light, space and nutrients, thus increases the yield of crop. considering the above facts, the study has been undertaken to find out the influence of plant spacing and combinations of fertilizers on the yield performance of mungbean variety. materials and methods the experiment was conducted at the agronomy field at sher-e-bangla agricultural university, dhaka during the period from march to may, 2022. the mungbean var. bari mung-5 of used for the study. the experiment comprised of three levels of plant spacing viz. s1= 20 cm × 10 cm, s2= 30 cm × 10 cm (bari recommended) and s3= 45 cm × 15 cm, and six level of fertilizers: f0= control (without fertilizer), f1= recommended dose of nitrogen(n), phosphorus (p) and potassium (k) f2=5 t ha-1cowdung, f3=5 t ha-1 cowdung with recommended dose of npk, f4= 2.5 t ha-1 cowdung with recommended dose of npk and f5= 2.5 t ha-1cowdung with half recommended dose of npk. the experiment was laid out in split-plot design having three replications. spacing placed in the main plot whereas fertilizer in the sub -plots. the plot size was 10 m2. the recommended dose of chemical fertilizers were applied as 40, 80, 30 kg ha-1 of urea, tsp, mop. all the fertilizers and cowdung were applied as per treatment combination by broadcasting and mixed with soil thoroughly at the time of final land preparation. different intercultural operations (thinning, weeding, irrigation, drainage and plant protection measures etc.) were taken at different days after sowing. the insecticide sumithion 57 ec was sprayed at the rate of 0.02% at the period of pod formation to control pod borer. no disease was observed in the experimental field. data on pod length, pods per branch, pods per plant, seeds per pod, 1000-seed weight, seed yield were collected for different treatments. data recorded for yield parameters and analysis of variance was done following computer package mstat-c programme. mean differences among the treatments were tested with least significant differences (lsd) at 5% level. results and discussion yield contributing characters pod length different plant spacing and fertilizer dose showed significant effect on pod length (cm). the maximum pod length (7.81 cm) was observed from 30 cm × 10 cm (s2) treatment which was statistically similar (7.7 cm) with s3 treatment (fig.1a). in case of fertilizer dose, maximum pod length (7.93 cm) was observed from f4 treatment, which was statistically similar to f5 (7.81 cm) and f3 (7.75 cm) treatment whereas minimum pod length (7.16 cm) from f0 treatment (fig. 1b). in case of interaction effect the maximum pod length (8.06 cm) was observed from s3f4 effect of planting geometry and integrated fertilizer management on mungbean yield 99 treatment combination which was statistically similar to s2f4, s2f5, s2f3, s3f2, s3f3, s3f5, s1f5, s2f1 s2f2 and s1f4 treatment combination (table 1). the minimum pod length (6.78 cm) was observed from s1f0 treatment combination which was statistically similar (7.1 cm) s3f0 treatment combination. previous findings shows that the low planting density per unit area i.e. higher plant spacing helps the plant to uptake extra nutrient and water. they also get more sunlight which was helpful for photosynthesis, consequently more dry matter partitioning to the reproductive unit of plant (pod), thus amplified the pod length compared to the densely populated plot (agasimani et al., 1984). nitrogen might increase the branch number plant-1 of mungbean as a result the pod length increased and it was in full agreement with hossen et al. (2015). s1 = 20 cm × 10 cm, s2 = 30 cm × 10 cm, s3 = 45cm × 15cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1 cowdung with recommended dose of npk, f4= 2.5 t ha-1 cowdung with recommended dose of npk, f5= 2.5 t ha-1cowdungwith half of recommended dose of npk. (lsd (0.05) = 0.24 for plant spacing and 0.23 for fertilizer dose) fig.1. effect of spacing and fertilizer on pod length of mungbean pods per branch number of pods branch plant-1 was influenced by different plant spacing and nutrient management. the maximum pods branch plant-1 (5.6) was observed from s3 treatment where as minimum pods branch plant-1 (3.69) from s2 treatment (fig.2a). the maximum pods branch-1 (6.13) was observed from f4 treatment whereas minimum (3.17) from f0 (fig.2b). s1 = 20cm × 10 cm, s2 = 30cm × 10 cm, s3 = 45cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung with recommended dose of npk, f4= 2.5 t ha-1cowdung with recommended dose of npk, f5 = 2.5 t ha-1cowdung with half of recommended dose of npk. lsd (0.05) = 0.13 for plant spacing and 0.12 for fertilizer dose, respectively fig. 2. effect of spacing and fertilizer dose on number of pods per branchof mungbean 0 1 2 3 4 5 6 7 s1 s2 s3 p o d b ra n c h -1 plant spacing a 0 2 4 6 8 10 s1 s2 s3 p o d le n g th ( c m ) plant spacing a 0 2 4 6 8 10 f0 f1 f2 f3 f4 f5 p o d l e n g th ( c m ) fertilizer dose b 0 1 2 3 4 5 6 f0 f1 f2 f3 f4 f5 p o d b ra n c h -1 fertilizer dose b 100 hosen et al. in case of treatment combinations, the maximum pods branch plant-1 (7.17) was observed from 45cm × 15 cm spacing along with 2.5 t ha-1cowdung with recommended dose of npk(s3f4), whereas minimum pods branch plant-1 (2.46) from s2f0 treatment combination which was statistically similar (2.50, 2.5 and 2.64) with s2f0, s1f0and s2f5 treatment combinations, respectively. number of pods per branch might be varied due to plant spacing. hossen et al. (2015) found that significant variation on number of pods per branch among mungbean plant. aslam et al. (2010) also found that combined application of fym, poultry manure and chemical fertilizer recorded higher number of pods branch-1 that indicating earlier of integration of the two sources in having improved mungbean productivity. pods plant-1 different plant spacing showed significant effect on number of pods plant-1 (fig.3a). the maximum number of pods plant-1 (21.11) was observed from s3 treatment, which was statistically similar to 30 cm × 10 cm (s2) pods plant-1 of 20.57. the minimum number of pods plant-1(18.33) was observed from s1 treatment. it was also found that the maximum number of pods plant-1 (22.18) was observed from f4 treatment whereas minimum number of pods plant-1 (18.7) was observed from f0 treatment, which was statistically similar (18.74) to f2 treatment (fig. 3b).interaction effect of different plant spacing and combination of organic and inorganic fertilizers showed significant variation on number of pods plant-1. the experimental result showed that the maximum number of pods plant-1 (24.44) was observed from 45cm × 15 cm spacing along with 2.5 t ha-1 cowdung with recommended dose of npk(s3f4) treatment combination (table 1). while minimum number of pods plant-1 (17.11) was observed from s1f0 treatment combination which was statistically similar (17.55) with s3f2treatment combination (table 1). it seems that plants grown at wider spacing met with lower intra-specific competition throughout the growing period which produces higher number of pod. hossen et al. (2015) also found that plant density effects on pod number while asaduzzaman et al. (2008) and srinivas et al. (2002) also observed that the organic manure boost up the available form of chemical nutrients and plant easily uptake of soil nutrients which influence the number of pod. s1 = 20 cm × 10 cm, s2 = 30 cm × 10 cm, s3 = 45 cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1 cowdung with recommended dose of npk, f4= 2.5 t ha-1cowdung with recommended dose of npk, f5 = 2.5 t ha-1 cowdung with half of recommended dose of npk lsd (0.05) = 0.69 for plant spacing and 0.64 fertilizer dose, respectively. fig. 3. effect of spacing and fertilizer dose on pods plant-1 of mungbean 0 5 10 15 20 25 s1 s2 s3 p o d p la n t1 plant spacing a 0 5 10 15 20 25 f0 f1 f2 f3 f4 f5 p o d p la n t1 ferlitizer dose b effect of planting geometry and integrated fertilizer management on mungbean yield 101 seeds pod-1 various plant spacing showed significant effect on number of seeds pod-1 (fig. 4a). the experimental result exhibited that the maximum number of seeds pod-1 (11.62) was observed from s3 treatment, which was statistically similar (11.59) to s2 treatment and the maximum number of seeds pod-1 (12.04) from f4 treatment whereas minimum seeds pod-1 (10.56) from f0 treatment (fig. 4b). it also observed that the maximum seeds pod-1 (12.90) was observed from s3f4 treatment combination whereas minimum number of seeds pod-1 (9.67) from s1f0 treatment combination. foysal et al. (2016) and rasul et al. (2012) found that planting density significantly influenced the number of seeds pod-1. they also found that lower planting density gave the higher number of seeds pod-1. nigamananda and elamathi (2007) explained that organic and inorganic fertilizer mixtures showed significant effect on seeds pod-1. s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45 cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk . lsd (0.05) = 0.50 for plant spacing and 0.48 for fertilizer dose respectively. fig. 4. effect of spacing and fertilizer dose on number of seed per plant of mungbean 1000-seed weight the experimental result exhibited that the maximum 1000-seed weight (48.72 g) was observed from s3 treatment, which was statistically similar (48.36 g) to s2 treatment (fig. 5a). the maximum 1000-seed weight (50.84 g) was observed from 2.5 t ha-1cowdung + recommended npk (f4) treatment. whereas minimum thousand seeds weight (45.83) was observed from f0 treatment (fig. 5b). the experimental result showed that the maximum thousand seeds weight (51.47 g) was observed from s3f4 treatment combination, which was statistically similar (51.43, 49.61, 49.61, 49.52 and 49.33 g) to the treatment combinations of s2f4, s1f4, s3f1, s3f2, s3f1 and s2f2. the minimum thousand seeds weight (45.247 g) was observed from s2f0 treatment combination, which was statistically similar (45.74, 45.83, 46.51, 47.14, 47.34 and 47.37 g) to s1f0, s1f3, s3f0, s1f1, s3f3 and s1f2 treatment combinations (table 1). it was also found that plant spacing significantly affected the seed yield of legumes (porwal et al., 1991). rasul et al. (2012) explained that wider row spacing help to get highest 1000-seed weight of mungbean. it was also observed that combination of organic and inorganic fertilizers showed significant effect on thousand seeds weight (razzaque et al., 2015 and hossen et al., 2015). 0 2 4 6 8 10 12 s1 s2 s3 s e e d s p o d -1 plant spacing a 0 2 4 6 8 10 12 f0 f1 f2 f3 f4 f5 s e e d s p o d -1 fertilizer dose b 102 hosen et al. s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk lsd (0.05) =1.23 for plant spacing and 1.19 for fertilizer dose, respectively. fig. 5. effect of spacing and fertilizer dose on thousand seeds weight of mungbean table 1. interaction effect of spacing and fertilizer dose on yield contributing characters of mungbean treatment yield contributes characters combinations pod length (cm) pods branch-1 (no.) pods plant-1 (no.) seeds pod-1 (no.) 1000 -seed weight (g) s1f0 6.78d 2.5j 17.11i 9.67d 45.74fg s1f1 7.51bc 4.5f 18.33gh 11.5bc 47.14d-g s1f2 7.52bc 2.92i 18.33gh 11c 47.37c-g s1f3 7.6b 5.19de 18.33gh 11c 45.83fg s1f4 7.68ab 5.26d 19.33efg 11.33bc 49.61ab s1f5 7.78ab 5.33d 18.56fgh 11.27bc 47.59b-f s2f0 7.59b 2.46j 18.78fg 11c 45.25g s2f1 7.77ab 3.82g 21.44cd 11.6bc 48.19b-e s2f2 7.74ab 3.3h 20.33de 11.8bc 49.33a-d s2f3 7.86ab 3.95g 21.44cd 11.8bc 48.2b-e s2f4 8.06a 5.96c 22.78b 11.9b 51.43a s2f5 7.86ab 2.64ij 18.67fgh 11.47bc 47.76b-f s3f0 7.1cd 4.55f 20.22e 11c 46.51e-g s3f1 7.62b 5.29d 22.44bc 11.13bc 49.52a-c s3f2 7.84ab 5.09de 17.55hi 11.67bc 49.61ab s3f3 7.79ab 6.51b 19.55ef 11.5bc 47.34d-g s3f4 8.06a 7.17a 24.44a 12.9a 51.47a s3f5 7.78ab 4.97e 22.44bc 11.5bc 47.88b-f lsd(0.05) 0.40 0.23 1.11 0.83 2.07 cv (%) 3.14 3.04 3.33 4.37 2.58 note: s1: 20cm × 10 cm, s2:30cm × 10 cm, s3: 45cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk yield parameters seed yield the experimental result exhibited that the maximum seed yield (1022.8 kg ha-1) was observed from s2 treatment whereas minimum seed yield (834.4 kg ha-1) from s3 treatment (fig. 6a). in 40 42 44 46 48 50 52 s1 s2 s3 1 0 0 0 s e e d s w e ig h t (g ) plant spacing a 40 42 44 46 48 50 52 f0 f1 f2 f3 f4 f5 1 0 0 0 s e e d s w e ig h t (g ) fertilizer dose b effect of planting geometry and integrated fertilizer management on mungbean yield 103 case of fertilizer management, the maximum seed yield (1038.9 kg ha-1) was observed from f4 treatment. the minimum seed yield (772.2 kg ha-1) was observed from f0 treatment (fig.6b). the maximum seed yield (1156.7 kg ha-1) was observed from s2f4 treatment combination on the other hand minimum seed yield (693.3 kg ha-1) was observed from s3f0 treatment combination (table 2). plant produced low seed yield in close spacing because there was huge intra plant competition between them for moisture, sunlight and soil nutrients. this result was also coincide with rasul et al., (2012); ali et al. (2010); panwar and sirohi (1987) and agarico (1985), who reported that, crop sown at inter-row spacing of 30 cm gave maximum seed yield while lowest seed yield at inter-row spacing of 60 cm. consistent with organic and inorganic fertilizers mixtures effect on pods per plant, the effect was also significant on seed yield (haque et al., 2001, asaduzzaman et al., 2008 and kamal et al., 2001). s1: 20 cm × 10 cm, s2: 30 cm × 10 cm (recommended), s3: 45 cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1 cowdung, f3 = 5 t ha-1 cowdung + recommended npk, f4= 2.5 t ha-1 cowdung + recommended npk, f5= 2.5 t ha-1 cowdung + 1/2 recommended npk lsd (0.05) = 29.59 for spacing and 27.699 for fertilizer dose, respectively. fig. 6. effect of spacing and fertilizer dose on grain yield of mungbean stover yield stover yield of mungbean was significantly differed due to the application of different spacing. from the experiment result exhibited that the maximum stover yield (1974.2 kg ha-1) was observed from s1 treatment. whereas minimum stover yield (1421.7 kg ha-1) was observed from s3 treatment (fig. 7a); s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45 cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk. lsd (0.05)= 53.43 for spacing and 50.74 for fertilizer dose, respectively. fig. 7. effect of spacing and fertilizer dose on stover yield of mungbean 0 200 400 600 800 1000 1200 s1 s2 s3 g ra in y ie ld ( k g h a -1 ) plant spacing a 0 200 400 600 800 1000 1200 f0 f1 f2 f3 f4 f5 g ra in y ie ld ( k g h a -1 ) fertilizer dose b 0 500 1000 1500 2000 2500 s1 s2 s3 s to v e r y ie ld ( k g h a -1 ) plant spacing a 0 500 1000 1500 2000 2500 f0 f1 f2 f3 f4 f5 s to v e r y ie ld ( k g h a -1 ) fertilizer dose b 104 hosen et al. f2 treatment gave the maximum stover yield (1850 kg ha-1) whereas f4 treatment gave the minimum (1606.3 kg ha-1), which was statistically similar (1647.8) to f0 treatment(fig.7b).in different treatment combinations the maximum stover yield (2180 kg ha-1) was observed from s1f2 treatment and minimum (1258.7 kg ha-1) was from s3f0 treatment which was statistically similar (1280 kg ha-1) to s3f1 treatment(table2).these results uphold with the findings of foysal et al. (2016); kabir and sarkar (2008) and hossen et al. (2015) concluded that stover yield differed significantly among the spacing and fertilizers combinations. biological yield the experimental result showed that the maximum biological yield (2878.1 kg ha-1) was observed from s1 treatment whereas minimum biological yield (2256.2 kg ha-1) from s3 treatment (fig.8a). the maximum biological yield (2780 kg ha-1) was observed from f2 treatment which was statistically similar (2683.2 kg ha-1) with f5 treatment where the minimum biological yield (2420 kg ha-1) from f0 treatment(fig.8b). in case of the application of different spacing and fertilizer management the maximum biological yield (3076.7 kg ha-1) was observed from s1f2 treatment combination which was statistically similar (3006.7, 2973.3, 2930, 2873.7 kg ha-1) from s2f2, s2f1, s1f5 and s1f4 treatment combinations whereas minimum biological yield (1952 kg ha-1) from s3f0 treatment combination, which was statistically similar (2083.3 kg ha-1) to s3f1 treatment combination (table 2).the more biomass produced at low spacing because of maximum plant population (ghasempour and ashori, 2014 and khan et al. 2001).the use of cowdung increased the biological yield of legumes (mahboob and asghar, 2002). s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45cm × 15 cm, f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk lsd (0.05) = 140.53 for spacing and 132.32 for fertilizer dose, respectively fig. 8. effect of spacing and fertilizer dose on biological yield of mungbean harvest index harvest index of mungbean was significantly differed due to the application of different spacing and combination of organic and inorganic fertilizers. the maximum harvest index (37.14%) was observed from s2 treatment which was statistically similar (36.98%) with s3 treatment (fig. 9a). on the other hand the maximum harvest index (39.35%) was observed from f4 treatment, whereas minimum harvest index (32.28%) from f0 treatment (fig. 9a). the result of the investigation also revealed that the maximum harvest index (44.71%) was observed from s2f4 0 500 1000 1500 2000 2500 3000 f0 f1 f2 f3 f4 f5 b io lo g ic a l y ie ld ( k g h a -1 ) fertilizer dose b 0 500 1000 1500 2000 2500 3000 s1 s2 s3 b io lo g ic a l y ie ld ( k g h a -1 ) plant spacing a effect of planting geometry and integrated fertilizer management on mungbean yield 105 treatment combination while minimum (28.19%) was observed from s1f0 treatment combinations followed by (29.14, 29.97 and 31.06 %) with s1f2, s1f1 ands1f5 treatment combinations (table 2). row spacing (40 cm) helped to get highest harvest index of mungbean as also supported by mansoor et al. (2010) and khan et al. (2001). s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45 cm × 15 cm, f1 = bari recommended npk, f2 = 5 t ha-1 cowdung, f3 = 5 t ha-1 cowdung + recommended npk, f4= 2.5 t ha-1 cowdung + recommended npk, f5= 2.5 t ha-1 cowdung + 1/2 recommended npk lsd (0.05) = 2.07 for spacing and 1.93 for fertilizer dose, respectively fig. 9. effect of spacing and fertilizer dose on biological yield of mungbean table 2. interaction effect of spacing and fertilizer dose on yield characters of mungbean treatment yield character combinations seed yield (kg ha-1) stover yield (kg ha-1) biological yield (kg ha-1) harvest index (%) s1f0 770k 1961.3b 2731.3c-f 28.191h s1f1 850h-j 1986.7b 2836.7b-e 29.97gh s1f2 896.7f-h 2180a 3076.7a 29.14h s1f3 950de 1870cd 2820b-f 33.69d-f s1f4 1046.7bc 1827de 2873.7a-d 36.42b-e s1f5 910e-g 2020b 2930a-c 31.06f-h s2f0 853.3h-j 1723.3f 2576.7fg 33.12e-g s2f1 996.7cd 1976.7b 2973.3a-c 33.52d-g s2f2 1050b 1956.7bc 3006.7ab 34.92c-e s2f3 1050b 1596.7g 2646.7d-g 39.67b s2f4 1156.7a 1430.3i 2587e-g 44.71a s2f5 1030bc 1763ef 2793b-f 36.88b-d s3f0 693.3l 1258.7j 1952j 35.52c-e s3f1 803.3jk 1280j 2083.3ij 38.56bc s3f2 843.3ij 1413.3i 2256.7hi 37.37bc s3f3 893.3f-h 1550gh 2443.3gh 36.56b-e s3f4 913.3ef 1561.7g 2475gh 36.9b-d s3f5 860g-i 1466.7hi 2326.7h 36.96b-d lsd(0.05) 47.98 87.89 229.18 3.34 cv (%) 3.13 3.08 5.22 5.69 note: s1: 20 cm × 10 cm, s2: 30 cm × 10 cm, s3: 45 cm × 15 cm f0 = control, f1 = bari recommended npk, f2 = 5 t ha-1cowdung, f3 = 5 t ha-1cowdung + recommended npk, f4= 2.5 t ha-1cowdung + recommended npk, f5= 2.5 t ha-1cowdung + 1/2 recommended npk 0 5 10 15 20 25 30 35 40 s1 s2 s3 h a rv e st i n d e x ( % ) plant spacing 0 5 10 15 20 25 30 35 40 f0 f1 f2 f3 f4 f5 h a rv e st i n d e x ( % ) fertilizer dose b a 106 hosen et al. conclusion different yield and yield contributing parameters were significantly influenced by different spacing and fertilizer combinations. based on the above results it can be concluded that plant spacing at 30 cm × 10 cm along with the application of 2.5 t ha-1 cowdung with recommended doses of 40, 80, 30 kg ha-1 of urea, tsp, mop increased the overall productivity of mungbean. references agarico, b.c. 1985. effect of row spacing and time of weeding on the growth and yield of mungbean. ann. trop. res. 5(2): 83-90. agasimani, c.a., y.b. palled, h.d. naik, and g.k. kulkarni. 1984. response of groundnut cultivars to different spacing. indian j. agron. 29(2): 209-212. ahamed, k.u., k. nahar, n. m. rahmatullah, g. faruq, and m.a. alamgir. 2011. yield components and yield of different mungbean varieties as affected by row spacing. american-eurasian j. agro. 4(1): 1–5. ali, m.a., g. abbas, q. mohy-ud-din, k. ullah, g. abbas, and m. aslam. 2010. response of mungbean (vigna radiata) to phosphatic fertilizer under arid climate. j. anim. plant sci. 20(2): 83-86. asaduzzaman, m., f. karim, j. ullah and m. hasanuzzaman. 2008. response of mungbean (vigna radiata l.) to nitrogen and irrigation management. american-eurasian j. sci. res. 3: 40-43. aslam, m., h. nazim, m. zubair, s.b. hussain and m.s. baloch. 2010. integration of organic and inorganic sources of phosphorus for increased productivity of mungbean (vigna radiata l.). pak. j. agri. sci. 47(2): 111-114. barc (bangladesh agricultural research council). 2005. fertilizer recommendation guide. barc soils pub. no. 45. bangladesh agri. res. co, dhaka, bangladesh. bbs (bangladesh bureau of statistics). 2016. statistical yearbook of bangladesh.bangladesh bureau of statistics. statistics division, ministry of planning, govt. of peoples republic of bangladesh. dhaka. bangladesh. p.79 chaudhary, m.i., j. adu-gyamfi, h. saneoka, n.t. nguyen, r. suwa, s. kanai, h. el-shemy, d.a. lightfoot and k. fujita. 2008. the effect of phosphorus deficiency on nutrient uptake, nitrogen fixation and photosynthetic rate in mashbean, mungbean and soybean. acta phys. plantar. 30(4): 537-544. fao (food and agriculture organization). 2013. fao yearbook production. p.53. foysal, a.k.m., m. quamruzzaman, s.m.m. rashid, m. yeasmin and n. islam. 2016. effect of plant growth regulator and row spacing on yield of mungbean (vigna radiata l.). americaneurasian j. agric. environ. sci. 16(4): 814-819 ghasempour, r. and m. ashori. 2014. impact of various planting spaces and different levels of nitrogen fertilizer on yield and yield components of green beans [cultivated] under the weather of guilan province. indian j. fund. appl. life sci. 4(4): 2950-2956. haque, m.q., m.h. rahman, f. islam, j. rijpma and m.m. kadir. 2001. integrated nutrient management in relation to soil fertility and yield sustainability under wheat-mung-t. aman cropping pattern. j. biol. sci. 1(8): 731-734. hossen, m.m., a.s.m.i. hussai, a.a. zabir, m.j.h. biswas and m.r. islam. 2015. effect of nitrogenous fertilizer on yield of mungbean [vigna radiata (l.)wilczek] in patuakhali district of bangladesh. asian j. med. biol. res. 1(3): 508-517. effect of planting geometry and integrated fertilizer management on mungbean yield 107 kabir, m.h. and m.a.r. sarkar. 2008. seed yield of mungbean as affected by variety and plant spacing in kharif-i season. j. bangladesh agri. univ. 6(2): 239–244. kamal, m.m., m.a. hossain, f. islam and m.s.a. khan. 2001. response of mungbean to management practices for yield and quality seed production. bangladesh j. agric. res. 28(4): 501-511. khan, a. and m.a. malik. 2001. determining biological yield potential of different mungbean cultivars. j. biol. sci. 1: 575-576. mahboob, a. and m. asghar. 2002. effect of seed inoculum and different nitrogen level on the grain yield of mungbean. asian j. plant sci. 1(4): 314-315. mansoor, m., h. khan, m. ayaz, m. zubair and m.a. nadim. 2010. effect of different planting densities on some physiological parameters of mungbean. gomal univ. j. res. 26(2): 1–8. ministry of agriculture (moa). 2005. hand book of agricultural statistics, december, 2005, p: 14. ministry of agriculture, government of people’s repub., bangladesh, dhaka. moa (ministry of agriculture). 2014. monthly hand book of agricultural statistics, june. p. 57. naseri, r., k.h. fasihi, a. hatami and m.m. poursiahbidi. 2010. effect of planting pattern on yield, yield components, oil and protein contents in winter safflower cv. sina under rainfed conditions. iranian j. crops sci. 12(3): 227-238. nigamananda, b. and s. elamathi. 2007. studies on the time of nitrogen, application foliar spray of dap, and growth regulator on yield attributes, yield and economics of greengram (vigna radiata). intl. j. agric. sci. 3(1): 168-169. panwar, j.d.s. and g.s. sirohi. 1987. studies on effect of planting density on grain yield and its components on mungbean (vigna radiata l.). indian j. plant physiol. 30(4): 412-415. porwal, m.k., g.s. bhatnagar. and l.l. dhakar. 1991. response of soybean (glycine max) varieties to row spacing and photosynthesis. indian j. agro. 36: 553-555. rahman, m.a. and m.o. ali. 2007. the causes of decrease in pulse production and its remedy, p: 5. krishibiplop (a fortnightly magazine in bengali), published on 15 november, 2007. 279 east hazipara, rampura, dhaka-1219, bangladesh. rasul, f., m.a. cheema, a. sattar, m.f. saleem and m.a. wahid. 2012. evaluating the performance of three mungbean varieties grown under varying inter-row spacing. j. anim. plant sci. 22(4): 1030-1035. rautaray. s., b.c. ghoshm and b.n. mittra. 2003. effect of fresh, organic wastes and chemical fertilizers on yield, nutrient uptake, heavy metal content and residual fertility in a rice-mustard cropping sequence under acid leteritic soils. bioresource tech. 90(3): 275-283. razzaque, m.a., m.m. haque, m.a. karim, a.r.m. solaiman and m.m. rahman. 2015. effect of nitrogen on different genotypes of mungbean as affected by nitrogen level in low fertile soil. bangladesh j. agril. res. 40(4): 619-628. singh, g., h. sekhon, j. sandhu, s. singh, r. gumber and a. randhawa. 2003. effect of location and seed rate on three genotypes of mungbean. trop. sci. 43(3): 116–120. srinivas, m., m. shaik and s. mohammad. 2002. performance of greengram (vigna radiata l. wilczek) and response functions as influenced by different level of nitrogen and phosphorus. crop res. hisar 24(3): 458-462. sullivan, p. 2003. intercropping principles and production practices. fayetteville. retrieved from http://pctanzania.org/ repository/ environment/ agriculture/ intercropping. usda-ars. 2012. germplasm resources information network (grin). wallingford, w. 1980. function of potassium in plants. pp. 10-27 in: potassium for agriculture. potash and phosphate inst., atlanta, georgia. bangladesh agron. j. 2025, 28(1): 8-16 response of fertilizer and weed management on black cumin m. z. ali*, a. a. begum, s. s. kakon, m. r. karim and m. a. h. khan agronomy division, bangladesh agricultural research institute, joydebpur, gazipur-1701, bangladesh *corresponding author, email: zabiedbd71@gmail.com (received: 07 october 2025, accepted: 20 november 2025) keywords: nitrogen, phosphorus, potassium, recommended fertilizer dose, weed management abstract the experiment was conducted at agronomy research field of bangladesh agricultural research institute, gazipur during 2018-2019 and 2019-20 to find out the optimum fertilizer dose and appropriate weed management method for getting higher yield and economic return of black cumin. the treatments were t1= stb (soil test basis fertilizer dose, frg, 2018) 6024-49-13-0-1 kg ha−1 of npksznb and two hand weeding at 30 days after emergence (dae) and 50 dae of black cumin, t2= stb + 25% of n-p-k kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t3= stb + 50% of n-p-k kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t4= stb and two hand spading at 30 dae and 50 dae of black cumin, t5= stb + 25% of n-p-k kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin ,t6= stb + 50% of n-p-k kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin and t7 = native nutrient and no weeding (control). the highest weed control efficiency % (wce) 83.68 and 85.23% at 30 dae of black cumin and 93.62% and 92.57% at 50 dae of black cumin was found in t3 treatment (two hand weeding at 30 dae of black cumin and 50 dae of black cumin with stb + 50% of npk kg ha−1 fertilizer dose) in 2018-2019 and 2019-2020, respectively followed by t2 (82,35 to 82.74% and 92.24 to 91.24%) treatment at 30 and 50 dae of black cumin and in 2018-19 and 201920 respectively. results showed that treatment t3 (stb + 50% of n-p-k kg ha−1 and two hand weeding at 30 and 50 dae of black cumin) produced the highest seed yield 953.75 kg ha−1 but in case of higher benefit cost ratio 2.69 was obtained from t4 treatment (soil test basis fertilizer dose: 60-24-49-13-0-1 kg ha−1 of n-p-k-s-zn-b kg ha−1 and two hand spading at 30 and 50 dae of black cumin) due to lower cost of production. introduction black cumin (nigella sativa), known as kalozira, is one of the important spice crops (abadi et al., 2015) in bangladesh, it is popular among the people for serving a wide range of medicinal purposes. it is widely cultivated throughout south europe, syria, egypt, saudi arabia, iran, pakistan, india and turkey (riaz et al., 1996). the seed contain 30-35% of oil which has several uses for pharmaceutical and food industries (ustun et al., 1990). the ripe seed contains 23% protein, 0.39% fat, 4.99% starch and 5.44% raw fiber (zargari, 1990). among the seed spices grown, black cumin or nigella is considered as a miraculous spice having very important medicinal values apart from its intrinsic flavor (aliyu, 2003). it is also appreciated as magical herb for its ability to treat allergies, asthma, and immune disorders (naz, 2011). for these reasons, there is a great demand of black cumin in consumer level. in bangladesh, winter season is the favorable environment for the black cumin cultivation. crop management factors such as fertilizer and weed management are essential to increase yield and quality of seed (singh and goswami, 2000). weed control reduce potential environmental contamination and will reduce crop weed completion and ultimately increase the yield as well as black cumin yield (nadeem et al., 2013). now a day, people become conscious about their health and as a result this type of ayurvedic medicinal and rare mailto:zabiedbd71@gmail.com response of fertilizer and weed management on black cumin 9 condiments is in great demand and has thus become a paying cash crop. to meet its increasing demand the productivity must be increased. hence, the experiment was conducted to find out optimum fertilizer dose and appropriate weed management practice for obtaining higher yield and economic return. materials and methods the experiment was conducted at the research field of agronomy division bari, joydebpur, gazipur during rabi season of 2018-19 and 2019-20, respectively. the soil of the research area belongs to aez-28. the soil was clay loam with ph 6.3. soil samples of the experimental plots were collected and analyzed. the chemical properties of experimental soil are presented in table 1. table 1. chemical properties of experimental soil (initial) ph om (%) total n (%) available p (µg ml−1) exchangeable k (meq 100g−1 soil) available s (µg ml−1) available zn (µg ml−1) available b (µg ml−1) 6.3 1.910 0.092 7.750 0.079 8.400 1.620 0.175 vl l l vl l o l critical levels 7.0 0.12 10.00 0.60 0.20 l= low, vl= very low, o = optimum seven treatments viz., t1= stb (soil test basis fertilizer dose, frg, 2018) 60-24-49-130-1 kg ha−1 of npksznb and two hand weeding at 30 days after emergence (dae) and 50 dae of black cumin, t2= stb + 25% of n-p-k kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t3= stb + 50% of n-p-k kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t4= stb and two hand spading at 30 dae and 50 dae of black cumin, t5= stb + 25% of n-p-k kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin ,t6= stb + 50% of n-p-k kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin and t7 = native nutrient and no weeding (control) were used in the study as treatment variable. the experiment was laid out in a randomized complete block design (rcbd) with three replications. the unit plot size was 3 m × 4 m. seeds of bari kalijira-1 were sown on 25 november, 2018 and 23 november, 2019 with maintaining spacing 30 cm × 5 cm. full amount of triple super phosphate (tsp), muriate of potash (mop), gypsum, zinc sulphate and boric acid were applied at the time of final land preparation. the remaining n (urea) was top dressed in two equal splits at 30 and 50 days after sowing (das). in addition, 5 t ha−1 of cowdung were applied before land preparation. a light irrigation was given after sowing of seeds for germination. four irrigations were given to crop at 15, 30, 45 and 60 dae. thinning was done at 10 dae and weeding was done as per treatments. for dry matter estimation, 10 plants were sampled at 30, 45, 60, 75 dae and at harvest. weed samples were collected using 50 cm × 50 cm quadrate, from randomly selected four places from each plot at 30 and 50 dae of black cumin. number and dry weight of weeds were recorded carefully. weed control efficiency (wce) was calculated according to following formula: wce (%) =       − a ba ×100; where, a = dry weight of weeds in no weeding plots and b = dry weight of weeds in treated plots. bari kalijira-1 was harvested on 29 may, 2019 and 28 may, 2020 respectively. the yield component data was taken from 10 randomly selected plants prior to harvest from each plot. 10 ali et al. at harvest, the yield data was recorded plot wise. yield and yield contributing characters were recorded and pooled data analyzed statistically and means separations were done by lsd test at 5% level of significance. results and discussion number of weeds m−2, weed dry weight and weed control efficiency in both the year (2018-19 and 2019-2020, respectively) number of weeds m−2, weed dry weight (g m−2) and wce (%) were affected by different fertilizer dose and weed management practices are presented in table 2. table 2. effect of different doses of fertilizer and weed management practice on number of weeds m−2 in 2018-19 and 2019-20 treatments 30 dae 50 dae weed m−2 (no.) weed m−2 (no.) 2018-19 2019-20 2018-19 2019-2020 t1 91 102 46 61 t2 98 105 70 82 t3 104 108 59 70 t4 120 134 60 75 t5 120 134 60 75 t6 109 116 67 77 t7 127 178 211 276 anguli (digitaria spp), durba (cynodon dactylon), helencha (enhydra fluctuans), mutha (cyperus rotundus) and shama (echinochola crusgali) were found the most dominant weed in the black cumin field. the number of weeds m−2 ranged from 91 to 127 m−2 during 2018-19 and 102 to 178 m−2 during 2019-20 at 30 daes of black cumin. at 50 daes of black cumin number of weeds m−2 ranged from 46 to 211 m−2 during 2018-19 and 61 to 276 m−2 during 2019-20, respectively in different fertilizer dose and weed management practice. table 3. effect of different doses of fertilizer and weed management practice on weed dry weight and weed control efficiency over time in black cumin field during rabi season of 2018-2019 and 2019-20. treatments weed dry weight (g m−2) weed control efficiency (%) 30 dae 50 dae 30 dae 50 dae 2018-19 2019-20 2018-19 2019-20 2018-19 2019-20 2018-19 2019-20 t1 7.95 8.78 5.80 6.84 81.17 81.01 91.21 90.30 t2 7.45 7.98 5.12 6.13 82.35 82.74 92.24 91.30 t3 6.92 6.83 4.20 5.24 83.61 85.23 93.62 92.57 t4 9.92 10.78 7.90 8.45 76.50 76.68 88.02 88.01 t5 8.82 9.78 7.00 8.98 79.10 78.84 89.38 87.26 t6 8.12 8.65 6.89 7.35 80.76 81.29 89.55 89.57 t7 42.41 46.23 65.93 70.48 note: t1= stb (soil test basis fertilizer dose, frg, 2018) 60-24-49-13-0-1 kg ha−1 of npksznb and two hand weeding at 30 dae and 50 dae of black cumin, t2= stb + 25% of npk kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t3= stb + 50% of n-p-k kg ha−1 and two hand weeding at 30 dae and 50 dae of black cumin, t4= stb and two hand spading at 30 dae and 50 dae of black cumin, t5= stb + 25% of npk kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin ,t6= stb + 50% of npk kg ha−1 and two hand spading at 30 dae and 50 dae of black cumin and t7 = native nutrient and no weeding (control). response of fertilizer and weed management on black cumin 11 among the treatments the lowest number of weed m−2 (91 and 102 m−2) was found in the treatment t1 followed by t2 (98 and 105 m−2) at 30 dae of black cumin during 2018-19 and 2019-20, respectively. at 50 dae of black cumin the lowest number of weeds m−2 was obtained from t1 treatment (46 and 61 m−2) followed by t3 (59 and 70 m−2). the highest number of weeds m−2 (127 and 178 m−2 at 30 dae and 211 and 276 m−2 at 50 dae was recorded in t7 (native nutrient and no weeding, control plots) during 2018-19 and 2019-20, respectively. the maximum weed dry weight was 42.41 and 46.23 g m−2 at 30 dae of black cumin and 65.93 g m−2 and 70.48 g m−2 at 50 dae of black cumin was recorded in treatment t7 treatment (native nutrient and no weeding: control plots) in 2018-19 and 2019-20, respectively (table. 3). the minimum weed dry weight (6.92 g m−2 and 6.83 g m−2) was recorded in t3 treatment at 30 dae of black cumin in 2018-19 and 2019-20, respectively. similarly at 50 dae of black cumin the minimum weed dry weight 4.20 g m−2 and 5.24 g m−2 was obtained from t3 treatment during 2018-19 and 2019-20, respectively. higher weed density and dry weight decrease the seed yield of black cumin. similar findings were observed by sarandon et al. (2002). the variation in wce was observed among the different treatments. the highest wce 83.61 85.23% at 30 dae of black cumin and 93.62 and 92.57% at 50 dae of black cumin was found in t3 treatment (two hand weeding at 30 and 50 dae of black cumin with stb + 50% of n-p-k kg ha−1 fertilizer dose) respectively followed by t2 and t1 and treatments during 2018-19 and 2019-20, respectively (table 3). first flower bud initiation, capsule setting and capsule ripening days in 50% plant different fertilizer levels and weed management slightly influence the first flower bud initiation day in 50% plants of black cumin in both the year (table 4). table 4. effect of fertilizer and weed management on first flower bud initiation, capsule setting and capsule ripening days in 50% plant of black cumin in 2018-19 and 2019-20 treatments first flower bud initiation days in 50% plant (das) capsule setting days in 50% plant (das) capsule ripening days in 50% plant (das) 2018-19 201920 2018-19 201920 2018-19 201920 t1 79 78 83 83 132 131 t2 78 78 84 83 133 131 t3 82 81 86 85 134 133 t4 77 76 83 83 132 131 t5 77 76 83 83 133 132 t6 78 77 86 84 134 132 t7 76 75 76 76 128 126 among the treatments t3 took the maximum days (82 and 81 das) for first flower bud initiation in 50% plants, whereas t7 (native nutrient and no weeding: control) treatment took the minimum days (76 and 75 das) during 2018-19 and 2019-29, respectively. capsule setting days in 50% plant influence among the different treatments (table 4). t3 treatment took the longest time (86 and 85 das) for capsule setting in 50% plant, whereas, control treatment t7 took the shortest time 76 das in both the years. capsule ripening time in 50% plant among the treatment combinations, t3 treatment took maximum time 134 das and 133 das whereas t7 treatment (native nutrient and no weeding: control) expressed the minimum time 128 das and 126 das during 2018-19 and 2019-20, respectively. total dry matter the yield of a crop is mainly determined by the accumulation of dry matter and its partitioning into the economic sink. the pattern of dry matter accumulation in black cumin over 12 ali et al. time was influenced by different fertilizer dose and weed management practice (fig. 1). total dry matter g m−2 of black cumin influenced by the different dose of fertilizer and weed management method. total dry matter was increased gradually with the different level of applied fertilizer and weed management method in both years. total dry matter increased slowly up to 60 dae there after dry matter accumulation increased rapidly up to harvest. among the treatment combinations t3 treatment (stb + 50% of npk) produced the maximum total dry matter 26.40 g m−2 and 23.40 g m−2 at 30 dae of black cumin and t7 treatment (native nutrient and no weeding: control) produced the minimum tdm 19.2 g m−2 and 16.20 during 2018-19 and 2019-20, respectively. at 45 dae of black cumin t3 treatment similarly produced the maximum tdm (41.40 g m−2 and 36.00 g m−2), whereas t7 treatment (control) produced minimum total dry matter weight (24.60 and 23.98 g m−2) during 2018-19 and 2019-20, respectively. at 60 dae of black cumin maximum total dry matter weight (73.40 and 70.80 g m−2) was recorded in t3 treatment and minimum total dry matter weight (40.80 and 37.40 g m−2) was recorded in t7 treatment with no fertilizer and no weeding. similar trend also observed at 75 dae of black cumin. higher total dry matter weight 196.40 g m−2 in 2018-19 and 186.43 g m−2 in 2019-2020, respectively was obtained from in t3 treatment at harvest with stb + 50% of npk fertilizer dose and two hand weeding at 30 and 50 dae of black cumin. no fertilizer and no weeding showed the minimum dry matter weight 131.20 g m−2 and 116.23 g m−2 during 2018-19 and 2019-2020, respectively. similar findings were also observed by ali et al. (2015) in black cumin. fig. 1. total dry matter (tdm g m−2) of black cumin as influenced by different fertilizer dose and weeding method. relationship between seed yield of black cumin with fertilizer dose there was a positive linear correlation between seed yield of black cumin with different fertilizer doses (fig. 2).the regression line (y = 1.771x + 605.9, r2 = 0.87) that means the correlation of coefficient (x) was 1.771 stated that seed yield of black cumin increase at the rate of 1.771 kg ha−1 for per unit change of fertilizer levels during 2018-19 and 2019-20 also found the similar results that means there was a positive linear correlation between seed yield of black cumin with different fertilizer doses (fig. 2). the regression line (y = 1.935x + 541.7, r2 = 0.868) that means the correlation of coefficient (x) was 1.935 stated that seed yield of black cumin increases at the rate of 1.935 kg ha−1 for per unit change of fertilizer levels during 2019-20. the coefficient of determination (r2 = 0.87) and (r2 =0.867) value indicated that 0.87 and 0.867% during 2018-19 and 2019-20 respectively on seed yield of black cumin was attributed due to different doses of fertilizer. thus, the result indicated that increasing fertilizer dose increase the seed yield of black cumin. these findings are in agreement with those of tuncturk et al. (2012). dae 2018-2019 dae 2019-2020 0 50 100 150 200 250 30 dae 45 dae 60 dae 75 dae harvest t1 t2 t3 t4 t5 t6 t7 t o ta l d ry m at te r (t d m ) g m − 2 0 20 40 60 80 100 120 140 160 180 200 30 dae 45 dae 60 dae 75 dae harvest t1 t2 t3 t4 t5 t6 t7 t o ta l d ry m at te r (t d m ) g m − 2 response of fertilizer and weed management on black cumin 13 fig. 2. functional relationship between applied different fertilizer dose and seed yield of black cumin in 2018-19 and 2019-20. relationship between seed yield of black cumin with weed dry weight at harvest there was a negative linear correlation between seed yield of black cumin with weed dry weight at harvest (fig. 3). in 2018-19 the regression line (y = −0.538x + 975.57, r2 = 0.9598) that means the correlation of coefficient (x) was −0.538 stated that seed yield decrease at the rate of −0.538 kg ha−1 for per kg increase of weed dry weight at harvest and in 2019-20 and the regression line (y = −0.5981x + 957.17, r2 = 0.9655) that means the correlation of coefficient (x) was −0.5981 stated that seed yield decrease at the rate of −0.5981 kg ha−1 for per kg increase of weed dry weight at harvest. the coefficient of determination (r2 = 0.9598) and (r2= 0.9655) value indicated that 0.9598% and 0.9655% seed yield of black cumin was attributed due to dry weight of weed during 2018-19 and 2019-20, respectively. thus, the results indicated that increasing dry weight of weeds decreasing the seed yield of black cumin. these findings were in agreement with those of sarandon et al. (2002), ciuberkis et al. (2004) and mubeen et al. (2009). fig. 3. functional relationship between seed yield of black cumin and weed dry weight at harvest in 2018-19 and 2019-20. total applied nutrient (kg ha−1) in 2018-19. total applied nutrient (kg ha−1) in 2019-20. y = 1.7716x + 605.92 r² = 0.87 y ie ld ( k g h a− 1 ) y = 1.9352x + 541.73 r² = 0.8689 y ie ld ( k g h a − 1 ) weed dry weight at harvest in 2018-19. weed dry weight at harvest in 2019-20. y = -0.538x + 975.57 r² = 0.9598 0 500 1000 1500 0 200 400 600 800 y ie ld ( k g h a− 1 ) y = -0.5981x + 957.17 r² = 0.9655 0 500 1000 1500 0 200 400 600 800 y ie ld ( k g h a− 1 ) 14 ali et al. effect on yield and yield contributing characters of black cumin yield and yield components of black cumin were statistically influenced by different doses of fertilizer and weed management method (table 5). table 5. yield attributes of bari kalijira-1 as influenced by different doses of fertilizer and weed management the tallest plant at harvest (56.47 cm) was observed in t3 treatment which was statistically similar with that of t5 (54.93 cm), t2 (53.32 cm), t1 (52.30) treatments and the shortest plant (33.06 cm) in t7 treatment (no fertilizer and no weeding). valadabadi and aliabadi (2011) found plant height of black cumin to range from be 58 to 82 cm. plant heights might be controlled genetically, and/or environmental factors. the reason may be due to higher doses of fertilizer application which itself increases plant growth by promoting processes such as cell division, cell enlargement, metabolic processes. t3 treatment produced the maximum number of branches plant−1 (7.31) which was statically similar with t2 (7.11) and t1 (6.67) treatments. t7 treatment gave the minimum branches plant−1 (3.69). tuncturk et al. (2012) found significant influence of fertilizer levels and weed management on the number of branches plant−1 in black cumin. at harvest t3 treatment gave the maximum number of capsule plant−1 (21.27) which was statistically identical with that of t2 (19.64) treatment. hammo and al-atrakchii (2006) and tuncturk et al. (2012) also reported increased number of capsule plant−1 of black cumin with increased of fertilizer levels. the lowest number of capsule plant−1 of black cumin was obtained from control t7 (11.70) treatment. the maximum number of capsule plant−1 at harvest (89.03) was obtained from t3 treatment which was statistically identical with that of t2 (82.23) treatment. among the treatments t7 treatment (control) gave the minimum number of capsule plant−1 (42.38). this result was correlated was in agreement with the findings of toncer and kizil (2004) who reported that, number of capsule plant−1 varied from 85.7 to 92.8. the maximum capsule length at harvest (0. 4 cm) was recorded from t3 treatment which was statistically similar with that of t2 (0.33 cm), t1 (0.32), t6 (0.31 cm), and t5 (30 cm) and t4 (30 cm) treatments whereas the lowest capsule length was obtained from (0.19 cm) from t7 treatment (control). the highest capsule diameter also follows the similar trend of capsule length. the highest capsule diameter (0.20 cm) was obtained from t3 treatment and it was at par with that of t2 and t1 treatments. treatment t7 (control) showed the minimum capsule diameter (0.09 cm). 1000 seed weight is an important yield contributing character. the 1000 seed weight of black cumin significantly influenced by different fertilizer dose and weed management practices. significantly the highest 1000 seed weight (3.31g) was obtained from t3 treatment which was at par with that of t2 (3.27 g) and t1 (3.24 g) treatments. the lowest 1000 seed weight 1.72 g was obtained from t7 treatment (control). kaheni et al. (2013) also found significant effect of different fertilizer levels on treatments plant height (cm) branch plant−1 (no.) capsule plant−1 (no.) seed capsule−1 (no.) length of capsule (cm) diameter of capsule (cm) 1000 seed weight (g) seed yield (kg ha−1) t1 52.30 6.67 18.57 77.30 0.32 0.14 3.24 933.32 t2 53.32 7.11 19.64 82.23 0.33 0.17 3.27 946.41 t3 56.47 7.31 21.27 89.03 0.34 0.20 3.31 953.75 t4 45.10 6.23 16.55 61.53 0.30 0.11 2.52 859.87 t5 54.93 6.31 16.86 65.23 0.30 0.13 2.70 898.25 t6 50.63 6.38 17.76 71.90 0.31 0.13 2.75 928.04 t7 33.06 3.69 11.70 42.38 0.19 0.09 1.72 565.54 lsd (0.05) 12.64 0.78 1.83 8.97 0.06 0.06 0.48 114.50 cv (%) 14.17 7.01 5.87 7.21 3.27 11.31 9.73 7.41 response of fertilizer and weed management on black cumin 15 thousand seed weight of black cumin. seed yield (kg ha−1) of black cumin significantly influenced by different dose of fertilizer and weed management method. the maximum yield (953.75 kg ha−1) was obtained from t3 treatment (stb + 50% of npk along with two hand weeding at 30 and 60 dae of black cumin) followed by t2 (946.41 kg ha−1), t1 (933.32 kg ha−1), t6 (928.04 kg ha−1), t5 (898.25 kg ha−1) and t4 (859.87 kg ha−1) treatments. the lowest yield (565.54 kg ha−1) was obtained from control treatment t7 (no fertilizer and no weeding). tuncturk et al. (2012) and (valadabadi and aliabadi, 2011) reported that increasing fertilizer doses and properly weed management positively influenced seed yields in black cumin. economic performance from the cost-benefit analysis it was found that the maximum gross return (tk. 2,38,437 ha−1) was obtained from t3 treatment followed by treatments t2 (tk. 2,36,603 ha−1) and t1 (tk. 2,33,330 ha−1) (table. 6). the highest cost of production was recorded in t3 treatment (tk. 94,000 ha−1) due to high labour and fertilizer cost. the highest gross margin of (tk. 1,44,603 ha−1) was obtained from t2 treatment followed by t3 (tk. 1,44,437 ha−1) and t6 (tk. 1,44,010 ha−1) treatments. the highest bcr 2.69 was obtained from t4 treatment (stb fertilizer dose along with two hand spading at 30 and 50 dae of black cumin) due to lower cost of cultivation (table. 6) followed by t5 (2.67) and t6 (2.64). the lowest bcr (1.89) was recorded in t7 (no fertilizer and no weeding) treatment. table 6. economic performance of different doses of fertilizer and weed management on black cumin in 2018-2019 and 2019-2020 (average data of two years) treatments black cumin yield (kg ha−1) gross return (tk. ha−1) total cost of production (tk. ha−1) gross margin (tk. ha−1) benefit cost ratio (bcr) t1 933.32 2,33,330 90,000 1,43,330 2.59 t2 946.41 2,36,603 92,000 1,44,603 2.57 t3 953.75 2,38,437 94,000 1,44,437 2.54 t4 859.87 2,14,967 80,000 1,34,967 2.69 t5 898.25 2,24,563 84,000 1,40,563 2.67 t6 928.04 2,32,010 88,000 1,44,010 2.64 t7 565.54 1,41,386 75,000 66,386 1.89 note: ureatk. 16 kg−1, tsptk. 25 kg−1, moptk. 15 kg−1, gypsumtk. 12 kg−1, zinc sulphatetk. 175 kg−1, boric acidtk. 200 kg−1, labourtk. 500 man−1 day−1, irrigationtk. 3,000 ha−1 irrigation−1, seedtk. 400 kg−1 and sale price of seed tk. 250 kg−1. conclusion fertilizer dose @ 90-36-73-13-0-1 kg ha−1 of n-p-k-s-zn-b and two hand weeding at 30 and 50 dae of black cumin produced higher seed yield (953.75 kg ha−1) of black cumin but highest marginal bcr 2.69 was obtained from fertilizer dose @ 60-24-49-13-0-1 kg ha−1 of n pksznb (soil test basis fertilizer dose) and two hand spading at 30 and 50 dae of black cumin due to lower cost of production. references abadi, b.h.m., h.r ganjali and h.r mobasser. 2015. effect of mycorrhiza and phosphorous fertilizer on some characteristics of black cumin. biol. forum int. j. 7(1): 1115-1120. aliyu, l. 2003. effect of manure type and rate on growth, yield and yield components of pepper. j. sustain. agric. environ. 5: 92-98. 16 ali et al. ciuberkis, s., b. stasys, r. steponas and j. felix. 2004. effect of weed emergence time and intervals of weed and crop competition on potato yield. j. weed tech. 21(1): 213-218. frg. 2018. bangladesh agricultural research council (barc), farmgate, dhaka 1215. pp. 113. hammo, y.h. and a.o. al-atrakchii. 2006. effect of nitrogen, phosphorus fertilizers and plant distances on growth of (nigella sativa l.). mesopotamia j. agric. 34(3): 17-26. kaheni, a., s.h.r. ramazani, h.r. ganjali and h.r. mobaser. 2013. effect of nitrogen fertilizer and plant density on yield and its components in cumin (cuminum cyminum l.) in south khorasan province. int. j. agric. crop sci. 6(5): 248-251. nadeem, m.a., a. tanveer, t. naqqash, a.j. jhala and k. mubeen. 2013. determining critical weed competition periods for black seed. j. anim. plant sci. 23(1): 216-221. ali, m.m.k., m.a. hasan and m.r. islam. 2015. influence of fertilizer levels on the growth and yield of black cumin (nigella sativa l.). the agriculturists. 13(2): 97-104. mubeen, k., a. tanveer, m.a. nadeem, n. sarwar and m. shahzad. 2009. critical period of weed-crop competition in fennel (foeniculum vulgare mill.) pakistan j. weed sci. res. 15(2-3): 171-181. naz, h., 2011. nigella sativa: the miraculous herb. pak. j. biochem. mol. biol. 44(1): 44-48. riaz, m., m. sayed and f.m. chaudhary. 1996. chemistry of the medicinal plants of the genus nigella. hamdard medicus. 39: 40-45. sarandon, m.v., g.e. sanchez-vallduvi, c.c. flores and r.c. barreyro. 2002. competence of natural weed community at different stages black seed crop development. crop res. (hisar). 23(2): 269-276. singh, k.k. and t.k. goswami. 2000. thermal properties of cumin seed. j. food eng. 45(4): 181-187. toncer, o. and s. kizil. 2004. effect of seed rate on agronomic and technologies characters of nigella sativa l. int. j. agric. biol. 6(3): 529-532. tuncturk, r., m. tuncturk and v. ciftci. 2012. the effects of varying nitrogen doses on yield and some yield components of black cumin (nigella sativa l.). adv. environ. biol. 6(2): 855-858. ustun, g., l. kent, n. cekin and h. civelekoglu. 1990. investigation of the technological properties of nigella sativa (black cumin) seed oil. j. am. oil chem. soc. 67(12): 71-86. valadabadi, s.a. and h.f. aliabadi. 2011. investigation of bio-fertilizers influence on quantity and quality characteristics in nigella sativa l. j. hortic. for. 3(3): 88-92 zargari, a. 1990. herbal plants. tehran university publication, tehran, iran, pp 33-34. blank page bangladesh agron. j. 2025, 28(2): 66-88 a meta-analysis of brri conducted ten years field research on transplanted aman rice in bangladesh n. parvin1*, m. a. salam2, m. u. salam3, m. a. kader2, b. nessa4, t. araf5 1senior scientific officer, rice farming systems division, bangladesh rice research institute, gazipur-1701 2professor, department of agronomy, bangladesh agricultural university, mymensingh-2202 3freelance consultant, 115/3, east bhurulia, joydebpur, gazipur -1700, bangladesh 4senior scientific officer and head, sunamganj regional station, bangladesh rice research institute, shantiganj, sunamganj3000 5scientific officer, rice farming systems division, bangladesh rice research institute, gazipur-1701 *corresponding author, e-mail: nargisrfs@gmail.com (received: 20 october 2025, accepted: 23 november 2025) keywords: brri, hill density, meta-analysis, rice, seeding age, transplanting time, variety, yield abstract in the cropping systems of bangladesh, t. aman rice has special significance. on the bright side, the crop is grown utilizing monsoonal rain water. on the hind side, it faces natural hazards such as early and terminal drought, and both early and late flooding. therefore, variety choice and agronomic management are the key considerations for a successful crop harvest. bangladesh rice research institute (brri), the prime rice research institute of the country, routinely conducts large number of trials across the country, accounting for diverse environments, which include performance of varieties and management practices. this study has compiled the body of this knowledge through meta-analysis to generate information using 10-year’s meta-data were gathered during the period of 2010 through to 2019. the average yield in meta-data was 7.37 percent higher than national average of t. aman rice yield of bangladesh. varieties under high yield potential (hyp) category averaged yield of 4.34 t ha−1) and some newer varieties like brri dhan72, brri dhan79, brri dhan87, brri dhan76, brri dhan78, brri dhan80, brri dhan90 produced higher yield (above 4.5 t ha−1). again, many old varieties such as br 3, br 4, br 10, br 11, brri dhan31, brri dhan32 produce yield close to 4.5 t ha−1. this study did not find a consistent pattern of response of the three measured management components – transplanting time, seedling age and seedling density. environmental response on the yield of rice varieties varies between years and locations of the experimentations (environments), indicating environment played a prominent role on yield. eventually, this study is enough to create the thirst of researchers in the rice research field here some further feasibility of rice yield improvement would emerge from the study of meta-analysis. the results provide a clear message to stakeholders that variety-environment-management synchronized approach is essential for improved yields of t. aman rice in bangladesh. introduction agriculture, dominated by crop, is one of the major sectors of developing economy of bangladesh. among the crops, cereals occupy about 75 percent of total cropped area, of which about 96 percent belongs to rice (sarwar and biswas, 2021). according to sayeed and yunus (2018), rice sector provides about 70 percent of agricultural gdp. rice is grown in bangladesh throughout the year and centred around three seasons aus, aman (almost entirely transplanted aman (t. aman) and boro. while the seasons overlap, the temporal distribution largely follows as mid-march to mid-july for aus, mid-july to mid-november for t. aman and mid-november to mid-march for boro. the seasons accounted for 8.87, 49.31 and 41.82 percent by area and 7.30, 40.93 and percent 51.77 by production for aus, t. aman and boro, respectively. a meta-analysis of brri conducted ten years field research on transplanted aman rice 67 in the cropping systems of bangladesh, t. aman rice has special significance. on the bright side, the crop is grown utilizing monsoonal rain water. on the hind side, it faces natural hazards such as early and terminal drought, and both early and late flooding. therefore, variety choice and agronomic management are the key considerations for a successful crop harvest. bangladesh rice research institute (brri), the prime rice research institute of the country, routinely conducts large number of trials across the country, accounting for diverse environments, which include performance of varieties and management practices. this body of knowledge requires compilation, in a methodical format, to generate information. garg et al. (2008) and hillebrand et al. (2010) have put forward that meta-analysis is a widely used statistical technique that systematically integrates data from multiple related but independent studies and analyses them together to better estimate the real impact of specific interventions or exposures on specific outcomes. this technique allows researchers to draw more robust conclusions than via the analysis of any separate study (chao et al., 2016). as mentioned by hernandez et al. (2020), individual studies are often insufficient to provide clear results, while larger studies often fail to fully estimate the difference in the risk of rare adverse events. therefore, a systematic combination of multiple research results, even if they are uncertain or contradictory, helps to more clearly identify true measurements (andrel et al., 2009; higgins et al., 2002; hillebrand et al., 2010). keeping the views in mind, this study explored the synthesizing a decade-long research-generated rice production technology for t. aman rice. materials and methods gathering meta-data ten-year’s meta-data for the period of 2010 through to 2019 were gathered during the meta-analysis. those data included the experiments conducted by the bangladesh rice research institute (brri) at the headquarter and regional stations, and documented in published annual reports (ars) and/or unpublished annual research review reports (arrrs). data were sourced from: brri 2013a; brri 2013b; brri 2013c; brri 2013d; brri 2013e; brri 2013f; brri 2013g; brri 2013h; brri 2013i; brri 2013j; brri 2013k; brri 2013l; brri 2013m; brri 2014a; brri 2014b; brri 2014c; brri 2014d; brri 2014e, brri 2014f; brri 2014g; brri 2014h ; brri 2014i; brri 2014j; brri 2014k; brri 2014l; brri 2014m; brri 2014n; brri 2014o; brri 2014p; brri 2014q; brri 2014r; brri 2014s; brri 2014t; brri 2014u; brri 2014v; brri 2014w; brri 2014x; brri 2014y; brri 2014z; brri 2014aa; brri 2014ab; brri 2014ac; brri 2014ad; brri 2014ae; brri 2014af; brri 2014ag; brri 2014ah; brri 2014ai; brri 2014aj; brri 2014ak; brri 2014al; 2014am; brri 2014an; brri 2014ao; brri 2014ap; brri 2014aq; brri 2014ar; brri 2014as; brri 2014at; 2014au; brri 2015a; brri 2015b; brri 2015c; brri 2015d; brri 2015e; brri 2015f; brri 2015g; brri 2015h; brri 2015i; brri 2015j; brri 2015k; brri 2015l; brri 2015m; brri 2015n; brri 2015o; brri 2015p; brri 2015q; brri 2015r; brri 2015s; brri 2015t; brri 2015u; brri 2016a; brri 2016b; brri 2016c; brri 2016d; brri 2016e; brri 2016f; brri 2016g; brri 2016h; brri 2016i; brri 2016j; brri 2016k; brri 2016l; brri 2016m; brri 2016n; brri 2016o; brri 2016p; brri 2016q; brri 2016r; brri 2016s; brri 2016t; brri 2016u; brri 2016 v; brri 2016 w; brri 2016 x; brri 2016 y; brri 2016 z; brri 2016 aa; brri 2016 ab; brri 2016ab; brri 2016ac; brri 2016ad; brri 2016ae; brri 2016af; brri 2016ag; brri 2016ah; brri 2016ai; brri 2016aj; brri 2016ak; brri 2016al; 2016am; brri 2016an; brri 2016ao; brri 2016ap; brri 2016aq; brri 2016ar; brri 2016as; brri 2016at; 2016au; 2016av; brri 2017b; brri 2017c; brri 2017d; brri 2017e; brri 2017f; brri 2017g; brri 2017h; brri 2017i; brri 2017j; brri 2017k; brri 2017l; brri 2017m; brri 2017n; brri 2017o; brri 2017p; brri 2018a; brri 2018b; brri 2018c; brri 2018d; brri 2018e; brri 2018f; brri 2018g; brri 2018h; brri 2018i; brri 2018j; brri 2018k; 68 parvin et al. brri 2018l; brri 2018m; brri 2018n; brri 2018o; brri 2018p; brri 2018q; brri 2018r; brri 2018s; brri 2019a; brri 2019b; brri 2019c; brri 2019d; brri 2019e; brri 2019f; brri 2019g; brri 2019h; brri 2019i; brri 2019j; brri 2019k; brri 2019l; brri 2019m; brri 2019n; brri 2019o. the ars and arrrs were available electronically. brri sourced-data were used because of its national recognition as the prime and dedicated rice research institute, its extensive research coverage across the nation’s diverse agroecosystems, and relatively easy availability research data. data were searched in the sources in the following orderly criteria: i. the experiments conducted only in t. aman season in conformity of the season for which the present study was undertaken; ii. treatments of the experiments included named inbreed ‘variety’ or ‘varieties; iii. under criterion, treatments included one or more of the three sub-treatments: ‘transplanting time’, ‘seedling age’ and ‘hill density’. the above search criteria provided altogether 7,203 data-points, termed as ‘pooled-data’, which were stored in ms-excel. from those pooled-data, the dataset for ‘variety – transplanting time – seedling age – hill density’ were searched. the search resulted in 4491 meta-data points. those meta-data were used for meta-analysis. the year-wise pooled-data and meta-data are presented in table 1. table 1: year-wise number of pooled-data and meta-data gathered for meta-analysis year pooled-data (number) meta-data (number) 2010 515 245 2011 575 317 2012 824 609 2013 443 413 2014 618 170 2015 1034 746 2016 938 515 2017 763 516 2018 847 563 2019 646 397 total 7203 4491 meta-data categorization there varieties in screened data-points of 4491 were categorised into four groups such as aromatic (331 data-points), high yield potential or hyp (3870 data-point), market demand (47 data-points) and photosensitive (243 data-points). the study undertook detailed with hyp category considering the sample number of data-points. among the varieties existed in 3870 datapoints of hyp category, two top varieties (bbri dhan49, data-points 526 and swarna type, datapoints 163) were selected for detailed study. meta-data tabulation, processing and quality control all data were tabulated with unique identifier and curated. spacing converted to hill per m2 (hill density) and transplanting date converted to julian days. during the curation process, where data were not clearly recorded and/or had confusion on understanding, the respected sources were re-visited. after data extraction, an additional round of data editing and quality control of all studies was conducted. in order to analyse structurally, the meta-data were categorised for (i) variety diversification, (ii) transplanting time and (iii) seedling age and (iv) hill density. a meta-analysis of brri conducted ten years field research on transplanted aman rice 69 i. variety diversification: rice varieties were grouped into four categories in relation to product speciality. they were aromatic scented rice, high yield potential (fertilizer using efficiency is higher and has potentiality to give higher yield, hyp), market demand (high value rice varieties) that have demand in market for their taste at consumer level and photosensitivity (varieties which have photosensitivity to day length). ii. transplanting time: the whole range of the rice transplanting time applied in the metadata was categorised at 15-day interval into five groups very early (upto14 july, julian day 195), early (15 29 july, julian day 196 210), mid (30 july 13 august, julian day 211-225), late (14 28 august, julian day 226 240) and very late (after 28 august, julian day above 240). iii. seedling age: the whole range of the seedling age applied in the meta-data was categorised at 10-day interval into four groups, younger (≤ 30), middle (31-40), older (41-50), and very older > 50. iv. hill density (hill number per square meter): the whole range of the rice hill density explored in meta-data was categorised into three groups, standard (<= 30), high (<= 40), and very high (> 40). statistical analysis and presentation distribution of rice yields in meta-data was analyzed using ‘analysis tool pack of msexcel’ and presented as ‘box-whisker’ graph and ‘histogram’. variety and management specific yields were compiled using ‘pivot table’ function of ms-excel. yields were compared statistically using 95% confident interval. presentation of the results of meta-analysis followed the following sequence: (i) distribution of rice grain yield across all meta-data, to summarize overall yield scenarios, using ‘box-whisker’ graph. (ii) frequency distribution of the rice yields on a 1.0 t ha−1 interval across all meta-data, to summarize overall data scenarios, using ‘histogram’. (iii) relative percentage rice varieties accounted for in meta-data using ‘bar diagram’. (iv) relative percentage of rice variety group accounted for in meta-data according to purpose of growing ‘bar diagram’. (v) relative percentage of the variety and yield distribution of rice grain yield by variety group (defined as ‘purpose of growing’) accounted for in meta-data using ‘bar diagram’ and ‘boxwhisker’ graph, respectively. (vi) relative percentage of rice varieties under ‘hyp’ group accounted for in meta-data using ‘bar diagram’. (vii) grain yield distribution of rice varieties under ‘hyp’ group accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (viii) distribution of rice grain yield of brri dhan49 and swarna type accounted for in metadata ‘box-whisker’ graph. (ix) response of transplanting time across the varieties under ‘hyp’ group accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (x) response of transplanting time on of brri dhan49 and swarna type rice varieties accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (xi) response of seedling age across the varieties under ‘hyp’ group accounted for in metadata using ‘bar diagram’ and 95% confidence interval. (xii) response of seedling age on of brri dhan49 and swarna type rice varieties accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (xiii) response of hill density across the varieties under ‘hyp’ category accounted for in metadata using ‘bar diagram’ and 95% confidence interval. (xiv) response of hill density on of brri dhan49 and swarna type rice varieties accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. 70 parvin et al. (xv) spread of rice yield, year-by-year, across the varieties under ‘hyp’ group accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (xvi) spread of rice yield, location-by-location, across the varieties under ‘hyp’ group accounted for in meta-data using ‘bar diagram’ and 95% confidence interval. (xvii) spread of rice yield of the variety ‘brri dhan49’ across the environments designated in the meta-data sources and presented in a matrix of location (district) and season (year). this is a compilation of 526 data-points. number in a matrix represented the average of the yields for the matrix. the matrices were also represented by colored circles across the yield gradient: => 5 t ha−1(green), 4 to <5 t ha−1 (yellow), 3 to <4 t ha−1 (black) and <3 t ha−1 (red). (xviii) spread of rice yield of the variety ‘swarna type’ across the environments designated in the meta-data sources and presented in a matrix of location (district) and season (year). this is a compilation of 163 data-points. number in a matrix represented the average of the yields for the matrix. the matrices were also represented by coloured circles across the yield gradient: => 5 t ha−1 (green), 4 to <5 t ha−1 (yellow), 3 to <4 t ha−1 (black) and <3 t ha−1 (red). results and discussion distribution of rice grain yield the yields ranged from 0.03 to 7.76 t ha−1, where the middle 50% of the yield data concentrated within 3.50 to 5.04 t ha−1; the average yield was 4.22 t ha−1 and the median of yields was 4.30 t ha−1 (fig. 1). the average yield was 7.37 percent higher than national average of t. aman rice yield of bangladesh, 3.93 t ha−1 (equivalent clean rice yield of 2.63 t ha−1) as of 2019-20 data, brri, 2021b). fig. 1. distribution of rice grain yield in t. aman season recorded in 10 years research (2010 2019) accumulated in meta-data. box represents middle 50% of the yields, vertical line is the range, and within the box, horizontal line is the median and solid circle is the average frequency distribution of the rice yields in meta-data is presented in fig. 2. results indicate that, the yields were slightly skewed towards lower ends. the maximum frequency (35.3%) of the yields concentrated on 4.0 5.0 t ha−1, followed by 24.3 and 21.8% at 3.0 4.0 t ha−1 and 5.0 6.0 t ha−1, respectively. a small segment of experiments (0.9%) recorded comparatively low yield (0.0 1.0 t ha−1); on the other hand, 0.2% experiments achieved comparatively high yield (7.0 – 8.0 t ha−1). a meta-analysis of brri conducted ten years field research on transplanted aman rice 71 fig. 2. frequency distribution of rice grain yield in t. aman season recorded for 10 years research (2010 2019) accumulated in meta-data rice varieties accounted for in meta-data the meta-data recorded as many as 69 rice varieties (fig. 3). fig. 3. relative percentage of rice varieties accounted for in meta-data in 10 years research (2010 2019) during t. aman season 72 parvin et al. brri dhan49 was the most tested variety, which accounted for 11.7% of the data. this was closely followed by brri dhan39 (7.7%), br11 and brri dhan52 (6.3% each), brri dhan33 (4.3%), brri dhan51 (4.2%), brri dhan71 (3.7%), swarna type (3.6%), brri dhan54 (3.5%) and brri dhan56 (3.1%). about 3.5% of meta-data accounted for low yielding varieties. as indicated earlier, brri dhan49 used in large numbers in the research field. although not a variety of brri, swarna type rice varieties used in a significant amount of research area that indicates the importance of the variety at farm level. the popularity (farmer accounted for 60%) of swarna type variety was observed in another study (parvin et al., 2022). rice varieties accounted for in meta-data according to purpose of growing – relative percentage of rice variety group absolute majority of the meta-data (86.2%) included high yield potential (hyp) category, which comprised of 43 varieties (fig. 4). only small proportion of data belonged to ‘aromatic’ (7.4% data, 11 varieties), ‘photosensitivity’ (5.4% data, 11 varieties) and ‘market demand’ (1.0% data, 4 varieties) category. fig. 4. relative percentage of rice variety group (defined as ‘purpose of growing’) accounted for in meta-data in 10 years research (2010 2019) during t. aman season rice varieties accounted for in meta-data according to purpose of growing – the distribution of yields fig. 5 presents the distribution of rice yields recorded in meta-data under the four categories of purpose of growing. the highest average yield was achieved from the hyp group (4.34 t ha−1) followed by ‘market demand’ (3.88 t ha−1) and ‘photosensitivity’ (3.86 t ha−1) and the lowest in the varieties under ‘aromatic’ group (3.12 t ha−1). range of yield in the hyp varieties was 0.20 to 7.76 t ha−1 where the middle 50% of the yield data concentrated between 3.70 to 5.11 t ha−1. on the other hand, the range of yield of ‘market demand’ varieties were 2.11 to 5.91 t ha−1 where middle 50% of the yield data concentrated between 3.11 to 4.73 t ha−1. for the ‘photosensitivity’ group, the range of yield was 0.03 to 6.75 t ha−1, with the middle 50% of the yield data concentrated between 2.92 to 4.81 t ha−1. under the ‘aromatic’ rice group, where the average yield was the lowest, the meta-data recorded the yield in the range of 0.38 to 5.94 t ha−1 with the middle 50% of the yield between 2.66 to 3.72 t ha−1. a meta-analysis of brri conducted ten years field research on transplanted aman rice 73 fig. 5. distribution of rice grain yield by variety group (defined as ‘purpose of growing’) accounted for in meta-data in 10 years research (2010 2019) during t. aman season. box represents middle 50% of the yields, vertical line is the range, and within the box, horizontal line is the median and solid circle is the average. values inside the boxes denote for sample number within variety group. ‘hyp’ denotes for ‘high yield potential’ rice varieties accounted for in meta-data under ‘high yield potential (hyp)’ group relative percentage of the variety and yield distribution among the 43 varieties under the high yield potential (hyp)’ group, the meta-data accounted for 13.6% of brri dhan49, 8.9% of brri dhan39, 7.3% of br11 and brri dhan52, 5.0% of brri dhan33, 4.9% of brri dhan51, 4.3% of brri dhan71, 4.2% of swarna type and 4.0% of brri dhan54 (fig. 6). the rest 34 varieties, individually, accounted for < 4.0% in the composition of hyp group. fig. 6. relative percentage of rice varieties under ‘high yield potential (hyp)’ group y group accounted for in meta-data in 10 years research (2010 2019) during t. aman season the yield resulted from the varieties listed in the fig. 4, where it shows the newer varieties like brri dhan72, brri dhan79, brri dhan87, brri dhan76, brri dhan77, brri dhan78, brri dhan80, brri dhan90 produce higher yields (around 5 t ha−1). many varieties such as br 10, br 4, brri dhan49 and swarna type produce yield close to 4.5 t ha−1. 74 parvin et al. fig. 7. grain yield distribution of rice varieties under ‘high yield potential (hyp)’ group y group accounted for in meta-data in 10 years research (2010 2019) during t. aman season rice grain yield distribution of brri dhan49 and swarna type varieties accounted for in meta-data based on the farmers’ inclination of adoption of swarna type varieties (parvin et al., 2022), this section compares yields the top-ranked variety in meta-data, brri dhan49 with that of swarna type. it was observed that both the varieties recorded almost similar maximum yield (7.76 t ha−1 in brri dhan49 and 7.55 t ha−1 in swarna type). brri dhan49 produced the minimum yield of 0.38 t ha−1 and swarna type produced 0.44 t ha−1 (fig. 8). the fig. 8 further shows that the middle 50% yield data of brri dhan49 and swarna type was recorded between 4.09 to 5.36 t ha−1 and between 3.80 to 5.55 t ha−1, respectively. the average yield of 4.62 t ha−1 was found from brri dhan49 and 4.67 t ha−1 from swarna type. the median yield of 4.76 and 5.12 t ha−1 was received from brri dhan49 and swarna type, respectively. fig. 8. distribution of rice grain yield of brri dhan49 and swarna type accounted for in meta-data in 10 years research (2010 2019) during t. aman season. box represents middle 50% of the yields, vertical line is the range, and a meta-analysis of brri conducted ten years field research on transplanted aman rice 75 within the box, horizontal line is the median and solid circle is the average. values inside the boxes denote for sample number within variety group. management in rice varieties three management aspects transplanting time, seedling age, and hill density are presented below. transplanting time there was no significant trend in yield variation among the five-transplanting time (fig. 9). fig. 9. response of transplanting time across the varieties under high yield potential (hyp)’ group accounted for in metadata in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined transplanting time window. for brri dhan49, the average yield trend shows an increase from very early transplanting time to early transplanting time, then slowly decrease till the latest transplanting time. however, yields under the five transplanting time did not vary significantly (fig. 10). for swarna type, the average yield trend shows gradual decrease from early to late transplanting time, then slightly increased in very late transplanting time. the yield from late transplanting time (4.11 t ha−1) was significantly lower than early (4.99 t ha−1) or mid (4.89 t ha−1) transplanting time, but not from the very late (4.30 t ha−1). it may be noted that data for very early transplanting time was not available for this variety. 