Bangladesh Agron. J. 2022, 25(2): 1-9 GROWTH AND YIELD RESPONSE OF SELECTED AMAN VARIETIES AS INFLUENCED BY LEAF CUTTING M.J. Hossain1§, A.A.C. Masud2*§, M.S. Islam2, S. Akhter3 and M.M. Haque1 1Department of Agricultural Botany, Sher-e-Bangla Agricultural University, Dhaka-1207 2Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka-1207 3Institute of seed technology, Sher-e-Bangla Agricultural University, Dhaka-1207 *Corresponding E-mail: chy.masud3844@sau.edu.bd (Received: 11 June 2022, Accepted: 05 December 2022) Keywords: Leaf removal, photo assimilation, modern rice, harvest index, flag leaf, penultimate leaf Abstract Sustainable crop production in the era of increasing input price is adding extra burden while the cultivable land is reducing at an alarming pace. This research article aims to test the hypothesis that the leaf cutting as an agronomic practice could be a better prospective in increasing rice grain production. An experiment was carried out in the experimental field of Sher-e-Bangla Agricultural University, to assess the effect of leaf cutting on plant growth and yield of selected BRRI released Aman varieties. The experiment consisted of five rice varieties namely BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, and BRRI dhan56 treated either as control or leaf cutting (except flag and penultimate leaf). The experiment was laid out in randomized complete block design (RCBD) with three replicates. Leaf cutting was observed with detrimental effect on the usual plant growth and yield performances. Irrespective of all studied varieties, the highest value was obtained while no leaf cutting was performed. BRRI dhan39 was found to be the highest yield producing variety in terms of greater flag leaf length, leaf breadth, flag leaf area, required less time to grain filling, filled grain panicle-1, filled grain%, 1000- grain weight, grain yield and harvest index in leaf cutting condition followed by BRRI dhan32 in terms of plant height, chlorophyll content, tiller hill-1 and straw yield. No significant differences in yield contributing parameters except the panicle hill-1 were observed in leaf cutting condition compared to control. Leaf cutting at heading (except flag leaf and penultimate leaves) reduced average 10-20% loss of grain yield. BRRI dhan62 shown highly affected by leaf cutting compared to the rest other varieties. Therefore, it can be concluded by suggesting that leaf cutting reduces plant functional efficiency which can be improved by enhancing photosynthetic capacity through proper management of leaf architecture. Introduction Rice (Oryza sativa L.) is the staple food for over half of the world population and is the second most common cereal crop in the world (Shang et al., 2020). Around 75% of agricultural land in Bangladesh is occupied by rice cultivation that contributes nearly 28% of the GDP (Mazumder et al., 2020). Ever increasing population is putting an extra pressure on cultivable land and is reducing cultivable land at 0.4% rate due to urbanization and industrialization (Karmakar and Karmakar, 2019). Thus, rice output must be increased urgently through yield maximization to ensure long-term food security. Proper agronomic management is necessary to maximize rice crop growth and grain yield. In Bangladesh rice cultivation varies due to seasonal change in water supply. During the growing season, the mean temperature, and the total temperature variation, range, distribution pattern, and diurnal changes, or a combination of these may be mailto:chy.masud3844@sau.edu.bd 2 Hossain et al. highly correlated with the grain yields of rice (Islam et al., 2019). Potential for increased rice production strongly depends on the ability to integrate a better crop management for the different varieties into the existing cultivation. Variety itself is a genetic factor which contributes a lot in producing yield and yield components of a particular crop (Mahmud et al., 2013). To increase