76 parvin et al. fig. 10. response of transplanting time on of brri dhan49 and swarna type rice varieties accounted for in meta-data in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined transplanting time window seedling age younger, middle aged and older seedlings produced statistically similar yield (fig. 11). fig. 11. response of seedling age across the varieties under high yield potential (hyp)’ group accounted for in meta-data in 10 years’ research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined seedling age group in brri dhan49, yield was the highest in older aged seedling (sa) group (5.13 t ha−1), significantly higher than middle (4.48 t ha−1) but not with younger sa group (4.64 t ha−1) (fig. 4.24). for swarna type, the yield trend for sa groups was similar to brri dhan49. across the sa groups under swarna type, the yield differences were not significant (fig. 12). a meta-analysis of brri conducted ten years field research on transplanted aman rice 77 fig. 12. response of seedling age on of brri dhan49 and swarna type rice varieties accounted for in metadata in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined seedling age group hill density the very high hill density produced significantly higher yield than standard or high hill density (fig. 13); difference of mean yield between standard and high hill density was not significant. fig. 13. response of hill density across the varieties under high yield potential (hyp)’ group accounted for in meta-data in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined hill density group. the yield in both varieties increased with increase in hill density (standard, high and very high) (fig. 14). the yield differences in brri dhan49 due to hill density were not significant. on the other hand, in swarna type the yield in very high hill density was significantly higher than high or standard hill density, with no statistical difference between high or standard hill densities. 78 parvin et al. fig. 14. response of hill density on of brri dhan49 and swarna type rice varieties accounted for in meta-data in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined hill density group. environmental response of rice varieties the meta-analysis showed average yield varies between years of experimentations, for example fig. 15. yield in 2017 was significantly lower and yield in 2018 was significantly higher compared to other years. yield also varied between the locations, for example yield was significantly high in dinajpur, jamalpur, jhalokathi, habiganj, kushtia and thakurgaon compared to low yield in joypurhat, bogura. (fig. 16). fig. 15. spread of rice yield, year-by-year, across the varieties under high yield potential (hyp)’ group accounted for in meta-data in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined year a meta-analysis of brri conducted ten years field research on transplanted aman rice 79 fig. 16. spread of rice yield, location-by-location, across the varieties under high yield potential (hyp)’ group accounted for in meta-data in 10 years research (2010 2019) during t. aman season. vertical bars represent 95% confidence intervals of the meta-data yields within each defined location. for brri dhan49, the high (=> 5 t ha−1) and second high (4 to < 5 t ha−1) yields spread across the locations (designated as districts) and years (fig. 17). the presence of moderate yields (3 to < 4 t ha−1) was dominantly observed across the years in two locations rangpur and cumilla, whereas low yields (< 3 t ha−1) were recorded only during 2015 in lalmonirhat, nilphamari and sylhet. the 2015 was the year when the yield variability observed across the four yield gradients, depending on locations. fig. 17. spread of rice yield of the variety ‘brri dhan49’ across the environments (matrix of location (district) and season (year) designated in the meta-data sources. this is a compilation of 526 data-points. number within a cell in the figure denotes for average of a yield for the matrix. the filled circles represent yield gradient as expressed in the legend. 80 parvin et al. for swarna type, the high (=> 5 t ha−1) yields spread across locations during 2013 to 2017 (no data were available for 2014) (fig. 18). the presence of the second high (4 to < 5 t ha−1) yields was very limited, whereas the moderate yields (3 to < 4 t ha−1) were recorded across wider locations and years. on the other hand, low yields (< 3 t ha−1) were reported in three scenarios kushtia in 2011, rajshahi in 2012 and rangpur in 2019. fig. 18. spread of rice yield of the variety ‘swarna type’ across the environments (matrix of location (district) and season (year) designated in the meta-data sources. this is a compilation of 163 data-points. number within a cell in the figure denotes for average of a yield for the matrix. the filled circles represent yield gradient as expressed in the legend. conclusion the meta-analysis shows the yield potential is not solely dependent on varietal category, environmental adaptation and optimized management practices are also crucial. the results provide a clear message to stakeholders that variety-environment-management synchronized approach is essential for improved yields of t. aman rice in bangladesh. references anderson, w.k. 2009. closing the gap between actual and potential yield of rainfed wheat. the impacts of environment, management and cultivar. field crop res. 116: 14-22. brri 2012a: brri annual report 2009-2010. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.211. brri 2012b: brri annual report 2009-2010. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.327. a meta-analysis of brri conducted ten years field research on transplanted aman rice 81 brri 2013: brri annual report 2010-2011. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.262. brri 2013a: brri annual report 2010-2011. rice farming systems division. page: 159, table: 27. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013b: brri annual report 2010-2011. rice farming systems division. page: 162, table: 30. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013c: brri annual report 2010-2011. rice farming systems division. page: 164, table: 34. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013d: brri annual report 2010-2011. brri regional station, cumilla. page: 262, table: 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013e: brri annual report 2010-2011. brri regional station, kushtia. page: 278, table: 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013f: brri annual report 2010-2011. brri regional station, rajshahi. page: 285, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013g: brri annual report 2010-2011. brri regional station, rajshahi. page: 286, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013h: brri annual report 2010-2011. brri regional station, rajshahi. page: 287, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013i: brri annual report 2010-2011. brri regional station, rajshahi. page: 288, table: 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013j: brri annual report 2010-2011. brri regional station, rajshahi. page: 289, table: 8. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013k: brri annual report 2010-2011. brri regional station, rajshahi. page: 291, table: 10. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013l: brri annual report 2010-2011. brri regional station, rajshahi. page: 293, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013m: brri annual report 2010-2011. brri regional station, rajshahi. page: 293, table: 13. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2013n: brri annual report 2010-2011. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.262. brri 2014a: brri annual report 2011-2012. plant breeding division. page: 6, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014b: brri annual report 2011-2012. agronomy division. page: 67, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014c: brri annual report 2011-2012. rice farming systems division. page: 179, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014d: brri annual report 2011-2012. agricultural economics division. page: 186, table: 22. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014e: brri annual report 2011-2012. brri regional station, cumilla. page: 274, table: 1, 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014f: brri annual report 2011-2012. brri regional station, cumilla. page: 275, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014g: brri annual report 2011-2012. brri regional station, cumilla. page: 276, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014h: brri annual report 2011-2012. brri regional station, cumilla. page: 280, table: 12. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014i: brri annual report 2011-2012. brri regional station, kushtia. page: 291, table: 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014j: brri annual report 2011-2012. brri regional station, kushtia. page: 294, table: 9. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014k: brri annual report 2011-2012. brri regional station, kushtia. page: 295, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014l: brri annual report 2011-2012. brri regional station, kushtia. page: 297, table: 14. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. 82 parvin et al. brri 2014m: brri annual research review workshop [2011-2012], plant breeding division. table: 6.13, 6.14a-c, 6.15c, 6.15d, 14.16-14.18, 14.24, 15.3-15.6, 15.9, 22.7-22.9. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014n: brri annual research review workshop [2011-2012], brri regional station, rangpur. table: 22, 34, 37, 39. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014o: brri annual research review workshop [2011-2012], brri regional station, rajshahi. table: 2-4, 7, 11, 19. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 334. brri 2014p: brri annual report 2012-2013. agronomy division. page: 72, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014q: brri annual report 2012-2013. agronomy division. page: 73, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014r: brri annual report 2012-2013. agronomy division. page: 75, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014s: brri annual report 2012-2013. agronomy division. page: 81, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014t: brri annual report 2012-2013. irrigation and water management division. page: 99, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014u: brri annual report 2012-2013. rice farming systems division. page: 185, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014v: brri annual report 2012-2013. rice farming systems division. page: 190, table: 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014w: brri annual report 2012-2013. rice farming systems division. page: 193, table: 8, 9. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014x: brri annual report 2012-2013. brri regional station, cumilla. page: 292, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014y: brri annual report 2012-2013. brri regional station, cumilla. page: 293, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014z: brri annual report 2012-2013. brri regional station, cumilla. page: 294, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014aa: brri annual report 2012-2013. brri regional station, cumilla. page: 299, table: 9, 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ab: brri annual report 2012-2013. brri regional station, kushtia. page: 310, table: 2, 3, 4, 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ac: brri annual report 2012-2013. brri regional station, kushtia. page: 311, table: 6, 7, 8. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ad: brri annual report 2012-2013. brri regional station, kushtia. page: 315, table: 17. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ae: brri annual report 2012-2013. brri regional station, kushtia. page: 316, table: 18. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014af: brri annual report 2012-2013. brri regional station, kushtia. page: 317, table: 19. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ag: brri annual report 2012-2013. brri regional station, rajshahi. page: 326, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ah: brri annual report 2012-2013. brri regional station, rajshahi. page: 327, table: 6, 7, 8, 9, 10. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ai: brri annual report 2012-2013. brri regional station, rajshahi. page: 328, table: 12, 13. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014aj: brri annual report 2012-2013. brri regional station, rajshahi. page: 329, table: 12, 13. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ak: brri annual report 2012-2013. brri regional station, rajshahi. page: 330, table: 15, 16. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014al: brri annual report 2012-2013. brri regional station, rajshahi. page: 331, table: 17. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. a meta-analysis of brri conducted ten years field research on transplanted aman rice 83 brri 2014am: brri annual report 2012-2013. brri regional station, rangpur. page: 340, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014an: brri annual report 2012-2013. brri regional station, rangpur. page: 342, table: 7, 8, 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 360. brri 2014ao: brri annual research review workshop 2012-2013, brri regional station, sonagazi. table: 8-11. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014ap: brri annual research review workshop 2012-2013, brri regional station, rangpur. table: 10, 11, 22. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014aq: brri annual research review workshop 2012-2013, brri regional station, habiganj. table: 21. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014ar: brri annual research review workshop 2012-2013, brri regional station, rajshahi. table: 2, 3, 7, 26-28, 30, 48. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014as: brri annual research review workshop 2012-2013, brri regional station, kushtia. table: 2-7, 9, 18, 19. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014at: brri annual research review workshop 2012-2013, brri regional station, barisal. table: 8, 17, 21. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014au: brri annual research review workshop 2012-2013, plant breeding division. table: 3.53.9, 4.1, 4.6-4.10, 4.16, 4.17, 6.10-6.12, 6.13a, 6.13b, 9.6, 10.4, 18.7, 18.8a, 18.9, 23a.5ab, 23a.6a-c, 23a.7, 23a.8. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2014av: brri annual report 2012-2013. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 317. brri 2015a: brri annual report 2013-2014. hybrid rice division. page: 47, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015b: brri annual report 2013-2014. hybrid rice division. page: 48, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015c: brri annual report 2013-2014. agronomy division. page: 54, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015d: brri annual report 2013-2014. irrigation and water management division. page: 89, table: 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015e: brri annual report 2013-2014. irrigation and water management division. page: 90, table: 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015f: brri annual report 2013-2014. rice farming systems division. page: 147, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015g: brri annual report 2013-2014. rice farming systems division. page: 150, table: 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015h: brri annual report 2013-2014. adaptive research division. page: 153, table: 11, 12. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015i: brri annual report 2013-2014. adaptive research division. page: 222, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015j: brri annual report 2013-2014. adaptive research division. page: 223, table: 4, 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015k: brri annual report 2013-2014. adaptive research division. page: 224, table: 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015l: brri annual report 2013-2014. brri regional station, rangpur. page: 287, table: 6, 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015m: brri annual report 2013-2014. brri regional station, rangpur. page: 288, table: 10. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015n: brri annual report 2013-2014. brri regional station, rangpur. page: 289, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015o: brri annual report 2013-2014. brri regional station, rangpur. page: 290, table: 13, 15. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015p: brri annual report 2013-2014. brri regional station, kushtia. page: 314, table: 9. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 320. brri 2015q: brri annual research review workshop 2013-2014, brri regional station, rajshahi. table: 7-11, 18, 20, 27-29. bangladesh rice research institute (brri), gazipur 1701, bangladesh. 84 parvin et al. brri 2015r: brri annual research review workshop 2013-2014, brri regional station, rangpur. table: 19, 20, 31, 35a. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2015s: brri annual research review workshop 2013-2014, brri regional station, sonagazi. table: 4-6. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2015t: brri annual research review workshop 2013-2014, brri regional station, kushtia. table: 2, 3, 8, 9, 18, 22, 25. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2015u: brri annual research review workshop 2013-2014, plant breeding division. table: 4.54.10, 7.6, 7.7, 7.11, 13a.5-8, 14.5-14.11, 14.13a, 14.17, 14.18, 18.a1, 18.a2.1-3, 18.a.3, 18.a.5. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016a: brri annual report 2014-2015. hybrid rice division. page: 46, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016b: brri annual report 2014-2015. hybrid rice division. page: 47, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016c: brri annual report 2014-2015. agronomy division. page: 54, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016d: brri annual report 2014-2015. agronomy division. page: 126, table: 1, 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016e: brri annual report 2014-2015. brri regional station, cumilla. page: 224, table: 2, 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016f: brri annual report 2014-2015. brri regional station, habiganj. page: 228, table: 3, 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016g: brri annual report 2014-2015. brri regional station, rangpur. page: 241, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016h: brri annual report 2014-2015. brri regional station, satkhira. page: 257, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016i: brri annual report 2014-2015. brri regional station, satkhira. page: 258, table: 3-5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016j: brri annual report 2014-2015. brri regional station, satkhira. page: 259, table: 6, 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016k: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 260, table: 8-10. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016l: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 261, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016m: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 262, table: 12. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016n: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 263, table: 13-15. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016o: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 264, table: 16-18. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016p: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 265, table: 19, 20. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016q: brri annual report 2014-2015. brri regional station, brri regional station, satkhira. page: 266, table: 21. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016r: brri annual report 2014-2015. brri regional station, kushtia. page: 275, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016s: brri annual report 2014-2015. brri regional station, kushtia. page: 276, table: 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016t: brri annual report 2014-2015. brri regional station, kushtia. page: 277, table: 7, 8. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. a meta-analysis of brri conducted ten years field research on transplanted aman rice 85 brri 2016u: brri annual report 2014-2015. brri regional station, kushtia. page: 278, table: 9-11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 278. brri 2016v: brri annual research review workshop 2014-2015, plant breeding division. table: 6-7.8, 7.12, 13.7, 13.8, 14.5-14.8, 14.9a, 14.10a, 14.12a, 15.5a-d. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016w: brri annual report 2015-2016. plant breeding division. page: 3. table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016x: brri annual research review workshop 2015-2016, plant breeding division. table: 3.5, 13.5-13.8, 14.6-14.13, 14.16-14.18, 16.7-16.10. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016y: brri annual report 2015-2016. hybrid rice division. page: 47, table: 2, 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016z: brri annual report 2015-2016. agronomy division. page: 53, table: 2a, 3a. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016aa: brri annual report 2015-2016. adaptive research division. page: 187, table: 1, 2, 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ab: brri annual report 2015-2016. adaptive research division. page: 188, table: 4, 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ac: brri annual report 2015-2016. adaptive research division. page: 189, table: 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ad: brri annual report 2015-2016. brri regional station, bhanga. page: 215, table: 3, 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ae: brri annual report 2015-2016. brri regional station, cumilla. page: 221, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016af: brri annual report 2015-2016. brri regional station, habiganj. page: 232, table: 8. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ag: brri annual report 2015-2016. brri regional station, rajshahi. page: 238, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ah: brri annual report 2015-2016. brri regional station, rangpur. page: 244, table: 1, 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ai: brri annual report 2015-2016. brri regional station, rangpur. page: 245, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016aj: brri annual report 2015-2016. brri regional station, rangpur. page: 248, table: 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ak: brri annual report 2015-2016. brri regional station, rangpur. page: 249, table: 8. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016al: brri annual report 2015-2016. brri regional station, satkhira. page: 254, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016am: brri annual report 2015-2016. brri regional station, satkhira. page: 256, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016an: brri annual report 2015-2016. brri regional station, kushtia. page: 271, table: 4, 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 274. brri 2016ao: brri annual research review workshop 2015-2016, brri regional station, barisal. table: 40a-d. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016ap: brri annual research review workshop 2015-2016, brri regional station, sonagazi. table: 3-10, 18-22. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016aq: brri annual research review workshop 2015-2016, brri regional station, satkhira. table: 21, 35-47. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016ar: brri annual research review workshop 2015-2016, brri regional station, rangpur. table: 2, 4, 6-9, 30. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016as: brri annual research review workshop 2015-2016, brri regional station, rajshahi. table: 6, 15, 17-20, 22, 23, 26-30. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016at: brri annual research review workshop 2015-2016, brri regional station, habiganj. table: 4-10. bangladesh rice research institute (brri), gazipur 1701, bangladesh. 86 parvin et al. brri 2016au: brri annual research review workshop 2015-2016, brri regional station, bhanga. table: 16. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2016av: brri annual research review workshop 2015-2016, brri regional station, cumilla. table: 10-19, 55. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017a: adhunik dhaner chash (modern rice cultivation), 20th edition. bangladesh agricultural research institute, gazipur-1701. brri 2017b: brri annual report 2016-2017. hybrid rice division. page: 51, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017c: brri annual report 2016-2017. hybrid rice division. page: 52, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017d: brri annual report 2016-2017. agronomy division. page: 62, table: 3-5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017e: brri annual report 2016-2017. agronomy division. page: 66, table: 11. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017f: brri annual report 2016-2017. agronomy division. page: 67. table: 12, 14. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017g: brri annual report 2016-2017. rice farming systems division. page: 157, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017h: brri annual report 2016-2017. brri regional station, habiganj. page: 280, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 335. brri 2017i: brri annual report 2016-2017. plant breeding division. table: 3.5, 3.6, 12.8.1a, 13.5a, 13.6a, 13.7, 14.6-14.8, 14.11-14.13, 14.15.2, 14.16. brri 2017j: brri annual research review workshop 2016-2017, plant breeding division. table: 1-3. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017k: brri annual research review workshop 2016-2017, brri regional station, kushtia. table: 4, 9-14, 16, 25, 32. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017l: brri annual research review workshop 2016-2017, brri regional station, rangpur. table: 2, 27-31, 33, 34, 36-40. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017m: brri annual research review workshop 2016-2017, brri regional station, cumilla. table: 11-16, 21, 56, 65-70. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017n: brri annual research review workshop 2016-2017, brri regional station, satkhira. table: 1-13, 25, 36-39, 42, 48-53, 55-60. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017o: brri annual research review workshop 2016-2017, brri regional station, barisal. table: 36. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2017p: brri annual research review workshop 2016-2017, brri regional station, bhanga, faridpur. table: 7-8. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2018a: brri annual report 2017-2018. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 331 brri 2018b: brri annual report 2017-2018. agronomy division. page: 70, table: 5, 6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018c: brri annual report 2017-2018. brri regional station, bhanga. page: 257, table: 5. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018d: brri annual report 2017-2018. brri regional station, cumilla. page: 266, table: 3. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018e: brri annual report 2017-2018. brri regional station, cumilla. page: 269, table: 7. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018f: brri annual report 2017-2018. brri regional station, cumilla. page: 270, table: 12. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018g: brri annual report 2017-2018. brri regional station, rajshahi. page: 286, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018h: brri annual report 2017-2018. brri regional station, satkhira. page: 303, table: 1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018i: brri annual report 2017-2018. brri regional station, satkhira. page: 305, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. a meta-analysis of brri conducted ten years field research on transplanted aman rice 87 brri 2018j: brri annual report 2017-2018. brri regional station, kushtia. page: 331, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018k: brri annual report 2017-2018. brri regional station, habiganj. table: 4-6. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018l: brri annual report 2017-2018. brri regional station, kushtia. table: 6-17. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018m: brri annual report 2017-2018. brri regional station, satkhira. table: 1-11, 28, 30, 39, 40, 42-48, 55-58, 76, 77, 78. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018n: brri annual report 2017-2018. brri regional station, agronomy. table: 6, 7.3, 10.3, 11.3, 26, 35, 46. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018o: brri annual report 2017-2018. brri regional station, barisal. table: 33a-c. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018p: brri annual report 2017-2018. brri regional station, soil science division. table: 13, 15. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018q: brri annual report 2017-2018. brri regional station, cumilla. table: 11, 13, 14, 39, 44, 57, 58, 59, 60a, 60b. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018r: brri annual report 2017-2018. brri regional station, rajshahi. table: 5, 7-12, 14, 1626, 42. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018s: brri annual report 2017-2018. brri regional station, rangpur. table: 32, 14, 16-26, 42. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018t: brri annual report 2017-2018, bangladesh rice research institute (brri), gazipur 1701, bangladesh, p.332. brri 2018u: brri annual report 2017-2018. brri regional station, kushtia. table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2018v: brri annual report 2017-2018. agronomy division. page: 72, table: 10. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 332. brri 2019a: brri annual research review workshop 2019-2020, brri regional station, rangpur. table: 13, 19-28. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019b: brri annual research review workshop 2019-2020, brri regional station, bhanga. table: 21-23. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019c: brri annual research review workshop 2019-2020, brri regional station, habiganj. table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019d: brri annual research review workshop 2019-2020, brri regional station, kushtia. table: 2-17, 28. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019e: brri annual research review workshop 2019-2020, brri regional station, cumilla. table: 8-10, 38, 40, 42, 43c, 59-62. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019f: brri annual research review workshop 2019-2020, rice farming systems divisions. table: 5, 7, 9, 34. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019g: brri annual research review workshop 2019-2020, regional station, rajshahi. table: 524, 27-37, 63, 74, 76. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019h: brri annual research review workshop 2019-2020, regional station, satkhira. table: 113, 23, 28, 31-35, 37-40, 42-51, 53-60. bangladesh rice research institute (brri), gazipur 1701, bangladesh. brri 2019i: brri annual report 2019-2020. brri regional station, cumilla. page: 304, table: 2. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019j: brri annual report 2019-2020. brri regional station, habiganj. page: 313, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019k: brri annual report 2019-2020. brri regional station, rangpur. page: 335, table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019l: brri annual report 2019-2020. regional station, rangpur. table: 10, 17-22, 25. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019m: brri annual report 2019-2020. regional station, habiganj. table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. 88 parvin et al. brri 2019n: brri annual report 2019-2020. regional station, satkhira. table: 1-7, 14, 15, 19-21, 28, 36, 37, 43-55, 50a-c, 54a-c, 56-59. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019o: brri annual report 2019-2020. plant breeding division. table: 3.4, 4.4, 4.5, 4.6, 4.7, 6.6.1-6.6.6, 7a.5, 7.6.1, 7.6.2, 7a.7.1-7a.7.3, 7.8, 11.5.1, 13.6.1, 14.1, 14.2, 14.9, 14.14.1. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019p: brri annual report 2019-2020. regional station, kushtia. table: 24. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019q: brri annual report 2019-2020. regional station, rangpur. table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2019r: brri annual report 2019-2020. regional station, rangpur. table: 4. bangladesh rice research institute (brri), gazipur 1701, bangladesh, p. 376. brri 2020a: annual research review xv agricultural economics division. annual research review workshop 2019-20. bangladesh rice research institute (brri), gazipur 1701, bangladesh. p.3. brri 2020b: bangladesh rice research institute, adhunik dhaner chash (modern rice cultivation), 23 th edited. gazipur 1701, bangladesh (in bangla). brri 2020c: annual research review xv agricultural economics division. annual research review workshop 2019-20. bangladesh rice research brri 2021: brri annual report 2020-2021, bangladesh rice research institute (brri), gazipur 1701, bangladesh. p. 234. brri 2021a: cropping pattern, intensity and diversity in dhaka region. bangladesh rice journal 21(2) 1155. table of content, appendix 06. brri 2021b: bangladesher dhaner jomi, uthpdan o pholoner data (rice area, production and yield in bangladesh). rice database. brri 2021c: brri annual report 2020-2021, bangladesh rice research institute (brri), gazipur 1701, bangladesh. p. 234. cho, h., h. kim, d. na, s.y. kim, d. jo and d. lee. 2016. meta-analysis method for discovering reliable biomarkers by integrating statistical and biological approaches: an application to liver toxicity. biochem. biophys. res. commun. 471: 274–281. garg, a.x., d. hackam and m. tonelli. 2008. systematic review and meta-analysis: when one study is just not enough. clin. j. am. soc. nephrol. 3: 253–260. hillebrand, h. and b.j. cardinale. 2010. a critique for meta-analyses and the productivity-diversity relationship. ecology. 91(9): 2545–2549. higgins, j.p.t. and s.g. thompson. 2002. quantifying heterogeneity in a meta-analysis. stat. med. 21: 1539–1558. hernandez, a.v., k.m. marti and y.m. roman. 2020. meta-analysis. 158: s97–s102. parvin, n., m.a. salam, m.u. salam, m.a. kader and nessa, b. 2022. farmers’ rice yield in fallow t. aman rice fallow cropping pattern due to variability in genotype and management, bangladesh agron. j. 25(1): 23-36. sarwar, a. k. m. g. and j. k. biswas. 2021. cereal grains of bangladeshpresent status, constraints and prospects, cereal grains, 6th april, 2021 sayeed, k.a. and m.m. yunus. 2018. rice prices and growth, and poverty reduction in bangladesh. food and agriculture organization of the united nations, rome. pp 45. blank page bangladesh agron. j. 2022, 25(2): 89-96 performance of aman rice varieties under different nutrient management a. mushtaree, m.a.r. sarkar, m.s. kabiraj, s.k. sarkar, m.h. rashid and s.k. paul department of agronomy, bangladesh agricultural university, mymensingh -2202, bangladesh corresponding e-mail: skpaul@bau.edu.bd (received: 21 november 2022, accepted: 23 january 2023) keywords: nutrient, aman rice, grain yield abstract an experiment was conducted at the agronomy field laboratory, bangladesh agricultural university, mymensingh during july to december 2017 to investigate the combined effect of poultry manure with inorganic fertilizers on the yield of bina developed transplant aman rice varieties. the experiment comprised three varieties viz. binadhan-15, binadhan-16 and binadhan-17 with five nutrient management viz. control (no application of manures and fertilizers), 100% recommended dose of inorganic fertilizer (urea-tsp-mop-gypsum-zinc sulphate @ 150-110-70-60-5 kg ha-1) (rf), poultry manure @ 5 t ha-1, 75% rf + poultry manure @ 5 t ha-1, 50% rf + poultry manure @ 5 t ha-1. the experiment was laid out in a randomized complete block design with three replications. number of total tillers hill-1 (13.37), number of effective tillers hill-1 (6.76), grains panicle-1 (107.86 cm), grain yield (6.97 t ha-1), straw yield (8.36 t ha-1), and harvest index (45.47%) were found to be the highest in binadhan-17 and the highest weight of 1000-grain (27.32 g) was recorded in binadhan-16. among the nutrient management, 75% rf + poultry manure @ 5 t ha-1 exhibited its superiority to other treatments in terms of number of total tillers hill-1(11.74), grains panicle-1 (115.26), 1000-grain weight (23.49 g), grain yield (6.57 t ha-1) and harvest index (48.20%). the highest grain yield (7.10 t ha-1) was found in binadhan-17 with 75% rf + poultry manure @ 5 t ha-1 and the lowest grain yield (5.32 t ha-1) was found in binadhan-16 with control treatment. from the study, it can be concluded that binadhan-17 fertilized with 75% recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1 appears as the promising practice to obtain the highest grain yield. introduction agriculture is the mainstay of the economy in terms of gdp as well as the improvement of livelihood of the majority people in bangladesh. rice (oryza sativa l.) is the staple food and has been being grown in this country from time immemorial. the production of milled rice reached around 38.78 million tons and it contributes to about 92% of the total food grains produced in the country (bbs, 2020). rice is cultivated in 75.03% of our agricultural land (bbs, 2020) but the average yield of rice in bangladesh is lower (3.04 t ha-1) than the highest rice-producing country china with 12.9 t ha-1 rice yield (sinha et al., 2018). there are three rice-growing seasons in bangladesh viz. aus, aman, and boro. among them, transplant aman rice contributed the most to the total yield and it covers the second largest area of 56 lac hectares with a production of 131 lac tons of rice (bbs, 2020). in rice production, suitable variety selection is very important because, the higher yield depends mostly on the varietal performance. 90 mushtaree et al. bangladesh has a bright prospect for higher rice production but due to the lack of improved variety, judicious use of fertilizers, and different management practices could be responsible for the lower yield. the productivity of crops decreases due to nutrient mining, soil organic matter depletion, and reduction of soil aggregates (rahman and yakupitiyage, 2006). excess fertilizer application influences nutrient loss, surface water and groundwater contamination, soil acidification or basification, reduction in useful microbial communities, and increased sensitivity to harmful insects. there are evidences that organic manures enhanced rice production and increased the yield and quality of agricultural produce with maintaining soil health more fertile (nayak et al., 2020). although compared to inorganic fertilizers, organic manures have some shortcomings such as supplying low nutrient content in a short time, slow decomposition etc. therefore, a suitable approach to nutrient management is required to keep the production of rice to a notable amount and increase the nutrient use efficiency of soil (paul et al., 2021). the combined application of organic manures and inorganic fertilizers in rice fields provides favorable soil physical conditions with favorable microbial activity and nutrient availability (gill and walia, 2014). coupled application of chemical fertilizer with manure can curtail doses of the chemical fertilizers increasing grain yield of rice (sarkar et al., 2014; pal et al., 2016; adhikari et al., 2018; paul et al., 2019; paul et al., 2020). the present study was undertaken to evaluate the yield-ability of three newly released aman rice varieties under various nutrient management practices integrating organic manure with the chemical fertilizer application. materials and methods the investigation was carried out at the agronomy field laboratory, bangladesh agricultural university, mymensingh during july to december 2017. the experimental site is located at 24.75°n latitude and 90.50°e longitude at an altitude of 18 m. the site belongs to the noncalcareous dark grey floodplain soil under the agro-ecological zone of the old brahmaputra floodplain (aez-9). the experiment comprised three varieties viz. binadhan-15, binadhan-16 and binadhan-17 with five nutrient management viz. control (no application of manures and fertilizer), 100% recommended dose of inorganic fertilizer (urea-tsp-mop-gypsum-zinc sulphate @ 150-110-70-60-5 kg ha-1) (rf), poultry manure @ 5 t ha-1, 75% rf + poultry manure @ 5 t ha-1, 50% rf + poultry manure @ 5 t ha-1. the method of the experiment was a randomized complete block design (rcbd) with three replications. the size of the unit plot was 10 m2 (4.0 x 2.5 m). seeds of rice varieties of binadhan-15, binadhan-16 and binadhan-17 were collected from bangladesh institute of nuclear agriculture (bina). seeds were soaked in water for 24 hours and stored in gunny bags. the seeds started sprouting after 72 hours and were ready for sowing. the sprouted seeds were sown in the nursery bed on 12 july 2017. the field was prepared by power tiller with three times ploughing and cross ploughing followed by laddering. the layout of the field was made on august 16, 2017 according to the experimental specification immediately after final land preparation. weeds and stubble were removed and cleaned from individual plots. the land was fertilized as per treatment specifications. at the time of final land preparation, respective unit plots were fertilized with different levels of fertilizers according to treatments. the poultry manure was thoroughly mixed with the soil. triple super phosphate, muriate of potash, gypsum and zinc sulphate was applied at final land preparation as per treatment. urea was applied at three equal instalments at 15, 30 and 45 days after transplanting (dat). thirty-fiveperformance of aman rice varieties under different nutrient management 91 day old seedlings were carefully uprooted from the nursery bed and transplanted in the wellpuddled field on 17 august 2017 at the rate of three seedlings hill-1 maintaining 25 cm x 15 cm spacing. to ensure normal growth intercultural operations were done timely. the plots were kept weed free up to 40 dat by hand pulling as and when needed but afterward no weeding was done. the bunds around the individual plots were repaired as and when necessary, so that water along with nutrient elements did not move between plots. at harvest, five hills (excluding border hills) were selected randomly from each unit plot excluding border rows and central 2.0 m × 2.5 m harvest area and uprooted to record data on crop characters and yield components. after sampling, central 2.0 m × 2.5 m area was harvested. harvesting of three varieties was done at different dates. harvesting of binadhan-15, binadhan16 and binadhan-17 were done on 21 november, 24 november and 17 november 2017, respectively. the harvested crop was threshed separately and the threshing was done manually. the cleaned grains were dried at 14% moisture. straws were also dried properly. finally grain and straw yields were converted to t ha-1. analysis of variance (anova) was done to investigate the significant differences in the recorded parameters resulting from experimental treatments. mean differences were adjudged by duncan's multiple range test (dmrt) following gomez and gomez (1984). statistical analyses were performed using the software package mstat-c. result and discussion the imposed treatment variety had significant effects on crop characters, yield and yield components of transplant aman rice. the plant height (98.83 cm), number of total tillers hill-1 (13.37), number of effective tillers hill-1 (6.76), number of grains panicle-1 (107.86), and harvest index (45.47%) were recorded highest in binadhan-17 (table 1). binadhan-17 produced the highest grain (6.97 t ha-1) and straw (8.36 t ha-1) yields followed by binadhan-16 (figure 1). however, binadhan-15 showed lowest values of these parameters. fig. 1. effect of variety on grain and straw yield of t. aman rice due to varietal characters plant height, number of total tillers hill-1, number of grains panicle-1, grain yield, straw yield and harvest index influenced significantly. effect of variety on total number of tillers hill-1 was also reported by sarkar et al. (2014) who observed that total number of tillers hill-1 differed among the varieties which might be due to varietal character or heredity. sarkar et al. (2014) found varietal differences of aromatic fine rice in respect of straw yield. 92 mushtaree et al. number of effective tillers hill-1 and number of sterile spikelets panicle-1 were not significantly influenced in respect of different varieties. numerically, the highest number of effective tillers hill1 (3.70), the longest panicle (21.53 cm) and the highest number of sterile spikelets panicle-1 (14.82) were produced by binadhan-15, while the lowest results were observed by binadhan117. islam et al. (2014) found variation these parameters based on variety and reported that the reason of difference is the genetic makeup of the variety, which is primarily influenced by heredity. weight of 1000-grain was significantly affected by variety. the highest weight of 1000-grain (27.32 g) was recorded in binadhan-16 followed by binadhan-17 and the lowest 1000-grain weight (21.01 g) was found in binadhan-15 (table 1). weight of 1000-grain varied due to variety was reported elsewhere (bhowmik et al., 2011; sarkar et al., 2014; ray et al., 2015; adhikari et al., 2018). table 1. effect of variety on crop characters and yield components of transplant aman rice variety plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) length of panicle (cm) sterile spikelets panicle-1 (no.) grains panicle-1 (no.) 1000 grain weight (g) harvest index (%) binadhan15 93.35b 10.08b 6.08 3.70a 21.53a 14.82 102.32b 21.01c 43.82ac binadhan16 95.85ab 10.35b 6.36 1.96b 20.69bc 13.09 102.46b 27.32a 44.12b binadhan17 98.83a 13.37a 6.76 1.44c 20.48c 11.34 107.86a 23.63b 45.47a level of sig. * * ns * * ns * ** ** cv (%) 4.73 3.26 5.13 9.39 4.27 7.17 3.68 5.14 4.56 in a column, mean values with the same letter (s) or without letter do not differ significantly whereas mean values with dissimilar letter differ significantly (as per dmrt). ** = significant at 1% level of probability, * = significant at 5% level of probability, ns = not significant nutrient management played important role on crop characters, yield and yield components transplant aman rice (table 2 and figure 2). application of 75% rf + poultry manure @ 5 t ha-1 resulted in the highest plant height (96.50 cm), the highest number of total tillers hill-1 (11.74), the highest number of grains panicle-1 (115.26), the heaviest 1000-grain (23.49 g), the highest grain yield (6.57 t ha-1) and the highest harvest index (48.20%) while the shortest plant (93.90 cm), the lowest values of total tillers hill-1 (9.24), grains panicle-1 (107.6), 1000-grain weight (21.78 g) and grain yield (5.66 t ha-1), were found in control treatment (table 2 & figure 2). in the previous reports, such combined application of organic and inorganic fertilizers was observed to influence plants characters and the number of grains panicle-1 (jahan et al., 2017, sarkar et al., 2014 and rahman et al., 2006). number of effective tillers hill-1 and number of sterile spikelets panicle-1 were not significantly influenced by nutrient management and recorded the highest number of effective tillers hill-1 (6.78). the longest panicle (21.97 cm) in poultry manure @ 5 t ha-1 and the highest number of sterile spikelets panicle-1 (15.91) was observed in control treatment. nitrogenous fertilizer increased the effective tillers was reported by ray et al. (2015). hossain et al. (2010) reported the highest sterility due to lack of nitrogenous fertilizers. numerically, the highest number of non-effective tillers hill-1 (5.22) was found in 50% rf + poultry manure @ 5 t ha-1 while the lowest number of non-effective tillers hill-1 (1.44) was found in 100% recommended dose of inorganic fertilizer treatment. the highest straw yield (7.08 t ha1) was found in 100% rf and the lowest one (6.09 t ha-1) was found in control treatment. rahman et al. (2006) carried out an experiment and reported that nitrogen level significantly influenced yield components. performance of aman rice varieties under different nutrient management 93 table 2. effect of nutrient management on crop characters and yield components of transplant aman rice nutrient management plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) length of panicle (cm) sterile spikelets panicle-1 (no.) grains panicle-1 (no.) 1000 grain wt. (g) harvest index (%) n1 93.90bc 9.24 6.67 1.95b 20.63c 15.91 107.6b 21.78cd 48.17 n2 94.08abc 10.00 6.56 1.44b 20.81bc 14.13 109.02b 23.24ab 46.76 n3 95.46ab 10.33 6.78 1.56b 21.97a 13.76 111.80b 22.29cd 47.09 n4 96.50a 11.74 6.44 1.67b 21.36ab 14.48 115.26a 23.49a 48.20 n5 94.61ab 10.63 6.74 5.22a 21.19abc 14.47 113.00ab 22.59bc 47.62 level of sig. ** ns ns * ** ns * ** ns cv (%) 4.73 3.26 5.13 9.39 4.27 7.17 3.68 5.14 4.56 in a column, mean values with the same letter (s) or without letter do not differ significantly whereas mean values with dissimilar letter differ significantly (as per dmrt). ** = significant at 1% level of probability, * = significant at 5% level of probability, ns = not significant. n1 = control, n2 = 100% recommended dose of inorganic fertilizer, n3 = poultry manure @ 5 t ha-1, n4 = 75% recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1, n5 = 50% recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1 fig. 2. effect of nutrient management on grain and straw yield of t. aman rice the interaction effect between variety and nutrient management was significant on crop characters, yield and yield components of transplant aman rice (table 3 and figure 3). numerically, the tallest plant (99.78 cm), the highest number of total tillers hill-1 (13.22), the highest number of grains panicle-1 (125.63), the highest grain yield (7.10 t ha-1) and the highest straw yield (8.58 t ha-1) were obtained in binadhan-17 × 75% rf + poultry manure @ 5 t ha-1 treatment, but the shortest plant (89.33 cm) was found in binadhan-16 × poultry manure @ 5 t ha-1, the lowest number of total tillers hill-1 (9.85) was produced in binadhan-15 × control, the lowest number of grains panicle-1 (96.26) was produced in binadhan-16 × 100% rf treatment and the lowest grain yield (5.32 t ha-1) was produced in binadhan-16 × control. the lowest values of effective tillers hill-1 (7.11) and straw yield (6.46 t ha-1) were produced in binadhan-16 × poultry manure @ 5 t ha-1 (table 3 & figure 3). pal et al. (2016) and islam et al. (2014) depicted that combined application of chemical fertilizers with manures in a balanced amount influences yield components and yield. similar trend was reported by qian et al. (2011) who mentioned that combined application of organic and inorganic fertilizers increased grain yield of rice. number of non-effective tillers hill-1 was significantly influenced by the interaction of variety and nutrient management. the highest 94 mushtaree et al. number of non-effective tillers hill-1 (2.78) was produced in binadhan-17 × control treatment, while the lowest number of non-effective tillers hill-1 (1.00) was produced in binadhan-17 × poultry manure @ 5 t ha-1. no significant variation was found in panicle length, the number of sterile spikelets panicle-1, 1000-grain weight and harvest index by the interaction of nutrient management and variety (table 3). fig. 3. effect of interaction between variety and nutrient management on grain and straw yield of t. aman rice numerically, the longest panicle (22.22 cm) was observed in binadhan-16 × 50% rf + poultry manure @ 5 t ha-1 and the shortest panicle (20.98 cm) was found in binadhan-16 × 100% recommended dose of inorganic fertilizer. table 3. interaction effect of variety and nutrient management on crop characters and yield components of transplant aman rice variety× nutrient management (v×n) plant height (cm) total tillers hill-1 (no.) effective tillers hill-1 (no.) noneffective tillers hill-1 (no.) length of panicle (cm) sterile spikelets panicle-1 (no.) grains panicle-1 (no.) 1000 grain weight (g) harvest index (%) v1 × n1 94.41bcd 9.85c 7.33 1.52ab 21.62 21.92 107.07ab c 22.00 44.16 v1 × n2 94.11bcd 10.89bc 7.67 1.22b 21.3 22.33 98.22bc 23.00 43.72 v1 × n3 97.44ab 10.22bc 7.11 2.11ab 21.57 22.08 107abc 21.82 45.43 v1 × n4 98.89ab 11.33abc 8.89 1.44ab 21.83 19.17 100.78bc 22.75 43.72 v1 × n5 94.11bcde 10.22bc 8.00 2.22ab 21.26 20.50 98.52bc 22.30 44.75 v2 × n1 92.11bcde 10.33bc 8.78 1.56ab 21.89 22.42 107.33ab c 23.00 44.70 v2 × n2 96.78abc 10.78bc 8.89 1.89ab 21.28 22.17 96.26c 24.5 43.80 v2 × n3 89.33bcde 10.67ab 9.67 1.00b 22.04 21.00 108.6abc 25.30 44.55 v2 × n4 95.56bcd 11.67ab 10.33 1.33b 21.27 16.33 122.52a 26.93 44.54 v2 × n5 89.44bcde 10.56bc 8.11 1.44ab 22.22 20.25 103bc 27.07 42.68 v3 × n1 94.89bcd 11.56ab 8.89 2.78a 22.01 20.50 117.04ab 20.70 47.43 v3 × n2 95.00abc 12.33ab 10.11 2.22ab 20.98 16.75 122.59a 22.45 46.95 v3 × n3 97.44ab 12.01ab 11.56 1.56ab 21.03 16.33 120.11ab 22.10 47.27 v3 × n4 99.78a 13.22a 11.11 2.22ab 21.72 13.83 125.63a 23.20 45.28 v3 × n5 98.11de 12.11ab 10.11 2ab 21.16 15.58 119.44ab 22.89 47.11 level of sig. * * ns ** ns ns * ns ns cv (%) 4.73 3.26 5.13 9.39 4.27 7.17 3.68 5.14 4.56 performance of aman rice varieties under different nutrient management 95 in a column, mean values with the same letter (s) or without letter do not differ significantly whereas mean values with dissimilar letter differ significantly (as per dmrt). ** = significant at 1% level of probability, * = significant at 5% level of probability, ns = not significant. v1 = binadhan15, v2 = binadhan16, v3 = binadhan17 n1 = control, n2 = 100% recommended dose of inorganic fertilizer, n3 = poultry manure @ 5 t ha-1 , n4 = 75% recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1, n5 = 50% recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1 and the highest number of sterile spikelets panicle-1 (22.42) was produced in binadhan-16 × control treatment, but the lowest one (13.83) was produced in binadhan-17 × 75% rf + poultry manure @ 5 t ha-1. the highest harvest index (47.43%) was observed in binadhan-17 × control treatment, while the lowest one (42.68%) was found in binadhan-16 × 50% rf + poultry manure @ 5 t ha-1 treatment. apparently, the highest weight of 1000-grain (27.07 g) was recorded in binadhan-16 × 50% rf + poultry manure @ 5 t ha-1 treatment and the lowest (20.70 g) weight of 1000-grain was recorded in binadhan-17 × control (table 3). from the above discussion it may be concluded that the variety binadhan-17 fertilized with 75% of the recommended dose of inorganic fertilizer + poultry manure @ 5 t ha-1 influenced growth and yield of transplant aman rice. acknowledgement the financial assistance of ministry of science and technology, government of the people’s republic of bangladesh, to conduct the research project is thankfully acknowledged. references adhikari, a., m.a.r. sarkar, s.k. paul and k.k. saha. 2018. impact of nutrient management on the yield performance of some aromatic fine rice (oryza sativa l.) varieties in boro season. arch. agric. environ. sci. 3(3): 245-251. bbs (bangladesh bureau of statistics). 2020. statistical pocket book of bangladesh bureau of statistics, statistics division, ministry of planning, government of the people’s republic of bangladesh. bhowmick, m.k., m.c. dhara, m.k. bag, b. adhikari and c. kundu. 2011. integrated nutrient management in aromatic rice, west bengal. oryza. 48(3): 276-277. gill j.s. and s.s. walia. 2014. influence of fym, brown manuring and nitrogen levels on direct seeded and transplanted rice (oryza sativa l.): a review. res. j. agric. environ. manage. 3: 417-426. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. int. rice res. inst., john wiley and sons. new york, chichester, brisbane, toronto, singapore, p. 680. hossain, m.s., f.i. monshi, a.m.a. kamal and m.f. miah. 2010. grain yield and protein content of transplant aman rice as influenced by variety and rate of nitrogen. j. agrofor. environ. 3(2): 235-238. islam, s.m.m., s.k. paul, m.a.r, sarkar and m.a.m. miah. 2014. growth of transplant aman rice as influenced by weeding regime and integrated nutrient management. bangladesh j. prog. sci. tech. 12(1): 49-54. jahan, s., m.a.r. sarkar and s.k. paul. 2017. effect of plant spacing and fertilizer management on the yield performance of brri dhan39 under old brahmaputra floodplain soil. madras agri. j. 104(1-3): 37-40. 96 mushtaree et al. nayak, b., b.s. rath, m. shahid, s.n. jena, t.b. bagchi and p.s. roy. 2020. organic nutrient management in aromatic rice-rice sequence: a critical review. int. j. chem. stud. 8: 14351444. pal, s., s.k. paul, m.a.r. sarkar and. d.r. gupta. 2016. response on yield and protein content of fine aromatic rice varieties to integrated use of cowdung and inorganic fertilizers. j. crop weed. 12: 1-6. paul, s.k., n.y. nila and m.a.r. sarkar. 2020. grain yield and quality of aromatic boro rice (cv. brri dhan50) subject to date of transplanting and nutrient management. thai j. agric. sci. 53(2): 85−96. paul, n.c., m.t. tasmim, s. imran, m.a. mahamud, j. chakrobortty, r.h.m. rabbi, s.k sarkar and s.k. paul. 2021. nutrient management in fragrant rice: a review. agric. sci. 12: 15381554. paul, s.k., m.c. ray, m.a.r. sarkar and s.k. sarkar. 2019. effect of water, nutrient and weed management on the yield and quality of aromatic boro rice (cv. brri dhan50). bangladesh agron. j. 22: 57-69. qian, h., m.l. xiu, g.l. rong, l. zhang, y.l. ren, y.h. lan, j. hua, s.c. hong, and w.f. quan. 2011. effect of long-term located organic-inorganic fertilizer application on rice yield and soil fertility in red soil area of china. sci. agric. sin. 44(3): 516-523. rahman, m.m. and a. yakupitiyage. 2006. use of fishpond sediment for sustainable aquacultureagriculture farming. int. j. sustain. dev. plan. 1: 192-202. ray, s., m.a.r. sarkar, s.k. paul, a.k.m.m. islam and s. yeasmin. 2015. variation of growth, yield and protein content of transplant aman rice by three agronomic practices. agric. biol. sci. j. 1(4): 167-176. sarkar, s.k., m.a.r. sarkar, n. islam and s.k. paul. 2014. yield and quality of aromatic fine rice as affected by variety and nutrient management. j. bangladesh agril. univ. 12(2): 279–284. sinha, t., s.k. paul and m.a.r. sarkar. 2018. effect of age of seedlings at staggered transplanting and weed management on the growth and yield of aromatic boro rice (cv. brri dhan50). j. bangladesh agril. univ. 16(1): 5-11. microsoft word 12. baj-457e short communication bangladesh agron. j. 2024, 26(2): 100-103 optimization of the priming time of mannitol solution for mungbean seed treatment m.a. rahman1*, m.a. baque1, s. sarmin2 and m.m. elahi3 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh. 2scientific officer, bangladesh institute of research and training on applied nutrition, regional station, jhenaidah, bangladesh. 3department of biotechnology, sher-e-bangla agricultural university, dhaka-1207, bangladesh. *corresponding author, email: mamunsau09@gmail.com (received: 27 june 2023, accepted: 30 june 2024) keywords: pre-sowing, mannitol, priming, mungbean mungbean (vigna radiata l.) is an important grain legume in bangladesh belonging to the family fabaceae. as an excellent source of vegetable protein. its edible grain is characterized by good digestibility, flavor, high protein content, and absence of any flatulence effect. the lysine content makes mungbean a good complementary food for rich-based diets because lysine is usually the first limiting amino acid. besides, the crops can enrich soils through nitrogen fixation (sharma and behera, 2009). plant growth and productivity are affected by nature’s wrath in the form of various abiotic stress factors. plants are frequently exposed to a plethora of stress conditions such as salt, drought, oxidative stress, and others. all these stress factors are a means for plants and prevent them from reaching their full genetic potential and limit crop productivity worldwide. lack of adequate soil moisture in the seedbed is a major obstacle to the establishment of the crop because inadequate soil moisture can reduce germination, slow down seedling growth and decrease yield. there are many strategies have been adopted to overcome the negative effects of drought. a good strategy for overcoming drought stress is seed pre-sowing treatments (ghiyasi et al., 2008). seed priming was defined as pre-sowing treatments in water or in an osmotic solution that allows the seed to imbibe water to proceed to the first stage of germination, but prevents radical protrusion through the seed coat (yari et al., 2012). seed priming techniques have been used to accelerate the emergence of more vigorous plants. primed seeds usually to exhibit an increased germination rate, greater germination uniformity, and greater total germination percentage. increased germination rate and uniformity have been attributed to metabolic repair during imbibitions build-up of germination-enhancing metabolites. in bangladesh, little is known about hydro priming and information regarding seed priming with osmotic priming agents for inducing drought tolerant capability in mungbean in bangladesh. hence, the study is conducted to evaluate the effect of pre-sowing seed treatment with mannitol on the germination behavior of mungbean concerning drought tolerance and to optimize the priming time of the best priming solution concentration on the germination behavior of mungbean. the experiment was conducted at the agronomy laboratory, department of agronomy, shere-bangla agricultural university (sau), sher-e-bangla nagar, dhaka-1207. the experiment was conducted during the period from 13 may 2014 to 15 july 2014 to optimize the priming time of mannitol for enhancing drought tolerance capability in mungbean (v. radiata) under drought stress. the temperature and relative humidity of the laboratory room were recorded daily basis during the study period with a digital thermo hygrometer (termo, tfa, germany). the average minimum and maximum temperature during the study months of the culture room was 17.40 °c to 38.20 °c, respectively and the average minimum and maximum relative humidity were 40% and 89.20%, respectively. a completely randomized design (crd) with five replications used in this experiment. two mungbean varieties namely bari mung-3 and bari mung-6 were used for this experiment. different equipment such as an electric balance, electrical conductivity (ec) meter, petri dish, filter paper, micropipette, forceps, etc. were used for this study. mannitol (c6h14o6) and distilled water were utilized for osmo and hydro-priming in this experiment. the experiment comprises of (a) six levels of priming time viz. 3, 6, 9, 12, 15, 18 hours and (b) five levels of priming agent concentration viz. water, 0, 2, 4, optimization of the priming time of mannitol solution for mungbean seed treatment 101 6, and 8% mannitol (c6h14o6). there are thirty-one treatments viz, t0=seeds without priming (control), t1= seeds primed with water for 3 hours t2= seeds primed with water for 6 hours,t3= seeds primed with water for 9 hour, t4= seeds primed with water for 12 hours,t5= seeds primed with water for 15 hours,t6= seeds primed with water for 18 hours,t7= seeds primed with 2% mannitol solution for 3 hours,t8= seeds primed with 2% mannitol solution for 6 hours,t9= seeds primed with 2% mannitol solution for 9 hours,t10= seeds primed with 2% mannitol solution for 12 hours,t11 = seeds primed with 2% mannitol solution for 15 hours,t12= seeds primed with 2% mannitol solution for 18 hours,t13= seeds primed with 4% mannitol solution for 3 hours,t14= seeds primed with 4% mannitol solution for 6 hours,t15=seeds primed with 4% mannitol solution for 9 hours,t16=seeds primed with 4% mannitol solution for 12 hours,t17=seeds primed with 4% mannitol solution for 15 hours,t18=seeds primed with 4% mannitol solution for 18 hours,t19=seeds primed with 6% mannitol solution for 3 hours,t20= seeds primed with 6% mannitol solution for 6 hours,t21=seeds primed with 6% mannitol solution for 9 hours,t22=seeds primed with 6% mannitol solution for 12 hours,t23=seeds primed with 6% mannitol solution for 15 hours,t24=seeds primed with 6% mannitol solution for 18 hours,t25=seeds primed with 8% mannitol solution for 3 hours, t26 = seeds primed with 8% mannitol solution for 6 hours,t27=seeds primed with 8% mannitol solution for 9 hours,t28=seeds primed with 8% mannitol solution for 12 hours,t29 = seeds primed with 8% mannitol solution for 15 hours and t30=seeds primed with 8% mannitol solution for 18 hours 2%, 4%, 6%, and 8% of mannitol solution and distilled water were used as priming solutions. priming is done in different plastic containers covered with lids to prevent evaporation loss. seeds were removed from the priming solution at the required time. the primed seeds were rinsed thoroughly with distilled water for three times and dried lightly using blotting paper and finally, air dried near to the original weight (umair et al., 2011) at room temperature for 24 hours back to the original moisture level. a sample of 50 seeds was taken from each treatment, and placed in a 250 ml flask with 200 ml of distilled water. the flasks were stirred to remove air bubbles and floating seed, covered with aluminum foil, and kept at room temperature for 24 hours. after soaking, seeds were gently swirled and the conductivity of the soaked water was measured with a dip-type cell (cell constant of 1.0) conductivity meter. conductivity was expressed on a weight basis in ds m−1 g−1 of seed (ista, 1993). the data were statistically analyzed to observe the significant difference among the treatments and the mean was estimated by the least significant difference (lsd) test at 5% level of significance. computer software mstat-c was used to carry out the statistical analysis. the electrical conductivity was significantly influenced by priming (water and mannitol) time (table 1). electrical conductivity gradually decreases up to 9 hours in both water and mannitol priming seeds and gradually increases after 9 hours for both water and mannitol priming seeds. results revealed that the lowest ec 0.0660 ds m−1 was recorded from t9 treatment at 9 hours for bari mung-3, on the other hand, the lowest ec 0.1110 ds m−1 was observed from t21 treatment at 9 hours for bari mung-6. the highest ec 0.3636 ds m−1 and 0.5953 ds m−1 was recorded in the control treatment for both varieties. the probable reason for the reduction of ec value of the hydro-primed and mannitol-primed seed may be priming might have enhanced the repair of cell membranes that were disrupted during aging (senaratna et at., 1988). the repair of the membrane could initiate there-activation or re-synthesis of membrane-bound enzymes and enhanced germination (rao et al., 1987). similarly in canola seeds, ec from the leachate of osmo-primed and hydro-primed seeds was lower than that of non-primed seeds. seed priming was effective in decreasing the ec of seed leachates, which show membrane stability. decreased leakage of solute from primed seed may be because of better membrane repair during hydration (fu et al., 1988). table 1. effect of different priming times on electrical conductivity of primed (mannitol and water) and non-prime (control) seeds treatments electrical conductivity (ds m−1) bari mung-3 bari mung-6 t0 0.3636 a 0.5953 a t1 0.1010 m 0.2220 kl t2 0.0909 n 0.1816 m 102 rahman et al. t3 0.0707 p 0.1514 no t4 0.1111 l 0.2321 k t5 0.1212 k 0.2725 i t6 0.1313 j 0.2926 h t7 0.0909 n 0.2119 l t8 0.0808 o 0.1614 n t9 0.0606 q 0.1413 o t10 0.1010 m 0.2321 k t11 0.1111 l 0.2725 i t12 0.1313 j 0.2926 h t13 0.1010 m 0.1816 m t14 0.0909 n 0.1614 n t15 0.0757 op 0.1413 o t16 0.1111 l 0.2220 kl t17 0.1212 k 0.2523 j t18 0.1414 i 0.2825 hi t19 0.1515 h 0.1816 m t20 0.1414 i 0.1614 n t21 0.1515 h 0.1110 p t22 0.1717 g 0.2220 kl t23 0.1717 g 0.2321 k t24 0.1717 g 0.2725 i t25 0.1818 f 0.3229 g t26 0.1717 g 0.3635 f t27 0.2121 e 0.3834 e t28 0.2424 d 0.4238 d t29 0.2525 c 0.4843 c t30 0.2626 b 0.5054 b lsd(0.05) 0.0079 0.012 cv (%) 4.54 4.07 from the results of the study, it may be concluded that priming with 2% mannitol concentration for bari mung-3 and 6% mannitol concentration for bari mung-6 with 9 hours priming time increases the germination behavior of mungbean seeds. reduction in germination parameters and seedling growth was more profound in control seeds than primed seeds under drought stress conditions. thus, optimized priming time may be an effective method to meet the demands of farmers during the installation of the culture in the field and especially in conditions of drought stress. references fu, j.r., r.z. lu, r.z. chen, z.s. hang, z.s. liti and d.y. cal. 1988. osmoconditioning of peanut seeds with peg to improve vigor and some biochemical activities. seed sci. technol. 16:197-212. ghiyasi, m., m.p. myandoab, m. tajbakhsh, h. salehzadeh and m.v. meshkat. 2008. influence of different osmopriming treatments on emergency and yield of maize (zea mays l.). j. biol. sci. 3(12): 1452-1455. ista. 1993. handbook for seedling evaluation. international seed testing association, zurich, switzerland. rao, s.c., s.w. akens and r.m. ahriuj. 1987. priming brassica seeds to improve germination under different temperature and moisture conditions. crop sci. 27:1050-1053. senaratna, t., j.f. gusse and b.d. mckersie. 1988. aeging induced changes in cellular membranes of imbibed soybean seed axes. physiol. plant. 73:85-91. sharma, a.r. and u.k. behera. 2009. nitrogen contribution through sesbania green manure and dual-purpose legumes in maize-wheat cropping system: agronomic and economic considerations. plant soil. 325: 289304. umair, a., s. ali, r. hayat, m. ansar and m. tareen. 2011. evaluation of seed priming in mungbean (vigna radiate l.) for yield, nodulation, and biological nitrogen fixation under rainfed conditions. afr. j. biotechnol. 10(79):18122-18129. yari, l., s. sheidale, h. sadeghi and f. khazaei. 