cropping intensity and production, there is no alternative for cultivation of short duration variety and adoption of modern agricultural practices. There are several important factors those have tremendous influence on the growth and development, tiller production, grain formation and other yield contributing characters. Flag leaf is metabolically active and has proved that the flag leaf, stem and head are the closest source food to the grain (Rahman et al., 2013). Flag leaf contributed to 45% of grain yield and is the single most component for yield loss through synthesis and translocation of photo-assimilates to the rice grain (Das et al., 2017; Karmakar and Karmakar, 2019). The contribution of leaf removal in different rice cultivar was the minimum, suggesting the probability of maximum translocation of photosynthesis from stem to the grain during grain feeling stage of rice after leaf removal (Abou-khalifa et al., 2008). Since the productivity of a plant depends on the efficiency of its photosynthetic processes and therefore on the extent of its photosynthetic surface, the growth and development of leaves have a profound impact on the yield of the plant (Mazur et al., 2019). The top three leaves have the greatest impact on grain yield. As a result, a thorough investigation of rice yield after chopping flag leaf and surrounding leaves was conducted (Abou-khalifa et al., 2008). In order to improve rice grain yield, it is necessary to examine the morphological and physiological properties of functional leaves. Another significant chemical involved in photosynthesis in plant leaves is chlorophyll, which has a direct impact on crop biomass and production. Photosynthetic rate and chlorophyll content are linked. (Mahmud et al., 2013). If leaf removal has no influence on grain production, it might become one of the most cost-effective ways to boost yield, with the added benefit of providing green fodder for farm animals. Rice cultivation's effectiveness as a dual- purpose crop is largely determined by improved agronomic techniques and cutting time. For collecting enough fodder without reducing grain productivity, the timing of cutting rice leaves and the selection of an appropriate variety appear to be crucial. Considering the above facts, the present study was carried out to evaluate yield, yield related parameters and quality of selected rice cultivars as influenced by leaf cutting. Materials and Methods The experiment was conducted at the research field of Sher-e-Bangla Agricultural University, Dhaka from July to December, 2016. Five rice varieties released from Bangladesh Rice Research Institute (BRRI) were used as plant materials. The rice varieties used in the experiments were V1=BRRI dhan32, V2=BRRI dhan33, V3=BRRI dhan39, V4=BRRI dhan62, V5=BRRI dhan56. The seeds were collected from the BRRI, Joydebpur. The experiment consists of two factors, factor A: Five varieties, and factor B- Control (c), and leaf cutting (Lc; except flag and penultimate leaves). The experiment was laid out in randomized complete block design with three replications. Rice seedlings were sown in the seedbed under the supervision of farm management division of Sher-e-Bangla Agricultural University, Dhaka. As per BRRI recommendation seedbed was prepared with 1 m wide and added nutrients as per requirements of soil. Seed were sown in the seedbed @ 70 gm-2. The plot selected for the experiment was exposed to the sun for a week after initial soil opening. Later on, the land was harrowed, ploughed and cross-ploughed several times followed by laddering to obtain a good tilth condition. Weeds and stubble were removed and 10 tha-1 amounts of cowdung, TSP, MP, Gypsum and Zinc and 1/3 of urea were applied at the time of final land preparation at broadcasting method. Half of the rest 2/3 of urea was applied at 25 days after transplanting (DAT) and the rest amount of urea was applied at 45 Growth and Yield of Aman Varieties as Influenced by Leaf Cutting 3 DAT. The nursery bed was made wet by application of water one day before uprooting the seedlings. At 23 days after sowing, seedlings were uprooted and transplanted to the previously prepared main field, maintaining a distance of 25 cm × 20 cm. Two seedlings hill-1 were used during transplanting. Gap filling was done for all of the missing hills at 10 DAT by planting same aged seedlings. First weeding was done from each plot at 15 DAT and second weeding was done from each plot at 40 DAT. The rice plant was harvested depending upon the maturity of grains and harvesting was done manually from each plot. Maturity of crop was determined when 80-90% of the grains become golden yellow in color. Ten randomly selected hills per plot from which different data were collected and 3 m2 areas from middle portion of each plot was separately harvested and bundled, properly tagged and then brought to the threshing floor. Harvesting, threshing and cleaning of rice seed were done carefully. Fresh weight of grain and straw were recorded plot wise. Finally, the weight was adjusted to a moisture content of 13%. The data on plant height, leaf parameters, tiller hill-1, chlorophyll (chl) of flag leaf, panicle hill-1, grain panicle-1, grain filling time, filled and unfilled grain panicle-1 were collected before harvesting. After harvesting, the straw was sun dried and the yield parameter viz., grain yield, filled grain%, 1000-grain weight, straw yield, biological yield and harvest index were recorded accordingly. Chlorophyll content was measured on fresh weight basis extracting with 80% acetone and used doubled beam spectrophotometer (Model: U-2001, Hitachi, Japan) according to Witham et al. (1986). The total chlorophyll content was estimated by adding chl a and chl b. Harvest index was calculated dividing the grain yield by the total biological yield (grain and straw) of the same area and multiplying by 100. Harvest index (%) = × 100 The data obtained for different characters were statistically analyzed to observe the significant difference among the treatment (Statistix 10). The significance of the difference among the treatment means were estimated by the Least Significant Difference (LSD) test at 5% level of probability. Results and Discussion Effect of leaf cutting on growth parameters of rice Plant growth parameters were significantly influenced due to leaf cutting. Leaf cutting negatively impacted on different plant parameters. However, in all the tested parameters, the controls resulted with the highest performances compared to the respective other treatment. Therefore, here we will consider the highest and lowest values of the varieties while leaf cutting was performed. Plant height, leaf no. at heading The plant height of different varieties exhibited wide variation in length due to leaf cutting. The plant height was maximum (127.61 cm) in BRRI dhan33. The shortest plant height (97.26 cm) was found from BRRI dhan56. The remaining varieties were intermediate in this regard (Fig. 1A). The number of leaves produced at heading of different rice cultivars showed no significant variation due to leaf cutting. Therefore, less detrimental effect of leaf cutting was observed in varieties due to leaf cutting. However, the maximum numbers of leaves at heading (64.67) were produced by BRRI dhan62 which were statistically superior to the rest of the varieties. BRRI dhan32 and BRRI dhan39 produced second highest number of leaves which was also statistically different from the rest of the lines. The least number of leaves (53.67) produced by BRRI dhan56 while the other varieties took intermediate positions and they were statistically different among themselves (Fig. 1B). Confalonieri et al. (2011) detected plant height as a key factor to predict rice yield potential and established a model to estimate the plant height increase. Similarly, Karmakar and Karmakar (2019) reported that plant height was significantly affected by 4 Hossain