2012. evaluation of temperature and seed priming duration on seed germination behavior of rice (oryza sativa l.). intl. j. agric res. rev. 2(1): 7-12. optimization of the priming time of mannitol solution for mungbean seed treatment 103 crop management bangladesh agron. j. 2024, 27(2): 78-89 effect of integrated weed management practices on weed growth and yield of sorghum in winter s.s. kakon*, s.s. nasreen, a.a. begum, j.a. chowdhury, m.z.a. mantu, s.t. zannat and m.a.h. khan agronomy division, bangladesh agricultural research institute, gazipur 1701, bangladesh *corresponding author, email: kakonbari@gmail.com (received: 13 june 2025, accepted: 28 august 2025) keywords: sorghum, weed management, weed dry matter, weed control efficiency, yield abstract the field experiment was conducted at agronomy division, bangladesh agricultural research institute, gazipur, during rabi season of 2022-23 and 2023-2024 to study the effect of integration of chemical and cultural methods for weed management in sorghum. there were seven treatment viz. t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 das + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1 spraying as pre-emergence and t7= no weeding and no herbicide were included in the experiment. barnyard grass (echinochola crusgalli), harkuch (enhydra fluctuans), nutsedge (cyperus rotundus) and jersey cudweed (gnaphalium affine) were the common and dominant weeds in the sorghum field. results showed that the highest weed control efficiency (wce) (84.4% at 25 days after establishment (dae) and 90.2% at 45 dae at 2022-23 and 85.28% at 25 dae and 81.58% at 45 dae at 2023-24) was found in t2 treatment. significantly the highest two years average yield (3.64 kg ha−1) was obtained from t5 treatment. the highest gross return of (tk. 109300 ha−1) and benefit cost ratio (bcr) (2.01) were also obtained from t5 treatment. from the result it might be concluded that, two herbicides (atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das and pendimethalin@ 3 l ha−1spraying as pre-emergence + one hand weeding at 25 das) were found economical by recording higher net returns and bcr compared to control. introduction sorghum (sorghum bicolor l.) is considered as king of millets and extensively grown in semiarid tracks of africa, china and india. the area under sorghum cultivation was recorded as 6316 acres in 1996-1997 but it continuously decreased and reached to 745 acres in 2017-2018 (bbs, 2018). it has multiple uses as grain, fodder and more recently as bifo energy crop. in asia and africa sorghum grain is consumed by human or as animal feed, stalks are used as fodder or housing material. sorghum has a high nutritive value, with 70-80% carbohydrate, 11-13% protein, 2-5% fat, 1-3% fibre, and 1-2% ash. protein in sorghum grain is gluten free and thus it is specifically a food for people who suffer from celiac disease (intolerant to food with gluten), including diabetic patients. comparing the production potential of sorghum, the low productivity in bangladesh is attributed to several reason. among them weed is a major constrains. weeds are major problems in increasing productivity of the crop. it was reported that yield loss of sorghum due to weeds ranges from 15-97%, depending on the nature and density of weeds (thakur et al. 2016). weeds germinated fast and grow rapidly at initial growth period of crops competing with the crops 79 kakon et al. severely for growth resources, viz. nutrients, moisture, sunlight and space. this affects the growth and development of crop and leads to yield losses (freitas et al., 2014). weed management in grain sorghum is a challenge because of the limited number of herbicides available to growers, rotational crop restrictions following a number of herbicides registered for use in grain sorghum and presence of herbicide resistant weeds. traditional hand weeding is the most efficient and widely adopted practice of weed management but it is labor intensive, time consuming and not economical due to high wage rates. mechanical equipment can be time saving during peak operation, resulting in higher output per worker and reduction in the cost of weeding. chemical weed control is a better supplement to conventional method however the weed emergence pattern, application timing and stage of crop are important in chemical control. continuous use of herbicides over a prolonged time leads to development of resistance in weeds making them difficult to control. integrated weed management (iwm), the process of combining several single management strategies together to suppress weeds has been developed. hence, various components of integrated weed management are to be blended in a systematic way to achieve the acceptable level of weed control. the integration of herbicides with cultural operations and use of pre-emergence and post-emergence herbicides in combination with mechanical methods will makes the crop weed free effectively and thus, improves the crop growth as well as yield. the integrated weed management is, therefore, gaining importance in management of weeds for preventing yield losses and higher input-use efficiency. herbicide application in bangladesh is expected to increase in future due to labor scarce situation. the present investigation was carried out to study the effect of integrated weed management practices on weed density, weed dry weight and economics in sorghum. materials and methods field experiment was conducted at the research farm of bangladesh agricultural research institute, gazipur during rabi season of 2022-2023 and 2023-2024. the experiment site was located chhiata series under agro-ecological zone-28 (aez-28) latitude 23059’ n and longitude 90024’ e. the meteorological data of the experimental site revealed that the highest temperature prevails in march-april and the lowest in december to january. maximum rainfall was received during the months of january. the crop received 543 mm rain showers from november to march in 2023-24years. the average maximum (32.08 °c) was found in the month of march during the crop growing season (fig. 1.) and minimum (12.77 °c) temperature in the month of january during the crop growing season (fig. 1.). the experiment was consisted of seven treatments viz. t1 = two hand weeding at 25 and 40 das, t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das, t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 das, t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 das + one hand weeding at 40 das, t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence + one hand weeding at 25 das, t6 = pendimethalin @ 3 l ha−1 spraying as pre-emergence and t7= no weeding and no herbicide. the experiment was laid out in randomized complete block design with three replications. the unit plot size was 3m × 3m. seeds of sorghum (bari sorghum-1) were sown on 25 november, and harvested on 1 april, 2023 and 2nd year sown on 28 november 2023 and finally harvested on 5 april 2024. fertilizers were applied at the rate of 120-60-50 kg ha−1 of npk as urea, triple superphosphate (tsp), muriate of potash (mop) for grain sorghum. one third n and all other fertilizers were applied as basal. rest n was be applied at 20 and 40 das. three times of irrigation were applied in field. weed sample were collected (1 m2 per each plot) at 25 das and 45 das and dry matter was taken after oven dry. weed control efficiency (wce) was calculated according to following formula: weed control efficiency (wce%) = ( 𝐴−𝐵 𝐴 ) × 100 effect of integrated weed management practices on weed growth and yield of sorghum 80 where, a = dry weight of weeds in no weeding plots and b = dry weight of weeds in treated plots. yield and yield contributing characters were recorded and pooled data analyzed statistically with statistics 10 statistical package. the means were separated by least significant difference test (lsd 0.05%). fig. 1. mean temperature and rainfall prevailed during sorghum growing periods at gazipur results and discussion weed species and their relative density and number of weeds m−2 in different treatments are presented in table 1.the weeds flora infesting the sorghum field were harkuch (enhydra fluctuans), barnyard grass (echinochloa crusgalli), scrab grass (digitaria sanguinalis), kanainala (cyanotis axillaris), goose grass (eleusine indica), nutsedge (cyperus rotundus), vetch (vicia sativa), bitter dock (rumexm aritimus), bermuda grass (cynodon dactylon), lambsquarte (chenopodium album), alligator weed (alternanthera philoxeroides), paspalum grass (paspalum commersonii), hatishur (heliotropium indicum) and pig weed (amaranthus viridis). among the weed species, barnyard grass (echinochloa crusgalli), harkuch (enhydra fluctuans), nutsedge (cyperus rotundus), bermuda grass (cynodon dactylon) and jersey cudweed (gnaphalium affine) were the common and dominant weeds in the sorghum field. the relative density of the major weed species among the treatments ranges from 18.81-74.04, 1.78-23.33,2.96-20,2.12 -6.29 and 16.97 -33.86%, respectively. c. dactylon, e.crusgalli, c. rotundus, g. affine and e. fluctuansat 25 days after emergence (dae). d. sanguinalis, e. indica, c. rotundus, v. sativa and r. maritimus occured in lesser number at 25 dae. at 45 dae, c. dactylon, e. crusgalli, c. rotundus and g. affine were found as major weeds with their relative density among the different treatments ranges from 7.17-45.24, 3.00-13.33, 1.63-24.39 and 2.22-25.09%, respectively. e. fluctua, p. commersoni, a. viridis, h. indicum and c. album occurred in lesser number. two hand weeding (hw) recorded significantly lower number of all the weed m−2 at 25 and 45 dae. at 25 dae, among the weed management plots the number of weeds ranged from 40 to 63 m−2. the highest weed population (106 m−2) was recorded in t7 treatment at 25 dae. at 45 dae, numbers of weeds ranged from 45 to 82 m−2. the highest weed population (186 m−2) was recorded in t7 treatment at 45 dae. the number of weeds were increased in all the plots at 45 dae than 25 dae. among the chemical treatments, application of atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das, pendimethalin @ 3 l ha−1 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 40 n o v. 1 n o v. 7 n o v. 1 3 n o v. 1 9 n o v. 2 5 d e c. 1 d e c. 7 d e c. 1 3 d e c. 1 9 d e c. 2 5 d e c. 3 1 j a n .6 j a n .1 2 j a n .1 8 j a n .2 4 j a n .3 0 f e b .5 f e b .1 1 f e b .1 7 f e b .2 3 m a r. 1 m a r. 7 m a r. 1 3 m a r. 1 9 m a r. 2 5 m a r. 3 1 6 -a p r m a x . a n d m in . te m p e ra tu re ( 0 c) date and month min max raifall r ain fall (m m ) 81 kakon et al. spraying as pre-emergence + one hand weeding at 25 das and atrazine @ 2 l ha−1 spraying as post-emergence at 15 das + one hand weeding at 40 das were very effective in controlling the weeds which recorded a weed density of 45 and 49, respectively (table 1). table1. effect of different of weed management method on weed species, weed number m−2 and weed density (%) over time average two years treatment english name scientific name 25 dae 45 dae number of weed m−2 weed density (%) number of weed m−2 weed density (%) t1 scrab grass digitaria sanguinalis 4 4.88 nutsedge cyperus rotundus 8 20.00 1 1.63 alligator weed alternanthera philoxeroides 7 8.13 harkuch enhydra fluetuans 8 20.00 vetch vicia satiua 4 4.88 barnyard grass echinochloa crusgali 9 23.33 9 11.38 jersey cudweed gnaphalium affine 4 4.88 bitter dock rumexm aritimus 3 6.67 3 3.25 goose grass eleusine indica 3 6.67 bermuda grass cynodon dactylon 9 23.33 12 14.63 kanai nala cyanotis axillaris 1 1.63 total 40 45 t2 nutsedge cyperus rotundus 1 2.96 3 4.94 alligator weed alternanthera philoxeroides 21 39.51 lambsquarte chenopodium album 1 2.96 harkuch enhydra fluetuans 9 20.74 barnyard grass echinochloa crusgali 1 2.96 5 9.88 jersey cudweed gnaphalium affine 4 7.41 goose grass eleusine indica 4 7.41 bermuda grass cynodon dactylon 33 74.07 17 32.10 total 45 55 t3 scrab grass digitaria spp 11 13.01 nutsedge cyperus rotundus 3 5.03 alligator weed alternanthera philoxeroides 20 24.39 lambsquarter chenopodium album 1 2.52 harkuch enhydra fluetuans 16 21.33 barnyard grass echinochloa crusgali 1 1.78 7 8.13 jersey cudweed gnaphalium affine 4 4.88 pig weed amaranthu sviridis 3 3.25 bitter dock rumex maritimus 1 1.63 goose grass eleusine indica 3 3.56 5 6.50 bermuda grass cynodon dactylon 29 55.35 31 37.40 total 53 82 t4 scrab grass digitaria sanguinalis 3 4.76 nutsedge cyperus rotundus 3 4.23 9 16.67 alligator weed alternanthera philoxeroides 16 28.57 lambs quarter chenopodium album 1 2.12 effect of integrated weed management practices on weed growth and yield of sorghum 82 treatment english name scientific name 25 dae 45 dae number of weed m−2 weed density (%) number of weed m−2 weed density (%) harkuch enhydra fluetuans 21 33.86 barnyard grass echinochloa crusgali 11 16.93 2 3 jersey cudweed gnaphalium affine 1 2.12 3 4.76 goose grass eleusine indica 1 2.12 bermuda grass cynodon dactylon 25 40.21 25 45.24 total 63 56 t5 scrab grass digitaria sanguinalis 7 11.11 nutsedge cyperus rotundus 4 6.67 alligator weed alternanthera philoxeroides 25 42.22 lambs quarter chenopodium album 3 5.44 harkuch enhydra fluetuans 12 24.49 barnyard grass echinochloa crusgali 3 5.44 8 13.33 jersey cudweed gnaphalium affine 1 2.22 goose grass eleusine indica 4 8.16 bermuda grass cynodon dactylon 27 54.42 15 24.44 total 49 60 t6 scrab grass digitaria spp 5 9.36 nutsedge cyperusrotundus 5 9.70 5 9.36 alligator weed alternantheraphiloxeroides 11 18.71 lambs quarter chenopodium album 1 2.42 harkuch enhydra fluetuans 9 16.97 vetch vicia satiua 4 7.02 barnyard grass echinochloa crusgali 7 12.12 3 4.68 jersey cudweed gnaphalium affine 3 4.68 bitter dock rumexm aritimus 7 11.70 goose grass eleusineindica 5 7.27 4 7.02 bermuda grass cynodon dactylon 27 48.48 15 25.73 total 55 57 t7 scrab grass digitaria sanguinalis 4 3.77 21 11.47 nutsedge cyperus rotundus 11 10.06 4 2.15 alligator weed alternanthera philoxeroides 28 15.05 hatisur heliotra piumindicum 7 3.58 paspalum grass paspalum commergonii 3 1.43 harkuch enhydra fluetuans 23 21.38 vetch vicia satiua 4 2.15 barnyard grass echinochola crusgali 15 13.84 17 9.32 jersey cudweed gnaphalium affine 7 6.29 47 25.09 pig weed amaranthus viridis 4 3.77 3 1.43 wild radish raphanus rahanistrum 4 3.77 bitter dock rumex maritimus 4 3.77 25 13.62 goose grass eleusine indica 7 6.29 11 5.73 bermuda grass cynodon dactylon 20 18.87 13 7.17 lambs quarter chenopodium album 7 6.29 3 1.43 total 106 186 t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence +weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 das + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1 spraying as pre-emergence and t7= no weeding and no herbicide 83 kakon et al. the present results are in agreement with the earlier findings of priya and kubsad (2013). sorghum in very early stages of crop development grows slowly and competes weakly with weeds. this is the critical time and a small amount of weed in the field will cause a substantial reduction in yield (saini et al., 2018). hence the above treatments were effective in controlling the weeds in the earlier stages of the crop producing very low weed density. the weeds were very densely populated in the control plot. herbicides in combination with good cultural practices would effectively reduce the density of the weed population in crop production (greer and denman, 1983). the dry matter of the weeds was influenced by different weed control strategies (table 2). as the level of herbicides or weed control practices increases there was a great decrease in the dry matter accumulation by weeds (shakoor et al., 2000). the treatment atrazine @ 2 l ha−1 as pre-emergence + one hand weeding at 25 das producing comparatively lower weed dry weight (21.0 g m−2 at 25 dae and 30.7 g m−2 at 45 dae at 2022-23 and 5.10 g m−2at 25 dae and 63 g m−2 at 45 dae at 2023-24). other than the above treatments, dry matter accumulation by the weed was controlled effectively by two hand weeding @ 25 and 40 das, atrazine @ 2l ha−1 as post emergence + one hand weeding at 45 das and pendimethalin @ 3l ha−1 as preemergence + one hand weeding at 25 das. the reason for the low dry matter accumulation by the weed in different weed management practices is because of their effectiveness in suppressing the weeds. these results were in similarity with the findings of shakoor et al., (2000). on the other hand, highest weed dry matter was accumulated in the (t7) weeded plots (128.7 g m−2 at 25 dae 314.7 g m−2 at 45 dae at 2022-23 and 34.67 g m−2 at 25 dae 342 g m−2 at 45 dae at 2023-24) as the crops in the treatment was completely competed by the weeds because of the non-interference in the growth of weeds utilizing maximum resources (deshmukh and usadadia, 2017). weed control efficiency (wce) denotes the magnitude of weed reduction due to weed control treatment (mani et al., 1973). the wce was affected by different treatment. the highest wce (84.4% at 25 dae and 90.2% at 45 dae at 2022-23 and 85.28% at 25 dae and 81.58% at 45 dae at 2023-24) was found in t2 (atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) treatment. priya and kubsad (2013), pandey et al., 2001 and thakur et al., 2016 have also obtained similar effect of various weed control treatments on wce. table 2. weed dry weight (g m−2) and weed control efficiency at 25 dae and 45 dae as affected by different treatments during rabi seasons of 2022-23 and 2023-24 treatment dry weight of weed (g m−2) weed control efficiency (%) 2022-23 2023-24 2022-23 2023-24 25 dae 45 dae 25 dae 45 dae 25 dae 45 dae 25 dae 45 dae t1 21.3 36.7 8.69 84.70 83.5 88.2 74.92 75.23 t2 21.0 30.7 5.10 63.00 84.4 90.2 85.28 81.58 t3 24.7 52.7 6.29 77.76 80.7 83.2 81.86 77.26 t4 25.3 38.7 6.78 81.00 80.4 87.5 80.44 76.32 t5 23.0 44.7 6.67 76.50 82.1 85.6 80.77 77.63 t6 25.7 37.3 6.10 94.50 80.2 87.9 82.40 72.37 t7 128.7 314.7 34.67 342.00 00 00 00 00 t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 das + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1spraying as pre-emergence and t7= no weeding and no herbicide effect of integrated weed management practices on weed growth and yield of sorghum 84 leaf area index leaf area index (lai) varied as influenced by different weed management practices (fig. 2). leaf area index did not differ at 30 dae among the different weed management treatment but markedly differed at 60 dae and up to 75 dae. treatment t2 (atrazine @ 2 l ha−1 spraying as pre-emergence +one hand weeding at 25 das) and t5(pendimethalin @ 3 l ha−1spraying as pre-emergence + one hand weeding at 25 das) gave the maximum lai of 3.38 and 3.31 at 75 dae followed by t1 and t4. treatment t7 gave the lowest lai of 1.89. similar findings were obtained by suseendran et al., (2019). fig 2. leaf area index (lai) of sorghum at different dae as influenced by different weed management. here,t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence +one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence +weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 days after sowing (das) + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1spraying as pre-emergence and t7= no weeding and no herbicide total dry matter production total dry matter (tdm) accumulation in sorghum increased over time as influenced by different weed management methods (fig.3). difference in tdm production per unit area among the treatments started sharply from 60 dae then increased rapidly up to 90 dae and then increased slowly up to harvest. the maximum amount (1987 gm−2) of tdm per unit area was recorded in t2 (atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 dae) followed by t5, t4 and t1 treatment and it was higher than other treatments throughout the growing period. the lowest tdm was observed in t7 (no weeding and no herbicide) treatment followed by t6 treatment. it might be due to better utilize the growth resources for growth and development as compared to other treatments and produced maximum tdm and t7 treatment produced the minimum tdm (1163 g m−2). similar findings were also observed by bari (2008). 0 0.5 1 1.5 2 2.5 3 3.5 4 30dae 45dae 60dae 75dae 90dae at harvest l e a f a re a i n d e x days after emergence t1 t2 t3 t4 t5 t6 t7 85 kakon et al. fig. 3. total dry matter accumulation of sorghum at different dae as influenced by different weed management. here, t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 days after sowing (das) + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as preemergence +one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1 spraying as pre-emergence and t7= no weeding and no herbicide crop growth rate crop growth rate (cgr) values of sorghum increased progressively with time in different weed management methods (fig.4) except t7 (no weeding and no herbicide). the cgr values declined from 90 dae in t7 because of maximum crop weed competition. treatment t2 (atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das )gave the maximum cgr values of 45.89 gm−2 day−1 at 90-75 dae, which was followed by t1(43.13g m−2 day−1), t4 (44.49 g m−2 day−1) and t5 (44.12 g m−2 day−1) treatment. leaf area index, tdm and cgr values of sorghum under different weed management methods indicate that application of atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das and pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das) had no adverse effect on sorghum. the results are in agreement with the reports of bari (2008). 0 500 1000 1500 2000 2500 30dae 45dae 60dae 75dae 90dae at harvest t o ta l d ry m a tt e r (g m -2 ) days after emergence t1 t2 t3 t4 t5 t6 t7 effect of integrated weed management practices on weed growth and yield of sorghum 86 fig.4. crop growth rate of sorghum at different dae as influenced by integrated weed management. here, t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as preemergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 days after sowing (das) + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1 spraying as pre-emergence and t7= no weeding and no herbicide plant height, yield and yield component of sorghum plant population m−2, plant height at harvest, yield and yield components of sorghum were significantly affected by different weed management methods (table 3). plant population per unit area varied from 12 to 16 m−2. the highest population (16 m−2) was recorded from treatment t3, t4, t1, t5 and t6 which were identical to treatment t2. the lowest population (12 m−2) recorded in t7 treatment. the highest plant height (134.32 cm) was found in t5 (pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) treatment which was followed by t1, t2, t3 and t4 treatments. the height of the plants was high on the above treatments is because that these treatments are effective in controlling the weeds hence offering less competition to the crop and the lowest plant height (109.67 cm) was observed in t7 (no weeding and no herbicide) treatment. this might be due to severe crop weed competition throughout the crop growth period, which adversely hampered the normal expansion of the crop (patel et al., 2014). the longest (17.97 cm) panicle was observed in t2 (atrazine @ 2 l ha−1spraying as pre-emergence + one hand weeding at 25 das) treatment which was followed by t1, t3, t4, t5 and t6 treatments and the shortest (14.50 cm) was in t7 treatment. long panicle had higher number of grains panicle−1. the highest number of grain panicle−1 (948) was found in t2 (atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) treatment which was statistically similar to t1 and t5 treatments and the lowest number of grain panicle−1 (680) was observed in t7 treatment. the highest 1000-grain weight (35.34 g) was obtained in t5(pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) treatment which was satistically similar to t1 and t2 treatments and the lowest (29.12g) was observed in t7 treatment. similar findings was observed in kumar et al., (2012). significantly the maximum grain yield (3.64 tha−1) was found in t5 (pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) treatment. however, it was 0 5 10 15 20 25 30 35 40 45 50 45-30dae 60-45 dae 75-60dae 90-75dae harves-90dae c ro p g ro w th r a te (g m -2 d a y -1 ) days after emergence t1 t2 t3 t4 t5 t6 t7 87 kakon et al. statistically similar with atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das (3.55 t ha−1), atrazine @ 2 l ha−1spraying as post-emergence at 25 das + one hand weeding at 40 das (3.36 t ha−1) and two hand weeding at 25 and 40 das (3.37 t ha−1), respectively and the minimum grain yield (1.74 t ha−1) was observed in t7 treatment. vigorous weed growth and severe crop weed competition drastically reduced crop yield of the control plots. however, the reduction of yield under t7 treatment was 48% in compared with weed free throughout the growing period (t1) followed by the reduction of 52% from t5 treatment. the highest grain yield was attributed by the highest number of grain panicle−1 and 1000grain weight (table 3). the higher yields obtained on the above treatments was due to the fact that there was reduced crop weed competition as lesser or no weeds had been observed on the above treatments. because of that reason the availability of soil moisture, nutrients, light and other resources to the plants was very high and hence promoted higher yields. these results are in corroboration with the earlier findings of mishra et al. (2012), ramakrishna et al. (1991) and thakur et al. (2016). table 3. plant population m−2, plant height, yield and yield components of sorghum as affected by different weed management methods during rabi season of 2022-24 treatment number of plant population m−2 plant height at harvest (cm) length of panicle (cm) . grains panicle−1(no) 1000-grain weight (gm) grain yield (t ha−1) t1 14 127.77 17.00 895 34.40 3.37 t2 16 134.32 17.97 948 34.55 3.55 t3 15 128.34 17.22 827 31.88 2.73 t4 15 126.11 17.56 870 34.19 3.36 t5 17 124.45 18.11 943 35.34 3.64 t6 15 114.56 16.35 813 29.93 2.58 t7 13 109.67 14.50 680 29.12 1.74 lsd (0.05) 2.20 10.54 1.79 50.16 0.27 2.74 cv (%) 8.05 4.79 5.94 3.30 4.71 5.01 t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 day after sowing (das) + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1spraying as pre-emergence and t7= no weeding and no herbicide cost return performance economic analysis of different weed management practices on sorghum production was done (table 4). from the cost and return analysis it was found that the highest gross return (tk. 109300 ha−1) and gross margin (tk. 54370 ha−1) was recorded in t5 (pendimethalin @ 3 l ha−1 spraying as pre-emergence + one hand weeding at 25 das). the highest average yield with highest gross return was obtained from t5 treatment and this was followed by application of atrazine 2 l ha−1 + one hand weeding at 25 das (t2). the lowest gross margin was in t7 treatment (tk. 5485 ha−1). the highest bcr was obtained from t5 (pendimethalin @ 3 l ha−1 as pre-emergence + one hand weeding at 25 das) (2.01) followed by t2 (1.96) treatment and the lowest benefit cost ratio was in t7 (no weeding and no herbicide) (1.12) treatment. hence, both the treatments (pendimethalin @ 3 l ha−1 and atrazine 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 das) gave the highest return and bcr. effect of integrated weed management practices on weed growth and yield of sorghum 88 table 4. cost and return analysis of sorghum as affected by different weed management method in 202223 and 2023-24 treatment yield (t ha−1) gross return (tk. ha−1) cost of cultivation (tk. ha−1) gross margin (tk. ha−1) bcr t1 3.37 101220 62730 38490 1.61 t2 3.55 106525 54380 52145 1.96 t3 2.73 81910 55345 26565 1.48 t4 3.36 100760 56325 44435 1.79 t5 3.64 109300 54370 54930 2.01 t6 2.58 77275 52230 25045 1.48 t7 1.74 52265 46780 5485 1.12 t1 = two hand weeding at 25 and 40 days after sowing (das), t2 = atrazine @ 2 l ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t3 =atrazine @ 2 l ha−1 spraying as pre-emergence + weeding by bari weeder at 25 days after sowing (das), t4 = atrazine @ 2 l ha−1 spraying as post-emergence at 25 day after sowing (das) + one hand weeding at 40 days after sowing (das), t5 = pendimethalin @ 3 l ha−1spraying as pre-emergence + one hand weeding at 25 days after sowing (das), t6 = pendimethalin @ 3 l ha−1spraying as pre-emergence and t7= no weeding and no herbicide. sorghum-30 tk.kg−1 conclusion from the present investigation it can be concluded that pre-emergence application of atrazine @ 2 l ha−1+ one hand weeding at 25 das and pendimethalin @ 3 l ha−1 + one hand weeding at 25 das proved practically more convenient and economically best feasible integrated weed management practice for sorghum considering the present condition of scarcity and high cost of labors, quality weed control, yield and money invested of cultivation of sorghum. references bari (bangladesh agricultural research institute). 2008. effect of different weed management methods on growth and yield of mungbean. in: annual report. agronomy div. bangladesh agril. res. int. gazipur. pp. 13-17. bbs.2018. yearbook of agricultural statistics of bangladesh. bangladesh bureau of statistics. ministry of planning, government of the peoples republican bangladesh. deshmukh, s. p. and v.p. usadadia. 2017. weed management influence on crop-weed competition in sorghum under south gujarat conditions. indian j. weed sci. 49(3):272-275. freitas, r.d. a.c.s. hirata, c.j.b. albuquerque and w.l.b. borges. 2014. integrated weed management of sorghum. informe agropecuario. 35(278): 112-119. greer, h.a.l. and c.e. denman.1983. weed control in grain sorghum. osu extension facts, cooperative extension service no. 2763, oklahoma state university, usa kumar, v., s. tyagi and d. singh. 2012. yield, n uptake and economics of fodder sorghum and associated weeds as affected by different weed management practices. prog. agric. 12(1): 96–102. mani, v.s., m.l. malla, k.c. gautam and b. bhagwndas. 1973. weed killing chemicals in potato cultivation. indian farm. 1973:17-18. mishra, j. s., s.s. rao and a. dixit. 2012. evaluation of new herbicides for weed control and crop safety in rainy season sorghum. indian j. weed sci. 44(1): 71-72. pandey, i.b., s.l. sharma, s. tiwari and v. bharati. 2001. effect of tillage and weed management on grain yield and nutrients removal by wheat (triticum aestivum) and weeds. indian j. weed sci. 33(3, 4): 107-111. patel, z.n., b.g. solanki, b.d. jadhav, j.g. patel, s.j. trivedi and j.r. patel. 2014. integrated weed management in kharif sorghum. in: proceedings of 10th combined joint agresco meeting, natural resource management sub-committee. navsari agricultural university, navsari, 96-100. 89 kakon et al. priya, h.r. and v.s. kubsad. 2013. integrated weed management in rainy season sorghum (sorghum bicolor). indian j. agron. 58(4): 548–553. ramakrishna, a., c.k. ong and s.l.n. reddy. 1991. studies on integrated weed management in sorghum. trop. pest manag. 37(2): 159-161. saini, l.h., b.k. davda, s.j. trivedi and a.k. saini. 2018. integrated weed management in sorghum under south gujarat conditions. j. pharmacogn. phytochem.7(5): 510-513. shakoor, a., s. islam, m. naeem. 2000. efficacy of different herbicides for control of weeds in sorghum (sorghum bicolor l) under rainfed conditions. pakistan j. biol. sci. 3(3):463-465. singh, s., u.s. tiwana, m. goyal, u. rani and m.s. bhullar. 2019. evaluation of different pre-and postemergence herbicides on forage yield, quality and disease reaction of multi-cut forage sorghum (sorghum bicolor). indian j. agron. 64(1): 93-97. suseendran, k., p. stalin, c. kalaiyarasan, s. jawahar and g. murugan. 2019. effect of integrated weed management practice on weed growth, yield attributes and yield of irrigated maize (zea mays l.). j. pharmacogn. phytochem.8(2): 1583-1586. thakur, n.s., b.b. kushwaha, o.p. girothia, n.k. sinha and j.s. mishra. 2016. effect of integrated weed management on growth and yields of rainy-season sorghum (sorghum bicolor). indian j. agron. 61(2): 217-222. thakur, n. s., b. b. kushwaha, d. patil and o. p. girothia. 2016. evaluation of weed management practices for recently released sorghum cultivars (sorghum bicolor l.) under rainfed condition, the bios can.11(4): 2355-2358, (supplement on agronomy). bangladesh agron. j. 2025, 28(1): 23-28 fertilizer recommendation for chilli onion intercropping system i. s. m. farhad1*, h. m. naser1, e. jahan2, m. m. masud1 and m. s. bhuiyan3 1soil science division, bangladesh agricultural research institute, gazipur-1701, bangladesh 2regional laboratory, soil resources development institute, tangail, bangladesh 3on-farm research division, bangladesh agricultural research institute, coxsbazar, bangladesh *corresponding author, e-mail: farhadsau@gmail.com (received: 12 october 2025, accepted: 21 november 2025) keywords: benefit cost ratio, chilli equivalent yield, intercropping, optimum fertilizer abstract an experiment was conducted at central research farm, bari, gazipur during rabi season of 2021-22, 2022-23 & 2023-24 to develop a fertilizer recommendation for chilli with onion intercropping system. six treatment combinations viz. t1= 100% rdcf of chilli + 0% rdcf of onion, t2= 100% rdcf of chilli +10% rdcf of onion, t3= 100% rdcf of chilli + 20% rdcf of onion, t4= 100% rdcf of chilli +30% rdcf of onion, t5= 100% rdcf of chilli +40% rdcf of onion and t6= 100% rdcf of chilli +50% rdcf of onion were tested. the experiment was laid out in randomized complete block design with 3 replications. both chilli and onion significantly influenced by different treatment combinations. significantly the highest yield of chilli (12.18 t ha-1) and onion (8.13 t ha-1) were obtained from t6 treatment (100% rdcf of chilli +50% rdcf of onion) which was statistically similar with t5 treatment (100% rdcf of chilli +40% rdcf of onion). chilli equivalent yield (cyi) progressively increases with the increase of inorganic fertilizers. the results showed that t6 provided the highest cey (21.93 t ha-1) followed by t5 (21.88 t ha-1). the highest net return (430005 tk ha-1) as well as bcr (4.67) were obtained from t5 treatment (100% rdcf of chilli +40% rdcf of onion) whereas the lowest net return (364411 tk. ha-1) as well as bcr (4.28) were observed in t1 treatment (100% rdcf of chilli + 0% rdcf of onion).though t6 treatment gave higher yield over all the treatments yet it showed lower bcr compared to t5 treatment due to higher cost involvement for inorganic fertilizer. introduction in bangladesh, the majority of farmers practice monoculture rather than intercropping. however, intercropping uses nutrients more efficiently and provides greater yield stability than monoculture (seran and brintha, 2010). furthermore, mixed or intercropping can maximize land utilisation and boost productivity when compared to single crops (launay et al., 2009; mucherumuna et al., 2010). in highly populated countries with limited per capita land for agricultural production, intercropping is a crucial strategy for increasing productivity per unit area by intensifying the use of land. one of the major spices grown in bangladesh is chilli, which is often grown as sole crop on char land. farmers of different region especially char areas grow chilli as a sole or sometimes intercropping with onion. from the previous research findings of begum et al. (2015), chilli with onion intercropping system found very productive and profitable for the char land. for the intercropping system of chillies with onions, there is currently no suggested fertilizer dosage. fertilizer management is the most logical approach to increase overall productivity in order to obtain the highest return and crop yield. so, it is necessary to find out the optimum fertilizer dose for chilli with onion intercropping system. 24 farhad et al. materials and methods a field experiment was conducted at central research farm, bari, gazipur (aez-28) during rabi season of 2020-21, 2021-22 & 2022-23 to develop a fertilizer recommendation for chilli with onion intercropping system. the experiment confined with intercropping where chilli was transplanted as main crop and onion was transplanted as companion crop. the variety of chilli and onion were bari morich-4 and bari piaj-4, respectively. before conducting the experiment, initial composite soil samples at a depth of 0-15 cm from the experimental plots were collected and analyzed following standard methods (table 1). table 1. chemical properties of initial soil (0-15 cm depth) of the experimental field at central research farm, bari, joydebpur, gazipur during rabi season the experiment was laid out in a randomized complete block design with three replicates. the unit plot size was 4.0 m  3.0 m. chilli (30 days old seedlings) and onion (40 days old seedlings) transplantation were done on last week of december in all the three consecutive years. one row of onion was sown in between two rows of chilli. line to line spacing of chilli was 40 cm and chilli to onion spacing was 20 cm. plant to plant spacing of chilli and onion was 40 cm and 10 cm, respectively. the experiment was set up with six treatments viz. t1= 100% recommended dose of chemical fertilizer (rdcf) of chilli + 0% rdcf of onion, t2= 100% rdcf of chilli +10% rdcf of onion, t3= 100% rdcf of chilli + 20% rdcf of onion, t4= 100% rdcf of chilli +30% rdcf of onion, t5= 100% rdcf of chilli +40% rdcf of onion and t6= 100% rdcf of chilli +50% rdcf of onion. recommended fertilizer dose was estimated based on the soil test value. recommended dose of chemical fertilizer for chilli was n99.5 p32.6 k64 s9.5 zn0.2 b0.9 kg ha-1 and onion was n108.8p28.5 k75.2s19.6 b1.3kg ha-1. cowdung (5 t ha-1) were applied as a basal in all the plots. the whole amounts of organic manure, phosphorus, sulphur, zinc, boron, half of nitrogen and potassium were applied as basal during final land preparation. remaining nitrogen and potassium were applied in two equal installments at 30 and 60 days after transplantation from 1012 cm away from the base of the plant which could be beneficial for the growth and yield of onion. all the intercultural operations such as irrigation, weeding, insect control etc. were done as and when necessary. chilli was harvested five times at 15 days interval starting from 3rd week of march and onion was harvested in its maturity on 1st week of april in all the three years. ten plants from each plot were tagged at random to take records on different agronomic parameters of chilli and onion. data on yield and yield contributing parameters were recorded and statistically analyzed with the help of statistical package statistix 10 (analytical software. tallahassee, fla, usa) and mean separation was tested by duncan’s multiple range test (dmrt) (steel and torrie, 1960). chilli equivalent yield (cey) was calculated after bandyopadhyay (1984): sample ph om total n k ca mg p s zn b cu fe mn (%) (%) meq 100 g soil−1 µg g−1 soil average 6.1 1.36 0.08 0.18 3.8 2.2 12 16 1.6 0.17 4.0 72 8 critical level 0.12 0.12 2.0 0.5 7 10 0.6 0.2 0.2 4.0 1.0 interpreta tion slight ly acidic low very low low med ium very high med ium me diu m opti mu m low very high very high very high fertilizer recommendation for chilli onion intercropping system 25 chilli equivalent yield (kg/ha) = yield of onion (kg/ha )× price of onion (tk./kg) price of chilli (tk./kg) methods of chemical analysis soil ph was measured by a combined glass calomel electrode (jackson, 1958). organic carbon was determined by wet oxidation method (walkley and black, 1934). total n was determined by modified kjeldahl method. k, ca and mg were determined by nh4oac extraction method. cu, fe, mn and zn were determined by dtpa extraction followed by aas reading. boron was determined by cacl2 extraction method. phosphorus was determined by bray and kurtz method (acid soils) and s was determined by cah4 (po4)2. h2o extraction followed by turbidimetric method with bacl2. results and discussion chilli the effect of chemical fertilizers on the yield and yield parameters of chilli are summarized in the table 2. green chilli yield and yield attributes like plant height, number of branches plant−1, number of fruits plant-1 and average fruit weight plant-1 of chilli were significantly influenced by different nutrient packages in this study. the significantly highest plant height (69.5 cm) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of onion) which was statistically similar with t5 treatment whereas the lowest plant height (64.0 cm) was obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of onion). that similar to all other treatments except t5 and t6. table 2. yield and yield components of chilli as influenced by different treatment combinations at gazipur during rabi season (pooled data of 3-years) treatments plant height (cm) number of branches plant−1 number of fruits plant−1 average fruit weight plant−1 (g) chilli yield (t ha−1) t1 64.0c 8.5c 130.0d 181.7e 10.10e t2 64.4c 9.3bc 134.6d 204.2d 10.48d t3 65.7c 9.6ab 139.5c 211.4c 10.90c t4 66.5bc 9.6ab 145.3b 217.3b 11.40b t5 69.0ab 10.0ab 157.7a 233.6a 12.15a t6 69.5a 10.2a 159.4a 236.2a 12.18a se (±) 1.38 1.21 2.98 2.80 0.23 cv (%) 6.37 5.83 3.87 3.26 9.21 means followed by same letter (s) do not differ significantly at 5% level of significance. t1= 100% rdcf of chilli + 0% rdcf of onion, t2= 100% rdcf of chilli + 10% rdcf of onion, t3= 100% rdcf of chilli + 20% rdcf of onion, t4= 100% rdcf of chilli + 30% rdcf of onion, t5= 100% rdcf of chilli + 40% rdcf of onion and t6= 100% rdcf of chilli + 50% rdcf of onion number of branches plant−1 positively affected by different fertilizer treatment. significantly the highest number of branches plant−1 (10.2) was obtained from t6 treatment whereas the lowest number of branches plant−1 (8.5) was recorded in t1 treatment. number of fruits plant−1 progressively increases with the increase of inorganic fertilizers. the maximum number of fruits plant−1 (159.4) was obtained from t6 treatment which was statistically similar with t5 treatment while the minimum number of fruits plant−1 (130.0) was obtained from t1 treatment. the significantly highest average fruit weight plant−1 (236.2 g) was obtained from t6 treatment which was statistically similar with t5 and superior to all other treatments. the lowest average fruit weight plant−1 (181.7 gm) was recorded in t1 treatment. 26 farhad et al. yield of chilli progressively increases with the increase of inorganic fertilizers. significantly the highest yield of green chilli (12.18 t ha−1) was obtained from t6 treatment (100% rdcf of chilli + 50% rdcf of onion) which was statistically similar with t5 treatment (100% rdcf of chilli +40% rdcf of onion) and superior to all other treatments. the lowest yield of green chilli (10.10 t ha−1) was observed in t1 treatment (100% rdcf of chilli + 0% rdcf of onion). the result was similar to the findings of farhad et al. (2022) in chill + garlic intercropping system and in maize + potato intercropping system. onion the effect of chemical fertilizers on the yield and yield parameters of onion are summarized in the table 3. the results indicated that all of the yield attributes of onion were significantly influenced by different treatment combinations. the highest plant height (55.4 cm) was obtained from t6 treatment (100% rdcf of chilli +50% rdcf of onion) which was statistically at par with t3 and t4 treatment whereas the lowest plant height (50.3 cm) was obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of onion), also similar with t2 and t3 treatments. table 3. effect of different treatments on the yield and yield attributes of onion at gazipur during rabi season (pooled data of 3-years) treatments plant height (cm) number of leaves plant-1 bulb length (cm) bulb diameter (cm) individual bulb weight (g) bulb yield (t ha-1) t1 50.3b 8.2e 4.37c 4.10d 36.1c 7.44d t2 51.5b 8.5de 4.38c 4.16c 36.4c 7.50d t3 52.1b 8.7cd 4.43bc 4.19c 37.6b 7.77c t4 54.4a 9.1bc 4.48ab 4.25b 38.7ab 7.93b t5 55.3a 9.4ab 4.54a 4.30a 39.5a 8.11a t6 55.4a 9.6a 4.56a 4.32a 39.8a 8.13a se (±) 1.29 1.13 0.08 0.05 0.72 0.06 cv (%) 5.80 8.72 5.81 3.91 4.81 8.12 means followed by same letter (s) do not differ significantly at 5% level of significance. t1= 100% rdcf of chilli + 0% rdcf of onion, t2= 100% rdcf of chilli + 10% rdcf of onion, t3= 100% rdcf of chilli + 20% rdcf of onion, t4= 100% rdcf of chilli + 30% rdcf of onion, t5= 100% rdcf of chilli + 40% rdcf of onion and t6= 100% rdcf of chilli + 50% rdcf of onion the maximum number of leaves plant−1 (9.6) was obtained from t6 treatment which was statistically similar with t5 treatment whereas the minimum number of leaves plant−1 (8.2) was obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of onion). both of bulb length and bulb diameter are progressively increases with the increase of fertilizers. the highest bulb length (4.56 cm) and bulb diameter (4.32 cm) were obtained from t6 treatment (100% rdcf of chilli + 50% rdcf of onion) which was statistically similar with t5 treatment (100% rdcf of chilli + 40% rdcf of onion). the lowest bulb length (4.37 cm) and bulb diameter (4.10 cm) were obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of onion). individual bulb weight and yield of onion progressively increases with the increase of inorganic fertilizers. significantly the highest individual bulb weight (39.8 g) and bulb yield (8.13 t ha−1) of onion were obtained from t6 treatment (100% rdcf of chilli + 50% rdcf of onion) which was statistically similar with t5 treatment (100% rdcf of chilli + 40% rdcf of onion) and superior to all other treatments.the lowest individual bulb weight (36.1 g) and bulb yield (7.44 t ha−1)were obtained from t1 treatment (100% rdcf of chilli + 0% rdcf of onion). chilli equivalent yield chilli equivalent yield (cey) was progressively increased with the increase of inorganic fertilizers. the result showed that t6 provided the highest cey (21.93 t ha−1) that was15.29% higher over t1 (fig. 1). the treatment t5 also gave higher cey (21.88 t ha−1) followed by t4, t3 fertilizer recommendation for chilli onion intercropping system 27 and t2. the higher cey was mainly attributed due to additional yield advantage resulted from fertilizer effect in chill-onion intercropping. the result was similar to the findings of farhad et al. (2022) who observed that there was a trend of increase in cey with the increase of inorganic fertilizer level and the cey was decreased considerably towards lower fertilizer levels in chilli with onion intercropping system. begum et al. (2016) also reported pey increased towards higher fertilizer rates in potato-hybrid maize intercropping system. fig.1. chilli equivalent yield (cey) and % cey increase over t1 in different treatment combinations cost and return analysis cost and return of chilli with onion intercropping have been described in the table 4. among the treatments, the highest net return (430005 tk. ha-1) as well as bcr (4.67) were obtained from t5 treatment (100% rdcf of chilli + 40% rdcf of onion) whereas the lowest net return (364411 tk. ha-1) as well as bcr (4.28) were observed in t1 treatment (100% rdcf of chilli + 0% rdcf of onion). though t6 treatment gave higher yield over all the treatments yet it showed lower bcr compared to t5 treatment due to higher cost involvement for inorganic fertilizer. table 4. cost and return analysis of chilli with onion intercropping system as influenced by different fertilizer treatment combinations at gazipur during rabi season (pooled data of 3-years) treatments yield (t ha-1) chilli equivalent yield (t ha-1) gross return (tk. ha-1) total cost (tk. ha-1) net return (tk. ha-1) benefit cost ratio (bcr) chilli onion t1 10.10 7.44 19.02 475500 111089 364411 4.28 t2 10.48 7.50 19.48 487000 112566 374434 4.32 t3 10.90 7.77 20.22 505500 114042 391458 4.43 t4 11.40 7.93 20.91 522750 115520 407230 4.52 t5 12.15 8.11 21.88 547000 116995 430005 4.67 t6 12.18 8.13 21.93 548250 118472 429778 4.62 input and output price per kg: urea = tk. 16, tsp = tk. 22, mop = tk. 15, gypsum = tk. 12, zinc sulphate =tk.150, boric acid tk. = tk.220, chilli seed =tk.600, onion seed =tk.900, chilli selling price = tk. 25 and onion selling price = tk. 30 28 farhad et al. conclusion from the present study, it may be concluded that treatment package consists of 100% recommended doses chemical fertilizers of chilli along with 40% recommended doses chemical fertilizers of onion is most profitable for chilli with onion intercropping system in the study area (aez-28). references bandyopadhyay, s.k. 1984. nitrogen and water relations in grain sorghum legume intercropping systems. ph. d. dissertation, indian agricultural research institute (iari), new delhi110012, india. begum, a.a., m.s.u. bhuiya, s.m.a. hossain, a. khatun and s.k. das. 2016. effect of fertilizer management on productivity of potato-hybrid maize intercropping system. bangladesh j. agril. res. 41(4): 633-645. begum, s.a., m.s. zaman and a.s.m.m.r. khan. 2015. intercropping of root crops with chilli in charlands of mymensingh. prog. agric. 26: 109-114. farhad, i. s. m., e. jahan, r. sen, m. m. u. chowdhury and s. akhter. 2022. fertilizer recommendation for chill-garlic intercropping system. bangladesh agron. j. 25(1): 7-14. jackson, m.l. 1958. soil chemical analysis. prentice hall inc. engle-wood, cliffs, n.y. launay, m., n. brisson, s. satger, h. hauggaard-nielsen, g. corre-hellou, e. kasynova, r. ruske, e.s. jensen and m.j. gooding. 2009. exploring options for managing strategies for pea-barley intercropping using a modeling approach. eur. j. agron. 31: 85-98. mucheru-muna, m., p. pypers, d. mugendi and b. vanlauwe. 2010. a staggered maize-legume intercrop arrangement robustly increases crop yields and economic returns in the highlands of central kenya. field crops res. 115: 132-139. seran, t.h. and i. brintha. 2010. review on maize-based intercropping. j. agron. 9(3): 135-145. steel, r.g.d. and torrie, a.h. 1960. principles and procedures of statistics with special reference to the biological sciences. mcgraw hill, new york, 187-287. walkley, a. and i.a. black. 1934. an examination of the degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. soil sci. 37: 29-38. bangladesh agron. j. 2024, 27(2): 96-107 contribution of genotype, environment and management components on rice yield and strategy for yield enhancement in fallow-t. aman rice-fallow cropping pattern n. parvin1*, m.a. salam2, m.u. salam3, m.a. kader2, m.a.a. mamun4, b. nessa5 and a.k. hasan2 1rice farming systems division, bangladesh rice research institute, gazipur-1701, bangladesh 2department of agronomy, bangladesh agricultural university, mymensingh-2202, bangladesh 3freelance consultant, 115/3, east bhurulia, joydebpur, gazipur-1700, bangladesh 4agriculture statistic division, bangladesh rice research institute, gazipur-1701, bangladesh 5plant pathology division, bangladesh rice research institute, gazipur-1701, bangladesh *corresponding author, email: nargisrfs@gmail.com (received: 23 june 2025, accepted: 31 july 2025) key words: genotype, environment, management, rice, yield enhancement abstract genotype (g), environment (e) and management (m) form a triangular association in realizing grain yield of t. aman rice. g expresses its yield potential when grown in right e under appropriate m. this study presents additive contribution of these three gem components to grain yield of the crop. this study was undertaken to develop a gem-based framework and use it in prioritizing strategic avenues for enhancement of rice in the fallow-t. aman-fallow cropping system. partitioning of grain yield of rice into g, e and m components was done following standard principle using 4491 research data-points from one decade’s experiments (2010 to 2019) conducted by the bangladesh rice research institute. results showed under the high yield potential varieties, g differences justified 29.5%, e 48.9% and m 21.6% variation in grain yield. the relative contribution of gem components was not static across the years. as time advanced (from 2010), the contribution of g in explaining grain yield was found gradually reducing, whereas the contribution of e and m increasing. in the interrelationship between the three gem components, the contribution of g was almost static and m was negative across e. the yield response specific to g, considering the two prominent rice varieties, br11 and brri dhan49 was very narrow (4.60 to 4.68 t ha−1), whereas e and m was much wider (3.53 t ha−1 respectively). two varieties did not equally respond to all management. furthermore, the grain yield from the same management responded differently to e (both location and year). while e and m are the triggering points for yield improvements in t. aman rice, minimizing yield gap among the e by physical interventions is not a likely option. this study provides three pathways of linking m to yield improvements in t. aman rice management in relation to genotype, location and growing season. hence, it is concluded that for augmenting grain yield of t. aman rice in the present circumstances, prioritizing m specific to g and e is the practical pathway. introduction potential yield (y) of a rice variety is determined by its genetic ability. improved genotype (g) suitable for target environment (e) is the prime requisite for higher productivity (alam et al., 2012). however, yield gap could still exist and productivity could become unstable if appropriate management (m) is not synchronized with g in specific environment. management encompasses practices such as seedling age, planting time, spacing, irrigation, fertilization, pest control and others appropriate. therefore, in realizing the yield potential of a variety in farmers’ field, the contribution of e and m cannot be ignored (anderson, 2010). mailto:nargisrfs@gmail.com 97 parvin et al. it is generally agreed that both breeding and agronomy have contributed to yield advances although the relative contribution of each have varied according to the crop species, variety and e (fischer and wall, 1976; byerlee, 1994). in rainfed wheat, the yield improvement attributed to crop management was quantified as 47% in usa (schmidt, 1984), 67% in victoria, australia (o’brien, 1982), 68 to 71% in western australia (perry and d’antuono, 1989). to enhance and sustain rice yield performance in a target system, such as fallow-t. aman-fallow cropping system (tcs), existing composition of the three ‘yield realizing drivers’ needs to be estimated, so that the strategic pathways can be prioritized. there have been little studies either bangladesh or elsewhere on partitioning and quantifying, the contribution of gem on enhancing rice yield. the contribution of g under farmers existing management practices (femp) in the tcs will measure the robustness of the g in the system. accordingly, the m would need to be designed as the instrument for yield improvement in the tcs. keeping the views in mind, this research explored estimation of the existing composition of gem on rice yield variability and use this information to prioritize strategic avenues for yield enhancement in tcs. materials and methods this analysis accounted for rice yield variability in t. aman season, as a component of tcs. the principle of partitioning grain yield to the three gem components followed the works of salam et al. (2017). data for the analysis altogether 4491 data-points, previously used for meta-analysis in a separate study was used. the data-points comprised of 69 g, 148 e and 38 m. genotype included 43 high yield potential varieties (hyp) and 26 other variety types (aromatic, market demand and photosensitive varieties were 11, 4 and 11 respectively). each e was a combination of a location (administrative district) and year of experimentation. wade et al. (1999), anderson (2010) and macmillan and gulden (2020) have also presented a similar definition of e. each m included a combination of three managements such as i) transplanting time: very early (up to 14 july), early (15-29 july), mid (30 july-13 august), late (14-28 august) and very late (after 28 august); ii) seedling age: younger (≤ 30 days), middle (31-40 days), older (41-50 days) and very older (> 50 days) and iii) hill density (number of hills m−2): standard (≤ 3), high (4-5) and very high (> 5). estimation of partitioning grain yield variability between the three gem components the contribution of gem components was estimated using the following equations: g (% contribution) = g. var. total var. × 100 e (% contribution) = e. var. total var. × 100 m (% contribution) = m. var. total var. × 100 where, g. var. = genetic variance, e. var. = environmental variance and m. var. = management variance for respective number of data-points; total var. = total variance is the sum of g. var., e. var. and m. var. variance was calculated using ‘var’ function of ms-excel (2016). overall relative contribution of the three gem components was estimated for 69 g, 148 e and 38 m using 4491 data-points; and for hyp varieties, 43 g, 145 e and 36 m using 3870 data-points. contribution of genotype, environment and management components on rice yield 98 estimation of annual changes, periodic sensitivity and interrelations in hyps of the three gem components using the data of hyps, the periodic sensitivity of the three gem components was estimated for 10 years (2010 to 2019). for this, g. var., e. var. and m. var. were estimated for individual years of experimentation. the sample size for each set (gem component × year) was as follows (table 1). table 1. the sample size for each set (gem component × year) for individual years, relative contribution of gem components was estimated following the equations. the linear trend of the periodic sensitivity of the three gem components was calculated with the above data through estimated intercept and slope of linear regression equation for respective g, e and m. the level of probability of the liner trends across the 10 years was calculated for each trend. the interrelationships between the three gem components were estimated using the above data (year-by-year contribution of gem components). for this, data on contribution of g and m were regressed separately over e. the level of probability was calculated for each regression line. all the calculation were performed in ms-excel using respective functions. development of gem-based framework for enhancing yield of t. aman rice for enhancing the yield of t. aman rice in the tcs, the assumption was consideration of the hyp genotypes to be the ideal first option. accordingly, the state of performance of two varieties, br11 and brri dhan49 were considered. rice var. br11, released in 1980, is one of the most visible mega-varieties of t. aman rice that bangladesh ever produced. to replace the variety with a newer one, brri dhan49 was released in 2008. six locations (cumilla, gazipur, kushtia, rajshahi, rangpur and satkhira) of three years’ data for rice var. br11 and/or brri dhan49 were considered for this analysis. the available data provided 39 combinations of e, and 24 combinations of m within the es. including 2 g, total available data-points were 273, out of probable 1872 data-points (2 g × 39 e × 24 m). it may be noted that all the matrices (2 g × 39 e × 24 m) were not available according to selection criteria. the 39 es weree1: 2010 cumilla, e2: 2010 rajshahi, e3: 2011 cumilla, e4: 2011 gazipur, e5: 2011 kushtia, e6: 2011 rajshahi, e7: 2012 cumilla, e8: 2012 gazipur, e9: 2012 kushtia, e10: 2012 rajshahi, e11: 2012 rangpur, e12: 2012 satkhira, e13: 2013 gazipur, e14: 2013 kushtia, e15: 2013 rajshahi, e16: 2014 gazipur, e17: 2014 kushtia, e18: 2014 satkhira, e19: 2015 cumilla, e20: 2015 gazipur, e21: 2015 rajshahi, e22: 2015 rangpur, e23: 2015 satkhira, e24: 2016 cumilla, e25: 2016 gazipur, e26: 2016 kushtia, e27: 2016 satkhira, e28: 2017 cumilla, e29: 2017 gazipur, e30: 2017 kushtia, e31: 2017 rajshahi, e32: 2017 satkhira, e33: 2018 cumilla, e34: 2018 kushtia, e35: 2018 rajshahi, e36: 2018 rangpur, e37: 2018 satkhira, e38: 2019 gazipur and e39: 2019 satkhira. year of experimentation gem component g e m 2010 23 9 15 2011 23 16 16 2012 24 19 20 2013 21 27 24 2014 15 10 14 2015 29 24 23 2016 33 12 24 2017 32 8 17 2018 37 14 14 2019 36 6 20 99 parvin et al. the 24 ms werem1: very early younger standard, m2: very early younger high, m3: very early middle high, m4: early younger standard, m5: early younger high, m6: early younger very high, m7: early middle standard, m8: early middle high, m9: early middle very high, m10: mid younger standard, m11: mid younger high, m12: mid younger very high, m13: mid middle standard, m14: mid middle high, m15: mid older standard, m16: late younger standard, m17: late younger high, m18: late younger very high, m19: late middle standard, m20: late middle high, m21: late older standard, m22: very late younger standard, m23: very late younger high, m24: very late older high. the distribution of grain yield was presented in four steps: (i) across all 273 data-points (ii) 2 g, (iii) 39 es and 24 ms. further, mapping of grain yield in the matrix of g (2 varieties) × e (39 environments) × m (24 management combinations) was done in ms-excel. the grain yield difference between br11 and brri dhan49 was calculated under 24 scenarios of m by subtracting the yields between the two varieties. the grain yield variation in the two varieties was measured as standard deviation for the 6 locations and 10 years of experimentation within each of 24 management combinations. results and discussion partitioning grain yield variability between genotype, environment and management the partitioning of grain yield variability between gem components has been presented in the light of meta-data which accounted for diverse genotype, environment (both location and year) and chosen management. farmers’ survey data were not used as it accounted for only one specific location and year. experimental data purposively included varieties having wide range of yield potential; therefore, this data is biased to genotype component of gem and thus not included in this analysis. genotype, environment and management across all varieties figure 1 shows that, g explained the highest of 50.7% of the total variation in grain yield; whereas the proportion of e was 31.6% and that of m was lower (17.7%). fig.1. relative contribution of the gem components (genotype, environment and management) in explaining grain yield variation of t. aman rice. the data included all variety category. a recent g × e-interaction study (akter et al., 2019), shows the attribution of g and e to grain yield of rice as 54.86 and 36.31%, respectively. the findings of the present study are not unexpected, because the experiments were conducted under the scenarios of wide range of genotypes, over 69 local and high yielding types, having varied yield potential. the wider the genetic potential exists, the larger would be the relative share of g in the gem components in contribution of genotype, environment and management components on rice yield 100 achieving yield. conversely, smaller yield variations between genotypes could reduce contribution of g to grain yield as evident from the g × e-interaction study of wade et al. (1999) and bashir et al. (2016). the scenario of larger contribution of g to gem is comparable to an under-developed region where farmers have been predominantly using low yielding local varieties and development program initiated with demonstrating the potential of high yielding varieties. genotype, environment and management across high yield potential varieties under the variety category of hyp compared to whole data, the relative contribution of g to grain yield variation greatly reduced and that of e highly increased (fig. 2). genotypic differences justified 29.5%, whereas the proportion of e in explaining variation of yield performance was 48.9%. the contribution of m was lower (21.6%) than the other two gem components. using hybrid rice varieties in the g × e interaction study, bashir et al. (2016) estimated sole contribution of g and e as 1.03 and 93.8%, respectively, to grain yield. in the similar type of interaction study with rainfed lowland rice varieties, wade et al. (1999) estimated the sole contribution of g and e as 5 and 63%, respectively, to grain yield. it thus appears that the yield enhancement strategy for modern-day agriculture such as for t. aman rice in the cropping system would need due consideration of e and m components of gem. fig. 2. relative contribution of the three gem components (genotype, environment and management) in explaining grain yield variation of t. aman rice. the data included only high yield potential category. annual changes in the relative contribution of genotype, environment and management components across high yield potential varieties the relative contribution of gem components as revealed in the fig. 1 was not static across the years (fig. 3). for example, g explained 47.96% yield variation, followed by e of 31.5% and m of 19.6% in 2010. in 2019, the explained yield variation attributed to the three gem components was very similar (g = 30.6%, e = 33.4% and m = 36.0%). on the contrary in 2017, m explained the absolute major proportion of yield variation (71.4%), have small contribution of g (12.0%) and e (16.36%). in 2018, the contribution of e justified the major yield variation (63.0%), where g contributed to 23.7% and m to 13.3%. as time advanced (from 2010), the relative contribution of g in explaining grain yield was found gradually reducing, whereas the contribution of e and m increasing (fig. 4). quantitatively, the rate of reduction in g component to grain yield variation was 2.11% year−1 101 parvin et al. (p = 0.05), and increase in e and m components was 1.14 (p = 0.25) and 0.96% (p = 0.33) year−1, respectively. this can be explained in two angels. firstly, genetic yield potential of t. aman rice varieties may not be increasing, and/or may have become narrowed between evolving varieties. this has reflected in t. aman rice varieties released by the bangladesh rice research institute (brri). the yield potential of the brri released t. aman rice varieties has not exceeded since br11 (6.0 t ha−1) was released in 1980 except for brri dhan87 (6.5 t ha−1) which was released in 2018 (brri, 2020b). secondly, grain yield variation due to e and/or m has increased. analyses of brri shows that the ‘stability index’ of t. aman rice varieties, accounting for various locations and seasons, has not been constant, rather fluctuating during 2001 to 2020 (brri, 2021). this study has provided an indication that the contribution of e in gem components has been increasing numerically at an estimated rate of 1.14% year−1 (p = 0.25). this reveals that the yield performance of t. aman rice across the es is widening. the pattern of contribution of m in the gem components has been observed similar to e, but in a lower scale (increasing at an estimated rate of 0.97% year−1, p = 0.33). this reveals that all ms are not resulting in similar yield performance of t. aman rice across gs and es. as observed by khatun et al. (2002), the relative effect of seedling age did not similarly respond to rice yield between two es (considering ‘season’ as environment); it was more pronounced in boro than t. aman season with the variety br3. in nepal, shah and yadav (2001) did not observe the highest yield in varieties with same transplanting time, seedling age and season (year of experimentation). in their findings, all varieties yielded better in 1999-2000 than 1998-1999, but in one variety received the highest yield by transplanting 25-day-old seedlings on 7 august, whereas the highest yields in four varieties achieved by transplanting 50-day-old seedlings on 14 july. fig. 3. relative contribution of the three gem components-genotype, environment and management in explaining grain yield variation of t. aman rice. the data included only high yield potential category across 10 years (2010–2019). 0 10 20 30 40 50 60 70 80 90 100 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 relative contribution to grain yield (% of total variance) y ea r g e m contribution of genotype, environment and management components on rice yield 102 fig. 4. the trend in the relative contribution of the three gem components-genotype, environment and management, in explaining grain yield variation of t. aman rice during 10 years. the data included only high yield potential category across 10 years (2010–2019). interrelationship between genotype, environment and management components across hyp varieties interrelationship between the three gem components, presented in fig. 5, shows that across the range of the contribution of e (16.2 to 63.0%), the contribution of g was almost static (r = −0.05, p = 0.45). on the other hand, the relative contribution of e and m was significantly negative (r = −0.76, p = 0.01). results further reveal that the relative contribution of g and m in explaining the grain yield was significantly negative as well (r = −0.61, p = 0.03). as observed in national statistics, comparing three districts (khulna, rajshahi and rangpur), it reveals that the yield variation (expressed as standard deviation) between them was narrow (0.01 t ha−1) during 1995-1996 to 1999-2000 period. in the next 5-year period, it widened to 0.12 t ha−1 and went further (0.15 t ha−1) in the following 5-year period (compiled using bbs, 2018). fig. 5. the interrelationships between the three gem components with respect to relative contribution in explaining grain yield variation of t. aman rice. 103 parvin et al. genotype, environment and management components for two selected high yield potential t. aman rice varieties – yield spread for enhancing the yield of t. aman rice, theoretically, consideration of the hyp gs to be the ideal first option. this study undertook further analysis to layout reality-based pathways for enhancing grain yield of t. aman rice. for this investigation, the performance levels of the varieties br11 and brri dhan49 were taken into account. results presented in fig. 6 indicates yield achieved with the two varieties in 273 scenarios (data-points, g × e × m) in the range of 1.00 to 6.90 t ha−1. however, the yield response specific to g was very narrow (4.60 to 4.68 t ha−1) (fig. 6). the yield response specific to e was much wider than g, in the range of 3.53 to 5.74 t ha−1 (fig. 6), and to m was also wider, in the range of 2.87 to 6.58 t ha−1 (fig. 6). the analysis indicates that g contributed moderately to grain yield variation (29.5%, fig. 2); in addition, the contribution of g had been steadily decreasing in the last decade, 2010– 2019 (fig. 4). reality could be different in rightly attributing g as the driving yield-enhancing component of gem. findings clearly reveal that e and m components of gem are the two reality-based pathways of increasing grain yield of t. aman rice at the current situation in bangladesh. fig. 6. yield spread of two t. aman rice varieties across the dataset and the three gem components. genotype, environment and management components for two selected high yield potential t. aman rice varieties – yield mapping various combinations of e and m largely resulted in similar yield gradient as shown in fig. 7. for example, em combinations e3m4, e10m18 and e36m24 produced the highest yield gradient (4th quarter (>=75%) in the yield range of fig. 7) for g, whereas em combinations e12m2, e27m2 and e37m19 found the second highest yield gradient (3rd quarter (>=50% to <75%) in the yield range of fig. 7) for g. on the other hand, em combinations e5m11, e7m13 and e25m10 showed the second lowest yield gradient (2nd quarter (>=25% to <50%) in the yield range of fig. 7) for g. the same results indicate that, for example, e3, e10 and e36 produced the highest yield gradient, whereas e12, e27 and e37 had the second highest yield gradient. furthermore, e5, e7 and e25 showed the second lowest yield gradient. with respect to m, for example, m4, m18 and m24 produced the highest yield gradient, whereas m2 and m19 had the second highest yield gradient. the second lowest yield gradient was achieved m10, m11 and m13. contribution of genotype, environment and management components on rice yield 104 this study undertook detailed analysis on gem considering two high yield potential t. aman varieties br11 and brri dhan49. br11 is one of the extensively adopted varieties that brri ever released. brri dhan49 has shorter growth duration by 7 days compared to br11; though slightly low yielder than br11 (potentially, by 0.5 t ha−1), it has finer quality grains (nizershail type) (brri, 2020a), and thus considered to be a good potential for wider adoption (brri, 2020). the varieties (designated as g) provided a narrow difference in averaged grain yield (br11 = 4.72 t ha−1; brri dhan49 = 4.60 t ha−1) across 39 es (designated as e combination of location and growing season) and 24 m combinations (designated as m), whereas the differences attributed to e (3.53-5.74 t ha−1, sd = 0.63 t ha−1) and m (2.87-6.58 t ha−1; sd = 0.73 t ha−1) were much wider. as also revealed in the findings that while e explained wide range of grain yield variation (16.2 to 63.0%), the influence of g remained the same (fig. 5). results re-emphasis that for yield improvements in t. aman rice, the scope of engaging g is limited, whereas e and m is wider. fig. 7. mapping of t. aman yield gradient of two varieties (g, br11 (v1) and brri dhan49 (v2)) across 39 environments (e, e1-e39) and 24 managements (m, m1-m24). the notations of 39 environments and 24 management combinations have been referred in materials and methods section. green, yellow, red and black solid circles indicate, respectively, the highest yield gradient (4th quarter, >=75% in the yield range), the second highest yield gradient (3rd quarter, >=50% to <75% in the yield range), the second lowest yield gradient (2nd quarter, >=25% to <50% in the yield range) and lowest yield gradient (1st quarter, <25% in the yield range). grain yield difference between two selected t. aman rice varieties under different management combinations two varieties did not equally respond to all management combinations (fig. 8). for example, br11 better performed than brri dhan49 under m9, m3, m12, m23, m1, m8, m2, m5, m21, m20 and m4. on the other hand, brri dhan49 showed better yield response than br11 under m24, m19, m22 and m6. the managements m7, m10, m11, m13, m14, m15, m16, m17 and m18 were almost equally responsive to both the varieties. this study provides three pathways of linking m to yield improvements in t. aman rice. here, m in relation to g. this study clearly shows that the same m did not produce similar grain yield between gs. the same is also evident from other studies. for example, roy et al. (2003) reported that not all the seven rice varieties responded to respective highest yield to any of the seven transplanting dates undertaken in that study. an experiment with seven t. aman varieties under three transplanting dates (td), observed that statistically highest yield was achieved in three td by three varieties, in td2 and td3 by one variety, only in td2 by two varieties, and only in td1 by one variety. therefore, actions to be find out variety-specific management. 105 parvin et al. fig. 8. grain yield difference in br11 from brri dhan49 under 24 management combinations. ‘m’ denotes for management combination accounting for transplanting time, seedling age and hill density. the notations of 24 management combinations (m1-m24) have been referred in materials and methods section. grain yield variability across locations and years within each management combination the grain yield from the same m responded differently to both location and year (fig. 9). this variation, measured as standard deviation (sd), was not similar across the 24 ms. for example, with respect to location, there was higher sd of 2.20 (t ha−1) with m24, 1.36 (t ha−1) with m12, 1.33 (t ha−1) with m1 and 1.00 (t ha−1) with m8; whereas lower sd of 0.44 (t ha−1) with m17, 0.43 (t ha−1) with m14 and 0.26 (t ha−1) with m6. for example, with respect to year, there was higher sd of 2.20 (t ha−1) with m24, 1.17 (t ha−1) with m22, 1.12 (t ha−1) with m12 and 1.10 (t ha−1) with m2; whereas lower sd of 0.43 (t ha−1) with m10, 0.35 (t ha−1) with m5 and 0.15 (t ha−1) with m18. here m in relation to location, this study further indicates that one m does not produce the same grain yield in different locations. other studies agree with the present observation. for example, using the same level of nitrogen, phosphorus and potassium fertilizer, mamun et al. (2017) observed a yield variation in six locations within madaripur district with brri dhan29 in the range of 4.84-7.08 t ha−1, within faridpur district with brri dhan28 in the range of 6.237.15 t ha−1 and within gopalganj district with brri dhan28 in the range of 6.63-7.31 t ha−1. therefore, actions to be find out location-specific m (location-induced management). thirdly, m in relation to growing season. this study further reveals instability in grain yield due to year-toyear seasonal variability. for example, hossain et al. (2020) recorded significant yield variation (4.22-4.72 t ha−1) in t. aman rice var. brri dhan33 between the four years of experimentation (2010, 2011, 2012 and 2013). in a similar type of experiment, deb et al. (2012) observed yield variation between 4.81 and 7.20 t ha−1 in lowland rice during 2006, 2007, 2008 and 2009 using the same seedling age (14-day old) and var. shiuli. therefore, management options could be worked out towards stabilizing varietal grain yield between growing seasons. -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 m 1 m 2 m 3 m 4 m 5 m 6 m 7 m 8 m 9 m 10 m 11 m 12 m 13 m 14 m 15 m 16 m 17 m 18 m 19 m 20 m 21 m 22 m 23 m 24g ra in y ie ld d if fe re n ce i n b r 11 fr o m b r r i d h an 49 ( t h a-1 ) management contribution of genotype, environment and management components on rice yield 106 fig. 9. grain yield difference, measured as standard deviation, across six locations, and 10 years under 24 management combinations. ‘m’ denotes for management combination accounting for transplanting window, seedling age and hill density. the notations of 24 management combinations (m1-m24) have been referred in materials and methods section. conclusion by analyzing the grain yield attribution during the decade of 2010-2019, particularly on the performance of prominent variety, br11 and brri dhan49, it indicates that for yield improvements in t. aman rice, the scope of engaging g is limited, whereas e and m is wider. however, physical interventions for improving e as such is not a likely option. it is then concluded that under the present scenarios of variety options and environmental diversities, crop management synchronized with g and e would be the practical pathway of enhancing grain yield of t. aman rice. references akter, a., m.j. hasan, m.u. kulsum, l.f. lipi, h. begum, n.m.f. rahman, t. farhat and m.z.i. baki. 2019. stability and adaptability of promising hybrid rice genotypes in different locations of bangladesh. adv. plants. agric. res. 9(1): 35-39. alam, m.s., m.a. baki, m.s. sultana, k.j. ali and m.s. islam. 2012. effect of variety, spacing and number of seedlings per hill on the yield potentials of transplant aman rice. int. j. agri. r. 2(12): 10-15. anderson, w.k. 2010. closing the gap between actual and potential yield of rainfed wheat. the impacts of environment, management and cultivar. field crop res. 116: 14-22. bashir, m., m.t. salaudeen, a. odoba and c.o. azunna. 2016. multilocation yield evaluation of lowland hybrid rice varieties in nigeria. int. j. biol. res. 7(2): 73-80. bbs. 2018. 45 years agriculture statistics of major crops (aus, aman, boro, jute, potato & wheat), bangladesh bureau of statistics (bbs) statistics and informatics division (sid) ministry of planning. government of the people’s republic of bangladesh. brri. 2020a. bangladesh rice research institute, adhunik dhaner chash (modern rice cultivation), 23 th edited. gazipur-1701, bangladesh (in bangla). 107 parvin et al. brri. 2020b. annual research review-xv agricultural economics division. annual research review workshop 2019-20. bangladesh rice research institute, gazipur-1701, bangladesh, pp. 3. brri. 2021. brri annual report 2020-2021, bangladesh rice research institute (brri), gazipur 1701, bangladesh. pp. 234. byerlee d. 1994. technology transfer systems for improved crop management: lessons for the future, in: anderson j. r. (eds), agricultural technology: policy issues for the international community, commonwealth agricultural bureaux international, cambridge, uk, pp. 208-230. deb, d., j. lassig and m. kloft. 2012. a critical assessment of the importance of seedling age in the system of rice intensification (sri) in eastern india. exp. agric. 48 (3): 326-346. fischer, r.a. and p.c. wall. 1976. wheat breeding in mexico and yield increases. aust. inst. agric. sci. 42: 39-148. hossain, k., j. timsina, d.e. johnson, m.k. gathala and t.j. krupnik. 2020. multi-year weed community dynamics and rice yields as influenced by tillage, crop establishment, and weed control: implications for rice-maize rotations in the eastern gangetic plains. crop prot. 138: 105334. khatun, a., m.i.u. mollah, i.h. rashid, m.s. islam and a.h. khan. 2002. seasonal effect of seedling age on the yield of rice. pak. j. biol. sci. 5(1): 40-42. macmillan, k.p. and r.h. gulden. 2020. effect of seeding date, environment and cultivar on soybean seed yield, yield components, and seed quality in the northern great plains. agron. j. 112(3): 1666-1678. mamun, m.a.a., s.a. islam, m.s. islam, a.j. mridha, m.a. saleque. 2017. site-specific nutrient management for irrigated rice in south central region of bangladesh. bangladesh agron. j, 20(2): 1-9. o’brien, l. 1982. victorian wheat yield trends 1898-1977. aust. ins. of agric. sci. 48: 163-168. perry, m.w. and m.f. d’antuono. 1989. yield improvement and associated characteristics of some australian spring wheat cultivars introduced between 1860 and 1982. aust. j. agric. res. 40(3): 457-472. roy, b.c., m.a. hossain and m.a.i. khan. 2003. suitable transplanting time for the modern t. aman rice varieties in tidal non-saline wetland situation of bangladesh. pak. j. biol. sci. 6(7): 661-665. salam, m.u. 2017. improving productivity of mungbean in south-central region of bangladesh, consultancy report, usaid-aesa project, house no.7, road no. 2, banani, dhaka-1213, bangladesh. schmidt, j.w. 1984. genetic contributions to yield gains in wheat. genetic contributions to yield gains in five major crop plants. 7: 89-101. shah, m.l., r. yadav. 2001. response of rice varieties to age of seedlings and transplanting dates. nep. agric. res. 4 & 5: 14-17 wade, l.j., c.g. mclaren, l. quintan, d. harnpichitvitaya, s. rajatasereekul, a.k. sarawgi, a. kumar, h.u. ahmed, a.k. singh, r. rodriguez, j. siopongco, s. sarkarung. 1999. genotype by environment interactions across diverse rainfed lowland rice environments. field crop res. 64: 35-50. crop management bangladesh agron. j. 2025, 28(1): 35-45 growth and yield of chia (salvia hispanica) as influenced by sowing time and row spacing in relation to temperature at different aezs s. s. kakon*, j. a. chowdhury, j. rahman, s. paul, m. a. i. sarker, m. m. alom, m. s. huda and m. n. a. siddique agronomy division, bangladesh agricultural research institute, joydebpur, gazipur 1701, bangladesh *corresponding author, email: kakonbari@gmail.com (received: 16 october 2025, accepted: 21 november 2025) keywords: chia, different aez, leaf area index, row spacing, temperature, total dry matter production, yield abstract a field experiment was conducted at the agronomy research field, gazipur, rars, jamalpur, rars, jashore, rars, burirhat, hars, hathazari, ars, rajbari and ofrd, shyampur of bangladesh agricultural research institute, during rabi season of 2022-23 to study the effect of yield and yield contributing characters of chia seeds as affected by sowing date and spacing at different location. the experiment consisted of four sowing dates viz. (15 nov., 30 nov., 15 dec. and 30 dec.) and two spacing viz. (30 cm × continuous in solid line and 40 cm × continuous in solid line). sowing date showed great influence on total dry matter (tdm) production, leaf area index (lai), yield and yield components of chia. the november sowing produced the maximum tdm and lai at gazipur. these parameters finally contributed to higher seed yield in early planting than later sowing date. the days required for the events of maturity (109 days,108 days,106 days, 112 days, 108 days, 110 days and 108 days at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) was obtained from 15 november sowing. it was also found that 15 november sowing with 30 cm row spacing produced the higher yield (1059.41 kg ha−1, 823.80 kg ha−1, 849.42 kg ha−1, 1037. 