et al. nitrogen rates and different leaf clipping times in BRRI dhan41. Suprio et al. (2010) also found effective grains per panicle revealed significant positive relationship with plant height. It indicated that increasing plant height increases effective panicles per plant. Fig. 1. Combined effect of varieties and leaf cutting on plant height (A) and leaf number at heading (B) of rice. Means with different letters are significantly different at P≤0.05 by LSD test. Here C, LC denotes control and leaf cutting, V1- V5; BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, BRRI dhan56, respectively. Leaf parameters (Leaf length, breadth and area) Leaf cutting significantly reduced the leaf length, breadth and area of flag leaf, penultimate and 3rd leaf in all five tested varieties compared to the control (Table 1). However, due to leaf cutting the highest reduction of leaf length in flag leaf, penultimate and 3rd leaf 22.24, 23.37 and 17.29% was observed in V5, V4 and V2 variety, respectively. On the contrary, the highest flag, penultimate and 3rd leaf length was observed in V3, V3 and V5 variety, respectively (Table 1). Leaf length is very important in rice because leaf length is positively correlated with panicle length thereby was correlated with the grain yield of rice. Genetic analysis of the morphological and physiological characteristics of functional leaves, especially flag leaf is found important for rice improvement program. It is noticed that when leaf length is high the panicle length is also high. Rahman et al. (2013) observed length of flag leaf and panicle of two rice cultivars, BR11 and BRRI dhan28 where flag leaf length positively correlates with yield and was highly significant. Plants with greater flag leaf length had elongated panicle length, thus producing increased number of primary and secondary rachis resulted in increased number of grains in the panicle that ultimately improved the yield of the variety. Flag leaf contributed to 45% of grain yield and is the single most component for yield loss. These results are in agreement with earlier reports on the contribution of flag leaf and top three leaves to grain yield (Misra and Misra, 1991). Table 1. Combined effect of varieties and leaf cutting on leaf length, breadth and area of rice Treatment Leaf length (cm) Leaf breadth (cm) Leaf area (cm2) F P T F P T F P T V1 37.22de 49.26cd 20.52cd 1.65bcd 1.56d 1.31fg 59.33cd 63.33c 29.67bc V2 38.52de 51.19bcd 18.26de 1.74ab 1.68cd 1.24g 61.67bcd 71.00b 32.33b V3 60.89b 66.86a 14.49f 1.77ab 1.84abc 1.83a 62.00bcd 59.00cd 25.67de V4 34.23e 28.49f 22.04bc 1.42e 1.38ef 1.44cd 42.67f 53.00ef 19.00f V5 38.60de 46.18d 25.82a 1.52de 1.30f 1.31efg 58.33d 51.00f 23.00e LSD(0.05) 5.48 6.59 3.08 0.16 0.17 0.10 3.99 5.07 2.66 CV (%) 7.06 7.47 8.59 5.88 6.32 4.13 3.96 4.71 5.59 Combined effect of varieties and leaf cutting on leaf length, breadth and area of rice. Means with different letters are significantly different at P≤0.05 by LSD test. Here, V1- V5; BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, BRRI dhan56, respectively and F, P, T denotes flag leaf, penultimate leaf and 3rd leaf, accordingly. bc b a cd cd de b de e cd 0 20 40 60 80 100 120 140 160 V1 V2 V3 V4 V5 Pl an t H ei gh t (c m ) C LC a bc a a cdbcd d bcd ab e 0 10 20 30 40 50 60 70 80 V1 V2 V3 V4 V5 Le af n u m b er a t h ea d in g C LCA B Growth and Yield of Aman Varieties as Influenced by Leaf Cutting 5 Thereby indicating, it is possible to improve grain yield by genetic improvement of length of flag leaf. Furthermore, the highest leaf breadth reduction in flag, penultimate and 3rd leaf were 8.33, 24.75 and 12.83% in V1, V5 and V5, respectively compared to control. Interestingly, variety V3 was reported with highest leaf breadth in all three mentioned leaves. Blake et al. (200) found that potential yield and Grain number were positively correlated with length, breadth and area of flag leaf. In terms of leaf area, the variety with