94 kg ha−1 and 828.64 kg ha−1 at gazipur, jamalpur, jashore, burirhat and hathazari, respectively) but at rajbari and shyampur produced the highest yield in 15 november sowing with 40 cm row spacing (1273 kg ha−1 and 1327.00 kg ha−1). the results revealed that november sowing produced higher yield might be due to favourable air temperature for growth and development of chia. late sowing after november 30 produced lower yield due to high temperature prevailed at the later growth stage (march) of chia at all locations. results revealed that november sowing with 30 cm × continuous in solid line performed better and with the advancement of sowing dates the temperature increased reduced the grain growth duration and decreased the seed yield. the results revealed that november 15 to november 30 sowing would be the optimum sowing date for chia in relation to air temperature. the temperature co-efficient of chia was estimated at 131.81 kg ha−1 decreased per increasing 1 °c air temperature. effect of temperature on the seed yield of chia was estimated at 74-94 %. introduction chia plant is botanically known as salvia hispanica belong to mint family lamiaceae (cahill, 2004). chia seeds contain high amount of omega-3 fatty acids, proteins, minerals and vitamins therefore they can serve as a potential ingredient for both human food and livestock feeds. agronomic management is one of the most important aspects for the success of any crop with efficient use of all the resources. studies on agronomic management of chia crop are limited as it is a newly introduced crop to bangladesh. for a farmer to get maximum profit from any crop, study about its growth and responses towards inputs is very much essential. as chia being a new crop, different aspects of sowing time and plant population of this crop are to be studied to harness 36 kakon et al. potential yield of this crop. standardization of suitable location specific agronomic practices with respect to spacing and sowing time is essentially required to popularize this crop in bangladesh. the sowing date is an extremely relevant variable, since it determines the duration of the development period of the crop due to variations in environmental temperature and day length to which it is exposed (lobo et al., 2011). it is intolerant to freezing in all development stages (lobo et al., 2011). its minimum and maximum growth temperatures are 11 and 36 °c, respectively, with an optimum range of 16-26 °c (ayerza and coates, 2009). it is considered to be a short-day plant with a threshold of 12-13 h (busilacchi et al., 2013), and as such, its period of growth and fruiting depend on the latitude where it grows. temperature is the single most important climatic factor that affects the growth and development of crop plant (mian et al., 2013). it also influences the other different physiological process of the crop plant. temperature affects root and shoot growth, nutrient uptake, water absorption, photosynthesis, respiration, transpiration, translocation of photosynthate and other metabolic functions in the plant system (ali and sarker, 2016). some studies have shown that the best row spacing range for the culture would be between 30 and 50 cm, with an amount of 5 kilograms of seed per hectare (ayerza and coates, 2011). appropriate sowing time and row spacing are very effective to increase yield of chia. but information under this aspect is unavailable in bangladesh condition. the objective of this study was to determine the effect of climatic conditions in different regions on the growth and yield of chia in different regions. this study also proposes to determine the most promising sowing date and row spacing in terms of growth and yield in chia in the different study areas. materials and methods a field experiment was conducted at the agronomy research field, gazipur, jamalpur rars, jashore rars, burirhat rars, hathazari rars, rajbari ars and ofrd shyampur of bangladesh agricultural research institute, during rabi season of 2022-23. gazipur the experimental site was located at chhiata series under agro-ecological zone-28 (aez28) latitude 23°59 n and longitude 90°24 e. the meteorological data of the experimental site revealed that the highest temperature prevails in march-april and the lowest in december to january. maximum rainfall was received during the months of march. the crop received 133 mm rain showers from november to march in 2022-23 years. the average maximum temperature (32.08 °c) was found in the month of march during the crop growing season (fig. 1 and fig. 2) and minimum (12.77 °c) temperature in the month of january during the crop growing season. jamalpur it is a city of 2031.98 km2 with a population density of 1200 km−2. the warmer weather started in march (35 °c). the coldest month (7.0 °c) is january. the heavy rainfall from may to september ranges from 318 to 436 mm. wheat, maize, potato, tomato, mustard, eggplant, bitter gourd, cauliflower, and other vegetables are cultivated in this area during the arid season (fig. 1 and fig. 2). https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/eggplants https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/momordica-charantia https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/momordica-charantia https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cauliflower growth and yield of chia as influenced by sowing time and row spacing at different aezs 37 fig. 1. weekly maximum air temperature of gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur during crop growing period in 2022-2023 jashore the area of the city is 2,606.94 km2 and it has a population of approximately 2,98,000. the hottest month is april (35.6 °c); however, warmer weather commences in march (33 °c) and remains at 30 °c until november. december and january are the coldest months, with a minimum average temperature of 11–12 °c. this region occupies most of the country's dry zone where the annual rainfall is the lowest. the maximum amount of rainfall is 304 mm, which occurs during july. beans, cabbage, cauliflower, radish, spinach and gourd are cultivated in this region throughout the dry season (fig. 1 and fig. 2). fig. 2. weekly minimum air temperature of gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur during crop growing period in 2022-2023 hathazari it is located at latitude 22.50° n and longitude 91.80° e. the primary crops grown in the area include rice, wheat, maize, pulses and oilseeds. the maximum temperature range 25-37 °c and the minimum temperature range 10-21°c. the annual average rainfall 2590 mm. the https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/gourd 38 kakon et al. average maximum (35.08 °c) was found in the month of march during the crop growing season (fig. 1) and minimum (8.4 °c) temperature in the month of january during the crop growing season (fig. 1 and fig. 2). burirhat it is located at latitude 26.70° n and longitude 89.00° e. the primary crops grown in the area include rice (particularly t. aman and boro) vegetables pulse, jute and spices crop. the maximum temperature range 25-37 °c and the minimum temperature range 8-12 °c. the average maximum temperature (33.08 °c) was found in the month of march during the crop growing season and minimum (8.4 °c) temperature in the month of january during the crop growing season (fig. 1 and fig. 2). rajbari a district in bangladesh, has an area of 1,118.80 square kilometers and a population of 1,189,818 according to the 2022 census. the main crops cultivated in this area are rice, jute, wheat, onion, potato and mustard. the warmer weather started in march (35 °c) and continued until october (31.5 °c). the hottest month is april (32.4 °c). the coldest month (6.5 °c) is january (fig. 1 and fig. 2). shyampur it is situated within the barind tract 23 m above sea level. the area of this metropolis is 120.98 km2. the average maximum temperature is slightly high in this region, starting in march at 33 °c and continuing to increase until october (∼32 °c). during the pre-monsoon and monsoon seasons (march–september), shyampur receives an average of 24.8–106.4 mm of rain, with july having the highest total of 321 mm. the cultivation of cauliflower, cabbage, radish, carrot, beet, turnip, tomato, green spinach and red spinach is predominantly carried out in this region during the dry season.the experiment consisted of four sowing dates viz. (15 nov., 30 nov., 15 dec. and 30 dec.) and two spacing viz. (30 cm × continuous in solid line and 40 cm × continuous in solid line) were used in the study. there were 8 treatment combinations as follows: d1×s1, d1×s2, d2×s1, d2×s2, d3×s1, d3×s2, d4×s1 and d4×s2. the experiment was laid out in a rcbd design with three replications. the unit plot size was 3.6 m × 3.0 m. the crop was fertilized with 60-1530-5 n-p-k-s kg ha−1, respectively (karim et al., 2015). half of n and full doses of other fertilizers were applied at the time of final land preparation and the rest urea was top dressed 35 days after sowing (das). seeds were treated with vitavax. hand weeding was done at 25 das. data on yield and yield contributing characters were taken in all locations and growth parameters like leaf area and dry matter accumulation were measured at different growth stages in gazipur location. to record dry matter weight and leaf area, five plants were sampled at 30, 45, 60, 75 and 90 days after emergence (dae) and at harvest. dry weight of the samples was taken after drying at 80 °c in an oven for 72 h. leaf area was measured by an automatic leaf area meter (l13100 c, l1cor, usa). the crop was harvested on1 march to 4 april 2023 in gazipur, 2nd march to 5 april 2023 in jashore, 7 march to 8 april 2023 and burirhat, 2 march to 5 april 2023 in jamalpur, 5 march to 7 april in shyampur, rajshahi, 2 march to 3 april 2023 in rajbari and 2 march to 5 april 2023 in hathazari. the yield component data was collected from randomly selected ten plants prior to harvest from each plot. at harvest, the yield data was recorded plot wise. data were analyzed statistically and means were compared using lsd test at 5% level of significance. results and discussion days for development events the numbers of days required for different development events of chia are presented in table 1. all the development events varied on sowing dates. chia crop was differed for the events growth and yield of chia as influenced by sowing time and row spacing at different aezs 39 of 50% flowering and maturity. the days required for 50% flowering was differed by sowing time in chia crop. the highest duration for 50% flowering was recorded in 15 november (71 days, 67 days, 64 days, 72 days, 67 days, 69 days and 67 days at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) sowing. table 1. crop development events, mean temperature and crop duration of chia seed as affected by sowing date and row spacing during rabi season of 2022-2023 at different locations treatments duration (days) mean air temperature (°c) days to 50% flowering days to 50% flowering gaz. jam. jas. bur. hat. raj. shyam. gaz. jam. jas. bur. hat. raj. shyam. d1 ×s1 71 67 64 72 67 69 67 21.00 19.43 21.66 19.82 24.90 19.22 18.98 d1 ×s2 71 67 64 72 67 69 67 d2 ×s1 65 62 57 70 62 65 62 20.29 18.72 21.07 19.08 22.48 18.56 18.88 d2×s2 65 62 57 70 62 65 62 d3 ×s1 59 59 54 67 59 61 59 19.71 18.20 20.86 18.96 21.34 18.03 18.46 d3 ×s2 59 59 54 67 59 61 59 d4 ×s1 57 55 50 65 55 58 57 20.44 18.55 21.87 19.87 21.06 18.67 18.74 d4×s2 57 55 50 65 55 58 57 the second highest duration for 50% flowering was recorded in 30 november sowing but all sowing date prevailed lower mean air temperature during flowering stage except hathazari. on the other hand, 30 december sowing time took minimum days for 50% flowering (57 days, 55 days, 50 days,65 days, 55 days, 52 days and 57 days at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively). highest crop growth duration was recorded (109 days, 108 days, 106 days, 112 days, 108 days, 110 days and 110 days at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) in 15 november sowing due to prevailing lower mean air temperature (21.58 °c, 19.89 °c, 22.50 °c, 20.61 °c, 23.57 °c, 19.94 °c and 20.45 °c at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) (table 2). table 2. crop development events, mean temperature and crop duration of chia seed as affected by sowing date and row spacing during rabi season of 2022-2023 at different locations treatments duration (days) mean air temperature (°c) days to harvest days to harvest gaz. jam. jas. bur. hat. raj. shyam. gaz. jam. jas. bur. hat. raj. shyam. d1 × s1 109 108 106 112 108 110 110 21.58 19.89 22.50 20.61 23.57 19.94 20.45 d1 × s2 109 108 106 112 108 110 110 d2 × s1 106 104 104 108 107 106 108 21.71 20.06 22.95 20.68 22.95 19.76 20.78 d2 × s2 106 104 105 108 107 106 108 d3 × s1 103 100 100 101 99 103 102 21.99 20.45 23.31 20.83 22.87 20.45 21.10 d3 × s2 103 100 100 101 99 103 102 d4 × s1 98 97 97 99 97 100 96 22.72 21.38 24.29 22.04 23.68 20.84 21.94 d4 × s2 98 97 97 99 97 100 96 here, d1×s1=15nov×30cm, d1×s2=15nov×40cm, d2×s1=30nov×30cm, d2×s2=30nov×40cm, d3×s1=15dec.×30cm, d3×s2=15dec.×40cm, d3×s1=30dec.×30cm, d3×s2=30dec.×40cm the second highest crop growth duration was recorded in 30 november sowing in all locations. november sown crop prevailed lower mean air temperature throughout the growing 40 kakon et al. period. the minimum crop growth duration (98, 97, 97, 99, 97, 100 and 96 days at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) was recorded in 30 december sowing due to prevailing higher mean air temperature (22.72, 21.38, 24.29, 22.04, 23.68, 20.84 and 21.94 °c at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively ).the reasons for variation in growth duration might be due to increased day and night temperature at later sowing (table 1 and table 2). similar results also have been reported by ali and sarker (2016). leaf area index the leaf area index plays a crucial role in all crop plants because optimum leaf area was required for maximum light interception which results in better photosynthesis. the highest leaf area recorded with the november sowing might had increased due to the presence of more favorable weather conditions for the plant’s vegetative growth. it is influenced by genotype and plant population (murphy et al., 1996). the lai was influenced by different sowing dates over time (fig. 1) in 2022-23. fig. 3. leaf area index of chia as influenced by sowing date and row spacing during rabi season of 2022-23. here, d1×s1=15nov×30cm, d1×s2=15nov×40cm, d2×s1=30nov×30cm, d2×s2=30nov×40cm, d3×s1=15dec×30cm, d3×s2=15dec× 40cm in this study, the variation in plant population greatly influenced lai. lai increased with the increase in plant population. leaf area index increased up to 60 dae and there after it decrease in all the treatments. the higher lai was recorded in15 november sowing date with 30 cm × continuous sowing row spacing followed by 30 november sowing date with 30 cm × continuous sowing row spacing in all growth period. maximum lai (3.28) was recorded at 60 dae in 15 november sowing date with 30 cm × continuous sowing (d1s1) treatment followed by d2s1 treatment. leaf area index was lower with 40 cm × continuous sowing in all the sowing dates. the result of the present study was also supported by (karim et al., 2015). effect of sowing date and row spacing on total dry matter (tdm) production the pattern of tdm accumulation in chia over time was influenced by different sowing dates and row spacing (fig.4). the tdm of chia increased slowly up to 45 dae when the crop sown on 15 and 30 november. after 45 dae dry matter accumulation rate increased rapidly up to harvest. among the sowing dates, 15 november sowing with 30 cm × continuous seeding row growth and yield of chia as influenced by sowing time and row spacing at different aezs 41 spacing showed the highest tdm (1153 g m−2) at 90 dae and it was higher throughout the growing period except at 30 and 45 dae followed by 30 november sowing with 30 cm × continuous seeding and it was higher than 15-30 december sowing throughout the growing period in 2022-23. the crop sown on november got longer duration might be due to favorable temperature for growth and development as compared to other sowing dates and produced the maximum tdm. the results are in agreement with the findings of karim et al. (2015) stated that sowing dates had significant difference on dry matter production. the lowest tdm was observed in 30 december sowing at all over the growing period. moosavi et al. (2012) reported that delay in sowing decreased significantly the plant height, leaf area index, total fresh and dry yield in maize. significant differences in plant height of two kenaf genotypes were found between the early and late plantings, throughout the growing period (danalatos and archontoulis, 2004). fig.4.total dry matter production of chia as influenced by sowing date and row spacing during rabi season of 2022-23. here, d1×s1=15nov.×30cm, d1×s2=15nov.×40cm, d2×s1=30nov.×30cm, d2×s2=30nov.×40cm, d3×s1=15dec.×30cm, d3×s2=15dec.×40cm, d3×s1=30dec.×30cm, d3×s2=30dec.×40cm yield and yield components number of plant population−2, plant height, yield and yield contributing characters of chia were significantly influenced by sowing date and row spacing in all locations (table 3). table 3. plant population, and plant height at harvest of chia influenced by spacing and sowing dates treatments plant population (m−2) plant height (cm) gaz. jam. jas. bur. hat. raj. shyam gaz. jam. jas. bur. hat. raj. shyam. d1 × s1 92 78 79 83 74 119 78 129.33 146.07 106.73 149.53 108.73 98.86 150.7 d1 × s2 86 69 67 77 67 101 67 117.33 147.33 112.93 140.07 109.93 98.06 153.3 d2 × s1 98 81 73 80 70 96 74 123.20 139.9 108.8 146.93 107.28 96.93 161.9 d2 × s2 85 79 69 76 66 84 65 112.37 132.07 109.93 143.73 108.93 95.83 159.9 d3 × s1 96 85 79 79 71 94 72 96.00 128.27 98.4 148.00 103.14 94.13 162.9 d3 × s2 83 69 68 69 69 84 64 85.56 115.43 80.33 154.20 104.33 92.86 168.33 d4 × s1 98 77 76 75 69 90 76 83.37 106.2 88.47 133.53 88.47 90.33 153.8 d4 × s2 83 71 67 67 62 77 64 79.93 97.33 106.73 137.00 96.73 88.56 143.5 lsd (0.05) 4.07 10.10 14.10 5.40 3.23 6.9 3.13 3.42 11.7 13.80 ns 13.8 13.07 3.69 cv% 3.89 3.20 10.66 3.66 4.66 10.38 3.66 3.82 5.29 7.77 6.46 7.77 7.90 10.12 highest (92, 78, 79, 83, 74, 119 and 78) no. of plants were recorded in 15 november sowing with 30 cm row spacing and the lowest was recorded in 30 december sowing with 40 cm 42 kakon et al. row spacing in all locations. plant height at harvest varied significantly among sowing date and row spacing in all locations have been presented in table 3. the highest (129.33 cm, 146.07 cm, 106.73 cm, 149.53 cm, 108.73 cm, 98.86 cm and 150.7 cm at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) plant height was recorded from 15 november sowing with 30 cm row spacing followed by 30 november with 30 cm row spacing in all locations and the lowest from 30 december sowing with 40 cm row spacing all locations. significantly the highest number inflorescences plant−1 (13, 17, 15, 15, 12, 12 and 14 at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) was obtained from 15 november sowing with 40 cm row spacing whereas 30 december sowing with 40 cm row spacing significantly the lowest number of inflorescences plant−1 in all locations (table 4). the maximum number of seed inflorescences−1 (414, 409, 317, 374, 411 and 442 at gazipur, jamalpur, jashore, burirhat, hathazari and rajbari, respectively) was recorded in 15 november sowing with 40 cm row spacing but at shyampur, maximum number of seed inflorescences−1 (442) was recorded in 15 november sowing with 30 cm row spacing whereas the lowest number of seed inflorescences−1 was recorded in 30 december sowing with 40 cm row spacing in all locations. table 4. number of inflorescence and seeds inflorescence−1 treatments inflorescence plant−1 seeds inflorescence−1 gaz. jam. jas. bur. hat. raj. shyam. gaz. jam. jas. bur. hat. raj. shyam. d1 × s1 13 14 14 13 12 14 12 381 358 274 395 360 379 442 d1 × s2 15 17 17 15 13 15 13 414 409 317 374 411 442 396 d2 × s1 13 13 13 14 12 13 13 359 265 257 342 347 389 397 d2× s2 15 16 15 15 13 14 13 370 274 305 377 368 423 422 d3 × s1 10 6 7 12 8 13 15 307 191 231 366 303 377 187 d3 × s2 12 7 9 13 9 12 17 325 187 281 352 329 390 173 d4 × s1 9 4 5 9 6 12 18 241 91 215 238 242 350 198 d4× s2 9 6 7 9 8 11 21 250 92 254 250 261 365 95 lsd (0.05) 0.63 0.61 0.61 0.93 0.39 2.11 2.76 23.78 65.5 23.5 51.98 20.89 71.60 37.2 cv% 4.09 3.37 3.26 4.23 3.32 9.27 10.46 4.09 3.01 5.24 5.13 3.74 9.42 7.35 the highest 1000-grain weight (1.27, 1.04, 1.23, 1.24, 1.48, 1.27 and 1.3 g at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari and shyampur, respectively) was recorded in15 november sowing with 40 cm row spacing and the lowest grain weight was recorded in 30 december with 30 cm row spacing in all locations (table 5). there are reports of thousand seed weight ranging from 1.21 grams to 1.31 grams, in field trials in argentina (rovati et al., 2012). grain yield of a crop is the expression of combined effects of various yield components. all the yield components contributed to the final yield. significantly the highest yield (1059.41, 823.80, 849.42, 1037.94 and 828.64 kg ha−1 at gazipur, jamalpur, jashore, burirhat and hathazari, respectively) was obtained from 15 november sowing with 30 cm row spacing which was statistically similar to 30 november with 30 cm row spacing but at rajbari and shyampur produced the highest yield in 15 november sowing with 40 cm row spacing (1273 and 1327.00 kg ha−1). the lowest yield (359.57, 448, 420.74, 633.92, 333.43, 273.67 and 508.33 kg ha−1 at gazipur, jamalpur, jashore, burirhat, hathazari, rajbari was shyampur in 30 december sowing with 40 cm row spacing. all the wider row spacing yielded lower at december 30 sowing might be due to high temperature at reproductive stage which caused lower number of inflorescences plant−1, seed inflorescences−1 and lower seed size. these findings agree with wojahn et al. (2018) and busilachi et al. (2013). this difference in seed yield among different sowing time difference in adaptation to high temperature, which reduced the yield drastically due to its detrimental effects on metabolism and duration of phonological phases (ali and sarker, 2016). the present study revealed that more tdm production in 15 november sowing with 30 cm row spacing and long growth and yield of chia as influenced by sowing time and row spacing at different aezs 43 crop growth duration increased inflorescences size and seed number per inflorescences that ultimately increased the seed yield. on the other hand, the lowest grain yield was observed in 30 december sowing. it was founded that 30 december sowing crop received cool temperature at early growth stage which produced higher flower and higher temperature at reproductive phase that hastened maturity and reduced tdm production and translocation of less dry matter to the reproductive organ (grain). yield of chia was found more or less high at gazipur, burirhat, shyampur and rajbari than jashore, hathazari and jamalpur locations. it might be due to maximum and minimum temperature prevailed during chia growing period at gazipur, burirhat, shyampur and rajbari was lower than jashore, hathazari and jamalpur location (fig.1 and 2). similar findings were also obtained by ayerza and coates (2005). ayerza and coates (2007) also reported that the yield of chia 2253 kg ha−1 and the growth period required 135 days in yungas ecosystem of tropical argentina. table 5. weight of thousand seeds and yield (kg ha−1) treatments 1000-seed weight (g) yield (kg ha−1) gaz. jam. jas. bur. hat. raj. shyam. gaz. jam. jas. bur. hat. raj. shyam. d1 × s1 1.24 1.02 1.20 1.23 1.46 1.10 1.13 1059.41 823.80 849.42 1037.94 828.64 1010.00 1280.33 d1 × s2 1.27 1.04 1.23 1.24 1.48 1.27 1.30 1001.92 762.40 772.36 998.16 767.79 1273.00 1327 d2 × s1 1.21 0.87 1.24 1.21 1.45 1.17 1.14 1010.49 815.73 788.90 1000.2 799.55 1010.67 1132 d2 × s2 1.23 0.91 1.22 1.20 1.46 1.21 1.07 895.68 725.33 732.23 973.43 678.56 893.33 1293.66 d3 × s1 1.18 0.79 1.25 1.17 1.45 1.07 0.99 684.72 686.13 622.12 763.72 648.18 525.00 726.66 d3 × s2 1.20 0.93 1.26 1.17 1.46 1.13 0.77 621.94 566.40 573.30 768.5 542.71 501.00 673.33 d4 × s1 0.82 0.90 1.17 1.14 1.44 0.87 0.79 436.32 557.87 560.03 675.29 438.89 318.00 510 d4 × s2 0.84 0.89 1.19 1.15 1.40 1.04 1.15 359.57 448.00 420.74 633.92 333.43 273.67 508.33 lsd (0.05) 0.05 0.12 0.04 ns ns 0.97 0.14 63.32 45.11 50.56 59.29 35.68 16.60 78.84 cv% 3.18 7.39 4.56 4.12 5.44 4.83 7.76 4.72 3.83 4.34 3.95 3.24 4.82 4.83 here, d1×s1=15nov×30cm, d1×s2=15nov×40cm, d2×s1=30nov×30cm, d2×s2=30nov×40cm, d3×s1=15dec×30cm, d3×s2=15dec×40cm, d3×s1=30dec×30cm, d3×s2=30dec×40cm relationship between grain yield and air temperature there was a negative linear relationship between yield (kg ha−1) of chia and air temperature of all locations has been shown in fig. 5. at gazipur, the regression line (y= −191.83x+4984, r2=0.94) indicated that the regression of co-efficient (x) was 191. this expressed that yield of chia would decrease at the rate of 191 kg ha−1 per increase of 10c air temperature. the coefficient of determination (r2=0.94) value indicated that air temperature had 94% effect on yield of chia. similar expression was made by the regression line (y= −98.88x+2694, r2 =0.90) at jamalpur, (y= −84.90x + 2640, r2=0.96) at jashore, (y= −130.90x+3710, r2 =0.82) at hathazari, (y= −57.12x + 2058.1, r2=0.76) at burirhat, (y= −224.9x + 5280, r2=0.74) at rajbari and (y= −134.26x + 3762.4, r2=0.91) at shyampur. the results revealed that increasing temperature decreases the yield of chia. similar results have also been described by mian et al. (2016). temperature co-efficient (average of seven locations) of chia was estimated at 131.81 kg ha−1 decreased per increasing 1 °c air temperature. effect of temperature on the grain yield of chia was estimated at 74-94%. 44 kakon et al. fig.5. functional relationship between mean air temperature and grain yield of chia conclusion results revealed that november 15 to november 30 sowing would be the optimum sowing date for chia in relation to air temperature. temperature co-efficient of chia was estimated at 131.81 kg ha−1 decreased per increasing 1 0c air temperature and the effect of temperature on grain yield of wheat was estimated at 74-94%. references ali, m.z. and m.a.i. sarker. 2016. effect of sowing time-based temperature variation on growth, yield and seed quality of gardenpea. in: unfavourable ecosystem. crop production under high temperature and drought stress. agronomy division, bangladesh agril. res. int. gazipur 1701. pp. 1-7. ayerza, r. and w. coates. 2005. effect of ground chia seed and chia oil on plasma total cholesterol, ldl, hdl, triglyceride content and fatty acid composition when fed to rats. nutr. res. 11: 995–1003. ayerza, r. and w. coates. 2007. seed yield, oil content and fatty acid composition of three botanical sources of ω-3 fatty acid planted in the yungas ecosystem of tropical argentina. trop. sci. 47: 183–187. y = −191.83x + 4985.7 r² = 0.9472y ie ld ( k g h a− 1 ) mean air temperature (°c) gazipur y = −84.907x + 2640 r² = 0.9638y ie ld ( k g h a− 1 ) mean air temperature (°c) jashore y = −130.99x + 3710.2 r² = 0.8242y ie ld ( k g h a− 1 ) mean air temperature (°c) hathazari y = −57.12x + 2058.1 r² = 0.7637y ie ld ( k g h a− 1 ) mean air temperature (°c) burirhat y = −224.91x + 5280.8 r² = 0.7413 y ie ld ( k g h a− 1 ) mean air temperature (°c) rajbari y = 134.2x + 3762. 0 200 400 600 800 1000 1200 20 20.5 21 21.5 22 yield (kg/ha) mean air temperature( 0 c) shyampur growth and yield of chia as influenced by sowing time and row spacing at different aezs 45 ayerza, r. and w. coates. 2011. protein content, oil content and fatty acid profiles as potential criteria to determine the origin of commercially grown chia (salvia hispanical.). ind. crops prod. 34(2): 13661371. busilacchi, h., m. bueno, c. severin, o.d. sapio, m. quiroga and v. flores. 2013. evaluation of salvia hispanica l. cultivated in southern santa fe (republic of argentina). cult. trop. 34(4): 55–59. cahill, j.p. 2004. genetic diversity among varieties of chia (salvia hispanica l.). genet. resour. crop. evol. 51: 773-778. danalatos, n.g. and s.v. archontoulis. 2004. potential growth and biomass productivity of kenaf under central greek conditions: ii. the influence of variety, sowing time and plant density, biomass for energy, industryand climate protection. proceedings of the 2nd world biomass conference, 10-14 may, rome, italy. pp.319–322. karim, m.m., m. ashrafuzzaman and m.a. hossain. 2015. effect of planting time on the growth and yield of chia (salvia hispanica l.). asian j. med. biol. res. 1(3): 502-507. lobo, r.l., m.g. alcocer, f.j. fuentes, w.a. rodriguez, m. morandini and m.r. devani. 2011. development of chia cultivation in tucumán, argentine republic. avd. agroind. 32(4): 27-30. mian, m.a.k., m.r. islam, j. hossain and m.s. alam. 2013. assessing agro climatological model of summer mungbean. in: international conference on crop management in changing climate. univ. faisalabad. pakistan. p. 135. mian, m.a.k., m.r. islam, j. hossain and m.a. aziz. 2016. grain growth of wheat under prevailing air temperature. bangladesh agron. j. 19(2): 79-85. moosavi s.g., m.j. seghatoleslami and a. moazeni. 2012. effect of planting date and plant density on morphological traits, lai and forage corn (sc. 370) yield in second cultivation. intl. res. j. appl. basic. sci. 3: 57–63. murphy, s.d., y. yakubu, s.f. weise and c.j. swanton. 1996. effect of planting patterns and inter row cultivation on competition between corn and late emerging weeds. weed sci. 44: 865-870. rovati, a., e. escobar and c. prado. 2012. particularities of chia seed (salvia hispanica l.). adv. agroind. 33(3): 39-43. wojahn, r.e., r.p. bortolotto, j.f. zamberlan, j. koeender, j.l. tragnago, j.n. camera, m.p.b. pasini, r.f.s. salazar and f. damiani. 2018. agronomic feasibility of growing chia in northernwestern rio grande do sul. holos. 3: 112-122. blank page bangladesh agron. j. 2024, 27(2): 70-77 effect of plant spacing and leaf clipping on growth and yield of rice m.l. rahman1, s.a. mim2, o.a. ria3, u.k. sabiha3 and m.m. alam2* 1farm management wing, sher-e-bangla agricultural university, dhaka-1207, bangladesh. 2department of agronomy, faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh. 3department of agricultural botany, faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh. *corresponding author, email: shamim1983@yahoo.com (received: 14 april 2025, accepted: 30 june 2025) keywords: leaf cutting, spacing, source-sink relationship, yield attributes, harvest index abstract leaf cutting and spacing plays pivotal role in growth, yield and yield attributing parameters in rice cultivation by reducing different environmental stresses. to assess the effect of leaf cutting and spacing on plant growth and yield, an experiment was conducted with brri released aman var. brri dhan62. the experiment consisted of two factors where spacing for the experiment were s1= 30 × 15 cm2, s2= 30 × 20 cm2, s3= 30 × 25 cm2 and the leaf cutting were t0= no leaf cutting, t1= cutting of 1st basal leaf, t2= cutting of 2nd basal leaf, t3= cutting of 3rd basal leaf. the experiment was conducted with randomized complete block design (rcbd) with 4 replications. results revealed that there was statistically no change in plant height, flag leaf width and length, panicle length, 1000-grain weight, filled grain panicle−1, and straw yield hill−1 at different spacing, leaf cutting, and their combination treatments. regarding growth and yield parameters, the highest number of effective tillers hill−1 was found in combination t1 × s3, which was 50% greater compared to control plants. total tillers hill−1 was found higher in combination t3 × s3, which was 39% higher than the control plants. unfilled grain panicle−1 was found higher in combination t0 × s1, which was 75% higher than the lowest unfilled grain in t0 × s2, this indicates that even a minimal change in spacing can significantly impact yield attributes. harvest index (hi) was found greater in combination t2 × s2, which was 15% higher than the control. the lowest number of filled grain panicle−1 was spotted at t3 × s3 combination indicating that with higher leaf cutting and spacing filled grain number reduced. the growth, yield and yield-contributing parameters showed the best results in 30 × 20 cm2 spacing in combination with cutting of 2nd basal leaf. introduction investigating the alternate agronomic options for increasing crop growth and development specially for rice cultivation by reducing different environmental stresses is important. as rice takes 60-70 days for vegetative growth thus leaf clipping plays a beneficial role in regulating photosynthesis as well as carbohydrate segmentation. as leaves act as a source and sink tissue, thus yield serves as a cumulative result of both source and sink strength for photo-assimilates and nutrients as source strength for photo-assimilates which is dominated by both rate of photo-assimilate remobilization from source tissues and average photosynthetic rate thus leaf clipping has a crucial role on overall photosynthesis and production processes (smith et al., 2018). therefore, exploring leaf clipping effect on source-sink relationship is significant to improve yield of crops. mazur et al. (2019) reported that the efficiency of photosynthetic activity and productivity of a plant largely depends on the extent of photosynthetic surfaces of a plant, thus leaves have a notable effect on the yield of the plants. 71 rahman et al. appropriate plant spacing plays a pivotal role on crop growth, physiology and yield of agronomic crops including rice. the more robust the plants are, the greater the tiller numbers are produced under outspread spacing that enhance photosynthetic potentiality as well as feeding area of soil. rice (oryza sativa l.) is one of the important cereal crops globally apart from its use as the cereal, fodder production has become famous for its income generative and employment source in most of the areas of bangladesh specially livestock potential area while production of rice is decreasing gradually with growing population (islam et al., 2017). therefore, appropriate measurements need to be taken to increase the yield per unit area by adopting the modern and improved technologies. therefore, this study was performed to find out the interaction between spacing and leaf cutting of rice for providing more biomass and regulating both growth and yield. materials and methods experimental site and design the experiment was conducted at the experimental field of sher-e-bangla agricultural university, dhaka under the agro-ecological zone of madhupur tract, aez-28 during the period from july to december 2018. the experimental site is geographically situated at 23 77ʹ n latitude and 90 33ʹ e longitude at an altitude of 8.6 meters above sea level under the subtropical climate. the experiment was laid out in a randomized complete block design (rcbd) with 4 replications. the high yielding rice variety of brri dhan62 was used as planting material the spacing of the experiment were (3): s1= 30 × 15 cm2, s2= 30 × 20 cm2, s3= 30 × 25 cm2 and the leaf cutting were (4): t0= no leaf cutting, t1= cutting of 1st basal l leaf, t2= cutting of 2nd basal leaf and t3= cutting of 3rd basal leaf. fertilizers and manure were used for crop cultivation in accordance with the recommendations of fertilizer recommendation guide. seeds were planted in a seedbed for later transplantation into the main field. weeds and stubble were removed, leaving a well-prepared and suitable field for seedling transplantation. after 3 weeks seedlings were transplanted. all intercultural operations were practiced properly. leaf cutting was done at 30 days after transplanting (dat) when the plant had 5 leaves. measurement of growth parameters the height of plant was measured at the time of harvest for all the entries on 10 randomly selected hill from the middle rows. the height was measured from the base of the plant to the tip of the longest leaf or tip of the longest ear head with the help of centimeters scale; whichever was longer and the average was recorded in centimeters. the effective tillers from ten hills were counted and averaged to have hill−1 basis. the panicles which had at least one grain was considered as effective tillers. total tillers which had at least one leaf visible were counted. it includes both productive and unproductive tillers. number of tillers hill−1 were counted at harvest from ten randomly pre-selected hills and was expressed as number hill−1.to measure flag leaf width and length identify the flag leaf as the last leaf on the stem before flowering, then measure the width across the widest part of the leaf and the length from the base to the tip. measurement of yield attributes measurement of panicle length was taken from basal node of the rachis to apex of each panicle. each observation was an average of ten panicles. the total number of filled grains was collected randomly from selected ten plants of a plot and then average number of filled grains panicle−1 was recorded. the total number of unfilled grains was collected randomly from selected ten plants of a plot based on no or partially developed grain in spikelet and then average number of unfilled grains per panicle was recorded. for measuring 1000-grains weight (g) one thousand cleaned dried grains were counted randomly from each sample and weighed effect of plant spacing and leaf clipping on growth and yield of rice 72 by using a digital electric balance at the stage the grain retained 14% moisture and the mean weight were expressed in gram. measurement of yield and harvest index grain and straw obtained from each unit plot were sun-dried and weighed carefully. final grain yield was adjusted at 14% moisture. harvest index (hi) denotes the ratio of economic yield to biological yield and was calculated with the following formula: harvest index (hi%) = economic yield (grain weight) biological yield (total weight) ×100 statistical analysis using the statistical analysis tool costat v.6.400 (2008), data derived from various parameters were subjected to an analysis of variance (anova). in order to compare the treatments at a 5% level of significance (p ≤ 0.05), the mean and standard deviation (± sd) from three replications were determined. results and discussion plant height effect of spacing and leaf cutting observed in case of all the morphological parameters of brri dhan62 including plant height, flag leaf width and length and panicle length. for instance, among the three spacings plant height was marked top at s2 spacing whereas, in case of leaf cutting t0 showed best result. plant height was found to be statistically same in all the treatments irrespective of spacing and leaf cutting. but when in interaction highest plant height found in t0 × s2 and the lowest in t3 × s2 which shows 3 and 1% variation from the control, t0 × s1 (table 1). different plant spacing had significant influence on plant growth, yield and yield contributing characters might be due to availability of light, air and absorption of nutrient. bhowmik et al. (2012) observed that increase in spacing produced the highest plant height. similar results were also obtained from roy et al. (2017) that wider hill spacing produced the tallest plant than closer hill spacing. wider spaced plants received more moisture, light and nutrient which resulted in increase in plant height. flag leaf width and length among the spacings and leaf cutting plants flag leaf were longest at s1 and t0 treatments respectively. there was no statistical difference in case of flag leaf width and length irrespective of spacing and leaf cutting. yet the longest flag leaf was found in t0 × s3 and shortest in t3 × s2, indicating 30 × 25 cm2 spacing and no leaf cutting treatment combination had longest flag leaf. in case of width highest observed in t2 × s2 and lowest in t1 × s3. this indicates cutting of 2nd basal leaf with combination of 30 × 20 cm2 had wider flag leaf (table 1). panicle length spacing, leaf cutting and their combination treatments had varietal panicle length. among which highest panicle length was recorded in t0 × s2 indicating 30 × 20 cm2 spacing showed longest panicle, 3% longer than control t0 × s1 (30 × 15 cm2 spacing with no leaf cutting) (table 1). closer spacing produced higher number of grains panicle-1 than wider spacing. the number of infertile spikelet’s panicle-1 increased with wider spacing. a similar result observed from ahsan (2020) that no leaf clipping produced significantly longer (32.71 cm) panicle. 1000-grain weight weight of 1000-grain (g) under different spacing and leaf cutting, exhibited maximum yield at s1 and t0 treatments respectively. among the interaction highest 1000-grain weight 73 rahman et al. was 2% higher than the control at t1 × s2 combination indicating 30 × 20 cm2 spacing in combination of 1st basal leaf cutting recorded maximum yield. 1000-grain weight was lowest at t3 × s3 which indicates defoliation of 3rd basal leaf and 30 × 25 cm2 spacing reduced seed yield (table 1). similar results pronounced by hossain (2017) that the 1000-grain weight was significantly reduced in plants those had the leaves cut compared with the plant in control treatment and no leaf clipping produced highest 1000-grain weight which was 23.21 g. from the findings of laila et al. (2020) spacing had no significant effect on 1000-grain weight may due to genetic character. table 1. effect of spacing, leaf cutting and combination of treatment on plant height, flag leaf width and length, total and effective tiller and 1000-grain weight of brri dhan62 here, s1= 30 × 15 cm2 spacing, s2= 30 × 20 cm2 spacing, s3= 30 × 25 cm2 spacing, t0= no leaf cutting, t1= cutting of 1st basal leaf, t2= cutting of 2nd basal leaf and t3= cutting of 3rd basal leaf. the values in a column are presented as the mean ± sd. according to tukey’s hsd test, values labeled with different letters indicate that they are significantly different at p ≤ 0.05. number of tillers total and effective tiller number hill−1 showed significant difference at different spacing, leaf cutting and their combination treatments. effective and total tiller number were 40 and 28% greater at s3 spacing than their respective controls. maximum number of total tillers was observed at t3 × s3 whereas the lowest at t2 × s1. the highest number of total tillers was found to be 39% higher than the control t0 × s1. in contrary, the lowest total tiller number marked in t2 × s1 which is statistically similar to the control (table 2). treatment plant height (cm) flag leaf width (cm) flag leaf length (cm) panicle length (cm) 1000-grain weight (g) spacing s1 104.742 a 1.380 a 35.518 a 24.623 a 21.802 a s2 105.402 a 1.383 a 33.937 a 25.318 a 21.858 a s3 104.505 a 1.340 a 34.928 a 25.185 a 21.637 a leaf cutting t0 105.911 a 1.367 a 35.411 a 25.778 a 21.951 a t1 104.784 a 1.347 a 34.500 a 24.653 a 22.171 a t2 104.900 a 1.398 a 34.947 a 25.098 a 21.544 a t3 103.936 a 1.360 a 34.320 a 24.640 a 21.396 a spacing × leaf cutting t0 × s1 104.227 a 1.353 a 36.033 a 25.373 a 21.913 a t0 × s2 107.313 a 1.360 a 33.620 a 26.027 a 21.807 a t0 × s3 106.193 a 1.387 a 36.580 a 25.933 a 22.133 a t1 × s1 105.093 a 1.427 a 34.847 a 23.940 a 22.133 a t1 × s2 107.167 a 1.367 a 35.473 a 25.307 a 22.353 a t1 × s3 102.093 a 1.247 a 33.180 a 24.713 a 22.027 a t2 × s1 105.720 a 1.393 a 36.127 a 24.553 a 21.580 a t2 × s2 104.053 a 1.447 a 34.853 a 25.180 a 21.693 a t2 × s3 104.927 a 1.353 a 33.860 a 25.560 a 21.360 a t3 × s1 103.927 a 1.347 a 35.067 a 24.627 a 21.580 a t3 × s2 103.073 a 1.360 a 31.800 a 24.760 a 21.580 a t3 × s3 104.807 a 1.373 a 36.093 a 24.533 a 21.027 a effect of plant spacing and leaf clipping on growth and yield of rice 74 effective tiller number on the other hand recorded maximum at t1 × s3 and minimum at t2 × s1 indicating 30 × 25 cm2 spacing without leaf defoliation alleviated yield growth of rice plants. due to this spacing t1 × s3 combination showed 50% greater effective tiller number compared to control plants. again, in t2 × s1 treatment effective tiller number was reduced by 10% due to the cutting of 2nd basal leaf (table 2). table 2. effect of spacing, leaf cutting and combination of treatment on effective and total tiller hill−1, filled and unfilled grains panicle−1, and harvest index of brri dhan62 here, s1= 30 × 15 cm2 spacing, s2= 30 × 20 cm2 spacing, s3= 30 × 25 cm2 spacing, t0= no leaf cutting, t1= cutting of 1st basal leaf, t2= cutting of 2nd basal leaf and t3= cutting of 3rd basal leaf. the values in a column are presented as the mean ± sd. according to tukey’s hsd test, values labeled with different letters indicate that they are significantly different at p ≤ 0.05. productive tillers unit area−1 determined the final yield of rice. the same result was reported by hossain (2017). similar findings were reported by rasool et al. (2013) and mobasser et al. (2007). number of grains highest filled grain panicle−1 spotted at t1 × s2 and fewer at t3 × s3 treatment indicating that with higher leaf cutting and spacing filled grain number reduced. unfilled grains panicle−1 was at t0 × s1 that was same to t1 × s1 and t3 × s3 treatments. this number of unfilled grains was 75% higher than the lowest unfiled grain found in t0 × s2 (table 2). over exploitation of resources such as water, sunlight and, nutrients etc. may have favored 30 × 20 treatment effective tiller hill−1 (no) total tiller hill−1 (no) filled grains panicle−1 (no) unfilled grain panicle−1 (no) harvest index (%) spacing s1 10.967 c 12.708 b 84.767 a 22.350 a 43.329 b s2 12.518 b 13.533 b 85.733 a 19.033 b 46.313 a s3 15.388 a 16.268 a 84.883 a 19.100 b 43.620 b leaf cutting t0 12.880 a 13.947 a 86.378 a 18.222 b 43.982 ab t1 13.611 a 14.268 a 87.356 a 20.933 a 44.534 ab t2 12.180 a 13.783 a 86.000 a 19.733 ab 46.378 a t3 13.160 a 14.682 a 80.778 a 21.756 a 42.789 b spacing × leaf cutting t0 × s1 10.547 ef 12.040 c 84.800 a 23.667 a 42.760 b t0 × s2 13.067 a-e 13.930 a-c 87.400 a 13.467 d 45.065 ab t0 × s3 15.027 a-d 15.870 ab 86.933 a 17.533 b-d 44.121 ab t1 × s1 11.760 d-f 13.253 a-c 86.667 a 23.600 a 44.554 ab t1 × s2 13.253 a-e 13.695 a-c 88.267 a 22.533 ab 46.006 ab t1 × s3 15.820 a 15.855 ab 87.133 a 16.667 cd 43.043 b t2 × s1 9.520 f 11.982 c 87.467 a 20.600 a-c 44.807 ab t2 × s2 11.527 ef 12.775 bc 83.933 a 19.667 a-c 49.914 a t2 × s3 15.493 ab 16.592 a 86.600 a 18.933 a-c 44.413 ab t3 × s1 12.040 c-f 13.557 a-c 80.133 a 21.533 a-c 41.197 b t3 × s2 12.227 b-f 13.732 a-c 83.333 a 20.467 a-c 44.265 ab t3 × s3 15.213 a-c 16.757 a 78.867 a 23.267 a 42.904 b 75 rahman et al. cm spacing in obtaining the maximum grain yield. the finding agreed with shinde et al. (2011). the result is found more or less similar with the findings of ahsan (2020) where he observed that the maximum grain yield (5.44 t ha−1) was recorded at no leaf clipping (l0) treatment. hossain (2017) also found that the highest number of grains panicle−1 was obtained in no leaf cutting (control) treatment. moreover, the maximum number of unfilled grains panicle−1 (16.55) was recorded from no seedling clipping (s0) treatment from ahsan (2020) findings. harvest index harvest index (%) demonstrated difference at diverse spacing, leaf cutting, and their combination. at s2 × t2 treatment hi was found to be 7 and 5% higher than their respective controls. maximum hi was discovered at t2 × s2 marking 15% higher yield than control and minimum index at t3 × s1 indicating similar result. this scenario shows hi of rice can be accelerated by cutting of 2nd basal leaf in combination with 30 × 20 cm2 spacing (table 2). as optimum spacing (s2) showed highest filled grain panicle−1 thus results in maximum hi with no or optimum leaf clipping which is supported by ahsan (2020). although unfilled grain panicle−1 was highest in lower spacing (s1) thus results in lowest hi. mahato et al. (2007) also found that grain yield of rice under closer spacing’s was significantly higher than wider spacing’s which resulted in higher hi. grain yield grain yield hill−1 exhibited difference at spacing, leaf cutting, and their interaction treatments. maximum grain yield was recorded at t2 × s2 marked by 25% rise in comparison with control t0 × s1. but least grain yield was recorded at t3 × s1 (fig. 1). fig 1. fig 1. effect of spacing, leaf cutting and combination of treatment on grain yield (t ha−1) of brri dhan62. here, s1= 30 × 15 cm2 spacing, s2= 30 × 20 cm2 spacing, s3= 30 × 25 cm2 spacing, t0= no leaf cutting, t1= cutting of 1st basal leaf, t2= cutting of 2nd basal leaf and t3= cutting of 3rd basal leaf. the values in a column are presented as the mean ± sd. according to tukey’s hsd test, bars labeled with different letters indicate values that are significantly different at p ≤ 0.05. effect of plant spacing and leaf clipping on growth and yield of rice 76 straw yield in case of straw yield, highest straw yield was found at t3 × s1 and the least at t2 × s2 (fig. 2) which means no or minimal leaf clipping showed maximum straw yield while optimal leaf clipping does not result in significant changes which is supported by ahsan (2020). this may be due to the increase in plant height and number of tillers and panicle length. these results are found similar with those reported by abd el-hamed (2002) and el-rewainy (2002). fig 2. effect of spacing, leaf cutting and combination of treatment on straw yield (t ha−1) of brri dhan62. here, s1= 30 × 15 cm2 spacing, s2= 30 × 20 cm2 spacing, s3= 30 × 25 cm2 spacing, t0= no leaf cutting, t1= cutting of 1st basal leaf, t2= cutting of 2nd basal leaf and t3= cutting of 3rd basal leaf. the values in a column are presented as the mean ± sd. according to tukey’s hsd test, bars labeled with different letters indicate values that are significantly different at p ≤ 0.05. conclusion proper spacing and leaf cutting can alleviate growth and grain yield of rice. lower spacing can allow competition among plants for nutrition and growing space whereas wider spacing can make room for weeds and heterozygous plant species. similarly, removal of leaves at certain growth stage is crucial for plants. too much pruned or too bushy plants can reduce yield and yield related attributes. from the above findings, it could be concluded that most of the growth, yield, and yield-contributing characteristics of rice gave the best performance with 30 × 20 cm2 spacing in combination with the cutting of 2nd basal leaf. for this reason, further research needs to be executed for better understanding. references abd el-hamed, m.i. 2002. agricultural studies on rice. ms thesis. kafr elsheikh, tanta university, egypt. ahsan, m.n. 2020. influence of leaf clipping on the growth and yield of aus rice. ms thesis. sher-ebangla agricultural university, dhaka, bangladesh. 77 rahman et al. bhowmik, s.k., m.a.r. sarkar and f. zaman. 2012. effect of spacing and number of seedlings per hill on the performance of aus rice cv. nerica 1 under dry direct seeded rice (ddsr) system of cultivation. j. bangladesh agricultural university. 10(2): 191-196. el-rewainy, i.m.o. 2002. the effect of different nitrogen fertilizer sources on yield and some agricultural characters in rice. ph.d. thesis. shebin el-kom, menofiya university, egypt. hossain, m.j. (2017). effect of leaf cutting on growth and yield of modern aman rice varieties. ms thesis. sher-e-bangla agricultural university, dhaka, bangladesh. islam, m.s., n.r. sarker, m.y. ali, m.r. habib, m.m. billah, m.a.h. miah and m. shahjahan. 2017. comparative study on fodder and rice production with the emphasis of economic profitability. int. j. nat. social sci. 4: 01-05. laila, n., m.a.r. sarkar, s.k. paul and a. rahman. 2020. yield performance of aromatic fine rice as influenced by integrated use of vermicompost and inorganic fertilizers. j. bangladesh agricultural university. 18(2): 260–265. mahato, p., s.k. gunri, k. chanda and m. ghosh. 2007. effect of varying levels of fertilizer and spacing on medium duration rice (oryza sativa l.) in terai zone of west bengal. karnataka j. agril. sci. 20(2): 363-365. mazur, v.a., h.v. pantsyreva, k.v. mazur and i.m. didur. 2019. influence of the assimilation apparatus and productivity of white lupine plants. agron. res. 17(1): 206-219. mobasser, h., d. tari, d. vojdani, r. abadi and a. eftekhari. 2007. effect of seeding age and planting space on yield and yield components of rice (neda variety). asian j. of plant sci. 6(20): 438-440. rasool, f., r. habiba and m.i. bhat. 2013. agronomic evaluation of rice (oryza sativa l.) for plant spacings and seedlings per hill under temperate conditions. afr. j. agric. res. 8(37): 46504653. roy, s., n. islam, s. hoshain, a.k. hasan and k. hossen. 2017. effect of bed width and hill spacing on the performance of t. aman rice cv. super aman dhan. int. j. sustain. crop prod. 12(3): 1-6. shinde, s.d, b.s. raskar and b.d. tamboli. 2011. effect of spacing and sulphur levels on productivity of sesame (sesamum indicum l.) under summer condition. j. maharastra agric. univ. 36(1): 28-31. smith, m.r., i.m. rao and a. merchant. 2018. source-sink relationships in crop plants and their influence on yield development and nutritional quality. front. plant sci. 9: 1889. microsoft word 2. baj-467e bangladesh agron. j. 2024, 26(2): 7-15 effect of row orientation on productivity of sugarcane with potato as intercrop m.s. hossain1*, m. m. rashid1, m.a.t. sohel2, a.k.m.r. islam3 and m.s. islam4 1bangladesh sugarcrop research institute, regional station, thakurgaon, bangladesh 2on-farm research division, bangladesh sugarcrop research institute, ishurdi-6620, pabna, bangladesh 3agronomy & farming system division, bangladesh sugarcrop research institute, ishurdi-6620, pabna, bangladesh 4physiology and sugar chemistry division, bangladesh sugarcrop research institute, ishurdi-6620, pabna, bangladesh *corresponding author, email: atsohel@yahoo.com (received: 18 september 2023, accepted: 1 january 2024) keywords: sugarcane, row direction, internodes, germination, benefit cost ratio abstract an experiment was carried out at the regional sugarcrop research station (rsrs) farm, thakurgaon under the agro-ecological zone of old himalayan piedmont plain (aez-1) of bangladesh, during 2016-2017 to 2017-2018 cropping seasons to evaluate the impact of row orientation on the productivity of sugarcane with potato as intercrop. under the study eight treatments viz t1: single row cane (src) only in north-south direction, t2: src + potato in north-south direction, t3: src only in east-west direction, t4: src + potato in east-west direction,t5: paired row cane (prc) only in north-south direction, t6: prc + potato in north-south direction, t7: prc only in east-west direction and t8: prc + potato in east-west direction were tested following randomized complete block design with three replications significant differences were found among the observed parameters except germination (%) of setts, number of internodes per stalk and unit stalk weight of sugarcane. the highest number of tiller and millable cane population, cane yield and brix reading were achieved from the treatment src + potato in the north-south direction. the highest intercrop yield, equivalent cane yield of intercrop, total adjusted yield and gross return were obtained from the treatment prc + potato in north-south direction, but the highest net return and benefit cost ratio were obtained from the treatment src + potato in the north-south direction. having the highest cane yield, net return and benefit cost ratio with less variable cost, sugarcane planting in a single row system with potato as intercrop in a north-south row direction could be considered the best package practice for successful sugarcane farming. introduction sugarcane (saccharum officinarum l.) is a profitable cash crop grown mainly for sugar production. it is cultivated in more than 103 countries of the world with brazil as a major producer followed by brazil (829.74 million tons), india (446.89 million tons), thailand (144.41 million tons), china (121.21 million tons), pakistan (77.72 million tons) and mexico (65.40 million tons) (faostat, 2019). in bangladesh sugarcane was grown under many diverse agro-ecological conditions with an average production of about 3203 thousand tons (bb, 2019). it is the main source of sugar (80%) globally and holds a prominent position as a cash crop. the sugarcane juice is used for making white sugar, brown sugar, and jaggery (gur). the main byproducts of the sugarcane industry are bagasse and molasses. bagasse is mainly used as fuel. it is also used for the production of compressed fibre board paper, plastic and others. molasses is used in distilleries for the manufacturing of ethyl alcohol, butyl alcohol, citric acid etc. rum is the best potable spirit made from molasses. molasses is also used as an additive to feed for livestock. press mud can be used as soil amendment in saline and alkali soils. green tops of cane are a good source of fodder for cattle (shukla et al., 2017). it is a long duration crop that takes about 12-14 months from planting to harvesting which decreases economic return of the farmers compared to other crops. to get the higher economic returns from sugarcane field, appropriate inter-cropping practices with short duration crops might be the alternative way to increase total yield, interim and higher monetary return (islam et al., 2016). intercropping is the practice of cultivating two or more crops simultaneously on the same piece of land per year (guleria and kumar, 2016). the growth rate of sugarcane during its 8 hossain et al. initial stages (first 90-120 days) is rather slow, with the leaf canopy providing sufficient uncovered area for growing of other crops (shahana et al., 2019). in the early stage of growth, some short duration winter crops viz., vegetables, pulses, oil seeds and spices can be grown as intercrop in the vacant spaces between two rows of sugarcane (alam et al., 2008). similarly, the interaction between plant population and row orientation influences solar radiation interception by the plant canopy and soil moisture and nutrient uptake by the crops (tsubo et al., 2003). orientation of the rows also affects photosynthetic efficiency and canopy temperature as it affects interception of solar radiation by the crop canopy (drews et al., 2009). reducing space between rows or orientating rows to right angles (north-south) to sunlight direction increases weeds shading, water use efficiency and crop yields (fedelibus, 2005). north-south row had the potential for yield advantage and may be slightly preferable over east-west (dhillon et al., 1982). more radiation penetration and interception in north-south rows increased the crop profile temperature and decreased humidity within the canopy and made the crop micro-environment unfavorable for pests and diseases. so, the crops grown in north-south direction were found the most efficient in terms of producing more leaf area index, biomass and yield (das, 2014). improper row direction and seeding density is the most critical factors that reduce sugarcane yield in the country (mahmood et al., 2007). north to south direction gives the most sun exposure and allows for ample air circulation. when crops are planted east to west, the rows tend to shade each other. but information in this respect for sugarcane which remains in the field round the year is either lacking or scanty, and limited research has so far been done. given the above circumstances, the study was undertaken to determine the appropriate row orientation for sugarcane production with intercrop under the agro-ecological zone of the old himalayan piedmont plain of bangladesh. materials and methods the experiment was conducted at regional sugarcane research station (rsrs) farm, thakurgaon in bangladesh during 2016-2017 to 2017-2018 cropping seasons under irrigated conditions. the site represents the old himalayan piedmont plain (aez-1) with medium high land of typical sandy loam soil having ph 5.5. sugarcane (cv. isd 37) was planted in a single and paired row planting system, where potato (cv. cardinal) was planted as intercrop in between two rows/paired rows of sugarcane in the same land. the experiment was laid out in a randomized complete block design (rcbd) with three replications. the unit plot size was 8m  6m and the treatments were as follows t1: single row cane (src) only in north-south direction t2: src + potato in north-south direction t3: src only in east-west direction t4: src + potato in east-west direction t5: paired row cane (prc) only in north-south direction t6: prc + potato in north-south direction t7: prc only in east-west direction t8: prc + potato in east-west direction. two budded sugarcane setts were planted following end to end placement in trenches in midnovember of 2016 and 2017 for the two cropping seasons. in single row planting system, row to row distance was 100 cm where in paired row planting system, distance between two rows was 60 cm and two paired rows was 140 cm. the intercrop potato was planted in the vacant spaces between two rows/paired rows on the next day of the sugarcane plantation. fertilizers were applied following the recommended rate (barc, 2012). urea, tsp, mop, gypsum and zn sulphate for sugarcane @ 358, 275, 240, 194 and 7 kg ha-1, respectively and 210, 120, 180, 75 and 6 kg ha-1, respectively for potato as intercrop, respectively. pest and disease management and necessary intercultural operations like weeding, mulching, gap filling, irrigation, earthing-up, tying etc. were done accordingly in proper time. intercrop potato was harvested in mid-february of the following years and data were recorded properly. germination (%) of setts was counted at 30 days after planting (dap) and tiller population on 150 dap. stalk height, stalk diameter, unit stalk weight, number of internodes per stalk, number of millable cane, cane yield and brix (%) of cane juice were recorded at harvest. sugarcane was harvested after effect of row orientation on productivity of sugarcane with potato as intercrop 9 twelve months from plantation at maturity stage for every season. calculation of tiller mortality (%), equivalent cane yield of intercrop, total adjusted cane yield and economic return were done accordingly on the basis of present market price. fisher’s analysis of variance (anova) was used for statistical analysis of collected data and comparison of differences among treatment means. least significant difference (lsd) test was done at 5% level of probability (steel et al., 1996). statistix 10 (tallahassee fl 32317) was used for the determination of statistical differences. tiller mortality (%) = number of tiller number of millable cane number of tiller  100 the benefit cost ratio (bcr) indicated whether the cultivation was profitable or not, which was calculated as follows (cimmyt, 1988): benefit cost ratio = gross return (tk.ha-1) cost of production (tk.ha-1) gross return = value of cane and intercrop cost of production = sum of costs for the resources. results and discussion response of row orientation of sugarcane and its effect on germination (%) of setts, stalk height, stalk diameter, number of internodes per stalk and unit stalk weight were represented in table 1. table 1. effect of row orientation on germination (%) of sett, stalk diameter, no. of internode stalk-1 and unit stalk weight of sugarcane (pooled data, 2016-2017 to 2017-2018) treatments germination (%) stalk diameter (cm) internodes stalk−1 unit stalk weight (kg) t1: src only in north-south direction 78.14 2.29 ab 26 0.88 t2: src + potato in north-south direction 79.42 2.33 a 27 0.89 t3: src only in east-west direction 76.84 2.13 bc 26 0.82 t4: src + potato in east-west direction 79.24 2.20 abc 25 0.84 t5: prc only in north-south direction 76.67 2.15 bc 27 0.85 t6: prc + potato in north-south direction 77.64 2.24 abc 25 0.86 t7: prc only in east-west direction 76.50 2.10 c 27 0.87 t8: prc + potato in east-west direction 77.57 2.17 abc 26 0.88 lsd(0.05) ns ns ns ns in a column, figures with similar letters do not differ significantly at 5% level germination percentage germination percentage is the most critical factor that determines the varietal potential to exploit the available resources and ultimately affects on cane stand. in the study, germination percentage is not affected significantly by row orientation of sugarcane but the highest germination percentage of 79.42 was observed in t2 (src + potato in north-south direction) and the lowest germination percentage of 76.50 was observed in t7 (prc only in east-west direction). stalk height environmental factors and genetic characteristics of plants play an important role in determining the plant height and other physical characteristics. among different treatment combinations stalk height as obtained was significantly affected by row orientation of sugarcane and intercropping (fig. 1.). the highest stalk height of 3.20 m was observed in t2: src + potato in north-south direction. the lowest stalk height of 2.84 m was recorded in t7: prc sole in east-west directions. ruk et al. (2014) and karanja1 et al. (2014) mentioned the same result in their report. ruk et al. (2014) reported that height of cane 241.33 cm in north-south row direction than east-west row orientation (232.50 cm). karanja et al. (2014) also reported that sorghum plant height of 0.95 m oriented in north-south compared to 0.87 m in east-west row orientation. 10 hossain et al. fig. 1. effect of row direction on stalk height of sugarcane. stalk diameter the significant difference was observed in stalk diameter due to plantation with varied row orientation. the highest stalk diameter (2.33 cm) was found from the treatment t2 (src + potato in north-south direction) followed by t1 which was statistically similar and the lowest of 2.10cm was found from the treatment t7 (prc only in east-west direction). from the result, it was observed that a higher stalk diameter was found from the canes planted in the north-south direction and intercropping had no adverse effect on stalk diameter. similar result was reported by ruk et al. (2014). they reported that sugarcane planted in rows of north-south direction produced the higher cane diameter of 3.18 cm than the east-west row direction (3.06 cm). number of internodes the number of internodes per stalk was not differ significantly among the treatment combinations ranges from 25 to 27. this result was agreement with ruk et al. (2014). they showed that number of internode range (18-18.73) among the north-south and east-west row direction. unit stalk weight no significant difference was observed in unit stalk weight and ranged from 0.82 to 0.89 kg per stalk. the highest unit stalk weight of 0.89 kg was found from t2: src + potato in north-south direction and the lowest weight of 0.82 kg was found from t3: src only in an east-west direction. similar result was also observed by ruk et al. (2014) who observed that canes weight (1.5 kg cane−1) in the north-south direction and the lowest cane weight (1.4 kg) in the east-west row direction. results from this study further indicated that all the treatments exerted significant influence on yield and other yield attributes viz, tiller population, millable cane, cane yield and brix (%) of cane as presented in table 2. table 2. effect of row direction on number of tiller and millable cane production, cane yield and brix (%) of sugarcane (pooled data, 2016-2017 to 2017-2018) treatments tiller (103 ha−1) millable cane (103 ha−1) cane yield (t ha−1) brix (%) t1: src only in north-south direction 162.28 ab 91.87 a 78.36 abc 21.00 t2: src + potato in north-south direction 174.24 a 96.50 a 86.23 a 21.10 t3: src only in east-west direction 148.69 abc 88.54 ab 77.93 abc 20.00 t4: src + potato in east-west direction 152.13 abc 89.72 ab 85.89 ab 20.10 t5: prc only in north-south direction 152.52 abc 90.93 ab 72.03 c 20.33 t6: prc + potato in north-south direction 153.05 abc 91.76 ab 79.91 abc 20.00 t7: prc only in east-west direction 132.68 c 79.04 b 71.60 c 19.86 t8: prc + potato in east-west direction 139.88 bc 81.35 b 76.29 bc 19.70 lsd(0.05) 27.79 9.85 12.01 ns in a column, figures with similar letters do not differ significantly at 5% level 3.13 3.2 2.92 3.03 2.95 3.1 2.84 2.94 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 t1 t2 t3 t4 t5 t6 t7 t8 st al k h ei gh t ( m ) treatments effect of row orientation on productivity of sugarcane with potato as intercrop 11 tiller population the tillering potentiality of sugarcane ultimately affects cane yield positively. a significant difference in the tiller population was found among the treatment combinations. the highest number of tiller 174.24103 ha−1 was recorded in the treatment t2: src + potato in north-south direction and the lowest tiller of 132.68103ha−1 was recorded in the t7: prc only in the east-west direction. similar observation was reported by ruk et al. (2014); singh and sharma, (2019). they show that north-south row direction resulted in higher tiller than of 144.35 than other direction. millable cane the number of millable cane directly influences cane yield. the highest number of millable cane of 96.50×103 ha−1 was found from the treatment t2: src + potato in north-south direction which was statistically similar to other treatments except t7 and t8. the lowest millable cane of 79.04×103 ha-1 was found from the t7: prc only in east-west direction treatment. similar report was reported by ruk et al. (2014) who reported that effect of north-south row direction resulted in a higher millable cane of 144.35 ×103 ha−1 than the east-west row orientation (142.00 ×103 ha−1). tiller mortality (%) the highest tiller mortality (46.51%) was recorded in the treatment t8: prc + potato in eastwest direction while the lowest mortality of 40.04% was obtained in the treatment t6: prc + potato north-south direction. it was observed that among the treatments, higher tiller mortality was calculated with treatments that produced higher numbers of tillers but finally more millable canes were obtained with those treatments (fig. 2). fig. 2. effect of row direction on tiller mortality of sugarcane. cane yield the highest cane yield of 86.23 t ha−1 was obtained from the treatment t2 (src + potato in north-south direction) which was statistically similar with 91.87 t ha−1 obtained in t1 (src only in northsouth direction) and partially similar to the treatments t3, t4, t5 and t6. the lowest cane yield of 71.60 t ha−1 was obtained from the treatment t7 (prc only in east-west direction). similar report was reported by ruk et al. (2014) and karanja1 et al. (2014). ruk et al. (2014) reported that the crop planted in rows of north-south direction produced the maximum cane yield of 91.96 t ha−1 and the lowest cane yield of 88.267 t ha−1 in east-west row direction. karanja et al. (2014) also reported that north-south row orientation however, produced higher sorghum grain yields of 2.50 tons ha−1 than east-west 2.30 tons ha−1. results from the study further indicated that all the treatments exerted significant influence by the intercropping on cane yield, equivalent cane yield of intercrop and total adjusted cane yield presented in table 3. 37.93 44.12 36.66 43.32 35.75 40.23 39.44 46.51 0 10 20 30 40 50 t1 t2 t3 t4 t5 t6 t7 t8 ti lle r m or ta lit y (% ) treatments 12 hossain et al. table 3. intercrop yield, equivalent cane yield of intercrop and total adjusted cane yield as affected by row direction of intercropping with sugarcane cropping system (pooled data, 2016-2017 to 2017-2018) treatments cane yield (t ha−1) intercrop (potato) yield (t ha−1) equivalent cane yield of intercrop (t ha−1) total adjusted. cane yield (t ha−1) t1: src only in north-south direction 78.36 78.36 t2: src + potato in north-south direction 86.23 14.77 59.08 145.31 t3: src only in east-west direction 77.93 77.93 t4: src + potato in east-west direction 85.89 13.86 55.44 141.33 t5: prc only in north-south direction 72.03 72.03 t6: prc + potato in north-south direction 79.91 16.80 67.20 147.11 t7: prc only in east-west direction 71.60 71.60 t8: prc + potato in east-west direction 76.29 14.34 57.36 133.65 price of crops: sugarcane: 2,500 tk t−1 and potato: 10,000 tk t−1 brix percentage brix readings of sugarcane juice were significantly affected by row orientation and intercropping. the highest brix % of 21.66 was obtained from t2 (src + potato in north-south direction) which was statistically similar but numerically different with the other treatments except t7 (prc only in east-west direction) when the lowest brix % of 19.16 was obtained. similar result was in agreement with ruk et al. (2014). they found that the crop planted in rows of north-south direction resulted in maximum brix content of 22.76% and the lowest brix (22.75%) resulted in crops planted in east-west row direction. intercrop yield the overall yield performance of the intercrop potato was found satisfactory (table 3.) the highest potato yield of 16.80 t ha−1 as intercrop was obtained from t6 (prc + potato in north-south direction) followed by t2 (src + potato in north-south direction). the lowest potato yield as intercrop of 13.86 t ha−1was obtained from t4 (src + potato in east-west direction). adjusted cane yield adjusted cane yield is an important parameter for determining the total yield potentials of intercropped plot over the sole sugarcane plot (alam et al., 2000). the highest total adjusted cane yield of 147.11 t ha−1 was achieved from the treatment t6 (prc + potato in north-south direction) followed by 145.31 t ha−1 from t2 (src + potato in north-south direction) and the lowest total adjusted cane yield of 71.60 tha−1 was recorded from the treatment t7 (src only in east-west direction) (table 3). economic analysis the cost and returns of the experimentation under different treatments are presented in table 4. table 4. production cost, grows return, net return and benefit cost ratio (bcr) of sugarcane with potato cultivation as affected by row direction and planting method (pooled data, 2016-2017 to 20172018 cropping seasons) treatments total production cost total adjusted. gross return (tk ha−1) net return (tk ha−1) benefit cost ratio effect of row orientation on productivity of sugarcane with potato as intercrop 13 (tk ha−1) cane yield (t ha−1) t1: src only in north-south direction 95,000 78.36 1,95,975 1,00,975 2.06 t2: src + potato in north-south direction 1,70,000 145.31 3,63,275 1,93,275 2.14 t3: src only in east-west direction 95,000 77.93 1,94,825 99,825 2.05 t4: src + potato in east-west direction 1,70,000 141.33 3,53,325 1,83,325 2.08 t5: prc only in north-south direction 1,05,000 72.03 1,80,075 75,075 1.72 t6: prc + potato in north-south direction 1,80,000 147.11 3,67,775 1,87,775 2.04 t7: prc only in east-west direction 1,05,000 71.60 1,79,000 74,000 1.70 t8: prc + potato in east-west direction 1,80,000 133.65 3,34,125 1,54,125 1.85 price of crops: sugarcane: 2,500 tk t−1 and potato: 10,000 tk t−1 the highest gross return, net return and bcr of 3,63,275 tk ha−1, 1,93,275 tk ha−1 and 2.14, respectively are calculated in the treatment t2: src + potato in north-south direction and the lowest of these are from the treatment t7: prc only in east-west direction. from the calculation, it was observed that higher returns were obtained from the plots when the cane was planted in north-south direction irrespective of single or paired row planting system. it was also observed that a higher amount of earnings were obtained from the intercropped plots than the sole sugarcane plots. similar results confirmed with singh and sharma (2019) who depicted that north-south row orientation of wheat crops gave maximum bcr (1.58) as compared to east-west (1.55). conclusion the overall results of the experiment revealed that cane and intercrop yield and different yield contributing parameters of sugarcane were significantly affected by row orientation both in single or paired row planting systems. the highest cane yield, gross return, net return and bcr of 86.23 t ha−1, 3,63,275 tk ha−1, 1,93,275 tk ha−1 and 2.14, respectively were achieved from the plot when the cane was planted in north-south direction following single row system with potato as intercrop. it was observed that higher returns were obtained from the plots, when cane was planted in north-south direction irrespective of planting systems. it was also observed that higher yields were harvested in single row planting system irrespective of row directions and intercropped plots earned more than the sole sugarcane plots. it can be noted that sugarcane cultivation in north-south row direction following a single row planting system with potato as an intercrop is the best and may be recommended for farmers’ practice. references alam, m.j., m.s. hossain, a.k.m.r. islam, m.k. rahman and m.l. kabir. 2008. performance of jute varieties for seed production as first and mungbean as second intercrop under transplanted cane in paired row. bangladesh j. sugarcane. 30: 116-121. alam, m.j., m.a. islam, m.m. rahaman and a.k.m.m. zaman. 2000. impact of paired row sugarcane with double intercrops. bangladesh j. sugarcane. 22: 1-9. bangladesh bank. 2019. bangladesh production: sugarcane data remains active status in cecic. global data bases bangladesh. barc (bangladesh agricultural research council). 2012. fertilizer recommendation guide. barc, farmgate, dhaka, bangladesh. pp. 191. cimmyt. 1988. from agronomic data to farmers recommendations: an economics training manual. completely revised edition. mexico. pp. 31-45. 14 hossain et al. das, d.k. 2014. micrometeorological studies of crop row direction on growth and biotic stress in oilseed brassica. ms thesis. agricultural research institute. new delhi, india. dhillon, g.s., s. surjut, m.s. dhillon and a.s. atwal. 1982. developing agri-silvicultural practices: studies on the shading effect of eucalyptus on the yield of adjoining crops. indian j ecol. 9(2): 228-236. drews, s., d. neuhoff and u, kopke. 2009. weed suppression ability of three winter wheat varieties at different row spacing under organic farming conditions. weed res. 49: 526-533. fedelibus, m. 2005. grapevine row orientation offers light environment, growth and development of black night shade (solanum nigram l.). weed sci. 53: 802-812. faostat. 2019. food and agriculture organization of the united nations: economic and social department.the statistical division faostat. https://www.fao.org/faostat/en/#rankings/countries_by_commodity. guleria, g. and n. kumar. 2016. sowing methods and varying seed rates of cowpea on production potential of sorghum, sudan grass hybrid and cowpea: a review. agril. rev. 37: 290-299. islam, m.s., m.j. alam, m.s. hossain, m.m. rashid and m.k. rahman. 2016. productivity and profitability of flowermungbean sequential intercropping with sugarcane. bangladesh j. sugarcane. 37: 83-92. karanja, s.m., a.m. kibe1, p.n. karogo and m. mwangi. 2014. effects of intercrop population density and row orientation on growth and yields of sorghumcowpea cropping systems in semi-arid rongai, kenya. j. of agri. sci. 6: 34-43. mahmood, a., m. ishfaq, j. iqbal and m. s. nazir. 2007. agronomic performance and juice quality of autumn planted sugarcane (saccharum officinarum l.) as affected by flat, ditch and pit planting under different spatial arrangements. int. j. agri. biol. 9: 167-169. ruk, a. s., m. n. kandhro, s. k. baloch, s. u. baloch and a. b. baloch. 2014. impact of sett placement methods and row directions on growth and yield of sugarcane variety lrk-2001. persian gulf crop pro. 3(2): 5369. shahana, f., y. bharati and b. joseph. 2019. identification of profitable intercrops in summer sugarcane in ntz. j. pharmacogn. phytochem. 8(5): 1602-1604. shukla, s.k., l. sharma, s.k. awasthi and a.d. pathak. 2017. sugarcane in india: package of practices for different agro-climatic zones. icar-indian institute of sugarcane research. pp. 1-64. singh, k. and r. sharma. 2019. effect of different methods of sowing and row orientation on growth, yield and quality of wheat (triticum aestivum l.). agric. sci. digest., 39(1): 51-54. steel, r.g.d., j.h. torrie and d.a. dicky. 1996. principles and procedures of statistics, a biometrical approach. 3rd edn. mcgraw hill, new york. tsubo, m., e. mukhala, h.o. ogindo and s. walker. (2003). productivity of maize-bean intercropping in a semiarid region of south africa. water sa. 29(4): 381-388. chapter iv bangladesh agron. j. 2023, 26(1): 96-103 effects of planting geometry and fertilizer management on light interception, chlorophyll content and productivity in baby corn cultivation s.s. kakon*, j.a. chowdhury, m.z. ali, m.r. karim and d.a. chowdhury agronomy division, bangladesh agricultural research institute, joydebpur, gazipur 1701, bangladesh *corresponding author, email: kakonbari@gmail.com (received: 28 august 2023, accepted: 20 september 2023) keywords: light interception, chlorophyll content and productivity, baby corn abstract a field experiment was conducted during during rabi seasons (december to march) of 2019-20 and 2020-21 to find out optimum plant spacing and fertilizer levels on yield of baby corn. three plant spacing viz, s1=40 cm × 20 cm (1,25000 plants ha−1), s2=50 cm × 20 cm (100000 plants ha−1) and s3 =60 cm × 20 cm (83333 plants ha−1) and three fertilizer doses viz, f1 = 150305025-3. 51.5 kg ha−1of npksznb (recommended fertilizer dose for baby corn), f2 = f1 + 25% npk and f3 = f1 + 50% npk, were used as treatments. results revealed that, planting geometry and fertilizer levels showed great influence on leaf area index (lai), light interception, dry matter production and yield of babycorn. lai was found the highest with the population of 125000 plants ha−1 receiving n225 p45 k75 kg ha−1.light absorption was maximum at densely plant population with n225p45k75 kg ha−1. response of soil-plant-analysis development (spad) value to planting geometry and fertilizer level was found significant. plants grown with 40 cm × 20 cm spacing (125000 plants ha−1) with recommended ferltilizer dose + 50% npk of rf gave the highest dehusked cob yield over the years (3.42 and 3.73 t ha–1) which was followed by 40cm × 20 cm (1,25,000 plants ha−1) with recommended fertilizer dose + 25% n-p-k of rf. though s1f3 combination gave the highest gross return (tk.333140 ha– 1 in 2019-20 and tk. 378900 ha–1 in 2020-21) but the highest benefit cost ratio over the years (3.64 and 3.83) was recorded in s1f2 treatment. the overall results indicated that 40 cm × 20 cm (1,25,000 plants ha−1) with fertilizer dose of rfd + 25% npk (n187.5 p37.5k62.5 s25zn3. 5b1.5 kg ha−1) might be economically profitable for baby corn production. introduction babycorn (zea mays l.) is an immatured, dehusked and unfertilized maize ear, harvested within two days of silk emergence but prior to fertilization (ramchandrappa et al., 2004). change in food habit from non-vegetarian to vegetarian aggravated the consumption of vegetables especially babycorn. babycorn ends its life cycle within 75 days and enters its reproductive phase during 50-55 das. nitrogen is the most important nutrient for maize production and application of varied levels had significant influence on growth and yield of babycorn (thakur et al.,1997). it is a low calorie vegetable having higher fibre content without cholesterol. besides nutritive advantage, it is also free from residual effect of pesticides as it is harvested within a week of tassel emergence and the young cob is wrapped up tightly with husk and well protected from insects and pests recently it is becoming popular very rapidly as vegetables, salad, pasta, soup, pakora, chutney, cutlets chat, dry vegetable. to sustain the heavy cattle population, baby corn can provide a valuable supplementary source of green fodder. optimum crop geometry is one of the important factors for higher production leading to efficient utilization of resources and also harvesting as much as solar radiation and in turn better photosynthesis. the yield of baby corn of our country is 0.99-1.1 t ha−1 (bari, 2008). but its potentiality is 5 t ha−1 (bari, 2004). nevertheless, it is effects of planting geometry and fertilizer management on baby corn 97 not cultivated all over the country due to the lack of appropriate production technology. growth of baby corn are affected by cultural management practices especially fertilizer application. the application of 150:75:40 kg ha−1 npk + 10 t fym was found to be optimal for obtaining high baby corn and fodder yields with good quality (ramchandrappa et al., 2004). though the spacing requirements of grain and fodder maize are well defined, such information is meager in baby corn. the duration of crop being short, the need for nutrient management and other package of practices may also differ from the grain or fodder crop of maize. therefore, the experiment was undertaken to find out optimum plant spacing and fertilizer levels on yield of babycorn. materials and methods the experiment was conducted at the research field of agronomy division bari, gazipur, bangladesh during rabi season (december to march) of 2019-2020 and 2020-2021. the soil was clay loam with ph 6.1. soils of the experimental plots were collected and analyzed. the average maximum (30.5°c) temperature was found in the month of december at early stage of crop establishment and minimum (7.5°c) in the month of february during the crop growing season (figure 1). the physical and chemical properties of soil are presented in table 1. table 1. physical and chemical properties of experimental soil at gazipur, bangladesh ph om (%) total n (%) exchangeable k (meq 100g soil−1) available p (g ml−1) available s (g ml−1) available zn (µg ml−1) available b (g ml−1) 6.23 1.29 0.112 0.098 15.23 24.94 0.654 0.168 vl vl vl o o l vl critical levels 0.12 7.0 10.00 0.60 0.20 l= low, vl= very low three plant spacing viz., s1= 40 cm × 20 cm (1,25000plants ha−1), s 2= 50 cm × 20 cm (100000 plants ha−1) and s3 = 60 cm × 20 cm (83333plants ha−1) and three fertilizer doses viz., f1 = 150305025-3. 51.5 kg ha−1 npksznb (recommended fertilizer dose), f2 = f1 + 25% npk and f3 = f1 + 50% npk, were used. the experiment was laid out in a randomized complete block design with three replications. the unit plot size was 4 m × 3.6 m. seeds of bari baby corn-1 were sown on 12 december 2019 and on 3 december 2020. fertilizers were applied as per treatments. one-third of nitrogen and full amount of triple super phosphate (tsp), muriate of potash (mop), zinc sulphate and boric acid were applied at the time of final land preparation. the remaining n (urea) was top dressed in two equal splits at 25 das and 45 das, respectively and mixed thoroughly with the soil as soon as possible for better utilization. a light irrigation was given after sowing of seeds for uniform germination. two irrigations were done at 30 and 45 das. thinning’s were done at 10 das and weeding at 15 and 25 das. leaf area was measured by an automatic leaf area meter (l13200 c, licor, usa). for dry matter estimation, 5 plants were sampled started from 20 dae at 15 days interval up to maturity. dry weight of the samples was taken after drying at 80c in an oven for 72 h. cgr (g m-2 day−1), was calculated using equation as suggested by yellam as follows. light interception (li) by the crop was recorded at five times, for example, 25, 45, 60 das and at harvest at around 11:30 am to 13:00 pm of baby corn by sunfleck ceptometer (model decagon, pulman, washington, usa). four readings each of parinc and part were recorded at different spots of each plot. the proportion of intercepted par (parint) was calculated using the following equation and expressed in percentage: light interception {parint (%)} = parinc – part parinc × 100 where, parinc = incident par, part = transmitted par, parint = intercepted par 98 kakon et al. soil-plant-analysis development (spad) value. leaf chlorophyll content may be used as an indirect indicator of crop n status. chlorophyll meter values (spad) were taken using a portable spad meter (model spad-502, minolta crop., ramsey, nj) starting from 35 das with 15-day interval. bari babycorn-1 was harvested on 04 march 2020 (85 days after sowing) and on 08 march 2021. the yield component data was taken from 5 randomly selected plants from each plot. at harvest, the yield data was recorded plot wise. the collected data were analyzed statistically and means were adjudged by lsd test at 5% level of significance using mstat-c package. fig. 1. mean temperature prevailed during baby corn growing periods. results and discussion growth analysis leaf area index (lai) varied at different plant spacing and fertilizer level. lai increased up to 60 das and thereafter decreased in all treatments (fig. 2). maximum lai (3.89 in 2019-20 and 3.98 in 2020-21) was recorded at 65 das in s1f3 (125000 plants ha−1× × n 225p45k75kg ha−1) treatment followed by s1f2 (100000 plants ha−1 ×× n187.5 p37.5k62.5kg ha−1) treatment. higher lai indicates better leaf area expansion, which might help in solar radiation interception for more dry matter production. the lowest leaf area index (1.5 in 2019-20 and 2.10 in 202021) was found in s3 × f1followed by s2 × f1 treatment. higher leaf area index in closer spacing was observed due to increased plant density which accommodates more number of plants and can also be ascribed to lesser value of spacing (wasnik et al., 2012). total dry matter (tdm) production increased gradually with the advancement of plant growth in both the plant spacing and different fertilizer doses (figure 3). tdm of baby corn was higherins1f3 (125000 plants ha−1 × n225p45k75kg ha−1) followed by s1f2 treatment. the lowest tdm was observed from s2 × f1 treatment. total dry matter reduced in plant spacing s3 (60cm × 20 cm) under all fertilizer treatments. it might be due to lower population (83,333plants ha−1) and leaf senescence caused by might reduce the photosynthetic efficiency and effects of planting geometry and fertilizer management on baby corn 99 ultimately reduced the dry matter accumulation (figure 2). the treatments which gave the higher value in leaf area index (lai) were performed better in total dry matter production. similar findings were also observed with tollenaar et al. (1997). a) 2019-2020 b) 2020-2021 fig. 2. leaf area index of baby corn plant as influenced by planting density and fertility level. a) 2019-2020 b) 2020-2021 fig. 3. total dry matter of baby corn plant as influenced by planting density and fertilizer levels. significant effect on cgr value at all growth periods was found in both the plant spacing and different fertilizer doses (figure 4). cgr values were increased with the progress of the growth and development of the crop. cgr of baby corn was higher in s1f3(125000 plants ha−1×× n225p45k75kg ha−1) followed by s1f2 treatment. the lowest cgr was observed from s2 × f1 treatment. cgr reduced in plant spacing s3 (60cm × 20 cm) under all fertilizer treatments. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 20 35 50 65 80 le af a re a in d e x days after sowing s1x f1 s2x f1 s3x f1 s1x f2 s2x f2 s3x f2 s1x f3 s2x f3 s3x f3 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 20 35 50 65 80 le af a re a in d e x days after sowing s1x f1 s2x f1 s3x f1 s1x f2 s2x f2 s3x f2 s1x f3 s2x f3 s3x f3 0 200 400 600 800 1000 1200 1400 1600 1800 20 35 50 65 80 to ta l d ry m at te r (g m – 2 ) days after sowing s1x f1 s2x f1 s3x f1 s1x f2 s2x f2 s3x f2 s1x f3 s2x f3 0 200 400 600 800 1000 1200 1400 1600 1800 20 35 50 65 80 to ta l d ry m at te r (g m – 2 ) days after sowing s1x f1 s2x f1 s3x f1 s1x f2 s2x f2 s3x f2 s1x f3 s2x f3 100 kakon et al. a) 2019-2020 b) 2020-2021 fig. 4. crop growth rate of baby corn plant as influenced by planting geometry and fertilizer levels. light interception light interception steadily increased up to 60 das and decreased at harvest. light interception varied at different plant spacing and fertilizer doses (figure 5). a) 2019-2020 b) 2020-2021 fig. 5. light interception by baby corn canopy as influenced by planting density and fertilizer levels. combination of s1f3 (125000 plants ha−1 × n 225p45k75 kg ha−1) was favorable for light penetration to the upper of the canopy, which resulted better li and the lowest li was found in s3f1 (83,000 plants × 150305025-3. 51.5 kg ha−1npksznb). higher light absorption by the plants of treatment s1f3 is presumably because of larger leaf surface availability for 0 5 10 15 20 25 30 35 40 0-20 20-35 35-50 50-65 c ro p g ro th r at e ( g m – 2 d ay – 1 ) days after sowing s1× f1 s2× f1 s3× f1 s1× f2 s2× f2 s3× f2 s1× f3 s2× f3 s3× f3 0 5 10 15 20 25 30 35 40 45 0-20 20-35 35-50 50-65 c ro p g ro w th r at e ( g m – 2 d ay – 1 ) days after sowing s1× f1 s2× f1 s3× f1 s1× f2 s2× f2 s3× f2 s1× f3 s2× f3 s3× f3 0 10 20 30 40 50 60 70 80 90 100 45 60 at harvest l ig h t in te rc e p ti o n (% ) days after sowing s1x f1 s2x f1 s3xf1 s1xf2 s2xf2 s3x f2 0 10 20 30 40 50 60 70 80 90 45 60 at harvest l ig h t in te rc e p ti o n (% ) days after sowing s1x f1 s2x f1 s3xf1 s1xf2 s2xf2 s3x f2 https://www.hindawi.com/journals/tswj/2013/193018/fig3/ effects of planting geometry and fertilizer management on baby corn 101 photosynthesis as evident by higher leaf dryweight. this indicates that population is the main factor influencing the net radiation absorbed by the plants. higher penetration of radiation below the canopy indicates lower interception of solar radiation at the canopy. the maximum light was intercepted at 60 das corresponded to higher lai. these results indicated that the more the lai, the greater the light interception. these results are in conformity with the findings of several earlier researchers amanullah et al., (2010). spad value spad value was influenced by planting geometry and fertilizer level (figure 5). spad meter measure the leaf greenness which indicated the leaf chlorophyll content. regardless of treatment, spad values decreased with the plant age (figure 6). maximum spad values were observed at 65 das which declined progressively reaching the lowest at 80 das. the higher spad values of baby corn leaves at 65 das were probably due to the less sink demand for n from the source (leaf). spad value increases with the increase of fertilizer (especially nitrogen). conversely, lower spad values at 80 das and afterwards might have been due to remobilization of n from leaves to reproductive organs as grain formation was started after 60 das. spad values increased with the increase of fertilizers levels irrespective of population density. the highest spad value was found in s1f3 (125000 plants ha−1×× n225p45k75 kg ha−1). fig. 6. spad value on baby corn plant as influenced planting geometry and fertility levels. yield component and yield plant population, yield components and yield of baby corn were significantly affected by plant spacing and fertilizer doses (table 2) in both the years. number of cob per plant, cob wt. with husk, dehusked cob weight, dehusked cob yield and fodder yield varied significantly due to variation of treatments. maximum plants were recorded in s1f1, s1f2 and s1f3 treatments and minimum plants were recorded in s3f1, s3f2s3f3 treatments. significantly the highest number of cob per plant (2.80 in 2019-20 and 3.00 in 202021), dehusked cob weight/ plant (69.04g in 2019-20 and 58.67g in 2020-21) were obtained from s3f3 treatment followed by, s2f3 treatment. higher dehusked cob yield (3.42t ha−1 in 201920 and 3.73 t ha−1 in 2020-21) was recorded from s1f3 treatment followed by s1f2 treatment.it might be due to higher number of plants. the result coincides with the findings of kunjir et al., (2007). the lowest green cob yield average over the years (2.32 and 2.36 t ha−1) were obtained from s3f1 treatment which was statistically similar with s2f1 treatment. 0 10 20 30 40 50 60 70 35 50 65 80 s p a d v a lu e days after sowing s1x f1 s2x f1 s3xf1 s1xf2 s2xf2 s3x f2 s1x f3 s2xf3 s3xf3 102 kakon et al. table 2. plant population, yield attribute and yield of baby corn as influenced by plant spacing and fertilizer levels (2019-20 and 2020-21) treatment plant m−2 (no.) cob wt. with husk (g plant−1) cob wt. dehusked (g plant−1) cob plant−1 (no.) 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 s1× f1 10.00 10.34 97.64 116.33 30.94 31.30 2.53 2.51 s2× f1 8.00 8.10 109.80 119.59 34.13 34.03 2.59 2.67 s3× f1 6.33 6.74 118.50 131.33 38.38 42.07 2.68 2.73 s1× f2 9.67 9.87 103.40 121.33 48.51 41.78 2.57 2.67 s2× f2 7.67 7.74 113.25 127.00 53.58 48.67 2.64 2.70 s3× f2 6.67 6.77 121.93 144.00 59.02 54.00 2.72 2.78 s1× f3 9.67 9.59 109.80 126.90 56.57 49.63 2.61 2.60 s2× f3 7.00 7.63 118.65 131.33 62.17 54.00 2.70 2.70 s3× f3 6.67 6.62 127.20 147.33 69.04 58.67 2.80 3.00 lsd(0.05) 2.65 0.20 11.23 1.17 3.31 1.12 0.21 0.055 cv (%) 4.30 3.44 3.63 3.56 4.65 4.41 5.05 4.03 treatment yield dehusked (t ha−1) yield withhusk (t ha−1) fodder yield (t ha−1) 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 s1× f1 2.65 2.83 11.45 12.08 28.26 29.63 s2× f1 2.49 2.62 9.42 10.84 26.01 25.93 s3× f1 2.32 2.36 8.86 9.80 24.02 24.07 s1× f2 3.30 3.57 13.50 13.33 31.18 32.10 s2× f2 2.71 3.12 11.89 12.00 29.64 29.32 s3× f2 2.50 2.71 10.06 11.02 26.94 26.85 s1× f3 3.42 3.73 14.02 14.15 32.98 33.33 s2× f3 3.01 3.24 12.50 12.90 31.01 32.10 s3× f3 2.70 2.81 11.03 11.57 28.05 27.47 lsd(0.05) 0.13 0.08 3.05 0.14 4.20 0.92 cv (%) 4.73 3.29 6.01 5.68 5.61 5.83 significantly the highest green fodder yield was recorded in s1f3 (32.98 t ha−1in 201920 and 33.33 t ha−1 in 2020-21) treatment. hussain (2014) reported that higher dose of fertilizer application resulted the increased fodder yield. the lowest fodder yield was obtained from s3f1 treatment in both the years. yield attributes increased with increased rates of n might be due to the fact that application of nitrogen to the maize plants maintained greenness of leaves for longer period which in turn helped in greater dry matter accumulation and this might have contributed much as a major source for the development of sink and thereby improved the yield attributes. significantly the highest fodder yield was recorded in closer spacing with higher level of npk indicating a faster growth under influence of higher level of npk fertilization might have played a significant role in reducing competition for photosynthates and nutrients with other plants resulting in healthy plants. cost benefit analysis cost and return analysis is an important tool to evaluate the economic feasibility of crop production. benefit cost analysis of baby corn production has been presented in table 3. gross return and bcr depends on grain yield. among the treatments, the highest gross return (tk. 333140 ha–1in 2019-20 and tk.378900 ha–1 in 2020-21) was obtained from s1f3 treatment effects of planting geometry and fertilizer management on baby corn 103 and the lowest gross return (tk. 226477 ha−1 in 2019-20 and tk.267350 ha−1in 2020-21) was found in s3f1 treatment. the highest gross margin (tk. 239685 ha−1 in 2019-20 and tk.278949 ha−1 in 2020-21) was obtained from s1f3 treatment. the highest benefit cost ratio (3.64 in 201920 and 3.80 in 2020-21) was also obtained from s1f2 treatment (table 3) which was followed by s1f3 and s2f3. table 3. cost benefit analysis of babycorn as influenced by planting geometry and fertilizer level spacing fertilizer gross return (tk. ha−1) cost of production (tk. ha−1) gross margin (tk. ha−1) bcr 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 s1× f1 278683 329350 84560 92752 194123 236598 3.30 3.55 s2× f1 243073 292250 81820 88552 161253 203698 2.97 3.30 s3× f1 226477 267350 77450 85352 149027 181998 2.92 3.13 s1××f2 317917 360450 87280 94231 230637 266220 3.64 3.83 s2××f2 290897 326600 83020 90649 207877 235952 3.50 3.60 s3×× f2 255380 299550 79350 87449 176030 212102 3.22 3.43 s1× f3 333140 378900 93455 99951 239685 278949 3.56 3.79 s2××f3 305033 354000 87850 94745 217183 259255 3.47 3.74 s3××f3 272610 310900 81665 89545 190945 221355 3.34 3.47 price (tk.kg−1): baby corn (with husk) = 12 in 2019-20 and 15 in 2019-20; fodder = 5 conclusion results reveled that fertilizer dose 187.537.562.5253.51.5 kg ha-1 of npksznb (rfd + 25% npk) with plant spacing 40 cm × 20 cm would be optimum for getting higher yield and better economic return at joydebpur. references amanullah, a., m. asif and k. nawab. 2010. impact of planting density and p-fertilizer source on the growth analysis of maize. pak. j. bot. 42(4): 2349–2357. bari. 2008. bari annual research report. 200708. effect of season and population density on growth, fodder production and yield of baby corn at different locations. agronomy division, bari, rars, hathazari, chittagong, bangladesh. bari. production technology of baby corn (in bengali). agronomy division, bari, joydebpur, gazipur, bangladesh. hussain, a. 2014. effect of different combinations of organic and inorganic nutrients on productivity and profitability of baby corn varieties in kashmir valley. ph.d. thesis, sher-e-kashmir university of agricultural sciences & technology of kashmir, division of agronomy, shalimar campus, srinagar– 190025. kunjir, s.s., s.a. chavan, s.b. bhagat and n.b. zende. 2007. effect of planting geometry, nitrogen levels and micronutrients on the growth and yield of sweet corn. crop prot. prod. 2: 2527. ramachandrappa, b.k., i.i.v. nanjappa and i.i.k. shivakumar. 2004. yield and quality of baby corn (zea mays l.) as influenced by spacing and fertilization levels. acta agron. hung. 52: 237-243. thakur, d.r., o.m. prakash, p.c. kharwara and s.k. bhalla. 1997. effect of nitrogen and plant spacing on growth, yield and economics of baby corn (zea mays). indian. j. agron. 42(3): 479-483. tollenaar, m., a. aguilera and s.p. nissanka. 1997. grain yield is reduced more by weed interference in an old than in a new maize hybrid. agron. j. 89: 239-246. wasnik, v.k., a.p.k. reddy and s.s. kasbe. 2012. performance of winter maize under different rates of nitrogen and plant population in southern telangana region. crop res. 44(3): 269-273. microsoft word 5. baj-471e bangladesh agron. j. 2024, 26(2): 34-40 growth and yield of lentil as influenced by zinc and boron management a. kumar, p.k. biswas* and a. rahman department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: parimalbiswas@hotmail.com (received: 07 december 2023, accepted: 29 april 2024) keywords: zinc, boron, organic manure, foliar spray, bari masur-8, binamasur-8 abstract a field experiment was conducted at sher-e-bangla agricultural university, dhaka-1207, bangladesh, during the period from november 2021 to march 2022 to evaluate the influence of micronutrients management on growth and yield of two lentil varieties viz., bari masur-8 (v1) and binamasur-8 (v2) and 6 micronutrients management (no fertilizer f1, recommended fertilizer dose (rfd) (40-90-40-55 kg ha−1 of urea-tsp-mop-gypsum) with 10 kg ha−1 znso4 as basal f2, rfd with zinc (zn) as foliar spray f3, rfd with zn and boron (b) as foliar spray f4, 50% rfd + 50% cow dung (5 t ha−1) f5 and 50% rfd + 50% cow dung + zn and b as foliar spray f6). no significant effect had found for variety except 1000-seed weight but micronutrients management along with interactions significantly effects on all studied parameters of lentil. the higher 1000-seed weight (34.16 g) was recorded in bari masur-8. the highest plant height (37.09 cm), number of branches plant−1 (7), dry weight of root plant−1 (159.17 mg), dry weight of shoot plant−1 (3319.33 mg) and number of pods plant−1 (62) was observed at f6 treatment. the highest 1000-seed weight (31.68 g) were recorded at f2 treatment. the highest weight of nodules plant−1 (10.33 mg at 60 das), seed yield (2.62 t ha−1), straw yield (2.12 t ha−1) and biological yield (4.74 t ha−1) were found at f3 treatment. the highest plant height (38.45 cm), number of branches plant−1 (7), number of pods plant−1 (63), seed yield (2.91 t ha−1) and harvest index (58.65%) were recorded at v2f6 whereas the highest weight of nodules plant-1 (26 mg), straw yield (2.22 t ha−1) and biological yield (5.02 t ha−1) were found at v1f3 but the highest 1000-seed weight (34.87 g) at v1f1. the highest number of seeds pod−1 (1.83) was found at v2f1. so, two varieties showed similar performance on yield. foliar application of zn has the potentiality to increase seed yield. the variety binamasur-8 with 50% rfd + 50% cow dung + zn and b (f6) as foliar spray could bring maximum yield (2.91 t ha−1) of lentil followed by treatment f2, f3, and f4. introduction pulses are vital components in diversification of bangladesh’s predominantly rice-based cropping system. lentil (lens culinaris medik) is an important source of nutritional security, protein content of 18-30% and essential micronutrients, e.g., fe, zn and β-carotene for improving health of humans and domestic animals (togay et al., 2015; bhatty, 1988). lentil area and production in bangladesh was about 1.41 lakh ha and 1.77 metric tons with an average yield of 1.26 t ha−1 which contributed about 35% to the total pulses production in bangladesh (bbs, 2021). variation of seed yield and other yield attributes of lentil for different varieties were reported by khatun et al. (2021) and zaman et al. (2022). singh and bhatt (2013) reported that micronutrients required in small amount but contributed significantly on seed yield of lentil (16.2%) by increasing the growth and uptake of nutrients. combined use of different micro and macronutrients can augment seed yield by 55 to 60%, of which 20 to 25% could be ascribed to the micronutrients (islam et al., 2018). hossain et al. (2020) reported the highest nutrient uptake, maximum nodulation (at 68 das, 63.5 plant−1) and the highest protein content (26.6%) in seed from the micronutrients (zn, b and mo) application in lentil. foliar application of micronutrients was 6 to 20 times more useful than the soil application and improves the nutrition (arif et al., 2006). foliar application of zn reduces the micronutrient deficiencies and it was an efficient method because nutrients are easily absorbed through leaves and is best option to 35 kumar et al. compensate micronutrient deficiencies in shorter period of time under rainfed regions (nasiri et al., 2010). combined application of zn and b significantly increased the plant height, root length, leaf area index, shoot and root dry weight and chlorophyll content (panhwar et al., 2011). therefore, the study was undertaken to compare the yield and other attributes of two lentil varieties and determine the effect of zn and b on lentil yield and also find out the interaction of variety and micronutrient (zn and b) management on growth and yield of lentil. materials and methods the experiment was conducted during november 2021 to april 2022 at the agronomy field of sher-e-bangla agricultural university, dhaka-1207, bangladesh. the seeds of lentil var. bari masur8 and binamasur-8 were used as plant materials and the seeds were collected from bangladesh agricultural research institute (bari), joydebpur, gazipur and bangladesh institute of nuclear agriculture (bina), mymensingh, respectively. the experiment was laid out in a split-plot design with three replications. the treatments were two variety viz., i) bari masur-8 (v1) and ii) binamasur-8 (v2) in the main-plot and six different fertilizer management viz., i) no fertilizer (f1); ii) recommended n, p, k, and s (rfd) with zn as basal (f2); iii) rfd with zn as foliar spray (f3); iv) rfd with zn and b as foliar spray (f4); v) 50% rfd + 50% cow dung (f5), and vi) 50% rfd + 50% cow dung + zn and b as foliar spray (f6) in the sub-plot. the basal recommended dose i.e., urea (45 kg ha−1), tsp (90 kg ha−1), mop (40 kg ha−1), gypsum (55 kg ha−1), znso4 (10 kg ha−1) and boric acid (10 kg ha−1) along with cow dung (5 t ha−1) were used in the experiment as per treatment during final land preparation. the foliar application of zn and b were applied as per treatment during flower initiation. the seeds of bari masur-8 and binamasur-8 were sown by hand in 30 cm apart lines with continuous spacing at about 3 cm depth on 24 november, 2021. irrigation was given to each plot, first irrigation as pre-sowing and other two irrigations 3 days before weeding. two hand weeding were done for all the treatments on 15 and 30 das. the field was infested by different insects and diseases those controlled by applying appropriate ways in time. five plants plot−1 was randomly selected for collecting plant height, number of branch plant−1, dry weight of root and shoot at stipulated dates. the inner six lines were harvested for recording yield and yield attributes data. the seed yield and straw yield were recorded at 12% moisture level. statistical analyses were done by using the cropstat computer package and the mean differences among the treatments were compared by least significant difference (lsd) test at 5% level of significance following gomez and gomez (1984). results and discussion effect of variety all the studied characters showed non-significant variation between the two varieties except 1000-seed weight where bari masur-8 (34.16 g) showed higher 1000-seed weight compared to that of binamasur-8 (28.28 g) (table 1-3). similar variation of 1000-seed weight of lentil varieties was also found by zaman et al. (2022) and khatun et al. (2021). effect of micronutrient management the fertilizer treatments showed significant variations on most of the studied parameters where the highest plant height (37.09 cm), branches plant−1 (7), shoot dry weight plant−1 (3319.33 mg), pods plant−1 (62) were recorded from the f6 (50% rfd + 50% cow dung + zn and b as foliar spray) treatment but the lowest result given by f1 (no fertilizer) treatment (table 1-3). table 1. plant height of lentil as affected by micronutrient management in different growth stages of lentil growth and yield of lentil as influenced by zinc and boron management 36 treatments plant height (cm) 30 das 55 das 80 das harvest variety v1 14.44 26.52 32.59 34.57 v2 13.47 25.52 31.07 34.51 lsd(0.05) ns ns ns ns cv (%) 8.54 5.33 11.06 9.43 micronutrient (zn and b) management f1 13.11b 25.48 31.12ab 32.60b f2 13.92ab 25.52 31.27ab 33.53b f3 15.14a 25.79 30.90b 34.95ab f4 14.46ab 26.49 31.40ab 34.45ab f5 13.65b 26.03 32.60ab 34.60ab f6 13.46b 26.81 33.70a 37.09a lsd(0.05) 1.425 ns 2.588 3.424 cv (%) 8.48 6.11 6.75 8.23 interaction v1f1 13.37bcd 25.52ab 31.10abc 32.67b v1f2 14.27abcd 25.30ab 32.87ab 34.20ab v1f3 15.76a 26.98ab 32.80ab 35.50ab v1f4 15.06ab 27.27ab 31.63abc 34.23ab v1f5 14.92ab 26.41ab 33.47a 35.07ab v1f6 13.27bcd 27.65a 33.67a 35.73ab v2f1 12.86cd 25.43ab 31.15abc 32.53b v2f2 13.56bcd 25.74ab 29.67bc 32.87b v2f3 14.53abc 24.61b 29.00c 34.40ab v2f4 13.85abcd 25.71ab 31.17abc 34.67ab v2f5 12.37d 25.65ab 31.73abc 34.13ab v2f6 13.66bcd 25.97ab 33.73a 38.45a lsd(0.05) 2.015 2.709 3.660 4.842 cv (%) 8.48 6.11 6.75 8.23 note: ns= non-significant; v1: bari masur-8, v2: binamasur-8, f1: control (no fertilizer), f2: recommended fertilizer dose of n, p, k, and s (rfd) with zn as basal, f3: rfd with zn as foliar spray, f4: rfd with zn and b as foliar spray, f5: 50% rfd + 50% cow dung, f6 : 50% rfd + 50% cow dung + zn and b as foliar spray the highest 1000-seed weight (31.68 g) was recorded from the f2 (recommended fertilizer dose of n, p, k, and s (rfd) with zn as basal) treatment but the lowest result given by f3 (rfd with zn as foliar spray) treatment (table 3). the highest seed yield (2.62 t ha−1), straw yield (2.12 t ha−1) and biological yield (4.74 t ha−1) was recorded from the f3 treatment those similar to f6 treatment but the lowest result given by f1 treatment for most of the studied parameters (table 3). table 2. effect of variety and micronutrient management on growth and yield attributes of lentil treatments branches plant−1 (no.) shoot dry wright plant−1 (mg) pods plant−1 (no.) pod length (cm) seeds pod−1 (no.) variety v1 5.64 2837.17 55.42 1.17 1.71 v2 5.72 2665.83 48.54 1.18 1.73 lsd(0.05) ns ns ns ns ns cv (%) 15.38 22.46 16.76 34.08 32.98 37 kumar et al. micronutrient (zn and b) management f1 5.43b 2065.17c 47.53ab 1.19 1.73 f2 5.57b 2762.50abc 45.30b 1.18 1.72 f3 5.50b 2575.67abc 52.00ab 1.16 1.70 f4 5.43b 3238.33ab 49.17ab 1.15 1.62 f5 5.13b 2548.00abc 55.53ab 1.19 1.78 f6 7.03a 3319.33a 62.37a 1.17 1.78 lsd(0.05) 1.093 1158.84 15.439 ns ns cv (%) 15.97 34.97 24.66 6.73 29.46 interaction v1f1 5.73bc 1934.00 48.40ab 1.20 1.62ab v1f2 5.53bc 2348.33 50.53ab 1.16 1.70ab v1f3 5.20bc 2815.67 61.00ab 1.16 1.67ab v1f4 5.27bc 3318.00 53.93ab 1.15 1.70ab v1f5 5.47bc 3054.67 57.13ab 1.20 1.77ab v1f6 6.67ab 3552.33 61.53ab 1.17 1.79ab v2f1 5.13bc 2196.33 46.67ab 1.18 1.83a v2f2 5.60bc 3176.67 40.07b 1.21 1.73ab v2f3 5.80bc 2335.67 43.00ab 1.17 1.73ab v2f4 5.60bc 3158.67 44.40ab 1.15 1.53b v2f5 4.80c 2041.33 53.93ab 1.18 1.80ab v2f6 7.40a 3086.33 63.20a 1.17 1.77ab lsd(0.05) 1.546 ns 21.835 ns 0.273 cv (%) 15.97 34.97 24.66 6.73 29.46 note: ns= non-significant; v1 : bari masur-8, v2 : binamasur-8, f1 : control (no fertilizer), f2 : recommended fertilizer dose of n, p, k, and s (rfd) with zn as basal, f3 : rfd with zn as foliar spray, f4 : rfd with zn and b as foliar spray, f5 : 50% rfd + 50% cow dung, f6 : 50% rfd + 50% cow dung + zn and b as foliar spray hossain et al. (2020) reported 44% higher yield of lentil using micronutrient and the increased lentil yield might be associated with increased nodulation and nutrient uptake by the crop under micronutrient-applied treatments. significant effect of zn and b on plant height of lentil was reported by quddus et al. (2014), branches plant−1 by paul et al. (2019), shoot dry weight plant−1 by singh and bhatt (2013), pods plant−1, seeds pod−1, 1000-seed weight and seed yield by quddus et al. (2014) and biological yield by khurana and sanjay (2012). interaction of variety and micronutrient management the treatment combination of v2f6 (binamasur-8 and 50% rfd + 50% cow dung + zn and b as foliar spray) showed the highest plant height (38.45 cm), number of branches plant−1 (7.40), number of pods plant−1 (63.20), seed yield (2.91 t ha−1), and harvest index (58.65%) compared to that of other interactions whereas the highest number of seeds pod−1 (1.83) by v2f1 (binamasur-8 and no fertilizer), 1000-seed weight (34.87) by v1f1 (bari masur-8 and no fertilizer), straw yield (2.22 t ha−1 ) and biological yield (5.02 t ha−1) by v1f3 (bari masur-8 and rfd with zn as foliar spray) treatment combinations (table 1-3). the lowest parameters were recorded from v2f1 (binamasiur-8 and no fertilizer application) interactions having plant height (32.53 cm) and straw yield (1.63 t ha−1) compared to that of other interactions whereas the number of branches plant−1 (4.80) and harvest index (53.13%) by v2f5 (binamasur-8 and 50% rfd + 50% cow dung), number of pods plant−1 (40) by v2f2 (binamasur8 and recommended fertilizer dose of n, p, k, and s (rfd) with zn as basal), number of seeds pod−1 (1.53) by v2f4 (binamasur-8 and rfd with zn and b as foliar spray), 1000-seed weight (27.13) by v2f3 (binamasur-8 and rfd with zn as foliar spray), seed yield (1.96 t ha−1) and biological yield (3.69 t ha−1) by v1f4 (bari masur-8 and rfd with zn and b as foliar spray) treatment combinations (table 1-3). table 3. effect of variety and micronutrient (zn and b) management on seed weight and yield of lentil treatments 1000-seed wt. (g) seed yield (t ha−1) straw yield (t ha−1) biological yield (t ha−1) harvest index (%) growth and yield of lentil as influenced by zinc and boron management 38 variety v1 34.16a 2.37 1.94 4.31 54.95 v2 28.28b 2.47 1.97 4.43 55.77 lsd(0.05) 3.129 ns ns ns ns cv (%) 6.99 15.41 20.44 9.98 9.68 micronutrient (zn and b) management f1 31.60ab 2.15b 1.71b 3.86b 55.88 f2 31.68a 2.53a 2.01ab 4.54a 55.85 f3 30.22c 2.62a 2.12a 4.74a 55.22 f4 31.57ab 2.22b 1.91ab 4.13ab 54.08 f5 31.37ab 2.41ab 1.97ab 4.38ab 55.25 f6 30.88abc 2.57a 2.01ab 4.58a 55.90 lsd(0.05) 0.928 0.358 0.338 0.625 ns cv (%) 2.47 38.91 45.44 11.88 5.39 interaction v1f1 34.87a 2.09de 1.79abc 3.89bc 53.73a-d v1f2 34.57abc 2.64abc 2.13ab 4.78a 55.62a-d v1f3 33.30c 2.79ab 2.22a 5.02a 55.52a-d v1f4 34.77ab 1.96e 1.74bc 3.69c 53.32bcd v1f5 33.93abc 2.48a-d 1.79abc 4.27abc 58.36ab v1f6 33.50bc 2.24cde 1.96abc 4.20abc 53.16cd v2f1 28.33de 2.20cde 1.63c 3.83bc 58.03abc v2f2 28.80d 2.41a-e 1.89abc 4.29abc 56.07a-d v2f3 27.13e 2.45a-e 2.01abc 4.46abc 54.91a-d v2f4 28.37de 2.48a-d 2.07abc 4.56ab 54.83a-d v2f5 28.80d 2.35cde 2.15ab 4.49abc 53.13d v2f6 28.25de 2.91a 2.05abc 4.96a 58.65a lsd(0.05) 1.313 0.506 0.478 0.884 5.087 cv (%) 2.47 38.91 45.44 11.88 5.39 note: ns= non-significant; v1 : bari masur-8, v2 : binamasur-8, f1 : control (no fertilizer), f2 : recommended fertilizer dose of n, p, k, and s (rfd) with zn as basal, f3 : rfd with zn as foliar spray, f4 : rfd with zn and b as foliar spray, f5 : 50% rfd + 50% cow dung, f6 : 50% rfd + 50% cow dung + zn & b as foliar spray zinc being essential nutrient plays a significant role in stomatal regulation and reducing the tensions of less water by creating ionic balance in plants system (baybordi, 2006) and is involved in various physiological processes such as synthesis of protein and carbohydrates (yadavi et al., 2014). similarly, b application improves growth, and enhances stress tolerance in plants and improves grain production (hussain et al., 2012). both zn and b plays an important role in the basic plant functions like photosynthesis, protein and chlorophyll synthesis (cakmak, 2008). conclusion the varieties showed similar performance on most of the parameters except 1000-seed weight. foliar application of zn and b showed the potentiality to increase seed yield and hence application of zn and b reflected their effectiveness on lentil cultivation. the variety binamasur-8 with 50% recommended fertilizer dose + 50% cow dung + zn and b as foliar spray could bring maximum yield (2.91 t ha−1) of lentil. as the experiment was conducted on one year and in one agro-ecological zone (aez), it is suggested to conduct more study in longer period of times and in different aez before final recommendation. acknowledgement the author gratefully acknowledged the ministry of science and technology, govt. of the people’s republic of bangladesh for providing financial support to conduct the study. 39 kumar et al. references arif, m., m.a. chohan, s. ali and s. khan. 2006. response of wheat to foliar application of nutrients. j. agric. biol. sci. 1: 30-34. baybordi, a. 2006. effect of fe, mn, zn and cu on the quality and quantity of wheat under salinity stress. j. water soil sci. 17: 140-150. bbs (bangladesh bureau of statistics). 2021. statistical yearbook of bangladesh. bangladesh bureau of statistics. statistics division, ministry of planning. government of the people's republic of bangladesh. bhatty, r.s. 1988. composition and quality of lentil (lens culinaris medik.): a review. can. inst. food sci. technol. j. 21: 144-160. cakmak, i. 2008. enrichment of cereal grains with zinc: agronomic or genetic biofortification. plant soil. 302: 1– 17. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. 2nd edn. irri, los banos, languna, philippines. pp. 62-74. hossain, m.a., a. quddus, k. alam, h.m. naser, b. anwar, f. khatun, h. rashid, f. khatun and a. siddiky. 2020. application of zinc, boron, and molybdenum in soil increases lentil productivity, nutrient uptake, and apparent balance. can. j. soil sci. 101: 113-124. hussain, m., m.a. khan, m.b. khan, m. farooq and s. farooq. 2012. boron application improves the growth, yield and net economic return of rice. rice sci. 19(3): 259-262. islam, m.m., m.r. karim, m.m.h. oliver, t.a. urmi, m.a. hossain and m.m. haque. 2018. impacts of trace element addition on lentil (lens culinaris l.). agronomy. 8(7): 100. khatun, s., m.i. khalil and m. roknuzzaman. 2021. yield performance of bina developed lentil varieties, bangladesh j. nuclear agric. 35: 183-187. khurana, m.p.s. and a. sanjay. 2012. comparative efficiency of borax and granubor as boron fertilizers for lentil and soybean grown on alluvial alkaline soils. j. plant nutr. 35(14): 2145-2155. nasiri, y., s. zehtab-salmasi, s. nasrullahzadeh, n. najafi and k. ghassemi-golezani. 2010. effects of foliar application of micronutrients (fe and zn) on flower yield and essential oil of chamomile (matricaria chamomilla l.). j. med. plants res. 4(17): 1733 -1737. panhwar, q.a., o. radziah, y.m. khanif and u.a. nahar. 2011. application of boron and zinc in the tropical soils and its effect on maize (zea mays l.) growth and soil microbial environment. aust. j. crop. sci. 5(12): 1649-1654. paul, s., t.s. roy, r. chakraborty, m. roy and s.c. sarker. 2019. growth performance of lentil by the effect of irrigation and boron splitting as foliar application, bangladesh agron. j. 22(2): 139-150. quddus, m.a., h.m. naser, m.a. hossain and m.a. hossain. 2014. effect of zinc and boron on yield and yield contributing characters of lentil in low ganges river floodplain soil at madaripur, bangladesh. bangladesh j. agril. res. 39(4): 591-603. singh, a.k. and b.p. bhatt. 2013. effect of foliar application of zinc on growth and seed yield of late-sown lentil (lens culinaris). indian j. agric. sci. 83(6): 622-626. togay, n., y. togay, m. erman and f. cig. 2015. effect of fe (iron) and mo (molybdenum) application on the yield and yield parameters of lentil (lens culinaries medic.). legume res. 38(3): 389-393. yadavi, a., r.s. aboueshaghi, m.m. dehnavi and h. balouchi. 2014. effect of micronutrıents foliar application on grain qualitative characteristics and some physiological traits of bean (phaseolus vulgaris l.) under drought stress. indian j. fund. appl. life sci. 4(4): 124-131. zaman, m.s.u., m.a. hossain, m.j. alam, a.k.m.m. alam, m.o. ali, d. sarker and a. sarker. 2022. ‘bari masur-8’: a high-yielding and biofortified lentil cultivar in bangladesh. j. plant regist: 16(3): 504-510. bangladesh agron. j. 2023, 26(1): 104-111 influence of agronomic managements on growth and yield of boro rice j.c. roy1*, p.k. biswas2, m.s. islam2 and m. h. mahmud3 1japan tobacco international, kushtia, bangladesh 2department of agronomy, sher-e-bangla agricultural university dhaka-1207, bangladesh, 3project implementation unit-barc, national agricultural technology program-phase-ii project, dhaka, bangladesh. *corresponding author, email: jibanroyjc05@gmail.com (received: 15 april 2023, accepted: 24 september 2023) keywords: agronomic management, boro rice, growth, yield abstract the study was carried out at sher-e-bangla agricultural university, dhaka from december 2018 to april 2019, to find out the agronomic practices on the growth and yield of boro rice. the trial was conducted with two rice varieties namely v1 (brri dhan84) and v2 (brri hybriddhan5), and 5 different agronomic practices such as m0 (no management), where variety in maim-plot and management practices in sub-plot. the results showed significant variations in weed severity, and l yield of boro rice. specific observations included plants reaching heights of 24.81 cm, 51.56 cm, 86.71 cm, and 119.21 cm at 20, 45, 70 days after transplanting (dat), and at harvest, respectively. v2 exhibited a higher grain yield (5.36 t ha−1) but a reduced straw yield (4.97 t ha−1) compared to v1. generally, regardless of the agronomic practices, brri dhan84 exhibited greater plant height, except under the 'no management' practice. the grain yield (6.70 t ha−1) was obtained with m6, and the maximum straw yield (6.55 t ha−1) to m4. the interaction effects showed that highest grain yield (7.35 t ha−1) from v2m6, while with v1m0.the most significant yield reduction for brri dhan84 was 84% with no management and 80% with no fertilizer, while brri hybriddhan5 showed a 71% reduction under similar conditions. introduction rice is the primary crop in bangladesh, occupying 75% of the total cropped area, with 92% of farmers cultivating it (rekabder, 2004). approximately 75% of all cropped regions and over 80% of irrigated zones are dedicated to rice (brkb, 2017). while bangladesh boasts an average rice yield of 3.26 t ha−1 (bbs, 2022), its productivity lags behind countries like china, japan, and korea, all of which have average yields of t ha−1 (fao, 2009). different fertilization approaches can influence plant growth, maturation, size, phytochemical content, and seed properties (mevi schütz et al., 2003). water management, particularly during the boro season's flowering stage, affects water use efficiency (maity and sarkar, 1990). water shortages at various growth stages can severely impact grain yield (patel, 2000). furthermore, weeds pose the most significant challenge to rice yield, with global yield losses to pests estimated at 40%. of these losses, weeds are responsible for a staggering 32% (rao et al., 2007). effective agronomic strategies profoundly influence rice growth and yield. yield decreases are often due to suboptimal weed, nutrient, and irrigation management. consequently, comprehensive management techniques are crucial for optimal rice production in bangladesh. however, many bangladeshi farmers spend excessive time and effort on weed control while neglecting proper fertilization and irrigation. its objectives encompass comparing two boro rice agronomic managements on growth and yield of boro rice 105 varieties, evaluating individual agronomic techniques on rice growth, and examining the combined impact of variety and agronomic practices on boro rice performance. materials and methods the experiment was carried out at sher-e-bangla agricultural university's field in sher-ebangla nagar, dhaka. this site is positioned at a latitude of 23 º74´n and a longitude of 90º35´e, and it stands 8.2 meters above sea level. the soil here originates from "the modhupur tract" or aez28, as categorized by fao in 1988. this topsoil has an olive-gray, silty clay texture, dotted with distinct dark yellowish-brown spots. it has a ph of 5.6 and contains 0.45% organic carbon.the trial was carried in out in a split-plot design with three replications where variety (brri dhan84 and brri hybriddhan5) in main-plot and management practices in sub-plot.. on variety, and seven different management i.e., no managements(m0), no weeding, (m1), no fertilizer application, but all other managements (m2), no irrigation in reproductive and ripening stage, but all other managements (m3), no insecticides, but all other managements (m4), no fungicides/bactericides, but all other managements (m5), complete managements (m6) the var. brri dhan84, on average, stands between 90-96 cm tall during its ripening stage, bearing medium fine, white grains. it completes its life cycle in approximately 140-145 days and produces an average grain yield of 6.0-6.5 t ha−1, as reported by brkb in 2017. the experiment area received fertilization as per recommended methods: 200 kg n, 80 kg p2o5, 125 kg k2o, 20 kg s, and 10 kg zn. urea was applied in three portions while other fertilizers were added during the final land preparation. crop management was based as per need. various metrics such as plant height, leaf area index (lai), number effective non-effective tillers hill–1 and panicle length were measured. leaf area index calculated by foliage from 5 hills canopy, measuring the leaf area per plot and dividing it by the plot land surface area. grains were categorized as filled or unfilled, counted the data from 10 panicles per plot. the weight of 1000 grains were measured at 12% moisture content. both grain and straw yields were calculated from each plot's converted to as t ha−1. biological yield was calculated with the following formula: biological yield = grain yield + straw yield. harvest index was calculated as: hi = economic yield (grain weight) biological yield (total dry weight)  100 finally, the data was analyzed for any significant variations between the treatments. by using duncan’s multiple range test at a 5% probability level gomez and gomez (1984). results and discussion plant height plant height showed numeric differences at 20, 45, and 70 dat, and significant differences at harvest for both brri dhan84 and brri hybriddhan5 (table 1). the tallest plants at 45, 70 dat and at harvest were from v1 (brri dhan84) with heights of 24.81 cm, 51.56 cm, 86.71 cm, and 119.21 cm respectively. conversely, the shortest plants were from v1 (brri hybriddhan5) with heights of 25.28 cm, 49.53 cm, 79.61 cm, and 104.08 cm. the variations in plant height were attributed to the inherent varietal characteristics. at 20, 45, 70 dat, and at harvest, the tallest plants were observed under m6 (recommended management) with heights of 25.65 cm, 53.713 cm, 87.26 cm, and 118.15 cm respectively. in contrast, the shortest plants, with heights of 22.73 cm, 39.76 cm, 66.95 cm, and 93.88 cm respectively, were recorded under m0 (no management). considering the interaction between variety and management, the tallest plants at 20, 45, 70 dat, and at harvest were from v1m6 (brri dhan84 + recommended 106 roy et al. management) with respective heights of 25.89 cm, 55.6 cm, 89.32 cm, and 127.4 cm. the shortest plants, on the other hand, were from v1m0 (brri hybriddhan5 + no management) with heights of 22.92 cm, 36.93 cm, 61.28 cm, and 90.6 cm, respectively. leaf area index the leaf area index (lai) showed numeric variation at 20 and 45 dat and significant variation at 70 dat for both brri dhan84 and brri hybriddhan5 (table 1). table 1. effect of variety, agronomic managements, and treatment interaction on plant height (cm) and leaf area index (lai) of boro rice treatments plant height (cm) leaf area index (lai) 20 dat 45 dat 70 dat at harvest 20 dat 45 dat 70 dat at harvest variety v1 24.81 51.56 86.71 119.22 0.09 b 3.30 a 6.86 a 7.06 a v2 25.29 49.54 79.61 104.08 0.10 a 2.35 b 6.44 b 5.20 b se ± 0.45 0.97 1.21 1.69 0.01 0.2 0.18 1.52 cv (%) 17.00 16.29 8.97 8.26 33.41 22.85 8.78 80.43 agronomic managements m0 22.74b 39.76c 66.95b 93.88c 0.09 a 1.30 b 1.67 c 2.08 d m1 23.22b 41.96c 71.25b 105.17b 0.09 a 1.37 b 3.25 c 3.74 cd m2 26.27a 58.87a 88.44a 116.27a 0.12 a 3.81 a 5.91 b 4.67 bc m3 25.56ab 52.52b 90.18a 115.83a 0.10 a 3.28 a 9.30 a 8.98 a m4 26.02ab 53.98b 86.85a 114.62a 0.09 a 3.27 a 8.70 a 7.68 a m5 25.88ab 53.05b 91.19a 117.63a 0.10 a 3.33 a 8.34 a 6.76 ab m6 25.66 53.71 87.26a 118.15a 0.11 a 3.43 a 9.40 a 9.00 a se 1.03 1.12 1.40 1.69 0.01 0.26 0.51 0.61 cv (%) 11.48 5.49 6.12 5.46 31.48 33.66 27.48 35.98 combined influence of variety and agronomic managements v1m0 22.54 b 42.58 de 72.61 d 97.16 de 0.08 abc 1.72 cde 2.13ef 2.95 ef v1m1 22.87 b 38.94 ef 70.94 d 111.20 b 0.07 c 1.11 de 2.51ef 3.17 ef v1m2 26.50 ab 60.04 a 92.60 ab 125.90 a 0.11 abc 4.83 a 6.68bcd 5.54 cde v1m3 27.16 ab 53.92 bc 94.82 a 123.53 a 0.10 abc 3.61 ab 8.6ab 9.12 abc v1m4 24.94 ab 54.79 bc 91.46 ab 124.80 a 0.08 abc 3.71 ab 9.62ab 9.64 ab v1m5 23.75 ab 55.04 bc 95.22 a 124.53 a 0.07 bc 3.95 ab 8.65ab 8.05 abc v1m6 25.89 ab 55.60 abc 89.32 abc 127.40 a 0.12 ab 4.15 ab 9.84a 10.98 a v2m0 22.92 b 36.93 f 61.28 e 90.60 e 0.09 abc 0.87 e 1.22f 1.21 f v2m1 23.56 ab 44.98 d 71.56 d 99.13 cde 0.11 abc 1.62 cde 3.99def 4.31 def v2m2 26.03 ab 57.70 ab 84.28 bc 106.63 bcd 0.12 ab 2.78 bc 5.14cde 3.80 def v2m3 23.95 ab 51.11 c 85.53 bc 108.13 bc 0.10 abc 2.94 bc 10a 8.85 abc v2m4 27.10 ab 53.16 bc 82.23 c 104.43 bcd 0.08 abc 2.82 bc 7.77abc 5.72 cde v2m5 28.01 a 51.04 c 87.16 abc 110.73 b 0.13 a 2.72 bc 8.02abc 5.47 cde v2m6 25.42 ab 51.82 c 85.20 bc 108.90 bc 0.10 abc 2.71 bcd 8.96ab 7.02 bcd se= 1.13 1.09 1.99 2.39 0.01 0.37 0.72 0.86 cv (%) 11.48 5.49 6.12 5.46 31.48 33.66 27.48 35.98 in a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability by dmrt test.v1: brri dhan84, v2: brri hybriddhan5; m0: no management, m1: no weeding, but all other managements, m2: no fertilizer application, but all other managements, m3: no irrigation in reproductive and; ripening stage, but all other managements, m4: no insecticides, but all other managements, m5: no fungicides/bactericides, but all other managements, m6: complete managements. agronomic managements on growth and yield of boro rice 107 the highest lai values at 20, 45, and 70 dat were 0.09, 3.3, and 6.9 respectively, was recorded from v1 (brri dhan84). on the other hand, the lowest values were 0.1, 2.35, and 6.44 respectively from v2 (brri hybriddhan5). different agronomic managements showed significant impacts on the lai at 20, 45, and 70 dat. specifically, the highest lai values were observed under m6 (recommended management) with values of 0.11, 3.43, 9.40, and 9.00 respectively. conversely, the lowest lai values 0.09, 1.30, 1.67, and 2.08 respectively, were recorded under m0 (no management). the interaction between variety and management revealed the highest lai values at 20, 45, 70 dat, and harvest from v1m6 (brri dhan84 + recommended management) with 0.12, 4.15, 9.84, and 10.98 respectively. the lowest values were from v2m0 (brri hybriddhan5 + no management) with values of 0.09, 0.87, 1.22, and 1.21, respectively. effective tillers hill−1 for brri dhan84 and brri hybriddhan5, the number of effective tillers per hill at harvest showed notable variation (table 2). table 2. effect of variety, agronomic managements, and interaction on number of effective tillers, non-effective tillers hill−1, panicle length, number of filled grains panicle–1 and number of unfilled grains panicle–1 of boro rice treatments number of effective tillers hill−1 number of noneffective tillers hill−1 panicle length (cm) number of filled grains panicle−1 number of unfilled grains panicle−1 variety v1 10.83 a 0.26 b 25.91a 123.81 26.00 v2 7.33 b 0.54 a 24.36a 161.24 16.29 se ± 0.44 0.02 1.59 51.86 14.64 cv (%) 3.87 4.63 20.49 12.05 3.40 agronomic managements m0 5.60 d 0.17 a 22.43b 101.17c 8.50d m1 8.20 bc 0.50 a 24.68b 146.50ab 15.17cd m2 7.27 cd 0.50 a 24.04b 125.50bc 20.50bc m3 10.90 a 0.37 a 24.77b 143.17ab 26.17ab m4 10.90 a 0.53 a 25.94ab 165.17a 22.67ab m5 9.90 b 0.40 a 28.65a 155.50a 28.17a m6 10.80 a 0.33 a 25.44ab 160.67a 26.83ab se ± 0.59 0.09 0.87 101.17c 8.50d cv (%) 4.21 14.58 12.45 146.50ab 15.17cd combined influence of variety and agronomic managements v1m0 7.53 de 0.02 cde 22.86 b 93.00f 7.67f v1m1 8.93 cd 0.60 bc 24.98 b 134.67cde 15.67def v1m2 8.80 cd 0.40 b-e 23.76 b 98.00f 20.00cd v1m3 12.33 ab 0.20 de 25.02 b 123.67def 36.33ab v1m4 14.00 a 0.07 e 26.37 b 143.00bcde 27.33bc v1m5 11.20 bc 0.13 e 32.52 a 135.00cde 39.33a v1m6 13.00 ab 0.13 e 25.86 b 139.33cde 35.67ab v2m0 3.67 f 0.07 e 21.99 b 109.33ef 9.33ef v2m1 7.47 de 0.40 b-e 24.39 b 158.33abcd 14.67def v2m2 5.73 ef 0.6 bc 24.31 b 153.00abcd 21.00cd v2m3 9.47 cd 0.53 bcd 24.52 b 162.67abc 16.00def v2m4 7.80 de 1.00 a 25.50 b 187.33a 18.00cde v2m5 8.60 d 0.67 ab 24.79 b 176.00ab 17.00def v2m6 8.60 d 0.53 bcd 25.02 b 182.00a 18.00cde se ± 0.95 0.09 0.87 8.12 2.22 cv (%) 4.21 14.58 12.45 14.55 26.83 in a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability. additional details are as table 1. 108 roy et al. brri dhan84 (v1) had a higher with averaging 10.83, while brri hybriddhan5 (v2) averaged at 7.33. various agronomic practices and their interaction with different varieties caused significant differences. the highest average (10.90) from m4 (all managements except insecticides), with the least (5.60) under m0 (no management). the combined practice of brri dhan84 and m4 showed the highest of 14.00, but when brri hybriddhan5 was combined with m0, (3.65). non-effective tillers hill–1 the number of non-effective tillers per hill at harvest also varied between brri dhan84 and brri hybriddhan5, influenced by agronomic practices and rice varieties (table 2). brri hybriddhan5 (v2) recorded a higher of 0.54, in contrast to brri dhan84's (v1) 0.26. m4 practice led to the highest average of 0.53, while m0 resulted in the least at 0.17. the combination of brri dhan84 with m4 resulted in the peak count of 1.00. conversely, brri hybriddhan5 combined with m0 marked the lowest at 0.07 in brri dhan84 combinations. length of panicle the length of the panicle varied between brri dhan84 and brri hybriddhan5 where brri dhan84 (v1) had a longer panicle length of 25.91 cm, while brri hybriddhan5 (v2) had a shorter length of 24.36 cm (table 2). uzzaman et al., (2015) was also found significant differences in panicle length of 16 rice varieties under sri. different agronomic practices also influenced panicle length, with the longest (28.65 cm) observed under m5 and the shortest (24.03 cm) in m2 (table 2). the longest panicle in the interaction effect of variety and agronomic management was 32.52 cm from v1m5 and the shortest (21.99 cm) from v2m0 (table 2). number of filled grains per panicle there was a numerical variation in the number of filled grains per panicle where brri hybriddhan5 (v2) had a higher (161.24), whereas brri dhan84 (v1) had 123.81 (table 2). ahmed et al., (1997) and uzzaman et al., (2015) reported varying percentages of filled grains among different rice varieties. agronomic practices also led to significant differences, with the highest no. (165.17) was observed under m4 and the lowest (101.17) in m0 (table 2). for the interaction of variety and agronomic practices, the highest and lowest counts were observed from v2m4 (174.67) and v1m0 (93.00) respectively (table 2). number of unfilled grains per panicle the number of unfilled grains per panicle also varied between the two varieties. brri dhan84 (v1) had a higher (26.00), while brri hybriddhan5 (v2) recorded 16.29 (table 2). uzzaman et al., (2015) was found significant differences in panicle length 16 rice varieties under sri. agronomic practices influenced this count, with the highest (28.17) observed under m5 and the lowest (8.50) in m0 (table 2). for the interaction between variety and agronomic practices, counts ranged from a high of 39.33 (v1m5) to a low of 7.65 (v1m0) (table 2). the highest number of unfilled grains per panicle (39.33) was noted in v1m5 (brri dhan84 without fungicides/bactericides) followed by v1m6 (35.67). conversely, v1m0 (brri dhan84 with no management) registered the lowest (t 7.65) followed by v1m1, v2m1, v2m3, and v2m5 (table 2). weight of 1000grains the weight of 1000grains didn't show much variation between brri dhan84 and brri hybriddhan5, but there were significant differences among the various agronomic managements and their interactions (table 3). the higher t weight for 1000 grains (26.70 g) from m6 agronomic managements on growth and yield of boro rice 109 (recommended management), closely followed by m5, m4, and m3. the v2m6 combination (brri hybriddhan5 + recommended management) had the maximum 1000 -grains (31.97 g) close to v2m4(31.88 g) whereas v1m0 recorded the lightest at 20.17 g. table 3. effect of variety, agronomic managements, and interaction on weight of 1000 grains (g), grain yield (t ha–1), straw yield (t ha–1), biological yield (t ha–1) and harvest index of boro rice treatments weight of 1000 grains (g) grain yield (t ha−1) straw yield (t ha−1) biological yield (t ha−1) harvest index (%) variety v1 21.71b 4.31 5.22 9.85 45.41 v2 31.10a 5.36 4.97 10.01 48.62 se ± 1.41 0.37 0.22 0.63 5.08 cv (%) 0.33 24.69 9.31 20.64 34.99 agronomic managements m0 25.68b 1.68b 2.22 c 3.90 c 43.02 b m1 25.70b 1.85b 4.02 bc 8.57 b 52.15 ab m2 25.88b 1.98b 4.31 bc 6.29 bc 29.52 c m3 26.01ab 6.28a 6.50 a 12.78 a 49.20 ab m4 26.14ab 6.02a 6.55 a 12.57 a 49.78 ab m5 26.57ab 6.69a 5.47 ab 12.16 a 55.16 a m6 26.70a 6.70a 6.53 a 13.23 a 50.26 ab se ± 0.37 0.28 0.50 0.64 2.77 cv (%) 3.61 20.73 31.94 20.92 19.09 combined influence of variety and agronomic managements v1m0 20.17d 1.00f 2.36 ef 4.35 ef 44.34 ab v1m1 23.55c 3.71cd 3.62 def 7.92 cd 53.84 a v1m2 21.60d 1.85ef 4.77 bcd 5.81 def 17.99 c v1m3 21.65d 5.53b 6.36 abc 12.52 a 49.13 ab v1m4 23.62c 5.67ab 7.37 a 13.24 a 47.41 ab v1m5 23.66c 6.05ab 5.21 bcd 11.62 ab 55.62 a v1m6 23.75c 6.34ab 6.87 ab 13.50 a 49.50 ab v2m0 30.18b 1.51ef 2.07 f 3.44 f 41.69 b v2m1 30.60ab 3.39cd 4.43 cd 9.22 bc 50.46 ab v2m2 30.16b 2.97de 3.85 def 6.78 cde 41.04 b v2m3 31.45ab 7.04ab 6.64 ab 13.04 a 49.26 ab v2m4 31.88a 6.36ab 5.74 bcd 11.90 ab 52.15 ab v2m5 31.47ab 7.33a 5.73 bcd 12.70 a 54.69 a v2m6 31.97a 7.35a 6.34 abc 12.96 a 51.02 ab se ± 0.37 0.39 0.50 0.64 2.77 cv (%) 3.61 20.73 31.94 20.92 19.09 in a column mean values having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly as per 0.05 level of probability. additional details are as table 1. grain yield the grain yield didn't show any significant differences between brri dhan84 and brri hybriddhan5 but varied significantly among the different agronomic managements and their interactions (table 3). m6 (recommended management) yielded the highest grain yield, 6.70 t ha−1, 110 roy et al. comparable to m5, m4, and m3 while m0 had the least yield. the combination v2m6 resulted in the highest grain yield, while v1m0 recorded the lowest. straw yield straw yield showed variations between brri dhan84 and brri hybriddhan5, with significant differences appearing in different agronomic managements and their interactions (table 3). v1 (brri dhan84) produced a higher straw yield of 5.22 t ha−1 compared to v2 (4.97 t ha−1). the highest straw yield was recorded from m4, a management strategy without insecticides but including all other management practices. the v1m4 combination recorded the highest straw yield, while v2m0 noted the lowest. biological yield biological yield per hectare varied slightly between brri dhan84 and brri hybriddhan5 but showed significant changes depending on agronomic managements and interaction effects (table 3). v2 recorded the highest biological yield of 10.01 t ha−1, followed by v1 (9.85 t ha−1). the combination v1m4 yielded the highest biological yield, whereas v2m0 had the least. harvest index the harvest index showed significant differences based on variety, agronomic managements, and their interaction (table 3). v2 (brri hybriddhan5) had the maximum harvest index (48.62%), followed by v1(45.91%). among management strategies, m5 recorded the highest harvest index, while m2 had the lowest. when considering combinations, v1m5 produced the maximum harvest index, with v1m2 registering the minimum. conclusion based on the results presented, it's evident that agronomic management, the absence of fertilization, and lack of weeding have a substantial negative impact on grain yield. in particular, rice var. brri dhan84 exhibited a yield reduction of 84% with no management, 72% without fertilizer, and 43% without weeding. similarly, brri hybriddhan5 showed a decrease of 83% in yield without management, 67% without fertilizer, and 62% without weeding. however, further studies need to be conducted across different agro-ecological zones, incorporating more varieties, and varying agronomic practices. references ahmed, m. r., m.a. rashid, m.s. alam, k.a. billah and f. jameel. 1997. performance of eight transplant aman rice varieties under irrigated conditions. bangladesh rice j. 8(1 &2): 43-44. bbs. 2022. bangladesh bureau of statistics. statistical year book of bangladesh. bangladesh bureau of statistics. ministry of planning govt. people’s republic of bangladesh, dhaka, bangladesh pp.133135. brkb. 2017. bangladesh rice knowledge bank. retrieved from http://knowledgebank-brri.org/brri-ricevarieties/aus-rice-varieties.php brri. 1998. bangladesh rice research institute. bangladesh rice res. lnst. joydebpur, gazipur. fao. 1988. food and agriculture organization. production year book. food and agricultural of the united nations rome, italy, p.42: 190-193. fao. 2009. food and agriculture organization. fao production yearbook, food and agriculture organization, rome, italy, p.56-77. about:blank about:blank agronomic managements on growth and yield of boro rice 111 gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley pub. new york. maity, s. p and m. k. sarkar. 1990. influence of different water management practices on the yield and total evapotranspiraiton of paddy under different atmospheric evaporative demand. oryza. 27(3): 279281. mevi schütz j., m. goverde and a. erhardt. 2003. effects of fertilization and elevated co2 on larval food and butterfly nectar amino acid preference in coenonympha pamphilus l. behavioral ecol. and sociobiol. 54: 36–43. patel, j.r. 2000. effect of water regimes, variety and blue-green algae on rice (oryza sativa). indian j. agron. 45(1): 103-106. rao, a.n., d.e. johnson, b. sivaprasad, j.k. ladha and a.m. mortimer. 2007. weed management in direct seeded rice. adv. agron. 93: 153-255. rekabder, m.f.h. 2004. dhan chaser nana katha. krihikatha. 64(2): 3940. uzzaman, t., r. k. sikder, m. i. asif, h. mehraj and a. f.m. j. uddin. 2015. growth and yield trial of sixteen rice varieties under system of rice intensification. sci. agric. 11(2): 81-89. bangladesh agron. j. 2023, 26(1): 84-95 determination of economic nitrogen rate for transplanted aus rice varieties of bangladesh munmun akter1, md. khairul alam bhuiyan2 and sheikh muhammad masum1* 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2agronomy division, bangladesh rice research institute *corresponding author, email: smmasum607@yahoo.com (received: 24 july 2023, accepted: 28 september 2023) keywords: rice, nitrogen, nitrogen uptake, nitrogen use efficiency, yield abstract a field experiment was conducted at the agronomy field, bangladesh rice research institute, gazipur, dhaka, from april to september 2019 to determine the economic nitrogen rates for popular transplanted aus varieties. the experiment was carried out in a randomized complete block design (rcbd), with two factors. factor a: three varieties asbr26, brri dhan48, and brri dhan82; and factor b: five levels of nitrogen rates as0, 40, 60, 80, 100 kg ha−1. the experimental data show the individual effect of variety and nitrogen (n) rate was significant in the case of n concentration, n uptake in grain and straw, and nitrogen harvest index (nhi). overall, increasing n rate increases grain and straw's concentration irrespective of varieties. but higher n concentration and uptake were observed in the n rate of n60-n100 kg ha−1 in all varieties. among the varieties, brri dhan82 observed higher n uptake (61.23 kg ha−1) in grain. higher total n uptake was also observed in brri dhan48 at 80 kg n ha−1. nhi ranged from 55 to 72 % in different n levels, indicating 55 to 72% of the absorbed n translocated to the grains, and 45% to 32% remained in the dry matter within varieties. the estimated economic nitrogen dose for maximum yield was determined by regression analysis, and found that n rates of br26, brri dhan48, and brri dhan82 were 97, 95, and 55 kg ha−1, respectively. the findings of this study indicated that the response of different n rates on three aus varieties was linear up to 80 kg n ha−1 might be owing to better n uptake that made yield increase after that decreasing. introduction rice (oryza sativa l.) belongs to the family poaceae, it’s the most important cereal crop in the developing world and the main source of carbohydrates for the people of bangladesh, and it is the staple food of more than half of the people in the world (brri, 2021). about 90% of annual rice is produced and consumed in asia. the average yield in asia is lower than the global mean yield (haider, 2018). about 35-60% world's population derives most of its calories from rice (tayefe et al., 2014). the possible way to meet this increased demand is by improving rice yield hectare−1 (liu et al., 2016). bangladesh is the 3rd largest rice-producing country in the world (usda, 2020). about 75% area and over 80% of the total irrigated area of bangladesh is covered by rice (nasim et al., 2017). bangladesh's aus rice (summer rice) is a significant crop for drought-prone, low-waterrequiring environments. aus is usually planted in march-april and harvested in june-july, and the climate is practically combined with hot summer (march-may). aus rice occupies about 12.53% of the total cultivable area from where modern varieties cover 10.67%, local varieties cover 1.86 %, and 7.49% of the total production comes from aus rice, where modern varieties cover 6.87% and local varieties cover 0.62%. in bangladesh, the current status of the total area and production of aus rice is 1.08 million ha and 2.71 million mt (bbs, 2021). economic nitrogen rate for transplanted aus rice 85 nitrogen (n) fertilizer is required to grow and develop rice and grain production. n fertilizer is the main input in rice production and the optimum rate and profitability of management during the application and stability of the production system (djaman et al., 2018). improving leaf n concentration, photosynthetic rate, delaying leaf senescence, and increasing dry matter for grain filling, n helps to increase rice productivity (hasegawa et al., 1994). during the aus season, deep placement of fertilizer above 52 and 78 kg n ha−1 had no significant effects on grain yields but reduced n recovery (islam et al., 2016). n can improve panicle size and grain weight and reduce spikelet sterility (fageria, 2009). the application of n fertilizer in rice has also been reported to significantly increase the grain and straw n uptake and n use efficiency (hassan et al., 2009). balanced fertilization is more important for realizing potential grain yield and nutrient uptake than a single application of fertilizer, particularly n (talashilker and vimol, 1986). farmers generally apply more fertilizers than the recommended amount with the idea that using n will always increase the yield, which can result in change, negatively affect the sustainability of the production system, and increase production costs (fan et al., 2012). on the other hand, the application of excess n can result in groundwater pollution, increased production costs, reduced yields, environmental pollution (djaman et al., 2018), and vegetative growth, which makes the plant susceptible to insects, pests, and diseases and ultimately reduces yield (chamely et al., 2015). the maximum output of rice was recorded due to the application of 90 to 250 kg n fertilizer ha−1 (meena et al., 2003). nitrogen fertilizers are considered to have dominant influences on different agronomic characteristics of rice, such as plant height, tiller number, filled grains panicle−1, spikelet panicle−1, grain yield, straw yield, biological yield, harvest index, etc. nitrogen also influences the interception of sunlight, leaf area index (lai), crop growth rate, total dry matter production (tdm), and n uptake (nup) to the plant. under these circumstances, it is essential to determine the n-responsive stages of plant growth to ensure its maximum requirement to utilize the applied n effectively. moreover, an economic n rate is required for the farmers to get maximum profit. nitrogen fertilizer varies in different locations, ecosystems, and different varieties depending on the initial n status of the soil (masum et al., 2008) a suitable combination of variety and rate of n is required for better yield. therefore, the research objectives were to find the performance of t. aus rice varieties in different n levels and the economic n rate of t. aus rice varieties. materials and methods the experiment was conducted at the experimental farm of bangladesh rice research institute in aus season (summer rice) during the period from april to august 2019. the experimental location's climate is subtropical and characterized by heavy rainfall from april to september and scanty rainfall from october to march, with an average annual rainfall of 2000 mm. the soil of the experimental site belongs to the order inceptisols in the usda soil classification system. before the initiation of the experiment, soil samples from the top layer (20 cm) were collected and analyzed. the soil was silty clay loam in texture having ph 6.45, organic matter 1.54 (%), total n .014% (kjeldahl digestion method), available p 24.65 ppm, exchangeable k 0.18 (me/100 g soil) and available s 19.55 ppm. five rates (0, 40, 60, 80, and 100 kg ha-1) of n were tested on three high-yielding rice varieties (br26, brri dhan48, and brri dhan82). sprouted seeds were sown in the wet nursery bed on 10 april 2019. proper care was taken to raise healthy seedlings in the seedbed. weeding irrigation was done when was necessary. the experiment was laid out in 2 factors randomized complete block design with three replications. there were 45 unit plots in the experiment. each replication was divided into 15 unit plots where the treatment combinations were allocated at random. the size of each unit plot was (2.5 m x 4.0 86 masum et al. m =10 m2). the spacing between block to block and plot to the plot was 0.6 m and 0.4 m, respectively. the n was applied as urea in three equal splits: the first at the time of final land preparation, the second at maximum tillering stage and the third at panicle initiation. all the treatments received an equal amount of phosphorus (p), potassium (k), and sulfur (s) fertilizers and applied as basal. the application of fertilizer in the experiment is shown in table 1. table 1. application of fertilizer in the experimental plot treatment fertilizer (kg ha−1) application of fertilizer in the experimental plot (g 10 m⁻2) total 1st installment 2nd installment 3rd installment n0 n0 0 0 0 0 n1 n40 87 29 29 29 n2 n60 130 43.3 43.3 43.3 n3 n80 174 58 58 58 n4 n100 217 72.3 72.3 72.3 tsp 53 53 53 0 0 mop 82 82 82 0 0 gypsum 28 28 28 0 0 twenty days old seedlings were transplanted on 30 april 2019. in each plot, spacing (plant to plant and row to row) was 20 x 20 cm with two seedlings hill−1. the field was investigated occasionally to detect the visual difference between the treatment and any infestation by weeds, insects, and diseases to minimize considerable losses by pests. experimental data collection began at 15 days after transplanting and continued until harvest. the necessary data on yield contributing characters were collected from twelve selected hills (2 x 2) x 3 from each plot in the field, and at the harvest plot, yield was harvested from a 5 m2 plot and adjusted to 14% moisture content expressed as t ha−1. after harvest, grain and straw were taken from respective plots, and all samples were oven-dried at 70oc for 72 h, weighed, ground, and then subsamples were taken for n determination. the standard micro-kjeldahl procedure measured n content in the grains and straw (bremner and mulvaney, 1982). n uptake in grain and straw was calculated by following formulae. nitrogen uptake by grain (kg ha-1) = % n in grain × grain yield (kg ha-1 ) 100 nitrogen uptake by straw (kg ha-1) = % n in straw × straw yield (kg ha-1 ) 100 the optimum n dose for the tested aus rice variety was determined by regression of the grain yield with the n rates: y = a + bn+ cn2 where y is rice yield (kg ha−1), n is nitrogen dose (kg ha−1), a is intercept (estimated yield without n application), b and c are coefficients, respectively. differentiating y with respect to n of the equation gives the n dose for the maximum yield. the optimum n dose for maximum yield is calculated by n= -b/2c, and the equation of economic n rate is x= (en-b)/2c. where, en= pf/py. here, pf indicates the price of n fertilizer (18 tk kg−1 and py indicates the price of paddy (tk kg−1). the data obtained for different characters were statistically analyzed with the computerbased software cropstat v. 7.2, and mean separation was done by the least significance difference test (lsd) at a 5% level of significance. regression analyses were done to determine the economic n rates of the respective varieties. economic nitrogen rate for transplanted aus rice 87 results and discussion nitrogen concentration (n%) in plant parts during growth stage nitrogen is the only nutrient that has not a common soil mineral source. nitrogen in beneficial forms of plants is probably the most limited nutrient for plant growth. most of plants' nutritional dynamics and supply rates are related to model n. nitrogen concentration (n%) was significantly influenced by different varieties used in the present study (table 2). table 2. nitrogen concentration (%) of br26, brri dhan48, and brri dhan82 as affected by nitrogen rates at brri farm, gazipur br26 n0 0.25 0.47 0.52 0.57 0.29 0.20 n40 0.34 0.84 0.89 0.90 0.67 0.48 n60 0.45 1.01 1.14 1.07 0.79 0.69 n80 0.50 1.16 1.52 1.18 0.83 0.79 n100 0.52 1.54 1.74 1.31 0.87 0.82 brri dhan48 n0 0.23 0.53 0.55 0.46 0.22 0.21 n40 0.26 0.76 0.92 0.84 0.59 0.59 n60 0.39 1.02 1.15 1.05 0.83 0.70 n80 0.43 1.31 1.58 1.15 0.88 0.81 n100 0.45 1.54 1.70 1.39 0.91 0.87 brri dhan82 n0 0.21 0.53 0.53 0.49 0.21 0.23 n40 0.29 0.88 0.90 0.80 0.55 0.52 n60 0.34 1.18 1.22 1.01 0.75 0.69 n80 0.46 1.41 1.71 1.09 0.83 0.76 n100 0.52 1.65 1.74 1.25 0.91 0.82 lsd (0.05) ns ns ns ns ns ns cv (%) 18.6 12.4 9.5 7.7 10.1 10.2 note: ns= non-significant; n0= 0 (control), n1= 40 kg ha−1, n2 60 kg ha−1, n3= 80 kg ha−1, n4= 100 kg ha−1 at 15 dat (days after transplanting), in br26, the n concentration was recorded as 0.41. the results obtained from brri dhan48 showed the lowest n concentration (0.35). on 30 treatment days after transplanting 15 dat 30 dat 45 dat 60 dat 75 dat maturity variety br26 0.41 1.01 1.16 1.01 0.69 0.59 brri dhan48 0.35 1.03 1.18 0.98 0.69 0.63 brri dhan82 0.36 1.13 1.22 0.93 0.65 0.60 lsd (0.05) 0.52 0.98 ns 0.56 ns ns nitrogen rate n0 0.23 0.51 0.54 0.52 0.24 0.21 n1 0.29 0.83 0.90 0.85 0.60 0.53 n2 0.39 1.07 1.17 1.04 0.79 0.69 n3 0.47 1.29 1.60 1.14 0.84 0.78 n4 0.49 1.58 1.73 1.32 0.89 0.84 lsd (0.05) 0.68 0.13 0.11 0.72 0.66 0.60 cv (%) 18.6 12.4 9.5 7.7 10.1 10.2 variety × nitrogen rate 88 masum et al. dat, brri dhan82 (1.13) recorded the highest n percentage and the lowest (1.01) from br26. at 45 dat, the highest n concentration was recorded by brri dhan82 (1.22) and the lowest (1.16) from br26. at 60 dat, the highest n concentration (0.98) was obtained from brri dhan48 and the lowest (0.56) from brri dhan82. at 75 dat, the highest n concentration (0.69) was obtained from brri dhan48 and br26 and the lowest (0.65) from brri dhan82. at maturity, the highest n concentration (0.63) was obtained from brri dhan48 and the lowest (0.59) from br26. nitrogen concentration in plant parts increased over time due to the application of nitrogenous fertilizer and plant demand. thereafter it seems to decline trend towards maturity. similar research findings were also reported by zhang et al. (2009), haque et al. (2015a), and djaman et al. (2016). different levels of n application showed statistically significant variations in n concentration (n%) of aus rice at 15, 30, 45, 60, 75 dat, and maturity (table 2). at 15 dat, the highest n concentration (0.49) was recorded by n100 (100 kg ha−1), closely followed (0.47) by n80 (80 kg n ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest n concentration (0.23). on 30 dat, the highest n concentration (1.58) was recorded by n100 (0 kg ha−1) and the lowest (0.51) from