highest value under leaf cutting condition is V3, V2 and V2 (62, 71 and 32 cm2 in flag, penultimate and 3rd leaf) respectively. However, less leaf area reduction in flag, penultimate and 3rd leaf was observed in V2, V2 and V1 variety, respectively compared to control (Table 1). The Grains yield and yield related traits were positively related to flag leaf area (Bassuony and Zsembeli, 2021). Prakash et al. (2011) found that the Grains yield was positively related with flag leaf area in rice varieties. Chlorophyll Content in flag Leaf Chlorophyll content of flag leaf at 12 days and at maturity from the study of five BRRI released rice varieties showed significant differences due to leaf cutting. Results indicated that flag leaf contained increased amount of total chlorophyll at 12 days than that of at maturity for all of the studied varieties. However, highest reduction of chl 27.56 and 35.30% in flag leaf at 12 days and maturity was resulted in V3 variety compared to control (Fig. 2). This might have happened due to the increased demand of photo assimilates for the growing panicle. Any damage done to that flag leaf will have a direct and dramatic impact on crops potential. Chlorophyll is positively correlated with photosynthetic rate. In rice, the leaf is metabolically active and critically important in determining yield. It has been assigned an important role in terms of supply of photosynthates to the grains (Suárez et al., 2021). Increased grain yield was observed by Rahman et al. (2013) in BRRI dhan34 when chlorophyll was higher. Abou-khalifa et al. (2008) also found the similar yield enhancing role of chl content in flag leaf in two rice cultivars. Fig. 2. Combined effect of varieties and leaf cutting on chl of flag leaf at 12 days after heading (A) and chl of flag leaf at maturity (B) of rice. Means with different letters are significantly different at P≤0.05 by LSD test. Here C, LC denotes control and leaf cutting, V1- V5; BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, BRRI dhan56, respectively. Effect of leaf cutting on yield contributing parameters of rice Different yield contributing characters viz. tillers hill-1, panicle hill-1, duration of grain filling, grain panicle-1, effective grain panicle-1 and filled grain% were significantly affected due to leaf cutting (Table 2). No significant variation of tillers hill-1 was observed due to leaf cutting whereas, the panicle number hill-1 were significantly reduced by leaf cutting. The highest reduction (31.26%) of panicle was observed in V5 variety and the lowest (10.16%) was in V3 variety, compared to cd a b a d e bc f bcd e 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 V1 V2 V3 V4 V5 C h l a t fl ag le af ( m g g-1 F W ) C LC a b b cd ef b c d e f 0.0 1.0 2.0 3.0 4.0 5.0 V1 V2 V3 V4 V5 C h l a t fl ag le af ( m g g-1 F W ) C LCA B 12 days after heading At maturity 6 Hossain et al. the control. However, significant variance in grain filling duration was not observed due to leaf cutting although except V3 in rest other varieties, leaf cutting delayed the grain filling duration. In terms of grains panicle-1, filled grains panicle-1 and filled grain% were not significantly reduced due to leaf cutting whereas 24.84, 29.72 and 49.43% highest reduction was resulted in V2, V2 and V5, respectively (Table 2). Due to reduced photo assimilation and reduced tiller number highly impacted on the panicle number of the rice that leads to reduced panicle size and resulted in reduction of other yield contributing characters. This finding corroborates with the earlier findings of Won et al. (2022) who reported that the greater sink size the higher is the grains panicle-1. Table 2. Combined effect of varieties and leaf cutting on yield contributing characteristics of rice Treatments No. of tiller hill-1 No. of panicle hill-1 Duration of grain filling No. of grains panicle-1 Filled grain panicle-1 Filled grain% C LC C LC C LC C LC C LC C LC V1 15.67ab 15.00b 