n0 (0 kg ha−1). at 45 dat, the highest n concentration (1.73) was recorded by n100 (100 kg ha−1) and the lowest (0.54) from n0 (0 kg ha−1). at 60 dat, the highest n concentration (1.32) was obtained from n100 (100 kg ha−1) and the lowest (0.52) from n0 (0 kg ha−1). at 75 dat, the highest n concentration (0.89) was obtained from n100 (100 kg ha−1) and the lowest (0.24) from n0 (0 kg ha−1). at maturity, the highest n concentration (0.84) was obtained from n100 (100 kg ha−1) and the lowest (0.21) from n0 (0 kg ha−1). perez et al. (1996), cassman et al. (2003), and djaman et al. (2018) reported that improvement in crop yields is attributed to the increase in fertilizer use, especially n fertilizer. the combination effect of variety and different n rates application had an insignificant influence on n concentration at different growth stages of the three varieties of aus rice (table 2) however, at 45 dat, the highest n concentration (1.74) was observed from brri dhan82 and br26 × n100, (100 kg ha−1). at maturity, the lowest n concentration (0.20) was found from the combination of br26 x n0 (0 kg ha−1). similarly, many researchers recorded n concentrations for different rice varieties with n rates (peng et al., 2004; djaman et al., 2016; djaman et al., 2018). nitrogen uptake by plants during growth stage nitrogen uptake (nup) was significantly influenced by different varieties used in the present study (table 3) during 15, 30, and 60 dat. at 15 dat, the highest nup was recorded by br26 (3.85 kg ha−1). the results obtained from brri dhan48 showed the lowest nup (2.99 kg ha−1). on 30 dat, the highest nup was recorded by brri dhan82 (26.29 kg ha−1) and the lowest (23.18 kg ha−1) from br26. at 45 dat, the highest nup was recorded by brri dhan82 (53.67 kg ha−1) and the lowest (50.50 kg ha−1) from br26. at 60 dat, the highest nup (63.58 kg ha−1) was obtained from br26, and the lowest (56.26 kg ha−1) from brri dhan82. at 75 dat, the highest nup (56.33 kg ha-1) was obtained from br26 and the lowest (52.66 kg ha−1) from brri dhan82. at maturity, the highest nup (42.63 kg ha−1) was obtained from brri dhan48 and the lowest (42.05 kg ha−1) from br26. arthanari et al. (2007) reported that the response of rice to nutrient uptake may vary with varieties. similar research findings were also reported by koutroubas and ntanos (2003) and artacho et al. (2009). different n levels showed statistically significant variations in the nup of aus rice at 15, 30, 45, 60, 75 dat, and maturity (table 3). at 15 dat, the highest nup (4.69 kg ha−1) was recorded by n100 (100 kg ha−1), closely followed (4.59 kg ha−1) by n80 (80 kg n ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest nup (1.67 kg ha−1). on 30 dat, the highest nup (35.97 kg ha−1) was recorded by n100 (0 kg ha−1) and the lowest (10.11 kg ha−1) from n0 (0 kg ha−1). at 45 dat, the highest nup (75.14 kg ha−1) was recorded by n100 (100 kg ha−1) and the lowest (21.51 kg ha−1) from n0 (0 kg ha−1). at 60 dat, the highest nup (82.34 kg ha−1) was obtained from n100 (100 kg ha-1) and the economic nitrogen rate for transplanted aus rice 89 lowest (48.79 kg ha−1) from n0 (0 kg ha−1). at 75 dat, the highest nup (72.67 kg ha−1) was obtained from n100 (100 kg ha-1) and the lowest (17.85) from n0 (0 kg ha−1). table 3. nitrogen uptake (kg ha−1) of br26, brri dhan48, and brri dhan82 as affected by nitrogen rates at brri farm, gazipur treatment days after transplanting 15 dat 30 dat 45 dat 60 dat 75 dat maturity variety br26 3.85 23.18 50.50 63.58 56.33 42.05 brri dhan48 2.99 22.22 50.67 58.94 53.60 42.63 brri dhan82 3.22 26.29 53.46 56.26 52.66 42.36 lsd (0.05) 0.45 2.25 ns 3.63 ns ns nitrogen rate n0 1.67 10.11 21.51 27.79 17.85 11.95 n1 2.38 17.45 37.47 48.79 45.75 32.12 n2 3.49 24.49 50.50 64.32 63.93 49.22 n3 4.54 31.47 73.09 74.74 70.78 58.62 n4 4.69 35.97 75.14 82.34 72.67 59.82 lsd (0.05) 0.59 2.91 4.56 4.68 5.46 4.35 cv (%) 18.1 12.6 9.2 8.1 10.4 10.6 variety × nitrogen rate br26 n0 1.92 9.45 21.04 31.71 21.79 11.57 n40 2.82 17.72 36.89 52.71 51.19 30.32 n60 4.03 23.31 49.23 67.11 64.79 49.24 n80 5.02 29.73 69.81 82.70 71.95 59.19 n100 5.47 35.69 75.52 83.69 71.89 59.93 brri dhan48 n0 1.57 9.99 21.85 24.55 16.15 11.30 n40 1.99 15.73 38.11 47.49 44.54 33.95 n60 3.39 22.73 49.76 63.55 64.75 48.46 n80 4.09 28.66 70.86 74.70 71.58 59.17 n100 3.89 33.99 72.76 84.39 70.99 60.26 brri dhan82 n0 1.53 10.89 21.64 27.09 15.62 12.97 n40 2.30 18.91 37.42 46.18 41.51 32.09 n60 3.06 27.42 52.51 62.29 62.25 49.97 n80 4.51 36.04 78.59 66.80 68.79 57.49 n100 4.71 38.23 77.13 78.94 75.11 59.26 lsd (0.05) ns ns ns ns ns ns cv (%) 18.1 12.6 9.2 8.1 10.4 10.6 note: ns= non-significant; n0= 0 (control), n1= 40 kg ha−1, n2 60 kg ha−1, n3= 80 kg ha−1, n4= 100 kg ha−1 at maturity, the highest nup (59.82 kg ha-1) was obtained from n100 (100 kg ha−1) and the lowest (11.95 kg ha−1) from n0 (0 kg ha−1). present research results indicate that total n uptake by rice plants increased with increased n rates up to a certain level, then decreased. yesuf and balcha (2014) also reported similar findings. sharma and mittra (1990), paikaray et al. (2001), jahan et al. (2014), islam et al. (2015), and hussain et al. (2016) reported that the use of an optimum dose of n might have helped for good vegetative growth and root system, which increased the higher n uptake by plants and hence increased yield and yield components of rice. the combination effect of variety and different n rate applications had a non-significant influence https://www.tandfonline.com/doi/full/10.1080/24749508.2020.1742509 https://www.tandfonline.com/doi/full/10.1080/24749508.2020.1742509 90 masum et al. on nup at different growth stages of the three varieties of aus rice (table 3). therefore, at 60 dat, the highest nup (84.39 kg ha−1) was observed from brri dhan82 × n100 (100 kg ha−1), closely followed (83.69 kg ha−1) by n100 (100 kg n ha−1) from br26. at 15 dat, the lowest nup (1.52 kg ha−1) was found from the combination of brri dhan82 × n0 (0 kg ha−1) closely followed (1.57 kg ha−1) by n0 (0 kg n ha−1) from brri dhan48. similar research findings were also reported by paikaray et al. (2001) and jahan et al. (2014). nitrogen concentration (n%) in grains nitrogen concentration of grain yield was significantly influenced by different varieties used in the present study (table 4). the highest n concentration (n%) of grain yield was recorded by brri dhan48 (0.93). the results obtained from br26 showed the lowest n concentration (n%) of grain yield (0.82). different n levels showed statistically significant variations in n concentration (n%) of grain yield of aus rice (table 4). table 4. nitrogen concentration (n%) and nitrogen uptake (kg n ha−1) of br26, brri dhan48, and brri dhan82 as affected by nitrogen rates at brri farm, gazipur treatment n (%) in grain n (%) in straw n (%) in grain + straw n uptake grain (kg ha-1) n uptake in straw (kg ha-1) n uptake (grain+ straw) (kg ha-1) nitrogen harvest index (%) variety br26 0.82 0.41 1.22 31.93 19.91 51.84 60.41 brri dhan48 0.93 0.34 1.27 43.31 19.03 62.34 68.15 brri dhan82 0.89 0.33 1.21 35.04 16.38 51.42 66.68 lsd (0.05) 0.58 0.22 ns 5.13 2.43 7.11 2.36 nitrogen rate n0 0.52 0.26 0.78 14.96 10.13 25.09 59.43 n1 0.72 0.33 1.06 26.49 16.03 42.52 62.17 n2 0.99 0.37 1.36 45.37 20.47 65.83 68.52 n3 1.07 0.41 1.48 52.36 23.24 75.60 69.12 n4 1.08 0.43 1.51 44.61 22.35 66.95 66.15 lsd (0.05) 0.75 0.28 0.74 6.63 3.14 9.18 3.05 cv (%) 8.9 8.1 6.2 18.7 17.6 17.2 4.8 variety × nitrogen rate br26 n0 0.48 0.29 0.76 12.51 10.10 22.61 55.38 n40 0.68 0.38 1.06 22.24 16.82 39.06 57.20 n60 0.89 0.42 1.31 37.58 21.86 59.44 63.01 n80 1.01 0.48 1.49 45.27 26.01 71.28 63.70 n100 1.02 0.47 1.49 42.03 24.77 66.80 62.75 brri dhan48 n0 0.61 0.26 0.87 17.89 10.69 28.58 62.84 n40 0.79 0.34 1.13 29.29 16.23 45.52 64.19 n60 1.01 0.34 1.36 53.39 20.82 74.21 71.89 n80 1.10 0.37 1.47 61.48 23.46 84.94 72.37 n100 1.12 0.39 1.52 54.49 23.96 78.46 69.44 brri dhan82 n0 0.47 0.22 0.69 14.48 9.60 24.08 60.06 n40 0.70 0.28 0.98 27.94 15.04 42.98 65.12 n60 1.06 0.34 1.40 45.14 18.72 63.85 70.67 n80 1.12 0.37 1.48 50.34 20.25 70.59 71.29 n100 1.10 0.41 1.51 37.29 18.31 55.59 66.24 lsd (0.05) ns ns ns ns ns ns ns cv (%) 8.9 8.1 6.2 18.7 17.6 17.2 4.8 note: ns= non-significant; n0= 0 (control), n1= 40 kg ha−1, n2 60 kg ha−1, n3= 80 kg ha−1, n4= 100 kg ha−1 economic nitrogen rate for transplanted aus rice 91 the highest n concentration (n%) of grain yield (1.08) was recorded by n100 (100 kg ha−1), which was closely followed (1.07) by n80 (80 kg n ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest n concentration (n%) of grain yield (0.52). the combination effect of variety and different n rate application had no significant influence on the grain yield of the three aus rice varieties (table 4). the highest n concentration (n%) of grain yield (1.12) was observed from brri dhan48 × n100 (100 kg ha−1) and brri dhan82 × n80 (80 kg ha−1), and the lowest n concentration (n%) of grain yield (0.47) was found from the combination of brri dhan82 × n0 (0 kg ha−1). nitrogen uptake by grains nitrogen uptake of grain yield was significantly influenced by different varieties used in the present study (table 4). the highest nup of grain yield was recorded by brri dhan48 (43.31 kg n ha−1). the results obtained from br26 showed the lowest nup of grain yield (31.93 kg ha−1). different n levels showed statistically significant variations in nup of grain yield of aus rice (table 4). the highest nup of grain yield (52.36 kg ha−1) was recorded by n80 (80 kg ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest nup of grain yield (14.96 kg ha−1). the combination effect of variety and different n applications had no significant influence on the nup of grain yield of the three varieties of aus rice (table 4). the highest nup of grain yield (61.48 kg ha−1) was observed from brri dhan48 × n80 (80 kg ha−1), and the lowest nup of grain yield (12.51 kg ha−1) was found from the combination of br26 × n0 (0 kg ha−1). nitrogen concentration (n%) in straw the n concentration of straw was significantly influenced by the different varieties used in the present study (table 4). the highest n concentration of straw yield was recorded by br26 (0.41). the results obtained from brri dhan82 showed the lowest n concentration of straw (0.33). different n levels showed statistically significant variations in terms of n concentration of straw of aus rice (table 4). the highest n concentration of straw yield (0.43) was recorded by n100 (100 kg ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest n concentration of straw yield (0.26). the combination effect of variety and different n applications had no significant influence on the n concentration of straw of the three varieties of aus rice (table 4). the highest n concentration of straw (0.48) was observed from br26 × n80 (80 kg ha−1), and the lowest n concentration of straw yield (0.22) was found from the combination of brri dhan82 × n0 (0 kg ha−1). nitrogen uptake by straw nitrogen uptake of straw yield was significantly influenced by different varieties used in the present study (table 4). the highest nup of straw yield was recorded by br26 (19.91 kg ha−1). the results obtained from brri dhan82 showed the lowest nup of straw yield (16.38 kg ha−1). different n levels showed statistically significant variations in nup of the straw yield of aus rice at days after transplanting (table 4). the highest nup of straw yield (23.24 kg ha−1) was recorded by n80 (80 kg ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest nup of straw yield (10.23 kg ha−1). the combination effect of variety and different n applications had no significant influence on the nup of the straw yield of the three varieties of aus rice (table 4). the highest nup of straw yield (26.01 kg ha−1) was observed from br26 × n80 (80 kg ha−1), and the lowest nup of straw yield (9.60 kg ha−1) was found from the combination of brri dhan82 × n0 (0 kg ha−1). 92 masum et al. nitrogen harvest index n accumulation in grains (n accumulation in grains plus dry matter/ straw) explain the n harvest index. the n harvest index was significantly influenced by different varieties used in the present study (table 4). the highest n harvest index was recorded by brri dhan48 (68.15%). the results obtained from br26 showed the lowest n harvest index (60.41%). different n levels showed statistically significant variations in terms of the n harvest index of aus rice (table 4). the highest n harvest index (69.12) was recorded by n80 (80 kg ha−1). the results obtained from n0 (0 kg ha−1) showed the lowest n harvest index (59.43). the combination effect of variety and different n rates had no significant influence on the n harvest index of the three varieties of aus rice (table 4). the highest n harvest index (72.37%) was observed from brri dhan48 × n80 (80 kg ha−1), and the lowest n harvest index (55.38%) was found from the combination of br26 × n0 (0 kg ha−1). relationship between grain yield and grain n uptake and grain yield with total n uptake grain yield of varieties and n uptake in grain and total n uptake were significantly and linearly related (r2 = 0.8863** and 0.8619**) (figure 1 “a, b”), indicating that higher grain yield would be due to higher n uptake. nitrogen use efficiency is largely influenced by grain yield, n fertilizer input, and n uptake (qiao et al., 2012). fig. 1. relationship between grain yield and grain n uptake and grain yield with total n uptake (**= significant at 1% level). determination of optimum and economic of n doses the variation of grain yield of br26, brri dhan48, and brri dhan82 at different n rates was determined through regression equation (figure 2). differentiating the quadratic equation of yield response concerning applied different n doses, the optimum n rate appeared as 99, 95 and 57 kg ha−1 for br26, brri dhan48, and brri dhan82, respectively. considering economic n rate would be 97, 93, and 53 kg ha−1 for br26, brri dhan48, and brri dhan82, respectively. fageria and santos (2014) also found efficient and moderately efficient rice varieties in n use efficiency, and none were grouped as inefficient. a b economic nitrogen rate for transplanted aus rice 93 fig. 2. grain yield responses to n fertilization and determination of optimum and economic n doses in different aus varieties during aus 2019 at brri, gazipur (*=significant at 5% level) conclusion the economic n rates calculated from the quadratic regression equations were 97 kg ha−1, 95 kg ha−1, and 55 kg ha−1 for br26, brri dhan48, and brri dhan82, respectively. therefore, the n fertilizer requirement of aus rice crops should be based on variety, and the inherent capacity of soil n supply to improve aus rice yield furthermore minimize the excessive use of chemical 94 masum et al. fertilizer. after all, to reach a specific conclusion and recommendation, more research works on varieties and n rates for better growth and yield of aus rice should be done over different agroecological zones of bangladesh to make a promising practice to the farmers. references artacho, p., c. bonomelli and f. meza. 2009. nitrogen application in irrigated rice grown in mediterranean conditions: effects on grain yield, dry matter production, nitrogen uptake, and nitrogen use efficiency. j. plant nutr. 32: 1574-1593. arthanari, p.m., s. ramasamy and m.m. amanullah. 2007. nutrient uptake as influenced by post panicle initiation nutrient management in rice plant organ. res. j. agric. biol. sci. 3: 621-624. bbs. 2021. national accounts statistics. bangladesh bureau of statistics, government of the people’s republic of bangladesh. bremner, j.m. and c.s. mulvaney. 1982. total nitrogen. in: methods of soil analysis: part 2 chemical and microbiological properties, a.l. page, r.h. miller and d.r. keeney (eds.). american society of agronomy, soil science society of america, madison, wisconsin. pp. 595-624. brri. 2021. adhunik dhaner chash (cultivation of modern rice). bangladesh rice research institute, gazipur, bangladesh. pp. 5-93. cassman, k.g., a. dobermann, d.t. walters and h. yang. 2003. meeting cereal demand while protecting natural resources and improving environmental quality. annu. rev. environ. resour. 28: 315-358. chamely, s., n. islam, s. hoshain, m. rabbani, m. kader and m. salam. 2015. effect of variety and nitrogen rate on the yield performance of boro rice. progressive agric. sci. 26(1): 6-14. djaman, k., b.v. bado and v.c. mel. 2016. effect of nitrogen fertilizer on yield and nitrogen use efficiency of four aromatic rice varieties. emir. j. food agric. 28: 126-135. djaman, k., v.c. mel, f.y. ametonou, r.e. namakyand and m.d. diallo. 2018. effect of nitrogen fertilizer dose and application timing on yield and nitrogen use efficiency of irrigated hybrid rice under semiarid conditions. j. agric. sci. food res. 9: 223. fageria, n.k. 2009. the use of nutrients in crop plants. crc press, boca raton, fl. pp. 20-50. fageria, n.k. and a.b. santos. 2014. lowland rice genotypes evaluation for nitrogen use. j. plan. nutr. 37(9): 1410-1423. fan, m., j. shen, l. yuan, r. jiang and x. chen. 2012. improving crop productivity and resource use efficiency to ensure food security and environmental quality in china. j. exp. bot. 63: 13-24. haider, i.k. 2018. appraisal of biofertilizers in rice: to supplement inorganic chemical fertilizer. rice sci. 25: 357-362. haque, m.a., a.h.m. razzaque, a.n.a. haque and m.a. ullah. 2015. effect of plant spacing and nitrogen on yield of transplant aman rice var. brri dhan52. j. biosci. agric. res. 4(2): 52-59. hasegawa, t., y. koroda and n.g. eligman. 1994. response to spikelet number of plant nitrogen concentration and dry weight in paddy. agron. j. 86: 673-676. hassan, m.s., a. khair, m.m. haque, a.k. azad and a. hamid. 2009. genotypic variation in traditional rice varieties for chlorophyll content, spad value and nitrogen use efficiency. bangladesh j. agric. res. 34(3): 505-515. hussain, j., m.a. siddique, m.m. mia, g.n. hasan, a.s. seajuti, m.r. mallik and e. zaman. 2016. effect of different doses of nitrogen fertilizer on t. aman rice. int. j. bus. soc. sci. res. 4(4): 328-332. islam, m.s.m., y.k. gaihre, a.l. shah, u. singh, m.i.u. sarkar, m.a. satter, j. sanabria and j.c. biswas. 2016. rice yields and nitrogen use efficiency with different fertilizers and water management under intensive lowland rice cropping systems in bangladesh. nutr. cycl. agroecosystems. 106: 143-156. islam, s.m.m., a. khatun, f. rahman, a.t.m.s. hossain, u.a. naher and m.a. saleque. 2015. rice response to nitrogen in tidal flooded non-saline soil. bangladesh rice j. 19(2): 65-70. jahan, n., m.r. islam, a.b. siddique, m.r. islam, m.m. hassan, s.m. shamsuzzaman and a.w. samsuri. 2014. effects of integrated use of prilled urea, urea super granule and poultry manure on yield of transplant aus rice and field water quality. j. life sci. 11: 101-108. koutroubas, s.d. and d.a. ntanos. 2003. genotypic differences for grain yield and nitrogen utilization in indica and japonica rice under mediterranean conditions. field crops res. 83: 251-260. economic nitrogen rate for transplanted aus rice 95 liu, x., h. wang, j. zhou, f. hu, d. zhu, z. chen and y. liu. 2016. effect of n fertilization pattern on rice yield, n use efficiency and fertilizer-n fate in the yangtze river basin, china. plos one, 11(11): e0166002. masum, s.m., m.h. ali and m.j. ullah. 2008. growth and yield of two t. aman rice varieties as affected by seedling number per hill and urea supper granules. j. agric. educ. technol. 11(1 & 2): 51-58. meena, s.l., s. surendra, y.s. shivay and s. singh. 2003. response of hybrid rice (oryza sativa) to nitrogen and potassium application in sandy clay loam soils. indian j. agric. sci. 73(1): 8-11. nasim, m., s.m., shahidullah, a. saha, m.a. muttaleb, t.l. aditya, m.a. ali and m.s. kabir. 2017. distribution of crops and cropping patterns in bangladesh. bangladesh rice j. 21(2): 1-55. paikaray, r.l., b.s.l. mahapatra and g.l sharma. 2001. integrated nitrogen management in rice (oryza sativa), wheat (tricum aestivum) cropping system. indian j. agron. 46(4): 592-600. peng, s., j. huang, j.e. sheehy, r.c. laza and r.m. visperas. 2004. rice yields decline with higher night temperature from global warming. proc. natl. acad. sci. u.s.a. 101: 9971-9975. perez, c.m., b.o. juliano, s.p. liboon, j.m. alcantara and k.g. cassman. 1996. effects of late nitrogen fertilizer application on head rice yield, protein content, and grain quality of rice. cereal chem. 73: 556-560. qiao, j., l. yang, t. yan, f. xue and d. zhao. 2012. nitrogen fertilizer reduction in rice production for two consecutive years in the taihu lake area. agric. ecosyst. environ. 146(1): 103-112. sharma, a.r. and b.n. mittra. 1990. effect of n and p on rice and their residual effect on succeeding wheat/gram crop. indian j. agron. 34: 40-44. talashilker, s.c. and o.p. vimol. 1986. studies on increasing the use efficiency of n and p fertilizers in combination with city solid waste. j. indian soc. soil sci. 34(4): 780-784. tayefe, m., a. gerayzade, e. amiri and a.n. zade. 2014. effect of nitrogen on rice yield, yield components and quality parameters. afr. j. biotechnol. 13(1): 91-105. usda. 2020. usda, world agricultural outlook board, world agricultural supply and demand estimates, washington, dc 20250, united states. yesuf, e. and a. balcha. 2014. effect of nitrogen application on grain yield and nitrogen efficiency of rice (oryza sativa l.). asian j. crop sci. 6(3): 273-280. zhang, h., y. xue, z. wang, j. yang and j. zhang. 2009. alternate wetting and moderate soil drying improves root and shoot growth in rice. crop sci. 49: 2246-2260. bangladesh agron. j. 2023, 26(1): 75-83 enhancing salt stress tolerance and yield parameters of proso millet through exogenous proline and glycine betaine supplementation m.m. alam and m. hasanuzzaman* department of agronomy, faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh. *corresponding author, email: mhzsauag@yahoo.com (received: 13 july 2023, accepted: 01 september 2023) keywords: proso millet, abiotic stresses, salinity, relative water content, ionic toxicity abstract proline (pro) and glycine betaine (gb) act as significant osmoprotectants, potentially mitigating the detrimental effects of various abiotic stresses in plants. given the growth-enhancing capabilities and other regulatory roles of pro and gb, the current study was conducted to assess their function in imparting salt stress resilience in proso millet (panicum miliaceum l). proso millet plants were subjected to two levels of salt stress (s1 = 150 mm; s2 = 300 mm). foliar applications of pro (0.5 mm) and gb (0.5 mm) were provided under control and salt-stressed conditions at 10-day intervals twice. compared to control conditions, plant growth, fresh and dry weight, leaf relative water content (rwc), spad value, and yield-contributing attributes noticeably decreased under salt stress. in contrast, plants supplemented with pro and gb exhibited enhanced characteristics. moreover, growth and yield parameters improved in salttreated proso millet plants when supplemented with pro and gb. these results suggest that the foliar application of pro and gb can alleviate salt-induced oxidative stress in proso millet plants by modulating the antioxidative defense. introduction agricultural productivity across the globe is critically endangered by an array of abiotic stresses, such as drought, salinity, flooding, and extreme temperatures. salinity, prevalent in over 100 countries, is particularly concerning as it degrades agricultural quality and yield, posing a significant environmental challenge (dey et al., 2021; sabagh et al., 2021). studies reveal that nearly 20% of the earth's arable land grapples with the harmful impacts of salt stress (hasanuzzaman and fujita, 2022). this stress leads to excessive absorption of sodium (na+) and chloride (cl−) ions, triggering ionic stress and cytotoxicity that severely hamper plant growth and development (shah et al., 2021). among the affected crops, proso millet (panicum miliaceum l.), a drought-resistant variety, is significantly vulnerable to salinity stress. despite its drought resistance, it demonstrates limited tolerance to elevated salt levels (zou et al., 2019). high soil salinity upsets the plant's water balance, creating a water deficit and inhibiting nutrient uptake. the resulting osmotic stress from salt accumulation hinders growth, diminishes photosynthetic activity, and disrupts reproductive development (akhter et al., 2021; shah et al., 2021; mushtaq et al., 2023). the escalation of oxidative damage due to reactive oxygen species (ros) accumulation also results in cell membrane and cellular dysfunction (hasanuzzaman et al., 2020; saleem et al., 2021; hasanuzzaman and fujita, 2022). managing salinity stress requires an integrated approach, incorporating agronomic practices, breeding initiatives, and innovative biotechnological tools. the development of saltresistant varieties, refining irrigation techniques, and deploying effective soil management about:blank 76 alam & hasanuzzaman strategies are all steps towards mitigating the adverse effects of salinity stress. additionally, researchers were exploring various biochemical strategies to amplify the salinity tolerance of proso millet, including the external application of compounds such as proline (pro) and glycine betaine (gb). pro, an osmolyte integral to osmotic adjustment and stress resistance in plants, and gb, a crucial chemical osmoregulator, have both shown potential in alleviating salinity stress. they contribute to maintaining cellular osmotic balance, protect cells from oxidative damage, regulate stress response enzymes, and enhance the overall salt tolerance of proso millet (shafi et al., 2019; hosseinifard et al., 2022; zhu et al., 2022; bai et al., 2022). however, the efficiency of pro and gb is contingent on a myriad of factors such as concentration, method of application, and specific proso millet genotypes. with this in mind, this study was undertaken to evaluate the effects of applying pro and gb under varying salinity stress levels in proso millet cultivation. materials and methods plant materials and experimental design healthy proso millet (panicum miliaceum l.var. bari cheena-1) seeds were carefully chosen and consistently sown in 16 l plastic containers. baseline applications of organic manure and chemical fertilizers, including urea, triple superphosphate, and muriate of potash, were used. twenty days after sowing (das), along with the control group (0 mm nacl), we introduced mild (150 mm nacl) and severe salinity (300 mm nacl) to the plants. supplements of proline (pro) (50 μm) and glycine betaine (gb) (50 mm) were given at 10 and 20 das under both normal and saline conditions. the study employed a completely randomized design (crd) with three repetitions. evaluation of plant height proso millet plant heights were measured at 20, 30 das, and upon harvesting. a standard measuring scale was used to gauge the distance from the base level to the uppermost leaf tip of each plant. the average measurements were taken from five arbitrarily chosen plants from each pot. to calculate the fresh weight (fw) per plant, randomly uprooted three sample plants from each repetition and used a balance for weighing. after determining fw, the samples were dried in an oven at 80℃ for 48 h. following this, they were weighed again to measure the dry weight (dw), with the average dry weight recorded as dw per plant. assessment of spad values the spad meter (minolta camera co., osaka, japan) was utilized to evaluate the top, middle, and base sections of five randomly selected leaves from each pot. measurements from each section were then averaged (yuan et al., 2016). estimation of yield contributing parameters standard procedures were employed to measure parameters contributing to yield, including the number of tillers per hill, panicle length, filled and unfilled grains per panicle, 1000seed weight, and grain yield. measurement of relative water content five leaves were randomly chosen from each pot, cleaned, and weighed to determine the fresh weight (fw). the samples were then soaked in distilled water for 24 h, after which excess surface water was removed to measure the turgid weight (tw). the samples were then oven-dried enhancing salt stress tolerance of proso millet by proline and glycinebetaine 77 for 72 h to obtain the dry weight (dw). the relative water content (rwc) was calculated using the formula: rwc (%) = (fw−dw)/(tw−dw) × 100 (barrs and weatherley, 1962). statistical analysis the collected data from the three repetitions were statistically evaluated using staistix 10 software. a one-way analysis of variance (anova) was performed. fisher's least significant difference (lsd) test was applied at the 5% significance level to compare the mean differences. results and discussion when subjected to s1 and s2, a reduction of 5% and 18% in plant height was observed at 30 das, respectively. this reduction progressively intensified over time, with the most significant decrease recorded during harvest—13% and 27% for s1 and s2, respectively. nonetheless, the application of pro and gb counteracted the adverse effects of salt stress on plant height. while the impact wasn't considerable at 30 das under both s1 and s2, these compounds proved more effective at 50 das. pro, in particular, was highly successful in counterbalancing the detrimental effects of both levels of salt stress on proso millet. table 1. plant height at 30 das, 50 das, and at harvest of proso millet under salt stress supplemented by pro and gb treatment plant height (cm) 30 das 50 das at harvest c 18.77±0.62 ab 50.72±0.97 a 74.60±1.39 a pro 19.26±0.58 a 50.86±2.39 a 74.48±0.69 a gb 18.46±1.05 ab 51.36±0.99 a 75.22±0.72 a s1 14.71±0.52 ab 44.71±0.05 d 65.12±3.87 de s1+pro 16.33±0.32 bc 49.22±2.34 b 71.02±1.52 bc s1+gb 15.63±0.86 bc 47.56±1.58 c 68.38±3.01 cd s2 11.82±0.24 e 39.08±0.58 e 54.55±4.91 f s2+pro 14.25±0.51 cd 46.44±0.61 c 66.21±1.00 de s2+gb 13.26±0.74 d 44.93±2.19 d 63.28±4.59 e plant morphological attributes, such as plant height, were significantly affected by salt stress. this is due to a decrease in cell growth, chlorophyll content, nutrient absorption, relative water content, transpiration rate, and stomatal conductance (khalid et al., 2022; rasool et al., 2023). however, the accumulation of pro and gb can play a pivotal role in maintaining cellular osmotic balance, scavenging reactive oxygen species, and stabilizing proteins and membranes. consequently, these osmo-protectants effectively counteract the adverse effects of salinity stress on plant growth, allowing plants to flourish even under demanding conditions (desok et al., 2019; dikilitas et al., 2020; khalid et al., 2022). for instance, de freitas et al. (2019) reported increased plant growth, gas exchange, and relative water content when sorghum bicolor plants were sprayed with 30 mm of pro under 75 mm of nacl stress. similarly, enhanced plant height and chlorophyll content were observed in oryza sativa when treated with gb spray under salt stress (annunziata et al., 2019). moreover, abbas et al. (2012) found that salt-stressed citrus sinensis plants, sprayed with pro (25 mg l−1), 78 alam & hasanuzzaman showed an increased production rate of salt-responsive proteins and a decreased salt impact on plant height and leaf numbers, aligning with our current findings. under salt stress conditions, both fresh weight (fw) and dry weight (dw) decrease in a dose-dependent manner. when exposed to s1 and s2, fw reduced by 18% and 27%, respectively. however, the application of sa proved to be more effective under both s1 and s2, enhancing fw by 13% and 12%, respectively. a similar trend was observed for dw. the most significant decrease (34%) in dw occurred under s2, but sa and pro were able to enhance it by 12% and 17%, respectively, under s1. meanwhile, under s2, these agents could only increase dw by 17% and 12%, respectively. fig. 1. fresh weight (a) and dry weight (b) of proso millet under salt stress supplemented by salicylic acid and pro.here, pro and gb represent pro and gb, respectively. elevated salinity levels can significantly negatively impact plants, leading to noticeable effects such as plant mortality and reduced productivity (hannachi et al., 2022). increased soil salinity can trigger osmotic stress, resulting in a prolonged water deficit within plant cells. at the same time, it can induce severe ion toxicity and oxidative damage, collectively inflicting detrimental effects on plant growth, which consequently reduces both the fresh weight (fw) and dry weight (dw) of the plants (desok et al., 2019; qaoud et al., 2023). as illustrated in (figure 1), nacl stress has noticeably reduced the assessed parameters in proso millet. this reduction could likely be due to two reasons. first, the presence of salt in the soil solution hinders water uptake from the plant root zone to the cell, leading to a decreased growth rate. second, excessive salt infiltration through the transpiration streams can cause cellular injuries to the transpiring leaves. these injuries could potentially lead to further damage, resulting in diminished photosynthetic and growth capacities (elhindi et al., 2017; shehata and nosir, 2019). however, pro plays a pivotal role in maintaining ion homeostasis within plants. it helps mitigate the uptake of toxic ions such as sodium and facilitate the uptake of essential nutrients like potassium. this ion balance supports critical metabolic processes, bolsters energy production, and aids nutrient transport. as a result, it fosters increased biomass accumulation, leading to a higher fw and dw in plants (ibrahim et al., 2019). conversely, gb, a naturally occurring compound, has been found to significantly enhance plant growth and promote dry weight accumulation under salt stress conditions (joushan et al., 2020). enhancing salt stress tolerance of proso millet by proline and glycinebetaine 79 fig. 2. spad value (a) and rwc (b) of proso millet under salt stress supplemented by salicylic acid and pro. here, pro and gb represent pro and gb, respectively. at 30 das, the spad value decreased by 11% and 17% under s1 and s2 conditions, respectively, compared to the control plants. however, the application of pro and gb to stressed plants demonstrated a similar trend in mitigating salt stress-induced damage in proso millet. proso millet was affected more severely by a higher salt stress dose, s2 (18%), than the lower dose, s1 (9%), in terms of rwc. however, the application of pro and gb helped alleviate these negative effects. pro was found to be more effective under lower levels of salt stress compared to the higher one. under stress conditions, plants adopt an essential survival strategy by adjusting their photosynthetic capacity. this involves altering various photosynthetic attributes, including the spad value, to ensure their survival and optimal functioning despite adverse conditions. our findings conclusively demonstrate that applying exogenous pro and gb to leaves effectively counteracts the salt-induced decrease in spad value. this outcome is due to the osmoprotectant properties of pro and gb, which act as antitranspirants, allowing the plant to access more water over a prolonged period. consequently, photosynthesis is facilitated, contributing to the observed reduction in stress-related effects on the spad value (dawood et al., 2021). relative water content (rwc) serves as a reliable indicator of plant stress tolerance, offering valuable insights into their resilience and adaptability to challenging conditions. salinity stress induces osmotic stress, which has been shown to impact plants' rwc (mushtaq et al., 2023). accumulation of phytotoxic ions such as na+ and cl− in leaves disrupts nutrient balance, significantly reducing the concentrations of essential elements like k+ and ca2+. this disruption in ion equilibrium negatively affects plant water relations, leading to decreased rwc and leaf water potential (acosta-motos et al., 2017). in this study observed that increased salt concentrations resulted in a decrease in rwc. however, foliar application of pro and gb reinstated rwc, corroborating earlier findings by tang et al. (2015). salt stress significantly affected the yield-contributing characteristics (e.g., tiller number hill−1) of proso millet. the most significant reduction (41%) occurred under s2 compared to s1, measured at 30, 50 das, and during harvest. however, pro proved more effective than gb in counteracting the negative effects of salt stress on tiller number hill⁻1 under both salt stress doses from 30 das to harvest. salinity severely affects plants by impairing their reproductive capacity through hindrances in photosynthesis and assimilate production, leading to diminished yield and overall productivity (arif et al., 2020; shah et al., 2021). in reaction to increased soil salinity, plants initiate expedited water loss from their cells. for proso millet, water is critical for flowering and panicle formation, especially during the reproductive stage. therefore, water scarcity significantly impacts the plant's reproductive processes (yuan et al., 2022). 80 alam & hasanuzzaman the current study's results demonstrated that salt stress decreased panicle length, filled grain numbers, and 1000-grain weight, correlating with the reduction of proso millet's grain yield. under salt stress conditions, pro proved more effective than gb in mitigating negative effects on yield-contributing parameters like tiller number hill−1. exposure to s1 and s2 resulted in a decrease in panicle length by 22% and 47%, respectively, compared to the control. however, both pro and gb performed better under s2 than s1, increasing the panicle length by 17 and 11%, respectively (table 2). table 2. the number of tillers hill−1 at 30 das, 50 das, harvest and panicle length of proso millet under salt stress supplemented by pro and gb. treatment number of tiller hill−1 panicle length (cm) 30 das 50 das harvest c 1.444±0.040 a 3.989±0.016 a 3.6696±0.1372 a 18.8±0.62 ab pro 1.455±0.093 a 3.874±0.147 ab 3.6482±0.1401 a 19.3±0.58 a gb 1.479±0.041 a 3.737±0.074 b 3.6397±0.0452 a 18.5±1.05 b s1 1.094±0.030 c 2.964±0.045 e 2.9582±0.0453 c 14.7±0.52 d s1 + pro 1.234±0.068 b 3.517±0.130 c 3.3957±0.0596 b 16.3±0.32 c s1 + gb 1.220±0.033 b 3.345±0.126 cd 3.0477±0.1162 c 15.6±0.86 c s2 0.851±0.047 e 2.519±0.064 f 2.1923±0.1233 e 11.8±0.24 f s2 + pro 0.971±0.039 d 3.183±0.130 d 2.6402±0.0991 d 14.2±0.51 d s2 + gb 0.943±0.047 d 2.821±0.109 e 2.6010±0.0950 d 13.3±0.74 e the application of various salt levels had a negative impact on other yield-contributing parameters, such as filled grain panicle−1, unfilled grain panicle−1, 1000-grain weight, and the total yield of proso millet. exposure to s2 led to a 40% decrease in filled grain panicle−1 compared to the control. nevertheless, both pro and gb were more effective under s1 than s2, increasing the number of filled grain panicle−1by 15and 12%, respectively (figure 3a). similarly, there was a significant increase in unfilled grain panicle−1 by 28% under s2 compared to the control. however, the application of supplemental sa and pro increased the number of unfilled grain panicle−1 under both s1 and s2, with pro proving more effective than gb (figure 3b). fig. 3. the number of filled (a) and unfilled (b) grains panicle−1 of proso millet under salt stress supplemented by salicylic acid and pro. here, pro and gb represent pro and gb, respectively a significant decrease in 1000-grain weight was observed under s2, with a reduction of 39%, while it was only 23% under s1 compared to the control. pro demonstrated better efficacy than gb, resulting in a 21% increase in 1000-grain weight under s2 (figure 4a). under salt stress conditions, grain yield hill−1 was diminished by 19% and 41% under s1 and s2, respectively, enhancing salt stress tolerance of proso millet by proline and glycinebetaine 81 compared to the control. however, the supplementation of pro enhanced the grain yield hill−1 by 19% at s2 compared to s1 (figure 4b). fig. 4. the 1000-grain weight (a) and grain yield (b) of proso millet under salt stress supplemented by salicylic acid and pro. here, pro and gb represent pro and gb, respectively. the results of this experiment underscored the vital role of externally applied pro and gb in maintaining optimal physiological processes under salt stress. as osmo-protectants, pro and gb have the potential to reduce excessive water loss from cells, enabling plants to cope with water stress during periods of salt-induced osmotic imbalance. by promoting photosynthesis, they contribute to increased carbohydrate production, which is crucial for improving yield-contributing characteristics such as biomass accumulation and grain filling. moreover, by mitigating the adverse effects of salinity, these compounds enhance yieldcontributing parameters, including biomass production, grain filling, and overall crop productivity. thus, they play indispensable roles in improving crop performance in saline environments (tabssum et al., 2018; shemi et al., 2021). these findings underscore the valuable benefits of pro and gb in supporting plant growth and productivity in challenging environments. conclusion the results of this study provide compelling evidence that the individual and combined supplementation of pro and gb successfully mitigated the adverse effects of salt stress on proso millet. these treatments demonstrated a significant enhancement in the salt tolerance of proso millet. under salt stress conditions, the exogenous application of pro and gb resulted in notable improvements in both morphological and yield parameters of proso millet. moreover, the application of pro exhibited superior efficacy compared to gb in conferring resistance to different levels of salt stress. these findings highlight the potential of pro and gb as valuable tools for enhancing salt stress tolerance in proso millet and potentially other crops. further research and field trials will be required to explore their application in agricultural practices and their long-term effects on crop productivity. acknowledgements we would like to express our appreciation to the ministry of science and technology, government of the people's republic of bangladesh, for their valuable financial support in enabling the execution of this research work. the authors extend their sincere gratitude and 82 alam & hasanuzzaman appreciation to abdul awal chowdhury masud, assistant professor in the department of agronomy at sau, for his assistance in updating the manuscript. references abbas, m.f., a.m. jasim and h.a. al-taha. 2012. effect of exogenous proline on protein pattern changes in citrus sinensis (l.) osbeck under in vitro salt stress. adv. agric. bot. 4: 36-41. acosta-motos, j.r., m.f. ortuño, a. bernal-vicente, p. diaz-vivancos, m.j. sanchez-blanco and j.a. hernandez. 2017. plant responses to salt stress: adaptive mechanisms. agronomy 7: 18. akhter, m.s., s. noreen, s. mahmood, m. ashraf, a.a. alsahli and p. ahmad. 2021. influence of salinity stress on psii in barley (hordeum vulgare l.) genotypes, probed by chlorophyll-a fluorescence. j. king saud univ. sci. 33: 101239. annunziata, m.g., l.f. ciarmiello, p. woodrow, e. dell’aversana and p. carillo. 2019. spatial and temporal profile of glycine betaine accumulation in plants under abiotic stresses. front. plant sci. 10: 230. arif, y., p. singh, h. siddiqui, a. bajguz and s. hayat. 2020. salinity induced physiological and biochemical changes in plants: an omic approach towards salt stress tolerance. plant physiol. biochem. 156, 64– 77. bai, m., w. zeng, f. chen, x. ji, z. zhuang and jin, b. 2022. transcriptome expression profiles reveal response mechanisms to drought and drought-stress mitigation mechanisms by exogenous glycine betaine in maize. biotechnol. lett. 44: 367–386. barrs, h.d. and p.e. weatherley. 1962. a re-examination of the relative turgidity technique for estimating water deficits in leaves. aust. j. biol. sci. 15: 413–428. dawood, m.g., m.a. khater and m.e. el-awadi. 2021. physiological role of osmoregulators proline and glycinebetaine in increasing salinity tolerance of chickpea. egyptian j. chem. 64: 7637-48. de freitas, p.a., h.h. de carvalho, j.h. costa, r.d. miranda, k.d. saraiva, f.d. de oliveira, d.g. coelho, j.t. prisco, and e. gomes-filho. 2019. salt acclimation in sorghum plants by exogenous proline: physiological and biochemical changes and regulation of proline metabolism. plant cell rep. 8: 40316. desok, e.m., s.a. ibrahim and a.m. merwad. 2019. mitigation of salinity stress effects on growth, physiochemical parameters and yield of snapbean (phaseolus vulgaris l.) by exogenous application of glycine betaine. int. lett. nat. sci. 76: 60-71. dey, g., p. banerjee, p.k. sharma, j.p. maity, h. etesami and a.k. shaw. 2021. management of phosphorus in salinity-stressed agriculture for sustainable crop production by salt-tolerant phosphate solubilizing bacteria—a review. agronomy 11: 1552. dikilitas, m., e. simsek. and a. roychoudhury. 2020. role of proline and glycine betaine in overcoming abiotic stresses. in: amelioration of plant abiotic stress: biochemical and molecular perspectives, a. roychoudhury and d.k. tripathi (eds.). protective chemical agents in the. john wiley & sons ltd., new york. pp:1-23. elhindi, k.m., a.s. el-din and a.m. elgorban. 2017. the impact of arbuscular mycorrhizal fungi in mitigating salt-induced adverse effects in sweet basil (ocimum basilicum l.). saudi j. biol. sci. 24: 170-9. hannachi, s., k. steppe, m. eloudi, l. mechi, i. bahrini and m.c. van labeke. 2022. salt stress induced changes in photosynthesis and metabolic profiles of one tolerant (‘bonica’) and one sensitive (‘black beauty’) eggplant cultivars (solanum melongena l.). plants 11: 590. hasanuzzaman, m. and m. fujita. 2022. plant responses and tolerance to salt stress: physiological and molecular interventions. int. j. mol. sci. 9: 4810. hasanuzzaman, m., m.h.mb. bhuyan, f. zulfiqar, a. raza, s.m. mohsin, j.a. mahmud, m. fujita and v. fotopoulos. 2020. reactive oxygen species and antioxidant defense in plants under abiotic stress: revisiting the crucial role of a universal defense regulator. antioxidants 9: 681. hosseinifard, m., s. stefaniak., j.m. ghorban, e. soltani, l. wojtyla and m. garnczarska. 2022. contribution of exogenous proline to abiotic stresses tolerance in plants: a review. int. j. mol. sci. 23: 5186. ibrahim, a., a. awad, a. gendy and m. abdelkader. 2019. effect of proline foliar spray on growth and productivity of sweet basil (ocimum basilicum l.) plant under salinity stress conditions. zagazig j. agric. res. 46: 1877-1889. enhancing salt stress tolerance of proso millet by proline and glycinebetaine 83 joushan, z., h. sodeizadeh, m.a.h. ardakani, r. yazdani biouki and s. kajahhosseini. 2020. investigating the effect of foliar application of glycine betaine on some quantitative and qualitative characteristics of mint (mentha spicata l). under salinity stress. plant prod. 43: 267-280. khalid, m., h.m. rehman, n. ahmed, s. nawaz, f. saleem, s. ahmad, m. uzair, i.a. rana, r.m. atif, q.u. zaman and h.m. lam. 2022. using exogenous melatonin, glutathione, proline, and glycine betaine treatments to combat abiotic stresses in crops. int. j. mol. sci. 23: 12913. mushtaq, n. u., k. m. alghamdi, s. saleem, i. tahir, a. bahieldin, b. henrissat, m.k. alghamdi, r.u. rehman, and k. r. hakeem. 2023. exogenous zinc mitigates salinity stress by stimulating proline metabolism in proso millet (panicum miliaceum l.). front. plant sci. 14: 1053869. qaoud, h.a., h.a. ali, h. al-fares, t. qubbaj and m.j.y. shtaya. 2023. effect of salinity on the growth and some morphological traits of pearl millet. pak. j. bot. 55: 807-811. rasool, a., w. hafiz shah, s.a. padder, i. tahir, h.f. alharby, k.r. hakeem and r. rehman. 2023. exogenous selenium treatment alleviates salinity stress in proso millet (panicum miliaceum l.) by enhancing the antioxidant defence system and regulation of ionic channels. plant growth regul. 100: 479–494. sabagh, e.l., m.s. islam, m. skalicky, m.a. raza, k. singh and m.a. hossain, m., et al. 2021. salinity stress in wheat (triticum aestivum l.) in the changing climate: adaptation and management strategies. front. agron. 3: 661932. saleem, s., n.u. mushtaq, w.h. shah, a. rasool, k.r. hakeem and r.u. rehman. 2021. morphophysiological, biochemical and molecular adaptation of millets to abiotic stresses: a review. phyton. 90: 1363-1385. shafi, a., i. zahoor and u. mushtaq. 2019. proline accumulation and oxidative stress: diverse roles and mechanism of tolerance and adaptation under salinity stress. in: salt stress, microbes, and plant interactions: mechanisms and molecular approaches, m. akhtar (eds.). springer, singapore. pp. 269-300. shah, w.h., a. rasool, s. saleem, n.u. mushtaq, i. tahir and k.r. hakeem, et al. 2021. understanding the integrated pathways and mechanisms of transporters, protein kinases, and transcription factors in plants under salt stress. int. j. genom. 2021: 5578727. shehata, a.m and w.s. nosir. 2019. response of sweet basil plants (ocimum basilicum, l.) grown under salinity stress to spraying seaweed extract. future j. biol. 2: 16-28. shemi, r., r. wang, e.s. gheith, h.a. hussain, s. hussain, m. irfan, l. cholidah, k. zhang, s. zhang and l. wang. 2021. effects of salicylic acid, zinc and glycine betaine on morpho-physiological growth and yield of maize under drought stress. sci. rep. 11: 3195. tabssum, f., q. zaman, y. chen, u. riaz, w. ashraf, a. aslam, n. ehsan, r. nawaz, h. aziz and s.s. shah. 2018. exogenous application of proline improved salt tolerance in rice through modulation of antioxidant activities. pak. j. agric. res. 32: 140-151. tang, x., x. mu, h. shao, h. wang and m. brestic. 2015. global plant-responding mechanisms to salt stress: physiological and molecular levels and implications in biotechnology. crit. rev. biotechnol. 35: 425-37. yuan, y., j. liu, q. ma, y. gao, q. yang, x. gao and b. feng. 2022. cleaner production of proso millet (panicum miliaceum l.) in salt-stressed environment using re-watering: from leaf structural alleviations to multi-omics responses. j. clean. prod. 334: 130205. yuan, z., q. cao, k. zhang, s.t. ata-ul-karim, y. tian, y. zhu, w. cao and x. liu. 2016. optimal leaf positions for spad meter measurement in rice. front. plant sci. 7: 719. zhu, m., q. li, y. zhang, m. zhangand and z. li. 2022. glycine betaine increases salt tolerance in maize (zea mays l.) by regulating na+ homeostasis. front. plant sci. 13: 978304. zou, c.s., l.t. li, d. miki, d.l. li, q.m. tang, l.h. xiao, s. rajput, p. deng, l. peng, w. jia, r. huang, m.l. zhang, y.d. sun, j.m. hu, x. fu, p.s. schnable, yx. chang, f. li, h. zhang and h. zhang. 2019. the genome of broomcorn millet. nat. commun. 10: 436. blank page bangladesh agron. j. 2025, 28(2): 46-56 synergistic effects of biochar and vermicompost on yield and quality of potato b. r. biswas1, f. akhter1, p. roy2, u. sarker2, a. roy3 and t. s. roy1* 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2faculty of agriculture, sher-e-bangla agricultural university, dhaka-1207, bangladesh 3 institute of seed technology, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: tuhinsuvraroy@sau.edu.bd (received: 19 october 2025, accepted: 22 november 2025) keywords: chips, dry matter, potato, reducing sugar, starch abstract poor-quality potatoes are the key constraint on growth and development of bangladesh's potato processing industry. this study aims to investigate the potential benefits of using vermicompost and biochar in conjunction with recommended dose of fertilizers (rdf) to improve potato yield and quality. the research study was performed at the research field of sher-e-bangla agricultural university (sau) in dhaka, bangladesh, from november 2023 to april 2024. the study utilized a split-plot design with three replications to assess the impacts of four different levels of biochar (b) and vermicompost (vm): b1 (0 t ha−1), b2 (1.5t ha−1), b3 (3.0 t ha−1), and b4 (4.5 t ha−1), and vm1 (0 t ha−1), vm2 (1.5 t ha−1), vm3 (3.0 t ha−1), and vm4 (4.5 t ha−1) on yield and quality of potato. the results demonstrated significant effects of biochar and vermicompost on a wide range of yield and quality parameters studied in this experiment. all of these trends were generally positive, with an increase in the amount of applied biochar and/or vermicompost, except for a decrease in reducing sugar content, which is harmful constituent of potato. among the treatment combinations, b4vm4 produced the highest tuber yield at 32.47 t ha−1 with its corresponding marketable yield at 32.07 t ha−1 and yield of potato suitable for french fry production at 6.37 t ha−1. it is statistically comparable to the b4vm3, b3vm4, and b3vm3. the quality in terms of specific gravity and starch content was higher in b4vm4 with 1.068 g cm−3 and 18.45 mg g−2 fresh weight, respectively. however, b4vm3, b3vm4, and b3vm3 are statistically comparable. so, potato farmers can use 3 tons per hectare of biochar and vermicompost, in addition to rdf, which includes 325-220-250-120-14 kg ha−1 of urea, tsp, mop, gypsum, and zinc sulfate for producing good quality potato without sacrificing yield. introduction in bangladesh, the annual potato demand is approximately 8.0 million tons, while the production reaches 11.0 million tons, resulting in a surplus of around 5.0 million tons (jannat et al., 2021). however, a significant portion of these potatoes fail to meet the necessary processing criteria, rendering them unsuitable for export or industrial processing, bangladeshi exporters have successfully exported about 1.03 million tons of fresh potatoes in the fiscal year 2013-14, but exports have since declined to around 80,000 tons per year since fiscal year 2021-22, primarily due to a shortage of export-grade potatoes (bbs, 2022). the quality of potato tubers is a crucial factor for both consumer and industrial demand. quality is assessed based on specific gravity (≥1.06%), dry matter content (≥20%), starch content (≥13%), and reducing sugar concentration (<0.30%) (solaiman et al., 2015). manufacturers prefer high-specific gravity potatoes for various processing applications, as they are crispier and more suitable for mashing, baking, frying and french fry production (lal et al., 2023). roy et al. (2017) found that the dry matter, starch, reducing sugar, non-reducing sugar, and total sugar levels of 40 synergistic effects of biochar and vermicompost on yield and quality of potato 47 potato varieties in bangladesh varied from 13.56 to 24.6 %, 6.8 to 18.93 %, 0.02 to 0.61%, 0.09 to 0.53% and 0.27 to 0.78%, respectively. bangladeshi potato growers often struggle to meet international quality standards due to a lack of sufficient information on the appropriate utilization of organic and chemical fertilizers. to achieve long-term improvement in potato productivity, it is necessary to utilize both organic and inorganic nutrient sources for effective soil fertility management. biochar is a solid residue produced through pyrolysis, enhances soil properties by increasing its ph, cation exchange capacity (cec), enzymatic activity, and the accessibility of nutrients such as nitrogen (n), phosphorus (p), potassium (k), calcium (ca) and magnesium (mg) (tomczyk et al., 2020). applying biochar at a rate of 10 t ha−1 increases the levels of soil organic carbon and available nitrogen, phosphorus, and potassium by 40.5, 23.1, 15.2 and 30.5 %, respectively, in soils after harvesting (premalatha et al., 2022). in addition, studies have shown that biochar, utilized with inorganic fertilizers, has significant agronomic advantages in terms of crop growth and productivity, especially in soils with low fertility. this is achieved either by directly providing nutrients or by improving the availability of nutrients in the soil (alkharabsheh et al., 2021). vermicompost, an effective organic fertilizer made from agricultural waste, boosts crop yield and improves the quality of agricultural products by enhancing soil npk levels, water-holding capacity, and overall productivity (kamar and yaacob, 2022). it improves soil aeration and provides essential macronutrients and micronutrients for crop growth and development (oyege and bhaskar, 2023). the application of vermicompost at a rate of 12.5 t ha-1 resulted in higher yield and growth (mostofa et al., 2021). in order to achieve long-term and environmentally friendly crop production with high yield and quality, it is crucial to prioritize the cultivation of agronomic crops using organic inputs. this approach will effectively improve soil productivity. the present study seeks to examine the impacts of biochar and vermicompost on both the quantity and quality of potatoes. materials and methods the research field of sher-e-bangla agricultural university (sau), dhaka-1207, was the location where the investigation was conducted between november 2023 and march 2024. the site of study is located at latitude 23°7'n and longitude 93°e, having an altitude of 8.6 m above sea level, which lies within the “madhupur tract” agro-ecological zone (aez-28) (chakma et al., 2020). two factors were involved in this experiment: factor a: biochar levels (4) – b1: control (0 t ha−1), b2: 1.5 t ha−1, b3: 3.0 t ha−1, b4: 4.5 t ha−1. factor b: vermicompost levels (4) – vm1: control (0 t ha−1), vm2: 1.5 t ha−1, vm3: 3.0 t ha−1, vm4: 4.5 t ha−1. the variety used for testing was bari alu-25 “asterix”. a split-plot experimental design with three replications was adopted where biochar levels were assigned to main plots and vermicompost levels to the sub-plots. the soil of this experimental field had sandy loam texture having initial properties as follows: ph 5.67; ec 3.00 ds m−1; organic carbon 0.44%; organic matter 1.09%; total nitrogen content 0.14%; exchangeable k content 0.16 meq 100g soil−1; available p amounting to 7.34 mg g−1 soil; available s amounting to 28.75 mg g−1 soil; b content at 0.57 mg g-1 and zn level at 4.62 mg g−1. fertilizer application was done according to recommended rates: urea at 325 kg ha−1, tsp at 220 kg ha−1, mop at 250 kg ha−1, gypsum at 220 kg ha−1, zinc sulfate at 14 kg ha−1, respectively (rahman et al., 2008). biochar and vermicompost were applied after final plot preparation. one third urea along with full tsp, mop and gypsum were applied in furrow apart from 5 cm of planted tuber. the rest amount of urea was applied at 35 and 50 days after planting (dap) as top dressing. the properly sprouted, healthy and uniform sized (60-70 g) seed potato tubers were planted. the plot size was 5.0 m × 2.0 m and 60 cm × 20 cm spacing was maintained. seed potatoes were planted on an average 5 to 6 cm depth in the soil. all the intercultural operations and plant protection standards were taken as per tuber crops research centre (tcrc) 48 biswas et al. recommendation. haulm pulling was done at 90 dap when the majority of plants showed senescence and the top portion started drying. after haulm pulling, the tubers were kept under the soil for 10 days for skin hardening. the potatoes of each plot were separately harvested, bagged, tagged and brought to the laboratory for further analysis. yield and quality contributing parameters were calculated as per following procedure. yield for canned potato production (20-30 mm in size) the tubers are 20 to 30 mm of their diameter size. nahid et al. (2023) were considered for canned tuber and then the entire tuber weighted by using an electronic balance from total tuber yield against each plot. then the means were taken in tons per hectare unit. yields of potato for flakes production (30-45 mm in size) the tubers had a diameter of 30 to 45 mm each. nahid et al. (2023) were considered for flakes tuber and then the entire tuber weighted by using an electronic balance from total tuber yield against each plot. then the means were taken in tons per hectare unit. yield of potatoes for chip production (45-75 mm in size) the tubers are 45 to75 mm in diameter. for chips tuber, nahid et al. (2023) were looked at, and then the whole tuber was weighted by using an electronic balance to compare the total tuber yield to each plot. then the means were taken in tons per hectare unit. yield of the potato for french fry production (>75 mm) the tubers were then considered for french fries, >75 mm of their length, according to nahid et al. (2023) and the yield against each plot was considered from the total tuber yield. an electronic balance was used to weigh the entire tuber, after which the mean in tons per hectare was taken. specific gravity (g cm−3) specific gravity was measured by using the following formula of gould (1995). five tubers were taken from each plot after harvest of the treatment and then the means were taken. specicifc gravity ( g cubic centimeter ) = weight of tuber in air weight of equal volume of water at 4°c dry matter content (dmc, %) the potato tuber samples were kept in separate envelopes for each plot and five potato tubers were taken after harvest to calculate the dmc and were oven dried at 70 °c for 72 h. dry weight was determined with a digital balance and means were calculated in percent unit. dmc= dry weight fresh weight × 100 starch content the starch content of potato tuber was estimated by the standard procedure (shigematsu et al., 2017). reducing sugar (mg g−1 fw) immediately after the harvest, within 10 days, the reducing sugar content of tubers was estimated by the method of somogyi-nelson. the content was calculated using the glucose standard curve at abs660nm (abs1) (shigematsu et al., 2017). synergistic effects of biochar and vermicompost on yield and quality of potato 49 statistical analysis the data collected on different parameters were analyzed statistically by using the technique of analysis of variance with the help of the wasp (web agri stat package: version 1) computer program, and the means were adjusted by using lsd at 5% level of probability (gomez and gomez, 1984). results and discussion the tables contain data on both the yield and quality parameters of potato. the results have been discussed, and potential explanations are presented under the specified categories. tuber numbers hill−1 the number of tubers per hill was not statistically significant because of variations in biochar levels (table 1). table 1. effect of biochar and/ or vermicompost on the yield and yield contributing traits of potato . values with common letter (s) within a column do not differ significantly at 5% level of probability ** & * indicate significant at 1% and 5% level of probability; ns=non-significant, b1: 0 t ha−1, b2: 1.5 t ha−1, b3: 3.0 t ha−1, and b4: 4.5 t ha−1. vm1: control (0 t ha−1), vm2: 1.5 t ha−1, vm3:3.0 t ha−1and vm4: 4.5 t ha−1 as shown in table 1, the application of vm did not have a significant effect on the number of tubers per hill. b4vm3 and b3vm2 yielded the highest numerical value (12.33). according to the available research, an increase in stem numbers corresponds to an increase in tuber biochar level no. of tubers hill−1 average weight of tuber (g) tuber yield (t ha−1) marketable yield (t ha−1) b1 11.50 38.01 d 25.30 c 23.47 c b2 11.48 41.62 c 27.63 b 24.88 b b3 11.83 44.55 b 29.22 a 27.45 a b4 12.00 46.97 a 29.63 a 27.94 a cv (%) 5.63 6.21 5.24 5.14 lsd (0.05) 1.217 0.581 0.668 significance level ns * ** * vermicompost level vm1 11.17 37.69d 23.85 d 19.21 c vm2 11.75 41.09c 27.54 c 25.94 b vm3 12.00 45.29b 29.77 b 28.95 a vm4 11.83 47.07 a 30.62 a 29.64 a cv (%) 8.82 3.87 2.77 3.16 lsd (0.05) 1.395 0.653 0.695 significance level ns ** ** ** biochar × vermicompost b1 × vm1 11.00 32.53 22.13 e 17.47 g b1 × vm2 11.33 36.47 24.17 d 23.83 d b1 × vm3 11.67 40.17 26.63 c 25.53 c b1 × vm4 12.00 42.87 28.27 b 27.03 b b2 × vm1 10.67 36.17 23.90 d 18.63 fg b2 × vm2 11.67 39.87 28.27 b 26.47 bc b2 × vm3 12.00 44.90 28.83 b 26.97 b b2 × vm4 11.33 45.53 29.53 b 27.47 b b3 × vm1 11.00 39.53 24.57 d 19.63 f b3 × vm2 12.33 41.83 28.47 b 26.53 bc b3 × vm3 12.00 46.93 31.63 a 31.63 a b3 × vm4 12.00 49.90 32.20 a 32.00 a b4 × vm1 12.00 42.53 24.80 d 21.10 e b4 × vm2 11.67 46.20 29.27 b 26.93 b b4 × vm3 12.33 49.17 31.97 a 31.67 a b4 × vm4 12.00 49.97 32.47 a 32.07 a cv (%) 8.82 3.87 2.77 3.16 lsd (0.05) ------1.269 1.374 significance level ns ns * * 50 biswas et al. production. on the contrary, the yield of potatoes is dependent on the number and average weight of tubers (koch et al., 2020). the average weight of tuber the average weight of tubers was found to be statistically significant (p≤0.01) when varied quantities of biochar and/or vermicompost were applied (table 1). in both situations, the average weight of tubers scaled gradually as their levels increased. the beneficial impact of combining inorganic fertilizers with organic manures may have contributed to the rise in average weight of potato tubers. this combination probably encouraged increased vegetative growth, resulting in the synthesis of a larger quantity of food material (linus and irungu, 2004). subsequently, these nutrients were transferred to the growing tubers, which resulted in an increase in their weight. in a study of dewi et al. (2024), it was shown that the application of biochar resulted in a significant increase in the weight of tubers. overall, the 16 treatment combinations did not significantly differ in the average weight of potato tubers (table 1). out of the 16 treatment combinations, the b4vm4 combination had the greatest average weight of tuber, which was 49.97 g. on the other hand, the b1vm1 combination had the lowest average tuber weight, which was 32.53 g (table 1). tuber yield the tuber yield was significantly influenced (p≤0.01) by the application of varied amounts of biochar and vermicompost. table. 1. as the quantities of biochar and vermicompost increased, the tuber yields consistently increased. a statistically significant difference (p≤0.01) in potato tuber yield was observed among the treatment combinations, as shown in table 1. the b4vm4 combination had the highest tuber yield, which was statistically comparable to b4vm3, v3vm4, and v3vm3. conversely, v1vm1 showed the lowest tuber yield. the tuber yield per hectare was highest due to the biggest number of tubers per hill and the maximum average weight of each tuber. the application of biochar and vermicompost solubilizes plant nutrients, increasing npk uptake and leading to an increase in tuber yield (chaudhari et al., 2021). additionally, the incorporation of biochar or vermicompost would have enhanced the nutrient content of soil and ability to retain water. according to research, as the amount of biochar increased, both the total yield and marketable yield of potatoes increased gradually (roy et al., 2021). in a study, it was found that adding biochar to the soil improved its cation exchange capacity (cec) and ability to hold water. this led to a 16-35% rise in grain yield compared to the control group (khan et al., 2024). marketable yield marketable yield of tuber was found significant (p≤0.01) against the different biochar and vermicompost levels (table-1). a study shown that using 10 t ha−1 biochar improved both the production and growth of vegetable crops the most (singh et al., 2019). a statistically significant (p≤0.01) variance was observed among the treatment combinations in relation to the marketable yield of potato tubers, as shown in table 1. the v4vm4 treatment combination achieved the highest yield of 32.07 t ha−1, which was statistically equivalent to the yields of the v4vm3, v3vm4, and v3vm3 treatments. the v1vm1 treatment produced the lowest amount, measuring 17.47 metric tons per hectare. the application of fertilizer nutrients could have resulted in an increase in the marketable potatoes. this is due to improved growth, increased foliage and leaf area, and an abundant supply of photosynthates. these factors contribute to the production of larger tubers, ultimately resulting in a higher yield (boubaker et al., 2023). yield for canned potato production the application of different levels of biochar has a significant effect on canned potato production. the b1 treatment recorded the highest production at 2.24 t ha−1, followed by b2, synergistic effects of biochar and vermicompost on yield and quality of potato 51 while v4 yielded the lowest at 1.82 t ha−1. the study found that as the amount of biochar increased, the yield of canned potatoes dropped. the levels of vermicompost did not have any impact on the output of canned potatoes, as shown by the data presented in table 2. table 2. effect of biochar and/ or vermicompost on the yield of potato or different processing purpose treatments yield for canned potato production (t ha−1) (20-30 mm) yield of potato for flakes production (t ha−1) (30-45 mm) yield of potato for chips production (t ha−1) (45-75 mm) yield of potato for french fry production (t ha−1) (>75 mm) biochar level b1 2.24 a 5.66 a 14.41 d 1.54 d b2 2.03 b 4.53 b 15.02 c 3.30 c b3 1.88 c 4.38 c 17.08 b 4.12 b b4 1.82 c 3.92 d 17.83 a 4.94 a cv (%) 2.31 3.14 4.52 2.01 lsd (0.05) 0.097 0.130 0.582 0.144 significance level ** ** * ** vermicompost level vm1 2.07 4.63 12.41 c 0.944 d vm2 2.01 4.64 15.95 b 3.326 c vm3 1.97 4.69 17.68 a 4.70 b vm4 1.90 4.53 18.29 a 4.92 a cv (%) 2.36 3.54 5.12 4.58 lsd (0.05) -----0.979 0.137 significance level ns ns ** ** biochar × vermicompost b1 × vm1 2.33 4.67 cd 11.84 nf b1 × vm2 2.30 5.59 b 14.40 1.54 j b1 × vm3 2.23 6.10 a 15.10 2.16 i b1 × vm4 2.08 6.30 a 16.30 2.44 h b2 × vm1 2.00 4.80 c 11.40 0.42 k b2 × vm2 2.00 4.60 cd 15.90 3.96 e b2 × vm3 2.10 4.60 cd 16.00 4.20 d b2 × vm4 2.00 4.10 e-g 16.77 4.56 c b3 × vm1 2.00 4.70 cd 12.30 0.63 k b3 × vm2 1.90 4.50 c-e 16.60 3.52 f b3 × vm3 1.80 4.30 d-f 19.50 6.23 ab b3 × vm4 1.80 4.00 fg 19.90 6.30 ab b4 × vm1 1.95 4.33 d-f 14.40 2.73 g b4 × vm2 1.85 3.90 fg 16.90 4.28 d b4 × vm3 1.75 3.75 g 20.10 6.36 a b4 × vm4 1.73 3.70 g 20.20 6.37 a cv (%) 2.36 3.54 5.12 4.58 lsd (0.05) ---0.437 ---0.277 significance level ns * ns ** values with common letter (s) within a column do not differ significantly at 5% level of probability ** & * indicate significant at 1% and 5% level of probability; ns=non-significant, b1: 0 t ha−1), b2: 1.5 t ha−1, b3: 3.0 t ha−1, and b4: 4.5 t ha−1. vm1: control (0 t ha−1), vm2: 1.5 t ha−1, vm3:3.0 t ha−1and vm4: 4.5 t ha−1. the correlation between biochar and vermicompost levels did not have a statistically significant impact on canned potato yield. the highest yield of canned potatoes was documented quantitatively from b1vm1, equal to 2.33 t ha−1. yield of potato for flakes production the tuber yield for flakes production showed a significant difference (p≤0.01) when various levels of biochar were applied. however, the application of vermicompost did not yield 52 biswas et al. any significant effect. the b1 treatment had the maximum output of 5.66 t ha−1, whereas the b4 treatment had the lowest yield of 3.92 t ha−1. a significant difference (p ≤0.01) was found among the treatment combinations in terms of the yield of potato tubers for the production of flakes. the treatment combination b1vm4 yielded the largest quantity of 6.30 t ha−1, which was statistically equivalent to the yield produced with the b1vm3 combination. however, the b4vm4 treatment resulted in the lowest yield of 3.70 t ha−1. yield of potato for chips production the tuber yield for chip production was found to be significant (p ≤ 0.01) against the application of different levels of biochar and vermicompost (table 2). in both cases, there was a regular increase in yield in response to increasing levels of biochar and vermicompost application. this finding was consistent with a study which reported that vermicompost increases the availability of nutrients, including micronutrients, in the soil for improved crop nutrient uptake and tuber production (chaudhary et al., 2004). organic fertilizer application increases the availability of both macroand micronutrients in the soil, providing sufficient nutrients to meet crop requirements and thus encouraging the production processes (möller, 2018). the combination of biochar and vermicompost showed no significant variation among the treatment combinations compared to potato tuber yield for chip production (table 2). mathematically, the highest yield (20.20 t ha−1) from b4vm4 was recorded, followed by b4vm3. yield potato for french fry production the yield of tuber for french fry production was found to be significant (p≤0.01) against the application of different levels of biochar and vermicompost (table 2). the results revealed that the yield of potatoes for french fry production gradually increased with increasing biochar and vermicompost levels. the interactive effect of biochar and vermicompost significantly (p≤0.01) influenced the tuber yield for french fry production under study. the highest yield (6.37 t ha−1) was found from b4vm4, which was statistically similar to b4vm3., b3vm4, and b3vm3 (table 2). french fry yield was not found in b1vm1. specific gravity the specific gravity of the tuber changed significantly (p≤0.01) when different amounts of biochar and vermicompost were added (table 3). the results showed a gradual increase in specific gravity as the rate of biochar and vermicompost increased. a similar trend was also observed a study which reported that increased biochar application significantly (p<0.05) increased tuber specific gravity (melo et al., 2022). application of 50% recommended nitrogen, 25% recommended n through fym @ 7.5 t ha−1, and 25% recommended nitrogen through vermicompost @ 2.25 t ha−1 resulted in the maximum specific gravity of potatoes (taha et al., 2017). in terms of interaction effects, a significant (p≤0.01) difference was also found among the treatment combinations against the specific gravity of potato tubers (table 3). the b4vm4 treatment combination yielded the highest specific gravity (1.068 g cm−3), statistically comparable to b4vm3. the b3vm4 and b3vm3 treatment combinations yielded the highest specific gravity, while v1vm1 produced the lowest (0.974 g cm−3). tuber specific gravity increased with increasing organic manure, which is more important to the tuber specific gravity under warmer conditions (shayanowako et al., 2015). dry matter content significant (p≤0.01) variation was noted among the application of different levels of biochar and vermicompost against the dry matter content of tubers (table 3). the (dmc) of potatoes gradually increased as the levels of biochar and vermicompost increased, reaching levels b3 and vm3, and then showing statistically similar results. the result aligned with the findings of a report that observed a significant increase in tuber dry matter content upon the application of synergistic effects of biochar and vermicompost on yield and quality of potato 53 biochar (mostofa et al., 2019). the t4 treatment (crop residue incorporation + biofertilizers (azotobacter and rhizobacteria) + vermicompost @ 5 t ha−1 + microbial culture) yielded a higher dry matter content (19.66%), possibly because the application of vermicompost positively influenced the dry matter of tubers (mostofa et al., 2019). though the combination effects of biochar and vermicompost had no significant effect on dry matter content of tubers, b4vm4, b4vm3, b3vm4 and b3vm3 produced more than 20% dry matter content, which is suitable for processing industries (luthra and gupta, 2019). according to the findings, the model calculations of the fraction of total dry matter produced. however, those allocated to the tuber were on the assumption that the tubers had been the dominant sink in the potato crop (kooman and rabbinge, 1996). table 3. response of biochar and/ or vermicompost on the quality parameter of potato treatments specific gravity (g cm−3) dry matter content (%) reducing sugar (mg g−1 fw) starch content (mg g−1 fw) biochar level b1 1.026 d 18.32 c 0.541 a 14.033 c b2 1.045 c 19.29 b 0.412 b 15.537 b b3 1.052 b 20.56 a 0.330 c 17.603 a b4 1.056 a 20.93 a 0.325 d 17.713 a cv (%) 0.27 3.18 0.24 2.57 lsd (0.05) 0.027 0.780 0.030 0.204 significance level ** ** ** ** vermicompost level vm1 1.018 d 17.61 c 0.492 a 14.333 c vm2 1.046 c 19.58 b 0.411 b 16.355 b vm3 1.055 b 20.70 a 0.364 c 16.929 a vm4 1.060 a 21.22 a 0.341 d 17.268 a cv (%) 0.28 3.26 0.25 2.61 lsd (0.05) 0.028 0.544 0.032 0.357 significance level ** ** ** ** biochar × vermicompost b1vm1 0.974 k 16.05 0.595 a 12.160 g b1vm2 1.035 i 18.65 0.546 b 13.610 f b1vm3 1.045 gh 19.17 0.522 c 14.650 e b1vm4 1.051 ef 19.41 0.502 d 15.712 d b2vm1 1.025 j 17.45 0.497 e 13.670 f b2vm2 1.047 fg 19.57 0.422 g 15.817 d b2vm3 1.051 ef 19.97 0.380 i 16.120 cd b2vm4 1.057 cd 20.16 0.347 k 16.540 c b3vm1 1.031 i 18.16 0.464 f 15.834 d b3vm2 1.053 de 19.92 0.312 l 17.634 b b3vm3 1.064 ab 21.65 0.282 m 18.573 a b3vm4 1.064 ab 22.52 0.262 o 18.370 a b4vm1 1.041 h 18.79 0.412 h 15.670 d b4vm2 1.050 e-g 20.16 0.365 j 18.360 a b4vm3 1.064 ab 21.99 0.271 n 18.373 a b4vm4 1.068 a 22.79 0.251 p 18.450 a cv (%) 0.28 3.26 0.25 2.61 lsd (0.05) 0.025 ---0.028 0.650 significance level ** ns ** * values with common letter (s) within a column do not differ significantly at 5% level of probability ** & * indicate significant at 1% and 5% level of probability; ns=non-significant, b1: (0 t ha−1), b2: 1.5 t ha−1, b3: 3.0 t ha−1, and b4: 4.5 t ha−1. vm1: control (0 t ha−1), vm2: 1.5 t ha−1, vm3:3.0 t ha−1and vm4: 4.5 t ha−1 54 biswas et al. reducing sugar reducing sugar is one of the most harmful constituents of potato, and more than 0.5% reducing sugar may cause toxicity to human health (bethke and bussan, 2013). a significant variation at p≤0.01 was found among the different levels of biochar and vermicompost application against reducing sugar content of tubers; the values are given in table 3. the results showed that reducing sugar contents decreased with increasing levels of biochar and vermicompost. according to research, sugar content of tuber decreased with increasing levels of biochar and vermicompost application compared to the control treatment (ferdous et al., 2019). this study also reported that increasing vermicompost levels significantly decreased tuber-reducing sugar content. the treatment combination of biochar and vermicompost showed a significant (p≤0.01) variation that was found among the treatment combinations against reducing sugar content of potato tubers (table 3). the lowest reducing sugar (0.251 mg g−1 fw) was found from b4vm4 treatment combination. the combination of b4vm3, b3vm4, and b3vm3 also contained less than 0.3 mg g −1 fw reducing sugar content, which is suitable for processing products, while the highest (0.595 mg g−1 fw) reducing sugar was in v1vm1. due to the higher application of organic manures, it may decrease the internal respiration of potato stored matter like starch. due to that, the reducing sugar was lower by a slower rate of breaking the starch into less reducing sugars than that of no application of organic manure (shayanowako et al., 2015). starch content significant (p≤0.01) variation was noted among the application of different levels of biochar and vermicompost application against starch content of tuber (table 3). data showed that starch content progressively increased with increasing biochar and vermicompost levels upto b3 and vm3 and after that exhibited statistical similar result. 