17.70a 15.18b 33.00cd 34.67a-c 107.20cd 105.60cd 93.37b 89.38b 87.10ab 84.75ab V2 17.00a 15.00b 19.10c 14.39d 30.33de 35.33a-c 150.64a 113.23b 131.44a 92.37b 87.23ab 81.69bc V3 13.00c 12.67c 13.81d 12.41de 35.00a-c 29.00e 102.76d 104.35d 93.19b 90.78b 90.64a 86.98ab V4 11.33c 9.33d 16.41de 14.35e 36.33ab 37.33a 76.49e 66.32f 60.82c 50.67d 79.64bc 76.37c V5 13.00c 12.00c 15.36f 10.56g 31.00de 34.33bc 110.57bc 106.45cd 93.33b 92.97b 84.58ab 87.44ab LSD (0.05) 1.70 1.02 2.83 5.69 8.83 7.97 CV (%) 7.43 3.99 4.91 3.18 5.60 5.49 Combined effect of varieties and leaf cutting on yield contributing characteristics of rice. Means with different letters are significantly different at P≤0.05 by LSD test. Here, V1- V5; BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, BRRI dhan56, respectively and F, P, T denotes flag leaf, penultimate leaf and 3rd leaf, accordingly. Effect of leaf cutting on yield parameters of rice Grain parameters significantly varied due to leaf cutting (Fig. 3). The 1000-grain yield reduced in all tested varieties excepted increased in V5. The highest reduction of 1000-grain yield (13.43%) was observed in V2 variety (Fig. 3A). Significant variation in grain yield was observed in all varieties except V3 was observed under leaf cutting condition. The highest reduction of grain yield was (30.72%) in V2 variety compared to respective control (Fig, 3B). Straw yield significantly reduced under leaf cutting condition. However highest straw yield under leaf cutting condition was observed in V2 variety whereas the lowest was in V5 variety. On the contrary, V3 and V3 showed statistically similar yield. The highest reduction compared to control (31.79%) was observed in V5 followed by 25.05% in V2 variety (Fig. 3C). The harvest index showed no significant differences between the control and the variety treated with leaf cutting. Except V1 and V2, in rest three varieties leaf cutting increased harvest index significantly. In leaf cutting condition, the highest harvest index 56.51% followed by 54.74% was observed in V5 and V3, respectively (Fig. 3D). Results indicating yield was always significantly reduced when leaf was removed from the plant at panicle initiation stage. This is might be due to the inappropriate food supply to sink that mostly leaf does and thus the effect was observed as various defects in the floral identity. Therefore, it is worth mentioning that leaf has a great contribution on yield. Tambussi et al. (2007) also found the similar result and stated that grains filling is sustained by current photosynthesis of the upper parts of the plant, i.e., the flag leaf and penultimate leaves and the ear. Growth and Yield of Aman Varieties as Influenced by Leaf Cutting 7 Fig. 3. Combined effect of varieties and leaf cutting on yield parameters: 1000-grain weight (A), grain yield (B), straw yield (C), Harvest index (D) of rice. Means with different letters are significantly different at P≤0.05 by LSD test. Here C, LC denotes control and leaf cutting, V1- V5; BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, BRRI dhan56, respectively. Correlation with other parameters From correlation analysis, it has been resulted those different parameters showed strong relation between each other. Plant height showed strong correlation with most of the crop parameters. Third leaf length showed negative correlation with leaf breadth and leaf are. In addition, duration of grain filling notably impacted yield and yield contributing characters. Furthermore, harvest index has negatively affected by most of the plant parameters (Table 3). Gholizadeh et al. (2017) observed similar positive correlation among different leaf chl and nitrogen dynamics and their relationship to lowland rice yield for site-specific paddy management. Table 3. Correlation matrix of different plant parameters of rice Here, PH, LN, DGF, GP, FGP, TSW, GY, SY and HI denotes plant height, leaf number, duration of grain filling, grain panicle-1, filled grain panicle-1, 1000-seeds weight, grain yield, straw yield and harvest index cd bc a bcd dd d b cd cd 0 5 10 15 20 25 30 35 40 V1 V2 V3 V4 V5 10 00 -g ra in w ei gn t (g ) C LC b a b b b d c b c c 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 V1 V2 V3 V4 V5 G ra in y ie ld (t h a-1 ) C LC cd a c cd d e b e e f 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 V1 V2 V3 V4 V5 St ra w y ie ld (t h a-1 ) C LC bc d c c b c d a b a 0 10 20 30 40 50 60 70 V1 V2 V3 V4 V5 H ar ve st in de x (% ) C LC A B DC PH Flag Penul. 