17.713 mg g−1 fw was found from b4 treatment which was similar to b3 treatment and the less significant (p≤0.05) variation was also found among the treatment combinations against starch content of potato tubers (table 3). the maximum starch (18.450 mg g−1 fw) was found from b4vm4 treatment combination which was statistically at par with b4vm3, b4 vm2, b3vm4 and b3vm3, where the lowest (12.160 mg g−1 fw) was recorded in b1vm1 (table 3). starch content also varied significantly with organic manures application, they also indicated a judicious trend of starch accumulation in case of application of different levels of organic manures is presented in, which showed similar result of the research (jaipaul et al., 2011). conclusion these results clearly show that the yield and quality parameters of potatoes responded significantly to biochar, vermicompost, or their combination. although different mixes were tried, the best one for potato yield and quality was 3 t ha−1 of both biochar and vermicompost mixed together. this was better than using higher rates of each ingredient separately. it was suggested that 325 kg ha−1 of urea, 220 kg ha−1 of tsp, 250 kg ha−1 of mop, 120 kg ha−1 of gypsum, and 14 kg ha−1 of zinc sulfate be used with 3 t ha−1 of biochar and 3 t ha−1 of vermicompost. this led to the best potato yield and quality. acknowledgment this study was supported by sher-e-bangla agricultural university research system (saures), dhaka, bangladesh. synergistic effects of biochar and vermicompost on yield and quality of potato 55 references alkharabsheh, h.m., m.f. seleiman, m.l. battaglia, a. shami, r.s. jalal, b.a. alhammad. 2021. biochar and its broad impacts in soil quality and fertility, nutrient leaching and crop productivity: a review. agronomy 11(5): 993-1001. bbs. 2020. bangladesh bureau of statistics. statistical yearbook of bangladesh. ministry of planning, government of the people’s republic of bangladesh, dhaka. bethke, p.c. and a.j. bussan. 2013. acrylamide in processed potato products. am. j. potato res. 90: 403–424. boubaker, h., w. saadaoui, h.y. dasgan, n. tarchoun and n.s. gruda. 2023. enhancing seed potato production from in vitro plantlets and microtubers through biofertilizer application: investigating effects on plant growth, tuber yield, size, and quality. agronomy 13(10): 2541. chakma, n., p.k. biswas, p.k. hore and m.r. islam. 2020. effect of seed priming on growth and yield of different wheat varieties in madhupur tract of bangladesh. ijair. 14(5): 45-55. chaudhari, s., a. upadhyay and s. kulshreshtha. 2021. influence of organic amendments on soil properties, microflora and plant growth. sustain. agric. rev. 52:147–191. chaudhary, d.r., s.c. bhandari and l.m. shukla. 2004. role of vermicompost in sustainable agriculture– a review. agric. rev. 25(1): 29–39. dewi, t., j. hamdani and s. mubarok. 2024. response of growth and tuber seed production of g0 potato (solanum tuberosum l.) cv medians in medium lands of jatinangor to biochar composition and retardant type. kultivasi. 23. ferdous, j., t.s. roy, r. chakraborty, m. mostofa, f. nowroz and r. noor. 2019. starch and sugar content of some selected potato varieties as influenced by vermicompost. azarian j. agric. 6(2): 47-57. gomez, k.a. and a.a. gomez. 1984. statistical procedures for agricultural research. john wiley & sons, new york. pp.97-129. gould, w. 1995. specific gravityits measurement and use. chipping potato handbook. pusha publication. 18. jaipaul, j., s. sharma and a.k. sharma. 2011. effect of organic fertilizers on growth, yield and quality of potato under rainfed conditions of central himalayan region of uttarakhand. potato j. 38(2): 12. jannat, a., y. ishiwata and j. furuya. 2021. assessing the impacts of climate variations on the potato production in bangladesh: a supply and demand model approach. sustainability. 13. kamar, z.a.m. and j.s. yaacob. 2022. exploring the potential of vermicompost as a sustainable strategy in circular economy: improving plants’ bioactive properties and boosting agricultural yield and quality. environ. sci. pollut. res. 17: 1–17. khan, s., s. irshad, k. mehmood, z. hasnain, m. nawaz, a. rais, et al. 2024. biochar production and characteristics, its impacts on soil health, crop production, and yield enhancement: a review. plants. 13(2): 166. koch, m., m. naumann, e. pawelzik, a. gransee and h. thiel. 2020. the importance of nutrient management for potato production part i: plant nutrition and yield. potato res. 63(1):97–119. kooman, p.l. and r. rabbinge. 1996. an analysis of the relation between dry matter allocation to the tuber and earliness of a potato crop. ann. bot. 77(3): 235–242. lal, m., r. tiwari, a. jaiswal, r. kumar, d. kumar, d. kumar. 2023. post-harvest management and value addition in potato: emerging technologies in preserving quality and sustainability in potato processing. indian j. agron. 68: 241–261. linus, m.m. and j.w. irungu. 2004. effect of integrated use of inorganic fertilizer and organic manures on bacterial wilt incidence (bwi) and tuber yield in potato production systems on hill slopes of central kenya. j. mt sci. 1: 81–88. luthra, s.k. and v.k. gupta. 2019. development of potato varieties for processing industries—an overview. icar-cent. potato res. inst. reg. stn. nhrdf souvenir. 3:50–61. melo, l.c.a., j. lehmann, j.s. da s. carneiro and m. camps-arbestain. 2022. biochar-based fertilizer effects on crop productivity: a meta-analysis. plant soil. 472(1):45–58. möller, k. 2018. soil fertility status and nutrient input–output flows of specialised organic cropping systems: a review. nutr. cycl. agroecosyst. 112(2):147-164. mostofa, m., t.s. roy and r. chakraborty. 2021. yield and yield contributing attributes of potato as influenced by vermicompost and seed tuber size. saarc j. agric. 19:71-79. 56 biswas et al. mostofa, m., t.s. roy, r. chakraborty, s. modak, p.k. kundu, m.s. zaman. 2019. effect of vermicompost and tuber size on processing quality of potato during ambient storage condition. int. j. plant soil sci. 26(3):1-18. nahid, m., m.a. razzaque, m.n.i.b. bhuiyan, m.a. islam, r. begum and t.s. roy. 2023. effects of nitrogen and potassium on yield and quality of potato (solanum tuberosum l.) cultivars. bangladesh j. bot. 52(2):267-275. oyege, i. and m.s.b. bhaskar. 2023. effects of vermicompost on soil and plant health and promoting sustainable agriculture. soil syst. 7(4):101-112. premalatha, r.p., p. malarvizhi and e. parameswari. 2022. effect of biochar doses under various levels of salt stress on soil nutrient availability, soil enzyme activities and plant growth in a marigold crop. crop pasture sci. 24: 45-52. rahman, m., t. dey, m. ali, s. khalequzzaman and m. hussain. 2008. control of late blight disease of potato by using new fungicides. roy, t.s., b.r. das, n. sultana, r. chakraborty and m.s. rahman. 2021. enhancement of the productivity of processing category potato by biochar. bangladesh agron. j. 24(2):63-72. roy, t.s., r. chakraborty, m.n. parvez, m. mostofa, j. ferdous and s. ahmed. 2017. yield, dry matter and specific gravity of exportable potato: response to salt. univ. j. agric. res. 5(2):98-103. shayanowako, a., r. mangani, t. mtaita and u. mazarura. 2015. influence of main stem density on irish potato growth and yield: a review. annu. res. rev. biol. 5(3):229-237. shigematsu, t., n. furukawa, r. takaoka, m. hayashi, s. sasao, s. ueno. 2017. effect of high pressure on the saccharification of starch in the tuberous root of sweet potato (ipomoea batatas). biophys. chem. 231: 105-110. singh, m., r.k. saini, s. singh and s.p. sharma. 2019. potential of integrating biochar and deficit irrigation strategies for sustaining vegetable production in water-limited regions: a review. hortscience. 54(11):1872-1878. solaiman, a.h.m., t. nishizawa, t.s. roy, m. rahman, r. chakraborty, j. choudhury. 2015. yield, dry matter, specific gravity and color of three bangladeshi local potato cultivars as influenced by stage of maturity. j. plant sci. 10(3):108-115.. taha, m., t.p. malik, a.k. bhatia and s. deswal. 2017. tuber growth and quality of potato var. ‘kufri bahar’ as affected by fym, vermicompost and neem cake under western haryana conditions, india. int. j. curr. microbiol. appl. sci. 6(12):4-118. tomczyk, a., z. sokołowska and p. boguta. 2020. biochar physicochemical properties: pyrolysis temperature and feedstock kind effects. rev. environ. sci. biotechnol. 19(1): 191-215. blank page bangladesh agron. j. 2024, 27(2): 90-95 effect of irrigation intervals and mulching material on the growth and yield of maize m.m. liza1*, m.m. hasan2, m.r.h. khan2, a. saha2, f.h. tuly2 and s.m. masum2 1department of agronomy, habiganj agricultural university, habiganj, bangladesh 2department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: mohshina1990@gmail.com (received: 23 june 2025, accepted: 24 july 2025) keywords: maize, irrigation, mulching materials abstract an experiment was conducted at habiganj agricultural university's research field to study the effects of irrigation and mulching on the yield of maize cultivation in the sylhet region of bangladesh. the study analyzed the effects of different irrigation intervals, i.e., irrigation at 15, 30, and 60 days after sowing (das); at 15, 30, and 85 das; and at 15, 30, 60, and 85 das; along with polythene and jute sack as mulching materials on maize performance. the experiment was laid out in a pot experiment with a randomized complete block design with three replications. results showed that irrigation at 15, 30 and 85 das gave the highest cob length (cm), cob weight plant−1 (g), number of grain cob−1, 100-grain weight (g), and grain yield (t ha−1) while jute sack performed better than mulching with polythene. the interaction effect of irrigation intervals and mulching treatments showed a significant difference in all yield contributing parameters except the number of cob plant−1. the highest cob length (16.57 cm), cob weight plant−1 (143.33 g), number of grain cob−1 (316.65), 100-grain weight (34.33 g), grain weight cob−1 (118.9 g) and grain yield (8.77 t ha−1) were obtained from the interaction of at 15, 30 and 85 das intervals with jute sack mulching whereas the lowest from the no irrigation (control) with jute sack mulching. introduction . in bangladesh, maize is second in production after rice and is ranked third as a staple cereal (islam et al., 2020). in bangladesh, the cultivation of maize has been gaining popularity in recent years because of its high productivity and diversified use (tajul et al., 2013). bangladesh covers about 0.478 million hectares with a production of 4.26 million tonnes of grains (bbs, 2023). the national average yield is only 6.45 t ha−1, which is very low compared with leading maize-growing countries, whereas the newly released varieties can produce more than 8.0 t ha−1 (ais, 2015). proper growth and development of maize need favourable soil moisture up to its root zone. limited water supply during the growing season results in soil and plant water deficits and reduces maize yields (gordon et al., 1995; patel et al., 2006). maize is a crop that requires less water than boro rice and produces consistently much higher yields (ali et al., 2008). the optimum use of irrigation water should be an important strategy for increasing maize production. using mulch in irrigated fields is another crucial element for supporting soil moisture and fostering the growth of plants and yield production (ramalan and nwokeocha, 2000; acharya et al., 2005). plastic film mulch is widely used as a low-cost measure to improve water retention in the soil (wang et al., 2009), increase soil temperature (yi et al., 2010), and reduce soil evaporation (shengxiu and ling, 1992). besides, sack farming, where maize is grown in sacks or bags, can be used as an alternative to mulching. the sacks help maintain soil moisture mailto:mohshina1990@gmail.com 91 liza et al. by reducing evaporation, suppressing weed growth by blocking sunlight and regulating soil temperature to protect maize roots. the main objectives of this research were to determine the effects of different irrigation and mulching materials on the yield and productivity of maize, as well as to identify the most effective combination of irrigation interval and mulching material that maximizes maize yield. materials and methods the experiment was conducted at the agronomy farm of habiganj agricultural university, sylhet, from march 2023 to july 2024. the experimental field located in sylhet division falls under a tropical monsoon climate. during the season (october to march), the region experiences relatively dry conditions with moderately low temperatures. average temperatures during this period range from 13-18°c (lowest in january) to around 25°c in the daytime. rainfall is significantly reduced compared to the kharif-1 season, with only light and sporadic showers. the experiment consisted of two factors viz., factor a: irrigation (4), i.e., i0 = no irrigation, i1 = irrigation at 15, 30 and 60 days after sowing (das), i2 = irrigation at 15, 30 and 85 das, and i3 = irrigation at 15, 30, 60 and 85 das and factor b: mulching materials (2) i.e., m1 = mulching with polythene, m2 = jute sack mulching. the experiment was laid out in a randomized complete block design with three replications within 24 pots., maize var. bari hybrid bhutta-17 was used as plant material, and the seeds were collected from bangladesh agricultural research institute (bari), gazipur. the pots were prepared for the experiment in the first week of march 2024, where the soil textural class was sandy clay loam, having a ph of 5.5. fertilizers and manures were applied for the cultivation of crops as recommended by bari, 2014. the seeds were sown in the pots, having two seeds hole−1. all intercultural operations, like gap filling, thinning, weeding and plant protection, were taken as per recommendation. the thinning was done at 7 das for obtaining one plant pot−1, after that, mulching was done accordingly. the cobs of tested plants of each pot were separately harvested for recording data on yield attributes and other parameters like cob plant−1, cob weight, grain cob−1, test grain weight, and grain yield. the data were analysed, and the means were separated by least significant difference (lsd) at 5% level of significance using the statistical computer package program statistix-10. results and discussion cob length the combined effect of different intervals of irrigation and mulching materials did not significantly influence the cob length (table 1). however, numerically higher cob length of 16.57 cm was observed in i2m2 statistically similar to i3m2 (16.31 cm) and i3m1 (16.02 cm). cob circumference the combined effect of different intervals of irrigation and mulching materials significantly influenced the cob circumference (table 1). results showed that the highest cob circumference (16.57 cm) was observed with the treatment i2m2 (irrigation at 15, 30 and 85 das with jute sack mulching). conversely, the lowest cob circumference (14.27 cm) was found from i0m2 (no irrigation with jute sack mulching), which was statistically similar to i0m1 (14.36 cm). cob weight the combined effect of different intervals of irrigation and mulching materials significantly influenced the cob weight (table 1). considering the interaction effect, the highest cob weight (143.33 g cob−1) was observed for the i2m2 (irrigation at 15, 30 and 85 das with effect of irrigation and mulching on the growth and yield of maize 92 jute sack mulching) closely followed by i3m2 (134.67 g cob−1). in contrast, the lowest cob weight of 63.00 g cob−1 was recorded for the combination i0m2 (no irrigation with jute sack mulching). grains number cob−1 the number of grains cob−1 was maximum in i2m2 (316.65), closely followed by im2 and i3m1. islam et al. (2022) also concluded that the grains number cob−1 was significantly influenced by mulching and irrigation, with the highest from three irrigations combined with mulching. 100-seed weight the combined effect of different intervals of irrigation and mulching materials as was non-significantly influenced the 100-seed weight (table 1). 100-seed weight was observed to be almost the same in all the combinations of treatments, in which the slightly higher seed weight was found for the treatment i2 m2 (34.33 g). table 1. interaction effect of different intervals of irrigation and mulching materials on the yield parameters of yellow maize treatments cob length (cm) cob circumference (cm) cob weight (g cob−1) grains number cob−1 100-grain weight (g) grain weight (g cob−1) i0m1 14.68 ab 14.36 c 77.00 bc 254.66 c 30.67 a 51.48 f i0m2 14.23 b 14.27 c 63.00 c 241.98 c 30.33 a 40.88 g i1m1 15.59 ab 15.33 bc 101.33 a-c 264.42 bc 31.33 a 67.48 e i1m2 15.35 ab 15.51 ab 110.33 a-c 266.97 bc 31.33 a 72.59 de i2m1 15.25 ab 15.30 bc 126.67 ab 292.86 ab 32.00 a 90.46 c i2m2 16.57 a 16.57 a 143.33 a 316.65 a 34.33 a 118.90 a i3m1 16.02 ab 15.54 ab 127.67 ab 298.47 a 32.00 a 80.20 d i3m2 16.31 ab 15.76 ab 134.67 a 299.87 a 32.33 a 105.29 b lsd (0.05) 2.2410 1.13 52.44 31.05 4.43 7.69 cv% 8.26 4.22 27.10 6.34 7.96 5.60 in a column, means having a similar letter(s) are statistically similar, and those having dissimilar letters (s) differ significantly at the 0.05 level of probability. i0 = no irrigation; i1 = irrigation at 15, 30 and 60 das; i2 = irrigation at 15, 30 and 85 das; and i3 = irrigation at 15, 30, 60 and 85 das; m1 = mulching with polythene, m2 = jute sack mulching grain weight cob−1 grain weight was significantly influenced by the integrated effect of different intervals of irrigation and mulching materials (table 1). the highest grain weight per cob of 118.90 g was from i2m2 (irrigation at 15, 30 and 85 das with jute sack mulching), while the lowest grain weight per cob of 40.88 g was associated with i0 m2 (no irrigation with jute sack mulching). the research findings are similar to mahajan et al. (2007), who described that mulch contributes to maintaining the high yield of plants by increasing the grain weight cob−1. 93 liza et al. fig 1. effect of irrigation intervals and mulching materials on grain weight of per yellow maize cob. grain yield grain yield was significantly influenced by the integrated effect of different intervals of irrigation and mulching materials (table 1). results showed that the maximum grain yield of 8.77 t ha−1 was found from i2m2 (irrigation at 15, 30 and 85 das with jute sack mulching) while the minimum grain yield 2.87 t ha−1 was observed in i0m2 (no irrigation with jute sack mulching), which was statistically similar to i0m1 (3.37 t ha−1). limited soil moisture hinders crop growth, reducing grain yields. just six days of irrigation affect grains per cob, weight, length, and leaf area. shorter grain-filling and faster ripening result in small, wrinkled seeds. water stress restricts photosynthesis for fertilized grains due to grain abortion, leading to fewer and atrophied grains. it also causes premature male flowering, shortens growth stages, forcing plants to mature and produce grains faster. these results support conclusions drawn by numerous other researchers (ferdoush et al., 2017). the combined application of frequent irrigation and organic mulch produced the highest yields, indicating a synergistic interaction between the two practices. this combination likely optimized soil moisture availability while minimizing losses due to evaporation, leading to favourable conditions for root growth and nutrient uptake. between the mulching materials tested, jute sack mulch was found to be more effective than inorganic plastic in maintaining soil moisture, moderating temperature fluctuations, and suppressing weeds. organic mulch also contributes to soil organic matter upon decomposition, thus enhancing soil fertility in the long term. plastic mulch, while effective in reducing surface evaporation and promoting early growth, had limitations related to soil aeration and long-term environmental sustainability. 0 20 40 60 80 100 120 140 i0 m1 i0 m2 i1 m1 i1 m2 i2 m1 i2 m2 i3 m1 i3 m2 g ra in w ei g h t co b − 1 (g ) treatments i=irrigation; m=mulching effect of irrigation and mulching on the growth and yield of maize 94 fig 2. effect of irrigation intervals and mulching materials on grain yield (t ha−1) of yellow maize. conclusion the study was found that the combination of irrigation and mulching materials significantly influenced grain yield. the maximum yield was 8.77 t ha−1 with the irrigation at 15, 30 and 85 das with jute sack treatment. limited soil moisture and water stress can reduce grain yields, leading to smaller corn cob size and reduced grain production. jute sack mulch was found to be more effective than inorganic plastic in maintaining soil moisture, reducing weeds, and enhancing soil fertility. this finding was generated from pot trial so it should be done at onstation as well as on-farm trial for validation with cost-benefit analysis. references acharya, c.l., k.m. hati, k.k. bandyopadhyay, d. hillel, c. rosenzweig, d.s. pawlson, k.m. scow, m.j. sorger, d.l. sparks, and j. hatfield. 2005. encyclopedia of soils in the environment. inchief daniel hillel, columbia university, ny, usa. ais (agriculture information service). 2015. area, production and yield of different crops. agriculture information service, ministry of agriculture, government of the people’s republic of bangladesh, khamarbari, dhaka, bangladesh. pp.14. ali, m.y., s.r. waddington, j. timsina, d.p. hodson and j. dixon. 2008. maize-rice cropping systems in bangladesh: status and research opportunities. agric. sci. technol. 3(6): 35-53. bbs (bangladesh bureau of statistics). 2023. statistical yearbook of bangladesh 2022, statistics & informatics division, ministry of planning, government of the people’s republic of bangladesh, dhaka, bangladesh. pp. 134. ferdoush, a., m.a. haque, m.m. rashid and m.a.a. bari. 2017. variability and traits association in maize (zea mays l.) for yield and yield associated characters. j. bangladesh agric. univ. 15(2): 193-198. gordon, w.b., r.j. raney, and l.r. stone. 1995. irrigation management practices for corn production in north central kansas. j. soil water conserv. 50(4): 395-399. islam, m.s., m.k. alam, n. salahin, m.j. alam, m.a.m. hussen and a.t.m.a.i. mondol. 2022. effects of tillage, mulch and irrigation on maize (zea mays l.) yield in drought prone area. bangladesh j. agric. 47(1): 27-38. islam, s., a. ferdausi, a.y. sweety, a. das, a. ferdoush and m.a. haque. 2020. morphological characterization and genetic diversity analyses of plant traits contributed to grain yield in maize (zea mays l.). j. biosci. agric. res. 25(1): 2047-2059. 0 1 2 3 4 5 6 7 8 9 10 i0 m1 i0 m2 i1 m1 i1 m2 i2 m1 i2 m2 i3 m1 i3 m2 g ra in y ie ld ( t h a -1 ) treatments i=irrigation; m=mulching 95 liza et al. mahajan, g., r. sharda, a. kumar and k.g. singh. 2007. effect of plastic mulch on economizing irrigation water and weed control in baby corn sown by different methods. african j. agric. res. 2(1): 19-26. patel, j.b., v.j. patel and j.r. patel. 2006. influence of different methods of irrigation and nitrogen levels on crop growth rate and yield of maize (zea mays l.). indian j. crop sci. 1(1 and 2): 175-177. ramalan, a.a. and c.u. nwokeocha. 2000. effects of furrow irrigation methods, mulching and soil water suction on the growth, yield and water use efficiency of tomato in the nigerian savanna. agric. water manag. 45(3): 317-330. shengxiu, l. and x. ling. 1992. distribution and management of drylands in the people’s republic of china. adv. soil sci. 18:147-302. tajul, m.i., m.m. alam, s.m.m. hossain, k. naher, m.y. rafii and m.a. latif. 2013. influence of plant population and nitrogen‐fertilizer at various levels on growth and growth efficiency of maize. sci. world j. 2013(1). 193018. doi: 10.1155/2013/193018. wang, y., z. xie, s.s. malhi, c.l. vera, y. zhang and j. wang. 2009. effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi-arid loess plateau, china. agric. water manag. 96(3): 374-382. yi, l., y. shenjiao, l. shiqing, c. xinping and c. fang. 2010. growth and development of maize (zea mays l.) in response to different field water management practices: resource capture and use efficiency. agric. for. meteorol. 150(4): 606-613. bangladesh agron. j. 2022, 25(2): 119-127 effect of exogenous salicylic acid and silicon application on salinity tolerance of rice s.a. rima, u. somaddar, s.c. samanta and g. saha* department of agronomy, patuakhali science and technology university, dumki, patuakhali, 8602, bangladesh corresponding e-mail: gopalagr@pstu.ac.bd (received: 17 december 2022, accepted: 27 february 2023) keywords: na+ and k+ accumulation, rice, salicylic acid, salinity tolerance, silicon abstract soil salinity remarkably hinders rice growth, development and productivity. the present study was set up to explore the role of exogenous salicylic acid (sa) and silicon (si) application on the growth and yield performance of two contrasting rice genotypes, namely brri dhan41 (salt-tolerant) and brri dhan49 (salt-sensitive) under salinity. the experiment was laid out in a randomized complete block design with three replications and four sa and si treatments such as control (tap water), 100 ppm sa, 100 ppm si (as casio3) and, co-application of sa and si (50 ppm each). results revealed that the maximum plant height (125.2 cm), fresh weight of shoot (267.3 g) and maximum k+/na+ (5.2) were obtained in brri dhan49 after sole application of si under salt stress. besides, the number of grains per panicle and grains per hill significantly increased in brri dhan41 after the sole application of sa (64 and 46%, respectively) and co-application of sa and si (29 and 21%, respectively), and in brri dhan49 with sole sa (182 and 277%, respectively) and si (75 and 446%, respectively) compared with their respective controls. besides, we observed that the k+/na+ was increased where the shoot accumulation of na+ reduced significantly in both rice varieties after sole and co-application of sa and si compared with the untreated plants. however, the present findings showed new dimensions regarding the beneficial effects of si on rice plants which could effectively be utilized to grow and maximize rice production in the saline-prone coastal areas of bangladesh encountering detrimental effects of salt stress on rice. introduction the currently cultivated rice (oryza sativa l.) varieties are facing significant yield reductions due to the increasing trend of soil salinity in the coastal regions of bangladesh (ahmed and haider, 2014). though rice has a widespread geographic distribution but the production of rice is very low due to its vulnerability to climate change. in addition to reducing plant growth, photosynthesis, biomass, yield, and water usage efficiency, high salinity also causes physiological drought as well as ion toxicity in plants, which lowers nutrient availability by reducing their osmotic potential (dos santos et al., 2022; akram and ashraf, 2011). shoot and root growth has been significantly reduced in rice plants due to high osmotic stress (shrivastava and kumar, 2015). salinity reduced the number of spikelets and grains thus causing poor grain yield (saqib et al., 2012). the most important and injurious effect of salinity is the accumulation of sodium ion (na+) and chloride ion (cl-) in plant tissues (nishimura et al., 2011). wang et al. (2019) reported that several adaptation and mitigation strategies have been employed to overcome the mailto:gopalagr@pstu.ac.bd 120 rima et al. harmful effect of high soil salinity in plants. among them, the exogenous application of salicylic acid (sa) and silicon (si) already gained considerable attention in alleviating the salinity-induced negative effects. sa is one of the plant growth regulators that provide protection against salinity (husen et al., 2018). several morpho-physiological and biochemical processes like growth, ethylene production, photosynthesis, flowering and nitrate metabolism have been reported to be regulated by sa (hayat et al., 2010). besides, si is known as the second most plentiful element in soil and widely known as beneficial element for plants (epstein, 1999; liang et al., 2015). si application has mitigating effects on salinity-induced negative impacts in different plant species including rice (somaddar et al., 2022), barley (khan et al., 2019), wheat (singh et al., 2022), sorghum (hurtado et al., 2020). according to abro et al. (2009), application of si increased plant height in rice and wheat, respectively. importantly, si treatment has been reported to reduce na+ uptake and enhanced k+/na+ ratio in plants under salinity stress (garg and bhandari, 2015). considering the fact stated above, this study was undertaken to evaluate the effect of foliar application of sa and si in mitigating the salinity-induced negative impacts in rice. materials and methods the experiment was carried out at the field laboratory and stress agronomy laboratory, department of agronomy and central laboratory of patuakhali science and technology university, bangladesh. the experiment area was located at the coordinates of 22°37' n latitude and 89°10' e longitude under ganges tidal floodplain argo-ecological zone-13. the experiment was carried out in a factorial randomized complete block design (rcbd) where two rice varieties viz., brri dhan41 and brri dhan49 were used as factor a and exogenous application of 100 ppm sa (salicylic acid), 100 ppm si (in the form of casio3) and coapplication of sa and si (50 ppm each) as factor b. a control treatment (tap water) was included with factor b to compare the treatment and non-treatment effects on the growth parameters of rice genotypes with three replications. sa and si solutions were foliar sprayed. a surfactant tween-20 at concentration of 0.5% (v/v) was added with sa and si solution. the exogenous sa and si application was done two times (60 and 80 days after sowing). the experiment was set up in plastic pots using the soil culture method and the soil was sandy loam. urea, triple superphosphate, muriate of potash, gypsum, and zinc sulphate fertilizers were added to the soil according to the recommended dosage (frg, 2018). four to five pregerminated seeds were planted in soil and two seedlings having uniform growth were kept. subsequently, the soil salinization was introduced using table salt (nacl) in the form of irrigation water. we used 5.0 g nacl per liter of tap water to treat the rice plants with saline water having an ec of approximately 9.8-10 ds/m. saline irrigation was applied six (6) times at 7-day interval starting from 45 days of rice seedlings after sowing. at the same time, the control plants were treated with tap water only. the important growth and yield attributes like plant height, root length, number of effective tillers, fresh and dry biomass, grain yield, as well as shoot na+ and k+ contents were recorded following the basic principles. briefly, the amount of na+ and k+ in the rice shoots was measured following the procedure as described by krishnamurthy et al. (2016). rice shoot sample of 0.5 g was used for digestion with 10 ml of the di-acid mixture (2:1 of nitric acid and perchloric acid). then properly digested leaf sample’s volume was made up to 100 ml with distilled water in a 100 ml volumetric flask. effect of exogenous salicylic acid and silicon application on salinity tolerance of rice 121 after filtering the solution by whatman filter paper grade-42 the amount of na+ and k+ was measured using a flame photometer (biobase, model: bk-fp640). the effects of treatments means were compared using tukey's honestly significant difference (hsd) using computer based statistical program jmp 8 (jmp®8, sas institute inc., cary, nc, 1989-2019). results and discussion effect of exogenous of sa and si on different growth characters of rice under salt stress plant height and root length the foliar application of sa and si significantly enhanced plant height by 28 and 29%, respectively in brri dhan49 as compared with control, which were statistically similar (figure 1a). the lowest plant height (88 cm) was observed in brri dhan41 after the co-application of sa and si which was statistically similar to the control. it was also noticed that plant height of brri dhan49 under saline medium increased by 13% while treated with sa alone and no significant difference was observed after sole application of si and co-application of sa and si over control (figure 1a). in case of the salt-tolerant var. brri dhan41, root length was significantly increased by 25 and 11% after sole application of sa and si compared with the control. contrastingly, in the sensitive brri dhan49, the root length reduced significantly by 22% while treated with sa and si together, and no significant effect was observed due to the sole application of sa and si over control under saline condition (figure 1b). several studies also showed that plant height and root length significantly reduced under salt stress, which was subsequently ameliorated by the application of sa (jini and joseph, 2017; mahdieh et al., 2015; ali and mahmoud, 2013). fig. 1. effect of salicylic acid (sa) and silicon (si) on (a) plant height and (b) root length of rice under salt stress (10 ms cm-1). effective tillers per hill the variety brri dhan41 had no significant difference in the number of effective tillers per hill after the sole and co-application of sa and si. whereas, the sensitive variety brri dhan49 remarkably increased effective tillers per hill by 206 and 163%, respectively after sole application of sa, and co-application of sa and si over control plants under salt stress (figure 2). p la n t h e ig h t (c m ) 0 20 40 60 80 100 120 140 control sa si sa+si d cc a d a d b r o o t le n g th ( c m ) 0 10 20 30 40 control sa si sa+si a b ab ab ab ab b b brri dhan41 brri dhan49 a b 122 rima et al. fig. 2. effect of salicylic acid (sa) and silicon (si) on number of effective tiller. shoot-root fresh and dry weight shoot fresh weight showed a significant improvement by 8 and 39% due to the sole application of si, and co-application of sa and si in the tolerant rice var. brri dhan41 as compared with the untreated plants (figure 3a). however, the sensitive var. brri dhan49 showed a significant reduction in shoot fresh weight from sole sa application (13%) and combined application of sa and si (9%) when compared with control plants. however, no significant variation was observed in shoot fresh weight due to the application of si compared to the control plant. besides, coapplication of sa and si significantly enhanced shoot dry weight by 27% in brri dhan41; whereas, no significant variation was observed in both the rice varieties due to the sole application of sa and si (figure 3b). in case of root fresh weight, application of sa and si significantly reduced root fresh weight by 14 and 19% respectively, while combined application of sa and si remained statistically similar to the control plants of brri dhan41. likewise, brri dhan49 showed significant reduction due to the application of sole sa (28%) while other treatments (si and, combined sa and si) statistically similar to the control (figure 3c). besides, brri dhan41 significantly reduced root dry weight by 27 and 37% after sole application of sa, and combined application of sa and si, over control. similarly, in brri dhan49, root dry weight was significantly reduced by 28 and 29%, respectively when treated with sole sa and si. however, no significant difference of root dry weight was found from co-application of sa and si over control plant (figure 3d). several studies also revealed that si application enhances shoot fresh and dry weight by reducing the salt-induced negative impacts in rice and barley (farooq et al., 2015; flam-shepherd et al., 2018 and somaddar et al., 2022). however, mahdieh et al. (2015) and somaddar et al. (2022) observed that si application had no significant effects on the root fresh and dry weight of rice under salt stress, which is consistent with the present findings. n um be r of e ff ec ti ve ti ll er 0 5 10 15 20 25 30 control sa si sa+si a c a a a b b c brri dhan41 brri dhan49 effect of exogenous salicylic acid and silicon application on salinity tolerance of rice 123 fig. 3. effect of salicylic acid (sa) and silicon (si) on (a) shoot fresh weight, (b) shoot dry weight, (c) root fresh weight and (d) root dry weight. effect of sa and si on yield characters of rice under salt stress the data revealed that sole application of sa and co-application of sa and si significantly enhanced the number of grains per panicle by 64 and 29%, respectively in brri dhan41. while in brri dhan49 remarkably increased by 182 and 75% after treating with sole application of sa and si respectively, compared with the control plants (figure 4a). besides, the number of sterile spikelets was significantly reduced by 26% in brri dhan41 after sole application of sa compared with other treatments (figure 4b). notably in brri dhan49, the number of sterile spikelets remarkably reduced by 23, 38 and 49%, respectively after sole applications of sa, si, and co-application of sa and si as compared with the untreated plants under salinity (figure 4b). it also observed that exogenous application of si significantly increased thousand grain weight by 15% in brri dhan41, whereas, sole application of sa and co-application of sa and si showed statistically similar results as compared with control (figure 4c). in case of brri dhan49, no significant variation was observed in thousand grain weight under all the treatment combinations compared with the control plants under salinity (figure 4c). in addition, the number of grains per hill remarkably increased by 46% due to the application of sa in brri dhan41 over control plant (figure 4d). on the other hand, in brri dhan49, the number of grains per hill increased significantly by 277, 446 and 118% respectively, due to the sole s h o o t fr es h w ei g h t (g ) 0 100 200 300 control sa si sa+si a f g c d b a e s h o o t d ry w ei g h t (g ) 0 20 40 60 80 100 control sa si sa+si c b aba c c a a r o o t fr es h w ei g h t (g ) 0 20 40 60 80 100 control sa si sa+si ab cd bc ab a d d a r o o t d ry w ei g h t (g ) 0 10 20 30 40 control sa si sa+si cd de c ab a cde bc e brri dhan41 brri dhan49 a b c d 124 rima et al. applications of sa and si, and, co-application of sa and si under saline environment over control (figure 4d). fig. 4. effect of salicylic acid (sa) and silicon (si) on (a) number of grains panicle-1, (b) number of sterile spikelet panicle-1, (c) thousand grain weight and (d) number of grains hill-1. likewise, reports from several studies have also highlighted that 1 mm sa application significantly increased different yield attributes of rice such as the number of grains per panicle, thousand grain weight and grain yield under salt stress (jini and joseph, 2017). this finding corroborates with the present study. effect of exogenous sa and si on k+ and na+ accumulation in rice under salt stress result revealed that exogenous sa, si, and combined sa and si application significantly reduced na+ accumulation by 25, 34 and 20%, respectively in brri dhan41, and by 43, 40 and 23%, respectively in brri dhan49 (figure 5a). notably, the sole application of sa, and co-application of sa and si significantly increased k+ accumulation by 72 and 115%, respectively in brri dhan41. while, brri dhan49 showed a noticeable increase in k+ accumulation in shoot after application of sa, si, and co-application of sa and si, which are 29, 46 and 36%, respectively over control plants (figure 5b). importantly, the k+/na+ increased significantly in both brri dhan41 and brri dhan49 after sole application of sa (128 and 124%, respectively), si (42 and t h o u sa n d g ra in w ei g h t (g ) 0 5 10 15 20 25 control sa si sa+si ab b a ab ab ab ab ab n u m b er o f g ra in s p an ic le -1 0 20 40 60 80 100 control sa si sa+si c b a d c c b d n u m b er o f st er il e sp ik el et p an ic le -1 0 20 40 60 80 100 control sa si sa+si b a d c c d e d n u m b er o f g ra in s h il l-1 0 500 1000 1500 2000 control sa si sa+si b b a e cd c b de brri dhan41 brri dhan49 a b c d effect of exogenous salicylic acid and silicon application on salinity tolerance of rice 125 143%, respectively) and co-application of sa and si (168 and 76%, respectively) compared with untreated conditions (figure 5c). fig. 5. effect of salicylic acid (sa) and silicon (si) on accumulation of (a) na+, (b) k+ and (c) k+/na+ in rice under salt stress. it has been reported that the si application in rice reduced the leaf na+ while enhanced the levels of k+ and k+/ na+ (yan et al., 2020; somaddar et al., 2022). liang et al. (2007) also reported that si supplementation reduced the root na+ content under salt stress. conclusions the findings of the present study indicated that the application of si and sa have significant effect in the mitigation of salinity stress. the results suggested that the sensitive var. brri dhan49 showed highest plant height and number of effective tillers with the sole and combined application of sa and si. besides, different yield attributes such as number of grains per panicle and number of grains per hill showed a significant effect, and the number of sterile spikelets remarkably reduced when applied with sa and si, particularly in the salt-sensitive brri dhan49. the application of sa and si alone and, sa and si together significantly reduced na+ accumulation in rice leaf of both varieties; while the k+ content and k+/na+ increased in all the treatment combinations under salinity. however, the present findings showed new dimensions regarding the beneficial effects of sa and si solely, as well as combinedly on the growth and yield of rice under salinity. acknowledgement cordially thanks to professor dr. md. shariful islam, dept. of agricultural chemistry, patuakhali science and technology university for helping in the estimation of na+ and k+ in rice shoot. references abro, s.a., r. qureshi, f.m. soomro, a.a. mirbahar and g.s. jakhar. 2009. effects of silicon levels on growth and yield of wheat in silty loam soil. pak. j. bot. 41(3): 1385-1390. ahmed, m.f. and m.z. haider. 2014. impact of salinity on rice production in the south-west region of bangladesh. environ. sci. indian j. 9(4): 135-141. akram, n.a. and m. ashraf. 2011. pattern of accumulation of inorganic elements in sunflower (helianthus annuus l.) plants subjected to salt stress and exogenous application of 5aminolevulinic acid. pak. j. bot. 43(1): 521-530. n a+ ( m g g -1 d w ) 0 1 2 3 4 5 control sa si sa+si a c f ef de b d de k + ( m g g -1 d w ) 0 2 4 6 8 10 12 control sa si sa+si a c b d ab c d ab k + /n a+ 0 2 4 6 8 control sa si sa+si a b e ab bc d cd e a b c brri dhan41 brri dhan49 126 rima et al. ali, e.a. and a.m. mahmoud. 2013. effect of foliar spray by different salicylic acid and zinc concentrations on seed yield and yield components of mungbean in sandy soil. asian j. crop sci. 5(1): 33–40. dos santos, t.b., a.f. ribas, s.g.h. de souza, i.g.f. budzinski and d.s. domingues. 2022. physiological responses to drought, salinity, and heat stress in plants: a review. stresses, 2(1): 113-135. epstein, e. 1999. silicon. annu. rev. plant physiol. plant mol. biol. 50: 641–664. farooq, m.a., z.a. saqib and j. akhtar. 2015. silicon-mediated oxidative stress tolerance and genetic ariability in rice (oryza sativa l.) grown under combined stress of salinity and boron toxicity. turk. j. agric. for. 39: 718–729 flam-shepherd, r., w.q. huynh, d. coskun, a.m. hamam, d.t. britto and h.j. kronzucker. 2018. membrane fluxes, bypass flows, and sodium stress in rice: the influence of silicon. j. exp. bot. 69: 1679–1692. garg, n. and p. bhandari. 2015. silicon nutrition and mycorrhizal inoculations improve growth, nutrient status, k+/na+ ratio and yield of cicer arietinum l. genotypes under salinity stress. plant growth regul. 78(3): 371-387. hayat, q., s. hayat, m. irfan and a. ahmad. 2010. effect of exogenous salicylic acid under changing environment: a review. environ. expt. bot. 68(1): 14-25. husen, a., m. iqbal, s.s. sohrab and m.k.a. ansari. 2018. salicylic acid alleviates salinity-caused damage to foliar functions, plant growth and antioxidant system in ethiopian mustard (brassica carinata a. br.). agric. food secur. 7(1): 1-14. jini, d. and b. joseph. 2017. physiological mechanism of salicylic acid for alleviation of salt stress in rice. rice sci. 24(2): 97-108. khan, a., a.l. khan, s. muneer, y.h. kim, a. al-rawahi and a. al-harrasi. 2019. silicon and salinity: crosstalk in crop-mediated stress tolerance mechanisms. front. plant sci. 10: 1429. krishnamurthy, s.l., p.c. sharma, s.k. sharma, v. batra, v. kumar and l.v.s. rao. 2016. effect of salinity and use of stress indices of morphological and physiological traits at the seedling stage in rice. indian j. exp. biol. 54(12): 843-850. liang, x., s. fang, w. ji and d. zheng. 2015. the positive effects of silicon on rice seedlings under saline-alkali mixed stress. commun. soil sci. plant anal. 46: 2127–2138. liang, y., w. sun, y.g. zhu and p. christie. 2007. mechanisms of silicon mediated alleviation of abiotic stresses in higher plants: a review. environ. pollut. 147: 422–428 mahdieh, m., n. habibollahi, m.r. amirjani, m.h. abnosi and m. ghorbanpour. 2015. exogenous silicon nutrition ameliorates salt-induced stress by improving growth and efficiency of psii in oryza sativa l. cultivars. j. soil sci. plant nutr. 15(4): 1050–1060. nishimura, t., s. cha-um, m. takagaki and k. ohyama. 2011. survival percentage, photosynthetic abilities and growth characters of two indica rice (oryza sativa l. spp. indica) cultivars in response to is osmotic stress. span. j. agric. res. 9: 262–270. saqib, z.a., j. akhtar, m.a. ul-haq and i. ahmad. 2012. salt induced changes in leaf phenology of wheat plants are regulated by accumulation and distribution pattern of na+ ion. pak. j. agric. sci. 49: 141-148. shrivastava, p. and r. kumar. 2015. soil salinity: a serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation. saudi j. biol. sci. 22(2): 123-131. singh, p., v. kumar, j. sharma, s. saini, p. sharma, s. kumar, y. sinhmar, d. kumar and a. sharma. 2022. silicon supplementation alleviates the salinity stress in wheat plants by effect of exogenous salicylic acid and silicon application on salinity tolerance of rice 127 enhancing the plant water status, photosynthetic pigments, proline content and antioxidant enzyme activities. plants, 11(19): 2525. somaddar, u., h.c. dey, s.k. mim, u.k. sarker, m.r. uddin, n.u. ahmed, m.g. mostofa and g. saha. 2022. assessing silicon-mediated growth performances in contrasting rice cultivars under salt stress. plants. 11(14): 1831. wang, w., y. xu, t. chen, l. xing, k. xu, d. ji, c. chen and c. xie. 2019. regulatory mechanisms underlying the maintenance of homeostasis in pyropia haitanensis under hypersaline stress conditions. sci. total environ. 662: 168-179. xie, z., r. song, h. shao, f. song, h. xu and y. lu. 2015. silicon improves maize photosynthesis in saline-alkaline soils. sci. world j.: 245072. yan, g., x. fan, m. peng, c. yin, z. xiao and y. liang. 2020. silicon improves rice salinity resistance by alleviating ionic toxicity and osmotic constraint in an organ-specific pattern. front. plant sci. 11: 260. zhu, y., x. jiang, j. zhang, y. he, x. zhu, x. zhou, h. gong, j. yin and y. liu. 2020. silicon confers cucumber resistance to salinity stress through regulation of proline and cytokinins. plant physiol. biochem. 156: 209-220. zhu, z.j., g.q. wei, j. li, q.q. qian and j.q. yu. 2004. silicon alleviates salt stress and increases antioxidant enzymes activity in leaves of salt-stressed cucumber (cucumis sativus l.). plant sci. 167: 527–533. microsoft word 9. baj-476e bangladesh agron. j. 2024, 26(2): 67-76 growth, phenology and yield attributes of a white maize genotype sauwmopmdt273 under different planting configurations s. ahamed1, m. j. ullah1, m.s. islam1, m.h. mahmud2* and a. hossain3 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2project implementation unit-barc, national agricultural technology program-phase-ii project, farmgate, dhaka, bangladesh 3sub-station, bangladesh institute of nuclear agriculture, sunamganj, bangladesh *corresponding author, email: h.mahmud193@gmail.com (received: 20 february 2024, accepted: 02 may 2024) keywords: planting configurations, white maize, yield abstract a field experiment was carried out at the agronomy field of sher-e-bangla agricultural university, during the period from july to october, 2018 with fifteen planting configurations viz., t1 (40 cm × 15 cm), t2 (40 cm × 20 cm), t3 (40 cm × 25 cm), t4 (45 cm × 15 cm), t5 (45 cm × 20 cm), t6 (45 cm × 25 cm), t7 (50 cm × 15 cm), t8 (50 cm × 20 cm), t9 (50 cm × 25 cm), t10 (55 cm × 15 cm), t11 (55 cm × 20 cm), t12 (55 cm × 25 cm), t13 (60 cm × 15 cm), t14 (60 cm × 20 cm), and t15 (60 cm × 25 cm) to study the growth, phenology, yield attributes and yield of a white maize genotype sauwmopmdt273. the experiment was laid out in a randomized complete block design with three replications. regarding growth and yield parameters, the treatment 60 cm × 25 cm showed significantly the maximum plant height, tassel length and leaf area at silking, grain filling and at harvest. the highest area of an individual leaf 477.9, 879.3, and 496.3 cm2 as well as stem dry matter weight of 28.73, 21.35, and 27.40 g plant-1 respectively, below cob-node, at cob-node and above the cob-node during silking obtained from treatment 60 cm × 25 cm. the treatment 55 cm × 25 cm showed maximum biological yield (14.64 t ha−1) and 60 cm × 20 cm showed significantly the highest cob length (15.94 cm) and number of grains row−1 (20.00), but the highest number of grains cob−1 (231.50), 100 seed weight (29.99 g), grain weight cob−1 (59.81 g) were recorded from 55 cm × 25 cm. sparser configuration (60×20 cm) requiring less seed rate, this configuration may be followed. introduction maize (zea mays l.) is one of the most important cereal crops of the world. in bangladesh, the cultivation of maize has been gaining popularity in recent years because of its high productivity and diversified use (tajul et al., 2013). in bangladesh, it covers about 3.5 lac hectares of land producing 23 lac metric tons grains (baral, 2016). maize crop has been included as a major enterprise in the crop diversification and intensive cropping programs (zamir et al., 2011). the average yield of maize in bangladesh is not satisfactory. the national average yield is only 6.45 t ha−1, whereas, the newly released varieties have the potential to produce more than 8 t ha−1 (ais, 2015). yellow maize is preferred for feeding animals because it contains carotenoids; for this reason, white-maize production decreased from 50% in 1920 to 1% in 1970 (troyer, 1999). commercial quality requirements for white maize are quite strict for purity of the white color, large uniform size of kernels, high specific density, hard endosperm, and white cob (watson, 1988). the genetics of endosperm color has been summarized by coe et al. (1988), who exposed the complex genetic interactions of the numerous factors involved in the determination of endosperm color and other traits, such as chlorophyll synthesis or endosperm morphology. plant spacing is an important factor, which plays a significant role on growth, development and yield of maize. less plant population and poor nutrient management practices are the major yield reducing factors in maize (dawadi and sah, 2012). the broadcasting method produced the most effective spatial arrangements. it generally gave lower yields than sowing in rows (krezel and sobkowicz, 1996). 68 ahamed et al. maize differs in its responses to plant density (luque et al., 2006). closer row spacing leading to overcrowding, enhanced inter-plant competition for incident photosynthetic photon flux density and soil rhizosphere resource, resulting reduced yield per plant because of its influence on hormonally mediated apical dominance, exaggerated barrenness, and there by finally decreases the number of ears plant-1 and kernels ear−1 (sangoi, 2001). adjustment of proper plant spacing in the maize field is important to ensure maximum utilization of solar energy by the crop and reduce evaporation of soil moisture (fao, 2012). this experiment was designed to evaluate growth, phenology and yield attributes of the white maize genotype sauwmopmdt273 under different planting configurations. materials and methods the experiment was conducted at the experimental field of sher-e-bangla agricultural university, dhaka under the agro-ecological zone of modhupur tract, aez-28 during the kharif-ii season from july to october, 2018. the experimental area is under the sub-tropical climate that is characterized by high temperature, high humidity, and heavy rainfall with occasional gusty winds in kharif season (april-september) and less rainfall associated with moderately low temperature during the rabi season (october-march). the experiment was laid out in a randomized complete block design with three replications. the treatments (spacing) were as follows: t1= 40 cm × 15 cm, t2= 40 cm × 20 cm, t3= 40 cm × 25 cm, t4= 45 cm × 15 cm, t5= 45 cm × 20 cm, t6= 45 cm × 25 cm, t7= 50 cm × 15 cm, t8= 50 cm × 20 cm, t9= 50 cm × 25 cm, t10= 55 cm × 15 cm, t11= 55 cm × 20 cm, t12= 55 cm × 25 cm, t13= 60 cm × 15 cm, t14= 60 cm × 20 cm, t15= 60 cm × 25 cm. in this research work, white maize genotype sauwmopmdt273 variety was used as plant materials and the seeds were collected from sau, dhaka. the plot selected for the experiment was prepared on the first week of july 2018. weeds and stubble were removed and finally obtained a desirable field. fertilizers and manure were applied for the cultivation of crops as recommended by bari, 2014. the baby corn seeds were sown in lines maintaining plant to plant and row to row distance as per treatments having 2 seeds hole−1 under direct sowing in the plot. all intercultural operations like gap filling, weeding, plant protection, irrigation and drainage were taken properly. the cobs of five randomly selected plants of each plot were separately harvested for recording data on yield attributes and other parameters.the plant height, tassel length plant−1, cob length and breadth as recorded in centimeters (cm) at the time of silking, 15 days of silking and at harvest. leaf area and dry matter content plant−1 were measured at three stages viz., at silking, 15 days after silking and at harvest and this data was taken from three part of the plant (lower leaves, cob leaves and upper leaves) separately. number of grains row−1, number of grains cob−1, weight of 100 seeds (g), grain weight cob−1 (g), shell weight cob−1 (g), chaff weight cob−1 (g), grain yield (t ha−1) and stover yield (t ha−1) was counted. cob (dehusked) and stover obtained from each unit plot were sun-dried and weighed carefully. the harvest index was calculated with the following formula: harvest index (%) = grain yield biological yield × 100 the data were analyzed, and the means were separated by lsd at 5% level of significance using the statistical computer package program mstat-c. results and discussion plant height significant influence was recorded on plant height of maize at different growth stages as affected by different planting configurations (table 1). the treatment 60 cm × 25 cm showed highest plant height at all three stages (217.00, 220.30 and 220.70 cm at silking time, 15 days after silking time and at harvest, respectively) whereas the shortest plant was observed (190.30, 184.30 and 175.50 cm at silking time, 15 days after silking time and at harvest, respectively) from 40 cm × 15 cm. similar result was found by fromme et al. (2019). but zeleke et al. (2018) also found that plant height, significantly increased with increasing planting density from 44,444 to 88,888 plants ha−1. growth, phenology and yield attributes of maize under different planting configurations 69 tassel length significant influence was recorded on tassel length of maize at different growth stages as affected by different planting configurations (table 1). the treatment 60 cm × 25 cm showed maximum tassel length of maize at all three stages (48.00, 52.80 and 39.77 cm at silking time, 15 days after silking time and at harvest, respectively) whereas the minimum tassel length was observed (33.00, 26.67 and 27.98 cm at silking time, 15 days after silking time and at harvest, respectively) from the treatment 40 cm × 15 cm. the highest tassel length from 60 cm × 25 cm which might be due to cause of higher nutrients light and air availability during the cropping period. table 1. plant height and tassel length of maize as influenced by different planting configurations treatments plant height (cm) tassel length (cm) at silking at 15 days of silking at harvest at silking at 15 days of silking at harvest t1 190.3 h 184.3 g 175.5 h 33.00 f 26.67 f 27.98 j t2 197.7 g 200.7 c 190.6 e 37.67 e 32.10 e 28.93 j t3 200.3 f 206. b 184.1 f 34.33 f 37.70 d 31.30 hi t4 209.7 c 209.3 b 176.5 gh 44.00 c 39.17 cd 30.50 i t5 197.0 g 200.3 c 179.3 g 41.33 d 37.77 d 34.38 de t6 210.3 c 194.3 ef 179.3 g 46.00 b 37.17 d 31.02 hi t7 211.3 c 196.3 e 194.2 d 44.00 bc 37.30 d 33.37 ef t8 204.7 de 197.0 de 201.2 c 43.33 cd 37.13 d 32.60 fg t9 206.7 d 201.3 c 177.0 gh 38.00 e 40.13 c 36.33 c t10 201.7 f 195.0 ef 206.5 b 37.00 e 38.20 cd 31.67 gh t11 214.3 b 208.7 b 186.3 f 44.00 bc 38.17 cd 35.23 d t12 205.0 de 217.7 a 204.2 bc 44.00 bc 37.97 cd 37.28 c t13 196.0 g 192.7 f 204.0 bc 39.00 e 44.33 b 36.52 c t14 202.7 ef 199.7 cd 194.0 d 43.33 cd 44.63 b 38.72 b t15 217.0 a 220.3 a 220.7 a 48.00 a 52.80 a 39.77 a lsd0.05 2.464 3.092 3.128 1.948 2.06 1.048 cv (%) 8.59 6.97 9.12 9.66 7.55 6.53 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability t1 = 40 cm × 15 cm, t2 = 40 cm × 20 cm, t3 = 40 cm × 25 cm, t4 = 45 cm × 15 cm, t5 = 45 cm × 20 cm, t6 = 45 cm × 25 cm, t7 = 50 cm × 15 cm, t8 = 50 cm × 20 cm, t9 = 50 cm × 25 cm, t10 = 55 cm × 15 cm, t11 = 55 cm × 20 cm, t12 = 55 cm × 25 cm, t13 = 60 cm × 15 cm, t14 = 60 cm × 20 cm, t15 = 60 cm × 25 cm leaf area at silking time significant influence was recorded on leaf area of maize at silking time as affected by different planting configurations (table 2). at all three portions of maize plant, the maximum leaf area at silking time (477.90, 879.30 and 496.30 cm2 leaf−1 at leaves below cobnode, leaf at cob-node and leaves above cob-node, respectively) was found from the treatment 60 cm × 25 cm followed by 60 cm × 20 cm whereas the minimum leaf area at silking time (302.50, 595.50 and 262.90 cm2 leaf−1 at leaves below cobnode, leaf at cob-node and leaves above cob-node, respectively) was found from the treatment 40 cm × 15 cm. leaf area at 15 days of silking time significant influence was recorded on leaf area of maize at 15 days after silking time as affected by different planting configurations (table 2). at all three portion of maize plant, the maximum leaf area at 15 days after silking time (511.60, 756.40 and 381.00 cm2 leaf−1 at leaves below cobnode, leaf at cobnode and leaves above cob-node, respectively) was found from the treatment 60 cm × 25 cm followed by treatment 60 cm × 20 cm whereas the minimum leaf area at 15 days after silking time (247.70, 562.80 and 256.60 cm2 leaf−1 at leaves below cobnode, leaf at cob-node and leaves above cob-node, respectively) was found from the treatment 40 cm × 15 cm. 70 ahamed et al. table 2. leaf area (cm2 leaf−1) of maize at silking, 15 days of silking time and harvest as influenced by different planting configurations treatments at silking at 15 days of silking time at harvest leaves below cobnode leaf at cob-node leaves above cobnode leaves below cob node leaf at cob-node leaves above cob-node leaves below cobnode leaf at cob-node leaves above cobnode t1 302.5 k 595.5 k 262.9 l 247.7 l 562.8 k 256.6 j 145.7 k 365.4 j 211.1 k t2 350.0 j 621.4 i 316.4 ij 281.1k 591.6 i 274.5 i 183.9 h 438.6 i 262.7ef t3 356.3 i 662.9 g 293.3 k 297.8 j 633.5 f 291.8h 170.8 j 446.1 h 246.3 h t4 364.9 h 681.1 e 409.3 ef 313.9 i 617.6 g 273.3 i 181.8hi 446.9 h 253.8 g t5 373.4 g 659.0 g 353.8 g 326.0h 562.6 k 289.4h 175.2 ij 445.5 h 259.6 fg t6 306.5 k 676.5ef 428.3 d 369.8g 579.5 j 299.1g 233.9 d 513.0 d 267.7 e t7 406.2 e 614.6 j 311.0 ij 380.9 f 674.2 e 291.0h 201.6 g 432.7 i 236.7 i t8 370.0 gh 627.5 i 309.9 j 367.3g 715.2 d 311.2 f 172.7 j 445.9 h 224.0 j t9 346.6 j 613.2 j 331.3 h 298.4 j 720.3cd 368.8c 200.6g 494.8ef 290.1 d t10 389.5 f 646.8 h 318.8 i 283.2k 668.6 e 350.5d 230.1de 474.5 g 294.6 d t11 375.7 g 671.5 f 404.0 f 393.1e 605.3 h 321.4e 226.4 e 490.4 f 288.7 d t12 442.4 d 734.0 d 414.0 e 414.1d 749.8ab 362.3c 209.1 f 497.5 e 315.3 c t13 452.1 c 747.0 c 444.6 c 441.6c 726.5 c 372.9b 256.3 c 523.2 c 318.5 c t14 470.3 b 771.3 b 464.6 b 467.6b 745.1 b 355.1d 284.1 b 549.1 b 344.3 b t15 477.9 a 879.3 a 496.3 a 511.6a 756.4 a 381.0a 302.1a 615.6 a 389.0 a lsd0.05 5.824 6.404 7.529 7.161 6.926 6.754 6.964 6.688 6.838 cv (%) 10.17 12.24 9.00 8.79 10.17 13.20 7.14 11.86 12.57 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability t1 = 40 cm × 15 cm, t2 = 40 cm × 20 cm, t3 = 40 cm × 25 cm, t4 = 45 cm × 15 cm, t5 = 45 cm × 20 cm, t6 = 45 cm × 25 cm, t7 = 50 cm × 15 cm, t8 = 50 cm × 20 cm, t9 = 50 cm × 25 cm, t10 = 55 cm × 15 cm, t11 = 55 cm × 20 cm, t12 = 55 cm × 25 cm, t13 = 60 cm × 15 cm, t14 = 60 cm × 20 cm, t15 = 60 cm × 25 cm leaf area at harvest significant influence was recorded on leaf area of maize at harvest as affected by different planting configurations (table 2). at all three portion of maize plant, the maximum leaf area at harvest (302.10, 615.60 and 389.00 cm2 leaf−1 at leaves below cobnode, leaf at cob-node and leaves above cobnode, respectively) was found from the treatment 60 cm × 25 cm followed by treatment 60 cm × 20 cm whereas the minimum leaf area at harvest (147.70, 365.40 and 211.10 cm2 leaf−1 at leaves below cob node, leaf at cob-node and leaves above cob-node, respectively) was found from the treatment 40 cm × 15 cm. similar result was also observed by enujeke (2013) who found higher leaf area per plant with 75 cm × 35 cm compared to 75 cm × 15 cm plant spacing. dry matter content at silking time significant influence was recorded on dry matter content of maize at silking time at different portion of plant as affected by different planting configurations (table 3). at all three portions of maize plant, the maximum dry matter content at silking time (31.32, 29.17 and 27.25 g plant−1 at below cobsnode, at cob-node and above cob-node, respectively) was found from the treatment 55 cm × 25 cm whereas the minimum dry matter content at silking time (16.85, 11.95 and 15.46 g plant−1 at below cobsnode, at cob-node and above cob-node, respectively) was found from the treatment 40 cm × 15 cm. dry matter content at 15 days after silking significant influence was recorded on dry matter content of maize at 15 days after silking as affected by different planting configurations (table 3). at all three portions of maize plant, the maximum dry matter content at 15 days after silking time (34.47, 73.54 and 28.00 g plant−1 at below cobs-node, at cob-node and above cob-node, respectively) was found from the treatment 55 cm × 25 cm whereas the minimum dry matter content at 15 days after silking time (19.45, 28.99 and 17.06 g plant−1 at below cobs-node, at cob-node and above cob-node, respectively) was found from the treatment 40 cm × 15 cm. dry matter content at harvest growth, phenology and yield attributes of maize under different planting configurations 71 significant influence was recorded on dry matter content of maize at harvest as affected by different planting configurations (table 3). table 3. stem dry matter content of maize at silking time, 15 days after silking and harvest as influenced by different planting configurations treatment at silking time at 15 days after silking at harvest below cobs-node at cobnode above cob-node below cobs-node at cobnode above cob-node below cobs-node at cobnode above cob-node t1 16.85 f 11.95 h 15.46 h 19.45 j 28.99 k 17.06h 15.76 h 33.17g 10.62g t2 22.80de 15.81 g 18.01fg 20.90ij 32.80 j 17.63h 22.73de 46.73b 12.97cd t3 22.12de 12.51 h 17.38 g 24.59fg 44.09g 15.52 i 21.24 f 37.90ef 12.17def t4 21.52 e 19.88ef 22.38 c 26.91de 33.33ij 17.71gh 17.11 h 37.34 f 12.78 cd t5 23.28de 24.39bc 18.36fg 23.32gh 34.28 i 19.38ef 20.50 f 35.31fg 13.56 bc t6 22.04de 16.01 g 25.51 b 32.73 a 37.73h 21.65 d 18.61 g 40.92de 12.65cde t7 24.25cde 23.81 c 18.12fg 30.61 b 47.50f 25.58 b 20.58 f 34.73fg 14.00 b t8 24.45cd 19.75 f 19.44ef 26.13ef 50.57de 19.03fg 21.00 f 36.38 f 13.43 bc t9 26.66bc 22.25 d 20.66de 28.41cd 49.33 e 23.54 c 23.77cde 37.41 f 11.64efg t10 28.29 b 21.59 d 21.93cd 24.93fg 51.23 d 18.28fgh 22.64 e 43.38cd 12.59cde t11 23.05 de 12.60 h 22.37 c 29.67bc 52.87 c 18.11fgh 24.03 cd 46.48bc 11.20 fg t12 31.32 a 29.17 a 27.25 a 34.47 a 73.54 a 28.00 a 28.07 a 56.21 a 15.10 a t13 22.73 de 18.89 f 18.05fg 22.15hi 49.71 e 19.35 ef 24.38 c 49.59 b 14.07 b t14 27.61 b 21.35de 19.33ef 29.45bc 50.33de 20.65 de 26.00 b 54.81 a 14.33 ab t15 28.73 ab 25.91 b 27.40 a 34.27 a 64.46 b 27.97 a 28.30 a 54.45 a 14.24 ab lsd0.05 0.52 0.29 0.28 0.35 0.27 0.26 0.26 0.60 0.19 cv (%) 8.89 7.47 6.60 9.80 11.60 10.89 12.05 9.20 7.51 in a column means having similar letters arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability t1 = 40 cm × 15 cm, t2 = 40 cm × 20 cm, t3 = 40 cm × 25 cm, t4 = 45 cm × 15 cm, t5 = 45 cm × 20 cm, t6 = 45 cm × 25 cm, t7 = 50 cm × 15 cm, t8 = 50 cm × 20 cm, t9 = 50 cm × 25 cm, t10 = 55 cm × 15 cm, t11 = 55 cm × 20 cm, t12 = 55 cm × 25 cm, t13 = 60 cm × 15cm, t14 = 60 cm × 20 cm, t15 = 60 cm × 25 cm at all three portion of maize plant, the maximum dry matter content at harvest (28.07, 56.21 and 15.10 g plant−1 at below cobs-node, at cob-node and above cob-node, respectively) was found from the treatment 55 cm × 25 cm whereas the minimum dry matter content at harvest (15.76, 33.17 and 10.62 g plant−1 at below cobs-node, at cob-node and above cob-node, respectively) was found from the treatment 40 cm × 15 cm. ibeawuchi and matthews-njoku (2008) achieved highest dry matter with the plant spacing of 25 cm × 75 cm and found that higher nutrient efficiency showed higher dry matter accumulation in plants. under the present study higher plant spacing 55 cm × 25 cm showed higher dry matter content compared to others which was supported by the finding of ibeawuchi and matthewsnjoku (2008). cob length significant influence was recorded on cob length of maize as affected by different planting configurations (table 4). table 4. yield contributing parameters of maize as influenced by different planting configurations treatment yield contributing parameters cob length (cm) cob breadth (cm) number of rows cob−1 number of grains row−1 number of grains cob−1 100-grain weight (g) t1 9.19 g 9.62 f 8.22 i 6.89 j 61.21 k 23.38 e t2 9.58 g 10.03 ef 8.83 hi 10.56 hi 93.58 j 24.04 e t3 9.31 g 10.10 ef 8.67 hi 9.66 i 86.86 j 25.46 d t4 10.78 f 10.69 e 9.22 gh 11.33 h 107.40 i 27.77 c t5 11.80 ef 11.52 d 10.00 f 14.00 f 140.20 g 28.29 bc t6 11.05 f 12.22 c 11.67 b 14.11 ef 164.10 e 25.73 d t7 11.51 ef 10.68 e 10.67 de 15.55 d 165.60 e 27.38 c 72 ahamed et al. treatment yield contributing parameters cob length (cm) cob breadth (cm) number of rows cob−1 number of grains row−1 number of grains cob−1 100-grain weight (g) t8 13.13 cd 12.08 cd 11.11 bcd 15.33 de 170.30 e 27.55 c t9 13.51 bcd 12.94 ab 11.33 bc 12.67 g 140.30 g 28.43 bc t10 12.35 de 12.54 abc 9.22 gh 13.11 fg 121.60 h 29.95 a t11 13.49 bcd 12.27 bc 9.66 fg 15.56 d 154.10 f 28.08 bc t12 13.77 bc 13.06 a 12.33 a 18.67 b 231.50 a 29.99 a t13 14.39 b 12.46 abc 11.00 cd 17.34 c 189.50 c 27.96 bc t14 15.94 a 12.01 cd 10.78 cde 20.00 a 218.50 b 29.51 a t15 14.28 bc 12.13 cd 10.22 ef 17.44 bc 181.20 d 28.94 ab lsd0.05 0.23 0.13 0.12 0.24 1.34 0.20 cv (%) 7.76 8.21 13.34 7.07 12.72 8.85 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability t1 = 40 cm × 15 cm, t2 = 40 cm × 20 cm, t3 = 40 cm × 25 cm, t4 = 45 cm × 15 cm, t5 = 45 cm × 20 cm, t6 = 45 cm × 25 cm, t7 = 50 cm × 15 cm, t8 = 50 cm × 20 cm, t9 = 50 cm × 25 cm, t10 = 55 cm × 15 cm, t11 = 55 cm × 20 cm, t12 = 55 cm × 25 cm, t13 = 60 cm × 15cm, t14 = 60 cm × 20 cm, t15 = 60 cm × 25 cm the highest cob length (15.94 cm) was recorded from the treatment 60 cm × 20 cm which was significantly different from all other treatments followed by the treatment 60 cm × 15 cm. the lowest cob length (9.19 cm) was found from the treatment 40 cm × 15 cm which was statistically identical with the treatment 40 cm × 20 cm and 40 cm × 25 cm. fanadzo et al. (2010) found similar result with the present study and observed that higher cob length per plant was found from higher plant spacing. ramchandrappa et al. (2004), kunjir (2007), bairagi et al. (2015) and chamroy et al. (2017) also found similar result with the present study. cob breadth significant influence was recorded on cob breadth of maize as affected by different planting configurations (table 4). the highest cob breadth (13.06 cm) was recorded from the treatment 55 cm × 25 cm which was statistically similar with the treatment 50 cm × 25 cm, 55 cm × 15 cm and 60 cm × 15 cm. on the other hand, the lowest cob breadth (9.62 cm) was found from the treatment 40 cm × 15 cm. under the present study, the highest cob breadth (13.06 cm) from 55 cm × 25 cm which might be due to cause of higher nutrient uptake from lower plant population due to less competition of nutrients. number of rows cob-1 significant influence was recorded on number of rows cob−1 of maize as affected by different planting configurations (table 4). the highest number of rows cob−1 (12.33) was recorded from the treatment 55 cm × 25 cm which was significantly different from all other treatments followed by 45 cm × 25 cm, 50 cm × 25 cm and 55 cm × 15 cm. the lowest number of rows cob−1 (8.22) was found from the treatment 40 cm × 15 cm which was statistically similar with the treatment 40 cm × 20 cm and 40 cm × 25 cm. rahman et al. (2016) supported the present study who reported that number of rows cob−1 per plant basis was achieved with wider row spacing compared to lower plant spacing. similar result was also observed by kunjir (2007). number of grains row−1 significant influence was recorded on number of grains row−1 of maize as affected by different planting configurations (table 4). the highest number of grains row−1 (20.00) was recorded from the treatment 60 cm × 20 cm which was significantly different from all other treatments followed by 55 cm × 25 cm and 60 cm × 25 cm. the lowest number of grains row−1 (6.89) was found from the treatment 40 cm × 15 cm which was significantly different from all other treatments. similar result was also observed by rahman et al. (2016) and kunjir (2007). number of grains cob−1 growth, phenology and yield attributes of maize under different planting configurations 73 significant influence was recorded on number of grains cob−1 of maize as affected by different planting configurations (table 4). the highest number of grains cob−1 (231.50) was recorded from the treatment 55 cm × 25 cm which was significantly different from all other treatments followed by 60 cm × 20 cm. the lowest number of grains cob−1 (61.21) was found from the treatment 40 cm × 15 cm which was significantly different from all other treatments. the result obtained from the present study was similar with the findings of rahman et al. (2016), kunjir (2007) and bairagi et al. (2015). weight of 100-seeds significant influence was recorded on 100-seed weight of maize as affected by different planting configurations (table 4). the highest 100-seed weight (29.99 g) was recorded from the treatment 55 cm × 25 cm which was statistically similar with the treatment 55 cm × 15 cm, 60 cm × 20 cm and 60 cm × 25 cm. the lowest 100-seed weight (23.38 g) was found from the treatment 40 cm × 15 cm which was statistically identical with the treatment 40 cm × 20 cm. similar result was also observed by shafi et al. (2012) who found higher 100-seed weight with higher plant spacing. kunjir (2007) also found 1000-grains weight increased significantly with wider spacing 75 cm × 20 cm as compared to narrower spacing 45 cm × 20 cm and 60 cm × 20 cm. rahman et al. (2016) also found similar result with the present study. grain weight cob−1 significant influence was recorded on grain weight cob−1 of maize as affected by different planting configurations (table 5). the highest grain weight cob−1 (59.81 g) was recorded from the treatment 55 cm × 25 cm which was statistically identical with the treatment 60 cm × 25 cm. the lowest grain weight cob−1 (17.42 g) was found from the treatment 40 cm × 15 cm which was significantly different from all other treatments. the treatment 40 cm × 20 cm, 40 cm × 25 cm and 45 cm × 15 cm also showed lower result on grain weight cob−1 which was closer to 40 cm × 15 cm but significantly different from them. similar result was also observed by kunjir (2007) who observed weight of grains per cob, increased significantly with wider spacing 75 cm × 20 cm as compared to narrower spacing 45 cm × 20 cm and 60 cm × 20 cm. similar result was also observed by rahman et al. (2016). shell weight cob−1 significant influence was recorded on shell weight cob−1 of maize as affected by different planting configurations (table 5). the highest shell weight cob−1 (15.33 g) was recorded from the treatment 60 cm × 20 cm which was statistically similar with the treatment 55 cm × 25 cm whereas the lowest shell weight cob−1 (7.76 g) was found from the treatment 40 cm × 15 cm which was statistically similar with the treatment 40 cm × 20 cm, 45 cm × 15 cm and 50 cm × 15 cm. chaff weight cob−1 significant influence was recorded on chaff weight cob−1 of maize as affected by different planting configurations (table 5). the highest chaff weight cob−1 (8.24 g) was recorded from the treatment 55 cm × 25 cm which was statistically identical with the treatment 60 cm × 20 cm and 60 cm × 25 cm and 60 cm × 15 cm. the lowest chaff weight cob−1 (4.00 g) was found from the treatment 40 cm × 15 cm which was statistically similar with the treatment but 40 cm × 20 cm, 40 cm × 25 cm and 45 cm × 15 cm also showed closer result on chaff weight cob−1 compared to 40 cm × 15 cm. grain yield ha−1 significant influence was recorded on grain yield ha−1 of maize as affected by different planting configurations (table 5). the highest grain yield (4.77 t ha−1) was recorded from the treatment 55 cm × 20 cm which was statistically identical with the treatment 45 cm × 20 cm, 50 cm × 15 cm, 60 cm × 15 cm and 60 cm × 20 cm followed by 55 cm × 15 cm. the lowest grain yield ha−1 (2.11 t ha−1) was found from the treatment 40 cm × 25 cm which was significantly different from all other treatments. the treatment 40 cm × 15 cm and 50 cm × 25 cm also showed lower result on which was closer to 40 cm × 25 cm but significantly different from them. similar result was also observed by shafi et al. (2012), rahman et al. 74 ahamed et al. (2016), hasan et al. (2018) and stephanus et al. (2018) who observed grain yield ha−1 significantly increased with increasing planting density to a certain level. stover yield ha−1 significant influence was recorded on stover yield ha−1 of maize as affected by different planting configurations (table 5). the highest stover yield (10.60 t ha−1) was recorded from the treatment 40 cm × 20 cm which was statistically identical with the treatment 40 cm × 15 cm, 45 cm × 15 cm and 60 cm × 15 cm followed by 50 cm × 15 cm and 55 cm × 15 cm, 55 cm × 15 cm. the lowest stover yield ha−1 (5.66 t ha−1) was found from the treatment 50 cm × 25 cm which was significantly different from all other treatments. shafi et al. (2012) and rahman et al. (2016) also found similar result with the present study. biological yield ha−1 significant influence was recorded on biological yield ha−1 of maize as affected by different planting configurations (table 4). the highest biological yield (14.48 t ha−1) was recorded from the treatment 60 cm × 15 cm which was statistically similar with the treatment 40 cm × 20 cm, 45 cm × 15 cm and 50 cm × 15 cm. the lowest biological yield ha−1 (8.68 t ha−1) was found from the treatment 50 cm × 25 cm which was significantly different from all other treatments. the treatment 40 cm × 25 cm and 45 cm × 25 cm also showed lower result on biological yield ha−1 which was closer to 50 cm × 25 cm but significantly different stephanus et al. (2018) and rahman et al. (2016) also found similar result with this study. harvest index harvest index influenced significantly by different planting configurations (table 5). the highest harvest index (40.52%) was recorded from the treatment 55 cm × 20 cm which was significantly different from all other treatments followed by 45 cm × 20 cm, 50 cm × 20 cm, 55 cm × 20 cm and 60 cm × 25 cm. the lowest harvest index (22.63%) was found from the treatment 40 cm × 15 cm which was significantly same with the treatments 40 cm × 25 cm. the treatment 40 cm × 20 cm and 60 cm × 15 cm also showed lower result on harvest index which was closer to 40 cm × 15 cm but significantly different. similar result was also observed by stephanus et al. (2018) and hasan et al. (2018). table 5. yield parameters of maize as influenced by different planting configurations treatment grain weight cob−1 (g) shell weight cob−1 (g) chaff weight cob−1 (g) grain yield (t ha−1) stover yield (t ha−1) biological yield (t ha−1) harvest index (%) t1 17.42 k 7.75 i 4.00 g 2.99 f 10.21 a 13.19 b 22.63 k t2 26.12 i 8.32 hi 5.33 f 3.36 e 10.60 a 13.96 ab 24.06 j t3 21.09 j 8.81 h 5.13 f 2.11 g 7.13 e 9.24 i 22.82 k t4 25.53 i 8.53 hi 5.34 f 3.89 c 10.24 a 14.13 ab 27.52 i t5 40.87 e 9.69 g 6.81 c 4.67 a 7.93 cd 12.60 cd 37.07 b t6 40.32 ef 9.96 g 6.11 e 3.58 d 6.42 fg 10.00 h 35.84 cd t7 35.26 h 8.51 hi 6.24 e 4.70 a 9.24 b 13.94 ab 33.72 f t8 41.94 e 12.19 ef 6.91 c 4.19 b 7.08 e 11.28 f 37.20 b t9 38.81 fg 12.70 de 6.36 de 3.02 f 5.66 h 8.68 j 34.77 e t10 37.99 g 11.70 f 6.70 cd 4.34 b 8.98 b 13.33 b 32.58 g t11 55.67 b 13.20 cd 7.67 b 4.77 a 7.00 e 11.78 e 40.52 a t12 59.81 a 14.57 ab 8.24 a 3.99 c 6.63 f 10.61 g 37.57 b t13 40.42 e 12.82 de 8.05 ab 4.62 a 10.06 a 14.68 a 31.47 h t14 55.47 b 15.33 a 8.19 a 4.75 a 8.15 c 12.91 c 36.83 bc t15 58.32 a 13.81 bc 8.13 a 3.89 c 6.47 fg 10.35 gh 37.55 b lsd0.05 0.32 0.16 0.08 0.04 0.40 0.49 1.03 cv (%) 12.83 8.39 11.03 11.92 12.32 12.24 11.14 in a column means having similar letters) arc statistically identical and those having dissimilar letter(s) differ significantly as per 0.05 level of probability growth, phenology and yield attributes of maize under different planting configurations 75 t1 = 40 cm × 15 cm, t2 = 40 cm × 20 cm, t3 = 40 cm × 25 cm, t4 = 45 cm × 15 cm, t5 = 45 cm × 20 cm, t6 = 45 cm × 25 cm, t7 = 50 cm × 15 cm, t8 = 50 cm × 20 cm, t9 = 50 cm × 25 cm, t10 = 55 cm × 15 cm, t11 = 55 cm × 20 cm, t12 = 55 cm × 25 cm, t13 = 60 cm × 15cm, t14 = 60 cm × 20 cm, t15 = 60 cm × 25 cm conclusion considering the above results, it may be concluded that higher planting density (lower number of plant population per unit area) showed better performance in terms of per plant basis compared to lower plant density (higher number of plant population per unit area) but in case of per ha yield, lower planting density showed better result compared to higher planting density. with this respect, the highest grain weight cob−1 (59.81 g) was found from the treatment 55 cm × 25 cm whereas the highest grain yield (4.77 t ha−1) was recorded from the treatment 55 cm × 20 cm. from the above findings, it can be concluded that the spacing 55 cm × 20 cm showed highest grain yield (4.77 t ha−1) and harvest index (40.52%). so, the plant spacing 55 cm × 20 cm could be considered for higher grain yield as compared to other planting configurations. references ais, 2015. agriculture information service. area, production and yield of different crops. agriculture information service. khamarbari, dhaka. pp. 14. bairagi, s., m.k. pandit, p. sidhya, s. adhikary and a.v.v. koundinya. 