3rd Flag Penul. 3rd LN Flag Penul. 3rd 12-d-Head Maturity T. hill-1 P. hill-1 DGF GP FGP F. grain % TSW GY SY HI PH 1.00 Flag 0.49 1.00 Penul. 0.57 0.79 1.00 3rd -0.24 -0.55 -0.52 1.00 Flag 0.54 0.55 0.77 -0.61 1.00 Penul. 0.63 0.69 0.74 -0.53 0.65 1.00 3rd 0.15 0.83 0.49 -0.52 0.33 0.48 1.00 LN 0.17 0.21 0.09 -0.30 0.36 0.32 0.45 1.00 Flag 0.65 0.56 0.86 -0.27 0.71 0.61 0.14 -0.09 1.00 Penul. 0.60 0.17 0.51 -0.29 0.59 0.62 -0.07 0.33 0.61 1.00 3rd 0.66 0.17 0.58 -0.21 0.62 0.64 -0.19 0.13 0.71 0.90 1.00 12-d-Head 0.40 -0.08 -0.19 0.14 0.00 0.21 -0.02 0.53 -0.15 0.41 0.27 1.00 Maturity 0.45 0.15 0.44 -0.30 0.64 0.52 0.04 0.55 0.44 0.80 0.72 0.28 1.00 T. hill-1 0.52 0.07 0.49 -0.09 0.47 0.54 -0.28 -0.07 0.66 0.76 0.85 0.12 0.67 1.00 P. hill-1 0.19 -0.13 0.00 0.15 0.16 0.37 -0.11 0.46 0.10 0.64 0.53 0.69 0.58 0.50 1.00 DGF -0.13 -0.38 -0.44 0.06 -0.15 -0.45 -0.10 0.28 -0.50 -0.13 -0.23 0.26 -0.05 -0.38 -0.01 1.00 GP 0.55 0.23 0.57 -0.01 0.41 0.50 -0.21 -0.25 0.78 0.66 0.79 0.09 0.38 0.80 0.35 -0.49 1.00 FGP 0.58 0.32 0.64 -0.03 0.45 0.54 -0.13 -0.21 0.82 0.65 0.78 0.04 0.40 0.78 0.29 -0.52 0.97 1.00 F. grain % 0.44 0.47 0.63 -0.10 0.43 0.40 0.21 0.00 0.63 0.32 0.38 -0.20 0.29 0.39 -0.12 -0.38 0.42 0.63 1.00 TSW 0.45 0.73 0.56 -0.49 0.45 0.47 0.65 0.36 0.33 0.25 0.16 0.12 0.23 -0.06 -0.12 -0.20 0.08 0.22 0.52 1.00 GY 0.48 0.43 0.42 0.01 0.25 0.59 0.25 0.28 0.38 0.44 0.44 0.48 0.33 0.34 0.47 -0.52 0.49 0.51 0.27 0.43 1.00 SY 0.60 0.15 0.27 -0.06 0.34 0.58 -0.11 0.25 0.37 0.77 0.72 0.73 0.52 0.61 0.71 -0.22 0.63 0.58 0.07 0.20 0.71 1.00 HI -0.43 0.14 -0.03 0.15 -0.29 -0.33 0.30 -0.19 -0.18 -0.71 -0.63 -0.62 -0.50 -0.54 -0.63 -0.16 -0.39 -0.29 0.18 0.09 -0.11 -0.77 1.00 Leaf breadth Leaf area Chlorophyll (Flag leaf) Leaf length Leaf breadth Leaf area Chlorophyll (Flag leaf) Leaf length 8 Hossain et al. Conclusion Leaf cutting has a detrimental effect on the normal growth and physiology of the rice crops. In all tested varieties in the present study, control treatments were reported with highest plant growth, leaf, yield contributing and grain yield parameters compared to the varieties treated with leaf cutting. Based on the comparison of five rice varieties, BRRI dhan39 (V3) was found to be the highest yield producing variety in terms of greater flag leaf length, leaf breadth, flag leaf area, required less time to grain filling, filled grain panicle-1, filled grain%, 1000-grain weight, grain yield and harvest index in leaf cutting condition. BRRI dhan32 (V2) is the second highest performing variety considering plant height, chlorophyll content, tiller hill-1 and straw yield. Leaf cutting at heading (except flag leaf and penultimate leaves) reduced avarage10-20% loss of grain yield. It has been seen from this experiment that BRRI dhan39 show less effected by leaf cutting on the other hand BRRI dhan62 shown highly affected by leaf cutting. Hence it can be concluded that leaf cutting at heading stage is not a better practice and by developing the photosynthetic capacity of leaf is the key to overcome the photosynthate-source restriction on grain yield and to make a new breakthrough of yield potential in future development of rice. Acknowledgement The authors acknowledged the Farm division of Sher-e-Bangla Agricultural University to provide the input materials and Bangladesh Rice Research Institute (BRRI) to supply the quality seeds that supported us a lot to conduct the study. References Abou-khalifa, A.A.B., A.N. Misra and A.E.A.K.M. Salem. 