2015. impacts of date of planting and crop geometry on growth and yield of baby corn (zea mays var. rugosa). j. crop weed. 11(2):127-131. baral, b. 2016. agricultural market information system (amis) in bangladesh. asia and pacific commission on agricultural statistics. twenty-sixth session on asia and pacific commission on agriculture statistics, 1519 february, thimphu, bhutan. bari. 2014. bangladesh agricultural research institute. krishi projukti hat boi, bangladesh agricultural research institute. pp. 54 chamroy, t., v.s. kale, p.k. nagre, v.n. dod, s.s. wanjari and s.w. jahagirdar. 2017. growth and yield response of baby corn (zea mays l.) to sowing time and crop geometry. chem. sci. rev. lett. 2017. 6(22): 978-981. coe, e.h., m.g. neuffer and d.a. hoisington. 1988. the genetics of maize. in: g.f. sprague and j.w. dudley (ed.). maize and maize improvement, 3rd ed. asa, cssa, sssa, madison, wi. dawadi, d.r. and s.k. sah. 2012. growth and yield of hybrid maize (zea mays l.) in relation to planting density and nitrogen levels during winter season in nepal. tropic. agric. res. 23(3): 218-227. enujeke, e.c. 2013. effects of variety and spacing on growth characters of hybrid maize. asian j. agric. rural dev. 3(5): 296-310. fanadzo, m., c. chiduza and p.n.s. mnkeni. 2010. effect of inter-row spacing and plant population on weed dynamics and maize (zea mays l.) yield at zanyokwe irrigation scheme, eastern cape, south africa. african j. agric. res. 5(7): 518-523. fao. 2012. food and agriculture organization. production report of agricultural crop. http://faostat.fao.org/site/ 339/default.aspx fromme, d.d., t.a. spivey and w.j. grichar. 2019. agronomic response of corn (zea mays l.) hybrids to plant populations. int. j. agron. 2019(1): 1-8. hasan, m.r., m.r. rahman and a.k. hasan. 2018. effect of variety and spacing on the yield performance of maize (zea mays l.) in old brahmaputra floodplain area of bangladesh. agric. environ. sci. 3(3): 270-274. ibeawuchi, i.i. and matthews-njoku. 2008. plant spacing, dry matter accumulation and yield of local and improved maize cultivars. j. american sci. 4(1): 11-20. krezel, r. and p. sobkowicz. 1996. the effect of sowing rates and methods on winter triticale grown on light soil. roczniki nauk rolniczych. seria a, produkcja roślinna. 111(3&4): 69-78. kunjir, s.s., s.a. chavan, s.b. bhagat and n.b. zende. 2007. effect of planting geometry, nitrogen levels and micronutrients on the growth and yield of sweet corn. crop prot. prod. 2(3): 25-27. luque, s.f., a.g. cirilo and m.e. otegui. 2006. genetic gains in grain yield and related physiological attributes in argentine maize hybrids. field crop res. 95: 383-397. rahman, m.m., s.k. paul and m.m. rahman. 2016. effects of spacing and nitrogen levels on yield and yield contributing characters of maize. j. bangladesh agril. univ. 14(1): 43–48. ramachandrappa, b.k., h.v. nanjappa and h.k. shivakumar. 2004. yield and quality of baby corn (zea mays l.) as influenced by spacing and fertilizer levels. acta-agronomica-hungarica. 52(3): 237-243. 76 ahamed et al. sangoi, l. 2001. understanding plant density effects on maize growth and development: an important issue to maximize grain yield. ciencia rural. 31(1): 159-168. shafi, m., j. bakht, s. ali, h. khan, m.a. khan and m. sharif. 2012. effect of planting density on phenology, growth and yield of maize (zea mays l.). pak. j. bot. 44(2): 691-696. stephanus, j., haarhoff and p.a. swanepoel. 2018. plant population and maize grain yield: a global systematic review of rainfed trials. j. crop sci. 58: 1819–1829. tajul, m.i., m.m. alam, s.m.m. hossain, k. naher, m.y. rafii and m.a. latif. 2013. influence of plant population and nitrogenfertilizer at various levels on growth and growth efficiency of maize. sci world j. 2013(1):19. troyer, a.f. 1999. background of u.s. hybrid maize. crop sci., 39: 601–626. watson, s.a. 1988. maize marketing, processing, and utilization. in: g.f. sprague and j.w. dudley (eds.) maize and maize improvement, 3rd edn. asa, cssa, sssa, madison, wi. pp. 881–940. zamir, m.s.i., a.h. ahmad, m.r. javeed and t. latif. 2011. growth and yield behaviour of two maize hybrids (zea mays l.) towards different plant spacing. cercetari agronomice in moldova, 14(2): 33-40. zeleke, a., g. alemayehu and g.s. yihenew. 2018. effects of planting density and nitrogen fertilizer rate on yield and yield related traits of maize (zea mays l.) in northwestern, ethiopia. adv. crop sci. technol. 6: 352. bangladesh agron. j. 2024, 27(1): 40-47 mitigation of salt stress in proso millet (panicum miliaceum l.) by exogenous application of ascorbic acid m.m. alam, a.a.c. masud and mirza hasanuzzaman* department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: mhzsauag@yahoo.com (received: 1 january 2025, accepted: 16 april 2025) keywords: ascorbic acid, salinity, spad value, relative water content abstract salinity is one of the most detrimental environmental factors that limits the growth and productivity of crops. ascorbic acid (asa) is a vital antioxidant of plants, which prevents the oxidative damage caused by salinity and improves plant growth performance. a semi-controlled experiment was conducted to evaluate the impact of salt stress (150 and 300 mm nacl; s1 and s2, respectively) and asa (250 and 500 μμ; asa1 and asa2, respectively) on the seedling growth, physiological attributes, and yield of proso millet. the present study revealed that the salinity hampered the physiological processes and resulted in the reduction in yield attributes, while the application of asa in salt-stressed plants improved the plant height, fresh and dry weight, leaf relative water content (rwc) and spad value, as well as yield contributing attributes. foliar applications asa at 10 days intervals for two times reported with enhanced plant parameters. furthermore, the highest plant growth and yield attributes were observed while plants were sprayed with 500 μμ asa under salt stress. this study indicated that the exogenous addition of asa can be a useful strategy to promote plant phenotypic characters and yield contributing characters of proso millet cultivated under saline regimes. introduction salt stress is one of the most common, prevalent, and serious forms of abiotic stress that is destructive and causes severe crop losses in arid and semi-arid parts of the world (soliman et al., 2020). it is assumed that worldwide around 6% of total cultivable area has been infected by salinity that causing retarded plant growth and development in different crops (yang and guo 2017; zhang et al., 2021). the salt effect and its injury mechanism is quite complex to understand in plants as it integrates several morphological and physiological alterations in plants at cellular levels. high soil salinity leads to ion imbalances, osmotic stress, oxidative damage, and disruption of various physiological processes in plants (morton et al., 2018; mushtaq et al., 2025). generally, the cumulation of sodium (na+) and chloride (cl−) ions are the main malefactors accountable for salt toxicity in crops. plants exposed to salt may subsequently affect the major plant processes, including ion compartmentalization, nutrient assimilation, protein synthesis, photosynthesis, and hormonal balance (farooq et al., 2015). salt stress also triggers oxidative stress in plants. the high salt concentration stimulates the production of reactive oxygen species (ros), including superoxide radicals (o2 ●−) and hydrogen peroxide (h2o2), which can cause oxidative damage to cellular components. ros accumulation leads to lipid peroxidation, protein degradation, dna/rna damage, and overall disruption of cellular functions (hasanuzzaman et al., 2022). ascorbic acid, a low-molecular-weight antioxidant, has gained attention as a potential strategy to alleviate abiotic stress-induced damage in plants in recent years. this organic compound possessing antioxidant attributes plays a crucial role in scavenging ros and protecting cells from oxidative stress (el-hawary et al., 2023; kanwal et al., 2024). apart from 41 alam et al. its antioxidant properties, asa plays a pivotal role in various aspects of plant biology, including photosynthesis, hormone regulation, enzymatic activities, cell division, cell expansion, regulation of flowering, leaf aging, and apical meristem formation (el-beltagi et al., 2020). additionally, it acts as a cofactor for enzyme activity. when exogenously applied, asa stimulates the production of endogenous asa within plant cells, thereby mitigating the detrimental effects of salt stress in numerous crop species (akram et al., 2017). in recent years, several studies have investigated the potential of exogenous asa application in mitigating salt stress in various plant species (xu et al., 2015). these studies have reported positive effects on plant growth, photosynthesis, antioxidant defense systems, and ion homeostasis under salt stress conditions. proso millet (panicum miliaceum l.) is an important cereal crop known for its adaptability to diverse environmental conditions, including marginal lands with limited access to water and poor soil quality (saleem et al., 2023; samineni et al., 2025). however, proso millet is also sensitive to salt stress, which limits its cultivation in saline-affected areas. the specific role of asa in proso millet and its effectiveness in alleviating salt stress remain relatively unexplored. understanding the effects of salt stress in proso millet is crucial for developing effective strategies to mitigate its impact. by gaining insights into the underlying morpho-physiological and yield responses, researchers and farmers can explore innovative approaches to enhance millet's tolerance to salt stress, improve crop productivity, and ensure food security in regions affected by salinity. considering this, the experiment was conducted to know the effects of the application of asa under varying salinity levels in proso millet cultivation. materials and methods plant material and treatments healthy proso millet seeds (panicum miliaceum l. var. bari cheena-1) were carefully selected and evenly planted in 16 l plastic pots. to nourish the plants, a combination of organic manure and chemical fertilizers, including urea, tsp, and muriate of potash, was applied as the initial dose. at the 20-days after sowing (das), salinity stress was induced in the plants, with treatments including a control group (0 mm nacl), mild salinity stress (150 mm nacl), and severe salinity stress (300 mm nacl). additionally, supplementation of asa (250 and 500 μm) was carried out at 10 and 20 das, both under normal and saline conditions. the experiment was executed using a completely randomized design (crd) with three replicates. estimation of plant phenotypical attributes the height of the proso millet plants was assessed at three time points: 20 das, 30 das, and at the time of harvest. a measuring scale was employed to gauge the vertical distance from the ground level to the highest point of the leaf on each individual proso millet plant. the average height measurements were derived from five proso millet plants that were randomly chosen within each plastic pot. after termination of the stress period, three plants from each treatment were gently uprooted, thoroughly washed and water was removed by pressing with a dry towel. the plants were weighed using a balance, followed by averaging to determine the fresh weight (fw) plant−1. the same samples after measuring the fw were subjected to oven drying at 80°c for 48 hours. later on, the samples were weighed again to obtain the dry weight (dw). the average dry weight was then recorded and used as the dw plant−1. measurement of spad values and relative water content five leaves, chosen at random from each pot, were selected for the measurement of their top, middle, and base sections. an spad meter (minolta camera co., osaka, japan) was employed for this purpose, and the readings from each section were subsequently averaged, following the approach outlined by yuan et al., (2016). to record the relative water content (rwc), five leaves from five plants from each treatment were randomly plucked and cleaned with a paper towel. the fw of the leaves was recorded immediately after plucking. then the mitigation of salt stress in proso millet by exogenous application of ascorbic acid 42 leaves were submerged in distilled water within a petri dish and kept for 24 hours. excess water from the leaf surfaces was soaked by the towel, and the turgid weight (tw) was measured. subsequently, the samples were dried in an oven for 72 hours to obtain the dw. the following formula by barrs and weatherley (1962) was employed to calculate the relative water content rwc (%) = (fw−dw)/(tw−dw) ×100 measurement of yield contributing parameters number of tiller hill−1, paniclae length, number of filled grains panicle−1, number of unfilled grains panicle−1, 1000-seed weight and gain yield were measured using standard procedures. statistical analysis all data of three replications were statistically analyzed by using staistix 10. data were analyzed and the mean difference was compared by least significant difference (lsd) test with the 5% level of significance. results and discussion salt stress has a detrimental effect on plant growth at different developmental stages. for the proso millet plant, while exposed to s1 and s2, plant height was reduced by 21 and 27% at 30 das, respectively. the highest reduction of plant height (29%) was observed at harvest while plants were exposed to 300 mm salt stress (s2). however, the application of asa gradually increased the plant height under salt stress at different intervals. although asa did not significantly increase plant height in the control condition, but its role under stress conditions was very prominent. the plant height gradually increased over time and the highest increase was observed at harvest while applied with asa1, which is 2 and 14% for s2 and s1, respectively (table 1). more specifically, asa1 was found to be more effective in increasing plant height, thus mitigating the negative effect of both doses of salt stress in proso millet. table 1. plant height at 30 das, 50 das and at harvest of proso millet under salt stress supplemented by ascorbic acid treatments plant height (cm) 30 das 50 das at harvest c 27.74±2.20ab 51.38±0.44a 74.60±1.39a asa1 29.15±0.42a 50.86±2.39a 76.15±0.69a asa2 27.75±1.61ab 51.35±0.99a 75.22±0.72a s1 23.34±0.68e 43.71±0.05c 62.45±1.79d s1+asa1 26.91±1.84bc 49.55±1.63a 71.02±1.52b s1+asa2 26.85±0.69bc 46.56±1.58b 67.05±0.18c s2 21.43±1.00f 39.08±0.58d 53.22±2.08e s2+asa1 25.35±1.16cd 46.44±0.61b 66.21±1.00c s2+asa2 23.88±0.63de 42.92±0.78c 61.28±0.34d here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 150 and 300 mm nacl stress, respectively. mean (±sd) was calculated from three replicates for each treatment. columns with different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. the imposition of osmotic stress resulting from salinity and ionic stress leads to an upsurge in the production of ros within plants. this, in turn, results in detrimental effects on cell organelles and membrane components, ultimately leading to cell and plant demise, particularly in cases of severe salinity stress (hasanuzzaman et al., 2021). in this experimental 43 alam et al. study, observed a significant reduction in plant height in response to salt stress. in severe stress conditions, the plant height decreased by 29% at the time of harvest (table 1). this decline may be attributed to the heightened formation of ions in the soil solution during the plant's developmental stages. however, when applied asa, commonly known as vitamin c, observed an improvement in plant height, both during the vegetative and reproductive stages. this enhancement in plant height might be linked to asa's role in facilitating early shoot formation during the seedling stage (abdullah et al., 2021). plant biomass has significantly reduced due to prolonged salt stress. however, plant dw was largely reduced under s2 condition compared to plant fw. the highest reduction of fw and dw was 32 and 37%, respectively, under the s2 condition. exogenous foliar application of asa significantly increased plant fw and dw under both levels of stress condition. the highest increase of fw and dw (24 and 27%, respectively) was observed while sprayed with asa1 under 300 mm salt stress (fig. 1). fig. 1. fresh weight (a) and dry weight (b) of proso millet under salt stress supplemented by ascorbic acid. here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 150 and 300 mm nacl stress, respectively. mean (±sd) was calculated from three replicates for each treatment. columns with different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. the impact of salinity stress on plant biomass was notably detrimental, as indicated by the results. however, when asa was applied to the foliage, it led to a substantial improvement in both plant fresh and dry weight. this enhancement can likely be attributed to the improved plant height and the increase in leaf rwc compared to the control treatment. furthermore, asa appears to mitigate the adverse effects of stress on the initial growth of seedlings, enabling them to better cope with unfavorable abiotic stress conditions as they progress into later growth phases (gallardo et al., 2001). consequently, the increased count of tillers may contribute to the development of more robust seedlings at the outset of the proso millet's growth cycle. relative water content is one of the vital indicators in stress conditions that determines how much water is uptaken by plant cells. results show that a significant reduction in leaf rwc was recorded while plants were exposed to both levels of salt stress. however, the maximum reduction (24%) of rwc was reporded in s2 condition, followed by an 18% reduction in s1 condition. in opposite, foliar application of asa significantly increased leaf rwc under both levels of stress condition, whereas the highest increase was observed with asa1 application (19 and 18%) in both s1 and s2, respectively. in the case of spad value, salt stress has similar negative effect under both levels of salt stress. salt stress reduced spad value by 15 and 22% under s1 and s2, respectively. although no significant changes were observed due to asa application under control condition, it had significantly increased spad value under stress condition. the highest increase of spad value (16%) was observed with asa1 applied under s2 stress condition (fig. 2). mitigation of salt stress in proso millet by exogenous application of ascorbic acid 44 fig. 2. rwc (a) and spad value (b) proso millet under salt stress supplemented by ascorbic acid. here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 150 and 300 mm nacl stress, respectively. mean (±sd) was calculated from three replicates for each treatment. barrswith different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. in this study observed a reduction in leaf rwc and spad values, which serve as indicators of the content of photosynthetic pigments in leaves when plants were subjected to saline soil conditions. this decline in photosynthetic pigments can likely be attributed to a decreased rate of light absorption necessary for the photosynthesis process, and it is closely linked to the reduction in rwc. an increased rate of photosynthesis relies on adequate water uptake (el-hadidi et al., 2018). the application of asa proved effective in mitigating the detrimental impact of salinity. it did so by promoting an increase in the synthesis and upregulation of photosynthetic pigments. notably, the content of photosynthetic pigments is a crucial parameter for assessing crop salt tolerance (yildirim et al., 2008). the exogenous application of asa is anticipated to regulate stomatal opening under stress conditions, subsequently reducing transpiration rates, maintaining turgor, and ultimately enhancing plant growth and productivity in stress-inducing environments (el-beltagi et al., 2022). when exposed to s1 and s2, plant tiller number was reduced by 27 and 43% at 30 das, 27 and 41% at 50 das, and 22 and 42% at harvest compared to the control. application of asa significantly increased the tiller number in plants where the highest increase was 34% followed by 23% with asa1 under s2 condition at 50 das and at harvest, respectively. interestingly, in the control condition, foliar application of asa had no significant effect (table 2). table 2. the number of tillers hill−1 at 30 das, 50 das, and at harvest of proso millet under salt stress supplemented by ascorbic acid treatments number of tiller hill−1 30 das 50 das at harvest c 1.46±0.03b 3.98±0.08a 3.70±0.05a asa1 1.60±0.06a 3.96±0.05a 3.69±0.10a asa2 1.48±0.04b 3.88±0.07a 3.64±0.08a s1 1.06±0.04d 2.91±0.08e 2.91±0.08c s1+asa1 1.26±0.03c 3.56±0.09b 3.41±0.08b s1+asa2 1.21±0.02c 3.27±0.05c 3.01±0.04c s2 0.83±0.02f 2.34±0.04g 2.14±0.03e s2+asa1 0.98±0.01e 3.12±0.01d 2.64±0.07d s2+asa2 0.93±0.03e 2.61±0.05f 2.54±0.08d here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 150 and 300 mm nacl stress, respectively. mean (±sd) was calculated from three replicates for each treatment. columns with different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. 45 alam et al. the number of tillers in proso millet plays a pivotal role in determining crop yield, and this parameter is particularly vulnerable to the adverse effects of salt stress. in this experiment, the most significant reduction in tiller count was observed during both the early vegetative stage and the later growth stages. this decline is likely closely linked to the plant's access to water, as higher salt concentrations create oxidative stress and cellular damage, leading to diminished plant growth (hasan et al., 2020). the application of asa had a positive impact on tiller numbers, which can be attributed to its supportive role in plant growth and development. it is conceivable that asa helps alleviate the detrimental effects of salt stress on plants by enhancing mineral uptake and content. under stress conditions, the filled grain number was significantly reduced, whereas the unfilled grain number marked a slight increase. at s1 and s2 stress, the filled grain number drastically reduced by 30 and 43%, respectively. on the contrary, the unfilled grain number increased its highest by 49% at s2 stress condition. however, asa application notably reduced the unfilled grain number and increased the filled grain number panicle−1 (fig. 3). fig. 3. the number of filled (a) and unfilled (b) grains panicle−1 of proso millet under salt stress supplemented by ascorbic acid. here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 50 and 300 mm nacl stress, respectively. mean (±sd) was calculated from three replicates for each treatment. barrswith different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. in the presence of salt stress, plant water uptake reduces due to the toxic nature of ions in saline conditions. this decline in water uptake can be linked to the observed decrease in the number of filled grains. the reduced water availability hampers cell enlargement and disrupts the translocation of nutrients from leaves to grains due to insufficient water supply (per et al., 2017). table 3. panicle length, 1000-grain weight and grain yield of proso millet under salt stress supplemented by ascorbic acid. treatments panicle length (cm) 1000 grain weight (g) grain yield pot−1 c 19.00±0.22a 4.11±0.03ab 5.44±0.10a asa1 19.11±0.49a 4.13±0.10a 5.51±0.05a asa2 18.98±0.57a 4.03±0.07b 5.50±0.16a s1 14.62±0.44d 3.09±0.05f 4.26±0.10d s1+asa1 16.59±0.35b 3.71±0.07c 4.94±0.14b s1+asa2 15.30±0.46c 3.43±0.03d 4.67±0.13c s2 11.82±0.24g 2.37±0.01h 3.13±0.10g s2+asa1 13.92±0.12e 3.21±0.07e 3.97±0.10e s2+asa2 12.93±0.29f 2.86±0.06g 3.71±0.09f here, asa1 and asa2 denote 250 and 500 μm ascorbic acid, while the s1 and s2 represent 150 and 300 mm nacl stress. mean (±sd) was calculated from three replicates for each treatment. bars with different letters are significantly different at p ≤ 0.05 applying fisher’s lsd test. in this experiment, salt stress led to a marked decrease in relative water content, which in turn resulted in a substantial reduction in the number of filled grains, especially under severe mitigation of salt stress in proso millet by exogenous application of ascorbic acid 46 stress conditions. however, the application of asa has a multifaceted impact on various crucial physiological processes in plants, including enhanced nutrient uptake and the reduction of na+ levels in the presence of salinity stress. furthermore, asa applications shift the selectivity of ion uptake, favoring k+ over na+ and consequently lowering the na+/k+ ratio. this adjustment in ion balance safeguard the integrity of the cell membrane from damage (el-nasharty et al., 2019). salt stress significantly reduced the yield contributing parameters. at severe stress s2, the reduction was highest, which is 38, 42, and 43% for panicle length, 1000-grain weight, and grain yield respectively. however, the application of asa1 significantly increased the panicle length by 18%, 1000-grain weight by 36%, and grain yield by 27% under 300 mm nacl stress condition (table 3). interestingly, no significant change in the above-mentioned yield contributing parameters were observed under control condition with foliar application of asa. the decline in both crop yield and its constituent factors when cultivated in salt-stressed soil may primarily be attributed to the diminished assembly and motivation of photoassimilation processes. this reduction ultimately culminates in the lowest values observed in the harvest index (el-nasharty et al., 2019). additionally, the reduction in yield can also be attributed to the adverse impact of salinity stress on various plant growth parameters and essential physiological processes. these include but are not limited to photosynthesis, water absorption capacity, and the filling of grains (taha et al., 2021). conclusion salt stress exerts significant adverse affects on plant growth and development, manifesting in reduced plant height and impeded water uptake. furthermore, it leads to a decrease in leaf photosynthesis, resulting in diminished grain quality and yield in proso millet. however, the findings from this study provide clear evidence that foliar application of ascorbic acid effectively mitigates the detrimental effects of salt stress on proso millet. this intervention improves tiller numbers and reduces the occurrence of unfilled grains. notably, a lower dose of ascorbic acid is more efficient in counteracting the effects of salt stress compared to higher concentrations. in summary, based on the preceding results and discussion, it can be concluded that foliar application of ascorbic acid at a concentration of 250 μm is highly effective in promoting the growth and enhancing yields of proso millet when confronted with salinity stress. acknowledgments the authors express their gratitude to the sher-e-bangla agricultural university research system (saures), dhaka-1207, bangladesh for their financial support. we would also like to extend special thanks to professor dr. kamrun nahar from the department of agricultural botany at sher-e-bangla agricultural university (sau) for her updates to the manuscript. additionally, we appreciate the assistance of ms students sarwar hosen, samiul alam, umme kulsum sabiha and faomida sinthi during the experimentation. references abdullah, h.a., m.s. faysal and h.s.m. al-rashedy. 2021. role of ascorbic acid in reducing the harmful effects of sodium chloride in triticum aestivum l. and trigonella foenum-graecum l. plants. egypt. j. bot. 61: 901-910. akram, n.a., f. shafiq and m. ashraf. 2017. ascorbic acid-a potential oxidant scavenger and its role in plant development and abiotic stress tolerance. front. plant sci. 8: 613. barrs, h.d. and p.e. weatherley. 1962. a re-examination of the relative turgidity technique for estimating water deficits in leaves. aust. j. biol. sci. 15(3): 413-428. 47 alam et al. el-beltagi, h.s., h.i. mohamed and m.r. sofy. 2020. role of ascorbic acid, glutathione and proline applied as singly or in sequence combination in improving chickpea plant through physiological change and antioxidant defense under different levels of irrigation intervals. mol. 25(7): 1702. el-beltagi, h.s., i. ahmad, a. basit, w.f. shehata, u. hassan, s.t. shah, b. haleema, a. jalal, r. amin, m.a. khalid, f. noor, h.i. mohamed. 2022. ascorbic acid enhances growth and yield of sweet peppers (capsicum annum) by mitigating salinity stress. gesunde pflanz. 74(2): 423-433. el-hadidi, e., t. el-zehery and r. al-wetwat. 2018. response of wheat plant to foliar application of organic acids under saline conditions. j. soil sci. agric. eng. 9(3): 135-143. el-hawary, m.m., o.s. hashem and m. hasanuzzaman. 2023. seed priming and foliar application with ascorbic acid and salicylic acid mitigate salt stress in wheat. agron. 13(2): 493. el-nasharty, a.b., s.s. el-nwehy, e.z.a.e.m.a. abou el-nour and a.i. rezk. 2019. impact of salicylic acid foliar application on two wheat cultivars grown under saline conditions. pak. j. bot. 51(6): 1939-1944. farooq, m., m. hussain, a. wakeel and k.h.m. siddique. 2015. salt stress in maize: effects, resistance mechanisms and management: a review. agron. sustain. dev. 35(2): 461-481. gallardo, k., c. job, s.p.c. groot, m. puype, h. demol, j. vandekerckhove and d. job. 2001. proteomic analysis of arabidopsis seed germination and priming. plant physiol. 126(2): 835-848. hasanuzzaman, m., m.r.h. raihan, a.a.c. masud, k. rahman, f. nowroz, m., rahman, k. nahar and m. fujita. 2021. regulation of reactive oxygen species and antioxidant defense in plants under salinity. int. j. mol. sci. 22(17): 9326. hasanuzzaman, m., n. ahmed, t. saha, m. rahman, k. rahman, m.m. alam, m.m., rohman and k. nahar. 2022. exogenous salicylic acid and kinetin modulate reactive oxygen species metabolism and glyoxalase system to confer waterlogging stress tolerance in soybean (glycine max l.). plant stress. 3: 100057. kanwal, r., m.f. maqsood, m. shahbaz, n. naz, u. zulfiqar, m.f. ali and m. jamil et al. 2024. exogenous ascorbic acid as a potent regulator of antioxidants, osmo-protectants, and lipid peroxidation in pea under salt stress. bmc plant biol. 24(1): 247. morton, m.j.l., m. awlia, n. al-tamimi, s. saade, y. pailles, s. negrao and m. tester. m. 2018. salt stress under the scalpel-dissecting the genetics of salt tolerance. plant j. 97(1): 148-163. mushtaq, n.u., s. saleem, a. manzoor, i. tahir, c.s. seth and r.u. rehman. 2025. physiological and biochemical perspective on silicon induced salt stress tolerance in proso millet. silicon. 17(6): 114. per, t.s., m. fatma, a. mohd. s. javied and n.a. khan. 2017. salicylic acid and nutrients interplay in abiotic stress tolerance. in: r. nazar, n. iqbal, n.a. khan. (eds.). salicylic acid: a multifaceted hormone. springer: singapore. 221-237. saleem, s., n.u. mushtaq, i. tahir and r.u. rehman. 2023. zinc mediated modulation of the ascorbate– glutathione cycle for salinity stress mitigation in foxtail millet (setaria italica l.). j. soil sci. plant nutr. 23(4): 5718-5739. samineni, s., s. gummadi, s. thushar, d.n khan, a. gkanogiannis, l.a. b.l. lavalle and r.k. singh. 2025. exploring proso millet resilience to abiotic stresses: high-yield potential in desert environments of the middle east. agron. 15(1): 165. soliman, m., a.a. elkelish, t. souad, h. alhaithloul and m. farooq. 2020. brassinosteroid seed priming with nitrogen supplementation improves salt tolerance in soybean. physiol. mol. biol. plants. 26(3): 501-511. taha, r.s., m.f. seleiman, a. shami, b.a. alhammad and a.h.a. mahdi. 2021. integrated application of selenium and silicon enhances growth and anatomical structure, antioxidant defense system and yield of wheat grown in salt-stressed soil. plants. 10(6): 1040. xu, y., q. xu, and b. huang. 2015. ascorbic acid mitigation of water stress-inhibition of root growth in association with oxidative defense in tall fescue (festuca arundinacea schreb.). front. plant. sci. 6: 807. yildirim, b., f. yasar, t. oezpay, d. tuerkoezue, o. terziodlu and a. tamkoc. 2008. variations in response to salt stress among field pea genotypes (pisum sativum sp. arvense l.). j. anim. vet. adv. 7: 907-910. yuan, z., q. cao, k. zhang, s.t.a.u. karim, y. tian, y. zhu, w. cao and x. liu. 2016. optimal leaf positions for spad meter measurement in rice. front. plant sci. 7: 719. zhang, y, x. zhou, y. dong, f. zhang, q. he, j. chen, s. zhu and t. zhao. 2021. seed priming with melatonin improves salt tolerance in cotton through regulating photosynthesis, scavenging reactive oxygen species and coordinating with phytohormone signal pathways. ind. crops prod. 169: 113671. bangladesh agron. j. 2024, 27(2): 55-60 effect of different doses of herbicide (magzin 70 wg) to control weeds in brinjal field s.k. paul1,5, s.s. kakon1, m.r. karim1*, t.a. mujahidi2, s. mazumder4 and m.m. karim3 1agronomy division, bangladesh agricultural research institute, gazipur-1701, bangladesh 2bangladesh agricultural research institute, rars, hathazari, bangladesh 3oilseed research center, bangladesh agricultural research institute, gazipur-1701, bangladesh 4sher-e-bangla agricultural university, sher-e-bangla nagar, dhaka-1207, bangladesh 5the university of newcastle, callaghan, 2308, nsw, australia *corresponding author, email: mrkarimsau09@gmail.com (received: 9 september 2024, accepted: 31 march 2025) keywords: herbicide, weed management, brinjal, mbcr abstract effective weed management is always an important aspect in crop production. of the allpossible weed control techniques including physical, chemical, mechanical, cultural and biological, use of chemical is always prioritized first to the farmers due to its’ quick response and effective weed control efficacy. however, selection of an optimized dose for each herbicide is crucial considering its’ effectivity and eco-toxicological aspect. an experiment was conducted at the research field of agronomy division, gazipur during the rabi season of 2013-2014 to find out the optimum rate of herbicide (magzin 70 wg) to control weeds in brinjal field. six treatments viz.: (i) magzin 70 wg @ 750 ml ha−1 spraying at 15 das and 45 das, (ii) magzin 70 wg @1000 ml ha−1 spraying at 15 das and 45 das, (iii) magzin 70 wg @1250 ml ha−1spraying at 15 das and 45 das, (iv) magzin 70 wg @ 1500 ml ha−1 spraying at 15 das and 45 das, (v) two hand weedings at 30 and 60 das, (vi) no weeding (control) were used in the experiment. among the weed species, bathua (chenopodium album), durba (cynodon dactylon), anguli (digitaria sanguinalis), helencha (jussiaea repens), hatishur (heliotropium indicum), shama (echinochloa crusgalli), swetlomy (gnaphalium japonicum), mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (eleusine indica), bon masur (vicia sativa) were dominant in brinjal field. the results showed that the highest dry weight of weeds at 30 and 60 das were 12.24 gm m−2and 24.12 gm m−2, respectively found in control plot whereas the lowest with two hand weeding at 30 and 60 das. the maximum weed control efficiency (wce) over control both at 30 and 60 das were 79.41 and 74.32%, respectively in treatment two hand weeding at 30 and 60 das. the highest number of fruits plant−1 (11.05), single fruit weight (86.48 g), fruit length (24.09 cm), yield (14.56 t ha−1) was found in two hand weeding and the lowest in no weeding (control). though the wce was highest in two hand weeding, but due to higher labor cost, the maximum benefit cost ratio (mbcr) (1.26) was highest in application of magzin 70 wg@ 1500 ml ha−1 spraying at 15 and 45 das. as a system of mechanization of agriculture, the labor unavailability is a serious problem in bangladesh. so, use of magzin 70 wg@ 1500 ml ha−1 spraying at 15 das and 45 das may be economically viable. introduction brinjal (solanum melongena l.) is one of the most important, widely and round the year cultivated popular vegetable in bangladesh. it facing problem of weed population that limits the potential yield (paul et al., 2015a, paul et al., 2015c, paul et al., 2015b, hajong et al., 2016). it grows well in winter season. but it can be grown in all seasons. though it grows well year-round, but weed decreases the yield of brinjal drastically (paul, 2013, paul et al., 2017, paul et al., 2024a, paul et al., 2024b). there are many factors responsible for low yield, of 56 paul et al. which weed, the natural enemy of brinjal that reduces its yield if not properly controlled. crop management practices play an important role in crop production of which weed control is an important task which involves a lot of production cost due to unavailability of human labor in the world as well as bangladesh (paul et al., 2022, paul et al., 2023, paul et al., 2024a, paul et al., 2024b). as a result, the alternative way to control weeds by the use of herbicide is gradually increased. the excess use of herbicide to control weeds is hazardous for health and causes environmental pollution (paul, 2013, uddin et al., 2016, haque, 2017., paul et al., 2019). so, in chemical weed control method the first priority is to determination of optimum doses of herbicide (paul et al., 2017, kobir et al., 2019, kumar paul et al., 2023, paul et al., 2023). magzin 70 wg is a selective herbicide and effective for control of most broad leaf and sedge weeds in brinjal field. in crop production there are many causes of yield loss, of which weed is one of the most important one (mondal et al., 2015, paul et al., 2015c, mondal et al., 2016). oerke and dehne (1997) found that weeds cause around 33% of total crop loss in asia and other countries. on an average 37.3% of crop produce is damaged by weeds in bangladesh. production losses in bangladesh due to weeds as 33.2% in food crops, 41.3% in cereals, 31.9% in pulses, 40.8% in oilseed crops, 34.2% in fibre crops and 40.3% in rice (paul et al., 2015a). however, an average of 13.1% of crop reproduce is actually lost in the farmers’ fields even after adopting traditional weed control measure infestation of sedge weeds mainly cyperus rotundus was very serious at faridpur where density 290.83 m−2 and green weight 287.13 gm m−2 were observed at 1st weeding and second weeding it was 227.64 m−2 and green weight 272.17 gm m−2. it is assumed that in comparison to manual weeding, magzin 70 wg may provide more effective, economic and easier solution for weed management in brinjal. considering the above facts, the trial was undertaken to determine the optimum doses of herbicide (magzin 70 wg) on field for achieving its potential yield. materials and methods the experiment was conducted at the agronomy research field of bangladesh agricultural research institute, joydebpur, gazipur during the period from november 2013 to may 2014. six treatments viz., (t1) magzin 70 wg @ 750 ml ha−1 spraying at 15 (days after sowing) das and 45 das, (t2) magzin 70 wg @ 1000 ml ha−1spraying at 15 das and 45 das, (t3) magzin 70 wg @ 1250 ml ha−1 spraying at 15 das and 45 das, (t4) magzin 70 wg @ 1500 ml ha−1spraying at 15 das and 45 das, (t5) two hand weedings at 30 and 60 das and (t6) no weeding were in the study. the brinjal seedlings (var. bari begun-10) transplanted on 26 november 2013 maintaining 75cm × 60cm spacing where 80-60-40-20 kg n-p2o5-k2o-s ha−1. three irrigations were given to the crop at 21, 55 and 75 das were given. weed samples were collected at 30 das and 60 das. data on yield components were taken and analyzed statistically using mstat-c program. the relative density (rd) and weed control efficiency (wec) were calculated by the following formula. relative density (rd) = no. of specific weed species total no. of weeds ×100 weed control efficiency (wec) = dry wt. of control plot -dry wt. of specific plot dry wt. of control plot ×100 results and discussion major weeds flora found in the experiment plots are i.e. bathua (chenopodium album), durba (cynodon dactylon), anguli (digitaria sanguinalis), helencha (jussiaea repens), hatishur (heliotropium indicum), shama (echinochloa crusgalli), swetlomy (gnaphalium japonicum), effect of different doses of herbicide to control weeds in brinjal field 57 mutha (cyperus rotundus), shaknote (amaranthus viridis), gaicha (paspalum commersonii), chapra (eleusine indica), and bon masur (vicia sativa) (table 1). table 1. weed infestation in brinjal field at 30 das and 60 das during the rabi season 2013-2014 treatment weeds species no. of weeds m−2 relative density (%) local name scientific name 30 das 60 das 30 das 60 das t1 bathua chenopodium album (l.) 2 6 2.74 5.77 durba cynodon dactylon 14 17 19.18 13.46 anguli digitaria sanguinalis 3 6 4.11 5.77 helencha jussiaea repens 3 7 4.11 6.73 hatishur heliotropium indicum 1 3 1.37 2.88 shama echinochloa crusgalli 25 32 34.24 30.77 bangchora ageratum conyzoides 3 4 4.11 3.84 swelomy gnaphalium japonicum 0 1 0 0.96 mutha cyperus rotundus 3 7 4.11 6.73 shaknote amaranthus viridis 1 2 1.37 1.92 gaicha paspalum commersonii 2 1 2.74 0.96 chapra eleusine indica 16 18 21.92 17.31 bon masur vicia sativa 2 1.92 total 73 104 100 100 t2 bathua chenopodium album (l.) 1 2 2.13 2.78 durba cynodon dactylon 5 9 10.64 12.50 anguli digitaria sanguinalis 0 3 0 4.17 helencha jussiaea repens 6 12 12.76 16.67 hatishur heliotropium indicum 0 3 0 4.17 shama echinochloa crusgalli 12 9 25.53 12.50 bangchora ageratum conyzoides 0 2 0 2.98 swetlomy gnaphalium japonicum 5 7 9.6 8.86 mutha cyperus rotundus 11 14 18.41 19.64 shaknote amaranthus viridis 3 7 5.38 9.92 gaicha paspalum commersonii 1 3 2.13 4.37 chapra eleusine indica 6 4 12.76 6.11 bon masur vicia sativa 2 4 4.26 5.55 total 52 79 100 100 t3 bathua chenopodium album (l.) 6 8 13.95 15.68 durba cynodon dactylon 5 6 11.65 11.76 anguli digitaria sanguinalis 2 3 4.65 5.89 helencha jussiaea repens 2 2 4.65 3.92 hatishur heliotropium indicum 2 3 4.65 5.89 shama echinochloa crusgalli 10 8 23.25 15.68 bangchora ageratum conyzoides 4 7 9.30 13.72 swetlomy gnaphalium japonicum 1 2 2.27 3.84 mutha cyperus rotundus 2 3 4.65 5.89 shaknote amaranthus viridis 3 3 6.98 5.89 gaicha paspalum commersonii 1 2.27 chapra eleusine indica 8 8 18.60 15.68 bon masur vicia sativa 1 3 2.32 5.89 total 45 54 100 100 t4 bathua chenopodium album (l.) 1 2 4.55 6.90 durba cynodon dactylon 1 3 4.55 10.34 anguli digitaria sanguinalis 1 3 4.55 10.34 helencha jussiaea repens 5 3 22.72 10.34 hatishur heliotropium indicum 2 6.90 shama echinochloa crusgalli 3 5 13.63 17.24 bangchora ageratum conyzoides 1 4.55 swetlomy gnaphalium japonicum 2 6.90 mutha cyperus rotundus 6 5 27.27 17.24 shaknote amaranthus viridis 4 18.18 gaicha paspalum commersonii 2 6.90 58 paul et al. treatment weeds species no. of weeds m−2 relative density (%) local name scientific name 30 das 60 das 30 das 60 das chapra eleusine indica 5 17.24 bon masur vicia sativa 1 2 4.55 6.90 total 25 30 100 100 t5 bathua chenopodium album (l.) 1 3 3.57 9.67 durba cynodon dactylon 1 2 3.57 6.45 anguli digitaria sanguinalis 1 1 3.57 3.22 helencha jussiaea repens 11 8 39.29 25.82 hatishur heliotropium indicum 1 2 3.57 6.45 shama echinochloa crusgalli 1 3.22 bangchora ageratum conyzoides 4 3 14.29 9.68 swetlomy gnaphalium japonicum 1 2 3.57 6.45 mutha cyperus rotundus 3 9.68 shaknote amaranthus viridis 4 14.29 gaicha paspalum commersonii 1 3.57 chapra eleusine indica 2 6 7.14 19.36 bon masur vicia sativa 1 3.57 total 28 31 100 100 t6 bathua chenopodium album 7 9 6.14 5.45 durba cynodon dactylon 7 9 6.14 6.36 anguli digitaria sanguinalis 10 15 8.77 14.55 helencha jussiaea repens 6 8 5.26 7.28 hatishur heliotropium indicum 4 8 3.51 6.36 shama echinochloa crusgalli 31 26 27.19 22.73 bangchora ageratum conyzoides 14 2 12.29 1.81 swetlomy gnaphalium japonicum 1 2 0.88 1.81 mutha cyperus rotundus 8 12 7.01 10.91 shaknote amaranthus viridis 6 8 5.26 7.28 gaicha paspalum commersonii 2 2 1.75 0.91 chapra eleusine indica 12 10 10.54 10 bon masur vicia sativa 6 8 5.26 6.36 total 114 119 100 100 here, t1= magzin 70 wg @ 750 ml ha−1 spraying at 15 (days after sowing) das and 45 das, t2= magzin 70 wg @ 1000 ml ha−1spraying at 15 das and 45 das, t3= magzin 70 wg @ 1250 ml ha−1 spraying at 15 das and 45 das, t4= magzin 70 wg @ 1500 ml ha−1spraying at 15 das and 45 das, t5= two hand weedings at 30 and 60 das and t5= no weeding weed dry weight significantly influenced by different weeding methods (table 2). the highest dry weight of weeds at 30 and 60 das were 12.24 gm m−2 and 24.12 gm m−2 were found in control plot whereas the lowest weed dry weight in treatment two hand weeding. table 2. weed dry weight and control efficiency in brinjal field at 30 das and 60 das as affected by different doses of magzin 70 wg treatment at 30 das at 60 das weed dry weight (g m−2) wee control efficiency (%) weed dry weight (g m−2) weed control efficiency (%) t1 8.72 28.76 18.39 16.86 t2 5.64 53.92 12.24 44.66 t3 3.12 74.51 7.76 64.91 t4 2.88 76.47 6.57 70.29 t5 2.52 79.41 5.68 74.32 t6 12.24 22.12 here, t1= magzin 70 wg @ 750 ml ha−1 spraying at 15 (days after sowing) das and 45 das, t2= magzin 70 wg @ 1000 ml ha−1spraying at 15 das and 45 das, t3= magzin 70 wg @ 1250 ml ha−1 spraying at 15 das and 45 das, t4= magzin 70 wg @ 1500 ml ha−1spraying at 15 das and 45 das, t5= two hand weedings at 30 and 60 das and t6= no weeding effect of different doses of herbicide to control weeds in brinjal field 59 the highest number of fruits plant−1 (11.05), single fruit weight (86.48 g), fruit length (24.09cm), yield (14.56 t ha−1) was found in two hand weeding and the lowest in no weeding (control) (table 3). sustainable weed management is very much important for friendlyenvironment and biodiversity. table 3. fruit yield and yield contributing characters of brinjal as affected by different level of weed management practices treatment number of fruits plant−1 single fruit weight (g) fruit length (cm) fruit yield (t ha−1) t1 11.05 86.48 24.09 14.56 t2 14. 99 86.49 24.81 24.25 t3 16.85 86.88 24.92 27.52 t4 16.87 86.89 24.93 27.51 t5 17.36 87.53 24.91 28.47 t6 5.85 86.11 24.65 8.31 lsd (0.05) 0.59 2.66 0.16 1.28 cv% 1.79 1.61 0.33 2.37 here, t1= magzin 70 wg @ 750 ml ha−1 spraying at 15 (days after sowing) das and 45 das, t2= magzin 70 wg @ 1000 ml ha−1spraying at 15 das and 45 das, t3= magzin 70 wg @ 1250 ml ha−1 spraying at 15 das and 45 das, t4= magzin 70 wg @ 1500 ml ha−1spraying at 15 das and 45 das, t5= two hand weedings at 30 and 60 das and t6= no weeding the maximum wce over control both at 30 and 60 das were 79.41% and 74.32%, respectively in two hand weedings (table 4). though the wce was highest in two hand weedings, but due to higher labor cost and labor unavailability, the maximum benefit cost ratio (mbcr) was highest in teana 9ec @ 1500 ml ha−1 spraying at 15 and 45 das. results are in agreement with paul et al. (2015c). table 4. benefit-cost analysis of brinjal as influenced by different weed management practice treatment gross return (tk ha−1) total variable cost (tk ha−1) gross margin (tk ha−1) mbcr 1 2 3 4=1/2 t1 107,000 92,300 14,700 1.16 t2 111,000 92,500 18,500 1.20 t3 114,400 92,700 21,700 1.23 t4 116,600 92,900 23,700 1.26 t5 118,300 95,000 23,300 1.24 t6 95,000 89,900 5,100 1.06 note: price. 7.50 tk kg−1 brinjal, here, t1= magzin 70 wg @ 750 ml ha−1 spraying at 15 (days after sowing) das and 45 das, t2= magzin 70 wg @ 1000 ml ha−1spraying at 15 das and 45 das, t3= magzin 70 wg @ 1250 ml ha−1 spraying at 15 das and 45 das, t4= magzin 70 wg @ 1500 ml ha−1spraying at 15 das and 45 das, t5= two hand weedings at 30 and 60 das and t6= no weeding conclusion weed management is always an important aspect in crop production. of the allpossible weed control technique use of chemical is always prioritized first to the farmers due to its’ quick response and effective weed control efficacy. however, selection of an optimized dose for each herbicide is crucial considering its’ effectivity and eco-toxicological aspect. a chemical herbicide named magzin 70 wg was used to finalize an optimum dosage for weed control in brinjal field. the herbicide magzin 70 wg contains a new active ingredient named imazethapyr (imidazolinone), which is wg water dispersible granules, a new subclass of the hallucinogen persisting perception disorder (hppd)-inhibiting herbicide. as a result, the possibility of adverse effect of this herbicide is lower than other herbicides. from the experimental results and findings, it might be concluded that magzin 70 wg has effective 60 paul et al. weed control efficacy on different weed species in brinjal fields. it may be concluded that herbicide magzin 70 wg @ 1000-ml or 1250-ml ha−1 is applicable at 15 and 45 das to overcome labor shortage during weeding in brinjal field otherwise two hand weeding is preferable. it needs further trials to investigate eco-toxicological consequences to the environment and living organisms after application. references hajong, p., s. mondal, b. sikder, s.k. paul, and d. saha. 2016. existing value chain assessment of date palm is selected areas of greater jessore districts. j. sylhet agril. univ. 3(1): 53-58. haque, m.m. 2017. allelopathic effect of sorghum plants parts water extract to control weeds in wheat field. haya saudi j. life sci. 2(1): 6-9. kobir, m.s., m.r. rahman, a.m. islam, s. paul, m.m. islam, m.n. farid and p. hajong. 2019. yield performance of some maize varieties as influenced by irrigation management at different growth stages. res. agric. livest. fish. 6(1): 57-67. mondal, h., s. mazumder, s. roy, t. mujahidi and s. paul. 2015. growth, yield and quality of wheat varieties as affected by different levels of nitrogen. bangladesh agron. j. 18: 89-98. mondal, s., s. paul, d. saha, p. hajong and g. biswas. 2016. effect of conservation tillage practices and ipns based fertilizers management on the productivity of potato. j. sylhet agril. univ. 3(1): 3136. oerke, e.c. and h.w. dehne. 1997. global crop production and the efficiency of crop protection: current situations and future trends. european j. plant path. 103(3): 203-215. paul, s.k. 2013. allelopathic effects of rapeseed/mustard varieties on lentil and its associated weeds. department of agronomy. paul, s.k. and p.s. xy. 2022. rn controlled release formulation of herbicide: a safe technique for effective weed management practice. in: proceedings of the international cleanup conference. pp. 462-463. paul, s.k. and r. naidu. 2022. layered aluminosilicate nanoskeletons: the structure and properties of nanoherbicide formulations. adva. agron. 175: 301-345. paul, s.k., m. nuruzzaman., t.c., and r. naidu. 2019. aluminosilicate nano-skeleton to firm the structure and properties of nano-herbicide formulations. in: proceedings of the 8th international contamination site remediation conference. pp. 302-303. paul, s.k., s. akther, t.a. mujahidi. and s. kundu. 2017. effect of different doses of herbicide (metro 70wg) on weed control in maize field. bangladesh agron. j. 20(1): 109-111. paul, s.k., s. mazumder, s. mondal, s.k. roy and s. kundu. 2015a. intercropping coriander with brinjal forbrinjal fruit and shoot borer insect suppression. world j. agric. res. 11(5): 303-306. paul, s.k., s. mazumder, s. mondal, s.k. roy and s. kundu 2015b. intercropping coriander with chickpea for pod borer insect suppression. world j. agric. sci. 11(5): 307-310 paul, s.k., s. mazumder, t.a. mujahidi, s.k. roy and s. kundu 2015c. optimization of herbicide teana 9 ec dose for controlling weeds in brinjal. bangladesh agron. j. 18: 113-119. paul, s.k., s. mazumder. and r. naidu. 2024a. herbicidal weed management practices: history and future prospects of nanotechnology in an eco-friendly crop production system. heliyon.10(5). paul, s.k., y. xi, p. sanderson, a.k. deb, m.r. islam and r. naidu. 2023. investigation of herbicide sorption-desorption using pristine and organoclays to explore the potential carriers for controlled release formulation. chemosphere, 337, 139335. paul, s.k., y. xi, s. peter. and r. naidu. 2024b. controlled release herbicide formulation for effective weed control efficacy. sci. rep. 14(1): 4216. paul, s.k., y. xi., p. sanderson and r. naidu. 2023. investigation of the physicochemical properties of amine-modified organoclays influenced by system ph and their potential to adsorb anionic herbicide. geoderma, 436, 116560. uddin, r., m.s. islam, m.j. ullah, p.k.hore and s.k. paul. 2016. grain growth and yield of wheat as influenced by variety and sowing date. bangladesh agron. j. 18 (2)9: 7-104. bangladesh agron. j. 2024, 27(2): 108-115 effect of biochar and npk management on growth and yield of moringa (moringa oleifera) r.k. das1*, p.k. biswas1, m.s. islam1, t.s. roy1 and m.a. khan2 1department of agronomy, sher-e-bangla agricultural university, dhaka-1207, bangladesh 2department of soil science, sher-e-bangla agricultural university, dhaka-1207, bangladesh *corresponding author, email: ranjondash@yahoo.com (received: 30 july 2025, accepted: 28 august 2025) keywords: nutrient management, growth, yield, moringa abstract a field experiment was conducted at ukhiya, cox’s bazar, bangladesh, during 2022-2024 to evaluate the performance of moringa oleifera var. pkm-2 under different bamboo biochar and npk fertilizer treatments. the experiment was laid out in a randomized complete block design with three replications, consisting of four biochar doses (0, 5, 10, and 15 t ha−1) and four npk fertilizer levels (0, 50, 100, and 150% of the recommended fertilizer dose, rfd), resulting in 16 treatment combinations. results revealed that both biochar and npk significantly improved plant growth and yield attributes. application of 10-15 t ha−1 biochar enhanced plant height, crown spread, pod number, pod length and 1000-seed weight compared to the control. fertilizer application at 100-150% rfd increased vegetative growth, pod development, and seed yield. among the interactions, 10 t ha−1 biochar with 100% rfd produced the highest pod number (90 plant−1) and longest pods (55.69 cm), while 10 t ha−1 biochar with 150% rfd resulted in the tallest plants (3.95 m at 24 months). the heaviest seeds (140.54 g per 1000 grains) were recorded with 15 t ha−1 biochar. these findings suggest that 10 t ha−1 bamboo biochar combined with 100-150% rfd is optimal for maximizing moringa productivity under coastal agro-ecological conditions of cox’s bazar. introduction moringa (moringa oleifera lam.) is a fast-growing, drought-tolerant tree, valued for leaf, pod and seed uses in food, feed and nutraceuticals. its leaves and pods supply dense proteins, vitamins and minerals (notably ca, k, fe and provitamin a), making it a strategic crop for household nutrition and climate-resilient farming across south asia (moyo et al., 2011; gopalakrishnan et al., 2016; sultana, 2020 and pareek et al., 2023). in bangladesh, interest in moringa is rising as farmers diversify beyond rice and seek year-round, nutrient-rich produce under erratic rainfall and heat stress. the crop’s ability to thrive on relatively poor soils, coupled with high nutritional returns per unit area, underpins its appeal for coastal smallholders. coastal agro-ecosystems, including cox’s bazar, face soil constraints that can limit perennial tree-crop performance: coarse textures with low organic matter and nutrient stocks, and seasonal salinity pulses from tidal flooding and saltwater intrusion. empirical work from jhilwanja union (cox’s bazar) reports sandy to loam textures, very low organic matter and n, and low-to-moderate soil electrical conductivity, highlighting the need for amendments that build carbon, water retention, and cation exchange capacity (hossain et al., 2015). at a broader scale, projections indicate substantial salinity intensification across coastal bangladesh by mid-century, with implications for crop productivity without adaptive soil management (dasgupta et al., 2015). biochar, a carbon-rich, porous material from biomass pyrolysis, has emerged as a practical soil amendment to address exactly these constraints by improving soil structure, waterholding, ph buffering, and nutrient retention. field meta-analyses showed that biochar can raise yields particularly in tropical, low-fertility soils (jeffery et al., 2017) and that pairing biochar with mailto:ranjondash@yahoo.com 109 das et al. mineral fertilizers enhances crop response and nutrient-use efficiency (faloye et al., 2017; ye et al., 2020). bamboo-derived biochar is especially attractive in south asia due to abundant feedstock and favorable physicochemical properties; recent studies document improvements in soil water retention, ph moderation and microbial activity with bamboo biochar additions (yadav and bag, 2023; zhang et al., 2024). complementarily, judicious npk fertilization is known to boost moringa growth and yield traits (atteya et al., 2021). against this backdrop, the present study evaluates how different rates of bamboo biochar and npk, influence moringa growth and yield, separately and in combination under coastal soil conditions typical of cox’s bazar. materials and methods the field experiment was conducted during 2022-2024 at ukhiya, cox’s bazar, bangladesh. the test crop was moringa oleifera (var. pkm-2). seeds were collected from a reliable local source, soaked in water for 24 h, pre-germinated in gunny bags for 48 h, and then sown in a nursery bed on 8 april 2022. thirty-day-old seedlings were transplanted into the main field on 4 may 2022 at a spacing of 2.5 m × 2.5 m. the experiment was laid out in a randomized complete block design (rcbd) with two factors and three replications. factor a was biochar dose, with four levels: a₀ = 0 t ha−1(control), a₁ = 5 t ha−1, a₂ = 10 t ha−1, and a₃ = 15 t ha−1. factor b was npk fertilizer dose, with four levels: b₀ = 0% of recommended fertilizer dose (rfd), b₁ = 50% rfd, b₂ = 100% rfd, and b₃ = 150% rfd. this resulted in 16 treatment combinations: a₀b₀, a₀b₁, a₀b₂, a₀b₃; a₁b₀, a₁b₁, a₁b₂, a₁b₃; a₂b₀, a₂b₁, a₂b₂, a₂b₃; a₃b₀, a₃b₁, a₃b₂, and a₃b₃. land was prepared with a power tiller on 17 april 2022, sun-dried for one week, then harrowed and cross-ploughed. bamboo biochar was incorporated into the soil as pre-treatment. npk fertilizers were applied using urea (n), tsp (p), and mop (k) to supply target nutrient levels of 150 kg n, 50 kg p and 75 kg k ha−1, adjusted to the treatment levels (0-150% of rfd). the unit plot size was 2.0 m × 2.0 m with 1.5 m spacing between blocks and 1.0 m between plots to reduce border effects. irrigation and drainage were managed according to seasonal conditions, with drainage channels maintained during the rainy season. manual weeding was performed at approximately 30 and 60 days after transplanting (dat). pest monitoring was done regularly, but no insecticides were applied. plants were harvested at physiological maturity when 80-90% of pods had matured. pods were collected from the central 1 m area of each plot, dried and weighed. seeds were dried to 14% moisture content before weighing. five plants per plot were randomly selected for detailed observations. the data recorded included plant height (m) at 6, 12, 18, and 24 months; crown spread (m); stem girth (cm at 15 cm height); number of leaves plant−1; fresh leaf weight (g plant−1); number of pods plant−1; pod length (cm, average of five pods); fresh pod weight (g plant−1); and 1000seed weight (g). data were subjected to analysis of variance (anova) following the rcbd twofactor design. mean separation was carried out using the least significant difference (lsd) test at the 5% level of probability. results and discussion effect of biochar doses relative to a₀, biochar enhanced vegetative growth and reproductive traits throughout 6-24 months (tables 1-4). by 24 months, plant height rose from 3.36 m (a₀) to 3.69 m (a₂) and 3.67 m (a₃) (table 1); canopy size increased from 318 to ~387-389 leaves plant−1 under a₂-a₃, with leaf mass rising from 132.14 g (a₀) to 180.68 g (a₂) (table 2). reproductive gains followed: pods plant⁻¹ increased from 62.08 (a₀) to 73.75 (a₂) and 72.25 (a₃), and pod length from 48.57 cm (a₀) to ~50-51 cm (a₂-a₃) (table 3). seed traits improved, with 1000-seed weight moving from 121.99 g (a₀) to 140.54 g (a₃) (table 4). effect of biochar and npk management on growth and yield moringa 110 table 1. effect of biochar, npk doses and their interaction on plant height of moringa treatments plant height (m) at 6 months 12 months 18 months 24 months biochar effect a0 1.26 b 2.02 b 2.70 c 3.36 b a1 1.52 a 2.31 a 2.92 b 3.64 a a2 1.56 a 2.32 a 3.03 a 3.69 a a3 1.36 b 2.26 a 3.09 a 3.67 a cv (%) 11.9 6 5.72 2.91 4.83 se (±) 0.05 0.04 0.02 0.05 npk effect b0 1.32 b 2.02c 2.67 d 3.45 b b1 1.42 ab 2.20b 2.87 c 3.52 b b2 1.49 a 2.38a 3.05 b 3.58 b b3 1.46 ab 2.31a 3.15 a 3.82 a cv (%) 11.96 5.72 2.91 4.83 se (±) 0.05 0.04 0.02 0.05 interaction effect a0b0 1.12 cd 1.65 g 2.28 j 3.14 d a0b1 1.41 bc 1.987 f 2.72 hi 3.34 cd a0b2 1.02d 1.98 f 2.79 gh 3.35 cd a0b3 1.49 b 2.46 b 2.99 cdef 3.61 bc a1b0 1.36 bc 2.14 def 2.63 i 3.61 bc a1b1 1.52 b 2.17 def 2.86 fgh 3.57 bc a1b2 1.52b 2.497 b 3.07 bcde 3.53 bc a1b3 1.66 ab 2.42 bc 3.13 bcd 3.86 ab a2b0 1.41 bc 2.08 ef 2.85 fgh 3.48 c a2b1 1.39 bc 2.35 bcd 2.93 efg 3.49 c a2b2 1.88 a 2.83 a 3.20 ab 3.84 ab a2b3 1.54 b 2.02 f 3.15 bc 3.95 a a3b0 1.39 bc 2.20 cdef 2.91 efg 3.57 bc a3b1 1.36 7bc 2.3 bcde 2.98 def 3.67 abc a3b2 1.53 b 2.21 cdef 3.14 bc 3.58 bc a3b3 1.13 cd 2.33 bcd 3.34 a 3.85 ab cv (%) 12.1 5.72 2.91 4.83 se (±) 0.03 0.07 0.05 0.01 in a column, means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. (a0:0 t ha−1, a1: 5 t ha−1, a2: 10 t ha−1, a3: 15 t ha−1and b0:0% of rfd, b1: 50% of rfd, b2: 100% of rfd, b3: 150% of rfd). these outcomes agree with evidence that biochar improves soil moisture retention, cation-exchange capacity, ph buffering and nutrient availability, thereby supporting larger canopies and stronger sink formation (jeffery et al., 2017; ye et al., 2020). mechanistically, biochar can stabilize macro-aggregates and curb n losses, which reinforces sustained biomass and pod/seed filling over multiple seasons (khan et al., 2023; han et al., 2023). 111 das et al. table 2. effect of biochar, npk doses and their interaction on number of leaves plant−1 and weight of leaves of moringa treatments number of leaves plant−1 at weight of leaves (g) at 6 months 12 months 18 months 24 months 6 months 12 months 18 months 24 months biochar effect a0 33.42 c 127.08c 227.42 c 318 c 28.82 b 120.01 c 129.92 c 132.14 c a1 55.25 a 152.83 ab 241.25 b 351 b 35.20 a 148.61 b 161.83 b 166.83 b a2 53.58 a 149.00 b 253.50 a 387 a 35.32 a 166.62 a 181.26 a 180.68 a a3 46.50 b 153.08 a 252.42 a 389 a 27.38 c 149.91 b 164.50 b 165.20 b cv (%) 5.96 3.19 2.58 2.56 5.96 3.19 3 2.5 se (±) 0.81 1.34 1.82 1.89 0.81 1.34 2.11 1.92 npk effect b0 34.50 d 130.50 d 223.92 c 316c 29.09 c 127.57 c 138.56 c 140.36 c b1 51.42 b 140.08 c 236.83 b 337b 32.06 b 148.84 b 161.67 b 163.75 b b2 48.50 c 153.50 b 254.42 a 391a 31.11 b 148.19 b 160.73 b 161.69 b b3 54.33 a 157.92 a 259.42 a 412a 34.46 a 160.55 a 176.56 a 179.04 a cv (%) 5.89 3.05 2.12 2.07 4.56 2.74 4.3 4.86 se (±) 0.89 1.89 1.78 1.56 0.42 1.16 1.98 2.26 interaction effect a0b0 32.00 g 117.00 h 207.67 j 296.67 h 30.81 d 117.93 g 128.44 ef 108.01 j a0b1 27.67 gh 107.00 i 221.00 h 313.67 g 25.18 e 110.54 h 116.86 f 122.73 hi a0b2 24.00 h 137.00 fg 233.33 fgh 324.33 fg 21.97 f 109.27 h 117.73 f 124.61 ghi a0b3 50.00 e 147.33 de 247.67 cde 342.67 cd 37.32 bc 142.28 e 156.65 d 132.60 def a1b0 40.33 f 130.00 g 222.67 gh 317.33 fg 31.56 d 119.05 g 128.43 ef 120.62 i a1b1 66.67 ab 159.67 abc 235.00 efg 329.00 ef 35.81 c 156.86 c 172.12 bc 125.85 f-i a1b2 54.33 de 166.67 a 247.00 c-f 343.33 cd 36.67 c 153.54 cd 166.87 cd 134.48 de a1b3 59.67 c 155.00 bcd 260.33 bc 355.33 bc 36.76 c 164.97 b 179.92 b 139.67 cd a2b0 26.00h 136.33 fg 230.33 gh 318.67 fg 22.34 f 129.74 f 139.52 e 122.82 hi a2b1 52.33 e 144.67 ef 244.67 def 329.67 ef 37.60 bc 170.18 b 183.29 b 130.90 efg a2b2 71.33 a 152.67 cde 279.33 a 370.00 a 41.52 a 183.36 a 195.65 a 152.24 a a2b3 64.67 b 162.33 ab 259.67 bc 360.00 ab 39.84 ab 183.20 a 206.59 a 131.71 efg a3b0 39.67 f 138.67 f 235.00 efg 320.33 fg 31.65 d 143.56 e 157.84 d 128.49 e-h a3b1 59.00 cd 149.00 de 246.67 c-f 338.00 de 29.64 d 157.77 c 174.42 bc 139.60 cd a3b2 44.33 f 157.67 bc 258.00 bcd 351.00 bcd 24.29 ef 146.58 de 162.66 cd 144.50 bc a3b3 43.00f 167.00 a 270.00 ab 368.33 a 23.93 ef 151.74 cd 163.10 cd 149.55 ab cv (%) 5.96 3.19 2.58 2.16 4.56 2.74 4.29 3.16 se (±) 1.62 2.68 3.64 4.21 0.83 2.32 3.95 2.4 in a column, means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. (a0: 0 t ha−1, a1: 5 t ha−1, a2: 10 t ha−1, a3: 15 t ha−1 and b0: 0% of rfd, b1: 50% of rfd, b2: 100% of rfd, b3: 150% of rfd). effect of npk doses increasing fertilizer from b₀ to b₃ steadily raised plant stature and canopy size and improved pod traits (tables 1-3): at 24 months, height rose from 3.45 m (b₀) to 3.82 m (b₃) (table 1), leaves plant−1 from 316 (b₀) to 412 (b₃), and leaf mass from 140.36 g (b₀) to 179.04 g (b₃) (table 2). pods plant−1 climbed from 56.42 (b₀) to 78.67 (b₃), while pod length rose from 46.23 cm (b₀) to 51.79 cm (b₃) (table 3). for yield components, diminishing returns appeared effect of biochar and npk management on growth and yield moringa 112 at the highest dose: at 24 months pod weight peaked at b₁-b₂ (182.63-182.49 g) rather than b₃ (176.09 g) and 1000-seed weight plateaued at b₂-b₃ (~139 g) (table 4). table 3. effect of biochar, npk doses, and their interaction on number of pods plant−1 and length of pods of moringa treatments number of pods plant−1 at length of pods (cm) at 6 months 12 months 18 months 24 months 6 months 12 months 18 months 24 months biochar effect a0 1.25 c 16.50 d 42.50 c 62.08 c 2.79 c 25.54 d 36.47 c 48.57 c a1 2.25 b 19.92 c 46.75 b 66.58 b 2.33 c 27.41 c 38.12 b 49.98 b a2 3.25 a 21.17 b 46.42 b 73.75 a 3.65 b 29.13 b 39.41 a 51.38 a a3 2.83 a 22.33 a 49.17 a 72.25 a 4.49 a 30.12 a 40.34 a 50.70 ab cv (%) 21.04 5.48 2.75 4.17 10.54 2.32 3.06 2.74 se (±) 0.15 0.32 0.37 0.83 0.1 0.19 0.34 0.4 npk effect b0 1.25 c 14.17 d 38.08 c 56.42 c 2.55 c 24.30 d 35.20 d 46.23 c b1 2.25 b 18.33 c 44.58 b 63.83 c 2.24 d 26.97 c 37.51 c 49.83 b b2 2.58 b 22.08 b 50.83 a 75.75 b 4.06 b 29.52 b 39.82 b 52.79 a b3 3.50 a 25.33 a 51.33 a 78.67 a 4.40 a 31.42 a 41.81 a 51.79 a cv (%) 21.04 5.48 2.75 4.17 10.54 2.32 3.06 2.74 se (±) 0.15 0.32 0.37 0.83 0.1 0.19 0.34 0.4 interaction effect a0b0 2.00 d 12.00 i 34.33 g 53.00 k 5.06 b 22.18 g 33.35 i 45.00 d a0b1 0.00 f 16.00 g 39.67 f 59.33 ij 0.00 f 24.66 f 35.88 h 47.37 d a0b2 1.00 e 18.00 f 46.33 d 65.67 gh 4.05 c 26.58 e 37.31 fgh 50.12 c a0b3 2.00 d 20.00 e 49.67 bc 70.33 efg 2.06 e 28.73 d 39.35 def 51.81 bc a1b0 0.00 f 14.00 h 36.33 g 55.00 jk 0.00 f 24.13 f 35.35 h 45.53 d a1b1 2.00 d 18.00 f 44.00 e 61.67 hi 2.08 e 26.03 e 36.13 gh 49.69 c a1b2 3.00 c 22.33 d 50.67 b 72.00 ef 3.00 d 29.18 d 39.50 cde 52.02 bc a1b3 4.00 b 25.33 bc 56.00 a 77.67 cd 4.22 c 30.30 c 41.51 bcd 52.68 b a2b0 1.00 e 15.00 gh 39.33 f 57.67 ijk 1.98 e 24.82 f 35.95 h 47.05 d a2b1 3.00 c 19.00 ef 47.00 d 66.33 gh 3.12 d 28.38 d 38.18 efg 50.05 c a2b2 4.00 b 23.67 cd 51.33 b 90.00 a 4.21 c 30.60 c 40.83 bcd 55.69 a a2b3 5.00 a 27.00 b 48.00 cd 81.00 bc 5.28 b 32.72 b 42.68 ab 52.73 b a3b0 2.00 d 15.67 gh 42.33 e 60.00 ij 3.15 d 26.05 e 36.13 gh 47.35 d a3b1 4.00 b 20.33 e 47.67 cd 68.00 fg 3.77 c 28.80 d 39.87 cde 52.21 bc a3b2 2.33 cd 24.33 c 55.00 a 75.33 de 4.99 b 31.71 b 41.66 abc 53.32 b a3b3 3.00 c 29.00 a 51.67 b 85.67 ab 6.03 a 33.92 a 43.70 a 49.92 c cv (%) 21.04 5.48 2.75 4.17 10.54 2.32 3.06 2.74 se (±) 0.29 0.63 0.73 1.65 0.2 0.37 0.68 0.79 in a column, means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. (a0: 0 t ha−1, a1: 5 t ha−1, a2: 10 t ha−1, a3: 15 t ha−1 and b0:0% of rfd, b1: 50% of rfd, b2: 100% of rfd, b3: 150% of rfd). this pattern matches moringa studies where balanced n and p boost leaf growth and tissue nutrition, while adequate k underpins pod elongation, assimilate transport, and seed filling; excessive n can shift partitioning toward foliage at the expense of seed mass (kumar et al., 2006; atteya et al., 2021). 113 das et al. interaction of biochar and npk co-application produced the strongest outcomes, with a₂ × (b₂-b₃) and a₃ × b₃ repeatedly leading (tables 1-4). for height, a₂b₃ achieved the overall maximum of 3.95 m at 24 months (table 1). pod set and pod length peaked at a₂b₂ (90 pods plant−1; 55.69 cm), with a₃b₃ and a₁b₃ also high across stages (table 3). vegetative yield was likewise strongest under a₂b₂/a₂b₃ and a₃b₃ (table 2). an interesting exception is the very high pod weight at 24 months under a₀b₁ (204.99 g) (table 4), plausibly reflecting a source-sink compensation: with fewer pods and a lighter canopy, assimilates can be preferentially allocated to each pod, increasing unit mass (baï ram et al., 2019). table 4. effect of biochar, npk doses, and their interaction on pod weight and 1000-seed weight of moringa treatments weight of pods (g) at 1000 seeds weight (g) 6 months 12 months 18 months 24 months biochar effect a0 10.72 d 120.64 c 139.45 c 177.47 b 121.99 d a1 15.64 c 128.43 b 148.22 b 172.87 c 130.16 c a2 22.93 b 131.49 a 155.01 a 182.52 a 134.42 b a3 26.92 a 128.36 b 149.14 b 177.55 b 140.54 a cv (%) 9.95 1.91 1.73 1.61 3.16 se (±) 0.55 0.7 0.74 0.83 1.2 npk effect b0 11.67 d 121.04 d 142.43 b 169.19 c 119.98 c b1 15.18 c 123.56 c 143.01 b 182.63 a 129.77 b b2 21.96 b 133.34 a 153.73 a 182.49 a 138.96 a b3 27.39 a 130.98 b 152.66 a 176.09 b 138.38 a cv (%) 9.95 1.91 1.73 1.61 3.16 se (±) 0.55 0.7 0.74 0.83 1.2 interaction effect a0b0 12.91 gh 115.32 i 137.04 f 166.07 hi 108.01 j a0b1 0.00 i 108.40 j 121.26 g 204.99 a 122.73 hi a0b2 12.22 h 127.42 ef 147.59 de 172.74 fg 124.61 ghi a0b3 17.73 ef 131.43 de 151.92 cd 166.08 hi 132.60 def a1b0 0.00 i 120.39 h 139.81 f 164.02 i 120.62 i a1b1 15.83 fg 125.89 fg 144.91 e 171.25 fg 125.85 f-i a1b2 20.88 de 131.39 de 150.52 cd 174.65 efg 134.48 de a1b3 25.85 c 136.04 bc 157.64 b 181.56 cd 139.67 cd a2b0 15.38 fgh 122.54 gh 147.41 de 171.56 fg 122.82 hi a2b1 20.98 de 127.19 ef 153.78 bc 176.00 ef 130.90 efg a2b2 25.02 c 135.06 cd 154.12 bc 196.04 b 152.24 a a2b3 30.33 b 141.16 a 164.74 a 186.46 c 131.71 efg a3b0 18.39 ef 125.89 fg 145.46 e 175.13 efg 128.49 e-h a3b1 23.91 cd 132.77 cd 152.11 cd 178.27 de 139.60 cd a3b2 29.72 b 139.50 ab 162.68 a 186.53 c 144.50 bc a3b3 35.67 a 115.28 i 136.31 f 170.26 gh 149.55 ab cv (%) 9.95 1.91 1.73 1.61 3.16 se (±) 1.09 1.4 1.47 1.65 2.41 in a column, means having similar letter(s) are statistically similar and those having dissimilar letter(s) differ significantly at 0.05 level of probability. (a0: 0 t ha−1, a1: 5 t ha−1, a2: 10 t ha−1, a3: 15 t ha−1 and b0:0% of rfd, b1: 50% of rfd, b2: 100% of rfd, b3: 150% of rfd). overall, these patterns fit the well-documented synergy where biochar improves fertilizeruse efficiency, p availability and moisture buffering, delivering yield advantages beyond fertilizer alone across seasons (ye et al., 2020; faloye et al., 2017). practically, targeting a₂ with b₂-b₃ effect of biochar and npk management on growth and yield moringa 114 (≈10 t ha−1 biochar plus 100-150% rfd) appears optimal for maximizing combined growth, pod set and seed traits under comparable conditions. conclusion across 6-24 months, both biochar and npk fertilizer substantially improved moringa growth and yield. relative to no biochar and no fertilizer, applying 10-15 t ha−1 biochar together with 100-150% of the recommended fertilizer dose increased plant height, canopy size, leaf mass, pods per plant, pod length, pod weight and 1000-seed weight. the best overall performance occurred around 10 t ha−1 biochar combined with the recommended-supra fertilizer range:10 t ha−1 + 150% rfd produced the tallest plants at 24 months (3.95 m), while 10 t ha−1 + 100% rfd gave the highest pod number (90) and the longest pods (55.69 cm). vegetative traits (leaf number and leaf weight) were likewise strongest under 10-15 t ha−1 with 100-150% rfd. seed size peaked with 15 t ha−1 biochar (1000-seed weight 140.54 g) and plateaued near 100-150% rfd (~139 g). one notable exception was a very high pod weight under 0 t ha−1 biochar with 50% rfd (204.99 g), likely reflecting source-sink compensation rather than superior overall productivity. for similar environments, a practical recommendation is ~10 t ha−1 biochar with 100-150% of the recommended npk dose to maximize combined vegetative and reproductive performance. as this trial covered a single site-year within one aez, multi-year evaluations across additional aezs are advised before broad-scale recommendation. references atteya, a.k.g., e. el-shawy, t. alshaal and h. el-ramady. 2021. response of moringa oleifera seeds and fixed oil production to vermicompost and npk fertilizers under calcareous soil conditions. plants. 10(10): 1998. baï ram, e., c. lemorvan, m. delaire and g. buck-sorlin. 2019. fruit and leaf response to different sourcesink ratios in apple, at the scale of the fruit-bearing branch. front. plant sci. 10: 1039. dasgupta, s., m.m. hossain, m. huq and d. wheeler. 2015. climate change and soil salinity: the case of coastal bangladesh. ambio. 44(8): 815-826. faloye, o.t., m.o. alatise, a.e. ajayi and b.s. ewulo. 2017. synergistic effects of biochar and inorganic fertiliser on maize (zea mays) yield in an alfisol under drip irrigation. soil tillage res. 174: 214-220. gopalakrishnan, l., k. doriya and d.s. kumar. 2016. moringa oleifera: a review on nutritive importance and its medicinal application. food sci. human well. 5(2): 49-56. han, m., j. zhang, l. zhang and z. wang. 2023. effect of biochar addition on crop yield, water and nitrogen use efficiencies: a global meta-analysis. j. clean. prod., 420: 138425. hossain, n., m. muhibbullah, k.m.b. ali and m.h. molla. 2015. relationship between soil salinity and physico-chemical properties of paddy field soils of jhilwanja union, cox’s bazar, bangladesh. j. agri. sci. 7(10): 166. jeffery, s., d. abalos, m. prodana, a.c. bastos, j.w. van groenigen, b.a. hungate and f. verheijen. 2017. biochar boosts tropical but not temperate crop yields. environ. res. letters. 12(5): 053001. khan, z., x.j. yang, y. fu, s. joseph, m.n. khan, m.a. khan, i. alam and h. shen. 2023. engineered biochar improves nitrogen-use efficiency via stabilizing soil macro-aggregates and enhancing n transformation. biochar. 5(1): 52. kumar, a.r., n. kumar and m. kavino. 2006. role of potassium in fruit crops-a review. agric. rev. 27(4): 284-291. moyo, b., p.j. masika, a. hugo and v. muchenje. 2011. nutritional characterization of moringa oleifera leaves. african j. biotechnol. 10(60): 12925-12933. pareek, a., m. pant, m.m. gupta, p. kashania, y. ratan, v. jain, a. pareek, a.a. chuturgoon. 2023. moringa oleifera: an updated comprehensive review of pharmacological activities, ethnomedicinal uses, phytochemistry, and toxicology. int. j. mol. sci. 24(3):2098. sultana, s. 2020. nutritional and functional properties of moringa oleifera. metabolism open. 8: 100061. yadav, s.k. and r. bag. 2023. effect of bamboo biochar on strength and water retention properties of lowplastic clay and silty sand. sci. rep. 13(1): 6201. 115 das et al. ye, l., m. camps-arbestain, q. shen, j. lehmann, b. singh and m. sabir. 2020. biochar effects on crop yields with and without fertilizer: a meta-analysis of field studies using separate controls. soil use mng. 36(1): 2–18. zhang, s.h., y. shen, l.f. lin, s.l. tang, c.x. liu, x.h. fang, z.p. guo, y.y. wang and y.c. zhu. 2024. effects of bamboo biochar on soil physicochemical properties, enzymatic activity, and microbial community structure in tea garden soils. peer j. 12: e18642.