2008. Effect of leaf cutting on physiological traits and yield of two rice cultivars. Afr. J. Plant Sci. 2(12): 147-150. Bassuony, N.N. and J. Zsembeli. 2021. Inheritance of some flag leaf and yield characteristics by half- diallel analysis in rice crops (Oryza sativa L.). Cereal Res. Commun. 49(3): 503-510. Blake, N.K., S.P. Lanning, J.M. Martin, J.D. Sherman and L.E. Talbert. 2007. Relationship of flag leaf characteristics to economically important traits in two spring wheat crosses. Crop Sci. 47(2): 491-494. Confalonieri, R., S. Bregaglio, A.S. Rosenmund, M. Acutis and I. Savin. 2011. A model for simulating the height of rice plants. Eur. J. Agron. 34(1): 20-25. Das, S.R., M.Y. Ali and M.M. Islam. 2017. Effect of leaf clipping on yield attributes of modern and local rice varieties. Bangladesh Rice J. 21(1): 101-104. Gholizadeh, A., M. Saberioon, L. Borůvka, A. Wayayok and M.A.M. Soom. 2017. Leaf chlorophyll and nitrogen dynamics and their relationship to lowland rice yield for site-specific paddy management. Inf. Process. Agric. 4(4): 259-268. Islam, A.R.M., S. Shen, S. Yang, Z. Hu and R. Chu. 2019. Assessing recent impacts of climate change on design water requirement of Boro rice season in Bangladesh. Theor. Appl. Climatol. 138(1): 97-113. Karmakar, B. and B. Karmakar. 2019. Effect of nitrogen rates and leaf clipping on forage and grain yield, and seed quality of transplant Aman rice. Bangladesh Rice J. 23(2): 49-57. Mahamud, J.A., M.M. Haque and M. Hasanuzzaman. 2013. Growth, dry matter production and yield performance of transplanted Aman rice varieties influenced by seedling densities per hill. Int. J. Sustain. Agric. 5(1): 16-24. Growth and Yield of Aman Varieties as Influenced by Leaf Cutting 9 Mazumder, S.R., H. Hoque, B. Sinha, W.R. Chowdhury, M.N. Hasan and S.H. Prodhan. 2020. Genetic variability analysis of partially salt tolerant local and inbred rice (Oryza sativa L.) through molecular markers. Heliyon. 6(8): e04333. doi:10.1016/j.heliyon.2020.e04333. Mazur, V.A., H.V. Pantsyreva, K.V. Mazur and I.M. Didur. 2019. Influence of the assimilation apparatus and productivity of white lupine plants. Agron. Res. 17(1): 206–219. Misra, A.N. and M. Misra. 1991. Physiolgocal responses of pearl millet to agroclimatic conditions. In: R. Prakash and A. Ali (eds.) Environmental Contamination and Hygien. Jagmandir Books, New Delhi, India. pp. 165-175. Prakash, M., A. Anandan and B.S. Kumar. 2011. Varietal variations in flag leaf area and yield in mutant lines of PY 5 rice. Karnataka J. Agric. Sci. 24(4): 525-526. Rahman, M.A., M.E. Haque, B. Sikdar, M.A. Islam and M.N. Matin. 2013. Correlation analysis of flag leaf with yield in several rice cultivars. J. Life Earth Sci. 8: 49-54. Shang, F., X. Chao, K. Meng, X. Meng, Q. Li, L. Chen and J. Wang. 2020. Fine mapping of a grain shape gene from a rice landrace longliheinuo-dwarf (Oryza sativa L. ssp. Japonica). Agron. 10(3): 380. doi:10.3390/agronomy10030380. Suárez, J.C., J.A. Polanía, J.A. Anzola, A.T. Contreras, D.L. Méndez, J.I. Vanegas, J.E. Noriega, L. Rodríguez, M.O. Urban, S. Beebe and I.M. Rao. 2021. Influence of nitrogen supply on gas exchange, chlorophyll fluorescence and grain yield of breeding lines of common bean evaluated in the Amazon region of Colombia. Acta Physiol. Plant. 43(4): 1-15. Suprio, C., K.D. Pradip, G. Biswajit, K.S. Kalyan and B. Bhubaneswar. 2010. Quantitative genetic analysis for yield and yield component in rice. Sci. Biol. 2(1): 117-120. Tambussi, E.A., J. Bort, J.J. Guiamet, S. Nogués and J.L. Araus. 2007. The photosynthetic role of ears in C3 cereals: metabolism, water use efficiency and contribution to grain yield. Crit. Rev. Plant Sci. 26(1): 1-16. Won, P.L.P., N. Kanno, N.P. Banayo, C.S. Bueno, P.S. Cruz and Y. Kato. 2022. Source–sink relationships in short-duration and hybrid rice cultivars in tropical Asia. Field Crops Res. 282: 108485. doi:10.1016/j.fcr.2022.108485.